客户端编程（注释⑧）
Web 最初采用的“服务器－浏览器”方案可提供交互式内容，但这种交互能力完全由服务器提供，为服务器和因特网带来了不小的负担。服务器一般为客户浏览器产生静态网页，由后者简单地解释并显示出来。基本HTML 语言提供了简单的数据收集机制：文字输入框、复选框、单选钮、列表以及下拉列表等，另外还有一个按钮，只能由程序规定重新设置表单中的数据，以便回传给服务器。用户提交的信息通过所有Web 服务器均能支持的“通用网关接口”（CGI）回传到服务器。包含在提交数据中的文字指示CGI 该如何操作。最常见的行动是运行位于服务器的一个程序。那个程序一般保存在一个名为“cgi-bin”的目录中（按下Web 页内的一个按钮时，请注意一下浏览器顶部的地址窗，经常都能发现“cgi-bin”的字样）。大多数语言都可用来编制这些程序，但其中最常见的是Perl 。这是由于Perl 是专为文字的处理及解释而设计的，所以能在任何服务器上安装和使用，无论采用的处理器或操作系统是什么。
⑧：本节内容改编自某位作者的一篇文章。那篇文章最早出现在位于https://www.doczj.com/doc/b35676204.html, Mainspring上。本节的采用已征得了对方的同意。
今天的许多Web 站点都严格地建立在CGI 的基础上，事实上几乎所有事情都可用CGI 做到。唯一的问题就是响应时间。CGI 程序的响应取决于需要传送多少数据，以及服务器和因特网两方面的负担有多重（而且CGI程序的启动比较慢）。Web 的早期设计者并未预料到当初绰绰有余的带宽很快就变得不够用，这正是大量应用充斥网上造成的结果。例如，此时任何形式的动态图形显示都几乎不能连贯地显示，因为此时必须创建一个GIF 文件，再将图形的每种变化从服务器传递给客户。而且大家应该对输入表单上的数据校验有着深刻的体会。原来的方法是我们按下网页上的提交按钮（Submit）；数据回传给服务器；服务器启动一个CGI 程序，检查用户输入是否有错；格式化一个HTML 页，通知可能遇到的错误，并将这个页回传给我们；随后必须回到原先那个表单页，再输入一遍。这种方法不仅速度非常慢，也显得非常繁琐。解决的办法就是客户端的程序设计。运行Web 浏览器的大多数机器都拥有足够强的能力，可进行其他大量工作。与此同时，原始的静态HTML 方法仍然可以采用，它会一直等到服务器送回下一个页。客户端编程意味着Web 浏览器可获得更充分的利用，并可有效改善Web 服务器的交互（互动）能力。对客户端编程的讨论与常规编程问
题的讨论并没有太大的区别。采用的参数肯定是相同的，只是运行的平台不同：Web 浏览器就象一个有限的操作系统。无论如何，我们仍然需要编程，仍然会在客户端编程中遇到大量问题，同时也有很多解决的方案。在本节剩下的部分里，我们将对这些问题进行一番概括，并介绍在客户端编程中采取的对策。
1. 插件
朝客户端编程迈进的时候，最重要的一个问题就是插件的设计。利用插件，程序员可以方便地为浏览器添加新功能，用户只需下载一些代码，把它们“插入”浏览器的适当位置即可。这些代码的作用是告诉浏览器“从现在开始，你可以进行这些新活动了”（仅需下载这些插入一次）。有些快速和功能强大的行为是通过插件添加到浏览器的。但插件的编写并不是一件简单的任务。在我们构建一个特定的站点时，可能并不希望涉及这方面的工作。对客户端程序设计来说，插件的价值在于它允许专业程序员设计出一种新的语言，并将那种语言添加到浏览器，同时不必经过浏览器原创者的许可。由此可以看出，插件实际是浏览器的一个“后门”，允许创建新的客户端程序设计语言（尽管并非所有语言都是作为插件实现的）。
2. 脚本编制语言
插件造成了脚本编制语言的爆炸性增长。通过这种脚本语言，可将用于自己客户端程序的源码直接插入HTML页，而对那种语言进行解释的插件会在HTML 页显示的时候自动激活。脚本语言一般都倾向于尽量简化，易于理解。而且由于它们是从属于HTML 页的一些简单正文，所以只需向服务器发出对那个页的一次请求，即可非常快地载入。缺点是我们的代码全部暴露在人们面前。另一方面，由于通常不用脚本编制语言做过份复杂的事情，所以这个问题暂且可以放在一边。脚本语言真正面向的是特定类型问题的解决，其中主要涉及如何创建更丰富、更具有互动能力的图形用户界面（GUI）。然而，脚本语言也许能解决客户端编程中80％的问题。你碰到的问题可能完全就在那80％里面。而且由于脚本编制语言的宗旨是尽可能地简化与快速，所以在考虑其他更复杂的方案之前（如Java 及ActiveX），首先应想一下脚本语言是否可行。目前讨论得最多的脚本编制语言包括JavaScript（它与Java 没有任何关系；之所以叫那个名字，完全是一种市场策略）、VBScript（同Visual Basic 很相似）以
及Tcl/Tk（来源于流行的跨平台GUI 构造语言）。当然还有其他许多语言，也有许多正在开发JavaScript 也许是目前常用的，它得到的支持也最全面。无论NetscapeNavigator，Microsoft Internet Explorer，还是Opera，目前都提供了对JavaScript 的支持。除此以外，市面上讲述JavaScript 的书籍也要比讲述其他语言的书多得多。有些工具还能利用JavaScript 自动产生网页。当然，如果你已经有VisualBasic 或者Tcl/Tk 的深厚功底，当然用它们要简单得多，起码可以避免学习新语言的烦恼（解决Web 方面的问题就已经够让人头痛了）。
3. Java
