WorldWideScience

Sample records for interaction models comparison

  1. Turbulent Chemical Interaction Models in NCC: Comparison

    Science.gov (United States)

    Norris, Andrew T.; Liu, Nan-Suey

    2006-01-01

    The performance of a scalar PDF hydrogen-air combustion model in predicting a complex reacting flow is evaluated. In addition the results are compared to those obtained by running the same case with the so-called laminar chemistry model and also a new model based on the concept of mapping partially stirred reactor data onto perfectly stirred reactor data. The results show that the scalar PDF model produces significantly different results from the other two models, and at a significantly higher computational cost.

  2. Interactive comparison of hypothesis tests for statistical model checking

    NARCIS (Netherlands)

    de Boer, Pieter-Tjerk; Reijsbergen, D.P.; Scheinhardt, Willem R.W.

    2015-01-01

    We present a web-based interactive comparison of hypothesis tests as are used in statistical model checking, providing users and tool developers with more insight into their characteristics. Parameters can be modified easily and their influence is visualized in real time; an integrated simulation

  3. Sevoflurane Remifentanil Interaction Comparison of Different Response Surface Models

    NARCIS (Netherlands)

    Heyse, Bjorn; Proost, Johannes H.; Schumacher, Peter M.; Bouillon, Thomas W.; Vereecke, Hugo E. M.; Eleveld, Douglas J.; Luginbuehl, Martin; Struys, Michel M. R. F.

    2012-01-01

    Background: Various pharmacodynamic response surface models have been developed to quantitatively describe the relationship between two or more drug concentrations with their combined clinical effect. We examined the interaction of remifentanil and sevoflurane on the probability of tolerance to shak

  4. Biotic Interactions in the Face of Climate Change: A Comparison of Three Modelling Approaches

    Science.gov (United States)

    Jaeschke, Anja; Bittner, Torsten; Jentsch, Anke; Reineking, Björn; Schlumprecht, Helmut; Beierkuhnlein, Carl

    2012-01-01

    Climate change is expected to alter biotic interactions, and may lead to temporal and spatial mismatches of interacting species. Although the importance of interactions for climate change risk assessments is increasingly acknowledged in observational and experimental studies, biotic interactions are still rarely incorporated in species distribution models. We assessed the potential impacts of climate change on the obligate interaction between Aeshna viridis and its egg-laying plant Stratiotes aloides in Europe, based on an ensemble modelling technique. We compared three different approaches for incorporating biotic interactions in distribution models: (1) We separately modelled each species based on climatic information, and intersected the future range overlap (‘overlap approach’). (2) We modelled the potential future distribution of A. viridis with the projected occurrence probability of S. aloides as further predictor in addition to climate (‘explanatory variable approach’). (3) We calibrated the model of A. viridis in the current range of S. aloides and multiplied the future occurrence probabilities of both species (‘reference area approach’). Subsequently, all approaches were compared to a single species model of A. viridis without interactions. All approaches projected a range expansion for A. viridis. Model performance on test data and amount of range gain differed depending on the biotic interaction approach. All interaction approaches yielded lower range gains (up to 667% lower) than the model without interaction. Regarding the contribution of algorithm and approach to the overall uncertainty, the main part of explained variation stems from the modelling algorithm, and only a small part is attributed to the modelling approach. The comparison of the no-interaction model with the three interaction approaches emphasizes the importance of including obligate biotic interactions in projective species distribution modelling. We recommend the use of

  5. Susceptibilities in the PNJL model with 8q interactions and comparison with lQCD

    CERN Document Server

    Moreira, João; Osipov, Alexander; Blin, Alex

    2013-01-01

    We present some results pertaining quantities which are regarded as good indicators of the pseudo-critical temperatures for the deconfinement and partial chiral restoration transitions using a polynomial form for the Polyakov potential part and an extended version of the NJL model which includes 6 and 8 quark interaction terms. Some comparisons with results from the lattice formulation of QCD (lQCD) are performed and results for the location of the critical endoint in the phase diagram are also presented. It is shown that the comparison with lQCD results favors a moderately strong OZI-violating 8 quark interaction term.

  6. QGSjet II and EPOS hadronic interaction models: comparison with the Yakutsk EAS array data

    Energy Technology Data Exchange (ETDEWEB)

    Knurenko, S.P.; Sabourov, A.V. [Yu. G. Shafer Institute for Cosmophysical Research and Aeronomy (Russian Federation)

    2009-12-15

    Various hadronic interaction models were used in extensive air showers simulations. This resulted in ambiguous estimation of primary energy, cosmic ray flux intensity, mass composition, etc. Several revisions of models have been made recently; for example, third major version of QGSjet II (QGSjet II-03) model was released, new models based on actual accelerator data appeared (EPOS). Employment of newer models always leads to new comprehension of experimental results. Nevertheless, in this case there still is some ambiguity. It is a matter of how correct does the model extrapolate characteristics of primary particle interaction with nuclei of the air from high energies to ultra-high.

  7. A comparison of model helicopter rotor Primary and Secondary blade/vortex interaction blade slap

    Science.gov (United States)

    Hubbard, J. E., Jr.; Leighton, K. P.

    1983-01-01

    A study of the relative importance of blade/vortex interactions which occur on the retreating side of a model helicopter rotor disk is described. Some of the salient characteristics of this phenomenon are presented and discussed. It is shown that the resulting Secondary blade slap may be of equal or greater intensity than the advancing side (Primary) blade slap. Instrumented model helicopter rotor data is presented which reveals the nature of the retreating blade/vortex interaction. The importance of Secondary blade slap as it applies to predictive techniques or approaches is discussed. When Secondary blade slap occurs it acts to enlarge the window of operating conditions for which blade slap exists.

  8. Synergism between rocuronium and cisatracurium: comparison of the Minto and Greco interaction models

    Science.gov (United States)

    Kwon, Jae Young; Kim, Hae-Kyu

    2016-01-01

    Background This study was conducted to investigate the pharmacodynamic interaction between rocuronium and cisatracurium using the response surface model, which is not subject to the limitations of traditional isobolographic analysis. Methods One hundred and twenty patients were randomly allocated to receive one of the fifteen predefined combinations of rocuronium and cisatracurium. To study single drugs, cisatracurium 0.2, 0.15, or 0.1 mg/kg or rocuronium 0.8, 0.6 or 0.4 mg/kg doses were administered alone. To study the pharmacodynamic interaction, drugs were applied in three types of combination ratio, i.e., half dose of each drug alone, 75% of each single dose of rocuronium and 25% of each single dose of cisatracurium, and vice versa. Train-of-four (TOF) ratio and T1% (first twitch of the TOF presented as percentage compared to the initial T1) were used as pharmacodynamic endpoints, and the Greco and Minto models were used as surface interaction models. Results The interaction term α of the Greco model for TOF ratio and T1% measurements showed synergism with values of 0.977 and 1.12, respectively. Application of the Minto model resulted in U50 (θ) values (normalized unit of concentration that produces 50% of the maximal effect in the 0 < θ < 1 region) less than 1 for both TOF ratio and T1% measurements, indicating that rocuronium and cisatracurium exhibit synergism. Conclusions Response surface modeling of the interaction between rocuronium and cisatracurium, based on considerations of their effects on muscle relaxation as measured by TOF ratio and T1%, indicated that the two drugs show considerable synergism. PMID:27482310

  9. Model comparison in ANOVA.

    Science.gov (United States)

    Rouder, Jeffrey N; Engelhardt, Christopher R; McCabe, Simon; Morey, Richard D

    2016-12-01

    Analysis of variance (ANOVA), the workhorse analysis of experimental designs, consists of F-tests of main effects and interactions. Yet, testing, including traditional ANOVA, has been recently critiqued on a number of theoretical and practical grounds. In light of these critiques, model comparison and model selection serve as an attractive alternative. Model comparison differs from testing in that one can support a null or nested model vis-a-vis a more general alternative by penalizing more flexible models. We argue this ability to support more simple models allows for more nuanced theoretical conclusions than provided by traditional ANOVA F-tests. We provide a model comparison strategy and show how ANOVA models may be reparameterized to better address substantive questions in data analysis.

  10. Inter-Comparison and Validation of Geant4 Photon Interaction Models

    CERN Document Server

    Augelli, M; Pia, M G; Queiroz, P P; Quintieri, L; Souza-Santos, D; Sudhakar, M; Saracco, P; Weidenspointner, G; Zoglauer, A

    2009-01-01

    A R&D project, named Nano5, has been recently launched to study an architectural design in view of addressing new experimental issues related to particle transport in high energy physics and other related physics disciplines with Geant4. In this frame, the first step has involved the redesign of the photon interaction models currently available in Geant4; this task has motivated a thorough investigation of the physics and computational features of these models, whose first results are presented here.

  11. A Comparison of Interactively Coupled Paleoclimate-Vegetation Models With the Vegetation Record

    Science.gov (United States)

    Batra, P.; Pollard, D.; Barron, E.

    2001-05-01

    Climate-vegetation interactions are a key ingredient in understanding Earth system history. Vegetation models used to explore past climate and past vegetation distributions are largely based on modern plant-climate relationships. This study explores the application of four such models, each built upon different assumptions and parameters, and determines how well each model reproduces past records. In addition, this approach enables an exploration of the potential influence of vegetation on paleoclimates. The four vegetation models (the BIOME 3.5 model of Haxeltine and Prentice (1996), the simple dynamic vegetation model of Cosgrove (1998), the EVE model of Bergengren et al. (2001) and the IBIS model of Foley et al. (1996)) were run interactively with a general circulation model (GCM) of the atmosphere for four time periods. The GCM utilized is GENESIS 2.0, designed for paleoclimate studies. The four time periods for which all four vegetation models are employed are the Early Miocene, Oxygen Isotope Stage Three (warm and cool phases) between 30,000 and 42,000 years ago, and the Last Glacial Maximum. Differences between parameterizations include differences in the number of vegetation types in each model, the inclusion in some models of the influence of atmospheric CO2 levels on the growth of C3 versus C4 vegetation and on stomatal conductance, and whether the models focus on the equilibrium or dynamic state of ecosystems. Preliminary results indicate only small differences in globally-averaged mean annual temperature and precipitation values, suggesting that all models have almost the same effect on the climate. There are differences, however, in how accurately each model reproduces the paleorecord. For example, in the Miocene simulations, when compared to the data of Wolfe (1985), the SDVM model underpredicts the presence of deciduous vegetation in North America, while the EVE model underpredicts the presence of coniferous forest in Eurasia. In the Last Glacial

  12. MHD Model Results of Solar Wind Plasma Interaction with Mars and Comparison with MAVEN Observations

    Science.gov (United States)

    Ma, Y. J.; Russell, C. T.; Nagy, A. F.; Toth, G.; Halekas, J. S.; Connerney, J. E. P.; Espley, J. R.; Mahaffy, P. R.

    2015-01-01

    The crustal remnant field on Mars rotates constantly with the planet, varying the magnetic field configuration interacting with the solar wind. It has been found that ion loss rates slowly vary with the subsolar longitude, anticorrelating with the intensity of the dayside crustal field source, with some time delay, using a time-dependent multispecies MHD model. In this study, we investigate in detail how plasma properties are influenced locally by the crustal field and its rotation. Model results will be compared in detail with plasma observations from MAVEN.

  13. Results of an interactively coupled atmospheric chemistry - general circulation model. Comparison with observations

    Energy Technology Data Exchange (ETDEWEB)

    Hein, R.; Dameris, M.; Schnadt, C. [and others

    2000-01-01

    An interactively coupled climate-chemistry model which enables a simultaneous treatment of meteorology and atmospheric chemistry and their feedbacks is presented. This is the first model, which interactively combines a general circulation model based on primitive equations with a rather complex model of stratospheric and tropospheric chemistry, and which is computational efficient enough to allow long-term integrations with currently available computer resources. The applied model version extends from the Earth's surface up to 10 hPa with a relatively high number (39) of vertical levels. We present the results of a present-day (1990) simulation and compare it to available observations. We focus on stratospheric dynamics and chemistry relevant to describe the stratospheric ozone layer. The current model version ECHAM4.L39(DLR)/CHEM can realistically reproduce stratospheric dynamics in the Arctic vortex region, including stratospheric warming events. This constitutes a major improvement compared to formerly applied model versions. However, apparent shortcomings in Antarctic circulation and temperatures persist. The seasonal and interannual variability of the ozone layer is simulated in accordance with observations. Activation and deactivation of chlorine in the polar stratospheric vortices and their interhemispheric differences are reproduced. The consideration of the chemistry feedback on dynamics results in an improved representation of the spatial distribution of stratospheric water vapor concentrations, i.e., the simulated meriodional water vapor gradient in the stratosphere is realistic. The present model version constitutes a powerful tool to investigate, for instance, the combined direct and indirect effects of anthropogenic trace gas emissions, and the future evolution of the ozone layer. (orig.)

  14. Results of an interactively coupled atmospheric chemistry - general circulation model. Comparison with observations

    Energy Technology Data Exchange (ETDEWEB)

    Hein, R.; Dameris, M.; Schnadt, C. [and others

    2000-01-01

    An interactively coupled climate-chemistry model which enables a simultaneous treatment of meteorology and atmospheric chemistry and their feedbacks is presented. This is the first model, which interactively combines a general circulation model based on primitive equations with a rather complex model of stratospheric and tropospheric chemistry, and which is computational efficient enough to allow long-term integrations with currently available computer resources. The applied model version extends from the Earth's surface up to 10 hPa with a relatively high number (39) of vertical levels. We present the results of a present-day (1990) simulation and compare it to available observations. We focus on stratospheric dynamics and chemistry relevant to describe the stratospheric ozone layer. The current model version ECHAM4.L39(DLR)/CHEM can realistically reproduce stratospheric dynamics in the Arctic vortex region, including stratospheric warming events. This constitutes a major improvement compared to formerly applied model versions. However, apparent shortcomings in Antarctic circulation and temperatures persist. The seasonal and interannual variability of the ozone layer is simulated in accordance with observations. Activation and deactivation of chlorine in the polar stratospheric vortices and their interhemispheric differences are reproduced. The consideration of the chemistry feedback on dynamics results in an improved representation of the spatial distribution of stratospheric water vapor concentrations, i.e., the simulated meriodional water vapor gradient in the stratosphere is realistic. The present model version constitutes a powerful tool to investigate, for instance, the combined direct and indirect effects of anthropogenic trace gas emissions, and the future evolution of the ozone layer. (orig.)

  15. Fluid structure interaction of patient specific abdominal aortic aneurysms: a comparison with solid stress models

    Directory of Open Access Journals (Sweden)

    Thom Simon A

    2006-05-01

    Full Text Available Abstract Background Abdominal aortic aneurysm (AAA is a dilatation of the aortic wall, which can rupture, if left untreated. Previous work has shown that, maximum diameter is not a reliable determinant of AAA rupture. However, it is currently the most widely accepted indicator. Wall stress may be a better indicator and promising patient specific results from structural models using static pressure, have been published. Since flow and pressure inside AAA are non-uniform, the dynamic interaction between the pulsatile flow and wall may influence the predicted wall stress. The purpose of the present study was to compare static and dynamic wall stress analysis of patient specific AAAs. Method Patient-specific AAA models were created from CT scans of three patients. Two simulations were performed on each lumen model, fluid structure interaction (FSI model and static structural (SS model. The AAA wall was created by dilating the lumen with a uniform 1.5 mm thickness, and was modeled as a non-linear hyperelastic material. Commercial finite element code Adina 8.2 was used for all simulations. The results were compared between the FSI and SS simulations. Results Results are presented for the wall stress patterns, wall shear stress patterns, pressure, and velocity fields within the lumen. It is demonstrated that including fluid flow can change local wall stresses slightly. However, as far as the peak wall stress is concerned, this effect is negligible as the difference between SS and FSI models is less than 1%. Conclusion The results suggest that fully coupled FSI simulation, which requires considerable computational power to run, adds little to rupture risk prediction. This justifies the use of SS models in previous studies.

  16. Cross-comparison of spacecraft-environment interaction model predictions applied to Solar Probe Plus near perihelion

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, R. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada); Miyake, Y.; Usui, H. [Graduate School of System Informatics, Kobe University, Kobe 657-8501 (Japan); Deca, J.; Lapenta, G. [Centre for Mathematical Plasma Astrophysics, Mathematics Department, KU Leuven, Celestijnenlaan 200B bus 2400, 3001 Leuven (Belgium); Matéo-Vélez, J. C. [Department of Space Environment, Onera—The French Aerospace Lab, Toulouse (France); Ergun, R. E.; Sturner, A. [Department of Astrophysical and Planetary Science, University of Colorado, Boulder, Colorado 80309 (United States); Génot, V. [Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, France and CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028 Toulouse cedex 4 (France); Hilgers, A. [ESA, ESTEC, Keplerlaan 1, PO Box 299, 2200 AG Noordwijk (Netherlands); Markidis, S. [High Performance Computing and Visualization Department, KTH Royal Institute of Technology, Stockholm (Sweden)

    2014-06-15

    Five spacecraft-plasma models are used to simulate the interaction of a simplified geometry Solar Probe Plus (SPP) satellite with the space environment under representative solar wind conditions near perihelion. By considering similarities and differences between results obtained with different numerical approaches under well defined conditions, the consistency and validity of our models can be assessed. The impact on model predictions of physical effects of importance in the SPP mission is also considered by comparing results obtained with and without these effects. Simulation results are presented and compared with increasing levels of complexity in the physics of interaction between solar environment and the SPP spacecraft. The comparisons focus particularly on spacecraft floating potentials, contributions to the currents collected and emitted by the spacecraft, and on the potential and density spatial profiles near the satellite. The physical effects considered include spacecraft charging, photoelectron and secondary electron emission, and the presence of a background magnetic field. Model predictions obtained with our different computational approaches are found to be in agreement within 2% when the same physical processes are taken into account and treated similarly. The comparisons thus indicate that, with the correct description of important physical effects, our simulation models should have the required skill to predict details of satellite-plasma interaction physics under relevant conditions, with a good level of confidence. Our models concur in predicting a negative floating potential V{sub fl}∼−10V for SPP at perihelion. They also predict a “saturated emission regime” whereby most emitted photo- and secondary electron will be reflected by a potential barrier near the surface, back to the spacecraft where they will be recollected.

  17. Dynamics of wave-current-surge interactions in Lake Michigan: A model comparison

    Science.gov (United States)

    Mao, Miaohua; Xia, Meng

    2017-02-01

    Wave, storm surge dynamics, and wave-current-surge interactions (WCSI) were investigated by applying a pair of unstructured-grid-based models to Lake Michigan under two strong wind events. The effects of wind field sources, wind drag coefficient bulk formula, and parameterizations of the bottom friction term were explored to understand lake dynamics. Two wave models were calibrated by using alternative wave physics settings under the 2011 northeasterly wind event. Forced by the southwesterly wind event in 2013, the calibrated models using the atmosphere-ocean fully coupled Climate Forecast System Version 2 wind field were further validated. It is found that the northwesterly winds induced 0.57 m setup near the southwestern coast, whereas the southwesterly winds produced 0.28 m setup and -0.43 m setdown near the northern and southwestern coasts, respectively. The WCSI mostly influence waves and storm surge in shallow-water areas near coasts and islands through depth-induced breaking, current-induced frequency shift and refraction, and wave-induced setup/setdown through wave radiation stress. Owing to the adoption of different discretization algorithms and bottom friction formulations, the modeled storm surge and waves exhibit some variation between the paired models. Even though the storm surge difference with and without WCSI is smaller than that between the two WCSI-coupled models, both circulation models adopt WCSI considering their consistent improvement on model accuracy under both wind events. The analysis of water transport indicates that wind speed, direction, and coastal geometry and bathymetry are also important factors in storm surge.

  18. A comparison of different stability models for genotype x environment interaction in pearl millet

    Directory of Open Access Journals (Sweden)

    S. S. Pabale and H. R. Pandya

    2010-09-01

    Full Text Available Twenty four genotypes (hybrids of pearl millet were tested under eight environments in Gujarat. The models of Eberhart andRussell (1966, Perkins and Jinks (1968 and Freeman and Perkins (1971 applied to study genotype x environment interactionand were compared for their efficiency empirically. The genotypes GHB-788, GHB-832 and GHB-840 were observed as moststable and widely adapted over environments in all three models. On the basis of simplicity and computational convenience,Eberhart and Russell (1966 model was recommended.

  19. Comparison of two thermal spike models for ion-solid interaction

    Energy Technology Data Exchange (ETDEWEB)

    Szenes, G., E-mail: szenes@ludens.elte.h [Department of Materials Physics, Eoetvoes University, P.O. Box 32, H-1518 Budapest (Hungary)

    2011-01-15

    A comparative review of the inelastic thermal spike model (ITSM, Meftah et al., 1994) and the analytical thermal spike model (ATSM Szenes, 1995) is given. The ITSM follows the formation of the ion-induced thermal spike based on the Fourier equation while the ATSM skips this stage and a final Gaussian temperature distribution is assumed. Each of the two models doubts the basic assumptions of the other. The ITSM rejects the Gaussian temperature distribution while according to ATSM several thermophysical parameters used by the ITSM are irrelevant to the formation of the thermal spike and the equilibrium values are not valid under spike conditions. The essentially different conclusions of the models are discussed in connection with experiments performed in BaFe{sub 12}O{sub 19}, Al{sub 2}O{sub 3}, silica and high-T{sub c} superconductors.

  20. Comparison of two thermal spike models for ion-solid interaction

    Science.gov (United States)

    Szenes, G.

    2011-01-01

    A comparative review of the inelastic thermal spike model (ITSM, Meftah et al., 1994) and the analytical thermal spike model (ATSM Szenes, 1995) is given. The ITSM follows the formation of the ion-induced thermal spike based on the Fourier equation while the ATSM skips this stage and a final Gaussian temperature distribution is assumed. Each of the two models doubts the basic assumptions of the other. The ITSM rejects the Gaussian temperature distribution while according to ATSM several thermophysical parameters used by the ITSM are irrelevant to the formation of the thermal spike and the equilibrium values are not valid under spike conditions. The essentially different conclusions of the models are discussed in connection with experiments performed in BaFe 12O 19, Al 2O 3, silica and high- T c superconductors.

  1. Tests of Simple Slopes in Multiple Regression Models with an Interaction: Comparison of Four Approaches.

    Science.gov (United States)

    Liu, Yu; West, Stephen G; Levy, Roy; Aiken, Leona S

    2017-01-01

    In multiple regression researchers often follow up significant tests of the interaction between continuous predictors X and Z with tests of the simple slope of Y on X at different sample-estimated values of the moderator Z (e.g., ±1 SD from the mean of Z). We show analytically that when X and Z are randomly sampled from the population, the variance expression of the simple slope at sample-estimated values of Z differs from the traditional variance expression obtained when the values of X and Z are fixed. A simulation study using randomly sampled predictors compared four approaches: (a) the Aiken and West ( 1991 ) test of simple slopes at fixed population values of Z, (b) the Aiken and West test at sample-estimated values of Z, (c) a 95% percentile bootstrap confidence interval approach, and (d) a fully Bayesian approach with diffuse priors. The results showed that approach (b) led to inflated Type 1 error rates and 95% confidence intervals with inadequate coverage rates, whereas other approaches maintained acceptable Type 1 error rates and adequate coverage of confidence intervals. Approach (c) had asymmetric rejection rates at small sample sizes. We used an empirical data set to illustrate these approaches.

  2. Comparison of hadron production in Monte-Carlo models and experimental data in p+p interactions at the SPS energies

    CERN Document Server

    Ilnicka, Agnieszka

    The aim of this thesis is the comparison of the particle production in proton-proton interactions simulated by Monte Carlo (MC) models used in NA61/SHINE collaboration: EPOS and VENUS with the available experimental data. The analysis of total multiplic- ities of strange particles (, , K 0 s , K + and K

  3. Comparison of 2 models for gene-environment interactions: an example of simulated gene-medication interactions on systolic blood pressure in family-based data.

    Science.gov (United States)

    Fernández-Rhodes, Lindsay; Hodonsky, Chani J; Graff, Mariaelisa; Love, Shelly-Ann M; Howard, Annie Green; Seyerle, Amanda A; Avery, Christy L; Chittoor, Geetha; Franceschini, Nora; Voruganti, V Saroja; Young, Kristin; O'Connell, Jeffrey R; North, Kari E; Justice, Anne E

    2016-01-01

    Nearly half of adults in the United States who are diagnosed with hypertension use blood-pressure-lowering medications. Yet there is a large interindividual variability in the response to these medications. Two complementary gene-environment interaction methods have been published and incorporated into publicly available software packages to examine interaction effects, including whether genetic variants modify the association between medication use and blood pressure. The first approach uses a gene-environment interaction term to measure the change in outcome when both the genetic marker and medication are present (the "interaction model"). The second approach tests for effect-size differences between strata of an environmental exposure (the "med-diff" approach). However, no studies have quantitatively compared how these methods perform with respect to 1 or 2 degree of freedom (DF) tests or in family-based data sets. We evaluated these 2 approaches using simulated genotype-medication response interactions at 3 single nucleotide polymorphisms (SNPs) across a range of minor allele frequencies (MAFs 0.1-5.4 %) using the Genetic Analysis Workshop 19 family sample. The estimated interaction effect sizes were on average larger in the interaction model approach compared to the med-diff approach. The true positive proportion was higher for the med-diff approach for SNPs less than 1 % MAF, but higher for the interaction model when common variants were evaluated (MAF >5 %). The interaction model produced lower false-positive proportions than expected (5 %) across a range of MAFs for both the 1DF and 2DF tests. In contrast, the med-diff approach produced higher but stable false-positive proportions around 5 % across MAFs for both tests. Although the 1DF tests both performed similarly for common variants, the interaction model estimated true interaction effects with less bias and higher true positive proportions than the med-diff approach. However, if rare variation (MAF

  4. Comparison of Cluster, Slab, and Analytic Potential Models for the Dimethyl Methylphosphonate (DMMP)/TiO2 (110) Intermolecular Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Li; Tunega, Daniel; Xu, Lai; Govind, Niranjan; Sun, Rui; Taylor, Ramona; Lischka, Hans; De Jong, Wibe A.; Hase, William L.

    2013-08-29

    In a previous study (J. Phys. Chem. C 2011, 115, 12403) cluster models for the TiO2 rutile (110) surface and MP2 calculations were used to develop an analytic potential energy function for dimethyl methylphosphonate (DMMP) interacting with this surface. In the work presented here, this analytic potential and MP2 cluster models are compared with DFT "slab" calculations for DMMP interacting with the TiO2 (110) surface and with DFT cluster models for the TiO2 (110) surface. The DFT slab calculations were performed with the PW91 and PBE functionals. The analytic potential gives DMMP/ TiO2 (110) potential energy curves in excellent agreement with those obtained from the slab calculations. The cluster models for the TiO2 (110) surface, used for the MP2 calculations, were extended to DFT calculations with the B3LYP, PW91, and PBE functional. These DFT calculations do not give DMMP/TiO2 (110) interaction energies which agree with those from the DFT slab calculations. Analyses of the wave functions for these cluster models show that they do not accurately represent the HOMO and LUMO for the surface, which should be 2p and 3d orbitals, respectively, and the models also do not give an accurate band gap. The MP2 cluster models do not accurately represent the LUMO and that they give accurate DMMP/TiO2 (110) interaction energies is apparently fortuitous, arising from their highly inaccurate band gaps. Accurate cluster models, consisting of 7, 10, and 15 Ti-atoms and which have the correct HOMO and LUMO properties, are proposed. The work presented here illustrates the care that must be taken in "constructing" cluster models which accurately model surfaces.

  5. CCF model comparison

    Energy Technology Data Exchange (ETDEWEB)

    Pulkkinen, U. [VTT Industrial Systems (Finland)

    2004-04-01

    The report describes a simple comparison of two CCF-models, the ECLM, and the Beta-model. The objective of the comparison is to identify differences in the results of the models by applying the models in some simple test data cases. The comparison focuses mainly on theoretical aspects of the above mentioned CCF-models. The properties of the model parameter estimates in the data cases is also discussed. The practical aspects in using and estimating CCFmodels in real PSA context (e.g. the data interpretation, properties of computer tools, the model documentation) are not discussed in the report. Similarly, the qualitative CCF-analyses needed in using the models are not discussed in the report. (au)

  6. Comparison of the Molecular Interaction Volume Model with the Unified Interaction Parameter Formalism in the Fe-Cr-Ni Liquid Alloys at 1873 K

    Institute of Scientific and Technical Information of China (English)

    Dongping TAO

    2006-01-01

    The molecular interaction volume model (MIVM) for a general ternary system was deduced in detail for further clarifying and understanding its general multicomponent expression. Both MIVM and the unified interaction parameterformalism (UIPF) can be used to predict the activities of solutes and solvents in the Fe-Cr-Ni liquid alloys. But the former employs only the infinite dilute activity coefficients, and the later is not applicable without the dilute binary and ternary interaction parameters. MIVM has a certain physical meaning from the viewpoint of statistical thermodynamics, so it is an alternative for the estimation of activity coefficients of the solutes and solvents in a dilute or finite concentration metal solution where the interaction parameters are absent or their accuracies are questionable.

  7. Fluid structure interaction simulation in three-layered aortic aneurysm model under pulsatile flow: comparison of wrapping and stenting.

    Science.gov (United States)

    Gao, Feng; Ueda, Hiroshi; Gang, Li; Okada, Hiroshi

    2013-04-26

    One treatment method for aortic aneurysm is the invasive insertion of a stent into the aneurysm. Another method is wrapping the aneurysm using newly developed expanded polytetrafluoroethylene (PTFE) material. A virtual stented aneurysm model and a wrapped aneurysm model were created to study the flow and wall dynamics by means of fluid-structure interaction analyses. The flow velocity and pressure distribution as well as the deformation and wall stress were investigated. Stenting significantly changed the blood flow pattern and the vortexes in the aneurysm. Wrapping increased the thickness of the aneurysm wall and increased the strength of the vessel wall. The maximum von Mises stress in the stented model was found to be 220,494 Pa and 228,218 Pa at the time of peak flow and peak pressure, respectively. This was reduced by 37.8% and 36.7% to 137,200 and 144,354 Pa, respectively, in the wrapped model. Our results provide information that may improve the understanding of the biomechanics of stenting and wrapping.

  8. Modelling land surface - atmosphere interactions

    DEFF Research Database (Denmark)

    Rasmussen, Søren Højmark

    related to inaccurate land surface modelling, e.g. enhanced warm bias in warm dry summer months. Coupling the regional climate model to a hydrological model shows the potential of improving the surface flux simulations in dry periods and the 2 m air temperature in general. In the dry periods......The study is investigates modelling of land surface – atmosphere interactions in context of fully coupled climatehydrological model. With a special focus of under what condition a fully coupled model system is needed. Regional climate model inter-comparison projects as ENSEMBLES have shown bias...... representation of groundwater in the hydrological model is found to important and this imply resolving the small river valleys. Because, the important shallow groundwater is found in the river valleys. If the model does not represent the shallow groundwater then the area mean surface flux calculation...

  9. Model Checking Feature Interactions

    DEFF Research Database (Denmark)

    Le Guilly, Thibaut; Olsen, Petur; Pedersen, Thomas;

    2015-01-01

    This paper presents an offline approach to analyzing feature interactions in embedded systems. The approach consists of a systematic process to gather the necessary information about system components and their models. The model is first specified in terms of predicates, before being refined to t...... to timed automata. The consistency of the model is verified at different development stages, and the correct linkage between the predicates and their semantic model is checked. The approach is illustrated on a use case from home automation....

  10. Interaction English Teaching Model

    Institute of Scientific and Technical Information of China (English)

    穆宇娜

    2013-01-01

      Malash—Thomas pointed out“Interaction is a process in which people and things act upon each other through their ac⁃tions.”According to different subjects, interaction can be divided into human-computer interaction, people-people interaction and learner-content interaction. According to different forms, interactions can be divided into one-one interaction, one-more interac⁃tion and more-more interaction.“Interaction Education”means that teachers are leading parts and students are the center of class. During teaching process, teachers must lead students to discover. Demands from students can encourage teachers to inspire con⁃versely.Thus it can form a close communication between teachers and students. Teaching and learning are realized in a happy and harmonious atmosphere. Successful English teaching must take new bilateral teaching as the first part, which should let the func⁃tion of the two most important elements develop fully. Teachers should grasp opportunities to guide. Teaching methods need to be flexible, and contents of teaching need to be vivid;students should be keen to think, to participate actively, and can break the tradi⁃tion to produce fresh ideas, and in that situation the capability of students can develop fully. The educational model refers to the simplified description of detailed teaching activities. Possessing dual functions of theory and practice, the educational model is the manifestation of theoretical teaching method. The combination of interaction and educational model which are mentioned above form the“interactive teaching”model. With the coming of economic globalization and integration of science and technology, now communications are increasing with each passing day. If you want to take part in or to get in touch with others, you must use lan⁃guage. English has been learnt for 10 years in Middle school and in college, but it can’t be spoken very fluently. That is a realistic picture as the result of an

  11. The 〈 ln A 〉 study with the Muon tracking detector in the KASCADE-Grande experiment – comparison of hadronic interaction models

    Directory of Open Access Journals (Sweden)

    Łuczak P.

    2015-01-01

    Full Text Available With the KASCADE-Grande Muon Tracking Detector it was possible to measure with high accuracy directions of EAS muons with energy above 0.8 GeV and up to 700 m distance from the shower centre. Reconstructed muon tracks allow investigation of muon pseudorapidity (η distributions. These distributions are nearly identical to the pseudorapidity distributions of their parent mesons produced in hadronic interactions. Comparison of the η distributions from measured and simulated showers can be used to test the quality of the high energy hadronic interaction models. The pseudorapidity distributions reflect the longitudinal development of EAS and, as such, are sensitive to the mass of the cosmic ray primary particles. With various parameters of the η distribution, obtained from the Muon Tracking Detector data, it is possible to calculate the average logarithm of mass of the primary cosmic ray particles. The results of the 〈 ln A 〉 analysis in the primary energy range 1016 eV–1017 eV with the 1st quartile and the mean value of the distributions will be presented for the QGSJet-II-2, QGSJet-II-4, EPOS 1.99 and EPOS LHC models in combination with the FLUKA model.

  12. Paired Comparisons-based Interactive Differential Evolution

    CERN Document Server

    Takagi, Hideyuki

    2009-01-01

    We propose Interactive Differential Evolution (IDE) based on paired comparisons for reducing user fatigue and evaluate its convergence speed in comparison with Interactive Genetic Algorithms (IGA) and tournament IGA. User interface and convergence performance are two big keys for reducing Interactive Evolutionary Computation (IEC) user fatigue. Unlike IGA and conventional IDE, users of the proposed IDE and tournament IGA do not need to compare whole individuals each other but compare pairs of individuals, which largely decreases user fatigue. In this paper, we design a pseudo-IEC user and evaluate another factor, IEC convergence performance, using IEC simulators and show that our proposed IDE converges significantly faster than IGA and tournament IGA, i.e. our proposed one is superior to others from both user interface and convergence performance points of view.

  13. What ice can teach us about water interactions: a critical comparison of the performance of different water models.

    Science.gov (United States)

    Vega, C; Abascal, J L F; Conde, M M; Aragones, J L

    2009-01-01

    The performance of several popular water models (TIP3P, TIP4P, TIP5P and TIP4P/2005) is analyzed. For that purpose the predictions for ten different properties of water are investigated, namely: 1. vapour-liquid equilibria (VLE) and critical temperature; 2. surface tension; 3. densities of the different solid structures of water (ices); 4. phase diagram; 5. melting-point properties; 6. maximum in the density of water at room pressure and thermal coefficients alpha and KT; 7. structure of liquid water and ice; 8. equation of state at high pressures; 9. self-diffusion coefficient; 10. dielectric constant. For each property, the performance of each model is analyzed in detail with a critical discussion of the possible reason of the success or failure of the model. A final judgement on the quality of these models is provided. TIP4P/2005 provides the best description of almost all properties of the list, the only exception being the dielectric constant. In second position, TIP5P and TIP4P yield a similar performance overall, and the last place with the poorest description of the water properties is provided by TIP3P. The ideas leading to the proposal and design of the TIP4P/2005 are also discussed in detail. TIP4P/2005 is probably close to the best description of water that can be achieved with a non-polarizable model described by a single Lennard-Jones (LJ) site and three charges.

  14. Ensemble urban flood simulation in comparison with laboratory-scale experiments: Impact of interaction models for manhole, sewer pipe, and surface flow

    Science.gov (United States)

    Noh, Seong Jin; Lee, Seungsoo; An, Hyunuk; Kawaike, Kenji; Nakagawa, Hajime

    2016-11-01

    An urban flood is an integrated phenomenon that is affected by various uncertainty sources such as input forcing, model parameters, complex geometry, and exchanges of flow among different domains in surfaces and subsurfaces. Despite considerable advances in urban flood modeling techniques, limited knowledge is currently available with regard to the impact of dynamic interaction among different flow domains on urban floods. In this paper, an ensemble method for urban flood modeling is presented to consider the parameter uncertainty of interaction models among a manhole, a sewer pipe, and surface flow. Laboratory-scale experiments on urban flood and inundation are performed under various flow conditions to investigate the parameter uncertainty of interaction models. The results show that ensemble simulation using interaction models based on weir and orifice formulas reproduces experimental data with high accuracy and detects the identifiability of model parameters. Among interaction-related parameters, the parameters of the sewer-manhole interaction show lower uncertainty than those of the sewer-surface interaction. Experimental data obtained under unsteady-state conditions are more informative than those obtained under steady-state conditions to assess the parameter uncertainty of interaction models. Although the optimal parameters vary according to the flow conditions, the difference is marginal. Simulation results also confirm the capability of the interaction models and the potential of the ensemble-based approaches to facilitate urban flood simulation.

  15. Systematic comparison of barriers for heavy-ion fusion calculated on the basis of the double-folding model by employing two versions of nucleon-nucleon interaction

    Science.gov (United States)

    Gontchar, I. I.; Chushnyakova, M. V.

    2016-07-01

    A systematic calculation of barriers for heavy-ion fusion was performed on the basis of the double-folding model by employing two versions of an effective nucleon-nucleon interaction: M3Y interaction and Migdal interaction. The results of calculations by the Hartree-Fockmethod with the SKX coefficients were taken for nuclear densities. The calculations reveal that the fusion barrier is higher in the case of employing theMigdal interaction than in the case of employing the M3Y interaction. In view of this, the use of the Migdal interaction in describing heavy-ion fusion is questionable.

  16. Ridge Regression for Interactive Models.

    Science.gov (United States)

    Tate, Richard L.

    1988-01-01

    An exploratory study of the value of ridge regression for interactive models is reported. Assuming that the linear terms in a simple interactive model are centered to eliminate non-essential multicollinearity, a variety of common models, representing both ordinal and disordinal interactions, are shown to have "orientations" that are favorable to…

  17. Comparison of two electro-hydrodynamic force models for the interaction between helium jet flow and an atmospheric-pressure "plasma jet"

    Science.gov (United States)

    Logothetis, D.; Papadopoulos, P. K.; Svarnas, P.; Vafeas, P.

    2016-12-01

    In this work, two simple phenomenological models of the electro-hydrodynamic force that arises in an atmospheric-pressure "plasma jet" are presented. The models are distinguished by the different boundary conditions applied for the consideration of the plasma propagation length. The comparison is based on numerical simulations, which are combined with experimental data, in order to determine the magnitude of the electro-hydrodynamic force and assess the ability of the two models to evaluate the visible plasma length. The results reveal that the gas flow characteristics depend on the spatial range of the force action and the force magnitude, and vice versa.

  18. Comparison of the Molecular Interaction Volume Model with the Wagner Formulae in the Zn-Pb-In and Zn-Sn-Cd-Pb Dilute Solutions

    Institute of Scientific and Technical Information of China (English)

    Dongping TAO; Zhuo CHEN; Dunfang LI; Yifeng GAO; Qianghua SHEN

    2004-01-01

    The coordination numbers in the molecular interaction volume model (MIVM) can be calculated from the common physical quantities of pure liquid metals. A notable feature of the model lie in its capability to predict the thermodynamic properties of solutes in the Zn-Pb-ln and Zn-Sn-Cd-Pb dilute solutions using only the binary infinite dilute activity coefficients, and the predicted values are in good agreement with the experimental data of the dilute solutions.

  19. Numerical Investigation of Velocity Flow Field inside an Impeller Air Model of a Centrifugal Pump with Vaned Diffuser Interactions and Comparison with PIV Measurements

    Directory of Open Access Journals (Sweden)

    Abdelmadjid Atif

    2010-01-01

    Full Text Available The paper refers to the analysis of interactions between the impeller and the vaned diffuser on the air model of a radial flow pump. The study deals with a numerical simulation of the flow for a full 360° entire impeller and diffuser. The task is carried out close to design operating conditions and for one particular position of the impeller blade with respect to diffuser frame. Among all the results, it has been decided to mainly focus on the flow pattern at the exit part inside the impeller coming from the diffuser vanes interactions. The results are compared to the available PIV measurements.

  20. Electron transfer mechanism and the locality of the system-bath interaction: a comparison of local, semilocal, and pure dephasing models.

    Science.gov (United States)

    Weiss, Emily A; Katz, Gil; Goldsmith, Randall H; Wasielewski, Michael R; Ratner, Mark A; Kosloff, Ronnie; Nitzan, Abraham

    2006-02-21

    We simulate the effects of two types of dephasing processes, a nonlocal dephasing of system eigenstates and a dephasing of semilocal eigenstates, on the rate and mechanism of electron transfer (eT) through a series of donor-bridge-acceptor systems, D-B(N)-A, where N is the number of identical bridge units. Our analytical and numerical results show that pure dephasing, defined as the perturbation of system eigenstates through the system-bath interaction, does not disrupt coherent eT because it induces no localization; electron transfer may proceed through superexchange in a system undergoing only pure dephasing. A more physically reasonable description may be obtained via a system-bath interaction that reflects the perturbation of more local electronic structure by local nuclear distortions and dipole interactions. The degree of locality of this interaction is guided by the structure of the system Hamiltonian and by the nature of the measurement performed on the system (i.e., the nature of the environment). We compare our result from this "semilocal" model with an even more local phenomenological dephasing model. We calculate electron transfer rate by obtaining nonequilibrium steady-state solutions for the elements of a reduced density matrix; a semigroup formalism is used to write down the dissipative part of the equation of motion.

  1. Soliton interactions of integrable models

    Energy Technology Data Exchange (ETDEWEB)

    Ruan Hangyu E-mail: hyruan@mail.nbip.net; Chen Yixin

    2003-08-01

    The solution of integrable (n+1)-dimensional KdV system in bilinear form yields a dromion solution that is localized in all directions. The interactions between two dromions are studied both in analytical and in numerical for three (n+1)-dimensional KdV-type equations (n=1, 2, 3). The same interactive properties between two dromions (solitons) are revealed for these models. The interactions between two dromions (solitons) may be elastic or inelastic for different form of solutions.

  2. Soliton interactions of integrable models

    CERN Document Server

    Ruan Hang Yu

    2003-01-01

    The solution of integrable (n+1)-dimensional KdV system in bilinear form yields a dromion solution that is localized in all directions. The interactions between two dromions are studied both in analytical and in numerical for three (n+1)-dimensional KdV-type equations (n=1, 2, 3). The same interactive properties between two dromions (solitons) are revealed for these models. The interactions between two dromions (solitons) may be elastic or inelastic for different form of solutions.

  3. Comparison of the interactions of daunorubicin in a free form and attached to single-walled carbon nanotubes with model lipid membranes

    Directory of Open Access Journals (Sweden)

    Dorota Matyszewska

    2016-04-01

    Full Text Available In this work the interactions of an anticancer drug daunorubicin (DNR with model thiolipid layers composed of 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (DPPTE were investigated using Langmuir technique. The results obtained for a free drug were compared with the results recorded for DNR attached to SWCNTs as potential drug carrier. Langmuir studies of mixed DPPTE–SWCNTs-DNR monolayers showed that even at the highest investigated content of the nanotubes in the monolayer, the changes in the properties of DPPTE model membranes were not as significant as in case of the incorporation of a free drug, which resulted in a significant increase in the area per molecule and fluidization of the thiolipid layer. The presence of SWCNTs-DNR in the DPPTE monolayer at the air–water interface did not change the organization of the lipid molecules to such extent as the free drug, which may be explained by different types of interactions playing crucial role in these two types of systems. In the case of the interactions of free DNR the electrostatic attraction between positively charged drug and negatively charged DPPTE monolayer play the most important role, while in the case of SWCNTs-DNR adducts the hydrophobic interactions between nanotubes and acyl chains of the lipid seem to be prevailing. Electrochemical studies performed for supported model membranes containing the drug delivered in the two investigated forms revealed that the surface concentration of the drug-nanotube adduct in supported monolayers is comparable to the reported surface concentration of the free DNR incorporated into DPPTE monolayers on gold electrodes. Therefore, it may be concluded that the application of carbon nanotubes as potential DNR carrier allows for the incorporation of comparable amount of the drug into model membranes with simultaneous decrease in the negative changes in the membrane structure and organization, which is an important aspect in terms of side effects of

  4. Interacting Dark Energy Models -- Scalar Linear Perturbations

    CERN Document Server

    Perico, E L D

    2016-01-01

    We extend the dark sector interacting models assuming the dark energy as the sum of independent contributions $\\rho_{\\Lambda} =\\sum_i\\rho_{\\Lambda i}$, associated with (and interacting with) each of the $i$ material species. We derive the linear scalar perturbations for two interacting dark energy scenarios, modeling its cosmic evolution and identifying their different imprints in the CMB and matter power spectrum. Our treatment was carried out for two phenomenological motivated expressions of the dark energy density, $\\rho_\\Lambda(H^2)$ and $\\rho_\\Lambda(R)$. The $\\rho_\\Lambda(H^2)$ description turned out to be a full interacting model, i.e., the dark energy interacts with everyone material species in the universe, whereas the $\\rho_\\Lambda(R)$ description only leads to interactions between dark energy and the non-relativistic matter components; which produces different imprints of the two models on the matter power spectrum. A comparison with the Planck 2015 data was made in order to constrain the free para...

  5. A comparison between Joint Regression Analysis and the Additive Main and Multiplicative Interaction model: the robustness with increasing amounts of missing data

    Directory of Open Access Journals (Sweden)

    Paulo Canas Rodrigues

    2011-12-01

    Full Text Available This paper joins the main properties of joint regression analysis (JRA, a model based on the Finlay-Wilkinson regression to analyse multi-environment trials, and of the additive main effects and multiplicative interaction (AMMI model. The study compares JRA and AMMI with particular focus on robustness with increasing amounts of randomly selected missing data. The application is made using a data set from a breeding program of durum wheat (Triticum turgidum L., Durum Group conducted in Portugal. The results of the two models result in similar dominant cultivars (JRA and winner of mega-environments (AMMI for the same environments. However, JRA had more stable results with the increase in the incidence rates of missing values.

  6. MCNPX Model/Table Comparison

    Energy Technology Data Exchange (ETDEWEB)

    J.S. Hendricks

    2003-03-03

    MCNPX is a Monte Carlo N-Particle radiation transport code extending the capabilities of MCNP4C. As with MCNP, MCNPX uses nuclear data tables to transport neutrons, photons, and electrons. Unlike MCNP, MCNPX also uses (1) nuclear data tables to transport protons; (2) physics models to transport 30 additional particle types (deuterons, tritons, alphas, pions, muons, etc.); and (3) physics models to transport neutrons and protons when no tabular data are available or when the data are above the energy range (20 to 150 MeV) where the data tables end. MCNPX can mix and match data tables and physics models throughout a problem. For example, MCNPX can model neutron transport in a bismuth germinate (BGO) particle detector by using data tables for bismuth and oxygen and using physics models for germanium. Also, MCNPX can model neutron transport in UO{sub 2}, making the best use of physics models and data tables: below 20 MeV, data tables are used; above 150 MeV, physics models are used; between 20 and 150 MeV, data tables are used for oxygen and models are used for uranium. The mix-and-match capability became available with MCNPX2.5.b (November 2002). For the first time, we present here comparisons that calculate radiation transport in materials with various combinations of data charts and model physics. The physics models are poor at low energies (<150 MeV); thus, data tables should be used when available. Our comparisons demonstrate the importance of the mix-and-match capability and indicate how well physics models work in the absence of data tables.

  7. Interactive Dimensioning of Parametric Models

    KAUST Repository

    Kelly, T.

    2015-05-01

    We propose a solution for the dimensioning of parametric and procedural models. Dimensioning has long been a staple of technical drawings, and we present the first solution for interactive dimensioning: A dimension line positioning system that adapts to the view direction, given behavioral properties. After proposing a set of design principles for interactive dimensioning, we describe our solution consisting of the following major components. First, we describe how an author can specify the desired interactive behavior of a dimension line. Second, we propose a novel algorithm to place dimension lines at interactive speeds. Third, we introduce multiple extensions, including chained dimension lines, controls for different parameter types (e.g. discrete choices, angles), and the use of dimension lines for interactive editing. Our results show the use of dimension lines in an interactive parametric modeling environment for architectural, botanical, and mechanical models. © 2015 The Author(s) Computer Graphics Forum © 2015 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd.

  8. The Role of the Kuroshio in the Winter North Pacific Ocean-Atmosphere Interaction: Comparison of a Coupled Model and Observations

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A comparative study between the output of the Flexible Global Climate Model Version 1.0 (FGCM-1.0) and the observations is performed. At 500 hPa, the geopotential height of FGCM is similar to the observations, but in the North Pacific the model gives lower values, and the differences are most significant over the northern boundary of the Pacific. In a net heat flux comparison, the spatial patterns of the two are similar in winter, but more heat loss appears to the east of Japan in FGCM than in COADS. On the interannual timescale, strong (weak) Kuroshio transports to the east of Taiwan lead the increasing (decreasing) net heat flux, which is centered over the Kuroshio Extension region, by 1-2 months, with low (high) pressure anomaly responses appearing at 500 hPa over the North Pacific (north of 25°N) in winter.The northward heat transport of the Kuroshio is one of the important heat sources to support the warming of the atmosphere by the ocean and the formation of the low pressure anomaly at 500 hPa over the North Pacific in winter.

  9. Interactive modeling of storm impact

    Science.gov (United States)

    van Rooijen, A.; Baart, F.; Roelvink, J. A.; Donchyts, G.; Scheel, F.; de Boer, W.

    2014-12-01

    In the past decades the impact of storms on the coastal zone has increasingly drawn the attention of policy makers and coastal planners, engineers and researchers. The mean reason for this interest is the high density of the world's population living near the ocean, in combination with climate change. Due to sea level rise and extremer weather conditions, many of the world's coastlines are becoming more vulnerable to the potential of flooding. Currently it is common practice to predict storm impact using physics-based numerical models. The numerical model utilizes several inputs (e.g. bathymetry, waves, surge) to calculate the impact on the coastline. Traditionally, the numerical modeller takes the following three steps: schematization/model setup, running and post-processing. This process generally has a total feedback time in the order of hours to days, and is suitable for so-called confirmatory modelling.However, often models are applied as an exploratory tool, in which the effect of e.g. different hydraulic conditions, or measures is investigated. The above described traditional work flow is not the most efficient method for exploratory modelling. Interactive modelling lets users adjust a simulation while running. For models typically used for storm impact studies (e.g. XBeach, Delft3D, D-Flow FM), the user can for instance change the storm surge level, wave conditions, or add a measure such as a nourishment or a seawall. The model will take the adjustments into account immediately, and will directly compute the effect. Using this method, tools can be developed in which stakeholders (e.g. coastal planners, policy makers) are in control and together evaluate ideas by interacting with the model. Here we will show initial results for interactive modelling with a storm impact model.

  10. Small-angle fragmentation of carbon ions at 0.6 GeV/n: a comparison with models of ion-ion interactions

    Directory of Open Access Journals (Sweden)

    Krutenkova A.P.

    2015-01-01

    Full Text Available Momentum distributions of hydrogen and helium isotopes from 12C fragmentation at 3.5° were measured at 0.6 GeV/nucleon in the FRAGM experiment at ITEP TWA heavy ion accelerator. The fragments were selected by correlated time of flight and dE/dx measurements with a magnetic spectrometer with scintillation counters. The main attention was drawn to the high momentum region where the fragment velocity exceeds the velocity of the projectile nucleus. The momentum spectra of fragments span the region of the fragmentation peak as well as the cumulative region. The differential cross sections cover six orders of magnitude. The distributions measured are compared to the predictions of three ion-ion interaction models: BC, QMD and LAQGSM03.03. The kinetic energy spectra of fragments in the projectile rest frame have an exponential shape with two temperatures, being defined by their slope parameters.

  11. Interactive graphics for geometry modeling

    Science.gov (United States)

    Wozny, M. J.

    1984-01-01

    An interactive vector capability to create geometry and a raster color shaded rendering capability to sample and verify interim geometric design steps through color snapshots is described. The development is outlined of the underlying methodology which facilitates computer aided engineering and design. At present, raster systems cannot match the interactivity and line-drawing capability of refresh vector systems. Consequently, an intermediate step in mechanical design is used to create objects interactively on the vector display and then scan convert the wireframe model to render it as a color shaded object on a raster display. Several algorithms are presented for rendering such objects. Superquadric solid primitive extend the class of primitives normally used in solid modelers.

  12. [Comparison of four drug interaction screening programs].

    Science.gov (United States)

    Ing Lorenzini, K; Reutemann, B; Samer, C F; Guignard, B; Bonnabry, P; Dayer, P; Perrier, A; Desmeules, J

    2012-10-17

    Adverse drug events (ADE) are a major public health issue, with drug-drug interactions (DDI) being one of well-recognized causes of ADE that could be preventable by the use of DDI screening software. We compared the ability of four programs to detect clinically important DDI. We tested 62 drug pairs with and 12 drug pairs without clinically important DDI. Lexi-Interact and Epocrates were the most sensitive (95%) compared to the Compendium and Theriaque (80 and 73%, respectively). The Compendium and Theriaque also showed the lowest negative predictive value. All programs showed high specificity and positive predictive value. The qualitative assessment showed the best performances for Compendium and Lexi-Interact. The last one seems to be the best screening program, but the Compendium is in French and is freely available.

  13. Model Checking Interactive Markov Chains

    NARCIS (Netherlands)

    Neuhausser, M.; Zhang, Lijun; Esparza, J.; Majumdar, R.

    2010-01-01

    Hermanns has introduced interactive Markov chains (IMCs) which arise as an orthogonal extension of labelled transition systems and continuous-time Markov chains (CTMCs). IMCs enjoy nice compositional aggregation properties which help to minimize the state space incrementally. However, the model chec

  14. Modeling Interactions in Small Groups

    Science.gov (United States)

    Heise, David R.

    2013-01-01

    A new theory of interaction within small groups posits that group members initiate actions when tension mounts between the affective meanings of their situational identities and impressions produced by recent events. Actors choose partners and behaviors so as to reduce the tensions. A computer model based on this theory, incorporating reciprocal…

  15. Anisotropic exchange-interaction model: From the Potts model to the exchange-interaction model

    Science.gov (United States)

    King, T. C.; Chen, H. H.

    1995-04-01

    A spin model called the anisotropic exchange-interaction model is proposed. The Potts model, the exchange-interaction model, and the spin-1/2 anisotropic Heisenberg model are special cases of the proposed model. Thermodynamic properties of the model on the bcc and the fcc lattices are determined by the constant-coupling approximation.

  16. Comparison of particle-wall interaction boundary conditions in the prediction of cyclone collection efficiency in computational fluid dynamics (CFD) modeling

    Energy Technology Data Exchange (ETDEWEB)

    Valverde Ramirez, M.; Coury, J.R.; Goncalves, J.A.S., E-mail: jasgon@ufscar.br [Universidade Federal de Sao Carlos (UFSCar), Sao Carlos, SP (Brazil). Departamento de Engenharia Quimica

    2009-07-01

    In recent years, many computational fluid dynamics (CFD) studies have appeared attempting to predict cyclone pressure drop and collection efficiency. While these studies have been able to predict pressure drop well, they have been only moderately successful in predicting collection efficiency. Part of the reason for this failure has been attributed to the relatively simple wall boundary conditions implemented in the commercially available CFD software, which are not capable of accurately describing the complex particle-wall interaction present in a cyclone. According, researches have proposed a number of different boundary conditions in order to improve the model performance. This work implemented the critical velocity boundary condition through a user defined function (UDF) in the Fluent software and compared its predictions both with experimental data and with the predictions obtained when using Fluent's built-in boundary conditions. Experimental data was obtained from eight laboratory scale cyclones with varying geometric ratios. The CFD simulations were made using the software Fluent 6.3.26. (author)

  17. Comparison between Input Hypothesis and Interaction Hypothesis

    Institute of Scientific and Technical Information of China (English)

    李佳

    2012-01-01

      Krashen’s Input hypothesis and Long’s Interaction hypothesis are both valuable research results in the field of language acquisition and play a significant role in language teaching and learning instruction. Through comparing them, their similarities lie in same goal and basis, same focus on comprehension and same challenge the traditional teaching concept. While the differences lie in Different ways to make exposure comprehensible and different roles that learners play. It is meaningful to make the compari⁃son because the results can be valuable guidance and highlights for language teachers and learners to teach or acquire a new lan⁃guage more efficiently.

