第一篇：11畢業(yè)設(shè)計論文外文翻譯封面

長江大學(xué)工程技術(shù)學(xué)院

畢業(yè)設(shè)計（論文）外文翻譯

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第二篇：9、畢業(yè)設(shè)計(論文)外文資料翻譯封面格式

南京工程學(xué)院

畢業(yè)設(shè)計(論文)外文資料翻譯

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第三篇：畢業(yè)設(shè)計(論文)外文翻譯(原文)

畢業(yè)設(shè)計（論文）——外文翻譯（原文）

NEWAPPLICATIONOFDATABASE

Relational databases have been in use for over two decades.A large portion of the applications of relational databases have been in the commercial world, supporting such tasks as transaction processing for banks and stock exchanges, sales and reservations for a variety of businesses, and inventory and payroll for almost of all companies.We study several new applications, which have become increasingly important in recent years.First.Decision-support system

As the online availability of data has grown, businesses have begun to exploit the available data to make better decisions about increase sales.We can extract much information for decision support by using simple SQL queries.Recently however, people have felt the need for better decision support based on data analysis and data mining, or knowledge discovery, using data from a variety of sources.Database applications can be broadly classified into transaction processing and decision support.Transaction-processing systems are widely used today, and companies have accumulated a vast amount of information generated by these systems.The term data mining refers loosely to finding relevant information, or “discovering knowledge,” from a large volume of data.Like knowledge discovery in artificial intelligence, data mining attempts to discover statistical rules and patterns automatically from data.However, data mining differs from machine learning in that it deals with large volumes of data, stored primarily on disk.Knowledge discovered from a database can be represented by a set of rules.We can discover rules from database using one of two models:

In the first model, the user is involved directly in the process of knowledge discovery.In the second model, the system is responsible for automatically discovering knowledge from the database, by detecting patterns and correlations in the data.Work on automatic discovery of rules has been influenced strongly by work in the artificial-intelligence community on machine learning.The main differences lie in the volume of data handled in databases, and in the need to access disk.Specialized data-mining algorithms have been developed to handle large volumes of disk-resident data efficiently.The manner in which rules are discovered depends on the class of data-mining application.We illustrate rule discovery using two application classes: classification and associations.Second.Spatial and Geographic Databases

Spatial databases store information related to spatial locations, and provide support for efficient querying and indexing based on spatial locations.Two types of spatial databases are particularly important:

Design databases, or computer-aided-design(CAD)databases, are spatial databases used to store design information about how objects---such as buildings, cars or aircraft---are constructed.Other important examples of computer-aided-design databases are integrated-circuit and electronic-device layouts.Geographic databases are spatial databases used to store geographic information, such as maps.Geographic databases are often called geographic information systems.Geographic data are spatial in nature, but differ from design data in certain ways.Maps and satellite images are typical examples of geographic data.Maps may provide not only location information-such

as boundaries, rivers and roads---but also much more detailed information associated with locations, such as elevation, soil type, land usage, and annual rainfall.Geographic data can be categorized into two types: raster data(such data consist a bit maps or pixel maps, in two or more dimensions.), vector data(vector data are constructed from basic geographic objects).Map data are often represented in vector format.Third.Multimedia Databases

Recently, there has been much interest in databases that store multimedia data, such as images, audio, and video.Today multimedia data typically are stored outside the database, in files systems.When the number of multimedia objects is relatively small, features provided by databases are usually not important.Database functionality becomes important when the number of multimedia objects stored is large.Issues such as transactional updates, querying facilities, and indexing then become important.Multimedia objects often have descriptive attributes, such as those indicating when they were created, who created them, and to what category they belong.One approach to building a database for such multimedia objects is to use database for storing the descriptive attributes, and for keeping track of the files in which the multimedia objects are stored.However, storing multimedia outside the database makes it harder to provide database functionality, such as indexing on the basis of actual multimedia data content.It can also lead to inconsistencies, such a file that is noted in the database, but whose contents are missing, or vice versa.It is therefore desirable to store the data themselves in the database.Forth.Mobility and Personal Databases

Large-scale commercial databases have traditionally been stored in central computing facilities.In the case of distributed database applications, there has usually been strong central database and network administration.Two technology trends have combined to create applications in which this assumption of central control and administration is not entirely correct:

1.The increasingly widespread use of personal computers, and, more important, of laptop or “notebook” computers.2.The development of a relatively low-cost wireless digital communication infrastructure, base on wireless local-area networks, cellular digital packet networks, and other technologies.Wireless computing creates a situation where machines no longer have fixed locations and network addresses.This complicates query processing, since it becomes difficult to determine the optimal location at which to materialize the result of a query.In some cases, the location of the user is a parameter of the query.A example is a traveler’s information system that provides data on hotels, roadside services, and the like to motorists.Queries about services that are ahead on the current route must be processed based on knowledge of the user’s location, direction of motion, and speed.Energy(battery power)is a scarce resource for mobile computers.This limitation influences many aspects of system design.Among the more interesting consequences of the need for energy efficiency is the use of scheduled data broadcasts to reduce the need for mobile system to transmit queries.Increasingly amounts of data may reside on machines administered by users, rather than by database administrators.Furthermore, these machines may, at times, be disconnected from the network.Summary

Decision-support systems are gaining importance, as companies realize the value of the on-line data collected by their on-line transaction-processing systems.Proposed extensions to SQL, such as the cube operation, help to support generation of summary data.Data mining seeks to discover

knowledge automatically, in the form of statistical rules and patterns from large databases.Data visualization systems help humans to discover such knowledge visually.Spatial databases are finding increasing use today to store computer-aided design data as well as geographic data.Design data are stored primarily as vector data;geographic data consist of a combination of vector and raster data.Multimedia databases are growing in importance.Issues such as similarity-based retrieval and delivery of data at guaranteed rates are topics of current research.Mobile computing systems have become common, leading to interest in database systems that can run on such systems.Query processing in such systems may involve lookups on server database.畢業(yè)設(shè)計（論文）——外文翻譯（譯文）

數(shù)據(jù)庫的新應(yīng)用

我們使用關(guān)系數(shù)據(jù)庫已經(jīng)有20多年了，關(guān)系數(shù)據(jù)庫應(yīng)用中有很大一部分都用于商業(yè)領(lǐng)域支持諸如銀行和證券交易所的事務(wù)處理、各種業(yè)務(wù)的銷售和預(yù)約，以及幾乎所有公司都需要的財產(chǎn)目錄和工資單管理。下面我們要研究幾個新的應(yīng)用，近年來它們變得越來越重要。

1、決策支持系統(tǒng)

由于越來越多的數(shù)據(jù)可聯(lián)機(jī)獲得，企業(yè)已開始利用這些可獲得的數(shù)據(jù)來對自己的行動做出更好的決策，比如進(jìn)什么貨，以及如何最好的吸引顧客以提高銷售額。我們可以通過使用簡單的SQL查詢語句提供大量用于決策支持的信息。但是，人們最近感到需要使用多種數(shù)據(jù)源的數(shù)據(jù)，以便在數(shù)據(jù)分析和數(shù)據(jù)挖掘（或知識發(fā)現(xiàn)）的基礎(chǔ)上，更好的來做決策支持。

數(shù)據(jù)庫應(yīng)用從廣義上可分為事務(wù)處理和決策支持兩類。事務(wù)處理系統(tǒng)現(xiàn)在正被廣泛使用，并且公司已經(jīng)積累了大量由這類系統(tǒng)產(chǎn)生的信息。

數(shù)據(jù)挖掘這個概念廣義上講是指從大量數(shù)據(jù)中發(fā)現(xiàn)有關(guān)信息，或“發(fā)現(xiàn)知識”。與人工智能中的知識發(fā)現(xiàn)類似，數(shù)據(jù)挖掘試圖自動從數(shù)據(jù)中發(fā)現(xiàn)統(tǒng)計規(guī)則和模式。但是，數(shù)據(jù)挖掘和機(jī)器學(xué)習(xí)的不同在于它處理的是大量數(shù)據(jù)，它們主要存儲在磁盤上。

