WorldWideScience

Sample records for benchmark simulation model

  1. Benchmark simulation models, quo vadis?

    DEFF Research Database (Denmark)

    Jeppsson, U.; Alex, J; Batstone, D. J.;

    2013-01-01

    and spatial extension, process modifications within the WWTP, the realism of models, control strategy extensions and the potential for new evaluation tools within the existing benchmark system. We find that there are major opportunities for application within all of these areas, either from existing work...... already being done within the context of the benchmarking simulation models (BSMs) or applicable work in the wider literature. Of key importance is increasing capability, usability and transparency of the BSM package while avoiding unnecessary complexity. © IWA Publishing 2013....

  2. Benchmark simulation models, quo vadis?

    Science.gov (United States)

    Jeppsson, U; Alex, J; Batstone, D J; Benedetti, L; Comas, J; Copp, J B; Corominas, L; Flores-Alsina, X; Gernaey, K V; Nopens, I; Pons, M-N; Rodríguez-Roda, I; Rosen, C; Steyer, J-P; Vanrolleghem, P A; Volcke, E I P; Vrecko, D

    2013-01-01

    As the work of the IWA Task Group on Benchmarking of Control Strategies for wastewater treatment plants (WWTPs) is coming to an end, it is essential to disseminate the knowledge gained. For this reason, all authors of the IWA Scientific and Technical Report on benchmarking have come together to provide their insights, highlighting areas where knowledge may still be deficient and where new opportunities are emerging, and to propose potential avenues for future development and application of the general benchmarking framework and its associated tools. The paper focuses on the topics of temporal and spatial extension, process modifications within the WWTP, the realism of models, control strategy extensions and the potential for new evaluation tools within the existing benchmark system. We find that there are major opportunities for application within all of these areas, either from existing work already being done within the context of the benchmarking simulation models (BSMs) or applicable work in the wider literature. Of key importance is increasing capability, usability and transparency of the BSM package while avoiding unnecessary complexity.

  3. Benchmark Simulation Model No 2 in Matlab-Simulink

    DEFF Research Database (Denmark)

    Vrecko, Darko; Gernaey, Krist; Rosen, Christian

    2006-01-01

    In this paper, implementation of the Benchmark Simulation Model No 2 (BSM2) within Matlab-Simulink is presented. The BSM2 is developed for plant-wide WWTP control strategy evaluation on a long-term basis. It consists of a pre-treatment process, an activated sludge process and sludge treatment...

  4. Benchmark Simulation Model No 2 – finalisation of plant layout and default control strategy

    DEFF Research Database (Denmark)

    Nopens, I.; Benedetti, L.; Jeppsson, U.;

    2010-01-01

    The COST/IWA Benchmark Simulation Model No 1 (BSM1) has been available for almost a decade. Its primary purpose has been to create a platform for control strategy benchmarking of activated sludge processes. The fact that the research work related to the benchmark simulation models has resulted...... in more than 300 publications worldwide demonstrates the interest in and need of such tools within the research community. Recent efforts within the IWA Task Group on “Benchmarking of control strategies for WWTPs” have focused on an extension of the benchmark simulation model. This extension aims...... at facilitating control strategy development and performance evaluation at a plant-wide level and, consequently, includes both pretreatment of wastewater as well as the processes describing sludge treatment. The motivation for the extension is the increasing interest and need to operate and control wastewater...

  5. Benchmark simulation model no 2: general protocol and exploratory case studies

    DEFF Research Database (Denmark)

    Jeppsson, U.; Pons, M.N.; Nopens, I.

    2007-01-01

    Over a decade ago, the concept of objectively evaluating the performance of control strategies by simulating them using a standard model implementation was introduced for activated sludge wastewater treatment plants. The resulting Benchmark Simulation Model No 1 (BSM1) has been the basis for a si...

  6. Towards a benchmark simulation model for plant-wide control strategy performance evaluation of WWTPs

    DEFF Research Database (Denmark)

    Jeppsson, Ulf; Rosen, Christian; Alex, Jens;

    2006-01-01

    The COST/IWA benchmark simulation model has been available for seven years. Its primary purpose has been to create a platform for control strategy benchmarking of activated sludge processes. The fact that the benchmark has resulted in more than 100 publications, not only in Europe but also...... worldwide, demonstrates the interest in such a tool within the research community In this paper, an extension of the benchmark simulation model no 1 (BSM1) is proposed. This extension aims at facilitating control strategy development and performance evaluation at a plant-wide level and, consequently...... the changes, the evaluation period has been extended to one year. A prolonged evaluation period allows for long-term control strategies to be assessed and enables the use of control handles that cannot be evaluated in a realistic fashion in the one-week BSM1 evaluation period. In the paper, the extended plant...

  7. Uncertainty and sensitivity analysis of control strategies using the benchmark simulation model No1 (BSM1)

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Rodriguez-Roda, Ignasi; Sin, Gürkan

    2009-01-01

    The objective of this paper is to perform an uncertainty and sensitivity analysis of the predictions of the Benchmark Simulation Model (BSM) No. 1, when comparing four activated sludge control strategies. The Monte Carlo simulation technique is used to evaluate the uncertainty in the BSM1 predict...

  8. Catchment & sewer network simulation model to benchmark control strategies within urban wastewater systems

    DEFF Research Database (Denmark)

    Saagi, Ramesh; Flores Alsina, Xavier; Fu, Guangtao

    2016-01-01

    This paper aims at developing a benchmark simulation model to evaluate control strategies for the urban catchment and sewer network. Various modules describing wastewater generation in the catchment, its subsequent transport and storage in the sewer system are presented. Global/local overflow bas...

  9. A benchmark simulation model to describe plant-wide phosphorus transformations in WWTPs

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Ikumi, D.; Kazadi-Mbamba, C.

    It is more than 10 years since the publication of the BSM1 technical report (Copp, 2002). The main objective of BSM1 was to create a platform for benchmarking C and N removal strategies in activated sludge systems. The initial platform evolved into BSM1_LT and BSM2, which allowed for the evaluati...... to be addressed and presents the simulation results of the first software prototype....... of monitoring and plant-wide control strategies, respectively. In addition, researchers working within the IWA Task Group on Benchmarking of Control Strategies for Wastewater Treatment Plants developed other BSM related spin-off products, such as the dynamic influent generator, sensor/actuators/fault models......) pursue biological/chemical phosphorus removal. However, realistic descriptions of combined C, N and P removal, adds a major, but unavoidable degree of complexity in wastewater treatment process models. This paper identifies and discusses important issues that need to be addressed to upgrade the BSM2...

  10. Benchmarking Computational Fluid Dynamics Models for Application to Lava Flow Simulations and Hazard Assessment

    Science.gov (United States)

    Dietterich, H. R.; Lev, E.; Chen, J.; Cashman, K. V.; Honor, C.

    2015-12-01

    Recent eruptions in Hawai'i, Iceland, and Cape Verde highlight the need for improved lava flow models for forecasting and hazard assessment. Existing models used for lava flow simulation range in assumptions, complexity, and the degree to which they have been validated against analytical solutions, experiments, and natural observations. In order to assess the capabilities of existing models and test the development of new codes, we conduct a benchmarking study of computational fluid dynamics models for lava flows, including VolcFlow, OpenFOAM, Flow3D, and COMSOL. Using new benchmark scenarios defined in Cordonnier et al. (2015) as a guide, we model Newtonian, Herschel-Bulkley and cooling flows over inclined planes, obstacles, and digital elevation models with a wide range of source conditions. Results are compared to analytical theory, analogue and molten basalt experiments, and measurements from natural lava flows. Our study highlights the strengths and weakness of each code, including accuracy and computational costs, and provides insights regarding code selection. We apply the best-fit codes to simulate the lava flows in Harrat Rahat, a predominately mafic volcanic field in Saudi Arabia. Input parameters are assembled from rheology and volume measurements of past flows using geochemistry, crystallinity, and present-day lidar and photogrammetric digital elevation models. With these data, we use our verified models to reconstruct historic and prehistoric events, in order to assess the hazards posed by lava flows for Harrat Rahat.

  11. Linear Active Disturbance Rejection Control of Dissolved Oxygen Concentration Based on Benchmark Simulation Model Number 1

    Directory of Open Access Journals (Sweden)

    Xiaoyi Wang

    2015-01-01

    Full Text Available In wastewater treatment plants (WWTPs, the dissolved oxygen is the key variable to be controlled in bioreactors. In this paper, linear active disturbance rejection control (LADRC is utilized to track the dissolved oxygen concentration based on benchmark simulation model number 1 (BSM1. Optimal LADRC parameters tuning approach for wastewater treatment processes is obtained by analyzing and simulations on BSM1. Moreover, by analyzing the estimation capacity of linear extended state observer (LESO in the control of dissolved oxygen, the parameter range of LESO is acquired, which is a valuable guidance for parameter tuning in simulation and even in practice. The simulation results show that LADRC can overcome the disturbance existing in the control of wastewater and improve the tracking accuracy of dissolved oxygen. LADRC provides another practical solution to the control of WWTPs.

  12. Benchmark of the local drift-kinetic models for neoclassical transport simulation in helical plasmas

    Science.gov (United States)

    Huang, B.; Satake, S.; Kanno, R.; Sugama, H.; Matsuoka, S.

    2017-02-01

    The benchmarks of the neoclassical transport codes based on the several local drift-kinetic models are reported here. Here, the drift-kinetic models are zero orbit width (ZOW), zero magnetic drift, DKES-like, and global, as classified in Matsuoka et al. [Phys. Plasmas 22, 072511 (2015)]. The magnetic geometries of Helically Symmetric Experiment, Large Helical Device (LHD), and Wendelstein 7-X are employed in the benchmarks. It is found that the assumption of E ×B incompressibility causes discrepancy of neoclassical radial flux and parallel flow among the models when E ×B is sufficiently large compared to the magnetic drift velocities. For example, Mp≤0.4 where Mp is the poloidal Mach number. On the other hand, when E ×B and the magnetic drift velocities are comparable, the tangential magnetic drift, which is included in both the global and ZOW models, fills the role of suppressing unphysical peaking of neoclassical radial-fluxes found in the other local models at Er≃0 . In low collisionality plasmas, in particular, the tangential drift effect works well to suppress such unphysical behavior of the radial transport caused in the simulations. It is demonstrated that the ZOW model has the advantage of mitigating the unphysical behavior in the several magnetic geometries, and that it also implements the evaluation of bootstrap current in LHD with the low computation cost compared to the global model.

  13. System-wide Benchmark Simulation Model for integrated analysis of urban wastewater systems

    DEFF Research Database (Denmark)

    Saagi, R.; Flores-Alsina, X.; Gernaey, K. V.

    (Gernaey et al., 2014). Given the success of BSMs in evaluation of control strategies for WWTPs, it is envisioned to spatially expand the plant-wide BSM to a system-wide tool. A system-wide BSM can then play an important role, not only in the evaluation of integrated control strategies, but also...... in developing a better understanding of the interactions between different components of an UWS. This paper aims at presenting a system-wide benchmark simulation model that includes catchment, sewer network, WWTP and receiving water subsystems. A hypothetical UWS layout is defined and an integrated model......Interactions between different components (sewer, wastewater treatment plant (WWTP) and river) of an urban wastewater system (UWS) are widely recognized (Benedetti et al., 2013). This has resulted in an increasing interest in the modelling of the UWS. System-wide models take into account...

  14. Benchmarking Model Variants in Development of a Hardware-in-the-Loop Simulation System

    Science.gov (United States)

    Aretskin-Hariton, Eliot D.; Zinnecker, Alicia M.; Kratz, Jonathan L.; Culley, Dennis E.; Thomas, George L.

    2016-01-01

    Distributed engine control architecture presents a significant increase in complexity over traditional implementations when viewed from the perspective of system simulation and hardware design and test. Even if the overall function of the control scheme remains the same, the hardware implementation can have a significant effect on the overall system performance due to differences in the creation and flow of data between control elements. A Hardware-in-the-Loop (HIL) simulation system is under development at NASA Glenn Research Center that enables the exploration of these hardware dependent issues. The system is based on, but not limited to, the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k). This paper describes the step-by-step conversion from the self-contained baseline model to the hardware in the loop model, and the validation of each step. As the control model hardware fidelity was improved during HIL system development, benchmarking simulations were performed to verify that engine system performance characteristics remained the same. The results demonstrate the goal of the effort; the new HIL configurations have similar functionality and performance compared to the baseline C-MAPSS40k system.

  15. Benchmarking ICRF simulations for ITER

    Energy Technology Data Exchange (ETDEWEB)

    R. V. Budny, L. Berry, R. Bilato, P. Bonoli, M. Brambilla, R.J. Dumont, A. Fukuyama, R. Harvey, E.F. Jaeger, E. Lerche, C.K. Phillips, V. Vdovin, J. Wright, and members of the ITPA-IOS

    2010-09-28

    Abstract Benchmarking of full-wave solvers for ICRF simulations is performed using plasma profiles and equilibria obtained from integrated self-consistent modeling predictions of four ITER plasmas. One is for a high performance baseline (5.3 T, 15 MA) DT H-mode plasma. The others are for half-field, half-current plasmas of interest for the pre-activation phase with bulk plasma ion species being either hydrogen or He4. The predicted profiles are used by seven groups to predict the ICRF electromagnetic fields and heating profiles. Approximate agreement is achieved for the predicted heating power partitions for the DT and He4 cases. Profiles of the heating powers and electromagnetic fields are compared.

  16. Benchmark Generation and Simulation at Extreme Scale

    Energy Technology Data Exchange (ETDEWEB)

    Lagadapati, Mahesh [North Carolina State University (NCSU), Raleigh; Mueller, Frank [North Carolina State University (NCSU), Raleigh; Engelmann, Christian [ORNL

    2016-01-01

    The path to extreme scale high-performance computing (HPC) poses several challenges related to power, performance, resilience, productivity, programmability, data movement, and data management. Investigating the performance of parallel applications at scale on future architectures and the performance impact of different architectural choices is an important component of HPC hardware/software co-design. Simulations using models of future HPC systems and communication traces from applications running on existing HPC systems can offer an insight into the performance of future architectures. This work targets technology developed for scalable application tracing of communication events. It focuses on extreme-scale simulation of HPC applications and their communication behavior via lightweight parallel discrete event simulation for performance estimation and evaluation. Instead of simply replaying a trace within a simulator, this work promotes the generation of a benchmark from traces. This benchmark is subsequently exposed to simulation using models to reflect the performance characteristics of future-generation HPC systems. This technique provides a number of benefits, such as eliminating the data intensive trace replay and enabling simulations at different scales. The presented work features novel software co-design aspects, combining the ScalaTrace tool to generate scalable trace files, the ScalaBenchGen tool to generate the benchmark, and the xSim tool to assess the benchmark characteristics within a simulator.

  17. Benchmark of the Local Drift-kinetic Models for Neoclassical Transport Simulation in Helical Plasmas

    CERN Document Server

    Huang, B; Kanno, R; Sugama, H; Matsuoka, S

    2016-01-01

    The benchmarks of the neoclassical transport codes based on the several local drift-kinetic models are reported here. Here, the drift-kinetic models are ZOW, ZMD, DKES-like, and global, as classified in [Matsuoka et al., Physics of Plasmas 22, 072511 (2015)]. The magnetic geometries of HSX, LHD, and W7-X are employed in the benchmarks. It is found that the assumption of $\\boldsymbol E \\times \\boldsymbol B$ incompressibility causes discrepancy of neoclassical radial flux and parallel flow among the models, when $\\boldsymbol E \\times \\boldsymbol B$ is sufficiently large compared to the magnetic drift velocities. On the other hand, when $\\boldsymbol E \\times \\boldsymbol B$ and the magnetic drift velocities are comparable, the tangential magnetic drift, which is included in both the global and ZOW models, fills the role of suppressing unphysical peaking of neoclassical radial-fluxes found in the other local models at $E_r \\simeq 0$. In low collisionality plasmas, in particular, the tangential drift effect works w...

  18. Simulation Methods for High-Cycle Fatigue-Driven Delamination using Cohesive Zone Models - Fundamental Behavior and Benchmark Studies

    DEFF Research Database (Denmark)

    Bak, Brian Lau Verndal; Lindgaard, Esben; Turon, A.;

    2015-01-01

    A novel computational method for simulating fatigue-driven delamination cracks in composite laminated structures under cyclic loading based on a cohesive zone model [2] and new benchmark studies with four other comparable methods [3-6] are presented. The benchmark studies describe and compare...... the traction-separation response in the cohesive zone and the transition phase from quasistatic to fatigue loading for each method. Furthermore, the accuracy of the predicted crack growth rate is studied and compared for each method. It is shown that the method described in [2] is significantly more accurate...... than the other methods [3-6]. Finally, studies are presented of the dependency and sensitivity to the change in different quasi-static material parameters and model specific fitting parameters. It is shown that all the methods except [2] rely on different parameters which are not possible to determine...

  19. Benchmark simulation Model no 2 in Matlab-simulink: towards plant-wide WWTP control strategy evaluation.

    Science.gov (United States)

    Vreck, D; Gernaey, K V; Rosen, C; Jeppsson, U

    2006-01-01

    In this paper, implementation of the Benchmark Simulation Model No 2 (BSM2) within Matlab-Simulink is presented. The BSM2 is developed for plant-wide WWTP control strategy evaluation on a long-term basis. It consists of a pre-treatment process, an activated sludge process and sludge treatment processes. Extended evaluation criteria are proposed for plant-wide control strategy assessment. Default open-loop and closed-loop strategies are also proposed to be used as references with which to compare other control strategies. Simulations indicate that the BM2 is an appropriate tool for plant-wide control strategy evaluation.

  20. Modelling anaerobic co-digestion in Benchmark Simulation Model No. 2: Parameter estimation, substrate characterisation and plant-wide integration.

    Science.gov (United States)

    Arnell, Magnus; Astals, Sergi; Åmand, Linda; Batstone, Damien J; Jensen, Paul D; Jeppsson, Ulf

    2016-07-01

    Anaerobic co-digestion is an emerging practice at wastewater treatment plants (WWTPs) to improve the energy balance and integrate waste management. Modelling of co-digestion in a plant-wide WWTP model is a powerful tool to assess the impact of co-substrate selection and dose strategy on digester performance and plant-wide effects. A feasible procedure to characterise and fractionate co-substrates COD for the Benchmark Simulation Model No. 2 (BSM2) was developed. This procedure is also applicable for the Anaerobic Digestion Model No. 1 (ADM1). Long chain fatty acid inhibition was included in the ADM1 model to allow for realistic modelling of lipid rich co-substrates. Sensitivity analysis revealed that, apart from the biodegradable fraction of COD, protein and lipid fractions are the most important fractions for methane production and digester stability, with at least two major failure modes identified through principal component analysis (PCA). The model and procedure were tested on bio-methane potential (BMP) tests on three substrates, each rich on carbohydrates, proteins or lipids with good predictive capability in all three cases. This model was then applied to a plant-wide simulation study which confirmed the positive effects of co-digestion on methane production and total operational cost. Simulations also revealed the importance of limiting the protein load to the anaerobic digester to avoid ammonia inhibition in the digester and overloading of the nitrogen removal processes in the water train. In contrast, the digester can treat relatively high loads of lipid rich substrates without prolonged disturbances.

  1. Towards a plant-wide Benchmark Simulation Model with simultaneous nitrogen and phosphorus removal wastewater treatment processes

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Ikumi, David; Batstone, Damien

    . This extension aims at facilitating simultaneous carbon, nitrogen and phosphorus (P) removal process development and performance evaluation at a plant-wide level. The main motivation of the work is that numerous wastewater treatment plants (WWTPs) pursue biological phosphorus removal as an alternative......It is more than 10 years since the publication of the Benchmark Simulation Model No 1 (BSM1) manual (Copp, 2002). The main objective of BSM1 was creating a platform for benchmarking carbon and nitrogen removal strategies in activated sludge systems. The initial platform evolved into BSM1_LT and BSM...... to chemical P removal based on precipitation using metal salts, such as Fe or Al. This paper identifies and discusses important issues that need to be addressed to upgrade the BSM2 to BSM2-P, for example: 1) new influent wastewater characteristics; 2) new (bio) chemical processes to account for; 3...

  2. A framework of benchmarking land models

    Science.gov (United States)

    Luo, Y. Q.; Randerson, J.; Abramowitz, G.; Bacour, C.; Blyth, E.; Carvalhais, N.; Ciais, P.; Dalmonech, D.; Fisher, J.; Fisher, R.; Friedlingstein, P.; Hibbard, K.; Hoffman, F.; Huntzinger, D.; Jones, C. D.; Koven, C.; Lawrence, D.; Li, D. J.; Mahecha, M.; Niu, S. L.; Norby, R.; Piao, S. L.; Qi, X.; Peylin, P.; Prentice, I. C.; Riley, W.; Reichstein, M.; Schwalm, C.; Wang, Y. P.; Xia, J. Y.; Zaehle, S.; Zhou, X. H.

    2012-02-01

    Land models, which have been developed by the modeling community in the past two decades to predict future states of ecosystems and climate, have to be critically evaluated for their performance skills of simulating ecosystem responses and feedback to climate change. Benchmarking is an emerging procedure to measure and evaluate performance of models against a set of defined standards. This paper proposes a benchmarking framework for evaluation of land models. The framework includes (1) targeted aspects of model performance to be evaluated; (2) a set of benchmarks as defined references to test model performance; (3) metrics to measure and compare performance skills among models so as to identify model strengths and deficiencies; and (4) model improvement. Component 4 may or may not be involved in a benchmark analysis but is an ultimate goal of general modeling research. Land models are required to simulate exchange of water, energy, carbon and sometimes other trace gases between the atmosphere and the land-surface, and should be evaluated for their simulations of biophysical processes, biogeochemical cycles, and vegetation dynamics across timescales in response to both weather and climate change. Benchmarks that are used to evaluate models generally consist of direct observations, data-model products, and data-derived patterns and relationships. Metrics of measuring mismatches between models and benchmarks may include (1) a priori thresholds of acceptable model performance and (2) a scoring system to combine data-model mismatches for various processes at different temporal and spatial scales. The benchmark analyses should identify clues of weak model performance for future improvement. Iterations between model evaluation and improvement via benchmarking shall demonstrate progress of land modeling and help establish confidence in land models for their predictions of future states of ecosystems and climate.

  3. A framework of benchmarking land models

    Directory of Open Access Journals (Sweden)

    Y. Q. Luo

    2012-02-01

    Full Text Available Land models, which have been developed by the modeling community in the past two decades to predict future states of ecosystems and climate, have to be critically evaluated for their performance skills of simulating ecosystem responses and feedback to climate change. Benchmarking is an emerging procedure to measure and evaluate performance of models against a set of defined standards. This paper proposes a benchmarking framework for evaluation of land models. The framework includes (1 targeted aspects of model performance to be evaluated; (2 a set of benchmarks as defined references to test model performance; (3 metrics to measure and compare performance skills among models so as to identify model strengths and deficiencies; and (4 model improvement. Component 4 may or may not be involved in a benchmark analysis but is an ultimate goal of general modeling research. Land models are required to simulate exchange of water, energy, carbon and sometimes other trace gases between the atmosphere and the land-surface, and should be evaluated for their simulations of biophysical processes, biogeochemical cycles, and vegetation dynamics across timescales in response to both weather and climate change. Benchmarks that are used to evaluate models generally consist of direct observations, data-model products, and data-derived patterns and relationships. Metrics of measuring mismatches between models and benchmarks may include (1 a priori thresholds of acceptable model performance and (2 a scoring system to combine data-model mismatches for various processes at different temporal and spatial scales. The benchmark analyses should identify clues of weak model performance for future improvement. Iterations between model evaluation and improvement via benchmarking shall demonstrate progress of land modeling and help establish confidence in land models for their predictions of future states of ecosystems and climate.

  4. Quo Vadis Benchmark Simulation Models? 8th IWA Symposium on Systems Analysis and Integrated Assessment

    DEFF Research Database (Denmark)

    Jeppsson, U.; Alex, J.; Batstone, D,;

    2011-01-01

    As the work of the IWA Task Group on Benchmarking of Control Strategies for WWTPs is coming towards an end, it is essential to disseminate the knowledge gained. For this reason, all authors of the IWA Scientific and Technical Report on benchmarking have come together to provide their insights, hi...

  5. A framework for benchmarking land models

    Science.gov (United States)

    Luo, Y. Q.; Randerson, J. T.; Abramowitz, G.; Bacour, C.; Blyth, E.; Carvalhais, N.; Ciais, P.; Dalmonech, D.; Fisher, J. B.; Fisher, R.; Friedlingstein, P.; Hibbard, K.; Hoffman, F.; Huntzinger, D.; Jones, C. D.; Koven, C.; Lawrence, D.; Li, D. J.; Mahecha, M.; Niu, S. L.; Norby, R.; Piao, S. L.; Qi, X.; Peylin, P.; Prentice, I. C.; Riley, W.; Reichstein, M.; Schwalm, C.; Wang, Y. P.; Xia, J. Y.; Zaehle, S.; Zhou, X. H.

    2012-10-01

    Land models, which have been developed by the modeling community in the past few decades to predict future states of ecosystems and climate, have to be critically evaluated for their performance skills of simulating ecosystem responses and feedback to climate change. Benchmarking is an emerging procedure to measure performance of models against a set of defined standards. This paper proposes a benchmarking framework for evaluation of land model performances and, meanwhile, highlights major challenges at this infant stage of benchmark analysis. The framework includes (1) targeted aspects of model performance to be evaluated, (2) a set of benchmarks as defined references to test model performance, (3) metrics to measure and compare performance skills among models so as to identify model strengths and deficiencies, and (4) model improvement. Land models are required to simulate exchange of water, energy, carbon and sometimes other trace gases between the atmosphere and land surface, and should be evaluated for their simulations of biophysical processes, biogeochemical cycles, and vegetation dynamics in response to climate change across broad temporal and spatial scales. Thus, one major challenge is to select and define a limited number of benchmarks to effectively evaluate land model performance. The second challenge is to develop metrics of measuring mismatches between models and benchmarks. The metrics may include (1) a priori thresholds of acceptable model performance and (2) a scoring system to combine data-model mismatches for various processes at different temporal and spatial scales. The benchmark analyses should identify clues of weak model performance to guide future development, thus enabling improved predictions of future states of ecosystems and climate. The near-future research effort should be on development of a set of widely acceptable benchmarks that can be used to objectively, effectively, and reliably evaluate fundamental properties of land models

  6. A framework for benchmarking land models

    Directory of Open Access Journals (Sweden)

    Y. Q. Luo

    2012-10-01

    Full Text Available Land models, which have been developed by the modeling community in the past few decades to predict future states of ecosystems and climate, have to be critically evaluated for their performance skills of simulating ecosystem responses and feedback to climate change. Benchmarking is an emerging procedure to measure performance of models against a set of defined standards. This paper proposes a benchmarking framework for evaluation of land model performances and, meanwhile, highlights major challenges at this infant stage of benchmark analysis. The framework includes (1 targeted aspects of model performance to be evaluated, (2 a set of benchmarks as defined references to test model performance, (3 metrics to measure and compare performance skills among models so as to identify model strengths and deficiencies, and (4 model improvement. Land models are required to simulate exchange of water, energy, carbon and sometimes other trace gases between the atmosphere and land surface, and should be evaluated for their simulations of biophysical processes, biogeochemical cycles, and vegetation dynamics in response to climate change across broad temporal and spatial scales. Thus, one major challenge is to select and define a limited number of benchmarks to effectively evaluate land model performance. The second challenge is to develop metrics of measuring mismatches between models and benchmarks. The metrics may include (1 a priori thresholds of acceptable model performance and (2 a scoring system to combine data–model mismatches for various processes at different temporal and spatial scales. The benchmark analyses should identify clues of weak model performance to guide future development, thus enabling improved predictions of future states of ecosystems and climate. The near-future research effort should be on development of a set of widely acceptable benchmarks that can be used to objectively, effectively, and reliably evaluate fundamental properties

  7. A proposed benchmark for simulation in radiographic testing

    Energy Technology Data Exchange (ETDEWEB)

    Jaenisch, G.-R.; Deresch, A.; Bellon, C. [Federal Institute for Materials Research and Testing Unter den Eichen 87, 12205 Berlin (Germany); Schumm, A.; Guerin, P. [EDF R and D, 1 avenue du Général de Gaulle, 92141 Clamart (France)

    2014-02-18

    The purpose of this benchmark study is to compare simulation results predicted by various models of radiographic testing, in particular those that are capable of separately predicting primary and scatter radiation for specimens of arbitrary geometry.

  8. A Benchmark and Simulator for UAV Tracking

    KAUST Repository

    Mueller, Matthias

    2016-09-16

    In this paper, we propose a new aerial video dataset and benchmark for low altitude UAV target tracking, as well as, a photorealistic UAV simulator that can be coupled with tracking methods. Our benchmark provides the first evaluation of many state-of-the-art and popular trackers on 123 new and fully annotated HD video sequences captured from a low-altitude aerial perspective. Among the compared trackers, we determine which ones are the most suitable for UAV tracking both in terms of tracking accuracy and run-time. The simulator can be used to evaluate tracking algorithms in real-time scenarios before they are deployed on a UAV “in the field”, as well as, generate synthetic but photo-realistic tracking datasets with automatic ground truth annotations to easily extend existing real-world datasets. Both the benchmark and simulator are made publicly available to the vision community on our website to further research in the area of object tracking from UAVs. (https://ivul.kaust.edu.sa/Pages/pub-benchmark-simulator-uav.aspx.). © Springer International Publishing AG 2016.

  9. Towards Systematic Benchmarking of Climate Model Performance

    Science.gov (United States)

    Gleckler, P. J.

    2014-12-01

    The process by which climate models are evaluated has evolved substantially over the past decade, with the Coupled Model Intercomparison Project (CMIP) serving as a centralizing activity for coordinating model experimentation and enabling research. Scientists with a broad spectrum of expertise have contributed to the CMIP model evaluation process, resulting in many hundreds of publications that have served as a key resource for the IPCC process. For several reasons, efforts are now underway to further systematize some aspects of the model evaluation process. First, some model evaluation can now be considered routine and should not require "re-inventing the wheel" or a journal publication simply to update results with newer models. Second, the benefit of CMIP research to model development has not been optimal because the publication of results generally takes several years and is usually not reproducible for benchmarking newer model versions. And third, there are now hundreds of model versions and many thousands of simulations, but there is no community-based mechanism for routinely monitoring model performance changes. An important change in the design of CMIP6 can help address these limitations. CMIP6 will include a small set standardized experiments as an ongoing exercise (CMIP "DECK": ongoing Diagnostic, Evaluation and Characterization of Klima), so that modeling groups can submit them at any time and not be overly constrained by deadlines. In this presentation, efforts to establish routine benchmarking of existing and future CMIP simulations will be described. To date, some benchmarking tools have been made available to all CMIP modeling groups to enable them to readily compare with CMIP5 simulations during the model development process. A natural extension of this effort is to make results from all CMIP simulations widely available, including the results from newer models as soon as the simulations become available for research. Making the results from routine

  10. Concrete Model Descriptions and Summary of Benchmark Studies for Blast Effects Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Noble, C; Kokko, E; Darnell, I; Dunn, T; Hagler, L; Leininger, L

    2005-07-21

    Concrete is perhaps one of the most widely used construction materials in the world. Engineers use it to build massive concrete dams, concrete waterways, highways, bridges, and even nuclear reactors. The advantages of using concrete is that it can be cast into any desired shape, it is durable, and very economical compared to structural steel. The disadvantages are its low tensile strength, low ductility, and low strength-to-weight ratio. Concrete is a composite material that consists of a coarse granular material, or aggregate, embedded in a hard matrix of material, or cement, which fills the gaps between the aggregates and binds them together. Concrete properties, however, vary widely. The properties depend on the choice of materials used and the proportions for a particular application, as well as differences in fabrication techniques. Table 1 provides a listing of typical engineering properties for structural concrete. Properties also depend on the level of concrete confinement, or hydrostatic pressure, the material is being subjected to. In general, concrete is rarely subjected to a single axial stress. The material may experience a combination of stresses all acting simultaneously. The behavior of concrete under these combined stresses are, however, extremely difficult to characterize. In addition to the type of loading, one must also consider the stress history of the material. Failure is determined not only by the ultimate stresses, but also by the rate of loading and the order in which these stresses were applied. The concrete model described herein accounts for this complex behavior of concrete. It was developed by Javier Malvar, Jim Wesevich, and John Crawford of Karagozian and Case, and Don Simon of Logicon RDA in support of the Defense Threat Reduction Agency's programs. The model is an enhanced version of the Concrete/Geological Material Model 16 in the Lagrangian finite element code DYNA3D. The modifications that were made to the original model

  11. Simulation with Different Turbulence Models in an Annex 20 Benchmark Test using Star-CCM+

    DEFF Research Database (Denmark)

    Le Dreau, Jerome; Heiselberg, Per; Nielsen, Peter V.

    The purpose of this investigation is to compare the different flow patterns obtained for the 2D isothermal test case defined in Annex 20 (1990) using different turbulence models. The different results are compared with the existing experimental data. Similar study has already been performed by Rong...... et al. (2008) using Ansys CFX 11.0. In this report, the software Star-CCM+ has been used....

  12. On a new benchmark for the simulation of saltwater intrusion

    Science.gov (United States)

    Stoeckl, Leonard; Graf, Thomas

    2015-04-01

    To date, many different benchmark problems for density-driven flow are available. Benchmarks are necessary to validate numerical models. The benchmark by Henry (1964) measures a saltwater wedge, intruding into a freshwater aquifer in a rectangular model. The Henry (1964) problem of saltwater intrusion is one of the most applied benchmarks in hydrogeology. Modelling saltwater intrusion will be of major importance in the future because investigating the impact of groundwater overexploitation, climate change or sea level rise are of key concern. The worthiness of the Henry (1964) problem was questioned by Simpson and Clement (2003), who compared density-coupled and density-uncoupled simulations. Density-uncoupling was achieved by neglecting density effects in the governing equations, and by considering density effects only in the flow boundary conditions. As both of their simulations showed similar results, Simpson and Clement (2003) concluded that flow patterns of the Henry (1964) problem are largely dictated by the applied flow boundary conditions and density-dependent effects are not adequately represented in the Henry (1964) problem. In the present study, we compare numerical simulations of the physical benchmark of a freshwater lens by Stoeckl and Houben (2012) to the Henry (1964) problem. In this new benchmark, the development of a freshwater lens under an island is simulated by applying freshwater recharge to the model top. Results indicate that density-uncoupling significantly alters the flow patterns of fresh- and saltwater. This leads to the conclusion that next to the boundary conditions applied, density-dependent effects are important to correctly simulate the flow dynamics of a freshwater lens.

  13. BENCHMARKING LEARNER EDUCATION USING ONLINE BUSINESS SIMULATION

    Directory of Open Access Journals (Sweden)

    Alfred H. Miller

    2016-06-01

    Full Text Available For programmatic accreditation by the Accreditation Council of Business Schools and Programs (ACBSP, business programs are required to meet STANDARD #4, Measurement and Analysis of Student Learning and Performance. Business units must demonstrate that outcome assessment systems are in place using documented evidence that shows how the results are being used to further develop or improve the academic business program. The Higher Colleges of Technology, a 17 campus federal university in the United Arab Emirates, differentiates its applied degree programs through a ‘learning by doing ethos,’ which permeates the entire curricula. This paper documents benchmarking of education for managing innovation. Using business simulation for Bachelors of Business, Year 3 learners, in a business strategy class; learners explored through a simulated environment the following functional areas; research and development, production, and marketing of a technology product. Student teams were required to use finite resources and compete against other student teams in the same universe. The study employed an instrument developed in a 60-sample pilot study of business simulation learners against which subsequent learners participating in online business simulation could be benchmarked. The results showed incremental improvement in the program due to changes made in assessment strategies, including the oral defense.

  14. Benchmark Data Set for Wheat Growth Models: Field Experiments and AgMIP Multi-Model Simulations.

    Science.gov (United States)

    Asseng, S.; Ewert, F.; Martre, P.; Rosenzweig, C.; Jones, J. W.; Hatfield, J. L.; Ruane, A. C.; Boote, K. J.; Thorburn, P.J.; Rotter, R. P.

    2015-01-01

    The data set includes a current representative management treatment from detailed, quality-tested sentinel field experiments with wheat from four contrasting environments including Australia, The Netherlands, India and Argentina. Measurements include local daily climate data (solar radiation, maximum and minimum temperature, precipitation, surface wind, dew point temperature, relative humidity, and vapor pressure), soil characteristics, frequent growth, nitrogen in crop and soil, crop and soil water and yield components. Simulations include results from 27 wheat models and a sensitivity analysis with 26 models and 30 years (1981-2010) for each location, for elevated atmospheric CO2 and temperature changes, a heat stress sensitivity analysis at anthesis, and a sensitivity analysis with soil and crop management variations and a Global Climate Model end-century scenario.

  15. Benchmarking Benchmarks

    NARCIS (Netherlands)

    D.C. Blitz (David)

    2011-01-01

    textabstractBenchmarking benchmarks is a bundle of six studies that are inspired by the prevalence of benchmarking in academic finance research as well as in investment practice. Three studies examine if current benchmark asset pricing models adequately describe the cross-section of stock returns. W

  16. Impact on sludge inventory and control strategies using the benchmark simulation model no. 1 with the Bürger-Diehl settler model.

    Science.gov (United States)

    Torfs, E; Maere, T; Bürger, R; Diehl, S; Nopens, I

    2015-01-01

    An improved one-dimensional (1-D) model for the secondary clarifier, i.e. the Bürger-Diehl model, was recently presented. The decisive difference to traditional layer models is that every detail of the implementation is in accordance with the theory of partial differential equations. The Bürger-Diehl model allows accounting for hindered and compressive settling as well as inlet dispersion. In this contribution, the impact of specific features of the Bürger-Diehl model on settler underflow concentration predictions, plant sludge inventory and mixed liquor suspended solids based control actions are investigated by using the benchmark simulation model no. 1. The numerical results show that the Bürger-Diehl model allows for more realistic predictions of the underflow sludge concentration, which is essential for more accurate wet weather modelling and sludge waste predictions. The choice of secondary settler model clearly has a profound impact on the operation and control of the entire treatment plant and it is recommended to use the Bürger-Diehl model as of now in any wastewater treatment plant modelling effort.

  17. Baseline and benchmark model development for hotels

    Science.gov (United States)

    Hooks, Edward T., Jr.

    The hotel industry currently faces rising energy costs and requires the tools to maximize energy efficiency. In order to achieve this goal a clear definition of the current methods used to measure and monitor energy consumption is made. Uncovering the limitations to the most common practiced analysis strategies and presenting methods that can potentially overcome those limitations is the main purpose. Techniques presented can be used for measurement and verification of energy efficiency plans and retrofits. Also, modern energy modeling tool are introduced to demonstrate how they can be utilized for benchmarking and baseline models. This will provide the ability to obtain energy saving recommendations and parametric analysis to explore energy savings potential. These same energy models can be used in design decisions for new construction. An energy model is created of a resort style hotel that over one million square feet and has over one thousand rooms. A simulation and detailed analysis is performed on a hotel room. The planning process for creating the model and acquiring data from the hotel room to calibrate and verify the simulation will be explained. An explanation as to how this type of modeling can potentially be beneficial for future baseline and benchmarking strategies for the hotel industry. Ultimately the conclusion will address some common obstacles the hotel industry has in reaching their full potential of energy efficiency and how these techniques can best serve them.

  18. A chemical EOR benchmark study of different reservoir simulators

    Science.gov (United States)

    Goudarzi, Ali; Delshad, Mojdeh; Sepehrnoori, Kamy

    2016-09-01

    Interest in chemical EOR processes has intensified in recent years due to the advancements in chemical formulations and injection techniques. Injecting Polymer (P), surfactant/polymer (SP), and alkaline/surfactant/polymer (ASP) are techniques for improving sweep and displacement efficiencies with the aim of improving oil production in both secondary and tertiary floods. There has been great interest in chemical flooding recently for different challenging situations. These include high temperature reservoirs, formations with extreme salinity and hardness, naturally fractured carbonates, and sandstone reservoirs with heavy and viscous crude oils. More oil reservoirs are reaching maturity where secondary polymer floods and tertiary surfactant methods have become increasingly important. This significance has added to the industry's interest in using reservoir simulators as tools for reservoir evaluation and management to minimize costs and increase the process efficiency. Reservoir simulators with special features are needed to represent coupled chemical and physical processes present in chemical EOR processes. The simulators need to be first validated against well controlled lab and pilot scale experiments to reliably predict the full field implementations. The available data from laboratory scale include 1) phase behavior and rheological data; and 2) results of secondary and tertiary coreflood experiments for P, SP, and ASP floods under reservoir conditions, i.e. chemical retentions, pressure drop, and oil recovery. Data collected from corefloods are used as benchmark tests comparing numerical reservoir simulators with chemical EOR modeling capabilities such as STARS of CMG, ECLIPSE-100 of Schlumberger, REVEAL of Petroleum Experts. The research UTCHEM simulator from The University of Texas at Austin is also included since it has been the benchmark for chemical flooding simulation for over 25 years. The results of this benchmark comparison will be utilized to improve

  19. FRIB driver linac vacuum model and benchmarks

    CERN Document Server

    Durickovic, Bojan; Kersevan, Roberto; Machicoane, Guillaume

    2014-01-01

    The Facility for Rare Isotope Beams (FRIB) is a superconducting heavy-ion linear accelerator that is to produce rare isotopes far from stability for low energy nuclear science. In order to achieve this, its driver linac needs to achieve a very high beam current (up to 400 kW beam power), and this requirement makes vacuum levels of critical importance. Vacuum calculations have been carried out to verify that the vacuum system design meets the requirements. The modeling procedure was benchmarked by comparing models of an existing facility against measurements. In this paper, we present an overview of the methods used for FRIB vacuum calculations and simulation results for some interesting sections of the accelerator. (C) 2013 Elsevier Ltd. All rights reserved.

  20. Towards benchmarking an in-stream water quality model

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available A method of model evaluation is presented which utilises a comparison with a benchmark model. The proposed benchmarking concept is one that can be applied to many hydrological models but, in this instance, is implemented in the context of an in-stream water quality model. The benchmark model is defined in such a way that it is easily implemented within the framework of the test model, i.e. the approach relies on two applications of the same model code rather than the application of two separate model codes. This is illustrated using two case studies from the UK, the Rivers Aire and Ouse, with the objective of simulating a water quality classification, general quality assessment (GQA, which is based on dissolved oxygen, biochemical oxygen demand and ammonium. Comparisons between the benchmark and test models are made based on GQA, as well as a step-wise assessment against the components required in its derivation. The benchmarking process yields a great deal of important information about the performance of the test model and raises issues about a priori definition of the assessment criteria.

  1. Results of the benchmark for blade structural models, part A

    DEFF Research Database (Denmark)

    Lekou, D.J.; Chortis, D.; Belen Fariñas, A.;

    2013-01-01

    Task 2.2 of the InnWind.Eu project. The benchmark is based on the reference wind turbine and the reference blade provided by DTU [1]. "Structural Concept developers/modelers" of WP2 were provided with the necessary input for a comparison numerical simulation run, upon definition of the reference blade......A benchmark on structural design methods for blades was performed within the InnWind.Eu project under WP2 “Lightweight Rotor” Task 2.2 “Lightweight structural design”. The present document is describes the results of the comparison simulation runs that were performed by the partners involved within...

  2. A comprehensive benchmarking system for evaluating global vegetation models

    Directory of Open Access Journals (Sweden)

    D. I. Kelley

    2012-11-01

    Full Text Available We present a benchmark system for global vegetation models. This system provides a quantitative evaluation of multiple simulated vegetation properties, including primary production; seasonal net ecosystem production; vegetation cover, composition and height; fire regime; and runoff. The benchmarks are derived from remotely sensed gridded datasets and site-based observations. The datasets allow comparisons of annual average conditions and seasonal and inter-annual variability, and they allow the impact of spatial and temporal biases in means and variability to be assessed separately. Specifically designed metrics quantify model performance for each process, and are compared to scores based on the temporal or spatial mean value of the observations and a "random" model produced by bootstrap resampling of the observations. The benchmark system is applied to three models: a simple light-use efficiency and water-balance model (the Simple Diagnostic Biosphere Model: SDBM, and the Lund-Potsdam-Jena (LPJ and Land Processes and eXchanges (LPX dynamic global vegetation models (DGVMs. SDBM reproduces observed CO2 seasonal cycles, but its simulation of independent measurements of net primary production (NPP is too high. The two DGVMs show little difference for most benchmarks (including the inter-annual variability in the growth rate and seasonal cycle of atmospheric CO2, but LPX represents burnt fraction demonstrably more accurately. Benchmarking also identified several weaknesses common to both DGVMs. The benchmarking system provides a quantitative approach for evaluating how adequately processes are represented in a model, identifying errors and biases, tracking improvements in performance through model development, and discriminating among models. Adoption of such a system would do much to improve confidence in terrestrial model predictions of climate change impacts and feedbacks.

  3. Benchmarking of Proton Transport in Super Monte Carlo Simulation Program

    Science.gov (United States)

    Wang, Yongfeng; Li, Gui; Song, Jing; Zheng, Huaqing; Sun, Guangyao; Hao, Lijuan; Wu, Yican

    2014-06-01

    reactions for proton. Some other hadronic models are also being developed now. The benchmarking of proton transport in SuperMC has been performed according to Accelerator Driven subcritical System (ADS) benchmark data and model released by IAEA from IAEA's Cooperation Research Plan (CRP). The incident proton energy is 1.0 GeV. The neutron flux and energy deposition were calculated. The results simulated using SupeMC and FLUKA are in agreement within the statistical uncertainty inherent in the Monte Carlo method. The proton transport in SuperMC has also been applied in China Lead-Alloy cooled Reactor (CLEAR), which is designed by FDS Team for the calculation of spallation reaction in the target.

  4. Reactive transport benchmarks for subsurface environmental simulation

    Energy Technology Data Exchange (ETDEWEB)

    Steefel, Carl I.; Yabusaki, Steven B.; Mayer, K. U.

    2015-06-01

    Over the last 20 years, we have seen firsthand the evolution of multicomponent reactive transport modeling and the expanding range and increasing complexity of subsurface applications it is being used to address. There is a growing reliance on reactive transport modeling (RTM) to address some of the most compelling issues facing our planet: climate change, nuclear waste management, contaminant remediation, and pollution prevention. While these issues are motivating the development of new and improved capabilities for subsurface environmental modeling using RTM (e.g., biogeochemistry from cell-scale physiology to continental-scale terrestrial ecosystems, nonisothermal multiphase conditions, coupled geomechanics), there remain longstanding challenges in characterizing the natural variability of hydrological, biological, and geochemical properties in subsurface environments and limited success in transferring models between sites and across scales. An equally important trend over the last 20 years is the evolution of modeling from a service sought out after data has been collected to a multifaceted research approach that provides (1) an organizing principle for characterization and monitoring activities; (2) a systematic framework for identifying knowledge gaps, developing and integrating new knowledge; and (3) a mechanistic understanding that represents the collective wisdom of the participating scientists and engineers. There are now large multidisciplinary projects where the research approach is model-driven, and the principal product is a holistic predictive simulation capability that can be used as a test bed for alternative conceptualizations of processes, properties, and conditions. Much of the future growth and expanded role for RTM will depend on its continued ability to exploit technological advancements in the earth and environmental sciences. Advances in measurement technology, particularly in molecular biology (genomics), isotope fractionation, and high

  5. Implementing ADM1 for plant-wide benchmark simulations in Matlab/Simulink

    DEFF Research Database (Denmark)

    Rosen, Christian; Vrecko, Darko; Gernaey, Krist

    2006-01-01

    , in particular if the ADM1 is to be included in dynamic simulations of plant-wide or even integrated systems. In this paper, the experiences gained from a Matlab/Simulink implementation of ADM1 into the extended COST/IWA Benchmark Simulation Model (BSM2) are presented. Aspects related to system stiffness, model...

  6. SPOC Benchmark Case: SNRE Model

    Energy Technology Data Exchange (ETDEWEB)

    Vishal Patel; Michael Eades; Claude Russel Joyner II

    2016-02-01

    The Small Nuclear Rocket Engine (SNRE) was modeled in the Center for Space Nuclear Research’s (CSNR) Space Propulsion Optimization Code (SPOC). SPOC aims to create nuclear thermal propulsion (NTP) geometries quickly to perform parametric studies on design spaces of historic and new NTP designs. The SNRE geometry was modeled in SPOC and a critical core with a reasonable amount of criticality margin was found. The fuel, tie-tubes, reflector, and control drum masses were predicted rather well. These are all very important for neutronics calculations so the active reactor geometries created with SPOC can continue to be trusted. Thermal calculations of the average and hot fuel channels agreed very well. The specific impulse calculations used historically and in SPOC disagree so mass flow rates and impulses differed. Modeling peripheral and power balance components that do not affect nuclear characteristics of the core is not a feature of SPOC and as such, these components should continue to be designed using other tools. A full paper detailing the available SNRE data and comparisons with SPOC outputs will be submitted as a follow-up to this abstract.

  7. Shear Strength Measurement Benchmarking Tests for K Basin Sludge Simulants

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Carolyn A.; Daniel, Richard C.; Enderlin, Carl W.; Luna, Maria; Schmidt, Andrew J.

    2009-06-10

    Equipment development and demonstration testing for sludge retrieval is being conducted by the K Basin Sludge Treatment Project (STP) at the MASF (Maintenance and Storage Facility) using sludge simulants. In testing performed at the Pacific Northwest National Laboratory (under contract with the CH2M Hill Plateau Remediation Company), the performance of the Geovane instrument was successfully benchmarked against the M5 Haake rheometer using a series of simulants with shear strengths (τ) ranging from about 700 to 22,000 Pa (shaft corrected). Operating steps for obtaining consistent shear strength measurements with the Geovane instrument during the benchmark testing were refined and documented.

  8. Understanding N2O formation mechanisms through sensitivity analyses using a plant-wide benchmark simulation model

    DEFF Research Database (Denmark)

    Boiocchi, Riccardo; Gernaey, Krist; Sin, Gürkan

    2017-01-01

    the biological mechanisms responsible for N2O emissions,TN removal efficiency, competition for oxygen among the different microbial groups and the trade-off between oxygen consumption and effluent nitrogen loading. It was found that N2O emissions are triggered by poor oxygenation levels which cause an imbalance......In the present work, sensitivity analyses are performed on a plant-wide model incorporating the typical treatment unit of a full-scale wastewater treatment plant and N2O production and emission dynamics. The influence of operating temperatureis investigated. The results are exploited to identify...

  9. Benchmarking analogue models of brittle thrust wedges

    Science.gov (United States)

    Schreurs, Guido; Buiter, Susanne J. H.; Boutelier, Jennifer; Burberry, Caroline; Callot, Jean-Paul; Cavozzi, Cristian; Cerca, Mariano; Chen, Jian-Hong; Cristallini, Ernesto; Cruden, Alexander R.; Cruz, Leonardo; Daniel, Jean-Marc; Da Poian, Gabriela; Garcia, Victor H.; Gomes, Caroline J. S.; Grall, Céline; Guillot, Yannick; Guzmán, Cecilia; Hidayah, Triyani Nur; Hilley, George; Klinkmüller, Matthias; Koyi, Hemin A.; Lu, Chia-Yu; Maillot, Bertrand; Meriaux, Catherine; Nilfouroushan, Faramarz; Pan, Chang-Chih; Pillot, Daniel; Portillo, Rodrigo; Rosenau, Matthias; Schellart, Wouter P.; Schlische, Roy W.; Take, Andy; Vendeville, Bruno; Vergnaud, Marine; Vettori, Matteo; Wang, Shih-Hsien; Withjack, Martha O.; Yagupsky, Daniel; Yamada, Yasuhiro

    2016-11-01

    We performed a quantitative comparison of brittle thrust wedge experiments to evaluate the variability among analogue models and to appraise the reproducibility and limits of model interpretation. Fifteen analogue modeling laboratories participated in this benchmark initiative. Each laboratory received a shipment of the same type of quartz and corundum sand and all laboratories adhered to a stringent model building protocol and used the same type of foil to cover base and sidewalls of the sandbox. Sieve structure, sifting height, filling rate, and details on off-scraping of excess sand followed prescribed procedures. Our analogue benchmark shows that even for simple plane-strain experiments with prescribed stringent model construction techniques, quantitative model results show variability, most notably for surface slope, thrust spacing and number of forward and backthrusts. One of the sources of the variability in model results is related to slight variations in how sand is deposited in the sandbox. Small changes in sifting height, sifting rate, and scraping will result in slightly heterogeneous material bulk densities, which will affect the mechanical properties of the sand, and will result in lateral and vertical differences in peak and boundary friction angles, as well as cohesion values once the model is constructed. Initial variations in basal friction are inferred to play the most important role in causing model variability. Our comparison shows that the human factor plays a decisive role, and even when one modeler repeats the same experiment, quantitative model results still show variability. Our observations highlight the limits of up-scaling quantitative analogue model results to nature or for making comparisons with numerical models. The frictional behavior of sand is highly sensitive to small variations in material state or experimental set-up, and hence, it will remain difficult to scale quantitative results such as number of thrusts, thrust spacing

  10. Simulation of Benchmark Cases with the Terminal Area Simulation System (TASS)

    Science.gov (United States)

    Ahmad, Nash'at; Proctor, Fred

    2011-01-01

    The hydrodynamic core of the Terminal Area Simulation System (TASS) is evaluated against different benchmark cases. In the absence of closed form solutions for the equations governing atmospheric flows, the models are usually evaluated against idealized test cases. Over the years, various authors have suggested a suite of these idealized cases which have become standards for testing and evaluating the dynamics and thermodynamics of atmospheric flow models. In this paper, simulations of three such cases are described. In addition, the TASS model is evaluated against a test case that uses an exact solution of the Navier-Stokes equations. The TASS results are compared against previously reported simulations of these banchmark cases in the literature. It is demonstrated that the TASS model is highly accurate, stable and robust.

  11. 基于Benchmarking技术的汽车侧面碰撞建模与仿真试验%Modeling and Simulation Test of Car Side Impact Based on Benchmarking Technology

    Institute of Scientific and Technical Information of China (English)

    徐中明; 张亮; 范体强; 赵清江

    2012-01-01

    介绍了Benchmarking技术的概念和基本工作流程,并根据某车型所进行的Benchmarking数据,建立了包括车身结构、发动机和底盘系统在内的整车有限元分析模型.根据ECE R95法规进行了整车侧面碰撞仿真试验,通过对比仿真试验的结果与实车侧面碰撞试验的结果,验证了模型的有效性.本文的研究方法为Benchmarking技术在汽车碰撞安全分析上的应用提供了参考.%The concept and working process of benchmarking technology are introduced. According to a car benchmarking data,the finite element analysis model of a full-scale passenger car is developed, including body structure, engine and chassis system. Subsequently, the simulation test of the car side impact is conducted according to ECE R95 regulation. And the model is verified by comparing the results of simulation and test, reference of using benchmarking technology in the car crash safety analysis is provided by this research method.

  12. Holistic simulation of geotechnical installation processes benchmarks and simulations

    CERN Document Server

    2016-01-01

    This book examines in detail the entire process involved in implementing geotechnical projects, from a well-defined initial stress and deformation state, to the completion of the installation process.   The individual chapters provide the fundamental knowledge needed to effectively improve soil-structure interaction models. Further, they present the results of theoretical fundamental research on suitable constitutive models, contact formulations, and efficient numerical implementations and algorithms. Applications of fundamental research on boundary value problems are also considered in order to improve the implementation of the theoretical models developed. Subsequent chapters highlight parametric studies of the respective geotechnical installation process, as well as elementary and large-scale model tests under well-defined conditions, in order to identify the most essential parameters for optimizing the process. The book provides suitable methods for simulating boundary value problems in connection with g...

  13. Benchmarking an Unstructured-Grid Model for Tsunami Current Modeling

    Science.gov (United States)

    Zhang, Yinglong J.; Priest, George; Allan, Jonathan; Stimely, Laura

    2016-12-01

    We present model results derived from a tsunami current benchmarking workshop held by the NTHMP (National Tsunami Hazard Mitigation Program) in February 2015. Modeling was undertaken using our own 3D unstructured-grid model that has been previously certified by the NTHMP for tsunami inundation. Results for two benchmark tests are described here, including: (1) vortex structure in the wake of a submerged shoal and (2) impact of tsunami waves on Hilo Harbor in the 2011 Tohoku event. The modeled current velocities are compared with available lab and field data. We demonstrate that the model is able to accurately capture the velocity field in the two benchmark tests; in particular, the 3D model gives a much more accurate wake structure than the 2D model for the first test, with the root-mean-square error and mean bias no more than 2 cm s-1 and 8 mm s-1, respectively, for the modeled velocity.

  14. Upgrading the Benchmark Simulation Model Framework with emerging challenges - A study of N2O emissions and the fate of pharmaceuticals in urban wastewater systems

    DEFF Research Database (Denmark)

    Snip, Laura

    the performance of a WWTP can be done with mathematical models that can be used in simulation studies. The Benchmark Simulation Model (BSM) framework was developed to compare objectively different operational/control strategies. As different operational strategies of a WWTP will most likely have an effect...... on the greenhouse gas (GHG) emissions and the removal rate of micropollutants (MPs), modelling these processes for dynamic simulations and evaluation seems to be a promising tool for optimisation of a WWTP. Therefore, in this thesis the BSM is upgraded with processes describing GHG emissions and MPs removal...... for pharmaceuticals with a more random occurrence. Different sewer conditions demonstrated effects on the occurrence of the pharmaceuticals as influent patterns at the inlet of the WWTP were smoothed or delayed. The fate in the WWTP showed that operational conditions can influence the biotransformation...

  15. Community Benchmarking of Tsunami-Induced Nearshore Current Models

    Science.gov (United States)

    Lynett, P. J.; Wilson, R. I.; Gately, K.

    2015-12-01

    To help produce accurate and consistent maritime hazard products, the National Tsunami Hazard Mitigation Program (NTHMP) Strategic Plan includes a requirement to develop and run a benchmarking workshop to evaluate the numerical tsunami modeling of currents. For this workshop, five different benchmarking datasets were organized. These datasets were selected based on characteristics such as geometric complexity, currents that are shear/separation driven (and thus are de-coupled from the incident wave forcing), tidal coupling, and interaction with the built environment. While tsunami simulation models have generally been well validated against wave height and runup, comparisons with speed data are much less common. As model results are increasingly being used to estimate or indicate damage to coastal infrastructure, understanding the accuracy and precision of speed predictions becomes of important. As a result of this 2-day workshop held in early 2015, modelers now have a better awareness of their ability to accurately capture the physics of tsunami currents, and therefore a better understanding of how to use these simulation tools for hazard assessment and mitigation efforts. In this presentation, the model results - from 14 different modelers - will be presented and summarized, with a focus on statistical and ensemble properties of the current predictions.

  16. Simulation benchmark based on THAI-experiment on dissolution of a steam stratification by natural convection

    Energy Technology Data Exchange (ETDEWEB)

    Freitag, M., E-mail: freitag@becker-technologies.com; Schmidt, E.; Gupta, S.; Poss, G.

    2016-04-01

    Highlights: . • We studied the generation and dissolution of steam stratification in natural convection. • We performed a computer code benchmark including blind and open phases. • The dissolution of stratification predicted only qualitatively by LP and CFD models during the blind simulation phase. - Abstract: Locally enriched hydrogen as in stratification may contribute to early containment failure in the course of severe nuclear reactor accidents. During accident sequences steam might accumulate as well to stratifications which can directly influence the distribution and ignitability of hydrogen mixtures in containments. An international code benchmark including Computational Fluid Dynamics (CFD) and Lumped Parameter (LP) codes was conducted in the frame of the German THAI program. Basis for the benchmark was experiment TH24.3 which investigates the dissolution of a steam layer subject to natural convection in the steam-air atmosphere of the THAI vessel. The test provides validation data for the development of CFD and LP models to simulate the atmosphere in the containment of a nuclear reactor installation. In test TH24.3 saturated steam is injected into the upper third of the vessel forming a stratification layer which is then mixed by a superposed thermal convection. In this paper the simulation benchmark will be evaluated in addition to the general discussion about the experimental transient of test TH24.3. Concerning the steam stratification build-up and dilution of the stratification, the numerical programs showed very different results during the blind evaluation phase, but improved noticeable during open simulation phase.

