网络传媒科技有限公司的毕业设计 外文翻译正文
网络工程 英文 毕业 设计 论文 文献翻译 无线技术
毕业论文（文献翻译）单位代码01学号_080114601_分类号_ TN92 _密级__________文献翻译无线技术，低功耗传感器网络无线技术，低功耗传感器网络译文正文：加里莱格在发掘无线传感器的潜在应用方面我们几乎没遇见任何困难。
比如说在家庭安全系统方面，无线传感器比有线传感器更易安装。
而无线传感器的安装费用通常只占有线传感器安装费用的80%，这一点用于工业环境方面同样合适。
并且相对于有线传感器而言，无线传感器应用性更强。
虽然，无线传感器需要消耗更多能量，也就是说所需电池的数量会随之增加或更换过于频繁。
再加上对无线传感器由空气传送的数据可靠性的怀疑论，所以无线传感器看起来并不是那么吸引人。
一个被称为ZigBee的低功率无线技术，它是无线传感器方程重写，但是，通过的IEEE 802.15.4无线标准（图1），ZigBee承诺，把无线传感器的一切，从工厂自动化系统延伸到家庭安全系统，消费电子产品中。
与802.15.4的合作下，ZigBee提供的电池寿命可比普通小型电池长几年。
ZigBee设备预计也便宜，有人估计销售价格最终不到3美元每节点，。
由于价格低，他们应该也能适用于无线交换机，无线自动调温器，烟雾探测器等产品。
图1：ZigBee将网络安全和应用服务层添加到PHY和IEEE811.15.4网络通信的MAC层虽然还没有正式规范的ZigBee存在，但ZigBee的前景似乎一片光明。
技术研究公司In-Stat/MDR在它所谓的“谨慎进取”的预测中预测，802.15.4节点和芯片销售将从今天基本上为零，增加到2010年的165万台。
不是所有这些单位都将与ZigBee结合，但大多数可能会。
世界研究公司预测，到2010年射频模块无线传感器出货量4.65亿美量，其中77％是与ZigBee相关的。
从某种意义上说，ZigBee的光明前途在很大程度上是由于其较低的数据速率（20 kbps到250 kbps），而这些数据率则取决于频段频率（图2）。
毕业论文外文翻译格式【范本模板】
因为学校对毕业论文中的外文翻译并无规定，为统一起见,特做以下要求：1、每篇字数为1500字左右，共两篇；2、每篇由两部分组成:译文+原文.3 附件中是一篇范本，具体字号、字体已标注。
外文翻译（包含原文)(宋体四号加粗）外文翻译一（宋体四号加粗）作者：(宋体小四号加粗）Kim Mee Hyun Director, Policy Research & Development Team，Korean Film Council（小四号）出处：(宋体小四号加粗)Korean Cinema from Origins to Renaissance(P358～P340) 韩国电影的发展及前景（标题：宋体四号加粗）1996～现在数量上的增长(正文:宋体小四）在过去的十年间，韩国电影经历了难以置信的增长。
上个世纪60年代，韩国电影迅速崛起，然而很快便陷入停滞状态,直到90年代以后，韩国电影又重新进入繁盛时期。
在这个时期，韩国电影在数量上并没有大幅的增长，但多部电影的观影人数达到了上千万人次。
1996年，韩国本土电影的市场占有量只有23.1%。
但是到了1998年，市场占有量增长到35。
8%，到2001年更是达到了50%。
虽然从1996年开始，韩国电影一直处在不断上升的过程中，但是直到1999年姜帝圭导演的《生死谍变》的成功才诞生了韩国电影的又一个高峰。
虽然《生死谍变》创造了韩国电影史上的最高电影票房纪录，但是1999年以后最高票房纪录几乎每年都会被刷新。
当人们都在津津乐道所谓的“韩国大片”时，2000年朴赞郁导演的《共同警备区JSA》和2001年郭暻泽导演的《朋友》均成功刷新了韩国电影最高票房纪录.2003年康佑硕导演的《实尾岛》和2004年姜帝圭导演的又一部力作《太极旗飘扬》开创了观影人数上千万人次的时代。
姜帝圭和康佑硕导演在韩国电影票房史上扮演了十分重要的角色。
从1993年的《特警冤家》到2003年的《实尾岛》，康佑硕导演了多部成功的电影。
毕设设计类外文翻译
Interior Design Supports Art Education: A Case StudyInterior design, as a field of study, is a rapidly growing area of interest – particularly for teenagers in the United States. Part of this interest stems from the proliferation ofdesign-related reality shows available through television media. Some art educators and curriculum specialists in the nation perceive the study of interior spaces as a ‘practical application’ of the arts.This article discusses an experiential design problem, originally used in higher education interior design studio courses that was modified and shared with students in third grade to address national academic standards. Later, this same project was modified for use with high school students in the educator’s community a nd with international design students in South Korea.Lastly, the project was presented in a workshop to art education students at a higher education institution. The project was modified to address (1) the age group level and (2) a topic relevant to the audience. Goals of the design project were: (1) to explore creative problem-solving, (2) to explore the application of design elements and principles, and (3) to increase student understanding of spatial relationships within an interior environment. Findings indicate that the project supported several visual art standards, including perception and community. This project may be of interest to current and future art educators and others interested in the potential of interior design content supporting art education.IntroductionThe design of interior spaces is a growing area of interest in the United States. Studies indicate that people spend 90 per cent of their time indoors, thereby making the quality design of interiors critical to the health and welfare of the population. Youth have been unconsciously encouraged since their childhood to develop awareness of their personal interior spaces and furnishings through popular storybooks they read that introduce the awareness of scale, proportion and ergonomics at a very young age (e.g. Three Little Bears and Alice in Wonderland). More recently, teens in the United States have become unexpectedly ‘hooked’ on design related reality shows such as Trading Spaces, Changing Rooms and Design on a Dime. Although Trading Spaces was originally intended for adults, according to the Wall Street Journal article titled ‘The Teen-Room Makeover’ (18 October 2002) the audience has more than 125,000 viewers aged 12 to 17 [1]. In support of that finding, a survey conducted in 2003 for a national chain of hardware stores discovered 65 per cent of teens said they have watched home improvement-related television shows [2].Teens seemingly have a growing interest in the design of interior spaces.In the United States in 2002, a qualitative study was developed to determine if interior design subject-matter could support national academic standards in elementary and secondary schools (kindergarten – twelfth grade) [3]. Findings of the study indicated that art educators and curriculum specialists perceived interior design to be supportive in meeting their standards as a type of ‘practical application’ of the arts. Perceptions of the curriculum specialists indicated they were looking for new ways to interpret fine art standards in their existing curriculum and that interior design offered one solution. As a result, the researcher, who was an interior design educator, was encouraged to identify and develop a project or lesson plan that could introduce children and youth to the importance of well-designed interior spaces yet support an art education standard in the nation.This article discusses an experiential interior design project that was modified from an exercise used in the freshman and sophomore college studio classes and shared with students in third grade, high school, and with international students in South Korea by this interior design educator. The educator was later invited to present this project to art education teachers at her university. The project supported several school district visual art standards, including perception and community. It was modified to address (1) the age group level and (2) a topic relevant to the audience. Goals of the design project were: (1) to explore creative problem solving, (2) to explore the application of design elements and principles, and (3) to increase student understanding of spatial relationships within an interior environment. This project may be of interest to current and future art educators and others interested in the potential of interior design content supporting visual art standards.Review of literatureThe review of literature briefly discusses (1) experiential learning theory, (2) findings from a qualitative study involving art educators, and (3) the interior design link with art education. The interior design project description and process of application will follow.Experiential learningExperiential learning theory, as an application of cognitive/perceptual models, is a tool toenhance the cognitive process of students. Specifically, the experiential learning cycleinvolves a concrete experience that leads to observations and reflections then to formation of abstract concepts and generalisations, before finally testing implications from concepts in new situations [4].The Association for Experiential Education defines experiential education astheprocess by which a learner constructs knowledge, skill and value from direct experience [5]. Drengson [6] defines experiential education as the process of practical engagement withconcepts and skills applied in a practical setting and delivered through physical and practical mental activity.One of the key components to enhance student learning is reflection. Dewey [7] suggests that to have meaning, an experience must be combined with thought. Kolb [8] suggests that reflections can offer a potential source of powerful data to link theory to practice. The mental engagement of an experiential learner can involve questioning, investigation, experimentation, curiosity, problem-solving, assuming responsibility, creativity and the construction of meaning [9].Experiential learning offers the spontaneous opportunity for learning, whether from unplanned moments, natural consequences, mistakes or successes [10]. Holistically, it involves not only the cognitive but also any combination of the senses, the emotions, and the physical [11].Qualitative study involving art educatorsIn 2001, a study was conducted to determine if interior design may be supportive tokindergarten – twelfth grade (K–12) teachers in meeting national academic standards,including the arts [12]. To understand perceptions of experts in interior design and elementary and secondary education, five focus group session sand six personal interviews were conducted with interior design educators, practitioners,K–12 teachers (elementary, junior high, and high school levels), national standards curriculum specialists (local and state level), and school-to-career curriculum specialists from June 2001 to April 2002[13].Focus group findings indicated that K–12teachers, at both elementary and secondary levels, felt that interior design could be supportive in meeting visual art standards because youth are frequently analysing their personal and public spaces. Participants described specific examples of interior design materials they currently needed in their course work to include: examples of good and bad interior spaces, information about elements and principles of design as they relate to interior spaces, and hands-on col our wheels of sturdy materials. In addition they requested that the materials be low cost, stimulating,‘touchable’,recyclable, self-contained, and fun. Lesson plans the visual art teachers suggested included:• reinvention of the ‘shoe box’ projec t;• development of well-known stories (The Three Pigs, Three Little Bears, and Alice in Wonderland) into space models to teach proportion and scale. In addition, it was suggestedthe following lesson plan: use of Goldilocks story to analyse ‘client or consumer needs’;• use of a Dr Seuss story (literary passage) to generate a conceptual model that enhances creativity;• study of cultural spaces at the junior high level that would enhance study of personal expression of identity in interiors [14].The visual arts curriculum specialists indicated hat interior design –as a ‘practical application’ should be introduced in elementary levels where there is a ‘small window of opportunity’ to give good information about the visual arts. See Table 1 fo r an example of the visual art standards in kindergarten – third grade levels. One visual art specialist advocated that the design process was more important to teach than a particular design method. He suggested moving students from designing personal spaces – and the study of elements and principles of design – in elementary levels to the analysis of private and public spaces in the junior high level. Then the high school levels could be reserved for additional indepth Exploration.Today, junior high and high school students are quite attracted to design-related reality shows. Over the last five years, the number of designrelated television shows has increased dramatically [15]. Why are these shows so attractive to teens and young adults? Rodriguez [16]has suggested that this interest is linked to the teens need for expression of self andself-identity.An individual’s unique identity is established through personalisation of space, which is critical to overall development of self [17]. Developing a sense of self involves the use of symbols to communicate to others one’s personal underlying identity.Interior design link with art educationIt is not common for interior design to be linked with art education in K–12 grade levels in the United States. However, the Foundation for Interior Design EducationResearch[18]standards and guidelines – the accreditation organization for higher education interior design programmes in the nation – reveal that there are many shared areas between visual arts and interior design (e.g.elements and principles of design).Rasmussen and Wright [19]advocate the need for a new model for art education. The new model should offer youth an aesthetic education that does more than just serve the traditional concerns of established arts curriculum. Experiences indicate that young people try to make sense of their own lives by creating contextual understanding through actively, and intentionally, making connections to signs, perceptions and experiences. This is a challenge to develop a new art education model that creates a balance between social andcontextual needs, knowledge of young people, and theaesthetic medium itself.The study of interior spaces offers one such context for learning in the physical environment.People spend 90 per cent of their time in interior spaces [20]. Youth consciously or unconsciously, analyse and respond to their near environment. They also learn best if they understand why they are learning what they are learning. Application of design and art to everyday life can assist in making connections in student learning, and develop more awareness of good design as well as an appreciation of the arts. Youth need theopportunity to learn more about design and human behavior so they can learn they have choices about how supportive their environments can be. Children can [determine] how design influences their behaviors; howdesign can be used to manipulate behavior; how design can encourage or discourage conversation, establish status, put people in power positions, increase or decrease anxiety [21].Therefore, based on (1) the experiential learning theoretical underpinnings, (2) recommendations made by art educators and curriculum specialists, and (3) a call for a new ways of teaching art education, an interior design educator at a higher education institution modified an experiential design project that involved the use of elements and principles of design and an opportunity for self-expression of personal spaces. The designproblem of the personal space was changed based on the grade level.Case study project descriptionAlthough art educators and curriculum specialists perceived that interior design content could be supportive to visual art standards, it was determined that a case study project needed to be developed and presented to various grade levels. It was also determined that a conceptual model of interior spaces should be used toenhance student creativity and exploration rather than a finite model that would offer too many rules and boundaries. Project descriptionThe experiential interior design project involved the construction of athree-dimensional concept model using 44 triangular and rectangular pieces of cardstock (stiff) paper in a neutral colour [22]. The objective was to discover, manipulate and create interior spaces based on a given design problem (e.g. design your space station on a planet of your choice or design your home in the Rocky Mountains of Colorado). The purpose ofthe project was to encourage students to design a conceptual structure from the interior out, keep-ing in mind the function of the building. The student’s model had to incorporate a minimum of six spaces and three levels to encourage vertical as well as horizontal volumes. All 44 pieces of cardstock had to be used in the finished model, which sometimes posed achallenge to the youth. The cardstock pieces could not be ripped, torn, or pierced. However, they could be bent and shapedaccording to the whim of the student.Flow from one space to another and one level to another was emphasized. The decision-making design process was explained and encouraged.Outcomes consisted of a three-dimensional abstract model which, if successfully executed, demonstrated the break-down of traditional spatial paradigms. Design problemsEach student grade level was given a different design problem based on the academic standards that were to be met in that class. In some cases, several academic standards were addressed at the same time. Two national standards for visual arts in the United States were selected to be supported with this project: communication and perception. The communication standard indicates that students in kindergarten – third grade should recognise the use of the visual arts as a means of communication (e.g. select and use visual images, themes and ideas in their own work). The perception standard indicates that students know, understand and apply elements of visual arts and principles of design (e.g. Identify elements and principles of design).Third grade studentsAfter procuring appropriate permission, the design educator brought volunteer college-age interior design students to the elementary school to help administer the project. Three third grade classes (twenty students in each class) had just finished a science unit on space and orbits and were studying specific visual art standards. The children were asked to design a personal space station on a planet of their choice. The goal was to help students relate the newly learned science information to something in real life (e.g. Their home), yet encourage exploration of visual arts (see Figs. 2–4).Each team of students was given the same 44 pieces of cardstock (all cut out) in a plastic bag, a cardboard base (15” x 15” square) on which to build the model, and cellophane tape to use in constructing the model. To enhance reflection of this experiential project, each team of three students was asked to give a two-minute verbal presentation in front of the class on their finished model. In this manner, they could discuss their design solution and the design educator could assess their use of creativity through design elements and principles.The college students and design educator rotated through the three classrooms of students to answer questions, encourage use of design elements and principles, and applaud their creative exploration. The third grade teachers assisted in supporting the structure of the class and encouraging shy students who were reluctant to begin.It was interesting to observe that the children rarely built the models on their provided classroom tables. Instead,they moved to the floor space, located the base for the model in between team members, and began construction. Each team member assumed a role in the process. One team member seemed t o act as the ‘designer’, one as the ‘builder/construction crew’ and the last as the ‘supplier’ of materials. Students excitedlydiscussed the positioning of the triangular pieces of cardstock in their model, their rooms in their space stations, and the different ways to turn the model to create different vantage points.The teams of third graders had one hour to complete the models. Then their verbal presentations began, interspersed with questions and comments from the design educator and third grade teachers. Informal observations indicatedthat application of design elements and principles was strong – perhaps due to the consistent rectangular and triangular shapes that had been provided – thereby supporting the visual arts perception standard. Manipulation of shapes was innovative. Line, shape and form were used to provide movement through adjoining spaces and offered a sense of verticality. Interior volumes were created that supported human behaveour in interior spaces. For example, one team’s presentation discussed how their space station boasted an exercise room with trampolines to strengthen human muscles that weakened as a result of zero gravity in outer space. The communication standard was supported in their finished models in a couple ways. First there was a theme of design as it relates to protection from foreign objects. For example, one team’s space station on Saturn incorporated a force field to protect it from flying rocks. Other visual themes of security and safety evoked the implementation of security cameras, alien detectors, missile launchers, telescope laboratories, control stations and transport rooms. Another visual theme related to circulation. Circulation within the structure was depicted by the third graders through the use of escalators, stairs, elevators and poles. A third visual theme was unique human needs as they relate to interior spaces. Almost every team’s space station incorporated a room for their mothers! In addition, depending on the students’ personal interests, unique space station features ranged from chemical rooms to sandboxes. It was obvious in their multiple unique design solutions their use of creativity had been explored and enhanced.Evaluation and assessment that took place, after the classes were dismissed, indicated that the third grade teachers perceived that this experiential design project supported the visual arts standards in both the communication and perception components as well as the third grade science academic standard concerning space and orbits. In addition, the experiential component of the project had unexpected results when certain quiet, unassuming students in the class became animated and highly engaged in learning. One teacher shared her excitement with the design educator about a new connection that wasformed with one of students that she had not been able to connect with before the design exercise.High school studentsAfter the case study with the third grade students, it was determined to offer this project to high school students. Diversity students in a nearby community were invited to attend a complimentary design workshop at a local library. The interior design educator was asked to present a design problem that would relate to arteducation (see Figs. 6–8).Their problem was to use the same experiential project and shapes to design and construct a conceptual model of their new home or cabin in the Rocky Mountain region. The same project constraints existed. Due to the students’ ages, discussions took place prior to the exercise about innovative problem-solving, the exploration of creativity and the elements and principles of design used within the design process. Some of these elements and principles included:Scale. Awareness of human scale was addressed to develop understanding of proportion and scale of the structure and interior spaces. Shape. Triangular shapes were deliberately selected to encourage students to break paradigms of rectangular interior spaces.Colour. The cardstock pieces were of a neutral colour to enhance spatial composition rather than draw attention to colour usage or juxtaposition. Volume/Mass. The mass of thethree-dimensional model was important in communicating the use of common elements and principles of design (e.g. line, rhythm). Line. A variety of different lines (e.g. diagonal, horizontal) were investigated in the manipulation of the shapes. Space. Space was created through the manipulation of shapes. Theories of complexity, mystery and refuge within interior spaces were discussed. Informal assessment of the finished design models indicated that the design solutions werevery creative.Later that semester, by invitation, the same design project was taken to college students training to be art educators in a mini-workshop format. The art education students found the exercise effective in enhancing creativity and understanding how interior design can enhance understanding of visual arts.International studentsAlthough there was no intention to meet a national visual arts academic standard at a specific grade level, this same experiential design project was presented in Seoul, South Korea to college-aged international students. The design problem was to use the same 44 pieces to develop a design concept model for acommercial building in Seoul. Language translators were used to help the design educatorintroduce the project, guide the students through the process, and understand their verbal presentations at the end of the workshop.Students commented during and after the workshop