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

Scission-point model of nuclear fission based on deformed-shell effects  

Microsoft Academic Search

A static model of nuclear fission is proposed based on the assumption of statistical equilibrium among collective degrees of freedom at the scission point. The relative probabilities of formation of complementary fission fragment pairs are determined from the relative potential energies of a system of two nearly touching, coaxial spheroids with quadrupole deformations. The total potential energy of the system

B. D. Wilkins; E. P. Steinberg; R. R. Chasman

1976-01-01

2

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

E-print Network

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 within 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. On the example of the fission process 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.

F. A. Ivanyuk

2013-11-15

3

At and Beyond the Scission Point:. what can we Learn from Scission and Prompt Neutrons?  

NASA Astrophysics Data System (ADS)

Scission and prompt neutrons provide indirect clues of the physical processes at play near the scission point when the two fission fragments are finally and forever separated. A scission model based on the approximation of a sudden rupture of the neck between the two nascent fragments is presented. It is used to compute the average number of scission neutrons per fission event in the symmetric fission of 236U. Once the fragments are fully accelerated, they will release their intrinsic excitation energy by emitting so-called prompt neutrons and gamma-rays. Monte Carlo simulations of this evaporation process are presented in the case of the first-chance fission of 235U. Future developments expected in the arenas of experiment, theory and evaluation are discussed.

Talou, P.

2008-04-01

4

Statistical prescission point model of fission fragment angular distributions  

NASA Astrophysics Data System (ADS)

In light of recent developments in fission studies such as slow saddle to scission motion and spin equilibration near the scission point, the theory of fission fragment angular distribution is examined and a new statistical prescission point model is developed. The conditional equilibrium of the collective angular bearing modes at the prescission point, which is guided mainly by their relaxation times and population probabilities, is taken into account in the present model. The present model gives a consistent description of the fragment angular and spin distributions for a wide variety of heavy and light ion induced fission reactions.

John, Bency; Kataria, S. K.

1998-03-01

5

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

6

Energy partition in nuclear fission  

Microsoft Academic Search

A scission point model (two spheroid model TSM) including semi-empirical, temperature-dependent shell correction energies for deformed fragments at scission is presented. It has been used to describe the mass-asymmetry-dependent partition of the total energy release on both fragments from spontaneous and induced fission. Characteristic trends of experimental fragment energy and neutron multiplicity data as function of incidence energy in the

A. Ruben; H. Märten; D. Seeliger

1991-01-01

7

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

8

Fission fragment angular distribution in heavy-ion-induced fission with anomalous behavior  

NASA Astrophysics Data System (ADS)

Fission fragment angular distribution in heavy-ion-induced fission reactions is of particular importance. Transition state theory is provided to determine the angular distribution of fission fragments which includes standard saddle-point statistical and standard scission-point statistical models. The standard saddle-point statistical model was not able to reproduce the experimental fission fragment angular anisotropies for several heavy-ion-induced fission systems. In contrast to the standard saddle-point model, the standard scission-point statistical model was fairly successful in the prediction of angular anisotropy in heavy-ion-induced fission reaction systems with an anomalous behavior in angular anisotropy of fission fragments, but this model is not widely used as the standard saddle-point statistical model. In this research, a generalized model is introduced for the prediction of fission fragments angular anisotropy in the heavy-ion-induced fission reaction systems having an anomalous behavior. For this purpose, we study the N14,O16,F19+Th232;O16,F19+U238;Mg24,Si28,S32+Pb208;S32+Au197; and O16+Cm248 reaction systems. Finally, it is shown that the presented model is much more successful than previous models.

Soheyli, S.; Feizi, B.

2014-08-01

9

Effect of transients in nuclear fission on multiplicity of prescission neutrons  

E-print Network

Transients in the fission of highly excited nuclei are studied in the framework of the Langevin equation. Time-dependent fission widths are calculated which show that after the initial transients, a steady flow towards the scission point is established not only for nuclei which have fission barriers but also for nuclei which have no fission barrier. It is shown from a comparison of the transient time and the fission life time that fission changes from a diffusive to a transient dominated process over a certain transition region as a function of the spin of the fissioning nucleus. Multiplicities of prescission neutrons are calculated in a statistical model with as well as without a single swoop description of fission and they are found to differ in the transition region. We however find that the difference is marginal and hence a single swoop picture of fission though not strictly valid in the transition region can still be used in the statistical model calculations.

Gargi Chaudhuri; Santanu Pal

2002-04-19

10

Study of Fission Barrier Heights of Uranium Isotopes by the Macroscopic-Microscopic Method  

NASA Astrophysics Data System (ADS)

Potential energy surfaces of uranium nuclei in the range of mass numbers 229 through 244 are investigated in the framework of the macroscopic-microscopic model and the heights of static fission barriers are obtained in terms of a double-humped structure. The macroscopic part of the nuclear energy is calculated according to Lublin—Strasbourg-drop (LSD) model. Shell and pairing corrections as the microscopic part are calculated with a folded-Yukawa single-particle potential. The calculation is carried out in a five-dimensional parameter space of the generalized Lawrence shapes. In order to extract saddle points on the potential energy surface, a new algorithm which can effectively find an optimal fission path leading from the ground state to the scission point is developed. The comparison of our results with available experimental data and others' theoretical results confirms the reliability of our calculations.

Zhong, Chun-Lai; Fan, Tie-Shuan

2014-09-01

11

Niche Modeling: Model Evaluation  

E-print Network

Ecological niche modeling has become a very popular tool in ecological and biogeographic studies across broad extents. The tool is used in hundreds of publications each year now, but some fundamental aspects of the approach have seen a fair amount...

Peterson, A. Townsend

2012-08-29

12

Quantum Circuit Model Topological Model  

E-print Network

Quantum Circuit Model Topological Model Comparison of Models Topological Quantum Computation Eric Rowell Texas A&M University October 2010 Eric Rowell Topological Quantum Computation #12;Quantum Circuit Model Topological Model Comparison of Models Outline 1 Quantum Circuit Model Gates, Circuits

Rowell, Eric C.

13

Basic model Basic model  

E-print Network

Spearman's (1904) seminal paper on the American Journal of Psychology entitled "General Inteligente, British Journal of Mathematical and Statistical Psychology, 48, 211-220. 3 / 66 #12;Early days Basic model that Spearman invented factor analysis but his almost exclusive concern with the notion of a general factor

Liu, I-Shih

14

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...

