Showing papers on "Modeling and simulation published in 2004"
TL;DR: In this article, a new approach to the modeling and simulation of flexible microstructures under the effect of squeeze-film damping is presented, which utilizes the compressible Reynolds equation coupled with the equation governing the plate deflection.
Abstract: We present a new approach to the modeling and simulation of flexible microstructures under the effect of squeeze-film damping. Our approach utilizes the compressible Reynolds equation coupled with the equation governing the plate deflection. The model accounts for the electrostatic forcing of the capacitor airgap, the restoring force of the microplate and the applied in-plane loads. It also accounts for the slip condition of the flow at very low pressures. Perturbation methods are used to derive an analytical expression for the pressure distribution in terms of the structural mode shapes. This expression is substituted into the plate equation, which is solved in turn using a finite-element method for the structural mode shapes, the pressure distributions, the natural frequencies and the quality factors. We apply the new approach to a variety of rectangular and circular plates and present the final expressions for the pressure distributions and quality factors. Our theoretically calculated quality factors are in excellent agreement with available experimental data and hence our methodology can be used to simulate accurately the dynamics of flexible microstructures and predict their quality factors under a wide range of gas pressures. Because the pressure distribution is related analytically to the deflection, the dimension of the coupled structural-fluidic problem and hence the number of global variables needed to describe the dynamics of the system is reduced considerably. Consequently, the new approach can be significant to the development of computationally efficient CAD tools for microelectromechanical systems.
247 citations
Book•
01 Jan 2004
TL;DR: In this paper, the authors present a simulation of one-dimensional Steady-State Models of Solid Fuels Equipment and Processes using Bubbling Fluidized-Bed Combustion and Gasification Models.
Abstract: Basic Remarks on Modeling and Simulation Solid Fuels Equipment and Processes Basic Calculations Zero-Dimensional Models Introduction to One-Dimensional Steady-State Models Moving-Bed Combustion and Gasification Model Chemical Reactions Heterogeneous Reactions Drying and Devolatilization Auxiliary Equations and Basic Calculations Moving-Bed Simulation Programs and Results Bubbling Fluidized-Bed Combustion and Gasification Model Fluidization Dynamics Auxiliary Parameters Related to Fluidized-Bed Processes Bubbling Fluidized-Bed Simulation Program and Results Circulating Fluidized-Bed Combustion and Gasification Model Circulating Fluidized-Bed Simulation Program and Results Appendices Index
246 citations
01 Sep 2004
TL;DR: There is the biggest challenge facing modeling and Simulation analysts today: that of convincing management to sponsor modeling and simulation projects instead of, or in addition to, more commonly used manufacturing system design and improvement methods such as lean manufacturing and six sigma.
Abstract: Even though we have moved beyond the Industrial Age and into the Information Age, manufacturing remains an important part of the global economy. There is a need for the pervasive use of modeling and simulation for decision support in current and future manufacturing systems, and several challenges need to be addressed by the simulation community to realize this vision. First, an order of magnitude reduction in problem-solving cycles is needed. The second grand challenge is the development of real-time, simulation-based problem-solving capability. The third grand challenge is the need for true plug-and-play interoperability of simulations and supporting software. Finally, there is the biggest challenge facing modeling and simulation analysts today: that of convincing management to sponsor modeling and simulation projects instead of, or in addition to, more commonly used manufacturing system design and improvement methods such as lean manufacturing and six sigma.
242 citations
239 citations
Journal Article•
TL;DR: The basic idea, concepts, and framework of management and control for complex systems based on parallel systems methods are presented and the relationship of control systems and parallel systems is discussed.
Abstract: The basic idea, concepts, and framework of management and control for complex systems based on parallel systems methods are presented. The relationship of control systems and parallel systems is discussed. Parallel system methods are a further development and natural extension of control systems and computer-based modeling and simulation, resulting from new and recent advances in computing structure, algorithms, and technology. Parallel system methods might provide effective tools for control and management of complex systems that can not be modeled precisely or experimented repeatedly.
208 citations
01 Sep 2004
TL;DR: An overview of the CAMPaM field is presented and it is shown how transformations assume a central place and are explicitly modeled themselves by graph grammars.
Abstract: Modeling and simulation are quickly becoming the primary enablers for complex system design. They allow the representation of intricate knowledge at various levels of abstraction and allow automated analysis as well as synthesis. The heterogeneity of the design process, as much as of the system itself, however, requires a manifold of formalisms tailored to the specific task at hand. Efficient design approaches aim to combine different models of a system under study and maximally use the knowledge captured in them. Computer Automated Multi-Paradigm Modeling (CAMPaM) is the emerging field that addresses the issues involved and formulates a domain-independent framework along three dimensions: (1) multiple levels of abstraction, (2) multiformalism modeling, and (3) meta-modeling. This article presents an overview of the CAMPaM field and shows how transformations assume a central place. These transformation are, in turn, explicitly modeled themselves by graph grammars.
