网站建设技术外文翻译(精选)

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第一篇:网站建设技术外文翻译(精选)

原文:

On site construction technology.Introduction

The development of network technology for today's global information exchange and sharing funding source in the establishment of contacts and provide more channels and possible.Homes will be known world affairs, according few keyboard or a few mouse clicks can be distant friends thousands of miles away exchanges, and online communications, Internet browsing, on-line interactive, e-commerce has become a modern part of people's lives.Internet era, has created the new people's work and lifestyle, the Internet, openness and sharing of information model, breaking the traditional mode of information dissemination many barriers for people with new opportunities.With computers and the advent of the information age, the pace of the advance of human society in gradually accelerated.In recent years the development of web design, fast people occupied.With the development of web design, a colorful online website together one scenic beauty.To design aesthetic and practical web site should be thoroughly master the building techniques.In building site, we analyzed the websites of objectives, contents, functions, structure, the application of more web design technology.2.the definition of website

How definition of websites 2.1

Web site identified the tasks and objectives, the building site is the most important issue.Why people will come to your website? You have a unique service? The first people to your website is to what? They will come back? All these issues must be taken into account when the site definition of the problem.Definition site to, first of all, the entire site must have a clear understanding of what the design should understand in the end, the main purpose of the mission, how to carry out the task of organization and planning.Second, to maintain the high-quality Web site.Many websites in the face of strong competition from high-quality product is the greatest long-term competitive advantage.An excellent Web site should have the following:

(1)users visit Web site is faster.(2)attention to the feedback and updates.To update the content of the website and timely feedback the user's requirements;

(3)Home design to be reasonable.Home to the first impression left by visitors is important, the design must be attractive in order to have a good visual effect.2.2 The contents of the website and function

The content of the web site is to be a new, fast, all three sides.The content of the website, including the type of static, dynamic, functional and things to deal with.Website content is determined in accordance with the nature of the site, in the design of the site, commercial websites, popular science site, company websites, teaching and exchange websites, the content and style are different.We have established websites with the nature of these types of sites are not the same.2.3 The structure website(1)site structure;

(2)definition of navigation;(3)Visual Design;

(4)framework and design pages.3.Site Design and Implementation

With increasing demands on design, high style, high-grade design work before gaining popularity.This also to the designers have put forward higher requirements, from this point of view, the plate design is to meet the requirements of the people should be and Health.The rapid development of science and technology, the Internet into millions of households, also produced a new design space, and a new web design an important part of the field of design.Excellent web design, we must have good creative, so that the audience can be difficult to shift attention long time, produce power.Layout is very important, through text, graphics space portfolio, can best express harmony with the United States.If you want to further understand website design, made separately from other web site's homepage, you need to have more like CSS, javascript, CGI, and other web design technology.In building on the site of the CSS, javascript and other web design technology.CSS 3.1 Application Design website

(1)What is CSS? CSS is a style sheet(stylesheet)technology.Some of them called CSS(Cascading Stylesheet).(2)the combination of CSS and HTML form.Mode 1: The CSS content, as defined in the writing between the labels.Mode 2: CSS will be preserved as a separate text file, and then from labels to call.(3)CSS the web site of examples.The web site pages, and increase the following definition so that the pages show with special effects.3.2 Application Design website javascript

Javascript and the emergence of making information between users is not only a display and browse the relationship, but to achieve a real-time, dynamic, cross-expression.Thus based on the CGI static HTML pages will be to provide dynamic real-time information, and customer response to the operation of the Web pages replaced.javascript scripting is satisfy this demand arising from the language.It's loved by extensive user.Many scripting language it is in a relatively good..A.S.Boranbayev, Optimal Methods for Java Web Services, News of the National Academy of Science of the Republic of Kazakhstan, 5(2007), 38-43.

第二篇:jsp技术网站设计外文翻译

外文翻译

工 学 部

业 班

级 学

号 姓

名 指导教师 负责教师

工学一部 网络工程 B741111 B74111104 王雨娉 潘琢金

沈阳航空航天大学北方科技学院

2011年6月沈阳航空航天大学北方科技学院毕业设计(论文)外文翻译——原文

Combining JSP and Servlets The technology of JSP and Servlet is the most important technology which use Java technology to exploit request of server, and it is also the standard which exploit business application.Java developers prefer to use it for a variety of reasons, one of which is already familiar with the Java language for the development of this technology are easy to learn Java to the other is “a preparation, run everywhere” to bring the concept of Web applications, To achieve a “one-prepared everywhere realized.” And more importantly, if followed some of the principles of good design, it can be said of separating and content to create high-quality, reusable, easy to maintain and modify the application.For example, if the document in HTML embedded Java code too much(script), will lead the developed application is extremely complex, difficult to read, it is not easy reuse, but also for future maintenance and modification will also cause difficulties.In fact, CSDN the JSP / Servlet forum, can often see some questions, the code is very long, can logic is not very clear, a large number of HTML and Java code mixed together.This is the random development of the defects.Early dynamic pages mainly CGI(Common Gateway Interface, public Gateway Interface)technology, you can use different languages of the CGI programs, such as VB, C / C + + or Delphi, and so on.Though the technology of CGI is developed and powerful, because of difficulties in programming, and low efficiency, modify complex shortcomings, 沈阳航空航天大学北方科技学院毕业设计(论文)外文翻译——原文

it is gradually being replaced by the trend.Of all the new technology, JSP / Servlet with more efficient and easy to program, more powerful, more secure and has a good portability, they have been many people believe that the future is the most dynamic site of the future development of technology.Similar to CGI, Servlet support request / response model.When a customer submit a request to the server, the server presented the request Servlet, Servlet responsible for handling requests and generate a response, and then gave the server, and then from the server sent to the customer.And the CGI is different, Servlet not generate a new process, but with HTTP Server at the same process.It threads through the use of technology, reduce the server costs.Servlet handling of the request process is this: When received from the client's request, calling service methods, the method of Servlet arrival of the first judgement is what type of request(GET / POST / HEAD…), then calls the appropriate treatment(DoGet / doPost / doHead…)and generate a response.Although such a complex, in fact, simply said to Servlet is a Java class.And the general category of the difference is that this type operating in a Servlet container, which can provide session management and targeted life-cycle management.So that when you use the Servlet, you can get all the benefits of the Java platform, including the safety of the management, use JDBC access the database and cross-platform capability.Moreover, Servlet using thread, and can develop more efficient Web applications.JSP technology is a key J2EE technology, it at a higher level of abstraction of a Servlet.沈阳航空航天大学北方科技学院毕业设计(论文)外文翻译——原文

It allows conventional static and dynamic HTML content generated by combining an HTML page looks like, but as a Servlet to run.There are many commercial application server support JSP technology, such as BEA WebLogic, IBM WebSphere, JRun, and so on.JSP and Servlet use more than simple.If you have a JSP support for Web servers, and a JSP document, you can put it Fangdao any static HTML files can be placed, do not have to compile, do not have to pack, do not have to ClassPath settings, you can visit as ordinary Web It did visit, the server will automatically help you to do other work.JSP document looks like an ordinary static HTML document, but inside contains a number of Java code.It uses.Jsp the suffix, used to tell the server this document in need of special treatment.When we visit a JSP page, the document will first be translated into a JSP engine Java source files, is actually a Servlet, and compiler, and then, like other Servlet, from Servlet engine to handle.Servlet engine of this type loading, handling requests from customers, and the results returned to the customer, as shown below:

Figure 1: Calling the process of JSP pages 沈阳航空航天大学北方科技学院毕业设计(论文)外文翻译——原文

After another visit this page to the customer, as long as the paper there have been no changes, JSP engine has been loaded directly call the Servlet.If you have already been modified, it will be once again the implementation of the above process, translate, compile and load.In fact, this is the so-called “first person to punishment.” Because when the first visit to the implementation of a series of the above process, so will spend some time after such a visit would not.Java servlets offer a powerful API that provides access to all the information about the request, the session, and the application.combining JSP with servlets lets you clearly separate the application logic from the presentation of the application;in other words, it lets you use the most appropriate component type for the roles of Model, View and Controller.Servlets, Filters, and Listeners

