QoS-based Approach for Dynamic Web Service Composition

Abstract

Web Services have become a standard for integration of systems in dis- tributed environments. By using a set of open interoperability standards, they allow computer-computer interaction, regardless the programming languages and operating systems used. The Semantic Web Services, by its turn, make use of ontologies to de- scribe their functionality in a more structural manner, allowing computers to reason about the information required and provided by them. Such a description also allows dynamic composition of several Web Services, when only one is not able to provide the desired functionality. There are scenarios, however, in which only the functional cor- rectness is not enough to fulfill the user requirements, and a minimum level of quality should be guaranteed by their providers. In this context, this work presents an ap- proach for dynamic Web Service composition that takes into account the composition overall quality. The proposed approach relies on a heuristics to efficiently perform the composition. In order to show the feasibility of the proposed approach, a Web Ser- vice composition application prototype was developed and experimented with public test sets, along with another approach that does not consider quality in the compo- sition process. The results have shown that the proposed approach in general finds compositions with more quality, within a reasonable processing time.