  18. Exercise self-identity: interactions with social comparison and exercise behaviour

    NARCIS (Netherlands)

    Verkooijen, K.T.; de Bruijn, G.J.

    2013-01-01

    Possible interactions among exercise self-identity, social comparison and exercise behaviour were explored in a sample of 417 undergraduate students (Mean age = 21.5, SD = 3.0; 73% female). Two models were examined using self-report data; (1) a mediation model which proposed an association between s

  19. Exercise self-identity: interactions with social comparison and exercise behaviour

    NARCIS (Netherlands)

    Verkooijen, K.T.; de Bruijn, G.J.

    2013-01-01

    Possible interactions among exercise self-identity, social comparison and exercise behaviour were explored in a sample of 417 undergraduate students (Mean age = 21.5, SD = 3.0; 73% female). Two models were examined using self-report data; (1) a mediation model which proposed an association between

  20. Exercise self-identity: interactions with social comparison and exercise behaviour

    NARCIS (Netherlands)

    Verkooijen, K.T.; Bruijn, de G.J.

    2013-01-01

    Possible interactions among exercise self-identity, social comparison and exercise behaviour were explored in a sample of 417 undergraduate students (Mean age¿=¿21.5, SD¿=¿3.0; 73% female). Two models were examined using self-report data; (1) a mediation model which proposed an association between

  1. Comparison between Input Hypothesis and Interaction Hypothesis

    Institute of Scientific and Technical Information of China (English)

    宗琦

    2016-01-01

    Second Language Acquisition has received more and more attention since 1950s when it becomes an autonomous field of research. Linguists have carried out many theoretical and empirical studies with a sharp purpose to promote Second Language Acquisition. Krashen’s Input Hypothesis and Long’s Interaction Hypothesis are most influential ones among the studies. They both play important roles in language teaching and learning. The paper will present an account of the two great theories, includ-ing the main claims, theoretical foundations as well as some related empirical works and try to investigate commons and differ-ences between them, based on literature and empirical studies. The purpose of writing this paper is to provide a clear outline of the two theories and point out how they are interrelated yet separate predictions about how second language are learned. It is meaningful because the results can be valuable guidance and highlights for language teachers and learners to teach or acquire a language better.

  2. Modelling hadronic interactions in cosmic ray Monte Carlo generators

    Directory of Open Access Journals (Sweden)

    Pierog Tanguy

    2015-01-01

    Full Text Available Currently the uncertainty in the prediction of shower observables for different primary particles and energies is dominated by differences between hadronic interaction models. The LHC data on minimum bias measurements can be used to test Monte Carlo generators and these new constraints will help to reduce the uncertainties in air shower predictions. In this article, after a short introduction on air showers and Monte Carlo generators, we will show the results of the comparison between the updated version of high energy hadronic interaction models EPOS LHC and QGSJETII-04 with LHC data. Results for air shower simulations and their consequences on comparisons with air shower data will be discussed.

  3. Specific ion interactions with aromatic rings in aqueous solutions: Comparison of molecular dynamics simulations with a thermodynamic solute partitioning model and Raman spectroscopy

    Science.gov (United States)

    Vincent, Jordan C.; Matt, Sarah M.; Rankin, Blake M.; D'Auria, Raffaella; Freites, J. Alfredo; Ben-Amotz, Dor; Tobias, Douglas J.

    2015-10-01

    Specific ion interactions of KF, and the Na+ salts of SO42-, F-, Cl-, NO3-, I-, and ClO4- with benzene in aqueous solutions were investigated using molecular dynamics simulations and compared with experimental Raman multivariate curve resolution (Raman-MCR) and thermodynamic results. Good agreement is found with the hydration-shell partition coefficients of salts obtained from the thermodynamic analysis and of halogen anions obtained from the Raman-MCR spectra of benzene and pyridine. Larger discrepancies between the simulation and thermodynamic cation partitioning results point to the influence of counter-ion interaction on cation partitioning.

  4. Positive interaction of social comparison and personal responsibility for outcomes.

    Science.gov (United States)

    Grygolec, Jaroslaw; Coricelli, Giorgio; Rustichini, Aldo

    2012-01-01

    We formulate and test a model that allows sharp separation between two different ways in which environment affects evaluation of outcomes, by comparing social vs. private and personal responsibility vs. chance. In the experiment, subjects chose between two lotteries, one low-risk and one high-risk. They could then observe the outcomes. By varying the environment between private (they could observe the outcome of the chosen lottery and the outcome of the lottery they had not chosen) and social (they could observe the outcome of the lottery chosen by another subject) we can differentiate the response and brain activity following the feedback in social and private settings. The evidence suggests that envy and pride are significant motives driving decisions and outcomes evaluation, stronger than private emotions like regret and rejoice, with ventral striatum playing a key role. When we focus on the outcome evaluation stage we demonstrate that BOLD signal in ventral striatum is increasing in the difference between obtained and counterfactual payoffs. For a given difference in payoffs, striatal responses are more pronounced in social than in private environment. Moreover, a positive interaction (complementarity) between social comparison and personal responsibility is reflected in the pattern of activity in the ventral striatum. At decision stage we observe getting ahead of the Joneses effect in ventral striatum with subjective value of risk larger in social than in private environment.

  5. Positive Interaction of Social Comparison and Personal Responsibility for Outcomes

    Directory of Open Access Journals (Sweden)

    Jaroslaw eGrygolec

    2012-02-01

    Full Text Available We formulate and test a model that allows a sharp separation between social versus private and personal responsibility versus chance in the evaluation of outcomes. In the experiment, subjects choose between two lotteries, one low-risk and one high-risk. They could then observe the outcomes. By varying the environment between private (in which they could only observe the outcome of the lottery they had not chosen and social (they could observe the outcome of the lottery chosen by another subject we can differentiate the response and brain activity following the feedback in social and private settings. The evidence suggests that envy and pride are significant motives driving decisions and outcomes evaluation, stronger than private emotions like regret and rejoice, with ventral striatum playing a key role. Focusing on outcomes evaluation stage we demonstrate that BOLD signal in ventral striatum is increasing in the difference between obtained and counterfactual payoffs. For a given difference in payoffs, striatal responses are more pronounced in social than in private environment. Moreover, a positive interaction (complementarity between social comparison and personal responsibility is reflected in the pattern of activity in the ventral striatum. At decision stage we observe getting ahead of the Joneses effect in ventral striatum with subjective value of risk larger in social than in private environment.

  6. Comparison of protein interaction networks reveals species conservation and divergence

    Directory of Open Access Journals (Sweden)

    Teng Maikun

    2006-10-01

    Full Text Available Abstract Background Recent progresses in high-throughput proteomics have provided us with a first chance to characterize protein interaction networks (PINs, but also raised new challenges in interpreting the accumulating data. Results Motivated by the need of analyzing and interpreting the fast-growing data in the field of proteomics, we propose a comparative strategy to carry out global analysis of PINs. We compare two PINs by combining interaction topology and sequence similarity to identify conserved network substructures (CoNSs. Using this approach we perform twenty-one pairwise comparisons among the seven recently available PINs of E.coli, H.pylori, S.cerevisiae, C.elegans, D.melanogaster, M.musculus and H.sapiens. In spite of the incompleteness of data, PIN comparison discloses species conservation at the network level and the identified CoNSs are also functionally conserved and involve in basic cellular functions. We investigate the yeast CoNSs and find that many of them correspond to known complexes. We also find that different species harbor many conserved interaction regions that are topologically identical and these regions can constitute larger interaction regions that are topologically different but similar in framework. Based on the species-to-species difference in CoNSs, we infer potential species divergence. It seems that different species organize orthologs in similar but not necessarily the same topology to achieve similar or the same function. This attributes much to duplication and divergence of genes and their associated interactions. Finally, as the application of CoNSs, we predict 101 protein-protein interactions (PPIs, annotate 339 new protein functions and deduce 170 pairs of orthologs. Conclusion Our result demonstrates that the cross-species comparison strategy we adopt is powerful for the exploration of biological problems from the perspective of networks.

  7. Interactive Modelling of Molecular Structures

    Science.gov (United States)

    Rustad, J. R.; Kreylos, O.; Hamann, B.

    2004-12-01

    The "Nanotech Construction Kit" (NCK) [1] is a new project aimed at improving the understanding of molecular structures at a nanometer-scale level by visualization and interactive manipulation. Our very first prototype is a virtual-reality program allowing the construction of silica and carbon structures from scratch by assembling them one atom at a time. In silica crystals or glasses, the basic building block is an SiO4 unit, with the four oxygen atoms arranged around the central silicon atom in the shape of a regular tetrahedron. Two silicate units can connect to each other by their silicon atoms covalently bonding to one shared oxygen atom. Geometrically, this means that two tetrahedra can link at their vertices. Our program is based on geometric representations and uses simple force fields to simulate the interaction of building blocks, such as forming/breaking of bonds and repulsion. Together with stereoscopic visualization and direct manipulation of building blocks using wands or data gloves, this enables users to create realistic and complex molecular models in short amounts of time. The NCK can either be used as a standalone tool, to analyze or experiment with molecular structures, or it can be used in combination with "traditional" molecular dynamics (MD) simulations. In a first step, the NCK can create initial configurations for subsequent MD simulation. In a more evolved setup, the NCK can serve as a visual front-end for an ongoing MD simulation, visualizing changes in simulation state in real time. Additionally, the NCK can be used to change simulation state on-the-fly, to experiment with different simulation conditions, or force certain events, e.g., the forming of a bond, and observe the simulation's reaction. [1] http://graphics.cs.ucdavis.edu/~okreylos/ResDev/NanoTech

  8. Comparison of biomolecules on the basis of Molecular Interaction Potentials

    Directory of Open Access Journals (Sweden)

    Rodrigo Jordi

    2002-01-01

    Full Text Available Molecular Interaction Potentials (MIP are frequently used for the comparison of series of compounds displaying related biological behaviors. These potentials are interaction energies between the considered compounds and relevant probes. The interaction energies are computed in the nodes of grids defined around the compounds. There is a need of detailed and objective comparative analyses of MIP distributions in the framework of structure-activity studies. On the other hand, MIP-based studies do not have to be restricted to series of small ligands, since such studies present also interesting possibilities for the analysis and comparison of biological macromolecules. Such analyses can benefit from the application of new methods and computational approaches. The new software MIPSim (Molecular Interaction Potentials Similarity analysis has recently been introduced with the purpose of analyzing and comparing MIP distributions of series of biomolecules. This program is transparently integrated with other programs, like GAMESS or GRID, which can be used for the computation of the potentials to be analyzed or compared. MIPSim incorporates several definitions of similarity coefficients, and is capable of combining several similarity measures into a single one. On the other hand, MIPSim can perform automatic explorations of the maximum similarity alignments between pairs of molecules.

  9. A probabilistic algorithm for interactive huge genome comparison.

    Science.gov (United States)

    Courtois, P R; Moncany, M L

    1995-12-01

    We designed a new probabilistic algorithm, named PAGEC (probabilistic algorithm for genome comparison), which allowed a highly interactive study of long genomic strings. The comparison between two nucleic acid sequences is based on the creation of multiple index tables, which drastically reduces processing time for huge genomes, e.g. 13 min for a 4 Mb/4 Mb comparison. PAGEC lowered the need for memory when compared with other types of algorithm and took into account the low resolution of the final representation (paper or computer screen). Considering that standard printers permit a 300 d.p.i. resolution, the loss of computed information due to the probabilistic conception of the algorithm was not usually noticeable in the present study, mainly due to increased genomic sizes. Refinement was possible through an interactive zooming system, which enabled the visualization of the lexical base sequences of a considered part of both of the studied genomes. Biological examples of computation based on yeast and animal nucleic acid sequences presented in this paper reveal the flexibility of the PAGEC program, which is a valuable tool for genetic studies as it offers a solution to an important problem that will become even more important as time passes.

  10. Phenomenological analysis of the interacting boson model

    Science.gov (United States)

    Hatch, R. L.; Levit, S.

    1982-01-01

    The classical Hamiltonian of the interacting boson model is defined and expressed in terms of the conventional quadrupole variables. This is used in the analyses of the dynamics in the various limits of the model. The purpose is to determine the range and the features of the collective phenomena which the interacting boson model is capable of describing. In the commonly used version of the interacting boson model with one type of the s and d bosons and quartic interactions, this capability has certain limitations and the model should be used with care. A more sophisticated version of the interacting boson model with neutron and proton bosons is not discussed. NUCLEAR STRUCTURE Interacting bosons, classical IBM Hamiltonian in quadrupole variables, phenomenological content of the IBM and its limitations.

  11. Comparison of cluster expansion fitting algorithms for interactions at surfaces

    Science.gov (United States)

    Herder, Laura M.; Bray, Jason M.; Schneider, William F.

    2015-10-01

    Cluster expansions (CEs) are Ising-type interaction models that are increasingly used to model interaction and ordering phenomena at surfaces, such as the adsorbate-adsorbate interactions that control coverage-dependent adsorption or surface-vacancy interactions that control surface reconstructions. CEs are typically fit to a limited set of data derived from density functional theory (DFT) calculations. The CE fitting process involves iterative selection of DFT data points to include in a fit set and selection of interaction clusters to include in the CE. Here we compare the performance of three CE fitting algorithms-the MIT Ab-initio Phase Stability code (MAPS, the default in ATAT software), a genetic algorithm (GA), and a steepest descent (SD) algorithm-against synthetic data. The synthetic data is encoded in model Hamiltonians of varying complexity motivated by the observed behavior of atomic adsorbates on a face-centered-cubic transition metal close-packed (111) surface. We compare the performance of the leave-one-out cross-validation score against the true fitting error available from knowledge of the hidden CEs. For these systems, SD achieves lowest overall fitting and prediction error independent of the underlying system complexity. SD also most accurately predicts cluster interaction energies without ignoring or introducing extra interactions into the CE. MAPS achieves good results in fewer iterations, while the GA performs least well for these particular problems.

  12. Species Coexistence in Nitrifying Chemostats: A Model of Microbial Interactions

    Directory of Open Access Journals (Sweden)

    Maxime Dumont

    2016-12-01

    Full Text Available In a previous study, the two nitrifying functions (ammonia oxidizing bacteria (AOB or nitrite-oxidizing bacteria (NOB of a nitrification reactor—operated continuously over 525 days with varying inputs—were assigned using a mathematical modeling approach together with the monitoring of bacterial phylotypes. Based on these theoretical identifications, we develop here a chemostat model that does not explicitly include only the resources’ dynamics (different forms of soluble nitrogen but also explicitly takes into account microbial inter- and intra-species interactions for the four dominant phylotypes detected in the chemostat. A comparison of the models obtained with and without interactions has shown that such interactions permit the coexistence of two competing ammonium-oxidizing bacteria and two competing nitrite-oxidizing bacteria in competition for ammonium and nitrite, respectively. These interactions are analyzed and discussed.

  13. AIC, BIC, Bayesian evidence against the interacting dark energy model

    Science.gov (United States)

    Szydłowski, Marek; Krawiec, Adam; Kurek, Aleksandra; Kamionka, Michał

    2015-01-01

    Recent astronomical observations have indicated that the Universe is in a phase of accelerated expansion. While there are many cosmological models which try to explain this phenomenon, we focus on the interacting CDM model where an interaction between the dark energy and dark matter sectors takes place. This model is compared to its simpler alternative—the CDM model. To choose between these models the likelihood ratio test was applied as well as the model comparison methods (employing Occam's principle): the Akaike information criterion (AIC), the Bayesian information criterion (BIC) and the Bayesian evidence. Using the current astronomical data: type Ia supernova (Union2.1), , baryon acoustic oscillation, the Alcock-Paczynski test, and the cosmic microwave background data, we evaluated both models. The analyses based on the AIC indicated that there is less support for the interacting CDM model when compared to the CDM model, while those based on the BIC indicated that there is strong evidence against it in favor of the CDM model. Given the weak or almost non-existing support for the interacting CDM model and bearing in mind Occam's razor we are inclined to reject this model.

  14. AIC, BIC, Bayesian evidence against the interacting dark energy model

    Energy Technology Data Exchange (ETDEWEB)

    Szydłowski, Marek, E-mail: marek.szydlowski@uj.edu.pl [Astronomical Observatory, Jagiellonian University, Orla 171, 30-244, Kraków (Poland); Mark Kac Complex Systems Research Centre, Jagiellonian University, Reymonta 4, 30-059, Kraków (Poland); Krawiec, Adam, E-mail: adam.krawiec@uj.edu.pl [Institute of Economics, Finance and Management, Jagiellonian University, Łojasiewicza 4, 30-348, Kraków (Poland); Mark Kac Complex Systems Research Centre, Jagiellonian University, Reymonta 4, 30-059, Kraków (Poland); Kurek, Aleksandra, E-mail: alex@oa.uj.edu.pl [Astronomical Observatory, Jagiellonian University, Orla 171, 30-244, Kraków (Poland); Kamionka, Michał, E-mail: kamionka@astro.uni.wroc.pl [Astronomical Institute, University of Wrocław, ul. Kopernika 11, 51-622, Wrocław (Poland)

    2015-01-14

    Recent astronomical observations have indicated that the Universe is in a phase of accelerated expansion. While there are many cosmological models which try to explain this phenomenon, we focus on the interacting ΛCDM model where an interaction between the dark energy and dark matter sectors takes place. This model is compared to its simpler alternative—the ΛCDM model. To choose between these models the likelihood ratio test was applied as well as the model comparison methods (employing Occam’s principle): the Akaike information criterion (AIC), the Bayesian information criterion (BIC) and the Bayesian evidence. Using the current astronomical data: type Ia supernova (Union2.1), h(z), baryon acoustic oscillation, the Alcock–Paczynski test, and the cosmic microwave background data, we evaluated both models. The analyses based on the AIC indicated that there is less support for the interacting ΛCDM model when compared to the ΛCDM model, while those based on the BIC indicated that there is strong evidence against it in favor of the ΛCDM model. Given the weak or almost non-existing support for the interacting ΛCDM model and bearing in mind Occam’s razor we are inclined to reject this model.

  15. AIC, BIC, Bayesian evidence against the interacting dark energy model

    Energy Technology Data Exchange (ETDEWEB)

    Szydlowski, Marek [Jagiellonian University, Astronomical Observatory, Krakow (Poland); Jagiellonian University, Mark Kac Complex Systems Research Centre, Krakow (Poland); Krawiec, Adam [Jagiellonian University, Institute of Economics, Finance and Management, Krakow (Poland); Jagiellonian University, Mark Kac Complex Systems Research Centre, Krakow (Poland); Kurek, Aleksandra [Jagiellonian University, Astronomical Observatory, Krakow (Poland); Kamionka, Michal [University of Wroclaw, Astronomical Institute, Wroclaw (Poland)

    2015-01-01

    Recent astronomical observations have indicated that the Universe is in a phase of accelerated expansion. While there are many cosmological models which try to explain this phenomenon, we focus on the interacting ΛCDM model where an interaction between the dark energy and dark matter sectors takes place. This model is compared to its simpler alternative - the ΛCDM model. To choose between these models the likelihood ratio test was applied as well as the model comparison methods (employing Occam's principle): the Akaike information criterion (AIC), the Bayesian information criterion (BIC) and the Bayesian evidence. Using the current astronomical data: type Ia supernova (Union2.1), h(z), baryon acoustic oscillation, the Alcock- Paczynski test, and the cosmic microwave background data, we evaluated both models. The analyses based on the AIC indicated that there is less support for the interacting ΛCDM model when compared to the ΛCDM model, while those based on the BIC indicated that there is strong evidence against it in favor of the ΛCDM model. Given the weak or almost non-existing support for the interacting ΛCDM model and bearing in mind Occam's razor we are inclined to reject this model. (orig.)

  16. NN Interaction in Chiral Constituent Quark Models

    CERN Document Server

    Valcarce, A; González, P

    2003-01-01

    We review the actual state in the description of the NN interaction by means of chiral constituent quark models. We present a series of relevant features that are nicely explained within the quark model framework.

  17. Semantic models for adaptive interactive systems

    CERN Document Server

    Hussein, Tim; Lukosch, Stephan; Ziegler, Jürgen; Calvary, Gaëlle

    2013-01-01

    Providing insights into methodologies for designing adaptive systems based on semantic data, and introducing semantic models that can be used for building interactive systems, this book showcases many of the applications made possible by the use of semantic models.Ontologies may enhance the functional coverage of an interactive system as well as its visualization and interaction capabilities in various ways. Semantic models can also contribute to bridging gaps; for example, between user models, context-aware interfaces, and model-driven UI generation. There is considerable potential for using

  18. Interactive Water Resources Modeling and Model Use: An Overview

    Science.gov (United States)

    Loucks, Daniel P.; Kindler, Janusz; Fedra, Kurt

    1985-02-01

    This serves as an introduction for the following sequence of five papers on interactive water resources and environmental management, policy modeling, and model use. We review some important shortcomings of many management and policy models and argue for improved human-computer-model interaction and communication. This interaction can lead to more effective model use which in turn should facilitate the exploration, analysis, and synthesis of alternative designs, plans, and policies by those directly involved in the planning, management, or policy making process. Potential advantages of interactive modeling and model use, as well as some problems and research needs, are discussed.

  19. Comparison of cloud models for Brown Dwarfs

    CERN Document Server

    Helling, Ch; Allard, F; Dehn, M; Hauschildt, P; Homeier, D; Lodders, K; Marley, M; Rietmeijer, F; Tsuji, T; Woitke, P

    2007-01-01

    A test case comparison is presented for different dust cloud model approaches applied in brown dwarfs and giant gas planets. We aim to achieve more transparency in evaluating the uncertainty inherent to theoretical modelling. We show in how far model results for characteristic dust quantities vary due to different assumptions. We also demonstrate differences in the spectral energy distributions resulting from our individual cloud modelling in 1D substellar atmosphere simulations

  20. String Interactions in c=1 Matrix Model

    CERN Document Server

    De Boer, J; Verlinde, E; Yee, J T; Boer, Jan de; Sinkovics, Annamaria; Verlinde, Erik; Yee, Jung-Tay

    2004-01-01

    We study string interactions in the fermionic formulation of the c=1 matrix model. We give a precise nonperturbative description of the rolling tachyon state in the matrix model, and discuss S-matrix elements of the c=1 string. As a first step to study string interactions, we compute the interaction of two decaying D0-branes in terms of free fermions. This computation is compared with the string theory cylinder diagram using the rolling tachyon ZZ boundary states.

  1. MCNPX Model/Table Comparison

    CERN Document Server

    Hendricks, J S

    2003-01-01

    MCNPX is a Monte Carlo N-Particle radiation transport code extending the capabilities of MCNP4C. As with MCNP, MCNPX uses nuclear data tables to transport neutrons, photons, and electrons. Unlike MCNP, MCNPX also uses (1) nuclear data tables to transport protons; (2) physics models to transport 30 additional particle types (deuterons, tritons, alphas, pions, muons, etc.); and (3) physics models to transport neutrons and protons when no tabular data are available or when the data are above the energy range (20 to 150 MeV) where the data tables end. MCNPX can mix and match data tables and physics models throughout a problem. For example, MCNPX can model neutron transport in a bismuth germinate (BGO) particle detector by using data tables for bismuth and oxygen and using physics models for germanium. Also, MCNPX can model neutron transport in UO sub 2 , making the best use of physics models and data tables: below 20 MeV, data tables are used; above 150 MeV, physics models are used; between 20 and 150 MeV, data t...

  2. Fragmentary model of exchange interactions

    CERN Document Server

    Kotov, V M

    2000-01-01

    This article makes attempt to refusal from using neutrino for explanation continuous distribution of beta particle energy by conversion to characteristic exchange interaction particles in nucleolus. It is taking formulation for nuclear position with many different fragments. It is computing half-value period of spontaneous fission of heavy nucleolus. (author)

  3. Modeling graphene-substrate interactions

    NARCIS (Netherlands)

    Amlaki, T.

    2016-01-01

    In this thesis I focussed on the interactions between graphene-like materials (grapheme and germanene) and various substrates. The attractive properties of graphene like a high carrier mobility, its single-atomic thickness and its theoretical magic have made graphene a very popular and promising can

  4. Modeling graphene-substrate interactions

    NARCIS (Netherlands)

    Amlaki, Taher

    2016-01-01

    In this thesis I focussed on the interactions between graphene-like materials (grapheme and germanene) and various substrates. The attractive properties of graphene like a high carrier mobility, its single-atomic thickness and its theoretical magic have made graphene a very popular and promising can

  5. Comparison between observations and model

    OpenAIRE

    Claußnitzer, Antje

    2010-01-01

    In recent years the development of numerical weather prediction models has shown great progress in the short-term and medium-range forecast of temperature, wind speed or direction and cloud coverage, but only little success in the quantitative precipitation forecast. Rainfall is one of the most difficult forecasting meteorological variable. To improve the numerical models, it is necessary to understand the rainfall processes. This thesis contributes towards an understanding since the precipit...

  6. Modeling of soil-water-structure interaction

    DEFF Research Database (Denmark)

    Tang, Tian

    to dynamic ocean waves. The goal of this research project is to develop numerical soil models for computing realistic seabed response in the interacting offshore environment, where ocean waves, seabed and offshore structure highly interact with each other. The seabed soil models developed are based...... as the developed nonlinear soil displacements and stresses under monotonic and cyclic loading. With the FVM nonlinear coupled soil models as a basis, multiphysics modeling of wave-seabed-structure interaction is carried out. The computations are done in an open source code environment, OpenFOAM, where FVM models...... of Computational Fluid Dynamics (CFD) and structural mechanics are available. The interaction in the system is modeled in a 1-way manner: First detailed free surface CFD calculations are executed to obtain a realistic wave field around a given structure. Then the dynamic structural response, due to the motions...

  7. Spatial interactions in agent-based modeling

    CERN Document Server

    Ausloos, Marcel; Merlone, Ugo

    2014-01-01

    Agent Based Modeling (ABM) has become a widespread approach to model complex interactions. In this chapter after briefly summarizing some features of ABM the different approaches in modeling spatial interactions are discussed. It is stressed that agents can interact either indirectly through a shared environment and/or directly with each other. In such an approach, higher-order variables such as commodity prices, population dynamics or even institutions, are not exogenously specified but instead are seen as the results of interactions. It is highlighted in the chapter that the understanding of patterns emerging from such spatial interaction between agents is a key problem as much as their description through analytical or simulation means. The chapter reviews different approaches for modeling agents' behavior, taking into account either explicit spatial (lattice based) structures or networks. Some emphasis is placed on recent ABM as applied to the description of the dynamics of the geographical distribution o...

  8. An Interactive Whiteboard Model Survey: Reliable Development

    Directory of Open Access Journals (Sweden)

    Bih-Yaw Shih

    2012-04-01

    Full Text Available Applications and practices of interactive whiteboards (IWBs in school learning is important focus and development trend for developmented countries in recent years. There are rare researches and discussions about IWB teaching materials for course teaching and teaching effectiveness. As for the aspect of academic studies, there is more practical teaching sharing for subjects such as language learning, mathematical learning and physical science learning; however, it is rarely seen empirical research on the application of IWB for educational acceptances of interactive whiteboards. Based on its imporatances, we summarize previous literatures to establish a theoretical model for interactive whiteboards (IWBs. Variables in this model are then discussed to find out the interaction between each other. The contribution of the study develops an innovative model for educational acceptances of interactive whiteboards using hybrid TAM, ECM, and Flow models.

  9. Are all Linear Paired Comparison Models Equivalent

    Science.gov (United States)

    1990-09-01

    Previous authors (Jackson and Fleckenstein 1957, Mosteller 1958, Noether 1960) have found that different models of paired comparisons data lead to simi...ponential distribution with a location parameter (Mosteller 1958, Noether 1960). Formal statements describing the limiting behavior of the gamma...that are not convolu- tion type linear models (the uniform model considered by Smith (1956), Mosteller (1958), Noether (1960)) and other convolution

  10. Comparison of Frictional Heating Models

    Energy Technology Data Exchange (ETDEWEB)

    Davies, Nicholas R [ORNL; Blau, Peter Julian [ORNL

    2013-10-01

    The purpose of this work was to compare the predicted temperature rises using four well-known models for frictional heating under a few selected conditions in which similar variable inputs are provided to each model. Classic papers by Archard, Kuhlmann-Wilsdorf, Lim and Ashby, and Rabinowicz have been examined, and a spreadsheet (Excel ) was developed to facilitate the calculations. This report may be used in conjunction with that spreadsheet. It explains the background, assumptions, and rationale used for the calculations. Calculated flash temperatures for selected material combinations, under a range of applied loads and sliding speeds, are tabulated. The materials include AISI 52100 bearing steel, CDA 932 bronze, NBD 200 silicon nitride, Ti-6Al-4V alloy, and carbon-graphite material. Due to the assumptions made by the different models, and the direct way in which certain assumed quantities, like heat sink distances or asperity dimensions, enter into the calculations, frictional hearing results may differ significantly; however, they can be similar in certain cases in light of certain assumptions that are shared between the models.

  11. A Computational Model for Rotor-Fuselage Interactional Aerodynamics

    Science.gov (United States)

    Boyd, D. Douglas, Jr.; Barnwell, Richard W.; Gorton, Susan Althoff

    2000-01-01

    A novel unsteady rotor-fuselage interactional aerodynamics model has been developed. This model loosely couples a Generalized Dynamic Wake Theory (GDWT) to a thin-layer Navier-Stokes solution procedure. This coupling is achieved using an unsteady pressure jump boundary condition in the Navier-Stokes model. The new unsteady pressure jump boundary condition models each rotor blade as a moving pressure jump which travels around the rotor azimuth and is applied between two adjacent planes in a cylindrical, non-rotating grid. Comparisons are made between measured and predicted time-averaged and time-accurate rotor inflow ratios. Additional comparisons are made between measured and predicted unsteady surface pressures on the top centerline and sides of the fuselage.

  12. Bayesian Model comparison of Higgs couplings

    CERN Document Server

    Bergstrom, Johannes

    2014-01-01

    We investigate the possibility of contributions from physics beyond the Standard Model (SM) to the Higgs couplings, in the light of the LHC data. The work is performed within an interim framework where the magnitude of the Higgs production and decay rates are rescaled though Higgs coupling scale factors. We perform Bayesian parameter inference on these scale factors, concluding that there is good compatibility with the SM. Furthermore, we carry out Bayesian model comparison on all models where any combination of scale factors can differ from their SM values and find that typically models with fewer free couplings are strongly favoured. We consider the evidence that each coupling individually equals the SM value, making the minimal assumptions on the other couplings. Finally, we make a comparison of the SM against a single "not-SM" model, and find that there is moderate to strong evidence for the SM.

  13. A Method for Model Checking Feature Interactions

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Le Guilly, Thibaut; Ravn, Anders Peter;

    2015-01-01

    This paper presents a method to check for feature interactions in a system assembled from independently developed concurrent processes as found in many reactive systems. The method combines and refines existing definitions and adds a set of activities. The activities describe how to populate the ...... the definitions with models to ensure that all interactions are captured. The method is illustrated on a home automation example with model checking as analysis tool. In particular, the modelling formalism is timed automata and the analysis uses UPPAAL to find interactions....

  14. Dynamical Models of Dyadic Interactions with Delay

    CERN Document Server

    Bielczyk, Natalia; Płatkowski, Tadeusz

    2012-01-01

    When interpersonal interactions between individuals are described by the (discrete or continuous) dynamical systems, the interactions are usually assumed to be instantaneous: the rates of change of the actual states of the actors at given instant of time are assumed to depend on their states at the same time. In reality the natural time delay should be included in the corresponding models. We investigate a general class of linear models of dyadic interactions with a constant discrete time delay. We prove that in such models the changes of stability of the stationary points from instability to stability or vice versa occur for various intervals of the parameters which determine the intensity of interactions. The conditions guaranteeing arbitrary number (zero, one ore more) of switches are formulated and the relevant theorems are proved. A systematic analysis of all generic cases is carried out. It is obvious that the dynamics of interactions depend both on the strength of reactions of partners on their own sta...

  15. Galaxy Zoo: Mergers - Dynamical models of interacting galaxies

    Science.gov (United States)

    Holincheck, Anthony J.; Wallin, John F.; Borne, Kirk; Fortson, Lucy; Lintott, Chris; Smith, Arfon M.; Bamford, Steven; Keel, William C.; Parrish, Michael

    2016-06-01

    The dynamical history of most merging galaxies is not well understood. Correlations between galaxy interaction and star formation have been found in previous studies, but require the context of the physical history of merging systems for full insight into the processes that lead to enhanced star formation. We present the results of simulations that reconstruct the orbit trajectories and disturbed morphologies of pairs of interacting galaxies. With the use of a restricted three-body simulation code and the help of citizen scientists, we sample 105 points in parameter space for each system. We demonstrate a successful recreation of the morphologies of 62 pairs of interacting galaxies through the review of more than 3 million simulations. We examine the level of convergence and uniqueness of the dynamical properties of each system. These simulations represent the largest collection of models of interacting galaxies to date, providing a valuable resource for the investigation of mergers. This paper presents the simulation parameters generated by the project. They are now publicly available in electronic format at http://data.galaxyzoo.org/mergers.html. Though our best-fitting model parameters are not an exact match to previously published models, our method for determining uncertainty measurements will aid future comparisons between models. The dynamical clocks from our models agree with previous results of the time since the onset of star formation from starburst models in interacting systems and suggest that tidally induced star formation is triggered very soon after closest approach.

  16. Matrix models with Penner interaction inspired by interacting ribonucleic acid

    Indian Academy of Sciences (India)

    Pradeep Bhadola; N Deo

    2015-02-01

    The Penner interaction known in studies of moduli space of punctured Riemann surfaces is introduced and studied in the context of random matrix model of homo RNA. An analytic derivation of the generating function is given and the corresponding partition function is derived numerically. An additional dependence of the structure combinatorics factor on (related to the size of the matrix and the interaction strength) is obtained. This factor has a strong effect on the structure combinatorics in the low regime. Databases are scanned for real ribonucleic acid (RNA) structures and pairing information for these RNA structures is computationally extracted. Then the genus is calculated for every structure and plotted as a function of length. The genus distribution function is compared with the prediction from the nonlinear (NL) model. The specific heat and distribution of structure with temperature calculated from the NL model shows that the NL inter-action is biased towards planar structures. The second derivative of specific heat changes phase from a double peaked function for small to a single peak for large . Detailed analysis reveals the presence of the double peak only for genus 0 structures, the higher genii behave normally with . Comparable behaviour is found in studies involving interactions of RNA with osmolytes and monovalent cations in unfolding experiments.

  17. Using Interaction Scenarios to Model Information Systems

    DEFF Research Database (Denmark)

    Bækgaard, Lars; Bøgh Andersen, Peter

    The purpose of this paper is to define and discuss a set of interaction primitives that can be used to model the dynamics of socio-technical activity systems, including information systems, in a way that emphasizes structural aspects of the interaction that occurs in such systems. The primitives...

  18. Hydraulic fracture model comparison study: Complete results

    Energy Technology Data Exchange (ETDEWEB)

    Warpinski, N.R. [Sandia National Labs., Albuquerque, NM (United States); Abou-Sayed, I.S. [Mobil Exploration and Production Services (United States); Moschovidis, Z. [Amoco Production Co. (US); Parker, C. [CONOCO (US)

    1993-02-01

    Large quantities of natural gas exist in low permeability reservoirs throughout the US. Characteristics of these reservoirs, however, make production difficult and often economic and stimulation is required. Because of the diversity of application, hydraulic fracture design models must be able to account for widely varying rock properties, reservoir properties, in situ stresses, fracturing fluids, and proppant loads. As a result, fracture simulation has emerged as a highly complex endeavor that must be able to describe many different physical processes. The objective of this study was to develop a comparative study of hydraulic-fracture simulators in order to provide stimulation engineers with the necessary information to make rational decisions on the type of models most suited for their needs. This report compares the fracture modeling results of twelve different simulators, some of them run in different modes for eight separate design cases. Comparisons of length, width, height, net pressure, maximum width at the wellbore, average width at the wellbore, and average width in the fracture have been made, both for the final geometry and as a function of time. For the models in this study, differences in fracture length, height and width are often greater than a factor of two. In addition, several comparisons of the same model with different options show a large variability in model output depending upon the options chosen. Two comparisons were made of the same model run by different companies; in both cases the agreement was good. 41 refs., 54 figs., 83 tabs.

  19. A Comparison of Different Machine Transliteration Models

    CERN Document Server

    Choi, K; Oh, J; 10.1613/jair.1999

    2011-01-01

    Machine transliteration is a method for automatically converting words in one language into phonetically equivalent ones in another language. Machine transliteration plays an important role in natural language applications such as information retrieval and machine translation, especially for handling proper nouns and technical terms. Four machine transliteration models -- grapheme-based transliteration model, phoneme-based transliteration model, hybrid transliteration model, and correspondence-based transliteration model -- have been proposed by several researchers. To date, however, there has been little research on a framework in which multiple transliteration models can operate simultaneously. Furthermore, there has been no comparison of the four models within the same framework and using the same data. We addressed these problems by 1) modeling the four models within the same framework, 2) comparing them under the same conditions, and 3) developing a way to improve machine transliteration through this com...

  20. Comparison of Present SST Gravity Field Models

    Institute of Scientific and Technical Information of China (English)

    LUO Jia; SHI Chuang; ZOU Xiancai; WANG Haihong

    2006-01-01

    Taking the main land of Europe as the region to be studied, the potential of the new satellite gravity technique: satellite-to-satellite tracking (SST) and improving the accuracy of regional gravity field model with the SST models are investigated. The drawbacks of these models are discussed. With GPM98C as the reference, the gravity anomaly residuals of several other models, the latest SST global gravity field models (EIGEN series and GGM series), were computed and compared. The results of the comparison show that in the selected region, some systematic errors with periodical properties exist in the EIGEN and GGM's S series models in the high degree and order. Some information that was not shown in the classic gravity models is detected in the low and middle degree and order of EIGEN and GGM's S series models. At last, the effective maximum degrees and orders of SST models are suggested.

  1. Information Retrieval Interaction: an Analysis of Models

    Directory of Open Access Journals (Sweden)

    Farahnaz Sadoughi

    2012-03-01

    Full Text Available Information searching process is an interactive process; thus users has control on searching process, and they can manage the results of the search process. In this process, user's question became more mature, according to retrieved results. In addition, on the side of the information retrieval system, there are some processes that could not be realized, unless by user. Practically, this issue, is egregious in “Interaction” -i.e. process of user connection to other system elements- and in “Relevance judgment”. This paper had a glance to existence of “Interaction” in information retrieval, in first. Then the tradition model of information retrieval and its strenght and weak points were reviewed. Finally, the current models of interactive information retrieval includes: Belkin episodic model, Ingwersen cognitive model, Sarasevic stratified model, and Spinks interactive feedback model were elucidated.

  2. Syndetic model of fundamental interactions

    Directory of Open Access Journals (Sweden)

    Ernest Ma

    2015-02-01

    Full Text Available The standard model of quarks and leptons is extended to connect three outstanding issues in particle physics and astrophysics: (1 the absence of strong CP nonconservation, (2 the existence of dark matter, and (3 the mechanism of nonzero neutrino masses, and that of the first family of quarks and leptons, all in the context of having only one Higgs boson in a renormalizable theory. Some phenomenological implications are discussed.

  3. Advances in modeling of biomolecular interactions

    Institute of Scientific and Technical Information of China (English)

    Cong-zhongCAI; Ze-rongLI; Wan-luWANG; Yu-zongCHEN

    2004-01-01

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

  4. A Heuristic Molecular Model of Hydrophobic Interactions

    OpenAIRE

    Hummer, G; Garde, S; Garcia, A.E.; Pohorille, A; Pratt, L.R.

    1995-01-01

    Hydrophobic interactions provide driving forces for protein folding, membrane formation, and oil-water separation. Motivated by information theory, the poorly understood nonpolar solute interactions in water are investigated. A simple heuristic model of hydrophobic effects in terms of density fluctuations is developed. This model accounts quantitatively for the central hydrophobic phenomena of cavity formation and association of inert gas solutes; it therefore clarifies the underlying physics...

  5. Convergent series for lattice models with polynomial interactions

    Science.gov (United States)

    Ivanov, Aleksandr S.; Sazonov, Vasily K.

    2017-01-01

    The standard perturbative weak-coupling expansions in lattice models are asymptotic. The reason for this is hidden in the incorrect interchange of the summation and integration. However, substituting the Gaussian initial approximation of the perturbative expansions by a certain interacting model or regularizing original lattice integrals, one can construct desired convergent series. In this paper we develop methods, which are based on the joint and separate utilization of the regularization and new initial approximation. We prove, that the convergent series exist and can be expressed as re-summed standard perturbation theory for any model on the finite lattice with the polynomial interaction of even degree. We discuss properties of such series and study their applicability to practical computations on the example of the lattice ϕ4-model. We calculate expectation value using the convergent series, the comparison of the results with the Borel re-summation and Monte Carlo simulations shows a good agreement between all these methods.

  6. Convergent series for lattice models with polynomial interactions

    CERN Document Server

    Ivanov, Aleksandr S

    2016-01-01

    The standard perturbative weak-coupling expansions in lattice models are asymptotic. The reason for this is hidden in the incorrect interchange of the summation and integration. However, substituting the Gaussian initial approximation of the perturbative expansions by a certain interacting model or regularizing original lattice integrals, one can construct desired convergent series. In this paper we develop methods, which are based on the joint and separate utilization of the regularization and new initial approximation. We prove, that the convergent series exist and can be expressed as the re-summed standard perturbation theory for any model on the finite lattice with the polynomial interaction of even degree. We discuss properties of such series and make them applicable to practical computations. The workability of the methods is demonstrated on the example of the lattice $\\phi^4$-model. We calculate the operator $\\langle\\phi_n^2\\rangle$ using the convergent series, the comparison of the results with the Bo...

  7. Mathematical models for plant-herbivore interactions

    Science.gov (United States)

    Feng, Zhilan; DeAngelis, Donald L.

    2017-01-01

    Mathematical Models of Plant-Herbivore Interactions addresses mathematical models in the study of practical questions in ecology, particularly factors that affect herbivory, including plant defense, herbivore natural enemies, and adaptive herbivory, as well as the effects of these on plant community dynamics. The result of extensive research on the use of mathematical modeling to investigate the effects of plant defenses on plant-herbivore dynamics, this book describes a toxin-determined functional response model (TDFRM) that helps explains field observations of these interactions. This book is intended for graduate students and researchers interested in mathematical biology and ecology.

  8. Modeling of Laser Material Interactions

    Science.gov (United States)

    Garrison, Barbara

    2009-03-01

    Irradiation of a substrate by laser light initiates the complex chemical and physical process of ablation where large amounts of material are removed. Ablation has been successfully used in techniques such as nanolithography and LASIK surgery, however a fundamental understanding of the process is necessary in order to further optimize and develop applications. To accurately describe the ablation phenomenon, a model must take into account the multitude of events which occur when a laser irradiates a target including electronic excitation, bond cleavage, desorption of small molecules, ongoing chemical reactions, propagation of stress waves, and bulk ejection of material. A coarse grained molecular dynamics (MD) protocol with an embedded Monte Carlo (MC) scheme has been developed which effectively addresses each of these events during the simulation. Using the simulation technique, thermal and chemical excitation channels are separately studied with a model polymethyl methacrylate system. The effects of the irradiation parameters and reaction pathways on the process dynamics are investigated. The mechanism of ablation for thermal processes is governed by a critical number of bond breaks following the deposition of energy. For the case where an absorbed photon directly causes a bond scission, ablation occurs following the rapid chemical decomposition of material. The study provides insight into the influence of thermal and chemical processes in polymethyl methacrylate and facilitates greater understanding of the complex nature of polymer ablation.

  9. Electroweak and Strong Interactions Phenomenology, Concepts, Models

    CERN Document Server

    Scheck, Florian

    2012-01-01

    Electroweak and Strong Interaction: Phenomenology, Concepts, Models, begins with relativistic quantum mechanics and some quantum field theory which lay the foundation for the rest of the text. The phenomenology and the physics of the fundamental interactions are emphasized through a detailed discussion of the empirical fundamentals of unified theories of strong, electromagnetic, and weak interactions. The principles of local gauge theories are described both in a heuristic and a geometric framework. The minimal standard model of the fundamental interactions is developed in detail and characteristic applications are worked out. Possible signals of physics beyond that model, notably in the physics of neutrinos are also discussed. Among the applications scattering on nucleons and on nuclei provide salient examples. Numerous exercises with solutions make the text suitable for advanced courses or individual study. This completely updated revised new edition contains an enlarged chapter on quantum chromodynamics an...

  10. Software Testing Method Based on Model Comparison

    Institute of Scientific and Technical Information of China (English)

    XIE Xiao-dong; LU Yan-sheng; MAO Cheng-yin

    2008-01-01

    A model comparison based software testing method (MCST) is proposed. In this method, the requirements and programs of software under test are transformed into the ones in the same form, and described by the same model describe language (MDL).Then, the requirements are transformed into a specification model and the programs into an implementation model. Thus, the elements and structures of the two models are compared, and the differences between them are obtained. Based on the diffrences, a test suite is generated. Different MDLs can be chosen for the software under test. The usages of two classical MDLs in MCST, the equivalence classes model and the extended finite state machine (EFSM) model, are described with example applications. The results show that the test suites generated by MCST are more efficient and smaller than some other testing methods, such as the path-coverage testing method, the object state diagram testing method, etc.

  11. Learning models of activities involving interacting objects

    DEFF Research Database (Denmark)

    Manfredotti, Cristina; Pedersen, Kim Steenstrup; Hamilton, Howard J.;

    2013-01-01

    We propose the LEMAIO multi-layer framework, which makes use of hierarchical abstraction to learn models for activities involving multiple interacting objects from time sequences of data concerning the individual objects. Experiments in the sea navigation domain yielded learned models that were...

  12. Modeling of hydrogen interactions with beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Longhurst, G.R. [Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States)

    1998-01-01

    In this paper, improved mathematical models are developed for hydrogen interactions with beryllium. This includes the saturation effect observed for high-flux implantation of ions from plasmas and retention of tritium produced from neutronic transmutations in beryllium. Use of the models developed is justified by showing how they can replicated experimental data using the TMAP4 tritium transport code. (author)

  13. Learning models of activities involving interacting objects

    DEFF Research Database (Denmark)

    Manfredotti, Cristina; Pedersen, Kim Steenstrup; Hamilton, Howard J.

    2013-01-01

    We propose the LEMAIO multi-layer framework, which makes use of hierarchical abstraction to learn models for activities involving multiple interacting objects from time sequences of data concerning the individual objects. Experiments in the sea navigation domain yielded learned models that were t...

  14. Multisite Interactions in Lattice-Gas Models

    Science.gov (United States)

    Einstein, T. L.; Sathiyanarayanan, R.

    For detailed applications of lattice-gas models to surface systems, multisite interactions often play at least as significant a role as interactions between pairs of adatoms that are separated by a few lattice spacings. We recall that trio (3-adatom, non-pairwise) interactions do not inevitably create phase boundary asymmetries about half coverage. We discuss a sophisticated application to an experimental system and describe refinements in extracting lattice-gas energies from calculations of total energies of several different ordered overlayers. We describe how lateral relaxations complicate matters when there is direct interaction between the adatoms, an issue that is important when examining the angular dependence of step line tensions. We discuss the connector model as an alternative viewpoint and close with a brief account of recent work on organic molecule overlayers.

  15. Modelling earthquake interaction and seismicity statistics

    Science.gov (United States)

    Steacy, S.; Hetherington, A.

    2009-04-01

    The effects of earthquake interaction and fault complexity on seismicity statistics are investigated in a 3D model composed of a number of cellular automata (each representing an individual fault) distributed in a volume. Each automaton is assigned a fractal distribution of strength. Failure occurs when the 3D Coulomb stress on any cell exceeds its strength and stress transfer during simulated earthquake rupture is via nearest-neighbor rules formulated to give realistic stress concentrations. An event continues until all neighboring cells whose stresses exceed their strengths have ruptured and the size of the event is determined from its area and stress drop. Long-range stress interactions are computed following the termination of simulated ruptures using a boundary element code. In practice, these stress perturbations are only computed for events above a certain size (e.g. a threshold length of 10 km) and stresses are updated on nearby structures. Events which occur as a result of these stress interactions are considered to be "triggered" earthquakes and they, in turn, can trigger further seismic activity. The threshold length for computing interaction stresses is a free parameter and hence interaction can be "turned off" by setting this to an unrealistically high value. We consider 3 synthetic fault networks of increasing degrees of complexity - modelled on the North Anatolian fault system, the structures in the San Francisco Bay Area, and the Southern California fault network. We find that the effect of interaction is dramatically different in networks of differing complexity. In the North Anatolian analogue, for example, interaction leads to a decreased number of events, increased b-values, and an increase in recurrence intervals. In the Bay Area model, by contrast, we observe that interaction increases the number of events, decreases the b-values, and has little effect on recurrence intervals. For all networks, we find that interaction can activate mis

  16. Learning models of activities involving interacting objects

    DEFF Research Database (Denmark)

    Manfredotti, Cristina; Pedersen, Kim Steenstrup; Hamilton, Howard J.;

    2013-01-01

    We propose the LEMAIO multi-layer framework, which makes use of hierarchical abstraction to learn models for activities involving multiple interacting objects from time sequences of data concerning the individual objects. Experiments in the sea navigation domain yielded learned models that were...... then successfully applied to activity recognition, activity simulation and multi-target tracking. Our method compares favourably with respect to previously reported results using Hidden Markov Models and Relational Particle Filtering....

  17. SOFTWARE RELIABILITY MODEL FOR COMPONENT INTERACTION MODE

    Institute of Scientific and Technical Information of China (English)

    Wang Qiang; Lu Yang; Xu Zijun; Han Jianghong

    2011-01-01

    With the rapid progress of component technology,the software development methodology of gathering a large number of components for designing complex software systems has matured.But,how to assess the application reliability accurately with the information of system architecture and the components reliabilities together has become a knotty problem.In this paper,the defects in formal description of software architecture and the limitations in existed model assumptions are both analyzed.Moreover,a new software reliability model called Component Interaction Mode (CIM) is proposed.With this model,the problem for existed component-based software reliability analysis models that cannot deal with the cases of component interaction with non-failure independent and non-random control transition is resolved.At last,the practice examples are presented to illustrate the effectiveness of this model

  18. A Heuristic Molecular Model of Hydrophobic Interactions

    CERN Document Server

    Hummer, G; García, A E; Pohorille, A; Pratt, L R

    1995-01-01

    Hydrophobic interactions provide driving forces for protein folding, membrane formation, and oil-water separation. Motivated by information theory, the poorly understood nonpolar solute interactions in water are investigated. A simple heuristic model of hydrophobic effects in terms of density fluctuations is developed. This model accounts quantitatively for the central hydrophobic phenomena of cavity formation and association of inert gas solutes; it therefore clarifies the underlying physics of hydrophobic effects and permits important applications to conformational equilibria of nonpolar solutes and hydrophobic residues in biopolymers.

  19. The standard model of electroweak interactions

    CERN Document Server

    Pich, Antonio

    1994-01-01

    What follows is an updated version of the lectures given at the CERN Academic Training (November 1993) and at the Jaca Winter Meeting (February 1994). The aim is to provide a pedagogical introduction to the Standard Model of electroweak interactions. After briefly reviewing the empirical considerations which lead to the construction of the Standard Model Lagrangian, the particle content, structure and symmetries of the theory are discussed. Special emphasis is given to the many phenomenological tests (universality, flavour-changing neutral currents, precision measurements, quark mixing, etc.) which have established this theoretical framework as the Standard Theory of electroweak interactions.

  20. MODEL PSEUDOPOTENTIAL OF THE ELECTRON - NEGATIVE ION INTERACTION

    Directory of Open Access Journals (Sweden)

    Yu.Rudavskii

    2003-01-01

    Full Text Available Generalization of the Anderson model to describe the states of electronegative impurities in liquid-metal alloys is the main aim of the present paper. The effects of the random inner field on the charge impurity states is accounted for selfconsistently. Qualitative and quantitative estimation of hamiltonian parameters has been carried out. The limits of the proposed model applicability to a description of real systems are considered. Especially, the case of the oxygen impurity in liquid sodium is studied. The modelling of the proper electron-ionic interaction potential is the main goal of the paper. The parameters of the proposed pseudopotential are analyzed in detail. The comparison with other model potentials have been carried out. Resistivity of liquid sodium containing the oxygen impurities is calculated with utilizing the form-factor of the proposed model potential. Dependence of the resistivity on impurity concentration and on the charge states is received.

  1. Comparison of Transcription Factor Binding Site Models

    KAUST Repository

    Bhuyan, Sharifulislam

    2012-05-01

    Modeling of transcription factor binding sites (TFBSs) and TFBS prediction on genomic sequences are important steps to elucidate transcription regulatory mechanism. Dependency of transcription regulation on a great number of factors such as chemical specificity, molecular structure, genomic and epigenetic characteristics, long distance interaction, makes this a challenging problem. Different experimental procedures generate evidence that DNA-binding domains of transcription factors show considerable DNA sequence specificity. Probabilistic modeling of TFBSs has been moderately successful in identifying patterns from a family of sequences. In this study, we compare performances of different probabilistic models and try to estimate their efficacy over experimental TFBSs data. We build a pipeline to calculate sensitivity and specificity from aligned TFBS sequences for several probabilistic models, such as Markov chains, hidden Markov models, Bayesian networks. Our work, containing relevant statistics and evaluation for the models, can help researchers to choose the most appropriate model for the problem at hand.

  2. GCSS Idealized Cirrus Model Comparison Project

    Science.gov (United States)

    Starr, David OC.; Benedetti, Angela; Boehm, Matt; Brown, Philip R. A.; Gierens, Klaus; Girard, Eric; Giraud, Vincent; Jakob, Christian; Jensen, Eric; Khvorostyanov, Vitaly; hide

    2000-01-01

    The GCSS Working Group on Cirrus Cloud Systems (WG2) is conducting a systematic comparison and evaluation of cirrus cloud models. This fundamental activity seeks to support the improvement of models used for climate simulation and numerical weather prediction through assessment and improvement of the "process" models underlying parametric treatments of cirrus cloud processes in large-scale models. The WG2 Idealized Cirrus Model Comparison Project is an initial comparison of cirrus cloud simulations by a variety of cloud models for a series of idealized situations with relatively simple initial conditions and forcing. The models (16) represent the state-of-the-art and include 3-dimensional large eddy simulation (LES) models, two-dimensional cloud resolving models (CRMs), and single column model (SCM) versions of GCMs. The model microphysical components are similarly varied, ranging from single-moment bulk (relative humidity) schemes to fully size-resolved (bin) treatments where ice crystal growth is explicitly calculated. Radiative processes are included in the physics package of each model. The baseline simulations include "warm" and "cold" cirrus cases where cloud top initially occurs at about -47C and -66C, respectively. All simulations are for nighttime conditions (no solar radiation) where the cloud is generated in an ice supersaturated layer, about 1 km in depth, with an ice pseudoadiabatic thermal stratification (neutral). Continuing cloud formation is forced via an imposed diabatic cooling representing a 3 cm/s uplift over a 4-hour time span followed by a 2-hour dissipation stage with no cooling. Variations of these baseline cases include no-radiation and stable-thermal-stratification cases. Preliminary results indicated the great importance of ice crystal fallout in determining even the gross cloud characteristics, such as average vertically-integrated ice water path (IWP). Significant inter-model differences were found. Ice water fall speed is directly

  3. Global Quantitative Modeling of Chromatin Factor Interactions

    Science.gov (United States)

    Zhou, Jian; Troyanskaya, Olga G.

    2014-01-01

    Chromatin is the driver of gene regulation, yet understanding the molecular interactions underlying chromatin factor combinatorial patterns (or the “chromatin codes”) remains a fundamental challenge in chromatin biology. Here we developed a global modeling framework that leverages chromatin profiling data to produce a systems-level view of the macromolecular complex of chromatin. Our model ultilizes maximum entropy modeling with regularization-based structure learning to statistically dissect dependencies between chromatin factors and produce an accurate probability distribution of chromatin code. Our unsupervised quantitative model, trained on genome-wide chromatin profiles of 73 histone marks and chromatin proteins from modENCODE, enabled making various data-driven inferences about chromatin profiles and interactions. We provided a highly accurate predictor of chromatin factor pairwise interactions validated by known experimental evidence, and for the first time enabled higher-order interaction prediction. Our predictions can thus help guide future experimental studies. The model can also serve as an inference engine for predicting unknown chromatin profiles — we demonstrated that with this approach we can leverage data from well-characterized cell types to help understand less-studied cell type or conditions. PMID:24675896

  4. Modelling hadronic interactions in HEP MC generators

    CERN Document Server

    Skands, Peter

    2015-01-01

    HEP event generators aim to describe high-energy collisions in full exclusive detail. They combine perturbative matrix elements and parton showers with dynamical models of less well-understood phenomena such as hadronization, diffraction, and the so-called underlying event. We briefly summarise some of the main concepts relevant to the modelling of soft/inclusive hadron interactions in MC generators, in particular PYTHIA, with emphasis on questions recently highlighted by LHC data.

