Solar Potential Analysis and Integration of the Time-Dependent Simulation Results for Semantic 3d City Models Using Dynamizers

Science.gov (United States)

Chaturvedi, K.; Willenborg, B.; Sindram, M.; Kolbe, T. H.

2017-10-01

Semantic 3D city models play an important role in solving complex real-world problems and are being adopted by many cities around the world. A wide range of application and simulation scenarios directly benefit from the adoption of international standards such as CityGML. However, most of the simulations involve properties, whose values vary with respect to time, and the current generation semantic 3D city models do not support time-dependent properties explicitly. In this paper, the details of solar potential simulations are provided operating on the CityGML standard, assessing and estimating solar energy production for the roofs and facades of the 3D building objects in different ways. Furthermore, the paper demonstrates how the time-dependent simulation results are better-represented inline within 3D city models utilizing the so-called Dynamizer concept. This concept not only allows representing the simulation results in standardized ways, but also delivers a method to enhance static city models by such dynamic property values making the city models truly dynamic. The dynamizer concept has been implemented as an Application Domain Extension of the CityGML standard within the OGC Future City Pilot Phase 1. The results are given in this paper.

Electron-cloud simulation results for the SPS and recent results for the LHC

International Nuclear Information System (INIS)

Furman, M.A.; Pivi, M.T.F.

2002-01-01

We present an update of computer simulation results for some features of the electron cloud at the Large Hadron Collider (LHC) and recent simulation results for the Super Proton Synchrotron (SPS). We focus on the sensitivity of the power deposition on the LHC beam screen to the emitted electron spectrum, which we study by means of a refined secondary electron (SE) emission model recently included in our simulation code

Linear regression metamodeling as a tool to summarize and present simulation model results.

Science.gov (United States)

Jalal, Hawre; Dowd, Bryan; Sainfort, François; Kuntz, Karen M

2013-10-01

Modelers lack a tool to systematically and clearly present complex model results, including those from sensitivity analyses. The objective was to propose linear regression metamodeling as a tool to increase transparency of decision analytic models and better communicate their results. We used a simplified cancer cure model to demonstrate our approach. The model computed the lifetime cost and benefit of 3 treatment options for cancer patients. We simulated 10,000 cohorts in a probabilistic sensitivity analysis (PSA) and regressed the model outcomes on the standardized input parameter values in a set of regression analyses. We used the regression coefficients to describe measures of sensitivity analyses, including threshold and parameter sensitivity analyses. We also compared the results of the PSA to deterministic full-factorial and one-factor-at-a-time designs. The regression intercept represented the estimated base-case outcome, and the other coefficients described the relative parameter uncertainty in the model. We defined simple relationships that compute the average and incremental net benefit of each intervention. Metamodeling produced outputs similar to traditional deterministic 1-way or 2-way sensitivity analyses but was more reliable since it used all parameter values. Linear regression metamodeling is a simple, yet powerful, tool that can assist modelers in communicating model characteristics and sensitivity analyses.

Verification of simulation model with COBRA-IIIP code by confrontment of experimental results

International Nuclear Information System (INIS)

Silva Galetti, M.R. da; Pontedeiro, A.C.; Oliveira Barroso, A.C. de

1985-01-01

It is presented an evaluation of the COBRA IIIP/MIT code (of thermal hydraulic analysis by subchannels), comparing their results with experimental data obtained in stationary and transient regimes. It was done a study to calculate the spatial and temporal critical heat flux. It is presented a sensitivity study of simulation model related to the turbulent mixture and the number of axial intervals. (M.C.K.) [pt

Large-scale Validation of AMIP II Land-surface Simulations: Preliminary Results for Ten Models

Energy Technology Data Exchange (ETDEWEB)

Phillips, T J; Henderson-Sellers, A; Irannejad, P; McGuffie, K; Zhang, H

2005-12-01

This report summarizes initial findings of a large-scale validation of the land-surface simulations of ten atmospheric general circulation models that are entries in phase II of the Atmospheric Model Intercomparison Project (AMIP II). This validation is conducted by AMIP Diagnostic Subproject 12 on Land-surface Processes and Parameterizations, which is focusing on putative relationships between the continental climate simulations and the associated models' land-surface schemes. The selected models typify the diversity of representations of land-surface climate that are currently implemented by the global modeling community. The current dearth of global-scale terrestrial observations makes exacting validation of AMIP II continental simulations impractical. Thus, selected land-surface processes of the models are compared with several alternative validation data sets, which include merged in-situ/satellite products, climate reanalyses, and off-line simulations of land-surface schemes that are driven by observed forcings. The aggregated spatio-temporal differences between each simulated process and a chosen reference data set then are quantified by means of root-mean-square error statistics; the differences among alternative validation data sets are similarly quantified as an estimate of the current observational uncertainty in the selected land-surface process. Examples of these metrics are displayed for land-surface air temperature, precipitation, and the latent and sensible heat fluxes. It is found that the simulations of surface air temperature, when aggregated over all land and seasons, agree most closely with the chosen reference data, while the simulations of precipitation agree least. In the latter case, there also is considerable inter-model scatter in the error statistics, with the reanalyses estimates of precipitation resembling the AMIP II simulations more than to the chosen reference data. In aggregate, the simulations of land-surface latent and

Computational fluid dynamics simulations and validations of results

CSIR Research Space (South Africa)

Sitek, MA

2013-09-01

Full Text Available Wind flow influence on a high-rise building is analyzed. The research covers full-scale tests, wind-tunnel experiments and numerical simulations. In the present paper computational model used in simulations is described and the results, which were...

Thermal unit availability modeling in a regional simulation model

International Nuclear Information System (INIS)

Yamayee, Z.A.; Port, J.; Robinett, W.

1983-01-01

The System Analysis Model (SAM) developed under the umbrella of PNUCC's System Analysis Committee is capable of simulating the operation of a given load/resource scenario. This model employs a Monte-Carlo simulation to incorporate uncertainties. Among uncertainties modeled is thermal unit availability both for energy simulation (seasonal) and capacity simulations (hourly). This paper presents the availability modeling in the capacity and energy models. The use of regional and national data in deriving the two availability models, the interaction between the two and modifications made to the capacity model in order to reflect regional practices is presented. A sample problem is presented to show the modification process. Results for modeling a nuclear unit using NERC-GADS is presented

Whole-building Hygrothermal Simulation Model

DEFF Research Database (Denmark)

Rode, Carsten; Grau, Karl

2003-01-01

An existing integrated simulation tool for dynamic thermal simulation of building was extended with a transient model for moisture release and uptake in building materials. Validation of the new model was begun with comparison against measurements in an outdoor test cell furnished with single...... materials. Almost quasi-steady, cyclic experiments were used to compare the indoor humidity variation and the numerical results of the integrated simulation tool with the new moisture model. Except for the case with chipboard as furnishing, the predictions of indoor humidity with the detailed model were...

Pedestrian simulation model based on principles of bounded rationality: results of validation tests

NARCIS (Netherlands)

Zhu, W.; Timmermans, H.J.P.; Lo, H.P.; Leung, Stephen C.H.; Tan, Susanna M.L.

2009-01-01

Over the years, different modelling approaches to simulating pedestrian movement have been suggested. The majority of pedestrian decision models are based on the concept of utility maximization. To explore alternatives, we developed the heterogeneous heuristic model (HHM), based on principles of

Impact of Assimilation on Heavy Rainfall Simulations Using WRF Model: Sensitivity of Assimilation Results to Background Error Statistics

Science.gov (United States)

Rakesh, V.; Kantharao, B.

2017-03-01

Data assimilation is considered as one of the effective tools for improving forecast skill of mesoscale models. However, for optimum utilization and effective assimilation of observations, many factors need to be taken into account while designing data assimilation methodology. One of the critical components that determines the amount and propagation observation information into the analysis, is model background error statistics (BES). The objective of this study is to quantify how BES in data assimilation impacts on simulation of heavy rainfall events over a southern state in India, Karnataka. Simulations of 40 heavy rainfall events were carried out using Weather Research and Forecasting Model with and without data assimilation. The assimilation experiments were conducted using global and regional BES while the experiment with no assimilation was used as the baseline for assessing the impact of data assimilation. The simulated rainfall is verified against high-resolution rain-gage observations over Karnataka. Statistical evaluation using several accuracy and skill measures shows that data assimilation has improved the heavy rainfall simulation. Our results showed that the experiment using regional BES outperformed the one which used global BES. Critical thermo-dynamic variables conducive for heavy rainfall like convective available potential energy simulated using regional BES is more realistic compared to global BES. It is pointed out that these results have important practical implications in design of forecast platforms while decision-making during extreme weather events

A hierarchy of models for simulating experimental results from a 3D heterogeneous porous medium

Science.gov (United States)

Vogler, Daniel; Ostvar, Sassan; Paustian, Rebecca; Wood, Brian D.

2018-04-01

In this work we examine the dispersion of conservative tracers (bromide and fluorescein) in an experimentally-constructed three-dimensional dual-porosity porous medium. The medium is highly heterogeneous (σY2 = 5.7), and consists of spherical, low-hydraulic-conductivity inclusions embedded in a high-hydraulic-conductivity matrix. The bimodal medium was saturated with tracers, and then flushed with tracer-free fluid while the effluent breakthrough curves were measured. The focus for this work is to examine a hierarchy of four models (in the absence of adjustable parameters) with decreasing complexity to assess their ability to accurately represent the measured breakthrough curves. The most information-rich model was (1) a direct numerical simulation of the system in which the geometry, boundary and initial conditions, and medium properties were fully independently characterized experimentally with high fidelity. The reduced-information models included; (2) a simplified numerical model identical to the fully-resolved direct numerical simulation (DNS) model, but using a domain that was one-tenth the size; (3) an upscaled mobile-immobile model that allowed for a time-dependent mass-transfer coefficient; and, (4) an upscaled mobile-immobile model that assumed a space-time constant mass-transfer coefficient. The results illustrated that all four models provided accurate representations of the experimental breakthrough curves as measured by global RMS error. The primary component of error induced in the upscaled models appeared to arise from the neglect of convection within the inclusions. We discuss the necessity to assign value (via a utility function or other similar method) to outcomes if one is to further select from among model options. Interestingly, these results suggested that the conventional convection-dispersion equation, when applied in a way that resolves the heterogeneities, yields models with high fidelity without requiring the imposition of a more

Assessment of effectiveness of geologic isolation systems. Geologic-simulation model for a hypothetical site in the Columbia Plateau. Volume 2: results

International Nuclear Information System (INIS)

Foley, M.G.; Petrie, G.M.; Baldwin, A.J.; Craig, R.G.

1982-06-01

This report contains the input data and computer results for the Geologic Simulation Model. This model is described in detail in the following report: Petrie, G.M., et. al. 1981. Geologic Simulation Model for a Hypothetical Site in the Columbia Plateau, Pacific Northwest Laboratory, Richland, Washington. The Geologic Simulation Model is a quasi-deterministic process-response model which simulates, for a million years into the future, the development of the geologic and hydrologic systems of the ground-water basin containing the Pasco Basin. Effects of natural processes on the ground-water hydrologic system are modeled principally by rate equations. The combined effects and synergistic interactions of different processes are approximated by linear superposition of their effects during discrete time intervals in a stepwise-integration approach

Assessment of effectiveness of geologic isolation systems. Geologic-simulation model for a hypothetical site in the Columbia Plateau. Volume 2: results

Energy Technology Data Exchange (ETDEWEB)

Foley, M.G.; Petrie, G.M.; Baldwin, A.J.; Craig, R.G.

1982-06-01

This report contains the input data and computer results for the Geologic Simulation Model. This model is described in detail in the following report: Petrie, G.M., et. al. 1981. Geologic Simulation Model for a Hypothetical Site in the Columbia Plateau, Pacific Northwest Laboratory, Richland, Washington. The Geologic Simulation Model is a quasi-deterministic process-response model which simulates, for a million years into the future, the development of the geologic and hydrologic systems of the ground-water basin containing the Pasco Basin. Effects of natural processes on the ground-water hydrologic system are modeled principally by rate equations. The combined effects and synergistic interactions of different processes are approximated by linear superposition of their effects during discrete time intervals in a stepwise-integration approach.

Control of Warm Compression Stations Using Model Predictive Control: Simulation and Experimental Results

Science.gov (United States)

Bonne, F.; Alamir, M.; Bonnay, P.

2017-02-01

This paper deals with multivariable constrained model predictive control for Warm Compression Stations (WCS). WCSs are subject to numerous constraints (limits on pressures, actuators) that need to be satisfied using appropriate algorithms. The strategy is to replace all the PID loops controlling the WCS with an optimally designed model-based multivariable loop. This new strategy leads to high stability and fast disturbance rejection such as those induced by a turbine or a compressor stop, a key-aspect in the case of large scale cryogenic refrigeration. The proposed control scheme can be used to achieve precise control of pressures in normal operation or to avoid reaching stopping criteria (such as excessive pressures) under high disturbances (such as a pulsed heat load expected to take place in future fusion reactors, expected in the cryogenic cooling systems of the International Thermonuclear Experimental Reactor ITER or the Japan Torus-60 Super Advanced fusion experiment JT-60SA). The paper details the simulator used to validate this new control scheme and the associated simulation results on the SBTs WCS. This work is partially supported through the French National Research Agency (ANR), task agreement ANR-13-SEED-0005.

SEIR model simulation for Hepatitis B

Science.gov (United States)

Side, Syafruddin; Irwan, Mulbar, Usman; Sanusi, Wahidah

2017-09-01

Mathematical modelling and simulation for Hepatitis B discuss in this paper. Population devided by four variables, namely: Susceptible, Exposed, Infected and Recovered (SEIR). Several factors affect the population in this model is vaccination, immigration and emigration that occurred in the population. SEIR Model obtained Ordinary Differential Equation (ODE) non-linear System 4-D which then reduces to 3-D. SEIR model simulation undertaken to predict the number of Hepatitis B cases. The results of the simulation indicates the number of Hepatitis B cases will increase and then decrease for several months. The result of simulation using the number of case in Makassar also found the basic reproduction number less than one, that means, Makassar city is not an endemic area of Hepatitis B.

Advances in Intelligent Modelling and Simulation Simulation Tools and Applications

CERN Document Server

Oplatková, Zuzana; Carvalho, Marco; Kisiel-Dorohinicki, Marek

2012-01-01

The human capacity to abstract complex systems and phenomena into simplified models has played a critical role in the rapid evolution of our modern industrial processes and scientific research. As a science and an art, Modelling and Simulation have been one of the core enablers of this remarkable human trace, and have become a topic of great importance for researchers and practitioners. This book was created to compile some of the most recent concepts, advances, challenges and ideas associated with Intelligent Modelling and Simulation frameworks, tools and applications. The first chapter discusses the important aspects of a human interaction and the correct interpretation of results during simulations. The second chapter gets to the heart of the analysis of entrepreneurship by means of agent-based modelling and simulations. The following three chapters bring together the central theme of simulation frameworks, first describing an agent-based simulation framework, then a simulator for electrical machines, and...

Hamiltonian and potentials in derivative pricing models: exact results and lattice simulations

Science.gov (United States)

Baaquie, Belal E.; Corianò, Claudio; Srikant, Marakani

2004-03-01

The pricing of options, warrants and other derivative securities is one of the great success of financial economics. These financial products can be modeled and simulated using quantum mechanical instruments based on a Hamiltonian formulation. We show here some applications of these methods for various potentials, which we have simulated via lattice Langevin and Monte Carlo algorithms, to the pricing of options. We focus on barrier or path dependent options, showing in some detail the computational strategies involved.

Sensitivity analysis for thermo-hydraulics model of a Westinghouse type PWR. Verification of the simulation results

Energy Technology Data Exchange (ETDEWEB)

Farahani, Aref Zarnooshe [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Nuclear Engineering, Science and Research Branch; Yousefpour, Faramarz [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Hoseyni, Seyed Mohsen [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Basic Sciences; Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Young Researchers and Elite Club

2017-07-15

Development of a steady-state model is the first step in nuclear safety analysis. The developed model should be qualitatively analyzed first, then a sensitivity analysis is required on the number of nodes for models of different systems to ensure the reliability of the obtained results. This contribution aims to show through sensitivity analysis, the independence of modeling results to the number of nodes in a qualified MELCOR model for a Westinghouse type pressurized power plant. For this purpose, and to minimize user error, the nuclear analysis software, SNAP, is employed. Different sensitivity cases were developed by modification of the existing model and refinement of the nodes for the simulated systems including steam generators, reactor coolant system and also reactor core and its connecting flow paths. By comparing the obtained results to those of the original model no significant difference is observed which is indicative of the model independence to the finer nodes.

Experiment vs simulation RT WFNDEC 2014 benchmark: CIVA results

International Nuclear Information System (INIS)

Tisseur, D.; Costin, M.; Rattoni, B.; Vienne, C.; Vabre, A.; Cattiaux, G.; Sollier, T.

2015-01-01

The French Atomic Energy Commission and Alternative Energies (CEA) has developed for years the CIVA software dedicated to simulation of NDE techniques such as Radiographic Testing (RT). RT modelling is achieved in CIVA using combination of a determinist approach based on ray tracing for transmission beam simulation and a Monte Carlo model for the scattered beam computation. Furthermore, CIVA includes various detectors models, in particular common x-ray films and a photostimulable phosphor plates. This communication presents the results obtained with the configurations proposed in the World Federation of NDEC 2014 RT modelling benchmark with the RT models implemented in the CIVA software

Experiment vs simulation RT WFNDEC 2014 benchmark: CIVA results

Energy Technology Data Exchange (ETDEWEB)

Tisseur, D., E-mail: david.tisseur@cea.fr; Costin, M., E-mail: david.tisseur@cea.fr; Rattoni, B., E-mail: david.tisseur@cea.fr; Vienne, C., E-mail: david.tisseur@cea.fr; Vabre, A., E-mail: david.tisseur@cea.fr; Cattiaux, G., E-mail: david.tisseur@cea.fr [CEA LIST, CEA Saclay 91191 Gif sur Yvette Cedex (France); Sollier, T. [Institut de Radioprotection et de Sûreté Nucléaire, B.P.17 92262 Fontenay-Aux-Roses (France)

2015-03-31

The French Atomic Energy Commission and Alternative Energies (CEA) has developed for years the CIVA software dedicated to simulation of NDE techniques such as Radiographic Testing (RT). RT modelling is achieved in CIVA using combination of a determinist approach based on ray tracing for transmission beam simulation and a Monte Carlo model for the scattered beam computation. Furthermore, CIVA includes various detectors models, in particular common x-ray films and a photostimulable phosphor plates. This communication presents the results obtained with the configurations proposed in the World Federation of NDEC 2014 RT modelling benchmark with the RT models implemented in the CIVA software.

Modelling and Simulation of Wave Loads

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard; Thoft-Christensen, Palle

velocity can be approximated by a Gaussian Markov process. Known approximate results for the first-passage density or equivalently, the distribution of the extremes of wave loads are presented and compared with rather precise simulation results. It is demonstrated that the approximate results......A simple model of the wave load on slender members of offshore structures is described. The wave elevation of the sea state is modelled by a stationary Gaussian process. A new procedure to simulate realizations of the wave loads is developed. The simulation method assumes that the wave particle...

Modelling and Simulation of Wave Loads

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard; Thoft-Christensen, Palle

1985-01-01

velocity can be approximated by a Gaussian Markov process. Known approximate results for the first passage density or equivalently, the distribution of the extremes of wave loads are presented and compared with rather precise simulation results. It is demonstrated that the approximate results......A simple model of the wave load on stender members of offshore structures is described . The wave elevation of the sea stateis modelled by a stationary Gaussian process. A new procedure to simulate realizations of the wave loads is developed. The simulation method assumes that the wave particle...

ANOVA parameters influence in LCF experimental data and simulation results

Directory of Open Access Journals (Sweden)

Vercelli A.

2010-06-01

Full Text Available The virtual design of components undergoing thermo mechanical fatigue (TMF and plastic strains is usually run in many phases. The numerical finite element method gives a useful instrument which becomes increasingly effective as the geometrical and numerical modelling gets more accurate. The constitutive model definition plays an important role in the effectiveness of the numerical simulation [1, 2] as, for example, shown in Figure 1. In this picture it is shown how a good cyclic plasticity constitutive model can simulate a cyclic load experiment. The component life estimation is the subsequent phase and it needs complex damage and life estimation models [3-5] which take into account of several parameters and phenomena contributing to damage and life duration. The calibration of these constitutive and damage models requires an accurate testing activity. In the present paper the main topic of the research activity is to investigate whether the parameters, which result to be influent in the experimental activity, influence the numerical simulations, thus defining the effectiveness of the models in taking into account of all the phenomena actually influencing the life of the component. To obtain this aim a procedure to tune the parameters needed to estimate the life of mechanical components undergoing TMF and plastic strains is presented for commercial steel. This procedure aims to be easy and to allow calibrating both material constitutive model (for the numerical structural simulation and the damage and life model (for life assessment. The procedure has been applied to specimens. The experimental activity has been developed on three sets of tests run at several temperatures: static tests, high cycle fatigue (HCF tests, low cycle fatigue (LCF tests. The numerical structural FEM simulations have been run on a commercial non linear solver, ABAQUS®6.8. The simulations replied the experimental tests. The stress, strain, thermal results from the thermo

THE MARK I BUSINESS SYSTEM SIMULATION MODEL

Science.gov (United States)

of a large-scale business simulation model as a vehicle for doing research in management controls. The major results of the program were the...development of the Mark I business simulation model and the Simulation Package (SIMPAC). SIMPAC is a method and set of programs facilitating the construction...of large simulation models. The object of this document is to describe the Mark I Corporation model, state why parts of the business were modeled as they were, and indicate the research applications of the model. (Author)

Challenges of forest landscape modeling - simulating large landscapes and validating results

Science.gov (United States)

Hong S. He; Jian Yang; Stephen R. Shifley; Frank R. Thompson

2011-01-01

Over the last 20 years, we have seen a rapid development in the field of forest landscape modeling, fueled by both technological and theoretical advances. Two fundamental challenges have persisted since the inception of FLMs: (1) balancing realistic simulation of ecological processes at broad spatial and temporal scales with computing capacity, and (2) validating...

Results from a 2 x CO2 simulation with the Canadian Climate Centre general circulation model

International Nuclear Information System (INIS)

Boer, G.J.

1990-01-01

The Canadian Climate Centre's general circulation model (GCM), GCMII, was used to simulate a doubling of atmospheric carbon dioxide concentration. The experiment was a standard greenhouse gas climate change study, using a three-dimensional atmospheric circulation model coupled to a simple 'slab' ocean and a thermodynamic ice model. This standard experiment retains the sophistication and generality of an atmospheric GCM, is straightforward in its use of simplified ocean and ice models, is comparatively economical of computer time, and permits comparison of results from different models. Features of the second generation GCMII include: higher resolution at T32L10 with a transform grid of 3.75 x 3.75 degree; full diurnal and annual cycles; ocean and sea ice treatment involving specification of ocean transports; modified treatment of land surface processes and hydrology; a parameterization of cloud optical feedback; and a retention of the special application data sets of surface parameters for North America and Europe. Results of the simulation were a globally averaged surface temperature increase of 3.5 degree C; a precipitation and evaporation increase of 3%; an average decrease in soil moisture of 6.6%; a decrease in cloud cover of 2.2%; a 66% decrease in mass of sea ice; and marked changes in other quantities in the polar region. 2 refs., 2 figs., 2 tabs

Modeling results for a linear simulator of a divertor

International Nuclear Information System (INIS)

Hooper, E.B.; Brown, M.D.; Byers, J.A.; Casper, T.A.; Cohen, B.I.; Cohen, R.H.; Jackson, M.C.; Kaiser, T.B.; Molvik, A.W.; Nevins, W.M.; Nilson, D.G.; Pearlstein, L.D.; Rognlien, T.D.

1993-01-01

A divertor simulator, IDEAL, has been proposed by S. Cohen to study the difficult power-handling requirements of the tokamak program in general and the ITER program in particular. Projections of the power density in the ITER divertor reach ∼ 1 Gw/m 2 along the magnetic fieldlines and > 10 MW/m 2 on a surface inclined at a shallow angle to the fieldlines. These power densities are substantially greater than can be handled reliably on the surface, so new techniques are required to reduce the power density to a reasonable level. Although the divertor physics must be demonstrated in tokamaks, a linear device could contribute to the development because of its flexibility, the easy access to the plasma and to tested components, and long pulse operation (essentially cw). However, a decision to build a simulator requires not just the recognition of its programmatic value, but also confidence that it can meet the required parameters at an affordable cost. Accordingly, as reported here, it was decided to examine the physics of the proposed device, including kinetic effects resulting from the intense heating required to reach the plasma parameters, and to conduct an independent cost estimate. The detailed role of the simulator in a divertor program is not explored in this report

Electron-cloud simulation results for the PSR and SNS

International Nuclear Information System (INIS)

Pivi, M.; Furman, M.A.

2002-01-01

We present recent simulation results for the main features of the electron cloud in the storage ring of the Spallation Neutron Source (SNS) at Oak Ridge, and updated results for the Proton Storage Ring (PSR) at Los Alamos. In particular, a complete refined model for the secondary emission process including the so called true secondary, rediffused and backscattered electrons has been included in the simulation code

Progress in modeling and simulation.

Science.gov (United States)

Kindler, E

1998-01-01

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.

Streamflow in the upper Mississippi river basin as simulated by SWAT driven by 20{sup th} century contemporary results of global climate models and NARCCAP regional climate models

Energy Technology Data Exchange (ETDEWEB)

Takle, Eugene S.; Jha, Manoj; Lu, Er; Arritt, Raymond W.; Gutowski, William J. [Iowa State Univ. Ames, IA (United States)

2010-06-15

We use Soil and Water Assessment Tool (SWAT) when driven by observations and results of climate models to evaluate hydrological quantities, including streamflow, in the Upper Mississippi River Basin (UMRB) for 1981-2003 in comparison to observed streamflow. Daily meteorological conditions used as input to SWAT are taken from (1) observations at weather stations in the basin, (2) daily meteorological conditions simulated by a collection of regional climate models (RCMs) driven by reanalysis boundary conditions, and (3) daily meteorological conditions simulated by a collection of global climate models (GCMs). Regional models used are those whose data are archived by the North American Regional Climate Change Assessment Program (NARCCAP). Results show that regional models correctly simulate the seasonal cycle of precipitation, temperature, and streamflow within the basin. Regional models also capture interannual extremes represented by the flood of 1993 and the dry conditions of 2000. The ensemble means of both the GCM-driven and RCM-driven simulations by SWAT capture both the timing and amplitude of the seasonal cycle of streamflow with neither demonstrating significant superiority at the basin level. (orig.)

A comparison study between observations and simulation results of Barghouthi model for O+ and H+ outflows in the polar wind

Directory of Open Access Journals (Sweden)

I. A. Barghouthi

2011-11-01

Full Text Available To advance our understanding of the effect of wave-particle interactions on ion outflows in the polar wind region and the resulting ion heating and escape from low altitudes to higher altitudes, we carried out a comparison between polar wind simulations obtained using Barghouthi model with corresponding observations obtained from different satellites. The Barghouthi model describes O+ and H+ outflows in the polar wind region in the range 1.7 RE to 13.7 RE, including the effects of gravity, polarization electrostatic field, diverging geomagnetic field lines, and wave-particle interactions. Wave-particle interactions were included into the model by using a particle diffusion equation, which depends on diffusion coefficients determined from estimates of the typical electric field spectral density at relevant altitudes and frequencies. We provide a formula for the velocity diffusion coefficient that depends on altitude and velocity, in which the velocity part depends on the perpendicular wavelength of the electromagnetic turbulence λ⊥. Because of the shortage of information about λ⊥, it was included into the model as a parameter. We produce different simulations (i.e. ion velocity distributions, ions density, ion drift velocity, ion parallel and perpendicular temperatures for O+ and H+ ions, and for different λ⊥. We discuss the simulations in terms of wave-particle interactions, perpendicular adiabatic cooling, parallel adiabatic cooling, mirror force, and ion potential energy. The main findings of the simulations are as follows: (1 O+ ions are highly energized at all altitudes in the simulation tube due to wave-particle interactions that heat the ions in the perpendicular direction, and part of this gained energy transfer to the parallel direction by mirror force, resulting in accelerating O+ ions along geomagnetic field lines from lower altitudes to higher altitudes. (2 The effect of wave-particle interactions is negligible for H

The Titan Haze Simulation Experiment: Latest Laboratory Results and Dedicated Plasma Chemistry Model

Science.gov (United States)

Sciamma-O'Brien, Ella; Raymond, Alexander; Mazur, Eric; Salama, Farid

2018-06-01

Here, we present the latest results on the gas and solid phase analyses in the Titan Haze Simulation (THS) experiment. The THS experiment, developed at NASA Ames’ COSmIC facility is a unique experimental platform that allows us to simulate Titan’s complex atmospheric chemistry at Titan-like temperature (200 K) by cooling down N2-CH4-based mixtures in a supersonic expansion before inducing the chemistry by plasma.Gas phase: The residence time of the jet-accelerated gas in the active plasma region is less than 4 µs, which results in a truncated chemistry enabling us to control how far in the chain of reactions the chemistry is processing. By adding heavier molecules in the initial gas mixture, it is then possible to study the first and intermediate steps of Titan’s atmospheric chemistry as well as specific chemical pathways, as demonstrated by mass spectrometry and comparison to Cassini CAPS data [1]. A new model was recently developed to simulate the plasma chemistry in the THS. Calculated mass spectra produced by this model are in good agreement with the experimental THS mass spectra, confirming that the short residence time in the plasma cavity limits the growth of larger species [2].Solid phase: Scanning electron microscopy and infrared spectroscopy have been used to investigate the effect of the initial gas mixture on the morphology of the THS Titan aerosol analogs as well as on the level and nature of the nitrogen incorporation into these aerosols. A comparison to Cassini VIMS observational data has shown that the THS aerosols produced in simpler mixtures, i.e., that contain more nitrogen and where the N-incorporation is in isocyanide-type molecules instead of nitriles, are more representative of Titan’s aerosols [3]. In addition, a new optical constant facility has been developed at NASA Ames that allows us to determine the complex refractive indices of THS Titan aerosol analogs from NIR to FIR (0.76-222 cm-1). The facility and preliminary results

Impact of Transport Zone Number in Simulation Models on Cost-Benefit Analysis Results in Transport Investments

Science.gov (United States)

Chmielewski, Jacek

2017-10-01

Nowadays, feasibility studies need to be prepared for all planned transport investments, mainly those co-financed with UE grants. One of the fundamental aspect of feasibility study is the economic justification of an investment, evaluated in an area of so called cost-benefit analysis (CBA). The main goal of CBA calculation is to prove that a transport investment is really important for the society and should be implemented as economically efficient one. It can be said that the number of hours (PH - passengers hours) in trips and travelled kilometres (PK - passengers kilometres) are the most important for CBA results. The differences between PH and PK calculated for particular investment scenarios are the base for benefits calculation. Typically, transport simulation models are the best source for such data. Transport simulation models are one of the most powerful tools for transport network planning. They make it possible to evaluate forecast traffic volume and passenger flows in a public transport system for defined scenarios of transport and area development. There are many different transport models. Their construction is often similar, and they mainly differ in the level of their accuracy. Even models for the same area may differ in this matter. Typically, such differences come from the accuracy of supply side representation: road and public transport network representation. In many cases only main roads and a public transport network are represented, while local and service roads are eliminated as a way of reality simplification. This also enables a faster and more effective calculation process. On the other hand, the description of demand part of these models based on transport zones is often stable. Difficulties with data collection, mainly data on land use, resulted in the lack of changes in the analysed land division into so called transport zones. In this paper the author presents an influence of land division on the results of traffic analyses, and hence

COMPARISON OF RF CAVITY TRANSPORT MODELS FOR BBU SIMULATIONS

Energy Technology Data Exchange (ETDEWEB)

Ilkyoung Shin,Byung Yunn,Todd Satogata,Shahid Ahmed

2011-03-01

The transverse focusing effect in RF cavities plays a considerable role in beam dynamics for low-energy beamline sections and can contribute to beam breakup (BBU) instability. The purpose of this analysis is to examine RF cavity models in simulation codes which will be used for BBU experiments at Jefferson Lab and improve BBU simulation results. We review two RF cavity models in the simulation codes elegant and TDBBU (a BBU simulation code developed at Jefferson Lab). elegant can include the Rosenzweig-Serafini (R-S) model for the RF focusing effect. Whereas TDBBU uses a model from the code TRANSPORT which considers the adiabatic damping effect, but not the RF focusing effect. Quantitative comparisons are discussed for the CEBAF beamline. We also compare the R-S model with the results from numerical simulations for a CEBAF-type 5-cell superconducting cavity to validate the use of the R-S model as an improved low-energy RF cavity transport model in TDBBU. We have implemented the R-S model in TDBBU. It will improve BBU simulation results to be more matched with analytic calculations and experimental results.

Comparison Of RF Cavity Transport Models For BBU Simulations

International Nuclear Information System (INIS)

Shin, Ilkyoung; Yunn, Byung; Satogata, Todd; Ahmed, Shahid

2011-01-01

The transverse focusing effect in RF cavities plays a considerable role in beam dynamics for low-energy beamline sections and can contribute to beam breakup (BBU) instability. The purpose of this analysis is to examine RF cavity models in simulation codes which will be used for BBU experiments at Jefferson Lab and improve BBU simulation results. We review two RF cavity models in the simulation codes elegant and TDBBU (a BBU simulation code developed at Jefferson Lab). elegant can include the Rosenzweig-Serafini (R-S) model for the RF focusing effect. Whereas TDBBU uses a model from the code TRANSPORT which considers the adiabatic damping effect, but not the RF focusing effect. Quantitative comparisons are discussed for the CEBAF beamline. We also compare the R-S model with the results from numerical simulations for a CEBAF-type 5-cell superconducting cavity to validate the use of the R-S model as an improved low-energy RF cavity transport model in TDBBU. We have implemented the R-S model in TDBBU. It will improve BBU simulation results to be more matched with analytic calculations and experimental results.

Numerical models: Detailing and simulation techniques aimed at comparison with experimental data, support to test result interpretation

International Nuclear Information System (INIS)

Lin Chiwen

2001-01-01

This part of the presentation discusses the modelling details required and the simulation techniques available for analyses, facilitating the comparison with the experimental data and providing support for interpretation of the test results. It is organised to cover the following topics: analysis inputs; basic modelling requirements for reactor coolant system; method applicable for reactor cooling system; consideration of damping values and integration time steps; typical analytic models used for analysis of reactor pressure vessel and internals; hydrodynamic mass and fluid damping for the internal analysis; impact elements for fuel analysis; and PEI theorem and its applications. The intention of these topics is to identify the key parameters associated with models of analysis and analytical methods. This should provide proper basis for useful comparison with the test results

AEGIS geologic simulation model

International Nuclear Information System (INIS)

Foley, M.G.

1982-01-01

The Geologic Simulation Model (GSM) is used by the AEGIS (Assessment of Effectiveness of Geologic Isolation Systems) program at the Pacific Northwest Laboratory to simulate the dynamic geology and hydrology of a geologic nuclear waste repository site over a million-year period following repository closure. The GSM helps to organize geologic/hydrologic data; to focus attention on active natural processes by requiring their simulation; and, through interactive simulation and calibration, to reduce subjective evaluations of the geologic system. During each computer run, the GSM produces a million-year geologic history that is possible for the region and the repository site. In addition, the GSM records in permanent history files everything that occurred during that time span. Statistical analyses of data in the history files of several hundred simulations are used to classify typical evolutionary paths, to establish the probabilities associated with deviations from the typical paths, and to determine which types of perturbations of the geologic/hydrologic system, if any, are most likely to occur. These simulations will be evaluated by geologists familiar with the repository region to determine validity of the results. Perturbed systems that are determined to be the most realistic, within whatever probability limits are established, will be used for the analyses that involve radionuclide transport and dose models. The GSM is designed to be continuously refined and updated. Simulation models are site specific, and, although the submodels may have limited general applicability, the input data equirements necessitate detailed characterization of each site before application

[Numerical simulation of the effect of virtual stent release pose on the expansion results].

Science.gov (United States)

Li, Jing; Peng, Kun; Cui, Xinyang; Fu, Wenyu; Qiao, Aike

2018-04-01

The current finite element analysis of vascular stent expansion does not take into account the effect of the stent release pose on the expansion results. In this study, stent and vessel model were established by Pro/E. Five kinds of finite element assembly models were constructed by ABAQUS, including 0 degree without eccentricity model, 3 degree without eccentricity model, 5 degree without eccentricity model, 0 degree axial eccentricity model and 0 degree radial eccentricity model. These models were divided into two groups of experiments for numerical simulation with respect to angle and eccentricity. The mechanical parameters such as foreshortening rate, radial recoil rate and dog boning rate were calculated. The influence of angle and eccentricity on the numerical simulation was obtained by comparative analysis. Calculation results showed that the residual stenosis rates were 38.3%, 38.4%, 38.4%, 35.7% and 38.2% respectively for the 5 models. The results indicate that the pose has less effect on the numerical simulation results so that it can be neglected when the accuracy of the result is not highly required, and the basic model as 0 degree without eccentricity model is feasible for numerical simulation.

Structured building model reduction toward parallel simulation

Energy Technology Data Exchange (ETDEWEB)

Dobbs, Justin R. [Cornell University; Hencey, Brondon M. [Cornell University

2013-08-26

Building energy model reduction exchanges accuracy for improved simulation speed by reducing the number of dynamical equations. Parallel computing aims to improve simulation times without loss of accuracy but is poorly utilized by contemporary simulators and is inherently limited by inter-processor communication. This paper bridges these disparate techniques to implement efficient parallel building thermal simulation. We begin with a survey of three structured reduction approaches that compares their performance to a leading unstructured method. We then use structured model reduction to find thermal clusters in the building energy model and allocate processing resources. Experimental results demonstrate faster simulation and low error without any interprocessor communication.

Modeling and simulation of blood collection systems.

Science.gov (United States)

Alfonso, Edgar; Xie, Xiaolan; Augusto, Vincent; Garraud, Olivier

2012-03-01

This paper addresses the modeling and simulation of blood collection systems in France for both fixed site and mobile blood collection with walk in whole blood donors and scheduled plasma and platelet donors. Petri net models are first proposed to precisely describe different blood collection processes, donor behaviors, their material/human resource requirements and relevant regulations. Petri net models are then enriched with quantitative modeling of donor arrivals, donor behaviors, activity times and resource capacity. Relevant performance indicators are defined. The resulting simulation models can be straightforwardly implemented with any simulation language. Numerical experiments are performed to show how the simulation models can be used to select, for different walk in donor arrival patterns, appropriate human resource planning and donor appointment strategies.

Modelling and simulation of a heat exchanger

Science.gov (United States)

Xia, Lei; Deabreu-Garcia, J. Alex; Hartley, Tom T.

1991-01-01

Two models for two different control systems are developed for a parallel heat exchanger. First by spatially lumping a heat exchanger model, a good approximate model which has a high system order is produced. Model reduction techniques are applied to these to obtain low order models that are suitable for dynamic analysis and control design. The simulation method is discussed to ensure a valid simulation result.

