  Web services are widely used thanks to their features of universal
interoperability between software assets, platform independent and
loose-coupled. Web services composition is one of the most challenging topics
in service computing area. In this paper, an approach based on High Level
Petri-Net model as dynamic configuration schema of web services composition is
proposed to achieve self adaptation to run-time environment and self management
of composite web services. For composite service based applications, in
addition to functional requirements, quality of service properties should be
considered. This paper presents and proves some quality of service formulas in
context of web service composition. Based on this model and the quality of
service properties, a suitable configuration with optimal quality of service
can be selected in dynamic way to reach the goal of automatic service
composition. The correctness of the approach is proved by a simulation results
and corresponding analysis.