15

Assessment models  

NASA Technical Reports Server (NTRS)

The types of models used in assessment of possible chemical perturbations to the stratosphere are reviewed. The statue of one and two dimensional models are discussed. The problem of model validation is covered before the status of photochemical modeling efforts is discussed. A hierarchy of tests for photochemical models is presented.

Pyle, J. A.; Butler, D. M.; Cariolle, D.; Garcia, R. R.; Grose, W. L.; Guthrie, P. D.; Ko, M.; Owens, A. J.; Plumb, R. A.; Prather, M. J.

1985-01-01

16

Toilet Model  

NSDL National Science Digital Library

In this activity, PVC pipe, plastic water bottles and vinyl tubing are used to make a simple working toilet model. The model shows the role of a siphon in the flushing of a toilet. Educators can pre-assemble this model and use it for demonstration purposes or engage learners in the model building process.

Rathjen, Don

2005-01-01

17

Understanding Models  

NSDL National Science Digital Library

Chapter 1 defines and discusses models in a broad, and perhaps unusual, way. In particular, the chapter stresses the framework of personal models that underlie science and learning across fields. Subsequent chapters will deal more with particular kinds of expressed models that are important in science and science teaching: physical models, analog models and plans, mathematical models, and computer simulations. Throughout, the book examines how all models are important to science, how they are used, and how to use them effectively. They can and should be used not only to teach science, but also to teach students something about the process of learning and about the nature of knowledge itself.

Ireton, Shirley W.; Gilbert, Steven W.

2003-01-01

18

Model Theory: Infinitary Model Theory  

E-print Network

'. #12;Infinitary Model Theory: Covers of Abelian Varieties John T. Baldwin Hierarchy for L1, 1 completeInfinitary Model Theory: Covers of Abelian Varieties John T. Baldwin Infinitary Model Theory: Covers of Abelian Varieties John T. Baldwin August 16, 2009 #12;Infinitary Model Theory: Covers

Baldwin, John T.

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

ENTRAINMENT MODELS  

EPA Science Inventory

This presentation presented information on entrainment models. Entrainment models use entrainment hypotheses to express the continuity equation. The advantage is that plume boundaries are known. A major disadvantage is that the problems that can be solved are rather simple. The ...

22

Modeling Transformation  

E-print Network

Modeling Transformation What does each step do? #12;Transformation Procedure #12;Transformation Procedure #12;Building Your Model Yarn = chromosomal DNA Beads = ribosomes Black velcro = plasmid DNA Green velcro = GFP gene Pink velcro

Rose, Michael R.

23

Modeling Convection  

NSDL National Science Digital Library

Typically, teachers use simple models that employ differences in temperature and density to help students visualize convection. However, most of these models are incomplete or merely hint at (instead of model) convective circulation. In order to make the use of models more effective, the authors developed an alternative system that uses a simple, low-cost apparatus that not only maintains dynamic convective circulation, but also illustrates two adjacent cells that teaches students about Earth's processes.

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

2004-09-01

24

Model Organisms  

NSDL National Science Digital Library

Each model organism has its own advantages and disadvantages. Choosing an appropriate model depends on the question being asked. Many laboratories find it useful to perform parallel experiments in two or more model systems to understand different aspects of a biochemical process. This animation from Cold Spring Harbor Laboratory's Dolan DNA Learning Center presents Model Organisms through a series of illustrations of the processes involved.

2012-11-19

25

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...

26

Econometric Modelling  

Microsoft Academic Search

The theory of reduction explains the origins of empirical models, by delineating all the steps involved in mapping from the actual data generation process (DGP) in the economy - far too com- plicated and high dimensional ever to be completely modeled - to an empirical model thereof. Each reduction step involves a potential loss of information from: aggregating, marginalizing, condition-

David F. Hendry

27

Graphical Models  

Microsoft Academic Search

Statistical applications in fields such as bioinformatics, information retrieval, speech processing, image processing and communications often involve large-scale models in which thousands or millions of random variables are linked in complex ways. Graphical models provide a general methodology for approaching these problems, and indeed many of the models developed by researchers in these applied fields are instances of the general

Michael I. Jordan

2004-01-01

28

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

29

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

30

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.

31

Rethinking Models  

NSDL National Science Digital Library

While models and analogies are integral to both the learning and practice of science, their use is complex and potentially troublesome. Misconceptions can arise when parts of a model are misleading, missing, or misapplied. Students begin to look critically at models as they investigate a question of personal interest and develop related lessons for use in a local elementary school. This article suggests techniques you can use to analyze models and describes preservice teachers' experiences as they critically examined popular models used in many elementary classrooms.

Frazier, Richard

2003-01-01

32

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

33

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

34

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

35

Kac Model  

NSDL National Science Digital Library

The EJS Kac Model simulates the relaxation of a gas to equilibrium by randomly selecting and then colliding gas molecules but without keeping track of the molecules' positions. As long as the collisions are consistent with spatial isotropy, the Boltzmann speed distribution will emerge. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. The Kac 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_KacModel.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

2009-03-05

36

Phenomenological models  

SciTech Connect

The biological effects of ionizing radiation exposure are the result of a complex sequence of physical, chemical, biochemical, and physiological interactions. One way to begin a search for an understanding of health effects of radiation is through the development of phenomenological models of the response. Many models have been presented and tested in the slowly evolving process of characterizing cellular response. A range of models covering different endpoints and phenomena has developed in parallel. Many of these models employ similar assumptions about some underlying processes while differing about the nature of others. An attempt is made to organize many of the models into groups with similar features and to compare the consequences of those features with the actual experimental observations. It is assumed that by showing that some assumptions are inconsistent with experimental observations, the job of devising and testing mechanistic models can be simplified. 43 refs., 13 figs.

Braby, L.A.

1990-09-01

37

Gimbal Model  

NSDL National Science Digital Library

The Gimbal Model illustrates the pitch, roll and yaw of a 3D object. Independent axis mode allows each axes to be rotated without affecting the others axes. If this mode is not selected, the model can be used to explore the phenomena of gimbal lock. This model tests the Java 3D implementation of the EJS 3D library. If the Java 3D option is selected, a airplane VMRL file (wrl) is rendered inside the gimbals. A warning message will appear if the Java 3D library is not available. The Gimbal 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_ntnu_Gimbal.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.

Hwang, Fu-Kwun; Wee, Loo K.

