These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

SPY: A new scission point model based on microscopic ingredients to predict fission fragments properties  

NASA Astrophysics Data System (ADS)

Our purpose is to determine fission fragments characteristics in a framework of a scission point model named SPY for Scission Point Yields. This approach can be considered as a theoretical laboratory to study fission mechanism since it gives access to the correlation between the fragments properties and their nuclear structure, such as shell correction, pairing, collective degrees of freedom, odd-even effects. Which ones are dominant in final state? What is the impact of compound nucleus structure? The SPY model consists in a statistical description of the fission process at the scission point where fragments are completely formed and well separated with fixed properties. The most important property of the model relies on the nuclear structure of the fragments which is derived from full quantum microscopic calculations. This approach allows computing the fission final state of extremely exotic nuclei which are inaccessible by most of the fission model available on the market.

Lemaître, J.-F.; Dubray, N.; Hilaire, S.; Panebianco, S.; Sida, J.-L.

2013-12-01

2

The Scission-Point Configuration within the Two-Center Shell Model Shape Parameterization  

E-print Network

Within the two-center shell model parameterization we have defined the optimal shape which fissioning nuclei attain just before the scission and calculated the total deformation energy (liquid drop part plus the shell correction) as function of the mass asymmetry and elongation at the scission point. The three minima corresponding to mass symmetric and two mass asymmetric peaks in the mass distribution of fission fragments are found in the deformation energy at the scission point. The calculated deformation energy is used in quasi-static approximation for the estimation of the total kinetic and excitation energy of fission fragments and the total number of emitted prompt neutrons. The calculated results reproduce rather well the experimental data on the position of the peaks in the mass distribution of fission fragments, the total kinetic and excitation energy of fission fragments. The calculated value of neutron multiplicity is somewhat larger than experimental results.

F. A. Ivanyuk; S. Chiba; Y. Aritomo

2014-10-28

3

Scission-point configuration within the two-center shell model shape parameterization  

NASA Astrophysics Data System (ADS)

Within the two-center shell model parameterization we defined the optimal shape that fissioning nuclei attain just before the scission and calculated the total deformation energy (liquid-drop part plus the shell correction) as a function of the mass asymmetry and elongation at the scission point. The three minima corresponding to one mass-symmetric and two mass-asymmetric peaks in the mass distribution of fission fragments are found in the deformation energy at the scission point. The calculated deformation energy is used in a quasistatic approximation for the estimation of the total kinetic and excitation energies of fission fragments and the total number of emitted prompt neutrons. The calculated results reproduce rather well the experimental data on the position of the peaks in the mass distribution of fission fragments, and the total kinetic and excitation energies of fission fragments. The calculated value of neutron multiplicity is somewhat larger than experimental results.

Ivanyuk, F. A.; Chiba, S.; Aritomo, Y.

2014-11-01

4

The shell effects in the scission-point configuration of fissioning nuclei  

NASA Astrophysics Data System (ADS)

In the present work the formal definition of the scission point—the maximal elongation at which the nucleus splits into two fragments—is given. The shape and the deformation energy at the scission point are calculated using the macroscopic-microscopic model. Three minima in the scission point deformation energy are found corresponding to the ‘standard’, ‘supershort’ and ‘superlong’ fission modes. The contribution of each fission mode to the mass distribution of the fission fragments and total kinetic energy is discussed and compared with the experimental results. In the example of the fission of U-235 by thermal neutrons it is shown that the present approach reproduces correctly the position of the peaks of the mass distribution of the fission fragments, the value and the fine details of the total kinetic energy distribution and the magnitude of the total excitation energy of the fission fragments.

Ivanyuk, F. A.

2014-05-01

5

Binary and Ternary Fission Within the Statistical Model  

Microsoft Academic Search

The binary and ternary nuclear fission are treated within the statistical model. At the scission point we calculate the potentials as functions of the deformations of the fragments in the dinuclear model. The potentials give the mass and charge distributions of the fission fragments. The ternary fission is assumed to occur during the binary fission.

Gurgen G. Adamian; Alexander V. Andreev; Nikolai V. Antonenko; Werner Scheid

2008-01-01

6

Clustering Effects Within the Dinuclear Model  

NASA Astrophysics Data System (ADS)

The clustering of two nuclei in a nuclear system creates configurations denoted in literature as nuclear molecular structures. A nuclear molecule or a dinuclear system (DNS) as named by Volkov consists of two touching nuclei (clusters) which keep their individuality. Such a system has two main degrees of freedom of collective motions which govern its dynamics: (i) the relative motion between the clusters leading to molecular resonances in the internuclear potential and to the decay of the dinuclear system (separation of the clusters) which is called quasifission since no compound system like in fission is first formed. (ii) the transfer of nucleons or light constituents between the two clusters of the dinuclear system leading to a special dynamics of the mass and charge asymmetries between the clusters in fusion and fission reactions. In this article we discuss the essential aspects of the diabatic internuclear potential used by the di-nuclear system concept and present applications to nuclear structure and reactions. We show applications of the dinuclear model to superdeformed and hyperdeformed bands. An extended discussion is given to the problems of fusion dynamics in the production of superheavy nuclei, to the quasifission process and to multi-nucleon transfer between nuclei. Also the binary and ternary fission processes are discussed within the scission-point model and the dinuclear system concept.

Adamian, Gurgen; Antonenko, Nikolai; Scheid, Werner

7

Modelling  

E-print Network

Modeling of technical machines became a standard technique since computer became powerful enough to handle the amount of data relevant to the specific system. Simulation of an existing physical device requires the knowledge of all relevant quantities. Electric fields given by the surrounding boundary as well as magnetic fields caused by coils or permanent magnets have to be known. Internal sources for both fields are sometimes taken into account, such as space charge forces or the internal magnetic field of a moving bunch of charged particles. Used solver routines are briefly described and some bench-marking is shown to estimate necessary computing times for different problems. Different types of charged particle sources will be shown together with a suitable model to describe the physical model. Electron guns are covered as well as different ion sources (volume ion sources, laser ion sources, Penning ion sources, electron resonance ion sources, and H$^-$-sources) together with some remarks on beam transport.

Spädtke, P

2013-01-01

8

Modeling  

NASA Technical Reports Server (NTRS)

A prediction of the future population of satellites, satellite fragments, and assorted spacecraft debris in Earth orbit can be reliably made only after three conditions are satisfied: (1) the size and spatial distributions of these Earth-orbiting objects are established at some present-day time; (2) the processes of orbital evolution, explosions, hypervelocity impact fragmentation, and atmospheric drag are understood; and (3) a reasonable traffic model for the future launch rate of Earth-orbiting objects is assumed. The theoretician will then take these three quantities as input data and will carry through the necessary mathematica and numerical analyses to project the present-day orbital population into the future.

Zook, H. A.

1985-01-01

9

Modeling modeling.  

PubMed Central

Models are tools; they need to fit both the hand and the task. Presence or absence of a feature such as a pacemaker or a cascade is not in itself good. Or bad. Criteria for model evaluation involve benefit-cost ratios, with the numerator a function of the range of phenomena explained, goodness of fit, consistency with other nearby models, and intangibles such as beauty. The denominator is a function of complexity, the number of phenomena that must be ignored, and the effort necessary to incorporate the model into one's parlance. Neither part of the ratio can yet be evaluated for MTS, whose authors provide some cogent challenges to SET. PMID:10220934

Killeen, P R

1999-01-01

10

Collective spectra along the fission barrier  

NASA Astrophysics Data System (ADS)

Discrete and continuous spectra of fissioning nuclei at the humps of fission barriers (Bohr transition states) and in the intermediate wells (superdeformed and hyperdeformed states) play a key role in the calculation of fission cross sections. A theoretical evaluation of the collective parts of the spectra is possible within the framework of the dinuclear system model, which treats the wave function of the fissioning nucleus as a superposition of a mononucleus configuration and two-cluster configurations in a dynamical way, permitting exchange of upper-shell nucleons between clusters. The impact of theoretical spectra on neutron-induced fission cross sections and, in combination with an improved version of the scission-point model, on angular distribution of fission fragments is evaluated for plutonium isotopes of interest to nuclear energy applications.

Shneidman, T. M.; Andreev, A. V.; Pigni, M. T.; Massimi, C.; Vannini, G.; Ventura, A.

2012-12-01

11

Analysis of Fragment Mass Distribution in Asymmetric Area at Fission of {sup 235}U Induced by Thermal Neutrons  

SciTech Connect

The fragment mass yields in fission of {sup 235}U induced by thermal neutrons for A=145 - 160 and E{sub K}=50 - 75 MeV were measured using a mass spectrometer. The fine structure is observed at A=153, 154 and E{sub K}=50 - 60 MeV. The obtained results were described in the framework of a model based on the dinuclear system concept. The analyzed correlation between the total kinetic energy and mass distribution of fission fragments is connected with the shell structure of the formed fragments of fission. From this correlation and the time dependence of the calculated mass distribution of the binary reaction products, one can conclude that the descent time from a saddle point to a scission point for the more deformed fragments is longer than that for fragments of more compact shape.

Pikul, V.P.; Koblik, Yu.N.; Khugaev, A.V.; Yuldashev, B.S. [Institute of Nuclear Physics, Tashkent (Uzbekistan); Jovliev, U.Yu.; Muminov, A.I.; Pavliy, K.V. [Heavy-Ion Physics Department, Institute of Nuclear Physics, Tashkent (Uzbekistan); Nasirov, A.K. [Heavy-Ion Physics Department, Institute of Nuclear Physics, Tashkent (Uzbekistan); Bogolyubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow oblast, 141980 (Russian Federation)

2005-02-01

12

Effects of nuclear deformation in dinuclear systems: Application to the fission process  

SciTech Connect

The relative yields of fission fragments, the mean values of their total kinetic energy, and the variances of their distributions with respect to the total kinetic energy are described within the improved scission-point model. It is shown that, for fixed charge and mass numbers of fragments, the potential energy of the precision configuration as a function of the deformation parameters of the fragments has several minima. The scission at these minima leads to a relative enhancement of the yields of the fragments that have the corresponding values of the total kinetic energy and to the appearance of a fine structure in the mass-energy distribution, this structure being different from that induced by the even-odd effect.

Andreev, A. V.; Adamian, G. G.; Antonenko, N. V.; Ivanova, S. P. [Joint Institute for Nuclear Research (Russian Federation)], E-mail: Ivanova@uc.jinr.ru; Scheid, W. [Justus-Liebig-Universitaet (Germany)

2006-02-15

13

Collective modes associated with the proton-induced fission of /sup 209/Bi  

SciTech Connect

Gamma-ray multiplicity (first and second moments) has been measured in the 60 MeV proton induced fission of /sup 209/Bi. From this work we have evidences that shell effects play an effective role at the scission point, even at an excitation energy of 65 MeV. Collective modes seem to be more easily excited when the nascent fragments are far from spherical shapes. The ..gamma..-multiplicity moments seem to depend weakly on excitation energy of the fissioning nucleus and do not reflect really the angular momentum of the entrance channel. The good agreement of our results with Moretto-Schmitt model supports highly the role played by collective modes (bending) in the heavy ion induced fission and deep inelastic collisions which are presently the field of many recent experimental and theoretical investigations.

Nowicki, L.; Berlanger, M.; Borderie, B.; Cabot, C.; del, P. Marmol; El, Y. Masri; Gregoire, C.; Hanappe, F.; Ngo, C.; Tamain, B.

1982-09-01

14

NUCLEAR MODELS  

Microsoft Academic Search

As an introduction to the discussion of nuclear models, the Bohr atomic ; model is described. The nuclear model analogous to this atomic model is then ; discussed. Because of the very narrow nuclear levels found by Fermi, the ; compound nucleus model was then proposed. This model was limited in the region ; of very high and very low

Beck

1956-01-01

15

MODEL DEVELOPMENT - DOSE MODELS  

EPA Science Inventory

Model Development Humans are exposed to mixtures of chemicals from multiple pathways and routes. These exposures may result from a single event or may accumulate over time if multiple exposure events occur. The traditional approach of assessing risk from a single chemica...

16

Modeling Malaria  

NSDL National Science Digital Library

In this module, we develop models of the effects of malaria on various populations of humans and mosquitoes. After considering differential equations to model a system, we create a model using the systems modeling tool STELLA. Projects involve various refinements of the model.

Angela B. Shiflet

17

Ionospheric modeling  

Microsoft Academic Search

The purpose of this report is to familiarize a user of ionospheric models with the options presently available for ionospheric prediction and specification. Two types of ionospheric models are available: the numerical-phenomenological and theoretical models. From the numerical type, the ITS-78, IONCAP, and Bent models have been discussed. In the theoretical models the main concern is the number of parameters

B. S. Dandekar

1982-01-01

18

Fair Model  

NSDL National Science Digital Library

The Fair model web site includes a freely available United States macroeconomic econometric model and a multicounty econometric model. The models run on the Windows OS. Instructors can use the models to teach forecasting, run policy experiments, and evaluate historical episodes of macroeconomic behavior. The web site includes extensive documentation for both models. The simulation is for upper-division economics courses in macroeconomics or econometrics. The principle developer is Ray Fair at Yale University.

Blecha, Betty

19

Supermatrix models  

SciTech Connect

Radom matrix models based on an integral over supermatrices are proposed as a natural extension of bosonic matrix models. The subtle nature of superspace integration allows these models to have very different properties from the analogous bosonic models. Two choices of integration slice are investigated. One leads to a perturbative structure which is reminiscent of, and perhaps identical to, the usual Hermitian matrix models. Another leads to an eigenvalue reduction which can be described by a two component plasma in one dimension. A stationary point of the model is described.

Yost, S.A.

1991-05-01

20

MODELS - 3  

EPA Science Inventory

Models-3 is a third generation air quality modeling system that contains a variety of tools to perform research and analysis of critical environmental questions and problems. These tools provide regulatory analysts and scientists with quicker results, greater scientific accuracy ...

21

Landscape Models  

NSDL National Science Digital Library

In this assignment students model different scenarios of landscape evolution using an on-line landscape evolution model. The assignment takes them through several situations involving changes in commonly modeled landscape variables like overland flow, faulting and uplift, erosivity, and drainage incision. At the end I have students devise a situation (of variables) that tests a hypothesis or the sensitivity of the model to changes in a variable. Designed for a geomorphology course Uses online and/or real-time data

Marchetti, David

22

Phoenix model  

EPA Science Inventory

Phoenix (formerly referred to as the Second Generation Model or SGM) is a global general equilibrium model designed to analyze energy-economy-climate related questions and policy implications in the medium- to long-term. This model disaggregates the global economy into 26 industr...

23

Animal models.  

PubMed

Epilepsy accounts for a significant portion of the dis-ease burden worldwide. Research in this field is fundamental and mandatory. Animal models have played, and still play, a substantial role in understanding the patho-physiology and treatment of human epilepsies. A large number and variety of approaches are available, and they have been applied to many animals. In this chapter the in vitro and in vivo animal models are discussed,with major emphasis on the in vivo studies. Models have used phylogenetically different animals - from worms to monkeys. Our attention has been dedicated mainly to rodents.In clinical practice, developmental aspects of epilepsy often differ from those in adults. Animal models have often helped to clarify these differences. In this chapter, developmental aspects have been emphasized.Electrical stimulation and chemical-induced models of seizures have been described first, as they represent the oldest and most common models. Among these models, kindling raised great interest, especially for the study of the epileptogenesis. Acquired focal models mimic seizures and occasionally epilepsies secondary to abnormal cortical development, hypoxia, trauma, and hemorrhage.Better knowledge of epileptic syndromes will help to create new animal models. To date, absence epilepsy is one of the most common and (often) benign forms of epilepsy. There are several models, including acute pharmacological models (PTZ, penicillin, THIP, GBL) and chronic models (GAERS, WAG/Rij). Although atypical absence seizures are less benign, thus needing more investigation, only two models are so far available (AY-9944,MAM-AY). Infantile spasms are an early childhood encephalopathy that is usually associated with a poor out-come. The investigation of this syndrome in animal models is recent and fascinating. Different approaches have been used including genetic (Down syndrome,ARX mutation) and acquired (multiple hit, TTX, CRH,betamethasone-NMDA) models.An entire section has been dedicated to genetic models, from the older models obtained with spontaneous mutations (GEPRs) to the new engineered knockout, knocking, and transgenic models. Some of these models have been created based on recently recognized patho-genesis such as benign familial neonatal epilepsy, early infantile encephalopathy with suppression bursts, severe myoclonic epilepsy of infancy, the tuberous sclerosis model, and the progressive myoclonic epilepsy. The contribution of animal models to epilepsy re-search is unquestionable. The development of further strategies is necessary to find novel strategies to cure epileptic patients, and optimistically to allow scientists first and clinicians subsequently to prevent epilepsy and its consequences. PMID:22938964

Coppola, Antonietta; Moshé, Solomon L

2012-01-01

24

Hydrological models are mediating models  

NASA Astrophysics Data System (ADS)

Despite the increasing role of models in hydrological research and decision-making processes, only few accounts of the nature and function of models exist in hydrology. Earlier considerations have traditionally been conducted while making a clear distinction between physically-based and conceptual models. A new philosophical account, primarily based on the fields of physics and economics, transcends classes of models and scientific disciplines by considering models as "mediators" between theory and observations. The core of this approach lies in identifying models as (1) being only partially dependent on theory and observations, (2) integrating non-deductive elements in their construction, and (3) carrying the role of instruments of scientific enquiry about both theory and the world. The applicability of this approach to hydrology is evaluated in the present article. Three widely used hydrological models, each showing a different degree of apparent physicality, are confronted to the main characteristics of the "mediating models" concept. We argue that irrespective of their kind, hydrological models depend on both theory and observations, rather than merely on one of these two domains. Their construction is additionally involving a large number of miscellaneous, external ingredients, such as past experiences, model objectives, knowledge and preferences of the modeller, as well as hardware and software resources. We show that hydrological models convey the role of instruments in scientific practice by mediating between theory and the world. It results from these considerations that the traditional distinction between physically-based and conceptual models is necessarily too simplistic and refers at best to the stage at which theory and observations are steering model construction. The large variety of ingredients involved in model construction would deserve closer attention, for being rarely explicitly presented in peer-reviewed literature. We believe that devoting more importance to identifying and communicating on the many factors involved in model development might increase transparency of model building.

Babel, L. V.; Karssenberg, D.

2013-08-01

25

Model Experiments and Model Descriptions  

NASA Technical Reports Server (NTRS)

The Second Workshop on Stratospheric Models and Measurements Workshop (M&M II) is the continuation of the effort previously started in the first Workshop (M&M I, Prather and Remsberg [1993]) held in 1992. As originally stated, the aim of M&M is to provide a foundation for establishing the credibility of stratospheric models used in environmental assessments of the ozone response to chlorofluorocarbons, aircraft emissions, and other climate-chemistry interactions. To accomplish this, a set of measurements of the present day atmosphere was selected. The intent was that successful simulations of the set of measurements should become the prerequisite for the acceptance of these models as having a reliable prediction for future ozone behavior. This section is divided into two: model experiment and model descriptions. In the model experiment, participant were given the charge to design a number of experiments that would use observations to test whether models are using the correct mechanisms to simulate the distributions of ozone and other trace gases in the atmosphere. The purpose is closely tied to the needs to reduce the uncertainties in the model predicted responses of stratospheric ozone to perturbations. The specifications for the experiments were sent out to the modeling community in June 1997. Twenty eight modeling groups responded to the requests for input. The first part of this section discusses the different modeling group, along with the experiments performed. Part two of this section, gives brief descriptions of each model as provided by the individual modeling groups.

Jackman, Charles H.; Ko, Malcolm K. W.; Weisenstein, Debra; Scott, Courtney J.; Shia, Run-Lie; Rodriguez, Jose; Sze, N. D.; Vohralik, Peter; Randeniya, Lakshman; Plumb, Ian

1999-01-01

26

Station Models  

NSDL National Science Digital Library

This project will allow users to become acquainted with station models that are found on weather maps. Students will study the various atmospheric variables that are depicted on a station model and then practice on an interactive station model program. Part 1 - Being able to read and interpret weather maps is a very important skill in meteorology. One of the most basic skills of predicting the weather is being able to interpret a station model of a given location. A station model is a bundle of information that ...

Ertl, Mr.

2007-11-03

27

Modeling & Simulation  

NSDL National Science Digital Library

Modeling & Simulation is a journal published by The Society for Modeling and Simulation International. The Society has made its 2004 Modeling and Simulation Resource Guide available free to download. The directory provides descriptions and contact information for the many modeling and simulation software packages currently available, as well as listings for various modeling and simulation organizations worldwide. Two guest articles describe techniques for the application of real-time simulation in simulations that are complex. Previously published articles are also posted in the online archive.

28

Computer Models  

NSDL National Science Digital Library

This undergraduate meteorology tutorial from Texas A&M University focuses on computer models that are run by the National Weather Service (NWS) National Centers for Environmental Prediction (NCEP) and are used for forecasting day-to-day weather in the United States. NCEP has four basic models: the Eta Model, the Nested Grid model (NGM), the Rapid Update Cycle (RUC), and the Global Forecast System (GFS). Each model is a self-contained set of computer programs, which include means of analyzing data and computing the evolution of the atmosphere's winds, temperature, pressure, and moisture based on the analyses. Students are given some basic terminology and learn to identify the models and to read model output.

Nielsen-Gammon, John

1996-01-01

29

ICRF modelling  

SciTech Connect

This lecture provides a survey of the methods used to model fast magnetosonic wave coupling, propagation, and absorption in tokamaks. The validity and limitations of three distinct types of modelling codes, which will be contrasted, include discrete models which utilize ray tracing techniques, approximate continuous field models based on a parabolic approximation of the wave equation, and full field models derived using finite difference techniques. Inclusion of mode conversion effects in these models and modification of the minority distribution function will also be discussed. The lecture will conclude with a presentation of time-dependent global transport simulations of ICRF-heated tokamak discharges obtained in conjunction with the ICRF modelling codes. 52 refs., 15 figs.

Phillips, C.K.

1985-12-01

30

Turbulence modeling  

NASA Technical Reports Server (NTRS)

The performance of existing two-equation eddy viscosity models was examined. An effort was made to develop better models for near-wall turbulence using direct numerical simulations of plane channel and boundary layer flows. The asymptotic near-wall behavior of turbulence was used to examine the problems of current second order closure models and develop new models with the correct near-wall behavior. Rapid Distortion Theory was used to analytically study the effects of mean deformation on turbulence, obtain analytical solutions for the spectrum tensor, Reynolds stress tensor, anisotropy tensor and its invariants, which can be used in the turbulence model development. The potential of the renormalization group theory in turbulence modeling was studied, as well as compressible turbulent flows, and modeling of bypass transition.

Shih, Tsan-Hsing

1991-01-01

31

Functions and Models: Mathematical Models  

NSDL National Science Digital Library

Describe the process of mathematical modeling;Name and describe some methods of modeling;Classify a symbolically represented function as one of the elementary algebraic or transcendental functions;Appraise the suitability of different models for interpreting a given set of data.

Michael Freeze

32

Climate Models  

NASA Technical Reports Server (NTRS)

Climate models is a very broad topic, so a single volume can only offer a small sampling of relevant research activities. This volume of 14 chapters includes descriptions of a variety of modeling studies for a variety of geographic regions by an international roster of authors. The climate research community generally uses the rubric climate models to refer to organized sets of computer instructions that produce simulations of climate evolution. The code is based on physical relationships that describe the shared variability of meteorological parameters such as temperature, humidity, precipitation rate, circulation, radiation fluxes, etc. Three-dimensional climate models are integrated over time in order to compute the temporal and spatial variations of these parameters. Model domains can be global or regional and the horizontal and vertical resolutions of the computational grid vary from model to model. Considering the entire climate system requires accounting for interactions between solar insolation, atmospheric, oceanic and continental processes, the latter including land hydrology and vegetation. Model simulations may concentrate on one or more of these components, but the most sophisticated models will estimate the mutual interactions of all of these environments. Advances in computer technology have prompted investments in more complex model configurations that consider more phenomena interactions than were possible with yesterday s computers. However, not every attempt to add to the computational layers is rewarded by better model performance. Extensive research is required to test and document any advantages gained by greater sophistication in model formulation. One purpose for publishing climate model research results is to present purported advances for evaluation by the scientific community.

Druyan, Leonard M.

2012-01-01

33

SCARP Model  

NSDL National Science Digital Library

SCARP is the first in a sequence of spreadsheet modeling exercises (SCARP2, LONGPRO, and GLACPRO). In this exercise, students use a simple arithmetic model (a running mean) to simulate the evolution of a scarp (escarpment) across time. Although the output closely resembles an evolving scarp, no real variables are included in the model. The purpose of the exercise, in addition to the simulation, is to develop basic skills in spreadsheeting and especially in graphical display.

Locke, Bill

34

Atmospheric Modeling  

Microsoft Academic Search

\\u000a Air quality models simulate the atmospheric concentrations and deposition fluxes to the Earth’s surface of air pollutants\\u000a by solving the mass conservation equations that represent the emissions, transport, dispersion, transformations and removal\\u000a of those air pollutants and associated chemical species. Contemporary air quality models can be grouped into two major categories:\\u000a (1) models that calculate the concentrations of air pollutants

Christian Seigneur; Robin Dennis

35

Floodplain Modeling  

NSDL National Science Digital Library

Students explore the impact of changing river volumes and different floodplain terrain in experimental trials with table top-sized riverbed models. The models are made using modeling clay in aluminum baking pans placed on a slight incline. Water added "upstream" at different flow rates and to different riverbed configurations simulates different potential flood conditions. Students study flood dynamics as they modify the riverbed with blockages or levees to simulate real-world scenarios.

Integrated Teaching And Learning Program

36

Cloud Modeling  

NASA Technical Reports Server (NTRS)

Numerical cloud models have been developed and applied extensively to study cloud-scale and mesoscale processes during the past four decades. The distinctive aspect of these cloud models is their ability to treat explicitly (or resolve) cloud-scale dynamics. This requires the cloud models to be formulated from the non-hydrostatic equations of motion that explicitly include the vertical acceleration terms since the vertical and horizontal scales of convection are similar. Such models are also necessary in order to allow gravity waves, such as those triggered by clouds, to be resolved explicitly. In contrast, the hydrostatic approximation, usually applied in global or regional models, does allow the presence of gravity waves. In addition, the availability of exponentially increasing computer capabilities has resulted in time integrations increasing from hours to days, domain grids boxes (points) increasing from less than 2000 to more than 2,500,000 grid points with 500 to 1000 m resolution, and 3-D models becoming increasingly prevalent. The cloud resolving model is now at a stage where it can provide reasonably accurate statistical information of the sub-grid, cloud-resolving processes poorly parameterized in climate models and numerical prediction models.

Tao, Wei-Kuo; Moncrieff, Mitchell; Einaud, Franco (Technical Monitor)

2001-01-01

37

Ventilation Model  

SciTech Connect

The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. The purposes of Revision 01 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of the discretization (Section 6.2.3.1), and the downstream applicability of the model results (i.e. wall heat fractions) to initialize post-closure thermal models (Section 6.6). (3) To satisfy the remainder of KTI agreement TEF 2.07 (Reamer and Williams 2001b). Specifically to provide the results of post-test ANSYS modeling of the Atlas Facility forced convection tests (Section 7.1.2). This portion of the model report also serves as a validation exercise per AP-SIII.10Q, Models, for the ANSYS ventilation model. (4) To further satisfy KTI agreements RDTME 3.01 and 3.14 (Reamer and Williams 2001a) by providing the source documentation referred to in the KTI Letter Report, ''Effect of Forced Ventilation on Thermal-Hydrologic Conditions in the Engineered Barrier System and Near Field Environment'' (Williams 2002). Specifically to provide the results of the MULTIFLUX model which simulates the coupled processes of heat and mass transfer in and around waste emplacement drifts during periods of forced ventilation. This portion of the model report is presented as an Alternative Conceptual Model with a numerical application, and also provides corroborative results used for model validation purposes (Section 6.3 and 6.4).

V. Chipman

2002-10-05

38

Model Selection for Geostatistical Models  

SciTech Connect

We consider the problem of model selection for geospatial data. Spatial correlation is typically ignored in the selection of explanatory variables and this can influence model selection results. For example, the inclusion or exclusion of particular explanatory variables may not be apparent when spatial correlation is ignored. To address this problem, we consider the Akaike Information Criterion (AIC) as applied to a geostatistical model. We offer a heuristic derivation of the AIC in this context and provide simulation results that show that using AIC for a geostatistical model is superior to the often used approach of ignoring spatial correlation in the selection of explanatory variables. These ideas are further demonstrated via a model for lizard abundance. We also employ the principle of minimum description length (MDL) to variable selection for the geostatistical model. The effect of sampling design on the selection of explanatory covariates is also explored.

Hoeting, Jennifer A.; Davis, Richard A.; Merton, Andrew A.; Thompson, Sandra E.

2006-02-01

39

Daisyworld Model  

NSDL National Science Digital Library

The simulation exercise uses a STELLA-based model called Daisyworld to explore concepts associated with Earth's energy balance and climate change. Students examine the evolution of a simplified model of an imaginary planet with only two species of life on its surface -- white and black daisies -- with different albedos. The daisies can alter the temperature of the surface where they are growing.

Lovelock, James; Watson, Andrew; Bice, Dave; Dept. Of Geosciences, Penn S.

40

Minibeast Models  

NSDL National Science Digital Library

In this activity, learners create models of bugs. Learners use household materials like plastic cups and straws to create models of bugs like centipedes and spiders. The activity is covered in the first 5 pages of the document. There are also a number of related activities that introduce learners to the world of invertebrates.

The University of Plymouth

2012-06-26

41

Modeling Sunspots  

ERIC Educational Resources Information Center

Modeling in science has been studied by education researchers for decades and is now being applied broadly in school. It is among the scientific practices featured in the "Next Generation Science Standards" ("NGSS") (Achieve Inc. 2013). This article describes modeling activities in an extracurricular science club in a high…

Oh, Phil Seok; Oh, Sung Jin

2013-01-01

42

Scale Models  

NSDL National Science Digital Library

In this activity, learners explore the relative sizes and distances of objects in the solar system. Without being informed of the expected product, learners will make a Play-doh model of the Earth-Moon system, scaled to size and distance. The facilitator reveals the true identity of the system at the conclusion of the activity. During the construction phase, learners try to guess what members of the solar system their model represents. Each group receives different amounts of Play-doh, with each group assigned a color (red, blue, yellow, white). At the end, groups set up their models and inspect the models of other groups. They report patterns of scale that they notice; as the amount of Play-doh increases, for example, so do the size and distance of the model. This resource guide includes background information about the Earth to Moon ratio and solar eclipses.

McDonald Observatory

2011-01-01

43

What is a model? Why modelling?  

E-print Network

What is a model? Why modelling? Which models? What is a useful model? How done? Demo vowels Symposium on Phonetic Frontiers, PĂ©kin : Chine (2008)" #12;What is a model? Why modelling? Which models? What is a useful model? How done? Demo vowels consonants Other uses speaker anatomy speaker strategy

Boyer, Edmond

44

Model Center  

NSDL National Science Digital Library

A human is a complicated organism, and it is considered unethical to do many kinds of experiments on human subjects. For these reasons, biologists often use simpler 'model' organisms that are easy to keep and manipulate in the laboratory. Despite obvious differences, model organisms share with humans many key biochemical and physiological functions that have been conserved (maintained) by evolution. Each of the following model organisms has its advantages and disadvantages in different research applications. This tool allows you to examine the similarities between different systems by comparing the proteins they share and the proportion of DNA they have in common. Choose a gene from the drop-down menu and select the species you want to compare. Rolling over the images will give you a more detailed description of each model. Clicking on a geneĂ¢ĂÂĂÂs name will take you to the National Center for Biological Information, where you can explore the latest relevant scientific literature.

2009-04-14

45

Energy Models  

EPA Science Inventory

Energy models characterize the energy system, its evolution, and its interactions with the broader economy. The energy system consists of primary resources, including both fossil fuels and renewables; power plants, refineries, and other technologies to process and convert these r...

46

Supernova models  

SciTech Connect

Recent progress in understanding the observed properties of type I supernovae as a consequence of the thermonuclear detonation of white dwarf stars and the ensuing decay of the Ni-56 produced therein is reviewed. The expected nucleosynthesis and gamma-line spectra for this model of type I explosions and a model for type II explosions are presented. Finally, a qualitatively new approach to the problem of massive star death and type II supernovae based upon a combination of rotation and thermonuclear burning is discussed. While the theoretical results of existing models are predicated upon the assumption of a successful core bounce calculation and the neglect of such two-dimensional effects as rotation and magnetic fields the new model suggests an entirely different scenario in which a considerable portion of the energy carried by an equatorially ejected blob is deposited in the red giant envelope overlying the mantle of the star.

Woosley, S.E. (California, University, Santa Cruz; California, University, Livermore, CA); Weaver, T.A. (California, University, Livermore, CA)

1981-12-29

47

Modeling Quality Information within Business Process Models  

E-print Network

Modeling Quality Information within Business Process Models Robert Heinrich, Alexander Kappe. Business process models are a useful means to document information about structure and behavior literature and tool survey on modeling quality information within business process models. Keywords: Business

Paech, Barbara

48

Device modeling  

NASA Technical Reports Server (NTRS)

A summary report is given of the activities of the device modeling workshop which was held as a part of the Space Photovoltaic Research and Technology Conference at the Lewis Research Center, October 7 to 9, 1986. The purpose of this workshop was to access the status of solar cell device modeling to see if it is meeting present and future needs of the photovoltaic community.

Schwartz, Richard

1987-01-01

49

Time-dependent isospin composition of particles emitted in fission events following Ar40+Au197 at 35 MeV/u  

NASA Astrophysics Data System (ADS)

Fission fragments resulting from the fission of target-like nuclei produced in the Ar40+Au197 reaction at 35 MeV/u are measured in coincidence with the emitted light charged particles (LCPs). Comparison of the N /Z composition of the LCPs at middle and large angles in the laboratory frame shows that particles emitted at smaller angles, which contain a larger contribution from dynamical emission, are more neutron rich. A moving-source model is used to fit the energy spectra of the hydrogen isotopes. A hierarchy from proton to deuteron and triton is observed in the multiplicity ratio between the intermediate velocity source and the compound nucleus source. This ratio is sensitive to the dynamical emission at early stages of the reaction and to statistical emission lasting up to the scission point. Calculations with the improved quantum molecular dynamics (ImQMD) transport-model qualitatively support the picture that more free and bound neutrons are emitted during the early stage, showing a clear dependence of N /Z on the parametrization of the symmetry energy. The time-dependent isospin composition of the emitted particles thus may be used to probe the symmetry energy at subsaturation densities.

Wang, R. S.; Zhang, Y.; Xiao, Z. G.; Tian, J. L.; Zhang, Y. X.; Wu, Q. H.; Duan, L. M.; Jin, G. M.; Hu, R. J.; Wang, S. F.; Li, Z. Y.; Wang, H. W.; Zhang, Z.; Yi, H.; Li, H. J.; Cheng, W. J.; Huang, Y.; Lü, L. M.

2014-06-01

50

Mechanistic models  

SciTech Connect

Several models and theories are reviewed that incorporate the idea of radiation-induced lesions (repairable and/or irreparable) that can be related to molecular lesions in the DNA molecule. Usually the DNA double-strand or chromatin break is suggested as the critical lesion. In the models, the shoulder on the low-LET survival curve is hypothesized as being due to one (or more) of the following three mechanisms: (1) ``interaction`` of lesions produced by statistically independent particle tracks; (2) nonlinear (i.e., linear-quadratic) increase in the yield of initial lesions, and (3) saturation of repair processes at high dose. Comparisons are made between the various approaches. Several significant advances in model development are discussed; in particular, a description of the matrix formulation of the Markov versions of the RMR and LPL models is given. The more advanced theories have incorporated statistical fluctuations in various aspects of the energy-loss and lesion-formation process. An important direction is the inclusion of physical and chemical processes into the formulations by incorporating relevant track structure theory (Monte Carlo track simulations) and chemical reactions of radiation-induced radicals. At the biological end, identification of repair genes and how they operate as well as a better understanding of how DNA misjoinings lead to lethal chromosome aberrations are needed for appropriate inclusion into the theories. More effort is necessary to model the complex end point of radiation-induced carcinogenesis.

Curtis, S.B.

1990-09-01

51

Mechanistic models  

SciTech Connect

Several models and theories are reviewed that incorporate the idea of radiation-induced lesions (repairable and/or irreparable) that can be related to molecular lesions in the DNA molecule. Usually the DNA double-strand or chromatin break is suggested as the critical lesion. In the models, the shoulder on the low-LET survival curve is hypothesized as being due to one (or more) of the following three mechanisms: (1) interaction'' of lesions produced by statistically independent particle tracks; (2) nonlinear (i.e., linear-quadratic) increase in the yield of initial lesions, and (3) saturation of repair processes at high dose. Comparisons are made between the various approaches. Several significant advances in model development are discussed; in particular, a description of the matrix formulation of the Markov versions of the RMR and LPL models is given. The more advanced theories have incorporated statistical fluctuations in various aspects of the energy-loss and lesion-formation process. An important direction is the inclusion of physical and chemical processes into the formulations by incorporating relevant track structure theory (Monte Carlo track simulations) and chemical reactions of radiation-induced radicals. At the biological end, identification of repair genes and how they operate as well as a better understanding of how DNA misjoinings lead to lethal chromosome aberrations are needed for appropriate inclusion into the theories. More effort is necessary to model the complex end point of radiation-induced carcinogenesis.

