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Mathematical Problems in Engineering
Volume 2012, Article ID 783476, 21 pages
Research Article

A Cost-Effective Planning Graph Approach for Large-Scale Web Service Composition

1Institute of Information Management, National Chiao Tung University, Hsin-Chu 300, Taiwan
2Faculty of Computing and Engineering, Coventry University, Coventry CV1 5FB, UK

Received 16 November 2011; Revised 25 January 2012; Accepted 28 January 2012

Academic Editor: Jung-Fa Tsai

Copyright © 2012 Szu-Yin Lin et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Web Service Composition (WSC) problems can be considered as a service matching problem, which means that the output parameters of a Web service can be used as inputs of another one. However, when a very large number of Web services are deployed in the environment, the service composition has become sophisticated and complicated process. In this study, we proposed a novel cost-effective Web service composition mechanism. It utilizes planning graph based on backward search algorithm to find multiple feasible solutions and recommends a best composition solution according to the lowest service cost. In other words, the proposed approach is a goal-driven mechanism, which can recommend the approximate solutions, but it consumes fewer amounts of Web services and less nested levels of composite service. Finally, we implement a simulation platform to validate the proposed cost-effective planning graph mechanism in large-scale Web services environment. The simulation results show that our proposed algorithm based on the backward planning graph has reduced by 94% service cost in three different environments of service composition that is compared with other existing service composition approaches which are based on a forward planning graph.