Showing papers on "Modeling and simulation published in 2001"
01 Jun 2001
TL;DR: The major focus of the paper is on averaged models of various kinds, but sampled-data models are also introduced and the importance of hierarchical modeling and simulation is emphasized.
Abstract: This paper reviews some of the major approaches to modeling and simulation in power electronics, and provides references that can serve as a starting point for the extensive literature on the subject. The major focus of the paper is on averaged models of various kinds, but sampled-data models are also introduced. The importance of hierarchical modeling and simulation is emphasized.
516 citations
21 Jul 2001
TL;DR: This paper presents an enhanced random mobility model for simulation-based studies of wireless networks that makes the movement trace of individual mobile stations more realistic than common approaches for random movement.
Abstract: This paper presents an enhanced random mobility model for simulation-based studies of wireless networks. Our approach makes the movement trace of individual mobile stations more realistic than common approaches for random movement.After giving a survey of mobility models found in the literature, we give a detailed mathematical formulation of our model and outline its advantages. The movement concept is based on random processes for speed and direction control in which the new values are correlated to previous ones. Upon a speed change event, a new target speed is chosen, and an acceleration is set to achieve this target speed. The principles for a direction change are similar. Moreover, we propose two extensions for modeling typical movement patterns of vehicles. Finally, we consider strategies for the nodes' border behavior (i.e., what happens when nodes move out of the simulation area) and point out a pitfall that occurs when using a bounded simulation area.
485 citations
TL;DR: This chapter reviews how the structure of the neuromusculoskeletal system is commonly represented in a multijoint model of movement, how modeling may be combined with optimization theory to simulate the dynamics of a motor task, and how model output can be analyzed to describe and explain muscle function.
Abstract: ▪ Abstract Recent interest in using modeling and simulation to study movement is driven by the belief that this approach can provide insight into how the nervous system and muscles interact to produce coordinated motion of the body parts. With the computational resources available today, large-scale models of the body can be used to produce realistic simulations of movement that are an order of magnitude more complex than those produced just 10 years ago. This chapter reviews how the structure of the neuromusculoskeletal system is commonly represented in a multijoint model of movement, how modeling may be combined with optimization theory to simulate the dynamics of a motor task, and how model output can be analyzed to describe and explain muscle function. Some results obtained from simulations of jumping, pedaling, and walking are also reviewed to illustrate the approach.
476 citations
Book•
01 Jan 2001TL;DR: The emphasis shifts from FORTRAN to C++, in recognition of the upsurge of object oriented programming in engineering simulations, and the CADAC4 software package provides eight C++ simulations, which range from UAVs, aircraft, missiles, and boosters to hypersonic aircraft with transfer vehicles for satellite rendezvous.
Abstract: Overview Mathematical Concepts in Modeling Frames and Coordinate Systems Kinematics of Translation and Rotation Quatrenions Translational Dynamics Attitude Dynamics Perturbation Equations of Steady and Unsteady Flight Three-Degree-of-Freedom Simulation Turbo-Ramjet Propulsion Five-Degree-of-Freedom Simulation Proportional Navigation Gimbaled Seekers GPS Six-Degree-of-Freedom Simulation Oblate Earth Model Aerodynamic Modeling Autopilots INS Modeling Monte Carlo Analysis Turbulence Modeling Cockpit Simulators Hardware-In-The-Loop Facilities Wargaming Real-Time Applications Appendix A: Matrices Appendix B: CADAC Primer Appendix C. Aerospace Simulations in C++ Appendix D. Analytical Foundation of Tensor Flight Dynamics.
476 citations
IBM1
TL;DR: In this article, the authors examine the sources and trends of process variability, the new challenges associated with the increase in within-die variability analysis, and propose a modeling and simulation methodology to deal with this variability.
Abstract: Process-induced variations are an important consideration in the design of integrated circuits. Until recently, it was sufficient to model die-to-die shifts in device performance, leading to the well known worst-case modeling and design methodology. However, current and near-future integrated circuits are large enough that device and interconnect parameter variations within the chip are as important as those same variations from chip to chip. This presents a new set of challenges for process modeling and characterization and for the associated design tools and methodologies. This paper examines the sources and trends of process variability, the new challenges associated with the increase in within-die variability analysis, and proposes a modeling and simulation methodology to deal with this variability.
448 citations
Book•
01 Jan 2001
TL;DR: The field of quantitative modeling of mineral processing equipment and the use of these models to simulate the actual behavior of ore dressing and coal washing as they are configured to work in industrial practice is covered.
