基于本体的Web服务描述与发现机制研究

Web服务发现是Web服务系统架构的重要组成部分,传统的服务发现只是简单的基于关键词的语法匹配,查询得到的服务往往不是用户想要的。分析了国内外Web服务描述与服务发现现状,提出了一种具有层次性和结构性的Web服务描述与发现算法。实验证明该算法与现有算法相比具有较好的查准率和查全率。     

Web服务访问控制规范及其实现

提出了一种用于Web服务的访问控制模型,这种模型和Web服务相结合,能够实现Web服务下安全访问控制权限的动态改变,改善目前静态访问控制问题。新的模型提供的视图策略语言VPL用于描述Web服务的访问控制策略。给出了新的安全模型和Web服务集成的结构,用于执行Web服务访问控制策略。     

Efficient execution of composite Web services exchanging intensional data

Web service technologies provide a standard means of integrating heterogeneous applications distributed over the Internet. Successive compositions of new Web services using pre-existing ones usually create a hierarchical structure of invocations among a large number of Web services. For the efficient execution of these composite Web services, we propose an approach which exploits intensional XML data, i.e. an XML document that contains special elements representing the calls to Web services, in order to delegate the invocations of the external Web services to some relevant nodes. We formalize an invocation plan for composite Web services in which intensional data is used as their parameters and results, and define a cost-based optimization problem to obtain an efficient invocation plan for them. We provide an A∗ heuristic search algorithm to find an optimal invocation plan for a given set of Web services and also present a greedy method of generating an efficient solution in a short time. The experimental results show that the proposed greedy method can find a close-to-optimal solution efficiently and has good scalability for a complex call hierarchy of Web services.     

基于IOQ模型的Web服务组合算法

提出一种IOQ模型及在该模型下求解构成复杂服务的各个子服务的算法,将该类服务组合问题转化为简单问题,即在满足QoS约束的服务集合中,已知服务的输入集合和输出集合,利用输出集合倒序查找各子服务及其输入集合。针对该类服务组合问题,给出算法模型及求解问题算法的伪代码。     

Knowledge Systems and Global Advertising Services

This paper explores the contribution of global advertising services to the creation and dissemination of knowledge through an examination of their role in knowledge systems at a national and international level. The aim is not only to gain an understanding of global advertising services as bridges between national knowledge systems but also to examine how such services shape the institutions that constitute a knowledge system. In this way, an appreciation of the contribution of advertising services, and knowledge intensive services (KIBS) more generally, to the knowledge creation and distribution process will be developed.     

Web服务的控制集成

在软件集成的研究中,控制集成是一个重要的组成部分,研究了Web服务的控制集成,提出了Web服务的包容模型与聚合模型,包容模型使用容器对Web服务进行封装,对外提供统一的服务访问接口,Web服务消费者通过该接口访问Web服务;聚合模型使用聚合器对Web服务进行管理,聚合器本身不参与Web服务调用,它向Web服务消费者提供Web服务的链接,Web服务消费者在从聚合器处获得链接后再访问相应的服务,其成果已经在一个原型系统中得到了验证.     

Web服务安全性测试技术研究

Web服务的应用越来越广泛,Web服务中的安全缺陷与漏洞也在不断增多,Web服务安全性问题日益突出。Web服务安全性测试是保证Web服务软件安全性、降低安全风险的重要手段。本文提出了一种Web服务安全性测试框架,论述了Web服务主要的安全功能需求、实现标准及实施安全功能测试的一般原理,并从攻击Web服务的角度对Web服务安全漏洞测试进行了系统介绍,分析了Web服务常见的安全漏洞及测试方法。     

Experiences in developing mobile applications using the Apricot Agent Platform

The trend of increasing mobile services has set a new challenge for service providers: how to develop more advanced and user-friendly, context-aware and personalized mobile services for the users. Apricot Agent Platform is an agent-based software platform designed for developing context-aware and personalized mobile services. Apricot Agent Platform supports the development of user-friendly mobile services by providing tools for combining various mobile and Internet-based services. Apricot agent architecture consists of an agent platform, agents and agent containers. For the developers of mobile services, it provides built-in functionality and communication mechanism. Furthermore, this paper describes four demonstrators that are built up on the Apricot Agent Platform to evaluate the usability and efficiency of the platform in the processes of building mobile services. The outcome of the evaluation indicates relatively promising results and the further target for development is revealed.     

The perceptions towards mobile services: an empirical analysis of the role of use facilitators

The adoption patterns for new technology such as mobile services are essential to understand for developing them further. Hence, it is important to study how willing people are to try new mobile services and do variables, which facilitate the use of the services have an effect on the consumers’ perceptions of the services and their adoption readiness. This study analyses how the familiarity of mobile devices, the time the services are initially used and users’ technology skills affect the initial mobile service usage experience and the likelihood of continuous usage. The results show that the duration of the use does not effect consumers’ perceptions about mobile services, but familiarity of the device and user skills have an impact on the perceptions of the services.     

P2P环境下基于语义的Web服务组合研究

利用OWL-S语言描述Web服务,在组合操作中加入语义信息,实现了Web服务组合的自动化。为了提高Web服务的搜索速度,采用Chord路由算法。构建了一个P2P环境下基于Chord网络的Web服务组合模型,在其上实现了基于语义的Web服务组合,最后通过实例给出了语义Web服务自动组合过程。     

Web服务行为兼容性的判定与计算

确保Web服务行为兼容是实现Web服务无缝集成与协作的一个重要问题.在服务视图概念的基础上,给出了Web服务行为兼容性的相关定义.提出一种基于π演算的Web服务行为兼容性的定性判定与定量计算方法.该方法首先通过算法自动地将Web服务行为和Web服务间的交互行为表达成π演算进程,然后借助π演算的操作语义和形式化推演实现服务行为兼容性自动的定性判定;随后在π演算的进程变换理论的基础上提出算法实现服务兼容性自动的定量计算.该方法在服务动态组合与服务动态替换中的典型应用表明,该方法对于服务组合的正确建立和可靠执行具有重要作用.     