  5. A fashion model with social interaction

    Science.gov (United States)

    Nakayama, Shoichiro; Nakamura, Yasuyuki

    2004-06-01

    In general, it is difficult to investigate social phenomena mathematically or quantitatively due to non-linear interactions. Statistical physics can provide powerful methods for studying social phenomena with interactions, and could be very useful for them. In this study, we take a focus on fashion as a social phenomenon with interaction. The social interaction considered here are “bandwagon effect” and “snob effect.” In the bandwagon effect, the correlation between one's behavior and others is positive. People feel fashion weary or boring when it is overly popular. This is the snob effect. It is assumed that the fashion phenomenon is formed by the aggregation of individual's binary choice, that is, the fashion is adopted or not. We formulate the fashion phenomenon as the logit model, which is based on the random utility theory in social science, especially economics. The model derived here basically has the similarity with the pioneering model by Weidlich (Phys. Rep. 204 (1991) 1), which was derived from the master equation, the Langevin equation, or the Fokker-Planck equation. This study seems to give the behavioral or behaviormetrical foundation to his model. As a result of dynamical analysis, it is found that in the case that both the bandwagon effect and the snob effect work, periodic or chaotic behavior of fashion occurs under certain conditions.

  6. Parameter Symmetry of the Interacting Boson Model

    CERN Document Server

    Shirokov, A M; Smirnov, Yu F; Shirokov, Andrey M.; Smirnov, Yu. F.

    1998-01-01

    We discuss the symmetry of the parameter space of the interacting boson model (IBM). It is shown that for any set of the IBM Hamiltonian parameters (with the only exception of the U(5) dynamical symmetry limit) one can always find another set that generates the equivalent spectrum. We discuss the origin of the symmetry and its relevance for physical applications.

  7. A yarn interaction model for circular braiding

    NARCIS (Netherlands)

    Ravenhorst, van J.H.; Akkerman, R.

    2016-01-01

    Machine control data for the automation of the circular braiding process has been generated using previously published mathematical models that neglect yarn interaction. This resulted in a significant deviation from the required braid angle at mandrel cross-sectional changes, likely caused by an inc

  8. Intuitionistic preference modeling and interactive decision making

    CERN Document Server

    Xu, Zeshui

    2014-01-01

    This book offers an in-depth and comprehensive introduction to the priority methods of intuitionistic preference relations, the consistency and consensus improving procedures for intuitionistic preference relations, the approaches to group decision making based on intuitionistic preference relations, the approaches and models for interactive decision making with intuitionistic fuzzy information, and the extended results in interval-valued intuitionistic fuzzy environments.

  9. Statistical pairwise interaction model of stock market

    Science.gov (United States)

    Bury, Thomas

    2013-03-01

    Financial markets are a classical example of complex systems as they are compound by many interacting stocks. As such, we can obtain a surprisingly good description of their structure by making the rough simplification of binary daily returns. Spin glass models have been applied and gave some valuable results but at the price of restrictive assumptions on the market dynamics or they are agent-based models with rules designed in order to recover some empirical behaviors. Here we show that the pairwise model is actually a statistically consistent model with the observed first and second moments of the stocks orientation without making such restrictive assumptions. This is done with an approach only based on empirical data of price returns. Our data analysis of six major indices suggests that the actual interaction structure may be thought as an Ising model on a complex network with interaction strengths scaling as the inverse of the system size. This has potentially important implications since many properties of such a model are already known and some techniques of the spin glass theory can be straightforwardly applied. Typical behaviors, as multiple equilibria or metastable states, different characteristic time scales, spatial patterns, order-disorder, could find an explanation in this picture.

  10. Comparison of Photovoltaic Models in the System Advisor Model: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Blair, N. J.; Dobos, A. P.; Gilman, P.

    2013-08-01

    The System Advisor Model (SAM) is free software developed by the National Renewable Energy Laboratory (NREL) for predicting the performance of renewable energy systems and analyzing the financial feasibility of residential, commercial, and utility-scale grid-connected projects. SAM offers several options for predicting the performance of photovoltaic (PV) systems. The model requires that the analyst choose from three PV system models, and depending on that choice, possibly choose from three module and two inverter component models. To obtain meaningful results from SAM, the analyst must be aware of the differences between the model options and their applicability to different modeling scenarios. This paper presents an overview the different PV model options and presents a comparison of results for a 200-kW system using different model options.

  11. Gravitational Interactions in a General Multibrane Model

    CERN Document Server

    Bloomfield, Jolyon K

    2010-01-01

    The gravitational interactions of the four-dimensional effective theory describing a general N-brane model in five dimensions without radion stabilization are analyzed. The parameter space is constrained by requiring that there be no ghost modes in the theory, and that the Eddington parameterized post-Newtonian parameter gamma be consistent with observations. We show that we must reside on the brane on which the warp factor is maximized. The resultant theory contains N-1 radion modes in a nonlinear sigma model, with the target space being a subset of hyperbolic space. Imposing observational constraints on the relative strengths of gravitational interactions of dark and visible matter shows that at least 99.8% of the dark matter must live on our brane in this model.

  12. Algebraic Turbulence-Chemistry Interaction Model

    Science.gov (United States)

    Norris, Andrew T.

    2012-01-01

    The results of a series of Perfectly Stirred Reactor (PSR) and Partially Stirred Reactor (PaSR) simulations are compared to each other over a wide range of operating conditions. It is found that the PaSR results can be simulated by a PSR solution with just an adjusted chemical reaction rate. A simple expression has been developed that gives the required change in reaction rate for a PSR solution to simulate the PaSR results. This expression is the basis of a simple turbulence-chemistry interaction model. The interaction model that has been developed is intended for use with simple one-step global reaction mechanisms and for steady-state flow simulations. Due to the simplicity of the model there is very little additional computational cost in adding it to existing CFD codes.

  13. Comparison of Spatiotemporal Fusion Models: A Review

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2015-02-01

    Full Text Available Simultaneously capturing spatial and temporal dynamics is always a challenge for the remote sensing community. Spatiotemporal fusion has gained wide interest in various applications for its superiority in integrating both fine spatial resolution and frequent temporal coverage. Though many advances have been made in spatiotemporal fusion model development and applications in the past decade, a unified comparison among existing fusion models is still limited. In this research, we classify the models into three categories: transformation-based, reconstruction-based, and learning-based models. The objective of this study is to (i compare four fusion models (STARFM, ESTARFM, ISTAFM, and SPSTFM under a one Landsat-MODIS (L-M pair prediction mode and two L-M pair prediction mode using time-series datasets from the Coleambally irrigation area and Poyang Lake wetland; (ii quantitatively assess prediction accuracy considering spatiotemporal comparability, landscape heterogeneity, and model parameter selection; and (iii discuss the advantages and disadvantages of the three categories of spatiotemporal fusion models.

  14. Secret neutrino interactions: a pseudoscalar model

    Science.gov (United States)

    Archidiacono, Maria; Hannestad, Steen; Sloth Hansen, Rasmus; Tram, Thomas

    2016-05-01

    Neutrino oscillation experiments point towards the existence of additional mostly sterile neutrino mass eigenstates in the eV mass range. At the same time, such sterile neutrinos are disfavoured by cosmology (Big Bang Nucleosynthesis, Cosmic Microwave Background and Large Scale Structure), unless they can be prevented from being thermalised in the early Universe. To this aim, we introduce a model of sterile neutrino secret interactions mediated by a new light pseudoscalar: The new interactions can accomodate sterile neutrinos in the early Universe, providing a good fit to all the up to date cosmological data.

  15. The Frontier Fields Lens Modeling Comparison Project

    CERN Document Server

    Meneghetti, M; Coe, D; Contini, E; De Lucia, G; Giocoli, C; Acebron, A; Borgani, S; Bradac, M; Diego, J M; Hoag, A; Ishigaki, M; Johnson, T L; Jullo, E; Kawamata, R; Lam, D; Limousin, M; Liesenborgs, J; Oguri, M; Sebesta, K; Sharon, K; Williams, L L R; Zitrin, A

    2016-01-01

    Gravitational lensing by clusters of galaxies offers a powerful probe of their structure and mass distribution. Deriving a lens magnification map for a galaxy cluster is a classic inversion problem and many methods have been developed over the past two decades to solve it. Several research groups have developed techniques independently to map the predominantly dark matter distribution in cluster lenses. While these methods have all provided remarkably high precision mass maps, particularly with exquisite imaging data from the Hubble Space Telescope (HST), the reconstructions themselves have never been directly compared. In this paper, we report the results of comparing various independent lens modeling techniques employed by individual research groups in the community. Here we present for the first time a detailed and robust comparison of methodologies for fidelity, accuracy and precision. For this collaborative exercise, the lens modeling community was provided simulated cluster images -- of two clusters Are...

  16. Model selection and comparison for independents sinusoids

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Christensen, Mads Græsbøll; Jensen, Søren Holdt

    2014-01-01

    this method by considering the problem in a full Bayesian framework instead of the approximate formulation, on which the asymptotic MAP criterion is based. This leads to a new model selection and comparison method, the lp-BIC, whose computational complexity is of the same order as the asymptotic MAP criterion......In the signal processing literature, many methods have been proposed for estimating the number of sinusoidal basis functions from a noisy data set. The most popular method is the asymptotic MAP criterion, which is sometimes also referred to as the BIC. In this paper, we extend and improve....... Through simulations, we demonstrate that the lp-BIC outperforms the asymptotic MAP criterion and other state of the art methods in terms of model selection, de-noising and prediction performance. The simulation code is available online....

  17. Interacting Dark Energy Models and Observations

    Science.gov (United States)

    Shojaei, Hamed; Urioste, Jazmin

    2017-01-01

    Dark energy is one of the mysteries of the twenty first century. Although there are candidates resembling some features of dark energy, there is no single model describing all the properties of dark energy. Dark energy is believed to be the most dominant component of the cosmic inventory, but a lot of models do not consider any interaction between dark energy and other constituents of the cosmic inventory. Introducing an interaction will change the equation governing the behavior of dark energy and matter and creates new ways to explain cosmic coincidence problem. In this work we studied how the Hubble parameter and density parameters evolve with time in the presence of certain types of interaction. The interaction serves as a way to convert dark energy into matter to avoid a dark energy-dominated universe by creating new equilibrium points for the differential equations. Then we will use numerical analysis to predict the values of distance moduli at different redshifts and compare them to the values for the distance moduli obtained by WMAP (Wilkinson Microwave Anisotropy Probe). Undergraduate Student

  18. Comments on interactions in the SUSY models

    CERN Document Server

    Upadhyay, Sudhakar; Mandal, Bhabani Prasad

    2016-01-01

    We consider the special supersymmetry (SUSY) transformations with $m$ generators $\\overleftarrow{s}_\\alpha,$ for some class of the models and study the physical consequences when making the Grassmann-odd transformations to form an Abelian supergroup with finite parameters and set of group-like elements with finite parameters being by a functionals of field variables. The SUSY-invariant path integral measure within conventional quantization scheme leads to appearance of the Jacobian under change of variables generated by such SUSY transformations, which is explicitly calculated. The Jacobian leads, first, to appearance of only trivial interactions in the transformed action, second, to the presence of modified Ward identity, which reduceds to the standard Ward identities for constant parameters. We examine the case of ${N}=1$, $N=2$ supersymmetric harmonic oscillator to illustrate the general concept on a free simple model with $(1,1)$ physical degrees of freedom. It is shown that the interaction terms, $U_{tr}...

  19. Modeling of soil-water-structure interaction

    DEFF Research Database (Denmark)

    Tang, Tian

    The trend towards the installation of more offshore constructions for the production and transmission of marine oil, gas and wind power is expected to continue over the coming years. An important process in the offshore construction design is the assessment of seabed soil stability exposed...... to dynamic ocean waves. The goal of this research project is to develop numerical soil models for computing realistic seabed response in the interacting offshore environment, where ocean waves, seabed and offshore structure highly interact with each other. The seabed soil models developed are based...... on the ’modified’ Biot’s consolidation equations, in which the soil-pore fluid coupling is extended to account for the various nonlinear soil stress-strain relations included. The Finite volume method (FVM) together with a segregated solution strategy has been used to numerically solve the governing equations...

  20. Atomistic modeling of dislocation-interface interactions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian [Los Alamos National Laboratory; Valone, Steven M [Los Alamos National Laboratory; Beyerlein, Irene J [Los Alamos National Laboratory; Misra, Amit [Los Alamos National Laboratory; Germann, T. C. [Los Alamos National Laboratory

    2011-01-31

    Using atomic scale models and interface defect theory, we first classify interface structures into a few types with respect to geometrical factors, then study the interfacial shear response and further simulate the dislocation-interface interactions using molecular dynamics. The results show that the atomic scale structural characteristics of both heterophases and homophases interfaces play a crucial role in (i) their mechanical responses and (ii) the ability of incoming lattice dislocations to transmit across them.

  1. Interacting holographic generalized cosmic Chaplygin gas model

    Science.gov (United States)

    Naji, Jalil

    2014-03-01

    In this paper we consider a correspondence between the holographic dark energy density and interacting generalized cosmic Chaplygin gas energy density in flat FRW universe. Then, we reconstruct the potential of the scalar field which describe the generalized cosmic Chaplygin cosmology. In the special case we obtain time-dependent energy density and study cosmological parameters. We find stability condition of this model which is depend on cosmic parameter.

  2. PRIMO: An Interactive Homology Modeling Pipeline

    Science.gov (United States)

    Glenister, Michael

    2016-01-01

    The development of automated servers to predict the three-dimensional structure of proteins has seen much progress over the years. These servers make calculations simpler, but largely exclude users from the process. In this study, we present the PRotein Interactive MOdeling (PRIMO) pipeline for homology modeling of protein monomers. The pipeline eases the multi-step modeling process, and reduces the workload required by the user, while still allowing engagement from the user during every step. Default parameters are given for each step, which can either be modified or supplemented with additional external input. PRIMO has been designed for users of varying levels of experience with homology modeling. The pipeline incorporates a user-friendly interface that makes it easy to alter parameters used during modeling. During each stage of the modeling process, the site provides suggestions for novice users to improve the quality of their models. PRIMO provides functionality that allows users to also model ligands and ions in complex with their protein targets. Herein, we assess the accuracy of the fully automated capabilities of the server, including a comparative analysis of the available alignment programs, as well as of the refinement levels used during modeling. The tests presented here demonstrate the reliability of the PRIMO server when producing a large number of protein models. While PRIMO does focus on user involvement in the homology modeling process, the results indicate that in the presence of suitable templates, good quality models can be produced even without user intervention. This gives an idea of the base level accuracy of PRIMO, which users can improve upon by adjusting parameters in their modeling runs. The accuracy of PRIMO’s automated scripts is being continuously evaluated by the CAMEO (Continuous Automated Model EvaluatiOn) project. The PRIMO site is free for non-commercial use and can be accessed at https://primo.rubi.ru.ac.za/. PMID:27855192

  3. PRIMO: An Interactive Homology Modeling Pipeline.

    Science.gov (United States)

    Hatherley, Rowan; Brown, David K; Glenister, Michael; Tastan Bishop, Özlem

    2016-01-01

    The development of automated servers to predict the three-dimensional structure of proteins has seen much progress over the years. These servers make calculations simpler, but largely exclude users from the process. In this study, we present the PRotein Interactive MOdeling (PRIMO) pipeline for homology modeling of protein monomers. The pipeline eases the multi-step modeling process, and reduces the workload required by the user, while still allowing engagement from the user during every step. Default parameters are given for each step, which can either be modified or supplemented with additional external input. PRIMO has been designed for users of varying levels of experience with homology modeling. The pipeline incorporates a user-friendly interface that makes it easy to alter parameters used during modeling. During each stage of the modeling process, the site provides suggestions for novice users to improve the quality of their models. PRIMO provides functionality that allows users to also model ligands and ions in complex with their protein targets. Herein, we assess the accuracy of the fully automated capabilities of the server, including a comparative analysis of the available alignment programs, as well as of the refinement levels used during modeling. The tests presented here demonstrate the reliability of the PRIMO server when producing a large number of protein models. While PRIMO does focus on user involvement in the homology modeling process, the results indicate that in the presence of suitable templates, good quality models can be produced even without user intervention. This gives an idea of the base level accuracy of PRIMO, which users can improve upon by adjusting parameters in their modeling runs. The accuracy of PRIMO's automated scripts is being continuously evaluated by the CAMEO (Continuous Automated Model EvaluatiOn) project. The PRIMO site is free for non-commercial use and can be accessed at https://primo.rubi.ru.ac.za/.

  4. Method of and apparatus for modeling interactions

    Science.gov (United States)

    Budge, Kent G.

    2004-01-13

    A method and apparatus for modeling interactions can accurately model tribological and other properties and accommodate topological disruptions. Two portions of a problem space are represented, a first with a Lagrangian mesh and a second with an ALE mesh. The ALE and Lagrangian meshes are constructed so that each node on the surface of the Lagrangian mesh is in a known correspondence with adjacent nodes in the ALE mesh. The interaction can be predicted for a time interval. Material flow within the ALE mesh can accurately model complex interactions such as bifurcation. After prediction, nodes in the ALE mesh in correspondence with nodes on the surface of the Lagrangian mesh can be mapped so that they are once again adjacent to their corresponding Lagrangian mesh nodes. The ALE mesh can then be smoothed to reduce mesh distortion that might reduce the accuracy or efficiency of subsequent prediction steps. The process, from prediction through mapping and smoothing, can be repeated until a terminal condition is reached.

  5. Modeling Users' Experiences with Interactive Systems

    CERN Document Server

    Karapanos, Evangelos

    2013-01-01

    Over the past decade the field of Human-Computer Interaction has evolved from the study of the usability of interactive products towards a more holistic understanding of how they may mediate desired human experiences.  This book identifies the notion of diversity in usersʼ experiences with interactive products and proposes methods and tools for modeling this along two levels: (a) interpersonal diversity in usersʽ responses to early conceptual designs, and (b) the dynamics of usersʼ experiences over time. The Repertory Grid Technique is proposed as an alternative to standardized psychometric scales for modeling interpersonal diversity in usersʼ responses to early concepts in the design process, and new Multi-Dimensional Scaling procedures are introduced for modeling such complex quantitative data. iScale, a tool for the retrospective assessment of usersʼ experiences over time is proposed as an alternative to longitudinal field studies, and a semi-automated technique for the analysis of the elicited exper...

  6. Nagaoka's atomic model and hyperfine interactions.

    Science.gov (United States)

    Inamura, Takashi T

    2016-01-01

    The prevailing view of Nagaoka's "Saturnian" atom is so misleading that today many people have an erroneous picture of Nagaoka's vision. They believe it to be a system involving a 'giant core' with electrons circulating just outside. Actually, though, in view of the Coulomb potential related to the atomic nucleus, Nagaoka's model is exactly the same as Rutherford's. This is true of the Bohr atom, too. To give proper credit, Nagaoka should be remembered together with Rutherford and Bohr in the history of the atomic model. It is also pointed out that Nagaoka was a pioneer of understanding hyperfine interactions in order to study nuclear structure.

  7. Isard's contributions to spatial interaction modeling

    Science.gov (United States)

    O'Kelly, M. E.

    . This short review, surveys Isard's role in promoting what has become known as spatial interaction modeling. Some contextual information on the milieu from which his work emerged is given, together with a selected number of works that are judged to have been influenced (directly and indirectly) by his work. It is suggested that this burgeoning field owes a lot to the foundations laid in the gravity model chapter of ``Methods''. The review is supplemented by a rather extensive bibliography of additional works that are indicative of the breadth of the impact of this field.

  8. IMP 8 magnetosheath field comparisons with models

    Directory of Open Access Journals (Sweden)

    Z. Kaymaz

    Full Text Available This study presents cross-sectional vector maps of the magnetic field derived from IMP 8 magnetometer in the magnetosheath at 30 Re behind the Earth. In addition the vector patterns of the magnetosheath field for northward, southward, and east-west interplanetary magnetic field (IMF directions are qualitatively compared with those obtained from the Spreiter-Stahara gas dynamic (GD and Fedder-Lyon magnetohydrodynamic models (MHD. The main purpose is to display the cross-sectional differences in relation to the dayside merging with different IMF directions, allowing the reader to make direct visual comparisons of the vector patterns. It is seen that for east-west IMF directions, the data-based and MHD-based patterns differ noticeably in a similar way from the GD model, presumably reflecting the influence of dayside magnetic merging of the Earth's magnetic field with the y-component of the interplanetary magnetic field. All three northward IMF cross sections show comparable field draping patterns as expected for a closed magnetosphere. For southward IMF case, on the other hand, differences between the three cross-sectional patterns are greater as seen in the field vector sizes and directions, especially closer to the magnetopause where more disturbed magnetospheric conditions are known to be exist. The data comparisons with the MHD and GD models show that the differences result from the magnetic field-flow coupling and that the effects of dayside reconnection are present in IMP 8 magnetic field measurements.

    Keywords. Vector maps · IMP 8 magnetometer · Inter-planetary magnetic fields

  9. Visible Geology - Interactive online geologic block modelling

    Science.gov (United States)

    Cockett, R.

    2012-12-01

    Geology is a highly visual science, and many disciplines require spatial awareness and manipulation. For example, interpreting cross-sections, geologic maps, or plotting data on a stereonet all require various levels of spatial abilities. These skills are often not focused on in undergraduate geoscience curricula and many students struggle with spatial relations, manipulations, and penetrative abilities (e.g. Titus & Horsman, 2009). A newly developed program, Visible Geology, allows for students to be introduced to many geologic concepts and spatial skills in a virtual environment. Visible Geology is a web-based, three-dimensional environment where students can create and interrogate their own geologic block models. The program begins with a blank model, users then add geologic beds (with custom thickness and color) and can add geologic deformation events like tilting, folding, and faulting. Additionally, simple intrusive dikes can be modelled, as well as unconformities. Students can also explore the interaction of geology with topography by drawing elevation contours to produce their own topographic models. Students can not only spatially manipulate their model, but can create cross-sections and boreholes to practice their visual penetrative abilities. Visible Geology is easy to access and use, with no downloads required, so it can be incorporated into current, paper-based, lab activities. Sample learning activities are being developed that target introductory and structural geology curricula with learning objectives such as relative geologic history, fault characterization, apparent dip and thickness, interference folding, and stereonet interpretation. Visible Geology provides a richly interactive, and immersive environment for students to explore geologic concepts and practice their spatial skills.; Screenshot of Visible Geology showing folding and faulting interactions on a ridge topography.

  10. Comparing models of star formation simulating observed interacting galaxies

    Science.gov (United States)

    Quiroga, L. F.; Muñoz-Cuartas, J. C.; Rodrigues, I.

    2017-07-01

    In this work, we make a comparison between different models of star formation to reproduce observed interacting galaxies. We use observational data to model the evolution of a pair of galaxies undergoing a minor merger. Minor mergers represent situations weakly deviated from the equilibrium configuration but significant changes in star fomation (SF) efficiency can take place, then, minor mergers provide an unique scene to study SF in galaxies in a realistic but yet simple way. Reproducing observed systems also give us the opportunity to compare the results of the simulations with observations, which at the end can be used as probes to characterize the models of SF implemented in the comparison. In this work we compare two different star formation recipes implemented in Gadget3 and GIZMO codes. Both codes share the same numerical background, and differences arise mainly in the star formation recipe they use. We use observations from Pico dos Días and GEMINI telescopes and show how we use observational data of the interacting pair in AM2229-735 to characterize the interacting pair. Later we use this information to simulate the evolution of the system to finally reproduce the observations: Mass distribution, morphology and main features of the merger-induced star formation burst. We show that both methods manage to reproduce roughly the star formation activity. We show, through a careful study, that resolution plays a major role in the reproducibility of the system. In that sense, star formation recipe implemented in GIZMO code has shown a more robust performance. Acknowledgements: This work is supported by Colciencias, Doctorado Nacional - 617 program.

  11. Motion Model Employment using interacting Motion Model Algorithm

    DEFF Research Database (Denmark)

    Hussain, Dil Muhammad Akbar

    2006-01-01

    The paper presents a simulation study to track a maneuvering target using a selective approach in choosing Interacting Multiple Models (IMM) algorithm to provide a wider coverage to track such targets.  Initially, there are two motion models in the system to track a target.  Probability of each...... model being correct is computed through a likelihood function for each model.  The study presented a simple technique to introduce additional models into the system using deterministic acceleration which basically defines the dynamics of the system.  Therefore, based on this value more motion models can...... be employed to increase the coverage.  Finally, the combined estimate is obtained using posteriori probabilities from different filter models.   The implemented approach provides an adaptive scheme for selecting various number of motion models.  Motion model description is important as it defines the kind...

  12. Comparisons of power of statistical methods for gene-environment interaction analyses.

    Science.gov (United States)

    Ege, Markus J; Strachan, David P

    2013-10-01

    Any genome-wide analysis is hampered by reduced statistical power due to multiple comparisons. This is particularly true for interaction analyses, which have lower statistical power than analyses of associations. To assess gene-environment interactions in population settings we have recently proposed a statistical method based on a modified two-step approach, where first genetic loci are selected by their associations with disease and environment, respectively, and subsequently tested for interactions. We have simulated various data sets resembling real world scenarios and compared single-step and two-step approaches with respect to true positive rate (TPR) in 486 scenarios and (study-wide) false positive rate (FPR) in 252 scenarios. Our simulations confirmed that in all two-step methods the two steps are not correlated. In terms of TPR, two-step approaches combining information on gene-disease association and gene-environment association in the first step were superior to all other methods, while preserving a low FPR in over 250 million simulations under the null hypothesis. Our weighted modification yielded the highest power across various degrees of gene-environment association in the controls. An optimal threshold for step 1 depended on the interacting allele frequency and the disease prevalence. In all scenarios, the least powerful method was to proceed directly to an unbiased full interaction model, applying conventional genome-wide significance thresholds. This simulation study confirms the practical advantage of two-step approaches to interaction testing over more conventional one-step designs, at least in the context of dichotomous disease outcomes and other parameters that might apply in real-world settings.

  13. Comments on interactions in the SUSY models

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Sudhaker; Mandal, Bhabani Prasad [Banaras Hindu University, Department of Physics, Varanasi (India); Reshetnyak, Alexander [Institute of Strength Physics and Materials Science of SB RAS, Tomsk (Russian Federation)

    2016-07-15

    We consider special supersymmetry (SUSY) transformations with m generators /leftarrow s{sub α}, for some class of models and study the physical consequences when making the Grassmann-odd transformations to form an Abelian supergroup with finite parameters and a set of group-like elements with finite parameters being functionals of the field variables. The SUSY-invariant path integral measure within conventional quantization scheme leads to the appearance of the Jacobian under a change of variables generated by such SUSY transformations, which is explicitly calculated. The Jacobian implies, first of all, the appearance of trivial interactions in the transformed action, and, second, the presence of a modified Ward identity which reduces to the standard Ward identities in the case of constant parameters. We examine the case of the N = 1 and N = 2 supersymmetric harmonic oscillators to illustrate the general concept by a simple free model with (1, 1) physical degrees of freedom. It is shown that the interaction terms U{sub tr} have a corresponding SUSY-exact form: U{sub tr} = (V{sub (1)} /leftarrow s; V{sub (2)} /leftarrow anti s /leftarrow s) generated naturally under such generalized formulation. We argue that the case of a non-trivial interaction cannot be obtained in such a way. (orig.)

  14. Modeling of physical human–robot interaction

    Directory of Open Access Journals (Sweden)

    Alexandre Campeau-Lecours

    2016-09-01

    Full Text Available Enhancement of human performance using an intelligent assist device is becoming more common. In order to achieve effective augmentation of human capacity, cooperation between human and robot must be safe and very intuitive. Ensuring such collaboration remains a challenge, especially when admittance control is used. This paper addresses the issues of transparency and human perception coming from vibration in admittance control schemes. Simulation results obtained with our suggested improved model using an admittance controller are presented, then four models using transfer functions are discussed in detail and evaluated as a means of simulating physical human–robot interaction using admittance control. The simulation and experimental results are then compared in order to assess the validity and limitations of the proposed models in the case of a four-degree-of-freedom intelligent assist device designed for large payload.

  15. Calogero model with Yukawa like interaction

    CERN Document Server

    Kessabi, M; Sebbata, H; Kessabi, Mohammed; Saidi, El Hassan; Sebbata, Hanane

    2006-01-01

    We study an extension of one dimensional Calogero model involving strongly coupled and electrically charged particles. Besides Calogero term $\\frac{g}{% 2x^{2}}$, there is an extra factor described by a Yukawa like coupling modeling short distance interactions. Mimicking Calogero analysis and using developments in formal series of the wave function $\\Psi (x) $ factorised as $x^{\\epsilon}\\Phi (x) $ with $\\epsilon (\\epsilon -1) =g$, we develop a technique to approach the spectrum of the generalized system and show that information on full spectrum is captured by $\\Phi (x) $ and $\\Phi ^{\\prime \\prime}(x) $ at the singular point $x=0$ of the potential. Convergence of $% \\int dx| \\Psi (x) | ^{2}$ requires $\\epsilon >-{1/2}$ and is shown to be sensitive to the zero mode of $\\Phi (x) $ at $x=0$. \\textbf{Key words}: \\textit{Hamitonian systems, quantum integrability, Calogero model, Yukawa like potential.}

  16. On dark degeneracy and interacting models

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, S.; Borges, H.A., E-mail: saulo.carneiro@pq.cnpq.br, E-mail: humberto@ufba.br [Instituto de Física, Universidade Federal da Bahia, Campus de Ondina, Salvador, BA, 40210-340 Brazil (Brazil)

    2014-06-01

    Cosmological background observations cannot fix the dark energy equation of state, which is related to a degeneracy in the definition of the dark sector components. Here we show that this degeneracy can be broken at perturbation level by imposing two observational properties on dark matter. First, dark matter is defined as the clustering component we observe in large scale structures. This definition is meaningful only if dark energy is unperturbed, which is achieved if we additionally assume, as a second condition, that dark matter is cold, i.e. non-relativistic. As a consequence, dark energy models with equation-of-state parameter −1 ≤ ω < 0 are reduced to two observationally distinguishable classes with ω = −1, equally competitive when tested against observations. The first comprises the ΛCDM model with constant dark energy density. The second consists of interacting models with an energy flux from dark energy to dark matter.

  17. Measuring dark matter by modeling interacting galaxies

    CERN Document Server

    Petsch, H P; Theis, Ch

    2009-01-01

    The dark matter content of galaxies is usually determined from galaxies in dynamical equilibrium, mainly from rotationally supported galactic components. Such determinations restrict measurements to special regions in galaxies, e.g. the galactic plane(s), whereas other regions are not probed at all. Interacting galaxies offer an alternative, because extended tidal tails often probe outer or off-plane regions of galaxies. However, these systems are neither in dynamical equilibrium nor simple, because they are composed of two or more galaxies, by this increasing the associated parameter space.We present our genetic algorithm based modeling tool which allows to investigate the extended parameter space of interacting galaxies. From these studies, we derive the dynamical history of (well observed) galaxies. Among other parameters we constrain the dark matter content of the involved galaxies. We demonstrate the applicability of this strategy with examples ranging from stellar streams around theMilkyWay to extended ...

  18. Interacting damage models mapped onto ising and percolation models

    Energy Technology Data Exchange (ETDEWEB)

    Toussaint, Renaud; Pride, Steven R.

    2004-03-23

    The authors introduce a class of damage models on regular lattices with isotropic interactions between the broken cells of the lattice. Quasistatic fiber bundles are an example. The interactions are assumed to be weak, in the sense that the stress perturbation from a broken cell is much smaller than the mean stress in the system. The system starts intact with a surface-energy threshold required to break any cell sampled from an uncorrelated quenched-disorder distribution. The evolution of this heterogeneous system is ruled by Griffith's principle which states that a cell breaks when the release in potential (elastic) energy in the system exceeds the surface-energy barrier necessary to break the cell. By direct integration over all possible realizations of the quenched disorder, they obtain the probability distribution of each damage configuration at any level of the imposed external deformation. They demonstrate an isomorphism between the distributions so obtained and standard generalized Ising models, in which the coupling constants and effective temperature in the Ising model are functions of the nature of the quenched-disorder distribution and the extent of accumulated damage. In particular, they show that damage models with global load sharing are isomorphic to standard percolation theory, that damage models with local load sharing rule are isomorphic to the standard ising model, and draw consequences thereof for the universality class and behavior of the autocorrelation length of the breakdown transitions corresponding to these models. they also treat damage models having more general power-law interactions, and classify the breakdown process as a function of the power-law interaction exponent. Last, they also show that the probability distribution over configurations is a maximum of Shannon's entropy under some specific constraints related to the energetic balance of the fracture process, which firmly relates this type of quenched-disorder based

  19. Modelling family 2 cystatins and their interaction with papain.

    Science.gov (United States)

    Nandy, Suman Kumar; Bhuyan, Rajabrata; Seal, Alpana

    2013-01-01

    Cystatins are extensively studied cysteine protease inhibitors, found in wide range of organisms with highly conserved structural folds. S-type of cystatins is well known for their abundance in saliva, high selectivity and poorer activity towards host cysteine proteases in comparison to their immediate ancestor cystatin C. Despite more than 90% sequence similarity, the members of this group show highly dissimilar binding affinity towards papain. Cystatin M/E is a potent inhibitor of legumain and papain like cysteine proteases and recognized for its involvement in skin barrier formation and potential role as a tumor suppressor gene. However, the structures of these proteins and their complexes with papain or legumain are still unknown. In the present study, we have employed computational methods to get insight into the interactions between papain and cystatins. Three-dimensional structures of the cystatins are generated by homology modelling, refined with molecular dynamics simulation, validated through numerous web servers and finally complexed with papain using ZDOCK algorithm in Discovery Studio. A high degree of shape complementarity is observed within the complexes, stabilized by numerous hydrogen bonds (HB) and hydrophobic interactions. Using interaction energy, HB and solvent accessible surface area analyses, we have identified a series of key residues that may be involved in papain-cystatin interaction. Differential approaches of cystatins towards papain are also noticed which are possibly responsible for diverse inhibitory activity within the group. These findings will improve our understanding of fundamental inhibitory mechanisms of cystatin and provide clues for further research.

  20. Item Response Modeling of Paired Comparison and Ranking Data

    Science.gov (United States)

    Maydeu-Olivares, Alberto; Brown, Anna

    2010-01-01

    The comparative format used in ranking and paired comparisons tasks can significantly reduce the impact of uniform response biases typically associated with rating scales. Thurstone's (1927, 1931) model provides a powerful framework for modeling comparative data such as paired comparisons and rankings. Although Thurstonian models are generally…

  1. MDA based-approach for UML Models Complete Comparison

    CERN Document Server

    Chaouni, Samia Benabdellah; Mouline, Salma

    2011-01-01

    If a modeling task is distributed, it will frequently be necessary to integrate models developed by different team members. Problems occur in the models integration step and particularly, in the comparison phase of the integration. This issue had been discussed in several domains and various models. However, previous approaches have not correctly handled the semantic comparison. In the current paper, we provide a MDA-based approach for models comparison which aims at comparing UML models. We develop an hybrid approach which takes into account syntactic, semantic and structural comparison aspects. For this purpose, we use the domain ontology as well as other resources such as dictionaries. We propose a decision support system which permits the user to validate (or not) correspondences extracted in the comparison phase. For implementation, we propose an extension of the generic correspondence metamodel AMW in order to transform UML models to the correspondence model.

  2. Convergent series for lattice models with polynomial interactions

    Directory of Open Access Journals (Sweden)

    Aleksandr S. Ivanov

    2017-01-01

    Full Text Available The standard perturbative weak-coupling expansions in lattice models are asymptotic. The reason for this is hidden in the incorrect interchange of the summation and integration. However, substituting the Gaussian initial approximation of the perturbative expansions by a certain interacting model or regularizing original lattice integrals, one can construct desired convergent series. In this paper we develop methods, which are based on the joint and separate utilization of the regularization and new initial approximation. We prove, that the convergent series exist and can be expressed as re-summed standard perturbation theory for any model on the finite lattice with the polynomial interaction of even degree. We discuss properties of such series and study their applicability to practical computations on the example of the lattice ϕ4-model. We calculate 〈ϕn2〉 expectation value using the convergent series, the comparison of the results with the Borel re-summation and Monte Carlo simulations shows a good agreement between all these methods.

  3. How can model comparison help improving species distribution models?

    Science.gov (United States)

    Gritti, Emmanuel Stephan; Gaucherel, Cédric; Crespo-Perez, Maria-Veronica; Chuine, Isabelle

    2013-01-01

    Today, more than ever, robust projections of potential species range shifts are needed to anticipate and mitigate the impacts of climate change on biodiversity and ecosystem services. Such projections are so far provided almost exclusively by correlative species distribution models (correlative SDMs). However, concerns regarding the reliability of their predictive power are growing and several authors call for the development of process-based SDMs. Still, each of these methods presents strengths and weakness which have to be estimated if they are to be reliably used by decision makers. In this study we compare projections of three different SDMs (STASH, LPJ and PHENOFIT) that lie in the continuum between correlative models and process-based models for the current distribution of three major European tree species, Fagussylvatica L., Quercusrobur L. and Pinussylvestris L. We compare the consistency of the model simulations using an innovative comparison map profile method, integrating local and multi-scale comparisons. The three models simulate relatively accurately the current distribution of the three species. The process-based model performs almost as well as the correlative model, although parameters of the former are not fitted to the observed species distributions. According to our simulations, species range limits are triggered, at the European scale, by establishment and survival through processes primarily related to phenology and resistance to abiotic stress rather than to growth efficiency. The accuracy of projections of the hybrid and process-based model could however be improved by integrating a more realistic representation of the species resistance to water stress for instance, advocating for pursuing efforts to understand and formulate explicitly the impact of climatic conditions and variations on these processes.

  4. Mud-Wave Interaction: A Viscoelastic Model

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This study is devoted to the interaction between water surface waves and a thin layer of viscoelastic mud on the bottom. On the assumption that the mud layer is comparable in thickness with the wave boundary layer and is much smaller than the wavelength, a two-layer Stokes boundary layer model is adopted to determine the mud motions under the waves. Analytical expressions are derived for the near-bottom water and mud velocity fields, surface wave-damping rate, and interface wave amplitude and phase lag. Examined in particular is how these kinematic quantities may depend on the viscous and elastic properties of the mud.

  5. Numerical investigation of two interacting parallel thruster-plumes and comparison to experiment

    Science.gov (United States)

    Grabe, Martin; Holz, André; Ziegenhagen, Stefan; Hannemann, Klaus

    2014-12-01

    Clusters of orbital thrusters are an attractive option to achieve graduated thrust levels and increased redundancy with available hardware, but the heavily under-expanded plumes of chemical attitude control thrusters placed in close proximity will interact, leading to a local amplification of downstream fluxes and of back-flow onto the spacecraft. The interaction of two similar, parallel, axi-symmetric cold-gas model thrusters has recently been studied in the DLR High-Vacuum Plume Test Facility STG under space-like vacuum conditions, employing a Patterson-type impact pressure probe with slot orifice. We reproduce a selection of these experiments numerically, and emphasise that a comparison of numerical results to the measured data is not straight-forward. The signal of the probe used in the experiments must be interpreted according to the degree of rarefaction and local flow Mach number, and both vary dramatically thoughout the flow-field. We present a procedure to reconstruct the probe signal by post-processing the numerically obtained flow-field data and show that agreement to the experimental results is then improved. Features of the investigated cold-gas thruster plume interaction are discussed on the basis of the numerical results.

  6. Interactive Inconsistency Fixing in Feature Modeling

    Institute of Scientific and Technical Information of China (English)

    王波; 熊英飞; 胡振江; 赵海燕; 张伟; 梅宏

    2014-01-01

    Feature models have been widely adopted to reuse the requirements of a set of similar products in a domain. In feature models’ construction, one basic task is to ensure the consistency of feature models, which often involves detecting and fixing of inconsistencies in feature models. While many approaches have been proposed, most of them focus on detecting inconsistencies rather than fixing inconsistencies. In this paper, we propose a novel dynamic-priority based approach to interactively fixing inconsistencies in feature models, and report an implementation of a system that not only automatically recommends a solution to fixing inconsistencies but also supports domain analysts to gradually reach the desirable solution by dynamically adjusting priorities of constraints. The key technical contribution is, as far as we are aware, the first application of the constraint hierarchy theory to feature modeling, where the degree of domain analysts’ confidence on constraints is expressed by using priority and inconsistencies are resolved by deleting one or more lower-priority constraints. Two case studies demonstrate the usability and scalability (effciency) of our new approach.

  7. Realistic model for radiation-matter interaction

    CERN Document Server

    Pakula, R A

    2004-01-01

    This paper presents a realistic model that describes radiation-matter interactions. This is achieved by a generalization of first quantization, where the Maxwell equations are interpreted as the electromagnetic component of the Schrodinger equation. This picture is complemented by the consideration of electrons and photons as real particles in three-dimensional space, following guiding conditions derived from the particle-wave-functions to which they are associated. The guiding condition for the electron is taken from Bohmian mechanics, while the photon velocity is defined as the ratio between the Poynting vector and the electromagnetic energy density. The case of many particles is considered, taking into account their statistical properties. The formalism is applied to a two level system, providing an intuitive description for spontaneous emission, Lamb shift, scattering, absorption, dispersion, resonance fluorescence and vacuum fields. This model describes quantum jumps by the entanglement between the photo...

  8. Laser interaction with biological material mathematical modeling

    CERN Document Server

    Kulikov, Kirill

    2014-01-01

    This book covers the principles of laser interaction with biological cells and tissues of varying degrees of organization. The problems of biomedical diagnostics are considered. Scattering of laser irradiation of blood cells is modeled for biological structures (dermis, epidermis, vascular plexus). An analytic theory is provided which is based on solving the wave equation for the electromagnetic field. It allows the accurate analysis of interference effects arising from the partial superposition of scattered waves. Treated topics of mathematical modeling are: optical characterization of biological tissue with large-scale and small-scale inhomogeneities in the layers, heating blood vessel under laser irradiation incident on the outer surface of the skin and thermo-chemical denaturation of biological structures at the example of human skin.

  9. Convex Modeling of Interactions with Strong Heredity

    Science.gov (United States)

    Haris, Asad; Witten, Daniela; Simon, Noah

    2015-01-01

    We consider the task of fitting a regression model involving interactions among a potentially large set of covariates, in which we wish to enforce strong heredity. We propose FAMILY, a very general framework for this task. Our proposal is a generalization of several existing methods, such as VANISH [Radchenko and James, 2010], hierNet [Bien et al., 2013], the all-pairs lasso, and the lasso using only main effects. It can be formulated as the solution to a convex optimization problem, which we solve using an efficient alternating directions method of multipliers (ADMM) algorithm. This algorithm has guaranteed convergence to the global optimum, can be easily specialized to any convex penalty function of interest, and allows for a straightforward extension to the setting of generalized linear models. We derive an unbiased estimator of the degrees of freedom of FAMILY, and explore its performance in a simulation study and on an HIV sequence data set. PMID:28316461

  10. Interaction of Mastoparan with Model Membranes

    Science.gov (United States)

    Haloot, Justin

    2010-10-01

    The use of antimicrobial agents began during the 20th century to reduce the effects of infectious diseases. Since the 1990s, antimicrobial resistance has become an ever-increasing global problem. Our laboratory recently found that small antimicrobial peptides (AMPs) have potent antimicrobial activity against a wide range of Gram-negative and Gram-positive organisms including antibiotic resistant organisms. These AMPs are potential therapeutic agents against the growing problem of antimicrobial resistance. AMPs are small peptides produced by plants, insects and animals. Several hypotheses concede that these peptides cause some type of structural perturbations and increased membrane permeability in bacteria however, how AMPs kill bacteria remains unclear. The goal of this study was to design an assay that would allow us to evaluate and monitor the pore forming ability of an AMP, Mastoparan, on model membrane structures called liposomes. Development of this model will facilitate the study of how mastoparan and related AMPs interact with the bacterial membrane.

  11. Modeling the Enceladus plume--plasma interaction

    CERN Document Server

    Fleshman, B L; Bagenal, F

    2010-01-01

    We investigate the chemical interaction between Saturn's corotating plasma and Enceladus' volcanic plumes. We evolve plasma as it passes through a prescribed H2O plume using a physical chemistry model adapted for water-group reactions. The flow field is assumed to be that of a plasma around an electrically-conducting obstacle centered on Enceladus and aligned with Saturn's magnetic field, consistent with Cassini magnetometer data. We explore the effects on the physical chemistry due to: (1) a small population of hot electrons; (2) a plasma flow decelerated in response to the pickup of fresh ions; (3) the source rate of neutral H2O. The model confirms that charge exchange dominates the local chemistry and that H3O+ dominates the water-group composition downstream of the Enceladus plumes. We also find that the amount of fresh pickup ions depends heavily on both the neutral source strength and on the presence of a persistent population of hot electrons.

  12. Interaction of Defensins with Model Cell Membranes

    Science.gov (United States)

    Sanders, Lori K.; Schmidt, Nathan W.; Yang, Lihua; Mishra, Abhijit; Gordon, Vernita D.; Selsted, Michael E.; Wong, Gerard C. L.

    2009-03-01

    Antimicrobial peptides (AMPs) comprise a key component of innate immunity for a wide range of multicellular organisms. For many AMPs, activity comes from their ability to selectively disrupt and lyse bacterial cell membranes. There are a number of proposed models for this action, but the detailed molecular mechanism of selective membrane permeation remains unclear. Theta defensins are circularized peptides with a high degree of selectivity. We investigate the interaction of model bacterial and eukaryotic cell membranes with theta defensins RTD-1, BTD-7, and compare them to protegrin PG-1, a prototypical AMP, using synchrotron small angle x-ray scattering (SAXS). The relationship between membrane composition and peptide induced changes in membrane curvature and topology is examined. By comparing the membrane phase behavior induced by these different peptides we will discuss the importance of amino acid composition and placement on membrane rearrangement.

  13. Photometry and models of selected main belt asteroids: IX. Introducing interactive service for asteroid models (ISAM)

    DEFF Research Database (Denmark)

    Marciniak, A.; Bartczak, P.; Santana-Ros, T.

    2012-01-01

    from other observing/modelling techniques, we created an on-line service where we allow the inversion models to be orientated interactively. Results. Our sample of objects is quite representative, containing both relatively fast and slow rotators with highly and lowly inclined spin axes. With this work...... occultations, or space probe imaging. Aims. During our ongoing work to increase the set of asteroids with known spin and shape parameters, there appeared a need for displaying the model plane-of-sky orientations for specific epochs to compare models from different techniques. It would also be instructive...... to be able to track how the complex lightcurves are produced by various asteroid shapes. Methods. Basing our analysis on an extensive photometric observational dataset, we obtained eight asteroid models with the convex lightcurve inversion method. To enable comparison of the photometric models with those...

  14. Repetition-based Interactive Facade Modeling

    KAUST Repository

    AlHalawani, Sawsan

    2012-07-01

    Modeling and reconstruction of urban environments has gained researchers attention throughout the past few years. It spreads in a variety of directions across multiple disciplines such as image processing, computer graphics and computer vision as well as in architecture, geoscience and remote sensing. Having a virtual world of our real cities is very attractive in various directions such as entertainment, engineering, governments among many others. In this thesis, we address the problem of processing a single fa cade image to acquire useful information that can be utilized to manipulate the fa cade and generate variations of fa cade images which can be later used for buildings\\' texturing. Typical fa cade structures exhibit a rectilinear distribution where in windows and other elements are organized in a grid of horizontal and vertical repetitions of similar patterns. In the firt part of this thesis, we propose an efficient algorithm that exploits information obtained from a single image to identify the distribution grid of the dominant elements i.e. windows. This detection method is initially assisted with the user marking the dominant window followed by an automatic process for identifying its repeated instances which are used to define the structure grid. Given the distribution grid, we allow the user to interactively manipulate the fa cade by adding, deleting, resizing or repositioning the windows in order to generate new fa cade structures. Having the utility for the interactive fa cade is very valuable to create fa cade variations and generate new textures for building models. Ultimately, there is a wide range of interesting possibilities of interactions to be explored.

  15. A simple model for studying interacting networks

    Science.gov (United States)

    Liu, Wenjia; Jolad, Shivakumar; Schmittmann, Beate; Zia, R. K. P.

    2011-03-01

    Many specific physical networks (e.g., internet, power grid, interstates), have been characterized in considerable detail, but in isolation from each other. Yet, each of these networks supports the functions of the others, and so far, little is known about how their interactions affect their structure and functionality. To address this issue, we consider two coupled model networks. Each network is relatively simple, with a fixed set of nodes, but dynamically generated set of links which has a preferred degree, κ . In the stationary state, the degree distribution has exponential tails (far from κ), an attribute which we can explain. Next, we consider two such networks with different κ 's, reminiscent of two social groups, e.g., extroverts and introverts. Finally, we let these networks interact by establishing a controllable fraction of cross links. The resulting distribution of links, both within and across the two model networks, is investigated and discussed, along with some potential consequences for real networks. Supported in part by NSF-DMR-0705152 and 1005417.

  16. Interaction of Artepillin C with model membranes.

    Science.gov (United States)

    Pazin, Wallance Moreira; Olivier, Danilo da Silva; Vilanova, Neus; Ramos, Ana Paula; Voets, Ilja Karina; Soares, Ademilson Espencer Egea; Ito, Amando Siuiti

    2017-05-01

    Green propolis, a mixture of beeswax and resinous compounds processed by Apis mellifera, displays several pharmacological properties. Artepillin C, the major compound in green propolis, consists of two prenylated groups bound to a phenyl group. Several studies have focused on the therapeutic effects of Artepillin C, but there is no evidence that it interacts with amphiphilic aggregates to mimic cell membranes. We have experimentally and computationally examined the interaction between Artepillin C and model membranes composed of dimyristoylphosphatidylcholine (DMPC) because phosphatidylcholine (PC) is one of the most abundant phospholipids in eukaryotic cell membranes. PC is located in both outer and inner leaflets and has been used as a simplified membrane model and a non-specific target to study the action of amphiphilic molecules with therapeutic effects. Experimental results indicated that Artepillin C adsorbed onto the DMPC monolayers. Its presence in the lipid suspension pointed to an increased tendency toward unilamellar vesicles and to decreased bilayer thickness. Artepillin C caused point defects in the lipid structure, which eliminated the ripple phase and the pre-transition in thermotropic chain melting. According to molecular dynamics (MD) simulations, (1) Artepillin C aggregated in the aqueous phase before it entered the bilayer; (2) Artepillin C was oriented along the direction normal to the surface; (3) the negatively charged group on Artepillin C was accommodated in the polar region of the membrane; and (4) thinner regions emerged around the Artepillin C molecules. These results help an understanding of the molecular mechanisms underlying the biological action of propolis.

  17. Interactive informed consent: randomized comparison with paper consents.

    Directory of Open Access Journals (Sweden)

    Michael C Rowbotham

    Full Text Available Informed consent is the cornerstone of human research subject protection. Many subjects sign consent documents without understanding the study purpose, procedures, risks, benefits, and their rights. Proof of comprehension is not required and rarely obtained. Understanding might improve by using an interactive system with multiple options for hearing, viewing and reading about the study and the consent form at the subject's own pace with testing and immediate feedback. This prospective randomized study compared the IRB-approved paper ICF for an actual clinical research study with an interactive presentation of the same study and its associated consent form using an iPad device in two populations: clinical research professionals, and patients drawn from a variety of outpatient practice settings. Of the 90 participants, 69 completed the online test and survey questions the day after the session (maximum 36 hours post-session. Among research professionals (n = 14, there was a trend (p = .07 in the direction of iPad subjects testing better on the online test (mean correct  =  77% compared with paper subjects (mean correct = 57%. Among patients (n = 55, iPad subjects had significantly higher test scores than standard paper consent subjects (mean correct = 75% vs 58%, p < .001. For all subjects, the total time spent reviewing the paper consent was 13.2 minutes, significantly less than the average of 22.7 minutes total on the three components to be reviewed using the iPad (introductory video, consent form, interactive quiz. Overall satisfaction and overall enjoyment slightly favored the interactive iPad presentation. This study demonstrates that combining an introductory video, standard consent language, and an interactive quiz on a tablet-based system improves comprehension of research study procedures and risks.

  18. Classical interaction model for the water molecule.

    Science.gov (United States)

    Baranyai, András; Bartók, Albert

    2007-05-14

    The authors propose a new classical model for the water molecule. The geometry of the molecule is built on the rigid TIP5P model and has the experimental gas phase dipole moment of water created by four equal point charges. The model preserves its rigidity but the size of the charges increases or decreases following the electric field created by the rest of the molecules. The polarization is expressed by an electric field dependent nonlinear polarization function. The increasing dipole of the molecule slightly increases the size of the water molecule expressed by the oxygen-centered sigma parameter of the Lennard-Jones interaction. After refining the adjustable parameters, the authors performed Monte Carlo simulations to check the ability of the new model in the ice, liquid, and gas phases. They determined the density and internal energy of several ice polymorphs, liquid water, and gaseous water and calculated the heat capacity, the isothermal compressibility, the isobar heat expansion coefficients, and the dielectric constant of ambient water. They also determined the pair-correlation functions of ambient water and calculated the energy of the water dimer. The accuracy of theirs results was satisfactory.

  19. Model of Interatomic Interactions and Vibrational Spectrum of Tl2CaBa2Cu2O8

    Science.gov (United States)

    Belosludov, V. R.; Lavrentiev, M. Yu.; Syskin, S. A.

    A model of interatomic interactions of Tl2CaBa2Cu2O8, which takes into account coulombic interaction and covalent bonds, is presented. Vibrational spectrum is calculated using that model, and a comparison with experiments on Raman scattering is given.

  20. Integrating interactive computational modeling in biology curricula.

    Science.gov (United States)

    Helikar, Tomáš; Cutucache, Christine E; Dahlquist, Lauren M; Herek, Tyler A; Larson, Joshua J; Rogers, Jim A

    2015-03-01

    While the use of computer tools to simulate complex processes such as computer circuits is normal practice in fields like engineering, the majority of life sciences/biological sciences courses continue to rely on the traditional textbook and memorization approach. To address this issue, we explored the use of the Cell Collective platform as a novel, interactive, and evolving pedagogical tool to foster student engagement, creativity, and higher-level thinking. Cell Collective is a Web-based platform used to create and simulate dynamical models of various biological processes. Students can create models of cells, diseases, or pathways themselves or explore existing models. This technology was implemented in both undergraduate and graduate courses as a pilot study to determine the feasibility of such software at the university level. First, a new (In Silico Biology) class was developed to enable students to learn biology by "building and breaking it" via computer models and their simulations. This class and technology also provide a non-intimidating way to incorporate mathematical and computational concepts into a class with students who have a limited mathematical background. Second, we used the technology to mediate the use of simulations and modeling modules as a learning tool for traditional biological concepts, such as T cell differentiation or cell cycle regulation, in existing biology courses. Results of this pilot application suggest that there is promise in the use of computational modeling and software tools such as Cell Collective to provide new teaching methods in biology and contribute to the implementation of the "Vision and Change" call to action in undergraduate biology education by providing a hands-on approach to biology.

  1. Integrating interactive computational modeling in biology curricula.

    Directory of Open Access Journals (Sweden)

    Tomáš Helikar

    2015-03-01

    Full Text Available While the use of computer tools to simulate complex processes such as computer circuits is normal practice in fields like engineering, the majority of life sciences/biological sciences courses continue to rely on the traditional textbook and memorization approach. To address this issue, we explored the use of the Cell Collective platform as a novel, interactive, and evolving pedagogical tool to foster student engagement, creativity, and higher-level thinking. Cell Collective is a Web-based platform used to create and simulate dynamical models of various biological processes. Students can create models of cells, diseases, or pathways themselves or explore existing models. This technology was implemented in both undergraduate and graduate courses as a pilot study to determine the feasibility of such software at the university level. First, a new (In Silico Biology class was developed to enable students to learn biology by "building and breaking it" via computer models and their simulations. This class and technology also provide a non-intimidating way to incorporate mathematical and computational concepts into a class with students who have a limited mathematical background. Second, we used the technology to mediate the use of simulations and modeling modules as a learning tool for traditional biological concepts, such as T cell differentiation or cell cycle regulation, in existing biology courses. Results of this pilot application suggest that there is promise in the use of computational modeling and software tools such as Cell Collective to provide new teaching methods in biology and contribute to the implementation of the "Vision and Change" call to action in undergraduate biology education by providing a hands-on approach to biology.

  2. Interaction model of artificial fish in virtual environment

    Institute of Scientific and Technical Information of China (English)

    Meng Xiangsong; Ban Xiaojuan; Yin Yixin

    2008-01-01

    Conventional artificial fish has some shortages on the interaction with environment,other fish,and the animator.This article proposes a multi-tier interaction control model of artificial fish,realizes the interaction model through integration of virtual reality technology and Markov sequence,and provides a virtual marine world to describe the interaction between artificial fish and the virtual environment and the interaction between the artificial fish and the animator.Simulation results show that the interaction model owns not only the basic characteristics of virtual biology,but also has high trueness interaction function.

