Efficient Symbolic Supervisory Synthesis and Guard Generation: Evaluating partitioning techniques for the state-space exploration

The supervisory control theory (SCT) is a model-based framework, which automatically synthesizes a supervisor that restricts a plant to be controlled based on specifications to be fulfilled. Two main problems, typically encountered in industrial applications, prevent SCT from having a major breakthrough. First, the supervisor which is synthesized automatically from the given plant and specification models might be incomprehensible to the users. To tackle this problem, an approach was recently presented to extract compact propositional formulae (guards) from the supervisor, represented symbolically by binary decision diagrams (BDD). These guards are then attached to the original models, which results in a modular and comprehensible representation of the supervisor. However, this approach, which computes the supervisor symbolically in the conjunctive way, might lead to another problem: the state-space explosion, because of the large number of intermediate BDD nodes during computation. To alleviate this problem, we introduce in this paper an alternative approach that is based on the disjunctive partitioning technique, including a set of selection heuristics. Then this approach is adapted to the guard generation procedure. Finally, the efficiency of the presented approach is demonstrated on a set of benchmark examples

Symbolic Supervisory Control of Timed Discrete Event Systems

With the increasing complexity of computer systems, it is crucial to have efficient design of correct and well-functioning hardware and software systems. To this end, it is often desired to control the behavior of systems to possess some desired properties. A specific class of systems is called discrete event systems (DES). DES deal with `discrete' quantities, e.g., ``number of robots in a manufacturing cell'', and their processes are driven by instantaneous `events', e.g., ``start of a machine''. In this thesis, the focus is on DES and an extension of such systems, which also considers the time points at which the events may occur, called \emph{timed DES (TDES)}. Real-time applications such as communication networks, manufacturing facilities, or the execution of a computer program, can be considered into TDES. Having a DES or TDES, with some given specifications, by utilizing a well-known mathematical framework, called supervisory control theory (SCT), it is possible to automatically generate a supervisor that restricts the system's behavior towards the specifications, only when it is necessary. Applying the SCT to large and complex systems, typically follows with some issues, concerning computational complexity and modeling aspects, which is tackled in this thesis. We model DES by extended finite automata (EFAs), state transition models that contain discrete-valued variables. TDES are modeled by an augmentation of EFAs, called timed EFAs (TEFAs), which contain a set of discrete-valued clocks. Based on EFAs or TEFAs, the supervisor can be symbolically computed, using binary decision diagrams (BDDs), data structures that could, in many cases, lead to smaller representation of the state space. For complex systems, the computed supervisor may consist of many states, causing representation and implementation difficulties. To tackle this, based on the states of the supervisor, we symbolically compute logical constraints that will be attached to the original models to restrict the system's behavior. Consequently, we present a framework, where given a set of EFAs or TEFAs, the supervisor is computed using BDDs, and represented in a modular manner based on the computed logical constraints. The framework has been developed, implemented, and applied to industrial case studies

Proceedings of the NASA Conference on Space Telerobotics, volume 2

These proceedings contain papers presented at the NASA Conference on Space Telerobotics held in Pasadena, January 31 to February 2, 1989. The theme of the Conference was man-machine collaboration in space. The Conference provided a forum for researchers and engineers to exchange ideas on the research and development required for application of telerobotics technology to the space systems planned for the 1990s and beyond. The Conference: (1) provided a view of current NASA telerobotic research and development; (2) stimulated technical exchange on man-machine systems, manipulator control, machine sensing, machine intelligence, concurrent computation, and system architectures; and (3) identified important unsolved problems of current interest which can be dealt with by future research

Computer Aided Verification

This open access two-volume set LNCS 11561 and 11562 constitutes the refereed proceedings of the 31st International Conference on Computer Aided Verification, CAV 2019, held in New York City, USA, in July 2019. The 52 full papers presented together with 13 tool papers and 2 case studies, were carefully reviewed and selected from 258 submissions. The papers were organized in the following topical sections: Part I: automata and timed systems; security and hyperproperties; synthesis; model checking; cyber-physical systems and machine learning; probabilistic systems, runtime techniques; dynamical, hybrid, and reactive systems; Part II: logics, decision procedures; and solvers; numerical programs; verification; distributed systems and networks; verification and invariants; and concurrency

Computer Aided Verification

This open access two-volume set LNCS 11561 and 11562 constitutes the refereed proceedings of the 31st International Conference on Computer Aided Verification, CAV 2019, held in New York City, USA, in July 2019. The 52 full papers presented together with 13 tool papers and 2 case studies, were carefully reviewed and selected from 258 submissions. The papers were organized in the following topical sections: Part I: automata and timed systems; security and hyperproperties; synthesis; model checking; cyber-physical systems and machine learning; probabilistic systems, runtime techniques; dynamical, hybrid, and reactive systems; Part II: logics, decision procedures; and solvers; numerical programs; verification; distributed systems and networks; verification and invariants; and concurrency

Tools and Algorithms for the Construction and Analysis of Systems

This book is Open Access under a CC BY licence. The LNCS 11427 and 11428 proceedings set constitutes the proceedings of the 25th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2019, which took place in Prague, Czech Republic, in April 2019, held as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2019. The total of 42 full and 8 short tool demo papers presented in these volumes was carefully reviewed and selected from 164 submissions. The papers are organized in topical sections as follows: Part I: SAT and SMT, SAT solving and theorem proving; verification and analysis; model checking; tool demo; and machine learning. Part II: concurrent and distributed systems; monitoring and runtime verification; hybrid and stochastic systems; synthesis; symbolic verification; and safety and fault-tolerant systems