A servlet is a Java class that extends a server with functionality for processing a request and producing a response.It's implemented using the classes and interfaces defined by the Servlet API.The API consists of two packages: the javax.servlet package contains classes and interfaces that are protocol-independent, while the javax.servlet.http package provides HTTP-specific extensions and utility classes.What makes a servlet a servlet is that the class implements an interface named javax.servlet.Servlet, either directly or by extending one of the support classes.This interface defines the methods used by the web container to manage and interact with the 沈阳航空航天大学北方科技学院毕业设计(论文)外文翻译——原文

servlet.A servlet for processing HTTP requests typically extends the javax.servlet.http.HttpServlet class.This class implements the Servlet interface and provides additional methods suitable for HTTP processing.Servlet Lifecycle The web container manages all aspects of the servlet's lifecycle.It creates an instance of the servlet class when needed, passes requests to the instance for processing, and eventually removes the instance.For an HttpServlet, the container calls the following methods at the appropriate times in the servlet lifecycle.Besides the doGet()and doPost()methods, there are methods corresponding to the other HTTP methods: doDelete(), doHead(), doOptions(), doPut(), and doTrace().Typically you don't implement these methods;the HttpServlet class already takes care of HEAD, OPTIONS, and TRACE requests in a way that's suitable for most servlets, and the DELETE and PUT HTTP methods are rarely used in a web application.It's important to realize that the container creates only one instance of each servlet.This means that the servlet must be thread safe--able to handle multiple requests at the same time, each executing as a separate thread through the servlet code.Without getting lost in details, you satisfy this requirement with regards to instance variables if you modify the referenced objects only in the init()and destroy()methods, and just read them in the request processing methods.沈阳航空航天大学北方科技学院毕业设计(论文)外文翻译——原文

Compiling and Installing a Servlet To compile a servlet, you must first ensure that you have the JAR file containing all Servlet API classes in the CLASSPATH environment variable.The JAR file is distributed with all web containers.Tomcat includes it in a file called servlet.jar, located in the common/lib directory.On a Windows platform, you include the JAR file in the CLASSPATH..Reading a Request One of the arguments passed to the doGet()and doPost()methods is an object that implements the HttpServletRequest interface.This interface defines methods that provide access to a wealth of information about the request.Generating a Response Besides the request object, the container passes an object that implements the HttpServletResponse interface as an argument to the doGet()and doPost()methods.This interface defines methods for getting a writer or stream for the response body.It also defines methods for setting the response status code and headers.Using Filters and Listeners The servlet specification defines two component types beside servlets: filters and listeners.These two types were introduced in the Servlet 2.3 specification, so if you're using a container that doesn't yet support this version of the specification, I'm afraid you're 沈阳航空航天大学北方科技学院毕业设计(论文)外文翻译——原文

out of luck.Filters A filter is a component that can intercept a request targeted for a servlet, JSP page, or static page, as well as the response before it's sent to the client.This makes it easy to centralize tasks that apply to all requests, such as access control, logging, and charging for the content or the services offered by the application.A filter has full access to the body and headers of the request and response, so it can also perform various transformations.One example is compressing the response body if the Accept-Language request header indicates that the client can handle a compressed response.A filter can be applied to either a specific servlet or to all requests matching a URL pattern, such as URLs starting with the same path elements or having the same extension.Listeners

Listeners allow your application to react to certain events.Prior to Servlet 2.3, you could handle only session attribute binding events(triggered when an object was added or removed from a session).You could do this by letting the object saved as a sessionattribute(using

the

HttpSession.setAttribute()

method)implement

the HttpSessionBindingListener interface.With the new interfaces introduced in the 2.3 version of the specification, you can create listeners for servlet context and session lifecycle events as well as session activation and passivation events(used by a container that temporarily saves session state to disk or migrates a session to another server).A new 沈阳航空航天大学北方科技学院毕业设计(论文)外文翻译——原文

session attribute event listener also makes it possible to deal with attribute binding events for all sessions in one place, instead of placing individual listener objects in each session.The new types of listeners follow the standard Java event model.In other words, a listener is a class that implements one or more of the listener interfaces.The interfaces define methods that correspond to events.The listener class is registered with the container when the application starts, and the container then calls the event methods at the appropriate times.Initializing Shared Resources Using a Listener Beans like this typically need to be initialized before they can be used.For instance, they may need a reference to a database or some other external data source and may create an initial information cache in memory to provide fast access even to the first request for data.You can include code for initialization of the shared resources in the servlet and JSP pages that need them, but a more modular approach is to place all this code in one place and let the other parts of the application work on the assumption that the resources are already initialized and available.An application lifecycle listener is a perfect tool for this type of resource initialization.This type of listener implements the javax.servlet.ServletContextListener interface, with methods called by the container when the application starts and when it shuts down.Picking the Right Component Type for Each Task The Project Billboard application introduced is a fairly complex application.Half the 沈阳航空航天大学北方科技学院毕业设计(论文)外文翻译——原文

pages are pure controller and business logic processing, it accesses a database to authenticate users, and most pages require access control.In real life, it would likely contain even more pages, for instance, pages for access to a shared document archive, time schedules, and a set of pages for administration.As the application evolves, it may become hard to maintain as a pure JSP application.It's easy to forget to include the access control code in new pages.This is clearly an application that can benefit from using a combination of JSP pages and the component types defined by the servlet specification for the MVC roles.Let's look at the main requirements and see how we can map them to appropriate component types:  Database access should be abstracted, to avoid knowledge of a specific data schema or database engine in more than one part of the application: beans in the role of Model can be used to accomplish this. The database access beans must be made available to all other parts of the application when it starts: an application lifecycle event listener is the perfect component type for this task. Only authenticated users must be allowed to use the application: a filter can perform access control to satisfy this requirement. Request processing is best done with Java code: a servlet, acting as the Controller, fits the bill. It must be easy to change the presentation: this is where JSP shines, acting as the 沈阳航空航天大学北方科技学院毕业设计(论文)外文翻译——原文

View.Adding servlets, listeners, and filters to the mix minimizes the need for complex logic in the JSP pages.Placing all this code in Java classes instead makes it possible to use a regular Java compiler and debugger to fix potential problems.Centralized Request Processing Using a Servlet With a servlet as the common entry point for all application requests, you gain control over the page flow of the application.The servlet can decide which type of response to generate depending on the outcome of the requested action, such as returning a common error page for all requests that fail, or different responses depending on the type of client making the request.With the help from some utility classes, it can also provide services such as input validation, I18N preparations, and in general, encourage a more streamlined approach to request handling.When you use a servlet as a Controller, you must deal with the following basic requirements:

 All requests for processing must be passed to the single Controller servlet. The servlet must be able to distinguish requests for different types of processing.Here are other features you will want support for, even though they may not be requirements for all applications:

 A strategy for extending the application to support new types of processing requests in a flexible manner.沈阳航空航天大学北方科技学院毕业设计(论文)外文翻译——原文

 A mechanism for changing the page flow of the application without modifying code.Mapping Application Requests to the Servlet The first requirement for using a Controller servlet is that all requests must pass through it.This can be satisfied in many ways.If you have played around a bit with servlets previously, you're probably used to invoking a servlet with a URI that starts with /myApp/servlet.This is a convention introduced by Suns Java Web Server(JWS), the first product to support servlets before the API was standardized.Most servlet containers support this convention today, even though it's not formally defined in the servlet specification.沈阳航空航天大学北方科技学院毕业设计(外文翻译)

将Servlet和JSP组合使用

Servlet和JSP技术是用Java开发服务器端应用的主要技术,是开发商务应用表示端的标准。Java开发者喜欢使用它有多种原因,其一是对于已经熟悉Java语言的开发者来说这个技术容易学习;其二是Java把“一次编写,到处运行”的理念带入到Web应用中,实现了“一次编写,到处实现”。而且更为重要的是,如果遵循一些良好的设计原则的话,就可以把表示和内容相分离,创造出高质量的、可以复用的、易于维护和修改的应用程序。比方说,在HTML文档中如果嵌入过多的Java代码(scriptlet),就会导致开发出来的应用非常复杂、难以阅读、不容易复用,而且对以后的维护和修改也会造成困难。事实上,在CSDN的JSP/Servlet论坛中,经常可以看到一些提问,代码很长,可以逻辑却不是很清晰,大量的HTML和Java代码混杂在一起,让人看得一头雾水。这就是随意开发的弊端。

