【作者】 沈桂芳；

【导师】 李心科；

【作者基本信息】 合肥工业大学 ， 计算机软件与理论， 2008， 硕士

【摘要】 普适计算模式的发展带来的上下文感知计算已经逐渐延伸到SOA架构下的Web服务及服务组合领域。现有的Web服务组合引擎一方面多属于人工合成的模式,灵活性不高;另一方面都没有将感知上下文纳入组合策略的考虑范畴,会返回很多无效的结果,组合应用效率低,可适应性差。本文详细分析了Web服务组合的上下文感知,将上下文感知应用到Web服务组合中,并提出了一种面向感知上下文的Web服务组合引擎WSCETCA。通过对Web服务组合流程的详细分析,将Web服务组合中的上下文分为以下五类:服务实例上下文I-Context、服务上下文W-Context、复合服务上下文C-Context、基于服务质量的上下文Qos-Context和用户上下文User-Context,并利用OWL-S来描述这些上下文信息。将上下文信息嵌入到SOAP的header头块进行传递发送,并设计了上下文管理器及上下文数据库来存储管理驱动这些上下文信息,同时对UDDI进行语义扩展,提供服务及服务语义信息地注册、服务查询的语义接口,从而实现一种上下文感知的服务查询、匹配及优化组合。采用Eclipse、Jena Framework、Apache Axis等开发工具开发了一个引擎原型,结合一个上下文感知应用实例,利用Protégé3.4 beta开发本体库来支持应用,以验证该组合引擎的功能。最后,通过测试引擎响应不同长度的SOAP消息和不同数量的并发用户的响应时间,得知本引擎随着所传递消息长度的递增以及当前用户数的递增,系统运行较平滑稳定。更多还原

【Abstract】 The Context-aware computing developed with Ubiquitous or Pervasive Computing has extended into Web service and web service composition of SOA. On the one hand, the current web service composition engines are manual mode and lack of flexibility. On the other hand, they don’t take the context into account in composition strategy, so they may return some unnecessary result, the efficiency and adaptability of composition application is low.This dissertation analyzes the context-aware in web service composition and presents a web service composition engine WSCETCA towards context-aware. The context in web service composition can be classified by analyzing the process of web service composition: the context of web service instance(I-Context),the context of web service(W-Context), the context of composited service(C-Context), the context based on quality of services(Qos-Context), the context of users(User-Context), and the information of context is described by OWL-S. The Context information is embeded in header of SOAP to transfer. Context manager and context database are designed to store、control and drive these context information. Services, semantic information of services register and semantic interface of services discovery are provided by expanding UDDI semantically. Consequently, an effective service discovering, matching and compositing towards context-aware can be achieved.An engine prototype is developed by some tools, such as Eclipse, Jena Framework, Apache Axis etc. By an application example of context-aware, the ontology is developed to supply the application by Protégé3.4 beta to validate the function of WSCETCA. Finally, a conclusion that WSCETCA can run smoothly with the increasing of the length of the transfering message and the number of current online users by testing the responding time of the SOAP messager with different length and online users with different number.更多还原