WorldWideScience

Sample records for explicit modeling tool

  1. CPsuperH: a Computational Tool for Higgs Phenomenology in the Minimal Supersymmetric Standard Model with Explicit CP Violation

    CERN Document Server

    Lee Jae Sik; Carena, M S; Choi, S Y; Drees, Manuel; Ellis, Jonathan Richard; Wagner, C E M

    2004-01-01

    We provide a detailed description of the Fortran code CPsuperH, a newly--developed computational package that calculates the mass spectrum and decay widths of the neutral and charged Higgs bosons in the Minimal Supersymmetric Standard Model with explicit CP violation. The program is based on recent renormalization-group-improved diagrammatic calculations that include dominant higher--order logarithmic and threshold corrections, b-quark Yukawa-coupling resummation effects and Higgs-boson pole-mass shifts. The code CPsuperH is self--contained (with all subroutines included), is easy and fast to run, and is organized to allow further theoretical developments to be easily implemented. The fact that the masses and couplings of the charged and neutral Higgs bosons are computed at a similar high-precision level makes it an attractive tool for Tevatron, LHC and LC studies, also in the CP-conserving case.

  2. Philosophical Reflections made explicit as a Tool for Mathematical Reasoning

    DEFF Research Database (Denmark)

    Frølund, Sune; Andresen, Mette

    2009-01-01

        A new construct, ‘multidiciplinarity', is prescribed in the curricula of Danish Upper Secondary Schools by governmental regulations since 2006. Multidisciplinarity offers a good chance to introduce philosophical tools or methods in mathematics with the aim to improve the students' learning...... of both subjects, and to study the students' reactions and signs of progressive mathematizing. Based on realistic mathematics education (RME) which is rooted in Hans Freudenthal's idea of mathematics as a human activity, we decided to centre our work on the concept of reflection and to build a model...... for making students reflections in the mathematics class explicit to themselves. In our paper, we present a combination of two stratifications of reflections which were developed recently in works by other authors. The paper outlines our model and exemplifies its use on the teaching of mathematical models...

  3. Modeling Implicit and Explicit Memory.

    NARCIS (Netherlands)

    Raaijmakers, J.G.W.; Ohta, N.; Izawa, C.

    2005-01-01

    Mathematical models of memory are useful for describing basic processes of memory in a way that enables generalization across a number of experimental paradigms. Models that have these characteristics do not just engage in empirical curve-fitting, but may also provide explanations for puzzling

  4. Uncertainty in spatially explicit animal dispersal models

    Science.gov (United States)

    Mooij, Wolf M.; DeAngelis, Donald L.

    2003-01-01

    Uncertainty in estimates of survival of dispersing animals is a vexing difficulty in conservation biology. The current notion is that this uncertainty decreases the usefulness of spatially explicit population models in particular. We examined this problem by comparing dispersal models of three levels of complexity: (1) an event-based binomial model that considers only the occurrence of mortality or arrival, (2) a temporally explicit exponential model that employs mortality and arrival rates, and (3) a spatially explicit grid-walk model that simulates the movement of animals through an artificial landscape. Each model was fitted to the same set of field data. A first objective of the paper is to illustrate how the maximum-likelihood method can be used in all three cases to estimate the means and confidence limits for the relevant model parameters, given a particular set of data on dispersal survival. Using this framework we show that the structure of the uncertainty for all three models is strikingly similar. In fact, the results of our unified approach imply that spatially explicit dispersal models, which take advantage of information on landscape details, suffer less from uncertainly than do simpler models. Moreover, we show that the proposed strategy of model development safeguards one from error propagation in these more complex models. Finally, our approach shows that all models related to animal dispersal, ranging from simple to complex, can be related in a hierarchical fashion, so that the various approaches to modeling such dispersal can be viewed from a unified perspective.

  5. Spatially explicit modeling of greater sage-grouse (Centrocercus urophasianus) habitat in Nevada and northeastern California: a decision-support tool for management

    Science.gov (United States)

    Coates, Peter S.; Casazza, Michael L.; Brussee, Brianne E.; Ricca, Mark A.; Gustafson, K. Benjamin; Overton, Cory T.; Sanchez-Chopitea, Erika; Kroger, Travis; Mauch, Kimberly; Niell, Lara; Howe, Kristy; Gardner, Scott; Espinosa, Shawn; Delehanty, David J.

    2014-01-01

    Greater sage-grouse (Centrocercus urophasianus, hereafter referred to as “sage-grouse”) populations are declining throughout the sagebrush (Artemisia spp.) ecosystem, including millions of acres of potential habitat across the West. Habitat maps derived from empirical data are needed given impending listing decisions that will affect both sage-grouse population dynamics and human land-use restrictions. This report presents the process for developing spatially explicit maps describing relative habitat suitability for sage-grouse in Nevada and northeastern California. Maps depicting habitat suitability indices (HSI) values were generated based on model-averaged resource selection functions informed by more than 31,000 independent telemetry locations from more than 1,500 radio-marked sage-grouse across 12 project areas in Nevada and northeastern California collected during a 15-year period (1998–2013). Modeled habitat covariates included land cover composition, water resources, habitat configuration, elevation, and topography, each at multiple spatial scales that were relevant to empirically observed sage-grouse movement patterns. We then present an example of how the HSI can be delineated into categories. Specifically, we demonstrate that the deviation from the mean can be used to classify habitat suitability into three categories of habitat quality (high, moderate, and low) and one non-habitat category. The classification resulted in an agreement of 93–97 percent for habitat versus non-habitat across a suite of independent validation datasets. Lastly, we provide an example of how space use models can be integrated with habitat models to help inform conservation planning. In this example, we combined probabilistic breeding density with a non-linear probability of occurrence relative to distance to nearest lek (traditional breeding ground) using count data to calculate a composite space use index (SUI). The SUI was then classified into two categories of use

  6. Spatially explicit non-Mendelian diploid model

    OpenAIRE

    Lanchier, N.; Neuhauser, C.

    2009-01-01

    We introduce a spatially explicit model for the competition between type $a$ and type $b$ alleles. Each vertex of the $d$-dimensional integer lattice is occupied by a diploid individual, which is in one of three possible states or genotypes: $aa$, $ab$ or $bb$. We are interested in the long-term behavior of the gene frequencies when Mendel's law of segregation does not hold. This results in a voter type model depending on four parameters; each of these parameters measures the strength of comp...

  7. Usefulness of spatially explicit population models in land management

    Energy Technology Data Exchange (ETDEWEB)

    Turner, M.G. [Oak Ridge National Lab., TN (United States); Arthaud, G.J. [Univ. of Georgia, Athens, GA (United States); Engstrom, R.T. [Tall Timbers Research, Inc., Tallahassee, FL (United States); Hejl, S.J. [US Forest Service, Missoula, MT (United States); Liu, Jianguo [Harvard Institute for International Development, Cambridge, MA (United States); Loeb, S. [Clemson Univ., SC (United States); McKelvey, K. [US Forest Service, Arcata, CA (United States)

    1995-02-01

    Land managers need new tools, such as spatial models, to aid them in their decision-making processes because managing for biodiversity, water quality, or natural disturbance is challenging, and landscapes are complex and dynamic. Spatially explicit population models are helpful to managers because these models consider both species - habitat relationships and the arrangement of habitats in space and time. The visualizations that typically accompany spatially explicit models also permit managers to {open_quotes}see{close_quotes} the effects of alternative management strategies on populations of interest. However, the expense entailed in developing the data bases required for spatially explicit models may limit widespread implementation. In addition, many of the models are developed for one or a few species, and dealing with multiple species in a landscape remains a significant challenge. To be most useful to land managers, spatially explicit population models should be user friendly, easily portable, operate on spatial and temporal scales appropriate to management decisions, and use input and output variables that can be measured affordably. 20 refs.

  8. Spatially explicit modelling of cholera epidemics

    Science.gov (United States)

    Finger, F.; Bertuzzo, E.; Mari, L.; Knox, A. C.; Gatto, M.; Rinaldo, A.

    2013-12-01

    Epidemiological models can provide crucial understanding about the dynamics of infectious diseases. Possible applications range from real-time forecasting and allocation of health care resources to testing alternative intervention mechanisms such as vaccines, antibiotics or the improvement of sanitary conditions. We apply a spatially explicit model to the cholera epidemic that struck Haiti in October 2010 and is still ongoing. The dynamics of susceptibles as well as symptomatic and asymptomatic infectives are modelled at the scale of local human communities. Dissemination of Vibrio cholerae through hydrological transport and human mobility along the road network is explicitly taken into account, as well as the effect of rainfall as a driver of increasing disease incidence. The model is calibrated using a dataset of reported cholera cases. We further model the long term impact of several types of interventions on the disease dynamics by varying parameters appropriately. Key epidemiological mechanisms and parameters which affect the efficiency of treatments such as antibiotics are identified. Our results lead to conclusions about the influence of different intervention strategies on the overall epidemiological dynamics.

  9. Spatially explicit dynamic N-mixture models

    Science.gov (United States)

    Zhao, Qing; Royle, Andy; Boomer, G. Scott

    2017-01-01

    Knowledge of demographic parameters such as survival, reproduction, emigration, and immigration is essential to understand metapopulation dynamics. Traditionally the estimation of these demographic parameters requires intensive data from marked animals. The development of dynamic N-mixture models makes it possible to estimate demographic parameters from count data of unmarked animals, but the original dynamic N-mixture model does not distinguish emigration and immigration from survival and reproduction, limiting its ability to explain important metapopulation processes such as movement among local populations. In this study we developed a spatially explicit dynamic N-mixture model that estimates survival, reproduction, emigration, local population size, and detection probability from count data under the assumption that movement only occurs among adjacent habitat patches. Simulation studies showed that the inference of our model depends on detection probability, local population size, and the implementation of robust sampling design. Our model provides reliable estimates of survival, reproduction, and emigration when detection probability is high, regardless of local population size or the type of sampling design. When detection probability is low, however, our model only provides reliable estimates of survival, reproduction, and emigration when local population size is moderate to high and robust sampling design is used. A sensitivity analysis showed that our model is robust against the violation of the assumption that movement only occurs among adjacent habitat patches, suggesting wide applications of this model. Our model can be used to improve our understanding of metapopulation dynamics based on count data that are relatively easy to collect in many systems.

  10. [Explicit model for searching behavior of predator].

    Science.gov (United States)

    Tiutiunov, Iu V; Sapukhina, N Iu; Senina, I N; Arditi, R

    2002-01-01

    The authors present an approach for explicit modeling of spatio-temporal dynamics of predator-prey community. This approach is based on a reaction-diffusion-adjection PD (prey dependent) system. Local kinetics of population is determined by logistic reproduction function of prey, constant natural mortality of predator and Holling type 2 trophic function. Searching behavior of predator is described by the advective term in predator balance equation assuming the predator acceleration to be proportional to the prey density gradient. The model was studied with zero-flux boundary conditions. The influence of predator searching activity on the community dynamics, in particular, on the emergence of spatial heterogeneity, has been investigated by linear analysis and numerical simulations. It has been shown how searching activity may effect the persistence of species, stabilizing predator-prey interactions at very low level of pest density. It has been demonstrated that obtaining of such dynamic regimes does not require the use of complex trophic functions.

  11. A comparative study of explicit and implicit modelling of ...

    Indian Academy of Sciences (India)

    Further, for both speaker identification and verification tasks the explicit modelling provides relatively more complimentary information to the state-of-the-art vocal tract features. The contribution of the explicit features is relatively more robust against noise. We suggest that the explicit approach can be used to model the ...

  12. Spatially explicit modeling in ecology: A review

    Science.gov (United States)

    DeAngelis, Donald L.; Yurek, Simeon

    2017-01-01

    The use of spatially explicit models (SEMs) in ecology has grown enormously in the past two decades. One major advancement has been that fine-scale details of landscapes, and of spatially dependent biological processes, such as dispersal and invasion, can now be simulated with great precision, due to improvements in computer technology. Many areas of modeling have shifted toward a focus on capturing these fine-scale details, to improve mechanistic understanding of ecosystems. However, spatially implicit models (SIMs) have played a dominant role in ecology, and arguments have been made that SIMs, which account for the effects of space without specifying spatial positions, have an advantage of being simpler and more broadly applicable, perhaps contributing more to understanding. We address this debate by comparing SEMs and SIMs in examples from the past few decades of modeling research. We argue that, although SIMs have been the dominant approach in the incorporation of space in theoretical ecology, SEMs have unique advantages for addressing pragmatic questions concerning species populations or communities in specific places, because local conditions, such as spatial heterogeneities, organism behaviors, and other contingencies, produce dynamics and patterns that usually cannot be incorporated into simpler SIMs. SEMs are also able to describe mechanisms at the local scale that can create amplifying positive feedbacks at that scale, creating emergent patterns at larger scales, and therefore are important to basic ecological theory. We review the use of SEMs at the level of populations, interacting populations, food webs, and ecosystems and argue that SEMs are not only essential in pragmatic issues, but must play a role in the understanding of causal relationships on landscapes.

  13. Integrating remote sensing and spatially explicit epidemiological modeling

    Science.gov (United States)

    Finger, Flavio; Knox, Allyn; Bertuzzo, Enrico; Mari, Lorenzo; Bompangue, Didier; Gatto, Marino; Rinaldo, Andrea

    2015-04-01

    Spatially explicit epidemiological models are a crucial tool for the prediction of epidemiological patterns in time and space as well as for the allocation of health care resources. In addition they can provide valuable information about epidemiological processes and allow for the identification of environmental drivers of the disease spread. Most epidemiological models rely on environmental data as inputs. They can either be measured in the field by the means of conventional instruments or using remote sensing techniques to measure suitable proxies of the variables of interest. The later benefit from several advantages over conventional methods, including data availability, which can be an issue especially in developing, and spatial as well as temporal resolution of the data, which is particularly crucial for spatially explicit models. Here we present the case study of a spatially explicit, semi-mechanistic model applied to recurring cholera outbreaks in the Lake Kivu area (Democratic Republic of the Congo). The model describes the cholera incidence in eight health zones on the shore of the lake. Remotely sensed datasets of chlorophyll a concentration in the lake, precipitation and indices of global climate anomalies are used as environmental drivers. Human mobility and its effect on the disease spread is also taken into account. Several model configurations are tested on a data set of reported cases. The best models, accounting for different environmental drivers, and selected using the Akaike information criterion, are formally compared via cross validation. The best performing model accounts for seasonality, El Niño Southern Oscillation, precipitation and human mobility.

  14. A Generic Individual-Based Spatially Explicit Model as a Novel Tool for Investigating Insect-Plant Interactions: A Case Study of the Behavioural Ecology of Frugivorous Tephritidae

    OpenAIRE

    Ming Wang; Bronwen Cribb; Clarke, Anthony R.; Jim Hanan

    2016-01-01

    Computational modelling of mechanisms underlying processes in the real world can be of great value in understanding complex biological behaviours. Uptake in general biology and ecology has been rapid. However, it often requires specific data sets that are overly costly in time and resources to collect. The aim of the current study was to test whether a generic behavioural ecology model constructed using published data could give realistic outputs for individual species. An individual-based mo...

  15. A Generic Individual-Based Spatially Explicit Model as a Novel Tool for Investigating Insect-Plant Interactions: A Case Study of the Behavioural Ecology of Frugivorous Tephritidae.

    Directory of Open Access Journals (Sweden)

    Ming Wang

    Full Text Available Computational modelling of mechanisms underlying processes in the real world can be of great value in understanding complex biological behaviours. Uptake in general biology and ecology has been rapid. However, it often requires specific data sets that are overly costly in time and resources to collect. The aim of the current study was to test whether a generic behavioural ecology model constructed using published data could give realistic outputs for individual species. An individual-based model was developed using the Pattern-Oriented Modelling (POM strategy and protocol, based on behavioural rules associated with insect movement choices. Frugivorous Tephritidae (fruit flies were chosen because of economic significance in global agriculture and the multiple published data sets available for a range of species. The Queensland fruit fly (Qfly, Bactrocera tryoni, was identified as a suitable individual species for testing. Plant canopies with modified architecture were used to run predictive simulations. A field study was then conducted to validate our model predictions on how plant architecture affects fruit flies' behaviours. Characteristics of plant architecture such as different shapes, e.g., closed-canopy and vase-shaped, affected fly movement patterns and time spent on host fruit. The number of visits to host fruit also differed between the edge and centre in closed-canopy plants. Compared to plant architecture, host fruit has less contribution to effects on flies' movement patterns. The results from this model, combined with our field study and published empirical data suggest that placing fly traps in the upper canopy at the edge should work best. Such a modelling approach allows rapid testing of ideas about organismal interactions with environmental substrates in silico rather than in vivo, to generate new perspectives. Using published data provides a saving in time and resources. Adjustments for specific questions can be achieved by

  16. A Generic Individual-Based Spatially Explicit Model as a Novel Tool for Investigating Insect-Plant Interactions: A Case Study of the Behavioural Ecology of Frugivorous Tephritidae.

    Science.gov (United States)

    Wang, Ming; Cribb, Bronwen; Clarke, Anthony R; Hanan, Jim

    2016-01-01

    Computational modelling of mechanisms underlying processes in the real world can be of great value in understanding complex biological behaviours. Uptake in general biology and ecology has been rapid. However, it often requires specific data sets that are overly costly in time and resources to collect. The aim of the current study was to test whether a generic behavioural ecology model constructed using published data could give realistic outputs for individual species. An individual-based model was developed using the Pattern-Oriented Modelling (POM) strategy and protocol, based on behavioural rules associated with insect movement choices. Frugivorous Tephritidae (fruit flies) were chosen because of economic significance in global agriculture and the multiple published data sets available for a range of species. The Queensland fruit fly (Qfly), Bactrocera tryoni, was identified as a suitable individual species for testing. Plant canopies with modified architecture were used to run predictive simulations. A field study was then conducted to validate our model predictions on how plant architecture affects fruit flies' behaviours. Characteristics of plant architecture such as different shapes, e.g., closed-canopy and vase-shaped, affected fly movement patterns and time spent on host fruit. The number of visits to host fruit also differed between the edge and centre in closed-canopy plants. Compared to plant architecture, host fruit has less contribution to effects on flies' movement patterns. The results from this model, combined with our field study and published empirical data suggest that placing fly traps in the upper canopy at the edge should work best. Such a modelling approach allows rapid testing of ideas about organismal interactions with environmental substrates in silico rather than in vivo, to generate new perspectives. Using published data provides a saving in time and resources. Adjustments for specific questions can be achieved by refinement of

  17. A comparative study of explicit and implicit modelling of ...

    Indian Academy of Sciences (India)

    Abstract. In this paper, the explicit and implicit modelling of the subsegmental excitation information are experimentally compared. For explicit modelling, the static and dynamic values of the standard Liljencrants–Fant (LF) parameters that model the glottal flow derivative (GFD) are used. A simplified approximation method is.

  18. Explicit Nonlinear Model Predictive Control Theory and Applications

    CERN Document Server

    Grancharova, Alexandra

    2012-01-01

    Nonlinear Model Predictive Control (NMPC) has become the accepted methodology to solve complex control problems related to process industries. The main motivation behind explicit NMPC is that an explicit state feedback law avoids the need for executing a numerical optimization algorithm in real time. The benefits of an explicit solution, in addition to the efficient on-line computations, include also verifiability of the implementation and the possibility to design embedded control systems with low software and hardware complexity. This book considers the multi-parametric Nonlinear Programming (mp-NLP) approaches to explicit approximate NMPC of constrained nonlinear systems, developed by the authors, as well as their applications to various NMPC problem formulations and several case studies. The following types of nonlinear systems are considered, resulting in different NMPC problem formulations: Ø  Nonlinear systems described by first-principles models and nonlinear systems described by black-box models; �...

  19. Recent Advances in Explicit Multiparametric Nonlinear Model Predictive Control

    KAUST Repository

    Domínguez, Luis F.

    2011-01-19

    In this paper we present recent advances in multiparametric nonlinear programming (mp-NLP) algorithms for explicit nonlinear model predictive control (mp-NMPC). Three mp-NLP algorithms for NMPC are discussed, based on which novel mp-NMPC controllers are derived. The performance of the explicit controllers are then tested and compared in a simulation example involving the operation of a continuous stirred-tank reactor (CSTR). © 2010 American Chemical Society.

  20. Explicit pattern recognition models for speech perception

    Science.gov (United States)

    Nearey, Terrance M.

    2003-10-01

    Optimal statistical classification of arbitrary input signals can be obtained, in principle, via a Bayesian classifier, given (perfect) knowledge of the distributions of signal properties for the set of target categories. At least for certain constrained problems, such as the perception of isolated vowels, simple (imperfect) statistical pattern recognition techniques can accurately predict human listeners' performance. This paper sketches several relatively successful case studies of the application of static pattern recognition techniques to speech perception. (Static techniques require inputs of a fixed length, e.g., F1 and F2 for isolated vowels.) Real speech clearly requires dynamic pattern recognition, allowing inputs of arbitrary length. Certain such methods, such as dynamic programming and hidden Markov models, have been widely exploited in automatic speech recognition. The present paper will describe initial attempts to apply variants of such methods to the data from a perception experiment [T. Nearey and R. Smits, J. Acoust. Soc. Am. 111 (2002)] involving the perception of three (VCV) or four (VCCV) segment strings. Practical and conceptual problems in the application of such techniques to human perception will be discussed. [Work supported by SSHRC.

  1. Improvement, Verification, and Refinement of Spatially-Explicit Exposure Models in Risk Assessment - FishRand Spatially-Explicit Bioaccumulation Model Demonstration

    Science.gov (United States)

    2015-08-01

    Explicit Exposure and Ecological Risk Modeling Tools: SEEM and FISHRAND. Platform Presentation at the SETAC Europe Annual Meeting, May 2012, Berlin...suitability as defined by attraction factors;  Lack of direct link to GIS output (e.g., .SHP files) since users much manually draw the exposure fields...predicted while results for DDT are over-predicted. One explanation for this is that DDE is a known metabolite of DDT in both fish and mammals . While the

  2. An explicit method for modeling lossy and dispersive transmission lines

    OpenAIRE

    Palà Schönwälder, Pere; Miró Sans, Joan Maria

    1993-01-01

    In this paper, an explicit -non iterative- method for modeling lossy and dispersive transmission lines, allowing the inclusion of skin-effect parameters is described. This method, based on multipoint Padé approximation, allows direct implementation to obtain models for existing simulation program -such as SPICE-without the need of making use of optimization algorithms at any stage. Examples are given to show that the described procedure yields the same accuracy as other existing techniques th...

  3. Modeling the Explicit Chemistry of Anthropogenic and Biogenic Organic Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Madronich, Sasha [Univ. Corporation for Atmospheric Research, Boulder, CO (United States)

    2015-12-09

    The atmospheric burden of Secondary Organic Aerosols (SOA) remains one of the most important yet uncertain aspects of the radiative forcing of climate. This grant focused on improving our quantitative understanding of SOA formation and evolution, by developing, applying, and improving a highly detailed model of atmospheric organic chemistry, the Generation of Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) model. Eleven (11) publications have resulted from this grant.

  4. Assessment of an Explicit Algebraic Reynolds Stress Model

    Science.gov (United States)

    Carlson, Jan-Renee

    2005-01-01

    This study assesses an explicit algebraic Reynolds stress turbulence model in the in the three-dimensional Reynolds averaged Navier-Stokes (RANS) solver, ISAAC (Integrated Solution Algorithm for Arbitrary Con gurations). Additionally, it compares solutions for two select configurations between ISAAC and the RANS solver PAB3D. This study compares with either direct numerical simulation data, experimental data, or empirical models for several different geometries with compressible, separated, and high Reynolds number flows. In general, the turbulence model matched data or followed experimental trends well, and for the selected configurations, the computational results of ISAAC closely matched those of PAB3D using the same turbulence model.

  5. Explicit estimating equations for semiparametric generalized linear latent variable models

    KAUST Repository

    Ma, Yanyuan

    2010-07-05

    We study generalized linear latent variable models without requiring a distributional assumption of the latent variables. Using a geometric approach, we derive consistent semiparametric estimators. We demonstrate that these models have a property which is similar to that of a sufficient complete statistic, which enables us to simplify the estimating procedure and explicitly to formulate the semiparametric estimating equations. We further show that the explicit estimators have the usual root n consistency and asymptotic normality. We explain the computational implementation of our method and illustrate the numerical performance of the estimators in finite sample situations via extensive simulation studies. The advantage of our estimators over the existing likelihood approach is also shown via numerical comparison. We employ the method to analyse a real data example from economics. © 2010 Royal Statistical Society.

  6. Explicit chiral symmetry breaking in Gross-Neveu type models

    Energy Technology Data Exchange (ETDEWEB)

    Boehmer, Christian

    2011-07-25

    This thesis is devoted to the study of a 1+1-dimensional, fermionic quantum field theory with Lagrangian L= anti {psi}i{gamma}{sup {mu}}{partial_derivative}{sub {mu}}{psi}-m{sub 0} anti {psi}{psi}+(g{sup 2})/(2)(anti {psi}{psi}){sup 2}+(G{sup 2})/(2)(anti {psi}i{gamma}{sub 5}{psi}){sup 2} in the limit of an infinite number of flavors, using semiclassical methods. The main goal of the present work was to see what changes if we allow for explicit chiral symmetry breaking, either by a bare mass term, or a splitting of the scalar and pseudo-scalar coupling constants, or both. In the first case, this becomes the massive NJL{sub 2} model. In the 2nd and 3rd cases we are dealing with a model largely unexplored so far. The first half of this thesis deals with the massive NJL{sub 2} model. Before attacking the phase diagram, it was necessary to determine the baryons of the model. We have carried out full numerical Hartree-Fock calculations including the Dirac sea. The most important result is the first complete phase diagram of the massive NJL{sub 2} model in ({mu},T,{gamma}) space, where {gamma} arises from m{sub 0} through mass renormalization. In the 2nd half of the thesis we have studied a generalization of the massless NJL{sub 2} model with two different (scalar and pseudoscalar) coupling constants, first in the massless version. Renormalization of the 2 coupling constants leads to the usual dynamical mass by dynamical transmutation, but in addition to a novel {xi} parameter interpreted as chiral quenching parameter. As far as baryon structure is concerned, the most interesting result is the fact that the new baryons interpolate between the kink of the GN model and the massless baryon of the NJL{sub 2} model, always carrying fractional baryon number 1/2. The phase diagram of the massless model with 2 coupling constants has again been determined numerically. At zero temperature we have also investigated the massive, generalized GN model with 3 parameters. It is well

  7. SPATIALLY-EXPLICIT BAT IMPACT SCREENING TOOL FOR WIND TURBINE SITING

    Energy Technology Data Exchange (ETDEWEB)

    Versar, Inc.; Exponent, Inc.

    2013-10-28

    As the U.S. seeks to increase energy production from renewable energy sources, development of wind power resources continues to grow. One of the most important ecological issues restricting wind energy development, especially the siting of wind turbines, is the potential adverse effect on bats. High levels of bat fatality have been recorded at a number of wind energy facilities, especially in the eastern United States. The U.S. Department of Energy contracted with Versar, Inc., and Exponent to develop a spatially-explicit site screening tool to evaluate the mortality of bats resulting from interactions (collisions or barotrauma) with wind turbines. The resulting Bat Vulnerability Assessment Tool (BVAT) presented in this report integrates spatial information about turbine locations, bat habitat features, and bat behavior as it relates to possible interactions with turbines. A model demonstration was conducted that focuses on two bat species, the eastern red bat (Lasiurus borealis) and the Indiana bat (Myotis sodalis). The eastern red bat is a relatively common tree-roosting species that ranges broadly during migration in the Eastern U.S., whereas the Indiana bat is regional species that migrates between a summer range and cave hibernacula. Moreover, Indiana bats are listed as endangered, and so the impacts to this species are of particular interest. The model demonstration used conditions at the Mountaineer Wind Energy Center (MWEC), which consists of 44 wind turbines arranged in a linear array near Thomas, West Virginia (Tucker County), to illustrate model functions and not to represent actual or potential impacts of the facility. The turbines at MWEC are erected on the ridge of Backbone Mountain with a nacelle height of 70 meters and a collision area of 72 meters (blade height) or 4,071 meters square. The habitat surrounding the turbines is an Appalachian mixed mesophytic forest. Model sensitivity runs showed that bat mortality in the model was most sensitive to

  8. On Spatially Explicit Models of Cholera Epidemics: Hydrologic controls, environmental drivers, human-mediated transmissions (Invited)

    Science.gov (United States)

    Rinaldo, A.; Bertuzzo, E.; Mari, L.; Righetto, L.; Gatto, M.; Casagrandi, R.; Rodriguez-Iturbe, I.

    2010-12-01

    A recently proposed model for cholera epidemics is examined. The model accounts for local communities of susceptibles and infectives in a spatially explicit arrangement of nodes linked by networks having different topologies. The vehicle of infection (Vibrio cholerae) is transported through the network links which are thought of as hydrological connections among susceptible communities. The mathematical tools used are borrowed from general schemes of reactive transport on river networks acting as the environmental matrix for the circulation and mixing of water-borne pathogens. The results of a large-scale application to the Kwa Zulu (Natal) epidemics of 2001-2002 will be discussed. Useful theoretical results derived in the spatially-explicit context will also be reviewed (like e.g. the exact derivation of the speed of propagation for traveling fronts of epidemics on regular lattices endowed with uniform population density). Network effects will be discussed. The analysis of the limit case of uniformly distributed population density proves instrumental in establishing the overall conditions for the relevance of spatially explicit models. To that extent, it is shown that the ratio between spreading and disease outbreak timescales proves the crucial parameter. The relevance of our results lies in the major differences potentially arising between the predictions of spatially explicit models and traditional compartmental models of the SIR-like type. Our results suggest that in many cases of real-life epidemiological interest timescales of disease dynamics may trigger outbreaks that significantly depart from the predictions of compartmental models. Finally, a view on further developments includes: hydrologically improved aquatic reservoir models for pathogens; human mobility patterns affecting disease propagation; double-peak emergence and seasonality in the spatially explicit epidemic context.

  9. ALADYN - a spatially explicit, allelic model for simulating adaptive dynamics.

    Science.gov (United States)

    Schiffers, Katja H; Travis, Justin Mj

    2014-12-01

    ALADYN is a freely available cross-platform C++ modeling framework for stochastic simulation of joint allelic and demographic dynamics of spatially-structured populations. Juvenile survival is linked to the degree of match between an individual's phenotype and the local phenotypic optimum. There is considerable flexibility provided for the demography of the considered species and the genetic architecture of the traits under selection. ALADYN facilitates the investigation of adaptive processes to spatially and/or temporally changing conditions and the resulting niche and range dynamics. To our knowledge ALADYN is so far the only model that allows a continuous resolution of individuals' locations in a spatially explicit landscape together with the associated patterns of selection.

  10. Quantifying multiple telecouplings using an integrated suite of spatially-explicit tools

    Science.gov (United States)

    Tonini, F.; Liu, J.

    2016-12-01

    Telecoupling is an interdisciplinary research umbrella concept that enables natural and social scientists to understand and generate information for managing how humans and nature can sustainably coexist worldwide. To systematically study telecoupling, it is essential to build a comprehensive set of spatially-explicit tools for describing and quantifying multiple reciprocal socioeconomic and environmental interactions between a focal area and other areas. Here we introduce the Telecoupling Toolbox, a new free and open-source set of tools developed to map and identify the five major interrelated components of the telecoupling framework: systems, flows, agents, causes, and effects. The modular design of the toolbox allows the integration of existing tools and software (e.g. InVEST) to assess synergies and tradeoffs associated with policies and other local to global interventions. We show applications of the toolbox using a number of representative studies that address a variety of scientific and management issues related to telecouplings throughout the world. The results suggest that the toolbox can thoroughly map and quantify multiple telecouplings under various contexts while providing users with an easy-to-use interface. It provides a powerful platform to address globally important issues, such as land use and land cover change, species invasion, migration, flows of ecosystem services, and international trade of goods and products.

  11. Spatially-explicit models of global tree density

    Science.gov (United States)

    Glick, Henry B.; Bettigole, Charlie; Maynard, Daniel S.; Covey, Kristofer R.; Smith, Jeffrey R.; Crowther, Thomas W.

    2016-01-01

    Remote sensing and geographic analysis of woody vegetation provide means of evaluating the distribution of natural resources, patterns of biodiversity and ecosystem structure, and socio-economic drivers of resource utilization. While these methods bring geographic datasets with global coverage into our day-to-day analytic spheres, many of the studies that rely on these strategies do not capitalize on the extensive collection of existing field data. We present the methods and maps associated with the first spatially-explicit models of global tree density, which relied on over 420,000 forest inventory field plots from around the world. This research is the result of a collaborative effort engaging over 20 scientists and institutions, and capitalizes on an array of analytical strategies. Our spatial data products offer precise estimates of the number of trees at global and biome scales, but should not be used for local-level estimation. At larger scales, these datasets can contribute valuable insight into resource management, ecological modelling efforts, and the quantification of ecosystem services. PMID:27529613

  12. Spatially explicit models of divergence and genome hitchhiking.

    Science.gov (United States)

    Flaxman, S M; Feder, J L; Nosil, P

    2012-12-01

    Strong barriers to genetic exchange can exist at divergently selected loci, whereas alleles at neutral loci flow more readily between populations, thus impeding divergence and speciation in the face of gene flow. However, 'divergence hitchhiking' theory posits that divergent selection can generate large regions of differentiation around selected loci. 'Genome hitchhiking' theory suggests that selection can also cause reductions in average genome-wide rates of gene flow, resulting in widespread genomic divergence (rather than divergence only around specific selected loci). Spatial heterogeneity is ubiquitous in nature, yet previous models of genetic barriers to gene flow have explored limited combinations of spatial and selective scenarios. Using simulations of secondary contact of populations, we explore barriers to gene flow in various selective and spatial contexts in continuous, two-dimensional, spatially explicit environments. In general, the effects of hitchhiking are strongest in environments with regular spatial patterning of starkly divergent habitat types. When divergent selection is very strong, the absence of intermediate habitat types increases the effects of hitchhiking. However, when selection is moderate or weak, regular (vs. random) spatial arrangement of habitat types becomes more important than the presence of intermediate habitats per se. We also document counterintuitive processes arising from the stochastic interplay between selection, gene flow and drift. Our results indicate that generalization of results from two-deme models requires caution and increase understanding of the genomic and geographic basis of population divergence. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

  13. Large-eddy simulations with a dynamic explicit vegetation model

    Science.gov (United States)

    Bohrer, G.; Maurer, K.; Chatziefstratiou, E.; Medvigy, D.

    2014-12-01

    We coupled the Regional Atmospheric Modeling System (RAMS)-based Forest Large-Eddy Simulation (RAFLES) and a modified version of the Ecosystem Demography model version 2 (ED2) to form a dynamic, high resolution, physiologically driven large eddy simulation. RAFLES represents both drag and volume restriction by the canopy over an explicit 3-D domain. We conducted a sensitivity analysis of uplift and circulation patterns at the front and back of a rectangular barrier to the representation of the canopy volume. We then used this model to perform a virtual experiment using combinations of realistic heterogeneous canopies and virtual homogenous canopies combined with heterogeneous and homogenous patterns of soil moisture to test the effects of the spatial scaling of soil moisture on the fluxes of momentum, heat, and water in heterogeneous environments at the tree-crown scale. Further simulations were performed to test the combined effects of canopy structure, soil moisture heterogeneity, and soil water availability. We found flux dynamics of momentum, heat, and water to be significantly influenced by canopy structure, soil moisture heterogeneity, and soil water availability. During non-plant-limiting soil-water conditions, we found canopy structure to be the primary driver of tree-crown scale fluxes of momentum, heat, and water, specifically through modification of the ejection sweep dynamics. However, as soil water conditions became limiting for latent heat flux from plants, tree-crown scale fluxes of momentum and heat became influenced by the spatial pattern of soil moisture, whereas soil moisture became a significant driver of tree-crown scale fluxes of water along with canopy structure.

  14. A web-tool to find spatially explicit climate-smart solutions for the sector agriculture

    Science.gov (United States)

    Verzandvoort, Simone; Kuikman, Peter; Walvoort, Dennis

    2017-04-01

    Europe faces the challenge to produce more food and more biomass for the bio-economy, to adapt its agricultural sector to negative consequences of climate change, and to reduce greenhouse gas emissions from agriculture. Climate-smart agriculture (CSA) solutions and technologies improve agriculture's productivity and provide economic growth and stability, increase resilience, and help to reduce GHG emissions from agricultural activities. The Climate Smart Agriculture Booster (CSAb) (http://csabooster.climate-kic.org/) is a Flagship Program under Climate-KIC, aiming to facilitate the adoption of CSA solutions and technologies in the European agro-food sector. This adoption requires spatially explicit, contextual information on farming activities and risks and opportunities related to climate change in regions across Europe. Other spatial information supporting adoption includes Information on where successful implementations were already done, on where CSA would profit from enabling policy conditions, and where markets or business opportunities for selling or purchasing technology and knowledge are located or emerging. The Spatial Solution Finder is a web-based spatial tool aiming to help agri-food companies (supply and processing), authorities or agricultural organisations find CSA solutions and technologies that fit local farmers and regions, and to demonstrate examples of successful implementations as well as expected impact at the farm and regional level. The tool is based on state of the art (geo)datasets of environmental and socio-economic conditions (partly open access, partly derived from previous research) and open source web-technology. The philosophy of the tool is that combining existing datasets with contextual information on the region of interest with personalized information entered by the user provides a suitable basis for offering a basket of options for CSA solutions and technologies. Solutions and technologies are recommended to the user based on

  15. Fuselage Versus Subcomponent Panel Response Correlation Based on ABAQUS Explicit Progressive Damage Analysis Tools

    Science.gov (United States)

    Gould, Kevin E.; Satyanarayana, Arunkumar; Bogert, Philip B.

    2016-01-01

    Analysis performed in this study substantiates the need for high fidelity vehicle level progressive damage analyses (PDA) structural models for use in the verification and validation of proposed sub-scale structural models and to support required full-scale vehicle level testing. PDA results are presented that capture and correlate the responses of sub-scale 3-stringer and 7-stringer panel models and an idealized 8-ft diameter fuselage model, which provides a vehicle level environment for the 7-stringer sub-scale panel model. Two unique skin-stringer attachment assumptions are considered and correlated in the models analyzed: the TIE constraint interface versus the cohesive element (COH3D8) interface. Evaluating different interfaces allows for assessing a range of predicted damage modes, including delamination and crack propagation responses. Damage models considered in this study are the ABAQUS built-in Hashin procedure and the COmplete STress Reduction (COSTR) damage procedure implemented through a VUMAT user subroutine using the ABAQUS/Explicit code.

  16. Explicit contact modeling for surgical computer guidance and simulation

    Science.gov (United States)

    Johnsen, S. F.; Taylor, Z. A.; Clarkson, M.; Thompson, S.; Hu, M.; Gurusamy, K.; Davidson, B.; Hawkes, D. J.; Ourselin, S.

    2012-02-01

    Realistic modelling of mechanical interactions between tissues is an important part of surgical simulation, and may become a valuable asset in surgical computer guidance. Unfortunately, it is also computationally very demanding. Explicit matrix-free FEM solvers have been shown to be a good choice for fast tissue simulation, however little work has been done on contact algorithms for such FEM solvers. This work introduces such an algorithm that is capable of handling both deformable-deformable (soft-tissue interacting with soft-tissue) and deformable-rigid (e.g. soft-tissue interacting with surgical instruments) contacts. The proposed algorithm employs responses computed with a fully matrix-free, virtual node-based version of the model first used by Taylor and Flanagan in PRONTO3D. For contact detection, a bounding-volume hierarchy (BVH) capable of identifying self collisions is introduced. The proposed BVH generation and update strategies comprise novel heuristics to minimise the number of bounding volumes visited in hierarchy update and collision detection. Aside from speed, stability was a major objective in the development of the algorithm, hence a novel method for computation of response forces from C0-continuous normals, and a gradual application of response forces from rate constraints has been devised and incorporated in the scheme. The continuity of the surface normals has advantages particularly in applications such as sliding over irregular surfaces, which occurs, e.g., in simulated breathing. The effectiveness of the scheme is demonstrated on a number of meshes derived from medical image data and artificial test cases.

  17. Spatially explicit bioaccumulation modeling in aquatic environments: Results from 2 demonstration sites.

    Science.gov (United States)

    von Stackelberg, Katherine; Williams, Marc A; Clough, Jonathan; Johnson, Mark S

    2017-11-01

    Bioaccumulation models quantify the relationship between sediment and water exposure concentrations and resulting tissue levels of chemicals in aquatic organisms and represent a key link in the suite of tools used to support decision making at contaminated sediment sites. Predicted concentrations in the aquatic food web provide exposure estimates for human health and ecological risk assessments, which, in turn, provide risk-based frameworks for evaluating potential remedial activities and other management alternatives based on the fish consumption pathway. Despite the widespread use of bioaccumulation models to support remedial decision making, concerns remain about the predictive power of these models. A review of the available literature finds the increased mathematical complexity of typical bioaccumulation model applications is not matched by the deterministic exposure concentrations used to drive the models. We tested a spatially explicit exposure model (FishRand) at 2 nominally contaminated sites and compared results to estimates of bioaccumulation based on conventional, nonspatial techniques, and monitoring data. Differences in predicted fish tissue concentrations across applications were evident, although these demonstration sites were only mildly contaminated and would not warrant management actions on the basis of fish consumption. Nonetheless, predicted tissue concentrations based on the spatially explicit exposure characterization consistently outperformed conventional, nonspatial techniques across a variety of model performance metrics. These results demonstrate the improved predictive power as well as greater flexibility in evaluating the impacts of food web exposure and fish foraging behavior in a heterogeneous exposure environment. Integr Environ Assess Manag 2017;13:1023-1037. © 2017 SETAC. © 2017 SETAC.

  18. Green Infrastructure Modeling Tools

    Science.gov (United States)

    Modeling tools support planning and design decisions on a range of scales from setting a green infrastructure target for an entire watershed to designing a green infrastructure practice for a particular site.

  19. EnviroAtlas: A Spatially Explicit Tool Combining Climate Change Scenarios with Ecosystem Services Indicators

    Science.gov (United States)

    Neale, A. C.; Pickard, B. R.; Megan, M.; Baynes, J.

    2014-12-01

    While discussions of global climate change tend to center on greenhouse gases and sea levelrise, other factors, such as technological developments, land and energy use, economics, and populationgrowth all play a critical role in understanding climate change. There is increasing urgency for methodsto forecast how different sectors, in particular ecosystems and the goods and services they provide, maybe altered as a result of climate change. However, due to their complexity, it is difficult to assess theseecosystem services at a single point in space or time, as they may be influenced by surrounding anddistant patterns of land use and biophysical attributes in addition to climate change. In order to makemeaningful conservation and adaptation choices, specific ecosystem components must be viewed inrelation to future climate information. The US Environmental Protection Agency and its partners, havedeveloped EnviroAtlas, a web-based geospatial tool that allows users to interact with climate changemodeling information while simultaneously providing a range of information and data on differentecosystem goods and services. This can be a useful platform for inquiry about the supply, demand, orbenefits provided by a specific ecosystem service, and to understand the potential impacts to thatecosystem service due to our changing climate. Housing a variety of data in one publicly available toolencourages users to think in new, trans-disciplinary ways that focus on the relationships betweenecosystem services and climate change impacts. By combining many fields of research through this easyto-use interface, the result is a novel tool that is spatially and temporally explicit and enables betterdecision making across multiple sectors. This talk will illustrate how the information presented inEnviroAtlas can be used in research.

  20. Explicit and implicit modeling of nanobubbles in hydrophobic confinement

    Directory of Open Access Journals (Sweden)

    Joachim Dzubiella

    2010-03-01

    Full Text Available Water at normal conditions is a fluid thermodynamically close to the liquid-vapor phase coexistence and features a large surface tension. This combination can lead to interesting capillary phenomena on microscopic scales. Explicit water molecular dynamics (MD computer simulations of hydrophobic solutes, for instance, give evidence of capillary evaporation on nanometer scales, i.e., the formation of nanometer-sized vapor bubbles (nanobubbles between confining hydrophobic surfaces. This phenomenon has been exemplified for solutes with varying complexity, e.g., paraffin plates, coarse-grained homopolymers, biological and solid-state channels, and atomistically resolved proteins. It has been argued that nanobubbles strongly impact interactions in nanofluidic devices, translocation processes, and even in protein stability, function, and folding. As large-scale MD simulations are computationally expensive, the efficient multiscale modeling of nanobubbles and the prediction of their stability poses a formidable task to the'nanophysical' community. Recently, we have presented a conceptually novel and versatile implicit solvent model, namely, the variational implicit solvent model (VISM, which is based on a geometric energy functional. As reviewed here, first solvation studies of simple hydrophobic solutes using VISM coupled with the numerical level-set scheme show promising results, and, in particular, capture nanobubble formation and its subtle competition to local energetic potentials in hydrophobic confinement.Água em condições normais consiste de um fluido termodinamicamente próximo à fase líquida-vapor exibindo alta tensão superficial. Esta combinação conduz a fenômenos capilares interessantes na escala microscópica. Simulações computacionais baseadas em técnicas de Dinâmica Molecular em solutos hidrofóbicos por exemplo fornecem evidências do fenômeno de evaporação capilar em escalas nanométricas dando origem à formação de

  1. Explicitly representing soil microbial processes in Earth system models: Soil microbes in earth system models

    Energy Technology Data Exchange (ETDEWEB)

    Wieder, William R. [Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder Colorado USA; Allison, Steven D. [Department of Ecology and Evolutionary Biology, University of California, Irvine California USA; Department of Earth System Science, University of California, Irvine California USA; Davidson, Eric A. [Appalachian Laboratory, University of Maryland Center for Environmental Science, Frostburg Maryland USA; Georgiou, Katerina [Department of Chemical and Biomolecular Engineering, University of California, Berkeley California USA; Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley California USA; Hararuk, Oleksandra [Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria British Columbia Canada; He, Yujie [Department of Earth System Science, University of California, Irvine California USA; Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette Indiana USA; Hopkins, Francesca [Department of Earth System Science, University of California, Irvine California USA; Jet Propulsion Laboratory, California Institute of Technology, Pasadena California USA; Luo, Yiqi [Department of Microbiology & Plant Biology, University of Oklahoma, Norman Oklahoma USA; Smith, Matthew J. [Computational Science Laboratory, Microsoft Research, Cambridge UK; Sulman, Benjamin [Department of Biology, Indiana University, Bloomington Indiana USA; Todd-Brown, Katherine [Department of Microbiology & Plant Biology, University of Oklahoma, Norman Oklahoma USA; Pacific Northwest National Laboratory, Richland Washington USA; Wang, Ying-Ping [CSIRO Ocean and Atmosphere Flagship, Aspendale Victoria Australia; Xia, Jianyang [Department of Microbiology & Plant Biology, University of Oklahoma, Norman Oklahoma USA; Tiantong National Forest Ecosystem Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai China; Xu, Xiaofeng [Department of Biological Sciences, University of Texas at El Paso, Texas USA

    2015-10-01

    Microbes influence soil organic matter (SOM) decomposition and the long-term stabilization of carbon (C) in soils. We contend that by revising the representation of microbial processes and their interactions with the physicochemical soil environment, Earth system models (ESMs) may make more realistic global C cycle projections. Explicit representation of microbial processes presents considerable challenges due to the scale at which these processes occur. Thus, applying microbial theory in ESMs requires a framework to link micro-scale process-level understanding and measurements to macro-scale models used to make decadal- to century-long projections. Here, we review the diversity, advantages, and pitfalls of simulating soil biogeochemical cycles using microbial-explicit modeling approaches. We present a roadmap for how to begin building, applying, and evaluating reliable microbial-explicit model formulations that can be applied in ESMs. Drawing from experience with traditional decomposition models we suggest: (1) guidelines for common model parameters and output that can facilitate future model intercomparisons; (2) development of benchmarking and model-data integration frameworks that can be used to effectively guide, inform, and evaluate model parameterizations with data from well-curated repositories; and (3) the application of scaling methods to integrate microbial-explicit soil biogeochemistry modules within ESMs. With contributions across scientific disciplines, we feel this roadmap can advance our fundamental understanding of soil biogeochemical dynamics and more realistically project likely soil C response to environmental change at global scales.

  2. Mapping malaria risk and vulnerability in the United Republic of Tanzania: a spatial explicit model.

    Science.gov (United States)

    Hagenlocher, Michael; Castro, Marcia C

    2015-01-01

    Outbreaks of vector-borne diseases (VBDs) impose a heavy burden on vulnerable populations. Despite recent progress in eradication and control, malaria remains the most prevalent VBD. Integrative approaches that take into account environmental, socioeconomic, demographic, biological, cultural, and political factors contributing to malaria risk and vulnerability are needed to effectively reduce malaria burden. Although the focus on malaria risk has increasingly gained ground, little emphasis has been given to develop quantitative methods for assessing malaria risk including malaria vulnerability in a spatial explicit manner. Building on a conceptual risk and vulnerability framework, we propose a spatial explicit approach for modeling relative levels of malaria risk - as a function of hazard, exposure, and vulnerability - in the United Republic of Tanzania. A logistic regression model was employed to identify a final set of risk factors and their contribution to malaria endemicity based on multidisciplinary geospatial information. We utilized a Geographic Information System for the construction and visualization of a malaria vulnerability index and its integration into a spatially explicit malaria risk map. The spatial pattern of malaria risk was very heterogeneous across the country. Malaria risk was higher in Mainland areas than in Zanzibar, which is a result of differences in both malaria entomological inoculation rate and prevailing vulnerabilities. Areas of high malaria risk were identified in the southeastern part of the country, as well as in two distinct "hotspots" in the northwestern part of the country bordering Lake Victoria, while concentrations of high malaria vulnerability seem to occur in the northwestern, western, and southeastern parts of the mainland. Results were visualized using both 10×10 km(2) grids and subnational administrative units. The presented approach makes an important contribution toward a decision support tool. By decomposing malaria

  3. Novel application of explicit dynamics occupancy models to ongoing aquatic invasions

    Science.gov (United States)

    Sepulveda, Adam J.

    2018-01-01

    Identification of suitable habitats, where invasive species can establish, is an important step towards controlling their spread. Accurate identification is difficult for new or slow invaders because unoccupied habitats may be suitable, given enough time for dispersal, while occupied habitats may prove to be unsuitable for establishment.To identify the suitable habitat of a recent invader, I used an explicit dynamics occupancy modelling framework to evaluate habitat covariates related to successful and failed establishments of American bullfrogs (Lithobates catesbeianus) within the Yellowstone River floodplain of Montana, USA from 2012-2016.During this five-year period, bullfrogs failed to establish at most sites they colonized. Bullfrog establishment was most likely to occur and least likely to fail at sites closest to human-modified ponds and lakes and those with emergent vegetation. These habitat covariates were generally associated with the presence of permanent water.Suitable habitat for bullfrog establishment is abundant in the Yellowstone River floodplain, though many sites with suitable habitat remain uncolonized. Thus, the maximum distribution of bullfrogs is much greater than their current distribution.Synthesis and applications. Focused control efforts on habitats with or proximate to permanent waters are most likely to reduce the potential for invasive bullfrog establishment and spread in the Yellowstone River. The novel application of explicit dynamics occupancy models is a useful and widely applicable tool for guiding management efforts towards those habitats where new or slow invaders are most likely to establish and persist.

  4. Explicit equilibria in a kinetic model of gambling

    Science.gov (United States)

    Bassetti, F.; Toscani, G.

    2010-06-01

    We introduce and discuss a nonlinear kinetic equation of Boltzmann type which describes the evolution of wealth in a pure gambling process, where the entire sum of wealths of two agents is up for gambling, and randomly shared between the agents. For this equation the analytical form of the steady states is found for various realizations of the random fraction of the sum which is shared to the agents. Among others, the exponential distribution appears as steady state in case of a uniformly distributed random fraction, while Gamma distribution appears for a random fraction which is Beta distributed. The case in which the gambling game is only conservative-in-the-mean is shown to lead to an explicit heavy tailed distribution.

  5. EXPLICIT CONSTRUCTION OF SUPERCHARGES OF SUPERSYMMETRIC NONLINEAR SIGMA-MODELS IN 1+1 SPACETIME DIMENSIONS

    NARCIS (Netherlands)

    WIEDEMANN, A; MULLERKIRSTEN, HJW

    1993-01-01

    Considering the N = 1 supersymmetry transformations of supersymmetric nonlinear sigma models in 1 + 1 dimensions we construct explicitly conserved Noether currents associated with supersymmetry transformations and derive the associated conserved charges in terms of the basic fields. We compare this

  6. Cholera in the Lake Kivu region (DRC): Integrating remote sensing and spatially explicit epidemiological modeling

    Science.gov (United States)

    Finger, Flavio; Knox, Allyn; Bertuzzo, Enrico; Mari, Lorenzo; Bompangue, Didier; Gatto, Marino; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

    2014-07-01

    Mathematical models of cholera dynamics can not only help in identifying environmental drivers and processes that influence disease transmission, but may also represent valuable tools for the prediction of the epidemiological patterns in time and space as well as for the allocation of health care resources. Cholera outbreaks have been reported in the Democratic Republic of the Congo since the 1970s. They have been ravaging the shore of Lake Kivu in the east of the country repeatedly during the last decades. Here we employ a spatially explicit, inhomogeneous Markov chain model to describe cholera incidence in eight health zones on the shore of the lake. Remotely sensed data sets of chlorophyll a concentration in the lake, precipitation and indices of global climate anomalies are used as environmental drivers in addition to baseline seasonality. The effect of human mobility is also modelled mechanistically. We test several models on a multiyear data set of reported cholera cases. The best fourteen models, accounting for different environmental drivers, and selected using the Akaike information criterion, are formally compared via proper cross validation. Among these, the one accounting for seasonality, El Niño Southern Oscillation, precipitation and human mobility outperforms the others in cross validation. Some drivers (such as human mobility and rainfall) are retained only by a few models, possibly indicating that the mechanisms through which they influence cholera dynamics in the area will have to be investigated further.

  7. Explicit Modeling of Solid Ocean Floor in Shallow Underwater Explosions

    Directory of Open Access Journals (Sweden)

    A.P. Walters

    2013-01-01

    Full Text Available Current practices for modeling the ocean floor in underwater explosion simulations call for application of an inviscid fluid with soil properties. A method for modeling the ocean floor as a Lagrangian solid, vice an Eulerian fluid, was developed in order to determine its effects on underwater explosions in shallow water using the DYSMAS solver. The Lagrangian solid bottom model utilized transmitting boundary segments, exterior nodal forces acting as constraints, and the application of prestress to minimize any distortions into the fluid domain. For simplicity, elastic materials were used in this current effort, though multiple constitutive soil models can be applied to improve the overall accuracy of the model. Even though this method is unable to account for soil cratering effects, it does however provide the distinct advantage of modeling contoured ocean floors such as dredged channels and sloped bottoms absent in Eulerian formulations. The study conducted here showed significant differences among the initial bottom reflections for the different solid bottom contours that were modeled. The most important bottom contour effect was the distortion to the gas bubble and its associated first pulse timing. In addition to its utility in bottom modeling, implementation of the non-reflecting boundary along with realistic material models can be used to drastically reduce the size of current fluid domains.

  8. Are mixed explicit/implicit solvation models reliable for studying phosphate hydrolysis? A comparative study of continuum, explicit and mixed solvation models.

    Energy Technology Data Exchange (ETDEWEB)

    Kamerlin, Shina C. L.; Haranczyk, Maciej; Warshel, Arieh

    2009-05-01

    Phosphate hydrolysis is ubiquitous in biology. However, despite intensive research on this class of reactions, the precise nature of the reaction mechanism remains controversial. In this work, we have examined the hydrolysis of three homologous phosphate diesters. The solvation free energy was simulated by means of either an implicit solvation model (COSMO), hybrid quantum mechanical / molecular mechanical free energy perturbation (QM/MM-FEP) or a mixed solvation model in which N water molecules were explicitly included in the ab initio description of the reacting system (where N=1-3), with the remainder of the solvent being implicitly modelled as a continuum. Here, both COSMO and QM/MM-FEP reproduce Delta Gobs within an error of about 2kcal/mol. However, we demonstrate that in order to obtain any form of reliable results from a mixed model, it is essential to carefully select the explicit water molecules from short QM/MM runs that act as a model for the true infinite system. Additionally, the mixed models tend to be increasingly inaccurate the more explicit water molecules are placed into the system. Thus, our analysis indicates that this approach provides an unreliable way for modelling phosphate hydrolysis in solution.

  9. Spatially explicit models, generalized reproduction numbers and the prediction of patterns of waterborne disease

    Science.gov (United States)

    Rinaldo, A.; Gatto, M.; Mari, L.; Casagrandi, R.; Righetto, L.; Bertuzzo, E.; Rodriguez-Iturbe, I.

    2012-12-01

    still lacking. Here, we show that the requirement that all the local reproduction numbers R0 be larger than unity is neither necessary nor sufficient for outbreaks to occur when local settlements are connected by networks of primary and secondary infection mechanisms. To determine onset conditions, we derive general analytical expressions for a reproduction matrix G0 explicitly accounting for spatial distributions of human settlements and pathogen transmission via hydrological and human mobility networks. At disease onset, a generalized reproduction number Λ0 (the dominant eigenvalue of G0) must be larger than unity. We also show that geographical outbreak patterns in complex environments are linked to the dominant eigenvector and to spectral properties of G0. Tests against data and computations for the 2010 Haiti and 2000 KwaZulu-Natal cholera outbreaks, as well as against computations for metapopulation networks, demonstrate that eigenvectors of G0 provide a synthetic and effective tool for predicting the disease course in space and time. Networked connectivity models, describing the interplay between hydrology, epidemiology and social behavior sustaining human mobility, thus prove to be key tools for emergency management of waterborne infections.

  10. Representing Documents Using an Explicit Model of Their Similarities.

    Science.gov (United States)

    Bartell, Brian T.; And Others

    1995-01-01

    Discussion of the failure of individual keywords to identify conceptual content of documents in retrieval systems highlights Metric Similarity Modeling, a method for creating vector space representation of documents based on modeling target interdocument similarity values. Semantic relatedness, latent semantic indexing, an indexing and retrieval…

  11. Explicit examples of DIM constraints for network matrix models

    Energy Technology Data Exchange (ETDEWEB)

    Awata, Hidetoshi [Graduate School of Mathematics, Nagoya University,Nagoya, 464-8602 (Japan); Kanno, Hiroaki [Graduate School of Mathematics, Nagoya University,Nagoya, 464-8602 (Japan); KMI, Nagoya University,Nagoya, 464-8602 (Japan); Matsumoto, Takuya [Graduate School of Mathematics, Nagoya University,Nagoya, 464-8602 (Japan); Mironov, Andrei [Theory Department, Lebedev Physics Institute,Leninsky pr., 53, Moscow 119991 (Russian Federation); ITEP,Bol.Cheremushkinskaya, 25, Moscow 117218 (Russian Federation); Institute for Information Transmission Problems,Bol.Karetny, 19 (1), Moscow 127994 (Russian Federation); National Research Nuclear University MEPhI,Kashirskoe sh., 31, Moscow 115409 (Russian Federation); Morozov, Alexei [ITEP,Bol.Cheremushkinskaya, 25, Moscow 117218 (Russian Federation); Institute for Information Transmission Problems,Bol.Karetny, 19 (1), Moscow 127994 (Russian Federation); National Research Nuclear University MEPhI,Kashirskoe sh., 31, Moscow 115409 (Russian Federation); Morozov, Andrey [Institute for Information Transmission Problems,Bol.Karetny, 19 (1), Moscow 127994 (Russian Federation); National Research Nuclear University MEPhI,Kashirskoe sh., 31, Moscow 115409 (Russian Federation); Laboratory of Quantum Topology, Chelyabinsk State University,Bratiev Kashirinyh, 129, Chelyabinsk 454001 (Russian Federation); Ohkubo, Yusuke [Graduate School of Mathematics, Nagoya University,Nagoya, 464-8602 (Japan); Zenkevich, Yegor [ITEP,Bol.Cheremushkinskaya, 25, Moscow 117218 (Russian Federation); Institute for Nuclear Research,60-letiya Oktyabrya pr., 7a, Moscow 117312 (Russian Federation); National Research Nuclear University MEPhI,Kashirskoe sh., 31, Moscow 115409 (Russian Federation)

    2016-07-20

    Dotsenko-Fateev and Chern-Simons matrix models, which describe Nekrasov functions for SYM theories in different dimensions, are all incorporated into network matrix models with the hidden Ding-Iohara-Miki (DIM) symmetry. This lifting is especially simple for what we call balanced networks. Then, the Ward identities (known under the names of Virasoro/W-constraints or loop equations or regularity condition for qq-characters) are also promoted to the DIM level, where they all become corollaries of a single identity.

  12. Saturable Lorentz model for fully explicit three-dimensional modeling of nonlinear optics.

    Science.gov (United States)

    Varin, Charles; Bart, Graeme; Emms, Rhys; Brabec, Thomas

    2015-02-09

    Inclusion of the instantaneous Kerr nonlinearity in the FDTD framework leads to implicit equations that have to be solved iteratively. In principle, explicit integration can be achieved with the use of anharmonic oscillator equations, but it tends to be unstable and inappropriate for studying strong-field phenomena like laser filamentation. In this paper, we show that nonlinear susceptibility can be provided instead by a harmonic oscillator driven by a nonlinear force, chosen in a way to reproduce the polarization obtained from the solution of the quantum mechanical two-level equations. The resulting saturable, nonlinearly-driven, harmonic oscillator model reproduces quantitatively the quantum mechanical solutions of harmonic generation in the under-resonant limit, up to the 9th harmonic. Finally, we demonstrate that fully explicit leapfrog integration of the saturable harmonic oscillator is stable, even for the intense laser fields that characterize laser filamentation and high harmonic generation.

  13. FUEL3-D: A Spatially Explicit Fractal Fuel Distribution Model

    Science.gov (United States)

    Russell A. Parsons

    2006-01-01

    Efforts to quantitatively evaluate the effectiveness of fuels treatments are hampered by inconsistencies between the spatial scale at which fuel treatments are implemented and the spatial scale, and detail, with which we model fire and fuel interactions. Central to this scale inconsistency is the resolution at which variability within the fuel bed is considered. Crown...

  14. Advancing environmentally explicit structured population models of plants

    DEFF Research Database (Denmark)

    Ehrlén, Johan; Morris, William; von Euler, Tove

    2016-01-01

    as species distributions and abundances. We searched the literature for studies that have linked abiotic and biotic environmental factors to vital rates and, using structured demographic models, population growth rates of plants. We found 136 studies that had examined the environmental drivers of plant...

  15. The Fidelity of Ocean Models With Explicit Eddies (Chapter 17)

    Energy Technology Data Exchange (ETDEWEB)

    McClean, J; Jayne, S; Maltrud, M; Ivanova, D

    2007-08-01

    Current practices within the oceanographic community have been reviewed with regard to the use of metrics to assess the realism of the upper-ocean circulation, ventilation processes diagnosed by time-evolving mixed layer depth and mode water formation, and eddy heat fluxes in large-scale fine resolution ocean model simulations. We have striven to understand the fidelity of these simulations in the context of their potential use in future fine-resolution coupled climate system studies. A variety of methodologies are used to assess the veracity of the numerical simulations. Sea surface height variability and the location of western boundary current paths from altimetry have been used routinely as basic indicators of fine-resolution model performance. Drifters and floats have also been used to provide pseudo-Eulerian measures of the mean and variability of surface and sub-surface flows, while statistical comparisons of observed and simulated means have been carried out using James tests. Probability density functions have been used to assess the Gaussian nature of the observed and simulated flows. Length and time scales have been calculated in both Eulerian and Lagrangian frameworks from altimetry and drifters, respectively. Concise measures of multiple model performance have been obtained from Taylor diagrams. The time-evolution of the mixed layer depth at monitoring stations has been compared with simulated time series. Finally, eddy heat fluxes are compared to climatological inferences.

  16. Tuning colloidal interactions in subcritical solvents by solvophobicity: explicit versus implicit modeling.

    Science.gov (United States)

    Dzubiella, J; Chakrabarti, J; Löwen, H

    2009-07-28

    The distance-resolved effective interaction between two colloidal particles in a subcritical solvent is explored both by an explicit and implicit modeling. An implicit solvent approach based on a simple thermodynamic interface model is tested against grand-canonical Monte Carlo computer simulations using explicit Lennard-Jones solvent molecules. Close to liquid-gas coexistence, a joint gas bubble surrounding the colloidal particle pair yields an effective attraction between the colloidal particles, the strength of which can be vastly tuned by the solvophobicity of the colloids. The implicit model is in good agreement with our explicit computer simulations, thus enabling an efficient modeling and evaluation of colloidal interactions and self-assembly in subcritical solvent environments.

  17. Assessing Sustainability of Coral Reef Ecosystem Services using a Spatially-Explicit Decision Support Tool

    Science.gov (United States)

    Forecasting and communicating the potential outcomes of decision options requires support tools that aid in evaluating alternative scenarios in a user-friendly context and that highlight variables relevant to the decision options and valuable stakeholders. Envision is a GIS-base...

  18. Linking climate change and fish conservation efforts using spatially explicit decision support tools

    Science.gov (United States)

    Douglas P. Peterson; Seth J. Wenger; Bruce E. Rieman; Daniel J. Isaak

    2013-01-01

    Fisheries professionals are increasingly tasked with incorporating climate change projections into their decisions. Here we demonstrate how a structured decision framework, coupled with analytical tools and spatial data sets, can help integrate climate and biological information to evaluate management alternatives. We present examples that link downscaled climate...

  19. Explicit State Model Checking with Generalized Büchi and Rabin Automata

    NARCIS (Netherlands)

    Bloemen, Vincent; Duret-Lutz, Alexandre; Pol, Jaco van de

    In the automata theoretic approach to explicit state LTL model checking, the synchronized product of the model and an automaton that represents the negated formula is checked for emptiness. In practice, a (transition-based generalized) Büchi automaton (TGBA) is used for this procedure. This paper

  20. Explicit modeling the progressive interface damage in fibrous composite: Analytical vs. numerical approach

    DEFF Research Database (Denmark)

    Kushch, V.I.; Shmegera, S.V.; Mishnaevsky, Leon

    2011-01-01

    Two micromechanical, representative unit cell type models of fiber reinforced composite (FRC) are applied to simulate explicitly onset and accumulation of scattered local damage in the form of interface debonding. The first model is based on the analytical, multipole expansion type solution...

