Talcott, C., Arbab, F., & Yadav, M. (2015). Soft agents: exploring soft constraints to model robust adaptive distributed cyber-physical agent systems Software, Services and Systems: Essays Dedicated to Martin Wirsing on the Occasion of his Retirement from the Chair of Programming and Software Engineering (LNCS Vol. 8950, pp. 273-290).
We are interested in principles for designing and building open distributed systems consisting of multiple cyber-physical agents, specifically, where a coherent global view is unattainable and timely consensus is impossible. Such agents attempt to contribute to a system goal by making local decisions to sense and effect their environment based on local information. In this paper we propose a model, formalized in the Maude rewriting logic system, that allows experimenting with and reasoning about designs of such systems. Features of the model include communication via sharing of partially ordered knowledge, making explicit the physical state as well as the cyber perception of this state, and the use of a notion of soft constraints developed by Martin Wirsing and his team to specify agent behavior. The paper begins with a discussion of desiderata for such models and concludes with a small case study to illustrate the use of the modeling framework.