how the model enhanced their visual literacy skills (they used different words) and creativity within the context of everyday life. The experiential nature of the workshop was seemingly a pleasure to them (see Figs.9–11).Discussion and conclusionThis interior design case study project was designed to be experiential in nature to enhance student learning of the visual arts. Student and teacher assessment of the various groups indicated enthusiasm for the design project because it enhanced creativity, explored multiple design solutions, related to real life, and increased their understanding of human behaviour within the context of the physical environment. Teacherassessment of the age groups indicated that the project did support visual art standards at the appropriate grade level. In addition, their assessment indicated satisfaction with the manner in which the interior design project encouraged student usage of the design elements and principles and the application of design to everyday living. Several instructors indicated that quiet and shy students in their class became engaged in the learning process, which had not been previously observed. Perception of art educators and art education students was that this project supported a variety of visual art standards such as perception and communication. This interior design case study project can be modified for various age and cultural groups and may be of interest to educators who are interested in working collaboratively with colleagues from other disciplines.Visual art programmes in the United States are being cut from the K–12 curriculum. By linking visual arts to an up-and-coming aesthetic field, such as interior design, there may be new ways to sustain and grow visual art programmes in the nation.References1. Orndoff, K. (2003) ASID American Society of Interior Designers 2003 Strategic Environment Report. Future Impact Education, p. 9.2. Levitz, S. (2004) Teens Hooked on Home Décor, London Free Press (Ontario, CA), 24 June, p. D2.3. Clemons, S. (2002) Collaborative Links with K–12: A Proposed Model Integrating Interior Design with National Education Standards, Journal of Interior Design, Vol. 28, No. 1, pp.40–8.4. Rubin, S. G. (1983) Overcoming Obstacles to Institutionalization of Experiential Learning Programs, New Directions for Experiential Learning, Vol. 20, pp. 43–54.5. Luckman, C. (1996) Defining Experiential Education, Journal of Experiential Education, Vol. 19, No. 1, pp. 6–7.6. Drengson, A. R. (1995) What Means this Experience? in Kraft, R. J. & Sokofs, M. [Eds] The Theory of Experiential Education. Boulder, CO: Association for Experiential Education, pp. 87–93.7. Dewey, J. (1916) Democracy and Education. New York: Macmillan.8. Kolb, D. A. (1984). Experiential Learning: Experience as the Sources of Learning and Development. Englewood Cliffs, NJ: Prentice-Hall.9. Luckmann, C. op. cit.10. Ibid.11. Carver, R. (1996) Theory for Practice: A Framework for Thinking about Experiential Education, Journal of Experiential Education, Vol. 19, No. 1, pp. 8–13.12. Clemons, S. op. cit.13. Ibid.14. Ibid.15. Bien, L. (2003) Renovating how-to TV Shows in a Race to Duplicate Success of ‘Trading Spaces’. The Post Standard (Syracuse, NY), 31 October, p. E1.16. Rodriguez, E. M. (2003) Starting Young, Miami Herald, 28 December, p. H–1.17. Baillie S. & Goeters, P. (1997) Home as a Developmental Environment. Proceedings of the American Association of Housing Educators, New Orleans, LA, pp. 32–6.18. Foundation of Interior Design Education Research (FIDER) home page. Available from URL: / (Accessed 4th January 2005).19. Rasmussen, B & Wright, P. (2001) The theatre workshop as educational space: How imagined reality is voiced and conceived, International Journal of Education & the Arts, Vol. 2, No. 2, pp.1–13.20. Environmental Protection Agency (2006) An Introduction to Indoor Air Quality (online). Available from URL: /iaq/ ia-intro.html (Accessed 26th September 2006).21. InformeDesign (n.d.) Implications, Vol. 1, No. 2, p. 2 (online). Available from URL: /# (Accessed 4th January 2005).22. Curfman, J. & Clemons, S. (1992) From Forty-Four Pieces to a New Spatial Paradigm, in Birdsong, C. [Ed.] Proceedings of the Interior Design Educators Council Southwest Regional Meeting, New Orleans, pp. 2–4./detail/refdetail?tablename=SJWD_U&filename=SJWD00000744102&uid=WEEvR EcwSlJHSldSdnQ0SWZDdUlMV1dWZi9tOGkyYTBaTzBVQjVYeENXYVp4MVRJQjI3cmZRYS9YRmhvdnlxazJRPT 0=$9A4hF_YAuvQ5obgVAqNKPCYcEjKensW4IQMovwHtwkF4VYPoHbKxJw!!Interior Design in Augmented Reality EnvironmentABSTRACTThis article presents an application of Augmented Realitytechnology for interior design. Plus, an Educational InteriorDesign Project is reviewed. Along with the dramatic progress ofdigital technology, virtual information techniques are alsorequired for architectural projects. Thus, the new technology ofAugmented Reality offers many advantages for digitalarchitectural design and construction fields. AR is also beingconsidered as a new design approach for interior design. In an ARenvironment, the virtual furniture can be displayed and modifiedin real-time on the screen, allowing the user to have an interactiveexperience with the virtual furniture in a real-world environment.Here, AR environment is exploited as the new workingenvironment for architects in architectural design works, and thenthey can do their work conveniently as such collaborativediscussion through AR environment. Finally, this study proposesa newmethod for applying AR technology to interior designwork, where a user can view virtual furniture and communicatewith 3D virtual furniture data using a dynamic and flexible userinterface. Plus, all the properties of the virtual furniture can beadjusted using occlusion- based interaction method for a TangibleAugmented Reality. General TermsApplications of computer science in modeling, visualization andmultimedia, graphics and imaging, computer vision, human-computerinteraction, et al.KeywordsAugmented Reality, Tangible AR, CAAD, ARToolKit, Interiordesign.1. INTRODUCTIONVisualizing how a particular table or chair will look in a roombefore it is decorated is a difficult challenge for anyone. Hence,Augmented Reality (AR) technology has been proposed forinterior design applications by few previous authors, for example,Koller, C. Wooward, A. Petrovski; K. Hirokazu, et al. The relateddevices typically include data glassesconnected to a。
毕业设计外文翻译范例
毕业设计外文翻译范例引言在大学生的学习生涯中，毕业设计是一项重要的任务。
它是对学生在大学期间所学知识的综合运用，也是对学生能力的一次全面考核。
外文翻译作为毕业设计的一部分，对于提高学生的英语水平和跨文化交流能力有着重要的作用。
本文将探讨毕业设计外文翻译的重要性、挑战以及解决方法。
毕业设计外文翻译的重要性外文翻译在毕业设计中具有重要的地位和作用。
首先，外文翻译可以帮助学生扩大知识面，并且了解国际上的研究动态和前沿技术。
通过翻译外文文献，学生可以学习到最新的研究成果和方法，为毕业设计提供参考和借鉴。
其次，外文翻译能够提高学生的英语水平。
通过翻译外文文献，学生可以锻炼自己的听、说、读、写能力，提高对英语的理解和应用能力。
在全球化的背景下，具备良好的英语能力对于学生的就业和未来发展具有重要意义。
最后，外文翻译可以培养学生的跨文化交流能力。
在进行外文翻译的过程中，学生需要了解不同文化背景下的表达方式和思维方式，从而更好地与其他文化背景的人进行沟通和交流。
这对于提高学生的跨文化合作能力和全球视野具有重要意义。
毕业设计外文翻译的挑战尽管毕业设计外文翻译具有重要的作用，但也面临一些挑战。
首先，外文翻译需要学生具备良好的英语水平和专业知识。
许多外文文献使用专业术语和复杂的句式，对学生的英语能力和专业知识提出了较高的要求。
同时，外文翻译还要求学生具备良好的分析能力和逻辑思维能力，能够准确理解和表达文献中的内容。
其次，外文翻译需要花费大量的时间和精力。
翻译一篇外文文献需要学生仔细阅读和理解原文，然后进行翻译和校对。
这个过程需要反复推敲和修正，耗费了学生大量的时间和精力。
在繁重的学业任务中，学生可能面临时间不足的问题，影响翻译质量和效率。
最后，外文翻译还可能面临文化差异和语言障碍。
不同的语言和文化有着不同的表达方式和思维方式，学生需要充分理解和融入到原文的语言和文化中，才能进行准确和恰当的翻译。
这对学生的跨文化交流能力提出了较高的要求。
毕业设计(论文)外文资料翻译(学生用)
毕业设计外文资料翻译学院：信息科学与工程学院专业：软件工程姓名： XXXXX学号： XXXXXXXXX外文出处： Think In Java (用外文写)附件： 1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文网络编程历史上的网络编程都倾向于困难、复杂，而且极易出错。
程序员必须掌握与网络有关的大量细节，有时甚至要对硬件有深刻的认识。
一般地，我们需要理解连网协议中不同的“层”（Layer）。
而且对于每个连网库，一般都包含了数量众多的函数，分别涉及信息块的连接、打包和拆包；这些块的来回运输；以及握手等等。
这是一项令人痛苦的工作。
但是，连网本身的概念并不是很难。
我们想获得位于其他地方某台机器上的信息，并把它们移到这儿；或者相反。
这与读写文件非常相似，只是文件存在于远程机器上，而且远程机器有权决定如何处理我们请求或者发送的数据。
Java最出色的一个地方就是它的“无痛苦连网”概念。
有关连网的基层细节已被尽可能地提取出去，并隐藏在JVM以及Java的本机安装系统里进行控制。
我们使用的编程模型是一个文件的模型；事实上，网络连接（一个“套接字”）已被封装到系统对象里，所以可象对其他数据流那样采用同样的方法调用。
除此以外，在我们处理另一个连网问题——同时控制多个网络连接——的时候，Java内建的多线程机制也是十分方便的。
本章将用一系列易懂的例子解释Java的连网支持。
15.1 机器的标识当然，为了分辨来自别处的一台机器，以及为了保证自己连接的是希望的那台机器，必须有一种机制能独一无二地标识出网络内的每台机器。
早期网络只解决了如何在本地网络环境中为机器提供唯一的名字。
但Java面向的是整个因特网，这要求用一种机制对来自世界各地的机器进行标识。
为达到这个目的，我们采用了IP（互联网地址）的概念。
IP以两种形式存在着：(1) 大家最熟悉的DNS（域名服务）形式。
我自己的域名是。
所以假定我在自己的域内有一台名为Opus的计算机，它的域名就可以是。
毕业论文外文翻译两篇
毕业论文外文翻译两篇篇一：毕业论文外文翻译外文资料翻译译文：概述是一个统一的Web开发模型，它包括您使用尽可能少的代码生成企业级Web应用程序所必需的各种服务。
作为.NETFramework的一部分提供。
当您编写应用程序的代码时，可以访问.NETFramework中的类。
您可以使用与公共语言运行库(CLR)兼容的任何语言来编写应用程序的代码，这些语言包括MicrosoftVisualBasic、C#、和J#。
使用这些语言，可以开发利用公共语言运行库、类型安全、继承等方面的优点的应用程序。
包括：∙页和控件框架∙编译器∙安全基础结构∙状态管理功能∙应用程序配置∙运行状况监视和性能功能∙调试支持∙XMLWebservices框架∙可扩展的宿主环境和应用程序生命周期管理∙可扩展的设计器环境页和控件框架是一种编程框架，它在Web服务器上运行，可以动态地生成和呈现网页。
可以从任何浏览器或客户端设备请求网页，会向请求浏览器呈现标记（例如HTML）。
通常，您可以对多个浏览器使用相同的页，因为会为发出请求的浏览器呈现适当的标记。
但是，您可以针对诸如MicrosoftInternetExplorer6的特定浏览器设计网页，并利用该浏览器的功能。
支持基于Web的设备（如移动电话、手持型计算机和个人数字助理(PDA)）的移动控件。
网页是完全面向对象的。
在网页中，可以使用属性、方法和事件来处理HTML元素。
页框架为响应在服务器上运行的代码中的客户端事件提供统一的模型，从而使您不必考虑基于Web的应用程序中固有的客户端和服务器隔离的实现细节。
该框架还会在页处理生命周期中自动维护页及该页上控件的状态。
使用页和控件框架还可以将常用的UI功能封装成易于使用且可重用的控件。
控件只需编写一次，即可用于许多页并集成到网页中。
这些控件在呈现期间放入网页中。
页和控件框架还提供各种功能，以便可以通过主题和外观来控制网站的整体外观和感觉。
可以先定义主题和外观，然后在页面级或控件级应用这些主题和外观。
毕业设计(论文)外文资料及译文(模板
大连东软信息学院
毕业设计（论文）外文资料及译文
系所：
专业：
班级：
姓名：
学号：
大连东软信息学院
Dalian Neusoft University of Information
外文资料和译文格式要求
一、装订要求
1、外文资料原文（复印或打印）在前、译文在后、最后为指导教师评定成绩。
2、译文必须采用计算机输入、打印。
3、A4幅面打印，于左侧装订。
二、撰写要求
1、外文文献内容与所选课题相关。
2、本科学生译文汉字字数不少于4000字，高职学生译文汉字字数不少于2000字。
三、格式要求
1、译文字号：中文小四号宋体，英文小四号“Times New Roman”字型，全文统一，首行缩进2个中文字符，1.5倍行距。
2、译文页码：页码用阿拉伯数字连续编页，字体采用“Times New Roman”字体，字号小五，页底居中。
3、译文页眉：眉体使用单线，页眉说明五号宋体，居中“大连东软信息学院本科毕业设计（论文）译文”。
大连东软信息学院毕业设计（论文）译文
-1-。
外文翻译---网络广告：不同的传媒形式
毕业论文（设计）外文翻译一、外文原文标题：Internet Advertising: The Medium is the Difference原文：IntroductionInternet advertising is growing at an impressive rate. A recent report by Price Waterhouse-Coopers estimates 1998 online ad revenues at $1.92 billion, more than twice those of 1997. By year 2000, it has been projected that ad revenues will grow to a level of $ 4.3 billion (IAB, 1998). This spectacular growth comes as no surprise if one considers that on the one hand, advertisers are always looking for new ways to reach their target audience, and on the other hand, web site operators are always looking for new sources of revenues to finance their ever-mounting operating costs. Indeed, in order to take full advantage of the potential of Internet advertising, and to avoid its pitfalls, one needs to rethink the consumer medium interaction as it applies to Internet advertising.In this article, we show how the underlying full-duplex networked organization of the Internet transforms the traditional one-way relationship between advertisers and consumers that is inherent in standard advertising. On the Internet, content providers take on roles of both conduits and interaction enablers in a two-way interaction with prospective consumers. This new model profoundly affects the relationship between each player. Consumers now interact with both content providers and advertisers. Content providers are not responsible for advertisement fulfillment anymore. It also affects how content providers are compensated for their services. As conduits, their compensation scheme was simple. As relationship creators, their value is harder to assess.least once), Gross Rating Points (GRP = Reach x Frequency), and some demographic information about the reached audience.The information reported to advertisers is generated through surveys or panels of consumers that measure audience viewing, or listening, patterns. For example, in the TV industry, People meter devices are used to monitor TV viewing patterns (i.e., whether a TV set is on or off and what program, if any is tuned at a given point intime), and consequently audience viewing habits, for a representative sample of households. However, for the television medium, content providers have imperfect information about their audiences. This is because marketing research firms are merely able to monitor the TV set patterns of a sample subset of the population rather than the actual viewing patterns of their audiences. Thus, the monitoring of broadcasts does not provide completely accurate information concerning who is tuned in to particular programs. Print media, such as newspapers and magazines, fare a little better in that they can readily estimate the size of their audience from the number of copies they sold. However, they still experience uncertainty as to the characteristics of their audience as they do not readily possess information about consumers who chose to buy their publications at a newsstand rather than those who subscribe. The Advertiser->Content Provider->Consumer framework, which we call broadcast, is very efficient in reaching mass markets. It requires a minimum number of interactions and has been used for more than a century. It is very different from the request-based mode of information dissemination that occurs on the Internet. On the Internet, advertisers still contract with content providers to insert advertisements within the programming offered to consumers. But from this point on, everything is different. First, content providers do not push their content on consumers at pre-established points in time. Rather, they wait for consumers to request the information when they are ready to consume it. Second, content providers do notbroadcast the advertisements linearly along with their content. Rather they send their content to consumers with an instruction to retrieve the appropriate piece of advertisement directly from the advertiser.Advantages of Advertising on the InternetThe multiplicity of interactions that come about by the modus operandi of the Internet creates a wealth of opportunities for marketers (some have called the Internet the Holy Grail of marketers).First of all, since consumers directly request the content they would like to access, it becomes easy (at least theoretically) to measure the size of the audience of a particular ad campaign.Second, since consumers who subscribe to several different content providers displaying the same ad have to request the ad from the advertisers themselves rather than from the content providers, it becomes potentially easy for the advertisers to measure the true frequency of exposure.Third, because the advertiser only serves the actual ad content at the time when the consumer is ready to consume it, advertisers don’t have to commit on the ad content until the last instant. This provides considerable opportunity for tailoring an advertising message to a particular prospective consumer. We now explore some of these opportunities.Accurate measurementNow that consumers and advertisers interact directly on the Internet, great improvements in quality of marketing research can be made by shifting from a survey-based to a census-based method of assessing advertising effectiveness. Figures 1 and 2 suggest the benefits of a censusbased advertising tracking methodology. In figure 1, the advertiser reaches Consumer 1 through both Provider 1 and Provider 2. However, given the lack of consumer level data, all the advertiser knows is that Provider 1 and Provider 2 reach similar demographics. He will have no indication of the actual overlap between the magazines or television stations. In contrast, the Internet advertiser will see Consumer 1 come twice (figure 2), once send by Provider 1 and a second time send by Provider 2. Hence, the advertiser now has an accurate measurement of the number of consumers who see its ad (Reach) and of the number of times each consumer sees the ad (Frequency). The interactive nature of the Internet medium has lead to new criteria for the measurement of advertising effectiveness: "page views" (or impressions) and "click-throughs." Impression represents an opportunity for a surfer to see and click on a banner ad within a publisher's Web page, and click-through represents the committed action of a surfer who actually clicks on a banner ad in response to its message. This immediate measure of advertising response is a new concept that can only be measured on the Internet. Many see it as the ultimate measure of advertising effectiveness.First, it should be noted that ads from standard media come to prospective customers whereas prospective customers on the Internet medium come to ads.Furthermore, in contrast to the mass, or segmented, marketing strategies that are afforded by standard media (e.g., a TV advertisers can focus their efforts on a given demographic or geographic segments), Internet advertising creates the potential opportunity of micro-level marketing. This means that an Internet advertiser can specifically design and tailor a given advertising message to target a particular individual consumer. For example, an advertiser can chose to deliver a specific ad to a given individual only after the individual has exhibited a particular type of behavior (e.g., has expressed a given level of interest in a particular product in view of his origin or previous clickstream history). As such an individual consumer who comes to an advertiser's site for the first time might be given advertising in the form of general product information. In contrast, a repeat visitor might be given more detailed product information in an effort to move him/her towards a product purchase decision. In this web-based environment, the advertiser can decide whether he wants the consumer to see the same ad twice, or see two different ads. Further, by limiting the number of repetitions a consumer is exposed to, advertisers can limit burnout and maximize their return on marketing expenditures.An advertiser also has the ability to tailor the ad campaign to the environment the consumer is involved in at a particular moment. For instance, specific advertising messages can be tailored to specific search engine keywords. Thus, a particular key word (e.g., PC hardware) may be used to generate ads and for PC brands whereas a combination of key words (PC hardware and storage media) might be used to generate ads for CD-ROM, removable hard drives, or DVD drives.ConclusionTo benefit from the unique Internet medium environment, advertisers and managers need to consider the idiosyncrasies of Internet advertising. A unique advantage of the Internet Medium is its bi-directional framework that incorporates two-way links between advertiser and prospective consumers. A beneficial byproduct of this linkage is that customers can be targeted individually at the micro-consumer level. In addition, because of the interactivity afforded by the medium, the advertisercan tailor individual advertising and formulate advertising messages adaptively. Because of the two way flow of information that characterizes the medium, the latter can deliver advertising messages to individual consumers and, at the same time, gather consumer information on a continuous basis as prospective consumers surf the publisher or advertiser's Web sites. The integration of the transaction function within the medium provides for a closing of the marketing-response loop which permits the potential development of appropriate advertising and marketing strategies that will best influence a prospective consumer's purchase behavior.Despite the promises of the Internet as an advertising medium, there are continuing challenges that make the effective implementation of advertising strategy difficult. Measurement problems exist due to lack of standardized advertising unit of measures, measurements, as well as difference in the tracking methodologies that are used by third party companies. Current measurement methods typically have limited accuracy. It is generally not possible to provide measures of ad effectiveness on the Internet that may be appropriately compared with those of standard media. Thus, relative media effectiveness across media, including the Internet, is difficult to assess. The different methods of pricing advertising on the Internet (on the basis of impressions or click-throughs) also make it difficult to assess the cost/effectiveness of advertising in this new medium and thus hamper the implementation of advertising budgeting.Because Internet advertising involves a partial allocation of bandwidth to advertising messages, it is more difficult to draw a prospective consumer's attention to an ad on the Internet as it is shared with other contents including potentially competing ads on the same Web page. This suggests that ad design and placement aspects may be of great importance to insure that a consumer will be drawn to the banner ad. This means that it is important for advertisers to gain a greater understanding about how prospective consumers process information, including ads, on Web pages.In sum, there are great opportunities for advertisers on the Internet. However, as was pointed out, considerable challenges still remain. Nevertheless, it is expected thatthe opportunities and promises of the Web will be realized as advertisers and researchers continue to gain a better understanding of the unique characteristics of the Web as a medium as well as the nature of consumer search and response behavior on the Web.出处：Xavier Drèze Fred Zufryden 【J】Markets and Culture, 2000 October 4, 1999二、翻译文章标题：网络广告：不同的传媒形式译文：介绍网络广告正在以惊人的速度增长，PriceWaterhouse-Coopers公司最近的一份报告估计1998年网络广告的收入达到1.92亿美元，超过1997年的两倍。
网络广告-毕业论文-英文文献翻译