EFFECTS OF COOPERATIVE LEARNING MODEL TYPE NUMBERED HEADS TOGETHER USING SIMULATION MEDIA PHET AND ACTIVITIES TOWARD STUDENT RESULTS

Directory of Open Access Journals (Sweden)

Fitri Mawaddah Lubis

2015-12-01

Full Text Available This study aimed to analyze the differences in learning outcomes of students taught by cooperative learning model NHT using simulation PhET and conventional learning, analyzing the differences in learning outcomes of students who have high activity and low activity, as well as the  interaction between learning model with the level of student activity in  influencing the outcome students learn physics. This research is a quasi experimental. The population in this study were students of class X SMK Tritech Informatika Medan. The tests were used to obtain the data is in the form of multiple choice. Test requirements have been carried out in the form of normality and homogeneity, which showed that the normal data and homogeneous. The data were analyzed using Anova analysis of two paths. The results showed that: The physics learning outcomes of students who use cooperative learning model NHT using PhET simulations media is better than students who use conventional learning models. The physics learning outcomes of students who have high learning activities is better than students who have Low learning activities. There is an interaction between cooperative learning model NHT PhET simulations using the media and the level of learning activity in influencing student learning outcomes. Average increase learning outcomes in the control class is greater than the experimental class.

Fusing Simulation Results From Multifidelity Aero-servo-elastic Simulators - Application To Extreme Loads On Wind Turbine

DEFF Research Database (Denmark)

Abdallah, Imad; Sudret, Bruno; Lataniotis, Christos

2015-01-01

Fusing predictions from multiple simulators in the early stages of the conceptual design of a wind turbine results in reduction in model uncertainty and risk mitigation. Aero-servo-elastic is a term that refers to the coupling of wind inflow, aerodynamics, structural dynamics and controls. Fusing...... the response data from multiple aero-servo-elastic simulators could provide better predictive ability than using any single simulator. The co-Kriging approach to fuse information from multifidelity aero-servo-elastic simulators is presented. We illustrate the co-Kriging approach to fuse the extreme flapwise...... bending moment at the blade root of a large wind turbine as a function of wind speed, turbulence and shear exponent in the presence of model uncertainty and non-stationary noise in the output. The extreme responses are obtained by two widely accepted numerical aero-servo-elastic simulators, FAST...

Modeling and simulation of large HVDC systems

Energy Technology Data Exchange (ETDEWEB)

Jin, H.; Sood, V.K.

1993-01-01

This paper addresses the complexity and the amount of work in preparing simulation data and in implementing various converter control schemes and the excessive simulation time involved in modelling and simulation of large HVDC systems. The Power Electronic Circuit Analysis program (PECAN) is used to address these problems and a large HVDC system with two dc links is simulated using PECAN. A benchmark HVDC system is studied to compare the simulation results with those from other packages. The simulation time and results are provided in the paper.

Simulation modeling and arena

CERN Document Server

Rossetti, Manuel D

2015-01-01

Emphasizes a hands-on approach to learning statistical analysis and model building through the use of comprehensive examples, problems sets, and software applications With a unique blend of theory and applications, Simulation Modeling and Arena®, Second Edition integrates coverage of statistical analysis and model building to emphasize the importance of both topics in simulation. Featuring introductory coverage on how simulation works and why it matters, the Second Edition expands coverage on static simulation and the applications of spreadsheets to perform simulation. The new edition als

Modeling and Simulation of U-tube Steam Generator

Science.gov (United States)

Zhang, Mingming; Fu, Zhongguang; Li, Jinyao; Wang, Mingfei

2018-03-01

The U-tube natural circulation steam generator was mainly researched with modeling and simulation in this article. The research is based on simuworks system simulation software platform. By analyzing the structural characteristics and the operating principle of U-tube steam generator, there are 14 control volumes in the model, including primary side, secondary side, down channel and steam plenum, etc. The model depends completely on conservation laws, and it is applied to make some simulation tests. The results show that the model is capable of simulating properly the dynamic response of U-tube steam generator.

Use case driven approach to develop simulation model for PCS of APR1400 simulator

International Nuclear Information System (INIS)

Dong Wook, Kim; Hong Soo, Kim; Hyeon Tae, Kang; Byung Hwan, Bae

2006-01-01

The full-scope simulator is being developed to evaluate specific design feature and to support the iterative design and validation in the Man-Machine Interface System (MMIS) design of Advanced Power Reactor (APR) 1400. The simulator consists of process model, control logic model, and MMI for the APR1400 as well as the Power Control System (PCS). In this paper, a use case driven approach is proposed to develop a simulation model for PCS. In this approach, a system is considered from the point of view of its users. User's view of the system is based on interactions with the system and the resultant responses. In use case driven approach, we initially consider the system as a black box and look at its interactions with the users. From these interactions, use cases of the system are identified. Then the system is modeled using these use cases as functions. Lower levels expand the functionalities of each of these use cases. Hence, starting from the topmost level view of the system, we proceeded down to the lowest level (the internal view of the system). The model of the system thus developed is use case driven. This paper will introduce the functionality of the PCS simulation model, including a requirement analysis based on use case and the validation result of development of PCS model. The PCS simulation model using use case will be first used during the full-scope simulator development for nuclear power plant and will be supplied to Shin-Kori 3 and 4 plant. The use case based simulation model development can be useful for the design and implementation of simulation models. (authors)

Modeling salmonella Dublin into the dairy herd simulation model Simherd

DEFF Research Database (Denmark)

Kudahl, Anne Braad

2010-01-01

Infection with Salmonella Dublin in the dairy herd and effects of the infection and relevant control measures are currently being modeled into the dairy herd simulation model called Simherd. The aim is to compare the effects of different control strategies against Salmonella Dublin on both within...... of the simulations will therefore be used for decision support in the national surveillance and eradication program against Salmonella Dublin. Basic structures of the model are programmed and will be presented at the workshop. The model is in a phase of face-validation by a group of Salmonella......-herd- prevalence and economy by simulations. The project Dublin on both within-herd- prevalence and economy by simulations. The project is a part of a larger national project "Salmonella 2007 - 2011" with the main objective to reduce the prevalence of Salmonella Dublin in Danish Dairy herds. Results...

Model simulation of tide-induced currents in Gauthami-Godavari estuary

Digital Repository Service at National Institute of Oceanography (India)

Sridevi, B.; Murty, T.V.R.; Sadhuram, Y.; Sarma, V.V.S.S.; Naidu, V.S.; Prasad, K.V.S.R.

to achieve model calibration and verification in model simulations of flow field. The model simulation results are in qualitative agreement with the observational data with calibrated bottom roughness length which is about 0.085 m. Model results reveal...

Model improvements to simulate charging in SEM

Science.gov (United States)

Arat, K. T.; Klimpel, T.; Hagen, C. W.

2018-03-01

Charging of insulators is a complex phenomenon to simulate since the accuracy of the simulations is very sensitive to the interaction of electrons with matter and electric fields. In this study, we report model improvements for a previously developed Monte-Carlo simulator to more accurately simulate samples that charge. The improvements include both modelling of low energy electron scattering and charging of insulators. The new first-principle scattering models provide a more realistic charge distribution cloud in the material, and a better match between non-charging simulations and experimental results. Improvements on charging models mainly focus on redistribution of the charge carriers in the material with an induced conductivity (EBIC) and a breakdown model, leading to a smoother distribution of the charges. Combined with a more accurate tracing of low energy electrons in the electric field, we managed to reproduce the dynamically changing charging contrast due to an induced positive surface potential.

Profile control simulations and experiments on TCV: a controller test environment and results using a model-based predictive controller

Science.gov (United States)

Maljaars, E.; Felici, F.; Blanken, T. C.; Galperti, C.; Sauter, O.; de Baar, M. R.; Carpanese, F.; Goodman, T. P.; Kim, D.; Kim, S. H.; Kong, M.; Mavkov, B.; Merle, A.; Moret, J. M.; Nouailletas, R.; Scheffer, M.; Teplukhina, A. A.; Vu, N. M. T.; The EUROfusion MST1-team; The TCV-team

2017-12-01

The successful performance of a model predictive profile controller is demonstrated in simulations and experiments on the TCV tokamak, employing a profile controller test environment. Stable high-performance tokamak operation in hybrid and advanced plasma scenarios requires control over the safety factor profile (q-profile) and kinetic plasma parameters such as the plasma beta. This demands to establish reliable profile control routines in presently operational tokamaks. We present a model predictive profile controller that controls the q-profile and plasma beta using power requests to two clusters of gyrotrons and the plasma current request. The performance of the controller is analyzed in both simulation and TCV L-mode discharges where successful tracking of the estimated inverse q-profile as well as plasma beta is demonstrated under uncertain plasma conditions and the presence of disturbances. The controller exploits the knowledge of the time-varying actuator limits in the actuator input calculation itself such that fast transitions between targets are achieved without overshoot. A software environment is employed to prepare and test this and three other profile controllers in parallel in simulations and experiments on TCV. This set of tools includes the rapid plasma transport simulator RAPTOR and various algorithms to reconstruct the plasma equilibrium and plasma profiles by merging the available measurements with model-based predictions. In this work the estimated q-profile is merely based on RAPTOR model predictions due to the absence of internal current density measurements in TCV. These results encourage to further exploit model predictive profile control in experiments on TCV and other (future) tokamaks.

Mathematical model and simulations of radiation fluxes from buried radionuclides

International Nuclear Information System (INIS)

Ahmad Saat

1999-01-01

A mathematical model and a simple Monte Carlo simulations were developed to predict radiation fluxes from buried radionuclides. The model and simulations were applied to measured (experimental) data. The results of the mathematical model showed good acceptable order of magnitude agreement. A good agreement was also obtained between the simple simulations and the experimental results. Thus, knowing the radionuclide distribution profiles in soil from a core sample, it can be applied to the model or simulations to estimate the radiation fluxes emerging from the soil surface. (author)

Aviation Safety Simulation Model

Science.gov (United States)

Houser, Scott; Yackovetsky, Robert (Technical Monitor)

2001-01-01

The Aviation Safety Simulation Model is a software tool that enables users to configure a terrain, a flight path, and an aircraft and simulate the aircraft's flight along the path. The simulation monitors the aircraft's proximity to terrain obstructions, and reports when the aircraft violates accepted minimum distances from an obstruction. This model design facilitates future enhancements to address other flight safety issues, particularly air and runway traffic scenarios. This report shows the user how to build a simulation scenario and run it. It also explains the model's output.

Cognitive models embedded in system simulation models

International Nuclear Information System (INIS)

Siegel, A.I.; Wolf, J.J.

1982-01-01

If we are to discuss and consider cognitive models, we must first come to grips with two questions: (1) What is cognition; (2) What is a model. Presumably, the answers to these questions can provide a basis for defining a cognitive model. Accordingly, this paper first places these two questions into perspective. Then, cognitive models are set within the context of computer simulation models and a number of computer simulations of cognitive processes are described. Finally, pervasive issues are discussed vis-a-vis cognitive modeling in the computer simulation context

Modeling and simulating industrial land-use evolution in Shanghai, China

Science.gov (United States)

Qiu, Rongxu; Xu, Wei; Zhang, John; Staenz, Karl

2018-01-01

This study proposes a cellular automata-based Industrial and Residential Land Use Competition Model to simulate the dynamic spatial transformation of industrial land use in Shanghai, China. In the proposed model, land development activities in a city are delineated as competitions among different land-use types. The Hedonic Land Pricing Model is adopted to implement the competition framework. To improve simulation results, the Land Price Agglomeration Model was devised to simulate and adjust classic land price theory. A new evolutionary algorithm-based parameter estimation method was devised in place of traditional methods. Simulation results show that the proposed model closely resembles actual land transformation patterns and the model can not only simulate land development, but also redevelopment processes in metropolitan areas.

RHF RELAP5 model and preliminary loss-of-offsite-power simulation results for LEU conversion

Energy Technology Data Exchange (ETDEWEB)

Licht, J. R. [Argonne National Laboratory (ANL), Argonne, IL (United States). Nuclear Engineering Div.; Bergeron, A. [Argonne National Laboratory (ANL), Argonne, IL (United States). Nuclear Engineering Div.; Dionne, B. [Argonne National Laboratory (ANL), Argonne, IL (United States). Nuclear Engineering Div.; Thomas, F. [Institut Laue-Langevin (ILL), Grenoble (Switzerland). RHF Reactor Dept.

2014-08-01

The purpose of this document is to describe the current state of the RELAP5 model for the Institut Laue-Langevin High Flux Reactor (RHF) located in Grenoble, France, and provide an update to the key information required to complete, for example, simulations for a loss of offsite power (LOOP) accident. A previous status report identified a list of 22 items to be resolved in order to complete the RELAP5 model. Most of these items have been resolved by ANL and the RHF team. Enough information was available to perform preliminary safety analyses and define the key items that are still required. Section 2 of this document describes the RELAP5 model of RHF. The final part of this section briefly summarizes previous model issues and resolutions. Section 3 of this document describes preliminary LOOP simulations for both HEU and LEU fuel at beginning of cycle conditions.

Simulation platform to model, optimize and design wind turbines

Energy Technology Data Exchange (ETDEWEB)

Iov, F.; Hansen, A.D.; Soerensen, P.; Blaabjerg, F.

2004-03-01

This report is a general overview of the results obtained in the project 'Electrical Design and Control. Simulation Platform to Model, Optimize and Design Wind Turbines'. The motivation for this research project is the ever-increasing wind energy penetration into the power network. Therefore, the project has the main goal to create a model database in different simulation tools for a system optimization of the wind turbine systems. Using this model database a simultaneous optimization of the aerodynamic, mechanical, electrical and control systems over the whole range of wind speeds and grid characteristics can be achieved. The report is structured in six chapters. First, the background of this project and the main goals as well as the structure of the simulation platform is given. The main topologies for wind turbines, which have been taken into account during the project, are briefly presented. Then, the considered simulation tools namely: HAWC, DIgSILENT, Saber and Matlab/Simulink have been used in this simulation platform are described. The focus here is on the modelling and simulation time scale aspects. The abilities of these tools are complementary and they can together cover all the modelling aspects of the wind turbines e.g. mechanical loads, power quality, switching, control and grid faults. However, other simulation packages e.g PSCAD/EMTDC can easily be added in the simulation platform. New models and new control algorithms for wind turbine systems have been developed and tested in these tools. All these models are collected in dedicated libraries in Matlab/Simulink as well as in Saber. Some simulation results from the considered tools are presented for MW wind turbines. These simulation results focuses on fixed-speed and variable speed/pitch wind turbines. A good agreement with the real behaviour of these systems is obtained for each simulation tool. These models can easily be extended to model different kinds of wind turbines or large wind

Evaluation and comparison of models and modelling tools simulating nitrogen processes in treatment wetlands

DEFF Research Database (Denmark)

Edelfeldt, Stina; Fritzson, Peter

2008-01-01

with Modelica 2.1 (Wiley-IEEE Press, USA, 2004).] and an associated tool. The differences and similarities between the MathModelica Model Editor and three other ecological modelling tools have also been evaluated. The results show that the models can well be modelled and simulated in the MathModelica Model...... Editor, and that nitrogen decrease in a constructed treatment wetland should be described and simulated using the Nitrification/Denitrification model as this model has the highest overall quality score and provides a more variable environment.......In this paper, two ecological models of nitrogen processes in treatment wetlands have been evaluated and compared. These models were implemented, simulated, and visualized using the Modelica modelling and simulation language [P. Fritzson, Principles of Object-Oriented Modelling and Simulation...

Coupling of Large Eddy Simulations with Meteorological Models to simulate Methane Leaks from Natural Gas Storage Facilities

Science.gov (United States)

Prasad, K.

2017-12-01

Atmospheric transport is usually performed with weather models, e.g., the Weather Research and Forecasting (WRF) model that employs a parameterized turbulence model and does not resolve the fine scale dynamics generated by the flow around buildings and features comprising a large city. The NIST Fire Dynamics Simulator (FDS) is a computational fluid dynamics model that utilizes large eddy simulation methods to model flow around buildings at length scales much smaller than is practical with models like WRF. FDS has the potential to evaluate the impact of complex topography on near-field dispersion and mixing that is difficult to simulate with a mesoscale atmospheric model. A methodology has been developed to couple the FDS model with WRF mesoscale transport models. The coupling is based on nudging the FDS flow field towards that computed by WRF, and is currently limited to one way coupling performed in an off-line mode. This approach allows the FDS model to operate as a sub-grid scale model with in a WRF simulation. To test and validate the coupled FDS - WRF model, the methane leak from the Aliso Canyon underground storage facility was simulated. Large eddy simulations were performed over the complex topography of various natural gas storage facilities including Aliso Canyon, Honor Rancho and MacDonald Island at 10 m horizontal and vertical resolution. The goal of these simulations included improving and validating transport models as well as testing leak hypotheses. Forward simulation results were compared with aircraft and tower based in-situ measurements as well as methane plumes observed using the NASA Airborne Visible InfraRed Imaging Spectrometer (AVIRIS) and the next generation instrument AVIRIS-NG. Comparison of simulation results with measurement data demonstrate the capability of the coupled FDS-WRF models to accurately simulate the transport and dispersion of methane plumes over urban domains. Simulated integrated methane enhancements will be presented and

Modeling and simulation of complex systems a framework for efficient agent-based modeling and simulation

CERN Document Server

Siegfried, Robert

2014-01-01

Robert Siegfried presents a framework for efficient agent-based modeling and simulation of complex systems. He compares different approaches for describing structure and dynamics of agent-based models in detail. Based on this evaluation the author introduces the "General Reference Model for Agent-based Modeling and Simulation" (GRAMS). Furthermore he presents parallel and distributed simulation approaches for execution of agent-based models -from small scale to very large scale. The author shows how agent-based models may be executed by different simulation engines that utilize underlying hard

Modeling and simulation of satellite subsystems for end-to-end spacecraft modeling

Science.gov (United States)

Schum, William K.; Doolittle, Christina M.; Boyarko, George A.

2006-05-01

During the past ten years, the Air Force Research Laboratory (AFRL) has been simultaneously developing high-fidelity spacecraft payload models as well as a robust distributed simulation environment for modeling spacecraft subsystems. Much of this research has occurred in the Distributed Architecture Simulation Laboratory (DASL). AFRL developers working in the DASL have effectively combined satellite power, attitude pointing, and communication link analysis subsystem models with robust satellite sensor models to create a first-order end-to-end satellite simulation capability. The merging of these two simulation areas has advanced the field of spacecraft simulation, design, and analysis, and enabled more in-depth mission and satellite utility analyses. A core capability of the DASL is the support of a variety of modeling and analysis efforts, ranging from physics and engineering-level modeling to mission and campaign-level analysis. The flexibility and agility of this simulation architecture will be used to support space mission analysis, military utility analysis, and various integrated exercises with other military and space organizations via direct integration, or through DOD standards such as Distributed Interaction Simulation. This paper discusses the results and lessons learned in modeling satellite communication link analysis, power, and attitude control subsystems for an end-to-end satellite simulation. It also discusses how these spacecraft subsystem simulations feed into and support military utility and space mission analyses.

Advances in NLTE Modeling for Integrated Simulations

Energy Technology Data Exchange (ETDEWEB)

Scott, H A; Hansen, S B

2009-07-08

The last few years have seen significant progress in constructing the atomic models required for non-local thermodynamic equilibrium (NLTE) simulations. Along with this has come an increased understanding of the requirements for accurately modeling the ionization balance, energy content and radiative properties of different elements for a wide range of densities and temperatures. Much of this progress is the result of a series of workshops dedicated to comparing the results from different codes and computational approaches applied to a series of test problems. The results of these workshops emphasized the importance of atomic model completeness, especially in doubly excited states and autoionization transitions, to calculating ionization balance, and the importance of accurate, detailed atomic data to producing reliable spectra. We describe a simple screened-hydrogenic model that calculates NLTE ionization balance with surprising accuracy, at a low enough computational cost for routine use in radiation-hydrodynamics codes. The model incorporates term splitting, {Delta}n = 0 transitions, and approximate UTA widths for spectral calculations, with results comparable to those of much more detailed codes. Simulations done with this model have been increasingly successful at matching experimental data for laser-driven systems and hohlraums. Accurate and efficient atomic models are just one requirement for integrated NLTE simulations. Coupling the atomic kinetics to hydrodynamics and radiation transport constrains both discretizations and algorithms to retain energy conservation, accuracy and stability. In particular, the strong coupling between radiation and populations can require either very short timesteps or significantly modified radiation transport algorithms to account for NLTE material response. Considerations such as these continue to provide challenges for NLTE simulations.

Cognitive Modeling for Agent-Based Simulation of Child Maltreatment

Science.gov (United States)

Hu, Xiaolin; Puddy, Richard

This paper extends previous work to develop cognitive modeling for agent-based simulation of child maltreatment (CM). The developed model is inspired from parental efficacy, parenting stress, and the theory of planned behavior. It provides an explanatory, process-oriented model of CM and incorporates causality relationship and feedback loops from different factors in the social ecology in order for simulating the dynamics of CM. We describe the model and present simulation results to demonstrate the features of this model.

Modeling and simulation of the SDC data collection chip

International Nuclear Information System (INIS)

Hughes, E.; Haney, M.; Golin, E.; Jones, L.; Knapp, D.; Tharakan, G.; Downing, R.

1992-01-01

This paper describes modeling and simulation of the Data Collection Chip (DCC) design for the Solenoidal Detector Collaboration (SDC). Models of the DCC written in Verilog and VHDL are described, and results are presented. The models have been simulated to study queue depth requirements and to compare control feedback alternatives. Insight into the management of models and simulation tools is given. Finally, techniques useful in the design process for data acquisition systems are discussed

Experimental Design for Sensitivity Analysis of Simulation Models

NARCIS (Netherlands)

Kleijnen, J.P.C.

2001-01-01

This introductory tutorial gives a survey on the use of statistical designs for what if-or sensitivity analysis in simulation.This analysis uses regression analysis to approximate the input/output transformation that is implied by the simulation model; the resulting regression model is also known as

Simulation in Complex Modelling

DEFF Research Database (Denmark)

Nicholas, Paul; Ramsgaard Thomsen, Mette; Tamke, Martin

2017-01-01

This paper will discuss the role of simulation in extended architectural design modelling. As a framing paper, the aim is to present and discuss the role of integrated design simulation and feedback between design and simulation in a series of projects under the Complex Modelling framework. Complex...... performance, engage with high degrees of interdependency and allow the emergence of design agency and feedback between the multiple scales of architectural construction. This paper presents examples for integrated design simulation from a series of projects including Lace Wall, A Bridge Too Far and Inflated...... Restraint developed for the research exhibition Complex Modelling, Meldahls Smedie Gallery, Copenhagen in 2016. Where the direct project aims and outcomes have been reported elsewhere, the aim for this paper is to discuss overarching strategies for working with design integrated simulation....

Nuclear reactor core modelling in multifunctional simulators

International Nuclear Information System (INIS)

Puska, E.K.

1999-01-01

studied to assess the possibilities for using three-dimensional cores in training simulators. The core model results have been compared with the Loviisa WWER-type plant measurement data in steady state and in some transients. Hypothetical control rod withdrawal, ejection and boron dilution transients have been calculated with various three-dimensional core models for the Loviisa WWER-440 core. Several ATWS analyses for the WWER-1000/91 plant have been performed using the three-dimensional core model. In this context, the results of APROS have been compared in detail with the results of the HEXTRAN code. The three-dimensional Olkiluoto BWR-type core model has been used for transient calculation and for severe accident re-criticality studies. The one-dimensional core model is at present used in several plant analyser and training simulator applications and it has been used extensively for safety analyses in the Loviisa WWER-440 plant modernisation project. (orig.)

Nuclear reactor core modelling in multifunctional simulators

Energy Technology Data Exchange (ETDEWEB)

Puska, E.K. [VTT Energy, Nuclear Energy, Espoo (Finland)

1999-06-01

studied to assess the possibilities for using three-dimensional cores in training simulators. The core model results have been compared with the Loviisa WWER-type plant measurement data in steady state and in some transients. Hypothetical control rod withdrawal, ejection and boron dilution transients have been calculated with various three-dimensional core models for the Loviisa WWER-440 core. Several ATWS analyses for the WWER-1000/91 plant have been performed using the three-dimensional core model. In this context, the results of APROS have been compared in detail with the results of the HEXTRAN code. The three-dimensional Olkiluoto BWR-type core model has been used for transient calculation and for severe accident re-criticality studies. The one-dimensional core model is at present used in several plant analyser and training simulator applications and it has been used extensively for safety analyses in the Loviisa WWER-440 plant modernisation project. (orig.) 75 refs. The thesis includes also eight previous publications by author

Simulation-Based Internal Models for Safer Robots

Directory of Open Access Journals (Sweden)

Christian Blum

2018-01-01

Full Text Available In this paper, we explore the potential of mobile robots with simulation-based internal models for safety in highly dynamic environments. We propose a robot with a simulation of itself, other dynamic actors and its environment, inside itself. Operating in real time, this simulation-based internal model is able to look ahead and predict the consequences of both the robot’s own actions and those of the other dynamic actors in its vicinity. Hence, the robot continuously modifies its own actions in order to actively maintain its own safety while also achieving its goal. Inspired by the problem of how mobile robots could move quickly and safely through crowds of moving humans, we present experimental results which compare the performance of our internal simulation-based controller with a purely reactive approach as a proof-of-concept study for the practical use of simulation-based internal models.

Acquisition War-Gaming Technique for Acquiring Future Complex Systems: Modeling and Simulation Results for Cost Plus Incentive Fee Contract

Directory of Open Access Journals (Sweden)

Tien M. Nguyen

2018-03-01

Full Text Available This paper provides a high-level discussion and propositions of frameworks and models for acquisition strategy of complex systems. In particular, it presents an innovative system engineering approach to model the Department of Defense (DoD acquisition process and offers several optimization modules including simulation models using game theory and war-gaming concepts. Our frameworks employ Advanced Game-based Mathematical Framework (AGMF and Unified Game-based Acquisition Framework (UGAF, and related advanced simulation and mathematical models that include a set of War-Gaming Engines (WGEs implemented in MATLAB statistical optimization models. WGEs are defined as a set of algorithms, characterizing the Program and Technical Baseline (PTB, technology enablers, architectural solutions, contract type, contract parameters and associated incentives, and industry bidding position. As a proof of concept, Aerospace, in collaboration with the North Carolina State University (NCSU and University of Hawaii (UH, successfully applied and extended the proposed frameworks and decision models to determine the optimum contract parameters and incentives for a Cost Plus Incentive Fee (CPIF contract. As a result, we can suggest a set of acquisition strategies that ensure the optimization of the PTB.

A satellite simulator for TRMM PR applied to climate model simulations

Science.gov (United States)

Spangehl, T.; Schroeder, M.; Bodas-Salcedo, A.; Hollmann, R.; Riley Dellaripa, E. M.; Schumacher, C.

2017-12-01

Climate model simulations have to be compared against observation based datasets in order to assess their skill in representing precipitation characteristics. Here we use a satellite simulator for TRMM PR in order to evaluate simulations performed with MPI-ESM (Earth system model of the Max Planck Institute for Meteorology in Hamburg, Germany) performed within the MiKlip project (https://www.fona-miklip.de/, funded by Federal Ministry of Education and Research in Germany). While classical evaluation methods focus on geophysical parameters such as precipitation amounts, the application of the satellite simulator enables an evaluation in the instrument's parameter space thereby reducing uncertainties on the reference side. The CFMIP Observation Simulator Package (COSP) provides a framework for the application of satellite simulators to climate model simulations. The approach requires the introduction of sub-grid cloud and precipitation variability. Radar reflectivities are obtained by applying Mie theory, with the microphysical assumptions being chosen to match the atmosphere component of MPI-ESM (ECHAM6). The results are found to be sensitive to the methods used to distribute the convective precipitation over the sub-grid boxes. Simple parameterization methods are used to introduce sub-grid variability of convective clouds and precipitation. In order to constrain uncertainties a comprehensive comparison with sub-grid scale convective precipitation variability which is deduced from TRMM PR observations is carried out.

Some GCM simulation results on present and possible future climate in northern Europe

Energy Technology Data Exchange (ETDEWEB)

Raeisaenen, J [Helsinki Univ. (Finland). Dept. of Meteorology

1996-12-31

The Intergovernmental Panel on Climate Change initiated in 1993 a project entitled `Evaluation of Regional Climate Simulations`. The two basic aims of this project were to assess the skill of current general circulation models (GCMs) in simulating present climate at a regional level and to intercompare the regional response of various GCMs to increased greenhouse gas concentrations. The public data base established for the comparison included simulation results from several modelling centres, but most of the data were available in the form of time-averaged seasonal means only, and important quantities like precipitation were totally lacking in many cases. This presentation summarizes the intercomparison results for surface air temperature and sea level pressure in northern Europe. The quality of the control simulations and the response of the models to increased CO{sub 2} are addressed in both winter (December-February) and summer (June-August)

Some GCM simulation results on present and possible future climate in northern Europe

Energy Technology Data Exchange (ETDEWEB)

Raeisaenen, J. [Helsinki Univ. (Finland). Dept. of Meteorology

1995-12-31

The Intergovernmental Panel on Climate Change initiated in 1993 a project entitled `Evaluation of Regional Climate Simulations`. The two basic aims of this project were to assess the skill of current general circulation models (GCMs) in simulating present climate at a regional level and to intercompare the regional response of various GCMs to increased greenhouse gas concentrations. The public data base established for the comparison included simulation results from several modelling centres, but most of the data were available in the form of time-averaged seasonal means only, and important quantities like precipitation were totally lacking in many cases. This presentation summarizes the intercomparison results for surface air temperature and sea level pressure in northern Europe. The quality of the control simulations and the response of the models to increased CO{sub 2} are addressed in both winter (December-February) and summer (June-August)

Influence of the quantum well models on the numerical simulation of planar InGaN/GaN LED results

International Nuclear Information System (INIS)

Podgórski, J; Woźny, J; Lisik, Z

2016-01-01

Within this paper, we present electric model of a light emitting diode (LED) made of gallium nitride (GaN) followed by examples of simulation results obtained by means of Sentaurus software, which is the part of the TCAD package. The aim of this work is to answer the question of whether physical models of quantum wells used in commercial software are suitable for a correct analysis of the lateral LEDs made of GaN. (paper)

Electron-cloud updated simulation results for the PSR, and recent results for the SNS

International Nuclear Information System (INIS)

Pivi, M.; Furman, M.A.

2002-01-01

Recent simulation results for the main features of the electron cloud in the storage ring of the Spallation Neutron Source (SNS) at Oak Ridge, and updated results for the Proton Storage Ring (PSR) at Los Alamos are presented in this paper. A refined model for the secondary emission process including the so called true secondary, rediffused and backscattered electrons has recently been included in the electron-cloud code

Dynamic wind turbine models in power system simulation tool

DEFF Research Database (Denmark)

Hansen, A.; Jauch, Clemens; Soerensen, P.

The present report describes the dynamic wind turbine models implemented in the power system simulation tool DIgSILENT. The developed models are a part of the results of a national research project, whose overall objective is to create a model database in different simulation tools. The report...

Simulation and analysis of a model dinoflagellate predator-prey system

Science.gov (United States)

Mazzoleni, M. J.; Antonelli, T.; Coyne, K. J.; Rossi, L. F.

2015-12-01

This paper analyzes the dynamics of a model dinoflagellate predator-prey system and uses simulations to validate theoretical and experimental studies. A simple model for predator-prey interactions is derived by drawing upon analogies from chemical kinetics. This model is then modified to account for inefficiencies in predation. Simulation results are shown to closely match the model predictions. Additional simulations are then run which are based on experimental observations of predatory dinoflagellate behavior, and this study specifically investigates how the predatory dinoflagellate Karlodinium veneficum uses toxins to immobilize its prey and increase its feeding rate. These simulations account for complex dynamics that were not included in the basic models, and the results from these computational simulations closely match the experimentally observed predatory behavior of K. veneficum and reinforce the notion that predatory dinoflagellates utilize toxins to increase their feeding rate.

Variable slip wind generator modeling for real-time simulation

Energy Technology Data Exchange (ETDEWEB)

Gagnon, R.; Brochu, J.; Turmel, G. [Hydro-Quebec, Varennes, PQ (Canada). IREQ

2006-07-01

A model of a wind turbine using a variable slip wound-rotor induction machine was presented. The model was created as part of a library of generic wind generator models intended for wind integration studies. The stator winding of the wind generator was connected directly to the grid and the rotor was driven by the turbine through a drive train. The variable resistors was synthesized by an external resistor in parallel with a diode rectifier. A forced-commutated power electronic device (IGBT) was connected to the wound rotor by slip rings and brushes. Simulations were conducted in a Matlab/Simulink environment using SimPowerSystems blocks to model power systems elements and Simulink blocks to model the turbine, control system and drive train. Detailed descriptions of the turbine, the drive train and the control system were provided. The model's implementation in the simulator was also described. A case study demonstrating the real-time simulation of a wind generator connected at the distribution level of a power system was presented. Results of the case study were then compared with results obtained from the SimPowerSystems off-line simulation. Results showed good agreement between the waveforms, demonstrating the conformity of the real-time and the off-line simulations. The capability of Hypersim for real-time simulation of wind turbines with power electronic converters in a distribution network was demonstrated. It was concluded that hardware-in-the-loop (HIL) simulation of wind turbine controllers for wind integration studies in power systems is now feasible. 5 refs., 1 tab., 6 figs.

Evolution Model and Simulation of Profit Model of Agricultural Products Logistics Financing

Science.gov (United States)

Yang, Bo; Wu, Yan

2018-03-01

Agricultural products logistics financial warehousing business mainly involves agricultural production and processing enterprises, third-party logistics enterprises and financial institutions tripartite, to enable the three parties to achieve win-win situation, the article first gives the replication dynamics and evolutionary stability strategy between the three parties in business participation, and then use NetLogo simulation platform, using the overall modeling and simulation method of Multi-Agent, established the evolutionary game simulation model, and run the model under different revenue parameters, finally, analyzed the simulation results. To achieve the agricultural products logistics financial financing warehouse business to participate in tripartite mutually beneficial win-win situation, thus promoting the smooth flow of agricultural products logistics business.

Computer Modeling and Simulation

Energy Technology Data Exchange (ETDEWEB)

Pronskikh, V. S. [Fermilab

2014-05-09

Verification and validation of computer codes and models used in simulation are two aspects of the scientific practice of high importance and have recently been discussed by philosophers of science. While verification is predominantly associated with the correctness of the way a model is represented by a computer code or algorithm, validation more often refers to model’s relation to the real world and its intended use. It has been argued that because complex simulations are generally not transparent to a practitioner, the Duhem problem can arise for verification and validation due to their entanglement; such an entanglement makes it impossible to distinguish whether a coding error or model’s general inadequacy to its target should be blamed in the case of the model failure. I argue that in order to disentangle verification and validation, a clear distinction between computer modeling (construction of mathematical computer models of elementary processes) and simulation (construction of models of composite objects and processes by means of numerical experimenting with them) needs to be made. Holding on to that distinction, I propose to relate verification (based on theoretical strategies such as inferences) to modeling and validation, which shares the common epistemology with experimentation, to simulation. To explain reasons of their intermittent entanglement I propose a weberian ideal-typical model of modeling and simulation as roles in practice. I suggest an approach to alleviate the Duhem problem for verification and validation generally applicable in practice and based on differences in epistemic strategies and scopes

Vehicle dynamics modeling and simulation

CERN Document Server

Schramm, Dieter; Bardini, Roberto

2014-01-01

The authors examine in detail the fundamentals and mathematical descriptions of the dynamics of automobiles. In this context different levels of complexity will be presented, starting with basic single-track models up to complex three-dimensional multi-body models. A particular focus is on the process of establishing mathematical models on the basis of real cars and the validation of simulation results. The methods presented are explained in detail by means of selected application scenarios.

Modeling And Simulation Of Combined Extrusion For Spark Plug Body Parts

Science.gov (United States)

Canta, T.; Noveanu, D.; Frunza, D.

2004-06-01

The paper presents the modeling and simulation for the extrusion technology of a new type of spark plug body for Dacia Supernova car. This technology was simulated using the finite elements modeling and analysis SuperForm software, designed for the simulation of plastic deformation processes. There is also presented a comparison between the results of the simulation and the industrial results.

Dispersion modeling by kinematic simulation: Cloud dispersion model

International Nuclear Information System (INIS)

Fung, J C H; Perkins, R J

2008-01-01

A new technique has been developed to compute mean and fluctuating concentrations in complex turbulent flows (tidal current near a coast and deep ocean). An initial distribution of material is discretized into any small clouds which are advected by a combination of the mean flow and large scale turbulence. The turbulence can be simulated either by kinematic simulation (KS) or direct numerical simulation. The clouds also diffuse relative to their centroids; the statistics for this are obtained from a separate calculation of the growth of individual clouds in small scale turbulence, generated by KS. The ensemble of discrete clouds is periodically re-discretized, to limit the size of the small clouds and prevent overlapping. The model is illustrated with simulations of dispersion in uniform flow, and the results are compared with analytic, steady state solutions. The aim of this study is to understand how pollutants disperses in a turbulent flow through a numerical simulation of fluid particle motion in a random flow field generated by Fourier modes. Although this homogeneous turbulent is rather a 'simple' flow, it represents a building block toward understanding pollutant dispersion in more complex flow. The results presented here are preliminary in nature, but we expect that similar qualitative results should be observed in a genuine turbulent flow.

Simulation of finite size effects of the fiber bundle model

Science.gov (United States)

Hao, Da-Peng; Tang, Gang; Xun, Zhi-Peng; Xia, Hui; Han, Kui

2018-01-01

In theory, the macroscopic fracture of materials should correspond with the thermodynamic limit of the fiber bundle model. However, the simulation of a fiber bundle model with an infinite size is unrealistic. To study the finite size effects of the fiber bundle model, fiber bundle models of various size are simulated in detail. The effects of system size on the constitutive behavior, critical stress, maximum avalanche size, avalanche size distribution, and increased step number of external load are explored. The simulation results imply that there is no feature size or cut size for macroscopic mechanical and statistical properties of the model. The constitutive curves near the macroscopic failure for various system size can collapse well with a simple scaling relationship. Simultaneously, the introduction of a simple extrapolation method facilitates the acquisition of more accurate simulation results in a large-limit system, which is better for comparison with theoretical results.

An ocular biomechanic model for dynamic simulation of different eye movements.

Science.gov (United States)

Iskander, J; Hossny, M; Nahavandi, S; Del Porto, L

2018-04-11

Simulating and analysing eye movement is useful for assessing visual system contribution to discomfort with respect to body movements, especially in virtual environments where simulation sickness might occur. It can also be used in the design of eye prosthesis or humanoid robot eye. In this paper, we present two biomechanic ocular models that are easily integrated into the available musculoskeletal models. The model was previously used to simulate eye-head coordination. The models are used to simulate and analyse eye movements. The proposed models are based on physiological and kinematic properties of the human eye. They incorporate an eye-globe, orbital suspension tissues and six muscles with their connective tissues (pulleys). Pulleys were incorporated in rectus and inferior oblique muscles. The two proposed models are the passive pulleys and the active pulleys models. Dynamic simulations of different eye movements, including fixation, saccade and smooth pursuit, are performed to validate both models. The resultant force-length curves of the models were similar to the experimental data. The simulation results show that the proposed models are suitable to generate eye movement simulations with results comparable to other musculoskeletal models. The maximum kinematic root mean square error (RMSE) is 5.68° and 4.35° for the passive and active pulley models, respectively. The analysis of the muscle forces showed realistic muscle activation with increased muscle synergy in the active pulley model. Copyright © 2018 Elsevier Ltd. All rights reserved.

