英文文献及翻译计算机专业

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计算机专业外文文献翻译6

外文文献翻译（译成中文2000字左右）：As research laboratories become more automated,new problems are arising for laboratory managers.Rarely does a laboratory purchase all of its automation from a single equipment vendor. As a result,managers are forced to spend money training their users on numerous different software packages while purchasing support contracts for each. This suggests a problem of scalability. In the ideal world,managers could use the same software package to control systems of any size; from single instruments such as pipettors or readers to large robotic systems with up to hundreds of instruments. If such a software package existed, managers would only have to train users on one platform and would be able to source software support from a single vendor.If automation software is written to be scalable, it must also be flexible. Having a platform that can control systems of any size is far less valuable if the end user cannot control every device type they need to use. Similarly, if the software cannot connect to the customer’s Laboratory Information Management System (LIMS) database,it is of limited usefulness. The ideal automation software platform must therefore have an open architecture to provide such connectivity.Two strong reasons to automate a laboratory are increased throughput and improved robustness. It does not make sense to purchase high-speed automation if the controlling software does not maximize throughput of the system. The ideal automation software, therefore, would make use of redundant devices in the system to increase throughput. For example, let us assume that a plate-reading step is the slowest task in a given method. It would make that if the system operator connected another identical reader into the system, the controller software should be able to use both readers, cutting the total throughput time of the reading step in half. While resource pooling provides a clear throughput advantage, it can also be used to make the system more robust. For example, if one of the two readers were to experience some sort of error, the controlling software should be smart enough to route all samples to the working reader without taking the entire system offline.Now that one embodiment of an ideal automation control platform has been described let us see how the use of C++ helps achieving this ideal possible.DISCUSSIONC++: An Object-Oriented LanguageDeveloped in 1983 by BjarneStroustrup of Bell Labs,C++ helped propel the concept of object-oriented programming into the mainstream.The term ‘‘object-oriented programming language’’ is a familiar phrase that has been in use for decades. But what does it mean? And why is it relevant for automation software? Essentially, a language that is object-oriented provides three important programming mechanisms:encapsulation, inheritance, and polymorphism.Encapsulation is the ability of an object to maintain its own methods (or functions) and properties (or variables).For example, an ‘‘engine’’ object might contain methods for starting, stopping, or accelerating, along with properties for ‘‘RPM’’ and ‘‘Oil pressure’’. Further, encapsulation allows an object to hide private data from a ny entity outside the object. The programmer can control access to the object’s data by marking methods or properties as public, protected,or private. This access control helps abstract away the inner workings of a class while making it obvious to a caller which methods and properties are intended to be used externally.Inheritance allows one object to be a superset of another object. For example, one can create an object called Automobile that inherits from Vehicle. The Automobile object has access to all non-private methods and properties of Vehicle plus any additional methods or properties that makes it uniquely an automobile.Polymorphism is an extremely powerful mechanism that allows various inherited objects to exhibit different behaviors when the same named method is invoked upon them. For example, let us say our Vehicle object contains a method called CountWheels. When we invoke this method on our Automobile, we learn that the Automobile has four wheels.However, when we call this method on an object called Bus,we find that the Bus has 10 wheels.Together, encapsulation, inheritance, and polymorphism help promote code reuse, which is essential to meeting our requirement that the software package be flexible. A vendor can build up a comprehensive library of objects (a serial communications class, a state machine class, a device driver class,etc.) that can be reused across many different code modules.A typical control software vendor might have 100 device drivers. It would be a nightmare if for each of these drivers there were no building blocks for graphical user interface (GUI) or communications to build on. By building and maintaining a library of foundation objects, the vendor will save countless hours of programming and debugging time.All three tenets of object-oriented programming are leveraged by the use of interfaces. An interface is essentially a specification that is used to facilitate communication between software components, possibly written by different vendors. An interface says, ‘‘if your cod e follows this set of rules then my software component will be able to communicate with it.’’ In the next section we will see how interfaces make writing device drivers a much simpler task.C++ and Device DriversIn a flexible automation platform, one optimal use for interfaces is in device drivers. We would like our open-architecture software to provide a generic way for end users to write their own device drivers without having to divulge the secrets of our source code to them. To do this, we define a simplifiedC++ interface for a generic device, as shown here:class IDevice{public:virtual string GetName() ? 0; //Returns the name//of the devicevirtual void Initialize() ? 0; //Called to//initialize the devicevirtual void Run() ? 0; // Called to run the device};In the example above, a Ctt class (or object) called IDevice has been defined. The prefix I in IDevice stands for ‘‘interface’’. This class defines three public virtual methods: GetName, Initialize, and Run. The virtual keyword is what enables polymorphism, allowing the executing program to run the methods of the inheriting class. When a virtual method declaration is suffixed with ?0, there is no base class implementation. Such a method is referred to as ‘‘pure virtual’’. A class like IDevice that contains only pure virtual functions is known as an ‘‘abstract class’’, or an‘‘interface’’. The IDevice definition, along with appropriate documentation, can be published to the user community,allowing developers to generate their own device drivers that implement the IDevice interface.Suppose a thermal plate sealer manufacturer wants to write a driver that can be controlled by our software package. They would use inheritance to implement our IDevice interface and then override the methods to produce the desired behavior: class CSealer : public IDevice{public:virtual string GetName() {return ‘‘Sealer’’;}virtual void Initialize() {InitializeSealer();}virtual void Run() {RunSealCycle();}private:void InitializeSealer();void RunSealCycle();};Here the user has created a new class called CSealer that inherits from the IDevice interface. The public methods,those that are accessible from outside of the class, are the interface methods defined in IDevice. One, GetName, simply returns the name of the device type that this driver controls.The other methods,Initialize() and Run(), call private methods that actually perform the work. Notice how the privatekeyword is used to prevent external objects from calling InitializeSealer() and RunSealCycle() directly.When the controlling software executes, polymorphism will be used at runtime to call the GetName, Initialize, and Run methods in the CSealer object, allowing the device defined therein to be controlled.DoSomeWork(){//Get a reference to the device driver we want to useIDevice&device ? GetDeviceDriver();//Tell the world what we’re about to do.cout !! ‘‘Initializing ’’!! device.GetName();//Initialize the devicedevice.Initialize();//Tell the world what we’re about to do.cout !! ‘‘Running a cycle on ’’ !!device.GetName();//Away we go!device.Run();}The code snippet above shows how the IDevice interface can be used to generically control a device. If GetDevice-Driver returns a reference to a CSealer object, then DoSomeWork will control sealers. If GetDeviceDriver returns a reference to a pipettor, then DoSomeWork will control pipettors. Although this is a simplified example, it is straightforward to imagine how the use of interfaces and polymorphism can lead to great economies of scale in controller software development.Additional interfaces can be generated along the same lines as IDevice. For example, an interface perhaps called ILMS could be used to facilitate communication to and from a LIMS.The astute reader will notice that the claim that anythird party can develop drivers simply by implementing the IDevice interface is slightly flawed. The problem is that any driver that the user writes, like CSealer, would have to be linked directly to the controlling software’s exec utable to be used. This problem is solved by a number of existing technologies, including Microsoft’s COMor .NET, or by CORBA. All of these technologies allow end users to implement abstract interfaces in standalone components that can be linked at runtime rather than at design time. The details are beyond the scope of this article.中文翻译：随着研究实验室更加自动化，实验室管理人员出现的新问题。