Curtis, S.B.

1990-09-01

52

Gnomon Model  

NSDL National Science Digital Library

The EJS Gnomon model simulates the shadow cast by a gnomon (the part of a sundial that casts the shadow) over the course of a day for any day of the year and any latitude on Earth. The program gives you the option to use mean Sun (which moves relative to the stars at a constant rate throughout the year) or true Sun (which varies its apparent speed relative to the background stars). The default is to use true Sun. The program also shows the observer's horizon plane on the spherical Earth, as well as the ecliptic and the apparent path of Sun. The Earth View can be set to let Earth rotate or remain fixed EJS Gnomon model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_Gnomon.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for astronomy are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Timberlake, Todd

2009-08-19

53

Modeling reality  

NASA Technical Reports Server (NTRS)

Although powerful computers have allowed complex physical and manmade hardware systems to be modeled successfully, we have encountered persistent problems with the reliability of computer models for systems involving human learning, human action, and human organizations. This is not a misfortune; unlike physical and manmade systems, human systems do not operate under a fixed set of laws. The rules governing the actions allowable in the system can be changed without warning at any moment, and can evolve over time. That the governing laws are inherently unpredictable raises serious questions about the reliability of models when applied to human situations. In these domains, computers are better used, not for prediction and planning, but for aiding humans. Examples are systems that help humans speculate about possible futures, offer advice about possible actions in a domain, systems that gather information from the networks, and systems that track and support work flows in organizations.

Denning, Peter J.

1990-01-01

54

Modelling osteomyelitis  

PubMed Central

Background This work focuses on the computational modelling of osteomyelitis, a bone pathology caused by bacteria infection (mostly Staphylococcus aureus). The infection alters the RANK/RANKL/OPG signalling dynamics that regulates osteoblasts and osteoclasts behaviour in bone remodelling, i.e. the resorption and mineralization activity. The infection rapidly leads to severe bone loss, necrosis of the affected portion, and it may even spread to other parts of the body. On the other hand, osteoporosis is not a bacterial infection but similarly is a defective bone pathology arising due to imbalances in the RANK/RANKL/OPG molecular pathway, and due to the progressive weakening of bone structure. Results Since both osteoporosis and osteomyelitis cause loss of bone mass, we focused on comparing the dynamics of these diseases by means of computational models. Firstly, we performed meta-analysis on a gene expression data of normal, osteoporotic and osteomyelitis bone conditions. We mainly focused on RANKL/OPG signalling, the TNF and TNF receptor superfamilies and the NF-kB pathway. Using information from the gene expression data we estimated parameters for a novel model of osteoporosis and of osteomyelitis. Our models could be seen as a hybrid ODE and probabilistic verification modelling framework which aims at investigating the dynamics of the effects of the infection in bone remodelling. Finally we discuss different diagnostic estimators defined by formal verification techniques, in order to assess different bone pathologies (osteopenia, osteoporosis and osteomyelitis) in an effective way. Conclusions We present a modeling framework able to reproduce aspects of the different bone remodeling defective dynamics of osteomyelitis and osteoporosis. We report that the verification-based estimators are meaningful in the light of a feed forward between computational medicine and clinical bioinformatics. PMID:23095605

2012-01-01

55

Supernova models  

SciTech Connect

Recent progress in understanding the observed properties of Type I supernovae as a consequence of the thermonuclear detonation of white dwarf stars and the ensuing decay of the /sup 56/Ni produced therein is reviewed. Within the context of this model for Type I explosions and the 1978 model for Type II explosions, the expected nucleosynthesis and gamma-line spectra from both kinds of supernovae are presented. Finally, a qualitatively new approach to the problem of massive star death and Type II supernovae based upon a combination of rotation and thermonuclear burning is discussed.

Woosley, S.E.; Weaver, T.A.

1980-01-01

56

Fission of actinides through quasimolecular shapes  

NASA Astrophysics Data System (ADS)

The potential energy of heavy nuclei has been calculated in the quasimolecular shape path from a generalized liquid drop model including the proximity energy, the charge and mass asymmetries and the microscopic corrections. The potential barriers are multiple-humped. The second maximum is the saddle-point. It corresponds to the transition from compact one-body shapes with a deep neck to two touching ellipsoids. The scission point lies at the end of an energy plateau well below the saddle-point and where the effects of the nuclear attractive forces between two separated fragments vanish. The energy on this plateau is the sum of the kinetic and excitation energies of the fragments. The shell and pairing corrections play an essential role to select the most probable fission path. The potential barrier heights agree with the experimental data and the theoretical half-lives follow the trend of the experimental values. A third peak and a shallow third minimum appear in asymmetric decay paths when one fragment is close to a double magic quasi-spherical nucleus, while the smaller one changes from oblate to prolate shapes.

Royer, Guy; Zhang, Hongfei; Eudes, Philippe; Moustabchir, Rachid; Moreau, Damien; Jaffré, Muriel; Morabit, Youssef; Particelli, Benjamin

2013-12-01

57

Marshmallow Models  

NSDL National Science Digital Library

No glue is needed for learners of any age to become marshmallow architects or engineers. Using marshmallows and water (and maybe edible decorations like peanut butter, pretzels, gumdrops, etc.), learners wet a few marshamallows at a time and stick them together bit by bit to construct whatever models they want.

Science, Lawrence H.

2010-01-01

58

Ensemble Models  

EPA Science Inventory

Ensemble forecasting has been used for operational numerical weather prediction in the United States and Europe since the early 1990s. An ensemble of weather or climate forecasts is used to characterize the two main sources of uncertainty in computer models of physical systems: ...

59

Why model?  

PubMed Central

Next generation sequencing technologies are bringing about a renaissance of mining approaches. A comprehensive picture of the genetic landscape of an individual patient will be useful, for example, to identify groups of patients that do or do not respond to certain therapies. The high expectations may however not be satisfied if the number of patient groups with similar characteristics is going to be very large. I therefore doubt that mining sequence data will give us an understanding of why and when therapies work. For understanding the mechanisms underlying diseases, an alternative approach is to model small networks in quantitative mechanistic detail, to elucidate the role of gene and proteins in dynamically changing the functioning of cells. Here an obvious critique is that these models consider too few components, compared to what might be relevant for any particular cell function. I show here that mining approaches and dynamical systems theory are two ends of a spectrum of methodologies to choose from. Drawing upon personal experience in numerous interdisciplinary collaborations, I provide guidance on how to model by discussing the question “Why model?” PMID:24478728

Wolkenhauer, Olaf

2013-01-01

60

Modeling Muscles  

ERIC Educational Resources Information Center

Teaching the anatomy of the muscle system to high school students can be challenging. Students often learn about muscle anatomy by memorizing information from textbooks or by observing plastic, inflexible models. Although these mediums help students learn about muscle placement, the mediums do not facilitate understanding regarding integration of…

Goodwyn, Lauren; Salm, Sarah

2007-01-01

61

Groundwater Model  

NSDL National Science Digital Library

In this activity, students build a model to demonstrate how aquifers are formed and ground water becomes polluted. For younger students, the teacher can perform this activity as a demonstration, or older students can perform it themselves. A materials list, instructions, and extension activities are provided.

62

Modeling Convection  

ERIC Educational Resources Information Center

Students must understand the fundamental process of convection before they can grasp a wide variety of Earth processes, many of which may seem abstract because of the scales on which they operate. Presentation of a very visual, concrete model prior to instruction on these topics may facilitate students' understanding of processes that are largely…

Ebert, James R.; Elliott, Nancy A.; Hurteau, Laura; Schulz, Amanda

2004-01-01

63

Urban Modelling  

Microsoft Academic Search

Urban models are computer-based simulations used for testing theories about spatial location and interaction between land uses and related activities. They also provide digital environments for testing the consequences of physical planning policies on the future form of cities. As computers, software and data have become richer, and as our conception of the way complex systems such as cities grow

Michael Batty; Rob Kitchin; Nigel Thrift

64

Daisyworld Model  

NSDL National Science Digital Library

The Daisyworld model created by Andrew Watson and James Lovelock (1983, Tellus, v. 35B, p. 284-289) is a wonderful example of a self-regulating system incorporating positive and negative feedbacks. The model consists of a planet on which black and white daisies are growing. The growth of these daisies is governed by a parabolic shaped growth function regulated by planetary temperature and is set to zero for temperatures less than 5 ÂşC or greater than 40 ÂşC and optimized at 22.5 ÂşC. The model explores the effect of a steadily increasing solar luminosity on the growth of daisies and the resulting planetary temperature. The growth function for the daisies allows them to modulate the planet's temperature for many years, warming it early on as black daisies grow, and cooling it later as white daisies grow. Eventually, the solar luminosity increases beyond the daisies' capability to modulate the temperature and they die out, leading to a rapid rise in the planetary temperature. Students read Watson and Lovelock's original paper, and then use STELLA to create their own Daisyworld model with which they can experiment. Experiments include changing the albedos of the daisies, changing their death rates, and changing the rate at which energy is conducted from one part of the planet to another. In all cases, students keep track of daisy populations and of planetary temperature over time.

Menking, Kirsten

65

Atmospheric Modeling  

EPA Science Inventory

Although air quality models have been applied historically to address issues specific to ambient air quality standards (i.e., one criteria pollutant at a time) or welfare (e.g.. acid deposition or visibility impairment). they are inherently multipollutant based. Therefore. in pri...

66

ATMOSPHERIC MODELING: MODEL AND ACCURACY  

EPA Science Inventory

The development of models to assess the emission control requirements of primary precursor pollutants in the production of photochemical oxidants has been underway for approximately 20 years. Over the period there has been a considerable increase in our understanding of the basic...

67

Linear Models  

NSDL National Science Digital Library

This site uses linear models to demonstrate the change in bird populations on a barren island over time, supply and demand, and the natural cleaning of a polluted lake by fresh water over time. The problems are laid out and turned into both graphic and equation form in order to understand the rate of change happening in each scenario. There are also links to previously covered materials that can help student review material from past math lessons.

Frank Wattenberg

1997-01-01

68

Geometric Models  

NSDL National Science Digital Library

Created by Kyle Siegrist of the University of Alabama-Huntsville, this is an online, interactive lesson on geometric models. The author provides examples, exercises, and applets which include Buffon's problems, Bertrand's paradox, and random triangles. Additionally, the author provides links to external resources for students wanting to engage further in this topic. This is simply one lesson in a series of seventeen. They are all easily accessible as the author has formated his site much like an online textbook.

Siegrist, Kyle

69

10. MOVABLE BED SEDIMENTATION MODELS. DOGTOOTH BEND MODEL (MODEL SCALE: ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. MOVABLE BED SEDIMENTATION MODELS. DOGTOOTH BEND MODEL (MODEL SCALE: 1' = 400' HORIZONTAL, 1' = 100' VERTICAL), AND GREENVILLE BRIDGE MODEL (MODEL SCALE: 1' = 360' HORIZONTAL, 1' = 100' VERTICAL). - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

70

Eratosthenes Model  

NSDL National Science Digital Library

The Eratosthenes model displays the shadows cast by two gnomons (sticks) at different locations on Earth. For one gnomon, Sun is directly overhead (as would be the case if the gnomon was on the Tropic of Cancer at the summer solstice). The other gnomon is due north of the first gnomon. The sizes of the gnomons are greatly exaggerated for visibility. This simulation can be used to help illustrate how Eratosthenes was able to measure the diameter of Earth using the shadows cast by two gnomons, one situated due north of the other, on a day when the southerly gnomon cast no shadow at all. The distance between the two gnomons (along Earth's surface) can be adjusted. The length of the shadow is given, and this length can be used to determine the angle between the gnomon lines and from that the circumference (and diameter, radius, etc) of Earth. Earth can be hidden to give a better view of the relevant geometry. Eratosthenes model is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_Eratosthenes.jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the plot and selecting "Open EJS Model" from the pop-up menu item.

Timberlake, Todd

2010-01-03

71

Modeling biomembranes.  

SciTech Connect

Understanding the properties and behavior of biomembranes is fundamental to many biological processes and technologies. Microdomains in biomembranes or ''lipid rafts'' are now known to be an integral part of cell signaling, vesicle formation, fusion processes, protein trafficking, and viral and toxin infection processes. Understanding how microdomains form, how they depend on membrane constituents, and how they act not only has biological implications, but also will impact Sandia's effort in development of membranes that structurally adapt to their environment in a controlled manner. To provide such understanding, we created physically-based models of biomembranes. Molecular dynamics (MD) simulations and classical density functional theory (DFT) calculations using these models were applied to phenomena such as microdomain formation, membrane fusion, pattern formation, and protein insertion. Because lipid dynamics and self-organization in membranes occur on length and time scales beyond atomistic MD, we used coarse-grained models of double tail lipid molecules that spontaneously self-assemble into bilayers. DFT provided equilibrium information on membrane structure. Experimental work was performed to further help elucidate the fundamental membrane organization principles.

Plimpton, Steven James; Heffernan, Julieanne; Sasaki, Darryl Yoshio; Frischknecht, Amalie Lucile; Stevens, Mark Jackson; Frink, Laura J. Douglas

2005-11-01

72

General Model Independent Normal Model Correlated Normal Model Conclusion Sequential Bayesian Ranking and Selection with  

E-print Network

General Model Independent Normal Model Correlated Normal Model Conclusion Sequential Bayesian;General Model Independent Normal Model Correlated Normal Model Conclusion Example, Time 0 #12;General Model Independent Normal Model Correlated Normal Model Conclusion Example, Time 1 #12;General Model

Keinan, Alon

73

Molecular Modeling  

NASA Astrophysics Data System (ADS)

Molecular modeling has trickled down from the realm of pharmaceutical and research laboratories into the realm of undergraduate chemistry instruction. It has opened avenues for the visualization of chemical concepts that previously were difficult or impossible to convey. I am sure that many of you have developed exercises using the various molecular modeling tools. It is the desire of this Journal to become an avenue for you to share these exercises among your colleagues. It is to this end that Ron Starkey has agreed to edit such a column and to publish not only the description of such exercises, but also the software documents they use. The WWW is the obvious medium to distribute this combination and so accepted submissions will appear online as a feature of JCE Internet. Typical molecular modeling exercise: finding conformation energies. Molecular Modeling Exercises and Experiments is the latest feature column of JCE Internet, joining Conceptual Questions and Challenge Problems, Hal's Picks, and Mathcad in the Chemistry Curriculum. JCE Internet continues to seek submissions in these areas of interest and submissions of general interest. If you have developed materials and would like to submit them, please see our Guide to Submissions for more information. The Chemical Education Resource Shelf, Equipment Buyers Guide, and WWW Site Review would also like to hear about chemistry textbooks and software, equipment, and WWW sites, respectively. Please consult JCE Internet Features to learn more about these resources at JCE Online. Email Announcements Would you like to be informed by email when the latest issue of the Journal is available online? when a new JCE Software title is shipping? when a new JCE Internet article has been published or is available for Open Review? when your subscription is about to expire? A new feature of JCE Online makes this possible. Visit our Guestbook to learn how. When you submit the form on this page, which includes your email address, you may choose to receive an email notice about a Journal event that interests you. Currently such events include availability of the latest issue of the Journal at JCE Online, expiration of your Journal subscription, shipment of a new JCE Software issue, publication of a new JCE Internet article or its availability for Open Review, and other announcements from the Journal. You may choose any number of these options independently. JCE Online Guestbook. Your Privacy JCE Online promises to you that we will not use the information that you provide in our Guestbook for anything other than our own internal information. We will not provide this information to third parties. We will use the information you provide only in our effort to help make the JCE serve you better. You only need to provide your email address to take advantage of this service; the other information you provide is optional. Molecular Modeling Exercises and Experiments: Mission Statement We are seeking in this JCE Internet feature column to publish molecular modeling exercises and experiments that have been used successfully in undergraduate instruction. The exercises will be published here on JCE Internet. An abstract of published submissions will appear in print in the Journal of Chemical Education. Acceptable exercises could be used in either a chemistry laboratory or a chemistry computer laboratory. The exercise could cover any area of chemistry, but should be limited to undergraduate instructional applications. We envision that most of the exercises/experiments will utilize one of the popular instructional molecular modeling software programs (e.g. HyperChem, Spartan, CAChe, PC Model). Exercises that are specific to a particular modeling program are acceptable, but those usable with any modeling program are preferred. Ideally the exercises/experiments will be of the type where the "correct"answer is not obvious so

Holmes, Jon L.

1999-06-01

74

Atomic Models, Nagaoka's Saturnian Model  

Microsoft Academic Search

In late 1903, Hantaro Nagaoka (1865–1950) developed the earliest published quasi-planetary model of the atom. This graduate\\u000a of the University of Tokyo from 1887 spent his postdoctoral period in Vienna, Berlin and Munich before obtaining a professorship\\u000a in Tokyo to become Japan's foremost modern physicist. Nagaoka assumed that the atom is a large, massive, positively charged\\u000a sphere, encircled by very

Klaus Hentschel

75

Biomimetic modelling.  

PubMed Central

Biomimetics is seen as a path from biology to engineering. The only path from engineering to biology in current use is the application of engineering concepts and models to biological systems. However, there is another pathway: the verification of biological mechanisms by manufacture, leading to an iterative process between biology and engineering in which the new understanding that the engineering implementation of a biological system can bring is fed back into biology, allowing a more complete and certain understanding and the possibility of further revelations for application in engineering. This is a pathway as yet unformalized, and one that offers the possibility that engineers can also be scientists. PMID:14561351

Vincent, Julian F V

2003-01-01

76

Fraction Models  

NSDL National Science Digital Library

This interactive activity allows users the ability to explore different representations for fractions and how they are equivalent to mixed numbers, decimals, and percentages. Users adjust the numerator (up to 100) and the denominator (1 to 25) in order to see a visual representation of the fraction. The visual representation can be seen as a length, area, region, or set model. Users also have the ability to keep track of the equivalent forms of fractions in a table. Instructions and exploration questions are given.

2011-01-01

77

Constructing NARMAX models using ARMAX models  

Microsoft Academic Search

This paper outlines how it is possible to decompose a complex non-linear modelling problem into a set of simpler linear modelling problems. Local ARMAX models valid within certain operating regimes are interpolated to construct a global NARMAX (non-linear NARMAX) model. Knowledge of the system behaviour in terms of operating regimes is the primary basis for building such models, hence it

TOR A. JOHANSEN; BJARNE A. FOSS

1993-01-01

78

Pre-Modeling Ensures Accurate Solid Models  

ERIC Educational Resources Information Center

Successful solid modeling requires a well-organized design tree. The design tree is a list of all the object's features and the sequential order in which they are modeled. The solid-modeling process is faster and less prone to modeling errors when the design tree is a simple and geometrically logical definition of the modeled object. Few high…

Gow, George

2010-01-01

79

Comparisons of debris environment model breakup models  

Microsoft Academic Search

This paper presents a comparison of current spacecraft breakup models used in orbital (space) debris computational environment models. The breakup models to be compared come from the NASA EVOLVE (Evolutionary) model long term debris model, the IMPACT code developed by Aerospace Corp., and the Fragmentation Algorithms for Satellite Targets (FAST) developed by Kaman Sciences. The comparison will show the methodologies

F. Jonas; K. Yates; R. Evans

1993-01-01

80

Modelling intonational structure using hidden markov models  

E-print Network

A method is introduced for using hidden Markov models (HMMs) to model intonational structure. HMMs are probabilistic and can capture the variability in structure which previous finite state network models lack. We show ...

Wright, Helen; Taylor, Paul A

1997-01-01

81

Search for a long lived component in the reaction U+U near the Coulomb barrier  

E-print Network

into excitation energy via nuclear friction. These considerations motivated us to search for a signature low kinetic energy at the scission point. They should thus emerge out of the collision with their Coulomb barrier energy. In the language of deep inelastic scattering, this corresponds to reactions

Paris-Sud XI, Université de

82

Analytic Modeling Birth-Death Model  

E-print Network

Analytic Modeling Birth-Death Model 1 A Review -Random Variables · A variable representing on Exponential Distribution 11 Birth-Death Model 12 #12;Birth-Death Model · Queuing system with a single service State Dependent Arrival Rate 14 #12;State Dependent Service Rate 15 Definition of Birth-Death Process 16

Shihada, Basem

83

I&C Modeling in SPAR Models  

SciTech Connect

The Standardized Plant Analysis Risk (SPAR) models for the U.S. commercial nuclear power plants currently have very limited instrumentation and control (I&C) modeling [1]. Most of the I&C components in the operating plant SPAR models are related to the reactor protection system. This was identified as a finding during the industry peer review of SPAR models. While the Emergency Safeguard Features (ESF) actuation and control system was incorporated into the Peach Bottom Unit 2 SPAR model in a recent effort [2], various approaches to expend resources for detailed I&C modeling in other SPAR models are investigated.

John A. Schroeder

2012-06-01

84

Comparative Protein Structure Modeling Using Modeller  

PubMed Central

Functional characterization of a protein sequence is one of the most frequent problems in biology. This task is usually facilitated by accurate three-dimensional (3-D) structure of the studied protein. In the absence of an experimentally determined structure, comparative or homology modeling can sometimes provide a useful 3-D model for a protein that is related to at least one known protein structure. Comparative modeling predicts the 3-D structure of a given protein sequence (target) based primarily on its alignment to one or more proteins of known structure (templates). The prediction process consists of fold assignment, target-template alignment, model building, and model evaluation. This unit describes how to calculate comparative models using the program MODELLER and discusses all four steps of comparative modeling, frequently observed errors, and some applications. Modeling lactate dehydrogenase from Trichomonas vaginalis (TvLDH) is described as an example. The download and installation of the MODELLER software is also described. PMID:18428767

Eswar, Narayanan; Marti-Renom, Marc A.; Madhusudhan, M.S.; Eramian, David; Shen, Min-yi; Pieper, Ursula

2014-01-01

85

Loglinear Rasch model tests  

Microsoft Academic Search

Existing statistical tests for the fit of the Rasch model have been criticized, because they are only sensitive to specific violations of its assumptions. Contingency table methods using loglinear models have been used to test various psychometric models. In this paper, the assumptions of the Rasch model are discussed and the Rasch model is reformulated as a quasi-independence model. The

Hendrikus Kelderman

1984-01-01

86

Comparisons of debris environment model breakup models  

NASA Astrophysics Data System (ADS)

This paper presents a comparison of current spacecraft breakup models used in orbital (space) debris computational environment models. The breakup models to be compared come from the NASA EVOLVE (Evolutionary) model long term debris model, the IMPACT code developed by Aerospace Corp., and the Fragmentation Algorithms for Satellite Targets (FAST) developed by Kaman Sciences. The comparison will show the methodologies and results obtained for each model such as mass versus fragment number distributions. Implications for debris cloud formation will be discussed in terms of the environments produced. No attempt is made to recommend any one model over the other as each were designed and employed for specific purposes in the environment models they are part of or contribute to. The comparisons are intended to provide researchers both quantitative and qualitative information on the models for use in their own research activities.

Jonas, F.; Yates, K.; Evans, R.

1993-01-01

87

Uncertainty Modeling Via Frequency Domain Model Validation  

NASA Technical Reports Server (NTRS)

Abstract The majority of literature on robust control assumes that a design model is available and that the uncertainty model bounds the actual variations about the nominal model. However, methods for generating accurate design models have not received as much attention in the literature. The influence of the level of accuracy of the uncertainty model on closed loop performance has received even less attention. The research reported herein is an initial step in applying and extending the concept of model validation to the problem of obtaining practical uncertainty models for robust control analysis and design applications. An extension of model validation called 'sequential validation' is presented and applied to a simple spring-mass-damper system to establish the feasibility of the approach and demonstrate the benefits of the new developments.

Waszak, Martin R.; Andrisani, Dominick, II

1999-01-01

88

Comparison of laser models  

NASA Technical Reports Server (NTRS)

Progress on the comparison of laser models is reported. Equations for an oscillatory model and a nonoscillatory model for the simulation of iodine laser operation are solved. Reaction rate coefficients used in both models are listed. Currently there are four models for the simulation of iodine laser operation are solved. Reaction rate coefficients used in both models are listed. Currently there are four models for the simulation of an iodine laser. They are: (1) a time dependent model; (2) a quasi-steady state model; (3) a noncompressible model; and (4) a compressible flow laser model. Current research is being directed toward: (1) parameter studies using the compressible flow laser model; (2) development of a two-pass amplifier model; and (3) solving a system of equations describing operation of the high powered iodine MOPA (master oscillator power amplifier).

Heinbockel, John H.

1989-01-01

89

Model Mapping in MDA  

Microsoft Academic Search

In this paper we propose a general model of Model Mapping, one of the key features in MDA. We recall the fundamental relationships between system, model ,a ndformalism. Then mapping of models described in the same formalism (direct) or in different formalisms (indirect) is discussed. As an example, a Constraint Checker (CC) is presented. This application takes an UML model

Guy CAPLAT; Jean Louis SOURROUILLE

90

"Bohr's Atomic Model."  

ERIC Educational Resources Information Center

"Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

Willden, Jeff

2001-01-01

91

Multilevel Model Prediction  

ERIC Educational Resources Information Center

Multilevel models are proven tools in social research for modeling complex, hierarchical systems. In multilevel modeling, statistical inference is based largely on quantification of random variables. This paper distinguishes among three types of random variables in multilevel modeling--model disturbances, random coefficients, and future response…

Frees, Edward W.; Kim, Jee-Seon

2006-01-01

92

Discrete, Amorphous Physical Models  

Microsoft Academic Search

Discrete models of physical phenomena are an attractive alternative to continuous models such as partial differential equations. In discrete models, such as cellular automata, space is treated as having finitely many locations per unit volume, and physical processes are modelled by rules that depend on a small number of nearby locations. Such models depend critically on a regular (crystalline) lattice,

Erik Rauch

2003-01-01

93

Bohr model as an algebraic collective model  

SciTech Connect

Developments and applications are presented of an algebraic version of Bohr's collective model. Illustrative examples show that fully converged calculations can be performed quickly and easily for a large range of Hamiltonians. As a result, the Bohr model becomes an effective tool in the analysis of experimental data. The examples are chosen both to confirm the reliability of the algebraic collective model and to show the diversity of results that can be obtained by its use. The focus of the paper is to facilitate identification of the limitations of the Bohr model with a view to developing more realistic, computationally tractable models.

Rowe, D. J.; Welsh, T. A.; Caprio, M. A. [Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7 (Canada); Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556-5670 (United States)

2009-05-15

94

Solicited abstract: Global hydrological modeling and models  

NASA Astrophysics Data System (ADS)

The origins of rainfall-runoff modeling in the broad sense can be found in the middle of the 19th century arising in response to three types of engineering problems: (1) urban sewer design, (2) land reclamation drainage systems design, and (3) reservoir spillway design. Since then numerous empirical, conceptual and physically-based models are developed including event based models using unit hydrograph concept, Nash's linear reservoir models, HBV model, TOPMODEL, SHE model, etc. From the late 1980s, the evolution of global and continental-scale hydrology has placed new demands on hydrologic modellers. The macro-scale hydrological (global and regional scale) models were developed on the basis of the following motivations (Arenll, 1999). First, for a variety of operational and planning purposes, water resource managers responsible for large regions need to estimate the spatial variability of resources over large areas, at a spatial resolution finer than can be provided by observed data alone. Second, hydrologists and water managers are interested in the effects of land-use and climate variability and change over a large geographic domain. Third, there is an increasing need of using hydrologic models as a base to estimate point and non-point sources of pollution loading to streams. Fourth, hydrologists and atmospheric modellers have perceived weaknesses in the representation of hydrological processes in regional and global climate models, and developed global hydrological models to overcome the weaknesses of global climate models. Considerable progress in the development and application of global hydrological models has been achieved to date, however, large uncertainties still exist considering the model structure including large scale flow routing, parameterization, input data, etc. This presentation will focus on the global hydrological models, and the discussion includes (1) types of global hydrological models, (2) procedure of global hydrological model development, (3) state-of-the-art of existing global hydrological models, and (4) challenges. Acknowledgment: Thanks to Lebing Gong, Elin Widén-Nilsson, and Sven Halldin of Uppsala University for the team work in global hydrological models.

Xu, Chong-Yu

2010-05-01

95

Mathematics and Statistics Models  

NSDL National Science Digital Library

Developed by Bob MacKay, Clark College. What are Mathematical and Statistical Models These types of models are obviously related, but there are also real differences between them. Mathematical Models: grow out of ...

96

Composite Linear Models  

Cancer.gov

Statistical Software Composite Linear Models (Written by Stuart G. Baker) The composite linear models software is a matrix approach to compute maximum likelihood estimates and asymptotic standard errors for models for incomplete multinomial data. It

97

Educating with Aircraft Models  

ERIC Educational Resources Information Center

Described is utilization of aircraft models, model aircraft clubs, and model aircraft magazines to promote student interest in aerospace education. The addresses for clubs and magazines are included. (SL)

Steele, Hobie

1976-01-01

98

Modeling Natural Selection  

NSDL National Science Digital Library

In their research, scientists generate, test, and modify scientific models. These models can be shared with others and demonstrate a scientist's understanding of how the natural world works. Similarly, students can generate and modify models to gain a bet

Lotter, Christine; Bogiages, Christopher A.

2011-02-01

99

American Modeling Teachers Association  

NSDL National Science Digital Library

This is the web site home for the American Modeling Teachers Association, and organization run by and for teachers who use modeling instruction in their classroom. Modeling instruction organizes science content around a small number of of scientific models, and uses a structured inquiry approach to teaching science content and skills. This web site includes information about the Association, Modeling workshops, and discussions regarding science education. Members of the AMTA have access to Modeling teaching resources.

2013-03-20

100

Morphable Models of Faces  

Microsoft Academic Search

\\u000a In this chapter, we present the Morphable Model, a three-dimensional (3D) representation that enables the accurate modeling\\u000a of any illumination and pose as well as the separation of these variations from the rest (identity and expression). The Morphable\\u000a Model is a generative model consisting of a linear 3D shape and appearance model plus an imaging model, which maps the 3D

Reinhard Knothe; Brian Amberg; Sami Romdhani; Volker Blanz; Thomas Vetter

101

Orbital Debris Modeling  

NASA Technical Reports Server (NTRS)

Presentation outlne: (1) The NASA Orbital Debris (OD) Engineering Model -- A mathematical model capable of predicting OD impact risks for the ISS and other critical space assets (2) The NASA OD Evolutionary Model -- A physical model capable of predicting future debris environment based on user-specified scenarios (3) The NASA Standard Satellite Breakup Model -- A model describing the outcome of a satellite breakup (explosion or collision)

Liou, J. C.

2012-01-01

102

Geologic Framework Model Analysis Model Report  

SciTech Connect

The purpose of this report is to document the Geologic Framework Model (GFM), Version 3.1 (GFM3.1) with regard to data input, modeling methods, assumptions, uncertainties, limitations, and validation of the model results, qualification status of the model, and the differences between Version 3.1 and previous versions. The GFM represents a three-dimensional interpretation of the stratigraphy and structural features of the location of the potential Yucca Mountain radioactive waste repository. The GFM encompasses an area of 65 square miles (170 square kilometers) and a volume of 185 cubic miles (771 cubic kilometers). The boundaries of the GFM were chosen to encompass the most widely distributed set of exploratory boreholes (the Water Table or WT series) and to provide a geologic framework over the area of interest for hydrologic flow and radionuclide transport modeling through the unsaturated zone (UZ). The depth of the model is constrained by the inferred depth of the Tertiary-Paleozoic unconformity. The GFM was constructed from geologic map and borehole data. Additional information from measured stratigraphy sections, gravity profiles, and seismic profiles was also considered. This interim change notice (ICN) was prepared in accordance with the Technical Work Plan for the Integrated Site Model Process Model Report Revision 01 (CRWMS M&O 2000). The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. The GFM is one component of the Integrated Site Model (ISM) (Figure l), which has been developed to provide a consistent volumetric portrayal of the rock layers, rock properties, and mineralogy of the Yucca Mountain site. The ISM consists of three components: (1) Geologic Framework Model (GFM); (2) Rock Properties Model (RPM); and (3) Mineralogic Model (MM). The ISM merges the detailed project stratigraphy into model stratigraphic units that are most useful for the primary downstream models and the repository design. These downstream models include the hydrologic flow models and the radionuclide transport models. All the models and the repository design, in turn, will be incorporated into the Total System Performance Assessment (TSPA) of the potential radioactive waste repository block and vicinity to determine the suitability of Yucca Mountain as a host for the repository. The interrelationship of the three components of the ISM and their interface with downstream uses are illustrated in Figure 2.

R. Clayton

2000-12-19

103

Hierarchical control models for multimodal process modeling.  

PubMed

The multimodal and hierarchical structure characteristics of a system make process modeling quite difficult. In this paper, we present a hierarchical control model (HCM) for hierarchically multimodal processing. From multiple streams, a control layer extracts the inherent group process that denotes the evolution of the system and controls the evolution of every modality. HCMs model the influences of the group on modalities and represent the hierarchical structure of the system by a multilayer network. To estimate the state order of the model, we also present a new information criterion that corrects the preference of traditional criteria for more complex models and proves the rationality of HCMs. Comparisons with other models on multiagent activity recognition show that HCMs are reliable and efficient. PMID:19342349

Zhang, Weidong; Chen, Feng; Xu, Wenli

2009-10-01

104

ROCK PROPERTIES MODEL ANALYSIS MODEL REPORT  

SciTech Connect

The purpose of this Analysis and Model Report (AMR) is to document Rock Properties Model (RPM) 3.1 with regard to input data, model methods, assumptions, uncertainties and limitations of model results, and qualification status of the model. The report also documents the differences between the current and previous versions and validation of the model. The rock properties models are intended principally for use as input to numerical physical-process modeling, such as of ground-water flow and/or radionuclide transport. The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. This work was conducted in accordance with the following planning documents: WA-0344, ''3-D Rock Properties Modeling for FY 1998'' (SNL 1997, WA-0358), ''3-D Rock Properties Modeling for FY 1999'' (SNL 1999), and the technical development plan, Rock Properties Model Version 3.1, (CRWMS M&O 1999c). The Interim Change Notice (ICNs), ICN 02 and ICN 03, of this AMR were prepared as part of activities being conducted under the Technical Work Plan, TWP-NBS-GS-000003, ''Technical Work Plan for the Integrated Site Model, Process Model Report, Revision 01'' (CRWMS M&O 2000b). The purpose of ICN 03 is to record changes in data input status due to data qualification and verification activities. These work plans describe the scope, objectives, tasks, methodology, and implementing procedures for model construction. The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. The work scope for this activity consists of the following: (1) Conversion of the input data (laboratory measured porosity data, x-ray diffraction mineralogy, petrophysical calculations of bound water, and petrophysical calculations of porosity) for each borehole into stratigraphic coordinates; (2) Re-sampling and merging of data sets; (3) Development of geostatistical simulations of porosity; (4) Generation of derivative property models via linear coregionalization with porosity; (5) Post-processing of the simulated models to impart desired secondary geologic attributes and to create summary and uncertainty models; and (6) Conversion of the models into real-world coordinates. The conversion to real world coordinates is performed as part of the integration of the RPM into the Integrated Site Model (ISM) 3.1; this activity is not part of the current analysis. The ISM provides a consistent volumetric portrayal of the rock layers, rock properties, and mineralogy of the Yucca Mountain site and consists of three components: (1) Geologic Framework Model (GFM); (2) RPM, which is the subject of this AMR; and (3) Mineralogic Model. The interrelationship of the three components of the ISM and their interface with downstream uses are illustrated in Figure 1. Figure 2 shows the geographic boundaries of the RPM and other component models of the ISM.

Clinton Lum

2002-02-04

105

Strategic Thinking of Modeling Method and Modeling  

Microsoft Academic Search

Three-dimensional computer software have much to accomplish in the current application areas because they all have powerful modeling and simulation and recycling functions of real scenes. Today the most well-known and widely used 3D software should be 3DSMAX software, which is widely used in construction, decoration, video advertising and other areas. It offers us many modeling functions and various modeling

Guobin Peng; Runhong Peng

2010-01-01

106

Business Modelling Is Not Process Modelling  

Microsoft Academic Search

Innovative e-business projects start with a design of the e-business model. We often encounter the view, in research as well as industry practice, that an e-business model is similar to a business process model, and so can be specified using UML activity diagrams or Petri nets. In this paper, we explain why this is a misunderstanding. The root cause is

Jaap Gordijn; Hans Akkermans; Hans Van Vliet

2000-01-01

107

Network epistemology Discrete models  

E-print Network

Network epistemology Discrete models Continuous models Social Structure and Social Influence A study in network epistemology Kevin J.S. Zollman Social Dynamics Seminar Kevin J.S. Zollman Social Structure and Social Influence #12;Network epistemology Discrete models Continuous models Network

Zollman, Kevin

108

Relevance based language models  

Microsoft Academic Search

We explore the relation between classical probabilistic models of information retrieval and the emerging language modeling approaches. It has long been recognized that the primary obstacle to effective performance of classical models is the need to estimate arelevance model: probabilities of words in the relevant class. We propose a novel technique for estimating these probabilities using the query alone. We

Victor Lavrenko; W. Bruce Croft

2001-01-01

109

AIDS Epidemiological models  

NASA Astrophysics Data System (ADS)

The aim of this paper is to present mathematical modelling of the spread of infection in the context of the transmission of the human immunodeficiency virus (HIV) and the acquired immune deficiency syndrome (AIDS). These models are based in part on the models suggested in the field of th AIDS mathematical modelling as reported by ISHAM [6].