Co-simulation of dynamic systems in parallel and serial model configurations

International Nuclear Information System (INIS)

Sweafford, Trevor; Yoon, Hwan Sik

2013-01-01

Recent advancement in simulation software and computation hardware make it realizable to simulate complex dynamic systems comprised of multiple submodels developed in different modeling languages. The so-called co-simulation enables one to study various aspects of a complex dynamic system with heterogeneous submodels in a cost-effective manner. Among several different model configurations for co-simulation, synchronized parallel configuration is regarded to expedite the simulation process by simulation multiple sub models concurrently on a multi core processor. In this paper, computational accuracies as well as computation time are studied for three different co-simulation frameworks : integrated, serial, and parallel. for this purpose, analytical evaluations of the three different methods are made using the explicit Euler method and then they are applied to two-DOF mass-spring systems. The result show that while the parallel simulation configuration produces the same accurate results as the integrated configuration, results of the serial configuration, results of the serial configuration show a slight deviation. it is also shown that the computation time can be reduced by running simulation in the parallel configuration. Therefore, it can be concluded that the synchronized parallel simulation methodology is the best for both simulation accuracy and time efficiency.

Modeling and simulating combustion and generation of NOx

International Nuclear Information System (INIS)

Lazaroiu, Gheorghe

2007-01-01

This paper deals with the modeling and simulation of combustion processes and generation of NO x in a combustion chamber and boiler, with supplementary combustion in a gas turbine installation. The fuel burned in the combustion chamber was rich gas with a chemical composition more complex than natural gas. Pitcoal was used in the regenerative boiler. From the resulting combustion products, 17 compounds were retained, including nitrogen and sulphur compounds. Using the developed model, the simulation resulted in excess air for a temperature imposed at the combustion chamber exhaust. These simulations made it possible to determine the concentrations of combustion compounds with a variation in excess combustion. (author)

Simulation Models for Socioeconomic Inequalities in Health: A Systematic Review

Directory of Open Access Journals (Sweden)

Niko Speybroeck

2013-11-01

Full Text Available Background: The emergence and evolution of socioeconomic inequalities in health involves multiple factors interacting with each other at different levels. Simulation models are suitable for studying such complex and dynamic systems and have the ability to test the impact of policy interventions in silico. Objective: To explore how simulation models were used in the field of socioeconomic inequalities in health. Methods: An electronic search of studies assessing socioeconomic inequalities in health using a simulation model was conducted. Characteristics of the simulation models were extracted and distinct simulation approaches were identified. As an illustration, a simple agent-based model of the emergence of socioeconomic differences in alcohol abuse was developed. Results: We found 61 studies published between 1989 and 2013. Ten different simulation approaches were identified. The agent-based model illustration showed that multilevel, reciprocal and indirect effects of social determinants on health can be modeled flexibly. Discussion and Conclusions: Based on the review, we discuss the utility of using simulation models for studying health inequalities, and refer to good modeling practices for developing such models. The review and the simulation model example suggest that the use of simulation models may enhance the understanding and debate about existing and new socioeconomic inequalities of health frameworks.

Validating clustering of molecular dynamics simulations using polymer models

Directory of Open Access Journals (Sweden)

Phillips Joshua L

2011-11-01

Full Text Available Abstract Background Molecular dynamics (MD simulation is a powerful technique for sampling the meta-stable and transitional conformations of proteins and other biomolecules. Computational data clustering has emerged as a useful, automated technique for extracting conformational states from MD simulation data. Despite extensive application, relatively little work has been done to determine if the clustering algorithms are actually extracting useful information. A primary goal of this paper therefore is to provide such an understanding through a detailed analysis of data clustering applied to a series of increasingly complex biopolymer models. Results We develop a novel series of models using basic polymer theory that have intuitive, clearly-defined dynamics and exhibit the essential properties that we are seeking to identify in MD simulations of real biomolecules. We then apply spectral clustering, an algorithm particularly well-suited for clustering polymer structures, to our models and MD simulations of several intrinsically disordered proteins. Clustering results for the polymer models provide clear evidence that the meta-stable and transitional conformations are detected by the algorithm. The results for the polymer models also help guide the analysis of the disordered protein simulations by comparing and contrasting the statistical properties of the extracted clusters. Conclusions We have developed a framework for validating the performance and utility of clustering algorithms for studying molecular biopolymer simulations that utilizes several analytic and dynamic polymer models which exhibit well-behaved dynamics including: meta-stable states, transition states, helical structures, and stochastic dynamics. We show that spectral clustering is robust to anomalies introduced by structural alignment and that different structural classes of intrinsically disordered proteins can be reliably discriminated from the clustering results. To our

Relative importance of secondary settling tank models in WWTP simulations

DEFF Research Database (Denmark)

Ramin, Elham; Flores-Alsina, Xavier; Sin, Gürkan

2012-01-01

Results obtained in a study using the Benchmark Simulation Model No. 1 (BSM1) show that a one-dimensional secondary settling tank (1-D SST) model structure and its parameters are among the most significant sources of uncertainty in wastewater treatment plant (WWTP) simulations [Ramin et al., 2011......]. The sensitivity results consistently indicate that the prediction of sludge production is most sensitive to the variation of the settling parameters. In the present study, we use the Benchmark Simulation Model No. 2 (BSM2), a plant-wide benchmark, that combines the Activated Sludge Model No. 1 (ASM1...

Notes on modeling and simulation

Energy Technology Data Exchange (ETDEWEB)

Redondo, Antonio [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-03-10

These notes present a high-level overview of how modeling and simulation are carried out by practitioners. The discussion is of a general nature; no specific techniques are examined but the activities associated with all modeling and simulation approaches are briefly addressed. There is also a discussion of validation and verification and, at the end, a section on why modeling and simulation are useful.

Computer simulations of the random barrier model

DEFF Research Database (Denmark)

Schrøder, Thomas; Dyre, Jeppe

2002-01-01

A brief review of experimental facts regarding ac electronic and ionic conduction in disordered solids is given followed by a discussion of what is perhaps the simplest realistic model, the random barrier model (symmetric hopping model). Results from large scale computer simulations are presented...

TransCom model simulations of hourly atmospheric CO2: Experimental overview and diurnal cycle results for 2002

NARCIS (Netherlands)

Law, R. M.; Peters, W.; RöDenbeck, C.; Aulagnier, C.; Baker, I.; Bergmann, D. J.; Bousquet, P.; Brandt, J.; Bruhwiler, L.; Cameron-Smith, P. J.; Christensen, J. H.; Delage, F.; Denning, A. S.; Fan, S.; Geels, C.; Houweling, S.; Imasu, R.; Karstens, U.; Kawa, S. R.; Kleist, J.; Krol, M. C.; Lin, S.-J.; Lokupitiya, R.; Maki, T.; Maksyutov, S.; Niwa, Y.; Onishi, R.; Parazoo, N.; Patra, P. K.; Pieterse, G.; Rivier, L.; Satoh, M.; Serrar, S.; Taguchi, S.; Takigawa, M.; Vautard, R.; Vermeulen, A. T.; Zhu, Z.

2008-01-01

A forward atmospheric transport modeling experiment has been coordinated by the TransCom group to investigate synoptic and diurnal variations in CO2. Model simulations were run for biospheric, fossil, and air-sea exchange of CO2 and for SF6 and radon for 2000-2003. Twenty-five models or model

Regional model simulations of New Zealand climate

Science.gov (United States)

Renwick, James A.; Katzfey, Jack J.; Nguyen, Kim C.; McGregor, John L.

1998-03-01

Simulation of New Zealand climate is examined through the use of a regional climate model nested within the output of the Commonwealth Scientific and Industrial Research Organisation nine-level general circulation model (GCM). R21 resolution GCM output is used to drive a regional model run at 125 km grid spacing over the Australasian region. The 125 km run is used in turn to drive a simulation at 50 km resolution over New Zealand. Simulations with a full seasonal cycle are performed for 10 model years. The focus is on the quality of the simulation of present-day climate, but results of a doubled-CO2 run are discussed briefly. Spatial patterns of mean simulated precipitation and surface temperatures improve markedly as horizontal resolution is increased, through the better resolution of the country's orography. However, increased horizontal resolution leads to a positive bias in precipitation. At 50 km resolution, simulated frequency distributions of daily maximum/minimum temperatures are statistically similar to those of observations at many stations, while frequency distributions of daily precipitation appear to be statistically different to those of observations at most stations. Modeled daily precipitation variability at 125 km resolution is considerably less than observed, but is comparable to, or exceeds, observed variability at 50 km resolution. The sensitivity of the simulated climate to changes in the specification of the land surface is discussed briefly. Spatial patterns of the frequency of extreme temperatures and precipitation are generally well modeled. Under a doubling of CO2, the frequency of precipitation extremes changes only slightly at most locations, while air frosts become virtually unknown except at high-elevation sites.

General introduction to simulation models

DEFF Research Database (Denmark)

Hisham Beshara Halasa, Tariq; Boklund, Anette

2012-01-01

trials. However, if simulation models would be used, good quality input data must be available. To model FMD, several disease spread models are available. For this project, we chose three simulation model; Davis Animal Disease Spread (DADS), that has been upgraded to DTU-DADS, InterSpread Plus (ISP......Monte Carlo simulation can be defined as a representation of real life systems to gain insight into their functions and to investigate the effects of alternative conditions or actions on the modeled system. Models are a simplification of a system. Most often, it is best to use experiments and field...... trials to investigate the effect of alternative conditions or actions on a specific system. Nonetheless, field trials are expensive and sometimes not possible to conduct, as in case of foot-and-mouth disease (FMD). Instead, simulation models can be a good and cheap substitute for experiments and field...

Summarizing Simulation Results using Causally-relevant States

Science.gov (United States)

Parikh, Nidhi; Marathe, Madhav; Swarup, Samarth

2016-01-01

As increasingly large-scale multiagent simulations are being implemented, new methods are becoming necessary to make sense of the results of these simulations. Even concisely summarizing the results of a given simulation run is a challenge. Here we pose this as the problem of simulation summarization: how to extract the causally-relevant descriptions of the trajectories of the agents in the simulation. We present a simple algorithm to compress agent trajectories through state space by identifying the state transitions which are relevant to determining the distribution of outcomes at the end of the simulation. We present a toy-example to illustrate the working of the algorithm, and then apply it to a complex simulation of a major disaster in an urban area. PMID:28042620

Protein adsorption on nanoparticles: model development using computer simulation

International Nuclear Information System (INIS)

Shao, Qing; Hall, Carol K

2016-01-01

The adsorption of proteins on nanoparticles results in the formation of the protein corona, the composition of which determines how nanoparticles influence their biological surroundings. We seek to better understand corona formation by developing models that describe protein adsorption on nanoparticles using computer simulation results as data. Using a coarse-grained protein model, discontinuous molecular dynamics simulations are conducted to investigate the adsorption of two small proteins (Trp-cage and WW domain) on a model nanoparticle of diameter 10.0 nm at protein concentrations ranging from 0.5 to 5 mM. The resulting adsorption isotherms are well described by the Langmuir, Freundlich, Temkin and Kiselev models, but not by the Elovich, Fowler–Guggenheim and Hill–de Boer models. We also try to develop a generalized model that can describe protein adsorption equilibrium on nanoparticles of different diameters in terms of dimensionless size parameters. The simulation results for three proteins (Trp-cage, WW domain, and GB3) on four nanoparticles (diameter  =  5.0, 10.0, 15.0, and 20.0 nm) illustrate both the promise and the challenge associated with developing generalized models of protein adsorption on nanoparticles. (paper)

TransCom model simulations of hourly atmospheric CO2: Experimental overview and diurnal cycle results for 2002

NARCIS (Netherlands)

Law, R. M.; Peters, W.; Roedenbeck, C.; Aulagnier, C.; Baker, I.; Bergmann, D. J.; Bousquet, P.; Brandt, J.; Bruhwiler, L.; Cameron-Smith, P. J.; Christensen, J. H.; Delage, F.; Denning, A. S.; Fan, S.; Geels, C.; Houweling, S.; Imasu, R.; Karstens, U.; Kawa, S. R.; Kleist, J.; Krol, M. C.; Lin, S. -J.; Lokupitiya, R.; Maki, T.; Maksyutov, S.; Niwa, Y.; Onishi, R.; Parazoo, N.; Patra, P. K.; Pieterse, G.; Rivier, L.; Satoh, M.; Serrar, S.; Taguchi, S.; Takigawa, M.; Vautard, R.; Vermeulen, A. T.; Zhu, Z.

2008-01-01

[1] A forward atmospheric transport modeling experiment has been coordinated by the TransCom group to investigate synoptic and diurnal variations in CO2. Model simulations were run for biospheric, fossil, and air-sea exchange of CO2 and for SF6 and radon for 2000-2003. Twenty-five models or model

Impact of reactive settler models on simulated WWTP performance

DEFF Research Database (Denmark)

Gernaey, Krist; Jeppsson, Ulf; Batstone, Damien J.

2006-01-01

for an ASM1 case study. Simulations with a whole plant model including the non-reactive Takacs settler model are used as a reference, and are compared to simulation results considering two reactive settler models. The first is a return sludge model block removing oxygen and a user-defined fraction of nitrate......, combined with a non-reactive Takacs settler. The second is a fully reactive ASM1 Takacs settler model. Simulations with the ASM1 reactive settler model predicted a 15.3% and 7.4% improvement of the simulated N removal performance, for constant (steady-state) and dynamic influent conditions respectively....... The oxygen/nitrate return sludge model block predicts a 10% improvement of N removal performance under dynamic conditions, and might be the better modelling option for ASM1 plants: it is computationally more efficient and it will not overrate the importance of decay processes in the settler....

ECONOMIC MODELING STOCKS CONTROL SYSTEM: SIMULATION MODEL

OpenAIRE

Климак, М.С.; Войтко, С.В.

2016-01-01

Considered theoretical and applied aspects of the development of simulation models to predictthe optimal development and production systems that create tangible products andservices. It isproved that theprocessof inventory control needs of economicandmathematical modeling in viewof thecomplexity of theoretical studies. A simulation model of stocks control that allows make managementdecisions with production logistics

Simulation of root forms using cellular automata model

International Nuclear Information System (INIS)

Winarno, Nanang; Prima, Eka Cahya; Afifah, Ratih Mega Ayu

2016-01-01

This research aims to produce a simulation program for root forms using cellular automata model. Stephen Wolfram in his book entitled “A New Kind of Science” discusses the formation rules based on the statistical analysis. In accordance with Stephen Wolfram’s investigation, the research will develop a basic idea of computer program using Delphi 7 programming language. To best of our knowledge, there is no previous research developing a simulation describing root forms using the cellular automata model compared to the natural root form with the presence of stone addition as the disturbance. The result shows that (1) the simulation used four rules comparing results of the program towards the natural photographs and each rule had shown different root forms; (2) the stone disturbances prevent the root growth and the multiplication of root forms had been successfully modeled. Therefore, this research had added some stones, which have size of 120 cells placed randomly in the soil. Like in nature, stones cannot be penetrated by plant roots. The result showed that it is very likely to further develop the program of simulating root forms by 50 variations

Simulation of root forms using cellular automata model

Energy Technology Data Exchange (ETDEWEB)

Winarno, Nanang, E-mail: nanang-winarno@upi.edu; Prima, Eka Cahya [International Program on Science Education, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi no 229, Bandung40154 (Indonesia); Afifah, Ratih Mega Ayu [Department of Physics Education, Post Graduate School, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi no 229, Bandung40154 (Indonesia)

2016-02-08

This research aims to produce a simulation program for root forms using cellular automata model. Stephen Wolfram in his book entitled “A New Kind of Science” discusses the formation rules based on the statistical analysis. In accordance with Stephen Wolfram’s investigation, the research will develop a basic idea of computer program using Delphi 7 programming language. To best of our knowledge, there is no previous research developing a simulation describing root forms using the cellular automata model compared to the natural root form with the presence of stone addition as the disturbance. The result shows that (1) the simulation used four rules comparing results of the program towards the natural photographs and each rule had shown different root forms; (2) the stone disturbances prevent the root growth and the multiplication of root forms had been successfully modeled. Therefore, this research had added some stones, which have size of 120 cells placed randomly in the soil. Like in nature, stones cannot be penetrated by plant roots. The result showed that it is very likely to further develop the program of simulating root forms by 50 variations.

The development of fully dynamic rotating machine models for nuclear training simulators

International Nuclear Information System (INIS)

Birsa, J.J.

1990-01-01

Prior to beginning the development of an enhanced set of electrical plant models for several nuclear training simulators, an extensive literature search was conducted to evaluate and select rotating machine models for use on these simulators. These models include the main generator, diesel generators, in-plant electric power distribution and off-side power. Form the results of this search, various models were investigated and several were selected for further evaluation. Several computer studies were performed on the selected models in order to determine their suitability for use in a training simulator environment. One surprising result of this study was that a number of established, classical models could not be made to reproduce actual plant steady-state data over the range necessary for a training simulator. This evaluation process and its results are presented in this paper. Various historical, as well as contemporary, electrical models of rotating machines are discussed. Specific criteria for selection of rotating machine models for training simulator use are presented

ANALYTICAL AND SIMULATION PLANNING MODEL OF URBAN PASSENGER TRANSPORT

Directory of Open Access Journals (Sweden)

Andrey Borisovich Nikolaev

2017-09-01

Full Text Available The article described the structure of the analytical and simulation models to make informed decisions in the planning of urban passenger transport. Designed UML diagram that describes the relationship of classes of the proposed model. A description of the main agents of the model developed in the simulation AnyLogic. Designed user interface integration with GIS map. Also provides simulation results that allow concluding about her health and the possibility of its use in solving planning problems of urban passenger transport.

Simulation modelling of fynbos ecosystems: Systems analysis and conceptual models

CSIR Research Space (South Africa)

Kruger, FJ

1985-03-01

Full Text Available -animal interactions. An additional two models, which expand aspects of the FYNBOS model, are described: a model for simulating canopy processes; and a Fire Recovery Simulator. The canopy process model will simulate ecophysiological processes in more detail than FYNBOS...

Pedestrians’ behavior in emergency evacuation: Modeling and simulation

Science.gov (United States)

Wang, Lei; Zheng, Jie-Hui; Zhang, Xiao-Shuang; Zhang, Jian-Lin; Wang, Qiu-Zhen; Zhang, Qian

2016-11-01

The social force model has been widely used to simulate pedestrian evacuation by analyzing attractive, repulsive, driving, and fluctuating forces among pedestrians. Many researchers have improved its limitations in simulating behaviors of large-scale population. This study modifies the well-accepted social force model by considering the impacts of interaction among companions and further develops a comprehensive model by combining that with a multi-exit utility function. Then numerical simulations of evacuations based on the comprehensive model are implemented in the waiting hall of the Wulin Square Subway Station in Hangzhou, China. The results provide safety thresholds of pedestrian density and panic levels in different operation situations. In spite of the operation situation and the panic level, a larger friend-group size results in lower evacuation efficiency. Our study makes important contributions to building a comprehensive multi-exit social force model and to applying it to actual scenarios, which produces data to facilitate decision making in contingency plans and emergency treatment. Project supported by the National Natural Science Foundation of China (Grant No. 71471163).

Proceedings of the 17. IASTED international conference on modelling and simulation

Energy Technology Data Exchange (ETDEWEB)

Wamkeue, R. (comp.) [Quebec Univ., Abitibi-Temiscaminque, PQ (Canada)

2006-07-01

The International Association of Science and Technology for Development (IASTED) hosted this conference to provide a forum for international researchers and practitioners interested in all areas of modelling and simulation. The conference featured 12 sessions entitled: (1) automation, control and robotics, (2) hydraulic and hydrologic modelling, (3) applications in processes and design optimization, (4) environmental systems, (5) biomedicine and biomechanics, (6) communications, computers and informatics 1, (7) economics, management and operations research 1, (8) modelling and simulation methodologies 1, (9) economics, management and operations research 2, (10) modelling, optimization, identification and simulation, (11) communications, computers and informatics 2, and, (12) modelling and simulation methodologies 2. Participants took the opportunity to present the latest research, results, and ideas in mathematical modelling; physically-based modelling; agent-based modelling; dynamic modelling; 3-dimensional modelling; computational geometry; time series analysis; finite element methods; discrete event simulation; web-based simulation; Monte Carlo simulation; simulation optimization; simulation uncertainty; fuzzy systems; data modelling; computer aided design; and, visualization. Case studies in engineering design were also presented along with simulation tools and languages. The conference also highlighted topical issues in environmental systems modelling such as air modelling and simulation, atmospheric modelling, hazardous materials, mobile source emissions, ecosystem modelling, hydrological modelling, aquatic ecosystems, terrestrial ecosystems, biological systems, agricultural modelling, terrain analysis, meteorological modelling, earth system modelling, climatic modelling, and natural resource management. The conference featured 110 presentations, of which 3 have been catalogued separately for inclusion in this database. refs., tabs., figs.

Comparisons of the simulation results using different codes for ADS spallation target

International Nuclear Information System (INIS)

Yu Hongwei; Fan Sheng; Shen Qingbiao; Zhao Zhixiang; Wan Junsheng

2002-01-01

The calculations to the standard thick target were made by using different codes. The simulation of the thick Pb target with length of 60 cm, diameter of 20 cm bombarded with 800, 1000, 1500 and 2000 MeV energetic proton beam was carried out. The yields and the spectra of emitted neutron were studied. The spallation target was simulated by SNSP, SHIELD, DCM/CEM (Dubna Cascade Model /Cascade Evaporation Mode) and LAHET codes. The Simulation Results were compared with experiments. The comparisons show good agreement between the experiments and the SNSP simulated leakage neutron yield. The SHIELD simulated leakage neutron spectra are in good agreement with the LAHET and the DCM/CEM simulated leakage neutron spectra

Integrated predictive modeling simulations of the Mega-Amp Spherical Tokamak

International Nuclear Information System (INIS)

Nguyen, Canh N.; Bateman, Glenn; Kritz, Arnold H.; Akers, Robert; Byrom, Calum; Sykes, Alan

2002-01-01

Integrated predictive modeling simulations are carried out using the BALDUR transport code [Singer et al., Comput. Phys. Commun. 49, 275 (1982)] for high confinement mode (H-mode) and low confinement mode (L-mode) discharges in the Mega-Amp Spherical Tokamak (MAST) [Sykes et al., Phys. Plasmas 8, 2101 (2001)]. Simulation results, obtained using either the Multi-Mode transport model (MMM95) or, alternatively, the mixed-Bohm/gyro-Bohm transport model, are compared with experimental data. In addition to the anomalous transport, neoclassical transport is included in the simulations and the ion thermal diffusivity in the inner third of the plasma is found to be predominantly neoclassical. The sawtooth oscillations in the simulations radially spread the neutral beam injection heating profiles across a broad sawtooth mixing region. The broad sawtooth oscillations also flatten the central temperature and electron density profiles. Simulation results for the electron temperature and density profiles are compared with experimental data to test the applicability of these models and the BALDUR integrated modeling code in the limit of low aspect ratio toroidal plasmas

Qualitative and Quantitative Integrated Modeling for Stochastic Simulation and Optimization

Directory of Open Access Journals (Sweden)

Xuefeng Yan

2013-01-01

Full Text Available The simulation and optimization of an actual physics system are usually constructed based on the stochastic models, which have both qualitative and quantitative characteristics inherently. Most modeling specifications and frameworks find it difficult to describe the qualitative model directly. In order to deal with the expert knowledge, uncertain reasoning, and other qualitative information, a qualitative and quantitative combined modeling specification was proposed based on a hierarchical model structure framework. The new modeling approach is based on a hierarchical model structure which includes the meta-meta model, the meta-model and the high-level model. A description logic system is defined for formal definition and verification of the new modeling specification. A stochastic defense simulation was developed to illustrate how to model the system and optimize the result. The result shows that the proposed method can describe the complex system more comprehensively, and the survival probability of the target is higher by introducing qualitative models into quantitative simulation.

Simulation modeling and analysis with Arena

CERN Document Server

Altiok, Tayfur

2007-01-01

Simulation Modeling and Analysis with Arena is a highly readable textbook which treats the essentials of the Monte Carlo discrete-event simulation methodology, and does so in the context of a popular Arena simulation environment.” It treats simulation modeling as an in-vitro laboratory that facilitates the understanding of complex systems and experimentation with what-if scenarios in order to estimate their performance metrics. The book contains chapters on the simulation modeling methodology and the underpinnings of discrete-event systems, as well as the relevant underlying probability, statistics, stochastic processes, input analysis, model validation and output analysis. All simulation-related concepts are illustrated in numerous Arena examples, encompassing production lines, manufacturing and inventory systems, transportation systems, and computer information systems in networked settings.· Introduces the concept of discrete event Monte Carlo simulation, the most commonly used methodology for modeli...

Simulating spin models on GPU

Science.gov (United States)

Weigel, Martin

2011-09-01

Over the last couple of years it has been realized that the vast computational power of graphics processing units (GPUs) could be harvested for purposes other than the video game industry. This power, which at least nominally exceeds that of current CPUs by large factors, results from the relative simplicity of the GPU architectures as compared to CPUs, combined with a large number of parallel processing units on a single chip. To benefit from this setup for general computing purposes, the problems at hand need to be prepared in a way to profit from the inherent parallelism and hierarchical structure of memory accesses. In this contribution I discuss the performance potential for simulating spin models, such as the Ising model, on GPU as compared to conventional simulations on CPU.

Standard for Models and Simulations

Science.gov (United States)

Steele, Martin J.

2016-01-01

This NASA Technical Standard establishes uniform practices in modeling and simulation to ensure essential requirements are applied to the design, development, and use of models and simulations (MS), while ensuring acceptance criteria are defined by the program project and approved by the responsible Technical Authority. It also provides an approved set of requirements, recommendations, and criteria with which MS may be developed, accepted, and used in support of NASA activities. As the MS disciplines employed and application areas involved are broad, the common aspects of MS across all NASA activities are addressed. The discipline-specific details of a given MS should be obtained from relevant recommended practices. The primary purpose is to reduce the risks associated with MS-influenced decisions by ensuring the complete communication of the credibility of MS results.

Normal Brain-Skull Development with Hybrid Deformable VR Models Simulation.

Science.gov (United States)

Jin, Jing; De Ribaupierre, Sandrine; Eagleson, Roy

2016-01-01

This paper describes a simulation framework for a clinical application involving skull-brain co-development in infants, leading to a platform for craniosynostosis modeling. Craniosynostosis occurs when one or more sutures are fused early in life, resulting in an abnormal skull shape. Surgery is required to reopen the suture and reduce intracranial pressure, but is difficult without any predictive model to assist surgical planning. We aim to study normal brain-skull growth by computer simulation, which requires a head model and appropriate mathematical methods for brain and skull growth respectively. On the basis of our previous model, we further specified suture model into fibrous and cartilaginous sutures and develop algorithm for skull extension. We evaluate the resulting simulation by comparison with datasets of cases and normal growth.

Modelling and simulating fire tube boiler performance

DEFF Research Database (Denmark)

Sørensen, K.; Condra, T.; Houbak, Niels

2003-01-01

A model for a flue gas boiler covering the flue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been defined for the furnace, the convection zone (split in 2......: a zone submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic-Equation system (DAE). Subsequently Mat......Lab/Simulink has been applied for carrying out the simulations. To be able to verify the simulated results experiments has been carried out on a full scale boiler plant....

Development of the Transport Class Model (TCM) Aircraft Simulation From a Sub-Scale Generic Transport Model (GTM) Simulation

Science.gov (United States)

Hueschen, Richard M.

2011-01-01

A six degree-of-freedom, flat-earth dynamics, non-linear, and non-proprietary aircraft simulation was developed that is representative of a generic mid-sized twin-jet transport aircraft. The simulation was developed from a non-proprietary, publicly available, subscale twin-jet transport aircraft simulation using scaling relationships and a modified aerodynamic database. The simulation has an extended aerodynamics database with aero data outside the normal transport-operating envelope (large angle-of-attack and sideslip values). The simulation has representative transport aircraft surface actuator models with variable rate-limits and generally fixed position limits. The simulation contains a generic 40,000 lb sea level thrust engine model. The engine model is a first order dynamic model with a variable time constant that changes according to simulation conditions. The simulation provides a means for interfacing a flight control system to use the simulation sensor variables and to command the surface actuators and throttle position of the engine model.

Modeling, simulation, and experiments of coating growth on nanofibers

International Nuclear Information System (INIS)

Clemons, C. B.; Hamrick, P.; Heminger, J.; Kreider, K. L.; Young, G. W.; Buldum, A.; Evans, E.; Zhang, G.

2008-01-01

This work is a comparison of modeling and simulation results with experiments for an integrated experimental/modeling investigation of a procedure to coat nanofibers and core-clad nanostructures with thin film materials using plasma enhanced physical vapor deposition. In the experimental effort, electrospun polymer nanofibers are coated with metallic materials under different operating conditions to observe changes in the coating morphology. The modeling effort focuses on linking simple models at the reactor level, nanofiber level and atomic level to form a comprehensive model. The comprehensive model leads to the definition of an evolution equation for the coating free surface around an isolated nanofiber. This evolution equation was previously derived and solved under conditions of a nearly circular coating, with a concentration field that was only radially dependent and that was independent of the location of the coating free surface. These assumptions permitted the development of analytical expressions for the concentration field. The present work does not impose the above-mentioned conditions and considers numerical simulations of the concentration field that couple with level set simulations of the evolution equation for the coating free surface. Further, the cases of coating an isolated fiber as well as a multiple fiber mat are considered. Simulation results are compared with experimental results as the reactor pressure and power, as well as the nanofiber mat porosity, are varied

Modeling and simulation of chillers with Dymola/Modelica; Modellierung und Simulation von Kaeltemaschinen mit Dymola/Modelica

Energy Technology Data Exchange (ETDEWEB)

Rettich, Daniel [Hochschule Biberach (Germany). Inst. fuer Gebaeude- und Energiesysteme (IGE)

2012-07-01

Within the contribution under consideration, a chiller was modeled and simulated with the program package Dymola / Modelica using the TIL Toolbox. An existing refrigeration technology test bench at the University of Biberach (Federal Republic of Germany) serves as a reference for the chiller illustrated in the simulation. The aim of the simulation is the future use of the models in a hardware-in-the-Loop (HIL) test bench in order to test different controllers with respect to their function and logic under identical framework conditions. Furthermore, the determination of the energy efficiency according to the regulation VDMA 24247 is in the foreground at the test bench as well as within the simulation. Following the final completion of the test bench, the models are validated against the test bench, and the model of the refrigerator will be connected to a detailed space model. Individual models were taken from the TIL toolbox, adapted for the application and parameterized with the design values of the laboratory chiller. Modifications to the TIL models were necessary in order to reflect the dynamic effects of the chiller in detail. For this purpose, investigations on indicators of the various dynamic components were employed. Subsequently to the modeling, each model was tested on the bases of design values and documents of the manufacturer. First simulation studies showed that the simulation in Dymola including the developed models provide plausible results. In the course of the modeling and parameterization of these modified models a component library was developed. Different models for future simulation studies can be extracted.

A High-Speed Train Operation Plan Inspection Simulation Model

Directory of Open Access Journals (Sweden)

Yang Rui

2018-01-01

Full Text Available We developed a train operation simulation tool to inspect a train operation plan. In applying an improved Petri Net, the train was regarded as a token, and the line and station were regarded as places, respectively, in accordance with the high-speed train operation characteristics and network function. Location change and running information transfer of the high-speed train were realized by customizing a variety of transitions. The model was built based on the concept of component combination, considering the random disturbance in the process of train running. The simulation framework can be generated quickly and the system operation can be completed according to the different test requirements and the required network data. We tested the simulation tool when used for the real-world Wuhan to Guangzhou high-speed line. The results showed that the proposed model can be developed, the simulation results basically coincide with the objective reality, and it can not only test the feasibility of the high-speed train operation plan, but also be used as a support model to develop the simulation platform with more capabilities.

SEMI Modeling and Simulation Roadmap

Energy Technology Data Exchange (ETDEWEB)

Hermina, W.L.

2000-10-02

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.

Comparison between the performance of some KEK-klystrons and simulation results

Energy Technology Data Exchange (ETDEWEB)

Fukuda, Shigeki [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

1997-04-01

Recent developments of various klystron simulation codes have enabled us to realistically design klystrons. This paper presents various simulation results using the FCI code and the performances of tubes manufactured based on this code. Upgrading a 30-MW S-band klystron and developing a 50-MW S-band klystron for the KEKB projects are successful examples based on FCI-code predictions. Mass-productions of these tubes have already started. On the other hand, a discrepancy has been found between the FCI simulation results and the performance of real tubes. In some cases, the simulation results lead to high-efficiency results, while manufactured tubes show the usual value, or a lower value, of the efficiency. One possible cause may come from a data mismatch between the electron-gun simulation and the input data set of the FCI code for the gun region. This kind of discrepancy has been observed in 30-MW S-band pulsed tubes, sub-booster pulsed tubes and L-band high-duty pulsed klystrons. Sometimes, JPNDSK (one-dimensional disk-model code) gives similar results. Some examples using the FCI code are given in this article. An Arsenal-MSU code could be applied to the 50-MW klystron under collaboration with Moscow State University; a good agreement has been found between the prediction of the code and performance. (author)

APROS 3-D core models for simulators and plant analyzers

International Nuclear Information System (INIS)

Puska, E.K.

1999-01-01

The 3-D core models of APROS simulation environment can be used in simulator and plant analyzer applications, as well as in safety analysis. The key feature of APROS models is that the same physical models can be used in all applications. For three-dimensional reactor cores the APROS models cover both quadratic BWR and PWR cores and the hexagonal lattice VVER-type cores. In APROS environment the user can select the number of flow channels in the core and either five- or six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the channel description have a decisive effect on the calculation time of the 3-D core model and thus just these selection make at present the major difference between a safety analysis model and a training simulator model. The paper presents examples of various types of 3-D LWR-type core descriptions for simulator and plant analyzer use and discusses the differences of calculation speed and physical results between a typical safety analysis model description and a real-time simulator model description in transients. (author)

Modeling and simulation of different and representative engineering problems using Network Simulation Method.

Science.gov (United States)

Sánchez-Pérez, J F; Marín, F; Morales, J L; Cánovas, M; Alhama, F

2018-01-01

Mathematical models simulating different and representative engineering problem, atomic dry friction, the moving front problems and elastic and solid mechanics are presented in the form of a set of non-linear, coupled or not coupled differential equations. For different parameters values that influence the solution, the problem is numerically solved by the network method, which provides all the variables of the problems. Although the model is extremely sensitive to the above parameters, no assumptions are considered as regards the linearization of the variables. The design of the models, which are run on standard electrical circuit simulation software, is explained in detail. The network model results are compared with common numerical methods or experimental data, published in the scientific literature, to show the reliability of the model.

Off-gas adsorption model and simulation - OSPREY

Energy Technology Data Exchange (ETDEWEB)

Rutledge, V.J. [Idaho National Laboratory, P. O. Box 1625, Idaho Falls, ID (United States)

2013-07-01

A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes is expected to provide substantial cost savings and many technical benefits. To support this capability, a modeling effort focused on the off-gas treatment system of a used nuclear fuel recycling facility is in progress. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed within Multi-physics Object Oriented Simulation Environment (MOOSE) developed at the Idaho National Laboratory (INL). Off-gas Separation and Recovery (OSPREY) models the adsorption of offgas constituents for dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions. Inputs to the model include gas composition, sorbent and column properties, equilibrium and kinetic data, and inlet conditions. The simulation outputs component concentrations along the column length as a function of time from which breakthrough data can be obtained. The breakthrough data can be used to determine bed capacity, which in turn can be used to size columns. In addition to concentration data, the model predicts temperature along the column length as a function of time and pressure drop along the column length. A description of the OSPREY model, results from krypton adsorption modeling and plans for modeling the behavior of iodine, xenon, and tritium will be discussed. (author)

New exploration on TMSR: modelling and simulation

Energy Technology Data Exchange (ETDEWEB)

Si, S.; Chen, Q.; Bei, H.; Zhao, J., E-mail: ssy@snerdi.com.cn [Shanghai Nuclear Engineering Research & Design Inst., Shanghai (China)

2015-07-01

A tightly coupled multi-physics model for MSR (Molten Salt Reactor) system involving the reactor core and the rest of the primary loop has been developed and employed in an in-house developed computer code TANG-MSR. In this paper, the computer code is used to simulate the behavior of steady state operation and transient for our redesigned TMSR. The presented simulation results demonstrate that the models employed in TANG-MSR can capture major physics phenomena in MSR and the redesigned TMSR has excellent performance of safety and sustainability. (author)

Inviscid Wall-Modeled Large Eddy Simulations for Improved Efficiency

Science.gov (United States)

Aikens, Kurt; Craft, Kyle; Redman, Andrew

2015-11-01

The accuracy of an inviscid flow assumption for wall-modeled large eddy simulations (LES) is examined because of its ability to reduce simulation costs. This assumption is not generally applicable for wall-bounded flows due to the high velocity gradients found near walls. In wall-modeled LES, however, neither the viscous near-wall region or the viscous length scales in the outer flow are resolved. Therefore, the viscous terms in the Navier-Stokes equations have little impact on the resolved flowfield. Zero pressure gradient flat plate boundary layer results are presented for both viscous and inviscid simulations using a wall model developed previously. The results are very similar and compare favorably to those from another wall model methodology and experimental data. Furthermore, the inviscid assumption reduces simulation costs by about 25% and 39% for supersonic and subsonic flows, respectively. Future research directions are discussed as are preliminary efforts to extend the wall model to include the effects of unresolved wall roughness. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant number ACI-1053575. Computational resources on TACC Stampede were provided under XSEDE allocation ENG150001.

A model for plasma discharges simulation in Tokamak devices

International Nuclear Information System (INIS)

Fonseca, Antonio M.M.; Silva, Ruy P. da; Galvao, Ricardo M.O.; Kusnetzov, Yuri; Nascimento, I.C.; Cuevas, Nelson

2001-01-01

In this work, a 'zero-dimensional' model for simulation of discharges in Tokamak machine is presented. The model allows the calculation of the time profiles of important parameters of the discharge. The model was applied to the TCABR Tokamak to study the influence of parameters and physical processes during the discharges. Basically it is constituted of five differential equations: two related to the primary and secondary circuits of the ohmic heating transformer and the other three conservation equations of energy, charge and neutral particles. From the physical model, a computer program has been built with the objective of obtaining the time profiles of plasma current, the current in the primary of the ohmic heating transformer, the electronic temperature, the electronic density and the neutral particle density. It was also possible, with the model, to simulate the effects of gas puffing during the shot. The results of the simulation were compared with the experimental results obtained in the TCABR Tokamak, using hydrogen gas

Simulation Modeling of Software Development Processes

Science.gov (United States)

Calavaro, G. F.; Basili, V. R.; Iazeolla, G.

1996-01-01

A simulation modeling approach is proposed for the prediction of software process productivity indices, such as cost and time-to-market, and the sensitivity analysis of such indices to changes in the organization parameters and user requirements. The approach uses a timed Petri Net and Object Oriented top-down model specification. Results demonstrate the model representativeness, and its usefulness in verifying process conformance to expectations, and in performing continuous process improvement and optimization.

