An accelerated Branch-and-Bound algorithm for assignment problems of utility systems

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higher education crossing borders

2 Cross-border Education: Complexities and Challenges…………… 19
• What is cross-border education? • New developments in cross-border education • Who are the cross-border providers? • How do programs move across borders? • How do traditional and new providers move across borders? • Varying perspectives on rationales and impacts of cross-border education
The designations employed and the presentation of material throughout this publication do not imply the expression of any opinion whatsoever on the part of UNESCO concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.
The authors are responsible for the choice and the presentation of the facts contained in this book and for the opinions expressed therein, which are not necessarily those of UNESCO and do not commit the Organization.

墨菲物流学英文版第12版课后习题答案

PART IIANSWERS TO END-OF-CHAPTER QUESTIONSCHAPTER 14: INTERNATIONAL LOGISTICS14-1. Discuss some of the key political restrictions on cross-border trade.Political restrictions on cross-border trade can take a variety of forms. Many nations ban certain types of shipments that might jeopardize their national security. Likewise, individual nations may band together to pressure another country from being an active supplier of materials that could be used to build nuclear weapons. Some nations restrict the outflow of currency because a nation,s economy will suffer if it imports more than it exports over a long term. A relatively commonpolitical restriction on trade involves tariffs, or taxes that governments place on the importation of certain items. Another group of political restrictions can be classified as nontariff barriers, which refer to restrictions other than tariffs that are placed upon imported products. Another political restriction involves embargoes, or the prohibition of trade between particular countries.14-2. How might a particular country,s government be involved in international trade?Governments may exert strong control over ocean and air traffic because they operate as extensions of a nation,s economy and most of the revenue flows into that nation's economy. In some cases, import licenses may restrict movement to a vessel or plane owned or operated by the importing country. In addition, some nations provide subsidies to develop and/or maintain their ocean and air carriers. Governments also support their own carriers through cargo preference rules, which require a certain percentage of traffic to move on a nation,s flag vessels. Although federal governments have often owned ocean carriers and international airlines, some government-owned international carriers are moving toward the private sector.14-3. Discuss how a nation,s market size might impact international trade and, in turn,international logistics.Population is one proxy for market size, and China and India account for about one-third of the world's population. As such, these two countries might be potentially attractive markets because of their absolute and relative size. Having said this, India has a relatively low gross domestic product per capita, and because of this some customers buy singleuse packets of products called sachets. From a logistical perspective, single-use packets require different packaging, and are easier to lose and more prone to theft than products sold in larger quantities.14-4. How might economic integration impact international logistics?Potential logistical implications of economic integration include reduced documentation requirements, reduced tariffs, and the redesign of distribution networks. For example,Poland and the Czech Republic have become favorite distribution sites with the eastward expansion of the European Union.14-5. How can language considerations impact the packaging and labeling of international shipments?With respect to language, cargo handlers may not be able to read and understand the language of the exporting country, and it would not be unusual for cargo handlers in some countries to beilliterate. Hence, cautionary symbols, rather than writing, must be used. A shipper,s mark, which looks like a cattle brand, is used in areas where dockworkers cannot read but need a method to keep documents and shipments together.14-6. What is a certificate of origin, a commercial invoice, and a shipper,s export declaration?A certificate of origin specifies the country or countries in which a product is manufactured .This document can be required by governments for control purposes or by an exporter to verify thelocation of manufacture. A commercial invoice is similar in nature to a domestic bill of lading in the sense that a commercial invoice summarizes the entire transaction and contains (or should contain) key information to include a description of the goods, the terms of sale and payment, the shipment quantity, the method of shipment, and so on. A shipper,s export declaration contains relevant export transaction data such as the transportation mode(s), transaction participants, and a description of what is being exported.14-7. Discuss international terms of sale and Incoterms.International terms of sale determine where and when buyers and seller will transfer 1) the physical goods; 2) payment for goods, freight charges, and insurance for the in-transit goods; 3) legal title to the goods; 4) required documentation; and 5) responsibility for controlling or caring for the goods in transit. The International Chamber of Commerce is in charge of establishing, and periodically revising, the terms of sale for international shipments, commonly referred to as Incoterms. The most recent revision, Incoterms 2010, reflects the rapid expansion of global trade with a particular focus on improved cargo security and new trends in cross-border transportation. Incoterms 2010 are now organized by modes of transport and the terms can be used in both international and domestic transportation.14-8. Name the four methods of payment for international shipments. Which method is riskiest for the buyer? For the seller?Four distinct methods of payment exist for international shipments: cash in advance, letters of credit, bills of exchange, and the open account. Cash in advance is of minimal risk to the seller, but is the riskiest for the buyer-what if the paid-for product is never received? The open account involves tremendous potential risk for the seller and minimal risk for the buyer.14-9. Discuss four possible functions that might be performed by international freight forwarders.The text describes eight functions, such as preparing an export declaration and booking space on carriers, so discussion of any four would be appropriate.14-10. What is an NVOCC?An NVOCC (nonvessel-operating common carrier) is often confused with an international freight forwarder. Although both NVOCCs and international freight forwarders must be licensed by the Federal Maritime Commission, NVOCCs are common carriers and thus have common carrier obligations to serveand deliver, among other obligations. NVOCCs consolidate freight from different shippers and leverage this volume to negotiate favorable transportation rates from ocean carriers. From the shipper's perspective, an NVOCC is a carrier; from an ocean carrier,s perspective, an NVOCC is a shipper.14-11. What are the two primary purposes of export packing?One function is to allow goods to move easily through customs. For a country assessing duties on the weight of both the item and its container, this means selecting lightweight packing materials. The second purpose of export packing is to protect products in what almost always is a more difficult journey than they would experience if they were destined for domestic consignees.14-12. Discuss the importance of water transportation for international trade.A frequently cited statistic is that approximately 60 percent of cross-border shipments move by water transportation. Another example of the importance of water transportation in international trade involves the world,s busiest container ports as measured by TEUs (twenty-foot equivalent units) handled; 9 of the 10 busiest container ports are located in Asia, with 7 of the busiest ports located in China.14-13. Explain the load center concept. How might load centers affect the dynamics of international transportation?Load centers are major ports where thousands of containers arrive and depart each week. As vessel sizes increase, it becomes more costly to stop at multiple ports in a geographic area, and as a result, operators of larger container ships prefer to call at only one port in a geographic area. Load centers might impact the dynamics of international trade in the sense that some ports will be relegated to providing feeder service to the load centers.14-14. Discuss the role of ocean carrier alliances in international logistics.In the mid-1990s, ocean carrier alliances, in which carriers retain their individual identities but cooperate in the area of operations, began forming in the container trades. These alliances provide two primary benefits to participating members, namely, the sharing of vessel space and the ability to offer shippers a broader service network. The size of the alliance allows them to exercise considerable clout in their dealings with shippers, port terminal operators, and connecting land carriers.14-15. How do integrated air carriers impact the effectiveness and efficiency of international logistics?Integrated air carriers own all their vehicles and the facilities that fall in-between. These carriers often provide the fastest service between many major points. They are also employed to carry the documentation that is generated by—and is very much a part of— the international movement of materials. The integrated carriers also handle documentation services for their clients.14-16. How do open-skies agreements differ from bilateral agreements?Bilateral agreements generally involved two countries and tended to be somewhat restrictive in nature. For example, the bilateral agreements would specify the carriers that were to serve particular city pairs. By contrast, open skies agreements liberalize aviation opportunities andlimit federal government involvement. For example, the Open Aviation Agreement between the United States and 27 European Union (EU) member states allows any EU airline as well as any U.S. airline to fly between any point in the EU and any point in the United States.14-17. Discuss the potential sources of delays in certain countries with respect to motor carrier shipments that move across state borders.One source of delays is that certain countries limit a motor carrier,s operations to within a particular state,s borders; as a result, multi-state shipments must be transferred from one company,s vehicle to another company,s vehicle whenever crossing into another state. Another source of delays is that certain countries conduct inspections of trucks as they move from one state to another. This can include physical counting and inspection of all shipments, inspection of documentation, and vehicle inspection, as well as driver inspection.14-18. Define what is meant by short-sea shipping (SSS), and discuss some advantages of SSS.Short-sea shipping (SSS) refers to waterborne transportation that utilizes inland and coastal waterways to move shipments from domestic ports to their destination. Potential benefits to SSS include reduced rail and truck congestion, reduced highway damage, a reduction in truck-related noise and air pollution, and improved waterways utilization.14-19. What are some challenges associated with inventory management in cross-border trade?Because greater uncertainties, misunderstandings, and delays often arise in international movements, safety stocks must be larger. Furthermore, inventory valuation on an international scale isdifficult because of continually changing exchange rates. When a nation,s (or the world's) currency is unstable, investments in inventories rise because they are believed to be less risky than holding cash or securities.Firms involved in international trade must give careful thought to their inventory policies, in part because inventory available for sale in one nation may not necessarily serve the needs of markets in nearby nations. Product return policies are another concern with respect to international inventory management. One issue is that, unlike the United States where products can be returned for virtually reason, some countries don,t allow returns unless the product is defective in some respect.14-20. What is the Logistics Performance Index? How can it be used?The Logistics Performance Index (LPI) was created in recognition of the importance of logistics in global trade. The LPI measures a country,s performance across six logistical dimensions:•Efficiency of the clearance process (i.e., speed, simplicity, and predictability of formalities) by border control agencies, including customs;•Quality of trade- and transport-related infrastructure (e.g., ports, railroads, roads, and information technology);•Ease of arranging competitively priced shipments;•Competence and quality of logistics services (e.g., transport operators and customs brokers);•Capability to track and trace consignments;•Timeliness of shipments in reaching the destination within the scheduled or expected delivery time.The LPI is a potentially valuable international logistics tool because the data can be analyzed from several different perspectives. First, the LPI can be analyzed for all countries according to the overall LPI score as well as according to scores on each of the six dimensions. Second, the LPI can be analyzed in terms of an individual country's performance over time, relative to its geographic region, and relative to its income group.PART IIICASE SOLUTIONSCASE 14-1: Nurnberg Augsburg Maschinenwerke (N.A.M.)Question 1: Assume that you are Weiss. How many viable alternatives do you have to consider regarding the initial shipment of 25 buses?The answer to this question can vary depending on how students define “viable alternatives.” If we take a broad perspective and just focus on the primary cities, Bremerhaven does not appear to be an option because there is no scheduled liner service in the desired time frame. That leaves us with Prague to Santos through Hamburg and Prague to Santos through Rotterdam. Several of the vessel departure dates for both alternatives are not feasible. For example, the 18-day transit time from Hamburg eliminates both the October 31 and November 3 departures; likewise, the 17-day transit time from Rotterdam eliminates the November 2 departure. And although the October 27 departure from Hamburg or the October 28 departure from Rotterdam should get the buses to Santos by November 15, neither departure leaves much room for potential transit delays (e.g., a late season hurricane). As such, it appears that Weiss has but two viable alternatives: the October 24 departure from Hamburg and the October 23 departure from Rotterdam.Question 2: Which of the routing alternatives would you recommend to meet the initial 90-day deadline for the 25-bus shipment? Train or waterway? To which port(s)? What would it cost?If one assumes that rail transport is used from Prague to either Hamburg or Rotterdam, then thetotal transportation costs of the two alternatives are virtually identical. Although rail costs to Rotterdam are €300 higher than to Hamburg, the shipping costs from Rotterdam are €300 lower than from Hamburg (based on €6000 x .95). Because the total transportation costs are essentially the same, the decision likely needs to be based on service considerations. The initial shipment is extremely important. It might be suggested that Prague to Hamburg by rail and Hamburg to Santos by ocean vessel is the preferred alternative. Our rationale is that the provided transit times with Hamburg are definitive— that is, 3 days by rail and 18 days by water. With Rotterdam, by contrast, the rail transit time is either 4 or 5 days, although water transportation is 17 days.Question 3: What additional information would be helpful for answering Question 2?A variety of other information would be helpful for answering Question 2. For example, the case offers no insight about port congestion issues and how this congestion might impact the timeliness of shipment loadings. There also is no information about port performance in terms of loss and damage metrics. In addition, although the case indicates that rail transit time from Prague iseither four or five days, it might be helpful to know what percentage of shipments is completed in four days. Students are likely to come up with more suggestions.Question 4: How important, in fact, are the transport costs for the initial shipment of 25 buses?Clearly, with ocean shipping costs of either €5700 or €6000 per bus, transportation costs cannot be ignored. Having said this, the initial shipment holds the key to the remainder of the order (another 199 buses) and appears to be instrumental in securing another order for 568 buses (for a total of 767 more buses). As such, N.A.M might be somewhat flexible with respect to transportation costs for the initial shipment. Suppose, for example, that N.A.M. can earn a profit of €5000 per bus (such profit on a €120000 bus is by no means exorbitant). A profit of €5000 x 767 buses yields a total profit of €3,835,000. Because of such a large upside with respect to additional orders,N.A.M. might focus on achieving the specified metrics for the initial shipment without being overly concerned with transportation costs.Question 5: What kinds of customer service support must be provided for this initial shipment of 25 buses? Who is responsible?Although a number of different constituencies is involved in the initial shipment (e.g., railroads, dock workers, ocean carrier, etc.), the particular customers—the public transit authorities—are buying product from N.A.M. Because of this, N.A.M. should be the responsible party with respect to customer service support. There are myriad customer service support options that might be provided. Real-time shipment tracking should be an option so that the customers can know, at any time, the location of the shipment. N.A.M. might also provide regular updates of shipment progress; perhaps N.A.M. could email or fax important progress points (e.g., the shipment has left Prague; the shipment has arrived in Hamburg, etc.) to the customers. Because successful performance on theinitial shipment is crucial to securing future business, N.A.M. might have one of its managers actually accompany the shipment.Question 6: The Brazilian buyer wants the buses delivered at Santos. Weiss looks up theInternational Chamber of Commerce,s Incoterms and finds three categories of “delivered” terms:DAT (Delivered at Terminal). In this type of transaction, the seller clears the goods forexport and bears all risks and costs associated with delivering the goods and unloading them at the terminal at the named port or place of destination. The buyer is responsible for all costs and risks from this point forward including clearing the goods for import at the named country of destination.DAP (Delivered at Place). The seller clears the goods for export and bears all risks and costs associated with delivering goods to the named place of destination not unloaded. The buyer is responsible for all costs and risks associated with unloading the goods and clearing customs to import goods into the named country of destination.DDP (Delivered Duty Paid). The seller bears all risks and costs associated with delivering the goods to the named place of destination ready for unloading and clearing for import.How should he choose? Why?Again, given the importance of the initial shipment, it would appear that the more control thatN.A.M. has over the process, the better. Although the DDP option is likely the costliest option, it also affords N.A.M. more control later into the shipment process. Moreover, a willingness by N.A.M. to take on the additional costs associated with DDP might be viewed in a positive fashion by the customers.Question 7: Would you make the same routing recommendation for the second, larger (199 buses) component of the order, after the initial 90-day deadline is met? Why or why not?Time pressures do not appear to be as critical for the larger component of the order, so this might argue for use of water transportation between Prague and Hamburg. The rationale would be that even though water transportation is slower, it saves money (€48 per bus) over rail shipments. Alternatively, given that the selling price per bus is likely to be around €120000, trading off three days of transit time in exchange for a savings of €48 might not be such a good idea.Question 8：How important, if at all, is it for N.A.M. to ship via water to show its support of the European Union,s Motorways of the Seas concept?This question may generate a variety of opinions from students. For example, some students might argue that Question 75s answer also applies to Question 8. Having said this, the case doesn,t delve too deeply into potential environmental considerations associated with water transportation, so a pure cost-benefit analysis (such as Question 7) might be insufficient. Furthermore, because the European Union (EU) continues to be a contentious issue for many Europeans, the answer to Question 8 might depend upon one,s view of the EU. Thus, someone who is supportive of the EU might lean toward supporting the Motorways of the Seas concept, while someone not supportive of the EU might lean against supporting the Motorways of the Seas concept.。

东盟政治安全共同体蓝图(英文版)

