TY  - CONF
ID  - www200989
UR  - http://www2009.eprints.org/89/
A1  - Alrifai, Mohammad
A1  - Risse, Thomas
Y1  - 2009/04//
N2  - The run-time binding of web services has been recently put forward in order to support rapid and dynamic web service compositions. With the growing number of alternative web services that provide the same functionality but differ in quality parameters, the service composition becomes a decision problem on which component services should be selected such that user?s end-to-end QoS requirements (e.g. availability, response time) and preferences (e.g. price) are satis?ed. Although very efficient, local selection strategy fails short in handling global QoS requirements. Solutions based on global optimization, on the other hand, can handle global constraints, but their poor performance renders them inappropriate for applications with dynamic and realtime requirements. In this paper we address this problem and propose a solution that combines global optimization with local selection techniques to bene?t from the advantages of both worlds. The proposed solution consists of two steps: ?rst, we use mixed integer programming (MIP) to ?nd the optimal decomposition of global QoS constraints into local constraints. Second, we use distributed local selection to ?nd the best web services that satisfy these local constraints. The results of experimental evaluation indicate that our approach signi?cantly outperforms existing solutions in terms of computation time while achieving close-tooptimal results.
TI  - Combining Global Optimization with Local Selection for Efficient QoS-aware Service Composition
SP  - 881
M2  - Madrid, Spain
AV  - public
EP  - 881
T2  - 18th International World Wide Web Conference
ER  -