计算机java外文翻译外文文献英文文献

英文原文:Title: Business Applications of Java. Author: Erbschloe, Michael, Business Applications of Java -- Research Starters Business, 2008DataBase: Research Starters - BusinessBusiness Applications of JavaThis article examines the growing use of Java technology in business applications. The history of Java is briefly reviewed along with the impact of open standards on the growth of the World Wide Web. Key components and concepts of the Java programming language are explained including the Java Virtual Machine. Examples of how Java is being used bye-commerce leaders is provided along with an explanation of how Java is used to develop data warehousing, data mining, and industrial automation applications. The concept of metadata modeling and the use of Extendable Markup Language (XML) are also explained.Keywords Application Programming Interfaces (API's); Enterprise JavaBeans (EJB); Extendable Markup Language (XML); HyperText Markup Language (HTML); HyperText Transfer Protocol (HTTP); Java Authentication and Authorization Service (JAAS); Java Cryptography Architecture (JCA); Java Cryptography Extension (JCE); Java Programming Language; Java Virtual Machine (JVM); Java2 Platform, Enterprise Edition (J2EE); Metadata Business Information Systems > Business Applications of JavaOverviewOpen standards have driven the e-business revolution. Networking protocol standards, such as Transmission Control Protocol/Internet Protocol (TCP/IP), HyperText Transfer Protocol (HTTP), and the HyperText Markup Language (HTML) Web standards have enabled universal communication via the Internet and the World Wide Web. As e-business continues to develop, various computing technologies help to drive its evolution.The Java programming language and platform have emerged as major technologies for performing e-business functions. Java programming standards have enabled portability of applications and the reuse of application components across computing platforms. Sun Microsystems' Java Community Process continues to be a strong base for the growth of the Java infrastructure and language standards. This growth of open standards creates new opportunities for designers and developers of applications and services (Smith, 2001).Creation of Java TechnologyJava technology was created as a computer programming tool in a small, secret effort called "the Green Project" at Sun Microsystems in 1991. The Green Team, fully staffed at 13 people and led by James Gosling, locked themselves away in an anonymous office on Sand Hill Road in Menlo Park, cut off from all regular communications with Sun, and worked around the clock for18 months. Their initial conclusion was that at least one significant trend would be the convergence of digitally controlled consumer devices and computers. A device-independent programming language code-named "Oak" was the result.To demonstrate how this new language could power the future of digital devices, the Green Team developed an interactive, handheld home-entertainment device controller targeted at the digital cable television industry. But the idea was too far ahead of its time, and the digital cable television industry wasn't ready for the leap forward that Java technology offered them. As it turns out, the Internet was ready for Java technology, and just in time for its initial public introduction in 1995, the team was able to announce that the Netscape Navigator Internet browser would incorporate Java technology ("Learn about Java," 2007).Applications of JavaJava uses many familiar programming concepts and constructs and allows portability by providing a common interface through an external Java Virtual Machine (JVM). A virtual machine is a self-contained operating environment, created by a software layer that behaves as if it were a separate computer. Benefits of creating virtual machines include better exploitation of powerful computing resources and isolation of applications to prevent cross-corruption and improve security (Matlis, 2006).The JVM allows computing devices with limited processors or memory to handle more advanced applications by calling up software instructions inside the JVM to perform most of the work. This also reduces the size and complexity of Java applications because many of the core functions and processing instructions were built into the JVM. As a result, software developersno longer need to re-create the same application for every operating system. Java also provides security by instructing the application to interact with the virtual machine, which served as a barrier between applications and the core system, effectively protecting systems from malicious code.Among other things, Java is tailor-made for the growing Internet because it makes it easy to develop new, dynamic applications that could make the most of the Internet's power and capabilities. Java is now an open standard, meaning that no single entity controls its development and the tools for writing programs in the language are available to everyone. The power of open standards like Java is the ability to break down barriers and speed up progress.Today, you can find Java technology in networks and devices that range from the Internet and scientific supercomputers to laptops and cell phones, from Wall Street market simulators to home game players and credit cards. There are over 3 million Java developers and now there are several versions of the code. Most large corporations have in-house Java developers. In addition, the majority of key software vendors use Java in their commercial applications (Lazaridis, 2003).ApplicationsJava on the World Wide WebJava has found a place on some of the most popular websites in the world and the uses of Java continues to grow. Java applications not only provide unique user interfaces, they also help to power the backend of websites. Two e-commerce giants that everybody is probably familiar with (eBay and Amazon) have been Java pioneers on the World Wide Web.eBayFounded in 1995, eBay enables e-commerce on a local, national and international basis with an array of Web sites-including the eBay marketplaces, PayPal, Skype, and -that bring together millions of buyers and sellers every day. You can find it on eBay, even if you didn't know it existed. On a typical day, more than 100 million items are listed on eBay in tens of thousands of categories. Recent listings have included a tunnel boring machine from the Chunnel project, a cup of water that once belonged to Elvis, and the Volkswagen that Pope Benedict XVI owned before he moved up to the Popemobile. More than one hundred million items are available at any given time, from the massive to the miniature, the magical to the mundane, on eBay; the world's largest online marketplace.eBay uses Java almost everywhere. To address some security issues, eBay chose Sun Microsystems' Java System Identity Manager as the platform for revamping its identity management system. The task at hand was to provide identity management for more than 12,000 eBay employees and contractors.Now more than a thousand eBay software developers work daily with Java applications. Java's inherent portability allows eBay to move to new hardware to take advantage of new technology, packaging, or pricing, without having to rewrite Java code ("eBay drives explosive growth," 2007).Amazon (a large seller of books, CDs, and other products) has created a Web Service application that enables users to browse their product catalog and place orders. uses a Java application that searches the Amazon catalog for books whose subject matches a user-selected topic. The application displays ten books that match the chosen topic, and shows the author name, book title, list price, Amazon discount price, and the cover icon. The user may optionally view one review per displayed title and make a buying decision (Stearns & Garishakurthi, 2003).Java in Data Warehousing & MiningAlthough many companies currently benefit from data warehousing to support corporate decision making, new business intelligence approaches continue to emerge that can be powered by Java technology. Applications such as data warehousing, data mining, Enterprise Information Portals (EIP's), and Knowledge Management Systems (which can all comprise a businessintelligence application) are able to provide insight into customer retention, purchasing patterns, and even future buying behavior.These applications can not only tell what has happened but why and what may happen given certain business conditions; allowing for "what if" scenarios to be explored. As a result of this information growth, people at all levels inside the enterprise, as well as suppliers, customers, and others in the value chain, are clamoring for subsets of the vast stores of information such as billing, shipping, and inventory information, to help them make business decisions. While collecting and storing vast amounts of data is one thing, utilizing and deploying that data throughout the organization is another.The technical challenges inherent in integrating disparate data formats, platforms, and applications are significant. However, emerging standards such as the Application Programming Interfaces (API's) that comprise the Java platform, as well as Extendable Markup Language (XML) technologies can facilitate the interchange of data and the development of next generation data warehousing and business intelligence applications. While Java technology has been used extensively for client side access and to presentation layer challenges, it is rapidly emerging as a significant tool for developing scaleable server side programs. The Java2 Platform, Enterprise Edition (J2EE) provides the object, transaction, and security support for building such systems.Metadata IssuesOne of the key issues that business intelligence developers must solve is that of incompatible metadata formats. Metadata can be defined as information about data or simply "data about data." In practice, metadata is what most tools, databases, applications, and other information processes use to define, relate, and manipulate data objects within their own environments. It defines the structure and meaning of data objects managed by an application so that the application knows how to process requests or jobs involving those data objects. Developers can use this schema to create views for users. Also, users can browse the schema to better understand the structure and function of the database tables before launching a query.To address the metadata issue, a group of companies (including Unisys, Oracle, IBM, SAS Institute, Hyperion, Inline Software and Sun) have joined to develop the Java Metadata Interface (JMI) API. The JMI API permits the access and manipulation of metadata in Java with standard metadata services. JMI is based on the Meta Object Facility (MOF) specification from the Object Management Group (OMG). The MOF provides a model and a set of interfaces for the creation, storage, access, and interchange of metadata and metamodels (higher-level abstractions of metadata). Metamodel and metadata interchange is done via XML and uses the XML Metadata Interchange (XMI) specification, also from the OMG. JMI leverages Java technology to create an end-to-end data warehousing and business intelligence solutions framework.Enterprise JavaBeansA key tool provided by J2EE is Enterprise JavaBeans (EJB), an architecture for the development of component-based distributed business applications. Applications written using the EJB architecture are scalable, transactional, secure, and multi-user aware. These applications may be written once and then deployed on any server platform that supports J2EE. The EJB architecture makes it easy for developers to write components, since they do not need to understand or deal with complex, system-level details such as thread management, resource pooling, and transaction and security management. This allows for role-based development where component assemblers, platform providers and application assemblers can focus on their area of responsibility further simplifying application development.EJB's in the Travel IndustryA case study from the travel industry helps to illustrate how such applications could function. A travel company amasses a great deal of information about its operations in various applications distributed throughout multiple departments. Flight, hotel, and automobile reservation information is located in a database being accessed by travel agents worldwide. Another application contains information that must be updated with credit and billing historyfrom a financial services company. Data is periodically extracted from the travel reservation system databases to spreadsheets for use in future sales and marketing analysis.Utilizing J2EE, the company could consolidate application development within an EJB container, which can run on a variety of hardware and software platforms allowing existing databases and applications to coexist with newly developed ones. EJBs can be developed to model various data sets important to the travel reservation business including information about customer, hotel, car rental agency, and other attributes.Data Storage & AccessData stored in existing applications can be accessed with specialized connectors. Integration and interoperability of these data sources is further enabled by the metadata repository that contains metamodels of the data contained in the sources, which then can be accessed and interchanged uniformly via the JMI API. These metamodels capture the essential structure and semantics of business components, allowing them to be accessed and queried via the JMI API or to be interchanged via XML. Through all of these processes, the J2EE infrastructure ensures the security and integrity of the data through transaction management and propagation and the underlying security architecture.To consolidate historical information for analysis of sales and marketing trends, a data warehouse is often the best solution. In this example, data can be extracted from the operational systems with a variety of Extract, Transform and Load tools (ETL). The metamodels allow EJBsdesigned for filtering, transformation, and consolidation of data to operate uniformly on datafrom diverse data sources as the bean is able to query the metamodel to identify and extract the pertinent fields. Queries and reports can be run against the data warehouse that contains information from numerous sources in a consistent, enterprise-wide fashion through the use of the JMI API (Mosher & Oh, 2007).Java in Industrial SettingsMany people know Java only as a tool on the World Wide Web that enables sites to perform some of their fancier functions such as interactivity and animation. However, the actual uses for Java are much more widespread. Since Java is an object-oriented language like C++, the time needed for application development is minimal. Java also encourages good software engineering practices with clear separation of interfaces and implementations as well as easy exception handling.In addition, Java's automatic memory management and lack of pointers remove some leading causes of programming errors. Most importantly, application developers do not need to create different versions of the software for different platforms. The advantages available through Java have even found their way into hardware. The emerging new Java devices are streamlined systems that exploit network servers for much of their processing power, storage, content, and administration.Benefits of JavaThe benefits of Java translate across many industries, and some are specific to the control and automation environment. For example, many plant-floor applications use relatively simple equipment; upgrading to PCs would be expensive and undesirable. Java's ability to run on any platform enables the organization to make use of the existing equipment while enhancing the application.IntegrationWith few exceptions, applications running on the factory floor were never intended to exchange information with systems in the executive office, but managers have recently discovered the need for that type of information. Before Java, that often meant bringing together data from systems written on different platforms in different languages at different times. Integration was usually done on a piecemeal basis, resulting in a system that, once it worked, was unique to the two applications it was tying together. Additional integration required developing a brand new system from scratch, raising the cost of integration.Java makes system integration relatively easy. Foxboro Controls Inc., for example, used Java to make its dynamic-performance-monitor software package Internet-ready. This software provides senior executives with strategic information about a plant's operation. The dynamic performance monitor takes data from instruments throughout the plant and performs variousmathematical and statistical calculations on them, resulting in information (usually financial) that a manager can more readily absorb and use.ScalabilityAnother benefit of Java in the industrial environment is its scalability. In a plant, embedded applications such as automated data collection and machine diagnostics provide critical data regarding production-line readiness or operation efficiency. These data form a critical ingredient for applications that examine the health of a production line or run. Users of these devices can take advantage of the benefits of Java without changing or upgrading hardware. For example, operations and maintenance personnel could carry a handheld, wireless, embedded-Java device anywhere in the plant to monitor production status or problems.Even when internal compatibility is not an issue, companies often face difficulties when suppliers with whom they share information have incompatible systems. This becomes more of a problem as supply-chain management takes on a more critical role which requires manufacturers to interact more with offshore suppliers and clients. The greatest efficiency comes when all systems can communicate with each other and share information seamlessly. Since Java is so ubiquitous, it often solves these problems (Paula, 1997).Dynamic Web Page DevelopmentJava has been used by both large and small organizations for a wide variety of applications beyond consumer oriented websites. Sandia, a multiprogram laboratory of the U.S. Department of Energy's National Nuclear Security Administration, has developed a unique Java application. The lab was tasked with developing an enterprise-wide inventory tracking and equipment maintenance system that provides dynamic Web pages. The developers selected Java Studio Enterprise 7 for the project because of its Application Framework technology and Web Graphical User Interface (GUI) components, which allow the system to be indexed by an expandable catalog. The flexibility, scalability, and portability of Java helped to reduce development timeand costs (Garcia, 2004)IssueJava Security for E-Business ApplicationsTo support the expansion of their computing boundaries, businesses have deployed Web application servers (WAS). A WAS differs from a traditional Web server because it provides a more flexible foundation for dynamic transactions and objects, partly through the exploitation of Java technology. Traditional Web servers remain constrained to servicing standard HTTP requests, returning the contents of static HTML pages and images or the output from executed Common Gateway Interface (CGI ) scripts.An administrator can configure a WAS with policies based on security specifications for Java servlets and manage authentication and authorization with Java Authentication andAuthorization Service (JAAS) modules. An authentication and authorization service can bewritten in Java code or interface to an existing authentication or authorization infrastructure. Fora cryptography-based security infrastructure, the security server may exploit the Java Cryptography Architecture (JCA) and Java Cryptography Extension (JCE). To present the user with a usable interaction with the WAS environment, the Web server can readily employ a formof "single sign-on" to avoid redundant authentication requests. A single sign-on preserves user authentication across multiple HTTP requests so that the user is not prompted many times for authentication data (i.e., user ID and password).Based on the security policies, JAAS can be employed to handle the authentication process with the identity of the Java client. After successful authentication, the WAS securitycollaborator consults with the security server. The WAS environment authentication requirements can be fairly complex. In a given deployment environment, all applications or solutions may not originate from the same vendor. In addition, these applications may be running on different operating systems. Although Java is often the language of choice for portability between platforms, it needs to marry its security features with those of the containing environment.Authentication & AuthorizationAuthentication and authorization are key elements in any secure information handling system. Since the inception of Java technology, much of the authentication and authorization issues have been with respect to downloadable code running in Web browsers. In many ways, this had been the correct set of issues to address, since the client's system needs to be protected from mobile code obtained from arbitrary sites on the Internet. As Java technology moved from a client-centric Web technology to a server-side scripting and integration technology, it required additional authentication and authorization technologies.The kind of proof required for authentication may depend on the security requirements of a particular computing resource or specific enterprise security policies. To provide such flexibility, the JAAS authentication framework is based on the concept of configurable authenticators. This architecture allows system administrators to configure, or plug in, the appropriate authenticatorsto meet the security requirements of the deployed application. The JAAS architecture also allows applications to remain independent from underlying authentication mechanisms. So, as new authenticators become available or as current authentication services are updated, system administrators can easily replace authenticators without having to modify or recompile existing applications.At the end of a successful authentication, a request is associated with a user in the WAS user registry. After a successful authentication, the WAS consults security policies to determine if the user has the required permissions to complete the requested action on the servlet. This policy canbe enforced using the WAS configuration (declarative security) or by the servlet itself (programmatic security), or a combination of both.The WAS environment pulls together many different technologies to service the enterprise. Because of the heterogeneous nature of the client and server entities, Java technology is a good choice for both administrators and developers. However, to service the diverse security needs of these entities and their tasks, many Java security technologies must be used, not only at a primary level between client and server entities, but also at a secondary level, from served objects. By using a synergistic mix of the various Java security technologies, administrators and developers can make not only their Web application servers secure, but their WAS environments secure as well (Koved, 2001).ConclusionOpen standards have driven the e-business revolution. As e-business continues to develop, various computing technologies help to drive its evolution. The Java programming language and platform have emerged as major technologies for performing e-business functions. Java programming standards have enabled portability of applications and the reuse of application components. Java uses many familiar concepts and constructs and allows portability by providing a common interface through an external Java Virtual Machine (JVM). Today, you can find Java technology in networks and devices that range from the Internet and scientific supercomputers to laptops and cell phones, from Wall Street market simulators to home game players and credit cards.Java has found a place on some of the most popular websites in the world. Java applications not only provide unique user interfaces, they also help to power the backend of websites. While Java technology has been used extensively for client side access and in the presentation layer, it is also emerging as a significant tool for developing scaleable server side programs.Since Java is an object-oriented language like C++, the time needed for application development is minimal. Java also encourages good software engineering practices with clear separation of interfaces and implementations as well as easy exception handling. Java's automatic memory management and lack of pointers remove some leading causes of programming errors. The advantages available through Java have also found their way into hardware. The emerging new Java devices are streamlined systems that exploit network servers for much of their processing power, storage, content, and administration.中文翻译:标题：Java的商业应用。

专业计算机英文作文带翻译

专业计算机英文作文带翻译英文，As a professional in the field of computer science, I have always been passionate about technology and its applications in various industries. My journey in this field started during my undergraduate studies, where I was exposed to the fundamentals of programming, algorithms, and data structures. The more I delved into the subject, the more I realized the immense potential and impact of computer science on our daily lives.One of the most exciting aspects of my profession is the constant innovation and evolution of technology. For example, the development of artificial intelligence and machine learning has revolutionized the way we approach problem-solving and decision-making. These technologies have been applied in diverse fields, from healthcare to finance, and have significantly improved efficiency and accuracy.In addition to the technical skills, my profession alsorequires strong problem-solving abilities and critical thinking. I often find myself tackling complex issues and devising creative solutions to overcome them. This aspect of my work keeps me engaged and motivated, as I enjoy the challenge of unraveling intricate problems.Moreover, communication and collaboration are essential in my profession. I frequently work in multidisciplinary teams, where I have to effectively communicate technical concepts to non-technical stakeholders. This requires me to be articulate and adaptable in my communication style, ensuring that everyone is on the same page.Overall, being a professional in computer science is not just about writing code or developing software. It encompasses a wide range of skills and qualities, from technical expertise to problem-solving and communication. I am proud to be a part of this dynamic and fast-paced industry, and I look forward to contributing to its continuous growth and innovation.中文，作为计算机科学领域的专业人士，我一直对技术及其在各个行业中的应用充满热情。