  17. Simulation of nonlinear benchmarks and sheet metal forming processes using linear and quadratic solid–shell elements combined with advanced anisotropic behavior models

    Directory of Open Access Journals (Sweden)

    WangPeng

    2016-01-01

    Full Text Available A family of prismatic and hexahedral solid‒shell (SHB elements with their linear and quadratic versions is presented in this paper to model thin 3D structures. Based on reduced integration and special treatments to eliminate locking effects and to control spurious zero-energy modes, the SHB solid‒shell elements are capable of modeling most thin 3D structural problems with only a single element layer, while describing accurately the various through-thickness phenomena. In this paper, the SHB elements are combined with fully 3D behavior models, including orthotropic elastic behavior for composite materials and anisotropic plastic behavior for metallic materials, which allows describing the strain/stress state in the thickness direction, in contrast to traditional shell elements. All SHB elements are implemented into ABAQUS using both standard/quasi-static and explicit/dynamic solvers. Several benchmark tests have been conducted, in order to first assess the performance of the SHB elements in quasi-static and dynamic analyses. Then, deep drawing of a hemispherical cup is performed to demonstrate the capabilities of the SHB elements in handling various types of nonlinearities (large displacements and rotations, anisotropic plasticity, and contact. Compared to classical ABAQUS solid and shell elements, the results given by the SHB elements show good agreement with the reference solutions.

  18. Extending the benchmark simulation model no2 with processes for nitrous oxide production and side-stream nitrogen removal

    DEFF Research Database (Denmark)

    2015-01-01

    the Complete Autotrophic Nitrogen Removal (CANR) model was used to describe the side-stream (PN/A) treatment. Comprehensive simulations were performed to assess the extended model. Steady-state simulation results revealed the following: (i) the implementation of a continuous CANR side-stream reactor has...... strategies to improve operation performance and to meet the new plant performance criteria such as minimization of greenhouse gas (in particular of nitrous oxide) emissions....

  19. Benchmark of the bootstrap current simulation in helical plasmas

    CERN Document Server

    Huang, Botsz; Kanno, Ryutaro; Sugama, Hideo; Goto, Takuya

    2016-01-01

    The importance of the parallel momentum conservation on the bootstrap current evaluation in nonaxisymmetric systems is demonstrated by the benchmarks among the local drift-kinetic equation solvers, i.e., the Zero-Orbit-width(ZOW), DKES, and PENTA codes. The ZOW model is extended to include the ion parallel mean flow effect on the electron-ion parallel friction. Compared to the DKES model in which only the pitch-angle-scattering term is included in the collision operator, the PENTA model employs the Sugama-Nishimura method to correct the momentum balance. The ZOW and PENTA models agree each other well on the calculations of the bootstrap current. The DKES results without the parallel momentum conservation deviates significantly from those from the ZOW and PENTA models. This work verifies the reliability of the bootstrap current calculation with the ZOW and PENTA models for the helical plasmas.

  20. Microbially Mediated Kinetic Sulfur Isotope Fractionation: Reactive Transport Modeling Benchmark

    Science.gov (United States)

    Wanner, C.; Druhan, J. L.; Cheng, Y.; Amos, R. T.; Steefel, C. I.; Ajo Franklin, J. B.

    2014-12-01

    Microbially mediated sulfate reduction is a ubiquitous process in many subsurface systems. Isotopic fractionation is characteristic of this anaerobic process, since sulfate reducing bacteria (SRB) favor the reduction of the lighter sulfate isotopologue (S32O42-) over the heavier isotopologue (S34O42-). Detection of isotopic shifts have been utilized as a proxy for the onset of sulfate reduction in subsurface systems such as oil reservoirs and aquifers undergoing uranium bioremediation. Reactive transport modeling (RTM) of kinetic sulfur isotope fractionation has been applied to field and laboratory studies. These RTM approaches employ different mathematical formulations in the representation of kinetic sulfur isotope fractionation. In order to test the various formulations, we propose a benchmark problem set for the simulation of kinetic sulfur isotope fractionation during microbially mediated sulfate reduction. The benchmark problem set is comprised of four problem levels and is based on a recent laboratory column experimental study of sulfur isotope fractionation. Pertinent processes impacting sulfur isotopic composition such as microbial sulfate reduction and dispersion are included in the problem set. To date, participating RTM codes are: CRUNCHTOPE, TOUGHREACT, MIN3P and THE GEOCHEMIST'S WORKBENCH. Preliminary results from various codes show reasonable agreement for the problem levels simulating sulfur isotope fractionation in 1D.

  1. Microworlds, Simulators, and Simulation: Framework for a Benchmark of Human Reliability Data Sources

    Energy Technology Data Exchange (ETDEWEB)

    Ronald Boring; Dana Kelly; Carol Smidts; Ali Mosleh; Brian Dyre

    2012-06-01

    In this paper, we propose a method to improve the data basis of human reliability analysis (HRA) by extending the data sources used to inform HRA methods. Currently, most HRA methods are based on limited empirical data, and efforts to enhance the empirical basis behind HRA methods have not yet yielded significant new data. Part of the reason behind this shortage of quality data is attributable to the data sources used. Data have been derived from unrelated industries, from infrequent risk-significant events, or from costly control room simulator studies. We propose a benchmark of four data sources: a simplified microworld simulator using unskilled student operators, a full-scope control room simulator using skilled student operators, a full-scope control room simulator using licensed commercial operators, and a human performance modeling and simulation system using virtual operators. The goal of this research is to compare findings across the data sources to determine to what extent data may be used and generalized from cost effective sources.

  2. Comparative testing of DNA segmentation algorithms using benchmark simulations.

    Science.gov (United States)

    Elhaik, Eran; Graur, Dan; Josic, Kresimir

    2010-05-01

    Numerous segmentation methods for the detection of compositionally homogeneous domains within genomic sequences have been proposed. Unfortunately, these methods yield inconsistent results. Here, we present a benchmark consisting of two sets of simulated genomic sequences for testing the performances of segmentation algorithms. Sequences in the first set are composed of fixed-sized homogeneous domains, distinct in their between-domain guanine and cytosine (GC) content variability. The sequences in the second set are composed of a mosaic of many short domains and a few long ones, distinguished by sharp GC content boundaries between neighboring domains. We use these sets to test the performance of seven segmentation algorithms in the literature. Our results show that recursive segmentation algorithms based on the Jensen-Shannon divergence outperform all other algorithms. However, even these algorithms perform poorly in certain instances because of the arbitrary choice of a segmentation-stopping criterion.

  3. Development of interfacial area transport equation - modeling and experimental benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, M. [Purdue Univ., West Lafayette, Indiana (United States)

    2011-07-01

    A dynamic treatment of interfacial area concentration has been studied over the last decade by employing the interfacial area transport equation. When coupled with the two-fluid model, the interfacial area transport equation replaces the flow regime dependent correlations for interfacial area concentration and eliminates potential artificial bifurcation or numerical oscillations stemming from these static correlations. An extensive database has been established to evaluate the model under various two-phase flow conditions. These include adiabatic and heated conditions, vertical and horizontal flow orientations, round, rectangular, annulus and 8×8 rod bundle channel geometries, and normal-gravity and simulated reduced-gravity conditions. This paper reviews the current state-of-the-art in the development of the interfacial area transport equation, available experimental databases and 1D and 3D benchmarking work of the interfacial area transport equation. (author)

  4. A simulation benchmark to evaluate the performance of advanced control techniques in biological wastewater treatment plants

    Directory of Open Access Journals (Sweden)

    Sotomayor O.A.Z.

    2001-01-01

    Full Text Available Wastewater treatment plants (WWTP are complex systems that incorporate a large number of biological, physicochemical and biochemical processes. They are large and nonlinear systems subject to great disturbances in incoming loads. The primary goal of a WWTP is to reduce pollutants and the second goal is disturbance rejection, in order to obtain good effluent quality. Modeling and computer simulations are key tools in the achievement of these two goals. They are essential to describe, predict and control the complicated interactions of the processes. Numerous control techniques (algorithms and control strategies (structures have been suggested to regulate WWTP; however, it is difficult to make a discerning performance evaluation due to the nonuniformity of the simulated plants used. The main objective of this paper is to present a benchmark of an entire biological wastewater treatment plant in order to evaluate, through simulations, different control techniques. This benchmark plays the role of an activated sludge process used for removal of organic matter and nitrogen from domestic effluents. The development of this simulator is based on models widely accepted by the international community and is implemented in Matlab/Simulink (The MathWorks, Inc. platform. The benchmark considers plant layout and the effects of influent characteristics. It also includes a test protocol for analyzing the open and closed-loop responses of the plant. Examples of control applications in the benchmark are implemented employing conventional PI controllers. The following common control strategies are tested: dissolved oxygen (DO concentration-based control, respirometry-based control and nitrate concentration-based control.

  5. IRIS-2012 OECD/NEA/CSNI benchmark: Numerical simulations of structural impact

    Energy Technology Data Exchange (ETDEWEB)

    Orbovic, Nebojsa, E-mail: nebojsa.orbovic@cnsc-ccsn.gc.ca [Canadian Nuclear Safety Commission, Ottawa, ON (Canada); Tarallo, Francois [IRSN, Fontenay aux Roses (France); Rambach, Jean-Mathieu [Géodynamique et Structures, Bagneux (France); Sagals, Genadijs; Blahoianu, Andrei [Canadian Nuclear Safety Commission, Ottawa, ON (Canada)

    2015-12-15

    A benchmark of numerical simulations related to the missile impact on reinforced concrete (RC) slabs has been launched in the frame of OECD/NEA/CSNI research program “Improving Robustness Assessment Methodologies for Structures Impacted by Missiles”, under the acronym IRIS. The goal of the research program is to simulate RC structural, flexural and punching, behavior under deformable and rigid missile impact. The first phase called IRIS-2010 was a blind prediction of the tests performed at VTT facility in Espoo, Finland. The two simulations were performed related to two series of tests: (1) two tests on the impact of a deformable missile exhibiting damage mainly by flexural (so-called “flexural tests”) or global response and (2) three tests on the impact of a rigid missile exhibiting damage mainly by punching response (so-called “punching tests”) or local response. The simulation results showed significant scatter (coefficient of variation up to 132%) for both flexural and punching cases. The IRIS-2012 is the second, post-test, phase of the benchmark with the goal to improve simulations and reduce the scatter of the results. Based on the IRIS-2010 recommendations and to better calibrate concrete constitutive models, a series of tri-axial tests as well as Brazilian tests were performed as a part of the IRIS-2012 benchmark. 25 teams from 11 countries took part in this exercise. Majority of participants were part of the IRIS-2010 benchmark. Participants showed significant improvement in reducing epistemic uncertainties in impact simulations. Several teams presented both finite element (FE) and simplified analysis as per recommendations of the IRIS-2010. The improvements were at the level of simulation results but also at the level of understanding of impact phenomena and its modeling. Due to the complexity of the physical phenomena and its simulation (high geometric and material non-linear behavior) and inherent epistemic and aleatory uncertainties, the

  6. Enthalpy benchmark experiments for numerical ice sheet models

    Directory of Open Access Journals (Sweden)

    T. Kleiner

    2014-06-01

    Full Text Available We present benchmark experiments to test the implementation of enthalpy and the corresponding boundary conditions in numerical ice sheet models. The first experiment tests particularly the functionality of the boundary condition scheme and the basal melt rate calculation during transient simulations. The second experiment addresses the steady-state enthalpy profile and the resulting position of the cold–temperate transition surface (CTS. For both experiments we assume ice flow in a parallel-sided slab decoupled from the thermal regime. Since we impose several assumptions on the experiment design, analytical solutions can be formulated for the proposed numerical experiments. We compare simulation results achieved by three different ice flow-models with these analytical solutions. The models agree well to the analytical solutions, if the change in conductivity between cold and temperate ice is properly considered in the model. In particular, the enthalpy gradient at the cold side of the CTS vanishes in the limit of vanishing conductivity in the temperate ice part as required from the physical jump conditions at the CTS.

  7. Performance benchmarks for a next generation numerical dynamo model

    Science.gov (United States)

    Matsui, Hiroaki; Heien, Eric; Aubert, Julien; Aurnou, Jonathan M.; Avery, Margaret; Brown, Ben; Buffett, Bruce A.; Busse, Friedrich; Christensen, Ulrich R.; Davies, Christopher J.; Featherstone, Nicholas; Gastine, Thomas; Glatzmaier, Gary A.; Gubbins, David; Guermond, Jean-Luc; Hayashi, Yoshi-Yuki; Hollerbach, Rainer; Hwang, Lorraine J.; Jackson, Andrew; Jones, Chris A.; Jiang, Weiyuan; Kellogg, Louise H.; Kuang, Weijia; Landeau, Maylis; Marti, Philippe; Olson, Peter; Ribeiro, Adolfo; Sasaki, Youhei; Schaeffer, Nathanaël.; Simitev, Radostin D.; Sheyko, Andrey; Silva, Luis; Stanley, Sabine; Takahashi, Futoshi; Takehiro, Shin-ichi; Wicht, Johannes; Willis, Ashley P.

    2016-05-01

    Numerical simulations of the geodynamo have successfully represented many observable characteristics of the geomagnetic field, yielding insight into the fundamental processes that generate magnetic fields in the Earth's core. Because of limited spatial resolution, however, the diffusivities in numerical dynamo models are much larger than those in the Earth's core, and consequently, questions remain about how realistic these models are. The typical strategy used to address this issue has been to continue to increase the resolution of these quasi-laminar models with increasing computational resources, thus pushing them toward more realistic parameter regimes. We assess which methods are most promising for the next generation of supercomputers, which will offer access to O(106) processor cores for large problems. Here we report performance and accuracy benchmarks from 15 dynamo codes that employ a range of numerical and parallelization methods. Computational performance is assessed on the basis of weak and strong scaling behavior up to 16,384 processor cores. Extrapolations of our weak-scaling results indicate that dynamo codes that employ two-dimensional or three-dimensional domain decompositions can perform efficiently on up to ˜106 processor cores, paving the way for more realistic simulations in the next model generation.

  8. Benchmarking Further Single Board Computers for Building a Mini Supercomputer for Simulation of Telecommunication Systems

    Directory of Open Access Journals (Sweden)

    Gábor Lencse

    2016-01-01

    Full Text Available Parallel Discrete Event Simulation (PDES with the conservative synchronization method can be efficiently used for the performance analysis of telecommunication systems because of their good lookahead properties. For PDES, a cost effective execution platform may be built by using single board computers (SBCs, which offer relatively high computation capacity compared to their price or power consumption and especially to the space they take up. A benchmarking method is proposed and its operation is demonstrated by benchmarking ten different SBCs, namely Banana Pi, Beaglebone Black, Cubieboard2, Odroid-C1+, Odroid-U3+, Odroid-XU3 Lite, Orange Pi Plus, Radxa Rock Lite, Raspberry Pi Model B+, and Raspberry Pi 2 Model B+. Their benchmarking results are compared to find out which one should be used for building a mini supercomputer for parallel discrete-event simulation of telecommunication systems. The SBCs are also used to build a heterogeneous cluster and the performance of the cluster is tested, too.

  9. Benchmarking numerical models of brittle thrust wedges

    Science.gov (United States)

    Buiter, Susanne J. H.; Schreurs, Guido; Albertz, Markus; Gerya, Taras V.; Kaus, Boris; Landry, Walter; le Pourhiet, Laetitia; Mishin, Yury; Egholm, David L.; Cooke, Michele; Maillot, Bertrand; Thieulot, Cedric; Crook, Tony; May, Dave; Souloumiac, Pauline; Beaumont, Christopher

    2016-11-01

    We report quantitative results from three brittle thrust wedge experiments, comparing numerical results directly with each other and with corresponding analogue results. We first test whether the participating codes reproduce predictions from analytical critical taper theory. Eleven codes pass the stable wedge test, showing negligible internal deformation and maintaining the initial surface slope upon horizontal translation over a frictional interface. Eight codes participated in the unstable wedge test that examines the evolution of a wedge by thrust formation from a subcritical state to the critical taper geometry. The critical taper is recovered, but the models show two deformation modes characterised by either mainly forward dipping thrusts or a series of thrust pop-ups. We speculate that the two modes are caused by differences in effective basal boundary friction related to different algorithms for modelling boundary friction. The third experiment examines stacking of forward thrusts that are translated upward along a backward thrust. The results of the seven codes that run this experiment show variability in deformation style, number of thrusts, thrust dip angles and surface slope. Overall, our experiments show that numerical models run with different numerical techniques can successfully simulate laboratory brittle thrust wedge models at the cm-scale. In more detail, however, we find that it is challenging to reproduce sandbox-type setups numerically, because of frictional boundary conditions and velocity discontinuities. We recommend that future numerical-analogue comparisons use simple boundary conditions and that the numerical Earth Science community defines a plasticity test to resolve the variability in model shear zones.

  10. Numerical simulations of concrete flow: A benchmark comparison

    DEFF Research Database (Denmark)

    Roussel, Nicolas; Gram, Annika; Cremonesi, Massimiliano;

    2016-01-01

    First, we define in this paper two benchmark flows readily usable by anyone calibrating a numerical tool for concrete flow prediction. Such benchmark flows shall allow anyone to check the validity of their computational tools no matter the numerical methods and parameters they choose. Second, we...... compare numerical predictions of the concrete sample final shape for these two benchmark flows obtained by various research teams around the world using various numerical techniques. Our results show that all numerical techniques compared here give very similar results suggesting that numerical...

  11. Benchmarking spin-state chemistry in starless core models

    CERN Document Server

    Sipilä, O; Harju, J

    2015-01-01

    Aims. We aim to present simulated chemical abundance profiles for a variety of important species, with special attention given to spin-state chemistry, in order to provide reference results against which present and future models can be compared. Methods. We employ gas-phase and gas-grain models to investigate chemical abundances in physical conditions corresponding to starless cores. To this end, we have developed new chemical reaction sets for both gas-phase and grain-surface chemistry, including the deuterated forms of species with up to six atoms and the spin-state chemistry of light ions and of the species involved in the ammonia and water formation networks. The physical model is kept simple in order to facilitate straightforward benchmarking of other models against the results of this paper. Results. We find that the ortho/para ratios of ammonia and water are similar in both gas-phase and gas-grain models, at late times in particular, implying that the ratios are determined by gas-phase processes. We d...

  12. Proxy benchmarks for intercomparison of 8.2 ka simulations

    Directory of Open Access Journals (Sweden)

    C. Morrill

    2012-08-01

    Full Text Available The Paleoclimate Modelling Intercomparison Project (PMIP3 now includes the 8.2 ka event as a test of model sensitivity to North Atlantic freshwater forcing. To provide benchmarks for intercomparison, we compiled and analyzed high-resolution records spanning this event. Two previously-described anomaly patterns that emerge are cooling around the North Atlantic and drier conditions in the Northern Hemisphere tropics. Newer to this compilation are more robustly-defined wetter conditions in the Southern Hemisphere tropics and regionally-limited warming in the Southern Hemisphere. Most anomalies around the globe lasted on the order of 100 to 150 yr. More quantitative reconstructions are now available and indicate cooling of 1.0 to 1.2 °C and a ~20% decrease in precipitation in parts of Europe, as well as spatial gradients in δ18O from the high to low latitudes. Unresolved questions remain about the seasonality of the climate response to freshwater forcing and the extent to which the bipolar seesaw operated in the early Holocene.

  13. Benchmarking a Visual-Basic based multi-component one-dimensional reactive transport modeling tool

    Science.gov (United States)

    Torlapati, Jagadish; Prabhakar Clement, T.

    2013-01-01

    We present the details of a comprehensive numerical modeling tool, RT1D, which can be used for simulating biochemical and geochemical reactive transport problems. The code can be run within the standard Microsoft EXCEL Visual Basic platform, and it does not require any additional software tools. The code can be easily adapted by others for simulating different types of laboratory-scale reactive transport experiments. We illustrate the capabilities of the tool by solving five benchmark problems with varying levels of reaction complexity. These literature-derived benchmarks are used to highlight the versatility of the code for solving a variety of practical reactive transport problems. The benchmarks are described in detail to provide a comprehensive database, which can be used by model developers to test other numerical codes. The VBA code presented in the study is a practical tool that can be used by laboratory researchers for analyzing both batch and column datasets within an EXCEL platform.

  14. Benchmark Study of 3D Pore-scale Flow and Solute Transport Simulation Methods

    Science.gov (United States)

    Scheibe, T. D.; Yang, X.; Mehmani, Y.; Perkins, W. A.; Pasquali, A.; Schoenherr, M.; Kim, K.; Perego, M.; Parks, M. L.; Trask, N.; Balhoff, M.; Richmond, M. C.; Geier, M.; Krafczyk, M.; Luo, L. S.; Tartakovsky, A. M.

    2015-12-01

    Multiple numerical approaches have been developed to simulate porous media fluid flow and solute transport at the pore scale. These include 1) methods that explicitly model the three-dimensional geometry of pore spaces and 2) methods that conceptualize the pore space as a topologically consistent set of stylized pore bodies and pore throats. In previous work we validated a model of the first type, using computational fluid dynamics (CFD) codes employing standard finite volume method (FVM), against magnetic resonance velocimetry (MRV) measurements of pore-scale velocities. Here we expand that benchmark study to include additional models of the first type based on the immersed-boundary method (IMB), lattice Boltzmann method (LBM), and smoothed particle hydrodynamics (SPH), as well as a model of the second type, a pore-network model (PNM). While the PNM approach is computationally much less demanding than direct numerical simulation methods, the effect of conceptualizing complex three-dimensional pore geometries in the manner of PNMs has not been fully determined. We apply all five approaches (FVM-based CFD, IMB, LBM, SPH and PNM) to simulate pore-scale velocity distributions and nonreactive solute transport, and intercompare the model results. Comparisons are drawn both in terms of macroscopic variables (e.g., permeability, solute breakthrough curves) and microscopic variables (e.g., local velocities and concentrations). Generally good agreement was achieved among the various approaches, but some differences were observed depending on the model context. The benchmark study was challenging because of variable capabilities of the codes, and inspired some code enhancements to allow consistent comparison of flow and transport simulations across the full suite of methods. This study provides support for confidence in a variety of pore-scale modeling methods, and motivates further development and application of pore-scale simulation methods.

  15. TCSC impedance regulator applied to the second benchmark model

    Energy Technology Data Exchange (ETDEWEB)

    Hamel, J.P.; Dessaint, L.A. [Ecole de Technologie Superieure, Montreal, PQ (Canada). Dept. of Electrical Engineering; Champagne, R. [Ecole de Technologie Superieure, Montreal, PQ (Canada). Dept. of Software and IT Engineering; Pare, D. [Institut de Recherche d' Hydro-Quebec, Varennes, PQ (Canada)

    2008-07-01

    Due to the combination of electrical demand growth and the high cost of building new power transmission lines, series compensation is increasingly used in power systems all around the world. Series compensation has been proposed as a new way to transfer more power on existing lines. By adding series compensation to an existing line (a relatively small change), the power transfer can be increased significantly. One of the means used for line compensation is the addition of capacitive elements in series with the line. This paper presented a thyristor-controlled series capacitor (TCSC) model that used impedance as reference, had individual controls for each phase, included a linearization module and considered only the fundamental frequency for impedance computations, without using any filter. The model's dynamic behavior was validated by applying it to the second benchmark model for subsynchronous resonance (SSR). Simulation results from the proposed model, obtained using EMTP-RV and SimPowerSystems were demonstrated. It was concluded that SSR was mitigated by the proposed approach. 19 refs., 19 figs.

  16. Evaluation of the Aleph PIC Code on Benchmark Simulations

    Science.gov (United States)

    Boerner, Jeremiah; Pacheco, Jose; Grillet, Anne

    2016-09-01

    Aleph is a massively parallel, 3D unstructured mesh, Particle-in-Cell (PIC) code, developed to model low temperature plasma applications. In order to verify and validate performance, Aleph is benchmarked against a series of canonical problems to demonstrate statistical indistinguishability in the results. Here, a series of four problems is studied: Couette flows over a range of Knudsen number, sheath formation in an undriven plasma, the two-stream instability, and a capacitive discharge. These problems respectively exercise collisional processes, particle motion in electrostatic fields, electrostatic field solves coupled to particle motion, and a fully coupled reacting plasma. Favorable comparison with accepted results establishes confidence in Aleph's capability and accuracy as a general purpose PIC code. Finally, Aleph is used to investigate the sensitivity of a triggered vacuum gap switch to the particle injection conditions associated with arc breakdown at the trigger. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  17. Benchmark of Schemes for Multiscale Molecular Dynamics Simulations

    NARCIS (Netherlands)

    Goga, N.; Melo, M. N.; Rzepiela, A. J.; de Vries, Alex; Hadar, A.; Marrink, S. J.; Berendsen, Herman

    2015-01-01

    In multiscale molecular dynamics simulations the accuracy of detailed models is combined with the efficiency of a reduced representation. For several applications - namely those of sampling enhancement - it is desirable to combine fine-grained (FG) and coarse-grained (CG) approaches into a single hy

  18. Fundamental modeling issues on benchmark structure for structural health monitoring

    Institute of Scientific and Technical Information of China (English)

    LI HuaJun; ZHANG Min; WANG JunRong; HU Sau-Lon James

    2009-01-01

    The IASC-ASCE Structural Health Monitoring Task Group developed a series of benchmark problems,and participants of the benchmark study were charged with using a 12-degree-of-freedom (DOF) shear building as their identification model. The present article addresses improperness, including the parameter and modeling errors, of using this particular model for the intended purpose of damage detection, while the measurements of damaged structures are synthesized from a full-order finite-element model. In addressing parameter errors, a model calibration procedure is utilized to tune the mass and stiffness matrices of the baseline identification model, and a 12-DOF shear building model that preserves the first three modes of the full-order model is obtained. Sequentially, this calibrated model is employed as the baseline model while performing the damage detection under various damage scenarios. Numerical results indicate that the 12-DOF shear building model is an over-simplified identification model, through which only idealized damage situations for the benchmark structure can be detected. It is suggested that a more sophisticated 3-dimensional frame structure model should be adopted as the identification model, if one intends to detect local member damages correctly.

  19. Fundamental modeling issues on benchmark structure for structural health monitoring

    Institute of Scientific and Technical Information of China (English)

    HU; Sau-Lon; James

    2009-01-01

    The IASC-ASCE Structural Health Monitoring Task Group developed a series of benchmark problems, and participants of the benchmark study were charged with using a 12-degree-of-freedom (DOF) shear building as their identification model. The present article addresses improperness, including the parameter and modeling errors, of using this particular model for the intended purpose of damage detec- tion, while the measurements of damaged structures are synthesized from a full-order finite-element model. In addressing parameter errors, a model calibration procedure is utilized to tune the mass and stiffness matrices of the baseline identification model, and a 12-DOF shear building model that preserves the first three modes of the full-order model is obtained. Sequentially, this calibrated model is employed as the baseline model while performing the damage detection under various damage scenarios. Numerical results indicate that the 12-DOF shear building model is an over-simplified identification model, through which only idealized damage situations for the benchmark structure can be detected. It is suggested that a more sophisticated 3-dimensional frame structure model should be adopted as the identification model, if one intends to detect local member damages correctly.

  20. Numerical simulations of missile impacts on reinforced concrete plates: IRIS-2010/2012 benchmark project

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Chulhun, E-mail: chchung5@dankook.ac.kr [Department of Civil and Environmental Engineering, Dankook University, 126 Jukjeon-dong, Yongin-si 448-701 (Korea, Republic of); Lee, Jungwhee, E-mail: jwhee2@dankook.ac.kr [Department of Civil and Environmental Engineering, Dankook University, 126 Jukjeon-dong, Yongin-si 448-701 (Korea, Republic of); Jung, Raeyoung, E-mail: k701jry@kins.re.kr [Korea Institute of Nuclear Safety, 62 Gwahak-ro, Yuseong-gu, Daejeon 305-600 (Korea, Republic of)

    2015-12-15

    Highlights: • The procedures and results performed during the IRIS-2010/2012 projects are described. • Numerical impact simulations were performed and the initial FE model was updated. • Loading function with a fictitious loading plate approach was suggested. • Three concrete models were used and the results were compared. - Abstract: This paper describes the procedures and results of the works done by the Korea Institute of Nuclear Safety (KINS) as a participant of the IRIS-2010 and 2012 benchmark projects, which have been organized by OECD/NEA IAGE working group. Within the scope of the IRIS-2012 project, uniaxial and tri-axial concrete tests were performed and the results were supplied. With these material test data, impact simulations of IRIS-2010 experiments (Punching P1 and Bending B1) were re-performed to improve the accuracy of the simulation results and to reduce the computation time. Numerical impact simulations were performed using an explicit dynamic code, LS-DYNA, and the initial FE model was updated through numerous parametric studies. Considering the symmetry of the structure, an updated model was constructed for ¼ of the structure, and the stiffness and mass of the supporting structure was considered. Loading function with a fictitious loading plate was applied instead of modeling projectiles to reduce the computation time. Three concrete models, Concrete damage rel. 3 (*MAT-072R3), Winfrith concrete (*MAT-084-085), and CSCM concrete (*MAT-159), were used for the impact simulations and the results were compared.

  1. Results of the 2013 UT modeling benchmark obtained with models implemented in CIVA

    Energy Technology Data Exchange (ETDEWEB)

    Toullelan, Gwénaël; Raillon, Raphaële; Chatillon, Sylvain [CEA, LIST, 91191Gif-sur-Yvette (France); Lonne, Sébastien [EXTENDE, Le Bergson, 15 Avenue Emile Baudot, 91300 MASSY (France)

    2014-02-18

    The 2013 Ultrasonic Testing (UT) modeling benchmark concerns direct echoes from side drilled holes (SDH), flat bottom holes (FBH) and corner echoes from backwall breaking artificial notches inspected with a matrix phased array probe. This communication presents the results obtained with the models implemented in the CIVA software: the pencilmodel is used to compute the field radiated by the probe, the Kirchhoff approximation is applied to predict the response of FBH and notches and the SOV (Separation Of Variables) model is used for the SDH responses. The comparison between simulated and experimental results are presented and discussed.

  2. Parareal in time 3D numerical solver for the LWR Benchmark neutron diffusion transient model

    CERN Document Server

    Baudron, Anne-Marie A -M; Maday, Yvon; Riahi, Mohamed Kamel; Salomon, Julien

    2014-01-01

    We present a parareal in time algorithm for the simulation of neutron diffusion transient model. The method is made efficient by means of a coarse solver defined with large time steps and steady control rods model. Using finite element for the space discretization, our implementation provides a good scalability of the algorithm. Numerical results show the efficiency of the parareal method on large light water reactor transient model corresponding to the Langenbuch-Maurer-Werner (LMW) benchmark [1].

  3. Large eddy simulation of the FDA benchmark nozzle for a Reynolds number of 6500.

    Science.gov (United States)

    Janiga, Gábor

    2014-04-01

    This work investigates the flow in a benchmark nozzle model of an idealized medical device proposed by the FDA using computational fluid dynamics (CFD). It was in particular shown that a proper modeling of the transitional flow features is particularly challenging, leading to large discrepancies and inaccurate predictions from the different research groups using Reynolds-averaged Navier-Stokes (RANS) modeling. In spite of the relatively simple, axisymmetric computational geometry, the resulting turbulent flow is fairly complex and non-axisymmetric, in particular due to the sudden expansion. The resulting flow cannot be well predicted with simple modeling approaches. Due to the varying diameters and flow velocities encountered in the nozzle, different typical flow regions and regimes can be distinguished, from laminar to transitional and to weakly turbulent. The purpose of the present work is to re-examine the FDA-CFD benchmark nozzle model at a Reynolds number of 6500 using large eddy simulation (LES). The LES results are compared with published experimental data obtained by Particle Image Velocimetry (PIV) and an excellent agreement can be observed considering the temporally averaged flow velocities. Different flow regimes are characterized by computing the temporal energy spectra at different locations along the main axis.

  4. Benchmarking of Advanced Control Strategies for a Simulated Hydroelectric System

    Science.gov (United States)

    Finotti, S.; Simani, S.; Alvisi, S.; Venturini, M.

    2017-01-01

    This paper analyses and develops the design of advanced control strategies for a typical hydroelectric plant during unsteady conditions, performed in the Matlab and Simulink environments. The hydraulic system consists of a high water head and a long penstock with upstream and downstream surge tanks, and is equipped with a Francis turbine. The nonlinear characteristics of hydraulic turbine and the inelastic water hammer effects were considered to calculate and simulate the hydraulic transients. With reference to the control solutions addressed in this work, the proposed methodologies rely on data-driven and model-based approaches applied to the system under monitoring. Extensive simulations and comparisons serve to determine the best solution for the development of the most effective, robust and reliable control tool when applied to the considered hydraulic system.

  5. Implementing ADM1 for plant-wide benchmark simulations in Matlab/Simulink.

    Science.gov (United States)

    Rosen, C; Vrecko, D; Gernaey, K V; Pons, M N; Jeppsson, U

    2006-01-01

    The IWA Anaerobic Digestion Model No.1 (ADM1) was presented in 2002 and is expected to represent the state-of-the-art model within this field in the future. Due to its complexity the implementation of the model is not a simple task and several computational aspects need to be considered, in particular if the ADM1 is to be included in dynamic simulations of plant-wide or even integrated systems. In this paper, the experiences gained from a Matlab/Simulink implementation of ADM1 into the extended COST/IWA Benchmark Simulation Model (BSM2) are presented. Aspects related to system stiffness, model interfacing with the ASM family, mass balances, acid-base equilibrium and algebraic solvers for pH and other troublesome state variables, numerical solvers and simulation time are discussed. The main conclusion is that if implemented properly, the ADM1 will also produce high-quality results in dynamic plant-wide simulations including noise, discrete sub-systems, etc. without imposing any major restrictions due to extensive computational efforts.

  6. Benchmarking of measurement and simulation of transverse rms-emittance growth

    Science.gov (United States)

    Groening, L.; Barth, W.; Bayer, W.; Clemente, G.; Dahl, L.; Forck, P.; Gerhard, P.; Hofmann, I.; Riehl, G.; Yaramyshev, S.; Jeon, D.; Uriot, D.

    2008-09-01

    Transverse emittance growth along the Alvarez drift tube linac (DTL) section is a major concern with respect to the preservation of beam quality of high current beams at the GSI UNILAC. In order to define measures to reduce this growth, appropriate tools to simulate the beam dynamics are indispensable. This paper is about the benchmarking of three beam dynamics simulation codes, i.e. DYNAMION, PARMILA, and PARTRAN against systematic measurements of beam emittances for different transverse phase advances along the DTL. Special emphasis is put on the modeling of the initial distribution for the simulations. The concept of rms equivalence is expanded from full intensity to fractions of less than 100% of the beam. The experimental setup, data reduction, preparation of the simulations, and the evaluation of the simulations are described. In the experiments and in the simulations, a minimum of the rms-emittance growth was observed at zero current phase advances of about 60°. In general, good agreement was found between simulations and experiment for the mean values of horizontal and vertical emittances at the DTL exit.

  7. Simulation of thermos-solutal convection induced macrosegregation in a Sn-10%Pb alloy benchmark during columnar solidification

    Science.gov (United States)

    Zheng, Y.; Wu, M.; Kharicha, A.; Ludwig, A.

    2016-03-01

    In order to investigate the effect of thermo-solutal convection on the formation of macrosegregation during columnar solidification, simulations with a liquid-columnar two phase model were carried out on a 2D rectangular benchmark of Sn-10%Pb alloy. The solidification direction in the benchmark is unidirectional: (') downwards from top to bottom or (2) upwards from bottom to top. Thermal expansion coefficient, solutal expansion coefficient and liquid diffusion coefficient of the melt are found to be key factors influencing the final macrosegregation. The segregation range and distribution are also strongly influenced by the benchmark configurations, e.g. the solidifying direction (upwards or downwards) and boundary conditions, et al. The global macrosegregation range increases with the velocity magnitude of the melt during the process of solidification.

  8. Theoretical benchmarking of laser-accelerated ion fluxes by 2D-PIC simulations

    CERN Document Server

    Mackenroth, Felix; Marklund, Mattias

    2016-01-01

    There currently exists a number of different schemes for laser based ion acceleration in the literature. Some of these schemes are also partly overlapping, making a clear distinction between the schemes difficult in certain parameter regimes. Here, we provide a systematic numerical comparison between the following schemes and their analytical models: light-sail acceleration, Coulomb explosions, hole boring acceleration, and target normal sheath acceleration (TNSA). We study realistic laser parameters and various different target designs, each optimized for one of the acceleration schemes, respectively. As a means of comparing the schemes, we compute the ion current density generated at different laser powers, using two-dimensional particle-in-cell (PIC) simulations, and benchmark the particular analytical models for the corresponding schemes against the numerical results. Finally, we discuss the consequences for attaining high fluxes through the studied laser ion-acceleration schemes.

  9. Project W-320 thermal hydraulic model benchmarking and baselining

    Energy Technology Data Exchange (ETDEWEB)

    Sathyanarayana, K.

    1998-09-28

    Project W-320 will be retrieving waste from Tank 241-C-106 and transferring the waste to Tank 241-AY-102. Waste in both tanks must be maintained below applicable thermal limits during and following the waste transfer. Thermal hydraulic process control models will be used for process control of the thermal limits. This report documents the process control models and presents a benchmarking of the models with data from Tanks 241-C-106 and 241-AY-102. Revision 1 of this report will provide a baselining of the models in preparation for the initiation of sluicing.

  10. RESRAD benchmarking against six radiation exposure pathway models

    Energy Technology Data Exchange (ETDEWEB)

    Faillace, E.R.; Cheng, J.J.; Yu, C.

    1994-10-01

    A series of benchmarking runs were conducted so that results obtained with the RESRAD code could be compared against those obtained with six pathway analysis models used to determine the radiation dose to an individual living on a radiologically contaminated site. The RESRAD computer code was benchmarked against five other computer codes - GENII-S, GENII, DECOM, PRESTO-EPA-CPG, and PATHRAE-EPA - and the uncodified methodology presented in the NUREG/CR-5512 report. Estimated doses for the external gamma pathway; the dust inhalation pathway; and the soil, food, and water ingestion pathways were calculated for each methodology by matching, to the extent possible, input parameters such as occupancy, shielding, and consumption factors.

  11. Physical properties of the benchmark models program supercritical wing

    Science.gov (United States)

    Dansberry, Bryan E.; Durham, Michael H.; Bennett, Robert M.; Turnock, David L.; Silva, Walter A.; Rivera, Jose A., Jr.

    1993-01-01

    The goal of the Benchmark Models Program is to provide data useful in the development and evaluation of aeroelastic computational fluid dynamics (CFD) codes. To that end, a series of three similar wing models are being flutter tested in the Langley Transonic Dynamics Tunnel. These models are designed to simultaneously acquire model response data and unsteady surface pressure data during wing flutter conditions. The supercritical wing is the second model of this series. It is a rigid semispan model with a rectangular planform and a NASA SC(2)-0414 supercritical airfoil shape. The supercritical wing model was flutter tested on a flexible mount, called the Pitch and Plunge Apparatus, that provides a well-defined, two-degree-of-freedom dynamic system. The supercritical wing model and associated flutter test apparatus is described and experimentally determined wind-off structural dynamic characteristics of the combined rigid model and flexible mount system are included.

  12. Experimental verification of boundary conditions for numerical simulation of airflow in a benchmark ventilation channel

    Directory of Open Access Journals (Sweden)

    Lizal Frantisek

    2016-01-01

    Full Text Available Correct definition of boundary conditions is crucial for the appropriate simulation of a flow. It is a common practice that simulation of sufficiently long upstream entrance section is performed instead of experimental investigation of the actual conditions at the boundary of the examined area, in the case that the measurement is either impossible or extremely demanding. We focused on the case of a benchmark channel with ventilation outlet, which models a regular automotive ventilation system. At first, measurements of air velocity and turbulence intensity were performed at the boundary of the examined area, i.e. in the rectangular channel 272.5 mm upstream the ventilation outlet. Then, the experimentally acquired results were compared with results obtained by numerical simulation of further upstream entrance section defined according to generally approved theoretical suggestions. The comparison showed that despite the simple geometry and general agreement of average axial velocity, certain difference was found in the shape of the velocity profile. The difference was attributed to the simplifications of the numerical model and the isotropic turbulence assumption of the used turbulence model. The appropriate recommendations were stated for the future work.

  13. Benchmarking an unstructured grid sediment model in an energetic estuary

    Science.gov (United States)

    Lopez, Jesse E.; Baptista, António M.

    2017-02-01

    A sediment model coupled to the hydrodynamic model SELFE is validated against a benchmark combining a set of idealized tests and an application to a field-data rich energetic estuary. After sensitivity studies, model results for the idealized tests largely agree with previously reported results from other models in addition to analytical, semi-analytical, or laboratory results. Results of suspended sediment in an open channel test with fixed bottom are sensitive to turbulence closure and treatment for hydrodynamic bottom boundary. Results for the migration of a trench are very sensitive to critical stress and erosion rate, but largely insensitive to turbulence closure. The model is able to qualitatively represent sediment dynamics associated with estuarine turbidity maxima in an idealized estuary. Applied to the Columbia River estuary, the model qualitatively captures sediment dynamics observed by fixed stations and shipborne profiles. Representation of the vertical structure of suspended sediment degrades when stratification is underpredicted. Across all tests, skill metrics of suspended sediments lag those of hydrodynamics even when qualitatively representing dynamics. The benchmark is fully documented in an openly available repository to encourage unambiguous comparisons against other models.

  14. Verification and validation benchmarks.

    Energy Technology Data Exchange (ETDEWEB)

    Oberkampf, William Louis; Trucano, Timothy Guy

    2007-02-01

    Verification and validation (V&V) are the primary means to assess the accuracy and reliability of computational simulations. V&V methods and procedures have fundamentally improved the credibility of simulations in several high-consequence fields, such as nuclear reactor safety, underground nuclear waste storage, and nuclear weapon safety. Although the terminology is not uniform across engineering disciplines, code verification deals with assessing the reliability of the software coding, and solution verification deals with assessing the numerical accuracy of the solution to a computational model. Validation addresses the physics modeling accuracy of a computational simulation by comparing the computational results with experimental data. Code verification benchmarks and validation benchmarks have been constructed for a number of years in every field of computational simulation. However, no comprehensive guidelines have been proposed for the construction and use of V&V benchmarks. For example, the field of nuclear reactor safety has not focused on code verification benchmarks, but it has placed great emphasis on developing validation benchmarks. Many of these validation benchmarks are closely related to the operations of actual reactors at near-safety-critical conditions, as opposed to being more fundamental-physics benchmarks. This paper presents recommendations for the effective design and use of code verification benchmarks based on manufactured solutions, classical analytical solutions, and highly accurate numerical solutions. In addition, this paper presents recommendations for the design and use of validation benchmarks, highlighting the careful design of building-block experiments, the estimation of experimental measurement uncertainty for both inputs and outputs to the code, validation metrics, and the role of model calibration in validation. It is argued that the understanding of predictive capability of a computational model is built on the level of

  15. Results of the 2014 UT modeling benchmark obtained with models implemented in CIVA: Solution of the FMC-TFM ultrasonic benchmark problem using CIVA

    Science.gov (United States)

    Chatillon, Sylvain; Robert, Sébastien; Brédif, Philippe; Calmon, Pierre; Daniel, Guillaume; Cartier, François

    2015-03-01

    The last decade has seen the emergence of new ultrasonic array techniques going beyond the simple application of suitable delays (phased array techniques) for focusing purposes. Amongst these techniques, the particular method combining the so-called FMC (Full Matrix Capture) acquisition scheme with the synthetic focusing algorithm denoted by TFM (Total Focusing Method) has become popular in the NDE community. The 2014 WFNDEC ultrasonic benchmark aims at providing FMC experimental data for evaluating the ability of models to predict images obtained by TFM algorithms (or equivalent ones). In this paper we describe the benchmark and report comparisons obtained with the CIVA simulation software. The simulations and measurements are carried out on two steel blocks, one in carbon steel and another in stainless steel. The reference probe is a 64 elements linear array, with .5mm element width and a gap of .1mm, working at 5 MHz. The benchmark problem consists in predicting images of vertical and tilted notches located on plane or inclined backwalls. The notches have different heights and different ligaments. The images can be obtained considering different paths (direct echoes or corner echoes). For each notch, the full matrix capture (FMC) have been recorded in one unique position with the probe positioned such that than angle between the probe axis and the notch direction corresponds to 45°. The results are calibrated on the response of a 2mm side drilled hole. For each case, TFM images have been reconstructed for both experimental and simulated signals. The models used are those implemented in CIVA based on Kirchhoff approximation. Comparisons are reported and discussed.

  16. Benchmarking analysis of three multimedia models: RESRAD, MMSOILS, and MEPAS

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, J.J.; Faillace, E.R.; Gnanapragasam, E.K. [and others

    1995-11-01

    Multimedia modelers from the United States Environmental Protection Agency (EPA) and the United States Department of Energy (DOE) collaborated to conduct a comprehensive and quantitative benchmarking analysis of three multimedia models. The three models-RESRAD (DOE), MMSOILS (EPA), and MEPAS (DOE)-represent analytically based tools that are used by the respective agencies for performing human exposure and health risk assessments. The study is performed by individuals who participate directly in the ongoing design, development, and application of the models. A list of physical/chemical/biological processes related to multimedia-based exposure and risk assessment is first presented as a basis for comparing the overall capabilities of RESRAD, MMSOILS, and MEPAS. Model design, formulation, and function are then examined by applying the models to a series of hypothetical problems. Major components of the models (e.g., atmospheric, surface water, groundwater) are evaluated separately and then studied as part of an integrated system for the assessment of a multimedia release scenario to determine effects due to linking components of the models. Seven modeling scenarios are used in the conduct of this benchmarking study: (1) direct biosphere exposure, (2) direct release to the air, (3) direct release to the vadose zone, (4) direct release to the saturated zone, (5) direct release to surface water, (6) surface water hydrology, and (7) multimedia release. Study results show that the models differ with respect to (1) environmental processes included (i.e., model features) and (2) the mathematical formulation and assumptions related to the implementation of solutions (i.e., parameterization).

  17. Information-Theoretic Benchmarking of Land Surface Models

    Science.gov (United States)

    Nearing, Grey; Mocko, David; Kumar, Sujay; Peters-Lidard, Christa; Xia, Youlong

    2016-04-01

    Benchmarking is a type of model evaluation that compares model performance against a baseline metric that is derived, typically, from a different existing model. Statistical benchmarking was used to qualitatively show that land surface models do not fully utilize information in boundary conditions [1] several years before Gong et al [2] discovered the particular type of benchmark that makes it possible to *quantify* the amount of information lost by an incorrect or imperfect model structure. This theoretical development laid the foundation for a formal theory of model benchmarking [3]. We here extend that theory to separate uncertainty contributions from the three major components of dynamical systems models [4]: model structures, model parameters, and boundary conditions describe time-dependent details of each prediction scenario. The key to this new development is the use of large-sample [5] data sets that span multiple soil types, climates, and biomes, which allows us to segregate uncertainty due to parameters from the two other sources. The benefit of this approach for uncertainty quantification and segregation is that it does not rely on Bayesian priors (although it is strictly coherent with Bayes' theorem and with probability theory), and therefore the partitioning of uncertainty into different components is *not* dependent on any a priori assumptions. We apply this methodology to assess the information use efficiency of the four land surface models that comprise the North American Land Data Assimilation System (Noah, Mosaic, SAC-SMA, and VIC). Specifically, we looked at the ability of these models to estimate soil moisture and latent heat fluxes. We found that in the case of soil moisture, about 25% of net information loss was from boundary conditions, around 45% was from model parameters, and 30-40% was from the model structures. In the case of latent heat flux, boundary conditions contributed about 50% of net uncertainty, and model structures contributed

  18. Benchmarking and scaling studies of pseudospectral code Tarang for turbulence simulations

    Indian Academy of Sciences (India)

    Mahendra K Verma; Anando Chatterjee; K Sandeep Reddy; Rakesh K Yadav; Supriyo Paul; Mani Chandra; Ravi Samtaney

    2013-10-01

    Tarang is a general-purpose pseudospectral parallel code for simulating flows involving fluids, magnetohydrodynamics, and Rayleigh–Bénard convection in turbulence and instability regimes. In this paper we present code validation and benchmarking results of Tarang. We performed our simulations on 10243, 20483, and 40963 grids using the HPC system of IIT Kanpur and Shaheen of KAUST. We observe good `weak' and `strong' scaling for Tarang on these systems.

  19. Benchmarking and scaling studies of pseudospectral code Tarang for turbulence simulations

    KAUST Repository

    VERMA, MAHENDRA K

    2013-09-21

    Tarang is a general-purpose pseudospectral parallel code for simulating flows involving fluids, magnetohydrodynamics, and Rayleigh–Bénard convection in turbulence and instability regimes. In this paper we present code validation and benchmarking results of Tarang. We performed our simulations on 10243, 20483, and 40963 grids using the HPC system of IIT Kanpur and Shaheen of KAUST. We observe good ‘weak’ and ‘strong’ scaling for Tarang on these systems.

  20. TCC-III Engine Benchmark for Large-Eddy Simulation of IC Engine Flows

    Directory of Open Access Journals (Sweden)

    Schiffmann P.

    2016-01-01

    Full Text Available A collaborative effort is described to benchmark the TCC-III engine, and to illustrate the application of this data for the evaluation of sub-grid scale models and valve simulation details on the fidelity of Large-Eddy Simulations (LES. The TCC-III is a spark ignition 4-stroke 2-valve engine with a flat head and piston and is equipped with a full quartz liner for maximum optical access that allows high-speed flow measurements with Particle Image Velocimetry (PIV; the TCC-III has new valve seats and a modified intake-system compared to previous configurations. This work is an extension of a previous study at an engine speed of 800 RPM and an intake manifold pressure (MAP of 95 kPa, where a one-equation eddy viscosity LES model yielded accurate qualitative and quantitative predictions of ensemble averaged mean and RMS velocities during the intake and compression stroke. Here, experimental data were acquired with parametric variation of engine speed and intake manifold absolute pressure to assess the capability of LES models over a range of operating conditions of practical relevance. This paper focuses on the repeatability and accuracy of the measured PIV data, acquired at 1 300 RPM, at two different MAP (95 kPa and 40 kPa, and imaged at multiple data planes and crank angles. Two examples are provided, illustrating the application of this data to LES model development. In one example, the experimental data are used to distinguish between the efficacies of a one-equation eddy viscosity model versus a dynamic structure one-equation model for the sub-grid stresses. The second example addresses the effects of numerical intake-valve opening strategy and local mesh refinement in the valve curtain.

  1. Beam equipment electromagnetic interaction in accelerators: simulation and experimental benchmarking

    CERN Document Server

    Passarelli, Andrea; Vaccaro, Vittorio Giorgio; Massa, Rita; Masullo, Maria Rosaria

    One of the most significant technological problems to achieve the nominal performances in the Large Hadron Collider (LHC) concerns the system of collimation of particle beams. The use of collimators crystals, exploiting the channeling effect on extracted beam, has been experimentally demonstrated. The first part of this thesis is about the optimization of UA9 goniometer at CERN, this device used for beam collimation will replace a part of the vacuum chamber. The optimization process, however, requires the calculation of the coupling impedance between the circulating beam and this structure in order to define the threshold of admissible intensity to do not trigger instability processes. Simulations have been performed with electromagnetic codes to evaluate the coupling impedance and to assess the beam-structure interaction. The results clearly showed that the most concerned resonance frequencies are due solely to the open cavity to the compartment of the motors and position sensors considering the crystal in o...

  2. CFD Simulation of Thermal-Hydraulic Benchmark V1000CT-2 Using ANSYS CFX

    Directory of Open Access Journals (Sweden)

    Thomas Höhne

    2009-01-01

    Full Text Available Plant measured data from VVER-1000 coolant mixing experiments were used within the OECD/NEA and AER coupled code benchmarks for light water reactors to test and validate computational fluid dynamic (CFD codes. The task is to compare the various calculations with measured data, using specified boundary conditions and core power distributions. The experiments, which are provided for CFD validation, include single loop cooling down or heating-up by disturbing the heat transfer in the steam generator through the steam valves at low reactor power and with all main coolant pumps in operation. CFD calculations have been performed using a numerical grid model of 4.7 million tetrahedral elements. The Best Practice Guidelines in using CFD in nuclear reactor safety applications has been used. Different advanced turbulence models were utilized in the numerical simulation. The results show a clear sector formation of the affected loop at the downcomer, lower plenum and core inlet, which corresponds to the measured values. The maximum local values of the relative temperature rise in the calculation are in the same range of the experiment. Due to this result, it is now possible to improve the mixing models which are usually used in system codes.

  3. Benchmarking consensus model quality assessment for protein fold recognition

    Directory of Open Access Journals (Sweden)

    McGuffin Liam J

    2007-09-01

    Full Text Available Abstract Background Selecting the highest quality 3D model of a protein structure from a number of alternatives remains an important challenge in the field of structural bioinformatics. Many Model Quality Assessment Programs (MQAPs have been developed which adopt various strategies in order to tackle this problem, ranging from the so called "true" MQAPs capable of producing a single energy score based on a single model, to methods which rely on structural comparisons of multiple models or additional information from meta-servers. However, it is clear that no current method can separate the highest accuracy models from the lowest consistently. In this paper, a number of the top performing MQAP methods are benchmarked in the context of the potential value that they add to protein fold recognition. Two novel methods are also described: ModSSEA, which based on the alignment of predicted secondary structure elements and ModFOLD which combines several true MQAP methods using an artificial neural network. Results The ModSSEA method is found to be an effective model quality assessment program for ranking multiple models from many servers, however further accuracy can be gained by using the consensus approach of ModFOLD. The ModFOLD method is shown to significantly outperform the true MQAPs tested and is competitive with methods which make use of clustering or additional information from multiple servers. Several of the true MQAPs are also shown to add value to most individual fold recognition servers by improving model selection, when applied as a post filter in order to re-rank models. Conclusion MQAPs should be benchmarked appropriately for the practical context in which they are intended to be used. Clustering based methods are the top performing MQAPs where many models are available from many servers; however, they often do not add value to individual fold recognition servers when limited models are available. Conversely, the true MQAP methods

  4. Benchmarking nuclear models for Gamow–Teller response

    Energy Technology Data Exchange (ETDEWEB)

    Litvinova, E., E-mail: elena.litvinova@wmich.edu [Department of Physics, Western Michigan University, Kalamazoo, MI 49008-5252 (United States); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321 (United States); Brown, B.A. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824-1321 (United States); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321 (United States); Fang, D.-L. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824-1321 (United States); Marketin, T. [Physics Department, Faculty of Science, University of Zagreb (Croatia); Zegers, R.G.T. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824-1321 (United States); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824-1321 (United States)

    2014-03-07

    A comparative study of the nuclear Gamow–Teller response (GTR) within conceptually different state-of-the-art approaches is presented. Three nuclear microscopic models are considered: (i) the recently developed charge-exchange relativistic time blocking approximation (RTBA) based on the covariant density functional theory, (ii) the shell model (SM) with an extended “jj77” model space and (iii) the non-relativistic quasiparticle random-phase approximation (QRPA) with a Brueckner G-matrix effective interaction. We study the physics cases where two or all three of these models can be applied. The Gamow–Teller response functions are calculated for {sup 208}Pb, {sup 132}Sn and {sup 78}Ni within both RTBA and QRPA. The strengths obtained for {sup 208}Pb are compared to data that enable a firm model benchmarking. For the nucleus {sup 132}Sn, also SM calculations are performed within the model space truncated at the level of a particle–hole (ph) coupled to vibration configurations. This allows a consistent comparison to the RTBA where ph⊗phonon coupling is responsible for the spreading width and considerable quenching of the GTR. Differences between the models and perspectives of their future developments are discussed.

  5. Dark Current and Multipacting Capabilities in OPAL: Model Benchmarks and Applications

    CERN Document Server

    Wang, C; Yin, Z G; Zhang, T J

    2012-01-01

    Dark current and multiple electron impacts (multipacting), as for example observed in radio frequency (RF) structures of accelerators, are usually harmful to the equipment and the beam quality. These effects need to be suppressed to guarantee efficient and stable operation. Large scale simulations can be used to understand causes and develop strategies to suppress these phenomenas. We extend \\opal, a parallel framework for charged particle optics in accelerator structures and beam lines, with the necessary physics models to efficiently and precisely simulate multipacting phenomenas. We added a Fowler-Nordheim field emission model, two secondary electron emission models, developed by Furman-Pivi and Vaughan respectively, as well as efficient 3D boundary geometry handling capabilities. The models and their implementation are carefully benchmark against a non-stationary multipacting theory for the classic parallel plate geometry. A dedicated, parallel plate experiment is sketched.

  6. Benchmarking reactive transport models at a hillslope scale

    Science.gov (United States)

    Kalbacher, T.; He, W.; Nixdorf, E.; Jang, E.; Fleckenstein, J. H.; Kolditz, O.

    2015-12-01

    The hillslope scale is an important transition between the field scale and the catchment scale. The water flow in the unsaturated zone of a hillslope can be highly dynamic, which can lead to dynamic changes of groundwater flow or stream outflow. Additionally, interactions among host rock formation, soil properties and recharge water from precipitation or anthropogenic activities (mining, agriculture etc.) can influence the water quality of groundwater and stream in the long term. To simulate reactive transport processes at such a scale is a challenging task. On the one hand, simulation of water flow in a coupled soil-aquifer system often involves solving of highly non-linear PDEs such as Richards equation; on the other hand, one has to consider complicated biogeochemical reactions (e.g. water-rock interactions, biological degradation, redox reactions). Both aspects are computationally expensive and have high requirements on the numerical precision and stabilities of the employed code. The primary goals of this study are as follows: i) Identify the bottlenecks and quantitatively analyse their influence on simulation of biogeochemical reactions at a hillslope scale; ii) find or suggest practical strategies to deal with these bottlenecks, thus to provide detailed hints for future improvements of reactive transport simulators. To achieve these goals, the parallelized reactive transport simulator OGS#IPhreeqc has been applied to simulate two benchmark examples. The first example is about uranium leaching based on Šimůnek et al. (2012), which considers the leaching of uranium from a mill tailing and accompanied mineral dissolution/precipitation. The geochemical system is then extended to include redox reactions in the second example. Based on these examples, the numerical stability and parallel performance of the tool is analysed. ReferenceŠimůnek, J., Jacques, D., Šejna, M., van Genuchten, M. T.: The HP2 program for HYDRUS (2D/3D), A coupled code for simulating two

  7. Combining tumor genome simulation with crowdsourcing to benchmark somatic single-nucleotide-variant detection.

    Science.gov (United States)

    Ewing, Adam D; Houlahan, Kathleen E; Hu, Yin; Ellrott, Kyle; Caloian, Cristian; Yamaguchi, Takafumi N; Bare, J Christopher; P'ng, Christine; Waggott, Daryl; Sabelnykova, Veronica Y; Kellen, Michael R; Norman, Thea C; Haussler, David; Friend, Stephen H; Stolovitzky, Gustavo; Margolin, Adam A; Stuart, Joshua M; Boutros, Paul C

    2015-07-01

    The detection of somatic mutations from cancer genome sequences is key to understanding the genetic basis of disease progression, patient survival and response to therapy. Benchmarking is needed for tool assessment and improvement but is complicated by a lack of gold standards, by extensive resource requirements and by difficulties in sharing personal genomic information. To resolve these issues, we launched the ICGC-TCGA DREAM Somatic Mutation Calling Challenge, a crowdsourced benchmark of somatic mutation detection algorithms. Here we report the BAMSurgeon tool for simulating cancer genomes and the results of 248 analyses of three in silico tumors created with it. Different algorithms exhibit characteristic error profiles, and, intriguingly, false positives show a trinucleotide profile very similar to one found in human tumors. Although the three simulated tumors differ in sequence contamination (deviation from normal cell sequence) and in subclonality, an ensemble of pipelines outperforms the best individual pipeline in all cases. BAMSurgeon is available at https://github.com/adamewing/bamsurgeon/.