Discuss On Online AdvertisingJack Farnlinfrom Princeton UnversityOnline advertising is a form of promotion that uses the Internet and World Wide Web for the expressed purpose of delivering marketing messages to attract customers. Examples of online advertising include contextual ads on search engine results pages, banner ads, Rich Media Ads, Social network advertising, online classified advertising, advertising networks and e-mail marketing, including e-mail spam.Online advertising is an emerging advertising media, from 1997 China online advertising was born, online advertising development is rapid, paid search advertising become network advertisement new growth point. Compared with the similar foreign market, China's network advertisement market is still behind many, but the market has great potential. Form and creative backward, advertising regulatory basic lack, China's online advertising market existing main problems. Later, Chinese online advertising to "two-way interaction" the direction of development, meanwhile, and traditional media integration will further strengthen.After data access network advertisement, learned some basic knowledge, grasps the network advertisement, situation and development trend of the network advertisement is the development trend of stud. This paper points out the Chinese Internet advertising the problems and proposes the perfecting of net ads scientific management method. Through chart to China Internet advertising status and developing trends are analyzed and summarized. Through the analysis of the Chinese Internet advertising marketcharacteristics, Chinese Internet advertising, the present situation of and problems existing in some ideas to solve the problem. Internet advertising development situation, it is modern unstoppable advertising the inheritance and development of, become the emerging advertising media.Competitive advantage over traditional advertising:One major benefit of online advertising is the immediate publishing of information and content that is not limited by geography or time. To that end, the emerging area of interactive advertising presents fresh challenges for advertisers who have hitherto adopted an interruptive strategy. Another benefit is the efficiency of advertiser's investment. Online advertising allows for the customization of advertisements, including content and posted websites. For example, AdWords and AdSense enable ads shown on relevant webpages or aside of search results of pre-chosen keywords. Another is the payment method. Whatever purchasing variation is selected, the payment is usually relative with audiences' response.Purchasing variations:The three most common ways in which online advertising is purchased are CPM, CPC, and CPA.CPM (Cost Per Impression) is where advertisers pay for exposure of their message to a specific audience. CPM costs are priced per thousand impressions, or loads of an advertisement. However, some impressions may not be counted, such as a reload or internal user action. The M in the acronym is the Roman numeral for one thousand.CPV (Cost Per Visitor) or (Cost per View in the case of Pop Ups and Unders) is where advertisers pay for the delivery of a Targeted Visitor to the advertisers website.CPC (Cost Per Click) is also known as Pay per click (PPC). Advertisers pay each time a user clicks on their listing and is redirected to their website. They do not actually pay for the listing, but only when the listing is clicked on. This system allows advertising specialists to refine searches and gain information about their market. Under the Pay per click pricing system, advertisers pay for the right to be listed under a series of target rich words that direct relevant traffic to their website, and pay only when someone clicks on their listing which links directly to their website. CPC differs from CPV in that each click is paid for regardless of whether the user makes it to the target site.CPA (Cost Per Action) or (Cost Per Acquisition) advertising is performance based and is common in the affiliate marketing sector of the business. In this payment scheme, the publisher takes all the risk of running the ad, and the advertiser pays only for the amount of users who complete a transaction, such as a purchase or sign-up. This is the best type of rate to pay for banner advertisements and the worst type of rate to charge. Similarly, CPL (Cost Per Lead) advertising is identical to CPA advertising and is based on the user completing a form, registering for a newsletter or some other action that the merchant feels will lead to a sale. Also common, CPO (Cost Per Order) advertising is based on each time an order is transacted.Cost per conversion Describes the cost of acquiring a customer, typically calculated by dividing the total cost of an ad campaign by the number of conversions. The definition of "Conversion" varies depending on the situation: it is sometimes considered to be a lead, a sale, or a purchase. CPE (Cost Per Engagement) is a form of Cost Per Action pricing first introduced in March 2008. Differing from cost-per-impression orcost-per-click models, a CPE model means advertising impressions are free and advertisers pay only when a user engages with their specific ad unit. Engagement is defined as a user interacting with an ad in any number of ways. Though, as seen above, the large majority of online advertising has a cost that is brought about by usage or interaction of an ad, there are a few other methods of advertising online that only require a one time payment. The Million Dollar Homepage is a very successful example of this. Visitors were able to pay $1 per pixel of advertising space and their advert would remain on the homepage for as long as the website exists with no extra costs. Floating ad: An ad which moves across the user's screen or floats above the content.Expanding ad: An ad which changes size and which may alter the contents of the webpage.Polite ad: A method by which a large ad will be downloaded in smaller pieces to minimize the disruption of the content being viewedWallpaper ad: An ad which changes the background of the page being viewed. Trick banner: A banner ad that looks like a dialog box with buttons. It simulates an error message or an alert.Pop-up: A new window which opens in front of the current one, displaying an advertisement, or entire webpage.Pop-under: Similar to a Pop-Up except that the window is loaded or sent behind the current window so that the user does not see it until they close one or more active windows.Video ad: similar to a banner ad, except that instead of a static or animated image, actual moving video clips are displayed.Map ad: text or graphics linked from, and appearing in or over, a location on an electronic map such as on Google Maps.Mobile ad: an SMS text or multi-media message sent to a cell phone.In addition, ads containing streaming video or streaming audio are becoming very popular with advertisers.E-mail advertisingLegitimate Email advertising or E-mail marketing is often known as "opt-in e-mail advertising" to distinguish it from spam.Affiliate marketingAffiliate marketing was an invention by in 1994 and was excelled by when it launched its Affiliate Program, called Associate Program in 1996. The online retailer used its program to generate low cost brand exposure and provided at the same time small websites a way to earn some supplemental income.Contextual advertisingMany advertising networks display graphical or text-only ads that correspond to the keywords of an Internet search or to the content of the page on which the ad is shown. These ads are believed to have a greater chance of attracting a user, because they tend to share a similar context as the user's search query. For example, a search query for "flowers" might return an advertisement for a florist's website.Another newer technique is embedding keyword hyperlinks in an article which are sponsored by an advertiser. When a user follows the link, they are sent to a sponsor's website.Behavioral targetingIn addition to contextual targeting, online advertising can be targeted based on a user's past clickstream. For example, if a user is known to have recently visited a number of automotive shopping / comparison sites based on clickstream analysis enabled by cookies stored on the user's computer, that user can then be served auto-related ads when they visit other,non-automotive sites.Ads and malwareThere is also class of advertising methods which may be considered unethical and perhaps even illegal. These include external applications which alter system settings (such as a browser's home page), spawn pop-ups, and insert advertisements into non-affiliated webpages. Such applications are usually labeled as spyware or adware. They may mask their questionable activities by performing a simple service, such as displaying the weather or providing a search bar. Some programs are effectively trojans. These applications are commonly designed so as to be difficult to remove or uninstall. Theever-increasing audience of online users, many of whom are not computer-savvy, frequently lack the knowledge and technical ability to protect themselves from these programs.On the status of China's online advertising and Development sumti Sarkar Department of Information Management, Lancaster University Key words：online advertising, Internet, Development Abstract With the Internet economy, online advertising came into being. The late 20th century, the Internet swept the world, more and more people are beginning to realize networks with the media features, so the "fourth media" the word began to frequently appear in daily life. Although online advertising is still a small market share, but as the fourth medium of the Internet development Querang traditionalmedia dare not ignore. Because its growth rate far exceeds other types of media. This article about online advertising in China's situation and development trend.Internet advertising is the main features are:1 extensiveness and open: the network advertisement can advertising information through Internet all-weather, 24 hours uninterruptedly spreads to the world, these effects are traditional media can achieve. In addition, newspapers, magazines, television, radio, and trafflc signs such traditional advertising has a great compulsive, and network advertising process is open, the mandatory, this point with traditional media have a very different nature.2. Real-time and controllability: network advertisement may according to the customer demand rapid manufacture and launch, while the traditional advertising production cost is high, dropping cycle fixed. Moreover, in the traditional media advertising on hard to change, even after publication can change also often needs to pay big economic costs, and network advertisement can according to customer needs to be changed in the contents of advertisements. So, advertisers business decision-making changes can timely implementation and promotion.3. Directness and pertinence: through traditional advertising, consumers only indirectly touch the promotional products, not through advertising feel directly products or understand the manufacturer of the specific operation and service provision. While Internet advertising is different, as long as consumers saw interested content, directly click, and then enter into this enterprise website, understands the specific contents of the business. In addition, the network advertisement can launch to some specific target groups,even can do one-on-one directional issuance. According to the characteristics of different visitors, online advertising can be flexibly achieve time orientation, regional orientation, channel directional, thus fulfilling the consumer clear classified in a certain extent, guarantee the advertisement's arrival rate.4. Biphasic and interactivity: the traditional advertising information flow is one-sided, namely enterprise launched what content, consumer can passively accept what content. While the mono-direction network advertisement breakthrough the limitations of both sides, realizing the supply and demand of information flow two-way interaction. Through the Internet advertising links, users can from the manufacturer of websites related to get more and more detailed information. In addition, users can pass AD position directly fill out and submit online form information, the manufacturer can always get precious user feedback information. Meanwhile, the network advertisement can provide further inquiries, convenient and product consumer interaction and communication.5. Easy statistical and can be assessed sex: in traditional media advertising, it is difficult to know exactly how many people receive advertising messages. While Internet advertising different, can detailed statistical a website each page is being viewed total number, the number of each advertising is clicked, and even detailed, specifically every visitor statistics shows the access time and IP address. In addition, provide network advertising website can usually build user database, including users geographic distribution, age, gender, income, occupation, marital status, hobbies, etc. These statistics can help advertisers statistics and analysis the market and the audience, according to the characteristics of advertising target audience,pertinently put ads, and according to the user's characteristics offixed-point launch and tracking analysis, the advertisement effect makes objective accurate assessment.In a word, No matter electronic commerce or Internet advertising are closely related to internet and the development of internet. Therefore, with the development of the internet economy, the internet advertisement surely can along with its large development.网络广告探讨Jack Farnlin普林斯顿大学网络广告是发布在英特网和万维网上,来达到传播市场信息，吸引消费者的目的的一种促销形式。
网站毕业设计外文翻译
WebsiteFrom Wikipedia, the free encyclopediaA website is a collection of related web pages, images, videos or other digital assets that are addressed relative to a common Uniform Resource Locator (URL), often consisting of only the domain name, or the IP address, and the root path in an Internet Protocol-based network. A web site is hosted on at least one web server, accessible via a network such as the Internet or a private local area network.A web page is a document, typically written in plain text interspersed with formatting instructions of Hypertext Markup Language (HTML, XHTML).A web page may incorporate elements from other websites with suitable markup anchors.Web pages are accessed and transported with the Hypertext Transfer Protocol (HTTP), which may optionally employ encryption (HTTP Secure, HTTPS) to provide security and privacy for the user of the web page content. The user's application, often a web browser, renders the page content according to its HTML markup instructions onto a display terminal.All publicly accessible websites collectively constitute the World Wide Web.the pages of a website can usually be accessed from a simple Uniform Resource Locator called the homepage. The URLs of the pages organize them into a hierarchy, although hyperlinking between them conveys the reader's perceived site structure and guides the reader's navigation of the site.Some websites require a subscription to access some or all of their content. Examples of subscription sites include many business sites, parts of many news sites, academic journal sites, gaming sites, message boards, web-based e-mail, social networking websites, and sites providing real-time stock market data.1.HistoryThe World Wide Web (WWW) was created in 1989 by CERN physicist Tim Berners-Lee.On 30 April 1993, CERN announced that the World Wide Web would be free to use for anyone.Before the introduction of HTML and HTTP, other protocols such as filetransfer protocol and the gopher protocol were used to retrieve individual files from a server. These protocols offer a simple directory structure which the user navigates and chooses files to download. Documents were most often presented as plain text files without formatting or were encoded in word processor formats.2.OverviewOrganized by function, a website may be（1）a personal website（2）a commercial website（3）a government website（4）a non-profit organization websiteIt could be the work of an individual, a business or other organization, and is typically dedicated to some particular topic or purpose. Any website can contain a hyperlink to any other website, so the distinction between individual sites, as perceived by the user, may sometimes be blurred.Websites are written in, or dynamically converted to HTML (Hyper Text Markup Language) and are accessed using a software interface classified as a user agent. Web pages can be viewed or otherwise accessed from a range of computer-based and Internet-enabled devices of various sizes, including desktop computers, laptops, PDAs and cell phones.A website is hosted on a computer system known as a web server, also called an HTTP server, and these terms can also refer to the software that runs on these systems and that retrieves and delivers the web pages in response to requests from the website users. Apache is the most commonly used web server software (according to Netcraft statistics) and Microsoft's Internet Information Server (IIS) is also commonly used.3. Static websiteA static website is one that has web pages stored on the server in the format that is sent to a client web browser. It is primarily coded in Hypertext Markup Language (HTML).Simple forms or marketing examples of websites, such as classic website, a five-page website or a brochure website are often static websites, because they present pre-defined, static information to the user. This may includeinformation about a company and its products and services via text, photos, animations, audio/video and interactive menus and navigation.This type of website usually displays the same information to all visitors. Similar to handing out a printed brochure to customers or clients, a static website will generally provide consistent, standard information for an extended period of time. Although the website owner may make updates periodically, it is a manual process to edit the text, photos and other content and may require basic website design skills and software.In summary, visitors are not able to control what information they receive via a static website, and must instead settle for whatever content the website owner has decided to offer at that time.They are edited using four broad categories of software:(1) Text editors, such as Notepad or TextEdit, where content and HTML markup are manipulated directly within the editor program(2) Wysiwyg offline editors, such as Microsoft FrontPage and Adobe Dreamweaver (previously Macromedia Dreamweaver), with which the site is edited using a GUI interface and the final HTML markup is generated automatically by the editor software(3) Wysiwyg online editors which create media rich online presentation like web pages, widgets, intro, blogs, and other documents.(4) Template-based editors, such as Rapidweaver and iWeb, which allow users to quickly create and upload web pages to a web server without detailed HTML knowledge, as they pick a suitable template from a palette and add pictures and text to it in a desktop publishing fashion without direct manipulation of HTML code.4. Dynamic websiteA dynamic website is one that changes or customizes itself frequently and automatically, based on certain criteria.Dynamic websites can have two types of dynamic activity: Code and Content. Dynamic code is invisible or behind the scenes and dynamic content is visible or fully displayed.(1) Dynamic codeThe first type is a web page with dynamic code. The code is constructed dynamically on the fly using active programming language instead of plain,static HTML.A website with dynamic code refers to its construction or how it is built, and more specifically refers to the code used to create a single web page. A dynamic web page is generated on the fly by piecing together certain blocks of code, procedures or routines. A dynamically-generated web page would call various bits of information from a database and put them together in a pre-defined format to present the reader with a coherent page. It interacts with users in a variety of ways including by reading cookies recognizing users' previous history, session variables, server side variables etc., or by using direct interaction (form elements, mouse overs, etc.). A site can display the current state of a dialogue between users, monitor a changing situation, or provide information in some way personalized to the requirements of the individual user.(2) Dynamic contentThe second type is a website with dynamic content displayed in plain view. Variable content is displayed dynamically on the fly based on certain criteria, usually by retrieving content stored in a database.A website with dynamic content refers to how its messages, text, images and other information are displayed on the web page and more specifically how its content changes at any given moment. The web page content varies based on certain criteria, either pre-defined rules or variable user input. For example, a website with a database of news articles can use a pre-defined rule which tells it to display all news articles for today's date. This type of dynamic website will automatically show the most current news articles on any given date. Another example of dynamic content is when a retail website with a database of media products allows a user to input a search request for the keyword Beatles. In response, the content of the web page will spontaneously change the way it looked before, and will then display a list of Beatles products like CD's, DVD's and books.5. Software systemsThere is a wide range of software systems, such as Java Server Pages (JSP), the PHP and Perl programming languages, Active Server Pages (ASP), Yuma and ColdFusion (CFML) that are available to generate dynamic web systems and dynamic sites. Sites may also include content that is retrievedfrom one or more databases or by using XML-based technologies such as RSS.Static content may also be dynamically generated either periodically, or if certain conditions for regeneration occur (cached) in order to avoid the performance loss of initiating the dynamic engine on a per-user or per-connection basis.Plugins are available to expand the features and abilities of web browsers, which use them to show active content, such as Microsoft Silverlight, Adobe Flash, Adobe Shockwave or applets written in Java. Dynamic HTML also provides for user interactivity and real time element updating within web pages (ie pages don't have to be loaded or reloaded to effect any changes), mainly using the Document Object Model (DOM) and JavaScript, support which is built-in to most modern web browsers.Turning a website into an income source is a common practice for web developers and website owners. There are several methods for creating a website business which fall into two broad categories, as defined below.(1) Content-based siteSome websites derive revenue by selling advertising space on the site (see Contextual advertising).(2) Product- or service-based sitesSome websites derive revenue by offering products or services for sale. In the case of e-commerce websites, the products or services may be purchased at the website itself, by entering credit card or other payment information into a payment form on the site. While most business websites serve as a shop window for existing brick and mortar businesses, it is increasingly the case that some websites are businesses in their own right; that is, the products they offer are only available for purchase on the web.Websites occasionally derive income from a combination of these two practices. For example, a website such as an online auctions website may charge the users of its auction service to list an auction, but also display third-party advertisements on the site, from which it derives further income.网站文章来自维基百科，自由的百科全书网站是一组相关的网页，图片，视频或其他数字资产的集合，是针对相对的一个共同的统一资源定位符（URL），这个定位器往往由域名，或组成的IP地址在以网络为基础的互联网协议上的根路径构成。
毕业设计论文翻译（译文+原文）