從數(shù)據(jù)庫中發(fā)現(xiàn)的知識可以用一個規(guī)則集表示。我們用如下兩個模型之一從數(shù)據(jù)庫中發(fā)現(xiàn)規(guī)則：

● 在第一個模型中，用戶直接參與知識發(fā)現(xiàn)的過程

● 在第二個模型中，系統(tǒng)通過檢測數(shù)據(jù)的模式和相互關(guān)系，自動從數(shù)據(jù)庫中發(fā)現(xiàn)知識。有關(guān)自動發(fā)現(xiàn)規(guī)則的研究很大程度上是受人工智能領(lǐng)域在知識學(xué)習(xí)方面研究的影響。其主要的區(qū)別在于數(shù)據(jù)庫中處理的數(shù)據(jù)量，以及是否需要訪問磁盤。已經(jīng)有一些具體的數(shù)據(jù)挖掘算法用于高效地處理放在磁盤上的大量數(shù)據(jù)。

規(guī)則發(fā)現(xiàn)的方式依賴于數(shù)據(jù)挖掘應(yīng)用的類型。我們用兩類應(yīng)用闡述規(guī)則發(fā)現(xiàn)：分類和關(guān)聯(lián)。

2、空間和地理數(shù)據(jù)庫

空間數(shù)據(jù)庫存儲有關(guān)空間位置的信息，并且對高效查詢和基于空間位置的索引提供支持。有兩種空間數(shù)據(jù)庫特別重要：

● 設(shè)計數(shù)據(jù)庫或計算機(jī)輔助設(shè)計（CAD）數(shù)據(jù)庫是用于存儲設(shè)計信息的空間數(shù)據(jù)庫，這些信息主要是關(guān)于物體（如建筑、汽車或是飛機(jī)）是如何構(gòu)造的。另一個計算機(jī)輔助設(shè)計數(shù)據(jù)庫的重要例子是整合電路和電子設(shè)備設(shè)計圖。

● 地理數(shù)據(jù)庫是用于存儲地理信息（如地圖）的空間數(shù)據(jù)庫。地理數(shù)據(jù)庫常稱為地理信息系統(tǒng)。

地理數(shù)據(jù)本質(zhì)上是空間的，但與設(shè)計數(shù)據(jù)相比在幾個方面有所不同。地圖和衛(wèi)星圖像是地理數(shù)據(jù)的典型例子。地圖不僅可提供位置信息，如邊界、河流和道路，而且還可以提供許多和位置相關(guān)的詳細(xì)信息，如海拔、土壤類型、土地使用和年降雨量。地理數(shù)據(jù)可以分為兩類：光柵數(shù)據(jù)（這種數(shù)據(jù)由二維或更高維的位圖或像素圖組成）、矢量數(shù)據(jù)（由基本幾何對象構(gòu)成）。地圖數(shù)據(jù)常以矢量形式表示。

3、多媒體數(shù)據(jù)庫

最近，有關(guān)多媒體數(shù)據(jù)（如圖像、聲音和視頻）的數(shù)據(jù)庫的研究很熱門。現(xiàn)在多媒體數(shù)據(jù)通常存儲在數(shù)據(jù)庫以外的文件系統(tǒng)中。當(dāng)多媒體對象的數(shù)目相對較少時，數(shù)據(jù)庫提供的特點往往不那么重要。但是當(dāng)存儲的多媒體對象數(shù)目較多時，數(shù)據(jù)庫的功能就變得重要起來?？傊?，事務(wù)更新、查詢機(jī)制和索引也開始變的很重要。多媒體對象常常有描述屬性，如指明它們是何時創(chuàng)建的、誰創(chuàng)建的，以及它們屬于哪一類。構(gòu)造這種多媒體對象的數(shù)據(jù)庫的方法之一是用數(shù)據(jù)存儲描述屬性，并且跟蹤存儲這些媒體對象的文件。

但是，將多媒體數(shù)據(jù)存儲在數(shù)據(jù)庫之外，使得難于提供數(shù)據(jù)庫的功能，譬如基于實際多媒體數(shù)據(jù)內(nèi)容的索引。此外這種情況還會造成不一致，譬如一個文件在數(shù)據(jù)庫中做了記錄，但其內(nèi)容卻丟失了；或其相反情況。因此我們更希望將數(shù)據(jù)本身存儲在數(shù)據(jù)庫中。

4、移動性和個人數(shù)據(jù)庫

大型商用數(shù)據(jù)庫傳統(tǒng)上是存儲在中央計算設(shè)備上的。在分布式數(shù)據(jù)庫應(yīng)用中，通常有強(qiáng)大的中央數(shù)據(jù)庫和網(wǎng)絡(luò)管理。然而以下這兩個技術(shù)趨勢的結(jié)合產(chǎn)生了一些應(yīng)用，這些應(yīng)用使中央控制和管理不再完全正確：

● 個人計算機(jī)越來越廣泛的使用，其中更重要的 是便攜式或“筆記本”計算機(jī)的使用?！?基于無限局域網(wǎng)、蜂窩數(shù)字包網(wǎng)絡(luò)，以及其他技術(shù)成本相對低廉的無線數(shù)字通信基礎(chǔ)設(shè)

施的發(fā)展。

無線計算使得計算機(jī)不必有固定的位置和網(wǎng)絡(luò)地址這使得查詢處理更加復(fù)雜，因為它難于決定實體化查詢結(jié)果的最佳位置。某些情況下，用戶的位置是一個查詢參數(shù)。例如，一個旅客信息系統(tǒng)提供關(guān)于酒店、路邊服務(wù)的信息及類似信息給乘車的旅客。有關(guān)當(dāng)前道路前放服務(wù)的查詢必須根據(jù)用戶的位置、移動的方向及速度進(jìn)行處理。

能源（電池能源）對應(yīng)動計算機(jī)來說是有限的資源，這一限制影響了系統(tǒng)設(shè)計的許多方面。能源效率需求最有趣的結(jié)果之一的使用計劃的數(shù)據(jù)廣播來減少傳輸查詢中移動系統(tǒng)的需求。越來越多的數(shù)據(jù)會放在由用戶管理、而不是由數(shù)據(jù)庫管理員管理的計算機(jī)上，并且這些計算機(jī)有時可能與網(wǎng)絡(luò)斷開連接。

5、總結(jié)

隨著企業(yè)認(rèn)識到聯(lián)機(jī)事務(wù)處理系統(tǒng)收集的聯(lián)機(jī)數(shù)據(jù)的價值，決策支持系統(tǒng)也越發(fā)變得重要了?，F(xiàn)已提出SQL擴(kuò)展，如cube操作，能幫助系統(tǒng)生成匯總數(shù)據(jù)。數(shù)據(jù)挖掘致力于從大數(shù)據(jù)庫中自動發(fā)現(xiàn)統(tǒng)計規(guī)律和模式等知識。數(shù)據(jù)可視化系統(tǒng)幫助人們從視覺上發(fā)現(xiàn)這些知識。

目前，空間數(shù)據(jù)庫正越來越多的被應(yīng)用于存儲計算機(jī)輔助設(shè)計數(shù)據(jù)和地理數(shù)據(jù)。設(shè)計數(shù)據(jù)基本上是以矢量數(shù)據(jù)的形式存儲，而地理數(shù)據(jù)則包含矢量數(shù)據(jù)和光柵數(shù)據(jù)。

多媒體數(shù)據(jù)庫正變得越來越重要。基于相似性的查詢以及按可以確保的速率傳送數(shù)據(jù)是當(dāng)前研究的重要課題。

移動計算系統(tǒng)的普及使人們對這類系統(tǒng)上運(yùn)行的數(shù)據(jù)庫產(chǎn)生了濃厚的興趣。在這類系統(tǒng)上的查詢處理可能會設(shè)計在服務(wù)器端數(shù)據(jù)庫上的查找。

第四篇：畢業(yè)設(shè)計外文翻譯

外文原文

Overview of JSp Technology

Benefits of JSp

JSp pages are translated into servlets.So, fundamentally, any task JSp pages can perform could also be accomplished by servlets.However, this underlying equivalence does not mean that servlets and JSp pages are equally appropriate in all scenarios.The issue is not the power of the technology, it is the convenience, productivity, and maintainability of one or the other.After all, anything you can do on a particular computer platform in the Java programming language you could also do in assembly language.But it still matters which you choose.JSp provides the following benefits over servlets alone:

?It is easier to write and maintain the HTML.Your static code is ordinary HTML: no extra backslashes, no double quotes, and no lurking Java syntax.?You can use standard Web-site development tools.Even HTML tools that know nothing about JSp can be used because they simply ignore the JSp tags.?You can divide up your development team.The Java programmers can work on the dynamic code.The Web developers can concentrate on the presentation layer.On large projects, this division is very important.Depending on the size of your team and the complexity of your project, you can enforce a weaker or stronger separation between the static HTML and the dynamic content.Now, this discussion is not to say that you should stop using servlets and use only JSp instead.By no means.Almost all projects will use both.For some requests in your project, you will use servlets.For others, you will use JSp.For still others, you will combine them with the MVC architecture.You want the appropriate tool for the job, and servlets, by themselves, do not complete your toolkit.Advantages of JSp Over Competing Technologies

A number of years ago, Marty was invited to attend a small 20-person industry roundtable discussion on software technology.Sitting in the seat next to Marty was James Gosling, inventor of the Java programming language.Sitting several seats away was a high-level manager from a very large software company in Redmond, Washington.During the discussion, the moderator brought up the subject of Jini, which at that time was a new Java technology.The moderator asked the manager what he thought of it, and the manager responded that it was too early to tell, but that it seemed to be an excellent idea.He went on to say that they would keep an eye on it, and if it seemed to be catching on, they would follow his company's usual “embrace and extend” strategy.At this point, Gosling lightheartedly interjected “You mean disgrace and distend.”

Now, the grievance that Gosling was airing was that he felt that this company would take technology from other companies and suborn it for their own purposes.But guess what? The shoe is on the other foot here.The Java community did not invent the idea of designing pages as a mixture of static HTML and dynamic code marked with special tags.For example, ColdFusion did it years earlier.Even ASp(a product from the very software company of the aforementioned manager)popularized this approach before JSp came along and decided to jump on the bandwagon.In fact, JSp not only adopted the general idea, it even used many of the same special tags as ASp did.So, the question becomes: why use JSp instead of one of these other technologies? Our first response is that we are not arguing that everyone should.Several of those other technologies are quite good and are reasonable options in some situations.In other situations, however, JSp is clearly better.Here are a few of the reasons.Versus.NET and Active Server pages(ASp)

.NET is well-designed technology from Microsoft.ASp.NET is the part that directly competes with servlets and JSp.The advantages of JSp are twofold.First, JSp is portable to multiple operating systems and Web servers;you aren't locked into deploying on Windows and IIS.Although the core.NET platform runs on a few non-Windows platforms, the ASp part does not.You cannot expect to deploy serious ASp.NET applications on multiple servers and operating systems.For some applications, this difference does not matter.For others, it matters greatly.Second, for some applications the choice of the underlying language matters greatly.For example, although.NET's C# language is very well designed and is similar to Java, fewer programmers are familiar with either the core C# syntax or the many auxiliary libraries.In addition, many developers still use the original version of ASp.With this version, JSp has a clear advantage for the dynamic code.With JSp, the dynamic part is written in Java, not VBScript or another ASp-specific language, so JSp is more powerful and better suited to complex applications that require reusable components.You could make the same argument when comparing JSp to the previous version of ColdFusion;with JSp you can use Java for the “real code” and are not tied to a particular server product.However, the current release of ColdFusion is within the context of a J2EE server, allowing developers to easily mix ColdFusion and servlet/JSp code.Versus pHp

pHp(a recursive acronym for “pHp: Hypertext preprocessor”)is a free, open-source, HTML-embedded scripting language that is somewhat similar to both ASp and JSp.One advantage of JSp is that the dynamic part is written in Java, which already has an extensive ApI for networking, database access, distributed objects, and the like, whereas pHp requires learning an entirely new, less widely used language.A second advantage is that JSp is much more widely supported by tool and server vendors than is pHp.Versus pure Servlets

JSp doesn't provide any capabilities that couldn't, in principle, be accomplished with servlets.In fact, JSp documents are automatically translated into servlets behind the scenes.But it is more convenient to write(and to modify!)regular HTML than to use a zillion println statements to generate the HTML.plus, by separating the presentation from the content, you can put different people on different tasks: your Web page design experts can build the HTML by using familiar tools and either leave places for your servlet programmers to insert the dynamic content or invoke the dynamic content indirectly by means of XML tags.Does this mean that you can just learn JSp and forget about servlets? Absolutely not!JSp developers need to know servlets for four reasons:

1.JSp pages get translated into servlets.You can't understand how JSp works without understanding servlets.2.JSp consists of static HTML, special-purpose JSp tags, and Java code.What kind of Java code? Servlet code!You can't write that code if you don't understand servlet programming.3.Some tasks are better accomplished by servlets than by JSp.JSp is good at generating pages that consist of large sections of fairly well structured HTML or other character data.Servlets are better for generating binary data, building pages with highly variable structure, and performing tasks(such as redirection)that involve little or no output.4.Some tasks are better accomplished by a combination of servlets and JSp than by either servlets or JSp alone.Versus JavaScript

JavaScript, which is completely distinct from the Java programming language, is normally used to dynamically generate HTML on the client, building parts of the Web page as the browser loads the document.This is a useful capability and does not normally overlap with the capabilities of JSp(which runs only on the server).JSp pages still include SCRIpT tags for JavaScript, just as normal HTML pages do.In fact, JSp can even be used to dynamically generate the JavaScript that will be sent to the client.So, JavaScript is not a competing technology;it is a complementary one.It is also possible to use JavaScript on the server, most notably on Sun ONE(formerly iplanet), IIS, and BroadVision servers.However, Java is more powerful, flexible, reliable, and portable.Versus WebMacro or Velocity

JSp is by no means perfect.Many people have pointed out features that could be improved.This is a good thing, and one of the advantages of JSp is that the specification is controlled by a community that draws from many different companies.So, the technology can incorporate improvements in successive releases.However, some groups have developed alternative Java-based technologies to try to address these deficiencies.This, in our judgment, is a mistake.Using a third-party tool like Apache Struts that augments JSp and servlet technology is a good idea when that tool adds sufficient benefit to compensate for the additional complexity.But using a nonstandard tool that tries to replace JSp is a bad idea.When choosing a technology, you need to weigh many factors: standardization, portability, integration, industry support, and technical features.The arguments for JSp alternatives have focused almost exclusively on the technical features part.But portability, standardization, and integration are also very important.For example, the servlet and JSp specifications define a standard directory structure for Web applications and provide standard files(.war files)for deploying Web applications.All JSp-compatible servers must support these standards.Filters can be set up to apply to any number of servlets or JSp pages, but not to nonstandard resources.The same goes for Web application security settings.Besides, the tremendous industry support for JSp and servlet technology results in improvements that mitigate many of the criticisms of JSp.For example, the JSp Standard Tag Library and the JSp 2.0 expression language address two of the most well-founded criticisms: the lack of good iteration constructs and the difficulty of accessing dynamic results without using either explicit Java code or verbose jsp:useBean elements.10.4 Misconceptions About JSp

Forgetting JSp Is Server-Side Technology

Here are some typical questions Marty has received(most of them repeatedly).?Our server is running JDK 1.4.So, how do I put a Swing component in a JSp page?

?How do I put an image into a JSp page? I do not know the proper Java I/O commands to read image files.?Since Tomcat does not support JavaScript, how do I make images that are highlighted when the user moves the mouse over them?

?Our clients use older browsers that do not understand JSp.What should we do?

?When our clients use “View Source” in a browser, how can I prevent them from seeing the JSp tags?