Modeling and Simulation of Claus Unit Reaction Furnace

Directory of Open Access Journals (Sweden)

Maryam Pahlavan

2016-01-01

Full Text Available Reaction furnace is the most important part of the Claus sulfur recovery unit and its performance has a significant impact on the process efficiency. Too many reactions happen in the furnace and their kinetics and mechanisms are not completely understood; therefore, modeling reaction furnace is difficult and several works have been carried out on in this regard so far. Equilibrium models are commonly used to simulate the furnace, but the related literature states that the outlet of furnace is not in equilibrium and the furnace reactions are controlled by kinetic laws; therefore, in this study, the reaction furnace is simulated by a kinetic model. The predicted outlet temperature and concentrations by this model are compared with experimental data published in the literature and the data obtained by PROMAX V2.0 simulator. The results show that the accuracy of the proposed kinetic model and PROMAX simulator is almost similar, but the kinetic model used in this paper has two importance abilities. Firstly, it is a distributed model and can be used to obtain the temperature and concentration profiles along the furnace. Secondly, it is a dynamic model and can be used for analyzing the transient behavior and designing the control system.

VHDL-AMS modelling and simulation of a planar electrostatic micromotor

Science.gov (United States)

Endemaño, A.; Fourniols, J. Y.; Camon, H.; Marchese, A.; Muratet, S.; Bony, F.; Dunnigan, M.; Desmulliez, M. P. Y.; Overton, G.

2003-09-01

System level simulation results of a planar electrostatic micromotor, based on analytical models of the static and dynamic torque behaviours, are presented. A planar variable capacitance (VC) electrostatic micromotor designed, fabricated and tested at LAAS (Toulouse) in 1995 is simulated using the high level language VHDL-AMS (VHSIC (very high speed integrated circuits) hardware description language-analog mixed signal). The analytical torque model is obtained by first calculating the overlaps and capacitances between different electrodes based on a conformal mapping transformation. Capacitance values in the order of 10-16 F and torque values in the order of 10-11 N m have been calculated in agreement with previous measurements and simulations from this type of motor. A dynamic model has been developed for the motor by calculating the inertia coefficient and estimating the friction-coefficient-based values calculated previously for other similar devices. Starting voltage results obtained from experimental measurement are in good agreement with our proposed simulation model. Simulation results of starting voltage values, step response, switching response and continuous operation of the micromotor, based on the dynamic model of the torque, are also presented. Four VHDL-AMS blocks were created, validated and simulated for power supply, excitation control, micromotor torque creation and micromotor dynamics. These blocks can be considered as the initial phase towards the creation of intellectual property (IP) blocks for microsystems in general and electrostatic micromotors in particular.

Modeling Of A Reactive Distillation Column: Methyl Tertiary Butyl Ether (Mtbe Simulation Studies

Directory of Open Access Journals (Sweden)

Ismail Mohd Saaid Abdul Rahman Mohamed and Subhash Bhatia

2012-10-01

Full Text Available A process simulation stage-wise reactive distillation column model formulated from equilibrium stage theory was developed. The algorithm for solving mathematical model represented by sets of differential-algebraic equations was based on relaxation method. Numerical integration scheme based on backward differentiation formula was selected for solving the stiffness of differential-algebraic equations. Simulations were performed on a personal computer (PC Pentium processor through a developed computer program using FORTRAN90 programming language. The proposed model was validated by comparing the simulated results with the published simulation results and with the pilot plant data from the literature. The model was capable of predicting high isobutene conversion for heterogeneous system, as desirable in industrial MTBE production process. The comparisons on temperature profiles, liquid composition profile and operating conditions of reactive distillation column also showed promising results. Therefore the proposed model can be used as a tool for the development and simulation of reactive distillation column.Keywords: Modeling, simulation, reactive distillation, relaxation method, equilibrium stage, heterogeneous, MTBE

Implementation of virtual models from sheet metal forming simulation into physical 3D colour models using 3D printing

Science.gov (United States)

Junk, S.

2016-08-01

Today the methods of numerical simulation of sheet metal forming offer a great diversity of possibilities for optimization in product development and in process design. However, the results from simulation are only available as virtual models. Because there are any forming tools available during the early stages of product development, physical models that could serve to represent the virtual results are therefore lacking. Physical 3D-models can be created using 3D-printing and serve as an illustration and present a better understanding of the simulation results. In this way, the results from the simulation can be made more “comprehensible” within a development team. This paper presents the possibilities of 3D-colour printing with particular consideration of the requirements regarding the implementation of sheet metal forming simulation. Using concrete examples of sheet metal forming, the manufacturing of 3D colour models will be expounded upon on the basis of simulation results.

An Individual-based Probabilistic Model for Fish Stock Simulation

Directory of Open Access Journals (Sweden)

Federico Buti

2010-08-01

Full Text Available We define an individual-based probabilistic model of a sole (Solea solea behaviour. The individual model is given in terms of an Extended Probabilistic Discrete Timed Automaton (EPDTA, a new formalism that is introduced in the paper and that is shown to be interpretable as a Markov decision process. A given EPDTA model can be probabilistically model-checked by giving a suitable translation into syntax accepted by existing model-checkers. In order to simulate the dynamics of a given population of soles in different environmental scenarios, an agent-based simulation environment is defined in which each agent implements the behaviour of the given EPDTA model. By varying the probabilities and the characteristic functions embedded in the EPDTA model it is possible to represent different scenarios and to tune the model itself by comparing the results of the simulations with real data about the sole stock in the North Adriatic sea, available from the recent project SoleMon. The simulator is presented and made available for its adaptation to other species.

Landscape Modelling and Simulation Using Spatial Data

Directory of Open Access Journals (Sweden)

Amjed Naser Mohsin AL-Hameedawi

2017-08-01

Full Text Available In this paper a procedure was performed for engendering spatial model of landscape acclimated to reality simulation. This procedure based on combining spatial data and field measurements with computer graphics reproduced using Blender software. Thereafter that we are possible to form a 3D simulation based on VIS ALL packages. The objective was to make a model utilising GIS, including inputs to the feature attribute data. The objective of these efforts concentrated on coordinating a tolerable spatial prototype, circumscribing facilitation scheme and outlining the intended framework. Thus; the eventual result was utilized in simulation form. The performed procedure contains not only data gathering, fieldwork and paradigm providing, but extended to supply a new method necessary to provide the respective 3D simulation mapping production, which authorises the decision makers as well as investors to achieve permanent acceptance an independent navigation system for Geoscience applications.

Computational model to simulate the interplay effect in dynamic IMRT delivery

International Nuclear Information System (INIS)

Yoganathan, S A; Maria Das, K J; Kumar, Shaleen

2014-01-01

The purpose of this study was to develop and experimentally verify a patient specific model for simulating the interplay effect in a DMLC based IMRT delivery. A computational model was developed using MATLAB program to incorporate the interplay effect in a 2D beams eye view fluence of dynamic IMRT fields. To simulate interplay effect, the model requires two inputs: IMRT field (DMLC file with dose rate and MU) and the patient specific respiratory motion. The interplay between the DMLC leaf motion and target was simulated for three lung patients. The target trajectory data was acquired using RPM system during the treatment simulation. The model was verified experimentally for the same patients using Imatrix 2D array device placed over QUASAR motion platform in CL2100 linac. The simulated fluences and measured fluences were compared with the TPS generated static fluence (no motion) using an in-house developed gamma evaluation program (2%/2mm). The simulated results were well within agreement with the measured. Comparison of the simulated and measured fluences with the TPS static fluence resulted 55.3% and 58.5% pixels passed the gamma criteria. A patient specific model was developed and validated for simulating the interplay effect in the dynamic IMRT delivery. This model can be clinically used to quantify the dosimetric uncertainty due to the interplay effect prior to the treatment delivery.

Simulation Results of Closed Loop Controlled Interline Power Flow Controller System

Directory of Open Access Journals (Sweden)

P. USHA RANI

2016-01-01

Full Text Available The Interline Power Flow Controller (IPFC is the latest generation of Flexible AC Transmission Systems (FACTS devices which can be used to control power flows of multiple transmission lines. A dispatch strategy is proposed for an IPFC operating at rated capacity, in which the power circulation between the two series converters is used as the parameter to optimize the voltage profile and power transfer. Voltage stability curves for test system are shown to illustrate the effectiveness of this proposed strategy. In this paper, a circuit model for IPFC is developed and simulation of interline power flow controller is done using the proposed circuit model. Simulation is done using MATLAB simulink and the results are presented.

Modeling, Simulation and Position Control of 3DOF Articulated Manipulator

Directory of Open Access Journals (Sweden)

Hossein Sadegh Lafmejani

2014-08-01

Full Text Available In this paper, the modeling, simulation and control of 3 degrees of freedom articulated robotic manipulator have been studied. First, we extracted kinematics and dynamics equations of the mentioned manipulator by using the Lagrange method. In order to validate the analytical model of the manipulator we compared the model simulated in the simulation environment of Matlab with the model was simulated with the SimMechanics toolbox. A sample path has been designed for analyzing the tracking subject. The system has been linearized with feedback linearization and then a PID controller was applied to track a reference trajectory. Finally, the control results have been compared with a nonlinear PID controller.

Stochastic Modelling, Analysis, and Simulations of the Solar Cycle Dynamic Process

Science.gov (United States)

Turner, Douglas C.; Ladde, Gangaram S.

2018-03-01

Analytical solutions, discretization schemes and simulation results are presented for the time delay deterministic differential equation model of the solar dynamo presented by Wilmot-Smith et al. In addition, this model is extended under stochastic Gaussian white noise parametric fluctuations. The introduction of stochastic fluctuations incorporates variables affecting the dynamo process in the solar interior, estimation error of parameters, and uncertainty of the α-effect mechanism. Simulation results are presented and analyzed to exhibit the effects of stochastic parametric volatility-dependent perturbations. The results generalize and extend the work of Hazra et al. In fact, some of these results exhibit the oscillatory dynamic behavior generated by the stochastic parametric additative perturbations in the absence of time delay. In addition, the simulation results of the modified stochastic models influence the change in behavior of the very recently developed stochastic model of Hazra et al.

New modelling strategy for IRIS dynamic response simulation

International Nuclear Information System (INIS)

Cammi, A.; Ricotti, M. E.; Casella, F.; Schiavo, F.

2004-01-01

The pressurized light water cooled, medium power (1000 MWt) IRIS (International Reactor Innovative and Secure) has been under development for four years by an international consortium of over 21 organizations from ten countries. The plant conceptual design was completed in 2001 and the preliminary design is nearing completion. The pre-application licensing process with NRC started in October, 2002 and IRIS is one of the designs considered by US utilities as part of the ESP (Early Site Permit) process. In this paper the development of an adequate modeling and simulation tool for Dynamics and Control tasks is presented. The key features of the developed simulator are: a) Modularity: the system model is built by connecting the models of its components, which are written independently of their boundary conditions; b) Openness: the code of each component model is clearly readable and close to the original equations and easily customised by the experienced user; c) Efficiency: the simulation code is fast; d) Tool support: the simulation tool is based on reliable, tested and well-documented software. To achieve these objectives, the Modelica language was used as a basis for the development of the simulator. The Modelica language is the results of recent advances in the field of object-oriented, multi-physics, dynamic system modelling. The language definition is open-source and it has already been successfully adopted in several industrial fields. To provide the required capabilities for the analysis, specific models for nuclear reactor components have been developed, to be applied for the dynamic simulation of the IRIS integral reactor, albeit keeping general validity for PWR plants. The following Modelica models have been written to satisfy the IRIS modelling requirements and are presented in this paper: neutronics point kinetic, fuel heat transfer, control rods model, including the innovative internal drive mechanism type, and a once-through type steam generator, thus

Modeling and simulation of different and representative engineering problems using Network Simulation Method

Science.gov (United States)

2018-01-01

Mathematical models simulating different and representative engineering problem, atomic dry friction, the moving front problems and elastic and solid mechanics are presented in the form of a set of non-linear, coupled or not coupled differential equations. For different parameters values that influence the solution, the problem is numerically solved by the network method, which provides all the variables of the problems. Although the model is extremely sensitive to the above parameters, no assumptions are considered as regards the linearization of the variables. The design of the models, which are run on standard electrical circuit simulation software, is explained in detail. The network model results are compared with common numerical methods or experimental data, published in the scientific literature, to show the reliability of the model. PMID:29518121

Reproducibility in Computational Neuroscience Models and Simulations

Science.gov (United States)

McDougal, Robert A.; Bulanova, Anna S.; Lytton, William W.

2016-01-01

Objective Like all scientific research, computational neuroscience research must be reproducible. Big data science, including simulation research, cannot depend exclusively on journal articles as the method to provide the sharing and transparency required for reproducibility. Methods Ensuring model reproducibility requires the use of multiple standard software practices and tools, including version control, strong commenting and documentation, and code modularity. Results Building on these standard practices, model sharing sites and tools have been developed that fit into several categories: 1. standardized neural simulators, 2. shared computational resources, 3. declarative model descriptors, ontologies and standardized annotations; 4. model sharing repositories and sharing standards. Conclusion A number of complementary innovations have been proposed to enhance sharing, transparency and reproducibility. The individual user can be encouraged to make use of version control, commenting, documentation and modularity in development of models. The community can help by requiring model sharing as a condition of publication and funding. Significance Model management will become increasingly important as multiscale models become larger, more detailed and correspondingly more difficult to manage by any single investigator or single laboratory. Additional big data management complexity will come as the models become more useful in interpreting experiments, thus increasing the need to ensure clear alignment between modeling data, both parameters and results, and experiment. PMID:27046845

TMS modeling toolbox for realistic simulation.

Science.gov (United States)

Cho, Young Sun; Suh, Hyun Sang; Lee, Won Hee; Kim, Tae-Seong

2010-01-01

Transcranial magnetic stimulation (TMS) is a technique for brain stimulation using rapidly changing magnetic fields generated by coils. It has been established as an effective stimulation technique to treat patients suffering from damaged brain functions. Although TMS is known to be painless and noninvasive, it can also be harmful to the brain by incorrect focusing and excessive stimulation which might result in seizure. Therefore there is ongoing research effort to elucidate and better understand the effect and mechanism of TMS. Lately Boundary element method (BEM) and Finite element method (FEM) have been used to simulate the electromagnetic phenomenon of TMS. However, there is a lack of general tools to generate the models of TMS due to some difficulties in realistic modeling of the human head and TMS coils. In this study, we have developed a toolbox through which one can generate high-resolution FE TMS models. The toolbox allows creating FE models of the head with isotropic and anisotropic electrical conductivities in five different tissues of the head and the coils in 3D. The generated TMS model is importable to FE software packages such as ANSYS for further and efficient electromagnetic analysis. We present a set of demonstrative results of realistic simulation of TMS with our toolbox.

Mesoscale meteorological model based on radioactive explosion cloud simulation

International Nuclear Information System (INIS)

Zheng Yi; Zhang Yan; Ying Chuntong

2008-01-01

In order to simulate nuclear explosion and dirty bomb radioactive cloud movement and concentration distribution, mesoscale meteorological model RAMS was used. Particles-size, size-active distribution and gravitational fallout in the cloud were considered. The results show that the model can simulate the 'mushroom' clouds of explosion. Three-dimension fluid field and radioactive concentration field were received. (authors)

The effect of bathymetric filtering on nearshore process model results

Science.gov (United States)

Plant, N.G.; Edwards, K.L.; Kaihatu, J.M.; Veeramony, J.; Hsu, L.; Holland, K.T.

2009-01-01

Nearshore wave and flow model results are shown to exhibit a strong sensitivity to the resolution of the input bathymetry. In this analysis, bathymetric resolution was varied by applying smoothing filters to high-resolution survey data to produce a number of bathymetric grid surfaces. We demonstrate that the sensitivity of model-predicted wave height and flow to variations in bathymetric resolution had different characteristics. Wave height predictions were most sensitive to resolution of cross-shore variability associated with the structure of nearshore sandbars. Flow predictions were most sensitive to the resolution of intermediate scale alongshore variability associated with the prominent sandbar rhythmicity. Flow sensitivity increased in cases where a sandbar was closer to shore and shallower. Perhaps the most surprising implication of these results is that the interpolation and smoothing of bathymetric data could be optimized differently for the wave and flow models. We show that errors between observed and modeled flow and wave heights are well predicted by comparing model simulation results using progressively filtered bathymetry to results from the highest resolution simulation. The damage done by over smoothing or inadequate sampling can therefore be estimated using model simulations. We conclude that the ability to quantify prediction errors will be useful for supporting future data assimilation efforts that require this information.

A simulation model for material accounting systems

International Nuclear Information System (INIS)

Coulter, C.A.; Thomas, K.E.

1987-01-01

A general-purpose model that was developed to simulate the operation of a chemical processing facility for nuclear materials has been extended to describe material measurement and accounting procedures as well. The model now provides descriptors for material balance areas, a large class of measurement instrument types and their associated measurement errors for various classes of materials, the measurement instruments themselves with their individual calibration schedules, and material balance closures. Delayed receipt of measurement results (as for off-line analytical chemistry assay), with interim use of a provisional measurement value, can be accurately represented. The simulation model can be used to estimate inventory difference variances for processing areas that do not operate at steady state, to evaluate the timeliness of measurement information, to determine process impacts of measurement requirements, and to evaluate the effectiveness of diversion-detection algorithms. Such information is usually difficult to obtain by other means. Use of the measurement simulation model is illustrated by applying it to estimate inventory difference variances for two material balance area structures of a fictitious nuclear material processing line

Stochastic models: theory and simulation.

Energy Technology Data Exchange (ETDEWEB)

Field, Richard V., Jr.

2008-03-01

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.

Effect of land model ensemble versus coupled model ensemble on the simulation of precipitation climatology and variability

Science.gov (United States)

Wei, Jiangfeng; Dirmeyer, Paul A.; Yang, Zong-Liang; Chen, Haishan

2017-10-01

Through a series of model simulations with an atmospheric general circulation model coupled to three different land surface models, this study investigates the impacts of land model ensembles and coupled model ensemble on precipitation simulation. It is found that coupling an ensemble of land models to an atmospheric model has a very minor impact on the improvement of precipitation climatology and variability, but a simple ensemble average of the precipitation from three individually coupled land-atmosphere models produces better results, especially for precipitation variability. The generally weak impact of land processes on precipitation should be the main reason that the land model ensembles do not improve precipitation simulation. However, if there are big biases in the land surface model or land surface data set, correcting them could improve the simulated climate, especially for well-constrained regional climate simulations.

The invaluable benefits of modeling and simulation in our lives

Energy Technology Data Exchange (ETDEWEB)

Lorencez, C., E-mail: carlos.lorencez@opg.com [Ontario Power Generation, Nuclear Safety Div., Pickering, Ontario (Canada)

2015-07-01

'Full text:' In general terms, we associate the words 'modeling and simulation' with semi-ideal mathematical models reproducing complex Engineering problems. However, the use of modeling and simulation is much more extensive than that: it is applied on a daily basis in almost every front of Science, from sociology and biology to climate change, medicine, robotics, war strategies, etc. It is also being applied by our frontal lobe when we make decisions. The results of these exercises on modeling and simulation have had invaluable benefits on our well being, and we are just at the beginning. (author)

The invaluable benefits of modeling and simulation in our lives

International Nuclear Information System (INIS)

Lorencez, C.

2015-01-01

'Full text:' In general terms, we associate the words 'modeling and simulation' with semi-ideal mathematical models reproducing complex Engineering problems. However, the use of modeling and simulation is much more extensive than that: it is applied on a daily basis in almost every front of Science, from sociology and biology to climate change, medicine, robotics, war strategies, etc. It is also being applied by our frontal lobe when we make decisions. The results of these exercises on modeling and simulation have had invaluable benefits on our well being, and we are just at the beginning. (author)

CaliBayes and BASIS: integrated tools for the calibration, simulation and storage of biological simulation models.

Science.gov (United States)

Chen, Yuhui; Lawless, Conor; Gillespie, Colin S; Wu, Jake; Boys, Richard J; Wilkinson, Darren J

2010-05-01

Dynamic simulation modelling of complex biological processes forms the backbone of systems biology. Discrete stochastic models are particularly appropriate for describing sub-cellular molecular interactions, especially when critical molecular species are thought to be present at low copy-numbers. For example, these stochastic effects play an important role in models of human ageing, where ageing results from the long-term accumulation of random damage at various biological scales. Unfortunately, realistic stochastic simulation of discrete biological processes is highly computationally intensive, requiring specialist hardware, and can benefit greatly from parallel and distributed approaches to computation and analysis. For these reasons, we have developed the BASIS system for the simulation and storage of stochastic SBML models together with associated simulation results. This system is exposed as a set of web services to allow users to incorporate its simulation tools into their workflows. Parameter inference for stochastic models is also difficult and computationally expensive. The CaliBayes system provides a set of web services (together with an R package for consuming these and formatting data) which addresses this problem for SBML models. It uses a sequential Bayesian MCMC method, which is powerful and flexible, providing very rich information. However this approach is exceptionally computationally intensive and requires the use of a carefully designed architecture. Again, these tools are exposed as web services to allow users to take advantage of this system. In this article, we describe these two systems and demonstrate their integrated use with an example workflow to estimate the parameters of a simple model of Saccharomyces cerevisiae growth on agar plates.

Modeling and simulation of Si crystal growth from melt

Energy Technology Data Exchange (ETDEWEB)

Liu, Lijun; Liu, Xin; Li, Zaoyang [National Engineering Research Center for Fluid Machinery and Compressors, School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Miyazawa, Hiroaki; Nakano, Satoshi; Kakimoto, Koichi [Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580 (Japan)

2009-07-01

A numerical simulator was developed with a global model of heat transfer for any crystal growth taking place at high temperature. Convective, conductive and radiative heat transfers in the furnace are solved together in a conjugated way by a finite volume method. A three-dimensional (3D) global model was especially developed for simulation of heat transfer in any crystal growth with 3D features. The model enables 3D global simulation be conducted with moderate requirement of computer resources. The application of this numerical simulator to a CZ growth and a directional solidification process for Si crystals, the two major production methods for crystalline Si for solar cells, was introduced. Some typical results were presented, showing the importance and effectiveness of numerical simulation in analyzing and improving these kinds of Si crystal growth processes from melt. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Simulation Model of a Transient

DEFF Research Database (Denmark)

Jauch, Clemens; Sørensen, Poul; Bak-Jensen, Birgitte

2005-01-01

This paper describes the simulation model of a controller that enables an active-stall wind turbine to ride through transient faults. The simulated wind turbine is connected to a simple model of a power system. Certain fault scenarios are specified and the turbine shall be able to sustain operati...

Evaluation of articulation simulation system using artificial maxillectomy models.

Science.gov (United States)

Elbashti, M E; Hattori, M; Sumita, Y I; Taniguchi, H

2015-09-01

Acoustic evaluation is valuable for guiding the treatment of maxillofacial defects and determining the effectiveness of rehabilitation with an obturator prosthesis. Model simulations are important in terms of pre-surgical planning and pre- and post-operative speech function. This study aimed to evaluate the acoustic characteristics of voice generated by an articulation simulation system using a vocal tract model with or without artificial maxillectomy defects. More specifically, we aimed to establish a speech simulation system for maxillectomy defect models that both surgeons and maxillofacial prosthodontists can use in guiding treatment planning. Artificially simulated maxillectomy defects were prepared according to Aramany's classification (Classes I-VI) in a three-dimensional vocal tract plaster model of a subject uttering the vowel /a/. Formant and nasalance acoustic data were analysed using Computerized Speech Lab and the Nasometer, respectively. Formants and nasalance of simulated /a/ sounds were successfully detected and analysed. Values of Formants 1 and 2 for the non-defect model were 675.43 and 976.64 Hz, respectively. Median values of Formants 1 and 2 for the defect models were 634.36 and 1026.84 Hz, respectively. Nasalance was 11% in the non-defect model, whereas median nasalance was 28% in the defect models. The results suggest that an articulation simulation system can be used to help surgeons and maxillofacial prosthodontists to plan post-surgical defects that will be facilitate maxillofacial rehabilitation. © 2015 John Wiley & Sons Ltd.

NRTA simulation by modeling PFPF

International Nuclear Information System (INIS)

Asano, Takashi; Fujiwara, Shigeo; Takahashi, Saburo; Shibata, Junichi; Totsu, Noriko

2003-01-01

In PFPF, NRTA system has been applied since 1991. It has been confirmed by evaluating facility material accountancy data provided from operator in each IIV that a significant MUF was not generated. In case of throughput of PFPF scale, MUF can be evaluated with a sufficient detection probability by the present NRTA evaluation manner. However, by increasing of throughput, the uncertainty of material accountancy will increase, and the detection probability will decline. The relationship between increasing of throughput and declining of detection probability and the maximum throughput upon application of following measures with a sufficient detection probability were evaluated by simulation of NRTA system. This simulation was performed by modeling of PFPF. Measures for increasing detection probability are shown as follows. Shortening of the evaluation interval. Segmentation of evaluation area. This report shows the results of these simulations. (author)

CFD simulations in the nuclear containment using the DES turbulence models

International Nuclear Information System (INIS)

Ding, Peng; Chen, Meilan; Li, Wanai; Liu, Yulan; Wang, Biao

2015-01-01

Highlights: • The k-ε based DES model is used in the nuclear containment simulation. • The comparison of results between different turbulent models is obtained. • The superiority of DES models is analyzed. • The computational efficiency with the DES turbulence models is explained. - Abstract: Different species of gases would be released into the containment and cause unpredicted disasters during the nuclear severe accidents. It is important to accurately predict the transportation and stratification phenomena of these gas mixtures. CFD simulations of these thermal hydraulic issues in nuclear containment are investigated in this paper. The main work is to study the influence of turbulence model on the calculation of gas transportation and heat transfer. The k-ε based DES and other frequently used turbulence models are used in the steam and helium release simulation in THAI series experiment. This paper will show the superiority of the DES turbulence model in terms of computational efficiency and accuracy with the experimental results, and analyze the necessities of DES model to simulate the large-scale containment flows with both laminar and turbulence regions

CFD simulations in the nuclear containment using the DES turbulence models

Energy Technology Data Exchange (ETDEWEB)

Ding, Peng [School of Engineering, Sun Yat-Sen University, Guangzhou (China); Chen, Meilan [China Nuclear Power Technology Research Institute, Shenzhen (China); Li, Wanai, E-mail: liwai@mail.sysu.edu.cn [Sino-French Institute of Nuclear Engineering & Technology, Sun Yat-Sen University, Guangzhou (China); Liu, Yulan [School of Engineering, Sun Yat-Sen University, Guangzhou (China); Wang, Biao [Sino-French Institute of Nuclear Engineering & Technology, Sun Yat-Sen University, Guangzhou (China)

2015-06-15

Highlights: • The k-ε based DES model is used in the nuclear containment simulation. • The comparison of results between different turbulent models is obtained. • The superiority of DES models is analyzed. • The computational efficiency with the DES turbulence models is explained. - Abstract: Different species of gases would be released into the containment and cause unpredicted disasters during the nuclear severe accidents. It is important to accurately predict the transportation and stratification phenomena of these gas mixtures. CFD simulations of these thermal hydraulic issues in nuclear containment are investigated in this paper. The main work is to study the influence of turbulence model on the calculation of gas transportation and heat transfer. The k-ε based DES and other frequently used turbulence models are used in the steam and helium release simulation in THAI series experiment. This paper will show the superiority of the DES turbulence model in terms of computational efficiency and accuracy with the experimental results, and analyze the necessities of DES model to simulate the large-scale containment flows with both laminar and turbulence regions.

TRSM-a thermal-hydraulic real-time simulation model for PWR

International Nuclear Information System (INIS)

Zhou Weichang

1997-01-01

TRSM (a Thermal-hydraulic Real-time Simulation Model) has been developed for PWR real-time simulation and best-estimate prediction of normal operating and abnormal accident conditions. It is a non-equilibrium two phase flow thermal-hydraulic model based on five basic conservation equations. A drift flux model is used to account for the unequal velocities of liquid and gaseous mixture, with or without the presence of the noncondensibles. Critical flow models are applied for break flow and valve flow calculations. A 5-regime two phase heat convection model is applied for clad-to-coolant as well as fluid-to-tubing heat transfer. A rigorous reactor coolant pump model is used to calculate the pressure drop and rise for the suction and discharge ends with complete pump characteristics curves included. The TRSM model has been adapted in the full-scale training simulator of Qinshan Nuclear Power Plant 300 MW unit to simulate the thermal-hydraulic performance of the NSSS. The simulation results of a cold leg LOCA and a steam generator tube rupture (SGTR) accident are presented

Semiconductor device models for circuit simulation power electronics; Modeles de composants semiconducteurs pour la simulation des circuits en electronique de puissance

Energy Technology Data Exchange (ETDEWEB)

Berraies, M.O.

1998-09-10

In this thesis, an alternative strategy based on a regional approach to modeling and a new partition of the model library in the simulation is proposed. The main objective is to substitute for the usual concept of `one device, on model` that of an adaptable assembly of a limited number of submodels associated with well-identified regions of semiconductor structures. In other words, the library will only contain the primitive building-blocks of the power device models. This strategy guarantees the compatibility of the various semiconductor models in terms of physical concepts, validity domain, accuracy, homogeneity of parameter identification procedures, similarly of implementation in the simulator. This approach has been applied to PIN diodes and IGBTs for experimental validation. The next step consisted on the simulation of circuit involving several interacting devices. A simple IGBT/PIN diode chopper cell has been chosen. The results obtained compare well with experiment. This demonstrates the consistency of the proposed approach. (author) 43 refs.

A VRLA battery simulation model

International Nuclear Information System (INIS)

Pascoe, Phillip E.; Anbuky, Adnan H.

2004-01-01

A valve regulated lead acid (VRLA) battery simulation model is an invaluable tool for the standby power system engineer. The obvious use for such a model is to allow the assessment of battery performance. This may involve determining the influence of cells suffering from state of health (SOH) degradation on the performance of the entire string, or the running of test scenarios to ascertain the most suitable battery size for the application. In addition, it enables the engineer to assess the performance of the overall power system. This includes, for example, running test scenarios to determine the benefits of various load shedding schemes. It also allows the assessment of other power system components, either for determining their requirements and/or vulnerabilities. Finally, a VRLA battery simulation model is vital as a stand alone tool for educational purposes. Despite the fundamentals of the VRLA battery having been established for over 100 years, its operating behaviour is often poorly understood. An accurate simulation model enables the engineer to gain a better understanding of VRLA battery behaviour. A system level multipurpose VRLA battery simulation model is presented. It allows an arbitrary battery (capacity, SOH, number of cells and number of strings) to be simulated under arbitrary operating conditions (discharge rate, ambient temperature, end voltage, charge rate and initial state of charge). The model accurately reflects the VRLA battery discharge and recharge behaviour. This includes the complex start of discharge region known as the coup de fouet

Simulation Modelling and Strategic Change: Creating the Sustainable Enterprise

Directory of Open Access Journals (Sweden)

Patrick Dawson

2010-01-01

Full Text Available This paper highlights the benefits of using discrete event simulation models for developing change management frameworks which facilitate productivity and environmental improvements in order to create a sustainable enterprise. There is an increasing need for organisations to be more socially and environmentally responsible, however these objectives cannot be realised in isolation of the strategic, operations and business objectives of the enterprise. Discrete Event Simulation models facilitate a multidimensional approach to enterprise modelling which can integrate operations and strategic considerations with environmental and social issues. Moreover these models can provide a dynamic roadmap for implementing a change strategy for realising the optimal conditions for operational and environmental performance. It is important to note that the nature of change is itself dynamic and that simulation models are capable of characterising the dynamics of the change process. The paper argues that incorporating social and environmental challenges into a strategic business model for an enterprise can result in improved profits and long term viability and that a multidimensional simulation approach can support decision making throughout the change process to more effectively achieve these goals.

Modeling and simulation for micro DC motor based on simulink

Science.gov (United States)

Shen, Hanxin; Lei, Qiao; Chen, Wenxiang

2017-09-01

The micro DC motor has a large market demand but there is a lack of theoretical research for it. Through detailed analysis of the commutation process of micro DC motor commutator, based on micro DC motor electromagnetic torque equation and mechanical torque equation, with the help of Simulink toolkit, a triangle connection micro DC motor simulation model is established. By using the model, a sample micro DC motor are simulated, and an experimental measurements has been carried on the sample micro DC motor. It is found that the simulation results are consistent with theoretical analysis and experimental results.

Noise Simulations of the High-Lift Common Research Model

Science.gov (United States)

Lockard, David P.; Choudhari, Meelan M.; Vatsa, Veer N.; O'Connell, Matthew D.; Duda, Benjamin; Fares, Ehab

2017-01-01

The PowerFLOW(TradeMark) code has been used to perform numerical simulations of the high-lift version of the Common Research Model (HL-CRM) that will be used for experimental testing of airframe noise. Time-averaged surface pressure results from PowerFLOW(TradeMark) are found to be in reasonable agreement with those from steady-state computations using FUN3D. Surface pressure fluctuations are highest around the slat break and nacelle/pylon region, and synthetic array beamforming results also indicate that this region is the dominant noise source on the model. The gap between the slat and pylon on the HL-CRM is not realistic for modern aircraft, and most nacelles include a chine that is absent in the baseline model. To account for those effects, additional simulations were completed with a chine and with the slat extended into the pylon. The case with the chine was nearly identical to the baseline, and the slat extension resulted in higher surface pressure fluctuations but slightly reduced radiated noise. The full-span slat geometry without the nacelle/pylon was also simulated and found to be around 10 dB quieter than the baseline over almost the entire frequency range. The current simulations are still considered preliminary as changes in the radiated acoustics are still being observed with grid refinement, and additional simulations with finer grids are planned.

Multi-scale modelling of supercapacitors: From molecular simulations to a transmission line model

Science.gov (United States)

Pean, C.; Rotenberg, B.; Simon, P.; Salanne, M.

2016-09-01

We perform molecular dynamics simulations of a typical nanoporous-carbon based supercapacitor. The organic electrolyte consists in 1-ethyl-3-methylimidazolium and hexafluorophosphate ions dissolved in acetonitrile. We simulate systems at equilibrium, for various applied voltages. This allows us to determine the relevant thermodynamic (capacitance) and transport (in-pore resistivities) properties. These quantities are then injected in a transmission line model for testing its ability to predict the charging properties of the device. The results from this macroscopic model are in good agreement with non-equilibrium molecular dynamics simulations, which validates its use for interpreting electrochemical impedance experiments.

Measurement with microscopic MRI and simulation of flow in different aneurysm models

Energy Technology Data Exchange (ETDEWEB)

Edelhoff, Daniel, E-mail: daniel.edelhoff@tu-dortmund.de; Frank, Frauke; Heil, Marvin; Suter, Dieter [Experimental Physics III, TU Dortmund University, Otto-Hahn-Street 4, Dortmund 44227 (Germany); Walczak, Lars; Weichert, Frank [Computer Science VII, TU Dortmund University, Otto-Hahn-Street 16, Dortmund 44227 (Germany); Schmitz, Inge [Institute for Pathology, Ruhr Universität Bochum, Bürkle-de-la-Camp-Platz 1, Bochum 44789 (Germany)

2015-10-15

Purpose: The impact and the development of aneurysms depend to a significant degree on the exchange of liquid between the regular vessel and the pathological extension. A better understanding of this process will lead to improved prediction capabilities. The aim of the current study was to investigate fluid-exchange in aneurysm models of different complexities by combining microscopic magnetic resonance measurements with numerical simulations. In order to evaluate the accuracy and applicability of these methods, the fluid-exchange process between the unaltered vessel lumen and the aneurysm phantoms was analyzed quantitatively using high spatial resolution. Methods: Magnetic resonance flow imaging was used to visualize fluid-exchange in two different models produced with a 3D printer. One model of an aneurysm was based on histological findings. The flow distribution in the different models was measured on a microscopic scale using time of flight magnetic resonance imaging. The whole experiment was simulated using fast graphics processing unit-based numerical simulations. The obtained simulation results were compared qualitatively and quantitatively with the magnetic resonance imaging measurements, taking into account flow and spin–lattice relaxation. Results: The results of both presented methods compared well for the used aneurysm models and the chosen flow distributions. The results from the fluid-exchange analysis showed comparable characteristics concerning measurement and simulation. Similar symmetry behavior was observed. Based on these results, the amount of fluid-exchange was calculated. Depending on the geometry of the models, 7% to 45% of the liquid was exchanged per second. Conclusions: The result of the numerical simulations coincides well with the experimentally determined velocity field. The rate of fluid-exchange between vessel and aneurysm was well-predicted. Hence, the results obtained by simulation could be validated by the experiment. The

Numerical simulations of altocumulus with a cloud resolving model

Energy Technology Data Exchange (ETDEWEB)

Liu, S.; Krueger, S.K. [Univ. of Utah, Salt Lake City, UT (United States)

1996-04-01

Altocumulus and altostratus clouds together cover approximately 22% of the earth`s surface. They play an important role in the earth`s energy budget through their effect on solar and infrared radiation. However, there has been little altocumulus cloud investigation by either modelers or observational programs. Starr and Cox (SC) (1985a,b) simulated an altostratus case as part of the same study in which they modeled a thin layer of cirrus. Although this calculation was originally described as representing altostratus, it probably better represents altocumulus stratiformis. In this paper, we simulate altocumulus cloud with a cloud resolving model (CRM). We simply describe the CRM first. We calculate the same middle-level cloud case as SC to compare our results with theirs. We will look at the role of cloud-scale processes in response to large-scale forcing. We will also discuss radiative effects by simulating diurnal and nocturnal cases. Finally, we discuss the utility of a 1D model by comparing 1D simulations and 2D simulations.

Solar Deployment System (SolarDS) Model: Documentation and Sample Results

Energy Technology Data Exchange (ETDEWEB)

Denholm, P.; Drury, E.; Margolis, R.

2009-09-01

The Solar Deployment System (SolarDS) model is a bottom-up, market penetration model that simulates the potential adoption of photovoltaics (PV) on residential and commercial rooftops in the continental United States through 2030. NREL developed SolarDS to examine the market competitiveness of PV based on regional solar resources, capital costs, electricity prices, utility rate structures, and federal and local incentives. The model uses the projected financial performance of PV systems to simulate PV adoption for building types and regions then aggregates adoption to state and national levels. The main components of SolarDS include a PV performance simulator, a PV annual revenue calculator, a PV financial performance calculator, a PV market share calculator, and a regional aggregator. The model simulates a variety of installed PV capacity for a range of user-specified input parameters. PV market penetration levels from 15 to 193 GW by 2030 were simulated in preliminary model runs. SolarDS results are primarily driven by three model assumptions: (1) future PV cost reductions, (2) the maximum PV market share assumed for systems with given financial performance, and (3) PV financing parameters and policy-driven assumptions, such as the possible future cost of carbon emissions.

Managing emergency department overcrowding via ambulance diversion: A discrete event simulation model

Directory of Open Access Journals (Sweden)

Chih-Hao Lin

2015-01-01

Conclusion: An input–throughput–output simulation model is proposed for simulating ED operation. Effectiveness of several AD strategies on relieving ED overcrowding was assessed via computer simulations based on this model. By appropriate parameter settings, the model can represent medical resource providers of different scales. It is also feasible to expand the simulations to evaluate the effect of AD strategies on a community basis. The results may offer insights for making effective AD policies.

Accurate lithography simulation model based on convolutional neural networks

Science.gov (United States)

Watanabe, Yuki; Kimura, Taiki; Matsunawa, Tetsuaki; Nojima, Shigeki

2017-07-01

Lithography simulation is an essential technique for today's semiconductor manufacturing process. In order to calculate an entire chip in realistic time, compact resist model is commonly used. The model is established for faster calculation. To have accurate compact resist model, it is necessary to fix a complicated non-linear model function. However, it is difficult to decide an appropriate function manually because there are many options. This paper proposes a new compact resist model using CNN (Convolutional Neural Networks) which is one of deep learning techniques. CNN model makes it possible to determine an appropriate model function and achieve accurate simulation. Experimental results show CNN model can reduce CD prediction errors by 70% compared with the conventional model.