ASEAN Political-Security Community BlueprintASEAN POLITICAL-SECURITY COMMUNITY BLUEPRINT 1 ASEAN POLITICAL-SECURITY COMMUNITY BLUEPRINTI. INTRODUCTION1. The ASEAN Political-Security Community has its genesis of over four decades of close co-operation and solidarity. The ASEAN Heads of States/Governments, at their Summit in Kuala Lumpur in December 1997 envisioned a concert of Southeast Asian nations, outward looking, living in peace, stability and prosperity, bonded together in partnership in dynamic development and ina community of caring societies.2. To concretise the ASEAN Vision 2020, the ASEAN Heads of States/Governments adopted the Declaration of ASEAN Concord II (Bali Concord II) in 2003, which establishes an ASEAN Community by 2020. The ASEAN Community consists of three pillars, namely the ASEAN Political-Security Community (APSC), the ASEAN Economic Community (AEC) and the ASEAN Socio-Cultural Community (ASCC).3. Conscious that the strengthening of ASEAN integration through accelerated establishment of an ASEAN Community will reinforce ASEAN’s centrality and role as the driving force in charting the evolving regional architecture, the ASEAN Leaders at the 12th ASEAN Summit in the Philippines decided to accelerate the establishment of an ASEAN Community by 2015.4. At the 13th ASEAN Summit in Singapore, the ASEAN Heads of States/Governments signed the ASEAN Charter, which marked ASEAN Member States’ commitment in intensifying community-building through enhanced regional cooperation and integration. In line with this, they tasked their Ministers and officials to draft the APSC Blueprint, which would be adopted at the 14th ASEAN Summit.5. The APSC Blueprint is guided by the ASEAN Charter and the principles and purposes contained therein. The APSC Blueprint builds on the ASEAN Security Community Plan of Action, the Vientiane Action Programme (VAP), as well as relevant decisions by various ASEAN Sectoral Bodies. The ASEAN Security Community Plan of Action is a principled document, laying out the activities needed to realise the objectives of the ASEAN Political Security Community, while the VAP lays out the measures necessary for 2004-2010. Both documents are important references in continuing political and security cooperation. The APSC Blueprint provides a roadmap and timetable to establish the APSC by 2015. The APSC Blueprint would also have the flexibility to continue programmes/activities beyond 2015 in order to retain its significance and have an enduring quality. II. CHARACTERISTICS AND ELEMENTS OF THE APSC6. It is envisaged that the APSC will bring ASEAN’s political and security cooperation to a higher plane. The APSC will ensure that the peoples and Member States of ASEAN live in peace with one another and with the world at large in a just, democratic and harmonious environment.7. The APSC shall promote political development in adherence to the principles of democracy, the rule of law and good governance, respect for and promotion and protection of human rightsa)b)c)and fundamental freedoms as inscribed in the ASEAN Charter. It shall be a means by which ASEAN Member States can pursue closer interaction and cooperation to forge shared norms and create common mechanisms to achieve ASEAN’s goals and objectives in the political and security fields. In this regard, it promotes a people-oriented ASEAN in which all sectors of society, regardless of gender, race, religion, language, or social and cultural background, are encouraged to participate in, and benefit from, the process of ASEAN integration and community building. In the implementation of, the Blueprint, ASEAN should also strive towards promoting and supporting gender-mainstreaming, tolerance, respect for diversity, equality and mutual understanding.8. At the same time, in the interest of preserving and enhancing peace and stability in the region, the APSC seeks to strengthen the mutually beneficial relations between ASEAN and its Dialogue Partners and friends. In doing so, it also maintains the centrality and proactive role of ASEAN in a regional architecture that is open, transparent and inclusive, while remaining actively engaged, forward-looking and non-discriminatory.9. The APSC subscribes to a comprehensive approach to security, which acknowledges the interwoven relationships of political, economic, social-cultural and environmental dimensions of development. It promotes renunciation of aggression and of the threat or use of force or other actions in any manner inconsistent with international law and reliance of peaceful settlements of dispute. In this regard, it upholds existing ASEAN political instruments such as the Declaration on Zone of Peace, Freedom and Neutrality (ZOPFAN), the Treaty of Amity and Co-operation in South East Asia (TAC) and the Treaty on the Southeast Asian Nuclear Weapon-Free Zone (SEANWFZ), which play a pivotal role in the area of confidence building measures, preventive diplomacy and pacific ap-proaches to conflict resolution. It also seeks to address non-traditional security issues.10. Based on the above, the ASEAN Political-Security Community envisages the following three key characteristics:A Rules-based Community of shared values and norms; A Cohesive, Peaceful, Stable and Resilient Region with shared responsibility for comprehensive security; andA Dynamic and Outward-looking Region in an increasingly integrated and interdependent world.11. These characteristics are inter-related and mutually reinforcing, and shall be pursued in a balanced and consistent manner. To effectively realise the APSC, the APSC Blueprint is an action-oriented document with a view to achieving results and recognises the capacity and capability of ASEAN Member States to undertake the stipulated actions in the Blueprint.A. A Rules-based Community of Shared Values and Norms12. ASEAN’s cooperation in political development aims to strengthen democracy, enhance good governance and the rule of law, and to promote and protect human rights and fundamental freedoms, with due regard to the rights and responsibilities of the Member States of ASEAN, so as to ultimately create a Rules-based Community of shared values and norms. In the shaping and sharing of norms, ASEAN aims to achieve a standard of common adherence to norms of good conduct among2 ASEAN POLITICAL-SECURITY COMMUNITY BLUEPRINTi.ii.iii.i.member states of the ASEAN Community; consolidating and strengthening ASEAN’s solidarity, cohesiveness and harmony; and contributing to the building of a peaceful, democratic, tolerant, participatory and transparent community in Southeast Asia.13. Moreover, cooperation in political development will bring to maturity the political elements and institutions in ASEAN, towards which the sense of inter-state solidarity on political systems, culture and history will be better fostered. Such inter-state solidarity can be achieved further through the shaping and sharing of norms.A.1. Cooperation in Political Development14. Since the adoption of the ASC Plan of Action in 2003, ASEAN has achieved progress in different measures of political development. There was increased participation by organisations, such as academic institutions, think-tanks, and civil society organisations in ASEAN meetings and activities. Such consultations and heightened interactions fostered good relations and resulted in positive outcomes for the region.15. Efforts are underway in laying the groundwork for an institutional framework to facilitate free flow of information based on each country’s national laws and regulations; preventing and combating corruption; and cooperation to strengthen the rule of law, judiciary systems and legal infrastructure, and good governance. Moreover, in order to promote and protect human rights and fundamental freedoms, the ASEAN Charter stipulates the establishment of an ASEAN human rights body.A.1.1.Promote understanding and appreciation of political systems, culture and historyof ASEAN Member States Actions:A.1. 2. Lay the groundwork for an institutional framework to facilitate free flow of information for mutual support and assistance among ASEAN Member States Actions:Assign appropriate ASEAN sectoral bodies to take necessary measures to promote understanding and appreciation of political systems, culture and history of ASEANMember States, which will undertake to:a. Encourage the holding of at least two track-two events per year, includingacademic conferences, workshops and seminars;b. Release periodic publications on the dynamics of ASEAN Member States’political systems, culture and history for dissemination to the public; andc. Intensify exchange of experience and training courses in order to enhancepopular and broader participation.Hold seminars/workshops to share experiences on democratic institutions, gender mainstreaming, and popular participation; andEndeavour to compile best practices of voluntary electoral observations.Encourage the ASEAN Ministers Responsible for Information (AMRI) to develop an ASEAN POLITICAL-SECURITY COMMUNITY BLUEPRINT 3ii.iii.iv.v.i.ii.iii.iv.i.ii.iii.iv.A.1.3.Establish programmes for mutual support and assistance among ASEANMember S tates in the development of strategies for strengthening the rule of lawand judiciary systems and legal infrastructure Actions:A.1.4. Promote good governanceActions:institutional framework to facilitate free flow of information, based on each country’s national laws, by establishing an information baseline of these laws and to submit a progress report to the ASEAN Political-Security Community Council;Request each ASEAN Member State to develop relevant media exchange programmes to aid free flow of information, starting within three months from the adoption of this Blueprint;Enhance media capacity to promote regional-community building, explore the possibility of establishing an ASEAN media panel to boost cooperation and collaboration among the media-related institutions and organizations with emphasis on the process of the implementation of the APSC Blueprint;Implement internships, fellowships, scholarships and workshops, study visits and journalist exchange programs to enhance media capacity and professionalism in the region with emphasis on the process of the implementation of the APSC Blueprint; and Facilitate co-production and exchanges of films, TVs, animations, games and new media content to promote cultural exchanges with emphasis on the process of theimplementation of the APSC Blueprint.Entrust ASEAN Law Ministers Meeting (ALAWMM), with the cooperation of other sectoral bodies and entities associated with ASEAN including ASEAN Law Association(ALA) to develop cooperation programmes to strengthen the rule of law, judicialsystems and legal infrastructure;Undertake comparative studies for lawmakers on the promulgation of laws and regulations;Develop a university curriculum on the legal systems of ASEAN Member States by theASEAN University Network (AUN) by 2010; andEnhance cooperation between ALAWMM and ALA and other Track II organisations through seminars, workshops and research on international law, including ASEANagreements.Conduct analytical and technical studies to establish baselines, benchmarks, and best practices in various aspects of governance in the region;Promote sharing of experiences and best practices through workshops and seminars on leadership concepts and principles with emphasis on good governance, and ondeveloping norms on good governance;Conduct a study by 2009 on partnership between public and private sectors andacademia in creating a conducive climate for good governance to provide concreterecommendations to appropriate ASEAN sectoral bodies; andPromote dialogue and partnership among governments, private sectors and other relevant organisations to foster and enable new ideas, concepts and methods with aview to enhance transparency, accountability, participatory and effective governance.4 ASEAN POLITICAL-SECURITY COMMUNITY BLUEPRINTi.ii.iii.iv.v.vi.vii.i.ii.iii.iv.i.ii.iii.iv.A.1.5. Promotion and Protection of human rightsActions:A.1.6. Increase the participation of relevant entities associated with ASEAN in moving forward ASEAN political development initiativesActions:A.1.7. Prevent and combat corruptionActions:Establish an ASEAN human rights body through the completion of its Terms of Reference (ToR) by 2009 and encourage cooperation between it and existing humanrights mechanisms, as well as with other relevant international organizations;Complete a stock-take of existing human rights mechanisms and equivalent bodies, including sectoral bodies promoting the rights of women and children by 2009;Cooperate closely with efforts of the sectoral bodies in the development of an ASEANinstrument on the protection and promotion of the rights of migrant workers;Strengthen interaction between the network of existing human rights mechanisms as well as other civil society organisations, with relevant ASEAN sectoral bodies;Enhance/conduct exchange of information in the field of human rights among ASEAN countries in order to promote and protect human rights and fundamental freedomsof peoples in accordance with the ASEAN Charter and the Charter of the UnitedNations, and the Universal Declaration of Human Rights and the Vienna Declarationand Programme of Action;Promote education and public awareness on human rights; andCooperate closely with efforts of the sectoral bodies in the establishment of an ASEANcommission on the promotion and protection of the rights of women and children.Develop modalities for interaction between relevant entities associated with ASEAN, such as the ASEAN-ISIS network, and ASEAN sectoral bodies;Promote research studies and scholarly publications on ASEAN political development initiatives;Hold consultations between AIPA and appropriate ASEAN organs; andRevise the Memorandum of Understanding of the ASEAN Foundation to take into account the provisions of the ASEAN Charter.Identify relevant mechanisms to carry out cooperation activities in preventing and combating corruption and strengthen links and cooperation between the relevantagencies;Encourage all ASEAN Member States to sign the Memorandum of Understanding (MoU) on Cooperation for Preventing and Combating Corruption signed on 15 December2004;Promote ASEAN cooperation to prevent and combat corruption, bearing in mind theabove MoU, and other relevant ASEAN instruments such as the Treaty on Mutual LegalAssistance in Criminal Matters (MLAT);Encourage ASEAN Member States who are signatories to the United Nations Convention ASEAN POLITICAL-SECURITY COMMUNITY BLUEPRINT 5v.i.ii.iii.i.ii.iii.iv.v.vi.i.ii.A.1.8.Promote Principles of Democracy Actions:A.1.9. Promote peace and stability in the regionActions:A.2.Shaping and Sharing of Norms 16. ASEAN promotes regional norms of good conduct and solidarity, in accordance with the key principles enshrined in the ASEAN Charter. In this context, ASEAN also continues to uphold the Treaty of Amity and Co operation in Southeast Asia (TAC), the SEANWFZ Treaty and other key agreements, as well as the Declaration on the Conduct of Parties (DOC) in the South China Sea.A.2.1.Adjust ASEAN institutional framework to comply with the ASEAN Charter Actions:against Corruption to ratify the said Convention; and Promote the sharing of best practices, exchange views and analyse issues related to values, ethics and integrity through appropriate avenues and fora and taking into account inputs from various seminars such as the ASEAN Integrity Dialogue.Promote understanding of the principles of democracy among ASEAN youth at schoolsat an appropriate stage of education, bearing in mind the educational system in therespective ASEAN Member States;Convene seminars, training programmes and other capacity building activities forgovernment officials, think-tanks and relevant civil society organizations to exchangeviews, sharing experiences and promote democracy and democratic institutions; andConduct annual research on experiences and lessons-learned of democracy aimed atenhancing the adherence to the principles of democracy.Support the inclusion of culture of peace which includes, inter alia, respect for diversity,promotion of tolerance and understanding of faiths, religions and cultures in thecurriculum of ASEAN academic institutions;Develop programmes and activities aimed at the promotion of culture of peace,interfaith and intrafaith dialogue within the region;Promote respect and appreciation for the region’s diversity and harmony among thepeoples of the region;Promote dialogue and greater interaction among various religious and ethnic groups;Promote networking among schools in the region to develop peace-education in theirrespective curricula; andSupport poverty alleviation and narrowing development gaps to contribute topromoting sustained peace and stability in the region.Prepare and implement a transitional work plan on the necessary institutional reformsneeded to comply with the ASEAN Charter;Develop, as appropriate, supplemental protocols and/or agreements, including terms 6 ASEAN POLITICAL-SECURITY COMMUNITY BLUEPRINTA.2.2. Strengthening Cooperation under the TACActions:A.2.3. Ensure full implementation of the DOC for peace and stability in the South China Sea Actions:A.2.4. Ensure the implementation of South East Asian Nuclear Weapon-Free Zone (SEAN WFZ) Treaty, and its Plan of ActionActions:A.2.5. Promote ASEAN Maritime CooperationActions:iii.i.ii.iii.i.ii.iii.iv.i.ii.iii.i.ii.iii.iv.of references and rules of procedures, needed to implement the ASEAN Charter; andDevelop a legal division to support the implementation of the ASEAN Charter.Convene workshops and seminars to assess the progress of the implementation of theTAC and explore ways to improve its mechanisms;Convene a conference of High Contracting Parties to the TAC to review its implementation;andEncourage the accession to the TAC by non-ASEAN countries.Continue ASEAN’s current practice of close consultation among Member States toachieve full implementation of the DOC;Explore and undertake cooperative activities identified in the DOC and eventuallyexplore other co-operative measures on the basis of close consultation among themember countries, while respecting sovereignty and integrity of each other;Carry out on a regular basis the overview of the process of implementation of the DOC,thus ensuring timely and proper conducts of the Parties in the South China Sea inaccordance with the DOC; andWork towards the adoption of a regional Code of Conduct in the South China Sea(COC).Comply with the undertakings in the SEANFWZ Treaty, including accession to theInternational Atomic Energy Agency (IAEA) safeguards agreements and relatedinstruments;Encourage Accession to the Protocol of the SEANWFZ Treaty by Nuclear Weapon States; andCooperate to implement the Plan of Action and draw up specific work programmes/projects to implement the Plan of Action.Establish the ASEAN Maritime Forum;Apply a comprehensive approach that focuses on safety of navigation and securityconcern in the region that are of common concerns to the ASEAN Community;Stock take maritime issues and identify maritime cooperation among ASEAN membercountries; andPromote cooperation in maritime safety and search and rescue (SAR) through activitiessuch as information sharing, technological cooperation and exchange of visits ofauthorities concerned.i.ii.iii.iv.v.i.B. A Cohesive, Peaceful and Resilent Region with Shared Responsibility for Comprehensive Security17. In building a cohesive, peaceful and resilient Political Security Community, ASEAN subscribes to the principle of comprehensive security, which goes beyond the requirements of traditional security but also takes into account non-traditional aspects vital to regional and national resilience, such as the economic, socio-cultural, and environmental dimensions of development. ASEAN is also committed to conflict prevention/confidence building measures, preventive diplomacy, and post-conflict peace building.B.1. Conflict Prevention/Confidence Building Measures18. Confidence Building Measures and Preventive Diplomacy are important instruments in conflict prevention. They mitigate tensions and prevent disputes from arising between or among ASEAN Member States, as well as between ASEAN Member States and non-ASEAN member countries. They will also help prevent the escalation of existing disputes.19. In the area of defence and regional political consultations, ASEAN Defence Officials have been involved in the ASEAN security dialogue since 1996. Under the framework of the ASEAN Regional Forum (ARF), ASEAN has made voluntary briefings on political and security developments in the region and regularized meetings of high-level defence officials under the ARF Defence Officials’ Dialogue (DOD) and the ARF Security Policy Conference (ASPC). ASEAN has also established an annual ASEAN Defence Ministers Meeting (ADMM) and ASEAN Defence Senior Officials’ Meetings.B.1.1.Strengthen confidence-building measures Actions:B.1.2. Promote greater transparency and understanding of defence policies and security perceptionsActions:Organise regional exchanges among ASEAN Defense and military officials, at alllevels, including among military academies, staff colleges and defence universities inthe ASEAN Member States;Promote the exchange of observers of military exercises, commensurate with thecapability and condition of each ASEAN Member State;Share information among ASEAN Member States on submissions to the UN Register ofConventional Arms;Promote bilateral exchanges and cooperation between defence officials and exchangevisits between military training institutions to promote trust and mutual understanding;andConduct joint research projects on defence issues between government-affiliated policyand strategic research institutes in the region.ii.iii.iv.i.ii.iii.iv.v.vi.i.ii.iii.i.B.1.3. Build up the necessary institutional framework to strengthen the ARF process in support of the ASEAN Political-Security Community (APSC)Actions:B.1.4. Strengthen efforts in maintaining respect for territorial integrity, sovereignty and unity of ASEAN Member States as stipulated in the Declaration on Principles of International Law Concerning Friendly Relations and Cooperation among States in Accordance with the Charter of the United NationsActions:B.1.5. Promote the development of norms that enhance ASEAN defence and security cooperation Action:Work towards developing and publishing an annual ASEAN Security Outlook;Hold voluntary briefings on political and security developments in the region;Develop an ASEAN early warning system based on existing mechanisms to preventoccurrence/escalation of conflicts; andHold consultations and cooperation on regional defence and security matters betweenASEAN and external parties and Dialogue Partners including through the ADMM Pluswhen it is operationalised.Follow-up on the recommendations of the Review of the ARF;Implement the enhanced role of the ARF Chair, and activate the Friends of the ARFChair mechanism as and when needed;Implement the decision of the ARF Ministers to move the ARF towards the preventivediplomacy stage (PD);Expand the capacity of the ARF Heads of Defense Universities, Colleges and Institu-tions Meeting (ARF HDUCIM) to exchange best practices in defense policies and aca-demic development;Compile best practices on confidence building measures, preventive diplomacy andconflict resolutions for further development by ARF; andEnhance the role of the Secretary-General of ASEAN in the ARF including furtherstrengthening the ARF Unit in the ASEAN Secretariat.Compile best practices and relevant international law to promote understanding andappreciation of best practices concerning friendly relations and cooperation amongMember States of the United Nations;Convene consultation as well as a series of tract-two activities to strengthen cooperationin addressing threats and challenges that may affect the territorial integrity of ASEANMember States including those posed by separatism; andFurther promote and increase awareness on these issues to help accelerate the pace ofASEAN Community building and elevate ASEAN’s profile in the world.Initiate preparatory work for the development of practical cooperation programmesamong the militaries of ASEAN Member States.B.2. Conflict Resolution and Pacific Settlement of Disputes20. Convinced that the settlement of differences or disputes should be regulated by rational, effective and sufficiently flexible procedures, avoiding negative attitudes, which might endanger or hinder cooperation, ASEAN promotes the TAC, which seeks to preserve regional peace and harmony and prescribes that Member States refrain from threat or use of force.21. The TAC gives provision for pacific settlement of disputes at all times through friendly negotiations and for refraining from the threat or use of force to settle disputes. The strategies for conflict resolution shall be an integral part of a comprehensive approach. The purpose of these strategies shall be to prevent disputes and conflicts from arising between ASEAN Member States that could potentially pose a threat to regional peace and stability.22. ASEAN, the United Nations and other organisations have held a number of cooperation activities in the effort to promote peace and stability. More efforts are needed in strengthening the existing modes of pacific settlement of disputes to avoid or settle future disputes; and undertaking conflict management and conflict resolution research studies. Under the ASEAN Charter, ASEAN may also establish appropriate dispute settlement mechanisms.B.2.1.Build upon existing modes of pacific settlement of disputes and considerstrengthening them with additional mechanisms as needed Actions:B.2.2. Strengthen research activities on peace, conflict management and conflict resolution Actions:i.ii.iii.i.ii.iii.iv.v.vi.vii.Study and analyse existing dispute settlement modes and/or additional mechanismswith a view to enhancing regional mechanisms for the pacific settlement of disputes;Develop ASEAN modalities for good offices, conciliation and mediation; andEstablish appropriate dispute settlement mechanism, including arbitration as provid-ed for by the ASEAN Charter.Consider the establishment of an ASEAN Institute for Peace and Reconciliation;Compile ASEAN’s experiences and best practices on peace, conflict management andconflict resolution;Identify priority research topics, with a view to providing recommendations onpromoting peace, conflict management and conflict resolution;Enhance existing cooperation among ASEAN think tanks to study peace, conflictmanagement and conflict resolution;Hold workshops on peace, conflict management and conflict resolution with relevantregional and international organisations, including the UN;Undertake studies to promote gender mainstreaming in peace building, peace processand conflict resolution; andDevelop a pool of experts from ASEAN Member States as resource persons to assist inconflict management and conflict resolution activities.。

Branch and Bound ppt

Branch and Bound AlgorithmExhaustive Enumeration(完全枚举法)Knapsack problem (背包问题)where c i is the benefit obtained if item i is chosen, b is the amount of an available resource, and a i is the amount of the available resource used by item i.Exhaustive enumeration is also called Brute-force search.The number of possible solutions is 2n, where n is thenumber of variables.Exhaustive Search Tree•The circles are called nodes, and the lines are called branches. •At the very top of the tree, we have the root node.•As we descend the tree, decisions are made as indicated by the number on the branches.• A negative number, -j, implies that the variable xj has been setequal to 0, whereas a positive number +j, implies x j has been set equal to 1.At any node that is not a leaf, some variable, called the separation variable, is fixed at its two possible values at the next level.The set of solutions at the current node is divided into two mutually exclusive subsets by this operation.Choosing a separation variable and moving to the next level is called branching, because this is how the branches of the tree are formed.Branching strategy (i.e., choose a variable for branching) and search strategy (e.g., depth-first).Branch and Bound AlgorithmElementary but important observation:If you solve the LP relaxation of a pure IP and obtain a solution in which all variables are integers, then the optimal solution to the LP relaxation is also the optimal solution to the IP.The optimal solution to the LP relaxation of this pure IP isx1=0, x2=6, z=12.The feasible region for the IP is asubset of the points in the LPRelaxation’s feasible region.Assume the optimal solutions of IP andLP relaxation are ZIP and Z LP , so wemust have Z IP ≤ Z LP . (Maximizationproblem)•Z = ZLP•x 1=0, x 2=6 is a feasible integersolution, so Z ≤ ZIP .•Z ≤ Z IP ≤ Z LP =Z•So we must have Z = Z IPBranchFor an IP, we can gradually decompose it into a series of smaller IP problemsExample: If x1is a binary variable, then we may have two small problems, IP1and IP2:In IP1, fixing x1=0. Suppose Z IP1 is the optimal solution In IP2, fixing x1=1. Suppose Z IP2 is the optimal solution Z IP=max(Z IP1, Z IP2)BoundSuppose we have solved IP1 and got Z IP1Consider IP2:For the LP Relaxation of IP2, Z LP2can be obtainedIf Z LP2≤ Z IP1, we do not need to solve IP2Reason: Z IP2≤Z LP2≤ Z IP1, so Z IP1must be the optimalsolution to the original IPThis is called BOUNDFor each smaller IP, we can solve its LP relaxation and see if we can fathom it directly, meaning that we will no longerneed to solve itGeneral Approach of B&B Suppose we have a feasible solution of the IP at hand, the objective function value is z Bz B is a lower bound of the problemConsidering a small IP problem:Case 1: The LP relaxation has no feasible solutionThe IP has no feasible solution either.Case 2: In the LP relaxation, Z LP≤ Z BThe IP cannot have a better solution than Z B, thus can be fathomed Case 3: In the LP relaxation, an integer optimal solution is found, and Z LP> Z BThis small IP is solved, and update Z B=Z LPCase 4: In the LP relaxation, an optimal solution is found with Z LP> Z B, but not integer valueDecompose the IP into more smaller IP problems –more branchesWe call the LP relaxation of the original problemsubproblem 1.The optimal solution to the LP relaxation is z= 165/4,x1=15/4, x2=9/4.This implies that the optimal z-value for the IP cannotexceed 165/4.The optimal z-value for the LP relaxation is an upperbound for Telfa’s profit.Partitioning the feasible region for the LP relaxation.We arbitrarily choose avariable that is fractional in the optimal solution to the LPrelaxation—say x1.Every point in the feasible region for the IP must haveeither x1≤3 or x1≥4.Branch on the variable x1and create the following twoadditional subproblems:Subproblem2:Subproblem1 + Constraint x1≥ 4.Subproblem3:Subproblem1 + Constraint x1≤ 3.Branch and Bound TreeThe label t indicates thechronological order inwhich the subproblemsare solved.The optimal solution tosubproblem2 did not yield an integer solution, so we choose to use subproblem2 to createtwo new subproblems.We branch on x2by x2≥2 and x2≤1, which creates thefollowing two subproblems:Subproblem4:Subproblem1 + Constraints x1≥4and x2≥2 = subproblem2 +constraint x2≥2.Subproblem5:Subproblem1 + Constraint x1≥4 and x2≤1 = subproblem2+ constraint x2≤1.Subproblem 4 (or node 4) is fathomed since it is infeasible.The optimal solution to subproblem5 is point I:z=365/9, x1=40/9, x2=1.Partition subproblem5 by: Subproblem6:Subproblem5 + Constraint x1≥5Subproblem7:Subproblem5 + Constraint x1≤4subproblem 7 is pointH: z= 37, x1=4, x2=1,which is a feasiblesolution to the originalIP.Subproblem 7 has been fathomed.We may conclude that the optimal z-value forthe IP ≥37.37 is a lower bound onthe optimal z-value forthe original IP.•The optimal solution to the IP is for Telfa to manufacture 5 tables and 0 chairs.•This solution will contribute $40 to profits.B&B for Machine SchedulingFour jobs must be processed on a single machine.The time required to process each job and the date the job is due are shown in the following table.The delay of a job is the number of days after the due date thata job is completed (if a job is completed on time or early, thejob’s delay is zero).In what order should the jobs be processed to minimize the total delay of the four jobs?Suppose the jobs are processed in the following order: job 1, job 2, job 3, and job 4.Then the delays shown in the following table would occur. For this sequence, total delay = 0 + 6 + 3 + 7 = 16 days.Because a possible solution to the problem must specify the order in which the jobs are processed, we define:x ij= 1 if job i is the j-th job to be processed and =0 otherwise. The branch-and-bound approach begins by partitioning all solutions according to the job that is last processed.Any sequence of jobs must process some job last, so eachsequence of jobs must have x14=1, x24=1, x34=1, or x44=1.We branch on the node that has the smallest bound on D: node 4.Any job sequence associated with node 4 must have x13=1,x23=1, or x33=1.Branch on node 7Branch on node 3B&B for TSPJoe State lives in Gary, Indiana.He owns insurance agencies in Gary, Fort Wayne, Evansville, Terre Haute, and South Bend.Each December, he visits each of his insurance agencies.The distance between each agency (in miles) is shown in the following table.What order of visiting his agencies will minimize the total distance traveled?We might be able to find the answer to Joe’s problem by solving an assignment problem having a cost matrix whose ij-th element is c ij.For instance, suppose we solved this assignment problem and obtained the solution x12= x24=x45=x53x31=1.This solution can be written as 1 2 4 5 3 1. If the solution to the preceding assignment problem yields a tour, then it is the optimal solution to the traveling salesperson problem. (Why?)For example, the optimal solution to theassignment problem might be x15=x21=x34=x43x52=1.15342If we could exclude all feasible solutions that contain subtours and then solve the assignment problem, we would obtain the optimal solution to the traveling salesperson problem.The subproblems reduce to assignment problems.We first solve the assignment problem in the following table (referred to as subproblem 1).The optimal solution is x15=x21=x34=x43=x52=1, z=495. This solution contains two subtours (1-5-2-1 and 3-4-3) and cannot be the optimal solution to Joe’s problem.We branch on subproblem 1 in a way that will prevent one of subproblem 1’s subtours from recurring in solutions to subsequent subproblems. We choose to exclude the subtour 3 4 3.Observe that the optimal solution to Joe’s problem must have either x34=0 or x43=0.Thus, we can branch on subproblem 1 by adding the following two subproblems:Subproblem 2: Subproblem 1 + (x34= 0, or c34= M).Subproblem 3: Subproblem 1 + (x43=0, or c43= M).We arbitrarily choose subproblem 2 to solve, applying the Hungarian method to the cost matrix:The optimal solution to subproblem 2 is z = 652, x14=x25=x31=x43=x52=1.This solution includes the subtours 1 4 3 1 and 2 5 2, so this cannot be the optimal solution to Joe’s problem.We branch on subproblem 2 to exclude 2 5 2 by Subproblem 4: Subproblem 2 + (x25= 0, or c25= M).Subproblem 5: Subproblem 2 + (x52= 0, or c52= M).We solve subproblem 4 & 5Only subproblem 3 remains.We find the optimal solution to the assignment problem in the following table, x13=x25=x34=x52=1, z=652.We branch on subproblem 3 to exclude the subtour. Any feasible solution to the traveling salesperson problem that emanate from subproblem 3 must haveeither x25=0 or x52=0(why?).Subproblem 6: Subproblem 3 + (x25= 0, or c25= M).Subproblem 7: Subproblem 3 + (x52= 0, or c52= M).1-TreeDefinition: for a given vertex, say vertex 1, a 1-Tree is a tree of {2,3,…,n}+2 distinct edges connected to vertex 1.Example of 1-TreeMinimum weight 1-Tree: Min cost 1-tree of all possible 1-Trees.To find minimum weight 1-Tree, first find minimum spanning tree of {2,3,…,n} vertices, and add two lowest cost edges incident to vertex 1.Any TSP tour is 1-Tree tour (with arbitrary starting node 1) in which each vertex has a degree of 2.If minimum weight 1-Tree is a tour, it is the optimal TSP tour.Thus, the minimum 1-Tree provides a lower bound on the length of the optimal TSP tour.How do we branch?Observe that in the case our 1-tree is not a tour at least one vertex has degree 3 or more.So choose a vertex v with degree 3 or more.For each edge (u i, v) generate a subproblem where (u i, v) is excluded from the set of edges.For each vehicle, the total assigned demand cannot exceed Q.Each route must start from and end at the depot.Each vertex is visited exactly once.All customer demands are satisfied.The Single Vehicle Routing Problem with Toll-by-weight Scheme: ABranch-and-bound Approach(SVRPTBW)湖北省高速车辆计重收费基本费率0.08元/吨.公里正常装载部分正常装载部分≤10吨基本费率10吨＜正常装载部分≤40吨从基本费率线性递减到基本费率的一半正常装载部分>40吨基本费率的一半超限装载部分超限率≤30% 按其正常装载部分的费率计费30%<超限率≤100% 正常装载部分和超限30％以内（含30%）的部分按其正常装载部分的费率计费，其他部分按基本费率的1-4倍线性递增确定费率计费。

On the Spontaneous CP Breaking in the Higgs Sector of the Minimal Supersymmetric Standard M

b
g b Vb −
f
where gb (gf ) denotes the number of degrees of freedom of bosons (fermions). In the bosonic part we sum over stops, neutral scalar and charged Higgses, and Goldstone bosons (b = ˜L,R , h, H, H ± , G± ), and in the fermionic one we consider neutralinos and charginos (f = t χ ˜o , χ ˜± ). Working in the ’t Hooft–Landau gauge and in the DR renormalization scheme, we will decompose the bosonic components as
2 2 (2) m2 3 − λ6 v1 − λ7 v2 < 1. 4λ5 v1 v2 In the MSSM these conditions are not satisﬁed (at tree level) because in this case supersymmetry gives 1 (g 2 + g ′ 2 ), λ1 = λ2 = 8
J.R. Espinosa †, J.M. Moreno and M. Quir´ os Instituto de Estructura de la Materia, CSIC Serrano 123, E–28006 Madrid, Spain
Abstract We revise a recently proposed mechanism for spontaneous CP breaking at ﬁnite temperature in the Higgs sector of the Minimal Supersymmetric Standard Model, based on the contribution of squarks, charginos and neutralinos to the one-loop eﬀective potential. We have included plasma eﬀects for all bosons and added the contribution of neutral scalar and charged Higgses. While the former have little eﬀect, the latter provides very strong extra constraints on the parameter space and change drastically the previous results. We ﬁnd that CP can be spontaneously broken at the critical temperature of the electroweak phase transition without any ﬁne-tuning in the parameter space.

legislative Branch in America

Each year, the entire Congress holds an annual meeting on January 3 (which was mandated when the 20th amendment was passed in 1933. The President can also call an extra session of Congress, or of either house)
House of Representatives comprises lawmakers who serve two-year terms Each state is a district and a count ofቤተ መጻሕፍቲ ባይዱthe population is taken every 10 years.
The senators help create and pass laws, and also interview candidates that the president elects for certain offices (such as Supreme Court justices). It can also ratify treaties the president makes (with a 2/3 majority )
Members of the House of Representatives were always elected by popular vote, but until 1913, Senators were chosen by state legislatures. This changed when the 17th amendment passed which determined that senators would be chosen by popular vote .