  3. Investigations and advanced concepts on gyrotron interaction modeling and simulations

    Science.gov (United States)

    Avramidis, K. A.

    2015-12-01

    In gyrotron theory, the interaction between the electron beam and the high frequency electromagnetic field is commonly modeled using the slow variables approach. The slow variables are quantities that vary slowly in time in comparison to the electron cyclotron frequency. They represent the electron momentum and the high frequency field of the resonant TE modes in the gyrotron cavity. For their definition, some reference frequencies need to be introduced. These include the so-called averaging frequency, used to define the slow variable corresponding to the electron momentum, and the carrier frequencies, used to define the slow variables corresponding to the field envelopes of the modes. From the mathematical point of view, the choice of the reference frequencies is, to some extent, arbitrary. However, from the numerical point of view, there are arguments that point toward specific choices, in the sense that these choices are advantageous in terms of simulation speed and accuracy. In this paper, the typical monochromatic gyrotron operation is considered, and the numerical integration of the interaction equations is performed by the trajectory approach, since it is the fastest, and therefore it is the one that is most commonly used. The influence of the choice of the reference frequencies on the interaction simulations is studied using theoretical arguments, as well as numerical simulations. From these investigations, appropriate choices for the values of the reference frequencies are identified. In addition, novel, advanced concepts for the definitions of these frequencies are addressed, and their benefits are demonstrated numerically.

  4. Comparison of tryptophan interactions to free and grafted BSA protein.

    Science.gov (United States)

    Garnier, F; Randon, J; Rocca, J L

    2000-04-28

    The binding of d- and l-tryptophan molecules to bovine serum albumin (BSA) protein has been studied using liquid chromatography and ultrafiltration in the pH range from 7 to 11. A hydrophobic interaction between tryptophan and BSA has been observed at pH 7.0 on BSA grafted chromatographic column. However, this interaction is negligible at higher pH for which the interaction to the stereospecific site was predominant. For both grafted and free proteins, the complexation mechanism was a competitive binding of d- and l-enantiomers on a single site. The apparent complexation constants for both d- and l-tryptophan show a maximum in the pH range 9-10. The variations of the apparent complexation constants versus pH were the result of the protonation of both the amino acid and a single site of the protein assuming that the complexation occurs between the zwitter-ionic amino acid form and the unprotonated BSA site. The apparent pK(BSA) is slightly shifted from 8.3 for grafted BSA protein to 9.4 for free BSA protein. This shift is presumably as a result of the different protein conformation.

  5. Geodynamo Modeling of Core-Mantle Interactions

    Science.gov (United States)

    Kuang, Wei-Jia; Chao, Benjamin F.; Smith, David E. (Technical Monitor)

    2001-01-01

    Angular momentum exchange between the Earth's mantle and core influences the Earth's rotation on time scales of decades and longer, in particular in the length of day (LOD) which have been measured with progressively increasing accuracy for the last two centuries. There are four possible coupling mechanisms for transferring the axial angular momentum across the core-mantle boundary (CMB): viscous, magnetic, topography, and gravitational torques. Here we use our scalable, modularized, fully dynamic geodynamo model for the core to assess the importance of these torques. This numerical model, as an extension of the Kuang-Bloxham model that has successfully simulated the generation of the Earth's magnetic field, is used to obtain numerical results in various physical conditions in terms of specific parameterization consistent with the dynamical processes in the fluid outer core. The results show that depending on the electrical conductivity of the lower mantle and the amplitude of the boundary topography at CMB, both magnetic and topographic couplings can contribute significantly to the angular momentum exchange. This implies that the core-mantle interactions are far more complex than has been assumed and that there is unlikely a single dominant coupling mechanism for the observed decadal LOD variation.

  6. Semiparametric modeling and analysis of longitudinal method comparison data.

    Science.gov (United States)

    Rathnayake, Lasitha N; Choudhary, Pankaj K

    2017-02-19

    Studies comparing two or more methods of measuring a continuous variable are routinely conducted in biomedical disciplines with the primary goal of measuring agreement between the methods. Often, the data are collected by following a cohort of subjects over a period of time. This gives rise to longitudinal method comparison data where there is one observation trajectory for each method on every subject. It is not required that observations from all methods be available at each observation time. The multiple trajectories on the same subjects are dependent. We propose modeling the trajectories nonparametrically through penalized regression splines within the framework of mixed-effects models. The model also uses random effects of subjects and their interactions to capture dependence in observations from the same subjects. It additionally allows the within-subject errors of each method to be correlated. It is fit using the method of maximum likelihood. Agreement between the methods is evaluated by performing inference on measures of agreement, such as concordance correlation coefficient and total deviation index, which are functions of parameters of the assumed model. Simulations indicate that the proposed methodology performs reasonably well for 30 or more subjects. Its application is illustrated by analyzing a dataset of percentage body fat measurements. Copyright © 2017 John Wiley & Sons, Ltd.

  7. Comparisons of treatment means when factors do not interact in two-factorial studies

    KAUST Repository

    Wei, Jiawei

    2011-05-06

    Scientists in the fields of nutrition and other biological sciences often design factorial studies to test the hypotheses of interest and importance. In the case of two-factorial studies, it is widely recognized that the analysis of factor effects is generally based on treatment means when the interaction of the factors is statistically significant, and involves multiple comparisons of treatment means. However, when the two factors do not interact, a common understanding among biologists is that comparisons among treatment means cannot or should not be made. Here, we bring this misconception into the attention of researchers. Additionally, we indicate what kind of comparisons among the treatment means can be performed when there is a nonsignificant interaction among two factors. Such information should be useful in analyzing the experimental data and drawing meaningful conclusions.

  8. Interactive exploration and modeling of large data sets: a case study with Venus light scattering data

    NARCIS (Netherlands)

    Wijk, J.J. van; Spoelder, H.J.W.; Knibbe, W.-J.J.; Shahroudi, K.E.

    1997-01-01

    We present a system where visualization and the control of the simulation are integrated to facilitate interactive exploration and modeling of large data sets. The system was developed to estimate properties of the atmosphere of Venus from comparison between measured and simulated data. Reuse of res

  9. Explicit and Dynamical Chiral Symmetry Bresking in an Effective Quark-Quark Interaction Model

    Institute of Scientific and Technical Information of China (English)

    宗红石; 吴小华; 侯丰尧; 赵恩广

    2004-01-01

    A method for obtaining the small current quark mass effect on the dressed quark propagator from an effective quark-quark interaction model is developed. Within this approach both the explicit and dynamical chiral symmetry breakings are analysed. A comparison with the previous results is given.

  10. Spectron: Graphical Model for Interacting With Timbre

    Directory of Open Access Journals (Sweden)

    Daniel Gómez

    2009-06-01

    Full Text Available The algorithms for creating and manipulating sound by electronic or digital means have grown in number and complexity since the creation of the first analog synthesizers. The techniques for visualizing these synthesis models have not increasingly grown with synthesizers, neither in hardware nor in software. In this paper, the possibilities to graphically represent and control timbre are presented, based on displaying the parameters involved in its synthesis model. A very simple data set was extracted from a commercial subtractive synthesizer and analyzed in two different approaches, dimensionality reduction and abstract data visualization. The results of these two different approaches were used as leads to design a synthesizer prototype: the Spectron synthesizer. This prototype uses an Amplitude vs. Frequency graphic as it´s main interface to give information about the timbre and to interact with it, it´s control offers a simplification in the amount of variables of a classic oscillator and expands its possibilities to generate additional timbre.

  11. Institute for Multiscale Modeling of Biological Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Paulaitis, Michael E; Garcia-Moreno, Bertrand; Lenhoff, Abraham

    2009-12-26

    The Institute for Multiscale Modeling of Biological Interactions (IMMBI) has two primary goals: Foster interdisciplinary collaborations among faculty and their research laboratories that will lead to novel applications of multiscale simulation and modeling methods in the biological sciences and engineering; and Building on the unique biophysical/biology-based engineering foundations of the participating faculty, train scientists and engineers to apply computational methods that collectively span multiple time and length scales of biological organization. The success of IMMBI will be defined by the following: Size and quality of the applicant pool for pre-doctoral and post-doctoral fellows; Academic performance; Quality of the pre-doctoral and post-doctoral research; Impact of the research broadly and to the DOE (ASCR program) mission; Distinction of the next career step for pre-doctoral and post-doctoral fellows; and Faculty collaborations that result from IMMBI activities. Specific details about accomplishments during the three years of DOE support for IMMBI have been documented in Annual Progress Reports (April 2005, June 2006, and March 2007) and a Report for a National Academy of Sciences Review (October 2005) that were submitted to DOE on the dates indicated. An overview of these accomplishments is provided.

  12. Comparison of amino acids interaction with gold nanoparticle.

    Science.gov (United States)

    Ramezani, Fatemeh; Amanlou, Massoud; Rafii-Tabar, Hashem

    2014-04-01

    The study of nanomaterial/biomolecule interface is an important emerging field in bionanoscience, and additionally in many biological processes such as hard-tissue growth and cell-surface adhesion. To have a deeper understanding of the amino acids/gold nanoparticle assemblies, the adsorption of these amino acids on the gold nanoparticles (GNPs) has been investigated via molecular dynamics simulation. In these simulations, all the constituent atoms of the nanoparticles were considered to be dynamic. The geometries of amino acids, when adsorbed on the nanoparticle, were studied and their flexibilities were compared with one another. The interaction of each of 20 amino acids was considered with 3 and 8 nm gold GNPs.

  13. Interactive Model Visualization for NET-VISA

    Science.gov (United States)

    Kuzma, H. A.; Arora, N. S.

    2013-12-01

    NET-VISA is a probabilistic system developed for seismic network processing of data measured on the International Monitoring System (IMS) of the Comprehensive nuclear Test Ban Treaty Organization (CTBTO). NET-VISA is composed of a Generative Model (GM) and an Inference Algorithm (IA). The GM is an explicit mathematical description of the relationships between various factors in seismic network analysis. Some of the relationships inside the GM are deterministic and some are statistical. Statistical relationships are described by probability distributions, the exact parameters of which (such as mean and standard deviation) are found by training NET-VISA using recent data. The IA uses the GM to evaluate the probability of various events and associations, searching for the seismic bulletin which has the highest overall probability and is consistent with a given set of measured arrivals. An Interactive Model Visualization tool (IMV) has been developed which makes 'peeking into' the GM simple and intuitive through a web-based interfaced. For example, it is now possible to access the probability distributions for attributes of events and arrivals such as the detection rate for each station for each of 14 phases. It also clarifies the assumptions and prior knowledge that are incorporated into NET-VISA's event determination. When NET-VISA is retrained, the IMV will be a visual tool for quality control both as a means of testing that the training has been accomplished correctly and that the IMS network has not changed unexpectedly. A preview of the IMV will be shown at this poster presentation. Homepage for the IMV IMV shows current model file and reference image.

  14. Supervisor's Interactive Model of Organizational Relationships

    Science.gov (United States)

    O'Reilly, Frances L.; Matt, John; McCaw, William P.

    2014-01-01

    The Supervisor's Interactive Model of Organizational Relationships (SIMOR) integrates two models addressed in the leadership literature and then highlights the importance of relationships. The Supervisor's Interactive Model of Organizational Relationships combines the modified Hersey and Blanchard model of situational leadership, the…

  15. Ocean-Glacier Interactions in Alaska and Comparison to Greenland

    Science.gov (United States)

    Motyka, R. J.; Truffer, M.

    2011-12-01

    Meltwater from Alaska's coastal glaciers and icefields accounts for nearly half of the total freshwater discharged into the Gulf of Alaska (GOA), with 10% coming from glacier volume loss associated with rapid thinning and retreat of glaciers (Neal et al, 2010). This glacier freshwater discharge contributes to maintaining the Alaska Coastal Current (ACC), which eventually reaches the Arctic Ocean (Royer and Grosch, 2006), thereby linking changes of glaciers along the coast of Alaska to the whole Arctic system. Water column temperatures on the shelf of northern GOA, monitored at buoy GAK1 near Seward, have increased by about 1 deg C since 1970 throughout the 250 m depth and vertical density stratification has also increased. Roughly half of the glacier contribution to ACC is derived from the ~ 50 tidewater glaciers (TWG) that drain from Alaska's coastal mountains into the Gulf of Alaska (GOA). Fjord systems link these TWGs to the GOA, with fjord circulation patterns driven in part by buoyancy-driven convection of subglacial freshwater discharge at the head of the fjord. Neoglacial shallow sills (deep) modulate the influx of warm ocean waters (up to 10 deg C) into these fjords. Convection of these warm waters melts icebergs and submerged faces of TWGs. The study of interactions between glaciers, fjords, and the ocean in coastal Alaska has had a long but very sporadic history. We examine this record starting with the "TWG cycle" hypothesis. We next examine recent hydrographic data from several different TWG fjords, representative of advancing and retreating TWGs (Columbia, Yahtse, Hubbard, and LeConte Glaciers), evaluate similarities and differences, and estimate the relative contributions of submarine glacier melting and subglacial discharge to fjord circulation. Circulation of warm ocean waters in fjords has also been hypothesized to play an important role in destabilizing and modulating glacier discharge from outlet glaciers in Greenland. We therefore compare

  16. Comparison of Statistical Models for Regional Crop Trial Analysis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qun-yuan; KONG Fan-ling

    2002-01-01

    Based on the review and comparison of main statistical analysis models for estimating varietyenvironment cell means in regional crop trials, a new statistical model, LR-PCA composite model was proposed, and the predictive precision of these models were compared by cross validation of an example data. Results showed that the order of model precision was LR-PCA model > AMMI model > PCA model > Treatment Means (TM) model > Linear Regression (LR) model > Additive Main Effects ANOVA model. The precision gain factor of LR-PCA model was 1.55, increasing by 8.4% compared with AMMI.

  17. A componential model of human interaction with graphs: 1. Linear regression modeling

    Science.gov (United States)

    Gillan, Douglas J.; Lewis, Robert

    1994-01-01

    Task analyses served as the basis for developing the Mixed Arithmetic-Perceptual (MA-P) model, which proposes (1) that people interacting with common graphs to answer common questions apply a set of component processes-searching for indicators, encoding the value of indicators, performing arithmetic operations on the values, making spatial comparisons among indicators, and repsonding; and (2) that the type of graph and user's task determine the combination and order of the components applied (i.e., the processing steps). Two experiments investigated the prediction that response time will be linearly related to the number of processing steps according to the MA-P model. Subjects used line graphs, scatter plots, and stacked bar graphs to answer comparison questions and questions requiring arithmetic calculations. A one-parameter version of the model (with equal weights for all components) and a two-parameter version (with different weights for arithmetic and nonarithmetic processes) accounted for 76%-85% of individual subjects' variance in response time and 61%-68% of the variance taken across all subjects. The discussion addresses possible modifications in the MA-P model, alternative models, and design implications from the MA-P model.

  18. Comparison of interactions between three food colorants and BSA.

    Science.gov (United States)

    Li, Tian; Cheng, Zhengjun; Cao, Lijun; Jiang, Xiaohui

    2016-03-01

    Fast Green FCF (FCF), Patent Blue V (PBV) and Acid Blue 1 (AB1) are used as food colorants. Multiple spectroscopic techniques were employed to probe in depth the affinity of FCF/PBV/AB1 with BSA in different pH and/or salt concentrations. The results showed that FCF/PBV/AB1 quenched the intrinsic fluorescence of BSA by a static process, and electrostatic force dominated the formation of BSA-FCF/PBV/AB1 complex which was confirmed by the effects of salt on their interactions. Subdomain IIA was the primary binding site for FCF/PBV/AB1 on BSA in the pH range of 5.5-7.4, while both Trp 212 and Trp 134 residues of BSA might be bound by FCF/PBV/AB1 at pH 4.8. The K values suggested that the binding ability of three food colorants with BSA was FCF>PBV>AB1. The results of UV-vis absorption, synchronous fluorescence, 3D fluorescence and FT-IR spectra proved that the structure of BSA altered by FCF/PBV/AB1.

  19. I-Interaction: An Intelligent In-Vehicle User Interaction Model

    CERN Document Server

    Liu, Li; 10.5121/iju.2010.1305

    2010-01-01

    The automobile is always a point of interest where new technology has been deployed. Because of this interest, human-vehicle interaction has been an appealing area for much research in recent years. The current in-vehicle design has been improved but still possesses some of the design from the traditional interaction style. In this paper, we propose a new user-oriented model for in-vehicle interaction model known as i-Interaction. The i-Interaction model provides user with an intuitive approach to interact with the In-Vehicle Information System (IVIS) by the keypad entry. It is the intent that the proposed usability testing for this model will help improve the way research and development is implemented from this topic. This model does not only provide the user with a direct interaction in vehicles but also introduce a new prospective that other research has not addressed.

  20. Performance Comparison of the European Storm Surge Models and Chaotic Model in Forecasting Extreme Storm Surges

    Science.gov (United States)

    Siek, M. B.; Solomatine, D. P.

    2009-04-01

    Storm surge modeling has rapidly developed considerably over the past 30 years. A number of significant advances on operational storm surge models have been implemented and tested, consisting of: refining computational grids, calibrating the model, using a better numerical scheme (i.e. more realistic model physics for air-sea interaction), implementing data assimilation and ensemble model forecasts. This paper addresses the performance comparison between the existing European storm surge models and the recently developed methods of nonlinear dynamics and chaos theory in forecasting storm surge dynamics. The chaotic model is built using adaptive local models based on the dynamical neighbours in the reconstructed phase space of observed time series data. The comparison focused on the model accuracy in forecasting a recently extreme storm surge in the North Sea on November 9th, 2007 that hit the coastlines of several European countries. The combination of a high tide, north-westerly winds exceeding 50 mph and low pressure produced an exceptional storm tide. The tidal level was exceeded 3 meters above normal sea levels. Flood warnings were issued for the east coast of Britain and the entire Dutch coast. The Maeslant barrier's two arc-shaped steel doors in the Europe's biggest port of Rotterdam was closed for the first time since its construction in 1997 due to this storm surge. In comparison to the chaotic model performance, the forecast data from several European physically-based storm surge models were provided from: BSH Germany, DMI Denmark, DNMI Norway, KNMI Netherlands and MUMM Belgium. The performance comparison was made over testing datasets for two periods/conditions: non-stormy period (1-Sep-2007 till 14-Oct-2007) and stormy period (15-Oct-2007 till 20-Nov-2007). A scalar chaotic model with optimized parameters was developed by utilizing an hourly training dataset of observations (11-Sep-2005 till 31-Aug-2007). The comparison results indicated the chaotic

  1. Atmospheric ionization induced by precipitating electrons: Comparison of CRAC:EPII model with a parametrization model

    Science.gov (United States)

    Artamonov, A. A.; Mishev, A. L.; Usoskin, I. G.

    2016-11-01

    Results of a comparison of a new model CRAC:EPII (Cosmic Ray Atmospheric Cascade: Electron Precipitation Induced Ionization) with a commonly used parametric model of atmospheric ionization is presented. The CRAC:EPII is based on a Monte Carlo simulation of precipitating electrons propagation and interaction with matter in the Earth's atmosphere. It explicitly considers energy deposit: ionization, pair production, Compton scattering, generation of Bremsstrahlung high energy photons, photo-ionization and annihilation of positrons, multiple scattering as physical processes accordingly. Propagation of precipitating electrons and their interactions with air is simulated with the GEANT4 simulation tool PLANETOCOSMICS code using NRLMSISE-00 atmospheric model. Ionization yields are computed and compared with a parametrization model for different energies of incident precipitating energetic electrons, using simulated fluxes of mono-energetic particles. A good agreement between the two models is achieved in the mesosphere but the contribution of Bremsstrahlung in the stratosphere, which is not accounted for in the parametric models, is found significant. As an example, we calculated profiles of the ion production rates in the middle and upper atmosphere (below 100 km) on the basis of balloon-born measured spectra of precipitating electrons for 30-October-2002 and 07-January-2004.

  2. Air-Sea interactions:Observations and models

    Science.gov (United States)

    Clayson, C. A.

    2014-12-01

    The interaction between the atmosphere and ocean consists of intense and episodic exchanges of heat, momentum, and moisture. However, the way in which these episodic events, and higher-scale frequency events in general, influence the coupled atmosphere/ocean system on longer time scales is not well understood. Models have predicted anthropogenic changes in the mean state and variability of various aspects of the climate which are closely tied to surface turbulent fluxes, but disagree on the nature of the changes. The competing influences of increased humidity, which should reduce fluxes, and increased wind speed and variability, which should increase fluxes, in determining the overall flux under a warming climate is not known. One motivating factor for this research is that there are enormous difficulties in understanding the coupled atmosphere-ocean system, given the complexity of two fluids with large-scale circulations that differ in time/space scales and are coupled through relatively small-scale surface fluxes and cloud processes. In order to make a tractable problem, such statistical techniques as joint distribution analysis, clustering, and variabilities of extremes in time and space must be used to simplify these complex relationships. In order to understand how the climate responds to variations in forcing, one necessary component is to understand the full distribution of variability of exchanges of heat and moisture between the atmosphere and ocean. A number of studies recognize the important role of surface heat and moisture fluxes in the generation and decay of important coupled air-sea phenomena. These mechanisms operate across a number of scales and contain significant contributions from interactions between the anomalous (i.e. non-mean), often extreme-valued, flux components. It is important to have a characterization and understanding of these processes for the development of accurate modeling efforts. In this talk I will make comparisons of some of

  3. Experimental and modeling evidence of appendicularian-ciliate interactions

    DEFF Research Database (Denmark)

    Lombard, Fabien; Eloire, Damien; Gobet, Angelique

    2010-01-01

    Interactions between appendicularians and ciliates were observed over the life span of Oikopleura dioica in laboratory cultures and clarified with the use of mathematical modeling and microscopic observations. Complex interactions including competition, parasitism, predation, and histophagy occur...

  4. Thole's interacting polarizability model in computational chemistry practice

    NARCIS (Netherlands)

    deVries, AH; vanDuijnen, PT; Zijlstra, RWJ; Swart, M

    1997-01-01

    Thole's interacting polarizability model to calculate molecular polarizabilities from interacting atomic polarizabilities is reviewed and its major applications in computational chemistry are illustrated. The applications include prediction of molecular polarizabilities, use in classical expressions

  5. Bulk viscous cosmological model with interacting dark fluids

    CERN Document Server

    Kremer, Gilberto M

    2012-01-01

    The objective of the present work is to study a cosmological model for a spatially flat Universe whose constituents are a dark energy field and a matter field which includes baryons and dark matter. The constituents are supposed to be in interaction and irreversible processes are taken into account through the inclusion of a non-equilibrium pressure. The non-equilibrium pressure is considered to be proportional to the Hubble parameter within the framework of a first order thermodynamic theory. The dark energy and matter fields are coupled by their barotropic indexes, which are considered as functions of the ratio between their energy densities. The free parameters of the model are adjusted from the best fits of the Hubble parameter data. A comparison of the viscous model with the non-viscous one is performed. It is shown that the equality of the dark energy and matter density parameters and the decelerated-accelerated transition occur at earlier times when the irreversible processes are present. Furthermore, ...

  6. Three-neutron resonance trajectories for realistic interaction models

    CERN Document Server

    Lazauskas, R

    2005-01-01

    Three-neutron resonances are searched using realistic nucleon-nucleon interaction models. Resonance pole trajectories were explored by artificially binding three-neutron and then gradually removing additional interaction. The final pole positions for three-neutron states up to $|J|$=5/2 finish in the fourth energy quadrant with Re(E)$\\leqslant0$ before additional interaction is removed. This study shows that realistic nucleon-nucleon interaction models exclude possible existence of observable three-neutron resonances.

  7. Are Noncovalent Interactions an Achilles Heel in Chemistry Education? A Comparison of Instructional Approaches

    Science.gov (United States)

    Williams, Leah C.; Underwood, Sonia M.; Klymkowsky, Michael W.; Cooper, Melanie M.

    2015-01-01

    Intermolecular forces (IMFs), or more broadly, noncovalent interactions either within or between molecules, are central to an understanding of a wide range of chemical and biological phenomena. In this study, we present a multiyear, multi-institutional, longitudinal comparison of how students enrolled in traditional general chemistry courses and…

  8. Functionalized anatomical models for EM-neuron Interaction modeling

    Science.gov (United States)

    Neufeld, Esra; Cassará, Antonino Mario; Montanaro, Hazael; Kuster, Niels; Kainz, Wolfgang

    2016-06-01

    The understanding of interactions between electromagnetic (EM) fields and nerves are crucial in contexts ranging from therapeutic neurostimulation to low frequency EM exposure safety. To properly consider the impact of in vivo induced field inhomogeneity on non-linear neuronal dynamics, coupled EM-neuronal dynamics modeling is required. For that purpose, novel functionalized computable human phantoms have been developed. Their implementation and the systematic verification of the integrated anisotropic quasi-static EM solver and neuronal dynamics modeling functionality, based on the method of manufactured solutions and numerical reference data, is described. Electric and magnetic stimulation of the ulnar and sciatic nerve were modeled to help understanding a range of controversial issues related to the magnitude and optimal determination of strength-duration (SD) time constants. The results indicate the importance of considering the stimulation-specific inhomogeneous field distributions (especially at tissue interfaces), realistic models of non-linear neuronal dynamics, very short pulses, and suitable SD extrapolation models. These results and the functionalized computable phantom will influence and support the development of safe and effective neuroprosthetic devices and novel electroceuticals. Furthermore they will assist the evaluation of existing low frequency exposure standards for the entire population under all exposure conditions.

  9. Structural Comparison of Different Antibodies Interacting with Parvovirus Capsids

    Energy Technology Data Exchange (ETDEWEB)

    Hafenstein, Susan; Bowman, Valorie D.; Sun, Tao; Nelson, Christian D.S.; Palermo, Laura M.; Chipman, Paul R.; Battisti, Anthony J.; Parrish, Colin R.; Rossmann, Michael G.; Cornell; Purdue

    2009-05-13

    The structures of canine parvovirus (CPV) and feline parvovirus (FPV) complexed with antibody fragments from eight different neutralizing monoclonal antibodies were determined by cryo-electron microscopy (cryoEM) reconstruction to resolutions varying from 8.5 to 18 {angstrom}. The crystal structure of one of the Fab molecules and the sequence of the variable domain for each of the Fab molecules have been determined. The structures of Fab fragments not determined crystallographically were predicted by homology modeling according to the amino acid sequence. Fitting of the Fab and virus structures into the cryoEM densities identified the footprints of each antibody on the viral surface. As anticipated from earlier analyses, the Fab binding sites are directed to two epitopes, A and B. The A site is on an exposed part of the surface near an icosahedral threefold axis, whereas the B site is about equidistant from the surrounding five-, three-, and twofold axes. One antibody directed to the A site binds CPV but not FPV. Two of the antibodies directed to the B site neutralize the virus as Fab fragments. The differences in antibody properties have been linked to the amino acids within the antibody footprints, the position of the binding site relative to the icosahedral symmetry elements, and the orientation of the Fab structure relative to the surface of the virus. Most of the exposed surface area was antigenic, although each of the antibodies had a common area of overlap that coincided with the positions of the previously mapped escape mutations.

  10. Interaction Strength and a Generalized Bak-Sneppen Evolution Model

    Institute of Scientific and Technical Information of China (English)

    李炜; 蔡勖

    2002-01-01

    The Bak-Sneppen evolution model is generalized in terms of a new concept and quantity: interaction strength.Based on a quantitative definition, the interaction strength describes the strength of the interaction between thenearest-neighbour individuals in the model Self-organized criticality is observed for the generalized model withten different values of interaction strength. The gap equation governing the self-organization is derived. It is alsofound that the self-organized threshold depends on the value of the interaction strength.

  11. Comparison of dark energy models after Planck 2015

    CERN Document Server

    Xu, Yue-Yao

    2016-01-01

    We make a comparison for ten typical, popular dark energy models according to theirs capabilities of fitting the current observational data. The observational data we use in this work include the JLA sample of type Ia supernovae observation, the Planck 2015 distance priors of cosmic microwave background observation, the baryon acoustic oscillations measurements, and the direct measurement of the Hubble constant. Since the models have different numbers of parameters, in order to make a fair comparison, we employ the Akaike and Bayesian information criteria to assess the worth of the models. The analysis results show that, according to the capability of explaining observations, the cosmological constant model is still the best one among all the dark energy models. The generalized Chaplygin gas model, the constant $w$ model, and the $\\alpha$ dark energy model are worse than the cosmological constant model, but still are good models compared to others. The holographic dark energy model, the new generalized Chaply...

  12. Tip studies using CFD and comparison with tip loss models

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver; Johansen, J.

    2004-01-01

    The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD......The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD...

  13. Off-site interaction effect in the Extended Hubbard Model with SCRPA method

    OpenAIRE

    Harir, S.; Bennai, M.; Boughaleb, Y.

    2009-01-01

    The Self Consistent Random Phase Approximation (SCRPA) and a Direct Analytical (DA) method are proposed to solve the Extended Hubbard Model in 1D. We have considered an Extended Hubbard Model (EHM) including on-site and off-site interactions for closed chains in one dimension with periodic boundary conditions. The comparison of the SCRPA results with ones obtained by a Direct Analytical approach shows that the SCRPA treats the problem of these closed chains with a rigorous manner. The analysi...

  14. String coupling and interactions in type IIB matrix model

    CERN Document Server

    Kitazawa, Yoshihisa

    2008-01-01

    We investigate the interactions of closed strings in IIB matrix model. The basic interaction of the closed superstring is realized by the recombination of two intersecting strings. Such interaction is investigated in IIB matrix model via two dimensional noncommutative gauge theory in the IR limit. By estimating the probability of the recombination, we identify the string coupling g_s in IIB matrix model. We confirm that our identification is consistent with matrix string theory.

  15. Identifying interacting pairs of sites in infinite range Ising models

    CERN Document Server

    Galves, Antonio; Takahashi, Daniel Yasumasa

    2010-01-01

    We consider Ising models (pairwise interaction Gibbs probability measures) in $\\Z^d$ with an infinite range potential. We address the problem of identifying pairs of interacting sites from a finite sample of independent realisations of the Ising model. The sample contains only the values assigned by the Ising model to a finite set of sites in $\\Z^d$. Our main result is an upperbound for the probability with our estimator to misidentify the pairs of interacting sites in this finite set.

  16. AISIM (Automated Interactive Simulation Modeling System) VAX Version Training Manual.

    Science.gov (United States)

    1985-02-01

    AD-Ri6t 436 AISIM (RUTOMATED INTERACTIVE SIMULATION MODELING 1/2 SYSTEM) VAX VERSION TRAI (U) HUGHES AIRCRAFT CO FULLERTON CA GROUND SYSTEMS GROUP S...Continue on reverse if necessary and Identify by block number) THIS DOCUMENT IS THE TRAINING MANUAL FOR THE AUTOMATED INTERACTIVE SIMULATION MODELING SYSTEM...form. Page 85 . . . . . . . . APPENDIX B SIMULATION REPORT FOR WORKING EXAMPLE Pa jPage.8 7AD-Ai6i 46 ISIM (AUTOMATED INTERACTIVE SIMULATION MODELING 2

  17. Nucleon-nucleon interactions in the double folding model for fusion reactions

    Institute of Scientific and Technical Information of China (English)

    Zhang Gao-Long; Liu Hao; Le Xiao-Yun

    2009-01-01

    Nucleus-nucleus potentials are determined in the framework of double folding model for M3Y-Reid and M3Y-Paris effective nucleon nucleon (NN) interactions. Both zero-range and finite-range exchange parts of NN interactions are considered in the folding procedure. In this paper the spherical projectile-spherical target system 16O+208Pb is selected for calculating the barrier energies, fusion cross sections and barrier distributions with the density-independent and density-dependcnt NN interactions on the basis of M3Y-Reid and M3Y-Paris NN interactions. The barrier energies become lower for Paris NN interactions in comparison with Reid NN interactions, and also for finite-range exchange part in comparison with zero-range exchange part. The density-dependent NN interactions give similar fusion cross sections and barrier distributions, and the density-independent NN interaction causes the barrier distribution moving to a higher position. However, the density-independent Reid NN interaction with zero-range exchange part gives the lowest fusion cross sections. We find that the calculated fusion cross sections and the barrier distributions are in agreement with the experimental data after rcnormalization of the nuclear potential due to coupled-channel effect.

  18. Some results regarding the comparison of the Earth's atmospheric models

    Directory of Open Access Journals (Sweden)

    Šegan S.

    2005-01-01

    Full Text Available In this paper we examine air densities derived from our realization of aeronomic atmosphere models based on accelerometer measurements from satellites in a low Earth's orbit (LEO. Using the adapted algorithms we derive comparison parameters. The first results concerning the adjustment of the aeronomic models to the total-density model are given.

  19. BMX bicycles: accident comparison with other models.

    OpenAIRE

    1985-01-01

    A comparison has been made between BMX bicycle accidents and those occurring when children ride other types of bicycle. The injuries sustained are compared to see if the clinical impressions that BMX are more dangerous, and produce more facial injuries, are correct. This was found not to be true as half the children involved rode BMX bicycles, and the injuries sustained were similar to those occurring to non BMX riders. BMX riders had a lower proportion of serious injuries than riders of raci...

  20. Comparison of performance of simulation models for floor heating

    DEFF Research Database (Denmark)

    Weitzmann, Peter; Svendsen, Svend

    2005-01-01

    only the floor construction, the differences can be directly compared. In this comparison, a two-dimensional model of a slab-on-grade floor including foundation is used as reference. The other models include a one-dimensional model and a thermal network model including the linear thermal transmittance......This paper describes the comparison of performance of simulation models for floor heating with different level of detail in the modelling process. The models are compared in an otherwise identical simulation model containing room model, walls, windows, ceiling and ventilation system. By exchanging...... of the foundation. The result can be also be found in the energy consumption of the building, since up to half the energy consumption is lost through the ground. Looking at the different implementations it is also found, that including a 1m ground volume below the floor construction under a one-dimensional model...

  1. 3D for Geosciences: Interactive Tangibles and Virtual Models

    Science.gov (United States)

    Pippin, J. E.; Matheney, M.; Kitsch, N.; Rosado, G.; Thompson, Z.; Pierce, S. A.

    2016-12-01

    Point cloud processing provides a method of studying and modelling geologic features relevant to geoscience systems and processes. Here, software including Skanect, MeshLab, Blender, PDAL, and PCL are used in conjunction with 3D scanning hardware, including a Structure scanner and a Kinect camera, to create and analyze point cloud images of small scale topography, karst features, tunnels, and structures at high resolution. This project successfully scanned internal karst features ranging from small stalactites to large rooms, as well as an external waterfall feature. For comparison purposes, multiple scans of the same object were merged into single object files both automatically, using commercial software, and manually using open source libraries and code. Files with format .ply were manually converted into numeric data sets to be analyzed for similar regions between files in order to match them together. We can assume a numeric process would be more powerful and efficient than the manual method, however it could lack other useful features that GUI's may have. The digital models have applications in mining as efficient means of replacing topography functions such as measuring distances and areas. Additionally, it is possible to make simulation models such as drilling templates and calculations related to 3D spaces. Advantages of using methods described here for these procedures include the relatively quick time to obtain data and the easy transport of the equipment. With regard to openpit mining, obtaining 3D images of large surfaces and with precision would be a high value tool by georeferencing scan data to interactive maps. The digital 3D images obtained from scans may be saved as printable files to create physical 3D-printable models to create tangible objects based on scientific information, as well as digital "worlds" able to be navigated virtually. The data, models, and algorithms explored here can be used to convey complex scientific ideas to a range of

  2. Second generation diffusion model of interacting gravity waves on the surface of deep fluid

    Directory of Open Access Journals (Sweden)

    A. Pushkarev

    2004-01-01

    Full Text Available We propose a second generation phenomenological model for nonlinear interaction of gravity waves on the surface of deep water. This model takes into account the effects of non-locality of the original Hasselmann diffusion equation still preserving important properties of the first generation model: physically consistent scaling, adherence to conservation laws and the existence of Kolmogorov-Zakharov solutions. Numerical comparison of both models with the original Hasselmann equation shows that the second generation models improves the angular distribution in the evolving wave energy spectrum.

  3. Comparison of Software Models for Energy Savings from Cool Roofs

    Energy Technology Data Exchange (ETDEWEB)

    New, Joshua Ryan [ORNL; Miller, William A [ORNL; Huang, Yu (Joe) [White Box Technologies; Levinson, Ronnen [Lawrence Berkeley National Laboratory (LBNL)

    2014-01-01

    A web-based Roof Savings Calculator (RSC) has been deployed for the United States Department of Energy as an industry-consensus tool to help building owners, manufacturers, distributors, contractors and researchers easily run complex roof and attic simulations. This tool employs modern web technologies, usability design, and national average defaults as an interface to annual simulations of hour-by-hour, whole-building performance using the world-class simulation tools DOE-2.1E and AtticSim in order to provide estimated annual energy and cost savings. In addition to cool reflective roofs, RSC simulates multiple roof and attic configurations including different roof slopes, above sheathing ventilation, radiant barriers, low-emittance roof surfaces, duct location, duct leakage rates, multiple substrate types, and insulation levels. A base case and energy-efficient alternative can be compared side-by-side to estimate monthly energy. RSC was benchmarked against field data from demonstration homes in Ft. Irwin, California; while cooling savings were similar, heating penalty varied significantly across different simulation engines. RSC results reduce cool roofing cost-effectiveness thus mitigating expected economic incentives for this countermeasure to the urban heat island effect. This paper consolidates comparison of RSC s projected energy savings to other simulation engines including DOE-2.1E, AtticSim, Micropas, and EnergyPlus, and presents preliminary analyses. RSC s algorithms for capturing radiant heat transfer and duct interaction in the attic assembly are considered major contributing factors to increased cooling savings and heating penalties. Comparison to previous simulation-based studies, analysis on the force multiplier of RSC cooling savings and heating penalties, the role of radiative heat exchange in an attic assembly, and changes made for increased accuracy of the duct model are included.

  4. Cosmic Ray Interaction Models: an Overview

    Directory of Open Access Journals (Sweden)

    Ostapchenko Sergey

    2016-01-01

    Full Text Available I review the state-of-the-art concerning the treatment of high energy cosmic ray interactions in the atmosphere, discussing in some detail the underlying physical concepts and the possibilities to constrain the latter by current and future measurements at the Large Hadron Collider. The relation of basic characteristics of hadronic interactions tothe properties of nuclear-electromagnetic cascades induced by primary cosmic rays in the atmosphere is addressed.

  5. I-Interaction: An Intelligent In-Vehicle User Interaction Model

    Directory of Open Access Journals (Sweden)

    Li Liu

    2010-07-01

    Full Text Available The automobile is always a point of interest where new technology has been deployed. Because of thisinterest, human-vehicle interaction has been an appealing area for much research in recent years. Thecurrent in-vehicle design has been improved but still possesses some of the design from the traditionalinteraction style. In this paper, we propose a new user-oriented model for in-vehicle interaction modelknown as i-Interaction. The i-Interaction model provides user with an intuitive approach to interact withthe In-Vehicle Information System (IVIS by the keypad entry. It is the intent that the proposed usabilitytesting for this model will help improve the way research and development is implemented from this topic.This model does not only provide the user with a direct interaction in vehicles but also introduce a newprospective that other research has not addressed.

  6. Model-driven design, refinement and transformation of abstract interactions

    NARCIS (Netherlands)

    Almeida, João Paolo A.; Dijkman, Remco; Ferreira Pires, Luis; Quartel, Dick; Sinderen, van Marten

    2006-01-01

    In a model-driven design process the interaction between application parts can be described at various levels of platform-independence. At the lowest level of platform-independence, interaction is realized by interaction mechanisms provided by specific middleware platforms. At higher levels of platf

  7. FROM A COMPARISON OF "TOP-DOWN" AND "BOTTOM-UP" APPROACHES TO THE APPLICATION OF THE "INTERACTIVE" APPROACH

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper introduces three models of reading. Then it ana-lyzes the data gathered from an experiment on the comparison ofthe "top.down" and the "bottom-up" approaches and accord-ingly draws the conclusion that the former approach is helpful inimproving students’ reading comprehension while the latter isuseful in developing their writing skills as well as their knowledgeof vocabulary and sentence structure. Finally this paper presentsa procedure of the application of the "interactive approach",which proves to be productive in teaching college English inten-sive reading.

  8. Investigation of Even-Even Ru Isotopes in Interacting Boson Model-2

    Institute of Scientific and Technical Information of China (English)

    A.H. Yilmaz; M. Kuruoglu

    2006-01-01

    The interacting boson model of Arima, Iachello, and co-workers is applied to the even ruthenium isotopes,96 Ru ~ 116Ru. Excitation energies, electromagnetic transition strengths, quadrupole and magnetic dipole moments, and △(E2/M1) mixing ratios have been described systematically. Mixed symmetry states are investigated. It is seen that the properties of low-lying levels in these isotopes, for which the comparison between experiment and theory is possible,can be satisfactorily characterized by the Interacting Boson Model-2.

  9. Radiation Belt Modeling for Spacecraft Design: Model Comparisons for Common Orbits

    Science.gov (United States)

    Lauenstein, J.-M.; Barth, J. L.

    2005-01-01

    We present the current status of radiation belt modeling, providing model details and comparisons with AP-8 and AE-8 for commonly used orbits. Improved modeling of the particle environment enables smarter space system design.

  10. Modelling microbial interactions and food structure in predictive microbiology

    NARCIS (Netherlands)

    Malakar, P.K.

    2002-01-01

    Keywords: modelling, dynamic models, microbial interactions, diffusion, microgradients, colony growth, predictive microbiology.

    Growth response of microorganisms in foods is a complex process. Innovations in food production and preservation techniques have resulted in adoption of

  11. The Interacting Boson Model for Anomalous Rotational Bands

    Institute of Scientific and Technical Information of China (English)

    QIANCheng-De; LIUDang-Bo; 等

    2002-01-01

    The interacting boson model for anomalous rotational bands is proposed.In the rotational SU(3) limit an asymptotic limit is discussed.Within the framework of the model several analytic relations for energies and electromagnetic transition rates are derived.

  12. Modelling microbial interactions and food structure in predictive microbiology

    NARCIS (Netherlands)

    Malakar, P.K.

    2002-01-01

    Keywords: modelling, dynamic models, microbial interactions, diffusion, microgradients, colony growth, predictive microbiology.    Growth response of microorganisms in foods is a complex process. Innovations in food production and preservation techniques have resulted in adoption of new technologies

  13. Comparison between two models of absorption of matter waves by a thin time-dependent barrier

    Science.gov (United States)

    Barbier, Maximilien; Beau, Mathieu; Goussev, Arseni

    2015-11-01

    We report a quantitative, analytical, and numerical comparison between two models of the interaction of a nonrelativistic quantum particle with a thin time-dependent absorbing barrier. The first model represents the barrier by a set of time-dependent discontinuous matching conditions, which are closely related to Kottler boundary conditions used in stationary-wave optics as a mathematical basis for Kirchhoff diffraction theory. The second model mimics the absorbing barrier with an off-diagonal δ potential with a time-dependent amplitude. We show that the two models of absorption agree in their predictions in a semiclassical regime, the regime readily accessible in modern experiments with ultracold atoms.

  14. Interacting boson models of nuclear and nucleon structure

    CERN Document Server

    Bijker, R

    1998-01-01

    Interacting boson models provide an elegant and powerful method to describe collective excitations of complex systems by introducing a set of effective degrees of freedom. We review the interacting boson model of nuclear structure and discuss a recent extension to the nucleon and its excited states.

  15. Models for the dynamics of interacting magnetic nanoparticles

    DEFF Research Database (Denmark)

    Hansen, Mikkel Fougt; Mørup, Steen

    1998-01-01

    A critical review of models for the dynamics of interacting magnetic nanoparticles is given. It is shown that the basic assumptions in the Dormann-Bessais-Fiorani model are unrealistic. The experimental observations on systems of interacting magnetic nanoparticles can, at least qualitatively...

  16. Data Analysis A Model Comparison Approach, Second Edition

    CERN Document Server

    Judd, Charles M; Ryan, Carey S

    2008-01-01

    This completely rewritten classic text features many new examples, insights and topics including mediational, categorical, and multilevel models. Substantially reorganized, this edition provides a briefer, more streamlined examination of data analysis. Noted for its model-comparison approach and unified framework based on the general linear model, the book provides readers with a greater understanding of a variety of statistical procedures. This consistent framework, including consistent vocabulary and notation, is used throughout to develop fewer but more powerful model building techniques. T

  17. Cyberpsychology: a human-interaction perspective based on cognitive modeling.

    Science.gov (United States)

    Emond, Bruno; West, Robert L

    2003-10-01

    This paper argues for the relevance of cognitive modeling and cognitive architectures to cyberpsychology. From a human-computer interaction point of view, cognitive modeling can have benefits both for theory and model building, and for the design and evaluation of sociotechnical systems usability. Cognitive modeling research applied to human-computer interaction has two complimentary objectives: (1) to develop theories and computational models of human interactive behavior with information and collaborative technologies, and (2) to use the computational models as building blocks for the design, implementation, and evaluation of interactive technologies. From the perspective of building theories and models, cognitive modeling offers the possibility to anchor cyberpsychology theories and models into cognitive architectures. From the perspective of the design and evaluation of socio-technical systems, cognitive models can provide the basis for simulated users, which can play an important role in usability testing. As an example of application of cognitive modeling to technology design, the paper presents a simulation of interactive behavior with five different adaptive menu algorithms: random, fixed, stacked, frequency based, and activation based. Results of the simulation indicate that fixed menu positions seem to offer the best support for classification like tasks such as filing e-mails. This research is part of the Human-Computer Interaction, and the Broadband Visual Communication research programs at the National Research Council of Canada, in collaboration with the Carleton Cognitive Modeling Lab at Carleton University.

  18. Comparison of sparse point distribution models

    DEFF Research Database (Denmark)

    Erbou, Søren Gylling Hemmingsen; Vester-Christensen, Martin; Larsen, Rasmus;

    2010-01-01

    This paper compares several methods for obtaining sparse and compact point distribution models suited for data sets containing many variables. These are evaluated on a database consisting of 3D surfaces of a section of the pelvic bone obtained from CT scans of 33 porcine carcasses. The superior...... model w.r.t. sparsity, reconstruction error and interpretability is found to be a varimax rotated model with a threshold applied to small loadings. The models describe the biological variation in the database and is used for developing robotic tools when automating labor intensive procedures...

  19. Bistatic Reverberation in Shallow Water: Modelling and Data Comparison

    Institute of Scientific and Technical Information of China (English)

    李风华; 刘建军

    2002-01-01

    Bistatic and monostatic reverberation data were recorded in the 2001 Asian Sea International Acoustic Experiment (ASIAEX). A model based on the normal mode theory has been developed to calculate bistatic bottom reverberation in shallow water and to explain the recorded data. The comparisons between the monostatic and bistatic reverberation data are discussed, and the comparisons between model predictions and measured bistatic reverberation data are also presented. The numerical and experimental results show that the numericalpredictions from the bistatic reverberation model fit the experimental data well, and the long-range bistatic reverberation with a time delay can be approximately expressed by the monostatic reverberation data.

  20. CHOREO: An Interactive Computer Model for Dance.

    Science.gov (United States)

    Savage, G. J.; Officer, J. M.

    1978-01-01

    Establishes the need for literacy in dance; and describes two dance notation systems: the Massine notation method, and the Labanotation method. The use of interactive computer graphics as a tool for both learning and interpreting dance notation is introduced. (Author/VT)

  1. A Method for Model Checking Feature Interactions

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Le Guilly, Thibaut; Ravn, Anders Peter

    2015-01-01

    This paper presents a method to check for feature interactions in a system assembled from independently developed concurrent processes as found in many reactive systems. The method combines and refines existing definitions and adds a set of activities. The activities describe how to populate the ...

  2. Amorphous track models: a numerical comparison study

    DEFF Research Database (Denmark)

    Greilich, Steffen; Grzanka, Leszek; Hahn, Ute;

    Amorphous track models such as Katz' Ion-Gamma-Kill (IGK) approach [1, 2] or the Local Effect Model (LEM) [3, 4] had reasonable success in predicting the response of solid state dosimeters and radiobiological systems. LEM is currently applied in radiotherapy for biological dose optimization in ca...

  3. Amorphous track models: A numerical comparison study

    DEFF Research Database (Denmark)

    Greilich, Steffen; Grzanka, L.; Bassler, N.;

    2010-01-01

    We present an open-source code library for amorphous track modelling which is suppose to faciliate the application and numerical comparability as well as serve as a frame-work for the implementation of new models. We show an example of using the library indicating the choice of submodels has a si...

  4. Numerical Modeling of Water Wave Interaction with A Soft Mud Bed

    Institute of Scientific and Technical Information of China (English)

    齐鹏; 王石青; 侯一筠

    2004-01-01

    A vertical 2-D numerical model is presented for simulating the interaction between water waves and a soft mud bed.Taking into account nonlinear rheology, a semi-empirical rheological model is applied to this water-mud model, reflecting the combined viseo-elasto-plastic properties of soft mud under such oscillatory external forces as water waves. In order to increase the resolution of the flow in the neighborhood of both sides of the inter-surface, a logarithmic grid in the vertical direction is employed for numerical treatment. Model verifications are given through comparisons between the calculated and the measured mud mass transport velocities as well as wave height changes.

  5. Dynamic energy-demand models. A comparison

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Feng [Department of Economics, Goeteborg University, Gothenburg (Sweden)

    2000-04-01

    This paper compares two second-generation dynamic energy demand models, a translog (TL) and a general Leontief (GL), in the study of price elasticities and factor substitutions of nine Swedish manufacturing industries: food, textiles, wood, paper, printing, chemicals, non-metallic minerals, base metals and machinery. Several model specifications are tested with likelihood ratio test. There is a disagreement on short-run adjustments; the TL model accepts putty-putty production technology of immediate adjustments, implying equal short- and long-run price elasticities of factors, while the GL model rejects immediate adjustments, giving out short-run elasticities quite different from the long-run. The two models also disagree in substitutability in many cases. 21 refs.

  6. Yukawa Interaction from a SUSY Composite Model

    CERN Document Server

    Haba, N

    1998-01-01

    We present a composite model that is based on non-perturbative effects of N=1 supersymmetric SU(N_C) gauge theory with N_f=N_C+1 flavors. In this model, we consider N_C=7, where all matter fields in the supersymmetric standard model, that is, quarks, leptons and Higgs particles are bound states of preons and anti-preons. When SU(7)_H hyper-color coupling becomes strong, Yukawa couplings of quarks and leptons are generated dynamically. We show one generation model at first, and next we show models of three generations.

  7. Social interactions model and adaptability of human behavior

    Directory of Open Access Journals (Sweden)

    Kun eZhao

    2011-12-01

    Full Text Available Human social networks evolve on the fast timescale of face-to face interactions and of interactions mediated by technology such as a telephone calls or video conferences. The resulting networks have a strong dynamical component that changes significantly the properties of dynamical processes. In this paper we study a general model of pairwise human social interaction intended to model both face-to face interactions and mobile phone communication. We study the distribution of durations of social interactions in whitin the model. This distribution in one limit is a power law, for other values of the parameters of the model this distribution is given by a Weibull function. Therefore the model can be used to model both face-to-face interactions data, where the distribution of duration has been shown to be fat-tailed, and mobile phone communication data where the distribution of duration is given by a Weibull distribution.The highly adaptable social interaction model propose in this paper has a very simple algorithmic implementation and can be used to simulate dynamical processes occurring in dynamical social interaction networks.

  8. A Model for Molten Fuel-Coolant Interaction during Melt Slumping in a Nuclear Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sohal, Manohar Singh; Siefken, Larry James

    1999-10-01

    This paper describes a simple fuel melt slumping model to replace the current parametric model in SCDAP/RELAP5. Specifically, a fuel-coolant interaction (FCI) model is developed to analyze the slumping molten fuel, molten fuel breakup, heat transfer to coolant, relocation of the molten droplets, size of a partially solidified particles that settle to the bottom of the lower plenum, and melt-plenum interaction, if any. Considering our objectives, the molten fuel jet breakup model, and fuel droplets Lagrangian model as included in a code TEXAS-V with Eulerian thermal hydraulics for water and steam from SCDAP/RELAP5 were used. The model was assessed with experimental data from MAGICO-2000 tests performed at University of California at Santa Barbara, and FARO Test L-08 performed at Joint Research Center, Ispra, Italy. The comparison was found satisfactory.

  9. Quantitative comparisons of satellite observations and cloud models

    Science.gov (United States)

    Wang, Fang

    Microwave radiation interacts directly with precipitating particles and can therefore be used to compare microphysical properties found in models with those found in nature. Lower frequencies (minimization procedures but produce different CWP and RWP. The similarity in Tb can be attributed to comparable Total Water Path (TWP) between the two retrievals while the disagreement in the microphysics is caused by their different degrees of constraint of the cloud/rain ratio by the observations. This situation occurs frequently and takes up 46.9% in the one month 1D-Var retrievals examined. To attain better constrained cloud/rain ratios and improved retrieval quality, this study suggests the implementation of higher microwave frequency channels in the 1D-Var algorithm. Cloud Resolving Models (CRMs) offer an important pathway to interpret satellite observations of microphysical properties of storms. High frequency microwave brightness temperatures (Tbs) respond to precipitating-sized ice particles and can, therefore, be compared with simulated Tbs at the same frequencies. By clustering the Tb vectors at these frequencies, the scene can be classified into distinct microphysical regimes, in other words, cloud types. The properties for each cloud type in the simulated scene are compared to those in the observation scene to identify the discrepancies in microphysics within that cloud type. A convective storm over the Amazon observed by the Tropical Rainfall Measuring Mission (TRMM) is simulated using the Regional Atmospheric Modeling System (RAMS) in a semi-ideal setting, and four regimes are defined within the scene using cluster analysis: the 'clear sky/thin cirrus' cluster, the 'cloudy' cluster, the 'stratiform anvil' cluster and the 'convective' cluster. The relationship between Tb difference of 37 and 85 GHz and Tb at 85 GHz is found to contain important information of microphysical properties such as hydrometeor species and size distributions. Cluster

  10. Testing for gene-gene interaction with AMMI models.

    Science.gov (United States)

    Barhdadi, Amina; Dubé, Marie-Pierre

    2010-01-01

    Studies have shown that many common diseases are influenced by multiple genes and their interactions. There is currently a strong interest in testing for association between combinations of these genes and disease, in particular because genes that affect the risk of disease only in the presence of another genetic variant may not be detected in marginal analysis. In this paper we propose the use of additive main effect and multiplicative interaction (AMMI) models to detect and to quantify gene-gene interaction effects for a quantitative trait. The objective of the present research is to demonstrate the practical advantages of these models to describe complex interaction between two unlinked loci. Although gene-gene interactions have often been defined as a deviance from additive genetic effects, the residual term has generally not been appropriately treated. The AMMI models allow for the analysis of a two way factorial data structure and combine the analysis of variance of the two main genotype effects with a principal component analysis of the residual multiplicative interaction. The AMMI models for gene-gene interaction presented here allow for the testing of non additivity between the two loci, and also describe how their interaction structure fits the existing non-additivity. Moreover, these models can be used to identify the specific two genotypes combinations that contribute to the significant gene-gene interaction. We describe the use of the biplot to display the structure of the interaction and evaluate the performance of the AMMI and the special cases of the AMMI previously described by Tukey and Mandel with simulated data sets. Our simulated study showed that the AMMI model is as powerful as general linear models when the interaction is not modeled in the presence of marginal effects. However, in the presence of pure epitasis, i.e. in the absence of marginal effects, the AMMI method was not found to be superior to other tested regression methods.

  11. Comparison of cursive models for handwriting instruction.

    Science.gov (United States)

    Karlsdottir, R

    1997-12-01

    The efficiency of four different cursive handwriting styles as model alphabets for handwriting instruction of primary school children was compared in a cross-sectional field experiment from Grade 3 to 6 in terms of the average handwriting speed developed by the children and the average rate of convergence of the children's handwriting to the style of their model. It was concluded that styles with regular entry stroke patterns give the steadiest rate of convergence to the model and styles with short ascenders and descenders and strokes with not too high curvatures give the highest handwriting speed.

  12. Comparison of dogs and humans in visual scanning of social interaction

    OpenAIRE

    Törnqvist, Heini; Somppi, Sanni; Koskela, Aija; Krause, Christina M.; Vainio, Outi; Kujala, Miiamaaria V.

    2015-01-01

    Previous studies have demonstrated similarities in gazing behaviour of dogs and humans, but comparisons under similar conditions are rare, and little is known about dogs' visual attention to social scenes. Here, we recorded the eye gaze of dogs while they viewed images containing two humans or dogs either interacting socially or facing away: the results were compared with equivalent data measured from humans. Furthermore, we compared the gazing behaviour of two dog and two human populations w...