  8. A resource for benchmarking the usefulness of protein structure models.

    KAUST Repository

    Carbajo, Daniel

    2012-08-02

    BACKGROUND: Increasingly, biologists and biochemists use computational tools to design experiments to probe the function of proteins and/or to engineer them for a variety of different purposes. The most effective strategies rely on the knowledge of the three-dimensional structure of the protein of interest. However it is often the case that an experimental structure is not available and that models of different quality are used instead. On the other hand, the relationship between the quality of a model and its appropriate use is not easy to derive in general, and so far it has been analyzed in detail only for specific application. RESULTS: This paper describes a database and related software tools that allow testing of a given structure based method on models of a protein representing different levels of accuracy. The comparison of the results of a computational experiment on the experimental structure and on a set of its decoy models will allow developers and users to assess which is the specific threshold of accuracy required to perform the task effectively. CONCLUSIONS: The ModelDB server automatically builds decoy models of different accuracy for a given protein of known structure and provides a set of useful tools for their analysis. Pre-computed data for a non-redundant set of deposited protein structures are available for analysis and download in the ModelDB database. IMPLEMENTATION, AVAILABILITY AND REQUIREMENTS: Project name: A resource for benchmarking the usefulness of protein structure models. Project home page: http://bl210.caspur.it/MODEL-DB/MODEL-DB_web/MODindex.php.Operating system(s): Platform independent. Programming language: Perl-BioPerl (program); mySQL, Perl DBI and DBD modules (database); php, JavaScript, Jmol scripting (web server). Other requirements: Java Runtime Environment v1.4 or later, Perl, BioPerl, CPAN modules, HHsearch, Modeller, LGA, NCBI Blast package, DSSP, Speedfill (Surfnet) and PSAIA. License: Free. Any restrictions to use by

  9. Indoor Modelling Benchmark for 3D Geometry Extraction

    Science.gov (United States)

    Thomson, C.; Boehm, J.

    2014-06-01

    A combination of faster, cheaper and more accurate hardware, more sophisticated software, and greater industry acceptance have all laid the foundations for an increased desire for accurate 3D parametric models of buildings. Pointclouds are the data source of choice currently with static terrestrial laser scanning the predominant tool for large, dense volume measurement. The current importance of pointclouds as the primary source of real world representation is endorsed by CAD software vendor acquisitions of pointcloud engines in 2011. Both the capture and modelling of indoor environments require great effort in time by the operator (and therefore cost). Automation is seen as a way to aid this by reducing the workload of the user and some commercial packages have appeared that provide automation to some degree. In the data capture phase, advances in indoor mobile mapping systems are speeding up the process, albeit currently with a reduction in accuracy. As a result this paper presents freely accessible pointcloud datasets of two typical areas of a building each captured with two different capture methods and each with an accurate wholly manually created model. These datasets are provided as a benchmark for the research community to gauge the performance and improvements of various techniques for indoor geometry extraction. With this in mind, non-proprietary, interoperable formats are provided such as E57 for the scans and IFC for the reference model. The datasets can be found at: http://indoor-bench.github.io/indoor-bench.

  10. Extension of PENELOPE to protons: Simulation of nuclear reactions and benchmark with Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Sterpin, E. [Center of Molecular Imaging, Radiotherapy and Oncology, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Avenue Hippocrate 54, 1200 Brussels (Belgium); Sorriaux, J. [Center of Molecular Imaging, Radiotherapy and Oncology, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Avenue Hippocrate 54, 1200 Brussels, Belgium and ICTEAM Institute, Université catholique de Louvain, Louvain-la-Neuve (Belgium); Vynckier, S. [Center of Molecular Imaging, Radiotherapy and Oncology, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Avenue Hippocrate 54, 1200 Brussels, Belgium and Département de radiothérapie, Cliniques Universitaires Saint-Luc, Avenue Hippocrate 10, 1200 Brussels (Belgium)

    2013-11-15

    Purpose: Describing the implementation of nuclear reactions in the extension of the Monte Carlo code (MC) PENELOPE to protons (PENH) and benchmarking with Geant4.Methods: PENH is based on mixed-simulation mechanics for both elastic and inelastic electromagnetic collisions (EM). The adopted differential cross sections for EM elastic collisions are calculated using the eikonal approximation with the Dirac–Hartree–Fock–Slater atomic potential. Cross sections for EM inelastic collisions are computed within the relativistic Born approximation, using the Sternheimer–Liljequist model of the generalized oscillator strength. Nuclear elastic and inelastic collisions were simulated using explicitly the scattering analysis interactive dialin database for {sup 1}H and ICRU 63 data for {sup 12}C, {sup 14}N, {sup 16}O, {sup 31}P, and {sup 40}Ca. Secondary protons, alphas, and deuterons were all simulated as protons, with the energy adapted to ensure consistent range. Prompt gamma emission can also be simulated upon user request. Simulations were performed in a water phantom with nuclear interactions switched off or on and integral depth–dose distributions were compared. Binary-cascade and precompound models were used for Geant4. Initial energies of 100 and 250 MeV were considered. For cases with no nuclear interactions simulated, additional simulations in a water phantom with tight resolution (1 mm in all directions) were performed with FLUKA. Finally, integral depth–dose distributions for a 250 MeV energy were computed with Geant4 and PENH in a homogeneous phantom with, first, ICRU striated muscle and, second, ICRU compact bone.Results: For simulations with EM collisions only, integral depth–dose distributions were within 1%/1 mm for doses higher than 10% of the Bragg-peak dose. For central-axis depth–dose and lateral profiles in a phantom with tight resolution, there are significant deviations between Geant4 and PENH (up to 60%/1 cm for depth

  11. A Web Resource for Standardized Benchmark Datasets, Metrics, and Rosetta Protocols for Macromolecular Modeling and Design.

    Directory of Open Access Journals (Sweden)

    Shane Ó Conchúir

    Full Text Available The development and validation of computational macromolecular modeling and design methods depend on suitable benchmark datasets and informative metrics for comparing protocols. In addition, if a method is intended to be adopted broadly in diverse biological applications, there needs to be information on appropriate parameters for each protocol, as well as metrics describing the expected accuracy compared to experimental data. In certain disciplines, there exist established benchmarks and public resources where experts in a particular methodology are encouraged to supply their most efficient implementation of each particular benchmark. We aim to provide such a resource for protocols in macromolecular modeling and design. We present a freely accessible web resource (https://kortemmelab.ucsf.edu/benchmarks to guide the development of protocols for protein modeling and design. The site provides benchmark datasets and metrics to compare the performance of a variety of modeling protocols using different computational sampling methods and energy functions, providing a "best practice" set of parameters for each method. Each benchmark has an associated downloadable benchmark capture archive containing the input files, analysis scripts, and tutorials for running the benchmark. The captures may be run with any suitable modeling method; we supply command lines for running the benchmarks using the Rosetta software suite. We have compiled initial benchmarks for the resource spanning three key areas: prediction of energetic effects of mutations, protein design, and protein structure prediction, each with associated state-of-the-art modeling protocols. With the help of the wider macromolecular modeling community, we hope to expand the variety of benchmarks included on the website and continue to evaluate new iterations of current methods as they become available.

  12. A Web Resource for Standardized Benchmark Datasets, Metrics, and Rosetta Protocols for Macromolecular Modeling and Design.

    Science.gov (United States)

    Ó Conchúir, Shane; Barlow, Kyle A; Pache, Roland A; Ollikainen, Noah; Kundert, Kale; O'Meara, Matthew J; Smith, Colin A; Kortemme, Tanja

    2015-01-01

    The development and validation of computational macromolecular modeling and design methods depend on suitable benchmark datasets and informative metrics for comparing protocols. In addition, if a method is intended to be adopted broadly in diverse biological applications, there needs to be information on appropriate parameters for each protocol, as well as metrics describing the expected accuracy compared to experimental data. In certain disciplines, there exist established benchmarks and public resources where experts in a particular methodology are encouraged to supply their most efficient implementation of each particular benchmark. We aim to provide such a resource for protocols in macromolecular modeling and design. We present a freely accessible web resource (https://kortemmelab.ucsf.edu/benchmarks) to guide the development of protocols for protein modeling and design. The site provides benchmark datasets and metrics to compare the performance of a variety of modeling protocols using different computational sampling methods and energy functions, providing a "best practice" set of parameters for each method. Each benchmark has an associated downloadable benchmark capture archive containing the input files, analysis scripts, and tutorials for running the benchmark. The captures may be run with any suitable modeling method; we supply command lines for running the benchmarks using the Rosetta software suite. We have compiled initial benchmarks for the resource spanning three key areas: prediction of energetic effects of mutations, protein design, and protein structure prediction, each with associated state-of-the-art modeling protocols. With the help of the wider macromolecular modeling community, we hope to expand the variety of benchmarks included on the website and continue to evaluate new iterations of current methods as they become available.

  13. Benchmark Simulations of the Thermal-Hydraulic Responses during EBR-II Inherent Safety Tests using SAM

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Rui; Sumner, Tyler S.

    2016-01-01

    An advanced system analysis tool SAM is being developed for fast-running, improved-fidelity, and wholeplant transient analyses at Argonne National Laboratory under DOE-NE’s Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. As an important part of code development, companion validation activities are being conducted to ensure the performance and validity of the SAM code. This paper presents the benchmark simulations of two EBR-II tests, SHRT-45R and BOP- 302R, whose data are available through the support of DOE-NE’s Advanced Reactor Technology (ART) program. The code predictions of major primary coolant system parameter are compared with the test results. Additionally, the SAS4A/SASSYS-1 code simulation results are also included for a code-to-code comparison.

  14. A resource for benchmarking the usefulness of protein structure models

    Directory of Open Access Journals (Sweden)

    Carbajo Daniel

    2012-08-01

    Full Text Available Abstract Background Increasingly, biologists and biochemists use computational tools to design experiments to probe the function of proteins and/or to engineer them for a variety of different purposes. The most effective strategies rely on the knowledge of the three-dimensional structure of the protein of interest. However it is often the case that an experimental structure is not available and that models of different quality are used instead. On the other hand, the relationship between the quality of a model and its appropriate use is not easy to derive in general, and so far it has been analyzed in detail only for specific application. Results This paper describes a database and related software tools that allow testing of a given structure based method on models of a protein representing different levels of accuracy. The comparison of the results of a computational experiment on the experimental structure and on a set of its decoy models will allow developers and users to assess which is the specific threshold of accuracy required to perform the task effectively. Conclusions The ModelDB server automatically builds decoy models of different accuracy for a given protein of known structure and provides a set of useful tools for their analysis. Pre-computed data for a non-redundant set of deposited protein structures are available for analysis and download in the ModelDB database. Implementation, availability and requirements Project name: A resource for benchmarking the usefulness of protein structure models. Project home page: http://bl210.caspur.it/MODEL-DB/MODEL-DB_web/MODindex.php. Operating system(s: Platform independent. Programming language: Perl-BioPerl (program; mySQL, Perl DBI and DBD modules (database; php, JavaScript, Jmol scripting (web server. Other requirements: Java Runtime Environment v1.4 or later, Perl, BioPerl, CPAN modules, HHsearch, Modeller, LGA, NCBI Blast package, DSSP, Speedfill (Surfnet and PSAIA. License: Free. Any

  15. Mesoscale Benchmark Demonstration Problem 1: Mesoscale Simulations of Intra-granular Fission Gas Bubbles in UO2 under Post-irradiation Thermal Annealing

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert; Gao, Fei; Sun, Xin; Tonks, Michael; Biner, Bullent; Millet, Paul; Tikare, Veena; Radhakrishnan, Balasubramaniam; Andersson , David

    2012-04-11

    A study was conducted to evaluate the capabilities of different numerical methods used to represent microstructure behavior at the mesoscale for irradiated material using an idealized benchmark problem. The purpose of the mesoscale benchmark problem was to provide a common basis to assess several mesoscale methods with the objective of identifying the strengths and areas of improvement in the predictive modeling of microstructure evolution. In this work, mesoscale models (phase-field, Potts, and kinetic Monte Carlo) developed by PNNL, INL, SNL, and ORNL were used to calculate the evolution kinetics of intra-granular fission gas bubbles in UO2 fuel under post-irradiation thermal annealing conditions. The benchmark problem was constructed to include important microstructural evolution mechanisms on the kinetics of intra-granular fission gas bubble behavior such as the atomic diffusion of Xe atoms, U vacancies, and O vacancies, the effect of vacancy capture and emission from defects, and the elastic interaction of non-equilibrium gas bubbles. An idealized set of assumptions was imposed on the benchmark problem to simplify the mechanisms considered. The capability and numerical efficiency of different models are compared against selected experimental and simulation results. These comparisons find that the phase-field methods, by the nature of the free energy formulation, are able to represent a larger subset of the mechanisms influencing the intra-granular bubble growth and coarsening mechanisms in the idealized benchmark problem as compared to the Potts and kinetic Monte Carlo methods. It is recognized that the mesoscale benchmark problem as formulated does not specifically highlight the strengths of the discrete particle modeling used in the Potts and kinetic Monte Carlo methods. Future efforts are recommended to construct increasingly more complex mesoscale benchmark problems to further verify and validate the predictive capabilities of the mesoscale modeling

  16. Interactive benchmarking

    DEFF Research Database (Denmark)

    Lawson, Lartey; Nielsen, Kurt

    2005-01-01

    We discuss individual learning by interactive benchmarking using stochastic frontier models. The interactions allow the user to tailor the performance evaluation to preferences and explore alternative improvement strategies by selecting and searching the different frontiers using directional...... in the suggested benchmarking tool. The study investigates how different characteristics on dairy farms influences the technical efficiency....

  17. Photochemistry in Terrestrial Exoplanet Atmospheres I: Photochemistry Model and Benchmark Cases

    CERN Document Server

    Hu, Renyu; Bains, William

    2012-01-01

    We present a comprehensive photochemistry model for exploration of the chemical composition of terrestrial exoplanet atmospheres. The photochemistry model is designed from the ground up to have the capacity to treat all types of terrestrial planet atmospheres, ranging from oxidizing through reducing, which makes the code suitable for applications for the wide range of anticipated terrestrial exoplanet compositions. The one-dimensional chemical transport model treats up to 800 chemical reactions, photochemical processes, dry and wet deposition, surface emission and thermal escape of O, H, C, N and S bearing species, as well as formation and deposition of elemental sulfur and sulfuric acid aerosols. We validate the model by computing the atmospheric composition of current Earth and Mars and find agreement with observations of major trace gases in Earth's and Mars' atmospheres. We simulate several plausible atmospheric scenarios of terrestrial exoplanets, and choose three benchmark cases for atmospheres from red...

  18. Development of a benchmarking model for lithium battery electrodes

    Science.gov (United States)

    Bergholz, Timm; Korte, Carsten; Stolten, Detlef

    2016-07-01

    This paper presents a benchmarking model to enable systematic selection of anode and cathode materials for lithium batteries in stationary applications, hybrid and battery electric vehicles. The model incorporates parameters for energy density, power density, safety, lifetime, costs and raw materials. Combinations of carbon anodes, Li4Ti5O12 or TiO2 with LiFePO4 cathodes comprise interesting combinations for application in hybrid power trains. Higher cost and raw material prioritization of stationary applications hinders the breakthrough of Li4Ti5O12, while a combination of TiO2 and LiFePO4 is suggested. The favored combinations resemble state-of-the-art materials, whereas novel cell chemistries must be optimized for cells in battery electric vehicles. In contrast to actual research efforts, sulfur as a cathode material is excluded due to its low volumetric energy density and its known lifetime and safety issues. Lithium as anode materials is discarded due to safety issues linked to electrode melting and dendrite formation. A high capacity composite Li2MnO3·LiNi0.5Co0.5O2 and high voltage spinel LiNi0.5Mn1.5O4 cathode with silicon as anode material promise high energy densities with sufficient lifetime and safety properties if electrochemical and thermal stabilization of the electrolyte/electrode interfaces and bulk materials is achieved. The model allows a systematic top-down orientation of research on lithium batteries.

  19. Piloting a Process Maturity Model as an e-Learning Benchmarking Method

    Science.gov (United States)

    Petch, Jim; Calverley, Gayle; Dexter, Hilary; Cappelli, Tim

    2007-01-01

    As part of a national e-learning benchmarking initiative of the UK Higher Education Academy, the University of Manchester is carrying out a pilot study of a method to benchmark e-learning in an institution. The pilot was designed to evaluate the operational viability of a method based on the e-Learning Maturity Model developed at the University of…

  20. A benchmark study of numerical schemes for one-dimensional arterial blood flow modelling.

    Science.gov (United States)

    Boileau, Etienne; Nithiarasu, Perumal; Blanco, Pablo J; Müller, Lucas O; Fossan, Fredrik Eikeland; Hellevik, Leif Rune; Donders, Wouter P; Huberts, Wouter; Willemet, Marie; Alastruey, Jordi

    2015-10-01

    Haemodynamical simulations using one-dimensional (1D) computational models exhibit many of the features of the systemic circulation under normal and diseased conditions. Recent interest in verifying 1D numerical schemes has led to the development of alternative experimental setups and the use of three-dimensional numerical models to acquire data not easily measured in vivo. In most studies to date, only one particular 1D scheme is tested. In this paper, we present a systematic comparison of six commonly used numerical schemes for 1D blood flow modelling: discontinuous Galerkin, locally conservative Galerkin, Galerkin least-squares finite element method, finite volume method, finite difference MacCormack method and a simplified trapezium rule method. Comparisons are made in a series of six benchmark test cases with an increasing degree of complexity. The accuracy of the numerical schemes is assessed by comparison with theoretical results, three-dimensional numerical data in compatible domains with distensible walls or experimental data in a network of silicone tubes. Results show a good agreement among all numerical schemes and their ability to capture the main features of pressure, flow and area waveforms in large arteries. All the information used in this study, including the input data for all benchmark cases, experimental data where available and numerical solutions for each scheme, is made publicly available online, providing a comprehensive reference data set to support the development of 1D models and numerical schemes.

  1. Model benchmarking and reference signals for angled-beam shear wave ultrasonic nondestructive evaluation (NDE) inspections

    Science.gov (United States)

    Aldrin, John C.; Hopkins, Deborah; Datuin, Marvin; Warchol, Mark; Warchol, Lyudmila; Forsyth, David S.; Buynak, Charlie; Lindgren, Eric A.

    2017-02-01

    For model benchmark studies, the accuracy of the model is typically evaluated based on the change in response relative to a selected reference signal. The use of a side drilled hole (SDH) in a plate was investigated as a reference signal for angled beam shear wave inspection for aircraft structure inspections of fastener sites. Systematic studies were performed with varying SDH depth and size, and varying the ultrasonic probe frequency, focal depth, and probe height. Increased error was observed with the simulation of angled shear wave beams in the near-field. Even more significant, asymmetry in real probes and the inherent sensitivity of signals in the near-field to subtle test conditions were found to provide a greater challenge with achieving model agreement. To achieve quality model benchmark results for this problem, it is critical to carefully align the probe with the part geometry, to verify symmetry in probe response, and ideally avoid using reference signals from the near-field response. Suggested reference signals for angled beam shear wave inspections include using the `through hole' corner specular reflection signal and the full skip' signal off of the far wall from the side drilled hole.

  2. Benchmark models, planes lines and points for future SUSY searches at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    AbdusSalam, S.S. [The Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Allanach, B.C. [Cambridge Univ. (United Kingdom). Dept. of Applied Mathematics and Theoretical Physics; Dreiner, H.K. [Bonn Univ. (DE). Bethe Center for Theoretical Physics and Physikalisches Inst.] (and others)

    2012-03-15

    We define benchmark models for SUSY searches at the LHC, including the CMSSM, NUHM, mGMSB, mAMSB, MM-AMSB and p19MSSM, as well as models with R-parity violation and the NMSSM. Within the parameter spaces of these models, we propose benchmark subspaces, including planes, lines and points along them. The planes may be useful for presenting results of the experimental searches in different SUSY scenarios, while the specific benchmark points may serve for more detailed detector performance tests and comparisons. We also describe algorithms for defining suitable benchmark points along the proposed lines in the parameter spaces, and we define a few benchmark points motivated by recent fits to existing experimental data.

  3. A unified framework for benchmark dose estimation applied to mixed models and model averaging

    DEFF Research Database (Denmark)

    Ritz, Christian; Gerhard, Daniel; Hothorn, Ludwig A.

    2013-01-01

    This article develops a framework for benchmark dose estimation that allows intrinsically nonlinear dose-response models to be used for continuous data in much the same way as is already possible for quantal data. This means that the same dose-response model equations may be applied to both...

  4. Simulation of hydrogen deflagration experiment – Benchmark exercise with lumped-parameter codes

    Energy Technology Data Exchange (ETDEWEB)

    Kljenak, Ivo, E-mail: ivo.kljenak@ijs.si [Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Kuznetsov, Mikhail, E-mail: mike.kuznetsov@kit.edu [Karlsruhe Institute of Technology, Kaiserstraße 12, 76131 Karlsruhe (Germany); Kostka, Pal, E-mail: kostka@nubiki.hu [NUBIKI Nuclear Safety Research Institute, Konkoly-Thege Miklós út 29-33, 1121 Budapest (Hungary); Kubišova, Lubica, E-mail: lubica.kubisova@ujd.gov.sk [Nuclear Regulatory Authority of the Slovak Republic, Bajkalská 27, 82007 Bratislava (Slovakia); Maltsev, Mikhail, E-mail: maltsev_MB@aep.ru [JSC Atomenergoproekt, 1, st. Podolskykh Kursantov, Moscow (Russian Federation); Manzini, Giovanni, E-mail: giovanni.manzini@rse-web.it [Ricerca sul Sistema Energetico, Via Rubattino 54, 20134 Milano (Italy); Povilaitis, Mantas, E-mail: mantas.p@mail.lei.lt [Lithuania Energy Institute, Breslaujos g.3, 44403 Kaunas (Lithuania)

    2015-03-15

    Highlights: • Blind and open simulations of hydrogen combustion experiment in large-scale containment-like facility with different lumped-parameter codes. • Simulation of axial as well as radial flame propagation. • Confirmation of adequacy of lumped-parameter codes for safety analyses of actual nuclear power plants. - Abstract: An experiment on hydrogen deflagration (Upward Flame Propagation Experiment – UFPE) was proposed by the Jozef Stefan Institute (Slovenia) and performed in the HYKA A2 facility at the Karlsruhe Institute of Technology (Germany). The experimental results were used to organize a benchmark exercise for lumped-parameter codes. Six organizations (JSI, AEP, LEI, NUBIKI, RSE and UJD SR) participated in the benchmark exercise, using altogether four different computer codes: ANGAR, ASTEC, COCOSYS and ECART. Both blind and open simulations were performed. In general, all the codes provided satisfactory results of the pressure increase, whereas the results of the temperature show a wider dispersal. Concerning the flame axial and radial velocities, the results may be considered satisfactory, given the inherent simplification of the lumped-parameter description compared to the local instantaneous description.

  5. Generation IV benchmarking of TRISO fuel performance models under accident conditions: Modeling input data

    Energy Technology Data Exchange (ETDEWEB)

    Collin, Blaise P. [Idaho National Laboratory (INL), Idaho Falls, ID (United States)

    2014-09-01

    This document presents the benchmark plan for the calculation of particle fuel performance on safety testing experiments that are representative of operational accidental transients. The benchmark is dedicated to the modeling of fission product release under accident conditions by fuel performance codes from around the world, and the subsequent comparison to post-irradiation experiment (PIE) data from the modeled heating tests. The accident condition benchmark is divided into three parts: the modeling of a simplified benchmark problem to assess potential numerical calculation issues at low fission product release; the modeling of the AGR-1 and HFR-EU1bis safety testing experiments; and, the comparison of the AGR-1 and HFR-EU1bis modeling results with PIE data. The simplified benchmark case, thereafter named NCC (Numerical Calculation Case), is derived from ''Case 5'' of the International Atomic Energy Agency (IAEA) Coordinated Research Program (CRP) on coated particle fuel technology [IAEA 2012]. It is included so participants can evaluate their codes at low fission product release. ''Case 5'' of the IAEA CRP-6 showed large code-to-code discrepancies in the release of fission products, which were attributed to ''effects of the numerical calculation method rather than the physical model''[IAEA 2012]. The NCC is therefore intended to check if these numerical effects subsist. The first two steps imply the involvement of the benchmark participants with a modeling effort following the guidelines and recommendations provided by this document. The third step involves the collection of the modeling results by Idaho National Laboratory (INL) and the comparison of these results with the available PIE data. The objective of this document is to provide all necessary input data to model the benchmark cases, and to give some methodology guidelines and recommendations in order to make all results suitable for comparison

  6. Summary of FY15 results of benchmark modeling activities

    Energy Technology Data Exchange (ETDEWEB)

    Arguello, J. Guadalupe [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    Sandia is participating in the third phase of an is a contributing partner to a U.S.-German "Joint Project" entitled "Comparison of current constitutive models and simulation procedures on the basis of model calculations of the thermo-mechanical behavior and healing of rock salt." The first goal of the project is to check the ability of numerical modeling tools to correctly describe the relevant deformation phenomena in rock salt under various influences. Achieving this goal will lead to increased confidence in the results of numerical simulations related to the secure storage of radioactive wastes in rock salt, thereby enhancing the acceptance of the results. These results may ultimately be used to make various assertions regarding both the stability analysis of an underground repository in salt, during the operating phase, and the long-term integrity of the geological barrier against the release of harmful substances into the biosphere, in the post-operating phase.

  7. Tree-ring responses to extreme climate events as benchmarks for terrestrial dynamic vegetation models

    Directory of Open Access Journals (Sweden)

    A. Rammig

    2014-02-01

    Full Text Available Climate extremes can trigger exceptional responses in terrestrial ecosystems, for instance by altering growth or mortality rates. Effects of this kind are often manifested in reductions of the local net primary production (NPP. Investigating a set of European long-term data on annual radial tree growth confirms this pattern: we find that 53% of tree ring width (TRW indices are below one standard deviation, and up to 16% of the TRW values are below two standard deviations in years with extremely high temperatures and low precipitation. Based on these findings we investigate if climate driven patterns in long-term tree growth data may serve as benchmarks for state-of-the-art dynamic vegetation models such as LPJmL. The model simulates NPP but not explicitly the radial tree ring growth, hence requiring a generic method to ensure an objective comparison. Here we propose an analysis scheme that quantifies the coincidence rate of climate extremes with some biotic responses (here TRW or simulated NPP. We find that the reduction in tree-ring width during drought extremes is lower than the corresponding reduction of simulated NPP. We identify ten extreme years during the 20th century in which both, model and measurements indicate high coincidence rates across Europe. However, we detect substantial regional differences in simulated and observed responses to extreme events. One explanation for this discrepancy could be that the tree-ring data have preferentially been sampled at more climatically stressed sites. The model-data difference is amplified by the fact that dynamic vegetation models are designed to simulate mean ecosystem responses at landscape or regional scale. However, we find that both model-data and measurements display carry-over effects from the previous year. We conclude that using radial tree growth is a good basis for generic model-benchmarks if the data are analyzed by scale-free measures such as coincidence analysis. Our study shows

  8. SCALE Modeling of Selected Neutronics Test Problems within the OECD UAM LWR’s Benchmark

    Directory of Open Access Journals (Sweden)

    Luigi Mercatali

    2013-01-01

    Full Text Available The OECD UAM Benchmark was launched in 2005 with the objective of determining the uncertainty in the simulation of Light Water Reactors (LWRs system calculations at all the stages of the coupled reactor physics—thermal hydraulics modeling. Within the framework of the “Neutronics Phase” of the Benchmark the solutions of some selected test cases at the cell physics and lattice physics levels are presented. The SCALE 6.1 code package has been used for the neutronics modeling of the selected exercises. Sensitivity and Uncertainty analysis (S/U based on the generalized perturbation theory has been performed in order to assess the uncertainty of the computation of some selected reactor integral parameters due to the uncertainty in the basic nuclear data. As a general trend, it has been found that the main sources of uncertainty are the 238U (n, and the 239Pu nubar for the UOX- and the MOX-fuelled test cases, respectively. Moreover, the reference solutions for the test cases obtained using Monte Carlo methodologies together with a comparison between deterministic and stochastic solutions are presented.

  9. Multi-Site Model Benchmarking: Do Land Surface Models Leak Information?

    Science.gov (United States)

    Mocko, D. M.; Nearing, G. S.; Kumar, S.

    2014-12-01

    It is widely reported that land surface models (LSMs) are unable to use all of the information available from boundary conditions [1-4]. Evidence for this is that statistical models typically out-perform physics LSMs with the same forcing data. We demonstrate that this conclusion is not necessarily correct. The statistical models don't consider parameters, and the experiments cannot distinguish between information loss and bad information (disinformation). Recent work has outlined a rigorous interpretation of model benchmarking that allows us to measure the amount of information provided by model physics and the amount of information lost due to model error [5]. Recognizing that a complete understanding of model adequacy requires treatment across multiple locations [6] allows us to expand benchmarking theory to segregate bad and missing information. The result is a benchmarking method that that can distinguish error due to parameters, forcing data, and model structure - and, unlike other approaches, does not rely on parameter estimation, which can only provide estimates of parameter uncertainty conditional on model physics. Our new benchmarking methodology was compared with the standard methodology to measure information loss in several LSMs included in the current and developmental generations of the North American Land Data Assimilation System. The classical experiments implied that each of these models lose a significant amount of information from the forcing data; however, the new methodology shows clearly that this information did not actually exist in the boundary conditions in the first place. Almost all model bias can be attributed to incorrect parameters, and that most of the LSMs actually add information (via model physics) to what is available in the boundary conditions. 1 Abramowitz, G., Geophys Res Let 32, (2005). 2 Gupta, H. V., et al., Water Resour Res 48, (2012). 3 Luo, Y. Q. et al., Biogeosciences 9, (2012). 4 Han, E., et al., J Hydromet (2014). 5

  10. Construct validity and expert benchmarking of the haptic virtual reality dental simulator.

    Science.gov (United States)

    Suebnukarn, Siriwan; Chaisombat, Monthalee; Kongpunwijit, Thanapohn; Rhienmora, Phattanapon

    2014-10-01

    The aim of this study was to demonstrate construct validation of the haptic virtual reality (VR) dental simulator and to define expert benchmarking criteria for skills assessment. Thirty-four self-selected participants (fourteen novices, fourteen intermediates, and six experts in endodontics) at one dental school performed ten repetitions of three mode tasks of endodontic cavity preparation: easy (mandibular premolar with one canal), medium (maxillary premolar with two canals), and hard (mandibular molar with three canals). The virtual instrument's path length was registered by the simulator. The outcomes were assessed by an expert. The error scores in easy and medium modes accurately distinguished the experts from novices and intermediates at the onset of training, when there was a significant difference between groups (ANOVA, pbenchmarking criteria for optimal performance.

  11. Physical Model Development and Benchmarking for MHD Flows in Blanket Design

    Energy Technology Data Exchange (ETDEWEB)

    Ramakanth Munipalli; P.-Y.Huang; C.Chandler; C.Rowell; M.-J.Ni; N.Morley; S.Smolentsev; M.Abdou

    2008-06-05

    An advanced simulation environment to model incompressible MHD flows relevant to blanket conditions in fusion reactors has been developed at HyPerComp in research collaboration with TEXCEL. The goals of this phase-II project are two-fold: The first is the incorporation of crucial physical phenomena such as induced magnetic field modeling, and extending the capabilities beyond fluid flow prediction to model heat transfer with natural convection and mass transfer including tritium transport and permeation. The second is the design of a sequence of benchmark tests to establish code competence for several classes of physical phenomena in isolation as well as in select (termed here as “canonical”,) combinations. No previous attempts to develop such a comprehensive MHD modeling capability exist in the literature, and this study represents essentially uncharted territory. During the course of this Phase-II project, a significant breakthrough was achieved in modeling liquid metal flows at high Hartmann numbers. We developed a unique mathematical technique to accurately compute the fluid flow in complex geometries at extremely high Hartmann numbers (10,000 and greater), thus extending the state of the art of liquid metal MHD modeling relevant to fusion reactors at the present time. These developments have been published in noted international journals. A sequence of theoretical and experimental results was used to verify and validate the results obtained. The code was applied to a complete DCLL module simulation study with promising results.

  12. Theory, modeling, and simulation annual report, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    This report briefly discusses research on the following topics: development of electronic structure methods; modeling molecular processes in clusters; modeling molecular processes in solution; modeling molecular processes in separations chemistry; modeling interfacial molecular processes; modeling molecular processes in the atmosphere; methods for periodic calculations on solids; chemistry and physics of minerals; graphical user interfaces for computational chemistry codes; visualization and analysis of molecular simulations; integrated computational chemistry environment; and benchmark computations.

  13. Benchmarking of Computational Models for NDE and SHM of Composites

    Science.gov (United States)

    Wheeler, Kevin; Leckey, Cara; Hafiychuk, Vasyl; Juarez, Peter; Timucin, Dogan; Schuet, Stefan; Hafiychuk, Halyna

    2016-01-01

    Ultrasonic wave phenomena constitute the leading physical mechanism for nondestructive evaluation (NDE) and structural health monitoring (SHM) of solid composite materials such as carbon-fiber-reinforced polymer (CFRP) laminates. Computational models of ultrasonic guided-wave excitation, propagation, scattering, and detection in quasi-isotropic laminates can be extremely valuable in designing practically realizable NDE and SHM hardware and software with desired accuracy, reliability, efficiency, and coverage. This paper presents comparisons of guided-wave simulations for CFRP composites implemented using three different simulation codes: two commercial finite-element analysis packages, COMSOL and ABAQUS, and a custom code implementing the Elastodynamic Finite Integration Technique (EFIT). Comparisons are also made to experimental laser Doppler vibrometry data and theoretical dispersion curves.

  14. Semi-active model predictive control for 3rd generation benchmark problem using smart dampers

    Institute of Scientific and Technical Information of China (English)

    Yan Guiyun; Sun Bingnan; Lü Yanping

    2007-01-01

    A semi-active strategy for model predictive control (MPC), in which magneto-rheological dampers are used as an actuator, is presented for use in reducing the nonlinear seismic response of high-rise buildings. A multi-step predictive model is developed to estimate the seismic performance of high-rise buildings, taking into account of the effects of nonlinearity, time-variability, model mismatching, and disturbances and uncertainty of controlled system parameters by the predicted error feedback in the multi-step predictive model. Based on the predictive model, a Kalman-Bucy observer suitable for semi-active strategy is proposed to estimate the state vector from the acceleration and semi-active control force feedback.The main advantage of the proposed strategy is its inherent stability, simplicity, on-line real-time operation, and the ability to handle nonlinearity, uncertainty, and time-variability properties of structures. Numerical simulation of the nonlinear seismic responses of a controlled 20-story benchmark building is carried out, and the simulation results are compared to those of other control systems. The results show that the developed semi-active strategy can efficiently reduce the nonlinear seismic response of high-rise buildings.

  15. Multiple-code benchmark simulation study of coupled THMC processesin the excavation disturbed zone associated with geological nuclear wasterepositories

    Energy Technology Data Exchange (ETDEWEB)

    Rutqvist, J.; Feng, X-T.; Hudson, J.; Jing, L.; Kobayashi, A.; Koyama, T.; Pan, P-Z.; Lee, H-S.; Rinne, M.; Sonnenthal, E.; Yamamoto, Y.

    2006-05-10

    An international, multiple-code benchmark test (BMT) studyis being conducted within the international DECOVALEX project to analysecoupled thermal, hydrological, mechanical and chemical (THMC) processesin the excavation disturbed zone (EDZ) around emplacement drifts of anuclear waste repository. This BMT focuses on mechanical responses andlong-term chemo-mechanical effects that may lead to changes in mechanicaland hydrological properties in the EDZ. This includes time-de-pendentprocesses such as creep, and subcritical crack, or healing of fracturesthat might cause "weakening" or "hardening" of the rock over the longterm. Five research teams are studying this BMT using a wide range ofmodel approaches, including boundary element, finite element, and finitedifference, particle mechanics, and elasto-plastic cellular automatamethods. This paper describes the definition of the problem andpreliminary simulation results for the initial model inception part, inwhich time dependent effects are not yet included.

  16. 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......) with the Anaerobic Digestion Model No. 1 (ADM1). We use BSM2 as a vehicle to compare two different 1-D SST models, and to assess the relative significance of their performance on WWTP simulation model outputs. The two 1-D SST models assessed include the firstorder model by Takács et al. [1991] and the second...

  17. Towards a public, standardized, diagnostic benchmarking system for land surface models

    Directory of Open Access Journals (Sweden)

    G. Abramowitz

    2012-02-01

    Full Text Available We examine different conceptions of land surface model benchmarking and illustrate the importance of internationally standardized evaluation experiments that specify data sets, variables, metrics and model resolutions. We additionally show how essential the definition of a priori expectations of model performance can be, based on the complexity of a model and the amount of information being provided to it, and give an example of how these expectations might be quantified. Finally, we introduce the Protocol for the Analysis of Land Surface models (PALS, a free, online land surface model benchmarking application, and show how it is structured to meet both of these goals.

  18. Towards a public, standardized, diagnostic benchmarking system for land surface models

    Directory of Open Access Journals (Sweden)

    G. Abramowitz

    2012-06-01

    Full Text Available This work examines different conceptions of land surface model benchmarking and the importance of internationally standardized evaluation experiments that specify data sets, variables, metrics and model resolutions. It additionally demonstrates how essential the definition of a priori expectations of model performance can be, based on the complexity of a model and the amount of information being provided to it, and gives an example of how these expectations might be quantified. Finally, the Protocol for the Analysis of Land Surface models (PALS is introduced – a free, online land surface model benchmarking application that is structured to meet both of these goals.

  19. Photochemistry in Terrestrial Exoplanet Atmospheres. I. Photochemistry Model and Benchmark Cases

    Science.gov (United States)

    Hu, Renyu; Seager, Sara; Bains, William

    2012-12-01

    We present a comprehensive photochemistry model for exploration of the chemical composition of terrestrial exoplanet atmospheres. The photochemistry model is designed from the ground up to have the capacity to treat all types of terrestrial planet atmospheres, ranging from oxidizing through reducing, which makes the code suitable for applications for the wide range of anticipated terrestrial exoplanet compositions. The one-dimensional chemical transport model treats up to 800 chemical reactions, photochemical processes, dry and wet deposition, surface emission, and thermal escape of O, H, C, N, and S bearing species, as well as formation and deposition of elemental sulfur and sulfuric acid aerosols. We validate the model by computing the atmospheric composition of current Earth and Mars and find agreement with observations of major trace gases in Earth's and Mars' atmospheres. We simulate several plausible atmospheric scenarios of terrestrial exoplanets and choose three benchmark cases for atmospheres from reducing to oxidizing. The most interesting finding is that atomic hydrogen is always a more abundant reactive radical than the hydroxyl radical in anoxic atmospheres. Whether atomic hydrogen is the most important removal path for a molecule of interest also depends on the relevant reaction rates. We also find that volcanic carbon compounds (i.e., CH4 and CO2) are chemically long-lived and tend to be well mixed in both reducing and oxidizing atmospheres, and their dry deposition velocities to the surface control the atmospheric oxidation states. Furthermore, we revisit whether photochemically produced oxygen can cause false positives for detecting oxygenic photosynthesis, and find that in 1 bar CO2-rich atmospheres oxygen and ozone may build up to levels that have conventionally been accepted as signatures of life, if there is no surface emission of reducing gases. The atmospheric scenarios presented in this paper can serve as the benchmark atmospheres for

  20. Benchmark of the FLUKA model of crystal channeling against the UA9-H8 experiment

    Science.gov (United States)

    Schoofs, P.; Cerutti, F.; Ferrari, A.; Smirnov, G.

    2015-07-01

    Channeling in bent crystals is increasingly considered as an option for the collimation of high-energy particle beams. The installation of crystals in the LHC has taken place during this past year and aims at demonstrating the feasibility of crystal collimation and a possible cleaning efficiency improvement. The performance of CERN collimation insertions is evaluated with the Monte Carlo code FLUKA, which is capable to simulate energy deposition in collimators as well as beam loss monitor signals. A new model of crystal channeling was developed specifically so that similar simulations can be conducted in the case of crystal-assisted collimation. In this paper, most recent results of this model are brought forward in the framework of a joint activity inside the UA9 collaboration to benchmark the different simulation tools available. The performance of crystal STF 45, produced at INFN Ferrara, was measured at the H8 beamline at CERN in 2010 and serves as the basis to the comparison. Distributions of deflected particles are shown to be in very good agreement with experimental data. Calculated dechanneling lengths and crystal performance in the transition region between amorphous regime and volume reflection are also close to the measured ones.

  1. Current modeling practice may lead to falsely high benchmark dose estimates.

    Science.gov (United States)

    Ringblom, Joakim; Johanson, Gunnar; Öberg, Mattias

    2014-07-01

    Benchmark dose (BMD) modeling is increasingly used as the preferred approach to define the point-of-departure for health risk assessment of chemicals. As data are inherently variable, there is always a risk to select a model that defines a lower confidence bound of the BMD (BMDL) that, contrary to expected, exceeds the true BMD. The aim of this study was to investigate how often and under what circumstances such anomalies occur under current modeling practice. Continuous data were generated from a realistic dose-effect curve by Monte Carlo simulations using four dose groups and a set of five different dose placement scenarios, group sizes between 5 and 50 animals and coefficients of variations of 5-15%. The BMD calculations were conducted using nested exponential models, as most BMD software use nested approaches. "Non-protective" BMDLs (higher than true BMD) were frequently observed, in some scenarios reaching 80%. The phenomenon was mainly related to the selection of the non-sigmoidal exponential model (Effect=a·e(b)(·dose)). In conclusion, non-sigmoid models should be used with caution as it may underestimate the risk, illustrating that awareness of the model selection process and sound identification of the point-of-departure is vital for health risk assessment.

  2. Benchmarking biological nutrient removal in wastewater treatment plants: influence of mathematical model assumptions.

    Science.gov (United States)

    Flores-Alsina, Xavier; Gernaey, Krist V; Jeppsson, Ulf

    2012-01-01

    This paper examines the effect of different model assumptions when describing biological nutrient removal (BNR) by the activated sludge models (ASM) 1, 2d & 3. The performance of a nitrogen removal (WWTP1) and a combined nitrogen and phosphorus removal (WWTP2) benchmark wastewater treatment plant was compared for a series of model assumptions. Three different model approaches describing BNR are considered. In the reference case, the original model implementations are used to simulate WWTP1 (ASM1 & 3) and WWTP2 (ASM2d). The second set of models includes a reactive settler, which extends the description of the non-reactive TSS sedimentation and transport in the reference case with the full set of ASM processes. Finally, the third set of models is based on including electron acceptor dependency of biomass decay rates for ASM1 (WWTP1) and ASM2d (WWTP2). The results show that incorporation of a reactive settler: (1) increases the hydrolysis of particulates; (2) increases the overall plant's denitrification efficiency by reducing the S(NOx) concentration at the bottom of the clarifier; (3) increases the oxidation of COD compounds; (4) increases X(OHO) and X(ANO) decay; and, finally, (5) increases the growth of X(PAO) and formation of X(PHA,Stor) for ASM2d, which has a major impact on the whole P removal system. Introduction of electron acceptor dependent decay leads to a substantial increase of the concentration of X(ANO), X(OHO) and X(PAO) in the bottom of the clarifier. The paper ends with a critical discussion of the influence of the different model assumptions, and emphasizes the need for a model user to understand the significant differences in simulation results that are obtained when applying different combinations of 'standard' models.

  3. Application of a Data-Driven Fuzzy Control Design to a Wind Turbine Benchmark Model

    Directory of Open Access Journals (Sweden)

    Silvio Simani

    2012-01-01

    Full Text Available In general, the modelling of wind turbines is a challenging task, since they are complex dynamic systems, whose aerodynamics are nonlinear and unsteady. Accurate models should contain many degrees of freedom, and their control algorithm design must account for these complexities. However, these algorithms must capture the most important turbine dynamics without being too complex and unwieldy, mainly when they have to be implemented in real-time applications. The first contribution of this work consists of providing an application example of the design and testing through simulations, of a data-driven fuzzy wind turbine control. In particular, the strategy is based on fuzzy modelling and identification approaches to model-based control design. Fuzzy modelling and identification can represent an alternative for developing experimental models of complex systems, directly derived directly from measured input-output data without detailed system assumptions. Regarding the controller design, this paper suggests again a fuzzy control approach for the adjustment of both the wind turbine blade pitch angle and the generator torque. The effectiveness of the proposed strategies is assessed on the data sequences acquired from the considered wind turbine benchmark. Several experiments provide the evidence of the advantages of the proposed regulator with respect to different control methods.

  4. Adsorption, X-ray Diffraction, Photoelectron, and Atomic Emission Spectroscopy Benchmark Studies for the Eighth Industrial Fluid Properties Simulation Challenge*+

    Science.gov (United States)

    Ross, Richard B.; Aeschliman, David B.; Ahmad, Riaz; Brennan, John K.; Brostrom, Myles L.; Frankel, Kevin A.; Moore, Jonathan D.; Moore, Joshua D.; Mountain, Raymond D.; Poirier, Derrick M.; Thommes, Matthias; Shen, Vincent K.; Schultz, Nathan E.; Siderius, Daniel W.; Smith, Kenneth D.

    2016-01-01

    The primary goal of the eighth industrial fluid properties simulation challenge was to test the ability of molecular simulation methods to predict the adsorption of organic adsorbates in activated carbon materials. The challenge focused on the adsorption of perfluorohexane in the activated carbon standard BAM-P109 (Panne and Thünemann 2010). Entrants were challenged to predict the adsorption of perfluorohexane in the activated carbon at a temperature of 273 K and at relative pressures of 0.1, 0.3, and 0.6. The relative pressure (P/Po) is defined as that relative to the bulk saturation pressure predicted by the fluid model at a given temperature (273 K in this case). The predictions were judged by comparison to a set of experimentally determined values, which are published here for the first time and were not disclosed to the entrants prior to the challenge. Benchmark experimental studies, described herein, were also carried out and provided to entrants in order to aid in the development of new force fields and simulation methods to be employed in the challenge. These studies included argon, carbon dioxide, and water adsorption in the BAM-P109 activated carbon as well as X-ray diffraction, X-ray microtomography, photoelectron spectroscopy, and atomic emission spectroscopy studies of BAM-P109. Several concurrent studies were carried out for the BAM-P108 activated carbon (Panne and Thünemann 2010). These are included in the current manuscript for comparison. PMID:27840543

  5. A new methodology for building energy benchmarking: An approach based on clustering concept and statistical models

    Science.gov (United States)

    Gao, Xuefeng

    Though many building energy benchmarking programs have been developed during the past decades, they hold certain limitations. The major concern is that they may cause misleading benchmarking due to not fully considering the impacts of the multiple features of buildings on energy performance. The existing methods classify buildings according to only one of many features of buildings -- the use type, which may result in a comparison between two buildings that are tremendously different in other features and not properly comparable as a result. This research aims to tackle this challenge by proposing a new methodology based on the clustering concept and statistical analysis. The clustering concept, which reflects on machine learning algorithms, classifies buildings based on a multi-dimensional domain of building features, rather than the single dimension of use type. Buildings with the greatest similarity of features that influence energy performance are classified into the same cluster, and benchmarked according to the centroid reference of the cluster. Statistical analysis is applied to find the most influential features impacting building energy performance, as well as provide prediction models for the new design energy consumption. The proposed methodology as applicable to both existing building benchmarking and new design benchmarking was discussed in this dissertation. The former contains four steps: feature selection, clustering algorithm adaptation, results validation, and interpretation. The latter consists of three parts: data observation, inverse modeling, and forward modeling. The experimentation and validation were carried out for both perspectives. It was shown that the proposed methodology could account for the total building energy performance and was able to provide a more comprehensive approach to benchmarking. In addition, the multi-dimensional clustering concept enables energy benchmarking among different types of buildings, and inspires a new

  6. Benchmarking the Calculation of Stochastic Heating and Emissivity of Dust Grains in the Context of Radiative Transfer Simulations

    CERN Document Server

    Camps, Peter; Bianchi, Simone; Lunttila, Tuomas; Pinte, Christophe; Natale, Giovanni; Juvela, Mika; Fischera, Joerg; Fitzgerald, Michael P; Gordon, Karl; Baes, Maarten; Steinacker, Juergen

    2015-01-01

    We define an appropriate problem for benchmarking dust emissivity calculations in the context of radiative transfer (RT) simulations, specifically including the emission from stochastically heated dust grains. Our aim is to provide a self-contained guide for implementors of such functionality, and to offer insights in the effects of the various approximations and heuristics implemented by the participating codes to accelerate the calculations. The benchmark problem definition includes the optical and calorimetric material properties, and the grain size distributions, for a typical astronomical dust mixture with silicate, graphite and PAH components; a series of analytically defined radiation fields to which the dust population is to be exposed; and instructions for the desired output. We process this problem using six RT codes participating in this benchmark effort, and compare the results to a reference solution computed with the publicly available dust emission code DustEM. The participating codes implement...

  7. Benchmarking biological nutrient removal in wastewater treatment plants: influence of mathematical model assumptions

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Gernaey, Krist V.; Jeppsson, Ulf

    2012-01-01

    This paper examines the effect of different model assumptions when describing biological nutrient removal (BNR) by the activated sludge models (ASM) 1, 2d & 3. The performance of a nitrogen removal (WWTP1) and a combined nitrogen and phosphorus removal (WWTP2) benchmark wastewater treatment plant...

  8. Benchmarking nuclear models of FLUKA and GEANT4 for carbon ion therapy

    Energy Technology Data Exchange (ETDEWEB)

    Boehlen, T T; Cerutti, F; Dosanjh, M; Ferrari, A [European Organization for Nuclear Research CERN, CH-1211, Geneva 23 (Switzerland); Gudowska, I [Medical Radiation Physics, Karolinska Institutet and Stockholm University, Box 260 S-171 76 Stockholm (Sweden); Mairani, A [INFN Milan, Via Celoria 16, 20133 Milan (Italy); Quesada, J M, E-mail: Till.Tobias.Boehlen@cern.c [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla (Spain)

    2010-10-07

    As carbon ions, at therapeutic energies, penetrate tissue, they undergo inelastic nuclear reactions and give rise to significant yields of secondary fragment fluences. Therefore, an accurate prediction of these fluences resulting from the primary carbon interactions is necessary in the patient's body in order to precisely simulate the spatial dose distribution and the resulting biological effect. In this paper, the performance of nuclear fragmentation models of the Monte Carlo transport codes, FLUKA and GEANT4, in tissue-like media and for an energy regime relevant for therapeutic carbon ions is investigated. The ability of these Monte Carlo codes to reproduce experimental data of charge-changing cross sections and integral and differential yields of secondary charged fragments is evaluated. For the fragment yields, the main focus is on the consideration of experimental approximations and uncertainties such as the energy measurement by time-of-flight. For GEANT4, the hadronic models G4BinaryLightIonReaction and G4QMD are benchmarked together with some recently enhanced de-excitation models. For non-differential quantities, discrepancies of some tens of percent are found for both codes. For differential quantities, even larger deviations are found. Implications of these findings for the therapeutic use of carbon ions are discussed.

  9. Modeling of the ORNL PCA Benchmark Using SCALE6.0 Hybrid Deterministic-Stochastic Methodology

    Directory of Open Access Journals (Sweden)

    Mario Matijević

    2013-01-01

    Full Text Available Revised guidelines with the support of computational benchmarks are needed for the regulation of the allowed neutron irradiation to reactor structures during power plant lifetime. Currently, US NRC Regulatory Guide 1.190 is the effective guideline for reactor dosimetry calculations. A well known international shielding database SINBAD contains large selection of models for benchmarking neutron transport methods. In this paper a PCA benchmark has been chosen from SINBAD for qualification of our methodology for pressure vessel neutron fluence calculations, as required by the Regulatory Guide 1.190. The SCALE6.0 code package, developed at Oak Ridge National Laboratory, was used for modeling of the PCA benchmark. The CSAS6 criticality sequence of the SCALE6.0 code package, which includes KENO-VI Monte Carlo code, as well as MAVRIC/Monaco hybrid shielding sequence, was utilized for calculation of equivalent fission fluxes. The shielding analysis was performed using multigroup shielding library v7_200n47g derived from general purpose ENDF/B-VII.0 library. As a source of response functions for reaction rate calculations with MAVRIC we used international reactor dosimetry libraries (IRDF-2002 and IRDF-90.v2 and appropriate cross-sections from transport library v7_200n47g. The comparison of calculational results and benchmark data showed a good agreement of the calculated and measured equivalent fission fluxes.

  10. Benchmarking of Monte Carlo simulation of bremsstrahlung from thick targets at radiotherapy energies

    Energy Technology Data Exchange (ETDEWEB)

    Faddegon, Bruce A.; Asai, Makoto; Perl, Joseph; Ross, Carl; Sempau, Josep; Tinslay, Jane; Salvat, Francesc [Department of Radiation Oncology, University of California at San Francisco, San Francisco, California 94143 (United States); Stanford Linear Accelerator Center, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); National Research Council Canada, Institute for National Measurement Standards, 1200 Montreal Road, Building M-36, Ottawa, Ontario K1A 0R6 (Canada); Institut de Tecniques Energetiques, Universitat Politecnica de Catalunya and Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), Diagonal 647, 08028 Barcelona (Spain); Stanford Linear Accelerator Center, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Facultat de Fisica (ECM), Universitat de Barcelona, Societat Catalana de Fisica (IEC), Diagonal 647, 08028 Barcelona (Spain)

    2008-10-15

    Several Monte Carlo systems were benchmarked against published measurements of bremsstrahlung yield from thick targets for 10-30 MV beams. The quantity measured was photon fluence at 1 m per unit energy per incident electron (spectra), and total photon fluence, integrated over energy, per incident electron (photon yield). Results were reported at 10-30 MV on the beam axis for Al and Pb targets and at 15 MV at angles out to 90 degree sign for Be, Al, and Pb targets. Beam energy was revised with improved accuracy of 0.5% using an improved energy calibration of the accelerator. Recently released versions of the Monte Carlo systems EGSNRC, GEANT4, and PENELOPE were benchmarked against the published measurements using the revised beam energies. Monte Carlo simulation was capable of calculation of photon yield in the experimental geometry to 5% out to 30 degree sign , 10% at wider angles, and photon spectra to 10% at intermediate photon energies, 15% at lower energies. Accuracy of measured photon yield from 0 to 30 degree sign was 5%, 1 s.d., increasing to 7% for the larger angles. EGSNRC and PENELOPE results were within 2 s.d. of the measured photon yield at all beam energies and angles, GEANT4 within 3 s.d. Photon yield at nonzero angles for angles covering conventional field sizes used in radiotherapy (out to 10 degree sign ), measured with an accuracy of 3%, was calculated within 1 s.d. of measurement for EGSNRC, 2 s.d. for PENELOPE and GEANT4. Calculated spectra closely matched measurement at photon energies over 5 MeV. Photon spectra near 5 MeV were underestimated by as much as 10% by all three codes. The photon spectra below 2-3 MeV for the Be and Al targets and small angles were overestimated by up to 15% when using EGSNRC and PENELOPE, 20% with GEANT4. EGSNRC results with the NIST option for the bremsstrahlung cross section were preferred over the alternative cross section available in EGSNRC and over EGS4. GEANT4 results calculated with the &apos

  11. Analysis of Transitional and Turbulent Flow Through the FDA Benchmark Nozzle Model Using Laser Doppler Velocimetry.

    Science.gov (United States)

    Taylor, Joshua O; Good, Bryan C; Paterno, Anthony V; Hariharan, Prasanna; Deutsch, Steven; Malinauskas, Richard A; Manning, Keefe B

    2016-09-01

    Transitional and turbulent flow through a simplified medical device model is analyzed as part of the FDA's Critical Path Initiative, designed to improve the process of bringing medical products to market. Computational predictions are often used in the development of devices and reliable in vitro data is needed to validate computational results, particularly estimations of the Reynolds stresses that could play a role in damaging blood elements. The high spatial resolution of laser Doppler velocimetry (LDV) is used to collect two component velocity data within the FDA benchmark nozzle model. Two flow conditions are used to produce flow encompassing laminar, transitional, and turbulent regimes, and viscous stresses, principal Reynolds stresses, and turbulence intensities are calculated from the measured LDV velocities. Axial velocities and viscous stresses are compared to data from a prior inter-laboratory study conducted with particle image velocimetry. Large velocity gradients are observed near the wall in the nozzle throat and in the jet shear layer located in the expansion downstream of the throat, with axial velocity changing as much as 4.5 m/s over 200 μm. Additionally, maximum Reynolds shear stresses of 1000-2000 Pa are calculated in the high shear regions, which are an order of magnitude higher than the peak viscous shear stresses (<100 Pa). It is important to consider the effects of both viscous and turbulent stresses when simulating flow through medical devices. Reynolds stresses above commonly accepted hemolysis thresholds are measured in the nozzle model, indicating that hemolysis may occur under certain flow conditions. As such, the presented turbulence quantities from LDV, which are also available for download at https://fdacfd.nci.nih.gov/ , provide an ideal validation test for computational simulations that seek to characterize the flow field and to predict hemolysis within the FDA nozzle geometry.

  12. Structural modeling and fuzzy-logic based diagnosis of a ship propulsion benchmark

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Blanke, M.; Katebi, S.D.

    2000-01-01

    An analysis of structural model of a ship propulsion benchmark leads to identifying the subsystems with inherent redundant information. For a nonlinear part of the system, a Fuzzy logic based FD algorithm with adaptive threshold is employed. The results illustrate the applicability of structural...

  13. Creating a benchmark of vertical axis wind turbines in dynamic stall for validating numerical models

    DEFF Research Database (Denmark)

    Castelein, D.; Ragni, D.; Tescione, G.;

    2015-01-01

    An experimental campaign using Particle Image Velocimetry (2C-PIV) technique has been conducted on a H-type Vertical Axis Wind Turbine (VAWT) to create a benchmark for validating and comparing numerical models. The turbine is operated at tip speed ratios (TSR) of 4.5 and 2, at an average chord-ba...

  14. Developing of Indicators of an E-Learning Benchmarking Model for Higher Education Institutions

    Science.gov (United States)

    Sae-Khow, Jirasak

    2014-01-01

    This study was the development of e-learning indicators used as an e-learning benchmarking model for higher education institutes. Specifically, it aimed to: 1) synthesize the e-learning indicators; 2) examine content validity by specialists; and 3) explore appropriateness of the e-learning indicators. Review of related literature included…

  15. An Analysis of Academic Research Libraries Assessment Data: A Look at Professional Models and Benchmarking Data

    Science.gov (United States)

    Lewin, Heather S.; Passonneau, Sarah M.

    2012-01-01

    This research provides the first review of publicly available assessment information found on Association of Research Libraries (ARL) members' websites. After providing an overarching review of benchmarking assessment data, and of professionally recommended assessment models, this paper examines if libraries contextualized their assessment…

  16. Structural modeling and fuzzy-logic based diagnosis of a ship propulsion benchmark

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Blanke, M.; Katebi, S.D.

    2000-01-01

    An analysis of structural model of a ship propulsion benchmark leads to identifying the subsystems with inherent redundant information. For a nonlinear part of the system, a Fuzzy logic based FD algorithm with adaptive threshold is employed. The results illustrate the applicability of structural...... analysis as well as fuzzy observer....

  17. NACA 0012 benchmark model experimental flutter results with unsteady pressure distributions

    Science.gov (United States)

    Rivera, Jose A., Jr.; Dansberry, Bryan E.; Bennett, Robert M.; Durham, Michael H.; Silva, Walter A.

