A tag contract framework for modeling heterogeneous systems

Development of distributed systems can be supported effectively by a contract-based methodology as contracts can ensure interoperability of components and adherence to specifications. Such development can become very complex since distributed systems can consist of components which are heterogeneous in terms of computational and interactive model. Several frameworks, both operational and denotational, have been proposed to handle heterogeneity using a variety of approaches. However, the application of those frameworks to contract-based design has not yet been investigated. In this work, we adopt the operational mechanism of tag machines to represent heterogeneous systems and construct a full contract model. We introduce heterogeneous composition, refinement, dominance and compatibility between contracts, altogether enabling a formalized and rigorous design process for heterogeneous systems. Besides, we also develop a method to synthesize or refine the component models so that their composition satisfies a given contract.