Showing papers by "Bernard P. Zeigler published in 1994"
11 Dec 1994
TL;DR: The revision distinguishes between transition collisions and ordinary external events in the external transition function of DEVS models, which enables it to extend the modeling capability of the collisions.
Abstract: We present a revision of the hierarchical, modular Discrete Event System Specification (DEVS) modeling formalism. The revision distinguishes between transition collisions and ordinary external events in the external transition function of DEVS models. Such separation enables us to extend the modeling capability of the collisions. The revision also does away with the necessity for tie-breaking of simultaneously scheduled events, as embodied in the select function. The latter is replaced by a well-defined and consistent formal construct that allows all transitions to be simultaneously activated. The revision provides a modeler with both conceptual and parallel execution benefits.
287 citations
07 Dec 1994
TL;DR: This work presents a modeling methodology for representing variable structure systems, and describes an application of this methodology to the modeling and simulation of an adaptive computer architecture.
Abstract: Conventional modeling theory gives support only for representing model behavior, providing little aid for describing changes in model structure. Some models are better represented by changes in their structure. Instead of forcing this changes to be represented at the simple behavioral level, a strong theoretical support is needed to allow the representation of structural changes in a natural way. We present a modeling methodology for representing variable structure systems. Examples of such systems include adaptive computer architectures, ecological systems, fault tolerating computers. We describe an application of this methodology to the modeling and simulation of an adaptive computer architecture. >
13 citations
TL;DR: The overall goal of this paper is to develop a hierarchical diagnostic system that exploit knowledge of structure and behavior that is implemented and tested on several examples in the domain of robot-managed fluid-handling laboratory.
Abstract: Deep reasoning diagnostic procedures are model-based, inferring single or multiple faults from the knowledge of faulty behavior of component models and their causal structure. The overall goal of this paper is to develop a hierarchical diagnostic system that exploit knowledge of structure and behavior. To do this, we use a hierarchical architecture including local and global diagnosers. Such a diagnostic system for high autonomy systems has been implemented and tested on several examples in the domain of robot-managed fluid-handling laboratory.
12 citations
07 Mar 1994
TL;DR: This paper shows how GAs can effectively and efficiently optimize the performance of parameterized non-linear controllers, such as fuzzy net controllers in a multiprocessor simulation environment.
Abstract: As plant specifications become complicated, more robust controller design methodologies are needed. A genetic algorithm optimizer, which utilizes natural evolution strategies, offers a promising technology that supports optimization of the parameters of fuzzy logic and other parameterized non-linear controllers. This paper shows how GAs can effectively and efficiently optimize the performance of parameterized non-linear controllers, such as fuzzy net controllers in a multiprocessor simulation environment. Our results demonstrate the advantage of a Computer-Aided System Design technique for rapid prototyping of control systems. >
10 citations
16 May 1994
TL;DR: It is shown that causal dynamical systems with piecewise constant input and output segment spaces are DEVS-representable and closed under coupling, which justifies hierarchical, modular construction of both DEVS models and real-world counterpart systems.
Abstract: In this paper we address the question of the expressibility of discrete event specified systems (DEVS), i.e., we characterize the subclass of dynamical systems which can be homomorphically represented by DEVS models. We show that causal dynamical systems with piecewise constant input and output segment spaces are DEVS-representable. Moreover, DEVS-representable dynamical systems are closed under coupling, i.e., that a valid coupling of DEVS-representable dynamical systems is a DEVS-representable dynamical system. This justifies hierarchical, modular construction of both DEVS models and real-world (continuous or discrete) counterpart systems. Furthermore, we investigate a subclass of dynamical systems in detail, viz., discretely interacting continuous systems with internal dynamics specified by differential equations. This class is important in the rapidly developing field of hybrid autonomous systems control. As an application to CAST (computer-aided system technology), we show that this class is amenable to DEVS representation and therefore, also new forms of high performance parallel/distributed discrete event simulation.
8 citations
TL;DR: The DEVS-based intelligent control paradigm is applied to a space-adapted mixing system and the event-based approach is compared with conventional sequential control methods.
Abstract: This paper reviews a methodology for event-based intelligent control employing the DEVS (discrete event system specification) formalism In this control paradigm, the controller expects to receive confirming sensor responses to its control commands within definite time windows determined by its DEVS model of the system under control We apply the DEVS-based intelligent control paradigm to a space-adapted mixing system The event-based approach is compared with conventional sequential control methods
4 citations
16 May 1994
TL;DR: The next century will be characterized by ambitious attempts to design, construct, or manage ultralarge systems such as high bandwidth global communication networks, flexible manufacturing systems with high autonomy, and ecosystems distributed over large geographical regions.
Abstract: The next century will be characterized by ambitious attempts to design, construct, or manage ultralarge systems such as high bandwidth global communication networks, flexible manufacturing systems with high autonomy, and ecosystems distributed over large geographical regions Systems concepts and principles are needed to deal with such overwhelming complexity Fads continue to flash on the scene and fade just as fast The enduring advances have a fundamental robustness consistent with systems-based methodology
3 citations
07 Dec 1994
TL;DR: This paper establishes the adequacy of the preformal stages of the model represented by a verb phrase to serve as the basis for model construction and yet sufficiently "soft" to support knowledge acquisition during model construction.
Abstract: In investigating front end model development, an environment is described that allows for model construction through pruning a domain specific system entity structure. The preformal stages of the model will be represented by a verb phrase. This representation is sufficiently derailed to serve as the basis for model construction and yet sufficiently "soft" to support knowledge acquisition during model construction. This paper establishes the adequacy of this representation. >
1 citations