QoS-Aware Composition of Web Services: An Evaluation of Selection Algorithms

A composition arranges available services resulting in a defined flow of executions. Before the composition is carried out, a discovery service identifies candidate services. Then, a selection process chooses the optimal candidates. This paper discusses how the selection can consider different Quality-of-Service (QoS) categories as selection criteria to select the most suitable candidates for the composition. If more than one category is used for optimisation, a multi-dimensional optimisation problem arises which results in an exponential computation effort for computing an optimal solution. We explain the problem and point out similarities to other combinatorial problems – the knapsack problem and the resource constraint project scheduling problem (RCPSP). Based on this discussion, we describe possible heuristics for these problems and evaluate their efficiency when used for web service candidate selection.

[1]  W.M.P. van der Aalst,et al.  Don't go with the flow: web services composition standards exposed , 2003 .

[2]  Anne H. H. Ngu,et al.  QoS-aware middleware for Web services composition , 2004, IEEE Transactions on Software Engineering.

[3]  Ching-Lai Hwang,et al.  Fuzzy Multiple Attribute Decision Making - Methods and Applications , 1992, Lecture Notes in Economics and Mathematical Systems.

[4]  Gero Mühl,et al.  QoS aggregation in Web service compositions , 2005, 2005 IEEE International Conference on e-Technology, e-Commerce and e-Service.

[5]  R. Weiner.  Lecture Notes in Economics and Mathematical Systems , 1985 .

[6]  Jianwen Su,et al.  E-services: a look behind the curtain , 2003, PODS.

[7]  Antonio Jorge Silva Cardoso,et al.  Quality of service and semantic composition of workflows , 2002 .

[8]  Daniel A. Menascé,et al.  QoS Issues in Web Services , 2002, IEEE Internet Comput..

[9]  Roy Grønmo,et al.  Model-Driven Methodology for Building QoS-Optimised Web Service Compositions , 2005, DAIS.

[10]  Peter P. Puschner,et al.  Computing Maximum Task Execution Times — A Graph-Based Approach , 2004, Real-Time Systems.

[11]  Peter Buneman,et al.  Semistructured data , 1997, PODS.

[12]  Christoph Bussler,et al.  Web Services, E-Business, and the Semantic Web , 2002, Lecture Notes in Computer Science.

[13]  Wil M. P. van der Aalst,et al.  Workflow Patterns , 2004, Distributed and Parallel Databases.

[14]  Gero Mühl,et al.  QoS aggregation for Web service composition using workflow patterns , 2004, Proceedings. Eighth IEEE International Enterprise Distributed Object Computing Conference, 2004. EDOC 2004..

[15]  Vladimir Tosic,et al.  WSOL - Web Service Offerings Language , 2002, WES.

[16]  Matthew MacDonald,et al.  Web Services Architecture , 2004 .

[17]  Gero Mühl,et al.  QoS aggregation for Web service composition using workflow patterns , 2004 .

[18]  William J. O'Brien,et al.  Resource-Constrained Project Scheduling: Past Work and New Directions 1 , 2001 .