Showing papers on "Modeling and simulation published in 2010"

Automatic Train Control System Development and Simulation for High-Speed Railways

Abstract: Research and development on high-speed railway systems and particularly its automatic control systems, are introduced. Numerical modeling of high-speed trains in the Chinese high-speed train system and its associate automatic control systems are described in detail. Moreover, modeling and simulation of train operation systems are analyzed and demonstrated.

Computational Electronics: Semiclassical and Quantum Device Modeling and Simulation

Abstract: Introduction to Computational Electronics Si-Based Nanoelectronics Heterostructure Devices in III-V or II-VI Technology Modeling of Nanoscale Devices The Content of This Book Introductory Concepts Crystal Structure Semiconductors Band Structure Preparation of Semiconductor Materials Effective Mass Density of States Electron Mobility Semiconductor Statistics Semiconductor Devices Semiclassical Transport Theory Approximations for the Distribution Function Boltzmann Transport Equation Relaxation-Time Approximation Rode's Iterative Method Scattering Mechanisms: Brief Description Implementation of the Rode Method for 6H-SiC Mobility Calculation The Drift-Diffusion Equations and Their Numerical Solution Drift-Diffusion Model Derivation Drift-Diffusion Application Example Hydrodynamic Modeling Introduction Extensions of the Drift-Diffusion Model Stratton's Approach Hydrodynamic (Balance, Blotekjaer) Equations Model The Need for Commercial Semiconductor Device Modeling Tools State-of-the-Art Commercial Packages The Advantages and Disadvantages of Hydrodynamic Models: Simulations of Different Generation FD SOI Devices Particle-Based Device Simulation Methods Direct Solution of Boltzmann Transport Equation: Monte Carlo Method Multi-Carrier Effects Device Simulations Coulomb Force Treatment within a Particle-Based Device Simulation Scheme Representative Simulation Results of Multiparticle and Discrete Impurity Effects Modeling Thermal Effects in Nano-Devices Some General Aspects of Heat Conduction Classical Heat Conduction in Solids Form of the Heat Source Term Modeling Heating Effects with Commercial Simulation Packages The ASU Particle-Based Approach to Lattice Heating in Nanoscale Devices Open Problems Quantum Corrections to Semiclassical Approaches One-Dimensional Quantum-Mechanical Space Quantization Quantum Corrections to Drift-Diffusion and Hydrodynamic Simulators The Effective Potential Approach in Conjunction with Particle-Based Simulations Description of Gate Current Models Used in Device Simulations Monte Carlo-k _ p-1D Schrodinger Solver for Modeling Transport in p-Channel Strained SiGe Devices Quantum Transport in Semiconductor Systems Tunneling General Notation Transfer Matrix Approach Landauer Formula and Usuki Method Far-From-Equilibrium Quantum Transport Mixed States and Distribution Function Irreversible Processes and MASTER Equations The Wigner Distribution Function Green's Functions Nonequilibrium Keldysh Green's Functions Low Field Transport in Strained-Si Inversion Layers NEGF in a Quasi-1D Formulation Quantum Transport in 1D-Resonant Tunneling Diodes Coherent High-Field Transport in 2D and 3D Conclusions Appendix A: Electronic Band Structure Calculation Appendix B: Poisson Equation Solvers Appendix C: Computational Electromagnetics Appendix D: Stationary and Time-Dependent Perturbation Theory Each chapter concludes with "Problems" and "References"

Modeling and simulation fundamentals : theoretical underpinnings and practical domains

