计算机专业的外文文献.pdf

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

Management Information System Overview Management Information System is that we often say that the MIS, is a human, computers and other information can be composed of the collection, transmission, storage, maintenance and use of the system, system, emphasizing emphasizing the the management, management, management, stressed stressed stressed that that the modern information society In the increasingly popular. MIS is a new subject, it across a number of areas, such as scientific scientific management management management and and and system system system science, science, science, operations operations operations research, research, research, statistics statistics statistics and and and computer computer science. In these subjects on the basis of formation of information-gathering and processing methods, thereby forming a vertical and horizontal weaving, and systems. The 20th century, along with the vigorous development of the global economy, many economists have proposed a new management theory. In the 1950s, Simon made dependent on information management and decision-making ideas. Wiener published the same period of the control theory, that he is a management control process. 1958, Gail wrote: "The management will lower the cost of timely and accurate information to b etter control." During better control." During this period, accounting for the beginning of the computer, data processing in the term.1970, Walter T . Kenova just to the management information system under a definition of the . Kenova just to the management information system under a definition of the term: "verbal or written form, at the right time to managers, staff and outside staff for the past, present, the projection of future Enterprise and its environment-related information 原文请找腾讯3249114六,维^论~文.网 no no application application application model, model, model, no no mention mention of of computer applications. 1985, management information systems, the founder of the University of Minnesota professor of management at the Gordon B. Davis to a management information system a more complete definition of "management information system is a computer hardware and software resources, manual operations, analysis, planning , Control and decision -making model and the database - System. System. It It provides information to to support support enterprises enterprises or or organizations organizations of of the operation, management and decision-making function. "Comprehensive definition of this Explained Explained that that that the the the goal goal goal of of of management management management information information information system, system, system, functions functions functions and and and composition, composition, composition, but but also reflects the management information system at the time of level.With the continuous improvement of science and technology, computer science increasingly mature, the computer has to be our study and work on the run along. Today, computers are already already very low price, performance, but great progress, and it was used in many areas, the very low price, performance, but great progress, and it was used in many areas, the computer computer was was was so so so popular popular popular mainly mainly mainly because because because of of of the the the following following following aspects: aspects: aspects: First, First, First, the the the computer computer computer can can substitute for many of the complex Labor. Second, the computer can greatly enhance people's work work efficiency. efficiency. efficiency. Third, Third, Third, the the the computer computer computer can can can save save save a a a lot lot lot of of of resources. resources. resources. Fourth, Fourth, Fourth, the the the computer computer computer can can make sensitive documents more secure.Computer application and popularization of economic and social life in various fields. So that the original old management methods are not suited now more and social development. Many people still remain in the previous manual. This greatly hindered the economic development of mankind. mankind. In recent years, with the University of sponsoring scale is In recent years, with the University of sponsoring scale is growing, the number of students students in in in the the the school school school also also also have have have increased, increased, increased, resulting resulting resulting in in in educational educational educational administration administration administration is is is the the growing complexity of the heavy work, to spend a lot of manpower, material resources, and the existing management of student achievement levels are not high, People have been usin g the traditional method of document management student achievement, the management there are many shortcomings, such as: low efficiency, confidentiality of the poor, and Shijianyichang, will have a large number of of documents documents documents and and data, which is is useful useful for finding, finding, updating updating and maintaining Have brought a lot of difficulties. Such a mechanism has been unable to meet the development of the times, schools have become more and more day -to-day management of a bottleneck. bottleneck. In In In the the the information information information age age age this this this traditional traditional traditional management management management methods methods methods will will will inevitably inevitably inevitably be be computer-based information management replaced. As As part part part of of of the the the computer computer computer application, application, application, the the the use use use of of of computers computers computers to to to students students students student student student performance performance information for management, with a manual management of the incomparable advantages for example: example: rapid rapid rapid retrieval, retrieval, retrieval, to to to find find find convenient, convenient, convenient, high high high reliability reliability reliability and and and large large large capacity capacity capacity storage, storage, storage, the the confidentiality confidentiality of of of good, good, good, long long long life, life, life, cost cost cost Low. Low. Low. These These These advantages advantages advantages can can can greatly greatly greatly improve improve improve student student performance management students the efficiency of enterprises is also a scientific, standardized standardized management, management, management, and and and an an an important important important condition condition condition for for for connecting connecting connecting the the the world. world. world. Therefore, Therefore, the development of such a set of management software as it is very necessary thing.Design ideas are all for the sake of users, the interface nice, clear and simple operation as far as possible, but also as a practical operating system a good fault-tolerant, the user can misuse a timely manner as possible are given a warning, so that users timely correction . T o take full advantage advantage of the of the functions of visual FoxPro, design p owerful software powerful software at the same time, as much as possible to reduce the occupiers system resources. Visual FoxPro the command structure and working methods: Visual FoxPro was originally originally called called FoxBASE, FoxBASE, the the U.S. U.S. Fox Fox Software has introduced introduced a a database products, products, in in the run on DOS, compatible with the abase family. Fox Fox Software Software Microsoft acquisition, to be developed so that it can run on Windows, and changed its name to Visual FoxPro. Visual FoxPro is a powerful relational database rapid application development tool, tool, the the the use use use of of of Visual Visual Visual FoxPro FoxPro FoxPro can can can create create create a a a desktop desktop desktop database database database applications, applications, applications, client client client / / / server server applications applications and and and Web Web Web services services services component-based component-based component-based procedures, procedures, procedures, while while while also also also can can can use use use ActiveX ActiveX controls or API function, and so on Ways to expand the functions of Visual FoxPro.1651First, work methods 1. Interactive mode of operation (1) order operation VF in the order window, through an order from the keyboard input of all kinds of ways to complete the operation order. (2) menu operation VF use menus, windows, dialog to achieve the graphical interface features an interactive operation. (3) aid operation VF in the system provides a wide range of user-friendly operation of tools, such as the wizard, design, production, etc.. 2. Procedure means of implementation VF in the implementation of the procedures is to form a group of orders and programming language, an extension to save. PRG procedures in the document, and then run through the automatic implementation of this order documents and award results are displayed. Second, the structure of command 1. Command structure 2. VF orders are usually composed of two parts: The first part is the verb order, also known as keywords, for the operation of the designated order functions; second part of the order clause, for an order that the operation targets, operating conditions and other information . VF order form are as follows: 3. <Order verb> "<order clause>" 4. Order in the format agreed symbols 5. 5. VF in the order form and function of the use of the symbol of the unity agreement, the meaning of VF in the order form and function of the use of the symbol of the unity agreement, the meaning of these symbols are as follows: 6. Than that option, angle brackets within the parameters must be based on their format input parameters. 7. That may be options, put in brackets the parameters under specific requ ests from users choose to enter its parameters. 8. Third, the project manager 9. Create a method 10. command window: CREA T PROJECT <file name> T PROJECT <file name> 11. Project Manager 12. tab 13. All - can display and project management applications of all types of docume nts, "All" tab contains five of its right of the tab in its entirety . 14. Data - management application projects in various types of data files, databases, free form, view, query documents. 15. Documentation - display 原文请找腾讯原文请找腾讯3249114六,维^论~文.网 , statements, documents, labels and other documents. 16. Category - the tab display and project management applications used in the class library documents, including VF's class library system and the user's own design of the library. 17. Code - used in the project management procedures code documents, such as: program files (. PRG), API library and the use of project management for generation of applications (. APP). 18. (2) the work area 19. The project management work area is displayed and management of all types of document window. 20. (3) order button 21. Project Manager button to the right of the order of the work area of the document window to provide command. 22. 4, project management for the use of 23. 1. Order button function 24. New - in the work area window selected certain documents, with new orders button on the new document added to the project management window. 25. Add - can be used VF "file" menu under the "new" order and the "T ools" menu under the "Wizard" order to create the various independent paper added to the project manager, unified organization with management. 26. Laws - may amend the project has been in existence in the various documents, is still to use such documents to modify the design interface. 27. Sports - in the work area window to highlight a specific document, will run the paper.28. Mobile - to check the documents removed from the project. 29. 29. Even Even Even the the the series series series - - - put put put the the the item item item in in in the the the relevant relevant relevant documents documents documents and and and even even even into into into the the the application application executable file. Database System Design :Database design is the logical database design, according to a forthcoming data classification system and the logic of division-level organizations, is user-oriented. Database design needs of various departments of the integrated enterprise archive data and data needs analysis of the relationship between the various data, in accordance with the DBMS. 管理信息系统概要管理信息系统概要管理信息系统就是我们常说的MIS （Management Information System ），是一个由人、计算机等组成的能进行信息的收集、传送、储存、维护和使用的系统，在强调管理，强调信息的现代社会中它越来越得到普及。

计算机专业外文文献及翻译微软Visual Studio 微软 Visual Studio1 微软 Visual Studio Visual Studio 是微软公司推出的开发环境，Visual Studio 可以用来创建 Windows 平台下的Windows 应用程序和网络应用程序，也可以用来创建网络服务、智能设备应用程序和 Office 插件。

Visual Studio 是一个来自微软的集成开发环境 IDE(inteqrated development environment)，它可以用来开发由微软视窗，视窗手机，Windows CE、.NET 框架、.NET 精简框架和微软的 Silverlight 支持的控制台和图形用户界面的应用程序以及 Windows 窗体应用程序，网站，Web 应用程序和网络服务中的本地代码连同托管代码。