英文文献及翻译(计算机专业)

NET-BASED TASK MANAGEMENT SYSTEM Hector Garcia-Molina, Jeffrey D. Ullman, Jennifer WisdomABSTRACTIn net-based collaborative design environment, design resources become more and more varied and complex. Besides common information management systems, design resources can be organized in connection with design activities.A set of activities and resources linked by logic relations can form a task. A task has at least one objective and can be broken down into smaller ones. So a design project can be separated into many subtasks forming a hierarchical structure.Task Management System (TMS) is designed to break down these tasks and assign certain resources to its task nodes．As a result of decomposition.al1 design resources and activities could be managed via this system.KEY WORDS：Collaborative Design, Task Management System (TMS), Task Decomposition, Information Management System1 IntroductionAlong with the rapid upgrade of request for advanced design methods, more and more design tool appeared to support new design methods and forms. Design in a web environment with multi-partners being involved requires a more powerful and efficient management system .Design partners can be located everywhere over the net with their own organizations. They could be mutually independent experts or teams of tens ofemployees. This article discusses a task management system (TMS) which manages design activities and resources by breaking down design objectives and re-organizing design resources in connection with the activities. Comparing with common information management systems (IMS) like product data management system and document management system, TMS can manage the whole design process. It has two tiers which make it much more f1exible in structure.The 1ower tier consists of traditional common IMSS and the upper one fulfills logic activity management through controlling a tree-like structure, allocating design resources and making decisions about how to carry out a design project. Its functioning paradigm varies in different projects depending on the project’s scale and purpose. As a result of this structure, TMS can separate its data model from its logic mode1.It could bring about structure optimization and efficiency improvement, especially in a large scale project.2 Task Management in Net-Based Collaborative Design Environment 2.1 Evolution of the Design EnvironmentDuring a net-based collaborative design process, designers transform their working environment from a single PC desktop to LAN, and even extend to WAN. Each design partner can be a single expert or a combination of many teams of several subjects, even if they are far away from each other geographically. In the net-based collaborative design environment, people from every terminal of the net can exchange their information interactively with each other and send data to authorized roles via their design tools. The Co Design Space is such an environment which provides a set of these tools to help design partners communicate and obtaindesign information. Code sign Space aims at improving the efficiency of collaborative work, making enterprises increase its sensitivity to markets and optimize the configuration of resource.2.2 Management of Resources and Activities in Net-Based Collaborative EnvironmentThe expansion of design environment also caused a new problem of how to organize the resources and design activities in that environment. As the number of design partners increases, resources also increase in direct proportion. But relations between resources increase in square ratio. To organize these resources and their relations needs an integrated management system which can recognize them and provide to designers in case of they are needed.One solution is to use special information management system (IMS).An IMS can provide database, file systems and in/out interfaces to manage a given resource. For example there are several IMS tools in Co Design Space such as Product Data Management System, Document Management System and so on. These systems can provide its special information which design users want.But the structure of design activities is much more complicated than these IM S could manage, because even a simple design project may involve different design resources such as documents, drafts and equipments. Not only product data or documents, design activities also need the support of organizations in design processes. This article puts forward a new design system which attempts to integrate different resources into the related design activities. That is task management system (TMS).3 Task Breakdown Model3.1 Basis of Task BreakdownWhen people set out to accomplish a project, they usually separate it into a sequence of tasks and finish them one by one. Each design project can be regarded as an aggregate of activities, roles and data. Here we define a task as a set of activities and resources and also having at least one objective. Because large tasks can be separated into small ones, if we separate a project target into several lower—level objectives, we define that the project is broken down into subtasks and each objective maps to a subtask. Obviously if each subtask is accomplished, the project is surely finished. So TMS integrates design activities and resources through planning these tasks.Net-based collaborative design mostly aims at products development. Project managers (PM) assign subtasks to designers or design teams who may locate in other cities. The designers and teams execute their own tasks under the constraints which are defined by the PM and negotiated with each other via the collaborative design environment. So the designers and teams are independent collaborative partners and have incompact coupling relationships. They are driven together only by theft design tasks. After the PM have finished decomposing the project, each designer or team leader who has been assigned with a subtask become a 1ow-class PM of his own task. And he can do the same thing as his PM done to him, re-breaking down and re-assigning tasks.So we put forward two rules for Task Breakdown in a net-based environment, incompact coupling and object-driven. Incompact coupling means the less relationship between two tasks. When two subtasks were coupled too tightly, therequirement for communication between their designers will increase a lot. Too much communication wil1 not only waste time and reduce efficiency, but also bring errors. It will become much more difficult to manage project process than usually in this situation. On the other hand every task has its own objective. From the view point of PM of a superior task each subtask could be a black box and how to execute these subtasks is unknown. The PM concerns only the results and constraints of these subtasks, and may never concern what will happen inside it.3.2 Task Breakdown MethodAccording to the above basis, a project can be separated into several subtasks. And when this separating continues, it will finally be decomposed into a task tree. Except the root of the tree is a project, all eaves and branches are subtasks. Since a design project can be separated into a task tree, all its resources can be added to it depending on their relationship. For example, a Small-Sized-Satellite.Design (3SD) project can be broken down into two design objectives as Satellite Hardware. Design (SHD) and Satellite-Software-Exploit (SSE). And it also has two teams. Design team A and design team B which we regard as design resources. When A is assigned to SSE and B to SHD. We break down the project as shown in Fig 1.It is alike to manage other resources in a project in this way. So when we define a collaborative design project’s task model, we should first claim the project’s targets. These targets include functional goals, performance goals, and quality goals and so on. Then we could confirm how to execute this project. Next we can go on to break down it. The project can be separated into two or more subtasks since there are at 1east two partners in a collaborative project. Either wecould separate the project into stepwise tasks, which have time sequence relationships in case of some more complex projects and then break down the stepwise tasks according to their phase-to-phase goals.There is also another trouble in executing a task breakdown. When a task is broken into severa1 subtasks; it is not merely “a simple sum motion”of other tasks. In most cases their subtasks could have more complex relations.To solve this problem we use constraints. There are time sequence constraint (TSC) and logic constraint (LC). The time sequence constraint defines the time relationships among subtasks. The TSC has four different types, FF, FS, SF and SS. F means finish and S presents start. If we say Tabb is FS and lag four days, it means Tb should start no later than four days after Ta is finished.The logic constraint is much more complicated. It defines logic relationship among multiple tasks.Here is given an example:“Task TA is separated into three subtasks, Ta, T b and Tc. But there are two more rules.Tb and Tc can not be executed until Ta is finished.Tb and Tc can not be executed both，that means if Tb was executed, Tc should not be executed, and vice versa. This depends on the result of Ta.”So we say Tb and Tc have a logic constraint. After finishing breaking down the tasks, we can get a task tree as Fig, 2 illustrates.4 TMS Realization4.1 TMS StructureAccording to our discussion about task tree model and task breakdown basis, we can develop a Task Management System (TMS)based on Co Design Space using Java language, JSP technology and Microsoft SQL 2000. The task management system’s structure is shown in Fig. 3.TMS has four main modules namely Task Breakdown, Role Management, Statistics and Query and Data Integration. The Task Breakdown module helps users to work out task tree. Role Management module performs authentication and authorization of access control. Statistics and Query module is an extra tool for users to find more information about their task. The last Data Integration Module provides in/out interface for TMS with its peripheral environment.4.2 Key Points in System Realization4.2.1 Integration with Co Design SpaceCo Design Space is an integrated information management system which stores, shares and processes design data and provides a series of tools to support users. These tools can share all information in the database because they have a universal Data Mode1. Which is defined in an XML (extensible Markup Language) file, and has a hierarchical structure. Based on this XML structure the TMS h data mode1 definition is organized as following.<?xml version= 1.0 encoding= UTF-8’?><!ELEMENT ProductProcessResource (Prcses?, History?，AsBuiltProduct*，ItemsObj?, Changes?, ManufacturerParts?，SupplierParts?，AttachmentsObj? ， Contacts?， PartLibrary?，AdditionalAttributes*)><!ELEMENT Prcses (Prcs+) ><!ELEMENT Prcs (Prcses，PrcsNotes?，PrcsArc*，Contacts?，AdditionalAttributes*，Attachments?)><!ELEM ENT PrcsArc EMPTY><!ELEMENT PrcsNotes(PrcsNote*)><!ELEMENT PrcsNote EMPTY>Notes: Element “Pros” is a task node object, and “Process” is a task set object which contains subtask objects and is belongs to a higher class task object. One task object can have no more than one “Presses” objects. According to this definition, “Prcs”objects are organized in a tree-formation process. The other objects are resources, such as task link object (“Presage”), task notes (“Pros Notes”), and task documents (“Attachments”) .These resources are shared in Co Design database.文章出处：计算机智能研究[J],47卷，2007：647-703基于网络的任务管理系统摘要在网络与设计协同化的环境下，设计资源变得越来越多样化和复杂化。

计算机专业外文文献翻译--Linux—网络时代的操作系统

英文参考文献及翻译Linux - Operating system of cybertimesThough for a lot of people , regard Linux as the main operating system to make up huge work station group, finish special effects of " Titanic " make , already can be regarded as and show talent fully. But for Linux, this only numerous news one of. Recently, the manufacturers concerned have announced that support the news of Linux to increase day by day, users' enthusiasm to Linux runs high unprecedentedly too. Then, Linux only have operating system not free more than on earth on 7 year this piece what glamour, get the favors of such numerous important software and hardware manufacturers as the masses of users and Orac le , Informix , HP , Sybase , Corel , Intel , Netscape , Dell ,etc. , OK?1.The background of Linux and characteristicLinux is a kind of " free (Free ) software ": What is called free,mean users can obtain the procedure and source code freely , and can use them freely , including revise or copy etc.. It is a result of cybertimes, numerous technical staff finish its research and development together through Inte rnet, countless user is it test and except fault , can add user expansion function that oneself make conveniently to participate in. As the most outstanding one in free software, Linux has characteristic of the following:(1)Totally follow POSLX standard, expand the network operatingsystem of supporting all AT&T and BSD Unix characteristic. Because of inheritting Unix outstanding design philosophy , and there are clean , stalwart , high-efficient and steady kernels, their all key codes are finished by Li nus Torvalds and other outstanding programmers, without any Unix code of AT&T or Berkeley, so Linu x is not Unix, but Linux and Unix are totally compatible.(2)Real many tasks, multi-user's system, the built-in networksupports, can be with such seamless links as NetWare , Windows NT , OS/2 , Unix ,etc.. Network in various kinds of Unix it tests to be fastest in comparing and assess efficiency. Support such many kinds of files systems as FAT16 , FAT32 , NTFS , Ex t2FS , ISO9600 ,etc. at the same time .(3) Can operate it in many kinds of hardwares platform , including such processors as Alpha , SunSparc , PowerPC , MIPS ,etc., to various kinds of new-type peripheral hardwares, can from distribute on global numerous programmer there getting support rapidly too.(4) To that the hardware requires lower, can obtain very good performance on more low-grade machine , what deserves particular mention is Linux outstanding stability , permitted " year " count often its running times.2.Main application of Linux At present,Now, the application of Linux mainly includes:(1) Internet/Intranet: This is one that Linux was used most at present, it can offer and include Web server , all such Inter net services as Ftp server , Gopher server , SMTP/POP3 mail server , Proxy/Cache server , DNS server ,etc.. Linux kernel supports IPalias , PPP and IPtunneling, these functions can be used for setting up fictitious host computer , fictitious service , VPN (fictitious special-purpose network ) ,etc.. Operating Apache Web server on Linux mainly, the occupation rate of market in 1998 is 49%, far exceeds the sum of such several big companies as Microsoft , Netscape ,etc..(2) Because Linux has outstanding networking ability , it can be usedin calculating distributedly large-scaly, for instance cartoon making , scientific caculation , database and file server ,etc..(3) As realization that is can under low platform fullness of Unix that operate , apply at all levels teaching and research work of universities and colleges extensively, if Mexico government announce middle and primary schools in the whole country dispose Linux and offer Internet service for student already.(4) Tabletop and handling official business appliedly. Application number of people of in this respect at present not so good as Windows of Microsoft far also, reason its lie in Lin ux quantity , desk-top of application software not so good as Windows application far not merely,because the characteristic of the freedom software makes it not almost have advertisement that support (though the function of Star Office is not second to MS Office at the same time, but there are actually few people knowing).3.Can Linux become a kind of major operating system?In the face of the pressure of coming from users that is strengthened day by day, more and more commercial companies transplant its application to Linux platform, comparatively important incident was as follows, in 1998 ①Compaq and HP determine to put forward user of requirement truss up Linux at their servers , IBM and Dell promise to offer customized Linux system to user too. ②Lotus announce, Notes the next edition include one special-purpose edition in Linux. ③Corel Company transplants its famous WordPerfect to on Linux, and free issue. Corel also plans to move the other figure pattern process products to Linux platform completely.④Main database producer: Sybase , Informix , Oracle , CA , IBM have already been transplanted one's own database products to on Linux, or has finished Beta edition, among them Oracle and Informix also offer technical support to their products.4.The gratifying one is, some farsighted domestic corporations have begun to try hard to change this kind of current situation already. Stone Co. not long ago is it invest a huge sum of money to claim , regard Linux as platform develop a Internet/Intranet solution, regard this as the core and launch Stone's system integration business , plan to set up nationwide Linux technical support organization at the same time , take the lead to promote the freedom software application and development in China. In addition domestic computer Company , person who win of China , devoted to Linux relevant software and hardware application of system popularize too. Is it to intensification that Linux know , will have more and more enterprises accede to the ranks that Linux will be used with domestic every enterprise to believe, more software will be planted in Linux platform. Meanwhile, the domestic university should regard Linux as the original version and upgrade already existing Unix content of courses , start with analysing the source code and revising the kernel and train a large number of senior Linux talents, improve our country's own operating system. Having only really grasped the operating system, the software industry of our country could be got rid of and aped sedulously at present, the passive state led by the nose byothers, create conditions for revitalizing the software industry of our country fundamentally.中文翻译Linux—网络时代的操作系统虽然对许多人来说，以Linux作为主要的操作系统组成庞大的工作站群，完成了《泰坦尼克号》的特技制作，已经算是出尽了风头。