    1992-01-01

    The Structural Dynamics Division at NASA Langley Research Center has started a wind tunnel activity referred to as the Benchmark Models Program. The primary objective of the program is to acquire measured dynamic instability and corresponding pressure data that will be useful for developing and evaluating aeroelastic type CFD codes currently in use or under development. The program is a multi-year activity that will involve testing of several different models to investigate various aeroelastic phenomena. This paper describes results obtained from a second wind tunnel test of the first model in the Benchmark Models Program. This first model consisted of a rigid semispan wing having a rectangular planform and a NACA 0012 airfoil shape which was mounted on a flexible two degree-of-freedom mount system. Experimental flutter boundaries and corresponding unsteady pressure distribution data acquired over two model chords located at the 60 and 95 percent span stations are presented.

  18. Benchmark Dose Software Development and Maintenance Ten Berge Cxt Models

    Science.gov (United States)

    This report is intended to provide an overview of beta version 1.0 of the implementation of a concentration-time (CxT) model originally programmed and provided by Wil ten Berge (referred to hereafter as the ten Berge model). The recoding and development described here represent ...

  19. Pore-scale and Continuum Simulations of Solute Transport Micromodel Benchmark Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Oostrom, Martinus; Mehmani, Yashar; Romero Gomez, Pedro DJ; Tang, Y.; Liu, H.; Yoon, Hongkyu; Kang, Qinjun; Joekar Niasar, Vahid; Balhoff, Matthew; Dewers, T.; Tartakovsky, Guzel D.; Leist, Emily AE; Hess, Nancy J.; Perkins, William A.; Rakowski, Cynthia L.; Richmond, Marshall C.; Serkowski, John A.; Werth, Charles J.; Valocchi, Albert J.; Wietsma, Thomas W.; Zhang, Changyong

    2016-08-01

    Four sets of micromodel nonreactive solute transport experiments were conducted with flow velocity, grain diameter, pore-aspect ratio, and flow focusing heterogeneity as the variables. The data sets were offered to pore-scale modeling groups to test their simulators. Each set consisted of two learning experiments, for which all results was made available, and a challenge experiment, for which only the experimental description and base input parameters were provided. The experimental results showed a nonlinear dependence of the dispersion coefficient on the Peclet number, a negligible effect of the pore-aspect ratio on transverse mixing, and considerably enhanced mixing due to flow focusing. Five pore-scale models and one continuum-scale model were used to simulate the experiments. Of the pore-scale models, two used a pore-network (PN) method, two others are based on a lattice-Boltzmann (LB) approach, and one employed a computational fluid dynamics (CFD) technique. The learning experiments were used by the PN models to modify the standard perfect mixing approach in pore bodies into approaches to simulate the observed incomplete mixing. The LB and CFD models used these experiments to appropriately discretize the grid representations. The continuum model use published non-linear relations between transverse dispersion coefficients and Peclet numbers to compute the required dispersivity input values. Comparisons between experimental and numerical results for the four challenge experiments show that all pore-scale models were all able to satisfactorily simulate the experiments. The continuum model underestimated the required dispersivity values and, resulting in less dispersion. The PN models were able to complete the simulations in a few minutes, whereas the direct models needed up to several days on supercomputers to resolve the more complex problems.

  20. Calculation of benchmarks with a shear beam model

    NARCIS (Netherlands)

    Ferreira, D.

    2015-01-01

    Fiber models for beam and shell elements allow for relatively rapid finite element analysis of concrete structures and structural elements. This project aims at the development of the formulation of such elements and a pilot implementation. Standard nonlinear fiber beam formulations do not account

  1. RANS Modeling of Benchmark Shockwave / Boundary Layer Interaction Experiments

    Science.gov (United States)

    Georgiadis, Nick; Vyas, Manan; Yoder, Dennis

    2010-01-01

    This presentation summarizes the computations of a set of shock wave / turbulent boundary layer interaction (SWTBLI) test cases using the Wind-US code, as part of the 2010 American Institute of Aeronautics and Astronautics (AIAA) shock / boundary layer interaction workshop. The experiments involve supersonic flows in wind tunnels with a shock generator that directs an oblique shock wave toward the boundary layer along one of the walls of the wind tunnel. The Wind-US calculations utilized structured grid computations performed in Reynolds-averaged Navier-Stokes mode. Three turbulence models were investigated: the Spalart-Allmaras one-equation model, the Menter Shear Stress Transport wavenumber-angular frequency two-equation model, and an explicit algebraic stress wavenumber-angular frequency formulation. Effects of grid resolution and upwinding scheme were also considered. The results from the CFD calculations are compared to particle image velocimetry (PIV) data from the experiments. As expected, turbulence model effects dominated the accuracy of the solutions with upwinding scheme selection indicating minimal effects.!

  2. Models of asthma: density-equalizing mapping and output benchmarking

    Directory of Open Access Journals (Sweden)

    Fischer Tanja C

    2008-02-01

    Full Text Available Abstract Despite the large amount of experimental studies already conducted on bronchial asthma, further insights into the molecular basics of the disease are required to establish new therapeutic approaches. As a basis for this research different animal models of asthma have been developed in the past years. However, precise bibliometric data on the use of different models do not exist so far. Therefore the present study was conducted to establish a data base of the existing experimental approaches. Density-equalizing algorithms were used and data was retrieved from a Thomson Institute for Scientific Information database. During the period from 1900 to 2006 a number of 3489 filed items were connected to animal models of asthma, the first being published in the year 1968. The studies were published by 52 countries with the US, Japan and the UK being the most productive suppliers, participating in 55.8% of all published items. Analyzing the average citation per item as an indicator for research quality Switzerland ranked first (30.54/item and New Zealand ranked second for countries with more than 10 published studies. The 10 most productive journals included 4 with a main focus allergy and immunology and 4 with a main focus on the respiratory system. Two journals focussed on pharmacology or pharmacy. In all assigned subject categories examined for a relation to animal models of asthma, immunology ranked first. Assessing numbers of published items in relation to animal species it was found that mice were the preferred species followed by guinea pigs. In summary it can be concluded from density-equalizing calculations that the use of animal models of asthma is restricted to a relatively small number of countries. There are also differences in the use of species. These differences are based on variations in the research focus as assessed by subject category analysis.

  3. Benchmarks and models for 1-D radiation transport in stochastic participating media

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D S

    2000-08-21

    Benchmark calculations for radiation transport coupled to a material temperature equation in a 1-D slab and 1-D spherical geometry binary random media are presented. The mixing statistics are taken to be homogeneous Markov statistics in the 1-D slab but only approximately Markov statistics in the 1-D sphere. The material chunk sizes are described by Poisson distribution functions. The material opacities are first taken to be constant and then allowed to vary as a strong function of material temperature. Benchmark values and variances for time evolution of the ensemble average of material temperature energy density and radiation transmission are computed via a Monte Carlo type method. These benchmarks are used as a basis for comparison with three other approximate methods of solution. One of these approximate methods is simple atomic mix. The second approximate model is an adaptation of what is commonly called the Levermore-Pomraning model and which is referred to here as the standard model. It is shown that recasting the temperature coupling as a type of effective scattering can be useful in formulating the third approximate model, an adaptation of a model due to Su and Pomraning which attempts to account for the effects of scattering in a stochastic context. This last adaptation shows consistent improvement over both the atomic mix and standard models when used in the 1-D slab geometry but shows limited improvement in the 1-D spherical geometry. Benchmark values are also computed for radiation transmission from the 1-D sphere without material heating present. This is to evaluate the performance of the standard model on this geometry--something which has never been done before. All of the various tests demonstrate the importance of stochastic structure on the solution. Also demonstrated are the range of usefulness and limitations of a simple atomic mix formulation.

  4. A Review of Flood Loss Models as Basis for Harmonization and Benchmarking.

    Science.gov (United States)

    Gerl, Tina; Kreibich, Heidi; Franco, Guillermo; Marechal, David; Schröter, Kai

    2016-01-01

    Risk-based approaches have been increasingly accepted and operationalized in flood risk management during recent decades. For instance, commercial flood risk models are used by the insurance industry to assess potential losses, establish the pricing of policies and determine reinsurance needs. Despite considerable progress in the development of loss estimation tools since the 1980s, loss estimates still reflect high uncertainties and disparities that often lead to questioning their quality. This requires an assessment of the validity and robustness of loss models as it affects prioritization and investment decision in flood risk management as well as regulatory requirements and business decisions in the insurance industry. Hence, more effort is needed to quantify uncertainties and undertake validations. Due to a lack of detailed and reliable flood loss data, first order validations are difficult to accomplish, so that model comparisons in terms of benchmarking are essential. It is checked if the models are informed by existing data and knowledge and if the assumptions made in the models are aligned with the existing knowledge. When this alignment is confirmed through validation or benchmarking exercises, the user gains confidence in the models. Before these benchmarking exercises are feasible, however, a cohesive survey of existing knowledge needs to be undertaken. With that aim, this work presents a review of flood loss-or flood vulnerability-relationships collected from the public domain and some professional sources. Our survey analyses 61 sources consisting of publications or software packages, of which 47 are reviewed in detail. This exercise results in probably the most complete review of flood loss models to date containing nearly a thousand vulnerability functions. These functions are highly heterogeneous and only about half of the loss models are found to be accompanied by explicit validation at the time of their proposal. This paper exemplarily presents

  5. A Review of Flood Loss Models as Basis for Harmonization and Benchmarking.

    Directory of Open Access Journals (Sweden)

    Tina Gerl

    Full Text Available Risk-based approaches have been increasingly accepted and operationalized in flood risk management during recent decades. For instance, commercial flood risk models are used by the insurance industry to assess potential losses, establish the pricing of policies and determine reinsurance needs. Despite considerable progress in the development of loss estimation tools since the 1980s, loss estimates still reflect high uncertainties and disparities that often lead to questioning their quality. This requires an assessment of the validity and robustness of loss models as it affects prioritization and investment decision in flood risk management as well as regulatory requirements and business decisions in the insurance industry. Hence, more effort is needed to quantify uncertainties and undertake validations. Due to a lack of detailed and reliable flood loss data, first order validations are difficult to accomplish, so that model comparisons in terms of benchmarking are essential. It is checked if the models are informed by existing data and knowledge and if the assumptions made in the models are aligned with the existing knowledge. When this alignment is confirmed through validation or benchmarking exercises, the user gains confidence in the models. Before these benchmarking exercises are feasible, however, a cohesive survey of existing knowledge needs to be undertaken. With that aim, this work presents a review of flood loss-or flood vulnerability-relationships collected from the public domain and some professional sources. Our survey analyses 61 sources consisting of publications or software packages, of which 47 are reviewed in detail. This exercise results in probably the most complete review of flood loss models to date containing nearly a thousand vulnerability functions. These functions are highly heterogeneous and only about half of the loss models are found to be accompanied by explicit validation at the time of their proposal. This paper

  6. Algorithm comparison and benchmarking using a parallel spectra transform shallow water model

    Energy Technology Data Exchange (ETDEWEB)

    Worley, P.H. [Oak Ridge National Lab., TN (United States); Foster, I.T.; Toonen, B. [Argonne National Lab., IL (United States)

    1995-04-01

    In recent years, a number of computer vendors have produced supercomputers based on a massively parallel processing (MPP) architecture. These computers have been shown to be competitive in performance with conventional vector supercomputers for some applications. As spectral weather and climate models are heavy users of vector supercomputers, it is interesting to determine how these models perform on MPPS, and which MPPs are best suited to the execution of spectral models. The benchmarking of MPPs is complicated by the fact that different algorithms may be more efficient on different architectures. Hence, a comprehensive benchmarking effort must answer two related questions: which algorithm is most efficient on each computer and how do the most efficient algorithms compare on different computers. In general, these are difficult questions to answer because of the high cost associated with implementing and evaluating a range of different parallel algorithms on each MPP platform.

  7. Network Generation Model Based on Evolution Dynamics To Generate Benchmark Graphs

    CERN Document Server

    Pasta, Muhammad Qasim

    2016-01-01

    Network generation models provide an understanding of the dynamics behind the formation and evolution of different networks including social networks, technological networks and biological networks. Two important applications of these models are to study the evolution dynamics of network formation and to generate benchmark networks with known community structures. Research has been conducted in both these directions relatively independent of the other application area. This creates a disjunct between real world networks and the networks generated to study community detection algorithms. In this paper, we propose to study both these application areas together i.e.\\ introduce a network generation model based on evolution dynamics of real world networks and generate networks with community structures that can be used as benchmark graphs to study community detection algorithms. The generated networks possess tunable modular structures which can be used to generate networks with known community structures. We stud...

  8. Upgrading the Benchmark Simulation Model Framework with emerging challenges - A study of N2O emissions and the fate of pharmaceuticals in urban wastewater systems

    OpenAIRE

    Snip, Laura; Plósz, Benedek G.; Flores Alsina, Xavier; Jeppsson, Ulf A. C.; Gernaey, Krist

    2015-01-01

    I dag forventes der at et spildevandsrensningsanlæg ikke kun fjerner de almindelige forurenende stoffer fra spildevandet. Indenfor de seneste årtier er mange nye udfordringer opstået, hvilket har markant øget kravene til rensningsanlæggene. For eksempel forventes et rensningsanlæg nu til dags også at minimere sit CO2‐aftryk (carbon footprint) og fjerne mikroforureninger fra spildevandet. Optimering af driften af et rensningsanlæg kan undersøges og forbedres ved brug af matematiske modeller, d...

  9. Generative Benchmark Models for Mesoscale Structures in Multilayer Networks

    CERN Document Server

    Bazzi, Marya; Arenas, Alex; Howison, Sam D; Porter, Mason A

    2016-01-01

    Multilayer networks allow one to represent diverse and interdependent connectivity patterns --- e.g., time-dependence, multiple subsystems, or both --- that arise in many applications and which are difficult or awkward to incorporate into standard network representations. In the study of multilayer networks, it is important to investigate "mesoscale" (i.e., intermediate-scale) structures, such as dense sets of nodes known as "communities" that are connected sparsely to each other, to discover network features that are not apparent at the microscale or the macroscale. A variety of methods and algorithms are available to identify communities in multilayer networks, but they differ in their definitions and/or assumptions of what constitutes a community, and many scalable algorithms provide approximate solutions with little or no theoretical guarantee on the quality of their approximations. Consequently, it is crucial to develop generative models of networks to use as a common test of community-detection tools. I...

  10. Benchmarking of computer codes and approaches for modeling exposure scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, R.R. [EG and G Idaho, Inc., Idaho Falls, ID (United States); Rittmann, P.D.; Wood, M.I. [Westinghouse Hanford Co., Richland, WA (United States); Cook, J.R. [Westinghouse Savannah River Co., Aiken, SC (United States)

    1994-08-01

    The US Department of Energy Headquarters established a performance assessment task team (PATT) to integrate the activities of DOE sites that are preparing performance assessments for the disposal of newly generated low-level waste. The PATT chartered a subteam with the task of comparing computer codes and exposure scenarios used for dose calculations in performance assessments. This report documents the efforts of the subteam. Computer codes considered in the comparison include GENII, PATHRAE-EPA, MICROSHIELD, and ISOSHLD. Calculations were also conducted using spreadsheets to provide a comparison at the most fundamental level. Calculations and modeling approaches are compared for unit radionuclide concentrations in water and soil for the ingestion, inhalation, and external dose pathways. Over 30 tables comparing inputs and results are provided.

  11. Benchmarking of thermal hydraulic loop models for Lead-Alloy Cooled Advanced Nuclear Energy System (LACANES), phase-I: Isothermal steady state forced convection

    Science.gov (United States)

    Cho, Jae Hyun; Batta, A.; Casamassima, V.; Cheng, X.; Choi, Yong Joon; Hwang, Il Soon; Lim, Jun; Meloni, P.; Nitti, F. S.; Dedul, V.; Kuznetsov, V.; Komlev, O.; Jaeger, W.; Sedov, A.; Kim, Ji Hak; Puspitarini, D.

    2011-08-01

    As highly promising coolant for new generation nuclear reactors, liquid Lead-Bismuth Eutectic has been extensively worldwide investigated. With high expectation about this advanced coolant, a multi-national systematic study on LBE was proposed in 2007, which covers benchmarking of thermal hydraulic prediction models for Lead-Alloy Cooled Advanced Nuclear Energy System (LACANES). This international collaboration has been organized by OECD/NEA, and nine organizations - ENEA, ERSE, GIDROPRESS, IAEA, IPPE, KIT/IKET, KIT/INR, NUTRECK, and RRC KI - contribute their efforts to LACANES benchmarking. To produce experimental data for LACANES benchmarking, thermal-hydraulic tests were conducted by using a 12-m tall LBE integral test facility, named as Heavy Eutectic liquid metal loop for integral test of Operability and Safety of PEACER (HELIOS) which has been constructed in 2005 at the Seoul National University in the Republic of Korea. LACANES benchmark campaigns consist of a forced convection (phase-I) and a natural circulation (phase-II). In the forced convection case, the predictions of pressure losses based on handbook correlations and that obtained by Computational Fluid Dynamics code simulation were compared with the measured data for various components of the HELIOS test facility. Based on comparative analyses of the predictions and the measured data, recommendations for the prediction methods of a pressure loss in LACANES were obtained. In this paper, results for the forced convection case (phase-I) of LACANES benchmarking are described.

  12. Results of the 2016 UT modeling benchmark proposed by the French Atomic Energy Commission (CEA) obtained with models implemented in CIVA software

    Science.gov (United States)

    Toullelan, Gwénaël; Chatillon, Sylvain; Raillon, Raphaële; Mahaut, Steve; Lonné, Sébastien; Bannouf, Souad

    2017-02-01

    For several years, the World Federation of NDE Centers, WFNDEC, proposes benchmark studies in which simulated results (in either ultrasonic, X-rays or eddy current NDT configurations) obtained with various models are compared to experiments. This year the proposed UT benchmark proposed by CEA concerns inspection configurations with multi-skips echoes i.e. the incident beam undergoes several skips on the surface and bottom of the specimen before interacting with the defect. This technique is commonly used to inspect thin specimen and/or in case of limited access inspection. This technique relies on the use of T45° mode in order to avoid mode conversion and to facilitate the interpretation of the echoes. The inspections were carried out with two probes of different aperture working at 5MHz.

  13. 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

  14. GEANT4 simulations of the n{sub T}OF spallation source and their benchmarking

    Energy Technology Data Exchange (ETDEWEB)

    Lo Meo, S. [Research Centre ' ' Ezio Clementel' ' , ENEA, Bologna (Italy); Section of Bologna, INFN, Bologna (Italy); Cortes-Giraldo, M.A.; Lerendegui-Marco, J.; Guerrero, C.; Quesada, J.M. [Universidad de Sevilla, Facultad de Fisica, Sevilla (Spain); Massimi, C.; Vannini, G. [Section of Bologna, INFN, Bologna (Italy); University of Bologna, Physics and Astronomy Dept. ' ' Alma Mater Studiorum' ' , Bologna (Italy); Barbagallo, M.; Colonna, N. [INFN, Section of Bari, Bari (Italy); Mancusi, D. [CEA-Saclay, DEN, DM2S, SERMA, LTSD, Gif-sur-Yvette CEDEX (France); Mingrone, F. [Section of Bologna, INFN, Bologna (Italy); Sabate-Gilarte, M. [Universidad de Sevilla, Facultad de Fisica, Sevilla (Spain); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Vlachoudis, V. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Collaboration: The n_TOF Collaboration

    2015-12-15

    Neutron production and transport in the spallation target of the n{sub T}OF facility at CERN has been simulated with GEANT4. The results obtained with different models of high-energy nucleon-nucleus interaction have been compared with the measured characteristics of the neutron beam, in particular the flux and its dependence on neutron energy, measured in the first experimental area. The best agreement at present, within 20% for the absolute value of the flux, and within few percent for the energy dependence in the whole energy range from thermal to 1 GeV, is obtained with the INCL++ model coupled with the GEANT4 native de-excitation model. All other available models overestimate by a larger factor, of up to 70%, the n{sub T}OF neutron flux. The simulations are also able to accurately reproduce the neutron beam energy resolution function, which is essentially determined by the moderation time inside the target/moderator assembly. The results here reported provide confidence on the use of GEANT4 for simulations of spallation neutron sources. (orig.)

  15. A simulation benchmark to evaluate the performance of advanced control techniques in biological wastewater treatment plants

    OpenAIRE

    Sotomayor O.A.Z.; Park S.W.; Garcia C

    2001-01-01

    Wastewater treatment plants (WWTP) are complex systems that incorporate a large number of biological, physicochemical and biochemical processes. They are large and nonlinear systems subject to great disturbances in incoming loads. The primary goal of a WWTP is to reduce pollutants and the second goal is disturbance rejection, in order to obtain good effluent quality. Modeling and computer simulations are key tools in the achievement of these two goals. They are essential to describe, predict ...

  16. Assessing reactor physics codes capabilities to simulate fast reactors on the example of the BN-600 benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Vladimir [Scientific and Engineering Centre for Nuclear and Radiation Safety (SES NRS), Moscow (Russian Federation); Bousquet, Jeremy [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Garching (Germany)

    2016-11-15

    This work aims to assess the capabilities of reactor physics codes (initially validated for thermal reactors) to simulate fast sodium cooled reactors. The BFS-62-3A critical experiment from the BN-600 Hybrid Core Benchmark Analyses was chosen for the investigation. Monte-Carlo codes (KENO from SCALE and SERPENT 2.1.23) and the deterministic diffusion code DYN3D-MG are applied to calculate the neutronic parameters. It was found that the multiplication factor and reactivity effects calculated by KENO and SERPENT using the ENDF/B-VII.0 continuous energy library are in a good agreement with each other and with the measured benchmark values. Few-groups macroscopic cross sections, required for DYN3D-MG, were prepared in applying different methods implemented in SCALE and SERPENT. The DYN3D-MG results of a simplified benchmark show reasonable agreement with results from Monte-Carlo calculations and measured values. The former results are used to justify DYN3D-MG implementation for sodium cooled fast reactors coupled deterministic analysis.

  17. LHC Benchmark Scenarios for the Real Higgs Singlet Extension of the Standard Model

    CERN Document Server

    Robens, Tania

    2016-01-01

    We present benchmark scenarios for searches for an additional Higgs state in the real Higgs singlet extension of the Standard Model in Run 2 of the LHC. The scenarios are selected such that they fulfill all relevant current theoretical and experimental constraints, but can potentially be discovered at the current LHC run. We take into account the results presented in earlier work and update the experimental constraints from relevant LHC Higgs searches and signal rate measurements. The benchmark scenarios are given separately for the low mass and high mass region, i.e. the mass range where the additional Higgs state is lighter or heavier than the discovered Higgs state at around 125 GeV. They have also been presented in the framework of the LHC Higgs Cross Section Working Group.

  18. LHC benchmark scenarios for the real Higgs singlet extension of the standard model

    Energy Technology Data Exchange (ETDEWEB)

    Robens, Tania [TU Dresden, Institut fuer Kern- und Teilchenphysik, Dresden (Germany); Stefaniak, Tim [University of California, Department of Physics and Santa Cruz Institute for Particle Physics, Santa Cruz, CA (United States)

    2016-05-15

    We present benchmark scenarios for searches for an additional Higgs state in the real Higgs singlet extension of the Standard Model in Run 2 of the LHC. The scenarios are selected such that they fulfill all relevant current theoretical and experimental constraints, but can potentially be discovered at the current LHC run. We take into account the results presented in earlier work and update the experimental constraints from relevant LHC Higgs searches and signal rate measurements. The benchmark scenarios are given separately for the low-mass and high-mass region, i.e. the mass range where the additional Higgs state is lighter or heavier than the discovered Higgs state at around 125 GeV. They have also been presented in the framework of the LHC Higgs Cross Section Working Group. (orig.)

  19. A Base Integer Programming Model and Benchmark Suite for Liner-Shipping Network Design

    DEFF Research Database (Denmark)

    Brouer, Berit Dangaard; Alvarez, Fernando; Plum, Christian Edinger Munk

    2014-01-01

    sources of liner shipping for OR researchers in general. We describe and analyze the liner-shipping domain applied to network design and present a rich integer programming model based on services that constitute the fixed schedule of a liner shipping company. We prove the liner-shipping network design...... problem to be strongly NP-hard. A benchmark suite of data instances to reflect the business structure of a global liner shipping network is presented. The design of the benchmark suite is discussed in relation to industry standards, business rules, and mathematical programming. The data are based on real......The liner-shipping network design problem is to create a set of nonsimple cyclic sailing routes for a designated fleet of container vessels that jointly transports multiple commodities. The objective is to maximize the revenue of cargo transport while minimizing the costs of operation...

  20. The effect of coupled mass transport and internal reforming on modeling of solid oxide fuel cells part II: Benchmarking transient response and dynamic model fidelity assessment

    Science.gov (United States)

    Albrecht, Kevin J.; Braun, Robert J.

    2016-02-01

    One- and 'quasi' two-dimensional (2-D) dynamic, interface charge transport models of a solid oxide fuel cell (SOFC) developed previously in a companion paper, are benchmarked against other models and simulated to evaluate the effects of coupled transport and chemistry. Because the reforming reaction can distort the concentration profiles of the species within the anode, a 'quasi' 2-D model that captures porous media mass transport and electrochemistry is required. The impact of a change in concentration at the triple-phase boundary is twofold wherein the local Nernst potential and anode exchange current densities are influenced, thereby altering the current density and temperature distributions of the cell. Thus, the dynamic response of the cell models are compared, and benchmarked against previous channel-level models to gauge the relative importance of capturing in-situ reforming phenomena on cell performance. Simulation results indicate differences in the transient electrochemical response for a step in current density where the 'quasi' 2-D model predicts a slower rise and fall in cell potential due to the additional volume of the porous media and mass transport dynamics. Delays in fuel flow rate are shown to increase the difference observed in the electrochemical response of the cells.

  1. CFD Simulation of Thermal-Hydraulic Benchmark V1000CT-2 Using ANSYS CFX

    OpenAIRE

    2009-01-01

    Plant measured data from VVER-1000 coolant mixing experiments were used within the OECD/NEA and AER coupled code benchmarks for light water reactors to test and validate computational fluid dynamic (CFD) codes. The task is to compare the various calculations with measured data, using specified boundary conditions and core power distributions. The experiments, which are provided for CFD validation, include single loop cooling down or heating-up by disturbing the heat transfer in the steam gene...

  2. Benchmark of a new multi-ion-species collision operator for $\\delta f$ Monte Carlo neoclassical simulation

    CERN Document Server

    Satake, Shinsuke; Pianpanit, Theerasarn; Sugama, Hideo; Nunami, Masanori; Matsuoka, Seikichi; Ishiguro, Seiji; Kanno, Ryutaro

    2016-01-01

    A numerical method to implement a linearized Coulomb collision operator for multi-ion-species neoclassical transport simulation using two-weight $\\delta f$ Monte Carlo method is developed. The conservation properties and the adjointness of the operator in the collisions between two particle species with different temperatures are verified. The linearized operator in a $\\delta f$ Monte Carlo code is benchmarked with other two kinetic simulation codes, i. e., a $\\delta f$ continuum gyrokinetic code with the same linearized collision operator and a full-f PIC code with Nanbu collision operator. The benchmark simulations of the equilibration process of plasma flow and temperature fluctuation among several particle species show very good agreement between $\\delta f$ Monte Carlo code and the other two codes. An error in the H-theorem in the two-weight $\\delta f$ Monte Carlo method is found, which is caused by the weight spreading phenomenon inherent in the two-weight $\\delta f$ method. It is demonstrated that the w...

  3. A Cooperative Activity on Quenching Process Simulation--- Japanese IMS-VHT Project on the Benchmark Analysis and Experiment ---

    Institute of Scientific and Technical Information of China (English)

    Tatsuo Inoue; Youichi Watanabe; Kazuo Okamura; Michiharu Narazaki; Hayato Shichino; Dong-Ying Ju; Hideo Kanamori; Katsumi Ichitani

    2004-01-01

    Japanese IMS-VHT project on the Virtual Heat Treatment tool for monitoring and optimising HT process in relation with the international cooperative programs is briefly introduced. This project motivates to develop virtual tools for computer to optimize the heat treatment condition and to support decision for HT operation by knowledge based database in addition to process simulation. As one of the activities with the cooperation of the Society of Materials Science, Japan and the Japan Society for Heat Treatment, a benchmark project is undergoing. This includes simulation of carburized quenching process of a cylinder, disc, and ring as well as a helical gear by use of common data of materials properties and cooling characteristics by several available simulation programs. A part of the newly obtained results is presented as an interim report.

  4. A parallel high-order accurate finite element nonlinear Stokes ice sheet model and benchmark experiments

    Energy Technology Data Exchange (ETDEWEB)

    Leng, Wei [Chinese Academy of Sciences; Ju, Lili [University of South Carolina; Gunzburger, Max [Florida State University; Price, Stephen [Los Alamos National Laboratory; Ringler, Todd [Los Alamos National Laboratory,

    2012-01-01

    The numerical modeling of glacier and ice sheet evolution is a subject of growing interest, in part because of the potential for models to inform estimates of global sea level change. This paper focuses on the development of a numerical model that determines the velocity and pressure fields within an ice sheet. Our numerical model features a high-fidelity mathematical model involving the nonlinear Stokes system and combinations of no-sliding and sliding basal boundary conditions, high-order accurate finite element discretizations based on variable resolution grids, and highly scalable parallel solution strategies, all of which contribute to a numerical model that can achieve accurate velocity and pressure approximations in a highly efficient manner. We demonstrate the accuracy and efficiency of our model by analytical solution tests, established ice sheet benchmark experiments, and comparisons with other well-established ice sheet models.

  5. Benchmark Modeling of the Near-Field and Far-Field Wave Effects of Wave Energy Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Rhinefrank, Kenneth E; Haller, Merrick C; Ozkan-Haller, H Tuba

    2013-01-26

    This project is an industry-led partnership between Columbia Power Technologies and Oregon State University that will perform benchmark laboratory experiments and numerical modeling of the near-field and far-field impacts of wave scattering from an array of wave energy devices. These benchmark experimental observations will help to fill a gaping hole in our present knowledge of the near-field effects of multiple, floating wave energy converters and are a critical requirement for estimating the potential far-field environmental effects of wave energy arrays. The experiments will be performed at the Hinsdale Wave Research Laboratory (Oregon State University) and will utilize an array of newly developed Buoys' that are realistic, lab-scale floating power converters. The array of Buoys will be subjected to realistic, directional wave forcing (1:33 scale) that will approximate the expected conditions (waves and water depths) to be found off the Central Oregon Coast. Experimental observations will include comprehensive in-situ wave and current measurements as well as a suite of novel optical measurements. These new optical capabilities will include imaging of the 3D wave scattering using a binocular stereo camera system, as well as 3D device motion tracking using a newly acquired LED system. These observing systems will capture the 3D motion history of individual Buoys as well as resolve the 3D scattered wave field; thus resolving the constructive and destructive wave interference patterns produced by the array at high resolution. These data combined with the device motion tracking will provide necessary information for array design in order to balance array performance with the mitigation of far-field impacts. As a benchmark data set, these data will be an important resource for testing of models for wave/buoy interactions, buoy performance, and far-field effects on wave and current patterns due to the presence of arrays. Under the proposed project we will initiate

  6. Monte Carlo simulation of MLC-shaped TrueBeam electron fields benchmarked against measurement

    CERN Document Server

    Lloyd, Samantha AM; Zavgorodni, Sergei

    2014-01-01

    Modulated electron radiotherapy (MERT) and combined, modulated photon/electron radiotherapy (MPERT) have received increased research attention, having shown capacity for reduced low dose exposure to healthy tissue and comparable, if not improved, target coverage for a number of treatment sites. Accurate dose calculation tools are necessary for clinical treatment planning, and Monte Carlo (MC) is the gold standard for electron field simulation. With many clinics replacing older accelerators, MC source models of the new machines are needed for continued development, however, Varian has kept internal schematics of the TrueBeam confidential and electron phase-space sources have not been made available. TrueBeam electron fields are not substantially different from those generated by the Clinac 21EX, so we have modified the internal schematics of the Clinac 21EX to simulate TrueBeam electrons. BEAMnrc/DOSXYZnrc were used to simulate 5x5 and 20x20 cm$^2$ electron fields with MLC-shaped apertures. Secondary collimati...

  7. A wind energy benchmark for ABL modelling of a diurnal cycle with a nocturnal low-level jet: GABLS3 revisited

    Science.gov (United States)

    Sanz Rodrigo, J.; Churchfield, M.; Kosović, B.

    2016-09-01

    The third GEWEX Atmospheric Boundary Layer Studies (GABLS3) model intercomparison study, around the Cabauw met tower in the Netherlands, is revisited as a benchmark for wind energy atmospheric boundary layer (ABL) models. The case was originally developed by the boundary layer meteorology community, interested in analysing the performance of single-column and large-eddy simulation atmospheric models dealing with a diurnal cycle leading to the development of a nocturnal low-level jet. The case addresses fundamental questions related to the definition of the large-scale forcing, the interaction of the ABL with the surface and the evaluation of model results with observations. The characterization of mesoscale forcing for asynchronous microscale modelling of the ABL is discussed based on momentum budget analysis of WRF simulations. Then a single-column model is used to demonstrate the added value of incorporating different forcing mechanisms in microscale models. The simulations are evaluated in terms of wind energy quantities of interest.

  8. Benchmark Numerical Simulations of Viscoelastic Fluid Flows with an Efficient Integrated Lattice Boltzmann and Finite Volume Scheme

    Directory of Open Access Journals (Sweden)

    Shun Zou

    2015-02-01

    Full Text Available An efficient IBLF-dts scheme is proposed to integrate the bounce-back LBM and FVM scheme to solve the Navier-Stokes equations and the constitutive equation, respectively, for the simulation of viscoelastic fluid flows. In order to improve the efficiency, the bounce-back boundary treatment for LBM is introduced in to improve the grid mapping of LBM and FVM, and the two processes are also decoupled in different time scales according to the relaxation time of polymer and the time scale of solvent Newtonian effect. Critical numerical simulations have been carried out to validate the integrated scheme in various benchmark flows at vanishingly low Reynolds number with open source CFD toolkits. The results show that the numerical solution with IBLF-dts scheme agrees well with the exact solution and the numerical solution with FVM PISO scheme and the efficiency and scalability could be remarkably improved under equivalent configurations.

  9. On the energy conservation electrostatic PIC/MC simulating: benchmark and application to the radio frequency discharges

    CERN Document Server

    Hong-Yu, Wang; Peng, Sun; Ling-Bao, Kong

    2014-01-01

    We benchmark and analyze the error of energy conservation (EC) scheme for particle in cell/Monte-Carlo Couple (PIC/MCC) algorithms by a radio frequency discharging simulation. The plasma heating behaviors and electron distributing functions obtained by 1D simulation are analyzed. Both explicit and implicit algorithms are checked. The results showed that the EC scheme can eliminated the self-heating with wide grid spacing in both cases with a small reduction of the accuracies. In typical parameters, the EC implicit scheme has higher precision than EC explicit scheme. Some "numerical cooling" behaviors are observed and analyzed. Some other error are analyzed also. The analysis showed EC implicit scheme can be used to qualitative estimation of some discharge problems with much less computational resource costs without much loss of accuracies.

  10. 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

  11. Benchmarking the Higher Education Institutions in Egypt using Composite Index Model

    Directory of Open Access Journals (Sweden)

    Mohamed Rashad M El-Hefnawy

    2014-11-01

    Full Text Available Egypt has the largest and most significant higher education system in the Middle East and North Africa but it had been continuously facing serious and accumulated challenges. The Higher Education Institutions in Egypt are undergoing important changes involving the development of performance, they are implementing strategies to enhance the overall performance of their universities using ICT, but still the gap between what is existing and what is supposed to be for the self-regulation and improvement processes is not entirely clear to face these challenges. The using of strategic comparative analysis model and tools to evaluate the current and future states will affect the overall performance of universities and shape new paradigms in development of Higher Education System (HES, several studies have investigated the evaluation of universities through the development and use of ranking and benchmark systems In this paper, we provide a model to construct unified Composite Index (CI based on a set of SMART indictors emulate the nature of higher education systems in Egypt. The outcomes of the proposed model aim to measure overall performance of universities and provide unified benchmarking method in this context. The model was discussed from theoretical and technical perspectives. Meanwhile, the research study was conducted with 40 professors from 19 renowned universities in Egypt as education domain experts.

  12. Chemistry in Disks. IV. Benchmarking gas-grain chemical models with surface reactions

    CERN Document Server

    Semenov, D; Wakelam, V; Dutrey, A; Chapillon, E; Guilloteau, St; Henning, Th; Launhardt, R; Pietu, V; Schreyer, K

    2010-01-01

    Abridged: We detail and benchmark two sophisticated chemical models developed by the Heidelberg and Bordeaux astrochemistry groups. The main goal of this study is to elaborate on a few well-described tests for state-of-the-art astrochemical codes covering a range of physical conditions and chemical processes, in particular those aimed at constraining current and future interferometric observations of protoplanetary disks. We consider three physical models: a cold molecular cloud core, a hot core, and an outer region of a T Tauri disk. Our chemical network (for both models) is based on the original gas-phase osu_03_2008 ratefile and includes gas-grain interactions and a set of surface reactions for the H-, O-, C-, S-, and N-bearing molecules. The benchmarking is performed with the increasing complexity of the considered processes: (1) the pure gas-phase chemistry, (2) the gas-phase chemistry with accretion and desorption, and (3) the full gas-grain model with surface reactions. Using atomic initial abundances ...

  13. The benchmark aeroelastic models program: Description and highlights of initial results

    Science.gov (United States)

    Bennett, Robert M.; Eckstrom, Clinton V.; Rivera, Jose A., Jr.; Dansberry, Bryan E.; Farmer, Moses G.; Durham, Michael H.

    1992-01-01

    An experimental effort was implemented in aeroelasticity called the Benchmark Models Program. The primary purpose of this program is to provide the necessary data to evaluate computational fluid dynamic codes for aeroelastic analysis. It also focuses on increasing the understanding of the physics of unsteady flows and providing data for empirical design. An overview is given of this program and some results obtained in the initial tests are highlighted. The tests that were completed include measurement of unsteady pressures during flutter of a rigid wing with an NACA 0012 airfoil section and dynamic response measurements of a flexible rectangular wing with a thick circular arc airfoil undergoing shock boundary layer oscillations.

  14. Finite Element Method Modeling of Sensible Heat Thermal Energy Storage with Innovative Concretes and Comparative Analysis with Literature Benchmarks

    Directory of Open Access Journals (Sweden)

    Claudio Ferone

    2014-08-01

    Full Text Available Efficient systems for high performance buildings are required to improve the integration of renewable energy sources and to reduce primary energy consumption from fossil fuels. This paper is focused on sensible heat thermal energy storage (SHTES systems using solid media and numerical simulation of their transient behavior using the finite element method (FEM. Unlike other papers in the literature, the numerical model and simulation approach has simultaneously taken into consideration various aspects: thermal properties at high temperature, the actual geometry of the repeated storage element and the actual storage cycle adopted. High-performance thermal storage materials from the literatures have been tested and used here as reference benchmarks. Other materials tested are lightweight concretes with recycled aggregates and a geopolymer concrete. Their thermal properties have been measured and used as inputs in the numerical model to preliminarily evaluate their application in thermal storage. The analysis carried out can also be used to optimize the storage system, in terms of thermal properties required to the storage material. The results showed a significant influence of the thermal properties on the performances of the storage elements. Simulation results have provided information for further scale-up from a single differential storage element to the entire module as a function of material thermal properties.

  15. Benchmark experiments for higher-order and full Stokes ice sheet models (ISMIP-HOM

    Directory of Open Access Journals (Sweden)

    F. Pattyn

    2008-02-01

    Full Text Available We present the results of the first ice sheet model intercomparison project for higher-order and full Stokes ice sheet models. These models are validated in a series of six benchmark experiments of which one has an analytical solution under simplifying assumptions. Five of the tests are diagnostic and one experiment is prognostic or time dependent, for both 2-D and 3-D geometries. The results show a good convergence of the different models even for high aspect ratios. A clear distinction can be made between higher-order models and those that solve the full system of equations. The latter show a significantly better agreement with each other as well as with analytical solutions, which demonstrates that they are hardly influenced by the used numerics.

  16. Comprehensive Benchmark Suite for Simulation of Particle Laden Flows Using the Discrete Element Method with Performance Profiles from the Multiphase Flow with Interface eXchanges (MFiX) Code

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Peiyuan [Univ. of Colorado, Boulder, CO (United States); Brown, Timothy [Univ. of Colorado, Boulder, CO (United States); Fullmer, William D. [Univ. of Colorado, Boulder, CO (United States); Hauser, Thomas [Univ. of Colorado, Boulder, CO (United States); Hrenya, Christine [Univ. of Colorado, Boulder, CO (United States); Grout, Ray [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sitaraman, Hariswaran [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-01-29

    Five benchmark problems are developed and simulated with the computational fluid dynamics and discrete element model code MFiX. The benchmark problems span dilute and dense regimes, consider statistically homogeneous and inhomogeneous (both clusters and bubbles) particle concentrations and a range of particle and fluid dynamic computational loads. Several variations of the benchmark problems are also discussed to extend the computational phase space to cover granular (particles only), bidisperse and heat transfer cases. A weak scaling analysis is performed for each benchmark problem and, in most cases, the scalability of the code appears reasonable up to approx. 103 cores. Profiling of the benchmark problems indicate that the most substantial computational time is being spent on particle-particle force calculations, drag force calculations and interpolating between discrete particle and continuum fields. Hardware performance analysis was also carried out showing significant Level 2 cache miss ratios and a rather low degree of vectorization. These results are intended to serve as a baseline for future developments to the code as well as a preliminary indicator of where to best focus performance optimizations.

  17. Internet based benchmarking

    DEFF Research Database (Denmark)

    Bogetoft, Peter; Nielsen, Kurt

    2005-01-01

    We discuss the design of interactive, internet based benchmarking using parametric (statistical) as well as nonparametric (DEA) models. The user receives benchmarks and improvement potentials. The user is also given the possibility to search different efficiency frontiers and hereby to explore al...... alternative improvement strategies. Implementations of both a parametric and a non-parametric model are presented....

  18. Gravity for Detecting Caves: Airborne and Terrestrial Simulations Based on a Comprehensive Karstic Cave Benchmark

    Science.gov (United States)

    Braitenberg, Carla; Sampietro, Daniele; Pivetta, Tommaso; Zuliani, David; Barbagallo, Alfio; Fabris, Paolo; Rossi, Lorenzo; Fabbri, Julius; Mansi, Ahmed Hamdi

    2016-04-01

    Underground caves bear a natural hazard due to their possible evolution into a sink hole. Mapping of all existing caves could be useful for general civil usages as natural deposits or tourism and sports. Natural caves exist globally and are typical in karst areas. We investigate the resolution power of modern gravity campaigns to systematically detect all void caves of a minimum size in a given area. Both aerogravity and terrestrial acquisitions are considered. Positioning of the gravity station is fastest with GNSS methods the performance of which is investigated. The estimates are based on a benchmark cave of which the geometry is known precisely through a laser-scan survey. The cave is the Grotta Gigante cave in NE Italy in the classic karst. The gravity acquisition is discussed, where heights have been acquired with dual-frequency geodetic GNSS receivers and Total Station. Height acquisitions with non-geodetic low-cost receivers are shown to be useful, although the error on the gravity field is larger. The cave produces a signal of -1.5 × 10-5 m/s2, with a clear elliptic geometry. We analyze feasibility of airborne gravity acquisitions for the purpose of systematically mapping void caves. It is found that observations from fixed wing aircraft cannot resolve the caves, but observations from slower and low-flying helicopters or drones do. In order to detect the presence of caves the size of the benchmark cave, systematic terrestrial acquisitions require a density of three stations on square 500 by 500 m2 tiles. The question has a large impact on civil and environmental purposes, since it will allow planning of urban development at a safe distance from subsurface caves. The survey shows that a systematic coverage of the karst would have the benefit to recover the position of all of the greater existing void caves.

  19. Groundwater flow with energy transport and water-ice phase change: Numerical simulations, benchmarks, and application to freezing in peat bogs

    Science.gov (United States)

    McKenzie, J.M.; Voss, C.I.; Siegel, D.I.

    2007-01-01

    In northern peatlands, subsurface ice formation is an important process that can control heat transport, groundwater flow, and biological activity. Temperature was measured over one and a half years in a vertical profile in the Red Lake Bog, Minnesota. To successfully simulate the transport of heat within the peat profile, the U.S. Geological Survey's SUTRA computer code was modified. The modified code simulates fully saturated, coupled porewater-energy transport, with freezing and melting porewater, and includes proportional heat capacity and thermal conductivity of water and ice, decreasing matrix permeability due to ice formation, and latent heat. The model is verified by correctly simulating the Lunardini analytical solution for ice formation in a porous medium with a mixed ice-water zone. The modified SUTRA model correctly simulates the temperature and ice distributions in the peat bog. Two possible benchmark problems for groundwater and energy transport with ice formation and melting are proposed that may be used by other researchers for code comparison. ?? 2006 Elsevier Ltd. All rights reserved.

  20. Comparison of Homogeneous and Heterogeneous CFD Fuel Models for Phase I of the IAEA CRP on HTR Uncertainties Benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Gerhard Strydom; Su-Jong Yoon

    2014-04-01

    Computational Fluid Dynamics (CFD) evaluation of homogeneous and heterogeneous fuel models was performed as part of the Phase I calculations of the International Atomic Energy Agency (IAEA) Coordinate Research Program (CRP) on High Temperature Reactor (HTR) Uncertainties in Modeling (UAM). This study was focused on the nominal localized stand-alone fuel thermal response, as defined in Ex. I-3 and I-4 of the HTR UAM. The aim of the stand-alone thermal unit-cell simulation is to isolate the effect of material and boundary input uncertainties on a very simplified problem, before propagation of these uncertainties are performed in subsequent coupled neutronics/thermal fluids phases on the benchmark. In many of the previous studies for high temperature gas cooled reactors, the volume-averaged homogeneous mixture model of a single fuel compact has been applied. In the homogeneous model, the Tristructural Isotropic (TRISO) fuel particles in the fuel compact were not modeled directly and an effective thermal conductivity was employed for the thermo-physical properties of the fuel compact. On the contrary, in the heterogeneous model, the uranium carbide (UCO), inner and outer pyrolytic carbon (IPyC/OPyC) and silicon carbide (SiC) layers of the TRISO fuel particles are explicitly modeled. The fuel compact is modeled as a heterogeneous mixture of TRISO fuel kernels embedded in H-451 matrix graphite. In this study, a steady-state and transient CFD simulations were performed with both homogeneous and heterogeneous models to compare the thermal characteristics. The nominal values of the input parameters are used for this CFD analysis. In a future study, the effects of input uncertainties in the material properties and boundary parameters will be investigated and reported.

  1. An Analysis of Step, Jt, and Pdf Format Translation Between Constraint-based Cad Systems with a Benchmark Model

    OpenAIRE

    McKenzie-Veal, Dillon

    2012-01-01

    This research was conducted to provide greater depth into the ability of STEP AP 203 Edition 2, JT, and 3D PDF to translate and preserve information while using a benchmark model. The benchmark model was designed based on four industry models and created natively in the five industry leading 3D CAD programs. The native CAD program models were translated using STEP, JT, and 3D PDF. Several criteria were analyzed along the paths of translation from one disparate CAD program to another. Along wi...

  2. New LHC Benchmarks for the CP-conserving Two-Higgs-Doublet Model

    CERN Document Server

    Haber, Howard E

    2015-01-01

    We introduce a strategy to study the parameter space of the general, CP-conserving, two-Higgs-doublet Model (2HDM) with a softly broken Z_2-symmetry by means of a new "hybrid" basis. In this basis the input parameters are the measured values of the mass of the observed Standard Model (SM)-like Higgs boson and its coupling strength to vector boson pairs, the mass of the second CP-even Higgs boson, the ratio of neutral Higgs vacuum expectation values, and three additional dimensionless parameters. Using the hybrid basis, we present numerical scans of the 2HDM parameter space where we survey available parameter regions and analyze model constraints. From these results, we define a number of benchmark scenarios that capture different aspects of non-standard Higgs phenomenology that are of interest for future LHC Higgs searches.

  3. Modelling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Casetti, E.; Vogt, W.G.; Mickle, M.H.

    1984-01-01

    This conference includes papers on the uses of supercomputers, multiprocessors, artificial intelligence and expert systems in various energy applications. Topics considered include knowledge-based expert systems for power engineering, a solar air conditioning laboratory computer system, multivariable control systems, the impact of power system disturbances on computer systems, simulating shared-memory parallel computers, real-time image processing with multiprocessors, and network modeling and simulation of greenhouse solar systems.

  4. Benchmark measurements and simulations of dose perturbations due to metallic spheres in proton beams

    Science.gov (United States)

    Newhauser, Wayne D.; Rechner, Laura; Mirkovic, Dragan; Yepes, Pablo; Koch, Nicholas C.; Titt, Uwe; Fontenot, Jonas D.; Zhang, Rui

    2014-01-01

    Monte Carlo simulations are increasingly used for dose calculations in proton therapy due to its inherent accuracy. However, dosimetric deviations have been found using Monte Carlo code when high density materials are present in the proton beam line. The purpose of this work was to quantify the magnitude of dose perturbation caused by metal objects. We did this by comparing measurements and Monte Carlo predictions of dose perturbations caused by the presence of small metal spheres in several clinical proton therapy beams as functions of proton beam range, spread-out Bragg peak width and drift space. Monte Carlo codes MCNPX, GEANT4 and Fast Dose Calculator (FDC) were used. Generally good agreement was found between measurements and Monte Carlo predictions, with the average difference within 5% and maximum difference within 17%. The modification of multiple Coulomb scattering model in MCNPX code yielded improvement in accuracy and provided the best overall agreement with measurements. Our results confirmed that Monte Carlo codes are well suited for predicting multiple Coulomb scattering in proton therapy beams when short drift spaces are involved. PMID:25147474

  5. Modelling Hydraulic and Thermal Responses in a Benchmark for Deep Geothermal Heat Production

    Science.gov (United States)

    Holzbecher, E.; Oberdorfer, P.

    2012-04-01

    Geothermal heat production from deep reservoirs (5000-7000 m) is currently examined within the collaborative research program "Geothermal Energy and High-Performance Drilling" (gebo), funded by the Ministry of Science and Culture of Lower Saxony (Germany) and Baker Hughes. The projects concern exploration and characterization of geothermal reservoirs as well as production. They are gathered in the four major topic fields: geosystem, drilling, materials, technical system. We present modelling of a benchmark set-up concerning the geothermal production itself. The benchmark model "Horstberg" was originally created by J. Löhken and is based on geological data, concerning the Horstberg site in Lower Saxony. The model region consists of a cube with a side length of 5 km, in which 13 geological layers are included. A fault zone splits the region into two parts with shifted layering. A well is implemented, reaching from the top to an optional depth crossing all layers including the fault zone. The original geological model was rebuilt and improved in COMSOL Multiphysics Version 4.2a. The heterogeneous and detailed configuration makes the model interesting for benchmarking hydrogeological and geothermal applications. It is possible to inject and pump at any level in the well and to study the hydraulic and thermal responses of the system. The hydraulic and thermal parameters can be varied, and groundwater flow can be introduced. Moreover, it is also possible to examine structural mechanical responses to changes in the stress field (which is not further examined here). The main purpose of the presented study is to examine the dynamical flow characteristics of a hydraulic high conductive zone (Detfurth) in connection to a high conductive fault. One example is the fluid injection in the Detfurth zone and production in the fault. The high conductive domains can provide a hydraulic connection between the well screens and the initiated flow circuit could be used for geothermal

  6. How to Use Benchmark and Cross-section Studies to Improve Data Libraries and Models

    Science.gov (United States)

    Wagner, V.; Suchopár, M.; Vrzalová, J.; Chudoba, P.; Svoboda, O.; Tichý, P.; Krása, A.; Majerle, M.; Kugler, A.; Adam, J.; Baldin, A.; Furman, W.; Kadykov, M.; Solnyshkin, A.; Tsoupko-Sitnikov, S.; Tyutyunikov, S.; Vladimirovna, N.; Závorka, L.

    2016-06-01

    Improvements of the Monte Carlo transport codes and cross-section libraries are very important steps towards usage of the accelerator-driven transmutation systems. We have conducted a lot of benchmark experiments with different set-ups consisting of lead, natural uranium and moderator irradiated by relativistic protons and deuterons within framework of the collaboration “Energy and Transmutation of Radioactive Waste”. Unfortunately, the knowledge of the total or partial cross-sections of important reactions is insufficient. Due to this reason we have started extensive studies of different reaction cross-sections. We measure cross-sections of important neutron reactions by means of the quasi-monoenergetic neutron sources based on the cyclotrons at Nuclear Physics Institute in Řež and at The Svedberg Laboratory in Uppsala. Measurements of partial cross-sections of relativistic deuteron reactions were the second direction of our studies. The new results obtained during last years will be shown. Possible use of these data for improvement of libraries, models and benchmark studies will be discussed.

  7. Benchmarking Defmod, an open source FEM code for modeling episodic fault rupture

    Science.gov (United States)

    Meng, Chunfang

    2017-03-01

    We present Defmod, an open source (linear) finite element code that enables us to efficiently model the crustal deformation due to (quasi-)static and dynamic loadings, poroelastic flow, viscoelastic flow and frictional fault slip. Ali (2015) provides the original code introducing an implicit solver for (quasi-)static problem, and an explicit solver for dynamic problem. The fault constraint is implemented via Lagrange Multiplier. Meng (2015) combines these two solvers into a hybrid solver that uses failure criteria and friction laws to adaptively switch between the (quasi-)static state and dynamic state. The code is capable of modeling episodic fault rupture driven by quasi-static loadings, e.g. due to reservoir fluid withdraw or injection. Here, we focus on benchmarking the Defmod results against some establish results.

  8. An integer programming model and benchmark suite for liner shipping network design

    DEFF Research Database (Denmark)

    Løfstedt, Berit; Alvarez, Jose Fernando; Plum, Christian Edinger Munk

    along with a rich integer programming model based on the services, that constitute the fixed schedule of a liner shipping company. The model may be relaxed as well as decomposed. The design of a benchmark suite of data instances to reflect the business structure of a global liner shipping network......Maritime transportation is accountable for 2.7% of the worlds CO2 emissions and the liner shipping industry is committed to a slow steaming policy to provide low cost and environmentally conscious global transport of goods without compromising the level of service. The potential for making cost...... effective and energy efficient liner shipping networks using operations research is huge and neglected. The implementation of logistic planning tools based upon operations research has enhanced performance of both airlines, railways and general transportation companies, but within the field of liner...

  9. Benchmarking of a 1D Scrape-off layer code SOLF1D with SOLPS and its use in modelling long-legged divertors

    CERN Document Server

    Havlickova, E; Subba, F; Coster, D; Wischmeier, M; Fishpool, G

    2013-01-01

    A 1D code modelling SOL transport parallel to the magnetic field (SOLF1D) is benchmarked with 2D simulations of MAST-U SOL performed via the SOLPS code for two different collisionalities. Based on this comparison, SOLF1D is then used to model the effects of divertor leg stretching in 1D, in support of the planned Super-X divertor on MAST. The aim is to separate magnetic flux expansion from volumetric power losses due to recycling neutrals by stretching the divertor leg either vertically or radially.

  10. Benchmark 1 - Failure Prediction after Cup Drawing, Reverse Redrawing and Expansion Part A: Benchmark Description

    Science.gov (United States)

    Watson, Martin; Dick, Robert; Huang, Y. Helen; Lockley, Andrew; Cardoso, Rui; Santos, Abel

    2016-08-01

    This Benchmark is designed to predict the fracture of a food can after drawing, reverse redrawing and expansion. The aim is to assess different sheet metal forming difficulties such as plastic anisotropic earing and failure models (strain and stress based Forming Limit Diagrams) under complex nonlinear strain paths. To study these effects, two distinct materials, TH330 steel (unstoved) and AA5352 aluminum alloy are considered in this Benchmark. Problem description, material properties, and simulation reports with experimental data are summarized.

  11. Comparison of different numerical models using a two-dimensional density-driven benchmark of a freshwater lens

    Science.gov (United States)

    Stoeckl, L.; Walther, M.; Schneider, A.; Yang, J.; Gaj, M.; Graf, T.

    2013-12-01

    The physical experiment of Stoeckl and Houben (2012)* was taken as a benchmark to compare results of calculations by several finite volume and finite element programs. In the experiment, an acrylic glass box was used to simulate a cross section of an infinite strip island. Degassed salt water (density 1021 kg m-3) was injected, saturating the sand from bottom to top. Fluorescent tracer dyes (uranine, eosine and indigotine) were used to mark infiltrating fresh water (density 997 kg m-3) from the top. While freshwater constantly infiltrated, saltwater was displaced and a freshwater lens started to develop until reaching equilibrium. The experiment was recorded and analyzed using fast motion mode. The numerical groundwater flow models used for comparison are Feflow, Spring, OpenGeoSys, d3f and HydroGeoSphere. All programs are capable to solve the partial differential equations of coupled flow and transport. To ensure highest level of comparison, the setups are defined as similar as possible: identical temporal and spatial resolutions are applied to all models (triangular grid with 14,432 elements and constant time steps of 8.64 s); furthermore, the same boundary conditions and parameters are used; finally, the output of each model is converted into the same format and post-processed in the open-source program ParaView. Transient as well as steady state flow fields and concentration distributions are compared. Capabilities of the different models are described, showing differences, limitations and advantages. The results show, that all models are capable to represent the benchmark to a high degree. Still, differences are observed, even by keeping the models as similar as possible. Some deviations may be explained by omitted processes, which cannot be represented in certain models, whereas other deviations may be explained by program-specific differences in solving the partial differential equations. * Stoeckl, L., Houben, G. (2012): Flow dynamics and age stratification

  12. Financial Benchmarking

    OpenAIRE

    2012-01-01

    This bachelor's thesis is focused on financial benchmarking of TULIPA PRAHA s.r.o. The aim of this work is to evaluate financial situation of the company, identify its strengths and weaknesses and to find out how efficient is the performance of this company in comparison with top companies within the same field by using INFA benchmarking diagnostic system of financial indicators. The theoretical part includes the characteristic of financial analysis, which financial benchmarking is based on a...

  13. Validation of simulation models

    DEFF Research Database (Denmark)

    Rehman, Muniza; Pedersen, Stig Andur

    2012-01-01

    of models with regards to their purpose, character, field of application and time dimension inherently calls for a similar diversity in validation approaches. A classification of models in terms of the mentioned elements is presented and used to shed light on possible types of validation leading...... of models has been somewhat narrow-minded reducing the notion of validation to establishment of truth. This article puts forward the diversity in applications of simulation models that demands a corresponding diversity in the notion of validation....

  14. Building America Top Innovations 2012: House Simulation Protocols (the Building America Benchmark)

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2013-01-01

    This Building America Top Innovations profile describes the DOE-sponsored House Simulation Protocols, which have helped ensure consistent and accurate energy-efficiency assessments for tens of thousands of new and retrofit homes supported by the Building America program.

  15. Experimental unsteady pressures at flutter on the Supercritical Wing Benchmark Model

    Science.gov (United States)

    Dansberry, Bryan E.; Durham, Michael H.; Bennett, Robert M.; Rivera, Jose A.; Silva, Walter A.; Wieseman, Carol D.; Turnock, David L.

    1993-01-01

    This paper describes selected results from the flutter testing of the Supercritical Wing (SW) model. This model is a rigid semispan wing having a rectangular planform and a supercritical airfoil shape. The model was flutter tested in the Langley Transonic Dynamics Tunnel (TDT) as part of the Benchmark Models Program, a multi-year wind tunnel activity currently being conducted by the Structural Dynamics Division of NASA Langley Research Center. The primary objective of this program is to assist in the development and evaluation of aeroelastic computational fluid dynamics codes. The SW is the second of a series of three similar models which are designed to be flutter tested in the TDT on a flexible mount known as the Pitch and Plunge Apparatus. Data sets acquired with these models, including simultaneous unsteady surface pressures and model response data, are meant to be used for correlation with analytical codes. Presented in this report are experimental flutter boundaries and corresponding steady and unsteady pressure distribution data acquired over two model chords located at the 60 and 95 percent span stations.