checks and balances

•
EXECUTIVE BRANCH
• The president’s cabinet (13 department) : State , Treasury , Defense , Justice , Interior , Agriculture , Commerce , Labor , Health and Human Services , Housing and Urban Development , Transportation , Energy and Education .
A bill
Pass different versions The Senate or House chamber of the same bill
Lobbies
Both House of Congress Sent to the president pass a bill A law Signed
CHECKS & BALANCES
•
Checks and Balances are Legislative Branch , Executive Branch and Judicial Branch
LEGISLATIVE BRANCH
• The legislative branch is made up of elected representatives from all the states and is the only branch that can make federal laws ,levy federal taxes , declare war or put foreign treaties into effect .
The Supreme Court

survey for the quadratic assignment problem

Invited ReviewA survey for the quadratic assignment problem qEliane Maria Loiola a ,Nair Maria Maia de Abreu a ,Paulo Oswaldo Boaventura-Netto a ,Peter Hahn b,*,Tania Queridoc,1aFederal University of Rio de Janeiro,Brazil b Department of Electrical and Systems Engineering,University of Pennsylvania,2127Tryon Street,Philadelphia,PA 19146-1228,United Statesc Federal Center for Technological Education,BrazilReceived 13September 2004;accepted 2September 2005Available online 27December 2005AbstractThe quadratic assignment problem (QAP),one of the most diﬃcult problems in the NP-hard class,models many real-life problems in several areas such as facilities location,parallel and distributed computing,and combinatorial data binatorial optimization problems,such as the traveling salesman problem,maximal clique and graph par-titioning can be formulated as a QAP.In this paper,we present some of the most important QAP formulations and classify them according to their mathematical sources.We also present a discussion on the theoretical resources used to deﬁne lower bounds for exact and heuristic algorithms.We then give a detailed discussion of the progress made in both exact and heuristic solution methods,including those formulated according to metaheuristic strategies.Finally,we analyze the contributions brought about by the study of diﬀerent approaches.Ó2005Elsevier B.V.All rights reserved.Keywords:Assignment;Integer programming;Combinatorial optimization;Facilities planning and design;Metaheuristics;Branch and bound1.IntroductionLet us consider the problem of assigning facilities to locations in such a way that each facility is designated to exactly one location and vice-versa.The distances between locations,the demand ﬂows 0377-2217/$-see front matter Ó2005Elsevier B.V.All rights reserved.doi:10.1016/j.ejor.2005.09.032qA preliminary version of this survey,with 278references,is Loiola et al.(2004).*Corresponding author.E-mail addresses:eliane@pep.ufrj.br (E.M.Loiola),nair@pep.ufrj.br (N.M.M.de Abreu),boaventu@pep.ufrj.br (P.O.Boaventura-Netto),hahn@ (P.Hahn),tania.querido@ (T.Querido).1Present address:University of Florida,Gainesville,supported by CNPq,Brazil.European Journal of Operational Research 176(2007)657–690/locate/ejor658 E.M.Loiola et al./European Journal of Operational Research176(2007)657–690among the facilities and,in the general case,the facility versus location assignment costs are known.The international literature identiﬁes the quadratic assignment problem(QAP)as the problem ofﬁnding a min-imum cost allocation of facilities into locations,taking the costs as the sum of all possible distance-ﬂow products.The main motivation for this survey is the continuous interest in QAP,shown by a number of research-ers worldwide,for the theory,applications and solution techniques for this problem.Among the many ref-erences listed at the end of this paper,we found over100that were published since1999.The last surveys, books and review articles in the literature are Burkard(1991),Malucelli(1993),Pardalos et al.(1994),Bur-kard and C¸ela(1996),C¸ela(1998)and Burkard et al.(1998a).The article of Anstreicher(2003)reviews only the recent advances on algorithms.An article by Drezner et al.(in press)surveys the state-of-the-art in both heuristic and exact methods.Koopmans and Beckmann(1957)ﬁrst proposed the QAP as a mathematical model related to economic activities.Since then,it has appeared in several practical applications:Steinberg(1961)used the QAP to minimize the number of connections between components in a backboard wiring;Heﬄey(1972,1980) applied it to economic problems;Francis and White(1974)developed a decision framework for assigning a new facility(police posts,supermarkets,schools)in order to serve a given set of clients;Geoﬀrion and Graves(1976)focused on scheduling problems;Pollatschek et al.(1976)invoked the QAP to deﬁne the best design for typewriter keyboards and control panels;Krarup and Pruzan(1978)applied it to archeology; Hubert(1987)in statistical analysis;Forsberg et al.(1994)used it in the analysis of reaction chemistry and Brusco and Stahl(2000)in numerical analysis.Nevertheless,the facilities layout problem is the most popular application for the QAP:Dickey and Hopkins(1972)applied the QAP to the assignment of build-ings in a University campus,Elshafei(1977)in a hospital planning and Bos(1993)in a problem related to forest parks.Benjaafar(2002)introduced a formulation of the facility layout design problem in order to minimize work-in-process(WIP).In his work,he shows that layouts obtained using a WIP-based formu-lation can be very diﬀerent from those obtained using the conventional QAP-formulation.For example,a QAP-optimal layout can be WIP-infeasible.Rabak and Sichman(2003),Miranda et al.(2005)and Duman and Ilhan(in press)studied the placement of electronic components.The index assignment problem(Ben-David and Malah,2005)has to do with error control in communi-cations and can be shown to be a special case of the QAP.Wess and Zeitlhofer(2004)studied the problem of memory layout optimization in signal processors.Other applications can be found in Scriabin and Ver-gin(1975),Hubert and Schulz(1976),Heﬄey(1977),Los(1978),Khare et al.(1988a,b),Krackhardt(1988), Bland and Dawson(1991),Balakrishnan et al.(1992),Lacksonen and Enscore(1993),Medova(1994),Phil-lips and Rosen(1994),Gouveia and Voß(1995),Bozer and Suk-Chul(1996),Talbot and Cawley(1996), White(1996),Mason and Ro¨nnqvist(1997),Ostrowski and Ruoppila(1997),Ball et al.(1998),Haghani and Chen(1998),Kochhar et al.(1998),Martin(1998),Sarker et al.(1998),Spiliopoulos and Soﬁanopou-lou(1998),Tansel and Bilen(1998),Tavakkoli-Moghaddain and Shayan(1998),Urban(1998),Gong et al. (1999),Rossin et al.(1999),Bartolomei-Suarez and Egbelu(2000),Ho and Moodie(2000),Urban et al. (2000),Hahn and Krarup(2001),Pitsoulis et al.(2001),Takagi(2001),Siu and Chang(2002),Wang and Sarker(2002),Youssef et al.(2003),Yu and Sarker(2003),Ciriani et al.(2004),Solimanpur et al. (2004)and Abbiw-Jackson et al.(in press).Since itsﬁrst formulation,the QAP has been drawing researchers’attention worldwide,not only because of its practical and theoretical importance,but also because of its complexity.The QAP is one of the most diﬃcult combinatorial optimization problems.In general,instances of size n>30cannot be solved in rea-sonable time.Sahni and Gonzales(1976)had shown that QAP is NP-hard and that,unless P=NP,it is not possible toﬁnd an f-approximation algorithm,for a constant f.Such results are valid even whenﬂows and distances appear as symmetric coeﬃcient matrices.Due to its high computation complexity,the QAP has been chosen as theﬁrst major test application for the GRIBB project(great international branch-and-bound search).This project is seeking to establish a software library for solving a large class of parallelE.M.Loiola et al./European Journal of Operational Research176(2007)657–690659 search problems by the use of numerous computers around the world accessed by Internet.Preliminary results from test runs are presented in Moe(2003).Several NP-hard combinatorial optimization problems,such as the traveling salesman problem,the bin-packing problem and the max clique problem,can be modeled as QAPs.The search for local optima in classical internet-available instances is a tendency that allows for the comparison of technique perfor-mances,even when the optimum is unknown,or when the use of exact algorithms in these instances is pos-sible,Burkard et al.(1996a,1998b)and C¸ela(1998)).In the QAP case,we can mention as examples, instances with recently proved optimal solutions:Bur26(b to h),(2004)and Tai25a(2003)by Hahn;Ste36a (2001)by Brixius and Anstreicher;Bur26a(2001)by Hahn;Kra30a by Hahn;Kra30b,Kra32and Tho30 (2000)by Anstreicher,Brixius,Goux and Linderoth;Nug30(one of the most renowned and challenging instances)(2000)by Anstreicher,Brixius,Goux and Linderoth;Ste36b and Ste36c(1999)by Nystro˜m. In2003,Misevicius enhanced the best-known solution for Tai50a,Tai80a and Tai100a using a modiﬁed tabu search.Those results motivated the article of Anstreicher(2003)that registers the recent advances in QAP-solutions and describes the new algorithms and computational structures used.Besides,the new instances are available for tests in Burkard et al.(1991,1997),Li and Pardalos(1992)and QAPLIB (2004).Also,there are instance generators with known optimum values that are currently used for testing algorithms,C¸ela(1998).Finally,Palubeckis(1999,2000),Drezner et al.(in press)and Stu¨tzle and Fernan-des(2004)present new instance sets that are reported to be diﬃcult for metaheuristics.Experts in combinatorial optimization tend to search for particular polynomially solvable versions of NP-hard problems and research mechanisms to measure the diﬃculty of problem instances.In the case of the QAP,Christoﬁdes and Gerrard(1981)studied some special instances of the QAP;Sylla and Babu (1987)developed a methodology for an orderly quadratic assignment problem;Chen(1995)presented other QAP-cases,followed by C¸ela(1998),who presented several polynomially solvable instances;Herroeleven and Vangils(1985),Cyganski et al.(1994),Mautor and Roucairol(1994b)showed that Palubetski’s QAP instances are degenerate;Angel and Zissimopoulos(1998,2000,2001,2002)discussed the diﬃculty of other QAP instances based on the variance of theirﬂow and distance sets;Abreu et al.(2002)derived a polynomial expression for the variance of the solution costs and deﬁned a measure of the diﬃculty instances and Barvinok and Stephen(2003)constructed a distribution of QAP solution-values.In the challenge of identifying new structural properties for QAP instances,many formulations have appeared,based on various points of view.Here we propose to collect these formulations,highlighting their most important features,and to classify them according to the technique used,such as integer program-ming,positive semi-deﬁnite programming,discrete and combinatorial mathematics,graph and group the-ory,or linear algebra via spectral theory.Most of these formulations are equivalent,except for those that characterize more general problems.Considering the diﬃculty of the QAP,these formulations encourage addition of mathematical resources for the development of new solution techniques.By the end of this arti-cle,we discuss the contributions obtained from these formulations,building several tables and charts from the extensive bibliography concerning the elaboration of exact and heuristic algorithms,lower bound cal-culation,instance class characteristics and recording the development of QAP since1957to the present.The following surveys are essential references for those who want to have a more complete understand-ing of this problem:Hanan and Kurtzberg(1972),Burkard(1984,1991,2002),Pardalos et al.(1994)and Burkard et al.(1998a),as well as,the books by Pardalos and Wolkowicz(1994),Padberg and Rijal(1996), Dell’Amico et al.(1997)and C¸ela(1998).2.Formulations of QAP and related problemsIn this section,we present the most important QAP formulations and describe the type of solution approach adopted for each formulation.2.1.Selected QAP formulations2.1.1.Integer linear programming formulations(IP)First,we present the QAP as a Boolean program followed by a linear programming problem,where the binary constraints are relaxed.The Boolean formulation was initially proposed by Koopmans and Beck-mann(1957)and later used in several works such as Steinberg(1961),Lawler(1963),Gavett and Plyter (1966),Elshafei(1977),Bazaraa and Sherali(1979),Bazaraa and Kirca(1983),Christoﬁdes and Benavent (1989),Bos(1993),Mans et al.(1995),Ju¨nger and Kaibel(2000,2001a,b),Liang(1996),Torki et al.(1996), Tsuchiya et al.(1996,2001),Ball et al.(1998),Ishii and Sato(1998),Kaibel(1998),Kochhar et al.(1998), Martin(1998),Spiliopoulos and Soﬁanopoulou(1998),and most recently,Siu and Chang(2002),Yu and Sarker(2003)and,ﬁnally,Fedjki and Duﬀuaa(2004).We consider f ij theﬂow between facilities i and j,and d kp the distance between locations k and p.It is our goal to calculate:minX ni;j¼1X nk;p¼1f ij d kp x ik x jpð2:1Þs.t.X ni¼1x ij¼116j6n;ð2:2ÞX nj¼1x ij¼116i6n;ð2:3Þx ij2f0;1g16i;j6n.ð2:4ÞIf we consider the cost of assignment of activities to locations,a general form for a QAP instance of order n is given by three matrices F=[f ij],D=[d kp]and B=[b ik],theﬁrst two matrices deﬁning theﬂows between facilities and the distances between locations,b ik being the allocation costs of facilities to locations.This problem can be deﬁned as:minX ni;j¼1X nk;p¼1f ij d kp x ik x jpþX ni;k¼1b ik x ikð2:5Þs.t.(2.2),(2.3)and(2.4).Since the linear term of(2.5)is easy to solve,most authors discarded it.A more general QAP version was proposed by Lawler(1963)and involves costs c ijkp that do not neces-sarily correspond to products ofﬂows and distances.The Lawler formulation is as follows:minX ni;j¼1X nk;p¼1c ijkp x ik x jpð2:6Þs.t.(2.2),(2.3)and(2.4).This model was also used in Bazaraa and Elshafei(1979),Drezner(1995),Sarker et al.(1995,1998),Bru¨ng-ger et al.(1997,1998),Chiang and Chiang(1998),Hahn and Grant(1998),Hahn et al.(1998),Gong et al. (1999)and Rossin et al.(1999).2.1.2.Mixed integer linear programming(MILP)formulationsThe QAP,as a mixed integer programming formulation,is found in the literature in diﬀerent forms.All of them replace the quadratic terms by linear terms.For example,Lawler(1963)used n4variables,c ijkp¼f ijd kp and y ijkp¼x ik x jp;16i;j;k;p6n.660 E.M.Loiola et al./European Journal of Operational Research176(2007)657–690Other formulations use relaxations of the original problem.In this category,one canﬁnd the papers by Love and Wong(1976a,b),Kaufman and Broeckx(1978),Bazaraa and Sherali(1980),Christoﬁdes et al. (1980),Burkard and Bonniger(1983),Frieze and Yadegar(1983),Assad and Xu(1985),Adams and Sherali (1986),Christoﬁdes and Benavent(1989)and the works of Adams and Johnson(1994),Drezner(1995), Gouveia and Voß(1995),Milis and Magirou(1995),Padberg and Rijal(1996),White(1996),Ramachan-dran and Pekny(1998),Karisch et al.(1999)and of Ramakrishnan et al.(2002).In general,QAP linearizations based on MILP models present a huge number of variables and con-straints,a fact that makes this approach unpopular.However,these linearizations,together with some con-straint relaxations,lead to the achievement of much improved lower bounds for the optimal solution.In this regard,we have the works of Kaufman and Broeckx(1978),Bazaraa and Sherali(1980),Frieze and Yadegar(1983),Adams and Sherali(1986),Adams and Johnson(1994)and Padberg and Rijal(1996).C¸ela (1998)mentions three QAP linearizations:Kaufman and Broeckx(1978),which has the advantage of a smaller number of restrictions;Frieze and Yadegar(1983),for achieving the best lower bounds via Lagran-gean relaxation and Padberg and Rijal(1996)owing to its polytope description.The formulation presented by Frieze and Yadegar(1983)describes the QAP in a linear form,using n4real variables,n2Boolean vari-ables and n4+4n3+n2+2n constraints.The authors show that the formulation given in(2.7)–(2.16) below is equivalent to Eqs.(2.1)–(2.4),C¸ela(1998).minX ni;j¼1X nk;p¼1f ij d kpÁy ijkpð2:7Þs.t.X ni¼1x ik¼116k6n;ð2:8ÞX nk¼1x ik¼116i6n;ð2:9ÞX n i¼1yijkp¼x jp16j;k;p6n;ð2:10ÞX n j¼1yijkp¼x ik16i;k;p6n;ð2:11ÞX n k¼1yijkp¼x jp16i;j;p6n;ð2:12ÞX n p¼1yijkp¼x ik16i;j;k6n;ð2:13Þyiikk¼x iik16i;k6n;ð2:14Þx ik2f0;1g16i;k6n;ð2:15Þ06yijkp6116i;j;k;p6n.ð2:16Þ2.1.3.Formulations by permutationsTaking a simple approach,the pairwise allocation of facility costs to adjacent locations is proportional toﬂows and to distances between them.The QAP formulation that arises from this proportionality and uses the permutation concept can be found in Hillier and Michael(1966),Graves and Whinston(1970), Pierce and Crowston(1971),Burkard and Stratman(1978),Roucairol(1979,1987),Burkard(1984),Frenk et al.(1985),Bland and Dawson(1991,1994),Battiti and Tecchiolli(1994),Bui and Moon(1994),Chakra-pani and Skorin-Kapov(1994),Fleurent and Ferland(1994),Li et al.(1994b),Mautor and RoucairolE.M.Loiola et al./European Journal of Operational Research176(2007)657–690661(1994a,b),Li and Smith(1995),Taillard(1995),Bozer and Suk-Chul(1996),Colorni et al.(1996),Huntley and Brown(1996),Peng et al.(1996),Tian et al.(1996,1999),Cung et al.(1997),Mavridou and Pardalos (1997),Merz and Freisleben(1997),Nissen(1997),Pardalos et al.(1997),Angel and Zissimopoulos(1998), Deineko and Woeginger(1998),Talbi et al.(1998a,b,2001),Tansel and Bilen(1998),Abreu et al.(1999), Fleurent and Glover(1999),Gambardella et al.(1999)and Maniezzo and Colorni(1999).More recently, the following articles were released:Ahuja et al.(2000),Angel and Zissimopoulos(2000,2001,2002),Stu¨t-zle and Holger(2000),Arkin et al.(2001),Pitsoulis et al.(2001),Abreu et al.(2002),Gutin and Yeo(2002), Hasegawa et al.(2002),Boaventura-Netto(2003)and Rangel and Abreu(2003).Costa and Boaventura-Netto(1994)studied the non-symmetrical QAP through a directed graph formulation.Let S n be the set of all permutations with n elements and p2S n.Consider f ij theﬂows between facilities i and j and d p(i)p(j)the distances between locations p(i)and p(j).If each permutation p represents an alloca-tion of facilities to locations,the problem expression becomes:min p2S n X ni;j¼1f ij d pðiÞpðjÞ.ð2:17ÞThis formulation is equivalent to theﬁrst one presented in(2.1)–(2.4),since the constraints(2.2)and(2.3) deﬁne permutation matrices X=[x ij]related to S n elements,as in(2.17),where,for all16i,j6n,x ij¼1;if pðiÞ¼j;0;if pðiÞ¼j.ð2:18Þ2.1.4.Trace formulationThis formulation is supported by linear algebra and exploits the trace function(the sum of the matrix main diagonal elements)in order to determine QAP lower bounds for the cost.This approach allows for the application of spectral theory,which makes possible the use of semi-deﬁnite programming to the QAP.The trace formulation,by Edwards(1980),can be stated as:minX2S ntrðFÁXÁDÁX tÞ.ð2:19ÞAfterwards,this approach was used in several works:Finke et al.(1987),Hadley et al.(1990,1992a,b,c), Hadley(1994),Karisch et al.(1994),Karisch and Rendl(1995),Zhao et al.(1998),Anstreicher et al. (1999),Wolkowicz(2000a,b)and Anstreicher and Brixius(2001).The following formulations deﬁne QAP relaxations through the dual of the Lagrangean dual,as weﬁnd in Karisch et al.(1994),Zhao et al.(1998),Wolkowicz(2000a,b).Let e be a vector with each coordinate equal to1.If X is a permutation matrix and B is a cost matrix,then the SDP formulation is: min trðFÁXÁDÀ2BÞX tð2:20Þs.t.Xe¼e;ð2:21ÞX t e¼e;ð2:22ÞX ij2f0;1g8i;j.ð2:23ÞAnother formulation that follows this approach,Zhao et al.(1998),ismin tr FÁXÁDÁX tÀ2BX tð2:24Þs.t.XX t¼X t X¼I;ð2:25ÞXe¼X t e¼e;ð2:26ÞX2ij ÀX ij¼08i;j.ð2:27Þ662 E.M.Loiola et al./European Journal of Operational Research176(2007)657–690From the formulations(2.20)–(2.23)and(2.24)–(2.27)one can derive semi-deﬁnite relaxations for the QAP. Roupin(2004)presents a simple algorithm to obtain SDP relaxations for any quadratic or linear program with bivalent variables,starting from an existing linear relaxation of the considered combinatorial problem. This algorithm is applied to obtain semi-deﬁnite relaxations for three classical combinatorial problems:the k-Cluster Problem,the Quadratic Assignment Problem,and the Constrained-Memory Allocation Problem.2.1.5.Graph formulationLet us consider two undirected weighted complete graphs,theﬁrst one having its edges associated to ﬂows and the second one,to distances.The QAP can be thought as the problem ofﬁnding an optimal allo-cation of the vertices of one graph on those of the other.In this formulation the solution costs are given as the sum of products of corresponding edge weights(see Fig.1).The algebraic and combinatorial approach adopted by Abreu et al.(1999)was the impetus for Marins et al.(2004)to deﬁne a new algebraic graph–theoretical approach involving line-graph automorphisms.The line-graph of a given graph G,denoted L(G),is determined by taking each edges of G as a vertex of L(G), while an edge of L(G)is deﬁned as a pair of edges that are adjacent in G.A graph automorphism is a per-mutation of its vertices that preserves the edges.The set of all automorphisms of G together with the per-mutations composition is a group denoted by Aut(L(G))(Kreher and Stinson(1998)).From a theorem by Whitney(1932),if G=K n,n52and4,then Aut(G)and Aut(L(G))constitute iso-morphic groups.Based on this result,Marins et al.(2004)noticed that solving the QAP means eitherﬁnd-ing a permutation p2S n orﬁnding a L(K n)automorphism,which is a C n,2permutation,that minimizes the following expression:minp2AutðLðK nÞÞX Ni¼1f i d pðiÞ.ð2:28ÞIt is appropriate to mention White(1995),wherein a number of QAP representations are discussed with respect to their convexity and concavity and also Yamada(1992),where a formulation is presented for the QAP on an n-dimensional grid.2.2.QAP related problemsThe most classical QAP-related problem is,obviously,the Linear Assignment Problem(LAP),which is polynomial and easily solved by the Hungarian method.As several presentations of this problem can be found in the literature(for example,Burkard,2002),we do not discuss the LAP here.We prefer to begin with another linear problem also used in QAP studies.The three-index assignment problem(3-dimensional AP or3AP),ﬁrst suggested by Pierskalla(1967a,b, 1968),searches for two permutations p and u2S n,so that the following expression is minimized:min p;u2S n X ni¼1c i pðiÞuðiÞ.ð2:29ÞFig.1.Allocation of cliques K F over K D concerning permutation p=(4,2,1,3).E.M.Loiola et al./European Journal of Operational Research176(2007)657–690663Burkard and Fro¨hlich(1980)proposed a branch-and-bound algorithm to solve the3AP.Emelichev et al. (1984)described transportation models with multiple indices,with details,based on this formulation.The 3-dimensional AP has been studied by several QAP experts:Vlach(1967),Frieze(1974,1983),Frieze and Yadegar(1981),Burkard et al.(1986,1996a,b),Euler(1987),Balas and Saltzman(1989,1991),Bandelt et al.(1991),Crama and Spieksma(1992),Balas and Qi(1993),Burkard and Rudolf(1993),Qi et al. (1994),Magos and Miliotis(1994),Poore(1994a,b,1995),Burkard and C¸ela(1996),Magos(1996),Poore and Robertson(1997)and Burkard(2002).A wide range of QAP theoretical studies involve several related quadratic problems,such as the qua-dratic bottleneck assignment problem,the biquadratic assignment problem,the3-dimensional QAP,the quadratic semi-assignment problem and the multiobjective QAP.Almost all of these problems were reported in Burkard(2002).2.2.1.The quadratic bottleneck assignment problem(QBAP)Steinberg(1961)considered QBAP a variation of QAP with applications to backboard wiring.In that work,a placement algorithm was presented for the optimal connection of n elements in individual locations so that the length wire needed to connect two elements is minimized.The basic claim of the paper is:the opti-mal weighted-wire-length equals the least among the maximum-wire-length norms.This concept arises from the principle that it may be better to minimize the largest cost in a problem,than to minimize the overall cost.The QBAP general program is obtained from the QAP formulation by substituting the maximum oper-ation in the objective function for the sums,which suggests the term bottleneck function: minp2S nmax f f ij d pðiÞpðjÞ:16i;j6n g.ð2:30ÞA general formulation related to(2.30)was studied in Burkard and Finke(1982),Burkard and Zimmer-mann(1982),Kellerer and Wirsching(1998)and Burkard(2002).2.2.2.The biquadratic assignment problem(BiQAP)Proposed by Burkard et al.(1994),this problem can be found in other works,such as Burkard and C¸ela (1995),Mavridou et al.(1998)and Burkard(2002).Theﬂow and distance matrices are order n4and the BiQAP-formulation is:min p2S nX ni;j;k;l¼1f ijkl d pðiÞpðjÞpðkÞpðlÞ.ð2:31Þ2.2.3.The quadratic3-dimensional assignment problem(Q3AP)Pierskalla(1967b)introduced it in a technical memorandum.The work was never published in the open literature.Since then,nothing on the subject has been found in the publication databases.Hahn et al.(2004) re-discovered the Q3AP while working with others on a problem arising in data transmission system design. The purpose of the work is to jointly optimize pairs of mappings for multiple transmissions using higher order signal constellations.The resulting problem formulation is:minP Ni¼1P Nj¼1P Np¼1b ijp u ij w ipþP Ni¼1P Nj¼1P Np¼1P Nk¼1P Nn¼1P Nq¼1ÂC ijpknq u ij u kn w ip w kq:u2X;w2X;u;w binary8><>:9>=>;;ð2:32Þwherex2X x P0:X Ni¼1x ij¼1for j¼1;...;N;X Nj¼1‘x ij¼1for i¼1;...;N().ð2:33Þ664 E.M.Loiola et al./European Journal of Operational Research176(2007)657–6902.2.4.The quadratic semi-assignment problem(QSAP)This is a special case used to model clustering and partitioning problems by Hansen and Lih(1992).It can be written as:minX mk¼1X ni;j¼1c ij x ik x jkð2:34Þs.t.X mk¼1x ik¼116i6n;ð2:35Þx ij2f0;1g16i;j6n.ð2:36ÞOther applications can be found in Simeone(1986a,b)and Bullnheimer(1998).References for polynomial heuristics and lower bounds are found in Freeman et al.(1966),Magirou and Milis(1989),Carraresi and Malucelli(1994)and Billionnet and Elloumi(2001).Samra et al.(2005)presented a simple,but eﬀective method of enhancing and exploiting diversity from multiple packet transmissions in systems that employ non-binary linear modulations such as phase-shift keying(PSK)and quadrature amplitude modulation (QAM).The optimal adaptation scheme reduces to solving the general form of the QAP,wherein the prob-lem costs cannot be expressed as products ofﬂows and distances(see Eq.(2.6),above).2.2.5.The multiobjective QAP(mQAP)Knowles and Corne(2002)presented another QAP variation considering severalﬂow and distance matrices.This problem is a benchmark case for multiobjective metaheuristics or multiobjective evolutionary algorithms.According to the authors,this model is more suitable for some layout problems,such as the allocation of facilities in hospitals,where it is desired to minimize the products of theﬂows by the distances between doctors and patients,and between nurses and medical equipment simultaneously.The mathemat-ical expression is then,minp2S n~CðpÞ¼f C1ðpÞ;C2ðpÞ;...;C mðpÞg;where C kðpÞ¼X ni;j¼1f kijd pðiÞpðjÞ;16k6m:ð2:37ÞIn this last constraint,f kij denotes the k thﬂow between i-and j-facilities.More recently,Knowles and Corne(2003)presented instance generators for the multiobjective version of QAP.Lopez-Ibanez et al.(2004)dis-cuss the design of ACO algorithms.Paquete and Stu¨tzle(2004)developed a study of stochastic local search algorithms for the biobjective QAP with diﬀerent degrees of correlation between theﬂow matrices.Kle-eman et al.(2004)analyze a parallel technique and Day and Lamont(2005)present a speciﬁc algorithm.A combination QAP queuing model is discussed by Smith and Li(2001),in the context of traﬃc networks.3.Lower boundsThe study of lower bounds is very important for the development of algorithms to solve mathematical programming and combinatorial optimization problems.Generally,the exact methods employ implicit enumeration,in an attempt to guarantee the optimum and,at the same time,to avoid the total enumeration of the feasible solutions.The performance of these methods depends on the computational quality and eﬃ-ciency of the lower bounds.E.M.Loiola et al./European Journal of Operational Research176(2007)657–690665。

