Abstract: Web service composition is often considered to be one of the most important and vital building blocks for Service Oriented Architecture. Toward that, we presented a new heuristic algorithm named HASC. The algorithm obtwins the solution through two steps which were traverse searching and regression. Both of the steps used heuristicmethod to select optimal Web services. In the process of traverse searching, the number of input parameters the Web service needed was considered as the heuristic function. In the process of regression, the heuristic function was the cardinality of the intersection generated by the output parameter set and the object ontology set. We evaluated the efficiency and effectiveness of HASC with two publicly available test sets-EEE05 and ICEI3E05. Compared with other similar algorithms, HASC can provide higher efficiency and shorter solution path for the requests.

Key words: Service oriented architecture, Web service composition, Heuristic search