Scripting JAX-WS [JavaScript]

This article describes an integration of the ECMAScript programming language commonly known as JavaScript, with an implementation of the Java API for XML Web services (JAX-WS) 2.0. The JAX-WS 2.0 specification - the new version of the for XML-Based RPC (JAX-RPC) defines standard APIs and approaches for building Java-based Web services. As its name implies, JAX-RPC was concerned mostly with how to implement RPC-oriented Web services in Java. JAX-WS expands and improves on the specification in several ways, including tying together and updating its sup port for several base Web services specifications, such as SOAP 1.2; providing a coherent design for using Java annotations to specify Web services metadata; providing support for document-oriented Web services, asynchronous services, and services that use transports other than HTTP; addressing implementation issues surrounding handlers, which are interceptors that provide hooks into message flows between senders and receivers; and describing practices for dealing with versioning in Web services.     

Web服务组合的可靠性动态评估模型*

为了合理、高效、动态地评估Web服务组合的可靠性,为服务请求者提供高质量的组合服务,提出了一个Web服务组合的可靠性动态评估模型。该模型对服务提供者发布至UDDI注册中心的Web服务进行语义预先处理,根据语义Web服务间的逻辑组合关系,基于预推理技术构造Web服务的自动组合框架,提出了Web服务的自动组合算法,建立Web服务组合方案的路径结构;利用随机Petri网对满足服务请求者需求的服务组合路径结构进行可靠性建模,结合在线获取的Web服务可靠性信息,对Web服务组合的可靠性进行动态评估。实验示例结果分析表明,提出的模型能确保Web服务组合方案的有效性和提高服务组合的效率,对Web服务组合的可靠性评估具有较强动态性和灵活适应性。     

Granularit?t von Services

Service-oriented architectures are widely discussed as a design principle for application and enterprise architectures. Nevertheless, an adequate granularity of services has not yet been researched sufficiently from an economic perspective. The finer the granularity to realize the functions of a process, the higher the number of services is, and the more effort has to be directed towards composing them. In contrast, very coarse-grained services bear the disadvantages of higher implementation costs and lower reuse potential (e.g., in different processes). The aim of the decision model proposed in this paper is to determine an adequate granularity of services from an economical perspective. Thus, degrees of freedom, which often exist for the choice of granularity after a domain analysis, can be leveraged to realize a cost-efficient solution. We illustrate the applicability and practical benefits of the decision model with an example from the context of a financial services provider.     

基于Ontology的地理服务描述

随着地理服务技术的发展,相应的地理服务的查询成为了一个重要的问题,其中一种解决方法是设计一种模块化的共享的Ontology来描述Web服务,并利用该Ontology进行服务查询。针对这个问题,该文提出了一种Ontology,它结合了已存在的各种不同的Ontology标准和元数据标准来描述地理服务。     

基于主动服务结点的分布式主动服务框架

主动服务结点既是服务的提供者,又是服务的使用者,具有自主移动计算和提供服务能力。主动服务结点采用私有UDDI和构件资源库,通过私有UDDI及WEB服务描述语言与UCDL之间的转换提供主动服务。文中结合基于私有UDDI的WEB服务模型和本地构件资源库方式,提出主动服务结点模型和基于主动服务结点的分布式主动服务框架,克服了基于UDDI框架的服务集中管理的问题。     

Web服务应用之初探

近年来,Web服务技术的应用发展得越来越快。Web服务是基于横跨Internet的分布式计算。它依赖于服务提供者描述他们的服务性能和服务请求者用一种明白的、理论上可解释的格式来描述。Web服务使用标准的如XML、SOAP和HTTP之类的网页协议。它最后向Web交互领域延伸。     

Auctions for ancillary services

This paper discusses the procurement of ancillary services in a competitive electricity market. The paper assumes the existence of an underlying market for energy and explains why this energy market must be accompanied by a market for ancillary services. ancillary services include services such as the provision of operating reserves and Automatic Generation Control (AGC) both of which can require infra-marginal generators to choose between supplying energy, or operating reserves and AGC. Ancillary services are crucial for the reliable operation of an electric power system under a regime of competitive generation. Structures for organizing competitive auctions for ancillary services are examined. Initial experience and potential pitfalls from a market using such auctions is also reported.     

Coordinating multiple agents for workflow-oriented process orchestration

Distributed component-based services and semantic web services are promising technologies for next generation inter-enterprise integration. The dynamic nature of this domain presents a complex problem for tools that intend to support this cross-organizational integration. However, the autonomy and adaptation of software agents represent a viable solution for the composition and enactment of cross-organizational services. Currently, there are few studies that measure the impact of the dynamic environmental effects on service composition. On an on-going basis, composite services or workflow processes of web services may be constantly changing in terms of responsiveness of services, accessibility of services and their meta-information, business process schema changes, etc. These conditions impact what interactions a team of agents must undergo to achieve a specific process derived of composite web services. This paper describes an approach, model, and supporting software toward the efficient design of interaction protocols for coordinating agent teams in the business process orchestration domain. This approach considers several environmental conditions related to the dynamism of the Internet.