Hacking tricks toward security on network environments Tzer-Shyong Chen1, Fuh-Gwo Jeng 2, and Yu-Chia Liu 11 Department of Information Management, Tunghai University, Taiwan2 Department of Applied Mathematics, National Chiayi University, TaiwanE-Mail:****************.edu.twAbstractMounting popularity of the Internet has led to the birth of Instant Messaging, an up-and-coming form of Internet communication. Instant Messaging is very popular with businesses and individuals since it has instant communication ability. As a result, Internet security has become a pressing and important topic for discussion. Therefore, in recent years, a lot of attention has been drawn towards Internet security and the various attacks carried out by hackers over the Internet. People today often handle affairs via the Internet. For instance, instead of the conventional letter, they communicate with others by e-mails; they chat with friends through an instant messenger; find information by browsing websites instead of going to the library; perform e-commerce transactions through the Internet, etc. Although the convenience of the Internet makes our life easier, it is also a threat to Internet security. For instance, a business email intercepted during its transmission may let slip business confidentiality; file transfers via instant messengers may also be intercepted, and then implanted with backdoor malwares; conversations via instant messengers could be eavesdropped. Furthermore, ID and password theft may lose us money when using Internet bank service. Attackers on the Internet use hacking tricks to damage systems while users are connected to the Internet. These threats along with possible careless disclosure of business information make Instant Messaging a very unsafe method of communication for businesses. The paper divides hacking tricks into three categories: (1) Trojan programs that share files via instant messenger. (2) Phishing or fraud via e-mails. (3) Fake Websites. Keywords:Hacking tricks, Trojan programs, Phishing, Firewall, Intrusion detection system.1. IntroductionIncreasingly more people are using instant messengers such as MSN Messenger, Yahoo! Messenger, ICQ, etc as the media of communication. These instant messengers transmit alphanumeric message as well as permit file sharing. During transfer, a file may be intercepted by a hacker and implanted with backdoor malware. Moreover, the e-mails users receive every day may include Spam, advertisements, and fraudulent mail intended to trick uninformed users. Fake websites too are prevalent. Websites which we often visit could be counterfeited by imitating the interface and the URL of the original, tricking users. The paper classifies hacking tricks into three categories which are explained in the following sections.2. Hacking TricksThe paper divides hacking tricks into three categories: (1) Trojan programs that share files via instant messenger. (2) Phishing (3) Fake Websites.2.1 Trojan programs that share files via instant messengerInstant messaging allows file-sharing on a computer [9]. All present popular instant messengers have file sharing abilities, or allow users to have the above functionality by installing patches or plug-ins; this is also a major threat to present information security. These communication softwares also makeit difficult for existing hack prevention methods to prevent and control information security. Therefore, we shall discuss how to control the flow of instant messages and how to identify dangerous user behavior.Hackers use instant communication capability to plant Trojan program into an unsuspected program; the planted program is a kind of remotely controlled hacking tool that can conceal itself and is unauthorized. The Trojan program is unknowingly executed, controlling the infected computer; it can read, delete, move and execute any file on the computer. The advantages of a hacker replacing remotely installed backdoor Trojan programs [1] with instant messengers to access files are:When the victim gets online, the hacker will be informed. Thus, a hacker can track and access the infected computer, and incessantly steal user information.A hacker need not open a new port to perform transmissions; he can perform his operations through the already opened instant messenger port.Even if a computer uses dynamic IP addresses, its screen name doesn’t change.Certain Trojan programs are designed especially for instant messengers. These Trojans can change group settings and share all files on the hard disk of the infected computer. They can also destroy or modify data, causing data disarray. This kind of program allows a hacker access to all files on an infected computer, and thus poses a great threat to users. The Trojan program takes up a large amount of the resources of the computer causing it to become very slow and often crashes without a reason.Trojan programs that access a user computer through an instant messenger are probably harder to detect than classic Trojan horse programs. Although classic Trojan intrudes a computer by opening a listening or outgoing port which is used to connect toa remote computer, a desktop firewall can effectively block such Trojans. Alternatively, since it is very difficult for the server’s firewall to spot intrusion by controlling an instant messenger’s flow, it is extremely susceptible to intrusion.Present Trojan programs have already successfully implemented instant messengers. Some Trojan programs are Backdoor Trojan, AIMVision, and Backdoor. Sparta.C. Backdoor Trojans use ICQ pager to send messages to its writer. AIMVision steals AIM related information stored in the Windows registry, enabling a hacker to setup an AIM user id. Backdoor. Sparta.C uses ICQ to communicate with its writer and opens a port on an infected host and send its IP Address to the hacker, and at the same time attempts to terminate the antivirus program or firewall of the host.2.1.1 Hijacking and ImpersonationThere are various ways through which a hacker can impersonate other users [7]. The most commonly used method is eavesdropping on unsuspecting users to retrieve user accounts, passwords and other user related information.The theft of user account number and related information is a very serious problem in any instant messenger. For instance, a hacker after stealing a user’s information impersonate the user; the user’s contacts not knowing that the user’s account has been hacked believe that the person they’re talking to is the user, and are persuaded to execute certain programs or reveal confidential information. Hence, theft of user identity not only endangers a user but also surrounding users. Guarding against Internet security problems is presently the focus of future research; because without good protection, a computer can be easily attacked, causing major losses.Hackers wishing to obtain user accounts may do so with the help of Trojans designed to steal passwords. If an instant messenger client stores his/her password on his/her computer, then a hacker can send a Trojan program to the unsuspecting user. When the user executes the program, the program shall search for the user’s password and send it to the hacker. There are several ways through which a Trojan program can send messages back to the hacker. The methods include instant messenger, IRC, e-mails, etc.Current four most popular instant messengers are AIM, Yahoo! Messenger, ICQ, and MSN Messenger, none of which encrypts its flow. Therefore, a hackercan use a man-in-the-middle attack to hijack a connection, then impersonate the hijacked user and participate in a chat-session. Although difficult, a hacker can use the man-in-the-middle attack to hijack the connection entirely. For example, a user may receive an offline message that resembles that sent by the server, but this message could have been sent by the hacker. All at once, the user could also get disconnected to the server. Furthermore, hackers may also use a Denial of Service (DoS) tool or other unrelated exploits to break the user’s connection. However, the server keeps the connection open, and does not know that the user has been disconnected; thus allowing the hacker to impersonate the user. Moreover, since the data flow is unencrypted and unauthenticated, a hacker can use man-in-the-middle attacks that are similar to that of ARP fraud to achieve its purpose.2.1.2 Denial of Service (DoS)There are many ways through which a hacker can launch a denial of service (DoS) attack [2] on an instant messenger user. A Partial DoS attack will cause a user end to hang, or use up a large portion of CPU resources causing the system to become unstable.Another commonly seen attack is the flooding of messages to a particular user. Most instant messengers allow the blocking of a particular user to prevent flood attacks. However, a hacker can use tools that allow him to log in using several different identities at the same time, or automatically create a large number of new user ids, thus enabling a flood attack. Once a flood attack begins, even if the user realizes that his/her computer has been infected, the computer will not be able to respond. Thus, the problem cannot be solved by putting a hacker’s user id on the ignore list of your instant messenger.A DoS attack on an instant messenger client is only a common hacking tool. The difficulty of taking precautions against it could turn this hacking tool into dangerous DoS type attacks. Moreover, some hacking tools do not just cause an instant messenger client to hang, but also cause the user end to consume large amount of CPU time, causing the computer to crash.2.1.3 Information DisclosureRetrieving system information through instant messenger users is currently the most commonly used hacking tool [4]. It can effortlessly collect user network information like, current IP, port, etc. IP address retriever is an example. IP address retrievers can be used to many purposes; for instance, a Trojan when integrated with an IP address retriever allows a hacker to receive all information related to the infected computer’s IP address as soon as the infected computer connects to the internet. Therefore, even if the user uses a dynamic IP address, hackers can still retrieve the IP address.IP address retrievers and other similar tools can also be used by hackers to send data and Trojans to unsuspecting users. Hackers may also persuade unsuspecting users to execute files through social engineering or other unrelated exploits. These files when executed search for information on the user’s computer and sends them back to the hacker through the instant messenger network.Different Trojan programs were designed for different instant messaging clients. For example, with a user accounts and password stealing Trojans a hacker can have full control of the account once the user logs out. The hacker can thus perform various tasks like changing the password and sending the Trojan program to all of the user’s contacts.Moreover, Trojans is not the only way through which a hacker can cause information disclosure. Since data sent through instant messengers are unencrypted, hackers can sniff and monitor entire instant messaging transmissions. Suppose an employee of an enterprise sends confidential information of the enterprise through the instant messenger; a hacker monitoring the instant messaging session can retrieve the data sent by the enterprise employee. Thus, we must face up to the severity of the problem.2.2 PhishingThe word “Phishing” first appeared in 1996. It is a variant of ‘fishing’, and formed by replacing the ‘f’ in ‘fishing’ with ‘ph’ from phone. It means tricking users of their money through e-mails.Based on the statistics of the Internet Crime Complaint Center, loss due to internet scam was as high as $1.256 million USD in 2004. The Internet Crime Complaint Center has listed the above Nigerian internet scam as one of the ten major internet scams.Based on the latest report of Anti-Phishing Working Group (APWG) [8], there has been a 28% growth of Phishing scams in the past 4 months, mostly in the US and in Asia. Through social engineering and Trojans, it is very difficult for a common user to detect the infection.To avoid exploitation of your compassion, the following should be noted:(1)When you need to enter confidentialinformation, first make sure that theinformation is entered via an entirely secureand official webpage. There are two ways todetermine the security of the webpage:a.The address displayed on the browserbegins with https://, and not http://. Payattention to if the letter ‘s’ exists.b.There is a security lock sign on the lowerright corner of the webpage, and whenyour mouse points to the sign, a securitycertification sign shall appear.(2)Consider installing a browser security softwarelike SpoofStick which can detect fake websites.(3)If you suspect the received e-mail is a Phishinge-mail, do not open attachments attached to theemail. Opening an unknown attachment couldinstall malicious programs onto your computer.(4)Do not click on links attached to your emails. Itis always safer to visit the website through theofficial link or to first confirm the authenticityof the link. Never follow or click on suspiciouslinks in an e-mail. It is advisable to enter theURL at the address bar of the web browser,and not follow the given link.Generally speaking, Phishing [3] [5] is a method that exploits people’s sympathy in the form of aid-seeking e-mails; the e-mail act as bait. These e-mails usually request their readers to visit a link that seemingly links to some charitable organization’s website; but in truth links the readers to a website that will install a Trojan program into the reader’s computer. Therefore, users should not forward unauthenticated charity mails, or click on unfamiliar links in an e-mail. Sometimes, the link could be a very familiar link or an often frequented website, but still, it would be safer if you’d type in the address yourself so as to avoid being linked to a fraudulent website. Phisher deludes people by using similar e-mails mailed by well-known enterprises or banks; these e-mails often asks users to provide personal information, or result in losing their personal rights; they usually contain a counterfeit URL which links to a website where the users can fillin the required information. People are often trapped by phishing due to inattentionBesides, you must also be careful when using a search engine to search for donations and charitable organizations.2.3 Fake WebsitesFake bank websites stealing account numbers and passwords have become increasingly common with the growth of online financial transactions. Hence, when using online banking, we should take precautions like using a secure encrypted customer’s certificate, surf the net following the correct procedure, etc.There are countless kinds of phishing baits, for instance, messages that say data expired, data invalid, please update data, or identity verification intended to steal account ID and matching password. This typeof online scam is difficult for users to identify. As scam methods become finer, e-mails and forged websites created by the impostor resemble their original, and tremendous losses arise from the illegal transactions.The following are methods commonly used by fake websites. First, the scammers create a similar website homepage; then they send out e-mails withenticing messages to attract visitors. They may also use fake links to link internet surfers to their website. Next, the fake website tricks the visitors into entering their personal information, credit card information or online banking account number and passwords. After obtaining a user’s information, the scammers can use the information to drain the bank accounts, shop online or create fake credit cards and other similar crimes. Usually, there will be a quick search option on these fake websites, luring users to enter their account number and password. When a user enters their account number and password, the website will respond with a message stating that the server is under maintenance. Hence, we must observe the following when using online banking:(1)Observe the correct procedure for entering abanking website. Do not use links resultingfrom searches or links on other websites.(2)Online banking certifications are currently themost effective security safeguard measure. (3)Do not easily trust e-mails, phone calls, andshort messages, etc. that asks for your accountnumber and passwords.Phishers often impost a well-known enterprise while sending their e-mails, by changing the sender’s e-mail address to that of the well known enterprise, in order to gain people’s trust. The ‘From’ column of an e-mail is set by the mail software and can be easily changed by the web administrator. Then, the Phisher creates a fake information input website, and send out e-mails containing a link to this fake website to lure e-mail recipients into visiting his fake website.Most Phishers create imitations of well known enterprises websites to lure users into using their fake websites. Even so, a user can easily notice that the URL of the website they’re entering has no relation to the intended enterprise. Hence, Phishers may use different methods to impersonate enterprises and other people. A commonly used method is hiding the URL. This can easily be done with the help of JavaScript.Another way is to exploit the loopholes in an internet browser, for instance, displaying a fake URL in the browser’s address bar. The security loophole causing the address bar of a browser to display a fake URL is a commonly used trick and has often been used in the past. For example, an e-mail in HTML format may hold the URL of a website of a well-known enterprise, but in reality, the link connects to a fake website.The key to successfully use a URL similar to that of the intended website is to trick the visual senses. For example, the sender’s address could be disguised as that of Nikkei BP, and the link set to http://www.nikeibp.co.jp/ which has one k less than the correct URL which is http://www.nikkeibp.co.jp/. The two URLs look very similar, and the difference barely noticeable. Hence people are easily tricked into clicking the link.Besides the above, there are many more scams that exploit the trickery of visual senses. Therefore, you should not easily trust the given sender’s name and a website’s appearance. Never click on unfamiliar and suspicious URLs on a webpage. Also, never enter personal information into a website without careful scrutiny.3. ConclusionsBusiness strategy is the most effective form of defense and also the easiest to carry out. Therefore, they should be the first line of defense, and not last. First, determine if instant messaging is essential in the business; then weigh its pros and cons. Rules and norms must be set on user ends if it is decided that the business cannot do without instant messaging functionality. The end server should be able to support functions like centralized logging and encryption. If not, then strict rules must be drawn, and carried out by the users. Especially, business discussions must not be done over an instant messenger.The paper categorized hacking tricks into three categories: (1) Trojan programs that share files via instant messenger. (2) Phishing (3) Fake Websites. Hacking tricks when successfully carried out could cause considerable loss and damage to users. The first category of hacking tricks can be divided into three types: (1) Hijacking and Impersonation; (2) Denial of Service; (3) Information Disclosure.Acknowledgement:This work was supported by the National Science Council, Taiwan, under contract No. NSC 95-2221-E-029-024.References[1] B. Schneier, “The trojan horse race,”Communications of ACM, Vol. 42, 1999, pp.128.[2] C. L. Schuba, “Analysis of a denial of serviceattack on TCP,” IEEE Security and PrivacyConference, 1997, pp. 208-223.[3] E. Schultz, “Phishing is becoming moresophisticated,” Computer and Security, Vol.24(3), 2005, pp. 184-185.[4]G. Miklau, D. Suciu, “A formal analysis ofinformation disclosure in data exchange,”International Conference on Management ofData, 2004, pp. 575-586.[5]J. Hoyle, “'Phishing' for trouble,” Journal ofthe American Detal Association, Vol. 134(9),2003, pp. 1182-1182.[6]J. Scambray, S. McClure, G. Kurtz, Hackingexposed: network security secrets and solutions,McGraw-Hill, 2001.[7]T. Tsuji and A. Shimizu, “An impersonationattack on one-time password authenticationprotocol OSPA,” to appear in IEICE Trans.Commun, Vol. E86-B, No.7, 2003.[8]Anti-Phishing Working Group,.[9]/region/tw/enterprise/article/icq_threat.html.有关网络环境安全的黑客技术摘要：现在人们往往通过互联网处理事务。
毕业设计论文外文文献翻译
xxxx大学xxx学院毕业设计（论文）外文文献翻译系部xxxx专业xxxx学生姓名xxxx 学号xxxx指导教师xxxx 职称xxxx2013年3 月Introducing the Spring FrameworkThe Spring Framework: a popular open source application framework that addresses many of the issues outlined in this book. This chapter will introduce the basic ideas of Spring and dis-cuss the central “bean factory” lightweight Inversion-of-Control (IoC) container in detail.Spring makes it particularly easy to implement lightweight, yet extensible, J2EE archi-tectures. It provides an out-of-the-box implementation of the fundamental architectural building blocks we recommend. Spring provides a consistent way of structuring your applications, and provides numerous middle tier features that can make J2EE development significantly easier and more flexible than in traditional approaches.The basic motivations for Spring are:To address areas not well served by other frameworks. There are numerous good solutions to specific areas of J2EE infrastructure: web frameworks, persistence solutions, remoting tools, and so on. However, integrating these tools into a comprehensive architecture can involve significant effort, and can become a burden. Spring aims to provide an end-to-end solution, integrating spe-cialized frameworks into a coherent overall infrastructure. Spring also addresses some areas that other frameworks don’t. For example, few frameworks address generic transaction management, data access object implementation, and gluing all those things together into an application, while still allowing for best-of-breed choice in each area. Hence we term Spring an application framework, rather than a web framework, IoC or AOP framework, or even middle tier framework.To allow for easy adoption. A framework should be cleanly layered, allowing the use of indi-vidual features without imposing a whole worldview on the application. Many Spring features, such as the JDBC abstraction layer or Hibernate integration, can be used in a library style or as part of the Spring end-to-end solution.To deliver ease of use. As we’ve noted, J2EE out of the box is relatively hard to use to solve many common problems. A good infrastructure framework should make simple tasks simple to achieve, without forcing tradeoffs for future complex requirements (like distributed transactions) on the application developer. It should allow developers to leverage J2EE services such as JTA where appropriate, but to avoid dependence on them in cases when they are unnecessarily complex.To make it easier to apply best practices. Spring aims to reduce the cost of adhering to best practices such as programming to interfaces, rather than classes, almost to zero. However, it leaves the choice of architectural style to the developer.Non-invasiveness. Application objects should have minimal dependence on the framework. If leveraging a specific Spring feature, an object should depend only on that particular feature, whether by implementing a callback interface or using the framework as a class library. IoC and AOP are the key enabling technologies for avoiding framework dependence.Consistent configuration. A good infrastructure framework should keep application configuration flexible and consistent, avoiding the need for custom singletons and factories. A single style should be applicable to all configuration needs, from the middle tier to web controllers.Ease of testing. Testing either whole applications or individual application classes in unit tests should be as easy as possible. Replacing resources or application objects with mock objects should be straightforward.To allow for extensibility. Because Spring is itself based on interfaces, rather than classes, it is easy to extend or customize it. Many Spring components use strategy interfaces, allowing easy customization.A Layered Application FrameworkChapter 6 introduced the Spring Framework as a lightweight container, competing with IoC containers such as PicoContainer. While the Spring lightweight container for JavaBeans is a core concept, this is just the foundation for a solution for all middleware layers.Basic Building Blockspring is a full-featured application framework that can be leveraged at many levels. It consists of multi-ple sub-frameworks that are fairly independent but still integrate closely into a one-stop shop, if desired. The key areas are:Bean factory. The Spring lightweight IoC container, capable of configuring and wiring up Java-Beans and most plain Java objects, removing the need for custom singletons and ad hoc configura-tion. Various out-of-the-box implementations include an XML-based bean factory. The lightweight IoC container and its Dependency Injection capabilities will be the main focus of this chapter.Application context. A Spring application context extends the bean factory concept by adding support for message sources and resource loading, and providing hooks into existing environ-ments. Various out-of-the-box implementations include standalone application contexts and an XML-based web application context.AOP framework. The Spring AOP framework provides AOP support for method interception on any class managed by a Spring lightweight container.It supports