Herbert Praehofer

Bio: Herbert Praehofer is an academic researcher from Johannes Kepler University of Linz. The author has contributed to research in topics: DEVS & Systems theory. The author has an hindex of 11, co-authored 27 publications receiving 4105 citations.

Theory of modeling and simulation

Abstract: From the Publisher: Although twenty-five years have passed since the first edition of this classical text, the world has seen many advances in modeling and simulation, the need for a widely accepted framework and theoretical foundation is even more necessary today. Methods of modeling and simulation are fragmented across disciplines making it difficult to re-use ideas from other disciplines and work collaboratively in multidisciplinary teams. Model building and simulation has been made easier and faster by riding piggyback on advances in software and hardware. However, difficult and fundamental issues such as model credibility and interoperation have received less attention. These issues are now front and center under the impetus of the High Level Architecture (HLA) standard mandated by the U.S. DoD for all contractors and agencies. This book concentrates on integrating the continuous and discrete paradigms for modeling and simulation. A second major theme is that of distributed simulation and its potential to support the co-existence of multiple formalisms in multiple model components. Prominent throughout are the fundamental concepts of modular and hierarchical model composition. This edition presents a rigorous mathematical foundation for modeling and simulation. Also, it now provides a comprehensive framework for integrating the various simulation approaches employed in practice. Including such popular modeling methods as cellular automata, chaotic systems, hierarchical block diagrams, and Petri nets. A unifying concept, called the DEVS Bus, enables models, as expressed in their native formalisms, to be transparently mapped into the Discrete Event System Specification (DEVS). The book shows how to construct computationally efficient, object-oriented simulations of DEVS models on parallel and distributed environments. If you are doing integrative simulations, whether or not they are HLA compliant, this is the only book available to provide the foundation to understand, simplify and successfully accomplish your task. Herbert Praehofer is an Assistant Professor at the Johannes Kepler University in Linz, Austria. He has over 50 publications in international journals and conference proceedings on Modeling and Computer Simulation, Systems Theory, and Software Engineering. Tag Gon Kim is a Professor of Electrical Engineering at the Korea Advanced Institutes of Science and Technology (KAIST), Taejon, Korea. His research interests include discrete event systems modeling/simulation, computer/communication systems analysis, and object-oriented simulation engineering. He is a senior member of IEEE and SCS, and a member of ACM. * Provides a comprehensive framework for continuous and discrete event modeling and simulation * Explores the mathematical foundation of simulation modeling * Discusses system morphisms for model abstraction and simplification * Presents a new approach to discrete event simulation of continuous processes * Includes parallel and distributed simulation of discrete event models * Presentation of a concept to achieve simulator interoperability in the form of the DEVS-Bus * Complete coverage necessary for compliance with High Level Architecture (HLA) standards Bernard P Zeigler, is a Professor of Electrical & Computer Engineering at the University of Arizona and heads the Artificial Intelligence Simulation Research Group. He is the author of numerous books and publications, and he is the Editor-in-Chief of the Transactions of the Society for Computer Simulation International.

Theory of Modeling and Simulation: Integrating Discrete Event and Continuous Complex Dynamic Systems

Abstract: Part I: Basics. Introduction to Systems Modeling Concepts. Framework for Modeling and Simulation. Modeling Formalisms and Their Simulators. Introduction to Discrete Event System Specifications (DEVS). Hierarchy of System Specifications. Part II: Modeling Formalisms and Simulation Algorithms. Basic Formalisms: DEVS, DTSS, DESS. Basic Formalisms: Coupled Multicomponent Systems. Simulators for Basic Formalisms. Multiformalism Modeling and Simulation. DEVS-Based Extended Formalisms. Parallel and Distributed Discrete Event Simulation. Part III: System Morphisms: Abstraction, Representation, Approximation. Hierarchy of System Morphisms. Abstraction: Constructing Model Families. Verification, Validation, Approximate Morphisms: Living with Error. DEVS and DEVS-like Systems: Universality and Uniqueness. DEVS Representation of Systems. Part IV: System Design and Modeling and Simulation Environments. DEVS-Based Design Methodology. System Entity Structure/Model Base Framework. Collaboration and the Future.

System theoretic formalisms for combined discrete-continuous system simulation

Abstract: In this paper we present an approach to combined discrete-continuous modelling which can be used to model and simulate an intelligent multi-layer control architecture as can be found in high autonomy systems. The modelling approach is based on system theoretical concepts; the three system specification formalisms-differential equation, discrete time, and the discrete event system specification formalism-have been combined to facilitate multi-formalisms modelling. Simulation concepts are based on the abstract simulator concept for discrete event simulation developed by Zeigler. Similar simulation methods have been developed to simulate modular, hierarchical discrete time and differential equation specified systems as well as multi-formalism models. Included in the paper are several examples of multi-formalism models together with the simulation results from the STIMS environment-an implementation of the modelling and simulation concepts in Interlisp-D/LOOPS.

DEVS Framework for Modelling, Simulation, Analysis, and Design of Hybrid Systems

Abstract: We make the case that Discrete Event System Specification (DEVS) is a universal formalism for discrete event dynamical systems (DEDS). DEVS offers an expressive framework for modelling, design, analysis and simulation of autonomous and hybrid systems. We review some known features of DEVS and its extensions. We then focus on the use of DEVS to formulate and synthesize supervisory level controllers.

Visual modeling of DEVS-based multiformalism systems based on higraphs

Abstract: This paper presents a graphical modeling method and tool for DEVS model and DEVS-based combined discrete/continuous model specification. In DEVS-based modeling, atomic model behavior specification is organized around different phases which define a partition of the state space of the model. The phase transitions depict the qualitative state changes and naturally lend themselves to be represented by a state transition diagram. Our representation of these phase transitions is based on the higraph extension to conventional graph representations. In higraphs, the area of the diagram is used to represent set enclosure and exclusion and the Cartesian product which leads to remarkable reduction in the diagram's complexity. An interactive modeling tool based on the graphical representation developed is presented.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Differential Equations and Dynamical Systems

Abstract: Series Preface * Preface to the Third Edition * 1 Linear Systems * 2 Nonlinear Systems: Local Theory * 3 Nonlinear Systems: Global Theory * 4 Nonlinear Systems: Bifurcation Theory * References * Index

Pattern-oriented modeling of agent-based complex systems: lessons from ecology

Abstract: Agent-based complex systems are dynamic networks of many interacting agents; examples include ecosystems, financial markets, and cities. The search for general principles underlying the internal organization of such systems often uses bottom-up simulation models such as cellular automata and agent-based models. No general framework for designing, testing, and analyzing bottom-up models has yet been established, but recent advances in ecological modeling have come together in a general strategy we call pattern-oriented modeling. This strategy provides a unifying framework for decoding the internal organization of agent-based complex systems and may lead toward unifying algorithmic theories of the relation between adaptive behavior and system complexity.