  13. A new interaction potential for swarming models

    CERN Document Server

    Carrillo, J A; Panferov, V

    2012-01-01

    We consider a self-propelled particle system which has been used to describe certain types of collective motion of animals, such as fish schools and bird flocks. Interactions between particles are specified by means of a pairwise potential, repulsive at short ranges and attractive at longer ranges. The exponentially decaying Morse potential is a typical choice, and is known to reproduce certain types of collective motion observed in nature, particularly aligned flocks and rotating mills. We introduce a class of interaction potentials, that we call Quasi-Morse, for which flock and rotating mills states are also observed numerically, however in that case the corresponding macroscopic equations allow for explicit solutions in terms of special functions, with coefficients that can be obtained numerically without solving the particle evolution. We compare thus obtained solutions with long-time dynamics of the particle systems and find a close agreement for several types of flock and mill solutions.

  14. A new interaction potential for swarming models

    Science.gov (United States)

    Carrillo, J. A.; Martin, S.; Panferov, V.

    2013-10-01

    We consider a self-propelled particle system which has been used to describe certain types of collective motion of animals, such as fish schools and bird flocks. Interactions between particles are specified by means of a pairwise potential, repulsive at short ranges and attractive at longer ranges. The exponentially decaying Morse potential is a typical choice, and is known to reproduce certain types of collective motion observed in nature, particularly aligned flocks and rotating mills. We introduce a class of interaction potentials, that we call Quasi-Morse, for which flock and rotating mills states are also observed numerically, however in that case the corresponding macroscopic equations allow for explicit solutions in terms of special functions, with coefficients that can be obtained numerically without solving the particle evolution. We compare the obtained solutions with long-time dynamics of the particle systems and find a close agreement for several types of flock and mill solutions.

  15. Internal kinematics of modelled interacting disc galaxies

    CERN Document Server

    Kronberger, T; Schindler, S; Böhm, A; Kutdemir, E; Ziegler, B L

    2006-01-01

    We present an investigation of galaxy-galaxy interactions and their effects on the velocity fields of disc galaxies in combined N-body/hydrodynamic simulations, which include cooling, star formation with feedback, and galactic winds. Rotation curves (RCs) of the gas are extracted from these simulations in a way that follows the procedure applied in observations of distant, small, and faint galaxies as closely as possible. We show that galaxy-galaxy mergers and fly-bys significantly disturb the velocity fields and hence the RCs of the interacting galaxies, leading to asymmetries and distortions in the RCs. Typical features of disturbed kinematics are rising or falling profiles in direction to the companion galaxy and bumps in the RCs. In addition, tidal tails can leave strong imprints on the rotation curve. All these features are observable for intermediate redshift galaxies, on which we focus our investigations. The appearance of these distortions depends, however, strongly on the viewing angle. The velocity ...

  16. A forecast comparison of volatility models

    DEFF Research Database (Denmark)

    Hansen, Peter Reinhard; Lunde, Asger

    2005-01-01

    We compare 330 ARCH-type models in terms of their ability to describe the conditional variance. The models are compared out-of-sample using DM-$ exchange rate data and IBM return data, where the latter is based on a new data set of realized variance. We find no evidence that a GARCH(1,1) is outpe......We compare 330 ARCH-type models in terms of their ability to describe the conditional variance. The models are compared out-of-sample using DM-$ exchange rate data and IBM return data, where the latter is based on a new data set of realized variance. We find no evidence that a GARCH(1...

  17. Interactions between riluzole and conventional antiepileptic drugs -- a comparison of results obtained in the subthreshold method and isobolographic analysis.

    Science.gov (United States)

    Borowicz, K K; Rwiader, M; Drelewska, E; Czuczwar, S J

    2004-12-01

    The exact types of pharmacodynamic interactions between riluzole and conventional antiepileptic drugs were evaluated in two available ways, the subthreshold and isobolographic analysis. Maximal electroshock test in mice was used as an animal model for generalized tonic-clonic convulsions. In the first method, riluzole (1.25-2.5 mg/kg) significantly raised the electroconvulsive threshold in mice. The drug administered at its subprotective dose of 0.3125 mg/kg enhanced the antiseizure activity of carbamazepine and phenobarbital, while, when applied at the higher dose of 0.625 mg/kg, it potentiated also the action of valproate and diphenylhydantoin. Riluzole (0.625) alone and in combinations with antiepileptic drugs did not produced any motor or log-term memory deficit. Results obtained from isobolographic analysis determined pure additive interaction between riluzole and all used conventional antiepileptic drugs. Since riluzole did not change plasma concentrations of co-administered antiepileptics, pharmacokinetic interactions, at least in terms of their free plasma levels, do not seem probable. The results of the present study confirm significant antiseizure properties of riluzole in the model of generalized tonic-clonic epileptic attacks. Moreover, comparison of effects obtained from both methods evaluating drug interactions strongly indicates a crucial role of the isobolographic analysis in verification and supplementation data achieved from the subthreshold method.

  18. Point Process Modeling for Directed Interaction Networks

    Science.gov (United States)

    2011-10-01

    Enron corporation between 1998 and 2002. These e-mail interaction data give rise to the following questions: Homophily To what extent are traits shared...methods Our example analysis uses publicly available data from the Enron e-mail corpus (Cohen, 2009), a large subset of the e-mail messages sent within...the Enron corporation between 1998 and 2002, and made public as the result of a subpoena by the U.S. Federal Energy Regulatory Commission during an

  19. Effective models for interacting quarks from QCD

    Energy Technology Data Exchange (ETDEWEB)

    Braghin, Fabio L. [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Inst. de Fisica

    2012-07-01

    Full text: In this work the Quantum Chromodynamics ( QCD ) path integral is considered with the introduction of auxiliary variables for composite gluon fields. One of these variables eventually leads to the gluon condensates of order 2 and another one corresponds to an anti - symmetric composite gluon configuration. Gluon degrees of freedom, and part of the quark degrees of freedom, are integrated out and two different limits of the resulting effective quark interactions are analysed. (author)

  20. Comparison of dark energy models after Planck 2015

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yue-Yao [Northeastern University, Department of Physics, College of Sciences, Shenyang (China); Zhang, Xin [Northeastern University, Department of Physics, College of Sciences, Shenyang (China); Peking University, Center for High Energy Physics, Beijing (China)

    2016-11-15

    We make a comparison for ten typical, popular dark energy models according to their capabilities of fitting the current observational data. The observational data we use in this work include the JLA sample of type Ia supernovae observation, the Planck 2015 distance priors of cosmic microwave background observation, the baryon acoustic oscillations measurements, and the direct measurement of the Hubble constant. Since the models have different numbers of parameters, in order to make a fair comparison, we employ the Akaike and Bayesian information criteria to assess the worth of the models. The analysis results show that, according to the capability of explaining observations, the cosmological constant model is still the best one among all the dark energy models. The generalized Chaplygin gas model, the constant w model, and the α dark energy model are worse than the cosmological constant model, but still are good models compared to others. The holographic dark energy model, the new generalized Chaplygin gas model, and the Chevalliear-Polarski-Linder model can still fit the current observations well, but from an economically feasible perspective, they are not so good. The new agegraphic dark energy model, the Dvali-Gabadadze-Porrati model, and the Ricci dark energy model are excluded by the current observations. (orig.)

  1. Comparison of dark energy models after Planck 2015

    Science.gov (United States)

    Xu, Yue-Yao; Zhang, Xin

    2016-11-01

    We make a comparison for ten typical, popular dark energy models according to their capabilities of fitting the current observational data. The observational data we use in this work include the JLA sample of type Ia supernovae observation, the Planck 2015 distance priors of cosmic microwave background observation, the baryon acoustic oscillations measurements, and the direct measurement of the Hubble constant. Since the models have different numbers of parameters, in order to make a fair comparison, we employ the Akaike and Bayesian information criteria to assess the worth of the models. The analysis results show that, according to the capability of explaining observations, the cosmological constant model is still the best one among all the dark energy models. The generalized Chaplygin gas model, the constant w model, and the α dark energy model are worse than the cosmological constant model, but still are good models compared to others. The holographic dark energy model, the new generalized Chaplygin gas model, and the Chevalliear-Polarski-Linder model can still fit the current observations well, but from an economically feasible perspective, they are not so good. The new agegraphic dark energy model, the Dvali-Gabadadze-Porrati model, and the Ricci dark energy model are excluded by the current observations.

  2. Five challenges in modelling interacting strain dynamics

    DEFF Research Database (Denmark)

    Wikramaratna, Paul S; Kurcharski, Adam; Gupta, Sunetra

    2015-01-01

    Population epidemiological models where hosts can be infected sequentially by different strains have the potential to help us understand many important diseases. Researchers have in recent years started to develop and use such models, but the extra layer of complexity from multiple strains brings...... with it many technical challenges. It is therefore hard to build models which have realistic assumptions yet are tractable. Here we outline some of the main challenges in this area. First we begin with the fundamental question of how to translate from complex small-scale dynamics within a host to useful...... population models. Next we consider the nature of so-called “strain space”. We describe two key types of host heterogeneities, and explain how models could help generate a better understanding of their effects. Finally, for diseases with many strains, we consider the challenge of modelling how immunity...

  3. A Model of Elementary Particle Interactions

    CERN Document Server

    Khan, I

    2000-01-01

    There is a second kind of light which does not interact with our electrons. However it interacts with some of our protons (p) and some of our neutrons (n) which are both of two kinds: protons (p, p`), neutrons (n`, n) differing in the two kinds of charges (Q1, Q2) associated with the two kinds of light. p [p`] and n` [n] have (Q1, Q2) values equal to (1, 1) [(1, 0)] and (0, 0) [(0, 1)] respectively. There is also a second kind of electron (Q2 =1, Q1= 0), equal in mass to our electron (Q1 = -1, Q2= 0), which does not interact with our (the first) kind of light. Three major scenarios S1, S2 and X4 arise. In S1, matter in the solar system on large scales is predominantly neutralized in both kinds of charges and the weak forces of attraction among the sun and planets are due to a fundamental force of nature. However in this scenario we must postulate that human consciousness is locked on to chemical reactions in the retina involving the first kind of light and the first kind of electrons only. It is oblivious to ...

  4. Bayesian comparisons of codon substitution models.

    Science.gov (United States)

    Rodrigue, Nicolas; Lartillot, Nicolas; Philippe, Hervé

    2008-11-01

    In 1994, Muse and Gaut (MG) and Goldman and Yang (GY) proposed evolutionary models that recognize the coding structure of the nucleotide sequences under study, by defining a Markovian substitution process with a state space consisting of the 61 sense codons (assuming the universal genetic code). Several variations and extensions to their models have since been proposed, but no general and flexible framework for contrasting the relative performance of alternative approaches has yet been applied. Here, we compute Bayes factors to evaluate the relative merit of several MG and GY styles of codon substitution models, including recent extensions acknowledging heterogeneous nonsynonymous rates across sites, as well as selective effects inducing uneven amino acid or codon preferences. Our results on three real data sets support a logical model construction following the MG formulation, allowing for a flexible account of global amino acid or codon preferences, while maintaining distinct parameters governing overall nucleotide propensities. Through posterior predictive checks, we highlight the importance of such a parameterization. Altogether, the framework presented here suggests a broad modeling project in the MG style, stressing the importance of combining and contrasting available model formulations and grounding developments in a sound probabilistic paradigm.

  5. Mathematical Modeling of Circadian and Homeostatic Interaction

    Science.gov (United States)

    2011-11-16

    Williams and C. Diniz Behn. A Hodgkin- Huxley -type model orexin neuron. SLEEP 32, A25, 2009. 4) C. Diniz Behn, D. Pal, G. Vanini, R. Lydic, G. A. Mashour...Switzerland, September 2009. 11) K. Williams, “A Hodgkin- Huxley -type model orexin neuron”, Associated Professional Sleep Societies Annual Meeting...Seattle, WA, June 2009. 12) K. Williams, “Dynamics in a Hodgkin- Huxley -type model orexin neuron”, Society for Industrial and Applied Mathematics Annual

  6. Comparison of the precision of three commonly used GPS models

    Directory of Open Access Journals (Sweden)

    E Chavoshi

    2016-04-01

    View software (v3.3 was used (Fig.3. The real location of stations and registered by each receiver position has been determined. Information recorded in Map Source software, including all longitude and latitudes registered for each station and receiver were transferred to Excel Software (2007. Table 2 shows the mean precision values recorded in each weather conditions. The results obtained by equation 1 (the mean error at each station showed that the GPS MAP 78s model has the lowest error of 91 cm, VISTA eTrex model has a maximum error of 4.7 meters and MAP 60 csx model has mean error of about 2.64 meters. The analysis of variance of models and weather conditions and the time of day with the interactions between factors have been shown in Table 3. Results showed that there is significant difference (0.01

    models, but there is no significant difference between the date and time positioning precision of different receivers models. Investigating of the interactions between the receiver models and the weather conditions showed no significant effect of them and the interaction between the receiver models and the measured time difference is not significant. These results showed that weather conditions and time of day is the same effect on positioning precision of GPS receivers used in this research. These results were consistent with the study of Jose and colleagues (Jose et al., 2006. The mean Comparison test of LSD (at 5% level for the accuracy and precision of the models showed the significant difference for all models (Table 4. Figures 4 and 5 respectively show the accuracy and precision of three models of GPS receiver at different times of day and different weather conditions. Conclusions: Effect of daylight hours on positioning precision was very low; also the effect of different weather conditions may reduce the accuracy of GPS positioning to size of few centimeters. Overall, the results indicated that between the three factors include the models, the effects

  7. Comparison of the precision of three commonly used GPS models

    Directory of Open Access Journals (Sweden)

    E Chavoshi

    2016-04-01

    View software (v3.3 was used (Fig.3. The real location of stations and registered by each receiver position has been determined. Information recorded in Map Source software, including all longitude and latitudes registered for each station and receiver were transferred to Excel Software (2007. Table 2 shows the mean precision values recorded in each weather conditions. The results obtained by equation 1 (the mean error at each station showed that the GPS MAP 78s model has the lowest error of 91 cm, VISTA eTrex model has a maximum error of 4.7 meters and MAP 60 csx model has mean error of about 2.64 meters. The analysis of variance of models and weather conditions and the time of day with the interactions between factors have been shown in Table 3. Results showed that there is significant difference (0.01

    models, but there is no significant difference between the date and time positioning precision of different receivers models. Investigating of the interactions between the receiver models and the weather conditions showed no significant effect of them and the interaction between the receiver models and the measured time difference is not significant. These results showed that weather conditions and time of day is the same effect on positioning precision of GPS receivers used in this research. These results were consistent with the study of Jose and colleagues (Jose et al., 2006. The mean Comparison test of LSD (at 5% level for the accuracy and precision of the models showed the significant difference for all models (Table 4. Figures 4 and 5 respectively show the accuracy and precision of three models of GPS receiver at different times of day and different weather conditions. Conclusions: Effect of daylight hours on positioning precision was very low; also the effect of different weather conditions may reduce the accuracy of GPS positioning to size of few centimeters. Overall, the results indicated that between the three factors include the models, the effects

  8. Comparison Of Arrival Models In The Context Of Urban Transport

    Directory of Open Access Journals (Sweden)

    Endri Raço

    2012-06-01

    Full Text Available The process of modeling a random process requires a careful analysis and a correct interpretation of the behavior of the process. In different contexts, different statistical distributions may be eligible for the same model obtained in the study. In response to this situation created quite often in practice, we make use of statistical analysis methods to make possible comparison and decision making regarding the selection of the most appropriate model. In our study the usage of such methods is illustrated by comparing two of models commonly mentioned in literature when it comes to bus headway times modeling. Models under consideration are Gaussian model and Poisson model. To evaluate the performance of these models visual and analytical methods are used in this study. The simulation of these processes is made possible using the power of R language. Although both models have their practicability in a certain degree, tests showed that the Gaussian model fits best with the real model

  9. Cosmological models with interacting components and mass-varying neutrinos

    CERN Document Server

    Collodel, Lucas G

    2012-01-01

    A model for a homogeneous and isotropic spatially flat Universe, composed of baryons, radiation, neutrinos, dark matter and dark energy is analyzed. We infer that dark energy (considered to behave as a scalar field) interacts with dark matter (either by the Wetterich model, or by the Anderson and Carroll model) and with neutrinos by a model proposed by Brookfield et al.. The latter is understood to have a mass-varying behavior. We show that for a very-softly varying field, both interacting models for dark matter give the same results. The models reproduce the expected red-shift performances of the present behavior of the Universe.

  10. Hospital Case Cost Estimates Modelling - Algorithm Comparison

    CERN Document Server

    Andru, Peter

    2008-01-01

    Ontario (Canada) Health System stakeholders support the idea and necessity of the integrated source of data that would include both clinical (e.g. diagnosis, intervention, length of stay, case mix group) and financial (e.g. cost per weighted case, cost per diem) characteristics of the Ontario healthcare system activities at the patient-specific level. At present, the actual patient-level case costs in the explicit form are not available in the financial databases for all hospitals. The goal of this research effort is to develop financial models that will assign each clinical case in the patient-specific data warehouse a dollar value, representing the cost incurred by the Ontario health care facility which treated the patient. Five mathematical models have been developed and verified using real dataset. All models can be classified into two groups based on their underlying method: 1. Models based on using relative intensity weights of the cases, and 2. Models based on using cost per diem.

  11. Mathematical Modelling of Laser/Material Interactions.

    Science.gov (United States)

    1983-11-25

    translated to the model input. Even an experimental mode print can also be digitalised for the model. In trying to describe high order modes matliematically...4. Mazumder J. Steen W.M. "Welding of Ti 6al - 4V by continuous wave CO2 laser". Metal construction Sept. 1980 pp423 - 427. 5. Kogelnik H, Li.T Proc

  12. Visualizing the impact of art: An update and comparison of current psychological models of art experience

    Directory of Open Access Journals (Sweden)

    Matthew ePelowski

    2016-04-01

    Full Text Available The last decade has witnessed a renaissance of empirical and psychological approaches to art study, especially regarding cognitive models of art processing experience. This new emphasis on modeling has often become the basis for our theoretical understanding of human interaction with art. Models also often define areas of focus and hypotheses for new empirical research, and are increasingly important for connecting psychological theory to discussions of the brain. However, models are often made by different researchers, with quite different emphases or visual styles. Inputs and psychological outcomes may be differently considered, or can be under-reported with regards to key functional components. Thus, we may lose the major theoretical improvements and ability for comparison that can be had with models. To begin addressing this, this paper presents a theoretical assessment, comparison, and new articulation of a selection of key contemporary cognitive or information-processing-based approaches detailing the mechanisms underlying the viewing of art. We review six major models in contemporary psychological aesthetics. We in turn present redesigns of these models using a unified visual form, in some cases making additions or creating new models where none had previously existed. We also frame these approaches in respect to their targeted outputs (e.g., emotion, appraisal, physiological reaction and their strengths within a more general framework of early, intermediate and later processing stages. This is used as a basis for general comparison and discussion of implications and future directions for modeling, and for theoretically understanding our engagement with visual art.

  13. An interacting systems model of infant habituation.

    Science.gov (United States)

    Sirois, Sylvain; Mareschal, Denis

    2004-10-01

    Habituation and related procedures are the primary behavioral tools used to assess perceptual and cognitive competence in early infancy. This article introduces a neurally constrained computational model of infant habituation. The model combines the two leading process theories of infant habituation into a single functional system that is grounded in functional brain circuitry. The HAB model (for Habituation, Autoassociation, and Brain) proposes that habituation behaviors emerge from the opponent, complementary processes of hippocampal selective inhibition and cortical long-term potentiation. Simulations of a seminal experiment by Fantz [Visual experience in infants: Decreased attention familiar patterns relative to novel ones. Science, 146, 668-670, 1964] are reported. The ability of the model to capture the fine detail of infant data (especially age-related changes in performance) underlines the useful contribution of neurocomputational models to our understanding of behavior in general, and of early cognition in particular.

  14. Comparison of Different Mathematical Models of Cavitation

    Directory of Open Access Journals (Sweden)

    Dorota HOMA

    2014-12-01

    Full Text Available Cavitation occurs during the flow when local pressure drops to the saturation pressure according to the temperature of the flow. It includes both evaporation and condensation of the vapor bubbles, which occur alternately with high frequency. Cavitation can be very dangerous, especially for pumps, because it leads to break of flow continuity, noise, vibration, erosion of blades and change in pump’s characteristics. Therefore it is very important for pump designers and users to avoid working in cavitation conditions. Simulation of flow can be very useful in that and can indicate if there is risk of cavitating flow occurrence. As this is a multiphase flow and quite complicated phenomena, there are a few mathematical models describing it. The aim of this paper is to make a short review of them and describe their approach to model cavitation. It is desirable to know differences between them to model this phenomenon properly.

  15. Comparison of Prediction-Error-Modelling Criteria

    DEFF Research Database (Denmark)

    Jørgensen, John Bagterp; Jørgensen, Sten Bay

    2007-01-01

    is a realization of a continuous-discrete multivariate stochastic transfer function model. The proposed prediction error-methods are demonstrated for a SISO system parameterized by the transfer functions with time delays of a continuous-discrete-time linear stochastic system. The simulations for this case suggest......Single and multi-step prediction-error-methods based on the maximum likelihood and least squares criteria are compared. The prediction-error methods studied are based on predictions using the Kalman filter and Kalman predictors for a linear discrete-time stochastic state space model, which...... computational resources. The identification method is suitable for predictive control....

  16. Comparison of Different Fuel Temperature Models

    Energy Technology Data Exchange (ETDEWEB)

    Weddig, Beatrice

    2003-02-01

    The purpose of this work is to improve the performance of the core calculation system used in Ringhals for in-core fuel management. It has been observed that, whereas the codes yield results that are in good agreement with measurements when the core operates at full nominal power, this agreement deteriorates noticeably when the reactor is running at reduced power. This deficiency of the code system was observed by comparing the calculated and measured boron concentrations in the moderator of the PWR. From the neutronic point of view, the difference between full power and reduced power in the same core is the different temperature of the fuel and the moderator. Whereas the coolant temperature can be measured and is thus relatively well known, the fuel temperature is only inferred from the moderator temperature as well as neutron physics and heat transfer calculations. The most likely reason for the above mentioned discrepancy is therefore the uncertainty of the fuel temperature at low power, and hence the incorrect calculation of the fuel temperature reactivity feedback through the so called Doppler effect. To obtain the fuel temperature at low power, usually some semi-empirical relations, sometimes called correlations, are used. The above-mentioned inaccuracy of the core calculation procedures can thus be tracked down to the insufficiency of these correlations. Therefore, the suggestion is that the above mentioned deficiency of the core calculation codes can be eliminated or reduced if the fuel temperature correlations are improved. An improved model, called the 30% model, is implemented in SIMULATE-3, the core calculation code used at Ringhals. The accuracy of the 30% model was compared to that of the present model by considering a number of cases, where measured values of the boron concentration at low power were available, and comparing them with calculated values using both the present and the new model. It was found that on the whole, the new fuel temperature

  17. Comparison of two different modelling tools

    DEFF Research Database (Denmark)

    Brix, Wiebke; Elmegaard, Brian

    2009-01-01

    In this paper a test case is solved using two different modelling tools, Engineering Equation Solver (EES) and WinDali, in order to compare the tools. The system of equations solved, is a static model of an evaporator used for refrigeration. The evaporator consists of two parallel channels......, and it is investigated how a non-uniform airflow influences the refrigerant mass flow rate distribution and the total cooling capacity of the heat exchanger. It is shown that the cooling capacity decreases significantly with increasing maldistribution of the airflow. Comparing the two simulation tools it is found...

  18. A Mechanistic Modeling Framework for Predicting Metabolic Interactions in Complex Mixtures

    Science.gov (United States)

    Cheng, Shu

    2011-01-01

    Background: Computational modeling of the absorption, distribution, metabolism, and excretion of chemicals is now theoretically able to describe metabolic interactions in realistic mixtures of tens to hundreds of substances. That framework awaits validation. Objectives: Our objectives were to a) evaluate the conditions of application of such a framework, b) confront the predictions of a physiologically integrated model of benzene, toluene, ethylbenzene, and m-xylene (BTEX) interactions with observed kinetics data on these substances in mixtures and, c) assess whether improving the mechanistic description has the potential to lead to better predictions of interactions. Methods: We developed three joint models of BTEX toxicokinetics and metabolism and calibrated them using Markov chain Monte Carlo simulations and single-substance exposure data. We then checked their predictive capabilities for metabolic interactions by comparison with mixture kinetic data. Results: The simplest joint model (BTEX interacting competitively for cytochrome P450 2E1 access) gives qualitatively correct and quantitatively acceptable predictions (with at most 50% deviations from the data). More complex models with two pathways or back-competition with metabolites have the potential to further improve predictions for BTEX mixtures. Conclusions: A systems biology approach to large-scale prediction of metabolic interactions is advantageous on several counts and technically feasible. However, ways to obtain the required parameters need to be further explored. PMID:21835728

  19. Ternary interaction parameters in calphad solution models

    Energy Technology Data Exchange (ETDEWEB)

    Eleno, Luiz T.F., E-mail: luizeleno@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica; Schön, Claudio G., E-mail: schoen@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Computational Materials Science Laboratory. Department of Metallurgical and Materials Engineering

    2014-07-01

    For random, diluted, multicomponent solutions, the excess chemical potentials can be expanded in power series of the composition, with coefficients that are pressure- and temperature-dependent. For a binary system, this approach is equivalent to using polynomial truncated expansions, such as the Redlich-Kister series for describing integral thermodynamic quantities. For ternary systems, an equivalent expansion of the excess chemical potentials clearly justifies the inclusion of ternary interaction parameters, which arise naturally in the form of correction terms in higher-order power expansions. To demonstrate this, we carry out truncated polynomial expansions of the excess chemical potential up to the sixth power of the composition variables. (author)

  20. Simulation of platelet, thrombus and erythrocyte hydrodynamic interactions in a 3D arteriole with in vivo comparison.

    Directory of Open Access Journals (Sweden)

    Weiwei Wang

    Full Text Available Cylindrical blood vessels, ellipsoid platelets and biconcave-shaped deformable erythrocytes (RBCs are important participants in hemostasis and thrombosis. However, due to the challenge of combining these components in simulation tools, few simulation studies have included all of them in realistic three-dimensional models. In the present study, we apply a recently developed simulation model to incorporate these components and analyze the flow in a thrombotic tubular arteriole, particularly the detailed hydrodynamic interactions between the thrombus shape, RBCs and platelets. It was found that at certain azimuth positions, the velocity drops in the proximity of both the upstream and downstream edge of the thrombus, which is accompanied by a rapid velocity increase in the narrowed region. The RBCs alter the flow profiles significantly from the typical low Reynolds (Re number flow, and also enhance the deposition of free flowing platelets onto the thrombus. By evaluating the platelet-thrombus interaction and platelet-RBC interaction together, several mechanisms of platelet deposition augmentation are identified. With in vivo data comparison, our model illustrates the potential of future thrombosis studies that incorporate detailed receptor-ligand adhesion modules.

  1. Comparison of multi-ħω shell-model results with MCAS

    Directory of Open Access Journals (Sweden)

    Svenne J. P.

    2014-03-01

    Full Text Available A multi-channel algebraic scattering (MCAS method has been used to obtain spectra of a number of light-mass nuclei, which are treated as a two-cluster system, here specifically a nucleon plus nucleus. To date, collective models have been used to specify the interactions between the nucleon and low-lying states of the nucleus that form the compound. For the case of the carbon isotopes, these studies have been complemented by sufficiently complex and complete shell-model calculations. Comparisons with the multi-ħω shell-model results provide new insights into the validity of those from MCAS.

  2. Designing experiments and analyzing data a model comparison perspective

    CERN Document Server

    Maxwell, Scott E

    2013-01-01

    Through this book's unique model comparison approach, students and researchers are introduced to a set of fundamental principles for analyzing data. After seeing how these principles can be applied in simple designs, students are shown how these same principles also apply in more complicated designs. Drs. Maxwell and Delaney believe that the model comparison approach better prepares students to understand the logic behind a general strategy of data analysis appropriate for various designs; and builds a stronger foundation, which allows for the introduction of more complex topics omitt

  3. Global comparison of three greenhouse climate models

    NARCIS (Netherlands)

    Bavel, van C.H.M.; Takakura, T.; Bot, G.P.A.

    1985-01-01

    Three dynamic simulation models for calculating the greenhouse climate and its energy requirements for both heating and cooling were compared by making detailed computations for each of seven sets of data. The data sets ranged from a cold winter day, requiring heating, to a hot summer day, requiring

  4. Climate impact of transportation A model comparison

    NARCIS (Netherlands)

    Girod, B.; Vuuren, D.P. van; Grahn, M.; Kitous, A.; Kim, S.H.; Kyle, P.

    2013-01-01

    Transportation contributes to a significant and rising share of global energy use and GHG emissions. Therefore modeling future travel demand, its fuel use, and resulting CO2 emission is highly relevant for climate change mitigation. In this study we compare the baseline projections for global

  5. Climate impact of transportation A model comparison

    NARCIS (Netherlands)

    Girod, B.; Vuuren, D.P. van; Grahn, M.; Kitous, A.; Kim, S.H.; Kyle, P.

    2013-01-01

    Transportation contributes to a significant and rising share of global energy use and GHG emissions. Therefore modeling future travel demand, its fuel use, and resulting CO2 emission is highly relevant for climate change mitigation. In this study we compare the baseline projections for global servic

  6. INFUSION: Modeling Robot and Crew Interaction

    Science.gov (United States)

    Laufenberg, Lawrence

    2003-01-01

    Brahms is a multi-agent modeling and simulation language and distributed runtime system developed at NASA. It can be used to model and run a simualtion of the distributed work activities of multiple agents, such as humans,robots, and software agents, to coordinate a mission on one or more locations.Brahms is being used to model activities at the Flashline Man Arctic Research Station for possible use in planning Mars missions. The station is located at Haughton Crater, Devon Island, Nutiavut, Arctic Canada.

  7. Two-Matrix model with ABAB interaction

    CERN Document Server

    Kazakov, V A

    1999-01-01

    Using recently developed methods of character expansions we solve exactly in the large N limit a new two-matrix model of hermitean matrices A and B with the action S={1øver 2}(\\tr A^2+\\tr B^2)-{\\alphaøver 4}(\\tr A^4+\\tr B^4)-{\\betaøver 2} \\tr(AB)^2. This model can be mapped onto a special case of the 8-vertex model on dynamical planar graphs. The solution is parametrized in terms of elliptic functions. A phase transition is found: the critical point is a conformal field theory with central charge c=1 coupled to 2D quantum gravity.

  8. Modeling leukocyte-leukocyte non-contact interactions in a lymph node.

    Directory of Open Access Journals (Sweden)

    Nicola Gritti

    Full Text Available The interaction among leukocytes is at the basis of the innate and adaptive immune-response and it is largely ascribed to direct cell-cell contacts. However, the exchange of a number of chemical stimuli (chemokines allows also non-contact interaction during the immunological response. We want here to evaluate the extent of the effect of the non-contact interactions on the observed leukocyte-leukocyte kinematics and their interaction duration. To this aim we adopt a simplified mean field description inspired by the Keller-Segel chemotaxis model, of which we report an analytical solution suited for slowly varying sources of chemokines. Since our focus is on the non-contact interactions, leukocyte-leukocyte contact interactions are simulated only by means of a space dependent friction coefficient of the cells. The analytical solution of the Keller-Segel model is then taken as the basis of numerical simulations of interactions between leukocytes and their duration. The mean field interaction force that we derive has a time-space separable form and depends on the chemotaxis sensitivity parameter as well as on the chemokines diffusion coefficient and their degradation rate. All these parameters affect the distribution of the interaction durations. We draw a successful qualitative comparison between simulated data and sets of experimental data for DC-NK cells interaction duration and other kinematic parameters. Remarkably, the predicted percentage of the leukocyte-leukocyte interactions falls in the experimental range and depends (~25% increase upon the chemotactic parameter indicating a non-negligible direct effect of the non-contact interaction on the leukocyte interactions.

  9. Modeling Type-IIn Interacting Supernovae

    Science.gov (United States)

    McDowell, Austin; Duffell, Paul; Kasen, Daniel

    2017-01-01

    Spectra of Type-IIn Supernovae (SNe) have shown evidence of interaction between SN ejecta and a surrounding circumstellar medium (CSM). Namely, narrow Hydrogen lines indicate that the fast moving ejecta slows after it collides with the slow moving CSM. However, observations of eta-Carinae and spectropolarimetry of SN2009ip during its 2012 explosion have shown that the CSM may often be asymmetric. In this study, we investigate the ability of an asymmetric CSM to disguise the characteristic narrow H lines expected from Type-IIn SNe. We perform two-dimensional hydrodynamic simulations of the interaction between supernova ejecta and CSM. The simulations are run using the moving-mesh hydrodynamics code JET. Previous studies have ignored possible asymmetries by limiting their calculations to one-dimension or assuming a spherically symmetric CSM. We calculate shock propagation within the disk and CSM heating rate to produce mock-bolometric light curves. We also track unshocked CSM mass and speculate on its effects on the observation of H lines.

  10. Strongly interacting matter from holographic QCD model

    CERN Document Server

    Chen, Yidian; Huang, Mei

    2016-01-01

    We introduce the 5-dimension dynamical holographic QCD model, which is constructed in the graviton-dilaton-scalar framework with the dilaton background field $\\Phi$ and the scalar field $X$ responsible for the gluodynamics and chiral dynamics, respectively. We review our results on the hadron spectra including the glueball and light meson spectra, QCD phase transitions and transport properties in the framework of the dynamical holographic QCD model.

  11. Utilitarian Supersymmetric Gauge Model of Particle Interactions

    CERN Document Server

    Ma, Ernest

    2010-01-01

    A remarkable U(1) gauge extension of the supersymmetric standard model was proposed eight years ago. It is anomaly-free, has no mu term, and conserves baryon and lepton numbers automatically. The phenomenology of a specific version of this model is discussed. In particular, leptoquarks are predicted, with couplings to the heavy singlet neutrinos, the scalar partners of which may be components of dark matter. The Majorana neutrino mass matrix itself may have two zero subdeterminants.

  12. Ferromagnetic interaction model of activity level in workplace communication

    Science.gov (United States)

    Akitomi, Tomoaki; Ara, Koji; Watanabe, Jun-ichiro; Yano, Kazuo

    2013-03-01

    The nature of human-human interaction, specifically, how people synchronize with each other in multiple-participant conversations, is described by a ferromagnetic interaction model of people’s activity levels. We found two microscopic human interaction characteristics from a real-environment face-to-face conversation. The first characteristic is that people quite regularly synchronize their activity level with that of the other participants in a conversation. The second characteristic is that the degree of synchronization increases as the number of participants increases. Based on these microscopic ferromagnetic characteristics, a “conversation activity level” was modeled according to the Ising model. The results of a simulation of activity level based on this model well reproduce macroscopic experimental measurements of activity level. This model will give a new insight into how people interact with each other in a conversation.

  13. Agent based models for wealth distribution with preference in interaction

    CERN Document Server

    Goswami, Sanchari

    2014-01-01

    We propose a set of conservative models in which agents exchange wealth with a preference in the choice of interacting agents in different ways. The common feature in all the models is that the temporary values of financial status of agents is a deciding factor for interaction. Other factors which may play important role are past interactions and wealth possessed by individuals. Wealth distribution, network properties and activity are the main quantities which have been studied. Evidence of phase transitions and other interesting features are presented. The results show that certain observations of real economic system can be reproduced by the models.

  14. The Growth of Structure in Interacting Dark Energy Models

    CERN Document Server

    Caldera-Cabral, Gabriela; Schaefer, Bjoern Malte

    2009-01-01

    If dark energy interacts with dark matter, there is a change in the background evolution of the universe, since the dark matter density no longer evolves as a^{-3}. In addition, the non-gravitational interaction affects the growth of structure. In principle, these changes allow us to detect and constrain an interaction in the dark sector. Here we investigate the growth factor and the weak lensing signal for a class of interacting dark energy models. In these models, the interaction is determined by a linear combination of the dark sector densities, with constant energy transfer rates. Assuming a normalization to today's values of dark matter density and overdensity, the signal of the interaction is an enhancement (suppression) of both the growth factor and the lensing power, when the energy transfer in the background is from dark matter to dark energy (dark energy to dark matter).

  15. [Comparison of two spectral mixture analysis models].

    Science.gov (United States)

    Wang, Qin-Jun; Lin, Qi-Zhong; Li, Ming-Xiao; Wang, Li-Ming

    2009-10-01

    A spectral mixture analysis experiment was designed to compare the spectral unmixing effects of linear spectral mixture analysis (LSMA) and constraint linear spectral mixture analysis (CLSMA). In the experiment, red, green, blue and yellow colors were printed on a coarse album as four end members. Thirty nine mixed samples were made according to each end member's different percent in one pixel. Then, field spectrometer was located on the top of the mixed samples' center to measure spectrum one by one. Inversion percent of each end member in the pixel was extracted using LSMA and CLSMA models. Finally, normalized mean squared error was calculated between inversion and real percent to compare the two models' effects on spectral unmixing. Results from experiment showed that the total error of LSMA was 0.30087 and that of CLSMA was 0.37552 when using all bands in the spectrum. Therefore, LSMA was 0.075 less than that of CLSMA when the whole bands of four end members' spectra were used. On the other hand, the total error of LSMA was 0.28095 and that of CLSMA was 0.29805 after band selection. So, LSMA was 0.017 less than that of CLSMA when bands selection was performed. Therefore, whether all or selected bands were used, the accuracy of LSMA was better than that of CLSMA because during the process of spectrum measurement, errors caused by instrument or human were introduced into the model, leading to that the measured data could not mean the strict requirement of CLSMA and therefore reduced its accuracy: Furthermore, the total error of LSMA using selected bands was 0.02 less than that using the whole bands. The total error of CLSMA using selected bands was 0.077 less than that using the whole bands. So, in the same model, spectral unmixing using selected bands to reduce the correlation of end members' spectra was superior to that using the whole bands.

  16. Performance Comparison of Gender and Age Group Recognition for Human-Robot Interaction

    Directory of Open Access Journals (Sweden)

    Myung-Won Lee

    2013-01-01

    Full Text Available In this paper, we focus on performance comparison of gender and age group recognition to perform robot’s application services for Human-Robot Interaction (HRI. HRI is a core technology that can naturally interact between human and robot. Among various HRI components, we concentrate audio-based techniques such as gender and age group recognition from multichannel microphones and sound board equipped withrobots. For comparative purposes, we perform the performancecomparison of Mel-Frequency Cepstral Coefficients (MFCC andLinear Prediction Coding Coefficients (LPCC in the feature extraction step, Support Vector Machine (SVM and C4.5 Decision Tree (DT in the classification step. Finally, we deal with the usefulness of gender and age group recognition for humanrobot interaction in home service robot environments.

  17. MicroShield/ISOCS gamma modeling comparison.

    Energy Technology Data Exchange (ETDEWEB)

    Sansone, Kenneth R

    2013-08-01

    Quantitative radiological analysis attempts to determine the quantity of activity or concentration of specific radionuclide(s) in a sample. Based upon the certified standards that are used to calibrate gamma spectral detectors, geometric similarities between sample shape and the calibration standards determine if the analysis results developed are qualitative or quantitative. A sample analyzed that does not mimic a calibrated sample geometry must be reported as a non-standard geometry and thus the results are considered qualitative and not quantitative. MicroShieldR or ISOCSR calibration software can be used to model non-standard geometric sample shapes in an effort to obtain a quantitative analytical result. MicroShieldR and Canberras ISOCSR software contain several geometry templates that can provide accurate quantitative modeling for a variety of sample configurations. Included in the software are computational algorithms that are used to develop and calculate energy efficiency values for the modeled sample geometry which can then be used with conventional analysis methodology to calculate the result. The response of the analytical method and the sensitivity of the mechanical and electronic equipment to the radionuclide of interest must be calibrated, or standardized, using a calibrated radiological source that contains a known and certified amount of activity.

  18. Evolution of Interacting Viscous Dark Energy Model in Einstein Cosmology

    Institute of Scientific and Technical Information of China (English)

    CHEN Ju-Hua; ZHOU Sheng; WANG Yong-Jiu

    2011-01-01

    We investigate the evolution of the viscous dark energy (DE) interacting with the dark matter (DM) in the Einstein cosmology model. By using the linearizing theory of the dynamical system, we find that, in our model,there exists a stable late time scaling solution which corresponds to the accelerating universe. We also find the unstable solution under some appropriate parameters. In order to alleviate the coincidence problem, some authors considered the effect of quantum correction due to the conform anomaly and the interacting dark energy with the dark matter. However, if we take into account the bulk viscosity of the cosmic fluid, the coincidence problem will be softened just like the interacting dark energy cosmology model. That is to say, both the non-perfect fluid model and the interacting the dark energy cosmic model can alleviate or soften the singularity of the universe.%@@ We investigate the evolution of the viscous dark energy (DE) interacting with the dark matter (DM) in the Einstein cosmology model.By using the linearizing theory of the dynamical system, we find that, in our model, there exists a stable late time scaling solution which corresponds to the accelerating universe.We also find the unstable solution under some appropriate parameters.In order to alleviate the coincidence problem, some authors considered the effect of quantum correction due to the conform anomaly and the interacting dark energy with the dark matter.However, if we take into account the bulk viscosity of the cosmic fluid, the coincidence problem will be softened just like the interacting dark energy cosmology model.That is to say, both the non-perfect fluid model and the interacting the dark energy cosmic model can alleviate or soften the singularity of the universe.

  19. Comparison and Analysis of Geometric Correction Models of Spaceborne SAR.

    Science.gov (United States)

    Jiang, Weihao; Yu, Anxi; Dong, Zhen; Wang, Qingsong

    2016-06-25

    Following the development of synthetic aperture radar (SAR), SAR images have become increasingly common. Many researchers have conducted large studies on geolocation models, but little work has been conducted on the available models for the geometric correction of SAR images of different terrain. To address the terrain issue, four different models were compared and are described in this paper: a rigorous range-doppler (RD) model, a rational polynomial coefficients (RPC) model, a revised polynomial (PM) model and an elevation derivation (EDM) model. The results of comparisons of the geolocation capabilities of the models show that a proper model for a SAR image of a specific terrain can be determined. A solution table was obtained to recommend a suitable model for users. Three TerraSAR-X images, two ALOS-PALSAR images and one Envisat-ASAR image were used for the experiment, including flat terrain and mountain terrain SAR images as well as two large area images. Geolocation accuracies of the models for different terrain SAR images were computed and analyzed. The comparisons of the models show that the RD model was accurate but was the least efficient; therefore, it is not the ideal model for real-time implementations. The RPC model is sufficiently accurate and efficient for the geometric correction of SAR images of flat terrain, whose precision is below 0.001 pixels. The EDM model is suitable for the geolocation of SAR images of mountainous terrain, and its precision can reach 0.007 pixels. Although the PM model does not produce results as precise as the other models, its efficiency is excellent and its potential should not be underestimated. With respect to the geometric correction of SAR images over large areas, the EDM model has higher accuracy under one pixel, whereas the RPC model consumes one third of the time of the EDM model.

  20. Comparison and Analysis of Geometric Correction Models of Spaceborne SAR

    Directory of Open Access Journals (Sweden)

    Weihao Jiang

    2016-06-01

    Full Text Available Following the development of synthetic aperture radar (SAR, SAR images have become increasingly common. Many researchers have conducted large studies on geolocation models, but little work has been conducted on the available models for the geometric correction of SAR images of different terrain. To address the terrain issue, four different models were compared and are described in this paper: a rigorous range-doppler (RD model, a rational polynomial coefficients (RPC model, a revised polynomial (PM model and an elevation derivation (EDM model. The results of comparisons of the geolocation capabilities of the models show that a proper model for a SAR image of a specific terrain can be determined. A solution table was obtained to recommend a suitable model for users. Three TerraSAR-X images, two ALOS-PALSAR images and one Envisat-ASAR image were used for the experiment, including flat terrain and mountain terrain SAR images as well as two large area images. Geolocation accuracies of the models for different terrain SAR images were computed and analyzed. The comparisons of the models show that the RD model was accurate but was the least efficient; therefore, it is not the ideal model for real-time implementations. The RPC model is sufficiently accurate and efficient for the geometric correction of SAR images of flat terrain, whose precision is below 0.001 pixels. The EDM model is suitable for the geolocation of SAR images of mountainous terrain, and its precision can reach 0.007 pixels. Although the PM model does not produce results as precise as the other models, its efficiency is excellent and its potential should not be underestimated. With respect to the geometric correction of SAR images over large areas, the EDM model has higher accuracy under one pixel, whereas the RPC model consumes one third of the time of the EDM model.

  1. A COMPARISON OF SEMANTIC SIMILARITY MODELS IN EVALUATING CONCEPT SIMILARITY

    Directory of Open Access Journals (Sweden)

    Q. X. Xu

    2012-08-01

    Full Text Available The semantic similarities are important in concept definition, recognition, categorization, interpretation, and integration. Many semantic similarity models have been established to evaluate semantic similarities of objects or/and concepts. To find out the suitability and performance of different models in evaluating concept similarities, we make a comparison of four main types of models in this paper: the geometric model, the feature model, the network model, and the transformational model. Fundamental principles and main characteristics of these models are introduced and compared firstly. Land use and land cover concepts of NLCD92 are employed as examples in the case study. The results demonstrate that correlations between these models are very high for a possible reason that all these models are designed to simulate the similarity judgement of human mind.

  2. Comparison of aerodynamic models for Vertical Axis Wind Turbines

    DEFF Research Database (Denmark)

    Ferreira, C. Simão; Aagaard Madsen, Helge; Barone, M.

    2014-01-01

    Multi-megawatt Vertical Axis Wind Turbines (VAWTs) are experiencing an increased interest for floating offshore applications. However, VAWT development is hindered by the lack of fast, accurate and validated simulation models. This work compares six different numerical models for VAWTS: a multiple...... streamtube model, a double-multiple streamtube model, the actuator cylinder model, a 2D potential flow panel model, a 3D unsteady lifting line model, and a 2D conformal mapping unsteady vortex model. The comparison covers rotor configurations with two NACA0015 blades, for several tip speed ratios, rotor...... solidity and fixed pitch angle, included heavily loaded rotors, in inviscid flow. The results show that the streamtube models are inaccurate, and that correct predictions of rotor power and rotor thrust are an effect of error cancellation which only occurs at specific configurations. The other four models...

  3. a Comparison of Semantic Similarity Models in Evaluating Concept Similarity

    Science.gov (United States)

    Xu, Q. X.; Shi, W. Z.

    2012-08-01

    The semantic similarities are important in concept definition, recognition, categorization, interpretation, and integration. Many semantic similarity models have been established to evaluate semantic similarities of objects or/and concepts. To find out the suitability and performance of different models in evaluating concept similarities, we make a comparison of four main types of models in this paper: the geometric model, the feature model, the network model, and the transformational model. Fundamental principles and main characteristics of these models are introduced and compared firstly. Land use and land cover concepts of NLCD92 are employed as examples in the case study. The results demonstrate that correlations between these models are very high for a possible reason that all these models are designed to simulate the similarity judgement of human mind.

  4. Interactional models for adults of two populations with maturation delays

    Institute of Scientific and Technical Information of China (English)

    HE Ze-rong; LI Jian-quan

    2008-01-01

    This paper is concerned with interactional models for adults of two species delayed by their mature periods. The existence and local stability of equilibria are discussed thoroughly for competitive systems, cooperative systems and predator-prey systems, respectively. For systems with interaction of competition and cooperation, it is found that the two populations are uniformly persistent if the positive equilibrium is stable. For predator-prey interaction, however, some further conditions are needed to guarantee the persistence of the systems.

  5. The ‘hit’ phenomenon: a mathematical model of human dynamics interactions as a stochastic process

    Science.gov (United States)

    Ishii, Akira; Arakaki, Hisashi; Matsuda, Naoya; Umemura, Sanae; Urushidani, Tamiko; Yamagata, Naoya; Yoshida, Narihiko

    2012-06-01

    A mathematical model for the ‘hit’ phenomenon in entertainment within a society is presented as a stochastic process of human dynamics interactions. The model uses only the advertisement budget time distribution as an input, and word-of-mouth (WOM), represented by posts on social network systems, is used as data to make a comparison with the calculated results. The unit of time is days. The WOM distribution in time is found to be very close to the revenue distribution in time. Calculations for the Japanese motion picture market based on the mathematical model agree well with the actual revenue distribution in time.

  6. Modeling Interacting Galaxies: NGC 4449 revisited

    Science.gov (United States)

    Theis, C.; Jungwirth, G.; Petsch, H.; Walter, F.

    2011-01-01

    Observing nearby interacting galaxies is a key to understanding galactic physics provided that we know the spatial and temporal perturbations acting on these galaxies. Thus, we have to know the orbits and the gross internal properties of the galaxies. In order to cope with the related extended parameter space, we developed the code MINGA which combines a genetic algorithm with a fast N-body method. As an example for this method, we present a re-analysis of the prototypical system NGC 4449 which is now based on both, the full HI data cube of the NGC 4449 system and on improved determinations of the galactic orbits within a restricted N-body calculation.

  7. A Comparison Between Five Models Of Software Engineering

    Directory of Open Access Journals (Sweden)

    Nabil Mohammed Ali Munassar

    2010-09-01

    Full Text Available This research deals with a vital and important issue in computer world. It is concerned with the software management processes that examine the area of software development through the development models, which are known as software development life cycle. It represents five of the development models namely, waterfall, Iteration, V-shaped, spiral and Extreme programming. These models have advantages and disadvantages as well. Therefore, the main objective of this research is to represent different models of software development and make a comparison between them to show the features and defects of each model.

  8. Vector condensate model of electroweak interactions

    CERN Document Server

    Cynolter, G

    1996-01-01

    Motivated by the fact that the Higgs is not seen we proposed a version of the standard model where the scalar doublet is replaced by a doublet of vector fields. The neutral member of the doublet forms a nonvanishing condensate generating masses for the weak gauge bosons. The phenomenology of the model is studied in high energy e+e- colliders and in the formalism of the parameters S,T,U. The experiments recquire heavy new particles at least 200 GeV which can be produced at the next generation of colliders.

  9. Delay analysis of interacting queues with an approximate model

    Science.gov (United States)

    Ephremides, Anthony; Zhu, Rong-Zhu

    1987-02-01

    An approximate model of coupled Markov chains is proposed and analyzed for a slotted ALOHA system with a finite number of buffered nodes. This model differs from earlier ones in that it attempts to capture the interdependence between the nodes. The analytical results lead to a set of equations that, when solved numerically, yield the average packet delay. Comparison between computational and simulation results for a small number of nodes show excellent agreement for most throughput values, except for values near saturation. Numerical comparisons for a two-node system show that a nonsymmetric loading of the system provides better delay-throughput performance than a symmetric one.

  10. Becker and Lomnitz rheological models: A comparison

    Science.gov (United States)

    Mainardi, Francesco; Spada, Giorgio

    2012-07-01

    The viscoelastic material functions for the Becker and the Lomnitz rheological models, sometimes employed to describe the transient flow of rocks, are studied and compared. Their creep functions, which are known in a closed form, share a similar time dependence and asymptotic behavior. This is also found for the relaxation functions, obtained by solving numerically a Volterra equation of the second kind. We show that the two rheologies constitute a clear example of broadly similar creep and relaxation patterns associated with neatly distinct retardation spectra, for which analytical expressions are available.

  11. A comparison between algebraic models of molecular spectroscopy

    CERN Document Server

    Bijker, R; Lemus, R; Arias, J M; Pérez-Bernal, F

    1998-01-01

    We discuss a symmetry-adapted algebraic (or vibron) model for molecular spectroscopy. The model is formulated in terms of tensor operators under the molecular point group. In this way, we have identified interactions that are absent in previous versions of the vibron model, in which the Hamiltonian is expressed in terms of Casimir operators and their products. The inclusion of these new interactions leads to reliable spectroscopic predictions. As an example we study the vibrational excitations of the methane molecule, and compare our results with those obtained in other algebraic models.

  12. Matrix models of RNA folding with external interactions: A review

    Indian Academy of Sciences (India)

    I Garg; N Deo

    2011-11-01

    The matrix model of (simplified) RNA folding with an external linear interaction in the action of the partition function is reviewed. The important results for structure combinatorics of the model are discussed and analysed in terms of the already existing models.

  13. Formal modelling techniques in human-computer interaction

    NARCIS (Netherlands)

    Haan, de G.; Veer, van der G.C.; Vliet, van J.C.

    1991-01-01

    This paper is a theoretical contribution, elaborating the concept of models as used in Cognitive Ergonomics. A number of formal modelling techniques in human-computer interaction will be reviewed and discussed. The analysis focusses on different related concepts of formal modelling techniques in hum

  14. Self-interaction mechanism in Hagen's massive vector model

    CERN Document Server

    Arias, P J

    2004-01-01

    It is shown that the non-abelian vectorial model, proposed by C.R.Hagen is obtained using the self-interaction mechanism. The equivalence between this model and the non-abelian topologically massive one is studied showing that the existing equivalence between the abelian models is not sustained.

  15. Approximate Solutions of Interactive Dynamic Influence Diagrams Using Model Clustering

    DEFF Research Database (Denmark)

    Zeng, Yifeng; Doshi, Prashant; Qiongyu, Cheng

    2007-01-01

    Interactive dynamic influence diagrams (I-DIDs) offer a transparent and semantically clear representation for the sequential decision-making problem over multiple time steps in the presence of other interacting agents. Solving I-DIDs exactly involves knowing the solutions of possible models...

  16. Volume Sculpting: Intuitive, Interactive 3D Shape Modelling

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas

    A system for interactive modelling of 3D shapes on a computer is presented. The system is intuitive and has a flat learning curve. It is especially well suited to the creation of organic shapes and shapes of complex topology. The interaction is simple; the user can either add new shape features...

  17. Object interaction competence model v. 2.0

    DEFF Research Database (Denmark)

    Bennedsen, Jens; Schulte, C.

    2013-01-01

    Teaching and learning object oriented programming has to take into account the specific object oriented characteristics of program execution, namely the interaction of objects during runtime. Prior to the research reported in this article, we have developed a competence model for object interaction...

  18. Self-consistent Models of Strong Interaction with Chiral Symmetry

    Science.gov (United States)

    Nambu, Y.; Pascual, P.

    1963-04-01

    Some simple models of (renormalizable) meson-nucleon interaction are examined in which the nucleon mass is entirely due to interaction and the chiral ( gamma {sub 5}) symmetry is "broken'' to become a hidden symmetry. It is found that such a scheme is possible provided that a vector meson is introduced as an elementary field. (auth)

  19. Bilingual Lexical Interactions in an Unsupervised Neural Network Model

    Science.gov (United States)

    Zhao, Xiaowei; Li, Ping

    2010-01-01

    In this paper we present an unsupervised neural network model of bilingual lexical development and interaction. We focus on how the representational structures of the bilingual lexicons can emerge, develop, and interact with each other as a function of the learning history. The results show that: (1) distinct representations for the two lexicons…

  20. Approximate Solutions of Interactive Dynamic Influence Diagrams Using Model Clustering

    DEFF Research Database (Denmark)

    Zeng, Yifeng; Doshi, Prashant; Qiongyu, Cheng

    2007-01-01

    Interactive dynamic influence diagrams (I-DIDs) offer a transparent and semantically clear representation for the sequential decision-making problem over multiple time steps in the presence of other interacting agents. Solving I-DIDs exactly involves knowing the solutions of possible models of th....... We discuss the error bound of the approximation technique and demonstrate its empirical performance....

  1. Bilingual Lexical Interactions in an Unsupervised Neural Network Model

    Science.gov (United States)

    Zhao, Xiaowei; Li, Ping

    2010-01-01

    In this paper we present an unsupervised neural network model of bilingual lexical development and interaction. We focus on how the representational structures of the bilingual lexicons can emerge, develop, and interact with each other as a function of the learning history. The results show that: (1) distinct representations for the two lexicons…

  2. Interactive Communication Systems Simulation Model (ICSSM) Extension.

    Science.gov (United States)

    1983-07-01

    IERC, SEPOCH, CARRI, CARRO ) CHIP (DELTC, Generates samples SFSK chip- KDWVFM, NSAMP, modulation waveform. IERC, SMPCI, SMPCQ, SEPOCH) MDULAT (IT, TQ...IERC, SOTS, tion reference. CARRI, CARRO , SMPCI, SMPCQ) RESTOR (IDXP, RP, Modeling utility for storing work- SO, THQ, PHI, ing parameter values in

  3. Interactions In Space For Archaeological Models

    CERN Document Server

    Evans, T S; Knappett, C

    2011-01-01

    In this article we examine a variety of quantitative models for describing archaeological networks, with particular emphasis on the maritime networks of the Aegean Middle Bronze Age. In particular, we discriminate between those gravitational networks that are most likely (maximum entropy) and most efficient (best cost/benefit outcomes).

  4. A single product perishing inventory model with demand interaction ...

    African Journals Online (AJOL)

    A single product perishing inventory model with demand interaction. ... satisfied may be satisfied by an item in Phase II, based on a probability measure. ... the probability distribution of the inventory level at any arbitrary point in time is obtained.

