Virtual Environments are complex systems in that they involve the crucial concept of sharing. Users can share knowledge of each other’s current activities, environments, and actions. In this chapter, the authors discuss about interaction interoperability, intended to mean the ability of two or more users to cooperate despite the heterogeneity of their interfaces. To allow such interoperability, formal methods to formalize the knowledge and middleware solutions for sharing that knowledge are required. After introducing the state-of-the-art solutions and the open issues in the field, the authors describe a system for providing interaction interoperability among multi-user interfaces. Rather than focusing on the de-coupling of input devices from interaction techniques and from interaction tasks, this chapter suggests integrating interactive systems at higher level through an interface standardization. To achieve this aim, the authors propose: i) an architectural model able to handle differences in input devices and interaction tasks; ii) an agent-based middleware that provides basic components to integrate heterogeneous user interfaces. The chapter also presents a case study in which an agent-based middleware is used to support developers in the interconnection of monolithic applications.
Specification of an Automatic Manufacturing System: A Case Study in Using Integrated Formal Methods