  1. An Explicit Formula for Symmetric Polynomials Related to the Eigenfunctions of Calogero-Sutherland Models

    Directory of Open Access Journals (Sweden)

    Martin Hallnäs

    2007-03-01

    Full Text Available We review a recent construction of an explicit analytic series representation for symmetric polynomials which up to a groundstate factor are eigenfunctions of Calogero-Sutherland type models. We also indicate a generalisation of this result to polynomials which give the eigenfunctions of so-called 'deformed' Calogero-Sutherland type models.

  2. A compact explicit DC model for short channel Gate-All-Around junctionless MOSFETs

    Science.gov (United States)

    Lime, François; Ávila-Herrera, Fernando; Cerdeira, Antonio; Iñiguez, Benjamín

    2017-05-01

    In this paper we provide solutions to update a long channel model in order to take into account the short channel effects. The presented model is for the junctionless GAA MOSFETs. The resulting model is analytical, explicit and valid for depletion and accumulation regimes, and consists of simple physically based equations, for better understanding of this device, and also easier implementation and better computation speed as a compact model. The agreement with TCAD simulations is very good.

  3. An Efficient Explicit-time Description Method for Timed Model Checking

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2009-12-01

    Full Text Available Timed model checking, the method to formally verify real-time systems, is attracting increasing attention from both the model checking community and the real-time community. Explicit-time description methods verify real-time systems using general model constructs found in standard un-timed model checkers. Lamport proposed an explicit-time description method using a clock-ticking process (Tick to simulate the passage of time together with a group of global variables to model time requirements. Two methods, the Sync-based Explicit-time Description Method using rendezvous synchronization steps and the Semaphore-based Explicit-time Description Method using only one global variable were proposed; they both achieve better modularity than Lamport's method in modeling the real-time systems. In contrast to timed automata based model checkers like UPPAAL, explicit-time description methods can access and store the current time instant for future calculations necessary for many real-time systems, especially those with pre-emptive scheduling. However, the Tick process in the above three methods increments the time by one unit in each tick; the state spaces therefore grow relatively fast as the time parameters increase, a problem when the system's time period is relatively long. In this paper, we propose a more efficient method which enables the Tick process to leap multiple time units in one tick. Preliminary experimental results in a high performance computing environment show that this new method significantly reduces the state space and improves both the time and memory efficiency.

  4. Comparing approaches to spatially explicit ecosystem service modeling: a case study from the San Pedro River, Arizona

    Science.gov (United States)

    Bagstad, Kenneth J.; Semmens, Darius J.; Winthrop, Robert

    2013-01-01

    Although the number of ecosystem service modeling tools has grown in recent years, quantitative comparative studies of these tools have been lacking. In this study, we applied two leading open-source, spatially explicit ecosystem services modeling tools – Artificial Intelligence for Ecosystem Services (ARIES) and Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) – to the San Pedro River watershed in southeast Arizona, USA, and northern Sonora, Mexico. We modeled locally important services that both modeling systems could address – carbon, water, and scenic viewsheds. We then applied managerially relevant scenarios for urban growth and mesquite management to quantify ecosystem service changes. InVEST and ARIES use different modeling approaches and ecosystem services metrics; for carbon, metrics were more similar and results were more easily comparable than for viewsheds or water. However, findings demonstrate similar gains and losses of ecosystem services and conclusions when comparing effects across our scenarios. Results were more closely aligned for landscape-scale urban-growth scenarios and more divergent for a site-scale mesquite-management scenario. Follow-up studies, including testing in different geographic contexts, can improve our understanding of the strengths and weaknesses of these and other ecosystem services modeling tools as they move closer to readiness for supporting day-to-day resource management.

  5. Scaling-up spatially-explicit ecological models using graphics processors

    NARCIS (Netherlands)

    Koppel, Johan van de; Gupta, Rohit; Vuik, Cornelis

    2011-01-01

    How the properties of ecosystems relate to spatial scale is a prominent topic in current ecosystem research. Despite this, spatially explicit models typically include only a limited range of spatial scales, mostly because of computing limitations. Here, we describe the use of graphics processors to

  6. An explicit quantum chemical method for modeling large solvation shells applied to aminocoumarin C151

    NARCIS (Netherlands)

    Neugebauer, J.; Jacob, C.R.; Wesolowski, T.A.; Baerends, E.J.

    2005-01-01

    The absorption spectra of aminocoumarin C151 in water and n-hexane solution are investigated by an explicit quantum chemical solvent model. We improved the efficiency of the frozen-density embedding scheme, as used in a former study on solvatochromism (J. Chem. Phys. 2005, 122, 094115) to describe

  7. Explicit linear regressive model structures for estimation, prediction and experimental design in compartmental diffusive systems

    NARCIS (Netherlands)

    Vries, Dirk; Keesman, Karel; Zwart, Heiko J.

    2006-01-01

    A linear regressive model structure and output predictor, both in algebraic form, are deduced from an LTI state space system with certain properties without the need of direct matrix inversion. On the basis of this, explicit expressions of parametric sensitivities are given. As an example, a

  8. Dynamic optimization and robust explicit model predictive control of hydrogen storage tank

    KAUST Repository

    Panos, C.

    2010-09-01

    We present a general framework for the optimal design and control of a metal-hydride bed under hydrogen desorption operation. The framework features: (i) a detailed two-dimension dynamic process model, (ii) a design and operational dynamic optimization step, and (iii) an explicit/multi-parametric model predictive controller design step. For the controller design, a reduced order approximate model is obtained, based on which nominal and robust multi-parametric controllers are designed. © 2010 Elsevier Ltd.

  9. Spatially explicit multimedia fate models for pollutants in Europe: state of the art and perspectives.

    Science.gov (United States)

    Pistocchi, A; Sarigiannis, D A; Vizcaino, P

    2010-08-15

    A review by Hollander et al. (in preparation), discusses the relative potentials, advantages and shortcomings of spatial and non spatial models of chemical fate, highlighting that spatially explicit models may be needed for specific purposes. The present paper reviews the state of the art in spatially explicit chemical fate and transport modeling in Europe. We summarize the three main approaches currently adopted in spatially explicit modeling, namely (1) multiple box models, (2) numerical solutions of simultaneous advection-dispersion equations (ADE) in air, soil and water, and (3) the development of meta-models. As all three approaches experience limitations, we describe in further detail geographic information system (GIS)-based modeling as an alternative approach allowing a simple, yet spatially explicit description of chemical fate. We review the input data needed, and the options available for their retrieval at the European scale. We also discuss the importance of, and limitations in model evaluation. We observe that the high uncertainty in chemical emissions and physico-chemical behavior in the environment make realistic simulations difficult to obtain. Therefore we envisage a shift in model use from process simulation to hypothesis testing, in which explaining the discrepancies between observed and computed chemical concentrations in the environment takes importance over prediction per se. This shift may take advantage of using simple models in GIS with residual uses of complex models for detailed studies. It also calls for tighter joint interpretation of models and spatially distributed monitoring datasets, and more refined spatial representation of environmental drivers such as landscape and climate variables, and better emission estimates. In summary, we conclude that the problem is not "how to compute" (i.e. emphasis on numerical methods, spatial/temporal discretization, quantitative uncertainty and sensitivity analysis...) but "what to compute" (i

  10. Transient modeling/analysis of hyperbolic heat conduction problems employing mixed implicit-explicit alpha method

    Science.gov (United States)

    Tamma, Kumar K.; D'Costa, Joseph F.

    1991-01-01

    This paper describes the evaluation of mixed implicit-explicit finite element formulations for hyperbolic heat conduction problems involving non-Fourier effects. In particular, mixed implicit-explicit formulations employing the alpha method proposed by Hughes et al. (1987, 1990) are described for the numerical simulation of hyperbolic heat conduction models, which involves time-dependent relaxation effects. Existing analytical approaches for modeling/analysis of such models involve complex mathematical formulations for obtaining closed-form solutions, while in certain numerical formulations the difficulties include severe oscillatory solution behavior (which often disguises the true response) in the vicinity of the thermal disturbances, which propagate with finite velocities. In view of these factors, the alpha method is evaluated to assess the control of the amount of numerical dissipation for predicting the transient propagating thermal disturbances. Numerical test models are presented, and pertinent conclusions are drawn for the mixed-time integration simulation of hyperbolic heat conduction models involving non-Fourier effects.

  11. The effects of incorporating vehicle acceleration explicitly into a microscopic traffic simulation model

    Directory of Open Access Journals (Sweden)

    Burger, A. P.

    2013-08-01

    Full Text Available Explicitly incorporating individual vehicle acceleration into a traffic simulation model is not a trivial task, and typically results in a considerable increase in model complexity. For this reason, alternative implicit techniques have been introduced in the literature to compensate for the delay times associated with acceleration. In this paper, the claim is investigated that these implicit modelling techniques adequately account for the time delays due to vehicle acceleration; the modelling techniques are implemented in a simulated environment, and compared with models in which vehicle acceleration has been incorporated explicitly for a number of traffic network topologies and traffic densities. It is found that considerable discrepancies may result between the two approaches.

  12. Numerical modeling of the boundary layer Ekman using explicit algebraic turbulence model

    Science.gov (United States)

    Kurbatskii, Albert; Kurbatskaya, Lyudmila

    2017-10-01

    Modeling turbulence is an important object of environmental sciences for describing an essential turbulent transport of heat and momentum in the boundary layer of the atmosphere. The many turbulence model used in the simulation of flows in the environment, based on the concept of eddy viscosity, and buoyancy effects are often included in the expression for the turbulent fluxes through empirical functions, based on the similarity theory of Monin-Obukhov, fair, strictly speaking, only in the surface layer. Furthermore, significant progress has been made in recent years in the development broader than standard hypothesis turbulent viscosity models for the eddy diffusivity momentum and heat, as a result of the recording of differential equations for the Reynolds stresses and vector turbulent heat flux in a weakly-equilibrium approximation, which neglects advection and the diffusion of certain dimensionless quantities. Explicit algebraic model turbulent Reynolds stresses and heat flux vector for the planetary boundary layer is tested in the neutral atmospheric boundary layer over the homogeneous rough surface. The present algebraic model of turbulence built on physical principles RANS (Reynolds Average Navier Stokes) approach for stratified turbulence uses three prognostic equations and shows correct reproduction of the main characteristics of the Ekman neutral planetary boundary layer (PBL): the components average of wind velocity, the angle of wind turn, turbulence statistics. Test calculations shows that this turbulence model can be used for the purposeful researches of the atmospheric boundary layer for solving of various problems of the environment.

  13. Dynamic modeling and explicit/multi-parametric MPC control of pressure swing adsorption systems

    KAUST Repository

    Khajuria, Harish

    2011-01-01

    Pressure swing adsorption (PSA) is a flexible, albeit complex gas separation system. Due to its inherent nonlinear nature and discontinuous operation, the design of a model based PSA controller, especially with varying operating conditions, is a challenging task. This work focuses on the design of an explicit/multi-parametric model predictive controller for a PSA system. Based on a system involving four adsorbent beds separating 70% H2, 30% CH4 mixture into high purity hydrogen, the key controller objective is to fast track H2 purity to a set point value of 99.99%. To perform this task, a rigorous and systematic framework is employed. First, a high fidelity detailed dynamic model is built to represent the system\\'s real operation, and understand its dynamic behavior. The model is then used to derive appropriate linear models by applying suitable system identification techniques. For the reduced models, a model predictive control (MPC) step is formulated, where latest developments in multi-parametric programming and control are applied to derive a novel explicit MPC controller. To test the performance of the designed controller, closed loop simulations are performed where the dynamic model is used as the virtual plant. Comparison studies of the derived explicit MPC controller are also performed with conventional PID controllers. © 2010 Elsevier Ltd. All rights reserved.

  14. The development of a spatially explicit model to estimate radiocaesium body burdens in raccoons (Procyon lotor) for ecological risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Gaines, Karen F. [University of South Carolina, Norman J. Arnold School of Public Health, Columbia, SC 29208 (United States) and University of Georgia, Savannah River Ecology Laboratory, Aiken, SC 29802 (United States) and Consortium for Risk Evaluation with Stakeholder Participation, Environmental and Occupational Health Sciences Institute, Piscataway, NJ (United States)]. E-mail: kfgaines@usd.edu; Boring, C. Shane [Consortium for Risk Evaluation with Stakeholder Participation, Environmental and Occupational Health Sciences Institute, Piscataway, NJ (United States); Division of Life Sciences, Rutgers University, Piscataway, NJ (United States); Porter, Dwayne E. [University of South Carolina, Norman J. Arnold School of Public Health, Columbia, SC 29208 (United States)

    2005-04-01

    A spatially explicit model of raccoon (Procyon lotor) distribution for the U.S. Department of Energy's (DOE) Savannah River Site (SRS) in west-central South Carolina was developed using data from a raccoon radio-telemetry study and visualized within a Geographic Information System (GIS). An inductive approach was employed to develop three sub-models using the ecological requirements of raccoons studied in the following habitats: (1) man-made reservoirs (2) bottomland hardwood/riverine systems, and (3) isolated wetland systems. Logistic regression was used to derive probabilistic resource selection functions using habitat compositional data and landscape metrics. The final distribution model provides a spatially explicit probability (likelihood of being in an area) surface for male raccoons. The model is a stand-alone tool consisting of algorithms independent of the specific GIS data layers to which they were derived. The model was then used to predict contaminant burdens in raccoons inhabiting a riverine system contaminated with radiocaesium ({sup 137}Cs). The predicted {sup 137}Cs burdens were less than if one would assume homogeneous use of the contaminated areas. This modelling effort provides a template for DOE managed lands and other large government facilities to establish a framework for site-specific ecological assessments that use wildlife species as endpoints.

  15. ANOSPEX: a stochastic, spatially explicit model for studying Anopheles metapopulation dynamics.

    Directory of Open Access Journals (Sweden)

    Olugbenga O Oluwagbemi

    Full Text Available Anopheles mosquitoes transmit malaria, a major public health problem among many African countries. One of the most effective methods to control malaria is by controlling the Anopheles mosquito vectors that transmit the parasites. Mathematical models have both predictive and explorative utility to investigate the pros and cons of different malaria control strategies. We have developed a C++ based, stochastic spatially explicit model (ANOSPEX; Ano pheles Spatially-Explicit to simulate Anopheles metapopulation dynamics. The model is biologically rich, parameterized by field data, and driven by field-collected weather data from Macha, Zambia. To preliminarily validate ANOSPEX, simulation results were compared to field mosquito collection data from Macha; simulated and observed dynamics were similar. The ANOSPEX model will be useful in a predictive and exploratory manner to develop, evaluate and implement traditional and novel strategies to control malaria, and for understanding the environmental forces driving Anopheles population dynamics.

  16. Tools for Model Evaluation

    DEFF Research Database (Denmark)

    Olesen, H. R.

    1998-01-01

    Proceedings of the Twenty-Second NATO/CCMS International Technical Meeting on Air Pollution Modeling and Its Application, held June 6-10, 1997, in Clermont-Ferrand, France.......Proceedings of the Twenty-Second NATO/CCMS International Technical Meeting on Air Pollution Modeling and Its Application, held June 6-10, 1997, in Clermont-Ferrand, France....

  17. Efficient modeling of sun/shade canopy radiation dynamics explicitly accounting for scattering

    Directory of Open Access Journals (Sweden)

    P. Bodin

    2012-04-01

    Full Text Available The separation of global radiation (Rg into its direct (Rb and diffuse constituents (Rg is important when modeling plant photosynthesis because a high Rd:Rg ratio has been shown to enhance Gross Primary Production (GPP. To include this effect in vegetation models, the plant canopy must be separated into sunlit and shaded leaves. However, because such models are often too intractable and computationally expensive for theoretical or large scale studies, simpler sun-shade approaches are often preferred. A widely used and computationally efficient sun-shade model was developed by Goudriaan (1977 (GOU. However, compared to more complex models, this model's realism is limited by its lack of explicit treatment of radiation scattering.

    Here we present a new model based on the GOU model, but which in contrast explicitly simulates radiation scattering by sunlit leaves and the absorption of this radiation by the canopy layers above and below (2-stream approach. Compared to the GOU model our model predicts significantly different profiles of scattered radiation that are in better agreement with measured profiles of downwelling diffuse radiation. With respect to these data our model's performance is equal to a more complex and much slower iterative radiation model while maintaining the simplicity and computational efficiency of the GOU model.

  18. Explicit modeling of ancestry improves polygenic risk scores and BLUP prediction

    Science.gov (United States)

    Chen, Chia-Yen; Han, Jiali; Hunter, David J.; Kraft, Peter; Price, Alkes L.

    2016-01-01

    Polygenic prediction using genome-wide SNPs can provide high prediction accuracy for complex traits. Here, we investigate the question of how to account for genetic ancestry when conducting polygenic prediction. We show that the accuracy of polygenic prediction in structured populations may be partly due to genetic ancestry. However, we hypothesized that explicitly modeling ancestry could improve polygenic prediction accuracy. We analyzed three GWAS of hair color, tanning ability and basal cell carcinoma (BCC) in European Americans (sample size from 7,440 to 9,822) and considered two widely used polygenic prediction approaches: polygenic risk scores (PRS) and Best Linear Unbiased Prediction (BLUP). We compared polygenic prediction without correction for ancestry to polygenic prediction with ancestry as a separate component in the model. In 10-fold cross-validation using the PRS approach, the R2 for hair color increased by 66% (0.0456 to 0.0755; pancestry, which prevents ancestry effects from entering into each SNP effect and being over-weighted. Surprisingly, explicitly modeling ancestry produces a similar improvement when using the BLUP approach, which fits all SNPs simultaneously in a single variance component and causes ancestry to be underweighted. We validate our findings via simulations, which show that the differences in prediction accuracy will increase in magnitude as sample sizes increase. In summary, our results show that explicitly modeling ancestry can be important in both PRS and BLUP prediction. PMID:25995153

  19. Additive Dose Response Models: Explicit Formulation and the Loewe Additivity Consistency Condition

    Directory of Open Access Journals (Sweden)

    Simone Lederer

    2018-02-01

    Full Text Available High-throughput techniques allow for massive screening of drug combinations. To find combinations that exhibit an interaction effect, one filters for promising compound combinations by comparing to a response without interaction. A common principle for no interaction is Loewe Additivity which is based on the assumption that no compound interacts with itself and that two doses from different compounds having the same effect are equivalent. It then should not matter whether a component is replaced by the other or vice versa. We call this assumption the Loewe Additivity Consistency Condition (LACC. We derive explicit and implicit null reference models from the Loewe Additivity principle that are equivalent when the LACC holds. Of these two formulations, the implicit formulation is the known General Isobole Equation (Loewe, 1928, whereas the explicit one is the novel contribution. The LACC is violated in a significant number of cases. In this scenario the models make different predictions. We analyze two data sets of drug screening that are non-interactive (Cokol et al., 2011; Yadav et al., 2015 and show that the LACC is mostly violated and Loewe Additivity not defined. Further, we compare the measurements of the non-interactive cases of both data sets to the theoretical null reference models in terms of bias and mean squared error. We demonstrate that the explicit formulation of the null reference model leads to smaller mean squared errors than the implicit one and is much faster to compute.

  20. Explicit calculation of indirect global warming potentials for halons using atmospheric models

    Directory of Open Access Journals (Sweden)

    D. J. Wuebbles

    2009-11-01

    Full Text Available The concept of Global Warming Potentials (GWPs has been extensively used in policy consideration as a relative index for comparing the climate impact of an emitted greenhouse gas (GHG, relative to carbon dioxide with equal mass emissions. Ozone depletion due to emission of chlorinated or brominated halocarbons leads to cooling of the climate system in the opposite direction to the direct warming contribution by halocarbons as GHGs. This cooling is a key indirect effect of the halocarbons on climatic radiative forcing, which is accounted for by indirect GWPs. With respect to climate, it is critical to understand net influences considering direct warming and indirect cooling effects especially for Halons due to the greater ozone-depleting efficiency of bromine over chlorine. Until now, the indirect GWPs have been calculated using a parameterized approach based on the concept of Equivalent Effective Stratospheric Chlorine (EESC and the observed ozone depletion over the last few decades. As a step towards obtaining indirect GWPs through a more robust approach, we use atmospheric models to explicitly calculate the indirect GWPs of Halon-1211 and Halon-1301 for a 100-year time horizon. State-of-the-art global chemistry-transport models (CTMs were used as the computational tools to derive more realistic ozone depletion changes caused by an added pulse emission of the two major Halons at the surface. The radiative forcings on climate from the ozone changes have been calculated for indirect GWPs using an atmospheric radiative transfer model (RTM. The simulated temporal variations of global average total column Halons after a pulse perturbation follow an exponential decay with an e-folding time which is consistent with the expected chemical lifetimes of the Halons. Our calculated indirect GWPs for the two Halons are much smaller than those from past studies but are within a single standard deviation of WMO (2007 values and the direct GWP values derived

  1. Implicit-Explicit Time Integration Methods for Non-hydrostatic Atmospheric Models

    Science.gov (United States)

    Gardner, D. J.; Guerra, J. E.; Hamon, F. P.; Reynolds, D. R.; Ullrich, P. A.; Woodward, C. S.

    2016-12-01

    The Accelerated Climate Modeling for Energy (ACME) project is developing a non-hydrostatic atmospheric dynamical core for high-resolution coupled climate simulations on Department of Energy leadership class supercomputers. An important factor in computational efficiency is avoiding the overly restrictive time step size limitations of fully explicit time integration methods due to the stiffest modes present in the model (acoustic waves). In this work we compare the accuracy and performance of different Implicit-Explicit (IMEX) splittings of the non-hydrostatic equations and various Additive Runge-Kutta (ARK) time integration methods. Results utilizing the Tempest non-hydrostatic atmospheric model and the ARKode package show that the choice of IMEX splitting and ARK scheme has a significant impact on the maximum stable time step size as well as solution quality. Horizontally Explicit Vertically Implicit (HEVI) approaches paired with certain ARK methods lead to greatly improved runtimes. With effective preconditioning IMEX splittings that incorporate some implicit horizontal dynamics can be competitive with HEVI results. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-699187

  2. CPsuperH2.3: an Updated Tool for Phenomenology in the MSSM with Explicit CP Violation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.S.; Carena, M.; Ellis, J.; Pilaftsis, A.; Wagner, C.E.M.

    2013-04-01

    We describe the Fortran code CPsuperH2.3, which incorporates the following updates compared with its predecessor CPsuperH2.0. It implements improved calculations of the Higgs-boson masses and mixing including stau contributions and finite threshold effects on the tau-lepton Yukawa coupling. It incorporates the LEP limits on the processes e^+e^-->H_iZ,H_iH_j and the CMS limits on H_i->@t@?@t obtained from 4.6 fb^-^1 of data at a center-of-mass energy of 7 TeV. It also includes the decay mode H_i->Z@c and the Schiff-moment contributions to the electric dipole moments of Mercury and Radium 225, with several calculational options for the case of Mercury. These additions make CPsuperH2.3 a suitable tool for analyzing possible CP-violating effects in the MSSM in the era of the LHC and a new generation of EDM experiments. Program summary: Program title: CPsuperH2.3 Catalogue identifier: ADSR_v3_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSR_v3_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 24058 No. of bytes in distributed program, including test data, etc.: 158721 Distribution format: tar.gz Programming language: Fortran77. Computer: PC running under Linux and computers in Unix environment. Operating system: Linux. RAM: 32 MB Classification: 11.1. Does the new version supersede the previous version?: Yes Catalogue identifier of previous version: ADSR_v2_0 Journal reference of previous version: Comput. Phys. Comm. 180(2009)312 Nature of problem: The calculations of mass spectrum, decay widths and branching ratios of the neutral and charged Higgs bosons in the Minimal Supersymmetric Standard Model with explicit CP violation have been improved. The program is based on renormalization-group-improved diagrammatic calculations that include dominant higher

  3. An Explicit Approach Toward Modeling Thermo-Coupled Deformation Behaviors of SMPs

    Directory of Open Access Journals (Sweden)

    Hao Li

    2017-03-01

    Full Text Available A new elastoplastic J 2 -flow models with thermal effects is proposed toward simulating thermo-coupled finite deformation behaviors of shape memory polymers. In this new model, an elastic potential evolving with development of plastic flow is incorporated to characterize the stress-softening effect at unloading and, moreover, thermo-induced plastic flow is introduced to represent the strain recovery effect at heating. It is shown that any given test data for both effects may be accurately simulated by means of direct and explicit procedures. Numerical examples for model predictions compare well with test data in literature.

  4. A two-dimensional model that employs explicit and implicit attitudes to characterize prejudice.

    Science.gov (United States)

    Son Hing, Leanne S; Chung-Yan, Greg A; Hamilton, Leah K; Zanna, Mark P

    2008-06-01

    In the authors' 2-dimensional model of prejudice, explicit and implicit attitudes are used to create 4 profiles: truly low prejudiced (TLP: double lows), aversive racists (AR: low explicit modern racism/high implicit prejudice), principled conservatives (PC: high explicit modern racism/low implicit prejudice), and modern racists (MR: double highs). Students completed an Asian Modern Racism Scale and an Asian/White Implicit Association Test. The authors compared the 4 groups' prejudice-related ideologies (i.e., egalitarianism/humanism and social conservatism) and economic/political conservatism (Study 1, N=132). The authors also tested whether MR but not PC (Study 2, N=65) and AR but not TLP (Study 3, N=143) are more likely to negatively evaluate an Asian target when attributional ambiguity is high (vs. low). In support of the model, TLP did not hold prejudice-related ideologies and did not discriminate; AR were low in conservatism and demonstrated the attributional-ambiguity effect; PC did not strongly endorse prejudice-related ideologies and did not discriminate; MR strongly endorsed prejudice-related ideologies, were conservative, and demonstrated the attributional-ambiguity effect. The authors discuss implications for operationalizing and understanding the nature of prejudice. (PsycINFO Database Record (c) 2008 APA, all rights reserved).

  5. Explicit model predictive control applications in power systems: an AGC study for an isolated industrial system

    DEFF Research Database (Denmark)

    Jiang, Hao; Lin, Jin; Song, Yonghua

    2016-01-01

    Model predictive control (MPC), that can consider system constraints, is one of the most advanced control technology used nowadays. In power systems, MPC is applied in a way that an optimal control sequence is given every step by an online MPC controller. The main drawback is that the control law...... cannot be evaluated before the MPC controller is put into service. Therefore, system operators may not validate its performances in advance. To overcome this drawback, the explicit MPC (EMPC) method is introduced and applied to obtain an explicit control law. In addition, another major contribution...... is that an improved partition algorithm of EMPC is studied which enables the EMPC method to be extended to a system of large number of state variables and more constraints. A simple single generator single load case is used to illustrate the whole procedure of EMPC and then the EMPC is applied to an actual isolated...

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

    Science.gov (United States)

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

    2005-01-01

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

  7. Explicit all-atom modeling of realistically sized ligand-capped nanocrystals

    KAUST Repository

    Kaushik, Ananth P.

    2012-01-01

    We present a study of an explicit all-atom representation of nanocrystals of experimentally relevant sizes (up to 6 nm), capped with alkyl chain ligands, in vacuum. We employ all-atom molecular dynamics simulation methods in concert with a well-tested intermolecular potential model, MM3 (molecular mechanics 3), for the studies presented here. These studies include determining the preferred conformation of an isolated single nanocrystal (NC), pairs of isolated NCs, and (presaging studies of superlattice arrays) unit cells of NC superlattices. We observe that very small NCs (3 nm) behave differently in a superlattice as compared to larger NCs (6 nm and above) due to the conformations adopted by the capping ligands on the NC surface. Short ligands adopt a uniform distribution of orientational preferences, including some that lie against the face of the nanocrystal. In contrast, longer ligands prefer to interdigitate. We also study the effect of changing ligand length and ligand coverage on the NCs on the preferred ligand configurations. Since explicit all-atom modeling constrains the maximum system size that can be studied, we discuss issues related to coarse-graining the representation of the ligands, including a comparison of two commonly used coarse-grained models. We find that care has to be exercised in the choice of coarse-grained model. The data provided by these realistically sized ligand-capped NCs, determined using explicit all-atom models, should serve as a reference standard for future models of coarse-graining ligands using united atom models, especially for self-assembly processes. © 2012 American Institute of Physics.

  8. Estimating and interpreting migration of Amazonian forests using spatially implicit and semi-explicit neutral models.

    Science.gov (United States)

    Pos, Edwin; Guevara Andino, Juan Ernesto; Sabatier, Daniel; Molino, Jean-François; Pitman, Nigel; Mogollón, Hugo; Neill, David; Cerón, Carlos; Rivas-Torres, Gonzalo; Di Fiore, Anthony; Thomas, Raquel; Tirado, Milton; Young, Kenneth R; Wang, Ophelia; Sierra, Rodrigo; García-Villacorta, Roosevelt; Zagt, Roderick; Palacios Cuenca, Walter; Aulestia, Milton; Ter Steege, Hans

    2017-06-01

    With many sophisticated methods available for estimating migration, ecologists face the difficult decision of choosing for their specific line of work. Here we test and compare several methods, performing sanity and robustness tests, applying to large-scale data and discussing the results and interpretation. Five methods were selected to compare for their ability to estimate migration from spatially implicit and semi-explicit simulations based on three large-scale field datasets from South America (Guyana, Suriname, French Guiana and Ecuador). Space was incorporated semi-explicitly by a discrete probability mass function for local recruitment, migration from adjacent plots or from a metacommunity. Most methods were able to accurately estimate migration from spatially implicit simulations. For spatially semi-explicit simulations, estimation was shown to be the additive effect of migration from adjacent plots and the metacommunity. It was only accurate when migration from the metacommunity outweighed that of adjacent plots, discrimination, however, proved to be impossible. We show that migration should be considered more an approximation of the resemblance between communities and the summed regional species pool. Application of migration estimates to simulate field datasets did show reasonably good fits and indicated consistent differences between sets in comparison with earlier studies. We conclude that estimates of migration using these methods are more an approximation of the homogenization among local communities over time rather than a direct measurement of migration and hence have a direct relationship with beta diversity. As betadiversity is the result of many (non)-neutral processes, we have to admit that migration as estimated in a spatial explicit world encompasses not only direct migration but is an ecological aggregate of these processes. The parameter m of neutral models then appears more as an emerging property revealed by neutral theory instead of

  9. An improved risk-explicit interval linear programming model for pollution load allocation for watershed management.

    Science.gov (United States)

    Xia, Bisheng; Qian, Xin; Yao, Hong

    2017-11-01

    Although the risk-explicit interval linear programming (REILP) model has solved the problem of having interval solutions, it has an equity problem, which can lead to unbalanced allocation between different decision variables. Therefore, an improved REILP model is proposed. This model adds an equity objective function and three constraint conditions to overcome this equity problem. In this case, pollution reduction is in proportion to pollutant load, which supports balanced development between different regional economies. The model is used to solve the problem of pollution load allocation in a small transboundary watershed. Compared with the REILP original model result, our model achieves equity between the upstream and downstream pollutant loads; it also overcomes the problem of greatest pollution reduction, where sources are nearest to the control section. The model provides a better solution to the problem of pollution load allocation than previous versions.

  10. Short-Range Prediction of Monsoon Precipitation by NCMRWF Regional Unified Model with Explicit Convection

    Science.gov (United States)

    Mamgain, Ashu; Rajagopal, E. N.; Mitra, A. K.; Webster, S.

    2017-12-01

    There are increasing efforts towards the prediction of high-impact weather systems and understanding of related dynamical and physical processes. High-resolution numerical model simulations can be used directly to model the impact at fine-scale details. Improvement in forecast accuracy can help in disaster management planning and execution. National Centre for Medium Range Weather Forecasting (NCMRWF) has implemented high-resolution regional unified modeling system with explicit convection embedded within coarser resolution global model with parameterized convection. The models configurations are based on UK Met Office unified seamless modeling system. Recent land use/land cover data (2012-2013) obtained from Indian Space Research Organisation (ISRO) are also used in model simulations. Results based on short-range forecast of both the global and regional models over India for a month indicate that convection-permitting simulations by the high-resolution regional model is able to reduce the dry bias over southern parts of West Coast and monsoon trough zone with more intense rainfall mainly towards northern parts of monsoon trough zone. Regional model with explicit convection has significantly improved the phase of the diurnal cycle of rainfall as compared to the global model. Results from two monsoon depression cases during study period show substantial improvement in details of rainfall pattern. Many categories in rainfall defined for operational forecast purposes by Indian forecasters are also well represented in case of convection-permitting high-resolution simulations. For the statistics of number of days within a range of rain categories between `No-Rain' and `Heavy Rain', the regional model is outperforming the global model in all the ranges. In the very heavy and extremely heavy categories, the regional simulations show overestimation of rainfall days. Global model with parameterized convection have tendency to overestimate the light rainfall days and

  11. Developing Spatially Explicit Habitat Models for Grassland Bird Conservation Planning in the Prairie Pothole Region of North Dakota

    Science.gov (United States)

    Neal D. Niemuth; Michael E. Estey; Charles R. Loesch

    2005-01-01

    Conservation planning for birds is increasingly focused on landscapes. However, little spatially explicit information is available to guide landscape-level conservation planning for many species of birds. We used georeferenced 1995 Breeding Bird Survey (BBS) data in conjunction with land-cover information to develop a spatially explicit habitat model predicting the...

  12. Integrating a Decision Management Tool with UML Modeling Tools

    DEFF Research Database (Denmark)

    Könemann, Patrick

    the development process. In this report, we propose an integration of a decision management and a UML-based modeling tool, based on use cases we distill from a case study: the modeling tool shall show all decisions related to a model and allow its users to extend or update them; the decision management tool shall...

  13. Spatially-Explicit Bayesian Information Entropy Metrics for Calibrating Landscape Transformation Models

    Directory of Open Access Journals (Sweden)

    Kostas Alexandridis

    2013-06-01

    Full Text Available Assessing spatial model performance often presents challenges related to the choice and suitability of traditional statistical methods in capturing the true validity and dynamics of the predicted outcomes. The stochastic nature of many of our contemporary spatial models of land use change necessitate the testing and development of new and innovative methodologies in statistical spatial assessment. In many cases, spatial model performance depends critically on the spatially-explicit prior distributions, characteristics, availability and prevalence of the variables and factors under study. This study explores the statistical spatial characteristics of statistical model assessment of modeling land use change dynamics in a seven-county study area in South-Eastern Wisconsin during the historical period of 1963–1990. The artificial neural network-based Land Transformation Model (LTM predictions are used to compare simulated with historical land use transformations in urban/suburban landscapes. We introduce a range of Bayesian information entropy statistical spatial metrics for assessing the model performance across multiple simulation testing runs. Bayesian entropic estimates of model performance are compared against information-theoretic stochastic entropy estimates and theoretically-derived accuracy assessments. We argue for the critical role of informational uncertainty across different scales of spatial resolution in informing spatial landscape model assessment. Our analysis reveals how incorporation of spatial and landscape information asymmetry estimates can improve our stochastic assessments of spatial model predictions. Finally our study shows how spatially-explicit entropic classification accuracy estimates can work closely with dynamic modeling methodologies in improving our scientific understanding of landscape change as a complex adaptive system and process.

  14. Modeling nitrous oxide production and reduction in soil through explicit representation of denitrification enzyme kinetics.

    Science.gov (United States)

    Zheng, Jianqiu; Doskey, Paul V

    2015-02-17

    An enzyme-explicit denitrification model with representations for pre- and de novo synthesized enzymes was developed to improve predictions of nitrous oxide (N2O) accumulations in soil and emissions from the surface. The metabolic model of denitrification is based on dual-substrate utilization and Monod growth kinetics. Enzyme synthesis/activation was incorporated into each sequential reduction step of denitrification to regulate dynamics of the denitrifier population and the active enzyme pool, which controlled the rate function. Parameterizations were developed from observations of the dynamics of N2O production and reduction in soil incubation experiments. The model successfully reproduced the dynamics of N2O and N2 accumulation in the incubations and revealed an important regulatory effect of denitrification enzyme kinetics on the accumulation of denitrification products. Pre-synthesized denitrification enzymes contributed 20, 13, 43, and 62% of N2O that accumulated in 48 h incubations of soil collected from depths of 0-5, 5-10, 10-15, and 15-25 cm, respectively. An enzyme activity function (E) was defined to estimate the relative concentration of active enzymes and variation in response to environmental conditions. The value of E allows for activities of pre-synthesized denitrification enzymes to be differentiated from de novo synthesized enzymes. Incorporating explicit representations of denitrification enzyme kinetics into biogeochemical models is a promising approach for accurately simulating dynamics of the production and reduction of N2O in soils.

  15. Machine learning of explicit order parameters: From the Ising model to SU(2) lattice gauge theory

    Science.gov (United States)

    Wetzel, Sebastian J.; Scherzer, Manuel

    2017-11-01

    We present a solution to the problem of interpreting neural networks classifying phases of matter. We devise a procedure for reconstructing the decision function of an artificial neural network as a simple function of the input, provided the decision function is sufficiently symmetric. In this case one can easily deduce the quantity by which the neural network classifies the input. The method is applied to the Ising model and SU(2) lattice gauge theory. In both systems we deduce the explicit expressions of the order parameters from the decision functions of the neural networks. We assume no prior knowledge about the Hamiltonian or the order parameters except Monte Carlo-sampled configurations.

  16. Explicit kinetic heterogeneity: mechanistic models for interpretation of labeling data in heterogeneous populations

    Energy Technology Data Exchange (ETDEWEB)

    Ganusov, Vitaly V [Los Alamos National Laboratory

    2008-01-01

    Estimation of division and death rates of lymphocytes in different conditions is vital for quantitative understanding of the immune system. Deuterium, in the form of deuterated glucose or heavy water, can be used to measure rates of proliferation and death of lymphocytes in vivo. Inferring these rates from labeling and delabeling curves has been subject to considerable debate with different groups suggesting different mathematical models for that purpose. We show that the three models that are most commonly used are in fact mathematically identical and differ only in their interpretation of the estimated parameters. By extending these previous models, we here propose a more mechanistic approach for the analysis of data from deuterium labeling experiments. We construct a model of 'kinetic heterogeneity' in which the total cell population consists of many sub-populations with different rates of cell turnover. In this model, for a given distribution of the rates of turnover, the predicted fraction of labeled DNA accumulated and lost can be calculated. Our model reproduces several previously made experimental observations, such as a negative correlation between the length of the labeling period and the rate at which labeled DNA is lost after label cessation. We demonstrate the reliability of the new explicit kinetic heterogeneity model by applying it to artificially generated datasets, and illustrate its usefulness by fitting experimental data. In contrast to previous models, the explicit kinetic heterogeneity model (1) provides a mechanistic way of interpreting labeling data; (2) allows for a non-exponential loss of labeled cells during delabeling, and (3) can be used to describe data with variable labeling length.

  17. Explicit kinetic heterogeneity: mathematical models for interpretation of deuterium labeling of heterogeneous cell populations.

    Directory of Open Access Journals (Sweden)

    Vitaly V Ganusov

    2010-02-01

    Full Text Available Estimation of division and death rates of lymphocytes in different conditions is vital for quantitative understanding of the immune system. Deuterium, in the form of deuterated glucose or heavy water, can be used to measure rates of proliferation and death of lymphocytes in vivo. Inferring these rates from labeling and delabeling curves has been subject to considerable debate with different groups suggesting different mathematical models for that purpose. We show that the three most common models, which are based on quite different biological assumptions, actually predict mathematically identical labeling curves with one parameter for the exponential up and down slope, and one parameter defining the maximum labeling level. By extending these previous models, we here propose a novel approach for the analysis of data from deuterium labeling experiments. We construct a model of "kinetic heterogeneity" in which the total cell population consists of many sub-populations with different rates of cell turnover. In this model, for a given distribution of the rates of turnover, the predicted fraction of labeled DNA accumulated and lost can be calculated. Our model reproduces several previously made experimental observations, such as a negative correlation between the length of the labeling period and the rate at which labeled DNA is lost after label cessation. We demonstrate the reliability of the new explicit kinetic heterogeneity model by applying it to artificially generated datasets, and illustrate its usefulness by fitting experimental data. In contrast to previous models, the explicit kinetic heterogeneity model 1 provides a novel way of interpreting labeling data; 2 allows for a non-exponential loss of labeled cells during delabeling, and 3 can be used to describe data with variable labeling length.

  18. An Object-Oriented Framework for Explicit-State Model Checking

    NARCIS (Netherlands)

    Kattenbelt, M.; Ruys, T.C.; Rensink, Arend; Groot, P.; Serebrenik, A.; van Eekelen, M.

    2007-01-01

    This paper presents a conceptual architecture for an object-oriented framework to support the development of formal veri��?cation tools (i.e. model checkers). The objective of the architecture is to support the reuse of algorithms and to encourage a modular design of tools. The conceptual framework

  19. Predicting continental-scale patterns of bird species richness with spatially explicit models

    DEFF Research Database (Denmark)

    Rahbek, Carsten; Gotelli, Nicholas J; Colwell, Robert K

    2007-01-01

    at a continental scale. We demonstrate that the principal single-factor and composite (species-energy, water-energy and temperature-kinetics) models proposed thus far fail to predict (r(2) ...). These species constitute the bulk of the avifauna and are primary targets for conservation. Climate-driven models performed reasonably well only for species with the largest geographical ranges (fourth quartile) when range cohesion was enforced. Our analyses suggest that present models inadequately explain......The causes of global variation in species richness have been debated for nearly two centuries with no clear resolution in sight. Competing hypotheses have typically been evaluated with correlative models that do not explicitly incorporate the mechanisms responsible for biotic diversity gradients...

  20. A Risk Assessment Example for Soil Invertebrates Using Spatially Explicit Agent-Based Models

    DEFF Research Database (Denmark)

    Reed, Melissa; Alvarez, Tania; Chelinho, Sonia

    2016-01-01

    Current risk assessment methods for measuring the toxicity of plant protection products (PPPs) on soil invertebrates use standardized laboratory conditions to determine acute effects on mortality and sublethal effects on reproduction. If an unacceptable risk is identified at the lower tier...... population models for ubiquitous soil invertebrates (collembolans and earthworms) as refinement options in current risk assessment. Both are spatially explicit agent-based models (ABMs), incorporating individual and landscape variability. The models were used to provide refined risk assessments for different...... application scenarios of a hypothetical pesticide applied to potato crops (full-field spray onto the soil surface [termed “overall”], in-furrow, and soil-incorporated pesticide applications). In the refined risk assessment, the population models suggest that soil invertebrate populations would likely recover...

  1. Simulation of a severe convective storm using a numerical model with explicitly incorporated aerosols

    Science.gov (United States)

    Lompar, Miloš; Ćurić, Mladjen; Romanic, Djordje

    2017-09-01

    Despite an important role the aerosols play in all stages of cloud lifecycle, their representation in numerical weather prediction models is often rather crude. This paper investigates the effects the explicit versus implicit inclusion of aerosols in a microphysics parameterization scheme in Weather Research and Forecasting (WRF) - Advanced Research WRF (WRF-ARW) model has on cloud dynamics and microphysics. The testbed selected for this study is a severe mesoscale convective system with supercells that struck west and central parts of Serbia in the afternoon of July 21, 2014. Numerical products of two model runs, i.e. one with aerosols explicitly (WRF-AE) included and another with aerosols implicitly (WRF-AI) assumed, are compared against precipitation measurements from surface network of rain gauges, as well as against radar and satellite observations. The WRF-AE model accurately captured the transportation of dust from the north Africa over the Mediterranean and to the Balkan region. On smaller scales, both models displaced the locations of clouds situated above west and central Serbia towards southeast and under-predicted the maximum values of composite radar reflectivity. Similar to satellite images, WRF-AE shows the mesoscale convective system as a merged cluster of cumulonimbus clouds. Both models over-predicted the precipitation amounts; WRF-AE over-predictions are particularly pronounced in the zones of light rain, while WRF-AI gave larger outliers. Unlike WRF-AI, the WRF-AE approach enables the modelling of time evolution and influx of aerosols into the cloud which could be of practical importance in weather forecasting and weather modification. Several likely causes for discrepancies between models and observations are discussed and prospects for further research in this field are outlined.

  2. A mechanistic soil biogeochemistry model with explicit representation of microbial and macrofaunal activities and nutrient cycles

    Science.gov (United States)

    Fatichi, Simone; Manzoni, Stefano; Or, Dani; Paschalis, Athanasios

    2016-04-01

    The potential of a given ecosystem to store and release carbon is inherently linked to soil biogeochemical processes. These processes are deeply connected to the water, energy, and vegetation dynamics above and belowground. Recently, it has been advocated that a mechanistic representation of soil biogeochemistry require: (i) partitioning of soil organic carbon (SOC) pools according to their functional role; (ii) an explicit representation of microbial dynamics; (iii) coupling of carbon and nutrient cycles. While some of these components have been introduced in specialized models, they have been rarely implemented in terrestrial biosphere models and tested in real cases. In this study, we combine a new soil biogeochemistry model with an existing model of land-surface hydrology and vegetation dynamics (T&C). Specifically the soil biogeochemistry component explicitly separates different litter pools and distinguishes SOC in particulate, dissolved and mineral associated fractions. Extracellular enzymes and microbial pools are explicitly represented differentiating the functional roles of bacteria, saprotrophic and mycorrhizal fungi. Microbial activity depends on temperature, soil moisture and litter or SOC stoichiometry. The activity of macrofauna is also modeled. Nutrient dynamics include the cycles of nitrogen, phosphorous and potassium. The model accounts for feedbacks between nutrient limitations and plant growth as well as for plant stoichiometric flexibility. In turn, litter input is a function of the simulated vegetation dynamics. Root exudation and export to mycorrhiza are computed based on a nutrient uptake cost function. The combined model is tested to reproduce respiration dynamics and nitrogen cycle in few sites where data were available to test plausibility of results across a range of different metrics. For instance in a Swiss grassland ecosystem, fine root, bacteria, fungal and macrofaunal respiration account for 40%, 23%, 33% and 4% of total belowground

  3. Effect of Vapor Pressure Scheme on Multiday Evolution of SOA in an Explicit Model

    Science.gov (United States)

    Lee-Taylor, J.; Madronich, S.; Aumont, B.; Camredon, M.; Emmons, L. K.; Tyndall, G. S.; Valorso, R.

    2011-12-01

    Recent modeling of the evolution of Secondary Organic Aerosol (SOA) has led to the critically important prediction that SOA mass continues to increase for several days after emission of primary pollutants. This growth of organic aerosol in dispersing plumes originating from urban point sources has direct implications for regional aerosol radiative forcing. We investigate the robustness of predicted SOA mass growth downwind of Mexico City in the model GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere), by assessing its sensitivity to the choice of vapor pressure prediction scheme. We also explore the implications for multi-day SOA mass growth of glassification / solidification of SOA constituents during aging. Finally we use output from the MOZART-4 chemical transport model to evaluate our results in the regional and global context.

  4. Interaction of the model alkyltrimethylammonium ions with alkali halide salts: an explicit water molecular dynamics study

    Directory of Open Access Journals (Sweden)

    M. Druchok

    2013-01-01

    Full Text Available We present an explicit water molecular dynamics simulation of dilute solutions of model alkyltrimethylammonium surfactant ions (number of methylene groups in the tail is 3, 5, 8, 10, and 12 in mixture with NaF, NaCl, NaBr, and NaI salts, respectively. The SPC/E model is used to describe water molecules. Results of the simulation at 298 K are presented in form of the radial distribution functions between nitrogen and carbon atoms of CH2 groups on the alkyltrimethylammonium ion, and the counterion species in the solution. The running coordination numbers between carbon atoms of surfactants and counterions are also calculated. We show that I- counterion exhibits the highest, and F- the lowest affinity to "bind" to the model surfactants. The results are discussed in view of the available experimental and simulation data for this and similar solutions.

  5. Explicitly modelled deep-time tidal dissipation and its implication for Lunar history

    Science.gov (United States)

    Green, J. A. M.; Huber, M.; Waltham, D.; Buzan, J.; Wells, M.

    2017-03-01

    Dissipation of tidal energy causes the Moon to recede from the Earth. The currently measured rate of recession implies that the age of the Lunar orbit is 1500 My old, but the Moon is known to be 4500 My old. Consequently, it has been proposed that tidal energy dissipation was weaker in the Earth's past, but explicit numerical calculations are missing for such long time intervals. Here, for the first time, numerical tidal model simulations linked to climate model output are conducted for a range of paleogeographic configurations over the last 252 My. We find that the present is a poor guide to the past in terms of tidal dissipation: the total dissipation rates for most of the past 252 My were far below present levels. This allows us to quantify the reduced tidal dissipation rates over the most resent fraction of lunar history, and the lower dissipation allows refinement of orbitally-derived age models by inserting a complete additional precession cycle.

  6. Exploration of the seasonal variation of organic aerosol composition using an explicit modeling approach

    Science.gov (United States)

    Ouzebidour, Farida; Camredon, Marie; Stéphanie La, Yuyi; Madronich, Sasha; Taylor, Julia Lee; Hodzic, Alma; Beekmann, Matthias; Siour, Guillaume; Aumont, Bernard

    2014-05-01

    Organic compounds account for a major fraction of fine aerosols in the atmosphere. This organic fraction is dominated by secondary organic aerosol (SOA). Processes leading to SOA formation are however still uncertain and SOA composition is far from being fully characterized. The goals of this study are to evaluate our current understanding of SOA formation and explore its composition. For this purpose, a box-model that describes explicitly processes involved in SOA formation has been developed. This model includes the emission of 183 gaseous and particulate organic compounds. The oxidation of these emitted organic compounds is described using the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A). Gas/particle partitioning has been implemented considering an ideal homogeneous condensed phase. The generated chemical scheme contains 500,000 species and the gas/particle partitioning is performed for 90,000 of them. Simulations have been performed for summer and winter scenarios representative of continental and urban conditions. NOx and ozone simulated concentrations reproduce the expected winter and summer diurnal evolutions. The predicted organic aerosol composition is a mixture of primary and secondary organic aerosols during the winter and is largely dominated by SOA during the summer.

  7. Penggunaan Model Pembelajaran Explicit Instruction Dengan Trainer PLC Untuk Meningkatkan Prestasi Belajar Merakit Sistem PLC

    Directory of Open Access Journals (Sweden)

    Suroto Suroto

    2015-11-01

    Full Text Available The purpose of the research was to implement the Explicit Instruction Learning Model using trainer PLC media to improve the students’ learning achievement and motivation in assembling PLC system subject. The research methodology used classroom action research with XII TOI students of SMK Negeri 2 Depok as the sample. The research instruments used were formative tests and practice job sheets. The result of research showed that the average formative test in cycle I was 76,10 ; in cycle II was 80,32 and in cycle III was 83,77. Based on the findings, it means that the students ‘scores were higher than the provided minimum requirement score after using the Explicit Instruction Model using trainer PLC media in cycle I,II and III. The students’ learning motivation in cycle I, II and III were 67, 82 ,and 85 respectively. It can be concluded that the students’ learning motivation was improving from (≤ 75 to ( ≥ 75 at the second and third cycles.

  8. Ophiucus: RDF-based visualization tool for health simulation models.

    Science.gov (United States)

    Sutcliffe, Andrew; Okhmatovskaia, Anya; Shaban-Nejad, Arash; Buckeridge, David

    2012-01-01

    Simulation modeling of population health is becoming increasingly popular for epidemiology research and public health policy-making. However, the acceptability of population health simulation models is inhibited by their complexity and the lack of established standards to describe these models. To address this issue, we propose Ophiuchus - an RDF (Resource Description Framework: http://www.w3.org/RDF/)-based visualization tool for generating interactive 2D diagrams of population health simulation models, which describe these models in an explicit and formal manner. We present the results of a preliminary system assessment and discuss current limitations of the system.

  9. Design and application of a technologically explicit hybrid energy-economy policy model with micro and macro economic dynamics

    Science.gov (United States)

    Bataille, Christopher G. F.

    2005-11-01

    autonomous energy efficiency indices (AEEI) from the model, parameters that could be used in long-run computable general equilibrium (CGE) analysis. The thesis concludes with a summary of the strengths and weakness of the new model as a policy tool, a work plan for its further improvement, and a discussion of the general potential for technologically explicit general equilibrium modelling.

  10. Impact of mosquito gene drive on malaria elimination in a computational model with explicit spatial and temporal dynamics

    Science.gov (United States)

    Eckhoff, Philip A.; Wenger, Edward A.; Godfray, H. Charles J.; Burt, Austin

    2017-01-01

    The renewed effort to eliminate malaria and permanently remove its tremendous burden highlights questions of what combination of tools would be sufficient in various settings and what new tools need to be developed. Gene drive mosquitoes constitute a promising set of tools, with multiple different possible approaches including population replacement with introduced genes limiting malaria transmission, driving-Y chromosomes to collapse a mosquito population, and gene drive disrupting a fertility gene and thereby achieving population suppression or collapse. Each of these approaches has had recent success and advances under laboratory conditions, raising the urgency for understanding how each could be deployed in the real world and the potential impacts of each. New analyses are needed as existing models of gene drive primarily focus on nonseasonal or nonspatial dynamics. We use a mechanistic, spatially explicit, stochastic, individual-based mathematical model to simulate each gene drive approach in a variety of sub-Saharan African settings. Each approach exhibits a broad region of gene construct parameter space with successful elimination of malaria transmission due to the targeted vector species. The introduction of realistic seasonality in vector population dynamics facilitates gene drive success compared with nonseasonal analyses. Spatial simulations illustrate constraints on release timing, frequency, and spatial density in the most challenging settings for construct success. Within its parameter space for success, each gene drive approach provides a tool for malaria elimination unlike anything presently available. Provided potential barriers to success are surmounted, each achieves high efficacy at reducing transmission potential and lower delivery requirements in logistically challenged settings. PMID:28028208

  11. Explicit Solution of Reinsurance-Investment Problem for an Insurer with Dynamic Income under Vasicek Model

    Directory of Open Access Journals (Sweden)

    De-Lei Sheng

    2016-01-01

    Full Text Available Unlike traditionally used reserves models, this paper focuses on a reserve process with dynamic income to study the reinsurance-investment problem for an insurer under Vasicek stochastic interest rate model. The insurer’s dynamic income is given by the remainder after a dynamic reward budget being subtracted from the insurer’s net premium which is calculated according to expected premium principle. Applying stochastic control technique, a Hamilton-Jacobi-Bellman equation is established and the explicit solution is obtained under the objective of maximizing the insurer’s power utility of terminal wealth. Some economic interpretations of the obtained results are explained in detail. In addition, numerical analysis and several graphics are given to illustrate our results more meticulous.

  12. Nano-colloid electrophoretic transport: Fully explicit modelling via dissipative particle dynamics

    Science.gov (United States)

    Hassanzadeh Afrouzi, Hamid; Farhadi, Mousa; Sedighi, Kurosh; Moshfegh, Abouzar

    2018-02-01

    In present study, a novel fully explicit approach using dissipative particle dynamics (DPD) method is introduced for modelling electrophoretic transport of nano-colloids in an electrolyte solution. Slater type charge smearing function included in 3D Ewald summation method is employed to treat electrostatic interaction. Moreover, capability of different thermostats are challenged to control the system temperature and study the dynamic response of colloidal electrophoretic mobility under practical ranges of external electric field in nano scale application (0.072 600 in DPD units regardless of electric field intensity. Nosé-Hoover-Lowe-Andersen and Lowe-Andersen thermostats are found to function more effectively under high electric fields (E > 0.145 [ v / nm ]) while thermal equilibrium is maintained. Reasonable agreements are achieved by benchmarking the radial distribution function with available electrolyte structure modellings, as well as comparing reduced mobility against conventional Smoluchowski and Hückel theories, and numerical solution of Poisson-Boltzmann equation.

  13. Charged patchy particle models in explicit salt: Ion distributions, electrostatic potentials, and effective interactions.

    Science.gov (United States)

    Yigit, Cemil; Heyda, Jan; Dzubiella, Joachim

    2015-08-14

    We introduce a set of charged patchy particle models (CPPMs) in order to systematically study the influence of electrostatic charge patchiness and multipolarity on macromolecular interactions by means of implicit-solvent, explicit-ion Langevin dynamics simulations employing the Gromacs software. We consider well-defined zero-, one-, and two-patched spherical globules each of the same net charge and (nanometer) size which are composed of discrete atoms. The studied mono- and multipole moments of the CPPMs are comparable to those of globular proteins with similar size. We first characterize ion distributions and electrostatic potentials around a single CPPM. Although angle-resolved radial distribution functions reveal the expected local accumulation and depletion of counter- and co-ions around the patches, respectively, the orientation-averaged electrostatic potential shows only a small variation among the various CPPMs due to space charge cancellations. Furthermore, we study the orientation-averaged potential of mean force (PMF), the number of accumulated ions on the patches, as well as the CPPM orientations along the center-to-center distance of a pair of CPPMs. We compare the PMFs to the classical Derjaguin-Verwey-Landau-Overbeek theory and previously introduced orientation-averaged Debye-Hückel pair potentials including dipolar interactions. Our simulations confirm the adequacy of the theories in their respective regimes of validity, while low salt concentrations and large multipolar interactions remain a challenge for tractable theoretical descriptions.

  14. Charged patchy particle models in explicit salt: Ion distributions, electrostatic potentials, and effective interactions

    Energy Technology Data Exchange (ETDEWEB)

    Yigit, Cemil; Dzubiella, Joachim, E-mail: joachim.dzubiella@helmholtz-berlin.de [Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, 14109 Berlin (Germany); Helmholtz Virtual Institute “Multifunctional Biomaterials for Medicine,” 14513 Teltow (Germany); Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin (Germany); Heyda, Jan [Department of Physical Chemistry, University of Chemistry and Technology, Prague, 166 28 Praha 6 (Czech Republic)

    2015-08-14

    We introduce a set of charged patchy particle models (CPPMs) in order to systematically study the influence of electrostatic charge patchiness and multipolarity on macromolecular interactions by means of implicit-solvent, explicit-ion Langevin dynamics simulations employing the Gromacs software. We consider well-defined zero-, one-, and two-patched spherical globules each of the same net charge and (nanometer) size which are composed of discrete atoms. The studied mono- and multipole moments of the CPPMs are comparable to those of globular proteins with similar size. We first characterize ion distributions and electrostatic potentials around a single CPPM. Although angle-resolved radial distribution functions reveal the expected local accumulation and depletion of counter- and co-ions around the patches, respectively, the orientation-averaged electrostatic potential shows only a small variation among the various CPPMs due to space charge cancellations. Furthermore, we study the orientation-averaged potential of mean force (PMF), the number of accumulated ions on the patches, as well as the CPPM orientations along the center-to-center distance of a pair of CPPMs. We compare the PMFs to the classical Derjaguin-Verwey-Landau-Overbeek theory and previously introduced orientation-averaged Debye-Hückel pair potentials including dipolar interactions. Our simulations confirm the adequacy of the theories in their respective regimes of validity, while low salt concentrations and large multipolar interactions remain a challenge for tractable theoretical descriptions.

  15. Spatial-explicit modeling of social vulnerability to malaria in East Africa.

    Science.gov (United States)

    Kienberger, Stefan; Hagenlocher, Michael

    2014-08-15

    Despite efforts in eradication and control, malaria remains a global challenge, particularly affecting vulnerable groups. Despite the recession in malaria cases, previously malaria free areas are increasingly confronted with epidemics as a result of changing environmental and socioeconomic conditions. Next to modeling transmission intensities and probabilities, integrated spatial methods targeting the complex interplay of factors that contribute to social vulnerability are required to effectively reduce malaria burden. We propose an integrative method for mapping relative levels of social vulnerability in a spatially explicit manner to support the identification of intervention measures. Based on a literature review, a holistic risk and vulnerability framework has been developed to guide the assessment of social vulnerability to water-related vector-borne diseases (VBDs) in the context of changing environmental and societal conditions. Building on the framework, this paper applies spatially explicit modeling for delineating homogeneous regions of social vulnerability to malaria in eastern Africa, while taking into account expert knowledge for weighting the single vulnerability indicators. To assess the influence of the selected indicators on the final index a local sensitivity analysis is carried out. Results indicate that high levels of malaria vulnerability are concentrated in the highlands, where immunity within the population is currently low. Additionally, regions with a lack of access to education and health services aggravate vulnerability. Lower values can be found in regions with relatively low poverty, low population pressure, low conflict density and reduced contributions from the biological susceptibility domain. Overall, the factors characterizing vulnerability vary spatially in the region. The vulnerability index reveals a high level of robustness in regard to the final choice of input datasets, with the exception of the immunity indicator which has a

  16. Comparison of Explicitly Simulated and Downscaled Tropical Cyclone Activity in a High-Resolution Global Climate Model

    Directory of Open Access Journals (Sweden)

    Hirofumi Tomita

    2010-01-01

    Full Text Available The response of tropical cyclone activity to climate change is a matter of great inherent interest and practical importance. Most current global climate models are not, however, capable of adequately resolving tropical cyclones; this has led to the development of downscaling techniques designed to infer tropical cyclone activity from the large-scale fields produced by climate models. Here we compare the statistics of tropical cyclones simulated explicitly in a very high resolution (~14 km grid mesh global climate model to the results of one such downscaling technique driven by the same global model. This is done for a simulation of the current climate and also for a simulation of a climate warmed by the addition of carbon dioxide. The explicitly simulated and downscaled storms are similarly distributed in space, but the intensity distribution of the downscaled events has a somewhat longer high-intensity tail, owing to the higher resolution of the downscaling model. Both explicitly simulated and downscaled events show large increases in the frequency of events at the high-intensity ends of their respective intensity distributions, but the downscaled storms also show increases in low-intensity events, whereas the explicitly simulated weaker events decline in number. On the regional scale, there are large differences in the responses of the explicitly simulated and downscaled events to global warming. In particular, the power dissipation of downscaled events shows a 175% increase in the Atlantic, while the power dissipation of explicitly simulated events declines there.

  17. An atomic charge model for graphene oxide for exploring its bioadhesive properties in explicit water

    Energy Technology Data Exchange (ETDEWEB)

    Stauffer, D.; Dragneva, N.; Floriano, W. B.; Rubel, O. [Thunder Bay Regional Research Institute, 290 Munro St, Thunder Bay, Ontario P7B 6V4 (Canada); Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7A 7T1 (Canada); Mawhinney, R. C. [Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7A 7T1 (Canada); Fanchini, G. [Physics and Astronomy, University of Western Ontario, 1151 Richmond St, London, Ontario N6A 3K7 (Canada); French, S. [University of Calgary, South Health Campus, 4448 Front St. SE, Calgary, Alberta T3M 1M4 (Canada)

    2014-07-28

    Graphene Oxide (GO) has been shown to exhibit properties that are useful in applications such as biomedical imaging, biological sensors, and drug delivery. The binding properties of biomolecules at the surface of GO can provide insight into the potential biocompatibility of GO. Here we assess the intrinsic affinity of amino acids to GO by simulating their adsorption onto a GO surface. The simulation is done using Amber03 force-field molecular dynamics in explicit water. The emphasis is placed on developing an atomic charge model for GO. The adsorption energies are computed using atomic charges obtained from an ab initio electrostatic potential based method. The charges reported here are suitable for simulating peptide adsorption to GO.

  18. An explicit closed-form analytical solution for European options under the CGMY model

    Science.gov (United States)

    Chen, Wenting; Du, Meiyu; Xu, Xiang

    2017-01-01

    In this paper, we consider the analytical pricing of European path-independent options under the CGMY model, which is a particular type of pure jump Le´vy process, and agrees well with many observed properties of the real market data by allowing the diffusions and jumps to have both finite and infinite activity and variation. It is shown that, under this model, the option price is governed by a fractional partial differential equation (FPDE) with both the left-side and right-side spatial-fractional derivatives. In comparison to derivatives of integer order, fractional derivatives at a point not only involve properties of the function at that particular point, but also the information of the function in a certain subset of the entire domain of definition. This ;globalness; of the fractional derivatives has added an additional degree of difficulty when either analytical methods or numerical solutions are attempted. Albeit difficult, we still have managed to derive an explicit closed-form analytical solution for European options under the CGMY model. Based on our solution, the asymptotic behaviors of the option price and the put-call parity under the CGMY model are further discussed. Practically, a reliable numerical evaluation technique for the current formula is proposed. With the numerical results, some analyses of impacts of four key parameters of the CGMY model on European option prices are also provided.

  19. Spatially-explicit modelling of nutrient loading to the landscape in the Great Lakes Basin

    Science.gov (United States)

    Hamlin, Q. F.; Kendall, A. D.; Martin, S. L.; Whitenack, H. D.; Hyndman, D. W.

    2016-12-01

    Loading of nitrogen and phosphorus to the landscape has resulted in dangerous algal blooms, contaminated drinking water, and decreased biodiversity. Here, we developed a GIS model to estimate spatially explicit nutrient loading across the Great Lakes Basin. The model expands on previous work in the lower peninsula of Michigan by Luscz et al. (2015). Inputs to the model include point source loads to streams along with five non-point source landscape loads: atmospheric deposition, chemical agricultural fertilizer, chemical non-agricultural fertilizer, manure application, and septic tanks. Scaling up from Michigan to the eight U.S. states and two Canadian provinces in the Great Lakes Basin provided unique challenges. In the case of the septic tank inputs, we compiled a multistate database of drinking water wells for use in an automated Python script to delineate wastewater treatment plant service areas and to estimate placement of septic tanks appropriately within the landscape. Using a model with individual nutrient inputs showed that even within a single land use class, there is high variability in loading rates. This variability suggests that simply prescribing loading estimates based on land use class is insufficient. Modelling high resolution and source specific landscape nutrient loading will be valuable to target strategies to decrease excessive anthropogenic nutrient loading in the Great Lakes Basin.

  20. A Risk Explicit Interval Linear Programming Model for Uncertainty-Based Environmental Economic Optimization in the Lake Fuxian Watershed, China

    Directory of Open Access Journals (Sweden)

    Xiaoling Zhang

    2013-01-01

    Full Text Available The conflict of water environment protection and economic development has brought severe water pollution and restricted the sustainable development in the watershed. A risk explicit interval linear programming (REILP method was used to solve integrated watershed environmental-economic optimization problem. Interval linear programming (ILP and REILP models for uncertainty-based environmental economic optimization at the watershed scale were developed for the management of Lake Fuxian watershed, China. Scenario analysis was introduced into model solution process to ensure the practicality and operability of optimization schemes. Decision makers’ preferences for risk levels can be expressed through inputting different discrete aspiration level values into the REILP model in three periods under two scenarios. Through balancing the optimal system returns and corresponding system risks, decision makers can develop an efficient industrial restructuring scheme based directly on the window of “low risk and high return efficiency” in the trade-off curve. The representative schemes at the turning points of two scenarios were interpreted and compared to identify a preferable planning alternative, which has the relatively low risks and nearly maximum benefits. This study provides new insights and proposes a tool, which was REILP, for decision makers to develop an effectively environmental economic optimization scheme in integrated watershed management.