早期的动态网页主要采用CGI(Common Gateway Interface,公共网关接口)技术,你可以使用不同的语言编写CGI程序,如VB、C/C++或Delphi等。虽然CGI技术发展成熟且功能强大,但由于编程困难、效率低下、修改复杂等缺点,所以有逐渐被取代的趋势。在所有的新技术中,JSP/Servlet具备更高效、更容易编程、功能更强、更安全和具有良好的可移植性,因而被许多人认为是未来最有发展前途的动态网站技术。

与CGI相似,Servlet支持请求/响应模型。当一个客户向服务器递交一个请求时,服务器把请求送给Servlet,Servlet负责处理请求并生成响应,然后送给服务器,再由服务器发送给客户。与CGI不同的是,Servlet没有生成新的进程,而是与HTTP Server处于同一进程中。它通过使用线程技术,减小了服务器的开销。Servlet处理请求的过程是这样的:当收到来自客户端的请求后,调用service方法,该方法中Servlet先判断到来的请求是什么类型的(GET/POST/HEAD„),然后调用相应的处理方法(doGet/doPost/doHead„)并生成响应。

沈阳航空航天大学北方科技学院毕业设计(外文翻译)别看这么复杂,其实简单说来Servlet就是一个Java类。与一般类的不同之处是,这个类运行在一个Servlet容器内,可以提供session管理和对象生命周期管理。因而当你使用Servlet的时候,你可以得到Java平台的所有好处,包括安全性管理、使用JDBC访问数据库以及跨平台的能力。而且,Servlet使用线程,因而可以开发出效率更高的Web应用。

JSP技术是J2EE的一个关键技术,它在更高一级的层次上抽象Servlet。它可以让常规静态HTML与动态产生的内容相结合,看起来像一个HTML网页,却作为Servlet来运行。现在有许多商业应用服务器支持JSP技术,比如BEA WebLogic、IBM WebSphere、JRun等等。使用JSP比用Servlet更简单。如果你有一个支持JSP的Web服务器,并且有一个JSP文件,你可以把它放倒任何静态HTML文件可以放置的位置,不用编译,不用打包,也不用进行ClassPath的设置,就可以像访问普通网页那样访问它,服务器会自动帮你做好其他的工作。

JSP 文件看起来就像一个普通静态HTML文件,只不过里面包含了一些Java代码。它使用.jsp的后缀,用来告诉服务器这个文件需要特殊的处理。当我们访问一个JSP页面的时候,这个文件首先会被JSP引擎翻译为一个Java源文件,其实就是一个Servlet,并进行编译,然后像其他Servlet一样,由Servlet引擎来处理。Servlet引擎装载这个类,处理来自客户的请求,并把结果返回给客户,如下图所示:

图1: 调用JSP页面的流程

沈阳航空航天大学北方科技学院毕业设计(外文翻译)以后再有客户访问这个页面的时候,只要该文件没有发生过更改,JSP引擎就直接调用已经装载的Servlet。如果已经做过修改的话,那就会再次执行以上过程,翻译、编译并装载。其实这就是所谓的“第一人惩罚”。因为首次访问的时候要执行一系列以上的过程,所以会耗费一些时间;以后的访问就不会这样了。

Java servlet提供了一种强有力的API,用这个API可以访问关于请求、会话和应用程序的所有信息。将servlet和JSP页面组合起来使用,可以把应用程序的逻辑部分和外观呈现部分清楚地分开;换句话,利用这个方式可以对模型、视图和控制器这三种角色分别使用最合适的组件类型。Servlet、过滤器和监听器

Servlet是一种Java类,它使得服务器的功能可扩展至处理请求和生成应答。它是用Servlet API定义的类和接口实现的。API由两个程序包组成:jvavax.servlet程序包包含独立于协议的类和接口,而javax.servlet.http程序包则提供HTTP特定的扩展的实用程序类。

Servlet的实质是实现了接口javax.servlet.Servlet的类,实现是直接完成或通过扩展某个支持类来完成的。该接口定义了Web容器用来管理servlet和与之交互的方法。用于处理HTTP请求的servlet一般情况下都会扩展javax.servlet.http.HttpServlet类。该类实现了Servlet接口,并提供了使用HTTP处理的附加方法。Servlet的生命周期

Web容器管理servlet生命周期的所有方面。它根据需要创建servlet类的实例、将请求传递给实例进行处理,最终删除实例。对于HttpServlet来说,容器会在servlet生命周期的适当时间调用方法。

除了doGet()和doPost()方法之外,还有一些对应于其他HTTP方法的方法:doDelete()、doHead()、doOptiongs()、doPut()和doTrace()。一般情况下不用实现这些方法,因为HttpServlet类已经用适用于大多数servlet的方法考虑到了HEAD、OPTIONS和TRACE请求,而且DELETE和PUT这两种HTTP方法很少用在Web应用程序中。

沈阳航空航天大学北方科技学院毕业设计(外文翻译)容器只为每个Servlet创建一个实例非常重要。这意味着servlet必须是线程安全的—即,能够同时处理多个请求,每个处理都通过servlet代码作为单独的线程来执行。如果只在init()和destroy()方法中修改参考的对象,而且只在请求处理方法中读取他们,那么不用丧失任何细节就可以满足关于实例变量的这个要求。编译和安装servlet 要编译servlet,必须首先确保JAR文件包含着CLASSPATH环境变量中所有Servlet API类。该JAR文件将随所有的Web容器一起发布。Tomcat中包含了一个名为servlet.jar的JAR文件,位于common/lib目录中。在Windows平台中,应在CLASSPATH中包含JAR文件。读取请求

传递到doGet()和doPost()方法的参数之一是实现了HttpServletRequest接口的对象。该接口定义的方法可提供对关于请求的许多信息的访问。生成应答

除应答对象之外,容器还将实现HttpServletRequest接口的对象作为icanshu传递给doGet()和doPost()方法。该接口定义了为应答行为体获取数序程序或流的方法。它还定义了设置应答状态代码和首部的方法。使用过滤器和监听器

Servlet规范servlet内定义了两种组件类型:过滤器和监听器。这两种类型是在Servlet 2.3规范中引入的,因此,如果你使用的是不支持该版本规范的容器,恐怕就不能继续学习了。过滤器

过滤器是一种组件,可以解释对servlet、JSP页面或静态页面的请求以及发送给客户端之前的应答。这样可以很容易地将应用于所有请求的任务集中在一起,例如访问控制、登录和内容的开销或应用提供的服务等。过滤器对请求与应答的行为体和首部具有完全访问权限,因此还可以执行各种转换。例如,如果Accept-Language请求

沈阳航空航天大学北方科技学院毕业设计(外文翻译)首部指出客户端可以处理压缩的应答,那么过滤器就可以压缩应答的行为体。

过滤器可以应用在特定servlet上,或匹配某种URL模式的所有请求上,例如以相同的路径元素开头或具有相同扩展名的URL。监听器

监听器允许应用程序对特定事件做出回应。Servlet 2.3之前,只能处理会话属性绑定事件(在添加对象或从会话中删除对象时)。实现监听器的方式是用保存为会话属性(使用HttpSession.setAttribute()方法)的对象实现HttpSessionBinding-Listener接口。随着Servlet规范的2.3版本中新接口的引入,可以为servlet环境和会话生命周期事件以及激活和钝化事件(容器用来暂时将会话状态保存在磁盘上或将会话移植到另一个服务器上)创建监听器。使用新的会话属性事件监听器还可以在一个位置上处理所有会话的属性绑定事件,而不是在每个会话中防止单独的监听器对象。

新类型的监听器遵循的是标准Java事件模型。换句话说,监听器是实现了一个或多个监听器接口的类。接口定义的是事件相应的方法。当应用程序启动是,容易会注册监听器类,然后该容器会在合适的事件调用那些事件方法。使用监听器初始化共享资源

Bean一般都有需要在使用之前进行初始化。例如,它们可能需要对数据库或某些其他外部数据源的引用,还可能在内存中创建一个初始消息缓存,以便即使是第一个请求数据也可以提供更快的访问。可以在需要共享资源的servlet和JSP页面中包含初始化共享资源的代码,但是更标准的方法是在一个位置放置所有这些代码,并在假设资源已经初始化和可用的情况下,使应用程序的其他部分可以正常工作。应用程序生命周期监听器是此类资源初始化的绝好工具。此类监听器实现了javax.servlet.ServletContextListener接口,当应用程序启动和关闭时会由容器调用该接口的方法。