Evaluation of Three Models for Simulating Pesticide Runoff from Irrigated Agricultural Fields.

Science.gov (United States)

Zhang, Xuyang; Goh, Kean S

2015-11-01

Three models were evaluated for their accuracy in simulating pesticide runoff at the edge of agricultural fields: Pesticide Root Zone Model (PRZM), Root Zone Water Quality Model (RZWQM), and OpusCZ. Modeling results on runoff volume, sediment erosion, and pesticide loss were compared with measurements taken from field studies. Models were also compared on their theoretical foundations and ease of use. For runoff events generated by sprinkler irrigation and rainfall, all models performed equally well with small errors in simulating water, sediment, and pesticide runoff. The mean absolute percentage errors (MAPEs) were between 3 and 161%. For flood irrigation, OpusCZ simulated runoff and pesticide mass with the highest accuracy, followed by RZWQM and PRZM, likely owning to its unique hydrological algorithm for runoff simulations during flood irrigation. Simulation results from cold model runs by OpusCZ and RZWQM using measured values for model inputs matched closely to the observed values. The MAPE ranged from 28 to 384 and 42 to 168% for OpusCZ and RZWQM, respectively. These satisfactory model outputs showed the models' abilities in mimicking reality. Theoretical evaluations indicated that OpusCZ and RZWQM use mechanistic approaches for hydrology simulation, output data on a subdaily time-step, and were able to simulate management practices and subsurface flow via tile drainage. In contrast, PRZM operates at daily time-step and simulates surface runoff using the USDA Soil Conservation Service's curve number method. Among the three models, OpusCZ and RZWQM were suitable for simulating pesticide runoff in semiarid areas where agriculture is heavily dependent on irrigation. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Simulated CONUS Flash Flood Climatologies from Distributed Hydrologic Models

Science.gov (United States)

Flamig, Z.; Gourley, J. J.; Vergara, H. J.; Kirstetter, P. E.; Hong, Y.

2016-12-01

This study will describe a CONUS flash flood climatology created over the period from 2002 through 2011. The MRMS reanalysis precipitation dataset was used as forcing into the Ensemble Framework For Flash Flood Forecasting (EF5). This high resolution 1-sq km 5-minute dataset is ideal for simulating flash floods with a distributed hydrologic model. EF5 features multiple water balance components including SAC-SMA, CREST, and a hydrophobic model all coupled with kinematic wave routing. The EF5/SAC-SMA and EF5/CREST water balance schemes were used for the creation of dual flash flood climatologies based on the differing water balance principles. For the period from 2002 through 2011 the daily maximum streamflow, unit streamflow, and time of peak streamflow was stored along with the minimum soil moisture. These variables are used to describe the states of the soils right before a flash flood event and the peak streamflow that was simulated during the flash flood event. The results will be shown, compared and contrasted. The resulting model simulations will be verified on basins less than 1,000-sq km with USGS gauges to ensure the distributed hydrologic models are reliable. The results will also be compared spatially to Storm Data flash flood event observations to judge the degree of agreement between the simulated climatologies and observations.

NUMERICAL SIMULATION AND MODELING OF UNSTEADY FLOW ...

African Journals Online (AJOL)

2014-06-30

Jun 30, 2014 ... objective of this study is to control the simulation of unsteady flows around structures. ... Aerospace, our results were in good agreement with experimental .... Two-Equation Eddy-Viscosity Turbulence Models for Engineering.

Development and demonstration of a validation methodology for vehicle lateral dynamics simulation models

Energy Technology Data Exchange (ETDEWEB)

Kutluay, Emir

2013-02-01

In this thesis a validation methodology to be used in the assessment of the vehicle dynamics simulation models is presented. Simulation of vehicle dynamics is used to estimate the dynamic responses of existing or proposed vehicles and has a wide array of applications in the development of vehicle technologies. Although simulation environments, measurement tools and mathematical theories on vehicle dynamics are well established, the methodical link between the experimental test data and validity analysis of the simulation model is still lacking. The developed validation paradigm has a top-down approach to the problem. It is ascertained that vehicle dynamics simulation models can only be validated using test maneuvers although they are aimed for real world maneuvers. Test maneuvers are determined according to the requirements of the real event at the start of the model development project and data handling techniques, validation metrics and criteria are declared for each of the selected maneuvers. If the simulation results satisfy these criteria, then the simulation is deemed ''not invalid''. If the simulation model fails to meet the criteria, the model is deemed invalid, and model iteration should be performed. The results are analyzed to determine if the results indicate a modeling error or a modeling inadequacy; and if a conditional validity in terms of system variables can be defined. Three test cases are used to demonstrate the application of the methodology. The developed methodology successfully identified the shortcomings of the tested simulation model, and defined the limits of application. The tested simulation model is found to be acceptable but valid only in a certain dynamical range. Several insights for the deficiencies of the model are reported in the analysis but the iteration step of the methodology is not demonstrated. Utilizing the proposed methodology will help to achieve more time and cost efficient simulation projects with

Simulation results for a multirate mass transfer modell for immiscible displacement of two fluids in highly heterogeneous porous media

Science.gov (United States)

Tecklenburg, Jan; Neuweiler, Insa; Dentz, Marco; Carrera, Jesus; Geiger, Sebastian

2013-04-01

Flow processes in geotechnical applications do often take place in highly heterogeneous porous media, such as fractured rock. Since, in this type of media, classical modelling approaches are problematic, flow and transport is often modelled using multi-continua approaches. From such approaches, multirate mass transfer models (mrmt) can be derived to describe the flow and transport in the "fast" or mobile zone of the medium. The porous media is then modeled with one mobile zone and multiple immobile zones, where the immobile zones are connected to the mobile zone by single rate mass transfer. We proceed from a mrmt model for immiscible displacement of two fluids, where the Buckley-Leverett equation is expanded by a sink-source-term which is nonlocal in time. This sink-source-term models exchange with an immobile zone with mass transfer driven by capillary diffusion. This nonlinear diffusive mass transfer can be approximated for particular imbibition or drainage cases by a linear process. We present a numerical scheme for this model together with simulation results for a single fracture test case. We solve the mrmt model with the finite volume method and explicit time integration. The sink-source-term is transformed to multiple single rate mass transfer processes, as shown by Carrera et. al. (1998), to make it local in time. With numerical simulations we studied immiscible displacement in a single fracture test case. To do this we calculated the flow parameters using information about the geometry and the integral solution for two phase flow by McWorther and Sunnada (1990). Comparision to the results of the full two dimensional two phase flow model by Flemisch et. al. (2011) show good similarities of the saturation breakthrough curves. Carrera, J., Sanchez-Vila, X., Benet, I., Medina, A., Galarza, G., and Guimera, J.: On matrix diffusion: formulations, solution methods and qualitative effects, Hydrogeology Journal, 6, 178-190, 1998. Flemisch, B., Darcis, M

Moving Boudary Models for Dynamic Simulations of Two-phase Flows

DEFF Research Database (Denmark)

Jensen, Jakob Munch; Tummelscheit, H.

2002-01-01

. The Dymola Modelica translator can automatically reduce the DAE index and thus makes efficient simulation possible. Usually the flow entering a dry-expansion evaporator in a refrigeration system is two-phase, and there is thus no liquid region. The general MB model has a number of special cases where only...... model is used. The overall robustness and the simplicity of the MB model, makes it well suited for open loop as well as closed loop simulations of two-phase flows. Simulation results for an evaporator in a refrigeration system are shown. The open loop system is simulated both with the reduced MB...... but is less complex. The reduced MB-model is well suited for control purposes both for determining control parameters and for model based control strategies and examples of a controlled refrigeration system are shown. The general MB model divides the flow into three regions (liquid, two-phase and vapor...

Simulation on Poisson and negative binomial models of count road accident modeling

Science.gov (United States)

Sapuan, M. S.; Razali, A. M.; Zamzuri, Z. H.; Ibrahim, K.

2016-11-01

Accident count data have often been shown to have overdispersion. On the other hand, the data might contain zero count (excess zeros). The simulation study was conducted to create a scenarios which an accident happen in T-junction with the assumption the dependent variables of generated data follows certain distribution namely Poisson and negative binomial distribution with different sample size of n=30 to n=500. The study objective was accomplished by fitting Poisson regression, negative binomial regression and Hurdle negative binomial model to the simulated data. The model validation was compared and the simulation result shows for each different sample size, not all model fit the data nicely even though the data generated from its own distribution especially when the sample size is larger. Furthermore, the larger sample size indicates that more zeros accident count in the dataset.

Magnetosphere Modeling: From Cartoons to Simulations

Science.gov (United States)

Gombosi, T. I.

2017-12-01

Over the last half a century physics-based global computer simulations became a bridge between experiment and basic theory and now it represents the "third pillar" of geospace research. Today, many of our scientific publications utilize large-scale simulations to interpret observations, test new ideas, plan campaigns, or design new instruments. Realistic simulations of the complex Sun-Earth system have been made possible by the dramatically increased power of both computing hardware and numerical algorithms. Early magnetosphere models were based on simple E&M concepts (like the Chapman-Ferraro cavity) and hydrodynamic analogies (bow shock). At the beginning of the space age current system models were developed culminating in the sophisticated Tsyganenko-type description of the magnetic configuration. The first 3D MHD simulations of the magnetosphere were published in the early 1980s. A decade later there were several competing global models that were able to reproduce many fundamental properties of the magnetosphere. The leading models included the impact of the ionosphere by using a height-integrated electric potential description. Dynamic coupling of global and regional models started in the early 2000s by integrating a ring current and a global magnetosphere model. It has been recognized for quite some time that plasma kinetic effects play an important role. Presently, global hybrid simulations of the dynamic magnetosphere are expected to be possible on exascale supercomputers, while fully kinetic simulations with realistic mass ratios are still decades away. In the 2010s several groups started to experiment with PIC simulations embedded in large-scale 3D MHD models. Presently this integrated MHD-PIC approach is at the forefront of magnetosphere simulations and this technique is expected to lead to some important advances in our understanding of magnetosheric physics. This talk will review the evolution of magnetosphere modeling from cartoons to current systems

Context-Dependent Help for the DynaLearn Modelling and Simulation Workbench

NARCIS (Netherlands)

Beek, W.; Bredeweg, B.; Latour, S.; Biswas, G.; Bull, S.; Kay, J.; Mitrovic, A.

2011-01-01

We implemented three kinds of context-dependent help for a qualitative modelling and simulation workbench called DynaLearn. We show that it is possible to generate and select assistance knowledge based on the current model, simulation results and workbench state.

Stochastic modeling analysis and simulation

CERN Document Server

Nelson, Barry L

1995-01-01

A coherent introduction to the techniques for modeling dynamic stochastic systems, this volume also offers a guide to the mathematical, numerical, and simulation tools of systems analysis. Suitable for advanced undergraduates and graduate-level industrial engineers and management science majors, it proposes modeling systems in terms of their simulation, regardless of whether simulation is employed for analysis. Beginning with a view of the conditions that permit a mathematical-numerical analysis, the text explores Poisson and renewal processes, Markov chains in discrete and continuous time, se

Modeling and simulation of Indus-2 RF feedback control system

International Nuclear Information System (INIS)

Sharma, D.; Bagduwal, P.S.; Tiwari, N.; Lad, M.; Hannurkar, P.R.

2012-01-01

Indus-2 synchrotron radiation source has four RF stations along with their feedback control systems. For higher beam energy and current operation amplitude and phase feedback control systems of Indus-2 are being upgraded. To understand the behaviour of amplitude and phase control loop under different operating conditions, modelling and simulation of RF feedback control system is done. RF cavity baseband I/Q model has been created due to its close correspondence with actual implementation and better computational efficiency which makes the simulation faster. Correspondence between cavity baseband and RF model is confirmed by comparing their simulation results. Low Level RF (LLRF) feedback control system simulation is done using the same cavity baseband I/Q model. Error signals are intentionally generated and response of the closed loop system is observed. Simulation will help us in optimizing parameters of upgraded LLRF system for higher beam energy and current operation. (author)

Generalized math model for simulation of high-altitude balloon systems

Science.gov (United States)

Nigro, N. J.; Elkouh, A. F.; Hinton, D. E.; Yang, J. K.

1985-01-01

Balloon systems have proved to be a cost-effective means for conducting research experiments (e.g., infrared astronomy) in the earth's atmosphere. The purpose of this paper is to present a generalized mathematical model that can be used to simulate the motion of these systems once they have attained float altitude. The resulting form of the model is such that the pendulation and spin motions of the system are uncoupled and can be analyzed independently. The model is evaluated by comparing the simulation results with data obtained from an actual balloon system flown by NASA.

An accurate behavioral model for single-photon avalanche diode statistical performance simulation

Science.gov (United States)

Xu, Yue; Zhao, Tingchen; Li, Ding

2018-01-01

An accurate behavioral model is presented to simulate important statistical performance of single-photon avalanche diodes (SPADs), such as dark count and after-pulsing noise. The derived simulation model takes into account all important generation mechanisms of the two kinds of noise. For the first time, thermal agitation, trap-assisted tunneling and band-to-band tunneling mechanisms are simultaneously incorporated in the simulation model to evaluate dark count behavior of SPADs fabricated in deep sub-micron CMOS technology. Meanwhile, a complete carrier trapping and de-trapping process is considered in afterpulsing model and a simple analytical expression is derived to estimate after-pulsing probability. In particular, the key model parameters of avalanche triggering probability and electric field dependence of excess bias voltage are extracted from Geiger-mode TCAD simulation and this behavioral simulation model doesn't include any empirical parameters. The developed SPAD model is implemented in Verilog-A behavioral hardware description language and successfully operated on commercial Cadence Spectre simulator, showing good universality and compatibility. The model simulation results are in a good accordance with the test data, validating high simulation accuracy.

Climate simulations for 1880-2003 with GISS modelE

International Nuclear Information System (INIS)

Hansen, J.; Lacis, A.; Miller, R.; Schmidt, G.A.; Russell, G.; Canuto, V.; Del Genio, A.; Hall, T.; Hansen, J.; Sato, M.; Kharecha, P.; Nazarenko, L.; Aleinov, I.; Bauer, S.; Chandler, M.; Faluvegi, G.; Jonas, J.; Ruedy, R.; Lo, K.; Cheng, Y.; Lacis, A.; Schmidt, G.A.; Del Genio, A.; Miller, R.; Cairns, B.; Hall, T.; Baum, E.; Cohen, A.; Fleming, E.; Jackman, C.; Friend, A.; Kelley, M.

2007-01-01

We carry out climate simulations for 1880-2003 with GISS modelE driven by ten measured or estimated climate forcing. An ensemble of climate model runs is carried out for each forcing acting individually and for all forcing mechanisms acting together. We compare side-by-side simulated climate change for each forcing, all forcing, observations, unforced variability among model ensemble members, and, if available, observed variability. Discrepancies between observations and simulations with all forcing are due to model deficiencies, inaccurate or incomplete forcing, and imperfect observations. Although there are notable discrepancies between model and observations, the fidelity is sufficient to encourage use of the model for simulations of future climate change. By using a fixed well-documented model and accurately defining the 1880-2003 forcing, we aim to provide a benchmark against which the effect of improvements in the model, climate forcing, and observations can be tested. Principal model deficiencies include unrealistic weak tropical El Nino-like variability and a poor distribution of sea ice, with too much sea ice in the Northern Hemisphere and too little in the Southern Hemisphere. Greatest uncertainties in the forcing are the temporal and spatial variations of anthropogenic aerosols and their indirect effects on clouds. (authors)

FASTBUS simulation models in VHDL

International Nuclear Information System (INIS)

Appelquist, G.

1992-11-01

Four hardware simulation models implementing the FASTBUS protocol are described. The models are written in the VHDL hardware description language to obtain portability, i.e. without relations to any specific simulator. They include two complete FASTBUS devices, a full-duplex segment interconnect and ancillary logic for the segment. In addition, master and slave models using a high level interface to describe FASTBUS operations, are presented. With these models different configurations of FASTBUS systems can be evaluated and the FASTBUS transactions of new devices can be verified. (au)

Storm-time ring current: model-dependent results

Directory of Open Access Journals (Sweden)

N. Yu. Ganushkina

2012-01-01

Full Text Available The main point of the paper is to investigate how much the modeled ring current depends on the representations of magnetic and electric fields and boundary conditions used in simulations. Two storm events, one moderate (SymH minimum of −120 nT on 6–7 November 1997 and one intense (SymH minimum of −230 nT on 21–22 October 1999, are modeled. A rather simple ring current model is employed, namely, the Inner Magnetosphere Particle Transport and Acceleration model (IMPTAM, in order to make the results most evident. Four different magnetic field and two electric field representations and four boundary conditions are used. We find that different combinations of the magnetic and electric field configurations and boundary conditions result in very different modeled ring current, and, therefore, the physical conclusions based on simulation results can differ significantly. A time-dependent boundary outside of 6.6 RE gives a possibility to take into account the particles in the transition region (between dipole and stretched field lines forming partial ring current and near-Earth tail current in that region. Calculating the model SymH* by Biot-Savart's law instead of the widely used Dessler-Parker-Sckopke (DPS relation gives larger and more realistic values, since the currents are calculated in the regions with nondipolar magnetic field. Therefore, the boundary location and the method of SymH* calculation are of key importance for ring current data-model comparisons to be correctly interpreted.

Agent Based Modelling for Social Simulation

NARCIS (Netherlands)

Smit, S.K.; Ubink, E.M.; Vecht, B. van der; Langley, D.J.

2013-01-01

This document is the result of an exploratory project looking into the status of, and opportunities for Agent Based Modelling (ABM) at TNO. The project focussed on ABM applications containing social interactions and human factors, which we termed ABM for social simulation (ABM4SS). During the course

An evaluation of Arctic cloud and radiation processes during the SHEBA year: simulation results from eight Arctic regional climate models

Energy Technology Data Exchange (ETDEWEB)

Wyser, K.; Willen, U. [Rossby Centre, SMHI, Norrkoeping (Sweden); Jones, C.G.; Du, P.; Girard, E.; Laprise, R. [Universite du Quebec a Montreal, Canadian Regional Climate Modelling and Diagnostics Network, Montreal (Canada); Cassano, J.; Serreze, M.; Shaw, M.J. [University of Colorado, Cooperative Institute for Research in Environmental Sciences and Department of Atmospheric and Oceanic Sciences, Boulder, CO (United States); Christensen, J.H. [Danish Meteorological Institute, Copenhagen (Denmark); Curry, J.A. [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA (United States); Dethloff, K.; Rinke, A. [Alfred Wegener Institute for Polar and Marine Research, Research Unit, Potsdam (Germany); Haugen, J.-E.; Koeltzow, M. [Norwegian Meteorological Institute, Oslo (Norway); Jacob, D.; Pfeifer, S. [Max Planck Institute for Meteorology, Hamburg (Germany); Lynch, A. [Monash University, School of Geography and Environmental Science, Melbourne (Australia); Tjernstroem, M.; Zagar, M. [Stockholm University, Department of Meteorology, Stockholm (Sweden)

2008-02-15

Eight atmospheric regional climate models (RCMs) were run for the period September 1997 to October 1998 over the western Arctic Ocean. This period was coincident with the observational campaign of the Surface Heat Budget of the Arctic Ocean (SHEBA) project. The RCMs shared common domains, centred on the SHEBA observation camp, along with a common model horizontal resolution, but differed in their vertical structure and physical parameterizations. All RCMs used the same lateral and surface boundary conditions. Surface downwelling solar and terrestrial radiation, surface albedo, vertically integrated water vapour, liquid water path and cloud cover from each model are evaluated against the SHEBA observation data. Downwelling surface radiation, vertically integrated water vapour and liquid water path are reasonably well simulated at monthly and daily timescales in the model ensemble mean, but with considerable differences among individual models. Simulated surface albedos are relatively accurate in the winter season, but become increasingly inaccurate and variable in the melt season, thereby compromising the net surface radiation budget. Simulated cloud cover is more or less uncorrelated with observed values at the daily timescale. Even for monthly averages, many models do not reproduce the annual cycle correctly. The inter-model spread of simulated cloud-cover is very large, with no model appearing systematically superior. Analysis of the co-variability of terms controlling the surface radiation budget reveal some of the key processes requiring improved treatment in Arctic RCMs. Improvements in the parameterization of cloud amounts and surface albedo are most urgently needed to improve the overall performance of RCMs in the Arctic. (orig.)

Simulation of the Twin Lake tracer tests using different transport models

International Nuclear Information System (INIS)

Kaleris, V.; Klukas, M.; Moltyaner, G.L.

1990-01-01

The 1983 Twin Lake tracer test was simulated using two different sets of the aquifer parameters and three different numerical models. The purpose of the simulations was to identify the parameter set and the model most appropriate to describe the transport phenomena in the Twin Lake aquifer. It is shown that a reliable estimation of the aquifer parameters cannot be obtained from the flow model alone. Transport models must also be used to obtain a reliable estimate of parameters. The method-of-characteristics and random-walk models were used for this purpose. The sensitivity of the results to different execution parameters was evaluated and the required computational efforts were compared. Finally, results obtained by the method of characteristics were compared with the results of a finite element simulation carried out with the same spatial discretization. The comparison demonstrates the influence of the numerical dispersion on the results of the finite element method. Travel time calculations represent a simple way to test the accuracy of the aquifer parameters before transport modeling is done. (Author) (14 refs, 19 figs., 3 tabs.)

Scientific Modeling and simulations

CERN Document Server

Diaz de la Rubia, Tomás

2009-01-01

Showcases the conceptual advantages of modeling which, coupled with the unprecedented computing power through simulations, allow scientists to tackle the formibable problems of our society, such as the search for hydrocarbons, understanding the structure of a virus, or the intersection between simulations and real data in extreme environments

Implementation of angular response function modeling in SPECT simulations with GATE

International Nuclear Information System (INIS)

Descourt, P; Visvikis, D; Carlier, T; Bardies, M; Du, Y; Song, X; Frey, E C; Tsui, B M W; Buvat, I

2010-01-01

Among Monte Carlo simulation codes in medical imaging, the GATE simulation platform is widely used today given its flexibility and accuracy, despite long run times, which in SPECT simulations are mostly spent in tracking photons through the collimators. In this work, a tabulated model of the collimator/detector response was implemented within the GATE framework to significantly reduce the simulation times in SPECT. This implementation uses the angular response function (ARF) model. The performance of the implemented ARF approach has been compared to standard SPECT GATE simulations in terms of the ARF tables' accuracy, overall SPECT system performance and run times. Considering the simulation of the Siemens Symbia T SPECT system using high-energy collimators, differences of less than 1% were measured between the ARF-based and the standard GATE-based simulations, while considering the same noise level in the projections, acceleration factors of up to 180 were obtained when simulating a planar 364 keV source seen with the same SPECT system. The ARF-based and the standard GATE simulation results also agreed very well when considering a four-head SPECT simulation of a realistic Jaszczak phantom filled with iodine-131, with a resulting acceleration factor of 100. In conclusion, the implementation of an ARF-based model of collimator/detector response for SPECT simulations within GATE significantly reduces the simulation run times without compromising accuracy. (note)

Implementation of angular response function modeling in SPECT simulations with GATE

Energy Technology Data Exchange (ETDEWEB)

Descourt, P; Visvikis, D [INSERM, U650, LaTIM, IFR SclnBioS, Universite de Brest, CHU Brest, Brest, F-29200 (France); Carlier, T; Bardies, M [CRCNA INSERM U892, Nantes (France); Du, Y; Song, X; Frey, E C; Tsui, B M W [Department of Radiology, J Hopkins University, Baltimore, MD (United States); Buvat, I, E-mail: dimitris@univ-brest.f [IMNC-UMR 8165 CNRS Universites Paris 7 et Paris 11, Orsay (France)

2010-05-07

Among Monte Carlo simulation codes in medical imaging, the GATE simulation platform is widely used today given its flexibility and accuracy, despite long run times, which in SPECT simulations are mostly spent in tracking photons through the collimators. In this work, a tabulated model of the collimator/detector response was implemented within the GATE framework to significantly reduce the simulation times in SPECT. This implementation uses the angular response function (ARF) model. The performance of the implemented ARF approach has been compared to standard SPECT GATE simulations in terms of the ARF tables' accuracy, overall SPECT system performance and run times. Considering the simulation of the Siemens Symbia T SPECT system using high-energy collimators, differences of less than 1% were measured between the ARF-based and the standard GATE-based simulations, while considering the same noise level in the projections, acceleration factors of up to 180 were obtained when simulating a planar 364 keV source seen with the same SPECT system. The ARF-based and the standard GATE simulation results also agreed very well when considering a four-head SPECT simulation of a realistic Jaszczak phantom filled with iodine-131, with a resulting acceleration factor of 100. In conclusion, the implementation of an ARF-based model of collimator/detector response for SPECT simulations within GATE significantly reduces the simulation run times without compromising accuracy. (note)

Network Modeling and Simulation A Practical Perspective

CERN Document Server

Guizani, Mohsen; Khan, Bilal

2010-01-01

Network Modeling and Simulation is a practical guide to using modeling and simulation to solve real-life problems. The authors give a comprehensive exposition of the core concepts in modeling and simulation, and then systematically address the many practical considerations faced by developers in modeling complex large-scale systems. The authors provide examples from computer and telecommunication networks and use these to illustrate the process of mapping generic simulation concepts to domain-specific problems in different industries and disciplines. Key features: Provides the tools and strate

Latin hypercube sampling and geostatistical modeling of spatial uncertainty in a spatially explicit forest landscape model simulation

Science.gov (United States)

Chonggang Xu; Hong S. He; Yuanman Hu; Yu Chang; Xiuzhen Li; Rencang Bu

2005-01-01

Geostatistical stochastic simulation is always combined with Monte Carlo method to quantify the uncertainty in spatial model simulations. However, due to the relatively long running time of spatially explicit forest models as a result of their complexity, it is always infeasible to generate hundreds or thousands of Monte Carlo simulations. Thus, it is of great...

A Data Stream Model For Runoff Simulation In A Changing Environment

Science.gov (United States)

Yang, Q.; Shao, J.; Zhang, H.; Wang, G.

2017-12-01

Runoff simulation is of great significance for water engineering design, water disaster control, water resources planning and management in a catchment or region. A large number of methods including concept-based process-driven models and statistic-based data-driven models, have been proposed and widely used in worldwide during past decades. Most existing models assume that the relationship among runoff and its impacting factors is stationary. However, in the changing environment (e.g., climate change, human disturbance), their relationship usually evolves over time. In this study, we propose a data stream model for runoff simulation in a changing environment. Specifically, the proposed model works in three steps: learning a rule set, expansion of a rule, and simulation. The first step is to initialize a rule set. When a new observation arrives, the model will check which rule covers it and then use the rule for simulation. Meanwhile, Page-Hinckley (PH) change detection test is used to monitor the online simulation error of each rule. If a change is detected, the corresponding rule is removed from the rule set. In the second step, for each rule, if it covers more than a given number of instance, the rule is expected to expand. In the third step, a simulation model of each leaf node is learnt with a perceptron without activation function, and is updated with adding a newly incoming observation. Taking Fuxi River catchment as a case study, we applied the model to simulate the monthly runoff in the catchment. Results show that abrupt change is detected in the year of 1997 by using the Page-Hinckley change detection test method, which is consistent with the historic record of flooding. In addition, the model achieves good simulation results with the RMSE of 13.326, and outperforms many established methods. The findings demonstrated that the proposed data stream model provides a promising way to simulate runoff in a changing environment.

Hypersonic Combustor Model Inlet CFD Simulations and Experimental Comparisons

Science.gov (United States)

Venkatapathy, E.; TokarcikPolsky, S.; Deiwert, G. S.; Edwards, Thomas A. (Technical Monitor)

1995-01-01

Numerous two-and three-dimensional computational simulations were performed for the inlet associated with the combustor model for the hypersonic propulsion experiment in the NASA Ames 16-Inch Shock Tunnel. The inlet was designed to produce a combustor-inlet flow that is nearly two-dimensional and of sufficient mass flow rate for large scale combustor testing. The three-dimensional simulations demonstrated that the inlet design met all the design objectives and that the inlet produced a very nearly two-dimensional combustor inflow profile. Numerous two-dimensional simulations were performed with various levels of approximations such as in the choice of chemical and physical models, as well as numerical approximations. Parametric studies were conducted to better understand and to characterize the inlet flow. Results from the two-and three-dimensional simulations were used to predict the mass flux entering the combustor and a mass flux correlation as a function of facility stagnation pressure was developed. Surface heat flux and pressure measurements were compared with the computed results and good agreement was found. The computational simulations helped determine the inlet low characteristics in the high enthalpy environment, the important parameters that affect the combustor-inlet flow, and the sensitivity of the inlet flow to various modeling assumptions.

Model reduction for circuit simulation

CERN Document Server

Hinze, Michael; Maten, E Jan W Ter

2011-01-01

Simulation based on mathematical models plays a major role in computer aided design of integrated circuits (ICs). Decreasing structure sizes, increasing packing densities and driving frequencies require the use of refined mathematical models, and to take into account secondary, parasitic effects. This leads to very high dimensional problems which nowadays require simulation times too large for the short time-to-market demands in industry. Modern Model Order Reduction (MOR) techniques present a way out of this dilemma in providing surrogate models which keep the main characteristics of the devi

Modular modeling and simulation of hybrid power trains; Modulare Modellbildung und Simulation von hybriden Antriebstraengen

Energy Technology Data Exchange (ETDEWEB)

Kelz, Gerald; Hirschberg, Wolfgang [Inst. fuer Fahrzeugtechnik, Technische Univ. Graz (Austria)

2009-07-01

The power train of a hybrid vehicle is considerably more complex than that of conventional vehicles. Whilst the topology of a conventional vehicle is normally fixed, the arrangement of the power train components for innovative propulsion systems is a flexible one. The aim is to find those topologies and configurations which are optimal for the intended use. Fuel consumption potentials can be derived with the aid of vehicle longitudinal dynamics simulation. Mostly these simulations are carried out using commercial software which is optimized for the standard topology and do not offer the flexibility to calculate arbitrary topologies. This article covers the modular modeling and the fuel consumption simulation of complex hybrid power trains for topology analysis. A component library for the development of arbitrary hybrid propulsion systems is introduced. The focus lies on an efficient and fast modeling which provides exact simulation results. Several models of power train components are introduced. (orig.)

Simulation and Modeling Methodologies, Technologies and Applications

CERN Document Server

Filipe, Joaquim; Kacprzyk, Janusz; Pina, Nuno

2014-01-01

This book includes extended and revised versions of a set of selected papers from the 2012 International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH 2012) which was sponsored by the Institute for Systems and Technologies of Information, Control and Communication (INSTICC) and held in Rome, Italy. SIMULTECH 2012 was technically co-sponsored by the Society for Modeling & Simulation International (SCS), GDR I3, Lionphant Simulation, Simulation Team and IFIP and held in cooperation with AIS Special Interest Group of Modeling and Simulation (AIS SIGMAS) and the Movimento Italiano Modellazione e Simulazione (MIMOS).

Understanding Emergency Care Delivery Through Computer Simulation Modeling.

Science.gov (United States)

Laker, Lauren F; Torabi, Elham; France, Daniel J; Froehle, Craig M; Goldlust, Eric J; Hoot, Nathan R; Kasaie, Parastu; Lyons, Michael S; Barg-Walkow, Laura H; Ward, Michael J; Wears, Robert L

2018-02-01

In 2017, Academic Emergency Medicine convened a consensus conference entitled, "Catalyzing System Change through Health Care Simulation: Systems, Competency, and Outcomes." This article, a product of the breakout session on "understanding complex interactions through systems modeling," explores the role that computer simulation modeling can and should play in research and development of emergency care delivery systems. This article discusses areas central to the use of computer simulation modeling in emergency care research. The four central approaches to computer simulation modeling are described (Monte Carlo simulation, system dynamics modeling, discrete-event simulation, and agent-based simulation), along with problems amenable to their use and relevant examples to emergency care. Also discussed is an introduction to available software modeling platforms and how to explore their use for research, along with a research agenda for computer simulation modeling. Through this article, our goal is to enhance adoption of computer simulation, a set of methods that hold great promise in addressing emergency care organization and design challenges. © 2017 by the Society for Academic Emergency Medicine.

Design, modeling, simulation and evaluation of a distributed energy system

Science.gov (United States)

Cultura, Ambrosio B., II

This dissertation presents the design, modeling, simulation and evaluation of distributed energy resources (DER) consisting of photovoltaics (PV), wind turbines, batteries, a PEM fuel cell and supercapacitors. The distributed energy resources installed at UMass Lowell consist of the following: 2.5kW PV, 44kWhr lead acid batteries and 1500W, 500W & 300W wind turbines, which were installed before year 2000. Recently added to that are the following: 10.56 kW PV array, 2.4 kW wind turbine, 29 kWhr Lead acid batteries, a 1.2 kW PEM fuel cell and 4-140F supercapacitors. Each newly added energy resource has been designed, modeled, simulated and evaluated before its integration into the existing PV/Wind grid-connected system. The Mathematical and Simulink model of each system was derived and validated by comparing the simulated and experimental results. The Simulated results of energy generated from a 10.56kW PV system are in good agreement with the experimental results. A detailed electrical model of a 2.4kW wind turbine system equipped with a permanent magnet generator, diode rectifier, boost converter and inverter is presented. The analysis of the results demonstrates the effectiveness of the constructed simulink model, and can be used to predict the performance of the wind turbine. It was observed that a PEM fuel cell has a very fast response to load changes. Moreover, the model has validated the actual operation of the PEM fuel cell, showing that the simulated results in Matlab Simulink are consistent with the experimental results. The equivalent mathematical equation, derived from an electrical model of the supercapacitor, is used to simulate its voltage response. The model is completely capable of simulating its voltage behavior, and can predict the charge time and discharge time of voltages on the supercapacitor. The bi-directional dc-dc converter was designed in order to connect the 48V battery bank storage to the 24V battery bank storage. This connection was

Simulating streamflow and water table depth with a coupled hydrological model

Directory of Open Access Journals (Sweden)

Alphonce Chenjerayi Guzha

2010-09-01

Full Text Available A coupled model integrating MODFLOW and TOPNET with the models interacting through the exchange of recharge and baseflow and river-aquifer interactions was developed and applied to the Big Darby Watershed in Ohio, USA. Calibration and validation results show that there is generally good agreement between measured streamflow and simulated results from the coupled model. At two gauging stations, average goodness of fit (R2, percent bias (PB, and Nash Sutcliffe efficiency (ENS values of 0.83, 11.15%, and 0.83, respectively, were obtained for simulation of streamflow during calibration, and values of 0.84, 8.75%, and 0.85, respectively, were obtained for validation. The simulated water table depths yielded average R2 values of 0.77 and 0.76 for calibration and validation, respectively. The good match between measured and simulated streamflows and water table depths demonstrates that the model is capable of adequately simulating streamflows and water table depths in the watershed and also capturing the influence of spatial and temporal variation in recharge.

Object Oriented Modelling and Dynamical Simulation

DEFF Research Database (Denmark)

Wagner, Falko Jens; Poulsen, Mikael Zebbelin

1998-01-01

This report with appendix describes the work done in master project at DTU.The goal of the project was to develop a concept for simulation of dynamical systems based on object oriented methods.The result was a library of C++-classes, for use when both building componentbased models and when...

The NASA Ames Hypersonic Combustor-Model Inlet CFD Simulations and Experimental Comparisons

Science.gov (United States)

Venkatapathy, E.; Tokarcik-Polsky, S.; Deiwert, G. S.; Edwards, Thomas A. (Technical Monitor)

1995-01-01

Computations have been performed on a three-dimensional inlet associated with the NASA Ames combustor model for the hypersonic propulsion experiment in the 16-inch shock tunnel. The 3-dimensional inlet was designed to have the combustor inlet flow nearly two-dimensional and of sufficient mass flow necessary for combustion. The 16-inch shock tunnel experiment is a short duration test with test time of the order of milliseconds. The flow through the inlet is in chemical non-equilibrium. Two test entries have been completed and limited experimental results for the inlet region of the combustor-model are available. A number of CFD simulations, with various levels of simplifications such as 2-D simulations, 3-D simulations with and without chemical reactions, simulations with and without turbulent conditions, etc., have been performed. These simulations have helped determine the model inlet flow characteristics and the important factors that affect the combustor inlet flow and the sensitivity of the flow field to these simplifications. In the proposed paper, CFD modeling of the hypersonic inlet, results from the simulations and comparison with available experimental results will be presented.

Virtual milk for modelling and simulation of dairy processes.

Science.gov (United States)

Munir, M T; Zhang, Y; Yu, W; Wilson, D I; Young, B R

2016-05-01

The modeling of dairy processing using a generic process simulator suffers from shortcomings, given that many simulators do not contain milk components in their component libraries. Recently, pseudo-milk components for a commercial process simulator were proposed for simulation and the current work extends this pseudo-milk concept by studying the effect of both total milk solids and temperature on key physical properties such as thermal conductivity, density, viscosity, and heat capacity. This paper also uses expanded fluid and power law models to predict milk viscosity over the temperature range from 4 to 75°C and develops a succinct regressed model for heat capacity as a function of temperature and fat composition. The pseudo-milk was validated by comparing the simulated and actual values of the physical properties of milk. The milk thermal conductivity, density, viscosity, and heat capacity showed differences of less than 2, 4, 3, and 1.5%, respectively, between the simulated results and actual values. This work extends the capabilities of the previously proposed pseudo-milk and of a process simulator to model dairy processes, processing different types of milk (e.g., whole milk, skim milk, and concentrated milk) with different intrinsic compositions, and to predict correct material and energy balances for dairy processes. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Hybrid Reynolds-Averaged/Large Eddy Simulation of a Cavity Flameholder; Assessment of Modeling Sensitivities

Science.gov (United States)

Baurle, R. A.

2015-01-01

Steady-state and scale-resolving simulations have been performed for flow in and around a model scramjet combustor flameholder. The cases simulated corresponded to those used to examine this flowfield experimentally using particle image velocimetry. A variety of turbulence models were used for the steady-state Reynolds-averaged simulations which included both linear and non-linear eddy viscosity models. The scale-resolving simulations used a hybrid Reynolds-averaged / large eddy simulation strategy that is designed to be a large eddy simulation everywhere except in the inner portion (log layer and below) of the boundary layer. Hence, this formulation can be regarded as a wall-modeled large eddy simulation. This effort was undertaken to formally assess the performance of the hybrid Reynolds-averaged / large eddy simulation modeling approach in a flowfield of interest to the scramjet research community. The numerical errors were quantified for both the steady-state and scale-resolving simulations prior to making any claims of predictive accuracy relative to the measurements. The steady-state Reynolds-averaged results showed a high degree of variability when comparing the predictions obtained from each turbulence model, with the non-linear eddy viscosity model (an explicit algebraic stress model) providing the most accurate prediction of the measured values. The hybrid Reynolds-averaged/large eddy simulation results were carefully scrutinized to ensure that even the coarsest grid had an acceptable level of resolution for large eddy simulation, and that the time-averaged statistics were acceptably accurate. The autocorrelation and its Fourier transform were the primary tools used for this assessment. The statistics extracted from the hybrid simulation strategy proved to be more accurate than the Reynolds-averaged results obtained using the linear eddy viscosity models. However, there was no predictive improvement noted over the results obtained from the explicit

eShopper modeling and simulation

Science.gov (United States)

Petrushin, Valery A.