acca F4 背诵讲义

Chapter 1 Structure of the legal system1. ESSENTIAL ELEMENTS OF THE LEGAL SYSTEMLaw•Law is a formal control mechanism.•It provides a structure for dealing with and resolving disputes.•It also provides some deterrent to those wishing to disrupt social order.Common law•Common law developed in England during the period following the Norman Conquest.•It was made by judges who travelled around the country to keep the King’s peace and made law by merging local customary laws into one ‘law of the land’.•Today, the concept of PRECEDENT continues to be the key feature of commom law, and distinguishes it from other legal systems.•Remedies under common law are monetary, and are known as damages.Equity•Common law does not provide justice to the wronged person if monetary compensation is not suitable.•Equity developed two or three hundred years after common law as a system to resolve disputes where damages are not a suitable remedy and therefore introduced fairnessinto the legal system.•For example, where a person needs to stop another person’s behaviour or to force them to act as they agreed to, equity provides remedies to achieve this.Civil law•Civil law exists to resolve disputes over the rights and obligations of persons dealing with each other and seeks to compensate wronged parties.•It is a form of private law (between individuals) and covers areas such as tort, contract and employment law.•In civil proceedings, the case must be proved on the balance of probability, the object is to convince the court that it is probable that a person’s assertions are ture.•There is no concept of punishment in the civil law and compensation is paid to the wronged person.•If they wish, both parties may choose to settle the dispute out of court.Criminal law• A crime is conduct that is prohibited by the law.•Criminal law is a form of public law (betweent the State and individuals).•In criminal proceedings, the State is the procecutor because it is the community as a whole which suffers as a result of the law being broken.•The burden of proof to convict the accused(认定被告有罪) rests with the procecution, which must prove its case beyond reasonble doubt.•In the UK, the police take the initial decision to prosecute, this is then reviewed by the Crown Prosecution Service. However, some prosecutions are started by the Director of Public Prosecutions, who is the head of the Crown Prosecution Service.•Persons guilty of crime may be punished by fines payable to the State, imprisonment, ora community-based punishment.The distinction between civil law and criminal lawThis is not an act or event which creates the distinction between civil and criminal law, but the legal consequences. A single event might give rise to both civil and criminal proceedings.2. JURISDICTION OF CIVIL COURTS•The nature of the case and the size of the claim will determine which court hears a civil case.•The County courts hear small cases ( claims under £5,000) or those which are deemed to be ‘FAST TRACK’ cases. The case is heard by a Circuit Judg e assisted by DistrictJudges.•Complicated cases or those which are deemed to be ‘MULTI TRACK’ cases are heard at the High Court.•The Queen’s Bench Division hears cases concerning contract and tort issues.•The Family Division hears cases concerning children and matrimonial issues.•The Chancery Division hears cases concerning trusts, bankruptcy and corporate issures.•Appeals are to the Civil Division of the Court of Appeal and are heard by three judges who will decide the outcome by a majority.• A further appeal to the Supreme Court for the United Kingdom may be permitted if it involves an issue of public interests.3. JURISDICTION OF CRIMINAL COURTS•All criminal cases begin in magistrates’ courts where the case is introduced into the system.•Certain types of offences are known as indictable offences, these are serious offences and can only be heard in Crown Court. Other less serious summary offences are heard summarily in the magistrates’court.•Where an offence falls in between the two, it can be ‘triable either way’, the defendant will have the choice to be tried at the magistrates’ court or at the Crown Court.•Where the decision in a criminal case is appealled against, a court further up the hierarchy will hear it.•Appeals from magistrates’ courts are either to the Crown Court or the Queen’s Bench Division of the High Court.•Case stated appeals from the Crown Court are made to QBD. ‘Case stated’ is a legal function to review a magistrates’ court decision on a point of law , it means the law w as misinterpreted by the magistrate.•Appeals from the Crown Court are made to the Court of Appeal and this may be appealled to the Supreme Court for the United Kingdom if it involves an issue of publicinterests.4. THE MAIN CIVIL COURTS IN THE ENGLISH LEGAL SYSTEMMagistrates’ court•The magistrates’ court is mainly a criminal court, but it also has original jurisdiction in many civil cases, such as liscensing and family issues.•It will also hear claims for recovery of unpaid local authority charges and council tax(英国家庭税).County CourtCounty courts have civil jurisdiction only, it deal with almost every kind of civil case within its serve areas. The main limits to its jurisdiction are financial. It is involved in the following matters: •Contact and tort•Equity matters•Probate matters•Disputes concerning land•Undefended matrimonial cases•Some bankruptcy, company winding-up and admiralty cases（海事裁判）.High CourtThe High Court are divided into three divisions.•The Queen’s Bench Divison hears cases concerning contract and tort issues. It also hasa Commercial Court and an Admiralty Court. A divisionl court of the QBD has anappellate jurisdiction on appeals from magistrates’ court and tribunals.•The Family Division hears cases concerning children and matrimonial issues. The Family Division also has a limited appellate jurisdiction on some appeals from theMagistrates’ Court.•The Chancery Division hears cases concerning trusts, mortgage, bankruptcy, taxation, probate and corporate issures. It also has a Patents Court and a Company Court, which deals with liquidations and other company proceedings.Appeal courtsThe civil court which have an exclusively appellate jurisdiction are the Civil Division of the Court of Appeal and the Supreme Court for the United Kingdom.Court of Appeal•The Court of Appeal hears appeals from the County Court, High Court and several sepcial tribunals.•It reviews the evidence and the legal opinions and makes its decisions based on them.•Cases are heard by three judges ( known as Lord Justices of Appeal) who will decide the outcome by a majority..Supreme Court for the United Kingdom•The Supreme Court for the United Kingdom is the highest appeal court in the English legal system. Cases are heard by Justices of the Supreme Court.•The court hears appeals from the Court of Appeal and also appeals from the High Court, under the ‘leapfrog procedure’ .5. THREE TRACK SYSTEM FOR THE ALLOCATION OF CIVIL CASESThe Civil Procedure Rules (CPR 民事程序规定) introduced a three track system for the allocation of civil cases. Generally speaking, county courts hear small track cases and fast track cases and the High Court hears multi-track cases.•In the small claims track, claims of no more than £5,000 will be heard. These are cases to be dealt with quickly and informallly, often without the need for legal represetation or a full hearing. Parties can consent to use the small claims track if the value of the claimexceeds the limits, but this has to be subject to the court's approval.•In the fast claims track, claims under £25,000 may be heard. There is a strictly limited procedure designed to enable cases to be heard within a short but reasonable timescale.Costs are fixed and hearings are no longer than one day.•The multi-track is intended to provide a new and more flexible regime for the more complex claims, which has a value of more than £15,000. An initial ‘case managementconference’ will be held to encourage the parties to resolve the dispute or to consider the alternative dispute resolution. The trial judge sets a budget and a final timetable for thetrial.•Claimants of cases between £15,000 and £25,000 have the choice of using the fast or multi track, although judges may insist complex cases are heard under the multi track.Chapter 2 Sources of English lawSOURCESCase law Statute CustomCommon Equity Primary SecondarylawSources of English law•There are three main sources of English law, namely case law, legislation (statute) and custom.•Broadly speaking, case law is made and developed in the courts and legislation is made by the legislature（立法机关，立法团体） in Parliament.•Since both of these sources create law today, they can be considered as contemporary.•However, local customs, which developed historically and have existed for a very long time, are not considered as contemporary.1. CASE LAW AS A SOURCE OF LAW•Case law is is made in the courts according to the common law and equity.•Both common law and equity are the product of decisions in the courts made by judges who interpret and apply previous cases based on the doctrine of binding precedent.•This doctrine provides that once a principle of law has been decided, it becomes a precedent which binds the lower courts in cases with materially the same facts.•If the facts of the case are not materially the same as those of the relevant precedent, the precedent may be ‘distinguished’ and not be followed.•Only statements of law made by judges can form precedent.•These statements can be divided into ratio decidendi and obiter dicta.•Only the ratio decidendi forms the basis of precedent as it is this reasoning which is vital to his decision.•Obiter dicta are statements of general law (or hypothetical situations) which are not necessary for the decision and hence are not binding.•Whether the doctrine applies will depend on the status of the court dealing with the case.There is a hierarchy of courts with the lower courts being bound to follow thedecisions of the higher courts.•For example, magistrates’ courts and county courts are bound by the decision of the High Court, the Court of Appeal and the Supreme Court for the United Kingdom.2. DOCTRINE OF PRECEDENTThe doctrine of binding precedent•The doctrine of binding precedent, or stare decisis, is essential to the English legal system.•This doctrine provides that once a principle of law has been decided in court, it becomes a precedent which binds the lower courts in cases with materially the samefacts.•The purpose of the doctrine is to provide consistency, coherency and therefore predictablity and fairness in the development of the case law.Judgements• A judgement in a case will start with a description of the facts and probably a review of earlier precedents.•Then the judge will make statements of law applicable to the legal problems raised by the material facts.•These statements can be divided into ratio decidendi and obiter dicta.Ratio dicidendi•Only a proposition(论点，主张) of law, rather than a statement of fact, will be binding.•Ratio dicidendi can be difined as ‘any rule of law, express or implied, treated by a judge as a necessary step in reaching his conclusion, having regard to the line of reasoning adopted by him, or a necessary part of his direction to the jury. ‘ (Cross)Obiter dicta•Obiter dicta are statements of general law (or hypothetical situations) which are not necessary for the decision in the case.•The obiter dicta are of persusive authority only and do not bind lower court. They may be taken into account but need not be followed.Difference between them•The ratio decidendi forms the basis of precedent as it is this reasoning which is vital to judge’s decision.•It is not always easy to distinguish between the ratio decidendi and the obiter dicta.Judges do not always make clear in their comments whether a particular statement orconclusion is ratio or obiter. Indeed, in a case heard by more than one judge, each judge may provide a different ratio decidendi in support of a common decision.The hierarchy of the courts in relation to the operation of precedent(a) the Supreme Court for the United Kindom – binds all lower courts but itself(exceptional cases)(b) Court of Appeal–binds all lower courts and itself(c) High CourtJudge sitting alone – binds all lower courts not divisional courtsJudges sitting together – binds all lower courts and divisional courts(d) CrownMagistrates–bind no-one at allCountyMagistrates’, County and Crown Courts•Decisions of the Magistrates’ Courts and County Courts do not consititute precedent and thereofore not bind on any court, but each of them is bound by decisions of the High Court, Court of Appeal and the Supreme Court for the United Kingdom.•The Crown Court is also bound by the superior courts and its decisions are of persuasive authority only.High court• A decision of the High Court made by an individual judge binds all lower courts, but not another High Court judge. However, it is of persuasive authority and tends to befollowed in practice.• A decison of Divisional Court usually binds another divisional court.Court of Appeal•Decisions of the Court of Appeal binds all English courts except the Supreme Court for the United Kingdom.•The court is normally bound by its own previous majority and unanimous (意见一致的) decisions, and by those of the Supreme Court for the United Kingdom.The Supreme Court for the United Kingdom•The Supreme Court for the United Kingdom stands at the apex of the English judicial system. Its decisions binds all other English courts.•Itself is bound by its own previous decisions, but it reserves the rights to depart from its own precedents in exceptional cases, although this is rarely exercised.Reversing, overruling and distinguishingPrecedent• A precedent is a previous court decision which another court is bound to follow by deciding a subsequent case in the same way.•In certain circumstances, a judge may not wish to follow an previous decision and it may be open to them to reverse, overrule or distinguish the precedent.Reverse•When the decision of a lower court is appealled to a higher one, the higher court may reverse the decision if they feel the lower court has wrongly interpreted the law. Theoriginal decision cannot form a precedent.•For example, if the Court of Appeal reverse the decision of the High Court, the first decision cannot be a precedent but the reversed decision can.•When a decision is reversed, the higher court is usually also overruling the lower court’s statement of the law.Overrule•Higher courts may overrule the decisions of lower courts, depriving (剥夺) their precedent status, if they di sagree with the lower court’s statement of law.•Overruling involves an earlier case, rather than a case which is the subject of an appeal.•When a decision is overruled, the law is changed with retrospective effect. Judges are usually cautious before overruling a long-standing precedent, but this is sometimesnecessary, for example where what is acceptable within a particular society changes. Distinguishing•For a precedent to be followed, the facts of the previous case and the case under consideration must be materially the same.•If not, the precedent may be ‘distinguished’ and not followed.3. THE ADVANTAGES AND DISADVANTAGES OF THE DOCTRINEAdvantagesCertainty•Law is decided fairly and predictably.•The need for costly and time-consuming litigation can be avoided.•The doctrine also gives guidance to the judges and leads to consistency in decisions from different judges in different courts and in different parts of the country.Clarity•The doctrine gives rise to a healthy source of statements of legal principle that can helpfully and clearly be applied to new cases generally.•This leads to a saving of time for all concerned, it don’t need to be put before the courts and argued again.Flexibility•The doctrine allows the law to grow and be developed in accordance with changing needs and circumstances of society.•It also allows a much more flexible judge-made law than Parliament-enacted legislation. PracticalityFaineasDisvantages•Bulk.•Restricts judicial discretion.•reactive system.•Lack of democratic accountability.4. LEGISLATION AS A SOURCE OF LAW AND ITS ADVANTAGES•Statute law is made by Parliament.•Parliament may make law as it sees fit – it may repeal(撤销) earlier statutes, overrule case law or make law in new areas previously unregulated.•The validity of an Act of Parliament cannot be questioned. ( Cheney v Conn 1968).•However, this principle of Parliamentary sovereignty[ˈsɔvərɪnti:](最高统治权、君权) has been reduced somewhat by the UK’s membership of the European Union which requires its law to be brought into line with the EU’s treaties and directives.•Additionally, the Human Rights Act 1998 requires new laws to be compatible with the European Convention on Human Right.•Statute law may be fresh legislation or may be a consolidation of existing statutes and their amendment, for example the Company Act 2006.•It may also be a codification (法律汇编) of existing statute and case law, for example the Sale of Goods Act 1979.•The courts are bound to apply relevant statute law and cannot disregard or rewrite it.•Whatever the nature of the legislation, the role of judges to interpret and apply it is the same.•Judicial interpretation (司法解释) might be needed because of ambiguity in drafting or uncertainty as to whether a particular set of facts are within the scope of a statute, orwhere unforeseeable developments have occurred since the statute was passed.•The complexity of modern legislation makes a great deal of details which cannot be easily included in an Act.•Therefore, powers may be given to a minister or a public body to make laws for specified purpose in the form of statutory instruments, bye-law and Rules of Court.•Such delegated legislation has the same effect as the empowering act itself. Advantages•They can in theory deal with any problem•They are carefully constructed codes of law•New problems in society or unwelcome development can be dealt with quickly•Reponsive to public opinion as parliament is elected at least every five years5. DELEGATED LEGISLATION•The complexity of modern legislation makes a great deal of details which cannot be easily included in an Act.•Therefore, powers may be given to a minister or public body to make laws for specified purpose in the form of statutory instruments, bye-law and Rules of Court.•The legislation sets out the broad objective and purpose of the Act, leaving the detail to be delegated to individuals or bodies outside Parliament.•Such delegated legislation has the same effect as the empowering act itself.There are various forms of delegated legislation•Statutory instruments: these are made by government minister who has delegated the relevant powers.•Bye-laws: these are made by local authorities and apply within a specific locality•Rules of court: these may be made by the judiciary (法官) to control court procedure.•Orders in council: these are often made by the Privy Council (枢密院).•Professional rules: Parliament also gives powers to various professional bodies to regulate the conduct of its members.The control over the delegated legislationAs delegated legislation is often created by unelected individuals and bodies, there are controls over it.•It may have to be approved by an affirmative resolution of Parliament and/or be laid before Parliament for 40 days before it takes effect.•It may be challeged in the courts. Firstly, on the ground that Parliament exceeded its authority to delegate and has acted ultra vires, or secondly, the lagislation has beenmade without the correct procedure.•There are standing (永久的，常设的) Scrutiny Committees (检查委员会) of both Houses whose duty is to examine delegated legislation from a technical point of view and theymay raise objections if necessary. However, they have no authority to its nature orcontent.•The Human Rights Act 1998 gives courts power to strike out any delegated lagislation that runs contrary to the HRA.Advantages•Volume of work. Delegated lagislation enables Parliament to concentrate on the broader principles of the legislative framework, rather than getting bogged down indetails.•Speed. Delegated legislation enables new laws to be passed much more quickly, especially advantageous in times of emergency.•Flexibility. Delegated legislation enables great flexibility, because regulations can be altered later without the need to revert to (回到) Parliament.•Expertise. The subject of new legislation is often highly detailed, technical and complex. It therefore makes sense for the exact content, and the wording（措辞） isarrived at by consultation with professional, commercial or industrial groups outsideParliament who have the relevant expertise.•Tider primary legislation. The primary legislation is more concise (精炼) because the details are left to other delegated legislation documentation(程序说明书). Disadvantages:•Volume. The volume of delegated legislation means that it can become difficult for Parliment ( and others) to keep track of the effect of the legislation.•Unconstitutional.（违反宪法的) Although Parliament is ultimately responsible for the legislation, it is likely that much of the detail has actually been drafted and finalised by individual ministers or by civil servants. Since civil servants are unelected, the degree to which law-making powers should be delegated to them is a matter for some debate. 6. STATUTORY INTERPRETATIONLegislation must be interpreted correctly before judges can apply it fairly. In order to determine the meaning of such legislation, the court will apply a number of well-established rules and principles to interpret the statute.•Literal rule: The literal rule requires the words to be given their literal and grammatical meaning rather than what the judges think they mean.•Golden rule: The golden rule expands the literal rule. It requires the words to be given their plain, ordinary and literal meaning unless this would give rise to manifest (明显的) absurdity(谬论) or inconsistency with the rest of the statute.•Mischief rule: Under the mischief rule, a judges considers what mischief (损害) the Act .Where a statute is designed to remedy a weakness in the law, the correct interpretation is the one that achieves it.•Purposive approach : It requires the words to be given not only their ordinary, literal and grammatical meaning, but also with reference to the context and purpose of thelegislation.•Ejusdem generis (同类) : Where general words follow specific words, the general words must be interpreted by reference to(参考) the specific words used.7. HUMAN RIGHTS ACT 1998The Articles of the European Convention on Human Rights have now been enshrined(铭记) into English law as the Human Right Act 1998, enacted in 2000. The main provisions are: •The right to life•The right to property•The right to education•The right to marry•The right to a fair trial•The right to liberty and security•The right to free elections.•The right to respect for privacy, family life•Freedom of thought, conscience and religion•Freedom of expression, assembly and association•No punishment without law•No discrimination in rightsThe Act binds the pubilc authorities•The Act binds the pubilc authorities, which can be defined as bodies undertaking functions of a public nature, including government departments, local authorities, courts and schools.Non-government individuals or bodies can rely on the actImpact on UK law•The main impact of the HRA1998 on UK law is that UK courts are now required to interpret UK law in a way that is compatible with the Convention. It means that a courtmust take into account the previous decisions of the European Court of Human Rights.•If a court feels that a provision of primary legislation ( ie an Act of Parliament) is incompatible with the Convention, it can make a declaration of incompatibility. It is thenup to the Government to take action to remedy the incompatibility.Chapter 3 Offer and AcceptanceNature of a contractFORMATION & NATURE OF A CONTRACTAgreement Intention ConsiderationThe first essential element in the formation of a binding contract is agreement. This is ususlly evidenced by offer and acceptance.1. OFFER•In the law of contract , an offer is a definite promise to another to be bound on specific terms. It is capable of (能够) acceptance so as to form a binding contract.•An offer cannot be in vague terms, for example a promise to buy a horse if it is ‘lucky’ (Gunthing v Lynn 1831).•An offer can be made to an induvidual, a class of persons or to the world at large and it can be accepted by the conduct of the offeree ( Carlill v Carbolic Smoke Ball Co 1893).•Once an offer has been accepted, a binding contract is created. Either party may legally enforce the promise of the other.•Ture offers must be distinguished from a mere supply of information and statement of intention.Supply of information• A mere supply of information is not an offer, because there is no intention to be bound.•For example, stating the minimum price that one would consider if a sale were to be agreed does not make an offer ( Harvey v Facey 1893).Statement of intention•Similarly, a mere statement of intention is not an offer neither.•For example, advertising that an event such as an auction will take place does not make an offer. (Harris v Nickerson 1873).•Only the offer made with the intention that it shall become binding when accepted may form a binding contract.2. INVITATION TO TREAT•An invitation to treat is an indication that someone is prepared to receive offers with the intention to form a binding contract.•There is no binding contract until this offer is made and, in turn , accepted.Case law has established a number of accepted principles to determine whether a statement is an offer or merely an invitation to treat.Advertisements•An advertisement of goods for sale is usually an attempt to induce offers (Partridge v Crittenden 1968)•However, in limited circumstances, words of an advertisement can be an offer made to the whole world (Carlill v Carbolic Smoke Ball Co. 1893)Display of goods in a shop window•In Fisher v Bell 1961, a shopkeeper was prosecuted for offering for sale an offensive weapon by exhibiting a flick knife in the shop window.•It was held that this was not an offer for sale, but an invitation to treatExhibitions of goods in a self –service shop•In Pharmaceutical Society of G.B. v Boots Cash Chemists 1952, the chemists exhibited various goods on self-service shelves.•It was held that this was not an offer for sale, but an invitation to treat. Customers took up the invitation by taking the goods to the cash point, thereby making an offer to buy which was accepted by the shopkeeper.Auction sales（拍卖）•An auctioneer’s request for bid is not an offer to sell to the highest bidder, but an invitation to treat.•The bid itself is an offer, which the auctioneer is then free to accept or reject ( Payne v Cave 1789).Invitations for tenders (竞标)•An invitation to tender is not an offer to contract with the party offering the lowest price, but an invitation to treat.•The tender itself is an offer, which the person who issued the invitation is then free to accept or reject.3. ACCEPTANCE OF AN OFFERACCEPTANCE•Valid acceptance of a valid offer is one of the essencials of a contract•An acceptance must be an unqualified (无条件的) agreement to the terms of the offer.•Acceptance is generally not effective until communicated to the offeror, except where the ‘postal rule’ applies.• A purported acceptance which introduces any new terms is a counter-offer, which has the effect of terminating the original offer ( Hyde v Wrench 1840).Request for information• A response to an offer which is actually a request for further information will not form an acceptance.Acceptance ‘ subject to contract’•Acceptance ‘ subject to contract’ means tha t the offeree is agreeable to the terms of the offer but proposes that the parties should negotiate a formal contract.•Neither party is bound until the formal contract is signed.Letters of intent (LOI 合作意向书)• A letter of intent is a strong indication given by one party to another to say that he is likely to place a contract with him.Method of acceptance•The acceptance of an offer is made by a person authorised to do so, usually the offeree or his authorised agent.•The acceptance may be by express words or be inferred from conduct (Brogden v Metropolitan Rly Co 1877).•In some circumstance (Carlill v Carbolic Smoke Ball Co 1893), performance of the act required by the offer or advertisement consititutes an acceptacne.•There must be some act on the part of the offeree since passive inaction or silence is not capable of acceptance ( Felthose v Bindley 1862).The communication of acceptance•Acceptance is generally not effective until communicated to the offeror, except where the ‘postal rule’ applies, or t he offeror waives the need for communication.•The offeror may specify the sole means of communication, in which case only compliance with their terms will suffice （满足……的需要）.•If the offeror specifies a means of communication but does not make it absolutely compulsory, then acceptance by another means which is equally expeditious and does。