easy proxying of beans in a bean factory, seamlessly weaving in interceptors and other advice at runtime. Chapter 8 dis-cusses the Spring AOP framework in detail. The main use of the Spring AOP framework is to provide declarative enterprise services for POJOs.Auto-proxying. Spring provides a higher level of abstraction over the AOP framework and low-level services, which offers similar ease-of-use to .NET within a J2EE context. In particular, the provision of declarative enterprise services can be driven by source-level metadata.Transaction management. Spring provides a generic transaction management infrastructure, with pluggable transaction strategies (such as JTA and JDBC) and various means for demarcat-ing transactions in applications. Chapter 9 discusses its rationale and the power and flexibility that it offers.DAO abstraction. Spring defines a set of generic data access exceptions that can be used for cre-ating generic DAO interfaces that throw meaningful exceptions independent of the underlying persistence mechanism. Chapter 10 illustrates the Spring support for DAOs in more detail, examining JDBC, JDO, and Hibernate as implementation strategies.JDBC support. Spring offers two levels of JDBC abstraction that significantly ease the effort of writing JDBC-based DAOs: the org.springframework.jdbc.core package (a template/callback approach) and the org.springframework.jdbc.object package (modeling RDBMS operations as reusable objects). Using the Spring JDBC packages can deliver much greater pro-ductivity and eliminate the potential for common errors such as leaked connections, compared with direct use of JDBC. The Spring JDBC abstraction integrates with the transaction and DAO abstractions.Integration with O/R mapping tools. Spring provides support classesfor O/R Mapping tools like Hibernate, JDO, and iBATIS Database Layer to simplify resource setup, acquisition, and release, and to integrate with the overall transaction and DAO abstractions. These integration packages allow applications to dispense with custom ThreadLocal sessions and native transac-tion handling, regardless of the underlying O/R mapping approach they work with.Web MVC framework. Spring provides a clean implementation of web MVC, consistent with the JavaBean configuration approach. The Spring web framework enables web controllers to be configured within an IoC container, eliminating the need to write any custom code to access business layer services. It provides a generic DispatcherServlet and out-of-the-box controller classes for command and form handling. Request-to-controller mapping, view resolution, locale resolution and other important services are all pluggable, making the framework highly extensi-ble. The web framework is designed to work not only with JSP, but with any view technology, such as Velocity—without the need for additional bridges. Chapter 13 discusses web tier design and the Spring web MVC framework in detail.Remoting support. Spring provides a thin abstraction layer for accessing remote services without hard-coded lookups, and for exposing Spring-managed application beans as remote services. Out-of-the-box support is inc luded for RMI, Caucho’s Hessian and Burlap web service protocols, and WSDL Web Services via JAX-RPC. Chapter 11 discusses lightweight remoting.While Spring addresses areas as diverse as transaction management and web MVC, it uses a consistent approach everywhere. Once you have learned the basic configuration style, you will be able to apply it in many areas. Resources, middle tier objects, and web components are all set up using the same bean configuration mechanism. You can combine your entireconfiguration in one single bean definition file or split it by application modules or layers; the choice is up to you as the application developer. There is no need for diverse configuration files in a variety of formats, spread out across the application.Spring on J2EEAlthough many parts of Spring can be used in any kind of Java environment, it is primarily a J2EE application framework. For example, there are convenience classes for linking JNDI resources into a bean factory, such as JDBC DataSources and EJBs, and integration with JTA for distributed transaction management. In most cases, application objects do not need to work with J2EE APIs directly, improving reusability and meaning that there is no need to write verbose, hard-to-test, JNDI lookups.Thus Spring allows application code to seamlessly integrate into a J2EE environment without being unnecessarily tied to it. You can build upon J2EE services where it makes sense for your application, and choose lighter-weight solutions if there are no complex requirements. For example, you need to use JTA as transaction strategy only if you face distributed transaction requirements. For a single database, there are alternative strategies that do not depend on a J2EE container. Switching between those transac-tion strategies is merely a matter of configuration; Spring’s consistent abstraction avoids any need to change application code.Spring offers support for accessing EJBs. This is an important feature (and relevant even in a book on “J2EE without EJB”) because the u se of dynamic proxies as codeless client-side business delegates means that Spring can make using a local stateless session EJB an implementation-level, rather than a fundamen-tal architectural, choice.Thus if you want to use EJB, you can within a consistent architecture; however, you do not need to make EJB the cornerstone of your architecture. This Spring feature can make devel-oping EJB applications significantly faster, because there is no need to write custom code in service loca-tors or business delegates. Testing EJB client code is also much easier, because it only depends on the EJB’s Business Methods interface (which is not EJB-specific), not on JNDI or the EJB API.Spring also provides support for implementing EJBs, in the form of convenience superclasses for EJB implementation classes, which load a Spring lightweight container based on an environment variable specified in the ejb-jar.xml deployment descriptor. This is a powerful and convenient way of imple-menting SLSBs or MDBs that are facades for fine-grained POJOs: a best practice if you do choose to implement an EJB application. Using this Spring feature does not conflict with EJB in any way—it merely simplifies following good practice.Introducing the Spring FrameworkThe main aim of Spring is to make J2EE easier to use and promote good programming practice. It does not reinvent the wheel; thus you’ll find no logging packages in Spring, no connection pools, no distributed transaction coordinator. All these features are provided by other open source projects—such as Jakarta Commons Logging (which Spring uses for all its log output), Jakarta Commons DBCP (which can be used as local DataSource), and ObjectWeb JOTM (which can be used as transaction manager)—or by your J2EE application server. For the same reason, Spring doesn’t provide an O/R mapping layer: There are good solutions for this problem area, such as Hibernate and JDO.Spring does aim to make existing technologies easier to use. For example, although Spring is not in the business of low-level transactioncoordination, it does provide an abstraction layer over JTA or any other transaction strategy. Spring is also popular as middle tier infrastructure for Hibernate, because it provides solutions to many common issues like SessionFactory setup, ThreadLocal sessions, and exception handling. With the Spring HibernateTemplate class, implementation methods of Hibernate DAOs can be reduced to one-liners while properly participating in transactions.The Spring Framework does not aim to replace J2EE middle tier services as a whole. It is an application framework that makes accessing low-level J2EE container ser-vices easier. Furthermore, it offers lightweight alternatives for certain J2EE services in some scenarios, such as a JDBC-based transaction strategy instead of JTA when just working with a single database. Essentially, Spring enables you to write appli-cations that scale down as well as up.Spring for Web ApplicationsA typical usage of Spring in a J2EE environment is to serve as backbone for the logical middle tier of a J2EE web application. Spring provides a web application context concept, a powerful lightweight IoC container that seamlessly adapts to a web environment: It can be accessed from any kind of web tier, whether Struts, WebWork, Tapestry, JSF, Spring web MVC, or a custom solution.The following code shows a typical example of such a web application context. In a typical Spring web app, an applicationContext.xml file will reside in the WEB-INF directory, containing bean defini-tions according to the “spring-beans” DTD. In such a bean definition XML file, business objects and resources are defined, for example, a “myDataSource” bean, a “myInventoryManager” bean, and a “myProductManager” bean. Spring takes care of their configuration, their wiring up, and their lifecycle.<beans><bean id=”myDataSource” class=”org.springframework.jdbc. datasource.DriverManagerDataSource”><property name=”driverClassName”> <value>com.mysql.jdbc.Driver</value></property> <property name=”url”><value>jdbc:mysql:myds</value></property></bean><bean id=”myInventoryManager” class=”ebusiness.DefaultInventoryManager”> <property name=”dataSource”><ref bean=”myDataSource”/> </property></bean><bean id=”myProductManager” class=”ebusiness.DefaultProductManage r”><property name=”inventoryManager”><ref bean=”myInventoryManager”/> </property><property name=”retrieveCurrentStock”> <value>true</value></property></bean></beans>By default, all such beans have “singleton” scope: one instance per context. The “myInventoryManager” bean will automatically be wired up with the defined DataSource, while “myProductManager” will in turn receive a reference to the “myInventoryManager” bean. Those objects (traditionally called “beans” in Spring terminology) need to expos e only the corresponding bean properties or constructor arguments (as you’ll see later in this chapter); they do not have to perform any custom lookups.A root web application context will be loaded by a ContextLoaderListener that is defined in web.xml as follows:<web-app><listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class></listener>...</web-app>After initialization of the web app, the root web application context will be available as a ServletContext attribute to the whole web application, in the usual manner. It can be retrieved from there easily via fetching the corresponding attribute, or via a convenience method in org.springframework.web. context.support.WebApplicationContextUtils. This means that the application context will be available in any web resource with access to the ServletContext, like a Servlet, Filter, JSP, or Struts Action, as follows:WebApplicationContext wac = WebApplicationContextUtils.getWebApplicationContext(servletContext);The Spring web MVC framework allows web controllers to be defined as JavaBeans in child application contexts, one per dispatcher servlet. Such controllers can express dependencies on beans in the root application context via simple bean references. Therefore, typical Spring web MVC applications never need to perform a manual lookup of an application context or bean factory, or do any other form of lookup.Neither do other client objects that are managed by an application context themselves: They can receive collaborating objects as bean references.The Core Bean FactoryIn the previous section, we have seen a typical usage of the Spring IoC container in a web environment: The provided convenience classes allow for seamless integration without having to worry about low-level container details. Nevertheless, it does help to look at the inner workings to understand how Spring manages the container. Therefore, we will now look at the Spring bean container in more detail, starting at the lowest building block: the bean factory. Later, we’ll continue with resource setup and details on the application context concept.One of the main incentives for a lightweight container is to dispense with the multitude of custom facto-ries and singletons often found in J2EE applications. The Spring bean factory provides one consistent way to set up any number of application objects, whether coarse-grained components or fine-grained busi-ness objects. Applying reflection and Dependency Injection, the bean factory can host components that do not need to be aware of Spring at all. Hence we call Spring a non-invasive application framework.Fundamental InterfacesThe fundamental lightweight container interface is org.springframework.beans.factory.Bean Factory. This is a simple interface, which is easy to implement directly in the unlikely case that none of the implementations provided with Spring suffices. The BeanFactory interface offers two getBean() methods for looking up bean instances by String name, with the option to check for a required type (and throw an exception if there is a type mismatch).public interface BeanFactory {Object getBean(String name) throws BeansException;Object getBean(String name, Class requiredType) throws BeansException;boolean containsBean(String name);boolean isSingleton(String name) throws NoSuchBeanDefinitionException;String[] getAliases(String name) throws NoSuchBeanDefinitionException;}The isSingleton() method allows calling code to check whether the specified name represents a sin-gleton or prototype bean definition. In the case of a singleton bean, all calls to the getBean() method will return the same object instance. In the case of a prototype bean, each call to getBean() returns an inde-pendent object instance, configured identically.The getAliases() method will return alias names defined for the given bean name, if any. This mecha-nism is used to provide more descriptive alternative names for beans than are permitted in certain bean factory storage representations, such as XML id attributes.The methods in most BeanFactory implementations are aware of a hierarchy that the implementation may be part of. If a bean is not foundin the current factory, the parent factory will be asked, up until the root factory. From the point of view of a caller, all factories in such a hierarchy will appear to be merged into one. Bean definitions in ancestor contexts are visible to descendant contexts, but not the reverse.All exceptions thrown by the BeanFactory interface and sub-interfaces extend org.springframework. beans.BeansException, and are unchecked. This reflects the fact that low-level configuration prob-lems are not usually recoverable: Hence, application developers can choose to write code to recover from such failures if they wish to, but should not be forced to write code in the majority of cases where config-uration failure is fatal.Most implementations of the BeanFactory interface do not merely provide a registry of objects by name; they provide rich support for configuring those objects using IoC. For example, they manage dependen-cies between managed objects, as well as simple properties. In the next section, we’ll look at how such configuration can be expressed in a simple and intuitive XML structure.The sub-interface org.springframework.beans.factory.ListableBeanFactory supports listing beans in a factory. It provides methods to retrieve the number of beans defined, the names of all beans, and the names of beans that are instances of a given type:public interface ListableBeanFactory extends BeanFactory {int getBeanDefinitionCount();String[] getBeanDefinitionNames();String[] getBeanDefinitionNames(Class type);boolean containsBeanDefinition(String name);Map getBeansOfType(Class type, boolean includePrototypes,boolean includeFactoryBeans) throws BeansException}The ability to obtain such information about the objects managed by a ListableBeanFactory can be used to implement objects that work with a set of other objects known only at runtime.In contrast to the BeanFactory interface, the methods in ListableBeanFactory apply to the current factory instance and do not take account of a hierarchy that the factory may be part of. The org.spring framework.beans.factory.BeanFactoryUtils class provides analogous methods that traverse an entire factory hierarchy.There are various ways to leverage a Spring bean factory, ranging from simple bean configuration to J2EE resource integration and AOP proxy generation. The bean factory is the central, consistent way of setting up any kind of application objects in Spring, whether DAOs, business objects, or web controllers. Note that application objects seldom need to work with the BeanFactory interface directly, but are usu-ally configured and wired by a factory without the need for any Spring-specific code.For standalone usage, the Spring distribution provides a tiny spring-core.jar file that can be embed-ded in any kind of application. Its only third-party dependency beyond J2SE 1.3 (plus JAXP for XML parsing) is the Jakarta Commons Logging API.The bean factory is the core of Spring and the foundation for many other services that the framework offers. Nevertheless, the bean factory can easily be used stan-dalone if no other Spring services are required.Derivative：networkSpring 框架简介Spring框架：这是一个流行的开源应用框架，它可以解决很多问题。
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外文原文(一)Savigny and his Anglo-American Disciple s*M. H. HoeflichFriedrich Carl von Savigny, nobleman, law reformer, champion of the revived German professoriate, and founder of the Historical School of jurisprudence, not only helped to revolutionize the study of law and legal institutions in Germany and in other civil law countries, but also exercised a profound influence on many of the most creative jurists and legal scholars in England and the United States. Nevertheless, tracing the influence of an individual is always a difficult task. It is especially difficult as regards Savigny and the approach to law and legal sources propounded by the Historical School. This difficulty arises, in part, because Savigny was not alone in adopting this approach. Hugo, for instance, espoused quite similar ideas in Germany; George Long echoed many of these concepts in England during the 1850s, and, of course, Sir Henry Sumner Maine also espoused many of these same concepts central to historical jurisprudence in England in the 1860s and 1870s. Thus, when one looks at the doctrinal writings of British and American jurists and legal scholars in the period before 1875, it is often impossible to say with any certainty that a particular idea which sounds very much the sort of thing that might, indeed, have been derived from Savigny's works, was, in fact, so derived. It is possible, nevertheless, to trace much of the influence of Savigny and his legal writings in the United States and in Great Britain during this period with some certainty because so great was his fame and so great was the respect accorded to his published work that explicit references to him and to his work abound in the doctrinal writing of this period, as well as in actual law cases in the courts. Thus, Max Gutzwiller, in his classic study Der einfluss Savignys auf die Entwicklung des International privatrechts, was able to show how Savigny's ideas on conflict of laws influenced such English and American scholars as Story, Phillimore, Burge, and Dicey. Similarly, Andreas Schwarz, in his "Einflusse Deutscher Zivilistik im Auslande," briefly sketched Savigny's influence upon John Austin, Frederick Pollock, and James Bryce. In this article I wish to examine Savigny's influence over a broader spectrum and to draw a picture of his general fame and reputation both in Britain and in the United States as the leading Romanist, legal historian, and German legal academic of his day. The picture of this Anglo-American respect accorded to Savigny and the historical school of jurisprudence which emerges from these sources is fascinating. It sheds light not only upon Savigny’s trans-channel, trans-Atlantic fame, but also upon the extraordinarily*M.H.Hoeflich, Savigny and his Anglo-American Disciples, American Journal of Comparative Law, vol.37, No.1, 1989.cosmopolitan outlook of many of the leading American and English jurists of the time. Of course, when one sets out to trace the influence of a particular individual and his work, it is necessary to demonstrate, if possible, precisely how knowledge of the man and his work was transmitted. In the case of Savigny and his work on Roman law and ideas of historical jurisprudence, there were three principal modes of transmission. First, there was the direct influence he exercised through his contacts with American lawyers and scholars. Second, there was the influence he exercised through his books. Third, there was the influence he exerted indirectly through intermediate scholars and their works. Let us examine each mode separately.I.INFLUENCE OF THE TRANSLATED WORKSWhile American and British interest in German legal scholarship was high in the antebellum period, the number of American and English jurists who could read German fluently was relatively low. Even those who borrowed from the Germans, for instance, Joseph Story, most often had to depend upon translations. It is thus quite important that Savigny’s works were amongst the most frequently translated into English, both in the United States and in Great Britain. His most influential early work, the Vom Beruf unserer Zeitfur Rechtsgeschichte und Gestzgebung, was translated into English by Abraham Hayward and published in London in 1831. Two years earlier the first volume of his History of Roman Law in the Middle Ages was translated by Cathcart and published in Edinburgh. In 1830, as well, a French translation was published at Paris. Sir Erskine Perry's translation of Savigny's Treatise on Possession was published in London in 1848. This was followed by Archibald Brown's epitome of the treatise on possession in 1872 and Rattigan's translation of the second volume of the System as Jural Relations or the Law of Persons in 1884. Guthrie published a translation of the seventh volume of the System as Private International Law at Edinburgh in 1869. Indeed, two English translations were even published in the far flung corners of the British Raj. A translation of the first volume of the System was published by William Holloway at Madras in 1867 and the volume on possession was translated by Kelleher and published at Calcutta in 1888. Thus, the determined English-speaking scholar had ample access to Savigny's works throughout the nineteenth century.Equally important for the dissemination of Savigny's ideas were those books and articles published in English that explained and analyzed his works. A number of these must have played an important role in this process. One of the earliest of these is John Reddie's Historical Notices of the Roman law and of the Progress of its Study in Germany, published at Edinburgh in 1826. Reddie was a noted Scots jurist and held the Gottingen J.U.D. The book, significantly, is dedicated to Gustav Hugo. It is of that genre known as an external history of Roman law-not so much a history of substantive Roman legal doctrine but rather a historyof Roman legal institutions and of the study of Roman law from antiquity through the nineteenth century. It is very much a polemic for the study of Roman law and for the Historical School. It imparts to the reader the excitement of Savigny and his followers about the study of law historically and it is clear that no reader of the work could possibly be left unmoved. It is, in short, the first work of public relations in English on behalf of Savigny and his ideas.Having mentioned