2001-03-01

The advent of e-commerce gives an opportunity to shift the paradigm of customer communication into a highly interactive mode. The new generation of commercial Web servers, such as the Blue Martini's server, combines the collection of data on a customer behavior with real-time processing and dynamic tailoring of a feedback page. The new opportunities for direct product marketing and cross selling are arriving. The key problem is what kind of information do we need to achieve these goals, or in other words, how do we model the customer? The paper is devoted to customer modeling and simulation. The focus is on modeling an individual customer. The model is based on the customer's transaction data, click stream data, and demographics. The model includes the hierarchical profile of a customer's preferences to different types of products and brands; consumption models for the different types of products; the current focus, trends, and stochastic models for time intervals between purchases; product affinity models; and some generalized features, such as purchasing power, sensitivity to advertising, price sensitivity, etc. This type of model is used for predicting the date of the next visit, overall spending, and spending for different types of products and brands. For some type of stores (for example, a supermarket) and stable customers, it is possible to forecast the shopping lists rather accurately. The forecasting techniques are discussed. The forecasting results can be used for on- line direct marketing, customer retention, and inventory management. The customer model can also be used as a generative model for simulating the customer's purchasing behavior in different situations and for estimating customer's features.

Non-Stationary Modelling and Simulation of Near-Source Earthquake Ground Motion

DEFF Research Database (Denmark)

Skjærbæk, P. S.; Kirkegaard, Poul Henning; Fouskitakis, G. N.

1997-01-01

This paper is concerned with modelling and simulation of near-source earthquake ground motion. Recent studies have revealed that these motions show heavy non-stationary behaviour with very low frequencies dominating parts of the earthquake sequence. Modeling and simulation of this behaviour...... by an epicentral distance of 16 km and measured during the 1979 Imperial Valley earthquake in California (U .S .A.). The results of the study indicate that while all three approaches can successfully predict near-source ground motions, the Neural Network based one gives somewhat poorer simulation results....

Non-Stationary Modelling and Simulation of Near-Source Earthquake Ground Motion

DEFF Research Database (Denmark)

Skjærbæk, P. S.; Kirkegaard, Poul Henning; Fouskitakis, G. N.

This paper is concerned with modelling and simulation of near-source earthquake ground motion. Recent studies have revealed that these motions show heavy non-stationary behaviour with very low frequencies dominating parts of the earthquake sequence. Modelling and simulation of this behaviour...... by an epicentral distance of 16 km and measured during the 1979 Imperial valley earthquake in California (USA). The results of the study indicate that while all three approaches can succesfully predict near-source ground motions, the Neural Network based one gives somewhat poorer simulation results....

Numerical simulations of atmospheric dispersion of iodine-131 by different models.

Directory of Open Access Journals (Sweden)

Ádám Leelőssy

Full Text Available Nowadays, several dispersion models are available to simulate the transport processes of air pollutants and toxic substances including radionuclides in the atmosphere. Reliability of atmospheric transport models has been demonstrated in several recent cases from local to global scale; however, very few actual emission data are available to evaluate model results in real-life cases. In this study, the atmospheric dispersion of 131I emitted to the atmosphere during an industrial process was simulated with different models, namely the WRF-Chem Eulerian online coupled model and the HYSPLIT and the RAPTOR Lagrangian models. Although only limited data of 131I detections has been available, the accuracy of modeled plume direction could be evaluated in complex late autumn weather situations. For the studied cases, the general reliability of models has been demonstrated. However, serious uncertainties arise related to low level inversions, above all in case of an emission event on 4 November 2011, when an important wind shear caused a significant difference between simulated and real transport directions. Results underline the importance of prudent interpretation of dispersion model results and the identification of weather conditions with a potential to cause large model errors.

SIMULATING AN EVOLUTIONARY MULTI-AGENT BASED MODEL OF THE STOCK MARKET

Directory of Open Access Journals (Sweden)

Diana MARICA

2015-08-01

Full Text Available The paper focuses on artificial stock market simulations using a multi-agent model incorporating 2,000 heterogeneous agents interacting on the artificial market. The agents interaction is due to trading activity on the market through a call auction trading mechanism. The multi-agent model uses evolutionary techniques such as genetic programming in order to generate an adaptive and evolving population of agents. Each artificial agent is endowed with wealth and a genetic programming induced trading strategy. The trading strategy evolves and adapts to the new market conditions through a process called breeding, which implies that at each simulation step, new agents with better trading strategies are generated by the model, from recombining the best performing trading strategies and replacing the agents which have the worst performing trading strategies. The simulation model was build with the help of the simulation software Altreva Adaptive Modeler which offers a suitable platform for financial market simulations of evolutionary agent based models, the S&P500 composite index being used as a benchmark for the simulation results.

Responses of the ocean carbon cycle to climate change: Results from an earth system climate model simulation

Institute of Scientific and Technical Information of China (English)

WANG Shuang-Jing; CAO Long; LI Na

2014-01-01

Based on simulations using the University of Victoria’s Earth System Climate Model, we analyzed the responses of the ocean carbon cycle to increasing atmospheric CO2 levels and climate change from 1800 to 2500 following the RCP 8.5 scenario and its extension. Compared to simulations without climate change, the simulation with a climate sensitivity of 3.0 K shows that in 2100, due to increased atmospheric CO2 concentrations, the simulated sea surface temperature increases by 2.7 K, the intensity of the North Atlantic deep water formation reduces by4.5 Sv, and the oceanic uptake of anthropogenic CO2 decreases by 0.8 Pg C. Climate change is also found to have a large effect on the North Atlantic’s ocean column inventory of anthropogenic CO2. Between the years 1800 and 2500, compared with the simulation with no climate change, the simulation with climate change causes a reduction in the total anthropogenic CO2 column inventory over the entire ocean and in North Atlantic by 23.1% and 32.0%, respectively. A set of simulations with climate sensitivity variations from 0.5 K to 4.5 K show that with greater climate sensitivity climate change would have a greater effect in reducing the ocean’s ability to absorb CO2 from the atmosphere.

Simulation Models of Human Decision-Making Processes

Directory of Open Access Journals (Sweden)

Nina RIZUN

2014-10-01

Full Text Available The main purpose of the paper is presentation of the new concept of human decision-making process modeling via using the analogy with Automatic Control Theory. From the author's point of view this concept allows to develop and improve the theory of decision-making in terms of the study and classification of specificity of the human intellectual processes in different conditions. It was proved that the main distinguishing feature between the Heuristic / Intuitive and Rational Decision-Making Models is the presence of so-called phenomenon of "enrichment" of the input information with human propensity, hobbies, tendencies, expectations, axioms and judgments, presumptions or bias and their justification. In order to obtain additional knowledge about the basic intellectual processes as well as the possibility of modeling the decision results in various parameters characterizing the decision-maker, the complex of the simulation models was developed. These models are based on the assumptions that:  basic intellectual processes of the Rational Decision-Making Model can be adequately simulated and identified by the transient processes of the proportional-integral-derivative controller; basic intellectual processes of the Bounded Rationality and Intuitive Models can be adequately simulated and identified by the transient processes of the nonlinear elements.The taxonomy of the most typical automatic control theory elements and their compliance with certain decision-making models with a point of view of decision-making process specificity and decision-maker behavior during a certain time of professional activity was obtained.

From single Debye-Hückel chains to polyelectrolyte solutions: Simulation results

Science.gov (United States)

Kremer, Kurt

1996-03-01

This lecture will present results from simulations of single weakly charged flexible chains, where the electrostatic part of the interaction is modeled by a Debye-Hückel potential,( with U. Micka, IFF, Forschungszentrum Jülich, 52425 Jülich, Germany) as well as simulations of polyelectrolyte solutions, where the counterions are explicitly taken into account( with M. J. Stevens, Sandia Nat. Lab., Albuquerque, NM 87185-1111) ( M. J. Stevens, K. Kremer, JCP 103), 1669 (1995). The first set of the simulations is meant to clear a recent contoversy on the dependency of the persistence length LP on the screening length Γ. While the analytic theories give Lp ~ Γ^x with either x=1 or x=2, the simulations find for all experimentally accessible chain lengths a varying exponent, which is significantly smaller than 1. This causes serious doubts on the applicability of this model for weakly charged polyelectrolytes in general. The second part deals with strongly charged flexible polyelectrolytes in salt free solution. These simulations are performed for multichain systems. The full Coulomb interactions of the monomers and counterions are treated explicitly. Experimental measurements of the osmotic pressure and the structure factor are reproduced and extended. The simulations reveal a new picture of the chain structure based on calculations of the structure factor, persistence length, end-to-end distance, etc. Even at very low density, the chains show significant bending. Furthermore, the chains contract significantly before they start to overlap. We also show that counterion condensation dramatically alters the chain structure, even for a good solvent backbone.

The validation of evacuation simulation models through the analysis of behavioural uncertainty

International Nuclear Information System (INIS)

Lovreglio, Ruggiero; Ronchi, Enrico; Borri, Dino

2014-01-01

Both experimental and simulation data on fire evacuation are influenced by a component of uncertainty caused by the impact of the unexplained variance in human behaviour, namely behavioural uncertainty (BU). Evacuation model validation studies should include the study of this type of uncertainty during the comparison of experiments and simulation results. An evacuation model validation procedure is introduced in this paper to study the impact of BU. This methodology is presented through a case study for the comparison between repeated experimental data and simulation results produced by FDS+Evac, an evacuation model for the simulation of human behaviour in fire, which makes use of distribution laws. - Highlights: • Validation of evacuation models is investigated. • Quantitative evaluation of behavioural uncertainty is performed. • A validation procedure is presented through an evacuation case study

Optimization Model for Web Based Multimodal Interactive Simulations.

Science.gov (United States)

Halic, Tansel; Ahn, Woojin; De, Suvranu

2015-07-15

This paper presents a technique for optimizing the performance of web based multimodal interactive simulations. For such applications where visual quality and the performance of simulations directly influence user experience, overloading of hardware resources may result in unsatisfactory reduction in the quality of the simulation and user satisfaction. However, optimization of simulation performance on individual hardware platforms is not practical. Hence, we present a mixed integer programming model to optimize the performance of graphical rendering and simulation performance while satisfying application specific constraints. Our approach includes three distinct phases: identification, optimization and update . In the identification phase, the computing and rendering capabilities of the client device are evaluated using an exploratory proxy code. This data is utilized in conjunction with user specified design requirements in the optimization phase to ensure best possible computational resource allocation. The optimum solution is used for rendering (e.g. texture size, canvas resolution) and simulation parameters (e.g. simulation domain) in the update phase. Test results are presented on multiple hardware platforms with diverse computing and graphics capabilities to demonstrate the effectiveness of our approach.

A constitutive model and numerical simulation of sintering processes at macroscopic level

Science.gov (United States)

Wawrzyk, Krzysztof; Kowalczyk, Piotr; Nosewicz, Szymon; Rojek, Jerzy

2018-01-01

This paper presents modelling of both single and double-phase powder sintering processes at the macroscopic level. In particular, its constitutive formulation, numerical implementation and numerical tests are described. The macroscopic constitutive model is based on the assumption that the sintered material is a continuous medium. The parameters of the constitutive model for material under sintering are determined by simulation of sintering at the microscopic level using a micro-scale model. Numerical tests were carried out for a cylindrical specimen under hydrostatic and uniaxial pressure. Results of macroscopic analysis are compared against the microscopic model results. Moreover, numerical simulations are validated by comparison with experimental results. The simulations and preparation of the model are carried out by Abaqus FEA - a software for finite element analysis and computer-aided engineering. A mechanical model is defined by the user procedure "Vumat" which is developed by the first author in Fortran programming language. Modelling presented in the paper can be used to optimize and to better understand the process.

Automated Simulation Model Generation

NARCIS (Netherlands)

Huang, Y.

2013-01-01

One of today's challenges in the field of modeling and simulation is to model increasingly larger and more complex systems. Complex models take long to develop and incur high costs. With the advances in data collection technologies and more popular use of computer-aided systems, more data has become

An introduction to enterprise modeling and simulation

Energy Technology Data Exchange (ETDEWEB)

Ostic, J.K.; Cannon, C.E. [Los Alamos National Lab., NM (United States). Technology Modeling and Analysis Group

1996-09-01

As part of an ongoing effort to continuously improve productivity, quality, and efficiency of both industry and Department of Energy enterprises, Los Alamos National Laboratory is investigating various manufacturing and business enterprise simulation methods. A number of enterprise simulation software models are being developed to enable engineering analysis of enterprise activities. In this document the authors define the scope of enterprise modeling and simulation efforts, and review recent work in enterprise simulation at Los Alamos National Laboratory as well as at other industrial, academic, and research institutions. References of enterprise modeling and simulation methods and a glossary of enterprise-related terms are provided.

Semi-Automated Processing of Trajectory Simulator Output Files for Model Evaluation

Science.gov (United States)

2018-01-01

ARL-TR-8284 ● JAN 2018 US Army Research Laboratory Semi-Automated Processing of Trajectory Simulator Output Files for Model...Semi-Automated Processing of Trajectory Simulator Output Files for Model Evaluation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...although some minor changes may be needed. The program processes a GTRAJ output text file that contains results from 2 or more simulations , where each

Columnar modelling of nucleation burst evolution in the convective boundary layer – first results from a feasibility study Part IV: A compilation of previous observations for valuation of simulation results from a columnar modelling study

Directory of Open Access Journals (Sweden)

O. Hellmuth

2006-01-01

Full Text Available In the preceding Papers I, II and III a revised columnar high-order modelling approach to model gas-aerosol-turbulence interactions in the convective boundary layer (CBL was proposed, and simulation results of two synthetic nucleation scenarios (binary vs. ternary on new particle formation (NPF in the anthropogenically influenced CBL were presented and discussed. The purpose of the present finishing Paper IV is twofold: Firstly, an attempt is made to compile previous observational findings on NPF bursts in the CBL, obtained from a number of field experiments. Secondly, the scenario simulations discussed in Paper III will be evaluated with respect to the role of CBL turbulence in NPF burst evolution. It was demonstrated, that completely different nucleation mechanisms can lead to the occurrence of NPF bursts in the surface layer, but the corresponding evolution patterns strongly differ with respect to the origin, amplitude and phase of the NPF burst as well as with respect to the time-height evolution of turbulent vertical fluxes and double correlation terms of physicochemical and aerosoldynamical variables. The large differences between the binary and ternary case scenario indicate, that ammonia (NH3 can not be considered as a time-independent tuning parameter in nucleation modelling. Its contribution to the evolution of the NPF burst pattern is much more complicated and reflects the influence of CBL turbulence as well as the strong non-linearity of the ternary nucleation rate. The impact of water (H2O vapour on the nucleation rate is quite varying depending on the considered nucleation mechanism. According to the classical theory of binary nucleation involving H2O and sulphuric acid (H2SO4, H2O vapour favours NPF, according to the classical theory of ternary nuncleation involving H2O, H2SO4 and NH3 and according to organic nucleation via chemical reactions involving stabilised Criegee intermediates (SCIs, H2O vapour disfavours nucleation, and

Modeling and Simulation of Variable Mass, Flexible Structures

Science.gov (United States)

Tobbe, Patrick A.; Matras, Alex L.; Wilson, Heath E.

2009-01-01

distribution of mass in the fuel tank or Solid Rocket Booster (SRB) case for various propellant levels. Based on the mass consumed by the liquid engine or SRB, the appropriate propellant model is coupled with the dry structure model for the stage. Then using vehicle configuration data, the integrated vehicle model is assembled and operated on by the constant system shape functions. The system mode shapes and frequencies can then be computed from the resulting generalized mass and stiffness matrices for that mass configuration. The rigid body mass properties of the vehicle are derived from the integrated vehicle model. The coupling terms between the vehicle rigid body motion and elastic deformation are also updated from the constant system shape functions and the integrated vehicle model. This approach was first used to analyze variable mass spinning beams and then prototyped into a generic dynamics simulation engine. The resulting code was tested against Crew Launch Vehicle (CLV-)class problems worked in the TREETOPS simulation package and by Wilson [2]. The Ares I System Integration Laboratory (SIL) is currently being developed at the Marshall Space Flight Center (MSFC) to test vehicle avionics hardware and software in a hardware-in-the-loop (HWIL) environment and certify that the integrated system is prepared for flight. The Ares I SIL utilizes the Ares Real-Time Environment for Modeling, Integration, and Simulation (ARTEMIS) tool to simulate the launch vehicle and stimulate avionics hardware. Due to the presence of vehicle control system filters and the thrust oscillation suppression system, which are tuned to the structural characteristics of the vehicle, ARTEMIS must incorporate accurate structural models of the Ares I launch vehicle. The ARTEMIS core dynamics simulation models the highly coupled nature of the vehicle flexible body dynamics, propellant slosh, and vehicle nozzle inertia effects combined with mass and flexible body properties that vary significant with time

Simulations of ITER disruption and VDE scenarios with TSC and comparison with DINA results

International Nuclear Information System (INIS)

Bandyopadhyay, I.

2008-01-01

Vertical Displacement Events (VDEs) and plasma current disruptions pose one of the major concerns for the lifetime of in-vessel components in ITER, as well as for machine robustness, as large electromagnetic and thermal loads will induced at such events. Hence, accurate modelling of such events is crucial for estimating disruption induced forces. In the past, ITER disruption modelling has been carried out for ITER using the DINA code. However, since predictive simulations of such events depend on a large number of model assumptions, there exists chances of large error bars on the model predictions. As such it is imperative to validate the code results with other models. Towards this objective, we have carried out the VDE and Disruption simulations using the TSC code and the results are compared with the earlier DINA predictions. A detailed electromagnetic model of the ITER vessel, blankets and the first wall components has been created in TSC. In both VDE and disruption cases, the initial plasma is taken as ITER reference scenario 2 end of burn (EOB) specifications with I p = 15 MA, B t = 5 .3 T, e > 8.8 keV, e > = 1.1 x 10 20 m -3 . The plasma current disruption is initiated by dropping the plasma β in 1 msec, so that after the β crash e > = 6 eV, following which the plasma position control is switched off, resulting in a plasma current quench in about 65 msec. On the other hand, in the VDE case, the plasma control is switched off which results in either upward or downward VDE depending on the initial position of the plasma current centroid. In this case the plasma current remains close to 15 MA for a much longer time, about 700 msec in the simulations till the edge safety factor (q) becomes less than 1.5, following which the β is crashed resulting in plasma current quench. Significant differences exist in the DINA and TSC models, for example, even though the plasma current quench rate predicted by the models matches well in till the halo currents start flowing

Models and simulations

International Nuclear Information System (INIS)

Lee, M.J.; Sheppard, J.C.; Sullenberger, M.; Woodley, M.D.

1983-09-01

On-line mathematical models have been used successfully for computer controlled operation of SPEAR and PEP. The same model control concept is being implemented for the operation of the LINAC and for the Damping Ring, which will be part of the Stanford Linear Collider (SLC). The purpose of this paper is to describe the general relationships between models, simulations and the control system for any machine at SLAC. The work we have done on the development of the empirical model for the Damping Ring will be presented as an example

Event-based Simulation Model for Quantum Optics Experiments

NARCIS (Netherlands)

De Raedt, H.; Michielsen, K.; Jaeger, G; Khrennikov, A; Schlosshauer, M; Weihs, G

2011-01-01

We present a corpuscular simulation model of optical phenomena that does not require the knowledge of the solution of a wave equation of the whole system and reproduces the results of Maxwell's theory by generating detection events one-by-one. The event-based corpuscular model gives a unified

Modeling and simulation of pressurized water reactor power plant

International Nuclear Information System (INIS)

Wang, S.J.

1983-01-01

Two kinds of balance of plant (BOP) models of a pressurized water reactor (PWR) system are developed in this work - the detailed BOP model and the simple BOP model. The detailed model is used to simulate the normal operational performance of a whole BOP system. The simple model is used to combine with the NSSS model for a whole plant simulation. The trends of the steady state values of the detailed model are correct and the dynamic responses are reasonable. The simple BOP model approach starts the modelling work from the overall point of view. The response of the normalized turbine power and the feedwater inlet temperature to the steam generator of the simple model are compared with those of the detailed model. Both the steady state values and the dynamic responses are close to those of the detailed model. The simple BOP model is found adequate to represent the main performance of the BOP system. The simple balance of plant model was coupled with a NSSS model for a whole plant simulation. The NSSS model consists of the reactor core model, the steam generator model, and the coolant temperature control system. A closed loop whole plant simulation for an electric load perturbation was performed. The results are plausible. The coupling effect between the NSSS system and the BOP system was analyzed. The feedback of the BOP system has little effect on the steam generator performance, while the performance of the BOP system is strongly affected by the steam flow rate from the NSSS

Assessing the convergence of LHS Monte Carlo simulations of wastewater treatment models.

Science.gov (United States)

Benedetti, Lorenzo; Claeys, Filip; Nopens, Ingmar; Vanrolleghem, Peter A

2011-01-01

Monte Carlo (MC) simulation appears to be the only currently adopted tool to estimate global sensitivities and uncertainties in wastewater treatment modelling. Such models are highly complex, dynamic and non-linear, requiring long computation times, especially in the scope of MC simulation, due to the large number of simulations usually required. However, no stopping rule to decide on the number of simulations required to achieve a given confidence in the MC simulation results has been adopted so far in the field. In this work, a pragmatic method is proposed to minimize the computation time by using a combination of several criteria. It makes no use of prior knowledge about the model, is very simple, intuitive and can be automated: all convenient features in engineering applications. A case study is used to show an application of the method, and the results indicate that the required number of simulations strongly depends on the model output(s) selected, and on the type and desired accuracy of the analysis conducted. Hence, no prior indication is available regarding the necessary number of MC simulations, but the proposed method is capable of dealing with these variations and stopping the calculations after convergence is reached.

Simulating the SU(2) sector of the standard model with dynamical fermions

International Nuclear Information System (INIS)

Lee, I. Hsiu.

1988-01-01

The two-generation SU(2) sector of the standard model with zero Yukawa couplings is studied on the lattice. The results from analytic studies and simulations with quenched fermions are reviewed. The methods and results of a Langevin simulation with dynamical fermions are presented. Implications for the strongly coupled standard model are mentioned. 23 refs

Simulation model of a PWR power plant

International Nuclear Information System (INIS)

Larsen, N.

1987-03-01

A simulation model of a hypothetical PWR power plant is described. A large number of disturbances and failures in plant function can be simulated. The model is written as seven modules to the modular simulation system for continuous processes DYSIM and serves also as a user example of this system. The model runs in Fortran 77 on the IBM-PC-AT. (author)

Fuzzy Simulation-Optimization Model for Waste Load Allocation

Directory of Open Access Journals (Sweden)

Motahhare Saadatpour

2006-01-01

Full Text Available This paper present simulation-optimization models for waste load allocation from multiple point sources which include uncertainty due to vagueness of the parameters and goals. This model employs fuzzy sets with appropriate membership functions to deal with uncertainties due to vagueness. The fuzzy waste load allocation model (FWLAM incorporate QUAL2E as a water quality simulation model and Genetic Algorithm (GA as an optimization tool to find the optimal combination of the fraction removal level to the dischargers and pollution control agency (PCA. Penalty functions are employed to control the violations in the system.  The results demonstrate that the goal of PCA to achieve the best water quality and the goal of the dischargers to use the full assimilative capacity of the river have not been satisfied completely and a compromise solution between these goals is provided. This fuzzy optimization model with genetic algorithm has been used for a hypothetical problem. Results demonstrate a very suitable convergence of proposed optimization algorithm to the global optima.

How do rigid-lid assumption affect LES simulation results at high Reynolds flows?

Science.gov (United States)

Khosronejad, Ali; Farhadzadeh, Ali; SBU Collaboration

2017-11-01

This research is motivated by the work of Kara et al., JHE, 2015. They employed LES to model flow around a model of abutment at a Re number of 27,000. They showed that first-order turbulence characteristics obtained by rigid-lid (RL) assumption compares fairly well with those of level-set (LS) method. Concerning the second-order statistics, however, their simulation results showed a significant dependence on the method used to describe the free surface. This finding can have important implications for open channel flow modeling. The Reynolds number for typical open channel flows, however, could be much larger than that of Kara et al.'s test case. Herein, we replicate the reported study by augmenting the geometric and hydraulic scales to reach a Re number of one order of magnitude larger ( 200,000). The Virtual Flow Simulator (VFS-Geophysics) model in its LES mode is used to simulate the test case using both RL and LS methods. The computational results are validated using measured flow and free-surface data from our laboratory experiments. Our goal is to investigate the effects of RL assumption on both first-order and second order statistics at high Reynolds numbers that occur in natural waterways. Acknowledgment: Computational resources are provided by the Center of Excellence in Wireless & Information Technology (CEWIT) of Stony Brook University.

Hydrology-oriented forest management trade-offs. A modeling framework coupling field data, simulation results and Bayesian Networks.

Science.gov (United States)

Garcia-Prats, Alberto; González-Sanchis, María; Del Campo, Antonio D; Lull, Cristina

2018-05-23

Hydrology-oriented forest management sets water as key factor of the forest management for adaptation due to water is the most limiting factor in the Mediterranean forest ecosystems. The aim of this study was to apply Bayesian Network modeling to assess potential indirect effects and trade-offs when hydrology-oriented forest management is applied to a real Mediterranean forest ecosystem. Water, carbon and nitrogen cycles, and forest fire risk were included in the modeling framework. Field data from experimental plots were employed to calibrate and validate the mechanistic Biome-BGCMuSo model that simulates the storage and flux of water, carbon, and nitrogen between the ecosystem and the atmosphere. Many other 50-year long scenarios with different conditions to the ones measured in the field experiment were simulated and the outcomes employed to build the Bayesian Network in a linked chain of models. Hydrology-oriented forest management was very positive insofar as more water was made available to the stand because of an interception reduction. This resource was made available to the stand, which increased the evapotranspiration and its components, the soil water content and a slightly increase of deep percolation. Conversely, Stemflow was drastically reduced. No effect was observed on Runof due to the thinning treatment. The soil organic carbon content was also increased which in turn caused a greater respiration. The long-term effect of the thinning treatment on the LAI was very positive. This was undoubtedly due to the increased vigor generated by the greater availability of water and nutrients for the stand and the reduction of competence between trees. This greater activity resulted in an increase in GPP and vegetation carbon, and therefore, we would expect a higher carbon sequestration. It is worth emphasizing that this extra amount of water and nutrients was taken up by the stand and did not entail any loss of nutrients. Copyright © 2018 Elsevier B.V. All

RF feedback simulation results for PEP-II

International Nuclear Information System (INIS)

Tighe, R.; Corredoura, P.

1995-06-01

A model of the RF feedback system for PEP-II has been developed to provide time-domain simulation and frequency-domain analysis of the complete system. The model includes the longitudinal beam dynamics, cavity fundamental resonance, feedback loops, and the nonlinear klystron operating near saturation. Transients from an ion clearing gap and a reference phase modulation from the longitudinal feedback system are also studied. Growth rates are predicted and overall system stability examined

Clock error models for simulation and estimation

International Nuclear Information System (INIS)

Meditch, J.S.

1981-10-01

Mathematical models for the simulation and estimation of errors in precision oscillators used as time references in satellite navigation systems are developed. The results, based on all currently known oscillator error sources, are directly implementable on a digital computer. The simulation formulation is sufficiently flexible to allow for the inclusion or exclusion of individual error sources as desired. The estimation algorithms, following from Kalman filter theory, provide directly for the error analysis of clock errors in both filtering and prediction

Comparing Productivity Simulated with Inventory Data Using Different Modelling Technologies

Science.gov (United States)

Klopf, M.; Pietsch, S. A.; Hasenauer, H.

2009-04-01

The Lime Stone National Park in Austria was established in 1997 to protect sensible lime stone soils from degradation due to heavy forest management. Since 1997 the management activities were successively reduced and standing volume and coarse woody debris (CWD) increased and degraded soils began to recover. One option to study the rehabilitation process towards natural virgin forest state is the use of modelling technology. In this study we will test two different modelling approaches for their applicability to Lime Stone National Park. We will compare standing tree volume simulated resulting from (i) the individual tree growth model MOSES, and (ii) the species and management sensitive adaptation of the biogeochemical-mechanistic model Biome-BGC. The results from the two models are compared with filed observations form repeated permanent forest inventory plots of the Lime Stone National Park in Austria. The simulated CWD predictions of the BGC-model were compared with dead wood measurements (standing and lying dead wood) recorded at the permanent inventory plots. The inventory was established between 1994 and 1996 and remeasured from 2004 to 2005. For this analysis 40 plots of this inventory were selected which comprise the required dead wood components and are dominated by a single tree species. First we used the distance dependant individual tree growth model MOSES to derive the standing timber and the amount of mortality per hectare. MOSES is initialized with the inventory data at plot establishment and each sampling plot is treated as forest stand. The Biome-BGC is a process based biogeochemical model with extensions for Austrian tree species, a self initialization and a forest management tool. The initialization for the actual simulations with the BGC model was done as follows: We first used spin up runs to derive a balanced forest vegetation, similar to an undisturbed forest. Next we considered the management history of the past centuries (heavy clear cuts

High-Fidelity Roadway Modeling and Simulation

Science.gov (United States)

Wang, Jie; Papelis, Yiannis; Shen, Yuzhong; Unal, Ozhan; Cetin, Mecit

2010-01-01

Roads are an essential feature in our daily lives. With the advances in computing technologies, 2D and 3D road models are employed in many applications, such as computer games and virtual environments. Traditional road models were generated by professional artists manually using modeling software tools such as Maya and 3ds Max. This approach requires both highly specialized and sophisticated skills and massive manual labor. Automatic road generation based on procedural modeling can create road models using specially designed computer algorithms or procedures, reducing the tedious manual editing needed for road modeling dramatically. But most existing procedural modeling methods for road generation put emphasis on the visual effects of the generated roads, not the geometrical and architectural fidelity. This limitation seriously restricts the applicability of the generated road models. To address this problem, this paper proposes a high-fidelity roadway generation method that takes into account road design principles practiced by civil engineering professionals, and as a result, the generated roads can support not only general applications such as games and simulations in which roads are used as 3D assets, but also demanding civil engineering applications, which requires accurate geometrical models of roads. The inputs to the proposed method include road specifications, civil engineering road design rules, terrain information, and surrounding environment. Then the proposed method generates in real time 3D roads that have both high visual and geometrical fidelities. This paper discusses in details the procedures that convert 2D roads specified in shape files into 3D roads and civil engineering road design principles. The proposed method can be used in many applications that have stringent requirements on high precision 3D models, such as driving simulations and road design prototyping. Preliminary results demonstrate the effectiveness of the proposed method.

Modeling and Simulation for Safeguards

International Nuclear Information System (INIS)

Swinhoe, Martyn T.

2012-01-01

The purpose of this talk is to give an overview of the role of modeling and simulation in Safeguards R and 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.

A comparison of single column model simulations of summertime midlatitude continental convection

Energy Technology Data Exchange (ETDEWEB)

Ghan, Steven [Pacific Northwest National Laboratory, Richland, Washington (United States); Randall, David [Department of Atmospospheric Science, Colorado State University, Fort Collins, Colorado (United States); Xu, Kuan-Man [Department of Atmospospheric Science, Colorado State University, Fort Collins, Colorado (United States); Cederwall, Richard [Lawrence Livermore National Laboratory, Livermore, California (United States); Cripe, Douglas [Department of Atmospospheric Science, Colorado State University, Fort Collins, Colorado (United States); Hack, James [National Center for Atmospheric Research, Boulder, Colorado (United States); Iacobellis, Sam [Scripps Institution of Oceanography, University of California, La Jolla (United States); Klein, Stephen [Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey (United States); Krueger, Steven [Department of Meterology, University of Utah, Salt Lake City, Utah (United States); Lohmann, Ulrike [Department of Physics and Oceanography, Dalhousie University, Halifax, Nova Scotia (Canada)] (and others)

2000-01-27

Eleven different single-column models (SCMs) and one cloud ensemble model (CEM) are driven by boundary conditions observed at the Atmospheric Radiation Measurement (ARM) program southern Great Plains site for a 17 day period during the summer of 1995. Comparison of the model simulations reveals common signatures identifiable as products of errors in the boundary conditions. Intermodel differences in the simulated temperature, humidity, cloud, precipitation, and radiative fluxes reflect differences in model resolution or physical parameterizations, although sensitive dependence on initial conditions can also contribute to intermodel differences. All models perform well at times but poorly at others. Although none of the SCM simulations stands out as superior to the others, the simulation by the CEM is in several respects in better agreement with the observations than the simulations by the SCMs. Nudging of the simulated temperature and humidity toward observations generally improves the simulated cloud and radiation fields as well as the simulated temperature and humidity but degrades the precipitation simulation for models with large temperature and humidity biases without nudging. Although some of the intermodel differences have not been explained, others have been identified as model problems that can be or have been corrected as a result of the comparison. (c) 2000 American Geophysical Union.

A comparison of single column model simulations of summertime midlatitude continental convection

International Nuclear Information System (INIS)

Ghan, Steven; Randall, David; Xu, Kuan-Man; Cederwall, Richard; Cripe, Douglas; Hack, James; Iacobellis, Sam; Klein, Stephen; Krueger, Steven; Lohmann, Ulrike

2000-01-01

Eleven different single-column models (SCMs) and one cloud ensemble model (CEM) are driven by boundary conditions observed at the Atmospheric Radiation Measurement (ARM) program southern Great Plains site for a 17 day period during the summer of 1995. Comparison of the model simulations reveals common signatures identifiable as products of errors in the boundary conditions. Intermodel differences in the simulated temperature, humidity, cloud, precipitation, and radiative fluxes reflect differences in model resolution or physical parameterizations, although sensitive dependence on initial conditions can also contribute to intermodel differences. All models perform well at times but poorly at others. Although none of the SCM simulations stands out as superior to the others, the simulation by the CEM is in several respects in better agreement with the observations than the simulations by the SCMs. Nudging of the simulated temperature and humidity toward observations generally improves the simulated cloud and radiation fields as well as the simulated temperature and humidity but degrades the precipitation simulation for models with large temperature and humidity biases without nudging. Although some of the intermodel differences have not been explained, others have been identified as model problems that can be or have been corrected as a result of the comparison. (c) 2000 American Geophysical Union

Hybrid simulation models of production networks

CERN Document Server

Kouikoglou, Vassilis S

2001-01-01

This book is concerned with a most important area of industrial production, that of analysis and optimization of production lines and networks using discrete-event models and simulation. The book introduces a novel approach that combines analytic models and discrete-event simulation. Unlike conventional piece-by-piece simulation, this method observes a reduced number of events between which the evolution of the system is tracked analytically. Using this hybrid approach, several models are developed for the analysis of production lines and networks. The hybrid approach combines speed and accuracy for exceptional analysis of most practical situations. A number of optimization problems, involving buffer design, workforce planning, and production control, are solved through the use of hybrid models.

Comparison Of Simulation Results When Using Two Different Methods For Mold Creation In Moldflow Simulation

Directory of Open Access Journals (Sweden)

Kaushikbhai C. Parmar

2017-04-01

Full Text Available Simulation gives different results when using different methods for the same simulation. Autodesk Moldflow Simulation software provide two different facilities for creating mold for the simulation of injection molding process. Mold can be created inside the Moldflow or it can be imported as CAD file. The aim of this paper is to study the difference in the simulation results like mold temperature part temperature deflection in different direction time for the simulation and coolant temperature for this two different methods.

STEADY-STATE modeling and simulation of pipeline networks for compressible fluids

Directory of Open Access Journals (Sweden)

A.L.H. Costa

1998-12-01

Full Text Available This paper presents a model and an algorithm for the simulation of pipeline networks with compressible fluids. The model can predict pressures, flow rates, temperatures and gas compositions at any point of the network. Any network configuration can be simulated; the existence of cycles is not an obstacle. Numerical results from simulated data on a proposed network are shown for illustration. The potential of the simulator is explored by the analysis of a pressure relief network, using a stochastic procedure for the evaluation of system performance.

Simulation of MILD combustion using Perfectly Stirred Reactor model

KAUST Repository

Chen, Z.

2016-07-06

A simple model based on a Perfectly Stirred Reactor (PSR) is proposed for moderate or intense low-oxygen dilution (MILD) combustion. The PSR calculation is performed covering the entire flammability range and the tabulated chemistry approach is used with a presumed joint probability density function (PDF). The jet, in hot and diluted coflow experimental set-up under MILD conditions, is simulated using this reactor model for two oxygen dilution levels. The computed results for mean temperature, major and minor species mass fractions are compared with the experimental data and simulation results obtained recently using a multi-environment transported PDF approach. Overall, a good agreement is observed at three different axial locations for these comparisons despite the over-predicted peak value of CO formation. This suggests that MILD combustion can be effectively modelled by the proposed PSR model with lower computational cost.

Software-Engineering Process Simulation (SEPS) model

Science.gov (United States)

Lin, C. Y.; Abdel-Hamid, T.; Sherif, J. S.

1992-01-01

The Software Engineering Process Simulation (SEPS) model is described which was developed at JPL. SEPS is a dynamic simulation model of the software project development process. It uses the feedback principles of system dynamics to simulate the dynamic interactions among various software life cycle development activities and management decision making processes. The model is designed to be a planning tool to examine tradeoffs of cost, schedule, and functionality, and to test the implications of different managerial policies on a project's outcome. Furthermore, SEPS will enable software managers to gain a better understanding of the dynamics of software project development and perform postmodern assessments.

Modeling and simulation of a molten salt cavity receiver with Dymola

International Nuclear Information System (INIS)

Zhang, Qiangqiang; Li, Xin; Wang, Zhifeng; Zhang, Jinbai; El-Hefni, Baligh; Xu, Li

2015-01-01

Molten salt receivers play an important role in converting solar energy to thermal energy in concentrating solar power plants. This paper describes a dynamic mathematical model of the molten salt cavity receiver that couples the conduction, convection and radiation heat transfer processes in the receiver. The temperature dependence of the material properties is also considered. The radiosity method is used to calculate the radiation heat transfer inside the cavity. The outlet temperature of the receiver is calculated for 11 sets of transient working conditions. The simulation results compare well with experimental data, thus the model can be further used in system simulations of entire power plants. - Highlights: • A detailed model for molten salt cavity receiver is presented. • The model couples the conduction, convection and thermal radiation. • The simulation results compare well with experimental data. • The model can be further used for many purposes.

Tsunami simulation using submarine displacement calculated from simulation of ground motion due to seismic source model

Science.gov (United States)

Akiyama, S.; Kawaji, K.; Fujihara, S.

2013-12-01

difference calculation based on the shallow water theory. The initial wave height for tsunami generation is estimated from the vertical displacement of ocean bottom due to the crustal movements, which is obtained from the ground motion simulation mentioned above. The results of tsunami simulations are compared with the observations of the GPS wave gauges to evaluate the validity for the tsunami prediction using the fault model based on the seismic observation records.