为每个任务选择正确的组件类型

在之前介绍的项目公告牌应用程序是相当复杂的应用程序。页面的一般都是纯粹的控制器和商务逻辑处理,它访问数据库以对用户进行身份验证,而且多数页面都需

沈阳航空航天大学北方科技学院毕业设计(外文翻译)要访问控制。在现实生活中,它可能会包含更多的页面,例如,用于访问共享文档档案、事件表的页面和用于管理的一组页面等。由于应用程序在不断地发展变化,因此可能变得很难作为纯JSP应用程序来维护。例如,很容易忘记在新页面中包含访问控制代码。

很明显,这种应用程序可以从使用JSP页面与组件类型的组合中受益,其中组件类型由用于MVC角色的servlet规范所定义。下面看一下主要的要求,并了解如何将他们映射到适当的组件类型上:

 数据库访问应该是抽象的,从而避免料接应用程序中多个部分的特定数据模式或数据库引擎:模型角色中的bean可以用来完成这种认知。

 数据库访问bean必须在应用程序启动时可用于所有其他的部分:应用程序生命周期时间监听器是用了该任务的完美的组件类型。

 只有通过验证的用户才允许使用应用程序:过滤器可以完成访问控制以满足该要求。

 用Java代码进行请求处理效果最佳:servlet作为控制器正符合需要。 必须很容易改编外观呈现:这正是JSP的反光点,也就是作为视图。将servlet、监听器和过滤器混合起来,就将JSP页面对复杂逻辑的需求降到了最低。将这些代码放置到Java类中后,就可以使用普通的Java编译程序和调试程序来修复潜在的问题。

使用servlet集中处理请求

将servlet作为所有应用程序请求的公共入口时,可以获得对应用程序页面流的整体控制。Servlet可以根据所请求行为的结果来决定要生成的应答类型,例如,为所有失败的请求返回公共的错误页面,或者根据发出请求的客户端返回不同的应答等。在某些使用程序类的帮助下,servlet还可以提供诸如输入验证、J18N准备之类的服务,而且通常会鼓励使用更有效率的方法来请求处理。

当使用servlet作为控制器时,必须处理下列基本要求:  所有处理请求必须传递到单独的控制器servlet中。

沈阳航空航天大学北方科技学院毕业设计(外文翻译) Servlet必须能够区分请求,以便进行不同类型的处理。

下面是其他一些你可能希望支持的功能,即使并非所有应用程序都要求:  扩展应用程序以便以更灵活的方式支持新类型的请求处理。 在不修改代码的情况下改变应用程序页面流的机制。

当然,你可以自己开发满足这些要求的servlet,但是已经有开源式servlet了,他们可以满足所有这些要求,甚至还有更多的功能。将应用程序请求映射到servlet 使用控制器servlet的第一个要求是所有请求必须都经过该servlet。该要求可以通过多种方式来满足。如果你以前曾经使用过servlet,那么你可能习惯于用以/myApp/servlet开头的URI来调用servlet。这是由Sun公司的Java Web Server(JWS)所引入的一个约定,JWS是在推出标准API之前第一个支持servlet的产品。今天,大部分servlet容器都支持这个约定,即使servlet规范中并没有正式的定义。

第三篇:网站远程管理外文翻译

湖北大学本科毕业论文(设计)外文翻译

外文翻译:

浅谈网络中的远程控制

原文来源:

Rabiner, L.R.;Gold, B.Englewood Cliffs, N.J., Prentice-Hall, Inc., 2009 p.译文正文:

摘要:在网络高速发展的今天,随着计算机应用的普及,远程控制也逐渐被人们所关注。远程控制是网络的一大优势,在网络管理、远程协作、远程办公等计算机领域都有着广泛的应用,它进一步克服了由于地域性的差异而带来的操作中的不便性,使得网络的效率得到了更大的发挥。远程控制可通过多种方法加以实现。关键词:远程控制;遥控操作;技术应用;实现方法 计算机远程控制

计算机远程控制是在网络上由一台电脑(主控端Remote/客户端)远距离去控制另一台电脑(被控端Host/J]服务器端)的技术⋯。这里的远程不是字面意思的远距离,而是指通过网络来对远端的计算机实施遥控。

远程控制只是通过网络来操纵计算机的一种手段而已,只要运用得当,操纵远程的计算机也就如同你操纵眼前正在使用的计算机一样没有任何区别。当操作者使用主控端电脑控制被控端电脑时,就如同坐在被控端电脑的屏幕前一样,可以启动被控端电脑的应用程序,可以使用被控端电脑的文件资料,甚至可以利用被控端电脑的外部打印设备和通信设备来进行打印和访问互联网。在这个过程中主控端电脑只是将键盘和鼠标的指令传送给远程电脑,同时将被控端电脑的屏幕画面通过通信线回传过来。也就是说,我们控制被控端电脑进行操作似乎是在眼前的电脑上进行的,实质是在远程的电脑中实现的,不论打开文件,还是上网浏览、下载,所有的资料和上网等都是存储在远程的被控端电脑中的。

实行远程控制,实际上就是一个服务器程序(以下简称被控程序)和一个客户程序(以下简称主控程序),被控方即为服务器程序,它监听客户的请求,并做出处理;主控方即为客户程序,它连接上服务器后,发出自己的请求,服务器便根据客户的请求做出不同的响应。远程控制系统组成如图1所示。

当今的远程控制技术支持的网络方式有:LAN、WAN、拨号方式、互联网方式。此外,有的远程控制软件还支持通过串口、并口、红外端口来对远程机进行控制。远程控制克服了由于地域性的差异而带来的操作中的不便性,使得网络的效率得到了更大的发挥。

2远程控制的技术实现

2.1远程控制的原理

“只要网络有通路就可以实现远程控制”,远程控制必须通过网络才能进行。位于本地的、已被安装了客户端程序的主控端是操纵指令的发出端,它像一个普通客户一样向非本地、安装了服务器端程序的被控端发出信号,建立并通过一个特殊的远程服务,使用各种远程控制功能发送远程控制命令,控制被控端电脑中的各种应用程序运行,使得被控端按照主控端的 要求进行各种操作,从而实现远程控制的目的。图2远程控制示意图

湖北大学本科毕业论文(设计)外文翻译

通过网络实现的远程控制示意图如图2所示。

2.2远程控制实现方法

2.2.1 利用微软Windows XP系统中远程控制功能

每台Windows XP电脑都同时包括客户端和服务器端,也就是说它既可以当成客户端来连接其他的Windows XP电脑,也可以将自己当成服务器端,让别的电脑来控制自己。服务器端的系统都是使用Windows XP,而客户端就可以是Windows XP、Windows 2000或者Windows Me,并且对客户端没有语言的限制。用户可以利用远程桌面通过网络对远程计算机进行控制,控制后可以访问所有应用程序、文件和网络资源等。

2.2.2利用一些功能强大的远程控制软件。

远程控制技术发展到今天,产生了许多优秀的远程控制软件,有提供多层次安全防护的远程遥控软件,还有加速远程遥控操作软件,以及更加利于快速文档传送的控制软件。还有如“RemotelyAnywhere”只需在服务器端一次性安装,客户端在网络中不需要再增加任何软件,就可以直接通过浏览器来对服务器进行远程控制。它不仅仅只是让客户端能够远程控制服务器的桌面,还可以给多个用户设置不同的权限,以便让他们根据授权对服务器的文件管理器、注册表等项目进行查询和管理;它允许服务器和客户端之间传递剪贴板,也可实现普通文档的传送。另外,一些集远程控制、数据通信和文件传输等功能于一体,具有很高的数据传输效率和系统安全保障的远程控制系统正在被推广。

2.2.3根据实际需求开发实现远程控制

自行开发实现远程控制,涉及主控机和受控机,故采用Client/Server结构。可以用Delphi编程环境分别在两台不同的电脑上编制控制和被控制程序,一个为Clientdpr.exe,装在受控机上;另一个为Serverdpr.exe,装在主控机上。Serverdpr.exe指定要监视的受控机的IP地址和发送指令给客户机的Clientdpr.exe,客户机的Clientdpr.exe得到指令后,接着在本机执行相应指令,将结果返回给主控机。主控方的功能是这样实现的:读取命令串一将命令串转换成数组一清除内存流一指定目标计算机(通过读取所输入的IP地址)一将指令码发送给目标计算机。当主控机将指令发给受控机后,受控机将在本机上调用Windows的应用程序接口API函数以执行所接收的指令。当受控机接收到数据时,便开始执行主控机发送的操作。具体操作是这样的:读取控制码_+识别控制码一执行相应的过程或API函数以达到相应的功能。结束语