Abstract: Preface. Contributors. 1 Introduction to Modeling and Simulation (Catherine M. Banks). M&S. M&S Characteristics and Descriptors. M&S Categories. Conclusion. References. 2 Statistical Concepts for Discrete Event Simulation (Roland R. Mielke). Probability. Simulation Basics. Input Data Modeling. Output Data Analysis. Conclusion. References. 3 Discrete-Event Simulation (Rafael Diaz and Joshua G. Behr). Queuing System Model Components. Simulation Methodology. DES Example. Hand Simulation Spreadsheet Implementation. Arena Simulation. Conclusion. References. 4 Modeling Continuous Systems (Wesley N. Colley). System Class. Modeling and Simulation (M&S) Strategy. Modeling Approach. Model Examples. Simulating Continuous Systems. Simulation Implementation. Conclusion. References. 5 Monte Carlo Simulation (John A. Sokolowski). The Monte Carlo Method. Sensitivity Analysis. Conclusion. References. 6 Systems Modeling: Analysis and Operations Research (Frederic D. McKenziei). System Model Types. Modeling Methodologies and Tools. Analysis of Modeling and Simulation (M&S). OR Methods. Conclusion. References. Further Readings. 7 Visualization (Yuzhong Shen). Computer Graphics Fundamentals. Visualization Software and Tools. Case Studies. Conclusion. References. 8 M&S Methodologies: A Systems Approach to the Social Sciences (Barry G. Silverman, Gnana K. Bharathy, Benjamin Nye, G. Jiyun Kim, Mark Roddy, and Mjumbe Poe). Simulating State and Substate Actors with CountrySim: Synthesizing Theories Across the Social Sciences. The CountrySim Application and Sociocultural Game Results. Conclusions and the Way Forward. References. 9 Modeling Human Behavior (Yiannis Papelis and Poornima Madhavan). Behavioral Modeling at the Physical Level. Behavioral Modeling at the Tactical and Strategic Level. Techniques for Human Behavior Modeling. Human Factors. Human Computer Interaction. Conclusion. References. 10 Verifi cation, Validation, and Accreditation (Mikel D. Petty). Motivation. Background Defi nitions. VV&A Defi nitions. V&V as Comparisons. Performing VV&A. V&V Methods. VV&A Case Studies. Conclusion. Acknowledgments. References. 11 An Introduction to Distributed Simulation (Gabriel A. Wainer and Khaldoon Al-Zoubi). Trends and Challenges of Distributed Simulation. A Brief History of Distributed Simulation. Synchronization Algorithms for Parallel and Distributed Simulation. Distributed Simulation Middleware. Conclusion. References. 12 Interoperability and Composability (Andreas Tolk). Defining Interoperability and Composability. Current Interoperability Standard Solutions. Engineering Methods Supporting Interoperation and Composition. Conclusion. References. Further Readings. Index.

Hybrid simulation models - When, Why, How?

Abstract: Agent-Based Modeling and Simulation (ABMS) and System Dynamics (SD) are two popular simulation paradigms. Despite their common goal, these simulation methods are rarely combined and there has been a very low amount of joint research in these fields. However, it seems to be advantageous to combine them to create more accurate hybrid models. In this research, the possible ways to combine these methods are studied. The authors have found five different situations where it will be useful to combine these methods. All of them have already been used in earlier studies, so modelers should use them as possible interfaces to combine the methodologies. By using hybrid simulation models it is possible to create more accurate and reliable Expert Systems (ES).

Nonsmooth Modeling and Simulation for Switched Circuits

Abstract: Nonsmooth Modeling and Simulation for Switched Circuits concerns the modeling and the numerical simulation of switched circuits with the nonsmooth dynamical systems (NSDS) approach, using piecewise-linear and multivalued models of electronic devices like diodes, transistors, switches. Numerous examples (ranging from introductory academic circuits to various types of power converters) are analyzed and many simulation results obtained with the INRIA open-source SICONOS software package are presented. Comparisons with SPICE and hybrid methods demonstrate the power of the NSDS approach. Nonsmooth Modeling and Simulation for Switched Circuits is intended to researchers and engineers in the field of circuits simulation and design, but may also attract applied mathematicians interested by the numerical analysis for nonsmooth dynamical systems, as well as researchers from Systems and Control.

Modeling and simulation of hydrostatic transmission system with energy regeneration using hydraulic accumulator

Abstract: A new hydraulic closed-loop hydrostatic transmission (HST) energy-saving system is proposed in this paper. The system improves the efficiency of the primary power source. Furthermore, the system is energy regenerative, highly efficient even under partial load conditions. It can work in either a flow or pressure coupling configuration, allowing it to avoid the disadvantages of each configuration. A hydraulic accumulator, the key component of the energy regenerative modality, can be decoupled from or coupled to the HST circuit to improve the efficiency of the system in low-speed, high-torque situations. The accumulator is used in a novel way to recover the kinetic energy without reversion of fluid flow. Both variable displacement hydraulic pump /motors are used when the system operates in the flow coupling configuration so as to enable it to meet the difficult requirements of some industrial and mobile applications. Modeling and a simulation were undertaken with regard to testing the primary energy sources in the two configurations and recovering the energy potential of the system. The results indicated that the low efficiency of traditional HSTs under partial load conditions can be improved by utilizing the pressure coupling configuration. The round-trip efficiency of the system in the energy recovery testing varied from 32% to 66% when the losses of the load were taken into account.

