Achieving high availability of web services based on a particle filtering approach

Abstract

Guaranteeing the high availability of Web services is a significant challenge due to the varying number of invocation requests the Web services have to handle at a time, as well as the dynamic nature of the Web. The issue becomes even more challenging for composite Web services in the sense that their availability is inevitably dependent on corresponding component Web services. Current Quality of Service (QoS)-based selection approaches assume that the QoS of Web services (such as availability) is readily accessible and services with better availability are selected in the composition. Unfortunately, how to provide real-time availability information of Web services is largely overlooked. In addition, the performance of these ap- proaches will raise questions when the pool of Web services to select from becomes large. In this paper, we tackle these problems by exploiting particle filtering-based techniques. In particular, we developed algorithms to accurately predict the availability of Web services and dynamically maintain a subset of Web services with higher availability ready to join service compositions. Web services can be always selected from this smaller space, thereby ensuring good performance in service compositions. Our implementation and experimental study demonstrate the feasibility and benefits of the proposed approach.