远程控制虽然可以方便地操纵远程计算机,给人们带来很多便利,但它也会由此带来安全方面的隐患。随着远程控制市场的成熟,网络安全变得越发重要,只有彻底解决这一关键问题,才能促进远程控制真正走向应用。

湖北大学本科毕业论文(设计)外文翻译

Remote control of network

Abstract: The rapid development of the network today, with the popularization of computer applications, remote control have gradually been of concern to the people.Network remote control is a major advantage in network management, remote collaboration, remote office and other computer fields have a wide range of applications, it further to overcome regional differences in the operation brought the inconvenience, making the network efficiency Given greater play.Remote control can be achieved through a variety of ways.Keywords: remote control;remote operation;technology;Implementation 1 computer remote control

Computer remote control is on the network by a computer(host Remote / Client)remote to control another computer technology.Here is not the literal meaning of the long-distance remote, but rather through the network to the remote computer on the implementation of remote control.Remote control is to manipulate the computer through the network as a means only, if used properly, will control the remote computer as you manipulate the front of the computer being used as there is no difference.When the operator using the host computer control host computer to host computer as if sitting in front of the screen as the computer can start the host application, you can use the host computer documentation, or even Host computer using the external printing device and communications equipment to print and access the Internet.In this process, host computer is just a keyboard and mouse commands sent to the remote computer, while host computer's screen image come through the communication line return.That is, we control the host computer to operate in front of the computer seems to be carried out, in essence, a remote computer to achieve, whether to open the file, or Web browsing, downloading, all the information and the Internet are all Stored in the remote host computer.Implementation of remote control, in fact, a server program(hereinafter referred to as charged program)and a client(hereinafter referred to as master control program), the prosecution is the server program that listens to customer requests, and to deal with it;Master Is the client side, it is connected to the server, to make their request, the server will be made according to customer's request a different response.Remote control system shown in Figure 1.Today's technical support network remote control methods are: LAN, WAN, dial-up Internet way.In addition, some remote control software also supports serial, parallel, infrared port to control a remote machine.Remote control to overcome regional differences in the operation brought the inconvenience, make the network to play a greater efficiency.2 remote control technology 2.1 Principles of remote control

“As long as the network has access to connect remote control ”, remote control must be carried out through the network.At local, has been installed, the host is a client program to issue control instructions side, it is the same as an ordinary customer to non-local, the installation of the host server program signals, and through the establishment of a special Remote service, using a variety of remote control function to send a remote control command, control, host computers running various applications, making the host in accordance with the master's

湖北大学本科毕业论文(设计)外文翻译

Requirements for various operations, in order to achieve the remote control.Figure 2 Schematic diagram of the remote control

Remote control through the network diagram shown in Figure 2.2.2Implementation of Remote Control 2.2.1 Microsoft Windows XP system using the remote control function

Windows XP computers each include both client and server side, meaning that both can be used as a client to connect to other Windows XP computer, you can also themselves as the server side, so that other computer to control themselves.Server systems are using Windows XP, the client can be Windows XP, Windows 2000 or Windows Me, and the client without language restrictions.Users can use the Remote Desktop computer through the network to the remote control, after controlling for access to all applications, files and network resources.2.2.2 using some powerful remote control software.Remote control technology to today, have a lot of great remote control software, providing multi-level security protection for remote control software, as well as speed up the remote control operating software, and more conducive to the rapid document transmission control software.Also, as “RemotelyAnywhere” just a one-time installation on the server side, the client in the network do not need to add any software to connect directly through the browser on the server for remote control.It is not just the client to remotely control the server's desktop, but also can set different permissions for multiple users so that they are under the authority of the server's file manager, registry, query and manage projects;it allows the server and Clipboard passed between the client can also be transmitted to achieve common document.In addition, some set of remote control, data communications and file transfer and other functions into one, with high data transmission efficiency and system security remote control system is being promoted.2.2.3 Development and implementation of the actual needs of the remote control

Develop their own remote control, involving the host computer and controlled machines, so the use of Client / Server structure.Delphi programming environment can be used separately on two different computers to be controlled preparation of control and procedures, one for Clientdpr.exe, installed in the controlled machine;one for Serverdpr.exe, installed in the main computer on.Serverdpr.exe designated to monitor the controlled machine IP address and send instructions to the client Clientdpr.exe, client Clientdpr.exe get command, and then execute the corresponding instructions in the machine, the results are returned to the host computer.Master side function is implemented as follows: Read command string into a string array of commands to clear the memory of a stream to a specified target computer(by reading the entered IP address)to send the script to a target computer.When the command sent to the host computer controlled machine, the machine will be controlled on the unit's application program interface calls Windows API functions to perform the received command.When the controlled unit receives the data, they begin to send the host computer operation.To do this: Read identification control code _ + implementation of the corresponding control code for a procedure or function to achieve the appropriate API function.3 Conclusion

Although the remote control can easily manipulate the remote computer, to bring a lot of convenience, but it also the resulting security risks.As the market matures remote control, network security becomes more important, only solve this critical issue, to really go for remote

control applications.

第四篇:社交网站_外文翻译

社交网站

我们定义的社交网络站点作为基于Web的服务,允许个人:(1)有界系统内构建一个公共或半公共的配置文件。(2)阐明列表中的其他用户,与他们共享一个连接。

(3)查看和遍历他们的名单和那些由其他系统内的连接。性质和命名这些连接可能会有所不同,从站点到站点。

虽然我们使用的术语―社交网站‖来形容这种现象,―社交网站‖也出现在公共话语中,经常交替使用这两个术语。我们选择不采用―联网‖的原因有两个:重点和范围。―物联网‖强调关系启动,往往陌生人之间。虽然网络是可能在这些网站上,它是不是主要的做法,他们中的许多,也不是有什么区别他们从其他形式的计算机中介传播(CMC)。

是什么让独特的社交网站并不是说他们允许个人见陌生人,而是他们让使用者能够表达,使人们看到他们的社交网络。这可能会导致个人之间的连接,否则不会进行,但往往不是我们的目标,而这些会议之间―的潜在关系‖(Haythornthwaite,2005年)谁分享一些脱机连接频繁。许多大型SNS网站,参与者不一定―网络‖或寻找,以满足新的人,相反,它们是人谁已经扩展社交网络的一部分,他们的主要沟通。为了强调这一点明确的社会网络,这些网站作为一个重要的组织特征,我们将它们标记―社交网站‖。

虽然SNS网站已经实施了各种各样的技术特点,他们的骨干组成可见型材显示铰接式的Friends1谁也系统的用户列表。配置文件是独特的网页,人们可以―输入自己的应运而生‖(松登,2003年,第3页)。在加入一个SNS,一个人被要求填写表格,包含了一系列的问题。回答这些问题,这些问题通常包括描述符,如年龄,位置,兴趣,和一个―关于我‖一节使用该配置文件。大多数网站还鼓励用户上传的个人资料照片。有些网站允许用户添加多媒体内容,或修改他们的个人资料的外观和感觉,以提高他们的档案。其他,如Facebook,允许用户添加模块(―应用程序‖),提高他们的个人资料。

在一个档案中的知名度不同的网站,并根据用户的自由裁量权。默认情况下,型材Friendster和Tribe.net被搜索引擎抓取,使他们的人看到,无论是否观众有一个帐户。另外,LinkedIn的控制的基础上,他或她是否有付费帐户,观众可能会看到什么。像MySpace允许用户来选择他们是否希望他们的个人资料,以成为公众或―朋友只。‖Facebook的一个不同的方法默认情况下,谁是在相同的―网络‖的一部分用户可以查看对方的轮廓,除非一个轮廓所有者已决定拒绝那些在其网络的权限。结构变化的可视性和访问社交网站区别于对方的主要方式之一。

加入一个社交网络站点后,会提示用户识别系统与他们有关系的人在。这些关系的不同而有所不同的标签对网站热门词汇,包括―朋友‖,―联系人‖和―粉丝‖,大多数SNS网站需要双向确认的友谊,但有些则没有。这些单向的关系有时会标示为―粉丝‖或―关注‖,但许多网站称这些朋友。