  16. Three-dimensional benchmark for variable-density flow and transport simulation: matching semi-analytic stability modes for steady unstable convection in an inclined porous box

    Science.gov (United States)

    Voss, Clifford I.; Simmons, Craig T.; Robinson, Neville I.

    2010-01-01

    This benchmark for three-dimensional (3D) numerical simulators of variable-density groundwater flow and solute or energy transport consists of matching simulation results with the semi-analytical solution for the transition from one steady-state convective mode to another in a porous box. Previous experimental and analytical studies of natural convective flow in an inclined porous layer have shown that there are a variety of convective modes possible depending on system parameters, geometry and inclination. In particular, there is a well-defined transition from the helicoidal mode consisting of downslope longitudinal rolls superimposed upon an upslope unicellular roll to a mode consisting of purely an upslope unicellular roll. Three-dimensional benchmarks for variable-density simulators are currently (2009) lacking and comparison of simulation results with this transition locus provides an unambiguous means to test the ability of such simulators to represent steady-state unstable 3D variable-density physics.

  17. Variational tensor network renormalization in imaginary time: Benchmark results in the Hubbard model at finite temperature

    Science.gov (United States)

    Czarnik, Piotr; Rams, Marek M.; Dziarmaga, Jacek

    2016-12-01

    A Gibbs operator e-β H for a two-dimensional (2D) lattice system with a Hamiltonian H can be represented by a 3D tensor network, with the third dimension being the imaginary time (inverse temperature) β . Coarse graining the network along β results in a 2D projected entangled-pair operator (PEPO) with a finite bond dimension. The coarse graining is performed by a tree tensor network of isometries. They are optimized variationally to maximize the accuracy of the PEPO as a representation of the 2D thermal state e-β H. The algorithm is applied to the two-dimensional Hubbard model on an infinite square lattice. Benchmark results at finite temperature are obtained that are consistent with the best cluster dynamical mean-field theory and power-series expansion in the regime of parameters where they yield mutually consistent results.

  18. Creating a benchmark of vertical axis wind turbines in dynamic stall for validating numerical models

    DEFF Research Database (Denmark)

    Castelein, D.; Ragni, D.; Tescione, G.;

    2015-01-01

    -based Reynolds number of 1.6e5 and 0.8e5. At both TSR, the velocity fields are presented in the mid (symmetry) plane of the blade for eight azimuthal positions. The velocity fields are directly derived from PIV, while the loads are obtained through an integral approach presented by Noca et...... al. The experimental data of the velocity fields around the airfoil and the loads on the blade are used for numerical validation. The aim of evaluating the two different TSR is identifying the effect of Dynamic Stall (DS), which is not present at the higher TSR, while dominant at the lower. The DS...... phenomenon is numerically very hard to model, so a solid benchmark for a VAWT in DS is of great interest. The aim of the paper is to present the experimental flow fields, and the validated loads on the blades for both TSR....

  19. Benchmarking inverse statistical approaches for protein structure and design with exactly solvable models

    CERN Document Server

    Jacquin, Hugo; Shakhnovich, Eugene; Cocco, Simona; Monasson, Rémi

    2016-01-01

    Inverse statistical approaches to determine protein structure and function from Multiple Sequence Alignments (MSA) are emerging as powerful tools in computational biology. However the underlying assumptions of the relationship between the inferred effective Potts Hamiltonian and real protein structure and energetics remain untested so far. Here we use lattice protein model (LP) to benchmark those inverse statistical approaches. We build MSA of highly stable sequences in target LP structures, and infer the effective pairwise Potts Hamiltonians from those MSA. We find that inferred Potts Hamiltonians reproduce many important aspects of 'true' LP structures and energetics. Careful analysis reveals that effective pairwise couplings in inferred Potts Hamiltonians depend not only on the energetics of the native structure but also on competing folds; in particular, the coupling values reflect both positive design (stabilization of native conformation) and negative design (destabilization of competing folds). In addi...

  20. Mathematical modeling and modification of an activated sludge benchmark process evaluated by multiple performance criteria

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wenliang; Yao, Chonghua [East China University of Science and Technology, Shanghai (China); Lu, Xiwu [Southeast University, Nanjing (China)

    2014-08-15

    Optimal modification of an activated sludge process (ASP) evaluated by multiple performance criteria was studied. A benchmark process in BSM1 was taken as a target process. Four indexes of percentage of effluent violation (PEV), energy consumption (OCI), total volume of tanks (TV) and total suspended solid in tank5 (TSSa5), were criteria and eleven process parameters were decision variables, making up the multiple criteria optimization model, which was solved by non-dominated sorting genetic algorithm II (NSGA-II) in MATLAB. Pareto solutions were obtained; one solution (opt1) was selected based on the authors' decision for a further analysis. Results show that the process with opt1 strategy exhibits much better performance of PEV and OCI than with the default, being improved by 74.17% and 9.97% specifically under dry influent and without control. These results indicated that the multiple criterion optimization method is very useful for modification of an ASP.

  1. Rheological benchmark of silicone oils used for analog modeling of short- and long-term lithospheric deformation

    Science.gov (United States)

    Rudolf, Michael; Boutelier, David; Rosenau, Matthias; Schreurs, Guido; Oncken, Onno

    2016-08-01

    Analog models of tectonic processes at various scales commonly use silicone polymers to simulate viscous flow in the lower crust and mantle. To achieve dynamic similarity with the natural prototype and to improve comparability between analog models, better knowledge of the rheology of commonly used silicones is required. In this study, we present a rheological benchmark of silicones used in various laboratories. Rheometric tests, including rotational and oscillatory tests, were performed and the viscoelastic behavior of silicone is quantitatively described. We found that silicone oils show a transition from Newtonian viscous to power-law, shear thinning behavior around shear rates of 10- 2 to 10- 1 s- 1. The viscosity of chemically similar silicones varied between 2 and 3 × 104 Pa s. Maxwell relaxation times are about 0.1-0.2 s. Such a behavior is able to mimic slow to fast deformation mechanisms in the ductile regime, such as diffusion and dislocation creep as well as viscoelastic relaxation processes. Temperature and aging effects are verified, but can be considered minor with respect to the uncertainty in rheological properties in the natural prototype. Nevertheless, to assure comparability between models and proper scaling the exact properties and conditions should be reported.

  2. Benchmarking of Heavy Ion Transport Codes

    Energy Technology Data Exchange (ETDEWEB)

    Remec, Igor [ORNL; Ronningen, Reginald M. [Michigan State University, East Lansing; Heilbronn, Lawrence [University of Tennessee, Knoxville (UTK)

    2011-01-01

    Accurate prediction of radiation fields generated by heavy ion interactions is important in medical applications, space missions, and in designing and operation of rare isotope research facilities. In recent years, several well-established computer codes in widespread use for particle and radiation transport calculations have been equipped with the capability to simulate heavy ion transport and interactions. To assess and validate these capabilities, we performed simulations of a series of benchmark-quality heavy ion experiments with the computer codes FLUKA, MARS15, MCNPX, and PHITS. We focus on the comparisons of secondary neutron production. Results are encouraging; however, further improvements in models and codes and additional benchmarking are required.

  3. Benchmark selection

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Tvede, Mich

    2002-01-01

    Within a production theoretic framework, this paper considers an axiomatic approach to benchmark selection. It is shown that two simple and weak axioms; efficiency and comprehensive monotonicity characterize a natural family of benchmarks which typically becomes unique. Further axioms are added...

  4. Parareal in time 3D numerical solver for the LWR Benchmark neutron diffusion transient model

    Energy Technology Data Exchange (ETDEWEB)

    Baudron, Anne-Marie, E-mail: anne-marie.baudron@cea.fr [Laboratoire de Recherche Conventionné MANON, CEA/DEN/DANS/DM2S and UPMC-CNRS/LJLL (France); CEA-DRN/DMT/SERMA, CEN-Saclay, 91191 Gif sur Yvette Cedex (France); Lautard, Jean-Jacques, E-mail: jean-jacques.lautard@cea.fr [Laboratoire de Recherche Conventionné MANON, CEA/DEN/DANS/DM2S and UPMC-CNRS/LJLL (France); CEA-DRN/DMT/SERMA, CEN-Saclay, 91191 Gif sur Yvette Cedex (France); Maday, Yvon, E-mail: maday@ann.jussieu.fr [Sorbonne Universités, UPMC Univ Paris 06, UMR 7598, Laboratoire Jacques-Louis Lions and Institut Universitaire de France, F-75005, Paris (France); Laboratoire de Recherche Conventionné MANON, CEA/DEN/DANS/DM2S and UPMC-CNRS/LJLL (France); Brown Univ, Division of Applied Maths, Providence, RI (United States); Riahi, Mohamed Kamel, E-mail: riahi@cmap.polytechnique.fr [Laboratoire de Recherche Conventionné MANON, CEA/DEN/DANS/DM2S and UPMC-CNRS/LJLL (France); CMAP, Inria-Saclay and X-Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Salomon, Julien, E-mail: salomon@ceremade.dauphine.fr [CEREMADE, Univ Paris-Dauphine, Pl. du Mal. de Lattre de Tassigny, F-75016, Paris (France)

    2014-12-15

    In this paper we present a time-parallel algorithm for the 3D neutrons calculation of a transient model in a nuclear reactor core. The neutrons calculation consists in numerically solving the time dependent diffusion approximation equation, which is a simplified transport equation. The numerical resolution is done with finite elements method based on a tetrahedral meshing of the computational domain, representing the reactor core, and time discretization is achieved using a θ-scheme. The transient model presents moving control rods during the time of the reaction. Therefore, cross-sections (piecewise constants) are taken into account by interpolations with respect to the velocity of the control rods. The parallelism across the time is achieved by an adequate use of the parareal in time algorithm to the handled problem. This parallel method is a predictor corrector scheme that iteratively combines the use of two kinds of numerical propagators, one coarse and one fine. Our method is made efficient by means of a coarse solver defined with large time step and fixed position control rods model, while the fine propagator is assumed to be a high order numerical approximation of the full model. The parallel implementation of our method provides a good scalability of the algorithm. Numerical results show the efficiency of the parareal method on large light water reactor transient model corresponding to the Langenbuch–Maurer–Werner benchmark.

  5. Benchmarking monthly homogenization algorithms

    Directory of Open Access Journals (Sweden)

    V. K. C. Venema

    2011-08-01

    Full Text Available The COST (European Cooperation in Science and Technology Action ES0601: Advances in homogenization methods of climate series: an integrated approach (HOME has executed a blind intercomparison and validation study for monthly homogenization algorithms. Time series of monthly temperature and precipitation were evaluated because of their importance for climate studies and because they represent two important types of statistics (additive and multiplicative. The algorithms were validated against a realistic benchmark dataset. The benchmark contains real inhomogeneous data as well as simulated data with inserted inhomogeneities. Random break-type inhomogeneities were added to the simulated datasets modeled as a Poisson process with normally distributed breakpoint sizes. To approximate real world conditions, breaks were introduced that occur simultaneously in multiple station series within a simulated network of station data. The simulated time series also contained outliers, missing data periods and local station trends. Further, a stochastic nonlinear global (network-wide trend was added.

    Participants provided 25 separate homogenized contributions as part of the blind study as well as 22 additional solutions submitted after the details of the imposed inhomogeneities were revealed. These homogenized datasets were assessed by a number of performance metrics including (i the centered root mean square error relative to the true homogeneous value at various averaging scales, (ii the error in linear trend estimates and (iii traditional contingency skill scores. The metrics were computed both using the individual station series as well as the network average regional series. The performance of the contributions depends significantly on the error metric considered. Contingency scores by themselves are not very informative. Although relative homogenization algorithms typically improve the homogeneity of temperature data, only the best ones improve

  6. Benchmarking and Regulation

    DEFF Research Database (Denmark)

    Agrell, Per J.; Bogetoft, Peter

    . The application of benchmarking in regulation, however, requires specific steps in terms of data validation, model specification and outlier detection that are not systematically documented in open publications, leading to discussions about regulatory stability and economic feasibility of these techniques...

  7. Application of two-dimensional infrared spectroscopy to benchmark models for the amide I band of proteins

    NARCIS (Netherlands)

    Bondarenko, Anna S.; Jansen, Thomas L. C.

    2015-01-01

    In this paper, we present a novel benchmarking method for validating the modelling of vibrational spectra for the amide I region of proteins. We use the linear absorption spectra and two-dimensional infrared spectra of four experimentally well-studied proteins as a reference and test nine combinatio

  8. CFD Analysis of a Void Distribution Benchmark of the NUPEC PSBT Tests: Model Calibration and Influence of Turbulence Modelling

    Directory of Open Access Journals (Sweden)

    E. Krepper

    2012-01-01

    Full Text Available The paper presents CFD calculations of the void distribution tests of the PSBT benchmark using ANSYS CFX-12.1. First, relevant aspects of the implemented wall boiling model are reviewed highlighting the uncertainties in several model parameters. It is then shown that the measured cross-sectionally averaged values can be reproduced well with a single set of calibrated model parameters for different test cases. For the reproduction of patterns of void distribution cross-sections, attention has to be focussed on the modelling of turbulence in the narrow channel. Only a turbulence model with the capability to resolve turbulent secondary flows is able to reproduce at least qualitatively the observed void distribution patterns.

  9. Antibiotic reimbursement in a model delinked from sales: a benchmark-based worldwide approach.

    Science.gov (United States)

    Rex, John H; Outterson, Kevin

    2016-04-01

    Despite the life-saving ability of antibiotics and their importance as a key enabler of all of modern health care, their effectiveness is now threatened by a rising tide of resistance. Unfortunately, the antibiotic pipeline does not match health needs because of challenges in discovery and development, as well as the poor economics of antibiotics. Discovery and development are being addressed by a range of public-private partnerships; however, correcting the poor economics of antibiotics will need an overhaul of the present business model on a worldwide scale. Discussions are now converging on delinking reward from antibiotic sales through prizes, milestone payments, or insurance-like models in which innovation is rewarded with a fixed series of payments of a predictable size. Rewarding all drugs with the same payments could create perverse incentives to produce drugs that provide the least possible innovation. Thus, we propose a payment model using a graded array of benchmarked rewards designed to encourage the development of antibiotics with the greatest societal value, together with appropriate worldwide access to antibiotics to maximise human health.

  10. Terahertz vibrations of crystalline acyclic and cyclic diglycine: benchmarks for London force correction models.

    Science.gov (United States)

    Juliano, Thomas R; Korter, Timothy M

    2013-10-10

    Terahertz spectroscopy provides direct information concerning weak intermolecular forces in crystalline molecular solids and therefore acts as an excellent method for calibrating and evaluating computational models for noncovalent interactions. In this study, the low-frequency vibrations of two dipeptides were compared, acyclic diglycine and cyclic diglycine, as benchmark systems for gauging the performance of semiempirical London force correction approaches. The diglycine samples were investigated using pulsed terahertz spectroscopy from 10 to 100 cm(-1) and then analyzed using solid-state density functional theory (DFT) augmented with existing London force corrections, as well as a new parametrization (DFT-DX) based on known experimental values. The two diglycine molecules provide a useful test for the applied models given their similarities, but more importantly the differences in the intermolecular forces displayed by each. It was found that all of the considered London force correction models were able to generate diglycine crystal structures of similar accuracy, but considerable variation occurred in their abilities to predict terahertz frequency vibrations. The DFT-DX parametrization was particularly successful in this investigation and shows promise for the improved analysis of low-frequency spectra.

  11. Wake modeling and simulation

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Madsen Aagaard, Helge; Larsen, Torben J.;

    , have the potential to include also mutual wake interaction phenomenons. The basic conjecture behind the dynamic wake meandering (DWM) model is that wake transportation in the atmospheric boundary layer is driven by the large scale lateral- and vertical turbulence components. Based on this conjecture...... and trailed vorticity, has been approached by a simple semi-empirical model essentially based on an eddy viscosity philosophy. Contrary to previous attempts to model wake loading, the DWM approach opens for a unifying description in the sense that turbine power- and load aspects can be treated simultaneously...... methodology has been implemented in the aeroelastic code HAWC2, and example simulations of wake situations, from the small Tjæreborg wind farm, have been performed showing satisfactory agreement between predictions and measurements...

  12. Delay modeling in logic simulation

    Energy Technology Data Exchange (ETDEWEB)

    Acken, J. M.; Goldstein, L. H.

    1980-01-01

    As digital integrated circuit size and complexity increases, the need for accurate and efficient computer simulation increases. Logic simulators such as SALOGS (SAndia LOGic Simulator), which utilize transition states in addition to the normal stable states, provide more accurate analysis than is possible with traditional logic simulators. Furthermore, the computational complexity of this analysis is far lower than that of circuit simulation such as SPICE. An eight-value logic simulation environment allows the use of accurate delay models that incorporate both element response and transition times. Thus, timing simulation with an accuracy approaching that of circuit simulation can be accomplished with an efficiency comparable to that of logic simulation. 4 figures.

  13. Thermochemistry of organic reactions in microporous oxides by atomistic simulations: benchmarking against periodic B3LYP.

    Science.gov (United States)

    Bleken, Francesca; Svelle, Stian; Lillerud, Karl Petter; Olsbye, Unni; Arstad, Bjørnar; Swang, Ole

    2010-07-15

    The methylation of ethene by methyl chloride and methanol in the microporous materials SAPO-34 and SSZ-13 has been studied using different periodic atomistic modeling approaches based on density functional theory. The RPBE functional, which earlier has been used successfully in studies of surface reactions on metals, fails to yield a qualitatively correct description of the transition states under study. Employing B3LYP as functional gives results in line with experimental data: (1) Methanol is adsorbed more strongly than methyl chloride to the acid site. (2) The activation energies for the methylation of ethene are slightly lower for SSZ-13. Furthermore, the B3LYP activation energies are lower for methyl chloride than for methanol.

  14. Benchmarking a multiresolution discontinuous Galerkin shallow water model: Implications for computational hydraulics

    Science.gov (United States)

    Caviedes-Voullième, Daniel; Kesserwani, Georges

    2015-12-01

    Numerical modelling of wide ranges of different physical scales, which are involved in Shallow Water (SW) problems, has been a key challenge in computational hydraulics. Adaptive meshing techniques have been commonly coupled with numerical methods in an attempt to address this challenge. The combination of MultiWavelets (MW) with the Runge-Kutta Discontinuous Galerkin (RKDG) method offers a new philosophy to readily achieve mesh adaptivity driven by the local variability of the numerical solution, and without requiring more than one threshold value set by the user. However, the practical merits and implications of the MWRKDG, in terms of how far it contributes to address the key challenge above, are yet to be explored. This work systematically explores this, through the verification and validation of the MWRKDG for selected steady and transient benchmark tests, which involves the features of real SW problems. Our findings reveal a practical promise of the SW-MWRKDG solver, in terms of efficient and accurate mesh-adaptivity, but also suggest further improvement in the SW-RKDG reference scheme to better intertwine with, and harness the prowess of, the MW-based adaptivity.

  15. Proton Exchange Membrane Fuel Cell Engineering Model Powerplant. Test Report: Benchmark Tests in Three Spatial Orientations

    Science.gov (United States)

    Loyselle, Patricia; Prokopius, Kevin

    2011-01-01

    Proton exchange membrane (PEM) fuel cell technology is the leading candidate to replace the aging alkaline fuel cell technology, currently used on the Shuttle, for future space missions. This test effort marks the final phase of a 5-yr development program that began under the Second Generation Reusable Launch Vehicle (RLV) Program, transitioned into the Next Generation Launch Technologies (NGLT) Program, and continued under Constellation Systems in the Exploration Technology Development Program. Initially, the engineering model (EM) powerplant was evaluated with respect to its performance as compared to acceptance tests carried out at the manufacturer. This was to determine the sensitivity of the powerplant performance to changes in test environment. In addition, a series of tests were performed with the powerplant in the original standard orientation. This report details the continuing EM benchmark test results in three spatial orientations as well as extended duration testing in the mission profile test. The results from these tests verify the applicability of PEM fuel cells for future NASA missions. The specifics of these different tests are described in the following sections.

  16. Including the effects of filamentous bulking sludge during the simulation of wastewater treatment plants using a risk assessment model

    DEFF Research Database (Denmark)

    Flores Alsina, Xavier; Comas, J.; Rodriquez-Roda, I.

    2009-01-01

    The main objective of this paper is to demonstrate how including the occurrence of filamentous bulking sludge in a secondary clarifier model will affect the predicted process performance during the simulation of WWTPs. The IWA Benchmark Simulation Model No. 2 (BSM2) is hereby used as a simulation...

  17. The MCNP6 Analytic Criticality Benchmark Suite

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Forrest B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Monte Carlo Codes Group

    2016-06-16

    Analytical benchmarks provide an invaluable tool for verifying computer codes used to simulate neutron transport. Several collections of analytical benchmark problems [1-4] are used routinely in the verification of production Monte Carlo codes such as MCNP® [5,6]. Verification of a computer code is a necessary prerequisite to the more complex validation process. The verification process confirms that a code performs its intended functions correctly. The validation process involves determining the absolute accuracy of code results vs. nature. In typical validations, results are computed for a set of benchmark experiments using a particular methodology (code, cross-section data with uncertainties, and modeling) and compared to the measured results from the set of benchmark experiments. The validation process determines bias, bias uncertainty, and possibly additional margins. Verification is generally performed by the code developers, while validation is generally performed by code users for a particular application space. The VERIFICATION_KEFF suite of criticality problems [1,2] was originally a set of 75 criticality problems found in the literature for which exact analytical solutions are available. Even though the spatial and energy detail is necessarily limited in analytical benchmarks, typically to a few regions or energy groups, the exact solutions obtained can be used to verify that the basic algorithms, mathematics, and methods used in complex production codes perform correctly. The present work has focused on revisiting this benchmark suite. A thorough review of the problems resulted in discarding some of them as not suitable for MCNP benchmarking. For the remaining problems, many of them were reformulated to permit execution in either multigroup mode or in the normal continuous-energy mode for MCNP. Execution of the benchmarks in continuous-energy mode provides a significant advance to MCNP verification methods.

  18. Benchmarking: applications to transfusion medicine.

    Science.gov (United States)

    Apelseth, Torunn Oveland; Molnar, Laura; Arnold, Emmy; Heddle, Nancy M

    2012-10-01

    Benchmarking is as a structured continuous collaborative process in which comparisons for selected indicators are used to identify factors that, when implemented, will improve transfusion practices. This study aimed to identify transfusion medicine studies reporting on benchmarking, summarize the benchmarking approaches used, and identify important considerations to move the concept of benchmarking forward in the field of transfusion medicine. A systematic review of published literature was performed to identify transfusion medicine-related studies that compared at least 2 separate institutions or regions with the intention of benchmarking focusing on 4 areas: blood utilization, safety, operational aspects, and blood donation. Forty-five studies were included: blood utilization (n = 35), safety (n = 5), operational aspects of transfusion medicine (n = 5), and blood donation (n = 0). Based on predefined criteria, 7 publications were classified as benchmarking, 2 as trending, and 36 as single-event studies. Three models of benchmarking are described: (1) a regional benchmarking program that collects and links relevant data from existing electronic sources, (2) a sentinel site model where data from a limited number of sites are collected, and (3) an institutional-initiated model where a site identifies indicators of interest and approaches other institutions. Benchmarking approaches are needed in the field of transfusion medicine. Major challenges include defining best practices and developing cost-effective methods of data collection. For those interested in initiating a benchmarking program, the sentinel site model may be most effective and sustainable as a starting point, although the regional model would be the ideal goal.

  19. Shielding Integral Benchmark Archive and Database (SINBAD)

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, Bernadette Lugue [ORNL; Grove, Robert E [ORNL; Kodeli, I. [International Atomic Energy Agency (IAEA); Sartori, Enrico [ORNL; Gulliford, J. [OECD Nuclear Energy Agency

    2011-01-01

    The Shielding Integral Benchmark Archive and Database (SINBAD) collection of benchmarks was initiated in the early 1990 s. SINBAD is an international collaboration between the Organization for Economic Cooperation and Development s Nuclear Energy Agency Data Bank (OECD/NEADB) and the Radiation Safety Information Computational Center (RSICC) at Oak Ridge National Laboratory (ORNL). SINBAD is a major attempt to compile experiments and corresponding computational models with the goal of preserving institutional knowledge and expertise that need to be handed down to future scientists. SINBAD is also a learning tool for university students and scientists who need to design experiments or gain expertise in modeling and simulation. The SINBAD database is currently divided into three categories fission, fusion, and accelerator benchmarks. Where possible, each experiment is described and analyzed using deterministic or probabilistic (Monte Carlo) radiation transport software.

  20. Advancing Material Models for Automotive Forming Simulations

    Science.gov (United States)

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

    2005-08-01

    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

  1. Climate simulations for 1880-2003 with GISS modelE

    CERN Document Server

    Hansen, J; Bauer, S; Baum, E; Cairns, B; Canuto, V; Chandler, M; Cheng, Y; Cohen, A; Faluvegi, G; Fleming, E; Friend, A; Genio, A D; Hall, T; Jackman, C; Jonas, J; Kelley, M; Kharecha, P; Kiang, N Y; Koch, D; Labow, G; Lacis, A; Lerner, J; Lo, K; Menon, S; Miller, R; Nazarenko, L; Novakov, T; Oinas, V; Perlwitz, J; Rind, D; Romanou, A; Ruedy, R; Russell, G; Sato, M; Schmidt, G A; Schmunk, R; Shindell, D; Stone, P; Streets, D; Sun, S; Tausnev, N; Thresher, D; Unger, N; Yao, M; Zhang, S; Perlwitz, Ja.; Perlwitz, Ju.

    2006-01-01

    We carry out climate simulations for 1880-2003 with GISS modelE driven by ten measured or estimated climate forcings. 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 forcings, observations, unforced variability among model ensemble members, and, if available, observed variability. Discrepancies between observations and simulations with all forcings are due to model deficiencies, inaccurate or incomplete forcings, 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 forcings, we aim to provide a benchmark against which the effect of improvements in the model, climate forcings, and observations can be tested. Principal model deficiencies...

  2. Benchmarking Asteroid-Deflection Experiment

    Science.gov (United States)

    Remington, Tane; Bruck Syal, Megan; Owen, John Michael; Miller, Paul L.

    2016-10-01

    An asteroid impacting Earth could have devastating consequences. In preparation to deflect or disrupt one before it reaches Earth, it is imperative to have modeling capabilities that adequately simulate the deflection actions. Code validation is key to ensuring full confidence in simulation results used in an asteroid-mitigation plan. We are benchmarking well-known impact experiments using Spheral, an adaptive smoothed-particle hydrodynamics code, to validate our modeling of asteroid deflection. We describe our simulation results, compare them with experimental data, and discuss what we have learned from our work. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-695540

  3. The Benchmarking of the Government to Employee (G2e) Technology Development: Theoretical Aspects of the Model Construction

    OpenAIRE

    Alvydas Baležentis; Gintarė Paražinskaitė

    2012-01-01

    Purpose—To fill the gap in the currently very rare discussion on the important topic of e-government research—design, development and usage of information and communication technologies for human resource management in the public sector and to formulate theoretical benchmarks for development of the government to employee (G2E) model.Design/methodology/approach—Literature analysis of mostly empirical research from the field of government to government (G2G), government to citizen (G2C) and bus...

  4. Frequency regulators for the nonperturbative renormalization group: a general study and the model A as a benchmark

    CERN Document Server

    Duclut, Charlie

    2016-01-01

    We derive the necessary conditions for implementing a regulator that depends on both momentum and frequency in the nonperturbative renormalization group flow equations of out-of-equilibrium statistical systems. We consider model A as a benchmark and compute its dynamical critical exponent $z$. This allows us to show that frequency regulators compatible with causality and the fluctuation-dissipation theorem can be devised. We show that when the Principle of Minimal Sensitivity (PMS) is employed to optimize the critical exponents $\\eta$, $\

  5. Comparative Benchmark Dose Modeling as a Tool to Make the First Estimate of Safe Human Exposure Levels to Lunar Dust

    Science.gov (United States)

    James, John T.; Lam, Chiu-wing; Scully, Robert R.

    2013-01-01

    Brief exposures of Apollo Astronauts to lunar dust occasionally elicited upper respiratory irritation; however, no limits were ever set for prolonged exposure ot lunar dust. Habitats for exploration, whether mobile of fixed must be designed to limit human exposure to lunar dust to safe levels. We have used a new technique we call Comparative Benchmark Dose Modeling to estimate safe exposure limits for lunar dust collected during the Apollo 14 mission.

  6. Code assessment and modelling for Design Basis Accident Analysis of the European sodium fast reactor design. Part I: System description, modelling and benchmarking

    Energy Technology Data Exchange (ETDEWEB)

    Lázaro, A., E-mail: aurelio.lazaro-chueca@ec.europa.eu [JRC-IET European Commission—Westerduinweg 3, PO Box-2, 1755 ZG Petten (Netherlands); UPV—Universidad Politecnica de Valencia, Cami de vera s/n-46002, Valencia (Spain); Ammirabile, L. [JRC-IET European Commission—Westerduinweg 3, PO Box-2, 1755 ZG Petten (Netherlands); Bandini, G. [ENEA, Via Martiri di Monte Sole 4, 40129 Bologna (Italy); Darmet, G.; Massara, S. [EDF, 1 avenue du Général de Gaulle, 92141 Clamart (France); Dufour, Ph.; Tosello, A. [CEA, St Paul lez Durance, 13108 Cadarache (France); Gallego, E.; Jimenez, G. [UPM, José Gutiérrez Abascal, 2-28006 Madrid (Spain); Mikityuk, K. [PSI—Paul Scherrer Institut, 5232 Villigen Switzerland (Switzerland); Schikorr, M.; Bubelis, E.; Ponomarev, A.; Kruessmann, R. [KIT—Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen Germany (Germany); Stempniewicz, M. [NRG, Utrechtseweg 310, PO Box 9034 6800 ES, Arnhem (Netherlands)

    2014-01-15

    Highlights: • Ten system-code models of the ESFR were developed in the frame of the CP-ESFR project. • Eight different thermohydraulic system codes adapted to sodium fast reactor's technology. • Benchmarking exercise settled to check the consistency of the calculations. • Upgraded system codes able to simulate the reactivity feedback and key safety parameters. -- Abstract: The new reactor concepts proposed in the Generation IV International Forum (GIF) are conceived to improve the use of natural resources, reduce the amount of high-level radioactive waste and excel in their reliability and safe operation. Among these novel designs sodium fast reactors (SFRs) stand out due to their technological feasibility as demonstrated in several countries during the last decades. As part of the contribution of EURATOM to GIF the CP-ESFR is a collaborative project with the objective, among others, to perform extensive analysis on safety issues involving renewed SFR demonstrator designs. The verification of computational tools able to simulate the plant behaviour under postulated accidental conditions by code-to-code comparison was identified as a key point to ensure reactor safety. In this line, several organizations employed coupled neutronic and thermal-hydraulic system codes able to simulate complex and specific phenomena involving multi-physics studies adapted to this particular fast reactor technology. In the “Introduction” of this paper the framework of this study is discussed, the second section describes the envisaged plant design and the commonly agreed upon modelling guidelines. The third section presents a comparative analysis of the calculations performed by each organisation applying their models and codes to a common agreed transient with the objective to harmonize the models as well as validating the implementation of all relevant physical phenomena in the different system codes.

  7. Benchmark Comparison of Dual- and Quad-Core Processor Linux Clusters with Two Global Climate Modeling Workloads

    Science.gov (United States)

    McGalliard, James

    2008-01-01

    This viewgraph presentation details the science and systems environments that NASA High End computing program serves. Included is a discussion of the workload that is involved in the processing for the Global Climate Modeling. The Goddard Earth Observing System Model, Version 5 (GEOS-5) is a system of models integrated using the Earth System Modeling Framework (ESMF). The GEOS-5 system was used for the Benchmark tests, and the results of the tests are shown and discussed. Tests were also run for the Cubed Sphere system, results for these test are also shown.

  8. Preliminary assessment of Geant4 HP models and cross section libraries by reactor criticality benchmark calculations

    DEFF Research Database (Denmark)

    Cai, Xiao-Xiao; Llamas-Jansa, Isabel; Mullet, Steven

    2013-01-01

    to reactor modelling. Before version 9.5, Geant4 HP thermal scattering model (i.e. the S(α; β) model ) supports only three bounded isotopes, namely, H in water and polyethylene, and C in graphite. Newly supported materials include D in heavy water, O and Be in beryllium oxide, H and Zr in zirconium hydride......, U and O in uranium dioxide, Al metal, Be metal, and Fe metal. The native HP cross section library G4NDL does not include data for elements with atomic number larger than 92. Therefore, transuranic elements, which have impacts for a realistic reactor, can not be simulated by the combination of the HP...

  9. CFD Modeling of Thermal Manikin Heat Loss in a Comfort Evaluation Benchmark Test

    DEFF Research Database (Denmark)

    Nilsson, Håkan O.; Brohus, Henrik; Nielsen, Peter V.

    2007-01-01

    and companies still use several in-house codes for their calculations. The validation and association with human perception and heat losses in reality is consequently very difficult to make. This paper is providing requirements for the design and development of computer manikins and CFD benchmark tests...

  10. Benchmarking in European Higher Education: A Step beyond Current Quality Models

    Science.gov (United States)

    Burquel, Nadine; van Vught, Frans

    2010-01-01

    This paper presents the findings of a two-year EU-funded project (DG Education and Culture) "Benchmarking in European Higher Education", carried out from 2006 to 2008 by a consortium led by the European Centre for Strategic Management of Universities (ESMU), with the Centre for Higher Education Development, UNESCO-CEPES, and the…

  11. Comparative modeling and benchmarking data sets for human histone deacetylases and sirtuin families.

    Science.gov (United States)

    Xia, Jie; Tilahun, Ermias Lemma; Kebede, Eyob Hailu; Reid, Terry-Elinor; Zhang, Liangren; Wang, Xiang Simon

    2015-02-23

    Histone deacetylases (HDACs) are an important class of drug targets for the treatment of cancers, neurodegenerative diseases, and other types of diseases. Virtual screening (VS) has become fairly effective approaches for drug discovery of novel and highly selective histone deacetylase inhibitors (HDACIs). To facilitate the process, we constructed maximal unbiased benchmarking data sets for HDACs (MUBD-HDACs) using our recently published methods that were originally developed for building unbiased benchmarking sets for ligand-based virtual screening (LBVS). The MUBD-HDACs cover all four classes including Class III (Sirtuins family) and 14 HDAC isoforms, composed of 631 inhibitors and 24609 unbiased decoys. Its ligand sets have been validated extensively as chemically diverse, while the decoy sets were shown to be property-matching with ligands and maximal unbiased in terms of "artificial enrichment" and "analogue bias". We also conducted comparative studies with DUD-E and DEKOIS 2.0 sets against HDAC2 and HDAC8 targets and demonstrate that our MUBD-HDACs are unique in that they can be applied unbiasedly to both LBVS and SBVS approaches. In addition, we defined a novel metric, i.e. NLBScore, to detect the "2D bias" and "LBVS favorable" effect within the benchmarking sets. In summary, MUBD-HDACs are the only comprehensive and maximal-unbiased benchmark data sets for HDACs (including Sirtuins) that are available so far. MUBD-HDACs are freely available at http://www.xswlab.org/ .

  12. Modeling and simulation of longwall scraper conveyor considering operational faults

    Science.gov (United States)

    Cenacewicz, Krzysztof; Katunin, Andrzej

    2016-06-01

    The paper provides a description of analytical model of a longwall scraper conveyor, including its electrical, mechanical, measurement and control actuating systems, as well as presentation of its implementation in the form of computer simulator in the Matlab®/Simulink® environment. Using this simulator eight scenarios typical of usual operational conditions of an underground scraper conveyor can be generated. Moreover, the simulator provides a possibility of modeling various operational faults and taking into consideration a measurement noise generated by transducers. The analysis of various combinations of scenarios of operation and faults with description is presented. The simulator developed may find potential application in benchmarking of diagnostic systems, testing of algorithms of operational control or can be used for supporting the modeling of real processes occurring in similar systems.

  13. 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.

  14. Developed hydraulic simulation model for water pipeline networks

    Directory of Open Access Journals (Sweden)

    A. Ayad

    2013-03-01

    Full Text Available A numerical method that uses linear graph theory is presented for both steady state, and extended period simulation in a pipe network including its hydraulic components (pumps, valves, junctions, etc.. The developed model is based on the Extended Linear Graph Theory (ELGT technique. This technique is modified to include new network components such as flow control valves and tanks. The technique also expanded for extended period simulation (EPS. A newly modified method for the calculation of updated flows improving the convergence rate is being introduced. Both benchmarks, ad Actual networks are analyzed to check the reliability of the proposed method. The results reveal the finer performance of the proposed method.

  15. Assessment of Static Delamination Propagation Capabilities in Commercial Finite Element Codes Using Benchmark Analysis

    Science.gov (United States)

    Orifici, Adrian C.; Krueger, Ronald

    2010-01-01

    With capabilities for simulating delamination growth in composite materials becoming available, the need for benchmarking and assessing these capabilities is critical. In this study, benchmark analyses were performed to assess the delamination propagation simulation capabilities of the VCCT implementations in Marc TM and MD NastranTM. Benchmark delamination growth results for Double Cantilever Beam, Single Leg Bending and End Notched Flexure specimens were generated using a numerical approach. This numerical approach was developed previously, and involves comparing results from a series of analyses at different delamination lengths to a single analysis with automatic crack propagation. Specimens were analyzed with three-dimensional and two-dimensional models, and compared with previous analyses using Abaqus . The results demonstrated that the VCCT implementation in Marc TM and MD Nastran(TradeMark) was capable of accurately replicating the benchmark delamination growth results and that the use of the numerical benchmarks offers advantages over benchmarking using experimental and analytical results.

  16. Dark Matter Benchmark Models for Early LHC Run-2 Searches: Report of the ATLAS/CMS Dark Matter Forum

    OpenAIRE

    Abercrombie, Daniel; Akchurin, Nural; Akilli, Ece; Maestre, Juan Alcaraz; Allen, Brandon; Gonzalez, Barbara Alvarez; Andrea, Jeremy; Arbey, Alexandre; Azuelos, Georges; Azzi, Patrizia; Backović, Mihailo; Bai, Yang; Banerjee, Swagato; Beacham, James; Belyaev, Alexander

    2015-01-01

    This document is the final report of the ATLAS-CMS Dark Matter Forum, a forum organized by the ATLAS and CMS collaborations with the participation of experts on theories of Dark Matter, to select a minimal basis set of dark matter simplified models that should support the design of the early LHC Run-2 searches. A prioritized, compact set of benchmark models is proposed, accompanied by studies of the parameter space of these models and a repository of generator implementations. This report als...

  17. Dark Matter Benchmark Models for Early LHC Run-2 Searches: Report of the ATLAS/CMS Dark Matter Forum

    CERN Document Server

    Abercrombie, Daniel; Akilli, Ece; Alcaraz Maestre, Juan; Allen, Brandon; Alvarez Gonzalez, Barbara; Andrea, Jeremy; Arbey, Alexandre; Azuelos, Georges; Azzi, Patrizia; Backovic, Mihailo; Bai, Yang; Banerjee, Swagato; Beacham, James; Belyaev, Alexander; Boveia, Antonio; Brennan, Amelia Jean; Buchmueller, Oliver; Buckley, Matthew R.; Busoni, Giorgio; Buttignol, Michael; Cacciapaglia, Giacomo; Caputo, Regina; Carpenter, Linda; Filipe Castro, Nuno; Gomez Ceballos, Guillelmo; Cheng, Yangyang; Chou, John Paul; Cortes Gonzalez, Arely; Cowden, Chris; D'Eramo, Francesco; De Cosa, Annapaola; De Gruttola, Michele; De Roeck, Albert; De Simone, Andrea; Deandrea, Aldo; Demiragli, Zeynep; DiFranzo, Anthony; Doglioni, Caterina; du Pree, Tristan; Erbacher, Robin; Erdmann, Johannes; Fischer, Cora; Flaecher, Henning; Fox, Patrick J.; Fuks, Benjamin; Genest, Marie-Helene; Gomber, Bhawna; Goudelis, Andreas; Gramling, Johanna; Gunion, John; Hahn, Kristian; Haisch, Ulrich; Harnik, Roni; Harris, Philip C.; Hoepfner, Kerstin; Hoh, Siew Yan; Hsu, Dylan George; Hsu, Shih-Chieh; Iiyama, Yutaro; Ippolito, Valerio; Jacques, Thomas; Ju, Xiangyang; Kahlhoefer, Felix; Kalogeropoulos, Alexis; Kaplan, Laser Seymour; Kashif, Lashkar; Khoze, Valentin V.; Khurana, Raman; Kotov, Khristian; Kovalskyi, Dmytro; Kulkarni, Suchita; Kunori, Shuichi; Kutzner, Viktor; Lee, Hyun Min; Lee, Sung-Won; Liew, Seng Pei; Lin, Tongyan; Lowette, Steven; Madar, Romain; Malik, Sarah; Maltoni, Fabio; Martinez Perez, Mario; Mattelaer, Olivier; Mawatari, Kentarou; McCabe, Christopher; Megy, Theo; Morgante, Enrico; Mrenna, Stephen; Narayanan, Siddharth M.; Nelson, Andy; Novaes, Sergio F.; Padeken, Klaas Ole; Pani, Priscilla; Papucci, Michele; Paulini, Manfred; Paus, Christoph; Pazzini, Jacopo; Penning, Bjorn; Peskin, Michael E.; Pinna, Deborah; Procura, Massimiliano; Qazi, Shamona F.; Racco, Davide; Re, Emanuele; Riotto, Antonio; Rizzo, Thomas G.; Roehrig, Rainer; Salek, David; Sanchez Pineda, Arturo; Sarkar, Subir; Schmidt, Alexander; Schramm, Steven Randolph; Shepherd, William; Singh, Gurpreet; Soffi, Livia; Srimanobhas, Norraphat; Sung, Kevin; Tait, Tim M.P.; Theveneaux-Pelzer, Timothee; Thomas, Marc; Tosi, Mia; Trocino, Daniele; Undleeb, Sonaina; Vichi, Alessandro; Wang, Fuquan; Wang, Lian-Tao; Wang, Ren-Jie; Whallon, Nikola; Worm, Steven; Wu, Mengqing; Wu, Sau Lan; Yang, Hongtao; Yang, Yong; Yu, Shin-Shan; Zaldivar, Bryan; Zanetti, Marco; Zhang, Zhiqing; Zucchetta, Alberto

    2015-01-01

    This document is the final report of the ATLAS-CMS Dark Matter Forum, a forum organized by the ATLAS and CMS collaborations with the participation of experts on theories of Dark Matter, to select a minimal basis set of dark matter simplified models that should support the design of the early LHC Run-2 searches. A prioritized, compact set of benchmark models is proposed, accompanied by studies of the parameter space of these models and a repository of generator implementations. This report also addresses how to apply the Effective Field Theory formalism for collider searches and present the results of such interpretations.

  18. Monte Carlo simulations and benchmark measurements on the response of TE(TE) and Mg(Ar) ionization chambers in photon, electron and neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yi-Chun [Health Physics Division, Institute of Nuclear Energy Research, Taoyuan County, Taiwan (China); Huang, Tseng-Te, E-mail: huangtt@iner.gov.tw [Health Physics Division, Institute of Nuclear Energy Research, Taoyuan County, Taiwan (China); Liu, Yuan-Hao [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu City, Taiwan (China); Chen, Wei-Lin [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu City, Taiwan (China); Chen, Yen-Fu [Atomic Energy Council, New Taipei City, Taiwan (China); Wu, Shu-Wei [Dept. of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan (China); Nievaart, Sander [Institute for Energy, Joint Research Centre, European Commission, Petten (Netherlands); Jiang, Shiang-Huei [Dept. of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan (China)

    2015-06-01

    reached 7.8–16.5% below 120 kVp X-ray beams. In this study, we were especially interested in BNCT doses where low energy photon contribution is less to ignore, MCNP model is recognized as the most suitable to simulate wide photon–electron and neutron energy distributed responses of the paired ICs. Also, MCNP provides the best prediction of BNCT source adjustment by the detector’s neutron and photon responses. - Highlights: • We established optimal T2 & M2 paired ICs model in benchmark x, γ, e & n fields. • We used MCNP, EGSnrc, FLUKA or GEANT4 for IC current simulations. • In keV photon, MCNP underestimated M2 response, but accurately estimated T2. • On detector response, we commented for source component adjustment. • For BNCT, MCNP still provides the best prediction of n & photon responses.

  19. Evaluating uncertainty in simulation models

    Energy Technology Data Exchange (ETDEWEB)

    McKay, M.D.; Beckman, R.J.; Morrison, J.D.; Upton, S.C.

    1998-12-01

    The authors discussed some directions for research and development of methods for assessing simulation variability, input uncertainty, and structural model uncertainty. Variance-based measures of importance for input and simulation variables arise naturally when using the quadratic loss function of the difference between the full model prediction y and the restricted prediction {tilde y}. The concluded that generic methods for assessing structural model uncertainty do not now exist. However, methods to analyze structural uncertainty for particular classes of models, like discrete event simulation models, may be attainable.

  20. 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.

  1. Benchmarking geant4 nuclear models for hadron therapy with 95 MeV/nucleon carbon ions

    Science.gov (United States)

    Dudouet, J.; Cussol, D.; Durand, D.; Labalme, M.

    2014-05-01

    In carbon therapy, the interaction of the incoming beam with human tissue may lead to the production of a large amount of nuclear fragments and secondary light particles. An accurate estimation of the biological dose on the tumor and the surrounding healthy tissue thus requires sophisticated simulation tools based on nuclear reaction models. The validity of such models requires intensive comparisons with as many sets of experimental data as possible. Up to now, a rather limited set of double differential carbon fragmentation cross sections has been measured in the energy range used in hadron therapy (up to 400 MeV/nucleon). However, new data have been recently obtained at intermediate energy (95 MeV/nucleon). The aim of this work is to compare the reaction models embedded in the geant4 Monte Carlo toolkit with these new data. The strengths and weaknesses of each tested model, i.e., G4BinaryLightIonReaction, G4QMDReaction, and INCL++, coupled to two different de-excitation models, i.e., the generalized evaporation model and the Fermi break-up model, are discussed.

  2. 一个针对并行模拟引擎的性能评测实例%Parallel Benchmark for Evaluating Parallel Simulation Engine

    Institute of Scientific and Technical Information of China (English)

    吴志敏; 吕慧伟; 陈明宇

    2013-01-01

    SimK is a parallel discrete event simulation engine developed by state key laboratory of computer architecture in institute of computing technology, chinese academy of sciences. Based on the released SimK-1. 0, we extended the function of task partition and the blocking controlling in the process of synchronization. We released version 1. 1 of SimK. On the other hand,as it lacks a benchmark to specifically SimK simulation performance and there is no comprehensive evaluation data, we first proposed the rules of development Benchmark for parallel simulation engine. Then we introduced the example "PassBall". We used it to do the evaluation of SimK on the weak and strong scalability, as well as the strong scalability in unbalanced workload condition. Then we compared the speed-up ratio between the balanced workload and unbalanced workload condition in strong scalability test The influence of simulated computing workload on speed-up ration from was also explored. We also discussed the applicability of the Benchmark. It can be concluded from our experiments as follows:a)our example "PassBall" is available to be the benchmark for SimK,as well as other parallel simulation engine. b)SimK has favorable strong and weak scalability. c)Both the load balance and the simulated computing workload will have effect on the speed-up ratio.%SimK是由中科院计算所体系结构国家重点实验室开发的一个并行离散时间模拟引擎.基于已经发布的SimK1.0版本,对任务划分及同步推进阻塞控制进行了功能扩展,开发了SimK的1.1版本.同时由于缺乏一个专门对SimK模拟性能评测的Benchmark以及全面的评测结果,首先讨论了并行模拟引擎Benchmark的设计准则,之后介绍了开发的Benchmark-PassBall,并且使用它对SimK的强弱扩展性、组件负载不均衡情况下的强扩展性进行了评测,同时对比了组件负载不均衡和均衡情况下的加速比,探讨了模拟计算量的变化对模拟加速比的影

  3. 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

  4. Active vibration control of nonlinear benchmark buildings

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xing-de; CHEN Dao-zheng

    2007-01-01

    The present nonlinear model reduction methods unfit the nonlinear benchmark buildings as their vibration equations belong to a non-affine system. Meanwhile,the controllers designed directly by the nonlinear control strategy have a high order, and they are difficult to be applied actually. Therefore, a new active vibration control way which fits the nonlinear buildings is proposed. The idea of the proposed way is based on the model identification and structural model linearization, and exerting the control force to the built model according to the force action principle. This proposed way has a better practicability as the built model can be reduced by the balance reduction method based on the empirical Grammian matrix. A three-story benchmark structure is presented and the simulation results illustrate that the proposed method is viable for the civil engineering structures.

  5. IVOA Recommendation: Simulation Data Model

    CERN Document Server

    Lemson, Gerard; Cervino, Miguel; Gheller, Claudio; Gray, Norman; LePetit, Franck; Louys, Mireille; Ooghe, Benjamin; Wagner, Rick; Wozniak, Herve

    2014-01-01

    In this document and the accompanying documents we describe a data model (Simulation Data Model) describing numerical computer simulations of astrophysical systems. The primary goal of this standard is to support discovery of simulations by describing those aspects of them that scientists might wish to query on, i.e. it is a model for meta-data describing simulations. This document does not propose a protocol for using this model. IVOA protocols are being developed and are supposed to use the model, either in its original form or in a form derived from the model proposed here, but more suited to the particular protocol. The SimDM has been developed in the IVOA Theory Interest Group with assistance of representatives of relevant working groups, in particular DM and Semantics.

  6. Comparison of the PHISICS/RELAP5-3D Ring and Block Model Results for Phase I of the OECD MHTGR-350 Benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Gerhard Strydom

    2014-04-01

    The INL PHISICS code system consists of three modules providing improved core simulation capability: INSTANT (performing 3D nodal transport core calculations), MRTAU (depletion and decay heat generation) and a perturbation/mixer module. Coupling of the PHISICS code suite to the thermal hydraulics system code RELAP5-3D has recently been finalized, and as part of the code verification and validation program the exercises defined for Phase I of the OECD/NEA MHTGR 350 MW Benchmark were completed. This paper provides an overview of the MHTGR Benchmark, and presents selected results of the three steady state exercises 1-3 defined for Phase I. For Exercise 1, a stand-alone steady-state neutronics solution for an End of Equilibrium Cycle Modular High Temperature Reactor (MHTGR) was calculated with INSTANT, using the provided geometry, material descriptions, and detailed cross-section libraries. Exercise 2 required the modeling of a stand-alone thermal fluids solution. The RELAP5-3D results of four sub-cases are discussed, consisting of various combinations of coolant bypass flows and material thermophysical properties. Exercise 3 combined the first two exercises in a coupled neutronics and thermal fluids solution, and the coupled code suite PHISICS/RELAP5-3D was used to calculate the results of two sub-cases. The main focus of the paper is a comparison of the traditional RELAP5-3D “ring” model approach vs. a much more detailed model that include kinetics feedback on individual block level and thermal feedbacks on a triangular sub-mesh. The higher fidelity of the block model is illustrated with comparison results on the temperature, power density and flux distributions, and the typical under-predictions produced by the ring model approach are highlighted.

  7. Benchmark experiments with global climate models applicable to extra-solar gas giant planets in the shallow atmosphere approximation

    CERN Document Server

    Bending, V L; Kolb, U

    2012-01-01

    The growing field of exoplanetary atmospheric modelling has seen little work on standardised benchmark tests for its models, limiting understanding of the dependence of results on specific models and conditions. With spatially resolved observations as yet difficult to obtain, such a test is invaluable. Although an intercomparison test for models of tidally locked gas giant planets has previously been suggested and carried out, the data provided were limited in terms of comparability. Here, the shallow PUMA model is subjected to such a test, and detailed statistics produced to facilitate comparison, with both time means and the associated standard deviations displayed, removing the time dependence and providing a measure of the variability. Model runs have been analysed to determine the variability between resolutions, and the effect of resolution on the energy spectra studied. Superrotation is a robust and reproducible feature at all resolutions.

  8. Fundamental M-dwarf parameters from high-resolution spectra using PHOENIX ACES models: I. Parameter accuracy and benchmark stars

    CERN Document Server

    Passegger, Vera Maria; Reiners, Ansgar

    2016-01-01

    M-dwarf stars are the most numerous stars in the Universe; they span a wide range in mass and are in the focus of ongoing and planned exoplanet surveys. To investigate and understand their physical nature, detailed spectral information and accurate stellar models are needed. We use a new synthetic atmosphere model generation and compare model spectra to observations. To test the model accuracy, we compared the models to four benchmark stars with atmospheric parameters for which independent information from interferometric radius measurements is available. We used $\\chi^2$ -based methods to determine parameters from high-resolution spectroscopic observations. Our synthetic spectra are based on the new PHOENIX grid that uses the ACES description for the equation of state. This is a model generation expected to be especially suitable for the low-temperature atmospheres. We identified suitable spectral tracers of atmospheric parameters and determined the uncertainties in $T_{\\rm eff}$, $\\log{g}$, and [Fe/H] resul...

  9. Benchmarking Danish Industries

    DEFF Research Database (Denmark)

    Gammelgaard, Britta; Bentzen, Eric; Aagaard Andreassen, Mette

    2003-01-01

    compatible survey. The International Manufacturing Strategy Survey (IMSS) doesbring up the question of supply chain management, but unfortunately, we did not have access to thedatabase. Data from the members of the SCOR-model, in the form of benchmarked performance data,may exist, but are nonetheless...... not public. The survey is a cooperative project "Benchmarking DanishIndustries" with CIP/Aalborg University, the Danish Technological University, the DanishTechnological Institute and Copenhagen Business School as consortia partners. The project has beenfunded by the Danish Agency for Trade and Industry...

  10. Benchmarking GEANT4 nuclear models for carbon-therapy at 95 MeV/A

    CERN Document Server

    Dudouet, J; Durand, D; Labalme, M

    2013-01-01

    In carbon-therapy, the interaction of the incoming beam with human tissues may lead to the production of a large amount of nuclear fragments and secondary light particles. An accurate estimation of the biological dose deposited into the tumor and the surrounding healthy tissues thus requires sophisticated simulation tools based on nuclear reaction models. The validity of such models requires intensive comparisons with as many sets of experimental data as possible. Up to now, a rather limited set of double di erential carbon fragmentation cross sections have been measured in the energy range used in hadrontherapy (up to 400 MeV/A). However, new data have been recently obtained at intermediate energy (95 MeV/A). The aim of this work is to compare the reaction models embedded in the GEANT4 Monte Carlo toolkit with these new data. The strengths and weaknesses of each tested model, i.e. G4BinaryLightIonReaction, G4QMDReaction and INCL++, coupled to two di fferent de-excitation models, i.e. the generalized evaporat...

  11. Benchmarking Exercises To Validate The Updated ELLWF GoldSim Slit Trench Model

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, G. A.; Hiergesell, R. A.

    2013-11-12

    The Savannah River National Laboratory (SRNL) results of the 2008 Performance Assessment (PA) (WSRC, 2008) sensitivity/uncertainty analyses conducted for the trenches located in the EArea LowLevel Waste Facility (ELLWF) were subject to review by the United States Department of Energy (U.S. DOE) Low-Level Waste Disposal Facility Federal Review Group (LFRG) (LFRG, 2008). LFRG comments were generally approving of the use of probabilistic modeling in GoldSim to support the quantitative sensitivity analysis. A recommendation was made, however, that the probabilistic models be revised and updated to bolster their defensibility. SRS committed to addressing those comments and, in response, contracted with Neptune and Company to rewrite the three GoldSim models. The initial portion of this work, development of Slit Trench (ST), Engineered Trench (ET) and Components-in-Grout (CIG) trench GoldSim models, has been completed. The work described in this report utilizes these revised models to test and evaluate the results against the 2008 PORFLOW model results. This was accomplished by first performing a rigorous code-to-code comparison of the PORFLOW and GoldSim codes and then performing a deterministic comparison of the two-dimensional (2D) unsaturated zone and three-dimensional (3D) saturated zone PORFLOW Slit Trench models against results from the one-dimensional (1D) GoldSim Slit Trench model. The results of the code-to-code comparison indicate that when the mechanisms of radioactive decay, partitioning of contaminants between solid and fluid, implementation of specific boundary conditions and the imposition of solubility controls were all tested using identical flow fields, that GoldSim and PORFLOW produce nearly identical results. It is also noted that GoldSim has an advantage over PORFLOW in that it simulates all radionuclides simultaneously - thus avoiding a potential problem as demonstrated in the Case Study (see Section 2.6). Hence, it was concluded that the follow

  12. Harmonic oscillator in heat bath: Exact simulation of time-lapse-recorded data and exact analytical benchmark statistics

    DEFF Research Database (Denmark)

    Nørrelykke, Simon F; Flyvbjerg, Henrik

    2011-01-01

    The stochastic dynamics of the damped harmonic oscillator in a heat bath is simulated with an algorithm that is exact for time steps of arbitrary size. Exact analytical results are given for correlation functions and power spectra in the form they acquire when computed from experimental time...... to the extent that it is interpreted as a damped harmonic oscillator at finite temperature-such as an AFM cantilever. (iii) Three other models of fundamental interest are limiting cases of the damped harmonic oscillator at finite temperature; it consequently bridges their differences and describes the effects...

  13. Modeling and Simulation with INS.

    Science.gov (United States)

    Roberts, Stephen D.; And Others

    INS, the Integrated Network Simulation language, puts simulation modeling into a network framework and automatically performs such programming activities as placing the problem into a next event structure, coding events, collecting statistics, monitoring status, and formatting reports. To do this, INS provides a set of symbols (nodes and branches)…

  14. A benchmark test suite for proton transfer energies and its use to test electronic structure model chemistries

    Science.gov (United States)

    Nachimuthu, Santhanamoorthi; Gao, Jiali; Truhlar, Donald G.

    2012-05-01

    We present benchmark calculations of nine selected points on potential energy surfaces describing proton transfer processes in three model systems, H5O2+, CH3OH…H+…OH2, and CH3COOH…OH2. The calculated relative energies of these geometries are compared to those calculated by various wave function and density functional methods, including the polarized molecular orbital (PMO) model recently developed in our research group and other semiempirical molecular orbital methods. We found that the SCC-DFTB and PMO methods (the latter available so far only for molecules consisting of only O and H and therefore only for the first of the three model systems) give results that are, on average, within 2 kcal/mol of the benchmark results. Other semiempirical molecular orbital methods have mean unsigned errors (MUEs) of 3-8 kcal/mol, local density functionals have MUEs in the range 0.7-3.7 kcal/mol, and hybrid density functionals have MUEs of only 0.3-1.0 kcal/mol, with the best density functional performance obtained by hybrid meta-GGAs, especially M06 and PW6B95.

  15. Modeling and Simulating Environmental Effects

    OpenAIRE

    Guest, Peter S.; Murphree, Tom; Frederickson, Paul A.; Guest, Arlene A.

    2012-01-01

    MOVES Research & Education Systems Seminar: Presentation; Session 4: Collaborative NWDC/NPS M&S Research; Moderator: Curtis Blais; Modeling and Simulating Environmental Effects; speakers: Peter Guest, Paul Frederickson & Tom Murphree Environmental Effects Group

  16. TREAT Modeling and Simulation Strategy

    Energy Technology Data Exchange (ETDEWEB)

    DeHart, Mark David [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    This report summarizes a four-phase process used to describe the strategy in developing modeling and simulation software for the Transient Reactor Test Facility. The four phases of this research and development task are identified as (1) full core transient calculations with feedback, (2) experiment modeling, (3) full core plus experiment simulation and (4) quality assurance. The document describes the four phases, the relationship between these research phases, and anticipated needs within each phase.