Visual Studio 包含一个由智能感知和代码重构支持的代码编辑器。

集成的调试工作既作为一个源代码级调试器又可以作为一台机器级调试器。

其他内置工具包括一个窗体设计的 GUI 应用程序，网页设计师，类设计师，数据库架构设计师。

它有几乎各个层面的插件增强功能，包括增加对支持源代码控制系统(如 Subversion 和 Visual SourceSafe)并添加新的工具集设计和可视化编辑器，如特定于域的语言或用于其他方面的软件开发生命周期的工具(例如 Team Foundation Server 的客户端:团队资源管理器)。

Visual Studio 支持不同的编程语言的服务方式的语言，它允许代码编辑器和调试器(在不同程度上)支持几乎所有的编程语言，提供了一个语言特定服务的存在。

内置的语言中包括 C/C 中(通过Visual C)(通过 Visual )，C,中(通过 Visual C,)和 F,(作为Visual Studio2010)，为支持其他语言，如 MPython和 Ruby 等，可通过安装单独的语言服务。

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

计算机毕设英文参考文献当涉及到毕业设计或者毕业论文的参考文献时，你可以考虑以下一些经典的计算机科学领域的文献：1. D. E. Knuth, "The Art of Computer Programming," Addison-Wesley, 1968.2. A. Turing, "On Computable Numbers, with an Application to the Entscheidungsproblem," Proceedings of the London Mathematical Society, 1936.3. V. Bush, "As We May Think," The Atlantic Monthly, 1945.4. C. Shannon, "A Mathematical Theory of Communication," Bell System Technical Journal, 1948.5. E. W. Dijkstra, "Go To Statement Considered Harmful," Communications of the ACM, 1968.6. L. Lamport, "Time, Clocks, and the Ordering of Events in a Distributed System," Communications of the ACM, 1978.7. T. Berners-Lee, R. Cailliau, "WorldWideWeb: Proposal for a HyperText Project," 1990.8. S. Brin, L. Page, "The Anatomy of a Large-Scale Hypertextual Web Search Engine," Computer Networks and ISDN Systems, 1998.这些文献涵盖了计算机科学领域的一些经典工作，包括算法、计算理论、分布式系统、人机交互等方面的内容。

Introduction to DevelopmentTo overcome the performance and scalability problems that CGI brings, Microsoft developed a new way for developers to build scalable applications. This high performance alternative is called the Internet Server Application Programming Interface(ISAPI). Instead of housing functionality in executable files, ISAPI uses DLLs. Using DLLs instead of executable programs has some definite performance and scalability advantages The ISAPI extension could also be called with arguments that will allow a single ISAPI extension to perform multiple tasks. Just as in the CGI example, the directory must have execute permissions enabled, or the DLL will be downloaded to the client rather than run on the server. ISAPI extensions are typically used to process client requests and output a response as HTML, which is very similar to the way CGI programs are used.ISAPI filters perform a function that can’t be directly duplicated with CGI applications. ISAPI filters are never explicitly called; instead, they are called by IIS in response to certain events in the life of a request. The developer can request that an ISAPI filter be called whenever any of the following events occur:1．When the server has preprocessed the client headers2．When the server authenticates the client3．When the server is mapping a logical URL to a physical URL4．Before raw data is sent from the client to the server5．After raw data is sent from the client to the server but before the server processes it 6．When the server logs information7．When the session is endingAs with any filter, ISAPI filters should request only the notifications it requires and process them as quickly as possible. One of the more common uses of ISAPI filters is to provide custom authentication. Another use is to modify the HTML that will be sent to the client. For example, an ISAPI filter could be used to change the background color of each page. Because ISAPI filters aren’t nearly as common as ISAPI extensions, I won’t cover them any further in this book. If you want to learn more about ISAPI extensions, you can check out my book Inside Server-Based Applications (Microsoft Press, 1999).ISAPI specifies several entry-point functions that must be exported from the DLL. Using these entry points, IIS can load the DLL; call the functions that it implements, passing in parameters as required; and receive the data to write back to the browser. ISAPI requires only two entry-point functions to be implemented these entry points, IIS can load the DLL;call the functions that it implements, passing in parameters as required; and receive the data to write back to the browser. ISAPI requires only two entry-point functions to be implementedA Better Solution: Active Server PagesIf you’re wondering why we’ve dwelt on th e alternatives to in a book about programming , the answer lies in the details of the implementation of and its predecessor, Active Server Pages (ASP). Understanding ISAPI is required for adept understanding of ASP and thus .During the beta of IIS 2.0, which became part of Windows NT 4.0, Microsoft introduced a new technology initially codenamed “Denali.” This was during Microsoft’s “Active” period and so the technology was eventually named Active Server Pages, or ASP. Several versions of have been released, most notably the versions included with Windows NT 4.0 Option Pack (ASP 2.0 and IIS 4.0) and Windows 2000 (ASP 3.0 and IIS 5.0). For the purposes of this discussion, I’ll consider ASP as a whole, without referring t o version differences became an instant hit, in large part because it made something that was difficult(create dynamic Web content) relatively easy. Creating CGI applications and ISAPI applications wasn’t terribly difficult, but using ASP was much simpler By default, ASP uses VBScript. Literally millions of developers are at least somewhat familiar with Visual Basic, Visual Basic for Applications (VBA), or VBScript. For these developers, ASP was the way to enter the Internet age. Certainly the developers could have learned a new programming language, but they didn’t have to with ASP. Partly because of its use of VBScript, ASP became a viable way to build Web applications.Just as important was the relatively easy access to databases allowed through Microsoft ActiveX Data Objects (ADO). When you need to generate dynamic content, that dynamic content obviously needs to come from somewhere, and ADO made it easy to get at that data.Finally, and perhaps most important, the development model allowed developers to essentially write code and run it. There was no need to perform compilation or elaborate installation steps. the architects were careful to capture this same development model, even though what’s going on under the covers is quite a bit different.A New Solution: When version 3.0 of was released along with Windows 2000, it became clearer that the future of software development was closely tied to the future of the Web. As part of its .NET initiative, Microsoft has introduced , a new version of ASP that retains the model of development ASP developers have come to know and love: youcan create the code and place it in the correct directory with the proper permissions, and it will just work. also introduces innovations that allow easier separation of the development of the core of an application and its presentation. adds many features to and enhances many of the capabilities in classic isn’t merely an incremental improvement to ASP; it’s really a completely new product, albeit a new product designed to allow the same development experience that ASP developers have enjoyed. Here are some of the notable features of : .NET Framework: The .NET Framework is an architecture that makes it easier to design Web and traditional applications.Common language runtime: The common language runtime provides a set of services for all languages. If you’re an ASP developer who has had to combine ASP scripting with COM objects, you’ll apprecia te the beauty of a common set of types across many languages.Compiled languages: provides enhanced performance through the use of compiled languages. Compiled languages allow the developer to verify that code is at least syntactically correct. ASP doesn’t provide any such facility, so simple syntax errors might not be caught until the first time the code is executed.Cool new languages Visual Basic: .NET is a completely new version of Visual Basic that provides a new, cleaner syntax. C# is a new language designed to look and feel a lot like C++, but without some of the unsafe features that make C++ difficult to use to create reliable applications. These two languages are available out of the box, but other languages will be available from third parties as well. As of this writing, COBOL and Eiffel implementations should be available for Visual Studio .NET as well.Visual Studio .NET: Visual Studio .NET is a cool new development environment that brings rapid application development (RAD) to the server.Improved components: The .NET Framework supports the use of new types of components that can be conveniently replaced in a running application.Web Forms: Web Forms allow Visual Basic–like development, with event handlers for common HTML widgets.XML Web services: XML Web services enable developers to create services and then make them available using industry standard protocols.: ADO for the .NET Framework is a new version of the technology that allows applications to more conveniently get at data residing in relational databases and in other formats, such as Extensible Markup Language (XML.) ConclusionThis brief history of Web development should provide you with a foundation as youcontinue reading about . Learning a programming language or development environment is much like learning a human language. Although books that cover the syntax and vocabulary are helpful, it’s often just as useful to understand the history of the people who use the language.If you’re an develope r, much of this chapter might be a review for you, but I hope that you’ve added something to your understanding of the history of . If you’re new to ASP and , understanding the history of ASP and what came before it will be useful as you begin to explore the exciting new technologies that make up .About Active Server Aside from the burden is not only (ASP) version of the next; It also provides a unified Web development models, including the development of enterprise-class Web applications generated personnel for the various services. grammar largely compatible with ASP, it also provides a new programming model and structure, flexibility and stability can produce better applications, and to provide better security protection. Through the existing ASP applications, gradually add functions to enhance ASP applications functions.When building applications, developers can use Web or XML Web services, or in any manner they deemed appropriate portfolio. Each functional access to the same support structure, so that you can use as a certification program, buffer frequently used data, or configuration of applications for self definition, only listed a few possibilities here.You can use Web-based generation of powerful the Web page. These generated pages, can be used to build public complaints server UI elements, and programming for the implementation of their common task. You can use these complaints to the building or from reusable components generated Web definition, thus simplifying the code page. For more information, please see Web pages. XML Web services provide a means of remote access server functions. Use XML Web services, enterprises can open data or business logic programming interface, and client-server applications and can acquire and operate these programming interfaces. Through the use of information such as web and XML standards such as the transmission of data across mobile firewall, XML Web services to customers - in-server or server-server programmed for data exchange. XML Web services without relying on specific components or technology transfer targets agreed. Therefore, the use of any language, using any component model, operating system and in any operating procedures can visit XML Web services. and. Net Framework version 1.1 installed, as each part of the Windows Server 2003 series products. You can add it through the control panels for the newprocedures, or use "of your server guide" opening it. In addition, according to this theme later introduced "with Windows XP Professional or Windows 2000 Server computer installed " process downloading 1.0. Installed Visual Studio. Net will also install 1.0.Use "of your server guide," in the operation of the Windows Server 2003 server installed .In the mission column, hit "start" button and then hit the "management of your servers," in the "management of your servers" window, hit "Add or remove players."In the "configuration of your server guide", hit the "next step" in the "server roles", selected "application servers (IIS, )," and then hit "next". "applications server option", hit the "opening " of, hit the "next" and then hit "next". If necessary, inserted in CD-ROM drive Windows Server 2003 installation CD, and then hit the "next step." Installation completed, hit the "completion."The use of "add / delete process" in operating the Windows Server 2003 server installed . In the mission column, hit "start" button, pointing to "control panels" and then hit the "add or delete procedures." "Windows components guides," "components" box, hit the "application server" of, then hit the "next step." When the "Windows components guides" configuration End Windows Server 2003, hit the "completion."In Windows Server 2003 series products in China by opening Server ManagementColumn in the mission, hit "start" button and then hit the "operation." In the "operation open" box, the importation and then hit "determined." ."Server management machine", a "local computer" and then hit "Web service expansion." Panes right, hit "" and then hit "allowed." state then changed to "allow".In operation running Windows XP Professional or Windows 2000 computer, download and install . If necessary, install and start IIS. On the installation, please refer to the operating system files. At /downloads/default.asp, a "Software Development Kits" (software development kits), hit the "Microsoft. net Framework SDK, "and then read the page on the SDK download requests, notes and choice. Hit for download option, and read the end-user licensing agreements, and then hit the "yes" (is). "document downloaded", download options to preserve documents, the choice to install procedures and documents downloaded to personal tale of folder, and then hit the "preservation". Check up on the latest personal tale of any document. Download documents located in the folder, Net Framework installation procedures Setup.exe.If you have IIS installed and activated, the installation of and. Net Framework, deployed applications and requests a page, but received one of the followingerror message, indicating the Web site has not been for the establishment of an appropriate authority or directory :"C:\Inetpub\Wwwroot" catalogue visit was denied. Failure to start monitoring directory changes. Server applications to visit catalogue "C:\Inetpub\Wwwroot\ Virtual Directory Name \". The catalogue does not exist or could not be visited for security establishment.At root Web site or any virtual directory, needs account (Aspnet_wp.exe process account) the retrieval, delivery and set limits. These must be installed, can visit the contents of documents and surveillance document changes. Requests the Executive next steps corrected the problem.Web site or virtual directory in the root of adding account retrieval, delivery and competence listedIn Windows resources management devices, to browse Web sites containing roots(acquiescence to the establishment of : C:\Inetpub\Wwwroot) or the virtual directory folder. In the "safe" choice card, hit "Add". Import Computer Name \ASPNET (for example, in the computer named Web imported Web\ASPNET), and then hit "determined." Allow account the following date: retrieval and implementation, a folder content, retrieval. Attention if the "Everyone" (Everyone) group or "users" group to retrieve root Web site or virtual directory, there would be no need to implement these steps.In Windows 2003 domain controller server, applications to network service identity operation (nothing to do with IIS isolation mode). In some cases, the domain controller function request to take additional steps to make your normal installation. 1.1 operating in the domain controller on the issue of the potential problems more information, Please see Microsoft knowledge base article Q824308 "IWAM Account is Not Granted the Impersonate Privilege for 1.1 on Windows 2000 Domain Controller with SP4" (SP4 installed in the Windows 2000 domain controller, not to IWAM account for 1.1 simulation Privileges), Web site knowledge base for . In the domain controller function. Net Framework 1.0 more information, Please see Microsoft knowledge base article Q315158, " Does Not Work with the Default Account on a Domain Controller" (with the domain controller, not the acquiescence account work), Web site knowledge base for .Author: ouglas J. TomFrom: Microsoft Applications微软设计应用因特网服务器应用程式介面：CGI具有扩充性能和克服的问题的能力，是微软公司开发的一种新的方式开发建设规模的应用。