Reddie's promotion of Savigny and the Historical School, it is important to understand the level of excitement with which things Roman and especially Roman law were greeted during this period. Many of the finest American jurists were attracted-to use Peter Stein's term-to Roman and Civil law, but attracted in a way that, at times, seems to have been more enthusiastic than intellectual. Similarly, Roman and Civil law excited much interest in Great Britain, as illustrated by the distinctly Roman influence to be found in the work of John Austin. The attraction of Roman and Civil law can be illustrated and best understood, perhaps, in the context of the publicity and excitement in the English-speaking world surrounding the discovery of the only complete manuscript of the classical Roman jurist Gaius' Institutes in Italy in 1816 by the ancient historian and German consul at Rome, B.G. Niebuhr. Niebuhr, the greatest ancient historian of his time, turned to Savigny for help with the Gaius manuscript (indeed, it was Savigny who recognized the manuscript for what it was) and, almost immediately, the books and journals-not just law journals by any means-were filled with accounts of the discovery, its importance to legal historical studies, and, of course, what it said. For instance, the second volume of the American Jurist contains a long article on the civil law by the scholarly Boston lawyer and classicist, John Pickering. The first quarter of the article is a gushing account of the discovery and first publication of the Gaius manuscript and a paean to Niebuhr and Savigny for their role in this. Similarly, in an article published in the London Law Magazine in 1829 on the civil law, the author contemptuously refers to a certain professor who continued to tell his students that the text of Gaius' Institutes was lost for all time. What could better show his ignorance of all things legal and literary than to be unaware of Niebuhr's great discovery?Another example of this reaction to the discovery of the Gaius palimpsest is to be found in David Irving's Introduction to the Study of the Civil Law. This volume is also more a history of Roman legal scholarship and sources than a study of substantive Roman law. Its pages are filled with references to Savigny's Geschichte and its approach clearly reflects the influence of the Historical School. Indeed, Irving speaks of Savigny's work as "one of the most remarkable productions of the age." He must have been truly impressed with German scholarship and must also have been able to convince the Faculty of Advocates, forwhom he was librarian, of the worth of German scholarship, for in 1820 the Faculty sent him to Gottingen so that he might study their law libraries. Irving devotes several pages of his elementary textbook on Roman law to the praise of the "remarkable" discovery of the Gaius palimpsest. He traces the discovery of the text by Niebuhr and Savigny in language that would have befitted an adventure tale. He elaborates on the various labors required to produce a new edition of the text and was particularly impressed by the use of a then new chemical process to make the under text of the palimpsest visible. He speaks of the reception of the new text as being greeted with "ardor and exultation" strong words for those who spend their lives amidst the "musty tomes" of the Roman law.This excitement over the Verona Gaius is really rather strange. Much of the substance of the Gaius text was already known to legal historians and civil lawyers from its incorporation into Justinian's Institutes and so, from a substantive legal perspective, the find was not crucial. The Gaius did provide new information on Roman procedural rules and it did also provide additional information for those scholars attempting to reconstruct pre-Justinianic Roman law. Nevertheless, these contributions alone seem hardly able to justify the excitement the discovery caused. Instead, I think that the Verona Gaius discovery simply hit a chord in the literary and legal community much the same as did the discovery of the Rosetta Stone or of Schliemann’s Troy. Here was a monument of a great civilization brought newly to light and able to be read for the first time in millenia. And just as the Rosetta Stone helped to establish the modern discipline of Egyptology and Schliemann's discoveries assured the development of classical archaeology as a modern academic discipline, the discovery of the Verona Gaius added to the attraction Roman law held for scholars and for lawyers, even amongst those who were not Romanists by profession. Ancillary to this, the discovery and publication of the Gaius manuscript also added to the fame of the two principals involved in the discovery, Niebuhr and Savigny. What this meant in the English-speaking world is that even those who could not or did not wish to read Savigny's technical works knew of him as one of the discoverers of the Gaius text. This fame itself may well have helped in spreading Savigny's legal and philosophical ideas, for, I would suggest, the Gaius "connection" may well have disposed people to read other of Savigny's writings, unconnected to the Gaius, because they were already familiar with his name.Another example of an English-speaking promoter of Savigny is Luther Stearns Cushing, a noted Boston lawyer who lectured on Roman law at the Harvard Law School in 1848-49 and again in 1851- 1852.Cushing published his lectures at Boston in 1854 under the title An Introduction to the Study of Roman Law. He devoted a full chapter to a description of the historical school and to the controversy betweenSavigny and Thibaut over codification. While Cushing attempted to portray fairly the arguments of both sides, he left no doubt as to his preference for Savigny's approach:The labors of the historical school have established an entirely new and distinct era in the study of the Roman jurisprudence; and though these writers cannot be said to have thrown their predecessors into the shade, it seems to be generally admitted, that almost every branch of the Roman law has received some important modification at their hands, and that a knowledge of their writings, to some extent, at least, is essentially necessary to its acquisition.译文(一)萨维尼和他的英美信徒们*M·H·豪弗里奇弗雷德里奇·卡尔·冯·萨维尼出身贵族，是一位出色的法律改革家，也是一位倡导重建德国教授协会的拥护者，还是历史法学派的创建人之一。
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WebsiteFrom Wikipedia, the free encyclopediaA website is a collection of related web pages, images, videos or other digital assets that are addressed relative to a common Uniform Resource Locator (URL), often consisting of only the domain name, or the IP address, and the root path in an Internet Protocol-based network. A web site is hosted on at least one web server, accessible via a network such as the Internet or a private local area network.A web page is a document, typically written in plain text interspersed with formatting instructions of Hypertext Markup Language (HTML, XHTML).A web page may incorporate elements from other websites with suitable markup anchors.Web pages are accessed and transported with the Hypertext Transfer Protocol (HTTP), which may optionally employ encryption (HTTP Secure, HTTPS) to provide security and privacy for the user of the web page content. The user's application, often a web browser, renders the page content according to its HTML markup instructions onto a display terminal.All publicly accessible websites collectively constitute the World Wide Web.the pages of a website can usually be accessed from a simple Uniform Resource Locator called the homepage. The URLs of the pages organize them into a hierarchy, although hyperlinking between them conveys the reader's perceived site structure and guides the reader's navigation of the site.Some websites require a subscription to access some or all of their content. Examples of subscription sites include many business sites, parts of many news sites, academic journal sites, gaming sites, message boards, web-based e-mail, social networking websites, and sites providing real-time stock market data.1.HistoryThe World Wide Web (WWW) was created in 1989 by CERN physicist Tim Berners-Lee.On 30 April 1993, CERN announced that the World Wide Web would be free to use for anyone.Before the introduction of HTML and HTTP, other protocols such as filetransfer protocol and the gopher protocol were used to retrieve individual files from a server. These protocols offer a simple directory structure which the user navigates and chooses files to download. Documents were most often presented as plain text files without formatting or were encoded in word processor formats.2.OverviewOrganized by function, a website may be（1）a personal website（2）a commercial website（3）a government website（4）a non-profit organization websiteIt could be the work of an individual, a business or other organization, and is typically dedicated to some particular topic or purpose. Any website can contain a hyperlink to any other website, so the distinction between individual sites, as perceived by the user, may sometimes be blurred.Websites are written in, or dynamically converted to HTML (Hyper Text Markup Language) and are accessed using a software interface classified as a user agent. Web pages can be viewed or otherwise accessed from a range of computer-based and Internet-enabled devices of various sizes, including desktop computers, laptops, PDAs and cell phones.A website is hosted on a computer system known as a web server, also called an HTTP server, and these terms can also refer to the software that runs on these systems and that retrieves and delivers the web pages in response to requests from the website users. Apache is the most commonly used web server software (according to Netcraft statistics) and Microsoft's Internet Information Server (IIS) is also commonly used.3. Static websiteA static website is one that has web pages stored on the server in the format that is sent to a client web browser. It is primarily coded in Hypertext Markup Language (HTML).Simple forms or marketing examples of websites, such as classic website, a five-page website or a brochure website are often static websites, because they present pre-defined, static information to the user. This may includeinformation about a company and its products and services via text, photos, animations, audio/video and interactive menus and navigation.This type of website usually displays the same information to all visitors. Similar to handing out a printed brochure to customers or clients, a static website will generally provide consistent, standard information for an extended period of time. Although the website owner may make updates periodically, it is a manual process to edit the text, photos and other content and may require basic website design skills and software.In summary, visitors are not able to control what information they receive via a static website, and must instead settle for whatever content the website owner has decided to offer at that time.They are edited using four broad categories of software:(1) Text editors, such as Notepad or TextEdit, where content and HTML markup are manipulated directly within the editor program(2) Wysiwyg offline editors, such as Microsoft FrontPage and Adobe Dreamweaver (previously Macromedia Dreamweaver), with which the site is edited using a GUI interface and the final HTML markup is generated automatically by the editor software(3) Wysiwyg online editors which create media rich online presentation like web pages, widgets, intro, blogs, and other documents.(4) Template-based editors, such as Rapidweaver and iWeb, which allow users to quickly create and upload web pages to a web server without detailed HTML knowledge, as they pick a suitable template from a palette and add pictures and text to it in a desktop publishing fashion without direct manipulation of HTML code.4. Dynamic websiteA dynamic website is one that changes or customizes itself frequently and automatically, based on certain criteria.Dynamic websites can have two types of dynamic activity: Code and Content. Dynamic code is invisible or behind the scenes and dynamic content is visible or fully displayed.(1) Dynamic codeThe first type is a web page with dynamic code. The code is constructed dynamically on the fly using active programming language instead of plain,static HTML.A website with dynamic code refers to its construction or how it is built, and more specifically refers to the code used to create a single web page. A dynamic web page is generated on the fly by piecing together certain blocks of code, procedures or routines. A dynamically-generated web page would call various bits of information from a database and put them together in a pre-defined format to present the reader with a coherent page. It interacts with users in a variety of ways including by reading cookies recognizing users' previous history, session variables, server side variables etc., or by using direct interaction (form elements, mouse overs, etc.). A site can display the current state of a dialogue between users, monitor a changing situation, or provide information in some way personalized to the requirements of the individual user.(2) Dynamic contentThe second type is a website with dynamic content displayed in plain view. Variable content is displayed dynamically on the fly based on certain criteria, usually by retrieving content stored in a database.A website with dynamic content refers to how its messages, text, images and other information are displayed on the web page and more specifically how its content changes at any given moment. The web page content varies based on certain criteria, either pre-defined rules or variable user input. For example, a website with a database of news articles can use a pre-defined rule which tells it to display all news articles for today's date. This type of dynamic website will automatically show the most current news articles on any given date. Another example of dynamic content is when a retail website with a database of media products allows a user to input a search request for the keyword Beatles. In response, the content of the web page will spontaneously change the way it looked before, and will then display a list of Beatles products like CD's, DVD's and books.5. Software systemsThere is a wide range of software systems, such as Java Server Pages (JSP), the PHP and Perl programming languages, Active Server Pages (ASP), Yuma and ColdFusion (CFML) that are available to generate dynamic web systems and dynamic sites. Sites may also include content that is retrievedfrom one or more databases or by using XML-based technologies such as RSS.Static content may also be dynamically generated either periodically, or if certain conditions for regeneration occur (cached) in order to avoid the performance loss of initiating the dynamic engine on a per-user or per-connection basis.Plugins are available to expand the features and abilities of web browsers, which use them to show active content, such as Microsoft Silverlight, Adobe Flash, Adobe Shockwave or applets written in Java. Dynamic HTML also provides for user interactivity and real time element updating within web pages (ie pages don't have to be loaded or reloaded to effect any changes), mainly using the Document Object Model (DOM) and JavaScript, support which is built-in to most modern web browsers.Turning a website into an income source is a common practice for web developers and website owners. There are several methods for creating a website business which fall into two broad categories, as defined below.(1) Content-based siteSome websites derive revenue by selling advertising space on the site (see Contextual advertising).(2) Product- or service-based sitesSome websites derive revenue by offering products or services for sale. In the case of e-commerce websites, the products or services may be purchased at the website itself, by entering credit card or other payment information into a payment form on the site. While most business websites serve as a shop window for existing brick and mortar businesses, it is increasingly the case that some websites are businesses in their own right; that is, the products they offer are only available for purchase on the web.Websites occasionally derive income from a combination of these two practices. For example, a website such as an online auctions website may charge the users of its auction service to list an auction, but also display third-party advertisements on the site, from which it derives further income.网站文章来自维基百科，自由的百科全书网站是一组相关的网页，图片，视频或其他数字资产的集合，是针对相对的一个共同的统一资源定位符（URL），这个定位器往往由域名，或组成的IP地址在以网络为基础的互联网协议上的根路径构成。
毕业设计外文翻译英文翻译英文原稿
Harmonic source identification and current separationin distribution systemsYong Zhao a，b，Jianhua Li a，Daozhi Xia a,*a Department of Electrical Engineering Xi’an Jiaotong University, 28 West Xianning Road, Xi’an, Shaanxi 710049, Chinab Fujian Electric Power Dispatch and Telecommunication Center, 264 Wusi Road, Fuzhou, Fujian, 350003, China AbstractTo effectively diminish harmonic distortions, the locations of harmonic sources have to be identified and their currents have to be separated from that absorbed by conventional linear loads connected to the same CCP. In this paper, based on the intrinsic difference between linear and nonlinear loads in their V –I characteristics and by utilizing a new simplified harmonic source model, a new principle for harmonic source identification and harmonic current separation is proposed. By using this method, not only the existence of harmonic source can be determined, but also the contributions of the harmonic source and the linear loads to harmonic voltage distortion can be distinguished. The detailed procedure based on least squares approximation is given. The effectiveness of the approach is illustrated by test results on a composite load.2004 Elsevier Ltd. All rights reserved.Keywords: Distribution system; Harmonic source identification; Harmonic current separation; Least squares approximation1. IntroductionHarmonic distortion has experienced a continuous increase in distribution systems owing to the growing use of nonlinear loads. Many studies have shown that harmonics may cause serious effects on power systems, communication systems, and various apparatus [1–3]. Harmonic voltages at each point on a distribution network are not only determined by the harmonic currents produced by harmonic sources (nonlinear loads), but also related to all linear loads (harmonic current sinks) as well as the structure and parameters of the network. To effectively evaluate and diminish the harmonic distortion in power systems, the locations of harmonic sources have to be identified and the responsibility of the distortion caused by related individual customers has to be separated.As to harmonic source identification, most commonly the negative harmonic power is considered as an essential evidence of existing harmonic source [4–7]. Several approaches aiming at evaluating the contribution of an individual customer can also be found in the literatures. Schemes based on power factor measurement to penalize the customer’s harmonic currents are discussed in Ref. [8]. However, it would be unfair to use economical penalization if we could not distinguish whether the measured harmonic current is from nonlinear load or from linear load.In fact, the intrinsic difference between linear and nonlinear loads lies in their V –I characteristics. Harmonic currents of a linear load are i n linear proportion to its supplyharmonic voltages of the same order 次, whereas the harmonic currents of a nonlinear load are complex nonlinear functions of its supply fundamental 基波and harmonic voltage components of all orders. To successfully identify and isolate harmonic source in an individual customer or several customers connected at same point in the network, the V –I characteristics should be involved and measurement of voltages and currents under several different supply conditions should be carried out.As the existing approaches based on measurements of voltage and current spectrum or harmonic power at a certain instant cannot reflect the V –I characteristics, they may not provide reliable information about the existence and contribution of harmonic sources, which has been substantiated by theoretical analysis or experimental researches [9,10].In this paper, to approximate the nonlinear characteristics and to facilitate the work in harmonic source identification and harmonic current separation, a new simplified harmonic source model is proposed. Then based on the difference between linear and nonlinear loads in their V –I characteristics, and by utilizing the harmonic source model, a new principle for harmonic source identification and harmonic current separation is presented. By using the method, not only the existence of harmonic source can be determined, but also the contributions of the harmonic sources and the linear loads can be separated. Detailed procedure of harmonic source identification and harmonic current separation based on least squares approximation is presented. Finally, test results on a composite load containing linear and nonlinear loads are given to illustrate the effectiveness of the approach.2. New principle for harmonic source identification and current separationConsider a composite load to be studied in a distribution system, which may represent an individual consumer or a group of customers supplied by a common feeder 支路in the system. To identify whether it contains any harmonic source and to separate the harmonic currents generated by the harmonic sources from that absorbed by conventional linear loads in the measured total harmonic currents of the composite load, the following assumptions are made.(a) The supply voltage and the load currents are both periodical waveforms withperiod T; so that they can be expressed by Fourier series as1()s i n (2)h h h v t ht T πθ∞==+ (1)1()sin(2)h h h i t ht πφ∞==+The fundamental frequency and harmonic components can further be presented bycorresponding phasorshr hi h h hr hi h hV jV V I jI I θφ+=∠+=∠ , 1,2,3,...,h n = (2)(b) During the period of identification, the composite load is stationary, i.e. both its composition and circuit parameters of all individual loads keep unchanged.Under the above assumptions, the relationship between the total harmonic currents of the harmonic sources(denoted by subscript N) in the composite load and the supply voltage, i.e. the V –I characteristics, can be described by the following nonlinear equation ()()()N i t f v t = (3)and can also be represented in terms of phasors as()()122122,,,...,,,,,,...,,Nhr r i nr ni Nh Nhi r inr ni I V V V V V I I V V V V V ⎡⎤=⎢⎥⎣⎦ 2,3,...,h n = (4)Note that in Eq. (4), the initial time (reference time) of the voltage waveform has been properly selected such that the phase angle u1 becomes 0 and 10i V =, 11r V V =in Eq. (2)for simplicity.The V –I characteristics of the linear part (denote by subscript L) of the composite load can be represented by its equivalent harmonic admittance Lh Lh Lh Y G jB =+, and the total harmonic currents absorbed by the linear part can be described as,Lhr LhLh hr Lh Lhi LhLh hi I G B V I I B G V -⎡⎤⎡⎤⎡⎤==⎢⎥⎢⎥⎢⎥⎣⎦⎣⎦⎣⎦2,3,...,h n = (5)From Eqs. (4) and (5), the whole harmonic currents absorbed by the composite load can be expressed as()()122122,,,...,,,,,,...,,hr Lhr Nhr r i nr ni h hi Lhi Nhi r inr ni I I I V V V V V I I I I V V V V V ⎡⎤⎡⎤⎡⎤==-⎢⎥⎢⎥⎢⎥⎣⎦⎣⎦⎣⎦ 2,3,...,h n = (6)As the V –I characteristics of harmonic source are nonlinear, Eq. (6) can neither be directly used for harmonic source identification nor for harmonic current separation. To facilitate the work in practice, simplified methods should be involved. The common practice in harmonic studies is to represent nonlinear loads by means of current harmonic sources or equivalent Norton models [11,12]. However, these models are not of enough precision and new simplified model is needed.From the engineering point of view, the variations of hr V and hi V ; ordinarily fall into^3% bound of the rated bus voltage, while the change of V1 is usually less than ^5%. Within such a range of supply voltages, the following simplified linear relation is used in this paper to approximate the harmonic source characteristics, Eq. (4)112222112322,ho h h r r h i i hnr nr hni ni Nh ho h h r r h i i hnr nr hni ni a a V a V a V a V a V I b b V b V b V b V b V ++++++⎡⎤=⎢⎥++++++⎣⎦2,3,...,h n = (7)这个地方不知道是不是原文写错？