All of these questions are based upon the assumption that browsers know something about the server-side process.But they do not.Thus:

?For putting applets with Swing components into Web pages, what matters is the browser's Java version—the server's version is irrelevant.If the browser supports the Java 2 platform, you use the normal AppLET(or Java plug-in)tag and would do so even if you were using non-Java technology on the server.?You do not need Java I/O to read image files;you just put the image in the directory for Web resources(i.e., two levels up from WEB-INF/classes)and output a normal IMG tag.?You create images that change under the mouse by using client-side JavaScript, referenced with the SCRIpT tag;this does not change just because the server is using JSp.?Browsers do not “support” JSp at all—they merely see the output of the JSp page.So, make sure your JSp outputs HTML compatible with the browser, just as you would do with static HTML pages.?And, of course you need not do anything to prevent clients from seeing JSp tags;those tags are processed on the server and are not part of the output that is sent to the client.Confusing Translation Time with Request Time

A JSp page is converted into a servlet.The servlet is compiled, loaded into the server's memory, initialized, and executed.But which step happens when? To answer that question, remember two points:

?The JSp page is translated into a servlet and compiled only the first time it is accessed after having been modified.?Loading into memory, initialization, and execution follow the normal rules for servlets.Table 1 gives some common scenarios and tells whether or not each step occurs in that scenario.The most frequently misunderstood entries are highlighted.When referring to the table, note that servlets resulting from JSp pages use the _jspService method(called for both GET and pOST requests), not doGet or dopost.Also, for initialization, they use the jspInit method, not the init method.Table 1.JSp Operations in Various Scenarios

JSp page translated into servletServlet compiledServlet loaded into server's memoryjspInit called_jspService called

page first written

Request 1YesYesYesYesYes

Request 2NoNoNoNoYes

Server restarted

Request 3NoNoYesYesYes

Request 4NoNoNoNoYes

page modified

Request 5YesYesYesYesYes

Request 6NoNoNoNoYes

中文翻譯

JSp技術(shù)概述

一、JSp的好處

JSp頁面最終會轉(zhuǎn)換成servler。因而，從根本上，JSp頁面能夠執(zhí)行的任何任務(wù)都可以用servler來完成。然而，這種底層的等同性并不意味著servler和JSp頁面對于所有的情況都等同適用。問題不在于技術(shù)的能力，而是二者在便利性、生產(chǎn)率和可維護(hù)性上的不同。畢竟，在特定平臺上能夠用Java編程語言完成的事情，同樣可以用匯編語言來完成，但是選擇哪種語言依舊十分重要。

和單獨使用servler相比，JSp提供下述好處：

?JSp中HTML的編寫與維護(hù)更為簡單。JSp中可以使用常規(guī)的HTML：沒有額外的反斜杠，沒有額外的雙引號，也沒有暗含的Java語法。

?能夠使用標(biāo)準(zhǔn)的網(wǎng)站開發(fā)工具。即使對那些對JSp一無所知的HTML工具，我們也可以使用，因為它們會忽略JSp標(biāo)簽（JSp tags）。

?可以對開發(fā)團(tuán)隊進(jìn)行劃分。Java程序員可以致力于動態(tài)代碼。Web開發(fā)人員可以將經(jīng)理集中在表示層（presentation layer）上。對于大型的項目，這種劃分極為重要。依據(jù)開發(fā)團(tuán)隊的大小，及項目的復(fù)雜程度，可以對靜態(tài)HTML和動態(tài)內(nèi)容進(jìn)行弱分離（weaker separation）和強(qiáng)分離（stronger separation）。

在此，這個討論并不是讓您停止使用servlets，只使用JSp。幾乎所有的項目都會同時用到這兩種技術(shù)。針對項目中的某些請求，您可能會在MVC構(gòu)架下組合使用這兩項技術(shù)。我們總是希望用適當(dāng)?shù)墓ぞ咄瓿上鄬?yīng)的工作，僅僅是servlet并不能填滿您的工具箱。

二、JSp相對于競爭技術(shù)的優(yōu)勢

許多年前，Marty受到邀請,參加一個有關(guān)軟件技術(shù)的小型(20個人)研討會.做在Marty旁邊的人是James Gosling---Java編程語言的發(fā)明者。隔幾個位置,是來自華盛頓一家大型軟件公司的高級經(jīng)理。在討論過程中,研討會的主席提出了Jini的議題,這在當(dāng)時是一項新的Java技術(shù).主席向該經(jīng)理詢問他的想法.他繼續(xù)說,他們會持續(xù)關(guān)注這項技術(shù),如果這項技術(shù)變得流行起來,他們會遵循公司的“接受并擴(kuò)充(embrace and extend)”的策略.此時, Gosling隨意地插話說“你的意思其實就是不接受且不擴(kuò)充(disgrace and distend)?！?/p>

在此, Gosling的抱怨顯示出，他感到這個公司會從其他公司那里拿走技術(shù),用于他們自己的目的.但你猜這次怎么樣?這次鞋子穿在了另一只腳上。Java社團(tuán)沒有發(fā)明這一思想----將頁面設(shè)計成由靜態(tài)HTML和用特殊標(biāo)簽標(biāo)記的動態(tài)代碼混合組成.。ColdFusion多年前就已經(jīng)這樣做了。甚至ASp(來自于前述經(jīng)理所在公司的一項產(chǎn)品)都在JSp出現(xiàn)之前推廣了這種方式。實際上,JSp不只采用了這種通用概念,它甚至使用許多和ASp相同的特殊標(biāo)簽。

因此,問題變成:為什么使用JSp,而不使用其他技術(shù)呢?我們的第一反應(yīng)是我們不是在爭論所有的人應(yīng)該做什么。其他這些技術(shù)中,有一些也很不錯,在某些情況下也的確是合情合理的選擇.然而,在其他情形中,JSp明顯要更好一些。下面給出幾個理由。

與.NET和Active Server pages(ASp)相比

.NET是Microsoft精心設(shè)計的一項技術(shù)。ASp.NET是與servlets和JSp直接競爭的技術(shù)。JSp的優(yōu)勢體現(xiàn)在兩個方面。

首先,JSp可以移植到多種操作系統(tǒng)和Web服務(wù)器,您不必僅僅局限于部署在Windows 和IIS上盡管核心.NET平臺可以在好幾種非Windows平臺上運(yùn)行，但ASp這一部分不可以。您不能期望可以將重要的ASp.NET應(yīng)用部署到多種服務(wù)器和操作系統(tǒng)。對于某些應(yīng)用，這種差異沒有什么影響。但有些應(yīng)用，這種差異卻非常重要。

其次，對于某些應(yīng)用，底層語言的選擇至關(guān)重要。例如，盡管.NET的C#語言設(shè)計優(yōu)良，且和Java類似，但熟悉核心C#語法和眾多工具庫的程序員很少。此外,許多開發(fā)者依舊使用最初版本的ASp。相對于這個版本,JSp在動態(tài)代碼方面擁有明顯的優(yōu)勢。使用JSp,動態(tài)部分是用Java編寫的,而非VBScript過其他ASp專有的語言,因此JSp更為強(qiáng)勁,更適合于要求組件重用的復(fù)雜應(yīng)用。

當(dāng)將JSp與之前版本的ColdFusion對比時，您可能會得到相同的結(jié)論。應(yīng)用JSp，您可以使用Java編寫“真正的代碼”，不必依賴于特定的服務(wù)器產(chǎn)品。然而，當(dāng)前版本的ColdFusion滿足J2EE服務(wù)器的環(huán)境，允許開發(fā)者容易的混合使用ColdFusion和Servlet/JSp代碼。

與pHp相比

pHp（“pHp：Hypertext preprocessor”的遞歸字母縮寫詞）是免費(fèi)的、開放源代碼的、HTML嵌入其中的腳本語言，與ASp和JSp都有某種程度的類似。JSp的一項優(yōu)勢是動態(tài)部分用Java編寫，而Java已經(jīng)在聯(lián)網(wǎng)、數(shù)據(jù)庫訪問、分布式對象等方面擁有廣泛的ApI，而pHp需要學(xué)習(xí)全新的、應(yīng)用相對廣泛的語言。JSp的第二項優(yōu)勢是，和pHp相比，JSp擁有極為廣泛的工具和服務(wù)器提供商的支持。

與純Servlet相比

原則上，JSp并沒有提供Servlet不能完成的功能。實際上，JSp文檔在后臺被自動轉(zhuǎn)換成Servlet。但是編寫（和修改）常規(guī)的HTML，要比無數(shù)println語句生成HTML要方便得多。另外，通過將表示與內(nèi)容分離，可以為不同的人分配不同的任務(wù)：網(wǎng)頁設(shè)計人員使用熟悉的工具構(gòu)建HTML，要么為Servlet程序員留出空間插入動態(tài)內(nèi)容，要么通過XML標(biāo)簽間接調(diào)用動態(tài)內(nèi)容。