Modeling and Simulation of Lithium-Ion Batteries from Systems Engineering Perspective

Abstract: The lithium-ion battery is an ideal candidate for a wide variety of applications due to its high energy/power density and operating voltage. Some limitations of existing lithium-ion battery technology include underutilization, stress-induced material damage, capacity fade, and the potential for thermal runaway. This paper reviews efforts in the modeling and simulation of lithium-ion batteries and their use in the design of better batteries. Likely future directions in battery modeling and design including promising research opportunities are outlined.

Comparing time histories for validation of simulation models : Error measures and metrics

Abstract: Computer modeling and simulation are the cornerstones of product design and development in the automotive industry. Computer-aided engineering tools have improved to the extent that virtual testing may lead to significant reduction in prototype building and testing of vehicle designs. In order to make this a reality, we need to assess our confidence in the predictive capabilities of simulation models. As a first step in this direction, this paper deals with developing measures and a metric to compare time histories obtained from simulation model outputs and experimental tests. The focus of the work is on vehicle safety applications. We restrict attention to quantifying discrepancy between time histories as the latter constitute the predominant form of responses of interest in vehicle safety considerations. First, we evaluate popular measures used to quantify discrepancy between time histories in fields such as statistics, computational mechanics, signal processing, and data mining. Three independent error measures are proposed for vehicle safety applications, associated with three physically meaningful characteristics (phase, magnitude, and slope), which utilize norms, cross-correlation measures, and algorithms such as dynamic time warping to quantify discrepancies. A combined use of these three measures can serve as a metric that encapsulates the important aspects of time history comparison. It is also shown how these measures can be used in conjunction with ratings from subject matter experts to build regression-based validation metrics.

Building Software for Simulation: Theory and Algorithms, with Applications in C++

Abstract: A unique guide to the design and implementation of simulation softwareThis book offers a concise introduction to the art of building simulation software, collecting the most important concepts and algorithms in one place. Written for both individuals new to the field of modeling and simulation as well as experienced practitioners, this guide explains the design and implementation of simulation software used in the engineering of large systems while presenting the relevant mathematical elements, concept discussions, and code development.The book approaches the topic from the perspective of Zeigler's theory of modeling and simulation, introducing the theory's fundamental concepts and showing how to apply them to engineering problems. Readers will learn five necessary skills for building simulations of complicated systems:Working with fundamental abstractions for simulating dynamic systemsDeveloping basic simulation algorithms for continuous and discrete event modelsCombining continuous and discrete event simulations into a coherent wholeApplying strategies for testing a simulationUnderstanding the theoretical foundations of the modeling constructs and simulation algorithmsThe central chapters of the book introduce, explain, and demonstrate the elements of the theory that are most important for building simulation tools. They are bracketed by applications to robotics, control and communications, and electric power systems; these comprehensive examples clearly illustrate how the concepts and algorithms are put to use. Readers will explore the design of object-oriented simulation programs, simulation using multi-core processors, and the integration of simulators into larger software systems.The focus on software makes this book particularly useful for computer science and computer engineering courses in simulation that focus on building simulators. It is indispensable reading for undergraduate and graduate students studying modeling and simulation, as well as for practicing scientists and engineers involved in the development of simulation tools.

INVENT Modeling, Simulation, Analysis and Optimization

Abstract: In this paper, a new subsystem-based approach to solve aerospace vehicle energy management issues is described. The goal of this approach is to create an “Energy Optimized Aircraft” that will maximize energy utilization for broad capabilities while minimizing complexity. To support this goal, an advanced modeling and simulation ICD process is established. This process addresses several of the current challenges facing modeling and simulation of large integrated systems.

Mathematical Modelling and Computer Simulation of Activated Sludge Systems

Abstract: This international, comprehensive guide to modeling and simulation studies in activated sludge systems leads the reader through the entire modeling process – from building a mechanistic model to applying the model in practice. Mathematical Modelling and Computer Simulation of Activated Sludge Systems will: Mathematical Modelling and Computer Simulation of Activated Sludge Systems can be used as supplementary material for a graduate level wastewater engineering courses and is useful to a wide audience of researchers and practitioners. Experienced model users such as consultants, trained plant management staff may find the book useful as a reference and as a resource for self-guided study. ISBN: 9781843392385 (Print) ISBN: 9781780401683 (eBook)

Compact method for modeling and simulation of memristor devices: ion conductor chalcogenide-based memristor devices

Abstract: A compact model and simulation methodology for chalcogenide based memristor devices is proposed. From a microprocessor design view point, it is important to be able to simulate large numbers of devices within the integrated circuit architecture in order to speed up reliably the development process. Ideally, device models would accurately describe the characteristic device behavior and would be represented by single-valued equations without requiring the need for recursive or numerically intensive solutions. With this in mind, we have developed an empirical chalcogenide compact memristor model that accurately describes all regions of operations of memristor devices employing single-valued equations.