Comparing the results of lattice and off-lattice simulations for the melt of nonconcatenated rings

International Nuclear Information System (INIS)

Halverson, Jonathan D; Kremer, Kurt; Grosberg, Alexander Y

2013-01-01

To study the conformational properties of unknotted and nonconcatenated ring polymers in the melt, we present a detailed qualitative and quantitative comparison of simulation data obtained by molecular dynamics simulation using an off-lattice bead-spring model and by Monte Carlo simulation using a lattice model. We observe excellent, and sometimes even unexpectedly good, agreement between the off-lattice and lattice results for many quantities measured including the gyration radii of the ring polymers, gyration radii of their subchains, contact probabilities, surface characteristics, number of contacts between subchains, and the static structure factors of the rings and their subchains. These results are, in part, put in contrast to Moore curves, and the open, linear polymer counterparts. While our analysis is extensive, our understanding of the ring melt conformations is still rather preliminary. (paper)

Cost Effective Community Based Dementia Screening: A Markov Model Simulation

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Erin Saito

2014-01-01

Full Text Available Background. Given the dementia epidemic and the increasing cost of healthcare, there is a need to assess the economic benefit of community based dementia screening programs. Materials and Methods. Markov model simulations were generated using data obtained from a community based dementia screening program over a one-year period. The models simulated yearly costs of caring for patients based on clinical transitions beginning in pre dementia and extending for 10 years. Results. A total of 93 individuals (74 female, 19 male were screened for dementia and 12 meeting clinical criteria for either mild cognitive impairment (n=7 or dementia (n=5 were identified. Assuming early therapeutic intervention beginning during the year of dementia detection, Markov model simulations demonstrated 9.8% reduction in cost of dementia care over a ten-year simulation period, primarily through increased duration in mild stages and reduced time in more costly moderate and severe stages. Discussion. Community based dementia screening can reduce healthcare costs associated with caring for demented individuals through earlier detection and treatment, resulting in proportionately reduced time in more costly advanced stages.

Validation of simulation models

DEFF Research Database (Denmark)

Rehman, Muniza; Pedersen, Stig Andur

2012-01-01

In philosophy of science, the interest for computational models and simulations has increased heavily during the past decades. Different positions regarding the validity of models have emerged but the views have not succeeded in capturing the diversity of validation methods. The wide variety...

Deterministic modelling and stochastic simulation of biochemical pathways using MATLAB.

Science.gov (United States)

Ullah, M; Schmidt, H; Cho, K H; Wolkenhauer, O

2006-03-01

The analysis of complex biochemical networks is conducted in two popular conceptual frameworks for modelling. The deterministic approach requires the solution of ordinary differential equations (ODEs, reaction rate equations) with concentrations as continuous state variables. The stochastic approach involves the simulation of differential-difference equations (chemical master equations, CMEs) with probabilities as variables. This is to generate counts of molecules for chemical species as realisations of random variables drawn from the probability distribution described by the CMEs. Although there are numerous tools available, many of them free, the modelling and simulation environment MATLAB is widely used in the physical and engineering sciences. We describe a collection of MATLAB functions to construct and solve ODEs for deterministic simulation and to implement realisations of CMEs for stochastic simulation using advanced MATLAB coding (Release 14). The program was successfully applied to pathway models from the literature for both cases. The results were compared to implementations using alternative tools for dynamic modelling and simulation of biochemical networks. The aim is to provide a concise set of MATLAB functions that encourage the experimentation with systems biology models. All the script files are available from www.sbi.uni-rostock.de/ publications_matlab-paper.html.

Illustrating Probability through Roulette: A Spreadsheet Simulation Model

Directory of Open Access Journals (Sweden)

Kala Chand Seal

2005-11-01

Full Text Available Teaching probability can be challenging because the mathematical formulas often are too abstract and complex for the students to fully grasp the underlying meaning and effect of the concepts. Games can provide a way to address this issue. For example, the game of roulette can be an exciting application for teaching probability concepts. In this paper, we implement a model of roulette in a spreadsheet that can simulate outcomes of various betting strategies. The simulations can be analyzed to gain better insights into the corresponding probability structures. We use the model to simulate a particular betting strategy known as the bet-doubling, or Martingale, strategy. This strategy is quite popular and is often erroneously perceived as a winning strategy even though the probability analysis shows that such a perception is incorrect. The simulation allows us to present the true implications of such a strategy for a player with a limited betting budget and relate the results to the underlying theoretical probability structure. The overall validation of the model, its use for teaching, including its application to analyze other types of betting strategies are discussed.

A pedagogical model for simulation-based learning in healthcare

Directory of Open Access Journals (Sweden)

Tuulikki Keskitalo

2015-11-01

Full Text Available The aim of this study was to design a pedagogical model for a simulation-based learning environment (SBLE in healthcare. Currently, simulation and virtual reality are a major focus in healthcare education. However, when and how these learning environments should be applied is not well-known. The present study tries to fill that gap. We pose the following research question: What kind of pedagogical model supports and facilitates students’ meaningful learning in SBLEs? The study used design-based research (DBR and case study approaches. We report the results from our second case study and how the pedagogical model was developed based on the lessons learned. The study involved nine facilitators and 25 students. Data were collected and analysed using mixed methods. The main result of this study is the refined pedagogical model. The model is based on the socio-cultural theory of learning and characteristics of meaningful learning as well as previous pedagogical models. The model will provide a more holistic and meaningful approach to teaching and learning in SBLEs. However, the model requires evidence and further development.

Numerical simulation of Higgs models

International Nuclear Information System (INIS)

Jaster, A.

1995-10-01

The SU(2) Higgs and the Schwinger model on the lattice were analysed. Numerical simulations of the SU(2) Higgs model were performed to study the finite temperature electroweak phase transition. With the help of the multicanonical method the distribution of an order parameter at the phase transition point was measured. This was used to obtain the order of the phase transition and the value of the interface tension with the histogram method. Numerical simulations were also performed at zero temperature to perform renormalization. The measured values for the Wilson loops were used to determine the static potential and from this the renormalized gauge coupling. The Schwinger model was simulated at different gauge couplings to analyse the properties of the Kaplan-Shamir fermions. The prediction that the mass parameter gets only multiplicative renormalization was tested and verified. (orig.)

Uterus models for use in virtual reality hysteroscopy simulators.

Science.gov (United States)

Niederer, Peter; Weiss, Stephan; Caduff, Rosmarie; Bajka, Michael; Szekély, Gabor; Harders, Matthias

2009-05-01

Virtual reality models of human organs are needed in surgery simulators which are developed for educational and training purposes. A simulation can only be useful, however, if the mechanical performance of the system in terms of force-feedback for the user as well as the visual representation is realistic. We therefore aim at developing a mechanical computer model of the organ in question which yields realistic force-deformation behavior under virtual instrument-tissue interactions and which, in particular, runs in real time. The modeling of the human uterus is described as it is to be implemented in a simulator for minimally invasive gynecological procedures. To this end, anatomical information which was obtained from specially designed computed tomography and magnetic resonance imaging procedures as well as constitutive tissue properties recorded from mechanical testing were used. In order to achieve real-time performance, the combination of mechanically realistic numerical uterus models of various levels of complexity with a statistical deformation approach is suggested. In view of mechanical accuracy of such models, anatomical characteristics including the fiber architecture along with the mechanical deformation properties are outlined. In addition, an approach to make this numerical representation potentially usable in an interactive simulation is discussed. The numerical simulation of hydrometra is shown in this communication. The results were validated experimentally. In order to meet the real-time requirements and to accommodate the large biological variability associated with the uterus, a statistical modeling approach is demonstrated to be useful.

Growth Kinetics of the Homogeneously Nucleated Water Droplets: Simulation Results

International Nuclear Information System (INIS)

Mokshin, Anatolii V; Galimzyanov, Bulat N

2012-01-01

The growth of homogeneously nucleated droplets in water vapor at the fixed temperatures T = 273, 283, 293, 303, 313, 323, 333, 343, 353, 363 and 373 K (the pressure p = 1 atm.) is investigated on the basis of the coarse-grained molecular dynamics simulation data with the mW-model. The treatment of simulation results is performed by means of the statistical method within the mean-first-passage-time approach, where the reaction coordinate is associated with the largest droplet size. It is found that the water droplet growth is characterized by the next features: (i) the rescaled growth law is unified at all the considered temperatures and (ii) the droplet growth evolves with acceleration and follows the power law.

Novel Methodology for Functional Modeling and Simulation of Wireless Embedded Systems

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Sosa Morales Emma

2008-01-01

Full Text Available Abstract A novel methodology is presented for the modeling and the simulation of wireless embedded systems. Tight interaction between the analog and the digital functionality makes the design and verification of such systems a real challenge. The applied methodology brings together the functional models of the baseband algorithms written in C language with the circuit descriptions at behavioral level in Verilog or Verilog-AMS for the system simulations in a single kernel environment. The physical layer of an ultrawideband system has been successfully modeled and simulated. The results confirm that this methodology provides a standardized framework in order to efficiently and accurately simulate complex mixed signal applications for embedded systems.

Experiments on the Model Testing of the 2nd Phase of Die Casting Process Compared with the Results of Numerical Simulation

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Dańko R.

2015-12-01

Full Text Available Experiments of filling the model moulds cavity of various inner shapes inserted in rectangular cavity of the casting die (dimensions: 280 mm (height × 190 mm (width × 10 mm (depth by applying model liquids of various density and viscosity are presented in the paper. Influence of die venting as well as inlet system area and inlet velocity on the volumetric rate of filling of the model liquid - achieved by means of filming the process in the system of a cold-chamber casting die was tested. Experiments compared with the results of simulation performed by means of the calculation module Novacast (Novaflow&Solid for the selected various casting conditions - are also presented in the paper.

Lithium-ion Battery Electrothermal Model, Parameter Estimation, and Simulation Environment

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Simone Orcioni

2017-03-01

Full Text Available The market for lithium-ion batteries is growing exponentially. The performance of battery cells is growing due to improving production technology, but market request is growing even more rapidly. Modeling and characterization of single cells and an efficient simulation environment is fundamental for the development of an efficient battery management system. The present work is devoted to defining a novel lumped electrothermal circuit of a single battery cell, the extraction procedure of the parameters of the single cell from experiments, and a simulation environment in SystemC-WMS for the simulation of a battery pack. The electrothermal model of the cell was validated against experimental measurements obtained in a climatic chamber. The model is then used to simulate a 48-cell battery, allowing statistical variations among parameters. The different behaviors of the cells in terms of state of charge, current, voltage, or heat flow rate can be observed in the results of the simulation environment.

Design and CFD Simulation of the Drift Eliminators in Comparison with PIV Results

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Stodůlka Jiří

2015-01-01

Full Text Available Drift eliminators are the essential part of all modern cooling towers preventing significant losses of liquid water escaping to the enviroment. These eliminators need to be effective in terms of water capture but on the other hand causing only minimal pressure loss as well. A new type of such eliminator was designed and numerically simulated using CFD tools. Results of the simulation are compared with PIV visulisation on the prototype model.

Reconstructing Holocene climate using a climate model: Model strategy and preliminary results

Science.gov (United States)

Haberkorn, K.; Blender, R.; Lunkeit, F.; Fraedrich, K.

2009-04-01

An Earth system model of intermediate complexity (Planet Simulator; PlaSim) is used to reconstruct Holocene climate based on proxy data. The Planet Simulator is a user friendly general circulation model (GCM) suitable for palaeoclimate research. Its easy handling and the modular structure allow for fast and problem dependent simulations. The spectral model is based on the moist primitive equations conserving momentum, mass, energy and moisture. Besides the atmospheric part, a mixed layer-ocean with sea ice and a land surface with biosphere are included. The present-day climate of PlaSim, based on an AMIP II control-run (T21/10L resolution), shows reasonable agreement with ERA-40 reanalysis data. Combining PlaSim with a socio-technological model (GLUES; DFG priority project INTERDYNAMIK) provides improved knowledge on the shift from hunting-gathering to agropastoral subsistence societies. This is achieved by a data assimilation approach, incorporating proxy time series into PlaSim to initialize palaeoclimate simulations during the Holocene. For this, the following strategy is applied: The sensitivities of the terrestrial PlaSim climate are determined with respect to sea surface temperature (SST) anomalies. Here, the focus is the impact of regionally varying SST both in the tropics and the Northern Hemisphere mid-latitudes. The inverse of these sensitivities is used to determine the SST conditions necessary for the nudging of land and coastal proxy climates. Preliminary results indicate the potential, the uncertainty and the limitations of the method.

Simulation of Mercury's magnetosheath with a combined hybrid-paraboloid model

Science.gov (United States)

Parunakian, David; Dyadechkin, Sergey; Alexeev, Igor; Belenkaya, Elena; Khodachenko, Maxim; Kallio, Esa; Alho, Markku

2017-08-01

In this paper we introduce a novel approach for modeling planetary magnetospheres that involves a combination of the hybrid model and the paraboloid magnetosphere model (PMM); we further refer to it as the combined hybrid model. While both of these individual models have been successfully applied in the past, their combination enables us both to overcome the traditional difficulties of hybrid models to develop a self-consistent magnetic field and to compensate the lack of plasma simulation in the PMM. We then use this combined model to simulate Mercury's magnetosphere and investigate the geometry and configuration of Mercury's magnetosheath controlled by various conditions in the interplanetary medium. The developed approach provides a unique comprehensive view of Mercury's magnetospheric environment for the first time. Using this setup, we compare the locations of the bow shock and the magnetopause as determined by simulations with the locations predicted by stand-alone PMM runs and also verify the magnetic and dynamic pressure balance at the magnetopause. We also compare the results produced by these simulations with observational data obtained by the magnetometer on board the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft along a dusk-dawn orbit and discuss the signatures of the magnetospheric features that appear in these simulations. Overall, our analysis suggests that combining the semiempirical PMM with a self-consistent global kinetic model creates new modeling possibilities which individual models cannot provide on their own.

A model selection support system for numerical simulations of nuclear thermal-hydraulics

International Nuclear Information System (INIS)

Gofuku, Akio; Shimizu, Kenji; Sugano, Keiji; Yoshikawa, Hidekazu; Wakabayashi, Jiro

1990-01-01

In order to execute efficiently a dynamic simulation of a large-scaled engineering system such as a nuclear power plant, it is necessary to develop intelligent simulation support system for all phases of the simulation. This study is concerned with the intelligent support for the program development phase and is engaged in the adequate model selection support method by applying AI (Artificial Intelligence) techniques to execute a simulation consistent with its purpose and conditions. A proto-type expert system to support the model selection for numerical simulations of nuclear thermal-hydraulics in the case of cold leg small break loss-of-coolant accident of PWR plant is now under development on a personal computer. The steps to support the selection of both fluid model and constitutive equations for the drift flux model have been developed. Several cases of model selection were carried out and reasonable model selection results were obtained. (author)

A Comparison of Two Land Use Simulation Models under the RCP4.5 Scenario in China

Directory of Open Access Journals (Sweden)

Feng Wu

2013-01-01

Full Text Available The land use simulation model is an important tool to analyze the land use/land cover change (LUCC, which plays a key role in influencing the global warming. However, there have been very few global LUCC simulation models, especially the models that can be used to analyze the interaction among the socioeconomic development, climate change, and LUCC. The Global Change Assessment Model (GCAM and the GTAP-AEZ model are two models that take account of the influence of social economy and climate change at the global scale, but they may have some parameter errors due to the rough parameter setting. This study aims to compare the simulation results obtained with the GCAM model and GTAP-AEZ model and optimize their parameters according to the specific conditions of China. First, we simulated the land use structure in China in 2010 with the two models and compared the simulation results with the real one. Second, we calibrated these parameters of models according to the China’s national conditions and implemented the simulation again. The result indicates that the calibrated GCAM can provide more accurate simulation result of land use, which can provide significant reference information for the land use planning and policy formulation to mitigate the climate change in China.

Hydrodynamic modeling of petroleum reservoirs using simulator MUFITS

Science.gov (United States)

Afanasyev, Andrey

2015-04-01

MUFITS is new noncommercial software for numerical modeling of subsurface processes in various applications (www.mufits.imec.msu.ru). To this point, the simulator was used for modeling nonisothermal flows in geothermal reservoirs and for modeling underground carbon dioxide storage. In this work, we present recent extension of the code to petroleum reservoirs. The simulator can be applied in conventional black oil modeling, but it also utilizes a more complicated models for volatile oil and gas condensate reservoirs as well as for oil rim fields. We give a brief overview of the code by providing the description of internal representation of reservoir models, which are constructed of grid blocks, interfaces, stock tanks as well as of pipe segments and pipe junctions for modeling wells and surface networks. For conventional black oil approach, we present the simulation results for SPE comparative tests. We propose an accelerated compositional modeling method for sub- and supercritical flows subjected to various phase equilibria, particularly to three-phase equilibria of vapour-liquid-liquid type. The method is based on the calculation of the thermodynamic potential of reservoir fluid as a function of pressure, total enthalpy and total composition and storing its values as a spline table, which is used in hydrodynamic simulation for accelerated PVT properties prediction. We provide the description of both the spline calculation procedure and the flashing algorithm. We evaluate the thermodynamic potential for a mixture of two pseudo-components modeling the heavy and light hydrocarbon fractions. We develop a technique for converting black oil PVT tables to the potential, which can be used for in-situ hydrocarbons multiphase equilibria prediction under sub- and supercritical conditions, particularly, in gas condensate and volatile oil reservoirs. We simulate recovery from a reservoir subject to near-critical initial conditions for hydrocarbon mixture. We acknowledge

Implications of the Abolition of Milk Quota System for Polish Agriculture – Simulation Results Based on the AG MEMOD Model

Directory of Open Access Journals (Sweden)

Mariusz Hamulczuk

2009-09-01

Full Text Available The objective of the study was to asses the economics effects of the dairy policy reform sanctioned by CAP Health Check on the agricultural market in Poland. The paper presents a theoretical study of the production control program as well as a model based quantitative analysis of the implications of the reform on the agricultural markets. The partial equilibrium model AGMEMOD was used for simulation. The results obtained indicate that the expansion and subsequently the elimination of milk quota system lead to the growth of milk production and consumption in Poland which confirms the hypothesis derived from theoretical study. As a consequence, the growth of the production of most of dairy products and the decrease of their prices is expected. As the growth of dairy consumption is smaller than the growth of milk production the increase of self-sufficiency in the dairy market is predicted. The comparison of the scale of price adjustment resulting from the dairy reform to the market price changes observed recently leads to the conclusion that global market factors will probably be more important for the future development of milk production and prices in Poland than the milk quota abolition. Nevertheless, the reform constitutes a significant change in business conditions for producers and consumers of milk and dairy products. As a consequence, milk production will become more market based, as far as market prices, production costs and milk yields are concerned. Simulation results from the AGMEMOD model confirm the opinion brought by other authors that the abolition of milk quotas will lead to the decline of dairy farmer income. The main beneficiaries of the reform would become the consumers who could take advantage of the decline in prices of the dairy products.

Simulations of an Offshore Wind Farm Using Large-Eddy Simulation and a Torque-Controlled Actuator Disc Model

Science.gov (United States)

Creech, Angus; Früh, Wolf-Gerrit; Maguire, A. Eoghan

2015-05-01

We present here a computational fluid dynamics (CFD) simulation of Lillgrund offshore wind farm, which is located in the Øresund Strait between Sweden and Denmark. The simulation combines a dynamic representation of wind turbines embedded within a large-eddy simulation CFD solver and uses hr-adaptive meshing to increase or decrease mesh resolution where required. This allows the resolution of both large-scale flow structures around the wind farm, and the local flow conditions at individual turbines; consequently, the response of each turbine to local conditions can be modelled, as well as the resulting evolution of the turbine wakes. This paper provides a detailed description of the turbine model which simulates the interaction between the wind, the turbine rotors, and the turbine generators by calculating the forces on the rotor, the body forces on the air, and instantaneous power output. This model was used to investigate a selection of key wind speeds and directions, investigating cases where a row of turbines would be fully aligned with the wind or at specific angles to the wind. Results shown here include presentations of the spin-up of turbines, the observation of eddies moving through the turbine array, meandering turbine wakes, and an extensive wind farm wake several kilometres in length. The key measurement available for cross-validation with operational wind farm data is the power output from the individual turbines, where the effect of unsteady turbine wakes on the performance of downstream turbines was a main point of interest. The results from the simulations were compared to the performance measurements from the real wind farm to provide a firm quantitative validation of this methodology. Having achieved good agreement between the model results and actual wind farm measurements, the potential of the methodology to provide a tool for further investigations of engineering and atmospheric science problems is outlined.

On Improving 4-km Mesoscale Model Simulations

Science.gov (United States)

Deng, Aijun; Stauffer, David R.

2006-03-01

A previous study showed that use of analysis-nudging four-dimensional data assimilation (FDDA) and improved physics in the fifth-generation Pennsylvania State University National Center for Atmospheric Research Mesoscale Model (MM5) produced the best overall performance on a 12-km-domain simulation, based on the 18 19 September 1983 Cross-Appalachian Tracer Experiment (CAPTEX) case. However, reducing the simulated grid length to 4 km had detrimental effects. The primary cause was likely the explicit representation of convection accompanying a cold-frontal system. Because no convective parameterization scheme (CPS) was used, the convective updrafts were forced on coarser-than-realistic scales, and the rainfall and the atmospheric response to the convection were too strong. The evaporative cooling and downdrafts were too vigorous, causing widespread disruption of the low-level winds and spurious advection of the simulated tracer. In this study, a series of experiments was designed to address this general problem involving 4-km model precipitation and gridpoint storms and associated model sensitivities to the use of FDDA, planetary boundary layer (PBL) turbulence physics, grid-explicit microphysics, a CPS, and enhanced horizontal diffusion. Some of the conclusions include the following: 1) Enhanced parameterized vertical mixing in the turbulent kinetic energy (TKE) turbulence scheme has shown marked improvements in the simulated fields. 2) Use of a CPS on the 4-km grid improved the precipitation and low-level wind results. 3) Use of the Hong and Pan Medium-Range Forecast PBL scheme showed larger model errors within the PBL and a clear tendency to predict much deeper PBL heights than the TKE scheme. 4) Combining observation-nudging FDDA with a CPS produced the best overall simulations. 5) Finer horizontal resolution does not always produce better simulations, especially in convectively unstable environments, and a new CPS suitable for 4-km resolution is needed. 6

Dynamic Simulation of Human Gait Model With Predictive Capability.

Science.gov (United States)

Sun, Jinming; Wu, Shaoli; Voglewede, Philip A

2018-03-01

In this paper, it is proposed that the central nervous system (CNS) controls human gait using a predictive control approach in conjunction with classical feedback control instead of exclusive classical feedback control theory that controls based on past error. To validate this proposition, a dynamic model of human gait is developed using a novel predictive approach to investigate the principles of the CNS. The model developed includes two parts: a plant model that represents the dynamics of human gait and a controller that represents the CNS. The plant model is a seven-segment, six-joint model that has nine degrees-of-freedom (DOF). The plant model is validated using data collected from able-bodied human subjects. The proposed controller utilizes model predictive control (MPC). MPC uses an internal model to predict the output in advance, compare the predicted output to the reference, and optimize the control input so that the predicted error is minimal. To decrease the complexity of the model, two joints are controlled using a proportional-derivative (PD) controller. The developed predictive human gait model is validated by simulating able-bodied human gait. The simulation results show that the developed model is able to simulate the kinematic output close to experimental data.

Improvement of Cycle Dependent Core Model for NPP Simulator

International Nuclear Information System (INIS)

Song, J. S.; Koo, B. S.; Kim, H. Y. and others

2003-11-01

The purpose of this study is to establish automatic core model generation system and to develop 4 cycle real time core analysis methodology with 5% power distribution and 500 pcm reactivity difference criteria for nuclear power plant simulator. The standardized procedure to generate database from ROCS and ANC, which are used for domestic PWR core design, was established for the cycle specific simulator core model generation. An automatic data interface system to generate core model also established. The system includes ARCADIS which edits group constant and DHCGEN which generates interface coupling coefficient correction database. The interface coupling coefficient correction method developed in this study has 4 cycle real time capability and accuracies of which the maximum differences between core design results are within 103 pcm reactivity, 1% relative power distribution and 6% control rod worth. A nuclear power plant core simulation program R-MASTER was developed using the methodology and applied by the concept of distributed client system in simulator. The performance was verified by site acceptance test in Simulator no. 2 in Kori Training Center for 30 initial condition generation and 27 steady state, transient and postulated accident situations

Improvement of Cycle Dependent Core Model for NPP Simulator

Energy Technology Data Exchange (ETDEWEB)

Song, J. S.; Koo, B. S.; Kim, H. Y. and others

2003-11-15

The purpose of this study is to establish automatic core model generation system and to develop 4 cycle real time core analysis methodology with 5% power distribution and 500 pcm reactivity difference criteria for nuclear power plant simulator. The standardized procedure to generate database from ROCS and ANC, which are used for domestic PWR core design, was established for the cycle specific simulator core model generation. An automatic data interface system to generate core model also established. The system includes ARCADIS which edits group constant and DHCGEN which generates interface coupling coefficient correction database. The interface coupling coefficient correction method developed in this study has 4 cycle real time capability and accuracies of which the maximum differences between core design results are within 103 pcm reactivity, 1% relative power distribution and 6% control rod worth. A nuclear power plant core simulation program R-MASTER was developed using the methodology and applied by the concept of distributed client system in simulator. The performance was verified by site acceptance test in Simulator no. 2 in Kori Training Center for 30 initial condition generation and 27 steady state, transient and postulated accident situations.

Dynamic simulation of sustainable farm development scenarios using cognitive modeling

Directory of Open Access Journals (Sweden)

Tuzhyk Kateryna

2017-03-01

Full Text Available Dynamic simulation of sustainable farm development scenarios using cognitive modeling. The paper presents a dynamic simulation system of sustainable development scenarios on farms using cognitive modeling. The system incorporates relevant variables which affect the sustainable development of farms. Its user provides answers to strategic issues connected with the level of farm sustainability over a long-term perspective of dynamic development. The work contains a description of the model structure as well as the results of simulations carried out on 16 farms in northern Ukraine. The results show that the process of sustainability is based mainly on the potential for innovation in agricultural production and biodiversity. The user is able to simulate various scenarios for the sustainable development of a farm and visualize the influence of factors on the economic and social situation, as well as on environmental aspects. Upon carrying out a series of simulations, it was determined that the development of farms characterized by sustainable development is based on additional profit, which serves as the main motivation for transforming a conventional farm into a sustainable one. Nevertheless, additional profit is not the only driving force in the system of sustainable development. The standard of living, market condition, and legal regulations as well as government support also play a significant motivational role.

Flood simulation model using XP-SWMM along Terengganu River ...

African Journals Online (AJOL)

Malaysia is one of the tropical countries in the world with heavy rainfall throughout the year and floods are the most common disaster in Malaysia. Flood simulation model was carried out along Terengganu River for dry and rainy seasons. The result of the simulation shows the water level reached its maximum level at the 1st ...

Simulation of a G-tolerance curve using the pulsatile cardiovascular model

Science.gov (United States)

Solomon, M.; Srinivasan, R.

1985-01-01

A computer simulation study, performed to assess the ability of the cardiovascular model to reproduce the G tolerance curve (G level versus tolerance time) is reported. A composite strength duration curve derived from experimental data obtained in human centrifugation studies was used for comparison. The effects of abolishing automomic control and of blood volume loss on G tolerance were also simulated. The results provide additional validation of the model. The need for the presence of autonomic reflexes even at low levels of G is pointed out. The low margin of safety with a loss of blood volume indicated by the simulation results underscores the necessity for protective measures during Shuttle reentry.

Comparison of multiple-criteria decision-making methods - results of simulation study

Directory of Open Access Journals (Sweden)

Michał Adamczak

2016-12-01

Full Text Available Background: Today, both researchers and practitioners have many methods for supporting the decision-making process. Due to the conditions in which supply chains function, the most interesting are multi-criteria methods. The use of sophisticated methods for supporting decisions requires the parameterization and execution of calculations that are often complex. So is it efficient to use sophisticated methods? Methods: The authors of the publication compared two popular multi-criteria decision-making methods: the  Weighted Sum Model (WSM and the Analytic Hierarchy Process (AHP. A simulation study reflects these two decision-making methods. Input data for this study was a set of criteria weights and the value of each in terms of each criterion. Results: The iGrafx Process for Six Sigma simulation software recreated how both multiple-criteria decision-making methods (WSM and AHP function. The result of the simulation was a numerical value defining the preference of each of the alternatives according to the WSM and AHP methods. The alternative producing a result of higher numerical value  was considered preferred, according to the selected method. In the analysis of the results, the relationship between the values of the parameters and the difference in the results presented by both methods was investigated. Statistical methods, including hypothesis testing, were used for this purpose. Conclusions: The simulation study findings prove that the results obtained with the use of two multiple-criteria decision-making methods are very similar. Differences occurred more frequently in lower-value parameters from the "value of each alternative" group and higher-value parameters from the "weight of criteria" group.

Simulation - modeling - experiment; Simulation - modelisation - experience

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-07-01

After two workshops held in 2001 on the same topics, and in order to make a status of the advances in the domain of simulation and measurements, the main goals proposed for this workshop are: the presentation of the state-of-the-art of tools, methods and experiments in the domains of interest of the Gedepeon research group, the exchange of information about the possibilities of use of computer codes and facilities, about the understanding of physical and chemical phenomena, and about development and experiment needs. This document gathers 18 presentations (slides) among the 19 given at this workshop and dealing with: the deterministic and stochastic codes in reactor physics (Rimpault G.); MURE: an evolution code coupled with MCNP (Meplan O.); neutronic calculation of future reactors at EdF (Lecarpentier D.); advance status of the MCNP/TRIO-U neutronic/thermal-hydraulics coupling (Nuttin A.); the FLICA4/TRIPOLI4 thermal-hydraulics/neutronics coupling (Aniel S.); methods of disturbances and sensitivity analysis of nuclear data in reactor physics, application to VENUS-2 experimental reactor (Bidaud A.); modeling for the reliability improvement of an ADS accelerator (Biarotte J.L.); residual gas compensation of the space charge of intense beams (Ben Ismail A.); experimental determination and numerical modeling of phase equilibrium diagrams of interest in nuclear applications (Gachon J.C.); modeling of irradiation effects (Barbu A.); elastic limit and irradiation damage in Fe-Cr alloys: simulation and experiment (Pontikis V.); experimental measurements of spallation residues, comparison with Monte-Carlo simulation codes (Fallot M.); the spallation target-reactor coupling (Rimpault G.); tools and data (Grouiller J.P.); models in high energy transport codes: status and perspective (Leray S.); other ways of investigation for spallation (Audoin L.); neutrons and light particles production at intermediate energies (20-200 MeV) with iron, lead and uranium targets (Le Colley F

Comparing reconstructed past variations and future projections of the Baltic Sea ecosystem—first results from multi-model ensemble simulations

International Nuclear Information System (INIS)

Meier, H E Markus; Andersson, Helén C; Arheimer, Berit; Donnelly, Chantal; Eilola, Kari; Höglund, Anders; Kuznetsov, Ivan; Blenckner, Thorsten; Gustafsson, Bo G; Müller-Karulis, Bärbel; Niiranen, Susa; Chubarenko, Boris; Hansson, Anders; Havenhand, Jonathan; MacKenzie, Brian R; Neumann, Thomas; Piwowarczyk, Joanna; Raudsepp, Urmas; Reckermann, Marcus; Ruoho-Airola, Tuija

2012-01-01

Multi-model ensemble simulations for the marine biogeochemistry and food web of the Baltic Sea were performed for the period 1850–2098, and projected changes in the future climate were compared with the past climate environment. For the past period 1850–2006, atmospheric, hydrological and nutrient forcings were reconstructed, based on historical measurements. For the future period 1961–2098, scenario simulations were driven by regionalized global general circulation model (GCM) data and forced by various future greenhouse gas emission and air- and riverborne nutrient load scenarios (ranging from a pessimistic ‘business-as-usual’ to the most optimistic case). To estimate uncertainties, different models for the various parts of the Earth system were applied. Assuming the IPCC greenhouse gas emission scenarios A1B or A2, we found that water temperatures at the end of this century may be higher and salinities and oxygen concentrations may be lower than ever measured since 1850. There is also a tendency of increased eutrophication in the future, depending on the nutrient load scenario. Although cod biomass is mainly controlled by fishing mortality, climate change together with eutrophication may result in a biomass decline during the latter part of this century, even when combined with lower fishing pressure. Despite considerable shortcomings of state-of-the-art models, this study suggests that the future Baltic Sea ecosystem may unprecedentedly change compared to the past 150 yr. As stakeholders today pay only little attention to adaptation and mitigation strategies, more information is needed to raise public awareness of the possible impacts of climate change on marine ecosystems. (letter)

Research on Francis Turbine Modeling for Large Disturbance Hydropower Station Transient Process Simulation

Directory of Open Access Journals (Sweden)

Guangtao Zhang

2015-01-01

Full Text Available In the field of hydropower station transient process simulation (HSTPS, characteristic graph-based iterative hydroturbine model (CGIHM has been widely used when large disturbance hydroturbine modeling is involved. However, by this model, iteration should be used to calculate speed and pressure, and slow convergence or no convergence problems may be encountered for some reasons like special characteristic graph profile, inappropriate iterative algorithm, or inappropriate interpolation algorithm, and so forth. Also, other conventional large disturbance hydroturbine models are of some disadvantages and difficult to be used widely in HSTPS. Therefore, to obtain an accurate simulation result, a simple method for hydroturbine modeling is proposed. By this method, both the initial operating point and the transfer coefficients of linear hydroturbine model keep changing during simulation. Hence, it can reflect the nonlinearity of the hydroturbine and be used for Francis turbine simulation under large disturbance condition. To validate the proposed method, both large disturbance and small disturbance simulations of a single hydrounit supplying a resistive, isolated load were conducted. It was shown that the simulation result is consistent with that of field test. Consequently, the proposed method is an attractive option for HSTPS involving Francis turbine modeling under large disturbance condition.

3D Core Model for simulation of nuclear power plants: Simulation requirements, model features, and validation

International Nuclear Information System (INIS)

Zerbino, H.

1999-01-01

In 1994-1996, Thomson Training and Simulation (TT and S) earned out the D50 Project, which involved the design and construction of optimized replica simulators for one Dutch and three German Nuclear Power Plants. It was recognized early on that the faithful reproduction of the Siemens reactor control and protection systems would impose extremely stringent demands on the simulation models, particularly the Core physics and the RCS thermohydraulics. The quality of the models, and their thorough validation, were thus essential. The present paper describes the main features of the fully 3D Core model implemented by TT and S, and its extensive validation campaign, which was defined in extremely positive collaboration with the Customer and the Core Data suppliers. (author)

A study for production simulation model generation system based on data model at a shipyard

Directory of Open Access Journals (Sweden)

Myung-Gi Back

2016-09-01

Full Text Available Simulation technology is a type of shipbuilding product lifecycle management solution used to support production planning or decision-making. Normally, most shipbuilding processes are consisted of job shop production, and the modeling and simulation require professional skills and experience on shipbuilding. For these reasons, many shipbuilding companies have difficulties adapting simulation systems, regardless of the necessity for the technology. In this paper, the data model for shipyard production simulation model generation was defined by analyzing the iterative simulation modeling procedure. The shipyard production simulation data model defined in this study contains the information necessary for the conventional simulation modeling procedure and can serve as a basis for simulation model generation. The efficacy of the developed system was validated by applying it to the simulation model generation of the panel block production line. By implementing the initial simulation model generation process, which was performed in the past with a simulation modeler, the proposed system substantially reduced the modeling time. In addition, by reducing the difficulties posed by different modeler-dependent generation methods, the proposed system makes the standardization of the simulation model quality possible.

Validation process of simulation model

International Nuclear Information System (INIS)

San Isidro, M. J.

1998-01-01

It is presented a methodology on empirical validation about any detailed simulation model. This king of validation it is always related with an experimental case. The empirical validation has a residual sense, because the conclusions are based on comparisons between simulated outputs and experimental measurements. This methodology will guide us to detect the fails of the simulation model. Furthermore, it can be used a guide in the design of posterior experiments. Three steps can be well differentiated: Sensitivity analysis. It can be made with a DSA, differential sensitivity analysis, and with a MCSA, Monte-Carlo sensitivity analysis. Looking the optimal domains of the input parameters. It has been developed a procedure based on the Monte-Carlo methods and Cluster techniques, to find the optimal domains of these parameters. Residual analysis. This analysis has been made on the time domain and on the frequency domain, it has been used the correlation analysis and spectral analysis. As application of this methodology, it is presented the validation carried out on a thermal simulation model on buildings, Esp., studying the behavior of building components on a Test Cell of LECE of CIEMAT. (Author) 17 refs

Modeling, Simulation and Position Control of 3 Degree of Freedom Articulated Manipulator

Directory of Open Access Journals (Sweden)

Hossein Sadegh Lafmejani

2013-09-01

Full Text Available In this paper, the modeling, simulation and control of 3 degree of freedom articulated robotic manipulator have been studied. First, we extracted kinematics and dynamics equations of the mentioned manipulator by using the Lagrange method. In order to validate the analytical model of the manipulator we compared the model simulated in the simulation environment of Matlab with the model was simulated with the SimMechanics toolbox. A sample path has been designed for analyzing the tracking subject. The system has been linearized with feedback linearization and then a PID controller was applied to track a reference trajectory. Finally, the control results have been compared with a nonlinear PID controller.

Simulations of the Mid-Pliocene Warm Period Using Two Versions of the NASA-GISS ModelE2-R Coupled Model

Science.gov (United States)

Chandler, M. A.; Sohl, L. E.; Jonas, J. A.; Dowsett, H. J.; Kelley, M.

2013-01-01

The mid-Pliocene Warm Period (mPWP) bears many similarities to aspects of future global warming as projected by the Intergovernmental Panel on Climate Change (IPCC, 2007). Both marine and terrestrial data point to high-latitude temperature amplification, including large decreases in sea ice and land ice, as well as expansion of warmer climate biomes into higher latitudes. Here we present our most recent simulations of the mid-Pliocene climate using the CMIP5 version of the NASAGISS Earth System Model (ModelE2-R). We describe the substantial impact associated with a recent correction made in the implementation of the Gent-McWilliams ocean mixing scheme (GM), which has a large effect on the simulation of ocean surface temperatures, particularly in the North Atlantic Ocean. The effect of this correction on the Pliocene climate results would not have been easily determined from examining its impact on the preindustrial runs alone, a useful demonstration of how the consequences of code improvements as seen in modern climate control runs do not necessarily portend the impacts in extreme climates.Both the GM-corrected and GM-uncorrected simulations were contributed to the Pliocene Model Intercomparison Project (PlioMIP) Experiment 2. Many findings presented here corroborate results from other PlioMIP multi-model ensemble papers, but we also emphasize features in the ModelE2-R simulations that are unlike the ensemble means. The corrected version yields results that more closely resemble the ocean core data as well as the PRISM3D reconstructions of the mid-Pliocene, especially the dramatic warming in the North Atlantic and Greenland-Iceland-Norwegian Sea, which in the new simulation appears to be far more realistic than previously found with older versions of the GISS model. Our belief is that continued development of key physical routines in the atmospheric model, along with higher resolution and recent corrections to mixing parameterisations in the ocean model, have led

Validation of advanced NSSS simulator model for loss-of-coolant accidents

Energy Technology Data Exchange (ETDEWEB)

Kao, S.P.; Chang, S.K.; Huang, H.C. [Nuclear Training Branch, Northeast Utilities, Waterford, CT (United States)

1995-09-01

The replacement of the NSSS (Nuclear Steam Supply System) model on the Millstone 2 full-scope simulator has significantly increased its fidelity to simulate adverse conditions in the RCS. The new simulator NSSS model is a real-time derivative of the Nuclear Plant Analyzer by ABB. The thermal-hydraulic model is a five-equation, non-homogeneous model for water, steam, and non-condensible gases. The neutronic model is a three-dimensional nodal diffusion model. In order to certify the new NSSS model for operator training, an extensive validation effort has been performed by benchmarking the model performance against RELAP5/MOD2. This paper presents the validation results for the cases of small-and large-break loss-of-coolant accidents (LOCA). Detailed comparisons in the phenomena of reflux-condensation, phase separation, and two-phase natural circulation are discussed.