如果说一种脚本编制语言能解决80％的客户端程序设计问题，那么剩下的20％又该怎么办呢？它们属于一些高难度的问题吗？目前最流行的方案就是Java。它不仅是一种功能强大、高度安全、可以跨平台使用以及国际通用的程序设计语言，也是一种具有旺盛生命力的语言。对Java 的扩展是不断进行的，提供的语言特性和库能够很好地解决传统语言不能解决的问题，比如多线程操作、数据库访问、连网程序设计以及分布式计算等等。Java 通过“程序片”（Applet）巧妙地解决了客户端编程的问题。程序片（或“小应用程序”）是一种非常小的程序，只能在Web 浏览器中运行。作为Web 页的一部分，程序片代码会自动下载回来（这和网页中的图片差不多）。激活程序片后，它会执行一个程序。程序片的一个优点体现在：通过程序片，一旦用户需要客户软件，软件就可从服务器自动下载回来。它们能自动取得客户软件的最新版本，不会出错，也没有重新安装的麻烦。由于Java 的设计原理，程序员只需要创建程序的一个版本，那个程序能在几乎所有计算机以及安装了Java 解释器的浏览器中运行。由于Java 是一种全功能的编程语言，所以在向服务器发出一个请求之前，我们能先在客户端做完尽可能多的工作。例如，再也不必通过因特网传送一个请求表单，再由服务器确定其中是否存在一个拼写或者其他参数错误。大多数数据校验工作均可在客户端完成，没有必要坐在计算机前面焦急地等待服务器的响应。这样一来，不仅速度和响应的灵敏度得到了极大的提高，对网络和服务器造成的负担也可以明显减轻，这对保障因特网的畅通是至关重要的。与脚本程序相比，Java 程序片的另一个优点是它采用编译好的形式，所以客户端看不到源码。当然在另一方面，反编译Java 程序片也并不是件难事，而且代码的隐藏一般并不是个重要的问题。大家要注意另外
两个重要的问题。正如本书以前讲到的那样，编译好的Java 程序片可能包含了许多模块，所以要多次“命中”（访问）服务器以便下载（在Java 1.1 中，这个问题得到了有效的改善——利用Java 压缩档，即JAR 文件——它允许设计者将所有必要的模块都封装到一起，供用户统一下载）。在另一方面，脚本程序是作为Web 页正文的一部分集成到Web 页内的。这种程序一般都非常小，可有效减少对服务器的点击数。另一个因素是学习方面的问题。不管你平时听别人怎么说，Java 都不是一种十分容易便可学会的语言。如果你以前是一名Visual Basic 程序员，那么转向VBScript 会是一种最快捷的方案。由于VBScript 可以解决大多数典型的客户机／服务器问题，所以一旦上手，就很难下定决心再去学习Java。如果对脚本编制语言比较熟，那么在转向Java 之前，建议先熟悉一下JavaScript 或者VBScript，因为它们可能已经能够满足你的需要，不必经历学习Java 的艰苦过程。
Client-side programming
The Web’s initial server-browser design provided for interactive content, but the
interactivity was completely provided by the server. The server produced static pages for the client browser, which would simply interpret and display them. Basic HyperText Markup Language (HTML) contains simple mechanisms for data gathering: text-entry boxes, check boxes, radio boxes, lists and dropdown lists, as well as a button that could only be programmed to reset the data on the form or “submit” the data on the form back to the server. This submission passes through the Common Gateway Interface (CGI) provided on all Web servers. The text within the submission tells CGI what to do with it. The most common action is to run a program located on the server in a directory that’s typically called “cgi-bin.” (If you watch the address window at the top of your browser when you push a button on a Web page, you can sometimes see “cgi-bin” within all the gobbledygook there.) These programs can be written in most languages. Perl has been a common choice because it is designed for text manipulation and is interpreted, so it can be installed on any server regardless of processor or operating system. However, Python (https://www.doczj.com/doc/b35676204.html,) has been making inroads because of its greater power and simplicity.