  5. Integrability and Quantum Phase Transitions in Interacting Boson Models

    CERN Document Server

    Dukelsky, J; García-Ramos, J E; Pittel, S

    2003-01-01

    The exact solution of the boson pairing hamiltonian given by Richardson in the sixties is used to study the phenomena of level crossings and quantum phase transitions in the integrable regions of the sd and sdg interacting boson models.

  6. Effective Q-Q Interactions in Constituent Quark Models

    CERN Document Server

    Glozman, L Ya; Plessas, W; Varga, K; Wagenbrun, R F

    1998-01-01

    We study the performance of some recent potential models suggested as effective interactions between constituent quarks. In particular, we address constituent quark models for baryons with hybrid Q-Q interactions stemming from one-gluon plus meson exchanges. Upon recalculating two of such models we find them to fail in describing the N and \\Delta spectra. Our calculations are based on accurate solutions of the three-quark systems in both a variational Schrödinger and a rigorous Faddeev approach. It is argued that hybrid {Q-Q} interactions encounter difficulties in describing baryon spectra due to the specific contributions from one-gluon and pion exchanges together. In contrast, a chiral constituent quark model with a Q-Q interaction solely derived from Goldstone-boson exchange is capable of providing a unified description of both the N and \\Delta spectra in good agreement with phenomenology.

  7. Multiple comparisons in genetic association studies: a hierarchical modeling approach.

    Science.gov (United States)

    Yi, Nengjun; Xu, Shizhong; Lou, Xiang-Yang; Mallick, Himel

    2014-02-01

    Multiple comparisons or multiple testing has been viewed as a thorny issue in genetic association studies aiming to detect disease-associated genetic variants from a large number of genotyped variants. We alleviate the problem of multiple comparisons by proposing a hierarchical modeling approach that is fundamentally different from the existing methods. The proposed hierarchical models simultaneously fit as many variables as possible and shrink unimportant effects towards zero. Thus, the hierarchical models yield more efficient estimates of parameters than the traditional methods that analyze genetic variants separately, and also coherently address the multiple comparisons problem due to largely reducing the effective number of genetic effects and the number of statistically "significant" effects. We develop a method for computing the effective number of genetic effects in hierarchical generalized linear models, and propose a new adjustment for multiple comparisons, the hierarchical Bonferroni correction, based on the effective number of genetic effects. Our approach not only increases the power to detect disease-associated variants but also controls the Type I error. We illustrate and evaluate our method with real and simulated data sets from genetic association studies. The method has been implemented in our freely available R package BhGLM (http://www.ssg.uab.edu/bhglm/).

  8. Tip Studies using CFD and Comparison with Tip Loss Models

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    2004-01-01

    of the averaged axial induction factor and the normal and tangential loads are compared with those of a standard blade element momentum code using 2D calibrated airfoil data for a wind speed of 9 m s(-1), where the agreement in computed power is good. Further, a comparison with a new tip loss model proposed...

  9. Interactive Modelling and Simulation of Human Motion

    DEFF Research Database (Denmark)

    Engell-Nørregård, Morten Pol

    Dansk resumé Denne ph.d.-afhandling beskæftiger sig med modellering og simulation af menneskelig bevægelse. Emnerne i denne afhandling har mindst to ting til fælles. For det første beskæftiger de sig med menneskelig bevægelse. Selv om de udviklede modeller også kan benyttes til andre ting,er det ....... Endvidere kan den anvendes med enhver softbody simuleringsmodel som finite elements eller mass spring systemer. • En kontrol metode til deformerbare legemer baseret på rum tids opti- mering. fremgangsmåden kan anvendes til at styre sammentrækning af muskler i en muskel simulering....

  10. Advanced interaction techniques for medical models

    OpenAIRE

    Monclús, Eva

    2014-01-01

    Advances in Medical Visualization allows the analysis of anatomical structures with the use of 3D models reconstructed from a stack of intensity-based images acquired through different techniques, being Computerized Tomographic (CT) modality one of the most common. A general medical volume graphics application usually includes an exploration task which is sometimes preceded by an analysis process where the anatomical structures of interest are first identified. ...

  11. Interactive Modelling and Simulation of Human Motion

    DEFF Research Database (Denmark)

    Engell-Nørregård, Morten Pol

    Dansk resumé Denne ph.d.-afhandling beskæftiger sig med modellering og simulation af menneskelig bevægelse. Emnerne i denne afhandling har mindst to ting til fælles. For det første beskæftiger de sig med menneskelig bevægelse. Selv om de udviklede modeller også kan benyttes til andre ting,er det...... menneskers led, der udviser både ikke-konveksitet og flere frihedsgrader • En generel og alsidig model for aktivering af bløde legemer. Modellen kan anvendes som et animations værktøj, men er lige så velegnet til simulering af menneskelige muskler, da den opfylder de grundlæggende fysiske principper...... primære fokus på at modellere den menneskelige krop. For det andet, beskæftiger de sig alle med simulering som et redskab til at syntetisere bevægelse og dermed skabe animationer. Dette er en vigtigt pointe, da det betyder, at vi ikke kun skaber værktøjer til animatorer, som de kan bruge til at lave sjove...

  12. Phase space analysis of some interacting Chaplygin gas models

    Energy Technology Data Exchange (ETDEWEB)

    Khurshudyan, M. [Academy of Sciences of Armenia, Institute for Physical Research, Ashtarak (Armenia); Tomsk State University of Control Systems and Radioelectronics, Laboratory for Theoretical Cosmology, Tomsk (Russian Federation); Tomsk State Pedagogical University, Department of Theoretical Physics, Tomsk (Russian Federation); Myrzakulov, R. [Eurasian National University, Eurasian International Center for Theoretical Physics, Astana (Kazakhstan)

    2017-02-15

    In this paper we discuss a phase space analysis of various interacting Chaplygin gas models in general relativity. Linear and nonlinear sign changeable interactions are considered. For each case appropriate late time attractors of field equations are found. The Chaplygin gas is one of the dark fluids actively considered in modern cosmology due to the fact that it is a joint model of dark energy and dark matter. (orig.)

  13. The MICOR hadronization model with final state interactions

    CERN Document Server

    Csizmadia, P

    2002-01-01

    Final state interactions on the hadron spectra obtained from the MIcroscopic COalescence Rehadronization (MICOR) model are investigated. MICOR generates baryon and meson resonances in an out- of-equilibrium distribution, directly from quark matter. At the next step, resonances decay into stable hadrons by the JETSET event generator. The final state interactions are simulated using a hadronic cascade, with initial momentum distributions given by MICOR. For the initial space distributions, two simple models are applied and compared. (12 refs).

  14. IBAR: Interacting boson model calculations for large system sizes

    Science.gov (United States)

    Casperson, R. J.

    2012-04-01

    Scaling the system size of the interacting boson model-1 (IBM-1) into the realm of hundreds of bosons has many interesting applications in the field of nuclear structure, most notably quantum phase transitions in nuclei. We introduce IBAR, a new software package for calculating the eigenvalues and eigenvectors of the IBM-1 Hamiltonian, for large numbers of bosons. Energies and wavefunctions of the nuclear states, as well as transition strengths between them, are calculated using these values. Numerical errors in the recursive calculation of reduced matrix elements of the d-boson creation operator are reduced by using an arbitrary precision mathematical library. This software has been tested for up to 1000 bosons using comparisons to analytic expressions. Comparisons have also been made to the code PHINT for smaller system sizes. Catalogue identifier: AELI_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AELI_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 3 No. of lines in distributed program, including test data, etc.: 28 734 No. of bytes in distributed program, including test data, etc.: 4 104 467 Distribution format: tar.gz Programming language: C++ Computer: Any computer system with a C++ compiler Operating system: Tested under Linux RAM: 150 MB for 1000 boson calculations with angular momenta of up to L=4 Classification: 17.18, 17.20 External routines: ARPACK (http://www.caam.rice.edu/software/ARPACK/) Nature of problem: Construction and diagonalization of large Hamiltonian matrices, using reduced matrix elements of the d-boson creation operator. Solution method: Reduced matrix elements of the d-boson creation operator have been stored in data files at machine precision, after being recursively calculated with higher than machine precision. The Hamiltonian matrix is calculated and diagonalized, and the requested transition strengths are calculated

  15. COMPARISON BETWEEN MODELS FOR CALCULATION OF INDUSTRIAL HOT ROLLING LOADS

    OpenAIRE

    Antonio Augusto Gorni; Marcos Roberto Soares da Silva

    2012-01-01

    An evaluation is made about the precision of hot strip rolling mill loads at the F1 stand calculated according to the theoretical models of Orowan, Sims, Alexander-Ford, Orowan-Pascoe, Ekelund and Tselikov in comparison to real values got for carbon-manganese steels. In the deterministic approach, without any fit of the calculated values to real data, Orowan, Sims and Alexander-Models show best levels of precision, as expected from the information got in the literature. However, i...

  16. Artificial neural networks modeling gene-environment interaction

    Directory of Open Access Journals (Sweden)

    Günther Frauke

    2012-05-01

    Full Text Available Abstract Background Gene-environment interactions play an important role in the etiological pathway of complex diseases. An appropriate statistical method for handling a wide variety of complex situations involving interactions between variables is still lacking, especially when continuous variables are involved. The aim of this paper is to explore the ability of neural networks to model different structures of gene-environment interactions. A simulation study is set up to compare neural networks with standard logistic regression models. Eight different structures of gene-environment interactions are investigated. These structures are characterized by penetrance functions that are based on sigmoid functions or on combinations of linear and non-linear effects of a continuous environmental factor and a genetic factor with main effect or with a masking effect only. Results In our simulation study, neural networks are more successful in modeling gene-environment interactions than logistic regression models. This outperfomance is especially pronounced when modeling sigmoid penetrance functions, when distinguishing between linear and nonlinear components, and when modeling masking effects of the genetic factor. Conclusion Our study shows that neural networks are a promising approach for analyzing gene-environment interactions. Especially, if no prior knowledge of the correct nature of the relationship between co-variables and response variable is present, neural networks provide a valuable alternative to regression methods that are limited to the analysis of linearly separable data.

  17. Modeling microwave/electron-cloud interaction

    CERN Document Server

    Mattes, M; Zimmermann, F

    2013-01-01

    Starting from the separate codes BI-RME and ECLOUD or PyECLOUD, we are developing a novel joint simulation tool, which models the combined effect of a charged particle beam and of microwaves on an electron cloud. Possible applications include the degradation of microwave transmission in tele-communication satellites by electron clouds; the microwave-transmission tecchniques being used in particle accelerators for the purpose of electroncloud diagnostics; the microwave emission by the electron cloud itself in the presence of a magnetic field; and the possible suppression of electron-cloud formation in an accelerator by injecting microwaves of suitable amplitude and frequency. A few early simulation results are presented.

  18. Comparison of the Beckmann model with bidirectional reflectance measurements.

    Science.gov (United States)

    Smith, T. F.; Hering, R. G.

    1973-01-01

    The Beckmann model is compared with recently reported bidirectional reflectance measurements. Comparisons revealed that monochromatic specular and bidirectional reflectance measurements are not adequately described by corresponding results evaluated from the model using mechanically acquired surface roughness parameters (rms height and rms slope). Significant improvement between measurements and predictions of the model is observed when optically acquired surface roughness parameters are used. Specular reflectance measurements for normal to intermediate polar angles of incidence are adequately represented by the model provided values of optical roughness multiplied by cosine of polar angle of incidence are less than 27 times average optical rms slope.

  19. nIFTy Cosmology: Comparison of Galaxy Formation Models

    CERN Document Server

    Knebe, Alexander; Thomas, Peter A; Benson, Andrew; Blaizot, Jeremy; Bower, Richard; Carretero, Jorge; Castander, Francisco J; Cattaneo, Andrea; Cora, Sofia A; Croton, Darren J; Cui, Weiguang; Cunnama, Daniel; De Lucia, Gabriella; Devriendt, Julien E; Elahi, Pascal J; Font, Andreea; Fontanot, Fabio; Garcia-Bellido, Juan; Gargiulo, Ignacio D; Gonzalez-Perez, Violeta; Helly, John; Henriques, Bruno; Hirschmann, Michaela; Lee, Jaehyun; Mamon, Gary A; Monaco, Pierluigi; Onions, Julian; Padilla, Nelson D; Power, Chris; Pujol, Arnau; Skibba, Ramin A; Somerville, Rachel S; Srisawat, Chaichalit; Vega-Martinez, Cristian A; Yi, Sukyoung K

    2015-01-01

    We present a comparison of 14 galaxy formation models: 12 different semi-analytical models and 2 halo-occupation distribution models for galaxy formation based upon the same cosmological simulation and merger tree information derived from it. The participating codes have proven to be very successful in their own right but they have all been calibrated independently using various observational data sets, stellar models, and merger trees. In this paper we apply them without recalibration and this leads to a wide variety of predictions for the stellar mass function, specific star formation rates, stellar-to- halo mass ratios, and the abundance of orphan galaxies. The scatter is much larger than seen in previous comparison studies primarily because the codes have been used outside of their native environment within which they are well tested and calibrated. The purpose of the `nIFTy comparison of galaxy formation models' is to bring together as many different galaxy formation modellers as possible and to investig...

  20. Modeling of high power laser interaction with metals

    Science.gov (United States)

    Mustafa, Kurt; Zahide, Demircioǧlu

    2017-02-01

    Laser matter interaction has been very popular subject from the first recognition of lasers. Laser application in industry or laboratory applications are based on definite interactions of the laser beam with the workpiece. In this paper, an effective model related with high power radiation interaction with metals is presented. In metals, Lorentz-Drude model is used calculate permeability theoretically. The plasma frequency was calculated at various temperatures and using the obtained results the refractive index of the metal (Ag) was investigated. The calculation result revealed that the effect of the temperature need to be considered at reflection and transmission of the laser beam.

  1. Exactly solved models of interacting dark matter and dark energy

    CERN Document Server

    Chimento, Luis P

    2012-01-01

    We introduce an effective one-fluid description of the interacting dark sector in a spatially flat Friedmann-Robertson-Walker space-time and investigate the stability of the power-law solutions. We find the "source equation" for the total energy density and determine the energy density of each dark component. We study linear and nonlinear interactions which depend on the dark matter and dark energy densities, their first derivatives, the total energy density with its derivatives up to second order and the scale factor. We solve the evolution equations of the dark components for both interactions, examine exhaustively several examples and show cases where the problem of the coincidence is alleviated. We show that a generic nonlinear interaction gives rise to the "relaxed Chaplygin gas model" whose effective equation of state includes the variable modified Chaplygin gas model while some others nonlinear interactions yield de Sitter and power-law scenarios.

  2. Detecting feature interactions in Web services with model checking techniques

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    As a platform-independent software system, a Web service is designed to offer interoperability among diverse and heterogeneous applications.With the introduction of service composition in the Web service creation, various message interactions among the atomic services result in a problem resembling the feature interaction problem in the telecommunication area.This article defines the problem as feature interaction in Web services and proposes a model checking-based detection method.In the method, the Web service description is translated to the Promela language - the input language of the model checker simple promela interpreter (SPIN), and the specific properties, expressed as linear temporal logic (LTL) formulas, are formulated according to our classification of feature interaction.Then, SPIN is used to check these specific properties to detect the feature interaction in Web services.

  3. MODEL OF LASER INTERACTION WITH LIQUID DROPLET

    Directory of Open Access Journals (Sweden)

    K. N. Volkov,

    2016-09-01

    Full Text Available Subject of Research. A mathematical model of optical breakdown in the dielectric liquid droplets when exposed to pulsed laser radiation was developed. The process is considered in several stages: heating, evaporation of the particle, forming a steam halo, ionization of the steam halo. Numerical study was carried out on the basis of the mathematical model to determine the threshold characteristics of the laser pulse. Main Results.Distributions of pressure, density and temperature of the particle steam halo were obtained by means of a calculation. The temperature field around the liquid droplet was determined. It has been found that at high energies in the gas bubble, the conditions are provided for thermal gas ionization and start of the electron avalanche, leading to plasma formation. Due to the volumetric heat generation, the droplet is overheated and is in a metastable state. The plasma cloud is almost opaque to radiation that causes an abrupt increase of temperature. As a result, an explosion occurs inside the droplet with the formation of a shock wave that is propagating outward. Practical Relevance.The results can be used to assess the performance of high-power laser scanning (LIDAR under the presence of liquid droplets in the atmosphere and other suspensions. Lasers can be used in fire and explosion aerospace systems. Obtained findings can be applied also in the systems of laser ignition and detonation initiation.

  4. Coexistence of Interacting Opinions in a Generalized Sznajd Model

    CERN Document Server

    Timpanaro, André M

    2011-01-01

    The Sznajd model is a sociophysics model that mimics the propagation of opinions in a closed society, where the interactions favour groups of agreeing people. It is based in the Ising and Potts ferromagnetic models and although the original model used only linear chains, it has since been adapted to general networks. This model has a very rich transient, that has been used to model several aspects of elections, but its stationary states are always consensus states. In order to model more complex behaviours we have, in a recent work, introduced the idea of biases and prejudices to the Sznajd model, by generalizing the bounded confidence rule that is common to many continuous opinion models. In that work we have found that the mean-field version of this model (corresponding to a complete network) allows for stationary states where non-interacting opinions survive, but never for the coexistence of interacting opinions. In the present work, we provide networks that allow for the coexistence of interacting opinion...

  5. Element-specific density profiles in interacting biomembrane models

    Science.gov (United States)

    Schneck, Emanuel; Rodriguez-Loureiro, Ignacio; Bertinetti, Luca; Marin, Egor; Novikov, Dmitri; Konovalov, Oleg; Gochev, Georgi

    2017-03-01

    Surface interactions involving biomembranes, such as cell–cell interactions or membrane contacts inside cells play important roles in numerous biological processes. Structural insight into the interacting surfaces is a prerequisite to understand the interaction characteristics as well as the underlying physical mechanisms. Here, we work with simplified planar experimental models of membrane surfaces, composed of lipids and lipopolymers. Their interaction is quantified in terms of pressure–distance curves using ellipsometry at controlled dehydrating (interaction) pressures. For selected pressures, their internal structure is investigated by standing-wave x-ray fluorescence (SWXF). This technique yields specific density profiles of the chemical elements P and S belonging to lipid headgroups and polymer chains, as well as counter-ion profiles for charged surfaces.

  6. Geant4 models for simulation of hadron/ion nuclear interactions at moderate and low energies.

    Science.gov (United States)

    Ivantchenko, Anton; Ivanchenko, Vladimir; Quesada, Jose-Manuel; Wright, Dennis

    The Geant4 toolkit is intended for Monte Carlo simulation of particle transport in media. It was initially designed for High Energy Physics purposes such as experiments at the Large Hadron Collider (LHC) at CERN. The toolkit offers a set of models allowing effective simulation of cosmic ray interactions with different materials. For moderate and low energy hadron/ion interactions with nuclei there are a number of competitive models: Binary and Bertini intra-nuclear cascade models, quantum molecular dynamic model (QMD), INCL/ABLA cascade model, and Chiral Invariant Phase Space Decay model (CHIPS). We report the status of these models for the recent version of Geant4 (release 9.3, December 2009). The Bertini cascade in-ternal cross sections were upgraded. The native Geant4 precompound and deexcitation models were used in the Binary cascade and QMD. They were significantly improved including emis-sion of light fragments, the Fermi break-up model, the General Evaporation Model (GEM), the multi-fragmentation model, and the fission model. Comparisons between model predictions and data for thin target experiments for neutron, proton, light ions, and isotope production are presented and discussed. The focus of these validations is concentrated on target materials important for space missions.

  7. Arima model and exponential smoothing method: A comparison

    Science.gov (United States)

    Wan Ahmad, Wan Kamarul Ariffin; Ahmad, Sabri

    2013-04-01

    This study shows the comparison between Autoregressive Moving Average (ARIMA) model and Exponential Smoothing Method in making a prediction. The comparison is focused on the ability of both methods in making the forecasts with the different number of data sources and the different length of forecasting period. For this purpose, the data from The Price of Crude Palm Oil (RM/tonne), Exchange Rates of Ringgit Malaysia (RM) in comparison to Great Britain Pound (GBP) and also The Price of SMR 20 Rubber Type (cents/kg) with three different time series are used in the comparison process. Then, forecasting accuracy of each model is measured by examinethe prediction error that producedby using Mean Squared Error (MSE), Mean Absolute Percentage Error (MAPE), and Mean Absolute deviation (MAD). The study shows that the ARIMA model can produce a better prediction for the long-term forecasting with limited data sources, butcannot produce a better prediction for time series with a narrow range of one point to another as in the time series for Exchange Rates. On the contrary, Exponential Smoothing Method can produce a better forecasting for Exchange Rates that has a narrow range of one point to another for its time series, while itcannot produce a better prediction for a longer forecasting period.

  8. COMPARISON OF CLASSICAL AND INTERACTIVE MULTI-ROBOT EXPLORATION STRATEGIES IN POPULATED ENVIRONMENTS

    Directory of Open Access Journals (Sweden)

    Nassim Kalde

    2015-06-01

    Full Text Available Multi-robot exploration consists in coordinating robots for mapping an unknown environment. It raises several issues concerning task allocation, robot control, path planning and communication. We study exploration in populated environments, in which pedestrian flows can severely impact performances. However, humans have adaptive skills for taking advantage of these flows while moving. Therefore, in order to exploit these human abilities, we propose a novel exploration strategy that explicitly allows for human-robot interactions. Our model for exploration in populated environments combines the classical frontier-based strategy with our interactive approach. We implement interactions where robots can locally choose a human guide to follow and define a parametric heuristic to balance interaction and frontier assignments. Finally, we evaluate to which extent human presence impacts our exploration model in terms of coverage ratio, travelled distance and elapsed time to completion.

  9. Modelling the interaction between bacteriophages and their bacterial hosts.

    Science.gov (United States)

    Beke, Gabor; Stano, Matej; Klucar, Lubos

    2016-09-01

    A mathematical model simulating the interaction between bacteriophages and their bacterial hosts has been developed. It is based on other known models describing this type of interaction, enhanced with an ability to model the system influenced by other environmental factor such as pH and temperature. This could be used for numerous estimations of growth rate, when the pH and/or the temperature of the environment are not constant. The change of pH or the temperature greatly affects the specific growth rate which has an effect on the final results of the simulation. Since the model aims on practical application and easy accessibility, an interactive website has been developed where users can run simulations with their own parameters and easily calculate and visualise the result of simulation. The web simulation is accessible at the URL http://www.phisite.org/model.

  10. Interaction field modeling of mini-UAV swarm

    Science.gov (United States)

    Liou, William W.; Ro, Kapseong; Szu, Harold

    2006-05-01

    A behavior-based, simple interaction model inspired by molecular interaction field depicted by the Lennard-Jones function is examined for the averaged interaction in swarming. The modeled kinematic equation of motion contains only one variable, instead of a multiple state variable dependence a more complete dynamics entails. The model assumes a spatial distribution of the potential associate with the swarm. The model has been applied to examine the formation of swarm and the results are reported. The modeling can be reflected in an equilibrium theory for the operation of a swarm of mini-UAVs pioneered by Szu, where every member serves the mission while exploiting other's loss, resulting in a zero-sum game among the team members.

  11. A simple probabilistic model of multibody interactions in proteins

    DEFF Research Database (Denmark)

    Johansson, Kristoffer Enøe; Hamelryck, Thomas

    2013-01-01

    predictions. Our coarse-grained model is compared to state-of-art methods that use full atomic detail. This article illustrates how the use of simple probabilistic models can lead to new opportunities in the treatment of nonlocal interactions in knowledge-based protein structure prediction and design....... beyond pairwise interactions have been described, the formulation of a general multibody potential is seen as intractable due to the perceived limited amount of data. In this article, we show that it is possible to formulate a probabilistic model of higher order interactions in proteins, without...... arbitrarily limiting the number of contacts. The success of this approach is based on replacing a naive table-based approach with a simple hierarchical model involving suitable probability distributions and conditional independence assumptions. The model captures the joint probability distribution of an amino...

  12. A comparison of model view controller and model view presenter

    OpenAIRE

    Qureshi, M. Rizwan Jameel; Sabir, Fatima

    2014-01-01

    Web application frameworks are managed by using different design strategies. Design strategies are applied by using different design processes. In each design process, requirement specifications are changed in to different design model that describe the detail of different data structure, system architecture, interface and components. Web application frame work is implemented by using Model View Controller (MVC) and Model View Presenter (MVP). These web application models are used to provide ...

  13. Ordering in Two-Dimensional Ising Models with Competing Interactions

    OpenAIRE

    2004-01-01

    We study the 2D Ising model on a square lattice with additional non-equal diagonal next-nearest neighbor interactions. The cases of classical and quantum (transverse) models are considered. Possible phases and their locations in the space of three Ising couplings are analyzed. In particular, incommensurate phases occurring only at non-equal diagonal couplings, are predicted. We also analyze a spin-pseudospin model comprised of the quantum Ising model coupled to XY spin chains in a particular ...

  14. Modeling human dynamics of face-to-face interaction networks

    CERN Document Server

    Starnini, Michele; Pastor-Satorras, Romualdo

    2013-01-01

    Face-to-face interaction networks describe social interactions in human gatherings, and are the substrate for processes such as epidemic spreading and gossip propagation. The bursty nature of human behavior characterizes many aspects of empirical data, such as the distribution of conversation lengths, of conversations per person, or of inter-conversation times. Despite several recent attempts, a general theoretical understanding of the global picture emerging from data is still lacking. Here we present a simple model that reproduces quantitatively most of the relevant features of empirical face-to-face interaction networks. The model describes agents which perform a random walk in a two dimensional space and are characterized by an attractiveness whose effect is to slow down the motion of people around them. The proposed framework sheds light on the dynamics of human interactions and can improve the modeling of dynamical processes taking place on the ensuing dynamical social networks.

  15. Motion Model Employment using interacting Motion Model Algorithm

    DEFF Research Database (Denmark)

    Hussain, Dil Muhammad Akbar

    2006-01-01

    model being correct is computed through a likelihood function for each model.  The study presented a simple technique to introduce additional models into the system using deterministic acceleration which basically defines the dynamics of the system.  Therefore, based on this value more motion models can...... be employed to increase the coverage.  Finally, the combined estimate is obtained using posteriori probabilities from different filter models.   The implemented approach provides an adaptive scheme for selecting various number of motion models.  Motion model description is important as it defines the kind...

  16. Computational Comparison of the Interaction of a Lateral Jet on a Supersonic Generic Missile

    OpenAIRE

    Gnemmi, Patrick; Adeli, Reza; Longo, José Maria

    2008-01-01

    The paper deals with the comparison of computations made at DLR and ISL on the interaction between a lateral jet issuing from a generic missile body and the oncoming supersonic cross-flow. Steady-state numerical simulations are carried out by 3D, viscous, turbulent, Reynolds-Averaged Navier-Stokes Codes; at DLR, a hybrid mesh is used for the TAU calculation, whereas at ISL a hexahedral mesh is used for the CFX computation. Experimental data acquired in the DLR wind tunnel TMK in Cologne act a...

  17. Shock Particle Interaction - Fully Resolved Simulations and Modeling

    Science.gov (United States)

    Mehta, Yash; Neal, Chris; Jackson, Thomas L.; Balachandar, S. "Bala"; Thakur, Siddharth

    2016-11-01

    Currently there is a substantial lack of fully resolved data for shock interacting with multiple particles. In this talk we will fill this gap by presenting results of shock interaction with 1-D array and 3-D structured arrays of particles. Objectives of performing fully resolved simulations of shock propagation through packs of multiple particles are twofold, 1) To understand the complicated physical phenomena occurring during shock particle interaction, and 2) To translate the knowledge from microscale simulations in building next generation point-particle models for macroscale simulations that can better predict the motion (forces) and heat transfer for particles. We compare results from multiple particle simulations against the single particle simulations and make relevant observations. The drag history and flow field for multiple particle simulations are markedly different from those of single particle simluations, highlighting the effect of neighboring particles. We propose new models which capture this effect of neighboring particles. These models are called Pair-wise Interaction Extended Point Particle models (PIEP). Effect of multiple neighboring particles is broken down into pair-wise interactions, and these pair-wise interactions are superimposed to get the final model U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, under Contract No. DE-NA0002378.

  18. MODELING OF THE TRACK AND ROLLING STOCK INTERACTION

    Directory of Open Access Journals (Sweden)

    N. V. Khalipova

    2013-09-01

    Full Text Available Purpose. Interaction of system’s elements of "carriage–track" modelling requires consideration of various criteria, it also requires analysis of many uncertainty and randomness factors’ influence on the basic parameters to ensure optimal or rational parameters of the system. The researching of interactions’ process requires new theoretical approaches to formulation of objectives, based on a generalization of existing modeling approaches. The purpose of this work is development of interaction models between track and rolling stock based on multiple structures of objects. Methodology. Dedicated and formed the main evaluation criteria of dynamic interaction between track and rolling stock optimization - quality assurance and safety of transportation process, improving of their efficiency and reducing of prime cost’s. Based on vector optimization methods, proposed model of rolling stock and track’s elements interaction. For the synthesis of the model used mathematical machine of multiple objects structures. Findings. Generalized approaches to modeling in the interaction of rolling stock and track for different structural elements of the system under different exploitation conditions. This theoretical approach demonstrated on the examples of modeling of passenger and freight cars with track under different exploitation conditions. Originality. Proposed theoretical approach to the problem of track and rolling stock interaction, based on a synthesis of existing models by using of multiple objects structures. Practical value. Using of proposed model allows to structure key data and rational parameters of rolling stock and track interaction’s modeling and to formulate optimal and rational parameters of the system, to determine the effective exploitation parameters and measurement system for rational use of infrastructure.

  19. Interactive Model-Centric Systems Engineering (IMCSE) Phase Two

    Science.gov (United States)

    2015-02-28

    implementation uses a 8 MongoDB/Express/Node.js stack to provide remote model execution and services to store and query model results. Front - end user...the design is on the Pareto Front , across all epochs. 105 Smaling, R., “ Fuzzy Pareto Frontiers in Multidisciplinary System Architecture Analysis...Comparison of benefit versus cost tradespaces with compromise, promising, and fuzzy joint designs indicated

  20. A comparison of food crispness based on the cloud model.

    Science.gov (United States)

    Wang, Minghui; Sun, Yonghai; Hou, Jumin; Wang, Xia; Bai, Xue; Wu, Chunhui; Yu, Libo; Yang, Jie

    2017-08-23

    The cloud model is a typical model which transforms the qualitative concept into the quantitative description. The cloud model has been used less extensively in texture studies before. The purpose of this study was to apply the cloud model in food crispness comparison. The acoustic signals of carrots, white radishes, potatoes, Fuji apples, and crystal pears were recorded during compression. And three time-domain signal characteristics were extracted, including sound intensity, maximum short-time frame energy, and waveform index. The three signal characteristics and the cloud model were used to compare the crispness of the samples mentioned above. The crispness based on the Ex value of the cloud model, in a descending order, was carrot > potato > white radish > Fuji apple > crystal pear. To verify the results of the acoustic signals, mechanical measurement and sensory evaluation were conducted. The results of the two verification experiments confirmed the feasibility of the cloud model. The microstructures of the five samples were also analyzed. The microstructure parameters were negatively related with crispness (p cloud model method can be used for crispness comparison of different kinds of foods. The method is more accurate than the traditional methods such as mechanical measurement and sensory evaluation. The cloud model method can also be applied to other texture studies extensively. © 2017 Wiley Periodicals, Inc.

  1. Model comparison for the density structure along solar prominence threads

    CERN Document Server

    Arregui, I

    2015-01-01

    Quiescent solar prominence fine structures are typically modelled as density enhancements, called threads, which occupy a fraction of a longer magnetic flux tube. The profile of the mass density along the magnetic field is however unknown and several arbitrary alternatives are employed in prominence wave studies. We present a comparison of theoretical models for the field-aligned density along prominence fine structures. We consider Lorentzian, Gaussian, and parabolic profiles. We compare their theoretical predictions for the period ratio between the fundamental transverse kink mode and the first overtone to obtain estimates for the ratio of densities between the central part of the tube and its foot-points and to assess which one would better explain observed period ratio data. Bayesian parameter inference and model comparison techniques are developed and applied. Parameter inference requires the computation of the posterior distribution for the density gradient parameter conditional on the observable period...

  2. A Comparison of Approximation Modeling Techniques: Polynomial Versus Interpolating Models

    Science.gov (United States)

    Giunta, Anthony A.; Watson, Layne T.

    1998-01-01

    Two methods of creating approximation models are compared through the calculation of the modeling accuracy on test problems involving one, five, and ten independent variables. Here, the test problems are representative of the modeling challenges typically encountered in realistic engineering optimization problems. The first approximation model is a quadratic polynomial created using the method of least squares. This type of polynomial model has seen considerable use in recent engineering optimization studies due to its computational simplicity and ease of use. However, quadratic polynomial models may be of limited accuracy when the response data to be modeled have multiple local extrema. The second approximation model employs an interpolation scheme known as kriging developed in the fields of spatial statistics and geostatistics. This class of interpolating model has the flexibility to model response data with multiple local extrema. However, this flexibility is obtained at an increase in computational expense and a decrease in ease of use. The intent of this study is to provide an initial exploration of the accuracy and modeling capabilities of these two approximation methods.

  3. Kinetic models comparison for steam gasification of coal/biomass blend chars.

    Science.gov (United States)

    Xu, Chaofen; Hu, Song; Xiang, Jun; Yang, Haiping; Sun, Lushi; Su, Sheng; Wang, Baowen; Chen, Qindong; He, Limo

    2014-11-01

    The non-isothermal thermogravimetric method (TGA) was applied to different chars produced from lignite (LN), sawdust (SD) and their blends at the different mass ratios in order to investigate their thermal reactivity under steam atmosphere. Through TGA analysis, it was determined that the most prominent interaction between sawdust and lignite occurred at the mass ratio of sawdust/lignite as 1:4, but with further dose of more sawdust into its blends with lignite, the positive interaction deteriorated due to the agglomeration and deactivation of the alkali mineral involved in sawdust at high steam gasification temperature. Through systematic comparison, it could be observed that the random pore model was the most suitable among the three gas-solid reaction models adopted in this research. Finally, rational kinetic parameters were reached from these gas-solid reaction models, which provided a basis for design and operation of the realistic system of co-gasification of lignite and sawdust in this research.

  4. COTHERM: Modelling fluid-rock interactions in Icelandic geothermal systems

    Science.gov (United States)

    Thien, Bruno; Kosakowski, Georg; Kulik, Dmitrii

    2014-05-01

    Mineralogical alteration of reservoir rocks, driven by fluid circulation in natural or enhanced geothermal systems, is likely to influence the long-term performance of geothermal power generation. A key factor is the change of porosity due to dissolution of primary minerals and precipitation of secondary phases. Porosity changes will affect fluid circulation and solute transport, which, in turn, influence mineralogical alteration. This study is part of the Sinergia COTHERM project (COmbined hydrological, geochemical and geophysical modeling of geotTHERMal systems) that is an integrative research project aimed at improving our understanding of the sub-surface processes in magmatically-driven natural geothermal systems. We model the mineralogical and porosity evolution of Icelandic geothermal systems with 1D and 2D reactive transport models. These geothermal systems are typically high enthalphy systems where a magmatic pluton is located at a few kilometers depth. The shallow plutons increase the geothermal gradient and trigger the circulation of hydrothermal waters with a steam cap forming at shallow depth. We investigate two contrasting geothermal systems: Krafla, for which the water recharge consists of meteoritic water; and Reykjanes, for which the water recharge mainly consists of seawater. The initial rock composition is a fresh basalt. We use the GEM-Selektor geochemical modeling package [1] for calculation of kinetically controlled mineral equilibria between the rock and the ingression water. We consider basalt minerals dissolution kinetics according to Palandri & Kharaka [2]. Reactive surface areas are assumed to be geometric surface areas, and are corrected using a spherical-particle surface/mass relationship. For secondary minerals, we consider the partial equilibrium assuming that the primary mineral dissolution is slow, and the secondary mineral precipitation is fast. Comparison of our modeling results with the mineralogical assemblages observed in the

  5. Modeling cardiac β-adrenergic signaling with normalized-Hill differential equations: comparison with a biochemical model

    Directory of Open Access Journals (Sweden)

    Saucerman Jeffrey J

    2010-11-01

    Full Text Available Abstract Background New approaches are needed for large-scale predictive modeling of cellular signaling networks. While mass action and enzyme kinetic approaches require extensive biochemical data, current logic-based approaches are used primarily for qualitative predictions and have lacked direct quantitative comparison with biochemical models. Results We developed a logic-based differential equation modeling approach for cell signaling networks based on normalized Hill activation/inhibition functions controlled by logical AND and OR operators to characterize signaling crosstalk. Using this approach, we modeled the cardiac β1-adrenergic signaling network, including 36 reactions and 25 species. Direct comparison of this model to an extensively characterized and validated biochemical model of the same network revealed that the new model gave reasonably accurate predictions of key network properties, even with default parameters. Normalized Hill functions improved quantitative predictions of global functional relationships compared with prior logic-based approaches. Comprehensive sensitivity analysis revealed the significant role of PKA negative feedback on upstream signaling and the importance of phosphodiesterases as key negative regulators of the network. The model was then extended to incorporate recently identified protein interaction data involving integrin-mediated mechanotransduction. Conclusions The normalized-Hill differential equation modeling approach allows quantitative prediction of network functional relationships and dynamics, even in systems with limited biochemical data.

  6. Power law cosmology model comparison with CMB scale information

    CERN Document Server

    Tutusaus, Isaac; Blanchard, Alain; Dupays, Arnaud; Zolnierowski, Yves; Cohen-Tanugi, Johann; Ealet, Anne; Escoffier, Stéphanie; Fèvre, Olivier Le; Ilić, Stéphane; Piazza, Federico; Pisani, Alice; Plaszczynski, Stéphane; Sakr, Ziad; Salvatelli, Valentina; Schücker, Thomas; Tilquin, André; Virey, Jean-Marc

    2016-01-01

    Despite the ability of the cosmological concordance model ($\\Lambda$CDM) to describe the cosmological observations exceedingly well, power law expansion of the Universe scale radius has been proposed as an alternative framework. We examine here these models, analyzing their ability to fit cosmological data using robust model comparison criteria. Type Ia supernovae (SNIa), baryonic acoustic oscillations (BAO) and acoustic scale information from the cosmic microwave background (CMB) have been used. We find that SNIa data either alone or combined with BAO, can be well reproduced by both $\\Lambda$CDM and power law expansion models with $n \\sim 1.5$, while the constant expansion rate model ($n = 1$) is clearly disfavored. Allowing for some redshift evolution in the SNIa luminosity essentially removes any clear preference for a specific model. The CMB data is well known to provide the most stringent constraints on standard cosmological models, in particular through the position of the first peak of the temperature ...

  7. Comparison of four different models of vortex generators

    DEFF Research Database (Denmark)

    Fernandez, U.; Réthoré, Pierre-Elouan; Sørensen, Niels N.

    2012-01-01

    A detailed comparison between four different models of vortex generators is presented in this paper. To that end, a single Vortex Generator on a flat plate test case has been designed and solved by the following models. The first one is the traditional mesh-resolved VG and the second one, called...... Actuator Vortex Generator Model (AcVG), is based on the lifting force theory of Bender, Anderson and Yagle, the BAY Model, which provides an efficient method for computational fluid dynamic (CFD) simulations of flow with VGs, and the forces are applied into the computational domain using the actuator shape...... model. This AcVG Model enables to simulate the effects of the Vortex Generators without defining the geometry of the vortex generator in the mesh and makes it easier for researchers the investigations of different vortex generator lay outs. Both models have been archived by the in house EllipSys CFD...

  8. Numerically exact dynamics of the interacting many-body Schroedinger equation for Bose-Einstein condensates. Comparison to Bose-Hubbard and Gross-Pitaevskii theory

    Energy Technology Data Exchange (ETDEWEB)

    Sakmann, Kaspar

    2010-07-21

    In this thesis, the physics of trapped, interacting Bose-Einstein condensates is analyzed by solving the many-body Schroedinger equation. Particular emphasis is put on coherence, fragmentation and reduced density matrices. First, the ground state of a trapped Bose-Einstein condensate and its correlation functions are obtained. Then the dynamics of a bosonic Josephson junction is investigated by solving the time-dependent many-body Schroedinger equation numerically exactly. These are the first exact results in literature in this context. It is shown that the standard approximations of the field, Gross-Pitaevskii theory and the Bose-Hubbard model fail at weak interaction strength and within their range of expected validity. For stronger interactions the dynamics becomes strongly correlated and a new equilibration phenomenon is discovered. By comparison with exact results it is shown that a symmetry of the Bose- Hubbard model between attractive and repulsive interactions must be considered an artefact of the model. A conceptual innovation of this thesis are time-dependent Wannier functions. Equations of motion for time-dependent Wannier functions are derived from the variational principle. By comparison with exact results it is shown that lattice models can be greatly improved at little computational cost by letting the Wannier functions of a lattice model become time-dependent. (orig.)

  9. Distinguishing interactions in 3-form dark energy models

    CERN Document Server

    Morais, João; Kumar, K Sravan; Marto, João; Tavakoli, Yaser

    2016-01-01

    In this paper we consider 3-form dark energy (DE) models with interactions in the dark sector. We aim to distinguish the phenomenological interactions that are defined through the dark matter (DM) and the DE energy densities. We do our analysis mainly in two stages. In the first stage, we identify the non-interacting 3-form DE model which generically leads to an abrupt late-time cosmological event which is known as the little sibling of the Big Rip (LSBR). We classify the interactions which can possibly avoid this late-time abrupt event. We also study the parameter space of the model that is consistent with the interaction between DM and DE energy densities at present as indicated by recent studies based on BAO and SDSS data. In the later stage, we observationally distinguish those interactions using the statefinder hierarchy parameters $\\{ S_{3}^{(1)}\\,,\\, S_{4}^{(1)}\\} \\,,\\,\\{ S_{3}^{(1)}\\,,\\, S_{5}^{(1)}\\} .$ We also compute the growth factor parameter $\\epsilon(z)$ for the various interactions we consider...

  10. Coarse-grain modelling of protein-protein interactions

    NARCIS (Netherlands)

    Baaden, Marc; Marrink, Siewert J.

    2013-01-01

    Here, we review recent advances towards the modelling of protein-protein interactions (PPI) at the coarse-grained (CG) level, a technique that is now widely used to understand protein affinity, aggregation and self-assembly behaviour. PPI models of soluble proteins and membrane proteins are separate

  11. Evaluating Differential Effects Using Regression Interactions and Regression Mixture Models

    Science.gov (United States)

    Van Horn, M. Lee; Jaki, Thomas; Masyn, Katherine; Howe, George; Feaster, Daniel J.; Lamont, Andrea E.; George, Melissa R. W.; Kim, Minjung

    2015-01-01

    Research increasingly emphasizes understanding differential effects. This article focuses on understanding regression mixture models, which are relatively new statistical methods for assessing differential effects by comparing results to using an interactive term in linear regression. The research questions which each model answers, their…

  12. Reduced-order models for vertical human-structure interaction

    Science.gov (United States)

    Van Nimmen, Katrien; Lombaert, Geert; De Roeck, Guido; Van den Broeck, Peter

    2016-09-01

    For slender and lightweight structures, the vibration serviceability under crowd- induced loading is often critical in design. Currently, designers rely on equivalent load models, upscaled from single-person force measurements. Furthermore, it is important to consider the mechanical interaction with the human body as this can significantly reduce the structural response. To account for these interaction effects, the contact force between the pedestrian and the structure can be modelled as the superposition of the force induced by the pedestrian on a rigid floor and the force resulting from the mechanical interaction between the structure and the human body. For the case of large crowds, however, this approach leads to models with a very high system order. In the present contribution, two equivalent reduced-order models are proposed to approximate the dynamic behaviour of the full-order coupled crowd-structure system. A numerical study is performed to evaluate the impact of the modelling assumptions on the structural response to pedestrian excitation. The results show that the full-order moving crowd model can be well approximated by a reduced-order model whereby the interaction with the pedestrians in the crowd is modelled using a single (equivalent) SDOF system.

  13. A dipole interaction model for the molecular second hyperpolarizability

    NARCIS (Netherlands)

    Jensen, L; Sylvester-Hvid, KO; Mikkelsen, KV; Astrand, PO

    2003-01-01

    A dipole interaction model (IM) for calculating the molecular second hyperpolarizability, gamma, of aliphatic and aromatic molecules has been investigated. The model has been parametrized from quantum chemical calculations of gamma at the self-consistent field (SCF) level of theory for 72 molecules.

  14. Time-Limited Psychotherapy: An Interactional Stage Model.

    Science.gov (United States)

    Tracey, Terence J.

    One model of successful time-limited psychotherapy characterizes the therapy as a movement through three interactional stages: the early rapport attainment stage, the middle conflict stage, and the final resolution stage. According to this model, these stages are indicated by the relative presence of communicational harmony. To examine the…

  15. Cluster variation studies of the anisotropic exchange interaction model

    Science.gov (United States)

    King, T. C.; Chen, H. H.

    The cluster variation method is applied to study critical properties of the Potts-like ferromagnetic anisotropic exchange interaction model. Phase transition temperatures, order parameter discontinuities and latent heats of the model on the triangular and the fcc lattices are determined by the triangle approximation; and those on the square and the sc lattices are determined by the square approximation.

  16. ETP Modelling. Intuitive User interaction. Overview 2011-2014

    NARCIS (Netherlands)

    Erp, J.B.F. van; Maanen, P.P. van; Venrooij, W.; Calvert, S.C.; Beurden, M.H.P.H. van

    2014-01-01

    Intuitive User Interaction aims to develop the next generation user interfaces required to grant experts and laymen access to complex models and large amount of data in design and decision processes and therewith to contribute to the ambition to broaden the applicability of models. Important topics

  17. The Interacting Boson Model for Anomalous Rotational Bands

    Institute of Scientific and Technical Information of China (English)

    QIAN Cheng-De; LIU Dang-Bo; HE Wei

    2002-01-01

    The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.

  18. Interactive Coherence-Based Façade Modeling

    KAUST Repository

    Musialski, Przemyslaw

    2012-05-01

    We propose a novel interactive framework for modeling building facades from images. Our method is based on the notion of coherence-based editing which allows exploiting partial symmetries across the facade at any level of detail. The proposed workflow mixes manual interaction with automatic splitting and grouping operations based on unsupervised cluster analysis. In contrast to previous work, our approach leads to detailed 3d geometric models with up to several thousand regions per facade. We compare our modeling scheme to others and evaluate our approach in a user study with an experienced user and several novice users.

  19. Submillimeter Absorption Spectroscopy in Semiconductor Manufacturing Plasmas and Comparison to Theoretical Models

    Science.gov (United States)

    Helal, Yaser H.; Neese, Christopher F.; De Lucia, Frank C.; Ewing, Paul R.; Agarwal, Ankur; Craver, Barry; Stout, Phillip J.; Armacost, Michael D.

    2015-06-01

    Plasmas used in the semiconductor manufacturing industry are of a similar nature to the environments often created for submillimeter spectroscopic study of astrophysical species. At the low operating pressures of these plasmas, submillimeter absorption spectroscopy is a method capable of measuring the abundances and temperatures of molecules, radicals, and ions without disturbing any of the properties of the plasma. These measurements provide details and insight into the interactions and reactions occurring within the plasma and their implications for semiconductor manufacturing processes. A continuous wave, 500 to 750 GHz, absorption spectrometer was designed and used to make measurements of species in semiconductor processing plasmas. Comparisons with expectations from theoretical plasma models provide a basis for validating and improving these models, which is a complex and difficult science itself. Furthermore, these comparisons are an evaluation for the use of submillimeter spectroscopy as a diagnostic tool in manufacturing processes.

  20. Hyperon-Nucleon Interaction in a Quark Model

    CERN Document Server

    Oka, M

    1993-01-01

    A lecture given at the International School Seminar on {\\sl Hadrons and Nuclei from QCD}, Tsuruga-Vladivostok-Sapporo, August-September, 1993. A realistic hyperon ($Y$)-nucleon ($N$) interaction based on the quark model and the one-boson-exchange potential is constructed. The Nijmegen potential model D with the SU(3) flavor symmetry is modified with a quark exchange interaction at the short-distance, which replaces the short-range repulsive core in the original model. The flavor-spin dependences of the short-range repulsion are qualitatively different from the original hard-core potential. We also study a two-body weak decay, $\\Lambda N \\to NN$, in the quark model. An effective weak interaction, where one-loop QCD corrections are explicitly taken into account, is employed. Differences from the conventional meson-exchange processes are discussed.

  1. Modeling symbiosis by interactions through species carrying capacities

    Science.gov (United States)

    Yukalov, V. I.; Yukalova, E. P.; Sornette, D.

    2012-08-01

    We introduce a mathematical model of symbiosis between different species by taking into account the influence of each species on the carrying capacities of the others. The modeled entities can pertain to biological and ecological societies or to social, economic and financial societies. Our model includes three basic types: symbiosis with direct mutual interactions, symbiosis with asymmetric interactions, and symbiosis without direct interactions. In all cases, we provide a complete classification of all admissible dynamical regimes. The proposed model of symbiosis turned out to be very rich, as it exhibits four qualitatively different regimes: convergence to stationary states, unbounded exponential growth, finite-time singularity, and finite-time death or extinction of species.

  2. Modeling supercritical fluid extraction process involving solute-solid interaction

    Energy Technology Data Exchange (ETDEWEB)

    Goto, M.; Roy, B. Kodama, A.; Hirose, T. [Kumamoto Univ., Kumamoto (Japan)

    1998-04-01

    Extraction or leaching of solute from natural solid material is a mass transfer process involving dissolution or release of solutes from a solid matrix. Interaction between the solute and solid matrix often influences the supercritical fluid extraction process. A model accounting for the solute-solid interaction as well as mass transfer is developed. The BET equation is used to incorporate the interaction and the solubility of solutes into the local equilibrium in the model. Experimental data for the supercritical extraction of essential oil and cuticular wax from peppermint leaves are successfully analyzed by the model. The effects of parameters on the extraction behavior are demonstrated to illustrate the concept of the model. 18 refs., 5 figs., 1 tab.

  3. Systematic Uncertainties in High-Energy Hadronic Interaction Models

    Science.gov (United States)

    Zha, M.; Knapp, J.; Ostapchenko, S.

    2003-07-01

    Hadronic interaction models for cosmic ray energies are uncertain since our knowledge of hadronic interactions is extrap olated from accelerator experiments at much lower energies. At present most high-energy models are based on Grib ov-Regge theory of multi-Pomeron exchange, which provides a theoretical framework to evaluate cross-sections and particle production. While experimental data constrain some of the model parameters, others are not well determined and are therefore a source of systematic uncertainties. In this paper we evaluate the variation of results obtained with the QGSJET model, when modifying parameters relating to three ma jor sources of uncertainty: the form of the parton structure function, the role of diffractive interactions, and the string hadronisation. Results on inelastic cross sections, on secondary particle production and on the air shower development are discussed.

  4. Integrated Modeling of Groundwater and Surface Water Interactions in a Manmade Wetland

    Directory of Open Access Journals (Sweden)

    Guobiao Huang Gour-Tsyh Yeh

    2012-01-01

    Full Text Available A manmade pilot wetland in south Florida, the Everglades Nutrient Removal (ENR project, was modeled with a physics-based integrated approach using WASH123D (Yeh et al. 2006. Storm water is routed into the treatment wetland for phosphorus removal by plant and sediment uptake. It overlies a highly permeable surficial groundwater aquifer. Strong surface water and groundwater interactions are a key component of the hydrologic processes. The site has extensive field measurement and monitoring tools that provide point scale and distributed data on surface water levels, groundwater levels, and the physical range of hydraulic parameters and hydrologic fluxes. Previous hydrologic and hydrodynamic modeling studies have treated seepage losses empirically by some simple regression equations and, only surface water flows are modeled in detail. Several years of operational data are available and were used in model historical matching and validation. The validity of a diffusion wave approximation for two-dimensional overland flow (in the region with very flat topography was also tested. The uniqueness of this modeling study is notable for (1 the point scale and distributed comparison of model results with observed data; (2 model parameters based on available field test data; and (3 water flows in the study area include two-dimensional overland flow, hydraulic structures/levees, three-dimensional subsurface flow and one-dimensional canal flow and their interactions. This study demonstrates the need and the utility of a physics-based modeling approach for strong surface water and groundwater interactions.

  5. Use of a PhET Interactive Simulation in General Chemistry Laboratory: Models of the Hydrogen Atom

    Science.gov (United States)

    Clark, Ted M.; Chamberlain, Julia M.

    2014-01-01

    An activity supporting the PhET interactive simulation, Models of the Hydrogen Atom, has been designed and used in the laboratory portion of a general chemistry course. This article describes the framework used to successfully accomplish implementation on a large scale. The activity guides students through a comparison and analysis of the six…

  6. Small Current Quark Mass Effects on Dressed-Quark Propagator in an Effective Quark-Quark Interaction Model

    Institute of Scientific and Technical Information of China (English)

    ZONG Hong-Shi; WU Xiao-Hua; SUN Wei-Min; ZHAO En-Guang; WANG Fan

    2003-01-01

    A method for obtaining the smallcurrent quark mass dependence of the dressed quark propagator froman effective quark-quark interaction model is developed. Within this approach the small current quark mass effects ondressed-quark propagator have been studied. A comparison with previous results is given.

  7. Use of a PhET Interactive Simulation in General Chemistry Laboratory: Models of the Hydrogen Atom

    Science.gov (United States)

    Clark, Ted M.; Chamberlain, Julia M.

    2014-01-01

    An activity supporting the PhET interactive simulation, Models of the Hydrogen Atom, has been designed and used in the laboratory portion of a general chemistry course. This article describes the framework used to successfully accomplish implementation on a large scale. The activity guides students through a comparison and analysis of the six…

  8. Comparison of different efficiency criteria for hydrological model assessment

    Directory of Open Access Journals (Sweden)

    P. Krause

    2005-01-01

    Full Text Available The evaluation of hydrologic model behaviour and performance is commonly made and reported through comparisons of simulated and observed variables. Frequently, comparisons are made between simulated and measured streamflow at the catchment outlet. In distributed hydrological modelling approaches, additional comparisons of simulated and observed measurements for multi-response validation may be integrated into the evaluation procedure to assess overall modelling performance. In both approaches, single and multi-response, efficiency criteria are commonly used by hydrologists to provide an objective assessment of the "closeness" of the simulated behaviour to the observed measurements. While there are a few efficiency criteria such as the Nash-Sutcliffe efficiency, coefficient of determination, and index of agreement that are frequently used in hydrologic modeling studies and reported in the literature, there are a large number of other efficiency criteria to choose from. The selection and use of specific efficiency criteria and the interpretation of the results can be a challenge for even the most experienced hydrologist since each criterion may place different emphasis on different types of simulated and observed behaviours. In this paper, the utility of several efficiency criteria is investigated in three examples using a simple observed streamflow hydrograph.

  9. Comparison and evaluation of network clustering algorithms applied to genetic interaction networks.

    Science.gov (United States)

    Hou, Lin; Wang, Lin; Berg, Arthur; Qian, Minping; Zhu, Yunping; Li, Fangting; Deng, Minghua

    2012-01-01

    The goal of network clustering algorithms detect dense clusters in a network, and provide a first step towards the understanding of large scale biological networks. With numerous recent advances in biotechnologies, large-scale genetic interactions are widely available, but there is a limited understanding of which clustering algorithms may be most effective. In order to address this problem, we conducted a systematic study to compare and evaluate six clustering algorithms in analyzing genetic interaction networks, and investigated influencing factors in choosing algorithms. The algorithms considered in this comparison include hierarchical clustering, topological overlap matrix, bi-clustering, Markov clustering, Bayesian discriminant analysis based community detection, and variational Bayes approach to modularity. Both experimentally identified and synthetically constructed networks were used in this comparison. The accuracy of the algorithms is measured by the Jaccard index in comparing predicted gene modules with benchmark gene sets. The results suggest that the choice differs according to the network topology and evaluation criteria. Hierarchical clustering showed to be best at predicting protein complexes; Bayesian discriminant analysis based community detection proved best under epistatic miniarray profile (EMAP) datasets; the variational Bayes approach to modularity was noticeably better than the other algorithms in the genome-scale networks.

  10. COMPARISON BETWEEN MODELS FOR CALCULATION OF INDUSTRIAL HOT ROLLING LOADS

    Directory of Open Access Journals (Sweden)

    Antonio Augusto Gorni

    2012-09-01

    Full Text Available An evaluation is made about the precision of hot strip rolling mill loads at the F1 stand calculated according to the theoretical models of Orowan, Sims, Alexander-Ford, Orowan-Pascoe, Ekelund and Tselikov in comparison to real values got for carbon-manganese steels. In the deterministic approach, without any fit of the calculated values to real data, Orowan, Sims and Alexander-Models show best levels of precision, as expected from the information got in the literature. However, in the semi-empirical approach, after a linear fit between calculated values and real data, Tselikov and Ekelund models show better adequacy to the industrial data, a fact that can be attributed to more significant errors occurring in the sub-models of temperature, tribology and hot strength than in the rolling load models. For its turn, neural network models show the best levels of precision which make very attractive the adoption of this approach.

