Dirk A. van Beek

Hierarchical states in the Compositional Interchange Format

CIF is a language designed for two purposes, namely as a specification language for hybrid systems and as an interchange format for allowing model transformations between other languages for hybrid systems. To facilitate the top-down development of a hybrid system and also to be able to express models more succinctly in the CIF formalism, we need a mechanism for stepwise refinement. In this paper, we add the notion of hierarchy to a subset of the CIF language, which we call hCIF? . The semantic domain of the CIF formalism is a hybrid transition system, constructed using structural operational semantics. The goal of this paper is to present a semantics for hierarchy in such a way that only the SOS rules for atomic entities in hCIF? are redesigned in comparison to CIF . Furthermore, to be able to reuse existing tools like simulators of the CIF language, a procedure to eliminate hierarchy from an automaton is given.

Partially-Supervised plants: embedding control requirements in plant components

Supervisory control deals with automated synthesis of controllers based on models of the uncontrolled system and the control requirements. In this paper we share the lessons learned from synthesizing controllers for a patient support system of an MRI scanner regarding the specification of the control requirements. We learned that strictly following the philosophy of supervisory control, which partitions specifications in an uncontrolled plant and control requirements, may lead to unnecessarily complex specifications and duplication of information. In such cases, the specification can be substantially simplified by embedding part of the control requirements in so-called partially-supervised plants. To formalize the new concepts, we apply a recently developed process-theoretic approach to supervisory control. The new method for analysis of the models provides a better insight into their underlying behavior, which is demonstrated by revisiting the models of the industrial study.