  1. A risk explicit interval linear programming model for uncertainty-based environmental economic optimization in the Lake Fuxian watershed, China.

    Science.gov (United States)

    Zhang, Xiaoling; Huang, Kai; Zou, Rui; Liu, Yong; Yu, Yajuan

    2013-01-01

    The conflict of water environment protection and economic development has brought severe water pollution and restricted the sustainable development in the watershed. A risk explicit interval linear programming (REILP) method was used to solve integrated watershed environmental-economic optimization problem. Interval linear programming (ILP) and REILP models for uncertainty-based environmental economic optimization at the watershed scale were developed for the management of Lake Fuxian watershed, China. Scenario analysis was introduced into model solution process to ensure the practicality and operability of optimization schemes. Decision makers' preferences for risk levels can be expressed through inputting different discrete aspiration level values into the REILP model in three periods under two scenarios. Through balancing the optimal system returns and corresponding system risks, decision makers can develop an efficient industrial restructuring scheme based directly on the window of "low risk and high return efficiency" in the trade-off curve. The representative schemes at the turning points of two scenarios were interpreted and compared to identify a preferable planning alternative, which has the relatively low risks and nearly maximum benefits. This study provides new insights and proposes a tool, which was REILP, for decision makers to develop an effectively environmental economic optimization scheme in integrated watershed management.

  2. Global distribution and sources of dissolved inorganic nitrogen export to the coastal zone: Results from a spatially explicit, global model

    NARCIS (Netherlands)

    Dumont, E.L.; Harrison, J.A.; Kroeze, C.; Bakker, E.J.; Seitzinger, S.P.

    2005-01-01

    Here we describe, test, and apply a spatially explicit, global model for predicting dissolved inorganic nitrogen (DIN) export by rivers to coastal waters (NEWS-DIN). NEWS-DIN was developed as part of an internally consistent suite of global nutrient export models. Modeled and measured DIN export

  3. Reparametrized E3B (Explicit Three-Body) Water Model Using the TIP4P/2005 Model as a Reference.

    Science.gov (United States)

    Tainter, Craig J; Shi, Liang; Skinner, James L

    2015-05-12

    In this study, we present the third version of a water model that explicitly includes three-body interactions. The major difference between this version and the previous two is in the two-body water model we use as a reference potential; here we use the TIP4P/2005 model (previous versions used the TIP4P water model). We alter four parameters from our previous version of the model by fitting to the diffusion coefficient of the ambient liquid, the liquid and ice densities, and the melting point. We evaluate the performance of this version by calculating many other microscopic and thermodynamic static and dynamic properties as a function of temperature and near the critical point and comparing to experiment, the TIP4P/2005 model and the previous version of our three-body model.

  4. Hydroclimatology of Dual-Peak Annual Cholera Incidence: Insights from a Spatially Explicit Model

    Science.gov (United States)

    Bertuzzo, E.; Mari, L.; Righetto, L.; Gatto, M.; Casagrandi, R.; Rodriguez-Iturbe, I.; Rinaldo, A.

    2012-12-01

    Cholera incidence in some regions of the Indian subcontinent may exhibit two annual peaks although the main environmental drivers that have been linked to the disease (e.g. sea surface temperature, zooplankton abundance, river discharge) peak once per year during the summer. An empirical hydroclimatological explanation relating cholera transmission to river flows and to the disease spatial spreading has been recently proposed. We specifically support and substantiate mechanistically such hypothesis by means of a spatially explicit model of cholera transmission. Our framework directly accounts for the role of the river network in transporting and redistributing cholera bacteria among human communities as well as for spatial and temporal annual fluctuations of precipitation and river flows. To single out the single out the hydroclimatologic controls on the prevalence patterns in a non-specific geographical context, we first apply the model to Optimal Channel Networks as a general model of hydrological networks. Moreover, we impose a uniform distribution of population. The model is forced by seasonal environmental drivers, namely precipitation, temperature and chlorophyll concentration in the coastal environment, a proxy for Vibrio cholerae concentration. Our results show that these drivers may suffice to generate dual-peak cholera prevalence patterns for proper combinations of timescales involved in pathogen transport, hydrologic variability and disease unfolding. The model explains the possible occurrence of spatial patterns of cholera incidence characterized by a spring peak confined to coastal areas and a fall peak involving inland regions. We then proceed applying the model to the specific settings of Bay of Bengal accounting for the actual river networks (derived from digital terrain map manipulations), the proper distribution of population (estimated from downscaling of census data based on remotely sensed features) and precipitation patterns. Overall our

  5. Life histories and Cope's rule from an explicit resource-consumer model based on metabolic theory.

    Science.gov (United States)

    Song, Yixian; Scheu, Stefan; Drossel, Barbara

    2012-10-07

    We explore the consequences of metabolic theory for life histories and life history evolution. We use a mathematical model for an iteroparous species and its resources, taking into account the allometric scaling of consumption, metabolism, and mortality with consumer body mass. Mortality is assumed to be density-dependent, and the dynamics of resources are modeled explicitly. By evaluating life history features in equilibrium populations, we find that in populations that use more or faster growing resources the individuals have a shorter lifespan and a higher mortality, and that individuals in populations with a larger adult body mass have a longer lifespan, a larger number of offspring per female, and a higher biomass density. When we allow the adult body mass to evolve, it increases in time without limits. When we allow the offspring body mass to evolve independently from adult body mass, it becomes smaller. However, when we take into account that larger individuals have larger offspring, both body masses evolve to larger values. These trends result from the allometric scaling of mortality and can be kept in limits by trade-offs other than those included in our model. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Explicit Nonlinear Model Predictive Control for a Saucer-Shaped Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Zhihui Xing

    2013-01-01

    Full Text Available A lifting body unmanned aerial vehicle (UAV generates lift by its body and shows many significant advantages due to the particular shape, such as huge loading space, small wetted area, high-strength fuselage structure, and large lifting area. However, designing the control law for a lifting body UAV is quite challenging because it has strong nonlinearity and coupling, and usually lacks it rudders. In this paper, an explicit nonlinear model predictive control (ENMPC strategy is employed to design a control law for a saucer-shaped UAV which can be adequately modeled with a rigid 6-degrees-of-freedom (DOF representation. In the ENMPC, control signal is calculated by approximation of the tracking error in the receding horizon by its Taylor-series expansion to any specified order. It enhances the advantages of the nonlinear model predictive control and eliminates the time-consuming online optimization. The simulation results show that ENMPC is a propriety strategy for controlling lifting body UAVs and can compensate the insufficient control surface area.

  7. Graph theory as a proxy for spatially explicit population models in conservation planning.

    Science.gov (United States)

    Minor, Emily S; Urban, Dean L

    2007-09-01

    Spatially explicit population models (SEPMs) are often considered the best way to predict and manage species distributions in spatially heterogeneous landscapes. However, they are computationally intensive and require extensive knowledge of species' biology and behavior, limiting their application in many cases. An alternative to SEPMs is graph theory, which has minimal data requirements and efficient algorithms. Although only recently introduced to landscape ecology, graph theory is well suited to ecological applications concerned with connectivity or movement. This paper compares the performance of graph theory to a SEPM in selecting important habitat patches for Wood Thrush (Hylocichla mustelina) conservation. We use both models to identify habitat patches that act as population sources and persistent patches and also use graph theory to identify patches that act as stepping stones for dispersal. Correlations of patch rankings were very high between the two models. In addition, graph theory offers the ability to identify patches that are very important to habitat connectivity and thus long-term population persistence across the landscape. We show that graph theory makes very similar predictions in most cases and in other cases offers insight not available from the SEPM, and we conclude that graph theory is a suitable and possibly preferable alternative to SEPMs for species conservation in heterogeneous landscapes.

  8. A novel explicit approach to model bromide and pesticide transport in connected soil structures

    Directory of Open Access Journals (Sweden)

    J. Klaus

    2011-07-01

    Full Text Available The present study tests whether an explicit treatment of worm burrows and tile drains as connected structures is feasible for simulating water flow, bromide and pesticide transport in structured heterogeneous soils at hillslope scale. The essence is to represent worm burrows as morphologically connected paths of low flow resistance in a hillslope model. A recent Monte Carlo study (Klaus and Zehe, 2010, Hydrological Processes, 24, p. 1595–1609 revealed that this approach allowed successful reproduction of tile drain event discharge recorded during an irrigation experiment at a tile drained field site. However, several "hillslope architectures" that were all consistent with the available extensive data base allowed a good reproduction of tile drain flow response. Our second objective was thus to find out whether this "equifinality" in spatial model setups may be reduced when including bromide tracer data in the model falsification process. We thus simulated transport of bromide for the 13 spatial model setups that performed best with respect to reproduce tile drain event discharge, without any further calibration. All model setups allowed a very good prediction of the temporal dynamics of cumulated bromide leaching into the tile drain, while only four of them matched the accumulated water balance and accumulated bromide loss into the tile drain. The number of behavioural model architectures could thus be reduced to four. One of those setups was used for simulating transport of Isoproturon, using different parameter combinations to characterise adsorption according to the Footprint data base. Simulations could, however, only reproduce the observed leaching behaviour, when we allowed for retardation coefficients that were very close to one.

  9. Direct adaptive feedforward compensation of narrowband disturbances without explicit identification of the secondary path model

    Science.gov (United States)

    Zech, Philipp; Lato, Victorio; Rinderknecht, Stephan

    2017-08-01

    The effectiveness of common algorithms for feedforward compensation of narrowband disturbance depends mainly on the model quality. To avoid this dependency several direct adaptive control algorithms without explicitly identified secondary path models have been developed over the last years. However an overview of their properties and a comparison of their performances in a standardized benchmark is still lacking. In this paper the three most promising algorithms are modified for narrowband feedforward vibration control for the use in rotating machinery. As in this application the reference signal is generated using the frequency measurement from a speed sensor it can be assumed that there is no coupling between reference measurement and the secondary path. First the algorithms are tested in simulation, then they are implemented on a test rig for active vibration control of unbalance induced rotor vibration. In simulation as well as for the test rig the performances of the algorithms are compared to each other. Advantages and drawbacks of the algorithms are discussed and practical instructions for implementation are given. The work is intended to serve as starting point and motivation for future research in this field of study.

  10. Explicit modelling of SOA formation from α-pinene photooxidation: sensitivity to vapour pressure estimation

    Directory of Open Access Journals (Sweden)

    R. Valorso

    2011-07-01

    Full Text Available The sensitivity of the formation of secondary organic aerosol (SOA to the estimated vapour pressures of the condensable oxidation products is explored. A highly detailed reaction scheme was generated for α-pinene photooxidation using the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A. Vapour pressures (Pvap were estimated with three commonly used structure activity relationships. The values of Pvap were compared for the set of secondary species generated by GECKO-A to describe α-pinene oxidation. Discrepancies in the predicted vapour pressures were found to increase with the number of functional groups borne by the species. For semi-volatile organic compounds (i.e. organic species of interest for SOA formation, differences in the predicted Pvap range between a factor of 5 to 200 on average. The simulated SOA concentrations were compared to SOA observations in the Caltech chamber during three experiments performed under a range of NOx conditions. While the model captures the qualitative features of SOA formation for the chamber experiments, SOA concentrations are systematically overestimated. For the conditions simulated, the modelled SOA speciation appears to be rather insensitive to the Pvap estimation method.

  11. A genetically explicit model of speciation by sensory drive within a continuous population in aquatic environments

    Directory of Open Access Journals (Sweden)

    Seehausen Ole

    2007-06-01

    Full Text Available Abstract Background The sensory drive hypothesis predicts that divergent sensory adaptation in different habitats may lead to premating isolation upon secondary contact of populations. Speciation by sensory drive has traditionally been treated as a special case of speciation as a byproduct of adaptation to divergent environments in geographically isolated populations. However, if habitats are heterogeneous, local adaptation in the sensory systems may cause the emergence of reproductively isolated species from a single unstructured population. In polychromatic fishes, visual sensitivity might become adapted to local ambient light regimes and the sensitivity might influence female preferences for male nuptial color. In this paper, we investigate the possibility of speciation by sensory drive as a byproduct of divergent visual adaptation within a single initially unstructured population. We use models based on explicit genetic mechanisms for color vision and nuptial coloration. Results We show that in simulations in which the adaptive evolution of visual pigments and color perception are explicitly modeled, sensory drive can promote speciation along a short selection gradient within a continuous habitat and population. We assumed that color perception evolves to adapt to the modal light environment that individuals experience and that females prefer to mate with males whose nuptial color they are most sensitive to. In our simulations color perception depends on the absorption spectra of an individual's visual pigments. Speciation occurred most frequently when the steepness of the environmental light gradient was intermediate and dispersal distance of offspring was relatively small. In addition, our results predict that mutations that cause large shifts in the wavelength of peak absorption promote speciation, whereas we did not observe speciation when peak absorption evolved by stepwise mutations with small effect. Conclusion The results suggest

  12. Human Mobility Patterns and Cholera Epidemics: a Spatially Explicit Modeling Approach

    Science.gov (United States)

    Mari, L.; Bertuzzo, E.; Righetto, L.; Casagrandi, R.; Gatto, M.; Rodriguez-Iturbe, I.; Rinaldo, A.

    2010-12-01

    Cholera is an acute enteric disease caused by the ingestion of water or food contaminated by the bacterium Vibrio cholerae. Although most infected individuals do not develop severe symptoms, their stool may contain huge quantities of V.~cholerae cells. Therefore, while traveling or commuting, asymptomatic carriers can be responsible for the long-range dissemination of the disease. As a consequence, human mobility is an alternative and efficient driver for the spread of cholera, whose primary propagation pathway is hydrological transport through river networks. We present a multi-layer network model that accounts for the interplay between epidemiological dynamics, hydrological transport and long-distance dissemination of V.~cholerae due to human movement. In particular, building on top of state-of-the-art spatially explicit models for cholera spread through surface waters, we describe human movement and its effects on the propagation of the disease by means of a gravity-model approach borrowed from transportation theory. Gravity-like contact processes have been widely used in epidemiology, because they can satisfactorily depict human movement when data on actual mobility patterns are not available. We test our model against epidemiological data recorded during the cholera outbreak occurred in the KwaZulu-Natal province of South Africa during years 2000--2001. We show that human mobility does actually play an important role in the formation of the spatiotemporal patterns of cholera epidemics. In particular, long-range human movement may determine inter-catchment dissemination of V.~cholerae cells, thus in turn explaining the emergence of epidemic patterns that cannot be produced by hydrological transport alone. We also show that particular attention has to be devoted to study how heterogeneously distributed drinking water supplies and sanitation conditions may affect cholera transmission.

  13. Algebraic Model for Agent Explicit Knowledge in Multi-agent Systems

    OpenAIRE

    Sabri, Khair Eddin; Khedri, Ridha; Jaskolka, Jason

    2009-01-01

    In this chapter, we present a structure to specify agent explicit knowledge based on information algebra. We define in the context of agent knowledge the combining, marginalizing, and labelling operators. Also, we define remove and frame substitution operator. These operators are all what is needed to express operations on agent explicit knowledge. We also define a set of frames to be associated with information. Then, we prove that our structure is an information algebra which links our work...

  14. Resolution and Energy Dissipation Characteristics of Implicit LES and Explicit Filtering Models for Compressible Turbulence

    Directory of Open Access Journals (Sweden)

    Romit Maulik

    2017-04-01

    Full Text Available Solving two-dimensional compressible turbulence problems up to a resolution of 16, 384^2, this paper investigates the characteristics of two promising computational approaches: (i an implicit or numerical large eddy simulation (ILES framework using an upwind-biased fifth-order weighted essentially non-oscillatory (WENO reconstruction algorithm equipped with several Riemann solvers, and (ii a central sixth-order reconstruction framework combined with various linear and nonlinear explicit low-pass spatial filtering processes. Our primary aim is to quantify the dissipative behavior, resolution characteristics, shock capturing ability and computational expenditure for each approach utilizing a systematic analysis with respect to its modeling parameters or parameterizations. The relative advantages and disadvantages of both approaches are addressed for solving a stratified Kelvin-Helmholtz instability shear layer problem as well as a canonical Riemann problem with the interaction of four shocks. The comparisons are both qualitative and quantitative, using visualizations of the spatial structure of the flow and energy spectra, respectively. We observe that the central scheme, with relaxation filtering, offers a competitive approach to ILES and is much more computationally efficient than WENO-based schemes.

  15. CPsuperH2.3: An updated tool for phenomenology in the MSSM with explicit CP violation

    Science.gov (United States)

    Lee, J. S.; Carena, M.; Ellis, J.; Pilaftsis, A.; Wagner, C. E. M.

    2013-04-01

    We describe the Fortran code CPsuperH2.3, which incorporates the following updates compared with its predecessor CPsuperH2.0. It implements improved calculations of the Higgs-boson masses and mixing including stau contributions and finite threshold effects on the tau-lepton Yukawa coupling. It incorporates the LEP limits on the processes e+e-→HiZ,HiHj and the CMS limits on Hi→τ¯τ obtained from 4.6 fb-1 of data at a center-of-mass energy of 7 TeV. It also includes the decay mode Hi→Zγ and the Schiff-moment contributions to the electric dipole moments of Mercury and Radium 225, with several calculational options for the case of Mercury. These additions make CPsuperH2.3 a suitable tool for analyzing possible CP-violating effects in the MSSM in the era of the LHC and a new generation of EDM experiments.IWB = 2,IH). Solution method: One-dimensional numerical integration for several Higgs-decay modes and EDMs, iterative treatment of the threshold corrections and Higgs-boson pole masses, and the numerical diagonalization of the neutralino mass matrix. Reasons for new version: Mainly to provide the full calculations of the EDMs of Thallium, neutron, Mercury, Deuteron, Radium, and muon as well as (gμ-2), improved calculations of the Higgs-boson masses and mixing including stau contributions, the LEP limits, the CMS limits on Hi→ττ¯, the top-quark decays, Hi→Zγ decay, and the corresponding Standard Model branching ratios of the three neutral Higgs bosons. Summary of revisions: Full calculations of the EDMs of Thallium, neutron, Mercury, Deuteron, Radium, and muon as well as (gμ-2). Improved treatment of Higgs-boson masses and mixing including stau contributions. The LEP limits. The CMS limits on Hi→ττ¯. The top-quark decays. The Hi→Zγ decay. The corresponding Standard Model branching ratios of the three neutral Higgs bosons. Running time: Less than 1.0 s.

  16. Spatially Explicit Modelling of the Belgian Major Endurance Event 'The 100 km Dodentocht'.

    Directory of Open Access Journals (Sweden)

    Steffie Van Nieuland

    Full Text Available 'The 100 km Dodentocht', which takes place annually and has its start in Bornem, Belgium, is a long distance march where participants have to cover a 100 km trail in at most 24 hours. The approximately 11 000 marchers per edition are tracked by making use of passive radio-frequency-identification (RFID. These tracking data were analyzed to build a spatially explicit marching model that gives insights into the dynamics of the event and allows to evaluate the effect of changes in the starting procedure of the event. For building the model, the empirical distribution functions (edf of the marching speeds at every section of the trail in between two consecutive checkpoints and of the checkpoints where marchers retire, are determined, taking into account age, gender, and marching speeds at previous sections. These distribution functions are then used to sample the consecutive speeds and retirement, and as such to simulate the times when individual marchers pass by the consecutive checkpoints. We concluded that the data-driven model simulates the event reliably. Furthermore, we tested three scenarios to reduce the crowdiness along the first part of the trail and in this way were able to conclude that either the start should be moved to a location outside the town center where the streets are at least 25% wider, or that the marchers should start in two groups at two different locations, and that these groups should ideally merge at about 20 km after the start. The crowdiness at the start might also be reduced by installing a bottleneck at the start in order to limit the number of marchers that can pass per unit of time. Consequently, the operating hours of the consecutive checkpoints would be longer. The developed framework can likewise be used to analyze and improve the operation of other endurance events if sufficient tracking data are available.

  17. Spatially explicit models for inference about density in unmarked or partially marked populations

    Science.gov (United States)

    Chandler, Richard B.; Royle, J. Andrew

    2013-01-01

    Recently developed spatial capture–recapture (SCR) models represent a major advance over traditional capture–recapture (CR) models because they yield explicit estimates of animal density instead of population size within an unknown area. Furthermore, unlike nonspatial CR methods, SCR models account for heterogeneity in capture probability arising from the juxtaposition of animal activity centers and sample locations. Although the utility of SCR methods is gaining recognition, the requirement that all individuals can be uniquely identified excludes their use in many contexts. In this paper, we develop models for situations in which individual recognition is not possible, thereby allowing SCR concepts to be applied in studies of unmarked or partially marked populations. The data required for our model are spatially referenced counts made on one or more sample occasions at a collection of closely spaced sample units such that individuals can be encountered at multiple locations. Our approach includes a spatial point process for the animal activity centers and uses the spatial correlation in counts as information about the number and location of the activity centers. Camera-traps, hair snares, track plates, sound recordings, and even point counts can yield spatially correlated count data, and thus our model is widely applicable. A simulation study demonstrated that while the posterior mean exhibits frequentist bias on the order of 5–10% in small samples, the posterior mode is an accurate point estimator as long as adequate spatial correlation is present. Marking a subset of the population substantially increases posterior precision and is recommended whenever possible. We applied our model to avian point count data collected on an unmarked population of the northern parula (Parula americana) and obtained a density estimate (posterior mode) of 0.38 (95% CI: 0.19–1.64) birds/ha. Our paper challenges sampling and analytical conventions in ecology by demonstrating

  18. Influence of explicit Phaeocystis parameterizations on the global distribution of marine dimethyl sulfide: Explicit Phaeocystis in a DMS Model

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shanlin [Climate Ocean and Sea Ice Modeling Group, Los Alamos National Laboratory, Los Alamos New Mexico USA; Elliott, Scott [Climate Ocean and Sea Ice Modeling Group, Los Alamos National Laboratory, Los Alamos New Mexico USA; Maltrud, Mathew [Climate Ocean and Sea Ice Modeling Group, Los Alamos National Laboratory, Los Alamos New Mexico USA; Cameron-Smith, Philip [Atmospheric, Earth, and Energy Division, Lawrence Livermore National Laboratory, Livermore California USA

    2015-11-01

    Dimethyl sulfide (DMS) is a biogenic organosulfur compound which contributes strongly to marine aerosol mass and the determination of cloud condensation nuclei over the remote oceans. Since uncertainties in DMS flux to the atmosphere lead to large variations in climate forcing, the global DMS distribution has been the subject of increasingly complex dynamic simulations. DMS concentrations are directly controlled by marine ecosystems. Phaeocystis is a major DMS producer but is often omitted from global reduced sulfur mechanisms. Here we incorporate this phytoplankton group into the marine ecosystem-biogeochemical module of the Community Earth System Model. To examine its role in the ocean sulfur cycle, an earlier DMS model has been enhanced to include new knowledge gained over the last few years. Results from the baseline run show that simulated Phaeocystis biomass generally agrees with observations, with high concentrations near the Antarctic continent and between 50° and 60° north. Given the new explicit Phaeocystis representation, the DMS distribution shows significant improvements, especially regarding the amplitude and location of high-latitude peaks. The simulated global mean surface DMS value is 2.26 nM, comparable to an estimate of 2.34 nM from the latest climatology extrapolated based on observations. The total oceanic DMS source to the atmosphere is 20.4 Tg S/yr, on the low side of previous estimates. Comparisons with and without Phaeocystis show that the group dominates DMS distributions in temperate and cold waters, contributing 13% of the global flux. The proportion may increase as sea ice declines and should be considered in climate projections.

  19. Spatially explicit Schistosoma infection risk in eastern Africa using Bayesian geostatistical modelling.

    Science.gov (United States)

    Schur, Nadine; Hürlimann, Eveline; Stensgaard, Anna-Sofie; Chimfwembe, Kingford; Mushinge, Gabriel; Simoonga, Christopher; Kabatereine, Narcis B; Kristensen, Thomas K; Utzinger, Jürg; Vounatsou, Penelope

    2013-11-01

    Schistosomiasis remains one of the most prevalent parasitic diseases in the tropics and subtropics, but current statistics are outdated due to demographic and ecological transformations and ongoing control efforts. Reliable risk estimates are important to plan and evaluate interventions in a spatially explicit and cost-effective manner. We analysed a large ensemble of georeferenced survey data derived from an open-access neglected tropical diseases database to create smooth empirical prevalence maps for Schistosoma mansoni and Schistosoma haematobium for a total of 13 countries of eastern Africa. Bayesian geostatistical models based on climatic and other environmental data were used to account for potential spatial clustering in spatially structured exposures. Geostatistical variable selection was employed to reduce the set of covariates. Alignment factors were implemented to combine surveys on different age-groups and to acquire separate estimates for individuals aged ≤20 years and entire communities. Prevalence estimates were combined with population statistics to obtain country-specific numbers of Schistosoma infections. We estimate that 122 million individuals in eastern Africa are currently infected with either S. mansoni, or S. haematobium, or both species concurrently. Country-specific population-adjusted prevalence estimates range between 12.9% (Uganda) and 34.5% (Mozambique) for S. mansoni and between 11.9% (Djibouti) and 40.9% (Mozambique) for S. haematobium. Our models revealed that infection risk in Burundi, Eritrea, Ethiopia, Kenya, Rwanda, Somalia and Sudan might be considerably higher than previously reported, while in Mozambique and Tanzania, the risk might be lower than current estimates suggest. Our empirical, large-scale, high-resolution infection risk estimates for S. mansoni and S. haematobium in eastern Africa can guide future control interventions and provide a benchmark for subsequent monitoring and evaluation activities. Copyright © 2011

  20. An explicit asymptotic preserving low Froude scheme for the multilayer shallow water model with density stratification

    Science.gov (United States)

    Couderc, F.; Duran, A.; Vila, J.-P.

    2017-08-01

    We present an explicit scheme for a two-dimensional multilayer shallow water model with density stratification, for general meshes and collocated variables. The proposed strategy is based on a regularized model where the transport velocity in the advective fluxes is shifted proportionally to the pressure potential gradient. Using a similar strategy for the potential forces, we show the stability of the method in the sense of a discrete dissipation of the mechanical energy, in general multilayer and non-linear frames. These results are obtained at first-order in space and time and extended using a second-order MUSCL extension in space and a Heun's method in time. With the objective of minimizing the diffusive losses in realistic contexts, sufficient conditions are exhibited on the regularizing terms to ensure the scheme's linear stability at first and second-order in time and space. The other main result stands in the consistency with respect to the asymptotics reached at small and large time scales in low Froude regimes, which governs large-scale oceanic circulation. Additionally, robustness and well-balanced results for motionless steady states are also ensured. These stability properties tend to provide a very robust and efficient approach, easy to implement and particularly well suited for large-scale simulations. Some numerical experiments are proposed to highlight the scheme efficiency: an experiment of fast gravitational modes, a smooth surface wave propagation, an initial propagating surface water elevation jump considering a non-trivial topography, and a last experiment of slow Rossby modes simulating the displacement of a baroclinic vortex subject to the Coriolis force.

  1. Consequences of environmental and biological variances for range margins: a spatially explicit theoretical model

    Science.gov (United States)

    Malanson, G. P.; DeRose, R. J.; Bekker, M. F.

    2016-12-01

    The consequences of increasing climatic variance while including variability among individuals and populations are explored for range margins of species with a spatially explicit simulation. The model has a single environmental gradient and a single species then extended to two species. Species response to the environment is a Gaussian function with a peak of 1.0 at their peak fitness on the gradient. The variance in the environment is taken from the total variance in the tree ring series of 399 individuals of Pinus edulis in FIA plots in the western USA. The variability is increased by a multiplier of the standard deviation for various doubling times. The variance of individuals in the simulation is drawn from these same series. Inheritance of individual variability is based on the geographic locations of the individuals. The variance for P. edulis is recomputed as time-dependent conditional standard deviations using the GARCH procedure. Establishment and mortality are simulated in a Monte Carlo process with individual variance. Variance for P. edulis does not show a consistent pattern of heteroscedasticity. An obvious result is that increasing variance has deleterious effects on species persistence because extreme events that result in extinctions cannot be balanced by positive anomalies, but even less extreme negative events cannot be balanced by positive anomalies because of biological and spatial constraints. In the two species model the superior competitor is more affected by increasing climatic variance because its response function is steeper at the point of intersection with the other species and so the uncompensated effects of negative anomalies are greater for it. These theoretical results can guide the anticipated need to mitigate the effects of increasing climatic variability on P. edulis range margins. The trailing edge, here subject to increasing drought stress with increasing temperatures, will be more affected by negative anomalies.

  2. Alien wavelength modeling tool and field trial

    DEFF Research Database (Denmark)

    Sambo, N.; Sgambelluri, A.; Secondini, M.

    2015-01-01

    A modeling tool is presented for pre-FEC BER estimation of PM-QPSK alien wavelength signals. A field trial is demonstrated and used as validation of the tool's correctness. A very close correspondence between the performance of the field trial and the one predicted by the modeling tool has been...

  3. A new approach to spatially explicit modelling of forest dynamics: spacing, ageing and neighbourhood competition of mangrove trees

    NARCIS (Netherlands)

    Berger, U.; Hildenbrandt, H.

    2000-01-01

    This paper presents a new approach to spatially explicit modelling that enables the influence of neighbourhood effects on the dynamics of forests and plant communities to be analysed. We refer to this approach as 'field of neighbourhood' (FON). It combines the 'neighbourhood philosophy' of

  4. Alcohol's dissociation of implicit and explicit memory processes: implications of a parallel distributed processing model of semantic priming.

    Science.gov (United States)

    Ray, Suchismita; Bates, Marsha E; Ely, Benjamin Martin

    2004-05-01

    Alcohol's dissociation of implicit (unintentional) and explicit (intentional) memory processes in social drinkers was examined. It was hypothesized that an alcohol challenge would lower the percentage of words recalled and result in more retroactive interference in explicit recall tasks but would not lengthen reaction time in an implicit semantic priming task involving highly semantically similar words. Men and women completed all memory tasks in each of 2 counterbalanced sessions (alcohol challenge vs. no-alcohol) separated by 1 week. Alcohol significantly degraded processing in both explicit memory tasks, yet implicit semantic priming remained intact. A parallel distributed processing model that simulates semantic memory is presented. When this system is strongly activated, it does not appear to be altered during moderate alcohol intoxication. ((c) 2004 APA, all rights reserved)

  5. Maquis fuel model development to support spatially-explicit fire modeling applications

    OpenAIRE

    Bacciu, Valentina Maria

    2009-01-01

    The availability of accurate data on conditions and spatial distribution of fuels has been shown to be critical in numerous topics of fire studies. In Italy, there is a lack of studies devoted to a systematic analysis of the vegetation characteristics related to fire behaviour, thus involving the use of fuel data and fuel models developed in other countries. In this perspective, the aim of this work is to propose an integrated approach to fuel model development and assessment based on fiel...

  6. Explicit Interaction

    DEFF Research Database (Denmark)

    Löwgren, Jonas; Eriksen, Mette Agger; Linde, Per

    2006-01-01

    as an interpretation of palpability, comprising usability as well as patient empowerment and socially performative issues. We present a prototype environment for video recording during physiotherapeutical consultation which illustrates our current thoughts on explicit interaction and serves as material for further...

  7. Comparison of Implicit and Explicit Solvent Models for the Calculation of Solvation Free Energy in Organic Solvents.

    Science.gov (United States)

    Zhang, Jin; Zhang, Haiyang; Wu, Tao; Wang, Qi; van der Spoel, David

    2017-03-14

    Quantitative prediction of physical properties of liquids is important for many applications. Computational methods based on either explicit or implicit solvent models can be used to approximate thermodynamics properties of liquids. Here, we evaluate the predictive power of implicit solvent models for solvation free energy of organic molecules in organic solvents. We compared the results calculated with four generalized Born (GB) models (GBStill, GBHCT, GBOBCI, and GBOBCII), the Poisson-Boltzmann (PB) model, and the density-based solvent model SMD with previous solvation free energy calculations (Zhang et al. J. Chem. Inf. 2015, 55, 1192-1201) and experimental data. The comparison indicates that both PB and GB give poor agreement with explicit solvent calculations and even worse agreement with experiments (root-mean-square deviation ≈ 15 kJ/mol). The main problem seems to be the prediction of the apolar contribution, which should include the solvent entropy. The quantum mechanical-based SMD model gives significantly better agreement with experimental data than do PB or GB, but it is not as good as explicit solvent calculation results. The dielectric constant ε of the solvent is found to be a powerful predictor for the polar contribution to the free energy in implicit models; however, the Onsager relation may not hold for realistic solvent, as suggested by explicit solvent and SMD calculations. From the comparison, we also find that with an optimization of the apolar contribution, the PB model gives slightly better agreement with experiments than the SMD model, whereas the correlation between the optimized GB models and experiments remains poor. Further optimization of the apolar contribution is needed for GB models to be able to treat solvents other than water.

  8. Spatially-explicit model of mercury accumulation in the forest floor of the United States

    Science.gov (United States)

    Perry, C. H.; Zimmerman, P.

    2009-12-01

    Atmospherically-deposited Hg has a strong affinity for soil organic matter. The Forest Service, US Department of Agriculture, Forest Inventory and Analysis (FIA) program collects soil samples from forested areas across the United States as part of its sampling program, and annual soils inventories are underway or completed in 46 of the 50 states (Alaska, Hawaii, New Mexico, and Oklahoma have yet to be sampled). Our objective is to describe the spatial distribution of forest floor Hg for a transect running across the United States, from Arizona in the southwest to Maine in the northeast. The collection of forest floor samples was accomplished as part of the standard FIA Phase 3 Soil Quality Indicator program. Field protocols include the measurement of the thickness of the forest floor and the collection of the entire forest floor found within a 30-cm diameter sampling frame. We removed approximately 0.1 g of the sample for plots in our region of interest, and these were sent to two different laboratories for Hg analysis by cold-vapor atomic absorption. The two laboratories calibrated their instruments against common Hg standards. We found good agreement between samples analyzed at both laboratories. Observations of mercury concentrations were joined with the Forest Inventory and Analysis Database and other geospatial databases to assign basic location information and associated inventory data. Ecoprovince and forest-type group are significant predictors of Hg storage; conifer species tend to store more mercury than hardwood species. Additionally, models created using spatially-explicit techniques yield distinct patterns of Hg storage that vary across forest-type groups.

  9. Detection and modelling of contacts in explicit finite-element simulation of soft tissue biomechanics.

    Science.gov (United States)

    Johnsen, S F; Taylor, Z A; Han, L; Hu, Y; Clarkson, M J; Hawkes, D J; Ourselin, S

    2015-11-01

    Realistic modelling of soft tissue biomechanics and mechanical interactions between tissues is an important part of biomechanically-informed surgical image-guidance and surgical simulation. This submission details a contact-modelling pipeline suitable for implementation in explicit matrix-free FEM solvers. While these FEM algorithms have been shown to be very suitable for simulation of soft tissue biomechanics and successfully used in a number of image-guidance systems, contact modelling specifically for these solvers is rarely addressed, partly because the typically large number of time steps required with this class of FEM solvers has led to a perception of them being a poor choice for simulations requiring complex contact modelling. The presented algorithm is capable of handling most scenarios typically encountered in image-guidance. The contact forces are computed with an evolution of the Lagrange-multiplier method first used by Taylor and Flanagan in PRONTO 3D extended with spatio-temporal smoothing heuristics for improved stability and edge-edge collision handling, and a new friction model. For contact search, a bounding-volume hierarchy (BVH) is employed, which is capable of identifying self-collisions by means of the surface-normal bounding cone of Volino and Magnenat-Thalmann, in turn computed with a novel formula. The BVH is further optimised for the small time steps by reducing the number of bounding-volume refittings between iterations through identification of regions with mostly rigid motion and negligible deformation. Further optimisation is achieved by integrating the self-collision criterion in the BVH creation and updating algorithms. The effectiveness of the algorithm is demonstrated on a number of artificial test cases and meshes derived from medical image data. It is shown that the proposed algorithm reduces the cost of BVH refitting to the point where it becomes a negligible part of the overall computation time of the simulation. It is also

  10. Spatially explicit neutral models for population genetics and community ecology: Extensions of the Neyman-Scott clustering process.

    Science.gov (United States)

    Shimatani, Ichiro K

    2010-02-01

    Spatially explicit models relating to plant populations have developed little since Felsenstein (1975) pointed out that if limited seed dispersal causes clustering of individuals, such models cannot reach an equilibrium. This paper aims to resolve this issue by modifying the Neyman-Scott cluster point process. The new point processes are dynamic models with random immigration, and the continuous increase in the clustering of individuals stops at some level. Hence, an equilibrium state is achieved, and new individual-based spatially explicit neutral coalescent models are established. By fitting the spatial structure at equilibrium to individual spatial distribution data, we can indirectly estimate seed dispersal and effective population density. These estimates are improved when genetic data are available, and become even more sophisticated if spatial distribution and genetic data pertaining to the offspring are also available. Copyright 2009 Elsevier Inc. All rights reserved.

  11. Performability Modelling Tools, Evaluation Techniques and Applications

    NARCIS (Netherlands)

    Haverkort, Boudewijn R.H.M.

    1990-01-01

    This thesis deals with three aspects of quantitative evaluation of fault-tolerant and distributed computer and communication systems: performability evaluation techniques, performability modelling tools, and performability modelling applications. Performability modelling is a relatively new

  12. Explicit time integration of finite element models on a vectorized, concurrent computer with shared memory

    Science.gov (United States)

    Gilbertsen, Noreen D.; Belytschko, Ted

    1990-01-01

    The implementation of a nonlinear explicit program on a vectorized, concurrent computer with shared memory is described and studied. The conflict between vectorization and concurrency is described and some guidelines are given for optimal block sizes. Several example problems are summarized to illustrate the types of speed-ups which can be achieved by reprogramming as compared to compiler optimization.

  13. Explicit targeting of transformed cells by VSV in ovarian epithelial tumor-bearing Wv mouse models.

    Science.gov (United States)

    Capo-chichi, Callinice D; Yeasky, Toni M; Heiber, Joshua F; Wang, Ying; Barber, Glen N; Xu, Xiang-Xi

    2010-02-01

    -neoplastic to overt cancer cells. The results demonstrated the explicit targeting of ovarian epithelial tumors by VSV in immune competent, ovarian tumor-bearing mouse models, and further support the utility of VSV as an effective and safe anti-cancer agent. Copyright 2009 Elsevier Inc. All rights reserved.

  14. Cirrus Parcel Model Comparison Project. Phase 1; The Critical Components to Simulate Cirrus Initiation Explicitly

    Science.gov (United States)

    Lin, Ruei-Fong; Starr, David OC; DeMott, Paul J.; Cotton, Richard; Sassen, Kenneth; Jensen, Eric; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The Cirrus Parcel Model Comparison Project, a project of the GCSS (GEWEX Cloud System Studies) Working Group on Cirrus Cloud Systems, involves the systematic comparison of current models of ice crystal nucleation and growth for specified, typical, cirrus cloud environments. In Phase I of the project reported here, simulated cirrus cloud microphysical properties are compared for situations of "warm" (40 C) and "cold" (-60 C) cirrus, both subject to updrafts of 4, 20 and 100 centimeters per second. Five models participated. The various models employ explicit microphysical schemes wherein the size distribution of each class of particles (aerosols and ice crystals) is resolved into bins or treated separately. Simulations are made including both the homogeneous and heterogeneous ice nucleation mechanisms. A single initial aerosol population of sulfuric acid particles is prescribed for all simulations. To isolate the treatment of the homogeneous freezing (of haze droplets) nucleation process, the heterogeneous nucleation mechanism is disabled for a second parallel set of simulations. Qualitative agreement is found for the homogeneous-nucleation- only simulations, e.g., the number density of nucleated ice crystals increases with the strength of the prescribed updraft. However, significant quantitative differences are found. Detailed analysis reveals that the homogeneous nucleation rate, haze particle solution concentration, and water vapor uptake rate by ice crystal growth (particularly as controlled by the deposition coefficient) are critical components that lead to differences in predicted microphysics. Systematic bias exists between results based on a modified classical theory approach and models using an effective freezing temperature approach to the treatment of nucleation. Each approach is constrained by critical freezing data from laboratory studies, but each includes assumptions that can only be justified by further laboratory research. Consequently, it is not yet

  15. Fire behavior modeling-a decision tool

    Science.gov (United States)

    Jack Cohen; Bill Bradshaw

    1986-01-01

    The usefulness of an analytical model as a fire management decision tool is determined by the correspondence of its descriptive capability to the specific decision context. Fire managers must determine the usefulness of fire models as a decision tool when applied to varied situations. Because the wildland fire phenomenon is complex, analytical fire spread models will...

  16. Explicit Solutions for the Solomon-Wilson-Alexiades’s Mushy Zone Model with Convective or Heat Flux Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Domingo A. Tarzia

    2015-01-01

    Full Text Available We complete the Solomon-Wilson-Alexiades’s mushy zone model (Solomon, 1982 for the one-phase Lamé-Clapeyron-Stefan problem by obtaining explicit solutions when a convective or heat flux boundary condition is imposed on the fixed face for a semi-infinite material. We also obtain the necessary and sufficient condition on data in order to get the explicit solutions for both cases which is new with respect to the original model. Moreover, when these conditions are satisfied, the two phase-change problems are equivalent to the same problem with a temperature boundary condition on the fixed face and therefore an inequality for the coefficient which characterized one of the two free interfaces of the model is also obtained.

  17. EPS Mid-Career Award 2011. Are there multiple memory systems? Tests of models of implicit and explicit memory.

    Science.gov (United States)

    Shanks, David R; Berry, Christopher J

    2012-01-01

    This article reviews recent work aimed at developing a new framework, based on signal detection theory, for understanding the relationship between explicit (e.g., recognition) and implicit (e.g., priming) memory. Within this framework, different assumptions about sources of memorial evidence can be framed. Application to experimental results provides robust evidence for a single-system model in preference to multiple-systems models. This evidence comes from several sources including studies of the effects of amnesia and ageing on explicit and implicit memory. The framework allows a range of concepts in current memory research, such as familiarity, recollection, fluency, and source memory, to be linked to implicit memory. More generally, this work emphasizes the value of modern computational modelling techniques in the study of learning and memory.

  18. ATL: a model transformation tool

    NARCIS (Netherlands)

    Jouault, Frédéric; Allilaire, Freddy; Bézivin, Jean; Ivanov, Ivan

    2008-01-01

    In the context of Model Driven Engineering, models are the main development artifacts and model transformations are among the most important operations applied to models. A number of specialized languages have been proposed, aimed at specifying model transformations. Apart from the software

  19. CPsuperH2.0 an Improved Computational Tool for Higgs Phenomenology in the MSSM with Explicit CP Violation

    CERN Document Server

    Lee, J S; Ellis, Jonathan Richard; Pilaftsis, Apostolos; Wagner, C E M

    2009-01-01

    We describe the Fortran code CPsuperH2.0, which contains several improvements and extensions of its predecessor CPsuperH. It implements improved calculations of the Higgs-boson pole masses, notably a full treatment of the 4×4 neutral Higgs propagator matrix including the Goldstone boson and a more complete treatment of threshold effects in self-energies and Yukawa couplings, improved treatments of two-body Higgs decays, some important three-body decays, and two-loop Higgs-mediated contributions to electric dipole moments. CPsuperH2.0 also implements an integrated treatment of several B-meson observables, including the branching ratios of Bs→μ+μ−, Bd→τ+τ−, Bu→τν, B→Xsγ and the latter's CP-violating asymmetry acp, and the [...]supersymmetric contributions to the mass differences. These additions make CPsuperH2.0 an attractive integrated tool for analyzing supersymmetric CP and flavour physics as well as searches for new physics at high-energy colliders such as the Tevatron, LHC and linear co...

  20. Requirements for clinical information modelling tools.

    Science.gov (United States)

    Moreno-Conde, Alberto; Jódar-Sánchez, Francisco; Kalra, Dipak

    2015-07-01

    This study proposes consensus requirements for clinical information modelling tools that can support modelling tasks in medium/large scale institutions. Rather than identify which functionalities are currently available in existing tools, the study has focused on functionalities that should be covered in order to provide guidance about how to evolve the existing tools. After identifying a set of 56 requirements for clinical information modelling tools based on a literature review and interviews with experts, a classical Delphi study methodology was applied to conduct a two round survey in order to classify them as essential or recommended. Essential requirements are those that must be met by any tool that claims to be suitable for clinical information modelling, and if we one day have a certified tools list, any tool that does not meet essential criteria would be excluded. Recommended requirements are those more advanced requirements that may be met by tools offering a superior product or only needed in certain modelling situations. According to the answers provided by 57 experts from 14 different countries, we found a high level of agreement to enable the study to identify 20 essential and 21 recommended requirements for these tools. It is expected that this list of identified requirements will guide developers on the inclusion of new basic and advanced functionalities that have strong support by end users. This list could also guide regulators in order to identify requirements that could be demanded of tools adopted within their institutions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  1. An explicit continuous analytical model for Gate All Around (GAA) MOSFETs including the hot-carrier degradation effects.

    Science.gov (United States)

    Abdi, M A; Djeffal, F; Bentrcia, T; Arar, D

    2011-10-01

    In this paper, an explicit and continuous analytical model including interfacial hot-carrier effects is developed for a deep submicron Gate All Around (GAA) MOSFETs. Explicit analytical expressions of the surface potential, drain current and transconductance are given for all operating modes. Exploiting this new device model, we have found that the incorporation of a high-k layer, Gate Stack (GS), between oxide region and gate metal leads to drain current enhancement, improved transconductance parameter and enhanced interfacial hot-carrier immunity. The developed approaches are verified and validated by the good agreement found with the 2D numerical simulations for wide range of device parameters and bias conditions. GS GAA MOSFET design can alleviate the critical problem and further improve the immunity of hot-carrier effects of GAA MOSFET-based circuits in the deep submicron working domain.

  2. Towards a more explicit representation of soil microbial community in soil carbon and nitrogen dynamics models: a review

    Science.gov (United States)

    Louis, Benjamin; Viaud, Valérie; Leterme, Philippe; Maron, Pierre-Alain; Menasseri-Aubry, Safya

    2015-04-01

    The need to understand and predict the soil carbon and nitrogen dynamics has led to an increase of models development in the last century. Both concept and accuracy of these models have been largely studied. One of the most influent debates in model development is about the place of soil microorganisms in these models. Difficulties in linking microbial communities with soil carbon and nitrogen dynamics have participated to a largely non-explicit representation of the role of microbial communities in these models. The objective of this work was to get a state of the art overview of studies which have worked in linking soil microbial diversity and community composition to carbon and nitrogen dynamics helping by last advances in molecular biology. How recent models represent these microbial characteristics is then reviewed and some directions for future research in carbon and nitrogen dynamics modelling are proposed. Last advances of molecular biology have permitted to better apprehend the role of microorganisms. Review of microbial communities - soil carbon and nitrogen dynamics relations studies shows that even if a lot of unknown is still to be unravelled, there is a great interest of taking into account more explicitly the role of microbial communities in carbon and nitrogen dynamics. Last studies on diversity erosion impact in soil carbon and nitrogen dynamics show that the microbial diversity is non neutral. Moreover, microbial communities' composition could also have a relative importance. As microbial communities characteristics are largely driven both by pedoclimatic factors and agricultural management and their interactions, these characteristics constitute a link between interactions of pedoclimatic factors and agricultural management and soil carbon and nitrogen dynamics. Explicitly including these characteristics could improve models quality, especially for models devoted to realistic predictions of these dynamics in numerous agricultural contexts

  3. 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...

  4. Methods used to parameterize the spatially-explicit components of a state-and-transition simulation model

    Science.gov (United States)

    Sleeter, Rachel; Acevedo, William; Soulard, Christopher E.; Sleeter, Benjamin M.

    2015-01-01

    Spatially-explicit state-and-transition simulation models of land use and land cover (LULC) increase our ability to assess regional landscape characteristics and associated carbon dynamics across multiple scenarios. By characterizing appropriate spatial attributes such as forest age and land-use distribution, a state-and-transition model can more effectively simulate the pattern and spread of LULC changes. This manuscript describes the methods and input parameters of the Land Use and Carbon Scenario Simulator (LUCAS), a customized state-and-transition simulation model utilized to assess the relative impacts of LULC on carbon stocks for the conterminous U.S. The methods and input parameters are spatially explicit and describe initial conditions (strata, state classes and forest age), spatial multipliers, and carbon stock density. Initial conditions were derived from harmonization of multi-temporal data characterizing changes in land use as well as land cover. Harmonization combines numerous national-level datasets through a cell-based data fusion process to generate maps of primary LULC categories. Forest age was parameterized using data from the North American Carbon Program and spatially-explicit maps showing the locations of past disturbances (i.e. wildfire and harvest). Spatial multipliers were developed to spatially constrain the location of future LULC transitions. Based on distance-decay theory, maps were generated to guide the placement of changes related to forest harvest, agricultural intensification/extensification, and urbanization. We analyze the spatially-explicit input parameters with a sensitivity analysis, by showing how LUCAS responds to variations in the model input. This manuscript uses Mediterranean California as a regional subset to highlight local to regional aspects of land change, which demonstrates the utility of LUCAS at many scales and applications.

  5. Methods used to parameterize the spatially-explicit components of a state-and-transition simulation model

    Directory of Open Access Journals (Sweden)

    Rachel R. Sleeter

    2015-06-01

    Full Text Available Spatially-explicit state-and-transition simulation models of land use and land cover (LULC increase our ability to assess regional landscape characteristics and associated carbon dynamics across multiple scenarios. By characterizing appropriate spatial attributes such as forest age and land-use distribution, a state-and-transition model can more effectively simulate the pattern and spread of LULC changes. This manuscript describes the methods and input parameters of the Land Use and Carbon Scenario Simulator (LUCAS, a customized state-and-transition simulation model utilized to assess the relative impacts of LULC on carbon stocks for the conterminous U.S. The methods and input parameters are spatially explicit and describe initial conditions (strata, state classes and forest age, spatial multipliers, and carbon stock density. Initial conditions were derived from harmonization of multi-temporal data characterizing changes in land use as well as land cover. Harmonization combines numerous national-level datasets through a cell-based data fusion process to generate maps of primary LULC categories. Forest age was parameterized using data from the North American Carbon Program and spatially-explicit maps showing the locations of past disturbances (i.e. wildfire and harvest. Spatial multipliers were developed to spatially constrain the location of future LULC transitions. Based on distance-decay theory, maps were generated to guide the placement of changes related to forest harvest, agricultural intensification/extensification, and urbanization. We analyze the spatially-explicit input parameters with a sensitivity analysis, by showing how LUCAS responds to variations in the model input. This manuscript uses Mediterranean California as a regional subset to highlight local to regional aspects of land change, which demonstrates the utility of LUCAS at many scales and applications.

  6. Evaluating the effect of corridors and landscape heterogeneity on dispersal probability: a comparison of three spatially explicit modelling approaches

    DEFF Research Database (Denmark)

    Jepsen, J. U.; Baveco, J. M.; Topping, C. J.

    2004-01-01

    Spatially explicit simulation models of varying degree of complexity are increasingly used in landscape and species management and conservation. The choice as to which type of model to employ in a particular situation, is however, far too often governed by logistic constraints and the personal...... and demographics (IBPM)). The IBPM was analysed in two versions (IBPM_st and IBPM_dyn). Both assumed spatial heterogeneity of the matrix, but the IBPM_dyn in addition included temporal matrix dynamics. The models were developed with a shared minimum objective, namely to predict dynamics of individuals...

  7. Software Engineering Tools for Scientific Models

    Science.gov (United States)

    Abrams, Marc; Saboo, Pallabi; Sonsini, Mike

    2013-01-01

    Software tools were constructed to address issues the NASA Fortran development community faces, and they were tested on real models currently in use at NASA. These proof-of-concept tools address the High-End Computing Program and the Modeling, Analysis, and Prediction Program. Two examples are the NASA Goddard Earth Observing System Model, Version 5 (GEOS-5) atmospheric model in Cell Fortran on the Cell Broadband Engine, and the Goddard Institute for Space Studies (GISS) coupled atmosphere- ocean model called ModelE, written in fixed format Fortran.

  8. Model Checking Markov Chains: Techniques and Tools

    NARCIS (Netherlands)

    Zapreev, I.S.

    2008-01-01

    This dissertation deals with four important aspects of model checking Markov chains: the development of efficient model-checking tools, the improvement of model-checking algorithms, the efficiency of the state-space reduction techniques, and the development of simulation-based model-checking

  9. Propel: Tools and Methods for Practical Source Code Model Checking

    Science.gov (United States)

    Mansouri-Samani, Massoud; Mehlitz, Peter; Markosian, Lawrence; OMalley, Owen; Martin, Dale; Moore, Lantz; Penix, John; Visser, Willem

    2003-01-01

    The work reported here is an overview and snapshot of a project to develop practical model checking tools for in-the-loop verification of NASA s mission-critical, multithreaded programs in Java and C++. Our strategy is to develop and evaluate both a design concept that enables the application of model checking technology to C++ and Java, and a model checking toolset for C++ and Java. The design concept and the associated model checking toolset is called Propel. It builds upon the Java PathFinder (JPF) tool, an explicit state model checker for Java applications developed by the Automated Software Engineering group at NASA Ames Research Center. The design concept that we are developing is Design for Verification (D4V). This is an adaption of existing best design practices that has the desired side-effect of enhancing verifiability by improving modularity and decreasing accidental complexity. D4V, we believe, enhances the applicability of a variety of V&V approaches; we are developing the concept in the context of model checking. The model checking toolset, Propel, is based on extending JPF to handle C++. Our principal tasks in developing the toolset are to build a translator from C++ to Java, productize JPF, and evaluate the toolset in the context of D4V. Through all these tasks we are testing Propel capabilities on customer applications.

  10. ANSYS tools in modeling tires

    Science.gov (United States)

    Ali, Ashraf; Lovell, Michael

    1995-01-01

    This presentation summarizes the capabilities in the ANSYS program that relate to the computational modeling of tires. The power and the difficulties associated with modeling nearly incompressible rubber-like materials using hyperelastic constitutive relationships are highlighted from a developer's point of view. The topics covered include a hyperelastic material constitutive model for rubber-like materials, a general overview of contact-friction capabilities, and the acoustic fluid-structure interaction problem for noise prediction. Brief theoretical development and example problems are presented for each topic.

  11. Modeling spatially- and temporally-explicit water stress indices for use in life cycle assessment

    Science.gov (United States)

    Scherer, L.; Venkatesh, A.; Karuppiah, R.; Usadi, A.; Pfister, S.; Hellweg, S.

    2013-12-01

    Water scarcity is a regional issue in many areas across the world, and can affect human health and ecosystems locally. Water stress indices (WSIs) have been developed as quantitative indicators of such scarcities - examples include the Falkenmark indicator, Social Water Stress Index, and the Water Supply Stress Index1. Application of these indices helps us understand water supply and demand risks for multiple users, including those in the agricultural, industrial, residential and commercial sectors. Pfister et al.2 developed a method to calculate WSIs that were used to estimate characterization factors (CFs) in order to quantify environmental impacts of freshwater consumption within a life cycle assessment (LCA) framework. Global WSIs were based on data from the WaterGAP model3, and presented as annual averages for watersheds. Since water supply and demand varies regionally and temporally, the resolution used in Pfister et al. does not effectively differentiate between seasonal and permanent water scarcity. This study aims to improve the temporal and spatial resolution of the water scarcity calculations used to estimate WSIs and CFs. We used the Soil and Water Assessment Tool (SWAT)4 hydrological model to properly simulate water supply in different world regions with high spatial and temporal resolution, and coupled it with water use data from WaterGAP3 and Pfister et al.5. Input data to SWAT included weather, land use, soil characteristics and a digital elevation model (DEM), all from publicly available global data sets. Potential evapotranspiration, which affects water supply, was determined using an improved Priestley-Taylor approach. In contrast to most other hydrological studies, large reservoirs, water consumption and major water transfers were simulated. The model was calibrated against observed monthly discharge, actual evapotranspiration, and snow water equivalents wherever appropriate. Based on these simulations, monthly WSIs were calculated for a few

  12. Fuzzy tool for conceptual modeling under uncertainty

    Science.gov (United States)

    Walek, Bogdan; Klimes, Cyril

    2012-01-01

    This paper deals with the design of fuzzy tool for creating conceptual model under uncertainty. The paper identifies a problem in current approach of creating conceptual model of information system and suggests new methodics and tool for creating conceptual model, which can processes uncertain user requirements. The proposed tool uses a general model of the decision support system, that works with the vague input values and IF-THEN fuzzy rules, and creates a list of appropriate and acceptable solutions, and then allows to choose the best solution. In the proposed tool entities, attributes and relations between entitites in the resulting conceptual model are selected via a decision support system. In the paper we present six main parts of proposed tool, that generates suitable entities, attributes and relations between entities, then generates them to XML format and finally visualizes the resulting conceptual model. The created conceptual model illustrates the analysis of information system requirements. The proposed tool is shown on creating conceptual model of the hotel information system.

  13. Spatially explicit habitat models for 28 fishes from the Upper Mississippi River System (AHAG 2.0)

    Science.gov (United States)

    Ickes, Brian S.; Sauer, J.S.; Richards, N.; Bowler, M.; Schlifer, B.

    2014-01-01

    species; occurrences at sampling sites as observed in day electrofishing samples) using multiple logistic regression with presence/absence responses. Each species’ probability of occurrence, at each sample site, was modeled as a function of 17 environmental variables observed at each sample site by LTRMP standardized protocols. The modeling methods used (1) a forward-selection process to identify the most important predictors and their relative contributions to predictions; (2) partial methods on the predictor set to control variance inflation; and (3) diagnostics for LTRMP design elements that may influence model fits. Models were fit for 28 species, representing 3 habitat guilds (Lentic, Lotic, and Generalist). We intended to develop “systemic models” using data from all six LTRMP study reaches simultaneously; however, this proved impossible. Thus, we “regionalized” the models, creating two models for each species: “Upper Reach” models, using data from Pools 4, 8, and 13; and “Lower Reach” models, using data from Pool 26, the Open River Reach of the Mississippi River, and the La Grange reach of the Illinois River. A total of 56 models were attempted. For any given site-scale prediction, each model used data from the three LTRMP study reaches comprising the regional model to make predictions. For example, a site-scale prediction in Pool 8 was made using data from Pools 4, 8, and 13. This is the fundamental nature and trade-off of regionalizing these models for broad management application. Model fits were deemed “certifiably good” using the Hosmer and Lemeshow Goodness-of-Fit statistic (Hosmer and Lemeshow, 2000). This test post-partitions model predictions into 10 groups and conducts inferential tests on correspondences between observed and expected probability of occurrence across all partitions, under Chi-square distributional assumptions. This permits an inferential test of how well the models fit and a tool for reporting when they did not (and

  14. Spatially explicit modeling of 1992-2100 land cover and forest stand age for the conterminous United States

    Science.gov (United States)

    Sohl, Terry L.; Sayler, Kristi L.; Bouchard, Michelle; Reker, Ryan R.; Friesz, Aaron M.; Bennett, Stacie L.; Sleeter, Benjamin M.; Sleeter, Rachel R.; Wilson, Tamara; Soulard, Christopher E.; Knuppe, Michelle; Van Hofwegen, Travis

    2014-01-01

    Information on future land-use and land-cover (LULC) change is needed to analyze the impact of LULC change on ecological processes. The U.S. Geological Survey has produced spatially explicit, thematically detailed LULC projections for the conterminous United States. Four qualitative and quantitative scenarios of LULC change were developed, with characteristics consistent with the Intergovernmental Panel on Climate Change (IPCC) Special Report on 5 Emission Scenarios (SRES). The four quantified scenarios (A1B, A2, B1, and B2) served as input to the Forecasting Scenarios of Land-use Change (FORE-SCE) model. Four spatially explicit datasets consistent with scenario storylines were produced for the conterminous United States, with annual LULC maps from 1992 through 2100. The future projections are characterized by a loss of natural land covers in most scenarios, with corresponding expansion of 10 anthropogenic land uses. Along with the loss of natural land covers, remaining natural land covers experience increased fragmentation under most scenarios, with only the B2 scenario remaining relatively stable in both proportion of remaining natural land covers and basic fragmentation measures. Forest stand age was also modeled. By 2100, scenarios and ecoregions with heavy forest cutting have relatively lower mean stand ages compared to those with less 15 forest cutting. Stand ages differ substantially between unprotected and protected forest lands, as well as between different forest classes. The modeled data were compared to the National Land Cover Database (NLCD) and other data sources to assess model characteristics. The consistent, spatially explicit, and thematically detailed LULC projections and the associated forest stand age data layers have been used to analyze LULC impacts on carbon and greenhouse gas fluxes, 20 biodiversity, climate and weather variability, hydrologic change, and other ecological processes.

  15. Spatially explicit modeling of 1992-2100 land cover and forest stand age for the conterminous United States.

    Science.gov (United States)

    Sohl, Terry L; Sayler, Kristi L; Bouchard, Michelle A; Reker, Ryan R; Friesz, Aaron M; Bennett, Stacie L; Sleeter, Benjamin M; Sleeter, Rachel R; Wilson, Tamara; Soulard, Chris; Knuppe, Michelle; Van Hofwegen, Travis

    2014-07-01

    Information on future land-use and land-cover (LULC) change is needed to analyze the impact of LULC change on ecological processes. The U.S. Geological Survey has produced spatially explicit, thematically detailed LULC projections for the conterminous United States. Four qualitative and quantitative scenarios of LULC change were developed, with characteristics consistent with the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES). The four quantified scenarios (A1B, A2, B1, and B2) served as input to the forecasting scenarios of land-use change (FORE-SCE) model. Four spatially explicit data sets consistent with scenario storylines were produced for the conterminous United States, with annual LULC maps from 1992 through 2100. The future projections are characterized by a loss of natural land covers in most scenarios, with corresponding expansion of anthropogenic land uses. Along with the loss of natural land covers, remaining natural land covers experience increased fragmentation under most scenarios, with only the B2 scenario remaining relatively stable in both the proportion of remaining natural land covers and basic fragmentation measures. Forest stand age was also modeled. By 2100, scenarios and ecoregions with heavy forest cutting had relatively lower mean stand ages compared to those with less forest cutting. Stand ages differed substantially between unprotected and protected forest lands, as well as between different forest classes. The modeled data were compared to the National Land Cover Database (NLCD) and other data sources to assess model characteristics. The consistent, spatially explicit, and thematically detailed LULC projections and the associated forest stand-age data layers have been used to analyze LULC impacts on carbon and greenhouse gas fluxes, biodiversity, climate and weather variability, hydrologic change, and other ecological processes.

  16. Spatially-explicit LCIA model for marine eutrophication as a tool for sustainability assessment

    DEFF Research Database (Denmark)

    Cosme, Nuno Miguel Dias; Hauschild, Michael Zwicky

    2014-01-01

    quality as potentially affected fraction of species (PAF) per mass of N emitted to the environment, volume and time integrated, or (PAF·)[m3·yr·kg-1]. Preliminary results present spatially differentiated CFs for 214 country-to-ecosystem combinations and for 143 countries. Such CFs can be implemented...

  17. Mechanisms for Solvatochromic Shifts of Free-Base Porphine Studied with Polarizable Continuum Models and Explicit Solute-Solvent Interactions.

    Science.gov (United States)

    Fukuda, Ryoichi; Ehara, Masahiro

    2013-01-08

    Solvatochromic shifts of free-base porphine in the Q-band and B-band were studied using the polarizable continuum model (PCM) and explicit solvent molecules employing time-dependent density functional theory (TDDFT) and the symmetry-adapted cluster-configuration interaction (SAC-CI) method. The state-specific (SS) and linear-response (LR) methods were examined in the PCM calculations. These models involve different types of solute-solvent interactions. The LR PCM and explicit solvation models reproduced the experimentally observed trends of the solvatochromic shifts, while the SS PCM failed to reproduce the experimental findings. The origin of the solvatochromic shifts of free-base porphine was dispersive interactions between the solute and solvent. Specific solute-solvent interactions would be important for a decrease of the splitting width between Q-bands. Based on the Casimir-Polder formula and a decomposition analysis, it was found that the dominant part of the solute-solvent interactions can be considered using independent particle approximations.

  18. A Spatially Explicit and Seasonally Varying Cholera Prevalence Model With Distributed Macro-Scale Environmental and Hydroclimatic Forcings

    Science.gov (United States)

    Akanda, A. S.; Jutla, A. S.; Eltahir, E. A.; Islam, S.

    2011-12-01

    Despite major advances in the ecological and microbiological understanding of the bacterium Vibrio cholerae, the role of underlying large-scale processes in the progression of the cholera disease in space and time is not well understood. Here, we present a spatially explicit and seasonally varying coupled hydroclimatology-epidemiology model for understanding regional scale cholera prevalence in response to large scale hydroclimatic and environmental forcings. Our results show that environmental cholera transmission can be modulated by two spatially and seasonally distinct mechanisms - influenced by dry and wet season hydrologic determinants. The model is applied to the Ganges-Brahmaputra-Meghna Basin areas in Bangladesh to simulate spatially explicit cholera prevalence rates, and validated with long-term cholera data from Dhaka and shorter-term records from regional surveillance locations. The model reproduces the variability of cholera prevalence at monthly, seasonal, and interannual timescales and highlights the role of asymmetric large scale hydroclimatic processes as the dominant controls. Our findings have important implications for formulating effective cholera intervention strategies, and for understanding the impacts of changing climate patterns on seasonal cholera transmission.

  19. Development and Analysis of Advanced Explicit Algebraic Turbulence and Scalar Flux Models for Complex Engineering Configurations

    OpenAIRE

    Yun, Alexander

    2005-01-01

    In spite of today's progress in Large Eddy Simulation (LES) in simulating wide variety of flows, statistical models are widely used for the simulations of practical flows of the industry. Nevertheless it is necessary to develop, analyze and optimize these models. The present work devotes to the development and analysis of advanced models for RANS. These models can predict the effects of non-equilibrium turbulent flows with heat and scalar transfer satisfactorily. The parts of the model are ba...

  20. An Explicit Structural Model of Root Hair and Soil Interactions Parameterised by Synchrotron X-ray Computed Tomography.

