An application of the mediator approach to services over the Web

This document is about mediation systems integrating services over the Web. First, we give an overview of the mediator approach. In section 3 we focus on integration of services over the Web. We explain which problems arise and we give principles to make the mediator approach applicable in this context. The first principle is a solution to semantic heterogeneity. It exploits results in standardization relative to business transactions. The second principle concerns the scalability of the mediator approach. It emphasizes two points: de-coupling of the various components and strong mediation. In the last section, we present an architecture of a mediation system integrating services, designed in the setting of the PICSEL 2 project. We illustrate with an application of e-commerce in the tourism domain.