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1

Transistor Modeling using Advanced Circuit Simulator Technology  

Microsoft Academic Search

Abstract KRIPLANI NIKHIL, M. Transistor Modeling using advanced circuit simulator technology. (Under the direction of Michael B. Steer) The advanced MOSFET model based on the Berkeley Short Channel IGFET

NIKHIL M. KRIPLANI

2

PRODUCT DEVELOPMENT PROCESS MODELING USING ADVANCED SIMULATION  

Microsoft Academic Search

This paper presents a product development process modeling and analysis technique using advanced simulation. The model computes the probability distribution of lead time in a resource -constrained project network where iterations take place among sequential, parallel and overlapped tasks. The model uses the design structure matrix representation to capture the information flows between tasks. In each simulation run, the expected

Soo-Haeng Cho; Steven D. Eppinger

2001-01-01

3

DEVELOPMENT OF THE ADVANCED UTILITY SIMULATION MODEL  

EPA Science Inventory

The paper discusses the development of the Advanced Utility Simulation Model (AUSM), developed for the National Acid Precipitation Assessment Program (NAPAP), to forecast air emissions of pollutants from electric utilities. USM integrates generating unit engineering detail with d...

4

METC Gasifier Advanced Simulation (MGAS) model  

SciTech Connect

Morgantown Energy Technology Center is developing an advanced moving-bed gasifier, which is the centerpiece of the Integrated Gasifier Combined-Cycle (IGCC) system, with the features of good efficiency, low cost, and minimal environmental impact. A mathematical model of the gasifier, the METC-Gasifier Advanced Simulation (MGAS) model, has been developed for the analysis and design of advanced gasifiers and other moving-bed gasifiers. This report contains the technical and the user manuals of the MGAS model. The MGAS model can describe the transient operation of coflow, counterflow, or fixed-bed gasifiers. It is a one-dimensional model and can simulate the addition and withdrawal of gas and solids at multiple locations in the bed, a feature essential for simulating beds with recycle. The model describes the reactor in terms of a gas phase and a solids (coal or char) phase. These phases may exist at different temperatures. The model considers several combustion, gasification, and initial stage reactions. The model consists of a set of mass balances for 14 gas species and three coal (pseudo-) species and energy balances for the gas and the solids phases. The resulting partial differential equations are solved using a finite difference technique.

Syamlal, M. [EG and G Washington Analytical Services Center, Inc., Morgantown, WV (United States); Bissett, L.A. [USDOE Morgantown Energy Technology Center, WV (United States)

1992-01-01

5

Advances in modeling and simulation of vacuum electronic devices  

Microsoft Academic Search

Recent advances in the modeling and simulation of vacuum electronic devices are reviewed. Design of these devices makes use of a variety of physical models and numerical code types. Progress in the development of these models and codes is outlined and illustrated with specific examples. The state of the art in device simulation is evolving to the point such that

THOMAS M. ANTONSEN; ALFRED A. MONDELLI; BARUCH LEVUSH; JOHN P. VERBONCOEUR; C. K. Birdsall

1999-01-01

6

ADVANCED UTILITY SIMULATION MODEL DESCRIPTION OF MODIFICATIONS TO THE STATE LEVEL MODEL (VERSION 3.0)  

EPA Science Inventory

The report documents modifications to the state level model portion of the Advanced Utility Simulation Model (AUSM), one of four stationary source emission and control cost forecasting models developed for the National Acid Precipitation Assessment Program (NAPAP). The AUSM model...

7

Advanced Utility Simulation Model Description of the National Loop (Version 3.0).  

National Technical Information Service (NTIS)

The report describes the national loop of the Advanced Utility Simulation Model (AUSM), simulating strategic planning in the electric utility industry. Acting as a preprocessor to the second component of AUSM (the state model), the national loop simulates...

R. L. Capone L. G. Jones

1988-01-01

8

Enabling Advanced Modeling and Simulations for Fuel-Flexible Combustors  

SciTech Connect

The overall goal of the present project is to enable advanced modeling and simulations for the design and optimization of fuel-flexible turbine combustors. For this purpose we use a high-fidelity, extensively-tested large-eddy simulation (LES) code and state-of-the-art models for premixed/partially-premixed turbulent combustion developed in the PI's group. In the frame of the present project, these techniques are applied, assessed, and improved for hydrogen enriched premixed and partially premixed gas-turbine combustion. Our innovative approaches include a completely consistent description of flame propagation, a coupled progress variable/level set method to resolve the detailed flame structure, and incorporation of thermal-diffusion (non-unity Lewis number) effects. In addition, we have developed a general flamelet-type transformation holding in the limits of both non-premixed and premixed burning. As a result, a model for partially premixed combustion has been derived. The coupled progress variable/level method and the general flamelet tranformation were validated by LES of a lean-premixed low-swirl burner that has been studied experimentally at Lawrence Berkeley National Laboratory. The model is extended to include the non-unity Lewis number effects, which play a critical role in fuel-flexible combustor with high hydrogen content fuel. More specifically, a two-scalar model for lean hydrogen and hydrogen-enriched combustion is developed and validated against experimental and direct numerical simulation (DNS) data. Results are presented to emphasize the importance of non-unity Lewis number effects in the lean-premixed low-swirl burner of interest in this project. The proposed model gives improved results, which shows that the inclusion of the non-unity Lewis number effects is essential for accurate prediction of the lean-premixed low-swirl flame.

Heinz Pitsch

2010-05-31

9

ADVANCED TECHNIQUES FOR RESERVOIR SIMULATION AND MODELING OF NONCONVENTIONAL WELLS  

SciTech Connect

Nonconventional wells, which include horizontal, deviated, multilateral and ''smart'' wells, offer great potential for the efficient management of oil and gas reservoirs. These wells are able to contact larger regions of the reservoir than conventional wells and can also be used to target isolated hydrocarbon accumulations. The use of nonconventional wells instrumented with downhole inflow control devices allows for even greater flexibility in production. Because nonconventional wells can be very expensive to drill, complete and instrument, it is important to be able to optimize their deployment, which requires the accurate prediction of their performance. However, predictions of nonconventional well performance are often inaccurate. This is likely due to inadequacies in some of the reservoir engineering and reservoir simulation tools used to model and optimize nonconventional well performance. A number of new issues arise in the modeling and optimization of nonconventional wells. For example, the optimal use of downhole inflow control devices has not been addressed for practical problems. In addition, the impact of geological and engineering uncertainty (e.g., valve reliability) has not been previously considered. In order to model and optimize nonconventional wells in different settings, it is essential that the tools be implemented into a general reservoir simulator. This simulator must be sufficiently general and robust and must in addition be linked to a sophisticated well model. Our research under this five year project addressed all of the key areas indicated above. The overall project was divided into three main categories: (1) advanced reservoir simulation techniques for modeling nonconventional wells; (2) improved techniques for computing well productivity (for use in reservoir engineering calculations) and for coupling the well to the simulator (which includes the accurate calculation of well index and the modeling of multiphase flow in the wellbore); and (3) accurate approaches to account for the effects of reservoir heterogeneity and for the optimization of nonconventional well deployment. An overview of our progress in each of these main areas is as follows. A general purpose object-oriented research simulator (GPRS) was developed under this project. The GPRS code is managed using modern software management techniques and has been deployed to many companies and research institutions. The simulator includes general black-oil and compositional modeling modules. The formulation is general in that it allows for the selection of a wide variety of primary and secondary variables and accommodates varying degrees of solution implicitness. Specifically, we developed and implemented an IMPSAT procedure (implicit in pressure and saturation, explicit in all other variables) for compositional modeling as well as an adaptive implicit procedure. Both of these capabilities allow for efficiency gains through selective implicitness. The code treats cell connections through a general connection list, which allows it to accommodate both structured and unstructured grids. The GPRS code was written to be easily extendable so new modeling techniques can be readily incorporated. Along these lines, we developed a new dual porosity module compatible with the GPRS framework, as well as a new discrete fracture model applicable for fractured or faulted reservoirs. Both of these methods display substantial advantages over previous implementations. Further, we assessed the performance of different preconditioners in an attempt to improve the efficiency of the linear solver. As a result of this investigation, substantial improvements in solver performance were achieved.

Louis J. Durlofsky; Khalid Aziz

2004-08-20

10

Modelling and Simulation of the Advanced Plasma Source  

SciTech Connect

Plasma ion assisted-deposition (PIAD) is a combination of conventional thermal evaporation deposition and plasma-beam surface modification; it serves as a well-established technology for the creation of high quality coatings on mirrors, lenses, and other optical devices. It is closely related to ion-assisted deposition to the extent that electrons preserve quasineutrality of the ion beam. This paper investigates the Advanced Plasma Source (APS), a plasma beam source employed for PIAD. A field enhanced glow discharge generates a radially expanding plasma flow with an ion energy of about 80-120 eV. Charge exchange collisions with the neutral background gas (pressure 0.1 Pa and below) produce a cold secondary plasma, which expands as well. A model is developed which describes the primary ions by a simplified Boltzmann equation, the secondary ions by the equations of continuity and momentum balance, and the electrons by the condition of Boltzmann equilibrium. Additionally, quasineutrality is assumed. The model can be reduced to a single nonlinear differential equation for the velocity of the secondary ions, which has several removable singularities and one essential singularity, identified as the Bohm singularity. Solving the model yields macroscopic plasma features, such as fluxes, densities, and the electrical field. An add-on Monte-Carlo simulation is employed to calculate the ion energy distribution function at the substrate. All results compare well to experiments conducted at a commercial APS system.

Schroeder, Benjamin; Peter, Ralf [Lehrstuhl fuer Theoretische Elektrotechnik, Ruhr-Universitaet Bochum, Universitaetsstrasse 150, Bochum 44801 (Germany); Harhausen, Jens; Ohl, Andreas [INP Greifswald e.V., Felix - Hausdorff - Str. 2, Greifswald 17489 (Germany)

2011-08-15

11

Recent Advances in Underwater Acoustic Modelling and Simulation  

Microsoft Academic Search

A comprehensive review of international developments in underwater acoustic modelling is used to construct an updated technology baseline containing 107 propagation models, 16 noise models, 17 reverberation models and 25 sonar performance models. This updated technology baseline represents a 30% increase over a previous baseline published in 1996. When executed in higher-level simulations, these models can generate predictive and diagnostic

P. C. Etter

2001-01-01

12

RECENT ADVANCES IN UNDERWATER ACOUSTIC MODELLING AND SIMULATION  

Microsoft Academic Search

A comprehensive review of international developments in underwater acoustic modelling is used to construct an updated technology baseline containing 107 propagation models, 16 noise models, 17 reverberation models and 25 sonar performance models. This updated technology baseline represents a 30% increase over a previous baseline published in 1996. When executed in higher-level simulations, these models can generate predictive and diagnostic

P. C. ETTER

2001-01-01

13

Modeling of advanced alkaline electrolyzers: a system simulation approach  

Microsoft Academic Search

A mathematical model for an advanced alkaline electrolyzer has been developed. The model is based on a combination of fundamental thermodynamics, heat transfer theory, and empirical electrochemical relationships. A dynamic thermal model has also been developed. Comparisons between predicted and measured data show that the model can be used to predict the cell voltage, hydrogen production, efficiencies, and operating temperature.

Øystein Ulleberg

2003-01-01

14

Advanced 3D Photocathode Modeling and Simulations Final Report  

SciTech Connect

High brightness electron beams required by the proposed Next Linear Collider demand strong advances in photocathode electron gun performance. Significant improvement in the production of such beams with rf photocathode electron guns is hampered by the lack high-fidelity simulations. The critical missing piece in existing gun codes is a physics-based, detailed treatment of the very complex and highly nonlinear photoemission process.

Dimitre A Dimitrov; David L Bruhwiler

2005-06-06

15

ADVANCED UTILITY SIMULATION MODEL, PROGRAM DOCUMENTATION. STATE LEVEL MODEL (VERSION 1.0)  

EPA Science Inventory

The report is one of 11 in a series describing the initial development of the Advanced Utility Simulation Model (AUSM). The AUSM is one of four stationary source emission and control cost forecasting models developed by EPA for the National Acid Precipitation Assessment Program (...

16

ADVANCED UTILITY SIMULATION MODEL ANALYTICAL DOCUMENTATION STATE LEVEL MODEL (VERSION 1.0)  

EPA Science Inventory

The report is one of 11 in a series describing the initial development of the Advanced Utility Simulation Model (AUSM). The AUSM is one of four stationary source emission and control cost forecasting models developed by EPA for the National Acid Precipitation Assessment Program (...

17

ADVANCED UTILITY SIMULATION MODEL DOCUMENTATION OF SYSTEM DESIGN STATE LEVEL MODEL (VERSION 1.0)  

EPA Science Inventory

The report is one of 11 in a series describing the initial development of the Advanced Utility Simulation Model (AUSM) by the Universities Research Group on Energy (URGE) and its continued development by the Science Applications International Corporation (SAIC) research team. The...

18

Modeling emergency department operations using advanced computer simulation systems.  

PubMed

We developed a computer simulation model of emergency department operations using simulation software. This model uses multiple levels of preemptive patient priority; assigns each patient to an individual nurse and physician; incorporates all standard tests, procedures, and consultations; and allows patient service processes to proceed simultaneously, sequentially, repetitively, or a combination of these. Selected input data, including the number of physicians, nurses, and treatment beds, and the blood test turnaround time, then were varied systematically to determine their simulated effect on patient throughput time, selected queue sizes, and rates of resource utilization. Patient throughput time varied directly with laboratory service times and inversely with the number of physician or nurse servers. Resource utilization rates varied inversely with resource availability, and patient waiting time and patient throughput time varied indirectly with the level of patient acuity. The simulation can be animated on a computer monitor, showing simulated patients, specimens, and staff members moving throughout the ED. Computer simulation is a potentially useful tool that can help predict the results of changes in the ED system without actually altering it and may have implications for planning, optimizing resources, and improving the efficiency and quality of care. PMID:2916776

Saunders, C E; Makens, P K; Leblanc, L J

1989-02-01

19

Tutorial: Advances and challenges in healthcare simulation modeling  

Microsoft Academic Search

Simulation has been used for modeling healthcare systems for over forty years. In many respects it is the ideal approach for addressing healthcare issues, yet the relatively small number of successful implementations would suggest that (outside academia) it has been underused in the health sector, compared with manufacturing industry or defense. In this paper we present a review of applications

Sally C. Brailsford

2007-01-01

20

Advances in Modeling and Simulation of Grinding Processes  

Microsoft Academic Search

In the last decade the relevance of modeling and simulation of grinding processes has significantly risen which is caused by industrial needs and is indicated by the number of publications and research activities in this area. This keynote paper results from a collaborative work within the STC G and gives an overview of the current state of the art in

E. Brinksmeier; J. C. Aurich; E. Govekar; C. Heinzel; H.-W. Hoffmeister; F. Klocke; J. Peters; R. Rentsch; D. J. Stephenson; E. Uhlmann; K. Weinert; M. Wittmann

2006-01-01

21

Advanced modelling of failure mechanisms in aluminium sheet forming simulation  

Microsoft Academic Search

In this paper novel and efficient approaches to model localized necking and ductile fracture in sheet forming simulation using\\u000a the finite element method are presented. The stress-based forming limit curve is used to detect localized necking. Post-necking\\u000a is captured using a new concept called accelerated plastic thinning. A simple ductile fracture model was developed. Various\\u000a application examples demonstrate the capabilities

Holger Aretz; Stefan Keller; Rolf Vogt; Olaf Engler

2009-01-01

22

An advanced modeling approach for mask and wafer process simulation  

NASA Astrophysics Data System (ADS)

A new modeling technique to accurately represent the mask and wafer process behavior is presented. The lithography simulation can be done in three steps: i) mask simulation, ii) latent image calculations and iii) resist process simulation. The leading edge designs, such as 32 nm and beyond, require higher-fidelity models to adequately represent each of these actual processes. Effects previously considered secondary, have become more pronounced with each new technology node. In this approach, we utilized separate physical models for both mask and wafer processes. We demonstrate that the residual errors can be further reduced when nonlinear mappers are used in addition. The advantage of the presented approach compared to standard curve-fitting or statistics-based models is its predictive power and adaptive nature. The physical model parameters were calibrated by a genetic algorithm whose details were outlined in [1]. The nonlinear mapper model parameters were identified by a gradient descent method. Given the computational requirements for a practical solution, our approach uses graphics processors as well as CPUs as computation hardware.

Karakas, Ahmet; Elsen, Erich; Torunoglu, Ilhami; Andrus, Curtis

2010-09-01

23

Air Force Agency for Modeling and Simulation: Advancing Modeling and Simulation for the Warfighter.  

National Technical Information Service (NTIS)

In the mid 1990s General Ronald Fogleman, then U.S. Air Force (USAF) Chief of Staff, was determined to correct the deficiencies in modeling and simulation (M&S) that were uncovered in the months and years following Desert Storm. The existing models, techn...

R. DeForest

2009-01-01

24

Advancing botnet modeling techniques for military and security simulations  

NASA Astrophysics Data System (ADS)

Simulation environments serve many purposes, but they are only as good as their content. One of the most challenging and pressing areas that call for improved content is the simulation of bot armies (botnets) and their effects upon networks and computer systems. Botnets are a new type of malware, a type that is more powerful and potentially dangerous than any other type of malware. A botnet's power derives from several capabilities including the following: 1) the botnet's capability to be controlled and directed throughout all phases of its activity, 2) a command and control structure that grows increasingly sophisticated, and 3) the ability of a bot's software to be updated at any time by the owner of the bot (a person commonly called a bot master or bot herder.) Not only is a bot army powerful and agile in its technical capabilities, a bot army can be extremely large, can be comprised of tens of thousands, if not millions, of compromised computers or it can be as small as a few thousand targeted systems. In all botnets, their members can surreptitiously communicate with each other and their command and control centers. In sum, these capabilities allow a bot army to execute attacks that are technically sophisticated, difficult to trace, tactically agile, massive, and coordinated. To improve our understanding of their operation and potential, we believe that it is necessary to develop computer security simulations that accurately portray bot army activities, with the goal of including bot army simulations within military simulation environments. In this paper, we investigate issues that arise when simulating bot armies and propose a combination of the biologically inspired MSEIR infection spread model coupled with the jump-diffusion infection spread model to portray botnet propagation.

Banks, Sheila B.; Stytz, Martin R.

2011-05-01

25

Advanced Techniques for Reservoir Simulation and Modeling of Non-Conventional Wells  

SciTech Connect

This project targets the development of (1) advanced reservoir simulation techniques for modeling non-conventional wells; (2) improved techniques for computing well productivity (for use in reservoir engineering calculations) and well index (for use in simulation models), including the effects of wellbore flow; and (3) accurate approaches to account for heterogeneity in the near-well region.

Durlofsky, Louis J.

2000-08-28

26

Development and validation of an aero-engine simulation model for advanced controller design  

Microsoft Academic Search

This paper reports the results of a joint academic and industrial study on the development of a detailed simulation model to be used for research into advanced control strategies for civil turbofan aircraft engines. A comprehensive nonlinear dynamic model of a turbofan jet engine has been developed and validated against real industrial data. A switched, gain- scheduled, feedback control system

Sonny Martin; Iain Wallace; Declan G. Bates

2008-01-01

27

Modeling and simulation of manufacturing processes of advanced composite materials  

NASA Astrophysics Data System (ADS)

Models for autoclave curing of thermosetting matrix composites are briefly described along with models of manufacturing process models for thermoplastic matrix composites. These models can be used to obtain optimum cure cycles of composite materials. They are particularly useful since the cure cycle must be modified to account for the effect of internal heat generation at the thickness of composite laminate changes. They can be indispensable tools in finding appropriate rules for optimum cure cycles via expert systems.

Lee, Woo I.; Springer, George S.

28

ADVANCED UTILITY SIMULATION MODEL, DESCRIPTION OF THE NATIONAL LOOP (VERSION 3.0)  

EPA Science Inventory

The report is one of 11 in a series describing the initial development of the Advanced Utility Simulation Model (AUSM) by the Universities Research Group on Energy (URGE) and its continued development by the Science Applications International Corporation (SAIC) research team. The...

29

ADVANCED UTILITY SIMULATION MODEL, DATA BASE MAINTENANCE (VERSION 1.0)  

EPA Science Inventory

The report is one of 11 in a series describing the initial development of the Advanced Utility Simulation Model (AUSM) by the Universities Research Group on Energy (URGE) and its continued development by the Science Applications International Corporation (SAIC) research team. The...

30

Strategic Plan for Nuclear Energy -- Knowledge Base for Advanced Modeling and Simulation (NE-KAMS)  

Microsoft Academic Search

The Nuclear Energy Computational Fluid Dynamics Advanced Modeling and Simulation (NE-CAMS) system is being developed at the Idaho National Laboratory (INL) in collaboration with Bettis Laboratory, Sandia National Laboratory (SNL), Argonne National Laboratory (ANL), Utah State University (USU), and other interested parties with the objective of developing and implementing a comprehensive and readily accessible data and information management system for

Kimberlyn C. Mousseau

2011-01-01

31

Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC).  

SciTech Connect

The objective of the U.S. Department of Energy Office of Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC) is to provide an integrated suite of computational modeling and simulation (M&S) capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive-waste storage facility or disposal repository. Achieving the objective of modeling the performance of a disposal scenario requires describing processes involved in waste form degradation and radionuclide release at the subcontinuum scale, beginning with mechanistic descriptions of chemical reactions and chemical kinetics at the atomic scale, and upscaling into effective, validated constitutive models for input to high-fidelity continuum scale codes for coupled multiphysics simulations of release and transport. Verification and validation (V&V) is required throughout the system to establish evidence-based metrics for the level of confidence in M&S codes and capabilities, including at the subcontiunuum scale and the constitutive models they inform or generate. This Report outlines the nature of the V&V challenge at the subcontinuum scale, an approach to incorporate V&V concepts into subcontinuum scale modeling and simulation (M&S), and a plan to incrementally incorporate effective V&V into subcontinuum scale M&S destined for use in the NEAMS Waste IPSC work flow to meet requirements of quantitative confidence in the constitutive models informed by subcontinuum scale phenomena.

Schultz, Peter Andrew

2011-12-01

32

ADVANCED UTILITY SIMULATION MODEL, REPORT OF SENSITIVITY TESTING, CALIBRATION, AND MODEL OUTPUT COMPARISONS (VERSION 3.0) TAPE  

EPA Science Inventory

The report is one of 11 in a series describing the initial development of the Advanced Utility Simulation Model (AUSM) by the Universities Research Group on Energy (URGE) and its continued development by the Science Applications International Corporation (SAIC) research team. The...

33

Session 8: Modeling and simulation - advances in modeling low dimensional structures  

Microsoft Academic Search

This session presents recent advances in the simulation of low dimensional structures. The session begins with an invited paper by Klimeck et al., from Purdue. This paper reviews the progress towards atomistic 3D quantum transport of nano-scale semiconductor devices. Betti et al., from University of Pisa will then address shot noise in quasi one-dimensional FETs. The impact of strain on

Giuseppe Iannaccone

2008-01-01

34

Simulation of the Decadal Solar Signal with Advanced Chemistry-Climate Models -Improvements and Remaining Questions  

NASA Astrophysics Data System (ADS)

Considerable progress has been made in recent years in modeling the impact of decadal solar variability on Earth's atmosphere and climate. Comprehensive, global Chemistry-Climate Mod-els(CCMs)are now available which account for the influences of variations in solar UV radiation and particles on chemical, radiative and dynamical processes, and their interactions. Models with sufficiently high vertical resolution to simulate the tropical Quasi-Biennial-Oscillation (QBO) have been applied to investigate the interaction between solar variability and the QBO. New multi-decadal transient CCM simulations have been performed within the SPARC CCM-Val activity which allow for studying possible advantages of prescribing transient solar cycles instead of the traditional approach of using constant irradiance for solar minimum or maxi-mum. However, there are still discrepancies between the observed and simulated solar signals, and open questions remain. This presentation will give an overview of recent advancements in modeling the decadal solar signal in the atmosphere with special emphasis on the strengths and weaknesses of the new CCM simulations, and will discuss still unresolved issues.

Langematz, Ulrike

35

The Nuclear Energy Advanced Modeling and Simulation Enabling Computational Technologies FY09 Report  

SciTech Connect

In this document we report on the status of the Nuclear Energy Advanced Modeling and Simulation (NEAMS) Enabling Computational Technologies (ECT) effort. In particular, we provide the context for ECT In the broader NEAMS program and describe the three pillars of the ECT effort, namely, (1) tools and libraries, (2) software quality assurance, and (3) computational facility (computers, storage, etc) needs. We report on our FY09 deliverables to determine the needs of the integrated performance and safety codes (IPSCs) in these three areas and lay out the general plan for software quality assurance to meet the requirements of DOE and the DOE Advanced Fuel Cycle Initiative (AFCI). We conclude with a brief description of our interactions with the Idaho National Laboratory computer center to determine what is needed to expand their role as a NEAMS user facility.

Diachin, L F; Garaizar, F X; Henson, V E; Pope, G

2009-10-12

36

Strategic Plan for Nuclear Energy -- Knowledge Base for Advanced Modeling and Simulation (NE-KAMS)  

SciTech Connect

The Nuclear Energy Computational Fluid Dynamics Advanced Modeling and Simulation (NE-CAMS) system is being developed at the Idaho National Laboratory (INL) in collaboration with Bettis Laboratory, Sandia National Laboratory (SNL), Argonne National Laboratory (ANL), Utah State University (USU), and other interested parties with the objective of developing and implementing a comprehensive and readily accessible data and information management system for computational fluid dynamics (CFD) verification and validation (V&V) in support of nuclear energy systems design and safety analysis. The two key objectives of the NE-CAMS effort are to identify, collect, assess, store and maintain high resolution and high quality experimental data and related expert knowledge (metadata) for use in CFD V&V assessments specific to the nuclear energy field and to establish a working relationship with the U.S. Nuclear Regulatory Commission (NRC) to develop a CFD V&V database, including benchmark cases, that addresses and supports the associated NRC regulations and policies on the use of CFD analysis. In particular, the NE-CAMS system will support the Department of Energy Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Program, which aims to develop and deploy advanced modeling and simulation methods and computational tools for reliable numerical simulation of nuclear reactor systems for design and safety analysis. Primary NE-CAMS Elements There are four primary elements of the NE-CAMS knowledge base designed to support computer modeling and simulation in the nuclear energy arena as listed below. Element 1. The database will contain experimental data that can be used for CFD validation that is relevant to nuclear reactor and plant processes, particularly those important to the nuclear industry and the NRC. Element 2. Qualification standards for data evaluation and classification will be incorporated and applied such that validation data sets will result in well-defined, well-characterized data. Element 3. Standards will be established for the design and operation of experiments for the generation of new validation data sets that are to be submitted to NE-CAMS that addresses the completeness and characterization of the dataset. Element 4. Standards will be developed for performing verification and validation (V&V) to establish confidence levels in CFD analyses of nuclear reactor processes; such processes will be acceptable and recognized by both CFD experts and the NRC.

Kimberlyn C. Mousseau

2011-10-01

37

An educational training simulator for advanced perfusion techniques using a high-fidelity virtual patient model.  

PubMed

The operation of cardiopulmonary bypass procedure requires an advanced skill in both physiological and mechanical knowledge. We developed a virtual patient simulator system using a numerical cardiovascular regulation model to manage perfusion crisis. This article evaluates the ability of the new simulator to prevent perfusion crisis. It combined short-term baroreflex regulation of venous capacity, vascular resistance, heart rate, time-varying elastance of the heart, and plasma-refilling with a simple lumped parameter model of the cardiovascular system. The combination of parameters related to baroreflex regulation was calculated using clinical hemodynamic data. We examined the effect of differences in autonomous-nerve control parameter settings on changes in blood volume and hemodynamic parameters and determined the influence of the model on operation of the control arterial line flow and blood volume during the initiation and weaning from cardiopulmonary bypass. Typical blood pressure (BP) changes (hypertension, stable, and hypotension) were reproducible using a combination of four control parameters that can be estimated from changes in patient physiology, BP, and blood volume. This simulation model is a useful educational tool to learn the recognition and management skills of extracorporeal circulation. Identification method for control parameter can be applied for diagnosis of heart failure. PMID:22963152

Tokaji, Megumi; Ninomiya, Shinji; Kurosaki, Tatsuya; Orihashi, Kazumasa; Sueda, Taijiro

2012-09-11

38

Strategic Plan for Nuclear Energy -- Knowledge Base for Advanced Modeling and Simulation (NE-KAMS)  

SciTech Connect

NE-KAMS knowledge base will assist computational analysts, physics model developers, experimentalists, nuclear reactor designers, and federal regulators by: (1) Establishing accepted standards, requirements and best practices for V&V and UQ of computational models and simulations, (2) Establishing accepted standards and procedures for qualifying and classifying experimental and numerical benchmark data, (3) Providing readily accessible databases for nuclear energy related experimental and numerical benchmark data that can be used in V&V assessments and computational methods development, (4) Providing a searchable knowledge base of information, documents and data on V&V and UQ, and (5) Providing web-enabled applications, tools and utilities for V&V and UQ activities, data assessment and processing, and information and data searches. From its inception, NE-KAMS will directly support nuclear energy research, development and demonstration programs within the U.S. Department of Energy (DOE), including the Consortium for Advanced Simulation of Light Water Reactors (CASL), the Nuclear Energy Advanced Modeling and Simulation (NEAMS), the Light Water Reactor Sustainability (LWRS), the Small Modular Reactors (SMR), and the Next Generation Nuclear Power Plant (NGNP) programs. These programs all involve computational modeling and simulation (M&S) of nuclear reactor systems, components and processes, and it is envisioned that NE-KAMS will help to coordinate and facilitate collaboration and sharing of resources and expertise for V&V and UQ across these programs. In addition, from the outset, NE-KAMS will support the use of computational M&S in the nuclear industry by developing guidelines and recommended practices aimed at quantifying the uncertainty and assessing the applicability of existing analysis models and methods. The NE-KAMS effort will initially focus on supporting the use of computational fluid dynamics (CFD) and thermal hydraulics (T/H) analysis for M&S of nuclear reactor systems, components and processes, and will later expand to include materials, fuel system performance and other areas of M&S as time and funding allow.

Rich Johnson; Kimberlyn C. Mousseau; Hyung Lee

2011-09-01

39

Advances in edge-diffraction modeling for virtual-acoustic simulations  

NASA Astrophysics Data System (ADS)

In recent years there has been growing interest in modeling sound propagation in complex, three-dimensional (3D) virtual environments. With diverse applications for the military, the gaming industry, psychoacoustics researchers, architectural acousticians, and others, advances in computing power and 3D audio-rendering techniques have driven research and development aimed at closing the gap between the auralization and visualization of virtual spaces. To this end, this thesis focuses on improving the physical and perceptual realism of sound-field simulations in virtual environments through advances in edge-diffraction modeling. To model sound propagation in virtual environments, acoustical simulation tools commonly rely on geometrical-acoustics (GA) techniques that assume asymptotically high frequencies, large flat surfaces, and infinitely thin ray-like propagation paths. Such techniques can be augmented with diffraction modeling to compensate for the effect of surface size on the strength and directivity of a reflection, to allow for propagation around obstacles and into shadow zones, and to maintain soundfield continuity across reflection and shadow boundaries. Using a time-domain, line-integral formulation of the Biot-Tolstoy-Medwin (BTM) diffraction expression, this thesis explores various aspects of diffraction calculations for virtual-acoustic simulations. Specifically, we first analyze the periodic singularity of the BTM integrand and describe the relationship between the singularities and higher-order reflections within wedges with open angle less than 180°. Coupled with analytical approximations for the BTM expression, this analysis allows for accurate numerical computations and a continuous sound field in the vicinity of an arbitrary wedge geometry insonified by a point source. Second, we describe an edge-subdivision strategy that allows for fast diffraction calculations with low error relative to a numerically more accurate solution. Third, to address the considerable increase in propagation paths due to diffraction, we describe a simple procedure for identifying and culling insignificant diffraction components during a virtual-acoustic simulation. Finally, we present a novel method to find GA components using diffraction parameters that ensures continuity at reflection and shadow boundaries.

Calamia, Paul Thomas

40

Advanced Fluid System Simulation.  

National Technical Information Service (NTIS)

The report describes the continued development and test verification of digital computer models used to simulate hydraulic systems under dynamic conditions. A hydraulic acoustic generator was built and tested for frequency response work. Pulsation attenua...

H. DeGarcia R. F. Deshazer R. J. Levek N. J. Pierce M. J. Stevens

1980-01-01

41

PSP: An Advanced Surface-Potential-Based MOSFET Model for Circuit Simulation  

Microsoft Academic Search

This paper describes the latest and most advanced surface-potential-based model jointly developed by The Pennsylvania State University and Philips. Specific topics include model structure, mobility and velocity saturation description, further development and verification of symmetric linearization method, recent advances in the computational techniques for the surface potential, modeling of gate tunneling current, inclusion of the retrograde impurity profile, and noise

Gennady Gildenblat; Xin Li; Weimin Wu; Hailing Wang; Amit Jha; Ronald van Langevelde; G. D. J. Smit; Andries J. Scholten; Dirk B. M. Klaassen

2006-01-01

42

The Nuclear Energy Advanced Modeling and Simulation Safeguards and Separations Reprocessing Plant Toolkit  

SciTech Connect

This report details the progress made in the development of the Reprocessing Plant Toolkit (RPTk) for the DOE Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. RPTk is an ongoing development effort intended to provide users with an extensible, integrated, and scalable software framework for the modeling and simulation of spent nuclear fuel reprocessing plants by enabling the insertion and coupling of user-developed physicochemical modules of variable fidelity. The NEAMS Safeguards and Separations IPSC (SafeSeps) and the Enabling Computational Technologies (ECT) supporting program element have partnered to release an initial version of the RPTk with a focus on software usability and utility. RPTk implements a data flow architecture that is the source of the system's extensibility and scalability. Data flows through physicochemical modules sequentially, with each module importing data, evolving it, and exporting the updated data to the next downstream module. This is accomplished through various architectural abstractions designed to give RPTk true plug-and-play capabilities. A simple application of this architecture, as well as RPTk data flow and evolution, is demonstrated in Section 6 with an application consisting of two coupled physicochemical modules. The remaining sections describe this ongoing work in full, from system vision and design inception to full implementation. Section 3 describes the relevant software development processes used by the RPTk development team. These processes allow the team to manage system complexity and ensure stakeholder satisfaction. This section also details the work done on the RPTk ``black box'' and ``white box'' models, with a special focus on the separation of concerns between the RPTk user interface and application runtime. Section 4 and 5 discuss that application runtime component in more detail, and describe the dependencies, behavior, and rigorous testing of its constituent components.

McCaskey, Alex [ORNL; Billings, Jay Jay [ORNL; de Almeida, Valmor F [ORNL

2011-08-01

43

ADVANCED UTILITY SIMULATION MODEL, MULTI-PERIOD MULTI-STATE MODULE DESIGN DOCUMENTATION (VERSION 1.0)  

EPA Science Inventory

The report is one of 11 in a series describing the initial development of the Advanced Utility Simulation Model (AUSM) by the Universities Research Group on Energy (URGE) and its continued development by the Science Applications International Corporation (SAIC) research team. The...

44

NEW CONCEPTS IN ESTABLISHMENT OF A COMMON TECHNICAL FRAMEWORK FOR MODELING AND SIMULATION AND ADVANCED DISTRIBUTED LEARNING  

Microsoft Academic Search

Modeling and simulation (M&S) and advanced distributed learning (ADL) will provide the Romanian Armed Forces (RAF) a readily available, flexible, and cost-effective means to support defense reform by fundamentally improving its operational, education and training, peacekeeping, and analytical capabilities. The \\

AUREL SERB

45

Recent advances in auxiliary-field methods --- simulations in lattice models and real materials  

NASA Astrophysics Data System (ADS)

We have developed an auxiliary-field (AF) quantum Monte Carlo (QMC) method for many-body simulations. The method takes the form of a linear superposition of independent-particle calculations in fluctuating external fields. ``Entanglement'' of the different field configurations leads to random walks in Slater determinant space. We formulate an approximate constraint on the random walk paths to control the sign/phase problem, which has shown to be very accurate even with simple mean-field solutions as the constraining trial wave function. The same method can be applied to both simplified lattice models and real materials. For realistic electronic Hamiltonians, each random walk stream resembles a density-functional theory (DFT) calculation in random local fields. Thus, the AF QMC method can directly import existing technology from standard electronic structure methods into a many-body QMC framework. We have demonstrated this method with calculations in close to 100 systems, including Si solid, first- and second-row molecular systems, molecules of heavier post-d elements, transition-metal systems, and ultra-cold atomic gases. In these we have operated largely in an automated mode, inputting the DFT or Hartree-Fock solutions as trial wave functions. The AF QMC results showed consistently good agreement with near-exact quantum chemistry results and/or experiment. I will also discuss additional algorithmic advances which can further improve the method in strongly correlated systems. Supported by ARO, NSF, ONR, and DOE-cmsn.

Zhang, Shiwei

2007-03-01

46

Experimental Research for Advanced Firefighting Simulators.  

National Technical Information Service (NTIS)

A phase I experimental modeling has been completed as part of NAVTRAEQUIPCEN task 7794, Advanced Firefighting Simulators. This consisted of application of a previously proposed synthetic technique to represent Class A, B and C Navy training fires by utili...

E. Swiatosz P. Grimmer

1978-01-01

47

Strategic Plan for Nuclear Energy -- Knowledge Base for Advanced Modeling and Simulation (NE-KAMS)  

Microsoft Academic Search

NE-KAMS knowledge base will assist computational analysts, physics model developers, experimentalists, nuclear reactor designers, and federal regulators by: (1) Establishing accepted standards, requirements and best practices for V&V and UQ of computational models and simulations, (2) Establishing accepted standards and procedures for qualifying and classifying experimental and numerical benchmark data, (3) Providing readily accessible databases for nuclear energy related experimental

Rich Johnson; Kimberlyn C. Mousseau; Hyung Lee

2011-01-01

48

Geophysical Simulations Conducted by the SEG Advanced Modeling Project (SEAM) for a Deepwater Subsalt Resource  

Microsoft Academic Search

Geophysical simulations are playing an increasingly large role in both predicting the future evolution of complex systems and for providing benchmark data to test new analysis approaches. As geophysical inversion schemes for determining model structure become increasingly sophisticated, and their ability to incorporate multiple types of geophysical data increases, there is need for challenging benchmark datasets to be used for

M. C. Fehler

2010-01-01

49

An Evaluation of Two Advanced Turbulence Models for Simulating the Flow and Dispersion Around Buildings  

SciTech Connect

Numerical modeling of airflow and pollutant dispersion around buildings is a challenging task due to the geometrical variations of buildings and the extremely complex flow created by such surface-mounted obstacles. The airflow around buildings inevitably involves impingement and separation regions, building wakes with multiple vortices, and jetting effects in street canyons. The interference from adjacent buildings further complicates the flow and dispersion patterns. Thus accurate simulations of building-scale transport phenomena requires not only appropriate physics submodels but also significant computing resources. They have developed an efficient, high resolution CFD model for simulating chemical and biological releases around buildings. The primary goal is to support incident response and preparedness in emergency response planning and vulnerability analysis.

Chan, S.T.; Stevens, D.E.

2000-03-14

50

Numerical Simulation of Earth Directed CMEs with an Advanced Two-Temperature Coronal Model (Invited)  

NASA Astrophysics Data System (ADS)

We present progress on modeling Earth-directed CMEs including the December 12, 2008 CME and the May 13, 2005 campaign event from initiation to heliospheric propagation. Our earlier work on the 2005 event followed the CME to the orbit of Saturn employing the coronal model of Cohen et al. (2007), which relies on a spatially varying adiabatic index (gamma) to produce the bimodal solar wind. This model was able to reproduce several features of the observed event, but suffered from artifacts of the artificially thermodynamics. We will examine results of a recent simulation performed with a new two-temperature solar corona model developed at the University of Michigan. This model employs heat conduction for both ion and electron species, constant adiabatic index (=5/3), and includes Alfven waves to drive the solar wind. The model includes SOHO/MDI magnetogram data to calculate the coronal field, and also uses SOHO/EIT observations to specify the density and temperature at the coronal boundary by the Differential Emission Measure Tomography (DEMT) method. The Wang-Sheeley-Arge empirical model is used to determine the Alfven wave pressure necessary to produce the observed solar wind speeds. We find that the new model is much better able to reproduce the solar wind densities, and also correctly captures the compression at the CME-driven shock due to the fixed adiabatic index.

Manchester, W. B.; van der Holst, B.; Frazin, R. A.; Vasquez, A. M.; Toth, G.; Gombosi, T. I.

2010-12-01

51

Advanced Utility Simulation Model description of the national loop (Version 3. 0). Final report, July 1985-September 1987  

SciTech Connect

This report describes the national loop of the Advanced Utility Simulation Model (AUSM), simulating strategic planning in the electric-utility industry. Acting as a preprocessor to the second component of AUSM (the state model), the national loop simulates decisions about generating and scrubber capacity additions, fuel choices, and interstate electricity transfers. These decisions influence (and are influenced by) coal prices, providing a partial equilibrium model of the coal-electric utility market. Three modules comprise the national loop: the Multi-Period, Multi-State Module (MPMS), the National Coal Supply Module (NCSM), and the Coal Market Equilibrium Module (CMEM). Electric-utility decisions are made in the MPMS and coal demands calculated. These are passed to the NCSM where coal prices are calculated. After being checked for convergence (which signals achievement of equilibrium), prices are passed to the MPMS for re-simulation of coal demand. This process continues until equilibrium is achieved or until it is determined that no equilibrium exists. In general, the report contains all of the principal equations and operating concepts for the national loop.

Capone, R.L.; Jones, L.G.

1988-12-01

52

Software Framework for Advanced Power Plant Simulations  

Microsoft Academic Search

This report summarizes the work accomplished during the Phase II development effort of the Advanced Process Engineering Co-Simulator (APECS). The objective of the project is to develop the tools to efficiently combine high-fidelity computational fluid dynamics (CFD) models with process modeling software. During the course of the project, a robust integration controller was developed that can be used in any

John Widmann; Sorin Munteanu; Aseem Jain; Pankaj Gupta; Mark Moales; Erik Ferguson; Lewis Collins; David Sloan; Woodrow Fiveland; Yi-dong Lang; Larry Biegler; Michael Locke; Simon Lingard; Jay Yun

2010-01-01

53

An advanced object-based software framework for complex ecosystem modeling and simulation  

SciTech Connect

Military land managers and decision makers face an ever increasing challenge to balance maximum flexibility for the mission with a diverse set of multiple land use, social, political, and economic goals. In addition, these goals encompass environmental requirements for maintaining ecosystem health and sustainability over the long term. Spatiotemporal modeling and simulation in support of adaptive ecosystem management can be best accomplished through a dynamic, integrated, and flexible approach that incorporates scientific and technological components into a comprehensive ecosystem modeling framework. The Integrated Dynamic Landscape Analysis and Modeling System (IDLAMS) integrates ecological models and decision support techniques through a geographic information system (GIS)-based backbone. Recently, an object-oriented (OO) architectural framework was developed for IDLAMS (OO-IDLAMS). This OO-IDLAMS Prototype was built upon and leverages from the Dynamic Information Architecture System (DIAS) developed by Argonne National Laboratory. DIAS is an object-based architectural framework that affords a more integrated, dynamic, and flexible approach to comprehensive ecosystem modeling than was possible with the GIS-based integration approach of the original IDLAMS. The flexibility, dynamics, and interoperability demonstrated through this case study of an object-oriented approach have the potential to provide key technology solutions for many of the military's multiple-use goals and needs for integrated natural resource planning and ecosystem management.

Sydelko, P. J.; Dolph, J. E.; Majerus, K. A.; Taxon, T. N.

2000-06-29

54

Advanced Vadose Zone Simulations Using TOUGH  

SciTech Connect

The vadose zone can be characterized as a complex subsurfacesystem in which intricate physical and biogeochemical processes occur inresponse to a variety of natural forcings and human activities. Thismakes it difficult to describe, understand, and predict the behavior ofthis specific subsurface system. The TOUGH nonisothermal multiphase flowsimulators are well-suited to perform advanced vadose zone studies. Theconceptual models underlying the TOUGH simulators are capable ofrepresenting features specific to the vadose zone, and of addressing avariety of coupled phenomena. Moreover, the simulators are integratedinto software tools that enable advanced data analysis, optimization, andsystem-level modeling. We discuss fundamental and computationalchallenges in simulating vadose zone processes, review recent advances inmodeling such systems, and demonstrate some capabilities of the TOUGHsuite of codes using illustrative examples.