164 citations
TL;DR: By using the proposed method, the time step for analysis of the system can be increased and the required computation time and computer memory for complex systems can be reduced considerably.
Abstract: This paper presents a modular approach for the modeling and simulation of multiconverter DC power electronic systems based on the generalized state-space averaging method. These systems may consist of many individual converters connected together to form large and complex systems. In addition to simplifying the analysis procedure, by using the proposed method, the time step for analysis of the system can be increased. Therefore, the required computation time and computer memory for complex systems can be reduced considerably. In this paper, after introducing the proposed approach, results of applying the method to a representative system are presented.
163 citations
TL;DR: An initial review of the various modeling approaches based on Petri net found in the literature, and of the biological systems that have been successfully modeled with these approaches.
Abstract: Petri nets are a discrete event simulation approach developed for system representation, in particular for their concurrency and synchronization properties. Various extensions to the original theory of Petri nets have been used for modeling molecular biology systems and metabolic networks. These extensions are stochastic, colored, hybrid and functional. This paper carries out an initial review of the various modeling approaches based on Petri net found in the literature, and of the biological systems that have been successfully modeled with these approaches. Moreover, the modeling goals and possibilities of qualitative analysis and system simulation of each approach are discussed.
155 citations
TL;DR: A novel compact derivation is provided for the stochastic rate constant that forms the basis of the popular Gillespie algorithm and is argued that some of the arguments put forward are ignoring subtle differences and similarities that are important for answering the question in which conceptual framework one should investigate intracellular dynamics.
Abstract: Systems biology is a reemerging paradigm which, among other things, focuses on mathematical modeling and simulation of biochemical reaction networks in intracellular processes. For most simulation tools and publications, they are usually characterized by either preferring stochastic simulation or rate equation models. The use of stochastic simulation is occasionally accompanied with arguments against rate equations. Motivated by these arguments, we discuss in this paper the relationship between these two forms of representation. Toward this end, we provide a novel compact derivation for the stochastic rate constant that forms the basis of the popular Gillespie algorithm. Comparing the mathematical basis of the two popular conceptual frameworks of generalized mass action models and the chemical master equation, we argue that some of the arguments that have been put forward are ignoring subtle differences and similarities that are important for answering the question in which conceptual framework one should investigate intracellular dynamics.
141 citations
Journal Article•
TL;DR: Major modeling and simulation V&V challenges are identified and how they are being addressed and how to address them are indicated.
Abstract: Modeling and simulation play increasingly important roles in modern life. They contribute to our understanding of how things function and are essential to the effective and efficient design, evaluation, and operation of new products and systems. Modeling and simulation results provide vital information for decisions and actions in many areas of business and government. Verification and validation (V&V) are processes that help to ensure that models and simulations are correct and reliable. Although significant advances in V&V have occurred in the past 15 years, significant challenges remain that impede the full potential of modeling and simulation made possible by advances in computers and software. This article identifies major modeling and simulation V&V challenges and indicates how they are being addressed.
119 citations
TL;DR: A simulation model for CCD and CMOS imager-based luminescence detection systems is developed and signal processing algorithms are applied to the image to enhance detection reliability and hence increase the overall system throughput.
01 Jan 2004
TL;DR: This paper presents the basic idea, concepts, and methods of computational experiments, and discusses issues related to computer simulation, observation and explanation based emergence.
Abstract: This paper presents the basic idea, concepts, and methods of computational experiments, and discusses issues related to computer simulation, observation and explanation based emergence. Computational experiments are a natural extension and further development of modeling and simulation, resulting from recent and new advances of computing structure, algorithms, and technology, and provide effective tools for experimenting with complex systems, analyzing their behaviors and evaluating their decision-making processes.
TL;DR: This paper focuses on the dynamics of a multiple manipulator space free-flying robot (SFFR) with rigid links and issues relevant to the development of appropriate control algorithms.
