An objective and automatic feedback model for QoS evaluation

Abstract

Quality of Service (QoS) is an important factor during service composition and recommendation. Since static QoS data cannot reflect the real-time performance of Web Service (WS), a mechanism is needed to collect the dynamic QoS data. Also, QoS query result is determined by the QoS data stored by service registry. Consequently, it is also necessary to use an efficient and accurate feedback method to calculate and send those dynamic QoS data to the service registry. In this paper, we propose a QoS feedback model based on objective QoS metrics using some simple statistical theories and a dynamic queue as a data pool to cache all runtime status. Moreover, error determination and sampling feedback have been taken into consideration so that service provider assigns less hardware resource and avoids disturbing feedback result from unfriendly exception. By carrying out experiments, it demonstrates that this feedback model evaluates the WS performance better than other common methods. This model provides QoS metrics that are easy to rank and sensitive to the status change.