The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Mojtaba Oghbaei - One of the best experts on this subject based on the ideXlab platform.
-
a state time formulation for dynamic Systems Simulation using massively parallel computing resources
Nonlinear Dynamics, 2005Co-Authors: Kurt S Anderson, Mojtaba OghbaeiAbstract:A novel state–time (ST) formulation for the Simulation and analysis of the dynamic behavior of complex multibody Systems is presented. The method proposes a computationally fast algorithm which is better able to fully exploit anticipated future immensely parallel computing resources (e.g. pecta flop machines and beyond) than existing multibody algorithms. The intent of the algorithm is to yield significantly reduced Simulation turnaround time in situations where massively parallel (>106 processors) computing resources are available to it. It is shown that as a consequence of such a ST discretization scheme, the system of governing equations yields a set of loosely coupled nonlinear algebraic equations which is at most quadratic in the ST variables, with significant linear components. As such, it is well-suited in structure for nonlinear algebraic equations solvers. The linear-quadratic (LQ) structure of these equations further permits the use of a special solution scheme, which is expected to yield superior performance relative to more traditional Newton–Raphson type schemes when applied to large general Systems.
-
A State–Time Formulation for Dynamic Systems Simulation Using Massively Parallel Computing Resources
Nonlinear Dynamics, 2005Co-Authors: Kurt S Anderson, Mojtaba OghbaeiAbstract:A novel state–time (ST) formulation for the Simulation and analysis of the dynamic behavior of complex multibody Systems is presented. The method proposes a computationally fast algorithm which is better able to fully exploit anticipated future immensely parallel computing resources (e.g. pecta flop machines and beyond) than existing multibody algorithms. The intent of the algorithm is to yield significantly reduced Simulation turnaround time in situations where massively parallel (>10^6 processors) computing resources are available to it. It is shown that as a consequence of such a ST discretization scheme, the system of governing equations yields a set of loosely coupled nonlinear algebraic equations which is at most quadratic in the ST variables, with significant linear components. As such, it is well-suited in structure for nonlinear algebraic equations solvers. The linear-quadratic (LQ) structure of these equations further permits the use of a special solution scheme, which is expected to yield superior performance relative to more traditional Newton–Raphson type schemes when applied to large general Systems.
Kurt S Anderson - One of the best experts on this subject based on the ideXlab platform.
-
a state time formulation for dynamic Systems Simulation using massively parallel computing resources
Nonlinear Dynamics, 2005Co-Authors: Kurt S Anderson, Mojtaba OghbaeiAbstract:A novel state–time (ST) formulation for the Simulation and analysis of the dynamic behavior of complex multibody Systems is presented. The method proposes a computationally fast algorithm which is better able to fully exploit anticipated future immensely parallel computing resources (e.g. pecta flop machines and beyond) than existing multibody algorithms. The intent of the algorithm is to yield significantly reduced Simulation turnaround time in situations where massively parallel (>106 processors) computing resources are available to it. It is shown that as a consequence of such a ST discretization scheme, the system of governing equations yields a set of loosely coupled nonlinear algebraic equations which is at most quadratic in the ST variables, with significant linear components. As such, it is well-suited in structure for nonlinear algebraic equations solvers. The linear-quadratic (LQ) structure of these equations further permits the use of a special solution scheme, which is expected to yield superior performance relative to more traditional Newton–Raphson type schemes when applied to large general Systems.
-
A State–Time Formulation for Dynamic Systems Simulation Using Massively Parallel Computing Resources
Nonlinear Dynamics, 2005Co-Authors: Kurt S Anderson, Mojtaba OghbaeiAbstract:A novel state–time (ST) formulation for the Simulation and analysis of the dynamic behavior of complex multibody Systems is presented. The method proposes a computationally fast algorithm which is better able to fully exploit anticipated future immensely parallel computing resources (e.g. pecta flop machines and beyond) than existing multibody algorithms. The intent of the algorithm is to yield significantly reduced Simulation turnaround time in situations where massively parallel (>10^6 processors) computing resources are available to it. It is shown that as a consequence of such a ST discretization scheme, the system of governing equations yields a set of loosely coupled nonlinear algebraic equations which is at most quadratic in the ST variables, with significant linear components. As such, it is well-suited in structure for nonlinear algebraic equations solvers. The linear-quadratic (LQ) structure of these equations further permits the use of a special solution scheme, which is expected to yield superior performance relative to more traditional Newton–Raphson type schemes when applied to large general Systems.