FINAL SIMULATION RESULTS FOR DEMONSTRATION CASE 1 AND 2

Energy Technology Data Exchange (ETDEWEB)

David Sloan; Woodrow Fiveland

2003-10-15

The goal of this DOE Vision-21 project work scope was to develop an integrated suite of software tools that could be used to simulate and visualize advanced plant concepts. Existing process simulation software did not meet the DOE's objective of ''virtual simulation'' which was needed to evaluate complex cycles. The overall intent of the DOE was to improve predictive tools for cycle analysis, and to improve the component models that are used in turn to simulate equipment in the cycle. Advanced component models are available; however, a generic coupling capability that would link the advanced component models to the cycle simulation software remained to be developed. In the current project, the coupling of the cycle analysis and cycle component simulation software was based on an existing suite of programs. The challenge was to develop a general-purpose software and communications link between the cycle analysis software Aspen Plus{reg_sign} (marketed by Aspen Technology, Inc.), and specialized component modeling packages, as exemplified by industrial proprietary codes (utilized by ALSTOM Power Inc.) and the FLUENT{reg_sign} computational fluid dynamics (CFD) code (provided by Fluent Inc). A software interface and controller, based on an open CAPE-OPEN standard, has been developed and extensively tested. Various test runs and demonstration cases have been utilized to confirm the viability and reliability of the software. ALSTOM Power was tasked with the responsibility to select and run two demonstration cases to test the software--(1) a conventional steam cycle (designated as Demonstration Case 1), and (2) a combined cycle test case (designated as Demonstration Case 2). Demonstration Case 1 is a 30 MWe coal-fired power plant for municipal electricity generation, while Demonstration Case 2 is a 270 MWe, natural gas-fired, combined cycle power plant. Sufficient data was available from the operation of both power plants to complete the cycle

Utilization of Short-Simulations for Tuning High-Resolution Climate Model

Science.gov (United States)

Lin, W.; Xie, S.; Ma, P. L.; Rasch, P. J.; Qian, Y.; Wan, H.; Ma, H. Y.; Klein, S. A.

2016-12-01

Many physical parameterizations in atmospheric models are sensitive to resolution. Tuning the models that involve a multitude of parameters at high resolution is computationally expensive, particularly when relying primarily on multi-year simulations. This work describes a complementary set of strategies for tuning high-resolution atmospheric models, using ensembles of short simulations to reduce the computational cost and elapsed time. Specifically, we utilize the hindcast approach developed through the DOE Cloud Associated Parameterization Testbed (CAPT) project for high-resolution model tuning, which is guided by a combination of short (tests have been found to be effective in numerous previous studies in identifying model biases due to parameterized fast physics, and we demonstrate that it is also useful for tuning. After the most egregious errors are addressed through an initial "rough" tuning phase, longer simulations are performed to "hone in" on model features that evolve over longer timescales. We explore these strategies to tune the DOE ACME (Accelerated Climate Modeling for Energy) model. For the ACME model at 0.25° resolution, it is confirmed that, given the same parameters, major biases in global mean statistics and many spatial features are consistent between Atmospheric Model Intercomparison Project (AMIP)-type simulations and CAPT-type hindcasts, with just a small number of short-term simulations for the latter over the corresponding season. The use of CAPT hindcasts to find parameter choice for the reduction of large model biases dramatically improves the turnaround time for the tuning at high resolution. Improvement seen in CAPT hindcasts generally translates to improved AMIP-type simulations. An iterative CAPT-AMIP tuning approach is therefore adopted during each major tuning cycle, with the former to survey the likely responses and narrow the parameter space, and the latter to verify the results in climate context along with assessment in

Integrated Water Resources Simulation Model for Rural Community

Science.gov (United States)

Li, Y.-H.; Liao, W.-T.; Tung, C.-P.

2012-04-01

The purpose of this study is to develop several water resources simulation models for residence houses, constructed wetlands and farms and then integrate these models for a rural community. Domestic and irrigation water uses are the major water demand in rural community. To build up a model estimating domestic water demand for residence houses, the average water use per person per day should be accounted first, including water uses of kitchen, bathroom, toilet and laundry. On the other hand, rice is the major crop in the study region, and its productive efficiency sometimes depends on the quantity of irrigation water. The water demand can be estimated by crop water use, field leakage and water distribution loss. Irrigation water comes from rainfall, water supply system and reclaimed water which treated by constructed wetland. In recent years, constructed wetlands play an important role in water resources recycle. They can purify domestic wastewater for water recycling and reuse. After treating from constructed wetlands, the reclaimed water can be reused in washing toilets, watering gardens and irrigating farms. Constructed wetland is one of highly economic benefits for treating wastewater through imitating the processing mechanism of natural wetlands. In general, the treatment efficiency of constructed wetlands is determined by evapotranspiration, inflow, and water temperature. This study uses system dynamics modeling to develop models for different water resource components in a rural community. Furthermore, these models are integrated into a whole system. The model not only is utilized to simulate how water moves through different components, including residence houses, constructed wetlands and farms, but also evaluates the efficiency of water use. By analyzing the flow of water, the water resource simulation model can optimizes water resource distribution under different scenarios, and the result can provide suggestions for designing water resource system of a

Plasma modelling and numerical simulation

International Nuclear Information System (INIS)

Van Dijk, J; Kroesen, G M W; Bogaerts, A

2009-01-01

Plasma modelling is an exciting subject in which virtually all physical disciplines are represented. Plasma models combine the electromagnetic, statistical and fluid dynamical theories that have their roots in the 19th century with the modern insights concerning the structure of matter that were developed throughout the 20th century. The present cluster issue consists of 20 invited contributions, which are representative of the state of the art in plasma modelling and numerical simulation. These contributions provide an in-depth discussion of the major theories and modelling and simulation strategies, and their applications to contemporary plasma-based technologies. In this editorial review, we introduce and complement those papers by providing a bird's eye perspective on plasma modelling and discussing the historical context in which it has surfaced. (editorial review)

Improved Path Loss Simulation Incorporating Three-Dimensional Terrain Model Using Parallel Coprocessors

Directory of Open Access Journals (Sweden)

Zhang Bin Loo

2017-01-01

Full Text Available Current network simulators abstract out wireless propagation models due to the high computation requirements for realistic modeling. As such, there is still a large gap between the results obtained from simulators and real world scenario. In this paper, we present a framework for improved path loss simulation built on top of an existing network simulation software, NS-3. Different from the conventional disk model, the proposed simulation also considers the diffraction loss computed using Epstein and Peterson’s model through the use of actual terrain elevation data to give an accurate estimate of path loss between a transmitter and a receiver. The drawback of high computation requirements is relaxed by offloading the computationally intensive components onto an inexpensive off-the-shelf parallel coprocessor, which is a NVIDIA GPU. Experiments are performed using actual terrain elevation data provided from United States Geological Survey. As compared to the conventional CPU architecture, the experimental result shows that a speedup of 20x to 42x is achieved by exploiting the parallel processing of GPU to compute the path loss between two nodes using terrain elevation data. The result shows that the path losses between two nodes are greatly affected by the terrain profile between these two nodes. Besides this, the result also suggests that the common strategy to place the transmitter in the highest position may not always work.

NASA Standard for Models and Simulations: Philosophy and Requirements Overview

Science.gov (United States)

Blattnig, Steve R.; Luckring, James M.; Morrison, Joseph H.; Sylvester, Andre J.; Tripathi, Ram K.; Zang, Thomas A.

2013-01-01

Following the Columbia Accident Investigation Board report, the NASA Administrator chartered an executive team (known as the Diaz Team) to identify those CAIB report elements with NASA-wide applicability and to develop corrective measures to address each element. One such measure was the development of a standard for the development, documentation, and operation of models and simulations. This report describes the philosophy and requirements overview of the resulting NASA Standard for Models and Simulations.

An Agent-Based Monetary Production Simulation Model

DEFF Research Database (Denmark)

Bruun, Charlotte

2006-01-01

An Agent-Based Simulation Model Programmed in Objective Borland Pascal. Program and source code is downloadable......An Agent-Based Simulation Model Programmed in Objective Borland Pascal. Program and source code is downloadable...

Materials for the nuclear - Modelling and simulation of structure materials

International Nuclear Information System (INIS)

Berthoud, Georges; Ducros, Gerard; Feron, Damien; Guerin, Yannick; Latge, Christian; Limoge, Yves; Santarini, Gerard; Seiler, Jean-Marie; Vernaz, Etienne; Cappelaere, Chantal; Andrieux, Catherine; Athenes, Manuel; Baldinozzi, Guido; Bechade, Jean-Luc; Bonin, Bernard; Boutard, Jean-Louis; Brechet, Yves; Bruneval, Fabien; Carassou, Sebastien; Castelier, Etienne; Chartier, Alain; Clouet, Emmanuel; Marinica, Mihai-Cosmin; Crocombette, Jean-Paul; Dupuy, Laurent; Forget, Pierre; Fu, Chu Chun; Garnier, Jerome; Gelebart, Lionel; Henry, Jean; Jourdan, Thomas; Luneville, Laurence; Marini, Bernard; Meslin, Estelle; Nastar, Maylise; Onimus, Fabien; Poussard, Christophe; Proville, Laurent; Ribis, Joel; Robertson, Christian; Rodney, David; Roma, Guido; Sauzay, Maxime; Simeone, David; Soisson, Frederic; Tanguy, Benoit; Toffolon-Masclet, Caroline; Trocellier, Patrick; Van Brutzel, Laurent; Ventelon, Usa; Vincent, Ludovic; Willaime, Francois; Yvon, Pascal; Behar, Christophe; Provitina, Olivier; Lecomte, Michael; Forestier, Alain; Bender, Alexandra; Parisot, Jean-Francois; Finot, Pierre

2016-01-01

This collective publication proposes presentations of scientific approaches implemented to model and simulate the behaviour of materials submitted to irradiation, of associated experimental methods, and of some recent important results. After an introduction presenting the various materials used in different types of nuclear reactors (PWR, etc.), the effects of irradiation at the macroscopic or at the atomic scale, and the multi-scale (time and space) approach to the modelling of these materials, a chapter proposes an overview of modelling tools: multi-scale approach, electronic calculations for condensed matter, inter-atomic potentials, molecular dynamics simulation, thermodynamic and medium force potentials, phase diagrams, simulation of primary damages in reactor materials, kinetic models, dislocation dynamics, production of microstructures for simulation, crystalline visco-plasticity, homogenization methods in continuum mechanics, local approach and probabilistic approach in material fracture. The next part presents tools for experimental validation: tools for microscopic characterization or for mechanical characterization, experimental reactors and tests in atomic pile, tools for irradiation by charged particles. The next chapters presents different examples of thermodynamic and kinetic modelling in the case of various alloys (zirconium alloys, iron-chromium alloys, silicon carbide, austenitic alloys), of plasticity and failure modelling

A Model-Based Framework for Legal Policy Simulation and Compliance Checking

OpenAIRE

Soltana, Ghanem

2017-01-01

Information systems implementing requirements from laws and regulations, such as taxes and social benefits, need to be thoroughly verified to demonstrate their compliance. Several Verification and Validation (V&V) techniques, such as reliability testing, and modeling and simulation, can be used for assessing that such systems meet their legal. Typically, one has to model the expected (legal) behavior of the system in a form that can be executed (simulated), subject the resulting models and th...

Validation of the simulator neutronics model

International Nuclear Information System (INIS)

Gregory, M.V.

1984-01-01

The neutronics model in the SRP reactor training simulator computes the variation with time of the neutron population in the reactor core. The power output of a reactor is directly proportional to the neutron population, thus in a very real sense the neutronics model determines the response of the simulator. The geometrical complexity of the reactor control system in SRP reactors requires the neutronics model to provide a detailed, 3D representation of the reactor core. Existing simulator technology does not allow such a detailed representation to run in real-time in a minicomputer environment, thus an entirely different approach to the problem was required. A prompt jump method has been developed in answer to this need

Photovoltaic array performance simulation models

Energy Technology Data Exchange (ETDEWEB)

Menicucci, D. F.

1986-09-15

The experience of the solar industry confirms that, despite recent cost reductions, the profitability of photovoltaic (PV) systems is often marginal and the configuration and sizing of a system is a critical problem for the design engineer. Construction and evaluation of experimental systems are expensive and seldom justifiable. A mathematical model or computer-simulation program is a desirable alternative, provided reliable results can be obtained. Sandia National Laboratories, Albuquerque (SNLA), has been studying PV-system modeling techniques in an effort to develop an effective tool to be used by engineers and architects in the design of cost-effective PV systems. This paper reviews two of the sources of error found in previous PV modeling programs, presents the remedies developed to correct these errors, and describes a new program that incorporates these improvements.

Simulation and Modeling of Flow in a Gas Compressor

Directory of Open Access Journals (Sweden)

Anna Avramenko

2015-01-01

Full Text Available The presented research demonstrates the results of a series of numerical simulations of gas flow through a single-stage centrifugal compressor with a vaneless diffuser. Numerical results were validated with experiments consisting of eight regimes with different mass flow rates. The steady-state and unsteady simulations were done in ANSYS FLUENT 13.0 and NUMECA FINE/TURBO 8.9.1 for one-period geometry due to periodicity of the problem. First-order discretization is insufficient due to strong dissipation effects. Results obtained with second-order discretization agree with the experiments for the steady-state case in the region of high mass flow rates. In the area of low mass flow rates, nonstationary effects significantly influence the flow leading stationary model to poor prediction. Therefore, the unsteady simulations were performed in the region of low mass flow rates. Results of calculation were compared with experimental data. The numerical simulation method in this paper can be used to predict compressor performance.

Model for Simulation Atmospheric Turbulence

DEFF Research Database (Denmark)

Lundtang Petersen, Erik

1976-01-01

A method that produces realistic simulations of atmospheric turbulence is developed and analyzed. The procedure makes use of a generalized spectral analysis, often called a proper orthogonal decomposition or the Karhunen-Loève expansion. A set of criteria, emphasizing a realistic appearance...... eigenfunctions and estimates of the distributions of the corresponding expansion coefficients. The simulation method utilizes the eigenfunction expansion procedure to produce preliminary time histories of the three velocity components simultaneously. As a final step, a spectral shaping procedure is then applied....... The method is unique in modeling the three velocity components simultaneously, and it is found that important cross-statistical features are reasonably well-behaved. It is concluded that the model provides a practical, operational simulator of atmospheric turbulence....

Modeling and Fault Simulation of Propellant Filling System

International Nuclear Information System (INIS)

Jiang Yunchun; Liu Weidong; Hou Xiaobo

2012-01-01

Propellant filling system is one of the key ground plants in launching site of rocket that use liquid propellant. There is an urgent demand for ensuring and improving its reliability and safety, and there is no doubt that Failure Mode Effect Analysis (FMEA) is a good approach to meet it. Driven by the request to get more fault information for FMEA, and because of the high expense of propellant filling, in this paper, the working process of the propellant filling system in fault condition was studied by simulating based on AMESim. Firstly, based on analyzing its structure and function, the filling system was modular decomposed, and the mathematic models of every module were given, based on which the whole filling system was modeled in AMESim. Secondly, a general method of fault injecting into dynamic system was proposed, and as an example, two typical faults - leakage and blockage - were injected into the model of filling system, based on which one can get two fault models in AMESim. After that, fault simulation was processed and the dynamic characteristics of several key parameters were analyzed under fault conditions. The results show that the model can simulate effectively the two faults, and can be used to provide guidance for the filling system maintain and amelioration.

Agent Based Modelling for Social Simulation

OpenAIRE

Smit, S.K.; Ubink, E.M.; Vecht, B. van der; Langley, D.J.

2013-01-01

This document is the result of an exploratory project looking into the status of, and opportunities for Agent Based Modelling (ABM) at TNO. The project focussed on ABM applications containing social interactions and human factors, which we termed ABM for social simulation (ABM4SS). During the course of this project two workshops were organized. At these workshops, a wide range of experts, both ABM experts and domain experts, worked on several potential applications of ABM. The results and ins...

System modeling and simulation at EBR-II

International Nuclear Information System (INIS)

Dean, E.M.; Lehto, W.K.; Larson, H.A.

1986-01-01

The codes being developed and verified using EBR-II data are the NATDEMO, DSNP and CSYRED. NATDEMO is a variation of the Westinghouse DEMO code coupled to the NATCON code previously used to simulate perturbations of reactor flow and inlet temperature and loss-of-flow transients leading to natural convection in EBR-II. CSYRED uses the Continuous System Modeling Program (CSMP) to simulate the EBR-II core, including power, temperature, control-rod movement reactivity effects and flow and is used primarily to model reactivity induced power transients. The Dynamic Simulator for Nuclear Power Plants (DSNP) allows a whole plant, thermal-hydraulic simulation using specific component and system models called from libraries. It has been used to simulate flow coastdown transients, reactivity insertion events and balance-of-plant perturbations

JPL Thermal Design Modeling Philosophy and NASA-STD-7009 Standard for Models and Simulations - A Case Study

Science.gov (United States)

Avila, Arturo

2011-01-01

The Standard JPL thermal engineering practice prescribes worst-case methodologies for design. In this process, environmental and key uncertain thermal parameters (e.g., thermal blanket performance, interface conductance, optical properties) are stacked in a worst case fashion to yield the most hot- or cold-biased temperature. Thus, these simulations would represent the upper and lower bounds. This, effectively, represents JPL thermal design margin philosophy. Uncertainty in the margins and the absolute temperatures is usually estimated by sensitivity analyses and/or by comparing the worst-case results with "expected" results. Applicability of the analytical model for specific design purposes along with any temperature requirement violations are documented in peer and project design review material. In 2008, NASA released NASA-STD-7009, Standard for Models and Simulations. The scope of this standard covers the development and maintenance of models, the operation of simulations, the analysis of the results, training, recommended practices, the assessment of the Modeling and Simulation (M&S) credibility, and the reporting of the M&S results. The Mars Exploration Rover (MER) project thermal control system M&S activity was chosen as a case study determining whether JPL practice is in line with the standard and to identify areas of non-compliance. This paper summarizes the results and makes recommendations regarding the application of this standard to JPL thermal M&S practices.

SiO2-Ta2O5 sputtering yields: simulated and experimental results

International Nuclear Information System (INIS)

Vireton, E.; Ganau, P.; Mackowski, J.M.; Michel, C.; Pinard, L.; Remillieux, A.

1994-09-01

To improve mirrors coating, we have modeled sputtering of binary oxide targets using TRIM code. First, we have proposed a method to calculate TRIM input parameters using on the one hand thermodynamic cycle and on the other hand Malherbe's results. Secondly, an iterative processing has provided for oxide steady targets caused by ionic bombardment. Thirdly, we have exposed a model to get experimental sputtering yields. Fourthly, for (Ar - SiO 2 ) pair, we have determined that steady target is a silica one. A good agreement between simulated and experimental yields versus ion incident angle has been found. For (Ar - Ta 2 O 5 ) pair, we have to introduce preferential sputtering concept to explain discrepancy between simulation and experiment. In this case, steady target is tantalum monoxide. For (Ar - Ta(+O 2 ) pair, tantalum sputtered by argon ions in reactive oxygen atmosphere, we have to take into account new concept of oxidation stimulated by ion beam. We have supposed that tantalum target becomes a Ta 2 O 5 one in reactive oxygen atmosphere. Then, following mechanism is similar to previous pair. We have obtained steady target of tantalum monoxide too. Comparison between simulated and experimental sputtering yields versus ion incident angle has given very good agreement. By simulation, we have found that tantalum monoxide target has at least 15 angstrom thickness. Those results are compatible with Malherbe's and Taglauer's ones. (authors)

COMPUTER MODEL AND SIMULATION OF A GLOVE BOX PROCESS

International Nuclear Information System (INIS)

Foster, C.

2001-01-01

The development of facilities to deal with the disposition of nuclear materials at an acceptable level of Occupational Radiation Exposure (ORE) is a significant issue facing the nuclear community. One solution is to minimize the worker's exposure though the use of automated systems. However, the adoption of automated systems for these tasks is hampered by the challenging requirements that these systems must meet in order to be cost effective solutions in the hazardous nuclear materials processing environment. Retrofitting current glove box technologies with automation systems represents potential near-term technology that can be applied to reduce worker ORE associated with work in nuclear materials processing facilities. Successful deployment of automation systems for these applications requires the development of testing and deployment strategies to ensure the highest level of safety and effectiveness. Historically, safety tests are conducted with glove box mock-ups around the finished design. This late detection of problems leads to expensive redesigns and costly deployment delays. With wide spread availability of computers and cost effective simulation software it is possible to discover and fix problems early in the design stages. Computer simulators can easily create a complete model of the system allowing a safe medium for testing potential failures and design shortcomings. The majority of design specification is now done on computer and moving that information to a model is relatively straightforward. With a complete model and results from a Failure Mode Effect Analysis (FMEA), redesigns can be worked early. Additional issues such as user accessibility, component replacement, and alignment problems can be tackled early in the virtual environment provided by computer simulation. In this case, a commercial simulation package is used to simulate a lathe process operation at the Los Alamos National Laboratory (LANL). The Lathe process operation is indicative of

Lattice simulation of 2d Gross-Neveu-type models

International Nuclear Information System (INIS)

Limmer, M.; Gattringer, C.; Hermann, V.

2006-01-01

Full text: We discuss a Monte Carlo simulation of 2d Gross-Neveu-type models on the lattice. The four-Fermi interaction is written as a Gaussian integral with an auxiliary field and the fermion determinant is included by reweighting. We present results for bulk quantities and correlators and compare them to a simulation using a fermion-loop representation. (author)

Modelling and Manufacturing of a 3D Printed Trachea for Cricothyroidotomy Simulation.

Science.gov (United States)

Doucet, Gregory; Ryan, Stephen; Bartellas, Michael; Parsons, Michael; Dubrowski, Adam; Renouf, Tia

2017-08-18

Cricothyroidotomy is a life-saving medical procedure that allows for tracheal intubation. Most current cricothyroidotomy simulation models are either expensive or not anatomically accurate and provide the learner with an unrealistic simulation experience. The goal of this project is to improve current simulation techniques by utilizing rapid prototyping using 3D printing technology and expert opinions to develop inexpensive and anatomically accurate trachea simulators. In doing so, emergency cricothyroidotomy simulation can be made accessible, accurate, cost-effective and reproducible. Three-dimensional modelling software was used in conjunction with a desktop three-dimensional (3D) printer to design and manufacture an anatomically accurate model of the cartilage within the trachea (thyroid cartilage, cricoid cartilage, and the tracheal rings). The initial design was based on dimensions found in studies of tracheal anatomical configuration. This ensured that the landmarking necessary for emergency cricothyroidotomies was designed appropriately. Several revisions of the original model were made based on informal opinion from medical professionals to establish appropriate anatomical accuracy of the model for use in rural/remote cricothyroidotomy simulation. Using an entry-level desktop 3D printer, a low cost tracheal model was successfully designed that can be printed in less than three hours for only $1.70 Canadian dollars (CAD). Due to its anatomical accuracy, flexibility and durability, this model is great for use in emergency medicine simulation training. Additionally, the model can be assembled in conjunction with a membrane to simulate tracheal ligaments. Skin has been simulated as well to enhance the realism of the model. The result is an accurate simulation that will provide users with an anatomically correct model to practice important skills used in emergency airway surgery, specifically landmarking, incision and intubation. This design is a novel and easy

Modelling interplanetary CMEs using magnetohydrodynamic simulations

Directory of Open Access Journals (Sweden)

P. J. Cargill

Full Text Available The dynamics of Interplanetary Coronal Mass Ejections (ICMEs are discussed from the viewpoint of numerical modelling. Hydrodynamic models are shown to give a good zero-order picture of the plasma properties of ICMEs, but they cannot model the important magnetic field effects. Results from MHD simulations are shown for a number of cases of interest. It is demonstrated that the strong interaction of the ICME with the solar wind leads to the ICME and solar wind velocities being close to each other at 1 AU, despite their having very different speeds near the Sun. It is also pointed out that this interaction leads to a distortion of the ICME geometry, making cylindrical symmetry a dubious assumption for the CME field at 1 AU. In the presence of a significant solar wind magnetic field, the magnetic fields of the ICME and solar wind can reconnect with each other, leading to an ICME that has solar wind-like field lines. This effect is especially important when an ICME with the right sense of rotation propagates down the heliospheric current sheet. It is also noted that a lack of knowledge of the coronal magnetic field makes such simulations of little use in space weather forecasts that require knowledge of the ICME magnetic field strength.

Key words. Interplanetary physics (interplanetary magnetic fields Solar physics, astrophysics, and astronomy (flares and mass ejections Space plasma physics (numerical simulation studies

Comparing Numerical Spall Simulations with a Nonlinear Spall Formation Model

Science.gov (United States)

Ong, L.; Melosh, H. J.

2012-12-01

Spallation accelerates lightly shocked ejecta fragments to speeds that can exceed the escape velocity of the parent body. We present high-resolution simulations of nonlinear shock interactions in the near surface. Initial results show the acceleration of near-surface material to velocities up to 1.8 times greater than the peak particle velocity in the detached shock, while experiencing little to no shock pressure. These simulations suggest a possible nonlinear spallation mechanism to produce the high-velocity, low show pressure meteorites from other planets. Here we pre-sent the numerical simulations that test the production of spall through nonlinear shock interactions in the near sur-face, and compare the results with a model proposed by Kamegai (1986 Lawrence Livermore National Laboratory Report). We simulate near-surface shock interactions using the SALES_2 hydrocode and the Murnaghan equation of state. We model the shock interactions in two geometries: rectangular and spherical. In the rectangular case, we model a planar shock approaching the surface at a constant angle phi. In the spherical case, the shock originates at a point below the surface of the domain and radiates spherically from that point. The angle of the shock front with the surface is dependent on the radial distance of the surface point from the shock origin. We model the target as a solid with a nonlinear Murnaghan equation of state. This idealized equation of state supports nonlinear shocks but is tem-perature independent. We track the maximum pressure and maximum velocity attained in every cell in our simula-tions and compare them to the Hugoniot equations that describe the material conditions in front of and behind the shock. Our simulations demonstrate that nonlinear shock interactions in the near surface produce lightly shocked high-velocity material for both planar and cylindrical shocks. The spall is the result of the free surface boundary condi-tion, which forces a pressure gradient

Simulation modeling for the health care manager.

Science.gov (United States)

Kennedy, Michael H

2009-01-01

This article addresses the use of simulation software to solve administrative problems faced by health care managers. Spreadsheet add-ins, process simulation software, and discrete event simulation software are available at a range of costs and complexity. All use the Monte Carlo method to realistically integrate probability distributions into models of the health care environment. Problems typically addressed by health care simulation modeling are facility planning, resource allocation, staffing, patient flow and wait time, routing and transportation, supply chain management, and process improvement.

A Probabilistic Model of Meter Perception: Simulating Enculturation

Directory of Open Access Journals (Sweden)

Bastiaan van der Weij

2017-05-01

Full Text Available Enculturation is known to shape the perception of meter in music but this is not explicitly accounted for by current cognitive models of meter perception. We hypothesize that the induction of meter is a result of predictive coding: interpreting onsets in a rhythm relative to a periodic meter facilitates prediction of future onsets. Such prediction, we hypothesize, is based on previous exposure to rhythms. As such, predictive coding provides a possible explanation for the way meter perception is shaped by the cultural environment. Based on this hypothesis, we present a probabilistic model of meter perception that uses statistical properties of the relation between rhythm and meter to infer meter from quantized rhythms. We show that our model can successfully predict annotated time signatures from quantized rhythmic patterns derived from folk melodies. Furthermore, we show that by inferring meter, our model improves prediction of the onsets of future events compared to a similar probabilistic model that does not infer meter. Finally, as a proof of concept, we demonstrate how our model can be used in a simulation of enculturation. From the results of this simulation, we derive a class of rhythms that are likely to be interpreted differently by enculturated listeners with different histories of exposure to rhythms.

Advancing Material Models for Automotive Forming Simulations

International Nuclear Information System (INIS)

Vegter, H.; An, Y.; Horn, C.H.L.J. ten; Atzema, E.H.; Roelofsen, M.E.

2005-01-01

Simulations in automotive industry need more advanced material models to achieve highly reliable forming and springback predictions. Conventional material models implemented in the FEM-simulation models are not capable to describe the plastic material behaviour during monotonic strain paths with sufficient accuracy. Recently, ESI and Corus co-operate on the implementation of an advanced material model in the FEM-code PAMSTAMP 2G. This applies to the strain hardening model, the influence of strain rate, and the description of the yield locus in these models. A subsequent challenge is the description of the material after a change of strain path.The use of advanced high strength steels in the automotive industry requires a description of plastic material behaviour of multiphase steels. The simplest variant is dual phase steel consisting of a ferritic and a martensitic phase. Multiphase materials also contain a bainitic phase in addition to the ferritic and martensitic phase. More physical descriptions of strain hardening than simple fitted Ludwik/Nadai curves are necessary.Methods to predict plastic behaviour of single-phase materials use a simple dislocation interaction model based on the formed cells structures only. At Corus, a new method is proposed to predict plastic behaviour of multiphase materials have to take hard phases into account, which deform less easily. The resulting deformation gradients create geometrically necessary dislocations. Additional micro-structural information such as morphology and size of hard phase particles or grains is necessary to derive the strain hardening models for this type of materials.Measurements available from the Numisheet benchmarks allow these models to be validated. At Corus, additional measured values are available from cross-die tests. This laboratory test can attain critical deformations by large variations in blank size and processing conditions. The tests are a powerful tool in optimising forming simulations prior

Guidelines for Reproducibly Building and Simulating Systems Biology Models.

Science.gov (United States)

Medley, J Kyle; Goldberg, Arthur P; Karr, Jonathan R

2016-10-01

Reproducibility is the cornerstone of the scientific method. However, currently, many systems biology models cannot easily be reproduced. This paper presents methods that address this problem. We analyzed the recent Mycoplasma genitalium whole-cell (WC) model to determine the requirements for reproducible modeling. We determined that reproducible modeling requires both repeatable model building and repeatable simulation. New standards and simulation software tools are needed to enhance and verify the reproducibility of modeling. New standards are needed to explicitly document every data source and assumption, and new deterministic parallel simulation tools are needed to quickly simulate large, complex models. We anticipate that these new standards and software will enable researchers to reproducibly build and simulate more complex models, including WC models.

Electromagnetic simulations of simple models of ferrite loaded kickers

CERN Document Server

Zannini, Carlo; Salvant, B; Metral, E; Rumolo, G

2010-01-01

The kickers are major contributors to the CERN SPS beam coupling impedance. As such, they may represent a limitation to increasing the SPS bunch current in the frame of an intensity upgrade of the LHC. In this paper, CST Particle Studio time domain electromagnetic simulations are performed to obtain the longitudinal and transverse impedances/wake potentials of simplified models of ferrite loaded kickers. The simulation results have been successfully compared with some existing analytical expressions. In the transverse plane, the dipolar and quadrupolar contributions to the wake potentials have been estimated from the results of these simulations. For some cases, simulations have also been benchmarked against measurements on PS kickers. It turns out that the large simulated quadrupolar contributions of these kickers could explain both the negative total (dipolar+quadrupolar) horizontal impedance observed in bench measurements and the positive horizontal tune shift measured with the SPS beam.

Dynamics Modeling and Simulation of Large Transport Airplanes in Upset Conditions

Science.gov (United States)

Foster, John V.; Cunningham, Kevin; Fremaux, Charles M.; Shah, Gautam H.; Stewart, Eric C.; Rivers, Robert A.; Wilborn, James E.; Gato, William

2005-01-01

As part of NASA's Aviation Safety and Security Program, research has been in progress to develop aerodynamic modeling methods for simulations that accurately predict the flight dynamics characteristics of large transport airplanes in upset conditions. The motivation for this research stems from the recognition that simulation is a vital tool for addressing loss-of-control accidents, including applications to pilot training, accident reconstruction, and advanced control system analysis. The ultimate goal of this effort is to contribute to the reduction of the fatal accident rate due to loss-of-control. Research activities have involved accident analyses, wind tunnel testing, and piloted simulation. Results have shown that significant improvements in simulation fidelity for upset conditions, compared to current training simulations, can be achieved using state-of-the-art wind tunnel testing and aerodynamic modeling methods. This paper provides a summary of research completed to date and includes discussion on key technical results, lessons learned, and future research needs.

A virtual source model for Monte Carlo simulation of helical tomotherapy.

Science.gov (United States)

Yuan, Jiankui; Rong, Yi; Chen, Quan

2015-01-08

The purpose of this study was to present a Monte Carlo (MC) simulation method based on a virtual source, jaw, and MLC model to calculate dose in patient for helical tomotherapy without the need of calculating phase-space files (PSFs). Current studies on the tomotherapy MC simulation adopt a full MC model, which includes extensive modeling of radiation source, primary and secondary jaws, and multileaf collimator (MLC). In the full MC model, PSFs need to be created at different scoring planes to facilitate the patient dose calculations. In the present work, the virtual source model (VSM) we established was based on the gold standard beam data of a tomotherapy unit, which can be exported from the treatment planning station (TPS). The TPS-generated sinograms were extracted from the archived patient XML (eXtensible Markup Language) files. The fluence map for the MC sampling was created by incorporating the percentage leaf open time (LOT) with leaf filter, jaw penumbra, and leaf latency contained from sinogram files. The VSM was validated for various geometry setups and clinical situations involving heterogeneous media and delivery quality assurance (DQA) cases. An agreement of < 1% was obtained between the measured and simulated results for percent depth doses (PDDs) and open beam profiles for all three jaw settings in the VSM commissioning. The accuracy of the VSM leaf filter model was verified in comparing the measured and simulated results for a Picket Fence pattern. An agreement of < 2% was achieved between the presented VSM and a published full MC model for heterogeneous phantoms. For complex clinical head and neck (HN) cases, the VSM-based MC simulation of DQA plans agreed with the film measurement with 98% of planar dose pixels passing on the 2%/2 mm gamma criteria. For patient treatment plans, results showed comparable dose-volume histograms (DVHs) for planning target volumes (PTVs) and organs at risk (OARs). Deviations observed in this study were consistent

Mathematical modelling of plant transients in the PWR for simulator purposes

International Nuclear Information System (INIS)

Hartel, K.

1984-01-01

This chapter presents the results of the testing of anticipated and abnormal plant transients in pressurized water reactors (PWRs) of the type WWER 440 by means of the numerical simulation of 32 different, stationary and nonstationary, operational regimes. Topics considered include the formation of the PWR mathematical model, the physical approximation of the reactor core, the structure of the reactor core model, a mathematical approximation of the reactor model, the selection of numerical methods, and a computerized simulation system. The necessity of a PWR simulator in Czechoslovakia is justified by the present status and the outlook for the further development of the Czechoslovak nuclear power complex

Geologic simulation model for a hypothetical site in the Columbia Plateau

International Nuclear Information System (INIS)

Petrie, G.M.; Zellmer, J.T.; Lindberg, J.W.; Foley, M.G.

1981-04-01

This report describes the structure and operation of the Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) Geologic Simulation Model, a computer simulation model of the geology and hydrology of an area of the Columbia Plateau, Washington. The model is used to study the long-term suitability of the Columbia Plateau Basalts for the storage of nuclear waste in a mined repository. It is also a starting point for analyses of such repositories in other geologic settings. The Geologic Simulation Model will aid in formulating design disruptive sequences (i.e. those to be used for more detailed hydrologic, transport, and dose analyses) from the spectrum of hypothetical geological and hydrological developments that could result in transport of radionuclides out of a repository. Quantitative and auditable execution of this task, however, is impossible without computer simulation. The computer simulation model aids the geoscientist by generating the wide spectrum of possible future evolutionary paths of the areal geology and hydrology, identifying those that may affect the repository integrity. This allows the geoscientist to focus on potentially disruptive processes, or series of events. Eleven separate submodels are used in the simulation portion of the model: Climate, Continental Glaciation, Deformation, Geomorphic Events, Hydrology, Magmatic Events, Meteorite Impact, Sea-Level Fluctuations, Shaft-Seal Failure, Sub-Basalt Basement Faulting, and Undetected Features. Because of the modular construction of the model, each submodel can easily be replaced with an updated or modified version as new information or developments in the state of the art become available. The model simulates the geologic and hydrologic systems of a hypothetical repository site and region for a million years following repository decommissioning. The Geologic Simulation Model operates in both single-run and Monte Carlo modes

Visualizing Flutter Mechanism as Traveling Wave Through Animation of Simulation Results for the Semi-Span Super-Sonic Transport Wind-Tunnel Model

Science.gov (United States)

Christhilf, David M.

2014-01-01

It has long been recognized that frequency and phasing of structural modes in the presence of airflow play a fundamental role in the occurrence of flutter. Animation of simulation results for the long, slender Semi-Span Super-Sonic Transport (S4T) wind-tunnel model demonstrates that, for the case of mass-ballasted nacelles, the flutter mode can be described as a traveling wave propagating downstream. Such a characterization provides certain insights, such as (1) describing the means by which energy is transferred from the airflow to the structure, (2) identifying airspeed as an upper limit for speed of wave propagation, (3) providing an interpretation for a companion mode that coalesces in frequency with the flutter mode but becomes very well damped, (4) providing an explanation for bursts of response to uniform turbulence, and (5) providing an explanation for loss of low frequency (lead) phase margin with increases in dynamic pressure (at constant Mach number) for feedback systems that use sensors located upstream from active control surfaces. Results from simulation animation, simplified modeling, and wind-tunnel testing are presented for comparison. The simulation animation was generated using double time-integration in Simulink of vertical accelerometer signals distributed over wing and fuselage, along with time histories for actuated control surfaces. Crossing points for a zero-elevation reference plane were tracked along a network of lines connecting the accelerometer locations. Accelerometer signals were used in preference to modal displacement state variables in anticipation that the technique could be used to animate motion of the actual wind-tunnel model using data acquired during testing. Double integration of wind-tunnel accelerometer signals introduced severe drift even with removal of both position and rate biases such that the technique does not currently work. Using wind-tunnel data to drive a Kalman filter based upon fitting coefficients to

Dynamic wind turbine models in power system simulation tool DIgSILENT

OpenAIRE

Hansen, A.D.; Jauch, C.; Sørensen, Poul Ejnar; Iov, F.; Blaabjerg, F.

2004-01-01

The present report describes the dynamic wind turbine models implemented in the power system simulation tool DIgSILENT (Version 12.0). The developed models are a part of the results of a national research project, whose overall objective is to create amodel database in different simulation tools. This model database should be able to support the analysis of the interaction between the mechanical structure of the wind turbine and the electrical grid during different operational modes. The repo...

Evaluation of sub grid scale and local wall models in Large-eddy simulations of separated flow

Directory of Open Access Journals (Sweden)

Sam Ali Al

2015-01-01

Full Text Available The performance of the Sub Grid Scale models is studied by simulating a separated flow over a wavy channel. The first and second order statistical moments of the resolved velocities obtained by using Large-Eddy simulations at different mesh resolutions are compared with Direct Numerical Simulations data. The effectiveness of modeling the wall stresses by using local log-law is then tested on a relatively coarse grid. The results exhibit a good agreement between highly-resolved Large Eddy Simulations and Direct Numerical Simulations data regardless the Sub Grid Scale models. However, the agreement is less satisfactory with relatively coarse grid without using any wall models and the differences between Sub Grid Scale models are distinguishable. Using local wall model retuned the basic flow topology and reduced significantly the differences between the coarse meshed Large-Eddy Simulations and Direct Numerical Simulations data. The results show that the ability of local wall model to predict the separation zone depends strongly on its implementation way.