【计算机专业文献翻译】21世纪的高级编程语言

外文文献阅读与翻译第1章英文原文Scripting: Higher Level Programming for the 21st Century1 IntroductionFor the last fifteen years a fundamental change has been occurring in the way people write computer programs. The change is a transition from system programming languages such as C or C++ to scripting languages such as Perl or Tcl. Although many people are participating in the change, few people realize that it is occurring and even fewer people know why it is happening. This article is an opinion piece that explains why scripting languages will handle many of the programming tasks of the next century better than system programming languages.Scripting languages are designed for different tasks than system programming languages, and this leads to fundamental differences in the languages. System programming languages were designed for building data structures and algorithms from scratch, starting from the most primitive computer elements such as words of memory. In contrast, scripting languages are designed for gluing: they assume the existence of a set of powerful components and are intended primarily for connecting components together. System programming languages are strongly typed to help manage complexity, while scripting languages are typeless to simplify connections between components and provide rapid application development.Scripting languages and system programming languages are complementary, and most major computing platforms since the 1960's have provided both kinds of languages. The languages are typically used together in component frameworks, where components are created with system programming languagesand glued together with scripting languages. However, several recent trends, such as faster machines, better scripting languages, the increasing importance of graphical user interfaces and component architectures, and the growth of the Internet, have greatly increased the applicability of scripting languages. These trends will continue over the next decade, with more and more new applications written entirely in scripting languages and system programming languages used primarily for creating components.1.1 2 Scripting languagesScripting languages such as Perl[9], Python[4], Rexx[6], Tcl[8], Visual Basic, and the Unix shells represent a very different style of programming than system programming languages. Scripting languages assume that there already exists a collection of useful components written in other languages. Scripting languages aren't intended for writing applications from scratch; they are intended primarily for plugging together components. For example, Tcl and Visual Basic can be used to arrange collections of user interface controls on the screen, and Unix shell scripts are used to assemble filter programs into pipelines. Scripting languages are often used to extend the features of components but they are rarely used for complex algorithms and data structures; features like these are usually provided by the components. Scripting languages are sometimes referred to as glue languages or system integration languages.In order to simplify the task of connecting components, scripting languages tend to be typeless: all things look and behave the same so that they are interchangeable. For example, in Tcl or Visual Basic a variable can hold a string one moment and an integer the next. Code and data are often interchangeable, so that a program can write another program and then execute it on the fly. Scripting languages are often string-oriented, since this provides a uniform representation for many different things.A typeless language makes it much easier to hook together components. There are no a priori restrictions on how things can be used, and all components and values are represented in a uniform fashion. Thus any component or value can be used in any situation; components designed for one purpose can be used for totally different purposes never foreseen by the designer. For example, in the Unix shells, all filter programs read a stream of bytes from an input and write a string of bytes to an output; any two programs can be connected together by attaching the output of one program to the input of the other. The following shell command stacks three filters together to count the number of lines in the selection that contain the word "scripting":select | grep scripting | wcThe select program reads the text that is currently selected on the display and prints it on its output; the grep program reads its input and prints on its output the lines containing "scripting"; the wc program counts the number of lines on its input. Each of these programs can be used in numerous other situations to perform different tasks.The strongly typed nature of system programming languages discourages reuse. Typing encourages programmers to create a variety of incompatible interfaces ("interfaces are good; more interfaces are better"). Each interface requires objects of specific types and the compiler prevents any other types of objects from being used with the interface, even if that would be useful. In order to use a new object with an existing interface, conversion code must be written to translate between the type of the object and the type expected by the interface. This in turn requires recompiling part or all of the application, which isn't possible in the common case where the application is distributed in binary form.To see the advantages of a typeless language, consider the following Tcl command:button .b -text Hello! -font {Times 16} -command {puts hello}This command creates a new button control that displays a text string in a 16-point Times font and prints a short message when the user clicks on the control. It mixes six different types of things in a single statement: a command name (button), a button control (.b), property names (-text, -font, and -command), simple strings (Hello! and hello), a font name (Times 16) that includes a typeface name (Times) and a size in points (16), and a Tcl script (puts hello). Tcl represents all of these things uniformly with strings. In this example the properties may be specified in any order and unspecified properties are given default values; more than 20 properties were left unspecified in the example.The same example requires 7 lines of code in two methods when implemented in Java. With C++ and Microsoft Foundation Classes, it requires about 25 lines of code in three procedures (see [7]for the code for these examples). Just setting the font requires several lines of code in Microsoft Foundation Classes:CFont *fontPtr = new CFont();fontPtr->CreateFont(16, 0, 0,0,700, 0, 0, 0, ANSI_CHARSET,OUT_DEFAULT_PRECIS,CLIP_DEFAULT_PRECIS, DEFAULT_QUALITY,DEFAULT_PITCH|FF_DONTCARE, "Times New Roman");buttonPtr->SetFont(fontPtr);Much of this code is a consequence of the strong typing. In order to set the font of a button, its SetFont method must be invoked, but this method must be passed a pointer to a CFont object. This in turn requires a new object to be declared and initialized. In order to initialize the CFont object its CreateFont method must be invoked, but CreateFont has a rigid interface that requires 14 different arguments to be specified. In Tcl, the essential characteristics of the font (typeface Times, size 16 points) can be used immediately with no declarations or conversions. Furthermore, Tcl allows the behavior for the button to be included directly in the command that creates the button, while C++ and Java require it to be placed in a separately declared method.(In practice, a trivial example like this would probably be handled with a graphical development environment that hides the complexity of the underlying language: the user enters property values in a form and the development environment outputs the code. However, in more complex situations such as conditional assignment of property values or interfaces generated programmatically, the developer must write code in the underlying language.)It might seem that the typeless nature of scripting languages could allow errors to go undetected, but in practice scripting languages are just as safe as system programming languages. For example, an error will occur if the font size specified for the button example above is a non-integer string such as xyz. The difference is that scripting languages do their error checking at the last possible moment, when a value is used. Strong typing allows errors to be detected at compile-time, so the cost of run-time checks is avoided. However, the price to be paid for this efficiency is restrictions on how information can be used: this results in more code and less flexible programs.Another key difference between scripting languages and system programming languages is th at scripting languages are usually interpreted whereas system programming languages are usually compiled. Interpreted languages provide rapid turnaround during development by eliminating compile times. Interpreters also make applications more flexible by allowing users to program the applications at run-time. For example, many synthesis and analysis tools for integrated circuits include a Tcl interpreter; users of the programs write Tcl scripts to specify their designs and control the operation of the tools. Interpreters also allow powerful effects to be achieved by generating code on the fly. For example, a Tcl-based Web browser can parse a Web page by translating the HTML for the page into a Tcl script using a few regular expression substitutions. It then executes the Tcl script to render the page on the screen.Scripting languages are less efficient than system programming languages, in part because they use interpreters instead of compilers but also because their basic components are chosen for power and ease of use rather than an efficient mapping onto the underlying hardware. For example, scripting languages often use variable-length strings in situations where a system programming language would use a binary value that fits in a single machine word, and scripting languages often use hash tables where system programming languages use indexed arrays.Fortunately, the performance of a scripting language isn't usually a major issue. Applications for scripting languages are generally smaller than applications for system programming languages, and the performance of a scripting application tends to be dominated by the performance of thecomponents, which are typically implemented in a system programming language.Scripting languages are higher level than system programming languages, in the sense that a single statement does more work on average. A typical statement in a scripting language executes hundreds or thousands of machine instructions, whereas a typical statement in a system programming language executes about five machine instructions (see Figure 1). Part of this difference is because scripting languages use interpreters, which are less efficient than the compiled code for system programming languages. But much of the difference is because the primitive operations in scripting languages have greater functionality. For example, in Perl it is about as easy to invoke a regular expression substitution as it is to invoke an integer addition. In Tcl, a variable can have traces associated with it so that setting the variable causes side effects; for example, a trace might be used to keep the variable's value updated continuously on the screen. Because of the features described above, scripting languages allow very rapid development for applications that are gluing-oriented.To summarize, scripting languages are designed for gluing applications. They provide a higher level of programming than assembly or system programming languages, much weaker typing than system programming languages, and an interpreted development environment. Scripting languages sacrifice execution speed to improve development speed.中文翻译脚本语言：21世纪的高级编程语言1.简介在过去的十五年里，人们编写计算机程序的方法发生了根本的转变。

【计算机专业文献翻译】远程教育

届毕业设计（论文）英文参考文献英文文献1：Management Information Systems: Do they give manufacturing organizations what they want?文献出处，年，Vol.卷(期) Journal of Materials Processing Technology,1996,61作者： Daniel Wybrow, Pate Cameron-MacDonald英文文献2：Database research faces the information explosion文献出处，年，Vol.卷(期) Communications of the ACM,1997,40作者： Henry F.Korth, Abraham.Silberschatz学生院系专业名称学生班级学生学号学生姓名学生层次本科发展中国家的远程教育：有人计算过成本—效益吗？Stephen Ruth and Min Shi, George Mason University, Virginia, USA远程教育已成为教育和区域发展战略与规划的一个主要问题.对于学院的管理者来说这是一个完全可能的用来部署给学生新的资源来源。

对于企业来说它不但改变了传统的教育方法并且是盈利的新来源。

对于跨国组织如联合国开发规划署（UNDP）或者世界银行，远程教育有可能提供宝贵的知识资源给一些地球上最贫穷国家,同时拉动新生通用基础设施的增长。

本文采取简单冷静的观点看待发展中的远程教育。

远程教育是信息通讯科技(ICT)讨论的一个重要的课题。

因为这是一个不但是个媒介也是一项事业。

作为一个媒介它承诺提供知识给世界上最穷的国家，作为一项事业它对许多ICT意味着一项崇高的事业,就像AlfredBork 说的"一个新的学习典范."对于那些认为对世界上最贫穷的国家来说教育是最重要的目的的人来说，也许远程教育是完成一个奇迹,改革飞跃最重要的方法。

计算机科学与技术外文翻译英文文献中英对照

附件1：外文资料翻译译文大容量存储器由于计算机主存储器的易失性和容量的限制, 大多数的计算机都有附加的称为大容量存储系统的存储设备, 包括有磁盘、CD 和磁带。

相对于主存储器，大的容量储存系统的优点是易失性小，容量大，低成本, 并且在许多情况下, 为了归档的需要可以把储存介质从计算机上移开。

术语联机和脱机通常分别用于描述连接于和没有连接于计算机的设备。

联机意味着，设备或信息已经与计算机连接，计算机不需要人的干预，脱机意味着设备或信息与机器相连前需要人的干预，或许需要将这个设备接通电源，或许包含有该信息的介质需要插到某机械装置里。