Abstract: This paper focuses on the dynamics of a multiple manipulator space free-flying robot (SFFR) with rigid links and issues relevant to the development of appropriate control algorithms. To develop an explicit dynamics model of such complex systems, the Lagrangian formulation is applied. First, the system kinetic energy is derived based on a developed kinematics approach. Then, through vigorous mathematical analyses, three formats are obtained which describe the contribution of each term of kinetic energy to the equations of motion. Next, explicit derivations of a system's mass matrix, and of the vectors of non-linear velocity terms and generalized forces are introduced for the first time. The obtained dynamics model is very useful for dynamics analyses, design and development of control algorithms for such complex systems. The explicit SFFR dynamics can be implemented either numerically or symbolically. Following the latter approach, the developed symbolic code for dynamics modeling, i.e. SPACEMAPLE, and its...
01 Jan 2004
TL;DR: Principles of Object-Oriented Modeling and Simulation with Modelica 2.1 introduces the latest methods of object-oriented component-based system modeling and simulation, and provides a tutorial and reference for the latest version of Modelica complete with a comprehensive overview of application model libraries from many domains.
Abstract: A timely introduction to the latest modeling and simulation techniques Object-oriented modeling is a fast-growing area of modeling and simulation that provides a structured, computer-supported way of doing mathematical and equation-based modeling. Modelica is today’s most promising modeling language in that it effectively unifies and generalizes previous object-oriented modeling languages and provides a sound basis for the basic concepts. Principles of Object-Oriented Modeling and Simulation with Modelica 2.1 introduces the latest methods of object-oriented component-based system modeling and simulation, and provides a tutorial and reference for the latest version of Modelica complete with a comprehensive overview of application model libraries from many domains. Executable examples are included from many areas–physics, mechanics, electrical systems, thermodynamics, flow systems, computer science, concurrent and real-time processes, biology, ecology chemistry, economy, etc. Designed for students, researchers, and engineers familiar with basic programming concepts, the text: Introduces the concepts of physical modeling, object-oriented modeling, and component-based modeling Includes both visual and textual modeling/programming Provides a complete yet informal overview of the Modelica language Demonstrates modeling examples for a wide range of applications Acts as a reference guide for the most commonly used Modelica libraries Features the current version of Modelica 2.1 including some anticipated extentions Its flexible format, comprehensive coverage of the field, and practical focus makes Principles of Object-Oriented Modeling and Simulation with Modelica 2.1 an indispensable teaching tool, a timely reference source for modeling and programming with Modelica, and a valuable hands-on guide for doing physical modeling in a broad range of application areas. Visit the book Web pa e www.mathcore.com/drmodelica for samples of executable models, teaching material, interactive tutorials, and recent updates of the book.
TL;DR: The background and tools for a port-based approach to integrated modeling and simulation of physical systems and their controllers, with parameters that are directly related to the real-world system, thus improving insight and direct feedback on modeling decisions.
16 Feb 2004
TL;DR: An innovative methodology for automatically generating the energy models of a versatile and parametric on-chip communication IP (STBus) that has been extensively benchmarked with the high-level systemC simulation of a real world multi-processor platform (MP-ARM).
Abstract: Today's system on chip (SoC) technology can achieve unprecedented computing speed that is shifting the IC design bottleneck from computation capacity to communication bandwidth and flexibility. This paper presents an innovative methodology for automatically generating the energy models of a versatile and parametric on-chip communication IP (STBus). Eventually, those models are linked to a standard systemC simulator, running at BCA and TLM abstraction level. To make the system power simulation fast and effective, we enhanced the STBus class library with a new set of power profiling features ("Power API"), allowing to perform power analysis either statically (i.e.: total avg. power) or at simulation runtime (i.e.: dynamic profiling). In addition to random patterns, our methodology has been extensively benchmarked with the high-level systemC simulation of a real world multi-processor platform (MP-ARM). It consists of four ARM7TDMI processors accessing a number of peripheral targets (including several banks of SRAMs, Interrupt's slaves and ROMs) through the STBus communication infrastructure. A remarkable amount of SW layers are executed on top of MP-ARM platform, including a distributed real-time operating system (RTEMS) and a set of multi-tasking DSP applications. The power analysis of the benchmark platform proves to be effective and highly correlated, with an average error of 9% and a RMS of 0.015 mW vs. the reference (i.e. gate level) power figures.
01 Jan 2004
TL;DR: In this paper, a dynamic model is used to describe the driver-vehicle interaction for a generic transient and to simulate the vehicle driveline, the internal combustion engine (ICE) and the electric motor/generator (EM).