Rahmani, Fouad Lazhar

2010-11-01

110

Fire Model Matrix  

NSDL National Science Digital Library

The Fire Model Matrix is an on-line resource that presents four fire community models in a matrix that facilitates the exploration of the characteristics of each model. As part of the Advanced Fire Weather Forecasters Course, this matrix is meant to sensitize forecasters to the use of weather data in these fire models to forecast potential fire activity.

2014-09-14

111

Generative Models of Disfluency  

ERIC Educational Resources Information Center

This thesis describes a generative model for representing disfluent phenomena in human speech. This model makes use of observed syntactic structure present in disfluent speech, and uses a right-corner transform on syntax trees to model this structure in a very natural way. Specifically, the phenomenon of speech repair is modeled by explicitly…

Miller, Timothy A.

2010-01-01

112

New 3D model for dynamics modeling  

NASA Astrophysics Data System (ADS)

The wrist articulation represents one of the most complex mechanical systems of the human body. It is composed of eight bones rolling and sliding along their surface and along the faces of the five metacarpals of the hand and the two bones of the arm. The wrist dynamics are however fundamental for the hand movement, but it is so complex that it still remains incompletely explored. This work is a part of a new concept of computer-assisted surgery, which consists in developing computer models to perfect surgery acts by predicting their consequences. The modeling of the wrist dynamics are based first on the static model of its bones in three dimensions. This 3D model must optimise the collision detection procedure which is the necessary step to estimate the physical contact constraints. As many other possible computer vision models do not fit with enough precision to this problem, a new 3D model has been developed thanks to the median axis of the digital distance map of the bones reconstructed volume. The collision detection procedure is then simplified for contacts are detected between spheres. The experiment of this original 3D dynamic model products realistic computer animation images of solids in contact. It is now necessary to detect ligaments on digital medical images and to model them in order to complete a wrist model.

Perez, Alain

1994-05-01

113

Nearshore Wave Modeling  

NSDL National Science Digital Library

Ocean waves near shore impact public safety, commerce, navigation, and, of course recreation. Predicting these waves has driven efforts to model them for more than two decades. This module introduces forecasters to different nearshore wave models, including phase-resolving and 1- and 2-dimensional spectral models. It describes the processes that wave models simulate, the assumptions they make, the initial and boundary conditions required to run the models, and potential sources of error in model forecasts. While focusing on SWAN, the module also examines the Navy Standard surf Model and Bouss-2D.

Comet

2009-05-19

114

Calibrated Properties Model  

SciTech Connect

The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the AMR Development Plan for U0035 Calibrated Properties Model REV00 (CRWMS M&O 1999c). These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions.

C.F. Ahlers, H.H. Liu

2001-12-18

115

Calibrated Properties Model  

SciTech Connect

The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the ''AMR Development Plan for U0035 Calibrated Properties Model REV00. These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions.

C. Ahlers; H. Liu

2000-03-12

116

Gas Kick Mechanistic Model  

E-print Network

. The model is being simulated using Excel and Visual Basic for Applications (VBA). There are specific input Excel sheets through which the program creates profiles, simulated data and charts in specific output sheets. The calculations are performed in VBA... Santos model and mechanistic model ............................. 31 Fig. 16 - Comparison between Choe two phase model and mechanistic model .............. 31 vi LIST OF TABLES Page Table 1 – Input data for wellbore geometry, mud flow and bit...

Zubairy, Raheel

2014-04-18

117

Standard Information Models  

Microsoft Academic Search

In this chapter, the base Information Model of OPC UA is introduced. This model provides the foundation for OPC UA information\\u000a modeling and is always used as foundation to define additional Information Models. We will also look at the extensions of\\u000a this model defined by the OPC UA specification. Those extensions are used to define a standard way to represent

Wolfgang Mahnke; Stefan-Helmut Leitner

118

WASP TRANSPORT MODELING AND WASP ECOLOGICAL MODELING  

EPA Science Inventory

A combination of lectures, demonstrations, and hands-on excercises will be used to introduce pollutant transport modeling with the U.S. EPA's general water quality model, WASP (Water Quality Analysis Simulation Program). WASP features include a user-friendly Windows-based interfa...

119

Analytic Modeling Queuing Models with Single  

E-print Network

Analytic Modeling Queuing Models with Single Service Facility 1 Characteristics of a Service Facility · Number of servers · Queuing discipline ­ default is FCFS · Number of queuing spaces (or buffers ­ elapsed time from arrival to departure · Waiting time ­ time spent in queue · Number of customers

Shihada, Basem

120

Bohr model as an algebraic collective model  

Microsoft Academic Search

Developments and applications are presented of an algebraic version of Bohr's collective model. Illustrative examples show that fully converged calculations can be performed quickly and easily for a large range of Hamiltonians. As a result, the Bohr model becomes an effective tool in the analysis of experimental data. The examples are chosen both to confirm the reliability of the algebraic

D. J. Rowe; T. A. Welsh; M. A. Caprio

2009-01-01

121

MODELS AND HISTORY OF MODELING Hermann Schichl  

E-print Network

a mathematical model solar system with circles epicircles predict movement moon, and planets. The model accurate of mathematics independently application. Thales brought knowledge from Egypt, predicted solar eclipse philosophers Aristotle, Eudoxos, and many more added pieces, and years following Thales, geometry mathematics

Schichl, Hermann

122

1. Quark model 1 1. QUARK MODEL  

E-print Network

1. Quark model 1 1. QUARK MODEL Revised December 2005 by C. Amsler (University of Z¨urich), T. DeGrand (University of Colorado, Boulder) and B. Krusche (University of Basel). 1.1. Quantum numbers of the quarks Quarks are strongly interacting fermions with spin 1/2 and, by convention, positive parity

Krusche, Bernd

123

14. Quark model 1 14. QUARK MODEL  

E-print Network

14. Quark model 1 14. QUARK MODEL Revised August 2011 by C. Amsler (University of Z¨urich), T. DeGrand (University of Colorado, Boulder), and B. Krusche (University of Basel). 14.1. Quantum numbers of the quarks and its constituents are a set of fermions, the quarks, and gauge bosons, the gluons. Strongly interacting

124

14. Quark model 1 14. QUARK MODEL  

E-print Network

14. Quark model 1 14. QUARK MODEL Revised December 2005 by C. Amsler (University of Z¨urich), T. DeGrand (University of Colorado, Boulder) and B. Krusche (University of Basel). 14.1. Quantum numbers of the quarks Quarks are strongly interacting fermions with spin 1/2 and, by convention, positive parity

Krusche, Bernd

125

14. Quark model 1 14. QUARK MODEL  

E-print Network

14. Quark model 1 14. QUARK MODEL Revised September 2009 by C. Amsler (University of Z¨urich), T numbers of the quarks Quarks are strongly interacting fermions with spin 1/2 and, by convention, positive parity. Antiquarks have negative parity. Quarks have the additive baryon number 1/3, antiquarks -1

126

Business Model Innovation: A Process Model  

Microsoft Academic Search

What is business model innovation? A business model is much more than a description of a particular product or service. In addition to describing the offering itself, it lays out the value proposition behind it (i.e., how it creates value for a defined set of customers). It also describes the capabilities and resources needed to execute that value proposition and

Jeanne Liedtka

127

Models and their benefits. Models + Data  

E-print Network

of individual histories 3. hypothesis testing 4. parameter estimation #12;Haploid Model Diploid Model Wright;10 Alleles'Ancestry for 15 generations #12;Mean, E(X2) = 2N. Ex.: 2N = 20.000, Generation time 30 years, E(X2

Goldschmidt, Christina

128

What is a model? Mathematical modelling Examples Conclusions What is Mathematical Modelling?  

E-print Network

What is a model? Mathematical modelling Examples Conclusions What is Mathematical Modelling? John 21, 2014 What is a Model? 1/33 #12;What is a model? Mathematical modelling Examples Conclusions Outline 1 What is a model? Disciplinary differences 2 Mathematical modelling Definition Quotes Modelling

Stockie, John

129

jModelTest: phylogenetic model averaging.  

PubMed

jModelTest is a new program for the statistical selection of models of nucleotide substitution based on "Phyml" (Guindon and Gascuel 2003. A simple, fast, and accurate algorithm to estimate large phylogenies by maximum likelihood. Syst Biol. 52:696-704.). It implements 5 different selection strategies, including "hierarchical and dynamical likelihood ratio tests," the "Akaike information criterion," the "Bayesian information criterion," and a "decision-theoretic performance-based" approach. This program also calculates the relative importance and model-averaged estimates of substitution parameters, including a model-averaged estimate of the phylogeny. jModelTest is written in Java and runs under Mac OSX, Windows, and Unix systems with a Java Runtime Environment installed. The program, including documentation, can be freely downloaded from the software section at http://darwin.uvigo.es. PMID:18397919

Posada, David

2008-07-01

130

Trapped Radiation Model Uncertainties: Model-Data and Model-Model Comparisons  

NASA Astrophysics Data System (ADS)

The standard AP8 and AE8 models for predicting trapped proton and electron environments have been compared with several sets of flight data to evaluate model uncertainties. Model comparisons are made with flux and dose measurements made on various U.S. low-Earth orbit satellites (APEX, CRRES, DMSP, LDEF, NOAA) and Space Shuttle flights, on Russian satellites (Photon-8, Cosmos-1887, Cosmos-2044), and on the Russian Mir Space Station. This report gives the details of the model-data comparisons-summary results in terms of empirical model uncertainty factors that can be applied for spacecraft design applications are given in a combination report. The results of model-model comparisons are also presented from standard AP8 and AE8 model predictions compared with the European Space Agency versions of AP8 and AE8 and with Russian-trapped radiation models.

Armstrong, T. W.; Colborn, B. L.

2000-03-01

131

Trapped Radiation Model Uncertainties: Model-Data and Model-Model Comparisons  

NASA Astrophysics Data System (ADS)

The standard AP8 and AE8 models for predicting trapped proton and electron environments have been compared with several sets of flight data to evaluate model uncertainties. Model comparisons are made with flux and dose measurements made on various U.S. low-Earth orbit satellites (APEX, CRRES, DMSP. LDEF, NOAA) and Space Shuttle flights, on Russian satellites (Photon-8, Cosmos-1887, Cosmos-2044), and on the Russian Mir space station. This report gives the details of the model-data comparisons -- summary results in terms of empirical model uncertainty factors that can be applied for spacecraft design applications are given in a companion report. The results of model-model comparisons are also presented from standard AP8 and AE8 model predictions compared with the European Space Agency versions of AP8 and AE8 and with Russian trapped radiation models.

Armstrong, T. W.; Colborn, B. L.

2000-02-01

132

Trapped Radiation Model Uncertainties: Model-Data and Model-Model Comparisons  

NASA Technical Reports Server (NTRS)

The standard AP8 and AE8 models for predicting trapped proton and electron environments have been compared with several sets of flight data to evaluate model uncertainties. Model comparisons are made with flux and dose measurements made on various U.S. low-Earth orbit satellites (APEX, CRRES, DMSP, LDEF, NOAA) and Space Shuttle flights, on Russian satellites (Photon-8, Cosmos-1887, Cosmos-2044), and on the Russian Mir Space Station. This report gives the details of the model-data comparisons-summary results in terms of empirical model uncertainty factors that can be applied for spacecraft design applications are given in a combination report. The results of model-model comparisons are also presented from standard AP8 and AE8 model predictions compared with the European Space Agency versions of AP8 and AE8 and with Russian-trapped radiation models.

Armstrong, T. W.; Colborn, B. L.

2000-01-01

133

Pharmacokinetics: philosophy of modeling.  

PubMed

Generally speaking, there are two extremes of scientific personality types: sharpeners and levelers. Sharpeners, highly attuned to system differences and nuances, and always alert to distinctions, try hard to let nothing slip by them unnoticed. Levelers, on the other hand, attempt to submerge system differences, reveal uniform patterns, and condense disparate elements. This paper is one leveler's attempt to address the following philosophical questions confronting pharmacokinetic modelers: (1) What is the nature of reality? (2) What is a model? (3) Why do we model? (4) What are the different types of models? (5) How do we model? (6) What are the properties and characteristics of models? (7) How do we evaluate models? (8) What are some of the tricks and traps of modeling? And (9), what are some of the psychological characteristics of modelers? PMID:1555495

Boxenbaum, H

1992-01-01

134

Practical Marginalized Multilevel Models.  

PubMed

Clustered data analysis is characterized by the need to describe both systematic variation in a mean model and cluster-dependent random variation in an association model. Marginalized multilevel models embrace the robustness and interpretations of a marginal mean model, while retaining the likelihood inference capabilities and flexible dependence structures of a conditional association model. Although there has been increasing recognition of the attractiveness of marginalized multilevel models, there has been a gap in their practical application arising from a lack of readily available estimation procedures. We extend the marginalized multilevel model to allow for nonlinear functions in both the mean and association aspects. We then formulate marginal models through conditional specifications to facilitate estimation with mixed model computational solutions already in place. We illustrate the MMM and approximate MMM approaches on a cerebrovascular deficiency crossover trial using SAS and an epidemiological study on race and visual impairment using R. Datasets, SAS and R code are included as supplemental materials. PMID:24357884

Griswold, Michael E; Swihart, Bruce J; Caffo, Brian S; Zeger, Scott L

2013-01-01

135

All models are wrong.  

PubMed

As the field of phylogeography has continued to move in the model-based direction, researchers continue struggling to construct useful models for inference. These models must be both simple enough to be tractable yet contain enough of the complexity of the natural world to make meaningful inference. Beyond constructing such models for inference, researchers explore model space and test competing models with the data on hand, with the goal of improving the understanding of the natural world and the processes underlying natural biological communities. Approximate Bayesian computation (ABC) has increased in recent popularity as a tool for evaluating alternative historical demographic models given population genetic samples. As a thorough demonstration, Pelletier & Carstens (2014) use ABC to test 143 phylogeographic submodels given geographically widespread genetic samples from the salamander species Plethodon idahoensis (Carstens et al. 2014) and, in so doing, demonstrate how the results of the ABC model choice procedure are dependent on the model set one chooses to evaluate. PMID:24931159

Hickerson, Michael J

2014-06-01

136

Marine Modeling and Analysis  

NSDL National Science Digital Library

The Marine Modeling and Analysis Branch (MMAB) of the Environmental Modeling Center is responsible for the development of improved numerical weather and marine prediction modeling systems. These models provide analysis and real-time forecast guidance on marine meteorological, oceanographic, and cryospheric parameters over the global oceans and coastal areas of the US. This site provides access to MMAB modeling tools for ocean waves (including an interactive presentation,) sea ice, marine meteorology, sea surface temperature and more. The site also features a mailing list, bibliography of publications, and information about modeling products still in the experimental and development phases.

National Centers For Environmental Prediction, National O.

137

Reliability model generator  

NASA Technical Reports Server (NTRS)

An improved method and system for automatically generating reliability models for use with a reliability evaluation tool is described. The reliability model generator of the present invention includes means for storing a plurality of low level reliability models which represent the reliability characteristics for low level system components. In addition, the present invention includes means for defining the interconnection of the low level reliability models via a system architecture description. In accordance with the principles of the present invention, a reliability model for the entire system is automatically generated by aggregating the low level reliability models based on the system architecture description.

McMann, Catherine M. (Inventor); Cohen, Gerald C. (Inventor)

1991-01-01

138

The Dgp Model Revisited  

NASA Astrophysics Data System (ADS)

In this paper, we study the model proposed by Dvali, Gabadadze and Porrati (the DGP model), which produces solutions with cosmic acceleration even in the absence of a cosmological constant. The model is fitted to the recent SNLS data using the minimum ?2 test, and an analytical method is used to marginalize over the nuisance parameters h and M. The result suggests that the DPG model does not fit the SNLS data much better than the ?CDM model, and further observations are needed to better distinguish the two models.

Ng, Kah Fee; Ng, Shao Chin Cindy

2014-04-01

139

Inflation models and observation  

E-print Network

We consider small-field models which invoke the usual framework for the effective field theory, and large-field models which go beyond that. Present and future possibilities for discriminating between the models are assessed, on the assumption that the primordial curvature perturbation is generated during inflation. With PLANCK data, the theoretical and observational uncertainties on the spectral index will be comparable, providing useful discrimination between small-field models. Further discrimination between models may come later through the tensor fraction, the running of the spectral index and non-gaussianity. The prediction for the trispectrum in a generic multi-field inflation model is given for the first time.

Laila Alabidi; David Lyth

2005-12-01

140

Energy-consumption modelling  

SciTech Connect

A highly sophisticated and accurate approach is described to compute on an hourly or daily basis the energy consumption for space heating by individual buildings, urban sectors, and whole cities. The need for models and specifically weather-sensitive models, composite models, and space-heating models are discussed. Development of the Colorado State University Model, based on heat-transfer equations and on a heuristic, adaptive, self-organizing computation learning approach, is described. Results of modeling energy consumption by the city of Minneapolis and Cheyenne are given. Some data on energy consumption in individual buildings are included.

Reiter, E.R.

1980-01-01

141

Modeling volatility using state space models.  

PubMed

In time series problems, noise can be divided into two categories: dynamic noise which drives the process, and observational noise which is added in the measurement process, but does not influence future values of the system. In this framework, we show that empirical volatilities (the squared relative returns of prices) exhibit a significant amount of observational noise. To model and predict their time evolution adequately, we estimate state space models that explicitly include observational noise. We obtain relaxation times for shocks in the logarithm of volatility ranging from three weeks (for foreign exchange) to three to five months (for stock indices). In most cases, a two-dimensional hidden state is required to yield residuals that are consistent with white noise. We compare these results with ordinary autoregressive models (without a hidden state) and find that autoregressive models underestimate the relaxation times by about two orders of magnitude since they do not distinguish between observational and dynamic noise. This new interpretation of the dynamics of volatility in terms of relaxators in a state space model carries over to stochastic volatility models and to GARCH models, and is useful for several problems in finance, including risk management and the pricing of derivative securities. Data sets used: Olsen & Associates high frequency DEM/USD foreign exchange rates (8 years). Nikkei 225 index (40 years). Dow Jones Industrial Average (25 years). PMID:9730016

Timmer, J; Weigend, A S

1997-08-01

142

Reducing Model Systematic Error through Super Modelling  

NASA Astrophysics Data System (ADS)

Numerical models are key tools in the projection of the future climate change. However, state-of-the-art general circulation models (GCMs) exhibit significant systematic errors and large uncertainty exists in future climate projections, because of limitations in parameterization schemes and numerical formulations. The general approach to tackle uncertainty is to use an ensemble of several different GCMs. However, ensemble results may smear out major variability, such as the ENSO. Here we take a novel approach and build a super model (i.e., an optimal combination of several models): We coupled two atmospheric GCMs (AGCM) with one ocean GCM (OGCM). The two AGCMs receive identical boundary conditions from the OGCM, while the OGCM is driven by a weighted flux combination from the AGCMs. The atmospheric models differed in their convection scheme and climate-related parameters. As climate models show large sensitivity to convection schemes and parameterization, this approach may be a good basis for constructing a super model. We performed experiments with a small set of manually chosen coefficients and also with a learning algorithm to adjust the coefficients. The coupling strategy is able to synchronize atmospheric variability of the two AGCMs in the tropics, particularly over the western equatorial Pacific, and produce reasonable climate variability. Different coupling weights were shown to alter the simulated mean climate state. Some improvements were found that suggest a refined strategy for choosing weighting coefficients could lead to even better performance.

Shen, Mao-Lin; Keenlyside, Noel; Selten, Frank; Duane, Gregory; Wiegerinck, Wim; Hiemstra, Paul

2013-04-01

143

Develop a Model Component  

NASA Technical Reports Server (NTRS)

During my internship at NASA, I was a model developer for Ground Support Equipment (GSE). The purpose of a model developer is to develop and unit test model component libraries (fluid, electrical, gas, etc.). The models are designed to simulate software for GSE (Ground Special Power, Crew Access Arm, Cryo, Fire and Leak Detection System, Environmental Control System (ECS), etc. .) before they are implemented into hardware. These models support verifying local control and remote software for End-Item Software Under Test (SUT). The model simulates the physical behavior (function, state, limits and 110) of each end-item and it's dependencies as defined in the Subsystem Interface Table, Software Requirements & Design Specification (SRDS), Ground Integrated Schematic (GIS), and System Mechanical Schematic.(SMS). The software of each specific model component is simulated through MATLAB's Simulink program. The intensiv model development life cycle is a.s follows: Identify source documents; identify model scope; update schedule; preliminary design review; develop model requirements; update model.. scope; update schedule; detailed design review; create/modify library component; implement library components reference; implement subsystem components; develop a test script; run the test script; develop users guide; send model out for peer review; the model is sent out for verifictionlvalidation; if there is empirical data, a validation data package is generated; if there is not empirical data, a verification package is generated; the test results are then reviewed; and finally, the user. requests accreditation, and a statement of accreditation is prepared. Once each component model is reviewed and approved, they are intertwined together into one integrated model. This integrated model is then tested itself, through a test script and autotest, so that it can be concluded that all models work conjointly, for a single purpose. The component I was assigned, specifically, was a fluid component, a discrete pressure switch. The switch takes a fluid pressure input, and if the pressure is greater than a designated cutoff pressure, the switch would stop fluid flow.

Ensey, Tyler S.

2013-01-01

144

Volumetric particle modeling  

E-print Network

This dissertation presents a robust method of modeling objects and forces for computer animation. Within this method objects and forces are represented as particles. As in most modeling systems, the movement of objects is driven by physically based...

Dingle, Brent Michael

2007-09-17

145

Monte Carlo Modeling  

NSDL National Science Digital Library

Monte Carlo modeling refers to the solution of mathematical problems with the use of random numbers. This can include both function integration and the modeling of stochastic phenomena using random processes.

David Joiner

146

X-33 RCS model  

NASA Technical Reports Server (NTRS)

Model support system and instumentation cabling of the 1% scale X-33 reaction control system model. Installed in the Unitary Plan Wind Tunnel for supersonic testing. In building 1251, test section #2.

1998-01-01

147

Communication system modeling  

NASA Technical Reports Server (NTRS)

This report presents the results of work on communications systems modeling and covers three different areas of modeling. The first of these deals with the modeling of signals in communication systems in the frequency domain and the calculation of spectra for various modulations. These techniques are applied in determining the frequency spectra produced by a unified carrier system, the down-link portion of the Command and Communications System (CCS). The second modeling area covers the modeling of portions of a communication system on a block basis. A detailed analysis and modeling effort based on control theory is presented along with its application to modeling of the automatic frequency control system of an FM transmitter. A third topic discussed is a method for approximate modeling of stiff systems using state variable techniques.

Holland, L. D.; Walsh, J. R., Jr.; Wetherington, R. D.

1971-01-01

148

SEDIMENT GEOCHEMICAL MODEL  

EPA Science Inventory

Until recently, sediment geochemical models (diagenetic models) have been only able to explain sedimentary flux and concentration profiles for a few simplified geochemical cycles (e.g., nitrogen, carbon and sulfur). However with advances in numerical methods, increased accuracy ...

149

Modeling Instruction Program  

NSDL National Science Digital Library

Arizona State University's modeling instruction and software development research. This approach to reform of curriculum design and teaching methodology has been guided by a Modeling Theory of Physics Instruction.

Hestenes, David

2003-10-10

150

Content models with attitude  

E-print Network

We present a probabilistic topic model for jointly identifying properties and attributes of social media review snippets. Our model simultaneously learns a set of properties of a product and captures aggregate user sentiments ...

Sauper, Christina Joan

151

TMDL RUSLE MODEL  

EPA Science Inventory

We developed a simplified spreadsheet modeling approach for characterizing and prioritizing sources of sediment loadings from watersheds in the United States. A simplified modeling approach was developed to evaluate sediment loadings from watersheds and selected land segments. ...

152

Bounding Species Distribution Models  

NASA Technical Reports Server (NTRS)

Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

2011-01-01

153

Supersymmetry and model building  

SciTech Connect

An introductory review of supersymmetry and supersymmetric model building is presented. The topics discussed include, a brief introduction to the formalism of supersymmetry, the gauge hierarchy problem, the minimal supersymmetric standard model and supersymmetric grand unified theories.

Raby, S.

1986-06-01

154

Protein solubility modeling  

NASA Technical Reports Server (NTRS)

A thermodynamic framework (UNIQUAC model with temperature dependent parameters) is applied to model the salt-induced protein crystallization equilibrium, i.e., protein solubility. The framework introduces a term for the solubility product describing protein transfer between the liquid and solid phase and a term for the solution behavior describing deviation from ideal solution. Protein solubility is modeled as a function of salt concentration and temperature for a four-component system consisting of a protein, pseudo solvent (water and buffer), cation, and anion (salt). Two different systems, lysozyme with sodium chloride and concanavalin A with ammonium sulfate, are investigated. Comparison of the modeled and experimental protein solubility data results in an average root mean square deviation of 5.8%, demonstrating that the model closely follows the experimental behavior. Model calculations and model parameters are reviewed to examine the model and protein crystallization process. Copyright 1999 John Wiley & Sons, Inc.

Agena, S. M.; Pusey, M. L.; Bogle, I. D.

1999-01-01

155

How Mesoscale Models Work  

NSDL National Science Digital Library

The goal of this training module is to help you increase your understanding of how mesoscale models work. Such understanding, in turn, can help you more efficiently and accurately evaluate model-generated forecast products.

COMET

2002-04-22

156

Visualization of Model Output  

NSDL National Science Digital Library

Visualization of output from mathematical or statistical models is one of the best ways to introduce introductory geoscience students to the results and behavior of sophisticated models. Example of good sites ...

157

Of Molecules and Models.  

ERIC Educational Resources Information Center

Presents an activity in which models help students visualize both the DNA process and transcription. After constructing DNA, RNA messenger, and RNA transfer molecules; students model cells, protein synthesis, codons, and RNA movement. (MDH)

Brinner, Bonnie

1992-01-01

158

Melanoma Risk Prediction Models  

Cancer.gov

The following risk prediction models are intended primarily for research use and have been peer-reviewed, meaning the methodology and results of these models have been evaluated by qualified scientists and clinicians and published in scientific and medical journals.

159

Exposure Analysis Modeling System  

EPA Science Inventory

The Exposure Analysis Modeling System (EXAMS) is an interactive software application for formulating aquatic ecosystem models and evaluating the fate, transport, and exposure concentrations of synthetic organic chemicals including pesticides, industrial materials, and leachates f...

160

Modeling Thermospheric Neutral Density.  

E-print Network

??Satellite drag prediction requires determination of thermospheric neutral density. The NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) and the global-mean Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIMEGCM) were… (more)

Qian, Liying

2007-01-01

161

ISIS Camera Model Design  

NASA Astrophysics Data System (ADS)

The Integrated Software for Imagers and Spectromters (ISIS) provides camera model support for a variety of past and current NASA missions. Adding new camera models to ISIS has become easier due to object-oriented design.

Anderson, J. A.

2008-03-01

162

Osteoporotic fracture models.  

PubMed

Animal models are widely used to investigate the pathogenesis of osteoporosis and for the clinical testing of anti-resorptive drugs. However, osteoporotic fracture models designed to investigate novel ways to treat fractures of osteoporotic bone must fulfil requirements distinct from those of pharmacological testing. Bone strength and toughness, implant fixation and osteointegration and fracture repair are of particular interest. Osteoporotic models should reflect the underlying clinical scenario be that primary type 1 (post-menopausal) osteoporosis, primary type 2 (senile) osteoporosis or secondary osteoporosis. In each scenario, small and large animal models have been developed. While rodent models facilitate the study of fractures in strains specifically established to facilitate understanding of the pathologic basis of disease, concerns remain about the relevance of small animal fracture models to the human situation. There is currently no all-encompassing model, and the choice of species and model must be individualized to the scientific question being addressed. PMID:25388154

Simpson, A Hamish; Murray, Iain R

2015-02-01

163

The Model Builders  

NASA Technical Reports Server (NTRS)

This video explores the world of modeling at the NASA Johnson Space Center. Artisans create models, large and small, to help scientists and engineers make final design modifications before building more costly prototypes.

1991-01-01

164

METEOROLOGICAL AND TRANSPORT MODELING  

EPA Science Inventory

Advanced air quality simulation models, such as CMAQ, as well as other transport and dispersion models, require accurate and detailed meteorology fields. These meteorology fields include primary 3-dimensional dynamical and thermodynamical variables (e.g., winds, temperature, mo...

165

Faraday Loop Model  

NSDL National Science Digital Library

The EJS Faraday Loop Model shows a conducting loop in a time-dependent constant magnetic field. The model is initially incomplete and students must complete the model by adding the appropriate equations. If Ejs is installed, right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item allows for editing of the model. The Faraday Loop model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_em_FaradayLoop.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Cox, Anne

2009-06-26

166

MODELING EARTHQUAKE DYNAMICS  

E-print Network

Abstract. In this paper, we investigate questions arising in [89]. Pseudo causal models connecting magnitudes and waiting times are consider, through generalized regression. We do use conditional model (magnitude given previous waiting time,

Arthur Charpentier; Marilou Durand; Mathieu Boudreault; A. Charpentier; M. Durand; M. Boudreault

2013-01-01

167

Generalized Additive Models  

Microsoft Academic Search

Likelihood-based regression models such as the normal linear regression model and the linear logistic model, assume a linear (or some other parametric) form for the covariates $X_1, X_2, \\\\cdots, X_p$. We introduce the class of generalized additive models which replaces the linear form $\\\\sum \\\\beta_jX_j$ by a sum of smooth functions $\\\\sum s_j(X_j)$. The $s_j(\\\\cdot)$'s are unspecified functions that are

Trevor Hastie; Robert Tibshirani

1986-01-01

168

Introduction to Ocean Models  

NSDL National Science Digital Library

Oceans cover over 70% of the surface of the earth, yet many details of their workings are not fully understood. To better understand and forecast the state of the ocean, we rely on numerical ocean models. Ocean models combine observations and physics to predict the ocean temperature, salinity, and currents at any time and any place across the ocean basins. This module will discuss what goes into numerical ocean models, including model physics, coordinate systems, parameterization, initialization, and boundary conditions.

Comet

2007-08-06

169

State-Space Models  

Microsoft Academic Search

\\u000a A very general model that seems to subsume a whole class of special cases of interest in much the same way that linear regression\\u000a does is the state-space model or the dynamic linear model, which was introduced in Kalman (1960) and Kalman and Bucy (1961).\\u000a Although the model was originally introduced as a method primarily for use in aerospace-related research,

Robert H. Shumway; David S. Stoffer

170

Interconnected air spring model  

Microsoft Academic Search

This article considers the mathematical modelling of the spring force of three interconnected rolling diaphragm type air springs used on a 40-ton tri-axle semi-trailer. The aim of the air spring model is to obtain a validated mathematical model that can be used in full vehicle multi-body dynamic simulations. The model considers the flow effects in the pipes connecting the three

Cor-Jacques Kat; Pieter Schalk Els

2009-01-01

171

Aerosol Modeling for the Global Model Initiative  

NASA Technical Reports Server (NTRS)

The goal of this project is to develop an aerosol module to be used within the framework of the Global Modeling Initiative (GMI). The model development work will be preformed jointly by the University of Michigan and AER, using existing aerosol models at the two institutions as starting points. The GMI aerosol model will be tested, evaluated against observations, and then applied to assessment of the effects of aircraft sulfur emissions as needed by the NASA Subsonic Assessment in 2001. The work includes the following tasks: 1. Implementation of the sulfur cycle within GMI, including sources, sinks, and aqueous conversion of sulfur. Aerosol modules will be added as they are developed and the GMI schedule permits. 2. Addition of aerosol types other than sulfate particles, including dust, soot, organic carbon, and black carbon. 3. Development of new and more efficient parameterizations for treating sulfate aerosol nucleation, condensation, and coagulation among different particle sizes and types.

Weisenstein, Debra K.; Ko, Malcolm K. W.

2001-01-01

172

3 Human vs. model 2 Salience model  

E-print Network

4 Contour model Robert J. Peters (1), T. Nathan Mundhenk (2), Laurent Itti (2), and Christof Koch (1 Winner-take-all Inhibition of return Attended location adapted from Itti&Koch (2001), Nat. Rev. Neurosci

Peters, Rob

173

Sources of Model Error  

NSDL National Science Digital Library

This undergraduate meteorology tutorial from Texas A&M University describes the common sources of weather forecasting computer model error, ways to identify model error, and how to correct a forecast for some simple types of error. Model sensitivity to parameterization and topography are covered.

Nielsen-Gammon, John

1996-01-01

174

Generic sonar Model  

Microsoft Academic Search

The Generic Sonar Model is a computer program designed to provide sonar system developers with a comprehensive modeling capability for evaluating the performance of sonar systems and investigating the ocean environment in which they operate. The model provides features not presently available in any single computer program. These permit cost\\/accuracy trade-offs for specific applications, and interfacing the results with generalized

H. Weinberg

1982-01-01

175

Lightning Return Stroke Models  

Microsoft Academic Search

We test the two most commonly used lightning return stroke models, Bruce-Golde and trammission line, against subsequent stroke electric and magnetic field wave forms measured simultaneously at near and distant stations and show that these models are inadequate to describe the experimental data. We then propose a new return stroke model that is physically plausible and that yields good approximations

Y. T. Lin; M. A. Uman; R. B. Standler

1980-01-01

176

Bioeconomic and market models  

Microsoft Academic Search

5 Abstract: The United States has a century of experience with the development of models that describe markets for forest products and trends in resource conditions. In the last four decades, increasing rigor in policy debates has stimulated the development of models to support policy analysis. Increasingly, research has evolved (often relying on computer-based models) to increase understanding of consumer

Richard Haynes; Darius Adams; Peter Ince; John Mills; Ralph Alig

177

An Eddifying Parsons Model  

E-print Network

The time-mean effects of eddies are studied in a model based on the Parsons–Veronis–Huang–Flierl models of the wind-driven gyre. Much of the analysis used for the steady solutions carries over if the model is cast in terms ...

Ferrari, Raffaele

178

Phenomenological models of baryon  

E-print Network

In this paper, I present almost my works performed during my time at VNU. I was interested in the composite Skyrme model proposed by H. Y. Cheung and F. Gursey. The expanding for this model based on results obtained from the original Skyrme model given by T. H. R. Skyrme in 1961 was general and interesting.

Do Quoc Tuan

2008-07-12

179

A Model Chemistry Class.  