大量储存器系统的主要缺点是他们典型地需要机械的运动因此需要较多的时间，因为主存储器的所有工作都由电子器件实现。

1. 磁盘今天，我们使用得最多的一种大量存储器是磁盘，在那里有薄的可以旋转的盘片，盘片上有磁介质以储存数据。

盘片的上面和（或）下面安装有读/写磁头，当盘片旋转时，每个磁头都遍历一圈，它被叫作磁道，围绕着磁盘的上下两个表面。

通过重新定位的读/写磁头，不同的同心圆磁道可以被访问。

通常，一个磁盘存储系统由若干个安装在同一根轴上的盘片组成，盘片之间有足够的距离，使得磁头可以在盘片之间滑动。

在一个磁盘中，所有的磁头是一起移动的。

因此，当磁头移动到新的位置时，新的一组磁道可以存取了。

每一组磁道称为一个柱面。

因为一个磁道能包含的信息可能比我们一次操作所需要得多，所以每个磁道划分成若干个弧区，称为扇区，记录在每个扇区上的信息是连续的二进制位串。

传统的磁盘上每个磁道分为同样数目的扇区，而每个扇区也包含同样数目的二进制位。

（所以，盘片中心的储存的二进制位的密度要比靠近盘片边缘的大）。

因此，一个磁盘存储器系统有许多个别的磁区, 每个扇区都可以作为独立的二进制位串存取，盘片表面上的磁道数目和每个磁道上的扇区数目对于不同的磁盘系统可能都不相同。

磁区大小一般是不超过几个KB; 512 个字节或1024 个字节。

计算机自动化外文翻译外文文献英文文献原文

The Application of Visualization Technology in ElectricPower Automation SystemWang Chuanqi, Zou QuanxiElectric Power Automation System Department of Yantai Dongfang Electronics Information IndustryCo., Ltd.Abstract: Isoline chart is widely used chart. The authors have improved the existing isoline formation method, proposed a simple and practical isoline formation method, studied how to fill the isoline chart, brought about a feasible method of filling the isoline chart and discussed the application of isoline chart in electric power automation system.Key words: Visualization; Isoline; Electric power automation systemIn the electric power system industry, the dispatching of electric network becomes increasingly important along with the expansion of electric power system and the increasing demands of people towards electric power. At present, electric network dispatching automation system is relatively advanced and relieves the boring and heavy work for operation staff. However, there is a large amount or even oceans of information. Especially when there is any fault, a large amount of alarm information and fault information will flood in the dispatching center. Faced with massive data, operation staff shall rely on some simple and effective tool to quickly locate the interested part in order to grasp the operation state of the system as soon as possible and to predict, identify and remove fault.Meanwhile, the operation of electric power system needs engineers and analysts in the system to analyze a lot of data. The main challenge that a system with thousands of buses poses for electric power automation system is that it needs to supply a lot of data to users in a proper way and make users master and estimate the state of the system instinctively and quickly. This is the case especially in electric network analyzing software. For example, the displaying way of data is more important in analyzing the relations between the actual trend, planned trend of electric network and the transmission capacity of the system. The application of new computer technology and visualization technology in the electric power automation system can greatly satisfy new development and new demands of electric power automation system.The word “Visualization” originates from English “Visual” and itsoriginal meaning is visual and vivid. In fact, the transformation of any abstract things and processes into graphs and images can be regarded as visualization. But as a subject term, the word “Visualization” officially appeared in a seminar held by National Science Foundation (shortened as NSF) of the USA in February 1987. The official report published after the seminar defined visualization, its covered fields and its recent and long-term research direction, which symbolized that “Visualization” became mature as a subject at the international level.The basic implication of visualization is to apply the principles and methods of computer graphics and general graphics to transforming large amounts of data produced by scientific and engineering computation into graphs and images and displaying them in a visual way. It refers to multi research fields such as computer graphics, image processing, computer vision, computer-aided design (CAD) and graphical user interface (GUI), etc. and has become an important direction for the current research of computer graphics.There are a lot of methods to realize visualization and each method has its unique features and applies to different occasions. Isoline and isosurface is an important method in visualization and can be applied to many occasions. The realization of isoline (isosurface) and its application in the electric power automation system will be explained below in detail.1、 Isoline (Isosurface)Isoline is defined with all such points (x i, y i), in which F(x i, y i)=F i (F i is a set value), and these points connected in certain order form the isoline of F(x,y) whose value is F i…Common isolines such as contour line and isotherm, etc.are based on the measurement of certain height and temperature.Regular isoline drawing usually adopts grid method and the steps are as follows:gridingdiscrete data;converting grid points into numerical value;calculating isoline points; tracing isoline; smoothing and marking isoline; displaying isoline or filling the isoline chart. Recently, some people have brought about the method of introducing triangle grid to solve the problems of quadrilateral grid. What the two methods have in common is to use grid and isoline points on the grid for traveling tracing, which results in the following defects in the drawing process:(1) The two methods use the grid structure, first find out isoline pointson each side of certain quadrilateral grid or triangle grid, and then continue to find out isoline points from all the grids, during which a lot of judgment are involved, increasing the difficulty of program realization. When grid nodes become isoline points, they shall be treated as singular nodes, which not only reduces the graph accuracy but also increases the complexity of drawing.(2) The two methods produce drawn graphs with inadequate accuracy and intersection may appear during traveling tracing. The above methods deal with off-grid points using certain curve-fitting method. That is, the methods make two approximations and produce larger tolerance.(3) The methods are not universal and they can only deal with data of grid structure. If certain data is transformed into the grid structure, interpolation is needed in the process, which will definitely reduce the accuracy of graphs.To solve the problems, we adopt the method of raster graph in drawing isoline when realizing the system function, and it is referred to as non-grid method here. This method needs no grid structures and has the following advantages compared to regular methods:(1) Simple programming and easily realized, with no singular nodes involved and no traveling tracing of isoline. All these advantages greatly reduce the complexity of program design.(2)Higher accuracy. It needs one approximation while regular methods need two or more.(3) More universal and with no limits of grid1.1 Isoline Formation Method of Raster GraphThe drawing of raster graph has the following features: the area of drawing isoline is limited and is composed of non-continuous points. In fact, raster graph is limited by computer screen and what people can see is just a chart formed by thousands of or over ten thousand discrete picture elements. For example, a straight line has limited length on computers and is displayed with lots of discrete points. Due to the limitations of human eyes, it seemscontinuous. Based on the above features, this paper proposes isoline formation method of raster graph. The basic idea of this method is: as computer graphs are composed of discrete points, one just needs to find out all the picture element points on the same isoline, which will definitely form thisisoline.Take the isoline of rectangular mountain area for example to discuss detailed calculation method. Data required in calculation is the coordinates and altitude of each measuring point, i.e., (x i ,y i ,z i ), among which z i represents the altitude of No.i measuring point and there are M measuring points in total. Meanwhile, the height of isoline which is to be drawn is provided. For example, starting from h 0 , an isoline is drawn with every height difference of ∆h0 and total m isolines are drawn. Besides, the size of the screen area to be displayed is known and here (StartX,StartY) represents the top left corner of this area while (EndX ，EndY)represents the low right corner of this area. The calculation method for drawing its isoline is as follows:(1) Find out the value of x i and y i of the top left corner and low right corner points in the drawing area, which are represented by X max ，X min ，Y max ,Y min ;(2)Transform the coordinate (x i ,y i ) into screen coordinate (SX i ,SY i ) and the required transformation formula is as follows:sx i =x i -X min /X max -X min (EndX-StartX)sy i =y i -Y min /Y max -Y min (EndY-StartY)Fig. 1 Height computation sketch(3) i ＝startX,j=StartY; Suppose i ＝startX,j=StartY;(4) Use the method of calculating height (such as distance weighting method and least square method, etc.) to calculate out the height h 1, h 2, h 3 of points (i,j), (i+1,j) and (i,j+1), i.e., the height of the three points P 1, P 2 and P 3 in Fig. 1;(5) Check the value of h 1, h 2, h 3 and determine whether there is any isoline crossing according to the following methods:①k=1,h=h 0；①k=1,h=h 0；②Judge whether (P 1-h)*(P 2-h)≤0 is justified. If justified, continue the next step; otherwise, perform ⑤;③Judge whether ｜P1-h｜=｜P2-h｜ is justified. If justified, it indicates that there is an isoline crossing P1, P2, dot the two points and jumpto (6); otherwise, continue next step;④Judge whether ｜P1-h｜＜｜P2-h｜is justified. If justified, it indicates that there is an isoline crossing P1, dot this point; otherwise, dot P2;⑤Judge whether (P1-h)*(P3-h)≤0 is justified. If justified, continue next step; otherwise, perform ⑧.⑥Judge whether｜P1-h｜＝｜P3-h｜is justified. If justified, dot the twopoints P1\,P3 and jump to (6);otherwise, jump to ⑤;⑦Judge whether｜P1-h｜＜｜P3-h｜is justified. If justified, dot P1; otherwise, dot P3;⑧Suppose k:=k+1 and judge whether k＜m+1 I is justified. If unjustified, continue next step; otherwise, suppose h:=h+∆h0 and return to ②.(6) Suppose j:j+1 and judge whether j<EndY is justified. If unjustified,continue next step; otherwise, return to (4);(7) Suppose i:=i+1 and judge whether i<EndX is justified. If unjustified,continue next step; otherwise, return to (4);(8) The end.In specific program design, in order to avoid repeated calculation, an array can be used to keep all the value of P2 in Column i+1 and another variable is used to keep the value of P3.From the above calculation method, it can be seen th at this method doesn’tinvolve the traveling of isoline, the judgment of grid singular nodes and theconnection of isoline, etc., which greatly simplifies the programming and iseasily realized, producing no intersection lines in the drawn chart.1.2 Griding and Determining NodesTime consumption of a calculation method is of great concern. Whencalculating the height of (i,j), all the contributing points to the height ofthis point need to be found out. If one searches through the whole array, it is very time consuming. Therefore, the following regularized grid method is introduced to accelerate the speed.First, two concepts, i.e., influence domain and influence point set, are provided and defined as follows: Definition 1: influence domain O(P) of node P refers to the largest area in which this nodes has some influence on other nodes. In this paper, it can refer to the closed disc with radius as r (predetermined) or the square with side length as a (predetermined).Definition 2: influence point set S(P)of node P refers to the collection of all the nodes which can influence node P. In this paper, it refers to the point set with the number of elements as n (predetermined), i.e., the number of all the known contributing nodes to the height of node (i,j) can only be n and these nodes are generally n nodes closet to node P.According to the above definition, in order to calculate out the height of any node (i,j), one just needs to find out all the nodes influencing the height of this node and then uses the interpolation method according totwo-dimensional surface fitting. Here, we will explain in detail how to calculate out the height of node (i,j) with Definition 1, i.e., the method of influence domain, and make similar calculation with Definition 2.Grid structure is used to determine other nodes in the influence domainof node (i,j). Irregular area is covered with regular grid, in which the grids have the same size and the side of grid is parallel with X axis and Y axis. The grid is described as follows:(x min,x max,NCX)(y min,y max,NCY)In the formula, x min, y max and x max, y max are respectively the minimum and maximum coordinates of x, y direction of the area; NCX is the number of grids in X direction; NCY is the number of grids in Y direction.Determining which grid a node belongs to is performed in the following two steps. Suppose the coordinate of this node is (x,y). First, respectively calculate its grid No. in x direction and y direction, and the formula is as follows:IX＝NCX*（x-x min)/(xmax-x min)+1；IY＝NCY（y-y min)/(y max-y min)+1。

计算机专业毕业设计论文外文文献中英文翻译——java对象

1 . Introduction To Objects1.1The progress of abstractionAll programming languages provide abstractions. It can be argued that the complexity of the problems you’re able to solve is directly related to the kind and quality of abstraction。

By “kind” I mean，“What is it that you are abstracting?” Assembly language is a small abstraction of the underlying machine. Many so—called “imperative” languages that followed （such as FORTRAN，BASIC, and C) were abstractions of assembly language。

These languages are big improvements over assembly language，but their primary abstraction still requires you to think in terms of the structure of the computer rather than the structure of the problem you are trying to solve。

The programmer must establish the association between the machine model (in the “solution space，” which is the place where you’re modeling that problem, such as a computer) and the model of the problem that is actually being solved (in the “problem space,” which is the place where the problem exists). The effort required to perform this mapping, and the fact that it is extrinsic to the programming language，produces programs that are difficult to write and expensive to maintain，and as a side effect created the entire “programming methods” industry.The alter native to modeling the machine is to model the problem you’re trying to solve。

