The emergence of smart embedded devices in the user's environment creates new opportunities to build applications that better integrate real-time state of physical world and hence, provides user's value added services. To achieve this goal, service orientation is widely used. Service operations are sometimes embedded on hardware equipment. However, a single service satisfies an atomic only user need, so services need to be composed in order to satisfy user's requirements. We present an ontology based framework to facilitate a user driven composition of appropriate application. This framework allow user to specify their needs in a high level specification and the composition to be dynamically adjusted at runtime.