基于服务的Agent社会组织研究

Web Service应用上的人工架构模式成为了其被高度重用的瓶颈。通过Agent对Web Service的封装能极大地改善WebService资源在应用上的主动性及智能性。针对Web Service封装后所形成的Agent服务,给出了基于服务本体及Agent服务描述语言(ASDL)的服务发现方法,并在此基础上给出了基于服务的Agent社会组织机制。实际应用证明方法可行有效。     

服务关系及其在面向服务计算中的应用

在面向服务计算模式中,传统的UDDI、ebXML服务注册中心无论是服务发现,还是组合与交互方面都面临着信息共享和过程中介的难题.文中结合语义Web(Semantic Web)和社会化网络(Social Networking)技术,显式地定义服务间的交互关系(简称服务关系),并将它们融入到服务注册中心的组织、构建及服务计算过程中,将可用Web服务组织成具有丰富语义信息、基于业务上下文和交互关系的服务生态系统.文章首先分析并定义了参数、操作和服务三个层级的服务关系;接着详细讨论了服务关系挖掘的技术细节,包括Web服务的语义标注、服务关系提取、利用等;最后是相关实验数据及结果分析.将语义推理和关系演算引入到服务发现、组合、交互过程中,可以促进和便利服务计算,也是朝向服务互联网(Internet of Services)迈出的重要一步.     

Combining query-by-example and query expansion for simplifying web service discovery

The vision of a worldwide computing network of services that Service Oriented Computing paradigm and its most popular materialization, namely Web Service technologies, promote is a victim of its own success. As the number of publicly available services grows, discovering proper services is similar to finding a needle in a haystack. Different approaches aim at making discovery more accurate and even automatic. However they impose heavy modifications over current Web Service infrastructures and require developers to invest much effort into publishing and describing their services and needs. So far, the acceptance of this paradigm is mainly limited by the high costs associated with connecting service providers and consumers. This paper presents WSQBE+, an approach to make Web Service publication and discovery easier. WSQBE+ combines open standards and popular best practices for using external Web services with text-mining and machine learning techniques. We describe our approach and empirically evaluate it in terms of retrieval effectiveness and processing time, by using a data-set of 391 public services.     

Research on dynamic business composition based on web service proxies

Web services-based business composition brings a number of advantages to the enterprise application development. How to select and compose the web services based on their functionality and QoS (Quality of Service) dynamically prove to be more and more important. In this paper we develop a proxy-based framework to compose Web services dynamically. The framework is featured with a QoS model, an effective service discovery and selection algorithms to facilitate the dynamic integration of Web services and management of abnormalities. Furthermore, a business process constructing method based on service slice is put forward to satisfy the users’ personalized requirements more effectively and flexibly. Our study concerns both functionality and QoS characteristics of Web services to identify the optimal business process solutions. A Complete case study is also included in this paper and the performance demonstrated that the framework and algorithms can provide a tangible and reliable solution to dynamic Web service composition and adaptation.     

一种基于语义的Web服务匹配算法

概要:在当前Web服务发现过程中,采用基于数据类型和关键词的搜索匹配算法,而忽略了人类语言表达的多样性。通常服务请求者对需求描述不能很好符合Web服务匹配算法的要求,是造成服务匹配率较低的主要原因。本文探讨一种基于语义的Web服务匹配算法,分别对服务提供者注册Web服务,服务请求者提交Web服务请求以及服务注册中心进行Web服务匹配等三个过程提出了改进算法,从而可提高服务匹配率。     

一种支持QoS的自适应Web服务发现模型

服务质量是Web服务发现中的关键问题.该文提出一种支持QoS的自适应Web服务发现模型,在满足用户对Web服务功能需求的基础上,依据QoS等非功能性指标对Web服务进行选择和排序,并给出服务的选择排序算法,该算法以服务注册参数、用户反馈信息和实时监测数据为依据,能动态地对服务的非功能性指标进行评价,返回最合适的服务给用户.实验证明,该模型有效地提高了系统的可用性.     

A trustworthy QoS-based collaborative filtering approach for web service discovery

Many network services which process a large quantity of data and knowledge are available in the distributed network environment, and provide applications to users based on Service-Oriented Architecture (SOA) and Web services technology. Therefore, a useful web service discovery approach for data and knowledge discovery process in the complex network environment is a very significant issue. Using the traditional keyword-based search method, users find it difficult to choose the best web services from those with similar functionalities. In addition, in an untrustworthy real world environment, the QoS-based service discovery approach cannot verify the correctness of the web services’ Quality of Service (QoS) values, since such values guaranteed by a service provider are different from the real ones. This work proposes a trustworthy two-phase web service discovery mechanism based on QoS and collaborative filtering, which discovers and recommends the needed web services effectively for users in the distributed environment, and also solves the problem of services with incorrect QoS information. In the experiment, the theoretical analysis and simulation experiment results show that the proposed method can accurately recommend the needed services to users, and improve the recommendation quality.     