ERIC Educational Resources Information Center

Described is an activity which uses a 96-well reaction plate and soda straws to construct a model of the periodic table of the elements. The model illustrates the ionization energies of the various elements. Construction of the model and related concepts are discussed. (CW)

Summerlin, Lee; Borgford, Christie

1989-01-01

180

Bicycles, motorcycles, and models  

Microsoft Academic Search

The development of bicycles and motorcycles since the first patented running machine, or draisine, in 1817 is described. Bicycle modeling and control were also discussed. These models include: derivatives or simplifications of Whipple's bicycle dynamics model in which the lateral motion constraints at the road contact are nonholonomic, requiring special techniques to form correct equations of motion; and the Timoshenko-Young

DAVID J. N. LIMEBEER; ROBIN S. SHARP

2006-01-01

181

The Constructivist Learning Model  

NSDL National Science Digital Library

Much cognitive science research has been used to support a new model of learning. This most promising new model is called the Constructivist Learning Model (CLM). Russell Yeany (University of Georgia) has called CLM the most exciting idea of the past 50 y

Robert E. Yager

2000-01-01

182

HETEROGENEOUS MODELING AND  

E-print Network

PTOLEMY II HETEROGENEOUS CONCURRENT MODELING AND DESIGN IN JAVA Edited by: Christopher Hylands of California at Berkeley http://ptolemy.eecs.berkeley.edu Document Version 2.0.1 for use with Ptolemy II 2 Concurrent Modeling and Design Contents Part 1: Using Ptolemy II 1. Introduction 1-1 1.1.Modeling and Design

183

Reasoning and Formal Modelling  

E-print Network

Reasoning and Formal Modelling for Forensic Science Lecture 10 Prof. Dr. Benedikt L¨owe Reasoning and Formal Modelling for Forensic Science Lecture 10 Prof. Dr. Benedikt L¨owe 2nd Semester 2010/11 #12;Reasoning and Formal Modelling for Forensic Science Lecture 10 Prof. Dr. Benedikt L¨owe A reminder from

Löwe, Benedikt

184

Reasoning and Formal Modelling  

E-print Network

Reasoning and Formal Modelling for Forensic Science Lecture 6 Prof. Dr. Benedikt L¨owe Reasoning and Formal Modelling for Forensic Science Lecture 6 Prof. Dr. Benedikt L¨owe 2nd Semester 2010/11 #12;Reasoning and Formal Modelling for Forensic Science Lecture 6 Prof. Dr. Benedikt L¨owe Reminder: Controlled

Löwe, Benedikt

185

Reasoning and Formal Modelling  

E-print Network

Reasoning and Formal Modelling for Forensic Science Lecture 5 Prof. Dr. Benedikt L¨owe Reasoning and Formal Modelling for Forensic Science Lecture 5 Prof. Dr. Benedikt L¨owe 2nd Semester 2010/11 #12;Reasoning and Formal Modelling for Forensic Science Lecture 5 Prof. Dr. Benedikt L¨owe Reminder: Controlled

Löwe, Benedikt

186

Reasoning and Formal Modelling  

E-print Network

Reasoning and Formal Modelling for Forensic Science Lecture 12 Prof. Dr. Benedikt L¨owe Reasoning and Formal Modelling for Forensic Science Lecture 12 Prof. Dr. Benedikt L¨owe 2nd Semester 2010/11 #12;Reasoning and Formal Modelling for Forensic Science Lecture 12 Prof. Dr. Benedikt L¨owe Plan for today. #12

Löwe, Benedikt

187

Reasoning and Formal Modelling  

E-print Network

Reasoning and Formal Modelling for Forensic Science Lecture 9 Prof. Dr. Benedikt L¨owe Reasoning and Formal Modelling for Forensic Science Lecture 9 Prof. Dr. Benedikt L¨owe 2nd Semester 2010/11 #12;Reasoning and Formal Modelling for Forensic Science Lecture 9 Prof. Dr. Benedikt L¨owe Argumentation Schemes

Löwe, Benedikt

188

Reasoning and Formal Modelling  

E-print Network

Reasoning and Formal Modelling for Forensic Science Lecture 4 Prof. Dr. Benedikt L¨owe Reasoning and Formal Modelling for Forensic Science Lecture 4 Prof. Dr. Benedikt L¨owe 2nd Semester 2010/11 #12;Reasoning and Formal Modelling for Forensic Science Lecture 4 Prof. Dr. Benedikt L¨owe Where are we right

Löwe, Benedikt

189

Reasoning and Formal Modelling  

E-print Network

Reasoning and Formal Modelling for Forensic Science Lecture 7 Prof. Dr. Benedikt L¨owe Reasoning and Formal Modelling for Forensic Science Lecture 7 Prof. Dr. Benedikt L¨owe 2nd Semester 2010/11 #12;Reasoning and Formal Modelling for Forensic Science Lecture 7 Prof. Dr. Benedikt L¨owe Reminder: logica

Löwe, Benedikt

190

Reasoning and Formal Modelling  

E-print Network

Reasoning and Formal Modelling for Forensic Science Lecture 3 Prof. Dr. Benedikt L¨owe Reasoning and Formal Modelling for Forensic Science Lecture 3 Prof. Dr. Benedikt L¨owe 2nd Semester 2010/11 #12;Reasoning and Formal Modelling for Forensic Science Lecture 3 Prof. Dr. Benedikt L¨owe Binary connectives

Löwe, Benedikt

191

IR DIAL performance modeling  

SciTech Connect

We are developing a DIAL performance model for CALIOPE at LLNL. The intent of the model is to provide quick and interactive parameter sensitivity calculations with immediate graphical output. A brief overview of the features of the performance model is given, along with an example of performance calculations for a non-CALIOPE application.

Sharlemann, E.T.

1994-07-01

192

Modeling the calcite Lysocline  

Microsoft Academic Search

A numerical model of calcite dissolution in contact with sediment pore water is used to predict the depth and shape of the calcite lysocline in the deep sea. Model results are compared with lysocline data from 13 regions in the Atlantic, Pacific, and Indian Oceans. The model lysocline shape is sensitive to the calcite dissolution rate constant, the calcite, organic

David Archer

1991-01-01

193

Crushed Salt Constitutive Model  

SciTech Connect

The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the model -- one for the shear consolidation tests and one for a combination of the shear and hydrostatic consolidation tests. Using the parameter values determined from the fitted database, the constitutive model is validated against constant strain-rate tests. Shaft seal problems are analyzed to demonstrate model-predicted consolidation of the shaft seal crushed-salt component. Based on the fitting statistics, the ability of the model to predict the test data, and the ability of the model to predict load paths and test data outside of the fitted database, the model appears to capture the creep consolidation behavior of crushed salt reasonably well.

Callahan, G.D.

1999-02-01

194

'Rational' Turbulence Models?  

NASA Astrophysics Data System (ADS)

A procedure to construct turbulence models is outlined beginning with the simplest case, a model for weak time-dependent perturbations of homogeneous isotropic turbulence, and ending with some models for inhomogeneous turbulence. The approach combines features of Yoshizawa's two-scale direct interaction approximation and the Hilbert expansion of kinetic theory.

Rubinstein, Robert; Woodruff, Stephen L.

195

Global Timber Model (GTM)  

EPA Science Inventory

GTM is an economic model capable of examining global forestry land-use, management, and trade responses to policies. In responding to a policy, the model captures afforestation, forest management, and avoided deforestation behavior. The model estimates harvests in industrial fore...

196

Modeling Hybrid Genetic Algorithms  

Microsoft Academic Search

This paper looks at how one form of hybrid genetic algorithm can be modeledin the context of the existing models for the simple genetic algorithm; it shouldbe possible to model the integration of other types of local search with geneticalgorithms using the same basic approach. A secondary goal of this paper is toreview the existing models for finite and infinite

Darrell Whitley

1995-01-01

197

Tests of Rating Models  

ERIC Educational Resources Information Center

The study reports empirical tests of Anderson's, Haubensak's, Helson's, and Parducci's rating models when two end anchors are used for rating. The results show that these models cannot predict the judgment effect called here the Dai Pra effect. It is shown that an extension of Anderson's model is consistent with this effect. The results confirm…

Masin, Sergio Cesare; Busetto, Martina

2010-01-01

198

The Model Neuron  

NSDL National Science Digital Library

In this activity, learners create a model of a neuron by using colored clay or play dough. Learners use diagrams to build the model and then label the parts on a piece of paper. This resource guide includes extension ideas like using fruit or candy instead of clay. See the "Modeling the Nervous System" page for a recipe for play dough.

2012-06-26

199

New Dual Quark Models  

Microsoft Academic Search

On the basis of new representations of the projective group, we construct some new dual quark models whose spin and internal symmetry are not multiplicative. One model is a factorized theory of exotic states with broken exchange degeneracy, ninth mesons being optional. The exotic states are suppressed three units below the Pomeranchon. In another model, with spin-orbit coupling and curved

K. Bardakci; M. B. Halpern

1971-01-01

200

Rock Properties Model  

SciTech Connect

The purpose of this model report is to document the Rock Properties Model version 3.1 with regard to input data, model methods, assumptions, uncertainties and limitations of model results, and qualification status of the model. The report also documents the differences between the current and previous versions and validation of the model. The rock properties model provides mean matrix and lithophysae porosity, and the cross-correlated mean bulk density as direct input to the ''Saturated Zone Flow and Transport Model Abstraction'', MDL-NBS-HS-000021, REV 02 (BSC 2004 [DIRS 170042]). The constraints, caveats, and limitations associated with this model are discussed in Section 6.6 and 8.2. Model validation accomplished by corroboration with data not cited as direct input is discussed in Section 7. The revision of this model report was performed as part of activities being conducted under the ''Technical Work Plan for: The Integrated Site Model, Revision 05'' (BSC 2004 [DIRS 169635]). The purpose of this revision is to bring the report up to current procedural requirements and address the Regulatory Integration Team evaluation comments. The work plan describes the scope, objectives, tasks, methodology, and procedures for this process.

C. Lum

2004-09-16

201

QUALITATIVE ECOLOGICAL MODELING  

Technology Transfer Automated Retrieval System (TEKTRAN)

Students construct qualitative models of an ecosystem and use the models to evaluate the direct and indirect effects that may result from perturbations to the ecosystem. Qualitative modeling is described for use in two procedures, each with different educational goals and student backgrounds in min...

202

Migdal's model and holography  

E-print Network

Migdal's model on the spectrum of vector mesons is reassessed. We discuss how its departure from a Pade approximant is closely linked to the issue of quark-hadron duality breakdown. We also show that Migdal's model is not truly a model of large-Nc QCD.

O. Cata

2007-01-23

203

MODAL AEROSOL DYNAMICS MODEL  

EPA Science Inventory

The Modal Aerosol Dynamics (MAD) model is a computationally efficient model for solving the General Dynamics Equation of Aerosols (GDE) (Friedlander, 1977). The simplifying assumption in the model is that aerosol size distributions can be approximated by overlapping modes, each r...

204

Modeling Climate Dynamically  

ERIC Educational Resources Information Center

A dynamical systems approach to energy balance models of climate is presented, focusing on low order, or conceptual, models. Included are global average and latitude-dependent, surface temperature models. The development and analysis of the differential equations and corresponding bifurcation diagrams provides a host of appropriate material for…

Walsh, Jim; McGehee, Richard

2013-01-01

205

On solvable boson models  

SciTech Connect

The problem of equilibrium states and/or ground states of exactly solvable homogeneous boson models is stated and explicitly proved as a special case of the general variational problem of statistical mechanics in terms of quasifree states. We apply the result to a model of super-radiant Bose-Einstein condensation and to the pairing boson model.

Pule, Joe V. [School of Mathematical Sciences, University College Dublin, Belfield, Dublin 4 (Ireland); Verbeure, Andre F. [Instituut voor Theoretische Fysica, K.U. Leuven, B-3000 Leuven (Belgium); Zagrebnov, Valentin A. [Universite de la Mediterranee Centre de Physique Theorique-UMR 6207, Luminy-Case 907, 13288 Marseille, Cedex 09 (France)

2008-04-15

206

MPP Fortran Programming Model  

Microsoft Academic Search

This report describes the MPP Fortran programming model which will be supported on the first phaseMPP systems. Based on existing and proposed standards, it is a work sharing model which combinesfeatures from existing models in a way that may be both efficiently implemented and useful.

Douglas M. Pase; Tom MacDonald; Andrew Meltzer

1992-01-01

207

URBAN AIRSHED MODEL (UAM)  

EPA Science Inventory

The Urban Airshed Model (UAM) is an urban scale, three-dimensional, grid type, numerical simulation model. The model incorporates a condensed photochemical kinetics mechanism for urban atmospheres. The UAM is designed for computing ozone (O3) concentrations under short-term, epis...

208

A Model Performance  

ERIC Educational Resources Information Center

Building information modeling (BIM) uses three-dimensional modeling concepts, information technology and interoperable software to design, construct and operate a facility. However, BIM can be more than a tool for virtual modeling--it can provide schools with a 3-D walkthrough of a project while it still is on the electronic drawing board. BIM can…

Thornton, Bradley D.; Smalley, Robert A.

2008-01-01

209

Submodels of Kripke models  

Microsoft Academic Search

.   A Kripke model ? is a submodel of another Kripke model ? if ? is obtained by restricting the set of nodes of ?. In this paper we show that the class of\\u000a formulas of Intuitionistic Predicate Logic that is preserved under taking submodels of Kripke models is precisely the class\\u000a of semipositive formulas. This result is an analogue

Albert Visser

2001-01-01

210

Modelling cement grinding circuits  

Microsoft Academic Search

Modelling and simulation studies were carried out at 26 cement clinker grinding circuits including tube mills, air separators and high pressure grinding rolls in 8 plants. The results reported earlier have shown that tube mills can be modelled as several mills in series, and the internal partition in tube mills can be modelled as a screen which must retain coarse

H. Benzer; L. Ergun; A. J. Lynch; M. Oner; A. Gunlu; I. B. Celik; N. Aydogan

2001-01-01

211

IMAGE Satellite Scale Model  

NSDL National Science Digital Library

This is an activity about scale model building. Learners will use mathematics to determine the scale model size, construct a pattern, and build a paper scale model of the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite, the first satellite mission to image the Earth's magnetosphere. This is the second activity in the Solar Storms and You: Exploring Satellite Design educator guide.

212

Modeling and Parameterizing Mixed  

E-print Network

Modeling and Parameterizing Mixed Layer Eddies Baylor Fox-Kemper (MIT) with Raffaele Ferrari (MIT: Baroclinic Instabilities of the Ocean Interior and Mixed Layer Part II: Modeling and Parameterizing Mixed Layer Eddies Part III: Implementing the Parameterization in the Hallberg Isopycnal Model #12;Ocean Mixed

Fox-Kemper, Baylor

213

Succession Model Landscape Stochasticity  

E-print Network

100 1000 10000 patch sizes birth rate both Disturbance Model Landscape Stochasticity Low Control High" accomplished by incrementing the patch birth rate (Control: s = a = 10) A simple model of species viabilitySuccession Model Landscape Stochasticity Low Control High Very High ThresholdMultiplier 0.1 1 10

214

The Java memory model  

Microsoft Academic Search

This paper describes the new Java memory model, which has been revised as part of Java 5.0. The model specifies the legal behaviors for a multithreaded program; it defines the semantics of multithreaded Java programs and partially determines legal implementations of Java virtual machines and compilers.The new Java model provides a simple interface for correctly synchronized programs -- it guarantees

Jeremy Manson; William Pugh; Sarita V. Adve

2005-01-01

215

Mathematical models of hysteresis  

Microsoft Academic Search

A new approach to Preisach's hysteresis model, which emphasizes its phenomenological nature and mathematical generality, is briefly described. Then the theorem which gives the necessary and sufficient conditions for the representation of actual hysteresis nonlinearities by Preisach's model is proven. The significance of this theorem is that it establishes the limits of applicability of this model.

I. Mayergoyz

1986-01-01

216

Models for Products  

ERIC Educational Resources Information Center

This paper explores how models can support productive thinking. For us a model is a "thing", a tool to help make sense of something. We restrict attention to specific models for whole-number multiplication, hence the wording of the title. They support evolving thinking in large measure through the ways their users redesign them. They assume new…

Speiser, Bob; Walter, Chuck

2011-01-01

217

Modeling annotated data  

Microsoft Academic Search

We consider the problem of modeling annotated data---data with multiple types where the instance of one type (such as a caption) serves as a description of the other type (such as an image). We describe three hierarchical probabilistic mixture models which aim to describe such data, culminating in correspondence latent Dirichlet allocation, a latent variable model that is effective at

David M. Blei; Michael I. Jordan

2003-01-01

218

PESTICIDE ROOT ZONE MODEL  

EPA Science Inventory

PRZM3 is a modeling system that links two subordinate models - PRZM and VADOFT to predict pesticide transport and transformation down through the crop root and unsaturated zone. PRZM3 includes modeling capabilities for such phenomena as soil temperature simulation, vo...

219

Phyloclimatic Modelling Workshop  

E-print Network

– from ice cores Palaeohistory • Fossil history – Mostly pollen • Geological record – Continental drift – Climate • Computer models – Climate Alastair Culham Gathering the evidence • Fossil history is generally poor and patchy even in the best recorded... climate models? • Modelling here relies on: – Knowing continental positions – Knowing altitudes – Knowing sea levels – Knowing atmospheric gas concentrations • This can be validated against fossil evidence – Pollen/macrofossils – ‘Fossil’ atmospheres...

Yesson, Christopher

2012-11-13

220

Chaos Models in Economics  

E-print Network

The paper discusses the main ideas of the chaos theory and presents mainly the importance of the nonlinearities in the mathematical models. Chaos and order are apparently two opposite terms. The fact that in chaos can be found a certain precise symmetry (Feigenbaum numbers) is even more surprising. As an illustration of the ubiquity of chaos, three models among many other existing models that have chaotic features are presented here: the nonlinear feedback profit model, one model for the simulation of the exchange rate and one application of the chaos theory in the capital markets.

Sorin Vlad; Paul Pascu; Nicolae Morariu

2010-01-20

221

Weather Station Model  

NSDL National Science Digital Library

This lesson instructs students on how to read station models, the symbols used on weather maps to show data (temperature, wind speed and direction, barometeric pressure, etc.) for a given reporting station. It includes a diagram of a station model, an explanation of the data conveyed by the numbers and symbols, and a table of definitions for the graphic symbols used with models. There is also a set of interactive station models students can use for practice at interpretation, and an interactive exercise in which students use real-time weather data to interpret models.

222

CRAC2 model description  

SciTech Connect

The CRAC2 computer code is a revised version of CRAC (Calculation of Reactor Accident Consequences) which was developed for the Reactor Safety Study. This document provides an overview of the CRAC2 code and a description of each of the models used. Significant improvements incorporated into CRAC2 include an improved weather sequence sampling technique, a new evacuation model, and new output capabilities. In addition, refinements have been made to the atmospheric transport and deposition model. Details of the modeling differences between CRAC2 and CRAC are emphasized in the model descriptions.

Ritchie, L.T.; Alpert, D.J.; Burke, R.P.; Johnson, J.D.; Ostmeyer, R.M.; Aldrich, D.C.; Blond, R.M.

1984-03-01

223

Pediatric Computational Models  

NASA Astrophysics Data System (ADS)

A computational model is a computer program that attempts to simulate a behavior of a complex system by solving mathematical equations associated with principles and laws of physics. Computational models can be used to predict the body's response to injury-producing conditions that cannot be simulated experimentally or measured in surrogate/animal experiments. Computational modeling also provides means by which valid experimental animal and cadaveric data can be extrapolated to a living person. Widely used computational models for injury biomechanics include multibody dynamics and finite element (FE) models. Both multibody and FE methods have been used extensively to study adult impact biomechanics in the past couple of decades.

Soni, Bharat K.; Kim, Jong-Eun; Ito, Yasushi; Wagner, Christina D.; Yang, King-Hay

224

A Generalized Higgs Model  

E-print Network

The Higgs model is generalized so that in addition to the radial Higgs field there are fields which correspond to the themasy and entropy. The model is further generalized to include state and sign parameters. A reduction to the standard Higgs model is given and how to break symmetry using a non-zero VEV (vacuum expectation value) is shown. A 'fluid rotation' can be performed on the standard Higgs model to give a model dependant on the entropy and themasy and with a constant mass.

Mark D. Roberts

1999-04-11

225

Reconstruction of Inflation Models  

E-print Network

In this paper, we reconstruct viable inflationary models by starting from spectral index and tensor-to-scalar ratio from Planck observations. We analyze three different kinds of models: scalar field theories, fluid cosmology and f(R)-modified gravity. We recover the well known R^2-inflation in Jodan frame and Einstein frame representation, the massive scalar inflaton models and two models of inhomogeneous fluid. A model of R^2-correction to Einstein's gravity plus a "cosmological constant" with an exact solution for early time acceleration is reconstructed.

Myrzakulov, Ratbay; Zerbini, Sergio

2015-01-01

226

Mechanics of materials model  

NASA Technical Reports Server (NTRS)

The Mechanics of Materials Model (MOMM) is a three-dimensional inelastic structural analysis code for use as an early design stage tool for hot section components. MOMM is a stiffness method finite element code that uses a network of beams to characterize component behavior. The MOMM contains three material models to account for inelastic material behavior. These include the simplified material model, which assumes a bilinear stress-strain response; the state-of-the-art model, which utilizes the classical elastic-plastic-creep strain decomposition; and Walker's viscoplastic model, which accounts for the interaction between creep and plasticity that occurs under cyclic loading conditions.

Meister, Jeffrey P.

1987-01-01

227

A model of strength  

USGS Publications Warehouse

In her AAAS News & Notes piece "Can the Southwest manage its thirst?" (26 July, p. 362), K. Wren quotes Ajay Kalra, who advocates a particular method for predicting Colorado River streamflow "because it eschews complex physical climate models for a statistical data-driven modeling approach." A preference for data-driven models may be appropriate in this individual situation, but it is not so generally, Data-driven models often come with a warning against extrapolating beyond the range of the data used to develop the models. When the future is like the past, data-driven models can work well for prediction, but it is easy to over-model local or transient phenomena, often leading to predictive inaccuracy (1). Mechanistic models are built on established knowledge of the process that connects the response variables with the predictors, using information obtained outside of an extant data set. One may shy away from a mechanistic approach when the underlying process is judged to be too complicated, but good predictive models can be constructed with statistical components that account for ingredients missing in the mechanistic analysis. Models with sound mechanistic components are more generally applicable and robust than data-driven models.

Johnson, Douglas H.; Cook, R.D.

2013-01-01

228

Animal models of atherosclerosis  

PubMed Central

In this mini-review several commonly used animal models of atherosclerosis have been discussed. Among them, emphasis has been made on mice, rabbits, pigs and non-human primates. Although these animal models have played a significant role in our understanding of induction of atherosclerotic lesions, we still lack a reliable animal model for regression of the disease. Researchers have reported several genetically modified and transgenic animal models that replicate human atherosclerosis, however each of current animal models have some limitations. Among these animal models, the apolipoprotein (apo) E-knockout (KO) mice have been used extensively because they develop spontaneous atherosclerosis. Furthermore, atherosclerotic lesions developed in this model depending on experimental design may resemble humans’ stable and unstable atherosclerotic lesions. This mouse model of hypercholesterolemia and atherosclerosis has been also used to investigate the impact of oxidative stress and inflammation on atherogenesis. Low density lipoprotein (LDL)-r-KO mice are a model of human familial hypercholesterolemia. However, unlike apo E-KO mice, the LDL-r-KO mice do not develop spontaneous atherosclerosis. Both apo E-KO and LDL-r-KO mice have been employed to generate other relevant mouse models of cardiovascular disease through breeding strategies. In addition to mice, rabbits have been used extensively particularly to understand the mechanisms of cholesterol-induced atherosclerosis. The present review paper details the characteristics of animal models that are used in atherosclerosis research. PMID:24868511

Kapourchali, Fatemeh Ramezani; Surendiran, Gangadaran; Chen, Li; Uitz, Elisabeth; Bahadori, Babak; Moghadasian, Mohammed H

2014-01-01

229

Calibrated Properties Model  

SciTech Connect

The purpose of this model report is to document the calibrated properties model that provides calibrated property sets for unsaturated zone (UZ) flow and transport process models (UZ models). The calibration of the property sets is performed through inverse modeling. This work followed, and was planned in, ''Technical Work Plan (TWP) for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Sections 1.2.6 and 2.1.1.6). Direct inputs to this model report were derived from the following upstream analysis and model reports: ''Analysis of Hydrologic Properties Data'' (BSC 2004 [DIRS 170038]); ''Development of Numerical Grids for UZ Flow and Transport Modeling'' (BSC 2004 [DIRS 169855]); ''Simulation of Net Infiltration for Present-Day and Potential Future Climates'' (BSC 2004 [DIRS 170007]); ''Geologic Framework Model'' (GFM2000) (BSC 2004 [DIRS 170029]). Additionally, this model report incorporates errata of the previous version and closure of the Key Technical Issue agreement TSPAI 3.26 (Section 6.2.2 and Appendix B), and it is revised for improved transparency.

T. Ghezzehej

2004-10-04

230

Parallel Mandelbrot Set Model  

NSDL National Science Digital Library

The Parallel Mandelbrot Set Model is a parallelization of the sequential MandelbrotSet model, which does all the computations on a single processor core. This parallelization is able to use a computer with more than one cores (or processors) to carry out the same computation, thus speeding up the process. The parallelization is done using the model elements in the Parallel Java group. These model elements allow easy use of the Parallel Java library created by Alan Kaminsky. In particular, the parallelization used for this model is based on code in Chapters 11 and 12 of Kaminsky's book Building Parallel Java. The Parallel Mandelbrot Set Model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double click the ejs_chaos_ParallelMandelbrotSet.jar file to run the program if Java is installed.

Franciscouembre

2011-11-24

231

Physical modelling in biomechanics.  

PubMed Central

Physical models, like mathematical models, are useful tools in biomechanical research. Physical models enable investigators to explore parameter space in a way that is not possible using a comparative approach with living organisms: parameters can be varied one at a time to measure the performance consequences of each, while values and combinations not found in nature can be tested. Experiments using physical models in the laboratory or field can circumvent problems posed by uncooperative or endangered organisms. Physical models also permit some aspects of the biomechanical performance of extinct organisms to be measured. Use of properly scaled physical models allows detailed physical measurements to be made for organisms that are too small or fast to be easily studied directly. The process of physical modelling and the advantages and limitations of this approach are illustrated using examples from our research on hydrodynamic forces on sessile organisms, mechanics of hydraulic skeletons, food capture by zooplankton and odour interception by olfactory antennules. PMID:14561350

Koehl, M A R

2003-01-01

232

Oscillator Chain Model  

NSDL National Science Digital Library

The EJS Oscillator Chain model shows a one-dimensional linear array of coupled harmonic oscillators with fixed ends. This model can be used to study the propagation of waves in a continuous medium and the vibrational modes of a crystalline lattice. The Ejs model shown here contains 31 coupled oscillators equally spaced within the interval [0, 2 pi] with fixed ends. Ejs Oscillator Chain model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_mech_osc_OscillatorChain.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for classical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-11-06

233

Multiscale modeling of recrystallization  

SciTech Connect

The authors propose a multi length scale approach to modeling recrystallization which links a dislocation model, a cell growth model and a macroscopic model. Although this methodology and linking framework will be applied to recrystallization, it is also applicable to other types of phase transformations in bulk and layered materials. Critical processes such as the dislocation structure evolution, nucleation, the evolution of crystal orientations into a preferred texture, and grain size evolution all operate at different length scales. In this paper the authors focus on incorporating experimental measurements of dislocation substructures, misorientation measurements of dislocation boundaries, and dislocation simulations into a mesoscopic model of cell growth. In particular, they show how feeding information from the dislocation model into the cell growth model can create realistic initial microstructures.

Miodownik, M.A.; Holm, E.A.; Godfrey, A.W.; Hughes, D.A.; Lesar, R.

1999-07-01

234

Multiscale Modeling of Recrystallization  

SciTech Connect

We propose a multi length scale approach to modeling recrystallization which links a dislocation model, a cell growth model and a macroscopic model. Although this methodology and linking framework will be applied to recrystallization, it is also applicable to other types of phase transformations in bulk and layered materials. Critical processes such as the dislocation structure evolution, nucleation, the evolution of crystal orientations into a preferred texture, and grain size evolution all operate at different length scales. In this paper we focus on incorporating experimental measurements of dislocation substructures, rnisorientation measurements of dislocation boundaries, and dislocation simulations into a mesoscopic model of cell growth. In particular, we show how feeding information from the dislocation model into the cell growth model can create realistic initial microstructure.

Godfrey, A.W.; Holm, E.A.; Hughes, D.A.; Lesar, R.; Miodownik, M.A.

1998-12-07

235

Foam process models.  

SciTech Connect

In this report, we summarize our work on developing a production level foam processing computational model suitable for predicting the self-expansion of foam in complex geometries. The model is based on a finite element representation of the equations of motion, with the movement of the free surface represented using the level set method, and has been implemented in SIERRA/ARIA. An empirically based time- and temperature-dependent density model is used to encapsulate the complex physics of foam nucleation and growth in a numerically tractable model. The change in density with time is at the heart of the foam self-expansion as it creates the motion of the foam. This continuum-level model uses an homogenized description of foam, which does not include the gas explicitly. Results from the model are compared to temperature-instrumented flow visualization experiments giving the location of the foam front as a function of time for our EFAR model system.

Moffat, Harry K.; Noble, David R.; Baer, Thomas A. (Procter & Gamble Co., West Chester, OH); Adolf, Douglas Brian; Rao, Rekha Ranjana; Mondy, Lisa Ann

2008-09-01

236

Experiments and modeling  

NASA Technical Reports Server (NTRS)

The usual approach in establishing the correctness and accuracy of turbulence models is to numerically solve the modeled differential equations and then compare the results with the experiment. However, in the case of a discrepancy, this procedure does not pinpoint where in the model the drawback lies. It is also possible that the model overcompensates one physical phenomenon and undercompensates the other so that the net result is a good agreement between the two. Therefore, a more desirable approach is to directly compare the individual terms in the equations with their models. To achieve this objective, primary physical experiments were used to carry out the second moment budgets. These can then be used to analyze and assess various models and closure assumptions and seek improvements/modifications where models prove deficient.

Shabbir, Aamir

1991-01-01

237

Video Modeling with Tracker  

NSDL National Science Digital Library

The Tracker video analysis and modeling program enables students to create simple particle model simulations based on Newton's laws and to compare their behavior directly with that of real-world objects captured on video. Tracker's "model builder" provides a gentle introduction to dynamic modeling by making it easy to define and modify force expressions, parameter values and initial conditions while hiding the numerical algorithm details. Because the model simulations synchronize with and draw themselves right on the video, students can test their models experimentally by direct visual inspection, a process that is both intuitive and discerning. This leads them to move from a paradigm of "problem solving" to one of "model building and testing" that reflects more closely the activities of professional physicists. Tracker is part of the Open Source Physics project. Tracker is available at or from the comPADRE Open Source Physics collection at . Partial funding was provided by NSF grant DUE-0442581.

Brown, Douglas

2010-08-11

238

Electric Generator Model  

NSDL National Science Digital Library

The EJS Electric Generator Model shows a simple electric generator made from a conducting loop rotating in a uniform magnetic field and connected to an ammeter. The model shows a plot of the magnetic flux and induced current. If Ejs is installed, right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item allows for editing of the model. The Electric Generator model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_em_Generator.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Cox, Anne; Christian, Wolfgang

2009-09-22

239

Contrasting Disciplinary Models in Education.  

ERIC Educational Resources Information Center

Discusses advantages and disadvantages of eight discipline approaches: the Neo-Skinnerian reinforcement model, Redl and Wattenberg's group dynamics model, Kounin's lesson-management model, Ginott's communication model, Dreikurs' student choice model, Canter's Assertive Discipline model, Jones's classroom-management model, and Glasser's…

Morris, Robert C.

1996-01-01

240

Generalized Multilevel Structural Equation Modeling  

ERIC Educational Resources Information Center

A unifying framework for generalized multilevel structural equation modeling is introduced. The models in the framework, called generalized linear latent and mixed models (GLLAMM), combine features of generalized linear mixed models (GLMM) and structural equation models (SEM) and consist of a response model and a structural model for the latent…

Rabe-Hesketh, Sophia; Skrondal, Anders; Pickles, Andrew

2004-01-01

241

Codon Evolution Mechanisms and Models  

E-print Network

;CHAPTER 2 Parametric models of codon evolution Maria Anisimova 2.1 Basic Markov models of codon described using Markov models. This chapter focuses on parametric models--models that describe the evolution-diagonal entries minus one--to enable scaling). In contrast to DNA models, the first amino acid substitution models

Anisimova, Maria

242

A distributed model of IPMC  

Microsoft Academic Search

This paper presents a distributed model of an IPMC (Ionomeric Polymer-Metal Composite). Unlike other electromechanical models of an IPMC, the distributed nature of our model permits modelling the non-uniform bending of the material. Instead of modeling solely the tip deflection of the material, we model the changing curvature. Our model of the IPMC describes the actuator or sensor as a

A. Punning; U. Johanson; M. Anton; M. Kruusmaa; A. Aabloo

2008-01-01

243

Constitutive models in LAME.  

SciTech Connect

The Library of Advanced Materials for Engineering (LAME) provides a common repository for constitutive models that can be used in computational solid mechanics codes. A number of models including both hypoelastic (rate) and hyperelastic (total strain) constitutive forms have been implemented in LAME. The structure and testing of LAME is described in Scherzinger and Hammerand ([3] and [4]). The purpose of the present report is to describe the material models which have already been implemented into LAME. The descriptions are designed to give useful information to both analysts and code developers. Thus far, 33 non-ITAR/non-CRADA protected material models have been incorporated. These include everything from the simple isotropic linear elastic models to a number of elastic-plastic models for metals to models for honeycomb, foams, potting epoxies and rubber. A complete description of each model is outside the scope of the current report. Rather, the aim here is to delineate the properties, state variables, functions, and methods for each model. However, a brief description of some of the constitutive details is provided for a number of the material models. Where appropriate, the SAND reports available for each model have been cited. Many models have state variable aliases for some or all of their state variables. These alias names can be used for outputting desired quantities. The state variable aliases available for results output have been listed in this report. However, not all models use these aliases. For those models, no state variable names are listed. Nevertheless, the number of state variables employed by each model is always given. Currently, there are four possible functions for a material model. This report lists which of these four methods are employed in each material model. As far as analysts are concerned, this information is included only for the awareness purposes. The analyst can take confidence in the fact that model has been properly implemented and the methods necessary for achieving accurate and efficient solutions have been incorporated. The most important method is the getStress function where the actual material model evaluation takes place. Obviously, all material models incorporate this function. The initialize function is included in most material models. The initialize function is called once at the beginning of an analysis and its primary purpose is to initialize the material state variables associated with the model. Many times, there is some information which can be set once per load step. For instance, we may have temperature dependent material properties in an analysis where temperature is prescribed. Instead of setting those parameters at each iteration in a time step, it is much more efficient to set them once per time step at the beginning of the step. These types of load step initializations are performed in the loadStepInit method. The final function used by many models is the pcElasticModuli method which changes the moduli that are to be used by the elastic preconditioner in Adagio. The moduli for the elastic preconditioner are set during the initialization of Adagio. Sometimes, better convergence can be achieved by changing these moduli for the elastic preconditioner. For instance, it typically helps to modify the preconditioner when the material model has temperature dependent moduli. For many material models, it is not necessary to change the values of the moduli that are set initially in the code. Hence, those models do not have pcElasticModuli functions. All four of these methods receive information from the matParams structure as described by Scherzinger and Hammerand.

Hammerand, Daniel Carl; Scherzinger, William Mark

2007-09-01

244

Modeling and Prediction Overview  

SciTech Connect

Effective preparation for and response to the release of toxic materials into the atmosphere hinges on accurate predictions of the dispersion pathway, concentration, and ultimate fate of the chemical or biological agent. Of particular interest is the threat to civilian populations within major urban areas, which are likely targets for potential attacks. The goals of the CBNP Modeling and Prediction area are: (1) Development of a suite of validated, multi-scale, atmospheric transport and fate modeling capabilities for chemical and biological agent releases within the complex urban environment; (2) Integration of these models and related user tools into operational emergency response systems. Existing transport and fate models are being adapted to treat the complex atmospheric flows within and around structures (e.g., buildings, subway systems, urban areas) and over terrain. Relevant source terms and the chemical and physical behavior of gas- and particle-phase species (e.g., losses due to deposition, bio-agent viability, degradation) are also being developed and incorporated into the models. Model validation is performed using both laboratory and field data. CBNP is producing and testing a suite of models with differing levels of complexity and fidelity to address the full range of user needs and applications. Lumped-parameter transport models are being developed for subway systems and building interiors, supplemented by the use of computational fluid dynamics (CFD) models to describe the circulation within large, open spaces such as auditoriums. Both sophisticated CFD transport models and simpler fast-response models are under development to treat the complex flow around individual structures and arrays of buildings. Urban parameterizations are being incorporated into regional-scale weather forecast, meteorological data assimilation, and dispersion models for problems involving larger-scale urban and suburban areas. Source term and dose response models are being developed for use in the transport models. ''Rules of thumb'' provide guidance to emergency responders in situations when immediate response is necessary and model simulations are not available. These modeling capabilities and tools are being integrated into operational systems for planning and training, real time emergency response, and post-event consequence analysis. CBNP interior modeling tools are directed in large part toward implementation into the PROTECT system for CB defense of interior infrastructure facilities. CBNP's exterior modeling tools for treating CB releases within the urban environment are integrated into the existing DOE National Atmospheric Release Advisory Center (NARAC), which provides real-time atmospheric hazard assessments. Internet and Web based software tools provide authorized users with secure remote access to the operational NARAC system. NARAC plume dispersion and health-risk predictions, as well as recommended actions, aid emergency managers and first responders in coordinating multi-agency responses.

Ermak, D L

2002-10-18

245

Preliminary DIAL model  

NASA Astrophysics Data System (ADS)

A unique end-to-end LIDAR sensor model has been developed supporting the concept development stage of the CALIOPE UV DIAL and UV laser-induced-fluorescence (LIF) efforts. The model focuses on preserving the temporal and spectral nature of signals as they pass through the atmosphere, are collected by the optics, detected by the sensor, and processed by the sensor electronics and algorithms. This is done by developing accurate component sub-models with realistic inputs and outputs, as well as internal noise sources and operating parameters. These sub-models are then configured using data-flow diagrams to operate together to reflect the performance of the entire DIAL system. This modeling philosophy allows the developer to have a realistic indication of the nature of signals throughout the system and to design components and processing in a realistic environment. Current component models include atmospheric absorption and scattering losses, plume absorption and scattering losses, background, telescope and optical filter models, PMT (photomultiplier tube) with realistic noise sources, amplifier operation and noise, A/D converter operation, noise and distortion, pulse averaging, and DIAL computation. Preliminary results of the model will be presented indicating the expected model operation depicting the October field test at the NTS spill test facility. Indications will be given concerning near-term upgrades to the model.

Gentry, S.; Taylor, J.; Stephenson, D.

246

Geochemical modeling: a review  

SciTech Connect

Two general families of geochemical models presently exist. The ion speciation-solubility group of geochemical models contain submodels to first calculate a distribution of aqueous species and to secondly test the hypothesis that the water is near equilibrium with particular solid phases. These models may or may not calculate the adsorption of dissolved constituents and simulate the dissolution and precipitation (mass transfer) of solid phases. Another family of geochemical models, the reaction path models, simulates the stepwise precipitation of solid phases as a result of reacting specified amounts of water and rock. Reaction path models first perform an aqueous speciation of the dissolved constituents of the water, test solubility hypotheses, then perform the reaction path modeling. Certain improvements in the present versions of these models would enhance their value and usefulness to applications in nuclear-waste isolation, etc. Mass-transfer calculations of limited extent are certainly within the capabilities of state-of-the-art models. However, the reaction path models require an expansion of their thermodynamic data bases and systematic validation before they are generally accepted.