J L M Fernandes - One of the best experts on this subject based on the ideXlab platform.
-
hybrid photovoltaic thermal pv t solar Systems Simulation with simulink matlab
Solar Energy, 2010Co-Authors: R M Da Silva, J L M FernandesAbstract:The purpose of this work consists in thermodynamic modeling of hybrid photovoltaic-thermal (PV/T) solar Systems, pursuing a modular strategy approach provided by Simulink/Matlab. PV/T solar Systems are a recently emerging solar technology that allows for the simultaneous conversion of solar energy into both electricity and heat. This type of technology present some interesting advantages over the conventional ''side-by-side'' thermal and PV solar Systems, such as higher combined electrical/thermal energy outputs per unit area, and a more uniform and aesthetical pleasant roof area. Despite the fact that early research on PV/T Systems can be traced back to the seventies, only recently it has gained a renewed impetus. In this work, parametric studies and annual transient Simulations of PV/T Systems are undertaken in Simulink/Matlab. The obtained results show an average annual solar fraction of 67%, and a global overall efficiency of 24% (i.e. 15% thermal and 9% electrical), for a typical four-person single-family residence in Lisbon, with p-Si cells, and a collector area of 6 m{sup 2}. A sensitivity analysis performed on the PV/T collector suggests that the most important variable that should be addressed to improve thermal performance is the photovoltaic (PV) module emittance. Based on those results, some additional improvementsmore » are proposed, such as the use of vacuum, or a noble gas at low-pressure, to allow for the removal of PV cells encapsulation without air oxidation and degradation, and thus reducing the PV module emittance. Preliminary results show that this option allows for an 8% increase on optical thermal efficiency, and a substantial reduction of thermal losses, suggesting the possibility of working at higher fluid temperatures. The higher working temperatures negative effect in electrical efficiency was negligible, due to compensation by improved optical properties. The Simulation results are compared with experimental data obtained from other authors and perform reasonably well. The Simulink modeling platform has been mainly used worldwide on Simulation of control Systems, digital signal processing and electric circuits, but there are very few examples of application to solar energy Systems modeling. This work uses the modular environment of Simulink/Matlab to model individual PV/T system components, and to assemble the entire installation layout. The results show that the modular approach strategy provided by Matlab/Simulink environment is applicable to solar Systems modeling, providing good code scalability, faster developing time, and simpler integration with external computational tools, when compared with traditional imperative-oriented programming languages. (author)« less
Jeffrey S. Smith - One of the best experts on this subject based on the ideXlab platform.