  17. Harmonic Oscillator in Heat Bath: Exact simulation of time-lapse-recorded data, exact analytical benchmark statistics

    CERN Document Server

    Norrelykke, Simon F

    2011-01-01

    The stochastic dynamics of the damped harmonic oscillator in a heat bath is simulated with an algorithm that is exact for time steps of arbitrary size. Exact analytical results are given for correlation functions and power spectra in the form they acquire when computed from experimental time-lapse recordings. Three applications are discussed: (i) Effects of finite sampling-rate and -time, described exactly here, are similar for other stochastic dynamical systems-e.g. motile micro-organisms and their time-lapse recorded trajectories. (ii) The same statistics is satisfied by any experimental system to the extent it is interpreted as a damped harmonic oscillator at finite temperature-such as an AFM cantilever. (iii) Three other models of fundamental interest are limiting cases of the damped harmonic oscillator at finite temperature; it consequently bridges their differences and describes effects of finite sampling rate and sampling time for these models as well. Finally, we give a brief discussion of nondimensio...

  18. Performance modeling & simulation of complex systems (A systems engineering design & analysis approach)

    Science.gov (United States)

    Hall, Laverne

    1995-01-01

    Modeling of the Multi-mission Image Processing System (MIPS) will be described as an example of the use of a modeling tool to design a distributed system that supports multiple application scenarios. This paper examines: (a) modeling tool selection, capabilities, and operation (namely NETWORK 2.5 by CACl), (b) pointers for building or constructing a model and how the MIPS model was developed, (c) the importance of benchmarking or testing the performance of equipment/subsystems being considered for incorporation the design/architecture, (d) the essential step of model validation and/or calibration using the benchmark results, (e) sample simulation results from the MIPS model, and (f) how modeling and simulation analysis affected the MIPS design process by having a supportive and informative impact.

  19. 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

  20. Issues in benchmarking human reliability analysis methods : a literature review.

    Energy Technology Data Exchange (ETDEWEB)

    Lois, Erasmia (US Nuclear Regulatory Commission); Forester, John Alan; Tran, Tuan Q. (Idaho National Laboratory, Idaho Falls, ID); Hendrickson, Stacey M. Langfitt; Boring, Ronald L. (Idaho National Laboratory, Idaho Falls, ID)

    2008-04-01

    There is a diversity of human reliability analysis (HRA) methods available for use in assessing human performance within probabilistic risk assessment (PRA). Due to the significant differences in the methods, including the scope, approach, and underlying models, there is a need for an empirical comparison investigating the validity and reliability of the methods. To accomplish this empirical comparison, a benchmarking study is currently underway that compares HRA methods with each other and against operator performance in simulator studies. In order to account for as many effects as possible in the construction of this benchmarking study, a literature review was conducted, reviewing past benchmarking studies in the areas of psychology and risk assessment. A number of lessons learned through these studies are presented in order to aid in the design of future HRA benchmarking endeavors.

  1. 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

  2. Time-resolved particle image velocimetry measurements with wall shear stress and uncertainty quantification for the FDA benchmark nozzle model

    CERN Document Server

    Raben, Jaime S; Robinson, Ronald; Malinauskas, Richard; Vlachos, Pavlos P

    2014-01-01

    We present validation of benchmark experimental data for computational fluid dynamics (CFD) analyses of medical devices using advanced Particle Image Velocimetry (PIV) processing and post-processing techniques. This work is an extension of a previous FDA-sponsored multi-laboratory study, which used a medical device mimicking geometry referred to as the FDA benchmark nozzle model. Time-resolved PIV analysis was performed in five overlapping regions of the model for Reynolds numbers in the nozzle throat of 500, 2,000, 5,000, and 8,000. Images included a two-fold increase in spatial resolution in comparison to the previous study. Data was processed using ensemble correlation, dynamic range enhancement, and phase correlations to increase signal-to-noise ratios and measurement accuracy, and to resolve flow regions with large velocity ranges and gradients, which is typical of many blood-contacting medical devices. Parameters relevant to device safety, including shear stress at the wall and in bulk flow, were comput...

  3. Monte Carlo simulations and benchmark measurements on the response of TE(TE) and Mg(Ar) ionization chambers in photon, electron and neutron beams

    Science.gov (United States)

    Lin, Yi-Chun; Huang, Tseng-Te; Liu, Yuan-Hao; Chen, Wei-Lin; Chen, Yen-Fu; Wu, Shu-Wei; Nievaart, Sander; Jiang, Shiang-Huei

    2015-06-01

    The paired ionization chambers (ICs) technique is commonly employed to determine neutron and photon doses in radiology or radiotherapy neutron beams, where neutron dose shows very strong dependence on the accuracy of accompanying high energy photon dose. During the dose derivation, it is an important issue to evaluate the photon and electron response functions of two commercially available ionization chambers, denoted as TE(TE) and Mg(Ar), used in our reactor based epithermal neutron beam. Nowadays, most perturbation corrections for accurate dose determination and many treatment planning systems are based on the Monte Carlo technique. We used general purposed Monte Carlo codes, MCNP5, EGSnrc, FLUKA or GEANT4 for benchmark verifications among them and carefully measured values for a precise estimation of chamber current from absorbed dose rate of cavity gas. Also, energy dependent response functions of two chambers were calculated in a parallel beam with mono-energies from 20 keV to 20 MeV photons and electrons by using the optimal simple spherical and detailed IC models. The measurements were performed in the well-defined (a) four primary M-80, M-100, M120 and M150 X-ray calibration fields, (b) primary 60Co calibration beam, (c) 6 MV and 10 MV photon, (d) 6 MeV and 18 MeV electron LINACs in hospital and (e) BNCT clinical trials neutron beam. For the TE(TE) chamber, all codes were almost identical over the whole photon energy range. In the Mg(Ar) chamber, MCNP5 showed lower response than other codes for photon energy region below 0.1 MeV and presented similar response above 0.2 MeV (agreed within 5% in the simple spherical model). With the increase of electron energy, the response difference between MCNP5 and other codes became larger in both chambers. Compared with the measured currents, MCNP5 had the difference from the measurement data within 5% for the 60Co, 6 MV, 10 MV, 6 MeV and 18 MeV LINACs beams. But for the Mg(Ar) chamber, the derivations reached 7

  4. Benchmarking Combined Biological Phosphorus and Nitrogen Removal Wastewater Treatment Processes

    DEFF Research Database (Denmark)

    Gernaey, Krist; Jørgensen, Sten Bay

    2004-01-01

    This paper describes the implementation of a simulation benchmark for studying the influence of control strategy implementations on combined nitrogen and phosphorus removal processes in a biological wastewater treatment plant. The presented simulation benchmark plant and its performance criteria...... are to a large extent based on the already existing nitrogen removal simulation benchmark. The paper illustrates and motivates the selection of the treatment plant lay-out, the selection of the biological process model, the development of realistic influent disturbance scenarios for dry, rain and storm weather...... conditions respectively, the definition of performance indexes that include the phosphorus removal processes, and the selection of a suitable operating point for the plant. Two control loops were implemented: one for dissolved oxygen control using the oxygen transfer coefficient K(L)a as manipulated variable...

  5. Benchmarking the Sandbox: Quantitative Comparisons of Numerical and Analogue Models of Brittle Wedge Dynamics (Invited)

    Science.gov (United States)

    Buiter, S.; Schreurs, G.; Geomod2008 Team

    2010-12-01

    , we find differences in shear zone dip angle and surface slope between numerical and analogue models and, in 3D experiments, along-strike variations of structures in map view. Our experiments point out that we need careful treatment of material properties, discontinuities in boundary conditions, model building techniques, and boundary friction for sandbox-like setups. We show that to first order we successfully simulate sandbox-style brittle behavior using different numerical modeling techniques and that we can obtain similar styles of deformation behavior in numerical and laboratory experiments at similar levels of variability. * The GeoMod2008 Team: M. Albertz, C. Beaumont, C. Burberry, J.-P. Callot, C. Cavozzi, M. Cerca, J.-H. Chen, E. Cristallini, A. Cruden, L. Cruz, M. Cooke, T. Crook, J.-M. Daniel, D. Egholm, S. Ellis, T. Gerya, L. Hodkinson, F. Hofmann, V Garcia, C. Gomes, C. Grall, Y. Guillot, C. Guzmán, T. Nur Hidayah, G. Hilley, B. Kaus, M. Klinkmüller, H. Koyi, W. Landry, C.-Y. Lu, J. Macauley, B. Maillot, C. Meriaux, Y. Mishin, F. Nilfouroushan, C.-C. Pan, C. Pascal, D. Pillot, R. Portillo, M.Rosenau, W. Schellart, R. Schlische, P. Souloumiac, A. Take, B. Vendeville, M. Vettori, M. Vergnaud, S.-H. Wang, M. Withjack, D. Yagupsky, Y. Yamada

  6. A VRLA battery simulation model

    Energy Technology Data Exchange (ETDEWEB)

    Pascoe, P.E.; Anbuky, A.H. [Invensys Energy Systems NZ Limited, Christchurch (New Zealand)

    2004-05-01

    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. (author)

  7. General introduction to simulation models

    DEFF Research Database (Denmark)

    Hisham Beshara Halasa, Tariq; Boklund, Anette

    2012-01-01

    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...

  8. COG validation: SINBAD Benchmark Problems

    Energy Technology Data Exchange (ETDEWEB)

    Lent, E M; Sale, K E; Buck, R M; Descalle, M

    2004-02-23

    We validated COG, a 3D Monte Carlo radiation transport code, against experimental data and MNCP4C simulations from the Shielding Integral Benchmark Archive Database (SINBAD) compiled by RSICC. We modeled three experiments: the Osaka Nickel and Aluminum sphere experiments conducted at the OKTAVIAN facility, and the liquid oxygen experiment conducted at the FNS facility. COG results are in good agreement with experimental data and generally within a few % of MCNP results. There are several possible sources of discrepancy between MCNP and COG results: (1) the cross-section database versions are different, MCNP uses ENDFB VI 1.1 while COG uses ENDFB VIR7, (2) the code implementations are different, and (3) the models may differ slightly. We also limited the use of variance reduction methods when running the COG version of the problems.

  9. Benchmarking and Performance Management

    Directory of Open Access Journals (Sweden)

    Adrian TANTAU

    2010-12-01

    Full Text Available The relevance of the chosen topic is explained by the meaning of the firm efficiency concept - the firm efficiency means the revealed performance (how well the firm performs in the actual market environment given the basic characteristics of the firms and their markets that are expected to drive their profitability (firm size, market power etc.. This complex and relative performance could be due to such things as product innovation, management quality, work organization, some other factors can be a cause even if they are not directly observed by the researcher. The critical need for the management individuals/group to continuously improve their firm/company’s efficiency and effectiveness, the need for the managers to know which are the success factors and the competitiveness determinants determine consequently, what performance measures are most critical in determining their firm’s overall success. Benchmarking, when done properly, can accurately identify both successful companies and the underlying reasons for their success. Innovation and benchmarking firm level performance are critical interdependent activities. Firm level variables, used to infer performance, are often interdependent due to operational reasons. Hence, the managers need to take the dependencies among these variables into account when forecasting and benchmarking performance. This paper studies firm level performance using financial ratio and other type of profitability measures. It uses econometric models to describe and then propose a method to forecast and benchmark performance.

  10. Robust fuzzy output feedback controller for affine nonlinear systems via T-S fuzzy bilinear model: CSTR benchmark.

    Science.gov (United States)

    Hamdy, M; Hamdan, I

    2015-07-01

    In this paper, a robust H∞ fuzzy output feedback controller is designed for a class of affine nonlinear systems with disturbance via Takagi-Sugeno (T-S) fuzzy bilinear model. The parallel distributed compensation (PDC) technique is utilized to design a fuzzy controller. The stability conditions of the overall closed loop T-S fuzzy bilinear model are formulated in terms of Lyapunov function via linear matrix inequality (LMI). The control law is robustified by H∞ sense to attenuate external disturbance. Moreover, the desired controller gains can be obtained by solving a set of LMI. A continuous stirred tank reactor (CSTR), which is a benchmark problem in nonlinear process control, is discussed in detail to verify the effectiveness of the proposed approach with a comparative study.

  11. 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.

  12. Simple benchmark for complex dose finding studies.

    Science.gov (United States)

    Cheung, Ying Kuen

    2014-06-01

    While a general goal of early phase clinical studies is to identify an acceptable dose for further investigation, modern dose finding studies and designs are highly specific to individual clinical settings. In addition, as outcome-adaptive dose finding methods often involve complex algorithms, it is crucial to have diagnostic tools to evaluate the plausibility of a method's simulated performance and the adequacy of the algorithm. In this article, we propose a simple technique that provides an upper limit, or a benchmark, of accuracy for dose finding methods for a given design objective. The proposed benchmark is nonparametric optimal in the sense of O'Quigley et al. (2002, Biostatistics 3, 51-56), and is demonstrated by examples to be a practical accuracy upper bound for model-based dose finding methods. We illustrate the implementation of the technique in the context of phase I trials that consider multiple toxicities and phase I/II trials where dosing decisions are based on both toxicity and efficacy, and apply the benchmark to several clinical examples considered in the literature. By comparing the operating characteristics of a dose finding method to that of the benchmark, we can form quick initial assessments of whether the method is adequately calibrated and evaluate its sensitivity to the dose-outcome relationships.

  13. Development of a chronic noncancer oral reference dose and drinking water screening level for sulfolane using benchmark dose modeling.

    Science.gov (United States)

    Thompson, Chad M; Gaylor, David W; Tachovsky, J Andrew; Perry, Camarie; Carakostas, Michael C; Haws, Laurie C

    2013-12-01

    Sulfolane is a widely used industrial solvent that is often used for gas treatment (sour gas sweetening; hydrogen sulfide removal from shale and coal processes, etc.), and in the manufacture of polymers and electronics, and may be found in pharmaceuticals as a residual solvent used in the manufacturing processes. Sulfolane is considered a high production volume chemical with worldwide production around 18 000-36 000 tons per year. Given that sulfolane has been detected as a contaminant in groundwater, an important potential route of exposure is tap water ingestion. Because there are currently no federal drinking water standards for sulfolane in the USA, we developed a noncancer oral reference dose (RfD) based on benchmark dose modeling, as well as a tap water screening value that is protective of ingestion. Review of the available literature suggests that sulfolane is not likely to be mutagenic, clastogenic or carcinogenic, or pose reproductive or developmental health risks except perhaps at very high exposure concentrations. RfD values derived using benchmark dose modeling were 0.01-0.04 mg kg(-1) per day, although modeling of developmental endpoints resulted in higher values, approximately 0.4 mg kg(-1) per day. The lowest, most conservative, RfD of 0.01 mg kg(-1) per day was based on reduced white blood cell counts in female rats. This RfD was used to develop a tap water screening level that is protective of ingestion, viz. 365 µg l(-1). It is anticipated that these values, along with the hazard identification and dose-response modeling described herein, should be informative for risk assessors and regulators interested in setting health-protective drinking water guideline values for sulfolane.

  14. 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.

  15. Kvantitativ benchmark - Produktionsvirksomheder

    DEFF Research Database (Denmark)

    Sørensen, Ole H.; Andersen, Vibeke

    Rapport med resultatet af kvantitativ benchmark over produktionsvirksomhederne i VIPS projektet.......Rapport med resultatet af kvantitativ benchmark over produktionsvirksomhederne i VIPS projektet....

  16. Benchmarking in Student Affairs.

    Science.gov (United States)

    Mosier, Robert E.; Schwarzmueller, Gary J.

    2002-01-01

    Discusses the use of benchmarking in student affairs, focusing on issues related to student housing. Provides examples of how benchmarking has influenced administrative practice at many institutions. (EV)

  17. 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....... 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....

  18. Computational Modeling of Simulation Tests.

    Science.gov (United States)

    1980-06-01

    Mexico , March 1979. 14. Kinney, G. F.,.::. IeiN, .hoce 1h Ir, McMillan, p. 57, 1962. 15. Courant and Friedrichs, ,U: r. on moca an.: Jho...AD 79 275 NEW MEXICO UNIV ALBUGUERGUE ERIC H WANG CIVIL ENGINE-ETC F/6 18/3 COMPUTATIONAL MODELING OF SIMULATION TESTS.(U) JUN 80 6 LEIGH, W CHOWN, B...COMPUTATIONAL MODELING OF SIMULATION TESTS00 0G. Leigh W. Chown B. Harrison Eric H. Wang Civil Engineering Research Facility University of New Mexico

  19. Optimized GPU simulation of continuous-spin glass models

    CERN Document Server

    Yavors'kii, Taras

    2012-01-01

    We develop a highly optimized code for simulating the Edwards-Anderson Heisenberg model on graphics processing units (GPUs). Using a number of computational tricks such as tiling, data compression and appropriate memory layouts, the simulation code combining over-relaxation, heat bath and parallel tempering moves achieves a peak performance of 0.29 ns per spin update on realistic system sizes, corresponding to a more than 150 fold speed-up over a serial CPU reference implementation. The optimized implementation is used to study the spin-glass transition in a random external magnetic field to probe the existence of a de Almeida-Thouless line in the model, for which we give benchmark results.

  20. Optimized GPU simulation of continuous-spin glass models

    Science.gov (United States)

    Yavors'kii, T.; Weigel, M.

    2012-08-01

    We develop a highly optimized code for simulating the Edwards-Anderson Heisenberg model on graphics processing units (GPUs). Using a number of computational tricks such as tiling, data compression and appropriate memory layouts, the simulation code combining over-relaxation, heat bath and parallel tempering moves achieves a peak performance of 0.29 ns per spin update on realistic system sizes, corresponding to a more than 150 fold speed-up over a serial CPU reference implementation. The optimized implementation is used to study the spin-glass transition in a random external magnetic field to probe the existence of a de Almeida-Thouless line in the model, for which we give benchmark results.

  1. Surrogate model approach for improving the performance of reactive transport simulations

    Science.gov (United States)

    Jatnieks, Janis; De Lucia, Marco; Sips, Mike; Dransch, Doris

    2016-04-01

    Reactive transport models can serve a large number of important geoscientific applications involving underground resources in industry and scientific research. It is common for simulation of reactive transport to consist of at least two coupled simulation models. First is a hydrodynamics simulator that is responsible for simulating the flow of groundwaters and transport of solutes. Hydrodynamics simulators are well established technology and can be very efficient. When hydrodynamics simulations are performed without coupled geochemistry, their spatial geometries can span millions of elements even when running on desktop workstations. Second is a geochemical simulation model that is coupled to the hydrodynamics simulator. Geochemical simulation models are much more computationally costly. This is a problem that makes reactive transport simulations spanning millions of spatial elements very difficult to achieve. To address this problem we propose to replace the coupled geochemical simulation model with a surrogate model. A surrogate is a statistical model created to include only the necessary subset of simulator complexity for a particular scenario. To demonstrate the viability of such an approach we tested it on a popular reactive transport benchmark problem that involves 1D Calcite transport. This is a published benchmark problem (Kolditz, 2012) for simulation models and for this reason we use it to test the surrogate model approach. To do this we tried a number of statistical models available through the caret and DiceEval packages for R, to be used as surrogate models. These were trained on randomly sampled subset of the input-output data from the geochemical simulation model used in the original reactive transport simulation. For validation we use the surrogate model to predict the simulator output using the part of sampled input data that was not used for training the statistical model. For this scenario we find that the multivariate adaptive regression splines

  2. SIMULATION OF COLLECTIVE RISK MODEL

    Directory of Open Access Journals (Sweden)

    Viera Pacáková

    2007-12-01

    Full Text Available The article focuses on providing brief theoretical definitions of the basic terms and methods of modeling and simulations of insurance risks in non-life insurance by means of mathematical and statistical methods using statistical software. While risk assessment of insurance company in connection with its solvency is a rather complex and comprehensible problem, its solution starts with statistical modeling of number and amount of individual claims. Successful solution of these fundamental problems enables solving of curtail problems of insurance such as modeling and simulation of collective risk, premium an reinsurance premium calculation, estimation of probabiliy of ruin etc. The article also presents some essential ideas underlying Monte Carlo methods and their applications to modeling of insurance risk. Solving problem is to find the probability distribution of the collective risk in non-life insurance portfolio. Simulation of the compound distribution function of the aggregate claim amount can be carried out, if the distibution functions of the claim number process and the claim size are assumed given. The Monte Carlo simulation is suitable method to confirm the results of other methods and for treatments of catastrophic claims, when small collectives are studied. Analysis of insurance risks using risk theory is important part of the project Solvency II. Risk theory is analysis of stochastic features of non-life insurance process. The field of application of risk theory has grown rapidly. There is a need to develop the theory into form suitable for practical purposes and demostrate their application. Modern computer simulation techniques open up a wide field of practical applications for risk theory concepts, without requiring the restricive assumptions and sophisticated mathematics. This article presents some comparisons of the traditional actuarial methods and of simulation methods of the collective risk model.

  3. Radiography benchmark 2014

    Energy Technology Data Exchange (ETDEWEB)

    Jaenisch, G.-R., E-mail: Gerd-Ruediger.Jaenisch@bam.de; Deresch, A., E-mail: Gerd-Ruediger.Jaenisch@bam.de; Bellon, C., E-mail: Gerd-Ruediger.Jaenisch@bam.de [Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin (Germany); Schumm, A.; Lucet-Sanchez, F.; Guerin, P. [EDF R and D, 1 avenue du Général de Gaulle, 92141 Clamart (France)

    2015-03-31

    The purpose of the 2014 WFNDEC RT benchmark study was to compare predictions of various models of radiographic techniques, in particular those that predict the contribution of scattered radiation. All calculations were carried out for homogenous materials and a mono-energetic X-ray point source in the energy range between 100 keV and 10 MeV. The calculations were to include the best physics approach available considering electron binding effects. Secondary effects like X-ray fluorescence and bremsstrahlung production were to be taken into account if possible. The problem to be considered had two parts. Part I examined the spectrum and the spatial distribution of radiation behind a single iron plate. Part II considered two equally sized plates, made of iron and aluminum respectively, only evaluating the spatial distribution. Here we present the results of above benchmark study, comparing them to MCNP as the assumed reference model. The possible origins of the observed deviations are discussed.

  4. A BENCHMARKING ANALYSIS FOR FIVE RADIONUCLIDE VADOSE ZONE MODELS (CHAIN, MULTIMED_DP, FECTUZ, HYDRUS, AND CHAIN 2D) IN SOIL SCREENING LEVEL CALCULATIONS

    Science.gov (United States)

    Five radionuclide vadose zone models with different degrees of complexity (CHAIN, MULTIMED_DP, FECTUZ, HYDRUS, and CHAIN 2D) were selected for use in soil screening level (SSL) calculations. A benchmarking analysis between the models was conducted for a radionuclide (99Tc) rele...

  5. Experimental benchmarks and simulation of GAMMA-T for overcooling and undercooling transients in HTGRs coupled with MED desalination plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Sik, E-mail: hskim25@kaist.ac.kr [Korea Advanced Institute of Science and Technology (KAIST), Department of Nuclear and Quantum Engineering, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, In Hun, E-mail: nuclea@kaist.ac.kr [Korea Advanced Institute of Science and Technology (KAIST), Department of Nuclear and Quantum Engineering, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); NO, Hee Cheon, E-mail: hcno@kaist.ac.kr [Korea Advanced Institute of Science and Technology (KAIST), Department of Nuclear and Quantum Engineering, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Jin, Hyung Gon, E-mail: gonijin@gmail.com [Korea Advanced Institute of Science and Technology (KAIST), Department of Nuclear and Quantum Engineering, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2013-06-15

    Highlights: ► The GAMMA-T code was well validated through benchmark experiments. ► Based on the KAIST coupling scheme, the GTHTR300 + MED systems were made. ► Safety analysis was performed for overcooling and undercooling accidents. ► In all accidents, maximum peak fuel temperatures were well below than 1600 °C. ► In all accidents, the HTGR + MED system could be operated continuously. -- Abstracts: The nuclear desalination based on the high temperature gas-cooled reactor (HTGR) with gas turbomachinery and multi-effect distillation (MED) is attracting attention because the coupling system can utilize the waste heat of the nuclear power system for the MED desalination system. In previous work, KAIST proposed the new HTGR + MED coupling scheme, evaluated desalination performance, and performed cost analysis for the system. In this paper, in order to confirm the safety and the performance of the coupling system, we performed the transient analysis with GAMMA-T (GAs Multidimensional Multicomponent mixture Analysis–Turbomachinery) code for the KAIST HTGR + MED systems. The experimental benchmarks of GAMMA-T code were set up before the transient analysis for several accident scenarios. The GAMMA-T code was well validated against steady state and transient scenarios of the He–Water test loop such as changes in water mass flow rate and water inlet temperatures. Then, for transient analysis, the GTHTR300 was chosen as a reference plant. The GTHTR300 + MED systems were made, based on the KAIST HTGR + MED coupling scheme. Transient analysis was performed for three kinds of accidents scenarios: (1) loss of heat rejection through MED plant, (2) loss of heat rejection through heat sink, and (3) overcooling due to abnormal cold temperature of seawater. In all kinds of accident scenarios, maximum peak fuel temperatures were well below than the fuel failure criterion, 1600 °C and the GTHTR300 + MED system could be operated continuously and safely. Specially, in the

  6. MODELLING, SIMULATING AND OPTIMIZING BOILERS

    DEFF Research Database (Denmark)

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

    2003-01-01

    This paper describes the modelling, simulating and optimizing including experimental verification as being carried out as part of a Ph.D. project being written resp. supervised by the authors. The work covers dynamic performance of both water-tube boilers and fire tube boilers. A detailed dynamic...... model of the boiler has been developed and simulations carried out by means of the Matlab integration routines. The model is prepared as a dynamic model consisting of both ordinary differential equations and algebraic equations, together formulated as a Differential-Algebraic-Equation system. Being able...... to operate a boiler plant dynamically means that the boiler designs must be able to absorb any fluctuations in water level and temperature gradients resulting from the pressure change in the boiler. On the one hand a large water-/steam space may be required, i.e. to build the boiler as big as possible. Due...

  7. Modelling, simulating and optimizing Boilers

    DEFF Research Database (Denmark)

    Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels

    2003-01-01

    This paper describes the modelling, simulating and optimizing including experimental verication as being carried out as part of a Ph.D. project being written resp. supervised by the authors. The work covers dynamic performance of both water-tube boilers and re tube boilers. A detailed dynamic model...... of the boiler has been developed and simulations carried out by means of the Matlab integration routines. The model is prepared as a dynamic model consisting of both ordinary differential equations and algebraic equations, together formulated as a Differential-Algebraic- Equation system. Being able to operate...... a boiler plant dynamically means that the boiler designs must be able to absorb any uctuations in water level and temperature gradients resulting from the pressure change in the boiler. On the one hand a large water-/steam space may be required, i.e. to build the boiler as big as possible. Due...

  8. Intelligent Mobility Modeling and Simulation

    Science.gov (United States)

    2015-03-04

    cog.cs.drexel.edu/act-r/index.html) •Models sensory / motor performance of human driver or teleoperator 27UNCLASSIFIED: Distribution Statement A. Approved for...U.S. ARMY TANK AUTOMOTIVE RESEARCH, DEVELOPMENT AND ENGINEERING CENTER Intelligent Mobility Modeling and Simulation 1 Dr. P. Jayakumar, S. Arepally...Prescribed by ANSI Std Z39-18 Contents 1. Mobility - Autonomy - Latency Relationship 2. Machine - Human Partnership 3. Development of Shared Control

  9. Theoretical investigations into the nucleation of silica growth in basic solution part II--derivation and benchmarking of a first principles kinetic model of solution chemistry.

    Science.gov (United States)

    McIntosh, Grant J

    2013-10-28

    A kinetic model of silicate oligomerization in water, up to and including tetramer formation, has been compiled exclusively from rate constants derived from transition state theory based on either quantum chemical data (derived under a hybrid solvation framework) for all bond breaking-forming reactions, or using empirically-based approximated pKa's and diffusion coefficients for rate constants of pH-based and bimolecular steps. The rate constants, based on an exhaustive search of all relevant elementary steps, form the basis of our kinetic model; numerical solution of the resulting rate equations allows the simulation of the reaction system, given a set of initial conditions and with almost no restriction on concentrations, pH, or reaction time, in a matter of only minutes. The model, which we believe contains all possible isomers of both neutral and singly anionic clusters, has been extensively benchmarked and reproduces a number of important experimental observations in the range pH ≈ 4-10. In particular, it provides a good description of the dominant products; product yields and reaction times (also as a function of pH) are in agreement with experiment; the linear relationship between the log of the rate of silica dissolution and pH is well reproduced; the origin of silica scaling naturally arises; and we can also simulate the observed fourth order dependence of the rate of monomer consumption on H4SiO4 concentration. This should be a general approach to exploring solution phase chemistry, and could be a useful complement to more conventional molecular dynamics and Monte Carlo modelling approaches in understanding complex reaction networks in solution.

  10. WIPP Benchmark calculations with the large strain SPECTROM codes

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, G.D.; DeVries, K.L. [RE/SPEC, Inc., Rapid City, SD (United States)

    1995-08-01

    This report provides calculational results from the updated Lagrangian structural finite-element programs SPECTROM-32 and SPECTROM-333 for the purpose of qualifying these codes to perform analyses of structural situations in the Waste Isolation Pilot Plant (WIPP). Results are presented for the Second WIPP Benchmark (Benchmark II) Problems and for a simplified heated room problem used in a parallel design calculation study. The Benchmark II problems consist of an isothermal room problem and a heated room problem. The stratigraphy involves 27 distinct geologic layers including ten clay seams of which four are modeled as frictionless sliding interfaces. The analyses of the Benchmark II problems consider a 10-year simulation period. The evaluation of nine structural codes used in the Benchmark II problems shows that inclusion of finite-strain effects is not as significant as observed for the simplified heated room problem, and a variety of finite-strain and small-strain formulations produced similar results. The simplified heated room problem provides stratigraphic complexity equivalent to the Benchmark II problems but neglects sliding along the clay seams. The simplified heated problem does, however, provide a calculational check case where the small strain-formulation produced room closures about 20 percent greater than those obtained using finite-strain formulations. A discussion is given of each of the solved problems, and the computational results are compared with available published results. In general, the results of the two SPECTROM large strain codes compare favorably with results from other codes used to solve the problems.

  11. Application of structural equation models for evaluating epidemiological data and for calculation of the benchmark dose

    DEFF Research Database (Denmark)

    Budtz-Jørgensen, Esben; Keiding, Niels; Grandjean, P.

    2003-01-01

    observational epidemiology; measurement error; multiple endpoints structural equation models; safety standard......observational epidemiology; measurement error; multiple endpoints structural equation models; safety standard...

  12. Hadron Production Model Developments and Benchmarking in the 0.7 - 12 GeV Energy Region

    CERN Document Server

    Mokhov, N V; Striganov, S I

    2014-01-01

    Driven by the needs of the intensity frontier projects with their Megawatt beams, e.g., ESS, FAIR and Project X, and their experiments, the event generators of the MARS15 code have been recently improved. After thorough analysis and benchmarking against data, including the newest ones by the HARP collaboration, both the exclusive and inclusive particle production models were further developed in the crucial for the above projects - but difficult from a theoretical standpoint - projectile energy region of 0.7 to 12 GeV. At these energies, modelling of prompt particle production in nucleon-nucleon and pion-nucleon inelastic reactions is now based on a combination of phase-space and isobar models. Other reactions are still modeled in the framework of the Quark-Gluon String Model. Pion, kaon and strange particle production and propagation in nuclear media are improved. For the alternative inclusive mode, experimental data on large-angle (> 20 degrees) pion production in hadron-nucleus interactions are parameteriz...

  13. Modeling coupled blast/structure interaction with Zapotec, benchmark calculations for the Conventional Weapon Effects Backfill (CONWEB) tests.

    Energy Technology Data Exchange (ETDEWEB)

    Bessette, Gregory Carl

    2004-09-01

    Modeling the response of buried reinforced concrete structures subjected to close-in detonations of conventional high explosives poses a challenge for a number of reasons. Foremost, there is the potential for coupled interaction between the blast and structure. Coupling enters the problem whenever the structure deformation affects the stress state in the neighboring soil, which in turn, affects the loading on the structure. Additional challenges for numerical modeling include handling disparate degrees of material deformation encountered in the structure and surrounding soil, modeling the structure details (e.g., modeling the concrete with embedded reinforcement, jointed connections, etc.), providing adequate mesh resolution, and characterizing the soil response under blast loading. There are numerous numerical approaches for modeling this class of problem (e.g., coupled finite element/smooth particle hydrodynamics, arbitrary Lagrange-Eulerian methods, etc.). The focus of this work will be the use of a coupled Euler-Lagrange (CEL) solution approach. In particular, the development and application of a CEL capability within the Zapotec code is described. Zapotec links two production codes, CTH and Pronto3D. CTH, an Eulerian shock physics code, performs the Eulerian portion of the calculation, while Pronto3D, an explicit finite element code, performs the Lagrangian portion. The two codes are run concurrently with the appropriate portions of a problem solved on their respective computational domains. Zapotec handles the coupling between the two domains. The application of the CEL methodology within Zapotec for modeling coupled blast/structure interaction will be investigated by a series of benchmark calculations. These benchmarks rely on data from the Conventional Weapons Effects Backfill (CONWEB) test series. In these tests, a 15.4-lb pipe-encased C-4 charge was detonated in soil at a 5-foot standoff from a buried test structure. The test structure was composed of a

  14. Assessment of Molecular Modeling & Simulation

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-01-03

    This report reviews the development and applications of molecular and materials modeling in Europe and Japan in comparison to those in the United States. Topics covered include computational quantum chemistry, molecular simulations by molecular dynamics and Monte Carlo methods, mesoscale modeling of material domains, molecular-structure/macroscale property correlations like QSARs and QSPRs, and related information technologies like informatics and special-purpose molecular-modeling computers. The panel's findings include the following: The United States leads this field in many scientific areas. However, Canada has particular strengths in DFT methods and homogeneous catalysis; Europe in heterogeneous catalysis, mesoscale, and materials modeling; and Japan in materials modeling and special-purpose computing. Major government-industry initiatives are underway in Europe and Japan, notably in multi-scale materials modeling and in development of chemistry-capable ab-initio molecular dynamics codes.

  15. Animal models for simulating weightlessness

    Science.gov (United States)

    Morey-Holton, E.; Wronski, T. J.

    1982-01-01

    NASA has developed a rat model to simulate on earth some aspects of the weightlessness alterations experienced in space, i.e., unloading and fluid shifts. Comparison of data collected from space flight and from the head-down rat suspension model suggests that this model system reproduces many of the physiological alterations induced by space flight. Data from various versions of the rat model are virtually identical for the same parameters; thus, modifications of the model for acute, chronic, or metabolic studies do not alter the results as long as the critical components of the model are maintained, i.e., a cephalad shift of fluids and/or unloading of the rear limbs.

  16. Simulation Tool for Inventory Models: SIMIN

    OpenAIRE

    Pratiksha Saxen; Tulsi Kushwaha

    2014-01-01

    In this paper, an integrated simulation optimization model for the inventory system is developed. An effective algorithm is developed to evaluate and analyze the back-end stored simulation results. This paper proposes simulation tool SIMIN (Inventory Simulation) to simulate inventory models. SIMIN is a tool which simulates and compares the results of different inventory models. To overcome various practical restrictive assumptions, SIMIN provides values for a number of performance measurement...

  17. Benchmarking v ICT

    OpenAIRE

    Blecher, Jan

    2009-01-01

    The aim of this paper is to describe benefits of benchmarking IT in wider context and benchmarking scope at all. I specify benchmarking as a process and mention basic rules and guidelines. Further I define IT benchmarking domains and describe possibilities of their use. Best known type of IT benchmark is cost benchmark which represents only a subset of benchmark opportunities. In this paper, is cost benchmark rather an imaginary first step to benchmarking contribution to company. IT benchmark...

  18. 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.

  19. DSP Platform Benchmarking : DSP Platform Benchmarking

    OpenAIRE

    Xinyuan, Luo

    2009-01-01

    Benchmarking of DSP kernel algorithms was conducted in the thesis on a DSP processor for teaching in the course TESA26 in the department of Electrical Engineering. It includes benchmarking on cycle count and memory usage. The goal of the thesis is to evaluate the quality of a single MAC DSP instruction set and provide suggestions for further improvement in instruction set architecture accordingly. The scope of the thesis is limited to benchmark the processor only based on assembly coding. The...

  20. Benchmark experiments for higher-order and full-Stokes ice sheet models (ISMIP–HOM

    Directory of Open Access Journals (Sweden)

    F. Pattyn

    2008-08-01

    Full Text Available We present the results of the first ice sheet model intercomparison project for higher-order and full-Stokes ice sheet models. These models are compared and verified in a series of six experiments of which one has an analytical solution obtained from a perturbation analysis. The experiments are applied to both 2-D and 3-D geometries; five experiments are steady-state diagnostic, and one has a time-dependent prognostic solution. All participating models give results that are in close agreement. A clear distinction can be made between higher-order models and those that solve the full system of equations. The full-Stokes models show a much smaller spread, hence are in better agreement with one another and with the analytical solution.

  1. Simulation of sound waves using the Lattice Boltzmann Method for fluid flow: Benchmark cases for outdoor sound propagation

    NARCIS (Netherlands)

    Salomons, E.M.; Lohman, W.J.A.; Zhou, H.

    2016-01-01

    Propagation of sound waves in air can be considered as a special case of fluid dynamics. Consequently, the lattice Boltzmann method (LBM) for fluid flow can be used for simulating sound propagation. In this article application of the LBM to sound propagation is illustrated for various cases: free-fi

  2. Photochemistry in Terrestrial Exoplanet Atmospheres I: Photochemistry Model and Benchmark Cases

    OpenAIRE

    2012-01-01

    We present a comprehensive photochemistry model for exploration of the chemical composition of terrestrial exoplanet atmospheres. The photochemistry model is designed from the ground up to have the capacity to treat all types of terrestrial planet atmospheres, ranging from oxidizing through reducing, which makes the code suitable for applications for the wide range of anticipated terrestrial exoplanet compositions. The one-dimensional chemical transport model treats up to 800 chemical reactio...

  3. Benchmark campaign and case study episode in central Europe for development and assessment of advanced GNSS tropospheric models and products

    Science.gov (United States)

    Douša, Jan; Dick, Galina; Kačmařík, Michal; Brožková, Radmila; Zus, Florian; Brenot, Hugues; Stoycheva, Anastasia; Möller, Gregor; Kaplon, Jan

    2016-07-01

    Initial objectives and design of the Benchmark campaign organized within the European COST Action ES1206 (2013-2017) are described in the paper. This campaign has aimed to support the development and validation of advanced Global Navigation Satellite System (GNSS) tropospheric products, in particular high-resolution and ultra-fast zenith total delays (ZTDs) and tropospheric gradients derived from a dense permanent network. A complex data set was collected for the 8-week period when several extreme heavy precipitation episodes occurred in central Europe which caused severe river floods in this area. An initial processing of data sets from GNSS products and numerical weather models (NWMs) provided independently estimated reference parameters - zenith tropospheric delays and tropospheric horizontal gradients. Their provision gave an overview about the product similarities and complementarities, and thus a potential for improvements of a synergy in their optimal exploitations in future. Reference GNSS and NWM results were intercompared and visually analysed using animated maps. ZTDs from two reference GNSS solutions compared to global ERA-Interim reanalysis resulted in accuracy at the 10 mm level in terms of the root mean square (rms) with a negligible overall bias, comparisons to Global Forecast System (GFS) forecasts showed accuracy at the 12 mm level with the overall bias of -5 mm and, finally, comparisons to mesoscale ALADIN-CZ forecast resulted in accuracy at the 8 mm level with a negligible total bias. The comparison of horizontal tropospheric gradients from GNSS and NWM data demonstrated a very good agreement among independent solutions with negligible biases and an accuracy of about 0.5 mm. Visual comparisons of maps of zenith wet delays and tropospheric horizontal gradients showed very promising results for future exploitations of advanced GNSS tropospheric products in meteorological applications, such as severe weather event monitoring and weather nowcasting

  4. Benchmark of CFD Simulations Using Temperatures Measured Within an Enclosed Array of Heater Rods Oriented Vertically and Horizontally

    Science.gov (United States)

    Chalasani, Narayana Rao

    Experiments and computational fluid dynamics/radiation heat transfer simulations of an 8x8 array of heated rods within an aluminum enclosure are performed. This configuration represents a region inside the channel of a spent boiling water reactor (BWR) fuel assembly between two consecutive spacer plates. The heater rods can be oriented horizontally or vertically to represent transport or storage conditions, respectively. The measured and simulated rod-to-wall temperature differences are compared for various heater rod power levels (100, 200, 300, 400 and 500W), gases (Helium and Nitrogen), enclosure wall temperatures, pressures (1, 2 and 3 atm) and orientations (Horizontal and Vertical) to assess the accuracy of the computational fluid dynamics (CFD) code. For analysis of spent nuclear fuel casks, it is crucial to predict the temperature of the hottest rods in an assembly to ensure that none of the fuel cladding exceeds its temperature limit. The measured temperatures are compared to those determined using CFD code to assess the adequacy of the computer code. Simulations show that temperature gradients are much steeper near the enclosure walls than they are near the center of the heater rod array. The measured maximum heater rod temperatures are above the center of heater rod array for nitrogen experiments in both horizontal and vertical orientations, whereas for helium the maximum temperatures are at the center of heater rod array irrespective of the orientation due to the high thermal conductivity of the helium gas. The measured temperatures of rods at symmetric locations are not identical, and the difference is larger for rods close to the enclosure wall than for those far from it. Small but uncontrolled deviations of the rod positions away from the design locations may cause these differences. For 2-inch insulated nitrogen experiment in vertical orientation with 1 atm pressure and a total heater rod power of 500 W, the maximum measured heater rod and enclosure

  5. Research on computer systems benchmarking

    Science.gov (United States)

    Smith, Alan Jay (Principal Investigator)

    1996-01-01

    This grant addresses the topic of research on computer systems benchmarking and is more generally concerned with performance issues in computer systems. This report reviews work in those areas during the period of NASA support under this grant. The bulk of the work performed concerned benchmarking and analysis of CPUs, compilers, caches, and benchmark programs. The first part of this work concerned the issue of benchmark performance prediction. A new approach to benchmarking and machine characterization was reported, using a machine characterizer that measures the performance of a given system in terms of a Fortran abstract machine. Another report focused on analyzing compiler performance. The performance impact of optimization in the context of our methodology for CPU performance characterization was based on the abstract machine model. Benchmark programs are analyzed in another paper. A machine-independent model of program execution was developed to characterize both machine performance and program execution. By merging these machine and program characterizations, execution time can be estimated for arbitrary machine/program combinations. The work was continued into the domain of parallel and vector machines, including the issue of caches in vector processors and multiprocessors. All of the afore-mentioned accomplishments are more specifically summarized in this report, as well as those smaller in magnitude supported by this grant.

  6. Benchmark calculation of no-core Monte Carlo shell model in light nuclei

    CERN Document Server

    Abe, T; Otsuka, T; Shimizu, N; Utsuno, Y; Vary, J P; 10.1063/1.3584062

    2011-01-01

    The Monte Carlo shell model is firstly applied to the calculation of the no-core shell model in light nuclei. The results are compared with those of the full configuration interaction. The agreements between them are within a few % at most.

  7. From Physical Benchmarks to Mental Benchmarks: A Four Dimensions Dynamic Model to Assure the Quality of Instructional Activities in Electronic and Virtual Learning Environments

    Science.gov (United States)

    Ahmed Abdelaziz, Hamdy

    2013-01-01

    The objective of this paper was to develop a four dimensions dynamic model for designing instructional activities appropriate to electronic and virtual learning environments. The suggested model is guided by learning principles of cognitivism, constructivism, and connectivism learning theories in order to help online learners to build and acquire…

  8. Verifying and Validating Simulation Models

    Energy Technology Data Exchange (ETDEWEB)

    Hemez, Francois M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-23

    This presentation is a high-level discussion of the Verification and Validation (V&V) of computational models. Definitions of V&V are given to emphasize that “validation” is never performed in a vacuum; it accounts, instead, for the current state-of-knowledge in the discipline considered. In particular comparisons between physical measurements and numerical predictions should account for their respective sources of uncertainty. The differences between error (bias), aleatoric uncertainty (randomness) and epistemic uncertainty (ignorance, lack-of- knowledge) are briefly discussed. Four types of uncertainty in physics and engineering are discussed: 1) experimental variability, 2) variability and randomness, 3) numerical uncertainty and 4) model-form uncertainty. Statistical sampling methods are available to propagate, and analyze, variability and randomness. Numerical uncertainty originates from the truncation error introduced by the discretization of partial differential equations in time and space. Model-form uncertainty is introduced by assumptions often formulated to render a complex problem more tractable and amenable to modeling and simulation. The discussion concludes with high-level guidance to assess the “credibility” of numerical simulations, which stems from the level of rigor with which these various sources of uncertainty are assessed and quantified.

  9. Simulation of Sound Waves Using the Lattice Boltzmann Method for Fluid Flow: Benchmark Cases for Outdoor Sound Propagation

    OpenAIRE

    Erik M. Salomons; Lohman, Walter J. A.; Han Zhou

    2016-01-01

    Propagation of sound waves in air can be considered as a special case of fluid dynamics. Consequently, the lattice Boltzmann method (LBM) for fluid flow can be used for simulating sound propagation. In this article application of the LBM to sound propagation is illustrated for various cases: free-field propagation, propagation over porous and non-porous ground, propagation over a noise barrier, and propagation in an atmosphere with wind. LBM results are compared with solutions of the equation...

  10. Plasma Waves as a Benchmark Problem

    CERN Document Server

    Kilian, Patrick; Schreiner, Cedric; Spanier, Felix

    2016-01-01

    A large number of wave modes exist in a magnetized plasma. Their properties are determined by the interaction of particles and waves. In a simulation code, the correct treatment of field quantities and particle behavior is essential to correctly reproduce the wave properties. Consequently, plasma waves provide test problems that cover a large fraction of the simulation code. The large number of possible wave modes and the freedom to choose parameters make the selection of test problems time consuming and comparison between different codes difficult. This paper therefore aims to provide a selection of test problems, based on different wave modes and with well defined parameter values, that is accessible to a large number of simulation codes to allow for easy benchmarking and cross validation. Example results are provided for a number of plasma models. For all plasma models and wave modes that are used in the test problems, a mathematical description is provided to clarify notation and avoid possible misunderst...

  11. A simplified benchmark” Stock-Flow Consistent (SFC) post-Keynesian growth model

    OpenAIRE

    Cláudio H. dos Santos; Zezza, Gennaro

    2007-01-01

    Despite being arguably one of the most active areas of research in heterodox macroeconomics, the study of the dynamic properties of stock-flow consistent (SFC) growth models of financially sophisticated economies is still in its early stages. This paper attempts to offer a contribution to this line of research by presenting a simplified Post-Keynesian SFC growth model with well-defined dynamic properties, and using it to shed light on the merits and limitations of the current heterodox SFC li...

  12. 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...

  13. Climate simulations for 1880-2003 with GISS modelE

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, J. [NASA Goddard Inst. for Space Studies, New York, NY (United States)]|[Columbia Univ. Earth Inst., New York, NY (United States); Sato, M.; Kharecha, P.; Nazarenko, L.; Aleinov, I.; Bauer, S.; Chandler, M.; Faluvegi, G.; Jonas, J.; Lerner, J.; Perlwitz, J.; Unger, N.; Zhang, S. [Columbia Univ. Earth Inst., New York, NY (United States); Ruedy, R.; Lo, K.; Cheng, Y.; Oinas, V.; Schmunk, R.; Tausnev, N.; Yao, M. [Sigma Space Partners LLC, New York, NY (United States); Lacis, A.; Schmidt, G.A.; Del Genio, A.; Rind, D.; Romanou, A.; Shindell, D. [NASA Goddard Inst. for Space Studies, New York, NY (United States)]|[Columbia Univ., Dept. of Earth and Environmental Sciences, New York, NY (United States); Miller, R.; Hall, T. [NASA Goddard Inst. for Space Studies, New York, NY (United States)]|[Columbia Univ., Dept. of Applied Physics and Applied Mathematics, New York, NY (United States); Russell, G.; Canuto, V.; Kiang, N.Y. [NASA Goddard Inst. for Space Studies, New York, NY (United States); Baum, E.; Cohen, A. [Clean Air Task Force, Boston, MA (United States); Cairns, B.; Perlwitz, J. [Columbia Univ., Dept. of Applied Physics and Applied Mathematics, New York, NY (United States); Fleming, E.; Jackman, C.; Labow, G. [NASA Goddard Space Flight Center, Greenbelt, MD (United States); Friend, A.; Kelley, M. [Lab. des Sciences du Climat et de l' Environnement, Gif-sur-Yvette (France); Koch, D. [Columbia Univ. Earth Inst., New York, NY (United States)]|[Yale Univ., Dept. of Geology, New Haven, CT (United States); Menon, S.; Novakov, T. [Lawrence Berkeley National Lab., CA (United States); Stone, P. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Sun, S. [NASA Goddard Inst. for Space Studies, New York, NY (United States)]|[Massachusetts Inst. of Tech., Cambridge, MA (United States); Streets, D. [Argonne National Lab., IL (United States); Thresher, D. [Columbia Univ., Dept. of Earth and Environmental Sciences, New York, NY (United States)

    2007-12-15

    We carry out climate simulations for 1880-2003 with GISS modelE driven by ten measured or estimated climate forcings. 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 forcings, observations, unforced variability among model ensemble members, and, if available, observed variability. Discrepancies between observations and simulations with all forcings are due to model deficiencies, inaccurate or incomplete forcings, 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 forcings, we aim to provide a benchmark against which the effect of improvements in the model, climate forcings, and observations can be tested. Principal model deficiencies include unrealistically 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 forcings are the temporal and spatial variations of anthropogenic aerosols and their indirect effects on clouds. (orig.)

  14. MODELLING, SIMULATING AND OPTIMIZING BOILERS

    DEFF Research Database (Denmark)

    Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels

    2004-01-01

    on the boiler) have been dened. Furthermore a number of constraints related to: minimum and maximum boiler load gradient, minimum boiler size, Shrinking and Swelling and Steam Space Load have been dened. For dening the constraints related to the required boiler volume a dynamic model for simulating the boiler...... size. The model has been formulated with a specied building-up of the pressure during the start-up of the plant, i.e. the steam production during start-up of the boiler is output from the model. The steam outputs together with requirements with respect to steam space load have been utilized to dene...... of the boiler is (with an acceptable accuracy) proportional with the volume of the boiler. For the dynamic operation capability a cost function penalizing limited dynamic operation capability and vise-versa has been dened. The main idea is that it by mean of the parameters in this function is possible to t its...

  15. The giant HII region NGC 588 as a benchmark for 2D photoionisation models

    CERN Document Server

    Perez-Montero, Enrique; Relano, Monica; Vilchez, Jose M; Kehrig, Carolina; Morisset, Christophe

    2014-01-01

    We use optical integral field spectroscopy and 8 and 24 micron mid-IR observations of the giant HII region NGC 588 in the disc of M33 as input and constraints for two-dimensional tailor-made photoionisation models. Two different geometrical approaches are followed for the modelling structure: i) Each spatial element of the emitting gas is studied individually using models which assume that the ionisation structure is complete in each element to look for azimuthal variations across gas and dust. ii) A single model is considered, and the two-dimensional structure of the gas and the dust are assumed to be due to the projection of an emitting sphere onto the sky. The models in both assumptions reproduce the radial profiles of Hbeta surface brightness, the observed number of ionising photons, and the strong optical emission-line relative intensities. The first approach produces a constant-density matter-bounded thin shell of variable thickness and dust-to-gas ratio, while the second gives place to a radiation-boun...

  16. Singlet Extensions of the Standard Model at LHC Run 2: Benchmarks and Comparison with the NMSSM

    CERN Document Server

    Costa, Raul; Sampaio, Marco O P; Santos, Rui

    2015-01-01

    The Complex singlet extension of the Standard Model (CxSM) is the simplest extension which provides scenarios for Higgs pair production with different masses. The model has two interesting phases: the dark matter phase, with a Standard Model-like Higgs boson, a new scalar and a dark matter candidate; and the broken phase, with all three neutral scalars mixing. In the latter phase Higgs decays into a pair of two different Higgs bosons are possible. In this study we analyse Higgs-to-Higgs decays in the framework of singlet extensions of the Standard Model (SM), with focus on the CxSM. After demonstrating that scenarios with large rates for such chain decays are possible we perform a comparison between the NMSSM and the CxSM. We find that, based on Higgs-to-Higgs decays, the only possibility to distinguish the two models at the LHC run 2 is through final states with two different scalars. This conclusion builds a strong case for searches for final states with two different scalars at the LHC run 2. Finally, we p...

  17. FROM PHYSICAL BENCHMARKS TO MENTAL BENCHMARKS: A Four Dimensions Dynamic Model to Assure the Quality of Instructional Activities in Electronic and Virtual Learning Environments

    Directory of Open Access Journals (Sweden)

    Hamdy AHMED ABDELAZIZ

    2013-04-01

    Full Text Available The objective of this paper was to develop a four dimensions dynamic model for designing instructional activities appropriate to electronic and virtual learning environments. The suggested model is guided by learning principles of cognitivism, constructivism, and connectivism learning theories in order to help online learners to build and acquire meaningful knowledge and experiences. The proposed model consists of four dynamic dimensions: Ø Cognitive presence activities; Ø Psychological presence activities; Ø Social presence activities; and Ø Mental presence activities. Cognitive presence activities refer to learner’s ability to emerge a cognitive vision regarding the content of learning. The cognitive vision will be the starting point to construct meaningful understanding. Psychological presence activities refer to the learner’s ability to construct self awareness and trustworthiness. It will work as psychological schema to decrease the load of learning at distance. Social presence activities refer to the learner’s ability to share knowledge with others in a way to construct a community of practice and assure global understanding of learning. Finally, mental presence activities refer to learner’s ability to construct mental models that represent knowledge creation. It will help learners to make learning outcomes and experiences transferable. Applying the proposed model will improve the process of developing e-based activities throughout a set of adaptive and dynamic frameworks and guidelines to meet online learner’s cognitive, psychological, social and mental presence.

  18. Benchmarking of numerical models describing the dispersion of radionuclides in the Arctic Seas

    DEFF Research Database (Denmark)

    Scott, E.M.; Gurbutt, P.; Harms, I.

    1997-01-01

    ) development of realistic and reliable assessment models for the dispersal of radioactive contaminants both within, and from, the Arctic ocean; and (2) evaluation of the contributions of different transfer mechanisms to contaminant dispersal and hence, ultimately, to the risks to human health and environment......As part of the International Arctic Seas Assessment Project (IASAP) of the International Atomic Energy Agency (IAEA), a working group was created to model the dispersal and transfer of radionuclides released from radioactive waste disposed of in the Kara Sea. The objectives of this group are: (1...

  19. The results of the pantograph-catenary interaction benchmark

    Science.gov (United States)

    Bruni, Stefano; Ambrosio, Jorge; Carnicero, Alberto; Cho, Yong Hyeon; Finner, Lars; Ikeda, Mitsuru; Kwon, Sam Young; Massat, Jean-Pierre; Stichel, Sebastian; Tur, Manuel; Zhang, Weihua

    2015-03-01

    This paper describes the results of a voluntary benchmark initiative concerning the simulation of pantograph-catenary interaction, which was proposed and coordinated by Politecnico di Milano and participated by 10 research institutions established in 9 different countries across Europe and Asia. The aims of the benchmark are to assess the dispersion of results on the same simulation study cases, to demonstrate the accuracy of numerical methodologies and simulation models and to identify the best suited modelling approaches to study pantograph-catenary interaction. One static and three dynamic simulation cases were defined for a non-existing but realistic high-speed pantograph-catenary couple. These cases were run using 10 of the major simulation codes presently in use for the study of pantograph-catenary interaction, and the results are presented and critically discussed here. All input data required to run the study cases are also provided, allowing the use of this benchmark as a term of comparison for other simulation codes.

  20. Expenditures, Efficiency, and Effectiveness in U.S. Undergraduate Higher Education: A National Benchmark Model

    Science.gov (United States)

    Powell, Brett A.; Gilleland, Diane Suitt; Pearson, L. Carolyn

    2012-01-01

    Institutions of higher education are under pressure to be accountable for their expenditures while demonstrating their effectiveness. Through structural equation modeling, a relationship was found between expenditures and the efficiency and effectiveness of an institution, and an optimal expenditure level was found that maximized an institution's…

  1. Applicability domains for classification problems: benchmarking of distance to models for AMES mutagenicity set

    Science.gov (United States)

    For QSAR and QSPR modeling of biological and physicochemical properties, estimating the accuracy of predictions is a critical problem. The “distance to model” (DM) can be defined as a metric that defines the similarity between the training set molecules and the test set compound ...

  2. Analytical solutions for benchmarking cold regions subsurface water flow and energy transport models: one-dimensional soil thaw with conduction and advection

    Science.gov (United States)

    Kurylyk, Barret L.; McKenzie, Jeffrey M; MacQuarrie, Kerry T. B.; Voss, Clifford I.

    2014-01-01

    Numerous cold regions water flow and energy transport models have emerged in recent years. Dissimilarities often exist in their mathematical formulations and/or numerical solution techniques, but few analytical solutions exist for benchmarking flow and energy transport models that include pore water phase change. This paper presents a detailed derivation of the Lunardini solution, an approximate analytical solution for predicting soil thawing subject to conduction, advection, and phase change. Fifteen thawing scenarios are examined by considering differences in porosity, surface temperature, Darcy velocity, and initial temperature. The accuracy of the Lunardini solution is shown to be proportional to the Stefan number. The analytical solution results obtained for soil thawing scenarios with water flow and advection are compared to those obtained from the finite element model SUTRA. Three problems, two involving the Lunardini solution and one involving the classic Neumann solution, are recommended as standard benchmarks for future model development and testing.

  3. Simulation of Sound Waves Using the Lattice Boltzmann Method for Fluid Flow: Benchmark Cases for Outdoor Sound Propagation.

    Directory of Open Access Journals (Sweden)

    Erik M Salomons

    Full Text Available Propagation of sound waves in air can be considered as a special case of fluid dynamics. Consequently, the lattice Boltzmann method (LBM for fluid flow can be used for simulating sound propagation. In this article application of the LBM to sound propagation is illustrated for various cases: free-field propagation, propagation over porous and non-porous ground, propagation over a noise barrier, and propagation in an atmosphere with wind. LBM results are compared with solutions of the equations of acoustics. It is found that the LBM works well for sound waves, but dissipation of sound waves with the LBM is generally much larger than real dissipation of sound waves in air. To circumvent this problem it is proposed here to use the LBM for assessing the excess sound level, i.e. the difference between the sound level and the free-field sound level. The effect of dissipation on the excess sound level is much smaller than the effect on the sound level, so the LBM can be used to estimate the excess sound level for a non-dissipative atmosphere, which is a useful quantity in atmospheric acoustics. To reduce dissipation in an LBM simulation two approaches are considered: i reduction of the kinematic viscosity and ii reduction of the lattice spacing.

  4. Simulation of Sound Waves Using the Lattice Boltzmann Method for Fluid Flow: Benchmark Cases for Outdoor Sound Propagation.

    Science.gov (United States)

    Salomons, Erik M; Lohman, Walter J A; Zhou, Han

    2016-01-01

    Propagation of sound waves in air can be considered as a special case of fluid dynamics. Consequently, the lattice Boltzmann method (LBM) for fluid flow can be used for simulating sound propagation. In this article application of the LBM to sound propagation is illustrated for various cases: free-field propagation, propagation over porous and non-porous ground, propagation over a noise barrier, and propagation in an atmosphere with wind. LBM results are compared with solutions of the equations of acoustics. It is found that the LBM works well for sound waves, but dissipation of sound waves with the LBM is generally much larger than real dissipation of sound waves in air. To circumvent this problem it is proposed here to use the LBM for assessing the excess sound level, i.e. the difference between the sound level and the free-field sound level. The effect of dissipation on the excess sound level is much smaller than the effect on the sound level, so the LBM can be used to estimate the excess sound level for a non-dissipative atmosphere, which is a useful quantity in atmospheric acoustics. To reduce dissipation in an LBM simulation two approaches are considered: i) reduction of the kinematic viscosity and ii) reduction of the lattice spacing.

