Date Added: May 2012
Web Service Composition (WSC) assumes that the Service-Level Agreements (SLAs) the service provider commits remain steady throughout the composition's execution. However, WSC often operates in environment where the QoS of Web services changes relatively frequently. In this situation, the runtime QoS of real world WSCs will not always be equal to the QoS parameter settings specified by its SLA. Unfortunately, most existing researches still employ a static prediction strategy in predicting the QoS of WSC, where the QoS parameters published by SLA (or service providers) are simply trusted and used as model input for calculation of dynamic QoS metrics, and no runtime fluctuations of QoS parameters are considered.