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

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

术语联机和脱机通常分别用于描述连接于和没有连接于计算机的设备。

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

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

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

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

通过重新定位的读/写磁头，不同的同心圆磁道可以被访问。

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

在一个磁盘中，所有的磁头是一起移动的。

因此，当磁头移动到新的位置时，新的一组磁道可以存取了。

每一组磁道称为一个柱面。

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

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

（所以，盘片中心的储存的二进制位的密度要比靠近盘片边缘的大）。

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

磁区大小一般是不超过几个KB; 512 个字节或1024 个字节。

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

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

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

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

关于计算机的英文文献以下是一些关于计算机的英文文献：1. "Computer Science: The Discipline" by David Gries and Fred B. Schneider, published in 1993 in the journal Communications of the ACM.2. "The Art of Computer Programming" by Donald E. Knuth, published in three volumes between 1968 and 1973.3. "A Mathematical Theory of Communication" by Claude Shannon, published in 1948 in the Bell System Technical Journal.4. "Operating Systems Design and Implementation" by Andrew S. Tanenbaum and Albert S. Woodhull, published in 1997.5. "The Structure and Interpretation of Computer Programs" by Harold Abelson and Gerald Jay Sussman, published in 1984.6. "Computer Networks" by Andrew S. Tanenbaum, published in 1981.7. "Introduction to Algorithms" by Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and Clifford Stein, published in 1990.8. "Foundations of Computer Science" by Alfred Aho and Jeffrey Ullman, published in 1992.9. "Computer Architecture: A Quantitative Approach" byJohn L. Hennessy and David A. Patterson, first published in 1990.10. "Artificial Intelligence: A Modern Approach" by Stuart Russell and Peter Norvig, first published in 1995.。

计算机专业相关外文文献IntroductionComputer science is a field of study that deals with the theory, design, and application of computers. The field is continuously growing and evolving as new technologies are developed and innovative applications arise. As a result, scholarly literature is essential in keeping up-to-date with the latest trends and developments within the field. This article will provide a comprehensive review of recent academic literature related to computer science.Review of Literature1. Artificial IntelligenceThe field of artificial intelligence (AI) has experienced significant growth in recent years. In their study, “Deep Learning for Computer Vision: A Brief Review,” Chen et al. (2018) provide an overview of deep learning algorithms usedfor object recognition and image classification. Additionally, Kostoulas et al. (2018) analyze the role that AI can play in supporting knowledge management within organizations.2. Computer NetworksComputer networks continue to be a crucial component of communication and data transfer. In his study, “An Overviewof Emerging Wireless Networking Technologies,” Rajamani (2018) provides an overview of emerging wireless networking technologies and their potential applications. Furthermore,Breugel et al. (2018) examine the use of blockchaintechnology for data management in decentralized wireless networks.3. CybersecurityGiven the increasing number of cybersecurity threats,research related to this area has been growing. In their study, “A Survey of Recen t Advancements in Malware Detection Techniques,” Khan et al. (2019) provide an overview ofrecent research focused on malware detection techniques. Alternatively, Mayorga et al. (2018) explore the importanceof training users in preventing cyber-attacks.4. Human-Computer InteractionHuman-computer interaction (HCI) is an interdisciplinaryfield focused on the design and usability of computer systems. In their study, “Twenty Years of CHI: A Bibliometric Overview,” Maldonado et al. (2019) provide an analysi s ofthe development of HCI research during the past two decades. alternatively, Zhou et al. (2018) explore the use of gamification techniques to increase user engagement in online education systems.5. Big DataAs a consequence of the rapid growth in the volume and complexity of data sets, the development of big data-related technologies has gained traction. In their study, “A Comprehensive Study on Big Data Analytics,” Singh et al. (2019) provide an overview of big data analytics technologies and applications. Furthermore, Nisar et al. (2018) explorethe use of machine learning algorithms to improve big datastorage and retrieval systems.ConclusionThis review provides a comprehensive overview of recent academic literature on various topics relevant to computer science. From the review, it is clear that developments in AI, computer networks, cybersecurity, HCI, and big data have the potential to transform various industries. As such, keepingup-to-date with the latest research can help professionals remain abreast of the latest trends and developments in the computer science field.。

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

design resources can be organized in n with design activities。

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

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

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

This XXX。

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

It poses tasks into smaller subtasks。

XXX management of all design resources and activities。

TMS assigns resources to task nodes。

XXX。

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

In a net-based collaborative design environment。

n XXX n for all design resources and activities。

Progress in ComputersPrestige Lecture delivered to IEE, Cambridge, on 5 February 2004Maurice WilkesComputer LaboratoryUniversity of CambridgeThe first stored program computers began to work around 1950. The one we built in Cambridge, the EDSAC was first used in the summer of 1949.These early experimental computers were built by people like myself with varying backgrounds. We all had extensive experience in electronic engineering and were confident that that experience would stand us in good stead. This proved true, although we had some new things to learn. The most important of these was that transients must be treated correctly; what would cause a harmless flash on the screen of a television set could lead to a serious error in a computer.As far as computing circuits were concerned, we found ourselves with an embarass de richess. For example, we could use vacuum tube diodes for gates as we did in the EDSAC or pentodes with control signals on both grids, a system widely used elsewhere. This sort of choice persisted and the term families of logic came into use. Those who have worked in the computer field will remember TTL, ECL and CMOS. Of these, CMOS has now become dominant.In those early years, the IEE was still dominated by power engineering and we had to fight a number of major battles in order to get radio engineering along with the rapidly developing subject of electronics.dubbed in the IEE light current electrical engineering.properly recognised as an activity in its own right. I remember that we had some difficulty in organising a conference because the power engineers’ ways of doing things were not our ways. A minor source of irritation was that all IEE published papers were expected to start with a lengthy statement of earlier practice, something difficult to do when there was no earlier practiceConsolidation in the 1960sBy the late 50s or early 1960s, the heroic pioneering stage was over and the computer field was starting up in real earnest. The number of computersin the world had increased and they were much more reliable than the very early ones . To those years we can ascribe the first steps in high level languages and the first operating systems. Experimental time-sharing was beginning, and ultimately computer graphics was to come along.Above all, transistors began to replace vacuum tubes. This change presented a formidable challenge to the engineers of the day. They had to forget what they knew about circuits and start again. It can only be said that they measured up superbly well to the challenge and that the change could not have gone more smoothly.Soon it was found possible to put more than one transistor on the same bit of silicon, and this was the beginning of integrated circuits. As time went on, a sufficient level of integration was reached for one chip to accommodate enough transistors for a small number of gates or flip flops. This led to a range of chips known as the 7400 series. The gates and flip flops were independent of one another and each had its own pins. They could be connected by off-chip wiring to make a computer or anything else.These chips made a new kind of computer possible. It was called a minicomputer. It was something less that a mainframe, but still very powerful, and much more affordable. Instead of having one expensive mainframe for the whole organisation, a business or a university was able to have a minicomputer for each major department.Before long minicomputers began to spread and become more powerful. The world was hungry for computing power and it had been very frustrating for industry not to be able to supply it on the scale required and at a reasonable cost. Minicomputers transformed the situation.The fall in the cost of computing did not start with the minicomputer; it had always been that way. This was what I meant when I referred in my abstract to inflation in the computer industry ‘going the other way’. As time goes on people get more for their money, not less.Research in Computer Hardware.The time that I am describing was a wonderful one for research in computer hardware. The user of the 7400 series could work at the gate and flip-flop level and yet the overall level of integration was sufficient to give a degree of reliability far above that of discreet transistors. The researcher, in auniversity or elsewhere, could build any digital device that a fertile imagination could conjure up. In the Computer Laboratory we built the Cambridge CAP, a full-scale minicomputer with fancy capability logic.The 7400 series was still going strong in the mid 1970s and was used for the Cambridge Ring, a pioneering wide-band local area network. Publication of the design study for the Ring came just before the announcement of the Ethernet. Until these two systems appeared, users had mostly been content with teletype-based local area networks.Rings need high reliability because, as the pulses go repeatedly round the ring, they must be continually amplified and regenerated. It was the high reliability provided by the 7400 series of chips that gave us the courage needed to embark on the project for the Cambridge Ring.The RISC Movement and Its AftermathEarly computers had simple instruction sets. As time went on designers of commercially available machines added additional features which they thought would improve performance. Few comparative measurements were done and on the whole the choice of features depended upon the designer’s intuition.In 1980, the RISC movement that was to change all this broke on the world. The movement opened with a paper by Patterson and Ditzel entitled The Case for the Reduced Instructions Set Computer.Apart from leading to a striking acronym, this title conveys little of the insights into instruction set design which went with the RISC movement, in particular the way it facilitated pipelining, a system whereby several instructions may be in different stages of execution within the processor at the same time. Pipelining was not new, but it was new for small computers The RISC movement benefited greatly from methods which had recently become available for estimating the performance to be expected from a computer design without actually implementing it. I refer to the use of a powerful existing computer to simulate the new design. By the use of simulation, RISC advocates were able to predict with some confidence that a good RISC design would be able to out-perform the best conventional computers using the same circuit technology. This prediction was ultimately born out in practice.Simulation made rapid progress and soon came into universal use by computer designers. In consequence, computer design has become more of ascience and less of an art. Today, designers expect to have a roomful of, computers available to do their simulations, not just one. They refer to such a roomful by the attractive name of computer farm.The x86 Instruction SetLittle is now heard of pre-RISC instruction sets with one major exception, namely that of the Intel 8086 and its progeny, collectively referred to as x86. This has become the dominant instruction set and the RISC instruction sets that originally had a considerable measure of success are having to put up a hard fight for survival.This dominance of x86 disappoints people like myself who come from the research wings.both academic and industrial.of the computer field. No doubt, business considerations have a lot to do with the survival of x86, but there are other reasons as well. However much we research oriented people would like to think otherwise. high level languages have not yet eliminated the use of machine code altogether. We need to keep reminding ourselves that there is much to be said for strict binary compatibility with previous usage when that can be attained. Nevertheless, things might have been different if Intel’s major attempt to produ ce a good RISC chip had been more successful.I am referring to the i860 (not the i960, which was something different). In many ways the i860 was an excellent chip, but its software interface did not fit it to be used in a workstation.There is an interesting sting in the tail of this apparently easy triumph of the x86 instruction set. It proved impossible to match the steadily increasing speed of RISC processors by direct implementation of the x86 instruction set as had been done in the past. Instead, designers took a leaf out of the RISC book; although it is not obvious, on the surface, a modern x86 processor chip contains hidden within it a RISC-style processor with its own internal RISC coding. The incoming x86 code is, after suitable massaging, converted into this internal code and handed over to the RISC processor where the critical execution is performed.In this summing up of the RISC movement, I rely heavily on the latest edition of Hennessy and Patterson’s books on computer design as my supporting authority; see in particular Computer Architecture, third edition, 2003, pp 146, 151-4, 157-8.The IA-64 instruction set.Some time ago, Intel and Hewlett-Packard introduced the IA-64instruction set. This was primarily intended to meet a generally recognised need for a 64 bit address space. In this, it followed the lead of the designers of the MIPS R4000 and Alpha. However one would have thought that Intel would have stressed compatibility with the x86; the puzzle is that they did the exact opposite.Moreover, built into the design of IA-64 is a feature known as predication which makes it incompatible in a major way with all other instruction sets. In particular, it needs 6 extra bits with each instruction. This upsets the traditional balance between instruction word length and information content, and it changes significantly the brief of the compiler writer.In spite of having an entirely new instruction set, Intel made the puzzling claim that chips based on IA-64 would be compatible with earlierx86 chips. It was hard to see exactly what was meant.Chips for the latest IA-64 processor, namely, the Itanium, appear to have special hardware for compatibility. Even so, x86 code runs very slowly.Because of the above complications, implementation of IA-64 requires a larger chip than is required for more conventional instruction sets. This in turn implies a higher cost. Such at any rate, is the received wisdom, and, as a general principle, it was repeated as such by Gordon Moore when he visited Cambridge recently to open the Betty and Gordon Moore Library. I have, however, heard it said that the matter appears differently from within Intel. This I do not understand. But I am very ready to admit that I am completely out of my depth as regards the economics of