Abstract: Dr. R. Peter King covers the field of quantitative modeling of mineral processing equipment and the use of these models to simulate the actual behavior of ore dressing and coal washing as they are configured to work in industrial practice. The material is presented in a pedagogical style that is particularly suitable for readers who wish to learn the wide variety of modeling methods that have evolved in this field. The models vary widely from one unit type to another. As a result each model is described in some detail.Wherever possible model structure is related to the underlying physical processes that govern the behaviour of particulate material in the processing equipment. Predictive models are emphasised throughout so that, when combined, they can be used to simulate the operation of complex mineral processing flowsheets. The development of successful simulation techniques is a major objective of the work that is covered in the text.* Covers all aspects of modeling and simulation* Provides all necessary tools to put teh theory into practice* Free CD ROM includedAuthor: King, R. Peter Publisher: Butterworth-Heinemann Illustration: N Language: ENG Title: Modeling and Simulation of Mineral Processing Systems Pages: 00416 (Encrypted PDF) On Sale: 2001-11-27 SKU-13/ISBN: 9780750648844 Category: Technology & Engineering : Material Science Category: Technology & Engineering : Mechanical Category: Technology & Engineering : Metallurgy
364 citations
28 Mar 2001
TL;DR: A hybrid systems approach to modeling the intra-cellular network using continuous differential equations to model the feedback mechanisms and mode-switching to describe the changes in the underlying dynamics.
Abstract: In a biological cell, cellular functions and the genetic regulatory apparatus are implemented and controlled by a network of chemical reactions in which regulatory proteins can control genes that produce other regulators, which in turn control other genes. Further, the feed-back pathways appear to incorporate switches that result in changes in the dynamic behavior of the cell. This paper describes a hybrid systems approach to modeling the intra-cellular network using continuous differential equations to model the feedback mechanisms and mode-switching to describe the changes in the underlying dynamics. We use two case studies to illustrate a modular approach to modeling such networks and describe the architectural and behavioral hierarchy in the underlying models. We describe these models using CHARON [2], a language that allows formal description of hybrid systems. We provide preliminary simulation results that demonstrate how our approach can help biologists in their analysis of noisy genetic circuits. Finally we describe our agenda for future work that includes the development of models and simulation for stochastic hybrid systems.
221 citations
29 Nov 2001
TL;DR: An "average modeling" approach is proposed to simplify the PWM inverter operation and to accelerate the simulation for control parameters adjusting purpose and simulation performance obtained with both modeling approaches are presented and compared.
Abstract: This paper presents a study on the modeling of a STATCOM (Static Synchronous Compensator) used for reactive power compensation on a distribution network. The power circuits of the D-STATCOM and the distribution network are modeled by specific blocks from the Power System Blockset while the control system is modeled by Simulink blocks. Static and dynamic performance of a /spl plusmn/3 MVar D-STATCOM on a 25-kV network is evaluated. An "average modeling" approach is proposed to simplify the PWM inverter operation and to accelerate the simulation for control parameters adjusting purpose. Simulation performance obtained with both modeling approaches are presented and compared.
142 citations
TL;DR: An overview of the state-of-the art in modeling and simulation, and studies to which extent current simulation technologies can effectively support the design process are presented.
Abstract: This article presents an overview of the state-of-the art in modeling and simulation, and studies to which extent current simulation technologies can effectively support the design process. For simulation-based design, modeling languages and simulation environments must take into account the special characteristics of the design process. For instance, languages should allow models to be easily updated and extended to accommodate the various analyses performed throughout the design process. Furthermore, the simulation software should be well integrated with the design tools so that designers and analysts with expertise in different domains can effectively collaborate on the design of complex artifacts. This review focuses in particular on modeling for design of multi-disciplinary engineering systems that combine continuous time and discrete time phenomena.
142 citations
TL;DR: The proposed formalism and DEVS are shown to be bisimilar, which emphasizes the role of variable structure models as an agency of modularization in specification and analysis tools that support adaptable system structures.
Abstract: As the number of flexible, adaptable systems grows so does the need for specification and analysis tools that support adaptable system structures. The increasing number of simulation tools that equip models with the capability of changing their behavior patterns, composition, and interactions raises the desire for a theoretical and methodological approach. A formalism is introduced based on DEVS which emphasizes the reflective nature of variable structure models. The proposed formalism and DEVS are shown to be bisimilar, which emphasizes the role of variable structure models as an agency of modularization. The formalism is used to reveal general problems and solutions in implementing variable structure models.