2011-12-30

38

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

39

Model Cheking  

Microsoft Academic Search

Model checking is an automatic technique for verifying finite-state reactive systems, such as sequential circuit designs and\\u000a communication protocols. Specifications are expressed in temporal logic, and the reactive system is modeled as a statetransition\\u000a graph. An efficient search procedure is used to determine whether or not the state-transition graph satisfies the specifications.\\u000a \\u000a We describe the basic model checking algorithm and

Edmund M. Clarke

1997-01-01

40

PREDICTIVE MODELS  

SciTech Connect

PREDICTIVE MODELS is a collection of five models - CFPM, CO2PM, ICPM, PFPM, and SFPM - used in the 1982-1984 National Petroleum Council study of enhanced oil recovery (EOR) potential. Each pertains to a specific EOR process designed to squeeze additional oil from aging or spent oil fields. The processes are: 1) chemical flooding; 2) carbon dioxide miscible flooding; 3) in-situ combustion; 4) polymer flooding; and 5) steamflood. CFPM, the Chemical Flood Predictive Model, models micellar (surfactant)-polymer floods in reservoirs, which have been previously waterflooded to residual oil saturation. Thus, only true tertiary floods are considered. An option allows a rough estimate of oil recovery by caustic or caustic-polymer processes. CO2PM, the Carbon Dioxide miscible flooding Predictive Model, is applicable to both secondary (mobile oil) and tertiary (residual oil) floods, and to either continuous CO2 injection or water-alternating gas processes. ICPM, the In-situ Combustion Predictive Model, computes the recovery and profitability of an in-situ combustion project from generalized performance predictive algorithms. PFPM, the Polymer Flood Predictive Model, is switch-selectable for either polymer or waterflooding, and an option allows the calculation of the incremental oil recovery and economics of polymer relative to waterflooding. SFPM, the Steamflood Predictive Model, is applicable to the steam drive process, but not to cyclic steam injection (steam soak) processes. The IBM PC/AT version includes a plotting capability to produces a graphic picture of the predictive model results.

Ray, R.M. (DOE Bartlesville Energy Technology Center, Bartlesville, OK (United States))

1988-10-01

41

Turbulence modeling  

NASA Technical Reports Server (NTRS)

The objective of this work is to develop, verify, and incorporate the baseline two-equation turbulence models which account for the effects of compressibility into the three-dimensional Reynolds averaged Navier-Stokes (RANS) code and to provide documented descriptions of the models and their numerical procedures so that they can be implemented into 3-D CFD codes for engineering applications.

Bardina, Jorge E.

1995-01-01

42

GLACPRO Model  

NSDL National Science Digital Library

In the GLACPRO exercise student teams (1-3 members) use a numerical model to reconstruct a former glacial flowline from moraines to source. They must interact with teams studying adjacent flowlines to accurately place ice divides. They can calculate average thicknesses, volumes, ice loading, and sea level equivalent from the class model.

Locke, Bill

43

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.

44

Animal models  

Microsoft Academic Search

Time Series Analysis looks at the properties of time series from a purely statistical point of view. No attempt is made to relate variables using a priori economic theory (c.f. econometrics). Why use time series methods? 1) Short term forecasting. Time series models may well forecast better than econometric models over the short term. One would expect that they would

Hartmut Wekerle; Kimikazu Kojima; Joseli Lannes-Vieira; Hans Lassmann; Christopher Linington

1983-01-01

45

Computational Models  

Cancer.gov

The models work by investigating relationships between the pathways that control a cell's response to inflammation, growth factors, DNA damage, and other events. The goal is to create a dynamic model of the biological processes related to cancer initiation, progression, and metastasis.

46

OSPREY Model  

SciTech Connect

The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes will provide substantial cost savings and many technical benefits. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed within Multi-physics Object Oriented Simulation Environment (MOOSE) developed at the Idaho National Laboratory (INL). Off-gas Separation and REcoverY (OSPREY) models the adsorption of off-gas constituents for dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions. Inputs to the model include gas, sorbent, and column properties, equilibrium and kinetic data, and inlet conditions. The simulation outputs component concentrations along the column length as a function of time from which breakthrough data is obtained. The breakthrough data can be used to determine bed capacity, which in turn can be used to size columns. It also outputs temperature along the column length as a function of time and pressure drop along the column length. Experimental data and parameters were input into the adsorption model to develop models specific for krypton adsorption. The same can be done for iodine, xenon, and tritium. The model will be validated with experimental breakthrough curves. Customers will be given access to OSPREY to used and evaluate the model.

Veronica J. Rutledge

2013-01-01

47

Stereometric Modelling  

NASA Astrophysics Data System (ADS)

These mandatory guidelines are provided for preparation of papers accepted for publication in the series of Volumes of The The stereometric modelling means modelling achieved with : - the use of a pair of virtual cameras, with parallel axes and positioned at a mutual distance average of 1/10 of the distance camera-object (in practice the realization and use of a stereometric camera in the modeling program); - the shot visualization in two distinct windows - the stereoscopic viewing of the shot while modelling. Since the definition of "3D vision" is inaccurately referred to as the simple perspective of an object, it is required to add the word stereo so that "3D stereo vision " shall stand for "three-dimensional view" and ,therefore, measure the width, height and depth of the surveyed image. Thanks to the development of a stereo metric model , either real or virtual, through the "materialization", either real or virtual, of the optical-stereo metric model made visible with a stereoscope. It is feasible a continuous on line updating of the cultural heritage with the help of photogrammetry and stereometric modelling. The catalogue of the Architectonic Photogrammetry Laboratory of Politecnico di Bari is available on line at: http://rappresentazione.stereofot.it:591/StereoFot/FMPro?-db=StereoFot.fp5&-lay=Scheda&-format=cerca.htm&-view

Grimaldi, P.

2012-07-01

48

Modeling Arcs  

NASA Astrophysics Data System (ADS)

Although vacuum arcs were first identified over 110 years ago, they are not yet well understood. We have since developed a model of breakdown and gradient limits that tries to explain, in a self-consistent way: arc triggering, plasma initiation, plasma evolution, surface damage and gradient limits. We use simple PIC codes for modeling plasmas, molecular dynamics for modeling surface breakdown, and surface damage, and mesoscale surface thermodynamics and finite element electrostatic codes for to evaluate surface properties. Since any given experiment seems to have more variables than data points, we have tried to consider a wide variety of arcing (rf structures, e beam welding, laser ablation, etc.) to help constrain the problem, and concentrate on common mechanisms. While the mechanisms can be comparatively simple, modeling can be challenging.

Insepov, Z.; Norem, J.; Vetizer, S.; Mahalingam, S.