基于QoS的Web服务发现方法

由于传统的基于关键字和简单分类的Web服务发现机制较少考虑服务质量(QoS),因此不能很好地满足用户的需求。针对该问题,提出一种基于QoS的Web服务发现模型,通过引入QoS代理机制以支持基于QoS的Web服务发布与发现。在此基础上,根据不同用户的QoS需求,提出一种基于QoS的Web服务发现算法。实验结果表明,该算法具有较高的准确率。     

基于抽象服务和概率的服务发现方法

服务匹配是Web服务发现中的一个重要部分.随着Internet上Web服务的日益增多,如何从海量的服务中,迅速地找到令请求者满意的Web服务是研究者追求的目标.提出抽象服务的概念,提高了服务发现效率;给出了一种基于概率的Web服务选择算法,考虑了Web服务使用历史,让服务请求者在较短时间内得到所需的Web服务.     

METEOR-S WSDI: A Scalable P2P Infrastructure of Registries for Semantic Publication and Discovery of Web Services

Web services are the new paradigm for distributed computing. They have much to offer towards interoperability of applications and integration of large scale distributed systems. To make Web services accessible to users, service providers use Web service registries to publish them. Current infrastructure of registries requires replication of all Web service publications in all Universal Business Registries. Large growth in number of Web services as well as the growth in the number of registries would make this replication impractical. In addition, the current Web service discovery mechanism is inefficient, as it does not support discovery based on the capabilities of the services, leading to a lot of irrelevant matches. Semantic discovery or matching of services is a promising approach to address this challenge. In this paper, we present a scalable, high performance environment for Web service publication and discovery among multiple registries. This work uses an ontology-based approach to organize registries into domains, enabling domain based classification of all Web services. Each of these registries supports semantic publication and discovery of Web services. We believe that the semantic approach suggested in this paper will significantly improve Web service publication and discovery involving a large number of registries. This paper describes the implementation and architecture of the METEOR-S Web Service Discovery Infrastructure, which leverages peer-to-peer computing as a scalable solution.     

基于抽象服务流程构建集成组件

提出了一种基于抽象服务流程构建集成组件的方法,并运用工作流模式和集成组件实现服务组合的重用,确保了Web服务组合流程设计的正确性及简洁性,同时增加了Web服务组合的可靠性和重用性。     

基于资源本体的Web服务发现与组合研究

将语义Web技术引入Web服务研究,提出一种基于资源本体的Web服务发现和组合方法。通过分析资源之间关系,建立了基于上下位资源查找的Web服务发现方法;通过分析资源与服务的输入输出关系,建立了一种逐级查找的Web服务组合方法。与基于关键字和Web服务语义的Web服务发现和组合方法相比,基于资源本体的方法能较好地满足服务查全率和查准率的要求,具有较高的组合质量和效率,非常适合与资源密切相关的Web服务。     

基于网关服务缓存和QoS的服务发现机制

在服务描述语言上增加QoS描述,通过QoS认证中心管理和量化服务的QoS属性,实现Web服务的QoS属性描述。在此基础上,设计一种基于网关服务缓存和QoS的服务发现机制,通过代理服务网关对Web服务进行筛选,同时维护一个虚拟服务缓存管理历史服务请求信息,减少服务请求过程中重复的服务发现过程,提高服务发现性能,并通过实验验证其正确性和有效性。     

基于语义描述的分布式Web服务发布与发现

结合P2P与Web服务语义描述技术，提出了一种基于分布式哈希表的非集中式Web服务发布与发现方法。通过定义服务供求双方共同遵守的领域本体，实现具有同样语义概念的两种不同描述的统一，提高服务发现的效率和准确度。利用类别本体对领域本体的组织，提出了层次式Web服务目录系统。基于该系统，服务的发布与发现是在特定应用领域范围内进行，因此减少了服务搜索空间，提高了服务发现的效率。     

基于QoS的可信Web服务组合研究

如何合理、高效地选择和组合众多功能相似的服务,为用户提供更优质的服务,是当前SOA领域研究的重点和难点。服务质量QoS(Quafity of Service)的引入,在一定程度上保证了服务组合的合理性,但对于如何确保服务组合的可信,目前还没有一个比较完善和可行的方案。因此,提出了可信Web服务组合模型(Trust Web Service Composition Modcl,TWSCM),并通过在原有Wcb服务体系架构上增加QoS代理和可信模块来确保服务组合的质量和可信。最后,在语言网格上进行了相关实验,结果表明,该方法能为用户提供高质量、可信的组合服务,从而验证了该方法的合理性和有效性。     

服务流程检索技术研究

服务重用的目的是提高软件开发的效率,然而,现有的服务重用方法局限于原子服务的重用。如何重用任意粒度的服务流程片段（Service Flow Fragment,SFF）是一个更具实用价值的问题。提出一种新颖的索引（Changeable Level Index,CLI）,它通过所构造的服务标签合并树（Service Label Merge-tree,SLM-tree）组织服务流程,同时实现原子服务及组合服务的检索,从而最大限度地提高它们的利用率,并且能够择优返回检索结果。为验证所提出方法的可行性和有效性,通过Web Service Challenge Testset Generator（CTG）构造了一个包含20万流程,1.05亿原子服务的数据集。实验结果表明,提出的方法具有很高的性能。