137 citations
TL;DR: The Galerkin h-p method as discussed by the authors is based on a generalized finite-element scheme with self-adaptive grid-and order construction and is connected to a time discretization of Rothe's type.
01 Jan 2001
TL;DR: This dissertation aims to provide a history of web exceptionalism from 1989 to 2002, a period chosen in order to explore its roots as well as specific cases up to and including the year in which descriptions of “Web 2.0” began to circulate.
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TL;DR: In this article, the authors present the theoretical development of a generic flexible aircraft model, which allows for the e exible degrees of freedom to be added to an existing simulation model of the vehicle's rigid-body dynamics.
Abstract: Theeffectsofe exibility on thee ightdynamicsoflargeaircraft havebeen shown to bequitesignie cant, especially as the frequencies of the elastic modes become lower and approach those of the rigid-body modes. The handling characteristics of such vehicles are altered signie cantly from those of a rigid vehicle, and the design of the e ightcontrol system may become drastically more complex. Consequently, the need to model accurately the dynamics of such vehicles, and to develop valid simulations, is becoming particularly acute. The theoretical development of a generic e exible-aircraft model is reviewed. This modeling technique allows for the e exible degrees of freedom to be added to an existing simulation model of the vehicle’ s rigid-body dynamics. The data necessary for modeling a specie c vehicle include aerodynamic stability derivatives, aerodynamic ine uence coefe cients, elastic mode shapes, modal frequencies and damping, and generalized masses. Two case studies are presented, both involving the developmentofmotion-basedsimulationsinNASALangleyResearchCenter’ ssimulationfacility.Thee rstexample investigatesanaircraftsimilaringeometrytotheB-1,whereasthesecondinvestigatesalargehighspeedcommercial transport. The dynamic responses (time and frequency domain ) for these vehicles are presented, along with the evaluations of the effects of dynamic aeroelasticity on their handling characteristics. The vehicle responses are critical to evaluating hardware and software requirements for simulation e delity, for example, visual and motion cues. Finally, a brief assessment of the effects of limitations of the simulation facility is presented. Limitations considered include digital time delay, motion hardware bandwidth, and motion washout logic.
IBM1
TL;DR: In this article, the authors examine the sources and trends of process variability, the new challenges associated with the increase in within-die variability analysis, and propose a modeling and simulation methodology to deal with this variability.
Abstract: Process-induced variations are an important consideration in the design of integrated circuits. Until recently, it was sufficient to model die-to-die shifts in device performance, leading to the well known worst-case modeling and design methodology. However, current and near-future integrated circuits are large enough that device and interconnect parameter variations within the chip are as important as those same variations from chip to chip. This presents a new set of challenges for process modeling and characterization and for the associated design tools and methodologies. This paper examines the sources and trends of process variability, the new challenges associated with the increase in within-die variability analysis, and proposes a modeling and simulation methodology to deal with this variability.
01 Feb 2001
TL;DR: The paper proposes a layered architectural framework to support agent based system development in a collaborative, multidisciplinary engineering setting, intended to form the basis for environments that support development of agents, in both performance and simulation modes, as well as in hybrid combination.
Abstract: The paper proposes a layered architectural framework to support agent based system development in a collaborative, multidisciplinary engineering setting. This architecture is viewed from two distinct perspectives. First, the environment must enable agent based modeling and simulation. Second, it should support concurrent (team oriented) engineering. The main focus is on the proposed layered architecture delineating various needs of an agent based system, thus supporting incremental specification design, implementation, and testing. In our discussions, we distinguish between performing agents and simulated agents. The former refers to agents as they are performing their tasks in real-world settings. The latter refers to agents that have their behavior simulated in a virtual environment. In these terms, the proposed framework is intended to form the basis for environments that support development of agents, in both performance and simulation modes, as well as in hybrid combination (both performing and simulated agents interacting at the same time). The proposed framework is a step toward realization of agent based systems under the umbrella of the simulation based acquisition (SBA) initiative of the US Department of Defense.
29 Nov 2001
TL;DR: In this paper, a unified method for modeling and simulation of electrical drives using state-space formulation in MATLAB/Simulink is presented, which has been successfully implemented in a simulation package called "Power System Blockset" (PSB) for use in MATLab/simulink environment.
Abstract: This paper presents a unified method for modeling and simulation of electrical drives using state-space formulation in MATLAB/Simulink. The proposed method has been successfully implemented in a simulation package called "Power System Blockset" (PSB) for use in MATLAB/Simulink environment. The principle of the modeling and simulation method is presented and the PSB operation is described. Application examples including a DC brushless motor drive and a direct torque control (DTC) induction motor drive are presented. Simulation results obtained with the PSB are presented to illustrate its possibilities.