专八英语阅读

英语专业八级考试TEM-8阅读理解练习册（1）(英语专业2012级)UNIT 1Text AEvery minute of every day, what ecologist生态学家James Carlton calls a global ―conveyor belt‖, redistributes ocean organisms生物.It’s planetwide biological disruption生物的破坏that scientists have barely begun to understand.Dr. Carlton —an oceanographer at Williams College in Williamstown,Mass.—explains that, at any given moment, ―There are several thousand marine species traveling… in the ballast water of ships.‖ These creatures move from coastal waters where they fit into the local web of life to places where some of them could tear that web apart. This is the larger dimension of the infamous无耻的，邪恶的invasion of fish-destroying, pipe-clogging zebra mussels有斑马纹的贻贝.Such voracious贪婪的invaders at least make their presence known. What concerns Carlton and his fellow marine ecologists is the lack of knowledge about the hundreds of alien invaders that quietly enter coastal waters around the world every day. Many of them probably just die out. Some benignly亲切地，仁慈地—or even beneficially — join the local scene. But some will make trouble.In one sense, this is an old story. Organisms have ridden ships for centuries. They have clung to hulls and come along with cargo. What’s new is the scale and speed of the migrations made possible by the massive volume of ship-ballast water压载水— taken in to provide ship stability—continuously moving around the world…Ships load up with ballast water and its inhabitants in coastal waters of one port and dump the ballast in another port that may be thousands of kilometers away. A single load can run to hundreds of gallons. Some larger ships take on as much as 40 million gallons. The creatures that come along tend to be in their larva free-floating stage. When discharged排出in alien waters they can mature into crabs, jellyfish水母, slugs鼻涕虫，蛞蝓, and many other forms.Since the problem involves coastal species, simply banning ballast dumps in coastal waters would, in theory, solve it. Coastal organisms in ballast water that is flushed into midocean would not survive. Such a ban has worked for North American Inland Waterway. But it would be hard to enforce it worldwide. Heating ballast water or straining it should also halt the species spread. But before any such worldwide regulations were imposed, scientists would need a clearer view of what is going on.The continuous shuffling洗牌of marine organisms has changed the biology of the sea on a global scale. It can have devastating effects as in the case of the American comb jellyfish that recently invaded the Black Sea. It has destroyed that sea’s anchovy鳀鱼fishery by eating anchovy eggs. It may soon spread to western and northern European waters.The maritime nations that created the biological ―conveyor belt‖ should support a coordinated international effort to find out what is going on and what should be done about it. (456 words)1.According to Dr. Carlton, ocean organism‟s are_______.A.being moved to new environmentsB.destroying the planetC.succumbing to the zebra musselD.developing alien characteristics2.Oceanographers海洋学家are concerned because_________.A.their knowledge of this phenomenon is limitedB.they believe the oceans are dyingC.they fear an invasion from outer-spaceD.they have identified thousands of alien webs3.According to marine ecologists, transplanted marinespecies____________.A.may upset the ecosystems of coastal watersB.are all compatible with one anotherC.can only survive in their home watersD.sometimes disrupt shipping lanes4.The identified cause of the problem is_______.A.the rapidity with which larvae matureB. a common practice of the shipping industryC. a centuries old speciesD.the world wide movement of ocean currents5.The article suggests that a solution to the problem__________.A.is unlikely to be identifiedB.must precede further researchC.is hypothetically假设地，假想地easyD.will limit global shippingText BNew …Endangered‟ List Targets Many US RiversIt is hard to think of a major natural resource or pollution issue in North America today that does not affect rivers.Farm chemical runoff残渣, industrial waste, urban storm sewers, sewage treatment, mining, logging, grazing放牧,military bases, residential and business development, hydropower水力发电,loss of wetlands. The list goes on.Legislation like the Clean Water Act and Wild and Scenic Rivers Act have provided some protection, but threats continue.The Environmental Protection Agency (EPA) reported yesterday that an assessment of 642,000 miles of rivers and streams showed 34 percent in less than good condition. In a major study of the Clean Water Act, the Natural Resources Defense Council last fall reported that poison runoff impairs损害more than 125,000 miles of rivers.More recently, the NRDC and Izaak Walton League warned that pollution and loss of wetlands—made worse by last year’s flooding—is degrading恶化the Mississippi River ecosystem.On Tuesday, the conservation group保护组织American Rivers issued its annual list of 10 ―endangered‖ and 20 ―threatened‖ rivers in 32 states, the District of Colombia, and Canada.At the top of the list is the Clarks Fork of the Yellowstone River, whereCanadian mining firms plan to build a 74-acre英亩reservoir水库，蓄水池as part of a gold mine less than three miles from Yellowstone National Park. The reservoir would hold the runoff from the sulfuric acid 硫酸used to extract gold from crushed rock.―In the event this tailings pond failed, the impact to th e greater Yellowstone ecosystem would be cataclysmic大变动的，灾难性的and the damage irreversible不可逆转的.‖ Sen. Max Baucus of Montana, chairman of the Environment and Public Works Committee, wrote to Noranda Minerals Inc., an owner of the ― New World Mine‖.Last fall, an EPA official expressed concern about the mine and its potential impact, especially the plastic-lined storage reservoir. ― I am unaware of any studies evaluating how a tailings pond尾矿池，残渣池could be maintained to ensure its structural integrity forev er,‖ said Stephen Hoffman, chief of the EPA’s Mining Waste Section. ―It is my opinion that underwater disposal of tailings at New World may present a potentially significant threat to human health and the environment.‖The results of an environmental-impact statement, now being drafted by the Forest Service and Montana Department of State Lands, could determine the mine’s future…In its recent proposal to reauthorize the Clean Water Act, the Clinton administration noted ―dramatically improved water quality since 1972,‖ when the act was passed. But it also reported that 30 percent of riverscontinue to be degraded, mainly by silt泥沙and nutrients from farm and urban runoff, combined sewer overflows, and municipal sewage城市污水. Bottom sediments沉积物are contaminated污染in more than 1,000 waterways, the administration reported in releasing its proposal in January. Between 60 and 80 percent of riparian corridors (riverbank lands) have been degraded.As with endangered species and their habitats in forests and deserts, the complexity of ecosystems is seen in rivers and the effects of development----beyond the obvious threats of industrial pollution, municipal waste, and in-stream diversions改道to slake消除the thirst of new communities in dry regions like the Southwes t…While there are many political hurdles障碍ahead, reauthorization of the Clean Water Act this year holds promise for US rivers. Rep. Norm Mineta of California, who chairs the House Committee overseeing the bill, calls it ―probably the most important env ironmental legislation this Congress will enact.‖ (553 words)6.According to the passage, the Clean Water Act______.A.has been ineffectiveB.will definitely be renewedC.has never been evaluatedD.was enacted some 30 years ago7.“Endangered” rivers are _________.A.catalogued annuallyB.less polluted than ―threatened rivers‖C.caused by floodingD.adjacent to large cities8.The “cataclysmic” event referred to in paragraph eight would be__________.A. fortuitous偶然的，意外的B. adventitious外加的，偶然的C. catastrophicD. precarious不稳定的，危险的9. The owners of the New World Mine appear to be______.A. ecologically aware of the impact of miningB. determined to construct a safe tailings pondC. indifferent to the concerns voiced by the EPAD. willing to relocate operations10. The passage conveys the impression that_______.A. Canadians are disinterested in natural resourcesB. private and public environmental groups aboundC. river banks are erodingD. the majority of US rivers are in poor conditionText CA classic series of experiments to determine the effects ofoverpopulation on communities of rats was reported in February of 1962 in an article in Scientific American. The experiments were conducted by a psychologist, John B. Calhoun and his associates. In each of these experiments, an equal number of male and female adult rats were placed in an enclosure and given an adequate supply of food, water, and other necessities. The rat populations were allowed to increase. Calhoun knew from experience approximately how many rats could live in the enclosures without experiencing stress due to overcrowding. He allowed the population to increase to approximately twice this number. Then he stabilized the population by removing offspring that were not dependent on their mothers. He and his associates then carefully observed and recorded behavior in these overpopulated communities. At the end of their experiments, Calhoun and his associates were able to conclude that overcrowding causes a breakdown in the normal social relationships among rats, a kind of social disease. The rats in the experiments did not follow the same patterns of behavior as rats would in a community without overcrowding.The females in the rat population were the most seriously affected by the high population density: They showed deviant异常的maternal behavior; they did not behave as mother rats normally do. In fact, many of the pups幼兽，幼崽, as rat babies are called, died as a result of poor maternal care. For example, mothers sometimes abandoned their pups,and, without their mothers' care, the pups died. Under normal conditions, a mother rat would not leave her pups alone to die. However, the experiments verified that in overpopulated communities, mother rats do not behave normally. Their behavior may be considered pathologically 病理上，病理学地diseased.The dominant males in the rat population were the least affected by overpopulation. Each of these strong males claimed an area of the enclosure as his own. Therefore, these individuals did not experience the overcrowding in the same way as the other rats did. The fact that the dominant males had adequate space in which to live may explain why they were not as seriously affected by overpopulation as the other rats. However, dominant males did behave pathologically at times. Their antisocial behavior consisted of attacks on weaker male,female, and immature rats. This deviant behavior showed that even though the dominant males had enough living space, they too were affected by the general overcrowding in the enclosure.Non-dominant males in the experimental rat communities also exhibited deviant social behavior. Some withdrew completely; they moved very little and ate and drank at times when the other rats were sleeping in order to avoid contact with them. Other non-dominant males were hyperactive; they were much more active than is normal, chasing other rats and fighting each other. This segment of the rat population, likeall the other parts, was affected by the overpopulation.The behavior of the non-dominant males and of the other components of the rat population has parallels in human behavior. People in densely populated areas exhibit deviant behavior similar to that of the rats in Calhoun's experiments. In large urban areas such as New York City, London, Mexican City, and Cairo, there are abandoned children. There are cruel, powerful individuals, both men and women. There are also people who withdraw and people who become hyperactive. The quantity of other forms of social pathology such as murder, rape, and robbery also frequently occur in densely populated human communities. Is the principal cause of these disorders overpopulation? Calhoun’s experiments suggest that it might be. In any case, social scientists and city planners have been influenced by the results of this series of experiments.11. Paragraph l is organized according to__________.A. reasonsB. descriptionC. examplesD. definition12．Calhoun stabilized the rat population_________.A. when it was double the number that could live in the enclosure without stressB. by removing young ratsC. at a constant number of adult rats in the enclosureD. all of the above are correct13.W hich of the following inferences CANNOT be made from theinformation inPara. 1?A. Calhoun's experiment is still considered important today.B. Overpopulation causes pathological behavior in rat populations.C. Stress does not occur in rat communities unless there is overcrowding.D. Calhoun had experimented with rats before.14. Which of the following behavior didn‟t happen in this experiment?A. All the male rats exhibited pathological behavior.B. Mother rats abandoned their pups.C. Female rats showed deviant maternal behavior.D. Mother rats left their rat babies alone.15. The main idea of the paragraph three is that __________.A. dominant males had adequate living spaceB. dominant males were not as seriously affected by overcrowding as the otherratsC. dominant males attacked weaker ratsD. the strongest males are always able to adapt to bad conditionsText DThe first mention of slavery in the statutes法令，法规of the English colonies of North America does not occur until after 1660—some forty years after the importation of the first Black people. Lest we think that existed in fact before it did in law, Oscar and Mary Handlin assure us, that the status of B lack people down to the 1660’s was that of servants. A critique批判of the Handlins’ interpretation of why legal slavery did not appear until the 1660’s suggests that assumptions about the relation between slavery and racial prejudice should be reexamined, and that explanation for the different treatment of Black slaves in North and South America should be expanded.The Handlins explain the appearance of legal slavery by arguing that, during the 1660’s, the position of white servants was improving relative to that of black servants. Thus, the Handlins contend, Black and White servants, heretofore treated alike, each attained a different status. There are, however, important objections to this argument. First, the Handlins cannot adequately demonstrate that t he White servant’s position was improving, during and after the 1660’s; several acts of the Maryland and Virginia legislatures indicate otherwise. Another flaw in the Handlins’ interpretation is their assumption that prior to the establishment of legal slavery there was no discrimination against Black people. It is true that before the 1660’s Black people were rarely called slaves. But this shouldnot overshadow evidence from the 1630’s on that points to racial discrimination without using the term slavery. Such discrimination sometimes stopped short of lifetime servitude or inherited status—the two attributes of true slavery—yet in other cases it included both. The Handlins’ argument excludes the real possibility that Black people in the English colonies were never treated as the equals of White people.The possibility has important ramifications后果，影响.If from the outset Black people were discriminated against, then legal slavery should be viewed as a reflection and an extension of racial prejudice rather than, as many historians including the Handlins have argued, the cause of prejudice. In addition, the existence of discrimination before the advent of legal slavery offers a further explanation for the harsher treatment of Black slaves in North than in South America. Freyre and Tannenbaum have rightly argued that the lack of certain traditions in North America—such as a Roman conception of slavery and a Roman Catholic emphasis on equality— explains why the treatment of Black slaves was more severe there than in the Spanish and Portuguese colonies of South America. But this cannot be the whole explanation since it is merely negative, based only on a lack of something. A more compelling令人信服的explanation is that the early and sometimes extreme racial discrimination in the English colonies helped determine the particular nature of the slavery that followed. (462 words)16. Which of the following is the most logical inference to be drawn from the passage about the effects of “several acts of the Maryland and Virginia legislatures” (Para.2) passed during and after the 1660‟s?A. The acts negatively affected the pre-1660’s position of Black as wellas of White servants.B. The acts had the effect of impairing rather than improving theposition of White servants relative to what it had been before the 1660’s.C. The acts had a different effect on the position of white servants thandid many of the acts passed during this time by the legislatures of other colonies.D. The acts, at the very least, caused the position of White servants toremain no better than it had been before the 1660’s.17. With which of the following statements regarding the status ofBlack people in the English colonies of North America before the 1660‟s would the author be LEAST likely to agree?A. Although black people were not legally considered to be slaves,they were often called slaves.B. Although subject to some discrimination, black people had a higherlegal status than they did after the 1660’s.C. Although sometimes subject to lifetime servitude, black peoplewere not legally considered to be slaves.D. Although often not treated the same as White people, black people,like many white people, possessed the legal status of servants.18. According to the passage, the Handlins have argued which of thefollowing about the relationship between racial prejudice and the institution of legal slavery in the English colonies of North America?A. Racial prejudice and the institution of slavery arose simultaneously.B. Racial prejudice most often the form of the imposition of inheritedstatus, one of the attributes of slavery.C. The source of racial prejudice was the institution of slavery.D. Because of the influence of the Roman Catholic Church, racialprejudice sometimes did not result in slavery.19. The passage suggests that the existence of a Roman conception ofslavery in Spanish and Portuguese colonies had the effect of _________.A. extending rather than causing racial prejudice in these coloniesB. hastening the legalization of slavery in these colonies.C. mitigating some of the conditions of slavery for black people in these coloniesD. delaying the introduction of slavery into the English colonies20. The author considers the explanation put forward by Freyre andTannenbaum for the treatment accorded B lack slaves in the English colonies of North America to be _____________.A. ambitious but misguidedB. valid有根据的but limitedC. popular but suspectD. anachronistic过时的，时代错误的and controversialUNIT 2Text AThe sea lay like an unbroken mirror all around the pine-girt, lonely shores of Orr’s Island. Tall, kingly spruce s wore their regal王室的crowns of cones high in air, sparkling with diamonds of clear exuded gum流出的树胶; vast old hemlocks铁杉of primeval原始的growth stood darkling in their forest shadows, their branches hung with long hoary moss久远的青苔;while feathery larches羽毛般的落叶松,turned to brilliant gold by autumn frosts, lighted up the darker shadows of the evergreens. It was one of those hazy朦胧的, calm, dissolving days of Indian summer, when everything is so quiet that the fainest kiss of the wave on the beach can be heard, and white clouds seem to faint into the blue of the sky, and soft swathing一长条bands of violet vapor make all earth look dreamy, and give to the sharp, clear-cut outlines of the northern landscape all those mysteries of light and shade which impart such tenderness to Italian scenery.The funeral was over,--- the tread鞋底的花纹/ 踏of many feet, bearing the heavy burden of two broken lives, had been to the lonely graveyard, and had come back again,--- each footstep lighter and more unconstrained不受拘束的as each one went his way from the great old tragedy of Death to the common cheerful of Life.The solemn black clock stood swaying with its eternal ―tick-tock, tick-tock,‖ in the kitchen of the brown house on Orr’s Island. There was there that sense of a stillness that can be felt,---such as settles down on a dwelling住处when any of its inmates have passed through its doors for the last time, to go whence they shall not return. The best room was shut up and darkened, with only so much light as could fall through a little heart-shaped hole in the window-shutter,---for except on solemn visits, or prayer-meetings or weddings, or funerals, that room formed no part of the daily family scenery.The kitchen was clean and ample, hearth灶台, and oven on one side, and rows of old-fashioned splint-bottomed chairs against the wall. A table scoured to snowy whiteness, and a little work-stand whereon lay the Bible, the Missionary Herald, and the Weekly Christian Mirror, before named, formed the principal furniture. One feature, however, must not be forgotten, ---a great sea-chest水手用的储物箱,which had been the companion of Zephaniah through all the countries of the earth. Old, and battered破旧的，磨损的, and unsightly难看的it looked, yet report said that there was good store within which men for the most part respect more than anything else; and, indeed it proved often when a deed of grace was to be done--- when a woman was suddenly made a widow in a coast gale大风，狂风, or a fishing-smack小渔船was run down in the fogs off the banks, leaving in some neighboring cottage a family of orphans,---in all such cases, the opening of this sea-chest was an event of good omen 预兆to the bereaved丧亲者;for Zephaniah had a large heart and a large hand, and was apt有…的倾向to take it out full of silver dollars when once it went in. So the ark of the covenant约柜could not have been looked on with more reverence崇敬than the neighbours usually showed to Captain Pennel’s sea-chest.1. The author describes Orr‟s Island in a(n)______way.A.emotionally appealing, imaginativeB.rational, logically preciseC.factually detailed, objectiveD.vague, uncertain2.According to the passage, the “best room”_____.A.has its many windows boarded upB.has had the furniture removedC.is used only on formal and ceremonious occasionsD.is the busiest room in the house3.From the description of the kitchen we can infer that thehouse belongs to people who_____.A.never have guestsB.like modern appliancesC.are probably religiousD.dislike housework4.The passage implies that_______.A.few people attended the funeralB.fishing is a secure vocationC.the island is densely populatedD.the house belonged to the deceased5.From the description of Zephaniah we can see thathe_________.A.was physically a very big manB.preferred the lonely life of a sailorC.always stayed at homeD.was frugal and saved a lotText BBasic to any understanding of Canada in the 20 years after the Second World War is the country' s impressive population growth. For every three Canadians in 1945, there were over five in 1966. In September 1966 Canada's population passed the 20 million mark. Most of this surging growth came from natural increase. The depression of the 1930s and the war had held back marriages, and the catching-up process began after 1945. The baby boom continued through the decade of the 1950s, producing a population increase of nearly fifteen percent in the five years from 1951 to 1956. This rate of increase had been exceeded only once before in Canada's history, in the decade before 1911 when the prairies were being settled. Undoubtedly, the good economic conditions of the 1950s supported a growth in the population, but the expansion also derived from a trend toward earlier marriages and an increase in the average size of families; In 1957 the Canadian birth rate stood at 28 per thousand, one of the highest in the world. After the peak year of 1957, thebirth rate in Canada began to decline. It continued falling until in 1966 it stood at the lowest level in 25 years. Partly this decline reflected the low level of births during the depression and the war, but it was also caused by changes in Canadian society. Young people were staying at school longer, more women were working; young married couples were buying automobiles or houses before starting families; rising living standards were cutting down the size of families. It appeared that Canada was once more falling in step with the trend toward smaller families that had occurred all through theWestern world since the time of the Industrial Revolution. Although the growth in Canada’s population had slowed down by 1966 (the cent), another increase in the first half of the 1960s was only nine percent), another large population wave was coming over the horizon. It would be composed of the children of the children who were born during the period of the high birth rate prior to 1957.6. What does the passage mainly discuss?A. Educational changes in Canadian society.B. Canada during the Second World War.C. Population trends in postwar Canada.D. Standards of living in Canada.7. According to the passage, when did Canada's baby boom begin?A. In the decade after 1911.B. After 1945.C. During the depression of the 1930s.D. In 1966.8. The author suggests that in Canada during the 1950s____________.A. the urban population decreased rapidlyB. fewer people marriedC. economic conditions were poorD. the birth rate was very high9. When was the birth rate in Canada at its lowest postwar level?A. 1966.B. 1957.C. 1956.D. 1951.10. The author mentions all of the following as causes of declines inpopulation growth after 1957 EXCEPT_________________.A. people being better educatedB. people getting married earlierC. better standards of livingD. couples buying houses11.I t can be inferred from the passage that before the IndustrialRevolution_______________.A. families were largerB. population statistics were unreliableC. the population grew steadilyD. economic conditions were badText CI was just a boy when my father brought me to Harlem for the first time, almost 50 years ago. We stayed at the hotel Theresa, a grand brick structure at 125th Street and Seventh avenue. Once, in the hotel restaurant, my father pointed out Joe Louis. He even got Mr. Brown, the hotel manager, to introduce me to him, a bit punchy强力的but still champ焦急as fast as I was concerned.Much has changed since then. Business and real estate are booming. Some say a new renaissance is under way. Others decry责难what they see as outside forces running roughshod肆意践踏over the old Harlem. New York meant Harlem to me, and as a young man I visited it whenever I could. But many of my old haunts are gone. The Theresa shut down in 1966. National chains that once ignored Harlem now anticipate yuppie money and want pieces of this prime Manhattan real estate. So here I am on a hot August afternoon, sitting in a Starbucks that two years ago opened a block away from the Theresa, snatching抓取，攫取at memories between sips of high-priced coffee. I am about to open up a piece of the old Harlem---the New York Amsterdam News---when a tourist。

黎巴嫩公司建设遇袭VOA原文

黎巴嫩公司建设遇袭VOA原文CAIRO—The resignation last week of Lebanon's pri me minister highlights the long-standing political te nsions in the multi-faith government.The perils of s ectarian politics is being played out with increasin g intensity across the region.In the two years since the conflict in Syria b egan,the fragile sectarian mix in neighboring Lebanon has become only more tense.In the northern city T ripoli,supporters of Syria's Alawite President Basharal-Assad have yet again fought deadly street battl es with Sunni supporters of Syria's rebels.The latest fighting follows the resignation of L ebanon's consensus prime minister,who had tried to h old together a government of Assad-backing Hezbollah with Sunni politicians.Najib Mikati stepped down nominally over domestic issues,but he warned of the “regional fires”touching Lebanon“with their flames.”The sectarian nature of the war next door has prom pted worries Syria could fragment completely along s ectarian lines.Regional security expert Sameh Saif al Yazal,“I c an see in front of me some possibility of Syria s plitting into Alawi country,[with the]capital Latakiya in the western part of Syria;the northern part theK urds;and then the rest of Syria for the rest of S unnis,Druze and everybody else.”While some dismiss the idea as a worst-case sce nario,forces tearing apart Syria reflect the sectaria n actors with influence in Lebanon as well--in part icular Iran with its backing of both the Assad gov ernment and Hezbollah.Christian Donath,a professor at the American Univ ersity in Cairo,says Iran's regional reach has promp ted other nations of the Persian Gulf to get invol ved.“The Qataris and the Saudis both share concerns over Iranian power and I think they are doing wh at they can to stem what they see as a spreading tide of Iranian and Shia influence,"he said.But some argue the rise of Sunni Islamists in the past two years may have prompted Iran's leaders t o see a different kind of foreign influence at play.“I think one of the things they understand is the West wants--that the Arab Spring turns into a sea of Sunni regimes against Iran,”said political soci ologist Said Sadek.While suspicions abound,and while Syria sinks int o what analysts call a proxy war for foreign power s with sectarian agendas,multi-faith Lebanon is tryin g to step back from the brink.。

图形硬件加速的织物自碰撞检测算法

ＪＣｕｎｈｎＬｕＨｕｉｈａｓｕｉｉ
（ｃｏｌｆＣｍｕｅＳｉｃ，如ｎＵｉｒｔ，增０３，ｈｎ）Ｓｈｏｏｏｐｔｒｃｎｅ几ｅｎｖｓｙ鼽ｎ０２￣３Ｃｉａｅｉ
ＡｂｔａｔｓｒｃＳＩｃｌｓｏｅｅｔｎｉｔｅｂｔｅｅｋｏｅｌｔｉｌｔｎｏａｒｓＢｓｎｅａｕｅｆｇａｈｃａｄｒ．｝ｕｅｆｏｌｉｎｄｔｃｉｓｈｏｔｎｃｆｒａ — ｍｅｓｍｕａｉｆｆｂｃ．ｙｕｉｇｎｗｆｔｒｓｏｒｐｉｓｈｒｗａｅｔｅａ — －ｉｏｌｉｏｉｏｌ
纪传舜刘卉
（复旦大学计算机科学与技术学院上海２０３）０４３
摘
要
自碰撞检测是织物实时模拟的瓶颈。利用最新的图形硬件特性，设计了织物模拟的自碰撞检测算法。该算法以质点包
围球为基本计算单元，仅保存计算得到的第一次发生碰撞的信息，而不需要计算出所有的碰撞对。算法在ＣＤＵＡ平台上实现，通过对核函数的一次调用即可完成自碰撞检测，法复杂度为０（）算ｎ。将算法用于由大规模质点构成的织物模拟过程中，试验表明，算
法的ＧＵ实现比相应的ＣＵ实现性能提高１以上，ＰＰ８倍与两遍渲染算法相比，均性能也提高了２％左右。平０
关键词自碰撞检测ＧＵＣＤＰＵＡ织物模拟
ＦＡＢＲＩＥＬＦ．ＣＳＳＣＯＬＬＩＯＮＳＩＤＥＴＥＣＴＩＯＮＡＬＧＯＲＩＴＨＭＡＣＣＥＬＥＲＡＴＥＤＢＹＧＲＡＰＨＩＣＳＨＡＲＤＷＡＲＥ

