在线聊天系统中英文对照外文翻译文献.docx

1、在线聊天系统中英文对照外文翻译文献中英文对照外文翻译(文档含英文原文和中文翻译)Modeling and specification of Web services composition using UML-SAbstractAs Web services composition arouses a growing interest, most research works address implementation and execution issues. Therefore, many composition languages (BPEL, XLANG, WSFL, WSCI, t

2、o name a few of them) have been proposed in the past few years. However, a weakness of these languages is that they are difficult to use in early stages of development, such as specification. In this paper, an extension to UML 2.0 called ”UML-S: UML for Services” is introduced. UML-S allows for a Mo

3、del Driven Engineering (MDE) of Web services and their interactions.1. IntroductionMany companies are now using the Web as a platform to communicate with their partners. The Web and its technologies allows them to provide Web services to individuals as well as other businesses.The main challenges in

4、 the Web services paradigm are their discovery and their composition. In other words, one must be able to find a suitable Web service for a given task. This process is called the discovery 18, 19. The second challenge is the one that is addressed in this paper. It is known as Web services compositio

5、n 4, 10. In Web services composition, already defined services are used together to achieve a larger task, resulting in a new composite and value-added Web service. To accomplish this purpose, a common approach is to allow the Web services to interact in a scenario through the use of messaging mecha

6、nisms.Although a lot of research works deal with Web services interactions, most of them address language, implementation or application issues, neglecting early stages of the development process, such as specification. To address this issue, an extension to UML 2.0 called ”UML-S: UML for Services”

7、is introduced. UML-S allows for modeling Web services as well as their interactions.The Unified Modeling Language (UML) has been defined by the Object Management Group (OMG) 2 to express graphically system development models.UML-S enables the developers to build composite Web services by following t

8、he principles of the Model-Driven Architecture (MDA). As a consequence, it is possible to generate platform-specific code from high-level UML-S models.This paper is structured as follows. Section 2 provides a survey of existing approaches to model Web services interactions. In section 3, the require

9、ments for a good Web services composition modeling language are put forward. UML-S is then presented in details in section 4. After that, a case study is provided in section 5 to observe UML-S in action. Finally, section 6 draws the conclusions and presents future work.2. Related WorkThe Business Pr

10、ocess Management Initiative (BPMI) has developed the Business Process Modeling Notation (BPMN). This notation is particularly useful to visualize BPEL processes.BPMN 23 is now maintained by the OMG. Unfortunately, one could reproach to BPMN its lack of formalism, as explained by Wohed et at. in 24.

11、Although BPMN is an interesting solution, we preferred to extend UML 2.0 to achieve the same purpose. Indeed, UML was already used as a Process Modeling Language (PML) 9, 13, 16.As a matter of fact, UML has some very interesting features as a PML: it is standard, graphical, popular and it contains s

12、everal diagrams which allows to model different views of a system.UML was already considered to describe Web services composition. In 20, an approach using UML activity diagrams to do so was presented by Skogan et al.They provide a way to model the coordination and the sequencing of the interactions

13、 between Web services. They also explain how UML activity diagrams can be converted into BPEL 1 or in WorkSCo 3.However, in this approach, methods input/output and data transformation are modeled in notes (i.e. comments) on the side of the workflow, which can get quite confusing when the composition

14、 flow gets complex.Chunming Gao et al. also present in 11 a non-graphical way to model Web services composition with some mobility and time constraint. To do so, they introduce Discrete Time Mobile Ambient calculus (DTMA), an extension to the formal model called Mobile ambients calculus 5. Using DTM

15、A, they focus on modeling BPEL operations. Due to their non-graphical nature, languages such as DTMA are less user-friendly than graphical like UML.Another approach to Web services composition modeling was proposed by De Castro et al in 6. In their work, they make use of the behavior modeling method

16、 of MIDAS, a Model-Driven Architecture (MDA) framework 14. MIDAS is a model-driven methodology for the development of Web Information Systems (WIS) based on the MDA 21, proposed by the OMG 2. They introduced Web services composition through UML activity diagrams in their paper. However, the model is

17、 not detailed as much as necessary to allow code generation as BPEL. Some features could also be added such as data transformation and flow control mechanisms.In 12, Hamadi et al. put forwards Petri nets 17 based algebra for composing Web services. Petri nets are a well-known process modeling techni

18、que. The pros of using such Petri net based algebra is that it allows the verification of properties and the detection of inconsistencies. However, Web services need to be expressed using algebra constructs before being translated into a Petri net representation, adding consequently another necessar

19、y stage in the process.UML-S transformation rules from WSDL 2.0 and to WS-BPEL 2.0 were provided in 8. UML-S activity diagrams verification and validation using Petri nets was also detailed in 15.3. Web services composition model requirementsIn this part, we state what the requirements for a good We

20、b services composition modeling language. First of all, it is better to extends an already existing, well-known standard if it is adapted instead of coming up with a new model. UML modeling language is the de facto industry standard. Therefore it is a good candidate to be extended for Web services c

21、omposition modeling. Moreover, UML is widely used and its graphical models are easily understandable. The modeling language should allow to represent Web services interfaces as well as the dynamism induced by their composition. UML class diagram is particularly adapted to represent interfaces. Addit

22、ionally, UML activity diagram is a excellent candidate to model Web services composition, due to its strength to represent the dynamic. A good modeling language can also be judged by its simplicity and its clarity. Graphical languages such as UML are known for being user-friendly. Finally, it is wor

23、th noting that a composite Web service simply calls other services and makes them interact. Therefore, there is not a lot of programming involved compared to usual Web services. As a consequence, a composite Web services code can be generated in its totality from highlevel graphical models such as U

