Lexical Multicriteria-Based Quality Evaluation Model for Web Service Composition

Providing quality aware services to customers is an important problem in the composition of Web services. Often, the quality of services is considered from different aspects that we call criterions. Based on the criterions, customers compare and choose better (composed) Web services. Previous methods compare Web services by comparing their aggregate values, which are weighted sum of each quality (the WSum model). However, the WSum model is not proper to support qualitative preferences over criterions. Herein, we proposed a new evaluation model that lexically compares the qualities of Web services, which is called the Lexical model. In contrast with WSum model, our proposed Lexical model is more powerful in modeling users’ preferences both quantitatively and qualitatively. We will prove that it is in O(k ² ) for a WSum model to simulate the Lexical model, where k is the number of criterions. We may note that though the idea of Lexical models has been utilized in other areas, few researchers in the field of Web service composition noticed the way of using the Lexical model introduced here.