Thesis (Ph.D.) - Cairo University - Faculty of Graduate Studies for Statistical Research - Department of Information Systems and Technology

Service-Oriented Software Engineering (SOSE) plays a significant role in designing, developing, and maintaining software applications that will be developed by Web service (WS) technology. With the increasing complexity of users{u2019} requirements, WSs need to be combined together to fulfill them. The process of building new value-added services by integrating sets of existing WSs to satisfy users{u2019} requirements is called Web Service Composition (WSC). The selection of the best WS that fulfils the Functional Requirements (FRs) and optimizes the Quality of Service (QoS) requirements, such as response time, cost, reliability, etc., is a critical part of WSC, especially in a dynamic environment. WSs execute in a highly dynamic environment, as a result, the QoS of a WS is constantly evolving and this requires tracking of the global optimization over time to satisfy the users{u2019} requirements. In order to make a WSC adapt to such QoS changes of WSs, we propose a self-healing model for WSC. Self-healing is the automatic discovery and healing of the failure of a composite WS by itself due to QoS changes without interruption in the WSC and without any human intervention. To the best of our knowledge, almost all the existing self-healing models in this domain substitute the faulty WS with an equivalent one without paying attention to the WS selection processes to achieve the global optimization. They focus only on the WS substitution strategy

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