Modelling System of Systems Interface Contract Behaviour
This work addresses the problem of SoS evolution and integration for engineers, but it is incremental as it builds on existing Contract pattern methods.
The paper tackled the challenge of analyzing and maintaining global properties in System of Systems (SoS) engineering by enriching the Contract pattern with SysML and Object Constraint Language (OCL) and exploring interface automata for verifying contract compatibility, demonstrated through an audio/video content streaming case study.
A key challenge in System of Systems (SoS) engineering is the analysis and maintenance of global properties under SoS evolution, and the integration of new constituent elements. There is a need to model the constituent systems composing a SoS in order to allow the analysis of emergent behaviours at the SoS boundary. The Contract pattern allows the engineer to specify constrained behaviours to which constituent systems are required to conform in order to be a part of the SoS. However, the Contract pattern faces some limitations in terms of its accessibility and suitability for verifying contract compatibility. To address these deficiencies, we propose the enrichment of the Contract pattern, which hitherto has been defined using SysML and the COMPASS Modelling Language (CML), by utilising SysML and Object Constraint Language (OCL). In addition, we examine the potential of interface automata, a notation for improving loose coupling between interfaces of constituent systems defined according to the contract, as a means of enabling the verification of contract compatibility. The approach is demonstrated using a case study in audio/video content streaming.