Adaptation of Web Services Based on QoS Satisfaction

Requirements of Service Based Applications (SBAs) tend to change during the life cycle of the service. Therefore, adaptation and evolution of services become a necessity in order to provide the agreed Quality of Service (QoS) stated in a contract between the service provider and requestor. Recently, many adaptation methods have been proposed in the literature. However, there is no overall consensus in selecting the best strategy and the consequences of adaptation are usually neglected. In this paper, we propose an approach for service adaptation through defining a flexible service description using fuzzy parameters. This approach provides a compatibility mechanism that measures the aggregated satisfaction value of offered services to understand to what extent the quality changes are satisfiable according to the existing contract. According to the degree of satisfaction function we then propose our adaptation/evolution strategy.