Bi-Level Selection Model for Web Services Search

Abstract

Service registries and web service engines are the main approaches for discovering web services. Current service directories are mainly based on Universal Description, Discovery and Integration (UDDI), which is an industry standard for service registries, developed to solve the web service search problem. However, UDDI offers limited search functionalities which may return a huge number of irrelevant services. Another critical challenge in web service search and composition is the selection of web services, to be executed or to be composed, from the pool of matching services. Most of the current service selection proposals apply a weighted sum model (WSM) as an evaluation method for selection of services with the same functionality. In this paper, we propose a Bi-level service selection approach that selects the most appropriate web services from the pool of matching services that considers both the functional and non-functional requirements for service selection. The functional requirements are provided by the user as a set of input parameters provided for and output parameters desired from the web service. The user also provides a set of desired QoS values and the order of their preference for selection. The experimental results demonstrate the efficiency of service search in our bi-level model and the variety of user queries supported.