2011-12-01

49

Modeling Arcs  

E-print Network

Although vacuum arcs were first identified over 110 years ago, they are not yet well understood. We have since developed a model of breakdown and gradient limits that tries to explain, in a self-consistent way: arc triggering, plasma initiation, plasma evolution, surface damage and gra- dient limits. We use simple PIC codes for modeling plasmas, molecular dynamics for modeling surface breakdown, and surface damage, and mesoscale surface thermodynamics and finite element electrostatic codes for to evaluate surface properties. Since any given experiment seems to have more variables than data points, we have tried to consider a wide variety of arcing (rf structures, e beam welding, laser ablation, etc.) to help constrain the problem, and concentrate on common mechanisms. While the mechanisms can be comparatively simple, modeling can be challenging.

Insepov, Zeke; Veitzer, Seth; Mahalingam, Sudhakar

2011-01-01

50

Modeling Arcs  

SciTech Connect

Although vacuum arcs were first identified over 110 years ago, they are not yet well understood. We have since developed a model of breakdown and gradient limits that tries to explain, in a self-consistent way: arc triggering, plasma initiation, plasma evolution, surface damage and gradient limits. We use simple PIC codes for modeling plasmas, molecular dynamics for modeling surface breakdown, and surface damage, and mesoscale surface thermodynamics and finite element electrostatic codes for to evaluate surface properties. Since any given experiment seems to have more variables than data points, we have tried to consider a wide variety of arcing (rf structures, e beam welding, laser ablation, etc.) to help constrain the problem, and concentrate on common mechanisms. While the mechanisms can be comparatively simple, modeling can be challenging.

Insepov, Z.; Norem, J. [Argonne National Lab, Argonne, IL 60439 (United States); Vetizer, S.; Mahalingam, S. [Tech-X Corp., Boulder, CO (United States)

2011-12-23

51

Theaterspiel Model.  

National Technical Information Service (NTIS)

THEATERSPIEL is a two-sided, closed, computer-assisted, theater-level war game with resolution at division level. The THEATERSPIEL game model consists of the cyclical application of flexible sets of rules, procedures, mathematical expressions, empirical f...

1969-01-01

52

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 geneâÃÂÃÂs name will take you to the National Center for Biological Information, where you can explore the latest relevant scientific literature.

2009-04-14

53

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...

54

PREDICTIVE MODELS  

SciTech Connect

PREDICTIVE MODELS is a collection of five models - CFPM, CO2PM, ICPM, PFPM, and SFPM - used in the 1982-1984 National Petroleum Council study of enhanced oil recovery (EOR) potential. Each pertains to a specific EOR process designed to squeeze additional oil from aging or spent oil fields. The processes are: 1) chemical flooding, where soap-like surfactants are injected into the reservoir to wash out the oil; 2) carbon dioxide miscible flooding, where carbon dioxide mixes with the lighter hydrocarbons making the oil easier to displace; 3) in-situ combustion, which uses the heat from burning some of the underground oil to thin the product; 4) polymer flooding, where thick, cohesive material is pumped into a reservoir to push the oil through the underground rock; and 5) steamflood, where pressurized steam is injected underground to thin the oil. CFPM, the Chemical Flood Predictive Model, models micellar (surfactant)-polymer floods in reservoirs, which have been previously waterflooded to residual oil saturation. Thus, only true tertiary floods are considered. An option allows a rough estimate of oil recovery by caustic or caustic-polymer processes. CO2PM, the Carbon Dioxide miscible flooding Predictive Model, is applicable to both secondary (mobile oil) and tertiary (residual oil) floods, and to either continuous CO2 injection or water-alternating gas processes. ICPM, the In-situ Combustion Predictive Model, computes the recovery and profitability of an in-situ combustion project from generalized performance predictive algorithms. PFPM, the Polymer Flood Predictive Model, is switch-selectable for either polymer or waterflooding, and an option allows the calculation of the incremental oil recovery and economics of polymer relative to waterflooding. SFPM, the Steamflood Predictive Model, is applicable to the steam drive process, but not to cyclic steam injection (steam soak) processes.

Ray, R.M. (DOE Bartlesville Energy Technology Technology Center, Bartlesville, OK (United States))

1986-12-01

55

Everglades Modeling  

NASA Astrophysics Data System (ADS)

The Florida Everglades is a vast, low-relief, nearly horizontal, densely vegetated subtropical wetland with slow-moving water and only trace inputs of sediment and nutrients. The natural system is a classic example of a self-organizing system, with feedbacks between hydrology, vegetation, and soil evolution, but not all controls on landscape patterns are well understood. Engineered features (roads, canals, levees, etc.) have since the 1920s greatly modified the hydrologic regime, resulting in significant loss of peat and degraded patterning. We are developing a nested flow and transport model to try to understand dominant processes in landscape formation. Flow is described in 2D, vertically integrated over the surficial aquifer and surface water (using vegetative-drag models rather than Manning's equation). Transport is described in 3D, with sediment and (in the future) nutrient transport considered. High correlation between vegetative resistance and microtopography allows a parsimonious large-scale [O(1~km)] flow model based on a truncated normal distribution for microtopography that is partitioned by vegetation class. A more complex landscape-unit model describes both flow and transport at the large scale, with the potential of considering landscape evolution. The landscape-unit model considers typical landscape units as additional embedded continua within a slough continuum. The large-scale models can be used on their own, and also to provide boundary conditions for fine-scale [O(10~m)] simulations considering individual landscape features and the local effect of engineered systems.

Stothoff, S. A.; Mitchell-Bruker, S.

2003-12-01

56

Modelling ToolsModelling Tools Steven Fassnacht  

E-print Network

Modelling Tools · Data Analysis ­ Trend identification ­ Projections · Computer Models ­ Process ­ Ensemble Analysis Transpiration Evaporation Precipitation surface runoff groundwater flow Infiltration Model Schematic computer model streamflow precipitation landcover data temperature #12;3 Modelling

57

Modelling Experiments as Mediating Models  

Microsoft Academic Search

Syntactic and structural models specify relationships between their constituents but cannot show what outcomes their interaction\\u000a would produce over time in the world. Simulation consists in iterating the states of a model, so as to produce behaviour over\\u000a a period of simulated time. Iteration enables us to trace the implications and outcomes of inference rules and other assumptions\\u000a implemented in

D. C. Gooding; T. R. Addis

2008-01-01

58

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

59

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

60

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

61

Dynamical approach to heavy-ion induced fission using actinide target nuclei at energies around the Coulomb barrier  

NASA Astrophysics Data System (ADS)

In order to describe heavy-ion fusion reactions around the Coulomb barrier with an actinide target nucleus, we propose a model which combines the coupled-channels approach and a fluctuation-dissipation model for dynamical calculations. This model takes into account couplings to the collective states of the interacting nuclei in the penetration of the Coulomb barrier and the subsequent dynamical evolution of a nuclear shape from the contact configuration. In the fluctuation-dissipation model with a Langevin equation, the effect of nuclear orientation at the initial impact on the prolately deformed target nucleus is considered. Fusion-fission, quasifission, and deep quasifission are separated as different Langevin trajectories on the potential energy surface. Using this model, we analyze the experimental data for the mass distribution of fission fragments (MDFF) in the reactions of 34,36S + 238U and 30Si + 238U at several incident energies around the Coulomb barrier. We find that the time scale in the quasifission as well as the deformation of fission fragments at the scission point are different between the 30Si + 238U and 36S + 238U systems, causing different mass asymmetries of the quasifission.