the semiconductor industry.AMD have defined a 64 bit instruction set that is more compatible with x86 and they appear to be making headway with it. The chip is not a particularly large one. Some people think that this is what Intel should have done. [Since the lecture was delivered, Intel have announced that they will market a range of chips essentially compatible with those offered by AMD.] The Relentless Drive towards Smaller TransistorsThe scale of integration continued to increase. This was achieved by shrinking the original transistors so that more could be put on a chip. Moreover, the laws of physics were on the side of the manufacturers. The transistors also got faster, simply by getting smaller. It was therefore possible to have, at the same time, both high density and high speed.There was a further advantage. Chips are made on discs of silicon,known as wafers. Each wafer has on it a large number of individual chips, which are processed together and later separated. Since shrinkage makes it possible to get more chips on a wafer, the cost per chip goes down.Falling unit cost was important to the industry because, if the latest chips are cheaper to make as well as faster, there is no reason to go on offering the old ones, at least not indefinitely. There can thus be one product for the entire market.However, detailed cost calculations showed that, in order to maintain this advantage as shrinkage proceeded beyond a certain point, it would be necessary to move to larger wafers. The increase in the size of wafers was no small matter. Originally, wafers were one or two inches in diameter, and by 2000 they were as much as twelve inches. At first, it puzzled me that, when shrinkage presented so many other problems, the industry should make things harder for itself by going to larger wafers. I now see that reducing unit cost was just as important to the industry as increasing the number of transistors on a chip, and that this justified the additional investment in foundries and the increased risk.The degree of integration is measured by the feature size, which, for a given technology, is best defined as the half the distance between wires in the densest chips made in that technology. At the present time, production of 90 nm chips is still building upSuspension of LawIn March 1997, Gordon Moore was a guest speaker at the celebrations of the centenary of the discovery of the electron held at the Cavendish Laboratory. It was during the course of his lecture that I first heard the fact that you can have silicon chips that are both fast and low in cost described as a violation of Murphy’s law.or Sod’s law as it is usually called in the UK. Moore said that experience in other fields would lead you to expect to have to choose between speed and cost, or to compromise between them. In fact, in the case of silicon chips, it is possible to have both.In a reference book available on the web, Murphy is identified as an engineer working on human acceleration tests for the US Air Force in 1949. However, we were perfectly familiar with the law in my student days, when we called it by a much more prosaic name than either of those mentioned above, namely, the Law of General Cussedness. We even had a mock examination question in which the law featured. It was the type of question inwhich the first part asks for a definition of some law or principle and the second part contains a problem to be solved with the aid of it. In our case the first part was to define the Law of General Cussedness and the second was the problem;A cyclist sets out on a circular cycling tour. Derive an equation giving the direction of the wind at any time.The single-chip computerAt each shrinkage the number of chips was reduced and there were fewer wires going from one chip to another. This led to an additional increment in overall speed, since the transmission of signals from one chip to another takes a long time.Eventually, shrinkage proceeded to the point at which the whole processor except for the caches could be put on one chip. This enabled a workstation to be built that out-performed the fastest minicomputer of the day, and the result was to kill the minicomputer stone dead. As we all know, this had severe consequences for the computer industry and for the people working in it.From the above time the high density CMOS silicon chip was Cock of the Roost. Shrinkage went on until millions of transistors could be put on a single chip and the speed went up in proportion.Processor designers began to experiment with new architectural features designed to give extra speed. One very successful experiment concerned methods for predicting the way program branches would go. It was a surprise to me how successful this was. It led to a significant speeding up of program execution and other forms of prediction followedEqually surprising is what it has been found possible to put on a single chip computer by way of advanced features. For example, features that had been developed for the IBM Model 91.the giant computer at the top of the System 360 range.are now to be found on microcomputersMurphy’s Law remained in a state of suspension. No longer did it make sense to build experimental computers out of chips with a small scale of integration, such as that provided by the 7400 series. People who wanted to do hardware research at the circuit level had no option but to design chips and seek for ways to get them made. For a time, this was possible, if not easy Unfortunately, there has since been a dramatic increase in the cost of making chips, mainly because of the increased cost of making masks for lithography, a photographic process used in the manufacture of chips. It has,in consequence, again become very difficult to finance the making of research chips, and this is a currently cause for some concern.The Semiconductor Road MapThe extensive research and development work underlying the above advances has been made possible by a remarkable cooperative effort on the part of the international semiconductor industry.At one time US monopoly laws would probably have made it illegal for US companies to participate in such an effort. However about 1980 significant and far reaching changes took place in the laws. The concept of pre-competitive research was introduced. Companies can now collaborate at the pre-competitive stage and later go on to develop products of their own in the regular competitive manner.The agent by which the pre-competitive research in the semi-conductor industry is managed is known as the Semiconductor Industry Association (SIA). This has been active as a US organisation since 1992 and it became international in 1998. Membership is open to any organisation that can contribute to the research effort.Every two years SIA produces a new version of a document known as the International Technological Roadmap for Semiconductors (ITRS), with an update in the intermediate years. The first volume bearing the title‘Roadmap’ was issued in 1994 but two reports, written in 1992 and distributed in 1993, are regarded as the true beginning of the series.Successive roadmaps aim at providing the best available industrial consensus on the way that the industry should move forward. They set out in great detail.over a 15 year horizon. the targets that must be achieved if the number of components on a chip is to be doubled every eighteen months.that is, if Moore’s law is to be maintained.-and if the cost per chip is to fall.In the case of some items, the way ahead is clear. In others, manufacturing problems are foreseen and solutions to them are known, although not yet fully worked out; these areas are coloured yellow in the tables. Areas for which problems are foreseen, but for which no manufacturable solutions are known, are coloured red. Red areas are referred to as Red Brick Walls.The targets set out in the Roadmaps have proved realistic as well as challenging, and the progress of the industry as a whole has followed the Roadmaps closely. This is a remarkable achievement and it may be said thatthe merits of cooperation and competition have been combined in an admirable manner.It is to be noted that the major strategic decisions affecting the progress of the industry have been taken at the pre-competitive level in relative openness, rather than behind closed doors. These include the progression to larger wafers.By 1995, I had begun to wonder exactly what would happen when the inevitable point was reached at which it became impossible to make transistors any smaller. My enquiries led me to visit ARPA headquarters in Washington DC, where I was given a copy of the recently produced Roadmap for 1994. This made it plain that serious problems would arise when a feature size of 100 nm was reached, an event projected to happen in 2007, with 70 nm following in 2010. The year for which the coming of 100 nm (or rather 90 nm) was projected was in later Roadmaps moved forward to 2004 and in the event the industry got there a little sooner.I presented the above information from the 1994 Roadmap, along with such other information that I could obtain, in a lecture to the IEE in London, entitled The CMOS end-point and related topics in Computing and delivered on 8 February 1996.The idea that I then had was that the end would be a direct consequence of the number of electrons available to represent a one being reduced from thousands to a few hundred. At this point statistical fluctuations would become troublesome, and thereafter the circuits would either fail to work, or if they did work would not be any faster. In fact the physical limitations that are now beginning to make themselves felt do not arise through shortage of electrons, but because the insulating layers on the chip have become so thin that leakage due to quantum mechanical tunnelling has become troublesome.There are many problems facing the chip manufacturer other than those that arise from fundamental physics, especially problems with lithography. In an update to the 2001 Roadmap published in 2002, it was stated that the continuation of progress at present rate will be at risk as we approach 2005 when the roadmap projects that progress will stall without researchbreak-throughs in most technical areas “. This was the most specific statement about the Red Brick Wall, that had so far come from the SIA and it was a strong one. The 2003 Roadmap reinforces this statement by showing many areas marked red, indicating the existence of problems for which nomanufacturable solutions are known.It is satisfactory to report that, so far, timely solutions have been foundto all the problems encountered. The Roadmap is a remarkable document and, for all its frankness about the problems looming above, it radiates immense confidence. Prevailing opinion reflects that confidence and there is a general expectation that, by one means or another, shrinkage will continue, perhaps down to 45 nm or even less.However, costs will rise steeply and at an increasing rate. It is cost that will ultimately be seen as the reason for calling a halt. The exact point at which an industrial consensus is reached that the escalating costs can no longer be met will depend on the general economic climate as well as on the financial strength of the semiconductor industry itself.。