    Science.gov (United States)

    Keyes, Samuel David; Zygalakis, Konstantinos C; Roose, Tiina

    2017-12-01

    The rhizosphere is a zone of fundamental importance for understanding the dynamics of nutrient acquisition by plant roots. The canonical difficulty of experimentally investigating the rhizosphere led long ago to the adoption of mathematical models, the most sophisticated of which now incorporate explicit representations of root hairs and rhizosphere soil. Mathematical upscaling regimes, such as homogenisation, offer the possibility of incorporating into larger-scale models the important mechanistic processes occurring at the rhizosphere scale. However, we lack concrete descriptions of all the features required to fully parameterise models at the rhizosphere scale. By combining synchrotron X-ray computed tomography (SRXCT) and a novel root growth assay, we derive a three-dimensional description of rhizosphere soil structure suitable for use in multi-scale modelling frameworks. We describe an approach to mitigate sub-optimal root hair detection via structural root hair growth modelling. The growth model is explicitly parameterised with SRXCT data and simulates three-dimensional root hair ideotypes in silico, which are suitable for both ideotypic analysis and parameterisation of 3D geometry in mathematical models. The study considers different hypothetical conditions governing root hair interactions with soil matrices, with their respective effects on hair morphology being compared between idealised and image-derived soil/root geometries. The studies in idealised geometries suggest that packing arrangement of soil affects hair tortuosity more than the particle diameter. Results in field-derived soil suggest that hair access to poorly mobile nutrients is particularly sensitive to the physical interaction between the growing hairs and the phase of the soil in which soil water is present (i.e. the hydrated textural phase). The general trends in fluid-coincident hair length with distance from the root, and their dependence on hair/soil interaction mechanisms, are

  1. System level modelling with open source tools

    DEFF Research Database (Denmark)

    Jakobsen, Mikkel Koefoed; Madsen, Jan; Niaki, Seyed Hosein Attarzadeh

    , called ForSyDe. ForSyDe is available under the open Source approach, which allows small and medium enterprises (SME) to get easy access to advanced modeling capabilities and tools. We give an introduction to the design methodology through the system level modeling of a simple industrial use case, and we...

  2. The european Trans-Tools transport model

    NARCIS (Netherlands)

    Rooijen, T. van; Burgess, A.

    2008-01-01

    The paper presents the use of ArcGIS in the Transtools Transport Model, TRANS-TOOLS, created by an international consortium for the European Commission. The model describe passenger as well as freight transport in Europe with all medium and long distance modes (cars, vans, trucks, train, inland

  3. The Explicit Wake Parametrisation V1.0: a wind farm parametrisation in the mesoscale model WRF

    Directory of Open Access Journals (Sweden)

    P. J. H. Volker

    2015-11-01

    Full Text Available We describe the theoretical basis, implementation, and validation of a new parametrisation that accounts for the effect of large offshore wind farms on the atmosphere and can be used in mesoscale and large-scale atmospheric models. This new parametrisation, referred to as the Explicit Wake Parametrisation (EWP, uses classical wake theory to describe the unresolved wake expansion. The EWP scheme is validated for a neutral atmospheric boundary layer against filtered in situ measurements from two meteorological masts situated a few kilometres away from the Danish offshore wind farm Horns Rev I. The simulated velocity deficit in the wake of the wind farm compares well to that observed in the measurements, and the velocity profile is qualitatively similar to that simulated with large eddy simulation models and from wind tunnel studies. At the same time, the validation process highlights the challenges in verifying such models with real observations.

  4. Vertical Electronic Excitations in Solution with the EOM-CCSD Method Combined with a Polarizable Explicit/Implicit Solvent Model.

    Science.gov (United States)

    Caricato, Marco; Lipparini, Filippo; Scalmani, Giovanni; Cappelli, Chiara; Barone, Vincenzo

    2013-07-09

    The accurate calculation of electronic transition energies and properties of isolated chromophores is not sufficient to provide a realistic simulation of their excited states in solution. In fact, the solvent influences the solute geometry, electronic structure, and response to external fields. Therefore, a proper description of the solvent effect is fundamental. This can be achieved by combining polarizable explicit and implicit representations of the solvent. The former provides a realistic description of solvent molecules around the solute, while the latter introduces the electrostatic effect of the bulk solution and reduces the need of too large a number of explicit solvent molecules. This strategy is particularly appealing when an accurate method such as equation of motion coupled cluster singles and doubles (EOM-CCSD) is employed for the treatment of the chromophore. In this contribution, we present the coupling of EOM-CCSD with a fluctuating charges (FQ) model and polarizable continuum model (PCM) of solvation for vertical excitations in a state-specific framework. The theory, implementation, and prototypical applications of the method are presented. Numerical tests on small solute-water clusters show very good agreement between full EOM-CCSD and EOM-CCSD-FQ calculations, with and without PCM, with differences ≤ 0.1 eV. Additionally, approximated schemes that further reduce the computational cost of the method are introduced and showed to perform well compared to the full method (errors ≤ 0.1 eV).

  5. Explicit modeling of organic chemistry and secondary organic aerosol partitioning for Mexico City and its outflow plume

    Directory of Open Access Journals (Sweden)

    J. Lee-Taylor

    2011-12-01

    Full Text Available The evolution of organic aerosols (OA in Mexico City and its outflow is investigated with the nearly explicit gas phase photochemistry model GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere, wherein precursor hydrocarbons are oxidized to numerous intermediate species for which vapor pressures are computed and used to determine gas/particle partitioning in a chemical box model. Precursor emissions included observed C3-10 alkanes, alkenes, and light aromatics, as well as larger n-alkanes (up to C25 not directly observed but estimated by scaling to particulate emissions according to their volatility. Conditions were selected for comparison with observations made in March 2006 (MILAGRO. The model successfully reproduces the magnitude and diurnal shape for both primary (POA and secondary (SOA organic aerosols, with POA peaking in the early morning at 15–20 μg m−3, and SOA peaking at 10–15 μg m−3 during mid-day. The majority (≥75% of the model SOA stems from reaction products of the large n-alkanes, used here as surrogates for all emitted hydrocarbons of similar volatility, with the remaining SOA originating mostly from the light aromatics. Simulated OA elemental composition reproduces observed H/C and O/C ratios reasonably well, although modeled ratios develop more slowly than observations suggest. SOA chemical composition is initially dominated by δ-hydroxy ketones and nitrates from the large alkanes, with contributions from peroxy acyl nitrates and, at later times when NOx is lower, organic hydroperoxides. The simulated plume-integrated OA mass continues to increase for several days downwind despite dilution-induced particle evaporation, since oxidation chemistry leading to SOA formation remains strong. In this model, the plume SOA burden several days downwind exceeds that leaving the city by a factor of >3. These results suggest significant regional radiative

  6. Explicit modeling of organic chemistry and secondary organic aerosol partitioning for Mexico City and its outflow plume

    Energy Technology Data Exchange (ETDEWEB)

    Lee-Taylor, J.; Madronich, Sasha; Aumont, B.; Baker, A.; Camredon, M.; Hodzic, Alma; Tyndall, G. S.; Apel, Eric; Zaveri, Rahul A.

    2011-12-21

    The evolution of organic aerosols (OA) in Mexico City and its outflow is investigated with the nearly explicit gas phase photochemistry model GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere), wherein precursor hydrocarbons are oxidized to numerous intermediate species for which vapor pressures are computed and used to determine gas/particle partitioning in a chemical box model. Precursor emissions included observed C3-10 alkanes, alkenes, and light aromatics, as well as larger n-alkanes (up to C25) not directly observed but estimated by scaling to particulate emissions according to their volatility. Conditions were selected for comparison with observations made in March 2006 (MILAGRO). The model successfully reproduces the magnitude and diurnal shape for both primary (POA) and secondary (SOA) organic aerosols, with POA peaking in the early morning at 15-20 ug m-3, and SOA peaking at 10-15 μg m-3 during mid-day. The majority (> 75%) of the model SOA stems from the large n-alkanes, with the remainder mostly from the light aromatics. Simulated OA elemental composition reproduces observed H/C and O/C ratios reasonably well, although modeled ratios develop more slowly than observations suggest. SOA chemical composition is initially dominated by *- hydroxy ketones and nitrates from the large alkanes, with contributions from peroxy acyl nitrates and, at later times when NOx is lower, organic hydroperoxides. The simulated plume-integrated OA mass continues to increase for several days downwind despite dilution-induced particle evaporation, since oxidation chemistry leading to SOA formation remains strong. In this model, the plume SOA burden several days downwind exceeds that leaving the city by a factor of >3. These results suggest significant regional radiative impacts of SOA.

  7. A Regional Model for Malaria Vector Developmental Habitats Evaluated Using Explicit, Pond-Resolving Surface Hydrology Simulations.

    Science.gov (United States)

    Asare, Ernest Ohene; Tompkins, Adrian Mark; Bomblies, Arne

    2016-01-01

    Dynamical malaria models can relate precipitation to the availability of vector breeding sites using simple models of surface hydrology. Here, a revised scheme is developed for the VECTRI malaria model, which is evaluated alongside the default scheme using a two year simulation by HYDREMATS, a 10 metre resolution, village-scale model that explicitly simulates individual ponds. Despite the simplicity of the two VECTRI surface hydrology parametrization schemes, they can reproduce the sub-seasonal evolution of fractional water coverage. Calibration of the model parameters is required to simulate the mean pond fraction correctly. The default VECTRI model tended to overestimate water fraction in periods subject to light rainfall events and underestimate it during periods of intense rainfall. This systematic error was improved in the revised scheme by including the a parametrization for surface run-off, such that light rainfall below the initial abstraction threshold does not contribute to ponds. After calibration of the pond model, the VECTRI model was able to simulate vector densities that compared well to the detailed agent based model contained in HYDREMATS without further parameter adjustment. Substituting local rain-gauge data with satellite-retrieved precipitation gave a reasonable approximation, raising the prospects for regional malaria simulations even in data sparse regions. However, further improvements could be made if a method can be derived to calibrate the key hydrology parameters of the pond model in each grid cell location, possibly also incorporating slope and soil texture.

  8. Assessment of the GECKO-A Modeling Tool and Simplified 3D Model Parameterizations for SOA Formation

    Science.gov (United States)

    Aumont, B.; Hodzic, A.; La, S.; Camredon, M.; Lannuque, V.; Lee-Taylor, J. M.; Madronich, S.

    2014-12-01

    Explicit chemical mechanisms aim to embody the current knowledge of the transformations occurring in the atmosphere during the oxidation of organic matter. These explicit mechanisms are therefore useful tools to explore the fate of organic matter during its tropospheric oxidation and examine how these chemical processes shape the composition and properties of the gaseous and the condensed phases. Furthermore, explicit mechanisms provide powerful benchmarks to design and assess simplified parameterizations to be included 3D model. Nevertheless, the explicit mechanism describing the oxidation of hydrocarbons with backbones larger than few carbon atoms involves millions of secondary organic compounds, far exceeding the size of chemical mechanisms that can be written manually. Data processing tools can however be designed to overcome these difficulties and automatically generate consistent and comprehensive chemical mechanisms on a systematic basis. The Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) has been developed for the automatic writing of explicit chemical schemes of organic species and their partitioning between the gas and condensed phases. GECKO-A can be viewed as an expert system that mimics the steps by which chemists might develop chemical schemes. GECKO-A generates chemical schemes according to a prescribed protocol assigning reaction pathways and kinetics data on the basis of experimental data and structure-activity relationships. In its current version, GECKO-A can generate the full atmospheric oxidation scheme for most linear, branched and cyclic precursors, including alkanes and alkenes up to C25. Assessments of the GECKO-A modeling tool based on chamber SOA observations will be presented. GECKO-A was recently used to design a parameterization for SOA formation based on a Volatility Basis Set (VBS) approach. First results will be presented.

  9. Flood vulnerability assessment of residential buildings by explicit damage process modelling

    DEFF Research Database (Denmark)

    Custer, Rocco; Nishijima, Kazuyoshi

    2015-01-01

    contact. Damage processes are modelled at a building component level, utilising engineering models where possible. The modelling approach is presented in general terms, which should be applicable to a large variety of building types. The paper illustrates the implementation of the approach for a 2-storey...... masonry building. Results are presented in terms of a parameter study for several building parameters and hazard characteristics, as well as, in terms of a comparison with damage data and literature vulnerability models. The parameter study indicates that hazard characteristics and building...

  10. Improved fitting of solution X-ray scattering data to macromolecular structures and structural ensembles by explicit water modeling.

    Science.gov (United States)

    Grishaev, Alexander; Guo, Liang; Irving, Thomas; Bax, Ad

    2010-11-10

    A new procedure, AXES, is introduced for fitting small-angle X-ray scattering (SAXS) data to macromolecular structures and ensembles of structures. By using explicit water models to account for the effect of solvent, and by restricting the adjustable fitting parameters to those that dominate experimental uncertainties, including sample/buffer rescaling, detector dark current, and, within a narrow range, hydration layer density, superior fits between experimental high resolution structures and SAXS data are obtained. AXES results are found to be more discriminating than standard Crysol fitting of SAXS data when evaluating poorly or incorrectly modeled protein structures. AXES results for ensembles of structures previously generated for ubiquitin show improved fits over fitting of the individual members of these ensembles, indicating these ensembles capture the dynamic behavior of proteins in solution.

  11. Spatially explicit West Nile virus risk modeling in Santa Clara County, California

    Science.gov (United States)

    A previously created Geographic Information Systems model designed to identify regions of West Nile virus (WNV) transmission risk is tested and calibrated in Santa Clara County, California. American Crows that died from WNV infection in 2005 provide the spatial and temporal ground truth. Model param...

  12. Aggregate and Individual Replication Probability within an Explicit Model of the Research Process

    Science.gov (United States)

    Miller, Jeff; Schwarz, Wolf

    2011-01-01

    We study a model of the research process in which the true effect size, the replication jitter due to changes in experimental procedure, and the statistical error of effect size measurement are all normally distributed random variables. Within this model, we analyze the probability of successfully replicating an initial experimental result by…

  13. Explicit representation and parametrised impacts of under ice shelf seas in the z∗ coordinate ocean model NEMO 3.6

    Directory of Open Access Journals (Sweden)

    P. Mathiot

    2017-07-01

    Full Text Available Ice-shelf–ocean interactions are a major source of freshwater on the Antarctic continental shelf and have a strong impact on ocean properties, ocean circulation and sea ice. However, climate models based on the ocean–sea ice model NEMO (Nucleus for European Modelling of the Ocean currently do not include these interactions in any detail. The capability of explicitly simulating the circulation beneath ice shelves is introduced in the non-linear free surface model NEMO. Its implementation into the NEMO framework and its assessment in an idealised and realistic circum-Antarctic configuration is described in this study. Compared with the current prescription of ice shelf melting (i.e. at the surface, inclusion of open sub-ice-shelf cavities leads to a decrease in sea ice thickness along the coast, a weakening of the ocean stratification on the shelf, a decrease in salinity of high-salinity shelf water on the Ross and Weddell sea shelves and an increase in the strength of the gyres that circulate within the over-deepened basins on the West Antarctic continental shelf. Mimicking the overturning circulation under the ice shelves by introducing a prescribed meltwater flux over the depth range of the ice shelf base, rather than at the surface, is also assessed. It yields similar improvements in the simulated ocean properties and circulation over the Antarctic continental shelf to those from the explicit ice shelf cavity representation. With the ice shelf cavities opened, the widely used three equation ice shelf melting formulation, which enables an interactive computation of melting, is tested. Comparison with observational estimates of ice shelf melting indicates realistic results for most ice shelves. However, melting rates for the Amery, Getz and George VI ice shelves are considerably overestimated.

  14. A spatially explicit model of functional connectivity for the endangered Przewalski's gazelle (Procapra przewalskii in a patchy landscape.

    Directory of Open Access Journals (Sweden)

    Chunlin Li

    Full Text Available BACKGROUND: Habitat fragmentation, associated with human population expansion, impedes dispersal, reduces gene flow and aggravates inbreeding in species on the brink of extinction. Both scientific and conservation communities increasingly realize that maintaining and restoring landscape connectivity is of vital importance in biodiversity conservation. Prior to any conservation initiatives, it is helpful to present conservation practitioners with a spatially explicit model of functional connectivity for the target species or landscape. METHODOLOGY/PRINCIPAL FINDINGS: Using Przewalski's gazelle (Procapra przewalskii as a model of endangered ungulate species in highly fragmented landscape, we present a model providing spatially explicit information to inform the long-term preservation of well-connected metapopulations. We employed a Geographic Information System (GIS and expert-literature method to create a habitat suitability map, to identify potential habitats and to delineate a functional connectivity network (least-cost movement corridors and paths for the gazelle. Results indicated that there were limited suitable habitats for the gazelle, mainly found to the north and northwest of the Qinghai Lake where four of five potential habitat patches were identified. Fifteen pairs of least-cost corridors and paths were mapped connecting eleven extant populations and two neighboring potential patches. The least-cost paths ranged from 0.2 km to 26.8 km in length (averaging 12.4 km and were all longer than corresponding Euclidean distances. CONCLUSIONS/SIGNIFICANCE: The model outputs were validated and supported by the latest findings in landscape genetics of the species, and may provide impetus for connectivity conservation programs. Dispersal barriers were examined and appropriate mitigation strategies were suggested. This study provides conservation practitioners with thorough and visualized information to reserve the landscape connectivity for

  15. Molecular dynamics simulations of proteins: can the explicit water model be varied?

    Energy Technology Data Exchange (ETDEWEB)

    Nutt, David [University of Heidelberg; Smith, Jeremy C [ORNL

    2007-03-01

    In molecular mechanics simulations of biological systems, the solvation water is typically represented by a default water model which is an integral part of the force field. Indeed, protein nonbonding parameters are chosen in order to obtain a balance between water-water and protein-water interactions and hence a reliable description of protein solvation. However, less attention has been paid to the question of whether the water model provides a reliable description of the water properties under the chosen simulation conditions, for which more accurate water models often exist. Here we consider the case of the CHARMM protein force field, which was parameterized for use with a modified TIP3P model. Using quantum mechanical and molecular mechanical calculations, we investigate whether the CHARMM force field can be used with other water models: TIP4P and TIP5P. Solvation properties of N-methylacetamide (NMA), other small solute molecules, and a small protein are examined. The results indicate differences in binding energies and minimum energy geometries, especially for TIP5P, but the overall description of solvation is found to be similar for all models tested. The results provide an indication that molecular mechanics simulations with the CHARMM force field can be performed with water models other than TIP3P, thus enabling an improved description of the solvent water properties.

  16. Molecular Dynamics Simulations of Proteins: Can the Explicit Water Model Be Varied?

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jeremy C [ORNL; Nutt, David [University of Heidelberg

    2007-01-01

    In molecular mechanics simulations of biological systems, the solvation water is typically represented by a default water model which is an integral part of the force field. Indeed, protein nonbonding parameters are chosen in order to obtain a balance between water-water and protein-water interactions and hence a reliable description of protein solvation. However, less attention has been paid to the question of whether the water model provides a reliable description of the water properties under the chosen simulation conditions, for which more accurate water models often exist. Here we consider the case of the CHARMM protein force field, which was parameterized for use with a modified TIP3P model. Using quantum mechanical and molecular mechanical calculations, we investigate whether the CHARMM force field can be used with other water models: TIP4P and TIP5P. Solvation properties of N-methylacetamide (NMA), other small solute molecules, and a small protein are examined. The results indicate differences in binding energies and minimum energy geometries, especially for TIP5P, but the overall description of solvation is found to be similar for all models tested. The results provide an indication that molecular mechanics simulations with the CHARMM force field can be performed with water models other than TIP3P, thus enabling an improved description of the solvent water properties.

  17. An open and extensible framework for spatially explicit land use change modelling: the lulcc R package

    Science.gov (United States)

    Moulds, S.; Buytaert, W.; Mijic, A.

    2015-10-01

    We present the lulcc software package, an object-oriented framework for land use change modelling written in the R programming language. The contribution of the work is to resolve the following limitations associated with the current land use change modelling paradigm: (1) the source code for model implementations is frequently unavailable, severely compromising the reproducibility of scientific results and making it impossible for members of the community to improve or adapt models for their own purposes; (2) ensemble experiments to capture model structural uncertainty are difficult because of fundamental differences between implementations of alternative models; and (3) additional software is required because existing applications frequently perform only the spatial allocation of change. The package includes a stochastic ordered allocation procedure as well as an implementation of the CLUE-S algorithm. We demonstrate its functionality by simulating land use change at the Plum Island Ecosystems site, using a data set included with the package. It is envisaged that lulcc will enable future model development and comparison within an open environment.

  18. BETR Global - A geographically explicit global-scale multimedia contaminant fate model

    Energy Technology Data Exchange (ETDEWEB)

    Macleod, M.; Waldow, H. von; Tay, P.; Armitage, J. M.; Wohrnschimmel, H.; Riley, W.; McKone, T. E.; Hungerbuhler, K.

    2011-04-01

    We present two new software implementations of the BETR Global multimedia contaminant fate model. The model uses steady-state or non-steady-state mass-balance calculations to describe the fate and transport of persistent organic pollutants using a desktop computer. The global environment is described using a database of long-term average monthly conditions on a 15{sup o} x 15{sup o} grid. We demonstrate BETR Global by modeling the global sources, transport, and removal of decamethylcyclopentasiloxane (D5).

  19. Using Satellite Remote Sensing Data in a Spatially Explicit Price Model

    Science.gov (United States)

    Brown, Molly E.; Pinzon, Jorge E.; Prince, Stephen D.

    2007-01-01

    Famine early warning organizations use data from multiple disciplines to assess food insecurity of communities and regions in less-developed parts of the World. In this paper we integrate several indicators that are available to enhance the information for preparation for and responses to food security emergencies. The assessment uses a price model based on the relationship between the suitability of the growing season and market prices for coarse grain. The model is then used to create spatially continuous maps of millet prices. The model is applied to the dry central and northern areas of West Africa, using satellite-derived vegetation indices for the entire region. By coupling the model with vegetation data estimated for one to four months into the future, maps are created of a leading indicator of potential price movements. It is anticipated that these maps can be used to enable early warning of famine and for planning appropriate responses.

  20. Deterministic Compilation of Temporal Safety Properties in Explicit State Model Checking

    Data.gov (United States)

    National Aeronautics and Space Administration — The translation of temporal logic specifications constitutes an essen- tial step in model checking and a major influence on the efficiency of formal verification via...

  1. Implicit-Explicit Formulations of a Three-Dimensional Nonhydrostatic Unified Model of the Atmosphere (NUMA)

    Science.gov (United States)

    2013-01-01

    ratio between the horizontal and vertical directions as follows RGR = HGR VGR . For the Cloud -Resolving Mode ( CRM ) simulations of the thermal bubble, RGR...CONSTANTINESCU ‡ Key words. cloud -resolving model; compressible flow; element-based Galerkin methods; Euler; global model; IMEX; Lagrange; Legendre...various nonhydrostatic flow regimes, including cloud -resolving and mesoscale (flow in a 3D Cartesian domain) as well as global regimes (flow in spherical

  2. An explicit SU(12) family and flavor unification model with natural fermion masses and mixings

    Energy Technology Data Exchange (ETDEWEB)

    Albright, Carl H. [Northern Illinois Univ., Dekalb, IL (United States); Feger, Robert P. [Vanderbilt Univ., Nashville, TN (United States); Kephart, Thomas W. [Vanderbilt Univ., Nashville, TN (United States)

    2012-07-01

    We present an SU(12) unification model with three light chiral families, avoiding any external flavor symmetries. The hierarchy of quark and lepton masses and mixings is explained by higher dimensional Yukawa interactions involving Higgs bosons that contain SU(5) singlet fields with VEVs about 50 times smaller than the SU(12) unification scale. The presented model has been analyzed in detail and found to be in very good agreement with the observed quark and lepton masses and mixings.

  3. A spatially explicit suspended-sediment load model for western Oregon

    Science.gov (United States)

    Wise, Daniel R.; O'Connor, Jim

    2016-06-27

    We calibrated the watershed model SPARROW (Spatially Referenced Regressions on Watershed attributes) to give estimates of suspended-sediment loads for western Oregon and parts of northwestern California. Estimates of suspended-sediment loads were derived from a nonlinear least squares regression that related explanatory variables representing landscape and transport conditions to measured suspended-sediment loads at 68 measurement stations. The model gives estimates of model coefficients and their uncertainty within a spatial framework defined by the National Hydrography Dataset Plus hydrologic network. The resulting model explained 64 percent of the variability in suspended-sediment yield and had a root mean squared error value of 0.737. The predictor variables selected for the final model were (1) generalized lithologic province, (2) mean annual precipitation, and (3) burned area (by recent wildfire). Other landscape characteristics also were considered, but they were not significant predictors of sediment transport, were strongly correlated with another predictor variable, or were not as significant as the predictors selected for the final model.

  4. Impact of chamber wall loss of gaseous organic compounds on secondary organic aerosol formation: explicit modeling of SOA formation from alkane and alkene oxidation

    Directory of Open Access Journals (Sweden)

    Y. S. La

    2016-02-01

    Full Text Available Recent studies have shown that low volatility gas-phase species can be lost onto the smog chamber wall surfaces. Although this loss of organic vapors to walls could be substantial during experiments, its effect on secondary organic aerosol (SOA formation has not been well characterized and quantified yet. Here the potential impact of chamber walls on the loss of gaseous organic species and SOA formation has been explored using the Generator for Explicit Chemistry and Kinetics of the Organics in the Atmosphere (GECKO-A modeling tool, which explicitly represents SOA formation and gas–wall partitioning. The model was compared with 41 smog chamber experiments of SOA formation under OH oxidation of alkane and alkene series (linear, cyclic and C12-branched alkanes and terminal, internal and 2-methyl alkenes with 7 to 17 carbon atoms under high NOx conditions. Simulated trends match observed trends within and between homologous series. The loss of organic vapors to the chamber walls is found to affect SOA yields as well as the composition of the gas and the particle phases. Simulated distributions of the species in various phases suggest that nitrates, hydroxynitrates and carbonylesters could substantially be lost onto walls. The extent of this process depends on the rate of gas–wall mass transfer, the vapor pressure of the species and the duration of the experiments. This work suggests that SOA yields inferred from chamber experiments could be underestimated up a factor of 2 due to the loss of organic vapors to chamber walls.

  5. A Spatio-Temporally Explicit Random Encounter Model for Large-Scale Population Surveys.

    Directory of Open Access Journals (Sweden)

    Jussi Jousimo

    Full Text Available Random encounter models can be used to estimate population abundance from indirect data collected by non-invasive sampling methods, such as track counts or camera-trap data. The classical Formozov-Malyshev-Pereleshin (FMP estimator converts track counts into an estimate of mean population density, assuming that data on the daily movement distances of the animals are available. We utilize generalized linear models with spatio-temporal error structures to extend the FMP estimator into a flexible Bayesian modelling approach that estimates not only total population size, but also spatio-temporal variation in population density. We also introduce a weighting scheme to estimate density on habitats that are not covered by survey transects, assuming that movement data on a subset of individuals is available. We test the performance of spatio-temporal and temporal approaches by a simulation study mimicking the Finnish winter track count survey. The results illustrate how the spatio-temporal modelling approach is able to borrow information from observations made on neighboring locations and times when estimating population density, and that spatio-temporal and temporal smoothing models can provide improved estimates of total population size compared to the FMP method.

  6. Progress toward an explicit mechanistic model for the light-driven pump, bacteriorhodopsin

    Science.gov (United States)

    Lanyi, J. K.

    1999-01-01

    Recent crystallographic information about the structure of bacteriorhodopsin and some of its photointermediates, together with a large amount of spectroscopic and mutational data, suggest a mechanistic model for how this protein couples light energy to the translocation of protons across the membrane. Now nearing completion, this detailed molecular model will describe the nature of the steric and electrostatic conflicts at the photoisomerized retinal, as well as the means by which it induces proton transfers in the two half-channels leading to the two membrane surfaces, thereby causing unidirectional, uphill transport.

  7. HYDROLOGICAL PROCESSES MODELLING USING ADVANCED HYDROINFORMATIC TOOLS

    Directory of Open Access Journals (Sweden)

    BEILICCI ERIKA

    2014-03-01

    Full Text Available The water has an essential role in the functioning of ecosystems by integrating the complex physical, chemical, and biological processes that sustain life. Water is a key factor in determining the productivity of ecosystems, biodiversity and species composition. Water is also essential for humanity: water supply systems for population, agriculture, fisheries, industries, and hydroelectric power depend on water supplies. The modelling of hydrological processes is an important activity for water resources management, especially now, when the climate change is one of the major challenges of our century, with strong influence on hydrological processes dynamics. Climate change and needs for more knowledge in water resources require the use of advanced hydroinformatic tools in hydrological processes modelling. The rationale and purpose of advanced hydroinformatic tools is to develop a new relationship between the stakeholders and the users and suppliers of the systems: to offer the basis (systems which supply useable results, the validity of which cannot be put in reasonable doubt by any of the stakeholders involved. For a successful modelling of hydrological processes also need specialists well trained and able to use advanced hydro-informatics tools. Results of modelling can be a useful tool for decision makers to taking efficient measures in social, economical and ecological domain regarding water resources, for an integrated water resources management.

  8. The “Destabilizing” Effect of Cannibalism in a Spatially Explicit Three-Species Age Structured Predator-Prey Model

    Directory of Open Access Journals (Sweden)

    Aladeen Al Basheer

    2017-01-01

    Full Text Available Cannibalism, the act of killing and consumption of conspecifics, is generally considered to be a stabilising process in ODE models of predator-prey systems. On the other hand, Sun et al. were the first to show that cannibalism can cause Turing instability, in the classical Rosenzweig-McArthur two-species PDE model, which is an impossibility without cannibalism. Magnússon’s classic work is the first to show that cannibalism in a structured three-species predator-prey ODE model can actually be destabilising. In the current manuscript we consider the PDE form of the three-species model proposed in Magnússon’s classic work. We prove that, in the absence of cannibalism, Turing instability is an impossibility in this model, for any range of parameters. However, the inclusion of cannibalism can cause Turing instability. Thus, to the best of our knowledge, we report the first cannibalism induced Turing instability result, in spatially explicit three-species age structured predator-prey systems. We also show that, in the classical ODE model proposed by Magnússon, cannibalism can act as a life boat mechanism, for the prey.

  9. Spatially explicit modeling of mixed-severity fire regimes and landscape dynamics

    Science.gov (United States)

    Michael C. Wimberly; Rebecca S.H. Kennedy

    2008-01-01

    Simulation models of disturbance and succession are being increasingly applied to characterize landscape composition and dynamics under natural fire regimes, and to evaluate alternative management strategies for ecological restoration and fire hazard reduction. However, we have a limited understanding of how landscapes respond to changes in fire frequency, and about...

  10. An explicit statistical model of learning lexical segmentation using multiple cues

    NARCIS (Netherlands)

    Çöltekin, Ça ̆grı; Nerbonne, John; Lenci, Alessandro; Padró, Muntsa; Poibeau, Thierry; Villavicencio, Aline

    2014-01-01

    This paper presents an unsupervised and incremental model of learning segmentation that combines multiple cues whose use by children and adults were attested by experimental studies. The cues we exploit in this study are predictability statistics, phonotactics, lexical stress and partial lexical

  11. Spatially Explicit West Nile Virus Risk Modeling in Santa Clara County, CA

    Science.gov (United States)

    A geographic information systems model designed to identify regions of West Nile virus (WNV) transmission risk was tested and calibrated with data collected in Santa Clara County, California. American Crows that died from WNV infection in 2005, provided spatial and temporal ground truth. When the mo...

  12. Modelling explicit tides in the Indonesian seas: An important process for surface sea water properties.

    Science.gov (United States)

    Nugroho, Dwiyoga; Koch-Larrouy, Ariane; Gaspar, Philippe; Lyard, Florent; Reffray, Guillaume; Tranchant, Benoit

    2017-06-16

    Very intense internal tides take place in Indonesian seas. They dissipate and affect the vertical distribution of temperature and currents, which in turn influence the survival rates and transports of most planktonic organisms at the base of the whole marine ecosystem. This study uses the INDESO physical model to characterize the internal tides spatio-temporal patterns in the Indonesian Seas. The model reproduced internal tide dissipation in agreement with previous fine structure and microstructure observed in-situ in the sites of generation. The model also produced similar water mass transformation as the previous parameterization of Koch-Larrouy et al. (2007), and show good agreement with observations. The resulting cooling at the surface is 0.3°C, with maxima of 0.8°C at the location of internal tides energy, with stronger cooling in austral winter. The cycle of spring tides and neap tides modulates this impact by 0.1°C to 0.3°C. These results suggest that mixing due to internal tides might also upwell nutrients at the surface at a frequency similar to the tidal frequencies. Implications for biogeochemical modelling are important. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. A Stabilized Scale-Similarity Model for Explicitly-Filtered LES

    Science.gov (United States)

    Edoh, Ayaboe; Karagozian, Ann; Sankaran, Venkateswaran

    2016-11-01

    Accurate simulation of the filtered-scales in LES is affected by the competing presence of modeling and discretization errors. In order to properly assess modeling techniques, it is imperative to minimize the influence of the numerical scheme. The current investigation considers the inclusion of resolved and un-resolved sub-filter stress ([U]RSFS) components in the governing equations, which is suggestive of a mixed-model approach. Taylor-series expansions of discrete filter stencils are used to inform proper scaling of a Scale-Similarity model representation of the RSFS term, and accompanying stabilization is provided by tunable and scale-discriminant filter-based artificial dissipation techniques that represent the URSFS term implicitly. Effective removal of numerical error from the LES solution is studied with respect to the 1D Burgers equation with synthetic turbulence, and extension to 3D Navier-Stokes system computations is motivated. Distribution A: Approved for public release, distribution unlimited. Supported by AFOSR (PMs: Drs. Chiping Li and Michael Kendra).

  14. Temporal lobe epilepsy as a model to understand human memory: the distinction between explicit and implicit memory.

    Science.gov (United States)

    Leritz, Elizabeth C; Grande, Laura J; Bauer, Russell M

    2006-08-01

    Decades of research have provided substantial evidence of memory impairments in patients with temporal lobe epilepsy (TLE), including deficits in the encoding, storage, and retrieval of new information. These findings are not surprising, given the associated underlying neuroanatomy, including the hippocampus and surrounding medial temporal lobe structures. Because of its associated anatomic and cognitive characteristics, TLE has provided an excellent model by which to examine specific aspects of human memory functioning, including classic distinctions such as that between explicit and implicit memory. Various clinical and experimental research studies have supported the idea that both conscious and unconscious processes support memory functioning, but the role of relevant brain structures has been the subject of debate. This review is concerned with a discussion of the current status of this research and, importantly, how TLE can inform future studies of memory distinctions.

  15. Analyzing key constraints to biogas production from crop residues and manure in the EU—A spatially explicit model

    Science.gov (United States)

    Persson, U. Martin

    2017-01-01

    This paper presents a spatially explicit method for making regional estimates of the potential for biogas production from crop residues and manure, accounting for key technical, biochemical, environmental and economic constraints. Methods for making such estimates are important as biofuels from agricultural residues are receiving increasing policy support from the EU and major biogas producers, such as Germany and Italy, in response to concerns over unintended negative environmental and social impacts of conventional biofuels. This analysis comprises a spatially explicit estimate of crop residue and manure production for the EU at 250 m resolution, and a biogas production model accounting for local constraints such as the sustainable removal of residues, transportation of substrates, and the substrates’ biochemical suitability for anaerobic digestion. In our base scenario, the EU biogas production potential from crop residues and manure is about 0.7 EJ/year, nearly double the current EU production of biogas from agricultural substrates, most of which does not come from residues or manure. An extensive sensitivity analysis of the model shows that the potential could easily be 50% higher or lower, depending on the stringency of economic, technical and biochemical constraints. We find that the potential is particularly sensitive to constraints on the substrate mixtures’ carbon-to-nitrogen ratio and dry matter concentration. Hence, the potential to produce biogas from crop residues and manure in the EU depends to large extent on the possibility to overcome the challenges associated with these substrates, either by complementing them with suitable co-substrates (e.g. household waste and energy crops), or through further development of biogas technology (e.g. pretreatment of substrates and recirculation of effluent). PMID:28141827

  16. Analyzing key constraints to biogas production from crop residues and manure in the EU-A spatially explicit model.

    Directory of Open Access Journals (Sweden)

    Rasmus Einarsson

    Full Text Available This paper presents a spatially explicit method for making regional estimates of the potential for biogas production from crop residues and manure, accounting for key technical, biochemical, environmental and economic constraints. Methods for making such estimates are important as biofuels from agricultural residues are receiving increasing policy support from the EU and major biogas producers, such as Germany and Italy, in response to concerns over unintended negative environmental and social impacts of conventional biofuels. This analysis comprises a spatially explicit estimate of crop residue and manure production for the EU at 250 m resolution, and a biogas production model accounting for local constraints such as the sustainable removal of residues, transportation of substrates, and the substrates' biochemical suitability for anaerobic digestion. In our base scenario, the EU biogas production potential from crop residues and manure is about 0.7 EJ/year, nearly double the current EU production of biogas from agricultural substrates, most of which does not come from residues or manure. An extensive sensitivity analysis of the model shows that the potential could easily be 50% higher or lower, depending on the stringency of economic, technical and biochemical constraints. We find that the potential is particularly sensitive to constraints on the substrate mixtures' carbon-to-nitrogen ratio and dry matter concentration. Hence, the potential to produce biogas from crop residues and manure in the EU depends to large extent on the possibility to overcome the challenges associated with these substrates, either by complementing them with suitable co-substrates (e.g. household waste and energy crops, or through further development of biogas technology (e.g. pretreatment of substrates and recirculation of effluent.

  17. Analyzing key constraints to biogas production from crop residues and manure in the EU-A spatially explicit model.

    Science.gov (United States)

    Einarsson, Rasmus; Persson, U Martin

    2017-01-01

    This paper presents a spatially explicit method for making regional estimates of the potential for biogas production from crop residues and manure, accounting for key technical, biochemical, environmental and economic constraints. Methods for making such estimates are important as biofuels from agricultural residues are receiving increasing policy support from the EU and major biogas producers, such as Germany and Italy, in response to concerns over unintended negative environmental and social impacts of conventional biofuels. This analysis comprises a spatially explicit estimate of crop residue and manure production for the EU at 250 m resolution, and a biogas production model accounting for local constraints such as the sustainable removal of residues, transportation of substrates, and the substrates' biochemical suitability for anaerobic digestion. In our base scenario, the EU biogas production potential from crop residues and manure is about 0.7 EJ/year, nearly double the current EU production of biogas from agricultural substrates, most of which does not come from residues or manure. An extensive sensitivity analysis of the model shows that the potential could easily be 50% higher or lower, depending on the stringency of economic, technical and biochemical constraints. We find that the potential is particularly sensitive to constraints on the substrate mixtures' carbon-to-nitrogen ratio and dry matter concentration. Hence, the potential to produce biogas from crop residues and manure in the EU depends to large extent on the possibility to overcome the challenges associated with these substrates, either by complementing them with suitable co-substrates (e.g. household waste and energy crops), or through further development of biogas technology (e.g. pretreatment of substrates and recirculation of effluent).

  18. Individual-Based Spatially-Explicit Model of an Herbivore and Its Resource: The Effect of Habitat Reduction and Fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Kostova, T; Carlsen, T; Kercher, J

    2002-06-17

    We present an individual-based, spatially-explicit model of the dynamics of a small mammal and its resource. The life histories of each individual animal are modeled separately. The individuals can have the status of residents or wanderers and belong to behaviorally differing groups of juveniles or adults and males or females. Their territory defending and monogamous behavior is taken into consideration. The resource, green vegetation, grows depending on seasonal climatic characteristics and is diminished due to the herbivore's grazing. Other specifics such as a varying personal energetic level due to feeding and starvation of the individuals, mating preferences, avoidance of competitors, dispersal of juveniles, as a result of site overgrazing, etc. are included in the model. We determined model parameters from real data for the species Microtus ochrogaster (prairie vole). The simulations are done for a case of an enclosed habitat without predators or other species competitors. The goal of the study is to find the relation between size of habitat and population persistence. The experiments with the model show the populations go extinct due to severe overgrazing, but that the length of population persistence depends on the area of the habitat as well as on the presence of fragmentation. Additionally, the total population size of the vole population obtained during the simulations exhibits yearly fluctuations as well as multi-yearly peaks of fluctuations. This dynamics is similar to the one observed in prairie vole field studies.

  19. Decadal shifts of East Asian summer monsoon in a climate model free of explicit GHGs and aerosols

    Science.gov (United States)

    Lin, Renping; Zhu, Jiang; Zheng, Fei

    2016-12-01

    The East Asian summer monsoon (EASM) experienced decadal transitions over the past few decades, and the associated "wetter-South-drier-North" shifts in rainfall patterns in China significantly affected the social and economic development in China. Two viewpoints stand out to explain these decadal shifts, regarding the shifts either a result of internal variability of climate system or that of external forcings (e.g. greenhouse gases (GHGs) and anthropogenic aerosols). However, most climate models, for example, the Atmospheric Model Intercomparison Project (AMIP)-type simulations and the Coupled Model Intercomparison Project (CMIP)-type simulations, fail to simulate the variation patterns, leaving the mechanisms responsible for these shifts still open to dispute. In this study, we conducted a successful simulation of these decadal transitions in a coupled model where we applied ocean data assimilation in the model free of explicit aerosols and GHGs forcing. The associated decadal shifts of the three-dimensional spatial structure in the 1990s, including the eastward retreat, the northward shift of the western Pacific subtropical high (WPSH), and the south-cool-north-warm pattern of the upper-level tropospheric temperature, were all well captured. Our simulation supports the argument that the variations of the oceanic fields are the dominant factor responsible for the EASM decadal transitions.

  20. Web tools for predictive toxicology model building.

    Science.gov (United States)

    Jeliazkova, Nina

    2012-07-01

    The development and use of web tools in chemistry has accumulated more than 15 years of history already. Powered by the advances in the Internet technologies, the current generation of web systems are starting to expand into areas, traditional for desktop applications. The web platforms integrate data storage, cheminformatics and data analysis tools. The ease of use and the collaborative potential of the web is compelling, despite the challenges. The topic of this review is a set of recently published web tools that facilitate predictive toxicology model building. The focus is on software platforms, offering web access to chemical structure-based methods, although some of the frameworks could also provide bioinformatics or hybrid data analysis functionalities. A number of historical and current developments are cited. In order to provide comparable assessment, the following characteristics are considered: support for workflows, descriptor calculations, visualization, modeling algorithms, data management and data sharing capabilities, availability of GUI or programmatic access and implementation details. The success of the Web is largely due to its highly decentralized, yet sufficiently interoperable model for information access. The expected future convergence between cheminformatics and bioinformatics databases provides new challenges toward management and analysis of large data sets. The web tools in predictive toxicology will likely continue to evolve toward the right mix of flexibility, performance, scalability, interoperability, sets of unique features offered, friendly user interfaces, programmatic access for advanced users, platform independence, results reproducibility, curation and crowdsourcing utilities, collaborative sharing and secure access.

  1. Simulation of semi-explicit mechanisms of SOA formation from glyoxal in a 3D model

    Science.gov (United States)

    Knote, C. J.; Hodzic, A.; Jimenez, J. L.; Volkamer, R.; Orlando, J. J.; Baidar, S.; Brioude, J. F.; Fast, J. D.; Gentner, D. R.; Goldstein, A. H.; Hayes, P. L.; Knighton, W. B.; Oetjen, H.; Setyan, A.; Stark, H.; Thalman, R. M.; Tyndall, G. S.; Washenfelder, R. A.; Waxman, E.; Zhang, Q.

    2013-12-01

    Formation of secondary organic aerosols (SOA) through multi-phase processing of glyoxal has been proposed recently as a relevant contributor to SOA mass. Glyoxal has both anthropogenic and biogenic sources, and readily partitions into the aqueous-phase of cloud droplets and aerosols. Both reversible and irreversible chemistry in the liquid-phase has been observed. A recent laboratory study indicates that the presence of salts in the liquid-phase strongly enhances the Henry';s law constant of glyoxal, allowing for much more effective multi-phase processing. In our work we investigate the contribution of glyoxal to SOA formation on the regional scale. We employ the regional chemistry transport model WRF-chem with MOZART gas-phase chemistry and MOSAIC aerosols, which we both extended to improve the description of glyoxal formation in the gas-phase, and its interactions with aerosols. The detailed description of aerosols in our setup allows us to compare very simple (uptake coefficient) parameterizations of SOA formation from glyoxal, as has been used in previous modeling studies, with much more detailed descriptions of the various pathways postulated based on laboratory studies. Measurements taken during the CARES and CalNex campaigns in California in summer 2010 allowed us to constrain the model, including the major direct precursors of glyoxal. Simulations at convection-permitting resolution over a 2 week period in June 2010 have been conducted to assess the effect of the different ways to parameterize SOA formation from glyoxal and investigate its regional variability. We find that depending on the parameterization used the contribution of glyoxal to SOA is between 1 and 15% in the LA basin during this period, and that simple parameterizations based on uptake coefficients derived from box model studies lead to higher contributions (15%) than parameterizations based on lab experiments (1%). A kinetic limitation found in experiments hinders substantial contribution

  2. Spatially explicit Schistosoma infection risk in eastern Africa using Bayesian geostatistical modelling

    DEFF Research Database (Denmark)

    Schur, Nadine; Hürlimann, Eveline; Stensgaard, Anna-Sofie

    2013-01-01

    surveys on different age-groups and to acquire separate estimates for individuals aged ≤20 years and entire communities. Prevalence estimates were combined with population statistics to obtain country-specific numbers of Schistosoma infections. We estimate that 122 million individuals in eastern Africa...... are currently infected with either S. mansoni, or S. haematobium, or both species concurrently. Country-specific population-adjusted prevalence estimates range between 12.9% (Uganda) and 34.5% (Mozambique) for S. mansoni and between 11.9% (Djibouti) and 40.9% (Mozambique) for S. haematobium. Our models revealed...

  3. Spatially explicit modeling of lesser prairie-chicken lek density in Texas

    Science.gov (United States)

    Timmer, Jennifer M.; Butler, M.J.; Ballard, Warren; Boal, Clint W.; Whitlaw, H.A.

    2014-01-01

    As with many other grassland birds, lesser prairie-chickens (Tympanuchus pallidicinctus) have experienced population declines in the Southern Great Plains. Currently they are proposed for federal protection under the Endangered Species Act. In addition to a history of land-uses that have resulted in habitat loss, lesser prairie-chickens now face a new potential disturbance from energy development. We estimated lek density in the occupied lesser prairie-chicken range of Texas, USA, and modeled anthropogenic and vegetative landscape features associated with lek density. We used an aerial line-transect survey method to count lesser prairie-chicken leks in spring 2010 and 2011 and surveyed 208 randomly selected 51.84-km(2) blocks. We divided each survey block into 12.96-km(2) quadrats and summarized landscape variables within each quadrat. We then used hierarchical distance-sampling models to examine the relationship between lek density and anthropogenic and vegetative landscape features and predict how lek density may change in response to changes on the landscape, such as an increase in energy development. Our best models indicated lek density was related to percent grassland, region (i.e., the northeast or southwest region of the Texas Panhandle), total percentage of grassland and shrubland, paved road density, and active oil and gas well density. Predicted lek density peaked at 0.39leks/12.96km(2) (SE=0.09) and 2.05leks/12.96km(2) (SE=0.56) in the northeast and southwest region of the Texas Panhandle, respectively, which corresponds to approximately 88% and 44% grassland in the northeast and southwest region. Lek density increased with an increase in total percentage of grassland and shrubland and was greatest in areas with lower densities of paved roads and lower densities of active oil and gas wells. We used the 2 most competitive models to predict lek abundance and estimated 236 leks (CV=0.138, 95% CI=177-306leks) for our sampling area. Our results suggest that

  4. A spatially explicit hydro-ecological modeling framework (BEPS-TerrainLab V2.0): Model description and test in a boreal ecosystem in Eastern North America

    Science.gov (United States)

    Govind, Ajit; Chen, Jing Ming; Margolis, Hank; Ju, Weimin; Sonnentag, Oliver; Giasson, Marc-André

    2009-04-01

    SummaryA spatially explicit, process-based hydro-ecological model, BEPS-TerrainLab V2.0, was developed to improve the representation of ecophysiological, hydro-ecological and biogeochemical processes of boreal ecosystems in a tightly coupled manner. Several processes unique to boreal ecosystems were implemented including the sub-surface lateral water fluxes, stratification of vegetation into distinct layers for explicit ecophysiological representation, inclusion of novel spatial upscaling strategies and biogeochemical processes. To account for preferential water fluxes common in humid boreal ecosystems, a novel scheme was introduced based on laboratory analyses. Leaf-scale ecophysiological processes were upscaled to canopy-scale by explicitly considering leaf physiological conditions as affected by light and water stress. The modified model was tested with 2 years of continuous measurements taken at the Eastern Old Black Spruce Site of the Fluxnet-Canada Research Network located in a humid boreal watershed in eastern Canada. Comparison of the simulated and measured ET, water-table depth (WTD), volumetric soil water content (VSWC) and gross primary productivity (GPP) revealed that BEPS-TerrainLab V2.0 simulates hydro-ecological processes with reasonable accuracy. The model was able to explain 83% of the ET, 92% of the GPP variability and 72% of the WTD dynamics. The model suggests that in humid ecosystems such as eastern North American boreal watersheds, topographically driven sub-surface baseflow is the main mechanism of soil water partitioning which significantly affects the local-scale hydrological conditions.

  5. Uncertainty analysis of a spatially-explicit annual water-balance model: case study of the Cape Fear catchment, NC

    Science.gov (United States)

    Hamel, P.; Guswa, A. J.

    2014-10-01

    There is an increasing demand for assessment of water provisioning ecosystem services. While simple models with low data and expertise requirements are attractive, their use as decision-aid tools should be supported by uncertainty characterization. We assessed the performance of the InVEST annual water yield model, a popular tool for ecosystem service assessment based on the Budyko framework. Our study involved the comparison of ten subcatchments in the Cape Fear watershed, NC, ranging in size and land use configuration. We analyzed the model sensitivity to the eco-hydrological parameters and the effect of extrapolating a lumped theory to a fully distributed model. Comparison of the model predictions with observations and with a lumped water balance model confirmed that the model is able to represent differences in land uses. Our results also emphasize the effect of climate input errors, especially annual precipitation, and errors in the eco-hydrological parameter Z, which are both comparable to the model structure uncertainties. In practice, our case study supports the use of the model for predicting land use change effect on water provisioning, although its use for identifying areas of high water yield will be influenced by precipitation errors. While the results are inherently local, analysis of the model structure suggests that many insights from this study will hold globally. Further work toward characterization of uncertainties in such simple models will help identify the regions and decision contexts where the model predictions may be used with confidence.

  6. Animal models: an important tool in mycology.

    Science.gov (United States)

    Capilla, Javier; Clemons, Karl V; Stevens, David A

    2007-12-01

    Animal models of fungal infections are, and will remain, a key tool in the advancement of the medical mycology. Many different types of animal models of fungal infection have been developed, with murine models the most frequently used, for studies of pathogenesis, virulence, immunology, diagnosis, and therapy. The ability to control numerous variables in performing the model allows us to mimic human disease states and quantitatively monitor the course of the disease. However, no single model can answer all questions and different animal species or different routes of infection can show somewhat different results. Thus, the choice of which animal model to use must be made carefully, addressing issues of the type of human disease to mimic, the parameters to follow and collection of the appropriate data to answer those questions being asked. This review addresses a variety of uses for animal models in medical mycology. It focuses on the most clinically important diseases affecting humans and cites various examples of the different types of studies that have been performed. Overall, animal models of fungal infection will continue to be valuable tools in addressing questions concerning fungal infections and contribute to our deeper understanding of how these infections occur, progress and can be controlled and eliminated.

  7. Modeling the fate of nitrogen on the catchment scale using a spatially explicit hydro-biogeochemical simulation system

    Science.gov (United States)

    Klatt, S.; Butterbach-Bahl, K.; Kiese, R.; Haas, E.; Kraus, D.; Molina-Herrera, S. W.; Kraft, P.

    2015-12-01

    The continuous growth of the human population demands an equally growing supply for fresh water and food. As a result, available land for efficient agriculture is constantly diminishing which forces farmers to cultivate inferior croplands and intensify agricultural practices, e.g., increase the use of synthetic fertilizers. This intensification of marginal areas in particular will cause a dangerous rise in nitrate discharge into open waters or even drinking water resources. In order to reduce the amount of nitrate lost by surface runoff or lateral subsurface transport, bufferstrips have proved to be a valuable means. Current laws, however, promote rather static designs (i.e., width and usage) even though a multitude of factors, e.g., soil type, slope, vegetation and the nearby agricultural management, determines its effectiveness. We propose a spatially explicit modeling approach enabling to assess the effects of those factors on nitrate discharge from arable lands using the fully distributed hydrology model CMF coupled to the complex biogeochemical model LandscapeDNDC. Such a modeling scheme allows to observe the displacement of dissolved nutrients in both vertical and horizontal directions and serves to estimate both their uptake by the vegetated bufferstrip and loss to the environment. First results indicate a significant reduction of nitrate loss in the presence of a bufferstrip (2.5 m). We show effects induced by various buffer strip widths and plant cover on the nitrate retention.

  8. An empirical evaluation of camera trapping and spatially explicit capture-recapture models for estimating chimpanzee density.

    Science.gov (United States)

    Després-Einspenner, Marie-Lyne; Howe, Eric J; Drapeau, Pierre; Kühl, Hjalmar S

    2017-07-01

    Empirical validations of survey methods for estimating animal densities are rare, despite the fact that only an application to a population of known density can demonstrate their reliability under field conditions and constraints. Here, we present a field validation of camera trapping in combination with spatially explicit capture-recapture (SECR) methods for enumerating chimpanzee populations. We used 83 camera traps to sample a habituated community of western chimpanzees (Pan troglodytes verus) of known community and territory size in Taï National Park, Ivory Coast, and estimated community size and density using spatially explicit capture-recapture models. We aimed to: (1) validate camera trapping as a means to collect capture-recapture data for chimpanzees; (2) validate SECR methods to estimate chimpanzee density from camera trap data; (3) compare the efficacy of targeting locations frequently visited by chimpanzees versus deploying cameras according to a systematic design; (4) evaluate the performance of SECR estimators with reduced sampling effort; and (5) identify sources of heterogeneity in detection probabilities. Ten months of camera trapping provided abundant capture-recapture data. All weaned individuals were detected, most of them multiple times, at both an array of targeted locations, and a systematic grid of cameras positioned randomly within the study area, though detection probabilities were higher at targeted locations. SECR abundance estimates were accurate and precise, and analyses of subsets of the data indicated that the majority of individuals in a community could be detected with as few as five traps deployed within their territory. Our results highlight the potential of camera trapping for cost-effective monitoring of chimpanzee populations. © 2017 Wiley Periodicals, Inc.

  9. Integrating decision management with UML modeling concepts and tools

    DEFF Research Database (Denmark)

    Könemann, Patrick

    2009-01-01

    . In this paper, we propose an integration of a decision management and a UML-based modeling tool, based on use cases we distill from an example: the UML modeling tool shall show all decisions related to a model and allow extending or updating them; the decision management tool shall trigger the modeling tool...

  10. Modeling two-phase flow of immiscible fluids in porous media: Buckley-Leverett theory with explicit coupling terms

    Science.gov (United States)

    Pasquier, Sylvain; Quintard, Michel; Davit, Yohan

    2017-10-01

    Continuum models that describe two-phase flow of immiscible fluids in porous media often treat momentum exchange between the two phases by simply generalizing the single-phase Darcy law and introducing saturation-dependent permeabilities. Here we study models of creeping flows that include an explicit coupling between both phases via the addition of cross terms in the generalized Darcy law. Using an extension of the Buckley-Leverett theory, we analyze the impact of these cross terms on saturation profiles and pressure drops for different couples of fluids and closure relations of the effective parameters. We show that these cross terms in the macroscale models may significantly impact the flow compared to results obtained with the generalized Darcy laws without cross terms. Analytical solutions, validated against experimental data, suggest that the effect of this coupling on the dynamics of saturation fronts and the steady-state profiles is very sensitive to gravitational effects, the ratio of viscosity between the two phases, and the permeability. Our results indicate that the effects of momentum exchange on two-phase flow may increase with the permeability of the porous medium when the influence of the fluid-fluid interfaces become similar to that of the solid-fluid interfaces.

  11. Foldamer dynamics expressed via Markov state models. I. Explicit solvent molecular-dynamics simulations in acetonitrile, chloroform, methanol, and water

    Science.gov (United States)

    Elmer, Sidney P.; Park, Sanghyun; Pande, Vijay S.

    2005-09-01

    In this article, we analyze the folding dynamics of an all-atom model of a polyphenylacetylene (pPA) 12-mer in explicit solvent for four common organic and aqueous solvents: acetonitrile, chloroform, methanol, and water. The solvent quality has a dramatic effect on the time scales in which pPA 12-mers fold. Acetonitrile was found to manifest ideal folding conditions as suggested by optimal folding times on the order of ˜100-200ns, depending on temperature. In contrast, chloroform and water were observed to hinder the folding of the pPA 12-mer due to extreme solvation conditions relative to acetonitrile; chloroform denatures the oligomer, whereas water promotes aggregation and traps. The pPA 12-mer in a pure methanol solution folded in ˜400ns at 300K, compared relative to the experimental 12-mer folding time of ˜160ns measured in a 1:1 v/v THF/methanol solution. Requisite in drawing the aforementioned conclusions, analysis techniques based on Markov state models are applied to multiple short independent trajectories to extrapolate the long-time scale dynamics of the 12-mer in each respective solvent. We review the theory of Markov chains and derive a method to impose detailed balance on a transition-probability matrix computed from simulation data.

  12. Reducing fertilizer-nitrogen losses from rowcrop landscapes: Insights and implications from a spatially explicit watershed model

    Science.gov (United States)

    McLellan, Eileen; Schilling, Keith; Robertson, Dale

    2015-01-01

    We present conceptual and quantitative models that predict changes in fertilizer-derived nitrogen delivery from rowcrop landscapes caused by agricultural conservation efforts implemented to reduce nutrient inputs and transport and increase nutrient retention in the landscape. To evaluate the relative importance of changes in the sources, transport, and sinks of fertilizer-derived nitrogen across a region, we use the spatially explicit SPAtially Referenced Regression On Watershed attributes watershed model to map the distribution, at the small watershed scale within the Upper Mississippi-Ohio River Basin (UMORB), of: (1) fertilizer inputs; (2) nutrient attenuation during delivery of those inputs to the UMORB outlet; and (3) nitrogen export from the UMORB outlet. Comparing these spatial distributions suggests that the amount of fertilizer input and degree of nutrient attenuation are both important in determining the extent of nitrogen export. From a management perspective, this means that agricultural conservation efforts to reduce nitrogen export would benefit by: (1) expanding their focus to include activities that restore and enhance nutrient processing in these highly altered landscapes; and (2) targeting specific types of best management practices to watersheds where they will be most valuable. Doing so successfully may result in a shift in current approaches to conservation planning, outreach, and funding.

  13. Self-Dual Configurations in a Generalized Abelian Chern-Simons-Higgs Model with Explicit Breaking of the Lorentz Covariance

    Directory of Open Access Journals (Sweden)

    Rodolfo Casana

    2016-01-01

    Full Text Available We have studied the existence of self-dual solitonic solutions in a generalization of the Abelian Chern-Simons-Higgs model. Such a generalization introduces two different nonnegative functions, ω1(|ϕ| and ω(|ϕ|, which split the kinetic term of the Higgs field, |Dμϕ|2→ω1(|ϕ||D0ϕ|2-ω(|ϕ||Dkϕ|2, breaking explicitly the Lorentz covariance. We have shown that a clean implementation of the Bogomolnyi procedure only can be implemented whether ω(|ϕ|∝β|ϕ|2β-2 with β≥1. The self-dual or Bogomolnyi equations produce an infinity number of soliton solutions by choosing conveniently the generalizing function ω1(|ϕ| which must be able to provide a finite magnetic field. Also, we have shown that by properly choosing the generalizing functions it is possible to reproduce the Bogomolnyi equations of the Abelian Maxwell-Higgs and Chern-Simons-Higgs models. Finally, some new self-dual |ϕ|6-vortex solutions have been analyzed from both theoretical and numerical point of view.

  14. Spatially explicit, nano-mechanical models of the muscle half-sarcomere: Implications for biomechanical tuning in atrophy and fatigue

    Science.gov (United States)

    Kataoka, Aya; Tanner, Bertrand C. W.; Macpherson, J. Michael; Xu, Xiangrong; Wang, Qi; Regnier, Michael; Daniel, Thomas L.; Chase, P. Bryant

    2007-01-01

    Astronaut biomechanical performance depends on a wide variety of factors. Results from computational modelling suggest that muscle function—a key component of performance—could be modulated by compliance of the contractile filaments in muscle, especially when force is low such as transient Ca activation in a twitch, reduced activation in muscle fatigue encountered during EVA, or perhaps atrophy during prolonged space flight. We used Monte-Carlo models to investigate the hypotheses that myofilament compliance influences muscle function during a twitch, and also modulates the effects of cooperative interactions between contractile proteins on force generation. Peak twitch force and the kinetics of force decay were both decreased, while tension cost was increased, when myofilament compliance was increased relative to physiological values. Both the apparent Ca sensitivity and cooperativity of activation of steady-state isometric force were altered by myofilament compliance even when there were no explicit interactions included between binding sites. The effects of cooperative interactions between adjacent regulatory units were found to be greater than either the effect of myofilament compliance on apparent cooperativity of activation or that due to myosin cross-bridge-induced cooperativity. These results indicate that muscle function may be "tuned" at the molecular level, particularly under conditions of reduced Ca activation.

  15. Error Modeling and Sensitivity Analysis of a Five-Axis Machine Tool

    Directory of Open Access Journals (Sweden)

    Wenjie Tian

    2014-01-01

    Full Text Available Geometric error modeling and its sensitivity analysis are carried out in this paper, which is helpful for precision design of machine tools. Screw theory and rigid body kinematics are used to establish the error model of an RRTTT-type five-axis machine tool, which enables the source errors affecting the compensable and uncompensable pose accuracy of the machine tool to be explicitly separated, thereby providing designers and/or field engineers with an informative guideline for the accuracy improvement by suitable measures, that is, component tolerancing in design, manufacturing, and assembly processes, and error compensation. The sensitivity analysis method is proposed, and the sensitivities of compensable and uncompensable pose accuracies are analyzed. The analysis results will be used for the precision design of the machine tool.

  16. Light Scattering Tools for Cosmic Dust Modeling

    Science.gov (United States)

    Il'in, V. B.; Voshchinnikov, N. V.; Farafonov, V. G.; Henning, Th.; Perelman, A. Ya.

    Because cosmic dust grains vary significantly in both morphology and chemical composition, it is necessary to develop different light scattering tools to analyze their scattering properties and to reconcile these properties with observations. We present a set of recently developed tools which includes a database of optical constants of materials of astronomical interest, exact and approximate methods and numerical codes using various models of a non-spherical inhomogeneous scatterer, a database of optical properties of non-spherical particles, a new approach to find a solution of ill-posed inverse problems in optics, and an original polarized radiation-transfer code applicable to 3D media populated by aligned non-spherical scatterers.

  17. WMT: The CSDMS Web Modeling Tool

    Science.gov (United States)

    Piper, M.; Hutton, E. W. H.; Overeem, I.; Syvitski, J. P.

    2015-12-01

    The Community Surface Dynamics Modeling System (CSDMS) has a mission to enable model use and development for research in earth surface processes. CSDMS strives to expand the use of quantitative modeling techniques, promotes best practices in coding, and advocates for the use of open-source software. To streamline and standardize access to models, CSDMS has developed the Web Modeling Tool (WMT), a RESTful web application with a client-side graphical interface and a server-side database and API that allows users to build coupled surface dynamics models in a web browser on a personal computer or a mobile device, and run them in a high-performance computing (HPC) environment. With WMT, users can: Design a model from a set of components Edit component parameters Save models to a web-accessible server Share saved models with the community Submit runs to an HPC system Download simulation results The WMT client is an Ajax application written in Java with GWT, which allows developers to employ object-oriented design principles and development tools such as Ant, Eclipse and JUnit. For deployment on the web, the GWT compiler translates Java code to optimized and obfuscated JavaScript. The WMT client is supported on Firefox, Chrome, Safari, and Internet Explorer. The WMT server, written in Python and SQLite, is a layered system, with each layer exposing a web service API: wmt-db: database of component, model, and simulation metadata and output wmt-api: configure and connect components wmt-exe: launch simulations on remote execution servers The database server provides, as JSON-encoded messages, the metadata for users to couple model components, including descriptions of component exchange items, uses and provides ports, and input parameters. Execution servers are network-accessible computational resources, ranging from HPC systems to desktop computers, containing the CSDMS software stack for running a simulation. Once a simulation completes, its output, in NetCDF, is packaged

  18. Using the SECI knowledge management model and other tools to ...

    African Journals Online (AJOL)

    ... for example, through artefacts that the indigenous people produce, music, story telling and through the SECI knowledge management model produced by Nonaka and Takeuchi (1995). The SECI model links tacit and explicit knowledge through four phases: socialization, externalization, combination and internalization.

  19. Student Model Tools Code Release and Documentation

    DEFF Research Database (Denmark)

    Johnson, Matthew; Bull, Susan; Masci, Drew

    This document contains a wealth of information about the design and implementation of the Next-TELL open learner model. Information is included about the final specification (Section 3), the interfaces and features (Section 4), its implementation and technical design (Section 5) and also a summary...... of its strengths and areas of improvement (Section 6). Several key appendices are attached to this report including user manuals for teacher and students (Appendix 3). Fundamentally, all relevant information is included in the report for those wishing to do further development work with the tool...

  20. Comparison of BrainTool to other UML modeling and model transformation tools

    Science.gov (United States)

    Nikiforova, Oksana; Gusarovs, Konstantins

    2017-07-01

    In the last 30 years there were numerous model generated software systems offered targeting problems with the development productivity and the resulting software quality. CASE tools developed due today's date are being advertised as having "complete code-generation capabilities". Nowadays the Object Management Group (OMG) is calling similar arguments in regards to the Unified Modeling Language (UML) models at different levels of abstraction. It is being said that software development automation using CASE tools enables significant level of automation. Actual today's CASE tools are usually offering a combination of several features starting with a model editor and a model repository for a traditional ones and ending with code generator (that could be using a scripting or domain-specific (DSL) language), transformation tool to produce the new artifacts from the manually created and transformation definition editor to define new transformations for the most advanced ones. Present paper contains the results of CASE tool (mainly UML editors) comparison against the level of the automation they are offering.

  1. Biophysical modeling of brain tumor progression: From unconditionally stable explicit time integration to an inverse problem with parabolic PDE constraints for model calibration.