Aritomo, Y.; Hagino, K.; Nishio, K.; Chiba, S.

2012-04-01

62

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

63

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.

64

Model Behavior  

ERIC Educational Resources Information Center

There are dozens of books and hundreds of resources that address the issue of character development in students: how to raise them to be good people, how to teach them to be good citizens, how to help them to make good decisions. Little is written, however, about the character development of principals and school leaders, whose behavior is a model

Holloway, John

2006-01-01

65

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

66

Model Behavior.  

ERIC Educational Resources Information Center

Statistical modeling provides a method for colleges to use alumni-development information to create an equation predicting who is likely to respond positively to fund-raising appeals. This can make fund raising more cost-effective, provide higher returns on minimal investment, provide results quickly, and improve competitiveness. Resources…

Wylie, Peter B.

1999-01-01

67

Diffusion Models  

NSDL National Science Digital Library

Web-based intructional material describing the use of diffusion models in population ecology. This page is part of a set of on-line lectures on Quantitative Population Ecology produced by Alexei Sharov in the Department of Entomology at Virginia Tech.

Sharov, Alexei

68

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...

69

Micrometer Model  

NSDL National Science Digital Library

This interactive simulation gives students practice in the operation and the physical parts of a real micrometer, a measuring device that employs a screw to amplify distances that are too small to measure easily. The accuracy of a micrometer derives from the accuracy of the thread that is at its heart. The basic operating principle of a micrometer is that the rotation of an accurately made screw can be directly and precisely correlated to a certain amount of axial movement (and vice-versa), through the constant known as the screw's lead. The Micrometer 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_ntnu_Micrometer.jar file to run the program (Java must be installed).

Hwang, Fu-Kwun

2014-06-10

70

Modeling Molecules  

NASA Technical Reports Server (NTRS)

The molecule modeling method known as Multibody Order (N) Dynamics, or MBO(N)D, was developed by Moldyn, Inc. at Goddard Space Flight Center through funding provided by the SBIR program. The software can model the dynamics of molecules through technology which stimulates low-frequency molecular motions and properties, such as movements among a molecule's constituent parts. With MBO(N)D, a molecule is substructured into a set of interconnected rigid and flexible bodies. These bodies replace the computation burden of mapping individual atoms. Moldyn's technology cuts computation time while increasing accuracy. The MBO(N)D technology is available as Insight II 97.0 from Molecular Simulations, Inc. Currently the technology is used to account for forces on spacecraft parts and to perform molecular analyses for pharmaceutical purposes. It permits the solution of molecular dynamics problems on a moderate workstation, as opposed to on a supercomputer.

2000-01-01

71

Simple Models  

NSDL National Science Digital Library

As stated in "About This Book," the author isn't going to take the usual approach to the subject of chemistry. Because virtually all explanations of chemical reactions are based on our current model of atoms and molecules, the first thing to do here is to help you understand why we believe that atoms and molecules look and act the way they do. That's not a trivial issue, because despite the impression you might have gotten from textbooks, no one has ever seen an atom in the sense that you can see this page in front of you. What we have are observations and experiments that lead us to formulate models of atoms. This free selection includes the Table of Contents, Preface, About This Book section, a Safety Note, and the Glossary.

Robertson, William C.

2007-01-01

72

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.

Wattenberg, Frank

1997-01-01

73

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

2009-02-23

74

Model Well  

NSDL National Science Digital Library

In this quick activity about pollutants and groundwater (page 2 of PDF), learners build a model well with a toilet paper tube. Learners use food coloring to simulate pollutants and observe how they can be carried by groundwater and eventually enter water sources such as wells, rivers, and streams. This activity is associated with nanotechnology and relates to linked video, DragonflyTV Nano: Water Clean-up.

Twin Cities Public Television, Inc.

2008-01-01

75

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

76

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

77

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

78

Introduction Model training  

E-print Network

Introduction Model training Experimental results Conclusion Context-Dependent Alignment Models and William Byrne Context-Dependent Alignment Models for SMT #12;Introduction Model training Experimental trees Model training Experimental results Evaluation of alignment quality Translation results Jamie

Byrne, William

79

Modeling uncertainty: quicksand for water temperature modeling  

USGS Publications Warehouse

Uncertainty has been a hot topic relative to science generally, and modeling specifically. Modeling uncertainty comes in various forms: measured data, limited model domain, model parameter estimation, model structure, sensitivity to inputs, modelers themselves, and users of the results. This paper will address important components of uncertainty in modeling water temperatures, and discuss several areas that need attention as the modeling community grapples with how to incorporate uncertainty into modeling without getting stuck in the quicksand that prevents constructive contributions to policy making. The material, and in particular the reference, are meant to supplement the presentation given at this conference.

Bartholow, John M.

2003-01-01

80

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

81

Graphical models, causal inference, and econometric models  

E-print Network

Graphical models, causal inference, and econometric models Peter Spirtes Abstract A graphical model modeling has historical ties to causal modeling in econometrics and other social sciences, there have been isolated from the econometric tradition. In this paper I will describe a number of recent developments

Spirtes, Peter

82

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

83

Technological Forecasting---Model Selection, Model Stability, and Combining Models  

Microsoft Academic Search

The paper identifies 29 models that the literature suggests are appropriate for technological forecasting. These models are divided into three classes according to the timing of the point of inflexion in the innovation or substitution process. Faced with a given data set and such a choice, the issue of model selection needs to be addressed. Evidence used to aid model

Nigel Meade; Towhidul Islam

1998-01-01

84

Software interconnection models  

Microsoft Academic Search

We present a formulation of interconnection models and present the unit and syntactic models — the primary models used for managing the evolution of large software systems. We discuss various tools that use these models and evaluate how well these models support the management of system evolution. We then introduce the semantic interconnection model. The semantic interconnection model incorporates the