Modern design and manufacturingCAD/CAMCAD/CAM is a term which means computer-aided design and computer-aided manufacturing. It is the technology concerned with the use of digital computers to perform certain functions in design and production. This technology is moving in the direction of greater integration（一体化）of design and manufacturing, two activities which have traditionally been treated as distinct（清楚的）and separate functions in a production firm. Ultimately, CAD/CAM will provide the technology base for the computer-integrated factory of the future.Computer-aided design (CAD) can be defined as the use of computer systems to assist in the creation, modification, analysis, or optimization（最优化）of a design. The computer systems consist of the hardware and software to perform the specialized design functions required by the particular user firm. The CAD hardware typically includes the computer, one or more graphics display terminals, keyboards, and other peripheral equipment. The CAD software consists of the computer programs to implement（实现，执行）computer graphics to facilitate the engineering functions of the user company. Examples of these application programs include stress-strain （压力-应变）analysis of components（部件）, dynamic（动态的）response of mechanisms, heat-transfer calculations, and numerical control part programming. The collection of application programs will vary from one user firm to the next because their product lines, manufacturing processes, and customer markets are different these factors give rise to differences in CAD system requirements.Computer-aided manufacturing (CAM) can be defined as the use of computer systems to plan, manage, and control the operations of a manufacturing plant through either direct or indirect computer interface with the plant’s production resources. As indicated by the definition, the applications of computer-aided manufacturing fall into two broad categories:puter monitoring and control.2.manufacturing support applications.The distinction between the two categories is fundamental to an understanding of computer-aided manufacturing.In addition to the applications involving a direct computer-process interface （界面，接口）for the purpose of process monitoring and control, compute-aided manufacturing also includes indirect applications in which the computer serves a support role in the manufacturing operations of the plant. In these applications, the computer is not linked directly to the manufacturing process. Instead, the computer is used “off-line”（脱机）to provide plans, schedules, forecasts, instructions, and information by which the firm’s production resources can be managed more effectively. The form of the relationship between the computer and the process is represented symbolically in the figure given below. Dashed lines（虚线）are used to indicate that the communication and control link is an off-line connection, with human beings often required to consummate（使圆满）the interface. However, human beings are presently required in the application either to provide input to the computer programs or to interpret the computer output and implement the required action.CAM for manufacturing supportWhat is CAD/CAM software?Many toolpaths are simply too difficult and expensive to program manually. For these situations, we need the help of a computer to write an NC part program.The fundamental concept of CAD/CAM is that we can use a Computer-Aided Drafting (CAD) system to draw the geometry of a workpiece on a computer. Once the geometry is completed, then we can use a computer-Aided Manufacturing (CAM) system to generate an NC toolpath based on the CAD geometry.The progression（行进，级数）from a CAD drawing all the way to the working NC code is illustrated as follows:Step 1: The geometry is defined in a CAD drawing. This workpiece contains a pocket to be machined. It might take several hours to manually write the code for this pocket（凹槽，型腔）. However, we can use a CAM program to create the NC code in a matter of minutes.Step 2: The model is next imported into the CAM module. We can then select the proper geometry and define the style of toolpath to create, which in this case is a pocket. We must also tell the CAM system which tools to use, the type of material, feed, and depth of cut information.Step 3: The CAM model is then verified to ensure that the toolpaths are correct. If any mistakes are found, it is simple to make changes at this point.Step 4: The final product of CAD/CAM process is the NC code. The NC code is produced by post-processing（后处理）the model, the code is customized（定制，用户化）to accommodate the particular variety of CNC control.Another acronym that we may run into is CAPP, which stands for Computer-Aided Part Programming. CAPP is the process of using computers to aid in the programming of NC toolpaths. However, the acronym CAPP never really gained widespread acceptance, and today we seldom hear this term. Instead, the more marketable CAD/CAM is used to express the idea of using computers to help generate NC part programs. This is unfortunate because CAM is an entire group of technologies related to manufacturing design and automation-not just the software that is used to program CNC machine tools.Description of CAD/CAM Components and FunctionsCAD/CAM systems contain both CAD and CAM capabilities – each of which has a number of functional elements. It will help to take a short look at some of these elements in order to understand the entire process.1. CAD ModuleThe CAD portion of the system is used to create the geometry as a CAD model. The CAD model is an electronic description of the workpiece geometry that is mathematically precise. The CAD system, whether stand alone or as part of a CAD/CAM package, tends to be available in several different levels of sophistication. （强词夺理，混合）2-D line drawings 两维线条图Geometry is represented in two axes, much like drawing on a sheet of paper. Z-level depths will have to be added on the CAM end.3-D wireframe models 三维线框模型Geometry is represented in three-dimensional space by connecting elements that represent edges and boundaries. Wiregrames can be difficult to visualize（想象，形象化，显现）, but all Z axis information is available for the CAM operations.3-D surface models 三维表面模型These are similar to wireframes except that a thin skin has been stretched over the wireframe model to aid in visualization.Inside, the model is empty. Complex contoured Surfaces are possible with surface models.3-D solid modeling 三维实体模型This is the current state of the market technology that is used by all high-end software. The geometry is represented as a solid feature that contains mass. Solid models can be sliced（切片，部分，片段）open to reveal internal features and not just a thin skin.2. CAM ModuleThe CAM module is used to create the machining process model based upon the geometry supplied in the CAD model. For example, the CAD model may contain a feature that we recognize as a pocket .We could apply a pocketing routine to the geometry, and then all of the toolpaths would be automatically created to produce thepocket. Likewise, the CAD model（模子，铸型）may contain geometry that should be produced with drilling operations. We can simply select the geometry and instruct the CAM system to drill holes at the selected locations.The CAM system will generate a generic（一般的，普通的）intermediate （中间的，媒介）code that describes the machining operations, which can later be used to produce G & M code or conversational programs. Some systems create intermediate code in their own proprietary（所有的，私人拥有的）language, which others use open standards such as APT for their intermediate files.The CAM modules also come in several classes and levels of sophistication. First, there is usually a different module available for milling, turning, wire EDM, and fabrication（装配）. Each of the processes is unique enough that the modules are typically sold as add-ins（附加软件）. Each module may also be available with different levels of capability. For example, CAM modules for milling are often broken into stages as follows, starting with very simple capabilities and ending with complex, multi-axis toolpaths :● 21/2-axis machining● Three-axis machining with fourth-axis positioning● Surface machining● Simultaneous five-axis machiningEach of these represents a higher level of capability that may not be needed in all manufacturing environments. A job shop might only require 3-axis capability. An aerospace contractor might need a sophisticated 5-axis CAM package that is capable of complex machining. This class of software might start at $5,000 per installation, but the most sophisticated modules can cost $15,000 or more. Therefore, there is no need to buy software at such a high level that we will not be able to use it to its full potential.3.Geometry vs. toolpathOne important concept we must understand is that the geometry represented by the CAD drawing may not be exactly the same geometry that is produced on the CNC machine C machine tools are equipped to produce very accurate toolpaths aslong as the toolpaths are either straight lines or circular arcs. CAD systems are also capable of producing highly accurate geometry of straight line and circular arcs, but they can also produce a number of other classes of curves. Most often these curves are represented as Non-Uniform（不均匀的，不一致的）Rational Bezier Splines (NURBS) （非均匀有理B样条）. NURBS curves can represent virtually any geometry, ranging from a straight line or circular arc to complex surfaces.Take, for example, the geometric entity that we call an ellipse（椭圆形）. An ellipse is a class of curve that is mathematically different from a circular arc. An ellipse is easily produced on a CAD system with the click of the mouse. However, a standard CNC machine tool cannot be use to directly problem an ellipse – it can only create lines and circular arcs. The CAM system will reconcile（使和解，使顺从）this problem by estimating the curve with line segments.CNC machine tools usually only understand circular arcs or straight lines. Therefore, the CAM system must estimate curved surfaces with line segments. The curve in this illustration is that of an ellipse, and the toolpath generated consists of tangent line segments that are contained within a tolerance zone.The CAM system will generate a bounding geometry on either side of the true curve to form a tolerance zone.It will then produce a toolpath from the line segment that stays contained within the tolerance zone. The resulting toolpath will not be mathematically correct – the CAM system will only be able to estimate the surface. This basic method is used to produce estimated toolpaths for both 2-D curves and 3-D surface curves.Some CAM programs also have the ability to convert the line segments into arc segments. This can reduce the number of blocks in the program and lead to smoother surfaces.The programmer can control the size of the tolerance zone to create a toolpath that is as accurate as is needed. Smaller tolerance zones will produce finer toolpaths and more numerous line segments, while larger tolerance zones will produce fewer line segments and coarser（粗糙的）toolpaths. Each line segment will require a block of code in the NC program, so the NC part program can grow very large whenusing this technique.We must use caution when machining surfaces. It is easy to rely on the computer to generate the correct tooolpath, but finished surfaces are further estimated during machining with ball end mills.If we do not pay attention to the limitations of these techniques, then the accuracy of the finished workpiece may be compromised （妥协，折衷）.4.Tool and material librariesTo create the machining operations, the CAM system will need to know which cutting tools are available and what material we are machining. CAM systems take care of this by providing customizable （可定制的）libraries of cutting tools and materials. Tool libraries contain information about the shape and style of the tool. Material libraries contain information that is used to optimize（使最优化）the cutting speeds and feeds. The CAM system uses this information together to create the correct toolpaths and machining parameters.（参数）The format of these tool and material libraries is often proprietary（专利的，独占的，私有的）and can present some portability issues.Proprietary（轻便，移动）tool and material files cannot be easily modified or used on another system. More progressive （改革论者，进步论者，前进的）CAM developers tend to produce their tool and material libraries as database files that can be easily modified and customized for other applications.5.Verification and post-processorCAM systems usually provide the ability to verify that the proposed toolpaths are correct. This can be via a simple backplot（背景绘制）of the tool centerline or via a sophisticated solid model of the machining operations. The solids verifications（确认，查证）is often a third-party software that the CAD/CAM software company has licensed.（得到许可的）However, it may be available as a standalone package. The post-processor is a software program that takes a generic intermediate code and formats the NC code for each particular machine tool control. The post-processor（后置处理器）can often be customized through templates（模板）and variables toprovide the required customization. （用户化，专用化，定制）6.Portability 轻便，可带的Portability of electronic data is the Achilles` heel(唯一致命的弱点)of CAD/CAM systems and continues to be a time-consuming concern. CAD files are created in a number of formats and have to be shared between many organizations. It is very expensive to create a complex model on a CAD system; therefore, we want to maximize the portability of our models and minimize the need for recreating the geometry on another system.DXF, DWG, IGES, SAT, STL and parasolids are a few of the common formats for CAD data exchange.CAM process models are not nearly as portable as CAD models. We cannot usually take a CAM model developed in one system and transfer it to another platform. The only widely accepted standard for CAM model interchange is a version of Automatically Programmed Tool (APT). APT is a programming language used to describe machining operations. APT is an open standard that is well documented and can be accessed by third-party software developers. A number of CAD/CAM systems can export to this standard, and the CAM file can later be used by post-processors and verification software.There are some circumstances when the proprietary intermediate files created by certain CAD/CAM systems can be fed directly into a machine tool without any additional post-processing. This is an ideal solution, but there is not currently any standard governing this exchange.One other option for XAD/CAM model exchange is to use a reverse post-processor. A reverse post-processor can create a CAD/CAM model from a G &M-code of NC part program. These programs do work; however, the programmer must spend a considerable amount of time determining the design intent of the model and to separate the toolpaths from the geometry. Overall, reverse post-processing has very limited applications.Software issues and trendsThroughout industry, numerous software packages are used for CAD and CAD/CAM. Pure CAD systems are used in all areas of design, and virtually any product today is designed With CAD software-gone are the days of pencil and paper drawings.CAD/CAM software, on the other hand, is more specialized. CAD/CAM is a small but important niche（适当的位置）confined to machining and fabrication organizations, and it is found in much smaller numbers than its CAD big brother.CAD/CAM systems contain both the software for CAD design and the CAM software for creating toolpaths and NC code. However, the CAD portion is often weak and unrefined when compared to much of the leading pure CAD software. This mismatch sets up the classic（第一流的，标准的）argument between the CAD designers and the CAD/CAM programmer on what is the best way to approach CAD/CAM.A great argument can be made for creating all geometry on an industry-leading CAD system and then importing the geometry into a CAD/CAM system.A business is much better off if its engineers only have to create a CAD model one time and in one format. The geometry can then be imported into the CAD/CAM package for process modeling. Furthermore, industry-leading CAD software tends to set an unofficial standard. The greater the acceptance of the standard, the greater the return on investment for the businesses that own the software.The counter argument comes from small organizations that do not have the need or resources to own both an expensive, industry-standard CAD package and an expensive CAD/CAM package. They tend to have to redraw the geometry from the paper engineering drawing or import models with imperfect（有缺点的，未完成的）translators. Any original models will end up being stored as highly non-standardized CAD/CAM files. These models will have dubious（可疑的，不确定的）prospects（景色，前景，期望）of ever being translated to a more standardized version.Regardless of the path that is chosen, organizations and individuals tend to become entrenched（以壕沟防护）in a particular technology. If they have invested tremendous effort and time into learning and assimilating（吸收）a technology, then it becomes very difficult to change to a new technology, even when presented with overwhelming（压倒性的，无法抵抗的）evidence of a better method. It can be quite painful to change. Of course, if we had a crystal ball and could see into the future, this would never happen; but the fact is that we cannot always predict what the dominant（有统治权的，占优势的）technology will be even a few years down the road.The result is technology entrenchment（堑墩）that can be very difficult and expensive to get out from under. About the only protection we can find is to select the technology that appears to be the most standardized (even if it is imperfect) and stay with it-then, if major changes appear down the road, we will be in a better position to adapt.。