SD-Branch解决方案高级概述说明书

Security Is the Key to a Dependable SD-Branch SolutionExecutive OverviewThere has been a long history of building networks and then adding on security at the end, as an afterthought. This was no different for branch offices, especially since traditionally, all traffic came back to a central location for security inspection. Dedicated network lines (typically multiprotocol label switching [MPLS]) connected branches back to corporate, and there was little perceived need to worry about security within the branch.With the move to software-defined wide-area networking (SD-WAN), branches are now directly connected to the internet, bringing security to the forefront. The remote nature of branches makes security inherently challenging. Often there is reduced visibility and direct knowledge, not only about what is happening on the branch network but even simply who and what devices are connecting to it.From branch employees to Internet-of-Things (IoT) devices that are being used to digitally transform the business, cyber criminals have plenty of targets. But branches often have little to no dedicated on-site IT staff who can investigate when something suspicious occurs. As threats continue to evolve and target the lowest-hanging fruit, weakly secured branches can serve as an easy entry point into the larger corporate system. Branch security needs to be a priority as branch locations are now far more vulnerable than they were in the past.Many SD-Branch solutions focus on consolidation and ease of management (both important characteristics), but thedependability of a branch’s network is directly related to its security. This means reliable security must be a top consideration of SD-Branch deployments.WAN EdgeThe rise of SD-WAN has completely changed how branch traffic is routed. With SD-WAN, traffic no longer travels back to corporate for security. Instead, to give the best quality of experience (QoE), traffic will often be routed to the internet directly at the branch. Therefore, SD-Branch solutions must inspect all traffic entering and exiting the branch, most particularlythose involving internet sources. To make matters worse, with the move to secure web-based Software-as-a-Service (SaaS)POINT OF VIEW 1POINT OF VIEW | Security Is the Key to a Dependable SD-Branch Solutionsolutions, more and more traffic is encrypted. Not only does this traffic need to be inspected, but it also requires decryption beforehand, then reencryption. All this needs to occur without impacting the QoE that SD-WAN has been installed for. Without fast and secure analysis of all traffic (encrypted or decrypted), performance will suffer, either from the need to route packets back to HQ for inspection, or from slow decryption/inspection.LAN EdgeWhile the internet presents one class of risk to a branch, the local-area network (LAN) layer (where users and guests connect) presents another. Bad actors try to access branch resources and launch greater attacks to the larger networkvia the LAN. The larger the number of branches (and fewer IT staff to cover them), the more important it becomes to have reliable, consistent, and pervasive security at the branch. LAN security needs to be tied into a larger security context to ensure that the network continues to operate at peak efficiency.Breach locations and attack methods are not predicable, so policies and settings across deployments need to be automated and enforced as close to the point of access as possible. Branch security needs to take into account that in addition to outside threats, the organization’s users are a potential problem. They may unwittingly compromise their machine either at the branch or while away, so the LAN must also be protected. SD-Branch security solutions need a tight coupling of all equipment at the branch.Being constantly vigilant for indications of compromise on user devices and directly quarantining threats where they enter the network are also necessary. Integrated branch security will keep the network safe from breaches entering through endpoint devices, ensuring operations continue smoothly regardless of attack attempts.IoT Device EdgeThe rising use of IoT devices within branches to drive important business outcomes has created a new issue that SD-Branch solutions must address. These devices are often highly vulnerable, lacking the security measures that higher-end client devices are capable of. Special care needs to be taken to secure IoT devices so they are not leveraged to launch an attack. The volume of IoT devices, and the varied solution sets they look to address, adds an additional level of challenge, as IT staff rarely has direct interaction with every device that is being brought online in any given branch.Flexible and automated branch security is needed to remove IT from the critical path of deployment for these technologies. Solutions that require manual intervention slow down business initiatives at the branch and impact overall performance. Instead, SD-Branch equipment must be able to securely onboard these devices, allowing operations to continue without unduly exposing the network.For Optimal Performance, SD-Branch Must Converge Around SecurityAbove all else, SD-Branch solutions are deployed to improve overall performance at the branch. While manageability may account for the more obvious return-on-investment (ROI) benefits of SD-Branch, without security, branch operations can slow or even grind to a halt. A reliable SD-Branch solution needs to offer security—not as a mere add-on—but integrated into all equipment to best address all aspects of branch dependability. By leveraging security at the heart of SD-Branch, the WAN, LAN, and device/IoT edge are all kept to optimal performance. Converging SD-Branch components with security enables a common framework for all branch network components, driving the best ROI. Copyright © 2021 Fortinet, Inc. All rights reserved. Fortinet, FortiGate, FortiCare and FortiGuard, and certain other marks are registered trademarks of Fortinet, Inc., and other Fortinet names herein may also be registered and/or common law trademarks of Fortinet. All other product or company names may be trademarks of their respective owners. Performance and other metrics contained herein were attained in internal lab tests under ideal conditions, and actual performance and other results may vary. Network variables, different network environments and other conditions may affect performance results. Nothing herein represents any binding commitment by Fortinet, and Fortinet disclaims all warranties, whether express or implied, except to the extent Fortinet enters a binding written contract, signed by Fortinet’s General Counsel, with a purchaser that expressly warrants that the identified product will perform according to certain expressly-identified performance metrics and, in such event, only the specific performance metrics expressly identified in such binding written contract shall be binding on Fortinet. For absolute clarity, any such warranty will be limited to performance in the same ideal conditions as in Fortinet’s internal lab tests. Fortinet disclaims in full any covenants, representations, and guarantees pursuant hereto, whether express or implied. Fortinet reserves the right to change, modify, transfer, or otherwise revise this publication without notice, and the most current version of the publication shall be applicable.March 31, 2021 1:58 AMD:\Fortinet\2021 Rebranded templates\POV\March\SD-Branch\pov-FA-security-to-a-dependable-sdbranch-solution-3302021\pov-FA-security-to-a-dependable-sdbranch-solution-3302021940960-0-0-EN。

硅砂的英文资料

Silica/QuartzMichel DumontThe author is with the Minerals and Metals Sector, Natural Resources Canada.Telephone: 613-995-2917E-mail: mdumont@nrcan.gc.caQ uartz (i.e., SiO2, also referred to as silicon dioxide orsilica) is one of the most common minerals on the face of the earth with numerous uses. It is produced and consumed in most countries. Annual world production of silica is estimated at 120-150 Mt.Quartz is not the only mineral composed of SiO2. There are eight other known structures composed of SiO2. They are polymorphs of silicon dioxide and belong to an informal group called the Quartz Group or Silica Group.S UMMARYIn Canada, silica is recovered in: a) lump form for use as metallurgical ﬂ ux and in the manufacture of silicon and ferrosilicon alloys; b) as sand for glass and glass ﬁ bre manufacture, foundry moulding, silicate chemicals, silicon chips, and optical ﬁ bres; and c) as ﬁ nely ground silica ﬂ our for ceramics, chrysotile cement, and concrete products (Table 4).Although Canada is self-sufﬁ cient for most of its silica requirements, signiﬁ cant tonnages of high-quality sand for glass and foundry applications are imported from the United States, mainly by Ontario. As a result of wide-spread availability and low prices, trade is restricted to con-venient cross-border shipments. However, silica with the desired speciﬁ cations for speciﬁ c applications may be shipped to large, distant markets.Preliminary data reported by users (Table 3) in Canada show that silica use was almost 2.6 Mt in 2005, a decrease of 66 255 t from the previous year. Preliminary data (Table 1) reported by Canadian producers for 2006 indicate production was valued at $64.8 million, a $5.1 million increase from 2005, reﬂ ecting the increase in shipments to 1.9 Mt from 1.8 Mt in 2005. Preliminary imports were val-ued at $105.4 million for 2006, an $8.3 million increase from 2005, with the tonnage for imports increasing to2.1 Mt from 1.7 Mt. Preliminary exports for 2006 were valued at $29.0 million, an increase of $2.4 million com-pared to 2005, even though the quantity decreased to373 669 t from 617 235 t.Preliminary data for 2005 (Table 3)1 show that the nonfer-rous smelting and reﬁ ning industry represents 33.5% of the total use of silica in Canada, a decrease of 3.2% from 2004. The primary glass and glass containers, and glass ﬁ bre wool sectors represented 19.5% of total use, an increase of 1.3% from 2004. Foundries, which represented 8.5% of the total use of silica in Canada, decreased 3.9% compared to 2004. Silica use by the chemicals industry represented 3.0% of the total use of silica in Canada, a 2.9% decrease compared to 2004. The use of silica in the cement industry represented 21.0%, but it also suffered a 2.6% decrease compared to 2004. The “other products” category repre-sented 14.5% of total use, a 4.8% decrease compared to 2004.With respect to the reported quantity of silica used by category (Table 4), sand represents 68.6% (1.8 Mt) of the total, a decrease of 42 863 t from 2004. For lump silica, which represents 28.9% (742 573 t) of the total, a slight decrease of 11 299 t from 2004 was observed. Preliminary data for silica ﬂ our, which represents 2.5% (64 963 t) of the total, indicate a decrease of 12 093 t from 2004.O CCURRENCESilica occurs mainly as the mineral quartz. Quartz occurs in many forms, the common being vein and massive intru-sive bodies, silica sand, sandstone, and quartzite. Quartz also occurs as crystals and as masses or aggregates in igneous rocks such as granites or pegmatites. Amorphous, non-crystalline varieties of quartz are less common and include opal, ﬂ int, chalcedony, tripoli, and diatomaceous earth.Although all occurrences of silica are of interest from a geological point of view, commercial interest and develop-ment are usually restricted to vein or intrusive deposits and to silica sand, sandstone, and quartzite deposits. Vein and intrusive deposits are igneous in origin and vary widely in47.2 CANADIAN MINERALS YEARBOOK, 2006P RODUCTION AND M ARKET C ONSIDERATIONSThe economics of the production and sale of the many types of silica are governed by many factors, but world demand for silica is controlled mostly by the fortunes of the glass and foundry industries. Throughout North America, the silica sand industry is highly competitive and the indus-try is dominated by a few large producers. A silica sand source location close to its users is important due to trans-portation cost considerations and, thus, silica is shipped only to local or regional markets. Bene ﬁ ciation is the key to producing high-quality glass or foundry sand from most deposits.The diverse uses of silica and quartz complicate market demand analysis. In the glass sector, construction and automobile markets drive ﬂ at glass sales, new construction being the basis for ﬁ breglass sales. These markets aredriven by the Gross Domestic Product. Silica sand demand in container glass is in ﬂ uenced by: reductions in the num-ber of consumption points through industry rationalization; decreased production as a result of strong competition from PET bottles (i.e., made of virgin resin of polyethylene terephthalate), aluminum, and paper containers; and increasing and mandated recycling rates in the glass con-tainer industry. Use in foundry applications depends on metal production (depending upon automobile sales, etc.) combined with recycling ef ﬁ ciencies and competitive sands. Hydraulic fracturing sand demand is in ﬂ uenced by the price of oil, regional oil production factors such as ﬂ ow rate and pressure, and changes in drilling technologies.S UPPLYSilica deposits of commercial interest occur in all10 provinces. The important Canadian production sites are discussed below. The provinces of Quebec, Ontario, and Alberta are the main producers of silica, followed bySaskatchewan, British Columbia, and Nova Scotia. Gener-ally, silica is extracted in open pits or by dredging.Newfoundland and LabradorShabogamo Mining and Exploration Co. Ltd. began mining its Roy’s Knob quartzite deposit near Labrador City inOctober 1999. The company’s washing and screening plant is located in Wabush, Labrador. The quartzite product is sent by rail to Sept-Îles, Quebec. Shabogamo supplies quartzite to Silicium de Bécancour Inc. of Quebec, which uses the material to manufacture silicon metal.Prince Edward IslandThere are no silica quarries currently in operation.shape and size. Such deposits are widespread throughout Canada. The quartz usually varies from white to grey and is relatively free of impurities.Silica sand has a high silica content (95% SiO 2 or more). The silica or quartz particles, derived from the mechanical disintegration and chemical decomposition of siliceous rocks, have been selectively sorted and concentrated by the action of wind or water during transport to new locations where they accumulated to form high-grade deposits.Sandstone is a sedimentary rock composed of quartz grains cemented by a bonding mineral. Sandstones, in which the bonding material is clay, calcite or iron oxide, are usually quite friable and easily reduced to grain size. Others may be more ﬁ rmly cemented by a siliceous cement and thus are more dif ﬁ cult to reduce to grain size. Most sandstones are white, grey or brown and usually contain varying amounts of mineral impurities, e.g., feldspar, hornblende, magnetite, pyrite, iron oxide stain, and mica.Quartzite is a hard, compact, metamorphosed sandstone composed of grains of quartz ﬁ rmly bonded with a sili-ceous cement. The original quartz grains, having coalesced with the siliceous cement to form a continuous homogen-eous mass, are not apparent to the naked eye.T RADEImports for 2006 (Table 1) from the United Statesaccounted for 98.1% of all imports (over 2.0 Mt). Imports of silica sands and quartz sands from the United Stateshave increased 21.4% (361 155 t) from 2005. Imports from the United States come from loosely consolidated and easily processed sandstone or lake sand deposits located near the Great Lakes. Major U.S. operations are located in the states of Illinois, Wisconsin, Michigan, and Indiana. Canada is the leading recipient (source: U.S. Geological Survey [USGS]) of U.S. exports (73%).Combined 2006 imports from the foundry and glass indus-try totaled almost 1.3 Mt. The tonnage of imports by the foundry industry increased by 33.4% from 2005 to 2006. Demand for foundry sand is dependent mainly on auto-mobile and light truck production. The tonnage of imports by the glass manufacturing industry increased by 6.9% from 2005 to 2006.Preliminary data for 2006 indicate that Canada’s exports (Table 1) of silica totaled 373 669 t, a decrease of 39.5% from 2005. The value of these exports totaled over$29.0 million, a 9.2% increase compared to the 2005 value of over $26.5 million. Of the total exports from Canada, 368 726 t (94.7%) went to the United States.SILICA/QUARTZ 47.3has the capacity to produce 50 000 t/y of chemical silicon, electronics-grade silicon metal, and specialty ferrosilicon. Although hampered by a furnace problem at its plant and a strike at its rail carrier (CN), it intends to construct a 3600-t/y facility for the production of solar-grade silicon metal. The company also sells silica fume to the construc-tion industry. In addition, it owns a quartzite deposit north of La Malbaie that is being developed by Sitec Inc. Sitec Inc. is a joint venture between Baskatong Quartz Inc. and SOQUEM Inc. Sitec mines and processes high-purity quartz for a range of end uses, including silicon metal and silicon carbide. The company also operates a custom crushing, drying, and screening plant in Shawinigan, Quebec.La Compagnie Bon Sable Ltée mines silica sand at Saint-Joseph-du-Lac and Ormstown. The material is used mainly for sandblasting and as a concrete sand; it is also suitable for the production of ﬁ breglass.Silco Sands Inc. mines and grinds silica at its plant inSainte-Clotilde-de-Châteauguay. The products are sold to a chemical company, a cement plant, and a ferromanganese plant.Temisca Inc., a division of Opta Minerals Inc., mines and processes silica near Saint-Bruno-de-Guigues for the golf course, ﬁ ltration sand, hydraulic fracturing (frac), abra-sives, and construction markets. The processing facility includes a 200 000-t/y hydrosizer, as well as screening, drying, and packaging equipment.Béton provincial ltée operates a silica sandstone quarry in Gaspé’s La Rivière County and Société Minière Gerdin Inc. operates a silica sand quarry on a seasonal basis in Saint-Rémi-d’Amherst.Exploration Québec/Labrador (EQL) Inc. mines its quartz deposit from Lac Daviault, near Fermont. Production is crushed on site, but is processed at the Granirex plant(division of DuPont Canada of Ontario) in Thetford Mines, Quebec, for the manufacturing of decorative and durable engineered stone products used in decorative surface appli-cations. EQL is planning to explore other markets for the quartz, including silicon metal.OntarioUnimin Canada Ltd. is also the largest producer of silica in Ontario with a capacity of about 500 000 t/y. Lump quartz-ite from Badgeley Island (150 000-t/y capacity) in northern Georgian Bay is shipped by boat to Canadian destinations for the manufacture of ferrosilicon. The ﬁ ner material, pro-duced by grinding, is shipped to Unimin’s plant at Midland (400 000-t/y capacity), south of Georgian Bay, where it is further processed to a glass-grade silica sand and to silica ﬂ our for ceramic and other uses.Nova ScotiaShaw Resources Ltd., a member of The Shaw Group Limited, produces a high-purity (98.5-99.5%) silica from sand deposits located at Nine Mile River, Hants County, near Shubenacadie. In addition, ﬁ ne sand from its silica operation is bene ﬁ ciated to ﬂ int glass-grade material. Fine sand products are sold in the Maritimes, Quebec, and northeastern United States for use in sandblasting, ﬁ lter sand, traction sand, cement and concrete manufacturing, refractory and decorative sand, and as a ﬂ ux for base-metal smelters.Black Bull Resources Inc. still has no production or revenue mining at its White Rock quartz project inYarmouth County. The site is located 42 km northwest of the deep port of Shelburne. Reserves of 16.3 Mt of high-quality angular and bright white quartz have been esti-mated. The material would be aimed at ﬁ ve different spe-cialized markets: pool plaster aggregate, engineered stone, exterior insulation and ﬁ nishing systems (EIFS), landscape stone, and golf course sand.New BrunswickShaw Resources’ Chaleur Silica Ltd. – a division of The Shaw Group Limited currently operates the Bass River silica quarry, providing silica as ﬂ ux material to the nearby Belledune lead smelter and for use in cement manufacture. It also manufactures abrasive products using raw material from Nova Scotia, Ontario, and the United States. Since 1986, Atlantic Silica Inc. mines and processes a high-grade (+98%) silica deposit located 22 km southwest of Sussex near Cassidy Lake. The quartz pebbles have been used to produce silicon metal and decorative stone. The quartz sand has been marketed for use in sandblasting, sili-con carbide, nursery grit, cement powder, glass, golf course sand, smelter ﬂ ux sand, and ﬁ ltration sand. Most of it is used in eastern Canada, although some is shipped to the United States.QuebecUnimin Canada Ltd., a subsidiary of Unimin Corp. of the United States, is the largest producer of silica in the pro-vince. Silica is mined from a quartzite deposit at Saint-Donat-de-Montcalm and from a sandstone deposit at Saint-Canut. Silica from Saint-Donat is shipped and re ﬁ ned at the Saint-Canut plant near Montréal. The majority of the silica produced by Unimin originates from Saint-Canut where the ore is ground, screened, and bene ﬁ ciated by magnetic separation. Most of Unimin’s output is used in the production of glass containers, ﬂ at glass, and ﬁ breglass; it is also in the silicon carbide industries.Silicium Bécancour Inc. (now owned by Timminco Ltd. of Toronto) operates the silica plant in Bécancour. Its facility47.4 CANADIAN MINERALS YEARBOOK, 2006AlbertaSil Industrial Minerals Inc. of Edmonton produces silica sand from local sand dunes in the Bruderheim area. It also operates a silica processing facility near Edmonton. The silica is sold mainly for the manufacture of ﬁ breglass and as sandblasting material. Other uses are in foundry, ﬁ ltra-tion, fracturing, and railway traction applications. The company also produces silica ﬂ our by processing the silica sand through a ball mill. The ﬂ our is used in thermal insu-lating cement in the oil and gas industries.Cementec Industries Inc. of Calgary produces, among other unique and proprietary products, silica ﬂ our, silica fume, and sandblasting sand for use in the oil and gas and con-struction industries.Hexion Specialty Chemicals of Columbus, Ohio,announced plans (source: Blendon Information Services) to construct a plant in Alberta to produce resin-coated proppants 2 for use in the oil and gas industry. The 150 million-lb/y plant will be built in Sturgeon County.British ColumbiaHeemskirk Consolidated Ltd. of Australia (who purchased Dynatec Corp.’s western operations) mines a high-purity (99.5%) silica sand for diverse industrial applications (e.g., glass grade, foundry sand, additive in refractory cements and ceramics, and use as a functional ﬁ ller/extender for paints) at the Moberly mine in the Golden area. The friable sandstone is ground, screened, washed, dried, and separ-ated into several sizes at a plant near Golden. These differ-ent sizes are sold mainly as glass sand, but also as sand-blasting sand, foundry sand, ﬁ lter media sand, and golf course bunker sand. In 2006, Heemskirk Canada Ltd., a subsidiary of Heemskirk Consolidated Ltd., expects to ship 80 000 t of silica, mainly to Lavington, B.C.Lafarge Canada Inc. mines silica-alumina material from the Buse Lake deposit as feedstock for its Kamloops cement plant.P RICESPrices for actual transactions vary according to geographic region and will take into account the quantity purchased, application, colour, impurities, exact grade purchased, credit terms, and other parameters. Due to the unavailabi-lity of Canadian prices, the following price examples are provided to facilitate an understanding.According to the U.S. Geological Survey 3 (USGS 2005 Review ), the value of silica increased by about 7% between 2004 and 2005 (average value, free on board [f.o.b.] plant). The average price for sand ranged from US$6.75/t forCrystal Quartz Canada, located near Dryden in western Ontario, is the only lascas-grade silica producer in North America. It supplies lascas quartz to North American cultured quartz producers.Signi ﬁ cant amounts of silica are extracted by others across Ontario for use as ﬂ ux for base-metal ore smelting oper-ations in Timmins and Sudbury, for silicon metal produc-tion, for specialty brick production, and for decorative uses. Other Ontario producers are: Arriscraft International Inc. with its Elgin Quarry in Bastard Township; Rapier Resour-ces Inc. with its Deagle Township Quarry, west of Sudbury; Great White Minerals Ltd. with its Fripp Quarry, near Timmins; Northern Mining and Exploration Inc. with its Shaw Township Quarry, in Timmins; and Roseval Silica with its Penhorwood Township Quarry, also near Timmins.ManitobaThere are no known silica quarries currently in operation in Manitoba. Nevertheless, Gossan Resources Ltd. of Winnipeg has consolidated its land position at its Mani-gotagan silica property (source: Blendon Information Services) by acquiring two adjacent quarry leases. The expanded property now encompasses 274 ha. A composite of 19 samples from the property has been tested and yielded a silica content of 94.2%. Tests have also con-cluded that the silica meets metallurgical requirements and may potentially be used as frac sand in shallow gas wells.SaskatchewanHudbay Minerals Inc. (formerly Hudson Bay Mining and Smelting Co., Limited) produces silica in the Amisk Lake area of northern Saskatchewan and is the largest user of the province’s silica sand at its Flin Flon, Manitoba, smelter. Hudbay uses sand as a ﬂ uxing agent that, in the molten state, reacts with impurities in the copper concentrate to produce a slag. The slag, with some of the impurities, is drawn off, leaving matte, a crude form of metal that requires further processing.Red Deer Silica Inc. produces a small amount of silica, northeast of the village of Hudson Bay, for use in golf course bunkers, stucco sand, and sandblasting sand.In mid-2002, the mineral deposit of the Hanson Lake silica sand project was appropriated by Trican Well Services and Saskatchewan Opportunities Corporation (SOCO). The mineral dispositions have been optioned to Winn Bay Sand Ltd., a company af ﬁ liated with the Ochapwace FirstNation. Lonesome Prairie Sand and Gravel Ltd. is the con-tractor carrying out all quarrying operations. All process-ing takes place on site. The silica sand is used as frac sand, predominantly in the gas ﬁ elds in Saskatchewan. It is transported to Burstall, Saskatchewan, just west of the Great Sand Hills, where it is of ﬂ oaded. Customers pick up their orders from this site.SILICA/QUARTZ 47.5Other Uses : Lump quartz and quartzite are used as liningsin ball and tube mills, and as lining and packing for acid towers. Naturally occurring ﬂ int pebbles may be used as a grinding medium for nonmetallic ores.Silica Sand 4Glass and Glass Fibre : Naturally occurring quartz sands and sands produced by crushing quartz, quartzite, or sand-stone are used in the manufacture of glass, glass ﬁ bre, and fused silica ware. The silica content should be greater than 99% and the iron oxide content should be uniform and less than 0.025%.Other impurities such as alumina, lime and magnesia should be less than 0.15% each. Chromium, cobalt and titanium are undesirable and should be less than 2 or 3 ppm. Uniformity of grain size is important and sand should generally be between 600 and 100 μm in size with a minimum of coarse and ﬁ ne material.Silicon Carbide : Sand for silicon carbide manufacture should have a silica content of 99% and iron oxide and alumina should each be less than 0.1%; lime, magnesia and phosphorus are particularly objectionable. Although coarse-grained sand is preferred, ﬁ ner sands are used where coarser grades are not available. All sand should be plus 150 μm, with the bulk of the sand being minus 2.0 to plus 0.5 mm in size.Hydraulic Fracturing : Silica sand is used as a “propping agent” in the hydraulic fracturing of oil-bearing formations to improve the recovery of oil. The sand should be clean, dry, and have a high compressive strength. The silica content should be high and carbonates and other acid-consuming minerals should be low. The sand grains should be between 850 and 500 μm in size and well rounded to facilitate placement and provide maximum permeability. Foundry Moulding : Naturally occurring sand and sand produced by the reduction of sandstone to grain size are used extensively in the foundry industry for moulding pur-poses. The purity and size of sand used depend on the type of casting and on the particular foundry practice. Iron and steel foundry sands vary in grain size between 850 and 75 μm in closely sized fractions. American FoundrySociety (AFS) numbers vary between 55 and 65 μm, with the bulk of the sand being preferably on three adjacent sieves; a rounded grain shape is preferred. The silica con-tent should be high (99% SiO 2) with low aluminum, iron, sodium, and potassium oxides.Silicate Chemicals : Sand for the manufacture of sodium silicate and other chemicals should be of high purity. Sodium silicate requires a silica content of 99%, the alu-mina less than 1%, the combined lime and magnesia lessmetallurgical ﬂ ux to US$103.85/t for ground foundry sand. For gravel, prices ranged from US$9.29/t for non-metallurgical ﬂ ux to US$49.79/t for ﬁ ltration. U.S. produ-cer prices reported to the USGS for silica commonly ranged from several dollars per tonne to hundreds of dol-lars per tonne, and occasionally exceeded the US$1000/t level. In the United States, ground sand for foundry mold-ing and core, at US$103.85/t, had the highest value per tonne, followed by silica for swimming pool ﬁ lters, US$81.81/t; ground sand used as ﬁ llers for paint, putty and rubber at US$59.32/t; ground sand for ceramics, US$50.30/t; ground sand for scouring cleansers, US$47.96/t; silica for municipal water ﬁ ltration,US$46.02/t; sand for hydraulic fracturing, US$43.45/t; and ground sand for ﬁ breglass, US$40.81/t.M AJOR U SES AND S PECIFICATIONSSilica in the form of quartz, sand, sandstone, and quartzite is used in many applications. Uses may be subdivided on the basis of particle size requirements, e.g., lump silica, 2 or 3 mm to 15 cm or more in size; silica sand, 2 or 3 mm in size down to 75 μm; and silica ﬂ our, which is essentially minus 75 μm in size. Applications for the silica with gen-eral speci ﬁ cations are discussed under the three general size categories stated (CANMET, Summary Report No. 4: Silica ).Lump Silica 4Flux : Quartz, quartzite, and occasionally sandstone and sand are used as ﬂ uxes in smelting base-metal ores with low silica contents. The silica content of the ﬂ ux should be as high as possible, but a small percentage of impurities such as iron oxide and alumina can be tolerated. Size is generally minus 2.5 to 0.5 cm.Silicon Alloys : Quartz, quartzite, and well-cemented sand-stone are used in the manufacture of silicon, ferrosilicon, and other alloys of silicon. The silica content of ferrosili-con should be 98% and the total iron oxide and alumina less than 1.5%. Lime and magnesia should not exceed 0.20% each; phosphorous and arsenic should also be very low. Silicon metal manufacture requires a high-purity quartz grading 99.5% SiO 2 or better with less than 0.04% iron oxide and alumina. Size speci ﬁ cations vary between 5 and 10 cm.Silica Brick : Quartz and quartzite crushed to 2.5 mm are used in the manufacture of silica brick for high-temperature refractory furnace linings. The silica content should be a minimum of 95%, and iron oxide and alumina should each be less than 0.1%. Other impurities such as lime and mag-nesia should be low.47.6 CANADIAN MINERALS YEARBOOK, 2006require precise sizing and a high-purity product. Thus, fur-ther processing and bene ﬁ ciation are normally required to both size and upgrade the raw silica feed material.Further reduction of the silica to a speci ﬁ c size, e.g., minus 850 μm to plus 150 μm, must be carefully carried out to avoid introducing extraneous impurities such as mill iron and other contaminants, and care must be exercised to avoid over-grinding. Whole unfractured grains are pre-ferred in foundry moulding, and ﬁ nes are detrimental in both foundry and glass sand applications. Over-grinding is more dif ﬁ cult to control when the starting material is quartz or quartzite, which do not possess a well-de ﬁ ned granular structure such as when crushing a more weakly cemented friable sandstone. The choice of grinding unit is also important; for example, impact mills produce more frac-tured grains and ﬁ nes than jaw, cone, or roll crushers.Following reduction to the size required, various bene ﬁ cia-tion steps may be used to remove impurities, typically clay, feldspar, carbonates, and ferromagnesian minerals. Bene-ﬁ ciation can include one or more of the following:Screening to remove the coarse and fine fractions, which • usually contain a significant percentage of the total impurity;Magnetic separation to remove iron-bearing minerals;• Jigging or tabling to remove heavy minerals;• Attrition scrubbing and washing to remove clay and • slimes;Flotation to remove minerals that do not respond to • magnetic or gravity methods, e.g., feldspar and pyrite; and Acid leaching to further reduce iron and carbonate • minerals.H EALTH AND S AFETY C ONCERNSCrystalline silica is silicon dioxide (SiO 2). Most minedminerals contain some SiO 2. “Crystalline” refers to the orientation of SiO 2 molecules in a ﬁ xed pattern. The three most common crystalline forms of silica encountered in industry are quartz, tridymite, and cristobalite.Silicosis is a disabling, non-reversible, and sometimes fatal lung disease caused by overexposure to respirable crystal-line silica. Silicosis can be prevented when crystalline silica is used safely and appropriate precautions are taken. Silicosis is preventable if employers, workers, and health professionals work together to reduce exposures (source: U.S. Department of Labor, Occupational Safety & Health Administration). In the United States, any mineral product with a crystalline silica content of >0.05% (down from thethan 0.5%, and iron oxide less than 0.1%. All sand should be between 840 and 150 μm in size.Other Uses : Coarsely ground, closely sized quartz, quartz-ite, sandstone, and sand are used as abrasive grit forsandblasting purposes and for the manufacture of abrasives papers. Various grades of closely sized, round-grained sand are used in water ﬁ ltration plants as a ﬁ ltering medium. Silica sand is used as an additive in portland cement manufacture when the source cement is low in silica.Silica FlourSilica ﬂ our, formed by grinding quartz, quartzite, sand-stone, and sand to 75 μm and ﬁ ner, is used in the ceramic industry for enamel frits and pottery ﬂ int. It is also used in the manufacture of chrysotile cement and autoclave-cured concrete products, as an inert ﬁ ller/extender mineral in rubber and paints, and as an abrasive ingredient in soaps and scouring powders.M INING, P ROCESSING, AND B ENEFICIATIONMiningCommercial silica is obtained from vein quartz, sand, sand-stone, and quartzite deposits. Mining is usually by open-pit benching using standard quarrying methods. Following primary breakage, the rock is trucked to the mill site for further size reduction, processing, and bene ﬁ ciation.ProcessingSilica may be used in lump form, as sand, as a ﬁ nely ground powder, and as silica ﬂ our. Primary crushing of lump silica is readily accomplished by jaw and cone crush-ers, and secondary crushing is done by hammer or impact-type mills. Further reduction to sand size may be accom-plished by roll crusher or rod mill, and to ﬂ our size or ﬁ ner by ball, vibratory or jet-milling, or by attrition grinding in a “stirred” ball mill using small ceramic pebbles as grinding media.Following primary and secondary crushing, lump quartz, sandstone and quartzite for use as ﬂ ux in the manufacture of silicon and ferrosilicon, etc., must be screened to meet size speci ﬁ cations. Screening may result in minor upgrading through the removal of impure ﬁ nes, but such material is essentially used as quarried with no bene ﬁ cia-tion apart from sizing.Bene ﬁ ciationUses requiring silica in the form of sand or ﬂ our, e.g., glass, silicon carbide, foundry and chrysotile cement, usually。