11 Jul 2001
TL;DR: The approach is to show the difference from others in that it supports a hierarchical and modular modeling environment, and generates the command-level behavior of cyber attack scenario, and provides an efficient model building environment based on the experimental frame concept.
Abstract: The major objective of this paper is to develop the network security modeling and cyber attack simulation that is able to classify threats, specify attack mechanisms, verify protection mechanisms, and evaluate consequences. To do this, we have employed the advanced modeling and simulation concepts such as System Entity Structure / Model Base framework, DEVS (Discrete Event System Specification) formalism, and experimental frame concept underlying the object-oriented S/W environment. Our approach is to show the difference from others in that (i) it supports a hierarchical and modular modeling environment, (ii) it generates the command-level behavior of cyber attack scenario, (iii) it provides an efficient model building environment based on the experimental frame concept, and (iv) it supports the vulnerability analysis of given node on the network. Simulation test performed on sample network system will illustrate our techniques.
TL;DR: In this article, a method for modeling and simulation of the dynamics of vehicles subject to liquid slosh loads is presented, where the vehicle components are modeled as a multibody system, the sloshing liquiddynamics is determined from solving the instationary, incompressibleNavier-Stokes equations under consideration of free surfaces.
Abstract: A method for modeling and simulation of the dynamics ofvehicles subject to liquid slosh loads is presented. The vehiclecomponents are modeled as a multibody system, the sloshing liquiddynamics is determined from solving the instationary, incompressibleNavier–Stokes equations under consideration of free surfaces. Toanalyze the overall system dynamics, the concept of modular simulationis applied decomposing the dynamic system into subsystems. The rigidbody and fluid subsystems are modeled by separate software codes whichare coupled by the transfer of in- and output variables duringsimulation runtime.
IBM1
TL;DR: This paper examines the sources and trends of process variability, the new challenges associated with the increase in within-die variability analysis, and proposes a modeling and simulation methodology to deal with this variability.
Abstract: Process-induced variations are an important consideration in the design of integrated circuits. Until recently, it was sufficient to model die-to-die shifts in device performance, leading to the well known worst-case modeling and design methodology [1, 2]. However, current and near-future in-tegrated circuits are large enough that device and intercon-nect parameter variations within the chip are as important as those same variations from chip to chip. This presents a new set of challenges for process modeling and characterization and for the associated design tools and method-ologies. This paper examines the sources and trends of process variability, the new challenges associated with the increase in within-die variability analysis, and proposes a modeling and simulation methodology to deal with this variability.
04 Mar 2001
TL;DR: In this article, an extended averaged model is developed for a soft-switched bi-directional DC-DC converter for high-power applications, and the proposed technique can be applied to other Bi-DDC power converters with a high-frequency isolation transformer.
Abstract: In this paper, an extended averaged model is developed for a soft-switched bi-directional DC-DC converter for high-power applications. The proposed technique can be applied to other bi-directional DC-DC power converters with a high-frequency isolation transformer. Simulation results of Matlab/Simulink using the proposed average model are compared to those of detailed circuit simulation and experimental results to confirm the validity of this technique.
TL;DR: In this article, a new fractal scaling model is proposed for use in aquifer heterogeneity modeling and simulation, which is obtained by subordination of fractional Brownian motion, providing a unifying framework for scaling models of heterogeneity in that it can also be tuned continuously between these models.
Abstract: A new fractal scaling model is proposed for use in aquifer heterogeneity modeling and simulation. The new model, which is obtained by subordination of fractional Brownian motion, provides a unifying framework for scaling models of heterogeneity in that it includes previous scaling models as special cases and can also be tuned continuously between these models. Choosing the subordinator to be a lognormal distribution results in a non-Gaussian scaling model with a moderate degree of variability that matches data better than previous fractal scaling models, thus providing more accurate heterogeneity representations for use in stochastic flow and transport predictions. Two new stochastic simulation algorithms are constructed from the new models, one based on sequential simulation algorithms and the other based on probability field simulation. Both algorithms can be made conditional on available measurements.
TL;DR: In this article, a finite composite beam element with piezoelectric actuators and sensors is used to model the active vibration control of beam structures equipped with PDEs.