Many powerful Web sites today are built strictly on CGI, and you can in fact do nearly anything with CGI. However, Web sites built on CGI programs can rapidly become overly complicated to maintain, and there is also the problem of response time. The response of a CGI program depends on how much data must be sent, as well as the load on both the server and the Internet. (On top of this, starting a CGI program tends to be slow.) The initial
designers of the Web did not foresee how rapidly this bandwidth would be exhausted for the kinds of applications people developed. For example, any sort of dynamic graphing is nearly impossible to perform with consistency because a Graphics Interchange Format (GIF) file must be created and moved from the server to the client for each version of the graph. In addition, you’ve no doubt experienced the process of data validation for a Web input form. You press the submit button on a page; the data is shipped back to the server; the server starts a CGI program that discovers an error, formats an HTML page informing you of the error, and then sends the page back to you; you must then back up a page and try again. Not only is this slow, it’s inelegant.
The solution is client-side programming. Most desktop computers that run Web browsers are powerful engines capable of doing vast work, and with the original static HTML approach they are sitting there, just idly waiting for the server to dish up the next page. Client-side programming means that the Web browser is harnessed to do whatever work it can, and the result for the user is a much speedier and more interactive experience at your Web site.
The problem with discussions of client-side programming is that they aren’t very different from discussions of programming in general. The parameters are almost the same, but the platform is different; a Web browser is like a limited operating system. In the end, you must still program, and this accounts for the dizzying array of problems and solutions produced by client-side programming. The rest of this section provides an overview of the issues and approaches in client-side programming.
Plug-ins
One of the most significant steps forward in client-side programming is the development of the plug-in. This is a way for a programmer to add new functionality to the browser by downloading a piece of code that plugs itself into the appropriate spot in the browser. It tells the browser, “From now on you can perform this new activity.” (You need to download the plug-in only once.) Some fast and powerful behavior is added to browsers via plug-ins, but writing a plug-in is not a trivial task, and isn’t something you’d want to do as part of the process of building a particular site. The value of the plug-in for client-side programming is that it allows an expert programmer to develop extensions and add those extensions to a browser without the permission of the browser manufacturer. Thus, plug-ins provide a “back door” that allows the creation of new client-side programming languages (although not all languages are implemented as plug-ins).
Scripting languages
Plug-ins resulted in the development of browser scripting languages. With a scripting language, you embed the source code for your client-side program directly into the HTML page, and the plug-in that interprets that language is automatically activated while the HTML page is being displayed. Scripting languages tend to be reasonably easy to understand and, because they are simply text that is part of an HTML page, they load very quickly as part of the single server hit required to procure that page. The trade-off is that your code is exposed for everyone to see (and steal). Generally, however, you aren’t doing amazingly sophisticated things with scripting languages, so this is not too much of a hardship.
One scripting language that you can expect a Web browser to support without a plug-in is JavaScript (this has only a passing resemblance to Java and you’ll have to climb an additional learning curve to use it. It was named that way just to grab some of Java’s marketing momentum). Unfortunately, most Web browsers originally implemented JavaScript in a different way from the other Web browsers, and even from other versions of
themselves. The standardization of JavaScript in the form of ECMAScript has helped, but it has taken a long time for the various browsers to catch up (and it didn’t help that Microsoft was pushing its own agenda in the form of VBScript, which also had vague similarities to JavaScript). In general, you must program in a kind of least-common-denominator form of JavaScript in
order to be able to run on all browsers. Dealing with errors and debugging JavaScript can only be described as a mess. As proof of its difficulty, only recently has anyone created a truly complex piece of JavaScript (Google, in GMail), and that required excessive dedication and expertise.
This points out that the scripting languages used inside Web browsers are really intended to solve specific types of problems, primarily the creation of richer and more interactive graphical user interfaces (GUIs). However, a scripting language might solve 80 percent of the problems encountered in client-side programming. Your problems might very well fit completely within that 80 percent, and since scripting languages can allow easier and faster development, you should probably consider a scripting language before looking at a more involved solution such as Java programming.
Java
If a scripting language can solve 80 percent of the client-side programming problems, what about the other 20 percent—the “really hard stuff”? Java is a popular solution for this. Not only is it a powerful programming language built to be secure, cross-platform, and international, but Java is being continually extended to provide language features and libraries that elegantly handle problems that are difficult in traditional programming languages, such as concurrency, database access, network programming, and distributed computing. Java allows client-side programming via the applet and with Java Web Start.
An applet is a mini-program that will run only under a Web browser. The applet is downloaded automatically as part of a Web page (just as, for example, a graphic is automatically downloaded). When the applet is activated, it executes a program. This is part of its beauty—it provides you with a way to automatically distribute the client
software from the server at the time the user needs the client software, and no sooner. The user gets the latest version of the client software without fail and without difficult reinstallation. Because of the way Java is designed, the programmer needs to create only a single program, and that program automatically works with all computers that have browsers with built-in Java interpreters. (This safely includes the vast majority of machines.) Since Java is a full-fledged programming language, you can do as much work as possible on the client before and after making requests of the server. For example, you won’t need to send a request form across the Internet to discover that you’ve gotten a date or some other parameter wrong, and your client computer can quickly do the work of plotting data instead of waiting for the server to make a plot and ship a graphic image back to you. Not only do you get the immediate win of speed and responsiveness, but the general network traffic and load on servers can be reduced, preventing the entire Internet from slowing down.
