Efficient Exploration of Cyber-Physical System Architectures Using Contracts and Subgraph Isomorphism

We present ContrArc, a methodology for the exploration of cyber-physical system architectures aiming to minimize a cost function while adhering to a set of heterogeneous constraints. We assume a system topology, defined as a graph, where components (nodes) are selected from an implementation library, and connections between components (edges) are drawn from a finite set of possible connection choices. ContrArc uses assume-guarantee contracts to formalize different viewpoints in the system requirements, such as timing and power consumption, as well as the interface of different components, and translate the exploration problem into a mixed integer linear programming problem. It then searches for efficient solutions by relying on contract decompositions and a method based on sub graph isomorphism to iteratively prune infeasible architectures out of the search space. Experiments on a reconfigurable production line and an aircraft power distribution network show up to two orders of magnitude acceleration in architectural exploration with respect to comparable approaches.