A QoS Query Language for User-Centric Web Service Selection

One of the prerequisites for the success of a QoS-based web service selection process is an accurately formulated QoS query. It is usually not an easy task for users to formulate an accurate query considering the complexity of many current QoS languages and users' lack of knowledge on realistic QoS values. It would be very helpful if the system can provide some assistance to users during the whole process. Nonetheless, not many research works put user support to the center of their system design. In this paper we want to tackle this issue by proposing a QoS query language which is expressive while not so complicated, together with a comprehensive user support mechanism to guide users through the query formulation process. A few unique features of the language include its time dimension, user-defined relaxation order which could be different from the preference order, and the support for the mixed fuzzy and range requirement. How to handle these new features is also discussed as case studies in the paper.