外文翻译 专业机械设计制造及其自动化学生姓名刘链柱 班级机制111 学号1110101102 指导教师葛友华
外文资料名称： Design and performance evaluation of vacuum cleaners using cyclone technology 外文资料出处：Korean J. Chem. Eng., 23(6), (用外文写) 925-930 (2006) 附件： 1.外文资料翻译译文 2.外文原文
应用旋风技术真空吸尘器的设计和性能介绍 吉尔泰金，洪城铱昌，宰瑾李， 刘链柱译 摘要：旋风型分离器技术用于真空吸尘器 - 轴向进流旋风和切向进气道流旋风有效地收集粉尘和降低压力降已被实验研究。优化设计等因素作为集尘效率，压降，并切成尺寸被粒度对应于分级收集的50％的效率进行了研究。颗粒切成大小降低入口面积，体直径，减小涡取景器直径的旋风。切向入口的双流量气旋具有良好的性能考虑的350毫米汞柱的低压降和为1.5μm的质量中位直径在1米3的流量的截止尺寸。一使用切向入口的双流量旋风吸尘器示出了势是一种有效的方法，用于收集在家庭中产生的粉尘。 摘要及关键词：吸尘器; 粉尘; 旋风分离器 引言 我们这个时代的很大一部分都花在了房子，工作场所，或其他建筑，因此，室内空间应该是既舒适情绪和卫生。但室内空气中含有超过室外空气因气密性的二次污染物，毒物，食品气味。这是通过使用产生在建筑中的新材料和设备。真空吸尘器为代表的家电去除有害物质从地板到地毯所用的商用真空吸尘器房子由纸过滤，预过滤器和排气过滤器通过洁净的空气排放到大气中。虽然真空吸尘器是方便在使用中，吸入压力下降说唱空转成比例地清洗的时间，以及纸过滤器也应定期更换，由于压力下降，气味和细菌通过纸过滤器内的残留粉尘。 图1示出了大气气溶胶的粒度分布通常是双峰形，在粗颗粒（>2.0微米）模式为主要的外部来源，如风吹尘，海盐喷雾，火山，从工厂直接排放和车辆废气排放，以及那些在细颗粒模式包括燃烧或光化学反应。表1显示模式，典型的大气航空的直径和质量浓度溶胶被许多研究者测量。精细模式在0.18?0.36 在5.7到25微米尺寸范围微米尺寸范围。质量浓度为2?205微克，可直接在大气气溶胶和 3.85至36.3μg/m3柴油气溶胶。
农村社会养老保险的现状、问题与对策研究社会保障对国家安定和经济发展具有重要作用，“城乡二元经济”现象日益凸现，农村社会保障问题客观上成为社会保障体系中极为重要的部分。建立和完善农村社会保障制度关系到农村乃至整个社会的经济发展，并且对我国和谐社会的构建至关重要。我国农村社会保障制度尚不完善，因此有必要加强对农村独立社会保障制度的构建，尤其对农村养老制度的改革，建立健全我国社会保障体系。从户籍制度上看，我国居民养老问题可分为城市居民养老和农村居民养老两部分。对于城市居民我国政府已有比较充足的政策与资金投人，使他们在物质和精神方面都能得到较好地照顾，基本实现了社会化养老。而农村居民的养老问题却日益突出，成为摆在我国政府面前的一个紧迫而又棘手的问题。 一、我国农村社会养老保险的现状 关于农村养老，许多地区还没有建立农村社会养老体系，已建立的地区也存在很多缺陷，运行中出现了很多问题，所以完善农村社会养老保险体系的必要性与紧迫性日益体现出来。 （一）人口老龄化加快 随着城市化步伐的加快和农村劳动力的输出，越来越多的农村青壮年人口进入城市，年龄结构出现“两头大，中间小”的局面。中国农村进入老龄社会的步伐日渐加快。第五次人口普查显示：中国65岁以上的人中农村为5938万，占老龄总人口的67.4%.在这种严峻的现实面前，农村社会养老保险的徘徊显得极其不协调。 （二）农村社会养老保险覆盖面太小 中国拥有世界上数量最多的老年人口，且大多在农村。据统计，未纳入社会保障的农村人口还很多，截止2000年底，全国7400多万农村居民参加了保险，占全部农村居民的11.18%，占成年农村居民的11.59%.另外，据国家统计局统计，我国进城务工者已从改革开放之初的不到200万人增加到2003年的1.14亿人。而基本方案中没有体现出对留在农村的农民和进城务工的农民给予区别对待。进城务工的农民既没被纳入到农村养老保险体系中，也没被纳入到城市养老保险体系中，处于法律保护的空白地带。所以很有必要考虑这个特殊群体的养老保险问题。
Inventory management Inventory Control On the so-called "inventory control", many people will interpret it as a "storage management", which is actually a big distortion. The traditional narrow view, mainly for warehouse inventory control of materials for inventory, data processing, storage, distribution, etc., through the implementation of anti-corrosion, temperature and humidity control means, to make the custody of the physical inventory to maintain optimum purposes. This is just a form of inventory control, or can be defined as the physical inventory control. How, then, from a broad perspective to understand inventory control? Inventory control should be related to the company's financial and operational objectives, in particular operating cash flow by optimizing the entire demand and supply chain management processes (DSCM), a reasonable set of ERP control strategy, and supported by appropriate information processing tools, tools to achieved in ensuring the timely delivery of the premise, as far as possible to reduce inventory levels, reducing inventory and obsolescence, the risk of devaluation. In this sense, the physical inventory control to achieve financial goals is just a means to control the entire inventory or just a necessary part; from the perspective of organizational functions, physical inventory control, warehouse management is mainly the responsibility of The broad inventory control is the demand and supply chain management, and