Jenne, E.A.

1981-06-01

247

Turbulence modeling and experiments  

NASA Technical Reports Server (NTRS)

The best way of verifying turbulence is to do a direct comparison between the various terms and their models. The success of this approach depends upon the availability of the data for the exact correlations (both experimental and DNS). The other approach involves numerically solving the differential equations and then comparing the results with the data. The results of such a computation will depend upon the accuracy of all the modeled terms and constants. Because of this it is sometimes difficult to find the cause of a poor performance by a model. However, such a calculation is still meaningful in other ways as it shows how a complete Reynolds stress model performs. Thirteen homogeneous flows are numerically computed using the second order closure models. We concentrate only on those models which use a linear (or quasi-linear) model for the rapid term. This, therefore, includes the Launder, Reece and Rodi (LRR) model; the isotropization of production (IP) model; and the Speziale, Sarkar, and Gatski (SSG) model. Which of the three models performs better is examined along with what are their weaknesses, if any. The other work reported deal with the experimental balances of the second moment equations for a buoyant plume. Despite the tremendous amount of activity toward the second order closure modeling of turbulence, very little experimental information is available about the budgets of the second moment equations. Part of the problem stems from our inability to measure the pressure correlations. However, if everything else appearing in these equations is known from the experiment, pressure correlations can be obtained as the closing terms. This is the closest we can come to in obtaining these terms from experiment, and despite the measurement errors which might be present in such balances, the resulting information will be extremely useful for the turbulence modelers. The purpose of this part of the work was to provide such balances of the Reynolds stress and heat flux equations for the buoyant plume.

Shabbir, Aamir

1992-01-01

248

Radiation Environment Modeling for Spacecraft Design: New Model Developments  

NASA Technical Reports Server (NTRS)

A viewgraph presentation on various new space radiation environment models for spacecraft design is described. The topics include: 1) The Space Radiatio Environment; 2) Effects of Space Environments on Systems; 3) Space Radiatio Environment Model Use During Space Mission Development and Operations; 4) Space Radiation Hazards for Humans; 5) "Standard" Space Radiation Environment Models; 6) Concerns about Standard Models; 7) Inadequacies of Current Models; 8) Development of New Models; 9) New Model Developments: Proton Belt Models; 10) Coverage of New Proton Models; 11) Comparison of TPM-1, PSB97, AP-8; 12) New Model Developments: Electron Belt Models; 13) Coverage of New Electron Models; 14) Comparison of "Worst Case" POLE, CRESELE, and FLUMIC Models with the AE-8 Model; 15) New Model Developments: Galactic Cosmic Ray Model; 16) Comparison of NASA, MSU, CIT Models with ACE Instrument Data; 17) New Model Developmemts: Solar Proton Model; 18) Comparison of ESP, JPL91, KIng/Stassinopoulos, and PSYCHIC Models; 19) New Model Developments: Solar Heavy Ion Model; 20) Comparison of CREME96 to CREDO Measurements During 2000 and 2002; 21) PSYCHIC Heavy ion Model; 22) Model Standardization; 23) Working Group Meeting on New Standard Radiation Belt and Space Plasma Models; and 24) Summary.

Barth, Janet; Xapsos, Mike; Lauenstein, Jean-Marie; Ladbury, Ray

2006-01-01

249

Cloud Model Bat Algorithm  

PubMed Central

Bat algorithm (BA) is a novel stochastic global optimization algorithm. Cloud model is an effective tool in transforming between qualitative concepts and their quantitative representation. Based on the bat echolocation mechanism and excellent characteristics of cloud model on uncertainty knowledge representation, a new cloud model bat algorithm (CBA) is proposed. This paper focuses on remodeling echolocation model based on living and preying characteristics of bats, utilizing the transformation theory of cloud model to depict the qualitative concept: “bats approach their prey.” Furthermore, Lévy flight mode and population information communication mechanism of bats are introduced to balance the advantage between exploration and exploitation. The simulation results show that the cloud model bat algorithm has good performance on functions optimization. PMID:24967425

Zhou, Yongquan; Xie, Jian; Li, Liangliang; Ma, Mingzhi

2014-01-01

250

Animal models of fibromyalgia  

PubMed Central

Animal models of disease states are valuable tools for developing new treatments and investigating underlying mechanisms. They should mimic the symptoms and pathology of the disease and importantly be predictive of effective treatments. Fibromyalgia is characterized by chronic widespread pain with associated co-morbid symptoms that include fatigue, depression, anxiety and sleep dysfunction. In this review, we present different animal models that mimic the signs and symptoms of fibromyalgia. These models are induced by a wide variety of methods that include repeated muscle insults, depletion of biogenic amines, and stress. All potential models produce widespread and long-lasting hyperalgesia without overt peripheral tissue damage and thus mimic the clinical presentation of fibromyalgia. We describe the methods for induction of the model, pathophysiological mechanisms for each model, and treatment profiles. PMID:24314231

2013-01-01

251

RC Circuit Model  

NSDL National Science Digital Library

RC Circuit models the dynamical behavior of a voltage source attached in series to a resistor and capacitor. The source voltage can be chosen to be either a 10 volt sinusoidal or square wave with an adjustable frequency. Users can examine and change the model if they have Ejs installed. The RC Circuit model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_em_RcCircuit.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2009-10-05

252

Falling Loop Model  

NSDL National Science Digital Library

The EJS Falling Loop Model shows a conducting loop falling out of a uniform magnetic field. Users can change the size and orientation of the loop. If Ejs is installed, right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item allows for editing of the model. The Falling Loop model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_em_FallingLoop.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Cox, Anne

2009-09-24

253

Probabilistic Mesomechanical Fatigue Model  

NASA Technical Reports Server (NTRS)

A probabilistic mesomechanical fatigue life model is proposed to link the microstructural material heterogeneities to the statistical scatter in the macrostructural response. The macrostructure is modeled as an ensemble of microelements. Cracks nucleation within the microelements and grow from the microelements to final fracture. Variations of the microelement properties are defined using statistical parameters. A micromechanical slip band decohesion model is used to determine the crack nucleation life and size. A crack tip opening displacement model is used to determine the small crack growth life and size. Paris law is used to determine the long crack growth life. The models are combined in a Monte Carlo simulation to determine the statistical distribution of total fatigue life for the macrostructure. The modeled response is compared to trends in experimental observations from the literature.

Tryon, Robert G.

1997-01-01

254

Multiscale Cancer Modeling  

PubMed Central

Simulating cancer behavior across multiple biological scales in space and time, i.e., multiscale cancer modeling, is increasingly being recognized as a powerful tool to refine hypotheses, focus experiments, and enable more accurate predictions. A growing number of examples illustrate the value of this approach in providing quantitative insight on the initiation, progression, and treatment of cancer. In this review, we introduce the most recent and important multiscale cancer modeling works that have successfully established a mechanistic link between different biological scales. Biophysical, biochemical, and biomechanical factors are considered in these models. We also discuss innovative, cutting-edge modeling methods that are moving predictive multiscale cancer modeling toward clinical application. Furthermore, because the development of multiscale cancer models requires a new level of collaboration among scientists from a variety of fields such as biology, medicine, physics, mathematics, engineering, and computer science, an innovative Web-based infrastructure is needed to support this growing community. PMID:21529163

Macklin, Paul; Cristini, Vittorio

2013-01-01

255

Modeling an HIV Particle  

NSDL National Science Digital Library

This activity helps learners visualize the Human Immunodeficiency Virus (HIV) by constructing three-dimensional HIV particle models from paper. The model to be used is a 20-sided polyhedron (icosahedron) and represents a complete viral particle. Learners combine their finished models into one mass. This is a first step toward estimating how many HIV particles could be contained inside a white blood cell before being released into the blood stream to attack new cells.

2013-05-15

256

Global Atmospheric Aerosol Modeling  

NASA Technical Reports Server (NTRS)

Global aerosol models are used to study the distribution and properties of atmospheric aerosol particles as well as their effects on clouds, atmospheric chemistry, radiation, and climate. The present article provides an overview of the basic concepts of global atmospheric aerosol modeling and shows some examples from a global aerosol simulation. Particular emphasis is placed on the simulation of aerosol particles and their effects within global climate models.

Hendricks, Johannes; Aquila, Valentina; Righi, Mattia

2012-01-01

257

Making Mendel's Model Manageable  

NSDL National Science Digital Library

Genetics is often a fascinating but difficult subject for middle level students. This engaging activity presents an approach that helps students understand how genotypes can translate into phenotypes using Gummi Bears and Gummi Dolphins to solve problems using Mendel's model, and then revising the model as necessary. Developing a model gives students a sense of how science works and how data translate into scientific ideas.

Mesmer, Karen

2006-03-01

258

Modelling Pediatric Kinematics  

PubMed Central

In the field of pediatric biomechanics, crash dummy and numerical model development suffers from too limited human subject data to directly establish response and injury values. In order to create child crash dummies and numerical models it is necessary to combine the results from real world accident and reconstruction data, scaled adult data and data from animal testing with limited child volunteer data. This paper presents the functional and biomechanical targets for child crash dummies and numerical models.

van Ratingen, M.R.; Wismans, J.

1998-01-01

259

Model confusion in chemistry  

Microsoft Academic Search

Conclusion  This paper has been a preliminary discussion of model confusion about acids and bases, presenting evidence (some of it to\\u000a be elaborated) that the Arrhenius and the Lowry-Bronsted models are confused in some textbooks, and in many students' minds.\\u000a \\u000a A similar analysis of other concepts in chemistry (are some problems about ions a results of carrying Daltonian and Newtonian\\u000a models

Malcolm Carr

1984-01-01

260

Mass Balance Model  

NSDL National Science Digital Library

In this JAVA-based interactive modeling activity, students are introduced to the concept of mass balance, flow rates, and equilibrium using a simple water bucket model. Students can vary flow rate into the bucket, initial water level in the bucket, and residence time of water in the bucket. After running the model, the bucket's water level as a function of time is presented graphically and in tabular form.

Mackay, Robert; Science Education Resource Center, Starting P.

261

Morphological modeling of neurons  

E-print Network

Strings of Parenthe- sized Terminal Symbols . . B. Turtle Rotations are Defined in the Local Reference Frame C. The Reference Frame Can be Generalized to Piecewise Linear Trajectories D, L-systems Can Generate Geometric Models . E. Depth...]. Turtle geometric interpretation of the strings generated by the L-system grammar allows the geometric modeling of plants. Today L-systems are an accepted tool in plant modeling[12]. Neurons, scaled by 10, show a strong resemblance to trees...

Mulchandani, Kishore

1995-01-01

262

Business process Modeling Language  

Microsoft Academic Search

Abstract The Business Process Modeling Language (BPML) specification provides an abstract model for expressing business processes,and supporting entities. BPML defines a formal model for expressing abstract and executable processes,thataddress,all aspects of enterprise business processes, including activities of varying complexity, transactions and their compensation, data management, concurrency, exception handling and operational semantics. BPML also provides a grammar in the form of

A. Arkin

2002-01-01

263

Dynamical holographic QCD model  

NASA Astrophysics Data System (ADS)

We develop a dynamical holographic QCD model, which resembles the renormalization group from ultraviolet (UV) to infrared (IR). The dynamical holographic model is constructed in the graviton-dilaton-scalar framework with the dilaton background field ? and scalar field X responsible for the gluodynamics and chiral dynamics, respectively. We summarize the results on hadron spectra, QCD phase transition and transport properties including the jet quenching parameter and the shear/bulk viscosity in the framework of the dynamical holographic QCD model.

Li, Danning; Huang, Mei

2014-11-01

264

Thin Film Interference Model  

NSDL National Science Digital Library

The Thin Film Interference model investigates reflection and transmission of light through a thin film. The user can change the thickness and index of refraction of the thin film as well as the incident light wavelength. The Thin Film Interference Model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_ThinFilm.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-25

265

Roller Coaster Model  

NSDL National Science Digital Library

The EJS Roller Coaster model explores the relationship between kinetic, potential, and total energy as a cart travels along a roller coaster. Users can create their own roller coaster curve and observe the resulting motion. The Roller Coaster model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed.

Gallis, Michael R.

2008-10-27

266

Modeling Carbon Dioxide Levels  

NSDL National Science Digital Library

In this activity students will explore levels of Carbon Dioxide ( C02) in the atmosphere over time. There is concern that levels of C02 are rising; and finding a good mathematical model for CO2 levels is an important part of determining if this is attributable to human technology. Students draw a scatter plot, choose two points to create a linear model for the data, then use the model to make predictions.

2009-01-01

267

A Model Parasite  

NSDL National Science Digital Library

In this detailed activity (on pages 9-18), learners investigate the body parts of a parasitic ascaris worm by making and dissecting clay models. Each learner creates a model of either a male or female worm, then they swap models, predict the sex of their new worm, and dissect it to check their prediction. Labels are provided for marking the parts of the dissected models. The activity introduces learners to the structure and function of digestive and reproductive organs of organisms that can live in the human body and cause disease.

2014-01-28

268

Numerical dynamo models  

NSDL National Science Digital Library

This page from the Swiss Federal Institute of Technology explains current research modeling geomagnetic processes, including magnetic reversals and secular variation. Includes three supporting figures.

Jackson, Andrew; Finlay, Chris; Zurich, Eth

269

The LISA Integrated Model  

NASA Technical Reports Server (NTRS)

The Laser Interferometer Space Antenna (LISA) space mission has unique needs that argue for an aggressive modeling effort. These models ultimately need to forecast and interrelate the behavior of the science input, structure, optics, control systems, and many other factors that affect the performance of the flight hardware. In addition, many components of these integrated models will also be used separately for the evaluation and investigation of design choices, technology development and integration and test. This article presents an overview of the LISA integrated modeling effort.

Merkowitz, Stephen M.

2002-01-01

270

Carbon Temperature Model  

NSDL National Science Digital Library

With this carbon/temperature interactive model, students investigate the role of atmospheric carbon in the greenhouse effect using a relationship between atmospheric carbon dioxide and global temperature.

NASA: Challenger Center

271

Lightning return stroke models  

NASA Technical Reports Server (NTRS)

We test the two most commonly used lightning return stroke models, Bruce-Golde and transmission line, against subsequent stroke electric and magnetic field wave forms measured simultaneously at near and distant stations and show that these models are inadequate to describe the experimental data. We then propose a new return stroke model that is physically plausible and that yields good approximations to the measured two-station fields. Using the new model, we derive return stroke charge and current statistics for about 100 subsequent strokes.

Lin, Y. T.; Uman, M. A.; Standler, R. B.

1980-01-01

272

Models of Holographic superconductivity  

E-print Network

We construct general models for holographic superconductivity parametrized by three couplings which are functions of a real scalar field and show that under general assumptions they describe superconducting phase transitions. While some features are universal and model independent, important aspects of the quantum critical behavior strongly depend on the choice of couplings, such as the order of the phase transition and critical exponents of second-order phase transitions. In particular, we study a one-parameter model where the phase transition changes from second to first order above some critical value of the parameter and a model with tunable critical exponents.

Francesco Aprile; Jorge G. Russo

2009-12-02

273

NARSTO NE MODEL  

Atmospheric Science Data Center

... Station Instrument:  Chemiluminescence UV Ozone Detector Location:  Northeastern United States ... Files:  NE Model Readme Hourly Surface Air Quality Ozone & Nitrogen Measurement Sites Related Data:  ...

2014-04-25

274

Models of Reality.  

SciTech Connect

Conscious awareness of our environment is based on a feedback loop comprised of sensory input transmitted to the central nervous system leading to construction of our ''model of the world,'' (Lewis et al, 1982). We then assimilate the neurological model at the unconscious level into information we can later consciously consider useful in identifying belief systems and behaviors for designing diverse systems. Thus, we can avoid potential problems based on our open-to-error perceived reality of the world. By understanding how our model of reality is organized, we allow ourselves to transcend content and develop insight into how effective choices and belief systems are generated through sensory derived processes. These are the processes which provide the designer the ability to meta model (build a model of a model) the user; consequently, matching the mental model of the user with that of the designer's and, coincidentally, forming rapport between the two participants. The information shared between the participants is neither assumed nor generalized, it is closer to equivocal; thus minimizing error through a sharing of each other's model of reality. How to identify individual mental mechanisms or processes, how to organize the individual strategies of these mechanisms into useful patterns, and to formulate these into models for success and knowledge based outcomes is the subject of the discussion that follows.

Brown-VanHoozer, S. A.

1999-06-02

275

Oscillator Chain JS Model  

NSDL National Science Digital Library

The EJS Oscillator Chain model shows a one-dimensional linear array of coupled harmonic oscillators with fixed ends. This model can be used to study the propagation of waves in a continuous medium and the vibrational modes of a crystalline lattice. The Ejs model shown here contains 31 coupled oscillators equally spaced within the interval [0, 2 pi] with fixed ends. The Oscillator Chain JS Model was developed using the Easy Java Simulations (Ejs) version 5. It is distributed as a ready-to-run html page and requires only a browser with JavaScript support.

Christian, Wolfgang

2013-08-25

276

Models and phenomenology  

E-print Network

It is evident that models of the knee should match the observational phenomenology. In this talk I discuss a few aspects of phenomenology, which are important not only for the understanding of the knee origin, but also for the general problem of the origin of cosmic rays. Among them are the shape of the energy spectrum, its irregularity, the sharpness of the knee and its fine structure. The classification of models is given and some examples of the most recent models are discussed. The most probable conclusion deduced from this examination is that the knee has an astrophysical origin and the so called 'source' models of the knee are most likely among them.

A. D. Erlykin

2004-11-09

277

Interference Model: Ripple Tank  

NSDL National Science Digital Library

The Interference Model: Ripple Tank investigates constructive and destructive interference between two point sources. The user can change the point source frequency, location and separation and phase difference between the point sources. The model also shows the difference in distance from the point sources to a movable observation point. The Interference Model: Ripple Tank was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_Ripple_Tank_Interference.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-25

278

Animal models of schizophrenia.  

PubMed

Schizophrenia may well represent one of the most heterogenous mental disorders in human history. This heterogeneity encompasses (1) etiology; where numerous putative genetic and environmental factors may contribute to disease manifestation, (2) symptomatology; with symptoms characterized by group; positive--behaviors not normally present in healthy subjects (e.g. hallucinations), negative--reduced expression of normal behaviors (e.g. reduced joy), and cognitive--reduced cognitive capabilities separable from negative symptoms (e.g. impaired attention), and (3) individual response variation to treatment. The complexity of this uniquely human disorder has complicated the development of suitable animal models with which to assay putative therapeutics. Moreover, the development of animal models is further limited by a lack of positive controls because currently approved therapeutics only addresses psychotic symptoms, with minor negative symptom treatment. Despite these complexities however, many animal models of schizophrenia have been developed mainly focusing on modeling individual symptoms. Validation criteria have been established to assay the utility of these models, determining the (1) face, (2) predictive, (3) construct, and (4) etiological validities, as well as (5) reproducibility of each model. Many of these models have been created following the development of major hypotheses of schizophrenia, including the dopaminergic, glutamatergic, and neurodevelopmental hypotheses. The former two models have largely consisted of manipulating these neurotransmitter systems to produce behavioral abnormalities with some relevance to symptoms or putative etiology of schizophrenia. Given the serotonergic link to hallucinations and cholinergic link to attention, other models have manipulated these systems also. Finally, there has also been a drive toward creating mouse models of schizophrenia utilizing transgenic technology. Thus, there are opportunities to combine both environmental and genetic factors to create more suitable models of schizophrenia. More sophisticated animal tasks are also being created with which to ascertain whether these models produce behavioral abnormalities consistent with patients with schizophrenia. While animal models of schizophrenia continue to be developed, we must be cognizant that (1) validating these models are limited to the degree by which Clinicians can provide relevant information on the behavior of these patients, and (2) any putative treatments that are developed are also likely to be given with concurrent antipsychotic treatment. While our knowledge of this devastating disorder increases and our animal models and tasks with which to measure their behaviors become more sophisticated, caution must still be taken when validating these models to limit complications when introducing putative therapeutics to human trials. PMID:21312408

Young, Jared W; Zhou, Xianjin; Geyer, Mark A

2010-01-01

279

Modeling Earth's Energy Balance  

NSDL National Science Digital Library

In this activity, learners use the STELLA box modeling software to determine Earth's temperature based on incoming solar radiation and outgoing terrestrial radiation. Starting with a simple black body model, the exercise gradually adds complexity by incorporating albedo, then a 1-layer atmosphere, then a 2-layer atmosphere, and finally a complex atmosphere with latent and sensible heat fluxes. With each step, students compare the modeled surface temperature to Earth's actual surface temperature, thereby providing a check on how well each increasingly complex model captures the physics of the actual system.

Menking, Kirsten; College, Vassar; Science Education Resource Center, On T.

280

Modelling approaches in biomechanics.  

PubMed Central

Conceptual, physical and mathematical models have all proved useful in biomechanics. Conceptual models, which have been used only occasionally, clarify a point without having to be constructed physically or analysed mathematically. Some physical models are designed to demonstrate a proposed mechanism, for example the folding mechanisms of insect wings. Others have been used to check the conclusions of mathematical modelling. However, others facilitate observations that would be difficult to make on real organisms, for example on the flow of air around the wings of small insects. Mathematical models have been used more often than physical ones. Some of them are predictive, designed for example to calculate the effects of anatomical changes on jumping performance, or the pattern of flow in a 3D assembly of semicircular canals. Others seek an optimum, for example the best possible technique for a high jump. A few have been used in inverse optimization studies, which search for variables that are optimized by observed patterns of behaviour. Mathematical models range from the extreme simplicity of some models of walking and running, to the complexity of models that represent numerous body segments and muscles, or elaborate bone shapes. The simpler the model, the clearer it is which of its features is essential to the calculated effect. PMID:14561333

Alexander, R McN

2003-01-01

281

Crow process modeling  

SciTech Connect

Western Research Institute (wRI) has developed a numerical model (TCROW) to describe CROW{sup TM} processing of contaminated aquifers. CROW is a patented technology for the removal of contaminant organics from water-saturated formations by injection of hot water or low- temperature steam. TCROW is based on a fully implicit, thermal, compositional model (TSRS) previously developed by wRI. TCROW`s formulation represents several enhancements and simplifications over TSRS and results in a model specifically tailored to model the CROW process.

NONE

1997-04-01

282

A BPS Skyrme model  

NASA Astrophysics Data System (ADS)

Within the set of generalized Skyrme models, we identify a submodel which has both infinitely many symmetries and a Bogomolny bound which is saturated by infinitely many exact soliton solutions. Concretely, the submodel consists of the square of the baryon current and a potential term only. Further, already on the classical level, this BPS Skyrme model reproduces some features of the liquid drop model of nuclei. Here, we review the properties of the model and we discuss the semiclassical quantization of the simplest Skyrmion (the nucleon).

Adam, C.; Sanchez-Guillen, J.; Wereszczynski, A.

2011-03-01

283

Central Force JS Model  

NSDL National Science Digital Library

The Central Force JavaScript Model computes the trajectory of a particle acted on by a central force.  The model reads uses a JavaScript mathematical expression parser to read the force and a adaptive step Runge-Kutta 5(4) algorithm to compute the trajectory.  This model is designed to test the speed of the JS parser and the accuracy of the EJS JavaScript ODE solver. The Central Force JS Model was developed using the Easy Java Simulations (EJS) version 5. It is distributed as a ready-to-run html page and requires only a browser with JavaScript support.

Christian, Wolfgang

2013-09-01

284

Motivation Model Results Summary A generative model for feedback networks  

E-print Network

Motivation Model Results Summary A generative model for feedback networks D.R. White1 N. Kejzar2 C #12;Motivation Model Results Summary Outline 1 Motivation An example 2 Model 3 Results Network properties Simulations #12;Motivation Model Results Summary Cycle formation in growing network How to model

White, Douglas R.

285

Bayesian Data-Model Fit Assessment for Structural Equation Modeling  

ERIC Educational Resources Information Center

Bayesian approaches to modeling are receiving an increasing amount of attention in the areas of model construction and estimation in factor analysis, structural equation modeling (SEM), and related latent variable models. However, model diagnostics and model criticism remain relatively understudied aspects of Bayesian SEM. This article describes…

Levy, Roy

2011-01-01

286

Large Modelling Conditional Covariance in the Linear Mixed Model  

E-print Network

Large Modelling Conditional Covariance in the Linear Mixed Model Jianxin Pan & Gilbert Mac of Mathematics, The University of Manchester #12;Modelling Conditional Covariance in the Linear Mixed Model for modelling the conditional, within subject, covariance matrix arising in linear mixed models (Laird and Ware

Sidorov, Nikita

287

GRAPHICAL MODELS FOR RELATIONS Modeling Relational Context  

E-print Network

entities. The parameters in the multinomial model are derived from factorizing multi-way contingency tables- servation that a particular user u watches a particular movie m, let C be the contingency table of observed user/movie pairs, and let ^C be the factorized and nor- malized contingency table. Then we would

Tresp, Volker

288

Modeling Imports in a Keynesian Expenditure Model  

ERIC Educational Resources Information Center

The author discusses several issues that instructors of introductory macroeconomics courses should consider when introducing imports in the Keynesian expenditure model. The analysis suggests that the specification of the import function should partially, if not completely, be the result of a simple discussion about the spending and import…

Findlay, David W.

2010-01-01

289

INSTRUCTION MANUAL MODEL AA-2010  

E-print Network

INSTRUCTION MANUAL . MODEL AA-2010 MODEL AA-2015 MODEL AA-2020 MODEL AA-2025 SINGLE CHANNEL NUCLEAR spectroscopy lies in the wide ranging versatility of the technique. From a sub-visual microsecond light flash

Bayindir, Mehmet

290

BioVapor Model Evaluation  

EPA Science Inventory

General background on modeling and specifics of modeling vapor intrusion are given. Three classical model applications are described and related to the problem of petroleum vapor intrusion. These indicate the need for model calibration and uncertainty analysis. Evaluation of Bi...

291

Performance Modeling Of Interactive Gaming  

E-print Network

Performance Modeling Of Interactive Gaming A.F. Wattimena May 2006 #12;Performance Modeling of Interactive Gaming ii #12;Performance Modeling of Interactive Gaming iii Performance Modeling of Interactive Gaming Alexander Franciscus Wattimena

Bhulai, Sandjai

292

Operator spin foam models  

NASA Astrophysics Data System (ADS)

The goal of this paper is to introduce a systematic approach to spin foams. We define operator spin foams, that is foams labelled by group representations and operators, as our main tool. A set of moves we define in the set of the operator spin foams (among other operations) allows us to split the faces and the edges of the foams. We assign to each operator spin foam a contracted operator, by using the contractions at the vertices and suitably adjusted face amplitudes. The emergence of the face amplitudes is the consequence of assuming the invariance of the contracted operator with respect to the moves. Next, we define spin foam models and consider the class of models assumed to be symmetric with respect to the moves we have introduced, and assuming their partition functions (state sums) are defined by the contracted operators. Briefly speaking, those operator spin foam models are invariant with respect to the cellular decomposition, and are sensitive only to the topology and colouring of the foam. Imposing an extra symmetry leads to a family we call natural operator spin foam models. This symmetry, combined with assumed invariance with respect to the edge splitting move, determines a complete characterization of a general natural model. It can be obtained by applying arbitrary (quantum) constraints on an arbitrary BF spin foam model. In particular, imposing suitable constraints on a spin(4) BF spin foam model is exactly the way we tend to view 4D quantum gravity, starting with the BC model and continuing with the Engle-Pereira-Rovelli-Livine (EPRL) or Freidel-Krasnov (FK) models. That makes our framework directly applicable to those models. Specifically, our operator spin foam framework can be translated into the language of spin foams and partition functions. Among our natural spin foam models there are the BF spin foam model, the BC model, and a model corresponding to the EPRL intertwiners. Our operator spin foam framework can also be used for more general spin foam models which are not symmetric with respect to one or more moves we consider.

Bahr, Benjamin; Hellmann, Frank; Kami?ski, Wojciech; Kisielowski, Marcin; Lewandowski, Jerzy

2011-05-01

293

Biosphere Process Model Report  

SciTech Connect

To evaluate the postclosure performance of a potential monitored geologic repository at Yucca Mountain, a Total System Performance Assessment (TSPA) will be conducted. Nine Process Model Reports (PMRs), including this document, are being developed to summarize the technical basis for each of the process models supporting the TSPA model. These reports cover the following areas: (1) Integrated Site Model; (2) Unsaturated Zone Flow and Transport; (3) Near Field Environment; (4) Engineered Barrier System Degradation, Flow, and Transport; (5) Waste Package Degradation; (6) Waste Form Degradation; (7) Saturated Zone Flow and Transport; (8) Biosphere; and (9) Disruptive Events. Analysis/Model Reports (AMRs) contain the more detailed technical information used to support TSPA and the PMRs. The AMRs consists of data, analyses, models, software, and supporting documentation that will be used to defend the applicability of each process model for evaluating the postclosure performance of the potential Yucca Mountain repository system. This documentation will ensure the traceability of information from its source through its ultimate use in the TSPA-Site Recommendation (SR) and in the National Environmental Policy Act (NEPA) analysis processes. The objective of the Biosphere PMR is to summarize (1) the development of the biosphere model, and (2) the Biosphere Dose Conversion Factors (BDCFs) developed for use in TSPA. The Biosphere PMR does not present or summarize estimates of potential radiation doses to human receptors. Dose calculations are performed as part of TSPA and will be presented in the TSPA documentation. The biosphere model is a component of the process to evaluate postclosure repository performance and regulatory compliance for a potential monitored geologic repository at Yucca Mountain, Nevada. The biosphere model describes those exposure pathways in the biosphere by which radionuclides released from a potential repository could reach a human receptor. Collectively, the potential human receptor and exposure pathways form the biosphere model. More detailed technical information and data about potential human receptor groups and the characteristics of exposure pathways have been developed in a series of AMRs and Calculation Reports.

J. Schmitt

2000-05-25

294

Principles of epidemiological modelling.  

PubMed

Epidemiological modelling can be a powerful tool to assist animal health policy development and disease prevention and control. Models can vary from simple deterministic mathematical models through to complex spatially-explicit stochastic simulations and decision support systems. The approach used will vary depending on the purpose of the study, how well the epidemiology of a disease is understood, the amount and quality of data available, and the background and experience of the modellers. Epidemiological models can be classified into various categories depending on their treatment of variability, chance and uncertainty (deterministic or stochastic), time (continuous or discrete intervals), space (non-spatial or spatial) and the structure of the population (homogenous or heterogeneous mixing). The increasing sophistication of computers, together with greater recognition of the importance of spatial elements in the spread and control of disease, mean that models which incorporate spatial components are becoming more important in epidemiological studies. Multidisciplinary approaches using a range of new technologies make it possible to build more sophisticated models of animal disease. New generation epidemiological models enable disease to be studied in the context of physical, economic, technological, health, media and political infrastructures. To be useful in policy development, models must be fit for purpose and appropriately verified and validated. This involves ensuring that the model is an adequate representation of the system under study and that its outputs are sufficiently accurate and precise for the intended purpose. Finally, models are just one tool for providing technical advice, and should not be considered in isolation from data from experimental and field studies. PMID:21961213

Garner, M G; Hamilton, S A

2011-08-01

295

Modeling and simulation of friction  

Microsoft Academic Search

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

David A. Haessig; Bernard Friedland

1991-01-01

296

Hierarchical Models in the Brain  

Microsoft Academic Search

This paper describes a general model that subsumes many parametric models for continuous data. The model comprises hidden layers of state-space or dynamic causal models, arranged so that the output of one provides input to another. The ensuing hierarchy furnishes a model for many types of data, of arbitrary complexity. Special cases range from the general linear model for static

Karl Friston

2008-01-01

297

Active Shape Models - 'Smart Snakes  

Microsoft Academic Search

We describe 'Active Shape Models' which iteratively adapt to refine esti- mates of the pose, scale and shape of models of image objects. The method uses flexible models derived from sets of training examples. These models, known as Point Distribution Models, represent objects as sets of labelled points. An initial estimate of the location of the model points in an

T. F. Cootes; C. J. Taylor

1992-01-01

298

Models in Biology.  

ERIC Educational Resources Information Center

Addresses the most popular models currently being chosen for biological research and the reasons behind those choices. Among the current favorites are zebra fish, fruit flies, mice, monkeys, and yeast. Concludes with a brief examination of the ethical issues involved, and why some animals may need to be replaced in research with model systems.…

Flannery, Maura C.

1997-01-01

299

Composite Load Model Evaluation  

SciTech Connect

The WECC load modeling task force has dedicated its effort in the past few years to develop a composite load model that can represent behaviors of different end-user components. The modeling structure of the composite load model is recommended by the WECC load modeling task force. GE Energy has implemented this composite load model with a new function CMPLDW in its power system simulation software package, PSLF. For the last several years, Bonneville Power Administration (BPA) has taken the lead and collaborated with GE Energy to develop the new composite load model. Pacific Northwest National Laboratory (PNNL) and BPA joint force and conducted the evaluation of the CMPLDW and test its parameter settings to make sure that: • the model initializes properly, • all the parameter settings are functioning, and • the simulation results are as expected. The PNNL effort focused on testing the CMPLDW in a 4-bus system. An exhaustive testing on each parameter setting has been performed to guarantee each setting works. This report is a summary of the PNNL testing results and conclusions.

Lu, Ning; Qiao, Hong (Amy)

2007-09-30

300

Symmetry and Model Checking  

Microsoft Academic Search

We show how to exploit symmetry in model checking for concurrent systems containing many identical or isomorphic components. We focus in particular on those composed of many isomorphic processes. In many cases we are able to obtain significant, even exponential, savings in the complexity of model checking.

E. Allen Emerson; A. Prasad Sistla

1993-01-01

301

Bitzer's Model Reconstructed.  

ERIC Educational Resources Information Center

Reconstructs Lloyd Bitzer's situational model to serve as a guide for the generation of multiperspectival critical assessments of rhetorical discourse. Uses two of President Bush's speeches on the drug crisis to illustrate how the reconstructed model can account for such modern problems as multiple audiences, perceptions, and exigencies. (PA)

Lybarger, Scott; Smith, Craig R.

1996-01-01

302

Modelling television programming choices  

Microsoft Academic Search

The paper extends Waterman's application of Salop's monopolistically competitive model of circular product space to television programming, by introducing considerations of a program's breadth of appeal and consumer intensity of demand in the analysis of programming choices. The effects of external cultural benefits associated with domestic programming are also examined. Consistent with the findings of previous researchers, the model illustrates

Franco Papandrea

1997-01-01

303

STREAM WATER QUALITY MODEL  

EPA Science Inventory

QUAL2K (or Q2K) is a river and stream water quality model that is intended to represent a modernized version of the QUAL2E (or Q2E) model (Brown and Barnwell 1987). Q2K is similar to Q2E in the following respects: One dimensional. The channel is well-mixed vertically a...

304

AGRICULTURAL SIMULATION MODEL (AGSIM)  

EPA Science Inventory

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

305

DYNAMIC ESTUARY MODEL PERFORMANCE  

EPA Science Inventory

Applications of the Dynamic Estuary Model (DEM) to both the Delaware and Potomac Estuaries by the Environmental Protection Agency during the 1970s are summarized and evaluated. Methods for calibrating, refining, and validating this model, and statistics for evaluating its perform...

306

Make a Model Fossil  

NSDL National Science Digital Library

This activity is a combination outdoor/indoor lab where students will collect natural materials from the environment and use them to create both a mold and cast model of a fossil. Students will learn how a fossil is formed and why scientists use models to help them understand how things work and develop.

307

VENTURI SCRUBBER PERFORMANCE MODEL  

EPA Science Inventory

The paper presents a new model for predicting the particle collection performance of venturi scrubbers. It assumes that particles are collected by atomized liquid only in the throat section. The particle collection mechanism is inertial impaction, and the model uses a single drop...

308

A Simple Comptonization Model  

NASA Astrophysics Data System (ADS)

We present an empirical model of Comptonization for fitting the spectra of X-ray binaries. This model, named simpl, has been developed as a package implemented in XSPEC. With only two free parameters, simpl is competitive as the simplest model of Compton scattering. Unlike the pervasive standard power-law model, simpl incorporates the basic features of Compton scattering of soft photons by energetic coronal electrons. Using a simulated spectrum, we demonstrate that simpl closely matches the behavior of physical Comptonization models that consider the effects of optical depth, coronal electron temperature, and geometry. We present fits to RXTE spectra of the black hole transient H1743-322 and a BeppoSAX spectrum of LMC X-3 using both simpl and the standard power-law model. A comparison of the results shows that simpl gives equally good fits, while eliminating the troublesome divergence of the standard power-law model at low energies. simpl is completely flexible and can be used self-consistently with any seed spectrum of photons. We show an example of how simpl-unlike the standard power law-teamed up with diskbb (the standard model of disk accretion) provides a uniform disk normalization that is unaffected by moderate Comptonization.

Steiner, James F.; Narayan, Ramesh; McClintock, Jeffrey E.; Ebisawa, Ken

2009-11-01

309

Preliminary semiempirical transport models  

SciTech Connect

A class of semiempirical transport models is proposed for testing against confinement data from tokamaks and for use in operations planning and machine design. A reference model is proposed to be compatible with published confinement data. Theoretical considerations are used to express the anomalous transport coefficients in terms of appropriate dimensionless parameters.

Singer, C.E.