    Science.gov (United States)

    Mang, Andreas; Toma, Alina; Schuetz, Tina A; Becker, Stefan; Eckey, Thomas; Mohr, Christian; Petersen, Dirk; Buzug, Thorsten M

    2012-07-01

    A novel unconditionally stable, explicit numerical method is introduced to the field of modeling brain cancer progression on a tissue level together with an inverse problem (IP) based on optimal control theory that allows for automated model calibration with respect to observations in clinical imaging data. Biophysical models of cancer progression on a tissue level are in general based on the assumption that the spatiotemporal spread of cancerous cells is determined by cell division and net migration. These processes are typically described in terms of a parabolic partial differential equation (PDE). In the present work a parallelized implementation of an unconditionally stable, explicit Euler (EE(⋆) ) time integration method for the solution of this PDE is detailed. The key idea of the discussed EE(⋆) method is to relax the strong stability requirement on the spectral radius of the coefficient matrix by introducing a subdivision regime for a given outer time step. The performance is related to common implicit numerical methods. To quantify the numerical error, a simplified model that has a closed form solution is considered. To allow for a systematic, phenomenological validation a novel approach for automated model calibration on the basis of observations in medical imaging data is developed. The resulting IP is based on optimal control theory and manifests as a large scale, PDE constrained optimization problem. The numerical error of the EE(⋆) method is at the order of standard implicit numerical methods. The computing times are well below those obtained for implicit methods and by that demonstrate efficiency. Qualitative and quantitative analysis in 12 patients demonstrates that the obtained results are in strong agreement with observations in medical imaging data. Rating simulation success in terms of the mean overlap between model predictions and manual expert segmentations yields a success rate of 75% (9 out of 12 patients). The discussed EE(⋆) method

  2. Spatially explicit modeling of animal tuberculosis at the wildlife-livestock interface in Ciudad Real province, Spain.

    Science.gov (United States)

    LaHue, Nathaniel P; Baños, Joaquín Vicente; Acevedo, Pelayo; Gortázar, Christian; Martínez-López, Beatriz

    2016-06-01

    Eurasian wild boar (Sus scrofa) and red deer (Cervus elaphus) are the most important wildlife reservoirs for animal tuberculosis (TB) caused by the Mycobacterium tuberculosis complex (MTC), in Mediterranean Spain. These species are considered to play an important role in the transmission and persistence of MTC in cattle in some regions; however the factors contributing to the risk of transmission at the wildlife-livestock interface and the areas at highest risk for such transmission are largely unknown. This study sought to identify geographic areas where wildlife-livestock interactions are most likely to occur and to characterize the environmental and management factors at this interface contributing to persistence, incidence, and occurrence of TB on cattle farms, in one of the provinces with higher TB prevalence in Spain, Ciudad Real. We used spatially explicit, ecological niche models to evaluate the importance of factors such as wildlife demographics and hunting management, land use, climatic, and environmental variables as well as TB status in wildlife for TB breakdown (model 1), persistence (model 2) and new infection (model 3) on cattle farms and to generate high resolution maps of predicted TB occurrence to guide risk-based interventions. Models revealed that land use, particularly open area and woodland, high wild boar TB prevalence, and close proximity to fenced hunting estates were the most important factors associated with TB infection on cattle farms. This is the first time that local TB prevalence in wild boar for individual hunting estates has been significantly associated with TB occurrence on cattle farms at a local scale. Prediction maps identified two areas with high likelihood of TB occurrence in the southwest and northwest of the province where wildlife-livestock interactions and TB occurrence are highly likely and where TB preventative and mitigation strategies (e.g. targeted vaccination, increased biosecurity, etc.) should be prioritized

  3. Surface Protonation at the Rutile (110) Interface: Explicit Incorporation of Solvation Structure within the Refined MUSIC Model Framework

    Energy Technology Data Exchange (ETDEWEB)

    Machesky, Michael L. [Illinois State Water Survey, Champaign, IL; Predota, M. [University of South Bohemia, Czech Republic; Wesolowski, David J [ORNL

    2008-01-01

    The detailed solvation structure at the (110) surface of rutile ({alpha}-TiO{sub 2}) in contact with bulk liquid water has been obtained primarily from experimentally verified classical molecular dynamics (CMD) simulations of the ab initio-optimized surface in contact with SPC/E water. The results are used to explicitly quantify H-bonding interactions, which are then used within the refined MUSIC model framework to predict surface oxygen protonation constants. Quantum mechanical molecular dynamics (QMD) simulations in the presence of freely dissociable water molecules produced H-bond distributions around deprotonated surface oxygens very similar to those obtained by CMD with nondissociable SPC/E water, thereby confirming that the less computationally intensive CMD simulations provide accurate H-bond information. Utilizing this H-bond information within the refined MUSIC model, along with manually adjusted Ti-O surface bond lengths that are nonetheless within 0.05 {angstrom} of those obtained from static density functional theory (DFT) calculations and measured in X-ray reflectivity experiments (as well as bulk crystal values), give surface protonation constants that result in a calculated zero net proton charge pH value (pHznpc) at 25 C that agrees quantitatively with the experimentally determined value (5.4 {+-} 0.2) for a specific rutile powder dominated by the (110) crystal face. Moreover, the predicted pH{sub znpc} values agree to within 0.1 pH unit with those measured at all temperatures between 10 and 250 C. A slightly smaller manual adjustment of the DFT-derived Ti-O surface bond lengths was sufficient to bring the predicted pH{sub znpc} value of the rutile (110) surface at 25 C into quantitative agreement with the experimental value (4.8 {+-} 0.3) obtained from a polished and annealed rutile (110) single crystal surface in contact with dilute sodium nitrate solutions using second harmonic generation (SHG) intensity measurements as a function of ionic

  4. Surface protonation at the rutile (110) interface: explicit incorporation of solvation structure within the refined MUSIC model framework.

    Science.gov (United States)

    Machesky, Michael L; Predota, Milan; Wesolowski, David J; Vlcek, Lukas; Cummings, Peter T; Rosenqvist, Jörgen; Ridley, Moira K; Kubicki, James D; Bandura, Andrei V; Kumar, Nitin; Sofo, Jorge O

    2008-11-04

    The detailed solvation structure at the (110) surface of rutile (alpha-TiO2) in contact with bulk liquid water has been obtained primarily from experimentally verified classical molecular dynamics (CMD) simulations of the ab initio-optimized surface in contact with SPC/E water. The results are used to explicitly quantify H-bonding interactions, which are then used within the refined MUSIC model framework to predict surface oxygen protonation constants. Quantum mechanical molecular dynamics (QMD) simulations in the presence of freely dissociable water molecules produced H-bond distributions around deprotonated surface oxygens very similar to those obtained by CMD with nondissociable SPC/E water, thereby confirming that the less computationally intensive CMD simulations provide accurate H-bond information. Utilizing this H-bond information within the refined MUSIC model, along with manually adjusted Ti-O surface bond lengths that are nonetheless within 0.05 A of those obtained from static density functional theory (DFT) calculations and measured in X-ray reflectivity experiments (as well as bulk crystal values), give surface protonation constants that result in a calculated zero net proton charge pH value (pHznpc) at 25 degrees C that agrees quantitatively with the experimentally determined value (5.4+/-0.2) for a specific rutile powder dominated by the (110) crystal face. Moreover, the predicted pHznpc values agree to within 0.1 pH unit with those measured at all temperatures between 10 and 250 degrees C. A slightly smaller manual adjustment of the DFT-derived Ti-O surface bond lengths was sufficient to bring the predicted pHznpcvalue of the rutile (110) surface at 25 degrees C into quantitative agreement with the experimental value (4.8+/-0.3) obtained from a polished and annealed rutile (110) single crystal surface in contact with dilute sodium nitrate solutions using second harmonic generation (SHG) intensity measurements as a function of ionic strength

  5. A watershed-based spatially-explicit demonstration of an integrated environmental modeling framework for ecosystem services in the Coal River Basin (WV, USA)

    Science.gov (United States)

    John M. Johnston; Mahion C. Barber; Kurt Wolfe; Mike Galvin; Mike Cyterski; Rajbir Parmar; Luis Suarez

    2016-01-01

    We demonstrate a spatially-explicit regional assessment of current condition of aquatic ecoservices in the Coal River Basin (CRB), with limited sensitivity analysis for the atmospheric contaminant mercury. The integrated modeling framework (IMF) forecasts water quality and quantity, habitat suitability for aquatic biota, fish biomasses, population densities, ...

  6. Planning a red squirrel conservation area: using a spatially explicit population dynamics model to predict the impact of felling and forest design plans

    NARCIS (Netherlands)

    Lurz, P.W.W.; Geddes, N.; Lloyd, A.J.; Shirley, M.D.E.; Rushton, B.; Burlton, B.

    2003-01-01

    This paper describes the use of a spatially explicit population model (SEPM) to investigate the effects of different forest management strategies on a red squirrel conservation area. The study was based in woodland managed by Forest Enterprise, which manages 75 000 ha of woodlands in Northumberland,

  7. A tool for simulating and communicating uncertainty when modelling species distributions under future climates.

    Science.gov (United States)

    Gould, Susan F; Beeton, Nicholas J; Harris, Rebecca M B; Hutchinson, Michael F; Lechner, Alex M; Porfirio, Luciana L; Mackey, Brendan G

    2014-12-01

    Tools for exploring and communicating the impact of uncertainty on spatial prediction are urgently needed, particularly when projecting species distributions to future conditions.We provide a tool for simulating uncertainty, focusing on uncertainty due to data quality. We illustrate the use of the tool using a Tasmanian endemic species as a case study. Our simulations provide probabilistic, spatially explicit illustrations of the impact of uncertainty on model projections. We also illustrate differences in model projections using six different global climate models and two contrasting emissions scenarios.Our case study results illustrate how different sources of uncertainty have different impacts on model output and how the geographic distribution of uncertainty can vary.Synthesis and applications: We provide a conceptual framework for understanding sources of uncertainty based on a review of potential sources of uncertainty in species distribution modelling; a tool for simulating uncertainty in species distribution models; and protocols for dealing with uncertainty due to climate models and emissions scenarios. Our tool provides a step forward in understanding and communicating the impacts of uncertainty on species distribution models under future climates which will be particularly helpful for informing discussions between researchers, policy makers, and conservation practitioners.

  8. DATA QUALITY TOOLS FOR DATAWAREHOUSE MODELS

    OpenAIRE

    JASPREETI SINGH; SRISHTI VASHISHTHA

    2015-01-01

    Data quality tools aim at detecting and correcting data problems that influence the accuracy and efficiency of data analysis applications. Data warehousing activities require data quality tools to ready the data and ensure that clean data populates the warehouse, thus raising usability of the warehouse. This research targets on the problems in the data that are addressed by data quality tools. We classify data quality tools based on datawarehouse stages and features of tool; which address ...

  9. Collaboro: a collaborative (meta modeling tool

    Directory of Open Access Journals (Sweden)

    Javier Luis Cánovas Izquierdo

    2016-10-01

    Full Text Available Software development is becoming more and more collaborative, emphasizing the role of end-users in the development process to make sure the final product will satisfy customer needs. This is especially relevant when developing Domain-Specific Modeling Languages (DSMLs, which are modeling languages specifically designed to carry out the tasks of a particular domain. While end-users are actually the experts of the domain for which a DSML is developed, their participation in the DSML specification process is still rather limited nowadays. In this paper, we propose a more community-aware language development process by enabling the active participation of all community members (both developers and end-users from the very beginning. Our proposal, called Collaboro, is based on a DSML itself enabling the representation of change proposals during the language design and the discussion (and trace back of possible solutions, comments and decisions arisen during the collaboration. Collaboro also incorporates a metric-based recommender system to help community members to define high-quality notations for the DSMLs. We also show how Collaboro can be used at the model-level to facilitate the collaborative specification of software models. Tool support is available both as an Eclipse plug-in a web-based solution.

  10. Probabilistic modelling in urban drainage – two approaches that explicitly account for temporal variation of model errors

    DEFF Research Database (Denmark)

    Löwe, Roland; Del Giudice, Dario; Mikkelsen, Peter Steen

    to observations. After a brief discussion of the assumptions made for likelihood-based parameter inference, we illustrated the basic principles of both approaches on the example of sewer flow modelling with a conceptual rainfallrunoff model. The results from a real-world case study suggested that both approaches...

  11. SMART: a spatially explicit bio-economic model for assessing and managing demersal fisheries, with an application to italian trawlers in the strait of sicily.

    Directory of Open Access Journals (Sweden)

    Tommaso Russo

    Full Text Available Management of catches, effort and exploitation pattern are considered the most effective measures to control fishing mortality and ultimately ensure productivity and sustainability of fisheries. Despite the growing concerns about the spatial dimension of fisheries, the distribution of resources and fishing effort in space is seldom considered in assessment and management processes. Here we propose SMART (Spatial MAnagement of demersal Resources for Trawl fisheries, a tool for assessing bio-economic feedback in different management scenarios. SMART combines information from different tasks gathered within the European Data Collection Framework on fisheries and is composed of: 1 spatial models of fishing effort, environmental characteristics and distribution of demersal resources; 2 an Artificial Neural Network which captures the relationships among these aspects in a spatially explicit way and uses them to predict resources abundances; 3 a deterministic module which analyzes the size structure of catches and the associated revenues, according to different spatially-based management scenarios. SMART is applied to demersal fishery in the Strait of Sicily, one of the most productive fisheries of the Mediterranean Sea. Three of the main target species are used as proxies for the whole range exploited by trawlers. After training, SMART is used to evaluate different management scenarios, including spatial closures, using a simulation approach that mimics the recent exploitation patterns. Results evidence good model performance, with a noteworthy coherence and reliability of outputs for the different components. Among others, the main finding is that a partial improvement in resource conditions can be achieved by means of nursery closures, even if the overall fishing effort in the area remains stable. Accordingly, a series of strategically designed areas of trawling closures could significantly improve the resource conditions of demersal fisheries in

  12. Fuzzy risk explicit interval linear programming model for end-of-life vehicle recycling planning in the EU.

    Science.gov (United States)

    Simic, Vladimir

    2015-01-01

    End-of-life vehicles (ELVs) are vehicles that have reached the end of their useful lives and are no longer registered or licensed for use. The ELV recycling problem has become very serious in the last decade and more and more efforts are made in order to reduce the impact of ELVs on the environment. This paper proposes the fuzzy risk explicit interval linear programming model for ELV recycling planning in the EU. It has advantages in reflecting uncertainties presented in terms of intervals in the ELV recycling systems and fuzziness in decision makers' preferences. The formulated model has been applied to a numerical study in which different decision maker types and several ELV types under two EU ELV Directive legislative cases were examined. This study is conducted in order to examine the influences of the decision maker type, the α-cut level, the EU ELV Directive and the ELV type on decisions about vehicle hulks procuring, storing unprocessed hulks, sorting generated material fractions, allocating sorted waste flows and allocating sorted metals. Decision maker type can influence quantity of vehicle hulks kept in storages. The EU ELV Directive and decision maker type have no influence on which vehicle hulk type is kept in the storage. Vehicle hulk type, the EU ELV Directive and decision maker type do not influence the creation of metal allocation plans, since each isolated metal has its regular destination. The valid EU ELV Directive eco-efficiency quotas can be reached even when advanced thermal treatment plants are excluded from the ELV recycling process. The introduction of the stringent eco-efficiency quotas will significantly reduce the quantities of land-filled waste fractions regardless of the type of decision makers who will manage vehicle recycling system. In order to reach these stringent quotas, significant quantities of sorted waste need to be processed in advanced thermal treatment plants. Proposed model can serve as the support for the European

  13. Evaluation of clinical information modeling tools.

    Science.gov (United States)

    Moreno-Conde, Alberto; Austin, Tony; Moreno-Conde, Jesús; Parra-Calderón, Carlos L; Kalra, Dipak

    2016-11-01

    Clinical information models are formal specifications for representing the structure and semantics of the clinical content within electronic health record systems. This research aims to define, test, and validate evaluation metrics for software tools designed to support the processes associated with the definition, management, and implementation of these models. The proposed framework builds on previous research that focused on obtaining agreement on the essential requirements in this area. A set of 50 conformance criteria were defined based on the 20 functional requirements agreed by that consensus and applied to evaluate the currently available tools. Of the 11 initiative developing tools for clinical information modeling identified, 9 were evaluated according to their performance on the evaluation metrics. Results show that functionalities related to management of data types, specifications, metadata, and terminology or ontology bindings have a good level of adoption. Improvements can be made in other areas focused on information modeling and associated processes. Other criteria related to displaying semantic relationships between concepts and communication with terminology servers had low levels of adoption. The proposed evaluation metrics were successfully tested and validated against a representative sample of existing tools. The results identify the need to improve tool support for information modeling and software development processes, especially in those areas related to governance, clinician involvement, and optimizing the technical validation of testing processes. This research confirmed the potential of these evaluation metrics to support decision makers in identifying the most appropriate tool for their organization. Los Modelos de Información Clínica son especificaciones para representar la estructura y características semánticas del contenido clínico en los sistemas de Historia Clínica Electrónica. Esta investigación define, prueba y valida

  14. Hydrophobic interactions in model enclosures from small to large length scales: non-additivity in explicit and implicit solvent models.

    Science.gov (United States)

    Wang, Lingle; Friesner, Richard A; Berne, B J

    2010-01-01

    The binding affinities between a united-atom methane and various model hydrophobic enclosures were studied through high accuracy free energy perturbation methods (FEP). We investigated the non-additivity of the hydrophobic interaction in these systems, measured by the deviation of its binding affinity from that predicted by the pairwise additivity approximation. While only small non-additivity effects were previously reported in the interactions in methane trimers, we found large cooperative effects (as large as -1.14 kcal mol(-1) or approximately a 25% increase in the binding affinity) and anti-cooperative effects (as large as 0.45 kcal mol(-1)) for these model enclosed systems. Decomposition of the total potential of mean force (PMF) into increasing orders of multi-body interactions indicates that the contributions of the higher order multi-body interactions can be either positive or negative in different systems, and increasing the order of multi-body interactions considered did not necessarily improve the accuracy. A general correlation between the sign of the non-additivity effect and the curvature of the solute molecular surface was observed. We found that implicit solvent models based on the molecular surface area (MSA) performed much better, not only in predicting binding affinities, but also in predicting the non-additivity effects, compared with models based on the solvent accessible surface area (SASA), suggesting that MSA is a better descriptor of the curvature of the solutes. We also show how the non-additivity contribution changes as the hydrophobicity of the plate is decreased from the dewetting regime to the wetting regime.

  15. Explicit criteria for prioritization of cataract surgery

    Directory of Open Access Journals (Sweden)

    Escobar Antonio

    2006-03-01

    Full Text Available Abstract Background Consensus techniques have been used previously to create explicit criteria to prioritize cataract extraction; however, the appropriateness of the intervention was not included explicitly in previous studies. We developed a prioritization tool for cataract extraction according to the RAND method. Methods Criteria were developed using a modified Delphi panel judgment process. A panel of 11 ophthalmologists was assembled. Ratings were analyzed regarding the level of agreement among panelists. We studied the effect of all variables on the final panel score using general linear and logistic regression models. Priority scoring systems were developed by means of optimal scaling and general linear models. The explicit criteria developed were summarized by means of regression tree analysis. Results Eight variables were considered to create the indications. Of the 310 indications that the panel evaluated, 22.6% were considered high priority, 52.3% intermediate priority, and 25.2% low priority. Agreement was reached for 31.9% of the indications and disagreement for 0.3%. Logistic regression and general linear models showed that the preoperative visual acuity of the cataractous eye, visual function, and anticipated visual acuity postoperatively were the most influential variables. Alternative and simple scoring systems were obtained by optimal scaling and general linear models where the previous variables were also the most important. The decision tree also shows the importance of the previous variables and the appropriateness of the intervention. Conclusion Our results showed acceptable validity as an evaluation and management tool for prioritizing cataract extraction. It also provides easy algorithms for use in clinical practice.

  16. Computer system for identification of tool wear model in hot forging

    Directory of Open Access Journals (Sweden)

    Wilkus Marek

    2016-01-01

    Full Text Available The aim of the research was to create a methodology that will enable effective and reliable prediction of the tool wear. The idea of the hybrid model, which accounts for various mechanisms of tool material deterioration, is proposed in the paper. The mechanisms, which were considered, include abrasive wear, adhesive wear, thermal fatigue, mechanical fatigue, oxidation and plastic deformation. Individual models of various complexity were used for separate phenomena and strategy of combination of these models in one hybrid system was developed to account for the synergy of various mechanisms. The complex hybrid model was built on the basis of these individual models for various wear mechanisms. The individual models expanded from phenomenological ones for abrasive wear to multi-scale methods for modelling micro cracks initiation and propagation utilizing virtual representations of granular microstructures. The latter have been intensively developed recently and they form potentially a powerful tool that allows modelling of thermal and mechanical fatigue, accounting explicitly for the tool material microstructure.

  17. Models and Modelling Tools for Chemical Product and Process Design

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    2016-01-01

    The design, development and reliability of a chemical product and the process to manufacture it, need to be consistent with the end-use characteristics of the desired product. One of the common ways to match the desired product-process characteristics is through trial and error based experiments......-based framework is that in the design, development and/or manufacturing of a chemical product-process, the knowledge of the applied phenomena together with the product-process design details can be provided with diverse degrees of abstractions and details. This would allow the experimental resources......, are the needed models for such a framework available? Or, are modelling tools that can help to develop the needed models available? Can such a model-based framework provide the needed model-based work-flows matching the requirements of the specific chemical product-process design problems? What types of models...

  18. Precision tools and models to narrow in on the 750 GeV diphoton resonance

    Energy Technology Data Exchange (ETDEWEB)

    Staub, Florian [CERN, Geneva (Switzerland). Theoretical Physics Dept.; Athron, Peter [Monash Univ., Melbourne (Australia). ARC Center of Excellence for Particle Physics at the Terascale; Basso, Lorenzo [Aix-Marseille Univ., CNRS-IN2P3, UMR 7346 (France). CPPM; and others

    2016-02-15

    The hints for a new resonance at 750 GeV from ATLAS and CMS have triggered a significant amount of attention. Since the simplest extensions of the standard model cannot accommodate the observation, many alternatives have been considered to explain the excess. Here we focus on several proposed renormalisable weakly-coupled models and revisit results given in the literature. We point out that physically important subtleties are often missed or neglected. To facilitate the study of the excess we have created a collection of 40 model files, selected from recent literature, for the Mathematica package SARAH. With SARAH one can generate files to perform numerical studies using the tailor-made spectrum generators FlexibleSUSY and SPheno. These have been extended to automatically include crucial higher order corrections to the diphoton and digluon decay rates for both CP-even and CP-odd scalars. Additionally, we have extended the UFO and CalcHep interfaces of SARAH, to pass the precise information about the effective vertices from the spectrum generator to a Monte-Carlo tool. Finally, as an example to demonstrate the power of the entire setup, we present a new supersymmetric model that accommodates the diphoton excess, explicitly demonstrating how a large width can be obtained. We explicitly show several steps in detail to elucidate the use of these public tools in the precision study of this model.

  19. Precision tools and models to narrow in on the 750 GeV diphoton resonance

    Energy Technology Data Exchange (ETDEWEB)

    Staub, Florian [CERN, Theoretical Physics Department, Geneva (Switzerland); Athron, Peter [Monash University, ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, Melbourne, VIC (Australia); Basso, Lorenzo [CPPM, Aix-Marseille Universite, CNRS-IN2P3, UMR 7346, Marseille Cedex 9 (France); Goodsell, Mark D. [Sorbonne Universites, LPTHE, UMR 7589, CNRS and Universite Pierre et Marie Curie, Paris Cedex 05 (France); Harries, Dylan [The University of Adelaide, Department of Physics, ARC Centre of Excellence for Particle Physics at the Terascale, Adelaide, SA (Australia); Krauss, Manuel E.; Nickel, Kilian; Opferkuch, Toby [Bethe Center for Theoretical Physics and Physikalisches Institut der Universitaet Bonn, Bonn (Germany); Ubaldi, Lorenzo [Tel-Aviv University, Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv (Israel); Vicente, Avelino [Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia), Valencia (Spain); Voigt, Alexander [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany)

    2016-09-15

    The hints for a new resonance at 750 GeV from ATLAS and CMS have triggered a significant amount of attention. Since the simplest extensions of the standard model cannot accommodate the observation, many alternatives have been considered to explain the excess. Here we focus on several proposed renormalisable weakly-coupled models and revisit results given in the literature. We point out that physically important subtleties are often missed or neglected. To facilitate the study of the excess we have created a collection of 40 model files, selected from recent literature, for the Mathematica package SARAH. With SARAH one can generate files to perform numerical studies using the tailor-made spectrum generators FlexibleSUSY and SPheno. These have been extended to automatically include crucial higher order corrections to the diphoton and digluon decay rates for both CP-even and CP-odd scalars. Additionally, we have extended the UFO and CalcHep interfaces of SARAH, to pass the precise information about the effective vertices from the spectrum generator to a Monte-Carlo tool. Finally, as an example to demonstrate the power of the entire setup, we present a new supersymmetric model that accommodates the diphoton excess, explicitly demonstrating how a large width can be obtained. We explicitly show several steps in detail to elucidate the use of these public tools in the precision study of this model. (orig.)

  20. Memory Efficient Data Structures for Explicit Verification of Timed Systems

    DEFF Research Database (Denmark)

    Taankvist, Jakob Haahr; Srba, Jiri; Larsen, Kim Guldstrand

    2014-01-01

    Timed analysis of real-time systems can be performed using continuous (symbolic) or discrete (explicit) techniques. The explicit state-space exploration can be considerably faster for models with moderately small constants, however, at the expense of high memory consumption. In the setting of timed......-arc Petri nets, we explore new data structures for lowering the used memory: PTries for efficient storing of configurations and time darts for semi-symbolic description of the state-space. Both methods are implemented as a part of the tool TAPAAL and the experiments document at least one order of magnitude...... of memory savings while preserving comparable verification times....

  1. Modeling, methodologies and tools for molecular and nano-scale communications modeling, methodologies and tools

    CERN Document Server

    Nakano, Tadashi; Moore, Michael

    2017-01-01

    (Preliminary) The book presents the state of art in the emerging field of molecular and nanoscale communication. It gives special attention to fundamental models, and advanced methodologies and tools used in the field. It covers a wide range of applications, e.g. nanomedicine, nanorobot communication, bioremediation and environmental managements. It addresses advanced graduate students, academics and professionals working at the forefront in their fields and at the interfaces between different areas of research, such as engineering, computer science, biology and nanotechnology.

  2. Towards anatomic scale agent-based modeling with a massively parallel spatially explicit general-purpose model of enteric tissue (SEGMEnT_HPC.

    Directory of Open Access Journals (Sweden)

    Robert Chase Cockrell

    Full Text Available Perhaps the greatest challenge currently facing the biomedical research community is the ability to integrate highly detailed cellular and molecular mechanisms to represent clinical disease states as a pathway to engineer effective therapeutics. This is particularly evident in the representation of organ-level pathophysiology in terms of abnormal tissue structure, which, through histology, remains a mainstay in disease diagnosis and staging. As such, being able to generate anatomic scale simulations is a highly desirable goal. While computational limitations have previously constrained the size and scope of multi-scale computational models, advances in the capacity and availability of high-performance computing (HPC resources have greatly expanded the ability of computational models of biological systems to achieve anatomic, clinically relevant scale. Diseases of the intestinal tract are exemplary examples of pathophysiological processes that manifest at multiple scales of spatial resolution, with structural abnormalities present at the microscopic, macroscopic and organ-levels. In this paper, we describe a novel, massively parallel computational model of the gut, the Spatially Explicitly General-purpose Model of Enteric Tissue_HPC (SEGMEnT_HPC, which extends an existing model of the gut epithelium, SEGMEnT, in order to create cell-for-cell anatomic scale simulations. We present an example implementation of SEGMEnT_HPC that simulates the pathogenesis of ileal pouchitis, and important clinical entity that affects patients following remedial surgery for ulcerative colitis.

  3. Large scale experiments as a tool for numerical model development

    DEFF Research Database (Denmark)

    Kirkegaard, Jens; Hansen, Erik Asp; Fuchs, Jesper

    2003-01-01

    Experimental modelling is an important tool for study of hydrodynamic phenomena. The applicability of experiments can be expanded by the use of numerical models and experiments are important for documentation of the validity of numerical tools. In other cases numerical tools can be applied for im...... hydrodynamic interaction with structures. The examples also show that numerical model development benefits from international co-operation and sharing of high quality results.......Experimental modelling is an important tool for study of hydrodynamic phenomena. The applicability of experiments can be expanded by the use of numerical models and experiments are important for documentation of the validity of numerical tools. In other cases numerical tools can be applied...... for improvement of the reliability of physical model results. This paper demonstrates by examples that numerical modelling benefits in various ways from experimental studies (in large and small laboratory facilities). The examples range from very general hydrodynamic descriptions of wave phenomena to specific...

  4. Simulation Tools Model Icing for Aircraft Design

    Science.gov (United States)

    2012-01-01

    the years from strictly a research tool to one used routinely by industry and other government agencies. Glenn contractor William Wright has been the architect of this development, supported by a team of researchers investigating icing physics, creating validation data, and ensuring development according to standard software engineering practices. The program provides a virtual simulation environment for determining where water droplets strike an airfoil in flight, what kind of ice would result, and what shape that ice would take. Users can enter geometries for specific, two-dimensional cross sections of an airfoil or other airframe surface and then apply a range of inputs - different droplet sizes, temperatures, airspeeds, and more - to model how ice would build up on the surface in various conditions. The program s versatility, ease of use, and speed - LEWICE can run through complex icing simulations in only a few minutes - have contributed to it becoming a popular resource in the aviation industry.

  5. Evaluation of the Event Driven Phenology Model Coupled with the VegET Evapotranspiration Model Through Comparisons with Reference Datasets in a Spatially Explicit Manner

    Science.gov (United States)

    Kovalskyy, V.; Henebry, G. M.; Adusei, B.; Hansen, M.; Roy, D. P.; Senay, G.; Mocko, D. M.

    2011-01-01

    A new model coupling scheme with remote sensing data assimilation was developed for estimation of daily actual evapotranspiration (ET). The scheme represents a mix of the VegET, a physically based model to estimate ET from a water balance, and an event driven phenology model (EDPM), where the EDPM is an empirically derived crop specific model capable of producing seasonal trajectories of canopy attributes. In this experiment, the scheme was deployed in a spatially explicit manner within the croplands of the Northern Great Plains. The evaluation was carried out using 2007-2009 land surface forcing data from the North American Land Data Assimilation System (NLDAS) and crop maps derived from remotely sensed data of NASA's Moderate Resolution Imaging Spectroradiometer (MODIS). We compared the canopy parameters produced by the phenology model with normalized difference vegetation index (NDVI) data derived from the MODIS nadir bi-directional reflectance distribution function (BRDF) adjusted reflectance (NBAR) product. The expectations of the EDPM performance in prognostic mode were met, producing determination coefficient (r2) of 0.8 +/-.0.15. Model estimates of NDVI yielded root mean square error (RMSE) of 0.1 +/-.0.035 for the entire study area. Retrospective correction of canopy dynamics with MODIS NDVI brought the errors down to just below 10% of observed data range. The ET estimates produced by the coupled scheme were compared with ones from the MODIS land product suite. The expected r2=0.7 +/-.15 and RMSE = 11.2 +/-.4 mm per 8 days were met and even exceeded by the coupling scheme0 functioning in both prognostic and retrospective modes. Minor setbacks of the EDPM and VegET performance (r2 about 0.5 and additional 30 % of RMSR) were found on the peripheries of the study area and attributed to the insufficient EDPM training and to spatially varying accuracy of crop maps. Overall the experiment provided sufficient evidence of soundness and robustness of the EDPM and

  6. Development and reliability of the explicit professional oral communication observation tool to quantify the use of non-technical skills in healthcare.

    Science.gov (United States)

    Kemper, Peter F; van Noord, Inge; de Bruijne, Martine; Knol, Dirk L; Wagner, Cordula; van Dyck, Cathy

    2013-07-01

    A lack of non-technical skills is increasingly recognised as an important underlying cause of adverse events in healthcare. The nature and number of things professionals communicate to each other can be perceived as a product of their use of non-technical skills. This paper describes the development and reliability of an instrument to measure and quantify the use of non-technical skills by direct observations of explicit professional oral communication (EPOC) in the clinical situation. In an iterative process we translated, tested and refined an existing checklist from the aviation industry, called self, human interaction, aircraft, procedures and environment, in the context of healthcare, notably emergency departments (ED) and intensive care units (ICU). The EPOC comprises six dimensions: assertiveness, working with others; task-oriented leadership; people-oriented leadership; situational awareness; planning and anticipation. Each dimension is specified into several concrete items reflecting verbal behaviours. The EPOC was evaluated in four ED and six ICU. In the ED and ICU, respectively, 378 and 1144 individual and 51 and 68 contemporaneous observations of individual staff members were conducted. All EPOC dimensions occur frequently, apart from assertiveness, which was hardly observed. Intraclass correlations for the overall EPOC score ranged between 0.85 and 0.91 and for underlying EPOC dimensions between 0.53 and 0.95. The EPOC is a new instrument for evaluating the use of non-technical skills in healthcare, which is reliable in two highly different settings. By quantifying professional behaviour the instrument facilitates measurement of behavioural change over time. The results suggest that EPOC can also be translated to other settings.

  7. GMF: A Model Migration Case for the Transformation Tool Contest

    Directory of Open Access Journals (Sweden)

    Markus Herrmannsdoerfer

    2011-11-01

    Full Text Available Using a real-life evolution taken from the Graphical Modeling Framework, we invite submissions to explore ways in which model transformation and migration tools can be used to migrate models in response to metamodel adaptation.

  8. Comparing strengths and weaknesses of three ecosystem services modelling tools in a diverse UK river catchment.

    Science.gov (United States)

    Sharps, Katrina; Masante, Dario; Thomas, Amy; Jackson, Bethanna; Redhead, John; May, Linda; Prosser, Havard; Cosby, Bernard; Emmett, Bridget; Jones, Laurence

    2017-04-15

    Ecosystem services modelling tools can help land managers and policy makers evaluate the impacts of alternative management options or changes in land use on the delivery of ecosystem services. As the variety and complexity of these tools increases, there is a need for comparative studies across a range of settings, allowing users to make an informed choice. Using examples of provisioning and regulating services (water supply, carbon storage and nutrient retention), we compare three spatially explicit tools - LUCI (Land Utilisation and Capability Indicator), ARIES (Artificial Intelligence for Ecosystem Services) and InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs). Models were parameterised for the UK and applied to a temperate catchment with widely varying land use in North Wales. Although each tool provides quantitative mapped output, can be applied in different contexts, and can work at local or national scale, they differ in the approaches taken and underlying assumptions made. In this study, we focus on the wide range of outputs produced for each service and discuss the differences between each modelling tool. Model outputs were validated using empirical data for river flow, carbon and nutrient levels within the catchment. The sensitivity of the models to land-use change was tested using four scenarios of varying severity, evaluating the conversion of grassland habitat to woodland (0-30% of the landscape). We show that, while the modelling tools provide broadly comparable quantitative outputs, each has its own unique features and strengths. Therefore the choice of tool depends on the study question. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  9. Explicit/multi-parametric model predictive control (MPC) of linear discrete-time systems by dynamic and multi-parametric programming

    KAUST Repository

    Kouramas, K.I.

    2011-08-01

    This work presents a new algorithm for solving the explicit/multi- parametric model predictive control (or mp-MPC) problem for linear, time-invariant discrete-time systems, based on dynamic programming and multi-parametric programming techniques. The algorithm features two key steps: (i) a dynamic programming step, in which the mp-MPC problem is decomposed into a set of smaller subproblems in which only the current control, state variables, and constraints are considered, and (ii) a multi-parametric programming step, in which each subproblem is solved as a convex multi-parametric programming problem, to derive the control variables as an explicit function of the states. The key feature of the proposed method is that it overcomes potential limitations of previous methods for solving multi-parametric programming problems with dynamic programming, such as the need for global optimization for each subproblem of the dynamic programming step. © 2011 Elsevier Ltd. All rights reserved.

  10. A spatially explicit whole-system model of the lignocellulosic bioethanol supply chain: an assessment of decentralised processing potential

    Science.gov (United States)

    Dunnett, Alex J; Adjiman, Claire S; Shah, Nilay

    2008-01-01

    Background Lignocellulosic bioethanol technologies exhibit significant capacity for performance improvement across the supply chain through the development of high-yielding energy crops, integrated pretreatment, hydrolysis and fermentation technologies and the application of dedicated ethanol pipelines. The impact of such developments on cost-optimal plant location, scale and process composition within multiple plant infrastructures is poorly understood. A combined production and logistics model has been developed to investigate cost-optimal system configurations for a range of technological, system scale, biomass supply and ethanol demand distribution scenarios specific to European agricultural land and population densities. Results Ethanol production costs for current technologies decrease significantly from $0.71 to $0.58 per litre with increasing economies of scale, up to a maximum single-plant capacity of 550 × 106 l year-1. The development of high-yielding energy crops and consolidated bio-processing realises significant cost reductions, with production costs ranging from $0.33 to $0.36 per litre. Increased feedstock yields result in systems of eight fully integrated plants operating within a 500 × 500 km2 region, each producing between 1.24 and 2.38 × 109 l year-1 of pure ethanol. A limited potential for distributed processing and centralised purification systems is identified, requiring developments in modular, ambient pretreatment and fermentation technologies and the pipeline transport of pure ethanol. Conclusion The conceptual and mathematical modelling framework developed provides a valuable tool for the assessment and optimisation of the lignocellulosic bioethanol supply chain. In particular, it can provide insight into the optimal configuration of multiple plant systems. This information is invaluable in ensuring (near-)cost-optimal strategic development within the sector at the regional and national scale. The framework is flexible and can thus

  11. DYNAMO-HIA--a Dynamic Modeling tool for generic Health Impact Assessments.

    Science.gov (United States)

    Lhachimi, Stefan K; Nusselder, Wilma J; Smit, Henriette A; van Baal, Pieter; Baili, Paolo; Bennett, Kathleen; Fernández, Esteve; Kulik, Margarete C; Lobstein, Tim; Pomerleau, Joceline; Mackenbach, Johan P; Boshuizen, Hendriek C

    2012-01-01

    Currently, no standard tool is publicly available that allows researchers or policy-makers to quantify the impact of policies using epidemiological evidence within the causal framework of Health Impact Assessment (HIA). A standard tool should comply with three technical criteria (real-life population, dynamic projection, explicit risk-factor states) and three usability criteria (modest data requirements, rich model output, generally accessible) to be useful in the applied setting of HIA. With DYNAMO-HIA (Dynamic Modeling for Health Impact Assessment), we introduce such a generic software tool specifically designed to facilitate quantification in the assessment of the health impacts of policies. DYNAMO-HIA quantifies the impact of user-specified risk-factor changes on multiple diseases and in turn on overall population health, comparing one reference scenario with one or more intervention scenarios. The Markov-based modeling approach allows for explicit risk-factor states and simulation of a real-life population. A built-in parameter estimation module ensures that only standard population-level epidemiological evidence is required, i.e. data on incidence, prevalence, relative risks, and mortality. DYNAMO-HIA provides a rich output of summary measures--e.g. life expectancy and disease-free life expectancy--and detailed data--e.g. prevalences and mortality/survival rates--by age, sex, and risk-factor status over time. DYNAMO-HIA is controlled via a graphical user interface and is publicly available from the internet, ensuring general accessibility. We illustrate the use of DYNAMO-HIA with two example applications: a policy causing an overall increase in alcohol consumption and quantifying the disease-burden of smoking. By combining modest data needs with general accessibility and user friendliness within the causal framework of HIA, DYNAMO-HIA is a potential standard tool for health impact assessment based on epidemiologic evidence.

  12. DYNAMO-HIA–A Dynamic Modeling Tool for Generic Health Impact Assessments

    Science.gov (United States)

    Lhachimi, Stefan K.; Nusselder, Wilma J.; Smit, Henriette A.; van Baal, Pieter; Baili, Paolo; Bennett, Kathleen; Fernández, Esteve; Kulik, Margarete C.; Lobstein, Tim; Pomerleau, Joceline; Mackenbach, Johan P.; Boshuizen, Hendriek C.

    2012-01-01

    Background Currently, no standard tool is publicly available that allows researchers or policy-makers to quantify the impact of policies using epidemiological evidence within the causal framework of Health Impact Assessment (HIA). A standard tool should comply with three technical criteria (real-life population, dynamic projection, explicit risk-factor states) and three usability criteria (modest data requirements, rich model output, generally accessible) to be useful in the applied setting of HIA. With DYNAMO-HIA (Dynamic Modeling for Health Impact Assessment), we introduce such a generic software tool specifically designed to facilitate quantification in the assessment of the health impacts of policies. Methods and Results DYNAMO-HIA quantifies the impact of user-specified risk-factor changes on multiple diseases and in turn on overall population health, comparing one reference scenario with one or more intervention scenarios. The Markov-based modeling approach allows for explicit risk-factor states and simulation of a real-life population. A built-in parameter estimation module ensures that only standard population-level epidemiological evidence is required, i.e. data on incidence, prevalence, relative risks, and mortality. DYNAMO-HIA provides a rich output of summary measures – e.g. life expectancy and disease-free life expectancy – and detailed data – e.g. prevalences and mortality/survival rates – by age, sex, and risk-factor status over time. DYNAMO-HIA is controlled via a graphical user interface and is publicly available from the internet, ensuring general accessibility. We illustrate the use of DYNAMO-HIA with two example applications: a policy causing an overall increase in alcohol consumption and quantifying the disease-burden of smoking. Conclusion By combining modest data needs with general accessibility and user friendliness within the causal framework of HIA, DYNAMO-HIA is a potential standard tool for health impact assessment based on

  13. DYNAMO-HIA--a Dynamic Modeling tool for generic Health Impact Assessments.

    Directory of Open Access Journals (Sweden)

    Stefan K Lhachimi

    Full Text Available BACKGROUND: Currently, no standard tool is publicly available that allows researchers or policy-makers to quantify the impact of policies using epidemiological evidence within the causal framework of Health Impact Assessment (HIA. A standard tool should comply with three technical criteria (real-life population, dynamic projection, explicit risk-factor states and three usability criteria (modest data requirements, rich model output, generally accessible to be useful in the applied setting of HIA. With DYNAMO-HIA (Dynamic Modeling for Health Impact Assessment, we introduce such a generic software tool specifically designed to facilitate quantification in the assessment of the health impacts of policies. METHODS AND RESULTS: DYNAMO-HIA quantifies the impact of user-specified risk-factor changes on multiple diseases and in turn on overall population health, comparing one reference scenario with one or more intervention scenarios. The Markov-based modeling approach allows for explicit risk-factor states and simulation of a real-life population. A built-in parameter estimation module ensures that only standard population-level epidemiological evidence is required, i.e. data on incidence, prevalence, relative risks, and mortality. DYNAMO-HIA provides a rich output of summary measures--e.g. life expectancy and disease-free life expectancy--and detailed data--e.g. prevalences and mortality/survival rates--by age, sex, and risk-factor status over time. DYNAMO-HIA is controlled via a graphical user interface and is publicly available from the internet, ensuring general accessibility. We illustrate the use of DYNAMO-HIA with two example applications: a policy causing an overall increase in alcohol consumption and quantifying the disease-burden of smoking. CONCLUSION: By combining modest data needs with general accessibility and user friendliness within the causal framework of HIA, DYNAMO-HIA is a potential standard tool for health impact assessment based

  14. Assessment of the Simulated Molecular Composition with the GECKO-A Modeling Tool Using Chamber Observations for α-Pinene.

    Science.gov (United States)

    Aumont, B.; Camredon, M.; Isaacman-VanWertz, G. A.; Karam, C.; Valorso, R.; Madronich, S.; Kroll, J. H.

    2016-12-01

    Gas phase oxidation of VOC is a gradual process leading to the formation of multifunctional organic compounds, i.e., typically species with higher oxidation state, high water solubility and low volatility. These species contribute to the formation of secondary organic aerosols (SOA) viamultiphase processes involving a myriad of organic species that evolve through thousands of reactions and gas/particle mass exchanges. Explicit chemical mechanisms reflect the understanding of these multigenerational oxidation steps. These mechanisms rely directly on elementary reactions to describe the chemical evolution and track the identity of organic carbon through various phases down to ultimate oxidation products. The development, assessment and improvement of such explicit schemes is a key issue, as major uncertainties remain on the chemical pathways involved during atmospheric oxidation of organic matter. An array of mass spectrometric techniques (CIMS, PTRMS, AMS) was recently used to track the composition of organic species during α-pinene oxidation in the MIT environmental chamber, providing an experimental database to evaluate and improve explicit mechanisms. In this study, the GECKO-A tool (Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere) is used to generate fully explicit oxidation schemes for α-pinene multiphase oxidation simulating the MIT experiment. The ability of the GECKO-A chemical scheme to explain the organic molecular composition in the gas and the condensed phases is explored. First results of this model/observation comparison at the molecular level will be presented.

  15. Computer-Aided Modelling Methods and Tools

    DEFF Research Database (Denmark)

    Cameron, Ian; Gani, Rafiqul

    2011-01-01

    . To illustrate these concepts a number of examples are used. These include models of polymer membranes, distillation and catalyst behaviour. Some detailed considerations within these models are stated and discussed. Model generation concepts are introduced and ideas of a reference model are given that shows...

  16. Advanced reach tool (ART) : Development of the mechanistic model

    NARCIS (Netherlands)

    Fransman, W.; Tongeren, M. van; Cherrie, J.W.; Tischer, M.; Schneider, T.; Schinkel, J.; Kromhout, H.; Warren, N.; Goede, H.; Tielemans, E.

    2011-01-01

    This paper describes the development of the mechanistic model within a collaborative project, referred to as the Advanced REACH Tool (ART) project, to develop a tool to model inhalation exposure for workers sharing similar operational conditions across different industries and locations in Europe.

  17. Storm Water Management Model Climate Adjustment Tool (SWMM-CAT)

    Science.gov (United States)

    The US EPA’s newest tool, the Stormwater Management Model (SWMM) – Climate Adjustment Tool (CAT) is meant to help municipal stormwater utilities better address potential climate change impacts affecting their operations. SWMM, first released in 1971, models hydrology and hydrauli...

  18. Dynamic wind turbine models in power system simulation tool

    DEFF Research Database (Denmark)

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

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

  19. Systematic Methods and Tools for Computer Aided Modelling

    DEFF Research Database (Denmark)

    Fedorova, Marina

    aided methods and tools, that include procedures to perform model translation, model analysis, model verification/validation, model solution and model documentation; 4) model transfer – export/import to/from other application for further extension and application – several types of formats, such as XML......Models are playing important roles in design and analysis of chemicals/bio-chemicals based products and the processes that manufacture them. Model-based methods and tools have the potential to decrease the number of experiments, which can be expensive and time consuming, and point to candidates...

  20. Tampa Bay Water Clarity Model (TBWCM): As a Predictive Tool

    Science.gov (United States)

    The Tampa Bay Water Clarity Model was developed as a predictive tool for estimating the impact of changing nutrient loads on water clarity as measured by secchi depth. The model combines a physical mixing model with an irradiance model and nutrient cycling model. A 10 segment bi...

  1. An explicitly solvated full atomistic model of the cardiac thin filament and application on the calcium binding affinity effects from familial hypertrophic cardiomyopathy linked mutations

    Science.gov (United States)

    Williams, Michael; Schwartz, Steven

    2015-03-01

    The previous version of our cardiac thin filament (CTF) model consisted of the troponin complex (cTn), two coiled-coil dimers of tropomyosin (Tm), and 29 actin units. We now present the newest revision of the model to include explicit solvation. The model was developed to continue our study of genetic mutations in the CTF proteins which are linked to familial hypertrophic cardiomyopathies. Binding of calcium to the cTnC subunit causes subtle conformational changes to propagate through the cTnC to the cTnI subunit which then detaches from actin. Conformational changes propagate through to the cTnT subunit, which allows Tm to move into the open position along actin, leading to muscle contraction. Calcium disassociation allows for the reverse to occur, which results in muscle relaxation. The inclusion of explicit TIP3 water solvation allows for the model to get better individual local solvent to protein interactions; which are important when observing the N-lobe calcium binding pocket of the cTnC. We are able to compare in silica and in vitro experimental results to better understand the physiological effects from mutants, such as the R92L/W and F110V/I of the cTnT, on the calcium binding affinity compared to the wild type.

  2. Applying Modeling Tools to Ground System Procedures

    Science.gov (United States)

    Di Pasquale, Peter

    2012-01-01

    As part of a long-term effort to revitalize the Ground Systems (GS) Engineering Section practices, Systems Modeling Language (SysML) and Business Process Model and Notation (BPMN) have been used to model existing GS products and the procedures GS engineers use to produce them.

  3. An explicit representation of vertical momentum transport in a multiscale modeling framework through its 2-D cloud-resolving model component

    Science.gov (United States)

    Cheng, Anning; Xu, Kuan-Man

    2014-03-01

    In this study, an explicit representation of vertical momentum transport by convective cloud systems, including mesoscale convective systems (MCSs), is proposed and tested in a multiscale modeling framework (MMF). The embedded cloud-resolving model (CRM) provides vertical momentum transport in one horizontal direction. The vertical momentum transport in the other direction is assumed to be proportional to the vertical mass flux diagnosed from the CRM in addition to the effects of entrainment and detrainment. In order to represent both upgradient and downgradient vertical momentum transports, the orientation of the embedded CRM must change with time instead of being stationary typically in MMFs. The orientation is determined by the stratification of the lower troposphere and environmental wind shear. Introducing the variation of the orientations of the embedded CRM is responsible for reducing the stationary anomalous precipitation and many improvements. Improvements are strengthened when the CRM simulated vertical momentum transport is allowed to modify the large-scale circulation simulated by the host general circulation model. These include an improved spatial distribution, amplitude, and intraseasonal variability of the surface precipitation in the tropics, more realistic zonal mean diabatic heating and drying patterns, more reasonable zonal mean large-scale circulations and the East Asian summer monsoon circulation, and an improved, annual mean implied meridional ocean transport in the Southern Hemisphere. Further tests of this convective momentum transport parameterization scheme will be performed with a higher-resolution MMF to further understand its roles in the intraseasonal oscillation and tropical waves, monsoon circulation, and zonal mean large-scale circulations.

  4. Shape: A 3D Modeling Tool for Astrophysics.

    Science.gov (United States)

    Steffen, Wolfgang; Koning, Nicholas; Wenger, Stephan; Morisset, Christophe; Magnor, Marcus

    2011-04-01

    We present a flexible interactive 3D morpho-kinematical modeling application for astrophysics. Compared to other systems, our application reduces the restrictions on the physical assumptions, data type, and amount that is required for a reconstruction of an object's morphology. It is one of the first publicly available tools to apply interactive graphics to astrophysical modeling. The tool allows astrophysicists to provide a priori knowledge about the object by interactively defining 3D structural elements. By direct comparison of model prediction with observational data, model parameters can then be automatically optimized to fit the observation. The tool has already been successfully used in a number of astrophysical research projects.

  5. MODEL OF GENERALIZED MACHINE-TOOL

    Directory of Open Access Journals (Sweden)

    Sandu CONSTANTIN

    2017-06-01

    Full Text Available This paper presents a revolutionary and modern concept according to whom the computer can mold and shape a machine tool, generating surfaces of the machined parts with an accuracy of less than 0.01μm. This concept has been verified in many cases as: machining of cylindrical spur gears; machined worm wheel; parallel type worm manufacturing of solids handling pump; centerless grinding machine, some aspects of finishing cylindrical gears by shaving cutter, and so on. Also with the help of this concept can be determined the machining of the parts in conditions of real inaccuracy of the machine and / or vibration.

  6. MODEL OF GENERALIZED MACHINE-TOOL

    OpenAIRE

    Sandu CONSTANTIN; Dana TILINA

    2017-01-01

    This paper presents a revolutionary and modern concept according to whom the computer can mold and shape a machine tool, generating surfaces of the machined parts with an accuracy of less than 0.01μm. This concept has been verified in many cases as: machining of cylindrical spur gears; machined worm wheel; parallel type worm manufacturing of solids handling pump; centerless grinding machine, some aspects of finishing cylindrical gears by shaving cutter, and so on. Also with the help of this c...

  7. Modeling Behavior by Coastal River Otter (Lontra Canadensis in Response to Prey Availability in Prince William Sound, Alaska: A Spatially-Explicit Individual-Based Approach.

    Directory of Open Access Journals (Sweden)

    Shannon E Albeke

    Full Text Available Effects of climate change on animal behavior and cascading ecosystem responses are rarely evaluated. In coastal Alaska, social river otters (Lontra Canadensis, largely males, cooperatively forage on schooling fish and use latrine sites to communicate group associations and dominance. Conversely, solitary otters, mainly females, feed on intertidal-demersal fish and display mutual avoidance via scent marking. This behavioral variability creates "hotspots" of nutrient deposition and affects plant productivity and diversity on the terrestrial landscape. Because the abundance of schooling pelagic fish is predicted to decline with climate change, we developed a spatially-explicit individual-based model (IBM of otter behavior and tested six scenarios based on potential shifts to distribution patterns of schooling fish. Emergent patterns from the IBM closely mimicked observed otter behavior and landscape use in the absence of explicit rules of intraspecific attraction or repulsion. Model results were most sensitive to rules regarding spatial memory and activity state following an encounter with a fish school. With declining availability of schooling fish, the number of social groups and the time simulated otters spent in the company of conspecifics declined. Concurrently, model results suggested an elevation of defecation rate, a 25% increase in nitrogen transport to the terrestrial landscape, and significant changes to the spatial distribution of "hotspots" with declines in schooling fish availability. However, reductions in availability of schooling fish could lead to declines in otter density over time.

  8. Jack Human Modelling Tool: A Review

    Science.gov (United States)

    2010-01-01

    CAD objects using its native modelling capability, such as a sphere, cone, cylinder, or cube, which can be used as building blocks to create more...the 2000 Digital Human Modeling conference [33] (only a powerpoint presentation was included on the conference proceedings CD). Limited information ...Computer and Information Sciences. 25. Monheit, G. and N.I. Badler, A kinematic model of the human spine and torso. IEEE Computer Graphics & Applications

  9. ‘Safety Matters Have Become Too Important for Management to Leave it Up to the Workers’ –The Nordic OSH Model Between Implicit and Explicit Frameworks

    Directory of Open Access Journals (Sweden)

    Johnny Dyreborg

    2011-01-01

    Full Text Available In a globalized economy it is relevant to question whether the Nordic Working Environment (WE model will remain as the basic and implicit framework for the governance of the WE. This paper explores institutional changes in the governance of the WE, and critically examines how a more explicit and market-oriented framework might influence the governance of the WE in the Nordic countries. Firstly, the paper examines the changes in the governance of the WE at the societal level (Denmark for the period 1954 - 2007, and identifies institutional logics informing these changes. Secondly, the paper examines changes in the governance of the WE at the level of the construction sector, using case material from four of the largest construction projects completed in Denmark in recent years. The analyses reveal three discrete periods, representing distinct logics influencing the governance of the WE, i.e., the logic of the state, the logic of democracy and the logic of the market. The logic of the state and the logic of democracy represent an implicit framework, whereas the logic of the market entails a shift to a more explicit framework. The shift to a more explicit framework for the governance of the WE, is also identified at the level of the construction sector. This leads to a pivotal shift in the clients' and the construction companies' relationship with the institutional environment in the four large construction projects. From worker representatives being the primary stakeholders, to a shift where the fulcrum of the development of the WE lies between management, the state and stakeholders in the companies' environment. This shift opens up a range of new and more market-oriented approaches to the governance of the WE that seems to challenge the extant Nordic WE model.

  10. Novel multiscale modeling tool applied to Pseudomonas aeruginosa biofilm formation.

    Directory of Open Access Journals (Sweden)

    Matthew B Biggs

    Full Text Available Multiscale modeling is used to represent biological systems with increasing frequency and success. Multiscale models are often hybrids of different modeling frameworks and programming languages. We present the MATLAB-NetLogo extension (MatNet as a novel tool for multiscale modeling. We demonstrate the utility of the tool with a multiscale model of Pseudomonas aeruginosa biofilm formation that incorporates both an agent-based model (ABM and constraint-based metabolic modeling. The hybrid model correctly recapitulates oxygen-limited biofilm metabolic activity and predicts increased growth rate via anaerobic respiration with the addition of nitrate to the growth media. In addition, a genome-wide survey of metabolic mutants and biofilm formation exemplifies the powerful analyses that are enabled by this computational modeling tool.

  11. Novel multiscale modeling tool applied to Pseudomonas aeruginosa biofilm formation.

    Science.gov (United States)

    Biggs, Matthew B; Papin, Jason A

    2013-01-01

    Multiscale modeling is used to represent biological systems with increasing frequency and success. Multiscale models are often hybrids of different modeling frameworks and programming languages. We present the MATLAB-NetLogo extension (MatNet) as a novel tool for multiscale modeling. We demonstrate the utility of the tool with a multiscale model of Pseudomonas aeruginosa biofilm formation that incorporates both an agent-based model (ABM) and constraint-based metabolic modeling. The hybrid model correctly recapitulates oxygen-limited biofilm metabolic activity and predicts increased growth rate via anaerobic respiration with the addition of nitrate to the growth media. In addition, a genome-wide survey of metabolic mutants and biofilm formation exemplifies the powerful analyses that are enabled by this computational modeling tool.

  12. Density Functional Theory Calculation of pKa's of Thiols in Aqueous Solution Using Explicit Water Molecules and the Polarizable Continuum Model.

    Science.gov (United States)

    Thapa, Bishnu; Schlegel, H Bernhard

    2016-07-21

    The pKa's of substituted thiols are important for understanding their properties and reactivities in applications in chemistry, biochemistry, and material chemistry. For a collection of 175 different density functionals and the SMD implicit solvation model, the average errors in the calculated pKa's of methanethiol and ethanethiol are almost 10 pKa units higher than for imidazole. A test set of 45 substituted thiols with pKa's ranging from 4 to 12 has been used to assess the performance of 8 functionals with 3 different basis sets. As expected, the basis set needs to include polarization functions on the hydrogens and diffuse functions on the heavy atoms. Solvent cavity scaling was ineffective in correcting the errors in the calculated pKa's. Inclusion of an explicit water molecule that is hydrogen bonded with the H of the thiol group (in neutral) or S(-) (in thiolates) lowers error by an average of 3.5 pKa units. With one explicit water and the SMD solvation model, pKa's calculated with the M06-2X, PBEPBE, BP86, and LC-BLYP functionals are found to deviate from the experimental values by about 1.5-2.0 pKa units whereas pKa's with the B3LYP, ωB97XD and PBEVWN5 functionals are still in error by more than 3 pKa units. The inclusion of three explicit water molecules lowers the calculated pKa further by about 4.5 pKa units. With the B3LYP and ωB97XD functionals, the calculated pKa's are within one unit of the experimental values whereas most other functionals used in this study underestimate the pKa's. This study shows that the ωB97XD functional with the 6-31+G(d,p) and 6-311++G(d,p) basis sets, and the SMD solvation model with three explicit water molecules hydrogen bonded to the sulfur produces the best result for the test set (average error -0.11 ± 0.50 and +0.15 ± 0.58, respectively). The B3LYP functional also performs well (average error -1.11 ± 0.82 and -0.78 ± 0.79, respectively).

  13. Linking land use change to recreational fishery valuation with a spatially explicit behavior model: A case study from Tampa Bay, FL USA

    Science.gov (United States)

    Drawing a link between habitat change and production and delivery of ecosystem services is a priority in coastal estuarine ecosystems. This link is needed to fully understand how human communities can influence ecosystem sustainability. Mechanistic modeling tools are highly fun...

  14. New tools for aquatic habitat modeling

    Science.gov (United States)

    D. Tonina; J. A. McKean; C. Tang; P. Goodwin

    2011-01-01

    Modeling of aquatic microhabitat in streams has been typically done over short channel reaches using one-dimensional simulations, partly because of a lack of high resolution. subaqueous topographic data to better define model boundary conditions. The Experimental Advanced Airborne Research Lidar (EAARL) is an airborne aquatic-terrestrial sensor that allows simultaneous...

  15. Towards a generalized energy prediction model for machine tools.

    Science.gov (United States)

    Bhinge, Raunak; Park, Jinkyoo; Law, Kincho H; Dornfeld, David A; Helu, Moneer; Rachuri, Sudarsan

    2017-04-01

    Energy prediction of machine tools can deliver many advantages to a manufacturing enterprise, ranging from energy-efficient process planning to machine tool monitoring. Physics-based, energy prediction models have been proposed in the past to understand the energy usage pattern of a machine tool. However, uncertainties in both the machine and the operating environment make it difficult to predict the energy consumption of the target machine reliably. Taking advantage of the opportunity to collect extensive, contextual, energy-consumption data, we discuss a data-driven approach to develop an energy prediction model of a machine tool in this paper. First, we present a methodology that can efficiently and effectively collect and process data extracted from a machine tool and its sensors. We then present a data-driven model that can be used to predict the energy consumption of the machine tool for machining a generic part. Specifically, we use Gaussian Process (GP) Regression, a non-parametric machine-learning technique, to develop the prediction model. The energy prediction model is then generalized over multiple process parameters and operations. Finally, we apply this generalized model with a method to assess uncertainty intervals to predict the energy consumed to machine any part using a Mori Seiki NVD1500 machine tool. Furthermore, the same model can be used during process planning to optimize the energy-efficiency of a machining process.

  16. Spatially explicit models of full-season productivity and implications for landscape management of Golden-winged Warblers in the western Great Lakes Region: Chapter 9

    Science.gov (United States)

    Peterson, Sean M.; Streby, Henry M.; Andersen, David E.

    2016-01-01

    The relationship between landscape structure and composition and full-season productivity (FSP) is poorly understood for most birds. For species of high conservation concern, insight into how productivity is related to landscape structure and composition can be used to develop more effective conservation strategies that increase recruitment. We monitored nest productivity and fledgling survival of Golden-winged Warblers (Vermivora chrysoptera), a species of high conservation concern, in managed forest landscapes at two sites in northern Minnesota, and one site in southeastern Manitoba, Canada from 2010 to 2012. We used logistic exposure models to identify the influence of landscape structure and composition on nest productivity and fledgling survival. We used the models to predict spatially explicit, FSP across our study sites to identify areas of low relative productivity that could be targeted for management. We then used our models of spatially explicit, FSP to simulate the impact of potential management actions on our study sites with the goal of increasing total population productivity. Unlike previous studies that suggested wetland cover types provide higher quality breeding habitat for Golden-winged Warblers, our models predicted 14% greater productivity in upland cover types. Simulated succession of a 9-ha grassland patch to a shrubby upland suitable for nesting increased the total number of fledglings produced by that patch and adjacent upland shrublands by 30%, despite decreasing individual productivity by 13%. Further simulated succession of the same patch described above into deciduous forest reduced the total number of fledglings produced to independence on a landscape by 18% because of a decrease in the area available for nesting. Simulated reduction in the cumulative length of shrubby edge within a 50-m radius of any location in our landscapes from 0.6 to 0.3 km increased FSP by 5%. Our models demonstrated that the effects of any single management

  17. Modeling the Formation and Composition of Secondary Organic Aerosol from Diesel Exhaust Using Parameterized and Semi-Explicit Chemistry and Thermodynamic Models

    Science.gov (United States)

    Eluri, Sailaja

    oxygen space) from the SOM compared favorably to gas-phase measurements made using a Chemical Ionization Mass Spectrometer (CIMS) that, qualitatively, substantiated the semi-explicit chemistry captured by the SOM and the measurements made by the CIMS. Sensitivity simulations suggested that (a) IVOCs from diesel exhaust could be modeled using a single surrogate species with an SOA mass yield equivalent to a C15 or C17 linear alkane for use in large-scale models, (b) different diesel exhaust emissions profiles in the literature resulted in the same SOA production as long as IVOCs were included and (c) accounting for vapor wall loss parameterizations for the SOA precursors improved model performance. As OFRs are increasingly used to study SOA formation and evolution in laboratory and field environments, there is a need to develop models that can be used to interpret the OFR data. This work is one example of the model development and application relevant to the use of OFRs.

  18. An explicit relaxation filtering framework based upon Perona-Malik anisotropic diffusion for shock capturing and subgrid scale modeling of Burgers turbulence

    CERN Document Server

    Maulik, Romit

    2016-01-01

    In this paper, we introduce a relaxation filtering closure approach to account for subgrid scale effects in explicitly filtered large eddy simulations using the concept of anisotropic diffusion. We utilize the Perona-Malik diffusion model and demonstrate its shock capturing ability and spectral performance for solving the Burgers turbulence problem, which is a simplified prototype for more realistic turbulent flows showing the same quadratic nonlinearity. Our numerical assessments present the behavior of various diffusivity functions in conjunction with a detailed sensitivity analysis with respect to the free modeling parameters. In comparison to direct numerical simulation (DNS) and under-resolved DNS results, we find that the proposed closure model is efficient in the prevention of energy accumulation at grid cut-off and is also adept at preventing any possible spurious numerical oscillations due to shock formation under the optimal parameter choices. In contrast to other relaxation filtering approaches, it...

  19. Exploring the Dynamic Mechanisms of Farmland Abandonment Based on a Spatially Explicit Economic Model for Environmental Sustainability: A Case Study in Jiangxi Province, China

    Directory of Open Access Journals (Sweden)

    Hualin Xie

    2014-03-01

    Full Text Available Farmland abandonment has important impacts on biodiversity and ecosystem recovery, as well as food security and rural sustainable development. Due to rapid urbanization and industrialization, farmland abandonment has become an increasingly important problem in many countries, particularly in China. To promote sustainable land-use management and environmental sustainability, it is important to understand the socioeconomic causes and spatial patterns of farmland abandonment. In this study, we explored the dynamic mechanisms of farmland abandonment in Jiangxi province of China using a spatially explicit economical model. The results show that the variables associated with the agricultural products yield are significantly correlated with farmland abandonment. The increasing opportunity cost of farming labor is the main factor in farmland abandonment in conjunction with a rural labor shortage due to rural-to-urban population migration and regional industrialization. Farmlands are more likely to be abandoned in areas located far from the villages and towns due to higher transportation costs. Additionally, farmers with more land but lower net income are more likely to abandon poor-quality farmland. Our results support the hypothesis that farmland abandonment takes place in locations in which the costs of cultivation are high and the potential crop yield is low. In addition, our study also demonstrates that a spatially explicit economic model is necessary to distinguish between the main driving forces of farmland abandonment. Policy implications are also provided for potential future policy decisions.

