一种基于Web服务的工作流过程模型

工作流管理系统实施是提高企业核心竞争力的有力措施,而工作流过程模型是整个工作流管理系统的基础,在Web服务的基础上提出了一种分层的过程模型,同时在过程模型中增加新的元素事务活动和事务节点,增加了模型对工作流管理系统的分布异构环境以及事务特性的支持.     

A layered architecture for flexible Web service invocation

Web service composition is emerging as an interesting approach to integrate business applications and create intra‐organizational business processes. Single Web services are combined to create a complex Web service that will realize the process business logic. Once the process is created, it is executed by an orchestration engine that invokes individual Web services in the correct order. However, Web services composing the workflow sometimes become unavailable during the run‐time phase, blocking process execution. This paper describes an architecture that allows the flexible orchestration of business processes. With this approach, Web services composing the process can be automatically substituted with other compatible Web services during process execution. A methodology is defined to evaluate Web service compatibility based on interface matching, in order to select substitutable Web services. Copyright © 2005 John Wiley & Sons, Ltd.     

基于Web services和BPEL实现企业应用集成

本文介绍了传统企业应用集成的架构,阐述了其存在的弊端,在认真分析Webservice和BPEL两大关键技术的基础上,提出了一种基于Webservices和BPEL技术实现企业应用集成的新架构,并给出新架构中关键部分的解决方案。     

A business model for deploying Web services:A data-centric approach based on factual dependencies

The standards XML, SOAP, WSDL and UDDI allow (i) services to be accessed and executed via the Web; and (ii) a loose coupling of these services. Thanks to these standards, Web services technology is becoming not only a de facto integration standard, but also a de facto Internet standard instance of the SOA architecture. However, the deployment of such a technology is still hindered by some technical as well as methodological issues. This paper proposes a business model with multiple interfaced abstraction levels as a framework to methodologically deploy Web services technology with respect to SOA architecture. The attributes describing the business objects and coordination artifacts as described in the highest abstraction level of the business model, i.e. the universe of discourse, are aggregated according to a time/space constraint called factual dependency. Each aggregation of factually dependent attributes is validated with regard to an actual business event. The aggregation is then interfaced to lead to a well-specified Web service. The resulting comprehensive set of consistent Web services are then registered in a public or a private UDDI to be discovered and invoked by any business process. The proposed Web services generation process aims at unlocking and turning informational assets into actions. It differs from the current IT perspective approaches that generate Web services directly from redundant and inconsistent elements in the enterprise information systems.     

基于QoS的Web服务选择算法综述*

服务选择算法是影响组合服务的QoS和服务组合性能高低的关键因素。针对近几年来基于QoS的Web服务选择算法的发展状况进行了综述,介绍和总结了当前基于QoS的Web服务选择问题模型,对服务选择策略进行了分类,并对当前的一些典型的基于QoS的Web服务选择算法进行了系统的分析和评论。最后指出了现有算法中的不足之处,展望了该领域的进一步研究方向。     

Web服务组合中基于 QoS的改进型遗传算法 *

提出了一种在 Web服务组合中基于 QoS的改进型遗传算法。该算法通过计算个体间服务质量的海明距离提高了服务组合的质量 ;通过指定用户总时间限制和实施优良解保留策略解决了算法运行时间对服务质量的影响问题。实验结果表明了算法的有效性。     

Web服务环境中的业务过程建模语言比较框架

基于Web服务的价值链集成越来越受到人们的重视,相应的业务过程建模语言成为研究的焦点,各具特色的业务过程建模语言不断出现,对语言的研究、分析和比较已经成为基于Web服务的信息系统集成研究和开发中的一个重要问题。该文在分析Web服务环境下系统集成的体系结构模型基础上,提出了一个Web服务环境下业务过程建模语言比较框架,作为验证,对常见的建模语言进行了比较分析和评述。     

一种Web服务环境下的事务保障框架

Web服务环境下的业务流程需要事务机制来保障其运行的可靠性和结果的一致性。本文分析了Web服务环境下事务的特点及挑战性问题,介绍了针对这些问题进行的相关工作。在综合这些工作的基础上提出了一个事务保障参考框架,并通过一个应用实例展现该框架如何支持业务流程的可靠运行。     

基于服务QoS执行信息的Web服务推荐研究

基于服务的非功能（QoS）特性进行服务发现是面向服务计算领域的一个研究热点。为了克服服务QoS难以获取且动态变化的特点,提出一种基于已往QoS执行信息的Web服务推荐方法。首先给出一种可以方便记录QoS执行信息的系统框架;然后描述了基于时间加权的服务推荐的匹配算法;实验结果表明该推荐方法是可行和有效的。     

Inclusive social tagging and its support in Web 2.0 services

This paper investigates the Web 2.0 phenomenon of social tagging in the context of existing approaches to semantic data structuring. Social tagging is embedded into the space spanned by current structuring approaches like taxonomies, meta-data, and ontologies in order to identify its semantic and pragmatic foundations. Thereby, we use the Inclusive Universal Access paradigm to assess social tagging with respect to socio-technical criteria for inclusive and barrier-free provision and usage of web services. As a result of this analysis we propose a concept we chose to call “Inclusive Social Tagging”. We subsequently use the requirements set forth by this concept to assess the tagging functionality of currently popular Web 2.0 services. We found that these services differ significantly in their implementation of tagging functionality, and we did not discover any service providing full compliance with Inclusive Social Tagging requirements.     