Finsterle, S.; Doughty, C.; Kowalsky, M.B.; Moridis, G.J.; Pan,L.; Xu, T.; Zhang, Y.; Pruess, K.

2007-02-01

55

Nuclear Energy Advanced Modeling and Simulation (NEAMS) Waste Integrated Performance and Safety Codes (IPSC) : FY10 development and integration.  

SciTech Connect

This report describes the progress in fiscal year 2010 in developing the Waste Integrated Performance and Safety Codes (IPSC) in support of the U.S. Department of Energy (DOE) Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign. The goal of the Waste IPSC is to develop an integrated suite of computational modeling and simulation capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive waste storage or disposal system. The Waste IPSC will provide this simulation capability (1) for a range of disposal concepts, waste form types, engineered repository designs, and geologic settings, (2) for a range of time scales and distances, (3) with appropriate consideration of the inherent uncertainties, and (4) in accordance with robust verification, validation, and software quality requirements. Waste IPSC activities in fiscal year 2010 focused on specifying a challenge problem to demonstrate proof of concept, developing a verification and validation plan, and performing an initial gap analyses to identify candidate codes and tools to support the development and integration of the Waste IPSC. The current Waste IPSC strategy is to acquire and integrate the necessary Waste IPSC capabilities wherever feasible, and develop only those capabilities that cannot be acquired or suitably integrated, verified, or validated. This year-end progress report documents the FY10 status of acquisition, development, and integration of thermal-hydrologic-chemical-mechanical (THCM) code capabilities, frameworks, and enabling tools and infrastructure.

Criscenti, Louise Jacqueline; Sassani, David Carl; Arguello, Jose Guadalupe, Jr.; Dewers, Thomas A.; Bouchard, Julie F.; Edwards, Harold Carter; Freeze, Geoffrey A.; Wang, Yifeng; Schultz, Peter Andrew

2011-02-01

56

Advanced concepts flight simulation facility.  

PubMed

The cockpit environment is changing rapidly. New technology allows airborne computerised information, flight automation and data transfer with the ground. By 1995, not only will the pilot's task have changed, but also the tools for doing that task. To provide knowledge and direction for these changes, the National Aeronautics and Space Administration (NASA) and the Lockheed-Georgia Company have completed three identical Advanced Concepts Flight Simulation Facilities. Many advanced features have been incorporated into the simulators - e g, cathode ray tube (CRT) displays of flight and systems information operated via touch-screen or voice, print-outs of clearances, cockpit traffic displays, current databases containing navigational charts, weather and flight plan information, and fuel-efficient autopilot control from take-off to touchdown. More importantly, this cockpit is a versatile test bed for studying displays, controls, procedures and crew management in a full-mission context. The facility also has an air traffic control simulation, with radio and data communications, and an outside visual scene with variable weather conditions. These provide a veridical flight environment to evaluate accurately advanced concepts in flight stations. PMID:15676591

Chappell, S L; Sexton, G A

1986-12-01

57

Advances in direct numerical simulation for MHD modeling of free surface flows  

Microsoft Academic Search

The utilization of FLiBe (LiF?BeF2) free-surface flow as a chamber protection scheme is considered in advanced nuclear fusion reactor. At the design of the nuclear fusion reactor from the viewpoint of thermofluid research, it would be very important to understand the influence of a magnetic field in turbulent free surface flow. On the other hand, turbulent free surface flow (called

Shin-ichi Satake; Tomoaki Kunugi; Sergey Smolentsev

2002-01-01

58

Challenge problem and milestones for : Nuclear Energy Advanced Modeling and Simulation (NEAMS) waste Integrated Performance and Safety Codes (IPSC).  

SciTech Connect

This report describes the specification of a challenge problem and associated challenge milestones for the Waste Integrated Performance and Safety Codes (IPSC) supporting the U.S. Department of Energy (DOE) Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign. The NEAMS challenge problems are designed to demonstrate proof of concept and progress towards IPSC goals. The goal of the Waste IPSC is to develop an integrated suite of modeling and simulation capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive waste storage or disposal system. The Waste IPSC will provide this simulation capability (1) for a range of disposal concepts, waste form types, engineered repository designs, and geologic settings, (2) for a range of time scales and distances, (3) with appropriate consideration of the inherent uncertainties, and (4) in accordance with robust verification, validation, and software quality requirements. To demonstrate proof of concept and progress towards these goals and requirements, a Waste IPSC challenge problem is specified that includes coupled thermal-hydrologic-chemical-mechanical (THCM) processes that describe (1) the degradation of a borosilicate glass waste form and the corresponding mobilization of radionuclides (i.e., the processes that produce the radionuclide source term), (2) the associated near-field physical and chemical environment for waste emplacement within a salt formation, and (3) radionuclide transport in the near field (i.e., through the engineered components - waste form, waste package, and backfill - and the immediately adjacent salt). The initial details of a set of challenge milestones that collectively comprise the full challenge problem are also specified.

Freeze, Geoffrey A.; Wang, Yifeng; Howard, Robert; McNeish, Jerry A.; Schultz, Peter Andrew; Arguello, Jose Guadalupe, Jr.

2010-09-01

59

Recent advances in auxiliary-field methods --- simulations in lattice models and real materials  

Microsoft Academic Search

We have developed an auxiliary-field (AF) quantum Monte Carlo (QMC) method for many-body simulations. The method takes the form of a linear superposition of independent-particle calculations in fluctuating external fields. ``Entanglement'' of the different field configurations leads to random walks in Slater determinant space. We formulate an approximate constraint on the random walk paths to control the sign\\/phase problem, which

Shiwei Zhang

2007-01-01

60

Recent Advances in Simulation of Dendritic Polymers  

SciTech Connect

Dendrimers and hyperbranched polymers represent a revolution in methodology for directed synthesis of monodisperse polymers with enormous possibility of novel architectures. They demonstrate the ability to attain micelle-like structures with distinct internal and external character. Furthermore, the polyfunctional character of dendrimers allows varied response to environment and promise as selective sensors, carrier for drugs, encapsulation of toxic chemicals and metals. One of the key problems is the characterization of the structures. Theory and simulation can be essential to provide and predict structure and properties. We present some recent advances in theory, modeling and simulation of dendritic polymers.

Cagin, Tahir; Miklis, Paul J.; Wang, Guofeng; Zamanakos, Georgios; Martin, Ryan; Li, Hao; Mainz, Daniel T.; Nagarajan, V.; Goddard, William A.

1999-05-11

61

Cavity control system advanced modeling and simulations for TESLA linear accelerator and free electron laser  

NASA Astrophysics Data System (ADS)

The cavity control system for the TESLA -- TeV-Energy Superconducting Linear Accelerator project is initially introduced. The elementary analysis of the cavity resonator on RF (radio frequency) level and low level frequency with signal and power considerations is presented. For the field vector detection the digital signal processing is proposed. The electromechanical model concerning Lorentz force detuning is applied for analyzing the basic features of the system performance. For multiple cavities driven by one klystron the field vector sum control is considered. Simulink model implementation is developed to explore the feedback and feed-forward system operation and some experimental results for signals and power considerations are presented.

Czarski, Tomasz; Romaniuk, Ryszard S.; Pozniak, Krzysztof T.; Simrock, Stefan

2004-07-01

62

WARPM Framework for advanced plasma model simulations on many-core architectures  

NASA Astrophysics Data System (ADS)

A new framework WARPM designed for many-core computing architectures such as GPU is presented. The framework supports both multi-fluid and continuum kinetic plasma models. We provide exemplary physics results including whistler wave propagation, and show performance gains. For good performance on many-core architectures, code design should minimize data movement. The algorithms developed are thus both local and explicit. Fluid and continuum kinetic models on structured grids also benefit from predictable data access patterns as opposed to PIC models. The resulting framework is a hybrid combination of MPI for communication between nodes, threads for task parallelism on each node, and OpenCL parallel numerical method implementation across hundreds of cores per node. The framework manages data movement, sub-domain sequencing, and I/O intelligently such that memory bandwidth bottlenecks can be significantly hidden. Use of OpenCL and our method for sequencing computation naturally allows for heterogeneous computation utilizing both CPU and GPU on a node. A new dynamic OpenCL code assembly scheme allows support for many different models, numerical methods, and geometries; a specific combination of these is chosen at runtime then used to generate a single compiled kernel.

Reddell, Noah; Shumlak, Uri

2012-10-01

63

Advanced simulations for hot forging: heat transfer model for use with the finite element method  

Microsoft Academic Search

In a companion paper, a friction model for isothermal forging is described. Extension to a general hot forging case requires consideration of heat transfer across the tooling\\/workpiece interface, since a chilling of the workpiece by the dies will have evolving material properties that can significantly affect the forging operation. This is a complicated problem, since the film thickness, surface roughness

William R. D. Wilson; Steven R. Schmid; Jiying Liu

2004-01-01

64

Cavity control system advanced modeling and simulations for TESLA linear accelerator and free electron laser  

Microsoft Academic Search

The cavity control system for the TESLA -- TeV-Energy Superconducting Linear Accelerator project is initially introduced. The elementary analysis of the cavity resonator on RF (radio frequency) level and low level frequency with signal and power considerations is presented. For the field vector detection the digital signal processing is proposed. The electromechanical model concerning Lorentz force detuning is applied for

Tomasz Czarski; Ryszard S. Romaniuk; Krzysztof T. Pozniak; Stefan Simrock

2004-01-01

65

Software Framework for Advanced Power Plant Simulations  

SciTech Connect

This report summarizes the work accomplished during the Phase II development effort of the Advanced Process Engineering Co-Simulator (APECS). The objective of the project is to develop the tools to efficiently combine high-fidelity computational fluid dynamics (CFD) models with process modeling software. During the course of the project, a robust integration controller was developed that can be used in any CAPE-OPEN compliant process modeling environment. The controller mediates the exchange of information between the process modeling software and the CFD software. Several approaches to reducing the time disparity between CFD simulations and process modeling have been investigated and implemented. These include enabling the CFD models to be run on a remote cluster and enabling multiple CFD models to be run simultaneously. Furthermore, computationally fast reduced-order models (ROMs) have been developed that can be 'trained' using the results from CFD simulations and then used directly within flowsheets. Unit operation models (both CFD and ROMs) can be uploaded to a model database and shared between multiple users.

John Widmann; Sorin Munteanu; Aseem Jain; Pankaj Gupta; Mark Moales; Erik Ferguson; Lewis Collins; David Sloan; Woodrow Fiveland; Yi-dong Lang; Larry Biegler; Michael Locke; Simon Lingard; Jay Yun

2010-08-01

66

Advanced Initiatives in Medical Simulation, 3rd Annual Conference to Create Awareness of Medical Simulation.  

National Technical Information Service (NTIS)

This report summarizes the presentations at the 3rd Annual Advanced Initiatives in Medical Simulation Conference. The conference title was 'Simulation in Health Care: A Model for Improving Patient Safety and Ensuring Quality.' The presentations were as fo...

J. Eder-Van Hook

2006-01-01

67

Modeling, Simulation and Analysis of Complex Networked Systems: A Program Plan for DOE Office of Advanced Scientific Computing Research  

SciTech Connect

Many complex systems of importance to the U.S. Department of Energy consist of networks of discrete components. Examples are cyber networks, such as the internet and local area networks over which nearly all DOE scientific, technical and administrative data must travel, the electric power grid, social networks whose behavior can drive energy demand, and biological networks such as genetic regulatory networks and metabolic networks. In spite of the importance of these complex networked systems to all aspects of DOE's operations, the scientific basis for understanding these systems lags seriously behind the strong foundations that exist for the 'physically-based' systems usually associated with DOE research programs that focus on such areas as climate modeling, fusion energy, high-energy and nuclear physics, nano-science, combustion, and astrophysics. DOE has a clear opportunity to develop a similarly strong scientific basis for understanding the structure and dynamics of networked systems by supporting a strong basic research program in this area. Such knowledge will provide a broad basis for, e.g., understanding and quantifying the efficacy of new security approaches for computer networks, improving the design of computer or communication networks to be more robust against failures or attacks, detecting potential catastrophic failure on the power grid and preventing or mitigating its effects, understanding how populations will respond to the availability of new energy sources or changes in energy policy, and detecting subtle vulnerabilities in large software systems to intentional attack. This white paper outlines plans for an aggressive new research program designed to accelerate the advancement of the scientific basis for complex networked systems of importance to the DOE. It will focus principally on four research areas: (1) understanding network structure, (2) understanding network dynamics, (3) predictive modeling and simulation for complex networked systems, and (4) design, situational awareness and control of complex networks. The program elements consist of a group of Complex Networked Systems Research Institutes (CNSRI), tightly coupled to an associated individual-investigator-based Complex Networked Systems Basic Research (CNSBR) program. The CNSRI's will be principally located at the DOE National Laboratories and are responsible for identifying research priorities, developing and maintaining a networked systems modeling and simulation software infrastructure, operating summer schools, workshops and conferences and coordinating with the CNSBR individual investigators. The CNSBR individual investigator projects will focus on specific challenges for networked systems. Relevancy of CNSBR research to DOE needs will be assured through the strong coupling provided between the CNSBR grants and the CNSRI's.

Brown, D L

2009-05-01

68

HiSIM: a drift-diffusion-based advanced MOSFET model for circuit simulation with easy parameter extraction  

Microsoft Academic Search

We present here the MOSFET model HiSIM (Hiroshima University Starc IGFET model). As HiSIM employs the drift-diffusion approximation and preserves correct modeling of the surface potential in the channel, it is not only accurate, but additionally, model parameter number is small, parameter interdependence is removed, and parameter extraction becomes easy. Measured current-voltage characteristics of advanced MOSFETs are thus reproduced with

M. Suetake; K. Suematsu; H. Nagakura; M. Miura-Mattausch; H. J. Mattausch; S. Kumashiro; T. Yamaguchi; S. Odanakaa; N. Nakayama

2000-01-01

69

ADVANCED CHEMISTRY BASINS MODEL  

Microsoft Academic Search

The advanced Chemistry Basin Model project has been operative for 48 months. During this period, about half the project tasks are on projected schedule. On average the project is somewhat behind schedule (90%). Unanticipated issues are causing model integration to take longer then scheduled, delaying final debugging and manual development. It is anticipated that a short extension will be required

William Goddard; Lawrence Cathles; Mario Blanco; Paul Manhardt; Peter Meulbroek; Yongchun Tang

2004-01-01

70

Patient-Specific Geometry Modeling and Mesh Generation for Simulating Obstructive Sleep Apnea Syndrome Cases by Maxillomandibular Advancement  

PubMed Central

The objective of this paper is the reconstruction of upper airway geometric models as hybrid meshes from clinically used Computed Tomography (CT) data sets in order to understand the dynamics and behaviors of the pre- and postoperative upper airway systems of Obstructive Sleep Apnea Syndrome (OSAS) patients by viscous Computational Fluid Dynamics (CFD) simulations. The selection criteria for OSAS cases studied are discussed because two reasonable pre- and postoperative upper airway models for CFD simulations may not be created for every case without a special protocol for CT scanning. The geometry extraction and manipulation methods are presented with technical barriers that must be overcome so that they can be used along with computational simulation software as a daily clinical evaluation tool. Eight cases are presented in this paper, and each case consists of pre- and postoperative configurations. The results of computational simulations of two cases are included in this paper as demonstration.

Ito, Yasushi; Cheng, Gary C.; Shih, Alan M.; Koomullil, Roy P.; Soni, Bharat K.; Sittitavornwong, Somsak; Waite, Peter D.

2011-01-01

71

A station blackout simulation for the Advanced Neutron Source Reactor using the integrated primary and secondary system model  

Microsoft Academic Search

The Advanced Neutron Source Reactor (ANSR) is a research reactor to be built at Oak Ridge National Laboratory. This paper deals with thermal-hydraulic analysis of ANSR`s cooling systems during nominal and transient conditions, with the major effort focusing upon the construction and testing of computer models of the reactor`s primary, secondary and reflector vessel cooling systems. The code RELAP5 was

1994-01-01

72

ADVANCED CHEMISTRY BASINS MODEL  

SciTech Connect

The advanced Chemistry Basin Model project has been operative for 48 months. During this period, about half the project tasks are on projected schedule. On average the project is somewhat behind schedule (90%). Unanticipated issues are causing model integration to take longer then scheduled, delaying final debugging and manual development. It is anticipated that a short extension will be required to fulfill all contract obligations.

William Goddard III; Lawrence Cathles III; Mario Blanco; Paul Manhardt; Peter Meulbroek; Yongchun Tang

2004-05-01

73

ELMy H-mode linear simulation with 3-field model on experimental advanced superconducting tokamak using BOUT++  

SciTech Connect

H-mode plasmas with ELM (edge localized mode) have been realized on experimental advanced superconducting tokamak (EAST) with 2.45 GHz low hybrid wave at P{sub LHW}{approx}1 MW in 2010. Data from EAST experiments including magnetic geometry, measured pressure profiles, and calculated current profiles are used to investigate the physics of ELM utilizing the BOUT++ code. Results from linear simulations show that the ELMs in EAST are dominated by resistive ballooning modes. When the Lundquist number (dimensionless ratio of the resistive diffusion time to the Alfven time) is equal to or less than 10{sup 7}, the resistive ballooning modes are found to become unstable in the ELMy H-mode plasma. For a fixed pedestal pressure profile, increasing plasma current generates more activities of low-n ELMs.

Liu, Z. X.; Gao, X.; Liu, S. C.; Ding, S. Y.; Li, J. G. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Xia, T. Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Xu, X. Q. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Hughes, J. W. [Massachusetts Institute of Technology, Plasma Science and Fusion Center, 175 Albany Street, Cambridge, Massachusetts 02139 (United States)

2012-10-15

74

Models, Traffic Models, Simulation, and Traffic Simulation  

Microsoft Academic Search

\\u000a This introductory chapter to a book on traffic simulation fundamentals is aimed at setting up a comprehensive framework for\\u000a simulation as a well-established and grounded OR technique and its specificities when applied to traffic systems; the main\\u000a approaches to traffic simulation and the principles of traffic simulation model building; the fundamentals of traffic flow\\u000a theory and its application to traffic

Jaume Barceló

75

Advances in large eddy simulation methodology for complex flows  

Microsoft Academic Search

A review is provided of the recent advances in the derivation of the constitutive equations for large eddy simulation, subgrid scale modeling, wall modeling and applications of LES to turbulent combustion. The majority of the paper focuses on a review of two numerical methods for LES in complex geometry: the immersed boundary method and an unstructured mesh scheme. The latter

Parviz Moin

2002-01-01

76

Two-surface plasticity Model and Its Application to Spring-back Simulation of Automotive Advanced High Strength Steel Sheets  

NASA Astrophysics Data System (ADS)

A two-surface isotropic-kinematic hardening law was developed based on a two-surface plasticity model previously proposed by Lee et al., (2007, Int. J. Plast. 23, 1189-1212). In order to properly represent the Bauschinger and transient behaviors as well as permanent softening during reverse loading with various pre-strains, both the inner yield surface and the outer bounding surface expand (isotropic hardening) and translate (kinematic hardening) in this two-surface model. As for the permanent softening, both the isotropic hardening and the kinematic hardening evolution of the outer bounding surface were modified by introducing softening parameters. The numerical formulation was also developed based on the incremental plasticity theory and the developed constitutive law was implemented into the commercial finite element program, ABAQUS/Explicit and ABAQUS/Standard using the user-defined material subroutines. In this work, a dual phase (DP) steel was considered as an advanced high strength steel sheet and uni-axial tension tests and uni-axial tension-compression-tension tests were performed for the characterization of the material property. For a validation purpose, the developed two-surface plasticity model was applied to the 2-D draw bending test proposed as a benchmark problem of the NUMISHEET 2011 conference and successfully validated with experiments.

Park, Taejoon; Seok, Dong-Yoon; Lee, Chul-Hwan; Noma, Nobuyasu; Kuwabara, Toshihiko; Stoughton, Thomas B.; Chung, Kwansoo

2011-08-01

77

Joint modeling and simulation system  

NASA Astrophysics Data System (ADS)

The defense budget is shrinking. Weapon systems are getting more complex. Test requirements are increasing. The training and war gaming scenarios are getting more demanding as fielded systems and training simulators are integrated to support combined arms training. To cope with these requirements and still stay within the budget, the Department of Defense is relying on modeling and simulation. The state of the modeling and simulation (M&S) art has advanced to the point where a user can now create incredibly realistic, extremely detailed models which can augment test and evaluation, support the acquisition process, enhance training and war gaming, facilitate intelligence gathering, and support detailed engineering.

Boyer, Richard T.; McQuay, William K.

1993-08-01

78

Advancing Climate and Carbon Simulation.  

National Technical Information Service (NTIS)

We use a recently developed integrated climate/carbon model to perform breakthrough studies of the climate. Two major studies are carried out--namely the effects of CO(sub 2)-fertilized vegetation on global climate and carbon dynamics, and the effect of c...

S. Thompson

2004-01-01

79

Advanced deformation process modeling  

SciTech Connect

Progress was made in achieving a comprehensive and coherent description of material behavior in deformation processing. The materials included were metals, alloys, intermetallic compounds, arbitrary lattice structure, and metal matrix composites. Aspects of behavior modeled included kinetics of flow and strain hardening, as well as recrystallization and the various anisotropies of strength and compliance. Highlights include a new prediction of the limiting strength of materials at high temperature, a new understanding of the generation of new grain boundaries during forming operations, and a quantitatively verified computer simulation of texture development and the resulting behavioral anisotropies.

Kocks, U.F.; Embury, J.D. [Los Alamos National Lab., NM (United States); Beaudoin, A.J. [Reynolds Metals (United States); Dawson, P.R. [Cornell Univ., Ithaca, NY (United States); MacEwen, S.R. [Alcan (Canada); Mecking, H.J. [Hamburg Technic (Germany)

1997-08-01

80

An advanced physical model of cometary activity  

Microsoft Academic Search

We describe the present state of an advanced physical model aimed at the simulation of the environment of active cometary nuclei. The model can handle the complicated shapes of real cometary nuclei, and is ready to handle alternative assumptions concerning the nucleus composition and structure; its present version is based on the simple, but hitherto highly successful, Whipple (1950) paradigm:

A. V. Rodionov; J.-F. Crifo; K. Szego; J. Lagerros; M. Fulle

2002-01-01

81

A Virtual Engineering Framework for Simulating Advanced Power System  

Microsoft Academic Search

In this report is described the work effort performed to provide NETL with VE-Suite based Virtual Engineering software and enhanced equipment models to support NETL's Advanced Process Engineering Co-simulation (APECS) framework for advanced power generation systems. Enhancements to the software framework facilitated an important link between APECS and the virtual engineering capabilities provided by VE-Suite (e.g., equipment and process visualization,

Mike Bockelie; Dave Swensen; Martin Denison; Stanislav Borodai

2008-01-01

82

Advanced Production Planning Models  

SciTech Connect

>This report describes the innovative modeling approach developed as a result of a 3-year Laboratory Directed Research and Development project. The overall goal of this project was to provide an effective suite of solvers for advanced production planning at facilities in the nuclear weapons complex (NWC). We focused our development activities on problems related to operations at the DOE's Pantex Plant. These types of scheduling problems appear in many contexts other than Pantex--both within the NWC (e.g., Neutron Generators) and in other commercial manufacturing settings. We successfully developed an innovative and effective solution strategy for these types of problems. We have tested this approach on actual data from Pantex, and from Org. 14000 (Neutron Generator production). This report focuses on the mathematical representation of the modeling approach and presents three representative studies using Pantex data. Results associated with the Neutron Generator facility will be published in a subsequent SAND report. The approach to task-based scheduling described here represents a significant addition to the literature for large-scale, realistic scheduling problems in a variety of production settings.

JONES,DEAN A.; LAWTON,CRAIG R.; KJELDGAARD,EDWIN A.; WRIGHT,STEPHEN TROY; TURNQUIST,MARK A.; NOZICK,LINDA K.; LIST,GEORGE F.

2000-12-01

83

Advanced Chemistry Basins Model  

SciTech Connect

The DOE-funded Advanced Chemistry Basin model project is intended to develop a public domain, user-friendly basin modeling software under PC or low end workstation environment that predicts hydrocarbon generation, expulsion, migration and chemistry. The main features of the software are that it will: (1) afford users the most flexible way to choose or enter kinetic parameters for different maturity indicators; (2) afford users the most flexible way to choose or enter compositional kinetic parameters to predict hydrocarbon composition (e.g., gas/oil ratio (GOR), wax content, API gravity, etc.) at different kerogen maturities; (3) calculate the chemistry, fluxes and physical properties of all hydrocarbon phases (gas, liquid and solid) along the primary and secondary migration pathways of the basin and predict the location and intensity of phase fractionation, mixing, gas washing, etc.; and (4) predict the location and intensity of de-asphaltene processes. The project has be operative for 36 months, and is on schedule for a successful completion at the end of FY 2003.

William Goddard; Mario Blanco; Lawrence Cathles; Paul Manhardt; Peter Meulbroek; Yongchun Tang

2002-11-10

84

Advanced simulation of windmills in the electric power supply  

Microsoft Academic Search

An advanced model of a grid-connected windmill is set up where the windmill is a complex electro-mechanical system. The windmill model is implemented as a standardised component in the dynamic simulation tool, PSS\\/E, which makes it possible to investigate dynamic behaviour of grid-connected windmills as a part of realistic electrical grid models. This means an arbitrary number of wind farms

V. Akhmatov; H. Knudsen; A. H. Nielsen

2000-01-01

85

Reactive Potentials for Advanced Atomistic Simulations  

NASA Astrophysics Data System (ADS)

This article reviews recent advances in the development of reactive empirical force fields or potentials. In particular, we compare two widely used reactive potentials with variable-charge schemes that are desirable for multicomponent or multifunctional systems: the ReaxFF (reactive force field) and charge-optimized many-body (COMB) potentials. Several applications of these approaches in atomistic simulations that involve metal-based heterogeneous systems are also discussed.

Liang, Tao; Shin, Yun Kyung; Cheng, Yu-Ting; Yilmaz, Dundar E.; Vishnu, Karthik Guda; Verners, Osvalds; Zou, Chenyu; Phillpot, Simon R.; Sinnott, Susan B.; van Duin, Adri C. T.

2013-07-01

86

Using advanced simulation to aid microlithography development  

Microsoft Academic Search

An early historical overview is first presented here on the use of simulation in optical microlithography, along with a description of the general physical models. This paper then turns to more recent development work in microlithography simulation, which has followed several very different tracts. Three of the most important areas are discussed here. The first involves improvements in the underlying

DANIEL C. COLE; EYTAN BAROUCH; EDWARD W. CONRAD; MICHAEL YEUNG

2001-01-01

87

Advanced ST Plasma Scenario Simulations for NSTX  

SciTech Connect

Integrated scenario simulations are done for NSTX [National Spherical Torus Experiment] that address four primary milestones for developing advanced ST configurations: high {beta} and high {beta}{sub N} inductive discharges to study all aspects of ST physics in the high-beta regime; non-inductively sustained discharges for flattop times greater than the skin time to study the various current-drive techniques; non-inductively sustained discharges at high {beta} for flattop times much greater than a skin time which provides the integrated advanced ST target for NSTX; and non-solenoidal start-up and plasma current ramp-up. The simulations done here use the Tokamak Simulation Code (TSC) and are based on a discharge 109070. TRANSP analysis of the discharge provided the thermal diffusivities for electrons and ions, the neutral-beam (NB) deposition profile, and other characteristics. CURRAY is used to calculate the High Harmonic Fast Wave (HHFW) heating depositions and current drive. GENRAY/CQL3D is used to establish the heating and CD [current drive] deposition profiles for electron Bernstein waves (EBW). Analysis of the ideal-MHD stability is done with JSOLVER, BALMSC, and PEST2. The simulations indicate that the integrated advanced ST plasma is reachable, obtaining stable plasmas with {beta} {approx} 40% at {beta}{sub N}'s of 7.7-9, I{sub P} = 1.0 MA, and B{sub T} = 0.35 T. The plasma is 100% non-inductive and has a flattop of 4 skin times. The resulting global energy confinement corresponds to a multiplier of H{sub 98(y,2)} = 1.5. The simulations have demonstrated the importance of HHFW heating and CD, EBW off-axis CD, strong plasma shaping, density control, and early heating/H-mode transition for producing and optimizing these plasma configurations.

C.E. Kessel; E.J. Synakowski; D.A. Gates; R.W. Harvey; S.M. Kaye; T.K. Mau; J. Menard; C.K. Phillips; G. Taylor; R. Wilson; the NSTX Research Team

2004-10-28

88

Advanced ST plasma scenario simulations for NSTX  

NASA Astrophysics Data System (ADS)

Integrated scenario simulations are done for NSTX that address four primary objectives for developing advanced spherical torus (ST) configurations: high ? and high ?N inductive discharges to study all aspects of ST physics in the high ? regime; non-inductively sustained discharges for flattop times greater than the skin time to study the various current drive techniques; non-inductively sustained discharges at high ? for flattop times much greater than a skin time which provides the integrated advanced ST target for NSTX and non-solenoidal startup and plasma current rampup. The simulations done here use the tokamak simulation code and are based on a discharge 109070. TRANSP analysis of the discharge provided the thermal diffusivities for electrons and ions, the neutral beam deposition profile and other characteristics. CURRAY is used to calculate the high harmonic fast wave (HHFW) heating depositions and current drive. GENRAY/CQL3D is used to establish the heating and CD deposition profiles for electron Bernstein waves (EBW). Analysis of the ideal MHD stability is done with JSOLVER, BALMSC and PEST2. The simulations indicate that the integrated advanced ST plasma is reachable, obtaining stable plasmas with ?T ap 40% at ?N's of 7.7-9, IP = 1.0 MA and BT = 0.35 T. The plasma is 100% non-inductive and has a flattop of four skin times. The resulting global energy confinement corresponds to a multiplier of H98(y),2 = 1.5. The simulations have demonstrated the importance of HHFW heating and CD, EBW off-axis CD, strong plasma shaping, density control and early heating/H-mode transition for producing and optimizing these plasma configurations.

Kessel, C. E.; Synakowski, E. J.; Bell, M. E.; Gates, D. A.; Harvey, R. W.; Kaye, S. M.; Mau, T. K.; Menard, J.; Phillips, C. K.; Taylor, G.; Wilson, R.; NSTX Research Team

2005-08-01

89

Extendsim Advanced Techology: Discrete Rate Simulation  

Microsoft Academic Search

ExtendSim is used to model continuous, discrete event, discrete rate, and agent-based systems. This paper will focus on the ExtendSim discrete rate capabilities for modeling high-speed and rate based systems. Continuous, discrete event, and discrete rate simulation models will be compared.

David Krahl

2009-01-01

90

Advanced manufacturing of large-scale composite structures: process modeling, manufacturing simulations and massively parallel computing platforms  

Microsoft Academic Search

Newly emerging composite manufacturing processes, where there exist only limited industrial experience, demonstrate a definite need for process simulations to reduce the time and cost associated with the product and process developments. The physical and geometric complexity of the net-shape composite structural parts produced by resin transfer molding (RTM) lead to larger computational problem sizes and computational complexity demanding more

R. V. Mohan; K. K. Tamma; D. R. Shires; A. Mark

1998-01-01

91

Chemical Kinetic Modeling of Advanced Transportation Fuels  

SciTech Connect

Development of detailed chemical kinetic models for advanced petroleum-based and nonpetroleum based fuels is a difficult challenge because of the hundreds to thousands of different components in these fuels and because some of these fuels contain components that have not been considered in the past. It is important to develop detailed chemical kinetic models for these fuels since the models can be put into engine simulation codes used for optimizing engine design for maximum efficiency and minimal pollutant emissions. For example, these chemistry-enabled engine codes can be used to optimize combustion chamber shape and fuel injection timing. They also allow insight into how the composition of advanced petroleum-based and non-petroleum based fuels affect engine performance characteristics. Additionally, chemical kinetic models can be used separately to interpret important in-cylinder experimental data and gain insight into advanced engine combustion processes such as HCCI and lean burn engines. The objectives are: (1) Develop detailed chemical kinetic reaction models for components of advanced petroleum-based and non-petroleum based fuels. These fuels models include components from vegetable-oil-derived biodiesel, oil-sand derived fuel, alcohol fuels and other advanced bio-based and alternative fuels. (2) Develop detailed chemical kinetic reaction models for mixtures of non-petroleum and petroleum-based components to represent real fuels and lead to efficient reduced combustion models needed for engine modeling codes. (3) Characterize the role of fuel composition on efficiency and pollutant emissions from practical automotive engines.

PItz, W J; Westbrook, C K; Herbinet, O

2009-01-20

92

Nuclear Energy Advanced Modeling and Simulation (NEAMS) waste Integrated Performance and Safety Codes (IPSC) : gap analysis for high fidelity and performance assessment code development.  

SciTech Connect

This report describes a gap analysis performed in the process of developing the Waste Integrated Performance and Safety Codes (IPSC) in support of the U.S. Department of Energy (DOE) Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign. The goal of the Waste IPSC is to develop an integrated suite of computational modeling and simulation capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive waste storage or disposal system. The Waste IPSC will provide this simulation capability (1) for a range of disposal concepts, waste form types, engineered repository designs, and geologic settings, (2) for a range of time scales and distances, (3) with appropriate consideration of the inherent uncertainties, and (4) in accordance with rigorous verification, validation, and software quality requirements. The gap analyses documented in this report were are performed during an initial gap analysis to identify candidate codes and tools to support the development and integration of the Waste IPSC, and during follow-on activities that delved into more detailed assessments of the various codes that were acquired, studied, and tested. The current Waste IPSC strategy is to acquire and integrate the necessary Waste IPSC capabilities wherever feasible, and develop only those capabilities that cannot be acquired or suitably integrated, verified, or validated. The gap analysis indicates that significant capabilities may already exist in the existing THC codes although there is no single code able to fully account for all physical and chemical processes involved in a waste disposal system. Large gaps exist in modeling chemical processes and their couplings with other processes. The coupling of chemical processes with flow transport and mechanical deformation remains challenging. The data for extreme environments (e.g., for elevated temperature and high ionic strength media) that are needed for repository modeling are severely lacking. In addition, most of existing reactive transport codes were developed for non-radioactive contaminants, and they need to be adapted to account for radionuclide decay and in-growth. The accessibility to the source codes is generally limited. Because the problems of interest for the Waste IPSC are likely to result in relatively large computational models, a compact memory-usage footprint and a fast/robust solution procedure will be needed. A robust massively parallel processing (MPP) capability will also be required to provide reasonable turnaround times on the analyses that will be performed with the code. A performance assessment (PA) calculation for a waste disposal system generally requires a large number (hundreds to thousands) of model simulations to quantify the effect of model parameter uncertainties on the predicted repository performance. A set of codes for a PA calculation must be sufficiently robust and fast in terms of code execution. A PA system as a whole must be able to provide multiple alternative models for a specific set of physical/chemical processes, so that the users can choose various levels of modeling complexity based on their modeling needs. This requires PA codes, preferably, to be highly modularized. Most of the existing codes have difficulties meeting these requirements. Based on the gap analysis results, we have made the following recommendations for the code selection and code development for the NEAMS waste IPSC: (1) build fully coupled high-fidelity THCMBR codes using the existing SIERRA codes (e.g., ARIA and ADAGIO) and platform, (2) use DAKOTA to build an enhanced performance assessment system (EPAS), and build a modular code architecture and key code modules for performance assessments. The key chemical calculation modules will be built by expanding the existing CANTERA capabilities as well as by extracting useful components from other existing codes.

Lee, Joon H.; Siegel, Malcolm Dean; Arguello, Jose Guadalupe, Jr.; Webb, Stephen Walter; Dewers, Thomas A.; Mariner, Paul E.; Edwards, Harold Carter; Fuller, Timothy J.; Freeze, Geoffrey A.; Jove-Colon, Carlos F.; Wang, Yifeng

2011-03-01

93

Applications of Joint Tactical Simulation Modeling.  

National Technical Information Service (NTIS)

Advances in technology allow Computer Simulation Models (CSM) to be used as a powerful tool to aid military decision makers. This thesis explores the usefulness of one of these models, the Joint Tactical Simulation (JTS). First, this thesis outlines the i...

S. VanLandingham

1997-01-01

94

Modeling and simulation  

SciTech Connect

This book presents the papers given at a conference on computerized simulation. Topics considered at the conference included expert systems, modeling in electric power systems, power systems operating strategies, energy analysis, a linear programming approach to optimum load shedding in transmission systems, econometrics, simulation in natural gas engineering, solar energy studies, artificial intelligence, vision systems, hydrology, multiprocessors, and flow models.

Hanham, R.; Vogt, W.G.; Mickle, M.H.

1986-01-01

95

Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC) verification and validation plan. version 1.  

SciTech Connect

The objective of the U.S. Department of Energy Office of Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC) is to provide an integrated suite of computational modeling and simulation (M&S) capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive-waste storage facility or disposal repository. To meet this objective, NEAMS Waste IPSC M&S capabilities will be applied to challenging spatial domains, temporal domains, multiphysics couplings, and multiscale couplings. A strategic verification and validation (V&V) goal is to establish evidence-based metrics for the level of confidence in M&S codes and capabilities. Because it is economically impractical to apply the maximum V&V rigor to each and every M&S capability, M&S capabilities will be ranked for their impact on the performance assessments of various components of the repository systems. Those M&S capabilities with greater impact will require a greater level of confidence and a correspondingly greater investment in V&V. This report includes five major components: (1) a background summary of the NEAMS Waste IPSC to emphasize M&S challenges; (2) the conceptual foundation for verification, validation, and confidence assessment of NEAMS Waste IPSC M&S capabilities; (3) specifications for the planned verification, validation, and confidence-assessment practices; (4) specifications for the planned evidence information management system; and (5) a path forward for the incremental implementation of this V&V plan.

Bartlett, Roscoe Ainsworth; Arguello, Jose Guadalupe, Jr.; Urbina, Angel; Bouchard, Julie F.; Edwards, Harold Carter; Freeze, Geoffrey A.; Knupp, Patrick Michael; Wang, Yifeng; Schultz, Peter Andrew; Howard, Robert (Oak Ridge National Laboratory, Oak Ridge, TN); McCornack, Marjorie Turner

2011-01-01

96

Advanced Restraint System Modeling.  

National Technical Information Service (NTIS)

The Articulated Total Body (ATB) model is currently being used by the AFAMRL to study the biomechanics of the pilot-seat ejection from an aircraft. The new ATB-II model presented in this report incorporates features developed since the original ATB model ...

F. E. Butler J. T. Fleck

1980-01-01

97

Modeling, Simulation and Games  

Microsoft Academic Search

Using modeling and simulation techniques in game development can look\\u000d\\u000a\\u0009back on a comparably long history, starting in the early 1970s. In\\u000d\\u000a\\u0009contrast to this long tradition of combining games and simulations,\\u000d\\u000a\\u0009it is usually not made explicit which kind of simulation is used,\\u000d\\u000a\\u0009which models are fundament of the simulation, and which role the\\u000d\\u000a\\u0009simulation and the models have

Alke Martens; Jan Himmelspach; Roland Ewald

2008-01-01

98

THE PACKING SIMULATION MODEL  

Microsoft Academic Search

The Packing Simulation Model is a microcomputer application program designed for researchers, extension personnel, bankers, packing managers, or other specialists who plan the operations of a packing facility or simulate its financial performance. PACKSIM produces pro forma financial statements for packing facilities based on flexible crop mixes and packing assumptions. Variations can be made in the product harvest schedule, price,

Constance L. Falk; Daniel S. Tilley; Raymond Joe Schatzer

1987-01-01

99

Benchmark Dose Modeling - Advanced Topics  

EPA Science Inventory

Benchmark Dose ModelingAdvanced Topics Course The objectives of this full-day course are to provide participants with training on how to use the U.S. Environmental Protection Agency’s (EPA) Benchmark Dose Modeling Software (BMDS) and related software programs to fa...

100

Models and Simulations  

NSDL National Science Digital Library

Scientists use models and simulations to help them visualize, explain, and make predictions and hypotheses about the structures, properties, and behaviors of phenomena (e.g., objects, materials, processes, systems). The extremely small size and complexity

Krajcik, Joseph S.; Sutherland, Leeann M.; Stevens, Shawn Y.

2009-10-14

101

SHIPBUILDING ORGANIZATION SIMULATION MODELLING  

Microsoft Academic Search

System Dynamic Continuous Computer Simulation sub model of the Business-production Shipbuilding Process - PSBP, which building started during 1991\\/92, in the frame work of the global science project with title \\

Ante Munitic; Slavko Simundic; Josko Dvornik

102

Recent advances in superconducting-mixer simulations  

NASA Astrophysics Data System (ADS)

Over the last few years, considerable progress have been made in the development of techniques for fabricating high-quality superconducting circuits, and this success, together with major advances in the theoretical understanding of quantum detection and mixing at millimeter and submillimeter wavelengths, has made the development of CAD techniques for superconducting nonlinear circuits an important new enterprise. For example, arrays of quasioptical mixers are now being manufactured, where the antennas, matching networks, filters and superconducting tunnel junctions are all fabricated by depositing niobium and a variety of oxides on a single quartz substrate. There are no adjustable tuning elements on these integrated circuits, and therefore, one must be able to predict their electrical behavior precisely. This requirement, together with a general interest in the generic behavior of devices such as direct detectors and harmonic mixers, has lead us to develop a range of CAD tools for simulating the large-signal, small-signal, and noise behavior of superconducting tunnel junction circuits.

Withington, S.; Kennedy, P. R.

103

Advanced Chemistry Basins Model  

Microsoft Academic Search

The objective of this project is to: (1) Develop a database of additional and better maturity indicators for paleo-heat flow calibration; (2) Develop maturation models capable of predicting the chemical composition of hydrocarbons produced by a specific kerogen as a function of maturity, heating rate, etc.; assemble a compositional kinetic database of representative kerogens; (3) Develop a 4 phase equation

Mario Blanco; Lawrence Cathles; Paul Manhardt; Peter Meulbroek; Yongchun Tang

2003-01-01

104

Modeling Molecular Dynamics from Simulations  

SciTech Connect

Many important processes in biology occur at the molecular scale. A detailed understanding of these processes can lead to significant advances in the medical and life sciences. For example, many diseases are caused by protein aggregation or misfolding. One approach to studying these systems is to use physically-based computational simulations to model the interactions and movement of the molecules. While molecular simulations are computationally expensive, it is now possible to simulate many independent molecular dynamics trajectories in a parallel fashion by using super- or distributed- computing methods such as Folding@Home or Blue Gene. The analysis of these large, high-dimensional data sets presents new computational challenges. In this seminar, I will discuss a novel approach to analyzing large ensembles of molecular dynamics trajectories to generate a compact model of the dynamics. This model groups conformations into discrete states and describes the dynamics as Markovian, or history-independent, transitions between the states. I will discuss why the Markovian state model (MSM) is suitable for macromolecular dynamics, and how it can be used to answer many interesting and relevant questions about the molecular system. I will also discuss many of the computational and statistical challenges in building such a model, such as how to appropriately cluster conformations, determine the statistical reliability, and efficiently design new simulations.

Hinrichs, Nina Singhal (University of Chicago)

2009-01-28

105

Advances in high-resolution image simulation  

SciTech Connect

Continuing advances in hardware and software have improved both the speed and the range of computations that can be made to simulate high resolution electron microscope (HREM) images from various structures. Use of image display systems and array processors have made the image simulation procedure much more interactive while laser printers provide a fast high-quality hard copy output. Use of array processors has enabled the rewriting of electron scattering algorithms to include convergence effects (previously only considered after the scattered electron beams had emerged from the specimen) and upper-layer-line effects. With an array processor it is faster to compute effects of spatial and temporal coherence in real space, rather than use approximation solutions derived from series expansion in reciprocal space. With a frame buffer and suitable software the use has the facility to change parameters and view the results of the change almost immediately. Selected images can then be directed to hard copy output, in contrast with batch methods where series of hard copy images are produced and then selected from. Given a microdensitometer for input of experimental images from plates, or a video camera attached to the electron microscope and a frame buffer, split screen comparisons between experimental and computed images are possible, including independent control of image contrast, magnification and orientation. 23 refs., 19 figs., 2 tabs.