  20. Direct versus Indirect Explicit Methods of Enhancing EFL Students' English Grammatical Competence: A Concept Checking-Based Consciousness-Raising Tasks Model

    Science.gov (United States)

    Dang, Trang Thi Doan; Nguyen, Huong Thu

    2013-01-01

    Two approaches to grammar instruction are often discussed in the ESL literature: direct explicit grammar instruction (DEGI) (deduction) and indirect explicit grammar instruction (IEGI) (induction). This study aims to explore the effects of indirect explicit grammar instruction on EFL learners' mastery of English tenses. Ninety-four…

  1. Evaluating an Explicitly Coupled 3-D Soil Thermal-Hydrology and Carbon Nitrogen Reactive Transport Land Surface Model - CLM-PFLOTRAN

    Science.gov (United States)

    Yuan, F.; Painter, S. L.; Thornton, P. E.; Xu, X.; Tang, G.; Kumar, J.; Bisht, G.; Hammond, G. E.; Mills, R. T.; Wullschleger, S. D.

    2016-12-01

    In nature soil biophysical and biogeochemical processes are tightly coupled spatially and temporally. However due to constraints of both understanding of complexity of process interactions and computing ability, it still remains a challenge to represent fully coupled systems of soil thermal-hydrological dynamics and biogeochemical processes in land surface models (LSMs). In the Community Land Model (CLM), the land component of the Community Earth System Model (CESM), soil C-N processes are asynchronously coupled to thermal and hydrological processes, and lateral processes are not explicitly considered. PFLOTRAN is an open source, state-of-the-art massively parallel 3-D subsurface flow and reactive transport code. In this study, we have implemented CLM soil thermal-hydrological-biogeochemical processes in PFLOTRAN to explicitly synchronize them spatially and temporally. The resulting coupled CLM-PFLOTRAN model is a LSM capable of resolving 3-D soil thermal-hydrological-biogeochemical processes. The aboveground (CLM) and subsurface (PFLOTRAN) coupling is modularized. Hydrology, thermal-hydrology, and reactive-transport can be assessed separately or fully. We tested the model in fully 3-D coupled mode at the Next Generation Ecosystem Experiment-Arctic (NGEE-Arctic) field sites at the Barrow Environmental Observatory (BEO), AK. The simulations show that representation of synchronous coupling and lateral flows impact prediction of ecosystem dynamics across these polygonal tundra sites. The model is also evaluated globally in 1-D column mode showing significant differences compared to CLM, especially in N-limit regions. The developed CLM-PFLOTRAN framework will be used for regional evaluation of climate change-caused ecosystem process responses and their feedbacks to climate system.

  2. Aligning building information model tools and construction management methods

    NARCIS (Netherlands)

    Hartmann, Timo; van Meerveld, H.J.; Vossebeld, N.; Adriaanse, Adriaan Maria

    2012-01-01

    Few empirical studies exist that can explain how different Building Information Model (BIM) based tool implementation strategies work in practical contexts. To help overcoming this gap, this paper describes the implementation of two BIM based tools, the first, to support the activities at an

  3. Model based methods and tools for process systems engineering

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    Process systems engineering (PSE) provides means to solve a wide range of problems in a systematic and efficient manner. This presentation will give a perspective on model based methods and tools needed to solve a wide range of problems in product-process synthesis-design. These methods and tools...

  4. Sagebrush ecosystem conservation and management: ecoregional assessment tools and models for the Wyoming Basins

    Science.gov (United States)

    Hanser, S.E.; Leu, M.; Knick, S.T.; Aldridge, C.L.

    2011-01-01

    The Wyoming Basins are one of the remaining strongholds of the sagebrush ecosystem. However, like most sagebrush habitats, threats to this region are numerous. This book adds to current knowledge about the regional status of the sagebrush ecosystem, the distribution of habitats, the threats to the ecosystem, and the influence of threats and habitat conditions on occurrence and abundance of sagebrush associated fauna and flora in the Wyoming Basins. Comprehensive methods are outlined for use in data collection and monitoring of wildlife and plant populations. Field and spatial data are integrated into a spatially explicit analytical framework to develop models of species occurrence and abundance for the egion. This book provides significant new information on distributions, abundances, and habitat relationships for a number of species of conservation concern that depend on sagebrush in the region. The tools and models presented in this book increase our understanding of impacts from land uses and can contribute to the development of comprehensive management and conservation strategies.

  5. Agent Based Modeling as an Educational Tool

    Science.gov (United States)

    Fuller, J. H.; Johnson, R.; Castillo, V.

    2012-12-01

    Motivation is a key element in high school education. One way to improve motivation and provide content, while helping address critical thinking and problem solving skills, is to have students build and study agent based models in the classroom. This activity visually connects concepts with their applied mathematical representation. "Engaging students in constructing models may provide a bridge between frequently disconnected conceptual and mathematical forms of knowledge." (Levy and Wilensky, 2011) We wanted to discover the feasibility of implementing a model based curriculum in the classroom given current and anticipated core and content standards.; Simulation using California GIS data ; Simulation of high school student lunch popularity using aerial photograph on top of terrain value map.

  6. Modular target acquisition model & visualization tool

    NARCIS (Netherlands)

    Bijl, P.; Hogervorst, M.A.; Vos, W.K.

    2008-01-01

    We developed a software framework for image-based simulation models in the chain: scene-atmosphere-sensor-image enhancement-display-human observer: EO-VISTA. The goal is to visualize the steps and to quantify (Target Acquisition) task performance. EO-VISTA provides an excellent means to

  7. SIMULATION TOOLS FOR ELECTRICAL MACHINES MODELLING ...

    African Journals Online (AJOL)

    Dr Obe

    This paper illustrates the way MATLAB is used to model non-linearites in synchronous ... Keywords: Asynchronous machine; MATLAB scripts; engineering education; skin-effect; saturation effect; dynamic behavour. 1.0 Introduction .... algorithm of Marquardt [10] is employed. In figure 1, the estimated function becomes,.

  8. A community diagnostic tool for chemistry climate model validation

    Directory of Open Access Journals (Sweden)

    A. Gettelman

    2012-09-01

    Full Text Available This technical note presents an overview of the Chemistry-Climate Model Validation Diagnostic (CCMVal-Diag tool for model evaluation. The CCMVal-Diag tool is a flexible and extensible open source package that facilitates the complex evaluation of global models. Models can be compared to other models, ensemble members (simulations with the same model, and/or many types of observations. The initial construction and application is to coupled chemistry-climate models (CCMs participating in CCMVal, but the evaluation of climate models that submitted output to the Coupled Model Intercomparison Project (CMIP is also possible. The package has been used to assist with analysis of simulations for the 2010 WMO/UNEP Scientific Ozone Assessment and the SPARC Report on the Evaluation of CCMs. The CCMVal-Diag tool is described and examples of how it functions are presented, along with links to detailed descriptions, instructions and source code. The CCMVal-Diag tool supports model development as well as quantifies model changes, both for different versions of individual models and for different generations of community-wide collections of models used in international assessments. The code allows further extensions by different users for different applications and types, e.g. to other components of the Earth system. User modifications are encouraged and easy to perform with minimum coding.

  9. Building an explicit de Sitter

    Energy Technology Data Exchange (ETDEWEB)

    Louis, Jan [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Hamburg Univ. (Germany). Zentrum fuer Mathematische Physik; Rummel, Markus; Valandro, Roberto [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Westphal, Alexander [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie

    2012-11-15

    We construct an explicit example of a de Sitter vacuum in type IIB string theory that realizes the proposal of Kaehler uplifting. As the large volume limit in this method depends on the rank of the largest condensing gauge group we carry out a scan of gauge group ranks over the Kreuzer-Skarke set of toric Calabi-Yau threefolds. We find large numbers of models with the largest gauge group factor easily exceeding a rank of one hundred. We construct a global model with Kaehler uplifting on a two-parameter model on CP{sup 4}{sub 11169}, by an explicit analysis from both the type IIB and F-theory point of view. The explicitness of the construction lies in the realization of a D7 brane configuration, gauge flux and RR and NS flux choices, such that all known consistency conditions are met and the geometric moduli are stabilized in a metastable de Sitter vacuum with spontaneous GUT scale supersymmetry breaking driven by an F-term of the Kaehler moduli.

  10. A Repository for Beyond-the-Standard-Model Tools

    Energy Technology Data Exchange (ETDEWEB)

    Skands, P.; /Fermilab; Richardson, P.; Allanach, B.C.; Baer, H.; Belanger, G.; El Kacimi, M.; Ellwanger, U.; Freitas, A.; Ghodbane, N.; Goujdami, D.; Hahn, T.; Heinemeyer,; Kneur, J.-L.; Landsberg, G.; Lee, J.S.; Muhlleitner, M.; Ohl, T.; Perez, E.; Peskin, M.; Pilaftsis, A.; Plehn, T.

    2005-05-01

    To aid phenomenological studies of Beyond-the-Standard-Model (BSM) physics scenarios, a web repository for BSM calculational tools has been created. We here present brief overviews of the relevant codes, ordered by topic as well as by alphabet.

  11. Spatially explicit integrated modeling and economic valuation of climate driven land use change and its indirect effects

    OpenAIRE

    Bateman, Ian; Agarwala, Matthew; Binner, Amy; Coombes, Emma; Day, Brett; Ferrini, Silvia; Fezzi, Carlo; Hutchins, Michael; Lovett, Andrew; Posen, Paulette

    2016-01-01

    We present an integrated model of the direct consequences of climate change on land use, and the indirect effects of induced land use change upon the natural environment. The model predicts climate-driven shifts in the profitability of alternative uses of agricultural land. Both the direct impact of climate change and the induced shift in land use patterns will cause secondary effects on the water environment, for which agriculture is the major source of diffuse pollution. We model the impact...

  12. Multidisciplinary Modelling Tools for Power Electronic Circuits

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad

    This thesis presents multidisciplinary modelling techniques in a Design For Reliability (DFR) approach for power electronic circuits. With increasing penetration of renewable energy systems, the demand for reliable power conversion systems is becoming critical. Since a large part of electricity...... for expensive computation facilities in DFR approach. Therefore, in this thesis focus is placed on the generation of accurate, simple and generic models to study and assess thermal and electrical behavior of power electronic circuits (especially power modules). In this thesis, different power electronic...... is processed through power electronics, highly efficient, sustainable, reliable and cost-effective power electronic devices are needed. Reliability of a product is defined as the ability to perform within its predefined functions under given conditions in a specific time. Because power electronic devices...

  13. A general thermal model of machine tool spindle

    OpenAIRE

    Yanfang Dong; Zude Zhou; Mingyao Liu

    2017-01-01

    As the core component of machine tool, the thermal characteristics of the spindle have a significant influence on machine tool running status. Lack of an accurate model of the spindle system, particularly the model of load–deformation coefficient between the bearing rolling elements and rings, severely limits the thermal error analytic precision of the spindle. In this article, bearing internal loads, especially the function relationships between the principal curvature difference F(ρ) and au...

  14. Exploring tree species colonization potentials using a spatially explicit simulation model: implications for four oaks under climate change

    Science.gov (United States)

    Anantha M. Prasad; Judith D. Gardiner; Louis R. Iverson; Stephen N. Matthews; Matthew. Peters

    2013-01-01

    Climate change impacts tree species differentially by exerting unique pressures and altering their suitable habitats. We previously predicted these changes in suitable habitat for current and future climates using a species habitat model (DISTRIB) in the eastern United States. Based on the accuracy of the model, the species assemblages should eventually reflect the new...

  15. Global patterns of dissolved silica export to the coastal zone: Results from a spatially explicit global model

    NARCIS (Netherlands)

    Beusen, A.H.W.; Bouwman, A.F.; Dürr, H.H.; Dekkers, A.L.M.; Hartmann, J.

    2009-01-01

    We present a multiple linear regression model developed for describing global river export of dissolved SiO2 (DSi) to coastal zones. The model, with river basin spatial scale and an annual temporal scale, is based on four variables with a significant influence on DSi yields (soil bulk density,

  16. LANDIS 4.0 users guide. LANDIS: a spatially explicit model of forest landscape disturbance, management, and succession

    Science.gov (United States)

    Hong S. He; Wei Li; Brian R. Sturtevant; Jian Yang; Bo Z. Shang; Eric J. Gustafson; David J. Mladenoff

    2005-01-01

    LANDIS 4.0 is new-generation software that simulates forest landscape change over large spatial and temporal scales. It is used to explore how disturbances, succession, and management interact to determine forest composition and pattern. Also describes software architecture, model assumptions and provides detailed instructions on the use of the model.

  17. Rasp Tool on Phoenix Robotic Arm Model

    Science.gov (United States)

    2008-01-01

    This close-up photograph taken at the Payload Interoperability Testbed at the University of Arizona, Tucson, shows the motorized rasp protruding from the bottom of the scoop on the engineering model of NASA's Phoenix Mars Lander's Robotic Arm. The rasp will be placed against the hard Martian surface to cut into the hard material and acquire an icy soil sample for analysis by Phoenix's scientific instruments. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is led by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  18. Investigations on the impact of explicitly predicted snow metamorphism on the microclimate simulated by a meso-β/γ-scale non-hydrostatic model

    Science.gov (United States)

    Fröhlich, Kristina; Mölders, Nicole

    A snow model is developed, coupled to and tested within the framework of the meso-β/γ-scale non-hydrostatic model, Geesthacht's simulation model of the atmosphere (GESIMA). An evaluation of the snow model is conducted both in a stand-alone version and within GESIMA. In the stand-alone mode, it is evaluated at local scales using data routinely observed at Brandis (51.32°N, 12.62°E, 133 m NN, Saxony) between 1993 and 1997. The snow model reproduces reasonably the temporal evolution of the snow depth; however, it slightly underestimates snow depth, on average. In the coupled mode, simulations are performed with and without the snow model for a winter-storm snow event and a melt period in East Germany to examine the influence of explicitly modeled snow metamorphism on the simulated microclimate. The snow model reasonably predicts the effects typically associated with snow cover. Accuracy of predicted snow depth and extension depends on the lateral boundary conditions and snow prediction by the host model. Evaluation of the simulated air temperatures as well as humidity shows that the inclusion of the snow model improves the model performance as compared to the simulations without snow model. The results show that changing only the values of albedo and emissivity to those typical for snow, as often done in meso-β/γ-scale modeling of snow events, can even lead to opposite effects in simulated latent heat fluxes, ground heat fluxes, soil- and near-surface air temperatures than those typically associated with a snow cover. A rigorous evaluation of the snow simulations in coupled meso-β/γ-scale non-hydrostatic models requires datasets of snow properties (e.g., albedo and emissivity, snow cover extent, snow depth, snow water equivalent, snow temperature) in a high quality and resolution for the region under study. The available datasets are not yet ready to fulfil this objective.

  19. Modeling Tools for Drilling, Reservoir Navigation, and Formation Evaluation

    Directory of Open Access Journals (Sweden)

    Sushant Dutta

    2012-06-01

    Full Text Available The oil and gas industry routinely uses borehole tools for measuring or logging rock and fluid properties of geologic formations to locate hydrocarbons and maximize their production. Pore fluids in formations of interest are usually hydrocarbons or water. Resistivity logging is based on the fact that oil and gas have a substantially higher resistivity than water. The first resistivity log was acquired in 1927, and resistivity logging is still the foremost measurement used for drilling and evaluation. However, the acquisition and interpretation of resistivity logging data has grown in complexity over the years. Resistivity logging tools operate in a wide range of frequencies (from DC to GHz and encounter extremely high (several orders of magnitude conductivity contrast between the metal mandrel of the tool and the geologic formation. Typical challenges include arbitrary angles of tool inclination, full tensor electric and magnetic field measurements, and interpretation of complicated anisotropic formation properties. These challenges combine to form some of the most intractable computational electromagnetic problems in the world. Reliable, fast, and convenient numerical modeling of logging tool responses is critical for tool design, sensor optimization, virtual prototyping, and log data inversion. This spectrum of applications necessitates both depth and breadth of modeling software—from blazing fast one-dimensional (1-D modeling codes to advanced threedimensional (3-D modeling software, and from in-house developed codes to commercial modeling packages. In this paper, with the help of several examples, we demonstrate our approach for using different modeling software to address different drilling and evaluation applications. In one example, fast 1-D modeling provides proactive geosteering information from a deep-reading azimuthal propagation resistivity measurement. In the second example, a 3-D model with multiple vertical resistive fractures

  20. Modeling and Control of the Cobelli Model as a Personalized Prescriptive Tool for Diabetes Treatment

    Science.gov (United States)

    2016-11-05

    A TRIDENT SCHOLAR PROJECT REPORT NO. 445 Modeling and Control of the Cobelli Model as a Personalized Prescriptive Tool for Diabetes ...Trident Scholar project report; no. 445 (2016) MODELING AND CONTROL OF THE COBELLI MODEL AS A PERSONALIZED PRESCRIPTIVE TOOL FOR DIABETES ...To) 4. TITLE AND SUBTITLE Modeling and Control of the Cobelli Model as a Personalized Prescriptive Tool for Diabetes 5a. CONTRACT NUMBER

  1. A review of a method for dynamic load distribution, dynamical modeling, and explicit internal force control when two manipulators mutually lift and transport a rigid body object

    Energy Technology Data Exchange (ETDEWEB)

    Unseren, M.A.

    1997-04-20

    The paper reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restrict the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system.

  2. Graphical Tools for Linear Structural Equation Modeling

    Science.gov (United States)

    2014-06-01

    Figure 3a and its corresponding structural equations: Model 3. Z = UZ X = cZ + UX W = aX + UW Y = dZ + bW + eX + UY Using the do operation we obtain...the new set of equations: Z = UZ X = x W = aX + UW Y = dZ + bW + eX + UY The corresponding path diagram is displayed in Figure 3b. (Notice that paths...the following expectation for Y: E[Y |do(X = x)] = E[d · Z + b ·W + e · X + UY ] = d · E[Z] + b · E[W] + e · x + E[UY ] = d · E[ UZ ] + b · E[a · x

  3. Pre-Processing and Modeling Tools for Bigdata

    Directory of Open Access Journals (Sweden)

    Hashem Hadi

    2016-09-01

    Full Text Available Modeling tools and operators help the user / developer to identify the processing field on the top of the sequence and to send into the computing module only the data related to the requested result. The remaining data is not relevant and it will slow down the processing. The biggest challenge nowadays is to get high quality processing results with a reduced computing time and costs. To do so, we must review the processing sequence, by adding several modeling tools. The existing processing models do not take in consideration this aspect and focus on getting high calculation performances which will increase the computing time and costs. In this paper we provide a study of the main modeling tools for BigData and a new model based on pre-processing.

  4. An explicit-solvent conformation search method using open software

    Directory of Open Access Journals (Sweden)

    Kari Gaalswyk

    2016-05-01

    Full Text Available Computer modeling is a popular tool to identify the most-probable conformers of a molecule. Although the solvent can have a large effect on the stability of a conformation, many popular conformational search methods are only capable of describing molecules in the gas phase or with an implicit solvent model. We have developed a work-flow for performing a conformation search on explicitly-solvated molecules using open source software. This method uses replica exchange molecular dynamics (REMD to sample the conformational states of the molecule efficiently. Cluster analysis is used to identify the most probable conformations from the simulated trajectory. This work-flow was tested on drug molecules α-amanitin and cabergoline to illustrate its capabilities and effectiveness. The preferred conformations of these molecules in gas phase, implicit solvent, and explicit solvent are significantly different.

  5. Oceanic signals in rapid polar motion: results from a barotropic forward model with explicit consideration of self-attraction and loading effects

    Science.gov (United States)

    Schindelegger, Michael; Quinn, Katherine J.; Ponte, Rui M.

    2017-04-01

    Numerical modeling of non-tidal variations in ocean currents and bottom pressure has played a key role in closing the excitation budget of Earth's polar motion for a wide range of periodicities. Non-negligible discrepancies between observations and model accounts of pole position changes prevail, however, on sub-monthly time scales and call for examination of hydrodynamic effects usually omitted in general circulation models. Specifically, complete hydrodynamic cores must incorporate self-attraction and loading (SAL) feedbacks on redistributed water masses, effects that produces ocean bottom pressure perturbations of typically about 10% relative to the computed mass variations. Here, we report on a benchmark simulation with a near-global, barotropic forward model forced by wind stress, atmospheric pressure, and a properly calculated SAL term. The latter is obtained by decomposing ocean mass anomalies on a 30-minute grid into spherical harmonics at each time step and applying Love numbers to account for seafloor deformation and changed gravitational attraction. The increase in computational time at each time step is on the order of 50%. Preliminary results indicate that the explicit consideration of SAL in the forward runs increases the fidelity of modeled polar motion excitations, in particular on time scales shorter than 5 days as evident from cross spectral comparisons with geodetic excitation. Definite conclusions regarding the relevance of SAL in simulating rapid polar motion are, however, still hampered by the model's incomplete domain representation that excludes parts of the highly energetic Arctic Ocean.

  6. Mixed Quantum/Classical Method for Nonadiabatic Quantum Dynamics in Explicit Solvent Models: The ππ*/nπ* Decay of Thymine in Water as a Test Case.

    Science.gov (United States)

    Cerezo, Javier; Liu, Yanli; Lin, Na; Zhao, Xian; Improta, Roberto; Santoro, Fabrizio

    2018-01-03

    We present a novel mixed quantum classical dynamical method to include solvent effects on internal conversion (IC) processes. All the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics, while the motion of an explicit solvent model is described by an ensemble of classical trajectories. The mutual coupling of the solute and solvent dynamics is included within a mean-field framework and the quantum and classical equations of motions are solved simultaneously. As a test case we apply our method to the ultrafast ππ* → nπ* decay of thymine in water. Solvent dynamical response modifies IC yield already on the 50 fs time scale. This effect is due to water librational motions that stabilize the most populated state. Pure static disorder, that is, the existence of different solvent configurations when photoexcitation takes place, also has a remarkable impact on the dynamics.

  7. Model tool to describe chemical structures in XML format utilizing structural fragments and chemical ontology.

    Science.gov (United States)

    Sankar, Punnaivanam; Alain, Krief; Aghila, Gnanasekaran

    2010-05-24

    We have developed a model structure-editing tool, ChemEd, programmed in JAVA, which allows drawing chemical structures on a graphical user interface (GUI) by selecting appropriate structural fragments defined in a fragment library. The terms representing the structural fragments are organized in fragment ontology to provide a conceptual support. ChemEd describes the chemical structure in an XML document (ChemFul) with rich semantics explicitly encoding the details of the chemical bonding, the hybridization status, and the electron environment around each atom. The document can be further processed through suitable algorithms and with the support of external chemical ontologies to generate understandable reports about the functional groups present in the structure and their specific environment.

  8. Spatially explicit burden estimates of malaria in Tanzania: bayesian geostatistical modeling of the malaria indicator survey data.

    Directory of Open Access Journals (Sweden)

    Laura Gosoniu

    Full Text Available A national HIV/AIDS and malaria parasitological survey was carried out in Tanzania in 2007-2008. In this study the parasitological data were analyzed: i to identify climatic/environmental, socio-economic and interventions factors associated with child malaria risk and ii to produce a contemporary, high spatial resolution parasitaemia risk map of the country. Bayesian geostatistical models were fitted to assess the association between parasitaemia risk and its determinants. bayesian kriging was employed to predict malaria risk at unsampled locations across Tanzania and to obtain the uncertainty associated with the predictions. Markov chain Monte Carlo (MCMC simulation methods were employed for model fit and prediction. Parasitaemia risk estimates were linked to population data and the number of infected children at province level was calculated. Model validation indicated a high predictive ability of the geostatistical model, with 60.00% of the test locations within the 95% credible interval. The results indicate that older children are significantly more likely to test positive for malaria compared with younger children and living in urban areas and better-off households reduces the risk of infection. However, none of the environmental and climatic proxies or the intervention measures were significantly associated with the risk of parasitaemia. Low levels of malaria prevalence were estimated for Zanzibar island. The population-adjusted prevalence ranges from 0.29% in Kaskazini province (Zanzibar island to 18.65% in Mtwara region. The pattern of predicted malaria risk is similar with the previous maps based on historical data, although the estimates are lower. The predicted maps could be used by decision-makers to allocate resources and target interventions in the regions with highest burden of malaria in order to reduce the disease transmission in the country.

  9. Spatially explicit integrated modeling and economic valuation of climate driven land use change and its indirect effects.

    Science.gov (United States)

    Bateman, Ian; Agarwala, Matthew; Binner, Amy; Coombes, Emma; Day, Brett; Ferrini, Silvia; Fezzi, Carlo; Hutchins, Michael; Lovett, Andrew; Posen, Paulette

    2016-10-01

    We present an integrated model of the direct consequences of climate change on land use, and the indirect effects of induced land use change upon the natural environment. The model predicts climate-driven shifts in the profitability of alternative uses of agricultural land. Both the direct impact of climate change and the induced shift in land use patterns will cause secondary effects on the water environment, for which agriculture is the major source of diffuse pollution. We model the impact of changes in such pollution on riverine ecosystems showing that these will be spatially heterogeneous. Moreover, we consider further knock-on effects upon the recreational benefits derived from water environments, which we assess using revealed preference methods. This analysis permits a multi-layered examination of the economic consequences of climate change, assessing the sequence of impacts from climate change through farm gross margins, land use, water quality and recreation, both at the individual and catchment scale. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Spatially Explicit Modeling of Grazing Effect on Soil Organic Carbon Change in the Green River Basin, Wyoming

    Science.gov (United States)

    Li, Z.; Liu, S.; Tan, Z.

    2007-12-01

    Proper grazing can improve ecosystem production and enhance carbon sequestration, while overgrazing can lead to net emission of carbon into the atmosphere. It is challenging to quantify the impacts of grazing at a regional scale owing to the spatial and temporal changes of biophysical settings and land management practices. In this study, we quantified and evaluated impacts of grazing intensity on the dynamics of soil organic carbon (SOC) across the Green River Basin in southwestern Wyoming using a biogeochemical model (EDCM--erosion-deposition-carbon model) and remotely sensed data. We simulated responses of ecosystem carbon stocks (including SOC) and fluxes to various grazing scenarios. Results based on these simulations indicate that: (1) sagebrush-dominated shrublands accumulated less soil carbon than did grass-dominated area; (2) grazing could lead to a greater decrease in production and SOC in the shrubland than in the grassland under the same intensity and (3) a grazing intensity of 0.03 animal units per hectare could reduce SOC at a rate of 3.1 gC/m2/yr in shrublands, but SOC changed little in grasslands during 30 years of simulated responses. Our model simulations also show that conversion of shrubland to grassland can enhance soil carbon sequestration in the Green River Basin.

  11. Designer Modeling for Personalized Game Content Creation Tools

    DEFF Research Database (Denmark)

    Liapis, Antonios; Yannakakis, Georgios N.; Togelius, Julian

    2013-01-01

    With the growing use of automated content creation and computer-aided design tools in game development, there is potential for enhancing the design process through personalized interactions between the software and the game developer. This paper proposes designer modeling for capturing the designer......’s preferences, goals and processes from their interaction with a computer-aided design tool, and suggests methods and domains within game development where such a model can be applied. We describe how designer modeling could be integrated with current work on automated and mixed-initiative content creation......, and envision future directions which focus on personalizing the processes to a designer’s particular wishes....

  12. Simulation Tools for Electrical Machines Modelling: Teaching and ...

    African Journals Online (AJOL)

    Simulation tools are used both for research and teaching to allow a good comprehension of the systems under study before practical implementations. This paper illustrates the way MATLAB is used to model non-linearites in synchronous machine. The machine is modeled in rotor reference frame with currents as state ...

  13. The interaction of implicit learning, explicit hypothesis testing learning and implicit-to-explicit knowledge extraction.

    Science.gov (United States)

    Sun, Ron; Zhang, Xi; Slusarz, Paul; Mathews, Robert

    2007-01-01

    To further explore the interaction between the implicit and explicit learning processes in skill acquisition (which have been tackled before, e.g. in [Sun, R., Merrill, E., & Peterson, T. (2001). From implicit skill to explicit knowledge: A bottom-up model of skill learning. Cognitive Science, 25(2), 203-244; Sun, R., Slusarz, P., & Terry, C. (2005). The interaction of the explicit and the implicit in skill learning: A dual-process approach. Psychological Review, 112(1), 159-192]), this paper explores details of the interaction of different learning modes: implicit learning, explicit hypothesis testing learning, and implicit-to-explicit knowledge extraction. Contrary to the common tendency in the literature to study each type of learning in isolation, this paper highlights the interaction among them and various effects of the interaction on learning, including the synergy effect. This work advocates an integrated model of skill learning that takes into account both implicit and explicit learning processes; moreover, it also uniquely embodies a bottom-up (implicit-to-explicit) learning approach in addition to other types of learning. The paper shows that this model accounts for various effects in the human behavioural data from the psychological experiments with the process control task, in addition to accounting for other data in other psychological experiments (which has been reported elsewhere). The paper shows that to account for these effects, implicit learning, bottom-up implicit-to-explicit extraction and explicit hypothesis testing learning are all needed.

  14. New tools for linking human and earth system models: The Toolbox for Human-Earth System Interaction & Scaling (THESIS)

    Science.gov (United States)

    O'Neill, B. C.; Kauffman, B.; Lawrence, P.

    2016-12-01

    Integrated analysis of questions regarding land, water, and energy resources often requires integration of models of different types. One type of integration is between human and earth system models, since both societal and physical processes influence these resources. For example, human processes such as changes in population, economic conditions, and policies govern the demand for land, water and energy, while the interactions of these resources with physical systems determine their availability and environmental consequences. We have begun to develop and use a toolkit for linking human and earth system models called the Toolbox for Human-Earth System Integration and Scaling (THESIS). THESIS consists of models and software tools to translate, scale, and synthesize information from and between human system models and earth system models (ESMs), with initial application to linking the NCAR integrated assessment model, iPETS, with the NCAR earth system model, CESM. Initial development is focused on urban areas and agriculture, sectors that are both explicitly represented in both CESM and iPETS. Tools are being made available to the community as they are completed (see https://www2.cgd.ucar.edu/sections/tss/iam/THESIS_tools). We discuss four general types of functions that THESIS tools serve (Spatial Distribution, Spatial Properties, Consistency, and Outcome Evaluation). Tools are designed to be modular and can be combined in order to carry out more complex analyses. We illustrate their application to both the exposure of population to climate extremes and to the evaluation of climate impacts on the agriculture sector. For example, projecting exposure to climate extremes involves use of THESIS tools for spatial population, spatial urban land cover, the characteristics of both, and a tool to bring urban climate information together with spatial population information. Development of THESIS tools is continuing and open to the research community.

  15. Cocrystal solubility product analysis - Dual concentration-pH mass action model not dependent on explicit solubility equations.

    Science.gov (United States)

    Avdeef, Alex

    2017-12-15

    A novel general computational approach is described to address many aspects of cocrystal (CC) solubility product (Ksp) determination of drug substances. The CC analysis program, pDISOL-X, was developed and validated with published model systems of various acid-base combinations of active pharmaceutical ingredients (APIs) and coformers: (i) carbamazepine cocrystal systems with 4-aminobenzoic acid, cinnamic acid, saccharin, and salicylic acid, (ii) for indomethacin with saccharin, (iii) for nevirapine with maleic acid, saccharin, and salicylic acid, and (iv) for gabapentin with 3-hydroxybenzoic acid. In all systems but gabapentin, the coformer is much more soluble than the API. The model systems selected are those with available published dual concentration-pH data, one set for the API and one set for the coformer, generally measured at eutectic points (thermodynamically-stable three phases: solution, cocrystal, and crystalline API or coformer). The carbamazepine-cinnamic acid CC showed a substantial elevation in the API equilibrium concentration above pH5, consistent with the formation of a complex between carbamazepine and cinnamate anion. The analysis of the gabapentin:3-hydroxybenzoic acid 1:1 CC system indicated four zones of solid suspensions: coformer (pH5.62). The general approach allows for testing of many possible equilibrium models, including those comprising drug-coformer complexation. The program calculates the ionic strength at each pH. From this, the equilibrium constants are adjusted for activity effects, based on the Stokes-Robinson hydration theory. The complete speciation analysis of the CC systems may provide useful insights into pH-sensitive dissolution effects that could potentially influence bioavailability. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Modeling surgical tool selection patterns as a "traveling salesman problem" for optimizing a modular surgical tool system.

    Science.gov (United States)

    Nelson, Carl A; Miller, David J; Oleynikov, Dmitry

    2008-01-01

    As modular systems come into the forefront of robotic telesurgery, streamlining the process of selecting surgical tools becomes an important consideration. This paper presents a method for optimal queuing of tools in modular surgical tool systems, based on patterns in tool-use sequences, in order to minimize time spent changing tools. The solution approach is to model the set of tools as a graph, with tool-change frequency expressed as edge weights in the graph, and to solve the Traveling Salesman Problem for the graph. In a set of simulations, this method has shown superior performance at optimizing tool arrangements for streamlining surgical procedures.

  17. Lightweight approach to model traceability in a CASE tool

    Science.gov (United States)

    Vileiniskis, Tomas; Skersys, Tomas; Pavalkis, Saulius; Butleris, Rimantas; Butkiene, Rita

    2017-07-01

    A term "model-driven" is not at all a new buzzword within the ranks of system development community. Nevertheless, the ever increasing complexity of model-driven approaches keeps fueling all kinds of discussions around this paradigm and pushes researchers forward to research and develop new and more effective ways to system development. With the increasing complexity, model traceability, and model management as a whole, becomes indispensable activities of model-driven system development process. The main goal of this paper is to present a conceptual design and implementation of a practical lightweight approach to model traceability in a CASE tool.

  18. Evaluating effects of Everglades restoration on American crocodile populations in south Florida using a spatially-explicit, stage-based population model

    Science.gov (United States)

    Green, Timothy W.; Slone, Daniel H.; Swain, Eric D.; Cherkiss, Michael S.; Lohmann, Melinda; Mazzotti, Frank J.; Rice, Kenneth G.

    2014-01-01

    The distribution and abundance of the American crocodile (Crocodylus acutus) in the Florida Everglades is dependent on the timing, amount, and location of freshwater flow. One of the goals of the Comprehensive Everglades Restoration Plan (CERP) is to restore historic freshwater flows to American crocodile habitat throughout the Everglades. To predict the impacts on the crocodile population from planned restoration activities, we created a stage-based spatially explicit crocodile population model that incorporated regional hydrology models and American crocodile research and monitoring data. Growth and survival were influenced by salinity, water depth, and density-dependent interactions. A stage-structured spatial model was used with discrete spatial convolution to direct crocodiles toward attractive sources where conditions were favorable. The model predicted that CERP would have both positive and negative impacts on American crocodile growth, survival, and distribution. Overall, crocodile populations across south Florida were predicted to decrease approximately 3 % with the implementation of CERP compared to future conditions without restoration, but local increases up to 30 % occurred in the Joe Bay area near Taylor Slough, and local decreases up to 30 % occurred in the vicinity of Buttonwood Canal due to changes in salinity and freshwater flows.

  19. Business intelligence tools for radiology: creating a prototype model using open-source tools.

    Science.gov (United States)

    Prevedello, Luciano M; Andriole, Katherine P; Hanson, Richard; Kelly, Pauline; Khorasani, Ramin

    2010-04-01

    Digital radiology departments could benefit from the ability to integrate and visualize data (e.g. information reflecting complex workflow states) from all of their imaging and information management systems in one composite presentation view. Leveraging data warehousing tools developed in the business world may be one way to achieve this capability. In total, the concept of managing the information available in this data repository is known as Business Intelligence or BI. This paper describes the concepts used in Business Intelligence, their importance to modern Radiology, and the steps used in the creation of a prototype model of a data warehouse for BI using open-source tools.

  20. Hybrid Neural Network Approach Based Tool for the Modelling of Photovoltaic Panels

    Directory of Open Access Journals (Sweden)

    Antonino Laudani

    2015-01-01

    Full Text Available A hybrid neural network approach based tool for identifying the photovoltaic one-diode model is presented. The generalization capabilities of neural networks are used together with the robustness of the reduced form of one-diode model. Indeed, from the studies performed by the authors and the works present in the literature, it was found that a direct computation of the five parameters via multiple inputs and multiple outputs neural network is a very difficult task. The reduced form consists in a series of explicit formulae for the support to the neural network that, in our case, is aimed at predicting just two parameters among the five ones identifying the model: the other three parameters are computed by reduced form. The present hybrid approach is efficient from the computational cost point of view and accurate in the estimation of the five parameters. It constitutes a complete and extremely easy tool suitable to be implemented in a microcontroller based architecture. Validations are made on about 10000 PV panels belonging to the California Energy Commission database.

  1. Surface O3 photochemistry over the South China Sea: Application of a near-explicit chemical mechanism box model.

    Science.gov (United States)

    Wang, Yu; Guo, Hai; Zou, Shichun; Lyu, Xiaopu; Ling, Zhenhao; Cheng, Hairong; Zeren, Yangzong

    2017-11-22

    A systematic field measurement was conducted at an island site (Wanshan Island, WSI) over the South China Sea (SCS) in autumn 2013. It was observed that mixing ratios of O3 and its precursors (such as volatile organic compounds (VOCs), nitrogen oxides (NOx = NO + NO2) and carbon monoxide (CO)) showed significant differences on non-episode days and episode days. Additional knowledge was gained when a photochemical box model incorporating the Master Chemical Mechanism (PBM-MCM) was applied to further investigate the differences/similarities of O3 photochemistry between non-episode and episode days, in terms of O3-precursor relationship, atmospheric photochemical reactivity and O3 production. The simulation results revealed that, from non-O3 episode days to episode days, 1) O3 production changed from both VOC and NOx-limited (transition regime) to VOC-limited; 2) OH radicals increased and photochemical reaction cycling processes accelerated; and 3) both O3 production and destruction rates increased significantly, resulting in an elevated net O3 production over the SCS. The findings indicate the complexity of O3 pollution over the SCS. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Exploring a multi-scale method for molecular simulation in continuum solvent model: Explicit simulation of continuum solvent as an incompressible fluid

    Science.gov (United States)

    Xiao, Li; Luo, Ray

    2017-12-01

    We explored a multi-scale algorithm for the Poisson-Boltzmann continuum solvent model for more robust simulations of biomolecules. In this method, the continuum solvent/solute interface is explicitly simulated with a numerical fluid dynamics procedure, which is tightly coupled to the solute molecular dynamics simulation. There are multiple benefits to adopt such a strategy as presented below. At this stage of the development, only nonelectrostatic interactions, i.e., van der Waals and hydrophobic interactions, are included in the algorithm to assess the quality of the solvent-solute interface generated by the new method. Nevertheless, numerical challenges exist in accurately interpolating the highly nonlinear van der Waals term when solving the finite-difference fluid dynamics equations. We were able to bypass the challenge rigorously by merging the van der Waals potential and pressure together when solving the fluid dynamics equations and by considering its contribution in the free-boundary condition analytically. The multi-scale simulation method was first validated by reproducing the solute-solvent interface of a single atom with analytical solution. Next, we performed the relaxation simulation of a restrained symmetrical monomer and observed a symmetrical solvent interface at equilibrium with detailed surface features resembling those found on the solvent excluded surface. Four typical small molecular complexes were then tested, both volume and force balancing analyses showing that these simple complexes can reach equilibrium within the simulation time window. Finally, we studied the quality of the multi-scale solute-solvent interfaces for the four tested dimer complexes and found that they agree well with the boundaries as sampled in the explicit water simulations.

  3. Modeling and Simulation Tools: From Systems Biology to Systems Medicine.

    Science.gov (United States)

    Olivier, Brett G; Swat, Maciej J; Moné, Martijn J

    2016-01-01

    Modeling is an integral component of modern biology. In this chapter we look into the role of the model, as it pertains to Systems Medicine, and the software that is required to instantiate and run it. We do this by comparing the development, implementation, and characteristics of tools that have been developed to work with two divergent methodologies: Systems Biology and Pharmacometrics. From the Systems Biology perspective we consider the concept of "Software as a Medical Device" and what this may imply for the migration of research-oriented, simulation software into the domain of human health.In our second perspective, we see how in practice hundreds of computational tools already accompany drug discovery and development at every stage of the process. Standardized exchange formats are required to streamline the model exchange between tools, which would minimize translation errors and reduce the required time. With the emergence, almost 15 years ago, of the SBML standard, a large part of the domain of interest is already covered and models can be shared and passed from software to software without recoding them. Until recently the last stage of the process, the pharmacometric analysis used in clinical studies carried out on subject populations, lacked such an exchange medium. We describe a new emerging exchange format in Pharmacometrics which covers the non-linear mixed effects models, the standard statistical model type used in this area. By interfacing these two formats the entire domain can be covered by complementary standards and subsequently the according tools.

  4. Risk Assessment in Fractured Clayey Tills - Which Modeling Tools?

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Bjerg, Poul Løgstrup; Binning, Philip John

    2012-01-01

    The article presents different tools available for risk assessment in fractured clayey tills and their advantages and limitations are discussed. Because of the complex processes occurring during contaminant transport through fractured media, the development of simple practical tools for risk...... assessment is challenging and the inclusion of the relevant processes is difficult. Furthermore the lack of long-term monitoring data prevents from verifying the accuracy of the different conceptual models. Further investigations based on long-term data and numerical modeling are needed to accurately...

  5. Static Stiffness Modeling of Parallel Kinematics Machine Tool Joints

    Directory of Open Access Journals (Sweden)

    O. K. Akmaev

    2015-09-01

    Full Text Available The possible variants of an original parallel kinematics machine-tool structure are explored in this article. A new Hooke's universal joint design based on needle roller bearings with the ability of a preload setting is proposed. The bearing stiffness modeling is carried out using a variety of methods. The elastic deformation modeling of a Hook’s joint and a spherical rolling joint have been developed to assess the possibility of using these joints in machine tools with parallel kinematics.

  6. User Assistance Characteristics of the USE Model Checking Tool

    Directory of Open Access Journals (Sweden)

    Frank Hilken

    2017-01-01

    Full Text Available The Unified Modeling Language (UML is a widely used general purpose modeling language. Together with the Object Constraint Language (OCL, formal models can be described by defining the structure and behavior with UML and additional OCL constraints. In the development process for formal models, it is important to make sure that these models are (a correct, i.e. consistent and complete, and (b testable in the sense that the developer is able to interactively check model properties. The USE tool (UML-based Specification Environment allows both characteristics to be studied. We demonstrate how the tool supports modelers to analyze, validate and verify UML and OCL models via the use of several graphical means that assist the modeler in interpreting and visualizing formal model descriptions. In particular, we discuss how the so-called USE model validator plugin is integrated into the USE environment in order to allow non domain experts to use it and construct object models that help to verify properties like model consistency.

  7. Open source Modeling and optimization tools for Planning

    Energy Technology Data Exchange (ETDEWEB)

    Peles, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-02-10

    Open source modeling and optimization tools for planning The existing tools and software used for planning and analysis in California are either expensive, difficult to use, or not generally accessible to a large number of participants. These limitations restrict the availability of participants for larger scale energy and grid studies in the state. The proposed initiative would build upon federal and state investments in open source software, and create and improve open source tools for use in the state planning and analysis activities. Computational analysis and simulation frameworks in development at national labs and universities can be brought forward to complement existing tools. An open source platform would provide a path for novel techniques and strategies to be brought into the larger community and reviewed by a broad set of stakeholders.

  8. Using the IEA ETSAP modelling tools for Denmark

    DEFF Research Database (Denmark)

    Grohnheit, Poul Erik

    , Environment and Health (CEEH), starting from January 2007. This report summarises the activities under ETSAP Annex X and related project, emphasising the development of modelling tools that will be useful for modelling the Danish energy system. It is also a status report for the development of a model...... signed the agreement and contributed to some early annexes. This project is motivated by an invitation to participate in ETSAP Annex X, "Global Energy Systems and Common Analyses: Climate friendly, Secure and Productive Energy Systems" for the period 2005 to 2007. The main activity is semi-annual...... workshops focusing on presentations of model analyses and use of the ETSAP' tools (the MARKAL/TIMES family of models). The project was also planned to benefit from the EU project ”NEEDS - New Energy Externalities Developments for Sustainability. ETSAP is contributing to a part of NEEDS that develops...

  9. A general thermal model of machine tool spindle

    Directory of Open Access Journals (Sweden)

    Yanfang Dong

    2017-01-01

    Full Text Available As the core component of machine tool, the thermal characteristics of the spindle have a significant influence on machine tool running status. Lack of an accurate model of the spindle system, particularly the model of load–deformation coefficient between the bearing rolling elements and rings, severely limits the thermal error analytic precision of the spindle. In this article, bearing internal loads, especially the function relationships between the principal curvature difference F(ρ and auxiliary parameter nδ, semi-major axis a, and semi-minor axis b, have been determined; furthermore, high-precision heat generation combining the heat sinks in the spindle system is calculated; finally, an accurate thermal model of the spindle was established. Moreover, a conventional spindle with embedded fiber Bragg grating temperature sensors has been developed. By comparing the experiment results with simulation, it indicates that the model has good accuracy, which verifies the reliability of the modeling process.

  10. VCMM: a visual tool for continuum molecular modeling.

    Science.gov (United States)

    Bai, Shiyang; Lu, Benzhuo

    2014-05-01

    This paper describes the design and function of a visualization tool, VCMM, for visualizing and analyzing data, and interfacing solvers for generic continuum molecular modeling. In particular, an emphasis of the program is to treat the data set based on unstructured mesh as used in finite/boundary element simulations, which largely enhances the capabilities of current visualization tools in this area that only support structured mesh. VCMM is segmented into molecular, meshing and numerical modules. The capabilities of molecular module include molecular visualization and force field assignment. Meshing module contains mesh generation, analysis and visualization tools. Numerical module currently provides a few finite/boundary element solvers of continuum molecular modeling, and contains several common visualization tools for the numerical result such as line and plane interpolations, surface probing, volume rendering and stream rendering. Three modules can exchange data with each other and carry out a complete process of modeling. Interfaces are also designed in order to facilitate usage of other mesh generation tools and numerical solvers. We develop a technique to accelerate data retrieval and have combined many graphical techniques in visualization. VCMM is highly extensible, and users can obtain more powerful functions by introducing relevant plug-ins. VCMM can also be useful in other fields such as computational quantum chemistry, image processing, and material science. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Designing tools for oil exploration using nuclear modeling

    Science.gov (United States)

    Mauborgne, Marie-Laure; Allioli, Françoise; Manclossi, Mauro; Nicoletti, Luisa; Stoller, Chris; Evans, Mike

    2017-09-01

    When designing nuclear tools for oil exploration, one of the first steps is typically nuclear modeling for concept evaluation and initial characterization. Having an accurate model, including the availability of accurate cross sections, is essential to reduce or avoid time consuming and costly design iterations. During tool response characterization, modeling is benchmarked with experimental data and then used to complement and to expand the database to make it more detailed and inclusive of more measurement environments which are difficult or impossible to reproduce in the laboratory. We present comparisons of our modeling results obtained using the ENDF/B-VI and ENDF/B-VII cross section data bases, focusing on the response to a few elements found in the tool, borehole and subsurface formation. For neutron-induced inelastic and capture gamma ray spectroscopy, major obstacles may be caused by missing or inaccurate cross sections for essential materials. We show examples of the benchmarking of modeling results against experimental data obtained during tool characterization and discuss observed discrepancies.

  12. Designing tools for oil exploration using nuclear modeling

    Directory of Open Access Journals (Sweden)

    Mauborgne Marie-Laure

    2017-01-01

    Full Text Available When designing nuclear tools for oil exploration, one of the first steps is typically nuclear modeling for concept evaluation and initial characterization. Having an accurate model, including the availability of accurate cross sections, is essential to reduce or avoid time consuming and costly design iterations. During tool response characterization, modeling is benchmarked with experimental data and then used to complement and to expand the database to make it more detailed and inclusive of more measurement environments which are difficult or impossible to reproduce in the laboratory. We present comparisons of our modeling results obtained using the ENDF/B-VI and ENDF/B-VII cross section data bases, focusing on the response to a few elements found in the tool, borehole and subsurface formation. For neutron-induced inelastic and capture gamma ray spectroscopy, major obstacles may be caused by missing or inaccurate cross sections for essential materials. We show examples of the benchmarking of modeling results against experimental data obtained during tool characterization and discuss observed discrepancies.

  13. Explicit Instruction Elements in Core Reading Programs

    OpenAIRE

    Child, Angela R.

    2012-01-01

    Classroom teachers are provided instructional recommendations for teaching reading from their adopted core reading programs (CRPs). Explicit instruction elements or what is also called instructional moves, including direct explanation, modeling, guided practice, independent practice, discussion, feedback, and monitoring, were examined within CRP reading lessons. This study sought to answer the question: What elements of explicit instruction or instructional moves are included in the five most...

  14. HMMEditor: a visual editing tool for profile hidden Markov model

    Directory of Open Access Journals (Sweden)

    Cheng Jianlin

    2008-03-01

    Full Text Available Abstract Background Profile Hidden Markov Model (HMM is a powerful statistical model to represent a family of DNA, RNA, and protein sequences. Profile HMM has been widely used in bioinformatics research such as sequence alignment, gene structure prediction, motif identification, protein structure prediction, and biological database search. However, few comprehensive, visual editing tools for profile HMM are publicly available. Results We develop a visual editor for profile Hidden Markov Models (HMMEditor. HMMEditor can visualize the profile HMM architecture, transition probabilities, and emission probabilities. Moreover, it provides functions to edit and save HMM and parameters. Furthermore, HMMEditor allows users to align a sequence against the profile HMM and to visualize the corresponding Viterbi path. Conclusion HMMEditor provides a set of unique functions to visualize and edit a profile HMM. It is a useful tool for biological sequence analysis and modeling. Both HMMEditor software and web service are freely available.

  15. Accessing Curriculum Through Technology Tools (ACTTT): A Model Development Project

    Science.gov (United States)

    Daytner, Katrina M.; Johanson, Joyce; Clark, Letha; Robinson, Linda

    2012-01-01

    Accessing Curriculum Through Technology Tools (ACTTT), a project funded by the U.S. Office of Special Education Programs (OSEP), developed and tested a model designed to allow children in early elementary school, including those "at risk" and with disabilities, to better access, participate in, and benefit from the general curriculum.…

  16. Integrated landscape/hydrologic modeling tool for semiarid watersheds

    Science.gov (United States)

    Mariano Hernandez; Scott N. Miller

    2000-01-01

    An integrated hydrologic modeling/watershed assessment tool is being developed to aid in determining the susceptibility of semiarid landscapes to natural and human-induced changes across a range of scales. Watershed processes are by definition spatially distributed and are highly variable through time, and this approach is designed to account for their spatial and...

  17. Molecular Modeling: A Powerful Tool for Drug Design and Molecular ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 5. Molecular Modeling: A Powerful Tool for Drug Design and Molecular Docking. Rama Rao Nadendla. General Article Volume 9 Issue 5 May 2004 pp 51-60. Fulltext. Click here to view fulltext PDF. Permanent link:

  18. AgMIP Training in Multiple Crop Models and Tools

    Science.gov (United States)

    Boote, Kenneth J.; Porter, Cheryl H.; Hargreaves, John; Hoogenboom, Gerrit; Thornburn, Peter; Mutter, Carolyn

    2015-01-01

    The Agricultural Model Intercomparison and Improvement Project (AgMIP) has the goal of using multiple crop models to evaluate climate impacts on agricultural production and food security in developed and developing countries. There are several major limitations that must be overcome to achieve this goal, including the need to train AgMIP regional research team (RRT) crop modelers to use models other than the ones they are currently familiar with, plus the need to harmonize and interconvert the disparate input file formats used for the various models. Two activities were followed to address these shortcomings among AgMIP RRTs to enable them to use multiple models to evaluate climate impacts on crop production and food security. We designed and conducted courses in which participants trained on two different sets of crop models, with emphasis on the model of least experience. In a second activity, the AgMIP IT group created templates for inputting data on soils, management, weather, and crops into AgMIP harmonized databases, and developed translation tools for converting the harmonized data into files that are ready for multiple crop model simulations. The strategies for creating and conducting the multi-model course and developing entry and translation tools are reviewed in this chapter.

  19. Greenhouse gases from wastewater treatment - A review of modelling tools.

    Science.gov (United States)

    Mannina, Giorgio; Ekama, George; Caniani, Donatella; Cosenza, Alida; Esposito, Giovanni; Gori, Riccardo; Garrido-Baserba, Manel; Rosso, Diego; Olsson, Gustaf

    2016-05-01

    Nitrous oxide, carbon dioxide and methane are greenhouse gases (GHG) emitted from wastewater treatment that contribute to its carbon footprint. As a result of the increasing awareness of GHG emissions from wastewater treatment plants (WWTPs), new modelling, design, and operational tools have been developed to address and reduce GHG emissions at the plant-wide scale and beyond. This paper reviews the state-of-the-art and the recently developed tools used to understand and manage GHG emissions from WWTPs, and discusses open problems and research gaps. The literature review reveals that knowledge on the processes related to N2O formation, especially due to autotrophic biomass, is still incomplete. The literature review shows also that a plant-wide modelling approach that includes GHG is the best option for the understanding how to reduce the carbon footprint of WWTPs. Indeed, several studies have confirmed that a wide vision of the WWPTs has to be considered in order to make them more sustainable as possible. Mechanistic dynamic models were demonstrated as the most comprehensive and reliable tools for GHG assessment. Very few plant-wide GHG modelling studies have been applied to real WWTPs due to the huge difficulties related to data availability and the model complexity. For further improvement in GHG plant-wide modelling and to favour its use at large real scale, knowledge of the mechanisms involved in GHG formation and release, and data acquisition must be enhanced. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. The Role of Explicit and Implicit Self-Esteem in Peer Modeling of Palatable Food Intake: A Study on Social Media Interaction among Youngsters

    Science.gov (United States)

    Bevelander, Kirsten E.; Anschütz, Doeschka J.; Creemers, Daan H. M.; Kleinjan, Marloes; Engels, Rutger C. M. E.

    2013-01-01

    Objective This experimental study investigated the impact of peers on palatable food intake of youngsters within a social media setting. To determine whether this effect was moderated by self-esteem, the present study examined the roles of global explicit self-esteem (ESE), body esteem (BE) and implicit self-esteem (ISE). Methods Participants (N = 118; 38.1% boys; M age 11.14±.79) were asked to play a computer game while they believed to interact online with a same-sex normal-weight remote confederate (i.e., instructed peer) who ate either nothing, a small or large amount of candy. Results Participants modeled the candy intake of peers via a social media interaction, but this was qualified by their self-esteem. Participants with higher ISE adjusted their candy intake to that of a peer more closely than those with lower ISE when the confederate ate nothing compared to when eating a modest (β = .26, p = .05) or considerable amount of candy (kcal) (β = .32, p = .001). In contrast, participants with lower BE modeled peer intake more than those with higher BE when eating nothing compared to a considerable amount of candy (kcal) (β = .21, p = .02); ESE did not moderate social modeling behavior. In addition, participants with higher discrepant or “damaged” self-esteem (i.e., high ISE and low ESE) modeled peer intake more when the peer ate nothing or a modest amount compared to a substantial amount of candy (kcal) (β = −.24, p = .004; β = −.26, psocial media interaction. Those with lower body esteem or damaged self-esteem may be more at risk to peer influences on food intake. PMID:24015251

  1. The role of explicit and implicit self-esteem in peer modeling of palatable food intake: a study on social media interaction among youngsters.

    Directory of Open Access Journals (Sweden)

    Kirsten E Bevelander

    Full Text Available OBJECTIVE: This experimental study investigated the impact of peers on palatable food intake of youngsters within a social media setting. To determine whether this effect was moderated by self-esteem, the present study examined the roles of global explicit self-esteem (ESE, body esteem (BE and implicit self-esteem (ISE. METHODS: Participants (N = 118; 38.1% boys; M age 11.14±.79 were asked to play a computer game while they believed to interact online with a same-sex normal-weight remote confederate (i.e., instructed peer who ate either nothing, a small or large amount of candy. RESULTS: Participants modeled the candy intake of peers via a social media interaction, but this was qualified by their self-esteem. Participants with higher ISE adjusted their candy intake to that of a peer more closely than those with lower ISE when the confederate ate nothing compared to when eating a modest (β = .26, p = .05 or considerable amount of candy (kcal (β = .32, p = .001. In contrast, participants with lower BE modeled peer intake more than those with higher BE when eating nothing compared to a considerable amount of candy (kcal (β = .21, p = .02; ESE did not moderate social modeling behavior. In addition, participants with higher discrepant or "damaged" self-esteem (i.e., high ISE and low ESE modeled peer intake more when the peer ate nothing or a modest amount compared to a substantial amount of candy (kcal (β = -.24, p = .004; β = -.26, p<.0001, respectively. CONCLUSION: Youngsters conform to the amount of palatable food eaten by peers through social media interaction. Those with lower body esteem or damaged self-esteem may be more at risk to peer influences on food intake.

  2. The role of explicit and implicit self-esteem in peer modeling of palatable food intake: a study on social media interaction among youngsters.

    Science.gov (United States)

    Bevelander, Kirsten E; Anschütz, Doeschka J; Creemers, Daan H M; Kleinjan, Marloes; Engels, Rutger C M E

    2013-01-01

    This experimental study investigated the impact of peers on palatable food intake of youngsters within a social media setting. To determine whether this effect was moderated by self-esteem, the present study examined the roles of global explicit self-esteem (ESE), body esteem (BE) and implicit self-esteem (ISE). Participants (N = 118; 38.1% boys; M age 11.14±.79) were asked to play a computer game while they believed to interact online with a same-sex normal-weight remote confederate (i.e., instructed peer) who ate either nothing, a small or large amount of candy. Participants modeled the candy intake of peers via a social media interaction, but this was qualified by their self-esteem. Participants with higher ISE adjusted their candy intake to that of a peer more closely than those with lower ISE when the confederate ate nothing compared to when eating a modest (β = .26, p = .05) or considerable amount of candy (kcal) (β = .32, p = .001). In contrast, participants with lower BE modeled peer intake more than those with higher BE when eating nothing compared to a considerable amount of candy (kcal) (β = .21, p = .02); ESE did not moderate social modeling behavior. In addition, participants with higher discrepant or "damaged" self-esteem (i.e., high ISE and low ESE) modeled peer intake more when the peer ate nothing or a modest amount compared to a substantial amount of candy (kcal) (β = -.24, p = .004; β = -.26, psocial media interaction. Those with lower body esteem or damaged self-esteem may be more at risk to peer influences on food intake.

  3. High accuracy navigation information estimation for inertial system using the multi-model EKF fusing adams explicit formula applied to underwater gliders.

    Science.gov (United States)

    Huang, Haoqian; Chen, Xiyuan; Zhang, Bo; Wang, Jian

    2017-01-01

    The underwater navigation system, mainly consisting of MEMS inertial sensors, is a key technology for the wide application of underwater gliders and plays an important role in achieving high accuracy navigation and positioning for a long time of period. However, the navigation errors will accumulate over time because of the inherent errors of inertial sensors, especially for MEMS grade IMU (Inertial Measurement Unit) generally used in gliders. The dead reckoning module is added to compensate the errors. In the complicated underwater environment, the performance of MEMS sensors is degraded sharply and the errors will become much larger. It is difficult to establish the accurate and fixed error model for the inertial sensor. Therefore, it is very hard to improve the accuracy of navigation information calculated by sensors. In order to solve the problem mentioned, the more suitable filter which integrates the multi-model method with an EKF approach can be designed according to different error models to give the optimal estimation for the state. The key parameters of error models can be used to determine the corresponding filter. The Adams explicit formula which has an advantage of high precision prediction is simultaneously fused into the above filter to achieve the much more improvement in attitudes estimation accuracy. The proposed algorithm has been proved through theory analyses and has been tested by both vehicle experiments and lake trials. Results show that the proposed method has better accuracy and effectiveness in terms of attitudes estimation compared with other methods mentioned in the paper for inertial navigation applied to underwater gliders. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  4. Hydro-glaciological modeling in the Upper Maipo River basin, extratropical Andes Cordillera, with explicit representation of debris-covered glaciers.

    Science.gov (United States)

    McPhee, J. P.; Castillo, Y.; Escobar, M.; Pellicciotti, F.

    2014-12-01

    In this work we improve and calibrate a hydro-glaciological model based on a simplified energy balance approach using the WEAP modeling platform for two catchments in the headwaters of the Maipo River Basin, in the Andes Mountains of Central Chile. The Morales Creek catchment includes the San Francisco glacier, a clean glacier occupying 7% of the catchment area. The Pirámide catchment holds the debris-covered Pirámide Glacier, which covers 20% of the catchment area. Detailed field measurements have been carried out on both glaciers to characterize their melt and meteorological regimes. We calibrate an Enhanced Temperature Index melt model against ablation stakes and runoff measurements, and obtain clear differences between the optimal parameters for the clean and debris-covered glaciers. Calibrate melt threshold temperatures are 0,25 and 0,5ºC for the clean and debris-covered glaciers, respectively, while the fraction of net shortwave radiation employed for melting is 90 and 83% for clean and debris-covered glaciers, respectively. These results are coherent with an insulating effect of the debris cover at the Pirámide glacier. The hydrologic contribution of ice melt for the clean, San Francisco glacier is equivalent to 32% of total runoff measured at the Morales Creek outlet during the simulation period; on the other hand, ice melt accounts for 83% of total runoff estimated at the outlet of the Pirámide catchment over the same period. These results are part on an ongoing effort aimed at quantifying cryospheric contribution to the hydrology of the Maipo River basin, one of the key river basins in Chile, on the face of accelerated climate change, and is the first documented work to explicitly include debris-covered glaciers in a context of basin-wide hydrological modeling.

  5. Making the Tacit Explicit

    DEFF Research Database (Denmark)

    Blasco, Maribel

    2015-01-01

    The article proposes an approach, broadly inspired by culturally inclusive pedagogy, to facilitate international student academic adaptation based on rendering tacit aspects of local learning cultures explicit to international full degree students, rather than adapting them. Preliminary findings...... are presented from a focus group-based exploratory study of international student experiences at different stages of their studies at a Danish business school, one of Denmark’s most international universities. The data show how a major source of confusion for these students has to do with the tacit logics...... and expectations that shape how the formal steps of the learning cycle are understood and enacted locally, notably how learning and assessment moments are defined and related to one another. Theoretically, the article draws on tacit knowledge and sense-making theories to analyse student narratives...

  6. Open Tools for Integrated Modelling to Understand SDG development - The OPTIMUS program

    Science.gov (United States)

    Howells, Mark; Zepeda, Eduardo; Rogner, H. Holger; Sanchez, Marco; Roehrl, Alexander; Cicowiez, Matrin; Mentis, Dimitris; Korkevelos, Alexandros; Taliotis, Constantinos; Broad, Oliver; Alfstad, Thomas

    2016-04-01

    The recently adopted Sustainable Development Goals (SDGs) - a set of 17 measurable and time-bound goals with 169 associated targets for 2030 - are highly inclusive challenges before the world community ranging from eliminating poverty to human rights, inequality, a secure world and protection of the environment. Each individual goal or target by themselves present enormous tasks, taken together they are overwhelming. There strong and weak interlinkages, hence trade-offs and complementarities among goals and targets. Some targets may affect several goals while other goals and targets may conflict or be mutually exclusive (Ref). Meeting each of these requires the judicious exploitation of resource, with energy playing an important role. Such complexity demands to be addressed in an integrated way using systems analysis tools to support informed policy formulation, planning, allocation of scarce resources, monitoring progress, effectiveness and review at different scales. There is no one size fits all methodology that conceivably could include all goal and targets simultaneously. But there are methodologies encapsulating critical subsets of the goal and targets with strong interlinkages with a 'soft' reflection on the weak interlinkages. Universal food security or sustainable energy for all inherently support goals and targets on human rights and equality but possibly at the cost of biodiversity or desertification. Integrated analysis and planning tools are not yet commonplace at national universities - or indeed in many policy making organs. What is needed is a fundamental realignment of institutions and integrations of their planning processes and decision making. We introduce a series of open source tools to support the SDG planning and implementation process. The Global User-friendly CLEW Open Source (GLUCOSE) tool optimizes resource interactions and constraints; The Global Electrification Tool kit (GETit) provides the first global spatially explicit

  7. Research progress of machine tool thermal error modeling technology

    Directory of Open Access Journals (Sweden)

    Qianjian GUO

    2015-08-01

    Full Text Available During cutting, machine tools are influenced by different heat sources, which induces machine thermal deformation, deviation and thermal error. In different machine errors, thermal error accounts for 40%~70% of total machine errors, which is the main influence factor of machining accuracy. In order to reduce machine thermal error and improve machining precision, there are mainly 3 ways at present: 1 Improving machine thermal stiffness by optimal design of machine structure; 2 Separating heat sources from machine tools; 3 Thermal error compensation, which reduces the influence of thermal distortions by predicting and compensating measures. In order to compensate thermal errors, thermal error modeling is the premise and foundation. Therefore, thermal error modeling technology is introduced in this paper firstly, and its recent development both at home and abroad is analyzed. The main obstacles in thermal error modeling field at present are summerized, and the future of the technology are presented.

  8. Scenario Evaluator for Electrical Resistivity survey pre-modeling tool

    Science.gov (United States)

    Terry, Neil; Day-Lewis, Frederick D.; Robinson, Judith L.; Slater, Lee D.; Halford, Keith J.; Binley, Andrew; Lane, John W.; Werkema, Dale

    2017-01-01

    Geophysical tools have much to offer users in environmental, water resource, and geotechnical fields; however, techniques such as electrical resistivity imaging (ERI) are often oversold and/or overinterpreted due to a lack of understanding of the limitations of the techniques, such as the appropriate depth intervals or resolution of the methods. The relationship between ERI data and resistivity is nonlinear; therefore, these limitations depend on site conditions and survey design and are best assessed through forward and inverse modeling exercises prior to field investigations. In this approach, proposed field surveys are first numerically simulated given the expected electrical properties of the site, and the resulting hypothetical data are then analyzed using inverse models. Performing ERI forward/inverse modeling, however, requires substantial expertise and can take many hours to implement. We present a new spreadsheet-based tool, the Scenario Evaluator for Electrical Resistivity (SEER), which features a graphical user interface that allows users to manipulate a resistivity model and instantly view how that model would likely be interpreted by an ERI survey. The SEER tool is intended for use by those who wish to determine the value of including ERI to achieve project goals, and is designed to have broad utility in industry, teaching, and research.