這是否表示您只可以學(xué)習(xí)JSp，將Servlet丟到一邊呢？當(dāng)然不是！由于以下4種原因，JSp開發(fā)人員需要了解Servlet：

（1）JSp頁面會轉(zhuǎn)換成Servlet。不了解Servlet就無法知道JSp如何工作。

（2）JSp由靜態(tài)HTML、專用的JSp標(biāo)簽和Java代碼組成。哪種類型的Java代碼呢？當(dāng)然是Servlet代碼！如果不了解Servlet編程，那么就無法編寫這種代碼。

（3）一些任務(wù)用Servlet完成比用JSp來完成要好。JSp擅長生成由大量組織有序的結(jié)構(gòu)化HTML或其他字符數(shù)據(jù)組成的頁面。Servlet擅長生成二進(jìn)制數(shù)據(jù)，構(gòu)建結(jié)構(gòu)多樣的頁面，以及執(zhí)行輸出很少或者沒有輸出的任務(wù)（比如重定向）。

（4）有些任務(wù)更適合于組合使用Servlet和JSp來完成，而非單獨使用Servlet或JSp。

與JavaScript相比

JavaScript和Java編程語言完全是兩碼事，前者一般用于在客戶端動態(tài)生成HTML，在瀏覽器載入文檔時構(gòu)建網(wǎng)頁的部分內(nèi)容。這是一項有用的功能，一般與JSp的功能（只在服務(wù)器端運(yùn)行）并不發(fā)生重疊。和常規(guī)HTML頁面一樣，JSp頁面依舊可以包括用于JavaScript的SCRIpT標(biāo)簽。實際上，JSp甚至能夠用來動態(tài)生成發(fā)送到客戶端的JavaScript。因此，JavaScript不是一項競爭技術(shù)，它是一項補(bǔ)充技術(shù)。

JavaScript也可以用在服務(wù)器端，最因人注意的是SUN ONE（以前的iplanet）、IIS和BroadVision服務(wù)器。然而，Java更為強(qiáng)大靈活、可靠且可移植。

與WebMacro和Velocity相比

JSp決非完美。許多人都曾指出過JSp中能夠改進(jìn)的功能。這是一件好事，JSp的優(yōu)勢之一是該規(guī)范由許多不同公司組成的社團(tuán)控制。因此，在后續(xù)版本中，這項技術(shù)能夠得到協(xié)調(diào)的改進(jìn)。

但是，一些組織已經(jīng)開發(fā)出了基于Java的替代技術(shù)，試圖彌補(bǔ)這些不足。據(jù)我們的判斷，這樣做是錯誤的。使用擴(kuò)充JSp和Servlet技術(shù)的第三方工具，如Apache Structs，是一種很好的思路，只要該工具帶來的好處能夠補(bǔ)償工具帶來的額外復(fù)雜性。但是，試圖使用非標(biāo)準(zhǔn)的工具代替JSp則不理想。在選擇一項技術(shù)時，需要權(quán)衡許多方面的因素：標(biāo)準(zhǔn)化、可移植性、集成性、行業(yè)支持和技術(shù)特性。對于JSp替代技術(shù)的爭論幾乎只是集中在技術(shù)特性上，而可移植性、標(biāo)準(zhǔn)化和集成性也十分重要。例如，Servlet和JSp規(guī)范為Web應(yīng)用定義了一個標(biāo)準(zhǔn)的目錄結(jié)構(gòu)，并提供用于部署Web應(yīng)用的標(biāo)準(zhǔn)文件（.war文件）。所有JSp兼容的服務(wù)器必須支持這些標(biāo)準(zhǔn)。我們可以建立過濾器作用到任意樹木的Servlet和JSp頁面上，但不能用于非標(biāo)準(zhǔn)資源。Web應(yīng)用安全設(shè)置也同樣如此。

此外，業(yè)界對JSp和Servlet技術(shù)的巨大支持使得這兩項技術(shù)都有了巨大的進(jìn)步，從而減輕了對JSp的許多批評。例如，JSp標(biāo)準(zhǔn)標(biāo)簽庫和JSp 2.0表達(dá)式語言解決了兩種最廣泛的批評：缺乏良好的迭代結(jié)構(gòu)；不使用顯式的Java代碼或冗長的jsp:useBean元素難以訪問動態(tài)結(jié)果。

三、對JSp的誤解

忘記JSp技術(shù)是服務(wù)器端技術(shù)

下面是Marty收到的一些典型問題（大部分問題不止一次的出現(xiàn)）。

?我們的服務(wù)器正在運(yùn)行JDK1.4。我如何將Swing組件用到JSp頁面中呢？

?我如何將圖像放到JSp頁面中？我不知道讀取圖像文件應(yīng)該使用哪些Java I/O命令。

?Tomcat不支持JavaScript，當(dāng)用戶在圖像上移動鼠標(biāo)時，我如何使圖像突出顯示呢？

?我們的客戶使用不理解JSp的舊瀏覽器。我應(yīng)該怎么做？

?當(dāng)我們的客戶在瀏覽器中使用“View Source”（查看源代碼）時，如何阻止他們看到JSp標(biāo)簽？

所有這些問題都基于瀏覽器對服務(wù)器端的過程在有所了解的假定之上。但事實上瀏覽器并不了解服務(wù)器端的過程。因此：

?如果要將使用Swing組件的applet放到網(wǎng)頁中，重要的是瀏覽器的Java版本，和服務(wù)器的Java版本無關(guān)。如果瀏覽器支持Java 2平臺，您可以使用正常的AppLET（或Java插件）標(biāo)簽，即使在服務(wù)器上使用了非Java技術(shù)也須如此。

?您不需要Java I/O來讀取圖像文件，您只需將圖像放在存儲Web資源的目錄中（即WEB-INF/classes向上兩級的目錄），并輸出一個正常的IMG標(biāo)簽。

?您應(yīng)該用SCRIpT標(biāo)簽，使用客戶端JavaScript創(chuàng)建在鼠標(biāo)下會更改的圖像，這不會由于服務(wù)器使用JSp而改變。

?瀏覽器根本不“支持”JSp----它們看到的只是JSp頁面的輸出。因此，如同對待靜態(tài)HTML頁面一樣，只需確保JSp輸出的HTML與瀏覽器兼容。

?當(dāng)然，您不需要采取什么措施來阻止客戶看到JSp標(biāo)簽，這些標(biāo)簽在服務(wù)器上進(jìn)行處理，發(fā)送給客戶的輸出中并不出現(xiàn)。

混淆轉(zhuǎn)換期間和請求期間

JSp頁面需要轉(zhuǎn)換成servlet。Servlet在編譯后，載入到服務(wù)器的內(nèi)容中，初始化并執(zhí)行。但是每一步發(fā)生在什么時候呢？要回答這個問題，要記住以下兩點：

?JSp頁面僅在修改后第一次被訪問時，才會被轉(zhuǎn)換成servlet并進(jìn)行編譯；

?載入到內(nèi)存中、初始化和執(zhí)行遵循servlet的一般規(guī)則。

表1列出一些常見的情形，講述在該種情況下每一步是否發(fā)生。最常被誤解的項已經(jīng)突出標(biāo)示出來。在參考該表時，要注意，由JSp頁面生成的servlet使用_jspService方法（GET和pOST請求都調(diào)用該函數(shù)），不是doGet或dopost方法。同樣，對于初始化，它們使用jspInit方法，而非init方法。

表1 各種情況下的JSp操作

將JSp 頁面轉(zhuǎn)換成servlet編譯Servlet 將Servlet 載入到服務(wù)器內(nèi)存中調(diào)用jspInit 調(diào)用_jspService