23h r r b V 其他的都是2The precision and superiority of this simplified model will be illustrated in Section 4 by test results on several kinds of typical harmonic sources.The total harmonic current (Eq. (6)) then becomes112222112222,2,3,...,Lh Lh hr ho h h r r h i i hnr nr hni ni h Lh Lh hi ho h h r r h i i hnr nr hni ni G B V a a V a V a V a V a V I B G V b b V b V b V b V b V h n-++++++⎡⎤⎡⎤⎡⎤=-⎢⎥⎢⎥⎢⎥++++++⎣⎦⎣⎦⎣⎦= (8)It can be seen from the above equations that the harmonic currents of the harmonic sources (nonlinear loads) and the linear loads differ from each other intrinsically in their V –I characteristics. The harmonic current component drawn by the linear loads is uniquely determined by the harmonic voltage component with same order in the supply voltage. On the other hand, the harmonic current component of the nonlinear loads contains not only a term caused by the same order harmonic voltage but also a constant term and the terms caused by fundamental and harmonic voltages of all other orders. This property will be used for identifying the existence of harmonic source sin composite load.As the test results shown in Section 4 demonstrate that the summation of the constant term and the component related to fundamental frequency voltage in the harmonic current of nonlinear loads is dominant whereas other components are negligible, further approximation for Eq. (7) can be made as follows.Let112'012()()nh h hkr kr hki ki k k h Nhnh h hkr kr hki kik k h a a V a V a V I b b V b V b V =≠=≠⎡⎤+++⎢⎥⎢⎥=⎢⎥⎢⎥+++⎢⎥⎢⎥⎣⎦∑∑ hhr hhi hr Nhhhr hhi hi a a V I b b V ⎡⎤⎡⎤''=⎢⎥⎢⎥⎣⎦⎣⎦hhrhhihr Lh Lh Nh hhrhhi hi a a V I I I b b V ''⎡⎤⎡⎤'''=-=⎢⎥⎢⎥''⎣⎦⎣⎦,2,3,...,hhr hhiLh Lh hhrhhi hhr hhi Lh Lh hhr hhi a a G B a a h n b b B G b b ''-⎡⎤⎡⎤⎡⎤=-=⎢⎥⎢⎥⎢⎥''⎣⎦⎣⎦⎣⎦The total harmonic current of the composite load becomes112012(),()2,3,...,nh h hkr kr hki ki k k hhhrhhi hr h Lh NhLhNh n hhrhhi hi h h hkr kr hki kik k h a a V a V a V a a V I I I I I b b V b b V b V b V h n=≠=≠⎡⎤+++⎢⎥⎢⎥''⎡⎤⎡⎤''=-=-=-⎢⎥⎢⎥⎢⎥''⎣⎦⎣⎦⎢⎥+++⎢⎥⎢⎥⎣⎦=∑∑ (9)By neglecting ''Nh I in the harmonic current of nonlinear load and adding it to the harmonic current of linear load, 'Nh I can then be deemed as harmonic current of thenonlinear load while ''Lh I can be taken as harmonic current of the linear load. ''Nh I =0 means the composite load contains no harmonic sources, while ''0NhI ≠signify that harmonic sources may exist in this composite load. As the neglected term ''Nh I is not dominant, it is obviousthat this simplification does not make significant error on the total harmonic current of nonlinear load. However, it makes the possibility or the harmonic source identification and current separation.3. Identification procedureIn order to identify the existence of harmonic sources in a composite load, the parameters in Eq. (9) should be determined primarily, i.e.[]0122hr h h h rh i hhr hhihnr hni C a a a a a a a a ''= []0122hi h h h rh i hhrhhihnr hni C b b b b b b b b ''=For this purpose, measurement of different supply voltages and corresponding harmoniccurrents of the composite load should be repeatedly performed several times in some short period while keeping the composite load stationary. The change of supply voltage can for example be obtained by switching in or out some shunt capacitors, disconnecting a parallel transformer or changing the tap position of transformers with OLTC. Then, the least squares approach can be used to estimate the parameters by the measured voltages and currents. The identification procedure will be explained as follows.(1) Perform the test for m （2m n ≥）times to get measured fundamental frequency andharmonic voltage and current phasors ()()k k h h V θ∠,()()k k hh I φ∠,()1,2,,,1,2,,k m h n == .(2) For 1,2,,k n = ，transfer the phasors corresponding to zero fundamental voltage phase angle ()1(0)k θ=and change them into orthogonal components, i.e.()()11kkr V V = ()10ki V =()()()()()()()()()()11cos sin kkkkk kkkhr h h hihhV V h V V h θθθθ=-=-()()()()()()()()()()11cos sin k kkkk kkkhrhhhihhI I h I I h φθφθ=-=-,2,3,...,h n =(3)Let()()()()()()()()1221Tk k k k k k k k r i hr hi nr ni VV V V V V V V ⎡⎤=⎣⎦ ,()1,2,,k m = ()()()12Tm X V V V ⎡⎤=⎣⎦ ()()()12T m hr hr hr hrW I I I ⎡⎤=⎣⎦()()()12Tm hi hi hihi W I I I ⎡⎤=⎣⎦ Minimize ()()()211hr mk hr k I C V=-∑ and ()()()211him k hi k IC V=-∑, and determine the parametershr C and hi C by least squares approach as [13]:()()11T T hr hr T T hi hiC X X X W C X X X W --== (10)(4) By using Eq. (9), calculate I0Lh; I0Nh with the obtained Chr and Chi; then the existence of harmonic source is identified and the harmonic current is separated.It can be seen that in the course of model construction, harmonic source identification and harmonic current separation, m times changing of supply system operating condition and measuring of harmonic voltage and currents are needed. More accurate the model, more manipulations are necessary.To compromise the needed times of the switching operations and the accuracy of the results, the proposed model for the nonlinear load (Eq. (7)) and the composite load (Eq. (9)) can be further simplified by only considering the dominant terms in Eq. (7), i.e.01111,Nhr h h hhr hhi hr Nh Nhi ho h hhrhhi hi I a a V a a V I I b b V b b V +⎡⎤⎡⎤⎡⎤⎡⎤==+⎢⎥⎢⎥⎢⎥⎢⎥+⎣⎦⎣⎦⎣⎦⎣⎦2,3,,h n = (11) 01111h h Nh ho h a a V I b b V +⎡⎤'=⎢⎥+⎣⎦01111,hr hhrhhi hr h h h LhNh hi hhr hhihi ho h I a a V a a V I I I I b b V b b V ''+⎡⎤⎡⎤⎡⎤⎡⎤''==-=-⎢⎥⎢⎥⎢⎥⎢⎥''+⎣⎦⎣⎦⎣⎦⎣⎦2,3,,h n = (12) In this case, part equations in the previous procedure should be changed as follows[]01hr h h hhrhhi C a a a a ''= []01hi h h hhrhhiC b b b b ''= ()()()1Tk k k hr hi V V V ⎡⎤=⎣⎦ Similarly, 'Nh I and 'Lh I can still be taken as the harmonic current caused by thenonlinear load and the linear load, respectively.4. Experimental validation4.1. Model accuracyTo demonstrate the validity of the proposed harmonic source models, simulations are performed on the following three kind of typical nonlinear loads: a three-phase six-pulse rectifier, a single-phase capacitor-filtered rectifier and an acarc furnace under stationary operating condition.Diagrams of the three-phase six-pulse rectifier and the single-phase capacitor-filtered rectifier are shown in Figs. 1 and 2 [14,15], respectively, the V –I characteristic of the arc furnace is simplified as shown in Fig. 3 [16].The harmonic currents used in the simulation test are precisely calculated from their mathematical model. As to the supply voltage, VekT1 is assumed to be uniformly distributed between 0.95 and 1.05, VekThr and VekThi ek 1; 2;…;m T are uniformly distributed between20.03 and 0.03 with base voltage 10 kV and base power 1 MVFig. 1. Diagram of three-phase six-pulse rectifier.Fig. 2. Diagram of single-phase capacitor-filtered rectifierFig. 3. Approximate V –I characteristics of arc furnace.Three different models including the harmonic current source (constant current) model, the Norton model and the proposed simplified model are simulated and estimated by the least squares approach for comparison.For the three-phase six-pulse rectifier with fundamental currentI=1.7621; the1 parameters in the simplified model for fifth and seventh harmonic currents are listed in Table 1.To compare the accuracy of the three different models, the mean and standard deviations of the errors on Ihr; Ihi and Ih between estimated value and the simulated actual value are calculated for each model. The error comparison of the three models on the three-phase six-pulse rectifier is shown in Table 2, where mhr; mhi and mha denote the mean, and shr; shi and sha represent the standard deviations. Note that I1 and _Ih in Table 2are the current values caused by rated pure sinusoidal supply voltage.Error comparisons on the single-phase capacitor-filtered rectifier and the arc furnace load are listed in Table 3 and 4, respectively.It can be seen from the above test results that the accuracy of the proposed model is different for different nonlinear loads, while for a certain load, the accuracy will decrease as the harmonic order increase. However, the proposed model is always more accurate than other two models.It can also be seen from Table 1 that the componenta50 t a51V1 and b50 t b51V1 are around 20:0074 t0:3939 0:3865 and 0:0263 t 0:0623 0:0886 while the componenta55V5r and b55V5i will not exceed 0:2676 ￡0:03 0:008 and 0:9675 ￡0:003 0:029; respectively. The result shows that the fifth harmonic current caused by the summation of constant term and the fundamental voltage is about 10 times of that caused by harmonic voltage with same order, so that the formal is dominant in the harmonic current for the three-phase six-pulse rectifier. The same situation exists for other harmonic orders and other nonlinear loads.4.2. Effectiveness of harmonic source identification and current separationTo show the effectiveness of the proposed harmonic source identification method, simulations are performed on a composite load containing linear load (30%) and nonlinear loads with three-phase six-pulse rectifier (30%),single-phase capacitor-filtered rectifier (20%) and ac arc furnace load (20%).For simplicity, only the errors of third order harmonic current of the linear and nonlinear loads are listed in Table 5, where IN3 denotes the third order harmonic current corresponding to rated pure sinusoidal supply voltage; mN3r ;mN3i;mN3a and mL3r ;mL3i;mL3a are error means of IN3r ; IN3i; IN3 and IL3r ; IL3i; IL3 between the simulated actual value and the estimated value;sN3r ;sN3i;sN3a and sL3r ;sL3i;sL3a are standard deviations.Table 2Table 3It can be seen from Table 5 that the current errors of linear load are less than that of nonlinear loads. This is because the errors of nonlinear load currents are due to both the model error and neglecting the components related to harmonic voltages of the same order, whereas only the later components introduce errors to the linear load currents. Moreover, it can be found that more precise the composite load model is, less error is introduced. However, even by using the very simple model (12), the existence of harmonic sources can be correctly identified and the harmonic current of linear and nonlinear loads can be effectively separated. Table 4Error comparison on the arc furnaceTable 55. ConclusionsIn this paper, from an engineering point of view, firstly anew linear model is presented for representing harmonic sources. On the basis of the intrinsic difference between linear and nonlinear loads in their V –I characteristics, and by using the proposed harmonic source model, a new concise principle for identifying harmonic sources and separating harmonic source currents from that of linear loads is proposed. The detailed modeling and identification procedure is also developed based on the least squares approximation approach. Test results on several kinds of typical harmonic sources reveal that the simplified model is of sufficient precision, and is superior to other existing models. The effectiveness of the harmonic source identification approach is illustrated using a composite nonlinear load.AcknowledgementsThe authors wish to acknowledge the financial support by the National Natural Science Foundation of China for this project, under the Research Program Grant No.59737140. 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New York: Wiley; 1985.[14] Xia D, Heydt GT. Harmonic power flow studies. Part I. Formulationand solution. IEEE Trans Power Apparatus Syst 1982;101(6):1257–65.[15] Mansoor A, Grady WM, Thallam RS, Doyle MT, Krein SD, SamotyjMJ. Effect of supply voltage harmonics on the input current of single phase diode bridge rectifier loads. IEEE Trans Power Deliv 1995;10(3):1416–22.[16] Varadan S, Makram EB, Girgis AA. A new time domain voltage source model for an arc furnace using EMTP. IEEE Trans Power Deliv 1996;11(3):1416–22.。
网络毕业设计结论英文
网络毕业设计结论英文The Conclusion of My Network Graduation ProjectAfter months of hard work and dedication, I am pleased to present the conclusion of my network graduation project. This project aimed to explore and analyze various aspects of networking, including its impact on society, the challenges faced, and the potential for future advancements.Throughout the project, I conducted extensive research and analysis, which allowed me to gain a deeper understanding of the subject matter. I explored the evolution of networking, starting from its humble beginnings to the complex and interconnected systems we rely on today. It was fascinating to witness how networking has transformed the way we communicate, collaborate, and access information.One of the key findings of my research was the significant impact of networking on society. The advent of the internet and the subsequent development of networking technologies have revolutionized various sectors, including business, education, healthcare, and entertainment. Networking has facilitated global connectivity, enabling people from different corners of the world to connect and share ideas effortlessly.Moreover, networking has also presented numerous challenges that need to be addressed. One of the most pressing issues is cybersecurity. As our reliance on networking grows, so does the vulnerability to cyber threats. The rise of hacking, data breaches, and identity theft poses a serious threat to individuals,organizations, and even governments. It is crucial for network administrators and policymakers to prioritize cybersecurity measures to ensure the safety and privacy of users.Another challenge is the digital divide, which refers to the gap between those who have access to digital technologies and those who do not. While developed countries enjoy high-speed internet and advanced networking infrastructure, many developing nations still struggle with limited connectivity and lack of resources. Bridging this gap is essential to promote equal opportunities and empower individuals and communities worldwide.Looking ahead, the future of networking holds immense potential. The emergence of technologies such as 5G, artificial intelligence, and the Internet of Things (IoT) promises to revolutionize networking even further. These advancements will enable faster and more reliable connections, facilitate automation and smart systems, and create new opportunities for innovation and growth.However, as we embrace these advancements, it is crucial to consider the ethical implications they may bring. The responsible and ethical use of networking technologies should be at the forefront of our minds. Ensuring privacy, protecting personal data, and addressing the potential negative impacts on employment and social interactions are all vital considerations as we move forward.In conclusion, my network graduation project has provided valuable insights intothe world of networking. It has highlighted the significant impact networking has on society, the challenges it faces, and the potential for future advancements. As we continue to rely on networking technologies, it is essential to prioritize cybersecurity, bridge the digital divide, and approach advancements with a strong ethical framework. By doing so, we can harness the full potential of networking and create a more connected and inclusive world.。
计算机专业毕业设计说明书外文翻译(中英对照)
Talking about security loopholesRichard S. Kraus reference to the core network security business objective is to protect the sustainability of the system and data security, This two of the main threats come from the worm outbreaks, hacking attacks, denial of service attacks, Trojan horse. Worms, hacker attacks problems and loopholes closely linked to, if there is major security loopholes have emerged, the entire Internet will be faced with a major challenge. While traditional Trojan and little security loopholes, but recently many Trojan are clever use of the IE loophole let you browse the website at unknowingly were on the move.Security loopholes in the definition of a lot, I have here is a popular saying: can be used to stem the "thought" can not do, and are safety-related deficiencies. This shortcoming can be a matter of design, code realization of the problem.Different perspective of security loo phole sIn the classification of a specific procedure is safe from the many loopholes in classification.1. Classification from the user groups:● Public loopholes in the software category. If the loopholes in Windows, IEloophole, and so on.● specialized software loophole. If Oracle loopholes, Apach e, etc. loopholes.2. Data from the perspective include :● could not reasonably be read and read data, including the memory of thedata, documents the data, Users input data, the data in the database, network,data transmission and so on.● designa ted can be written into the designated places (including the localpaper, memory, databases, etc.)● Input data can be implemented (including native implementation,according to Shell code execution, by SQL code execution, etc.)3. From the point of view of the scope of the role are :● Remote loopholes, an attacker could use the network and directly throughthe loopholes in the attack. Such loopholes great harm, an attacker can createa loophole through other people's computers operate. Such loopholes and caneasily lead to worm attacks on Windows.● Local loopholes, the attacker must have the machine premise accesspermissions can be launched to attack the loopholes. Typical of the local authority to upgrade loopholes, loopholes in the Unix system are widespread, allow ordinary users to access the highest administrator privileges.4. Trigger conditions from the point of view can be divided into:● Initiative trigger loopholes, an attacker can take the initiative to use the loopholes in the attack, If direct access to computers.● Passive trigger loopholes must be computer operators can be carried out attacks with the use of the loophole. For example, the attacker made to a mail administrator, with a special jpg image files, if the administrator to open image files will lead to a picture of the software loophole was triggered, thereby system attacks, but if managers do not look at the pictures will not be affected by attacks.5. On an operational perspective can be divided into:● File opera tion type, mainly for the operation of the target file path can be controlled (e.g., parameters, configuration files, environment variables, the symbolic link HEC), this may lead to the following two questions: ◇Content can be written into control, the contents of the documents can be forged. Upgrading or authority to directly alter the important data (such as revising the deposit and lending data), this has many loopholes. If history Oracle TNS LOG document can be designated loopholes, could lead to any person may control the operation of the Oracle computer services;◇information content can be output Print content has been contained to a screen to record readable log files can be generated by the core users reading papers, Such loopholes in the history of the Unix system crontab subsystem seen many times, ordinary users can read the shadow ofprotected documents;● Memory coverage, mainly for memory modules can be specified, writecontent may designate such persons will be able to attack to enforce the code (buffer overflow, format string loopholes, PTrace loopholes, Windows 2000 history of the hardware debugging registers users can write loopholes), or directly alter the memory of secrets data.● logic errors, such wide gaps exist, but very few changes, so it is difficult todiscern, can be broken down as follows : ◇loopholes competitive conditions (usually for the design, typical of Ptrace loopholes, The existence of widespread document timing of competition) ◇wrong tactic, usually in design. If the history of the FreeBSD Smart IO loopholes. ◇Algorithm (usually code or design to achieve), If the history of Microsoft Windows 95/98 sharing password can easily access loopholes. ◇Imperfections of the design, such as TCP / IP protocol of the three-step handshake SYN FLOOD led to a denial of service attack. ◇realize the mistakes (usually no problem for the design, but the presence of coding logic wrong, If history betting system pseudo-random algorithm)● External orders, Typical of external commands can be controlled (via the PATH variable, SHELL importation of special characters, etc.) and SQL injection issues.6. From time series can be divided into:● has long found loopholes: manufacturers already issued a patch or repairmethods many people know already. Such loopholes are usually a lot of people have had to repair macro perspective harm rather small.● recently discovered loophole: manufacturers just made patch or repairmethods, the people still do not know more. Compared to greater danger loopholes, if the worm appeared fool or the use of procedures, so will result in a large number of systems have been attacked.● 0day: not open the loophole in the private transactions. Usually such loopholes to the public will not have any impact, but it will allow an attacker to the targetby aiming precision attacks, harm is very great.Different perspective on the use of the loopholesIf a defect should not be used to stem the "original" can not do what the (safety-related), one would not be called security vulnerability, security loopholes and gaps inevitably closely linked to use.Perspective use of the loopholes is:● Data Perspective: visit had not visited the data, including reading and writing.This is usually an attacker's core purpose, but can cause very serious disaster (such as banking data can be written).● Competence Perspective: Major Powers to bypass or p ermissions. Permissionsare usually in order to obtain the desired data manipulation capabilities.● Usability perspective: access to certain services on the system of controlauthority, this may lead to some important services to stop attacks and lead to a denial of service attack.● Authentication bypass: usually use certification system and the loopholes willnot authorize to access. Authentication is usually bypassed for permissions or direct data access services.● Code execution perspective: mainly procedures for the importation of thecontents as to implement the code, obtain remote system access permissions or local system of higher authority. This angle is SQL injection, memory type games pointer loopholes (buffer overflow, format string, Plastic overflow etc.), the main driving. This angle is usually bypassing the authentication system, permissions, and data preparation for the reading.Loopholes explore methods mustFirst remove security vulnerabilities in software BUG in a subset, all software testing tools have security loopholes to explore practical. Now that the "hackers" used to explore the various loopholes that there are means available to the model are:● fuzz testing (black box testing), by constructing procedures may lead toproblems of structural input data for automatic testing.● FOSS audit (White Box), now have a series of tools that can assist in thedetection of the safety procedures BUG. The most simple is your hands the latest version of the C language compiler.