  9. Using an Explicit Emission Tagging Method in Global Modeling of Source-Receptor Relationships for Black Carbon in the Arctic: Variations, Sources and Transport Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hailong; Rasch, Philip J.; Easter, Richard C.; Singh, Balwinder; Zhang, Rudong; Ma, Po-Lun; Qian, Yun; Ghan, Steven J.; Beagley, Nathaniel

    2014-11-27

    We introduce an explicit emission tagging technique in the Community Atmosphere Model to quantify source-region-resolved characteristics of black carbon (BC), focusing on the Arctic. Explicit tagging of BC source regions without perturbing the emissions makes it straightforward to establish source-receptor relationships and transport pathways, providing a physically consistent and computationally efficient approach to produce a detailed characterization of the destiny of regional BC emissions and the potential for mitigation actions. Our analysis shows that the contributions of major source regions to the global BC burden are not proportional to the respective emissions due to strong region-dependent removal rates and lifetimes, while the contributions to BC direct radiative forcing show a near-linear dependence on their respective contributions to the burden. Distant sources contribute to BC in remote regions mostly in the mid- and upper troposphere, having much less impact on lower-level concentrations (and deposition) than on burden. Arctic BC concentrations, deposition and source contributions all have strong seasonal variations. Eastern Asia contributes the most to the wintertime Arctic burden. Northern Europe emissions are more important to both surface concentration and deposition in winter than in summer. The largest contribution to Arctic BC in the summer is from Northern Asia. Although local emissions contribute less than 10% to the annual mean BC burden and deposition within the Arctic, the per-emission efficiency is much higher than for major non-Arctic sources. The interannual variability (1996-2005) due to meteorology is small in annual mean BC burden and radiative forcing but is significant in yearly seasonal means over the Arctic. When a slow aging treatment of BC is introduced, the increase of BC lifetime and burden is source-dependent. Global BC forcing-per-burden efficiency also increases primarily due to changes in BC vertical distributions. The

  10. DsixTools: the standard model effective field theory toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Celis, Alejandro [Ludwig-Maximilians-Universitaet Muenchen, Fakultaet fuer Physik, Arnold Sommerfeld Center for Theoretical Physics, Munich (Germany); Fuentes-Martin, Javier; Vicente, Avelino [Universitat de Valencia-CSIC, Instituto de Fisica Corpuscular, Valencia (Spain); Virto, Javier [University of Bern, Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, Bern (Switzerland)

    2017-06-15

    We present DsixTools, a Mathematica package for the handling of the dimension-six standard model effective field theory. Among other features, DsixTools allows the user to perform the full one-loop renormalization group evolution of the Wilson coefficients in the Warsaw basis. This is achieved thanks to the SMEFTrunner module, which implements the full one-loop anomalous dimension matrix previously derived in the literature. In addition, DsixTools also contains modules devoted to the matching to the ΔB = ΔS = 1, 2 and ΔB = ΔC = 1 operators of the Weak Effective Theory at the electroweak scale, and their QCD and QED Renormalization group evolution below the electroweak scale. (orig.)

  11. Assessing conditions influencing the longitudinal distribution of exotic brown trout (Salmo trutta) in a mountain stream: a spatially-explicit modeling approach

    Science.gov (United States)

    Meredith, Christy S.; Budy, Phaedra; Hooten, Mevin B.; Oliveira Prates, Marcos

    2017-01-01

    Trout species often segregate along elevational gradients, yet the mechanisms driving this pattern are not fully understood. On the Logan River, Utah, USA, exotic brown trout (Salmo trutta) dominate at low elevations but are near-absent from high elevations with native Bonneville cutthroat trout (Onchorhynchus clarkii utah). We used a spatially-explicit Bayesian modeling approach to evaluate how abiotic conditions (describing mechanisms related to temperature and physical habitat) as well as propagule pressure explained the distribution of brown trout in this system. Many covariates strongly explained redd abundance based on model performance and coefficient strength, including average annual temperature, average summer temperature, gravel availability, distance from a concentrated stocking area, and anchor ice-impeded distance from a concentrated stocking area. In contrast, covariates that exhibited low performance in models and/or a weak relationship to redd abundance included reach-average water depth, stocking intensity to the reach, average winter temperature, and number of days with anchor ice. Even if climate change creates more suitable summer temperature conditions for brown trout at high elevations, our findings suggest their success may be limited by other conditions. The potential role of anchor ice in limiting movement upstream is compelling considering evidence suggesting anchor ice prevalence on the Logan River has decreased significantly over the last several decades, likely in response to climatic changes. Further experimental and field research is needed to explore the role of anchor ice, spawning gravel availability, and locations of historical stocking in structuring brown trout distributions on the Logan River and elsewhere.

  12. Transparent Model Transformation: Turning Your Favourite Model Editor into a Transformation Tool

    DEFF Research Database (Denmark)

    Acretoaie, Vlad; Störrle, Harald; Strüber, Daniel

    2015-01-01

    Current model transformation languages are supported by dedicated editors, often closely coupled to a single execution engine. We introduce Transparent Model Transformation, a paradigm enabling modelers to specify transformations using a familiar tool: their model editor. We also present VMTL......, the first transformation language implementing the principles of Transparent Model Transformation: syntax, environment, and execution transparency. VMTL works by weaving a transformation aspect into its host modeling language. We show how our implementation of VMTL turns any model editor into a flexible...... model transformation tool sharing the model editor’s benefits, transparently....

  13. Models as Tools of Analysis of a Network Organisation

    Directory of Open Access Journals (Sweden)

    Wojciech Pająk

    2013-06-01

    Full Text Available The paper presents models which may be applied as tools of analysis of a network organisation. The starting point of the discussion is defining the following terms: supply chain and network organisation. Further parts of the paper present basic assumptions analysis of a network organisation. Then the study characterises the best known models utilised in analysis of a network organisation. The purpose of the article is to define the notion and the essence of network organizations and to present the models used for their analysis.

  14. ISAC: A tool for aeroservoelastic modeling and analysis

    Science.gov (United States)

    Adams, William M., Jr.; Hoadley, Sherwood Tiffany

    1993-01-01

    The capabilities of the Interaction of Structures, Aerodynamics, and Controls (ISAC) system of program modules is discussed. The major modeling, analysis, and data management components of ISAC are identified. Equations of motion are displayed for a Laplace-domain representation of the unsteady aerodynamic forces. Options for approximating a frequency-domain representation of unsteady aerodynamic forces with rational functions of the Laplace variable are shown. Linear time invariant state-space equations of motion that result are discussed. Model generation and analyses of stability and dynamic response characteristics are shown for an aeroelastic vehicle which illustrates some of the capabilities of ISAC as a modeling and analysis tool for aeroelastic applications.

  15. MODELING OF ANIMATED SIMULATIONS BY MAXIMA PROGRAM TOOLS

    Directory of Open Access Journals (Sweden)

    Nataliya O. Bugayets

    2015-06-01

    Full Text Available The article deals with the methodical features in training of computer simulation of systems and processes using animation. In the article the importance of visibility of educational material that combines sensory and thinking sides of cognition is noted. The concept of modeling and the process of building models has been revealed. Attention is paid to the development of skills that are essential for effective learning of animated simulation by visual aids. The graphical environment tools of the computer mathematics system Maxima for animated simulation are described. The examples of creation of models animated visual aids and their use for the development of research skills are presented.

  16. Model Fusion Tool - the Open Environmental Modelling Platform Concept

    Science.gov (United States)

    Kessler, H.; Giles, J. R.

    2010-12-01

    The vision of an Open Environmental Modelling Platform - seamlessly linking geoscience data, concepts and models to aid decision making in times of environmental change. Governments and their executive agencies across the world are facing increasing pressure to make decisions about the management of resources in light of population growth and environmental change. In the UK for example, groundwater is becoming a scarce resource for large parts of its most densely populated areas. At the same time river and groundwater flooding resulting from high rainfall events are increasing in scale and frequency and sea level rise is threatening the defences of coastal cities. There is also a need for affordable housing, improved transport infrastructure and waste disposal as well as sources of renewable energy and sustainable food production. These challenges can only be resolved if solutions are based on sound scientific evidence. Although we have knowledge and understanding of many individual processes in the natural sciences it is clear that a single science discipline is unable to answer the questions and their inter-relationships. Modern science increasingly employs computer models to simulate the natural, economic and human system. Management and planning requires scenario modelling, forecasts and ‘predictions’. Although the outputs are often impressive in terms of apparent accuracy and visualisation, they are inherently not suited to simulate the response to feedbacks from other models of the earth system, such as the impact of human actions. Geological Survey Organisations (GSO) are increasingly employing advances in Information Technology to visualise and improve their understanding of geological systems. Instead of 2 dimensional paper maps and reports many GSOs now produce 3 dimensional geological framework models and groundwater flow models as their standard output. Additionally the British Geological Survey have developed standard routines to link geological

  17. Using the IEA ETSAP modelling tools for Denmark

    Energy Technology Data Exchange (ETDEWEB)

    Grohnheit, Poul Erik

    2008-12-15

    An important part of the cooperation within the IEA (International Energy Agency) is organised through national contributions to 'Implementation Agreements' on energy technology and energy analyses. One of them is ETSAP (Energy Technology Systems Analysis Programme), started in 1976. Denmark has signed the agreement and contributed to some early annexes. This project is motivated by an invitation to participate in ETSAP Annex X, 'Global Energy Systems and Common Analyses: Climate friendly, Secure and Productive Energy Systems' for the period 2005 to 2007. The main activity is semi-annual workshops focusing on presentations of model analyses and use of the ETSAP tools (the MARKAL/TIMES family of models). The project was also planned to benefit from the EU project 'NEEDS - New Energy Externalities Developments for Sustainability'. ETSAP is contributing to a part of NEEDS that develops the TIMES model for 29 European countries with assessment of future technologies. An additional project 'Monitoring and Evaluation of the RES directives: implementation in EU27 and policy recommendations for 2020' (RES2020) under Intelligent Energy Europe was added, as well as the Danish 'Centre for Energy, Environment and Health (CEEH), starting from January 2007. This report summarises the activities under ETSAP Annex X and related project, emphasising the development of modelling tools that will be useful for modelling the Danish energy system. It is also a status report for the development of a model for Denmark, focusing on the tools and features that allow comparison with other countries and, particularly, to evaluate assumptions and results in international models covering Denmark. (au)

  18. CryoModel: a cryostat thermal performance simulation tool

    CERN Document Server

    Pérez Caparrós, D

    2011-01-01

    In the design process of cryostats for accelerators equipment (magnets or RF cavities), it is of interest to estimate downtime for intervention. For this purpose, it is necessary to understand the temperature transients of the accelerator components during warm-up and cool-down processes. In this report, a mathematical model and a simulation tool to study the main heat transfer phenomena of a generic horizontal cryostat (radiation, with or without multilayer insulation system, actively cooled thermal shielding, thermal conduction through supporting systems, etc.) is presented. The thermal model and simulator have been benchmarked on experimental data from transients of the Large Hadron Collider (LHC). The presented tool is now being used to estimate the warm-up time needed for machine intervention in case of replacement of one cryomodule of the Superconducting Proton Linear accelerator (SPL).

  19. Using the Soil and Water Assessment Tool (SWAT) to model ecosystem services: A systematic review

    Science.gov (United States)

    Francesconi, Wendy; Srinivasan, Raghavan; Pérez-Miñana, Elena; Willcock, Simon P.; Quintero, Marcela

    2016-04-01

    SWAT, a watershed modeling tool has been proposed to help quantify ecosystem services. The concept of ecosystem services incorporates the collective benefits natural systems provide primarily to human beings. It is becoming increasingly important to track the impact that human activities have on the environment in order to determine its resilience and sustainability. The objectives of this paper are to provide an overview of efforts using SWAT to quantify ecosystem services, to determine the model's capability examining various types of services, and to describe the approach used by various researchers. A literature review was conducted to identify studies in which SWAT was explicitly used for quantifying ecosystem services in terms of provisioning, regulating, supporting, and cultural aspects. A total of 44 peer reviewed publications were identified. Most of these used SWAT to quantify provisioning services (34%), regulating services (27%), or a combination of both (25%). While studies using SWAT for evaluating ecosystem services are limited (approximately 1% of SWAT's peered review publications), and usage (vs. potential) of services by beneficiaries is a current model limitation, the available literature sets the stage for the continuous development and potential of SWAT as a methodological framework for quantifying ecosystem services to assist in decision-making.

  20. Surviving the present: Modeling tools for organizational change

    Energy Technology Data Exchange (ETDEWEB)

    Pangaro, P. (Pangaro Inc., Washington, DC (United States))

    1992-01-01

    The nuclear industry, like the rest of modern American business, is beset by a confluence of economic, technological, competitive, regulatory, and political pressures. For better or worse, business schools and management consultants have leapt to the rescue, offering the most modern conveniences that they can purvey. Recent advances in the study of organizations have led to new tools for their analysis, revision, and repair. There are two complementary tools that do not impose values or injunctions in themselves. One, called the organization modeler, captures the hierarchy of purposes that organizations and their subparts carry out. Any deficiency or pathology is quickly illuminated, and requirements for repair are made clear. The second, called THOUGHTSTICKER, is used to capture the semantic content of the conversations that occur across the interactions of parts of an organization. The distinctions and vocabulary in the language of an organization, and the relations within that domain, are elicited from the participants so that all three are available for debate and refinement. The product of the applications of these modeling tools is not the resulting models but rather the enhancement of the organization as a consequence of the process of constructing them.

  1. Modelling stillbirth mortality reduction with the Lives Saved Tool.

    Science.gov (United States)

    Blencowe, Hannah; Chou, Victoria B; Lawn, Joy E; Bhutta, Zulfiqar A

    2017-11-07

    The worldwide burden of stillbirths is large, with an estimated 2.6 million babies stillborn in 2015 including 1.3 million dying during labour. The Every Newborn Action Plan set a stillbirth target of ≤12 per 1000 in all countries by 2030. Planning tools will be essential as countries set policy and plan investment to scale up interventions to meet this target. This paper summarises the approach taken for modelling the impact of scaling-up health interventions on stillbirths in the Lives Saved tool (LiST), and potential future refinements. The specific application to stillbirths of the general method for modelling the impact of interventions in LiST is described. The evidence for the effectiveness of potential interventions to reduce stillbirths are reviewed and the assumptions of the affected fraction of stillbirths who could potentially benefit from these interventions are presented. The current assumptions and their effects on stillbirth reduction are described and potential future improvements discussed. High quality evidence are not available for all parameters in the LiST stillbirth model. Cause-specific mortality data is not available for stillbirths, therefore stillbirths are modelled in LiST using an attributable fraction approach by timing of stillbirths (antepartum/ intrapartum). Of 35 potential interventions to reduce stillbirths identified, eight interventions are currently modelled in LiST. These include childbirth care, induction for prolonged pregnancy, multiple micronutrient and balanced energy supplementation, malaria prevention and detection and management of hypertensive disorders of pregnancy, diabetes and syphilis. For three of the interventions, childbirth care, detection and management of hypertensive disorders of pregnancy, and diabetes the estimate of effectiveness is based on expert opinion through a Delphi process. Only for malaria is coverage information available, with coverage estimated using expert opinion for all other

  2. An ensemble model of QSAR tools for regulatory risk assessment.

    Science.gov (United States)

    Pradeep, Prachi; Povinelli, Richard J; White, Shannon; Merrill, Stephen J

    2016-01-01

    Quantitative structure activity relationships (QSARs) are theoretical models that relate a quantitative measure of chemical structure to a physical property or a biological effect. QSAR predictions can be used for chemical risk assessment for protection of human and environmental health, which makes them interesting to regulators, especially in the absence of experimental data. For compatibility with regulatory use, QSAR models should be transparent, reproducible and optimized to minimize the number of false negatives. In silico QSAR tools are gaining wide acceptance as a faster alternative to otherwise time-consuming clinical and animal testing methods. However, different QSAR tools often make conflicting predictions for a given chemical and may also vary in their predictive performance across different chemical datasets. In a regulatory context, conflicting predictions raise interpretation, validation and adequacy concerns. To address these concerns, ensemble learning techniques in the machine learning paradigm can be used to integrate predictions from multiple tools. By leveraging various underlying QSAR algorithms and training datasets, the resulting consensus prediction should yield better overall predictive ability. We present a novel ensemble QSAR model using Bayesian classification. The model allows for varying a cut-off parameter that allows for a selection in the desirable trade-off between model sensitivity and specificity. The predictive performance of the ensemble model is compared with four in silico tools (Toxtree, Lazar, OECD Toolbox, and Danish QSAR) to predict carcinogenicity for a dataset of air toxins (332 chemicals) and a subset of the gold carcinogenic potency database (480 chemicals). Leave-one-out cross validation results show that the ensemble model achieves the best trade-off between sensitivity and specificity (accuracy: 83.8 % and 80.4 %, and balanced accuracy: 80.6 % and 80.8 %) and highest inter-rater agreement [kappa (κ): 0

  3. Information Theoretic Tools for Parameter Fitting in Coarse Grained Models

    KAUST Repository

    Kalligiannaki, Evangelia

    2015-01-07

    We study the application of information theoretic tools for model reduction in the case of systems driven by stochastic dynamics out of equilibrium. The model/dimension reduction is considered by proposing parametrized coarse grained dynamics and finding the optimal parameter set for which the relative entropy rate with respect to the atomistic dynamics is minimized. The minimization problem leads to a generalization of the force matching methods to non equilibrium systems. A multiplicative noise example reveals the importance of the diffusion coefficient in the optimization problem.

  4. A Tool for Sharing Empirical Models of Climate Impacts

    Science.gov (United States)

    Rising, J.; Kopp, R. E.; Hsiang, S. M.

    2013-12-01

    Scientists, policy advisors, and the public struggle to synthesize the quickly evolving empirical work on climate change impacts. The Integrated Assessment Models (IAMs) used to estimate the impacts of climate change and the effects of adaptation and mitigation policies can also benefit greatly from recent empirical results (Kopp, Hsiang & Oppenheimer, Impacts World 2013 discussion paper). This paper details a new online tool for exploring, analyzing, combining, and communicating a wide range of impact results, and supporting their integration into IAMs. The tool uses a new database of statistical results, which researchers can expand both in depth (by providing additional results that describing existing relationships) and breadth (by adding new relationships). Scientists can use the tool to quickly perform meta-analyses of related results, using Bayesian techniques to produce pooled and partially-pooled posterior distributions. Policy advisors can apply the statistical results to particular contexts, and combine different kinds of results in a cost-benefit framework. For example, models of the impact of temperature changes on agricultural yields can be first aggregated to build a best-estimate of the effect under given assumptions, then compared across countries using different temperature scenarios, and finally combined to estimate a social cost of carbon. The general public can better understand the many estimates of climate impacts and their range of uncertainty by exploring these results dynamically, with maps, bar charts, and dose-response-style plots. Front page of the climate impacts tool website. Sample "collections" of models, within which all results are estimates of the same fundamental relationship, are shown on the right. Simple pooled result for Gelman's "8 schools" example. Pooled results are calculated analytically, while partial-pooling (Bayesian hierarchical estimation) uses posterior simulations.

  5. Investigation of inflammation and tissue patterning in the gut using a Spatially Explicit General-purpose Model of Enteric Tissue (SEGMEnT.

    Directory of Open Access Journals (Sweden)

    Chase Cockrell

    2014-03-01

    Full Text Available The mucosa of the intestinal tract represents a finely tuned system where tissue structure strongly influences, and is turn influenced by, its function as both an absorptive surface and a defensive barrier. Mucosal architecture and histology plays a key role in the diagnosis, characterization and pathophysiology of a host of gastrointestinal diseases. Inflammation is a significant factor in the pathogenesis in many gastrointestinal diseases, and is perhaps the most clinically significant control factor governing the maintenance of the mucosal architecture by morphogenic pathways. We propose that appropriate characterization of the role of inflammation as a controller of enteric mucosal tissue patterning requires understanding the underlying cellular and molecular dynamics that determine the epithelial crypt-villus architecture across a range of conditions from health to disease. Towards this end we have developed the Spatially Explicit General-purpose Model of Enteric Tissue (SEGMEnT to dynamically represent existing knowledge of the behavior of enteric epithelial tissue as influenced by inflammation with the ability to generate a variety of pathophysiological processes within a common platform and from a common knowledge base. In addition to reproducing healthy ileal mucosal dynamics as well as a series of morphogen knock-out/inhibition experiments, SEGMEnT provides insight into a range of clinically relevant cellular-molecular mechanisms, such as a putative role for Phosphotase and tensin homolog/phosphoinositide 3-kinase (PTEN/PI3K as a key point of crosstalk between inflammation and morphogenesis, the protective role of enterocyte sloughing in enteric ischemia-reperfusion and chronic low level inflammation as a driver for colonic metaplasia. These results suggest that SEGMEnT can serve as an integrating platform for the study of inflammation in gastrointestinal disease.

  6. Advances in Intelligent Modelling and Simulation Simulation Tools and Applications

    CERN Document Server

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

    2012-01-01

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

  7. Computational Modeling, Formal Analysis, and Tools for Systems Biology.

    Directory of Open Access Journals (Sweden)

    Ezio Bartocci

    2016-01-01

    Full Text Available As the amount of biological data in the public domain grows, so does the range of modeling and analysis techniques employed in systems biology. In recent years, a number of theoretical computer science developments have enabled modeling methodology to keep pace. The growing interest in systems biology in executable models and their analysis has necessitated the borrowing of terms and methods from computer science, such as formal analysis, model checking, static analysis, and runtime verification. Here, we discuss the most important and exciting computational methods and tools currently available to systems biologists. We believe that a deeper understanding of the concepts and theory highlighted in this review will produce better software practice, improved investigation of complex biological processes, and even new ideas and better feedback into computer science.

  8. Dynamic wind turbine models in power system simulation tool

    DEFF Research Database (Denmark)

    Hansen, Anca D.; Iov, Florin; Sørensen, Poul

    This report presents a collection of models and control strategies developed and implemented in the power system simulation tool PowerFactory DIgSILENT for different wind turbine concepts. It is the second edition of Risø-R-1400(EN) and it gathers and describes a whole wind turbine model database...... built-op and developed during several national research projects, carried out at Risø DTU National Laboratory for Sustainable Energy and Aalborg University, in the period 2001-2007. The overall objective of these projects was to create a wind turbine model database able to support the analysis...... of the interaction between the mechanical structure of the wind turbine and the electrical grid during different operational modes. The report provides thus a description of the wind turbines modelling, both at a component level and at a system level. The report contains both the description of DIgSILENT built...

  9. Requirements for UML and OWL Integration Tool for User Data Consistency Modeling and Testing

    DEFF Research Database (Denmark)

    Nytun, J. P.; Jensen, Christian Søndergaard; Oleshchuk, V. A.

    2003-01-01

    . In this paper we analyze requirements for a tool that support integration of UML models and ontologies written in languages like the W3C Web Ontology Language (OWL). The tool can be used in the following way: after loading two legacy models into the tool, the tool user connects them by inserting modeling...

  10. MGP : a tool for wide range temperature modelling

    Energy Technology Data Exchange (ETDEWEB)

    Morales, A.F. [Inst. Tecnologico Autonomo de Mexico, Mexico City (Mexico); Seisdedos, L.V. [Univ. de Oriente, Santiago de Cuba (Cuba). Dept. de Control Automatico

    2006-07-01

    This paper proposed a practical temperature modelling tool that used genetic multivariate polynomials to determine polynomial expressions of enthalpy and empirical heat transfer equations in superheaters. The model was designed to transform static parameter estimations from distributed into lumped parameter systems. Two dynamic regimes were explored: (1) a power dynamics regime containing major inputs and outputs needed for overall plant control; and (2) a steam temperature dynamics scheme that considered consecutive superheater sections considered in terms of cooling water mass flow and steam mass flow. The single lumped parameters model was developed to provide temperature control for a fossil fuel-fired power plant. The design procedure used enthalpy to determine the plant's energy balance. The enthalpy curve was seen as a function of either temperature and steam pressure. A graphic simulation tool was used to optimize the model by comparing real and simulated plant data. The study showed that the amount of energy taken by the steam mass flow per time unit can be calculated by measuring temperatures and pressures at both ends of the superheater. An algorithm was then developed to determine the polynomial's coefficients according to best curve fitting over the training set and best maximum errors. It was concluded that a unified approach is now being developed to simulate and emulate the dynamics of steam temperature for each section's attemporator-superheater. 14 refs., 3 tabs., 5 figs.

  11. CDPOP: A spatially explicit cost distance population genetics program

    Science.gov (United States)

    Erin L. Landguth; S. A. Cushman

    2010-01-01

    Spatially explicit simulation of gene flow in complex landscapes is essential to explain observed population responses and provide a foundation for landscape genetics. To address this need, we wrote a spatially explicit, individual-based population genetics model (CDPOP). The model implements individual-based population modelling with Mendelian inheritance and k-allele...

  12. Landscape capability models as a tool to predict fine-scale forest bird occupancy and abundance

    Science.gov (United States)

    Loman, Zachary G.; DeLuca, William; Harrison, Daniel J.; Loftin, Cynthia S.; Rolek, Brian W.; Wood, Petra

    2018-01-01

    ContextSpecies-specific models of landscape capability (LC) can inform landscape conservation design. Landscape capability is “the ability of the landscape to provide the environment […] and the local resources […] needed for survival and reproduction […] in sufficient quantity, quality and accessibility to meet the life history requirements of individuals and local populations.” Landscape capability incorporates species’ life histories, ecologies, and distributions to model habitat for current and future landscapes and climates as a proactive strategy for conservation planning.ObjectivesWe tested the ability of a set of LC models to explain variation in point occupancy and abundance for seven bird species representative of spruce-fir, mixed conifer-hardwood, and riparian and wooded wetland macrohabitats.MethodsWe compiled point count data sets used for biological inventory, species monitoring, and field studies across the northeastern United States to create an independent validation data set. Our validation explicitly accounted for underestimation in validation data using joint distance and time removal sampling.ResultsBlackpoll warbler (Setophaga striata), wood thrush (Hylocichla mustelina), and Louisiana (Parkesia motacilla) and northern waterthrush (P. noveboracensis) models were validated as predicting variation in abundance, although this varied from not biologically meaningful (1%) to strongly meaningful (59%). We verified all seven species models [including ovenbird (Seiurus aurocapilla), blackburnian (Setophaga fusca) and cerulean warbler (Setophaga cerulea)], as all were positively related to occupancy data.ConclusionsLC models represent a useful tool for conservation planning owing to their predictive ability over a regional extent. As improved remote-sensed data become available, LC layers are updated, which will improve predictions.

  13. The Role of Explicit and Implicit Self-Esteem in Peer Modeling of Palatable Food Intake: A Study on Social Media Interaction among Youngsters

    NARCIS (Netherlands)

    Bevelander, K.E.; Anschutz, D.J.; Creemers, D.H.M.; Kleinjan, M.; Engels, R.C.M.E.

    2013-01-01

    Objective: This experimental study investigated the impact of peers on palatable food intake of youngsters within a social media setting. To determine whether this effect was moderated by self-esteem, the present study examined the roles of global explicit self-esteem (ESE), body esteem (BE) and

  14. Analysis of Sequence Diagram Layout in Advanced UML Modelling Tools

    Directory of Open Access Journals (Sweden)

    Ņikiforova Oksana

    2016-05-01

    Full Text Available System modelling using Unified Modelling Language (UML is the task that should be solved for software development. The more complex software becomes the higher requirements are stated to demonstrate the system to be developed, especially in its dynamic aspect, which in UML is offered by a sequence diagram. To solve this task, the main attention is devoted to the graphical presentation of the system, where diagram layout plays the central role in information perception. The UML sequence diagram due to its specific structure is selected for a deeper analysis on the elements’ layout. The authors research represents the abilities of modern UML modelling tools to offer automatic layout of the UML sequence diagram and analyse them according to criteria required for the diagram perception.

  15. Combining modelling tools to evaluate a goose management scheme.

    Science.gov (United States)

    Baveco, Johannes M; Bergjord, Anne-Kari; Bjerke, Jarle W; Chudzińska, Magda E; Pellissier, Loïc; Simonsen, Caroline E; Madsen, Jesper; Tombre, Ingunn M; Nolet, Bart A

    2017-03-01

    Many goose species feed on agricultural land, and with growing goose numbers, conflicts with agriculture are increasing. One possible solution is to designate refuge areas where farmers are paid to leave geese undisturbed. Here, we present a generic modelling tool that can be used to designate the best locations for refuges and to gauge the area needed to accommodate the geese. With a species distribution model, locations are ranked according to goose suitability. The size of the area to be designated as refuge can be chosen by including more or less suitable locations. A resource depletion model is then used to estimate whether enough resources are available within the designated refuge to accommodate all geese, taking into account the dynamics of food resources, including depletion by geese. We illustrate this with the management scheme for pink-footed goose Anser brachyrhynchus implemented in Norway. Here, all geese can be accommodated, but damage levels appear to depend on weather, land use and refuge size.

  16. Desktop Modeling Tools for Lidar Remote Sensing and Spectral Optimizations

    Science.gov (United States)

    Pliutau, D.; Prasad, N. S.

    2013-12-01

    We developed a set of cross-platform desktop modeling tools for molecular spectroscopy and atmospheric remote sensing optimization calculations which rely on the HITRAN database in spectral calculations. As part of the simulation framework its components further use the line-by-line radiative transfer model (LBLRTM) for radiative transfer simulations and a number of NASA Earth datasets including the Modern Era Retrospective Analysis for Research and Applications (MERRA) in computational routines. Currently the framework includes a spectral optimization program used to identify potential measurement wavelengths exhibiting minimum temperature, pressure and water vapor interferences, and a shell component for easier operation of the LBLRTM. An additional lidar simulation module for weighting functions selection and further lidar optimizations is also being incorporated into the modeling framework. The developed simulation components are applicable to the analysis of various atmospheric species and have been used in performance prediction calculations for the sensing of atmospheric CO2 in the future ASCENDS mission.

  17. Mathematical modeling of physiological systems: an essential tool for discovery.

    Science.gov (United States)

    Glynn, Patric; Unudurthi, Sathya D; Hund, Thomas J

    2014-08-28

    Mathematical models are invaluable tools for understanding the relationships between components of a complex system. In the biological context, mathematical models help us understand the complex web of interrelations between various components (DNA, proteins, enzymes, signaling molecules etc.) in a biological system, gain better understanding of the system as a whole, and in turn predict its behavior in an altered state (e.g. disease). Mathematical modeling has enhanced our understanding of multiple complex biological processes like enzyme kinetics, metabolic networks, signal transduction pathways, gene regulatory networks, and electrophysiology. With recent advances in high throughput data generation methods, computational techniques and mathematical modeling have become even more central to the study of biological systems. In this review, we provide a brief history and highlight some of the important applications of modeling in biological systems with an emphasis on the study of excitable cells. We conclude with a discussion about opportunities and challenges for mathematical modeling going forward. In a larger sense, the review is designed to help answer a simple but important question that theoreticians frequently face from interested but skeptical colleagues on the experimental side: "What is the value of a model?" Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Using Sophisticated Tools and Models in Science Teaching

    Science.gov (United States)

    Tinker, Robert

    2004-03-01

    As physicists, we learn a great deal by interacting with computational models and tools. It seems natural that providing these experiences to young students could lead to major advances in science teaching and learning. There are, however, many problems in realizing this vision. Research-based tools often have poor user interfaces, provide limited or delayed visual representations, are too complex, and, in general, incorporate many implicit assumptions about the user that are not true for beginners. Even applications that are accessible to beginners can have too many options and need to provide flexible guidance or scaffolding that helps the learner use the computational resources effectively. Three related architectures will be described that provide flexible pedagogical guidance for large applications. These architectures separate the technical problem of generating a suitable application from the pedagogical problem of helping students learn from interacting with the application. They also support detailed student assessment, and are, therefore, helpful to teachers and researchers. Examples will be drawn from a large molecular dynamics application as well as models of dynamics and genetics. This work is part of a large longitudinal study of model use across the high school curriculum and a new Center of Technology-Enhanced Science Learning that will be described.

  19. Performance Analysis, Modeling and Scaling of HPC Applications and Tools

    Energy Technology Data Exchange (ETDEWEB)

    Bhatele, Abhinav [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-01-13

    E cient use of supercomputers at DOE centers is vital for maximizing system throughput, mini- mizing energy costs and enabling science breakthroughs faster. This requires complementary e orts along several directions to optimize the performance of scienti c simulation codes and the under- lying runtimes and software stacks. This in turn requires providing scalable performance analysis tools and modeling techniques that can provide feedback to physicists and computer scientists developing the simulation codes and runtimes respectively. The PAMS project is using time allocations on supercomputers at ALCF, NERSC and OLCF to further the goals described above by performing research along the following fronts: 1. Scaling Study of HPC applications; 2. Evaluation of Programming Models; 3. Hardening of Performance Tools; 4. Performance Modeling of Irregular Codes; and 5. Statistical Analysis of Historical Performance Data. We are a team of computer and computational scientists funded by both DOE/NNSA and DOE/ ASCR programs such as ECRP, XStack (Traleika Glacier, PIPER), ExaOSR (ARGO), SDMAV II (MONA) and PSAAP II (XPACC). This allocation will enable us to study big data issues when analyzing performance on leadership computing class systems and to assist the HPC community in making the most e ective use of these resources.

  20. Evaluation of reliability modeling tools for advanced fault tolerant systems

    Science.gov (United States)

    Baker, Robert; Scheper, Charlotte

    1986-01-01

    The Computer Aided Reliability Estimation (CARE III) and Automated Reliability Interactice Estimation System (ARIES 82) reliability tools for application to advanced fault tolerance aerospace systems were evaluated. To determine reliability modeling requirements, the evaluation focused on the Draper Laboratories' Advanced Information Processing System (AIPS) architecture as an example architecture for fault tolerance aerospace systems. Advantages and limitations were identified for each reliability evaluation tool. The CARE III program was designed primarily for analyzing ultrareliable flight control systems. The ARIES 82 program's primary use was to support university research and teaching. Both CARE III and ARIES 82 were not suited for determining the reliability of complex nodal networks of the type used to interconnect processing sites in the AIPS architecture. It was concluded that ARIES was not suitable for modeling advanced fault tolerant systems. It was further concluded that subject to some limitations (the difficulty in modeling systems with unpowered spare modules, systems where equipment maintenance must be considered, systems where failure depends on the sequence in which faults occurred, and systems where multiple faults greater than a double near coincident faults must be considered), CARE III is best suited for evaluating the reliability of advanced tolerant systems for air transport.

  1. Integrated modeling tool for performance engineering of complex computer systems

    Science.gov (United States)

    Wright, Gary; Ball, Duane; Hoyt, Susan; Steele, Oscar

    1989-01-01

    This report summarizes Advanced System Technologies' accomplishments on the Phase 2 SBIR contract NAS7-995. The technical objectives of the report are: (1) to develop an evaluation version of a graphical, integrated modeling language according to the specification resulting from the Phase 2 research; and (2) to determine the degree to which the language meets its objectives by evaluating ease of use, utility of two sets of performance predictions, and the power of the language constructs. The technical approach followed to meet these objectives was to design, develop, and test an evaluation prototype of a graphical, performance prediction tool. The utility of the prototype was then evaluated by applying it to a variety of test cases found in the literature and in AST case histories. Numerous models were constructed and successfully tested. The major conclusion of this Phase 2 SBIR research and development effort is that complex, real-time computer systems can be specified in a non-procedural manner using combinations of icons, windows, menus, and dialogs. Such a specification technique provides an interface that system designers and architects find natural and easy to use. In addition, PEDESTAL's multiview approach provides system engineers with the capability to perform the trade-offs necessary to produce a design that meets timing performance requirements. Sample system designs analyzed during the development effort showed that models could be constructed in a fraction of the time required by non-visual system design capture tools.

  2. Conceptual Models as Tools for Communication Across Disciplines

    Directory of Open Access Journals (Sweden)

    Marieke Heemskerk

    2003-12-01

    Full Text Available To better understand and manage complex social-ecological systems, social scientists and ecologists must collaborate. However, issues related to language and research approaches can make it hard for researchers in different fields to work together. This paper suggests that researchers can improve interdisciplinary science through the use of conceptual models as a communication tool. The authors share lessons from a workshop in which interdisciplinary teams of young scientists developed conceptual models of social-ecological systems using data sets and metadata from Long-Term Ecological Research sites across the United States. Both the process of model building and the models that were created are discussed. The exercise revealed that the presence of social scientists in a group influenced the place and role of people in the models. This finding suggests that the participation of both ecologists and social scientists in the early stages of project development may produce better questions and more accurate models of interactions between humans and ecosystems. Although the participants agreed that a better understanding of human intentions and behavior would advance ecosystem science, they felt that interdisciplinary research might gain more by training strong disciplinarians than by merging ecology and social sciences into a new field. It is concluded that conceptual models can provide an inspiring point of departure and a guiding principle for interdisciplinary group discussions. Jointly developing a model not only helped the participants to formulate questions, clarify system boundaries, and identify gaps in existing data, but also revealed the thoughts and assumptions of fellow scientists. Although the use of conceptual models will not serve all purposes, the process of model building can help scientists, policy makers, and resource managers discuss applied problems and theory among themselves and with those in other areas.

  3. ExEP yield modeling tool and validation test results

    Science.gov (United States)

    Morgan, Rhonda; Turmon, Michael; Delacroix, Christian; Savransky, Dmitry; Garrett, Daniel; Lowrance, Patrick; Liu, Xiang Cate; Nunez, Paul

    2017-09-01

    EXOSIMS is an open-source simulation tool for parametric modeling of the detection yield and characterization of exoplanets. EXOSIMS has been adopted by the Exoplanet Exploration Programs Standards Definition and Evaluation Team (ExSDET) as a common mechanism for comparison of exoplanet mission concept studies. To ensure trustworthiness of the tool, we developed a validation test plan that leverages the Python-language unit-test framework, utilizes integration tests for selected module interactions, and performs end-to-end crossvalidation with other yield tools. This paper presents the test methods and results, with the physics-based tests such as photometry and integration time calculation treated in detail and the functional tests treated summarily. The test case utilized a 4m unobscured telescope with an idealized coronagraph and an exoplanet population from the IPAC radial velocity (RV) exoplanet catalog. The known RV planets were set at quadrature to allow deterministic validation of the calculation of physical parameters, such as working angle, photon counts and integration time. The observing keepout region was tested by generating plots and movies of the targets and the keepout zone over a year. Although the keepout integration test required the interpretation of a user, the test revealed problems in the L2 halo orbit and the parameterization of keepout applied to some solar system bodies, which the development team was able to address. The validation testing of EXOSIMS was performed iteratively with the developers of EXOSIMS and resulted in a more robust, stable, and trustworthy tool that the exoplanet community can use to simulate exoplanet direct-detection missions from probe class, to WFIRST, up to large mission concepts such as HabEx and LUVOIR.

  4. Explicit Instruction Elements in Core Reading Programs

    Science.gov (United States)

    Child, Angela R.

    2012-01-01

    Classroom teachers are provided instructional recommendations for teaching reading from their adopted core reading programs (CRPs). Explicit instruction elements or what is also called instructional moves, including direct explanation, modeling, guided practice, independent practice, discussion, feedback, and monitoring, were examined within CRP…

  5. Refinement of protein structures in explicit solvent

    NARCIS (Netherlands)

    Linge, J.P.; Williams, M.A.; Spronk, C.A.E.M.; Bonvin, A.M.J.J.|info:eu-repo/dai/nl/113691238; Nilges, M.

    2003-01-01

    We present a CPU efficient protocol for refinement of protein structures in a thin layer of explicit solvent and energy parameters with completely revised dihedral angle terms. Our approach is suitable for protein structures determined by theoretical (e.g., homology modeling or threading) or

  6. Explicit Finite Element Modeling of Multilayer Composite Fabric for Gas Turbine Engine Containment Systems, Phase II. Part 3; Material Model Development and Simulation of Experiments

    Science.gov (United States)

    Simmons, J.; Erlich, D.; Shockey, D.

    2009-01-01

    A team consisting of Arizona State University, Honeywell Engines, Systems & Services, the National Aeronautics and Space Administration Glenn Research Center, and SRI International collaborated to develop computational models and verification testing for designing and evaluating turbine engine fan blade fabric containment structures. This research was conducted under the Federal Aviation Administration Airworthiness Assurance Center of Excellence and was sponsored by the Aircraft Catastrophic Failure Prevention Program. The research was directed toward improving the modeling of a turbine engine fabric containment structure for an engine blade-out containment demonstration test required for certification of aircraft engines. The research conducted in Phase II began a new level of capability to design and develop fan blade containment systems for turbine engines. Significant progress was made in three areas: (1) further development of the ballistic fabric model to increase confidence and robustness in the material models for the Kevlar(TradeName) and Zylon(TradeName) material models developed in Phase I, (2) the capability was improved for finite element modeling of multiple layers of fabric using multiple layers of shell elements, and (3) large-scale simulations were performed. This report concentrates on the material model development and simulations of the impact tests.

  7. An Executable Architecture Tool for the Modeling and Simulation of Operational Process Models

    Science.gov (United States)

    2015-03-16

    potential for advanced analysis. Thus, the proposed tool uses ubiquitous software: MATLAB [11] and MS Visio , which do not require specialised training. A...between the simulation model and MS Visio , which in turn facilitates coalition coordination and combined iterative development. The proposed capability...several examples of process models developed in MS Visio which can be used with the proposed tool. A. DNDAF Products The Department of National Defense

  8. Introducing Modeling Transition Diagrams as a Tool to Connect Mathematical Modeling to Mathematical Thinking

    Science.gov (United States)

    Czocher, Jennifer A.

    2016-01-01

    This study contributes a methodological tool to reconstruct the cognitive processes and mathematical activities carried out by mathematical modelers. Represented as Modeling Transition Diagrams (MTDs), individual modeling routes were constructed for four engineering undergraduate students. Findings stress the importance and limitations of using…

  9. Assessment of fine-scale resource selection and spatially explicit habitat suitability modelling for a re-introduced tiger (Panthera tigris) population in central India.

    Science.gov (United States)

    Sarkar, Mriganka Shekhar; Krishnamurthy, Ramesh; Johnson, Jeyaraj A; Sen, Subharanjan; Saha, Goutam Kumar

    2017-01-01

    Large carnivores influence ecosystem functions at various scales. Thus, their local extinction is not only a species-specific conservation concern, but also reflects on the overall habitat quality and ecosystem value. Species-habitat relationships at fine scale reflect the individuals' ability to procure resources and negotiate intraspecific competition. Such fine scale habitat choices are more pronounced in large carnivores such as tiger ( Panthera tigris ), which exhibits competitive exclusion in habitat and mate selection strategies. Although landscape level policies and conservation strategies are increasingly promoted for tiger conservation, specific management interventions require knowledge of the habitat correlates at fine scale. We studied nine radio-collared individuals of a successfully reintroduced tiger population in Panna Tiger Reserve, central India, focussing on the species-habitat relationship at fine scales. With 16 eco-geographical variables, we performed Manly's selection ratio and K-select analyses to define population-level and individual-level variation in resource selection, respectively. We analysed the data obtained during the exploratory period of six tigers and during the settled period of eight tigers separately, and compared the consequent results. We further used the settled period characteristics to model and map habitat suitability based on the Mahalanobis D 2 method and the Boyce index. There was a clear difference in habitat selection by tigers between the exploratory and the settled period. During the exploratory period, tigers selected dense canopy and bamboo forests, but also spent time near villages and relocated village sites. However, settled tigers predominantly selected bamboo forests in complex terrain, riverine forests and teak-mixed forest, and totally avoided human settlements and agriculture areas. There were individual variations in habitat selection between exploratory and settled periods. Based on threshold limits

  10. Assessment of fine-scale resource selection and spatially explicit habitat suitability modelling for a re-introduced tiger (Panthera tigris population in central India

    Directory of Open Access Journals (Sweden)

    Mriganka Shekhar Sarkar

    2017-11-01

    Full Text Available Background Large carnivores influence ecosystem functions at various scales. Thus, their local extinction is not only a species-specific conservation concern, but also reflects on the overall habitat quality and ecosystem value. Species-habitat relationships at fine scale reflect the individuals’ ability to procure resources and negotiate intraspecific competition. Such fine scale habitat choices are more pronounced in large carnivores such as tiger (Panthera tigris, which exhibits competitive exclusion in habitat and mate selection strategies. Although landscape level policies and conservation strategies are increasingly promoted for tiger conservation, specific management interventions require knowledge of the habitat correlates at fine scale. Methods We studied nine radio-collared individuals of a successfully reintroduced tiger population in Panna Tiger Reserve, central India, focussing on the species-habitat relationship at fine scales. With 16 eco-geographical variables, we performed Manly’s selection ratio and K-select analyses to define population-level and individual-level variation in resource selection, respectively. We analysed the data obtained during the exploratory period of six tigers and during the settled period of eight tigers separately, and compared the consequent results. We further used the settled period characteristics to model and map habitat suitability based on the Mahalanobis D2 method and the Boyce index. Results There was a clear difference in habitat selection by tigers between the exploratory and the settled period. During the exploratory period, tigers selected dense canopy and bamboo forests, but also spent time near villages and relocated village sites. However, settled tigers predominantly selected bamboo forests in complex terrain, riverine forests and teak-mixed forest, and totally avoided human settlements and agriculture areas. There were individual variations in habitat selection between exploratory

  11. Assessment of fine-scale resource selection and spatially explicit habitat suitability modelling for a re-introduced tiger (Panthera tigris) population in central India

    Science.gov (United States)

    Sarkar, Mriganka Shekhar; Johnson, Jeyaraj A.; Sen, Subharanjan

    2017-01-01

    Background Large carnivores influence ecosystem functions at various scales. Thus, their local extinction is not only a species-specific conservation concern, but also reflects on the overall habitat quality and ecosystem value. Species-habitat relationships at fine scale reflect the individuals’ ability to procure resources and negotiate intraspecific competition. Such fine scale habitat choices are more pronounced in large carnivores such as tiger (Panthera tigris), which exhibits competitive exclusion in habitat and mate selection strategies. Although landscape level policies and conservation strategies are increasingly promoted for tiger conservation, specific management interventions require knowledge of the habitat correlates at fine scale. Methods We studied nine radio-collared individuals of a successfully reintroduced tiger population in Panna Tiger Reserve, central India, focussing on the species-habitat relationship at fine scales. With 16 eco-geographical variables, we performed Manly’s selection ratio and K-select analyses to define population-level and individual-level variation in resource selection, respectively. We analysed the data obtained during the exploratory period of six tigers and during the settled period of eight tigers separately, and compared the consequent results. We further used the settled period characteristics to model and map habitat suitability based on the Mahalanobis D2 method and the Boyce index. Results There was a clear difference in habitat selection by tigers between the exploratory and the settled period. During the exploratory period, tigers selected dense canopy and bamboo forests, but also spent time near villages and relocated village sites. However, settled tigers predominantly selected bamboo forests in complex terrain, riverine forests and teak-mixed forest, and totally avoided human settlements and agriculture areas. There were individual variations in habitat selection between exploratory and settled periods

  12. Port performance evaluation tool based on microsimulation model

    Directory of Open Access Journals (Sweden)

    Tsavalista Burhani Jzolanda

    2017-01-01

    Full Text Available As port performance is becoming correlative to national competitiveness, the issue of port performance evaluation has significantly raised. Port performances can simply be indicated by port service levels to the ship (e.g., throughput, waiting for berthing etc., as well as the utilization level of equipment and facilities within a certain period. The performances evaluation then can be used as a tool to develop related policies for improving the port’s performance to be more effective and efficient. However, the evaluation is frequently conducted based on deterministic approach, which hardly captures the nature variations of port parameters. Therefore, this paper presents a stochastic microsimulation model for investigating the impacts of port parameter variations to the port performances. The variations are derived from actual data in order to provide more realistic results. The model is further developed using MATLAB and Simulink based on the queuing theory.

  13. Mathematical modelling: a tool for hospital infection control.

    Science.gov (United States)

    Grundmann, H; Hellriegel, B

    2006-01-01

    Health-care-associated infections caused by antibiotic-resistant pathogens have become a menace in hospitals worldwide and infection control measures have lead to vastly different outcomes in different countries. During the past 6 years, a theoretical framework based on mathematical models has emerged that provides solid and testable hypotheses and opens the road to a quantitative assessment of the main obstructions that undermine current efforts to control the spread of health-care-associated infections in hospitals and communities. We aim to explain to a broader audience of professionals in health care, infection control, and health systems administration some of these models that can improve the understanding of the hidden dynamics of health-care-associated infections. We also appraise their usefulness and limitations as an innovative research and decision tool for control purposes.

  14. Rapid response tools and datasets for post-fire modeling: linking Earth Observations and process-based hydrological models to support post-fire remediation

    Science.gov (United States)

    Miller, M. E.; Billmire, M.; Elliot, W. J.; Endsley, K. A.; Robichaud, P. R.

    2015-04-01

    Preparation is key to utilizing Earth Observations and process-based models to support post-wildfire mitigation. Post-fire flooding and erosion can pose a serious threat to life, property and municipal water supplies. Increased runoff and sediment delivery due to the loss of surface cover and fire-induced changes in soil properties are of great concern. Remediation plans and treatments must be developed and implemented before the first major storms in order to be effective. One of the primary sources of information for making remediation decisions is a soil burn severity map derived from Earth Observation data (typically Landsat) that reflects fire induced changes in vegetation and soil properties. Slope, soils, land cover and climate are also important parameters that need to be considered. Spatially-explicit process-based models can account for these parameters, but they are currently under-utilized relative to simpler, lumped models because they are difficult to set up and require spatially-explicit inputs (digital elevation models, soils, and land cover). Our goal is to make process-based models more accessible by preparing spatial inputs before a fire, so that datasets can be rapidly combined with soil burn severity maps and formatted for model use. We are building an online database (http://geodjango.mtri.org/geowepp /) for the continental United States that will allow users to upload soil burn severity maps. The soil burn severity map is combined with land cover and soil datasets to generate the spatial model inputs needed for hydrological modeling of burn scars. Datasets will be created to support hydrological models, post-fire debris flow models and a dry ravel model. Our overall vision for this project is that advanced GIS surface erosion and mass failure prediction tools will be readily available for post-fire analysis using spatial information from a single online site.

  15. Watershed modeling tools and data for prognostic and diagnostic

    Science.gov (United States)

    Chambel-Leitao, P.; Brito, D.; Neves, R.

    2009-04-01

    When eutrophication is considered an important process to control it can be accomplished reducing nitrogen and phosphorus losses from both point and nonpoint sources and helping to assess the effectiveness of the pollution reduction strategy. HARP-NUT guidelines (Guidelines on Harmonized Quantification and Reporting Procedures for Nutrients) (Borgvang & Selvik, 2000) are presented by OSPAR as the best common quantification and reporting procedures for calculating the reduction of nutrient inputs. In 2000, OSPAR HARP-NUT guidelines on a trial basis. They were intended to serve as a tool for OSPAR Contracting Parties to report, in a harmonized manner, their different commitments, present or future, with regard to nutrients under the OSPAR Convention, in particular the "Strategy to Combat Eutrophication". HARP-NUT Guidelines (Borgvang and Selvik, 2000; Schoumans, 2003) were developed to quantify and report on the individual sources of nitrogen and phosphorus discharges/losses to surface waters (Source Orientated Approach). These results can be compared to nitrogen and phosphorus figures with the total riverine loads measured at downstream monitoring points (Load Orientated Approach), as load reconciliation. Nitrogen and phosphorus retention in river systems represents the connecting link between the "Source Orientated Approach" and the "Load Orientated Approach". Both approaches are necessary for verification purposes and both may be needed for providing the information required for the various commitments. Guidelines 2,3,4,5 are mainly concerned with the sources estimation. They present a set of simple calculations that allow the estimation of the origin of loads. Guideline 6 is a particular case where the application of a model is advised, in order to estimate the sources of nutrients from diffuse sources associated with land use/land cover. The model chosen for this was SWAT (Arnold & Fohrer, 2005) model because it is suggested in the guideline 6 and because it

  16. Spatially explicit methane inventory for Switzerland

    Science.gov (United States)

    Hiller, Rebecca; Bretscher, Daniel; DelSontro, Tonya; Eugster, Werner; Henne, Stephan; Henneberger, Ruth; Künzle, Thomas; Merbold, Lutz; Neininger, Bruno; Schellenberger, Andreas; Schroth, Martin; Buchmann, Nina; Brunner1, Dominik

    2013-04-01

    Spatially explicit greenhouse gas inventories are gaining in importance as a tool for policy makers to plan and control mitigation measures, and are a required input for atmospheric models used to relate atmospheric concentration measurements with upstream sources. In order to represent the high spatial heterogeneity in Switzerland, we compiled the national methane inventory into a 500 m x 500 m cadaster. In addition to the anthropogenic emissions reported to the United Nation Framework Convention on Climate Change (UNFCCC), we also included natural and semi-natural methane fluxes, i.e., emissions from lakes and reservoirs, wetlands, wild animals as well as forest uptake. Methane emissions were disaggregated according to geostatistical information about source location and extent. In Switzerland, highest methane emissions originate from the agricultural sector (152 Gg CH4 yr-1), followed by emissions from waste management (16 Gg CH4 yr-1) with highest contributions from landfills, and the energy sector (13 Gg CH4 yr-1) with highest contributions from the distribution of natural gas. Natural and semi-natural emissions only add a small amount (inventory was evaluated against methane concentrations measured from a small research aircraft (METAIR-DIMO) above the Swiss Plateau on 18 different days from May 2009 to August 2010 over. Source sensitivities of the air measured were determined by backward runs of the Lagrangian particle dispersion model FLEXPART-COSMO. Source sensitivities were multiplied with the methane inventory to derive simulated methane concentration time series. While the pattern of the variations can be reproduced well for some flight days (correlation coefficient up to 0.75), the amplitude of the variations for the simulated time series is underestimated by at least 20% suggesting an underestimation of CH4 emissions by the inventory, which is also concluded from inverse estimation using a Bayesian approach.

  17. A Model-Driven Visualization Tool for Use with Model-Based Systems Engineering Projects

    Science.gov (United States)

    Trase, Kathryn; Fink, Eric

    2014-01-01

    Model-Based Systems Engineering (MBSE) promotes increased consistency between a system's design and its design documentation through the use of an object-oriented system model. The creation of this system model facilitates data presentation by providing a mechanism from which information can be extracted by automated manipulation of model content. Existing MBSE tools enable model creation, but are often too complex for the unfamiliar model viewer to easily use. These tools do not yet provide many opportunities for easing into the development and use of a system model when system design documentation already exists. This study creates a Systems Modeling Language (SysML) Document Traceability Framework (SDTF) for integrating design documentation with a system model, and develops an Interactive Visualization Engine for SysML Tools (InVEST), that exports consistent, clear, and concise views of SysML model data. These exported views are each meaningful to a variety of project stakeholders with differing subjects of concern and depth of technical involvement. InVEST allows a model user to generate multiple views and reports from a MBSE model, including wiki pages and interactive visualizations of data. System data can also be filtered to present only the information relevant to the particular stakeholder, resulting in a view that is both consistent with the larger system model and other model views. Viewing the relationships between system artifacts and documentation, and filtering through data to see specialized views improves the value of the system as a whole, as data becomes information

  18. Slab2 - Updated subduction zone geometries and modeling tools

    Science.gov (United States)

    Portner, D. E.; Hayes, G. P.; Furtney, M.; Moore, G.; Flamme, H. E.; Hearne, M. G.

    2016-12-01

    where the model and modeling tools will be made available.

  19. Modeling of heat generations for different tool profiles in friction stir welding: study of tool geometry and contact conditions

    Directory of Open Access Journals (Sweden)

    Akindoye Waheed

    2017-04-01

    Full Text Available In this work, improved heat generation models are developed for straight and tapered shoulder geometries with different tool pin profiles in friction stir welding. The models are developed considering the welding process as a combination of the pure sliding and the pure sticking conditions. From the results, the amount of heat generation is directly proportional to the number of edges in the pin profiles in such a way that the heat generated in the profiles increases from the triangular pin profile to hexagonal pin profile. Also, increase in the tool rotational speed under constant weld speed increases the heat input while increase in the weld speed under constant tool rotational speed decreases the heat input and the rate of heat generation at the shoulder in a flat shoulder tool is more than that of conical/tapered shoulder tool. The predicted results show good agreements with the experimental results in literature.

  20. Using Modeling Tools to Better Understand Permafrost Hydrology

    Directory of Open Access Journals (Sweden)

    Clément Fabre

    2017-06-01

    Full Text Available Modification of the hydrological cycle and, subsequently, of other global cycles is expected in Arctic watersheds owing to global change. Future climate scenarios imply widespread permafrost degradation caused by an increase in air temperature, and the expected effect on permafrost hydrology is immense. This study aims at analyzing, and quantifying the daily water transfer in the largest Arctic river system, the Yenisei River in central Siberia, Russia, partially underlain by permafrost. The semi-distributed SWAT (Soil and Water Assessment Tool hydrological model has been calibrated and validated at a daily time step in historical discharge simulations for the 2003–2014 period. The model parameters have been adjusted to embrace the hydrological features of permafrost. SWAT is shown capable to estimate water fluxes at a daily time step, especially during unfrozen periods, once are considered specific climatic and soils conditions adapted to a permafrost watershed. The model simulates average annual contribution to runoff of 263 millimeters per year (mm yr−1 distributed as 152 mm yr−1 (58% of surface runoff, 103 mm yr−1 (39% of lateral flow and 8 mm yr−1 (3% of return flow from the aquifer. These results are integrated on a reduced basin area downstream from large dams and are closer to observations than previous modeling exercises.

  1. A Simple Evacuation Modeling and Simulation Tool for First Responders

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Daniel B [ORNL; Payne, Patricia W [ORNL

    2015-01-01

    Although modeling and simulation of mass evacuations during a natural or man-made disaster is an on-going and vigorous area of study, tool adoption by front-line first responders is uneven. Some of the factors that account for this situation include cost and complexity of the software. For several years, Oak Ridge National Laboratory has been actively developing the free Incident Management Preparedness and Coordination Toolkit (IMPACT) to address these issues. One of the components of IMPACT is a multi-agent simulation module for area-based and path-based evacuations. The user interface is designed so that anyone familiar with typical computer drawing tools can quickly author a geospatially-correct evacuation visualization suitable for table-top exercises. Since IMPACT is designed for use in the field where network communications may not be available, quick on-site evacuation alternatives can be evaluated to keep pace with a fluid threat situation. Realism is enhanced by incorporating collision avoidance into the simulation. Statistics are gathered as the simulation unfolds, including most importantly time-to-evacuate, to help first responders choose the best course of action.

  2. Using urban forest assessment tools to model bird habitat potential

    Science.gov (United States)

    Lerman, Susannah B.; Nislow, Keith H.; Nowak, David J.; DeStefano, Stephen; King, David I.; Jones-Farrand, D. Todd

    2014-01-01

    The alteration of forest cover and the replacement of native vegetation with buildings, roads, exotic vegetation, and other urban features pose one of the greatest threats to global biodiversity. As more land becomes slated for urban development, identifying effective urban forest wildlife management tools becomes paramount to ensure the urban forest provides habitat to sustain bird and other wildlife populations. The primary goal of this study was to integrate wildlife suitability indices to an existing national urban forest assessment tool, i-Tree. We quantified available habitat characteristics of urban forests for ten northeastern U.S. cities, and summarized bird habitat relationships from the literature in terms of variables that were represented in the i-Tree datasets. With these data, we generated habitat suitability equations for nine bird species representing a range of life history traits and conservation status that predicts the habitat suitability based on i-Tree data. We applied these equations to the urban forest datasets to calculate the overall habitat suitability for each city and the habitat suitability for different types of land-use (e.g., residential, commercial, parkland) for each bird species. The proposed habitat models will help guide wildlife managers, urban planners, and landscape designers who require specific information such as desirable habitat conditions within an urban management project to help improve the suitability of urban forests for birds.

  3. WIFIRE Data Model and Catalog for Wildfire Data and Tools

    Science.gov (United States)

    Altintas, I.; Crawl, D.; Cowart, C.; Gupta, A.; Block, J.; de Callafon, R.

    2014-12-01

    The WIFIRE project (wifire.ucsd.edu) is building an end-to-end cyberinfrastructure for real-time and data-driven simulation, prediction and visualization of wildfire behavior. WIFIRE may be used by wildfire management authorities in the future to predict wildfire rate of spread and direction, and assess the effectiveness of high-density sensor networks in improving fire and weather predictions. WIFIRE has created a data model for wildfire resources including sensed and archived data, sensors, satellites, cameras, modeling tools, workflows and social information including Twitter feeds. This data model and associated wildfire resource catalog includes a detailed description of the HPWREN sensor network, SDG&E's Mesonet, and NASA MODIS. In addition, the WIFIRE data-model describes how to integrate the data from multiple heterogeneous sources to provide detailed fire-related information. The data catalog describes 'Observables' captured by each instrument using multiple ontologies including OGC SensorML and NASA SWEET. Observables include measurements such as wind speed, air temperature, and relative humidity, as well as their accuracy and resolution. We have implemented a REST service for publishing to and querying from the catalog using Web Application Description Language (WADL). We are creating web-based user interfaces and mobile device Apps that use the REST interface for dissemination to wildfire modeling community and project partners covering academic, private, and government laboratories while generating value to emergency officials and the general public. Additionally, the Kepler scientific workflow system is instrumented to interact with this data catalog to access real-time streaming and archived wildfire data and stream it into dynamic data-driven wildfire models at scale.

  4. Crop Monitoring as a Tool for Modelling the Genesis of Millet Prices in Senegal

    Science.gov (United States)

    Jacques, D.; Marinho, E.; Defourny, P.; Waldner, F.; d'Andrimont, R.

    2015-12-01

    Food security in Sahelian countries strongly relies on the ability of markets to transfer staplesfrom surplus to deficit areas. Market failures, leading to the inefficient geographical allocation of food,are expected to emerge from high transportation costs and information asymmetries that are commonin moderately developed countries. As a result, important price differentials are observed betweenproducing and consuming areas which damages both poor producers and food insecure consumers. Itis then vital for policy makers to understand how the prices of agricultural commodities are formed byaccounting for the existing market imperfections in addition to local demand and supply considerations. To address this issue, we have gathered an unique and diversified set of data for Senegal andintegrated it in a spatially explicit model that simulates the functioning of agricultural markets, that isfully consistent with the economic theory. Our departure point is a local demand and supply modelaround each market having its catchment areas determined by the road network. We estimate the localsupply of agricultural commodities from satellite imagery while the demand is assumed to be a functionof the population living in the area. From this point on, profitable transactions between areas with lowprices to areas with high prices are simulated for different levels of per kilometer transportation costand information flows (derived from call details records i.e. mobile phone data). The simulated prices are then comparedwith the actual millet prices. Despite the parsimony of the model that estimates only two parameters, i.e. the per kilometertransportation cost and the information asymmetry resulting from low levels of mobile phone activitybetween markets, it impressively explains more than 80% of the price differentials observed in the 40markets included in the analysis. In one hand these results can be used in the assessment of the socialwelfare impacts of the further development of

  5. Assessment of the GECKO-A modeling tool using chamber observations for C12 alkanes

    Science.gov (United States)

    Aumont, B.; La, S.; Ouzebidour, F.; Valorso, R.; Mouchel-Vallon, C.; Camredon, M.; Lee-Taylor, J. M.; Hodzic, A.; Madronich, S.; Yee, L. D.; Loza, C. L.; Craven, J. S.; Zhang, X.; Seinfeld, J.

    2013-12-01

    Secondary Organic Aerosol (SOA) production and ageing is the result of atmospheric oxidation processes leading to the progressive formation of organic species with higher oxidation state and lower volatility. Explicit chemical mechanisms reflect our understanding of these multigenerational oxidation steps. Major uncertainties remain concerning the processes leading to SOA formation and the development, assessment and improvement of such explicit schemes is therefore a key issue. The development of explicit mechanism to describe the oxidation of long chain hydrocarbons is however a challenge. Indeed, explicit oxidation schemes involve a large number of reactions and secondary organic species, far exceeding the size of chemical schemes that can be written manually. The chemical mechanism generator GECKO-A (Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere) is a computer program designed to overcome this difficulty. GECKO-A generates gas phase oxidation schemes according to a prescribed protocol assigning reaction pathways and kinetics data on the basis of experimental data and structure-activity relationships. In this study, we examine the ability of the generated schemes to explain SOA formation observed in the Caltech Environmental Chambers from various C12 alkane isomers and under high NOx and low NOx conditions. First results show that the model overestimates both the SOA yields and the O/C ratios. Various sensitivity tests are performed to explore processes that might be responsible for these disagreements.

  6. A Relational Database Model and Tools for Environmental Sound Recognition

    Directory of Open Access Journals (Sweden)

    Yuksel Arslan

    2017-12-01

    Full Text Available Environmental sound recognition (ESR has become a hot topic in recent years. ESR is mainly based on machine learning (ML and ML algorithms require first a training database. This database must comprise the sounds to be recognized and other related sounds. An ESR system needs the database during training, testing and in the production stage. In this paper, we present the design and pilot establishment of a database which will assists all researchers who want to establish an ESR system. This database employs relational database model which is not used for this task before. We explain in this paper design and implementation details of the database, data collection and load process. Besides we explain the tools and developed graphical user interface for a desktop application and for the WEB.

  7. The Innsbruck/ESO sky models and telluric correction tools*

    Directory of Open Access Journals (Sweden)

    Kimeswenger S.

    2015-01-01

    While the ground based astronomical observatories just have to correct for the line-of-sight integral of these effects, the Čerenkov telescopes use the atmosphere as the primary detector. The measured radiation originates at lower altitudes and does not pass through the entire atmosphere. Thus, a decent knowledge of the profile of the atmosphere at any time is required. The latter cannot be achieved by photometric measurements of stellar sources. We show here the capabilities of our sky background model and data reduction tools for ground-based optical/infrared telescopes. Furthermore, we discuss the feasibility of monitoring the atmosphere above any observing site, and thus, the possible application of the method for Čerenkov telescopes.

  8. Nutrient dynamics management based on GIS modeling tools

    Science.gov (United States)

    Tzoraki, Ourania; Nikolaidis, Nikolaos P.; Kassotaki, Eliza; Cooper, David; Papadoulakis, Vasilis

    2013-08-01

    Nutrient sources and fate are investigated in the Evrotas, a temporary river in Greece. We assess field monitoring and modelling tools for the estimation of nutrient fate and transport through various diffuse pathways. The `total daily maximum load' approach is used to estimate the nutrient flux status by flow class and measures are recommended and applied for each flow status. Using this approach in Evrotas basin, it was estimated that almost 60% of the river network fails to meet nitrogen criteria and 50% phosphate criteria. We recommend that existing well-documented remediation measures such as reforestation of the riparian area should be implemented to achieve load reduction in close conjunction with social needs.

  9. Modeling of tool path for the CNC sheet cutting machines

    Science.gov (United States)

    Petunin, Aleksandr A.

