Global and local QoS Guarantee in Web
Service Selection
Danilo Ardagna and Barbara Pernici
Abstract
In Service Oriented systems, complex applications can be composed from
a variety of functional equivalent Web services which may differ for
quality parameters. Under this scenario, applications are defined as
high level business processes and service composition can be
implemented dynamically by identifying the best set of services
available at run time. In this paper, we model the service composition
problem as a mixed integer linear problem where local constraints,
i.e., constraints for component Web services, and global constraints,
i.e., constraints for the whole application, can be specified. Our
approach proposes the formulation of the optimization problem as a
global optimization, not optimizing separately each possible execution
path as in other approaches. Experimental results demonstrate the
effectiveness of our approach.