Abstract: The paper focuses on the simulation, analysis and control of the energy flows in a parallel hybrid electric vehicle (HEV). HEVs operation is concerned with the on board conversion of chemical, electrical and mechanical energy and its optimal control is essential in order to increase the global system efficiency. A dynamic model is used to describe the driver-vehicle interaction for a generic transient and to simulate the vehicle driveline, the internal combustion engine (ICE) and the electric motor/generator (EM). An estimate of future vehicle load is performed with a neural network to optimize the supervisory control strategy during the estimated future time window. A description of the whole model is presented and the results obtained from the simulation of for a real driving cycle are reported.
Dissertation•
18 Jun 2004
01 Jan 2004
TL;DR: This research presents a novel approaches to physical system simulation called "Smart Cassandra", which automates the very labor-intensive and therefore time-heavy and expensive process of designing and simulating physical systems.
Abstract: Mathematical modeling and simulation of complex physical systems is emerging as a key technology in engineering. Modern approaches to physical system simulation allow users to specify simulation mo ...
10 Jun 2004
TL;DR: In this paper, a simulation model of the electric part of a grid connected microturbine (MT) is presented, which contains a detailed representation of the main components of electric system that are the permanent magnet synchronous machine and the static frequency changer.
Abstract: This paper presents a simulation model of the electric part of a grid connected microturbine (MT). The model contains a detailed representation of the main components of the electric system that are the permanent magnet synchronous machine and the static frequency changer. The microturbine is controlled so that the energy is exchanged with unity displacement factor. The simulation results obtained with the model using SimPowerSystems software were compared with experimental results obtained with a Capstone 30 kW microturbine. Finally, the simulation model is used to analyze the microturbine performance during steady state and transients such as grid voltage and phase unbalances and operation under grid polluted voltage.
TL;DR: In this article, the authors presented a research aimed at introducing modeling and simulation as a major methodological approach for enhancing power engineering education, and several implementations of the teaching examples are outlined.
Abstract: This paper resulted from the research aimed at introducing modeling and simulation as a major methodological approach for enhancing power engineering education. The reasons for such an approach are explained first. Different options and uses of the modeling and simulation tools are discussed next. Several implementations of the teaching examples are outlined. The paper ends with the conclusions reached based on the study.
TL;DR: Robinson et al. as mentioned in this paper compared two-and three-dimensional (2D and 3D) versions of ALEGRA-HEDP and found that 2D simulations overestimate the mass ablation rate by a factor of 10-100 with respect to the 3D case, causing pre-mature motion of the array.
Abstract: The two- and three-dimensional (2D and 3D) versions of ALEGRA-HEDP [A. C. Robinson and C. J. Garasi, “Three-dimensional Z-pinch wire array modeling,” Computer Physics Communications, submitted] have been utilized to simulate discrete wire effects including precursor formation in 2D (r-θ plane) and nonuniform axial ablation (3D). Comparisons made between 2D and 3D simulations indicate that 2D simulations overestimate the mass ablation rate by a factor of 10–100 with respect to the 3D case, causing pre-mature motion of the array with respect to experimental data. Additionally, the 2D case advects a factor of 5 more current to axis than the 3D case. The integrity of the simulations is assessed by comparing the results to laser imaging of wire ablation and array trajectory information inferred from visible and x-ray imaging. Comparisons to previously proposed ablation models are also presented. These simulations represent the first high-fidelity three-dimensional calculations of wire-array pinch geometries.
04 Oct 2004
TL;DR: The meanings of modern M&S and its architecture are discussed, some focusing points in recent research and application are discussed and some conclusions are given.
Abstract: Today, M&S combined with High Performance Computing is becoming the third important means for recognizing and rebuilding the objective world besides the theory research and experiment research. At present, the tendency of system modeling and simulation technology is developing towards networkitization, virtualization, intelligentization, collaboratization and pervasivization. Based on the research fruits of paper1 and author's recent research projects, this paper further discusses the meanings of modern M&S and its architecture. Furthermore, some focusing points in recent research and application of M&S are also discussed and prospected, including networkitized M&S technology based on modern network techniques, M&S technology on synthetized nature environment, Intelligent system modeling and intelligent simulation system, M&S technology of complex system and open, complex, huge system, virtual prototyping engineering technology, high performance computer, pervasive simulation technology etc.. At last, some conclusions are given.
22 Mar 2004
TL;DR: An overview of various modeling techniques is presented, with emphasis on integral-equation based boundary-element techniques and numerical stability issues related to these techniques are discussed from a physical viewpoint.
Abstract: The finite impedance of silicon substrates has several consequences for the design and performance of ICs. In this paper, we discuss the state of the art in the areas of modeling and simulation of these effects. An overview of various modeling techniques is presented, with emphasis on integral-equation based boundary-element techniques. Numerical stability issues related to these techniques are discussed from a physical viewpoint. The impact on circuit design is considered by the means of specific examples.
