A QoS-Aware Web Service Client Framework for GUISET

A dissertation submitted by: Esau Laymon Mathonsi (Reg No: 20040445) To: Department of Computer Science, Faculty of Science and Agriculture, University of Zululand, Kwadlangezwa 3886, RSA Supervisor:Prof MO Adigun

Web Services have become one of promising technologies, and is getting widely adopted in business and also gradually deployed in real customer environment. The technology of Web Service is capable of providing a means to integrate different functional components over the Internet and enabling business entities to interact with one another through standard application program. As more and more Web Services become available on the service registry, selecting one Web Service among a group of Web Services which are offering similar functionality is a challenge. Quality of Service (QoS) is becoming an important criterion for differentiating Web services that offer similar functionality. However, the current SOA environment does not support QoS. This is because the discovery mechanism of the current SOA environment only considers the functionality (what the Web service does) of a Web service. There are many research efforts that attempted to address these issues in QoS-aware service discovery and selection but they still leave a lot to be desired. In this research work we propose an approach that utilises both the functionality and the QoS information of a Web service during service discovery and selection. This is realizable through our proposed GUISET QoS-aware Web service Selection Broker (G-Broker). The G-Broker allows service consumers to express their QoS requirements and select the most appropriate Web service for the service consumer. It also measures the QoS information of the selected Web service to avoid false QoS guarantees. It provides support for QoS negotiation between service consumer and providers and forces Service Level Agreement (SLA) creation. Lastly, it allows monitoring of the agreed QoS between clients and providers, and therefore, detecting any QoS violation. The G-Broker provides more satisfaction to consumers and also scales well as the number of Web services published in the service registry increases.

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