Modeling and simulation of nuclear fuel materials

Abstract: We review the state of modeling and simulation of nuclear fuels with emphasis on the most widely used nuclear fuel, UO2. The hierarchical scheme presented represents a science-based approach to modeling nuclear fuels by progressively passing information in several stages from electronic structure calculations to continuum level simulations. Such an approach is essential to overcome the challenges posed by radioactive materials handling, experimental limitations in modeling extreme conditions and accident scenarios, and the small time and distance scales of fundamental processes. When used in conjunction with experimental validation, this multiscale modeling scheme can provide valuable guidance to development of fuel for advanced reactors to meet rising global energy demand.

Meta-Languages and Semantics for Equation-Based Modeling and Simulation

Abstract: Performing computational experiments on mathematical models instead of building and testing physical prototypes can drastically reduce the develop cost for complex systems such as automobiles, airc ...

Enzymatic numerical P systems - a new class of membrane computing systems

Abstract: A P system represents a distributed and parallel computing model in which basic data structures are multi-sets, strings or numerical variables. Numerical P systems have been introduced for possible applications in economics. A simulator for numerical P systems (SNUPS) has been designed, implemented and made available to the scientific community by the authors of this paper. SNUPS allows the development of a wide range of applications, from modeling and simulation of ordinary differential equations, to design and simulation of computational blocks for cognitive architectures and of membrane controllers for autonomous mobile robots. This paper introduces a new class of membrane computing systems, that of enzymatic numerical P systems, in which enzyme-like variables allow the existence of more than one production function in each membrane. The way this new type of deterministic numerical P systems works and the corresponding implementation in SNUPS are detailed, together with an illustrative example.

Modeling, Simulation, and Optimization of Supply Chains: A Continuous Approach

Abstract: This book offers a state-of-the-art introduction to the mathematical theory of supply chain networks, focusing on supply chain networks described by partial differential equations (PDEs). The authors discuss modeling of complex supply networks as well as their mathematical theory; explore modeling, simulation, and optimization of some of the discussed models; and present analytical and numerical results on optimization problems. Real-world examples are given to demonstrate the applicability of the presented approaches. Audience: Graduate students and researchers who are interested in the theory of supply chain networks described by PDEs will find this book useful. It can also be used in advanced graduate-level courses on modeling of physical phenomena, as well as introductory courses on supply chain theory. Contents: Preface; Chapter 1: Introduction; Chapter 2: Mathematical Preliminaries Chapter 3: Basic Queueing Models; Chapter 4: Models Based on Ordinary Differential Equations; Chapter 5: Models Based on Partial Differential Equations; Chapter 6: Continuum-Discrete Models; Chapter 7: Control and Optimization Problem for Networks; Chapter 8: Computational Results; Bibliography; Index

Modeling, Simulation, and Experimental Validation of a Generation System for Medium-Voltage DC Integrated Power Systems

Abstract: In this paper, a demonstrative technological implementation of a shipboard 2.15-MVA generation system is described, along with its modeling, numeric simulation, and some factory tests. The system, named Naval Package (NP), is part of a demonstrative program commissioned by Italian Navy for preliminary evaluations of medium-voltage dc supply technologies aimed at equipping its future vessels. The NP is made by a dual-star alternator, whose two stator three-phase windings feed two full-bridge diode rectifiers, respectively. The alternator (rated speed 6300 r/min) is designed to be moved by a 22 000-r/min gas turbine through a gearbox. This paper will present NP innovative issues, with reference to design solutions, operative requirements, dynamic modeling under normal and faulty conditions, and some factory tests.

Modeling and Simulation in Scilab

Abstract: One of the fundamental problems in many areas of science and engineering is the problem of modeling and simulation. Scilab provides a large array of tools for developing and simulating models of several types. For several of these tools it is possible to use them with abbreviated commands and default values of some parameters. However, to know how to choose the appropriate tools and how to get the kind of answers desired, it is often necessary to know something about how the algorithms are set up and what to do if there are difficulties.