NET-BASED TASK MANAGEMENT SYSTEMHector Garcia-Molina, Jeffrey D. Ullman, Jennifer WisdomABSTRACTIn net-based collaborative design environment, design resources become more and more varied and complex. Besides common information management systems, design resources can be organized in connection with design activities.A set of activities and resources linked by logic relations can form a task. A task has at least one objective and can be broken down into smaller ones. So a design project can be separated into many subtasks forming a hierarchical structure.Task Management System (TMS) is designed to break down these tasks and assign certain resources to its task nodes．As a result of decomposition.al1 design resources and activities could be managed via this system.KEY WORDS：Collaborative Design, Task Management System (TMS), Task Decomposition, Information Management System1 IntroductionAlong with the rapid upgrade of request for advanced design methods, more and more design tool appeared to support new design methods and forms. Design in a web environment with multi-partners being involved requires a more powerful and efficient management system .Design partners can be located everywhere over the net with their own organizations. They could be mutually independent experts or teams of tens of employees. This article discusses a task management system (TMS) which manages design activities and resources by breaking down design objectives and re-organizing design resources in connection with the activities. Comparing with common information management systems (IMS) like product data management system and document management system, TMS can manage the whole design process. It has two tiers which make it much more f1exible in structure.The 1ower tier consists of traditional common IMSS and the upper one fulfillslogic activity management through controlling a tree-like structure, allocating design resources and making decisions about how to carry out a design project. Its functioning paradigm varies in differe nt projects depending on the project’s scale and purpose. As a result of this structure, TMS can separate its data model from its logic mode1.It could bring about structure optimization and efficiency improvement, especially in a large scale project.2 Task Management in Net-Based Collaborative Design Environment2.1 Evolution of the Design EnvironmentDuring a net-based collaborative design process, designers transform their working environment from a single PC desktop to LAN, and even extend to WAN. Each design partner can be a single expert or a combination of many teams of several subjects, even if they are far away from each other geographically. In the net-based collaborative design environment, people from every terminal of the net can exchange their information interactively with each other and send data to authorized roles via their design tools. The Co Design Space is such an environment which provides a set of these tools to help design partners communicate and obtain design information. Code sign Space aims at improving the efficiency of collaborative work, making enterprises increase its sensitivity to markets and optimize the configuration of resource.2.2 Management of Resources and Activities in Net-Based Collaborative EnvironmentThe expansion of design environment also caused a new problem of how to organize the resources and design activities in that environment. As the number of design partners increases, resources also increase in direct proportion. But relations between resources increase in square ratio. To organize these resources and their relations needs an integrated management system which can recognize them and provide to designers in case of they are needed.One solution is to use special information management system (IMS).An IMS can provide database, file systems and in/out interfaces to manage a given resource. Forexample there are several IMS tools in Co Design Space such as Product Data Management System, Document Management System and so on. These systems can provide its special information which design users want.But the structure of design activities is much more complicated than these IM S could manage, because even a simple design project may involve different design resources such as documents, drafts and equipments. Not only product data or documents, design activities also need the support of organizations in design processes. This article puts forward a new design system which attempts to integrate different resources into the related design activities. That is task management system (TMS).3 Task Breakdown Model3.1 Basis of Task BreakdownWhen people set out to accomplish a project, they usually separate it into a sequence of tasks and finish them one by one. Each design project can be regarded as an aggregate of activities, roles and data. Here we define a task as a set of activities and resources and also having at least one objective. Because large tasks can be separated into small ones, if we separate a project target into several lower—level objectives, we define that the project is broken down into subtasks and each objective maps to a subtask. Obviously if each subtask is accomplished, the project is surely finished. So TMS integrates design activities and resources through planning these tasks.Net-based collaborative design mostly aims at products development. Project managers (PM) assign subtasks to designers or design teams who may locate in other cities. The designers and teams execute their own tasks under the constraints which are defined by the PM and negotiated with each other via the collaborative design environment. So the designers and teams are independent collaborative partners and have incompact coupling relationships. They are driven together only by theft design tasks. After the PM have finished decomposing the project, each designer or team leader who has been assigned with a subtask become a 1ow-class PM of his own task. And he can do the same thing as his PM done to him, re-breaking down and re-assigning tasks.So we put forward two rules for Task Breakdown in a net-based environment, incompact coupling and object-driven. Incompact coupling means the less relationshipbetween two tasks. When two subtasks were coupled too tightly, the requirement for communication between their designers will increase a lot. Too much communication wil1 not only waste time and reduce efficiency, but also bring errors. It will become much more difficult to manage project process than usually in this situation. On the other hand every task has its own objective. From the view point of PM of a superior task each subtask could be a black box and how to execute these subtasks is unknown. The PM concerns only the results and constraints of these subtasks, and may never concern what will happen inside it.3.2 Task Breakdown MethodAccording to the above basis, a project can be separated into several subtasks. And when this separating continues, it will finally be decomposed into a task tree. Except the root of the tree is a project, all eaves and branches are subtasks. Since a design project can be separated into a task tree, all its resources can be added to it depending on their relationship. For example, a Small-Sized-Satellite.Design (3SD) project can be broken down into two design objectives as Satellite Hardware. Design (SHD) and Satellite-Software-Exploit (SSE). And it also has two teams. Design team A and design team B which we regard as design resources. When A is assigned to SSE and B to SHD. We break down the project as shown in Fig 1.It is alike to manage other resources in a project in this way. So when we define a collaborative design project’s task model, we should first claim the project’s targets. These targets include functional goals, performance goals, and quality goals and so on. Then we could confirm how to execute this project. Next we can go on to break down it. The project can be separated into two or more subtasks since there are at 1east two partners in a collaborative project. Either we could separate the project into stepwise tasks, which have time sequence relationships in case of some more complex projects and then break down the stepwise tasks according to their phase-to-phase goals.There is also another trouble in executing a task breakdown. When a task is broken into severa1 subtasks; it is not merely “a simple sum motion” of other tasks. In most cases their subtasks could have more complex relations.To solve this problem we use constraints. There are time sequence constraint (TSC) and logic constraint (LC). The time sequence constraint defines the time relationships among subtasks. The TSC has four different types, FF, FS, SF and SS. Fmeans finish and S presents start. If we say Tabb is FS and lag four days, it means Tb should start no later than four days after Ta is finished.The logic constraint is much more complicated. It defines logic relationship among multiple tasks.Here is given an example:“Task TA is separated into three subtasks, Ta, T b and Tc. But there are two more rules.Tb and Tc can not be executed until Ta is finished.Tb and Tc can not be executed both，that means if Tb was executed, Tc should not be executed, and vice versa. This depends on the result of Ta.”So we say Tb and Tc have a logic constraint. After finishing breaking down the tasks, we can get a task tree as Fig, 2 illustrates.4 TMS Realization4.1 TMS StructureAccording to our discussion about task tree model and task breakdown basis, we can develop a Task Management System (TMS) based on Co Design Space using Java language, JSP technology and Microsoft SQL 2000. The task management system’s structure is shown in Fig. 3.TMS has four main modules namely Task Breakdown, Role Management, Statistics and Query and Data Integration. The Task Breakdown module helps users to work out task tree. Role Management module performs authentication and authorization of access control. Statistics and Query module is an extra tool for users to find more information about their task. The last Data Integration Module provides in/out interface for TMS with its peripheral environment.4.2 Key Points in System Realization4.2.1 Integration with Co Design SpaceCo Design Space is an integrated information management system which stores, shares and processes design data and provides a series of tools to support users. These tools can share all information in the database because they have a universal DataMode1. Which is defined in an XML (extensible Markup Language) file, and has a hierarchical structure. Based on this XML structure the TMS h data mode1 definition is organized as following.<?xml version= 1.0 encoding= UTF-8’?><!--comment：Common Resource Definitions Above．The Followingare Task Design--><!ELEMENT ProductProcessResource (Prcses?, History?，AsBuiltProduct*，ItemsObj?, Changes?, ManufacturerParts?，SupplierParts?，AttachmentsObj? ，Contacts?，PartLibrary?，AdditionalAttributes*)><!ELEMENT Prcses (Prcs+) ><!ELEMENT Prcs (Prcses，PrcsNotes?，PrcsArc*，Contacts?，AdditionalAttributes*，Attachments?)><!ELEM ENT PrcsArc EMPTY><!ELEMENT PrcsNotes(PrcsNote*)><!ELEMENT PrcsNote EMPTY>Notes: Element “Pros” is a task node ob ject, and “Process” is a task set object which contains subtask objects and is belongs to a higher class task object. One task object can have no more than one “Presses” objects. According to this definition, “Prcs” objects are organized in a tree-formation process. The other objects are resources, such as task link object (“Presage”), task notes (“Pros Notes”), and task documents (“Attachments”) .These resources are shared in Co Design database.文章出处：计算机智能研究[J],47卷，2007：647-703基于网络的任务管理系统摘要在网络与设计协同化的环境下，设计资源变得越来越多样化和复杂化。