―朋友‖一词是误导,因为连接并不一定意味着在日常白话感的友谊,人们连接的原因是多种多样的(博伊德,2006A)。

公共显示器的连接是SNS网站的重要组成部分。好友列表中包含链接到每个朋友的个人资料,使观众通过点击好友列表遍历网络图。在大多数网站,好友列表是可见的人谁被允许查看配置文件,但也有例外。例如,一些MySpace的用户已经破解隐藏好友显示他们的个人资料,LinkedIn允许用户选择退出显示其网络。

大多数SNS网站还提供了一种机制,用户朋友的个人资料上留下消息。此功能通常涉及离开―的评论,‖虽然网站使用此功能的各种标签。此外,SNS网站往往有一个私人消息功能类似的webmail。虽然私人消息和评论上流行的主要SNS网站,他们尚未普及。

并非所有的社交网络网站等开始。

QQ作为中国的即时通讯服务,LunarStorm开始作为一个社区网站,赛我网作为韩国的讨论区工具,以及环讯(原Skyblog)的加入SNS功能,是法国前博客服务。

Classmates.com,学校联营公司在1995年推出的一个目录,开始支持SNS网站走红后,铰接式好友列表。在2005-2006年与SNS的功能和结构,然后再重新启动,MiGente AsianAvenue,BlackPlanet早期流行的民族社区网站与好友的功能有限。

虽然SNS网站的设计通常是普及,许多吸引同质人群最初,因此它并不少见找到组使用网站分开自己的国籍,年龄,教育程度,或其他因素,通常段的社会(Hargittai,这个问题)即使那是在没有设计师的意图。字的口碑策略有吸引力,因为他们结合消费者克服阻力显着降低成本和快速的交付,尤其是通过技术,如互联网的前景。不幸的是,目前scantregarding经验证据的相对有效性口碑营销提高企业绩效随着时间的推移。这就提出了一个需要研究企业如何测量WOM通信和口碑如何与其他形式的营销传播效果。

字的口碑营销是互联网上的一个特别突出的特点。互联网为消费者提供了大量的场地,分享自己的观点,喜好,或与别人的经验,以及公司利用口碑营销的机会。正如一位评论家指出,―折腾了数百万美元的超级碗广告,而不是初出茅庐的dot-com公司正试图通过吸引注意力的营销策略,如博客和[口碑]运动‖(2006年,惠特曼B3A页)便宜得多。因此,重要的是要了解是否口碑才是真正有效的,如果是这样,如何与传统营销活动的影响比较。

万维网发展最快的舞台之一是所谓的社交网站的空间。社交网站通常由一小群发送了邀请函,以自己的个人网络的成员加入该网站的创始人发起的。反过来,新的

成员发送邀请到他们的网络,等等。

因此,邀请函(即口碑推荐)网站获得新的成员一直是最重要的推动力。随着社交网站的成熟,他们可能会开始增加他们的传统营销工具的使用。因此,在这个阶段,管理层可能会开始质疑口碑的相对有效性。

本研究的目的是开发和估计一个模型,捕捉新成员收购,口碑转介,与传统营销活动之间的动态关系。在这样做,我们提供一些贡献。

首先,我们之间的第一次直接观察到的口碑链接

吸纳新客户。其次,我们将展示如何配装有口碑与传统营销的措施(例如,增加口碑营销行动的活动,这反过来又增加了新的成员收购)的直接影响和间接影响。我们经验证明,我们的数据集,新加入的会员UPS,这些营销变量之间的内生性。这突出表明,需要考虑到这些间接影响口碑与传统营销的效果,以避免偏估计。第三,我们量化和对比口碑和传统的营销行动,立即和长期弹性。特别是,我们结转效果强的口碑在我们的数据文件。最后,我们估计货币价值附加到每个口碑推荐,提供一个上限的财政奖励管理可能会考虑提供口碑推荐。事实上,这种做法的播种或刺激口碑已迅速增长,但这一活动的有效性仍然很难量化(例如,戈德斯和Mayzlin 2004的)。

我们本文的其余部分组织如下:首先,我们总结前人的研究,以帮助的角度,把我们的贡献。然后,我们描述我们的建模方法。接下来,我们提出了我们的实证分析的数据合作的互联网社交网站,并提供理论和管理者的影响。特别是,我们发现,口碑推荐强烈影响收购新客户,并具有比传统的营销形式由该公司与3至7天(21天)显着较长的结转。我们估计口碑的长期弹性为0.53-约20-30倍,高于传统营销的弹性。

Social Network Sites: Definition, History, and Scholarship

danah m.boyd, Nicole B.Ellison

Journal of Computer-Mediated Communication, Volume 13, Issue 1, pages 210–230, October 2007

Social Network Sites: Definition We define social network sites as web-based services that allow individuals to(1)construct a public or semi-public profile within a bounded system,(2)articulate a list of other users with whom they share a connection, and(3)view and traverse their list of connections and those made by others within the system.The nature and nomenclature of these connections may vary from site to site.While we use the term ―social network site‖ to describe this phenomenon, the term ―social networking sites‖ also appears in public discourse, and the two terms are often used interchangeably.We chose not to employ the term ―networking‖ for two reasons: emphasis and scope.―Networking‖ emphasizes relationship initiation, often between strangers.While networking is possible on these sites, it is not the primary practice on many of them, nor is it what differentiates them from other forms of computer-mediated communication(CMC).What makes social network sites unique is not that they allow individuals to meet strangers, but rather that they enable users to articulate and make visible their social networks.This can result in connections between individuals that would not otherwise be made, but that is often not the goal, and these meetings are frequently between ―latent ties‖(Haythornthwaite, 2005)who share some offline connection.On many of the large SNSs, participants are not necessarily ―networking‖ or looking to meet new people;instead, they are primarily communicating with people who are already a part of their extended social network.To emphasize this articulated social network as a critical organizing feature of these sites, we label them ―social network sites.‖