algeria-malial-qaeda—boundweaponsseized

must precede any idea of continental government and that the regional eco-nomic blocs are stepping stones to inte-gration and should be strengthened ﬁrst.President Yoweri Museveni of Uganda led the charge against an immediate Union government and United States of Africa in a heated debate on Febru-ary3rd,condemning it as impractical and damaging to African security. South Africa said the idea was imprac-tical and a threat to sovereignty.Presi-dent Museveni also disagreed on the involvement of traditional leaders by Col Gaddafy in his pursuit of the Uni-ted States of Africa dream.He accused Gaddafy of trying to use them as a political force against legitimate gov-ernments,and said he would arrest any traditional leader in Uganda claiming to speak for Gaddafy.Not mincing his words,Museveni said he would not trust the Libyan leader to represent Africa at the G20summit in London. In response to this concern,the AU leaders decided that a troika of Gad-dafy,Museveni and Tanzania’s Jakaya Kikwete should represent Africa at the London meeting.The previous AU summit in Egypt in July2008produced a skeleton agree-ment and theﬁrst day of the current meeting in Ethiopia was devoted to the union proposal.The chairman of the AU Commission, Gabon’s Jean Ping,had hoped to avoid disruption to the main business of the summit by devoting a whole day to Gaddafy’s unity plan.But he failed and the new chairman restarted talks on the4th when many heads of state had left.Later,after more deliberations,Gad-dafy called a press conference claiming absolute victory and that changing the name of the AU Commission to the AU Authority was theﬁrst irreversible step to pan-African government.He said the setting up of the Authority would accelerate Africa’s search for the ultimate political unity and strengthen Africa’s voice on global issues.‘‘In principle,we said the ultimate is a United States of Africa’’,Kikwete said,insisting the Authority would have a bigger mandate,bigger budget and‘‘bigger capacities’’than the exist-ing commission.But he was vague on how its powers would expand.The Tanzanian President said the Addis summit would agree by its close on the new authority’s structures but it would not be launched until the next summit in July.He said this would move the continent closer to a union government.The new authority would have a presi-dent and vice-president,and currentAU commissioner positions would betransformed into the secretaries of‘‘areas of shared competence’’includingpoverty reduction,infrastructure,dis-ease epidemics,peace and security andtransnational crime and terrorism.Mr Ping said recently that views on thespeed of integration varied from nineto35years,but the continent needed tospeak with a united voice to be heardin international negotiations on tradeand other issues including climatechange.The summit was not only taken upwith unity discussions but also over-shadowed by political unrest in Mada-gascar(p17847).There was,though,some serious discussion on Somaliawith the new President Sheikh SharifSheikh Ahmed attending the openingceremony.Ping and outgoing AUchairman Jakaya Kikwete welcomedhim and he was given a round ofapplause.The unity debate also distracted atten-tion from the implications of theInternational Criminal Court(ICC)issue of a warrant for the arrest ofSudan’s President Omar HassanAhmed al Bashir for war crimes inDarfur.The leaders supported a planto delay the execution of the arrestwarrant and asked al Bashir to accepta team of lawyers from the AU andthe Arab League to help bring perpe-trators of the Darfur violence tojustice and aid in investigations there.United Nations(UN)Secretary-General Ban Ki-Moon distanced him-self from this move.Col Gaddafy said the Sudanese leadermust fully cooperate in the search for asolution to the Darfur crisis.In hisﬁrstwarning to the Sudanese leader,he saidthe Sudanese government must work tofully conform with the demands andaspirations of the AU.(Agence FrancePresse3⁄2;International Herald Tribune11⁄2;The Daily Monitor website,Kampala5⁄2;The Star,Johannesburg5⁄2;Reuters1⁄2;PANA,Addis Ababa4⁄2)Meanwhile The AU Commissioner forPeace and Security,Ramtane Lama-mra,and Stefano Manservisi,theDirector-general for Development ofthe European Union(EU),on Febru-ary2nd signed theﬁnancing agreementfor the new Africa Peace Facility(APF).The new APF will amount to€300m and will cover the period2008-2010.It will include an Early ResponseMechanism which will strengthen theﬂexibility and rapidity of the APFresponse.A statement said the signing‘‘marks anew milestone in the cooperationbetween the EU and the AU,particu-larly in the implementation of the jointAfrica-EU strategy adopted in Lisbon,Portugal,in December2007’’.(ENAwebsite,Addis Ababa2⁄2)Moratorium onexecutions p.17816IN BRIEFECOWAS:Oﬃcials from the ECOWASCommission and member states have agreedon measures to improve synergy among vari-ous institutions involved in the integrationprocess to enhance the level of implementa-tion of regional programmes,particularlythe control of small arms in West Africa.(PANA,Lagos14⁄2)IGAD:African leaders,members of theInter-Governmental Authority on Develop-ment(IGAD),have abandoned the hardlinestance against the Somali government fol-lowing the election of a new President,Sheikh Sharif Sheikh Ahmed.Ethiopian Prime Minister Meles Zenawi,who chairs the seven-member IGAD saidthe‘‘conﬂict had been resolved throughother means.’’(PANA,Addis Ababa14⁄2)POLITICALRELATIONSALGERIA–MALIAl-Qaeda—Bound WeaponsSeizedIslamic militants have forged newarms trafﬁcking links.Customs oﬃcials in Mali say they haveintercepted a large stash of weaponsdestined for Al-Qaeda’s north Africanwing,Al-Qaeda in the Islamic Maghreb,according to a report in Algerian news-paper El Khabar on February25th.The weapons seized on the24th at aroadblock included mortar bombs anda large quantity of machine guns andammunition the newspaper said,citinga senior Malian customs oﬃcial basedin the capital Bamako.It said the weapons,which were sentfrom Guinea,constituted‘‘a veritablewar arsenal’’.The smugglers told Mal-ian oﬃcials it was the third time theyhad transported weapons for the samecustomer.AQLIM,formerly known as the Sala-ﬁst Group for Preaching and Com-bat(GSPC),has claimed a series ofbombings and attacks in Algeria inrecent years.The group is based inmountainous areas east of Algiers but asouthern oﬀshoot vies with Touaregnomads for control of traﬃcking routesacross the Sahara.El Khabar quoted Touareg rebelspokesman Hama Sid Aissa as sayingContinental Alignments17850–Africa Research BulletinA B C ÓBlackwell Publishing Ltd.2009.his movement was aware that Islamic militants had forged new arms traf-ﬁcking links to the Malian capital Bamako.He said the Islamist rebel group had beenﬁnancing these networks using funds raised from the ransom of two Austrian tourists it abducted in Tunisia in2008and who were later freed in Mali.On the19th,al-Qaeda’s wing in North Africa published photographs on the Internet of four of six Western hos-tages—a Swiss couple,a German woman and a British man—it claims to have in its custody.It claimed in an audio tape aired on Al Jazeera that it had a Canadian UN envoy and his aide and four Western tourists who were kidnapped in the West African Sahara in December2008.Niger’s President Mamadou Tandja said in January that investigations indicated ‘‘terrorists’’had kidnapped UN envoy Robert Fowler and his aide Louis Guay who went missing in the country in December(Vol45,p.17801).A senior Malian military source involved in investigating the kidnapping of the four tourists in northern Mali said the al Qaeda-linked group was most likely to be holding them.(Reuters 19,25⁄2)A French news agency on February 20th quoted a Malian source as saying that al-Qaeda in the Islamic Maghreb had kidnapped the six westerners because two Mauritanian terrorists were still detained in an African Sahel country.Observers think that the for-mer GSPC’s Mauritanian members may be leaders of the smuggling networks of the Sahel region and they also believe that they are jailed in Mali.(Echorouk Online21⁄2)Kidnappings p.17843BURUNDI–RWANDA Illegals Rounded Up and ExpelledRecent deportations are not a sign of xenophobia,says the Public Secu-rity Minister.Human rights activists in Burundi have criticised the government for deporting hundreds of foreign nationals rounded up in the suburbs of Bujumbura,but the authorities say the police are only trying to curb crime.‘‘There is no xenophobia in Burundi’’, Public Security Minister Alain Guil-laume Bunyoni told reporters.‘‘National legislation and international conventions should be respected while accepting people to reside in Bur-undi.’’As of February1st,he said,about400foreign nationals had beendeported.The security operations in which‘‘for-eigners’’were rounded up took manyby surprise—especially given that Bur-undi is adapting its legislation to con-form to the requirements of the EastAfrican Community(EAC),a processwhich is supposed to encourage the freeﬂow of people and goods.On February2nd,159people weredeported from Burundi after a policeoperation in the Bujumbura suburb,Ci-bitoke.They included154from theDemocratic Republic of Congo,fourRwandans and a Tanzanian.In recent weeks,the police havebeen checking the IDs of people indiﬀerent suburbs of the capital.Thosefound without ID cards are sent to astadium where their countries oforigin are determined throughquestioning.Burundians found without ID cards areﬁned francs2,000(US$1.6)and sentback home,but foreign nationals areimmediately escorted to the border.Burundi has just emerged from years ofconﬂict which saw many of its ownpeople seeking refuge in neighbouringcountries.Tanzania and Rwanda have bothexpressed deep concern at Bujumbura’sactions.(UN Integrated Regional Informa-tion Networks,IRIN4⁄;Net Press,Bujumb-ura20⁄2)CHAD–SENEGALPressure for Habre´’s TrialBelgium’s attempts to force Senegalto prosecute the ex-President ofChad have been welcomed in Africaand elsewhere.Belgium hasﬁled a lawsuit at the Inter-national Court of Justice(ICJ)in TheHague to force Senegal to prosecuteHisse ne Habre,former president ofChad,for crimes against humanity.Mr Habre has been living in exile inSenegal since1990.He is accused oftorturing and killing opponents duringhis1982-1990rule.Five African and international humanrights organisations have hailed Bel-gium’s call to prevail on Senegal to tryor extradite former Chadian presidentHisse ne Habre to Belgium.‘‘This is a major step in the bid forHabre not to get away with hiscrimes’’,they said in a communiquemade available to PANA.According to the communique,Belgiumaccused Senegal of violating the UnitedNations Convention against tortureand other cruel treatments by refusingto try or extradite the former Chadiandictator.Belgium was also of the viewthat Senegal did not comply with itsobligation to hand over to the courtsindividuals accused of crimes againsthumanity.Belgium asked the ICJ to take mea-sures to ensure that Habre does notleave Senegal pending its ruling.Senegal made a number of arrange-ments for Mr Habre’s trial,namelythrough the reform of its judicial sys-tem,but the issue of theﬁnancing ofthe trial estimated at CFA F18bnremains a snag.(PANA,Dakar21⁄2)Habre trial Vol.45p.17672REFUGEESCentral African Republic–ChadMany refugees in eastern Chadare still traumatised by theirexperiences and not ready to returnhome.A team from the United Nations HighCommissioner for Refugees(UNHCR)has reached thousands of people whoﬂed violence in the Central AfricanRepublic(CAR)to a remote area ofsouth-eastern Chad.The UN has started registering the newarrivals and providing emergency aid,as some6,000civilians,mostly womenand children from CAR’s Rounga andSara tribes,have taken refuge in Chadsince December to escape rebel attacksand clashes between rebels and govern-ment forces.Agency staﬀare also assessing theimmediate needs of the new arrivals.‘‘We are awaiting a decision from theChadian Government on proposals tomove the new arrivals to a safer loca-tion with easier access for humanitarianagencies’’,Ron Redmond of the UN-HCR said,adding that the most likelysite for a new camp would be in AmTiman,almost300kilometres north ofDaha.He added that many refugees inter-viewed by UNHCR were still trauma-tised by their experiences and not readyto return to the CAR.Currently,the agency helps over50,000CAR refugees inﬁve camps insouthern Chad as well as12sites ineastern Chad housing250,000refugeesfrom Sudan’s war-torn Darfur region.In addition,more than160,000Chadians are uprooted within theircountry’s borders.February1st–28th2009Africa Research Bulletin–17851A B CÓBlackwell Publishing Ltd.2009.。

-I-ICSIDclauses解决投资争端国际中心条款IDA-eligiblecountry

147 ____________________________________________________________________________________- I -ICSID clauses解决投资争端国际中心条款IDA-eligible countryDeveloping country which is entitled to receive IDA credits because its per capita income is below the IDA norm.符合国际开发协会信贷条件的国家由于人均国民收入低于国际开发协会标准，因而有资格接受国际开发协会发放的信贷的发展中国家。

IDA flows*国际开发协会资金流动IDA management fee国际开发协会管理费IDA recipient国际开发协会受援国IDA reflowsPayments received by IDA in the form of reimbursements for credits made.国际开发协会资金回流指国际开发协会收到的、对已发放的信贷的偿还款项。

IDA's “free-funds”Funds provided to IDA in a freely convertible currency or in a member's currency if available for financing procurement in the territory of the member, if there is a reasonable expectation that such resources will be fully used for procurement in such territory during the disbursement period.国际开发协会“自由资金”（会员国）向国际开发协会提供的可自由兑换的货币或用于在该会员国领土内进行采购的会员国货币。

Fortinet SD-Branch安全分支网络边缘安全汇编说明书

Fortinet SD-Branch Secures the Network Edge at the BranchExecutive SummaryDigital transformation (DX) has made branch networks much more complex—and therefore vulnerable to attack. In response, many organizations have deployed multiple point products to address new threat exposures as they appear. But this approach further complicates branch infrastructures—adding greater cost, complexity, and vulnerability. To address these issues, branches should integrate networking and security capabilities across the WAN edge, access layer, and endpoints. The solution, Fortinet SD-Branch, consolidates the network access layer within a secure platform that provides visibility and security to the network and all devices that connect to it.Addressing an Expanding Attack SurfaceRapid adoption of DX technologies—including Internet-of-Things (IoT) devices, Software-as-a-Service (SaaS) applications, digital voice/video tools, and bring-your-own-device (BYOD) endpoints—has caused an increase in the number of network edges that need to be securedat a given branch. Both the networks themselves and the point solution security products used to protect branch infrastructure have become difficult and costly to manage.The rise of IoT in particular—from connected office appliances, to efficient lighting and climate controls, to employee-owned personal fitness products—represents many more devices coming onto the network, often with questionable security and unreliable visibility. Fortinet SD-Branch SolutionFortinet delivers a broad, integrated, and automated approach to network security at an unmatched price-performance ratio. Fortinet SD-Branch seamlessly expands to the new edges of the network and delivers unparalleled performance and reliability, while at the same time providing centralized control and visibility across the entire branch attack surface.SD-Branch consolidates networking and security capabilities into a single solution that provides seamless protection of distributed environments. It covers all critical branch exposures—from the WAN edge, to the branch access layer, to a full spectrum of endpoint devices. It extends Fortinet Secure SD-WAN capabilities across wired and wireless networks while simplifying branch infrastructure management.FortiGate NGFW Featuring Secure SD-WAN Recommended byNSS Labs3:nn Blocked 100% of evasionsand achieved 99.9% security effectivenessnn Industry-best total cost ofownership (TCO)—10x better than the competitionnn Highest quality of experience for VoIP and video applications among all solutions tested64% of IT decision-makers believe their organization’s SaaS adoption is outpacing their ability to secure it.1While more that 25% of cyberattacks will target IoT by 2020, less than 10% of IT security budgets will be spent to protectthese devices.2SOLUTION BRIEFFortinet SD-Branch offers several key differentiators over competitive options. First, it enables security-driven networking by using the FortiGate next-generation firewall (NGFW) and broader Fortinet Security Fabric architecture to extend security throughout the network access layer. This includes Fortinet solutions like FortiAP (secure wireless access points) as well as FortiSwitch with FortiLink (secure Ethernet). The FortiNAC network access control (NAC) adds visibility, detection, and control of IoT devices—along with the added ability to track anomaly detection via traffic analysis.4Fortinet SD-Branch also includes single-pane-of-glass management of security, network access, and SD-WAN. Our FortiManager solution enables extensible management at scale with zero-touch deployment. Its combined interface for security and networking helps to ease the burden on limited IT staff while minimizing TCO.1SOLUTION BRIEF | Fortinet SD-Branch Secures the Network Edge at the BranchCopyright © 2021 Fortinet, Inc. All rights reserved. Fortinet ®, FortiGate ®, FortiCare ® and FortiGuard ®, and certain other marks are registered trademarks of Fortinet, Inc., and other Fortinet names herein may also be registered and/or common law trademarks of Fortinet. All other product or company names may be trademarks of their respective owners. Performance and other metrics contained herein were attained in internal lab tests under ideal conditions, and actual performance and other results may vary. Network variables, different network environments and other conditions may affect performance results. Nothing herein represents any binding commitment by Fortinet, and Fortinet disclaims all warranties, whether express or implied, except to the extent Fortinet enters a binding written contract, signed by Fortinet’s General Counsel, with a purchaser that expressly warrants that the identified product will perform according to certain expressly-identified performance metrics and, in such event, only the specific performance metrics expressly identified in such binding written contract shall be binding on Fortinet. For absolute clarity, any such warranty will be limited to performance in the same ideal conditions as in Fortinet’s internal lab tests. Fortinet disclaims in full any covenants, representations, and guarantees pursuant hereto, whether express or implied. Fortinet reserves the right to change, modify, transfer, or otherwise revise this publication without notice, and the most current version of the publication shall be applicable.September 14, 2021 6:31 AM431530-A-0-EN Fortinet SD-Branch Benefits for Network Engineering and Operations LeadersThe lead benefits of the Fortinet SD-Branch solution come from improving security at the branch. Global policies are enforced at all WAN edges, at the branch access layer, and across all endpoint devices. It extends both security and network performance to the access layer by unifying WAN and LAN environments. It automates discovery, classification, and security of IoT devices when they seek network access. It also automatically provides anomaly detection and remediation processes based on defined business logic. Finally, it allows distributed organizations to rapidly scale their operations across new offices and geographic locations.Fortinet SD-Branch also helps to reduce the need for onsite resources, which lower TCO. SD-Branch integrates firewalls, switches, and APs into a single, consolidated solution. Its single-pane-of-glass management capabilities combine security and network layer visibility to optimize staff efficiency while enabling proactive risk management. Zero-touch deployment features reduce the burdens associated with initial setup and business growth over time.Defining a Security-driven Approach to Branch NetworkingThe continuing evolution of branch networks makes them a security challenge. Remote locations need their own defenses that conform to the unique risks they present. As a natural extension of the Fortinet Security Fabric, SD-Branch provides security-driven networking. In doing so, SD-Branch consolidates the network access layer within a secure platform that provides visibility and security to the network and all devices that connect to it.The worldwide SD-Branch market is estimated to reach $3.27 billion by 2023.5“The most compelling argument for SD-Branch is operational agility. IT organizations can rapidly deploy and provision a network branch-in-a-box solution for new locations.”6Security-driven Networking:n n Security not as an afterthoughtn n Built into the network from the startn n Part of an integratedplatform solutionFortiAP FortiGateInternetFortiSwitchLANWAN (DIA)SD-WAN Routing Stack NGFW Security Figure 1:Fortinet SD-Branch consolidates WAN and LAN infrastructures.1 Conner Forrest, “Businesses are adopting SaaS too fast to properly secure it ,” TechRepublic, April 10, 2018.2 “25% Of Cyberattacks Will Target IoT In 2020,” Retail TouchPoints, accessed March 21, 2019.3Nirav Shah, “Fortinet Secure SD-WAN Gives the Performance of a Lifetime, Recommended by NSS Labs ,” Fortinet, August 9, 2018.4Available with FortiNAC version 8.6 release.5 “Worldwide SD-Branch (Fixed Site, Mobile Office) Market 2018-2023 - Market is Estimated to Reach $3.27 Billion ,” PR Newswire, August 21, 2018.6Lee Doyle, “SD-Branch: What it is and why you’ll need it ,” Network World, January 23, 2018.。

