www.it-ebooks.info P1: OSO fm JWBS040-Nutaro August 30, 2010 14:35 Printer Name: Yet to Come ii www.it-ebooks.info P1: OSO fm JWBS040-Nutaro August 30, 2010 14:35 Printer Name: Yet to Come BUILDING SOFTWARE FOR SIMULATION i www.it-ebooks.info P1: OSO fm JWBS040-Nutaro August 30, 2010 14:35 Printer Name: Yet to Come ii www.it-ebooks.info P1: OSO fm JWBS040-Nutaro August 30, 2010 14:35 Printer Name: Yet to Come BUILDING SOFTWARE FOR SIMULATION Theory and Algorithms, with Applications in C++ JAMES J. NUTARO Oak Ridge National Laboratory A JOHN WILEY & SONS, INC., PUBLICATION iii www.it-ebooks.info P1: OSO fm JWBS040-Nutaro August 30, 2010 14:35 Printer Name: Yet to Come Copyright C  2011 by John Wiley & Sons, Inc. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada. 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ISBN 978-0-470-41469-9 (cloth) Printed in the United States of America 10987654321 iv www.it-ebooks.info P1: OSO fm JWBS040-Nutaro August 30, 2010 14:35 Printer Name: Yet to Come CONTENTS PREFACE ix 1 INTRODUCTION 1 1.1 Elements of a Software Architecture / 2 1.2 Systems Concepts as an Architectural Foundation / 4 1.3 Summary / 5 1.4 Organization of the Book / 6 2 FIRST EXAMPLE: SIMULATING A ROBOTIC TANK 7 2.1 Functional Modeling / 8 2.2 A Robotic Tank / 9 2.2.1 Equations of Motion / 11 2.2.2 Motors, Gearbox, and Tracks / 13 2.2.3 Complete Model of the Tank’s Continuous Dynamics / 17 2.2.4 The Computer / 18 2.2.5 Complete Model of the Tank / 22 2.3 Design of the Tank Simulator / 23 2.4 Experiments / 25 2.5 Summary / 30 3 DISCRETE-TIME SYSTEMS 32 3.1 Atomic Models / 33 v www.it-ebooks.info P1: OSO fm JWBS040-Nutaro August 30, 2010 14:35 Printer Name: Yet to Come vi CONTENTS 3.1.1 Trajectories / 33 3.1.2 The State Transition and Output Function / 35 3.1.3 Two Examples of Atomic, Discrete-Time Models / 39 3.1.4 Systems with Bags for Input and Output / 42 3.1.5 A Simulator for Atomic Models / 42 3.2 Network Models / 53 3.2.1 The Parts of a Network Model / 54 3.2.2 The Resultant of a Network Model / 55 3.2.3 An Example of a Network Model and Its Resultant / 56 3.2.4 Simulating the Resultant / 61 3.3 A Simulator for Discrete-Time Systems / 77 3.4 Mealy/Moore-Type Systems / 89 3.5 Cellular Automata / 91 3.6 Summary / 98 4 DISCRETE-EVENT SYSTEMS 100 4.1 Atomic Models / 101 4.1.1 Time and Trajectories / 101 4.1.2 The State Transition Function / 103 4.1.3 The Output Function / 105 4.1.4 Legitimate Systems / 106 4.1.5 An Example of an Atomic Model / 107 4.1.6 The Interrupt Handler in the Robotic Tank / 110 4.1.7 Systems with Bags for Input and Output / 114 4.1.8 A Simulator for Atomic Models / 114 4.1.9 Simulating the Interrupt Handler / 118 4.2 Network Models / 125 4.2.1 The Parts of a Network Model / 125 4.2.2 The Resultant of a Network Model / 126 4.2.3 An Example of a Network Model and Its Resultant / 128 4.2.4 Simulating the Resultant / 132 4.3 A Simulator for Discrete-Event Systems / 143 4.3.1 The Event Schedule / 144 4.3.2 The Bag / 153 4.3.3 The Simulation Engine / 157 4.4 The Computer in the Tank / 170 4.5 Cellular Automata Revisited / 176 4.6 Summary / 180 www.it-ebooks.info P1: OSO fm JWBS040-Nutaro August 30, 2010 14:35 Printer Name: Yet to Come CONTENTS vii 5 HYBRID SYSTEMS 182 5.1 An Elementary Hybrid System / 185 5.2 Networks of Continuous Systems / 186 5.3 Hybrid Models as Discrete-Event Systems / 187 5.4 Numerical Simulation of Hybrid Systems / 190 5.5 A Simulator for Hybrid Systems / 198 5.6 Interactive Simulation of the Robotic Tank / 211 5.6.1 Correcting the Dynamics of a Turn / 211 5.6.2 A Simplified Model of the Motor / 213 5.6.3 Updating the Display / 218 5.6.4 Implementing the Tank Physics / 219 5.7 Approximating Continuous Interaction Between Hybrid Models / 225 5.8 A Final Comment on Cellular Automata / 229 5.8.1 Differential Automata with Constant Derivatives / 229 5.8.2 Modeling Asynchronous Cellular Automata with Differential Automata / 230 5.8.3 A Homomorphism from Differential Automata to Asynchronous Cellular Automata / 232 5.9 Summary / 236 6 APPLICATIONS 237 6.1 Control Through a Packet-Switched Network / 237 6.1.1 Model of the Pendulum and Its PID Controller / 238 6.1.2 Integration with an Ethernet Simulator / 244 6.1.3 Experiments / 249 6.2 Frequency Regulation in an Electrical Power System / 255 6.2.1 Generation / 257 6.2.2 Transmission Network and Electrical Loads / 259 6.2.3 Frequency Monitoring and Load Actuation / 260 6.2.4 Software Implementation / 261 6.2.5 Experiments / 262 6.3 Summary / 269 7 THE FUTURE 271 7.1 Simulation Programming Languages / 271 7.2 Parallel Computing and Discrete-Event Simulation / 273 7.3 The Many Forms of Discrete Systems and Their Simulators / 276 7.4 Other Facets of Modeling and Simulation / 277 www.it-ebooks.info P1: OSO fm JWBS040-Nutaro August 30, 2010 14:35 Printer Name: Yet to Come viii CONTENTS APPENDIX A DESIGN AND TEST OF SIMULATIONS 279 A.1 Decomposing a Model / 280 A.1.1 Bottom-Up Testing / 280 A.1.2 Invariants and Assertions / 281 A.2 Input and Output Objects / 281 A.2.1 Simple Structures / 282 A.2.2 Unions / 282 A.2.3 Pointers and Hierarchies of Events / 284 A.2.4 Mixing Strategies with Model Wrappers / 286 A.3 Reducing Execution Time / 291 APPENDIX B PARALLEL DISCRETE EVENT SIMULATION 296 B.1 A Conservative Algorithm / 298 B.1.1 Lookahead / 300 B.1.2 The Algorithm / 303 B.2 Implementing the Algorithm with OpenMP / 304 B.2.1 Pragmas, Volatiles, and Locks / 304 B.2.2 Overview of the Simulator / 308 B.2.3 The LogicalProcess / 309 B.2.4 The MessageQ / 318 B.2.5 The ParSimulator / 321 B.3 Demonstration of Gustafson’s and Amdahl’s Laws / 325 APPENDIX C MATHEMATICAL TOPICS 331 C.1 System Homomorphisms / 331 C.2 Sinusoidal State-Steady Analysis / 333 REFERENCES 335 INDEX 345 www.it-ebooks.info [...]