O'Keefe, M.A.; Kilaas, R.

1988-09-01

106

Oil market simulation model  

SciTech Connect

The Oil Market Simulation (OMS) model is a LOTUS 1-2-3 spread-sheet that simulates the world oil market. OMS is an annual model that projects the world oil market through the year 2000 from a data base that begins in 1979. The geographic coverage includes all market economies, with net imports from the centrally planned economies taken as an assumption. The model estimates the effects of price changes on oil supply and demand and computes an oil price path over time that allows supply and demand to remain in balance within the market economies area as a whole. 2 figs., 2 tabs.

Not Available

1989-06-01

107

AGRICULTURAL SIMULATION MODEL (AGSIM)  

EPA Science Inventory

AGSIM is a large-scale econometric simulation model of regional crop and national livestock production in the United States. The model was initially developed to analyze the aggregate economic impacts of a wide variety issues facing agriculture, such as technological change, pest...

108

Advancing the Art of Simulation in the Social Sciences  

Microsoft Academic Search

Advancing the state of the art of simulation in the social sciences requires appreciating the unique value of simulation as a third way of doing science, in contrast to both induction and deduction. Simulation can be an effective tool for discovering surprising consequences of simple assumptions. This essay offers advice for doing simulation research, focusing on the programming of a

Robert Axelrod

1997-01-01

109

Simulation models for schizophrenia  

Microsoft Academic Search

\\u000a As discussed in Ellenbroek and Cools, Animal models, this volume, the development of simulation models for schizophrenia has\\u000a gained momentum in the last decade through the recognition that not only symptoms, but also psychophysiological and psychological\\u000a disturbances of the disease can be used. This has led to the development of models like prepulse inhibition (PPI), P50 gating\\u000a and latent inhibition.

Bart A. Ellenbroek; Frank Sams-Dodd; Alexander R. Cools

110

Naval threat countermeasure simulator and the IR_CRUISE_missiles models for the generation of infrared (IR) videos of maritime targets and background for input into advanced imaging IR seekers  

NASA Astrophysics Data System (ADS)

A new hardware-in-the-loop modeling technique was developed at the US Naval Research Laboratory (NRL) for the evaluation of IR countermeasures against advanced IR imaging anti-ship cruise missiles. The research efforts involved the creation of tools to generate accurate IR imagery and synthesize video to inject in to real-world threat simulators. A validation study was conducted to verify the accuracy and limitations of the techniques that were developed.

Taczak, Thomas M.; Dries, John W.; Gover, Robert E.; Snapp, Mary Ann; Williams, Elmer F.; Cahill, Colin P.

2002-07-01

111

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS  

SciTech Connect

The recent Nevada Earthquake (M=6) produced an extraordinary set of crustal guided waves. In this study, we examine the three-component data at all the USArray stations in terms of how well existing models perform in predicting the various phases, Rayleigh waves, Love waves, and Pnl waves. To establish the source parameters, we applied the Cut and Paste Code up to distance of 5° for an average local crustal model which produced a normal mechanism (strike=35°,dip=41°,rake=-85°) at a depth of 9 km and Mw=5.9. Assuming this mechanism, we generated synthetics at all distances for a number of 1D and 3D models. The Pnl observations fit the synthetics for the simple models well both in timing (VPn=7.9km/s) and waveform fits out to a distance of about 5°. Beyond this distance a great deal of complexity can be seen to the northwest apparently caused by shallow subducted slab material. These paths require considerable crustal thinning and higher P-velocities. Small delays and advances outline the various tectonic province to the south, Colorado Plateau, etc. with velocities compatible with that reported on by Song et al.(1996). Five-second Rayleigh waves (Airy Phase) can be observed throughout the whole array and show a great deal of variation ( up to 30s). In general, the Love waves are better behaved than the Rayleigh waves. We are presently adding higher frequency to the source description by including source complexity. Preliminary inversions suggest rupture to northeast with a shallow asperity. We are, also, inverting the aftershocks to extend the frequencies to 2 Hz and beyond following the calibration method outlined in Tan and Helmberger (2007). This will allow accurate directivity measurements for events with magnitude larger than 3.5. Thus, we will address the energy decay with distance as s function of frequency band for the various source types.

Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

2008-04-15

112

A Virtual Engineering Framework for Simulating Advanced Power System  

SciTech Connect

In this report is described the work effort performed to provide NETL with VE-Suite based Virtual Engineering software and enhanced equipment models to support NETL's Advanced Process Engineering Co-simulation (APECS) framework for advanced power generation systems. Enhancements to the software framework facilitated an important link between APECS and the virtual engineering capabilities provided by VE-Suite (e.g., equipment and process visualization, information assimilation). Model enhancements focused on improving predictions for the performance of entrained flow coal gasifiers and important auxiliary equipment (e.g., Air Separation Units) used in coal gasification systems. In addition, a Reduced Order Model generation tool and software to provide a coupling between APECS/AspenPlus and the GE GateCycle simulation system were developed. CAPE-Open model interfaces were employed where needed. The improved simulation capability is demonstrated on selected test problems. As part of the project an Advisory Panel was formed to provide guidance on the issues on which to focus the work effort. The Advisory Panel included experts from industry and academics in gasification, CO2 capture issues, process simulation and representatives from technology developers and the electric utility industry. To optimize the benefit to NETL, REI coordinated its efforts with NETL and NETL funded projects at Iowa State University, Carnegie Mellon University and ANSYS/Fluent, Inc. The improved simulation capabilities incorporated into APECS will enable researchers and engineers to better understand the interactions of different equipment components, identify weaknesses and processes needing improvement and thereby allow more efficient, less expensive plants to be developed and brought on-line faster and in a more cost-effective manner. These enhancements to APECS represent an important step toward having a fully integrated environment for performing plant simulation and engineering. Furthermore, with little effort the modeling capabilities described in this report can be extended to support other DOE programs, such as ultra super critical boiler development, oxy-combustion boiler development or modifications to existing plants to include CO2 capture and sequestration.

Mike Bockelie; Dave Swensen; Martin Denison; Stanislav Borodai

2008-06-18

113

Discrete Event Simulation Model Decomposition.  

National Technical Information Service (NTIS)

Simulation models are currently being used for a multitude of purposes. Some simulation models are concise and well organized thereby facilitating their usage. However, some of these models may be quite lengthy and complex which causes development costs t...

S. R. Matthes

1988-01-01

114

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS  

SciTech Connect

High-Resolution Source Parameters using Calibration from Ambient Seismic Noise (ASN) Zhongwen Zhan, Shengji Wei, Sidao Ni, and Don V. Helmberger Abstract Several new methods have been developed to retrieve local Green's functions based on the cross-correlation of ambient seismic noise (station-to-station) and conventional (source-to-station) inversions. The latter methods provide the most broadband results but require accurate source parameters for phase-delay recovery which depends on the starting model. Considerable progress is being made in providing such information from 3D modeling, Tape et al. (2008), using Adjoint Tomography. But to match waveforms for the recent Chino Hills event still requires shifting synthetics to align on data. This means that it is difficult to use 3D simulations to refine source locations in near-real time. We can avoid the 3D problems by applying the CAP method and storing shifts from past events, Tan (2006), and/or using ASN, Shapiro et al. (2005), to predict lags for surface waves. Here, we directly compare results from CAP predictions with ASN results using stations near the Chino Hills event. We use the same SC seismic model as used in the Library of Earthquakes to generate Green's functions for noise (single force) for comparison with ASN correlations and allow Cap delays. We apply these delays or corrections to determine precise Centroid locations.

Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

2009-04-30

115

New Developments in the Simulation of Advanced Accelerator Concepts  

SciTech Connect

Improved computational methods are essential to the diverse and rapidly developing field of advanced accelerator concepts. We present an overview of some computational algorithms for laser-plasma concepts and high-brightness photocathode electron sources. In particular, we discuss algorithms for reduced laser-plasma models that can be orders of magnitude faster than their higher-fidelity counterparts, as well as important on-going efforts to include relevant additional physics that has been previously neglected. As an example of the former, we present 2D laser wakefield accelerator simulations in an optimal Lorentz frame, demonstrating >10 GeV energy gain of externally injected electrons over a 2 m interaction length, showing good agreement with predictions from scaled simulations and theory, with a speedup factor of {approx}2,000 as compared to standard particle-in-cell.

Bruhwiler, David L.; Cary, John R.; Cowan, Benjamin M.; Paul, Kevin; Mullowney, Paul J.; Messmer, Peter [Tech-X Corporation, Boulder, CO 80303 (United States); Geddes, Cameron G. R.; Esarey, Eric; Cormier-Michel, Estelle; Leemans, Wim; Vay, Jean-Luc [LOASIS program, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2009-01-22

116

New Developments in the Simulation of Advanced Accelerator Concepts  

SciTech Connect

Improved computational methods are essential to the diverse and rapidly developing field of advanced accelerator concepts. We present an overview of some computational algorithms for laser-plasma concepts and high-brightness photocathode electron sources. In particular, we discuss algorithms for reduced laser-plasma models that can be orders of magnitude faster than their higher-fidelity counterparts, as well as important on-going efforts to include relevant additional physics that has been previously neglected. As an example of the former, we present 2D laser wakefield accelerator simulations in an optimal Lorentz frame, demonstrating>10 GeV energy gain of externally injected electrons over a 2 m interaction length, showing good agreement with predictions from scaled simulations and theory, with a speedup factor of ~;;2,000 as compared to standard particle-in-cell.

Paul, K.; Cary, J.R.; Cowan, B.; Bruhwiler, D.L.; Geddes, C.G.R.; Mullowney, P.J.; Messmer, P.; Esarey, E.; Cormier-Michel, E.; Leemans, W.P.; Vay, J.-L.

2008-09-10

117

Agent-based Modeling and Simulation  

Microsoft Academic Search

Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of autonomous, interacting agents. Computational advances have made possible a growing number of agent-based models across a variety of application domains. Applications range from modeling agent behavior in the stock market, supply chains, and consumer markets, to predicting the spread of epidemics, mitigating the threat of bio-warfare,

Charles M. Macal; Michael J. North

2009-01-01

118

Simulation modeling using promodel technology: simulation modeling using promodel technology  

Microsoft Academic Search

PROMODEL's simulation modeling products are powerful yet easy-to-use simulation tools for modeling all types of systems and processes. ProModel® is designed to model manufacturing systems ranging from small job shops and machining cells to large mass production, flexible manufacturing systems, and supply chain systems. Other simulation products available from PROMODEL Corporation include MedModel®, ServiceModel®, and our latest release, ProModel PI

Charles R. Harrell; Rochelle N. Price

2003-01-01

119

Recent Improvements to an Advanced Atmospheric Transport Modeling System  

Microsoft Academic Search

The Atmospheric Technologies Group (ATG) has developed an advanced atmospheric modeling capability using the Regional Atmospheric Modeling System (RAMS) and a stochastic Lagrangian particle dispersion model (LPDM) for operational use at the Savannah River Site (SRS). For local simulations concerning releases from the Central Savannah River Area (CSRA), RAMS is run in a nested grid configuration with horizontal grid spacing

R. L. Buckley; C. H. Hunter

2005-01-01

120

Gyrokinetic particle simulation model  

SciTech Connect

A new type of particle simulation model based on the gyrophase-averaged Vlasov and Poisson equations is presented. The reduced system, in which particle gyrations are removed from the equations of motion while the finite Larmor radius effects are still preserved, is most suitable for studying low frequency microinstabilities in magnetized plasmas. It is feasible to simulate an elongated system (L/sub parallel/ >> L/sub perpendicular/) with a three-dimensional grid using the present model without resorting to the usual mode expansion technique, since there is essentially no restriction on the size of ..delta..x/sub parallel/ in a gyrokinetic plasma. The new approach also enables us to further separate the time and spatial scales of the simulation from those associated with global transport through the use of multiple spatial scale expansion. Thus, the model can be a very efficient tool for studying anomalous transport problems related to steady-state drift-wave turbulence in magnetic confinement devices. It can also be applied to other areas of plasma physics.

Lee, W.W.

1986-07-01

121

Revolutions in energy through modeling and simulation  

SciTech Connect

The development and application of energy technologies for all aspects from generation to storage have improved dramatically with the advent of advanced computational tools, particularly modeling and simulation. Modeling and simulation are not new to energy technology development, and have been used extensively ever since the first commercial computers were available. However, recent advances in computing power and access have broadened the extent and use, and, through increased fidelity (i.e., accuracy) of the models due to greatly enhanced computing power, the increased reliance on modeling and simulation has shifted the balance point between modeling and experimentation. The complex nature of energy technologies has motivated researchers to use these tools to understand better performance, reliability and cost issues related to energy. The tools originated in sciences such as the strength of materials (nuclear reactor containment vessels); physics, heat transfer and fluid flow (oil production); chemistry, physics, and electronics (photovoltaics); and geosciences and fluid flow (oil exploration and reservoir storage). Other tools include mathematics, such as statistics, for assessing project risks. This paper describes a few advancements made possible by these tools and explores the benefits and costs of their use, particularly as they relate to the acceleration of energy technology development. The computational complexity ranges from basic spreadsheets to complex numerical simulations using hardware ranging from personal computers (PCs) to Cray computers. In all cases, the benefits of using modeling and simulation relate to lower risks, accelerated technology development, or lower cost projects.

Tatro, M.; Woodard, J.

1998-08-01

122

Simulation modeling using PROMODEL technology  

Microsoft Academic Search

PROMODEL's simulation modeling products are powerful yet easy-to-use simulation tools for modeling all types of systems and processes. ProModel® is designed to model manufacturing systems ranging from small job shops and machining cells to large mass production, flexible manufacturing systems, and supply chain systems. Other simulation products available from PROMODEL Corporation include MedModel®, ServiceModel®, Innovate™, and ProModel PI™ (for process

C. R. Harrell; R. N. Price

2002-01-01

123

A discrete-event mesoscopic traffic simulation model for hybrid traffic simulation  

Microsoft Academic Search

The paper presents a mesoscopic traffic simulation model, particularly suited for the development of integrated meso-micro traffic simulation models. The model combines a number of the recent advances in simulation modeling, such as discrete-event time resolution and combined queue-server and speed-density modeling, with a number of new features such as the ability to integrate with microscopic models to create hybrid

Wilco Burghout; Haris N. Koutsopoulos; Ingmar Andreasson

2006-01-01

124

PRATHAM: Parallel Thermal Hydraulics Simulations using Advanced Mesoscopic Methods  

SciTech Connect

At the Oak Ridge National Laboratory, efforts are under way to develop a 3D, parallel LBM code called PRATHAM (PaRAllel Thermal Hydraulic simulations using Advanced Mesoscopic Methods) to demonstrate the accuracy and scalability of LBM for turbulent flow simulations in nuclear applications. The code has been developed using FORTRAN-90, and parallelized using the message passing interface MPI library. Silo library is used to compact and write the data files, and VisIt visualization software is used to post-process the simulation data in parallel. Both the single relaxation time (SRT) and multi relaxation time (MRT) LBM schemes have been implemented in PRATHAM. To capture turbulence without prohibitively increasing the grid resolution requirements, an LES approach [5] is adopted allowing large scale eddies to be numerically resolved while modeling the smaller (subgrid) eddies. In this work, a Smagorinsky model has been used, which modifies the fluid viscosity by an additional eddy viscosity depending on the magnitude of the rate-of-strain tensor. In LBM, this is achieved by locally varying the relaxation time of the fluid.

Joshi, Abhijit S [ORNL; Jain, Prashant K [ORNL; Mudrich, Jaime A [ORNL; Popov, Emilian L [ORNL

2012-01-01

125

Analyzing Advanced PDE Solvers Through Simulation  

Microsoft Academic Search

By simulating a real computer it is possible to gain a detailed knowl- edge of the cache memory utilization of an application, e.g., a partial differential equation (PDE) solver. Using this knowledge, we can discover regions with intri- cate cache memory performance. Furthermore, this information makes it possible to identify performance bottlenecks. In this paper, we employ full system simulation

Henrik Johansson; Dan Wallin; Sverker Holmgren

2004-01-01

126

Graphical simulation environments for modelling and simulation of integrative physiology.  

PubMed

Guyton's original integrative physiology model was a milestone in integrative physiology, combining significant physiological knowledge with an engineering perspective to develop a computational diagrammatic model. It is still used in research and teaching, with a small number of variants on the model also in circulation. However, though new research has added significantly to the knowledge represented by Guyton's model, and significant advances have been made in computing and simulation software, an accepted common platform to integrate this new knowledge has not emerged. This paper discusses the issues in the selection of a suitable platform, together with a number of current possibilities, and suggests a graphical computing environment for modelling and simulation. By way of example, a validated version of Guyton's 1992 model, implemented in the ubiquitous Simulink environment, is presented which provides a hierarchical representation amenable to extension and suitable for teaching and research uses. It is designed to appeal to the biomedical engineer and physiologist alike. PMID:20576310

Mangourova, Violeta; Ringwood, John; Van Vliet, Bruce

2010-06-23

127

Simulation modeling using ProModel technology  

Microsoft Academic Search

PROMODEL's simulation modeling products are powerful yet easy-to-use simulation tools for modeling all types of systems and processes. ProModel is designed to model manufacturing systems ranging from small job shops and machining cells to large mass production, flexible manufacturing systems, and supply chain systems. Other simulation products available from PROMODEL Corporation include MedModel®, ServiceModel®, and our latest release, ProModel PI

C. R. Harrell; R. N. Price

2003-01-01

128

Alignment and Initial Operation of an Advanced Solar Simulator.  

National Technical Information Service (NTIS)

A solar simulator utilizing nine 30-kW xenon arc lamps was built to provide radiant power for testing a solar dynamic space power system in a thermal vacuum environment. The advanced solar simulator achieved the following values specific to the solar dyna...

D. A. Jaworske K. S. Jefferies L. S. Mason

1996-01-01

129

UTILITY OF MECHANISTIC MODELS FOR DIRECTING ADVANCED SEPARATIONS RESEARCH & DEVELOPMENT ACTIVITIES: Electrochemically Modulated Separation Example  

SciTech Connect

The objective for this work was to demonstrate the utility of mechanistic computer models designed to simulate actinide behavior for use in efficiently and effectively directing advanced laboratory R&D activities associated with developing advanced separations methods.

Schwantes, Jon M.

2009-06-01

130

ADVANCED FAILURE MODES AND EFFECTS ANALYSIS USING BEHAVIOR MODELING  

Microsoft Academic Search

This paper presents a systematic method applicable at the early stages of design to enhance life-cycle quality of ownership: Advanced Failure Modes and Effect Analysis (AFMEA). The proposed method uses behavior modeling to simulate device operations and helps identify failure and customer dissatisfaction modes beyond component failures. The behavior model reasons about conditions that cause departures from normal operation and

Charles F. Eubanks; Steven Kmenta; Kosuke Ishii

1997-01-01

131

Advanced modeling of prompt fission neutrons  

SciTech Connect

Theoretical and numerical studies of prompt fission neutrons are presented. The main results of the Los Alamos model often used in nuclear data evaluation work are reviewed briefly, and a preliminary assessment of uncertainties associated with the evaluated prompt fission neutron spectrum for n (0.5 MeV)+{sup 239}Pu is discussed. Advanced modeling of prompt fission neutrons is done by Monte Carlo simulations of the evaporation process of the excited primary fission fragments. The successive emissions of neutrons are followed in the statistical formalism framework, and detailed information, beyond average quantities, can be inferred. This approach is applied to the following reactions: {sup 252}Cf (sf), n{sub th} + {sup 239}Pu, n (0.5 MeV)+{sup 235}U, and {sup 236}Pu (sf). A discussion on the merits and present limitations of this approach concludes this presentation.

Talou, Patrick [Los Alamos National Laboratory

2009-01-01

132

Advanced modeling of high intensity accelerators  

SciTech Connect

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goals of this project were three-fold: (1) to develop a new capability, based on high performance (parallel) computers, to perform large scale simulations of high intensity accelerators; (2) to apply this capability to modeling high intensity accelerators under design at LANL; and (3) to use this new capability to improve the understanding of the physics of intense charge particle beams, especially in regard to the issue of beam halo formation. All of these goals were met. In particular, the authors introduced split-operator methods as a powerful and efficient means to simulate intense beams in the presence of rapidly varying accelerating and focusing fields. They then applied these methods to develop scaleable, parallel beam dynamics codes for modeling intense beams in linacs, and in the process they implemented a new three-dimensional space charge algorithm. They also used the codes to study a number of beam dynamics issues related to the Accelerator Production of Tritium (APT) project, and in the process performed the largest simulations to date for any accelerator design project. Finally, they used the new modeling capability to provide direction and validation to beam physics studies, helping to identify beam mismatch as a major source of halo formation in high intensity accelerators. This LDRD project ultimately benefited not only LANL but also the US accelerator community since, by promoting expertise in high performance computing and advancing the state-of-the-art in accelerator simulation, its accomplishments helped lead to approval of a new DOE Grand Challenge in Computational Accelerator Physics.

Ryne, R.D.; Habib, S.; Wangler, T.P.

1998-11-01

133

PC-based Simulator for Education in Advanced Nuclear Power Plant Construction  

Microsoft Academic Search

The PC-based reactor simulation software PCTRAN was recently expanded to cover light water advanced reactors. The plant models include Generation III+ advanced PWR and BWR. The evolutionary designs are Areva EPR and GE ABWR by adding cooling path redundancy and devises for severe accident mitigation. One-step further is the passive-cooled Westinghouse AP1000 and GE ESBWR. Combined with PCTRAN's models of

Li-chi Cliff Po; Navajo Court

2008-01-01

134

Computational Cluster for Advanced Plasma Physics Simulations.  

National Technical Information Service (NTIS)

This DURIP equipment award was used to purchase, install, and bring on-line a computational cluster for plasma physics simulations. An SGI integrated cluster environment 'ICE' unit was purchased, featuring 192 2.8 GHz processors (on 24 nodes) with 384 GB ...

B. A. Nelson U. Shumlak

2010-01-01

135

Modeling and Simulation with INS.  

National Technical Information Service (NTIS)

INS, the Integrated Network Simulation language, puts simulation modeling into a network framework and automatically performs such programming activities as placing the problem into a next event structure, coding events, collecting statistics, monitoring ...

S. D. Roberts

1979-01-01

136

Advanced tokamak research with integrated modeling in JT-60 Upgrade  

Microsoft Academic Search

Researches on advanced tokamak (AT) have progressed with integrated modeling in JT-60 Upgrade [N. Oyama et al., Nucl. Fusion 49, 104007 (2009)]. Based on JT-60U experimental analyses and first principle simulations, new models were developed and integrated into core, rotation, edge\\/pedestal, and scrape-off-layer (SOL)\\/divertor codes. The integrated models clarified complex and autonomous features in AT. An integrated core model was

N. Hayashi

2010-01-01

137

Simulating CCDs for the Chandra Advanced CCD Imaging Spectrometer  

NASA Astrophysics Data System (ADS)

We have implemented a Monte Carlo algorithm to model and predict the response of various kinds of CCDs to X-ray photons and minimally ionizing particles and have applied this model to the CCDs in the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer. This algorithm draws on empirical results and predicts the response of all basic types of X-ray CCD devices. It relies on new solutions of the diffusion equation, including recombination, to predict the radial charge cloud distribution in field-free regions of CCDs. By adjusting the size of the charge clouds, we can reproduce the event grade distribution seen in calibration data. Using a model of the channel stops developed here and an insightful treatment of the insulating layer under the gate structure developed at MIT, we are able to reproduce all notable features in ACIS calibration spectra. The simulator is used to reproduce ground and flight calibration data from ACIS, thus confirming its fidelity. It can then be used for a variety of calibration tasks, such as generating spectral response matrices for spectral fitting of astrophysical sources, quantum efficiency estimation, and modeling of photon pile-up.

Townsley, L. K.; Broos, P. S.; Chartas, G.; Moskalenko, E.; Nousek, J. A.; Pavlov, G. G.

2002-07-01

138

Measurement and modeling of advanced coal conversion processes  

SciTech Connect

The overall objective of this program is the development of predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. This program will merge significant advances made in measuring and quantitatively describing the mechanisms in coal conversion behavior. Comprehensive computer codes for mechanistic modeling of entrained-bed gasification. Additional capabilities in predicting pollutant formation will be implemented and the technology will be expanded to fixed-bed reactors.

Solomon, P.R.; Serio, M.A.; Hamblen, D.G.; Smoot, L.D.; Brewster, B.S. (Advanced Fuel Research, Inc., East Hartford, CT (United States) Brigham Young Univ., Provo, UT (United States))

1991-01-01

139

Hydrocode modeling of advanced debris shield designs  

NASA Astrophysics Data System (ADS)

The NASA Johnson Space Center (JSC) Hypervelocity Impact Test Facility (HIT-F) has developed several low mass, high performance shielding concepts to protect spacecraft from orbital debris and meteoroid impact. Development testing requires shield concept validation in the impact velocity regime from <1 km/s to ~14.5 km/s. Current two-stage light gas gun testing limits maximum impact velocities to 8 km/s; therefore, Sandia National Laboratories and Southwest Research Institute have developed advanced launchers capable of accelerating non-spherical shaped masses to ~15 km/s. Since the shape of the impactor influences final rear wall damage, hydrocodes are employed to evaluate the so called shape effect at velocities greater than 8 km/s. A series of 14 hypervelocity impact simulations were conducted using the CTH hydrocode. Simulations modeled spherical aluminum (Al) and Al flat plate projectiles of various masses impacting double bumper all Al Whipple shields (DB). Experimental results at ~7 km/s are compared with simulation and ballistic limit curves are constructed for the DB Whipple shield in the velocity regime greater than 7 km/s. Comments are also made on the shape effect mass ratio for spherical and flat plate projectiles.

Kerr, J. H.; Christiansen, E. L.; Crews, J. L.

1996-05-01

140

Advances in thermal hydraulic and neutronic simulation for reactor analysis and safety  

SciTech Connect

This paper describes several large-scale computational models developed at Argonne National Laboratory for the simulation and analysis of thermal-hydraulic and neutronic events in nuclear reactors and nuclear power plants. The impact of advanced parallel computing technologies on these computational models is emphasized.

Tentner, A.M.; Blomquist, R.N.; Canfield, T.R.; Ewing, T.F.; Garner, P.L.; Gelbard, E.M.; Gross, K.C.; Minkoff, M.; Valentin, R.A.

1993-03-01

141

Software tool for advanced Monte Carlo simulation of electron scattering in EBL and SEM: CHARIOT  

Microsoft Academic Search

An advanced Monte Carlo model and software were developed to simulate electron scattering in electron beam lithography and signal formation in scanning electron microscopy at a new level of accuracy required for lithography and metrology. The model involves generation of fast secondary and slow secondary electrons, as well as generation of volume plasmons, and electron transfer between layers with regard

Sergey V. Babin; S. Borisov; E. Cheremukhin; Eugene Grachev; V. Korol; L. E. Ocola

2003-01-01

142

Development of an advanced transmission line fault location system; Part II- Algorithm development and simulation  

Microsoft Academic Search

This paper describes the solution techniques, system modeling considerations, and simulation studies performed as a part of the development of an advanced transmission line fault location system (AFLS) intended for use on the New York Power Authority's system. The Power Authority's Moses-Adirondack 230 kV lines were selected as a test bed for the study. A reduced model of the transmission

D. J. Lawrence; L. Z. Cabeza; L. T. Hochberg

1992-01-01

143

Dynamic Modeling and Simulation of a Switched Reluctance Motor in Electric Vehicles  

Microsoft Academic Search

Shareware softwares such as advanced vehicle simulator have extensively been used to simulate and design electric and hybrid vehicles. However, that software can only model the steady-state mode, and one can not see the dynamic performance of electric motors in the simulation. On the other hand, the switched reluctance motor model hasn't been seen in the advanced vehicle simulator software

S. Sadeghi; J. Milimonfared; M. Mirsalim; M. Jalalifar

2006-01-01

144

Modeling and Simulation of Electric and Hybrid Vehicles  

Microsoft Academic Search

This paper discusses the need for modeling and simulation of electric and hybrid vehicles. Different modeling methods such as physics-based Resistive Companion Form technique and Bond Graph method are presented with powertrain component and system modeling examples. The modeling and simulation capabilities of existing tools such as Powertrain System Analysis Toolkit (PSAT), ADvanced VehIcle SimulatOR (ADVISOR), PSIM, and Virtual Test

David Wenzhong Gao; Chris Mi; Ali Emadi

2007-01-01

145

The Wilsonville Advanced Coal Liquefaction Research and Development Facility, Wilsonville, Alabama: Development of a simulation model for bituminous coal liquefaction in the integrated process at Wilsonville: Topical report. [ASPEN  

SciTech Connect

The integrated two-stage liquefaction (ITSL) process was a major step in the coal liquefaction technology development. This process consists of a thermal liquefaction unit, a critical solvent deashing unit, and a catalytic hydrotreater in series. The system is integrated by the recycle of hydrotreated resid and solvent to the thermal liquefaction stage. Five ITSL runs were completed at the Advanced Coal Liquefaction R and D facility using Illinois No. 6 bituminous coal and Shell 324 nickel-molybdenum catalyst. This report presents a systematic development of a simulation model to predict the yield structure, stream flow rates, and stream compositions for Illinois No. 6 coal liquefaction in the ITSL configuration. Kinetic models will be presented for first-stage thermal reactions and second-stage hydrotreating reactions using data from a batch autoclave and the pilot plant runs. The applicability of ASPEN (Public) to predict high pressure and high temperature vapor-liquid equilibrium separations in the ITSL process will be shown by comparing the predicted data with the actual plant data. Unit models will be presented for the three units. Finally, these unit models will be integrated into an overall simulation model using ASPEN. 150 refs., 58 figs., 45 tabs.

Not Available

1987-08-01

146

Time parallelization of advanced operation scenario simulations of ITER plasma  

SciTech Connect

This work demonstrates that simulations of advanced burning plasma operation scenarios can be successfully parallelized in time using the parareal algorithm. CORSICA - an advanced operation scenario code for tokamak plasmas is used as a test case. This is a unique application since the parareal algorithm has so far been applied to relatively much simpler systems except for the case of turbulence. In the present application, a computational gain of an order of magnitude has been achieved which is extremely promising. A successful implementation of the Parareal algorithm to codes like CORSICA ushers in the possibility of time efficient simulations of ITER plasmas.

Samaddar, D. [ITER Organization, Saint Paul Lez Durance, France; Casper, T. A. [Lawrence Livermore National Laboratory (LLNL); Kim, S. H. [ITER Organization, Saint Paul Lez Durance, France; Berry, Lee A [ORNL; Elwasif, Wael R [ORNL; Batchelor, Donald B [ORNL; Houlberg, Wayne A [ORNL

2013-01-01

147

Verifying and validating simulation models  

Microsoft Academic Search

This paper discusses verification and validation of simulation models. The different approaches to deciding model validity am presented; how model verification and validation relate to the model development process are discussed; various validation techniques are defined, conceptual model validity, model verification, operational validity, and data validity are described; ways to document results are given; and a recommended procedure is presented.

Robert G. Sargent

1996-01-01

148

Analytical and Simulator Study of Advanced Transport.  

National Technical Information Service (NTIS)

An analytic methodology, based on the optimal-control pilot model, was demonstrated for assessing longitidunal-axis handling qualities of transport aircraft in final approach. Calibration of the methodology is largely in terms of closed-loop performance r...

W. H. Levison W. W. Rickard

1982-01-01

149

An Advanced Coarse-Grained Nucleosome Core Particle Model for Computer Simulations of Nucleosome-Nucleosome Interactions under Varying Ionic Conditions  

PubMed Central

In the eukaryotic cell nucleus, DNA exists as chromatin, a compact but dynamic complex with histone proteins. The first level of DNA organization is the linear array of nucleosome core particles (NCPs). The NCP is a well-defined complex of 147 bp DNA with an octamer of histones. Interactions between NCPs are of paramount importance for higher levels of chromatin compaction. The polyelectrolyte nature of the NCP implies that nucleosome-nucleosome interactions must exhibit a great influence from both the ionic environment as well as the positively charged and highly flexible N-terminal histone tails, protruding out from the NCP. The large size of the system precludes a modelling analysis of chromatin at an all-atom level and calls for coarse-grained approximations. Here, a model of the NCP that include the globular histone core and the flexible histone tails described by one particle per each amino acid and taking into account their net charge is proposed. DNA wrapped around the histone core was approximated at the level of two base pairs represented by one bead (bases and sugar) plus four beads of charged phosphate groups. Computer simulations, using a Langevin thermostat, in a dielectric continuum with explicit monovalent (K+), divalent (Mg2+) or trivalent (Co(NH3)63+) cations were performed for systems with one or ten NCPs. Increase of the counterion charge results in a switch from repulsive NCP-NCP interaction in the presence of K+, to partial aggregation with Mg2+ and to strong mutual attraction of all 10 NCPs in the presence of CoHex3+. The new model reproduced experimental results and the structure of the NCP-NCP contacts is in agreement with available data. Cation screening, ion-ion correlations and tail bridging contribute to the NCP-NCP attraction and the new NCP model accounts for these interactions.

Fan, Yanping; Korolev, Nikolay; Lyubartsev, Alexander P.; Nordenskiold, Lars

2013-01-01

150

Modeling and Simulation of Nuclear Fuel Materials  

SciTech Connect

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 ab initio to continuum levels. 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 defect 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.

Devanathan, Ramaswami; Van Brutzel, Laurent; Chartier, Alan; Gueneau, Christine; Mattsson, Ann E.; Tikare, Veena; Bartel, Timothy; Besmann, T. M.; Stan, Marius; Van Uffelen, Paul

2010-10-01

151

Modeling and Simulation of Nuclear Fuel Materials  

SciTech Connect

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 ab initio to continuum levels. Such an approach is essential to overcome the challenges posed by radioactive materials handling, experimental limitations in modeling extreme conditions and accident scenarios and small time and distance scales of fundamental defect 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.

Devanathan, Ram [Pacific Northwest National Laboratory (PNNL); Van Brutzel, Laurent [LSCE/CEA, Gif-sur-Yvette, France; Chartier, Alain [LSCE/CEA, Gif-sur-Yvette, France; Christine, Gueneau [LSCE/CEA, Gif-sur-Yvette, France; Mattsson, Ann [Sandia National Laboratories (SNL); Tikare, Veena [Sandia National Laboratories (SNL); Bartel, Timothy [Sandia National Laboratories (SNL); Besmann, Theodore M [ORNL; Stan, Marius [Los Alamos National Laboratory (LANL); Van Uffelen, Paul [Institute for Transuranium Elements, Germany

2010-01-01

152

Communications realism in C4ISR modeling and simulation in a distributed simulation environment  

Microsoft Academic Search

This paper describes a process for ensuring communications realism in army modeling and simulation (M&S). The applicability of the work spans research, development, and acquisition (RDA), advanced concepts requirements (ACR), and training, exercises, and military operations (TEMO), for constructive, virtual, and live simulations. The focus of the paper is on modeling of a high level architecture (HLA) compliant communications effects

Joseph Lacetera; Jon McConnell; John Roberts

1997-01-01

153

The advanced computational testing and simulation toolkit (ACTS)  

SciTech Connect

During the past decades there has been a continuous growth in the number of physical and societal problems that have been successfully studied and solved by means of computational modeling and simulation. Distinctively, a number of these are important scientific problems ranging in scale from the atomic to the cosmic. For example, ionization is a phenomenon as ubiquitous in modern society as the glow of fluorescent lights and the etching on silicon computer chips; but it was not until 1999 that researchers finally achieved a complete numerical solution to the simplest example of ionization, the collision of a hydrogen atom with an electron. On the opposite scale, cosmologists have long wondered whether the expansion of the Universe, which began with the Big Bang, would ever reverse itself, ending the Universe in a Big Crunch. In 2000, analysis of new measurements of the cosmic microwave background radiation showed that the geometry of the Universe is flat, and thus the Universe will continue expanding forever. Both of these discoveries depended on high performance computer simulations that utilized computational tools included in the Advanced Computational Testing and Simulation (ACTS) Toolkit. The ACTS Toolkit is an umbrella project that brought together a number of general purpose computational tool development projects funded and supported by the U.S. Department of Energy (DOE). These tools, which have been developed independently, mainly at DOE laboratories, make it easier for scientific code developers to write high performance applications for parallel computers. They tackle a number of computational issues that are common to a large number of scientific applications, mainly implementation of numerical algorithms, and support for code development, execution and optimization. The ACTS Toolkit Project enables the use of these tools by a much wider community of computational scientists, and promotes code portability, reusability, reduction of duplicate efforts, and tool maturity. This paper presents a brief introduction to the functionality available in ACTS.

Drummond, L.A.; Marques, O.

2002-05-21

154

Advanced Simulation and Computing National Code Strategy. Simulation-Based Complex Transformation.  

National Technical Information Service (NTIS)

The Integrated Codes (IC) program element plays a key role in the success of the Advanced Simulation and Computing (ASC) Campaign and the Science-Based Stockpile Stewardship Program (SSP). Stockpile stewardship encompasses a broad range of activities to e...

K. Alvin N. Frazier R. Mesiner

2009-01-01

155

Advanced computer simulation of pulverized fuel processes  

Microsoft Academic Search

Pulverized-fuel combustion is a complicated phenomenon which involves many subprocesses. The subprocesses which govern combustion include turbulent gas-phase chemistry and particle dispersion, radiant heat transmission, and fuel devolatilization\\/oxidation. A comprehensive numerical description of pulverized-fuel combustion necessitates an accurate description of these subprocesses. Earlier work done at Brigham Young University has led to the establishment of a comprehensive combustion model: PCGC-2.

J. D. Smith; A. Tsang

1989-01-01

156

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS  

SciTech Connect

Earthquake source parameters underpin several aspects of nuclear explosion monitoring. Such aspects are: calibration of moment magnitudes (including coda magnitudes) and magnitude and distance amplitude corrections (MDAC); source depths; discrimination by isotropic moment tensor components; and waveform modeling for structure (including waveform tomography). This project seeks to improve methods for and broaden the applicability of estimating source parameters from broadband waveforms using the Cut-and-Paste (CAP) methodology. The CAP method uses a library of Green’s functions for a one-dimensional (1D, depth-varying) seismic velocity model. The method separates the main arrivals of the regional waveform into 5 windows: Pnl (vertical and radial components), Rayleigh (vertical and radial components) and Love (transverse component). Source parameters are estimated by grid search over strike, dip, rake and depth and seismic moment or equivalently moment magnitude, MW, are adjusted to fit the amplitudes. Key to the CAP method is allowing the synthetic seismograms to shift in time relative to the data in order to account for path-propagation errors (delays) in the 1D seismic velocity model used to compute the Green’s functions. The CAP method has been shown to improve estimates of source parameters, especially when delay and amplitude biases are calibrated using high signal-to-noise data from moderate earthquakes, CAP+.

Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

2008-06-17

157

Advanced Simulation Capability for Environmental Management (ASCEM) Phase II Demonstration  

SciTech Connect

In 2009, the National Academies of Science (NAS) reviewed and validated the U.S. Department of Energy Office of Environmental Management (EM) Technology Program in its publication, Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges. The NAS report outlined prioritization needs for the Groundwater and Soil Remediation Roadmap, concluded that contaminant behavior in the subsurface is poorly understood, and recommended further research in this area as a high priority. To address this NAS concern, the EM Office of Site Restoration began supporting the development of the Advanced Simulation Capability for Environmental Management (ASCEM). ASCEM is a state-of-the-art scientific approach that uses an integration of toolsets for understanding and predicting contaminant fate and transport in natural and engineered systems. The ASCEM modeling toolset is modular and open source. It is divided into three thrust areas: Multi-Process High Performance Computing (HPC), Platform and Integrated Toolsets, and Site Applications. The ASCEM toolsets will facilitate integrated approaches to modeling and site characterization that enable robust and standardized assessments of performance and risk for EM cleanup and closure activities. During fiscal year 2012, the ASCEM project continued to make significant progress in capabilities development. Capability development occurred in both the Platform and Integrated Toolsets and Multi-Process HPC Simulator areas. The new Platform and Integrated Toolsets capabilities provide the user an interface and the tools necessary for end-to-end model development that includes conceptual model definition, data management for model input, model calibration and uncertainty analysis, and model output processing including visualization. The new HPC Simulator capabilities target increased functionality of process model representations, toolsets for interaction with the Platform, and model confidence testing and verification for quality assurance. The Platform and HPC capabilities are being tested and evaluated for EM applications through a suite of demonstrations being conducted by the Site Applications Thrust. In 2010, the Phase I Demonstration focused on testing initial ASCEM capabilities. The Phase II Demonstration, completed in September 2012, focused on showcasing integrated ASCEM capabilities. For Phase II, the Hanford Site Deep Vadose Zone (BC Cribs) served as an application site for an end-to-end demonstration of ASCEM capabilities on a site with relatively sparse data, with emphasis on integration and linkages between the Platform and HPC components. Other demonstrations included in this Phase II report included addressing attenuation-based remedies at the Savannah River Site F-Area, to exercise linked ASCEM components under data-dense and complex geochemical conditions, and conducting detailed simulations of a representative waste tank. This report includes descriptive examples developed by the Hanford Site Deep Vadose Zone, the SRS F-Area Attenuation-Based Remedies for the Subsurface, and the Waste Tank Performance Assessment working groups. The integrated Phase II Demonstration provides test cases to accompany distribution of the initial user release (Version 1.0) of the ASCEM software tools to a limited set of users in 2013. These test cases will be expanded with each new release, leading up to the release of a version that is qualified for regulatory applications in the 2015 time frame.?

Freshley, M.; Hubbard, S.; Flach, G.; Freedman, V.; Agarwal, D.; Andre, B.; Bott, Y.; Chen, X.; Davis, J.; Faybishenko, B.; Gorton, I.; Murray, C.; Moulton, D.; Meyer, J.; Rockhold, M.; Shoshani, A.; Steefel, C.; Wainwright, H.; Waichler, S.

2012-09-28

158

Software Requirements Specification Verifiable Fuel Cycle Simulation (VISION) Model  

SciTech Connect

The purpose of this Software Requirements Specification (SRS) is to define the top-level requirements for a Verifiable Fuel Cycle Simulation Model (VISION) of the Advanced Fuel Cycle (AFC). This simulation model is intended to serve a broad systems analysis and study tool applicable to work conducted as part of the AFCI (including costs estimates) and Generation IV reactor development studies.

D. E. Shropshire; W. H. West

2005-11-01

159

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS  

SciTech Connect

This quarter, we have focused on several tasks: (1) Building a high-quality catalog of earthquake source parameters for the Middle East and East Asia. In East Asia, we computed source parameters using the CAP method for a set of events studied by Herrman et al., (MRR, 2006) using a complete waveform technique. Results indicated excellent agreement with the moment magnitudes in the range 3.5 -5.5. Below magnitude 3.5 the scatter increases. For events with more than 2-3 observations at different azimuths, we found good agreement of focal mechanisms. Depths were generally consistent, although differences of up to 10 km were found. These results suggest that CAP modeling provides estimates of source parameters at least as reliable as complete waveform modeling techniques. However, East Asia and the Yellow Sea Korean Paraplatform (YSKP) region studied are relatively laterally homogeneous and may not benefit from the CAP method’s flexibility to shift waveform segments to account for path-dependent model errors. A more challenging region to study is the Middle East where strong variations in sedimentary basin, crustal thickness and crustal and mantle seismic velocities greatly impact regional wave propagation. We applied the CAP method to a set of events in and around Iran and found good agreement between estimated focal mechanisms and those reported by the Global Centroid Moment Tensor (CMT) catalog. We found a possible bias in the moment magnitudes that may be due to the thick low-velocity crust in the Iranian Plateau. (2) Testing Methods on a Lifetime Regional Data Set. In particular, the recent 2/21/08 Nevada Event and Aftershock Sequence occurred in the middle of USArray, producing over a thousand records per event. The tectonic setting is quite similar to Central Iran and thus provides an excellent testbed for CAP+ at ranges out to 10°, including extensive observations of crustal thinning and thickening and various Pnl complexities. Broadband modeling in 1D, 2D, and 3D will be presented. (3) Shallow Crustal Structure and Sparse Network Source Inversions for Southern California. We conducted a detailed test of a recently developed technique, CAPloc, in recovering source parameters including location and depth based on tomographic maps. We tested two-station solutions against 160 well determined events which worked well except for paths crossing deep basins and along mountain ridges.

Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

2008-10-17

160

Design and simulation of advanced charge recovery piezoactuator drivers  

NASA Astrophysics Data System (ADS)

The German Artificial Sphincter System project aims at the development of an implantable sphincter prosthesis driven by a piezoelectrically actuated micropump. The system has been designed to be fully implantable, i.e. the power supply is provided by a rechargeable lithium polymer battery. In order to provide sufficient battery duration and to limit battery dimensions, special effort has to be made to minimize power consumption of the whole system and, in particular, of the piezoactuator driver circuitry. Inductive charge recovery can be used to recover part of the charge stored within the actuator. We are going to present a simplified inductor-based circuit capable of voltage inversion across the actuator without the need of an additional negative voltage source. The dimension of the inductors required for such a concept is nevertheless significant. We therefore present a novel alternative concept, called direct switching, where the equivalent capacitance of the actuator is charged directly by a step-up converter and discharged by a step-down converter. We achieved superior performance compared to a simple inductor-based driver with the advantage of using small-size chip inductors. As a term of comparison, the performance of the aforementioned drivers is compared to a conventional driver that does not implement any charge recovery technique. With our design we have been able to achieve more than 50% reduction in power consumption compared to the simplest conventional driver. The new direct switching driver performs 15% better than an inductor-based driver. A novel, whole-system SPICE simulation is presented, where both the driving circuit and the piezoactuator are modeled making use of advanced nonlinear models. Such a simulation is a precious tool to design and optimize piezoactuator drivers.

Biancuzzi, G.; Lemke, T.; Woias, P.; Ruthmann, O.; Schrag, H. J.; Vodermayer, B.; Schmid, T.; Goldschmidtboeing, F.

2010-10-01

161

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS  

SciTech Connect

Abstract We conduct a detailed test of a recently developed technique, CAPloc, in recovering source parameters from a few stations against results from a large broadband network in Southern California. The method uses a library of 1D Green’s functions which are broken into segments and matched to waveform observations with adjustable timing shifts. These shifts can be established by calibration against a distribution of well-located earthquakes and assembled in tomographic images for predicting various phase-delays. Synthetics generated from 2D cross-sections through these models indicates that 1D synthetic waveforms are sufficient in modeling but simply shifted in time for most hard-rock sites. This simplification allows the source inversion for both mechanism and location to easily obtain by grid search. We test one-station mechanisms for 160 events against the array for both PAS and GSC which have data since 1960. While individual solutions work well (about 90%), joint solutions produce more reliable and defensible results. Inverting for both mechanism and location also works well except for certain complex paths across deep basins and along mountain ridges.

Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

2009-01-27

162

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS  

SciTech Connect

We conduct a detailed test of a recently developed technique, CAPloc, in recovering source parameters from a few stations against results from a large broadband network. The method uses a library of 1D Green’s functions which are broken into segments and matched to waveform observations with adjustable timing shifts. These shifts can be established by calibration against a distribution of well-located earthquake and assembled in tomographic images for predicting various phase-delays. Synthetics generated from 2D cross-sections through these models indicates that 1D synthetic waveforms are sufficient in modeling but simply shifted in time for hard-rock sites. This simplification allows the source inversion for both mechanism and location to be easily obtained by grid search. We test one-station mechanisms for 160 events against the array for both PAS and GSC which have data since 1960. While one station solutions work well (about 90%), joint solutions produce more reliable and defensible results. Inverting for both mechanism and location also works well except for certain difficult paths that cross deep basins or propagate along mountain ridges.

Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

2007-12-10

163

Numerical wind speed simulation model  

SciTech Connect

A relatively simple stochastic model for simulating wind speed time series that can be used as an alternative to time series from representative locations is described in this report. The model incorporates systematic seasonal variation of the mean wind, its standard deviation, and the correlation speeds. It also incorporates systematic diurnal variation of the mean speed and standard deviation. To demonstrate the model capabilities, simulations were made using model parameters derived from data collected at the Hanford Meteorology Station, and results of analysis of simulated and actual data were compared.

Ramsdell, J.V.; Athey, G.F.; Ballinger, M.Y.

1981-09-01

164

Advanced coal gasifier designs using large-scale simulations  

Microsoft Academic Search

Porting of the legacy code MFIX to a high performance computer (HPC) and the use of high resolution simulations for the design of a coal gasifier are described here. MFIX is based on a continuum multiphase flow model that considers gas and solids to form interpenetrating continua. Low resolution simulations of a commercial scale gasifier with a validated MFIX model

M. Syamlal; Chris Guenther; Aytekin Gel; Sreekanth Pannala

2009-01-01

165

Flight Dynamic Simulation Program in Air-Path Axes Using ACSL (Advanced Continuous Simulation Language).  

National Technical Information Service (NTIS)

The six degrees of freedom dynamic equations of motion have been programmed in the Advanced Continuous Simulation Language(ACSL) for use in aircraft simulations at ARL. Air-path axes were chosen for the integration of the force equations, and body axes fo...

P. W. Gibbens

1986-01-01

166

Validation of the Advanced Microphysics Prediction System (AMPS) using TRMM PR and TMI for KWAJEX simulations  

NASA Astrophysics Data System (ADS)

In this paper cloud microphysical variables simulated by the Advanced Microphysics Prediction System (AMPS) are validated against TRMM PR and TMI for tropical convective systems observed during KWAJEX. AMPS includes a unique ice microphysical framework called the Spectral Habit Ice Prediction System (SHIPS) to predict ice particle properties explicitly in a cloud resolving model (UW-NMS) (Hashino and Tripoli, 2007). For this study UW-NMS AMPS is set up for 2D simulation with periodic conditions over KWAJEX campaign area with synoptic forcing. In order to compare the model simulations, two instrumental simulators will be used. We will discuss the physical connections between the simulated cloud microphysical fields and microwave observations and identify pathways to improve the AMPS and the simulators.

Hashino, T.; Casella, D.; Mugnai, A.; Smith, E. A.; Tripoli, G. J.

2009-12-01

167

Software tool for advanced Monte Carlo simulation of electron scattering in EBL and SEM: CHARIOT  

NASA Astrophysics Data System (ADS)

An advanced Monte Carlo model and software were developed to simulate electron scattering in electron beam lithography and signal formation in scanning electron microscopy at a new level of accuracy required for lithography and metrology. The model involves generation of fast secondary and slow secondary electrons, as well as generation of volume plasmons, and electron transfer between layers with regard to the difference between work functions of layers. To track SEM detector channel, the geometry of a detector and its energy transfer function were taken into account. This advanced model was used to simulate electron trajectories, deposited energy, signal from electron detector and images in SEM. Examples of simulations are presented for electron spectra, energy deposition in 50 kV maskmaking, and signals from patterned wafers in SEM.

Babin, Sergey V.; Borisov, S.; Cheremukhin, E.; Grachev, Eugene; Korol, V.; Ocola, L. E.

2003-06-01

168

Lessons Learned From Dynamic Simulations of Advanced Fuel Cycles  

SciTech Connect

Years of performing dynamic simulations of advanced nuclear fuel cycle options provide insights into how they could work and how one might transition from the current once-through fuel cycle. This paper summarizes those insights from the context of the 2005 objectives and goals of the Advanced Fuel Cycle Initiative (AFCI). Our intent is not to compare options, assess options versus those objectives and goals, nor recommend changes to those objectives and goals. Rather, we organize what we have learned from dynamic simulations in the context of the AFCI objectives for waste management, proliferation resistance, uranium utilization, and economics. Thus, we do not merely describe “lessons learned” from dynamic simulations but attempt to answer the “so what” question by using this context. The analyses have been performed using the Verifiable Fuel Cycle Simulation of Nuclear Fuel Cycle Dynamics (VISION). We observe that the 2005 objectives and goals do not address many of the inherently dynamic discriminators among advanced fuel cycle options and transitions thereof.

Steven J. Piet; Brent W. Dixon; Jacob J. Jacobson; Gretchen E. Matthern; David E. Shropshire

2009-04-01

169

Numerical simulation of an advanced energy storage system using H 2O–LiBr as working fluid, Part 1: System design and modeling  

Microsoft Academic Search

The advanced energy storage technology proposed and patented by authors can be applied for cooling, heating, dehumidifying, combined cooling and heating, and so on. It is also called the variable mass energy transformation and storage (VMETS) technology in which the masses in one or two storage tanks change continuously during the energy charging and discharging processes. This paper presents an

S. M. Xu; L. Zhang; C. H. Xu; J. Liang; R. Du

2007-01-01

170

Nanorobot: Modelling and Simulation  

Microsoft Academic Search

This research addresses the state of the art in nanorobot design and simulation focusing on the leukemia disease as well as ongoing applications on addressing the challenges posed by cancer treatment, especially chemotherapy. Nanotechnology and cancer biology, along with a new concept to leukemia treatment are the basis for nanorobot design. Robot architecture consists of Body, Ultrasonic Sensors, Folate material

Arosha Senanayake; R. G. Sirisinghe; Phang Shih Mun

2007-01-01

171

Advanced Helmet Mounted Display (AHMD) for simulator applications  

NASA Astrophysics Data System (ADS)

The Advanced Helmet Mounted Display (AHMD), augmented reality visual system first presented at last year's Cockpit and Future Displays for Defense and Security conference, has now been evaluated in a number of military simulator applications and by L-3 Link Simulation and Training. This paper presents the preliminary results of these evaluations and describes current and future simulator and training applications for HMD technology. The AHMD blends computer-generated data (symbology, synthetic imagery, enhanced imagery) with the actual and simulated visible environment. The AHMD is designed specifically for highly mobile deployable, minimum resource demanding reconfigurable virtual training systems to satisfy the military's in-theater warrior readiness objective. A description of the innovative AHMD system and future enhancements will be discussed.

Sisodia, Ashok; Riser, Andrew; Bayer, Michael; McGuire, James P.

2006-06-01

172

Computer Model of an Advanced Dehumidifier.  

National Technical Information Service (NTIS)

An advanced dehumidifier, comprising a conventional heat pump dehumidifier modified by the addition of an air to air counterflow heat exchanger, was mathematically modelled on a digital computer. This report details the methods and assumptions used in the...

C. J. Blundell

1979-01-01

173

Progress in modeling and simulation.  

PubMed

For the modeling of systems, the computers are more and more used while the other "media" (including the human intellect) carrying the models are abandoned. For the modeling of knowledges, i.e. of more or less general concepts (possibly used to model systems composed of instances of such concepts), the object-oriented programming is nowadays widely used. For the modeling of processes existing and developing in the time, computer simulation is used, the results of which are often presented by means of animation (graphical pictures moving and changing in time). Unfortunately, the object-oriented programming tools are commonly not designed to be of a great use for simulation while the programming tools for simulation do not enable their users to apply the advantages of the object-oriented programming. Nevertheless, there are exclusions enabling to use general concepts represented at a computer, for constructing simulation models and for their easy modification. They are described in the present paper, together with true definitions of modeling, simulation and object-oriented programming (including cases that do not satisfy the definitions but are dangerous to introduce misunderstanding), an outline of their applications and of their further development. In relation to the fact that computing systems are being introduced to be control components into a large spectrum of (technological, social and biological) systems, the attention is oriented to models of systems containing modeling components. PMID:10803299

Kindler, E

1998-01-01

174

Genome Reshuffling for Advanced Intercross Permutation (GRAIP): Simulation and Permutation for Advanced Intercross Population Analysis  

PubMed Central

Background Advanced intercross lines (AIL) are segregating populations created using a multi-generation breeding protocol for fine mapping complex trait loci (QTL) in mice and other organisms. Applying QTL mapping methods for intercross and backcross populations, often followed by naïve permutation of individuals and phenotypes, does not account for the effect of AIL family structure in which final generations have been expanded and leads to inappropriately low significance thresholds. The critical problem with naïve mapping approaches in AIL populations is that the individual is not an exchangeable unit. Methodology/Principal Findings The effect of family structure has immediate implications for the optimal AIL creation (many crosses, few animals per cross, and population expansion before the final generation) and we discuss these and the utility of AIL populations for QTL fine mapping. We also describe Genome Reshuffling for Advanced Intercross Permutation, (GRAIP) a method for analyzing AIL data that accounts for family structure. GRAIP permutes a more interchangeable unit in the final generation crosses – the parental genome – and simulating regeneration of a permuted AIL population based on exchanged parental identities. GRAIP determines appropriate genome-wide significance thresholds and locus-specific P-values for AILs and other populations with similar family structures. We contrast GRAIP with naïve permutation using a large densely genotyped mouse AIL population (1333 individuals from 32 crosses). A naïve permutation using coat color as a model phenotype demonstrates high false-positive locus identification and uncertain significance levels, which are corrected using GRAIP. GRAIP also detects an established hippocampus weight locus and a new locus, Hipp9a. Conclusions and Significance GRAIP determines appropriate genome-wide significance thresholds and locus-specific P-values for AILs and other populations with similar family structures. The effect of family structure has immediate implications for the optimal AIL creation and we discuss these and the utility of AIL populations.

Peirce, Jeremy L.; Broman, Karl W.; Lu, Lu; Chesler, Elissa J.; Zhou, Guomin; Airey, David C.; Birmingham, Amanda E.; Williams, Robert W.

2008-01-01

175

Genome Reshuffling for Advanced Intercross Permutation (GRAIP): Simulation and permutation for advanced intercross population analysis  

SciTech Connect

Background: Advanced intercross lines (AIL) are segregating populations created using a multi-generation breeding protocol for fine mapping complex trait loci (QTL) in mice and other organisms. Applying QTL mapping methods for intercross and backcross populations, often followed by na ve permutation of individuals and phenotypes, does not account for the effect of AIL family structure in which final generations have been expanded and leads to inappropriately low significance thresholds. The critical problem with na ve mapping approaches in AIL populations is that the individual is not an exchangeable unit. Methodology/Principal Findings: The effect of family structure has immediate implications for the optimal AIL creation (many crosses, few animals per cross, and population expansion before the final generation) and we discuss these and the utility of AIL populations for QTL fine mapping. We also describe Genome Reshuffling for Advanced Intercross Permutation, (GRAIP) a method for analyzing AIL data that accounts for family structure. GRAIP permutes a more interchangeable unit in the final generation crosses - the parental genome - and simulating regeneration of a permuted AIL population based on exchanged parental identities. GRAIP determines appropriate genome-wide significance thresholds and locus-specific Pvalues for AILs and other populations with similar family structures. We contrast GRAIP with na ve permutation using a large densely genotyped mouse AIL population (1333 individuals from 32 crosses). A na ve permutation using coat color as a model phenotype demonstrates high false-positive locus identification and uncertain significance levels, which are corrected using GRAIP. GRAIP also detects an established hippocampus weight locus and a new locus, Hipp9a. Conclusions and Significance: GRAIP determines appropriate genome-wide significance thresholds and locus-specific Pvalues for AILs and other populations with similar family structures. The effect of family structure has immediate implications for the optimal AIL creation and we discuss these and the utility of AIL populations.

Pierce, Jeremy [University of Tennessee Health Science Center, Memphis; Broman, Karl [Johns Hopkins University; Lu, Lu [University of Tennessee Health Science Center, Memphis; Chesler, Elissa J [ORNL; Zhou, Guomin [University of Tennessee Health Science Center, Memphis; Airey, David [University of Tennessee Health Sciences Center, Memphis, TN; Birmingham, Amanda [Dharmacon, Inc.; Williams, Robert [University of Tennessee Health Science Center, Memphis

2008-04-01

176

Advanced Simulation and Computing: FY10-11 Implementation Plan, Volume 2, Rev. 0.  

National Technical Information Service (NTIS)

The Advanced Simulation and Computing Program (ASC) is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, to study advanced nuclear weapons design and manuf...

B. Carnes

2009-01-01

177

OPM model based simulation environment for systems engineering conceptualization phase  

Microsoft Academic Search

Conceptual design is a crucial system lifecycle stage, but systematic methods for conceptual design evaluation are not well-developed and existing approaches are not satisfactory. In this work we describe implementation and assessment of an advanced simulation environment that can serve conceptual design evaluation purposes using object-process methodology (OPM). The simulation exploits two major advantages of the OPM modeling language: its

Yevgeny Yaroker; Valeriya Perelman; Dov Dori

2009-01-01

178

Potential Modeling and Simulation Contributions to Specialized Undergraduate Pilot Training.  

ERIC Educational Resources Information Center

|Discussion of the use of advanced modeling and simulation technologies in training focuses on the Specialized Undergraduate Pilot Training program developed by the Air Force. Training challenges and needs are described and technology solutions are explained, including visual displays, computer-assisted instruction, instructional simulations, and…

Andrews, Dee H.; And Others

1996-01-01

179

ExtendSim advanced techology: Integrated simulation database  

Microsoft Academic Search

ExtendSim is used to model continuous, discrete event, discrete rate, and agent-based systems. This paper will focus on ExtendSim's tightly integrated simulation database which provides features that facilitate database-centric modeling and improve and streamline the modeling process.

Bob Diamond; David Krahl; Anthony Nastasi; Peter Tag

2010-01-01

180

Numerical Simulations and Optimisation in Forming of Advanced Materials  

SciTech Connect

With the introduction of new materials as high strength steels, metastable steels and fiber reinforce composites, the need for advanced physically valid constitutive models arises. A biaxial test equipment is developed and applied for the determination of material data as well as for validation of material models. An adaptive through- thickness integration scheme for plate elements is developed, which improves the accuracy of spring back prediction at minimal costs. An optimization strategy is proposed that assists an engineer to model an optimization problem.

Huetink, J. [University of Twente, Faculty of Engineering Technology, P.O.Box 217, 7500 AE Enschede (Netherlands)

2007-04-07

181

Numerical Simulations and Optimisation in Forming of Advanced Materials  

NASA Astrophysics Data System (ADS)

With the introduction of new materials as high strength steels, metastable steels and fiber reinforce composites, the need for advanced physically valid constitutive models arises. A biaxial test equipment is developed and applied for the determination of material data as well as for validation of material models. An adaptive through- thickness integration scheme for plate elements is developed, which improves the accuracy of spring back prediction at minimal costs. An optimization strategy is proposed that assists an engineer to model an optimization problem.

Huétink, J.

2007-04-01

182

Automatic modelling of reaction systems using genetic algorithms and its application to chemical vapour deposition processes: advanced utilizations of simulators for chemical systems  

NASA Astrophysics Data System (ADS)

The identification of appropriate reaction models is very helpful for developing chemical vapour deposition (CVD) processes. We introduced novel algorithms to analyse experimental data from CVD processes and identify reaction models automatically using genetic algorithms (GAs). The reaction models, which consist of various deposition species and gas-phase and surface reactions, were determined both quantitatively and qualitatively, based on chemical kinetics. The GA modelling algorithm consists of a process for calculating the predicted results from the reaction model candidates and a process for modifying the candidates by use of the difference between experimental and predicted results. We demonstrate the validity of this approach to successfully identify the appropriate reaction models from synthetic experimental data and real experimental data obtained during thermal CVD of tetraethylorthosilicate.

Takahashi, Takahiro; Funatsu, Kimito; Ema, Yoshinori

2005-01-01

183

Advanced optical fiber communication simulations in electrotechnical engineering education  

NASA Astrophysics Data System (ADS)

We present our efforts in education to apply advanced optical communication simulation software into our Electrical Engineering curriculum by implementing examples from theoretical courses with commercially available simulation software. Photonic design software is an interesting tool for the education of Engineers: these tools are able to simulate a huge variety of photonic components without major investments in student lab hardware. Moreover: some exotic phenomena ,which would usually involve specialty hardware, can be taught. We chose to implement VPItransmissionMaker from VPIsystems in the lab exercises for graduating Electrotechnical Engineers with majors in Photonics. The guideline we develop starts with basic examples provided by VPIsystems. The simplified simulation schemes serve as an introduction to the simulation techniques. Next, we highlight examples from the theoretical courses on Optical Telecommunications. A last part is an assignment where students have to design and simulate a system using real life component datasheets. The aim is to train them to interpret datasheets, to make design choices for their optical fiber system and to enhance their management skills. We detail our approach, highlight the educational aspects, the insight gained by the students, and illustrate our method with different examples.

Vervaeke, Michael; Nguyen Thi, Cac; Thienpont, Hugo

2004-10-01

184

Computer simulation models for sustainability  

Microsoft Academic Search

For the broad understanding of sustainable development, items such as seasonal change, timing of restrained harvesting and the rate of regeneration of natural resources, as well as the theories of population growth are crucial. Similarly, in the world of computing as a whole and computing simulation in particular, three important components of models are theory, data and program. A model

Hsin Chi

2000-01-01

185

Advanced Numerical Modeling of Turbulent Atmospheric Flows  

NASA Astrophysics Data System (ADS)

The present chapter introduces the method of computational simulation to predict and study turbulent atmospheric flows. This includes a description of the fundamental approach to computational simulation and the practical implementation using the technique of large-eddy simulation. In addition, selected contributions from IPA scientists to computational model development and various examples for applications are given. These examples include homogeneous turbulence, convective boundary layers, heated forest canopy, buoyant thermals, and large-scale flows with baroclinic wave instability.

Kühnlein, Christian; Dörnbrack, Andreas; Gerz, Thomas

186

MODELLING, SIMULATION AND SOFTWARE  

Microsoft Academic Search

The area of research is included in the European prioritary fundamental research in geometry, partial differential equations and mathematical modeling of engineering problems. The mathematical research, the solving, the optimization and the software methods will be integrated in the prioritary European themes, such as the use of the eolian and solar energy or fluid flows in the production of electric,

Emil STOICA

187

ADOME: An Advanced Object Modeling Environment  

Microsoft Academic Search

ADOME, which stands for ADvanced Object Modeling Environment, is an approach to integrating data and knowledge management based on object oriented technology. Next generation information systems will require more flexible data modeling capabilities than those provided by current object oriented DBMSs. In particular, integration of data and knowledge management capabilities will become increasingly important. In this context, ADOME provides versatile

Qing Li; Frederick H. Lochovsky

1998-01-01

188

Modeling of Spacecraft Advanced Chemical Propulsion Systems.  

National Technical Information Service (NTIS)

This paper outlines the development of the Advanced Chemical Propulsion System (ACPS) model for Earth and Space Storable propellants. This model was developed by the System Technology Operation of SAIC-Huntsville for the NASA MSFC In-Space Propulsion Proj...

M. P. J. Benfield J. A. Belcher

2004-01-01

189

Benchmark Dose Modeling - Advanced Topics Course  

EPA Science Inventory

Benchmark Dose ModelingAdvanced Topics Course The objectives of this full-day course are to provide participants with training on how to use the U.S. Environmental Protection Agency’s (EPA) Benchmark Dose Modeling Software (BMDS) and related software programs to fa...

190

Advanced Life Cycle Cost Modeling  

Microsoft Academic Search

Systems for future civilian and military space missions on a national or international basis will be selected with life cycle cost (LCC) as a primary evaluation criterion. It reflects the current realization that only systems which are considered affordable will be built in the future due to the constraints in national budgets. This environment calls for innovative cost modeling techniques

Claus J. Meisl

1989-01-01

191

Inferno: a functional simulation infrastructure for modeling microarchitectural data speculations  

Microsoft Academic Search

This paper presents key insights and design rationales behind Inferno, a functional simulation construction framework developed at Intel to support execution-driven cycle-accurate performance modeling and simulation of advanced microarchitectural data speculation techniques for future processor designs and explorations. Inferno divides the task of functional simulation into three essential components, namely: (1) context manager of in-flight speculatively executed instructions, (2) stateless

Hong Wang; Shiri Manor; Dave Lafollette; Nadav Nesher; Ku-jei King; Perry H. Wang; Shay Levy; Shai Satt; Gal Carmeli; Arjun Kapur; Ioannis Schoinas; Ed Rubinstein; Rahul Bhatt

2003-01-01

192

Stochastic models: theory and simulation.  

SciTech Connect

Many problems in applied science and engineering involve physical phenomena that behave randomly in time and/or space. Examples are diverse and include turbulent flow over an aircraft wing, Earth climatology, material microstructure, and the financial markets. Mathematical models for these random phenomena are referred to as stochastic processes and/or random fields, and Monte Carlo simulation is the only general-purpose tool for solving problems of this type. The use of Monte Carlo simulation requires methods and algorithms to generate samples of the appropriate stochastic model; these samples then become inputs and/or boundary conditions to established deterministic simulation codes. While numerous algorithms and tools currently exist to generate samples of simple random variables and vectors, no cohesive simulation tool yet exists for generating samples of stochastic processes and/or random fields. There are two objectives of this report. First, we provide some theoretical background on stochastic processes and random fields that can be used to model phenomena that are random in space and/or time. Second, we provide simple algorithms that can be used to generate independent samples of general stochastic models. The theory and simulation of random variables and vectors is also reviewed for completeness.

Field, Richard V., Jr.

2008-03-01

193

Phase advance after one or three simulated dawns in humans.  

PubMed

A specially designed apparatus that can simulate the waveform of the dawn or dusk signal at any latitude and any day of the year has been shown to phase shift the circadian pacemaker in rodents and primates at a fraction of the illuminance previously used. Until recently, it was considered that rather high illuminances or rather long exposure episodes to room light were necessary to phase shift human circadian rhythms. This experiment shows that, under controlled conditions of a modified constant routine protocol, a single dawn signal is sufficient to phase advance the timing of the onset of secretion of the pineal hormone melatonin. The significant phase advance of salivary melatonin of 20 minutes, which is enhanced to 34 minutes after three consecutive dawn signals, is small, but appears to be of sufficient magnitude to entrain the human circadian pacemaker, which has an endogenous period of about 24.2h. PMID:11023213

Danilenko, K V; Wirz-Justice, A; Kräuchi, K; Cajochen, C; Weber, J M; Fairhurst, S; Terman, M

2000-09-01

194

AFDM: An Advanced Fluid-Dynamics Model  

Microsoft Academic Search

This report consists of three parts. First, for the standard Advanced Fluid-Dynamics Model (AFDM), heat-transfer coefficients between components are worked out, depending on the different possible topologies. Conduction, convection, and radiative heat-transfer mechanisms are modeled. For solid particles, discontinuous phases that obey a rigid'' model, and components lacking relative motion, heat transfer is by conduction. Convection is represented for fluids

J. Berthier; D. Wilhelm; W. R. Bohl

1990-01-01

195

Nanowire array for wireless neural Probe: modeling and simulation  

NASA Astrophysics Data System (ADS)

Recent advances in nanotechnology have stimulated a renewed interest in multisite recording of electrical activity of network of neurons, particularly using nanobiomaterials. This paper presents the simulation of electrical response of neurons cultured on microelectrode arrays based on the electronic equivalent model using Cadence PSD 15.0. The results were compared with those previously published models such as Kupfmuller and Jenik's model, McGrogan's Neuron Model which are based on the Hodgkin and Huxley model. We have developed and equivalent circuit model using discrete passive components to simulate the electrical activity of the neurons. It is observed that present equivalent model gives more accurate results with short computation time.

Chintakuntla, Ritesh R.; Abraham, Jose K.; Varadan, Vijay K.

2006-04-01

196

EGR Distribution in Engine Cylinders Using Advanced Virtual Simulation  

SciTech Connect

Exhaust Gas Recirculation (EGR) is a well-known technology for reduction of NOx in diesel engines. With the demand for extremely low engine out NOx emissions, it is important to have a consistently balanced EGR flow to individual engine cylinders. Otherwise, the variation in the cylinders' NOx contribution to the overall engine emissions will produce unacceptable variability. This presentation will demonstrate the effective use of advanced virtual simulation in the development of a balanced EGR distribution in engine cylinders. An initial design is analyzed reflecting the variance in the EGR distribution, quantitatively and visually. Iterative virtual lab tests result in an optimized system.

Fan, Xuetong

2000-08-20

197

The Advanced Gamma-ray Imaging System (AGIS): Simulation studies  

SciTech Connect

The Advanced Gamma-ray Imaging System (AGIS) is a next-generation ground-based gamma-ray observatory being planned in the U.S. The anticipated sensitivity of AGIS is about one order of magnitude better than the sensitivity of current observatories, allowing it to measure gamma-ray emission from a large number of Galactic and extra-galactic sources. We present here results of simulation studies of various possible designs for AGIS. The primary characteristics of the array performance - collecting area, angular resolution, background rejection, and sensitivity - are discussed.

Maier, G.; /McGill U.; Buckley, J.; /Washington U., St. Louis; Bugaev, V.; /Washington U., St. Louis; Fegan, S.; /UCLA; Funk, S.; /SLAC; Konopelko, A.; /Pittsburgh U.; Vassiliev, V.V.; /UCLA

2011-06-14

198

Stochastic modeling in reservoir simulation  

SciTech Connect

This paper outlines details of a method that includes uncertainty in deterministic simulations of oil and gas reservoirs. The method uses the probability distributions of reservoir and geological properties to obtain a likelihood distribution of the output variables. The Monte Carlo sampling (MCS) method is often-applied, but it is impractical for simulation studies because the number of computations becomes excessive. This paper uses an analytical thermal screening model to compare various variance-reduction methods with MCS simulations. The Latin hypercube sampling (LHS) method is then selected to conduct numerical simulations. The method allows computation of the partial correlation coefficients, which, as demonstrated, can be used to determine the sensitivity of process variables.

Ding, L.Y.; Mehra, R.K.; Donnelly, J.K. (BP Resources Canada Ltd. (CA))

1992-02-01

199

Recent advances of strong-strong beam-beam simulation  

SciTech Connect

In this paper, we report on recent advances in strong-strong beam-beam simulation. Numerical methods used in the calculation of the beam-beam forces are reviewed. A new computational method to solve the Poisson equation on nonuniform grid is presented. This method reduces the computational cost by a half compared with the standard FFT based method on uniform grid. It is also more accurate than the standard method for a colliding beam with low transverse aspect ratio. In applications, we present the study of coherent modes with multi-bunch, multi-collision beam-beam interactions at RHIC. We also present the strong-strong simulation of the luminosity evolution at KEKB with and without finite crossing angle.

Qiang, Ji; Furman, Miguel A.; Ryne, Robert D.; Fischer, Wolfram; Ohmi,Kazuhito

2004-09-15

200

Recent advances in modeling stellar interiors (u)  

SciTech Connect

Advances in stellar interior modeling are being driven by new data from large-scale surveys and high-precision photometric and spectroscopic observations. Here we focus on single stars in normal evolutionary phases; we will not discuss the many advances in modeling star formation, interacting binaries, supernovae, or neutron stars. We review briefly: (1) updates to input physics of stellar models; (2) progress in two and three-dimensional evolution and hydrodynamic models; (3) insights from oscillation data used to infer stellar interior structure and validate model predictions (asteroseismology). We close by highlighting a few outstanding problems, e.g., the driving mechanisms for hybrid {gamma} Dor/{delta} Sct star pulsations, the cause of giant eruptions seen in luminous blue variables such as {eta} Car and P Cyg, and the solar abundance problem.

Guzik, Joyce Ann [Los Alamos National Laboratory

2010-01-01

201

VTI Driving Simulator: Mathematical Model of a Four-wheeled Vehicle for Simulation in Real Time. VTI Rapport 267A.  

ERIC Educational Resources Information Center

|This report contains a theoretical model for describing the motion of a passenger car. The simulation program based on this model is used in conjunction with an advanced driving simulator and run in real time. The mathematical model is complete in the sense that the dynamics of the engine, transmission and steering system is described in some…

Nordmark, Staffan

1984-01-01

202

Economic Analysis. Computer Simulation Models.  

ERIC Educational Resources Information Center

A multimedia course in economic analysis was developed and used in conjunction with the United States Naval Academy. (See ED 043 790 and ED 043 791 for final reports of the project evaluation and development model.) This volume of the text discusses the simulation of behavioral relationships among variable elements in an economy and presents…

Sterling Inst., Washington, DC. Educational Technology Center.

203

Modeling and simulation of microturbine  

Microsoft Academic Search

In this work, modeling, simulation and analysis of load following behaviour of microturbine (MT) as a Distributed Energy Resource (DER) have been performed. The system comprises a MT interconnected to the utility grid. The MT is capable of operating in both islanded and grid-connected modes. This work considers that the MT supplies power to variable general and critical loads. The

A. K. Saha; S. Chowdhury

2010-01-01

204

Conversion modelling: simulating tree stems  

Microsoft Academic Search

Profit in a competitive environment requires information to support efficient resource use in all endeavours including the forest and wood industry. The capacity to estimate value of a stand by modelling trees and simulating conversion along the whole value chain offers the potential to maximise efficiency, by enabling virtual trials of different production, processing and utilisation scenarios. Such a system

Graeme Palmer

2010-01-01

205

Modelling and simulation of gyrotrons  

Microsoft Academic Search

Modelling and simulation of gyrotrons have two interconnected aspects, namely beam formation in the electron-optical system (EOS) and beam-field interaction in the resonant cavity. In this paper we address both problems and outline the physical models and numerical techniques implemented in our problem-oriented package of computer codes. In order to illustrate our approach we present some results of numerical experiments

S. Sabchevski; T. Idehara; M. Glyavin; I. Ogawa; S. Mitsudo

2005-01-01

206

Simulation, Modelling and Visualisation: Toolkits for Building Simulated Worlds  

Microsoft Academic Search

Simulation and Modelling continue to play important roles underpining the computational sciences (1). In Computer Science we have a number of on-going simulation projects making use of field equation models, micro- scopic entity models and particle models to support research with Cahn- Hillard Cook (2) and Ginzburg-Landau equations, artificial agent models (predator-prey systems, battlefield simulations, robot tanks, robot soccer), planetary

D. P. Playne; A. P. Gerdelan; K. A. Hawick

207

Family of systems simulation (FOSSIM): a collaborative approach to FoS modeling and simulation  

NASA Astrophysics Data System (ADS)

Significant advances are being made in the application of Modeling and Simulation (M&S) technologies to support Government initiatives for Simulation Based Acquisition (SBA) and Simulation, Test and Evaluation Process (STEP) in the Army transformation. This paper describes a collaborative approach to Family of Systems (FoS) M&S in use on the FOSSIM program to evaluate critical Theater Air and Missile Defense (TAMD) integration and interoperability issues and to explore opportunities for advanced technology exploitation. This paper provides an overview of the FOSSIM concept and describes the collaborative development and utilization methodology. Key topics discussed include Systems Engineering and Design, Model Engineering and Development, Systems Analysis, and Configuration Management (CM). The paper concludes by summarizing the FOSSIM simulation environment and modeling capabilities.

Wymer, Debra; Washburn, Ray; Colvert, Phil; Cunefare, Dave

2001-09-01

208

Surrogate Model Development for Fuels for Advanced Combustion Engines  

SciTech Connect

The fuels used in internal-combustion engines are complex mixtures of a multitude of different types of hydrocarbon species. Attempting numerical simulations of combustion of real fuels with all of the hydrocarbon species included is highly unrealistic. Thus, a surrogate model approach is generally adopted, which involves choosing a few representative hydrocarbon species whose overall behavior mimics the characteristics of the target fuel. The present study proposes surrogate models for the nine fuels for advanced combustion engines (FACE) that have been developed for studying low-emission, high-efficiency advanced diesel engine concepts. The surrogate compositions for the fuels are arrived at by simulating their distillation profiles to within a maximum absolute error of 4% using a discrete multi-component (DMC) fuel model that has been incorporated in the multi-dimensional computational fluid dynamics (CFD) code, KIVA-ERC-CHEMKIN. The simulated surrogate compositions cover the range and measured concentrations of the various hydrocarbon classes present in the fuels. The fidelity of the surrogate fuel models is judged on the basis of matching their specific gravity, lower heating value, hydrogen/carbon (H/C) ratio, cetane number, and cetane index with the measured data for all nine FACE fuels.

Anand, Krishnasamy [University of Wisconsin, Madison; Ra, youngchul [University of Wisconsin, Madison; Reitz, Rolf [University of Wisconsin; Bunting, Bruce G [ORNL

2011-01-01

209

Recent Advances in molecular simulations of ion solvation at liquid interfaces  

SciTech Connect

In this paper, I present a review of the application of molecular dynamics simulation methods, including which polarizable potential models were used to describe interactions among species, to a variety of chemical and physical processes in solutions and at interfaces. The main emphasis of the review is on recent advances in the understanding of ion solvation, molecular association, and molecular solvation at liquid interfaces. The molecules discussed range from monovalent ions to molecular ions such as hydronium and nitrate ions. The computed properties include potentials of mean force, surface potentials, surface tensions, and density profiles. Comparisons with other simulation studies and experimental results were made and discussed in the review.

Chang, Tsun-Mei; Dang, Liem X.

2006-01-01

210

Modeling and Simulation for Safeguards  

SciTech Connect

The purpose of this talk is to give an overview of the role of modeling and simulation in Safeguards R&D and introduce you to (some of) the tools used. Some definitions are: (1) Modeling - the representation, often mathematical, of a process, concept, or operation of a system, often implemented by a computer program; (2) Simulation - the representation of the behavior or characteristics of one system through the use of another system, especially a computer program designed for the purpose; and (3) Safeguards - the timely detection of diversion of significant quantities of nuclear material. The role of modeling and simulation are: (1) Calculate amounts of material (plant modeling); (2) Calculate signatures of nuclear material etc. (source terms); and (3) Detector performance (radiation transport and detection). Plant modeling software (e.g. FACSIM) gives the flows and amount of material stored at all parts of the process. In safeguards this allow us to calculate the expected uncertainty of the mass and evaluate the expected MUF. We can determine the measurement accuracy required to achieve a certain performance.

Swinhoe, Martyn T. [Los Alamos National Laboratory

2012-07-26

211

Multiscale Stochastic Simulation and Modeling  

SciTech Connect

Acceleration driven instabilities of fluid mixing layers include the classical cases of Rayleigh-Taylor instability, driven by a steady acceleration and Richtmyer-Meshkov instability, driven by an impulsive acceleration. Our program starts with high resolution methods of numerical simulation of two (or more) distinct fluids, continues with analytic analysis of these solutions, and the derivation of averaged equations. A striking achievement has been the systematic agreement we obtained between simulation and experiment by using a high resolution numerical method and improved physical modeling, with surface tension. Our study is accompanies by analysis using stochastic modeling and averaged equations for the multiphase problem. We have quantified the error and uncertainty using statistical modeling methods.

James Glimm; Xiaolin Li

2006-01-10

212

Combustion modeling in advanced gas turbine systems  

SciTech Connect

Goal of DOE`s Advanced Turbine Systems program is to develop and commercialize ultra-high efficiency, environmentally superior, cost competitive gas turbine systems for base-load applications in utility, independent power producer, and industrial markets. Primary objective of the program here is to develop a comprehensive combustion model for advanced gas turbine combustion systems using natural gas (coal gasification or biomass fuels). The efforts included code evaluation (PCGC-3), coherent anti-Stokes Raman spectroscopy, laser Doppler anemometry, and laser-induced fluorescence.

Smoot, L.D.; Hedman, P.O.; Fletcher, T.H.; Brewster, B.S.; Kramer, S.K. [Brigham Young Univ., Provo, UT (United States). Advanced Combustion Engineering Research Center

1995-12-31

213

Simulation and modeling of homogeneous, compressed turbulence  

NASA Astrophysics Data System (ADS)

Low Reynolds number homogeneous turbulence undergoing low Mach number isotropic and one-dimensional compression was simulated by numerically solving the Navier-Stokes equations. The numerical simulations were performed on a CYBER 205 computer using a 64 x 64 x 64 mesh. A spectral method was used for spatial differencing and the second-order Runge-Kutta method for time advancement. A variety of statistical information was extracted from the computed flow fields. These include three-dimensional energy and dissipation spectra, two-point velocity correlations, one-dimensional energy spectra, turbulent kinetic energy and its dissipation rate, integral length scales, Taylor microscales, and Kolmogorov length scale. Results from the simulated flow fields were used to test one-point closure, two-equation models. A new one-point-closure, three-equation turbulence model which accounts for the effect of compression is proposed. The new model accurately calculates four types of flows (isotropic decay, isotropic compression, one-dimensional compression, and axisymmetric expansion flows) for a wide range of strain rates.

Wu, C. T.; Ferziger, J. H.; Chapman, D. R.

1985-05-01

214

A Simulation and Modeling Framework for Space Situational Awareness  

SciTech Connect

This paper describes the development and initial demonstration of a new, integrated modeling and simulation framework, encompassing the space situational awareness enterprise, for quantitatively assessing the benefit of specific sensor systems, technologies and data analysis techniques. The framework is based on a flexible, scalable architecture to enable efficient, physics-based simulation of the current SSA enterprise, and to accommodate future advancements in SSA systems. In particular, the code is designed to take advantage of massively parallel computer systems available, for example, at Lawrence Livermore National Laboratory. The details of the modeling and simulation framework are described, including hydrodynamic models of satellite intercept and debris generation, orbital propagation algorithms, radar cross section calculations, optical brightness calculations, generic radar system models, generic optical system models, specific Space Surveillance Network models, object detection algorithms, orbit determination algorithms, and visualization tools. The use of this integrated simulation and modeling framework on a specific scenario involving space debris is demonstrated.

Olivier, S S

2008-09-15

215

Advanced coal gasifier designs using large-scale simulations  

SciTech Connect

Porting of the legacy code MFIX to a high performance computer (HPC) and the use of high resolution simulations for the design of a coal gasifier are described here. MFIX is based on a continuum multiphase flow model that considers gas and solids to form interpenetrating continua. Low resolution simulations of a commercial scale gasifier with a validated MFIX model revealed interesting physical phenomena with implications on the gasifier design, which prompted the study reported here. To be predictive, the simulations need to model the spatiotemporal variations in gas and solids volume fractions, velocities, temperatures with any associated phase change and chemical reactions. These processes occur at various time- and length-scales requiring very high spatial resolution and large number of iterations with small time-steps. We were able to perform perhaps the largest known simulations of gas-solids reacting flows, providing detailed information about the gas-solids flow structure and the pressure, temperature and species distribution in the gasifier. One key finding is the new features of the coal jet trajectory revealed with the high spatial resolution, which provides information on the accuracy of the lower resolution simulations. Methodologies for effectively combining high and low resolution simulations for design studies must be developed. From a computational science perspective, we found that global communication has to be reduced to achieve scalability to 1000s of cores, hybrid parallelization is required to effectively utilize the multicore chips, and the wait time in the batch queue significantly increases the actual time-to-solution. From our experience, development is required in the following areas: efficient solvers for heterogeneous, massively parallel systems; data analysis tools to extract information from large data sets; and programming environments for easily porting legacy codes to HPC.

Syamlal, M [National Energy Technology Laboratory (NETL); Guenther, Chris [National Energy Technology Laboratory (NETL); Gel, Aytekin [Aeolus Research Inc.; Pannala, Sreekanth [ORNL

2009-01-01

216

Advanced modelling of optical coherence tomography systems.  

PubMed

Analytical and numerical models for describing and understanding the light propagation in samples imaged by optical coherence tomography (OCT) systems are presented. An analytical model for calculating the OCT signal based on the extended Huygens-Fresnel principle valid both for the single and multiple scattering regimes is reviewed. An advanced Monte Carlo model for calculating the OCT signal is also reviewed, and the validity of this model is shown through a mathematical proof based on the extended Huygens-Fresnel principle. Moreover, for the first time the model is verified experimentally. From the analytical model, an algorithm for enhancing OCT images is developed: the so-called true-reflection algorithm in which the OCT signal may be corrected for the attenuation caused by scattering. For the first time, the algorithm is demonstrated by using the Monte Carlo model as a numerical tissue phantom. Such algorithm holds promise for improving OCT imagery and to extend the possibility for functional imaging. PMID:15128207

Andersen, Peter E; Thrane, Lars; Yura, Harold T; Tycho, Andreas; Jørgensen, Thomas M; Frosz, Michael H

2004-04-01

217

Advanced Simulation and Computing Fiscal Year 2011-2012 Implementation Plan, Revision 0  

SciTech Connect

The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the surety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with current and future non-nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering (D&E) programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of current facilities and programs along with new experimental facilities and computational enhancements to support these programs. The Advanced Simulation and Computing Program (ASC) is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, to study advanced nuclear weapons design and manufacturing processes, to analyze accident scenarios and weapons aging, and to provide the tools to enable stockpile Life Extension Programs (LEPs) and the resolution of Significant Finding Investigations (SFIs). This requires a balanced resource, including technical staff, hardware, simulation software, and computer science solutions. In its first decade, the ASC strategy focused on demonstrating simulation capabilities of unprecedented scale in three spatial dimensions. In its second decade, ASC is focused on increasing its predictive capabilities in a three-dimensional (3D) simulation environment while maintaining support to the SSP. The program continues to improve its unique tools for solving progressively more difficult stockpile problems (focused on sufficient resolution, dimensionality and scientific details); to quantify critical margins and uncertainties (QMU); and to resolve increasingly difficult analyses needed for the SSP. Moreover, ASC has restructured its business model from one that was very successful in delivering an initial capability to one that is integrated and focused on requirements-driven products that address long-standing technical questions related to enhanced predictive capability in the simulation tools. ASC must continue to meet three objectives: Objective 1 - Robust Tools. Develop robust models, codes, and computational techniques to support stockpile needs such as refurbishments, SFIs, LEPs, annual assessments, and evolving future requirements. Objective 2 - Prediction through Simulation. Deliver validated physics and engineering tools to enable simulations of nuclear weapons performance in a variety of operational environments and physical regimes and to enable risk-informed decisions about the performance, safety, and reliability of the stockpile. Objective 3 - Balanced Operational Infrastructure. Implement a balanced computing platform acquisition strategy and operational infrastructure to meet Directed Stockpile Work (DSW) and SSP needs for capacity and high-end simulation capabilities.

