Research Of WEB Services Compositions And Multi-Agent Coordination System Technology

The recent evolution of internet technologies, mainly guided by the Extensible Markup Language (XML) and its related technologies, are extending the role of the World Wild WEB from information interaction to services interaction. This next wave of the internet era being driven by a concept named WEB services. The WEB services technology provides the underpinning to a new business opportunity, i.e., the possibility of providing value-added services through the composition of basic WEB Services compositions. The current WEB services technology provides the necessary communication model for enabling message exchange in the WEB services environment. However, communication interoperability is only part of the problem when considering the building of reliable WEB services compositions. Besides communication interoperability, the task of building of WEB services compositions requires mechanisms to deal with the inherent autonomy, and heterogeneity of WEB services. Unlike components of traditional business process, WEB services are typically provided by different organizations and they were designed not to be dependent of any collective computing entity. Thus, a good WEB services composition model cannot rely on WEB services providers to support dynamics composition facilities. In the current WEB services environments, it is very important to study how to build an flexible,opened WEB services compositions coordination system model since it is a key factor for WEB services based business applications to enhance their agility and popularization.This study is supported by two projects: the National Ministry of Science and Technology project "City Commerce Informationalizaion Typical Project-Community E-business System" and key project from Chinese National Science Foundation "the Research of Network Information Space Structural Model Oriented to Automatic Finding of Resources". According to the coordination requirement of WEB Services Compositions, We researched modeling theory and coordination method of WEB Services compositions from dynamical composition type and architecture model adapted to WEB services compositions.In this work, we present a framework, named CoWEB, which encompasses all the requirements just described, thus providing the necessary infrastructure for building reliable WEB services compositions. The CoWEB framework is composed of multilayered architecture, an task-based composition model and an XML-based composition language, The multilayered architecture of CoWEB separates the task of aggregating and homogenizing heterogeneous WEB services from the task of specifying coordination interaction patterns, thus providing a new general mechanism to deal with the complexity introduced by a large number of WEB services, The XML-based language, named WEB Services Composition Language(WSCL), is used for describing the coordination supporting and the content of WEB services, for defining the interaction rules of WEB services,and interaction patterns of compositions, WSCL is an extension of WSDL (WEB Services Description Language) thus it is adherent to the XML-based standard that enable WEB serviced technology. Still, we have developed formal definitions for reasoning on safe and correct execution of WEB services compositions built with the mechanisms provided by the CoWEB framework.Furthermore, it is very important for the successful deployment of multi-agent coordination to build effective cooperation and interaction model among the Agents. Negotiation and cooperation of agent also play an important role in coordination to WEB Services compositions in CoWEB architecture. By adopting a service-domain based multi-agent organization and KQML-based agent negotiation model, we could reconstruct CoWEB in organization-level and agent-level.At the end of this thesis, we designed and implemented a prototype named "CityCiS" system using CoWEB system model and methodology presented in this thesis.