Dewayne E. Perry

1987-01-01

85

Pre-saddle neutron multiplicity for fission reactions induced by heavy ions and light particles  

E-print Network

Pre-saddle neutron multiplicity has been calculated for several fission reactions induced by heavy ions and light particles. Experimentally, it is impossible to determine the contribution of neutrons being emitted before the saddle point and those emitted between the saddle and the scission points. Determination of the pre-saddle neutron multiplicity in our research is based on the comparison between the experimental anisotropies and those predicted by the standard saddle-point statistical model. Analysis of the results shows that the pre-saddle neutron multiplicity depends on the fission barrier height and stability of the compound nucleus. In heavy ion induced fission, the number of pre-saddle neutrons decreases with increasing the excitation energy of the compound nucleus. A main cause of this behavior is due to a reduction in the ground state-to-saddle point transition time with increasing the excitation energy of the compound nucleus. Whereas in induced fission by light particles, the number of pre-saddle neutrons increases with increasing the excitation energy of the compound nucleus.

S. Soheyli; M. K. Khalili

2013-06-03

86

Fission barriers and half-lives of actinides in the quasimolecular shape valley  

NASA Astrophysics Data System (ADS)

The energy of actinide nuclei in the fusionlike deformation valley has been determined from a liquid-drop model, taking into account the proximity energy, the mass and charge asymmetries, and the shell and pairing energies. Double-humped potential barriers appear. The saddle point corresponds to the second maximum and to the transition from compact one-body shapes with a deep neck to two touching ellipsoids. The scission point, where the effects of the nuclear attractive forces between the fragments vanish, lies at the end of an energy plateau below the saddle point and corresponds to two well-separated fragments. The kinetic and excitation energies of the fragments come from the energy on this plateau. The shell and pairing effects play a main role to decide the most probable decay path. The heights of the potential barriers roughly agree with the experimental data and the calculated half-lives follow the trend of the experimental values. A shallow third minimum and a third peak appear in specific asymmetric exit channels where one fragment is close to a double magic quasispherical nucleus, while the other one evolves from oblate to prolate shapes.

Royer, G.; Jaffré, M.; Moreau, D.

2012-10-01

87

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

88

Epidemic Modeling: SIRS Models Regina Dolgoarshinnykh  

E-print Network

Epidemic Modeling: SIRS Models Regina Dolgoarshinnykh Columbia University joint with Steven P. Lalley University of Chicago #12;Threshold Phenomena in Epidemic Models · Epidemic models often exhibit the reproductive number is above one, a major epidemic is possible. · The final outcome of the infection spread

Dolgoarshinnykh, Regina

89

Parametric uncertainty modeling for LFT model realization  

Microsoft Academic Search

This paper presents a procedure for parametric uncertainty modeling of a small unmanned aerial vehicle flight dynamics for the purpose of LFT model realization. Experimental data measurements were taken to construct the parametric uncertainties in the 6-DOF nonlinear simulation model for the vehicle . A new approach is used to linearize the uncertain nonlinear simulation model developed and a physically

Yew Chai Paw; Gary J. Balas

2008-01-01

90

Hierarchical Dynamic Models  

E-print Network

Hierarchical Dynamic Models Will Penny OU Processes Embedding OU(2) process Dynamic Models Generalised coordinates Joint Likelihood Filtering Mode Following Dynamic Expectation Maximisation Generative Generative Model Generated Data Filtering Triple Estimation Hierarchical Dynamic Models References

Penny, Will

91

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

92

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

93

Composite Load Model Evaluation  

Microsoft Academic Search

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

Ning Lu; Hong Qiao

2007-01-01

94

Standard Solar Model  

SciTech Connect

Solar models are important in our understanding of stars and stellar evolution. Solar models have been constructed using different methods. In this work, a solar model will be built using the fitting method. The model will incorporate the most recent input data. The model will be evolved to the current epoch starting from the zero-age main sequence model.

Loong, Lim Yaw; Yusof, Norhasliza; Kassim, Hasan Abu [Physics Department, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2008-05-20

95

Modeling cholera outbreaks  

PubMed Central

Mathematical modeling can be a valuable tool for studying infectious disease outbreak dynamics and simulating the effects of possible interventions. Here, we describe approaches to modeling cholera outbreaks and how models have been applied to explore intervention strategies, particularly in Haiti. Mathematical models can play an important role in formulating and evaluating complex cholera outbreak response options. Major challenges to cholera modeling are insufficient data for calibrating models and the need to tailor models for different outbreak scenarios. PMID:23412687

Longini, Ira M.; Morris, J. Glenn

2014-01-01

96

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

97

Model Transformation Reuse with Model Typing  

E-print Network

machines More and more model manipulation operators · Need for a systematic engineering Software Language manipulation 7 8 · Motivating example: model transformation [SoSyM'07] takes as input a state machine Rennes Triskell Research Team http://www.irisa.fr/triskell · A model · Its metamodel · Adding Operational

98

Modeling Biofilms Using Complex Fluid Models  

E-print Network

Modeling Biofilms Using Complex Fluid Models Qi Wang Department of Mathematics Florida State · Phase field models for biofilms · Linear stability analysis of constant steady states · Numerical (optional). · Conclusion #12;Introduction to Biofilms · Biofilms are ubiquitous in nature and manmade

Maryland at College Park, University of

99

Dependence Modelling, Model Risk and Model Calibration in Models of Portfolio Credit Risk  

E-print Network

Dependence Modelling, Model Risk and Model Calibration in Models of Portfolio Credit Risk R@mathematik.uni-leipzig.de Alexander J. McNeil Department of Mathematics Federal Institute of Technology ETH Zentrum CH-8092 Zurich the mathe- matical structure and in particular the modelling of dependence between default events

Frey, Rüdiger

100

The Mobius modeling tool  

Microsoft Academic Search

Despite the development of many modeling formalisms and model solution methods, most tool implementations support only a single formalism. Furthermore, models expressed in the chosen formalism cannot be combined with models expressed in other formalisms. This monolithic approach both limits the usefulness of such tools to practitioners, and hampers modeling research, since it is difficult to compare new and existing

Graham Clark; Tod Courtney; David Daly; Dan Deavours; Salem Derisavi; Jay M. Doyle; William H. Sanders; Patrick Webster

2001-01-01

101

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

102

Modeling the Heart  

NSDL National Science Digital Library

Models of the heart have been developed since 1960, starting with the discovery and modeling of potassium channels. The first models of calcium balance were made in the 1980s and have now reached a high degree of physiological detail. During the 1990s, these cell models were incorporated into anatomically detailed tissue and organ models.