While SNSs have implemented a wide variety of technical features, their backbone consists of visible profiles that display an articulated list of Friends1 who are also users of the system.Profiles are unique pages where one can ―type oneself into being‖(Sundén, 2003, p.3).After joining an SNS, an individual is asked to fill out forms containing a series of questions.The profile is generated using the answers to these questions, which typically include descriptors such as age, location, interests, and an ―about me‖ section.Most sites also encourage users to upload a profile photo.Some sites allow users to enhance their profiles by adding multimedia content or modifying their profile’s look and feel.Others, such as Facebook, allow users to add modules(―Applications‖)that enhance their profile.The visibility of a profile varies by site and according to user discretion.By default, profiles on Friendster and Tribe.net are crawled by search engines, making them visible to anyone, regardless of whether or not the viewer has an account.Alternatively, LinkedIn controls what a viewer may see based on whether she or he has a paid account.Sites like MySpace allow users to choose whether they want their profile to be public or ―Friends only.‖ Facebook takes a different approach—by default, users who are part of the same ―network‖ can view each other’s profiles, unless a profile owner has decided to deny permission to those in their network.Structural variations around visibility and access are one of the primary ways that SNSs differentiate themselves from each other.After joining a social network site, users are prompted to identify others in the system with whom they have a relationship.The label for these relationships differs depending on the site—popular terms include ―Friends,‖―Contacts,‖ and ―Fans.‖ Most SNSs require bi-directional confirmation for Friendship, but some do not.These one-directional ties are sometimes labeled as ―Fans‖ or ―Followers,‖ but many sites call these Friends as well.The term ―Friends‖ can be misleading, because the connection does not necessarily mean friendship in the everyday vernacular sense, and the reasons people connect are varied(boyd, 2006a).The public display of connections is a crucial component of SNSs.The Friends list contains links to each Friend’s profile, enabling viewers to traverse the network graph by clicking through the Friends lists.On most sites, the list of Friends is visible to anyone who is permitted to view the profile, although there are exceptions.For instance, some MySpace users have hacked their profiles to hide the Friends display, and LinkedIn allows users to opt out of displaying their network.Most SNSs also provide a mechanism for users to leave messages on their Friends’ profiles.This feature typically involves leaving ―comments,‖ although sites employ various labels for this feature.In addition, SNSs often have a private messaging feature similar to webmail.While both private messages and comments are popular on most of the major SNSs, they are not universally available.Not all social network sites began as such.QQ started as a Chinese instant messaging service, LunarStorm as a community site, Cyworld as a Korean discussion forum tool, and Skyrock(formerly Skyblog)was a French blogging service before adding SNS features.Classmates.com, a directory of school affiliates launched in 1995, began supporting articulated lists of Friends after SNSs became popular.AsianAvenue, MiGente, and BlackPlanet were early popular ethnic community sites with limited Friends functionality before re-launching in 2005–2006 with SNS features and structure.While SNSs are often designed to be widely accessible, many attract homogeneous populations initially, so it is not uncommon to find groups using sites to segregate themselves by nationality, age, educational level, or other factors that typically segment society(Hargittai, this issue), even if that was not the intention of the designers.Word-of-mouth communication strategies are appealing because they combine the prospect of overcoming consumer resistance with significantly lower costs and fast delivery—especially through technology, such as the Internet.Unfortunately, empirical evidence is currently scantregarding the relative effectiveness of WOM marketing in increasing firm performance over time.This raises the need to study how firms can measure the effects of WOM communications and how WOM compares with other forms of marketing communication.Word-of-mouth marketing is a particularly prominent feature on the Internet.The Internet provides numerous venues for consumers to share their views, preferences, or experiences with others, as well as opportunities for firms to take advantage of WOM marketing.As one commentator stated, ―Instead of tossing away millions of dollars on Superbowl advertisements, fledgling dot-com companies are trying to catch attention through much cheaper marketing strategies such as blogging and [WOM] campaigns‖(Whitman 2006, p.B3A).Thus, it is important to understand whether WOM is truly effective and, if so, how its impact compares with traditional marketing activities.One of the fastest-growing arenas of the World Wide Web is the space of so-called social networking sites.A social networking site is typically initiated by a small group of founders who send out invitations to join the site to the members of their own personal networks.In turn, new members send invitations to their networks, and so on.Thus, invitations(i.e., WOM referrals)have been the foremost driving force for sites to acquire new members.As social networking sites mature, they may begin to increase their use of traditional marketing tools.Therefore, management may begin to question the relative effectiveness of WOM at this stage.The objective of this research is to develop and estimate a model that captures the dynamic relationships among new member acquisition, WOM referrals, and traditional marketing activities.In doing so, we offer several contributions.First, we are among the first to link observed WOM directly to new customer acquisition.Second, we show how toincorporate both the direct effects and the indirect effects of WOM and traditional marketing actions(e.g., a marketing action increases WOM activity, which in turn increases new member acquisition).We empirically demonstrate, for our data set, the endogeneity among new member sign-ups and these marketing variables.This highlights the need to account for these indirect effects to avoid biased estimates for both WOM and traditional marketing effects.Third, we quantify and contrast the immediate and long-term elasticities of WOM and traditional marketing actions.In particular, we document strong carryover effects for WOM in our data.Finally, we attach an estimated monetary value to each WOM referral, providing an upper bound to the financial incentive management might consider offering for WOM referrals.Indeed, the practice of seeding or stimulating WOM has grown rapidly, but quantifying the effectiveness of this activity remains difficult(e.g., Godes and Mayzlin 2004).We organize the remainder of this article as follows: We begin by summarizing previous research to help put our contributions in perspective.We then describe our modeling approach.Next, we present our empirical analysis of the data from a collaborating Internet social networking site and offer implications for theory and managers.In particular, we find that WOM referrals strongly affect new customer acquisitions and have significantly longer carryover than traditional forms of marketing used by the firm(21 days versus 3 to 7 days).We estimate a long-term elasticity for WOM of.53—approximately 20–30 times higher than the elasticities for traditional marketing.

第五篇:外文翻译

微孔的加工方法

正如宏观加工一样,在微观加工中孔的加工也许也是最常用的加工之一。孔的加工方法有很多种,每一种都有其优点和缺点,这主要取决于孔的直径、深度、工作材料和设备要求。这篇文章主要介绍了内冷却钻头钻孔、无冷却钻孔、插铣、电火花以及激光加工微孔的几种方法。

易于孔加工的操作

无论孔有多大,在加工时将冷却液导入到刀尖,这都有助于排屑并能降低刀具和工件表面产生的摩擦热。尤其是在加工深细孔时,有无冷却液对加工的影响更大,因为深细孔加工的刀具比较脆弱,再加上刀具对切屑的二次切削和切屑的堆积会积累大量的热,而热量是碳化物刀具的主要“天敌”,它会加快刀具的失效速度。

当使用外冷却液时,刀具本身会阻止切削液进入切削加工位置。也就是到3-5倍的直径深度后切削液就会很难流入到刀尖。副哈维工具有限公司的副总工程师杰夫戴维斯说,这时就该选用带有内冷却液的钻头。

另外,在加工小孔时采用的外冷却液的冷却方式产生的利要大于弊,当钻头进入工件时,已经流入孔的冷却液产生的压力有时会缴坏钻头,戴维斯说。

刀具生产商提供的标准钻头的直径从0.039到 0.125英寸,能加工深度小雨12倍的直径的深孔,同时提供直径从0.002到0.020英寸的不带内冷却液的钻头。

尽管有内冷却能力,但还是不够的,冷却液需要一定的流动速度从而能够将切屑清出孔外。戴维斯强调,冷却液的最低压力应为600-800磅/平方英寸,加工状况还会随着所施加的压力的增加而提高,他补充道。

为了防止这些冷却液通口被杂物堵塞,戴维斯还推荐在钻头加上一5微米孔径或更加精密的冷却液滤清器。

另外,他还推荐在加工孔时有必要在工件的上方先技工一个定心或导向孔,以防止刀具偏斜,并有助于保证所加工孔的垂直度。当选用定心钻时,应使选择的定心钻刀尖上的坡口角小于等于其后内冷钻的坡口角。定心钻的直径还要稍微大一些。例如,如果定心钻的坡口角为120,内冷却钻头的坡口角为140,并且定心钻的直径小于内冷却钻的直径。在加工时内冷却钻的拐角处会与定心孔干涉而容易脱落,戴维斯说:这将导致钻头损坏。

虽然没加强调,但是加工细深孔时,喙式进给是一种很好的加工方式。戴维斯建议,根据工件的材料不同。每次喙式进给的深度最好为孔径的30%--50%。这种加工方式便于排出切屑,使切屑不在加工孔中堆积。润滑及冷却

为了更加有助于徘屑,戴维斯推荐在金属加工中使用油基金属切削液代替水基冷却液,因为油具有较高的润滑效果。但是如果车间更加青睐于使用水基冷却液,液体中应该包括EP(极压)添加剂,增加润滑和减少发泡。如果产生很多泡沫,戴维斯说,“切屑就不会按着预定的方式排出。”

他还补充道,另一种提高润滑并且提高刀具寿命的方法是道具涂层,例如氮铝化钛(TiAIN)。TiAIN具有很高的硬度,当钻削像不锈钢这样的难加工金属材料时,带有TiAIN涂层的刀具能有效的减少热冲击。

威斯康星洲简斯维尔微型刀具公司的总经理大卫伯顿,对微加工刀具的小批量涂层有不同的看法,他说:“对直径小于0.020英寸的刀具涂层,会对刀具的加工质量到刀具寿命等每一加工方面都产生消极影响”。因为小刀具涂层不能做的足够薄,这样涂层就会改变刀具的前角和后角,从而不利于加工。

不过,更薄的涂层的开发正在继续,伯顿表示,现在微型刀具公司除了生产销售微型铣刀、刨刀和微型钻头外,还在和其他公司合作致力于开发一种亚细微涂层。伯顿说:“我们计划这种涂层刀君会在六月到一年的时间内上市”。

微型钻公司的产品主要是用于电路板加工钻头,但也可用于有效的切屑金属。所有的刀具都没带内冷能力。“我有一个客户想要在不锈钢上面钻一个0.004英寸的孔,他当时非常惊讶这能用一把加工电路板的钻头完成”。伯顿还补充到,采用喙式进给并选择高的主轴速度可以提高钻头的效率。

微加工刀具要使用多高的转速,这主要依赖于车间所使用的数控机床和刀具的直径,所需的转速随刀具直径的增加而加快(注:切削速度公式为 sfm=刀具直径×0.26×主轴转速)。

虽然相对较低,但伯顿的客户也成功 的应用过每分钟5000转的加工速度。伯顿说:“我们建议我们的用户找到一个震动最小的最高转速-----最佳加工速度。”

为了减少震动,在用小的切削力通过刀具的前倾面的去除适当的金属时,应使渗入到工件中的切削载荷连续而充足,如果钻头承受的切削载荷太轻,刀具前倾面的磨损速度就会加快,刀具变钝,从而影响刀具的使用寿命。这在加工细孔时应更加注意。