Abstract: The active damping of structures is an important emerging field. In this context, it is necessary to be able to develop new control methods for flexible structures and simulate their effects. In order to be able to deal with the optimization of active device locations, spillover and any other general problems linked to control and model reduction, a simple but sufficiently rich model is very useful. This is the reason why this technical note deals with the modeling and simulation of the active vibration control of beam structures using piezoelectric actuators and sensors. In order to model beam structures equipped with piezoelectric devices, we develop a simple finite composite beam element, taking into account the properties of piezoelectric elements. This model uses six mechanical degrees of freedom and four electric degrees of freedom. Then, a linear quadratic regulator method is used to compute the control, including the implementation of a state observer. Several simulations are presented.
Book•
25 Oct 2001
TL;DR: This paper presents a new approach to modeling, simulation and Control of Non-linear Dynamical Systems called Fuzzy-Fractal Approach for Adaptive Model-Based Control.
Abstract: Introduction to Modeling, Simulation and Control of Non-linear Dynamical Systems. Fuzzy Logic for Modeling Neural Networks for Control. Genetic Algorithms and Fractal Theory for Modeling and Simulation. Fuzzy-Fractal Approach for Adaptive Model-Based Control. Advanced Applications of Automated Modeling and Simulation. Advanced Applications of Automated Mathematical Modeling and Simulation. Advanced Applications of Adaptive Model-Based Control.
TL;DR: The state-of-the art in computer-aided tools for drying environment are provided and mathematical modeling and simulation for process calculation and equipment design is discussed in depth.
Abstract: A great progress has been done in computer software and hardware, which obviously broaden the application of computers to drying technologies. This paper provides the state-of-the art in computer-aided tools for drying environment. The following applications of computers are identified and discussed in depth: mathematical modeling and simulation for process calculation and equipment design (microscale approach– at the level of a single drop or particle, and macroscale approach– at the level of a dryer or drying system); process control; modeling tools; software packages; artificial intelligence systems; databases and information transfer.
TL;DR: The current status of the work in this field is reported and the application to the road network of the downtown area of Duisburg is discussed and the efficiency of even microscopic simulation models is high enough to allow for reproduce the flow of whole networks in multiple real time.
01 Jan 2001
TL;DR: Simulation models of autonomous agents make it possible to take into consideration (and answer) questions about economic evaluation and process-oriented control more plausibly than current approaches are able to do.
Abstract: Traditional modelling approaches (mainly stemming from technically oriented application domains) have shown themselves increasingly inadequate in supporting the economic and organisational planning processes of hospitals. One of the major reasons for this problem is neglect of human decision making and behaviour as a relevant influence on the performance of such systems. In this paper, we show how the problem can be overcome by integrating agent technology into current modelling approaches. Simulation models of autonomous agents make it possible to take into consideration (and answer) questions about economic evaluation and process-oriented control more plausibly than current approaches are able to do.
Patent•
28 Sep 2001
TL;DR: In this paper, a system and method for identifying chemical, biological or nuclear attacks or hazards occurring within a large area which combines data derived from a modeling and simulation operation with a surveillance data input is presented.
Abstract: A surveillance system and method for identifying chemical, biological or nuclear attacks or hazards occurring within a large area which combines data derived from a modeling and simulation operation with a surveillance data input. The modeling and simulation operation involves continuous periodic runs of multiple scenarios for various biological, chemical and nuclear agents in various concentrations for a given location. Using real time weather data for each location, a model is made in a database of the effect various concentrations of agents would have at that location and this simulated model is processed. The surveillance data input monitors actual human signs and symptoms for the modeled area. This data with real time weather data is compared with the results of modeling and simulation data for the area to determine if a pattern matching that for any modeled agent is present.
01 Jan 2001
01 Jan 2001
TL;DR: This paper will describe how modeling and simulation (M&S) is applied to answer a wide variety of design and performance evaluation questions and will depict a series of simulation-based engineering projects that build on the Army's simulation investments as a tool to investigate and answer real-world vehicle design, acquisition, and engineering support questions.
Abstract: In support of the Department of Defense (DOD) mandated acquisition reform initiatives to reduce vehicle-related life cycle costs and time-lines, the Tank-automotive and Armaments Research, Development and Engineering Center (TARDEC) is using simulation-based acquisition strategies to investigate the dynamic performance of wheeled and tracked ground vehicles throughout the vehicle development, testing, and fielding life cycle process. The paper will describe how modeling and simulation (M&S) is applied to answer a wide variety of design and performance evaluation questions and will depict a series of simulation-based engineering projects that build on the Army's simulation investments as a tool to investigate and answer real-world vehicle design, acquisition, and engineering support questions.