the whole company's responsibility. Why until now many people's understanding of inventory control, limited physical inventory control? The following two reasons can not be ignored: First, our enterprises do not attach importance to inventory control. Especially those who benefit relatively good business, as long as there is money on the few people to consider the problem of inventory turnover. Inventory control is simply interpreted as warehouse management, unless the time to spend money, it may have been to see the inventory problem, and see the results are often very simple procurement to buy more, or did not do warehouse departments . Second, ERP misleading. Invoicing software is simple audacity to call it ERP, companies on their so-called ERP can reduce the number of inventory, inventory control, seems to rely on their small software can get. Even as SAP, BAAN ERP world, the field of
Advantages of Managed Code Microsoft intermediate language shares with Java byte code the idea that it is a low-level language witha simple syntax , which can be very quickly translated intonative machine code. Having this well-defined universal syntax for code has significant advantages. Platform independence First, it means that the same file containing byte code instructions can be placed on any platform; atruntime the final stage of compilation can then be easily accomplished so that the code will run on thatparticular platform. In other words, by compiling to IL we obtain platform independence for .NET, inmuch the same way as compiling to Java byte code gives Java platform independence. Performance improvement IL is actually a bit more ambitious than Java bytecode. IL is always Just-In-Time compiled (known as JIT), whereas Java byte code was ofteninterpreted. One of the disadvantages of Java was that, on execution, the process of translating from Javabyte code to native executable resulted in a loss of performance. Instead of compiling the entire application in one go (which could lead to a slow start-up time), the JITcompiler simply compiles each portion of code as it is called (just-in-time). When code has been compiled.once, the resultant native executable is stored until the application exits, so that it does not need to berecompiled the next time that portion of code is run. Microsoft argues that this process is more efficientthan compiling the entire application code at the start, because of the likelihood that large portions of anyapplication code will not actually be executed in any given run. Using the JIT compiler, such code willnever be compiled.
英文翻译说明 1. 英文翻译文章输成word，5号新罗马（New Times Roman）字体，1.5倍行间距，将来方便打印和一起装订；英文中的图表要重新画，禁止截图。 2. 整篇论文1.5倍行间距，打印时，用B5纸，版面上空2.5cm，下空2cm，左空2.5cm，右空2cm（左装订）。 3. 论文翻译后的摘要用五号宋体，正文小四号宋体、英文和数字用新罗马（New Times Roman）12、参考文献的内容用五号字体。图和表头用五号字体加粗并居中，图和表中的内容用五号字体。论文翻译的作者用五号字体加粗。 论文大标题………小三号黑体、加黑、居中 第二层次的题序和标题………小四号黑体、加黑、居中 第三层次的题序和标题………小四号宋体、加黑、居中 正文……………………………小四号宋体、英文用新罗马12 页码……………………………小五号居中，页码两边不加修饰符 4. 论文中参考文献严格按照下述排版。 专著格式：序号.编著者.书名[M].出版地: 出版社, 年代, 起止页码 期刊论文格式：序号.作者.论文名称[J]. 期刊名称, 年度, 卷(期): 起止页码 学位论文格式：序号.作者.学位论文名称[D]. 发表地: 学位授予单位, 年度 例子: (1).胡千庭, 邹银辉, 文光才等. 瓦斯含量法预测突出危险新技术[J]. 煤炭学报, 2007.32(3): 276-280. (2). 胡千庭. 煤与瓦斯突出的力学作用机理及应用研究[D]. 北京: 中国矿业大学(北京), 2007. (3). 程伟. 煤与瓦斯突出危险性预测及防治技术[M]. 徐州: 中国矿业大学出版社, 2003.