22 Dec 2004
20 Jun 2004
TL;DR: In this paper, a real-time hardware-in-loop (HIL) test facility is used for testing all-electric ship propulsion systems, which can be used for wind energy research.
Abstract: Traditionally, off-line modeling and simulation has been the tool of choice for improving wind energy system control strategies their utility system integration. This paper exploits how a newly established real-time hardware-in-loop (HIL) test facility, designed for testing all-electric ship propulsion systems, can be utilized for wind energy research. The test site uses two 2.5 MW/220 rpm dynamometers and a 5 MW variable voltage and frequency converter to emulate a realistic dynamic environment, both mechanically and electrically. The facility is controlled by a digital real-time electric power system simulator (RTDS), capable of simulating electrical networks and control systems of substantial complexity, typically with 50 microseconds time step. Substantial I/O allows the feedback of measured quantities into the simulation. A 15 kW mock-up motor-generator set is used to demonstrate some critical aspects of the concept. From dynamic test results presented it is concluded that the proposed system shows great potential for development of a one-of-a-kind wind energy research platform.
01 Jan 2004
TL;DR: The main contributions of this paper are to identify the main obstacles to the systems engineering decomposition approach: identifying coupling at the appropriate level of abstraction and characterizing and processing uncertainty, and present the role of modeling and simulation in overcoming these shortcomings.
Abstract: To design today’s complex, multi-disciplinary systems, designers need a design method that allows them to systematically decompose a complex design problem into simpler sub-problems. Systems engineering provides such a framework. In an iterative, hierarchical fashion systems are decomposed into subsystems and requirements are allocated to these subsystems based on estimates of their attributes. In this paper, we investigate the role and limitations of modeling and simulation in this process of system decomposition and requirements flowdown. We first identify different levels of complexity in the estimation of system attributes, ranging from simple aggregation to complex emergent behavior. We also identify the main obstacles to the systems engineering decomposition approach: identifying coupling at the appropriate level of abstraction and characterizing and processing uncertainty. The main contributions of this paper are to identify these short-comings, present the role of modeling and simulation in overcoming these shortcomings, and discuss research directions for addressing these issues and expanding the role of modeling and simulation in the future.Copyright © 2004 by ASME
TL;DR: This example shows how the intelligent control models of the robots are first designed and tested via simulation and, when verified mapped to physical robots with DEVS-on-a-chip “brains” for execution.
Abstract: Modeling, design and testing of the software underlying distributed robotic systems is a challenging task, especially when a large number of mobile robots and task coordination are involved. Model continuity, the ability to use the same model of a system throughout its design phases, provides an effective way to manage this development complexity and maintain consistency of the software. In this paper, we describe the design and implementation of a team-formation multi-robot system. This is used as an example to demonstrate how a modeling and simulation environment, based on the DEVS formalism, can support model continuity in the design of distributed robotic systems. This example shows how the intelligent control models of the robots are first designed and tested via simulation and, when verified mapped to physical robots with DEVS-on-a-chip “brains” for execution.
06 Jun 2004
TL;DR: The usefulness of Teuta is demonstrated by modeling LAPW0, a distributed material science application, and the methodology for automatic generation of the simulation model from the UML model of an application is presented.
Abstract: In this paper we describe Teuta, which we have developed to provide tool support for the UML-based performance modeling of distributed and parallel applications. Teuta features include model checking and model traversing. Model checking is used to verify whether the model conforms to the UML specification. In addition, Teuta supports semantic model checking for the domain of high performance computing. For the generation of different model representations the model traversing is used. In addition, we present our methodology for automatic generation of the simulation model from the UML model of an application. This simulation model is used to evaluate the performance of the application. We demonstrate the usefulness of Teuta by modeling LAPW0, a distributed material science application.
01 Jan 2004
TL;DR: The paper discusses the simulation of pedestrian traffic flows in public buildings from a practical point of view and presents novel solutions to the modeling of both types of person groups.
Abstract: The paper discusses the simulation of pedestrian traffic flows in public buildings from a practical point of view: The models developed are intended for use in an operative early-warning system. They must be able to forecast how the situation will evolve in each room of the building for the near future. By evaluating possible measures they can be used as a tool that pro-actively avoids critical system states. A mesoscopic approach to creating these models is described and partially realized. It envisions groups of persons as modeling and simulation objects and thereby distinguishes between physical and logical (virtual) groups. The paper presents novel solutions to the modeling of both types of person groups. An example of a model described in XML and implemented with Java is demonstrated.