Towards the Semantics and Verification of BPEL4WS

In this paper, we discuss the semantics of BPEL4WS language which is a de facto standard for specifying and execution workflow specification for web service composition and orchestration. We propose a language μ-BPEL that includes most primitive and structured activities of BPEL4WS, and define its semantics. As the Timed Automata (TA) is powerful in designing real-time models with multiple clocks and has well developed automatic tool support, we define a map from μ-BPEL into composable TA. Therefore, the properties we want to check can be verified in TA network correspondingly. Furthermore, we prove that the mapping from μ-BPEL to TA is a simulation, which means that the TA network simulates correctly the corresponding μ-BPEL specification. The case study with model checker Uppaal shows that our method is effective, and a Java supporting tool based on Uppaal model checker engine has been developed.     

An exploratory study of the accessibility of state government Web sites

This paper focuses on Web accessibility. Relevant legislation and judicial decisions are reviewed, and prior empirical research is presented. This study presents the results from the Web accessibility analysis of the home pages of the 50 states and the District of Columbia. It found that twenty-nine percent of the home pages do not meet the requirements for Conformance Level A Web accessibility. Only one state meets Conformance Level AA standards, which are the minimum standards recommended for Web accessibility, and no state meets Conformance Level AAA standards. This paper also discusses how to address common accessibility problems.

On the efficiency of keyboard navigation in Web sites

An efficient keyboard access to Web sites is highly important for many groups of disabled users. However, the current design of most Web sites makes the efficient keyboard navigation nearly impossible. This paper investigates the performance of the keyboard and mouse navigation in Web pages. The comparison is based on the theoretical arguments and on two small studies. The results show that the current amount of keyboard support in common Web sites is far from being sufficient. Typical problems concerning keyboard support in Web sites are discussed, along with possible solutions and the related constraints.

企业门户Web资源整合及其实现的研究*

讨论了企业门户Web资源整合中的关键问题,分析并给出了相关整合技术方案。提出了一种特殊的远程门户组件Web服务（WSRP）实现机制WA2WP（Web Application to WSRP Portlet）,可将普通Web网站映射封装为虚拟门户组件发布;给出了改进的跨域单点登录机制SSO4EPI（Single Sign On for Enterprise Portal Integration）,可提供开放的接口形式和对跨安全域异构性的良好支持。最后结合应用实例说明以上方法的可行性和推广价值。     

异构系统集成中基于WS Addressing的消息安全转发方案

由于Web Services原有的消息寻址规范WSRouting存在安全隐患,W3C制定了WSAddressing规范,用于替代WSRouting。提出一种基于WSAddressing规范的解决方案,使用一致的寻址模式发送事件消息来实现消息级的安全,提高异构系统集成的安全性。     

基于XML数据库的Web应用研究*

使用XML作为数据库存储数据,是XML应用的重要领域。讨论了如何用XML数据库系统进行Web应用开发设计的相关技术,如XML数据库、XML文档及其有效性定义、数据转换链接和Web平台搭建等。     

ASP平台上基于Web Service的插件技术的实现

以国家“863”项目面向网络化制造的AsP(Application Service Provider)平台开发及应用为背景,针对在ASP平台提供应用服务需使用平台提供的插件来实现集成从而达到无缝连接这一要求。着重探讨了基于Web Service的插件技术的实现原理,并给出在ASP平台上实现的一个实例。     

基于DCOM的分布式Web模型研究

从传统软件业所面临的挑战出发,分析总结了传统的解决方案及其局限性。根据目前的分布式模式现状,结合当前组件技术和Web技术的发展趋势,详细阐述了基于DCOM的分布式Web模型的原理。     

Linux环境下基于Web的信息系统建设研究*

通过比较分析目前流行的基于Web的信息系统建设方案所采用的关键技术,提出了基于Linux的Apache,JSP和Oracle的网站建设方案,并介绍了一个基于Linux的Apache,JSP和Oracle的网站建设实例——农产品供求信息分析与预测系统,显示了这一方案的明显优越性。     

一种基于Agent适用于Web应用的软件抗衰方法*

“软件衰退”引起的计算系统失效是影响系统可靠性的一个重要方面,“软件抗衰”技术作为一种有效的预防、减缓软件衰退的手段已经日益引起人们的关注。介绍了软件抗衰技术,并针对Web应用的特点,提出了一种基于Agent的软件抗衰方法。实例表明,这种方法计算强度小、效率高,具有明显的优势。