頁面初次創(chuàng)建

請求 1有有有有有

請求 2無無無無有

服務(wù)器重啟后

請求3無無有有有

請求 4無無無無有

頁面修改后

請求 5有有有有有

請求 6無無無無有

第五篇：4畢業(yè)設(shè)計(論文)外文文獻(xiàn)翻譯范文

黃石理工學(xué)院畢業(yè)設(shè)計（論文）外文文獻(xiàn)翻譯

模糊控制理論

摘自 維基百科 2011年11月20日

概述

模糊邏輯廣泛適用于機(jī)械控制。這個詞本身激發(fā)一個一定的懷疑,試探相當(dāng)于“倉促的邏輯”或“虛假的邏輯”,但“模糊”不是指一個部分缺乏嚴(yán)格性的方法,而這樣的事實,即邏輯涉及能處理的概念,不能被表達(dá)為“對”或“否”,而是因為“部分真實”。雖然遺傳算法和神經(jīng)網(wǎng)絡(luò)可以執(zhí)行一樣模糊邏輯在很多情況下,模糊邏輯的優(yōu)點是解決這個問題的方法,能夠被鑄造方面接線員能了解,以便他們的經(jīng)驗,可用于設(shè)計的控制器。這讓它更容易完成機(jī)械化已成功由人執(zhí)行。

歷史以及應(yīng)用

模糊邏輯首先被提出是有Lotfi在加州大學(xué)伯克利分校在1965年的一篇論文。他闡述了他的觀點在1973年的一篇論文的概念,介紹了語言變量”,在這篇文章中相當(dāng)于一個變量定義為一個模糊集合。其他研究打亂了,第二次工業(yè)應(yīng)用中,水泥窯建在丹麥,即將到來的在線1975。

模糊系統(tǒng)在很大程度上在美國被忽略了,因為他們更多關(guān)注的是人工智能，一個被過分吹噓的領(lǐng)域，尤其是在1980年中期年代,導(dǎo)致在誠信缺失的商業(yè)領(lǐng)域。

然而日本人對這個卻沒有偏見和忽略，模糊系統(tǒng)引發(fā)日立的Seiji Yasunobu和Soji Yasunobu Miyamoto的興趣。,他于1985年的模擬,證明了模糊控制系統(tǒng)對仙臺鐵路的控制的優(yōu)越性。他們的想法是被接受了,并將模糊系統(tǒng)用來控制加速、制動、和停車，當(dāng)線于1987年開業(yè)。

1987年另一項促進(jìn)模糊系統(tǒng)的興趣。在一個國際會議在東京的模糊研究那一年,Yamakawa論證<使用模糊控制,通過一系列簡單的專用模糊邏輯芯片,在一個“倒立擺“實驗。這是一個經(jīng)典的控制問題,在這一過程中,車輛努力保持桿安裝在頂部用鉸鏈正直來回移動。

這次展示給觀察者家們留下了深刻的印象,以及后來的實驗,他登上一Yamakawa酒杯包含水或甚至一只活老鼠的頂部的鐘擺。該系統(tǒng)在兩種情況下,保持穩(wěn)定。Yamakawa最終繼續(xù)組織自己的fuzzy-systems研究實驗室?guī)椭米约旱膶＠谔锏乩锏臅r候。

黃石理工學(xué)院畢業(yè)設(shè)計（論文）外文文獻(xiàn)翻譯

展示之后,日本工程師開發(fā)出了大范圍的模糊系統(tǒng)用于工業(yè)領(lǐng)域和消費(fèi)領(lǐng)域的應(yīng)用。1988年,日本建立了國際模糊工程實驗室,建立合作安排48公司進(jìn)行模糊控制的研究。

松下吸塵器使用微控制器運(yùn)行模糊算法去控制傳感器和調(diào)整吸塵力。日立洗衣機(jī)用模糊控制器Load-Weight,Fabric-Mix和塵土傳感器及自動設(shè)定洗滌周期來最佳利用電能、水和洗滌劑。

佳能研制出的一種上相機(jī)使用電荷耦合器件(CCD)測量中的圖像清晰的六個區(qū)域其視野和使用提供的信息來決定是否這個影像在焦點上(清晰)。它也可以追蹤變化的速率在鏡頭運(yùn)動的重點,以及它的速度以防止控制超調(diào)。相機(jī)的模糊控制系統(tǒng)采用12輸入,6個輸入了解解現(xiàn)行清晰所提供的數(shù)據(jù)和其他6個輸入測量CCD鏡頭的變化率的運(yùn)動。輸出的位置是鏡頭。模糊控制系統(tǒng)應(yīng)用13條規(guī)則,需要1.1 千字節(jié)記憶信息。

另外一個例子是,三菱工業(yè)空調(diào)設(shè)計采用25加熱規(guī)則和25冷卻規(guī)則。溫度傳感器提供輸入,輸出一個控制逆變器,一個壓縮機(jī)氣閥,風(fēng)扇電機(jī)。和以前的設(shè)計相比,新設(shè)計的模糊控制器增加五次加熱冷卻速度,降低能耗24%,增加溫度穩(wěn)定性的一個因素兩個,使用較少的傳感器。

日本人對模糊邏輯的人情是反映在很廣泛的應(yīng)用范圍上,他們一直在研究或?qū)崿F(xiàn):例如個性和筆跡識別光學(xué)模糊系統(tǒng),機(jī)器人,聲控機(jī)器人直升飛機(jī)。

模糊系統(tǒng)的相關(guān)研究工作也在美國和歐洲進(jìn)行著。美國環(huán)境保護(hù)署分析了模糊控制節(jié)能電動機(jī),美國國家航空和宇宙航行局研究了模糊控制自動太空對接。仿真結(jié)果表明,模糊控制系統(tǒng)可大大降低燃料消耗。如波音公司、通用汽車、艾倫-布拉德利、克萊斯勒、伊頓,和漩渦了模糊邏輯用于低功率冰箱、改善汽車變速箱。在1995年美泰克公司推出的一個“聰明” 基于模糊控制器洗碗機(jī)，“一站式感應(yīng)模塊”包括熱敏電阻器,用來溫度測量;電導(dǎo)率傳感器,用來測量離子洗滌劑水平存在于洗;分散和濁度傳感器用來檢測透射光測量失禁的洗滌,以及一個磁致伸縮傳感器來讀取旋轉(zhuǎn)速率。這個系統(tǒng)確定最優(yōu)洗周期任何載荷,獲得最佳的結(jié)果用最少的能源、洗滌劑、和水。

研究和開發(fā)還繼續(xù)模糊應(yīng)用軟件,作為反對固件設(shè)計,包括模糊專家系統(tǒng)模糊邏輯與整合神經(jīng)網(wǎng)絡(luò)和所謂的自適應(yīng)遺傳軟件系統(tǒng),其最終目的是建立“自主學(xué)習(xí)”模糊控制系統(tǒng)。

黃石理工學(xué)院畢業(yè)設(shè)計（論文）外文文獻(xiàn)翻譯

模糊集

輸入變量在一個模糊控制系統(tǒng)是集映射到一般由類似的隸屬度函數(shù),稱為“模糊集”。轉(zhuǎn)換的過程中,一個干脆利落的輸入值模糊值稱為“模糊化”。

一個控制系統(tǒng)也有各種不同的類型開關(guān)或“開關(guān)”,連同它的模擬輸入輸入,而這樣的開關(guān)輸入當(dāng)然總有一個真實的價值等于要么1或0,但該方案能對付他們,簡單的模糊函數(shù),要么發(fā)生一個值或另一個。

賦予了“映射輸入變量的隸屬函數(shù)和進(jìn)入真理價值,單片機(jī)然后做出決定為采取何種行動基于一套“規(guī)則”,每一組的形式。

在一個例子里,有兩個輸入變量是“剎車溫度”和“速度”,定義為模糊集值。輸出變量,“制動壓力” ,也定義為一個模糊集,有價值觀像“靜”、“稍微增大” “略微下降”,等等。

這條規(guī)則本身很莫名其妙,因為它看起來好像可以使用，會干擾到與模糊,但要記住,這個決定是基于一套規(guī)則。

所有的規(guī)則都調(diào)用申請,使用模糊隸屬度函數(shù)和誠實得到輸入值,確定結(jié)果的規(guī)則。這個結(jié)果將被映射成一個隸屬函數(shù)和控制輸出變量的真值。