    2015-11-01

    In the paper the problem of tool path optimization for CNC (Computer Numerical Control) cutting machines is considered. The classification of the cutting techniques is offered. We also propose a new classification of toll path problems. The tasks of cost minimization and time minimization for standard cutting technique (Continuous Cutting Problem, CCP) and for one of non-standard cutting techniques (Segment Continuous Cutting Problem, SCCP) are formalized. We show that the optimization tasks can be interpreted as discrete optimization problem (generalized travel salesman problem with additional constraints, GTSP). Formalization of some constraints for these tasks is described. For the solution GTSP we offer to use mathematical model of Prof. Chentsov based on concept of a megalopolis and dynamic programming.

  10. Prototype of Automated PLC Model Checking Using Continuous Integration Tools

    CERN Document Server

    Lettrich, Michael

    2015-01-01

    To deal with the complexity of operating and supervising large scale industrial installations at CERN, often Programmable Logic Controllers (PLCs) are used. A failure in these control systems can cause a disaster in terms of economic loses, environmental damages or human losses. Therefore the requirements to software quality are very high. To provide PLC developers with a way to verify proper functionality against requirements, a Java tool named PLCverif has been developed which encapsulates and thus simplifies the use of third party model checkers. One of our goals in this project is to integrate PLCverif in development process of PLC programs. When the developer changes the program, all the requirements should be verified again, as a change on the code can produce collateral effects and violate one or more requirements. For that reason, PLCverif has been extended to work with Jenkins CI in order to trigger automatically the verication cases when the developer changes the PLC program. This prototype has been...

  11. A crowdsourcing model for creating preclinical medical education study tools.

    Science.gov (United States)

    Bow, Hansen C; Dattilo, Jonathan R; Jonas, Andrea M; Lehmann, Christoph U

    2013-06-01

    During their preclinical course work, medical students must memorize and recall substantial amounts of information. Recent trends in medical education emphasize collaboration through team-based learning. In the technology world, the trend toward collaboration has been characterized by the crowdsourcing movement. In 2011, the authors developed an innovative approach to team-based learning that combined students' use of flashcards to master large volumes of content with a crowdsourcing model, using a simple informatics system to enable those students to share in the effort of generating concise, high-yield study materials. The authors used Google Drive and developed a simple Java software program that enabled students to simultaneously access and edit sets of questions and answers in the form of flashcards. Through this crowdsourcing model, medical students in the class of 2014 at the Johns Hopkins University School of Medicine created a database of over 16,000 questions that corresponded to the Genes to Society basic science curriculum. An analysis of exam scores revealed that students in the class of 2014 outperformed those in the class of 2013, who did not have access to the flashcard system, and a survey of students demonstrated that users were generally satisfied with the system and found it a valuable study tool. In this article, the authors describe the development and implementation of their crowdsourcing model for creating study materials, emphasize its simplicity and user-friendliness, describe its impact on students' exam performance, and discuss how students in any educational discipline could implement a similar model of collaborative learning.

  12. Tools and Models for Integrating Multiple Cellular Networks

    Energy Technology Data Exchange (ETDEWEB)

    Gerstein, Mark [Yale Univ., New Haven, CT (United States). Gerstein Lab.

    2015-11-06

    In this grant, we have systematically investigated the integrated networks, which are responsible for the coordination of activity between metabolic pathways in prokaryotes. We have developed several computational tools to analyze the topology of the integrated networks consisting of metabolic, regulatory, and physical interaction networks. The tools are all open-source, and they are available to download from Github, and can be incorporated in the Knowledgebase. Here, we summarize our work as follow. Understanding the topology of the integrated networks is the first step toward understanding its dynamics and evolution. For Aim 1 of this grant, we have developed a novel algorithm to determine and measure the hierarchical structure of transcriptional regulatory networks [1]. The hierarchy captures the direction of information flow in the network. The algorithm is generally applicable to regulatory networks in prokaryotes, yeast and higher organisms. Integrated datasets are extremely beneficial in understanding the biology of a system in a compact manner due to the conflation of multiple layers of information. Therefore for Aim 2 of this grant, we have developed several tools and carried out analysis for integrating system-wide genomic information. To make use of the structural data, we have developed DynaSIN for protein-protein interactions networks with various dynamical interfaces [2]. We then examined the association between network topology with phenotypic effects such as gene essentiality. In particular, we have organized E. coli and S. cerevisiae transcriptional regulatory networks into hierarchies. We then correlated gene phenotypic effects by tinkering with different layers to elucidate which layers were more tolerant to perturbations [3]. In the context of evolution, we also developed a workflow to guide the comparison between different types of biological networks across various species using the concept of rewiring [4], and Furthermore, we have developed

  13. Enabling analytical and Modeling Tools for Enhanced Disease Surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Dawn K. Manley

    2003-04-01

    Early detection, identification, and warning are essential to minimize casualties from a biological attack. For covert attacks, sick people are likely to provide the first indication of an attack. An enhanced medical surveillance system that synthesizes distributed health indicator information and rapidly analyzes the information can dramatically increase the number of lives saved. Current surveillance methods to detect both biological attacks and natural outbreaks are hindered by factors such as distributed ownership of information, incompatible data storage and analysis programs, and patient privacy concerns. Moreover, because data are not widely shared, few data mining algorithms have been tested on and applied to diverse health indicator data. This project addressed both integration of multiple data sources and development and integration of analytical tools for rapid detection of disease outbreaks. As a first prototype, we developed an application to query and display distributed patient records. This application incorporated need-to-know access control and incorporated data from standard commercial databases. We developed and tested two different algorithms for outbreak recognition. The first is a pattern recognition technique that searches for space-time data clusters that may signal a disease outbreak. The second is a genetic algorithm to design and train neural networks (GANN) that we applied toward disease forecasting. We tested these algorithms against influenza, respiratory illness, and Dengue Fever data. Through this LDRD in combination with other internal funding, we delivered a distributed simulation capability to synthesize disparate information and models for earlier recognition and improved decision-making in the event of a biological attack. The architecture incorporates user feedback and control so that a user's decision inputs can impact the scenario outcome as well as integrated security and role-based access-control for communicating

  14. Uncertainty Analysis of Coupled Socioeconomic-Cropping Models: Building Confidence in Climate Change Decision-Support Tools for Local Stakeholders

    Science.gov (United States)

    Malard, J. J.; Rojas, M.; Adamowski, J. F.; Gálvez, J.; Tuy, H. A.; Melgar-Quiñonez, H.

    2015-12-01

    While cropping models represent the biophysical aspects of agricultural systems, system dynamics modelling offers the possibility of representing the socioeconomic (including social and cultural) aspects of these systems. The two types of models can then be coupled in order to include the socioeconomic dimensions of climate change adaptation in the predictions of cropping models.We develop a dynamically coupled socioeconomic-biophysical model of agricultural production and its repercussions on food security in two case studies from Guatemala (a market-based, intensive agricultural system and a low-input, subsistence crop-based system). Through the specification of the climate inputs to the cropping model, the impacts of climate change on the entire system can be analysed, and the participatory nature of the system dynamics model-building process, in which stakeholders from NGOs to local governmental extension workers were included, helps ensure local trust in and use of the model.However, the analysis of climate variability's impacts on agroecosystems includes uncertainty, especially in the case of joint physical-socioeconomic modelling, and the explicit representation of this uncertainty in the participatory development of the models is important to ensure appropriate use of the models by the end users. In addition, standard model calibration, validation, and uncertainty interval estimation techniques used for physically-based models are impractical in the case of socioeconomic modelling. We present a methodology for the calibration and uncertainty analysis of coupled biophysical (cropping) and system dynamics (socioeconomic) agricultural models, using survey data and expert input to calibrate and evaluate the uncertainty of the system dynamics as well as of the overall coupled model. This approach offers an important tool for local decision makers to evaluate the potential impacts of climate change and their feedbacks through the associated socioeconomic system.

  15. Explicit reduced reaction models for ignition, flame propagation, and extinction of C{sub 2}H{sub 4}/CH{sub 4}/H{sub 2} and air systems

    Energy Technology Data Exchange (ETDEWEB)

    Zambon, A.C.; Chelliah, H.K. [Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904-4746 (United States)

    2007-07-15

    Large-scale simulations of multidimensional unsteady reacting flows with detailed chemistry and transport can be computationally extremely intensive even on distributed computing architectures. With the development of computationally efficient reduced chemical kinetic models, the smaller number of scalar variables to be integrated can lead to a significant reduction in the computational time required for the simulation with limited loss of accuracy in the results. A general MATLAB-based automated procedure for the development of reduced reaction models is presented. Based on the application of the quasi-steady-state (QSS) approximation for certain chemical species and on the elimination of selected fast elementary reactions, any complex starting reaction mechanism (detailed or skeletal) can be reduced with minimal human intervention. A key feature of the reduction procedure is the decoupling of the QSS species appearing in the QSS algebraic relations, enabling the explicit solution of the QSS species concentrations, which are needed for the evaluation of the elementary reaction rates. In contrast, previous approaches mainly relied on an implicit solution, requiring computationally intensive inner iterations. The automated procedure is first tested with the generation of an implicit 5-step reduced reaction model for CH{sub 4}/air flame propagation. Next, two explicit robust reduced reaction models based on ignition data (18-step) and on flame propagation data (15-step) are systematically developed and extensively validated for ignition delay time, flame propagation, and extinction predictions of C{sub 2}H{sub 4}/air, CH{sub 4}/air, and H{sub 2}/air systems over a wide range of equivalence ratios, initial temperatures, pressures, and strain rates. In order to assess the computational advantages of the explicit reduced reaction models, comparisons of the computational time required to evaluate the chemical source terms as well as for the integration of unsteady

  16. Explicit solvers in an implicit code

    Science.gov (United States)

    Martinez Montesinos, Beatriz; Kaus, Boris J. P.; Popov, Anton

    2017-04-01

    Many geodynamic processes occur over long timescales (millions of years), and are best solved with implicit solvers. Yet, some processes, such as hydrofracking, or wave propagation, occur over smaller timescales. In those cases, it might be advantageous to use an explicit rather than an implicit approach as it requires significantly less memory and computational costs. Here, we discuss our ongoing work to include explicit solvers in the parallel software package LaMEM (Lithosphere and Mantle Evolution Model). As a first step, we focus on modelling seismic wave propagation in heterogeneous 3D poro-elasto-plastic models. To do that, we add inertial terms to the momentum equations as well as elastic compressibility to the mass conservation equations in an explicit way using the staggered grid finite difference discretization method. Results are similar to that of existing wave propagation codes and are capable to simulate wave propagation in heterogeneous media. To simulate geomechanical problems, timestep restrictions posed by the seismic wave speed are usually too severe to allow simulating deformation on a timescale of months-years. The classical (FLAC) method introduces a mass-density scaling in which a non-physical (larger) density is employed in the momentum equations. We will discuss how this method fits simple benchmarks for elastic and elastoplastic deformation. As an application, we use the code to model different complex media subject to compression and we investigate how mass scaling influence in our results.

  17. Single Event Kinetic Modelling without Explicit Generation of Large Networks: Application to Hydrocracking of Long Paraffins Modélisation cinétique par événements constitutifs sans génération explicite de grands réseaux : application à l’hydrocraquage des paraffines longues

    Directory of Open Access Journals (Sweden)

    Guillaume D.

    2011-08-01

    Full Text Available The single event modelling concept allows developing kinetic models for the simulation of refinery processes. For reaction networks with several hundreds of thousands of species, as is the case for catalytic reforming, rigorous relumping by carbon atom number and branching degree were efficiently employed by assuming chemical equilibrium in each lump. This relumping technique yields a compact lumped model without any loss of information, but requires the full detail of an explicitly generated reaction network. Classic network generation techniques become impractical when the hydrocarbon species contain more than approximately 20 carbon atoms, because of the extremely rapid growth of reaction network. Hence, implicit relumping techniques were developed in order to compute lumping coefficients without generating the detailed reaction network. Two alternative and equivalent approaches are presented, based either on structural classes or on lateral chain decomposition. These two methods are discussed and the lateral chain decomposition method is applied to the kinetic modelling of long chain paraffin hydroisomerization and hydrocracking. The lateral chain decomposition technique is exactly equivalent to the original calculation method based on the explicitly generated detailed reaction network, as long as Benson’s group contribution method is used to calculate the necessary thermodynamic data in both approaches. Le concept de modélisation par événements constitutifs permet de développer des modèles cinétiques pour la simulation des procédés de raffinage. Pour des réseaux réactionnels de centaines de milliers d'espèces, comme cela est le cas pour le reformage catalytique, le regroupement rigoureux par nombre d'atomes de carbone et degré de ramification a été utilisé efficacement en faisant l'hypothèse de l'équilibre chimique dans chaque groupe. Cette technique de regroupement conduit à un modèle regroupé compact sans perte d

  18. Improving Power System Modeling. A Tool to Link Capacity Expansion and Production Cost Models

    Energy Technology Data Exchange (ETDEWEB)

    Diakov, Victor [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cole, Wesley [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sullivan, Patrick [National Renewable Energy Lab. (NREL), Golden, CO (United States); Brinkman, Gregory [National Renewable Energy Lab. (NREL), Golden, CO (United States); Margolis, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-11-01

    Capacity expansion models (CEM) provide a high-level long-term view at the prospects of the evolving power system. In simulating the possibilities of long-term capacity expansion, it is important to maintain the viability of power system operation in the short-term (daily, hourly and sub-hourly) scales. Production-cost models (PCM) simulate routine power system operation on these shorter time scales using detailed load, transmission and generation fleet data by minimizing production costs and following reliability requirements. When based on CEM 'predictions' about generating unit retirements and buildup, PCM provide more detailed simulation for the short-term system operation and, consequently, may confirm the validity of capacity expansion predictions. Further, production cost model simulations of a system that is based on capacity expansion model solution are 'evolutionary' sound: the generator mix is the result of logical sequence of unit retirement and buildup resulting from policy and incentives. The above has motivated us to bridge CEM with PCM by building a capacity expansion - to - production cost model Linking Tool (CEPCoLT). The Linking Tool is built to onset capacity expansion model prescriptions onto production cost model inputs. NREL's ReEDS and Energy Examplar's PLEXOS are the capacity expansion and the production cost models, respectively. Via the Linking Tool, PLEXOS provides details of operation for the regionally-defined ReEDS scenarios.

  19. Tool use in computer-based learning environments: Adopting and extending the technology acceptance model

    OpenAIRE

    Juarez Collazo, N. A.; Wu, X.; Elen, J.; G. Clarebout

    2014-01-01

    This study adopts the Technology Acceptance Model (TAM) and extends it to study the effects of different variables on tool use. The influence of perceptions on tool use was studied in two different conditions: with and without explanation of the tool functionality. As an external variable, self-efficacy was entered in the TAM and the main research question thus focused on the mediating effects of perceptions (perceived tool functionality and perceived tool usability) between self-efficacy on ...

  20. A New Climate Adjustment Tool: An update to EPA’s Storm Water Management Model

    Science.gov (United States)

    The US EPA’s newest tool, the Stormwater Management Model (SWMM) – Climate Adjustment Tool (CAT) is meant to help municipal stormwater utilities better address potential climate change impacts affecting their operations.

  1. Age effects on explicit and implicit memory

    Directory of Open Access Journals (Sweden)

    Emma eWard

    2013-09-01

    Full Text Available It is well documented that explicit memory (e.g., recognition declines with age. In contrast, many argue that implicit memory (e.g., priming is preserved in healthy aging. For example, priming on tasks such as perceptual identification is often not statistically different in groups of young and older adults. Such observations are commonly taken as evidence for distinct explicit and implicit learning/memory systems. In this article we discuss several lines of evidence that challenge this view. We describe how patterns of differential age-related decline may arise from differences in the ways in which the two forms of memory are commonly measured, and review recent research suggesting that under improved measurement methods, implicit memory is not age-invariant. Formal computational models are of considerable utility in revealing the nature of underlying systems. We report the results of applying single and multiple-systems models to data on age effects in implicit and explicit memory. Model comparison clearly favours the single-system view. Implications for the memory systems debate are discussed.

  2. Analytical Modeling Tool for Design of Hydrocarbon Sensitive Optical Fibers

    Directory of Open Access Journals (Sweden)

    Khalil Al Handawi

    2017-09-01

    Full Text Available Pipelines are the main transportation means for oil and gas products across large distances. Due to the severe conditions they operate in, they are regularly inspected using conventional Pipeline Inspection Gages (PIGs for corrosion damage. The motivation for researching a real-time distributed monitoring solution arose to mitigate costs and provide a proactive indication of potential failures. Fiber optic sensors with polymer claddings provide a means of detecting contact with hydrocarbons. By coating the fibers with a layer of metal similar in composition to that of the parent pipeline, corrosion of this coating may be detected when the polymer cladding underneath is exposed to the surrounding hydrocarbons contained within the pipeline. A Refractive Index (RI change occurs in the polymer cladding causing a loss in intensity of a traveling light pulse due to a reduction in the fiber’s modal capacity. Intensity losses may be detected using Optical Time Domain Reflectometry (OTDR while pinpointing the spatial location of the contact via time delay calculations of the back-scattered pulses. This work presents a theoretical model for the above sensing solution to provide a design tool for the fiber optic cable in the context of hydrocarbon sensing following corrosion of an external metal coating. Results are verified against the experimental data published in the literature.

  3. Model base SRAF insertion check with OPC verify tools

    Science.gov (United States)

    Hung, Chi-Yuan; Deng, Zexi; Gao, Gensheng; Zhang, Liguo; Liu, Qingwei

    2006-05-01

    With the critical dimension of IC design decreases dramatically, to meet the yield target of the manufacture process, resolution enhancement technologies become extremely important nowadays. For 90nm technology node and below, sub rule assistant feature (SRAF) are usually employed to enhance the robustness of the micro lithography process. SRAF is really a powerful methodology to push the process limit for given equipment conditions. However, there is also a drawback of the SRAF. It is very hard to check the reasonability of the SRAF location, especially when SRAF is applied on full chips. This work is trying to demonstrate a model-based approach to do full-chip check of the SRAF insertion rule. First, we try to capture the lithography process information through real empirical wafer data. Then we try to check every SRAFs location and to find any hot spot that has the risk of being printed out on the wafer. Based on this approach, we can then not only apply full chip check to reduce the printability of SRAF. Furthermore, combined with DRC tools, we can find SRAFs that are inserted unreasonably and then apply modification on them.

  4. Accelerated bridge construction (ABC) decision making and economic modeling tool.

    Science.gov (United States)

    2011-12-01

    In this FHWA-sponsored pool funded study, a set of decision making tools, based on the Analytic Hierarchy Process (AHP) was developed. This tool set is prepared for transportation specialists and decision-makers to determine if ABC is more effective ...

  5. Transgenic Mouse Models of Alzheimer Disease: Developing a Better Model as a Tool for Therapeutic Interventions

    Science.gov (United States)

    Kitazawa, Masashi; Medeiros, Rodrigo; LaFerla, Frank M.

    2015-01-01

    Alzheimer disease (AD) is the leading cause of dementia among elderly. Currently, no effective treatment is available for AD. Analysis of transgenic mouse models of AD has facilitated our understanding of disease mechanisms and provided valuable tools for evaluating potential therapeutic strategies. In this review, we will discuss the strengths and weaknesses of current mouse models of AD and the contribution towards understanding the pathological mechanisms and developing effective therapies. PMID:22288400

  6. Detecting Surgical Tools by Modelling Local Appearance and Global Shape.

    Science.gov (United States)

    Bouget, David; Benenson, Rodrigo; Omran, Mohamed; Riffaud, Laurent; Schiele, Bernt; Jannin, Pierre

    2015-12-01

    Detecting tools in surgical videos is an important ingredient for context-aware computer-assisted surgical systems. To this end, we present a new surgical tool detection dataset and a method for joint tool detection and pose estimation in 2d images. Our two-stage pipeline is data-driven and relaxes strong assumptions made by previous works regarding the geometry, number, and position of tools in the image. The first stage classifies each pixel based on local appearance only, while the second stage evaluates a tool-specific shape template to enforce global shape. Both local appearance and global shape are learned from training data. Our method is validated on a new surgical tool dataset of 2 476 images from neurosurgical microscopes, which is made freely available. It improves over existing datasets in size, diversity and detail of annotation. We show that our method significantly improves over competitive baselines from the computer vision field. We achieve 15% detection miss-rate at 10(-1) false positives per image (for the suction tube) over our surgical tool dataset. Results indicate that performing semantic labelling as an intermediate task is key for high quality detection.

  7. Enhancing Formal Modelling Tool Support with Increased Automation

    DEFF Research Database (Denmark)

    Lausdahl, Kenneth

    Progress report for the qualification exam report for PhD Student Kenneth Lausdahl. Initial work on enhancing tool support for the formal method VDM and the concept of unifying a abstract syntax tree with the ability for isolated extensions is described. The tool support includes a connection to ...... to UML and a test automation principle based on traces written as a kind of regular expressions....

  8. Meteoric 10Be as a tool to investigate human induced soil fluxes: a conceptual model

    Science.gov (United States)

    Campforts, Benjamin; Govers, Gerard; Vanacker, Veerle; De Vente, Joris; Boix-Fayos, Carolina; Minella, Jean; Baken, Stijn; Smolders, Erik

    2014-05-01

    The use of meteoric 10Be as a tool to understand long term landscape behavior is becoming increasingly popular. Due its high residence time, meteoric 10Be allows in principle to investigate in situ erosion rates over time scales exceeding the period studied with classical approaches such as 137Cs. The use of meteoric 10Be strongly contributes to the traditional interpretation of sedimentary archives which cannot be unequivocally coupled to sediment production and could provide biased information over longer time scales (Sadler, 1981). So far, meteoric 10Be has successfully been used in geochemical fingerprinting of sediments, to date soil profiles, to assess soil residence times and to quantify downslope soil fluxes using accumulated 10Be inventories along a hill slope. However, less attention is given to the potential use of the tracer to directly asses human induced changes in soil fluxes through deforestation, cultivation and reforestation. A good understanding of the processes governing the distribution of meteoric 10Be both within the soil profile and at landscape scale is essential before meteoric 10Be can be successfully applied to assess human impact. We developed a spatially explicit 2D-model (Be2D) in order to gain insight in meteoric 10Be movement along a hillslope that is subject to human disturbance. Be2D integrates both horizontal soil fluxes and vertical meteoric 10Be movement throughout the soil prolife. Horizontal soil fluxes are predicted using (i) well studied geomorphical laws for natural erosion and soil formation as well as (ii) human accelerated water and tillage erosion. Vertical movement of meteoric 10Be throughout the soil profile is implemented by inserting depth dependent retardation calculated using experimentally determined partition coefficients (Kd). The model was applied to different environments such as (i) the Belgian loess belt, characterized by aeolian deposits enriched in inherited meteoric 10Be, (ii) highly degraded and stony

  9. Spatially explicit spectral analysis of point clouds and geospatial data

    Science.gov (United States)

    Buscombe, Daniel

    2016-01-01

    The increasing use of spatially explicit analyses of high-resolution spatially distributed data (imagery and point clouds) for the purposes of characterising spatial heterogeneity in geophysical phenomena necessitates the development of custom analytical and computational tools. In recent years, such analyses have become the basis of, for example, automated texture characterisation and segmentation, roughness and grain size calculation, and feature detection and classification, from a variety of data types. In this work, much use has been made of statistical descriptors of localised spatial variations in amplitude variance (roughness), however the horizontal scale (wavelength) and spacing of roughness elements is rarely considered. This is despite the fact that the ratio of characteristic vertical to horizontal scales is not constant and can yield important information about physical scaling relationships. Spectral analysis is a hitherto under-utilised but powerful means to acquire statistical information about relevant amplitude and wavelength scales, simultaneously and with computational efficiency. Further, quantifying spatially distributed data in the frequency domain lends itself to the development of stochastic models for probing the underlying mechanisms which govern the spatial distribution of geological and geophysical phenomena. The software package PySESA (Python program for Spatially Explicit Spectral Analysis) has been developed for generic analyses of spatially distributed data in both the spatial and frequency domains. Developed predominantly in Python, it accesses libraries written in Cython and C++ for efficiency. It is open source and modular, therefore readily incorporated into, and combined with, other data analysis tools and frameworks with particular utility for supporting research in the fields of geomorphology, geophysics, hydrography, photogrammetry and remote sensing. The analytical and computational structure of the toolbox is described

  10. Spatially explicit spectral analysis of point clouds and geospatial data

    Science.gov (United States)

    Buscombe, Daniel D.

    2015-01-01

    The increasing use of spatially explicit analyses of high-resolution spatially distributed data (imagery and point clouds) for the purposes of characterising spatial heterogeneity in geophysical phenomena necessitates the development of custom analytical and computational tools. In recent years, such analyses have become the basis of, for example, automated texture characterisation and segmentation, roughness and grain size calculation, and feature detection and classification, from a variety of data types. In this work, much use has been made of statistical descriptors of localised spatial variations in amplitude variance (roughness), however the horizontal scale (wavelength) and spacing of roughness elements is rarely considered. This is despite the fact that the ratio of characteristic vertical to horizontal scales is not constant and can yield important information about physical scaling relationships. Spectral analysis is a hitherto under-utilised but powerful means to acquire statistical information about relevant amplitude and wavelength scales, simultaneously and with computational efficiency. Further, quantifying spatially distributed data in the frequency domain lends itself to the development of stochastic models for probing the underlying mechanisms which govern the spatial distribution of geological and geophysical phenomena. The software packagePySESA (Python program for Spatially Explicit Spectral Analysis) has been developed for generic analyses of spatially distributed data in both the spatial and frequency domains. Developed predominantly in Python, it accesses libraries written in Cython and C++ for efficiency. It is open source and modular, therefore readily incorporated into, and combined with, other data analysis tools and frameworks with particular utility for supporting research in the fields of geomorphology, geophysics, hydrography, photogrammetry and remote sensing. The analytical and computational structure of the toolbox is

  11. Hypersonic Control Modeling and Simulation Tool for Lifting Towed Ballutes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Aerospace Corporation proposes to develop a hypersonic control modeling and simulation tool for hypersonic aeroassist vehicles. Our control and simulation...

  12. Explicit Oral Narrative Intervention for Students with Williams Syndrome

    Directory of Open Access Journals (Sweden)

    Eliseo Diez-Itza

    2018-01-01

    Full Text Available Narrative skills play a crucial role in organizing experience, facilitating social interaction and building academic discourse and literacy. They are at the interface of cognitive, social, and linguistic abilities related to school engagement. Despite their relative strengths in social and grammatical skills, students with Williams syndrome (WS do not show parallel cognitive and pragmatic performance in narrative generation tasks. The aim of the present study was to assess retelling of a TV cartoon tale and the effect of an individualized explicit instruction of the narrative structure. Participants included eight students with WS who attended different special education levels. Narratives were elicited in two sessions (pre and post intervention, and were transcribed, coded and analyzed using the tools of the CHILDES Project. Narratives were coded for productivity and complexity at the microstructure and macrostructure levels. Microstructure productivity (i.e., length of narratives included number of utterances, clauses, and tokens. Microstructure complexity included mean length of utterances, lexical diversity and use of discourse markers as cohesive devices. Narrative macrostructure was assessed for textual coherence through the Pragmatic Evaluation Protocol for Speech Corpora (PREP-CORP. Macrostructure productivity and complexity included, respectively, the recall and sequential order of scenarios, episodes, events and characters. A total of four intervention sessions, lasting approximately 20 min, were delivered individually once a week. This brief intervention addressed explicit instruction about the narrative structure and the use of specific discourse markers to improve cohesion of story retellings. Intervention strategies included verbal scaffolding and modeling, conversational context for retelling the story and visual support with pictures printed from the cartoon. Results showed significant changes in WS students’ retelling of the

  13. Explicit Oral Narrative Intervention for Students with Williams Syndrome

    Science.gov (United States)

    Diez-Itza, Eliseo; Martínez, Verónica; Pérez, Vanesa; Fernández-Urquiza, Maite

    2018-01-01

    Narrative skills play a crucial role in organizing experience, facilitating social interaction and building academic discourse and literacy. They are at the interface of cognitive, social, and linguistic abilities related to school engagement. Despite their relative strengths in social and grammatical skills, students with Williams syndrome (WS) do not show parallel cognitive and pragmatic performance in narrative generation tasks. The aim of the present study was to assess retelling of a TV cartoon tale and the effect of an individualized explicit instruction of the narrative structure. Participants included eight students with WS who attended different special education levels. Narratives were elicited in two sessions (pre and post intervention), and were transcribed, coded and analyzed using the tools of the CHILDES Project. Narratives were coded for productivity and complexity at the microstructure and macrostructure levels. Microstructure productivity (i.e., length of narratives) included number of utterances, clauses, and tokens. Microstructure complexity included mean length of utterances, lexical diversity and use of discourse markers as cohesive devices. Narrative macrostructure was assessed for textual coherence through the Pragmatic Evaluation Protocol for Speech Corpora (PREP-CORP). Macrostructure productivity and complexity included, respectively, the recall and sequential order of scenarios, episodes, events and characters. A total of four intervention sessions, lasting approximately 20 min, were delivered individually once a week. This brief intervention addressed explicit instruction about the narrative structure and the use of specific discourse markers to improve cohesion of story retellings. Intervention strategies included verbal scaffolding and modeling, conversational context for retelling the story and visual support with pictures printed from the cartoon. Results showed significant changes in WS students’ retelling of the story, both at

  14. Towards an explicit account of implicit learning.

    Science.gov (United States)

    Forkstam, Christian; Petersson, Karl Magnus

    2005-08-01

    The human brain supports acquisition mechanisms that can extract structural regularities implicitly from experience without the induction of an explicit model. Reber defined the process by which an individual comes to respond appropriately to the statistical structure of the input ensemble as implicit learning. He argued that the capacity to generalize to new input is based on the acquisition of abstract representations that reflect underlying structural regularities in the acquisition input. We focus this review of the implicit learning literature on studies published during 2004 and 2005. We will not review studies of repetition priming ('implicit memory'). Instead we focus on two commonly used experimental paradigms: the serial reaction time task and artificial grammar learning. Previous comprehensive reviews can be found in Seger's 1994 article and the Handbook of Implicit Learning. Emerging themes include the interaction between implicit and explicit processes, the role of the medial temporal lobe, developmental aspects of implicit learning, age-dependence, the role of sleep and consolidation. The attempts to characterize the interaction between implicit and explicit learning are promising although not well understood. The same can be said about the role of sleep and consolidation. Despite the fact that lesion studies have relatively consistently suggested that the medial temporal lobe memory system is not necessary for implicit learning, a number of functional magnetic resonance studies have reported medial temporal lobe activation in implicit learning. This issue merits further research. Finally, the clinical relevance of implicit learning remains to be determined.

  15. Examining an important urban transportation management tool: subarea modeling

    Directory of Open Access Journals (Sweden)

    Xueming CHEN

    2009-12-01

    Full Text Available At present, customized subarea models have been widely used in local transportation planning throughout the United States. The biggest strengths of a subarea model lie in its more detailed and accurate modeling outputs which better meet local planning requirements. In addition, a subarea model can substantially reduce database size and model running time. In spite of these advantages, subarea models remain quite weak in maintaining consistency with a regional model, modeling transit projects, smart growth measures, air quality conformity, and other areas. Both opportunities and threats exist for subarea modeling. In addition to examining subarea models, this paper introduces the decision-making process in choosing a proper subarea modeling approach (windowing versus focusing and software package. This study concludes that subarea modeling will become more popular in the future. More GIS applications, travel surveys, transit modeling, microsimulation software utilization, and other modeling improvements are expected to be incorporated into the subarea modeling process.

  16. Potential for progress in carbon cycle modeling: models as tools and representations of reality (Invited)

    Science.gov (United States)

    Caldeira, K.

    2013-12-01

    Some carbon cycle modelers conceive of themselves as developing a representation of reality that will serve as a general purpose tool that can be used to make a wide variety of predictions. However, models are tools used to solve particular problems. If we were to ask, 'what tool is best for fastening two pieces of wood together,' depending on the circumstances that tool could be hammer, a screw driver, or perhaps some sort of glue gun. And the best kind of screw driver might depend on whether we were thinking about Philips or flat headed screws. If there is no unique answer to the question of which type of tool is best for fastening two pieces of wood together, surely there is no unique answer to the question of which type of model is best for making carbon-cycle predictions. We must first understand what problem we are trying to solve. Some modeling studies try to make the most reliable projections, considering as many processes and predicting as many observables as possible, whereas other modeling studies try to show how general trends depend on relatively few (perhaps highly aggregated) processes. This talk will look at CMIP5 carbon-cycle model results and address the issue of the extent to which the overall global-scale trends projected by these detailed models might projected by models with many fewer degrees of freedom. It should be noted that an ocean carbon-cycle model that predicts many observables at local scale is much more easily falsified (and thus in some sense is more ';scientific') than an ocean model that predicts only global scale phenomena. Nevertheless, if all that is needed is a crude estimate of global ocean CO2 uptake (say, to permit as study of the carbon-cycle on land), a simple representation of the ocean carbon cycle may suffice. This talk will take as its jumping off point two quotes: 'All models are wrong, some are useful.' - George E.P. Box 'Models should be as simple as possible but no simpler.' - Albert Einstein (likely an erroneous

  17. Tool-Body Assimilation Model Based on Body Babbling and Neurodynamical System

    Directory of Open Access Journals (Sweden)

    Kuniyuki Takahashi

    2015-01-01

    Full Text Available We propose the new method of tool use with a tool-body assimilation model based on body babbling and a neurodynamical system for robots to use tools. Almost all existing studies for robots to use tools require predetermined motions and tool features; the motion patterns are limited and the robots cannot use novel tools. Other studies fully search for all available parameters for novel tools, but this leads to massive amounts of calculations. To solve these problems, we took the following approach: we used a humanoid robot model to generate random motions based on human body babbling. These rich motion experiences were used to train recurrent and deep neural networks for modeling a body image. Tool features were self-organized in parametric bias, modulating the body image according to the tool in use. Finally, we designed a neural network for the robot to generate motion only from the target image. Experiments were conducted with multiple tools for manipulating a cylindrical target object. The results show that the tool-body assimilation model is capable of motion generation.

  18. Development of a resource modelling tool to support decision makers in pandemic influenza preparedness: The AsiaFluCap Simulator.

    Science.gov (United States)

    Stein, Mart Lambertus; Rudge, James W; Coker, Richard; van der Weijden, Charlie; Krumkamp, Ralf; Hanvoravongchai, Piya; Chavez, Irwin; Putthasri, Weerasak; Phommasack, Bounlay; Adisasmito, Wiku; Touch, Sok; Sat, Le Minh; Hsu, Yu-Chen; Kretzschmar, Mirjam; Timen, Aura

    2012-10-12

    Health care planning for pandemic influenza is a challenging task which requires predictive models by which the impact of different response strategies can be evaluated. However, current preparedness plans and simulations exercises, as well as freely available simulation models previously made for policy makers, do not explicitly address the availability of health care resources or determine the impact of shortages on public health. Nevertheless, the feasibility of health systems to implement response measures or interventions described in plans and trained in exercises depends on the available resource capacity. As part of the AsiaFluCap project, we developed a comprehensive and flexible resource modelling tool to support public health officials in understanding and preparing for surges in resource demand during future pandemics. The AsiaFluCap Simulator is a combination of a resource model containing 28 health care resources and an epidemiological model. The tool was built in MS Excel© and contains a user-friendly interface which allows users to select mild or severe pandemic scenarios, change resource parameters and run simulations for one or multiple regions. Besides epidemiological estimations, the simulator provides indications on resource gaps or surpluses, and the impact of shortages on public health for each selected region. It allows for a comparative analysis of the effects of resource availability and consequences of different strategies of resource use, which can provide guidance on resource prioritising and/or mobilisation. Simulation results are displayed in various tables and graphs, and can also be easily exported to GIS software to create maps for geographical analysis of the distribution of resources. The AsiaFluCap Simulator is freely available software (http://www.cdprg.org) which can be used by policy makers, policy advisors, donors and other stakeholders involved in preparedness for providing evidence based and illustrative information on

  19. Development of a resource modelling tool to support decision makers in pandemic influenza preparedness: The AsiaFluCap Simulator

    Directory of Open Access Journals (Sweden)

    Stein Mart

    2012-10-01

    Full Text Available Abstract Background Health care planning for pandemic influenza is a challenging task which requires predictive models by which the impact of different response strategies can be evaluated. However, current preparedness plans and simulations exercises, as well as freely available simulation models previously made for policy makers, do not explicitly address the availability of health care resources or determine the impact of shortages on public health. Nevertheless, the feasibility of health systems to implement response measures or interventions described in plans and trained in exercises depends on the available resource capacity. As part of the AsiaFluCap project, we developed a comprehensive and flexible resource modelling tool to support public health officials in understanding and preparing for surges in resource demand during future pandemics. Results The AsiaFluCap Simulator is a combination of a resource model containing 28 health care resources and an epidemiological model. The tool was built in MS Excel© and contains a user-friendly interface which allows users to select mild or severe pandemic scenarios, change resource parameters and run simulations for one or multiple regions. Besides epidemiological estimations, the simulator provides indications on resource gaps or surpluses, and the impact of shortages on public health for each selected region. It allows for a comparative analysis of the effects of resource availability and consequences of different strategies of resource use, which can provide guidance on resource prioritising and/or mobilisation. Simulation results are displayed in various tables and graphs, and can also be easily exported to GIS software to create maps for geographical analysis of the distribution of resources. Conclusions The AsiaFluCap Simulator is freely available software (http://www.cdprg.org which can be used by policy makers, policy advisors, donors and other stakeholders involved in preparedness for

  20. Regional-scale scenario modeling for coral reefs: a decision support tool to inform management of a complex system.

    Science.gov (United States)

    Melbourne-Thomas, Jessica; Johnson, Craig R; Fung, Tak; Seymour, Robert M; Chérubin, Laurent M; Arias-González, J Ernesto; Fulton, Elizabeth A

    2011-06-01

    The worldwide decline of coral reefs threatens the livelihoods of coastal communities and puts at risk valuable ecosystem services provided by reefs. There is a pressing need for robust predictions of potential futures of coral reef and associated human systems under alternative management scenarios. Understanding and predicting the dynamics of coral reef systems at regional scales of tens to hundreds of kilometers is imperative, because reef systems are connected by physical and socioeconomic processes across regions and often across international boundaries. We present a spatially explicit regional-scale model of ecological dynamics for a general coral reef system. In designing our model as a tool for decision support, we gave precedence to portability and accessibility; the model can be parameterized for dissimilar coral reef systems in different parts of the world, and the model components and outputs are understandable for nonexperts. The model simulates local-scale dynamics, which are coupled across regions through larval connectivity between reefs. We validate our model using an instantiation for the Meso-American Reef system. The model realistically captures local and regional ecological dynamics and responds to external forcings in the form of harvesting, pollution, and physical damage (e.g., hurricanes, coral bleaching) to produce trajectories that largely fall within limits observed in the real system. Moreover, the model demonstrates behaviors that have relevance for management considerations. In particular, differences in larval supply between reef localities drive spatial variability in modeled reef community structure. Reef tracts for which recruitment is low are more vulnerable to natural disturbance and synergistic effects of anthropogenic stressors. Our approach provides a framework for projecting the likelihood of different reef futures at local to regional scales, with important applications for the management of complex coral reef systems.

  1. Correction tool for Active Shape Model based lumbar muscle segmentation.

    Science.gov (United States)

    Valenzuela, Waldo; Ferguson, Stephen J; Ignasiak, Dominika; Diserens, Gaelle; Vermathen, Peter; Boesch, Chris; Reyes, Mauricio

    2015-08-01

    In the clinical environment, accuracy and speed of the image segmentation process plays a key role in the analysis of pathological regions. Despite advances in anatomic image segmentation, time-effective correction tools are commonly needed to improve segmentation results. Therefore, these tools must provide faster corrections with a low number of interactions, and a user-independent solution. In this work we present a new interactive correction method for correcting the image segmentation. Given an initial segmentation and the original image, our tool provides a 2D/3D environment, that enables 3D shape correction through simple 2D interactions. Our scheme is based on direct manipulation of free form deformation adapted to a 2D environment. This approach enables an intuitive and natural correction of 3D segmentation results. The developed method has been implemented into a software tool and has been evaluated for the task of lumbar muscle segmentation from Magnetic Resonance Images. Experimental results show that full segmentation correction could be performed within an average correction time of 6±4 minutes and an average of 68±37 number of interactions, while maintaining the quality of the final segmentation result within an average Dice coefficient of 0.92±0.03.

  2. Using urban forest assessment tools to model bird habitat potential

    Science.gov (United States)

    Susannah B. Lerman; Keith H. Nislow; David J. Nowak; Stephen DeStefano; David I. King; D. Todd. Jones-Farrand

    2014-01-01

    The alteration of forest cover and the replacement of native vegetation with buildings, roads, exotic vegetation, and other urban features pose one of the greatest threats to global biodiversity. As more land becomes slated for urban development, identifying effective urban forest wildlife management tools becomes paramount to ensure the urban forest provides habitat...

  3. An Energy Systems Modelling Tool for the Social Simulation Community

    NARCIS (Netherlands)

    Bollinger, L. Andrew; van Blijswijk, Martti J.; Dijkema, Gerard P.J.; Nikolic, Igor

    2016-01-01

    The growing importance of links between the social and technical dimensions of the electricity infrastructure mean that many research problems cannot be effectively addressed without joint consideration of social and technical dynamics. This paper motivates the need for and introduces a tool to

  4. Advanced Computing Tools and Models for Accelerator Physics

    Energy Technology Data Exchange (ETDEWEB)

    Ryne, Robert; Ryne, Robert D.

    2008-06-11

    This paper is based on a transcript of my EPAC'08 presentation on advanced computing tools for accelerator physics. Following an introduction I present several examples, provide a history of the development of beam dynamics capabilities, and conclude with thoughts on the future of large scale computing in accelerator physics.

  5. UASB reactor hydrodynamics: residence time distribution and proposed modelling tools.

    Science.gov (United States)

    López, I; Borzacconi, L

    2010-05-01

    The hydrodynamic behaviour of UASB (Up Flow Anaerobic Sludge Blanket) reactors based on residence time distribution curves allows the implementation of global models, including the kinetic aspects of biological reactions. The most relevant hydrodynamic models proposed in the literature are discussed and compared with the extended tanks in series (ETIS) model. Although derived from the tanks in series model, the ETIS model's parameter is not an integer. The ETIS model can be easily solved in the Laplace domain and applied to a two-stage anaerobic digestion linear model. Experimental data from a 250 m3 UASB reactor treating malting wastewater are used to calibrate and validate the proposed model.

  6. MQ-2 A Tool for Prolog-based Model Querying

    DEFF Research Database (Denmark)

    Acretoaie, Vlad; Störrle, Harald

    2012-01-01

    MQ-2 integrates a Prolog console into the MagicDraw1 modeling environment and equips this console with features targeted specifically to the task of querying models. The vision of MQ-2 is to make Prolog-based model querying accessible to both student and expert modelers by offering powerful query...

  7. Teachers' Use of Computational Tools to Construct and Explore Dynamic Mathematical Models

    Science.gov (United States)

    Santos-Trigo, Manuel; Reyes-Rodriguez, Aaron

    2011-01-01

    To what extent does the use of computational tools offer teachers the possibility of constructing dynamic models to identify and explore diverse mathematical relations? What ways of reasoning or thinking about the problems emerge during the model construction process that involves the use of the tools? These research questions guided the…

  8. Evaluating the Usability of a Professional Modeling Tool Repurposed for Middle School Learning

    Science.gov (United States)

    Peters, Vanessa L.; Songer, Nancy Butler

    2013-01-01

    This paper reports the results of a three-stage usability test of a modeling tool designed to support learners' deep understanding of the impacts of climate change on ecosystems. The design process involved repurposing an existing modeling technology used by professional scientists into a learning tool specifically designed for middle school…

  9. Customer Data Analysis Model using Business Intelligence Tools in Telecommunication Companies

    Directory of Open Access Journals (Sweden)

    Monica LIA

    2015-10-01

    Full Text Available This article presents a customer data analysis model in a telecommunication company and business intelligence tools for data modelling, transforming, data visualization and dynamic reports building . For a mature market, knowing the information inside the data and making forecast for strategic decision become more important in Romanian Market. Business Intelligence tools are used in business organization as support for decision making.

  10. A Decision Support Model and Tool to Assist Financial Decision-Making in Universities

    Science.gov (United States)

    Bhayat, Imtiaz; Manuguerra, Maurizio; Baldock, Clive

    2015-01-01

    In this paper, a model and tool is proposed to assist universities and other mission-based organisations to ascertain systematically the optimal portfolio of projects, in any year, meeting the organisations risk tolerances and available funds. The model and tool presented build on previous work on university operations and decision support systems…

  11. Port performance evaluation tool based on microsimulation model

    OpenAIRE

    Tsavalista Burhani Jzolanda; Zukhruf Febri; Bona Frazila Russ

    2017-01-01

    As port performance is becoming correlative to national competitiveness, the issue of port performance evaluation has significantly raised. Port performances can simply be indicated by port service levels to the ship (e.g., throughput, waiting for berthing etc.), as well as the utilization level of equipment and facilities within a certain period. The performances evaluation then can be used as a tool to develop related policies for improving the port’s performance to be more effective and ef...

  12. Solid-state-drives (SSDs) modeling simulation tools & strategies

    CERN Document Server

    2017-01-01

    This book introduces simulation tools and strategies for complex systems of solid-state-drives (SSDs) which consist of a flash multi-core microcontroller plus NAND flash memories. It provides a broad overview of the most popular simulation tools, with special focus on open source solutions. VSSIM, NANDFlashSim and DiskSim are benchmarked against performances of real SSDs under different traffic workloads. PROs and CONs of each simulator are analyzed, and it is clearly indicated which kind of answers each of them can give and at a what price. It is explained, that speed and precision do not go hand in hand, and it is important to understand when to simulate what, and with which tool. Being able to simulate SSD’s performances is mandatory to meet time-to-market, together with product cost and quality. Over the last few years the authors developed an advanced simulator named “SSDExplorer” which has been used to evaluate multiple phenomena with great accuracy, from QoS (Quality Of Service) to Read Retry, fr...

  13. Tools and data for the geochemical modeling. Thermodynamic data for sulfur species and background salts and tools for the uncertainty analysis; WEDA. Werkzeuge und Daten fuer die Geochemische Modellierung. Thermodynamische Daten fuer Schwefelspezies und Hintergrundsalze sowie Tools zur Unsicherheitsanalyse

    Energy Technology Data Exchange (ETDEWEB)

    Hagemann, Sven; Schoenwiese, Dagmar; Scharge, Tina

    2015-07-15

    The report on tools and data for the geochemical modeling covers the following issues: experimental methods and theoretical models, design of a thermodynamic model for reduced sulfur species, thermodynamic models for background salts, tools for the uncertainty and sensitivity analyses of geochemical equilibrium modeling.

  14. The Quantum Atomic Model "Electronium": A Successful Teaching Tool.

    Science.gov (United States)

    Budde, Marion; Niedderer, Hans; Scott, Philip; Leach, John

    2002-01-01

    Focuses on the quantum atomic model Electronium. Outlines the Bremen teaching approach in which this model is used, and analyzes the learning of two students as they progress through the teaching unit. (Author/MM)

  15. Parameter Extraction for PSpice Models by means of an Automated Optimization Tool – An IGBT model Study Case

    DEFF Research Database (Denmark)

    Suárez, Carlos Gómez; Reigosa, Paula Diaz; Iannuzzo, Francesco

    2016-01-01

    An original tool for parameter extraction of PSpice models has been released, enabling a simple parameter identification. A physics-based IGBT model is used to demonstrate that the optimization tool is capable of generating a set of parameters which predicts the steady-state and switching behavior...

  16. The Role of Explicit and Implicit Self-Esteem in Peer Modeling of Palatable Food Intake: A Study on Social Media Interaction among Youngsters

    National Research Council Canada - National Science Library

    Bevelander, K.E; Anschutz, D.J; Creemers, D.H.M; Kleinjan, M; Engels, R.C.M.E

    2013-01-01

    ... (i.e., instructed peer) who ate either nothing, a small or large amount of candy. Results: Participants modeled the candy intake of peers via a social media interaction, but this was qualified by their self-esteem...

  17. Process models as tools in forestry research and management

    Science.gov (United States)

    Kurt Johnsen; Lisa Samuelson; Robert Teskey; Steve McNulty; Tom Fox

    2001-01-01

    Forest process models are mathematical representations of biological systems that incorporate our understanding of physiological and ecological mechanisms into predictive algorithms. These models were originally designed and used for research purposes, but are being developed for use in practical forest management. Process models designed for research...

  18. A review of a method for dynamic load distribution, dynamic modeling, and explicit internal force control when two serial link manipulators mutually lift and transport a rigid body object

    Energy Technology Data Exchange (ETDEWEB)

    Unseren, M.A.

    1997-09-01

    The report reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restricts the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system.

  19. Towards Semantically Integrated Models and Tools for Cyber-Physical Systems Design

    DEFF Research Database (Denmark)

    Larsen, Peter Gorm; Fitzgerald, John; Woodcock, Jim

    2016-01-01

    modelling. Learning from experience with binary co-modelling based on a bespoke operational semantics, we describe current work delivering an extended approach that enables integration of multiple models and tools in a consistent tool chain, founded on an extensible semantic framework exploiting......We describe an approach to the model-based engineering of embedded and cyber-physical systems, based on the semantic integration of diverse discipline-specific notations and tools. Using the example of a small unmanned aerial vehicle, we explain the need for multiple notations and collaborative...

  20. Modeling Hospital Information Systems (Part 2): using the 3LGM2 tool for modeling patient record management.

    Science.gov (United States)

    Wendt, T; Häber, A; Brigl, B; Winter, A

    2004-01-01

    We introduce the 3LGM(2) tool, a tool for modeling information systems, and describe the process of modeling parts of the hospital information system of the Leipzig University Hospital (UKL(a)). We modeled the sub information systems of five patient record archiving sections to support the creation of a proposal for governmental financial support for a new document management and archiving system. We explain the steps of identifying the model elements and their relations as well as the analyzing capabilities of the 3LGM(2) tool to answer questions about the information system. The 3LGM(2) tool was developed on the basis of the meta model 3LGM(2) which is described in detail in [1]. 3LGM(2) defines an ontological basis, divided into three layers and their relationships. In addition to usual meta CASE tools, the 3LGM(2) tool meets certain requirements of information management in hospitals. The model described in this article was created on the base of on-site surveys in five archiving sections of the UKL. A prototype of the 3LGM(2) tool is available and is currently tested in some projects at the UKL and partner institutions. The model presented in this article is a structured documentation about the current state of patient record archiving at the UKL. The analyzing capabilities of the 3LGM(2) tool help to use the model and to answer questions about the information system. The 3LGM(2) tool can be used to model and analyze information systems. The presentation capabilities and the reliability of the prototype have to be improved. The initial modeling effort of an institution is only valuable if the model is maintained regularly and reused in other projects. Reference catalogues and reference models are needed to decrease this effort and to support the creation of comparable models.

  1. CFD model of multiphase flow in the abrasive water jet tool

    OpenAIRE

    Říha, Zdeněk

    2015-01-01

    The possibility of using CFD fluid flow modeling in area of tools with abrasive water jet is described in the paper. The correct function of such tool is based on proper setting of multiphase flow of water, air and solid particles in the inner space of the tool. The multiphase fluid flow numerical simulation can provide information which show relation between the geometry and the flow field. Then, this stable CFD model of multiphase flow creates key to design of the tool able to work wi...

  2. DiVinE-CUDA - A Tool for GPU Accelerated LTL Model Checking

    Directory of Open Access Journals (Sweden)

    Jiří Barnat

    2009-12-01

    Full Text Available In this paper we present a tool that performs CUDA accelerated LTL Model Checking. The tool exploits parallel algorithm MAP adjusted to the NVIDIA CUDA architecture in order to efficiently detect the presence of accepting cycles in a directed graph. Accepting cycle detection is the core algorithmic procedure in automata-based LTL Model Checking. We demonstrate that the tool outperforms non-accelerated version of the algorithm and we discuss where the limits of the tool are and what we intend to do in the future to avoid them.

  3. Entropy of biogeochemical compartment models: complexity and information content as a tool for model development

    Science.gov (United States)

    Metzler, Holger; Sierra, Carlos A.

    2017-04-01

    Most soil organic matter decomposition models consist of a number of compartments describing the dynamics of substrate and microbial biomass pools. The fluxes of mass between the compartments are usually described by a system of ordinary differential equations, in which the number of compartments and the connections among them define the complexity of the model and the number of biological processes that need to be described. With this approach, it is difficult to determine the level of detail that is required to describe a given system, and it is also difficult to compare models against each other due to large differences in their level of complexity. Here, we propose entropy as a tool to determine the level of complexity required to describe a biogeochemical system and to compare the information content of different models. Instead of entire masses on bulk soil level, we look at such models from the point of view of a single particle on the molecular level. This particle enters the system, cycles through it, and leaves it at some point later in time, thereby following a path through the system. We think of this path as a particular stochastic process, a Markov renewal process. If we consider this path as a random variable in a path space, its Shannon information entropy describes its information content, i.e. how much we learn when we observe the entire path of a particle traveling through the system. In other words, it tells us how hard it is to predict this path and thus how much we do not know about what is going to happen to one single particle. The entropy as a measure of model complexity can help us to decide whether a model is not complex enough to represent the information that we have about a system or whether it is too complex. The concept of maximum entropy provides a powerful tool to develop unbiased models, i.e. models that contain the exact amount of information that we have about the system. In addition, differences between a soil organic matter

  4. WeedML: a Tool for Collaborative Weed Demographic Modeling

    OpenAIRE

    Holst, Niels

    2010-01-01

    WeedML is a proposed standard to formulate models of weed demography, or maybe even complex models in general, that are both transparent and straightforward to re-use as building blocks for new models. The paper describes the design and thoughts behind WeedML which relies on XML and object-oriented systems development. Proof-of-concept software is provided as open-source C++ code and executables that can be downloaded freely.

  5. Energy life-cycle analysis modeling and decision support tool

    Energy Technology Data Exchange (ETDEWEB)

    Hoza, M.; White, M.E.

    1993-06-01

    As one of DOE`s five multi-program national laboratories, Pacific Northwest Laboratory (PNL) develops and deploys technology for national missions in energy and the environment. The Energy Information Systems Group, within the Laboratory`s Computer Sciences Department, focuses on the development of the computational and data communications infrastructure and automated tools for the Transmission and Distribution energy sector and for advanced process engineering applications. The energy industry is being forced to operate in new ways and under new constraints. It is in a reactive mode, reacting to policies and politics, and to economics and environmental pressures. The transmission and distribution sectors are being forced to find new ways to maximize the use of their existing infrastructure, increase energy efficiency, and minimize environmental impacts, while continuing to meet the demands of an ever increasing population. The creation of a sustainable energy future will be a challenge for both the soft and hard sciences. It will require that we as creators of our future be bold in the way we think about our energy future and aggressive in its development. The development of tools to help bring about a sustainable future will not be simple either. The development of ELCAM, for example, represents a stretch for the computational sciences as well as for each of the domain sciences such as economics, which will have to be team members.

  6. The effect of area size and predation on the time to extinction of prairie vole populations. simulation studies via SERDYCA: a Spatially-Explicit Individual-Based Model of Rodent Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Kostova, T; Carlsen, T

    2003-11-21

    We present a spatially-explicit individual-based computational model of rodent dynamics, customized for the prairie vole species, M. Ochrogaster. The model is based on trophic relationships and represents important features such as territorial competition, mating behavior, density-dependent predation and dispersal out of the modeled spatial region. Vegetation growth and vole fecundity are dependent on climatic components. The results of simulations show that the model correctly predicts the overall temporal dynamics of the population density. Time-series analysis shows a very good match between the periods corresponding to the peak population density frequencies predicted by the model and the ones reported in the literature. The model is used to study the relation between persistence, landscape area and predation. We introduce the notions of average time to extinction (ATE) and persistence frequency to quantify persistence. While the ATE decreases with decrease of area, it is a bell-shaped function of the predation level: increasing for 'small' and decreasing for 'large' predation levels.

  7. Parallel Explicit and Implicit Control of Reaching

    OpenAIRE

    Pietro Mazzoni; Wexler, Nancy S

    2009-01-01

    Background Human movement can be guided automatically (implicit control) or attentively (explicit control). Explicit control may be engaged when learning a new movement, while implicit control enables simultaneous execution of multiple actions. Explicit and implicit control can often be assigned arbitrarily: we can simultaneously drive a car and tune the radio, seamlessly allocating implicit or explicit control to either action. This flexibility suggests that sensorimotor signals, including t...

  8. Modelling deep water habitats to develop a spatially explicit, fine scale understanding of the distribution of the western rock lobster, Panulirus cygnus.

    Directory of Open Access Journals (Sweden)

    Renae K Hovey

    Full Text Available BACKGROUND: The western rock lobster, Panulirus cygnus, is endemic to Western Australia and supports substantial commercial and recreational fisheries. Due to and its wide distribution and the commercial and recreational importance of the species a key component of managing western rock lobster is understanding the ecological processes and interactions that may influence lobster abundance and distribution. Using terrain analyses and distribution models of substrate and benthic biota, we assess the physical drivers that influence the distribution of lobsters at a key fishery site. METHODS AND FINDINGS: Using data collected from hydroacoustic and towed video surveys, 20 variables (including geophysical, substrate and biota variables were developed to predict the distributions of substrate type (three classes of reef, rhodoliths and sand and dominant biota (kelp, sessile invertebrates and macroalgae within a 40 km(2 area about 30 km off the west Australian coast. Lobster presence/absence data were collected within this area using georeferenced pots. These datasets were used to develop a classification tree model for predicting the distribution of the western rock lobster. Interestingly, kelp and reef were not selected as predictors. Instead, the model selected geophysical and geomorphic scalar variables, which emphasise a mix of terrain within limited distances. The model of lobster presence had an adjusted D(2 of 64 and an 80% correct classification. CONCLUSIONS: Species distribution models indicate that juxtaposition in fine scale terrain is most important to the western rock lobster. While key features like kelp and reef may be important to lobster distribution at a broad scale, it is the fine scale features in terrain that are likely to define its ecological niche. Determining the most appropriate landscape configuration and scale will be essential to refining niche habitats and will aid in selecting appropriate sites for protecting critical

  9. Modelling deep water habitats to develop a spatially explicit, fine scale understanding of the distribution of the western rock lobster, Panulirus cygnus.

    Science.gov (United States)

    Hovey, Renae K; Van Niel, Kimberly P; Bellchambers, Lynda M; Pember, Matthew B

    2012-01-01

    The western rock lobster, Panulirus cygnus, is endemic to Western Australia and supports substantial commercial and recreational fisheries. Due to and its wide distribution and the commercial and recreational importance of the species a key component of managing western rock lobster is understanding the ecological processes and interactions that may influence lobster abundance and distribution. Using terrain analyses and distribution models of substrate and benthic biota, we assess the physical drivers that influence the distribution of lobsters at a key fishery site. Using data collected from hydroacoustic and towed video surveys, 20 variables (including geophysical, substrate and biota variables) were developed to predict the distributions of substrate type (three classes of reef, rhodoliths and sand) and dominant biota (kelp, sessile invertebrates and macroalgae) within a 40 km(2) area about 30 km off the west Australian coast. Lobster presence/absence data were collected within this area using georeferenced pots. These datasets were used to develop a classification tree model for predicting the distribution of the western rock lobster. Interestingly, kelp and reef were not selected as predictors. Instead, the model selected geophysical and geomorphic scalar variables, which emphasise a mix of terrain within limited distances. The model of lobster presence had an adjusted D(2) of 64 and an 80% correct classification. Species distribution models indicate that juxtaposition in fine scale terrain is most important to the western rock lobster. While key features like kelp and reef may be important to lobster distribution at a broad scale, it is the fine scale features in terrain that are likely to define its ecological niche. Determining the most appropriate landscape configuration and scale will be essential to refining niche habitats and will aid in selecting appropriate sites for protecting critical lobster habitats.

  10. AIR Model: A Teaching Tool for Cultivating Reflective Ethical Inquiry

    Science.gov (United States)

    Cohen, Perrin; McDaniels, Melissa; Qualters, Donna M.

    2005-01-01

    The AIR model we describe in this article is a practical framework for cultivating reflective inquiry into ethical issues that students, faculty, and administrators experience in the midst of busy daily lives and encounter in classroom discussions in a discipline field. The model is highly adaptable to academic and workplace settings and enables…

  11. Requirements Validation: Execution of UML Models with CPN Tools

    DEFF Research Database (Denmark)

    Machado, Ricardo J.; Lassen, Kristian Bisgaard; Oliveira, Sérgio

    2007-01-01

    with simple unified modelling language (UML) requirements models, it is not easy for the development team to get confidence on the stakeholders' requirements validation. This paper describes an approach, based on the construction of executable interactive prototypes, to support the validation of workflow...

  12. Molecular Modeling: A Powerful Tool for Drug Design and Molecular ...

    Indian Academy of Sciences (India)

    gating, interpreting, explaining and discovering new phenom- ena. Like experimental chemistry, it is a skill-demanding sci- ence and must be learnt by doing and not just reading. Molecular modeling is easy to perform with currently available software, but the difficulty lies in getting the right model and proper interpretation.

  13. [Study of dental model testing tool based on robot theory].

    Science.gov (United States)

    Hu, B; Song, Y; Cheng, L

    1999-09-01

    A new three dimensional testing and analysing system of dental model is discussed It is designed based on the motion theory of robots. The system is capable of not only measuring the three dimensional sizes of dental models, but also saving and outputing the tested data. The construction of the system is briefly introduced here.

  14. An integrated user-friendly ArcMAP tool for bivariate statistical modeling in geoscience applications

    Science.gov (United States)

    Jebur, M. N.; Pradhan, B.; Shafri, H. Z. M.; Yusof, Z.; Tehrany, M. S.

    2014-10-01

    Modeling and classification difficulties are fundamental issues in natural hazard assessment. A geographic information system (GIS) is a domain that requires users to use various tools to perform different types of spatial modeling. Bivariate statistical analysis (BSA) assists in hazard modeling. To perform this analysis, several calculations are required and the user has to transfer data from one format to another. Most researchers perform these calculations manually by using Microsoft Excel or other programs. This process is time consuming and carries a degree of uncertainty. The lack of proper tools to implement BSA in a GIS environment prompted this study. In this paper, a user-friendly tool, BSM (bivariate statistical modeler), for BSA technique is proposed. Three popular BSA techniques such as frequency ratio, weights-of-evidence, and evidential belief function models are applied in the newly proposed ArcMAP tool. This tool is programmed in Python and is created by a simple graphical user interface, which facilitates the improvement of model performance. The proposed tool implements BSA automatically, thus allowing numerous variables to be examined. To validate the capability and accuracy of this program, a pilot test area in Malaysia is selected and all three models are tested by using the proposed program. Area under curve is used to measure the success rate and prediction rate. Results demonstrate that the proposed program executes BSA with reasonable accuracy. The proposed BSA tool can be used in numerous applications, such as natural hazard, mineral potential, hydrological, and other engineering and environmental applications.

  15. Tool Support for Collaborative Teaching and Learning of Object-Oriented Modelling

    DEFF Research Database (Denmark)

    Hansen, Klaus Marius; Ratzer, Anne Vinter

    2002-01-01

    Modeling is central to doing and learning object-oriented development. We present a new tool, Ideogramic UML, for gesture-based collaborative modeling with the Unified Modeling Language (UML), which can be used to collaboratively teach and learn modeling. Furthermore, we discuss how we have...

  16. Explicit Finite-Difference Scheme for the Numerical Solution of the Model Equation of Nonlinear Hereditary Oscillator with Variable-Order Fractional Derivatives

    Directory of Open Access Journals (Sweden)

    Parovik Roman I.

    2016-09-01

    Full Text Available The paper deals with the model of variable-order nonlinear hereditary oscillator based on a numerical finite-difference scheme. Numerical experiments have been carried out to evaluate the stability and convergence of the difference scheme. It is argued that the approximation, stability and convergence are of the first order, while the scheme is stable and converges to the exact solution.

  17. General Equilibrium in a Nutshell: An Explicit Function Example.

    Science.gov (United States)

    Yunker, James A.

    1998-01-01

    Describes a general equilibrium model that fills the gap between the general function models described in price-theory textbooks and the numerical practice of general equilibrium analysis used in contemporary policy assessment. This model uses explicit mathematical forms but general parameter values. Includes graphs and statistical tables. (MJP)

  18. MODELING COMPARATIVE THERMAL PERFORMANCE OF LIGHTWEIGHT FABRICS USING A COMPUTATIONAL DESIGN TOOL

    Science.gov (United States)

    2017-04-14

    M., Bieszczad, J., Gagne, J., Fogg, D., Fan, J., “ Design Tool for Clothing Applications: Wind Resistant Fabric Layers and Permeable Vents,” Journal ...THERMAL PERFORMANCE OF LIGHTWEIGHT FABRICS USING A COMPUTATIONAL DESIGN TOOL by Judith Sennett and Phillip Gibson April 2017...MODELING COMPARATIVE THERMAL PERFORMANCE OF LIGHTWEIGHT FABRICS USING A COMPUTATIONAL DESIGN TOOL 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  19. Towards diagnostic tools for analysing Swarm data through model retrievals

    DEFF Research Database (Denmark)

    Kotsiaros, Stavros; Plank, Gernot; Haagmans, R.

    polar orbits between 300 and 550 km altitude. Goal of the current study is to build tools and to analyze datasets, in order to allow a fast diagnosis of the Swarm system performance in orbit during the commission phase and operations of the spacecraft. The effects on the reconstruction of the magnetic......, position errors and data gaps. The magnitude of the different error sources is kept variable so that we not only compare the impact of different error sources, but investigate also the effects on the magnetic field reconstruction for different noise levels. Further extension of this approach will allow...... to test the influence of ionospheric residual signal or the impact of data selection on the lithospheric retrieval. Initially, the study considers one satellite and emphasises on the lithospheric field reconstruction, but in a second step it is extended to a realistic Swarm constellation of three...

  20. Geodynamo models: Tools for understanding properties of Earth's magnetic field

    Science.gov (United States)

    Christensen, Ulrich R.

    2011-08-01

    Self-consistent models of the dynamo process in the Earth's core have reached a state where they can be used to understand specific morphological and temporal properties of the geomagnetic field. Even though several parameters in the models are far from Earth values, systematic parameter studies resulted in scaling laws that suggest that the dynamical regime in the models is not dissimilar to that in the core