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

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

关于计算机的英文文献写作范文摘要全文共3篇示例，供读者参考篇1Title: A Study on the Impact of Computers on SocietyAbstract:Computers have become an integral part of modern society, with their influence pervading all aspects of human life. This study aims to explore the impact of computers on society, focusing on the social, economic, and cultural aspects. The research is based on a comprehensive review of existing literature and empirical studies that have investigated the relationship between computers and society.The study finds that computers have revolutionized communication and information exchange, leading to a more connected and globalized world. The internet, in particular, has transformed the way people interact, work, and socialize. The rise of social media and online platforms has created new channels for communication and expression, but also raised concerns about privacy and data security.Economically, computers have changed the nature of work and productivity, with automation and artificial intelligence increasingly taking over routine tasks. While this has led to increased efficiencies and innovation, it has also raised questions about job displacement and income inequality. The gig economy and freelance work are becoming more common, as people adapt to the changing landscape of labor.Culturally, computers have influenced the way people consume media, create art, and express themselves. Digital technologies have democratized access to information and creative tools, but also raised issues of authenticity and copyright. The prevalence of online platforms for entertainment and social interaction has reshaped cultural practices and norms.In conclusion, computers have had a profound impact on society, shaping the way people communicate, work, and think. While the benefits of technology are clear, it is important to consider the social and ethical implications of its widespread adoption. More research is needed to understand the long-term effects of computers on society and to ensure that technology serves the greater good.篇2Title: Writing a Research Paper on ComputersAbstract:This paper discusses the process of writing a research paper on computers. It provides a step-by-step guide on how to effectively research, organize, and write a paper on the topic of computers. The paper outlines the importance of choosing a specific research question, conducting thorough research, and citing sources properly. It also explains how to structure a research paper on computers, including the introduction, literature review, methodology, results, discussion, and conclusion sections. Additionally, the paper provides tips on how to write clearly and concisely, avoid plagiarism, and revise and edit the paper for clarity and coherence. Overall, this paper serves as a comprehensive guide for students and researchers looking to write a research paper on computers.篇3Title: A Study on Computer Science: Writing Research PapersAbstract:Computer science is a rapidly growing field with a wide array of topics and subfields for researchers to explore. Writing research papers in computer science requires a combination oftechnical expertise and strong writing skills. This paper provides an overview of the key components of a research paper in computer science, along with useful tips and strategies for successful writing.The first step in writing a research paper in computer science is to select a topic that is both interesting and relevant to current advancements in the field. The paper should clearly define the research question or problem to be addressed, along with the objectives and methodology of the study. It is important to review existing literature on the topic to ensure that the research is original and contributes to the existing body of knowledge.The next step is to organize the paper into logical sections, including an introduction, literature review, methodology, results, discussion, and conclusion. Each section should be clearly structured and well-written, with appropriate citations and references to support the claims made in the paper. It is important to use a clear and concise writing style, avoiding unnecessary jargon and technical terms that may confuse the reader.In addition to the technical content of the paper, the writing style and presentation are also important factors to consider. The paper should be well-organized, with a logical flow of ideas andarguments. Charts, tables, and figures can be used to illustrate key points and data, but should be used sparingly and effectively.Finally, the paper should be carefully proofread and edited to ensure that it is free of errors in grammar, punctuation, and spelling. It is also important to consider the formatting and citation style required by the target journal or conference. By following these guidelines and tips, researchers can improve the quality of their research papers in computer science and increase their chances of publication and impact in the field.。

外文文献Computer network virus and precautionsWith the new network technology and application of the continuous rapid development of the computer network should Use of becoming increasingly widespread, the role played by the increasingly important computer networks and human More inseparable from the lives of the community's reliance on them will keep growing. With the continuous development of computer technology, the virus has become increasingly complex and senior, the new generation of computer viruses make full use of certain commonly used operating systems and application software for protection of the weak low spots have rampant in recent years as the popularity of the Internet in the world, will be attached document containing the virus the situation in the mail has been increasing spread of the virus through the Internet, making the spread of the virus speed Sharp also increased, by an ever-increasing scope of the infection. Therefore, the protection of the security of computer networks will become increasingly important.First,a computer virusA computer virus the definition of computer virus computer virus (Computer Virus) in the "people's republic of China the computer information system security protection regulations "which has been clearly defined, the virus" refers to the preparation or computer program inserted in the damage or destruction of computer data functions, affecting computer use Self-replication and can a group of computer instructions, or code. "Second, network virusWith the development of network and the Internet, a wider spread, the greater New harm the virus emerged this is the Internet virus. The virus is an emerging concept in the traditional the virus was not classified network virus this concept, because the development of networks, the traditional virus the network also has a number of characteristics. Today's Internet virus is a broad notion of as a long as it is carried out using the Internet to spread destruction can be known as network viruses, such as: "Love the back door", "Panda burning incense."Third, network virus and the distinction between computer virusThe original common computer virus is nothing more than the devastating formatted hard drive, delete system with the users documents, databases,etc.destruction. The mode of transmission is through nothing but also by virus infection mutual copy of the software, carrying the virus, such as the use of pirated optical discs, such as infection disk systems the pilot virus and infected executable file virus, in addition to a network virus these are the common characteristics of the virus, but also steal users with remote data, remote control of the other side computers and other damaged properties, such as Trojan and consumption of funding the operationof the network computer source collapse of the network server worm.Fourth, the network against virusNetwork destructive virus, will directly affect the work of the network, ranging from lowering speed video ring for the efficiency of the network, while in the collapse, undermining the server information to a multi-year work destroyed Dan. Because viruses and other network annually fraud led to economic losses of over 16 billion yuan, But this figure is constantly rising year by year. The next few years, the size of the market will reach Security 60 billion yuan. One antivirus software experts pointed out: "Network avian flu virus even more." Such as: "Xiong Cat burning incense "In addition to virus infection through the web site users, the latest virus also through QQ Loopholes in propagating itself through file-sharing networks, the default sharing, weak password systems, U disk and windows forms bottom of the top mobile hard drives, and other means of communication. While LAN once a computer machine for infection, it can spread through the entire network instant, or even within a very short period of time can be infected thousands of computers, can lead to serious networks. Symptoms of poisoning in the performance of computers there are enforceable. Exe files have become a strange pattern, the pattern shown as "Panda Burning incense, "and then System blue screen, restart the frequent, hard drive data destruction, serious entire company all computer LAN will all poisoning. "Panda burning incense," only more than half a month, a few varieties have high of more than 50, and the number of its users infected constantly expanding. Makes infected, "Panda burn incense" disease the personal drug users has been as high as several million people infected with a few more corporate users is rising exponentially. Network more on the computer network the greater the harm caused by the virus.Fifth, Network transmission of the virus Features1. Infection fast: single machine environment, the virus can only be passed fromone computer diskette to another, and in the network can be adopted by the rapid spread of network communication mechanism. According to measurement set against a typical PC network use in normal circumstances, once a computer workstation sick drugs, and will be online within 10 minutes in the several hundreds of all infected computers.2. Proliferation of a wide range: in the network due to the spread of the virus very quickly and spread to encompass a large area, not only the rapid transmission of all LAN computer, but also through remote workstations virus in moment inter spread to thousands of miles away.3. Dissemination in the form of complex and varied: computer viruses in general through the network " Station server workstation "channels of communication, but in the form of complex and diverse communication.4. Difficult to completely wipe: the standalone computer virus carriers sometimes can be deleted documents or low-level formatted drives, and other measures to eliminate the virus completely, and the network once a computer work clean stations failed to disinfect the entire network can be re-infected by the virus, or even just completed removal the work of a workstation is likely to be on-line by another workstation virus infection. Therefore, Only workstations in addition to killing viruses, and can not solve the virus harm to the network is.中文译文计算机网络病毒与防范随着各种新的网络技术的不断应用和迅速发展, 计算机网络的应用范围变得越来越广泛, 所起的作用越来越重要, 计算机网络与人类的生活更加密不可分, 社会对其的依赖程度也会随之不断增长。