24、MLs. 4. UML-S: UML for Services The main contribution of this paper is ”UML-S: UML for Services”, an extension to UML 2.0 that allows for modeling Web services as well as their interactions. In UML-S, both class diagrams and activity diagrams are used to model and specify respectively Web services a

25、nd their interactions. In part 4.1, we present UML-S extended class diagram. After that, the activity diagram proposal is detailed in part 4.2.建模和使用UML-S Web服务组合的规范摘要随着Web服务组合引起了越来越多的兴趣，大部分研究工作解决了实现和执行的问题。因此，在过去的几年里许多组成语言（BPEL，XLANG，WSFL，WSCI，仅举几例）已经提出。然而，这些语言的一个弱点在于，它们很难在早期的发展阶段如说明书中使用。在本文中，延伸到UML2

26、.0叫做“UML-S：UML的服务”介绍。 UML-S允许Web服务模型驱动工程（MDE）和它们之间的相互作用。1.介绍现在很多公司都使用Web作为平台与合作伙伴进行沟通。互联网和它的技术，使他们能够提供给个人的Web服务以及其他业务。在Web服务模式的主要挑战是他们的发现和它们的组成。换言之，必须能够找到合适的Web服务对于给定的工作。这一过程被称为发现18，19。第二个挑战是在本文讨论的之一。它被称为Web服务组合4,10。在Web服务组合，已定义的服务一起用来实现更大的工作，从而生成了新的复合和增值的Web服务。为了实现这个目的，一个常见的方法是允许Web服务交互场景中通过使用消息传递机

27、制。尽管很多研究工作处理Web服务交互,其中大部分是解决语言,实现或应用程序问题,忽视了开发过程的早期阶段,如规范。为了解决这个问题,一个扩展UML 2.0称为“UML-S:UML服务”。UML-S允许Web服务以及它们的交互建模。统一建模语言（UML）已经由对象管理组织（OMG）2以图形化表达系统的开发模式定义。UML-S使开发人员通过下面的模型驱动架构（MDA）的原则来构建组合Web服务。因此,可以从高级UML-S模型生成特定于平台的代码。本文的结构如下。第二节提供了一个现有的调查方法模型的Web服务交互。在第三节,要求良好的Web服务组合建模语言。然后在第四节提出了UML-S的细节。之后

28、,提供了一个案例研究在第五节观察UML-S行动。最后,第六节吸引了结论并提出了未来的工作。2.相关工作业务流程管理计划（BPMI）开发了业务流程建模符号（BPMN）。这种表示法是特别有用的可视化BPEL流程。BPMN23现在由OMG维护。不幸的是，一个Wohed等的解释可以责备BPMN缺乏形式主义。在24。尽管BPMN是一个有趣的解决方案,我们更倾向于扩展UML 2.0来达到相同的目的。事实上,UML已经用作一种过程建模语言(PML)(9、13、16)。作为事实上，UML有一些非常有趣的功能作为PML：它是标准的，图形化的，流行的，它包含几个图表，允许模型系统的不同视图。UML已经被认为是描述

29、Web服务组成。在文献20，由Skogan等提出了使用UML活动图这样做的方法。它们提供了一种方式来协调和Web服务之间的交互的测序建模。他们也说明UML活动图可以被转换成BPEL1或WorkSCo3。然而,在这种方法中,方法的输入/输出和数据转换建模在notes(即评论)上的工作流,当组成流程变得复杂时会得到相当混乱的结果。高春明等人也展示了11Web服务组合与一些流动性和时间约束模型非图形的方式。为此，他们引进离散移动环境演算（DTMA），一个扩展名为手机的正式型号ambients演算5。他们使用DTMA集中于建模BPEL的操作。由于其非图形特性，语言如DTMA，不太人性化比的图形，如UM

30、L。德卡斯特罗等提出了另一个Web服务组合建模方法6。在他们的工作,他们利用MIDAS的行为建模方法,模型驱动体系结构(MDA)框架14。MIDAS是一个模型驱动的方法发展的网络信息系统”(感知)基于OMG提出的2MDA21。他们在论文中通过UML活动图引入了Web服务组合。然而，该模型没有详细尽可能必要允许代码生成作为BPEL。也可以添加一些功能如数据转换和流控制机制。在12,Hamadi等人提出了基于Petri网17的代数组合Web服务。Petri网是一个著名的流程建模技术。使用这种基于Petri网的代数的优点是它允许验证的属性和不一致性的检测。然而,Web服务需要使用代数表示构造被翻译成

31、佩特里网表示,因此之前添加另一个必要的阶段。从WSDL 2.0和ws - bpel 2.08中提供了UML-S转换规则。UML-S活动图验证和确认使用Petri网也有详细介绍。3.WEB服务组合模型的要求在本部分中，我们陈述一个好的WEB服务组合建模语言的要求。首先，最好是延伸一个已存在的、著名的标准，如果它适于取代想出一种新的模式的话。UML语言是事实上的行业标准。因此，这是一个用于延长WEB服务组合建模的很好的选择。此外，UML应用广泛，它的图形模型是易于理解的。建模语言应该允许代表Web服务接口以及活力成分诱导。UML类图特别适应代表接口。此外,由于其强度来表示动态,UML活动图是一个优

32、秀的候选人模型的Web服务组成。一个好的建模语言，也可通过其简单性和其清晰度判断。图形语言，例如UML，以人性化而著称。最后，值得一提的是，复合Web服务简单地调用其他服务，使他们互动。因此，相比通常的Web服务编程没有涉及很多的编程。其结果是，复合Web服务的代码可以从高标准的图形模型如UML全部产生。Design and Application of Collaborative Learning System based on Web to Database Experiment TeachingAbstract-The course of SQL Server Database Design and Management is an experiment course that contributes to cultivate the experiment ability of students, which is a supply to the database theory teaching. The collaborative learning is an effective method to progress the