1983-11-01

310

A Model for Implementation.  

ERIC Educational Resources Information Center

Describes the Constructural Multi-Modalities Model for MST (math, science, and technology) Inquiry Units. The MST Model uses an interdisciplinary and constructivist approach and allows teachers to create lesson plans that: integrate MST in tandem; adhere to local, state, and national standards; and actively engage students' differentiated learning…

O'Connor-Petruso, Sharon Anne

2003-01-01

311

String Model Building  

SciTech Connect

In this talk I review some recent progress in heterotic and F theory model building. I then consider work in progress attempting to find the F theory dual to a class of heterotic orbifold models which come quite close to the MSSM.

Raby, Stuart [Physics Department, Ohio State University, 191 W. Woodruff Ave., Columbus, OH 43210 (United States)

2010-02-10

312

MODELING PIGEONPEA PHENOLOGY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pigeonpea (Cajanus cajan (L.) Millsp.) is a widely grown legume in tropical and subtropical areas. A crop simulation model that can assist in farmer decision-making was developed. The phenological module is one of the major elements of the crop model because accurate prediction of the timing of gr...

313

Mathematical Model of Filariasis  

Microsoft Academic Search

A model of man-parasite-mosquito interaction in filariasis is formulated with a system of differential and integrodifferential equations. The model predicts that when the product of population densities of human beings and mosquitoes exceed a critical value, the system becomes unstable and the number of infectives begins to increase exponentially with time approaching an asymptotically stable equilibrium. When this product is

K. TENNAKONE

1983-01-01

314

Math, Science, and Models  

ERIC Educational Resources Information Center

For the past five summers, the authors have taught summer school to recent immigrants and refugees. Their experiences with these fourth-grade English language learners (ELL) have taught them the value of using models to build scientific and mathematical concepts. In this article, they describe the use of different forms of 2- and 3-D models to…

Weinburgh, Molly; Silva, Cecilia

2011-01-01

315

LONGPRO Stream Modeling Exercise  

NSDL National Science Digital Library

The purpose of this exercise is to integrate modeling with field data. The activity includes links to a "virtual field trip" of maps and photographs. Data from a creek is included in the field trip and students use an Excel spreadsheet model to analyze the data.

Bill Locke

316

Speechreading using Probabilistic Models  

Microsoft Academic Search

We describe a robust method for locating and tracking lips in gray-level image sequences. Our approach learns patterns of shape variability from a training set which constrains the model during image search to only deform in ways similar to the training examples. Image search is guided by a learned gray-level model which is used to describe the large appearance variability

Juergen Luettin; Neil A. Thacker

1997-01-01

317

Introduction to Population Modeling.  

ERIC Educational Resources Information Center

The focus is on the formulation and solution of mathematical models with the idea of a population employed mainly as a pedogogical tool. If the biological setting is stripped away, the material can be interpreted as topics or the qualitative behavior of differential and difference equations. The first group of models investigate the dynamics of a…

Frauenthal, James C.

318

Modelling Takeover Likelihood  

Microsoft Academic Search

This paper employs a multinomial logit model in an attempt to better understand the motives behind takeovers. The results from the multinomial logit models show that the characteristics of hostile and friendly targets differ significantly and that these differences also vary depending on the time period under investigation. The results give some support to the disciplining role of the hostile

Ronan G. Powell

1997-01-01

319

Multilevel Mixture Factor Models  

ERIC Educational Resources Information Center

Factor analysis is a statistical method for describing the associations among sets of observed variables in terms of a small number of underlying continuous latent variables. Various authors have proposed multilevel extensions of the factor model for the analysis of data sets with a hierarchical structure. These Multilevel Factor Models (MFMs)…

Varriale, Roberta; Vermunt, Jeroen K.

2012-01-01

320

Using Models Effectively  

ERIC Educational Resources Information Center

Models are crucial to science teaching and learning, yet they can create unforeseen and overlooked challenges for students and teachers. For example, consider the time-tested clay volcano that relies on a vinegar and-baking-soda mixture for its "eruption." Based on a classroom demonstration of that geologic model, elementary students may interpret…

Eichinger, John

2005-01-01

321

Reasoning and Formal Modelling  

E-print Network

Reasoning and Formal Modelling for Forensic Science Lecture 2 Prof. Dr. Benedikt L¨owe What for Forensic Science Lecture 2 Prof. Dr. Benedikt L¨owe What is logic anyway? The Wason task Syntax, Semantics, Pragmatics Assessment and grade (1). #12;Reasoning and Formal Modelling for Forensic Science Lecture 2 Prof

Löwe, Benedikt

322

Modelling behavioural contagion  

PubMed Central

The last decade has seen much work on quantitative understanding of human behaviour, with online social interaction offering the possibility of more precise measurement of behavioural phenomena than was previously possible. A parsimonious model is proposed that incorporates several observed features of behavioural contagion not seen in existing epidemic model schemes, leading to metastable behavioural dynamics. PMID:21325317

House, Thomas

2011-01-01

323

Space Ship Pilot Model  

NSDL National Science Digital Library

The Space Ship Pilot model is a model of motion under Newton's laws with and without resistive forces. The first environment puts the user in control of docking a space shuttle, and the second puts the user in control of docking a boat.

Joiner, David; The Shodor Education Foundation, Inc.

324

Modelling of COIL lasers  

Microsoft Academic Search

The modelling of chemical oxygen iodine lasers (COIL's) is discussed. A qualitative description of the system hardware elements and the major physical processes occurring in the laser is presented. Next, a steady one-dimensional model of the oxygen iodine laser system which includes the effects of area change, heat transfer, friction, mass injection and removal, changes in molecular weight and specific

D. H. Lewis Jr.; C. W. Clendening

1982-01-01

325

Model Reading Institute.  

ERIC Educational Resources Information Center

The 1978 Summer Reading Institute, which served 58 Washington, D.C., elementary school children, is described in this paper. Major characteristics of the program model are first identified, along with elements that were added to the model in the preplanning stage. Numerous aspects of the program are then described, including the make-up of the…

Dworkin, Nancy; Dworkin, Yehoash

326

Modeling Carbon Exchange  

NASA Technical Reports Server (NTRS)

Model results will be reviewed to assess different methods for bounding the terrestrial role in the global carbon cycle. It is proposed that a series of climate model runs could be scoped that would tighten the limits on the "missing sink" of terrestrial carbon and could also direct future satellite image analyses to search for its geographical location and understand its seasonal dynamics.

Sellers, Piers

2012-01-01

327

SCARP2 Model  

NSDL National Science Digital Library

This exercise is a second or familiarization exercise in spreadsheeting, but is also a mathematical model for slope evolution. It uses the concept of "erosivity" (generally, the relative ratio of driving and resisting forces) and slope angle to reshape an initial topography. Finally, it asks the students themselves to come up with a real-world situation worth modeling.

Locke, Bill

328

HYBRID RECEPTOR MODELING  

EPA Science Inventory

A hybrid receptor model is a specified mathematical procedure which uses not only the ambient species concentration measurements that form the input data for a pure receptor model, but in addition source emission rates or atmospheric dispersion or transformation information chara...

329

Models and Metaphors  

ERIC Educational Resources Information Center

Humanity delights in spinning conceptual models of the world. These models, in turn, mirror their respective root metaphors. Three root metaphors--spiritual, organic, and mechanical--have dominated western thought. The spiritual metaphor runs from Plato, through Hegel, and connects with Montessori. The organic metaphor extends from Aristotle,…

Ivie, Stanley D.

2007-01-01

330

Make a Model Caldera  

NSDL National Science Digital Library

In this quick activity (page 2 of PDF), learners will model how large depressions near the top of a volcano are formed by using an inflating and deflating balloon submerged in flour. The model illustrates how volcanic ground swells and collapses as pressure builds and drains from a magma reservoir. Relates to the linked video, DragonflyTV GPS: Lava Flow.

Twin Cities Public Television, Inc.

2007-01-01

331

MULTIMEDIA EXPOSURE MODELING  

EPA Science Inventory

This task addresses a number of issues that arise in multimedia modeling with an emphasis on interactions among the atmosphere and multiple other environmental media. Approaches for working with multiple types of models and the data sets are being developed. Proper software tool...

332

Model Organisms and Arabidopsis  

NSDL National Science Digital Library

Lesson plan with three parts. First part is to get students thinking about the types of organism used by research scientists. The second describes characteristics of a model plant. The third part describes the Arabidopsis as a model plant for research scientists.

Dr. John Kowalski (Roanoke Valley GovernorÂ?s School for Science and Technology)

2007-07-16

333

Context modeling and reasoning  

E-print Network

Applications Sentient Computing Smart * (Room, Space, Factory, ...) #12;Context-aware applications #12;10 User, Context-aware Applications (SFB 627)Universität Stuttgart #12;2 SFB 627 (Nexus): World Models for Mobile Context-Aware Systems Goals: Methods to realize global world model Innovative context-aware applications

Appelrath, Hans-JĂĽrgen

334

Macroscopic Models of Superconductivity  

E-print Network

Macroscopic Models of Superconductivity S. J. Chapman, St. Catherine's College, Oxford. Thesis-boundary model for the destruction of superconductivity by an applied magnetic field, under isothermal then describe the Ginzburg-Landau theory of superconductivity, in which the sharp interface is `smoothed out

Chapman, Jon

335

Modeling Microbial Growth  

NSDL National Science Digital Library

Is bacterial growth always exponential? Do bacteria with the fastest rate of growth always have the largest populations? Biota models offer extended opportunities to observe population growth over time. What are the factors that affect growth? Explore continuous, chaotic, and cyclic growth models. * examine the dynamics of growth for populations of virtual bacteria with differing growth rates and carrying capacities

Ethel D. Stanley (Beloit College; Biology)

2006-05-20

336

Stiff magnetofluid cosmological model  

SciTech Connect

We investigate the behavior of the magnetic field in a cosmological model filled with a stiff perfect fluid in general relativity. The magnetic field is due to an electric current along the x axis. The behavior of the model when a magnetic field is absent is also discussed.

Bali, R.; Tyagi, A.

1988-05-01

337

Geothermal Power Plant Model  

NSDL National Science Digital Library

In this activity, learners make a model of a power plant that uses steam. Learners use simple materials like foil, a tin can, and a pot of water to model a geothermal power plant. Learners use a pinwheel to observe the power produced by the steam. SAFETY NOTE: Adult assistance required.

Commission, California E.

2006-01-01

338

Multiplying Fractions (Area Model)  

NSDL National Science Digital Library

In this teaching idea, students will learn how to use the area model to find the product when two fractions are multiplied. NOTE: Click the Download link on the right side of the screen to display the lesson without ads and to view the graphic example of the model.

Page, Audrey P.

2012-04-22

339

The quark bag model  

Microsoft Academic Search

The quark bag model is reviewed here with particular emphasis on spectroscopic applications and the discussion of exotic objects as baryonium, gluonium, and the quark phase of matter. The physical vacuum is pictured in the model as a two-phase medium. In normal phase of the vacuum, outside hadrons, the propagation of quark and gluon fields is forbidden. When small bubbles

Peter Hasenfratz; Julius Kuti

1978-01-01

340

Video Self-Modeling  

ERIC Educational Resources Information Center

Video self-modeling (VSM) first appeared on the psychology and education stage in the early 1970s. The practical applications of VSM were limited by lack of access to tools for editing video, which is necessary for almost all self-modeling videos. Thus, VSM remained in the research domain until the advent of camcorders and VCR/DVD players and,…

Buggey, Tom; Ogle, Lindsey

2012-01-01

341

A Model for Neurolinguistics.  

ERIC Educational Resources Information Center

Noting that linguistics and the neurological sciences have developed independently, this paper presents a coordinated approach to man's understanding of language, cognition, and mind. A neurological model is developed following a discussion of the rationale of such an approach. Chapters include: (1) the relation of neurological evidence to models

Whitaker, H. A.

342

Structural Equation Model Trees  

ERIC Educational Resources Information Center

In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree…

Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

2013-01-01

343

MCMC Estimation Multilevel Models  

E-print Network

.g. MLwiN, BayesX Restricted General Purpose e.g. WinBUGS General purpose e.g. Fortran, C, C++ #12;An We will t a random slopes regression model to data #12;Setting up a Model using IGLS The Equations

Browne, William

344

Parsimony and Model Evaluation.  

ERIC Educational Resources Information Center

Argues that H. W. Marsh and K.-T. Hau (1996) misunderstood parsimony and its role in testing a hypothesis about an incompletely specified model to establish its objective validity. More parsimonious models represent more complete hypotheses having more ways of being tested and confirmed. Marsh and Hau could also have used more parsimonious…

Mulaik, Stanley A.

1998-01-01

345

Industrial Mathematics Modeling Workshop  

E-print Network

: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : v Maximizing the Deflection to Voltage Ratio in a Circular Piezoelectric Actuator Design Chad Bouton) : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1 Modeling of the Radius of Curvature for THUNDER Actuators Bryan Cunningham, Karla Mossi and Norvell Rose (FACE International Corp.) : : : : : 11 Mathematical Modeling of High Power Amplifier (HPA

346

MODELING WATER QUALITY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Water quality models are based on some representation of hydrology and may include movement of surface water, ground water, and mixing of water in lakes and water bodies. Water quality models simulate some combination of sediment, nutrients, heavy metals, xenobiotics, and aquatic biology. Althoug...

347

Model Children's Code.  

ERIC Educational Resources Information Center

The Model Children's Code was developed to provide a legally correct model code that American Indian tribes can use to enact children's codes that fulfill their legal, cultural and economic needs. Code sections cover the court system, jurisdiction, juvenile offender procedures, minor-in-need-of-care, and termination. Almost every Code section is…

New Mexico Univ., Albuquerque. American Indian Law Center.

348

Cascaded Markov Models  

Microsoft Academic Search

This paper presents a new approach to partial parsing of context-free structures. The approach is based on Markov Models. Each layer of the resulting structure is represented by its own Markov Model, and output of a lower layer is passed as input to the next higher layer. An empirical evaluation of the method yields very good results for NP\\/PP chunking

Thorsten Brants

1999-01-01

349

Modeling the Night Sky  

NSDL National Science Digital Library

In this two-part activity, learners explore the Earth and Sun's positions in relation to the constellations of the ecliptic with a small model. Then they extend to explore the motions of the Earth and the inner planets in a larger classroom-size model.

Observatory, Mcdonald

2011-01-01

350

Modeling Diverse Communities of  

E-print Network

Modeling Diverse Communities of Marine Microbes Michael J. Follows and Stephanie Dutkiewicz Earth in the ocean are mediated by complex and diverse microbial communities. Over the past decade, marine ecosystem of marine microbial communities. These models begin to resolve, and address the significance of, diversity

Follows, Mick

351

Dual-Schemata Model  

NASA Astrophysics Data System (ADS)

In this paper, a new machine-learning method, called Dual-Schemata model, is presented. Dual-Schemata model is a kind of self-organizational machine learning methods for an autonomous robot interacting with an unknown dynamical environment. This is based on Piaget's Schema model, that is a classical psychological model to explain memory and cognitive development of human beings. Our Dual-Schemata model is developed as a computational model of Piaget's Schema model, especially focusing on sensori-motor developing period. This developmental process is characterized by a couple of two mutually-interacting dynamics; one is a dynamics formed by assimilation and accommodation, and the other dynamics is formed by equilibration and differentiation. By these dynamics schema system enables an agent to act well in a real world. This schema's differentiation process corresponds to a symbol formation process occurring within an autonomous agent when it interacts with an unknown, dynamically changing environment. Experiment results obtained from an autonomous facial robot in which our model is embedded are presented; an autonomous facial robot becomes able to chase a ball moving in various ways without any rewards nor teaching signals from outside. Moreover, emergence of concepts on the target movements within a robot is shown and discussed in terms of fuzzy logics on set-subset inclusive relationships.

Taniguchi, Tadahiro; Sawaragi, Tetsuo

352

Pathological Gambling: Psychiatric Models  

ERIC Educational Resources Information Center

Three psychiatric conceptual models: addictive, obsessive-compulsive spectrum and mood spectrum disorder have been proposed for pathological gambling. The objectives of this paper are to (1) evaluate the evidence base from the most recent reviews of each model, (2) update the evidence through 2007 and (3) summarize the status of the evidence for…

Westphal, James R.

2008-01-01

353

Automated Student Model Improvement  

ERIC Educational Resources Information Center

Student modeling plays a critical role in developing and improving instruction and instructional technologies. We present a technique for automated improvement of student models that leverages the DataShop repository, crowd sourcing, and a version of the Learning Factors Analysis algorithm. We demonstrate this method on eleven educational…

Koedinger, Kenneth R.; McLaughlin, Elizabeth A.; Stamper, John C.

2012-01-01

354

Dasymetric Modeling and Uncertainty  

PubMed Central

Dasymetric models increase the spatial resolution of population data by incorporating related ancillary data layers. The role of uncertainty in dasymetric modeling has not been fully addressed as of yet. Uncertainty is usually present because most population data are themselves uncertain, and/or the geographic processes that connect population and the ancillary data layers are not precisely known. A new dasymetric methodology - the Penalized Maximum Entropy Dasymetric Model (P-MEDM) - is presented that enables these sources of uncertainty to be represented and modeled. The P-MEDM propagates uncertainty through the model and yields fine-resolution population estimates with associated measures of uncertainty. This methodology contains a number of other benefits of theoretical and practical interest. In dasymetric modeling, researchers often struggle with identifying a relationship between population and ancillary data layers. The PEDM model simplifies this step by unifying how ancillary data are included. The P-MEDM also allows a rich array of data to be included, with disparate spatial resolutions, attribute resolutions, and uncertainties. While the P-MEDM does not necessarily produce more precise estimates than do existing approaches, it does help to unify how data enter the dasymetric model, it increases the types of data that may be used, and it allows geographers to characterize the quality of their dasymetric estimates. We present an application of the P-MEDM that includes household-level survey data combined with higher spatial resolution data such as from census tracts, block groups, and land cover classifications. PMID:25067846

Nagle, Nicholas N.; Buttenfield, Barbara P.; Leyk, Stefan; Speilman, Seth

2014-01-01

355

Modeling with Liapunov functions.  

NASA Technical Reports Server (NTRS)

Behavior of high-order linear control systems analyzed using liapunov second method, by finding low-order model with closely approximate response behavior of high order linear control systems analyzed, using Liapunov second method, by finding low order model with closely approximate response

Melsa, J. L.; Nordahl, D. M.

1967-01-01

356

The origin of modelling  

Microsoft Academic Search

Purpose – This paper aims to explore the relationship between modelling and design from a cybernetic perspective. Design\\/methodology\\/approach – Cybernetic understandings of the notions “modelling” and “design” are developed initially. The derived understandings are used to define an outline specification for a speculative design project based on an analysis and re-interpretation of an account from Pliny the Elder. The account

Phil Ayres

2007-01-01

357

ATMOSPHERIC MODEL DEVELOPMENT  

EPA Science Inventory

This task provides credible state of the art air quality models and guidance for use in implementation of National Ambient Air Quality Standards for ozone and PM. This research effort is to develop and improve air quality models, such as the Community Multiscale Air Quality (CMA...

358

Birth Weight Statistical Models  

E-print Network

Birth Weight Statistical Models -Generalized Linear Models- November, 2008 This exercise concerns the analysis of low birth weight data. This is of interest due to the fact that infant mortality rates and birth defect rates are very high for low birth weight babies. A woman's behavior during pregnancy

359

Thermal scale modeling  

NASA Technical Reports Server (NTRS)

Complex system study data indicate that factors associated with multilayer insulation pose major problem in scale modeling, that numerical analysis aids correction for known compromises of scaling criteria, and that probable errors in scale modeling experiments fall within range predicted by statistical analysis.

Mac Gregor, R. K.

1971-01-01

360

NEP systems model  

NASA Astrophysics Data System (ADS)

Various aspects of nuclear electric propulsion (NEP) systems analysis and modeling are discussed. The following specific topics are covered: (1) systems analysis challenges; (2) goals for NEP systems analysis; (3) the Nuclear Propulsion Office approach; and (4) NEP subsystem model development. The discussion is presented in vugraph form.

Gilland, Jim; George, Jeffrey A.

361

Computational Modeling of Tires  

NASA Technical Reports Server (NTRS)

This document contains presentations and discussions from the joint UVA/NASA Workshop on Computational Modeling of Tires. The workshop attendees represented NASA, the Army and Air force, tire companies, commercial software developers, and academia. The workshop objectives were to assess the state of technology in the computational modeling of tires and to provide guidelines for future research.

Noor, Ahmed K. (compiler); Tanner, John A. (compiler)

1995-01-01

362

Modeling the space shuttle  

Microsoft Academic Search

We summarize our methodology for modeling space shuttle processing using discrete event simulation. Why the project was initiated, what the overall goals were, how it was funded, and who were the members of the project team are identified. We describe the flow of the space shuttle flight hardware through the supporting infrastructure and how the-model was created to accurately portray

Grant R. Cates; Martin J. Steele; M. Mollaghasemi; G. Rabadi

2002-01-01

363

Sinusoids: Applications and Modeling  

NSDL National Science Digital Library

This demo actively involves students via the software simulations so that the determination of the sinusoidal model has a geometric flavor that complements the algebraic tools stressed in texts. This approach also introduces a modeling aspect since in some situations we may only be able to obtain a "close" approximation to the actual curve or data. Animations and Excel routines are included.

Roberts, Lila F.; Hill, David R.

2004-07-21

364

Model-Based Reasoning  

ERIC Educational Resources Information Center

In this paper, there will be a particular focus on mental models and their application to inductive reasoning within the realm of instruction. A basic assumption of this study is the observation that the construction of mental models and related reasoning is a slowly developing capability of cognitive systems that emerges effectively with proper…

Ifenthaler, Dirk; Seel, Norbert M.

2013-01-01

365

Modeling Water Filtration  

ERIC Educational Resources Information Center

Model-eliciting activities (MEAs) are not new to those in engineering or mathematics, but they were new to Melissa Parks. Model-eliciting activities are simulated real-world problems that integrate engineering, mathematical, and scientific thinking as students find solutions for specific scenarios. During this process, students generate solutions…

Parks, Melissa

2014-01-01

366

Foundations of biomolecular modeling.  

PubMed

The 2013 Nobel Prize in Chemistry has been awarded to Martin Karplus, Michael Levitt, and Arieh Warshel for "development of multiscale models for complex chemical systems." The honored work from the 1970s has provided a foundation for the widespread activities today in modeling organic and biomolecular systems. PMID:24315087

Jorgensen, William L

2013-12-01

367

Modeling Topics Kevin Gimpel  

E-print Network

Modeling Topics Kevin Gimpel December 11, 2006 Abstract Many applications in machine learning with text documents. In this review, we discuss techniques that use latent, topical information in text docu retrieval, topic tracking, novel event detection, document classification, and language modeling. In doing

Smith, Noah

368

Whole powder pattern modelling.  

PubMed

A new approach for the modelling of diffraction patterns without using analytical profile functions is described and tested on ball milled f.c.c. Ni powder samples. The proposed whole powder pattern modelling (WPPM) procedure allows a one-step refinement of microstructure parameters by a direct modelling of the experimental pattern. Lattice parameter and defect content, expressed as dislocation density, outer cut-off radius, contrast factor, twin and deformation fault probabilities), can be refined together with the parameters (mean and variance) of a grain-size distribution. Different models for lattice distortions and domain size and shape can be tested to simulate or model diffraction data for systems as different as plastically deformed metals or finely dispersed crystalline powders. TEM pictures support the conclusions obtained by WPPM and confirm the validity of the proposed procedure. PMID:11832590

Scardi, P; Leoni, M

2002-03-01

369

Neuroelectromagnetic forward modeling toolbox.  

PubMed

This paper introduces a Neuroelectromagnetic Forward Modeling Toolbox running under MATLAB (The Mathworks, Inc.) for generating realistic head models from available data (MRI and/or electrode locations) and for solving the forward problem of electro-magnetic source imaging numerically. The toolbox includes tools for segmenting scalp, skull, cerebrospinal fluid (CSF) and brain tissues from T1-weighted magnetic resonance (MR) images. After extracting the segmented tissue volumes, mesh generation can be performed using deformable models. When MR images are not available, it is possible to warp a template head model to measured electrode locations to obtain a better-fitting realistic model. The Boundary Element Method (BEM) is used for the numerical solution of the forward problem. Toolbox functions can be called from either a graphic user interface or from the command line. Function help messages and a tutorial are included. The toolbox is freely available under the GNU Public License for noncommercial use and open source development. PMID:19163587

Akalin Acar, Zeynep; Makeig, Scott

2008-01-01

370

Anisotropic Rabi model  

E-print Network

We define the anisotropic Rabi model as the generalization of the spin-boson Rabi model: The Hamiltonian system breaks the parity symmetry; the rotating and counter-rotating interactions are governed by two different coupling constants; a further parameter introduces a phase factor in the counter-rotating terms. The exact energy spectrum and eigenstates of the generalized model is worked out. The solution is obtained as an elaboration of a recent proposed method for the isotropic limit of the model. In this way, we provide a long sought solution of a cascade of models with immediate relevance in different physical fields, including i) quantum optics: two-level atom in single mode cross electric and magnetic fields; ii) solid state physics: electrons in semiconductors with Rashba and Dresselhaus spin-orbit coupling; iii) mesoscopic physics: Josephson junctions flux-qubit quantum circuits.

Qiong-Tao Xie; Shuai Cui; Jun-Peng Cao; Luigi Amico; Heng Fan

2014-05-20

371

Beyond the Standard Model  

SciTech Connect

These lectures constitute a short course in ``Beyond the Standard Model`` for students of experimental particle physics. The author discusses the general ideas which guide the construction of models of physics beyond the Standard model. The central principle, the one which most directly motivates the search for new physics, is the search for the mechanism of the spontaneous symmetry breaking observed in the theory of weak interactions. To illustrate models of weak-interaction symmetry breaking, the author gives a detailed discussion of the idea of supersymmetry and that of new strong interactions at the TeV energy scale. He discusses experiments that will probe the details of these models at future pp and e{sup +}e{sup {minus}} colliders.

Peskin, M.E.

1997-05-01

372

Model magnetosphere of Mercury  

NASA Technical Reports Server (NTRS)

A three-dimensional quantitative model of Mercury's magnetosphere based on Mariner 10 data is presented. The model assumes that the Mercury surface magnetic field consists of a dipole, a quadrupole, and an octupole. The dipole moment is determined, noting that the intensity of the quadrupole moment is 45% of the dipole, and that of the octupole moment is 29% of the dipole. The model meets four critical tests: (1) it produces the smallest residuals, (2) it can reproduce the crossing of a tail current sheet by Mariner 10, (3) all planetary field lines are confined inside the model magnetosphere, and (4) the size of the model agrees with the magnetopause crossings observed from Mariner 10. In addition, the plasma characteristics and regions of quiet and disturbed signatures observed from Mariner 10 are discussed.

Whang, Y. C.

1979-01-01

373

Strength Modeling Report  

NASA Technical Reports Server (NTRS)

Strength modeling is a complex and multi-dimensional issue. There are numerous parameters to the problem of characterizing human strength, most notably: (1) position and orientation of body joints; (2) isometric versus dynamic strength; (3) effector force versus joint torque; (4) instantaneous versus steady force; (5) active force versus reactive force; (6) presence or absence of gravity; (7) body somatotype and composition; (8) body (segment) masses; (9) muscle group envolvement; (10) muscle size; (11) fatigue; and (12) practice (training) or familiarity. In surveying the available literature on strength measurement and modeling an attempt was made to examine as many of these parameters as possible. The conclusions reached at this point toward the feasibility of implementing computationally reasonable human strength models. The assessment of accuracy of any model against a specific individual, however, will probably not be possible on any realistic scale. Taken statistically, strength modeling may be an effective tool for general questions of task feasibility and strength requirements.

Badler, N. I.; Lee, P.; Wong, S.

1985-01-01

374

VENTILATION MODEL REPORT  

SciTech Connect

The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their postclosure analyses.

V. Chipman

2002-10-31

375

Developing Climate Model Comparisons  

NASA Astrophysics Data System (ADS)

Since 1995, the worldwide climate modeling community has designed and participated in a series of intercomparison projects for the purposes of understanding and improving model performance, investigating scientific questions about the climate system, and projecting future climate conditions. These projects have been defined under the umbrella of the Coupled Model Intercomparison Project, and phase 6 of that project (CMIP6) is just getting under way. As in previous phases, many CMIP6 modeling activities interact and overlap with each other. For example, credible projections of future climate conditions require understanding and validating a variety of Earth system model responses, including those to changes in concentrations of greenhouse gases, aerosols and other air pollutants, and land use change.

O'Neill, Brian C.; Lamarque, Jean-Francois; Lawrence, David

2014-12-01

376

Modeling glacial climates  

NASA Technical Reports Server (NTRS)

Mathematical climate modelling has matured as a discipline to the point that it is useful in paleoclimatology. As an example a new two dimensional energy balance model is described and applied to several problems of current interest. The model includes the seasonal cycle and the detailed land-sea geographical distribution. By examining the changes in the seasonal cycle when external perturbations are forced upon the climate system it is possible to construct hypotheses about the origin of midlatitude ice sheets and polar ice caps. In particular the model predicts a rather sudden potential for glaciation over large areas when the Earth's orbital elements are only slightly altered. Similarly, the drift of continents or the change of atmospheric carbon dioxide over geological time induces radical changes in continental ice cover. With the advance of computer technology and improved understanding of the individual components of the climate system, these ideas will be tested in far more realistic models in the near future.

North, G. R.; Crowley, T. J.

1984-01-01

377

Kalman filter modeling  

NASA Technical Reports Server (NTRS)

The formulation of appropriate state-space models for Kalman filtering applications is studied. The so-called model is completely specified by four matrix parameters and the initial conditions of the recursive equations. Once these are determined, the die is cast, and the way in which the measurements are weighted is determined foreverafter. Thus, finding a model that fits the physical situation at hand is all important. Also, it is often the most difficult aspect of designing a Kalman filter. Formulation of discrete state models from the spectral density and ARMA random process descriptions is discussed. Finally, it is pointed out that many common processes encountered in applied work (such as band-limited white noise) simply do not lend themselves very well to Kalman filter modeling.

Brown, R. G.

1984-01-01

378

Protein Model Database  

SciTech Connect

The phenomenal success of the genome sequencing projects reveals the power of completeness in revolutionizing biological science. Currently it is possible to sequence entire organisms at a time, allowing for a systemic rather than fractional view of their organization and the various genome-encoded functions. There is an international plan to move towards a similar goal in the area of protein structure. This will not be achieved by experiment alone, but rather by a combination of efforts in crystallography, NMR spectroscopy, and computational modeling. Only a small fraction of structures are expected to be identified experimentally, the remainder to be modeled. Presently there is no organized infrastructure to critically evaluate and present these data to the biological community. The goal of the Protein Model Database project is to create such infrastructure, including (1) public database of theoretically derived protein structures; (2) reliable annotation of protein model quality, (3) novel structure analysis tools, and (4) access to the highest quality modeling techniques available.

Fidelis, K; Adzhubej, A; Kryshtafovych, A; Daniluk, P

2005-02-23

379

Molecular Dynamics Demonstration Model  

NSDL National Science Digital Library

The EJS Molecular Dynamics Demonstration model is constructed using the Lennard-Jones potential truncated at a distance of 3 molecular diameters. The motion of the molecules is governed by Newton's laws, approximated using the Verlet algorithm with the indicated Time step. For sufficiently small time steps dt, the system's total energy should be approximately conserved. Users can select various initial configurations using the drop down menu. Ejs Molecular Dynamics Demonstration model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the js_stp_md_MolecularDynamicsDemo.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for statistical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-11-15

380

XAFS Model Compound Library  

DOE Data Explorer

The XAFS Model Compound Library contains XAFS data on model compounds. The term "model" compounds refers to compounds of homogeneous and well-known crystallographic or molecular structure. Each data file in this library has an associated atoms.inp file that can be converted to a feff.inp file using the program ATOMS. (See the related Searchable Atoms.inp Archive at http://cars9.uchicago.edu/~newville/adb/) This Library exists because XAFS data on model compounds is useful for several reasons, including comparing to unknown data for "fingerprinting" and testing calculations and analysis methods. The collection here is currently limited, but is growing. The focus to date has been on inorganic compounds and minerals of interest to the geochemical community. [Copied, with editing, from http://cars9.uchicago.edu/~newville/ModelLib/

Newville, Matthew

381

Circular Membrane Modes Model  

NSDL National Science Digital Library

The Circular Membrane Modes model displays the analytical wave equation solution for an ideal circular membrane with a fixed boundary. The solution is described by two integers m and n where n is a positive integer that counts the number of radial nodes and m counts the number of azimuthal (angular) nodes. The model shows a time-dependent animation of the membrane displacement and Chladni-like nodal pattern. The Circular Membrane Modes model is a supplemental simulation for the article "Chladni Patterns on Drumheads: A Physics of Music Experiment" by Randy Worland in The Physics Teacher 49(1), 24-27 (2011) and has been approved by the authors and The Physics Teacher editor. The model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_mech_CircularMembraneModes.jar file will run the program if Java is installed.

Christian, Wolfgang

2010-10-11

382

Molecular Dynamics Model  

NSDL National Science Digital Library

The EJS Molecular Dynamics model is constructed using the Lennard-Jones potential truncated at a distance of 3 molecular diameters. The motion of the molecules is governed by Newton's laws, approximated using the Verlet algorithm with the indicated time step. For sufficiently small time steps dt, the system's total energy should be approximately conserved. The Molecular Dynamics model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_md_MolecularDynamics.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for classical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-11-16

383

Building a biomechanical model.  

PubMed

This article is based on an invited presentation at the Biomechanics Session for the Basic Science Focus Forum held at the Orthopaedic Trauma Association meeting, 2010. It is not intended to be a scientific presentation of any specific investigation. It presented aspects of several types of investigations to illustrate the variety of biomechanical models that are used, and what value can be derived from those models. All models have limitations in what they try to portray. In order for any model to provide useful information, it must stand some type of validation of its ability to behave similar to real world experiences. The advantages and disadvantages of each model must be described to the best of the investigators ability-so that the readers can determine how the information may be used in the real world. PMID:21768824

Latta, Loren; Milne, Edward L; Kaimrajh, David N

2011-08-01

384

Solar dynamo models  

NASA Astrophysics Data System (ADS)

Mean-field dynamo models and 3D magnetohydrodynamic (MHD) simulations of global-scale solar convection provide complementary insights into the origins of cyclic magnetic activity in the Sun. One particular class of mean-field dynamo models, known as the Babcock-Leighton Flux-Transport (BL-FT) modeling approach, has enjoyed much success recently in reproducing many aspects of the solar activity cycle. We review the essential ingredients of BL-FT models and we address whether these ingredients are consistent with convection simulations. Although BL-FT models appear to be robust enough to tolerate the variability of the meridional circulation found in convection simulations, they often neglect turbulent transport and dynamo processes within the bulk of the convective envelope. Current estimates of the efficiency of such processes from convection simulations suggest that this neglect is not justified.

Miesch, Mark S.

2008-10-01

385

Anisotropic Rabi model  

NASA Astrophysics Data System (ADS)

We define the anisotropic Rabi model as the generalization of the spin-boson Rabi model: The Hamiltonian system breaks the parity symmetry; the rotating and counterrotating interactions are governed by two different coupling constants; a further parameter introduces a phase factor in the counterrotating terms. The exact energy spectrum and eigenstates of the generalized model are worked out. The solution is obtained as an elaboration of a recently proposed method for the isotropic limit of the model. In this way, we provide a long-sought solution of a cascade of models with immediate relevance in different physical fields, including (i) quantum optics, a two-level atom in single-mode cross-electric and magnetic fields; (ii) solid-state physics, electrons in semiconductors with Rashba and Dresselhaus spin-orbit coupling; and (iii) mesoscopic physics, Josephson-junction flux-qubit quantum circuits.

Xie, Qiong-Tao; Cui, Shuai; Cao, Jun-Peng; Amico, Luigi; Fan, Heng

2014-04-01

386

Global ice sheet modeling  

SciTech Connect

The University of Maine conducted this study for Pacific Northwest Laboratory (PNL) as part of a global climate modeling task for site characterization of the potential nuclear waste respository site at Yucca Mountain, NV. The purpose of the study was to develop a global ice sheet dynamics model that will forecast the three-dimensional configuration of global ice sheets for specific climate change scenarios. The objective of the third (final) year of the work was to produce ice sheet data for glaciation scenarios covering the next 100,000 years. This was accomplished using both the map-plane and flowband solutions of our time-dependent, finite-element gridpoint model. The theory and equations used to develop the ice sheet models are presented. Three future scenarios were simulated by the model and results are discussed.