  5. Uterine Contraction Modeling and Simulation

    Science.gov (United States)

    Liu, Miao; Belfore, Lee A.; Shen, Yuzhong; Scerbo, Mark W.

    2010-01-01

    Building a training system for medical personnel to properly interpret fetal heart rate tracing requires developing accurate models that can relate various signal patterns to certain pathologies. In addition to modeling the fetal heart rate signal itself, the change of uterine pressure that bears strong relation to fetal heart rate and provides indications of maternal and fetal status should also be considered. In this work, we have developed a group of parametric models to simulate uterine contractions during labor and delivery. Through analysis of real patient records, we propose to model uterine contraction signals by three major components: regular contractions, impulsive noise caused by fetal movements, and low amplitude noise invoked by maternal breathing and measuring apparatus. The regular contractions are modeled by an asymmetric generalized Gaussian function and least squares estimation is used to compute the parameter values of the asymmetric generalized Gaussian function based on uterine contractions of real patients. Regular contractions are detected based on thresholding and derivative analysis of uterine contractions. Impulsive noise caused by fetal movements and low amplitude noise by maternal breathing and measuring apparatus are modeled by rational polynomial functions and Perlin noise, respectively. Experiment results show the synthesized uterine contractions can mimic the real uterine contractions realistically, demonstrating the effectiveness of the proposed algorithm.

  6. Dose-response modeling : Evaluation, application, and development of procedures for benchmark dose analysis in health risk assessment of chemical substances

    OpenAIRE

    Sand, Salomon

    2005-01-01

    In this thesis, dose-response modeling and procedures for benchmark dose (BMD) analysis in health risk assessment of chemical substances have been investigated. The BMD method has been proposed as an alternative to the NOAEL (no-observedadverse- effect-level) approach in health risk assessment of non-genotoxic agents. According to the BMD concept, a dose-response model is fitted to data and the BMD is defined as the dose causing a predetermined change in response. A lowe...

  7. Aquatic Life Benchmarks

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Aquatic Life Benchmarks is an EPA-developed set of criteria for freshwater species. These benchmarks are based on toxicity values reviewed by EPA and used in the...

  8. Title: Benchmark of the radiation field simulations of the LHC injection lines with the RadMon detectors

    CERN Document Server

    Boccone, V; Kramer, D; Roeed, K

    2011-01-01

    In this paper we present the high energy hadron (HEH) fluence simulations in the LHC injection regions (TI2 and TI8) performed by the FLUKA Monte-Carlo code and we compare the expected nominal single event upset (SEU) counts in the RadMon detectors with the measured values. During the LHC injection setup the 450 GeV/c proton beam from the Super Proton Synchrotron (SPS) is progressively adjusted and aligned through the two injection lines until the LHC septum magnets. During the first phase of alignment the beam is dumped onto the injection line dumps TEDs and the debris of the interactions streams trough junction tunnel which contains sensitive electronic equipment. In the case of the TI8 injection lines also the losses on the TCDIH.87904 collimator might represent a problem for the electronics in the UJ87 tunnel.

  9. A Uranium Bioremediation Reactive Transport Benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Yabusaki, Steven B.; Sengor, Sevinc; Fang, Yilin

    2015-06-01

    A reactive transport benchmark problem set has been developed based on in situ uranium bio-immobilization experiments that have been performed at a former uranium mill tailings site in Rifle, Colorado, USA. Acetate-amended groundwater stimulates indigenous microorganisms to catalyze the reduction of U(VI) to a sparingly soluble U(IV) mineral. The interplay between the flow, acetate loading periods and rates, microbially-mediated and geochemical reactions leads to dynamic behavior in metal- and sulfate-reducing bacteria, pH, alkalinity, and reactive mineral surfaces. The benchmark is based on an 8.5 m long one-dimensional model domain with constant saturated flow and uniform porosity. The 159-day simulation introduces acetate and bromide through the upgradient boundary in 14-day and 85-day pulses separated by a 10 day interruption. Acetate loading is tripled during the second pulse, which is followed by a 50 day recovery period. Terminal electron accepting processes for goethite, phyllosilicate Fe(III), U(VI), and sulfate are modeled using Monod-type rate laws. Major ion geochemistry modeled includes mineral reactions, as well as aqueous and surface complexation reactions for UO2++, Fe++, and H+. In addition to the dynamics imparted by the transport of the acetate pulses, U(VI) behavior involves the interplay between bioreduction, which is dependent on acetate availability, and speciation-controlled surface complexation, which is dependent on pH, alkalinity and available surface complexation sites. The general difficulty of this benchmark is the large number of reactions (74), multiple rate law formulations, a multisite uranium surface complexation model, and the strong interdependency and sensitivity of the reaction processes. Results are presented for three simulators: HYDROGEOCHEM, PHT3D, and PHREEQC.

  10. Assessment of CTF Boiling Transition and Critical Heat Flux Modeling Capabilities Using the OECD/NRC BFBT and PSBT Benchmark Databases

    Directory of Open Access Journals (Sweden)

    Maria Avramova

    2013-01-01

    Full Text Available Over the last few years, the Pennsylvania State University (PSU under the sponsorship of the US Nuclear Regulatory Commission (NRC has prepared, organized, conducted, and summarized two international benchmarks based on the NUPEC data—the OECD/NRC Full-Size Fine-Mesh Bundle Test (BFBT Benchmark and the OECD/NRC PWR Sub-Channel and Bundle Test (PSBT Benchmark. The benchmarks’ activities have been conducted in cooperation with the Nuclear Energy Agency/Organization for Economic Co-operation and Development (NEA/OECD and the Japan Nuclear Energy Safety (JNES Organization. This paper presents an application of the joint Penn State University/Technical University of Madrid (UPM version of the well-known sub-channel code COBRA-TF (Coolant Boiling in Rod Array-Two Fluid, namely, CTF, to the steady state critical power and departure from nucleate boiling (DNB exercises of the OECD/NRC BFBT and PSBT benchmarks. The goal is two-fold: firstly, to assess these models and to examine their strengths and weaknesses; and secondly, to identify the areas for improvement.

  11. Benchmarking a DSP processor

    OpenAIRE

    Lennartsson, Per; Nordlander, Lars

    2002-01-01

    This Master thesis describes the benchmarking of a DSP processor. Benchmarking means measuring the performance in some way. In this report, we have focused on the number of instruction cycles needed to execute certain algorithms. The algorithms we have used in the benchmark are all very common in signal processing today. The results we have reached in this thesis have been compared to benchmarks for other processors, performed by Berkeley Design Technology, Inc. The algorithms were programm...

  12. SWEEPOP a simulation model for Target Simulation Mode minesweeping

    NARCIS (Netherlands)

    Keus, H.E.; Beckers, A.L.D.; Cleophas, P.L.H.

    2005-01-01

    SWEEPOP is a flexible model that simulates the physical interaction between objects in a maritime underwater environment. The model was built to analyse the deployment and the performance of a Target Simulation Mode (TSM) minesweeping system for the Royal Netherlands Navy (RNLN) and to support its p

  13. 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.

  14. Benchmarking binary classification models on data sets with different degrees of imbalance

    Institute of Scientific and Technical Information of China (English)

    Ligang ZHOU; Kin Keung LAI

    2009-01-01

    In practice, there are many binary classification problems, such as credit risk assessment, medical testing for determining if a patient has a certain disease or not, etc.However, different problems have different characteristics that may lead to different difficulties of the problem. One important characteristic is the degree of imbalance of two classes in data sets. For data sets with different degrees of imbalance, fire the commonly used binary classification methods still feasible? In this study, various binary classifi-cation models, including traditional statistical methods andnewly emerged methods from artificial intelligence, such as linear regression, discriminant analysis, decision tree, neural network, support vector machines, etc., are reviewed, and their performance in terms of the measure of classification accuracy and area under Receiver Operating Characteristic (ROC) curve are tested and compared on fourteen data sets with different imbalance degrees. The results help to select the appropriate methods for problems with different degrees of imbalance.

  15. Properties of potential modelling three benchmarks: the cosmological constant, inflation and three generations

    CERN Document Server

    Kiselev, V V

    2010-01-01

    We argue for a model of low-energy correction to the inflationary potential as caused by the gauge-mediated breaking down the supersymmetry at the scale of $\\mu_\\textsc{x}\\sim 10^4$ GeV, that provides us with the seesaw mechanism of thin domain wall fluctuations in the flat vacuum. The fluctuations are responsible for the vacuum with the cosmological constant at the scale of $\\mu_\\Lambda\\sim 10^{-2}$ eV suppressed by the Planckian mass $m_\\mathtt{Pl}$ via $\\mu_\\Lambda\\sim\\mu_\\textsc{x}^2/m_\\mathtt{Pl}$. The appropriate vacuum state is occupied after the inflation with quartic coupling constant $\\lambda\\sim\\mu_\\textsc{x}/m_\\mathtt{Pl}\\sim 10^{-14}$ inherently related with the bare mass scale of $\\widetilde m\\sim\\sqrt{\\mu_\\textsc{x}m_\\mathtt{Pl}}\\sim 10^{12}$ GeV determining the thickness of domain walls $\\delta r\\sim1/\\widetilde m$. Such the parameters of potential are still marginally consistent with the observed inhomogeneity of matter density in the Universe. The inflationary evolution suggests the vacuum s...

  16. Weight restrictions on geography variables in the DEA benchmarking model for Norwegian electricity distribution companies

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerndal, Endre; Bjoerndal, Mette; Camanho, Ana

    2008-07-01

    The DEA model for the distribution networks is designed to take into account the diverse operating conditions of the companies through so-called 'geography' variables. Our analyses show that companies with difficult operating conditions tend to be rewarded with relatively high efficiency scores, and this is the reason for introducing weight restrictions. We discuss the relative price restrictions suggested for geography and high voltage variables by NVE (2008), and we compare these to an alternative approach by which the total (virtual) weight of the geography variables is restricted. The main difference between the two approaches is that the former tends to affect more companies, but to a lesser extent, than the latter. We also discuss how to set the restriction limits. Since the virtual restrictions are at a more aggregated level than the relative ones, it may be easier to establish the limits with this approach. Finally, we discuss implementation issues, and give a short overview of available software. (Author). 18 refs., figs

  17. Modern multicore and manycore architectures: Modelling, optimisation and benchmarking a multiblock CFD code

    Science.gov (United States)

    Hadade, Ioan; di Mare, Luca

    2016-08-01

    Modern multicore and manycore processors exhibit multiple levels of parallelism through a wide range of architectural features such as SIMD for data parallel execution or threads for core parallelism. The exploitation of multi-level parallelism is therefore crucial for achieving superior performance on current and future processors. This paper presents the performance tuning of a multiblock CFD solver on Intel SandyBridge and Haswell multicore CPUs and the Intel Xeon Phi Knights Corner coprocessor. Code optimisations have been applied on two computational kernels exhibiting different computational patterns: the update of flow variables and the evaluation of the Roe numerical fluxes. We discuss at great length the code transformations required for achieving efficient SIMD computations for both kernels across the selected devices including SIMD shuffles and transpositions for flux stencil computations and global memory transformations. Core parallelism is expressed through threading based on a number of domain decomposition techniques together with optimisations pertaining to alleviating NUMA effects found in multi-socket compute nodes. Results are correlated with the Roofline performance model in order to assert their efficiency for each distinct architecture. We report significant speedups for single thread execution across both kernels: 2-5X on the multicore CPUs and 14-23X on the Xeon Phi coprocessor. Computations at full node and chip concurrency deliver a factor of three speedup on the multicore processors and up to 24X on the Xeon Phi manycore coprocessor.

  18. Benchmarking the invariant embedding method against analytical solutions in model transport problems

    Directory of Open Access Journals (Sweden)

    Wahlberg Malin

    2006-01-01

    Full Text Available The purpose of this paper is to demonstrate the use of the invariant embedding method in a few model transport problems for which it is also possible to obtain an analytical solution. The use of the method is demonstrated in three different areas. The first is the calculation of the energy spectrum of sputtered particles from a scattering medium without absorption, where the multiplication (particle cascade is generated by recoil production. Both constant and energy dependent cross-sections with a power law dependence were treated. The second application concerns the calculation of the path length distribution of reflected particles from a medium without multiplication. This is a relatively novel application, since the embedding equations do not resolve the depth variable. The third application concerns the demonstration that solutions in an infinite medium and in a half-space are interrelated through embedding-like integral equations, by the solution of which the flux reflected from a half-space can be reconstructed from solutions in an infinite medium or vice versa. In all cases, the invariant embedding method proved to be robust, fast, and monotonically converging to the exact solutions.

  19. A fast and flexible reactor physics model for simulating neutron spectra and depletion in fast reactors

    Science.gov (United States)

    Recktenwald, Geoff; Deinert, Mark

    2010-03-01

    Determining the time dependent concentration of isotopes within a nuclear reactor core is central to the analysis of nuclear fuel cycles. We present a fast, flexible tool for determining the time dependent neutron spectrum within fast reactors. The code (VBUDS: visualization, burnup, depletion and spectra) uses a two region, multigroup collision probability model to simulate the energy dependent neutron flux and tracks the buildup and burnout of 24 actinides, as well as fission products. While originally developed for LWR simulations, the model is shown to produce fast reactor spectra that show high degree of fidelity to available fast reactor benchmarks.

  20. Techniques and Simulation Models in Risk Management

    OpenAIRE

    Mirela GHEORGHE

    2012-01-01

    In the present paper, the scientific approach of the research starts from the theoretical framework of the simulation concept and then continues in the setting of the practical reality, thus providing simulation models for a broad range of inherent risks specific to any organization and simulation of those models, using the informatics instrument @Risk (Palisade). The reason behind this research lies in the need for simulation models that will allow the person in charge with decision taking i...

  1. Benchmarking semantic web technology

    CERN Document Server

    García-Castro, R

    2009-01-01

    This book addresses the problem of benchmarking Semantic Web Technologies; first, from a methodological point of view, proposing a general methodology to follow in benchmarking activities over Semantic Web Technologies and, second, from a practical point of view, presenting two international benchmarking activities that involved benchmarking the interoperability of Semantic Web technologies using RDF(S) as the interchange language in one activity and OWL in the other.The book presents in detail how the different resources needed for these interoperability benchmarking activities were defined:

  2. Benchmarking concentrating photovoltaic systems

    Science.gov (United States)

    Duerr, Fabian; Muthirayan, Buvaneshwari; Meuret, Youri; Thienpont, Hugo

    2010-08-01

    Integral to photovoltaics is the need to provide improved economic viability. To achieve this goal, photovoltaic technology has to be able to harness more light at less cost. A large variety of concentrating photovoltaic concepts has provided cause for pursuit. To obtain a detailed profitability analysis, a flexible evaluation is crucial for benchmarking the cost-performance of this variety of concentrating photovoltaic concepts. To save time and capital, a way to estimate the cost-performance of a complete solar energy system is to use computer aided modeling. In this work a benchmark tool is introduced based on a modular programming concept. The overall implementation is done in MATLAB whereas Advanced Systems Analysis Program (ASAP) is used for ray tracing calculations. This allows for a flexible and extendable structuring of all important modules, namely an advanced source modeling including time and local dependence, and an advanced optical system analysis of various optical designs to obtain an evaluation of the figure of merit. An important figure of merit: the energy yield for a given photovoltaic system at a geographical position over a specific period, can be calculated.

  3. Benchmarking in University Toolbox

    Directory of Open Access Journals (Sweden)

    Katarzyna Kuźmicz

    2015-06-01

    Full Text Available In the face of global competition and rising challenges that higher education institutions (HEIs meet, it is imperative to increase innovativeness and efficiency of their management. Benchmarking can be the appropriate tool to search for a point of reference necessary to assess institution’s competitive position and learn from the best in order to improve. The primary purpose of the paper is to present in-depth analysis of benchmarking application in HEIs worldwide. The study involves indicating premises of using benchmarking in HEIs. It also contains detailed examination of types, approaches and scope of benchmarking initiatives. The thorough insight of benchmarking applications enabled developing classification of benchmarking undertakings in HEIs. The paper includes review of the most recent benchmarking projects and relating them to the classification according to the elaborated criteria (geographical range, scope, type of data, subject, support and continuity. The presented examples were chosen in order to exemplify different approaches to benchmarking in higher education setting. The study was performed on the basis of the published reports from benchmarking projects, scientific literature and the experience of the author from the active participation in benchmarking projects. The paper concludes with recommendations for university managers undertaking benchmarking, derived on the basis of the conducted analysis.

  4. Bridging experiments, models and simulations

    DEFF Research Database (Denmark)

    Carusi, Annamaria; Burrage, Kevin; Rodríguez, Blanca

    2012-01-01

    Computational models in physiology often integrate functional and structural information from a large range of spatiotemporal scales from the ionic to the whole organ level. Their sophistication raises both expectations and skepticism concerning how computational methods can improve our understan...... that contributes to defining the specific aspects of cardiac electrophysiology the MSE system targets, rather than being only an external test, and that this is driven by advances in experimental and computational methods and the combination of both....... of biovariability; 2) testing and developing robust techniques and tools as a prerequisite to conducting physiological investigations; 3) defining and adopting standards to facilitate the interoperability of experiments, models, and simulations; 4) and understanding physiological validation as an iterative process...... understanding of living organisms and also how they can reduce, replace, and refine animal experiments. A fundamental requirement to fulfill these expectations and achieve the full potential of computational physiology is a clear understanding of what models represent and how they can be validated. The present...

  5. Benchmarking and Modeling of a Conventional Mid-Size Car Using ALPHA (SAE Paper 2015-01-1140)

    Science.gov (United States)

    The Advanced Light-Duty Powertrain and Hybrid Analysis (ALPHA) modeling tool was created by EPA to estimate greenhouse gas (GHG) emissions of light-duty vehicles. ALPHA is a physics-based, forward-looking, full vehicle computer simulation capable of analyzing various vehicle type...

  6. Evaluation and comparison of benchmark QSAR models to predict a relevant REACH endpoint: The bioconcentration factor (BCF)

    Energy Technology Data Exchange (ETDEWEB)

    Gissi, Andrea [Laboratory of Environmental Chemistry and Toxicology, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via La Masa 19, 20156 Milano (Italy); Dipartimento di Farmacia – Scienze del Farmaco, Università degli Studi di Bari “Aldo Moro”, Via E. Orabona 4, 70125 Bari (Italy); Lombardo, Anna; Roncaglioni, Alessandra [Laboratory of Environmental Chemistry and Toxicology, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via La Masa 19, 20156 Milano (Italy); Gadaleta, Domenico [Laboratory of Environmental Chemistry and Toxicology, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via La Masa 19, 20156 Milano (Italy); Dipartimento di Farmacia – Scienze del Farmaco, Università degli Studi di Bari “Aldo Moro”, Via E. Orabona 4, 70125 Bari (Italy); Mangiatordi, Giuseppe Felice; Nicolotti, Orazio [Dipartimento di Farmacia – Scienze del Farmaco, Università degli Studi di Bari “Aldo Moro”, Via E. Orabona 4, 70125 Bari (Italy); Benfenati, Emilio, E-mail: emilio.benfenati@marionegri.it [Laboratory of Environmental Chemistry and Toxicology, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via La Masa 19, 20156 Milano (Italy)

    2015-02-15

    regression (R{sup 2}=0.85) and sensitivity (average>0.70) for new compounds in the AD but not present in the training set. However, no single optimal model exists and, thus, it would be wise a case-by-case assessment. Yet, integrating the wealth of information from multiple models remains the winner approach. - Highlights: • REACH encourages the use of in silico methods in the assessment of chemicals safety. • The performances of nine BCF models were evaluated on a benchmark database of 851 chemicals. • We compared the models on the basis of both regression and classification performance. • Statistics on chemicals out of the training set and/or within the applicability domain were compiled. • The results show that QSAR models are useful as weight-of-evidence in support to other methods.

  7. Analysis of the Numerical Diffusion in Anisotropic Mediums: Benchmarks for Magnetic Field Aligned Meshes in Space Propulsion Simulations

    Directory of Open Access Journals (Sweden)

    Daniel Pérez-Grande

    2016-11-01

    Full Text Available This manuscript explores numerical errors in highly anisotropic diffusion problems. First, the paper addresses the use of regular structured meshes in numerical solutions versus meshes aligned with the preferential directions of the problem. Numerical diffusion in structured meshes is quantified by solving the classical anisotropic diffusion problem; the analysis is exemplified with the application to a numerical model of conducting fluids under magnetic confinement, where rates of transport in directions parallel and perpendicular to a magnetic field are quite different. Numerical diffusion errors in this problem promote the use of magnetic field aligned meshes (MFAM. The generation of this type of meshes presents some challenges; several meshing strategies are implemented and analyzed in order to provide insight into achieving acceptable mesh regularity. Second, Gradient Reconstruction methods for magnetically aligned meshes are addressed and numerical errors are compared for the structured and magnetically aligned meshes. It is concluded that using the latter provides a more correct and straightforward approach to solving problems where anisotropicity is present, especially, if the anisotropicity level is high or difficult to quantify. The conclusions of the study may be extrapolated to the study of anisotropic flows different from conducting fluids.

  8. Application of the coupled code COBAYA3/SUBCHANFLOW to the simulation of the Exercise 2 of the OECD/NEA Kalinin-3 Benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, J.; Calleja, M.; Sanchez, V.

    2013-07-01

    The OECD/NEA Kalinin-3 Coolant Transient Benchmark is based on a real transient test that took place on 2nd October 2005 in the Unit 3 of the Russian Kalinin NPP. The reactor type is a VVER-1000/320 and the transient was caused by the intentional switching-off of one of the four operating main coolant pumps at nominal reactor power. A big amount of data was recorded during the transient by the core monitoring system. These data have been made available to the international community through an OECD/NEA benchmark. Thanks to the good quality of the data available, this benchmark is very useful for the validation of coupled neutron kinetics and thermal-hydraulic codes. This paper describes the results obtained with the 3D neutron diffusion code COBAYA3 coupled with the sub-channel thermal-hydraulic code SUBCHANFLOW for the Exercise 2 of the Kalinin-3 Benchmark.

  9. Benchmark Dose Modeling

    Science.gov (United States)

    Finite doses are employed in experimental toxicology studies. Under the traditional methodology, the point of departure (POD) value for low dose extrapolation is identified as one of these doses. Dose spacing necessarily precludes a more accurate description of the POD value. ...

  10. Distributed simulation a model driven engineering approach

    CERN Document Server

    Topçu, Okan; Oğuztüzün, Halit; Yilmaz, Levent

    2016-01-01

    Backed by substantive case studies, the novel approach to software engineering for distributed simulation outlined in this text demonstrates the potent synergies between model-driven techniques, simulation, intelligent agents, and computer systems development.

  11. Radiation Detection Computational Benchmark Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Shaver, Mark W.; Casella, Andrew M.; Wittman, Richard S.; McDonald, Ben S.

    2013-09-24

    Modeling forms an important component of radiation detection development, allowing for testing of new detector designs, evaluation of existing equipment against a wide variety of potential threat sources, and assessing operation performance of radiation detection systems. This can, however, result in large and complex scenarios which are time consuming to model. A variety of approaches to radiation transport modeling exist with complementary strengths and weaknesses for different problems. This variety of approaches, and the development of promising new tools (such as ORNL’s ADVANTG) which combine benefits of multiple approaches, illustrates the need for a means of evaluating or comparing different techniques for radiation detection problems. This report presents a set of 9 benchmark problems for comparing different types of radiation transport calculations, identifying appropriate tools for classes of problems, and testing and guiding the development of new methods. The benchmarks were drawn primarily from existing or previous calculations with a preference for scenarios which include experimental data, or otherwise have results with a high level of confidence, are non-sensitive, and represent problem sets of interest to NA-22. From a technical perspective, the benchmarks were chosen to span a range of difficulty and to include gamma transport, neutron transport, or both and represent different important physical processes and a range of sensitivity to angular or energy fidelity. Following benchmark identification, existing information about geometry, measurements, and previous calculations were assembled. Monte Carlo results (MCNP decks) were reviewed or created and re-run in order to attain accurate computational times and to verify agreement with experimental data, when present. Benchmark information was then conveyed to ORNL in order to guide testing and development of hybrid calculations. The results of those ADVANTG calculations were then sent to PNNL for

  12. Benchmarking water productivity in agriculture and the scope for improvement - remote sensing modelling from field to global scale

    NARCIS (Netherlands)

    Zwart, S.J.

    2010-01-01

    Agriculture is the largest consumer and water. In the context of an increasing population and less water available for the agricultural sector, the water productivity needs to be sustained or increased to secure food security. This study provides benchmark values for water productivity for the major

  13. 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).

  14. 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.

  15. A physiological production model for cacao : results of model simulations

    NARCIS (Netherlands)

    Zuidema, P.A.; Leffelaar, P.A.

    2002-01-01

    CASE2 is a physiological model for cocoa (Theobroma cacao L.) growth and yield. This report introduces the CAcao Simulation Engine for water-limited production in a non-technical way and presents simulation results obtained with the model.

  16. 考虑基准资产的动态投资组合选取%A Dynamic Model of Portfolio Choice with Benchmark Orientation

    Institute of Scientific and Technical Information of China (English)

    郭文英

    2013-01-01

    职业基金经理的目标经常是希望自己的投资组合以稳定的表现能够超越所某一基准资产或组合。因此本文给出一个考虑基准资产的动态均值---方差投资组合选取模型。假设状态之间的转移遵循马氏过程,给定状态转移矩阵,可以得到对风险资产最优投入的解析表达式。此表达式表明对风险资产的投入由三项构成,前两项是不考虑基准资产时对风险资产的投入,最后一项与基准资产有关;在基准资产上的权重由基准资产收益的大小来决定,与积极投资组合管理者的风险厌恶程度无关;随着风险厌恶程度的增加,管理者会减少在风险资产上的投入。数值分析显示考虑基准资产的投资组合是一个积极的投资组合。%Professional fund managers' goals are often hope that their portfolios to stable performance can go beyond a certain benchmark asset or portfolio. So in this paper, we give a dynamic mean-variance considering benchmark asset portfolio selection model. Assumes that the state transfer between follow markov process, a given state transition matrix, can get analytic expressions of the optimal risk assets. This expression shows that investment in risky assets is composed of three , the first two benchmark is not consider assets for risky assets into, when the last item related to benchmark asset. On the baseline assets are weighted by benchmark yields to decide the size of the assets, has nothing to do with the degree of risk aversion of the active portfolio managers. With the increase of degree of risk aversion, risk managers will reduce the asset to hurt. Portfolios of numerical analysis shows that considering the benchmark portfolio is a positive.

  17. Nonsmooth Modeling and Simulation for Switched Circuits

    CERN Document Server

    Acary, Vincent; Brogliato, Bernard

    2011-01-01

    "Nonsmooth Modeling and Simulation for Switched Circuits" concerns the modeling and the numerical simulation of switched circuits with the nonsmooth dynamical systems (NSDS) approach, using piecewise-linear and multivalued models of electronic devices like diodes, transistors, switches. Numerous examples (ranging from introductory academic circuits to various types of power converters) are analyzed and many simulation results obtained with the INRIA open-source SICONOS software package are presented. Comparisons with SPICE and hybrid methods demonstrate the power of the NSDS approach

  18. Juno model rheometry and simulation

    Science.gov (United States)

    Sampl, Manfred; Macher, Wolfgang; Oswald, Thomas; Plettemeier, Dirk; Rucker, Helmut O.; Kurth, William S.

    2016-10-01

    The experiment Waves aboard the Juno spacecraft, which will arrive at its target planet Jupiter in 2016, was devised to study the plasma and radio waves of the Jovian magnetosphere. We analyzed the Waves antennas, which consist of two nonparallel monopoles operated as a dipole. For this investigation we applied two independent methods: the experimental technique, rheometry, which is based on a downscaled model of the spacecraft to measure the antenna properties in an electrolytic tank and numerical simulations, based on commercial computer codes, from which the quantities of interest (antenna impedances and effective length vectors) are calculated. In this article we focus on the results for the low-frequency range up to about 4 MHz, where the antenna system is in the quasi-static regime. Our findings show that there is a significant deviation of the effective length vectors from the physical monopole directions, caused by the presence of the conducting spacecraft body. The effective axes of the antenna monopoles are offset from the mechanical axes by more than 30°, and effective lengths show a reduction to about 60% of the antenna rod lengths. The antennas' mutual capacitances are small compared to the self-capacitances, and the latter are almost the same for the two monopoles. The overall performance of the antennas in dipole configuration is very stable throughout the frequency range up to about 4-5 MHz and therefore can be regarded as the upper frequency bound below which the presented quasi-static results are applicable.

  19. 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...

  20. The Conic Benchmark Format

    DEFF Research Database (Denmark)

    Friberg, Henrik A.

    This document constitutes the technical reference manual of the Conic Benchmark Format with le extension: .cbf or .CBF. It unies linear, second-order cone (also known as conic quadratic) and semidenite optimization with mixed-integer variables. The format has been designed with benchmark libraries...... in mind, and therefore focuses on compact and easily parsable representations. The problem structure is separated from the problem data, and the format moreover facilitate benchmarking of hotstart capability through sequences of changes....

  1. 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

  2. Energies and 2'-Hydroxyl Group Orientations of RNA Backbone Conformations. Benchmark CCSD(T)/CBS Database, Electronic Analysis, and Assessment of DFT Methods and MD Simulations.

    Science.gov (United States)

    Mládek, Arnošt; Banáš, Pavel; Jurečka, Petr; Otyepka, Michal; Zgarbová, Marie; Šponer, Jiří

    2014-01-14

    Sugar-phosphate backbone is an electronically complex molecular segment imparting RNA molecules high flexibility and architectonic heterogeneity necessary for their biological functions. The structural variability of RNA molecules is amplified by the presence of the 2'-hydroxyl group, capable of forming multitude of intra- and intermolecular interactions. Bioinformatics studies based on X-ray structure database revealed that RNA backbone samples at least 46 substates known as rotameric families. The present study provides a comprehensive analysis of RNA backbone conformational preferences and 2'-hydroxyl group orientations. First, we create a benchmark database of estimated CCSD(T)/CBS relative energies of all rotameric families and test performance of dispersion-corrected DFT-D3 methods and molecular mechanics in vacuum and in continuum solvent. The performance of the DFT-D3 methods is in general quite satisfactory. The B-LYP-D3 method provides the best trade-off between accuracy and computational demands. B3-LYP-D3 slightly outperforms the new PW6B95-D3 and MPW1B95-D3 and is the second most accurate density functional of the study. The best agreement with CCSD(T)/CBS is provided by DSD-B-LYP-D3 double-hybrid functional, although its large-scale applications may be limited by high computational costs. Molecular mechanics does not reproduce the fine energy differences between the RNA backbone substates. We also demonstrate that the differences in the magnitude of the hyperconjugation effect do not correlate with the energy ranking of the backbone conformations. Further, we investigated the 2'-hydroxyl group orientation preferences. For all families, we conducted a QM and MM hydroxyl group rigid scan in gas phase and solvent. We then carried out set of explicit solvent MD simulations of folded RNAs and analyze 2'-hydroxyl group orientations of different backbone families in MD. The solvent energy profiles determined primarily by the sugar pucker match well with the

  3. A Consumer's Guide to Benchmark Dose Models: Results of U.S. EPA Testing of 14 Dichotomous, 8 Continuous, and 6 Developmental Models (Presentation)

    Science.gov (United States)

    Benchmark dose risk assessment software (BMDS) was designed by EPA to generate dose-response curves and facilitate the analysis, interpretation and synthesis of toxicological data. Partial results of QA/QC testing of the EPA benchmark dose software (BMDS) are presented. BMDS pr...

  4. Benchmarking Variable Selection in QSAR.

    Science.gov (United States)

    Eklund, Martin; Norinder, Ulf; Boyer, Scott; Carlsson, Lars

    2012-02-01

    Variable selection is important in QSAR modeling since it can improve model performance and transparency, as well as reduce the computational cost of model fitting and predictions. Which variable selection methods that perform well in QSAR settings is largely unknown. To address this question we, in a total of 1728 benchmarking experiments, rigorously investigated how eight variable selection methods affect the predictive performance and transparency of random forest models fitted to seven QSAR datasets covering different endpoints, descriptors sets, types of response variables, and number of chemical compounds. The results show that univariate variable selection methods are suboptimal and that the number of variables in the benchmarked datasets can be reduced with about 60 % without significant loss in model performance when using multivariate adaptive regression splines MARS and forward selection.

  5. Benchmarking of neutron production of heavy-ion transport codes

    Energy Technology Data Exchange (ETDEWEB)

    Remec, I. [Oak Ridge National Laboratory, Oak Ridge, TN 37831-6172 (United States); Ronningen, R. M. [Michigan State Univ., National Superconductiong Cyclotron Laboratory, East Lansing, MI 48824-1321 (United States); Heilbronn, L. [Univ. of Tennessee, 1004 Estabrook Rd., Knoxville, TN 37996-2300 (United States)

    2011-07-01

    Document available in abstract form only, full text of document follows: Accurate prediction of radiation fields generated by heavy ion interactions is important in medical applications, space missions, and in design and operation of rare isotope research facilities. In recent years, several well-established computer codes in widespread use for particle and radiation transport calculations have been equipped with the capability to simulate heavy ion transport and interactions. To assess and validate these capabilities, we performed simulations of a series of benchmark-quality heavy ion experiments with the computer codes FLUKA, MARS15, MCNPX, and PHITS. We focus on the comparisons of secondary neutron production. Results are encouraging; however, further improvements in models and codes and additional benchmarking are required. (authors)

  6. Evaluation of cloud resolving model simulations of midlatitude cirrus with ARM and A-Train observations

    Science.gov (United States)

    Muehlbauer, A. D.; Ackerman, T. P.; Lawson, P.; Xie, S.; Zhang, Y.

    2015-12-01

    This paper evaluates cloud resolving model (CRM) and cloud system-resolving model (CSRM) simulations of a midlatitude cirrus case with comprehensive observations collected under the auspices of the Atmospheric Radiation Measurements (ARM) program and with spaceborne observations from the National Aeronautics and Space Administration (NASA) A-train satellites. Vertical profiles of temperature, relative humidity and wind speeds are reasonably well simulated by the CSRM and CRM but there are remaining biases in the temperature, wind speeds and relative humidity, which can be mitigated through nudging the model simulations toward the observed radiosonde profiles. Simulated vertical velocities are underestimated in all simulations except in the CRM simulations with grid spacings of 500m or finer, which suggests that turbulent vertical air motions in cirrus clouds need to be parameterized in GCMs and in CSRM simulations with horizontal grid spacings on the order of 1km. The simulated ice water content and ice number concentrations agree with the observations in the CSRM but are underestimated in the CRM simulations. The underestimation of ice number concentrations is consistent with the overestimation of radar reflectivity in the CRM simulations and suggests that the model produces too many large ice particles especially toward cloud base. Simulated cloud profiles are rather insensitive to perturbations in the initial conditions or the dimensionality of the model domain but the treatment of the forcing data has a considerable effect on the outcome of the model simulations. Despite considerable progress in observations and microphysical parameterizations, simulating the microphysical, macrophysical and radiative properties of cirrus remains challenging. Comparing model simulations with observations from multiple instruments and observational platforms is important for revealing model deficiencies and for providing rigorous benchmarks. However, there still is considerable

  7. Modelling phosphorus (P), sulfur (S) and iron (Fe) interactions for dynamic simulations of anaerobic digestion processes

    DEFF Research Database (Denmark)

    Flores Alsina, Xavier; Solon, Kimberly; Kazadi Mbamba, Christian

    2016-01-01

    This paper proposes a series of extensions to functionally upgrade the IWA Anaerobic Digestion Model No. 1 (ADM1) to allow for plant-wide phosphorus (P) simulation. The close interplay between the P, sulfur (S) and iron (Fe) cycles requires a substantial (and unavoidable) increase in model...... complexity due to the involved three-phase physico-chemical and biological transformations. The ADM1 version, implemented in the plant-wide context provided by the Benchmark Simulation Model No. 2 (BSM2), is used as the basic platform (A0). Three different model extensions (A1, A2, A3) are implemented......, simulated and evaluated. The first extension (A1) considers P transformations by accounting for the kinetic decay of polyphosphates (XPP) and potential uptake of volatile fatty acids (VFA) to produce polyhydroxyalkanoates (XPHA) by phosphorus accumulating organisms (XPAO). Two variant extensions (A2,1/A2...

  8. Ab initio modeling of small proteins by iterative TASSER simulations

    Directory of Open Access Journals (Sweden)

    Zhang Yang

    2007-05-01

    Full Text Available Abstract Background Predicting 3-dimensional protein structures from amino-acid sequences is an important unsolved problem in computational structural biology. The problem becomes relatively easier if close homologous proteins have been solved, as high-resolution models can be built by aligning target sequences to the solved homologous structures. However, for sequences without similar folds in the Protein Data Bank (PDB library, the models have to be predicted from scratch. Progress in the ab initio structure modeling is slow. The aim of this study was to extend the TASSER (threading/assembly/refinement method for the ab initio modeling and examine systemically its ability to fold small single-domain proteins. Results We developed I-TASSER by iteratively implementing the TASSER method, which is used in the folding test of three benchmarks of small proteins. First, data on 16 small proteins (α-root mean square deviation (RMSD of 3.8Å, with 6 of them having a Cα-RMSD α-RMSD α-RMSD of the I-TASSER models was 3.9Å, whereas it was 5.9Å using TOUCHSTONE-II software. Finally, 20 non-homologous small proteins (α-RMSD of 3.9Å was obtained for the third benchmark, with seven cases having a Cα-RMSD Conclusion Our simulation results show that I-TASSER can consistently predict the correct folds and sometimes high-resolution models for small single-domain proteins. Compared with other ab initio modeling methods such as ROSETTA and TOUCHSTONE II, the average performance of I-TASSER is either much better or is similar within a lower computational time. These data, together with the significant performance of automated I-TASSER server (the Zhang-Server in the 'free modeling' section of the recent Critical Assessment of Structure Prediction (CASP7 experiment, demonstrate new progresses in automated ab initio model generation. The I-TASSER server is freely available for academic users http://zhang.bioinformatics.ku.edu/I-TASSER.

  9. VHDL simulation with access to transistor models

    Science.gov (United States)

    Gibson, J.

    1991-01-01

    Hardware description languages such as VHDL have evolved to aid in the design of systems with large numbers of elements and a wide range of electronic and logical abstractions. For high performance circuits, behavioral models may not be able to efficiently include enough detail to give designers confidence in a simulation's accuracy. One option is to provide a link between the VHDL environment and a transistor level simulation environment. The coupling of the Vantage Analysis Systems VHDL simulator and the NOVA simulator provides the combination of VHDL modeling and transistor modeling.

  10. Can a quantitative simulation of an Otto engine be accurately rendered by a simple Novikov model with heat leak?

    Science.gov (United States)

    Fischer, A.; Hoffmann, K.-H.

    2004-03-01

    In this case study a complex Otto engine simulation provides data including, but not limited to, effects from losses due to heat conduction, exhaust losses and frictional losses. This data is used as a benchmark to test whether the Novikov engine with heat leak, a simple endoreversible model, can reproduce the complex engine behavior quantitatively by an appropriate choice of model parameters. The reproduction obtained proves to be of high quality.

  11. MODELING AND SIMULATION OF SOLID FLUIDIZATION IN A RESIN COLUMN

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.

    2014-06-24

    The objective of the present work is to model the resin particles within the column during fluidization and sedimentation processes using computation fluid dynamics (CFD) approach. The calculated results will help interpret experimental results, and they will assist in providing guidance on specific details of testing design and establishing a basic understanding of particle’s hydraulic characteristics within the column. The model is benchmarked against the literature data and the test data (2003) conducted at Savannah River Site (SRS). The paper presents the benchmarking results and the modeling predictions of the SRS resin column using the improved literature correlations applicable for liquid-solid granular flow.

  12. A Lagrangian particle method for the simulation of linear and nonlinear elastic models of soft tissue

    Science.gov (United States)

    Hieber, Simone E.; Koumoutsakos, Petros

    2008-11-01

    We present a novel Lagrangian particle method for the simulation of linear and nonlinear elastic models of soft tissue. Linear solids are represented by the Lagrangian formulation of the stress-strain relationship that is extended to nonlinear solids by using the Lagrangian evolution of the deformation gradient described in a moving framework. The present method introduces a level set description, along with the particles, to capture the body deformations and to enforce the boundary conditions. Furthermore, the accuracy of the method in cases of large deformations is ensured by implementing a particle remeshing procedure. The method is validated in several benchmark problems, in two and three dimensions and the results compare well with the results of respective finite elements simulations. In simulations of large solid deformation under plane strain compression, the finite element solver exhibits spurious structures that are not present in the Lagrangian particle simulations. The particle simulations are compared with experimental results in an aspiration test of liver tissue.

  13. Modeling and Simulation of Low Voltage Arcs

    NARCIS (Netherlands)

    Ghezzi, L.; Balestrero, A.

    2010-01-01

    Modeling and Simulation of Low Voltage Arcs is an attempt to improve the physical understanding, mathematical modeling and numerical simulation of the electric arcs that are found during current interruptions in low voltage circuit breakers. An empirical description is gained by refined electrical m

  14. Handleiding benchmark VO

    NARCIS (Netherlands)

    Blank, j.l.t.

    2008-01-01

    OnderzoeksrapportenArchiefTechniek, Bestuur en Management> Over faculteit> Afdelingen> Innovation Systems> IPSE> Onderzoek> Publicaties> Onderzoeksrapporten> Handleiding benchmark VO Handleiding benchmark VO 25 november 2008 door IPSE Studies Door J.L.T. Blank. Handleiding voor het lezen van de i

  15. Benchmark af erhvervsuddannelserne

    DEFF Research Database (Denmark)

    Bogetoft, Peter; Wittrup, Jesper

    I dette arbejdspapir diskuterer vi, hvorledes de danske erhvervsskoler kan benchmarkes, og vi præsenterer resultaterne af en række beregningsmodeller. Det er begrebsmæssigt kompliceret at benchmarke erhvervsskolerne. Skolerne udbyder en lang række forskellige uddannelser. Det gør det vanskeligt...

  16. Benchmarking af kommunernes sagsbehandling

    DEFF Research Database (Denmark)

    Amilon, Anna

    Fra 2007 skal Ankestyrelsen gennemføre benchmarking af kommuernes sagsbehandlingskvalitet. Formålet med benchmarkingen er at udvikle praksisundersøgelsernes design med henblik på en bedre opfølgning og at forbedre kommunernes sagsbehandling. Dette arbejdspapir diskuterer metoder for benchmarking...

  17. Thermal Performance Benchmarking (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, G.

    2014-11-01

    This project will benchmark the thermal characteristics of automotive power electronics and electric motor thermal management systems. Recent vehicle systems will be benchmarked to establish baseline metrics, evaluate advantages and disadvantages of different thermal management systems, and identify areas of improvement to advance the state-of-the-art.

  18. Benchmark Energetic Data in a Model System for Grubbs II Metathesis Catalysis and Their Use for the Development, Assessment, and Validation of Electronic Structure Methods

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yan; Truhlar, Donald G.

    2009-01-31

    We present benchmark relative energetics in the catalytic cycle of a model system for Grubbs second-generation olefin metathesis catalysts. The benchmark data were determined by a composite approach based on CCSD(T) calculations, and they were used as a training set to develop a new spin-component-scaled MP2 method optimized for catalysis, which is called SCSC-MP2. The SCSC-MP2 method has improved performance for modeling Grubbs II olefin metathesis catalysts as compared to canonical MP2 or SCS-MP2. We also employed the benchmark data to test 17 WFT methods and 39 density functionals. Among the tested density functionals, M06 is the best performing functional. M06/TZQS gives an MUE of only 1.06 kcal/mol, and it is a much more affordable method than the SCSC-MP2 method or any other correlated WFT methods. The best performing meta-GGA is M06-L, and M06-L/DZQ gives an MUE of 1.77 kcal/mol. PBEh is the best performing hybrid GGA, with an MUE of 3.01 kcal/mol; however, it does not perform well for the larger, real Grubbs II catalyst. B3LYP and many other functionals containing the LYP correlation functional perform poorly, and B3LYP underestimates the stability of stationary points for the cis-pathway of the model system by a large margin. From the assessments, we recommend the M06, M06-L, and MPW1B95 functionals for modeling Grubbs II olefin metathesis catalysts. The local M06-L method is especially efficient for calculations on large systems.

  19. Shielding integral benchmark archive and database (SINBAD)

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, B.L.; Grove, R.E. [Radiation Safety Information Computational Center RSICC, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6171 (United States); Kodeli, I. [Josef Stefan Inst., Jamova 39, 1000 Ljubljana (Slovenia); Gulliford, J.; Sartori, E. [OECD NEA Data Bank, Bd des Iles, 92130 Issy-les-Moulineaux (France)

    2011-07-01

    The shielding integral benchmark archive and database (SINBAD) collection of experiments descriptions was initiated in the early 1990s. SINBAD is an international collaboration between the Organization for Economic Cooperation and Development's Nuclear Energy Agency Data Bank (OECD/NEADB) and the Radiation Safety Information Computational Center (RSICC) at Oak Ridge National Laboratory (ORNL). SINBAD was designed to compile experiments and corresponding computational models with the goal of preserving institutional knowledge and expertise that need to be handed down to future scientists. SINBAD can serve as a learning tool for university students and scientists who need to design experiments or gain expertise in modeling and simulation. The SINBAD database is currently divided into three categories - fission, fusion, and accelerator experiments. Many experiments are described and analyzed using deterministic or stochastic (Monte Carlo) radiation transport software. The nuclear cross sections also play an important role as they are necessary in performing computational analysis. (authors)

  20. 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...

  1. Benchmark of Atucha-2 PHWR RELAP5-3D control rod model by Monte Carlo MCNP5 core calculation

    Energy Technology Data Exchange (ETDEWEB)

    Pecchia, M.; D' Auria, F. [San Piero A Grado Nuclear Research Group GRNSPG, Univ. of Pisa, via Diotisalvi, 2, 56122 - Pisa (Italy); Mazzantini, O. [Nucleo-electrica Argentina Societad Anonima NA-SA, Buenos Aires (Argentina)

    2012-07-01

    Atucha-2 is a Siemens-designed PHWR reactor under construction in the Republic of Argentina. Its geometrical complexity and peculiarities require the adoption of advanced Monte Carlo codes for performing realistic neutronic simulations. Therefore core models of Atucha-2 PHWR were developed using MCNP5. In this work a methodology was set up to collect the flux in the hexagonal mesh by which the Atucha-2 core is represented. The scope of this activity is to evaluate the effect of obliquely inserted control rod on neutron flux in order to validate the RELAP5-3D{sup C}/NESTLE three dimensional neutron kinetic coupled thermal-hydraulic model, applied by GRNSPG/UNIPI for performing selected transients of Chapter 15 FSAR of Atucha-2. (authors)

  2. Simulation of subgrid orographic precipitation with an embedded 2-D cloud-resolving model

    Science.gov (United States)

    Jung, Joon-Hee; Arakawa, Akio

    2016-03-01

    By explicitly resolving cloud-scale processes with embedded two-dimensional (2-D) cloud-resolving models (CRMs), superparameterized global atmospheric models have successfully simulated various atmospheric events over a wide range of time scales. Up to now, however, such models have not included the effects of topography on the CRM grid scale. We have used both 3-D and 2-D CRMs to simulate the effects of topography with prescribed "large-scale" winds. The 3-D CRM is used as a benchmark. The results show that the mean precipitation can be simulated reasonably well by using a 2-D representation of topography as long as the statistics of the topography such as the mean and standard deviation are closely represented. It is also shown that the use of a set of two perpendicular 2-D grids can significantly reduce the error due to a 2-D representation of topography.

  3. Comparative evaluation of 1D and quasi-2D hydraulic models based on benchmark and real-world applications for uncertainty assessment in flood mapping

    Science.gov (United States)

    Dimitriadis, Panayiotis; Tegos, Aristoteles; Oikonomou, Athanasios; Pagana, Vassiliki; Koukouvinos, Antonios; Mamassis, Nikos; Koutsoyiannis, Demetris; Efstratiadis, Andreas

    2016-03-01

    One-dimensional and quasi-two-dimensional hydraulic freeware models (HEC-RAS, LISFLOOD-FP and FLO-2d) are widely used for flood inundation mapping. These models are tested on a benchmark test with a mixed rectangular-triangular channel cross section. Using a Monte-Carlo approach, we employ extended sensitivity analysis by simultaneously varying the input discharge, longitudinal and lateral gradients and roughness coefficients, as well as the grid cell size. Based on statistical analysis of three output variables of interest, i.e. water depths at the inflow and outflow locations and total flood volume, we investigate the uncertainty enclosed in different model configurations and flow conditions, without the influence of errors and other assumptions on topography, channel geometry and boundary conditions. Moreover, we estimate the uncertainty associated to each input variable and we compare it to the overall one. The outcomes of the benchmark analysis are further highlighted by applying the three models to real-world flood propagation problems, in the context of two challenging case studies in Greece.

  4. Modeling and Simulation of Matrix Converter

    DEFF Research Database (Denmark)

    Liu, Fu-rong; Klumpner, Christian; Blaabjerg, Frede

    2005-01-01

    This paper discusses the modeling and simulation of matrix converter. Two models of matrix converter are presented: one is based on indirect space vector modulation and the other is based on power balance equation. The basis of these two models is• given and the process on modeling is introduced...

  5. Warehouse Simulation Through Model Configuration

    NARCIS (Netherlands)

    Verriet, J.H.; Hamberg, R.; Caarls, J.; Wijngaarden, B. van

    2013-01-01

    The pre-build development of warehouse systems leads from a specific customer request to a specific customer quotation. This involves a process of configuring a warehouse system using a sequence of steps that contain increasingly more details. Simulation is a helpful tool in analyzing warehouse desi

  6. CAUSA - An Environment For Modeling And Simulation

    Science.gov (United States)

    Dilger, Werner; Moeller, Juergen

    1989-03-01

    CAUSA is an environment for modeling and simulation of dynamic systems on a quantitative level. The environment provides a conceptual framework including primitives like objects, processes and causal dependencies which allow the modeling of a broad class of complex systems. The facility of simulation allows the quantitative and qualitative inspection and empirical investigation of the behavior of the modeled system. CAUSA is implemented in Knowledge-Craft and runs on a Symbolics 3640.

  7. A benchmark for fault tolerant flight control evaluation

    Science.gov (United States)

    Smaili, H.; Breeman, J.; Lombaerts, T.; Stroosma, O.

    2013-12-01

    A large transport aircraft simulation benchmark (REconfigurable COntrol for Vehicle Emergency Return - RECOVER) has been developed within the GARTEUR (Group for Aeronautical Research and Technology in Europe) Flight Mechanics Action Group 16 (FM-AG(16)) on Fault Tolerant Control (2004 2008) for the integrated evaluation of fault detection and identification (FDI) and reconfigurable flight control strategies. The benchmark includes a suitable set of assessment criteria and failure cases, based on reconstructed accident scenarios, to assess the potential of new adaptive control strategies to improve aircraft survivability. The application of reconstruction and modeling techniques, based on accident flight data, has resulted in high-fidelity nonlinear aircraft and fault models to evaluate new Fault Tolerant Flight Control (FTFC) concepts and their real-time performance to accommodate in-flight failures.

  8. Simulation-based Manufacturing System Modeling

    Institute of Scientific and Technical Information of China (English)

    卫东; 金烨; 范秀敏; 严隽琪

    2003-01-01

    In recent years, computer simulation appears to be very advantageous technique for researching the resource-constrained manufacturing system. This paper presents an object-oriented simulation modeling method, which combines the merits of traditional methods such as IDEF0 and Petri Net. In this paper, a four-layer-one-angel hierarchical modeling framework based on OOP is defined. And the modeling description of these layers is expounded, such as: hybrid production control modeling and human resource dispatch modeling. To validate the modeling method, a case study of an auto-product line in a motor manufacturing company has been carried out.

  9. Quantum simulation of the t- J model

    Science.gov (United States)

    Yamaguchi, Fumiko; Yamamoto, Yoshihisa

    2002-12-01

    Computer simulation of a many-particle quantum system is bound to reach the inevitable limits of its ability as the system size increases. The primary reason for this is that the memory size used in a classical simulator grows polynomially whereas the Hilbert space of the quantum system does so exponentially. Replacing the classical simulator by a quantum simulator would be an effective method of surmounting this obstacle. The prevailing techniques for simulating quantum systems on a quantum computer have been developed for purposes of computing numerical algorithms designed to obtain approximate physical quantities of interest. The method suggested here requires no numerical algorithms; it is a direct isomorphic translation between a quantum simulator and the quantum system to be simulated. In the quantum simulator, physical parameters of the system, which are the fixed parameters of the simulated quantum system, are under the control of the experimenter. A method of simulating a model for high-temperature superconducting oxides, the t- J model, by optical control, as an example of such a quantum simulation, is presented.

  10. Advanced fluid modelling and PIC/MCC simulations of low-pressure ccrf discharges

    CERN Document Server

    Becker, Markus M; Sun, Anbang; Bonitz, Michael; Loffhagen, Detlef

    2016-01-01

    Comparative studies of capacitively coupled radio-frequency discharges in helium and argon at pressures between 10 and 80 Pa are presented applying two different fluid modelling approaches as well as two independently developed particle-in-cell/Monte Carlo collision (PIC/MCC) codes. The focus is on the analysis of the range of applicability of a recently proposed fluid model including an improved drift-diffusion approximation for the electron component as well as its comparison with fluid modelling results using the classical drift-diffusion approximation and benchmark results obtained by PIC/MCC simulations. Main features of this time- and space-dependent fluid model are given. It is found that the novel approach shows generally quite good agreement with the macroscopic properties derived by the kinetic simulations and is largely able to characterize qualitatively and quantitatively the discharge behaviour even at conditions when the classical fluid modelling approach fails. Furthermore, the excellent agreem...

  11. Multiscale Model Approach for Magnetization Dynamics Simulations

    CERN Document Server

    De Lucia, Andrea; Tretiakov, Oleg A; Kläui, Mathias

    2016-01-01

    Simulations of magnetization dynamics in a multiscale environment enable rapid evaluation of the Landau-Lifshitz-Gilbert equation in a mesoscopic sample with nanoscopic accuracy in areas where such accuracy is required. We have developed a multiscale magnetization dynamics simulation approach that can be applied to large systems with spin structures that vary locally on small length scales. To implement this, the conventional micromagnetic simulation framework has been expanded to include a multiscale solving routine. The software selectively simulates different regions of a ferromagnetic sample according to the spin structures located within in order to employ a suitable discretization and use either a micromagnetic or an atomistic model. To demonstrate the validity of the multiscale approach, we simulate the spin wave transmission across the regions simulated with the two different models and different discretizations. We find that the interface between the regions is fully transparent for spin waves with f...

  12. Benchmarking expert system tools

    Science.gov (United States)

    Riley, Gary

    1988-01-01

    As part of its evaluation of new technologies, the Artificial Intelligence Section of the Mission Planning and Analysis Div. at NASA-Johnson has made timing tests of several expert system building tools. Among the production systems tested were Automated Reasoning Tool, several versions of OPS5, and CLIPS (C Language Integrated Production System), an expert system builder developed by the AI section. Also included in the test were a Zetalisp version of the benchmark along with four versions of the benchmark written in Knowledge Engineering Environment, an object oriented, frame based expert system tool. The benchmarks used for testing are studied.

  13. Toxicological Benchmarks for Wildlife

    Energy Technology Data Exchange (ETDEWEB)

    Sample, B.E. Opresko, D.M. Suter, G.W.

    1993-01-01

    Ecological risks of environmental contaminants are evaluated by using a two-tiered process. In the first tier, a screening assessment is performed where concentrations of contaminants in the environment are compared to no observed adverse effects level (NOAEL)-based toxicological benchmarks. These benchmarks represent concentrations of chemicals (i.e., concentrations presumed to be nonhazardous to the biota) in environmental media (water, sediment, soil, food, etc.). While exceedance of these benchmarks does not indicate any particular level or type of risk, concentrations below the benchmarks should not result in significant effects. In practice, when contaminant concentrations in food or water resources are less than these toxicological benchmarks, the contaminants may be excluded from further consideration. However, if the concentration of a contaminant exceeds a benchmark, that contaminant should be retained as a contaminant of potential concern (COPC) and investigated further. The second tier in ecological risk assessment, the baseline ecological risk assessment, may use toxicological benchmarks as part of a weight-of-evidence approach (Suter 1993). Under this approach, based toxicological benchmarks are one of several lines of evidence used to support or refute the presence of ecological effects. Other sources of evidence include media toxicity tests, surveys of biota (abundance and diversity), measures of contaminant body burdens, and biomarkers. This report presents NOAEL- and lowest observed adverse effects level (LOAEL)-based toxicological benchmarks for assessment of effects of 85 chemicals on 9 representative mammalian wildlife species (short-tailed shrew, little brown bat, meadow vole, white-footed mouse, cottontail rabbit, mink, red fox, and whitetail deer) or 11 avian wildlife species (American robin, rough-winged swallow, American woodcock, wild turkey, belted kingfisher, great blue heron, barred owl, barn owl, Cooper's hawk, and red

  14. Systematic modelling and simulation of refrigeration systems

    DEFF Research Database (Denmark)

    Rasmussen, Bjarne D.; Jakobsen, Arne

    1998-01-01

    The task of developing a simulation model of a refrigeration system can be very difficult and time consuming. In order for this process to be effective, a systematic method for developing the system model is required. This method should aim at guiding the developer to clarify the purpose of the s......The task of developing a simulation model of a refrigeration system can be very difficult and time consuming. In order for this process to be effective, a systematic method for developing the system model is required. This method should aim at guiding the developer to clarify the purpose...... of the simulation, to select appropriate component models and to set up the equations in a well-arranged way. In this paper the outline of such a method is proposed and examples showing the use of this method for simulation of refrigeration systems are given....

  15. 超高层建筑结构 benchmark 模型及其地震反应分析%A Benchmark Model of Mega-tall Buildings and Analysis of its Seismic Responses

    Institute of Scientific and Technical Information of China (English)

    吕西林; 姜淳; 蒋欢军

    2015-01-01

    参照上海中心,根据设定的性能目标设计了一个超高层建筑结构的 benchmark 模型用于超高层建筑结构抗震研究。该结构总高度为606.1 m,抗震设防烈度为7度,场地类别为 IV 类,设计分组为第一组。该结构采用巨型框架-核心筒-伸臂桁架钢-混凝土混合结构体系,8道环带桁架将结构分为9个区,环带桁架与型钢混凝土巨柱共同构成了巨型框架结构体系,并通过6道伸臂桁架与核心筒相连,共同承受水平荷载。利用 PERFORM-3D 软件建立了结构的非线性数值计算模型,对结构进行了弹塑性地震反应分析,验证了结构的抗震性能。计算结果表明,满足现行设计规范的该超高层结构在大震作用下具有较大的安全余量。%This paper proposes a benchmark model of mega-tall buildings for investigating the seismic performance.The structure is designed based on the prototype of Shanghai Tower with the specific seismic performance objective.The total height of the structure is 606.1 m,with the seismic fortification of intensity of 7.The soil type is IV,and the seismic design class is the 1st class.The mega frame-core tube with outriggers steel-concrete composite structure system is adopped.The structure is divided into 9 zones by 8 belted trusses which form the mega frame system together with SRC mega-columns.The mega frame is connected to the core tube with 6 outrigger trusses,resisting the lateral load together.The elasto-plastic analysis of the model is conducted to validate the seismic performance by using PERFORM-3D software.The result shows that the structure which meets the requirements of the current design code has a considerable safety margin under severe earthquakes.

  16. 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.

  17. HVDC System Characteristics and Simulation Models

    Energy Technology Data Exchange (ETDEWEB)

    Moon, S.I.; Han, B.M.; Jang, G.S. [Electric Enginnering and Science Research Institute, Seoul (Korea)

    2001-07-01

    This report deals with the AC-DC power system simulation method by PSS/E and EUROSTAG for the development of a strategy for the reliable operation of the Cheju-Haenam interconnected system. The simulation using both programs is performed to analyze HVDC simulation models. In addition, the control characteristics of the Cheju-Haenam HVDC system as well as Cheju AC system characteristics are described in this work. (author). 104 figs., 8 tabs.