這些結(jié)果相結(jié)合,給出了具體的(“脆”)的答案,實際的制動壓力,一個過程被稱為解模糊化，結(jié)合了模糊操作規(guī)則 “推理“描述”模糊專家系統(tǒng)”。

傳統(tǒng)的控制系統(tǒng)是基于數(shù)學(xué)模型的控制系統(tǒng),描述了使用一個或更多微分方程確定系統(tǒng)回應(yīng)其輸入。這類系統(tǒng)通常被作為“PID控制器”他們是產(chǎn)品的數(shù)十年的發(fā)展建設(shè)和理論分析,是非常有效的。

如果PID和其他傳統(tǒng)的控制系統(tǒng)是如此的先進(jìn),何必還要模糊控制嗎?它有一些優(yōu)點。在許多情況下,數(shù)學(xué)模型的控制過程可能不存在,或太“貴”的認(rèn)識論的計算機(jī)處理能力和內(nèi)存,與系統(tǒng)的基于經(jīng)驗規(guī)則可能更有效。

此外,模糊邏輯都適合低成本實現(xiàn)基于廉價的傳感器、低分辨率模擬/數(shù)字轉(zhuǎn)換器,或8位單片機(jī)芯片one-chip 4比特。這種系統(tǒng)可以很容易地通過增加新的規(guī)則升級來提高性能或添加新功能。在許多情況下,模糊控制可以用來改善現(xiàn)有的傳統(tǒng)控制器系統(tǒng)通過增加了額外的情報電流控制方法。

模糊控的細(xì)節(jié)

模糊控制器是很簡單的理念上。它們是由一個輸入階段,一個處理階段,一個輸

黃石理工學(xué)院畢業(yè)設(shè)計（論文）外文文獻(xiàn)翻譯

出階段。地圖傳感器輸入級或其他輸入,比如開關(guān)等等,到合適的隸屬函數(shù)和真理的價值。每一個適當(dāng)?shù)募庸るA段調(diào)用規(guī)則和產(chǎn)生的結(jié)果對每個人來說,然后結(jié)合結(jié)果的規(guī)則。最后,將結(jié)果輸出階段相結(jié)合的具體控制輸出回他的價值。

最常見的形狀是三角形的隸屬度函數(shù),盡管梯形和貝爾曲線也使用,但其形狀通常比數(shù)量更重要曲線及其位置。從三人至七人通常是適當(dāng)?shù)母采w曲線所需要的范圍的一個輸入值,或“宇宙的話語“在模糊術(shù)語。

作為討論之前,加工階段是基于規(guī)則的集合的形式邏輯IFThen規(guī)則。作為一個例子,解釋一個規(guī)則,因為如果(溫度是“冷”),那么(加熱器是“高”)由第一階表達(dá)式冷(x)→高(y)和假設(shè)r是一個輸入這樣冷(r)是假的。然后公式冷(r)→高(t)是適用于任何一個師,因此任何不正確的控制提供了一種給r。很明顯,如果我們考慮系統(tǒng)的先例的規(guī)則類定義一個分區(qū)這樣一個自相矛盾的現(xiàn)象不會出現(xiàn)。在任何情況下它有時是不考慮兩個變量x和y在一條規(guī)則沒有某種功能的依賴。嚴(yán)謹(jǐn)?shù)倪壿嬚?dāng)化中給出的模糊控制Hajek的書,被描繪成一個模糊控制理論的基本Hajek邏輯。在2005 Gerla模糊控制邏輯方法,提出了一種基于以下的想法。f模糊函數(shù)表示的系統(tǒng)與模糊控制相結(jié)合,即:給定輸入r,s(y)?f(r,y)是模糊集合可能的輸出。然后給出一個可能的輸出的t,我們把f(r,t)為真理程度的表示。更多的是任何系統(tǒng)的If-Then規(guī)則可轉(zhuǎn)化為一個模糊的程序,在這種情況下模糊函數(shù)f模糊謂詞的解釋很好(x,y)在相關(guān)的最小模糊Herbrand

模型。以這樣一種方式成為一個章模糊控制的模糊邏輯編程。學(xué)習(xí)過程成為一個問題屬于歸納邏輯理論。

黃石理工學(xué)院畢業(yè)設(shè)計（論文）外文文獻(xiàn)翻譯

Fuzzy Control From Wikipedia November 2011

Overview

Fuzzy logic is widely used in machine control.The term itself inspires a certain skepticism, sounding equivalent to ”half-baked logic“ or ”bogus logic“, but the ”fuzzy“ part does not refer to a lack of rigour in the method, rather to the fact that the logic involved can deal with concepts that cannot be expressed as ”true“ or ”false“ but rather as ”partially true“.Although genetic algorithms and neural networks can perform just as well as fuzzy logic in many cases, fuzzy logic has the advantage that the solution to the problem can be cast in terms that human operators can understand, so that their experience can be used in the design of the controller.This makes it easier to mechanize tasks that are already successfully performed by humans.History and applications

Fuzzy logic was first proposed by Lotfi A.Zadeh of the University of California at Berkeley in a 1965 paper.He elaborated on his ideas in a 1973 paper that introduced the concept of ”linguistic variables“, which in this article equates to a variable defined as a fuzzy set.Other research followed, with the first industrial application, a cement kiln built in Denmark, coming on line in 1975.Fuzzy systems were largely ignored in the U.S.because they were associated with artificial intelligence, a field that periodically oversells itself, especially in the mid-1980s, resulting in a lack of credibility within the commercial domain.The Japanese did not have this prejudice.Interest in fuzzy systems was sparked by Seiji Yasunobu and Soji Miyamoto of Hitachi, who in 1985 provided simulations that demonstrated the superiority of fuzzy control systems for the Sendai railway.Their ideas were adopted, and fuzzy systems were used to control accelerating, braking, and stopping when the line opened in 1987.Another event in 1987 helped promote interest in fuzzy systems.During an international meeting of fuzzy researchers in Tokyo that year, Takeshi Yamakawa demonstrated the use of fuzzy control, through a set of simple dedicated fuzzy logic chips, in an ”inverted pendulum“ experiment.This is a classic control problem, in which a vehicle tries to keep a pole mounted on its top by a hinge upright by moving back and forth.Observers were impressed with this demonstration, as well as later experiments by Yamakawa in which he mounted a wine glass containing water or even a live mouse to the top of the pendulum.The system maintained stability in both cases.Yamakawa eventually went on to organize his own fuzzy-systems research lab to help exploit his patents in the field.Following such demonstrations, Japanese engineers developed a wide range of fuzzy systems for both industrial and consumer applications.In 1988 Japan established

黃石理工學(xué)院畢業(yè)設(shè)計（論文）外文文獻(xiàn)翻譯

the Laboratory for International Fuzzy Engineering(LIFE), a cooperative arrangement between 48 companies to pursue fuzzy research.Matsushita vacuum cleaners use micro controllers running fuzzy algorithms to interrogate dust sensors and adjust suction power accordingly.Hitachi washing machines use fuzzy controllers to load-weight, fabric-mix, and dirt sensors and automatically set the wash cycle for the best use of power, water, and detergent.Canon developed an autofocusing camera that uses a charge-coupled device(CCD)to measure the clarity of the image in six regions of its field of view and use the information provided to determine if the image is in focus.It also tracks the rate of change of lens movement during focusing, and controls its speed to prevent overshoot.The camera's fuzzy control system uses 12 inputs: 6 to obtain the current clarity data provided by the CCD and 6 to measure the rate of change of lens movement.The output is the position of the lens.The fuzzy control system uses 13 rules and requires 1.1 kilobytes of memory.As another example of a practical system, an industrial air conditioner designed by Mitsubishi uses 25 heating rules and 25 cooling rules.A temperature sensor provides input, with control outputs fed to an inverter, a compressor valve, and a fan motor.Compared to the previous design, the fuzzy controller heats and cools five times faster, reduces power consumption by 24%, increases temperature stability by a factor of two, and uses fewer sensors.The enthusiasm of the Japanese for fuzzy logic is reflected in the wide range of other applications they have investigated or implemented: character and handwriting recognition;optical fuzzy systems;robots, voice-controlled robot helicopters Work on fuzzy systems is also proceeding in the US and Europe.The US Environmental Protection Agency has investigated fuzzy control for energy-efficient motors, and NASA has studied fuzzy control for automated space docking: simulations show that a fuzzy control system can greatly reduce fuel consumption.Firms such as Boeing, General Motors, Allen-Bradley, Chrysler, Eaton, and Whirlpool have worked on fuzzy logic for use in low-power refrigerators, improved automotive transmissions, and energy-efficient electric motors.In 1995 Maytag introduced an ”intelligent“ dishwasher based on a fuzzy controller and a ”one-stop sensing module“ that combines a thermistor, for temperature measurement;a conductivity sensor, to measure detergent level from the ions present in the wash;a turbidity sensor that measures scattered and transmitted light to measure the soiling of the wash;and a magnetostrictive sensor to read spin rate.The system determines the optimum wash cycle for any load to obtain the best results with the least amount of energy, detergent, and water.Research and development is also continuing on fuzzy applications in software, as opposed to firmware, design, including fuzzy expert systems and integration of fuzzy logic with neural-network and so-called adaptive ”genetic“ software systems, with the ultimate goal of building ”self-learning“ fuzzy control systems.黃石理工學(xué)院畢業(yè)設(shè)計（論文）外文文獻(xiàn)翻譯