  11. Interactive Documentary: A Production Model for Nonfiction Multimedia Narratives

    Science.gov (United States)

    Choi, Insook

    This paper presents an interactive production model for nonfiction multimedia, referred to as interactive documentary. We discuss the design of ontologies for authoring interactive documentary. A working prototype supports the use of reasoning for retrieving, composing, and displaying media resources in real-time. A GUI is designed to facilitate concept-based navigation which enables queries across media resources of diverse types. A dual-root-node data design links ontological reasoning with metadata, which provides a method for defining hybrid semantic-quantitative relationships. Our application focuses on archiving and retrieving non-text based media resources. The system architecture supports sensory-rich display feedback with real time interactivity for navigating documents’ space. We argue an experience of narratives evolves through the performitivity in the interactive narrative structure when the constituents are mediated by common ontology. The consequential experience identifies a renewed practice of oral tradition where the accumulative sensorial propositions inform narratives, such as in performance practice.

  12. Comparisons of hadrontherapy-relevant data to nuclear interaction codes in the Geant4 toolkit

    Science.gov (United States)

    Braunn, B.; Boudard, A.; Colin, J.; Cugnon, J.; Cussol, D.; David, J. C.; Kaitaniemi, P.; Labalme, M.; Leray, S.; Mancusi, D.

    2013-03-01

    Comparisons between experimental data, INCL and other nuclear models available in the Geant4 toolkit are presented. The data used for the comparisons come from a fragmentation experiment realised at GANIL facility. The main purpose of this experiment was to measure production rates and angular distributions of emitted particles from the collision of a 95.A MeV 12C beam and thick PMMA (plastic) targets. The latest version of the Intra Nuclear Cascade of Liege code extended to nucleus-nucleus collisions for ion beam therapy application will be described. This code as well as JQMD and the Geant4 binary cascade has been compared with these hadrontherapy-oriented experimental data. The results from the comparisons exhibit an overall qualitative agreement between the models and the experimental data. However, at a quantitative level, it has been shown that none of this three models manage to reproduce precisely all the data. The nucleus-nucleus extension of INCL, which is not predictive enough for ion beam therapy application yet, has nevertheless proven to be competitive with other nuclear collisions codes.

  13. Meson Exchange Current (MEC) Models in Neutrino Interaction Generators

    CERN Document Server

    Katori, Teppei

    2013-01-01

    Understanding of the so-called 2 particle-2 hole (2p-2h) effect is an urgent program in neutrino interaction physics for current and future oscillation experiments. Such processes are believed to be responsible for the event excesses observed by recent neutrino experiments. The 2p-2h effect is dominated by the meson exchange current (MEC), and is accompanied by a 2-nucleon emission from the primary vertex, instead of a single nucleon emission from the charged-current quasi-elastic (CCQE) interaction. Current and future high resolution experiments can potentially nail down this effect. For this reason, there are world wide efforts to model and implement this process in neutrino interaction simulations. In these proceedings, I would like to describe how this channel is modeled in neutrino interaction generators.

  14. Interactive, process-oriented climate modeling with CLIMLAB

    Science.gov (United States)

    Rose, B. E. J.

    2016-12-01

    Global climate is a complex emergent property of the rich interactions between simpler components of the climate system. We build scientific understanding of this system by breaking it down into component process models (e.g. radiation, large-scale dynamics, boundary layer turbulence), understanding each components, and putting them back together. Hands-on experience and freedom to tinker with climate models (whether simple or complex) is invaluable for building physical understanding. CLIMLAB is an open-ended software engine for interactive, process-oriented climate modeling. With CLIMLAB you can interactively mix and match model components, or combine simpler process models together into a more comprehensive model. It was created primarily to support classroom activities, using hands-on modeling to teach fundamentals of climate science at both undergraduate and graduate levels. CLIMLAB is written in Python and ties in with the rich ecosystem of open-source scientific Python tools for numerics and graphics. The Jupyter Notebook format provides an elegant medium for distributing interactive example code. I will give an overview of the current capabilities of CLIMLAB, the curriculum we have developed thus far, and plans for the future. Using CLIMLAB requires some basic Python coding skills. We consider this an educational asset, as we are targeting upper-level undergraduates and Python is an increasingly important language in STEM fields.

  15. The use of MAVIS II to integrate the modeling and analysis of explosive valve interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ng, R.; Kwon, D.M.

    1998-12-31

    The MAVIS II computer program provides for the modeling and analysis of explosive valve interactions. This report describes the individual components of the program and how MAVIS II is used with other available tools to integrate the design and understanding of explosive valves. The rationale and model used for each valve interaction is described. Comparisons of the calculated results with available data have demonstrated the feasibility and accuracy of using MAVIS II for analytical studies of explosive valve interactions. The model used for the explosive or pyrotechnic used as the driving force in explosive valves is the most critical to be understood and modeled. MAVIS II is an advanced version that incorporates a plastic, as well as elastic, modeling of the deformations experienced when plungers are forced into a bore. The inclusion of a plastic model has greatly expanded the use of MAVIS for all categories (opening, closure, or combined) of valves, especially for the closure valves in which the sealing operation requires the plastic deformation of either a plunger or bore over a relatively large area. In order to increase its effectiveness, the use of MAVIS II should be integrated with the results from available experimental hardware. Test hardware such as the Velocity Interferometer System for Any Reflector (VISAR) and Velocity Generator test provide experimental data for accurate comparison of the actual valve functions. Variable Explosive Chamber (VEC) and Constant Explosive Volume (CEV) tests are used to provide the proper explosive equation-of-state for the MAVIS calculations of the explosive driving forces. The rationale and logistics of this integration is demonstrated through an example. A recent valve design is used to demonstrate how MAVIS II can be integrated with experimental tools to provide an understanding of the interactions in this valve.

  16. Hysteresis and creep: Comparison between a power-law model and Kuhnen's model

    Energy Technology Data Exchange (ETDEWEB)

    Oliveri, Alberto; Stellino, Flavio; Parodi, Mauro; Storace, Marco, E-mail: marco.storace@unige.it

    2016-04-01

    In this paper we analyze some properties of a recently proposed model of hysteresis and creep (related to a circuit model, whose only nonlinear element is based on a power law) and compare it with the well-known Kuhnen's model. A first qualitative comparison relies on the analysis of the behavior of the elementary cell of each model. Their responses to step inputs (which allow to better evidence the creep effect) are analyzed and compared. Then, a quantitative comparison is proposed, based on the fitting performances of the two models on experimental data measured from a commercial piezoelectric actuator.

  17. Comparison of fully internally and strongly contracted multireference configuration interaction procedures

    Science.gov (United States)

    Sivalingam, Kantharuban; Krupicka, Martin; Auer, Alexander A.; Neese, Frank

    2016-08-01

    Multireference (MR) methods occupy an important class of approaches in quantum chemistry. In many instances, for example, in studying complex magnetic properties of transition metal complexes, they are actually the only physically satisfactory choice. In traditional MR approaches, single and double excitations are performed with respect to all reference configurations (or configuration state functions, CSFs), which leads to an explosive increase of computational cost for larger reference spaces. This can be avoided by the internal contraction scheme proposed by Meyer and Siegbahn, which effectively reduces the number of wavefunction parameters to their single-reference counterpart. The "fully internally contracted" scheme (FIC) is well known from the popular CASPT2 approach. An even shorter expansion of the wavefunction is possible with the "strong contraction" (SC) scheme proposed by Angeli and Malrieu in their NEVPT2 approach. Promising multireference configuration interaction formulations (MRCI) employing internal contraction and strong contraction have been reported by several authors. In this work, we report on the implementation of the FIC-MRCI and SC-MRCI methodologies, using a computer assisted implementation strategy. The methods are benchmarked against the traditional uncontracted MRCI approach for ground and excited states of small molecules (N2, O2, CO, CO+, OH, CH, and CN). For ground states, the comparison includes the "partially internally contracted" MRCI based on the Celani-Werner ansatz (PC-MRCI). For the three contraction schemes, the average errors range from 2% to 6% of the uncontracted MRCI correlation energies. Excitation energies are reproduced with ˜0.2 eV accuracy. In most cases, the agreement is better than 0.2 eV, even in cases with very large differential correlation contributions as exemplified for the d-d and ligand-to-metal charge transfer transitions of a Cu [NH 3 ] 4 2 + model complex. The benchmark is supplemented with the

  18. Comparison of high-latitude thermospheric meridionalwinds II: combined FPI, radar and model Climatologies

    Directory of Open Access Journals (Sweden)

    E. M. Griffin

    2004-03-01

    Full Text Available The climatological behaviour of the thermospheric meridional wind above Kiruna, Sweden (67.4°N, 20.4°E has been investigated for seasonal and solar cycle dependence using six different techniques, comprising both model and experimental sources. Model output from both the empirical Horizontal Wind Model (HWM (Hedin et al., 1988 and the numerical Coupled Thermosphere and Ionosphere Model (CTIM are compared to the measured behaviour at Kiruna, as a single site example. The empirical International Reference Ionosphere (IRI model is used as input to an implementation of servo theory, to provide another climatology combining empirical input with a theoretical framework. The experimental techniques have been introduced in a companion paper in this issue and provide climatologies from direct measurements, using Fabry-Perot Interferometers (FPI, together with 2 separate techniques applied to the European Incoherent Scatter radar (EISCAT database to derive neutral winds. One of these techniques uses the same implementation of servo theory as has been used with the IRI model. Detailed comparisons for each season and solar activity category allow for conclusions to be drawn as to the major influences on the climatological behaviour of the wind at this latitude. Comparison of the incoherent scatter radar (ISR derived neutral winds with FPI, empirical model and numerical model winds is important to our understanding and judgement of the validity of the techniques used to derive thermospheric wind databases. The comparisons also test model performance and indicate possible reasons for differences found between the models. In turn, the conclusions point to possible improvements in their formulation. In particular it is found that the empirical models are over-reliant on mid-latitude data in their formulation, and fail to provide accurate estimates of the winds at high-latitudes.

    Key words. Meteorology and atmospheric dynamics (thermospheric dynamics

  19. Multinucleon Ejection Model for Two Body Current Neutrino Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Sobczyk, Jan T.; /Fermilab

    2012-06-01

    A model is proposed to describe nucleons ejected from a nucleus as a result of two-body-current neutrino interactions. The model can be easily implemented in Monte Carlo neutrino event generators. Various possibilities to measure the two-body-current contribution are discussed. The model can help identify genuine charge current quasielastic events and allow for a better determination of the systematic error on neutrino energy reconstruction in neutrino oscillation experiments.

  20. A FINITE ELEMENT MODEL FOR SEISMICITY INDUCED BY FAULT INTERACTION

    Institute of Scientific and Technical Information of China (English)

    Chen Huaran; Li Yiqun; He Qiaoyun; Zhang Jieqing; Ma Hongsheng; Li Li

    2003-01-01

    On ths basis of interaction between faults, a finite element model for Southwest China is constructed, and the stress adjustment due to the strong earthquake occurrence in this region was studied. The preliminary results show that many strong earthquakes occurred in the area of increased stress in the model. Though the results are preliminary, the quasi-3D finite element model is meaningful for strong earthquake prediction.

  1. A FINITE ELEMENT MODEL FOR SEISMICITY INDUCED BY FAULT INTERACTION

    Institute of Scientific and Technical Information of China (English)

    ChenHuaran; LiYiqun; HeQiaoyun; ZhangJieqing; MaHongsheng; LiLi

    2003-01-01

    On ths basis of interaction between faults, a finite element model for Southwest China is constructed, and the stress adjustment due to the strong earthquake occurrence in this region was studied. The preliminary results show that many strong earthquakes occurred in the are a of increased stress in the model. Though the results are preliminary, the quasi-3D finite element model is meaningful for strong earthquake prediction.

  2. Interactive Multimedia Synchronization Model Based on Petri Nets

    Institute of Scientific and Technical Information of China (English)

    WANG Zhiqiang; PENG Xiaogang; JI Zhen

    2007-01-01

    The multimedia synchronization is used to coordinate the timing of each multimedia object in the multimedia system.After studying different multimedia synchronization systems that have been published, an Interactive Synchronization multimedia based on Petri Nets model (ISPN) is proposed in this paper. The system is capable of describing the dynamic timing actions of multimedia objects vividly as well as controlling them interactively to maintain the system level synchronization balance.

  3. General quadrupole shapes in the Interacting Boson Model

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A.

    1990-01-01

    Characteristic attributes of nuclear quadrupole shapes are investigated within the algebraic framework of the Interacting Boson Model. For each shape the Hamiltonian is resolved into intrinsic and collective parts, normal modes are identified and intrinsic states are constructed and used to estimate transition matrix elements. Special emphasis is paid to new features (e.g. rigid triaxiality and coexisting deformed shapes) that emerge in the presence of the three-body interactions. 27 refs.

  4. Including lateral interactions into microkinetic models of catalytic reactions

    DEFF Research Database (Denmark)

    Hellman, Anders; Honkala, Johanna Karoliina

    2007-01-01

    In many catalytic reactions lateral interactions between adsorbates are believed to have a strong influence on the reaction rates. We apply a microkinetic model to explore the effect of lateral interactions and how to efficiently take them into account in a simple catalytic reaction. Three differ...... different approximations are investigated: site, mean-field, and quasichemical approximations. The obtained results are compared to accurate Monte Carlo numbers. In the end, we apply the approximations to a real catalytic reaction, namely, ammonia synthesis....

  5. Ξ hypernuclei predicted by the new interaction model ESC08

    Directory of Open Access Journals (Sweden)

    Rijken Th.A.

    2010-04-01

    Full Text Available The features of the new interaction model ESC08 in ΛN , ΣN and ΞN channels are demonstrated by the partial wave contributions to single hyperon potentials UY (Y = Λ, Σ, Ξ in nuclear matter on the basis of the G-matrix theory. Ξ hypernuclei are studied with the ΞN G-matrix interactions derived from ESC08.

  6. Toward immersive clay modeling: interactive modeling with octrees

    Science.gov (United States)

    Moritz, Elke; Kuester, Falko; Hamann, Bernd; Joy, Kenneth I.; Hagen, Hans

    2000-05-01

    The described virtual clay modeling project explores the use of virtual environments (VES) for the simulation of two- handed clay modeling and sculpting tasks. Traditional clay modeling concepts are implemented and enhanced with new digital design tools leveraging from virtual reality (VR) and new input device technology. In particular, the creation of an intuitive and natural work environment for comfortable and unconstrained modeling is emphasized. VR projection devices, such as the Immersive WorkBench, shutter glasses, and pinch gloves, equipped with six-degrees-of-freedom trackers, are used to apply various virtual cutting tools to a volumetric data structure . The employment of an octree as underlying data structure for volume representation and manipulation in immersive environments allows real-time modeling of solids utilizing a suite of either geometrically or mathematically defined cutting and modeling tools.

  7. Modeling of ultrafast THz interactions in molecular crystals

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Clark, Stewart J.; Jepsen, Peter Uhd

    2014-01-01

    In this paper we present a numerical study of terahertz pulses interacting with crystals of cesium iodide. We model the molecular dynamics of the cesium iodide crystals with the Density Functional Theory software CASTEP, where ultrafast terahertz pulses are implemented to the CASTEP software...... to interact with molecular crystals. We investigate the molecular dynamics of cesium iodide crystals when interacting with realistic terahertz pulses of field strengths from 0 to 50 MV/cm. We find nonlinearities in the response of the CsI crystals at field strengths higher than 10 MV/cm....

  8. Comparison of Two Models for Radiative Heat Transfer in High Temperature Thermal Plasmas

    Directory of Open Access Journals (Sweden)

    Matthieu Melot

    2011-01-01

    Full Text Available Numerical simulation of the arc-flow interaction in high-voltage circuit breakers requires a radiation model capable of handling high-temperature participating thermal plasmas. The modeling of the radiative transfer plays a critical role in the overall accuracy of such CFD simulations. As a result of the increase of computational power, CPU intensive methods based on the radiative transfer equation, leading to more accurate results, are now becoming attractive alternatives to current approximate models. In this paper, the predictive capabilities of the finite volume method (RTE-FVM and the P1 model are investigated. A systematic comparison between these two models and analytical solutions are presented for a variety of relevant test cases. Two implementations of each approach are compared, and a critical evaluation is presented.

  9. Estimation of exposure to toxic releases using spatial interaction modeling

    Directory of Open Access Journals (Sweden)

    Conley Jamison F

    2011-03-01

    Full Text Available Abstract Background The United States Environmental Protection Agency's Toxic Release Inventory (TRI data are frequently used to estimate a community's exposure to pollution. However, this estimation process often uses underdeveloped geographic theory. Spatial interaction modeling provides a more realistic approach to this estimation process. This paper uses four sets of data: lung cancer age-adjusted mortality rates from the years 1990 through 2006 inclusive from the National Cancer Institute's Surveillance Epidemiology and End Results (SEER database, TRI releases of carcinogens from 1987 to 1996, covariates associated with lung cancer, and the EPA's Risk-Screening Environmental Indicators (RSEI model. Results The impact of the volume of carcinogenic TRI releases on each county's lung cancer mortality rates was calculated using six spatial interaction functions (containment, buffer, power decay, exponential decay, quadratic decay, and RSEI estimates and evaluated with four multivariate regression methods (linear, generalized linear, spatial lag, and spatial error. Akaike Information Criterion values and P values of spatial interaction terms were computed. The impacts calculated from the interaction models were also mapped. Buffer and quadratic interaction functions had the lowest AIC values (22298 and 22525 respectively, although the gains from including the spatial interaction terms were diminished with spatial error and spatial lag regression. Conclusions The use of different methods for estimating the spatial risk posed by pollution from TRI sites can give different results about the impact of those sites on health outcomes. The most reliable estimates did not always come from the most complex methods.

  10. Evaluation of Aerosol-cloud Interaction in the GISS Model E Using ARM Observations

    Science.gov (United States)

    DeBoer, G.; Bauer, S. E.; Toto, T.; Menon, Surabi; Vogelmann, A. M.

    2013-01-01

    Observations from the US Department of Energy's Atmospheric Radiation Measurement (ARM) program are used to evaluate the ability of the NASA GISS ModelE global climate model in reproducing observed interactions between aerosols and clouds. Included in the evaluation are comparisons of basic meteorology and aerosol properties, droplet activation, effective radius parameterizations, and surface-based evaluations of aerosol-cloud interactions (ACI). Differences between the simulated and observed ACI are generally large, but these differences may result partially from vertical distribution of aerosol in the model, rather than the representation of physical processes governing the interactions between aerosols and clouds. Compared to the current observations, the ModelE often features elevated droplet concentrations for a given aerosol concentration, indicating that the activation parameterizations used may be too aggressive. Additionally, parameterizations for effective radius commonly used in models were tested using ARM observations, and there was no clear superior parameterization for the cases reviewed here. This lack of consensus is demonstrated to result in potentially large, statistically significant differences to surface radiative budgets, should one parameterization be chosen over another.

  11. Distributed hydrological models: comparison between TOPKAPI, a physically based model and TETIS, a conceptually based model

    Science.gov (United States)

    Ortiz, E.; Guna, V.

    2009-04-01

    The present work aims to carry out a comparison between two distributed hydrological models, the TOPKAPI (Ciarapica and Todini, 1998; Todini and Ciarapica, 2001) and TETIS (Vélez, J. J.; Vélez J. I. and Francés, F, 2002) models, obtaining the hydrological solution computed on the basis of the same storm events. The first model is physically based and the second one is conceptually based. The analysis was performed on the 21,4 km2 Goodwin Creek watershed, located in Panola County, Mississippi. This watershed extensively monitored by the Agricultural Research Service (ARS) National Sediment Laboratory (NSL) has been chosen because it offers a complete database compiling precipitation (16 rain gauges), runoff (6 discharge stations) and GIS data. Three storm events were chosen to evaluate the performance of the two models: the first one was chosen to calibrate the models, and the other two to validate them. Both models performed a satisfactory hydrological response both in calibration and validation events. While for the TOPKAPI model it wasn't a real calibration, due to its really good performance with parameters modal values derived of watershed characteristics, for the TETIS model it has been necessary to perform a previous automatic calibration. This calibration was carried out using the data provided by the observed hydrograph, in order to adjust the modeĺs 9 correction factors. Keywords: TETIS, TOPKAPI, distributed models, hydrological response, ungauged basins.

  12. Interaction effects in a microscopic quantum wire model with strong spin-orbit interaction

    Science.gov (United States)

    Winkler, G. W.; Ganahl, M.; Schuricht, D.; Evertz, H. G.; Andergassen, S.

    2017-06-01

    We investigate the effect of strong interactions on the spectral properties of quantum wires with strong Rashba spin-orbit (SO) interaction in a magnetic field, using a combination of matrix product state and bosonization techniques. Quantum wires with strong Rashba SO interaction and magnetic field exhibit a partial gap in one-half of the conducting modes. Such systems have attracted wide-spread experimental and theoretical attention due to their unusual physical properties, among which are spin-dependent transport, or a topological superconducting phase when under the proximity effect of an s-wave superconductor. As a microscopic model for the quantum wire we study an extended Hubbard model with SO interaction and Zeeman field. We obtain spin resolved spectral densities from the real-time evolution of excitations, and calculate the phase diagram. We find that interactions increase the pseudo gap at k = 0 and thus also enhance the Majorana-supporting phase and stabilize the helical spin order. Furthermore, we calculate the optical conductivity and compare it with the low energy spiral Luttinger liquid result, obtained from field theoretical calculations. With interactions, the optical conductivity is dominated by an excotic excitation of a bound soliton-antisoliton pair known as a breather state. We visualize the oscillating motion of the breather state, which could provide the route to their experimental detection in e.g. cold atom experiments.

  13. Comparisons of Air Radiation Model with Shock Tube Measurements

    Science.gov (United States)

    Bose, Deepak; McCorkle, Evan; Bogdanoff, David W.; Allen, Gary A., Jr.

    2009-01-01

    This paper presents an assessment of the predictive capability of shock layer radiation model appropriate for NASA s Orion Crew Exploration Vehicle lunar return entry. A detailed set of spectrally resolved radiation intensity comparisons are made with recently conducted tests in the Electric Arc Shock Tube (EAST) facility at NASA Ames Research Center. The spectral range spanned from vacuum ultraviolet wavelength of 115 nm to infrared wavelength of 1400 nm. The analysis is done for 9.5-10.5 km/s shock passing through room temperature synthetic air at 0.2, 0.3 and 0.7 Torr. The comparisons between model and measurements show discrepancies in the level of background continuum radiation and intensities of atomic lines. Impurities in the EAST facility in the form of carbon bearing species are also modeled to estimate the level of contaminants and their impact on the comparisons. The discrepancies, although large is some cases, exhibit order and consistency. A set of tests and analyses improvements are proposed as forward work plan in order to confirm or reject various proposed reasons for the observed discrepancies.

  14. Combining microsimulation and spatial interaction models for retail location analysis

    Science.gov (United States)

    Nakaya, Tomoki; Fotheringham, A. Stewart; Hanaoka, Kazumasa; Clarke, Graham; Ballas, Dimitris; Yano, Keiji

    2007-12-01

    Although the disaggregation of consumers is crucial in understanding the fragmented markets that are dominant in many developed countries, it is not always straightforward to carry out such disaggregation within conventional retail modelling frameworks due to the limitations of data. In particular, consumer grouping based on sampled data is not assured to link with the other statistics that are vital in estimating sampling biases and missing variables in the sampling survey. To overcome this difficulty, we propose a useful combination of spatial interaction modelling and microsimulation approaches for the reliable estimation of retail interactions based on a sample survey of consumer behaviour being linked with other areal statistics. We demonstrate this approach by building an operational retail interaction model to estimate expenditure flows from households to retail stores in a local city in Japan, Kusatsu City.

  15. Contact Interactions Probe Effective Dark Matter Models at the LHC

    CERN Document Server

    Dreiner, Herbi; Tattersall, Jamie

    2013-01-01

    Effective field theories provide a simple framework for probing possible dark matter (DM) models by reparametrising full interactions into a reduced number of operators with smaller dimensionality in parameter space. In many cases these models have four particle vertices, e.g. qqXX, leading to the pair production of dark matter particles, X, at a hadron collider from initial state quarks, q. In this analysis we show that for many fundamental DM models with s-channel DM couplings to qq-pairs, these effective vertices must also produce quark contact interactions (CI) of the form qqqq. The respective effective couplings are related by the common underlying theory which allows one to translate the upper limits from one coupling to the other. We show that at the LHC, the experimental limits on quark contact interactions give stronger translated limits on the DM coupling than the experimental searches for dark matter pair production.

  16. Developing an Empirical Model for Jet-Surface Interaction Noise

    Science.gov (United States)

    Brown, Clifford A.

    2014-01-01

    The process of developing an empirical model for jet-surface interaction noise is described and the resulting model evaluated. Jet-surface interaction noise is generated when the high-speed engine exhaust from modern tightly integrated or conventional high-bypass ratio engine aircraft strikes or flows over the airframe surfaces. An empirical model based on an existing experimental database is developed for use in preliminary design system level studies where computation speed and range of configurations is valued over absolute accuracy to select the most promising (or eliminate the worst) possible designs. The model developed assumes that the jet-surface interaction noise spectra can be separated from the jet mixing noise and described as a parabolic function with three coefficients: peak amplitude, spectral width, and peak frequency. These coefficients are fit to functions of surface length and distance from the jet lipline to form a characteristic spectra which is then adjusted for changes in jet velocity and/or observer angle using scaling laws from published theoretical and experimental work. The resulting model is then evaluated for its ability to reproduce the characteristic spectra and then for reproducing spectra measured at other jet velocities and observer angles; successes and limitations are discussed considering the complexity of the jet-surface interaction noise versus the desire for a model that is simple to implement and quick to execute.

  17. An Opinion Interactive Model Based on Individual Persuasiveness.

    Science.gov (United States)

    Zhou, Xin; Chen, Bin; Liu, Liang; Ma, Liang; Qiu, Xiaogang

    2015-01-01

    In order to study the formation process of group opinion in real life, we put forward a new opinion interactive model based on Deffuant model and its improved models in this paper because current models of opinion dynamics lack considering individual persuasiveness. Our model has following advantages: firstly persuasiveness is added to individual's attributes reflecting the importance of persuasiveness, which means that all the individuals are different from others; secondly probability is introduced in the course of interaction which simulates the uncertainty of interaction. In Monte Carlo simulation experiments, sensitivity analysis including the influence of randomness, initial persuasiveness distribution, and number of individuals is studied at first; what comes next is that the range of common opinion based on the initial persuasiveness distribution can be predicted. Simulation experiment results show that when the initial values of agents are fixed, no matter how many times independently replicated experiments, the common opinion will converge at a certain point; however the number of iterations will not always be the same; the range of common opinion can be predicted when initial distribution of opinion and persuasiveness are given. As a result, this model can reflect and interpret some phenomena of opinion interaction in realistic society.

  18. Analysing earthquake slip models with the spatial prediction comparison test

    KAUST Repository

    Zhang, L.

    2014-11-10

    Earthquake rupture models inferred from inversions of geophysical and/or geodetic data exhibit remarkable variability due to uncertainties in modelling assumptions, the use of different inversion algorithms, or variations in data selection and data processing. A robust statistical comparison of different rupture models obtained for a single earthquake is needed to quantify the intra-event variability, both for benchmark exercises and for real earthquakes. The same approach may be useful to characterize (dis-)similarities in events that are typically grouped into a common class of events (e.g. moderate-size crustal strike-slip earthquakes or tsunamigenic large subduction earthquakes). For this purpose, we examine the performance of the spatial prediction comparison test (SPCT), a statistical test developed to compare spatial (random) fields by means of a chosen loss function that describes an error relation between a 2-D field (‘model’) and a reference model. We implement and calibrate the SPCT approach for a suite of synthetic 2-D slip distributions, generated as spatial random fields with various characteristics, and then apply the method to results of a benchmark inversion exercise with known solution. We find the SPCT to be sensitive to different spatial correlations lengths, and different heterogeneity levels of the slip distributions. The SPCT approach proves to be a simple and effective tool for ranking the slip models with respect to a reference model.

  19. Off-site interaction effect in the Extended Hubbard Model with the SCRPA method

    Energy Technology Data Exchange (ETDEWEB)

    Harir, S [Laboratoire de Physique de la Matiere Condensee, Faculte des Sciences Ben M' Sik, Universite Hassan II-Mohammedia Casablanca (Morocco); Bennai, M [Laboratoire de Physique de la Matiere Condensee, Faculte des Sciences Ben M' Sik, Universite Hassan II-Mohammedia Casablanca (Morocco); Boughaleb, Y [Laboratoire de Physique de la Matiere Condensee, Faculte des Sciences Ben M' Sik, Universite Hassan II-Mohammedia Casablanca (Morocco)

    2007-10-15

    The self consistent random phase approximation (SCRPA) and a direct analytical (DA) method are proposed to solve the Extended Hubbard Model (EHM) in one dimension (1D). We have considered an EHM including on-site and off-site interactions for closed chains in 1D with periodic boundary conditions. The comparison of the SCRPA results with the ones obtained by a DA approach shows that the SCRPA treats the problem of these closed chains in a rigorous manner. The analysis of the nearest-neighbour repulsion effect on the dynamics of our closed chains shows that this repulsive interaction between the electrons of the neighbouring atoms induces supplementary conductivity, since, the SCRPA energygap vanishes when these closed chains are governed by a strong repulsive on-site interaction and intermediate nearest-neighbour repulsion.

  20. Off-site interaction effect in the Extended Hubbard Model with the SCRPA method

    Science.gov (United States)

    Harir, S.; Bennai, M.; Boughaleb, Y.

    2007-10-01

    The self consistent random phase approximation (SCRPA) and a direct analytical (DA) method are proposed to solve the Extended Hubbard Model (EHM) in one dimension (1D). We have considered an EHM including on-site and off-site interactions for closed chains in 1D with periodic boundary conditions. The comparison of the SCRPA results with the ones obtained by a DA approach shows that the SCRPA treats the problem of these closed chains in a rigorous manner. The analysis of the nearest-neighbour repulsion effect on the dynamics of our closed chains shows that this repulsive interaction between the electrons of the neighbouring atoms induces supplementary conductivity, since, the SCRPA energygap vanishes when these closed chains are governed by a strong repulsive on-site interaction and intermediate nearest-neighbour repulsion.

  1. The Use of Interactional Metadiscourse: A Comparison of Articles on Turkish Education and Literature

    Science.gov (United States)

    Kan, Mustafa Onur

    2016-01-01

    This study aims to determine the use of interactional metadiscourse in articles from the domains of Turkish language and literature. The study employed a descriptive research model to examine 20 articles from the "Mustafa Kemal University Journal of Social Sciences Institute" (all articles were published between 2010 and 2015 and each…

  2. Supermodel - Interactive Ensemble of Low-dimensional Models

    Science.gov (United States)

    Basnarkov, Lasko; Duane, Gregory; Kocarev, Ljupco

    2013-04-01

    The accuracy of numerical weather prediction is steadily increasing due to the advances in different scientific disciplines. One of them aims at understanding the physics that underlies the atmospheric dynamics. Although the basic laws are well known there is large room for improvement in modeling various small scale processes. Currently they are generally parametrized and thus we are facing dozens of atmospheric models that are used in different meteorological centers around the world. The models are based on the same fluid dynamics laws, but generally differ in spatial resolution, parametrisation of the unresolved processes and also in the corresponding parameter values. Another key factor that contributes to the prediction improvement is the increase of the available computational power. As one consequence the grid resolution is getting smaller. As another, the contemporary numerical weather prediction schemes consider combinations of the outputs of the ensembles of models -- different perturbations of the same model or even different models. Considering interactive ensembles- with dynamical exchange of information between models that run simultaneously-is a novel approach toward improving the weather forecast or climate projection. Although flux exchange between different ocean and atmospheric models has some history, coupling different atmospheric models is rather new. The coupling schemes can be different and the first approaches are those that combine corresponding dynamical variables or tendency components. In this work we present an example with an artificial toy model- the Lorenz 96 model-that shares some properties with the atmosphere. As reality (the atmosphere) we consider one Lorenz 96 class III system, while as its imperfect models are taken three class II systems that have different forcing terms. The interactive ensemble has tendencies that are weighted combinations of the individual models' tendencies. The weights are obtained with statistical

  3. Interacting Ghost Dark Energy Model: Dynamical System Analysis

    CERN Document Server

    Golchin, Hanif; Ebrahimi, Esmaeil

    2016-01-01

    We study the impacts of interaction between dark matter and dark energy in the context of ghost dark energy model. Using the dynamical system analysis, we obtain the fixed points of the system for different types of interactions while the universe is filled with radiation, matter (including dark matter and luminous matter) and dark energy components. We consider the stability of the fixed points in details for different cases. In all cases there is an unstable matter dominated epoch and a stable late time dark energy dominated phase. However, we find that adding the linear interaction, the evolution of ghost dark energy model does not contain the radiation dominated epoch in the early times which is a necessary point in any cosmic model. This failure resolved when we add the non-linear interaction to the model. We also find an upper bound for the value of the coupling constant of the interaction between dark matter and dark energy as b < 0.57 . This bound is necessary to have a decelerating and unstable ma...

  4. Priming and substrate quality interactions in soil organic matter models

    Directory of Open Access Journals (Sweden)

    T. Wutzler

    2012-12-01

    Full Text Available Interactions between different qualities of soil organic matter (SOM affecting their turnover are rarely represented in models. In this study we propose three mathematical strategies at different levels of abstraction for representing those interactions. Implementing these strategies into the Introductory Carbon Balance Model (ICBM and applying them to several scenarios of litter input show that the different levels of abstraction are applicable on different time scales. We present a simple one-parameter equation of substrate limitation applicable at decadal time scale that is straightforward to implement into other models of SOM dynamics. We show how substrate quality interactions can explain priming effects, acceleration of turnover times in FACE experiments, and the slowdown of decomposition in long-term bare fallow experiments as an effect of energy limitation of microbial biomass. The mechanisms of those interactions need to be further scrutinized empirically for a more complete understanding. Overall, substrate quality interactions offer a valuable way of understanding and quantitatively modelling SOM dynamics.

  5. Meridional Winds derived from ionosonde measurements: comparison of different models

    Science.gov (United States)

    Katamzi, Zama; Bosco Habarulema, John; Aruliah, Anasuya

    2016-07-01

    Thermospheric meridional winds are derived from ionospheric F2 region peak parameters (i.e. F2 maximum density, NmF2, and F2 peak height, hmF2) obtained using South African ionosonde for solar maximum (2001 and 2014) and solar minimum (2009). The study uses several different techniques and models to investigate the climatology behaviour of the winds in order to understand wind variability over South Africa. Detailed solar cycle, seasonal and diurnal trends will help establish how the winds influence ionospheric behaviour at this latitude. Comparisons of ionosonde derived neutral winds with empirical and numerical models such as the Coupled Middle Atmosphere Thermosphere Model (CMAT2) and Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) are important to understand the validity of theoretical and empirical models.

  6. Comparison of the dipolar magnetic field generated by two Ising-like models

    Science.gov (United States)

    Peqini, Klaudio; Duka, Bejo

    2015-04-01

    We consider two Ising-like models named respectively the "domino" model and the Rikitake disk dynamo model. Both models are based on some collective interactions that can generate a dipolar magnetic field which reproduces the well-known features of the geomagnetic field: the reversals and secular variation (SV). The first model considers the resultant dipolar magnetic field as formed by the superposition of the magnetic fields generated by the dynamo elements called macrospins, while the second one, starting from the two-disk dynamo action, takes in consideration the collective interactions of several disk dynamo elements. We will apply two versions of each model: the short-range and the long-range coupled dynamo elements. We will study the statistical properties of the time series generated by the simulation of all models. The comparison of these results with the paleomagnetic data series and long series of SV enables us to conclude which of these Ising-like models better match with the geomagnetic field time series. Key words: geomagnetic field, domino model, Rikitake disk dynamo, dipolar moment

  7. Ecosystem management via interacting models of political and ecological processes

    Directory of Open Access Journals (Sweden)

    Haas, T. C.

    2004-01-01

    Full Text Available The decision to implement environmental protection options is a political one. Political realities may cause a country to not heed the most persuasive scientific analysis of an ecosystem's future health. A predictive understanding of the political processes that result in ecosystem management decisions may help guide ecosystem management policymaking. To this end, this article develops a stochastic, temporal model of how political processes influence and are influenced by ecosystem processes. This model is realized in a system of interacting influence diagrams that model the decision making of a country's political bodies. These decisions interact with a model of the ecosystem enclosed by the country. As an example, a model for Cheetah (Acinonyx jubatus management in Kenya is constructed and fitted to decision and ecological data.

  8. Probabilistic models of population evolution scaling limits, genealogies and interactions

    CERN Document Server

    Pardoux, Étienne

    2016-01-01

    This expository book presents the mathematical description of evolutionary models of populations subject to interactions (e.g. competition) within the population. The author includes both models of finite populations, and limiting models as the size of the population tends to infinity. The size of the population is described as a random function of time and of the initial population (the ancestors at time 0). The genealogical tree of such a population is given. Most models imply that the population is bound to go extinct in finite time. It is explained when the interaction is strong enough so that the extinction time remains finite, when the ancestral population at time 0 goes to infinity. The material could be used for teaching stochastic processes, together with their applications. Étienne Pardoux is Professor at Aix-Marseille University, working in the field of Stochastic Analysis, stochastic partial differential equations, and probabilistic models in evolutionary biology and population genetics. He obtai...

  9. Modelling biological invasions: species traits, species interactions, and habitat heterogeneity.

    Science.gov (United States)

    Cannas, Sergio A; Marco, Diana E; Páez, Sergio A

    2003-05-01

    In this paper we explore the integration of different factors to understand, predict and control ecological invasions, through a general cellular automaton model especially developed. The model includes life history traits of several species in a modular structure interacting multiple cellular automata. We performed simulations using field values corresponding to the exotic Gleditsia triacanthos and native co-dominant trees in a montane area. Presence of G. triacanthos juvenile bank was a determinant condition for invasion success. Main parameters influencing invasion velocity were mean seed dispersal distance and minimum reproductive age. Seed production had a small influence on the invasion velocity. Velocities predicted by the model agreed well with estimations from field data. Values of population density predicted matched field values closely. The modular structure of the model, the explicit interaction between the invader and the native species, and the simplicity of parameters and transition rules are novel features of the model.

  10. An Empirical Comparison of Joint and Stratified Frameworks for Studying G × E Interactions: Systolic Blood Pressure and Smoking in the CHARGE Gene-Lifestyle Interactions Working Group.

    Science.gov (United States)

    Sung, Yun Ju; Winkler, Thomas W; Manning, Alisa K; Aschard, Hugues; Gudnason, Vilmundur; Harris, Tamara B; Smith, Albert V; Boerwinkle, Eric; Brown, Michael R; Morrison, Alanna C; Fornage, Myriam; Lin, Li-An; Richard, Melissa; Bartz, Traci M; Psaty, Bruce M; Hayward, Caroline; Polasek, Ozren; Marten, Jonathan; Rudan, Igor; Feitosa, Mary F; Kraja, Aldi T; Province, Michael A; Deng, Xuan; Fisher, Virginia A; Zhou, Yanhua; Bielak, Lawrence F; Smith, Jennifer; Huffman, Jennifer E; Padmanabhan, Sandosh; Smith, Blair H; Ding, Jingzhong; Liu, Yongmei; Lohman, Kurt; Bouchard, Claude; Rankinen, Tuomo; Rice, Treva K; Arnett, Donna; Schwander, Karen; Guo, Xiuqing; Palmas, Walter; Rotter, Jerome I; Alfred, Tamuno; Bottinger, Erwin P; Loos, Ruth J F; Amin, Najaf; Franco, Oscar H; van Duijn, Cornelia M; Vojinovic, Dina; Chasman, Daniel I; Ridker, Paul M; Rose, Lynda M; Kardia, Sharon; Zhu, Xiaofeng; Rice, Kenneth; Borecki, Ingrid B; Rao, Dabeeru C; Gauderman, W James; Cupples, L Adrienne

    2016-07-01

    Studying gene-environment (G × E) interactions is important, as they extend our knowledge of the genetic architecture of complex traits and may help to identify novel variants not detected via analysis of main effects alone. The main statistical framework for studying G × E interactions uses a single regression model that includes both the genetic main and G × E interaction effects (the "joint" framework). The alternative "stratified" framework combines results from genetic main-effect analyses carried out separately within the exposed and unexposed groups. Although there have been several investigations using theory and simulation, an empirical comparison of the two frameworks is lacking. Here, we compare the two frameworks using results from genome-wide association studies of systolic blood pressure for 3.2 million low frequency and 6.5 million common variants across 20 cohorts of European ancestry, comprising 79,731 individuals. Our cohorts have sample sizes ranging from 456 to 22,983 and include both family-based and population-based samples. In cohort-specific analyses, the two frameworks provided similar inference for population-based cohorts. The agreement was reduced for family-based cohorts. In meta-analyses, agreement between the two frameworks was less than that observed in cohort-specific analyses, despite the increased sample size. In meta-analyses, agreement depended on (1) the minor allele frequency, (2) inclusion of family-based cohorts in meta-analysis, and (3) filtering scheme. The stratified framework appears to approximate the joint framework well only for common variants in population-based cohorts. We conclude that the joint framework is the preferred approach and should be used to control false positives when dealing with low-frequency variants and/or family-based cohorts.

  11. Bridge aerodynamics and aeroelasticity: A comparison of modeling schemes

    Science.gov (United States)

    Wu, Teng; Kareem, Ahsan

    2013-11-01

    Accurate modeling of wind-induced loads on bridge decks is critical to ensure the functionality and survivability of long-span bridges. Over the last few decades, several schemes have emerged to model bridge behavior under winds from an aerodynamic/aeroelastic perspective. A majority of these schemes rely on the quasi-steady (QS) theory. This paper systematically compares and assesses the efficacy of five analytical models available in the literature with a new model presented herein. These models include: QS theory-based model, corrected QS theory-based model, linearized QS theory-based model, semi-empirical linear model, hybrid model, and the proposed modified hybrid model. The ability of these models to capture fluid memory and nonlinear effects either individually or collectively is examined. In addition, their ability to include the effects of turbulence in the approach flow on the bridge behavior is assessed. All models are compared in a consistent manner by utilizing the time domain approach. The underlying role of each model in capturing the physics of bridge behavior under winds is highlighted and the influence of incoming turbulence and its interaction with the bridge deck is examined. A discussion is included that focuses on a number of critical parameters pivotal to the effectiveness of corresponding models.

  12. Inter-comparison of experimental catchment data and hydrological modelling

    Science.gov (United States)

    Singh, Shailesh Kumar; Ibbitt, Richard; Srinivasan, M. S.; Shankar, Ude

    2017-07-01

    Hydrological models account for the storage, flow of water and water balance in a catchment, including exchanges of water and energy with the ground, atmosphere and oceans. Because of the need to simplify hydrological models, parameters are often included to help with modelling hydrological processes. Generally the parameters of lumped, semi or distributed hydrological models depend on the values estimated at a gauged location, generally at outlet of the catchment (mostly using discharge). In this approach it is hard to judge how well a model represents internal catchment processes of the hydrological cycle as well as also ignoring the spatial heterogeneity of the catchment. The purpose of the paper is to assess, and potentially improve, the ability of a physically-based semi-distributed hydrological model, TopNet, using a spatially and temporally detailed set of field measurements of catchment responses to diverse weather conditions. The TopNet rainfall-runoff model was applied to the Waipara catchment located in the South Island of New Zealand. Observations from field experiments were compared with the simulation results of uncalibrated TopNet model. The total amount of simulated runoff showed reasonable agreement with observations. However, the model overestimated baseflow and underestimated surface flow. The results show that soil moisture variation within the catchment is well represented by the model. However, comparison of the observed water balance with model results show that there is a deficiency in the calculation of evapotranspiration.

  13. Modelling the interaction between flooding events and economic growth

    Science.gov (United States)

    Grames, J.; Prskawetz, A.; Grass, D.; Blöschl, G.

    2015-06-01

    Socio-hydrology describes the interaction between the socio-economy and water. Recent models analyze the interplay of community risk-coping culture, flooding damage and economic growth (Di Baldassarre et al., 2013; Viglione et al., 2014). These models descriptively explain the feedbacks between socio-economic development and natural disasters like floods. Contrary to these descriptive models, our approach develops an optimization model, where the intertemporal decision of an economic agent interacts with the hydrological system. In order to build this first economic growth model describing the interaction between the consumption and investment decisions of an economic agent and the occurrence of flooding events, we transform an existing descriptive stochastic model into an optimal deterministic model. The intermediate step is to formulate and simulate a descriptive deterministic model. We develop a periodic water function to approximate the former discrete stochastic time series of rainfall events. Due to the non-autonomous exogenous periodic rainfall function the long-term path of consumption and investment will be periodic.

  14. Modelling low energy electron interactions for biomedical uses of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Fuss, M; Garcia, G [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones CientIficas (CSIC), Serrano 113-bis, 28006 Madrid (Spain); Munoz, A; Oller, J C [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avenida Complutense 22, 28040 Madrid (Spain); Blanco, F [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, Avenida Complutense s.n., 28040 Madrid (Spain); Limao-Vieira, P [Departamento de Fisica, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Huerga, C; Tellez, M [Hospital Universitario La Paz, paseo de la Castellana 261, 28046 Madrid (Spain); Hubin-Fraskin, M J [Department of Chemistry, University of Liege, 4000 Liege 1 (Belgium); Nixon, K; Brunger, M, E-mail: g.garcia@imaff.cfmac.csic.e [School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia)

    2009-11-15

    Current radiation based medical applications in the field of radiotherapy, radio-diagnostic and radiation protection require modelling single particle interactions at the molecular level. Due to their relevance in radiation damage to biological systems, special attention should be paid to include the effect of low energy secondary electrons. In this study we present a single track simulation procedure for photons and electrons which is based on reliable experimental and theoretical cross section data and the energy loss distribution functions derived from our experiments. The effect of including secondary electron interactions in this model will be discussed.

  15. Sudden interaction quench in the quantum sine-Gordon model

    Energy Technology Data Exchange (ETDEWEB)

    Sabio, Javier [Instituto de Ciencia de Materiales de Madrid (CSIC), Sor Juana Ines de la Cruz 3, E-28049 Madrid (Spain); Kehrein, Stefan, E-mail: javier.sabio@icmm.csic.e [Arnold-Sommerfeld-Center for Theoretical Physics, Center for NanoSciences and Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, Theresienstrasse 37, 80333 Muenchen (Germany)

    2010-05-15

    We study a sudden interaction quench in the weak-coupling regime of the quantum sine-Gordon model. The real time dynamics of the bosonic mode occupation numbers is calculated using the flow equation method. While we cannot prove results for the asymptotic long-time limit, we can establish the existence of an extended regime in time where the mode occupation numbers relax to twice their equilibrium values. This factor two indicates a non-equilibrium distribution and is a universal feature of weak interaction quenches. The weak-coupling quantum sine-Gordon model therefore turns out to be on the borderline between thermalization and non-thermalization.

  16. Constraining interacting dark energy models with latest cosmological observations

    Science.gov (United States)

    Xia, Dong-Mei; Wang, Sai

    2016-11-01

    The local measurement of H0 is in tension with the prediction of Λ cold dark matter model based on the Planck data. This tension may imply that dark energy is strengthened in the late-time Universe. We employ the latest cosmological observations on cosmic microwave background, the baryon acoustic oscillation, large-scale structure, supernovae, H(z) and H0 to constrain several interacting dark energy models. Our results show no significant indications for the interaction between dark energy and dark matter. The H0 tension can be moderately alleviated, but not totally released.

  17. Constraining interacting dark energy models with latest cosmological observations

    CERN Document Server

    Xia, Dong-Mei

    2016-01-01

    The local measurement of $H_0$ is in tension with the prediction of $\\Lambda$CDM model based on the Planck data. This tension may imply that dark energy is strengthened in the late-time Universe. We employ the latest cosmological observations on CMB, BAO, LSS, SNe, $H(z)$ and $H_0$ to constrain several interacting dark energy models. Our results show no significant indications for the interaction between dark energy and dark matter. The $H_0$ tension can be moderately alleviated, but not totally released.

  18. Revisit of the interacting holographic dark energy model after Planck 2015

    CERN Document Server

    Feng, Lu

    2016-01-01

    We investigate the observational constraints on the interacting holographic dark energy model. We consider five typical interacting models with the interaction terms $Q=3\\beta H\\rho_{\\rm{de}}$, $Q=3\\beta H\\rho_{\\rm{c}}$, $Q=3\\beta H(\\rho_{\\rm{de}}+\\rho_{\\rm c})$, $Q=3\\beta H\\sqrt{\\rho_{\\rm{de}}\\rho_{\\rm c}}$, and $Q=3\\beta H\\frac{\\rho_{\\rm{de}}\\rho_{c}}{\\rho_{\\rm{de}}+\\rho_{\\rm c}}$, respectively, where $\\beta$ is a dimensionless coupling constant. The observational data we use in this paper include the JLA compilation of type Ia supernovae data, the Planck 2015 distance priors data of cosmic microwave background observation, the baryon acoustic oscillations measurements, and the Hubble constant direct measurement. We make a comparison for these five interacting holographic dark energy models by employing the information criteria, and we find that, within the framework of holographic dark energy, the $Q=3\\beta H\\frac{\\rho_{\\rm{de}}\\rho_{\\rm c}}{\\rho_{\\rm{ de}}+\\rho_{\\rm c}}$ model is most favored by current d...

  19. The comparison of immobility time in experimental rat swimming models.

    Science.gov (United States)

    Calil, Caroline Morini; Marcondes, Fernanda Klein

    2006-09-27

    Rat swimming models have been used in studies about stress and depression. However, there is no consensus about interpreting immobility (helplessness or adaptation) in the literature. In the present study, immobility time, glucose and glycogen mobilization, corticosterone and the effect of desipramine and diazepam were investigated in two different models: swimming stress and the forced swimming test. Immobility time was lower in swimming stress than in the forced swimming test. Both swimming models increased corticosterone levels in comparison with control animal levels. Moreover, swimming stress induced higher corticosterone levels than the forced swimming test did [F(2,14)=59.52; pswimming stressswimming testswimming stress in comparison with the forced swimming test and control. The immobility time was recorded and measured in another group treated with desipramine and diazepam in two protocols: a single session of forced swimming test or swimming stress and two sessions (pre- and retest) of forced swimming model or swimming stress. Desipramine decreased the immobility time in the forced swimming test in both the single [F(2,25)=20.63; pswimming session, without changes in the swimming stress model. Diazepam increased the immobility time in the swimming stress but not in the forced swimming test during the single [F(2,26)=11.24; p=0.0003] and retest sessions [F(2,38)=4.17; p=0.02]. It was concluded that swimming stress and the forced swimming test induced different behavior, hormonal and metabolic responses and represented different situations to the animal.

  20. A Comparison of Evolutionary Computation Techniques for IIR Model Identification

    Directory of Open Access Journals (Sweden)

    Erik Cuevas

    2014-01-01

    Full Text Available System identification is a complex optimization problem which has recently attracted the attention in the field of science and engineering. In particular, the use of infinite impulse response (IIR models for identification is preferred over their equivalent FIR (finite impulse response models since the former yield more accurate models of physical plants for real world applications. However, IIR structures tend to produce multimodal error surfaces whose cost functions are significantly difficult to minimize. Evolutionary computation techniques (ECT are used to estimate the solution to complex optimization problems. They are often designed to meet the requirements of particular problems because no single optimization algorithm can solve all problems competitively. Therefore, when new algorithms are proposed, their relative efficacies must be appropriately evaluated. Several comparisons among ECT have been reported in the literature. Nevertheless, they suffer from one limitation: their conclusions are based on the performance of popular evolutionary approaches over a set of synthetic functions with exact solutions and well-known behaviors, without considering the application context or including recent developments. This study presents the comparison of various evolutionary computation optimization techniques applied to IIR model identification. Results over several models are presented and statistically validated.

  1. A Model-Model and Data-Model Comparison for the Early Eocene Hydrological Cycle

    Science.gov (United States)

    Carmichael, Matthew J.; Lunt, Daniel J.; Huber, Matthew; Heinemann, Malte; Kiehl, Jeffrey; LeGrande, Allegra; Loptson, Claire A.; Roberts, Chris D.; Sagoo, Navjit; Shields, Christine

    2016-01-01

    A range of proxy observations have recently provided constraints on how Earth's hydrological cycle responded to early Eocene climatic changes. However, comparisons of proxy data to general circulation model (GCM) simulated hydrology are limited and inter-model variability remains poorly characterised. In this work, we undertake an intercomparison of GCM-derived precipitation and P - E distributions within the extended EoMIP ensemble (Eocene Modelling Intercomparison Project; Lunt et al., 2012), which includes previously published early Eocene simulations performed using five GCMs differing in boundary conditions, model structure, and precipitation-relevant parameterisation schemes. We show that an intensified hydrological cycle, manifested in enhanced global precipitation and evaporation rates, is simulated for all Eocene simulations relative to the preindustrial conditions. This is primarily due to elevated atmospheric paleo-CO2, resulting in elevated temperatures, although the effects of differences in paleogeography and ice sheets are also important in some models. For a given CO2 level, globally averaged precipitation rates vary widely between models, largely arising from different simulated surface air temperatures. Models with a similar global sensitivity of precipitation rate to temperature (dP=dT ) display different regional precipitation responses for a given temperature change. Regions that are particularly sensitive to model choice include the South Pacific, tropical Africa, and the Peri-Tethys, which may represent targets for future proxy acquisition. A comparison of early and middle Eocene leaf-fossil-derived precipitation estimates with the GCM output illustrates that GCMs generally underestimate precipitation rates at high latitudes, although a possible seasonal bias of the proxies cannot be excluded. Models which warm these regions, either via elevated CO2 or by varying poorly constrained model parameter values, are most successful in simulating a

  2. Agent-based financial dynamics model from stochastic interacting epidemic system and complexity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yunfan, E-mail: yunfanlu@yeah.net; Wang, Jun; Niu, Hongli

    2015-06-12

    An agent-based financial stock price model is developed and investigated by a stochastic interacting epidemic system, which is one of the statistical physics systems and has been used to model the spread of an epidemic or a forest fire. Numerical and statistical analysis are performed on the simulated returns of the proposed financial model. Complexity properties of the financial time series are explored by calculating the correlation dimension and using the modified multiscale entropy method. In order to verify the rationality of the financial model, the real stock market indexes, Shanghai Composite Index and Shenzhen Component Index, are studied in comparison with the simulation data of the proposed model for the different infectiousness parameters. The empirical research reveals that this financial model can reproduce some important features of the real stock markets. - Highlights: • A new agent-based financial price model is developed by stochastic interacting epidemic system. • The structure of the proposed model allows to simulate the financial dynamics. • Correlation dimension and MMSE are applied to complexity analysis of financial time series. • Empirical results show the rationality of the proposed financial model.

  3. Comparison of induced velocity models for helicopter flight mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.E.; Houston, S.S.

    2002-07-01

    Modeling of rotor-induced velocity receives continued attention in the literature as the rotorcraft community addresses limitations in the fidelity of simulations of helicopter stability, control, and handling qualities. A comparison is presented of results obtained using a rigid-blade rotor-fuselage model configured with two induced velocity models: a conventional, first-order, finite state, dynamic inflow model and a wake model that solves a vorticity transport equation on a computational mesh enclosing the rotorcraft. Differences between the two models are quantified by comparing predictions of trimmed rotor blade flap, lag and feather angles, airframe pitch and roll attitudes, cross-coupling derivatives, response to control inputs, and airframe vibration. Results are presented in the context of measurements taken on a Puma aircraft in steady flight from hover to high speed. More accurate predictions of the cross-coupling derivatives, response to control, and airframe vibration obtained using the vorticity transport model suggest that incorporation of real flowfield effects is important to extending the bandwidth of applicability of helicopter simulation models. Unexpectedly small differences in some of the trim predictions obtained using the two wake models suggest that an overall improvement in simulation fidelity may not be achieved without equivalent attention to the rotor dynamic model. (Author)

  4. Using Virtual Observatories for Data-Model Comparisons

    Science.gov (United States)

    Ridley, A.; de Zeeuw, D.

    2007-12-01

    Global models of the geospace environment allow researchers to better understand how the environment behaves under different conditions. In order to trust whether the model is accurate, it is crucial to compare the model results to data - i.e., validate the model. Also, models are very good at placing measurements into a global context, so the data can be better understood. With the advent of Virtural Observatories, it will become much easier to conduct data-model comparisons. This is because the model results will have similar descriptors as the data, and reside in model repositories (similar to data repositories), allowing the data and the model results to be cross-linked. In this presentation, we will describe our efforts on creating an environment in which data and models can be easily compared. We will provide real-world examples of how this can be used to better understand the geospace environment, and out progress in realizing the goal of creating such an environment.