McCoy, M; Phillips, J; Hpson, J; Meisner, R

2010-04-22

218

Advanced Simulation and Computing FY10-11 Implementation Plan Volume 2, Rev. 0  

SciTech Connect

The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the surety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with current and future non-nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of current facilities and programs along with new experimental facilities and computational enhancements to support these programs. The Advanced Simulation and Computing Program (ASC) is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, to study advanced nuclear weapons design and manufacturing processes, to analyze accident scenarios and weapons aging, and to provide the tools to enable stockpile Life Extension Programs (LEPs) and the resolution of Significant Finding Investigations (SFIs). This requires a balanced resource, including technical staff, hardware, simulation software, and computer science solutions. In its first decade, the ASC strategy focused on demonstrating simulation capabilities of unprecedented scale in three spatial dimensions. In its second decade, ASC is focused on increasing its predictive capabilities in a three-dimensional simulation environment while maintaining support to the SSP. The program continues to improve its unique tools for solving progressively more difficult stockpile problems (focused on sufficient resolution, dimensionality and scientific details); to quantify critical margins and uncertainties (QMU); and to resolve increasingly difficult analyses needed for the SSP. Moreover, ASC has restructured its business model from one that was very successful in delivering an initial capability to one that is integrated and focused on requirements-driven products that address long-standing technical questions related to enhanced predictive capability in the simulation tools. ASC must continue to meet three objectives: Objective 1 Robust Tools--Develop robust models, codes, and computational techniques to support stockpile needs such as refurbishments, SFIs, LEPs, annual assessments, and evolving future requirements. Objective 2 Prediction through Simulation--Deliver validated physics and engineering tools to enable simulations of nuclear weapons performance in a variety of operational environments and physical regimes and to enable risk-informed decisions about the performance, safety, and reliability of the stockpile. Objective 3 Balanced Operational Infrastructure--Implement a balanced computing platform acquisition strategy and operational infrastructure to meet Directed Stockpile Work (DSW) and SSP needs for capacity and high-end simulation capabilities.

Carnes, B

2009-06-08

219

First Transport Code Simulations using the TGLF Model  

Microsoft Academic Search

The first transport code simulations using the newly developed TGLF theory-based transport model [1,2] are presented. TGLF has comprehensive physics to approximate the turbulent transport due to drift-ballooning modes in tokamaks. The TGLF model is a next generation gyro-Landau-fluid model that includes several recent advances that remove the limitations of its predecessor, GLF23. The model solves for the linear eigenmodes

J. E. Kinsey

2007-01-01

220

New routes to advanced simulation of material forming  

NASA Astrophysics Data System (ADS)

We developed in recent years a novel technique, called Proper Generalized Decomposition (PGD), based on the assumption of a separated form of the unknown field. It has demonstrated its capabilities in dealing with highdimensional problems overcoming the strong limitations of classical approaches. Many challenging problems can be efficiently cast into a multidimensional framework. For instance, parameters in a model (loads, initial conditions, boundary conditions, material parameters, geometrical parameters,...) can be set as additional extra-coordinates of the model. In a PGD framework, the resulting model is solved once for life, in order to obtain a general solution that includes all the solutions for every possible value of the parameters, that is, a sort virtual chart. Under this rationale, optimization of complex problems, uncertainty quantification, simulation-based control and real-time simulation are now at hand, in highly complex scenarios and on deployed platforms.

Chinesta, Francisco; Leygue, Adrien; Bordeu, Felipe

2013-05-01

221

Specification of advanced safety modeling requirements (Rev. 0).  

SciTech Connect

The U.S. Department of Energy's Global Nuclear Energy Partnership has lead to renewed interest in liquid-metal-cooled fast reactors for the purpose of closing the nuclear fuel cycle and making more efficient use of future repository capacity. However, the U.S. has not designed or constructed a fast reactor in nearly 30 years. Accurate, high-fidelity, whole-plant dynamics safety simulations will play a crucial role by providing confidence that component and system designs will satisfy established design limits and safety margins under a wide variety of operational, design basis, and beyond design basis transient conditions. Current modeling capabilities for fast reactor safety analyses have resulted from several hundred person-years of code development effort supported by experimental validation. The broad spectrum of mechanistic and phenomenological models that have been developed represent an enormous amount of institutional knowledge that needs to be maintained. Complicating this, the existing code architectures for safety modeling evolved from programming practices of the 1970s. This has lead to monolithic applications with interdependent data models which require significant knowledge of the complexities of the entire code in order for each component to be maintained. In order to develop an advanced fast reactor safety modeling capability, the limitations of the existing code architecture must be overcome while preserving the capabilities that already exist. To accomplish this, a set of advanced safety modeling requirements is defined, based on modern programming practices, that focuses on modular development within a flexible coupling framework. An approach for integrating the existing capabilities of the SAS4A/SASSYS-1 fast reactor safety analysis code into the SHARP framework is provided in order to preserve existing capabilities while providing a smooth transition to advanced modeling capabilities. In doing this, the advanced fast reactor safety models will target leadership-class computing architectures for massively-parallel high-fidelity computations while providing continued support for rapid prototyping using modest fidelity computations on multiple-core desktop platforms.

Fanning, T. H.; Tautges, T. J.

2008-06-30

222

The ModelAssembler Community Modeling Environment (MA-CME): Expanded Access to Advanced Seismic Computation  

NASA Astrophysics Data System (ADS)

We introduce MA-CME, an open-source environment for all PCs, Macs, and workstations that configures advanced seismic modeling runs. It is intended for use by seismologists, engineers, and students. The environment combines geologic and geotechnical data sets with gridding, modeling, and output specifications into portal packs for execution on standalone workstations, clusters, and mega-facilities such as Sun Grid. A tutorial interface helps the user scale the grid to the facilities available, from small test runs to efforts requiring major resources. The input geologic data are kept in open, editable forms to promote the creation of models for new areas, the regional extension of existing grids, and the detailing of critical features within current models. MA-CME currently drives computations with the E3D and the open-source E3D/CODE3 advanced simulation platforms; additional platforms will be added. The ability of MA-CME to configure computations at a range of scales and model complexity is intended to promote wide use of advanced seismic modeling. Wide community use may lead to breakthrough insights into how geology controls earthquake ground motion. Advanced seismic modeling platforms, coupled with increasing availability of faster clusters, have rapidly improved the realism of such deterministic simulations. Yet the number of people able to configure and successfully run simulations through complex geology has not grown. Ground-motion simulations have been published only for a few scenarios in a limited number of urban areas. MA-CME has been used to configure simulations to 2-Hz frequency for the Reno and Las Vegas, Nevada; Grenoble, France; and Wellington, New Zealand regions including multiple basins, detailed geotechnical maps, and attenuation. The package is freely available on the web. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Louie, J. N.; Larsen, S.

2006-12-01

223

VISION: Verifiable Fuel Cycle Simulation Model  

SciTech Connect

The nuclear fuel cycle is a very complex system that includes considerable dynamic complexity as well as detail complexity. In the nuclear power realm, there are experts and considerable research and development in nuclear fuel development, separations technology, reactor physics and waste management. What is lacking is an overall understanding of the entire nuclear fuel cycle and how the deployment of new fuel cycle technologies affects the overall performance of the fuel cycle. The Advanced Fuel Cycle Initiative’s systems analysis group is developing a dynamic simulation model, VISION, to capture the relationships, timing and delays in and among the fuel cycle components to help develop an understanding of how the overall fuel cycle works and can transition as technologies are changed. This paper is an overview of the philosophy and development strategy behind VISION. The paper includes some descriptions of the model and some examples of how to use VISION.

Jacob J. Jacobson; Abdellatif M. Yacout; Gretchen E. Matthern; Steven J. Piet; David E. Shropshire

2009-04-01

224

Validation of GATE Monte Carlo simulations of the GE Advance/Discovery LS PET scanners  

SciTech Connect

The recently developed GATE (GEANT4 application for tomographic emission) Monte Carlo package, designed to simulate positron emission tomography (PET) and single photon emission computed tomography (SPECT) scanners, provides the ability to model and account for the effects of photon noncollinearity, off-axis detector penetration, detector size and response, positron range, photon scatter, and patient motion on the resolution and quality of PET images. The objective of this study is to validate a model within GATE of the General Electric (GE) Advance/Discovery Light Speed (LS) PET scanner. Our three-dimensional PET simulation model of the scanner consists of 12 096 detectors grouped into blocks, which are grouped into modules as per the vendor's specifications. The GATE results are compared to experimental data obtained in accordance with the National Electrical Manufactures Association/Society of Nuclear Medicine (NEMA/SNM), NEMA NU 2-1994, and NEMA NU 2-2001 protocols. The respective phantoms are also accurately modeled thus allowing us to simulate the sensitivity, scatter fraction, count rate performance, and spatial resolution. In-house software was developed to produce and analyze sinograms from the simulated data. With our model of the GE Advance/Discovery LS PET scanner, the ratio of the sensitivities with sources radially offset 0 and 10 cm from the scanner's main axis are reproduced to within 1% of measurements. Similarly, the simulated scatter fraction for the NEMA NU 2-2001 phantom agrees to within less than 3% of measured values (the measured scatter fractions are 44.8% and 40.9{+-}1.4% and the simulated scatter fraction is 43.5{+-}0.3%). The simulated count rate curves were made to match the experimental curves by using deadtimes as fit parameters. This resulted in deadtime values of 625 and 332 ns at the Block and Coincidence levels, respectively. The experimental peak true count rate of 139.0 kcps and the peak activity concentration of 21.5 kBq/cc were matched by the simulated results to within 0.5% and 0.1% respectively. The simulated count rate curves also resulted in a peak NECR of 35.2 kcps at 10.8 kBq/cc compared to 37.6 kcps at 10.0 kBq/cc from averaged experimental values. The spatial resolution of the simulated scanner matched the experimental results to within 0.2 mm.

Schmidtlein, C. Ross; Kirov, Assen S.; Nehmeh, Sadek A.; Erdi, Yusuf E.; Humm, John L.; Amols, Howard I.; Bidaut, Luc M.; Ganin, Alex; Stearns, Charles W.; McDaniel, David L.; Hamacher, Klaus A. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York 10021 (United States); Department of Imaging Physics, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, Texas 77230-1439 (United States); GE Healthcare Technologies, 3000 N. Grandview Blvd., Waukesha, Wisconsin 53188 (United States); Weill Medical College of Cornell University, 525 East 68th Street, New York, New York 10021 (United States)

2006-01-15

225

Conceptual interoperability model of NCW simulation  

Microsoft Academic Search

Network centric warfare (NCW) need to be supported by modeling and simulation systems, and the interoperability between different simulation systems is an important aspect to realize cooperation of varied military simulation systems and establish common simulation environment. However, complexities of the NCW and individual military simulation systems make the interoperability difficult to achieve. A large body of work shows that

Yuanzheng Ge; Xiaogang Qiu; Kedi Huang

2010-01-01

226

Advanced Distributed Simulation Technology Advanced Rotary Wing Aircraft. System/Segment Specification. Volume 3. Visual System Module.  

National Technical Information Service (NTIS)

The ADST ARWA System/Segment Specification establishes the functional requirements for the Advanced Rotary Wing Aircraft (ARWA) Simulator System (SS). Volume III describes the requirements for the Visual System Module (VSM). The VSM component provides fun...

R. Branson R. Anschuetz

1994-01-01

227

Advances in modeling of biomolecular interactions1  

Microsoft Academic Search

Modeling of molecular interactions is increasingly used in life science research and biotechnology development. Examples are computer aided drug design, prediction of protein interactions with other molecules, and simulation of networks of biomolecules in a particular process in human body. This article reviews recent progress in the related fields and provides a brief overview on the methods used in molecular

Cong-zhong CAI; Ze-rong LI; Wan-lu WANG; Yu-zong CHEN

228

Advances in Sun-Earth Connection Modeling  

Microsoft Academic Search

Space weather forecasting is a focus of a multidisciplinary research effort motivated by a sensitive dependence of many modern technologies on geospace conditions. Adequate understanding of the physics of the Sun-Earth connection and associated multi-scale magnetospheric and ionospheric processes is an essential part of this effort. Modern physical simulation models such as multimoment multifluid models with effective coupling from small-scale

S. B. Ganguli; V. V. Gavrishchaka

2003-01-01

229

Promodel: simulation modeling using promodel technology  

Microsoft Academic Search

PROMODEL's simulation modeling products are powerful yet easy-to-use simulation tools for modeling all types of systems and processes. ProModel® is designed to model manufacturing systems ranging from small job shops and machining cells to large mass production, flexible manufacturing systems, and supply chain systems. Other simulation products available from PROMODEL Corporation include MedModel®, ServiceModel®, InnovateTM, and ProModel PITM (for process

Charles R. Harrell; Rochelle N. Price

2002-01-01

230

CAPE-OPEN Integration for Advanced Process Engineering Co-Simulation  

SciTech Connect

This paper highlights the use of the CAPE-OPEN (CO) standard interfaces in the Advanced Process Engineering Co-Simulator (APECS) developed at the National Energy Technology Laboratory (NETL). The APECS system uses the CO unit operation, thermodynamic, and reaction interfaces to provide its plug-and-play co-simulation capabilities, including the integration of process simulation with computational fluid dynamics (CFD) simulation. APECS also relies heavily on the use of a CO COM/CORBA bridge for running process/CFD co-simulations on multiple operating systems. For process optimization in the face of multiple and some time conflicting objectives, APECS offers stochastic modeling and multi-objective optimization capabilities developed to comply with the CO software standard. At NETL, system analysts are applying APECS to a wide variety of advanced power generation systems, ranging from small fuel cell systems to commercial-scale power plants including the coal-fired, gasification-based FutureGen power and hydrogen production plant.

Zitney, S.E.

2006-11-01

231

Modeling and simulation of hydraulic system for a wheel loader using AMESim  

Microsoft Academic Search

Advancement of simulation capabilities made it possible to simulate any physical system before building the prototype to evaluate controls and performance test of components. Simulation results help to improve the design, reliability and operability, thereby reducing cost and time associated with the design significantly. This paper presents a simulation modeling way which used by software AMESim of hydraulic system for

Sung Hee Park; K. Alam; Young Man Jeong; Chang Don Lee; Soon Yong Yang

2009-01-01

232

Model-Based Integrated Simulation (MILAN).  

National Technical Information Service (NTIS)

The motivation for the Model-based Integrated Simulation (MILAN) project is to develop an extensible modeling, simulation, and design space exploration framework for the design of latency and energy efficient embedded systems for signal processing applica...

V. K. Prasanna C. S. Raghavendra A. Ledeczi

2005-01-01

233

Development of an advanced transmission line fault location system; Part II- Algorithm development and simulation  

SciTech Connect

This paper describes the solution techniques, system modeling considerations, and simulation studies performed as a part of the development of an advanced transmission line fault location system (AFLS) intended for use on the New York Power Authority's system. The Power Authority's Moses-Adirondack 230 kV lines were selected as a test bed for the study. A reduced model of the transmission system around the Moses-Adirondack lines was developed, and a number of Electromagnetic Transients Program (EMTP) cases run to establish simulated voltage and current information as fed to the fault location system. Sensitivity studies were performed to investigate the impact of various system models, hardware features, and system conditions on fault location accuracy.

Lawrence, D.J. (Power Technologies, Inc., Schenectady, NY (United States)); Cabeza, L.Z.; Hochberg, L.T. (New York Power Authority, New York, NY (United States))

1992-10-01

234

OXYGEN UTILIZATION IN ACTIVATED SLUDGE PLANTS: SIMULATION AND MODEL CALIBRATION  

EPA Science Inventory

The objective of the research described in the report is to apply recent advances in activated sludge process modeling to the simulation of oxygen utilization rates in full scale activated sludge treatment plants. This is accomplished by calibrating the International Association ...

235

Modeling and simulation of improved solar absorption cooling systems  

Microsoft Academic Search

Solar absorption cooling is economically unattractive compared to vapor compression cooling. This is due to the high cost and relatively low efficiency of the equipment. Improved configurations of the different components of the solar absorption system were studied, and techniques for their evaluation developed. The method consists of mathematic modeling and computer simulations. Three advanced absorption cycles, the absorption-resorption, double

Campos-Velarde

1983-01-01

236

A Real Time Simulation and Modeling of Flood Hazard  

Microsoft Academic Search

The increasing flash flood hazards in major cities like Kuala Lumpur have caused tremendous damages to the society and this requires more essential countermeasures to be implemented. With the advancement in 3D Computer Graphics and fluid simulation technologies, movie experts can now produce realistic visual effects for fluid objects such as water. This paper describes a study made to model

JASRUL NIZAM GHAZALI; AMIRRUDIN KAMSIN

237

Multiscale modeling and simulation for nano\\/micro materials  

Microsoft Academic Search

Continuum description and atomic description used to be two distinct methods in the community of modeling and simulations. Science and technology have become so advanced that our understanding of many physical phenomena involves the concepts of both. So our goal now is to build a bridge to make atoms and continua communicate with each other. Micromorphic theory (MMT) envisions a

Xianqiao Wang

2011-01-01

238

Modelling and Simulation of Central Receiver Solar Thermal Power Plants  

Microsoft Academic Search

The implementation of advanced control systems to optimize the overall performance of Central Receiver Solar Thermal Power Plants is nowadays a priority research line. The development of dynamic models for use in simulation and control of this kind of power plants is presented in this article, focused on the CESA-I solar plant of the Plataforma Solar de Almería (Southern Spain).

L. J. Yebra; M. Berenguel; S. Dormido; M. Romero

2005-01-01

239

SEMI Modeling and Simulation Roadmap  

SciTech Connect

With the exponential growth in the power of computing hardware and software, modeling and simulation is becoming a key enabler for the rapid design of reliable Microsystems. One vision of the future microsystem design process would include the following primary software capabilities: (1) The development of 3D part design, through standard CAD packages, with automatic design rule checks that guarantee the manufacturability and performance of the microsystem. (2) Automatic mesh generation, for 3D parts as manufactured, that permits computational simulation of the process steps, and the performance and reliability analysis for the final microsystem. (3) Computer generated 2D layouts for process steps that utilize detailed process models to generate the layout and process parameter recipe required to achieve the desired 3D part. (4) Science-based computational tools that can simulate the process physics, and the coupled thermal, fluid, structural, solid mechanics, electromagnetic and material response governing the performance and reliability of the microsystem. (5) Visualization software that permits the rapid visualization of 3D parts including cross-sectional maps, performance and reliability analysis results, and process simulation results. In addition to these desired software capabilities, a desired computing infrastructure would include massively parallel computers that enable rapid high-fidelity analysis, coupled with networked compute servers that permit computing at a distance. We now discuss the individual computational components that are required to achieve this vision. There are three primary areas of focus: design capabilities, science-based capabilities and computing infrastructure. Within each of these areas, there are several key capability requirements.

Hermina, W.L.

2000-10-02

240

Advances in Electromagnetic Modelling through High Performance Computing  

SciTech Connect

Under the DOE SciDAC project on Accelerator Science and Technology, a suite of electromagnetic codes has been under development at SLAC that are based on unstructured grids for higher accuracy, and use parallel processing to enable large-scale simulation. The new modeling capability is supported by SciDAC collaborations on meshing, solvers, refinement, optimization and visualization. These advances in computational science are described and the application of the parallel eigensolver Omega3P to the cavity design for the International Linear Collider is discussed.

Ko, K.; Folwell, N.; Ge, L.; Guetz, A.; Lee, L.; Li, Z.; Ng, C.; Prudencio, E.; Schussman, G.; Uplenchwar, R.; Xiao, L.; /SLAC

2006-03-29

241

Measurement and modeling of advanced coal conversion processes  

SciTech Connect

The overall objective of this program is the development of predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. This technology is important to reduce the technical and economic risks inherent in utilizing coal, a feedstock whose variable and often unexpected behavior presents a significant challenge. This program will merge significant advances made at Advanced Fuel Research, Inc. (AFR) in measuring and quantitatively describing the mechanisms in coal conversion behavior, with technology being developed at Brigham Young University (BYU) in comprehensive computer codes for mechanistic modeling of entrained-bed gasification. Additional capabilities in predicting pollutant formation will be implemented and the technology will be expanded to fixed-bed reactors. The foundation to describe coal-specific conversion behavior is AFR's Functional Group (FG) and Devolatilization, Vaporization, and Crosslinking (DVC) models, developed under previous and on-going METC sponsored programs. These models have demonstrated the capability to describe the time dependent evolution of individual gas species, and the amount and characteristics of tar and char. The combined FG-DVC model will be integrated with BYU's comprehensive two-dimensional reactor model, PCGC-2, which is currently the most widely used reactor simulation for combustion or gasification. Success in this program will be a major step in improving in predictive capabilities for coal conversion processes including: demonstrated accuracy and reliability and a generalized first principles'' treatment of coals based on readily obtained composition data. The progress during the fifteenth quarterly of the program is presented. 56 refs., 41 figs., 5 tabs.

Solomon, P.R.; Serio, M.A.; Hamblen, D.G. (Advanced Fuel Research, Inc., East Hartford, CT (USA)); Smoot, L.D.; Brewster, B.S. (Brigham Young Univ., Provo, UT (USA))

1990-01-01

242

Object-Oriented Quantum Cryptography Simulation Model  

Microsoft Academic Search

Quantum computation simulation has been a hot research topic recently and a few softwares used in research have been developed. Compared with these existed softwares and their approaches, this paper proposes an object oriented quantum cryptography simulation model. Furthermore, we also firstly integrate classical cryptography algorithms into this model. Finally, the advantages and disadvantages of this model over other simulation

Xiufeng Zhang; Qiaoyan Wen; Fuchen Zhu

2007-01-01

243

Automatic programming of AGVS simulation models  

Microsoft Academic Search

This paper presents a knowledge based modeling system that allows a manufacturing engineer who has very limited knowledge of simulation methodology to quickly and correctly, develop and run a simulation model of an automated guided vehicle system (AGVS). The modeling system is capable of guiding and assisting the engineer with a level of “expertise” comparable to a trained simulation specialist.

Mark K. Brazier; Robert E. Shannon

1987-01-01

244

Simulation and Modeling of Homogeneous, Compressed Turbulence.  

NASA Astrophysics Data System (ADS)

Low Reynolds number homogeneous turbulence undergoing low Mach number isotropic and one-dimensional compression has been simulated by numerically solving the Navier-Stokes equations. The numerical simulations were carried out on a CYBER 205 computer using a 64 x 64 x 64 mesh. A spectral method was used for spatial differencing and the second -order Runge-Kutta method for time advancement. A variety of statistical information was extracted from the computed flow fields. These include three-dimensional energy and dissipation spectra, two-point velocity correlations, one -dimensional energy spectra, turbulent kinetic energy and its dissipation rate, integral length scales, Taylor microscales, and Kolmogorov length scale. It was found that the ratio of the turbulence time scale to the mean-flow time scale is an important parameter in these flows. When this ratio is large, the flow is immediately affected by the mean strain in a manner similar to that predicted by rapid distortion theory. When this ratio is small, the flow retains the character of decaying isotropic turbulence initially; only after the strain has been applied for a long period does the flow accumulate a significant reflection of the effect of mean strain. In these flows, the Kolmogorov length scale decreases rapidly with increasing total strain, due to the density increase that accompanies compression. Results from the simulated flow fields were used to test one-point-closure, two-equation turbulence models. The two-equation models perform well only when the compression rate is small compared to the eddy turn-over rate. A new one-point-closure, three-equation turbulence model which accounts for the effect of compression is proposed. The new model accurately calculates four types of flows (isotropic decay, isotropic compression, one-dimensional compression, and axisymmetric expansion flows) for a wide range of strain rates.

Wu, Chung-Teh

245

BRITE II characterization and application to a new advanced flight motion simulator  

NASA Astrophysics Data System (ADS)

Hardware-in-the-loop testing has, for many years, been an integral part of the modeling and simulation efforts at the U.S. Army Aviation and Missile Command"s (AMCOM) Aviation and Missile Research, Engineering, and Development Center (AMRDEC). AMCOM"s history includes the development, characterization, and implementation of several unique technologies for the creation of synthetic environments in the visible and infrared regions and AMCOM has continued significant efforts in these areas. Recently, AMCOM has been testing and characterizing a new state-of-the-art resistor array projector and advanced flight motion simulator (FMS). This paper describes recent test and integration activities of the Honeywell BRITE II emitter array and its integration into an infrared scene projector (IRSP) compatible with a new Carco Flight Motion Simulator (FMS).

Beasley, David B.; Saylor, Daniel A.; Buford, James A., Jr.

2003-09-01

246

On land surface modeling in large-eddy simulations of atmospheric boundary layers  

Microsoft Academic Search

Since years, Large-Eddy simulation models (LES) serve as a virtual laboratory for atmospheric scientists. In recent years, advances in computer power have brought us to the point where simulations of large domains and diurnal cycles became feasible. Therefore, the coupling of LES with a land surface model (LSM) gained interest among the modeling community. At the same time, mesoscale models

C. van Heerwaarden; E. Bou-Zeid; J. Vila-Guerau Arellano

2010-01-01

247

Modelling and simulation of radiotherapy  

NASA Astrophysics Data System (ADS)

In this paper, models are described which have been developed to model both the way in which a population of cells respond to radiation and the way in which a population of patients respond to radiotherapy to assist the conduct of clinical trials in silico. Population balance techniques have been used to simulate the age distribution of tumour cells in the cell cycle. Sensitivity to radiation is not constant round the cell cycle and a single fraction of radiation changes the age distribution. Careful timing of further fractions of radiation can be used to maximize the damage delivered to the tumour while minimizing damage to normal tissue. However, tumour modelling does not necessarily predict patient outcome. A separate model has been established to predict the course of a brain cancer called glioblastoma multiforme (GBM). The model considers the growth of the tumour and its effect on the normal brain. A simple representation is included of the health status of the patient and hence the type of treatment offered. It is concluded that although these and similar models have a long way yet to be developed, they are beginning to have an impact on the development of clinical practice.

Kirkby, Norman F.

2007-02-01

248

Diesel engine emissions and combustion predictions using advanced mixing models applicable to fuel sprays  

Microsoft Academic Search

An advanced mixing model was applied to study engine emissions and combustion with different injection strategies ranging from multiple injections, early injection and grouped-hole nozzle injection in light and heavy duty diesel engines. The model was implemented in the KIVA-CHEMKIN engine combustion code and simulations were conducted at different mesh resolutions. The model was compared with the standard KIVA spray

Neerav Abani; Rolf D. Reitz

2010-01-01

249

Thermochemical modelling of advanced CANDU reactor fuel  

NASA Astrophysics Data System (ADS)

With an aging fleet of nuclear generating facilities, the imperative to limit the use of non-renewal fossil fuels and the inevitable need for additional electricity to power Canada's economy, a renaissance in the use of nuclear technology in Canada is at hand. The experience and knowledge of over 40 years of CANDU research, development and operation in Ontario and elsewhere has been applied to a new generation of CANDU, the Advanced CANDU Reactor (ACR). Improved fuel design allows for an extended burnup, which is a significant improvement, enhancing the safety and the economies of the ACR. The use of a Burnable Neutron Absorber (BNA) material and Low Enriched Uranium (LEU) fuel has created a need to understand better these novel materials and fuel types. This thesis documents a work to advance the scientific and technological knowledge of the ACR fuel design with respect to thermodynamic phase stability and fuel oxidation modelling. For the BNA material, a new (BNA) model is created based on the fundamental first principles of Gibbs energy minimization applied to material phase stability. For LEU fuel, the methodology used for the BNA model is applied to the oxidation of irradiated fuel. The pertinent knowledge base for uranium, oxygen and the major fission products is reviewed, updated and integrated to create a model that is applicable to current and future CANDU fuel designs. As part of this thesis, X-Ray Diffraction (XRD) and Coulombic Titration (CT) experiments are compared to the BNA and LEU models, respectively. From the analysis of the CT results, a number of improvements are proposed to enhance the LEU model and provide confidence in its application to ACR fuel. A number of applications for the potential use of these models are proposed and discussed. Keywords: CANDU Fuel, Gibbs Energy Mimimization, Low Enriched Uranium (LEU) Fuel, Burnable Neutron Absorber (BNA) Material, Coulometric Titration, X-Ray Diffraction

Corcoran, Emily Catherine

250

Advances in Rheumatoid Arthritis Animal Models  

PubMed Central

Experimental models of rheumatoid arthritis (RA) have contributed immensely to our understanding of the pathogenesis as well as the treatment of this debilitating autoimmune disease. Significant progress has been made in the past few years in defining the role of newer cytokines and regulatory T cells, of inflammation-mediated bone and cartilage damage, and of the cholinergic anti-inflammatory pathway in modulating the disease process in arthritis. Furthermore, new therapeutic targets, including specific tyrosine kinases and proteasome subunits have been explored. These advances offer renewed optimism for continued improvements in the management of RA.

Moudgil, Kamal D.; Kim, Peter; Brahn, Ernest

2013-01-01

251

Advanced thermal energy management: A thermal test bed and heat pipe simulation  

NASA Astrophysics Data System (ADS)

Work initiated on a common-module thermal test simulation was continued, and a second project on heat pipe simulation was begun. The test bed, constructed from surplus Skylab equipment, was modeled and solved for various thermal load and flow conditions. Low thermal load caused the radiator fluid, Coolanol 25, to thicken due to its temperature avoided by using a regenerator-heat-exchanger. Other possible solutions modeled include a radiator heater and shunting heat from the central thermal bus to the radiator. Also, module air temperature can become excessive with high avionics load. A second preoject concerning advanced heat pipe concepts was initiated. A program was written which calculates fluid physical properties, liquid and vapor pressure in the evaporator and condenser, fluid flow rates, and thermal flux. The program is directed to evaluating newer heat pipe wicks and geometries, especially water in an artery surrounded by six vapor channels. Effects of temperature, groove and slot dimensions, and wick properties are reported.

Barile, Ronald G.

1986-11-01

252

Modeling of Army Research Laboratory EMP simulators  

SciTech Connect

Models are required that permit the estimation of emitted field signatures from EMP simulators to design the simulator antenna structure, to establish the usable test volumes, and to estimate human exposure risk. This paper presents the capabilities and limitations of a variety of EMP simulator models useful to the Army's EMP survivability programs. Comparisons among frequency and time-domain models are provided for two powerful US Army Research Laboratory EMP simulators: AESOP (Army EMP Simulator Operations) and VEMPS II (Vertical EMP Simulator II).

Miletta, J.R.; Chase, R.J.; Luu, B.B. (Army Research Lab., Adelphi, MD (United States)); Williams, J.W.; Viverito, V.J. (Science Applications International Corp., Germantown, MD (United States))

1993-12-01

253

Advanced Atmospheric Transport Modeling for Emergency Response  

SciTech Connect

Local and regional weather forecasts are an important component of the Department of Energy's (DOE) Savannah River Site (SRS) response capabilities in the event of hazardous accidental releases to the atmosphere. The fate of radiological or chemical releases can be determined by providing winds and turbulence input to atmospheric transport models. The Weather Information and Display (WIND) system consists of a network of computers and instruments that collect meteorological data from towers situated throughout the 800 square kilometer site, display updated results every 15 minutes, and supplies real-time data to a suite of personal computer (PC) based Gaussian dispersion models for assessing downwind hazards. It has been the primary consequence assessment tool for emergency response for many years. Several years ago, the SRS began using an advanced three-dimensional numerical model, the Regional Atmospheric Modeling System (RAMS) as a source of local forecast data for the basic WIND system models. The information RAMS provides to these dispersion models is spatially homogeneous. However, recently a more complete utilization of the spatially inhomogeneous RAMS forecasts has been realized by using a three-dimensional stochastic Lagrangian particle dispersion model (LPDM) to advect and disperse particles representing pollutant mass in the atmosphere. The purpose of this paper is to discuss the design and implementation of LPDM for use on a PC for real-time emergency response applications at the SRS.

Buckley, R.L.

2002-06-24

254

Numerical Forming Simulations and Optimisation in Advanced Materials  

SciTech Connect

With the introduction of new materials as high strength steels, metastable steels and fibre reinforced composites, the need for advanced physically valid constitutive models arises. In finite deformation problems constitutive relations are commonly formulated in terms the Cauchy stress as a function of the elastic Finger tensor and an objective rate of the Cauchy stress as a function of the rate of deformation tensor. For isotropic materials models this is rather straightforward, but for anisotropic material models, including elastic anisotropy as well as plastic anisotropy, this may lead to confusing formulations. It will be shown that it is more convenient to define the constitutive relations in terms of invariant tensors referred to the deformed metric. Experimental results are presented that show new combinations of strain rate and strain path sensitivity. An adaptive through- thickness integration scheme for plate elements is developed, which improves the accuracy of spring back prediction at minimal costs. A procedure is described to automatically compensate the CAD tool shape numerically to obtain the desired product shape. Forming processes need to be optimized for cost saving and product improvement. Until recently, a trial-and-error process in the factory primarily did this optimization. An optimisation strategy is proposed that assists an engineer to model an optimization problem that suits his needs, including an efficient algorithm for solving the problem.

Huetink, J.; Boogaard, A. H. van den; Geijselears, H. J. M.; Meinders, T. [University of Twente, Faculty of Engineering Technology P.O.Box 217, 7500 AE Enschede (Netherlands)

2007-05-17

255

Numerical Forming Simulations and Optimisation in Advanced Materials  

NASA Astrophysics Data System (ADS)

With the introduction of new materials as high strength steels, metastable steels and fibre reinforced composites, the need for advanced physically valid constitutive models arises. In finite deformation problems constitutive relations are commonly formulated in terms the Cauchy stress as a function of the elastic Finger tensor and an objective rate of the Cauchy stress as a function of the rate of deformation tensor. For isotropic materials models this is rather straightforward, but for anisotropic material models, including elastic anisotropy as well as plastic anisotropy, this may lead to confusing formulations. It will be shown that it is more convenient to define the constitutive relations in terms of invariant tensors referred to the deformed metric. Experimental results are presented that show new combinations of strain rate and strain path sensitivity. An adaptive through- thickness integration scheme for plate elements is developed, which improves the accuracy of spring back prediction at minimal costs. A procedure is described to automatically compensate the CAD tool shape numerically to obtain the desired product shape. Forming processes need to be optimized for cost saving and product improvement. Until recently, a trial-and-error process in the factory primarily did this optimization. An optimisation strategy is proposed that assists an engineer to model an optimization problem that suits his needs, including an efficient algorithm for solving the problem.

Huétink, J.; van den Boogaard, A. H.; Geijselears, H. J. M.; Meinders, T.

2007-05-01

256

Physics and modeling of dopant diffusion for advanced device applications  

NASA Astrophysics Data System (ADS)

Physically based diffusion models have been developed to simulate dopant diffusion for advanced semiconductor device technology. Based on extensive experimental results and fundamental defect related kinetics, the diffusion models has been developed to include various diffusion species and defect reactions in order to simulate the complex dopant redistribution due to transient enhanced diffusion (TED). For next generation channel doping technology, the experiment and modeling of indium diffusion during high temperature rapid thermal annealing (RTA) was carried out. The diffusion of implanted indium is a combined effect of TED and thermal equilibrium diffusion. The implanted indium cannot be fully activated after RTA due to carrier freeze-out. A diffusion model was developed to describe the indium redistribution during RTA. The TED induced by ion implantation was extensively investigated for the phosphorus diffusion during low temperature furnace annealing. The TED of implanted phosphorus shows an initial decay at the early stage of annealing, and increases with increasing implant energy and dose. Dose loss of phosphorus was found during the TED period due to interface segregation. TED was shown to dominate the dose loss process. The Hybrid diffusion model including defect clustering and interface segregation effects was developed. The model accurately simulates the TED and dose loss of implanted phosphorus during low temperature annealing. The co-diffusion study for arsenic and boron was performed to understand the boron redistribution in the channel region due to the TED caused by the arsenic source/drain implant. The boron segregation in the arsenic profile is induced by the combined effects of junction electric field and TED during annealing. The segregation is driven by the TED caused by either ion implantation or arsenic deactivation. To simulate the co-diffusion phenomenon, dislocation and arsenic clustering kinetics and their interactions with point defects are included. Results show that arsenic deactivation causes additional boron segregation which affects channel doping profile greatly and degrades the device performance.

Chang, Ruey-Dar

257

Using an advanced vehicle simulator (ADVISOR) to guide hybrid vehicle propulsion system development  

SciTech Connect

An advanced vehicle simulator model called ADVISOR has been developed at the National Renewable Energy Laboratory to allow system-level analysis and trade-off studies of advanced vehicles. Because of ADVISOR`s fast execution speed and the open programming environment of MATLAB/Simulink, the simulator is ideally suited for doing parametric studies to map out the design space of potential high fuel economy vehicles (3X) consistent with the goals of the Partnership for New Generation of Vehicles (PNGV). Five separate vehicle configurations have been modeled including 3 lightweight vehicles (parallel, series, and conventional drivetrains) along with 2 vehicles with 1996 vehicle weights (parallel and conventional drivetrains). The sensitivity of each vehicle`s fuel economy to critical vehicle parameters is then examined and regions of interest for the vehicles mapped out through parametric studies. Using the simulation results for these vehicles, the effect of hybridization is isolated and analyzed and the trade-offs between series and parallel designs are illustrated.

Wipke, K.B.; Cuddy, M.R.

1996-08-01

258

Advances in using simulation to enhance military training  

Microsoft Academic Search

This paper provides a high-level overview of current applications of simulation in support of military training. Several examples are cited and described to give at least the 'flavor' of simulation applications in military training. The following topics are addressed: factors influencing the use of simulation in military training; simulation technology and capabilities; small unit and crew level applications of simulation

J. T. Roth

1997-01-01

259

Crashworthiness analysis using advanced material models in DYNA3D  

SciTech Connect

As part of an electric vehicle consortium, LLNL and Kaiser Aluminum are conducting experimental and numerical studies on crashworthy aluminum spaceframe designs. They have jointly explored the effect of heat treat on crush behavior and duplicated the experimental behavior with finite-element simulations. The major technical contributions to the state of the art in numerical simulation arise from the development and use of advanced material model descriptions for LLNL`s DYNA3D code. Constitutive model enhancements in both flow and failure have been employed for conventional materials such as low-carbon steels, and also for lighter weight materials such as aluminum and fiber composites being considered for future vehicles. The constitutive model enhancements are developed as extensions from LLNL`s work in anisotropic flow and multiaxial failure modeling. Analysis quality as a function of level of simplification of material behavior and mesh is explored, as well as the penalty in computation cost that must be paid for using more complex models and meshes. The lightweight material modeling technology is being used at the vehicle component level to explore the safety implications of small neighborhood electric vehicles manufactured almost exclusively from these materials.

Logan, R.W.; Burger, M.J.; McMichael, L.D. [Lawrence Livermore National Lab., CA (United States); Parkinson, R.D. [Kaiser Aluminum & Chemical Corp., Pleasanton, CA (United States). Center for Technology

1993-10-22

260

Verification and validation of simulation models  

Microsoft Academic Search

This paper surveys verification and validation of models, especially simulation models in operations research. For verification it discusses 1) general good programming practice (such as modular programming), 2) checking intermediate simulation outputs through tracing and statistical testing per module, 3) statistical testing of final simulation outputs against analytical results, and 4) animation. For validation it discusses 1) obtaining real-worl data,

Jack P. C. Kleijnen

1995-01-01

261

Integrated support environments for simulation modelling  

Microsoft Academic Search

The general concept of an integrated software support environment to enhance the productivity of the simulation modeller has motivated several groups to design and implement such environments. Underlying each such development is a perspective, implicit or explicit, of the methodology of simulation modelling. This paper rewews the experience of the Computer Aided Simulation Modellin8 (CASM)group at the London School of

David W. Balmer; Ray J. Paul

1990-01-01

262

ASPEN(Advanced System for Process Engineering) Simulation of a Fixed-Bed Integrated Gasification Combined-Cycle Power Plant.  

National Technical Information Service (NTIS)

A fixed-bed integrated gasification combined-cycle (IGCC) power plant has been modeled using the Advanced System for Process ENgineering (ASPEN). The ASPEN simulation is based on a conceptual design of a 509-MW IGCC power plant that uses British Gas Corpo...

K. R. Stone

1986-01-01

263

Ant Mobility Model Platform for Network Simulator  

Microsoft Academic Search

Various ad hoc routing algorithms were proposed to increase the performance in ad hoc network. In order to estimate the performance of routing algorithms, they always simulate in ad hoc network environment, and a mobility model is also used for network simulation. There are two types of mobility models: trace and synthetic models. Trace models are more accurate than synthetic

Hsien-chou Liao; Yi-wei Ting; Shih-hsuan Yen; Chou-Chen Yang

2004-01-01

264

Prospects for advanced RF theory and modeling  

SciTech Connect

This paper represents an attempt to express in print the contents of a rather philosophical review talk. The charge for the talk was not to summarize the present status of the field and what we can do, but to assess what we will need to do in the future and where the gaps are in fulfilling these needs. The objective was to be complete, covering all aspects of theory and modeling in all frequency regimes, although in the end the talk mainly focussed on the ion cyclotron range of frequencies (ICRF). In choosing which areas to develop, it is important to keep in mind who the customers for RF modeling are likely to be and what sorts of tasks they will need for RF to do. This occupies the first part of the paper. Then we examine each of the elements of a complete RF theory and try to identify the kinds of advances needed. (c) 1999 American Institute of Physics.

Batchelor, D. B. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States)

1999-09-20

265

Prospects for Advanced RF Theory and Modeling  

SciTech Connect

This paper represents an attempt to express in print the contents of a rather philosophical review talk. The charge for the talk was not to summarize the present status of the field and what we can do, but to assess what we will need to do in the future and where the gaps are in fulfilling these needs. The objective was to be complete, covering all aspects of theory and modeling in all frequency regimes, although in the end the talk mainly focussed on the ion cyclotron range of frequencies (ICRF). In choosing which areas to develop, it is important to keep in mind who the customers for RF modeling are likely to be and what sorts of tasks they will need for RF to do. This occupies the first part of the paper. Then we examine each of the elements of a complete RF theory and try to identify the kinds of advances needed.

Batchelor, D.B.

1999-04-12

266

Interactive Communication Systems Simulation Model (ICSSM) Extension.  

National Technical Information Service (NTIS)

The Interactive Communication System Simulation Model (ICSSM), developed for the Rome Air Development Center, is capable of simulating a point-to-point communication system including its functional elements, components, propagation effects, and transmissi...

I. Gerry M. Mammone W. D. Wade

1983-01-01

267

Phase Transformation Kinetics: Advanced Modeling Strategies  

NASA Astrophysics Data System (ADS)

Phase transformations in the solid state are often heterogeneous and can be described by concurring modes of nucleation, growth, and impingement. The classical Johnson-Mehl-Avrami-Kolmogorov-(JMAK-) model, although offering an easy-to-use description of the transformation kinetics, is limited to very specific cases of the transformation modes. Instead, a generalized modular model of phase transformation kinetics can be proposed that provides a flexible formalism adaptable to various modes of nucleation, growth, and impingement. Due to its large versatility, the modular model approach can be easily applied for characterization of phase transformation kinetics beyond the scope of classical JMAK(-type) modeling. Three different strategies recently employed for such advanced modeling are presented: (I) deliberate variation of the nucleation mode upon crystallization of an Fe-Ni-B metallic glass in order to determine separate activation energies for nucleation and growth, (II) incorporation of specific, dedicated modes for nucleation and growth kinetics for the allotropic hcp-fcc transformation in cobalt introducing driving-force-dependent rates of transformation, and (III) implementation of quantitative microstructural data for the description of the precipitation kinetics in a supersaturated CuCo alloy.