软件专业毕业论文外文文献中英文翻译 Object landscapes and lifetimes Tech nically, OOP is just about abstract data typing, in herita nee, and polymorphism, but other issues can be at least as importa nt. The rema in der of this sect ion will cover these issues. One of the most importa nt factors is the way objects are created and destroyed. Where is the data for an object and how is the lifetime of the object con trolled? There are differe nt philosophies at work here. C++ takes the approach that con trol of efficie ncy is the most importa nt issue, so it gives the programmer a choice. For maximum run-time speed, the storage and lifetime can be determined while the program is being written, by placing the objects on the stack (these are sometimes called automatic or scoped variables) or in the static storage area. This places a priority on the speed of storage allocatio n and release, and con trol of these can be very valuable in some situati ons. However, you sacrifice flexibility because you must know the exact qua ntity, lifetime, and type of objects while you're writing the program. If you are trying to solve a more general problem such as computer-aided desig n, warehouse man ageme nt, or air-traffic con trol, this is too restrictive. The sec ond approach is to create objects dyn amically in a pool of memory called the heap. In this approach, you don't know un til run-time how many objects you n eed, what their lifetime is, or what their exact type is. Those are determined at the spur of the moment while the program is runnin g. If you n eed a new object, you simply make it on the heap at the point that you n eed it. Because the storage is man aged dyn amically, at run-time, the amount of time required to allocate storage on the heap is sig ni fica ntly Ion ger tha n the time to create storage on the stack. (Creat ing storage on the stack is ofte n a si ngle assembly in structio n to move the stack poin ter dow n, and ano ther to move it back up.) The dyn amic approach makes the gen erally logical assumpti on that objects tend to be complicated, so the extra overhead of finding storage and releas ing that storage will not have an importa nt impact on the creati on of an object .In additi on, the greater flexibility is esse ntial to solve the gen eral program ming problem. Java uses the sec ond approach, exclusive". Every time you want to create an object, you use the new keyword to build a dyn amic in sta nee of that object. There's ano ther issue, however, and that's the lifetime of an object. With Ian guages that allow objects to be created on the stack, the compiler determines how long the object lasts and can automatically destroy it. However, if you create it on the heap the compiler has no kno wledge of its lifetime. In a Ianguage like C++, you must determine programmatically when to destroy the
英文翻译 英语原文： . Introducing Classes The only remaining feature we need to understand before solving our bookstore problem is how to write a data structure to represent our transaction data. In C++ we define our own data structure by defining a class. The class mechanism is one of the most important features in C++. In fact, a primary focus of the design of C++ is to make it possible to define class types that behave as naturally as the built-in types themselves. The library types that we've seen already, such as istream and ostream, are all defined as classesthat is,they are not strictly speaking part of the language. Complete understanding of the class mechanism requires mastering a lot of information. Fortunately, it is possible to use a class that someone else has written without knowing how to define a class ourselves. In this section, we'll describe a simple class that we canuse in solving our bookstore problem. We'll implement this class in the subsequent chapters as we learn more about types,expressions, statements, and functionsall of which are used in defining classes. To use a class we need to know