  5. Model comparison for the density structure along solar prominence threads

    Science.gov (United States)

    Arregui, I.; Soler, R.

    2015-06-01

    Context. Quiescent solar prominence fine structures are typically modelled as density enhancements, called threads, which occupy a fraction of a longer magnetic flux tube. This is justified from the spatial distribution of the imaged plasma emission or absorption of prominences at small spatial scales. The profile of the mass density along the magnetic field is unknown, however, and several arbitrary alternatives are employed in prominence wave studies. The identification and measurement of period ratios from multiple harmonics in standing transverse thread oscillations offer a remote diagnostics method to probe the density variation of these structures. Aims: We present a comparison of theoretical models for the field-aligned density along prominence fine structures. They aim to imitate density distributions in which the plasma is more or less concentrated around the centre of the magnetic flux tube. We consider Lorentzian, Gaussian, and parabolic profiles. We compare theoretical predictions based on these profiles for the period ratio between the fundamental transverse kink mode and the first overtone to obtain estimates for the density ratios between the central part of the tube and its foot-points and to assess which one would better explain observed period ratio data. Methods: Bayesian parameter inference and model comparison techniques were developed and applied. To infer the parameters, we computed the posterior distribution for the density gradient parameter that depends on the observable period ratio. The model comparison involved computing the marginal likelihood as a function of the period ratio to obtain the plausibility of each density model as a function of the observable. We also computed the Bayes factors to quantify the relative evidence for each model, given a period ratio observation. Results: A Lorentzian density profile, with plasma density concentrated around the centre of the tube, seems to offer the most plausible inversion result. A

  6. Towards more accurate isoscapes encouraging results from wine, water and marijuana data/model and model/model comparisons.

    Science.gov (United States)

    West, J. B.; Ehleringer, J. R.; Cerling, T.

    2006-12-01

    Understanding how the biosphere responds to change it at the heart of biogeochemistry, ecology, and other Earth sciences. The dramatic increase in human population and technological capacity over the past 200 years or so has resulted in numerous, simultaneous changes to biosphere structure and function. This, then, has lead to increased urgency in the scientific community to try to understand how systems have already responded to these changes, and how they might do so in the future. Since all biospheric processes exhibit some patchiness or patterns over space, as well as time, we believe that understanding the dynamic interactions between natural systems and human technological manipulations can be improved if these systems are studied in an explicitly spatial context. We present here results of some of our efforts to model the spatial variation in the stable isotope ratios (δ2H and δ18O) of plants over large spatial extents, and how these spatial model predictions compare to spatially explicit data. Stable isotopes trace and record ecological processes and as such, if modeled correctly over Earth's surface allow us insights into changes in biosphere states and processes across spatial scales. The data-model comparisons show good agreement, in spite of the remaining uncertainties (e.g., plant source water isotopic composition). For example, inter-annual changes in climate are recorded in wine stable isotope ratios. Also, a much simpler model of leaf water enrichment driven with spatially continuous global rasters of precipitation and climate normals largely agrees with complex GCM modeling that includes leaf water δ18O. Our results suggest that modeling plant stable isotope ratios across large spatial extents may be done with reasonable accuracy, including over time. These spatial maps, or isoscapes, can now be utilized to help understand spatially distributed data, as well as to help guide future studies designed to understand ecological change across

  7. A simple probabilistic model of multibody interactions in proteins.

    Science.gov (United States)

    Johansson, Kristoffer Enøe; Hamelryck, Thomas

    2013-08-01

    Protein structure prediction methods typically use statistical potentials, which rely on statistics derived from a database of know protein structures. In the vast majority of cases, these potentials involve pairwise distances or contacts between amino acids or atoms. Although some potentials beyond pairwise interactions have been described, the formulation of a general multibody potential is seen as intractable due to the perceived limited amount of data. In this article, we show that it is possible to formulate a probabilistic model of higher order interactions in proteins, without arbitrarily limiting the number of contacts. The success of this approach is based on replacing a naive table-based approach with a simple hierarchical model involving suitable probability distributions and conditional independence assumptions. The model captures the joint probability distribution of an amino acid and its neighbors, local structure and solvent exposure. We show that this model can be used to approximate the conditional probability distribution of an amino acid sequence given a structure using a pseudo-likelihood approach. We verify the model by decoy recognition and site-specific amino acid predictions. Our coarse-grained model is compared to state-of-art methods that use full atomic detail. This article illustrates how the use of simple probabilistic models can lead to new opportunities in the treatment of nonlocal interactions in knowledge-based protein structure prediction and design. Copyright © 2013 Wiley Periodicals, Inc., a Wiley company.

  8. Comparison of activity coefficient models for atmospheric aerosols containing mixtures of electrolytes, organics, and water

    Science.gov (United States)

    Tong, Chinghang; Clegg, Simon L.; Seinfeld, John H.

    Atmospheric aerosols generally comprise a mixture of electrolytes, organic compounds, and water. Determining the gas-particle distribution of volatile compounds, including water, requires equilibrium or mass transfer calculations, at the heart of which are models for the activity coefficients of the particle-phase components. We evaluate here the performance of four recent activity coefficient models developed for electrolyte/organic/water mixtures typical of atmospheric aerosols. Two of the models, the CSB model [Clegg, S.L., Seinfeld, J.H., Brimblecombe, P., 2001. Thermodynamic modelling of aqueous aerosols containing electrolytes and dissolved organic compounds. Journal of Aerosol Science 32, 713-738] and the aerosol diameter dependent equilibrium model (ADDEM) [Topping, D.O., McFiggans, G.B., Coe, H., 2005. A curved multi-component aerosol hygroscopicity model framework: part 2—including organic compounds. Atmospheric Chemistry and Physics 5, 1223-1242] treat ion-water and organic-water interactions but do not include ion-organic interactions; these can be referred to as "decoupled" models. The other two models, reparameterized Ming and Russell model 2005 [Raatikainen, T., Laaksonen, A., 2005. Application of several activity coefficient models to water-organic-electrolyte aerosols of atmospheric interest. Atmospheric Chemistry and Physics 5, 2475-2495] and X-UNIFAC.3 [Erdakos, G.B., Change, E.I., Pandow, J.F., Seinfeld, J.H., 2006. Prediction of activity coefficients in liquid aerosol particles containing organic compounds, dissolved inorganic salts, and water—Part 3: Organic compounds, water, and ionic constituents by consideration of short-, mid-, and long-range effects using X-UNIFAC.3. Atmospheric Environment 40, 6437-6452], include ion-organic interactions; these are referred to as "coupled" models. We address the question—Does the inclusion of a treatment of ion-organic interactions substantially improve the performance of the coupled models over

  9. Inferring modulators of genetic interactions with epistatic nested effects models.

    Science.gov (United States)

    Pirkl, Martin; Diekmann, Madeline; van der Wees, Marlies; Beerenwinkel, Niko; Fröhlich, Holger; Markowetz, Florian

    2017-04-01

    Maps of genetic interactions can dissect functional redundancies in cellular networks. Gene expression profiles as high-dimensional molecular readouts of combinatorial perturbations provide a detailed view of genetic interactions, but can be hard to interpret if different gene sets respond in different ways (called mixed epistasis). Here we test the hypothesis that mixed epistasis between a gene pair can be explained by the action of a third gene that modulates the interaction. We have extended the framework of Nested Effects Models (NEMs), a type of graphical model specifically tailored to analyze high-dimensional gene perturbation data, to incorporate logical functions that describe interactions between regulators on downstream genes and proteins. We benchmark our approach in the controlled setting of a simulation study and show high accuracy in inferring the correct model. In an application to data from deletion mutants of kinases and phosphatases in S. cerevisiae we show that epistatic NEMs can point to modulators of genetic interactions. Our approach is implemented in the R-package 'epiNEM' available from https://github.com/cbg-ethz/epiNEM and https://bioconductor.org/packages/epiNEM/.

  10. Stochastic hyperfine interactions modeling library-Version 2

    Science.gov (United States)

    Zacate, Matthew O.; Evenson, William E.

    2016-02-01

    The stochastic hyperfine interactions modeling library (SHIML) provides a set of routines to assist in the development and application of stochastic models of hyperfine interactions. The library provides routines written in the C programming language that (1) read a text description of a model for fluctuating hyperfine fields, (2) set up the Blume matrix, upon which the evolution operator of the system depends, and (3) find the eigenvalues and eigenvectors of the Blume matrix so that theoretical spectra of experimental techniques that measure hyperfine interactions can be calculated. The optimized vector and matrix operations of the BLAS and LAPACK libraries are utilized. The original version of SHIML constructed and solved Blume matrices for methods that measure hyperfine interactions of nuclear probes in a single spin state. Version 2 provides additional support for methods that measure interactions on two different spin states such as Mössbauer spectroscopy and nuclear resonant scattering of synchrotron radiation. Example codes are provided to illustrate the use of SHIML to (1) generate perturbed angular correlation spectra for the special case of polycrystalline samples when anisotropy terms of higher order than A22 can be neglected and (2) generate Mössbauer spectra for polycrystalline samples for pure dipole or pure quadrupole transitions.

  11. Interactive edgewise mechanisms: form and function comparison with conventional edgewise brackets.

    Science.gov (United States)

    Voudouris, J C

    1997-02-01

    As the frequency of use of the interactive twin (I-twin) edgewise mechanisms and techniques become increasingly prevalent, it is important to consider how they compare with conventional twin (c-twin) edgewise bracket systems. Optimum intrabracket and interbracket forces in I-twins balance with capillary blood pressures. An unbiased, experimental in vitro, scanning electromicroscopy and in vivo clinical investigation of 83 patients was conducted to compare the frictional resistance of three different I-twin bracket systems, type A (Sigma, American Orthodontics), type B (Interactwin, Ormco Corp.), and type C (Damon, A-company) with three c-twins counterparts respectively types D, E, and F. The three interactive twin brackets were each self-seating by an integrated arm component and made significant incremental improvements to the conventional twins in three different ways. First, the I-twin types reduced frictional resistance by using arm engagement with a lower coefficient of friction and a reduced seating force against the arch wire. The reduced seating force friction produced initially small interbracket arch wire deflections for biocompatible tooth movement and, combined with a wide twin bracket, produced accurate rotation corrections. Reduced friction within the I-twin bracket consequently permitted the effective use of light forces for flowing biomechanics that maximized anchorage. In evaluating friction, two distinctly different interaction forces acting to seat the arch wire were also identified. Type A demonstrated active interaction with round arch wires that resulted in a low functional seating force responsible for early and complete tooth control in comparison to the high seating force of c-twins. Types B and C both showed passive interaction with seating force friction approximately equal to zero that required large rectangular dimension arch wires for full bracket expression. Second, a significant reduction in the time taken to change arch wires was

  12. Spoken language interaction with model uncertainty: an adaptive human-robot interaction system

    Science.gov (United States)

    Doshi, Finale; Roy, Nicholas

    2008-12-01

    Spoken language is one of the most intuitive forms of interaction between humans and agents. Unfortunately, agents that interact with people using natural language often experience communication errors and do not correctly understand the user's intentions. Recent systems have successfully used probabilistic models of speech, language and user behaviour to generate robust dialogue performance in the presence of noisy speech recognition and ambiguous language choices, but decisions made using these probabilistic models are still prone to errors owing to the complexity of acquiring and maintaining a complete model of human language and behaviour. In this paper, a decision-theoretic model for human-robot interaction using natural language is described. The algorithm is based on the Partially Observable Markov Decision Process (POMDP), which allows agents to choose actions that are robust not only to uncertainty from noisy or ambiguous speech recognition but also unknown user models. Like most dialogue systems, a POMDP is defined by a large number of parameters that may be difficult to specify a priori from domain knowledge, and learning these parameters from the user may require an unacceptably long training period. An extension to the POMDP model is described that allows the agent to acquire a linguistic model of the user online, including new vocabulary and word choice preferences. The approach not only avoids a training period of constant questioning as the agent learns, but also allows the agent actively to query for additional information when its uncertainty suggests a high risk of mistakes. The approach is demonstrated both in simulation and on a natural language interaction system for a robotic wheelchair application.

  13. Galaxy Zoo: Mergers - Dynamical Models of Interacting Galaxies

    CERN Document Server

    Holincheck, Anthony J; Borne, Kirk; Fortson, Lucy; Lintott, Chris; Smith, Arfon M; Bamford, Steven; Keel, William C; Parrish, Michael

    2016-01-01

    The dynamical history of most merging galaxies is not well understood. Correlations between galaxy interaction and star formation have been found in previous studies, but require the context of the physical history of merging systems for full insight into the processes that lead to enhanced star formation. We present the results of simulations that reconstruct the orbit trajectories and disturbed morphologies of pairs of interacting galaxies. With the use of a restricted three-body simulation code and the help of Citizen Scientists, we sample 10^5 points in parameter space for each system. We demonstrate a successful recreation of the morphologies of 62 pairs of interacting galaxies through the review of more than 3 million simulations. We examine the level of convergence and uniqueness of the dynamical properties of each system. These simulations represent the largest collection of models of interacting galaxies to date, providing a valuable resource for the investigation of mergers. This paper presents the ...

  14. Understanding Peptide Dendrimer Interactions with Model Cell Membrane Mimics

    DEFF Research Database (Denmark)

    Lind, Tania Kjellerup

    membranes or highly conserved motifs, effectively making resistance due to mutations less likely to develop and spread. For this we studied the conditions to form supported lipid bilayers with basic systems and further established a protocol for producing biomimetic bacterial model membranes via the vesicle...... fusion method, which presents improved means for studying drug-membrane interactions in the future. The interaction mechanism of a family of dendrimers was examined and in particular one dendrimer (BALY) was extensively studied by the combined use of quartz crystal microbalance, atomic force microscopy...... and neutron reection. The application of several complementary surface-sensitive techniques allowed for systematically addressing the interface-related processes and gain insights into different aspects of the interaction. BALY was found to interact via a uidity-dependent mechanism. It inserted into the outer...

  15. Model inter-comparison on transport and chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Bergamaschi, P. [European Commission, DG Joint Research Centre, Institute for Environment and Sustainability, Ispra (Italy); Meirink, J.F. [Royal Netherlands Meteorological Institute KNMI, De Bilt (Netherlands); Mueller, J.F. [Belgian Institute for Space Aeronomy, Brussels (Belgium); Koerner, S.; Heimann, M. [Max Planck Institute for Biogeochemie, Jena (Germany); Bousquet, P.; Ramonet, M. [Laboratoire des Sciences du Climat et de l' Environment LSCE, Gif sur Yvette (France); Dlugokencky, E.J. [NOAA Earth Science Research Laboratory, Global Monitoring Division, Boulder, CO (United States); Kaminski, U. [Deutscher Wetterdienst, Meteorologisches Observatorium Hohenpeissenberg (Germany); Vecchi, R.; Marcazzan, G. [Istituto di Fisica Generale Applicata, Universita' degli Studi di Milano, Milan (Italy); Meinhardt, F. [Umweltbundesamt, Messstelle Schauinsland, Kirchzarten (Germany); Sartorius, H. [Bundesamt fuer Strahlenschutz, Freiburg (Germany); Zahorowski, W. [Australian Nuclear Science and Technology Organisation, Menai (Australia)

    2006-07-01

    A comprehensive inter-comparison of 5 atmospheric chemistry transport models (TM5, TM4, TM3, IMAGES, and LMDZ) has been performed. The main objective was to analyze differences in model transport, in particular vertical mixing (boundary layer and convective transport), synoptic variations, and large scale global circulation (including inter-hemispheric exchange and stratospheric tropospheric exchange (STE)). For this purpose simulations of various tracers with very different atmospheric lifetimes {tau} have been carried out: 222Rn ({tau} = 3.8 days), SF6 ({tau} {approx}3000 years), and CH4 ({tau} = {approx}9 years), using prescribed boundary conditions for all models. Furthermore, OH fields from various model simulations with full chemistry have been compared.

  16. Bayesian Model Comparison With the g-Prior

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Christensen, Mads Græsbøll; Cemgil, Ali Taylan

    2014-01-01

    Model comparison and selection is an important problem in many model-based signal processing applications. Often, very simple information criteria such as the Akaike information criterion or the Bayesian information criterion are used despite their shortcomings. Compared to these methods, Djuric......’s asymptotic MAP rule was an improvement, and in this paper we extend the work by Djuric in several ways. Specifically, we consider the elicitation of proper prior distributions, treat the case of real- and complex-valued data simultaneously in a Bayesian framework similar to that considered by Djuric......, and develop new model selection rules for a regression model containing both linear and non-linear parameters. Moreover, we use this framework to give a new interpretation of the popular information criteria and relate their performance to the signal-to-noise ratio of the data. By use of simulations, we also...

  17. ANALYSIS OF THE KQML MODEL IN MULTI-AGENT INTERACTION

    Institute of Scientific and Technical Information of China (English)

    刘海龙; 吴铁军

    2001-01-01

    Our analysis of the KQML(Knowledge Query and Manipulation Language) model yielded some conclusions on the knowledge level of communication in agent-oriented program. First, the agent state and transition model were given for analyzing the necessary conditions for interaction with the synchronal and asynchronous KQML model respectively. Second, we analyzed the deadlock and starvation problems in the KQML communication, and gave the solution. At last, the advantages and disadvantages of the synchronal and asynchronous KQML model were listed respectively, and the choosing principle was given.

  18. iMarNet: an ocean biogeochemistry model inter-comparison project within a common physical ocean modelling framework

    Directory of Open Access Journals (Sweden)

    L. Kwiatkowski

    2014-07-01

    Full Text Available Ocean biogeochemistry (OBGC models span a wide range of complexities from highly simplified, nutrient-restoring schemes, through nutrient-phytoplankton-zooplankton-detritus (NPZD models that crudely represent the marine biota, through to models that represent a broader trophic structure by grouping organisms as plankton functional types (PFT based on their biogeochemical role (Dynamic Green Ocean Models; DGOM and ecosystem models which group organisms by ecological function and trait. OBGC models are now integral components of Earth System Models (ESMs, but they compete for computing resources with higher resolution dynamical setups and with other components such as atmospheric chemistry and terrestrial vegetation schemes. As such, the choice of OBGC in ESMs needs to balance model complexity and realism alongside relative computing cost. Here, we present an inter-comparison of six OBGC models that were candidates for implementation within the next UK Earth System Model (UKESM1. The models cover a large range of biological complexity (from 7 to 57 tracers but all include representations of at least the nitrogen, carbon, alkalinity and oxygen cycles. Each OBGC model was coupled to the Nucleus for the European Modelling of the Ocean (NEMO ocean general circulation model (GCM, and results from physically identical hindcast simulations were compared. Model skill was evaluated for biogeochemical metrics of global-scale bulk properties using conventional statistical techniques. The computing cost of each model was also measured in standardised tests run at two resource levels. No model is shown to consistently outperform or underperform all other models across all metrics. Nonetheless, the simpler models that are easier to tune are broadly closer to observations across a number of fields, and thus offer a high-efficiency option for ESMs that prioritise high resolution climate dynamics. However, simpler models provide limited insight into more complex

  19. Modeling land-surface processes and land-atmosphere interactions in the community weather and regional climate WRF model (Invited)

    Science.gov (United States)

    Chen, F.; Barlage, M. J.

    2013-12-01

    The Weather Research and Forecasting (WRF) model has been widely used with high-resolution configuration in the weather and regional climate communities, and hence demands its land-surface models to treat not only fast-response processes, such as plant evapotranspiration that are important for numerical weather prediction but also slow-evolving processes such as snow hydrology and interactions between surface soil water and deep aquifer. Correctly representing urbanization, which has been traditionally ignored in coarse-resolution modeling, is critical for applying WRF to air quality and public health research. To meet these demands, numerous efforts have been undertaken to improve land-surface models (LSM) in WRF, including the recent implementation of the Noah-MP (Noah Multiple-Physics). Noah-MP uses multiple options for key sub-grid land-atmosphere interaction processes (Niu et al., 2011; Yang et al., 2011), and contains a separate vegetation canopy representing within- and under-canopy radiation and turbulent processes, a multilayer physically-based snow model, and a photosynthesis canopy resistance parameterization with a dynamic vegetation model. This paper will focus on the interactions between fast and slow land processes through: 1) a benchmarking of the Noah-MP performance, in comparison to five widely-used land-surface models, in simulating and diagnosing snow evolution for complex terrain forested regions, and 2) the effects of interactions between shallow and deep aquifers on regional weather and climate. Moreover, we will provide an overview of recent improvements of the integrated WRF-Urban modeling system, especially its hydrological enhancements that takes into account the effects of lawn irrigation, urban oasis, evaporation from pavements, anthropogenic moisture sources, and a green-roof parameterization.

  20. An exotic k-essence interpretation of interactive cosmological models

    Energy Technology Data Exchange (ETDEWEB)

    Forte, Monica [Universidad de Buenos Aires, Departamento de Fisica, Facultad de ciencias Exactas y Naturales, Buenos Aires (Argentina)

    2016-01-15

    We define a generalization of scalar fields with non-canonical kinetic term which we call exotic k-essence or, briefly, exotik. These fields are generated by the global description of cosmological models with two interactive fluids in the dark sector and under certain conditions they correspond to usual k-essences. The formalism is applied to the cases of constant potential and of inverse square potential and also we develop the purely exotik version for the modified holographic Ricci type (MHR) of dark energy, where the equations of state are not constant. With the kinetic function F = 1 + mx and the inverse square potential we recover, through the interaction term, the identification between k-essences and quintessences of an exponential potential, already known for Friedmann-Robertson-Walker and Bianchi type I geometries. Worked examples are shown that include the self-interacting MHR and also models with crossing of the phantom divide line (PDL). (orig.)

  1. Interactions between Octet Baryons in the SU_6 Quark model

    CERN Document Server

    Fujiwara, Y; Nakamoto, C; Suzuki, Y

    2001-01-01

    The baryon-baryon interactions for the complete baryon octet (B_8) are investigated in a unified framework of the resonating-group method, in which the spin-flavor SU_6 quark-model wave functions are employed. Model parameters are determined to reproduce properties of the nucleon-nucleon system and the low-energy cross section data for the hyperon-nucleon interaction. We then proceed to explore B_8 B_8 interactions in the strangeness S=-2, -3 and -4 sectors. The S-wave phase-shift behavior and total cross sections are systematically understood by 1) the spin-flavor SU_6 symmetry, 2) the special role of the pion exchange, and 3) the flavor symmetry breaking.

  2. Enhanced compressibility due to repulsive interaction in the Harper model

    Science.gov (United States)

    Kraus, Yaacov E.; Zilberberg, Oded; Berkovits, Richard

    2014-04-01

    We study the interplay between a repulsive interaction and an almost staggered on-site potential in one dimension. Specifically, we address the Harper model for spinless fermions with nearest-neighbor repulsion, close to half filling. Using the density matrix renormalization group, we find that, in contrast to standard behavior, the system becomes more compressible as the repulsive interaction is increased. By deriving a low-energy effective model, we unveil the effect of interactions using mean-field analysis: The density of a narrow band around half filling is anticorrelated with the on-site potential, whereas the density of lower occupied bands follows the potential and strengthens it. As a result, the states around half filling are squeezed by the background density, their band becomes flatter, and the compressibility increases.

  3. Interaction of quercetin with ovalbumin: Spectroscopic and molecular modeling studies

    Energy Technology Data Exchange (ETDEWEB)

    Lu Yan, E-mail: yanlu2001@sohu.co [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); Wang Yunlai; Gao Shenghua; Wang Gongke; Yan Changling; Chen Dejun [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China)

    2009-09-15

    The binding of quercetin (QCT) to ovalbumin (OVA) in aqueous solution was investigated by molecular spectroscopy and modeling at pH 7.4. The fluorescence, synchronous fluorescence and UV-absorption spectroscopies were employed to study the mode and the mechanism for this interaction. QCT binding is characterized by one high affinity binding site with the association constants of the order of 10{sup 5}. The distance between donor (OVA) and acceptor (QCT) was estimated according to Forster's theory of non-radiation energy transfer. Molecular docking showed that the QCT can bind to the active site of OVA. The binding dynamics was expounded by thermodynamic parameters, molecular modeling and accessible surface area calculation, which entails that hydrophobic interactions, hydrogen bonding and electrostatic forces stabilizes the interaction.

  4. An exotic k-essence interpretation of interactive cosmological models

    CERN Document Server

    Forte, Mónica

    2015-01-01

    We define a generalization of scalar fields with non-canonical kinetic term which we call exotic k-essence or briefly, exotik. These fields are generated by the global description of cosmological models with two interactive fluids in the dark sector and under certain conditions, they correspond to usual k-essences. The formalism is applied to the cases of constant potential and of inverse square potential and also we develop the purely exotik version for the modified holographic Ricci type of dark energy (MHR), where the equations of state are not constant. With the kinetic function $F=1+mx$ and the inverse square potential we recover, through the interaction term, the identification between k-essences and quintessences of exponential potential, already known for Friedmann-Robertson-Walker and Bianchi type I geometries. Worked examples are shown that include the self-interacting MHR and also models with crossing of the phantom divide line (PDL).

  5. Bayesian inference and model comparison for metallic fatigue data

    KAUST Repository

    Babuška, Ivo

    2016-02-23

    In this work, we present a statistical treatment of stress-life (S-N) data drawn from a collection of records of fatigue experiments that were performed on 75S-T6 aluminum alloys. Our main objective is to predict the fatigue life of materials by providing a systematic approach to model calibration, model selection and model ranking with reference to S-N data. To this purpose, we consider fatigue-limit models and random fatigue-limit models that are specially designed to allow the treatment of the run-outs (right-censored data). We first fit the models to the data by maximum likelihood methods and estimate the quantiles of the life distribution of the alloy specimen. To assess the robustness of the estimation of the quantile functions, we obtain bootstrap confidence bands by stratified resampling with respect to the cycle ratio. We then compare and rank the models by classical measures of fit based on information criteria. We also consider a Bayesian approach that provides, under the prior distribution of the model parameters selected by the user, their simulation-based posterior distributions. We implement and apply Bayesian model comparison methods, such as Bayes factor ranking and predictive information criteria based on cross-validation techniques under various a priori scenarios.

  6. Empirical Bayes Model Comparisons for Differential Methylation Analysis

    Directory of Open Access Journals (Sweden)

    Mingxiang Teng

    2012-01-01

    Full Text Available A number of empirical Bayes models (each with different statistical distribution assumptions have now been developed to analyze differential DNA methylation using high-density oligonucleotide tiling arrays. However, it remains unclear which model performs best. For example, for analysis of differentially methylated regions for conservative and functional sequence characteristics (e.g., enrichment of transcription factor-binding sites (TFBSs, the sensitivity of such analyses, using various empirical Bayes models, remains unclear. In this paper, five empirical Bayes models were constructed, based on either a gamma distribution or a log-normal distribution, for the identification of differential methylated loci and their cell division—(1, 3, and 5 and drug-treatment-(cisplatin dependent methylation patterns. While differential methylation patterns generated by log-normal models were enriched with numerous TFBSs, we observed almost no TFBS-enriched sequences using gamma assumption models. Statistical and biological results suggest log-normal, rather than gamma, empirical Bayes model distribution to be a highly accurate and precise method for differential methylation microarray analysis. In addition, we presented one of the log-normal models for differential methylation analysis and tested its reproducibility by simulation study. We believe this research to be the first extensive comparison of statistical modeling for the analysis of differential DNA methylation, an important biological phenomenon that precisely regulates gene transcription.

  7. Centrifugal stretching of 170Hf in the interacting boson model

    Directory of Open Access Journals (Sweden)

    Werner V.

    2014-03-01

    Full Text Available We present the results of a recent experiment to deduce lifetimes of members of the ground state rotational band of 170Hf, which show the effect of centrifugal stretching in this deformed isotope. Results are compared to the geometrical confined beta-soft(CBS rotor model, as well as to the interacting boson model (IBM. Two methods to correct for effects due to the finite valence space within the IBM are proposed.

  8. An Arctic Ice/Ocean Coupled Model with Wave Interactions

    Science.gov (United States)

    2015-09-30

    ocean waves and sea ice interact, for use in operational models of the Arctic Basin and the adjacent seas; – improve the forecasting capacities of...spectra and modify their directional spread. Being the primary focus of the current project, we are developing innovative methods to model these...during WIFAR (Waves-in-Ice Forecasting for Arctic Operators), a partnership between the Nansen Environmental and Remote Sensing Center (NERSC) in

  9. Interactive Visualizations of Complex Seismic Data and Models

    Science.gov (United States)

    Chai, C.; Ammon, C. J.; Maceira, M.; Herrmann, R. B.

    2016-12-01

    The volume and complexity of seismic data and models have increased dramatically thanks to dense seismic station deployments and advances in data modeling and processing. Seismic observations such as receiver functions and surface-wave dispersion are multidimensional: latitude, longitude, time, amplitude and latitude, longitude, period, and velocity. Three-dimensional seismic velocity models are characterized with three spatial dimensions and one additional dimension for the speed. In these circumstances, exploring the data and models and assessing the data fits is a challenge. A few professional packages are available to visualize these complex data and models. However, most of these packages rely on expensive commercial software or require a substantial time investment to master, and even when that effort is complete, communicating the results to others remains a problem. A traditional approach during the model interpretation stage is to examine data fits and model features using a large number of static displays. Publications include a few key slices or cross-sections of these high-dimensional data, but this prevents others from directly exploring the model and corresponding data fits. In this presentation, we share interactive visualization examples of complex seismic data and models that are based on open-source tools and are easy to implement. Model and data are linked in an intuitive and informative web-browser based display that can be used to explore the model and the features in the data that influence various aspects of the model. We encode the model and data into HTML files and present high-dimensional information using two approaches. The first uses a Python package to pack both data and interactive plots in a single file. The second approach uses JavaScript, CSS, and HTML to build a dynamic webpage for seismic data visualization. The tools have proven useful and led to deeper insight into 3D seismic models and the data that were used to construct them

  10. Historical comparisons reveal altered competitive interactions in a guild of crustose coralline algae.

    Science.gov (United States)

    McCoy, S J; Pfister, C A

    2014-04-01

    As the ocean environment changes over time, a paucity of long-term data sets and historical comparisons limits the exploration of community dynamics over time in natural systems. Here, we used a long-term experimental data set to present evidence for a reversal of competitive dominance within a group of crustose coralline algae (CCA) from the 1980s to present time in the northeast Pacific Ocean. CCA are cosmopolitan species distributed globally, and dominant space holders in intertidal and subtidal systems. Competition experiments showed a markedly lower competitive ability of the previous competitively dominant species and a decreased response of competitive dynamics to grazer presence. Competitive networks obtained from survey data showed concordance between the 1980s and 2013, yet also revealed reductions in interaction strengths across the assemblage. We discuss the potential role of environmental change, including ocean acidification, in altered ecological dynamics in this system.

  11. Spreading of correlations in exactly solvable quantum models with long-range interactions in arbitrary dimensions

    Science.gov (United States)

    Cevolani, Lorenzo; Carleo, Giuseppe; Sanchez-Palencia, Laurent

    2016-09-01

    We study the out-of-equilibrium dynamics induced by quantum quenches in quadratic Hamiltonians featuring both short- and long-range interactions. The spreading of correlations in the presence of algebraic decaying interactions, 1/R α , is studied for lattice Bose models in arbitrary dimension D. These models are exactly solvable and provide useful insight in the universal description of more complex systems as well as comparisons to the known universal upper bounds for the spreading of correlations. Using analytical calculations of the dominant terms and full numerical integration of all quasi-particle contributions, we identify three distinct dynamical regimes. For strong decay of interactions, α \\gt D+1, we find a causal regime, qualitatively similar to what previously found for short-range interactions. This regime is characterized by ballistic (linear cone) spreading of the correlations with a cone velocity equal to twice the maximum group velocity of the quasi-particles. For weak decay of interactions, α molecular, and optical systems, and pave the way to the observation of causality and its breaking in diverse experimental realization.

  12. Lattice Boltzmann models with mid-range interactions

    NARCIS (Netherlands)

    Falcucci, Giacomo; Bella, Gino; Shiatti, Giancarlo; Chibbaro, Sergio; Sbragaglia, M.; Succi, Sauro

    2007-01-01

    An extension of the standard Shan-Chen model for non ideal-fluids, catering for mid-range, soft-core and hard-core repulsion, is investigated. It is shown that the inclusion of such mid-range interactions does not yield any visible enhancement of the density jump across the dense and light phases. S

  13. Symmetries of preon interactions modeled as a finite group

    Science.gov (United States)

    Bellinger, James N.

    1997-07-01

    I model preon interactions as a finite group. Treating the elements of the group as the bases of a vector space, I examine those linear mappings under which the transformed bases may be treated as members of a group isomorphic to the original. In some cases these mappings are continuous Lie groups.

  14. Symmetries of preon interactions modeled as a finite group

    Energy Technology Data Exchange (ETDEWEB)

    Bellinger, J.N. [University of Wisconsin at Madison, Madison, Wisconsin 53706 (United States)

    1997-07-01

    I model preon interactions as a finite group. Treating the elements of the group as the bases of a vector space, I examine those linear mappings under which the transformed bases may be treated as members of a group isomorphic to the original. In some cases these mappings are continuous Lie groups. {copyright} {ital 1997 American Institute of Physics.}

  15. Geometric interpretation for the interacting-boson-fermion model

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A.

    1988-08-11

    A geometric oriented approach for studying the interacting-boson-fermion model for odd-A nuclei is presented. A deformed single-particle hamiltonian is derived by means of an algebraic Born-Oppenheimer treatment. Observables concerning spectrum and transitions are calculated for the case of a single-j fermion coupled to a prolate core charge boson number and arbitrary deformations.

  16. ND^(*) and NB^(*) interactions in a chiral quark model

    CERN Document Server

    Yang, Dan; Zhang, Dan

    2015-01-01

    ND and ND^* interactions become a hot topic after the observation of new charmed hadrons \\Sigma_c(2800) and \\Lambda_c(2940)^+. In this letter, we have preliminary investigated S-wave ND and ND^* interactions with possible quantum numbers in the chiral SU(3) quark model and the extended chiral SU(3) quark model by solving the resonating group method equation. The numerical results show that the interactions between N and D or N and D^* are both attractive, which are mainly from \\sigma exchanges between light quarks. Further bound-state studies indicate the attractions are strong enough to form ND or ND^* molecules, except for (ND)_{J=3/2} and (ND^*)_{J=3/2} in the chiral SU(3) quark model. In consequence ND system with J=1/2 and ND^* system with J=3/2 in the extended SU(3) quark model could correspond to the observed \\Sigma_c(2800) and \\Lambda_c(2940)^+, respectively. Naturally, the same method can be applied to research NB and NB^* interactions, and similar conclusions obtained, i.e. NB and NB^* attractive fo...

  17. Modeling Strategic Interactions to Car and Fuel Taxation

    NARCIS (Netherlands)

    Heijnen, P.; Kooreman, P.

    2006-01-01

    We develop a model to analyse the interactions between actors involved in car and fuel taxation: consumers, car producers, fuel producers and the government. Heterogeneous consumers choose between two versions of a car that differ in engine type (diesel or gasoline). Car manufacturers and fuel produ

  18. Kinetic models in spin chemistry. 1. The hyperfine interaction

    DEFF Research Database (Denmark)

    Mojaza, M.; Pedersen, J. B.

    2012-01-01

    Kinetic models for quantum systems are quite popular due to their simplicity, although they are difficult to justify. We show that the transformation from quantum to kinetic description can be done exactly for the hyperfine interaction of one nuclei with arbitrary spin; more spins are described w...

  19. Modeling the interaction of DNA with alternating fields

    CERN Document Server

    Bergues-Pupo, Ana Elisa; Falo, Fernando; 10.1103/PhysRevE.87.022703

    2013-01-01

    We study the influence of a THz field on thermal properties of DNA molecules. A Peyrard- Bishop-Dauxois model with the inclusion of a solvent interaction term is considered. The THz field is included as a sinusoidal driven force in the equation of mo tion. We show how under certain field and system parameters, melting transition and bubble formation are modified.

  20. Interactive Training Model: Enhancing Beginning Counseling Student Development

    Science.gov (United States)

    Paladino, Derrick A.; Minton, Casey A. Barrio; Kern, Carolyn W.

    2011-01-01

    The authors propose the Interactive Training Model (ITM), a full classroom role play experience, as a method for helping student counselors develop essential interviewing and counseling skills and self-awareness as required by the 2009 Council for Accreditation of Counseling and Related Educational Programs "Standards." This pre-post,…

  1. Architectural models for client interaction on service-oriented platforms

    NARCIS (Netherlands)

    Bonino da Silva Santos, L.O.; Ferreira Pires, L.; Sinderen, van M.J.; Sinderen, van M.J.

    2007-01-01

    Service-oriented platforms can provide different levels of functionality to the client applications as well as different interaction models. Depending on the platform’s goals and the computing capacity of their expected clients the platform functionality can range from just an interface to support t

  2. Quantization of a billiard model for interacting particles

    CERN Document Server

    Papenbrock, T; Papenbrock, Thomas; Prosen, Tomaz

    2000-01-01

    We consider a billiard model of a self-bound, interacting three-body system in two spatial dimensions. Numerical studies show that the classical dynamics is chaotic. The corresponding quantum system displays spectral fluctuations that exhibit small deviations from random matrix theory predictions. These can be understood in terms of scarring caused by a 1-parameter family of orbits inside the collinear manifold.

  3. SU(5) symmetry of spdfg interacting boson model

    Institute of Scientific and Technical Information of China (English)

    LI; Jingsheng(李京生); LIU; Yuxin(刘玉鑫); GAO; Peng(高鹏)

    2003-01-01

    The extended interacting boson model with s-, p-, d-, f- and g-bosons included (spdfg IBM)is investigated. The algebraic structure including the generators, the Casimir operators of the groups at the SU(5) dynamical symmetry and the branching rules of the irreducible representation reductions along the group chain are obtained. The typical energy spectrum of the symmetry is given.

  4. Observations and models for needle-tissue interactions

    NARCIS (Netherlands)

    Misra, Sarthak; Reed, Kyle B.; Schafer, Benjamin W.; Ramesh, K.T.; Okamura, Allison M.

    2009-01-01

    The asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. In this study we present a mechanics-based model that calculates the deflection of the needle embedded in an elastic medium. Microscopic observations for several needle- gel interactions

  5. A Viscous-Inviscid Interaction Model for Rotor Aerodynamics

    DEFF Research Database (Denmark)

    Filippone, Antonino; Sørensen, Jens Nørkær

    1994-01-01

    A numerical model for the viscous-inviscid interactive computations ofrotor flows is presented. The basic methodology for deriving the outer inviscid solution is a fully three-dimensional boundary element method.The inner viscous domain, i.e. the boundary layer, is described by the two-dimensiona...

  6. Modeling Strategic Interactions to Car and Fuel Taxation

    NARCIS (Netherlands)

    Heijnen, P.; Kooreman, P.

    2006-01-01

    We develop a model to analyse the interactions between actors involved in car and fuel taxation: consumers, car producers, fuel producers and the government. Heterogeneous consumers choose between two versions of a car that differ in engine type (diesel or gasoline). Car manufacturers and fuel

  7. Comparison between analytical and numerical solution of mathematical drying model

    Science.gov (United States)

    Shahari, N.; Rasmani, K.; Jamil, N.

    2016-02-01

    Drying is often related to the food industry as a process of shifting heat and mass inside food, which helps in preserving food. Previous research using a mass transfer equation showed that the results were mostly concerned with the comparison between the simulation model and the experimental data. In this paper, the finite difference method was used to solve a mass equation during drying using different kinds of boundary condition, which are equilibrium and convective boundary conditions. The results of these two models provide a comparison between the analytical and the numerical solution. The result shows a close match between the two solution curves. It is concluded that the two proposed models produce an accurate solution to describe the moisture distribution content during the drying process. This analysis indicates that we have confidence in the behaviour of moisture in the numerical simulation. This result demonstrated that a combined analytical and numerical approach prove that the system is behaving physically. Based on this assumption, the model of mass transfer was extended to include the temperature transfer, and the result shows a similar trend to those presented in the simpler case.

  8. Lindley-Shannon Information for Comparison of Priors Under Paired Comparisons Model

    Directory of Open Access Journals (Sweden)

    Muhammad Aslam

    2015-09-01

    Full Text Available One of the main differences between classical statistics and Bayesian statistics is that the latter can utilise prior information in a formal way. This information can be quantified in terms of a probability distribution which is known as the prior distribution. If there is no relevant prior information available then there are ways to derive a 'non-informative' prior distribution. In this study, the informative and non-informative prior distributions for the parameters of the Bradley-Terry model for paired comparison data are compared.

  9. Numerical Comparison of Solutions of Kinetic Model Equations

    Directory of Open Access Journals (Sweden)

    A. A. Frolova

    2015-01-01

    Full Text Available The collision integral approximation by different model equations has created a whole new trend in the theory of rarefied gas. One widely used model is the Shakhov model (S-model obtained by expansion of inverse collisions integral in a series of Hermite polynomials up to the third order. Using the same expansion with another value of free parameters leads to a linearized ellipsoidal statistical model (ESL.Both model equations (S and ESL have the same properties, as they give the correct relaxation of non-equilibrium stress tensor components and heat flux vector, the correct Prandtl number at the transition to the hydrodynamic regime and do not guarantee the positivity of the distribution function.The article presents numerical comparison of solutions of Shakhov equation, ESL- model and full Boltzmann equation in the four Riemann problems for molecules of hard spheres.We have considered the expansion of two gas flows, contact discontinuity, the problem of the gas counter-flows and the problem of the shock wave structure. For the numerical solution of the kinetic equations the method of discrete ordinates is used.The comparison shows that solution has a weak sensitivity to the form of collision operator in the problem of expansions of two gas flows and results obtained by the model and the kinetic Boltzmann equations coincide.In the problem of the contact discontinuity the solution of model equations differs from full kinetic solutions at the point of the initial discontinuity. The non-equilibrium stress tensor has the maximum errors, the error of the heat flux is much smaller, and the ESL - model gives the exact value of the extremum of heat flux.In the problems of gas counter-flows and shock wave structure the model equations give significant distortion profiles of heat flux and non-equilibrium stress tensor components in front of the shock waves. This behavior is due to fact that in the models under consideration there is no dependency of the

  10. Mathematical model for hit phenomena as stochastic process of interactions of human interactions

    CERN Document Server

    Ishii, Akira; Matsuda, Naoya; Umemura, Sanae; Urushidani, Tamiko; Yamagata, Naoya; Yoshda, Narihiko

    2011-01-01

    Mathematical model for hit phenomena in entertainments in the society is presented as stochastic process of interactions of human dynamics. The model use only the time distribution of advertisement budget as input and the words of mouth (WOM) as posting in the social network system is used as the data to compare with the calculated results. The unit of time is daily. The WOM distribution in time is found to be very close to the residue distribution in time. The calculations for Japanese motion picture market due to the mathematical model agree very well with the actual residue distribution in time.

  11. A coarse grain model for protein-surface interactions

    Science.gov (United States)

    Wei, Shuai; Knotts, Thomas A.

    2013-09-01

    The interaction of proteins with surfaces is important in numerous applications in many fields—such as biotechnology, proteomics, sensors, and medicine—but fundamental understanding of how protein stability and structure are affected by surfaces remains incomplete. Over the last several years, molecular simulation using coarse grain models has yielded significant insights, but the formalisms used to represent the surface interactions have been rudimentary. We present a new model for protein surface interactions that incorporates the chemical specificity of both the surface and the residues comprising the protein in the context of a one-bead-per-residue, coarse grain approach that maintains computational efficiency. The model is parameterized against experimental adsorption energies for multiple model peptides on different types of surfaces. The validity of the model is established by its ability to quantitatively and qualitatively predict the free energy of adsorption and structural changes for multiple biologically-relevant proteins on different surfaces. The validation, done with proteins not used in parameterization, shows that the model produces remarkable agreement between simulation and experiment.

  12. Modeling attacker-defender interactions in information networks.

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Michael Joseph

    2010-09-01

    The simplest conceptual model of cybersecurity implicitly views attackers and defenders as acting in isolation from one another: an attacker seeks to penetrate or disrupt a system that has been protected to a given level, while a defender attempts to thwart particular attacks. Such a model also views all non-malicious parties as having the same goal of preventing all attacks. But in fact, attackers and defenders are interacting parts of the same system, and different defenders have their own individual interests: defenders may be willing to accept some risk of successful attack if the cost of defense is too high. We have used game theory to develop models of how non-cooperative but non-malicious players in a network interact when there is a substantial cost associated with effective defensive measures. Although game theory has been applied in this area before, we have introduced some novel aspects of player behavior in our work, including: (1) A model of how players attempt to avoid the costs of defense and force others to assume these costs; (2) A model of how players interact when the cost of defending one node can be shared by other nodes; and (3) A model of the incentives for a defender to choose less expensive, but less effective, defensive actions.

  13. Plant-herbivore interactions along elevational gradient: Comparison of field and common garden data

    Science.gov (United States)

    Rokaya, Maan Bahadur; Dostálek, Tomáš; Münzbergová, Zuzana

    2016-11-01

    In response to climate change, various organisms tend to migrate to higher elevations and latitudes. Unequal migration rates of plants and animals are expected to result in changes in the type and intensity of their interactions such as plant-herbivore interactions. In the present study, we studied the extent of herbivore damage in Salvia nubicola along an elevational gradient in Manang, central Nepal. A common garden experiment was also carried out by sowing seeds collected from different populations along the elevational gradient. As expected, the extent of herbivore damage in the field was significantly lower at higher elevations, and it increased with the population size and at sites without shrubs. In the common garden experiment, herbivore damage was higher in plants originating from lower elevations and from more open habitats. While higher herbivore pressure in the field at lower elevations may suggest that plants will be better protected against herbivores at lower elevations, the common garden study demonstrated the opposite. A possible explanation could be that plants from higher elevations have to adapt to extreme conditions, and lower palatability is a side effect of these adaptations. Thus, S. nubicola in the Himalayan region is likely to survive the expected higher herbivore pressure caused by an upward shift of herbivores under future climate change. Future studies should attempt to elucidate generality of such a conclusion by studying multiple species along similar gradients. Our results from comparison of the field and common garden study suggest that future experiments need to include comparisons in common environments to understand the expected response of plants to changes in herbivore pressure.

  14. Ultrasound Evaluation of an Abdominal Aortic Fluid-Structure Interaction Model

    DEFF Research Database (Denmark)

    Traberg, Marie Sand; Jensen, Jørgen Arendt

    2014-01-01

    Ultrasound measurements are used for evaluating biomechanics of the abdominal aorta (AA) predicted by a fluid- structure interaction (FSI) simulation model. FSI simulation models describe the complete arterial physiology by quantify- ing the mechanical response in the vessel wall caused by the pe......Ultrasound measurements are used for evaluating biomechanics of the abdominal aorta (AA) predicted by a fluid- structure interaction (FSI) simulation model. FSI simulation models describe the complete arterial physiology by quantify- ing the mechanical response in the vessel wall caused...... by the percolating pulsating blood. But the predictability of FSI models needs validation for these to be usable for diagnostic purposes. Ultrasound measurements are suitable for such an evaluation as the wall displacement can be measured in vivo and compared to the wall displacement simulated in the FSI model....... Spectral Doppler velocity data from 3 healthy male volunteers were used to construct inlet profiles for the FSI model. Simultaneously, wall movement was tracked and used for comparison to FSI model results. Ultrasound data were acquired using a scanner equipped with a research interface. The wall...

  15. Baryons and baryonic matter in four-fermion interaction models

    Energy Technology Data Exchange (ETDEWEB)

    Urlichs, K.

    2007-02-23

    In this work we discuss baryons and baryonic matter in simple four-fermion interaction theories, the Gross-Neveu model and the Nambu-Jona-Lasinio model in 1+1 and 2+1 space-time dimensions. These models are designed as toy models for dynamical symmetry breaking in strong interaction physics. Pointlike interactions (''four-fermion'' interactions) between quarks replace the full gluon mediated interaction of quantum chromodynamics. We consider the limit of a large number of fermion flavors, where a mean field approach becomes exact. This method is formulated in the language of relativistic many particle theory and is equivalent to the Hartree-Fock approximation. In 1+1 dimensions, we generalize known results on the ground state to the case where chiral symmetry is broken explicitly by a bare mass term. For the Gross-Neveu model, we derive an exact self-consistent solution for the finite density ground state, consisting of a one-dimensional array of equally spaced potential wells, a baryon crystal. For the Nambu- Jona-Lasinio model we apply the derivative expansion technique to calculate the total energy in powers of derivatives of the mean field. In a picture akin to the Skyrme model of nuclear physics, the baryon emerges as a topological soliton. The solution for both the single baryon and dense baryonic matter is given in a systematic expansion in powers of the pion mass. The solution of the Hartree-Fock problem is more complicated in 2+1 dimensions. In the massless Gross-Neveu model we derive an exact self-consistent solution by extending the baryon crystal of the 1+1 dimensional model, maintaining translational invariance in one spatial direction. This one-dimensional configuration is energetically degenerate to the translationally invariant solution, a hint in favor of a possible translational symmetry breakdown by more general geometrical structures. In the Nambu-Jona-Lasinio model, topological soliton configurations induce a finite baryon

  16. Systems pharmacology - Towards the modeling of network interactions.

    Science.gov (United States)

    Danhof, Meindert

    2016-10-30

    Mechanism-based pharmacokinetic and pharmacodynamics (PKPD) and disease system (DS) models have been introduced in drug discovery and development research, to predict in a quantitative manner the effect of drug treatment in vivo in health and disease. This requires consideration of several fundamental properties of biological systems behavior including: hysteresis, non-linearity, variability, interdependency, convergence, resilience, and multi-stationarity. Classical physiology-based PKPD models consider linear transduction pathways, connecting processes on the causal path between drug administration and effect, as the basis of drug action. Depending on the drug and its biological target, such models may contain expressions to characterize i) the disposition and the target site distribution kinetics of the drug under investigation, ii) the kinetics of target binding and activation and iii) the kinetics of transduction. When connected to physiology-based DS models, PKPD models can characterize the effect on disease progression in a mechanistic manner. These models have been found useful to characterize hysteresis and non-linearity, yet they fail to explain the effects of the other fundamental properties of biological systems behavior. Recently systems pharmacology has been introduced as novel approach to predict in vivo drug effects, in which biological networks rather than single transduction pathways are considered as the basis of drug action and disease progression. These models contain expressions to characterize the functional interactions within a biological network. Such interactions are relevant when drugs act at multiple targets in the network or when homeostatic feedback mechanisms are operative. As a result systems pharmacology models are particularly useful to describe complex patterns of drug action (i.e. synergy, oscillatory behavior) and disease progression (i.e. episodic disorders). In this contribution it is shown how physiology-based PKPD and

  17. Comparison of the interaction between three anthocyanins and human serum albumins by spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Lin, E-mail: tanglin@sdnu.edu.cn; Zuo, Huijun; Shu, Li

    2014-09-15

    Anthocyanin is an important kind of water-soluble pigment existing widely in plants, and has various health benefits to human body. The number and location of the hydroxyl groups of the parent nucleus of Anthocyanins have significant effects on their activities. This research employed different spectroscopic methods (i.e. fluorescence spectroscopy, UV–vis absorbance, three-dimensional fluorescence spectra and circular dichroism (CD)) to investigate the mutual interactions between three differently substituted B-ring hydroxyl groups (Pelargonidin-3-O-glucoside, P3G; Cyanidin-3-O-glucoside, C3G and Delphinidin-3-O-glucoside, D3G) and human serum albumin (HSA) under physiological pH conditions. The calculated thermodynamic parameters and the spectrum showed that P3G, C3G and D3G could result in quenching of the intrinsic fluorescence. The comparison result of the strength of comprehensive binding parameter Y (i.e. Y=lg( K{sub a}×E×n/r)), which was used to reflect the extent of interaction of Anthocyanin–HSA system, was Y{sub D3G}>Y{sub C3G}>Y{sub P3G}. Moreover, the secondary structure of HSA was changed in the presence of P3G/C3G/D3G. The α-helix percentage of P3G–HSA increased while that of C3G/D3G–HSA decreased. Overall, these results showed that the number of B-ring –OH in each molecule played an important role in the interaction of these anthocyanins with HSA. - Highlights: • Study the interactions between three differently structured anthocyanins and HSA. • The order of binding parameter Y [Y=lg(K{sub a}×E×n/r)] as Delphinidin>Cyanidin>Pelargonidin. • Increase in the number of B-ring –OH may enhance the binding affinity for HSA. • HSA secondary structural changes occurred due to these interactions. • The number of B-ring –OH in each molecule played an important role in the interaction.

  18. Refreezing on the Greenland ice sheet: a model comparison

    Science.gov (United States)

    Steger, Christian; Reijmer, Carleen; van den Broeke, Michiel; Ligtenberg, Stefan; Kuipers Munneke, Peter; Noël, Brice

    2016-04-01

    Mass loss of the Greenland ice sheet (GrIS) is an important contributor to global sea level rise. Besides calving, surface melt is the dominant source of mass loss. However, only part of the surface melt leaves the ice sheet as runoff whereas the other part percolates into the snow cover and refreezes. Due to this process, part of the meltwater is (intermediately) stored. Refreezing thus impacts the surface mass balance of the ice sheet but it also affects the vertical structure of the snow cover due to transport of mass and energy. Due to the sparse availability of in situ data and the demand of future projections, it is inevitable to use numerical models to simulate refreezing and related processes. Currently, the magnitude of refrozen mass is neither well constrained nor well validated. In this study, we model the snow and firn layer, and compare refreezing on the GrIS as modelled with two different numerical models. Both models are forced with meteorological data from the regional climate model RACMO 2 that has been shown to simulate realistic conditions for Greenland. One model is the UU/IMAU firn densification model (FDM) that can be used both in an on- and offline mode with RACMO 2. The other model is SNOWPACK; a model originally designed to simulate seasonal snow cover in alpine conditions. In contrast to FDM, SNOWPACK accounts for snow metamorphism and microstructure and contains a more physically based snow densification scheme. A first comparison of the models indicates that both seem to be able to capture the general spatial and temporal pattern of refreezing. Spatially, refreezing occurs mostly in the ablation zone and decreases in the accumulation zone towards the interior of the ice sheet. Below the equilibrium line altitude (ELA) where refreezing occurs in seasonal snow cover on bare ice, the storage effect is only intermediate. Temporal patterns on a seasonal range indicate two peaks in refreezing; one at the beginning of the melt season where

  19. Factor selection and structural identification in the interaction ANOVA model.

    Science.gov (United States)

    Post, Justin B; Bondell, Howard D

    2013-03-01

    When faced with categorical predictors and a continuous response, the objective of an analysis often consists of two tasks: finding which factors are important and determining which levels of the factors differ significantly from one another. Often times, these tasks are done separately using Analysis of Variance (ANOVA) followed by a post hoc hypothesis testing procedure such as Tukey's Honestly Significant Difference test. When interactions between factors are included in the model the collapsing of levels of a factor becomes a more difficult problem. When testing for differences between two levels of a factor, claiming no difference would refer not only to equality of main effects, but also to equality of each interaction involving those levels. This structure between the main effects and interactions in a model is similar to the idea of heredity used in regression models. This article introduces a new method for accomplishing both of the common analysis tasks simultaneously in an interaction model while also adhering to the heredity-type constraint on the model. An appropriate penalization is constructed that encourages levels of factors to collapse and entire factors to be set to zero. It is shown that the procedure has the oracle property implying that asymptotically it performs as well as if the exact structure were known beforehand. We also discuss the application to estimating interactions in the unreplicated case. Simulation studies show the procedure outperforms post hoc hypothesis testing procedures as well as similar methods that do not include a structural constraint. The method is also illustrated using a real data example.

  20. Analytical model of interaction of tide and river flow

    Directory of Open Access Journals (Sweden)

    Phairot Chatanantavet

    2006-11-01

    Full Text Available Hydrodynamic characteristics of a river resulting from interaction of tide and river flow are important since problems regarding flood, salinity intrusion, water quality and sedimentation are ubiquitous. The lower reach of the river strongly influenced by tides from the sea, when interacting with river flows, results in a complicated pattern which is simplified to its interaction with four main constituents of tides obtained from harmonic analysis. An analytical model is developed in this study for simulating the hydrodynamic processes in estuarine waters, with the emphasis being given to the interaction between tides and river flows. The perturbation method is used to derive the analytical solution, in which the estuarine flow is separated into steady and unsteady components. Thus the analytical solutions derived consist of two distinct parts; one represents the influence of river flows and the other represents the influence of tides. The application of the model to a case study, the Chao Phraya river, which requires a time series of discharges and loadings at the river mouth to model water quality in the Gulf of Thailand, shows that the model can beautifully and completely simulate the hydrodynamic features of tide and river flow interaction especially in the rainy season when the river discharge is high. Data of tidal discharges are scarce because of high cost of measurement especially in the lower reach of the river strongly influenced by tides from the sea. From this study of relation between tidal discharges and tides, the analytical model can compute tidal discharges from tides correctly. The results of tides and tidal flow can subsequently be used to calculate eddy viscosity and dispersion coefficient for describing salinity and water quality profiles.