An Multi-Agent Based Approach For Automated Semantic Web Services Composition

Composing the existing Web services according to corresponding semantic and logic to get value-added services is the focus of Web service research domain. Currently mainly problems of the Web service composition are the scalability of the system, the efficiency of transporting message and the difficulty of discovering the autonomic service. Furthermore, it has lower efficiency for the complex tasks composition. So this paper applied the current research of Web service composition, and the technologies of semantic Web, AI planning, situation calculus etc to research of automatic composition semantic Web service.The main research contents and research character in this paper are as follows:1. A composition semantic Web service model based on muti-agent(MACS) is proposed. The model is founded on the environment of distributed UDDI. Every UDDI is grouped by domain ontology, and each UDDI only accepts the Web service registration and query quest from a special domain. The model describes the Web services which already exist in the restricted domain UDDI and takes them as its ability. Besides this, it sets up a HA(Header Agent), which accepts the sub-agents' registration request about its ability, and at last composes Web service to resolve complex task by using of these abilities. Thus the solving of complex task in composition can be divided into two stages. At the first stage, the HA decompose the complex task into sub-tasks, and secondly send sub-tasks to corresponding SAWU(sub-agent with UDDI) for the second time planning.2. By evolving the existing Web service description model OWL-S, A model for describing the ability of sub-agent 0WL-S4SAWU( OWL-S for SAWU) is formed. Firstly, evolving the OWL with Web ontology language to design a restricted domain description language RuleDR, which can be used to describe the domain restricted rules that exist in the composition Web service. Then proposing a new Semantic Web service model called 0WL-S4SAWU by enriching OWL-S with domain restricted rules and the node ID which the 0WL-S4SAWU belongs to. 0WL-S4SAWU can be used as the abstract service for HA as well as supplying the SAWU to finish composition Web service automatically.3. The Web service composition planning algorithms of the HA and sub-Agent are implemented in a prototype system of MACS. HA do HTN planning by using 0WL-S4SAWU as operators. Sub-Agent composes Web services by taking the 0WL-S4SAWU as template, situation calculus as formal tools and the Golog as programming language.4. At last we have verified the service composition algorithm by experiment. The experiments fundamental net platform is JXTA.