three things: What is its name? Where is it defined? What operations does it support? For our bookstore problem, we'll assume that the class is named Sales_item and that it is defined in a header named Sales_item.h. The Sales_item Class The purpose of the Sales_item class is to store an ISBN and keep track of the number of copies sold, the revenue, and average sales price for that book. How these data are stored or computed is not our concern. To use a class, we need not know anything about how it is implemented. Instead, what we need to know is what operations the class provides. As we've seen, when we use library facilities such as IO, we must include the associated headers. Similarly, for our own classes, we must make the definitions associated with the class available to the compiler. We do so in much the same way. Typically, we put the class definition into a file. Any program that wants to use our class must include that file. Conventionally, class types are stored in a file with a name that, like the name of a program source file, has two parts: a file name and a file suffix. Usually the file name is the same as the class defined in the header. The suffix usually is .h, but some programmers use .H, .hpp, or .hxx. Compilers usually aren't picky about header file names, but IDEs sometimes are. We'll assume that our class is defined in a file named Sales_item.h. Operations on Sales_item Objects
本科生毕业设计（论文）外文科技文献译文 译文题目(外文题目)学院(系)Socket网络编程的设计与实现A Design and Implementation of Active Network Socket Programming 机械与能源工程学院 专学业 号 机械设计制造及其自动化 071895 学生姓名李杰林 日期2012年5月27日指导教师签名日期
摘要：编程节点和活跃网络的概念将可编程性引入到通信网络中，并且代码和数据可以在发送过程中进行修改。最近，多个研究小组已经设计和实现了自己的设计平台。每个设计都有其自己的优点和缺点，但是在不同平台之间都存在着互操作性问题。因此，我们引入一个类似网络socket编程的概念。我们建立一组针对应用程序进行编程的简单接口，这组被称为活跃网络Socket编程（ANSP）的接口，将在所有执行环境下工作。因此，ANSP 提供一个类似于“一次性编写，无限制运行”的开放编程模型，它可以工作在所有的可执行环境下。它解决了活跃网络中的异构性，当应用程序需要访问异构网络内的所有地区，在临界点部署特殊服务或监视整个网络的性能时显得相当重要。我们的方案是在现有的环境中，所有应用程序可以很容易地安装上一个薄薄的透明层而不是引入一个新的平台。 关键词：活跃网络；应用程序编程接口；活跃网络socket编程
1 导言 1990年，为了在互联网上引入新的网络协议，克拉克和藤农豪斯[1]提出了一种新的设 计框架。自公布这一标志性文件，活跃网络设计框架[2，3，10]已经慢慢在20世纪90 年代末成形。活跃网络允许程序代码和数据可以同时在互联网上提供积极的网络范式，此外，他们可以在传送到目的地的过程中得到执行和修改。ABone作为一个全球性的骨干网络，开 始进行活跃网络实验。除执行平台的不成熟，商业上活跃网络在互联网上的部署也成为主要障碍。例如，一个供应商可能不乐意让网络路由器运行一些可能影响其预期路由性能的未知程序，。因此，作为替代提出了允许活跃网络在互联网上运作的概念，如欧洲研究课题组提出的应用层活跃网络（ALAN）项目[4]。 在ALAN项目中，活跃服务器系统位于网络的不同地址，并且这些应用程序都可以运行在活跃系统的网络应用层上。另一个潜在的方法是网络服务提供商提供更优质的活跃网络服务类。这个服务类应该提供最优质的服务质量（QOS），并允许路由器对计算机的访问。通过这种方法，网络服务提供商可以创建一个新的收入来源。 对活跃网络的研究已取得稳步进展。由于活跃网络在互联网上推出了可编程性，相应 地应建立供应用程序工作的可执行平台。这些操作系统平台执行环境（EES），其中一些已 被创建，例如，活跃信号协议（ASP）[12]和活跃网络传输系统（ANTS）[11]。因此，不 同的应用程序可以实现对活跃网络概念的测试。 在这些EES 环境下，已经开展了一系列验证活跃网络概念的实验，例如，移动网络[5]，网页代理[6]，多播路由器[7]。活跃网络引进了很多在网络上兼有灵活性和可扩展性的方案。几个研究小组已经提出了各种可通过路由器进行网络计算的可执行环境。他们的成果和现有基础设施的潜在好处正在被评估[8，9]。不幸的是，他们很少关心互操作性问题，活跃网络由多个执行环境组成，例如，在ABone 中存在三个EES，专为一个EES编写的应用程序不能在其他平台上运行。这就出现了一种资源划分为不同运行环境的问题。此外，总是有一些关键的网络应用需要跨环境运行，如信息收集和关键点部署监测网络的服务。 在本文中，被称为活跃网络Socket编程（ANSP）的框架模型，可以在所有EES下运行。它提供了以下主要目标： ??通过单一编程接口编写应用程序。 由于ANSP提供的编程接口，使得EES的设计与ANSP 独立。这使得未来执行环境的发展和提高更加透明。
长江大学工程技术学院 毕业设计（论文）外文翻译 外 文 题 目 Matlab Based Interactive Simulation Program for 2D Multisegment Mechanical Systems 译 文 题 目 二维多段机械系统基于Matlab 的 交互式仿真程序 系 部 化学工程系 专 业 班 级 化工60801 学 生 姓 名 李泽辉 指 导 教 师 张 铭 辅 导 教 师 张 铭 完 成 日 期 2012.4.15 顶层配置在管路等，要求设备，所有设要求，对调整使案，编是指机确保机组中资料试
外文翻译 二维多段机械系统基于Matlab 的交互式仿真程序 Henryk Josiński, Adam ?witoński, Karol J?drasiak 著；李泽辉 译 摘要：本文介绍了多段机械系统设计原则，代表的是一个模型的一部分的设计系统，然后扩展 形成的几个部分和模型算法的分类与整合的过程，以及简化步骤的过程叫多段系统。本文还介绍了设计过程的二维多段机械系统的数字模型，和使用Matlab 的软件包来实现仿真。本文还讨论测试运行了一个实验，以及几种算法的计算，实现了每个单一步骤的整合。 1 简介 科学家创造了物理模型和数学模型来表示人类在运动中的各种形式。数学模型 使创建数字模型和进行计算机仿真成为可能。模型试验，可以使人们不必真正的实 验就可以虚拟的进行力和力矩的分解。 本文研究的目的是建立一个简单的多段运动模型，以增加模型的连续性和如何 避免不连续为原则。这是创建一个人类运动模型系统的冰山一角。其使用matlab 程 序包创建的数字模型，可以仿真人类运动。 文献中关于这一主题的内容很广泛。运动的模式和力矩的分解在这些文献中都 有涉猎。动态的平面人体运动模型，提出了解决了迭代矩阵的方法。还值得一提的 是这类项目的参考书目，布鲁贝克等人提出了一个模型——人腿模型，这个以人的 物理运动为基础的平面模型仿真了人腿——一个单一的扭簧和冲击碰撞模型。人腿 模型虽然简单，但是它展示人类的步态在水平地面上的运动特征。布鲁贝克等人还 介绍，在人腿模型的双足行走的基础上，从生物力学的角度而言，符合人体步行的 特征。这个模型具有一个躯干，双腿膝盖和脚踝。它能够合理的表现出人多样的步 态风格。一个仿真人类运动的数学模型反应出了人的部分运动状态。 图1. 力的分解 2 力的分解