  18. Simple Benchmark Specifications for Space Radiation Protection

    Science.gov (United States)

    Singleterry, Robert C. Jr.; Aghara, Sukesh K.

    2013-01-01

    This report defines space radiation benchmark specifications. This specification starts with simple, monoenergetic, mono-directional particles on slabs and progresses to human models in spacecraft. This report specifies the models and sources needed to what the team performing the benchmark needs to produce in a report. Also included are brief descriptions of how OLTARIS, the NASA Langley website for space radiation analysis, performs its analysis.

  19. Modeling and simulation for RF system design

    CERN Document Server

    Frevert, Ronny; Jancke, Roland; Knöchel, Uwe; Schwarz, Peter; Kakerow, Ralf; Darianian, Mohsen

    2005-01-01

    Focusing on RF specific modeling and simulation methods, and system and circuit level descriptions, this work contains application-oriented training material. Accompanied by a CD- ROM, it combines the presentation of a mixed-signal design flow, an introduction into VHDL-AMS and Verilog-A, and the application of commercially available simulators.

  20. 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

  1. A sand wave simulation model

    NARCIS (Netherlands)

    Nemeth, A.A.; Hulscher, S.J.M.H.; Damme, van R.M.J.

    2003-01-01

    Sand waves form a prominent regular pattern in the offshore seabeds of sandy shallow seas. A two dimensional vertical (2DV) flow and morphological numerical model describing the behaviour of these sand waves has been developed. The model contains the 2DV shallow water equations, with a free water su

  2. GeodeticBenchmark_GEOMON

    Data.gov (United States)

    Vermont Center for Geographic Information — The GeodeticBenchmark_GEOMON data layer consists of geodetic control monuments (points) that have a known position or spatial reference. The locations of these...

  3. Diagnostic Algorithm Benchmarking

    Science.gov (United States)

    Poll, Scott

    2011-01-01

    A poster for the NASA Aviation Safety Program Annual Technical Meeting. It describes empirical benchmarking on diagnostic algorithms using data from the ADAPT Electrical Power System testbed and a diagnostic software framework.

  4. Financial Integrity Benchmarks

    Data.gov (United States)

    City of Jackson, Mississippi — This data compiles standard financial integrity benchmarks that allow the City to measure its financial standing. It measure the City's debt ratio and bond ratings....

  5. 基于LQG性能基准的预测控制经济性能评估算法%Economic performance assessment of model predictive control (MPC) based on LQG benchmarking

    Institute of Scientific and Technical Information of China (English)

    赵超; 张登峰; 许巧玲; 李学来

    2012-01-01

    With the goals of optimal performance, energy conservation and cost effectiveness of process operations in industry, economic performance assessment of advanced process control have received great attention in both academia and industry. Controller performance monitoring and assessment are necessary to assure effectiveness of model predictive control systems and consequently safe and profitable plant operation. An approach to economic performance assessment of model predictive control system is presented. The method builds on steady-state economic optimization techniques and uses the linear quadratic gaussian (LQG) benchmark other than conventional minimum variance control (MVC) to estimate the potential of reduction in variance. The LQG control is a more practical performance benchmark compared to MVC for performance assessment since it considers input variance and output variance, and it thus provides a desired basis for determining the theoretical maximum economic benefit potential arising from variability reduction. Combining the LQG benchmark directly with benefit potential of MPC control system, both the economic benefits and the optimal operation condition can be obtained by solving the economic optimization problem. The proposed algorithm is illustrated by a simulated example of Shell standard problem.%针对已有经济性能评估算法大多采用最小方差控制(Minimum Variance Control,MVC)性能基准,存在对预测控制系统(Model Predictive Control,MPC)性能评估结果可靠性不高的问题,提出了基于线性二次高斯控制(Linear Quadratic Gaussian,LQG)性能基准的经济性能评估算法.通过数值计算方法确定LQG性能基准曲线,避免了复杂交互矩阵的计算.算法以基于模型的稳态经济优化技术为基础,将LQG基准和预测控制系统的经济性能估计相结合,并通过建立一系列稳态优化问题来描述控制系统在不同控制策略下的经济性能.与已有评估算法相比,本

  6. CERN Proton Synchrotron booster space charge simulations with a realistic model for alignment and field errors*

    Science.gov (United States)

    Forte, V.; Benedetto, E.; McAteer, M.

    2016-12-01

    The CERN Proton Synchrotron booster (PSB) is one of the machines of the LHC injector chain which will be upgraded within the LHC Injectors Upgrade (LIU) project. The injection energy of the PSB will be increased to 160 MeV in order to mitigate direct space charge effects, considered to be the main performance limitation, aiming to double the brightness for the LHC beams. In order to better predict the gain to be expected, space charge simulations are being carried out. As a first step, benchmarking between simulations and measurements is needed. Efforts to establish a realistic modeling of field and alignment errors aim at extending the basic model of the machine toward a more realistic one. Simulations of beam dynamics with strong space charge and realistic errors are presented and analyzed in this paper.

  7. Challenges in SysML Model Simulation

    Directory of Open Access Journals (Sweden)

    Mara Nikolaidou

    2016-07-01

    Full Text Available Systems Modeling Language (SysML is a standard proposed by the OMG for systems-of-systems (SoS modeling and engineering. To this end, it provides the means to depict SoS components and their behavior in a hierarchical, multi-layer fashion, facilitating alternative engineering activities, such as system design. To explore the performance of SysML, simulation is one of the preferred methods. There are many efforts targeting simulation code generation from SysML models. Numerous simulation methodologies and tools are employed, while different SysML diagrams are utilized. Nevertheless, this process is not standardized, although most of current approaches tend to follow the same steps, even if they employ different tools. The scope of this paper is to provide a comprehensive understanding of the similarities and differences of existing approaches and identify current challenges in fully automating SysML models simulation process.

  8. Modelling Reactive and Proactive Behaviour in Simulation

    CERN Document Server

    Majid, Mazlina Abdul; Aickelin, Uwe

    2010-01-01

    This research investigated the simulation model behaviour of a traditional and combined discrete event as well as agent based simulation models when modelling human reactive and proactive behaviour in human centric complex systems. A departmental store was chosen as human centric complex case study where the operation system of a fitting room in WomensWear department was investigated. We have looked at ways to determine the efficiency of new management policies for the fitting room operation through simulating the reactive and proactive behaviour of staff towards customers. Once development of the simulation models and their verification had been done, we carried out a validation experiment in the form of a sensitivity analysis. Subsequently, we executed a statistical analysis where the mixed reactive and proactive behaviour experimental results were compared with some reactive experimental results from previously published works. Generally, this case study discovered that simple proactive individual behaviou...

  9. Modelling phosphorus (P), sulphur (S) and iron (Fe) interactions during the simulation of anaerobic digestion processes

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Solon, Kimberly; Kazadi-Mbamba, Christian;

    2015-01-01

    ) and their potential effect on total biogas production (CO2, CH4, H2 and H2S). The ADM1 version, implemented in the plant-wide context provided by the Benchmark Simulation Model No. 2 (BSM2), is used as the basic platform (A0). Four (A1 – A4) different model extensions are implemented, simulated and evaluated....... The first approach (A1) considers P transformations by accounting for the kinetic decay of polyphosphates (XPP) and potential uptake of Volatile Fatty Acids (VFA) to produce Polyhydroxyalkanoates (XPHA) by Phosphorus Accumulating Organisms (XPAO). The second model formulation (A2) describes biological...... production of sulfide (SH2S) by means of Sulfate-Reducing Bacteria (XSRB). This approach also considers potential SH2S inhibition effect on biomass and mass transfer phenomena (aqueous-gas). The third evaluated model (A3) considers chemical iron (III) (SFe+3) reduction to iron (II) (SFe+2) using hydrogen (SH...

  10. Benchmarking in Foodservice Operations.

    Science.gov (United States)

    2007-11-02

    51. Lingle JH, Schiemann WA. From balanced scorecard to strategic gauges: Is measurement worth it? Mgt Rev. 1996; 85(3):56-61. 52. Struebing L...studies lasted from nine to twelve months, and could extend beyond that time for numerous reasons (49). Benchmarking was not industrial tourism , a...not simply data comparison, a fad, a means for reducing resources, a quick-fix program, or industrial tourism . Benchmarking was a complete process

  11. How Activists Use Benchmarks

    DEFF Research Database (Denmark)

    Seabrooke, Leonard; Wigan, Duncan

    2015-01-01

    Non-governmental organisations use benchmarks as a form of symbolic violence to place political pressure on firms, states, and international organisations. The development of benchmarks requires three elements: (1) salience, that the community of concern is aware of the issue and views it as impo...... interests and challenge established politico-economic norms. Differentiating these cycles provides insights into how activists work through organisations and with expert networks, as well as how campaigns on complex economic issues can be mounted and sustained....

  12. On Big Data Benchmarking

    OpenAIRE

    Han, Rui; Lu, Xiaoyi

    2014-01-01

    Big data systems address the challenges of capturing, storing, managing, analyzing, and visualizing big data. Within this context, developing benchmarks to evaluate and compare big data systems has become an active topic for both research and industry communities. To date, most of the state-of-the-art big data benchmarks are designed for specific types of systems. Based on our experience, however, we argue that considering the complexity, diversity, and rapid evolution of big data systems, fo...

  13. RISKIND verification and benchmark comparisons

    Energy Technology Data Exchange (ETDEWEB)

    Biwer, B.M.; Arnish, J.J.; Chen, S.Y.; Kamboj, S.

    1997-08-01

    This report presents verification calculations and benchmark comparisons for RISKIND, a computer code designed to estimate potential radiological consequences and health risks to individuals and the population from exposures associated with the transportation of spent nuclear fuel and other radioactive materials. Spreadsheet calculations were performed to verify the proper operation of the major options and calculational steps in RISKIND. The program is unique in that it combines a variety of well-established models into a comprehensive treatment for assessing risks from the transportation of radioactive materials. Benchmark comparisons with other validated codes that incorporate similar models were also performed. For instance, the external gamma and neutron dose rate curves for a shipping package estimated by RISKIND were compared with those estimated by using the RADTRAN 4 code and NUREG-0170 methodology. Atmospheric dispersion of released material and dose estimates from the GENII and CAP88-PC codes. Verification results have shown the program to be performing its intended function correctly. The benchmark results indicate that the predictions made by RISKIND are within acceptable limits when compared with predictions from similar existing models.

  14. Collisionless Electrostatic Shock Modeling and Simulation

    Science.gov (United States)

    2016-10-21

    Briefing Charts 3. DATES COVERED (From - To) 30 September 2016 – 21 October 2016 4. TITLE AND SUBTITLE Collisionless Electrostatic Shock Modeling and...release: distribution unlimited. PA#16490 Air Force Research Laboratory Collisionless Electrostatic Shock Modeling and Simulation Daniel W. Crews In-Space...unlimited. PA#16490 Overview • Motivation and Background • What is a Collisionless Shock Wave? • Features of the Collisionless Shock • The Shock Simulation

  15. Application of Chebyshev Polynomial to simulated modeling

    Institute of Scientific and Technical Information of China (English)

    CHI Hai-hong; LI Dian-pu

    2006-01-01

    Chebyshev polynomial is widely used in many fields, and used usually as function approximation in numerical calculation. In this paper, Chebyshev polynomial expression of the propeller properties across four quadrants is given at first, then the expression of Chebyshev polynomial is transformed to ordinary polynomial for the need of simulation of propeller dynamics. On the basis of it,the dynamical models of propeller across four quadrants are given. The simulation results show the efficiency of mathematical model.

  16. Traffic Modeling in WCDMA System Level Simulations

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Traffic modeling is a crucial element in WCDMA system level simulations. A clear understanding of the nature of traffic in the WCDMA system and subsequent selection of an appropriate random traffic model are critical to the success of the modeling enterprise. The resultant performances will evidently be of a function that our design has been well adapted to the traffic, channel and user mobility models, and these models are also accurate. In this article, our attention will be focused on modeling voice and WWW data traffic with the SBBP model and Victor model respectively.

  17. Modeling of magnetic particle suspensions for simulations

    CERN Document Server

    Satoh, Akira

    2017-01-01

    The main objective of the book is to highlight the modeling of magnetic particles with different shapes and magnetic properties, to provide graduate students and young researchers information on the theoretical aspects and actual techniques for the treatment of magnetic particles in particle-based simulations. In simulation, we focus on the Monte Carlo, molecular dynamics, Brownian dynamics, lattice Boltzmann and stochastic rotation dynamics (multi-particle collision dynamics) methods. The latter two simulation methods can simulate both the particle motion and the ambient flow field simultaneously. In general, specialized knowledge can only be obtained in an effective manner under the supervision of an expert. The present book is written to play such a role for readers who wish to develop the skill of modeling magnetic particles and develop a computer simulation program using their own ability. This book is therefore a self-learning book for graduate students and young researchers. Armed with this knowledge,...

  18. Modeling and simulation of multiport RF switch

    Energy Technology Data Exchange (ETDEWEB)

    Vijay, J [Student, Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchirappalli-620015 (India); Saha, Ivan [Scientist, Indian Space Research Organisation (ISRO) (India); Uma, G [Lecturer, Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchirappalli-620015 (India); Umapathy, M [Assistant Professor, Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchirappalli-620015 (India)

    2006-04-01

    This paper describes the modeling and simulation of 'Multi Port RF Switch' where the latching mechanism is realized with two hot arm electro thermal actuators and the switching action is realized with electrostatic actuators. It can act as single pole single thrown as well as single pole multi thrown switch. The proposed structure is modeled analytically and required parameters are simulated using MATLAB. The analytical simulation results are validated using Finite Element Analysis of the same in the COVENTORWARE software.

  19. Modeling and simulation of discrete event systems

    CERN Document Server

    Choi, Byoung Kyu

    2013-01-01

    Computer modeling and simulation (M&S) allows engineers to study and analyze complex systems. Discrete-event system (DES)-M&S is used in modern management, industrial engineering, computer science, and the military. As computer speeds and memory capacity increase, so DES-M&S tools become more powerful and more widely used in solving real-life problems. Based on over 20 years of evolution within a classroom environment, as well as on decades-long experience in developing simulation-based solutions for high-tech industries, Modeling and Simulation of Discrete-Event Systems is the only book on

  20. Assessment of evaluated (n,d) energy-angle elastic scattering distributions using MCNP simulations of critical measurements and simplified calculation benchmarks

    Energy Technology Data Exchange (ETDEWEB)

    Kozier, K.S. [Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario (Canada)

    2008-07-01

    Different evaluated (n,d) energy-angle elastic scattering distributions produce k-effective differences in MCNP5 simulations of critical experiments involving heavy water (D{sub 2}O) of sufficient magnitude to suggest a need for new (n,d) scattering measurements and/or distributions derived from modern theoretical nuclear models, especially at neutron energies below a few MeV. The present work focuses on the small reactivity change of < 1 mk that is observed in the MCNP5 D{sub 2}O coolant-void-reactivity calculation bias for simulations of two pairs of critical experiments performed in the ZED-2 reactor at the Chalk River Laboratories when different nuclear data libraries are used for deuterium. The deuterium data libraries tested include Endf/B-VII.0, Endf/B-VI.4, JENDL-3.3 and a new evaluation, labelled Bonn-B, which is based on recent theoretical nuclear-model calculations. Comparison calculations were also performed for a simplified, two-region, spherical model having an inner, 250-cm radius, homogeneous sphere of UO{sub 2}, without and with deuterium, and an outer 20-cm-thick deuterium reflector. A notable observation from this work is the reduction of about 0.4 mk in the MCNP5 ZED-2 CVR calculation bias that is obtained when the O-in-UO{sub 2} thermal scattering data comes from Endf-B-VII.0. (author)

  1. Benchmarking File System Benchmarking: It *IS* Rocket Science

    OpenAIRE

    Seltzer, Margo I.; Tarasov, Vasily; Bhanage, Saumitra; Zadok, Erez

    2011-01-01

    The quality of file system benchmarking has not improved in over a decade of intense research spanning hundreds of publications. Researchers repeatedly use a wide range of poorly designed benchmarks, and in most cases, develop their own ad-hoc benchmarks. Our community lacks a definition of what we want to benchmark in a file system. We propose several dimensions of file system benchmarking and review the wide range of tools and techniques in widespread use. We experimentally show that even t...

  2. Application of experimental design techniques to structural simulation meta-model building using neural network

    Institute of Scientific and Technical Information of China (English)

    费庆国; 张令弥

    2004-01-01

    Neural networks are being used to construct meta-models in numerical simulation of structures. In addition to network structures and training algorithms, training samples also greatly affect the accuracy of neural network models. In this paper, some existing main sampling techniques are evaluated, including techniques based on experimental design theory,random selection, and rotating sampling. First, advantages and disadvantages of each technique are reviewed. Then, seven techniques are used to generate samples for training radial neural networks models for two benchmarks: an antenna model and an aircraft model. Results show that the uniform design, in which the number of samples and mean square error network models are considered, is the best sampling technique for neural network based meta-model building.

  3. Microfluidic very large scale integration (VLSI) modeling, simulation, testing, compilation and physical synthesis

    CERN Document Server

    Pop, Paul; Madsen, Jan

    2016-01-01

    This book presents the state-of-the-art techniques for the modeling, simulation, testing, compilation and physical synthesis of mVLSI biochips. The authors describe a top-down modeling and synthesis methodology for the mVLSI biochips, inspired by microelectronics VLSI methodologies. They introduce a modeling framework for the components and the biochip architecture, and a high-level microfluidic protocol language. Coverage includes a topology graph-based model for the biochip architecture, and a sequencing graph to model for biochemical application, showing how the application model can be obtained from the protocol language. The techniques described facilitate programmability and automation, enabling developers in the emerging, large biochip market. · Presents the current models used for the research on compilation and synthesis techniques of mVLSI biochips in a tutorial fashion; · Includes a set of "benchmarks", that are presented in great detail and includes the source code of several of the techniques p...

  4. The KMAT: Benchmarking Knowledge Management.

    Science.gov (United States)

    de Jager, Martha

    Provides an overview of knowledge management and benchmarking, including the benefits and methods of benchmarking (e.g., competitive, cooperative, collaborative, and internal benchmarking). Arthur Andersen's KMAT (Knowledge Management Assessment Tool) is described. The KMAT is a collaborative benchmarking tool, designed to help organizations make…

  5. Modeling and Simulation of Hydraulic Engine Mounts

    Institute of Scientific and Technical Information of China (English)

    DUAN Shanzhong; Marshall McNea

    2012-01-01

    Hydraulic engine mounts are widely used in automotive powertrains for vibration isolation.A lumped mechanical parameter model is a traditional approach to model and simulate such mounts.This paper presents a dynamical model of a passive hydraulic engine mount with a double-chamber,an inertia track,a decoupler,and a plunger.The model is developed based on analogy between electrical systems and mechanical-hydraulic systems.The model is established to capture both low and high frequency dynatmic behaviors of the hydraulic mount.The model will be further used to find the approximate pulse responses of the mounts in terms of the force transmission and top chamber pressure.The close form solution from the simplifiod linear model may provide some insight into the highly nonlinear behavior of the mounts.Based on the model,computer simulation has been carried out to study dynamic performance of the hydraulic mount.

  6. 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....

  7. Modelling and simulating fire tube boiler performance

    DEFF Research Database (Denmark)

    Sørensen, Kim; Karstensen, Claus; Condra, Thomas Joseph;

    2003-01-01

    A model for a ue gas boiler covering the ue 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 dened 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 MatLab/Simulink has...... been applied for carrying out the simulations. To be able to verify the simulated results an experiments has been carried out on a full scale boiler plant....

  8. SOFT MODELLING AND SIMULATION IN STRATEGY

    Directory of Open Access Journals (Sweden)

    Luciano Rossoni

    2006-06-01

    Full Text Available A certain resistance on the part of the responsible controllers for the strategy exists, in using techniques and tools of modeling and simulation. Many find them excessively complicated, already others see them as rigid and mathematical for excessively for the use of strategies in uncertain and turbulent environments. However, some interpretative boarding that take care of, in part exist, the necessities of these borrowers of decision. The objective of this work is to demonstrate of a clear and simple form, some of the most powerful boarding, methodologies and interpretative tools (soft of modeling and simulation in the business-oriented area of strategy. We will define initially, what they are on models, simulation and some aspects to the modeling and simulation in the strategy area. Later we will see some boarding of modeling soft, that they see the modeling process much more of that simply a mechanical process, therefore, as seen for Simon, the human beings rationally are limited and its decisions are influenced by a series of questions of subjective character, related to the way where it is inserted. Keywords: strategy, modeling and simulation, soft systems methodology, cognitive map, systems dynamics.

  9. Remarks on a benchmark nonlinear constrained optimization problem

    Institute of Scientific and Technical Information of China (English)

    Luo Yazhong; Lei Yongjun; Tang Guojin

    2006-01-01

    Remarks on a benchmark nonlinear constrained optimization problem are made. Due to a citation error, two absolutely different results for the benchmark problem are obtained by independent researchers. Parallel simulated annealing using simplex method is employed in our study to solve the benchmark nonlinear constrained problem with mistaken formula and the best-known solution is obtained, whose optimality is testified by the Kuhn-Tucker conditions.

  10. Design and Benchmarking of a Network-In-the-Loop Simulation for Use in a Hardware-In-the-Loop System

    Science.gov (United States)

    Aretskin-Hariton, Eliot D.; Thomas, George Lindsey; Culley, Dennis E.; Kratz, Jonathan L.

    2017-01-01

    Distributed engine control (DEC) systems alter aircraft engine design constraints be- cause of fundamental differences in the input and output communication between DEC and centralized control architectures. The change in the way communication is implemented may create new optimum engine-aircraft configurations. This paper continues the exploration of digital network communication by demonstrating a Network-In-the-Loop simulation at the NASA Glenn Research Center. This simulation incorporates a real-time network protocol, the Engine Area Distributed Interconnect Network Lite (EADIN Lite), with the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k) software. The objective of this study is to assess digital control network impact to the control system. Performance is evaluated relative to a truth model for large transient maneuvers and a typical flight profile for commercial aircraft. Results show that a decrease in network bandwidth from 250 Kbps (sampling all sensors every time step) to 40 Kbps, resulted in very small differences in control system performance.

  11. 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......, focusing on universality of the ac response in the extreme disorder limit. Finally, some important unsolved problems relating to hopping models for ac conduction are listed....

  12. Benchmarking Danish Vocational Education and Training Programmes

    DEFF Research Database (Denmark)

    Bogetoft, Peter; Wittrup, Jesper

    This study paper discusses methods whereby Danish vocational education and training colleges can be benchmarked, and presents results from a number of models. It is conceptually complicated to benchmark vocational colleges, as the various colleges in Denmark offer a wide range of course programmes...... attempt to summarise the various effects that the colleges have in two relevant figures, namely retention rates of students and employment rates among students who have completed training programmes....

  13. Microgrid Modeling and Simulation Study

    Science.gov (United States)

    2016-09-01

    that will enable the US Army and Department of Defense (DOD) to align their M&S focus, develop a balanced microgrid M&S portfolio , and prioritize...and power interfaces should be standardized in a vendor agnostic manner. • A performance evaluation of hybrids or microgrids is a complex process...recommendation on an appropriate mix of microgrid technologies. This type of modeling is used to evaluate system performance over long time durations (typically

  14. Modeling and simulating of unloading welding transformer

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The simulation model of an unloading welding transformer was established on the basis of MATLAB software, and the modeling principle was described in detail in the paper. The model was made up of three sub-models, i.e. the linear inductor sub-model, the non-linear inductor sub-model and series connection sub-model controlled by current, and these sub-models were jointed together by means of segmented linearization. The simulating results showed that, in the conditions of the high convert frequency and the large cross section of the magnet core of a welding transformer, the non-linear inductor sub-model can be substituted by a linear inductor sub-model in the model; and the leakage reactance in the welding transformer is one of the main reasons of producing over-current and over-voltage in the inverter. The simulation results demonstrate that the over-voltage produced by leakage reactance is nearly two times of the input voltage supplied to the transformer, and the lasting time of over-voltage depends on time constant τ1. With reducing of τ1, the amplitude of the over-current will increase, and the lasting time becomes shorter. Contrarily, with increasing of τ1, the amplitude of the over-current will decrease, and the lasting time becomes longer. The model has played the important role for the development of the inverter resistance welding machine.

  15. Revolutions in energy through modeling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Tatro, M.; Woodard, J.

    1998-08-01

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

  16. Benchmarking in Mobarakeh Steel Company

    OpenAIRE

    Sasan Ghasemi; Mohammad Nazemi; Mehran Nejati

    2008-01-01

    Benchmarking is considered as one of the most effective ways of improving performance in companies. Although benchmarking in business organizations is a relatively new concept and practice, it has rapidly gained acceptance worldwide. This paper introduces the benchmarking project conducted in Esfahan's Mobarakeh Steel Company, as the first systematic benchmarking project conducted in Iran. It aims to share the process deployed for the benchmarking project in this company and illustrate how th...

  17. Benchmarking in Mobarakeh Steel Company

    Directory of Open Access Journals (Sweden)

    Sasan Ghasemi

    2008-05-01

    Full Text Available Benchmarking is considered as one of the most effective ways of improving performance incompanies. Although benchmarking in business organizations is a relatively new concept and practice, ithas rapidly gained acceptance worldwide. This paper introduces the benchmarking project conducted in Esfahan’s Mobarakeh Steel Company, as the first systematic benchmarking project conducted in Iran. It aimsto share the process deployed for the benchmarking project in this company and illustrate how the projectsystematic implementation led to succes.

  18. Modeling & Simulation Executive Agent Panel

    Science.gov (United States)

    2007-11-02

    Richard W. ; 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME AND ADDRESS Office of the Oceanographer of the Navy...acquisition, and training communities.” MSEA Role • Facilitator in the project startup phase • Catalyst during development • Certifier in the...ACOUSTIC MODELS Parabolic Equation 5.0 ASTRAL 5.0 ASPM 4.3 Gaussian Ray Bundle 1.0 High Freq Env Acoustic (HFEVA) 1.0 COLOSSUS II 1.0 Low Freq Bottom LOSS

  19. Simulering af dagslys i digitale modeller

    DEFF Research Database (Denmark)

    Villaume, René Domine; Ørstrup, Finn Rude

    2004-01-01

    Projektet undersøger via forskellige simuleringer af dagslys, kvaliteten af visualiseringer af komplekse lysforhold i digitale modeller i forbindelse med formidling af arkitektur via nettet. I en digital 3D model af Utzon Associates Paustians hus, simulers naturligt dagslysindfald med  forskellig...... Renderingsmetoder som: "shaded render" /  ”raytraceing” /  "Final Gather /  ”Global Illumination”...

  20. Simulation and modeling of turbulent flows

    CERN Document Server

    Gatski, Thomas B; Lumley, John L

    1996-01-01

    This book provides students and researchers in fluid engineering with an up-to-date overview of turbulent flow research in the areas of simulation and modeling. A key element of the book is the systematic, rational development of turbulence closure models and related aspects of modern turbulent flow theory and prediction. Starting with a review of the spectral dynamics of homogenous and inhomogeneous turbulent flows, succeeding chapters deal with numerical simulation techniques, renormalization group methods and turbulent closure modeling. Each chapter is authored by recognized leaders in their respective fields, and each provides a thorough and cohesive treatment of the subject.

  1. 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.

  2. PNNL Information Technology Benchmarking

    Energy Technology Data Exchange (ETDEWEB)

    DD Hostetler

    1999-09-08

    Benchmarking is a methodology for searching out industry best practices that lead to superior performance. It is exchanging information, not just with any organization, but with organizations known to be the best within PNNL, in industry, or in dissimilar industries with equivalent functions. It is used as a continuous improvement tool for business and technical processes, products, and services. Information technology--comprising all computer and electronic communication products and services--underpins the development and/or delivery of many PNNL products and services. This document describes the Pacific Northwest National Laboratory's (PNNL's) approach to information technology (IT) benchmarking. The purpose is to engage other organizations in the collaborative process of benchmarking in order to improve the value of IT services provided to customers. TM document's intended audience consists of other US Department of Energy (DOE) national laboratories and their IT staff. Although the individual participants must define the scope of collaborative benchmarking, an outline of IT service areas for possible benchmarking is described.

  3. On the accuracy of simulations of a 2D boundary layer with RANS models implemented in OpenFoam

    Science.gov (United States)

    Graves, Benjamin J.; Gomez, Sebastian; Poroseva, Svetlana V.

    2013-11-01

    The OpenFoam software is an attractive Computational Fluid Dynamics solver for evaluating new turbulence models due to the open-source nature, and the suite of existing standard model implementations. Before interpreting results obtained with a new model, a baseline for performance of the OpenFoam solver and existing models is required. In the current study we analyze the RANS models in the OpenFoam incompressible solver for two planar (two-dimensional mean flow) benchmark cases generated by the AIAA Turbulence Model Benchmarking Working Group (TMBWG): a zero-pressure-gradient flat plate and a bump-in-channel. The OpenFoam results are compared against both experimental data and simulation results obtained with the NASA CFD codes CFL3D and FUN3D. Sensitivity of simulation results to the grid resolution and model implementation are analyzed. Testing is conducted using the Spalart-Allmaras one-equation model, Wilcox's two-equation k-omega model, and the Launder-Reece-Rodi Reynolds-stress model. Simulations using both wall functions and wall-resolved (low Reynolds number) formulations are considered. The material is based upon work supported by NASA under award NNX12AJ61A.

  4. Power electronics system modeling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Jih-Sheng

    1994-12-31

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

  5. Simulation of Gravity Currents Using VOF Model

    Institute of Scientific and Technical Information of China (English)

    邹建锋; 黄钰期; 应新亚; 任安禄

    2002-01-01

    By the Volume of Fluid (VOF) multiphase flow model two-dimensional gravity currents with three phases including air are numerically simulated in this article. The necessity of consideration of turbulence effect for high Reynolds numbers is demonstrated quantitatively by LES (the Large Eddy Simulation) turbulence model. The gravity currents are simulated for h ≠ H as well as h = H, where h is the depth of the gravity current before the release and H is the depth of the intruded fluid. Uprising of swell occurs when a current flows horizontally into another lighter one for h ≠ H. The problems under what condition the uprising of swell occurs and how long it takes are considered in this article. All the simulated results are in reasonable agreement with the experimental results available.

  6. Numerical Simulation on Hydromechanical Coupling in Porous Media Adopting Three-Dimensional Pore-Scale Model

    Science.gov (United States)

    Liu, Jianjun; Song, Rui; Cui, Mengmeng

    2014-01-01

    A novel approach of simulating hydromechanical coupling in pore-scale models of porous media is presented in this paper. Parameters of the sandstone samples, such as the stress-strain curve, Poisson's ratio, and permeability under different pore pressure and confining pressure, are tested in laboratory scale. The micro-CT scanner is employed to scan the samples for three-dimensional images, as input to construct the model. Accordingly, four physical models possessing the same pore and rock matrix characteristics as the natural sandstones are developed. Based on the micro-CT images, the three-dimensional finite element models of both rock matrix and pore space are established by MIMICS and ICEM software platform. Navier-Stokes equation and elastic constitutive equation are used as the mathematical model for simulation. A hydromechanical coupling analysis in pore-scale finite element model of porous media is simulated by ANSYS and CFX software. Hereby, permeability of sandstone samples under different pore pressure and confining pressure has been predicted. The simulation results agree well with the benchmark data. Through reproducing its stress state underground, the prediction accuracy of the porous rock permeability in pore-scale simulation is promoted. Consequently, the effects of pore pressure and confining pressure on permeability are revealed from the microscopic view. PMID:24955384

  7. XWeB: The XML Warehouse Benchmark

    Science.gov (United States)

    Mahboubi, Hadj; Darmont, Jérôme

    With the emergence of XML as a standard for representing business data, new decision support applications are being developed. These XML data warehouses aim at supporting On-Line Analytical Processing (OLAP) operations that manipulate irregular XML data. To ensure feasibility of these new tools, important performance issues must be addressed. Performance is customarily assessed with the help of benchmarks. However, decision support benchmarks do not currently support XML features. In this paper, we introduce the XML Warehouse Benchmark (XWeB), which aims at filling this gap. XWeB derives from the relational decision support benchmark TPC-H. It is mainly composed of a test data warehouse that is based on a unified reference model for XML warehouses and that features XML-specific structures, and its associate XQuery decision support workload. XWeB's usage is illustrated by experiments on several XML database management systems.

  8. XWeB: the XML Warehouse Benchmark

    CERN Document Server

    Mahboubi, Hadj

    2011-01-01

    With the emergence of XML as a standard for representing business data, new decision support applications are being developed. These XML data warehouses aim at supporting On-Line Analytical Processing (OLAP) operations that manipulate irregular XML data. To ensure feasibility of these new tools, important performance issues must be addressed. Performance is customarily assessed with the help of benchmarks. However, decision support benchmarks do not currently support XML features. In this paper, we introduce the XML Warehouse Benchmark (XWeB), which aims at filling this gap. XWeB derives from the relational decision support benchmark TPC-H. It is mainly composed of a test data warehouse that is based on a unified reference model for XML warehouses and that features XML-specific structures, and its associate XQuery decision support workload. XWeB's usage is illustrated by experiments on several XML database management systems.

  9. An artificial neural network based fast radiative transfer model for simulating infrared sounder radiances

    Indian Academy of Sciences (India)

    Praveen Krishnan; K Srinivasa Ramanujam; C Balaji

    2012-08-01

    The first step in developing any algorithm to retrieve the atmospheric temperature and humidity parameters at various pressure levels is the simulation of the top of the atmosphere radiances that can be measured by the satellite. This study reports the results of radiative transfer simulations for the multichannel infrared sounder of the proposed Indian satellite INSAT-3D due to be launched shortly. Here, the widely used community software k Compressed Atmospheric Radiative Transfer Algorithm (kCARTA) is employed for performing the radiative transfer simulations. Though well established and benchmarked, kCARTA is a line-by-line solver and hence takes enormous computational time and effort for simulating the multispectral radiances for a given atmospheric scene. This necessitates the development of a much faster and at the same time, equally accurate RT model that can drive a real-time retrieval algorithm. In the present study, a fast radiative transfer model using neural networks is proposed to simulate radiances corresponding to the wavenumbers of INSAT-3D. Realistic atmospheric temperature and humidity profiles have been used for training the network. Spectral response functions of GOES-13, a satellite similar in construction, purpose and design and already in use are used. The fast RT model is able to simulate the radiances for 1200 profiles in 18 ms for a 15-channel GOES profile, with a correlation coefficient of over 99%. Finally, the robustness of the model is tested using additional synthetic profiles generated using empirical orthogonal functions (EOF).

  10. Benchmarking ENDF/B-VII.0

    Science.gov (United States)

    van der Marck, Steven C.

    2006-12-01

    The new major release VII.0 of the ENDF/B nuclear data library has been tested extensively using benchmark calculations. These were based upon MCNP-4C3 continuous-energy Monte Carlo neutronics simulations, together with nuclear data processed using the code NJOY. Three types of benchmarks were used, viz., criticality safety benchmarks, (fusion) shielding benchmarks, and reference systems for which the effective delayed neutron fraction is reported. For criticality safety, more than 700 benchmarks from the International Handbook of Criticality Safety Benchmark Experiments were used. Benchmarks from all categories were used, ranging from low-enriched uranium, compound fuel, thermal spectrum ones (LEU-COMP-THERM), to mixed uranium-plutonium, metallic fuel, fast spectrum ones (MIX-MET-FAST). For fusion shielding many benchmarks were based on IAEA specifications for the Oktavian experiments (for Al, Co, Cr, Cu, LiF, Mn, Mo, Si, Ti, W, Zr), Fusion Neutronics Source in Japan (for Be, C, N, O, Fe, Pb), and Pulsed Sphere experiments at Lawrence Livermore National Laboratory (for 6Li, 7Li, Be, C, N, O, Mg, Al, Ti, Fe, Pb, D 2O, H 2O, concrete, polyethylene and teflon). For testing delayed neutron data more than thirty measurements in widely varying systems were used. Among these were measurements in the Tank Critical Assembly (TCA in Japan) and IPEN/MB-01 (Brazil), both with a thermal spectrum, and two cores in Masurca (France) and three cores in the Fast Critical Assembly (FCA, Japan), all with fast spectra. In criticality safety, many benchmarks were chosen from the category with a thermal spectrum, low-enriched uranium, compound fuel (LEU-COMP-THERM), because this is typical of most current-day reactors, and because these benchmarks were previously underpredicted by as much as 0.5% by most nuclear data libraries (such as ENDF/B-VI.8, JEFF-3.0). The calculated results presented here show that this underprediction is no longer there for ENDF/B-VII.0. The average over 257

  11. Fuzzy delay model based fault simulator for crosstalk delay fault test generation in asynchronous sequential circuits

    Indian Academy of Sciences (India)

    S Jayanthy; M C Bhuvaneswari

    2015-02-01

    In this paper, a fuzzy delay model based crosstalk delay fault simulator is proposed. As design trends move towards nanometer technologies, more number of new parameters affects the delay of the component. Fuzzy delay models are ideal for modelling the uncertainty found in the design and manufacturing steps. The fault simulator based on fuzzy delay detects unstable states, oscillations and non-confluence of settling states in asynchronous sequential circuits. The fuzzy delay model based fault simulator is used to validate the test patterns produced by Elitist Non-dominated sorting Genetic Algorithm (ENGA) based test generator, for detecting crosstalk delay faults in asynchronous sequential circuits. The multi-objective genetic algorithm, ENGA targets two objectives of maximizing fault coverage and minimizing number of transitions. Experimental results are tabulated for SIS benchmark circuits for three gate delay models, namely unit delay model, rise/fall delay model and fuzzy delay model. Experimental results indicate that test validation using fuzzy delay model is more accurate than unit delay model and rise/fall delay model.

  12. Testing turbulent closure models with convection simulations

    CERN Document Server

    Snellman, J E; Mantere, M J; Rheinhardt, M; Dintrans, B

    2012-01-01

    Aims: To compare simple analytical closure models of turbulent Boussinesq convection for stellar applications with direct three-dimensional simulations both in homogeneous and inhomogeneous (bounded) setups. Methods: We use simple analytical closure models to compute the fluxes of angular momentum and heat as a function of rotation rate measured by the Taylor number. We also investigate cases with varying angles between the angular velocity and gravity vectors, corresponding to locating the computational domain at different latitudes ranging from the pole to the equator of the star. We perform three-dimensional numerical simulations in the same parameter regimes for comparison. The free parameters appearing in the closure models are calibrated by two fit methods using simulation data. Unique determination of the closure parameters is possible only in the non-rotating case and when the system is placed at the pole. In the other cases the fit procedures yield somewhat differing results. The quality of the closu...

  13. Benchmarking for Best Practice

    CERN Document Server

    Zairi, Mohamed

    1998-01-01

    Benchmarking for Best Practice uses up-to-the-minute case-studies of individual companies and industry-wide quality schemes to show how and why implementation has succeeded. For any practitioner wanting to establish best practice in a wide variety of business areas, this book makes essential reading. .It is also an ideal textbook on the applications of TQM since it describes concepts, covers definitions and illustrates the applications with first-hand examples. Professor Mohamed Zairi is an international expert and leading figure in the field of benchmarking. His pioneering work in this area l

  14. Deviating From the Benchmarks

    DEFF Research Database (Denmark)

    Rocha, Vera; Van Praag, Mirjam; Carneiro, Anabela

    survival? The analysis is based on a matched employer-employee dataset and covers about 17,500 startups in manufacturing and services. We adopt a new procedure to estimate individual benchmarks for the quantity and quality of initial human resources, acknowledging correlations between hiring decisions...... the benchmark can be substantial, are persistent over time, and hinder the survival of firms. The implications may, however, vary according to the sector and the ownership structure at entry. Given the stickiness of initial choices, wrong human capital decisions at entry turn out to be a close to irreversible...

  15. Benchmarking ICRF Full-wave Solvers for ITER

    Energy Technology Data Exchange (ETDEWEB)

    R. V. Budny, L. Berry, R. Bilato, P. Bonoli, M. Brambilla, R. J. Dumont, A. Fukuyama, R. Harvey, E. F. Jaeger, K. Indireshkumar, E. Lerche, D. McCune, C. K. Phillips, V. Vdovin, J. Wright, and members of the ITPA-IOS

    2011-01-06

    Abstract Benchmarking of full-wave solvers for ICRF simulations is performed using plasma profiles and equilibria obtained from integrated self-consistent modeling predictions of four ITER plasmas. One is for a high performance baseline (5.3 T, 15 MA) DT H-mode. The others are for half-field, half-current plasmas of interest for the pre-activation phase with bulk plasma ion species being either hydrogen or He4. The predicted profiles are used by six full-wave solver groups to simulate the ICRF electromagnetic fields and heating, and by three of these groups to simulate the current-drive. Approximate agreement is achieved for the predicted heating power for the DT and He4 cases. Factor of two disagreements are found for the cases with second harmonic He3 heating in bulk H cases. Approximate agreement is achieved simulating the ICRF current drive.

  16. Sensitivity Analysis of OECD Benchmark Tests in BISON

    Energy Technology Data Exchange (ETDEWEB)

    Swiler, Laura Painton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gamble, Kyle [Idaho National Lab. (INL), Idaho Falls, ID (United States); Schmidt, Rodney C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Williamson, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    This report summarizes a NEAMS (Nuclear Energy Advanced Modeling and Simulation) project focused on sensitivity analysis of a fuels performance benchmark problem. The benchmark problem was defined by the Uncertainty Analysis in Modeling working group of the Nuclear Science Committee, part of the Nuclear Energy Agency of the Organization for Economic Cooperation and Development (OECD ). The benchmark problem involv ed steady - state behavior of a fuel pin in a Pressurized Water Reactor (PWR). The problem was created in the BISON Fuels Performance code. Dakota was used to generate and analyze 300 samples of 17 input parameters defining core boundary conditions, manuf acturing tolerances , and fuel properties. There were 24 responses of interest, including fuel centerline temperatures at a variety of locations and burnup levels, fission gas released, axial elongation of the fuel pin, etc. Pearson and Spearman correlatio n coefficients and Sobol' variance - based indices were used to perform the sensitivity analysis. This report summarizes the process and presents results from this study.

  17. Wind Shear Target Echo Modeling and Simulation

    Directory of Open Access Journals (Sweden)

    Xiaoyang Liu

    2015-01-01

    Full Text Available Wind shear is a dangerous atmospheric phenomenon in aviation. Wind shear is defined as a sudden change of speed or direction of the wind. In order to analyze the influence of wind shear on the efficiency of the airplane, this paper proposes a mathematical model of point target rain echo and weather target signal echo based on Doppler effect. The wind field model is developed in this paper, and the antenna model is also studied by using Bessel function. The spectrum distribution of symmetric and asymmetric wind fields is researched by using the mathematical model proposed in this paper. The simulation results are in accordance with radial velocity component, and the simulation results also confirm the correctness of the established model of antenna.

  18. Nuclear reactor core modelling in multifunctional simulators

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-06-01

    The thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and the use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR-type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and WWER-type APROS core models have been

  19. Battery thermal models for hybrid vehicle simulations

    Science.gov (United States)

    Pesaran, Ahmad A.

    This paper summarizes battery thermal modeling capabilities for: (1) an advanced vehicle simulator (ADVISOR); and (2) battery module and pack thermal design. The National Renewable Energy Laboratory's (NREL's) ADVISOR is developed in the Matlab/Simulink environment. There are several battery models in ADVISOR for various chemistry types. Each one of these models requires a thermal model to predict the temperature change that could affect battery performance parameters, such as resistance, capacity and state of charges. A lumped capacitance battery thermal model in the Matlab/Simulink environment was developed that included the ADVISOR battery performance models. For thermal evaluation and design of battery modules and packs, NREL has been using various computer aided engineering tools including commercial finite element analysis software. This paper will discuss the thermal ADVISOR battery model and its results, along with the results of finite element modeling that were presented at the workshop on "Development of Advanced Battery Engineering Models" in August 2001.

  20. The Semi-active Control of Non-linear Isolation System Based on Smart Isolated Benchmark Model%基于智能隔震结构 Benchmark模型的半主动控制非线性隔震系统

    Institute of Scientific and Technical Information of China (English)

    任安忠; 王学权

    2015-01-01

    This paper elaborates the smart base-isolated benchmark model which is proposed recently in the non-linear isolation system under the control analysis, and mainly introduces the principles of nonlinear phase bench-mark problem and Lyapunov semi-active control.Using the Simulink module in Matlab, we simulated the analysis process and got the control results of Benchmark intelligent isolation structure model in Lyapunov semi-active control;By comparing the results of passive control, the Lyapunov control semi-active control results turn out to be remarkable.%针对最新提出的智能隔震结构Benchmark模型,阐述了其在非线性隔震系统下的控制问题。主要介绍了非线性阶段基准问题和Lyapunov半主动控制的原理,并通过Matlab中Simulink模块( S-函数方法)进行仿真模拟分析,计算得到了智能隔震结构Benchmark模型在Lyapunov半主动控制下的控制结果,与被动控制结果对比可知,Lyapunov半主动控制效果显著。

  1. SUMMARY OF GENERAL WORKING GROUP A+B+D: CODES BENCHMARKING.

    Energy Technology Data Exchange (ETDEWEB)

    WEI, J.; SHAPOSHNIKOVA, E.; ZIMMERMANN, F.; HOFMANN, I.

    2006-05-29

    Computer simulation is an indispensable tool in assisting the design, construction, and operation of accelerators. In particular, computer simulation complements analytical theories and experimental observations in understanding beam dynamics in accelerators. The ultimate function of computer simulation is to study mechanisms that limit the performance of frontier accelerators. There are four goals for the benchmarking of computer simulation codes, namely debugging, validation, comparison and verification: (1) Debugging--codes should calculate what they are supposed to calculate; (2) Validation--results generated by the codes should agree with established analytical results for specific cases; (3) Comparison--results from two sets of codes should agree with each other if the models used are the same; and (4) Verification--results from the codes should agree with experimental measurements. This is the summary of the joint session among working groups A, B, and D of the HI32006 Workshop on computer codes benchmarking.

  2. Benchmark Problems of the Geothermal Technologies Office Code Comparison Study

    Energy Technology Data Exchange (ETDEWEB)

    White, Mark D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Podgorney, Robert [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kelkar, Sharad M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McClure, Mark W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Danko, George [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ghassemi, Ahmad [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fu, Pengcheng [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bahrami, Davood [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Barbier, Charlotte [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cheng, Qinglu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chiu, Kit-Kwan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Detournay, Christine [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elsworth, Derek [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fang, Yi [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Furtney, Jason K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gan, Quan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gao, Qian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Guo, Bin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hao, Yue [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Horne, Roland N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huang, Kai [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Im, Kyungjae [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Norbeck, Jack [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rutqvist, Jonny [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Safari, M. R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sesetty, Varahanaresh [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sonnenthal, Eric [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tao, Qingfeng [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); White, Signe K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wong, Yang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xia, Yidong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-12-02

    A diverse suite of numerical simulators is currently being applied to predict or understand the performance of enhanced geothermal systems (EGS). To build confidence and identify critical development needs for these analytical tools, the United States Department of Energy, Geothermal Technologies Office has sponsored a Code Comparison Study (GTO-CCS), with participants from universities, industry, and national laboratories. A principal objective for the study was to create a community forum for improvement and verification of numerical simulators for EGS modeling. Teams participating in the study were those representing U.S. national laboratories, universities, and industries, and each team brought unique numerical simulation capabilities to bear on the problems. Two classes of problems were developed during the study, benchmark problems and challenge problems. The benchmark problems were structured to test the ability of the collection of numerical simulators to solve various combinations of coupled thermal, hydrologic, geomechanical, and geochemical processes. This class of problems was strictly defined in terms of properties, driving forces, initial conditions, and boundary conditions. Study participants submitted solutions to problems for which their simulation tools were deemed capable or nearly capable. Some participating codes were originally developed for EGS applications whereas some others were designed for different applications but can simulate processes similar to those in EGS. Solution submissions from both were encouraged. In some cases, participants made small incremental changes to their numerical simulation codes to address specific elements of the problem, and in other cases participants submitted solutions with existing simulation tools, acknowledging the limitations of the code. The challenge problems were based on the enhanced geothermal systems research conducted at Fenton Hill, near Los Alamos, New Mexico, between 1974 and 1995. The problems

  3. Benchmarks: WICHE Region 2012

    Science.gov (United States)

    Western Interstate Commission for Higher Education, 2013

    2013-01-01

    Benchmarks: WICHE Region 2012 presents information on the West's progress in improving access to, success in, and financing of higher education. The information is updated annually to monitor change over time and encourage its use as a tool for informed discussion in policy and education communities. To establish a general context for the…

  4. HPCS HPCchallenge Benchmark Suite

    Science.gov (United States)

    2007-11-02

    measured HPCchallenge Benchmark performance on various HPC architectures — from Cray X1s to Beowulf clusters — in the presentation and paper...from Cray X1s to Beowulf clusters — using the updated results at http://icl.cs.utk.edu/hpcc/hpcc_results.cgi Even a small percentage of random

  5. Surveys and Benchmarks

    Science.gov (United States)

    Bers, Trudy

    2012-01-01

    Surveys and benchmarks continue to grow in importance for community colleges in response to several factors. One is the press for accountability, that is, for colleges to report the outcomes of their programs and services to demonstrate their quality and prudent use of resources, primarily to external constituents and governing boards at the state…

  6. Operational benchmarking of Japanese and Danish hopsitals

    DEFF Research Database (Denmark)

    Traberg, Andreas; Itoh, Kenji; Jacobsen, Peter

    2010-01-01

    This benchmarking model is designed as an integration of three organizational dimensions suited for the healthcare sector. The model incorporates posterior operational indicators, and evaluates upon aggregation of performance. The model is tested upon seven cases from Japan and Denmark. Japanese...

  7. Biological transportation networks: Modeling and simulation

    KAUST Repository

    Albi, Giacomo

    2015-09-15

    We present a model for biological network formation originally introduced by Cai and Hu [Adaptation and optimization of biological transport networks, Phys. Rev. Lett. 111 (2013) 138701]. The modeling of fluid transportation (e.g., leaf venation and angiogenesis) and ion transportation networks (e.g., neural networks) is explained in detail and basic analytical features like the gradient flow structure of the fluid transportation network model and the impact of the model parameters on the geometry and topology of network formation are analyzed. We also present a numerical finite-element based discretization scheme and discuss sample cases of network formation simulations.

  8. EXACT SIMULATION OF A BOOLEAN MODEL

    Directory of Open Access Journals (Sweden)

    Christian Lantuéjoul

    2013-06-01

    Full Text Available A Boolean model is a union of independent objects (compact random subsets located at Poisson points. Two algorithms are proposed for simulating a Boolean model in a bounded domain. The first one applies only to stationary models. It generates the objects prior to their Poisson locations. Two examples illustrate its applicability. The second algorithm applies to stationary and non-stationary models. It generates the Poisson points prior to the objects. Its practical difficulties of implementation are discussed. Both algorithms are based on importance sampling techniques, and the generated objects are weighted.

  9. Benchmark study between FIDAP and a cellular automata code

    Science.gov (United States)

    Akau, R. L.; Stockman, H. W.

    A fluid flow benchmark exercise was conducted to compare results between a cellular automata code and FIDAP. Cellular automata codes are free from gridding constraints, and are generally used to model slow (Reynolds number approximately 1) flows around complex solid obstacles. However, the accuracy of cellular automata codes at higher Reynolds numbers, where inertial terms are significant, is not well-documented. In order to validate the cellular automata code, two fluids problems were investigated. For both problems, flow was assumed to be laminar, two-dimensional, isothermal, incompressible and periodic. Results showed that the cellular automata code simulated the overall behavior of the flow field.

  10. Full sphere hydrodynamic and dynamo benchmarks

    KAUST Repository

    Marti, P.

    2014-01-26

    Convection in planetary cores can generate fluid flow and magnetic fields, and a number of sophisticated codes exist to simulate the dynamic behaviour of such systems. We report on the first community activity to compare numerical results of computer codes designed to calculate fluid flow within a whole sphere. The flows are incompressible and rapidly rotating and the forcing of the flow is either due to thermal convection or due to moving boundaries. All problems defined have solutions that alloweasy comparison, since they are either steady, slowly drifting or perfectly periodic. The first two benchmarks are defined based on uniform internal heating within the sphere under the Boussinesq approximation with boundary conditions that are uniform in temperature and stress-free for the flow. Benchmark 1 is purely hydrodynamic, and has a drifting solution. Benchmark 2 is a magnetohydrodynamic benchmark that can generate oscillatory, purely periodic, flows and magnetic fields. In contrast, Benchmark 3 is a hydrodynamic rotating bubble benchmark using no slip boundary conditions that has a stationary solution. Results from a variety of types of code are reported, including codes that are fully spectral (based on spherical harmonic expansions in angular coordinates and polynomial expansions in radius), mixed spectral and finite difference, finite volume, finite element and also a mixed Fourier-finite element code. There is good agreement between codes. It is found that in Benchmarks 1 and 2, the approximation of a whole sphere problem by a domain that is a spherical shell (a sphere possessing an inner core) does not represent an adequate approximation to the system, since the results differ from whole sphere results. © The Authors 2014. Published by Oxford University Press on behalf of The Royal Astronomical Society.

  11. Love Kills:. Simulations in Penna Ageing Model

    Science.gov (United States)

    Stauffer, Dietrich; Cebrat, Stanisław; Penna, T. J. P.; Sousa, A. O.

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

  12. Simulation Versus Models: Which One and When?

    Science.gov (United States)

    Dorn, William S.

    1975-01-01

    Describes two types of computer-based experiments: simulation (which assumes no student knowledge of the workings of the computer program) is recommended for experiments aimed at inductive reasoning; and modeling (which assumes student understanding of the computer program) is recommended for deductive processes. (MLH)

  13. Modeling and simulation of epidemic spread

    DEFF Research Database (Denmark)

    Shatnawi, Maad; Lazarova-Molnar, Sanja; Zaki, Nazar

    2013-01-01

    and control such epidemics. This paper presents an overview of the epidemic spread modeling and simulation, and summarizes the main technical challenges in this field. It further investigates the most relevant recent approaches carried out towards this perspective and provides a comparison and classification...

  14. Modeling and Simulating Virtual Anatomical Humans

    NARCIS (Netherlands)

    Madehkhaksar, Forough; Luo, Zhiping; Pronost, Nicolas; Egges, Arjan

    2014-01-01

    This chapter presents human musculoskeletal modeling and simulation as a challenging field that lies between biomechanics and computer animation. One of the main goals of computer animation research is to develop algorithms and systems that produce plausible motion. On the other hand, the main chall

  15. Twitter's tweet method modelling and simulation

    Science.gov (United States)

    Sarlis, Apostolos S.; Sakas, Damianos P.; Vlachos, D. S.

    2015-02-01

    This paper seeks to purpose the concept of Twitter marketing methods. The tools that Twitter provides are modelled and simulated using iThink in the context of a Twitter media-marketing agency. The paper has leveraged the system's dynamic paradigm to conduct Facebook marketing tools and methods modelling, using iThink™ system to implement them. It uses the design science research methodology for the proof of concept of the models and modelling processes. The following models have been developed for a twitter marketing agent/company and tested in real circumstances and with real numbers. These models were finalized through a number of revisions and iterators of the design, develop, simulate, test and evaluate. It also addresses these methods that suit most organized promotion through targeting, to the Twitter social media service. The validity and usefulness of these Twitter marketing methods models for the day-to-day decision making are authenticated by the management of the company organization. It implements system dynamics concepts of Twitter marketing methods modelling and produce models of various Twitter marketing situations. The Tweet method that Twitter provides can be adjusted, depending on the situation, in order to maximize the profit of the company/agent.

  16. NASA Software Engineering Benchmarking Effort

    Science.gov (United States)

    Godfrey, Sally; Rarick, Heather

    2012-01-01

    Benchmarking was very interesting and provided a wealth of information (1) We did see potential solutions to some of our "top 10" issues (2) We have an assessment of where NASA stands with relation to other aerospace/defense groups We formed new contacts and potential collaborations (1) Several organizations sent us examples of their templates, processes (2) Many of the organizations were interested in future collaboration: sharing of training, metrics, Capability Maturity Model Integration (CMMI) appraisers, instructors, etc. We received feedback from some of our contractors/ partners (1) Desires to participate in our training; provide feedback on procedures (2) Welcomed opportunity to provide feedback on working with NASA

  17. Multiphase reacting flows modelling and simulation

    CERN Document Server

    Marchisio, Daniele L

    2007-01-01

    The papers in this book describe the most widely applicable modeling approaches and are organized in six groups covering from fundamentals to relevant applications. In the first part, some fundamentals of multiphase turbulent reacting flows are covered. In particular the introduction focuses on basic notions of turbulence theory in single-phase and multi-phase systems as well as on the interaction between turbulence and chemistry. In the second part, models for the physical and chemical processes involved are discussed. Among other things, particular emphasis is given to turbulence modeling strategies for multiphase flows based on the kinetic theory for granular flows. Next, the different numerical methods based on Lagrangian and/or Eulerian schemes are presented. In particular the most popular numerical approaches of computational fluid dynamics codes are described (i.e., Direct Numerical Simulation, Large Eddy Simulation, and Reynolds-Averaged Navier-Stokes approach). The book will cover particle-based meth...

  18. Modeling, simulation and optimization of bipedal walking

    CERN Document Server

    Berns, Karsten

    2013-01-01

    The model-based investigation of motions of anthropomorphic systems is an important interdisciplinary research topic involving specialists from many fields such as Robotics, Biomechanics, Physiology, Orthopedics, Psychology, Neurosciences, Sports, Computer Graphics and Applied Mathematics. This book presents a study of basic locomotion forms such as walking and running is of particular interest due to the high demand on dynamic coordination, actuator efficiency and balance control. Mathematical models and numerical simulation and optimization techniques are explained, in combination with experimental data, which can help to better understand the basic underlying mechanisms of these motions and to improve them. Example topics treated in this book are Modeling techniques for anthropomorphic bipedal walking systems Optimized walking motions for different objective functions Identification of objective functions from measurements Simulation and optimization approaches for humanoid robots Biologically inspired con...

  19. Modelling and simulation of affinity membrane adsorption.

    Science.gov (United States)

    Boi, Cristiana; Dimartino, Simone; Sarti, Giulio C

    2007-08-24

    A mathematical model for the adsorption of biomolecules on affinity membranes is presented. The model considers convection, diffusion and adsorption kinetics on the membrane module as well as the influence of dead end volumes and lag times; an analysis of flow distribution on the whole system is also included. The parameters used in the simulations were obtained from equilibrium and dynamic experimental data measured for the adsorption of human IgG on A2P-Sartoepoxy affinity membranes. The identification of a bi-Langmuir kinetic mechanisms for the experimental system investigated was paramount for a correct process description and the simulated breakthrough curves were in good agreement with the experimental data. The proposed model provides a new insight into the phenomena involved in the adsorption on affinity membranes and it is a valuable tool to assess the use of membrane adsorbers in large scale processes.

  20. A Superbubble Feedback Model for Galaxy Simulations

    CERN Document Server

    Keller, B W; Benincasa, S M; Couchman, H M P

    2014-01-01

    We present a new stellar feedback model that reproduces superbubbles. Superbubbles from clustered young stars evolve quite differently to individual supernovae and are substantially more efficient at generating gas motions. The essential new components of the model are thermal conduction, sub-grid evaporation and a sub-grid multi-phase treatment for cases where the simulation mass resolution is insufficient to model the early stages of the superbubble. The multi-phase stage is short compared to superbubble lifetimes. Thermal conduction physically regulates the hot gas mass without requiring a free parameter. Accurately following the hot component naturally avoids overcooling. Prior approaches tend to heat too much mass, leaving the hot ISM below $10^6$ K and susceptible to rapid cooling unless ad-hoc fixes were used. The hot phase also allows feedback energy to correctly accumulate from multiple, clustered sources, including stellar winds and supernovae. We employ high-resolution simulations of a single star ...