-
Creating Realistic Human Behavior in Physical Security Systems Simulation
2010Co-Authors: Volkan Ustun, Jeffrey S. SmithAbstract:Physical security Systems (PSS) are designed to prevent access to a facility by intruders, detect the presence of intruders, or facilitate the capture or neutralization of intruders once they are detected, without negatively impacting the intended users of the facility, or neutrals. The application domains for PSS include banks, retail stores, schools, airports, subway stations and military installations, where the intention of the intruder can range from simple theft, to kidnap or mayhem to total facility destruction, and intruder mitigation can range from discouraging (in the case of shoplifting, e.g.) to alerting (in the case of burglary, e.g.), to capture and confinement or neutralization (in the case of facility destruction). These Systems generally include a combination of physical barriers, human guards, and sensor-based detection Systems such as video surveillance Systems. Furthermore, the tactics and policies for the security personnel are also integral to the overall PSS. The primary goal here is to assess the effectiveness of a PSS (both the sensor placement and the security policy of the personnel) for detecting intruders and mitigating their impact in compliance with the organization’s goals (e.g. deterrence, detection etc.). Other questions of interest that contribute to the primary goal include but are not limited to: • Is the PSS robust and effective against different tactics used by intruders (e.g. stealth, deceit, and force)? • What will be the effect of a change in physical security design on intruder behavior? • What should be the rules of engagement for security personnel to best mitigate the risks imposed by intruders? The complex interactions among guards, intruders, and neutral entities as well as the interactions between these entities and the environment, complicate analysis of these Systems (for instance, a fundamental problem in PSS is to distinguish an intruder from a neutral based on behavior) which is often limited to static "line of sight" and "field of view" models designed to help with camera placement and guard patrol path determination. Existing Simulation-based analysis methodologies include only crude and often hard-coded implementations of behavioral responses to predetermined situations for the guards, intruders, and neutrals. This limits the analysis capabilities of these models and makes creating them very time consuming and expensive.
-
Human behavior representation in physical security Systems Simulation
2009Co-Authors: Jeffrey S. Smith, Volkan UstunAbstract:Physical security Systems are designed to prevent access to a facility by intruders, detect the presence of intruders, or facilitate the capture of intruders once they are detected. These Systems generally include a combination of physical barriers, human guards, and sensor-based detection Systems such as video surveillance Systems. Because of the complex interactions between guard, intruder, and neutral entities as well as the interactions between these entities and the environment, analysis of these Systems is very difficult and is often limited to static "line of sight" and "field of view" models designed to help with camera placement. Existing Simulation-based analysis methodologies include only crude and often hard-coded implementations of human behaviors for the guard, intruders, and neutrals. This limits the analysis capabilities of these Systems. In response, this research develops a computational framework that supports realistic computer characters (or agents) that can operate within physical security system Simulations. The outputs of these Simulations can then be used to analyze the effectiveness of the tested physical security system configurations and to design more effective physical security Systems. The proposed computational framework is comprised of three components: a spatial model, a temporal model, and a representation of the application domain. As the spatial model, a conceptual data model named Hierarchical Graph Representation for Scenes (HIGHRES) is developed to formally represent the static features of the environment in a Simulation-friendly structure. A Behavior-Intuition Framework for Realistic Agents (ABIRA) is devised as a temporal model to realistically model the decision making activities of the agents. A retail store security system is selected as the sample application domain to demonstrate the capabilities of the proposed framework and furthermore, to validate the behavior emerging from the proposed computational models. The primary contribution of this work is twofold: a generic, extensible computational framework to emulate realistic human decision making and the integrated physical security Systems Simulation framework. This integrated Simulation framework is capable of conducting Simulation experiments to analyze the effectiveness of different physical security configurations that are comprised of both the physical security measures themselves and the security policies that manage them.
-
Winter Simulation Conference - Mental Simulation for creating realistic behavior in physical security Systems Simulation
2008 Winter Simulation Conference, 2008Co-Authors: Volkan Ustun, Jeffrey S. SmithAbstract:Mental Simulation is proposed by cognitive psychologists as a candidate to model the human reasoning process. In this paper, we propose a methodology that models mental Simulation to create realistic human behavior in simulated environments. This methodology is used to generate realistic intruder and guard behavior in physical security Systems Simulation. The behaviors include moving to a target while avoiding detection/capture for intruders and following and apprehending intruders for guards.
Wen Chuan-yuan - One of the best experts on this subject based on the ideXlab platform.
-
Systems, Simulation Systems and Their Theories
Computer Simulation, 2009Co-Authors: Wen Chuan-yuanAbstract:This paper reviews, analyzes and explains the essentials, correlations and development of Systems, system theories, original Systems, Simulation Systems, similarity theory and system Simulation combinatory theory from the point of view of fundamental theories, concepts, methods and evolutional rules. Then conclusions are drawn accordingly.