● IDA anti-compilation of the audit (gray box testing), and above the sourceaudit are very similar. The only difference is that many times you can obtain software, but you can not get to the source code audit, But IDA is a very powerful anti-Series platform, let you based on the code (the source code is in fact equivalent) conducted a safety audit.● dynamic tracking, is the record of proceedings under different conditions andthe implementation of all security issues related to the operation (such as file operations), then sequence analysis of these operations if there are problems, it is competitive category loopholes found one of the major ways. Other tracking tainted spread also belongs to this category.● patch, the software manufacturers out of the question usually addressed in thepatch. By comparing the patch before and after the source document (or the anti-coding) to be aware of the specific details of loopholes.More tools with which both relate to a crucial point: Artificial need to find a comprehensive analysis of the flow path coverage. Analysis methods varied analysis and design documents, source code analysis, analysis of the anti-code compilation, dynamic debugging procedures.Grading loopholesloopholes in the inspection harm should close the loopholes and the use of the hazards related Often people are not aware of all the Buffer Overflow Vulnerability loopholes are high-risk. A long-distance loophole example and better delineation:●R emote access can be an OS, application procedures, version information.●open unnecessary or dangerous in the service, remote access to sensitiveinformation systems.● Remote can be restricted for the documents, data reading.●remotely important or res tricted documents, data reading.● may be limited for long-range document, data revisions.● Remote can be restricted for important documents, data changes.● Remote can be conducted without limitation in the important documents, datachanges, or for general service denial of service attacks.● Remotely as a normal user or executing orders for system and network-leveldenial of service attacks.● may be remote management of user identities to the enforcement of the order(limited, it is not easy to use).● can be remote management of user identities to the enforcement of the order(not restricted, accessible).Almost all local loopholes lead to code execution, classified above the 10 points system for:●initiative remote trigger code execution (such a s IE loophole).● passive trigger remote code execution (such as Word gaps / charting softwareloopholes).DEMOa firewall segregation (peacekeeping operation only allows the Department of visits) networks were operating a Unix server; operating systems only root users and users may oracle landing operating system running Apache (nobody authority), Oracle (oracle user rights) services.An attacker's purpose is to amend the Oracle database table billing data. Its possible attacks steps:● 1. Access pea cekeeping operation of the network. Access to a peacekeepingoperation of the IP address in order to visit through the firewall to protect the UNIX server.● 2. Apache services using a Remote Buffer Overflow Vulnerability direct accessto a nobody's competence hell visit.● 3. Using a certain operating system suid procedure of the loophole to upgradetheir competence to root privileges.● 4. Oracle sysdba landing into the database (local landing without a password).● 5. Revised target table data.Over five down for process analysis:●Step 1: Authentication bypass●Step 2: Remote loopholes code execution (native), Authentication bypassing ● Step 3: permissions, authentication bypass● Step 4: Authentication bypass● Step 5: write data安全漏洞杂谈Richard S. Kraus 网络安全的核心目标是保障业务系统的可持续性和数据的安全性，而这两点的主要威胁来自于蠕虫的暴发、黑客的攻击、拒绝服务攻击、木马。
网络工程毕业外文翻译英文
WIRELESS LANIn just the past few years, wireless LANs have come to occupy a significant niche in the local area network market. Increasingly, organizations are finding that wireless LANs are an indispensable adjunct to traditional wired LANs, as they satisfy requirements for mobility, relocation, ad hoc networking, and coverage of locationsdifficult to wire. As the name suggests, a wireless LAN is one that makes use of a wireless transmission medium. Until relatively recently, wireless LANs were little used; the reasons for this included high prices, low data rates, occupational safety concerns, and licensing requirements. As these problems have been addressed, the popularity of wireless LANs has grown rapidly.In this section, we first look at the requirements for and advantages of wireless LANs, and then preview the key approaches to wireless LAN implementation. Wireless LANs ApplicationsThere are four application areas for wireless LANs: LAN extension, crossbuilding interconnect, nomadic access, and ad hoc networks. Let us consider each of these in turn.LAN ExtensionEarly wireless LAN products, introduced in the late 1980s, were marketed as substitutes for traditional wired LANs. A wireless LAN saves the cost of the installation of LAN cabling and eases the task of relocation and other modifications to network structure. However, this motivation for wireless LANs was overtaken by events. First, as awareness of the need for LAN became greater, architects designed new buildings to include extensive prewiring for data applications. Second, with advancesin data transmission technology, there has been an increasing reliance on twisted pair cabling for LANs and, in particular, Category 3 unshielded twisted pair. Most older building are already wired with an abundance of Category 3 cable. Thus, the use of a wireless LAN to replace wired LANs has not happened to any great extent.However, in a number of environments, there is a role for the wireless LAN as an alternative to a wired LAN. Examples include buildings with large open areas, such as manufacturing plants, stock exchange trading floors, and warehouses; historicalbuildings with insufficient twisted pair and in which drilling holes for new wiring is prohibited; and small offices where installation and maintenance of wired LANs is not economical. In all of these cases,a wireless LAN provides an effective and more attractive alternative. In most of these cases, an organization will also have a wired LAN to support servers and some stationary workstations. For example, a manufacturing facility typically has an office area that is separatefrom the factory floor but which must be linked to it for networking purposes. Therefore, typically, a wireless LAN will be linked into a wired LAN on the same premises. Thus, this application area is referred to as LAN extension.Cross-Building InterconnectAnother use of wireless LAN technology is to connect LANs in nearby buildings, be they wired or wireless LANs. In this case, a point-to-point wireless link is used between two buildings. The devices so connected are typically bridges or routers. This single point-to-point link is not a LAN per se, but it is usual to include this application under the heading of wireless LAN.Nomadic AccessNomadic access provides a wireless link between a LAN hub and a mobile data terminal equipped with an antenna, such as a laptop computer or notepad computer. One example of the utility of such a connection is to enable an employee returning from a trip to transfer data from a personal portable computer to a server in the office. Nomadic accessis also useful in an extended environment such as a campus or a business operating out of a cluster of buildings. In both of these cases,users may move around with their portable computers and may wish access to the servers on a wired LAN from various locations.Ad Hoc NetworkingAn ad hoc network is a peer-to-peer network (no centralized server) set up temporarily to meet some immediate need. For example, a group of employees, each with a laptop or palmtop computer, may convene in a conference room for a business or classroom meeting. The employees link their computers in a temporary network just for the duration of the meeting.Wireless LAN RequirementsA wireless LAN must meet the same sort of requirements typical of any LAN, including high capacity, ability to cover short distances, full connectivity among attached stations, and broadcast capability. In addition, there are a number of requirements specific to the wireless LAN environment. The following are among the most important requirements for wireless LANs:Throughput. The medium accesscontrol protocol should make as efficient use as possible of the wireless medium to maximize capacity.Number of nodes. Wireless LANs may need to support hundreds of nodes across multiple cells.Connection to backbone LAN. In most cases, interconnection with stations on a wired backbone LAN is required. For infrastructure wireless LANs, this is easily accomplished through the use of control modules that connect to both types of LANs. There may also need to be accommodation for mobile users and ad hoc wireless networks.Service area. A typical coverage area for a wireless LAN may be up to a 300 to 1000 foot diameter.Battery power consumption. Mobile workers use battery-powered workstations that need to have a long battery life when used with wireless adapters. This suggests that a MAC protocol that requires mobile nodes to constantlymonitor accesspoints or to engage in frequent handshakes with a base stationis inappropriate.Transmission robustness and security. Unless properly designed, a wireless LAN may be interference-prone and easily eavesdroppedupon. The design of a wireless LAN must permit reliable transmission even in a noisy environment and should provide some level of security from eavesdropping.Collocated network operation. As wireless LANs become more popular, it is quite likely for two of them to operate in the same area or in some area where interference between the LANs is possible. Such interference may thwart the normal operation of a MAC algorithm and may allow unauthorized access to a particular LAN.License-free operation. Users would prefer to buy and operate wireless LAN products without having to secure a license for the frequency band used by the LAN.HandoWroaming. The MAC protocol used in the wireless LAN should enable mobile stations to move from one cell to another.Dynamic configuration. The MAC addressing and network management aspects of the LAN should permit dynamic and automated addition, deletion, and relocation of end systems without disruption to other users.Physical Medium SpecificationThree physical media are defined in the current 802.11 standard:Infrared at 1 Mbps and 2 Mbps operating at a wavelength between 850 and 950 nm. Direct-sequence spread spectrum operating in the 2.4-GHz ISM band. Up to 7 channels, each with a data rate of 1 Mbps or 2 Mbps, can be used.Frequency-hopping spread spectrum operating in the 2.4-GHz ISM band. The details of this option are for further study.Wireless LAN TechnologyWireless LANs are generally categorized according to the transmission techniquethat is used. All current wireless LAN products fall into one of the following categories:Infrared (IR) LANs. An individual cell of an IR LAN is limited to a single room, as infrared light does not penetrate opaque walls.Spread Spectrum LANs. This type of LAN makes use of spread spectrum transmission technology. In most cases, these LANs operate in the ISM (Industrial, Scientific, and Medical) bands, so that no FCC licensing is required for their use in the U.S. Narrowband Microwave. These LANs operate at microwave frequencies but do not use spread spectrum. Some of these products operate at frequencies that require FCC licensing, while others use one of the unlicensed ISM bands.A set of wireless LAN standards has been developed by the IEEE 802.11 committee. The terminology and some of the specific features of 802.11 are unique to this standard and are not reflected in all commercial products. However, it is useful to be familiar with the standard as its features are representative of required wireless LAN capabilities.The smallest building block of a wireless LAN is a basic service set (BSS), whichconsists of some number of stations executing the same MAC protocol and competing for access to the same shared medium. A basic service set may be isolated, or it may connect to a backbone distribution system through an access point. The access point functions as a bridge. The MAC protocol may be fully distributed or controlled by a central coordination function housed in the access point. The basic service set generally correspondsto what is referred to as a cell in the literature. An extended service set (ESS) consists of two or more basic service sets interconnected by a distribution system. Typically, the distribution system is a wired backbone LAN. The extended service set appears as a single logical LAN to the logical link control (LLC) level. The standard defines three types of stations, based on mobility: No-transition. A station of this type is either stationary or moves only within the direct communication range of the communicating stations of a single BSS. BSS-transition. This is defined as a station movement from one BSS to another BSS within the same ESS. In this case, delivery of data to the station requires that the addressing capability be able to recognize the new location of the station. ESS-transition. This is defined as a station movement from a BSS in one ESS to a BSS within another ESS. This case is supported only in the sense that the station can move. Maintenance of upper-layer connections supported by 802.11 cannot be guaranteed. In fact, disruption of service is likely to occur. details of this option are for further study.The 802.11 working group considered two types of proposals for a MAC algorithm: distributed-access protocols which, like CSMAICD, distributed the decision to transmit over all the nodes using a carrier-sense mechanism; and centralized access protocols, which involve regulation of transmission by a centralized decision maker. A distributed access protocol makes sense of an ad hoc network of peer workstations and may also be attractive in other wireless LAN configurations that consist primarily of bursty traffic.A centralized access protocol is natural for configurations in which a number of wireless stations are interconnected with each other and with some sort of base station that attaches to a backbone wired LAN; it is especially useful if some of the data is time-sensitive or high priority.The end result of the 802.11 is a MAC algorithm called DFWMAC (distributedfoundation wireless MAC) that provides a distributed access-control mechanism with an optional centralized control built on top of that. Figure 13.20 illustrates the architecture. The lower sublayer of the MAC layer is the distributed coordination function (DCF). DCF uses a contention algorithm to provide access to all traffic. Ordinary asynchronous traffic directly uses DCF. The point coordination function (PCF) is a centralized MAC algorithm used to provide contention-free service. PCF is built on top of DCF and exploits features of DCF to assure access for its users. Let us consider these two sublayers in turn. Distributed Coordination FunctionThe DCF sublayer makes use of a simple CSMA algorithm. If a station has a MAC frame to transmit, it listens to the medium. If the medium is idle, the station may transmit; otherwise, the station must wait until the current transmission is complete before transmitting. The DCF does not include a collision-detection function (i.e., CSMAICD) because collision detection is not practical on a wireless network. The dynamic range of the signals on the medium is very large, so that a transmitting station cannot effectively distinguish incoming weak signals from noise and the effects of its own transmission. To ensure the smooth and fair functioning of this algorithm, DCF includes a set of delays that amounts to a priority scheme. Let us start by considering a single delay known as an interframe space (IFS). In fact, there are three different IFS values, but the algorithm is best explained by initially ignoring this detail. Using an IFS, the rules for CSMA access are as follows:I. A station with a frame to transmit senses the medium. If the medium is idle, the station waits to see if the medium remains idle for a time equal to IFS, and, if this is so, the station may immediately transmit.2. If the medium is busy (either because the station initially finds the medium busy or because the medium becomes busy during the IFS idle time), the station defers transmission and continues to monitor the medium until the current transmission is over.3. Once the current transmission is over, the station delays another IFS. If the medium remains idle for this period, then the station backs off using a binary exponential backoff scheme and again senses the medium. If the medium is still idle, the station maytransmit.Point Coordination FunctionPCF is an alternative access method implemented on top of the DCF. The operation consists of polling with the centralized polling master (point coordinator). The point coordinator makes use of PIFS when issuing polls. Because PIFS is smaller than DIFS, the point coordinator can seize the medium and lock out all asynchronous traffic while it issues polls and receives responses.As an extreme, consider the following possible scenario. A wireless network is configured so that a number of stations with time-sensitive traffic are controlled by the point coordinator while remaining traffic, using CSMA, contends for access.The point coordinator could issue polls in a round-robin fashion to all stations configured for polling. When a poll is issued, the polled station may respond using SIFS. If the point coordinator receives a response, it issues another poll using PIFS. If no response is received during the expected turnaround time, the coordinator issues a poll. If the discipline of the preceding paragraph were implemented, the point coordinator would lock out all asynchronous traffic by repeatedly issuing polls. To prevent this situation, an interval known as the superframe is defined. During the first part of this interval, the point coordinator issues polls in a round-robin fashion to all stations configured for polling. The point coordinator then idles for the remainder of the superframe, allowing a contention period for asynchronous access.At the beginning of a superframe, the point coordinator may optionally seize control and issue polls fora give period of time. This interval varies because of the variable frame size issued by responding stations. The remainder of the superframe is available for contention-based access. At the end of the superframe interval, the point coordinator contends for access to the medium using PIFS. If the medium is idle, the point coordinator gains immediate access, and a full superframe period follows. However, the medium may be busy at the end of a superframe. In this case, the point coordinator must wait until the medium is idle to gain access; this results in a foreshortened superframe period for the next cycle.。
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附件1：外文资料翻译译文彗星：基于组件的嵌入式实时数据库亚历山大Tešanovi'c约尔根汉森林雪平大学计算机科学林雪平，瑞典（alete，处jorha）@ ida.liu.se达格哈马尼斯特伦克里斯特伦麦拉达愣大学计算机工程系摘要本文介绍的裁剪概念嵌入式实时数据库调用彗星。
设计数据库是裁剪，并同时满足实时（时间）的要求和最小的资源（空间）要求的嵌入式和实时系统，需要利用各方面的组件和概念嵌入式实时数据库开发。
关键词: 实时数据库；嵌入式；资源管理1导言在过去几年中部署的嵌入式和实时系统已急剧增加[13]。
数据的管理对由实时数据系统需要在增加，因此需要一个有效率和结构化数据管理。
因此，数据库的功能需要提供存储和对数据的实时操作的支持和嵌入式系统，但它也必须满足他们的要求无论从嵌入式系统还是实时系统。
实时系统建造出程序通常被称作任务。
一个实时的正确性系统依赖于计算出合乎逻辑的结果与该结果产生时的时间，被精确描述为[12时间限制]。
最常用的时间约束，一个实时系统必须满足完成任务的最后期限。
而且，在该系统中的数据通常与时间的限制相联系。
例如，绝对的动态有效时段[10]。
因此，实时数据库必须确保数据数据库在逻辑上和时间上保持一致。
相反，隐藏在一个应用程序的嵌入式数据库内部的应用程序，设备嵌入式数据库是一个数据库在一个嵌入式系统所存在。
我们专注于设备嵌入式数据库，是指嵌入式数据库。
一个嵌入式数据库的主要目标低内存使用，也就是说，小的内存占用，可移植性在不同的操作系统平台来实现有效的资源管理。
例如，在CPU 使用率最小化，有能力运行长时间没有管理[9]。
为实时和嵌入式系统设计数据库时的两个方面优点：时间和空间。
这可以进一步完善，包括：（一）功能队大小权衡，（二）功能方面的时间要求（三）生产成本。
因此，为了应付这些挑战，我们提出了一种实时基于数据库平台的组件的概念和方面：康明（基于构件的嵌入式实时实时数据库系统）从组件库的重用形式的势头来讲，为了降低生产成本，再利用和组件的重用是关键，例如COM，CORBA和JavaBeans的。
有问题除了意味着纳入基本组件在思想方面的面向编程（AOP）和数据库的发展。
因此，我们区分彗星功能分解和貌分解数据库系统。
功能分解是一种方式分解成组件的数据库系统。
组件职能单位是包含的主要结构数据库系统和执行核心功能的系统。
貌分解是一种分离方法贯穿在制度的考虑，例如，代码，不能被封装在一个职能部门，而是纠缠整个系统。
因此，各方面的非功能单位包含数据库的二级结构并参照组件和其他方面。
本文组织如下。
对嵌入式实时数据库系统的组件化动机是由于在第2，第3节的主要挑战组件的开发和基于嵌入式实时数据库系统。
有关的工作是讨论第4条。
本文结束含主要结论摘要和我们今后的研究方向。
2. 目的2.1嵌入式和RealTime数据库现有的商业嵌入式数据库系统，例如，多面体，RDM的，V elocis，Pervasive.SQL，Berkeley DB的，和TimesTen，有不同的特点和设计在考虑具体的应用。
他们支持不同的数据模型。
例如，关系队对象关系模式，不同的操作系统平台。
而且，他们有不同的内存需求，并提供对不同类型的接口在用户的访问数据数据库。
应用程序开发人员必须认真选择嵌入式数据库的应用程序要求，并找到之间的平衡，并提供所需的数据库功能。
因此，寻找合适的嵌入式数据库是一个时间耗时，昂贵和困难的过程，往往很多的妥协。
另外，设计人员正面临着进化的数据库，即问题，数据库必须能够在生命进化的嵌入式系统的时间，关于新的功能。
但是，传统的数据库系统是很难修改或扩展新的所需的功能，主要是因为他们单片结构和功能的事实，即增加额外的结果系统复杂性。
虽然大量研究实时数据库已经完成，在过去几年，它主要集中关于并发控制，事务各项计划调度，并记录和恢复，并减少对可配置的软件体系结构。
研究项目正在建设，例如ARTRTDB实时数据库平台，[7]，蜂窝[14]，契约[1]和RODAIN [8]，具有整体结构，并为建立一个特定的实时应用程序。
因此，howto问题，使发展一种嵌入式数据库系统，用户可定制不同的嵌入式和实时应用程序时。
2.2定制的成分拥有嵌入式实时数据库系统，将允许添加或更换其结构功能，基于组件的方式将是有益的数原因：（一）复杂的数据库系统及维修费用将减少;（二）申请不必支付不必要的功能，使用性能和成本的刑罚，因为不必要的组件没有被添加到系统;及（iii）建立一个系统的演变会简化，因为随着新规定功能的新元件可以插入到系统中。
虽然一些主要的数据库供应商（例如，甲骨文，Informix的，Sybase和微软）已经认识到基于组件的开发带来巨大的利益，他们基于组件的解决方案是有限的裁剪条件同，在大多情况下，不支持的分析组成的系统。
就我们所知，只有最好的现有的研究旨在建立全面配置数据库管理系统（DBMS）是童装[4]。
童装组成部分介绍了一个可配置的数据库管理系统（数据库管理系统的子系统），例如，对象管理和事务管理。
这个系统是定制改进后可重复使用的架构，以及零部件存储在一个图书馆。
童装有一个明确的发展过程中，可配置支持和可选分析工具（这是在其他componentbased失踪数据库解决方案，如大蒜[3]，纳瓦霍[2]）。
从现实的角度当时所有的方法讨论不执行的实时行为。
嵌入式相关问题如低，资源消耗系统不在讨论范围内。
工具支持的组成设计和对组成系统的分析是必要的，以及最基于组件的讨论并没有提供足够的系统尤其是配置和分析支持（重要实时系统）。
3．彗星3.1方法论彗星平台由两部分组成。
第一部分是一个组件库，它拥有一套组件和方面。
第二部分是工具，根据对申请的要求，设计时支持建立嵌入式数据库使用组件和问题从库中。
我们的做法包括提取通过研究了一些相关的数据库应用的特点个案研究的第一阶段，由一个执行;在下一阶段，以及设计评估工具和数据库架构上的一些个案研究最后阶段。
3.2 问题对平台的出发点是设计一个基于组件的数据库。
在这方面，我们面临着下面的问题。
1．我们如何封装不同的数据库功能/成组件的嵌入式和实时系统提供合适的服务？这还包括：（一）界定数据库组件模型适合实时和嵌入式系统;（二）指定组件的由于各方面的实时属性，这样的组成体系是可以预见和（三）确定规则连接组件，使得组成的系统可靠，满足了系统的要求。
2．我们如何确保可预测的组成数据库系统，对于响应时间，内存使用和CPU 的使用情况？此外，面临的挑战是确保易于集成的组成数据库系统到运行时环境实时系统的时间，确保行为系统。
如何解决这些问题是一项艰巨的任务，数理由。
首先，彗星数据库应适当低资源系统，主要系统的限制内存和功耗。
因此，适当的该数据库的功能分解应作出这样的功能，最有可能（不）被大多数嵌入式系统需要的是确定和封装成组件。
第二，彗星数据库应确保可预测的交易执行。
此外，大多数嵌入式系统正在实施mainmemory，这就要求彗星数据库是一个mainmemory数据库。
我们举一个例子，这些数据的挑战在汽车控制应用一流的管理问题。
示例中的讨论，主要是基于案例研究在沃尔沃建筑内执行的项目设备元件公司，瑞典，我们分析在现有数据的实时系统管理使用控制轮式装载机和详尽的运输商。
例如车辆控制系统图1彗星的功能分解通常，在汽车行业控制系统硬实时安全关键系统组成的几个分布式节点。
每个节点实现特定功能并可以被看作是一个独立的实时系统，例如，节点可以实现传输，引擎或工具职能。
节点的大小差别很大，从非常小的节点，例如，32 KB 的内存，以较大的节点，例如，64 KB的RAM和512 KB闪存。
根据在节点的和现有的功能记忆，不同的数据库的实现是必要的。
例如，在安全任务的关键节点往往是不可中断并定于离线，避免并发只允许一个任务是在任何特定时间活跃。
这反过来又影响了数据库的功能得到的有关并发控制节点。
在这一点上，我们需要澄清的任务之间的关系和交易。
在控制应用中，像这样的，任务正在对所有数据的更新。
因此，从数据库的角度来看，一个任务执行更新可以被视为一个数据库事务，因为它封装（一个或多个）交易。
不太关键的节点，而抢占任务，将需要并发控制机制。
此外，一些节点所需的关键数据被记录，例如，警告和错误，就需要备份启动和关闭，而其他节点只有内存（主内存），并且不需要非易失性后备设施从数据库中。
对来自不同的功能需要讨论不同节点的数据库可继续进一步，但我们与这个简短的讨论的目的是要表明引入基于组件的数据库有前提的，因为它会允许数据库进行调整，以适应一个实时的需要在每个节点应用方面的内存消耗，并发控制，恢复，不同的调度技术交易和存储模型。
这有助于优化每个节点的内存消耗，并允许数据库结合起来更容易与运行时环境。
3.3功能和貌分解为了满足定制及协调的要求有具体的实时和彗星数据库嵌入式应用，数据库的分解系统必须做到了一级的功能（功能分解），以及一个方面的水平（貌分解）。
利用各方面的关注点分离，允许设计功能组件，交叉实时截止具体和数据库的具体方面，例如，实时方面和交易方面，分别为。
例如，组件，控制访问在内存中的数据不仅会管理检索和数据存储在一个特定的内存类型（内存类型可以被认为作为一个方面），而且还管理实时的时间属性数据对象存储在内存（实时数据的时间限制也可以看作是一个方面）。
图2在一个应用层彗星貌的分解彗星功能和貌的分解分别见图1和2。
貌分解也意味着组件使用系统的组成不再传统的黑盒子components2，而他们是灰色的，我们可以修改他们的内部行为是应用不同的方面。
由于问题被认为是一个系统属性影响其性能或语义，以及跨削减该系统的功能[6]，这方面可确定在一个嵌入式实时数据库系统可以有许多。
因此，我们必须认真贯彻落实这两个组件定义某些功能和不同的方面横切这些组件。
3.4 彗星功能分解在我们确定彗星的初步设计6个组成部分（见图1）：（一）用户界面，一个组件使用户可以在数据库中访问数据，并做查询处理;（2）序列化的经理，一个组件这是在确保交易序列负责，并执行调度与并发控制（消委会），（三）锁定的经理，一个组件处理锁定数据;（四）经理指数，交易的一个组件随着数据索引;（五）恢复管理器，一个组件在回收费用和数据记录在数据库;和（六）内存管理器，一个组件允许访问可能在不同的内存中存储的数据媒体的原则，使我们这个具有分解彗星功能的数据库主要是需要有是松散耦合的交换单位功能。
但强大的凝聚力，即内在的力量有些是自然的选择，有一个用户界面一个组件，因为不同的应用程序可能需要不同的访问数据的方式在系统内。
图3 在一个嵌入式分类的各个方面实时数据库系统在控制应用中讨论过，有不需要复杂的场景调度交易与并发控制，例如，硬实时系统只允许一个事务访问的数据库时间。