计算机专业中英文文献翻译

1In the past decade the business environment has changed dramatically. The world has become a small and very dynamic marketplace. Organizations today confront new markets, new competition and increasing customer expectations. This has put a tremendous demand on manufacturers to; 1) Lower total costs in the complete supply chain 2) Shorten throughput times 3) Reduce stock to a minimum 4) Enlarge product assortment 5) Improve product quality 6) Provide more reliable delivery dates and higher service to the customer 7) Efficiently coordinate global demand, supply and production. Thus today's organization have to constantly re-engineer their business practices and procedures to be more and more responsive to customers and competition. In the 1990's information technology and business process re-engineering, used in conjunction with each other, have emerged as important tools which give organizations the leading edge.ERP Systems EvolutionThe focus of manufacturing systems in the 1960's was on inventory control. Most of the software packages then (usually customized) were designed to handle inventory based on traditional inventory concepts. In the 1970's the focus shifted to MRP (Material Requirement Planning) systems which translatedthe Master Schedule built for the end items into time-phased net requirements for the sub-assemblies, components and raw materials planning and procurement,In the 1980's the concept of MRP-II (Manufacturing Resources Planning) evolved which was an extension of MRP to shop floor and distribution management activities. In the early 1990's, MRP-II was further extended to cover areas like Engineering, Finance, Human Resources, Projects Management etc i.e. the complete gamut of activities within any business enterprise. Hence, the term ERP (Enterprise Resource Planning) was coined.In addition to system requirements, ERP addresses technology aspects like client/server distributedarchitecture, RDBMS, object oriented programming etc. ERP Systems-Bandwidth ERP solutions address broad areas within any business like Manufacturing, Distribution, Finance, Project Management, Service and Maintenance, Transportation etc. A seamless integration is essential to provide visibility and consistency across the enterprise.An ERP system should be sufficiently versatile to support different manufacturing environments like make-to-stock, assemble-to-order and engineer-to-order. The customer order decoupling point (CODP) should be flexible enough to allow the co-existence of these manufacturing environments within the same system. It is also very likely that the same product may migrate from one manufacturing environment to another during its produce life cycle.The system should be complete enough to support both Discrete as well as Process manufacturing scenario's. The efficiency of an enterprise depends on the quick flow of information across the complete supply chain i.e. from the customer to manufacturers to supplier. This places demands on the ERP system to have rich functionality across all areas like sales, accounts receivable, engineering, planning, inventory management, production, purchase, accounts payable, quality management, distribution planning and external transportation. EDI (Electronic Data Interchange) is an important tool in speeding up communications with trading partners.More and more companies are becoming global and focusing on down-sizing and decentralizing their business. ABB and Northern Telecom are examples of companies which have business spread around the globe. For these companies to manage their business efficiently, ERP systems need to have extensive multi-site management capabilities. The complete financial accounting and management accounting requirementsof the organization should be addressed. It is necessary to have centralized or de-centralized accounting functions with complete flexibility to consolidate corporate information.After-sales service should be streamlined and managed efficiently. A strong EIS (Enterprise Information System) with extensive drill down capabilities should be available for the top management to get a birds eye view of the health of their organization and help them to analyze performance in key areas.Evaluation CriteriaSome important points to be kept in mind while evaluating an ERP software include: 1) Functional fit with the Company's business processes 2) Degree of integration between the various components of the ERP system 3) Flexibility and scalability 4) Complexity; user friendliness 5) Quick implementation; shortened ROI period 6) Ability to support multi-site planning and control 7) Technology; client/server capabilities, database independence, security 8)Availability of regular upgrades 9) Amount of customization required 10) Local support infrastructure II) Availability of reference sites 12) Total costs,including cost of license, training, implementation, maintenance, customization and hardware requirements.ERP Systems-ImplementationThe success of an ERP solution depends on how quick the benefits can be reaped from it. This necessitates rapid implementations which lead to shortened ROI periods. Traditional approach to implementation has been to carry out a Business Process Re-engineering exercise and define a "TO BE"model before the ERP system implementation. This led to mismatches between the proposed model and the ERP functionality, the consequence of which was customizations, extended implementation time frames, higher costs and loss of user confidence.ERP Systems-The FutureThe Internet represents the next major technology enabler which allows rapid supply chain management between multiple operations and trading partners. Most ERP systems are enhancing their products to become "Internet Enabled" so that customers worldwide can have direct to the supplier's ERP system. ERP systems are building in the Workflow Management functionally which provides a mechanism to manage and controlthe flow of work by monitoring logistic aspects like workload, capacity, throughout times, work queue lengths and processing times.译文1在过去十年中，商业环境发生了巨大的变化。

计算机英文文献加翻译

Management Information System OverviewManagement Information System is that we often say that the MIS, is a human, computers and other information can be composed of the collection, transmission, storage, maintenance and use of the system, emphasizing the management, stressed that the modern information society In the increasingly popular. MIS is a new subject, it across a number of areas, such as scientific management and system science, operations research, statistics and computer science. In these subjects on the basis of formation of information-gathering and processing methods, thereby forming a vertical and horizontal weaving, and systems.The 20th century, along with the vigorous development of the global economy, many economists have proposed a new management theory. In the 1950s, Simon made dependent on information management and decision-making ideas. Wiener published the same period of the control theory, that he is a management control process. 1958, Gail wrote: "The management will lower the cost of timely and accurate information to better control." During this period, accounting for the beginning of the computer, data processing in the term.1970, Walter T. Kenova just to the management information system under a definition of the term: "verbal or written form, at the right time to managers, staff and outside staff for the past, present, the projection of future Enterprise and its environment-related information 原文请找腾讯3249114六,维^论~文.网 no application model, no mention of computer applications.1985, management information systems, the founder of the University of Minnesota professor of management at the Gordon B. Davis to a management information system a more complete definition of "management information system is a computer hardware and software resources, manual operations, analysis, planning , Control and decision-making model and the database - System. It provides information to support enterprises or organizations of the operation, management and decision-making function. "Comprehensive definition of thisExplained that the goal of management information system, functions and composition, but also reflects the management information system at the time of level.With the continuous improvement of science and technology, computer science increasingly mature, the computer has to be our study and work on the run along. Today, computers are already very low price, performance, but great progress, and it was used in many areas, the computer was so popular mainly because of the following aspects: First, the computer can substitute for many of the complex Labor. Second, the computer can greatly enhance people's work efficiency. Third, the computer can save a lot of resources. Fourth, the computer can make sensitive documents more secure.Computer application and popularization of economic and social life in various fields. So that the original old management methods are not suited now more and social development. Many people still remain in the previous manual. This greatly hindered the economic development of mankind. In recent years, with the University of sponsoring scale is growing, the number of students in the school also have increased, resulting in educational administration is the growing complexity of the heavy work, to spend a lot of manpower, material resources, and the existing management of student achievement levels are not high, People have been usin g the traditional method of document management student achievement, the management there are many shortcomings, such as: low efficiency, confidentiality of the poor, and Shijianyichang, will have a large number of documents and data, which is useful for finding, updating andmaintaining Have brought a lot of difficulties. Such a mechanism has been unable to meet the development of the times, schools have become more and more day-to-day management of a bottleneck. In the information age this traditional management methods will inevitably be computer-based information management replaced.As part of the computer application, the use of computers to students student performance information for management, with a manual management of the incomparable advantages for example: rapid retrieval, to find convenient, high reliability and large capacity storage, the confidentiality of good, long life, cost Low. These advantages can greatly improve student performance management students the efficiency of enterprises is also a scientific, standardized management, and an important condition for connecting the world. Therefore, the development of such a set of management software as it is very necessary thing.Design ideas are all for the sake of users, the interface nice, clear and simple operation as far as possible, but also as a practical operating system a good fault-tolerant, the user can misuse a timely manner as possible are given a warning, so that users timely correction . T o take full advantage of the functions of visual FoxPro, design powerful software at the same time, as much as possible to reduce the occupiers system resources.Visual FoxPro the command structure and working methods:Visual FoxPro was originally called FoxBASE, the U.S. Fox Software has introduced a database products, in the run on DOS, compatible with the abase family. Fox Software Microsoft acquisition, to be developed so that it can run on Windows, and changed its name to Visual FoxPro. Visual FoxPro is a powerful relational database rapid application development tool, the use of Visual FoxPro can create a desktop database applications, client / server applications and Web services component-based procedures, while also can use ActiveX controls or API function, and so on Ways to expand the functions of Visual FoxPro.1651First, work methods1. Interactive mode of operation(1) order operationVF in the order window, through an order from the keyboard input of all kinds of ways to complete the operation order.(2) menu operationVF use menus, windows, dialog to achieve the graphical interface features an interactive operation. (3) aid operationVF in the system provides a wide range of user-friendly operation of tools, such as the wizard, design, production, etc..2. Procedure means of implementationVF in the implementation of the procedures is to form a group of orders and programming language, an extension to save. PRG procedures in the document, and then run through the automatic implementation of this order documents and award results are displayed.Second, the structure of command1. Command structure2. VF orders are usually composed of two parts: The first part is the verb order, also known as keywords, for the operation of the designated order functions; second part of the order clause, for an order that the operation targets, operating conditions and other information . VF order form are as follows:3. <Order verb> "<order clause>"4. Order in the format agreed symbols5. VF in the order form and function of the use of the symbol of the unity agreement, the meaning of these symbols are as follows:6. Than that option, angle brackets within the parameters must be based on their format input parameters.7. That may be options, put in brackets the parameters under specific requ ests from users choose to enter its parameters.8. Third, the project manager9. Create a method10. command window: CREA T PROJECT <file name>11. Project Manager12. tab13. All - can display and project management applications of all types of docume nts, "All" tab contains five of its right of the tab in its entirety.14. Data - management application projects in various types of data files, databases, free form, view, query documents.15. Documentation - display 原文请找腾讯3249114六,维^论~文.网 , statements, documents, labels and other documents.16. Category - the tab display and project management applications used in the class library documents, including VF's class library system and the user's own design of the library.17. Code - used in the project management procedures code documents, such as: program files (. PRG), API library and the use of project management for generation of applications (. APP).18. (2) the work area19. The project management work area is displayed and management of all types of document window.20. (3) order button21. Project Manager button to the right of the order of the work area of the document window to provide command.22. 4, project management for the use of23. 1. Order button function24. New - in the work area window selected certain documents, with new orders button on the new document added to the project management window.25. Add - can be used VF "file" menu under the "new" order and the "T ools" menu under the "Wizard" order to create the various independent paper added to the project manager, unified organization with management.26. Laws - may amend the project has been in existence in the various documents, is still to use such documents to modify the design interface.27. Sports - in the work area window to highlight a specific document, will run the paper.28. Mobile - to check the documents removed from the project.29. Even the series - put the item in the relevant documents and even into the application executable file.Database System Design :Database design is the logical database design, according to a forthcoming data classification system and the logic of division-level organizations, is user-oriented. Database design needsof various departments of the integrated enterprise archive data and data needs analysis of the relationship between the various data, in accordance with the DBMS.管理信息系统概要管理信息系统就是我们常说的MIS（Management Information System），是一个由人、计算机等组成的能进行信息的收集、传送、储存、维护和使用的系统，在强调管理，强调信息的现代社会中它越来越得到普及。

英文文献及翻译(计算机专业)

英文文献及翻译(计算机专业)The increasing complexity of design resources in a net-based collaborative XXX common systems。

design resources can be organized in n with design activities。

A task is formed by a set of activities and resources linked by logical ns。

XXX managementof all design resources and activities via a Task Management System (TMS)。

which is designed to break down tasks and assign resources to task nodes。

This XXX。

2 Task Management System (TMS)TMS is a system designed to manage the tasks and resources involved in a design project。

It poses tasks into smaller subtasks。

XXX management of all design resources and activities。

TMS assigns resources to task nodes。

XXX。

3 Collaborative DesignCollaborative design is a process that XXX a common goal。

In a net-based collaborative design environment。

n XXX n for all design resources and activities。

【计算机专业文献翻译】网络性能的测量

英文翻译：本文出自《Computer Network》第四版Andrew S.Tanenbaum著Network Performance MeasurementWhen a network performs poorly, its users often complain to the folks running it, demanding improvements. To improve the performance, the operators must first determine exactly what is going on. To find out what is really happening, the operators must make measurements. In this section we will look at network performance measurements. The discussion below is based on the work of Mogul (1993).The basic loop used to improve network performance contains the following steps:1.Measure the relevant network parameters and performance.2.Try to understand what is going on.3.Change one parameter.These steps are repeated until the performance is good enough or it is clear that the last drop of improvement has been squeezed out.Measurements can be made in many ways and at many locations (both physically and in the protocol stack). The most basic kind of measurement is to start a timer when beginning some activity and see how long that activity takes. For example, knowing how long it takes for a TPDU to be acknowledged is a key measurement. Other measurements are made with counters that record how often some event has happened (e.g., number of lost TPDUS). Finally, one is often interested in knowing the amount of something, such as the number of bytes processed in a certain time interval.Measuring network performance and parameters has many potential pitfalls. Below we list a few of them. Any systematic attempt to measure network performance should be careful to avoid these.Make Sure That the Sample Size Is Large EnoughDo not measure the time to send one TPDU, but repeat the measurement, say, one million times and take the average. Having a large sample will reduce the uncertainty in the measured mean and standard deviation. This uncertainty can be computed using standard statistical formulas.Make Sure That the Samples Are RepresentativeIdeally, the whole sequence of one million measurements should be repeated at different times of the day and the week to see the effect of different system loads on the measured quantity. Measurements of congestion, for example, are of little use if they are made at a moment when there is no congestion. Sometimes the results may be counterintuitive at first, such as heavy congestion at 10, 11, 1, and 2 o'clock, but no congestion at noon (when all the users are away at lunch).Be Careful When Using a Coarse-Grained ClockComputer clocks work by incrementing some counter at regular intervals. For example, a millisecond timer adds 1 to a counter every 1 msec. Using such a timer to measure an event that takes less than 1 msec is possible, but requires some care. (Some computers have more accurate clocks, of course.)To measure the time to send a TPDU, for example, the system clock (say, in milliseconds) should be read out when the transport layer code is entered and again when it is exited. If the true TPDU send time is 300 µsec, the difference between the two readings will be either 0 or 1, both wrong. However, if the measurement is repeated one million times and the total of all measurements added up and divided by one million, the mean time will be accurate to better than 1 µsec.Be Sure That Nothing Unexpected Is Going On during Your TestsMaking measurements on a university system the day some major lab project has to be turned in may give different results than if made the next day. Likewise, if some researcher has decided to run a video conference over your network during your tests, you may get a biased result. It is best to run tests on an idle system and create the entire workload yourself. Even this approach has pitfalls though. While you might think nobody will be using the network at 3 A.M., that might be precisely when the automatic backup program begins copying all the disks to tape. Furthermore, there might be heavy traffic for your wonderful World Wide Web pages from distant time zones.Caching Can Wreak Havoc with MeasurementsThe obvious way to measure file transfer times is to open a large file, read the whole thing, close it, and see how long it takes. Then repeat the measurement many more times to get a good average. The trouble is, the system may cache the file, so only the first measurement actually involves network traffic. The rest are just reads from thelocal cache. The results from such a measurement are essentially worthless (unless you want to measure cache performance).Often you can get around caching by simply overflowing the cache. For example, if the cache is 10 MB, the test loop could open, read, and close two 10-MB files on each pass, in an attempt to force the cache hit rate to 0. Still, caution is advised unless you are absolutely sure you understand the caching algorithm.Buffering can have a similar effect. One popular TCP/IP performance utility program has been known to report that UDP can achieve a performance substantially higher than the physical line allows. How does this occur? A call to UDP normally returns control as soon as the message has been accepted by the kernel and added to the transmission queue. If there is sufficient buffer space, timing 1000 UDP calls does not mean that all the data have been sent. Most of them may still be in the kernel, but the performance utility thinks they have all been transmitted.Understand What You Are MeasuringWhen you measure the time to read a remote file, your measurements depend on the network, the operating systems on both the client and server, the particular hardware interface boards used, their drivers, and other factors. If the measurements are done carefully, you will ultimately discover the file transfer time for the configuration you are using. If your goal is to tune this particular configuration, these measurements are fine.However, if you are making similar measurements on three different systems in order to choose which network interface board to buy, your results could be thrown off completely by the fact that one of the network drivers is truly awful and is only getting 10 percent of the performance of the board.网络性能的测量当一个网络的运行效果很差的时候，它的用户通常会向网络运行商抱怨并要求提高网络的质量。