Denis Noble (Oxford University Department of Physiology)

2004-08-01

103

Modeling in Computer Graphics  

NSDL National Science Digital Library

A discussion of different modeling techniques in computer graphics including t polygon mesh, parametric cubic curves and patches, implicit functions such as metaballs, procedural modeling (plants and flowers) and modeling transformations.

2003-02-15

104

Earth System Model.  

National Technical Information Service (NTIS)

The Earth System Model is the natural evolution of current climate models and will be the ultimate embodiment of our geophysical understanding of the planet. These models are constructed from components - atmosphere, ocean, ice, land, chemistry, solid ear...

M. Schoeberl, R. B. Rood, P. Hildebrand, C. Raymond

2003-01-01

105

Models of magnetism  

NSDL National Science Digital Library

This study investigates the mental models that people construct about magnetic phenomena. The project involved students, physics teachers, engineers, and practitioners. The researchers propose five models following a progression from simple description to a field model. Contains 28 references.

Borges, A. T.; Gilbert, John; Tecnico, Colegio

2006-05-23

106

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

107

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 ...

108

Models of Magnetism.  

ERIC Educational Resources Information Center

Investigates the mental models that people construct about magnetic phenomena. Involves students, physics teachers, engineers, and practitioners. Proposes five models following a progression from simple description to a field model. Contains 28 references. (DDR)

Borges, A. Tarciso; Gilbert, John K.

1998-01-01

109

Quantum model averaging  

NASA Astrophysics Data System (ADS)

Standard tomographic analyses ignore model uncertainty. It is assumed that a given model generated the data and the task is to estimate the quantum state, or a subset of parameters within that model. Here we apply a model averaging technique to mitigate the risk of overconfident estimates of model parameters in two examples: (1) selecting the rank of the state in tomography and (2) selecting the model for the fidelity decay curve in randomized benchmarking.

Ferrie, Christopher

2014-09-01

110

Modeling of geothermal systems  

SciTech Connect

During the last decade the use of numerical modeling for geothermal resource evaluation has grown significantly, and new modeling approaches have been developed. In this paper we present a summary of the present status in numerical modeling of geothermal systems, emphasizing recent developments. Different modeling approaches are described and their applicability discussed. The various modeling tasks, including natural-state, exploitation, injection, multi-component and subsidence modeling, are illustrated with geothermal field examples. 99 refs., 14 figs.

Bodvarsson, G.S.; Pruess, K.; Lippmann, M.J.

1985-03-01

111

Validating simulation models  

Microsoft Academic Search

In this paper we give a general introduction to model validation, define the various validation techniques, discuss conceptual and operational validity, and present a recommended model validation procedure.

Robert G. Sargent

1983-01-01

112

BioModels Database  

NSDL National Science Digital Library

Hosted by the European Bioinformatics Institute, the BioModels Database is a collaborative, "new effort to develop a data resource that will allow biologist to store, search and retrieve published mathematical models of biological interests. The models in the BioModels Database are annotated and linked to relevant data resources, such as publications, databases of compounds and pathways, controlled vocabularies, etc." The website allows visitors to browse and search the Database for models. The site also provides information about submitting models for the Database. It should be noted that submitted models must undergo tests conducted by BioModels Database curators before they are incorporated. [NL

113

Continuous system modeling  

NASA Technical Reports Server (NTRS)

A comprehensive and systematic introduction is presented for the concepts associated with 'modeling', involving the transition from a physical system down to an abstract description of that system in the form of a set of differential and/or difference equations, and basing its treatment of modeling on the mathematics of dynamical systems. Attention is given to the principles of passive electrical circuit modeling, planar mechanical systems modeling, hierarchical modular modeling of continuous systems, and bond-graph modeling. Also discussed are modeling in equilibrium thermodynamics, population dynamics, and system dynamics, inductive reasoning, artificial neural networks, and automated model synthesis.

Cellier, Francois E.

1991-01-01

114

PREDICTIVE MODELS. Enhanced Oil Recovery Model  

SciTech Connect

PREDICTIVE MODELS is a collection of five models - CFPM, CO2PM, ICPM, PFPM, and SFPM - used in the 1982-1984 National Petroleum Council study of enhanced oil recovery (EOR) potential. Each pertains to a specific EOR process designed to squeeze additional oil from aging or spent oil fields. The processes are: 1 chemical flooding; 2 carbon dioxide miscible flooding; 3 in-situ combustion; 4 polymer flooding; and 5 steamflood. CFPM, the Chemical Flood Predictive Model, models micellar (surfactant)-polymer floods in reservoirs, which have been previously waterflooded to residual oil saturation. Thus, only true tertiary floods are considered. An option allows a rough estimate of oil recovery by caustic or caustic-polymer processes. CO2PM, the Carbon Dioxide miscible flooding Predictive Model, is applicable to both secondary (mobile oil) and tertiary (residual oil) floods, and to either continuous CO2 injection or water-alternating gas processes. ICPM, the In-situ Combustion Predictive Model, computes the recovery and profitability of an in-situ combustion project from generalized performance predictive algorithms. PFPM, the Polymer Flood Predictive Model, is switch-selectable for either polymer or waterflooding, and an option allows the calculation of the incremental oil recovery and economics of polymer relative to waterflooding. SFPM, the Steamflood Predictive Model, is applicable to the steam drive process, but not to cyclic steam injection (steam soak) processes. The IBM PC/AT version includes a plotting capability to produces a graphic picture of the predictive model results.

Ray, R.M. [DOE Bartlesville Energy Technology Center, Bartlesville, OK (United States)

1992-02-26

115

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

116

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

117

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

118

Qualitative Student Models.  

ERIC Educational Resources Information Center

The concept of a qualitative model is used as the focus of this review of qualitative student models in order to compare alternative computational models and to contrast domain requirements. The report is divided into eight sections: (1) Origins and Goals (adaptive instruction, qualitative models of processes, components of an artificial…

Clancey, William J.