Rheingans, B.; Mittemeijer, E. J.

2013-09-01

268

SPARC - A Simulation Model for Electrical Charges.  

National Technical Information Service (NTIS)

A simulation model for electrical discharges which is capable of modeling streamer and leader propagation over long distances is described. The model couples an electrostatic field solver, a chemistry package, and a package for solving the hydrodynamic eq...

D. F. Gordon P. Sprangle S. Slinker R. Fernsler M. Lampe

2006-01-01

269

Advances in HTGR fuel performance models  

SciTech Connect

Fuel performance models based on empirical evidence are used to predict particle failure and fission product release in the design of high-temperature gas-cooled reactors (HTGRs). Advances in HTGR fuel performance models have improved the agreement between observed and predicted performance and contributed to an enhanced position of the HTGR with regard to investment risk and passive safety. Heavy metal contamination is the source of about 55% of the circulating activity in the HTGR during normal operation, and the remainder comes primarily from particles which failed because of defective or missing buffer coatings. These failed particles make up about 5 x 10/sup -4/ fraction of the total core inventory. In addition to prediction of fuel performance during normal operation, the models are used to determine fuel failure and fission product release during core heat-up accident conditions. The mechanistic nature of the models, which incorporate all important failure modes, permits the prediction of performance from the relatively modest accident temperatures of a passively safe HTGR to the much more severe accident conditions of the larger 2240-MW(t) HTGR.

Stansfield, O.M.; Goodin, D.T.; Hanson, D.L.; Turner, R.F.

1985-02-01

270

Advanced modeling of active control of fan noise for ultra high bypass turbofan engines  

Microsoft Academic Search

An advanced model of active control of fan noise for ultra high bypass turbofan engines has been developed. This model is based on a boundary integral equation method and simulates the propagation, radiation and control of the noise generated by an engine fan surrounded by a duct of finite length and cylindrical shape, placed in a uniform flow. Control sources,

Florence Vanel Hutcheson

1999-01-01

271

USER'S GUIDE FOR THE ADVANCED STATISTICAL TRAJECTORY REGIONAL AIR POLLUTION (ASTRAP) MODEL  

EPA Science Inventory

The Advanced Statistical Trajectory Regional Air Pollution (ASTRAP) model simulates long-range, long-term transport and deposition of air pollutants, primarily oxides of sulfur and nitrogen. The ASTRAP model is designed to combine ease of exercise with an appropriate detail of ph...

272

Advanced Plasticity Models Applied to Recent Shock Data on Beryllium  

NASA Astrophysics Data System (ADS)

Recent plate impact experiments with pressures from 2 to 20 GPa have been performed on vacuum hot-pressed S-200F Beryllium. This hexagonal close-packed (HCP) metal shows significant plasticity effects. To examine the validity of advanced plasticity models in the shock regime, the plate impact experiments were modeled using a Lagrangian hydrocode. Two constitutive strength (plasticity) models, the Preston-Tonks-Wallace (PTW) and Mechanical Threshold Stress (MTS) models, were calibrated using the same extensive set of quasi-static and Hopkinson bar data taken at temperatures from 77K to 873K and strain rates from 0.001/sec to 4300/sec. In spite of being calibrated on the same data, the two models give noticeably different results when comparing with the experimentally measured wave profiles. Neither model is unequivocally superior, with each matching some aspects of the data better. The reasons for the differences are explored and discussed. Differences between the two models are particularly evident during reverse loading upon shock release, which is also examined. The performance of simpler plasticity models than PTW or MTS in simulating the impact tests is also presented for reference.

Prime, Michael; Adams, Chris; Chen, Shuh-Rong

2011-06-01

273

Use of Advanced Meteorological Model Output for Coastal Ocean Modeling in Puget Sound  

SciTech Connect

It is a great challenge to specify meteorological forcing in estuarine and coastal circulation modeling using observed data because of the lack of complete datasets. As a result of this limitation, water temperature is often not simulated in estuarine and coastal modeling, with the assumption that density-induced currents are generally dominated by salinity gradients. However, in many situations, temperature gradients could be sufficiently large to influence the baroclinic motion. In this paper, we present an approach to simulate water temperature using outputs from advanced meteorological models. This modeling approach was applied to simulate annual variations of water temperatures of Puget Sound, a fjordal estuary in the Pacific Northwest of USA. Meteorological parameters from North American Region Re-analysis (NARR) model outputs were evaluated with comparisons to observed data at real-time meteorological stations. Model results demonstrated that NARR outputs can be used to drive coastal ocean models for realistic simulations of long-term water-temperature distributions in Puget Sound. Model results indicated that the net flux from NARR can be further improved with the additional information from real-time observations.

Yang, Zhaoqing; Khangaonkar, Tarang; Wang, Taiping

2011-06-01

274

MedModel: healthcare specific simulation software  

Microsoft Academic Search

Since its release in 1993, MedModel has continued to make substantial strides in the evolution of healthcare simulation software. Until its arrival, the complex interdependencies and extreme number of variable outcomes exhibited by the ordinary healthcare system restricted the use of simulation to large forecasting or trend analysis models. MedModel was specifically designed to be simple to use and tailorable

Jeffrey B. Schulz

1995-01-01

275

MedModel-healthcare specific simulation software  

Microsoft Academic Search

Since its release in 1993, MedModel has continued to make substantial strides in the evolution of healthcare simulation software. Until its arrival, the complex interdependencies and extreme number of variable outcomes exhibited by the ordinary healthcare system restricted the use of simulation to large forecasting or trend analysis models. MedModel was specifically designed to be simple to use and tailorable

J. B. Schulz

1995-01-01

276

A Data - Integrated Nurse Activity Simulation Model  

Microsoft Academic Search

This research develops a data-integrated approach for constructing simulation models based on a real data set provided by Baylor Regional Medical Center (Baylor) in Grapevine, Texas. Tree-based models and kernel density estimation were utilized to extract important knowledge from the data for the simulation. Classification and Regression Tree model, a data mining tool for prediction and classification, was used to

Durai Sundaramoorthi; Victoria C. P. Chen; Seoung B. Kim; Jay M. Rosenberger; Deborah F. Buckley-Behan

2006-01-01

277

Monte Carlo simulations to advance characterisation of landmines by pulsed fast\\/thermal neutron analysis  

Microsoft Academic Search

The performance of a detection system based on the pulsed fast\\/thermal neutron analysis technique was assessed using Monte Carlo simulations. The aim was to develop and implement simulation methods, to support and advance the data analysis techniques of the characteristic ?-ray spectra, potentially leading to elemental characterisation of innocuous objects using the full spectrum analysis (FSA) approach. The simulations were

C. Rigollet

2004-01-01

278

Improving the aircraft design process using Web-based modeling and simulation  

Microsoft Academic Search

Designing and developing new aircraft systems is time-consuming and expensive. Computational simulation is a promising means for reducing design cycle times, but requires a flexible software environment capable of integrating advanced multidisciplinary and multifidelity analysis methods, dynamically managing data across heterogeneous computing platforms, and distributing computationally complex tasks. Web-based simulation, with its emphasis on collaborative composition of simulation models, distributed

John A. Reed; Gregory J. Follen; Abdollah A. Afjeh

2000-01-01

279

Survey of models/simulations at RADC  

NASA Astrophysics Data System (ADS)

A survey was conducted to evaluate the current state of the art and technology of model/simulation capabilities at Rome Air Development Center, Griffiss AFB, NY. This memo presents a tabulation of 28 such models/simulations. These models/simulations are being used within RADC in the development and evaluations of Command, Control, Communications and Intelligence (C3I) technology. The results of this survey are incorporated in this memo.

Denz, M. L.

1982-11-01

280

Advances in animal models of drug addiction.  

PubMed

Drug addiction is a syndrome of impaired response inhibition and salience attribution, which involves a complex neurocircuitry underlying drug reinforcement, drug craving, and compulsive drug-seeking and drug-taking behaviors despite adverse consequences. The concept of disease stages with transitions from acute rewarding effects to early- and end-stage addiction has had an important impact on the design of nonclinical animal models. This chapter reviews the main advances in nonclinical paradigms that aim to at model (1) positive and negative reinforcing effects of addictive drugs; (2) relapse to drug-seeking behavior; (3) reconsolidation of drug cue memories, and (4) compulsive/impulsive drug intake. In addition, recent small animal neuroimaging studies and invertebrate models will be briefly discussed (see also Bifone and Gozzi, Animal models of ADHD, 2011). Continuous improvement in modeling drug intake, craving, withdrawal symptoms, relapse, and comorbid psychiatric associations is a necessary step to better understand the etiology of the disease and to ultimately foster the discovery, validation and optimization of new efficacious pharmacotherapeutic approaches. The modeling of specific subprocesses or constructs that address clinically defined criteria will ultimately increase our understanding of the disease as a whole. Future research will have to address the questions of whether some of these constructs can be reliably used as outcome measures to assess the effects of a treatment in clinical settings, whether changes in those measures can be a target of therapeutic efforts, and whether they relate to biological markers of traits such as impulsivity, which contribute to increased drug-seeking and may predict binge-like patterns of drug intake. PMID:21225413

Heidbreder, Christian

2011-01-01

281

Kinetic Modeling of the Advanced Plasma Source  

NASA Astrophysics Data System (ADS)

Plasma ion assisted-deposition (PIAD) is a well-established technology for the creation of high quality coatings on mirrors, lenses, and other optical devices. This paper investigates the Advanced Plasma Source (APS), a plasma beam source employed for PIAD. A field enhanced glow discharge generates a radially expanding plasma flow with an ion energy of about 80 - 120,V. Charge exchange collions with the neutral background gas (pressure 0.1,a and below) produce a cold secondary plasma which expands as well. A hybrid model is developed which consists of a drift-kinetic description of the magnetized electrons, coupled to a simplified Boltzmann equation for the primary ions and fluid-dynamic representation of the secondary ions. All results compare well to experiments conducted at a commercial APS system.

Schroeder, Benjamin; Brinkmann, Ralf Peter; Harhausen, Jens; Ohl, Andreas

2011-11-01

282

Software Platform Evaluation - Verifiable Fuel Cycle Simulation (VISION) Model  

SciTech Connect

The purpose of this Software Platform Evaluation (SPE) is to document the top-level evaluation of potential software platforms on which to construct a simulation model that satisfies the requirements for a Verifiable Fuel Cycle Simulation Model (VISION) of the Advanced Fuel Cycle (AFC). See the Software Requirements Specification for Verifiable Fuel Cycle Simulation (VISION) Model (INEEL/EXT-05-02643, Rev. 0) for a discussion of the objective and scope of the VISION model. VISION is intended to serve as a broad systems analysis and study tool applicable to work conducted as part of the AFCI (including costs estimates) and Generation IV reactor development studies. This document will serve as a guide for selecting the most appropriate software platform for VISION. This is a “living document” that will be modified over the course of the execution of this work.

J. J. Jacobson; D. E. Shropshire; W. B. West

2005-11-01

283

RAM simulation model for SPH/RSV systems  

SciTech Connect

The US Army`s Project Manager, Crusader is sponsoring the development of technologies that apply to the Self-Propelled Howitzer (SPH), formerly the Advanced Field Artillery System (AFAS), and Resupply Vehicle (RSV), formerly the Future Armored Resupply Vehicle (FARV), weapon system. Oak Ridge National Laboratory (ORNL) is currently performing developmental work in support of the SPH/PSV Crusader system. Supportive analyses of reliability, availability, and maintainability (RAM) aspects were also performed for the SPH/RSV effort. During FY 1994 and FY 1995 OPNL conducted a feasibility study to demonstrate the application of simulation modeling for RAM analysis of the Crusader system. Following completion of the feasibility study, a full-scale RAM simulation model of the Crusader system was developed for both the SPH and PSV. This report provides documentation for the simulation model as well as instructions in the proper execution and utilization of the model for the conduct of RAM analyses.

Schryver, J.C.; Primm, A.H.; Nelson, S.C.

1995-12-31

284

Hydrological Simulation of Flood Events At Large Basins Using Distributed Modelling  

Microsoft Academic Search

Recent advances in technology allows to the scientist community advance in new pro- cedures in order to reduce the risk associated to flood events. A conceptual distributed model has been implemented to simulate the hydrological processes involved during floods. The model has been named TETIS. The basin is divided into rectangular cells, all of them connected according to the network

J. Vélez; I. Vélez; M. Puricelli; F. Francés

2002-01-01

285

Advanced virtual energy simulation training and research: IGCC with CO2 capture power plant  

SciTech Connect

In this presentation, we highlight the deployment of a real-time dynamic simulator of an integrated gasification combined cycle (IGCC) power plant with CO{sub 2} capture at the Department of Energy's (DOE) National Energy Technology Laboratory's (NETL) Advanced Virtual Energy Simulation Training and Research (AVESTARTM) Center. The Center was established as part of the DOE's accelerating initiative to advance new clean coal technology for power generation. IGCC systems are an attractive technology option, generating low-cost electricity by converting coal and/or other fuels into a clean synthesis gas mixture in a process that is efficient and environmentally superior to conventional power plants. The IGCC dynamic simulator builds on, and reaches beyond, conventional power plant simulators to merge, for the first time, a 'gasification with CO{sub 2} capture' process simulator with a 'combined-cycle' power simulator. Fueled with coal, petroleum coke, and/or biomass, the gasification island of the simulated IGCC plant consists of two oxygen-blown, downward-fired, entrained-flow, slagging gasifiers with radiant syngas coolers and two-stage sour shift reactors, followed by a dual-stage acid gas removal process for CO{sub 2} capture. The combined cycle island consists of two F-class gas turbines, steam turbine, and a heat recovery steam generator with three-pressure levels. The dynamic simulator can be used for normal base-load operation, as well as plant start-up and shut down. The real-time dynamic simulator also responds satisfactorily to process disturbances, feedstock blending and switchovers, fluctuations in ambient conditions, and power demand load shedding. In addition, the full-scope simulator handles a wide range of abnormal situations, including equipment malfunctions and failures, together with changes initiated through actions from plant field operators. By providing a comprehensive IGCC operator training system, the AVESTAR Center is poised to develop a workforce well-prepared to operate and control commercial-scale gasification-based power plants capable of 90% pre-combustion CO{sub 2} capture and compression, as well as low sulfur, mercury, and NOx emissions. With additional support from the NETL-Regional University Alliance (NETL-RUA), the Center will educate and train engineering students and researchers by providing hands-on 'learning by operating' experience The AVESTAR Center also offers unique collaborative R&D opportunities in high-fidelity dynamic modeling, advanced process control, real-time optimization, and virtual plant simulation. Objectives and goals are aimed at safe and effective management of power generation systems for optimal efficiency, while protecting the environment. To add another dimension of realism to the AVESTAR experience, NETL will introduce an immersive training system with innovative three-dimensional virtual reality technology. Wearing a stereoscopic headset or eyewear, trainees will enter an interactive virtual environment that will allow them to move freely throughout the simulated 3-D facility to study and learn various aspects of IGCC plant operation, control, and safety. Such combined operator and immersive training systems go beyond traditional simulation and include more realistic scenarios, improved communication, and collaboration among co-workers.

Zitney, S.; Liese, E.; Mahapatra, P.; Bhattacharyya, D.; Provost, G.

2011-01-01

286

Sensitivity of an ecological model to soil moisture simulations from two different hydrological models  

Microsoft Academic Search

Summary  Although advanced land surface schemes have been developed in the past decade, many biosphere models still use the simple\\u000a bucket model, partly due to its efficiency when it is coupled with an CGCM model. In this paper, we use a sophisticated land\\u000a surface model, the Simulator for Hydrology and Energy Exchange at the Land Surface (SHEELS), including an explicit vegetation

D. Ren; L. M. Leslie; D. J. Karoly

2008-01-01

287

Verification, validation and accreditation of simulation models  

Microsoft Academic Search

The paper discusses verification, validation, and accreditation of simulation models. The different approaches to deciding model validity are presented; how model verification and validation relate to the model development process are discussed; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are described; ways to document results are given; a recommended procedure is presented;

Robert G. Sargent

2000-01-01

288

Evaluating uncertainty in stochastic simulation models  

SciTech Connect

This paper discusses fundamental concepts of uncertainty analysis relevant to both stochastic simulation models and deterministic models. A stochastic simulation model, called a simulation model, is a stochastic mathematical model that incorporates random numbers in the calculation of the model prediction. Queuing models are familiar simulation models in which random numbers are used for sampling interarrival and service times. Another example of simulation models is found in probabilistic risk assessments where atmospheric dispersion submodels are used to calculate movement of material. For these models, randomness comes not from the sampling of times but from the sampling of weather conditions, which are described by a frequency distribution of atmospheric variables like wind speed and direction as a function of height above ground. A common characteristic of simulation models is that single predictions, based on one interarrival time or one weather condition, for example, are not nearly as informative as the probability distribution of possible predictions induced by sampling the simulation variables like time and weather condition. The language of model analysis is often general and vague, with terms having mostly intuitive meaning. The definition and motivations for some of the commonly used terms and phrases offered in this paper lead to an analysis procedure based on prediction variance. In the following mathematical abstraction the authors present a setting for model analysis, relate practical objectives to mathematical terms, and show how two reasonable premises lead to a viable analysis strategy.

McKay, M.D.

1998-02-01

289

Advances in swine biomedical model genomics.  

PubMed

This review is a short update on the diversity of swine biomedical models and the importance of genomics in their continued development. The swine has been used as a major mammalian model for human studies because of the similarity in size and physiology, and in organ development and disease progression. The pig model allows for deliberately timed studies, imaging of internal vessels and organs using standard human technologies, and collection of repeated peripheral samples and, at kill, detailed mucosal tissues. The ability to use pigs from the same litter, or cloned or transgenic pigs, facilitates comparative analyses and genetic mapping. The availability of numerous well defined cell lines, representing a broad range of tissues, further facilitates testing of gene expression, drug susceptibility, etc. Thus the pig is an excellent biomedical model for humans. For genomic applications it is an asset that the pig genome has high sequence and chromosome structure homology with humans. With the swine genome sequence now well advanced there are improving genetic and proteomic tools for these comparative analyses. The review will discuss some of the genomic approaches used to probe these models. The review will highlight genomic studies of melanoma and of infectious disease resistance, discussing issues to consider in designing such studies. It will end with a short discussion of the potential for genomic approaches to develop new alternatives for control of the most economically important disease of pigs, porcine reproductive and respiratory syndrome (PRRS), and the potential for applying knowledge gained with this virus for human viral infectious disease studies. PMID:17384736

Lunney, Joan K

2007-02-10

290

Model Following Control System Design: Preliminary ATTAS in-Flight Simulation Test Results.  

National Technical Information Service (NTIS)

The preliminary Advanced Technologies Testing Aircraft System (ATTAS) inflight simulation flight test results of the model following flight control system are described. A major portion of the current effort was directed towards estimating the time delays...

S. Chetty F. Henschel

1990-01-01

291

Clinicopathologic Characteristics and Prognosis of Advanced Gastric Cancer Simulating Early Gastric Cancer  

PubMed Central

Background Although the clinicopathologic features and prognosis of Borrmann type advanced gastric cancer has been well characterized, those of advanced gastric cancer simulating early gastric cancer (AGC simulating EGC) still remains unclear. Methods We reviewed 1985 gastric cancer patients who had undergone gastrectomy at our hospital to determine the clinicopathologic characteristics, susceptible sites for lymph node metastasis, and prognosis of AGC simulating EGC in comparison with Borrmann type advanced gastric cancer. Results Among 102 patients with AGC simulating EGC, 100 patients (98%) had tumors with depressed type appearance. The frequencies of serosal invasion, lymph node metastasis, lymphatic vessel invasion, blood vessel invasion, and liver metastasis were significantly lower in AGC simulating EGC than in Borrmann type tumors. The prognosis of AGC simulating EGC was significantly better than that of the Borrmann type tumors. Multivariate analysis indicated that the gross appearance was an independent prognostic factor. In patients with AGC simulating EGC which invaded to the the muscularis propria (MP), most lymph node metastasis was restricted with the perigastric lymph nodes (1st-titer lymph nodes) and lymph node metastasis to 2nd-titer lymph nodes was only observed at station 8a. Conclusion AGC simulating EGC is less advanced in comparison with Borrmann type advanced gastric cancer. Based on the results of susceptible sites for lymph node metastasis in the current study, limited lymph node dissection could be indicated for AGC simulating EGC whose depth of invasion is MP.

Saito, Hiroaki; Miyatani, Kozo; Takaya, Seigo; Matsunaga, Tomoyuki; Fukumoto, Yoji; Osaki, Tomohiro; Wakatsuki, Toshiro; Ikeguchi, Masahide

2013-01-01

292

Advancement of DOE's EnergyPlus Building Energy Simulation Payment  

SciTech Connect

EnergyPlus{sup TM} is a new generation computer software analysis tool that has been developed, tested, and commercialized to support DOEâ??s Building Technologies (BT) Program in terms of whole-building, component, and systems R&D (http://www.energyplus.gov). It is also being used to support evaluation and decision making of zero energy building (ZEB) energy efficiency and supply technologies during new building design and existing building retrofits. The 5-year project was managed by the National Energy Technology Laboratory and was divided into 5 budget period between 2006 and 2011. During the project period, 11 versions of EnergyPlus were released. This report summarizes work performed by an EnergyPlus development team led by the University of Central Floridaâ??s Florida Solar Energy Center (UCF/FSEC). The team members consist of DHL Consulting, C. O. Pedersen Associates, University of Illinois at Urbana-Champaign, Oklahoma State University, GARD Analytics, Inc., and WrightSoft Corporation. The project tasks involved new feature development, testing and validation, user support and training, and general EnergyPlus support. The team developed 146 new features during the 5-year period to advance the EnergyPlus capabilities. Annual contributions of new features are 7 in budget period 1, 19 in period 2, 36 in period 3, 41 in period 4, and 43 in period 5, respectively. The testing and validation task focused on running test suite and publishing report, developing new IEA test suite cases, testing and validating new source code, addressing change requests, and creating and testing installation package. The user support and training task provided support for users and interface developers, and organized and taught workshops. The general support task involved upgrading StarTeam (team sharing) software and updating existing utility software. The project met the DOE objectives and completed all tasks successfully. Although the EnergyPlus software was enhanced significantly under this project, more enhancements are needed for further improvement to ensure that EnergyPlus is able to simulate the latest technologies and perform desired HAVC system operations for the development of next generation HVAC systems. Additional development will be performed under a new 5-year project managed by the National Renewable Energy Laboratory.

Lixing Gu; Don Shirey; Richard Raustad; Bereket Nigusse; Chandan Sharma; Linda Lawrie; Rich Strand; Curt Pedersen; Dan Fisher; Edwin Lee; Mike Witte; Jason Glazer; Chip Barnaby

2011-03-31

293

Technology evaluation, assessment, modeling, and simulation: the TEAMS capability  

NASA Astrophysics Data System (ADS)

The United States Marine Corps' Technology Evaluation, Assessment, Modeling and Simulation (TEAMS) capability, located at the Naval Surface Warfare Center in Dahlgren Virginia, provides an environment for detailed test, evaluation, and assessment of live and simulated sensor and sensor-to-shooter systems for the joint warfare community. Frequent use of modeling and simulation allows for cost effective testing, bench-marking, and evaluation of various levels of sensors and sensor-to-shooter engagements. Interconnectivity to live, instrumented equipment operating in real battle space environments and to remote modeling and simulation facilities participating in advanced distributed simulations (ADS) exercises is available to support a wide- range of situational assessment requirements. TEAMS provides a valuable resource for a variety of users. Engineers, analysts, and other technology developers can use TEAMS to evaluate, assess and analyze tactical relevant phenomenological data on tactical situations. Expeditionary warfare and USMC concept developers can use the facility to support and execute advanced warfighting experiments (AWE) to better assess operational maneuver from the sea (OMFTS) concepts, doctrines, and technology developments. Developers can use the facility to support sensor system hardware, software and algorithm development as well as combat development, acquisition, and engineering processes. Test and evaluation specialists can use the facility to plan, assess, and augment their processes. This paper presents an overview of the TEAMS capability and focuses specifically on the technical challenges associated with the integration of live sensor hardware into a synthetic environment and how those challenges are being met. Existing sensors, recent experiments and facility specifications are featured.

Holland, Orgal T.; Stiegler, Robert L.

1998-08-01

294

Simulation model evolution: a strategic tool for model planning  

Microsoft Academic Search

Most simulation models evolve over time through a number of different metamorphic states. These states are typical to most simulation efforts within a specific simulation category (i.e. health care, military, material handling etc.). Using a cursory SWOT (strengths, weaknesses, opportunities, threats) analysis approach, this paper seeks to define the states as they occur in a typical automated material handling simulation

Todd Hunter

1994-01-01

295

Coupled neutronics-thermal hydraulics model of Advanced Heavy Water Reactor for control system studies  

Microsoft Academic Search

A coupled neutronics-thermal hydraulics model of advanced heavy water reactor (AHWR) which can be used for control system studies, simulation etc. is presented in this paper. A nodal model is developed for core neutronics and a simple two-phase thermal hydraulics model is developed from first principles. Neutronics-thermal hydraulics coupling is achieved through the void reactivity feedback model. Selection of a

S. R. Shimjith; A. P. Tiwari; B. Bandyopadhyay

2008-01-01

296

Advanced Neutron Source Dynamic Model (ANSDM) code description and user guide  

SciTech Connect

A mathematical model is designed that simulates the dynamic behavior of the Advanced Neutron Source (ANS) reactor. Its main objective is to model important characteristics of the ANS systems as they are being designed, updated, and employed; its primary design goal, to aid in the development of safety and control features. During the simulations the model is also found to aid in making design decisions for thermal-hydraulic systems. Model components, empirical correlations, and model parameters are discussed; sample procedures are also given. Modifications are cited, and significant development and application efforts are noted focusing on examination of instrumentation required during and after accidents to ensure adequate monitoring during transient conditions.

March-Leuba, J.

1995-08-01

297

Measurement and modeling of advanced coal conversion processes. Annual report, October 1990--September 1991  

SciTech Connect

The overall objective of this program is the development of predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. This program will merge significant advances made in measuring and quantitatively describing the mechanisms in coal conversion behavior. Comprehensive computer codes for mechanistic modeling of entrained-bed gasification. Additional capabilities in predicting pollutant formation will be implemented and the technology will be expanded to fixed-bed reactors.

Solomon, P.R.; Serio, M.A.; Hamblen, D.G.; Smoot, L.D.; Brewster, B.S. [Advanced Fuel Research, Inc., East Hartford, CT (United States)]|[Brigham Young Univ., Provo, UT (United States)

1991-12-31

298

Verification and validation of simulation models  

Microsoft Academic Search

In this paper we discuss verification and validation of simulation models. Four different approaches to deciding model validity are described; two different paradigms that relate verification and validation to the model development process are presented; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are discussed; a way to document results is given; a

Robert G. Sargent

2003-01-01

299

On the utility of graphics cards to perform massively parallel simulation of advanced Monte Carlo methods  

PubMed Central

We present a case-study on the utility of graphics cards to perform massively parallel simulation of advanced Monte Carlo methods. Graphics cards, containing multiple Graphics Processing Units (GPUs), are self-contained parallel computational devices that can be housed in conventional desktop and laptop computers and can be thought of as prototypes of the next generation of many-core processors. For certain classes of population-based Monte Carlo algorithms they offer massively parallel simulation, with the added advantage over conventional distributed multi-core processors that they are cheap, easily accessible, easy to maintain, easy to code, dedicated local devices with low power consumption. On a canonical set of stochastic simulation examples including population-based Markov chain Monte Carlo methods and Sequential Monte Carlo methods, we nd speedups from 35 to 500 fold over conventional single-threaded computer code. Our findings suggest that GPUs have the potential to facilitate the growth of statistical modelling into complex data rich domains through the availability of cheap and accessible many-core computation. We believe the speedup we observe should motivate wider use of parallelizable simulation methods and greater methodological attention to their design.

Lee, Anthony; Yau, Christopher; Giles, Michael B.; Doucet, Arnaud; Holmes, Christopher C.

2011-01-01

300

Multi-agent-based space information interaction simulation model  

NASA Astrophysics Data System (ADS)

Space information interaction process is so complex, distributed and intelligent that we have great difficulties in carrying through the advanced concept technology demonstration for it. To solve the problem, multi-agent-based modeling and simulation technology is applied to space warfare domain. By setting up the mapping from space warfare system's members to respective agents, the architecture of a distributed multi-agent system is designed and its control functions framework is discussed in this paper. As the farther analysis for the system's application, agent model is studied, and the inter-agent problems of task decomposition and task allocation are furthermore discussed. The established distributed simulation system model can be used to understand the external, complicated and intelligent space information interaction resources application activities and can afford advantage for realizing the dynamic space warfare action simulation.

Li, Xiong; Liu, Degang; Cong, Hua

2005-11-01

301

Implementation of a Free-Vortex Wake Model in Real-Time Simulation of Rotorcraft  

Microsoft Academic Search

Free-vortex wake models are capable of providing an accurate and physically detailed representation of the main rotor wake for flight dynamics simulation. Recent advances in computingpowerandefficientalgorithmshavemadeitfeasibletousefreewakesforreal-time simulation. The CHARM free-vortex wake model was integrated with the GENHEL flight dynamics simulation of the UH-60A helicopter. A high fidelity wake model was defined by increasing the spatial and temporal resolution of the

Joseph F. Horn; Derek O. Bridges; Sarma Rani; Daniel Wachspress

2006-01-01

302

System simulation model of lottery sales  

Microsoft Academic Search

Based on system analysis principles, by reviewing relevant theory and literature, got the lottery sales impact factor system. Draw out the lottery sales system causal feedback map by using system dynamics, and on this basis, established the lottery sales system flow diagram simulation model. This model can be used to simulate and analyze the various factors of the lottery sales;

Yu Mingnan; Li Huanming

2010-01-01

303

Oil Market Simulation model user's manual.  

National Technical Information Service (NTIS)

The Oil Market Simulation (OMS) model is a LOTUS 1-2-3 spreadsheet that simulates the world oil market. OMS is an annual model that projects the world oil market through the year 2010 from a data base that begins in 1979. The geographic coverage includes ...

1991-01-01

304

Crowd Control Modeling and Simulation Research Plan.  

National Technical Information Service (NTIS)

The purpose of this document is to lay out a plan for research on Crowd Control Modeling and Simulation. Models and simulations that predict or describe crowd behavior do not exist at the present time in a form that could be used to describe the dynamics ...

D. Scholl P. Mason L. Sayegh R. Constable A. Tijerina

2003-01-01

305

Iron Resources and Oceanic Nutrients: Advancement of Global Environment Simulations  

NASA Astrophysics Data System (ADS)

The concept of a single factor limiting plankton blooms, is presently giving way to co-limitation by light, and the nutrients N, P, Si and Fe. Primary production, export into the deep sea, and CO2 uptake from the atmosphere together form the 'biological pump' in Ocean Biogeochemical Climate Models (OBCM's). Thus far OBCM's assume just one limiting nutrient (P) and one universal phytoplankton species, for C budgets and CO2 exchange. New realistic OBCM's are being developed for budgeting and exchanges of both CO2 and DMS, implementing (i) co-limitation by 4 nutrients of 5 major taxonomic classes of phytoplankton, (ii) DMS(P) pathways, (iii) global iron cycling, (iv) chemical forms of iron and (v) iron supply into surface waters. The new OBCM's will predict realistic climate scenario's, notably climatic feedbacks on oceanic biogeochemistry. IRONAGES is a European consortium of twelve institutes and is coordinated by Royal NIOZ. Input from below of iron from anoxic sediments of coastal margins has been assessed (March 2002) along a 2-D vertical section from Europe into the centre of the north Atlantic. Input from above of Fe(II) dissolved in rainwater from Sahara dust blown over the central Atlantic will be quantified at sea (October 2002), and related to observed plankton production. Different chemical forms of iron are being assessed and a certification excercise for Fe in seawater also under aegis of SCOR Working Group 109 is being completed (December 2002). For two major DMS-producing algal groups Phaeocystis sp. and Emiliania huxleyi the life cycle, Fe limitation, export production, CO2 uptake and DMS emissions have been synthesized from existing literature and laboratory experiments. This is being fed into ecosystem modeling, as well as into DMS(P) pathway modeling. Also know-how has been synthesized for three other major classes (diatoms, N2-fixing Trichodesmium and nano-pico-plankton) and fed into the ecosystem modeling. Pathways of DMS(P) in blooms are being simulated. An existing plankton ecosystem model already well predicts limitation by four nutrients (N, P, Si, Fe) of two algal groups (diatoms and nanoplankton) including export and CO2 air/sea exchange. This is being expanded with 3 other groups of algae and DMS(P)pathways. Next this extended ecosystem model is being simplified while maintaining reliable output for export and CO2/DMS gas exchange. This unit will then be put into two existing OBCM's. Inputs of Fe from above and below into the oceans have been modeled. Moreover a simple global Fe cycling model has been verified versus field data and insights. Two different OBCM's with same upper ocean ecosystem/DMS unit and Fe cycling will be verified versus pre-industrial and present conditions. Next climate change scenario's, notably changes in Fe inputs, will be run, with special attention to climatic feedbacks (warming) on the oceanic cycles and fluxes.

Debaar, H. J.

2002-12-01

306

ASUPT (Advanced Simulation in Undergraduate Pilot Training) Automated Objective Performance Measurement System.  

National Technical Information Service (NTIS)

To realize its full research potential a need exists for the development of an automated objective pilot performance evaluation system for use in the Advanced Simulation in Undergraduate Pilot Training (ASUPT) facility. The present report documents the ap...

W. L. Waag E. E. Eddowes J. H. Fuller R. R. Fuller

1975-01-01

307

Advanced numerical methods and software approaches for semiconductor device simulation  

SciTech Connect

In this article the authors concisely present several modern strategies that are applicable to drift-dominated carrier transport in higher-order deterministic models such as the drift-diffusion, hydrodynamic, and quantum hydrodynamic systems. The approaches include extensions of upwind and artificial dissipation schemes, generalization of the traditional Scharfetter-Gummel approach, Petrov-Galerkin and streamline-upwind Petrov Galerkin (SUPG), entropy variables, transformations, least-squares mixed methods and other stabilized Galerkin schemes such as Galerkin least squares and discontinuous Galerkin schemes. The treatment is representative rather than an exhaustive review and several schemes are mentioned only briefly with appropriate reference to the literature. Some of the methods have been applied to the semiconductor device problem while others are still in the early stages of development for this class of applications. They have included numerical examples from the recent research tests with some of the methods. A second aspect of the work deals with algorithms that employ unstructured grids in conjunction with adaptive refinement strategies. The full benefits of such approaches have not yet been developed in this application area and they emphasize the need for further work on analysis, data structures and software to support adaptivity. Finally, they briefly consider some aspects of software frameworks. These include dial-an-operator approaches such as that used in the industrial simulator PROPHET, and object-oriented software support such as those in the SANDIA National Laboratory framework SIERRA.

CAREY,GRAHAM F.; PARDHANANI,A.L.; BOVA,STEVEN W.

2000-03-23

308

Simulation of an advanced negative i-line photoresist  

NASA Astrophysics Data System (ADS)

A new i-line negative resist has been developed which exploits acid-catalyzed cross-linking chemistry in combination with a sensitizing chromophore and a light absorbing dye. During exposure acid is generated by excitation energy transfer from the sensitizer to a halogen- containing compound. Concurrently, the highly absorbing dye is bleached. The optical component of this resist can be modeled as follows: the imaginary part of the complex refractive index is proportional to A1M1 + A2M2 + B, where M1 is the bleachable dye concentration, M2 is the sensitizer concentration, B is the fixed absorption and A1 and A2 are the corresponding Dill coefficients for bleachable absorbance. The kinetics of the bleachable dye and sensitizer decays are given by (delta) Mi/(delta) t equals -CiMiI. The final acid concentration is a nonlinear function of these concentrations and can be expressed as H equals [(1-M2) + (kappa) (1-M1)]/(1 + (kappa) ) with (kappa) determined experimentally. The exposure is computed by our spectral element numerical method. As exposure terminates, post exposure baking (PEB) takes place, similar in form to the crosslinking of the deep-UV product MegapositR SNRTM 248 Series photoresist. This step is modeled via reaction diffusion equations, producing a nonsoluble monolith due to cross-linking of the polymers. The final profiles are obtained by solution of a system of reaction-diffusion equations and are described graphically using a novel dynamic triangulation algorithm. A comparison between simulated and actual micrographs is given and process latitude and CD control discussed.

Barouch, Eytan; Hollerbach, Uwe; Orszag, Steven A.; Allen, Mary T.; Calabrese, Gary S.

1991-07-01

309

User's manual for ADAM (Advanced Dynamic Airfoil Model)  

SciTech Connect

The computer code for an advanced dynamic airfoil model (ADAM) is described. The code is capable of calculating steady or unsteady flow over two-dimensional airfoils with allowances for boundary layer separation. Specific types of airfoil motions currently installed are steady rectilinear motion, impulsively started rectilinear motion, constant rate pitching, sinusoidal pitch oscillations, sinusoidal lateral plunging, and simulated Darrieus turbine motion. Other types of airfoil motion may be analyzed through simple modifications of a single subroutine. The code has a built-in capability to generate the geometric parameters for a cylinder, the NACA four-digit series of airfoils, and a NASA NLF-0416 laminar airfoil. Other types of airfoils are easily incorporated. The code ADAM is currently in a state of development. It is theoretically consistent and complete. However, further work is needed on the numerical implementation of the method.

Oler, J.W.; Strickland, J.H.; Im, B.J.

1987-06-01

310

Simulation of Thin-Film Damping and Thermal Mechanical Noise Spectra for Advanced Micromachined Microphone Structures.  

PubMed

In many micromachined sensors the thin (2-10 ?m thick) air film between a compliant diaphragm and backplate electrode plays a dominant role in shaping both the dynamic and thermal noise characteristics of the device. Silicon microphone structures used in grating-based optical-interference microphones have recently been introduced that employ backplates with minimal area to achieve low damping and low thermal noise levels. Finite-element based modeling procedures based on 2-D discretization of the governing Reynolds equation are ideally suited for studying thin-film dynamics in such structures which utilize relatively complex backplate geometries. In this paper, the dynamic properties of both the diaphragm and thin air film are studied using a modal projection procedure in a commonly used finite element software and the results are used to simulate the dynamic frequency response of the coupled structure to internally generated electrostatic actuation pressure. The model is also extended to simulate thermal mechanical noise spectra of these advanced sensing structures. In all cases simulations are compared with measured data and show excellent agreement-demonstrating 0.8 pN/?Hz and 1.8 ?Pa/?Hz thermal force and thermal pressure noise levels, respectively, for the 1.5 mm diameter structures under study which have a fundamental diaphragm resonance-limited bandwidth near 20 kHz. PMID:19081811

Hall, Neal A; Okandan, Murat; Littrell, Robert; Bicen, Baris; Degertekin, F Levent

2008-06-01

311

Simulation of Thin-Film Damping and Thermal Mechanical Noise Spectra for Advanced Micromachined Microphone Structures  

PubMed Central

In many micromachined sensors the thin (2–10 ?m thick) air film between a compliant diaphragm and backplate electrode plays a dominant role in shaping both the dynamic and thermal noise characteristics of the device. Silicon microphone structures used in grating-based optical-interference microphones have recently been introduced that employ backplates with minimal area to achieve low damping and low thermal noise levels. Finite-element based modeling procedures based on 2-D discretization of the governing Reynolds equation are ideally suited for studying thin-film dynamics in such structures which utilize relatively complex backplate geometries. In this paper, the dynamic properties of both the diaphragm and thin air film are studied using a modal projection procedure in a commonly used finite element software and the results are used to simulate the dynamic frequency response of the coupled structure to internally generated electrostatic actuation pressure. The model is also extended to simulate thermal mechanical noise spectra of these advanced sensing structures. In all cases simulations are compared with measured data and show excellent agreement—demonstrating 0.8 pN/?Hz and 1.8 ?Pa/?Hz thermal force and thermal pressure noise levels, respectively, for the 1.5 mm diameter structures under study which have a fundamental diaphragm resonance-limited bandwidth near 20 kHz.

Hall, Neal A.; Okandan, Murat; Littrell, Robert; Bicen, Baris; Degertekin, F. Levent

2008-01-01

312

ATC-lab Advanced : An air traffic control simulator with realism and control  

Microsoft Academic Search

ATC-labAdvanced is a new, publicly available air traffic control (ATC) simulation package that provides both realism and experimental control.\\u000a ATC-labAdvanced simulations are realistic to the extent that the display features (including aircraft performance) and the manner in which\\u000a participants interact with the system are similar to those used in an operational environment. Experimental control allows\\u000a researchers to standardize air traffic

Selina Fothergill; Shayne Loft; Andrew Neal

2009-01-01

313

Modeling and simulation of friction  

Microsoft Academic Search

Two new models for 'slip-stick' friction are presented. One, called the 'bristle model,' is an approximation designed to capture the physical phenomenon of sticking. This model is relatively inefficient numerically. The other model, called the 'reset integrator model,' does not capture the details for the sticking phenomenon, but is numerically efficient and exhibits behavior similar to the model proposed by

David A. Haessig; Bernard Friedland

1991-01-01

314

Advanced Governor Controller for Pumped-Storage Power Plant and Its Simulation Tool  

Microsoft Academic Search

This paper presents new governor control strategy for hydroelectric power plant and plant simulation technique for functional tests of new governor equipment, which have been applied to advanced governor in Kannagawa pumped-storage power plant. The main feature of the advanced governor controller is an ability of reducing water level variation in surge chamber when a sudden flow rate change occurs

K. Iwabuchi; Y. Takagi; T. Konnai; Y. Nakahara; K. Kubota; M. Ubukata; K. Masaki

2006-01-01

315

Advanced simulation of electron heat transport in fusion plasmas  

Microsoft Academic Search

Electron transport in burning plasmas is more important since fusion products first heat electrons. First-principles simulations of electron turbulence are much more challenging due to the multi-scale dynamics of the electron turbulence, and have been made possible by close collaborations between plasma physicists and computational scientists. The GTC simulations of collisionless trapped electron mode (CTEM) turbulence show that the electron

Zhihong Lin; Y. Xiao; I. Holod; W. Zhang; Wenjun Deng; Scott A Klasky; J. Lofstead; Chandrika Kamath; Nathan Wichmann

2009-01-01

316

InsightArthroVR®, Advanced Arthroscopic Training Simulator  

Microsoft Academic Search

Minimal Invasive Surgery (MIS) techniques are becoming more and more frequent. However these techniques are complex and expensive procedures difficult to master. Current learning methods have a number of limita- tions that can be compensated for and complemented by our virtual reality simulator. Training with simulators considerably improves surgeons' dexterities with the arthroscopic instruments, redu- ces surgery times, increases surgery

Fernández Fernández-Arroyo JM; Potti Cuervo J; Illana Alejandro C; Pastor Pérez L; Rodríguez Martínez de Bartolomé; Bayona Beriso S

317

Physically-based Modeling and Simulation of Extraocular Muscles  

PubMed Central

Dynamic simulation of human eye movements, with realistic physical models of extraocular muscles (EOMs), may greatly advance our understanding of the complexities of the oculomotor system and aid in treatment of visuomotor disorders. In this paper we describe the first three dimensional (3D) biomechanical model which can simulate the dynamics of ocular motility at interactive rates. We represent EOMs using “strands”, which are physical primitives that can model an EOM's complex nonlinear anatomical and physiological properties. Contact between the EOMs, the globe, and orbital structures can be explicitly modeled. Several studies were performed to assess the validity and utility of the model. EOM deformation during smooth pursuit was simulated and compared with published experimental data; the model reproduces qualitative features of the observed non-uniformity. The model is able to reproduce realistic saccadic trajectories when the lateral rectus muscle was driven by published measurements of abducens neuron discharge. Finally, acute superior oblique palsy, a pathological condition, was simulated to further evaluate the system behavior; the predicted deviation patterns agree qualitatively with experimental observations. This example also demonstrates potential clinical applications of such a model.

Wei, Qi; Sueda, Shinjiro; Pai, Dinesh K.

