QoS probability distribution estimation for web services and service compositions

In this paper, we propose an approach to model the probability density function (PDF) of the QoS of a web service (QoWS) based on non-parametric statistical method. Mathematical formulas are designed to calculate the QoS distributions for service compositions (QoCS). Experiment has been done to show that the proposed QoWS distribution modeling approach is much more accurate than exiting methods. An accurate PDF estimation can be obtained for the QoCS if the PDF of the component QoWSs are modeled by the proposed method.