Real-time interactive optical micromanipulation of a mixture of high- and low-index particles Peter John Rodrigo, Vincent Ricardo Daria and Jesper Glückstad Optics and Plasma Research Department, Ris? National Laboratory, DK-4000 Roskilde, Denmark jesper.gluckstad@risoe.dk http://www.risoe.dk/ofd/competence/ppo.htm Abstract: We demonstrate real-time interactive optical micromanipulation of a colloidal mixture consisting of particles with both lower (n L < n0) and higher (n H > n0) refractive indices than that of the suspending medium (n0). Spherical high- and low-index particles are trapped in the transverse plane by an array of confining optical potentials created by trapping beams with top-hat and annular cross-sectional intensity profiles, respectively. The applied method offers extensive reconfigurability in the spatial distribution and individual geometry of the optical traps. We experimentally demonstrate this unique feature by simultaneously trapping and independently manipulating various sizes of spherical soda lime micro- shells (n L≈ 1.2) and polystyrene micro-beads (n H = 1.57) suspended in water (n0 = 1.33). ?2004 Optical Society of America OCIS codes: (140.7010) Trapping, (170.4520) Optical confinement and manipulation and (230.6120) Spatial Light Modulators. References and links 1. A. Ashkin, “Optical trapping and manipulation of neutral particles using lasers,” Proc. Natl. Acad. Sci. USA 94, 4853-4860 (1997). 2. K. Svoboda and S. M. Block, “Biological applications of optical forces,” Annu. Rev. Biophys. Biomol. Struct. 23, 247-285 (1994). 3. D. G. Grier, “A revolution in optical manipulation,” Nature 424, 810-816 (2003). 4. M. P. MacDonald, G. C. Spalding and K. Dholakia, “Microfluidic sorting in an optical lattice,” Nature 426, 421-424 (2003). 5. J. Glückstad, “Microfluidics: Sorting particles with light,” Nature Materials 3, 9-10 (2004). 6. A. Ashkin, “Acceleration and trapping of particles by radiation-pressure,”Phys. Rev. Lett. 24, 156-159 (1970). 7. A. Ashkin, J. M. Dziedzic, J. E. Bjorkholm and S. Chu, “Observation of a single-beam gradient force optical trap for dielectric particles,” Opt. Lett. 11, 288-290 (1986). 8. K. Sasaki, M. Koshioka, H. Misawa, N. Kitamura, and H. Masuhara, “Optical trapping of a metal particle and a water droplet by a scanning laser beam,” Appl. Phys. Lett. 60, 807-809 (1992). 9. K. T. Gahagan and G. A. Swartzlander, “Trapping of low-index microparticles in an optical vortex,” J. Opt. Soc. Am. B 15, 524-533 (1998). 10. K. T. Gahagan and G. A. Swartzlander, “Simultaneous trapping of low-index and high-index microparticles observed with an optical-vortex trap,” J. Opt. Soc. Am. B 16, 533 (1999). 11. M. P. MacDonald, L. Paterson, W. Sibbett, K. Dholakia, P. Bryant, “Trapping and manipulation of low-index particles in a two-dimensional interferometric optical trap,” Opt. Lett. 26, 863-865 (2001). 12. R. L. Eriksen, V. R. Daria and J. Glückstad, “Fully dynamic multiple-beam optical tweezers,” Opt. Express 10, 597-602 (2002), https://www.doczj.com/doc/b35676204.html,/abstract.cfm?URI=OPEX-10-14-597. 13. P. J. Rodrigo, R. L. Eriksen, V. R. Daria and J. Glückstad, “Interactive light-driven and parallel manipulation of inhomogeneous particles,” Opt. Express 10, 1550-1556 (2002), https://www.doczj.com/doc/b35676204.html,/abstract.cfm?URI=OPEX-10-26-1550. 14. V. Daria, P. J. Rodrigo and J. Glückstad, “Dynamic array of dark optical traps,” Appl. Phys. Lett. 84, 323-325 (2004). 15. J. Glückstad and P. C. Mogensen, “Optimal phase contrast in common-path interferometry,” Appl. Opt. 40, 268-282 (2001). 16. S. Maruo, K. Ikuta and H. Korogi, “Submicron manipulation tools driven by light in a liquid,” Appl. Phys. Lett. 82, 133-135 (2003). #3781 - $15.00 US Received 4 February 2004; revised 29 March 2004; accepted 29 March 2004 (C) 2004 OSA 5 April 2004 / Vol. 12, No. 7 / OPTICS EXPRESS 1417