2010-01-01

318

Protein Simulation Data in the Relational Model  

PubMed Central

High performance computing is leading to unprecedented volumes of data. Relational databases offer a robust and scalable model for storing and analyzing scientific data. However, these features do not come without a cost—significant design effort is required to build a functional and efficient repository. Modeling protein simulation data in a relational database presents several challenges: the data captured from individual simulations are large, multi-dimensional, and must integrate with both simulation software and external data sites. Here we present the dimensional design and relational implementation of a comprehensive data warehouse for storing and analyzing molecular dynamics simulations using SQL Server.

Simms, Andrew M.; Daggett, Valerie

2011-01-01

319

Recent advances in large-eddy simulation of spray and coal combustion  

NASA Astrophysics Data System (ADS)

Large-eddy simulation (LES) is under its rapid development and is recognized as a possible second generation of CFD methods used in engineering. Spray and coal combustion is widely used in power, transportation, chemical and metallurgical, iron and steel making, aeronautical and astronautical engineering, hence LES of spray and coal two-phase combustion is particularly important for engineering application. LES of two-phase combustion attracts more and more attention; since it can give the detailed instantaneous flow and flame structures and more exact statistical results than those given by the Reynolds averaged modeling (RANS modeling). One of the key problems in LES is to develop sub-grid scale (SGS) models, including SGS stress models and combustion models. Different investigators proposed or adopted various SGS models. In this paper the present author attempts to review the advances in studies on LES of spray and coal combustion, including the studies done by the present author and his colleagues. Different SGS models adopted by different investigators are described, some of their main results are summarized, and finally some research needs are discussed.

Zhou, L. X.

2013-07-01

320

Oil Market Simulation Model Documentation Report (OMS Model).  

National Technical Information Service (NTIS)

This report provides documentation of the Oil Market Simulation (OMS) Model, the principal model used by the Energy Information Administration (EIA) to project future world oil prices. The OMS model is continually being updated and improved. The methodolo...

M. Grillot

1983-01-01

321

Simulation model for aircraft line maintenance planning  

Microsoft Academic Search

This paper reports results of research that developed a computerized simulation model for the aircraft line maintenance department in Continental Airlines. The original AUTOMOD model that was created duplicated the maintenance operations at Continental's major maintenance station at Newark. Modeling the day-to-day maintenance activities lead to the development of enhanced staffing models and a better understanding of resource requirements on

P. Gupta; M. Bazargan; R. N. McGrath

2003-01-01

322

Automatic revision of simulation models  

Microsoft Academic Search

We have developed 007, an intelligent modeling assistant that assists a human modeler in three main revision tasks: (i) representation of the physical models, (ii) clarification of goals and formulation of explicit requirements, and (iii) modification of the physical model. 007 helps users to formulate explicit, testable requirements and to assess the current model. It then executes generic repair plans

A. Pos; H. Akkermans; J. Top

1998-01-01

323

Advanced tokamak research with integrated modeling in JT-60 Upgrade  

NASA Astrophysics Data System (ADS)

Researches on advanced tokamak (AT) have progressed with integrated modeling in JT-60 Upgrade [N. Oyama et al., Nucl. Fusion 49, 104007 (2009)]. Based on JT-60U experimental analyses and first principle simulations, new models were developed and integrated into core, rotation, edge/pedestal, and scrape-off-layer (SOL)/divertor codes. The integrated models clarified complex and autonomous features in AT. An integrated core model was implemented to take account of an anomalous radial transport of alpha particles caused by Alfven eigenmodes. It showed the reduction in the fusion gain by the anomalous radial transport and further escape of alpha particles. Integrated rotation model showed mechanisms of rotation driven by the magnetic-field-ripple loss of fast ions and the charge separation due to fast-ion drift. An inward pinch model of high-Z impurity due to the atomic process was developed and indicated that the pinch velocity increases with the toroidal rotation. Integrated edge/pedestal model clarified causes of collisionality dependence of energy loss due to the edge localized mode and the enhancement of energy loss by steepening a core pressure gradient just inside the pedestal top. An ideal magnetohydrodynamics stability code was developed to take account of toroidal rotation and clarified a destabilizing effect of rotation on the pedestal. Integrated SOL/divertor model clarified a mechanism of X-point multifaceted asymmetric radiation from edge. A model of the SOL flow driven by core particle orbits which partially enter the SOL was developed by introducing the ion-orbit-induced flow to fluid equations.

Hayashi, N.; JT-60 Team

2010-05-01

324

Advanced tokamak research with integrated modeling in JT-60 Upgrade  

SciTech Connect

Researches on advanced tokamak (AT) have progressed with integrated modeling in JT-60 Upgrade [N. Oyama et al., Nucl. Fusion 49, 104007 (2009)]. Based on JT-60U experimental analyses and first principle simulations, new models were developed and integrated into core, rotation, edge/pedestal, and scrape-off-layer (SOL)/divertor codes. The integrated models clarified complex and autonomous features in AT. An integrated core model was implemented to take account of an anomalous radial transport of alpha particles caused by Alfven eigenmodes. It showed the reduction in the fusion gain by the anomalous radial transport and further escape of alpha particles. Integrated rotation model showed mechanisms of rotation driven by the magnetic-field-ripple loss of fast ions and the charge separation due to fast-ion drift. An inward pinch model of high-Z impurity due to the atomic process was developed and indicated that the pinch velocity increases with the toroidal rotation. Integrated edge/pedestal model clarified causes of collisionality dependence of energy loss due to the edge localized mode and the enhancement of energy loss by steepening a core pressure gradient just inside the pedestal top. An ideal magnetohydrodynamics stability code was developed to take account of toroidal rotation and clarified a destabilizing effect of rotation on the pedestal. Integrated SOL/divertor model clarified a mechanism of X-point multifaceted asymmetric radiation from edge. A model of the SOL flow driven by core particle orbits which partially enter the SOL was developed by introducing the ion-orbit-induced flow to fluid equations.

Hayashi, N. [Fusion Research and Development Directorate, Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan)

2010-05-15

325

Microdata Simulation Modeling After Twenty Years  

Microsoft Academic Search

This article describes and assesses the development of a major evaluation and policy research tool-microdata simulation modeling-over the past two decades. The method of microdata simulation modeling is described and its reliance on the development of large, nationally weighted household surveys is noted. After a brief tracing of the history of this evaluation method from the first-generation static models to

Robert H. Haveman

1986-01-01

326

Stress trajectory and advanced hydraulic-fracture simulations for the Eastern Gas Shales Project. Final report, April 30, 1981-July 30, 1983  

SciTech Connect

A summary review of hydraulic fracture modeling is given. Advanced hydraulic fracture model formulations and simulation, using the finite element method, are presented. The numerical examples include the determination of fracture width, height, length, and stress intensity factors with the effects of frac fluid properties, layered strata, in situ stresses, and joints. Future model extensions are also recommended. 66 references, 23 figures.

Advani, S.H.; Lee, J.K.

1983-01-01

327

Advanced Wellbore Thermal Simulator GEOTEMP2 User Manual.  

National Technical Information Service (NTIS)

GEOTEMP2 is a wellbore thermal simulator computer code designed for geothermal drilling and production applications. The code treats natural and forced convection and conduction within the wellbore and heat conduction within the surrounding rock matrix. A...

L. A. Mondy L. E. Duda

1984-01-01

328

Advances in a European Planetary Simulation Wind Tunnel Facility  

NASA Astrophysics Data System (ADS)

The Mars Simulation wind tunnel at Aarhus University is a unique ESA and EU supported simulation facility designed for studies of the Martian environment. Specifically it is capable of recreating the key physical parameters such as temperature, pressure (composition), wind flow and importantly the suspension of dust particulates. This facility is available to the scientific community for collaborative research. Preliminary results from the first year of facility operations will be presented.

Merrison, J.; Aye, K. M.; Holstein-Rathlou, C.; Mason, J.; Merlone, A.; Nørnberg, P.; Patel, M.; Portyankina, G.; Rasmussen, K. R.

2012-09-01

329

Neural network setpoint control of an advanced test reactor experiment loop simulation  

Microsoft Academic Search

This report describes the design, implementation, and application of artificial neural networks to achieve temperature and flow rate control for a simulation of a typical experiment loop in the Advanced Test Reactor (ATR) located at the Idaho National Engineering Laboratory (INEL). The goal of the project was to research multivariate, nonlinear control using neural networks. A loop simulation code was

G. A. Cordes; S. R. Bryan; R. H. Powell; D. R. Chick

1990-01-01

330

Large blast and thermal simulator advanced concept driver design by computational fluid dynamics  

Microsoft Academic Search

The construction of a large test facility is proposed for simulating the blast and thermal environment resulting from nuclear explosions. This facility would be used to test the survivability and vulnerability of military equipment such as trucks, tanks and helicopters in a simulated thermal and blast environment, and to perform research into nuclear blast phenomenology. The proposed advanced design concepts,

Klaus O. Opalka

1989-01-01

331

Simulation of large-scale rule-based models  

SciTech Connect

Interactions of molecules, such as signaling proteins, with multiple binding sites and/or multiple sites of post-translational covalent modification can be modeled using reaction rules. Rules comprehensively, but implicitly, define the individual chemical species and reactions that molecular interactions can potentially generate. Although rules can be automatically processed to define a biochemical reaction network, the network implied by a set of rules is often too large to generate completely or to simulate using conventional procedures. To address this problem, we present DYNSTOC, a general-purpose tool for simulating rule-based models. DYNSTOC implements a null-event algorithm for simulating chemical reactions in a homogenous reaction compartment. The simulation method does not require that a reaction network be specified explicitly in advance, but rather takes advantage of the availability of the reaction rules in a rule-based specification of a network to determine if a randomly selected set of molecular components participates in a reaction during a time step. DYNSTOC reads reaction rules written in the BioNetGen language which is useful for modeling protein-protein interactions involved in signal transduction. The method of DYNSTOC is closely related to that of STOCHSIM. DYNSTOC differs from STOCHSIM by allowing for model specification in terms of BNGL, which extends the range of protein complexes that can be considered in a model. DYNSTOC enables the simulation of rule-based models that cannot be simulated by conventional methods. We demonstrate the ability of DYNSTOC to simulate models accounting for multisite phosphorylation and multivalent binding processes that are characterized by large numbers of reactions. DYNSTOC is free for non-commercial use. The C source code, supporting documentation and example input files are available at .

Hlavacek, William S [Los Alamos National Laboratory; Monnie, Michael I [Los Alamos National Laboratory; Colvin, Joshua [NON LANL; Faseder, James [NON LANL

2008-01-01

332

Simulation model for the closed plant experiment facility of CEEF  

NASA Astrophysics Data System (ADS)

The Closed Ecology Experiment Facilities (CEEF) is a testbed for Controlled Ecological Life Support Systems (CELSS) investigations. CEEF including the physico-chemical material regenerative system has been constructed for the experiments of material circulation among plants, breeding animals and crew of CEEF. Because CEEF is a complex system, an appropriate schedule for the operation must be prepared in advance. The CEEF behavioral Prediction System, CPS, that will help to confirm the operation schedule, is under development. CPS will simulate CEEFs behavior with data (conditions of equipments, quantity of materials in tanks, etc.) of CEEF and an operation schedule that will be made by the operation team everyday, before the schedule will be carried out. The result of the simulation will show whether the operation schedule is appropriate or not. In order to realize CPS, models of the simulation program that is installed in CPS must mirror the real facilities of CEEF. For the first step of development, a flexible algorithm of the simulation program was investigated. The next step was development of a replicate simulation model of the material circulation system for the Closed Plant Experiment Facility (CPEF) that is a part of CEEF. All the parts of a real material circulation system for CPEF are connected together and work as a complex mechanism. In the simulation model, the system was separated into 38 units according to its operational segmentation. In order to develop each model for its corresponding unit, specifications for the model were fixed based on the specifications of the real part. These models were put into a simulation model for the system.

Abe, Koichi; Ishikawa, Yoshio; Kibe, Seishiro; Nitta, Keiji

333

Advanced numerical simulation of fluidized catalytic cracking riser reactors  

Microsoft Academic Search

Fluidized Catalytic Cracking (FCC) is the primary conversion process in modern oil refining. It uses a catalyst to convert heavy oil into lighter oil products in a riser. In order to meet increasing demands and succeed in a competitive market, it is desired to improve performance of current FCC units and to design new, advanced units. To achieve these goals,

Bonnie Bowman

2004-01-01

334

Knowledge-enhanced network simulation modeling of the nuclear power plant operator  

Microsoft Academic Search

Simulation models of the human operator of advanced control systems must provide an adequate account of the cognitive processes required to control these systems. The Integrated Reactor Operator\\/System (INTEROPS) prototype model was developed at Oak Ridge National Laboratory (ORNL) to demonstrate the feasibility of dynamically integrating a cognitive operator model and a continuous plant process model (ARIES-P) to provide predictions

J. C. Schryver; L. E. Palko

1988-01-01

335

Design tradeoffs in the development of the advanced multispectral simulation test acceptance resource (AMSTAR) HWIL facilities  

NASA Astrophysics Data System (ADS)

The Army's Advanced Multispectral Simulation Test Acceptance Resource (AMSTAR) is a suite of missile Hardware-In-the-Loop (HWIL) simulation / test capabilities designed to support testing from concept through production. This paper presents the design tradeoffs that were conducted in the development of the AMSTAR sensor stimulators and the flight motion simulators. The AMSTAR facility design includes systems to stimulate each of the Millimeter Wave (MMW), Infrared (IR), and Semi-Active Laser (SAL) sensors. The flight motion simulator (FMS) performance was key to the success of the simulation but required many concessions to accommodate the design considerations for the tri-mode stimulation systems.

LeSueur, Kenneth G.; Almendinger, Frank J.

2007-04-01

336

Calibration and validation of CERES model for simulating  

Microsoft Academic Search

Crop simulation models (CSM) were built to simulate the crop response to environment and soil on plot levels and were gradually applied for simulating regional behaviours of crop. Most of the models applied for simulating regional behaviour are general crop sim- ulation models or crop-specific simulation models. The models, which use cultivar specific information, are difficult to apply on regional

Ajeet Singh Nain; Kurt Christian Kersebaum

337

Cost-efficiency assessment of Advanced Life Support (ALS) courses based on the comparison of advanced simulators with conventional manikins  

PubMed Central

Background Simulation is an essential tool in modern medical education. The object of this study was to assess, in cost-effective measures, the introduction of new generation simulators in an adult life support (ALS) education program. Methods Two hundred fifty primary care physicians and nurses were admitted to ten ALS courses (25 students per course). Students were distributed at random in two groups (125 each). Group A candidates were trained and tested with standard ALS manikins and Group B ones with new generation emergency and life support integrated simulator systems. Results In group A, 98 (78%) candidates passed the course, compared with 110 (88%) in group B (p < 0.01). The total cost of conventional courses was €7689 per course and the cost of the advanced simulator courses was €29034 per course (p < 0.001). Cost per passed student was €392 in group A and €1320 in group B (p < 0.001). Conclusion Although ALS advanced simulator systems may slightly increase the rate of students who pass the course, the cost-effectiveness of ALS courses with standard manikins is clearly superior.

Iglesias-Vazquez, Jose Antonio; Rodriguez-Nunez, Antonio; Penas-Penas, Monica; Sanchez-Santos, Luis; Cegarra-Garcia, Maria; Barreiro-Diaz, Maria Victoria

2007-01-01

338

CONTAMINANT TRANSPORT MODELS FOR GROUNDWATER QUALITY SIMULATION  

Microsoft Academic Search

Groundwater solute transport models are now capable of simulating the migration of contaminants in complex real-world systems when sufficient data are available. A variety of numerical methods have been applied successfully to solving the transport equation, and no single method is best for all problems. Over the past 10 to 15 years techniques have been developed to simulate chemical reactions

STEVEN M. GORELICK

339

Modeling and simulating electronic textile applications  

Microsoft Academic Search

This paper describes our design of a simulation environment for electronic textiles (e-textiles) and our experiences with that environment. This simulation environment, based upon Ptolemy II, enables us to model a diverse range of areas related to the design of electronic textiles, including the physical environment they will be used in, the behavior of the sensors incorporated into the fabric,

Thomas Martin; Mark Jones; Joshua Edmison; Tanwir Sheikh; Zahi Nakad

2004-01-01

340

Consequence modeling using the fire dynamics simulator  

Microsoft Academic Search

The use of Computational Fluid Dynamics (CFD) and in particular Large Eddy Simulation (LES) codes to model fires provides an efficient tool for the prediction of large-scale effects that include plume characteristics, combustion product dispersion, and heat effects to adjacent objects. This paper illustrates the strengths of the Fire Dynamics Simulator (FDS), an LES code developed by the National Institute

Noah L. Ryder; Jason A. Sutula; Christopher F. Schemel; Andrew J. Hamer; Vincent Van Brunt

2004-01-01

341

Hydrologic Simulation With a Distributed Hydrologic Model  

Microsoft Academic Search

Hydrologic processes are sensitive to the spatial distribution of hydrologic parameters in watersheds. A distributed hydrologic model which can simulate various components of a watershed hydrologic cycle such as surface water, channel water, soil water and groundwater as well their interactions is used to simulate various hydrologic processes in the Meilin watershed in this paper. The parameters with physical meanings

Xing Chen; Zhongbo Yu; Guangbai Cui

2008-01-01

342

A mass spring model for hair simulation  

Microsoft Academic Search

Our goal is to simulate the full hair geometry, consisting of approximately one hundred thousand hairs on a typical human head. This will require scalable methods that can simulate every hair as opposed to only a few guide hairs. Novel to this approach is that the individual hair\\/hair interactions can be modeled with physical parameters (friction, static attraction, etc.) at

Andrew Selle; Michael Lentine; Ronald Fedkiw

2008-01-01

343

A mass spring model for hair simulation  

Microsoft Academic Search

Our goal is to simulate the full hair geometry, consisting of ap- proximately one hundred thousand hairs on a typical human head. This will require scalable methods that can simulate every hair as opposed to only a few guide hairs. Novel to this approach is that the individual hair\\/hair interactions can be modeled with physical parameters (friction, static attraction, etc.)

Andrew Selle; Michael Lentine; Ronald Fedkiw

2008-01-01

344

Modeling Physics with Easy Java Simulations  

NSDL National Science Digital Library

The paper Modeling Physics with Easy Java Simulations describes the use of the Easy Java Simulations (Ejs) modeling and authoring tool and shows how this tool can be used to teach mechanics concepts using computer modeling. Although the modeling method can be used without computers, the use of computers allows students to study problems that are difficult and time consuming, to visualize their results, and to communicate their results with others. The combination of computer modeling with theory and experiment can achieve insight and understanding that cannot be achieved with only one approach. Journal article available from http://scitation.aip.org/tpt/

Christian, Wolfgang; Franciscouembre

2008-05-30

345

SIMULATION MODELING OF GASTROINTESTINAL ABSORPTION  

EPA Science Inventory

Mathematical dosimetry models incorporate mechanistic determinants of chemical disposition in a living organism to describe relationships between exposure concentration and the internal dose needed for PBPK models and human health risk assessment. Because they rely on determini...

346

Seismic Simulations Using Parallel Computing and Three-Dimensional Earth Models to Improve Nuclear Explosion Phenomenology and Monitoring.  

National Technical Information Service (NTIS)

The development of accurate numerical methods to simulate wave propagation in three-dimensional (3D) earth models and advances in computational power offer exciting possibilities for modeling the motions excited by underground nuclear explosions. This pre...

A. Petersson A. J. Rodgers B. A. Sjogreen E. Matzel M. E. Pasyanos

2008-01-01

347

Design and simulation of advanced fault tolerant flight control schemes  

NASA Astrophysics Data System (ADS)

This research effort describes the design and simulation of a distributed Neural Network (NN) based fault tolerant flight control scheme and the interface of the scheme within a simulation/visualization environment. The goal of the fault tolerant flight control scheme is to recover an aircraft from failures to its sensors or actuators. A commercially available simulation package, Aviator Visual Design Simulator (AVDS), was used for the purpose of simulation and visualization of the aircraft dynamics and the performance of the control schemes. For the purpose of the sensor failure detection, identification and accommodation (SFDIA) task, it is assumed that the pitch, roll and yaw rate gyros onboard are without physical redundancy. The task is accomplished through the use of a Main Neural Network (MNN) and a set of three De-Centralized Neural Networks (DNNs), providing analytical redundancy for the pitch, roll and yaw gyros. The purpose of the MNN is to detect a sensor failure while the purpose of the DNNs is to identify the failed sensor and then to provide failure accommodation. The actuator failure detection, identification and accommodation (AFDIA) scheme also features the MNN, for detection of actuator failures, along with three Neural Network Controllers (NNCs) for providing the compensating control surface deflections to neutralize the failure induced pitching, rolling and yawing moments. All NNs continue to train on-line, in addition to an offline trained baseline network structure, using the Extended Back-Propagation Algorithm (EBPA), with the flight data provided by the AVDS simulation package. The above mentioned adaptive flight control schemes have been traditionally implemented sequentially on a single computer. This research addresses the implementation of these fault tolerant flight control schemes on parallel and distributed computer architectures, using Berkeley Software Distribution (BSD) sockets and Message Passing Interface (MPI) for inter-process communication.

Gururajan, Srikanth

348

NUMERICAL SIMULATION OF ADVANCED ADSORPTION REFRIGERATION CHILLER WITH MASS RECOVERY  

Microsoft Academic Search

This paper investigates the thermodynamic framework of a three-bed advanced adsorption chiller, where the mass recovery scheme has been utilized such that the performances of this chiller could be improved and a CFC-free-based sorption chiller driven by the low-grade waste heat or any renewable energy source can be developed for the next generation of refrigeration. Silica gel-water is chosen as

M. Z. I. Khan; S. Sultana; A. Akisawa; T. Kashiwagi

2006-01-01

349

Modeling and Simulating Chemical Reactions  

Microsoft Academic Search

Abstract Many students are familiar with the idea of modeling chemical reactions in terms of ordinary dieren tial equations. However, these deterministic reaction rate equations are really a certain large-scale limit of a sequence of ner-scale probabilistic models. In studying this hierarchy of models, students can be exposed to a range of modern ideas in applied and compu- tational mathematics.

Desmond J. Higham

2008-01-01

350

Maintenance Personnel Performance Simulation (MAPPS) model  

SciTech Connect

A stochastic computer model for simulating the actions and behavior of nuclear power plant maintenance personnel is described. The model considers personnel, environmental, and motivational variables to yield predictions of maintenance performance quality and time to perform. The mode has been fully developed and sensitivity tested. Additional evaluation of the model is now taking place.

Siegel, A.I.; Bartter, W.D.; Wolf, J.J.; Knee, H.E.; Haas, P.M.

1984-01-01

351

Computing Intensive Simulations in Biofilm Modeling  

Microsoft Academic Search

We present a brief overview of past and future applications of high performance computing in biofilm modeling. In particular we show that even relative simple two-dimensional models lead to computing expensive simulation experiments, due to data uncertainties inherent in all biofilm models.

Hermann J. Eberl; Nasim Muhammad; Rangarajan Sudarsan

2008-01-01

352

Simulation of Drying Using a Kiln Model  

Microsoft Academic Search

A mathematical model was developed for simulating a convective batch lumber drying process. The model incorporates mass and heat transfer relationships within the lumber stack, as well as thermodynamic properties of the wood and drying air. It takes into account the change of air properties along the stack and its effect on the mass and heat transfer parameters. The model

Adin H. Berberovi?; Michael R. Milota

2008-01-01

353

Electricity Portfolio Simulation Model (EPSim) Technical Description.  

National Technical Information Service (NTIS)

Stakeholders often have competing interests when selecting or planning new power plants. The purpose of developing this preliminary Electricity Portfolio Simulation Model (EPSim) is to provide a first cut, dynamic methodology and approach to this problem,...

T. E. Drennen R. Klotz

2005-01-01

354

A Simulation To Model Exponential Growth.  

ERIC Educational Resources Information Center

|Describes a simulation using dice-tossing students in a population cluster to model the growth of cancer cells. This growth is recorded in a scatterplot and compared to an exponential function graph. (KHR)|

Appelbaum, Elizabeth Berman

2000-01-01

355

Mathematical Modeling of Simulated Photochemical Smog.  

National Technical Information Service (NTIS)

This report deals with the continuing effort to develop a chemical kinetic mechanism to describe the formation of photochemical smog. Using the technique of computer modeling to simulate smog chamber data, several explicit kinetic mechanisms for specific ...

G. Z. Whitten H. Hogo

1977-01-01

356

Modeling and simulation of dielectric elastomer actuators  

NASA Astrophysics Data System (ADS)

Dielectric elastomers are used as base material for so-called electroactive polymer (EAP) actuators. A procedure and a specific constitutive model (for the acrylic elastomer VHB 4910) are presented in this work for finite element modeling and simulation of dielectric elastomer actuators of general shape and set-up. The Yeoh strain energy potential and the Prony series are used for describing the large strain time-dependent mechanical response of the dielectric elastomer. Material parameters were determined from uniaxial experiments (relaxation tests and tensile tests). Thereby the inverse problem was solved using iterative finite element calculations. A pre-strained circular actuator was built and activated with a predefined voltage. A three-dimensional finite element model of the circular actuator was created and the electromechanical activation process simulated. Simulation and actual measurements agree to a great extent, thus leading to a validation of both the constitutive model and the actuator simulation procedure proposed in this work.

Wissler, Michael; Mazza, Edoardo

2005-12-01

357

Modelling and simulation of thermal power plants.  

National Technical Information Service (NTIS)

Mathematical modelling and simulation are important tools when dealing with engineering systems that today are becoming increasingly more complex. Integrated production and recycling of materials are trends that give rise to heterogenous systems, which ar...

J. Eborn

1998-01-01

358

MODELING CONCEPTS FOR BMP/LID SIMULATION  

EPA Science Inventory

Enhancement of simulation options for stormwater best management practices (BMPs) and hydrologic source control is discussed in the context of the EPA Storm Water Management Model (SWMM). Options for improvement of various BMP representations are presented, with emphasis on inco...

359

Structural model uncertainty in stochastic simulation  

SciTech Connect

Prediction uncertainty in stochastic simulation models can be described by a hierarchy of components: stochastic variability at the lowest level, input and parameter uncertainty at a higher level, and structural model uncertainty at the top. It is argued that a usual paradigm for analysis of input uncertainty is not suitable for application to structural model uncertainty. An approach more likely to produce an acceptable methodology for analyzing structural model uncertainty is one that uses characteristics specific to the particular family of models.

McKay, M.D.; Morrison, J.D. [Los Alamos National Lab., NM (United States). Technology and Safety Assessment Div.

1997-09-01

360

Simulation and Formal Analysis of Workow Models  

Microsoft Academic Search

Abstract We present a framework for the simulation and formal analysis of workow,models. We discuss (i) how a workow,model, implemented in the BPEL language, can be transformed into a dataow,network model, (ii) how potentially incorrect execution paths can be incorporated, and (iii) how the properties of a workow can be formally veried,using the SPIN model checker. For the several model

Mate Kovacs; Laszlo Gonczy

361

Verification validation and accreditation of simulation models  

Microsoft Academic Search

This paper presents guidelines for conducting verifica- tion, validation and accreditation (VV&A) of simulation models. Fifteen guiding principles are introduced to help the researchers, practitioners and managers better com- prehend what VV&A is all about. The VV&A activities are described in the modeling and simulation life cycle. A taxonomy of more than 77 V&V techniques is provided to assist simulationists

Osman Balci

1997-01-01

362

Simulated classical tests in multinomial probit models  

Microsoft Academic Search

This paper compares the application of different versions of the simulated counterparts of the Wald test, the score test,\\u000a and the likelihood ratio test in one- and multiperiod multinomial probit models. Monte Carlo experiments show that the use\\u000a of the simple form of the simulated likelihood ratio test delivers relatively robust results regarding the testing of several\\u000a multinomial probit model

Andreas Ziegler

2007-01-01

363

Hardware Performance Simulations of Round 2 Advanced Encryption Standard Algorithms  

Microsoft Academic Search

The National Security Agency (NSA) is providing hardware simulation support and performance measurements toaid NIST in their selection of the AES algorithm. Although much of the Round 1 analysis focused on software,much more attention will be directed towards hardware implementation issues in the Round 2 analysis. As NIST hasstated, a common set of assumptions will be essential in comparing the

Mark Bean; Tom Rozylowicz; Chris Ficke

2000-01-01

364

Human response simulation and quantification the advanced biodynamic manikin  

Microsoft Academic Search

The research use of manikins for human simulation and dynamic testing within the automotive and aircraft environments has been well documented by the military and automotive research communities. The evaluation of escape systems, crashworthy seating systems, life support devices, restraint systems, and airbag systems are all subject to testing utilizing biodynamic manikins. The manikin functions to load the aircraft or

P. H. Frisch

1994-01-01

365

ADVANCES IN COMPREHENSIVE GYROKINETIC SIMULATIONS OF TRANSPORT IN TOKAMAKS  

Microsoft Academic Search

A continuum global gyrokinetic code GYRO has been developed to comprehensively simulate core turbulent transport in actual experimental profiles and enable direct quantitative comparisons to the experimental transport flows. GYRO not only treats the now standard ion temperature gradient (ITG) mode turbulence, but also treats trapped and passing electrons with collisions and finite β, equilibrium ExB shear stabilization, and all

WALTZ RE; CANDY J; HINTON FL; ESTRADA-MILA C; KINSEY JE

2004-01-01

366

Advances in comprehensive gyrokinetic simulations of transport in tokamaks  

Microsoft Academic Search

A continuum global gyrokinetic code GYRO has been developed to comprehensively simulate core turbulent transport in actual experimental profiles and enable direct quantitative comparisons to the experimental transport flows. GYRO treats not only the now standard ion temperature gradient (ITG) mode turbulence but also trapped and passing electrons with collisions and finite beta, equilibrium E × B shear stabilization and

R. E. Waltz; J. Candy; F. L. Hinton; C. Estrada-Mila; J. E. Kinsey

2005-01-01

367

Advances in comprehensive gyrokinetic simulations of transport in tokamaks  

Microsoft Academic Search

A continuum global gyrokinetic code GYRO has been developed to comprehensively simulate core turbulent transport in actual experimental profiles and enable direct quantitative comparisons to the experimental transport flows. GYRO treats not only the now standard ion temperature gradient (ITG) mode turbulence but also trapped and passing electrons with collisions and finite ?, equilibrium E × B shear stabilization and

R. E. Waltz; J. Candy; F. L. Hinton; C. Estrada-Mila; J. E. Kinsey

2005-01-01

368

Using Simulations to Model Shared Mental Models.  

National Technical Information Service (NTIS)

Good team members seem to have the ability to simulate what others on the team will do in different situations. Team researchers have long studied what makes an effective team. Their methodology has been to examine how high and low performing teams accomp...

J. G. Trafton W. G. Kennedy

2007-01-01

369

Lattice Boltzmann modeling of directional wetting: comparing simulations to experiments.  

PubMed

Lattice Boltzmann Modeling (LBM) simulations were performed on the dynamic behavior of liquid droplets on chemically striped patterned surfaces, ultimately with the aim to develop a predictive tool enabling reliable design of future experiments. The simulations accurately mimic experimental results, which have shown that water droplets on such surfaces adopt an elongated shape due to anisotropic preferential spreading. Details of the contact line motion such as advancing of the contact line in the direction perpendicular to the stripes exhibit pronounced similarities in experiments and simulations. The opposite of spreading, i.e., evaporation of water droplets, leads to a characteristic receding motion first in the direction parallel to the stripes, while the contact line remains pinned perpendicular to the stripes. Only when the aspect ratio is close to unity, the contact line also starts to recede in the perpendicular direction. Very similar behavior was observed in the LBM simulations. Finally, droplet movement can be induced by a gradient in surface wettability. LBM simulations show good semiquantitative agreement with experimental results of decanol droplets on a well-defined striped gradient, which move from high- to low-contact angle surfaces. Similarities and differences for all systems are described and discussed in terms of the predictive capabilities of LBM simulations to model direction wetting. PMID:23944550

Jansen, H Patrick; Sotthewes, Kai; van Swigchem, Jeroen; Zandvliet, Harold J W; Kooij, E Stefan

2013-07-15

370

Modeling of transformers using circuit simulators  

NASA Astrophysics Data System (ADS)

Transformers of two different designs, an unencapsulated pot core and an encapsulated toroidal core, have been modeled for circuit analysis with circuit simulation tools. We selected MicroSim's PSPICE and Anology's SABER as the simulation tools and used experimental BH Loop and network analyzer measurements to generate the needed input data. The models are compared for accuracy and convergence using the circuit simulators. Results are presented which demonstrate the effects on circuit performance from magnetic core losses, eddy currents, and mechanical stress on the magnetic cores.

Archer, W. E.; Deveney, M. F.; Nagel, R. L.

371

Modeling of transformers using circuit simulators  

SciTech Connect

Transformers of two different designs; and unencapsulated pot core and an encapsulated toroidal core have been modeled for circuit analysis with circuit simulation tools. We selected MicroSim`s PSPICE and Anology`s SABER as the simulation tools and used experimental BH Loop and network analyzer measurements to generate the needed input data. The models are compared for accuracy and convergence using the circuit simulators. Results are presented which demonstrate the effects on circuit performance from magnetic core losses, eddy currents, and mechanical stress on the magnetic cores.

Archer, W.E.; Deveney, M.F.; Nagel, R.L.

1994-07-01

372

Coupled Model Simulation of Snowfall Events over the Black Hills.  

NASA Astrophysics Data System (ADS)

Numerical simulations of two snowfall events over the Black Hills of South Dakota are made to demonstrate the use and potential of a coupled atmospheric and land surface model. The Coupled Atmospheric-Hydrologic Model System was used to simulate a moderate topographic snowfall event of 10-11 April 1999 and a blizzard event of 18-23 April 2000. These two cases were chosen to provide a contrast of snowfall amounts, locations, and storm dynamics. The model configuration utilized a nested grid with an outer grid of 16-km spacing driven by numerical forecast model data and an inner grid of 4 km centered over the Black Hills region. Simulations for the first case were made with the atmospheric model, the Advanced Regional Prediction System (ARPS) alone, and with ARPS coupled with the National Center for Atmospheric Research Land Surface Model (LSM). Results indicated that the main features of the precipitation pattern were captured by ARPS alone. However, precipitation amounts were greatly overpredicted. ARPS coupled with LSM produced a very similar precipitation pattern, but with precipitation amounts much closer to those observed. The coupled model also permits simulation of the resulting snow cover and snowmelt. Simulated percentage snow melting occurred somewhat more rapidly than that of the observed. Snow-rain discrimination may be taken from the precipitation type falling out of the atmospheric model based on the microphysical parameterization, or by the use of a surface temperature criteria, as used in most large-scale models. The resulting snow accumulation patterns and amounts were nearly identical. The coupled model configuration was used to simulate the second case. In this case the simulated precipitation and snow depth maximum over the eastern Black Hills were biased to the east and north by about 24 km. The resulting spatial correlation of the simulated snowfall and observations was only 0.37. If this bias is removed, the shifted pattern over the Black Hills region has a correlation of 0.68. Snow-melting patterns for 21 and 22 April appeared reasonable, given the spatial bias in the snowfall simulation.

Wang, J.; Hjelmfelt, M. R.; Capehart, W. J.; Farley, R. D.

2003-06-01

373

Modeling and simulation of nanoscale devices with a desktop supercomputer  

NASA Astrophysics Data System (ADS)

Designing nanoscale devices presents a number of unique challenges. As device features shrink, the computational demands of the simulations necessary to accurately model them increase significantly. This is a result of not only the increasing level of detail in the device design itself, but also the need to use more accurate models. The approximations that are generally made when dealing with larger devices break down as feature sizes decrease. This can be seen in the optics field when contrasting the complexity of physical optics models with those requiring a rigorous solution to Maxwell's equations. This added complexity leads to more demanding calculations, stressing computational resources and driving research to overcome these limitations. There are traditionally two means of improving simulation times as model complexity grows beyond available computational resources: modifying the underlying algorithms to maintain sufficient precision while reducing overall computations and increasing the power of the computational system. In this paper, we explore the latter. Recent advances in commodity hardware technologies, particularly field-programmable gate arrays (FPGAs) and graphics processing units (GPUs), have allowed the creation of desktop-style devices capable of outperforming PC clusters. We will describe the key hardware technologies required to build such a device and then discuss their application to the modeling and simulation of nanophotonic devices. We have found that FPGAs and GPUs can be used to significantly reduce simulation times and allow for the solution of much large problems.

Kelmelis, Eric J.; Durbano, James P.; Humphrey, John R.; Ortiz, Fernando E.; Curt, Petersen F.

2006-09-01

374

Dynamic modeling and optimizations of mechanical prosthetic arm by simulation technique  

Microsoft Academic Search

Simulation of a mechanical system incorporating the biological control has drawn the fascination of researchers' interest in the research field of advanced prosthetic control and artificial intelligence. This paper generates the idea of modeling of a mechanical prosthetic arm via some heuristic applications of simulation techniques. The introductory part of the paper shows the clinical study of an upper limb

Biswarup Neogi; Soumya Ghosal; Sinchan Ghosh; Tridib Kumar Bose; Achintya Das

2012-01-01

375

Chapter 4 Modeling and Simulation  

Microsoft Academic Search

Quantitative Modeling has been the basis of most of the initial research in operations, labeled as Operational Research in Europe, and was the basis of initial management consulting and Operations Research in the USA. Initially, quantitative modeling in Operational Research was oriented very much towards solving real-life problems in operations management rather than towards developing scientific knowledge. Later however, especially

Duane S. Boning; Okumu Ouma

1999-01-01

376

Advanced Placement: An Exemplary Honors Model  

Microsoft Academic Search

This article, examining honors and Advanced Placement Courses, is the second in a series reporting on the Richardson Study, a national investigation of the educational opportunities available to able learners, being conducted by the Sid W. Richardson Foundation in Fort Worth, Texas. In addition to conducting a national survey and visiting schools throughout the country, I gathered information for the

June Cox

1984-01-01

377

Predicting Career Advancement with Structural Equation Modelling  

ERIC Educational Resources Information Center

Purpose: The purpose of this paper is to use the authors' prior findings concerning basic employability skills in order to determine which skills best predict career advancement potential. Design/methodology/approach: Utilizing survey responses of human resource managers, the employability skills showing the largest relationships to career…

Heimler, Ronald; Rosenberg, Stuart; Morote, Elsa-Sofia

2012-01-01

378

Predicting Career Advancement with Structural Equation Modelling  

ERIC Educational Resources Information Center

|Purpose: The purpose of this paper is to use the authors' prior findings concerning basic employability skills in order to determine which skills best predict career advancement potential. Design/methodology/approach: Utilizing survey responses of human resource managers, the employability skills showing the largest relationships to career…

Heimler, Ronald; Rosenberg, Stuart; Morote, Elsa-Sofia

2012-01-01

379

Advances in multi-scale modeling of solidification and casting processes  

NASA Astrophysics Data System (ADS)

The development of the aviation, energy and automobile industries requires an advanced integrated product/process R&D systems which could optimize the product and the process design as well. Integrated computational materials engineering (ICME) is a promising approach to fulfill this requirement and make the product and process development efficient, economic, and environmentally friendly. Advances in multi-scale modeling of solidification and casting processes, including mathematical models as well as engineering applications are presented in the paper. Dendrite morphology of magnesium and aluminum alloy of solidification process by using phase field and cellular automaton methods, mathematical models of segregation of large steel ingot, and microstructure models of unidirectionally solidified turbine blade casting are studied and discussed. In addition, some engineering case studies, including microstructure simulation of aluminum casting for automobile industry, segregation of large steel ingot for energy industry, and microstructure simulation of unidirectionally solidified turbine blade castings for aviation industry are discussed.

Liu, Baicheng; Xu, Qingyan; Jing, Tao; Shen, Houfa; Han, Zhiqiang

2011-04-01

380

Simulating data processing for an Advanced Ion Mobility Mass Spectrometer  

SciTech Connect

We have designed and implemented a Cray XD-1-based sim- ulation of data capture and signal processing for an ad- vanced Ion Mobility mass spectrometer (Hadamard trans- form Ion Mobility). Our simulation is a hybrid application that uses both an FPGA component and a CPU-based soft- ware component to simulate Ion Mobility mass spectrome- try data processing. The FPGA component includes data capture and accumulation, as well as a more sophisticated deconvolution algorithm based on a PNNL-developed en- hancement to standard Hadamard transform Ion Mobility spectrometry. The software portion is in charge of stream- ing data to the FPGA and collecting results. We expect the computational and memory addressing logic of the FPGA component to be portable to an instrument-attached FPGA board that can be interfaced with a Hadamard transform Ion Mobility mass spectrometer.

Chavarría-Miranda, Daniel; Clowers, Brian H.; Anderson, Gordon A.; Belov, Mikhail E.

2007-11-03

381

MCNP full-core modeling of the advanced test reactor  

Microsoft Academic Search

A full-core Monte Carlo neutron and photon (MCNP) transport model has been completed for the advanced test reactor (ATR) at Idaho National Engineering Laboratory. This new model is a complete three-dimensional model that represents fuel elements, core structures, and target regions in adequate detail. The model can be used in evaluating heating and reaction rates in various target regions of

S. S. Kim; S. N. Jahshan; R. B. Nielson

1993-01-01

382

Advanced wellbore thermal simulator: GEOTEMP2 user manual  

SciTech Connect

GEOTEMP2 is a wellbore thermal simulator designed for geothermal well drilling and production problems. GEOTEMP2 includes the following features: fully transient heat conduction, wellbore fluid flow options, well completion options, and drilling-production histories. The data input format is given, along with input examples and comments on special features of the input. Ten examples that illustrate all of the flowing options and input options in GEOTEMP2 are included.

Mitchell, R.F.

1982-02-01

383

Using advanced industrial robotics for spacecraft Rendezvous and Docking simulation  

Microsoft Academic Search

One of the most challenging and risky missions for spacecraft is to perform Rendezvous and Docking (RvD) autonomously in space. To ensure a safe and reliable operation, such a mission must be carefully designed and thoroughly verified before a real space mission can be launched. This paper describes a new, robotics-based, hardware-in-the-loop RvD simulation facility which uses two industrial robots

Toralf Boge; Ou Ma

2011-01-01

384

ADVANCES IN COMPREHENSIVE GYROKINETIC SIMULATIONS OF TRANSPORT IN TOKAMAKS  

SciTech Connect

A continuum global gyrokinetic code GYRO has been developed to comprehensively simulate core turbulent transport in actual experimental profiles and enable direct quantitative comparisons to the experimental transport flows. GYRO not only treats the now standard ion temperature gradient (ITG) mode turbulence, but also treats trapped and passing electrons with collisions and finite {beta}, equilibrium ExB shear stabilization, and all in real tokamak geometry. Most importantly the code operates at finite relative gyroradius ({rho}{sub *}) so as to treat the profile shear stabilization and nonlocal effects which can break gyroBohm scaling. The code operates in either a cyclic flux-tube limit (which allows only gyroBohm scaling) or a globally with physical profile variation. Rohm scaling of DIII-D L-mode has been simulated with power flows matching experiment within error bars on the ion temperature gradient. Mechanisms for broken gyroBohm scaling, neoclassical ion flows embedded in turbulence, turbulent dynamos and profile corrugations, plasma pinches and impurity flow, and simulations at fixed flow rather than fixed gradient are illustrated and discussed.

WALTZ RE; CANDY J; HINTON FL; ESTRADA-MILA C; KINSEY JE

2004-10-01

385

Genome Reshuffling for Advanced Intercross Permutation (GRAIP): simulation and permutation for advanced intercross population analysis  

Microsoft Academic Search

BACKGROUND: Advanced intercross lines (AIL) are segregating populations created using a multi-generation breeding protocol for fine mapping complex trait loci (QTL) in mice and other organisms. Applying QTL mapping methods for intercross and backcross populations, often followed by naive permutation of individuals and phenotypes, does not account for the effect of AIL family structure in which final generations have been

Jeremy L. Peirce; Karl W. Broman; Lu Lu; Elissa J. Chesler; Guomin Zhou; David C. Airey; Amanda E. Birmingham; Robert W. Williams

2008-01-01

386

Genome Reshuffling for Advanced Intercross Permutation (GRAIP): Simulation and Permutation for Advanced Intercross Population Analysis  

Microsoft Academic Search

BackgroundAdvanced intercross lines (AIL) are segregating populations created using a multi-generation breeding protocol for fine mapping complex trait loci (QTL) in mice and other organisms. Applying QTL mapping methods for intercross and backcross populations, often followed by naïve permutation of individuals and phenotypes, does not account for the effect of AIL family structure in which final generations have been expanded

Jeremy L. Peirce; Karl W. Broman; Lu Lu; Elissa J. Chesler; Guomin Zhou; David C. Airey; Amanda E. Birmingham; Robert W. Williams

2008-01-01

387

DAIS Models Simulation System (DMSS)  

NASA Astrophysics Data System (ADS)

The DMSS software support effort enhanced the capabilities and value of DMSS by accomplishing the following four objectives: (1) Addition of VATS/Pave Tack and Maverick Missile models; (2) Enhancing the existing software; (3) Creating meaningful, up-to-date documentation; and (4) Providing comprehensive training. The new models were developed using top-down structuring techniques and were implemented in RATFOR (a structured FORTRAN preprocessor). The existing models were restructured using top-down structuring techniques, RATFOR, and meaningful comments. The documentation was updated to adhere to MIL-STD-483 and 490.