组合Web服务业务流程访问控制技术研究综述

业务流程访问控制是保证组合Web服务增值安全应用的关键技术,着重论述了组合Web服务业务流程访问控制技术的研究现状及问题。首先对组合Web服务业务流程安全需求进行了分析,然后从组合Web服务业务流程访问控制模型、业务流程运行时访问授权约束、业务流程协同访问授权的一致性检验3个方面分析了业务流程访问控制核心技术的研究进展。最后,结合已有的研究成果,指出了目前研究的挑战以及未来的发展趋势。     

Usage-based dynamic pricing of Web services for optimizing resource allocation

Web services technology is becoming an important technological trend in Web application development and integration. Based on open standards, such as SOAP, WSDL, and UDDI, Web services allow Web-based applications to communicate with each other through standardized XML messaging and to form loosely coupled distributed systems. Although the open feature of Web services benefits service providers in servicing consumers, the unlimited computing resources access of Web services to network bandwidth, storage throughput, and CPU time may lead to overexploitation of the resources when applications based on the Web services technology are widely accepted. Therefore, it is critical to optimize the operation of Web services, subject to the QoS requirements of service requests, to assure the total benefits of the service providers and the service consumers. This paper proposes a usage-based dynamic pricing approach to optimizing resource allocation of Web services in the principle of economics, and reports on a pilot implementation demonstrating the technical feasibility of the proposed approach.

基于树型编码遗传算法在Web服务选择中的应用

提出一种基于QoS的Web服务选择的遗传算法（TGA）。该算法采用树型编码,携带流程的静态模型结构信息,可实现染色体的自动编解码和存储适应值计算的中间结果,并且可以通过简单的方法有效支持组合服务运行时重计划。通过仿真实验,验证了在同等优化效果下,TGA比一维编码遗传算法获得了更快的速度,并验证了树型编码用于流程运行时重计划的有效性。     

面向QoS全局优化的大规模Web服务组合方法

把多个简单Web服务组合成为更强大的组合Web服务是面向服务计算的目标之一。由于存在多个功能相同但服务质量属性不同的候选Web 服务,因此需要针对服务质量要求进行服务组合。鉴于Web服务组合规模的不断增长和特定领域的时限要求,面向实时大规模Web服务组合问题的快速收敛算法尤为重要,然而目前相关工作还很少。论文提出一种新的Web服务组合算法GAELS（Genetic Algorithm Embedded Local Searching）,运用高适应度初始种群和局部搜索的变异策略,加快收敛速度。通过实验评测表明与简单遗传算法相比,GAELS算法能更快得到近似最优解,且随着服务规模增长,拥有更好的适应性。     

Web服务相容性的形式化描述与分析

Web服务的相容性分析是为了保证多个Web服务之间的正确交互。基于Pi-演算对Web服务的相容性进行了形式化的分析,给出了二个Web服务之间相容性的两个形式化定义。同时定义了二个Web服务进程之间的投影操作,在此基础上给出了多个Web服务之间相容性的形式化定义。     

Smart marketplaces: a step beyond Web services

This paper identifies a new form of Internet intermediaries called smart marketplaces. Beyond other online marketplaces and strategic alliances, a smart marketplace provides an infrastructure and various core service components to facilitate the real-time integration of Web services. The structure of smart marketplaces and potential players are discussed. We analyze the business value of service integration offered by a smart marketplace, and further investigate the competition within and between smart marketplaces. Research supported in part by Intel.     

Representations for semantic learning webs: Semantic Web technology in learning support

Abstract Recent work on applying semantic technologies to learning has concentrated on providing novel means of accessing and making use of learning objects. However, this is unnecessarily limiting: semantic technologies will make it possible to develop a range of educational Semantic Web services, such as interpretation, structure-visualization, support for argumentation, novel forms of content customization, novel mechanisms for aggregating learning material, citation services and so on. In this paper, we outline an initial framework that extends the use of semantic technologies as a means of providing learning services that are owned and created by learning communities.     

一种基于QoS全局最优的服务选择算法*

现有的服务选择算法存在低效、非全局最优等缺点。针对现有算法的不足,提出了一种基于QoS的高效服务选择算法。首先建立服务选择问题的多目标优化模型,之后用改进的多目标粒子群算法(IDMPSO)求解该模型,从而获得一组高质量最优解。在IDMPSO中,通过计算粒子的密集距离来进行Pareto最优解的保留,并把密集距离与欧几里德距离结合起来提出一种全局最优粒子选取的方法。实验结果表明,IDMPSO得到的解相对较优,且分布均匀,并且随着问题规模的增加,运行时间呈线性增长。     

基于历史用户QoS感知的Web服务发现方法

目前的Web服务发现方法,由于没有充分利用用户情境信息,导致在服务发现时间和结果准确率方面存在不足。首先对包括当前用户在内的情境相似的用户进行了聚类,缩小了服务发现的范围;然后,在此基础上利用当前用户偏好信息及情境相似的历史用户感知到的候选服务的QoS数据,给出了一种基于历史用户QoS感知的Web服务发现方法,包括候选服务的QoS数据获取和综合权重计算;最后,结合实验并与其他Web服务发现方法进行比较,证明了该方法在服务发现结果的准确率和时间效率方面均有了一定的提升。     

基于QoS的语义Web服务组合研究

Web服务技术与语义网技术的发展,产生了一个新的研究领域——语义网服务。语义网服务利用本体技术增强了Web服务的语义表达能力,使服务的发现与执行,组合与交互更加自动智能化。关注Web服务的非功能属性,即服务的QoS属性,研究分析了基于QoS的语义网服务组合工作,提出了一个Web服务的QoS本体模型,并讨论了该模型在语义网服务组合工作中的应用。