Efficient web service composition via knapsack-variant algorithm

Abstract

Since the birth of web service composition, the minimization of the number of web services in the resulting composition while satisfying user requests has been a significant perspective of research. With the increase in the number of services released across the Internet, efficient algorithms for this research area are urgently required. In this paper, we present an efficient mechanism to solve the problem. For a given request, a service dependency graph is first generated with the relevant services selected from an external repository. Then, the searching process of the minimal composition over the graph is divided into several steps, and each search step is transformed into a dynamic knapsack problem by mapping services to items, the volume and cost of which are changeable, after which a knapsack-variant algorithm is applied to solve each problem in order. When the final search step has been completed, the minimal composition that satisfies the request can be obtained. Experiments on eight public datasets proposed for the Web Service Challenge 2008 demonstrate that the proposed mechanism outperforms the state-of-the-arts by generating solutions containing the same or a smaller number of services with much higher efficiency.