Fuzzy sets

The input variables in a fuzzy control system are in general mapped into by sets of membership functions similar to this, known as ”fuzzy sets“.The process of converting a crisp input value to a fuzzy value is called ”fuzzification“.A control system may also have various types of switch, or ”O(jiān)N-OFF“, inputs along with its analog inputs, and such switch inputs of course will always have a truth value equal to either 1 or 0, but the scheme can deal with them as simplified fuzzy functions that happen to be either one value or another.Given ”mappings“ of input variables into membership functions and truth values, the microcontroller then makes decisions for what action to take based on a set of ”rules“, each of the form.In one example, the two input variables are ”brake temperature“ and ”speed“ that have values defined as fuzzy sets.The output variable, ”brake pressure“, is also defined by a fuzzy set that can have values like ”static“, ”slightly increased“, ”slightly decreased“, and so on.This rule by itself is very puzzling since it looks like it could be used without bothering with fuzzy logic, but remember that the decision is based on a set of rules:

All the rules that apply are invoked, using the membership functions and truth values obtained from the inputs, to determine the result of the rule.This result in turn will be mapped into a membership function and truth value controlling the output variable.These results are combined to give a specific(”crisp“)answer, the actual brake pressure, a procedure known as ”defuzzification“.This combination of fuzzy operations and rule-based ”inference“ describes a ”fuzzy expert system“.Traditional control systems are based on mathematical models in which the control system is described using one or more differential equations that define the system response to its inputs.Such systems are often implemented as ”PID controllers“(proportional-integral-derivative controllers).They are the products of decades of development and theoretical analysis, and are highly effective.If PID and other traditional control systems are so well-developed, why bother with fuzzy control? It has some advantages.In many cases, the mathematical model of the control process may not exist, or may be too ”expensive“ in terms of computer processing power and memory, and a system based on empirical rules may be more effective.Furthermore, fuzzy logic is well suited to low-cost implementations based on cheap sensors, low-resolution analog-to-digital converters, and 4-bit or 8-bit one-chip microcontroller chips.Such systems can be easily upgraded by adding new rules to improve performance or add new features.In many cases, fuzzy control can be used to improve existing traditional controller systems by adding an extra layer of intelligence to the current control method.黃石理工學(xué)院畢業(yè)設(shè)計（論文）外文文獻(xiàn)翻譯

Fuzzy control in detail

Fuzzy controllers are very simple conceptually.They consist of an input stage, a processing stage, and an output stage.The input stage maps sensor or other inputs, such as switches, thumbwheels, and so on, to the appropriate membership functions and truth values.The processing stage invokes each appropriate rule and generates a result for each, then combines the results of the rules.Finally, the output stage converts the combined result back into a specific control output value.The most common shape of membership functions is triangular, although trapezoidal and bell curves are also used, but the shape is generally less important than the number of curves and their placement.From three to seven curves are generally appropriate to cover the required range of an input value, or the ”universe of discourse“ in fuzzy jargon.As discussed earlier, the processing stage is based on a collection of logic rules in the form of IF-THEN statements, where the IF part is called the ”antecedent“ and the THEN part is called the ”consequent“.This rule uses the truth value of the ”temperature“ input, which is some truth value of ”cold“, to generate a result in the fuzzy set for the ”heater“ output, which is some value of ”high“.This result is used with the results of other rules to finally generate the crisp composite output.Obviously, the greater the truth value of ”cold“, the higher the truth value of ”high“, though this does not necessarily mean that the output itself will be set to ”high“ since this is only one rule among many.In some cases, the membership functions can be modified by ”hedges“ that are equivalent to adjectives.Common hedges include ”about“, ”near“, ”close to“, ”approximately“, ”very“, ”slightly“, ”too“, ”extremely“, and ”somewhat“.These operations may have precise definitions, though the definitions can vary considerably between different implementations.”Very“, for one example, squares membership functions;since the membership values are always less than 1, this narrows the membership function.”Extremely“ cubes the values to give greater narrowing, while ”somewhat“ broadens the function by taking the square root.In practice, the fuzzy rule sets usually have several antecedents that are combined using fuzzy operators, such as AND, OR, and NOT, though again the definitions tend to vary: AND, in one popular definition, simply uses the minimum weight of all the antecedents, while OR uses the maximum value.There is also a NOT operator that subtracts a membership function from 1 to give the ”complementary“ function.There are several ways to define the result of a rule, but one of the most common and simplest is the ”max-min“ inference method, in which the output membership function is given the truth value generated by the premise.Rules can be solved in parallel in hardware, or sequentially in software.The results of all the rules that have fired are ”defuzzified“ to a crisp value by one of several methods.There are dozens in theory, each with various advantages and drawbacks.The ”centroid“ method is very popular, in which the ”center of mass“ of the result provides the crisp value.Another approach is the ”height“ method, which takes the value of the biggest contributor.The centroid method favors the rule with the output of

黃石理工學(xué)院畢業(yè)設(shè)計（論文）外文文獻(xiàn)翻譯

greatest area, while the height method obviously favors the rule with the greatest output value.The diagram below demonstrates max-min inferring and centroid defuzzification for a system with input variables ”x“, ”y“, and ”z“ and an output variable ”n“.Note that ”mu“ is standard fuzzy-logic nomenclature for ”truth value“:

Fuzzy control system design is based on empirical methods, basically a methodical approach to trial-and-error.The general process is as follows:

1.Document the system's operational specifications and inputs and outputs.2.Document the fuzzy sets for the inputs.3.Document the rule set.4.Determine the defuzzification method.5.Run through test suite to validate system, adjust details as required.6.Complete document and release to production.Logical interpretation of fuzzy control In spite of the appearance there are several difficulties to give a rigorous logical interpretation of the IF-THEN rules.As an example, interpret a rule as IF(temperature is ”cold“)THEN(heater is ”high“)by the first order formula Cold(x)→High(y)and assume that r is an input such that Cold(r)is false.Then the formula Cold(r)→High(t)is true for any t and therefore any t gives a correct control given r.Obviously, if we consider systems of rules in which the class antecedent define a partition such a paradoxical phenomenon does not arise.In any case it is sometimes unsatisfactory to consider two variables x and y in a rule without some kind of functional dependence.A rigorous logical justification of fuzzy control is given in Hájek's book ,where fuzzy control is represented as a theory of Hájek's basic logic.Also in Gerla 2005 a logical approach to fuzzy control is proposed based on the following idea.Denote by f the fuzzy function associated with the fuzzy control system, i.e., given the input r, s(y)= f(r,y)is the fuzzy set of possible outputs.Then given a possible output 't', we interpret f(r,t)as the truth degree of the claim ”t is a good answer given r".More formally, any system of IF-THEN rules can be translate into a fuzzy program in such a way that the fuzzy function f is the interpretation of a vague predicate Good(x,y)in the associated least fuzzy Herbrand model.In such a way fuzzy control becomes a chapter of fuzzy logic programming.The learning process becomes a question belonging to inductive logic theory.