Hughes, T.J.; Fastook, J.L. [Univ. of Maine, Orono, ME (United States). Institute for Quaternary Studies

1994-05-01

387

Maximally Expressive Task Modeling  

NASA Technical Reports Server (NTRS)

Planning and scheduling systems organize "tasks" into a timeline or schedule. The tasks are defined within the scheduling system in logical containers called models. The dictionary might define a model of this type as "a system of things and relations satisfying a set of rules that, when applied to the things and relations, produce certainty about the tasks that are being modeled." One challenging domain for a planning and scheduling system is the operation of on-board experiment activities for the Space Station. The equipment used in these experiments is some of the most complex hardware ever developed by mankind, the information sought by these experiments is at the cutting edge of scientific endeavor, and the procedures for executing the experiments are intricate and exacting. Scheduling is made more difficult by a scarcity of space station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling space station experiment operations calls for a "maximally expressive" modeling schema. Modeling even the simplest of activities cannot be automated; no sensor can be attached to a piece of equipment that can discern how to use that piece of equipment; no camera can quantify how to operate a piece of equipment. Modeling is a human enterprise-both an art and a science. The modeling schema should allow the models to flow from the keyboard of the user as easily as works of literature flowed from the pen of Shakespeare. The Ground Systems Department at the Marshall Space Flight Center has embarked on an effort to develop a new scheduling engine that is highlighted by a maximally expressive modeling schema. This schema, presented in this paper, is a synergy of technological advances and domain-specific innovations.

Japp, John; Davis, Elizabeth; Maxwell, Theresa G. (Technical Monitor)

2002-01-01

388

Quantum Magnetism Analysis Model  

NSDL National Science Digital Library

The Quantum Magnetism Analysis Model was created to help students as well as researchers who are studying magnetism. It provides a very simple interface for defining (theoretical) quantum spin models; sliders are automatically created to vary the parameters in the models; and several plots are automatically created to visualize the results. Within the program, several measured (experimental) data sets are included for a variety of real molecules. These provide the opportunity to experience the modeling process by varying the parameters in the model and exploring how the simulated results compare to the measured data. The interactions between neighboring quantum magnetic moments ("spins") are modeled using the Heisenberg model; calculations are carried out by numerically diagonalizing the matrix representation of the Heisenberg Hamiltonian; and plots display the energy spectrum, magnetization, and magnetic susceptibility as a function of temperature and magnetic field. This simulation is a "Fully Integrated Tool for Magnetic Analysis in Research & Teaching," so we also refer to it with the acronym "FIT-MART". FIT-MART was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking ejs_fitmart.jar file will run the package if Java is installed. In future versions of this simulation, curricular materials will be included to help students to learn about magnetism, and automated fitting routines will be included to help researchers quickly and easily model experimental data. FIT-MART was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking ejs_fitmart.jar file will run the package if Java is installed.

Engelhardt, Larry; Garland, Chad; Rainey, Cameron; Freeman, Austin

2012-07-27

389

Spiral model pilot project information model  

NASA Technical Reports Server (NTRS)

The objective was an evaluation of the Spiral Model (SM) development approach to allow NASA Marshall to develop an experience base of that software management methodology. A discussion is presented of the Information Model (IM) that was used as part of the SM methodology. A key concept of the SM is the establishment of an IM to be used by management to track the progress of a project. The IM is the set of metrics that is to be measured and reported throughout the life of the project. These metrics measure both the product and the process to ensure the quality of the final delivery item and to ensure the project met programmatic guidelines. The beauty of the SM, along with the IM, is the ability to measure not only the correctness of the specification and implementation of the requirements but to also obtain a measure of customer satisfaction.

1991-01-01

390

7 Probabilistic Entity-Relationship Models, PRMs, and Plate Models  

Microsoft Academic Search

In this chapter, we introduce a graphical language for relational data called the probabilistic entity-relationship (PER) model. The model is an extension of the entity-relationship model, a common model for the abstract representation of database structure. We concentrate on the directed version of this model—the directed acyclic probabilistic entity-relationship (DAPER) model. The DAPER model is closely related to the plate

David Heckerman; Chris Meek; Daphne Koller

2004-01-01

391

Automatic Model Selection for Partially Linear Models  

PubMed Central

We propose and study a unified procedure for variable selection in partially linear models. A new type of double-penalized least squares is formulated, using the smoothing spline to estimate the nonparametric part and applying a shrinkage penalty on parametric components to achieve model parsimony. Theoretically we show that, with proper choices of the smoothing and regularization parameters, the proposed procedure can be as efficient as the oracle estimator (Fan and Li, 2001). We also study the asymptotic properties of the estimator when the number of parametric effects diverges with the sample size. Frequentist and Bayesian estimates of the covariance and confidence intervals are derived for the estimators. One great advantage of this procedure is its linear mixed model (LMM) representation, which greatly facilitates its implementation by using standard statistical software. Furthermore, the LMM framework enables one to treat the smoothing parameter as a variance component and hence conveniently estimate it together with other regression coefficients. Extensive numerical studies are conducted to demonstrate the effective performance of the proposed procedure. PMID:20160947

Ni, Xiao; Zhang, Daowen

2009-01-01

392

The North American Mercury Model Intercomparison Study (NAMMIS): Study description and model-to-model comparisons  

Microsoft Academic Search

An atmospheric mercury model intercomparison study has been conducted to compare three regional-scale atmospheric mercury models, CMAQ, REMSAD, and TEAM, in a tightly constrained testing environment with a focus on North America. Each of these models used the same horizontal modeling grid, pollutant emission information, modeled meteorology, and boundary conditions to the greatest extent practical. Three global-scale atmospheric mercury models

O. Russell Bullock; Dwight Atkinson; Thomas Braverman; Kevin Civerolo; Ashu Dastoor; Didier Davignon; Jia-Yeong Ku; Kristen Lohman; Thomas C. Myers; Christian Seigneur; Gopal Sistla; Krish Vijayaraghavan

2008-01-01

393

Animal models of asthma.  

PubMed

Animal models of asthma are a tool that allows studies to be conducted in the setting of an intact immune and respiratory system. These models have highlighted the importance of T-helper type 2 driven allergic responses in the progression of asthma and have been useful in the identification of potential drug targets for interventions involving allergic pathways. However, a number of drugs that have been shown to have some efficacy in animal models of asthma have shown little clinical benefit in human asthmatics. This may be due to a number of factors including the species of animal chosen and the methods used to induce an asthmatic phenotype in animals that do not normally develop a disease that could be characterized as asthma. The range of animal models available is vast, with the most popular models being rodents (inbred mice and rats) and guinea-pigs, which have the benefit of being easy to handle and being relatively cost effective compared with other models that are available. The recent advances in transgenic technology and the development of species-specific probes, particularly in mice, have allowed detailed mechanistic studies to be conducted. Despite these advances in technology, there are a number of issues with current animal models of asthma that must be recognized including the disparity in immunology and anatomy between these species and humans, the requirement for adjuvant during senitization in most models, the acute nature of the allergic response that is induced and the use of adult animals as the primary disease model. Some larger animal models using sheep and dogs have been developed that may address some of these issues but they also have different biology from humans in many ways and are extremely costly, with very few probes available for characterizing allergic responses in the airway in these species. As research in this area continues to expand, the relative merits and limitations of each model must be defined and understood in order to evaluate the information that is obtained from these models and to extrapolate these findings to humans so that effective drug therapies can be developed. Despite these issues, animal models have been, and will continue to be, vital in understanding the mechanisms that are involved in the development and progression of asthma. PMID:17581191

Zosky, G R; Sly, P D

2007-07-01

394

VPPA weld model evaluation  

NASA Astrophysics Data System (ADS)

NASA uses the Variable Polarity Plasma Arc Welding (VPPAW) process extensively for fabrication of Space Shuttle External Tanks. This welding process has been in use at NASA since the late 1970's but the physics of the process have never been satisfactorily modeled and understood. In an attempt to advance the level of understanding of VPPAW, Dr. Arthur C. Nunes, Jr., (NASA) has developed a mathematical model of the process. The work described in this report evaluated and used two versions (level-0 and level-1) of Dr. Nunes' model, and a model derived by the University of Alabama at Huntsville (UAH) from Dr. Nunes' level-1 model. Two series of VPPAW experiments were done, using over 400 different combinations of welding parameters. Observations were made of VPPAW process behavior as a function of specific welding parameter changes. Data from these weld experiments was used to evaluate and suggest improvements to Dr. Nunes' model. Experimental data and correlations with the model were used to develop a multi-variable control algorithm for use with a future VPPAW controller. This algorithm is designed to control weld widths (both on the crown and root of the weld) based upon the weld parameters, base metal properties, and real-time observation of the crown width. The algorithm exhibited accuracy comparable to that of the weld width measurements for both aluminum and mild steel welds.

McCutcheon, Kimble D.; Gordon, Stephen S.; Thompson, Paul A.

1992-07-01

395

Modeling the transition region  

NASA Technical Reports Server (NTRS)

The calculation of engineering flows undergoing laminar-turbulent transition presents special problems. Mean-flow quantities obey neither the fully laminar nor the fully turbulent correlations. In addition, local maxima in skin friction, wall temperature, and heat transfer often occur near the end of the transition region. Traditionally, modeling this region has been important for the design of turbine blades, where the transition region is long in relation to the chord length of the blade. More recently, the need for better transition-region models has been recognized by designers of hypersonic vehicles where the high Mach number, the low Reynolds number, and the low-disturbance flight environment emphasize the importance of the transition region. Needless to say, a model that might work well for the transitional flows typically found in gas turbines will not necessarily work well for the external surface of a hypersonic vehicle. In Section 2 of this report, some of the important flow features that control the transition region will be discussed. In Section 3, different approaches to the modeling problem will be summarized and cataloged. Fully turbulent flow models will be discussed in detail in Section 4; models specifically designed for transitional flow, in Section 5; and the evaluation of models, in Section 6.

Singer, Bart A.

1994-01-01

396

Phases of Moon Model  

NSDL National Science Digital Library

The EJS Phases of Moon model displays the appearance of Moon and how it changes depending on the position of Moon relative to Earth and Sun. The main window shows Earth (at the center) and Moon, as well as a circle tracing out Moon's orbit. Sun is far to the right in this picture and therefore the right side of Earth and Moon are bright while the left sides are dark. By using the Options Menu the Moon View window shows the appearance of Moon as seen from Earth when Moon is in the position shown in the main window. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. The EJS Phases of Moon model includes three supplemental documents (see below) that include a middle school lesson plan, a college level worksheet, and the student version of the program. EJS Phases of Moon model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_MoonPhases.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for astronomy are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Timberlake, Todd

2009-08-01

397

Modelling the Ultraviolet Sky  

NASA Astrophysics Data System (ADS)

A computer program is currently under development to model in 3D - one dimension of which is wavelength - all the known and major speculated sources of ultraviolet (1200 A - 3200 A) radiation over the celestial sphere. The software is being written in Fortran 77 and currently operates under IRIX; all output models are in FITS format. Models along with display software will become available to the astronomical community. An initial model of the UV zodiacal light together with point sources from the TD-1 source catalogue is presented. Also exhibited is the manner by which the software is operated at program run time and the overall program structure. The modelling is a five year development project: the work illustrated here represents product output at the end of year one. Future work includes improvements to the zodiacal light model and incorporation of the following models: diffuse Galactic light emission; Galactic molecular hydrogen fluorescence; Galactic highly ionized atomic line emission; integrated extra-galactic light; and speculated sources in the intergalactic medium such as ionized plasma and radiation from non-baryonic particle decay. This work is supported by United States Air Force Contract F19628-93-K-0004; and we are grateful for the encouragement of Dr Stephan Price.

Daniels, J.; Henry, R. C.; Murthy, J.; Allen, M.

1993-12-01

398

Functional Generalized Additive Models.  

PubMed

We introduce the functional generalized additive model (FGAM), a novel regression model for association studies between a scalar response and a functional predictor. We model the link-transformed mean response as the integral with respect to t of F{X(t), t} where F(·,·) is an unknown regression function and X(t) is a functional covariate. Rather than having an additive model in a finite number of principal components as in Müller and Yao (2008), our model incorporates the functional predictor directly and thus our model can be viewed as the natural functional extension of generalized additive models. We estimate F(·,·) using tensor-product B-splines with roughness penalties. A pointwise quantile transformation of the functional predictor is also considered to ensure each tensor-product B-spline has observed data on its support. The methods are evaluated using simulated data and their predictive performance is compared with other competing scalar-on-function regression alternatives. We illustrate the usefulness of our approach through an application to brain tractography, where X(t) is a signal from diffusion tensor imaging at position, t, along a tract in the brain. In one example, the response is disease-status (case or control) and in a second example, it is the score on a cognitive test. R code for performing the simulations and fitting the FGAM can be found in supplemental materials available online. PMID:24729671

McLean, Mathew W; Hooker, Giles; Staicu, Ana-Maria; Scheipl, Fabian; Ruppert, David

2014-01-01

399

VPPA weld model evaluation  

NASA Technical Reports Server (NTRS)

NASA uses the Variable Polarity Plasma Arc Welding (VPPAW) process extensively for fabrication of Space Shuttle External Tanks. This welding process has been in use at NASA since the late 1970's but the physics of the process have never been satisfactorily modeled and understood. In an attempt to advance the level of understanding of VPPAW, Dr. Arthur C. Nunes, Jr., (NASA) has developed a mathematical model of the process. The work described in this report evaluated and used two versions (level-0 and level-1) of Dr. Nunes' model, and a model derived by the University of Alabama at Huntsville (UAH) from Dr. Nunes' level-1 model. Two series of VPPAW experiments were done, using over 400 different combinations of welding parameters. Observations were made of VPPAW process behavior as a function of specific welding parameter changes. Data from these weld experiments was used to evaluate and suggest improvements to Dr. Nunes' model. Experimental data and correlations with the model were used to develop a multi-variable control algorithm for use with a future VPPAW controller. This algorithm is designed to control weld widths (both on the crown and root of the weld) based upon the weld parameters, base metal properties, and real-time observation of the crown width. The algorithm exhibited accuracy comparable to that of the weld width measurements for both aluminum and mild steel welds.

Mccutcheon, Kimble D.; Gordon, Stephen S.; Thompson, Paul A.

1992-01-01

400

Multiscale Cloud System Modeling  

NASA Technical Reports Server (NTRS)

The central theme of this paper is to describe how cloud system resolving models (CRMs) of grid spacing approximately 1 km have been applied to various important problems in atmospheric science across a wide range of spatial and temporal scales and how these applications relate to other modeling approaches. A long-standing problem concerns the representation of organized precipitating convective cloud systems in weather and climate models. Since CRMs resolve the mesoscale to large scales of motion (i.e., 10 km to global) they explicitly address the cloud system problem. By explicitly representing organized convection, CRMs bypass restrictive assumptions associated with convective parameterization such as the scale gap between cumulus and large-scale motion. Dynamical models provide insight into the physical mechanisms involved with scale interaction and convective organization. Multiscale CRMs simulate convective cloud systems in computational domains up to global and have been applied in place of contemporary convective parameterizations in global models. Multiscale CRMs pose a new challenge for model validation, which is met in an integrated approach involving CRMs, operational prediction systems, observational measurements, and dynamical models in a new international project: the Year of Tropical Convection, which has an emphasis on organized tropical convection and its global effects.

Tao, Wei-Kuo; Moncrieff, Mitchell W.

2009-01-01

401

SPAR Model Structural Efficiencies  

SciTech Connect

The Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute (EPRI) are supporting initiatives aimed at improving the quality of probabilistic risk assessments (PRAs). Included in these initiatives are the resolution of key technical issues that are have been judged to have the most significant influence on the baseline core damage frequency of the NRC’s Standardized Plant Analysis Risk (SPAR) models and licensee PRA models. Previous work addressed issues associated with support system initiating event analysis and loss of off-site power/station blackout analysis. The key technical issues were: • Development of a standard methodology and implementation of support system initiating events • Treatment of loss of offsite power • Development of standard approach for emergency core cooling following containment failure Some of the related issues were not fully resolved. This project continues the effort to resolve outstanding issues. The work scope was intended to include substantial collaboration with EPRI; however, EPRI has had other higher priority initiatives to support. Therefore this project has addressed SPAR modeling issues. The issues addressed are • SPAR model transparency • Common cause failure modeling deficiencies and approaches • Ac and dc modeling deficiencies and approaches • Instrumentation and control system modeling deficiencies and approaches

John Schroeder; Dan Henry

2013-04-01

402

Model for macroevolutionary dynamics  

PubMed Central

The highly skewed distribution of species among genera, although challenging to macroevolutionists, provides an opportunity to understand the dynamics of diversification, including species formation, extinction, and morphological evolution. Early models were based on either the work by Yule [Yule GU (1925) Philos Trans R Soc Lond B Biol Sci 213:21–87], which neglects extinction, or a simple birth–death (speciation–extinction) process. Here, we extend the more recent development of a generic, neutral speciation–extinction (of species)–origination (of genera; SEO) model for macroevolutionary dynamics of taxon diversification. Simulations show that deviations from the homogeneity assumptions in the model can be detected in species-per-genus distributions. The SEO model fits observed species-per-genus distributions well for class-to-kingdom–sized taxonomic groups. The model’s predictions for the appearance times (the time of the first existing species) of the taxonomic groups also approximately match estimates based on molecular inference and fossil records. Unlike estimates based on analyses of phylogenetic reconstruction, fitted extinction rates for large clades are close to speciation rates, consistent with high rates of species turnover and the relatively slow change in diversity observed in the fossil record. Finally, the SEO model generally supports the consistency of generic boundaries based on morphological differences between species and provides a comparator for rates of lineage splitting and morphological evolution. PMID:23781101

Maruvka, Yosef E.; Shnerb, Nadav M.; Kessler, David A.; Ricklefs, Robert E.

2013-01-01

403

Acute radiation risk models  

NASA Astrophysics Data System (ADS)

Biologically motivated mathematical models, which describe the dynamics of the major hematopoietic lineages (the thrombocytopoietic, lymphocytopoietic, granulocytopoietic, and erythropoietic systems) in acutely/chronically irradiated humans are developed. These models are implemented as systems of nonlinear differential equations, which variables and constant parameters have clear biological meaning. It is shown that the developed models are capable of reproducing clinical data on the dynamics of these systems in humans exposed to acute radiation in the result of incidents and accidents, as well as in humans exposed to low-level chronic radiation. Moreover, the averaged value of the "lethal" dose rates of chronic irradiation evaluated within models of these four major hematopoietic lineages coincides with the real minimal dose rate of lethal chronic irradiation. The demonstrated ability of the models of the human thrombocytopoietic, lymphocytopoietic, granulocytopoietic, and erythropoietic systems to predict the dynamical response of these systems to acute/chronic irradiation in wide ranges of doses and dose rates implies that these mathematical models form an universal tool for the investigation and prediction of the dynamics of the major human hematopoietic lineages for a vast pattern of irradiation scenarios. In particular, these models could be applied for the radiation risk assessment for health of astronauts exposed to space radiation during long-term space missions, such as voyages to Mars or Lunar colonies, as well as for health of people exposed to acute/chronic irradiation due to environmental radiological events.

Smirnova, Olga

404

Model compilation: An approach to automated model derivation  

NASA Technical Reports Server (NTRS)

An approach is introduced to automated model derivation for knowledge based systems. The approach, model compilation, involves procedurally generating the set of domain models used by a knowledge based system. With an implemented example, how this approach can be used to derive models of different precision and abstraction is illustrated, and models are tailored to different tasks, from a given set of base domain models. In particular, two implemented model compilers are described, each of which takes as input a base model that describes the structure and behavior of a simple electromechanical device, the Reaction Wheel Assembly of NASA's Hubble Space Telescope. The compilers transform this relatively general base model into simple task specific models for troubleshooting and redesign, respectively, by applying a sequence of model transformations. Each transformation in this sequence produces an increasingly more specialized model. The compilation approach lessens the burden of updating and maintaining consistency among models by enabling their automatic regeneration.

Keller, Richard M.; Baudin, Catherine; Iwasaki, Yumi; Nayak, Pandurang; Tanaka, Kazuo

1990-01-01

405

TUTORIAL: Validating biorobotic models  

NASA Astrophysics Data System (ADS)

Some issues in neuroscience can be addressed by building robot models of biological sensorimotor systems. What we can conclude from building models or simulations, however, is determined by a number of factors in addition to the central hypothesis we intend to test. These include the way in which the hypothesis is represented and implemented in simulation, how the simulation output is interpreted, how it is compared to the behaviour of the biological system, and the conditions under which it is tested. These issues will be illustrated by discussing a series of robot models of cricket phonotaxis behaviour. .

Webb, Barbara

2006-09-01

406

Dynamical model for thyroid  

NASA Astrophysics Data System (ADS)

Thyroid's main chemical reactions are employed to develop a mathematical model. The presented model is based on differential equations where their dynamics reflects many aspects of thyroid's behavior. Our main focus here is the well known, but not well understood, phenomenon so called as Wolff-Chaikoff effect. It is shown that the inhibitory effect of intake iodide on the rate of one single enzyme causes a similar effect as Wolff-Chaikoff. Besides this issue, the presented model is capable of revealing other complex phenomena of thyroid hormones homeostasis.

Rokni Lamooki, Gholam Reza; Shirazi, Amir H.; Mani, Ali R.

2015-05-01

407

Aviation Safety Simulation Model  

NASA Technical Reports Server (NTRS)

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

Houser, Scott; Yackovetsky, Robert (Technical Monitor)

2001-01-01

408

Nonlocal quark model  

SciTech Connect

A nonlocal quark model is described. Quarks are described by a virton field, existing as virtual states only. Hadrons are described by standard quantized fields and have experimentally observable masses. Hadrons are bound states of quarks. The model satisfies all axioms of relativistic quantum field theory and does not contain ultraviolet divergences. Hadron-quark interaction Lagrangians are introduced. The strong, electromagnetic, and weak decays of the pseudoscalar and vector mesons as well as the baryon octet and decuplet are considered. The model contains only two free parameters, which characterize the quark field. Good agreement with the experimental data is obtained.

Efimov, G.V.; Ivanov, M.A.

1981-09-01

409

DNA Jewelry Models  

NSDL National Science Digital Library

Making DNA Jewelry Models is a portion of a unit on molecular genetics. Using the directions for this hands-on activity/lab helps students construct a model of DNA to learn DNA structure and decode it to better understand protein synthesis. They also have an actual badge of their DNA literacy to wear or use. Whether a key ring, earrings, bracelet, or necklace, students from fourth grade through adult can do and enjoy this activity. (Even visually impaired students made a model using larger beads.)

BEGIN:VCARD VERSION:2.1 FN:Catherine Sheils Ross N:Sheils Ross; Catherine ORG:Berkley High School (retired-6/98) REV:2005-04-09 END:VCARD

1995-06-30

410

The Gaia Universe Model  

NASA Astrophysics Data System (ADS)

The ESA Gaia astrometric mission has been designed to create an extraordinarily precise 3D map of about one billion of stars throughout the Galaxy and beyond. The Gaia Universe Model provides the astronomical sources - with their 3D position, velocity, magnitude and physical parameters- required to generate the simulated data for the development and testing of the massive data reduction software. Different types of objects, both galactic and extra-galactic, are provided by the model, including normal stars, several types of variable stars, supernovae, unresolved stars or quasars. A full description of the Gaia Universe Model can be found in Robin et. al 2012 (Astronomy & Astrophysics, 453, A100).

Masana, E.; Luri, X.; Borrachero, R.; Robin, A.; Jordi, C.

2013-05-01

411

RNG and turbulence modeling  

NASA Astrophysics Data System (ADS)

The ReNormalization Group (RNG) theory involves approximations which neglect much of the complexity of turbulent flow. The Yakhot and Orszag method is explained in detail. The strengths and weaknesses of RNG turbulence models are outlined. The basic RNG theory of the forced Navier-Stokes equations and the calculation of the Kolmogorov constant are studied. The derivation of the RNG kappa epsilon equations, which should serve as a guide for the derivation of other turbulence models is examined. The asymptotic theory of infinite Reynolds number turbulence is described. Extensions of RNG models to finite Reynolds number flows are dealt with. The practical application of RNG results is given.

Smith, Leslie A.

412

Magnetized cosmological model  

SciTech Connect

The object of this paper is to investigate the behavior of the magnetic field in a cosmological model for perfect fluid distribution. The magnetic field is due to an electric current produced along the /chi/ axis. It is assumed that expansion (/theta/) in the model is proportional to sigma/sup 1//sub 1/, the eigenvalue of the shear tensor sigma /sup j/ /sub i/. The behavior of the model when the magnetic field tends to zero and other physical properties are also discussed.

Bali, R.

1986-07-01

413

Atmospheric and Oceanic Modeling  

NSDL National Science Digital Library

The numerical methods, formulation and parameterizations used in models of the circulation of the atmosphere and ocean will be described in detail. Widely used numerical methods will be the focus but we will also review emerging concepts and new methods. The numerics underlying a hierarchy of models will be discussed, ranging from simple GFD models to the high-end GCMs. In the context of ocean GCMs, we will describe parameterization of geostrophic eddies, mixing and the surface and bottom boundary layers. In the atmosphere, we will review parameterizations of convection and large scale condensation, the planetary boundary layer and radiative transfer.

Adcroft, Alistair; Emanuel, Kerry A., 1955-; Marshall, John

2007-04-07

414

Modeling Physics.org  

NSDL National Science Digital Library

This website contains a compilation of materials based on the Modeling Instruction pedagogical approach to teaching physics. It includes content support for teachers, model assessments, lab guides, student study guides, problems and solutions, and materials from professional physics education workshops. Materials are organized by fundamental models and encompass topics typically covered in an introductory physics curriculum. All resources are freely downloadable and may be reproduced for classroom use. The resources were developed for high school use but most are appropriate for use in Introductory Physics classes.

2007-12-03

415

Modeling EERE Deployment Programs  

SciTech Connect

The purpose of this report is to compile information and conclusions gathered as part of three separate tasks undertaken as part of the overall project, “Modeling EERE Deployment Programs,” sponsored by the Planning, Analysis, and Evaluation office within the Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE). The purpose of the project was to identify and characterize the modeling of deployment programs within the EERE Technology Development (TD) programs, address improvements to modeling in the near term, and note gaps in knowledge where future research is needed.

Cort, Katherine A.; Hostick, Donna J.; Belzer, David B.; Livingston, Olga V.

2007-11-08

416

Modeling Undertow Velocities  

NASA Astrophysics Data System (ADS)

The paper will present a theoretical model for the prediction of undertow velocity profiles in the surf zone due to near-normally incident waves. The waves may be periodic or narrow-banded random waves, and the beach may be plane or barred. The theoretical model consists of three components: (i) breaking wave model; (ii) surface roller model; and (iii) undertow velocity profile model. \\textit{The breaking wave model} (Tajima and Madsen, 2002) is based on the concept of an equivalent linear wave and predicts linear wave characteristics for shoaling, breaking and broken waves. Non-linear wave characteristics, e.g., near-bottom orbital velocity, are obtained from equivalent linear wave characteristics and local bottom slope through use of simple transform formulae. \\textit{The surface roller model} is based on the same principle as Dally et al. (1985), but differs from this by transferring only the potential energy lost from the wave motion into the surface roller and calculating the decay of surface roller energy using a decay coefficient equal to that obtained for the breaking wave dissipation model. \\textit{The undertow velocity profile model} assumes a linearly varying shear stress over the water depth combined with an assumed form of the turbulent eddy viscosity. The shear stress at the surface is obtained from the breaking wave and surface roller models, whereas the bottom shear stress is obtained from considerations of mass conservation, i.e., depth-integrated undertow velocity must equal the volume transport of waves and surface roller above trough level. The near-bottom undertow velocity is calculated at the edge of the wave-bottom boundary layer, from knowledge of near-bottom orbital velocity, bottom shear stress and bottom roughness, using the combined wave-current bottom boundary layer theory by Madsen (1994). Comparison of predicted and measured undertow velocity profiles are performed for periodic and random waves normally incident on plane and barred concrete beaches as well as random waves near-normally incident on barred movable bed beach profiles. In general the agreement between predicted and observed undertow velocities is excellent. It is shown that model predictions are fairly insensitive to the choice of turbulent eddy viscosity, which is the only adjustable quantity in the model.

Tajima, Y.; Madsen, O. S.

2002-12-01

417

Beyond Standard Model Physics  

SciTech Connect

There are many recent results from searches for fundamental new physics using the TeVatron, the SLAC b-factory and HERA. This talk quickly reviewed searches for pair-produced stop, for gauge-mediated SUSY breaking, for Higgs bosons in the MSSM and NMSSM models, for leptoquarks, and v-hadrons. There is a SUSY model which accommodates the recent astrophysical experimental results that suggest that dark matter annihilation is occurring in the center of our galaxy, and a relevant experimental result. Finally, model-independent searches at D0, CDF, and H1 are discussed.

Bellantoni, L.

2009-11-01

418

Noon Shadow Model  

NSDL National Science Digital Library

The Noon Shadow model shows the geometry of the shadow cast by a gnomon at noon.  Users can change the orientation of the gnomon as well as its latitude.  The height of the gnomon and its shadow length are displayed in Earth radius units. Noon Shadow model is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_Noon Shadow.jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the plot and selecting "Open EJS Model" from the pop-up menu item.

Christian, Wolfgang; Timberlake, Todd

2010-04-20

419

Component-specific modeling  

NASA Technical Reports Server (NTRS)

Accomplishments are described for the second year effort of a 3-year program to develop methodology for component specific modeling of aircraft engine hot section components (turbine blades, turbine vanes, and burner liners). These accomplishments include: (1) engine thermodynamic and mission models; (2) geometry model generators; (3) remeshing; (4) specialty 3-D inelastic stuctural analysis; (5) computationally efficient solvers, (6) adaptive solution strategies; (7) engine performance parameters/component response variables decomposition and synthesis; (8) integrated software architecture and development, and (9) validation cases for software developed.

Mcknight, R. L.

1985-01-01

420

Model Course: Security +  

NSDL National Science Digital Library

This site includes a model course from the CyberWatch Center. The site does not currently include any educational materials, but does provide a model framework for structuring a course on this topic. This course would cover the current risks to electronic data, as well as a structured way to address security problems. The course would provide a good starting point for students going on to study specialized security. A detailed course outline is included. Users must register to view the model course, but registration is free and easy.

421

Battery performance models in ADVISOR  

Microsoft Academic Search

This paper summarizes battery modeling capabilities in ADVISOR—the National Renewable Energy Laboratory’s advanced vehicle simulator written in the Matlab\\/Simulink environment. ADVISOR’s Matlab-oriented battery models consist of the following: (1) an internal resistance model, (2) a resistance–capacitance (RC) model, (3) a PNGV capacitance model, (4) a neural network (nnet) lead acid model, and (5) a fundamental lead acid battery model. For

V. H. Johnson

2002-01-01

422

Climate and atmospheric modeling studies  

NASA Technical Reports Server (NTRS)

The climate and atmosphere modeling research programs have concentrated on the development of appropriate atmospheric and upper ocean models, and preliminary applications of these models. Principal models are a one-dimensional radiative-convective model, a three-dimensional global model, and an upper ocean model. Principal applications were the study of the impact of CO2, aerosols, and the solar 'constant' on climate.

1992-01-01

423

A High Precision Prediction Model Using Hybrid Grey Dynamic Model  

ERIC Educational Resources Information Center

In this paper, we propose a new prediction analysis model which combines the first order one variable Grey differential equation Model (abbreviated as GM(1,1) model) from grey system theory and time series Autoregressive Integrated Moving Average (ARIMA) model from statistics theory. We abbreviate the combined GM(1,1) ARIMA model as ARGM(1,1)…

Li, Guo-Dong; Yamaguchi, Daisuke; Nagai, Masatake; Masuda, Shiro

2008-01-01

424

Hybrid Model of IRT and Latent Class Models.  

ERIC Educational Resources Information Center

This study developed a hybrid of item response theory (IRT) models and latent class models, which combined the strengths of each type of model. The primary motivation for developing the new model is to describe characteristics of examinees' knowledge at the time of the examination. Hence, the application of the model lies mainly in so-called…

Yamamoto, Kentaro

425

Limitations of the Black-Scholes model Stochastic volatility models  

E-print Network

Limitations of the Black-Scholes model Stochastic volatility models Fractional Brownian motion models Concluding remarks Beyond the Black-Scholes-Merton model Harry van Zanten (TU/e) Econophysics Lecture Leiden, November 5, 2009 Harry van Zanten (TU/e) Beyond the Black-Scholes-Merton model #12

van den Brink, Jeroen

426

Model Discrepancy in the Saturated Path Hydrology Model: Initial Analysis  

E-print Network

Model Discrepancy in the Saturated Path Hydrology Model: Initial Analysis Tom Fricker University discrepancy in the Saturated Path Hydrology Model (logSPM, Kuczera et al., 2006). The purpose). 1 #12;3 The Saturated Path Hydrology Model We consider the Saturated Path Hydrology Model (log

Oakley, Jeremy

427

Rapid SmartCode Modeling Procedural Modeling for Urban Environments  

E-print Network

Rapid SmartCode Modeling Procedural Modeling for Urban Environments Yoshihiro Kobayashi, Ph generate 3D digital urban models for presentation in a real-time Virtual Reality (VR) environment. Several image into a realistically textured and rendered a 3D urban model. Using this method, city models based

428

High School Students' Modeling Knowledge High School Students' Modeling Knowledge  

E-print Network

High School Students' Modeling Knowledge High School Students' Modeling Knowledge David Fortus of the authors. #12;High School Students' Modeling Knowledge Abstract Modeling is a core scientific practice. This study probed the modeling knowledge of high school students who had not any explicit exposure

429

Model Comparison of Bayesian Semiparametric and Parametric Structural Equation Models  

ERIC Educational Resources Information Center

Structural equation models have wide applications. One of the most important issues in analyzing structural equation models is model comparison. This article proposes a Bayesian model comparison statistic, namely the "L[subscript nu]"-measure for both semiparametric and parametric structural equation models. For illustration purposes, we consider…

Song, Xin-Yuan; Xia, Ye-Mao; Pan, Jun-Hao; Lee, Sik-Yum

2011-01-01

430

String from Veneziano model  

E-print Network

This article is about my memories from the discovery that the Veneziano model describes in fact interacting strings. I came to the understanding of that the dual or Veneziano model is really a model of strings independently of L. Susskind and Y. Nambu. A characteristic feature of my approach was that I used thinking of very high order "fishnet" or planar Feynman diagrams as the way of at first describing the development of the strings. A chain of constituents leads to planar diagrams dominating when only neighbours on the chain interact significantly. The article also mentions the works of Ziro Koba and mine about extending the Veneziano model first to five external particles - as Bardakci and Ruegg, Chan Tsou, and Goebel and Sakita also did - and subsequently to an arbitrary number n of external mesons.

H. B. Nielsen

2009-04-27

431

MULTIMOD Econometric Model  

NSDL National Science Digital Library

Designed by the International Monetary Fund (IMF), MULTIMOD is a modern, dynamic, multi-country macro model of the world economy designed to study the transmission of shocks across countries as well as the short-run and medium-run consequences of alternative monetary and fiscal policies. Country sub-models include the seven largest industrial countries--Canada, France, Germany, Italy, Japan, the UK, and the US--and an aggregate grouping of fourteen smaller industrial nations. Full documentation of the MULTIMOD's current variant, the Mark III Econometric Model, and its sub-models, and downloading instructions are provided as well as a bibliography of articles that either explain Multimod, apply it, or are part of its technical implementation.

1998-01-01

432

Modelling Immunological Memory  

E-print Network

Accurate immunological models offer the possibility of performing highthroughput experiments in silico that can predict, or at least suggest, in vivo phenomena. In this chapter, we compare various models of immunological memory. We first validate an experimental immunological simulator, developed by the authors, by simulating several theories of immunological memory with known results. We then use the same system to evaluate the predicted effects of a theory of immunological memory. The resulting model has not been explored before in artificial immune systems research, and we compare the simulated in silico output with in vivo measurements. Although the theory appears valid, we suggest that there are a common set of reasons why immunological memory models are a useful support tool; not conclusive in themselves.

Garret, Simon; Walker, Joanne; Wilson, William; Aickelin, Uwe

2010-01-01

433

Falling in Fluid Model  

NSDL National Science Digital Library

The Falling in Fluid model shows a sphere falling through a fluid. The sphere is acted on by gravitational, buoyant, and viscous drag forces acting at the interface between the fluid and the object. At high speed, the drag force is proportional to the square of the speed whereas at low speed it is proportional to the speed. These regimes are characterized by the Reynolds number and this model computes the viscous drag force using a phenomenological equation that depends on the Reynolds number. The Falling in Fluid model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_mech__fluids_FallingInFluid.jar file will run the program if Java is installed.

Christian, Wolfgang

2010-05-18

434

X-33 RCS model  

NASA Technical Reports Server (NTRS)

Part of the high pressure nitrogen system used for the 1% scale X-33 reaction control system model. Installed in the Unitary Plan Wind Tunnel for supersonic testing. In building 1251, test section #2.

1998-01-01

435

General Models in Histology  

NSDL National Science Digital Library

An article from HAPS-EDucator describing a number of general principles or models in Histology that can help students recognize recurring patterns in histology and reinforce the understanding of the physiological process.

Nina Zanetti (Siena College Department of Biology)

2005-12-01

436

Refining climate models  

ScienceCinema

Using dogwood trees, Oak Ridge National Laboratory researchers are gaining a better understanding of the role photosynthesis and respiration play in the atmospheric carbon dioxide cycle. Their findings will aid computer modelers in improving the accuracy of climate simulations.

Warren, Jeff; Iversen, Colleen; Brooks, Jonathan; Ricciuto, Daniel

2014-06-26

437

Pendulum Motion Model  

NSDL National Science Digital Library

The Pendulum Motion Model lets users change the length, mass, initial displacement, initial velocity and acceleration due to gravity of a thin rigid pendulum capable of rotating a full 360 degrees. DIfferent integration methods are provided.

