Author(s): Liana Ţucăr, Paul Diac
Abstract: Abstract. In Web Service Composition, services or APIs from multiple and independent providers are combined to create new functionality. Web Service Challenges have formalized the problem at a series of events where the community competed with various solutions. The composition problem has been incrementally extended adding more expressiveness and since 2006 the semantic aspect was addressed by the use of ontologies for service parameter description. In this paper, we propose a polynomial-time algorithm based on graph search, that solves the 2008 challenge. The algorithm uses a heuristic to address the NP-Hard problem of optimizing the number of services selected. Experimental results show that our solution is a several times faster and generates shorter compositions on all evaluation tests compared with all winning solutions of the competition. Also it is up to 50 times faster and very close to generate shortest compositions on the tests, compared with the solution published in 2011, that generates optimal compositions.
Keywords: Service Composition; Semantic Web Services; Ontologies; Polynomial Time; Graph Search; Heuristic; Dynamic Scoring