Evaluation of Architectural Frameworks Supporting Contract-based Specification

The management and assurance of “systems of systems” (SoSs) are hampered by the difficulty of gaining confidence that a particular architecture of constituent systems will meet a global SoS-level requirement. Research suggests that recording explicit technical contracts at the boundaries between the SoS-constituent systems may help with verification of SoS-level properties, including non-functional characteristics. This report surveys approaches to the contract-based specification of SoS-constituent systems and focuses particularly on the description of such non-functional properties. The report reviews (i) current techniques for the representation of non-functional properties and (ii) current architectural description methods. The aims of the review are to determine the extent to which it would be possible to state and reason (with machine assistance) about non-functional properties and to assess the ability to incorporate contract descriptions at component boundaries in architectural descriptions. A direction for future work in the development of contract specification languages suitable for SoSs is proposed.