David Joiner

438

Modelling pulmonary blood flow  

PubMed Central

Computational model analysis is a method that has been used widely to understand and interpret complexity of interactions in the pulmonary system. Pulmonary blood transport is a multi-scale phenomenon that involves scale-dependent structure and function, therefore requiring different model assumptions for the microcirculation and the arterial or venous flows. The blood transport systems interact with the surrounding lung tissue, and are dependent on hydrostatic pressure gradients, control of vasoconstriction, and the topology and material composition of the vascular trees. This review focuses on computational models that have been developed to study the different mechanisms contributing to regional perfusion of the lung. Different models for the microcirculation and the pulmonary arteries are considered, including fractal approaches and anatomically-based methods. The studies that are reviewed illustrate the different complementary approaches that can be used to address the same physiological question of flow heterogeneity. PMID:18434260

Tawhai, Merryn H.; Burrowes, Kelly S.

2008-01-01

439

Pinhole Camera Model  

NSDL National Science Digital Library

The Pinhole Camera Model demonstrates the operation of a pinhole camera. Light rays leaving the top and bottom on an object of height h pass through a pinhole and strike a flat screen. These rays travel in straight lines accord with the principles of geometric optics. Drag the object and observe the image on the camera screen. Simple geometry shows that the image is inverted and that the ratio of the image to object size (the magnification) is the same as the ratio of the image to object distance. The Pinhole Camera Model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.

Christian, Wolfgang

2012-04-20

440

Supersymmetric sigma models  

SciTech Connect

We begin to construct the most general supersymmetric Lagrangians in one, two and four dimensions. We find that the matter couplings have a natural interpretation in the language of the nonlinear sigma model.

Bagger, J.A.

1984-09-01

441

Orsted Initial Field Model  

NASA Technical Reports Server (NTRS)

Magnetic measurements taken by the Orsted satellite during geomagnetic quiet conditions around January 1, 2000 have been used to derive a spherical harmonic model of the Earth's magnetic field for epoch 2000.0. The maximum degree and order of the model is 19 for internal, and 2 for external, source fields; however, coefficients above degree 14 may not be robust. Such detailed models exist for only one previous epoch, 1980. Achieved rms misfit is 2 nT for the scalar intensity and 4 nT for the vector components perpendicular to the magnetic field. This model is of higher detail than the IGRF 2000, which for scientific purposes related to the Orsted mission it supersedes.

Olsen, N.; Holme, R.; Hulot, G.; Sabaka, T.; Neubert, T.; Toffner-Clausen, L.; Primdahl, F.; Jorgensen, J.; Leger, J.-M.; Barraclough, D.; Smith, David E. (Technical Monitor)

2000-01-01

442

Model Fundamentals - version 2  

NSDL National Science Digital Library

Model Fundamentals, part of the Numerical Weather Prediction Professional Development Series and the "NWP Training Series: Effective Use of NWP in the Forecast Process", describes the components of an NWP model and how they fit into the forecast development process. It also explores why parameterization of many physical processes is necessary in NWP models. The module covers background concepts and terminology necessary for learning from the other modules in this series on NWP. Back in 2000, the subject matter expert for this module was Dr. Ralph Petersen of the National Centers for Environmental Prediction, Environmental Modeling Center (NCEP/EMC). Revisions to the module were made in 2009 by Drs. Bill Bua and Stephen Jascourt, from the NWP team at UCAR/COMET.

Comet

2009-11-05

443

Cubic Spline Model  

NSDL National Science Digital Library

The Cubic Spline Model displays a cubic spline and its derivatives. The model constructs N third-order piecewise continuous polynomialz (cubic splines) that connect N data points (nodes) with unit separation. Polynomial coefficients are chosen such that the resulting curve and its first derivative are smooth at the nodes.   Users can drag the nodes and observe the resulting curve. Radio buttons display first and second derivative curves. Note that the second derivative curve consists of line segments because the second derivative of a piecewise cubic polynomial is a piecewise first order polynomial. The Cubic Spline Model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double click the ejs_math_CubicSplineDemo.jar file to run the program if Java is installed.

Christian, Wolfgang

2011-09-17

444

Aerosol lenses propagation model.  

PubMed

We propose a model based on the properties of cascading lenses modulation transfer function (MTF) to reproduce the irradiance of a screen illuminated through a dense aerosol cloud. In this model, the aerosol cloud is broken into multiple thin layers considered as individual lenses. The screen irradiance generated by these individual layers is equivalent to the point-spread function (PSF) of each aerosol lens. Taking the Fourier transform of the PSF as a MTF, we cascade the lenses MTF to find the cloud MTF. The screen irradiance is found with the Fourier transform of this MTF. We show the derivation of the model and we compare the results with the Undique Monte Carlo simulator for four aerosols at three optical depths. The model is in agreement with the Monte Carlo for all the cases tested. PMID:21886230

Tremblay, Grégoire; Roy, Gilles

2011-09-01

445

Local Coordinates Model  

NSDL National Science Digital Library

The Local Coordinates model displays the position of a star in local (Altitude/Azimuth) coordinates. The horizon is shown along with the four cardinal directions (N, E, S, and W). The latitude of the observer is set at 35.5 degrees which sets the location of the north celestial pole (teal) relative to the northern horizon. The position of the star can be changed by using the Altitude and Azimuth sliders. The Local Coordinates model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_Local Coordinates.jar file will run the program if Java is installed. EJS is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models.

Belloni, Mario; Timberlake, Todd

2010-01-02

446

Reversible Chemical Kinetics Model  

NSDL National Science Digital Library

The Reversible Chemical Kinetics Model illustrates the time evolution of a reversible chemical reaction, from a given set of initial reactants concentration until chemical equilibrium is reached. The concentrations are plotted against time and the respective numerical values are periodically displayed at the data Table. As chemical equilibrium is attained, the concentrations become constant, the reaction quotient (Q) equalizes the equilibrium constant and Gibbs's energy change (G/RT) approaches zero. The Reversible Chemical Kinetics Model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.

Fernandes, Fernando S.

2012-10-20

447

Mantle Convection Modeling  

NSDL National Science Digital Library

This research page provides links to two animations of modeled mantle convection, showing the progression of convection over millions of years. There are also links to other work and publications by the author.

Livnat, Yarden; Utah, University O.

448

Direct integration transmittance model  

NASA Technical Reports Server (NTRS)

A transmittance model was developed for the 200-2000/cm region for interpretation of high spectral resolution measurements of laboratory absorption and of planetary thermal emission. The high spectral resolution requires transmittances to be computed monochromatically by summing the contribution of individual molecular absorption lines. A magnetic tape atlas of H2O,O3, and CO2 molecular line parameters serves as input to the transmittance model with simple empirical representations used for continuum regions wherever suitable laboratory data exist. The theoretical formulation of the transmittance model and the computational procedures used for the evaluation of the transmittances are discussed. Application is demonstrated of the model to several homogenous path laboratory absorption examples.

Kunde, V. G.; Maguire, W. C.

1973-01-01

449

Radiative transfer models  

NASA Technical Reports Server (NTRS)

The purpose of this work was to assist with the development of analytical techniques for the interpretation of infrared observations. We have done the following: (1) helped to develop models for continuum absorption calculations for water vapor in the far infrared spectral region; (2) worked on models for pressure-induced absorption for O2 and N2 and their comparison with available observations; and (3) developed preliminary studies of non-local thermal equilibrium effects in the upper stratosphere and mesosphere for infrared gases. These new techniques were employed for analysis of balloon-borne far infrared data by a group at the Harvard-Smithsonian Center for Astrophysics. The empirical continuum absorption model for water vapor in the far infrared spectral region and the pressure-induced N2 absorption model were found to give satisfactory results in the retrieval of the mixing ratios of a number of stratospheric trace constituents from balloon-borne far infrared observations.

Horwitz, James L.

1992-01-01

450

Fluidized bed combustor modeling  

NASA Technical Reports Server (NTRS)

A general mathematical model for the prediction of performance of a fluidized bed coal combustor (FBC) is developed. The basic elements of the model consist of: (1) hydrodynamics of gas and solids in the combustor; (2) description of gas and solids contacting pattern; (3) kinetics of combustion; and (4) absorption of SO2 by limestone in the bed. The model is capable of calculating the combustion efficiency, axial bed temperature profile, carbon hold-up in the bed, oxygen and SO2 concentrations in the bubble and emulsion phases, sulfur retention efficiency and particulate carry over by elutriation. The effects of bed geometry, excess air, location of heat transfer coils in the bed, calcium to sulfur ratio in the feeds, etc. are examined. The calculated results are compared with experimental data. Agreement between the calculated results and the observed data are satisfactory in most cases. Recommendations to enhance the accuracy of prediction of the model are suggested.

Horio, M.; Rengarajan, P.; Krishnan, R.; Wen, C. Y.

1977-01-01

451

Circular Well Superposition Model  

NSDL National Science Digital Library

The Circular Well Superposition model displays the time evolution of the position-space wave function in an deep 2D circular well. The default configuration shows the first excited state with zero angular momentum. Additional eigenstates can be added using a button in the eigenstate coefficient table. A description of the quantum system and eigenstates, with questions for the students, are included. Circular Well Superpostion model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_qm_Superposition2DCircularWell.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Open Source Physics programs for quantum mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or EJS.

Christian, Wolfgang

2008-11-21

452

Refining climate models  

SciTech Connect

Using dogwood trees, Oak Ridge National Laboratory researchers are gaining a better understanding of the role photosynthesis and respiration play in the atmospheric carbon dioxide cycle. Their findings will aid computer modelers in improving the accuracy of climate simulations.

Warren, Jeff; Iversen, Colleen; Brooks, Jonathan; Ricciuto, Daniel

2012-10-31

453

Model-Based Inquiry  

NSDL National Science Digital Library

Model-Based Inquiry (MBI) is an emergent instructional strategy that is gaining acceptance among science educators. This approach to learning realistically mirrors the work of scientists, who develop and test hypotheses to construct more sophisticated und

Benjamin Allred

2010-11-01

454

Dietary Exposure Potential Model  

EPA Science Inventory

Existing food consumption and contaminant residue databases, typically products of nutrition and regulatory monitoring, contain useful information to characterize dietary intake of environmental chemicals. A PC-based model with resident database system, termed the Die...

455

Concave Mirror Model  

NSDL National Science Digital Library

The Concave Mirror Model shows three principal rays leaving a candle of height h and striking a concave mirror. The first ray is parallel to the optic axis and is reflected back through the focal point. The second ray strikes the mirror on the optic axis a distance h below the flame. The third ray passes through the focal point and reflects parallel to the optic axis. All three rays cross at the image location in accord with the small angle approximation and the principles of geometric optics. The Concave Mirror Model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.

Christian, Wolfgang; Franciscouembre

2012-05-23

456

Hypervolume Monte Carlo Model  

NSDL National Science Digital Library

The Hypervolume Monte Carlo Model implements microcanonical simulations by sampling the position and momentum spaces. Although it is strictly proven in the thermodynamic limit, HVMC works well with a relatively small number of molecules. In contrast to other algorithms for Monte Carlo simulations, HVMC does not involve previous integration over the momentum space or demons. It is the full non-deterministic counter part of the NVE molecular dynamics method, also providing speed distribution functions. Moreover, the method allows a straightforward simulation of the ideal gas. The Hypervolume Monte Carlo Model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.

Fernandes, Fernando S.

2012-12-04

457

Contact dynamics math model  

NASA Technical Reports Server (NTRS)

The Space Station Mechanism Test Bed consists of a hydraulically driven, computer controlled six degree of freedom (DOF) motion system with which docking, berthing, and other mechanisms can be evaluated. Measured contact forces and moments are provided to the simulation host computer to enable representation of orbital contact dynamics. This report describes the development of a generalized math model which represents the relative motion between two rigid orbiting vehicles. The model allows motion in six DOF for each body, with no vehicle size limitation. The rotational and translational equations of motion are derived. The method used to transform the forces and moments from the sensor location to the vehicles' centers of mass is also explained. Two math models of docking mechanisms, a simple translational spring and the Remote Manipulator System end effector, are presented along with simulation results. The translational spring model is used in an attempt to verify the simulation with compensated hardware in the loop results.

Glaese, John R.; Tobbe, Patrick A.

1986-01-01

458

Gaussian Multipole Model (GMM)  

PubMed Central

An electrostatic model based on charge density is proposed as a model for future force fields. The model is composed of a nucleus and a single Slater-type contracted Gaussian multipole charge density on each atom. The Gaussian multipoles are fit to the electrostatic potential (ESP) calculated at the B3LYP/6-31G* and HF/aug-cc-pVTZ levels of theory and tested by comparing electrostatic dimer energies, inter-molecular density overlap integrals, and permanent molecular multipole moments with their respective ab initio values. For the case of water, the atomic Gaussian multipole moments Qlm are shown to be a smooth function of internal geometry (bond length and bond angle), which can be approximated by a truncated linear Taylor series. In addition, results are given when the Gaussian multipole charge density is applied to a model for exchange-repulsion energy based on the inter-molecular density overlap. PMID:20209077

Elking, Dennis M.; Cisneros, G. Andrés; Piquemal, Jean-Philip; Darden, Thomas A.; Pedersen, Lee G.

2009-01-01

459

Modelling bursty time series  

NASA Astrophysics Data System (ADS)

Many human-related activities show power-law decaying interevent time distribution with exponents usually varying between 1 and 2. We study a simple task-queuing model, which produces bursty time series due to the non-trivial dynamics of the task list. The model is characterized by a priority distribution as an input parameter, which describes the choice procedure from the list. We give exact results on the asymptotic behaviour of the model and we show that the interevent time distribution is power-law decaying for any kind of input distributions that remain normalizable in the infinite list limit, with exponents tunable between 1 and 2. The model satisfies a scaling law between the exponents of interevent time distribution (?) and autocorrelation function (?): ? + ? = 2. This law is general for renewal processes with power-law decaying interevent time distribution. We conclude that slowly decaying autocorrelation function indicates long-range dependence only if the scaling law is violated.

Vajna, Szabolcs; Tóth, Bálint; Kertész, János

2013-10-01

460

Predator-Prey Models  

NSDL National Science Digital Library

Using Maple, Mathmatica, or MatLab, learner should be able to develop and explore the Lotka-Volterra model for predator-prey interactions as a prototypical first-order system of differential equations.

Smith, David

2001-01-30

461

Predator-Prey Models  

NSDL National Science Digital Library

Using Maple, Mathmatica, or MatLab, learner should be able to develop the Lotka-Volterra model for predator-prey interactions and a two-populaton version of Eulers Method for solving a system of differential equations.

Smith, David

2001-01-22

462

MODELING TREE LEVEL PROCESSES  

EPA Science Inventory

An overview of three main types of simulation approach (explanatory, abstraction, and estimation) is presented, along with a discussion of their capabilities limitations, and the steps required for their validation. A process model being developed through the Forest Response Prog...

463

Theoretical Leonid entry modeling  

SciTech Connect

In this work we present a model originally developed by ReVelle (1979, 1993) that has been applied to model large Leonid bolides with a few relatively minor modifications and one major modification which allows for catastrophic 'pancake: fragmentation processes as described below. The minor modifications include allowing the energy of ablation per unit mass for vaporization, Qvap, to be a free variable that is adjusted until agreement is obtained between the theoretical model and the statistically expected ablation coefficient for the Leonids (Group IIIB type bolide). It was found that the Qvap had to be reduced by a factor of about five times compared to the accepted value of Qvap for cometary materials. Alternative ways of achieving this degree of agreement between theory and observations are also suggested as well. In a separate paper we apply this model to a specific Leonid bolide during the 1998 storm period.

ReVelle, D. O. (Douglas O.)

2001-01-01

464

Minkowski Diagram Model  

NSDL National Science Digital Library

The Minkowski Diagram model displays the spacetime diagrams for two inertial observers. One or two events may be displayed and moved with the mouse. Optionally, the corresponding light cones may be shown, as well as the simultaneity lines in both reference frames. The spacetime interval is automatically computed. The simulation may be used to discuss simultaneity and causality in special relativity. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. The Minkowski Diagram model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_special_relativity_minkowski.jar file will run the program if Java is installed. Please note that this resource requires at least version 1.5 of Java (JRE).

Aguirregabiria, Juan

2011-09-09

465

Modeling Ionospheric Electrodynamics (Invited)  

NASA Astrophysics Data System (ADS)

We present modeling results of ionospheric electrodynamics using the 3D NRL ionosphere model SAMI3. Recently, SAMI3 has been upgraded to solve the potential equation that determines the electrostatic potential from the ionospheric conductances (Pedersen and Hall) and drivers: neutral wind, gravity, and parallel current systems. We present results showing the impact of different neutral wind models (e.g., HWM93, HWM07, TIMEGCM) on the dynamics of the low- to mid-latitude ionosphere, as well as the Region 1 and 2 current systems. We point out issues and concerns with obtaining an accurate specification of the global electric field within the context of existing models.(with J. Krall, G. Joyce, S. Slinker, and G. Crowley). Research supported by NASA and ONR

Huba, J. D.

2009-12-01

466

Maximally Expressive Modeling  

NASA Technical Reports Server (NTRS)

Planning and scheduling systems organize tasks into a timeline or schedule. Tasks are logically grouped into containers called models. Models are a collection of related tasks, along with their dependencies and requirements, that when met will produce the desired result. One challenging domain for a planning and scheduling system is the operation of on-board experiments for the International Space Station. In these experiments, the equipment used is among the most complex hardware ever developed; the information sought is at the cutting edge of scientific endeavor; and the procedures are intricate and exacting. Scheduling is made more difficult by a scarcity of station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling International Space Station experiment operations calls for a maximally expressive modeling schema.

Jaap, John; Davis, Elizabeth; Richardson, Lea

2004-01-01

467

Wire and column modeling  

E-print Network

problem in computer graphics. In this thesis, we have developed two methods for interactively modeling such shapes. Both methods developed create perforated shapes by building a framework of tube like elements, such that each edge of a given mesh...

Mandal, Esan

2004-09-30

468

The Tilt Intonation Model   

E-print Network

The tilt intonation model facilitates automatic analysis and synthesis of intonation. The analysis algorithm detects intonational events in F0 contours and parameterises them in terms of the continuously varying parameters. ...

Taylor, Paul

469

Rodent models of glaucoma  

PubMed Central

Glaucoma is a progressive, age-related optic neuropathy and a leading cause of irreversible blindness in the world. Animal models of glaucoma are essential to our continued efforts of elucidating the natural course of the disease and to developing therapeutic interventions to halt or reverse the progression of the condition. Over the past 10–15 years, rodents have become a popular model organism in which to study glaucoma, because of their high degree of availability, relatively low cost, short life-span, and amenability to experimental and genetic manipulation. In this review, we examine the numerous in vivo and in vitro rodent models of glaucoma, discuss the methods used to generate them, summarize some of the major findings obtained in these models, and identify individual strengths and weaknesses for the various systems. PMID:19379796

Johnson, Thomas V.; Tomarev, Stanislav I.

2010-01-01

470

Nonlinear ? model on supergroup  

NASA Astrophysics Data System (ADS)

The geometry of nonlinear ? models on supergroup manifolds is studied in the Riemannian formalism, we will show that the argument of Braaten. Curtright and Zachos can be extended to the parallelism of supergroup manifold.

Kobayashi, K.

1986-12-01

471

Teaching With Models  

NSDL National Science Digital Library

Created by Bob MacKay, Clark College "Scientific practice involves the construction, validation and application of scientific models, so science instruction should be designed to engage students in making and ...

Mackay, Bob

472

Fermi Paper Model (Formerly GLAST Paper Model)  

NSDL National Science Digital Library

This paper model provides a short description of the scientific instruments on board GLAST as well as links to other resources about the GLAST instruments. There is also a short description of how GLAST detects gamma-rays with the Large Area Telescope as well as the GLAST Burst Monitor detectors. The product includes three pages of parts that can be cut out and easily assembled using common household items. Note: In 2008, the Gamma-ray Large Area Space Telescope (GLAST) was renamed Fermi, for the physicist Enrico Fermi.

2009-01-01

473

Argentina corn yield model  

NASA Technical Reports Server (NTRS)

A model based on multiple regression was developed to estimate corn yields for the country of Argentina. A meteorological data set was obtained for the country by averaging data for stations within the corn-growing area. Predictor variables for the model were derived from monthly total precipitation, average monthly mean temperature, and average monthly maximum temperature. A trend variable was included for the years 1965 to 1980 since an increasing trend in yields due to technology was observed between these years.

Callis, S. L.; Sakamoto, C.

1984-01-01

474

The Protein Model Portal  

Microsoft Academic Search

Structural Genomics has been successful in determining the structures of many unique proteins in a high throughput manner.\\u000a Still, the number of known protein sequences is much larger than the number of experimentally solved protein structures. Homology\\u000a (or comparative) modeling methods make use of experimental protein structures to build models for evolutionary related proteins.\\u000a Thereby, experimental structure determination efforts and

Konstantin Arnold; Florian Kiefer; Jürgen Kopp; James N. D. Battey; Michael Podvinec; John D. Westbrook; Helen M. Berman; Lorenza Bordoli; Torsten Schwede

2009-01-01

475

CME Theory and Models  

Microsoft Academic Search

This chapter provides an overview of current efforts in the theory and modeling of CMEs. Five key areas are discussed: (1)\\u000a CME initiation; (2) CME evolution and propagation; (3) the structure of interplanetary CMEs derived from flux rope modeling;\\u000a (4) CME shock formation in the inner corona; and (5) particle acceleration and transport at CME driven shocks. In the section

T. G. Forbes; J. A. Linker; J. Chen; C. Cid; J. Kóta; M. A. Lee; G. Mann; Z. Mikic; M. S. Potgieter; J. M. Schmidt; G. L. Siscoe; R. Vainio; S. K. Antiochos; P. Riley

2006-01-01

476

Car Race Model  

NSDL National Science Digital Library

The Car Race model allows the classic physics scenario in kinematics of a car with a lead and a constant velocity racing a car with a constant acceleration. The Car Race was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_addition.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-28

477

Superior Ptolemaic Model  

NSDL National Science Digital Library

The Ejs Superior Ptolemaic model illustrates Ptolemy's orbit for a superior planet. The model consists of a deferent circle, centered on a point some distance from Earth (at the eccentric point). Attached to this deferent is the center of another circle, the epicycle. The center of the epicycle moves around the deferent with constant angular speed as seen from the equant point, which is exactly opposite the center of the deferent from Earth (so the center of the epicycle does not move at constant speed along the deferent). The planet moves along the epicycle at constant speed. This model is capable of reproducing retrograde motion and variations in the planet's brightness. It can also reproduce variations in the apparent size and spacing of the retrograde arcs. In this simulation the planet is assumed to move in the plane of the ecliptic, so its latitude is always zero. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. Ejs Superior Ptolemaic model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_SuperiorPtolemaic.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for astronomy are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Timberlake, Todd

2009-08-19

478

Fire: Modeling Probability  

NSDL National Science Digital Library

This lesson is designed to develop students' knowledge of simulations and modeling by experimenting with a simulated forest fire. This lesson provides links to discussions and activities related to modeling as well as suggested ways to integrate them into the lesson. Finally, the lesson provides links to follow-up lessons designed for use in succession with the current one. Note, reading level is not indicated because the lesson does not include student reading material.

2010-01-01

479

Modeling using optimization routines  

NASA Technical Reports Server (NTRS)

Modeling using mathematical optimization dynamics is a design tool used in magnetic suspension system development. MATLAB (software) is used to calculate minimum cost and other desired constraints. The parameters to be measured are programmed into mathematical equations. MATLAB will calculate answers for each set of inputs; inputs cover the boundary limits of the design. A Magnetic Suspension System using Electromagnets Mounted in a Plannar Array is a design system that makes use of optimization modeling.

Thomas, Theodore

1995-01-01

480

Improved steamflood analytical model  

E-print Network

two field cases, a 45x23x8 model was used that represented 1/8 of a 10-acre 5-spot pattern unit, using typical rock and reservoir fluid properties. In the SPE project case, three models were used: 23x12x12 (2.5 ac), 31x16x12 (5 ac) and 45x23x8 (10 ac...

Chandra, Suandy

2006-10-30

481

The Standard Model.  

PubMed

The Standard Model is the theory used to describe the interactions between fundamental particles and fundamental forces. It is remarkably successful at predicting the outcome of particle physics experiments. However, the theory has not yet been completely verified. In particular, one of the most vital constituents, the Higgs boson, has not yet been observed. This paper describes the Standard Model, the experimental tests of the theory that have led to its acceptance and its shortcomings. PMID:22253237

Shears, Tara

2012-02-28

482

Theory Modeling and Simulation  

SciTech Connect

Los Alamos has a long history in theory, modeling and simulation. We focus on multidisciplinary teams that tackle complex problems. Theory, modeling and simulation are tools to solve problems just like an NMR spectrometer, a gas chromatograph or an electron microscope. Problems should be used to define the theoretical tools needed and not the other way around. Best results occur when theory and experiments are working together in a team.

Shlachter, Jack [Los Alamos National Laboratory

2012-08-23

483

Deformable and Functional Models  

Microsoft Academic Search

\\u000a This article summarizes most of the material on deformable and functional models that the author covered in an invited plenary\\u000a lecture presented at the 2009 VIPIMAGE Conference. Following the organization of the presentation, the first part of the article\\u000a reviews deformable models, particularly, active contours and surfaces, topologically-adaptive active contours and surfaces,\\u000a and deformable organisms, focusing on their applications in

Demetri Terzopoulos

484

Ion Thruster Performance Model.  

NASA Astrophysics Data System (ADS)

A model of ion thruster performance is developed for high flux density cusped magnetic field thruster designs. This model is formulated in terms of the average energy required to produce an ion in the discharge chamber plasma and the fraction of these ions that are extracted to form the beam. The direct loss of high energy (primary) electrons from the plasma to the anode is shown to have a major effect on thruster performance. The model provides simple algebraic equations enabling one to calculate the beam ion energy cost, the average discharge chamber plasma ion energy cost, the primary electron density, the primary-to-Maxwellian electron density ratio and the Maxwellian electron temperature. Experiments indicate that the model correctly predicts the variation in plasma ion energy cost for changes in propellant gas (Ar, Kr and Xe), grid transparency to neutral atoms, beam extraction area, discharge voltage, and discharge chamber wall temperature. The model and experiments indicate that thruster performance may be described in terms of only four thruster configuration dependent parameters and two operating parameters. The model also suggests that improved performance should be exhibited by thruster designs which extract a large fraction of the ions produced in the discharge chamber, which have good primary electron and neutral atom containment and which operate at high propellant flow rates. In addition, it suggests that hollow cathode efficiency becomes increasingly important to the discharge chamber performance as the discharge voltage is reduced. Finally, the utility of the model is mission analysis calculations is demonstrated. The model makes it easy to determine which changes in thruster design or operating parameters have the greatest effect on the payload fraction and/or mission duration.

Brophy, John Raymond

485

The GRAM-3 model  

NASA Technical Reports Server (NTRS)

The Global Reference Atmosphere Model (GRAM) is under continuous development and improvement. GRAM data were compared with Middle Atmosphere Program (MAP) predictions and with shuttle data. An important note: Users should employ only step sizes in altitude that give vertical density gradients consistent with shuttle-derived density data. Using too small a vertical step size (finer then 1 km) will result in what appears to be unreasonably high values of density shears but what in reality is noise in the model.

Justus, C. G.

1987-01-01

486

Modeling Earth's Climate  

NSDL National Science Digital Library

In this investigation, students will explore the question: What might the climate of the future be like? Students will use simple climate models to explore how greenhouse gases warm the planet. Using more complex models, students will explore the effect of albedo and learn how positive and negative feedback loops affect the overall temperature. Students will analyze the relative effects of positive and negative feedback to make a prediction for the future of Earth's climate.

Consortium, The C.

2011-12-11

487

Modeling piezoelectric actuators  

Microsoft Academic Search

The piezoelectric actuator (PEA) is a well-known device for managing extremely small displacements in the range from 10 pm to 100 ?m. When developing a control system for a piezo-actuated positioning mechanism, the actuator dynamics have to be taken into account. An electromechanical piezo model, based on physical principles, is presented in this paper. In this model, a first-order differential

H. J. M. T. S. Adriaens; W. L. De Koning; R. Banning

2000-01-01

488

A precipitation occurrence model  

Microsoft Academic Search

.  ?An imbedded renewal process as a model of precipitation occurrence is fairly well known. Data permitting verification of\\u000a assumptions determining such a model, for example independence and distribution of sojourn times, are available rather rarely,\\u000a however, due to problems with definition of a precipitation. An operational definition of a precipitation is obtained by associating\\u000a the precipitation occurrence with an opening

J. Mohapl

2002-01-01

489

Mathematical Modeling in Science  

NSDL National Science Digital Library

Creating mathematical models using spreadsheets can help high school students learn at deep levels in both science and mathematics, and give teachers an excellent opportunity to integrate these two disciplines. The project described in this article involves a melding of mathematical and scientific processes. The two scientific concepts explored involve physics, specifically Hooke's law and Newton's laws of heating and cooling, though the modeling described can be used in many places in the science curriculum.

Robert M. Horton

2005-07-01

490

Mental models of electricity  

NSDL National Science Digital Library

The mental models people use to think about the nature of electric current were investigated. Interviews, based on sequences of prediction-observation-explanation, were conducted with Brazilian secondary students, technical school students, teachers, engineers and practitioners who deal with electricity as part of their daily activities. Four models are reported, showing a possible pattern of progression which may be related to individual's acquisition of conceptual knowledge about electricity.

Borges, A. T.

2005-11-03

491

Solar radiation model  

Microsoft Academic Search

Solar radiation models for predicting the average daily and hourly global radiation, beam radiation and diffuse radiation are reviewed in this paper. Seven models using the Ĺngström–Prescott equation to predict the average daily global radiation with hours of sunshine are considered. The average daily global radiation for Hong Kong (22.3°N latitude, 114.3°E longitude) is predicted. Estimations of monthly average hourly

L. T. Wong; W. K. Chow

2001-01-01

492

Information Modeling: Concepts  

Microsoft Academic Search

The fundaments of OPC UA are data transport and information modeling. Compared to Classic OPC, the data transport was changed\\u000a to state-of-the-art, platform-independent, secure, and reliable technologies and the capabilities to model information are\\u000a highly improved. In Classic OPC, only “pure” data is provided, for example, the temperature measured by a temperature sensor.\\u000a The only information available to understand the

Wolfgang Mahnke; Stefan-Helmut Leitner

493

Doppler Effect JS Model  

NSDL National Science Digital Library

The Doppler Effect JS Model shows five different animations with different combinations of moving/stationary sources/detectors. The final animation shows what happens when a source exceeds the speed of sound. The Doppler Effect JS Model was developed using the Easy Java Simulations (EJS) version 5. It is distributed as a ready-to-run html page and requires only a browser with JavaScript support. It is also distributed as an ePub.

Kennedy, Matt; Dixon, Rachel

2014-07-02

494

A comparison of cloud models  

NASA Astrophysics Data System (ADS)

Five different cloud models are compared over a broad frequency range. They are the model of Gunn and East (1954), the model of Liebe et al. (1989), Staelin's (1966) model, Slobin's (1982) model, and the model of Altshuler and Marr (1989). A short tutorial review of the theoretical basis and limitations of each cloud model is included. It is shown that the models all tend to agree at frequencies below 40 GHz, and for light to medium cloud conditions; however, above 10 GHz and for heavy to very heavy clouds, the models diverge.

Gerace, G. C.; Smith, E. K.

1990-10-01

495

Learning planar ising models  

SciTech Connect

Inference and learning of graphical models are both well-studied problems in statistics and machine learning that have found many applications in science and engineering. However, exact inference is intractable in general graphical models, which suggests the problem of seeking the best approximation to a collection of random variables within some tractable family of graphical models. In this paper, we focus our attention on the class of planar Ising models, for which inference is tractable using techniques of statistical physics [Kac and Ward; Kasteleyn]. Based on these techniques and recent methods for planarity testing and planar embedding [Chrobak and Payne], we propose a simple greedy algorithm for learning the best planar Ising model to approximate an arbitrary collection of binary random variables (possibly from sample data). Given the set of all pairwise correlations among variables, we select a planar graph and optimal planar Ising model defined on this graph to best approximate that set of correlations. We present the results of numerical experiments evaluating the performance of our algorithm.

Johnson, Jason K [Los Alamos National Laboratory; Chertkov, Michael [Los Alamos National Laboratory; Netrapalli, Praneeth [STUDENT UT AUSTIN

2010-11-12

496

Seismic wave propagation modeling  

SciTech Connect

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). A hybrid, finite-difference technique was developed for modeling nonlinear soil amplification from three-dimensional, finite-fault radiation patters for earthquakes in arbitrary earth models. The method was applied to the 17 January 1994 Northridge earthquake. Particle velocities were computed on a plane at 5-km depth, immediately above the causative fault. Time-series of the strike-perpendicular, lateral velocities then were propagated vertically in a soil column typical of the San Fernando Valley. Suitable material models were adapted from a suite used to model ground motions at the US Nevada Test Site. The effects of nonlinearity reduced relative spectral amplitudes by about 40% at frequencies above 1.5 Hz but only by 10% at lower frequencies. Runs made with source-depth amplitudes increased by a factor of two showed relative amplitudes above 1.5 Hz reduced by a total of 70% above 1.5 Hz and 20% at lower frequencies. Runs made with elastic-plastic material models showed similar behavior to runs made with Masing-Rule models.

Jones, E.M. [Los Alamos National Lab., NM (US); Olsen, K.B. [Univ. of California, Santa Barbara, CA (US)

1998-12-31

497

Phases of Venus Model  

NSDL National Science Digital Library

The EJS Venus Phases model illustrates the phases of Venus as predicted by either the Copernican system of the Ptolemaic system (the Copernican system is the default). One window shows Earth, Sun, and Venus on its Copernican orbit. Venus is shown as a disk with the side facing the sun colored yellow (since it reflects the sun's light) and the other side colored dark gray (since that side is dark). Playing the simulation puts all moving objects (Venus and Earth/Sun) in motion. Another window shows what Venus would look at this position, when viewed from Earth through a telescope. A menu option displays another window showing Galileo's drawings of his telescope observations of Venus. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. EJS Phases of Venus model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_VenusPhases.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for astronomy are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Timberlake, Todd

2009-08-18

498

Causal Rasch models  

PubMed Central

Rasch's unidimensional models for measurement show how to connect object measures (e.g., reader abilities), measurement mechanisms (e.g., machine-generated cloze reading items), and observational outcomes (e.g., counts correct on reading instruments). Substantive theory shows what interventions or manipulations to the measurement mechanism can be traded off against a change to the object measure to hold the observed outcome constant. A Rasch model integrated with a substantive theory dictates the form and substance of permissible interventions. Rasch analysis, absent construct theory and an associated specification equation, is a black box in which understanding may be more illusory than not. Finally, the quantitative hypothesis can be tested by comparing theory-based trade-off relations with observed trade-off relations. Only quantitative variables (as measured) support such trade-offs. Note that to test the quantitative hypothesis requires more than manipulation of the algebraic equivalencies in the Rasch model or descriptively fitting data to the model. A causal Rasch model involves experimental intervention/manipulation on either reader ability or text complexity or a conjoint intervention on both simultaneously to yield a successful prediction of the resultant observed outcome (count correct). We conjecture that when this type of manipulation is introduced for individual reader text encounters and model predictions are consistent with observations, the quantitative hypothesis is sustained. PMID:23986726

Stenner, A. Jackson; Fisher, William P.; Stone, Mark H.; Burdick, Donald S.

2013-01-01

499

Zeeman Heartbeat Model  

NSDL National Science Digital Library

The Zeeman Heartbeat Model uses work in Catastrophe Theory to create a simulation of the heartbeat cycle. The heart is represented as a blue circle in phase space and travels from diastole to systole which are represented as the green circles. Cardiac muscle fiber length (x) is represented on the y-axis and electrochemical activity (b) is represented on the x-axis. The model calculates the heart rate (in beats per minute) and a variable called gamma which is intrinsic to the pacemaker. The model allows the user to adjust several variables, including muscle tension and the location of diastole and systole, to see how the heart rate is affected. Adjust tension by moving the slider at the top of the display or by manually entering a number into the field. Adjust the location of diastole and systole by either dragging them or entering values into the fields at the bottom of the display. The Zeeman Heartbeat Model was developed as a final project in a sophomore-level Computational Physics course (Phy 200) using the Easy Java JavaScript Simulation (EjsS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.

Murray, Tyler

2014-06-07

500

Model for Topological Fermions  

NASA Astrophysics Data System (ADS)

We introduce a model designed to describe charged particles as stable topological solitons of a field with values on the internal space S3. These solitons behave like particles with relativistic properties like Lorentz contraction and velocity dependence of mass. This mass is defined by the energy of the soliton. In this sense this model is a generalization of the Sine-Gordon model1(We do not chase the aim to give a four-dimensional generalization of Coleman's isomorphism between the Sine-Gordon model and the Thirring model which was shown in 2-dimensional space-time) from 1+1-dimensions to 3+1-dimensions, from S1 to S3. For large distances from the centre of solitons this model tends to a dual U(1)-theory with freely propagating electromagnetic waves. Already at the classical level it describes important effects, which usually have to be explained by quantum field theory, like particle-antiparticle annihilation and the running of the coupling.

Faber, M.