... models and the rules for their interconnection are otherwise invariant with their dynamics This permits models containing discrete and continuous components to be constructed within a single conceptual framework The consistent concept of a dynamic system—unvarying for components and networks, for models continuous and discrete—is also reflected in the facilities provided by the simulation engine for its... broader interpretation [152, 157] Building Software for Simulation: Theory and Algorithms, with Applications in C++, By James J Nutaro Copyright C 2011 John Wiley & Sons, Inc 7 www.it-ebooks.info P1: OSO c02 JWBS040-Nutaro 8 August 26, 2010 13:35 Printer Name: Yet to Come FIRST EXAMPLE: SIMULATING A ROBOTIC TANK reuse; programs for two experiments illustrate how they are applied and the benefit of doing... of Zeigler’s theory of modeling and simulation, introducing the theory s fundamental concepts and showing how to apply these to problems in engineering The original concept of the book was not so ambitious; its early stages more closely resembled a cookbook for building simulators, focusing almost exclusively on algorithms, examples of simulation programs, and guidelines for the object-oriented design... book retains much of this flavor, demonstrating each concept and algorithm with working code Unlike a cookbook, however, concepts and algorithms discussed in the text are not disembodied; their origins in the theory of modeling and simulation are made apparent, and this motivates and provides greater insight into their application Chapters 3, 4, and 5, are the centerpiece of the text I begin with discrete-time... stacks to obtain a packet, obtains the control information from that packet, and stores that information in a register where the interrupt handler that generates voltage signals can find it The interrupt handler runs periodically, and it has a higher priority than the thread that processes commands from the operator Therefore, time spent in the interrupt handler is not available to process commands from... queue; and the model’s phase, which is interrupted or operating It responds to two types of input: the interrupt indicator from the interrupt handler and packets from the network The interrupt indicator moves the system into its interrupted phase where it remains until a second interrupt indicator is received, and this moves the system back to its operating phase When the computer finishes processing a... transformations or by simply throwing out terms The best guides during this process are experience building simulation software, familiarity with the system being studied, and a clear understanding of the model’s intended use Functional models and their interconnections are the specification for the simulation software For this purpose, there are two types of functional model: atomic and network An atomic model... ending the turn, but using the equations designated for turning = false; ω changes instantaneously to zero and remains zero until the tank begins to turn again These differential equations describe how the tank moves in response to the propulsive force of the tracks The track forces Fl and Fr are inputs to this model, and we can take any function of the state variables—v, ω, θ , x, and y—as output For. .. by introducing continuous systems Numerical techniques for locating state events, scheduling time events, and solving differential equations are used to construct a special class of systems having internal dynamics that are continuous, but that produce and consume event trajectories and so are readily incorporated into a discrete-event model The simulation framework from Chapter 4 is expanded to include... same time that an input variable is changed, the event is executed first and then the corresponding variables are modified When the computer is not busy with its interrupt handler, it is processing commands from the operator Every command arrives as a UDP packet with 10 bytes: two floating-point numbers that specify the direction and duty ratio of the left and right motors, and 2 bytes of information that . Cataloging -in- Publication Data: Nutaro, James J. Building software for simulation: theory and algorithms with applications in C++ / James J. Nutaro p. cm. Includes bibliographical references and index. ISBN. its broader interpretation [152, 157]. Building Software for Simulation: Theory and Algorithms, with Applications in C++, By James J. Nutaro Copyright C  2011 John Wiley & Sons, Inc. 7 www.it-ebooks.info P1:. Come BUILDING SOFTWARE FOR SIMULATION Theory and Algorithms, with Applications in C++ JAMES J. NUTARO Oak Ridge National Laboratory A JOHN WILEY & SONS, INC., PUBLICATION iii www.it-ebooks.info P1: