普适计算中基于语义的服务发现

【作者】 袁海燕；

【导师】 罗惠琼；

【作者基本信息】 电子科技大学 ， 计算机系统结构， 2005， 硕士

【摘要】 普适计算是继主机计算、桌面计算之后计算模式的第三次革命,在普适环境中根据需求定位设备或服务是一项具有挑战性的工作。服务发现是普适环境中的重要研究领域,本文系统地分析与比较了现有的主流服务发现协议,包括Jini、UPnP、Salutation、SLP 等。在这些服务发现体系中,服务的描述通过服务的名称或有限的属性集合来完成,缺乏必要的语义信息,而服务匹配也仅是基于接口或属性集来进行,不能推理服务的功能和特性,服务与服务之间不能相互识别。另一方面,在现有的服务发现体系中,也没有遵循共同的本体系统,容易造成信息的歧义性。在本论文中,结合语义Web 的相关研究,建立了普适计算环境中的基于语义的服务描述框架,提出了基于OWL(WEB 本体语言)的本体,用来描述服务和进行服务的语义匹配。利用OWL,从语义层次上来描述服务功能,揭示了服务之间的语义关系,同时,服务提供者与服务请求者遵循共同的本体系统来描述服务与需求,消除了信息的歧义性。论文也演示了如何利用已定义的本体系统来描述服务提供与服务请求。在本论文中,本体系统主要分为四个部分,包括空间本体、时间本体、个人信息本体及服务的本体。服务描述与服务匹配是普适环境中服务发现的两个主要方面,在已建立的用于服务描述的本体基础上,论文提出了服务发现的语义匹配算法。该匹配算法充分考虑了服务的语义信息,使用户与计算设备或设备与设备之间,可以在语义层次上进行交互,提高了服务匹配的准确性与智能程度,同时也为模糊匹配及服务组合打下了很好的基础。算法通过分类与比较服务提供者与服务请求者的类别、输入参数与输出参数来进行匹配。与当前的大多数服务发现协议的不同之处在于,算法揭示了服务类别、输入参数与输出参数的语义层次及语义关系,避免了简单的接口匹配和属性匹配。最后,基于Jena、JESS、OWLJessKB,实现了该服务匹配算法。更多还原

【Abstract】 Pervasive computing, sometimes called ubiquitous computing, is the third wave in computing. Locating a network service or a device on demand is a challenging task for pervasive computing. This paper provides an overview and comparison of several prominent service discovery mechanisms currently available, includes Jini, UPnP, Salutation, SLP and so on. Most of these systems use simple interface-based or attributed-based matching. They lack expressive languages, representations and tools that are good at representing a broad range of service descriptions and are good for reasoning about the functionalities and the capabilities of the services. Common ontology infrastructures are often missing from the existing service discovery architectures. In this paper we introduce a new approach that explores the use of Semantic Web language in building architecture for service discovery in pervasive computing environment. We propose an OWL (Web Ontology Language) based ontology for service description, and for supporting logic-based service matchmaking. By means of OWL we are able to define the “purpose”of a service by giving it a semantic meaning. Additionally, the ontology shows the semantic relationship of the services. We also point out how to describe a service provider and a service requester using the ontology. The ontology system was divided into several parts, includes space, time, personal information and service. Besides service description, Service matchmaking is another important problem in service discovery. We introduced a semantic matching algorithm according to the ontology. The algorithm takes the semantic meaning of service into account, enable interact between user and device or between device and device. It improves the veracity of service matching, and paves the way for fuzzy matching and service composition. The algorithm classifies and compares the request class, inputs and outputs to the advertisements class, inputs and outputs. The algorithm different from the most existing service discovery algorithm because the reasoner can reveal the semantic hierarchy of the classes, inputs and outputs, avoid the simple interface-based or attributed-based matching. At last, we implement the algorithm based on Jena, JESS and OWLJessKB.更多还原