英文文献及翻译：计算机程序

Computer Language and ProgrammingI. IntroductionProgramming languages, in computer sc ienc e, are the artific ial languages used to write a sequenc e of instructions (a computer program) that c an be run by a computer. Similar to natural languages, such as English, programming languages have a voc abulary, grammar, and syntax. How ever, natural languages are not suited for programming computers bec ause they are ambiguous, meaning that their vocabulary and grammatic al struc ture may be interpreted in multiple ways. The languages used to program computers must have simple logic al structures, and the rules for their grammar, spelling, and punctuation must be prec ise.Programming languages vary greatly in their sophistic ation and in their degree of versatility. Some programming languages are written to address a partic ular kind of computing problem or for use on a partic ular model of computer system. For instanc e, programming languages such as FORTRAN and COBOL w ere written to solve certain general types of programming problems—FORTRAN for sc ientific applic ations, and COBOL for business applic ations. Although these languages were designed to address spec ific categories of computer problems, they are highly portable, meaning that they may be used to program many types of computers. Other languages, such as mac hine languages, are designed to be used by one spec ific model of computer system, or even by one spec ific computer in c ertain researc h applications. The most c ommonly used programming languages are highly portable and can be used to effectively solve diverse types of computing problems. Languages like C, PASCAL and BASIC fall into this c ategory.II. Language TypesProgramming languages can be c lassified as either low-level languages or high-level languages. Low-level programming languages, or machine languages, are the most basic type of programming languages and can be understood directly by a c omputer. Machine languages differ depending on the manufacturer and model of computer. High-level languages are programming languages that must first be translated into a machine language before they c an be understood and processed by a computer. Examples of high-level languages are C, C++, PASCAL, and FORTRAN. Assembly languages are intermediate languages that are very c lose to mac hine languages and do not have the level of linguisticsophistic ation exhibited by other high-level languages, but must still be translated into mac hine language.1. Machine LanguagesIn mac hine languages, instructions are written as s equenc es of 1s and 0s, called bits, that a computer c an understand direc tly. An instruc tion in mac hine language generally tells the computer four things: (1) where to find one or two numbers or simple pieces of data in the main computer memory (Random Access Memory, or RAM), (2) a simple operation to perform, suc h as adding the two numbers together, (3) where in the main memory to put the result of this simple operation, and (4) where to find the next instruc tion to perform. While all exec utable programs ar e eventually read by the computer in mac hine language, they are not all programmed in machine language. It is extremely difficult to program directly in machine language bec ause the instructions are sequenc es of 1s and 0s. A typic al instruc tion in a mac hine language might read 10010 1100 1011 and mean add the contents of storage register A to the contents of storage register B.2. High-Level LanguagesHigh-level languages are relatively sophisticated sets of statements utilizing w ords and syntax from human language. They are more similar to normal human languages than assembly or machine languages and are therefore easier to use for writing c omplic ated programs. These programming languages allow larger and more complic ated programs to be developed faster. How ever, high-level languages must be translated into machine language by another program c alled a compiler before a c omputer can understand them. For this reason, programs written in a high-level language may take longer to execute and use up more memory than programs written in an assembly language.3. Assembly LanguagesComputer programmers use assembly languages to make mac hine-language programs easier to write. In an assembly language, each statement corresponds roughly to one mac hine language instruction. An assembly language statement is composed w ith the aid of easy to remember commands. The command to add the c ontents of the storage register A to the c ontents of storage register B might be written ADD B, A in a typical assembly language statement. Assembly languages share certain features w ith mac hine languages. For instance, it is possible to manipulate spec ific bits in both assembly and machinelanguages. Programmers use assemblylanguages when it is important to minimize the time it takes to run a program, because the translation from assembly language to machine language is relatively simple. Assembly languages are also used when some part of the c omputer has to be c ontrolled direc tly, such as individual dots on a monitor or the flow of individua l c harac ters to a printer.III. Classific ation of High-Level LanguagesHigh-level languages are c ommonly c lassified as proc edure-oriented, functional, objec t-oriented, or logic languages. The most common high-level languages today are proc edure-oriented languages. In these languages, one or more related blocks of statements that perform some complete function are grouped together into a program module, or proc edure, and given a name such as “proc edure A.” If the same sequence of operations is needed elsewhere in the program, a simple statement can be used to refer bac k to the proc edure. In essence, a proc edure is just amini- program. A large program c an be c onstructed by grouping together procedures that perform different tasks. Proc edural languages allo w programs to be shorter and easier for the c omputer to read, but they require the programmer to design eac h procedure to be general enough to be usedin different situations. Func tional languages treat proc edures like mathematic al functions and allow them to be processed like any other data in a program. This allows a much higher and more rigorous level of program construction. Func tional languages also allow variables—symbols for data that c an be spec ified and changed by the user as the program is running—to be given values only once. This simplifies programming by reduc ing the need to be concerned w ith the exac t order of statement execution, sinc e a variable does not have to be redec lared , or restated, eac h time it is used in a program statement. Many of the ideas from functional languages have become key parts of many modern procedural languages. Object-oriented languages are outgrowths of functional languages. In objec t-oriented languages, the c ode used to write the program and the data proc essed by the program are grouped together into units called objec ts. Objec ts are further grouped into c lasses, which define the attributes objects must have. A simple example of a c lass is the c lass Book. Objects w ithin this c lass might be Novel and Short Story. Objec ts also have certain functions assoc iated w ith them, called methods. Thecomputer accesses an objec t through the use of one of the object’s methods. The method performs some ac tion to the data in the object and returns this value to the computer. Classes of objec ts can also be further grouped into hierarchies, in whic h objects of one class can inherit methods from another c lass. The structure provided in object-oriented languages makes them very useful for complic ated programming tasks. Logic languages use logic as their mathematic al base. A logic program consists of sets of facts and if-then rules, whic h spec ify how one set of facts may be deduced from others, for example: If the statement X is true, then the statement Y is false. In the execution of such a program, an input statement can be logic ally deduced from other statements in the program. Many artific ial intelligenc e programs are written in suc h languages.IV. Language Structure and ComponentsProgramming languages use spec ific types of statements, or instructions, to provide func tional structure to the program. A statement in a program is a basic sentenc e that expresses a simple idea—its purpose is to give the computer a basic instruction. Statements define the types of data allow ed, how data ar e to be manipulated, and the w ays that proc edures and functions work. Programmers use statements to manipulate common components of programming languages, such as variables and macros (mini-programs within a program). Statements known as data dec larations give names and properties to elements of a program c alled variables. V ariables c an be assigned different values w ithin the program. The properties variables c an have are c alled types, and they inc lude such things as w hat possible values might be saved in the variables, how much numeric al accuracy is to be used in the values, and how one variable may represent a collection of simpler values in an organized fashion, such as a table or array. In many programming languages, a key data type is a pointer. V ariables that are pointers do not themselves have values; instead, they have information that the computer can use to loc ate some other variable—that is, they point to another variable. An expression is a piec e of a statement that describes a series of c omputati ons to be performed on some of the program’s variables, such as X+Y/Z, in which the variables are X, Y, and Z and the computations are addition and division. An assignment statement assigns a variable a value derived from some expression, while c onditional statements spec ify expressions to be tested and then used to selec t whic h other statements should be executed next.Proc edure and function statements define c ertain bloc ks of code as procedures or functions that can then be returned to later in the program. These statements also define the kinds of variables and parameters the programmer c an c hoose and the type of value that the c ode will return when an expression acc esses the procedure or function. Many programming languages also permit mini translation programs c alled macros. Macros translate segments of c ode that have been written in a language struc ture defined by the programmer into statements that the programming language understands.V. HistoryProgramming languages date back almost to the invent ion of the digital c omputer in the 1940s. The first assembly languages emerged in the late 1950s w ith the introduc tion of commerc ial c omputers. The first proc edural languages were developed in the late 1950s to early 1960s: FORTRAN, created by John Bac kus, and then COBOL, created by Grac e Hopper The first functional language w as LISP, written by John McCarthy4 in the late 1950s. Although heavily updated, all three languages are still w idely used today. In the late 1960s, the first objec t-oriented languages, such as SIMULA, emerged. Logic languages bec ame w ell known in the mid 1970swith the introduction of PROLOG6, a language used to program artific ial intelligenc e softw are. During the 1970s, proc edural languages c ontinued to develop w ith ALGOL, BASIC, PASCAL, C, and A d a SMALLTALK w as a highly influential object-oriented language that led to the merging ofobjec t- oriented and procedural languages in C++ and more rec ently in JAVA10. Although pure logic languages have dec lined in popularity, variations hav e bec ome vitally important in the form of relational languages for modern databases, such as SQL.计算机程序一、引言计算机程序是指导计算机执行某个功能或功能组合的一套指令。

计算机专业英文文献翻译

计算机英文文献翻译INDUSTTRY PERSPECTIVEUSING A DSS TO KEEP THE COST OF GAS DOWNThink you spend a lot on gas for you car every yer?J.B.Hunt Transportation Inc.spends a lot more..J.B.Hunt moves freight around the country on its 10,000trucks and 48,000 trailers.The company spent$250 million in 2004 on fuel.That figure was up by 40 percent over the previous year.Diesel fuel is the company''s second-largest expense(drivers''wages is the largest),and the freight hauler wanted to find a way to reduce that.part of the answer lay,as it often does,in IT.In2000,J.B.Hunt installed a decision support system that provides drivers with help in deciding which gas station to stop at for ing statellite communications,the system beams diesel-fuel prices from all over the country straight into the cabs of the tricks.The software accesses a database with local taxes for each area of the country and then calculates for the drivers how much refueling will actually cost.J.B.Hunt doesn''t require drivers to use this system,but provides incentives for those who do.The company estimates that the system saves about $1 million annually.Decision Support SystemIn Chapter 3,you saw how data mining can help you make business decisions by giving you the ability to slice and dice your way through massive amounts of information.Actually,a data warehouse with data-mining tools is a form of decision support.The term decision support system ,used broadly ,means any computerized system that helps you make decisions.Medicine can mean the whole health care industy or in can mean cough syrup,depending on the context.Narrowly definrd,a decision support system(DSS) si a highly flexible and interantive IT system that is designed to support decision making when the problem is not structured.A DSS is an alliance between you,the decision maker,and specialized support provided by IT(see figure4.4).IT brings speed,vast amounts information,and sophisticated processing capabilities to help you create information useful in making a decision.You bring know-how in the form of your experience,intuition,judgment,and knowledge of the relevant factors.IT provides great power ,but you-as the decision maker-must know what kinds of questions to ask of the information and how to process the information to get those questions answered.In fact,theprimary objective of a DSS is to improve your effectiveness as a decision maker by providing you with assistance that will complement your insights.This union of your know-how and IT power helps you generate business intelligence so that you can quickly respond to changes in the marketplace and manage resources in themost effective and efficient ways possible.Following are some example of the varid applicatins of DSSs:.。