Brewer, A. C.

1981-05-01

388

Aligning Simulation Models of Biological Attacks  

Microsoft Academic Search

We aligned two fundamentally different models of disea se transmission after a bioterrorist attack: a multi-agent model (BioWar) and the conventio nal Susceptible-Infected-Recovered (SIR) model. The purpose of this alignment is part of a gre ater validation process for BioWar. We conducted two model alignment studies based on smallpox and anthrax attack simulations. From these two studies we were able

Li-Chiou Chen; Kathleen M. Carley; Boris Kaminsky; Tiffany Tummino; Elizabeth Casman; Douglas Fridsma; Alex Yahja

389

Advanced multi-phase flow CFD model development for solid rocket motor flowfield analysis  

Microsoft Academic Search

It is known that the simulations of solid rocket motor internal flow field with AL-based propellants require complex multi-phase turbulent flow model. The objective of this study is to develop an advanced particulate multi-phase flow model which includes the effects of particle dynamics, chemical reaction and hot gas flow turbulence. The inclusion of particle agglomeration, particle\\/gas reaction and mass transfer,

Paul Liaw; Y. S. Chen; H. M. Shang; Denise Doran

1993-01-01

390

Attentional Models of Multitask Pilot Performance Using Advanced Display Technology  

Microsoft Academic Search

In the first part of the reported research, 12 instrument-rated pilots flew a highfidelity simulation, in which air traffic control presentation of auditory (voice) information regarding traffic and flight parameters was compared with advanced display technology presentation of equivalent information regarding traffic (cockpit display of traffic information) and flight parameters (data link display). Redundant combinations were also examined while pilots

Christopher D. Wickens; Juliana Goh; John Helleberg; William J. Horrey; Donald A. Talleur

2003-01-01

391

A Simulation-Based Process Model for Managing Complex Design Projects  

Microsoft Academic Search

This paper presents a process modeling and analysis technique for managing complex design projects using advanced simulation. The model computes the probability distribution of lead time in a stochastic, resource-constrained project network where iterations take place among sequential, parallel, and overlapped tasks. The model uses the design structure matrix representation to capture the information flows between tasks. We use a

Soo-Haeng Cho; Steven D. Eppinger

2005-01-01

392

Center for Advanced Transportation Systems Simulation Annual Report. Reporting Period July 1, 2006 to June 30, 2007.  

National Technical Information Service (NTIS)

The Center for Advanced Transportation Systems Simulation, known as CATSS, was established with the theme of applying advanced technologies to enhance the planning, design, operation, management, and safety of transportation systems. It is the goal of the...

E. Radwan J. Selter

2007-01-01

393

Atmospheric model intercomparison project: Monsoon simulations  

SciTech Connect

The simulation of monsoons, in particular the Indian summer monsoon, has proven to be a critical test of a general circulation model`s ability to simulate tropical climate and variability. The Monsoon Numerical Experimentation Group has begun to address questions regarding the predictability of monsoon extremes, in particular conditions associated with El Nino and La Nina conditions that tend to be associated with drought and flood conditions over the Indian subcontinent, through a series of seasonal integrations using analyzed initial conditions from successive days in 1987 and 1988. In this paper the authors present an analysis of simulations associated with the Atmospheric Model Intercomparison Project (AMIP), a coordinated effort to simulate the 1979--1988 decade using standardized boundary conditions with approximately 30 atmospheric general circulation models. The 13 models analyzed to date are listed. Using monthly mean data from these simulations they have calculated indices of precipitation and wind shear in an effort to access the performance of the models over the course of the AMIP decade.

Sperber, K.R. [Lawrence Livermore National Lab., CA (United States). Program for Climate Model Diagnosis and Intercomparison; Palmer, T.N. [European Centre for Medium-Range Weather Forecasts, Reading (United Kingdom)

1994-06-01

394

Research on Hardware-in-the-Loop Simulation for Advanced Front-Lighting System  

Microsoft Academic Search

Due to the poor adaptability of the traditional vehicle headlights under some conditions such as vehiclepsilas speed at night, road type and weather situation, the Advanced Front-lighting System (AFS) has been widely concerned in the world. Based on the analysis of the advanced front-lighting's related characters and the hardware-in-the-loop's significance, the hardware-in-the-loop simulation for AFS based on the xPC technology

Qing Wu; Ling Lei; Jianlin Chen; Weifeng Wang

2008-01-01

395

Oil market simulation model: User's manual  

SciTech Connect

The Oil Market Simulation (OMS) model is a LOTUS 1-2-3 spreadsheet that simulates the world oil market. OMS is an annual model that projects the world oil market through the year 2010 from a data base that begins in 1979. The geographic coverage includes all market economies, with net imports from the centrally planned economies taken as an assumption. The model estimates the effects of price changes on oil supply and demand and computes an oil price path over time that allows supply and demand to remain in balance within the market economies area as a whole. 2 figs., 2 tabs.

Not Available

1990-06-01

396

Oil Market Simulation model user's manual  

SciTech Connect

The Oil Market Simulation (OMS) model is a LOTUS 1-2-3 spreadsheet that simulates the world oil market. OMS is an annual model that projects the world oil market through the year 2010 from a data base that begins in 1979. The geographic coverage includes all market economies, with net imports from the centrally planned economies taken as an assumption. The model estimates the effects of price changes an oil supply and demand and computes an oil price path over time that allows supply and demand to remain in balance within the market economies area as a whole.

Not Available

1991-11-01

397

Estimating solar radiation for plant simulation models  

SciTech Connect

Five algorithms producing daily solar radiation surrogates using daily temperatures and rainfall were evaluated using measured solar radiation data for seven U.S. locations. The algorithms were compared both in terms of accuracy of daily solar radiation estimates and terms of response when used in a plant growth simulation model (CERES-wheat). Requirements for accuracy of solar radiation for plant growth simulation models are discussed. One algorithm is recommended as being best suited for use in these models when neither measured nor satellite estimated solar radiation values are available.

Hodges, T.; French, V.; Leduc, S.

1985-01-01

398

Univariate input models for stochastic simulation  

Microsoft Academic Search

Techniques are presented for modeling and randomly sampling many of the multivariate probabilistic input processes that drive discrete-event simulation experiments. Emphasis is given to bivariate and trivariate extensions of the univariate beta, Johnson, and Bézier dist ribution families because of the flexibility of these families to model a wide range of shapes for the marginal distributions while also representing the

Michael E. Kuhl; Julie S. Ivy; Emily K. Lada; Natalie M. Steiger; Mary Ann Flanigan Wagner; James R. Wilson

2010-01-01

399

Modeling and simulation of dielectric elastomer actuators  

Microsoft Academic Search

Dielectric elastomers are used as base material for so-called electroactive polymer (EAP) actuators. A procedure and a specific constitutive model (for the acrylic elastomer VHB 4910) are presented in this work for finite element modeling and simulation of dielectric elastomer actuators of general shape and set-up. The Yeoh strain energy potential and the Prony series are used for describing the

Michael Wissler; Edoardo Mazza

2005-01-01

400

Power transformers model used for inverters simulations  

Microsoft Academic Search

This paper intends to present a model of power transformers used in simulation of power inverters. Electromagnetic induction refers to the phenomenon by witch electric current is generated in a closed circuit by the fluctuation of current in another circuit placed next to it. For modeling of power transformers, we implemented a Matlab software, based on mathematical equations who describe

Adrian Taut; Ovidiu Pop; Serban Lungu

2010-01-01

401

Forest landscape management modeling using simulated annealing  

Microsoft Academic Search

This paper presents a new landscape management model using a simulated annealing approach. The model is capable of achieving target landscape structure, in the form of composition and configuration objectives, in a near optimal fashion by spatially and temporally scheduling treatment interventions. Management objectives and constraints are identified in an objective function. Penalty cost functions for each objective establish common

Emin Z. Baskent; Glen A. Jordan

2002-01-01

402

Dynamic centrifugal compressor model for system simulation  

Microsoft Academic Search

A dynamic model of a centrifugal compressor capable of system simulation in the virtual test bed (VTB) computational environment is presented. The model is based on first principles, i.e. the dynamic performance including the losses is determined from the compressor geometry and not from the experimentally determined characteristic performance curves. In this study, the compressor losses, such as incidence and

Wei Jiang; Jamil Khan; Roger A. Dougal

2006-01-01

403

Modeling Individual Behaviors in Crowd Simulation  

Microsoft Academic Search

This paper presents a model for studying the impact of individual agents characteristics in emergent groups, on the evacuation efficiency as a result of local interactions. We used the physically based model of crowd simulation proposed by Helbing (6) and generalized it in order to deal with different individualities for agent and group behaviors. In addition, we present a framework

Adriana Braun; Soraia Raupp Musse; Luiz Paulo Luna De Oliveira; Bardo E. J. Bodmann

2003-01-01

404

Hierarchical modeling for discrete event simulation (panel)  

Microsoft Academic Search

This panel session is to discuss the issues and current research in hierarchical modeling for discrctc event simulation. Three academic researchers are to briefly describe their research in hierarchical modeling and the issues and one industrial practitioner will present the issues from a user’s perspective.

Robert G. Sargent; Joe H. Mize; David H. Withers; Bernard P. Zeigler

1993-01-01

405

Hierarchical Modeling for Discrete Event Simulation (Panel)  

Microsoft Academic Search

This panel session is 1.0 discuss the issucs and current research in hierarchical modeling for discrete event simulation. Three academic researchcrs are to briefly describe their research in hicrarchical modeling and the issues and one industrial practitioncr will present the issues from a user's perspcctivc. 1 BACKGROUND

R. G. Sargent; J. H. Mize; D. H. Withers; B. P. Zeigler

1993-01-01

406

Regularization modeling for large-eddy simulation  

Microsoft Academic Search

A new modeling approach for large-eddy simulation (LES) is obtained by combining a ``regularization principle'' with an explicit filter and its inversion. This regularization approach allows a systematic derivation of the implied subgrid model, which resolves the closure problem. The central role of the filter in LES is fully restored, i.e., both the interpretation of LES predictions in terms of

Bernard J. Geurts; Darryl D. Holm

2003-01-01

407

Deformable models for laparoscopic surgery simulation  

Microsoft Academic Search

This paper introduces a method for handling deformation in interactive, real time computer graphics simulations which involve deformable objects and require a high degree of visual realism. Our proposal, the virtual structure, is a “divide and conquer” approach, which combines a novel physical model with a geometric modelling utilizes the theory of elasticity and Newtonian mechanics, applied by a numerical

Konstantinos Moutsopoulos; Duncan Gillies

1997-01-01

408

Modeling and simulation for control design  

Microsoft Academic Search

This paper documents the use of recently developed symbolic software for modeling of a US Army M113 armoured personnel carrier and numerical simulation of the generated nonlinear ordinary differential equations of motion. A brief discussion of the symbolic software used for modeling, analysis, and control system design of multiple body systems is presented. This software is used to create a

Eric Salter; Chris LaVigna; Mike Mattice; Mary Devito; Robert Testa

1998-01-01

409

Advanced Development Model of a Mobile Meteorological Station.  

National Technical Information Service (NTIS)

The report furnished a description of the advanced development model of a Mobile Meteorological Station. In this report the choice of particular sensors is discussed, and the data processor, forward area display unit and printer are described. (Author)

J. M. Moran M. Zinchuk G. R. Guerin E. A. Charron D. W. Bagley

1968-01-01

410

ADVANCES IN COMPREHENSIVE GYROKINETIC SIMULATIONS OF TRANSPORT IN TOKAMAKS  

SciTech Connect

A continuum global gyrokinetic code GYRO has been developed to comprehensively simulate core turbulent transport in actual experimental profiles and enable direct quantitative comparisons to the experimental transport flows. GYRO not only treats the now standard ion temperature gradient (ITG) mode turbulence, but also treats trapped and passing electrons with collisions and finite {beta}, equilibrium ExB shear stabilization, and all in real tokamak geometry. Most importantly the code operates at finite relative gyroradius ({rho}{sub *}) so as to treat the profile shear stabilization and nonlocal effects which can break gyroBohm scaling. The code operates in either a cyclic flux-tube limit (which allows only gyroBohm scaling) or globally with physical profile variation. Bohm scaling of DIII-D L-mode has been simulated with power flows matching experiment within error bars on the ion temperature gradient. Mechanisms for broken gyroBohm scaling, neoclassical ion flows embedded in turbulence, turbulent dynamos and profile corrugations, are illustrated.

WALTZ,R.E; CANDY,J; HINTON,F.L; ESTRADA-MILA,C; KINSEY,J.E

2004-10-01

411

Coupling an Advanced Land Surface Hydrology Model with the Penn State NCAR MM5 Modeling System. Part II: Preliminary Model Validation  

Microsoft Academic Search

A number of short-term numerical experiments conducted by the Penn State-NCAR fifth-generation Mesoscale Model (MM5) coupled with an advanced land surface model, alongside the simulations coupled with a simple slab model, are verified with observations. For clear sky day cases, the MM5 model gives reasonable estimates of radiation forcing at the surface with solar radiation being slightly overestimated probably due

Fei Chen; Jimy Dudhia

2001-01-01

412

DAIS Models Simulation System (DMSS).  

National Technical Information Service (NTIS)

The DMSS software support effort enhanced the capabilities and value of DMSS by accomplishing the following four objectives: (1) Addition of VATS/Pave Tack and Maverick Missile models; (2) Enhancing the existing software; (3) Creating meaningful, up-to-da...

A. C. Brewer

1981-01-01

413

Five forest harvesting simulation models, part 1: modeling characteristics  

SciTech Connect

This paper is the first of two describing the conclusions from a study to determine the state of the art in timber harvesting computer simulation modeling. Five models were evaluated -- Forest Harvesting Simulation Model (FHSM), Full Tree Field Chipping (FTFC), Harvesting System Simulator (HSS), Simulation Applied to Logging Systems (SAPLOS), and Timber Harvesting and Transport Simulator (THATS) -- for their potential use in southern forest harvesting operations. In Part I, modeling characteristics and overall model philosophy are identified and illustrated. This includes a detailed discussion of the wood flow process in each model, accounting strategies for productive/non-productive times, performance variables, and the different types of harvesting systems modelable. In Part II we discuss user implementation problems. Those dealt with in detail are: What questions can be asked of the model. What are the modeling tradeoffs, and how do they impact on the analysis. What are the computer skills necessary to effectively work with the model. What computer support is needed. Are the models operational. The results provide a good picture of the state of the art in timber harvesting computer simulation. Much learning has occurred in the generation of these models, and many modeling and implementation problems have been uncovered, some of which remain unsolved. Hence, the user needs to examine closely the model and the intended application so that results will represent usable, valid data. It is recommended that the development of timber harvesting computer simulation modeling continue, so that existing and proposed timber harvesting strategies can be adequately evaluated. A set of design criteria are proposed. (Refs. 21).

Goulet, D.V.; Iff, R.H.; Sirois, D.L.

1980-01-01

414

Power electronics system modeling and simulation  

SciTech Connect

This paper introduces control system design based softwares, SIMNON and MATLAB/SIMULINK, for power electronics system simulation. A complete power electronics system typically consists of a rectifier bridge along with its smoothing capacitor, an inverter, and a motor. The system components, featuring discrete or continuous, linear or nonlinear, are modeled in mathematical equations. Inverter control methods,such as pulse-width-modulation and hysteresis current control, are expressed in either computer algorithms or digital circuits. After describing component models and control methods, computer programs are then developed for complete systems simulation. Simulation results are mainly used for studying system performances, such as input and output current harmonics, torque ripples, and speed responses. Key computer programs and simulation results are demonstrated for educational purposes.

Lai, Jih-Sheng

1994-12-31

415

Modeling and simulation for the semiconductor and optoelectronic industries  

SciTech Connect

This is the final report of a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Semiconductor technology development costs and time-to-market pressures are rapidly increasing with each new technology generation. However, computer-aided integrated circuit (IC) design tools have been shown to reduce IC design time and overall costs, and the micro- and opto-electronics industries have come to believe that enlarging the modeling scope to include new materials processing simulators will have a corresponding profound impact on manufacturing. This project sought to assess the feasibility of building a suite of predictive advanced technology modeling and simulation tools for use by the semiconductor industry.

Cartwright, D.; Albers, R.; George, D. [Los Alamos National Lab., NM (United States)] [and others

1996-06-01

416

Towards a computer aided simulation model engineering (CASME) environment  

Microsoft Academic Search

There is increasing focus on the model development aspect of systems simulation, termed “Model Engineering”. Current software development tools consist primarily of CASE tools with simulation extensions or simulation tools with model-building extensions. The need for a Computer-Aided Simulation Model Engineering (CASME) environment is identified and discussed. In particular, a CASME environment should support a model building process based on

Joel J. Luna

1993-01-01

417

A future Outlook: Web based Simulation of Hydrodynamic models  

NASA Astrophysics Data System (ADS)

Despite recent advances to present simulation results as 3D graphs or animation contours, the modeling user community still faces some shortcomings when trying to move around and analyze data. Typical problems include the lack of common platforms with standard vocabulary to exchange simulation results from different numerical models, insufficient descriptions about data (metadata), lack of robust search and retrieval tools for data, and difficulties to reuse simulation domain knowledge. This research demonstrates how to create a shared simulation domain in the WWW and run a number of models through multi-user interfaces. Firstly, meta-datasets have been developed to describe hydrodynamic model data based on geographic metadata standard (ISO 19115) that has been extended to satisfy the need of the hydrodynamic modeling community. The Extended Markup Language (XML) is used to publish this metadata by the Resource Description Framework (RDF). Specific domain ontology for Web Based Simulation (WBS) has been developed to explicitly define vocabulary for the knowledge based simulation system. Subsequently, this knowledge based system is converted into an object model using Meta Object Family (MOF). The knowledge based system acts as a Meta model for the object oriented system, which aids in reusing the domain knowledge. Specific simulation software has been developed based on the object oriented model. Finally, all model data is stored in an object relational database. Database back-ends help store, retrieve and query information efficiently. This research uses open source software and technology such as Java Servlet and JSP, Apache web server, Tomcat Servlet Engine, PostgresSQL databases, Protégé ontology editor, RDQL and RQL for querying RDF in semantic level, Jena Java API for RDF. Also, we use international standards such as the ISO 19115 metadata standard, and specifications such as XML, RDF, OWL, XMI, and UML. The final web based simulation product is deployed as Web Archive (WAR) files which is platform and OS independent and can be used by Windows, UNIX, or Linux. Keywords: Apache, ISO 19115, Java Servlet, Jena, JSP, Metadata, MOF, Linux, Ontology, OWL, PostgresSQL, Protégé, RDF, RDQL, RQL, Tomcat, UML, UNIX, Windows, WAR, XML

Islam, A. S.; Piasecki, M.

2003-12-01

418

Advances in petascale kinetic plasma simulation with VPIC and Roadrunner  

SciTech Connect

VPIC, a first-principles 3d electromagnetic charge-conserving relativistic kinetic particle-in-cell (PIC) code, was recently adapted to run on Los Alamos's Roadrunner, the first supercomputer to break a petaflop (10{sup 15} floating point operations per second) in the TOP500 supercomputer performance rankings. They give a brief overview of the modeling capabilities and optimization techniques used in VPIC and the computational characteristics of petascale supercomputers like Roadrunner. They then discuss three applications enabled by VPIC's unprecedented performance on Roadrunner: modeling laser plasma interaction in upcoming inertial confinement fusion experiments at the National Ignition Facility (NIF), modeling short pulse laser GeV ion acceleration and modeling reconnection in magnetic confinement fusion experiments.

Bowers, Kevin J [Los Alamos National Laboratory; Albright, Brian J [Los Alamos National Laboratory; Yin, Lin [Los Alamos National Laboratory; Daughton, William S [Los Alamos National Laboratory; Roytershteyn, Vadim [Los Alamos National Laboratory; Kwan, Thomas J T [Los Alamos National Laboratory

2009-01-01

419

Hydrological validation of multifractal rainfall simulation models  

NASA Astrophysics Data System (ADS)

The observed scaling invariance properties of rainfall time series have often been put forward to justify the choice of multifractal (scaling) models for rainfall stochastic modelling. These models are nevertheless seldom validated on real hydrological applications. Two types of multifractal models - the first one with a Log-Poisson generator and the second one with a uniform generator - were calibrated on a 8 year point rainfall series with a five minute time step. The results obtained with the rainfall series simulated with these models on two hydrological applications (the computation of intensity-duration-frequency, IDF, curves and the conception of a urban drainage storage volume) were compared with those obtained with the original measured rainfall series. The disagreements reveal some limitations of the multifractal models. On the one hand, using the vocabulary of the multifractalists, the models are calibrated on the basis of the statistical properties of the simulated undressed series while the IDF curves are computed on the dressed series. The statistical properties of both types of series clearly differ if a canonical model is used : here the model with the Log-Poisson generator. On the other hand, the optimal dimensions of the storage volume depend on the shape of the hyetographs. The discordances between the volumes obtained with the simulated or measured rainfall series indicate that the temporal structure of the simulated rainfall intensity series (i.e. the shapes of the simulated hyetographs) are not comparable with the one of the measured series. As a conclusion, multifractal models appear to reproduce accuratly only some of the properties of the real measured series. Their appropriateness should not be a priori asserted but verified for each considered application.

Mouhous, N.; Gaume, E.; Andrieu, H.

2003-04-01

420

Recent Improvements to an Advanced Atmospheric Transport Modeling System  

SciTech Connect

The Atmospheric Technologies Group (ATG) has developed an advanced atmospheric modeling capability using the Regional Atmospheric Modeling System (RAMS) and a stochastic Lagrangian particle dispersion model (LPDM) for operational use at the Savannah River Site (SRS). For local simulations concerning releases from the Central Savannah River Area (CSRA), RAMS is run in a nested grid configuration with horizontal grid spacing of 8 and 2 km for each grid, with 6-hr forecasts updated every 3 hours. An interface to allow for easy user access to LPDM had been generated, complete with post-processing results depicting surface concentration, deposition, and a variety of dose quantities. A prior weakness in this approach was that observations from the SRS tower network were only incorporated into the three-dimensional modeling effort during the initialization process. Thus, if the forecasted wind fields were in error, the resulting plume predictions would also be erroneous. To overcome this shortcoming, the procedure for generating RAMS wind fields and reading them into LPDM has been modified such that SRS wind measurements are blended with the predicted three-dimensional wind fields from RAMS using the Barnes technique. In particular, the horizontal components in RAMS are replaced with the observed values at a series of 8 towers that exist within the SRS boundary (covering {approx}300 km{sup 2}). Even though LPDM is currently configured to account only for radioactive releases, it was used in a recent chlorine gas release to generate plume concentrations based on unit releases from the site of a train accident in Graniteville, South Carolina. This information was useful to local responders as an indication of potential protective actions downwind of the release.

Buckley, R. L.; Hunter, C. H.

2005-10-24

421

Modeling Drawbeads in Deep Drawing Simulations  

Microsoft Academic Search

The numerical simulation has become an indispensable tool in the design, production and process set up of deep drawn parts.\\u000a The advantages of these tools are nowadays well known. If the numerical model correctly describes both the technological procedure\\u000a and process parameters, the use of numerical simulation allows to save time, money and effort. One of the challenges to guarantee

J. L. Alves; M. C. Oliveira; L. F. Menezes

422

Wind power forecasting using advanced neural networks models  

Microsoft Academic Search

In this paper, an advanced model, based on recurrent high order neural networks, is developed for the prediction of the power output profile of a wind park. This model outperforms simple methods like persistence, as well as classical methods in the literature. The architecture of a forecasting model is optimised automatically by a new algorithm, that substitutes the usually applied

G. N. Kariniotakis; G. S. Stavrakakis; E. F. Nogaret

1996-01-01

423

Advances in a cognitive behavioural model of body dysmorphic disorder  

Microsoft Academic Search

Body dysmorphic disorder (BDD) is the most distressing and handicapping of all the body image disorders. A cognitive behavioural model of BDD is discussed which incorporates evidence from recent studies and advances in the author’s 1996 conceptual model. The model aims to understand the maintenance of symptoms in BDD, to assist in the process of engagement of therapy and to

David Veale

2004-01-01

424

Virtual Environments for Advanced Modeling: Conceptual Foundations for Research  

Microsoft Academic Search

In this concept paper, we advocate for a paradigm shift in computational modeling. Advanced modeling should conceive new computational languages and models to describe real-life phenomena and solve real-life problems. Moreover, it should also be used to create \\

Tung X. Bui; Hans-Juergen Sebastian; Daniel R. Dolk; Alexandre Gachet

2005-01-01

425

Modeling of fluid transients in machines. Part 2: Advanced considerations  

NASA Astrophysics Data System (ADS)

A state-of-the-art literature review is presented with emphasis on advanced mathematical modeling considerations. The following topics are discussed: modeling of turbomachinery and positive displacement machinery; dynamic coupling of machines; transient behavior of machinery systems and installations; multidimensional transients; two phase flow; interaction between wave propagation and fluid flow modes; and experimental modeling methods.

Singh, R.

1980-07-01

426

Physical models for semiconductor device simulation  

Microsoft Academic Search

Device simulation has two main purposes: to understand and to depict the physical processes in the interior of a device, and\\u000a to make reliable predictions of the behavior of the next device generation. Towards these goals, the quality of the implemented\\u000a physical models is decisive, forcing heuristic fit models to be replaced by “first-principle”-based models. Since transport\\u000a schemes using moments

Andreas Schenk

1996-01-01

427

Advanced simulation concept for power electronic systems applied to the 3-level NPC inverter  

Microsoft Academic Search

State-of-the-art high-power applications offer a high level of complexity, containing, e.g., linear, hybrid and nonlinear elements. The development of advanced control algorithms requires enhanced simulation effort featuring hybrid systems containing continuous and discrete elements. Besides a brief description of a simulation concept fulfilling these requirements and additionally minimising development time losses by program portation using an interface for control algorithms

Roman Bartelt; Carsten Heising; Martin Oettmeier; Volker Staudt; Andreas Steimel

2009-01-01

428

An Advanced PC-Cluster Based Real-Time Simulator for Power Electronics and Drives  

Microsoft Academic Search

This paper presents the development of an advanced PC-cluster based parallel and distributed real-time digital simulator. The simulator is very flexible and scalable, and is built entirely from commodity-off-the-shelf (COTS) hardware and software components. A combination of real-time Linux operating system and an ultra-fast network forms the backbone for the internal communication between the powerful processors of the Xeon-Cluster which

M. O. Faruque; V. Dinavahi

2006-01-01

429

Advanced Techniques for Modeling Avian Nest Survival  

Microsoft Academic Search

Estimation of avian nest survival has traditionally involved simple measures of apparent nest survival or Mayfield constant-nest-survival models. However, these meth- ods do not allow researchers to build models that rigorously assess the importance of a wide range of biological factors that affect nest survival. Models that incorporate greater detail, such as temporal variation in nest survival and covariates representative

Stephen J. Dinsmore; Gary C. White; Fritz L. Knopf

2002-01-01

430

[Research advances in simulating land water-carbon coupling].  

PubMed

The increasing demand of adaptive management of land, forest, and water resources under the background of global change and water resources crisis has promoted the comprehensive study of coupling ecosystem water and carbon cycles and their restrictive relations. To construct the water-carbon coupling model and to approach the ecosystem water-carbon balance and its interactive response mechanisms under climate change at multiple spatiotemporal scales is nowadays a major concern. After reviewing the coupling relationships of water and carbon at various scales, this paper explored the implications and estimation methods of the key processes and related parameters of water-carbon coupling, the construction of evapotranspiration model at large scale based on RS, and the importance of this model in water-carbon coupling researches. The applications of assimilative multivariate data in water-carbon coupling researches under future climate change scenarios were also prospected. PMID:23431808

Liu, Ning; Sun, Peng-Sen; Liu, Shi-Rong

2012-11-01

431

COMPUTATIONAL SIMULATION OF GAS TURBINES: PART I ? FOUNDATIONS OF COMPONENT-BASED MODELS  

Microsoft Academic Search

Designing and developing new aerospace propulsion systems is time-consuming and expensive. Computational simulation is a promising means for alleviating this cost, but requires a flexible software simulation system capable of integrating advanced multidisciplinary and multifidelity analysis methods, dynamically constructing arbitrary simulation models, and distributing computationally complex tasks. To address these issues, we have developed Onyx, a Java-based object-oriented domain framework

John A. Reed; Abdollah A. Afjeh

1999-01-01

432

On the Fundamental Tautology of Validating Data-Driven Models and Simulations  

Microsoft Academic Search

Recent advances in Dynamic Data Driven Application Sys- tems (DDDAS) facilitated by the present level of computational tech- nologies, as well as advances in data-driven modeling and simulation, impose the need for a critical evaluation of paradigms underlying Qual- ification, Validation and Verification (QV&V). This paper discusses the fundamental irrelevance of conventional validation procedures with re- spect to data-driven models

John Michopoulos; Sam Lambrakos

2005-01-01

433

Sharpening advanced land imager multispectral data using a sensor model  

USGS Publications Warehouse

The Advanced Land Imager (ALI) instrument on NASA's Earth Observing One (EO-1) satellite provides for nine spectral bands at 30m ground sample distance (GSD) and a 10m GSD panchromatic band. This report describes an image sharpening technique where the higher spatial resolution information of the panchromatic band is used to increase the spatial resolution of ALI multispectral (MS) data. To preserve the spectral characteristics, this technique combines reported deconvolution deblurring methods for the MS data with highpass filter-based fusion methods for the Pan data. The deblurring process uses the point spread function (PSF) model of the ALI sensor. Information includes calculation of the PSF from pre-launch calibration data. Performance was evaluated using simulated ALI MS data generated by degrading the spatial resolution of high resolution IKONOS satellite MS data. A quantitative measure of performance was the error between sharpened MS data and high resolution reference. This report also compares performance with that of a reported method that includes PSF information. Preliminary results indicate improved sharpening with the method reported here.

Lemeshewsky, G. P.

2005-01-01

434

Damage modeling for Taylor impact simulations  

NASA Astrophysics Data System (ADS)

G. I. Taylor showed that dynamic material properties could be deduced from the impact of a projectile against a rigid boundary. The Taylor anvil test became very useful with the advent of numerical simulations and has been used to infer and/or to validate material constitutive constants. A new experimental facility has been developed to conduct Taylor anvil impacts to support validation of constitutive constants used in simulations. Typically, numerical simulations are conducted assuming 2-D cylindrical symmetry, but such computations cannot hope to capture the damage observed in higher velocity experiments. A computational study was initiated to examine the ability to simulate damage and subsequent deformation of the Taylor specimens. Three-dimensional simulations, using the Johnson-Cook damage model, were conducted with the nonlinear Eulerian wavecode CTH. The results of the simulations are compared to experimental deformations of 6061-T6 aluminum specimens as a function of impact velocity, and conclusions regarding the ability to simulate fracture and reproduce the observed deformations are summarized.

Anderson, C. E., Jr.; Chocron, I. S.; Nicholls, A. E.

2006-08-01

435

Simulation and modeling for military air operations  

NASA Astrophysics Data System (ADS)

The Joint Forces Air Component Commander (JFACC) in military air operations controls the allocation of resources (wings, squadrons, air defense systems, AWACS) to different geographical locations in the theater of operations. The JFACC mission is to define a sequence of tasks for the aerospace systems at each location, and providing feedback control for the execution of these tasks in the presence of uncertainties and a hostile enemy. Honeywell Labs has been developing an innovative method for control of military air operations. The novel model predictive control (MPC) method extends the models and optimization algorithms utilized in traditional model predictive control systems. The enhancements include a tasking controller and, in a joint effort with USC, a probabilistic threat/survival map indicating high threat regions for aircraft and suggesting optimal routes to avoid these regions. A simulation/modeling environment using objected-oriented methodologies has been developed to serve as an aide to demonstrate the value of MPC and facilitate its development. The simulation/modeling environment is based on an open architecture that enables the integration, evaluation, and implementation of different control approaches. The simulation offers a graphical user interface displaying the battlefield, the control performance, and a probability map displaying high threat regions. This paper describes the features of the different control approaches and their integration into the simulation environment.

Kreichauf, Ruth D.; Bedros, Saad; Ateskan, Yusuf; Hespanha, Joao; Kizilocak, Hakan

2001-09-01

436

An investigation of the option space in conceptual building design for advanced building simulation  

Microsoft Academic Search

This article describes research conducted to gather empirical evidence on size, character and content of the option space in building design projects. This option space is the key starting point for the work of any climate engineer using building performance simulation who is supporting the design process. The underlying goal is to strengthen the role of advanced computing in building

Christian Struck; Pieter J. C. J. De Wilde; Christina J. Hopfe; Jan L. M. Hensen

2009-01-01

437

WinSRFR: Current Advances in Software for Surface Irrigation Simulation and Analysis  

Technology Transfer Automated Retrieval System (TEKTRAN)

Significant advances have been made over the last decade in the development of software for surface irrigation analysis. WinSRFR is an integrated tool that combines unsteady flow simulation with tools for system evaluation/parameter estimation, system design, and for operational optimization. Ongoi...

438

Testing Advanced Distributed Simulation for Use in Electronic Warfare Test and Evaluation.  

National Technical Information Service (NTIS)

The JADS JT&E program is an OSD sponsored Joint-Service test designed to determine how well an emerging technology - Advanced Distributed Simulation (ADS) - can support DoD test and evaluation (T&E) activities. The two-phase ADS test using an Electronic W...

D. Wright C. Harris

1998-01-01

439

Advanced AEM by Comprehensive Analysis and Modeling of System Drift  

NASA Astrophysics Data System (ADS)

The quality of the assessment of risks outgoing from environmental hazards strongly depends on the spatial and temporal distribution of the data collected in a survey area. Natural hazards generally emerge from wide areas as it is in the case of volcanoes or land slides. Conventional surface measurements are restricted to few lines or locations and often can't be conducted in difficult terrain. So they only give a spatial and temporary limited data set and therefore limit the reliability of risk analysis. Aero-geophysical measurements potentially provide a valuable tool for completing the data set as they can be performed over a wide area, even above difficult terrain within a short time. A most desirable opportunity in course of such measurements is the ascertainment of the dynamics of such potentially hazardous environmental processes. This necessitates repeated and reproducible measurements. Current HEM systems can't accomplish this adequately due to their system immanent drift and - in some cases - bad signal to noise ratio. So, to develop comprising concepts for advancing state of the art HEM-systems to a valuable tool for data acquisition in risk assessment or hydrological problems, different studies have been undertaken which form the contents of the presented work conducted in course of the project HIRISK (Helicopter Based Electromagnetic System for Advanced Environmental Risk Assessment - FWF L-354 N10, supported by the Austrian Science Fund). The methodology is based upon two paths: A - Comprehensive experimental testing on an existing HEM system serving as an experimental platform. B - The setup of a numerical model which is continuously refined according to the results of the experimental data. The model then serves to simulate the experimental as well as alternative configurations and to analyze them subject to their drift behavior. Finally, concepts for minimizing the drift are derived and tested. Different test series - stationary on ground as well as in flight - show a clear correlation between the drift in raw voltage data and temperatures of critical system components, especially in the transmitter and receiver sections. Further, the correlation with air pressure, humidity, structure geometry and static electricity has been investigated. It shows that in case of a tuned system the dependency of signal phase and amplitude on system component temperatures prevails by far and can explain most of the system drift in the voltage domain. Post-processing for compensating for the drift of HEM-data is done by two different approaches: In the first, temperature dependent transfer functions of the transmitter- and receiver section are modeled on the basis of system temperature data and a correction is derived. In an advanced approach the drift of the system is analyzed by multivariate analysis including a broader set of data (HEM-signal, transmitter-reference signal, system temperatures, humidity, air pressure, height, dynamic loads) and based on an extended model. It proves that such an analysis is able to identify residual drift sources. As a result an integrated modeling scheme is depicted which enables a better separation of signal variations caused by the system or by changes in the measurement geometry from signal variations caused by the source distribution in the ground if critical system parameters are incorporated.

Schiller, Arnulf; Klune, Klaus; Schattauer, Ingrid

2010-05-01

440

Iron Resources and Ocanic Nutrients: Advancement of Global Environment Simulations  

NASA Astrophysics Data System (ADS)

Iron limits phytoplankton growth in more than 40 percent of the oceans and is a co-limitation in the remaining 60 percent of surface waters. Moreover the paradigm of a single limiting factor for plankton blooms has given way to the concept of co-limitation by light, and the nutrient elements N, Fe, P and Si. Primary production, export into the deep sea, and CO2 uptake from the atmosphere together form the biological pump in Ocean Biogeochemical Climate Models (OBCM's). The IRONAGES project is a consortium of 12 European institutes developing more realistic OBCM's for budgeting and exchanges of both CO2 and DMS, by implementing the following improvements: (i) co-limitation by four nutrients N, Fe, P, Si simultaneously; (ii) five major bloom-forming taxonomic groups, the diatoms, calcifiers, N2-fixers, Phaecystis sp. and nano-pico-plankton; (iii) DMS(P) pathways; (iv) integrated plankton ecosystem modeling; (v) realistic global oceanic iron cycling, on basis of: (vi) iron supply from below reducing sediments; (vii) iron supply from above aeolian dust input; (viii) several chemical forms of iron in surface waters; (ix) certification of iron data in the oceans.

de Baar, H.; Ironages Team

2003-04-01

441

Advanced Modeling of Renewable Energy Market Dynamics.  

National Technical Information Service (NTIS)

This report documents a year-long academic project, presenting selected techniques for analysis of market growth, penetration, and forecasting applicable to renewable energy technologies. Existing mathematical models were modified to incorporate the effec...

G. Malikov G. Passolt K. Lloyd M. Evans R. Little

2007-01-01

442

Object-oriented qualitative simulation of human mental models of complex systems  

Microsoft Academic Search

A qualitative model of an expert's mental model of a complex system (advanced nuclear power plant) was developed from the qualitative physics of confluences and simulated using an object-oriented extension to Common LISP (Flavors). Invisible connections for flow compatibility, control connections, iterative propagation, and embedded propagation were among the features provided for derivation of causal ordering. Deterministic output was guaranteed

Jack C. Schryver

1992-01-01

443

Dynamic simulation model for hybrid electric scooters  

Microsoft Academic Search

This paper presents a dynamic simulation model for a hybrid electric scooter (HES) designed by NPUST in Taiwan. The HES is built in a parallel hybrid configuration with a 24 V 370 W auxiliary power electric motor, a 24 V 600 W generator, a 24 V 15 AH battery, and an electronically controlled fuel injection internal combustion engine (ICE). Because

Chyuan-Yow Tseng; Yeou-Feng Lue; Yuan-Ting Lirr; Jheng-Cin Siao; Chien-Hsiung Tsai; Lung-Ming Fu

2009-01-01

444

Love Kills:. Simulations in Penna Ageing Model  

NASA Astrophysics Data System (ADS)

The standard Penna ageing model with sexual reproduction is enlarged by adding additional bit-strings for love: Marriage happens only if the male love strings are sufficiently different from the female ones. We simulate at what level of required difference the population dies out.

Stauffer, Dietrich; Cebrat, Stanis?aw; Penna, T. J. P.; Sousa, A. O.

445

Modeling and simulation of bubbles and particles  

Microsoft Academic Search

The interaction of particles, drops, and bubbles with a fluid (gas or liquid) is important in a number of engineering problems. The present works seeks to extend the understanding of these interactions through numerical simulation. To model many of these relevant flows, it is often important to consider finite Reynolds number effects on drag, lift, torque and history force. Thus,

Andrew James Dorgan

2009-01-01

446

Theory, Modeling and Simulation Annual Report 2000  

Microsoft Academic Search

This annual report describes the 2000 research accomplishments for the Theory, Modeling, and Simulation (TM&S) directorate, one of the six research organizations in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). EMSL is a U.S. Department of Energy (DOE) national scientific user facility and is the centerpiece of the DOE commitment to providing

David A. Dixon; Bruce C. Garrett; Tp Straatsma; Donald R. Jones; Ronald S. Studham; Robert J. Harrison; Jeffrey A. Nichols

2001-01-01

447

Theory, Modeling and Simulation Annual Report 2000  

Microsoft Academic Search

This annual report describes the 2000 research accomplishments for the Theory, Modeling, and Simulation (TM and S) directorate, one of the six research organizations in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). EMSL is a U.S. Department of Energy (DOE) national scientific user facility and is the centerpiece of the DOE commitment

David A Dixon; Bruce C Garrett; TP Straatsma; Donald R Jones; Scott Studham; Robert J Harrison; Jeffrey A Nichols

2001-01-01

448

Adaptive Modeling and Real-Time Simulation.  

National Technical Information Service (NTIS)

This is the final report covering progress on a two year research effort towards the development of basic technology for adaptive modeling and real-time computer simulation to support decision-making in a number of critical planning situations that arise ...

W. M. Tyson

1984-01-01

449

WATER SUPPLY SIMULATION MODEL. VOLUME 3. DOCUMENTATION  

EPA Science Inventory

This three-volume report describes the development of a water supply simulation model (WSSM), a system of computer programs that allows for a systematic evaluation of the physical and economic characteristics of a water distribution system in a spatial framework. The WSSM concept...

450

Dynamics modeling and simulation of flexible airships  

Microsoft Academic Search

The resurgence of airships has created a need for dynamics models and simulation capabilities of these lighter-than-air vehicles. The focus of this thesis is a theoretical framework that integrates the flight dynamics, structural dynamics, aerostatics and aerodynamics of flexible airships. The study begins with a dynamics model based on a rigid-body assumption. A comprehensive computation of aerodynamic effects is presented,

Yuwen Li

2008-01-01

451

Thermohydraulic modeling and simulation of breeder reactors  

SciTech Connect

This paper deals with the modeling and simulation of system-wide transients in LMFBRs. Unprotected events (i.e., the presumption of failure of the plant protection system) leading to core-melt are not considered in this paper. The existing computational capabilities in the area of protected transients in the US are noted. Various physical and numerical approximations that are made in these codes are discussed. Finally, the future direction in the area of model verification and improvements is discussed.

Agrawal, A.K.; Khatib-Rahbar, M.; Curtis, R.T.; Hetrick, D.L.; Girijashankar, P.V.

1982-01-01

452

Modeling and simulation of 12.5 Gb\\/s on a HyperBGA® package  

Microsoft Academic Search

This paper presents high-speed\\/high-frequency modeling and simulation results for Endicott Interconnect Technologies' HyperBGA® organic chip-carrier package. Utilizing industry leading advanced software tools, Ansoft LinksTM, Ansoft HFSSTM, and Ansoft Serenade®, this modeling and simulation effort has demonstrated that current HyperBGA® technology will meet the performance requirements for applications running at speeds of 12.5 Gb\\/s per channel. Throughout the course of this

Ryan D. McBride; Steven G. Rosser; Ronald P. Nowak

2003-01-01

453

Conceptual Model Development for C4ISR Simulations  

Microsoft Academic Search

A simulation conceptual model is the simulation developer's way of translating modeling requirements (i. e., what is to be represented by the simulation) into a detailed design framework (i. e., how it is to be done), from which the software, hardware, networks (in the case of distributed simulation), and systems\\/equipment that will make up the simulation can be built. Standards

Dale K. Pace

454

Modelling and simulation of intelligent multimedia communication networks  

NASA Astrophysics Data System (ADS)

Techniques and features that have been found useful for modeling and simulating intelligent multimedia communications networks are described. Key ingredients are a robust, commercially available and supported simulation language and a modeling and simulation architecture that consists of custom-designed modules of the features that clearly occur in communication network