Consistency Checking of Mechatronic Design Models

Abstract: During all phases of the design process there is a need to build models. Hierarchical models are very important tools for complex activities such as engineering design. In engineering of high performance products, mathematical modeling and simulation, i.e. experimenting with computer-based models, is an increasingly important technique for solving problems, evaluating solutions and making decisions. However, large design models may contain thousands of model elements. Designers easily get overwhelmed maintaining the correctness of such design models over time. Not only is it hard to detect new errors when the model changes but it is also hard to keep track of known errors. In the software engineering community this problem is known as a consistency problem and errors in models are known as inconsistencies. This paper presents an approach for consistency checking of mechatronic design models.

Cyber-Enabled Simulations in Nanoscale Science and Engineering

Abstract: The article describes recent progress in atomic and molecular level modeling and simulation of nanoscale materials and processes, as well as efforts by the US National Science Foundation's Network for Computational Nanotechnology (NCN) to cyber-enable such simulation tools together with instructional materials and research seminars. We believe that making advanced simulation tools widely and easily available to the research and education community will significantly enhance the impact of modeling and simulation on nanoscience and nanotechnology To materialize this vision, NCN established nanoHUB.org, a next-generation Web portal or science gateway that lets users run live, interactive simulations, explore data, and learn-all though a simple Web browser without installing any software or providing compute cycles.

Simulation of service-oriented and distributed manufacturing systems

Abstract: In this paper modeling and simulation is discussed in the context of distributed manufacturing systems (DiMS). The DiMS concept aims towards efficient and innovative collaboration that integrates design and development activities of manufacturing systems. A DiMS, described formally as a digital manufacturing system, is a competent basis for the modeling and simulation of manufacturing systems. The activities of the simulation model are described on the basis of a service-oriented approach in which content of the services is completely known. Micro, meso, and macro manufacturing levels are applied to the modeling and simulation. By means of these levels the hierarchy of the communication of the services is illustrated. An example is described in which modeling and simulation is used to proceed from ideas to efficiently operated manufacturing systems.

Level set approach to anisotropic wet etching of silicon.

Abstract: In this paper a methodology for the three dimensional (3D) modeling and simulation of the profile evolution during anisotropic wet etching of silicon based on the level set method is presented. Etching rate anisotropy in silicon is modeled taking into account full silicon symmetry properties, by means of the interpolation technique using experimentally obtained values for the etching rates along thirteen principal and high index directions in KOH solutions. The resulting level set equations are solved using an open source implementation of the sparse field method (ITK library, developed in medical image processing community), extended for the case of non-convex Hamiltonians. Simulation results for some interesting initial 3D shapes, as well as some more practical examples illustrating anisotropic etching simulation in the presence of masks (simple square aperture mask, convex corner undercutting and convex corner compensation, formation of suspended structures) are shown also. The obtained results show that level set method can be used as an effective tool for wet etching process modeling, and that is a viable alternative to the Cellular Automata method which now prevails in the simulations of the wet etching process.

Current status and future direction in the numerical modeling and simulation of machining processes: a critical literature review

Abstract: This paper presents a literature review on modeling and simulation of the metal cutting process, with special consideration to difficult-to-cut materials. The critical issues in the modeling of the cutting process are presented and investigated, which include the identification and formulation of the material constitutive equation, as well as the models that describe the tribological and thermal interactions at the tool-chip interface. The available approaches for generating constitutive data are critically examined, and their advantages, capabilities and limitations are discussed. The formulation of the constitutive equation significantly affects the accuracy of the finite element (FE) simulation. The evaluation criteria proposed recently by the authors to assess the goodness of different constitutive relationships for the machining process are presented. It is shown that more accurate simulation can be obtained when using a pressure-dependent friction model, compared to that with uniform coefficients. S...

CNT-MOSFET modeling based on artificial neural network: Application to simulation of nanoscale circuits

Abstract: In this paper, we have applied artificial neural network (ANN) for modeling and simulation of carbon nanotube metal–oxide-semiconductor field-effect transistors (CNT-MOSFETs). The simulation is based on ANN model which reduces the computational time while keeping the accuracy of physics-based model like non-equilibrium Green’s function (NEGF) formalism. Finally, the proposed ANN model is imported into HSPICE software as a subcircuit. Results show that the ANN model is suitable to be incorporated into Spice-like tools for nanoscale circuits simulation.