The development of the web technologies and the increasing of available services have introduced the issue of the selection of the most appropriate service among a set of candidate web services. First of all, the services offering a given functionality are discovered. Then, the service section process assists users in choosing the services that better meets their preferences. These preferences are generally, expressed as potentially objective functions often conflicting. Most of existing works trying to select the best web services are based either on a single evaluation criterion or, at best, on the use of an aggregation function like weighted sum of several quantitative evaluation criteria, or the use of the Pareto optimality notion. The work presented here addresses these shortcomings by introducing a new optimality notion based on two tests: (i) concordance and (ii) discordance tests. It presents an efficient algorithm to select only the best services using the introduced optimality notion. Moreover, the proposed algorithm exhibits encouraging results as supported by a series of experiments.
Web services are self contained, self-describing modularapplications that can be published, located, and invoked acrossthe Web. Service Oriented Computing (SOC) uses services tosupport low-cost, flexible software. The underlying services areloosely coupled, thus allowing rapid change of such systems.The Web services architecture is defined by W3C (The WorldWide Web Consortium) in order to determinate a common setof concepts and relationships that allow different implemen-tations working together. In this way, they provide asatisfactory solution to the interoperability problem betweenheterogeneous components. At the same time, however, theygenerate several problems such as the delivered quality ofservice to users.
Moreover, although a framework for defining the functionalinterfaces of Web services has been established, non-functionalproperties remain under-development. In that perspective, oneimportant issue related to the selection of the most appropriateweb services among a set of different possible availableservices must be overcomed.
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