“用户们常常使用较轻的切削载荷来延长刀具的使用寿命,”伯顿说,“这恰恰会加快切削刃的磨损,并在刀刃宽出切屑的位置形成圆弧,刀具会变得像磨削工具一样把材料强行除掉,只能成为废刀。”伯顿认为,直径大于0.001英寸的刀具切削抗力小于0.0001时,切削力抗力就已经太小了,即使刀具不会断裂,过早的摩擦也会导致刀具寿命缩短。

太多的跳动也可能是破坏性的,但是影响有多少还值得商榷。伯顿指出,公司打算设计一台具有0.0003英寸偏差的机器,用以建立室内最坏情况下的铣削场景,还将能够加工0.004英寸宽的槽。“这迟早会实现的”。

他还补充:“你还可以试想一下0.0003英寸的跳动和只有正常水平三分之一的切削载荷,也就是说0.0001到0.00015,刀具将会立即破坏,因为刀具的一个徘屑槽会承受所有的载荷,然后徘屑槽的后面就会破坏。”

他还指出,在钻孔时,小于0.0003英寸的偏差是可以接受的,因为当钻头深入孔内时,钻头末端的切削刃在外圆柱非加工表面的引导下会继续切削。偏差的最小值随着深度和直径比值的增加而迅速减少,这是因为当钻头越深入工件,徘屑槽的吸震能力越差。最后强烈的跳动导致刀柄绕着刀具的轴线转动,而刀尖还仍然保持稳定,从而产生是刀具最终断裂的集中应力。插铣

虽然通常没有直径小于0.002英寸的标准微型钻头,但可以用微型端铣刀来“冲”孔。“每当人们想加工一个小于0.002英寸的孔时,他们可以选用端铣刀,效果也不错。”伯顿说道。但这样加工的孔不能太深,因为刀具体不长,没有大的深度直径比率,因此一把直径为0.001英寸的端铣刀只能加工最深0.20英寸的孔,而同样直径的钻头可以加工得更深,因为钻头的设计使载荷全部作用在刀尖上,进而传到刀柄上被吸收。

市面上能提供最小5微米的端铣刀,但是并没有大量销售。“当人们想买这样的刀具时,我非常严肃的试着说服他们不要买,因为我们不喜欢制作这样的刀具。”伯顿说到。这种刀具主要问题是。不但这种刀具的硬质合金齿处于亚细微尺寸,而且当一把刀有多个齿时,每个齿的尺寸还要保持一致。伯顿道:“一把直径5微米的端铣刀在其基体上就夹持大约10个刀齿。”

他还补充说,他曾经看到过带有0.微米的粉末冶金硬质合金刀具,这是商业上能提供齿的尺寸的一半,但它还包括0.5和0.6微米的小齿。“如果齿的尺寸不统一,小齿是发挥不出作用的。” 坠电火花加工

应用坠电火花的电火花加工是一种微孔加工方式。这不同于将电导线穿过工件的电火花加工方式,应用坠电火花加工的微孔更加精密和精确,但同时花费也会很高。

坠电火花加工深细孔时,要用一根导电管作为电极。加工小而浅的孔时,需要用到一根导线或棒,“我们尽量用导管做电极。位于密歇根州的牧野公司总经理Jeff Kiszonas说道,导管的排渣孔能使加工的孔有大的深度直径比,并能够在加工中将孔底的熔渣排出孔外。他又补充道”但是另一方面,没人能制造出小于一定直径的导管。“一些供应商能提供直径小于0.003英寸的导管可以加工出0.0038英寸的孔。

现在Makino公司生产的双边坠电火花加工设备能够加工出 0.00044 英寸的微孔,这种设备主要用于孔的精加工。最近,在日本这种机床的开发人员用两分钟加工了八个这样的孔,并用四十秒穿透了0.0010英寸厚的碳化钨板。加工电极为一个因钨合金棒,由于电火花加工中再电极和工件间存在放电间隙,所以,所加工孔的直径会比电极直径大0.00020英寸。

当加工上述尺寸的孔时,旋转的导棒上包裹着通电的放电导线。精加工时需要一个w轴附件,用来夹持电极导向的模具,另外还需要一个中间导向件,当电极旋转时用来防止其弯曲和摆动。应用这种加工方式的机床适合于加工直径小于0.005英寸的孔。

另一种坠电火花加工微型孔机床是三菱VA10机床,它用精加工孔的钻摸附件来装卡和引导精制导线来腐蚀金属,伊利诺伊州的MC机械系统公司产品加工经理丹尼斯德利说:“这是一种标准的电火花加工,但是借助于安装在机器上的附件,我们同样可以加工细孔”。他还补充说在电火花加工中用2000转/分的转速旋转的导线可以加工小于0.0004英寸的孔。钨电极电火花加工

电火花加工是一中典型的慢加工,加工微孔时这表现得也很明显。“电火花加工非常慢,并且随着加工精度的增加而减慢”Midvale公司(Midvale公司是一个位于犹他州,主要生产24伏低电压电火花加工设备和基于精密电火花加工的公司)的总裁迪恩约根森说。

钨电极的生产是应用反极性接法,经机械加工、研磨加工使之直径达到10微米、粗糙度为0.000020英寸。应用1-微米的电极加工10.5到11微米的孔,并能加工盲孔。用于加工最小孔的最大工件厚度为0.002英寸,加工50微米直径的孔时工件的厚度能达到0.004英寸。

在激光加工之后用电火花加工是生产高精度孔的一种比较不错的方法,约根森已经决定重新研发最好的加工设备。“我们需要重新研发所有电子控件、程序软件和机械”。约根森说重新研发这些软件和继续额需要花费180000到200000美元。

车间里多数精加工为100美元/小时,包括特殊金属的电火花加工,如:X射线加工金和铂、光加工不锈钢、阴极射线加工钨和钽。约根森说道,电火花加工还不适合加工半导体材料,如聚晶金刚石。光加工

除了硬质合金和钨电极外,光也是一个不错的微孔加工的“刀具”材料。虽然大多数来钻孔的激光都是处于红外光谱范围,但是根据宾尼法尼亚州的Ex One Co。、Iiwin公司的激光技术主管兰迪吉尔摩介绍,他们采用的是绿色光柱的超脉冲技术。不像其他种类的微加工光束,超脉冲是一种纳秒级激光,它绿色光束的波长为532纳米。这种技术产生的激光一对脉冲时间为4到5纳秒,每对脉冲的间隔为50到100纳秒。这种技术的加工方式成倍的提高了加工效率。“与其他激光加工相比,这种技术大大的提高了金属去除率”。吉尔摩说:“由于这种激光脉冲短,所以很大程度上减少了对工件材料的热损伤。”

超脉冲激光加工孔的最小直径为45微米,不过这种加工最常用在H系列钢材料的柴油机喷嘴90微米到110微米孔的加工。吉尔摩提到,根据排放标准的要求这种孔的直径要缩小到50微米到70微米,因为越小的孔越能使燃料充分燃烧。

另外,这种技术加工的孔还带有一个负的锥度,就是入口直径小于出口直径,这有利于燃料的流动。

这种技术的另一种常用的应用是在航空涡轮叶片上打冷却孔。虽然叶轮只有1.5mm到2mm厚,但吉尔摩解释说,这种孔要带有25°的入口倾角,以使冷空气贴着孔壁流动,更好的起到冷却作用,这就是说钻孔的长度达到5mm。他说:“温度是航空发动机的主宰,叶轮运行的环境温度越高,燃料的利用率越高,得到的推力越大。

为了加强这技术的竞争力,Ex One 公司研发了一种专利材料,将这种材料注入中空的部件体内,可以防止光柱所加工孔以下壁体的烧伤。光加工之后,可以将这种材料完全清理掉。

“光加工的一种缺点是,光柱在遇到另一个实体之前就会一直传播”吉尔摩说:“加工柴油机喷嘴时,这会损坏相对壁的内表面”。

超脉冲加工设备的价格为650000到800000美元,虽然这要高于电火花加工设备,但是光加工不会用到电极。“激光加工用光做刀具”吉尔摩说:“它节省了电极的开支”。

根据其应用的不同,机械钻削加工、插铣、电火花加工和光加工在微孔加工中都占有一席之地。牧野公司的Kiszonas说:“用户也比较向往有更多的微孔加工方法供其选择”。

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