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Computers and Chemical Engineering26(2002)617–630An accelerated Branch-and-Bound algorithm for assignmentproblems of utility systemsAlexandros M.Strouvalis a,Istvan Heckl b,Ferenc Friedler b,Antonis C.Kokossis c,*a Department of Process Integration,Uni6ersity of Manchester,Institute of Science and Technology,PO Box88,Manchester M601QD,UKb Department of Computer Science,Uni6ersity of Veszpre´m,Egyetem u.10,Veszpre´m H-8200,Hungaryc Department of Chemical and Process Engineering,School of Engineering in the En6ironment,Uni6ersity of Surrey,Guildford GU27XH,UKAbstractA methodology is proposed for implementing logic and engineering knowledge within a Branch-and-Bound algorithm and with a purpose to accelerate convergence.The development addresses assignment problems of utility networks with an emphasis on the optimal allocation of units for maintenance problems.Proposed criteria are presented to automatically tailor the solution strategy and fully customise the optimisation solver.Model and problem properties are exploited to reduce the solution space,prioritise the branching of nodes,calculate lower bounds,and prune inferior parts of the binary parisons with commercial MILP solvers demonstrate the signiﬁcant merits of customising the solution search engine to the particular solution space.Extraction of knowledge and analysis of operations is conceptually supported by the graphical environment of the Hardware Composites.©2002Published by Elsevier Science Ltd.Keywords:Turbine networks;Maintenance scheduling;Operational planning;MILP solvers;Hardware composites/locate/compchemeng1.IntroductionThe impact of Mathematical Programming provessigniﬁcant through a wide range of applications.Opera-tions Research groups developed and contributed con-siderable part of the available optimisation tools.Attheir best,they epitomise general theoretical,computa-tional and numerical knowledge in relevance to thedifferent classes of problems.Past methods have provedunable to capture application features automatically.Inthe absence of speciﬁc knowledge,the use of general-purpose heuristics remains the only venue to acceleratethe search and/or reduce the solution space.Consider-ing that optimisation technology is a natural extensionof simulation—now widely accepted in industry—itmight be instructive to recall that simulation earnedacceptance and credit only with the use of customisedalgorithms(c.f.the inside-out algorithm for distilla-tion).In a similar vane,optimisation solvers shouldmake an effort to systematically incorporate probleminformation.In the case of MILP’s,the efﬁciency of aBranch-and-Bound algorithm is affected by the nodebranching criteria(Geoffrion&Marsten,1972;Parker&Rardin,1988;Floudas,1995).In the absence ofspeciﬁc knowledge,the use of general search rules cannot guarantee performance tantamount to the difﬁcultyor the actual size of the problem.Aﬁrst major contribution to exploit problem logicinvolved the modelling stage.Floudas and Grossmann(1995)reviewed methods for reducing the combinato-rial complexity of discrete problems using logic-basedmodels.Raman and Grossmann(1992)reported im-provements in solving MINLP’s with a combined use oflogic and heuristics.They illustrated their ideas withinference logic for the branching of the decision vari-ables(1993),and studied the use of logical disjunctionsas mixed-integer constraints(1994).Turkay and Gross-mann(1996)extended the application of logic disjunc-tions to MINLP’s using logic-based versions of OA andGBD algorithms.Hooker,Yan,Grossmann and Ra-man(1994)applied logic cuts to decrease the number ofnodes in MILP process networks models.Friedler,Tarjan,Huang and Fan(1992)illustrated the potentialfor dramatic reductions in the solution space.Friedler, *Corresponding author.Tel.:+44-1483-300800;fax:+44-1483-686581.E-mail address:a.kokossis@(A.C.Kokossis).0098-1354/02/$-see front matter©2002Published by Elsevier Science Ltd.PII:S0098-1354(01)00788-8A.M.Strou6alis et al./Computers and Chemical Engineering26(2002)617–630 618Varga and Fan(1995)later introduced a decision map-ping approach that is particularly efﬁcient for process synthesis applications.Vecchietti and Grossmann (1999)discussed the development of a solver(LOG-MIP)for solving disjunctive,algebraic MINLP or hy-brid non-linear optimisation problems.They later, (2000)presented a modelling language to set up the disjunctions and logical constraints.Lee and Gross-mann(2000)proposed a non-linear relaxation of the Generalised Disjunctive Programming and developed a special Branch-and-Bound algorithm that makes use of information of the relaxed problem to decide on the branching of terms of disjunctions.The present work explains the integration of knowl-edge at a more advanced level:the solution search engine.The problem structure is exploited to prioritise and co-ordinate the optimisation search.A Customised Branch-and-Bound Solver(B&B)is developed to incor-porate conceptual information.The approach reports signiﬁcant reductions in the computational effort and supplements the work of Strouvalis,Heckl,Friedler and Kokossis(2000).The methodology makes use of Hardware Composites,(Mavromatis&Kokossis, 1998a,b,c;Strouvalis,Mavromatis&Kokossis,1998). The tool supports the customisation of the algorithm, provides insights of utility operations and promotes the understanding of results.2.Assignment problems and optimisation challenges The problem taken into account deals with the as-signment of units to shut-down periods.The appropri-ate sequence of switching off turbines and boilers for preventive maintenance contributes to the reliability, availability and proﬁtability of the entire system.Each period relates to either a single or multiple sets of constant demands in power and process heat.Optimal scheduling assumes meeting demands and maintenance needs while minimising the operational cost.Switching off units imposes penalties to the economic perfor-mance of the network.As less efﬁcient units are loaded or power is purchased from grid to compensate for the ones maintained,optimisation has to consider demand variations over time,differences in the efﬁciencies of units and feasibility aspects.Formulations yield MILP problems with a consider-able number of variables.Constraints are linear and binary variables are assigned for the ON/OFF status of units.Planning and Scheduling Problems of large-scale networks are computationally expensive or even in-tractable.This is due to the exponential growth of combinatorial load with the number of periods and units.Conventional approaches suggest the formulation of efﬁcient models solved by standard commercial opti-misation platforms.Even for moderate networks,how-ever,the problem assumes prohibitive dimensions. Furthermore,due to minor differences in nearby solu-tions,the Branch-and-Bound trees are generallyﬂat and difﬁcult to fathom.General-purpose solvers are unable to capitalise on available information out of the general-purpose tuning,bounding and pruning frame-work they employ.Therefore,there is scope for efﬁcient optimisation tools customised to the particular application.3.Development of the Branch-and-Bound algorithm The problem domain consists of three major compo-nents:utility network,demands,and maintenance re-quirements.Efﬁciencies and layout of units,operational costs,and constraints set up the network component. Theﬂuctuating pattern of demands is a parameter of the problem along with the maintenance needs of each turbine and boiler.The problem domain is researched to deﬁne and prioritise the solution space and thus customise the algorithm.Conceptual analysis,feasibil-ity assessment of maintenance scenarios,and cost as-sessment of basic maintenance scenarios are employed to preprocess the space.Conceptual analysis is achieved by plotting demands on the Hardware Composites and understanding the role of units over time.A set of LP’s are solved toﬁnd infeasible options and objective func-tion values of modes corresponding to the shut-down of individual units in all possible periods.A standard B&B algorithm(i.e.Dakin,1965;Flou-das,1995)is shown in Fig.1(a)and consists of six major steps:(i)initialisation,(ii)termination,(iii)selec-tion of candidate subproblem,(iv)relaxation(bound-ing),(v)pruning and(vi)separation(branching).The proposed customisation spans over the four main stages (highlighted boxes in Fig.1(b)):candidate problem selection,bounding,branching and pruning.Special additional functions identify(mark)and exclude (delete)inferior nodes that should not be enumerated. The contributions are at two levels.(i)The conceptual analysis of the problem and theassignment of priorities(period and unit).(ii)The tuning and customisation of the solver to the particular application.The reduction of the solution space is accomplished by screening out infeasible and redundant combinations of variables.Thisﬁrst level makes simple and straight-forward use of the engineering information and is re-ferred as the Preprocessing Stage.The second level constitutes a more reﬁned analysis of the knowledge. The basic idea is to replace general B&B rules by a number of criteria and functions to co-ordinate the branching and enhance the pruning.A.M.Strou6alis et al./Computers and Chemical Engineering26(2002)617–6306193.1.Solution space preprocessing3.1.1.Conceptual toolsThe Hardware Composites have been developed for representing the feasible and optimal space of steam turbine networks.Visualised solution spaces function as ‘maps’where demands are traced and corresponding turbine modes identiﬁed.The tool is based on the well-established Willans line(Church,1950;Kearton, 1958)which models the expansion of steam through cylinders.For a single turbine t(Fig.2(a)),inlet steam ﬂowrate MS t is given by:MS t=m t E+c t(1) where E is the turbine power output,m t the slope of the line associated with the expansion path efﬁciency and c t the no-load constant.Feasible modes locate on the Willans line.For a backpressure passout turbine(Fig.2(b))the second cylinder gives rise to an additional term ac-counting for the passoutﬂowrate and the associated power generation.The inlet steam consumption is given by the equation:MS t=m t E+1−m tg tS+ct(2)Fig.1.(a)Standard and(b)customised Branch-and-Bound algorithm.A .M .Strou 6alis et al ./Computers and Chemical Engineering 26(2002)617–630620Fig. 2.Willans lines for (a)single and (b)backpressure passout turbines.An alternative and equivalent representation is shown in Fig.3(b);the Hardware Composites are drawn with the power and passout steam as co-ordi-nates.This version allows for directly spotting sets of demands on the solution space and is mainly adopted in the present work.3.1.2.Assignment of prioritiesThe relative position of the demands and the units on the Hardware Composites determines favourable,unfa-vourable and impossible maintenance combinations.As units are switched off,the penalties imposed to theFig.3.Alternative Hardware Composites representations:(a)inlet steam vs.power output and (b)passout steam vs.power output.where S stands for the steam passout demand and g t is the Willans line slope associated with the high-pressure expansion path.A turbine capability diagram may be restrained by lines r t =(1−m t /g t )and p t =1/(1/m t −1/g t )corresponding to power and inlet steam capacities,respectively.Feasible operational modes are all inside the capability diagram.Operation of boilers and gas turbines is similarly de ﬁned by linear models presented in Appendix A.The application of Construction Rules of Mavroma-tis and Kokossis (1998b)resolves ef ﬁciency con ﬂicts and structures the optimal solution space of the entire turbine network.The rules impose full loading of the most ef ﬁcient expansion paths prior to less ef ﬁcient ones.Slopes m and g (incremental ef ﬁciencies)of the Willans lines de ﬁne the line sequence on the Hardware Composites.Objective is minimisation of the inlet steam consumption,or equivalently the cost of fuel burnt in the boiler house.Given the ef ﬁciencies and capacities of turbines (ca-pability diagrams)and boilers,the Hardware Com-posites of a network featuring three steam turbines and two boilers are shown in Fig.3(a).Any point on the Composites corresponds to unique set of demands and optimal mode.P ,for example,designates the network operation for meeting power e p and passout s p demands with the least steam requirement MS p .The path from the graph origin to P reveals the load of cylinders and depicts the role of units.The high-pressure cylinders of T 2(at full load)and T 1(supplementary)supply passout s p .The T 1low-pressure cylinder generates the remain-ing power output requirement of P .Dashed zones over the Hardware Composites denote operation of boilers and their steam generation capacities.Less fuel-con-suming boilers ﬁrst switch on to meet turbine inlet steam requirements.For greater ﬂowrates (upper-right part of solution space)additional boilers accommodate the demands.At P ,inlet steam MS p is entirely provided by Boiler 1.A.M.Strou6alis et al./Computers and Chemical Engineering26(2002)617–630621 objective function vary with the(i)unit efﬁciency,(ii)the efﬁciency of the units available to replace them and(iii)the demands of the particular period.Each periodis affected to a different extent and priorities are strongfunctions of the layout of demands.High priorities formaintenance options relate to minor alterations in theoperation of the utility network.Conceptual analysis(Strouvalis et al.(2000)),based on the Hardware Com-posites,provides knowledge and insights of the spaceand prioritises maintenance options.In addition to conceptual preprocessing,priorities areestablished computationally as well for the sake ofautomation.Associated with each period t T are lowerbounds corresponding to the(lowest)operating cost(objective function)that employs all units u U.Let theset of lower bounds,Cost oper={c Tt },over all periods nof the time horizon be:Cost oper={c Ttt=1,…,n}(3) For an idle u in period k a penalty p(u,T k)is assigned calculated by shutting down exactly u andevaluating the new objective value,C uTk .The penalty isgiven by:p(u,T k)=(C uTk −c Tk)(4)Let OS u pen be the ordered set of penalties in ascending order:OS u pen={(C uTt −c Tt) u U,t T}(5)Let OS u per deﬁne the prioritised periods for u from the penalty sequence in OS u pen:OS u per={T u i i=1,…,n}(6) where:T u1=T t(C uTt −c Tt)=mint TOS u pen(7)Period T u1has the highest priority,followed in OS u per by periods of decreasing priority.The periods for each u in OS u per are alternatively represented as T u k(u);T u1 corresponds to k(u)=1,T u2to k(u)=2,etc. Priorities over units are developed by calculating arithmetic averages P u aver over theﬁrst N(u)entries of the OS u pen.N(u)is deﬁned by the following heuristic: Let:a=N TA(8)(non-integer values are rounded to previous integer, with a]1))b(u)=number of periods in OS u per(9) N(u)=min{a,b(u)}(10) A is the weight parameter associated with the length of operating horizon.Theﬁrst N(u)penalties of OS u pen are used to provide the arithmetic average P u aver:P u aver=1N(u)%N(u)n=1p(u,T u n)(11)Penalties P u aver for units u sorted in descending order provide ordered set OS U:OS U={u i:P uiaver]P ujaver,Öj\i}(12) Let us represent the integer solution space by a matrix with rows SMR i that correspond to units and columns SMC j that relate to periods.The elements of the matrix are binary variables allocating maintenance periods.The prioritisation of periods and units(OS u per and OS U)deﬁnes the sequences SMR i over the columns and rows,respectively.The Solver Matrix of the solu-tion space is thus obtained by:SMR i=OS ujper:rank(OSU,u j)=i(13) Rows follow the sequence of units in OS U with periods ordered according to OS u per per row.3.2.Tuning of the sol6er3.2.1.Customised branchingEstablished priorities for periods and units encom-pass the knowledge of the particular utility network and variation of demands.Let us consider as Candidate List(CL)the running list of candidates for enumera-tion.The list includes nodes w=(T u1k(u1),Tu2k(u2),…,Tunk(u n)) that deﬁne speciﬁc subproblems(combination of binary variables assigning shut-down of units).Period T u1k(u1) corresponds to the maintenance of theﬁrst unit of OS U[Y u1T u1k(u1)=0],Tu2k(u2)is the maintenance period of u2[Y u2T u2k(u2)=0],etc.If a node does not involve a decision for the maintenance of a unit,symbol(X) deﬁnes the corresponding relaxation.In the customised solver(X)represents the exclusion of the maintenance requirements(constraints)of u at the speciﬁc enumer-ated node.Parent node w o=(X,X,…,X)represents the relaxed subproblem where no unit maintenance is as-signed to any period.Node(T u1k(u1),Tu2k(u2),X,…,X)rep-resents the relaxed subproblem where theﬁrst two units in priority are allocated to maintenance periods with the rest assigned to no period.The bound value of node w is represented by B(w).Assume node w=(T u1k(u1),Tu2k(u2),…,Tumk(u m),X, (X)with the units in priority list OS U up to m switched off in periods T u1k(u1),Tu2k(u2),…,Tumk(u m),respectively.If T u1k(u1)"Tu2k(u2)"…"Tumk(u m),node w is called inde-pendent.An independent node includes independent periods.If at least two out of periods T u1k(u1),Tu2k(u2),…,Tumk(u m) are identical,node w is called dependent.The identi-cal periods are called dependent periods.A .M .Strou 6alis et al ./Computers and Chemical Engineering 26(2002)617–630622If node w is infeasible,it is classi ﬁed as dependent with in ﬁnite bound.Based on the properties of dependent and indepen-dent nodes,bounds are determined by penalty valuesp (u n ,T u n k (u n ))according to the following Lemma.Lemma.Let a parent node :w =(T u 1k (u 1),T u 2k (u 2),…,T u mk (u m ),X ,…,X )and a child node :w %=(T u 1k (u 1),T u 2k (u 2),…,T u m k (u m ),T u nk (u n ),X ,…,X )(i)if w %is independent thenB (w %)=B (w )+p (u n ,T u nk (u n ))(14)(ii)if w %is dependent thenB (w %)]B (w )+p (u n ,T u nk (u n ))(15)If node w is terminal :B (w )=B (w 0)+%U Mi =1p (u i ,T u ik (u i ))(w independent)(16)B (w )]B (w 0)+%U Mi =1p (u i ,T u ik (u i ))(w dependent)(17)where U M is the total number of units subject to mainte -nance and w 0=(X ,X ,…,X ).Branching of nodes is handled by two criteria:theBranching Variable Selection [BVSC]and Candidate Problem Selection Criterion [CPSC].The scope of [BVSC]is to de ﬁne the membership of CL and the ordering of the subproblems in it.The [CPSC]is re-sponsible for executing the enumeration of the next node from the ones included in CL.3.2.1.1.Branching 6ariable selection criterion [BVSC ].The [BVSC]determines (i)the membership in the CL and (ii)the ordering of nodes in CL.This criterion uses sets OS U and OS u per .3.2.1.2.Candidate problem -node selection criterion [CPSC ].The Candidate Problem Selection Criterion [CPSC]has the task to select the next node for branch-ing out of the CL of nodes.The criterion adopts a Depth-First strategy with backtracking;the Last-In-First-Out (LIFO)selects a child from parent node,whereby,the last added to CL is the ﬁrst one to select.When a child node is pruned,backtracking of the parent node identi ﬁes other child nodes not yet enumer-ated.The (LIFO)criterion is chosen on the merits of requiring less candidate storage and calculation restarts than the Best-Bound alternative,as Parker and Rardin (1988)mention.The (LIFO)strategy implemented in astandard B&B,however,involves the solution ofgreater numbers of candidate subproblems.The cus-tomised pruning and bounding eliminate a signi ﬁcant portion of the explicitly visited nodes and overcome this drawback.3.2.2.Customised pruningStandard pruning disregards nodes with higher bounds (Fig.1(a)).The proposed enhanced pruning consists of two additional criteria:(i)Mark and (ii)Delete Criterion (Fig.1(b)).The ﬁrst ‘marks ’subprob-lems in relation to dependent nodes,while the second eliminates from CL the quali ﬁed for pruning nodes.Enhanced pruning exploits the properties of depen-dent and independent nodes.The methodology makes use of sets OS uper to select combinations and exclude redundant enumerations;nodes that follow independent nodes are pruned.For dependent nodes further branch-ing is required.3.2.2.1.Mark criterion [MC ].The Mark Criterion [MC]imposes the enumeration of nodes due to con ﬂicts in priorities.[MC]applies on any node w retrieved from the CL.For a general dependent node w =(T u 1k (u 1),…,T u n k (u n ),X ,…,X ),where periods T u 1k (u 1) T u n k (u n ),[MC]marks the nodes w 1=(T u 1k (u 1)+1,X ,…,X ),and w 2=(T u 1k (u 1),…,T u nk (u n )+1,X ,…,X )for enumeration.The number of marked nodes equals the number of dependent periods present in the dependent node.The same procedure is applied to units and periods of infeasible nodes.3.2.2.2.Delete criterion [DC ].The Delete Criterion is applied on terminal or pruned nodes and it removes from CL unmarked nodes.[DC]eliminates nodes start-ing from the end of the CL up to the point a marked node is found.The elimination then halts and enumera-tion of marked nodes is enforced.If no marked node is present [DC]eliminates the entire list.3.2.2.3.Theorems of customised pruning .Nodes w %quali ﬁed for enhanced pruning are de ﬁned by Theorem 1and Theorem 2.The ﬁrst de ﬁnes pruned subproblems associated to independent nodes while the second to dependent ones.Theorem 1.Let a terminal independent node :w 1=(T u 1k (u 1),T u 2k (u 2),…,T u nk (u n ))or a pruned independent node :w 2=(T u 1k (u 1),T u 2k (u 2),…,T u nk (u n ),X ,…,X )For e 6ery node :w %1=(T u 1k %(u 1),T u 2k %(u 2),…,T u nk %(u n ))orA .M .Strou 6alis et al ./Computers and Chemical Engineering 26(2002)617–630623w %2=(T u 1k %(u 1),T u 2k %(u 2),…,T u nk %(u n ),X ,…,X )with k %(u i )]k (u i ),Öi {1,…,n }it holds :B (w 1)5B (w %1)and B (w 2)5B (w %2)(18)Theorem 2.Let T u k k (u k ) T u j k (u j )on a terminal dependent node :w 1=(T u 1k (u 1),T u 2k (u 2),…,T u k k (u k ),…,T u j k (u j ),…,T u nk (u n ))or a pruned dependent node :w 2=(T u 1k (u 1),T u 2k (u 2),…,T u k k (u k ),…,T u jk (u j ),X ,…,X )For e 6ery node :w %1=(T u 1k %(u 1),T u 2k %(u 2),…,T u k k (u k ),…,T u j k (u j ),…,T u nk %(u n ))orw %2=(T u 1k %(u 1),T u 2k %(u 2),…,T u k k (u k ),…,T u jk (u j ),X ,…,X )with k %(u i )]k (u i ),Öi {1,…,n }it holds :B (w 1)5B (w %1)and B (w 2)5B (w %2)(19)Proofs of Theorem 1and Theorem 2are presented in Appendix B.3.2.3.Customised boundingThe accelerated algorithm bounds nodes by capitalis-ing on information of the Preprocessing Stage.Rather than calling the LP solver in every node for estimation of bounds (by ﬁxing branched variables to integer values and relaxing the remaining ones),a more re ﬁned policy of solving LP ’s is adopted.Independent node combinations relate to decoupled maintenance (mainte-nance of units in non-identical periods).These nodes are appropriate for having their bounds de ﬁned by already available values.Nodes,on the contrary,asso-ciated to coupled combinations need separate bounding and LP solution.As such the intelligent and restrained use of the LP solver reduces the resources spent on bounding.The approach includes:1.Selective processing of nodes,2.Selective processing of constraints.3.2.3.1.Selecti 6e processing of nodes .Customised bounding applies only to independent nodes.In this case the solution of separate LP ’s to develop bounds becomes redundant.Indeed,bounding only requires updates of bounds through straightforward calcula-tions.The approach makes use of the penalty valuesp (u i ,T u ik (u i ))to de ﬁne the bound increase during branch-ing.For dependent nodes,bounds follow conventionalprocedures.These nodes are bounded using the LPsolver.Overall,bounding makes a restricted use of the LP solver.The tightness of bounds is though relaxed,be-cause,some of the maintenance constraints are disre-garded;i.e.for the bound of w 1=(T 1,X ),maintenance constraints of the second unit are not considered.As the remaining (relaxed)maintenance constraints are not taken under consideration less tight lower bounds are obtained.3.2.3.2.Selecti 6e processing of constraints .Development of customised bounds is a combined application of a customised use of the LP solver and preprocessing information.In that perspective every subproblem must be examined disregarding all maintenance constraints of child nodes.This allows for decoupling decisions-constraints between parent and child nodes or equiva-lently between periods.In that manner calculation of bounds is permitted using values of the preprocessing.The LP solver addresses subproblems where all bi-nary variables are set to ﬁxed values.Maintenance constraints coupling periods are introduced at each branching level.Nodes not already branched have the corresponding unit maintenance constraints (and hence binary variables)excluded from the bound calculation of their parent nodes.This allows the examination of decoupled scenarios using already available bounds.Only coupled operations,where shut-down of units affects more than one periods,are examined by sepa-rate LP ’s.4.ImplementationThe customised Branch-and-Bound solver is imple-mented in C ++and uses LINX (Fabian,1992)as the LP solver.LINX is a simplex-based routine collection to facilitate special-purpose solvers and support the suc-cessive use of LP ’s in relevant sub-problems.The B&B solver features options for the implemented level of customisation.Options account for conventional B&B pruning or pruning based on [DC]and [MC].As usual,priorities can alternatively be set by users.5.Illustration5.1.Problem descriptionThe problem considers four steam turbines with the ef ﬁciencies of Table A1(Appendix A).The time hori-zon consists of four time periods.Maintenance requires one shut-down period per unit.Sets of data in power and heat (A ,B ,C ,D )are plotted on the Hardware Composites of the network (Fig.4).A .M .Strou 6alis et al ./Computers and Chemical Engineering 26(2002)617–630624Fig.4.The utility network and the hardware composites for illustration.Step I:Preprocessing of Solution Space(i)Preliminary Reduction of Solution Space The sets of maintenance periods are:M (TU 1)={A ,B ,C }M (TU 2)={A ,B ,C ,D }M (TU 3)={A ,B ,C ,D }M (TU 4)={A ,B ,C ,D }Operation of turbine TU 1is compulsory in D due to the high power demand.The large capacity of TU 1safeguards the feasible operation and ex-cludes period D from the set of possible mainte-nance periods M (TU 1)of TU 1.(ii)Period prioritisation:Values c T t are calculated foreach T t and shown in Table 1:Solution of 4×4=16LP ’s yields the operational costs C uT t of Table 2.Penalties p (u ,T t )=(C uT t −C T t )are then de ﬁned (each considering one unit off)as shown in Table 3:Sorted in as-cending order penalties p (u ,T t )determine sets OS u pen :OS TU 1pen ={4433.3,6022.2,6388.9}OS TU 2pen ={0,222.2,888.9,1333.3}OS TU 3pen ={55.6,83.3,166.6,222.2}OS TU 4pen ={0,0,0,0}Next,associated periods T t to penalties of OS upen provide the priority lists OS u per:OS TU 1per ={A ,C ,B }OS TU 2per ={A ,C ,B ,D }OS TU 3per ={B ,A ,D ,C }OS TU 4per={D ,C ,B ,A }Table 1Minimum operational cost c T t per T t for illustrationPeriod AB C D 26666.7c T t ($/period)21666.721111.127777.8Table 2Operational costs ($/period)of maintenance scenarios for illustrationPeriod D AC B Infeasible TU 126100275003380021666.722000TU 2280002800026833.3280002166.7TU 32175021666.721111.127777.826666.7TU 4。