计算机专业外文文献翻译

毕业设计（论文）外文文献翻译（本科学生用）题目：Plc based control system for the music fountain 学生姓名：_ ___学号：060108011117 学部（系）: 信息学部专业年级: _06自动化（1）班_指导教师： ___职称或学位：助教__20 年月日外文文献翻译（译成中文1000字左右）：【主要阅读文献不少于5篇，译文后附注文献信息，包括：作者、书名（或论文题目）、出版社（或刊物名称）、出版时间（或刊号）、页码。

提供所译外文资料附件（印刷类含封面、封底、目录、翻译部分的复印件等，网站类的请附网址及原文】英文节选原文：Central Processing Unit (CPU) is the brain of a PLC controller. CPU itself is usually one of the microcontrollers. Aforetime these were 8-bit microcontrollers such as 8051, and now these are 16-and 32-bit microcontrollers. Unspoken rule is that you’ll find mostly Hitachi and Fujicu microcontrollers in PLC controllers by Japanese makers, Siemens in European controllers, and Motorola microcontrollers in American ones. CPU also takes care of communication, interconnectedness among other parts of PLC controllers, program execution, memory operation, overseeing input and setting up of an output. PLC controllers have complex routines for memory checkup in order to ensure that PLC memory was not damaged (memory checkup is done for safety reasons).Generally speaking, CPU unit makes a great number of check-ups of the PLC controller itself so eventual errors would be discovered early. You can simply look at any PLC controller and see that there are several indicators in the form. of light diodes for error signalization.System memory (today mostly implemented in FLASH technology) is used by a PLC for a process control system. Aside form. this operating system it also contains a user program translated forma ladder diagram to a binary form. FLASH memory contents can be changed only in case where user program is being changed. PLC controllers were used earlier instead of PLASH memory and have had EPROM memory instead of FLASH memory which had to be erased with UV lamp and programmed on programmers. With the use of FLASH technology this process was greatly shortened. Reprogramming a program memory is done through a serial cable in a program for application development.User memory is divided into blocks having special functions. Some parts of a memory are used for storing input and output status. The real status of an input is stored either as “1”or as “0”in a specific memory bit/ each input or output has one corresponding bit in memory. Other parts of memory are used to store variable contents for variables used in used program. For example, time value, or counter value would be stored in this part of the memory.PLC controller can be reprogrammed through a computer (usual way), but also through manual programmers (consoles). This practically means that each PLC controller can programmed through a computer if you have the software needed for programming. Today’s transmission computers are ideal for reprogramming a PLC controller in factory itself. This is of great importance to industry. Once the system is corrected, it is also important to read the right program into a PLC again. It is also good to check from time to time whether program in a PLC has not changed. This helps to avoid hazardous situations in factory rooms (some automakers have established communication networks which regularly check programs in PLC controllers to ensure execution only of good programs). Almost every program for programming a PLC controller possesses various useful options such as: forced switching on and off of the system input/outputs (I/O lines),program follow up in real time as well as documenting a diagram. This documenting is necessary to understand and define failures and malfunctions. Programmer can add remarks, names of input or output devices, and comments that can be useful when finding errors, or with system maintenance. Adding comments and remarks enables any technician (and not just a person who developed the system) to understand a ladder diagram right away. Comments and remarks can even quote precisely part numbers if replacements would be needed. This would speed up a repair of any problems that come up due to bad parts. The old way was such that a person who developed a system had protection on the program, so nobody aside from this person could understand how it was done. Correctly documented ladder diagram allows any technician to understand thoroughly how system functions.Electrical supply is used in bringing electrical energy to central processing unit. Most PLC controllers work either at 24 VDC or 220 VAC. On some PLC controllers you’ll find electrical supply as a separate module. Those are usually bigger PLC controllers, while small and medium series already contain the supply module. User has to determine how much current to take from I/O module to ensure that electrical supply provides appropriate amount of current. Different types of modules use different amounts of electrical current. This electrical supply is usually not used to start external input or output. User has to provide separate supplies in starting PLC controller inputs because then you can ensure so called “pure” supply for the PLC controller. With pure supply we mean supply where industrial environment can not affect it damagingly. Some of the smaller PLC controllers supply their inputs with voltage from a small supply source already incorporated into a PLC.中文翻译：从结构上分，PLC分为固定式和组合式（模块式）两种。

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NET-BASED TASK MANAGEMENT SYSTEM Hector Garcia-Molina, Jeffrey D. Ullman, Jennifer WisdomABSTRACTIn net-based collaborative design environment, design resources become more and more varied and complex. Besides common information management systems, design resources can be organized in connection with design activities.A set of activities and resources linked by logic relations can form a task. A task has at least one objective and can be broken down into smaller ones. So a design project can be separated into many subtasks forming a hierarchical structure.Task Management System (TMS) is designed to break down these tasks and assign certain resources to its task nodes．As a result of decomposition.al1 design resources and activities could be managed via this system.KEY WORDS：Collaborative Design, Task Management System (TMS), Task Decomposition, Information Management System1 IntroductionAlong with the rapid upgrade of request for advanced design methods, more and more design tool appeared to support new design methods and forms. Design in a web environment with multi-partners being involved requires a more powerful and efficient management system .Design partners can be located everywhere over the net with their own organizations. They could be mutually independent experts or teams of tens of employees. This article discusses a task management system (TMS) which manages design activities and resources by breaking down design objectives and re-organizing design resources inconnection with the activities. Comparing with common information management systems (IMS) like product data management system and document management system, TMS can manage the whole design process. It has two tiers which make it much more f1exible in structure.The 1ower tier consists of traditional common IMSS and the upper one fulfills logic activity management through controlling a tree-like structure, allocating design resources and making decisions about how to carry out a design project. Its functioning paradigm varies in different projects depending on the project’s scale and purpose. As a result of this structure, TMS can separate its data model from its logic mode1.It could bring about structure optimization and efficiency improvement, especially in a large scale project.2 Task Management in Net-Based Collaborative DesignEnvironment2.1 Evolution of the Design EnvironmentDuring a net-based collaborative design process, designers transform their working environment from a single PC desktop to LAN, and even extend to WAN. Each design partner can be a single expert or a combination of many teams of several subjects, even if they are far away from each other geographically. In the net-based collaborative design environment, people from every terminal of the net can exchange their information interactively with each other and send data to authorized roles via their design tools. The Co Design Space is such an environment which provides a set of these tools to help design partners communicate and obtain design information. Code sign Space aims at improving the efficiency of collaborative work, making enterprises increase its sensitivity to markets and optimize the configuration of resource.2.2 Management of Resources and Activities in Net-Based Collaborative EnvironmentThe expansion of design environment also caused a new problem of how toorganize the resources and design activities in that environment. As the number of design partners increases, resources also increase in direct proportion. But relations between resources increase in square ratio. To organize these resources and their relations needs an integrated management system which can recognize them and provide to designers in case of they are needed.One solution is to use special information management system (IMS).An IMS can provide database, file systems and in/out interfaces to manage a given resource. For example there are several IMS tools in Co Design Space such as Product Data Management System, Document Management System and so on. These systems can provide its special information which design users want.But the structure of design activities is much more complicated than these IM S could manage, because even a simple design project may involve different design resources such as documents, drafts and equipments. Not only product data or documents, design activities also need the support of organizations in design processes. This article puts forward a new design system which attempts to integrate different resources into the related design activities. That is task management system (TMS).3 Task Breakdown Model3.1 Basis of Task BreakdownWhen people set out to accomplish a project, they usually separate it into a sequence of tasks and finish them one by one. Each design project can be regarded as an aggregate of activities, roles and data. Here we define a task as a set of activities and resources and also having at least one objective. Because large tasks can be separated into small ones, if we separate a project target into several lower—level objectives, we define that the project is broken down into subtasks and each objective maps to a subtask. Obviously if each subtask is accomplished, the project is surely finished. So TMS integrates design activities and resources through planning these tasks.Net-based collaborative design mostly aims at products development. Project managers (PM) assign subtasks to designers or design teams who maylocate in other cities. The designers and teams execute their own tasks under the constraints which are defined by the PM and negotiated with each other via the collaborative design environment. So the designers and teams are independent collaborative partners and have incompact coupling relationships. They are driven together only by theft design tasks. After the PM have finished decomposing the project, each designer or team leader who has been assigned with a subtask become a 1ow-class PM of his own task. And he can do the same thing as his PM done to him, re-breaking down and re-assigning tasks.So we put forward two rules for Task Breakdown in a net-based environment, incompact coupling and object-driven. Incompact coupling means the less relationship between two tasks. When two subtasks were coupled too tightly, the requirement for communication between their designers will increase a lot. Too much communication wil1 not only waste time and reduce efficiency, but also bring errors. It will become much more difficult to manage project process than usually in this situation. On the other hand every task has its own objective. From the view point of PM of a superior task each subtask could be a black box and how to execute these subtasks is unknown. The PM concerns only the results and constraints of these subtasks, and may never concern what will happen inside it.3.2 Task Breakdown MethodAccording to the above basis, a project can be separated into several subtasks. And when this separating continues, it will finally be decomposed into a task tree. Except the root of the tree is a project, all eaves and branches are subtasks. Since a design project can be separated into a task tree, all its resources can be added to it depending on their relationship. For example, a Small-Sized-Satellite.Design (3SD) project can be broken down into two design objectives as Satellite Hardware. Design (SHD) and Satellite-Software-Exploit (SSE). And it also has two teams. Design team A and design team B which we regard as design resources. When A is assigned to SSE and B to SHD. We break down the project as shown in Fig 1.It is alike to manage other resources in a project in this way. So when wedefine a collaborative design project’s task model, we should first claim the project’s targets. These targets include functional goals, performance goals, and quality goals and so on. Then we could confirm how to execute this project. Next we can go on to break down it. The project can be separated into two or more subtasks since there are at 1east two partners in a collaborative project. Either we could separate the project into stepwise tasks, which have time sequence relationships in case of some more complex projects and then break down the stepwise tasks according to their phase-to-phase goals.There is also another trouble in executing a task breakdown. When a task is broken into severa1 subtasks; it is not merely “a simple sum motion” of other tasks. In most cases their subtasks could have more complex relations.To solve this problem we use constraints. There are time sequence constraint (TSC) and logic constraint (LC). The time sequence constraint defines the time relationships among subtasks. The TSC has four different types, FF, FS, SF and SS.F means finish and S presents start. If we say Tabb is FS and lag four days, it means Tb should start no later than four days after Ta is finished.The logic constraint is much more complicated. It defines logic relationship among multiple tasks.Here is given an example:“Task TA is separated into three subtasks, Ta, T b and Tc. But there are two more rules.Tb and Tc can not be executed until Ta is finished.Tb and Tc can not be executed both，that means if Tb was executed, Tc should not be executed, and vice versa. This depends on the result of Ta.”So we say Tb and Tc have a logic constraint. After finishing breaking down the tasks, we can get a task tree as Fig, 2 illustrates.4 TMS Realization4.1 TMS StructureAccording to our discussion about task tree model and task breakdown basis, we can develop a Task Management System (TMS) based on Co Design Spaceusing Java language, JSP technology and Microsoft SQL 2000. The task management system’s structure is shown in Fig. 3.TMS has four main modules namely Task Breakdown, Role Management, Statistics and Query and Data Integration. The Task Breakdown module helps users to work out task tree. Role Management module performs authentication and authorization of access control. Statistics and Query module is an extra tool for users to find more information about their task. The last Data Integration Module provides in/out interface for TMS with its peripheral environment.4.2 Key Points in System Realization4.2.1 Integration with Co Design SpaceCo Design Space is an integrated information management system which stores, shares and processes design data and provides a series of tools to support users. These tools can share all information in the database because they have a universal Data Mode1. Which is defined in an XML (extensible Markup Language) file, and has a hierarchical structure. Based on this XML structure the TMS h data mode1 definition is organized as following.<?xml version= 1.0 encoding= UTF-8’?><!ELEMENT ProductProcessResource (Prcses?, History?，AsBuiltProduct*，ItemsObj?, Changes?, ManufacturerParts?，SupplierParts?，AttachmentsObj? ，Contacts?，PartLibrary?，AdditionalAttributes*)><!ELEMENT Prcses (Prcs+) ><!ELEMENT Prcs (Prcses，PrcsNotes?，PrcsArc*，Contacts?，AdditionalAttributes*，Attachments?)><!ELEM ENT PrcsArc EMPTY><!ELEMENT PrcsNotes(PrcsNote*)><!ELEMENT PrcsNote EMPTY>Notes: Element “Pros” is a task node object, and “Process” is a task set object which contains subtask objects and is belongs to a higher class task object.One task object can have no more than one “Presses”objects. According to this definition, “Prcs”objects are organized in a tree-formation process. The other objects are resources, such as task link object (“Presage”), task notes (“Pros Notes”), and task documents (“Attachments”) .These resources are shared in Co Design database.文章出处：计算机智能研究[J],47卷，2007：647-703基于网络的任务管理系统摘要在网络与设计协同化的环境下，设计资源变得越来越多样化和复杂化。

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