119

Model Theory and Quantum  

E-print Network

Model Theory and Quantum Groups Sonia L'Innocente Model Theory and Quantum Groups Sonia L'Innocente (University of Mons) Model Theory and Quantum Groups 1 / 40 #12;Model Theory and Quantum Groups Sonia L quantum plane, submitted. This work is inspired by Ivo Herzog's paper: The pseudo-finite dimensional

Mons-Hainaut, Université de

120

Interactive Street Modeling  

E-print Network

field T street graph G 9 #12;Tensor Field DesignTensor Field Design - = ab ba yx1 #12;Interactive Procedural Street Modeling Interactive Procedural Street Modeling Guoning Chen1 University 3 Procedural Inc. / ETH Zürich #12;Street ModelingStreet Modeling Images by Eric Hanson and Ben

Chen, Guoning

121

Heat pump modeling  

Microsoft Academic Search

Computer models of the performance of heat pumps and of individual components are described; preliminary results from system improvement studies using these models are presented. Heat exchanger models, based on a tube-by-tube computational approach, may be used by the system model when appropriate. Comparisons of calculated and observed performance parameters for heat exchangers in the laboratory are shown.

R. D. Ellison; F. A. Creswick; C. K. Rice; W. L. Jackson; S. K. Fischer

1979-01-01

122

Mesoscale Ocean Circulation Models  

NSDL National Science Digital Library

This module examines mesoscale ocean circulation models and features and processes that they predict. These models simulate temperature, salinity, currents, and elevation in 3 dimensions through a period of time. They have sufficient resolution to simulate features like fronts, eddies, upwelling, and internal tides. In this module, we examine current operational models, limitations to model forecasts, examples of predicted ocean features, and potential applications.

Comet

2009-05-21

123

Model checking and abstraction  

Microsoft Academic Search

We describe a method for using abstraction to reduce the complexity of temporal logic model checking. The basis of this method is a way of constructing an abstract model of a program without ever examining the corresponding unabstracted model. We show how this abstract model can be used to verify properties of the original program. We have implemented a system

Edmund M. Clarke; Orna Grumberg; David E. Long

1992-01-01

124

Model checking and abstraction  

Microsoft Academic Search

We describe a method for using abstraction to reduce the complexity of temporal-logic model checking. Using techniques similar to those involved in abstract interpretation, we construct an abstract model of a program without ever examining the corresponding unabstracted model. We show how this abstract model can be used to verify properties of the original program. We have implemented a system

Edmund M. Clarke; Orna Grumberg; David E. Long

1994-01-01

125

The POSTGRES Data Model  

Microsoft Academic Search

The design of the POSTGRES data model is described. The data model is a relational model that has been extended with abstract data types including user-defined operators and procedures, relation attributes of type pro- cedure, and attribute and procedure inheri- tance. These mechanism can be used to simu- late a wide variety of semantic and object- oriented data modeling constructs

Lawrence A. Rowe; Michael Stonebraker

1987-01-01

126

Models for computational steering  

Microsoft Academic Search

This paper describes a conceptual model for computational program steering. By exploiting previous results attained in program monitoring, debugging, and configuration, the abstractions and mechanisms derived from this model are shown suitable for both algorithmic and human interactive steering. A characterization of existing systems for computational steering using the model's abstractions demonstrate such generality. The model is illustrated through its

Jeffrey Vetter; Karsten Schwan

1996-01-01

127

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.

Comet

2008-02-05

128

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

129

The Virtual Model Repository  

NASA Astrophysics Data System (ADS)

The Virtual Model Repository is a newly funded VxO (Virtual Observatory) which plans to integrate computational model results with observed data by facilitating visualization, data/model comparisons, and independent interpretation of model results. We will give an overview of the VMR project and its progress as well as examples of its use. Specifically, we will demonstrate searching for and selecting a CCMC computation model. Then, using other VxO APIs, we will pull in relevant observed satellite data for the modeled time period and location. Finally, we will provide visualization of the relative locations of the data with some data/model comparisons.

de Zeeuw, D.; Ridley, A.; Bashkirov, V.; Maddox, M.

2008-12-01

130

Stable models of superacceleration  

SciTech Connect

We discuss an instability in a large class of models where dark energy is coupled to matter. In these models the mass of the scalar field is much larger than the expansion rate of the Universe. We find models in which this instability is absent, and show that these models generically predict an apparent equation of state for dark energy smaller than -1, i.e., superacceleration. These models have no acausal behavior or ghosts.

Kaplinghat, Manoj; Rajaraman, Arvind [Department of Physics and Astronomy University of California, Irvine, California 92697 (United States)

2007-05-15

131

Models in algebraic statistics Toric models  

E-print Network

Varieties in Algebraic Statistics Math in the Mountains Tutorial John B. Little Department of Mathematics and Computer Science College of the Holy Cross July 29-31, 2013 John B. Little Toric Varieties in Algebraic B. Little Toric Varieties in Algebraic Statistics #12;Models in algebraic statistics Toric models

Little, John B.

132

Modeling Multilevel Survival Data Using Frailty Models  

Microsoft Academic Search

Often the dependence in multivariate survival data is modeled through an individual level effect called the frailty. Due to its mathematical simplicity, the gamma distribution is often used as the frailty distribution for hazard modeling. However, it is well known that the gamma frailty distribution has many drawbacks. For example, it weakens the effect of covariates. In addition, in the

Sungduk Kim; Dipak K. Dey

2008-01-01

133

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

134

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

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

Modelling Individual Globular Clusters  

NASA Astrophysics Data System (ADS)

Astronomers have constructed models of globular clusters for over 100 years. These models mainly fall into two categories: (i) static models, such as King's model and its variants, and (ii) evolutionary models. Most attention has been given to static models, which are used to estimate mass-to-light ratios and mass segregation, and to combine data from proper motions and radial velocities. Evolutionary models have been developed for a few objects using the gaseous model, the Fokker-Planck model, Monte Carlo models and N-body models. These models have had a significant role in the search for massive black holes in globular clusters, for example. In this presentation the problems associated with these various techniques will be summarised, and then we shall describe new work with Giersz's Monte Carlo code, which has been enhanced recently to include the stellar evolution of single and binary stars. We describe in particular recent attempts to model the nearby globular cluster M4, including predictions on the spatial distribution of binary stars and their semi-major axis distribution, to illustrate the effects of about 12 Gyr of dynamical evolution. We also discuss work on an approximate way of predicting the “initial” conditions for such modelling.

Heggie, Douglas C.; Giersz, Mirek

2008-05-01

137

Stochastic modeling of rainfall  

SciTech Connect

We review several approaches in the literature for stochastic modeling of rainfall, and discuss some of their advantages and disadvantages. While stochastic precipitation models have been around at least since the 1850`s, the last two decades have seen an increased development of models based (more or less) on the physical processes involved in precipitation. There are interesting questions of scale and measurement that pertain to these modeling efforts. Recent modeling efforts aim at including meteorological variables, and may be useful for regional down-scaling of general circulation models.

Guttorp, P. [Univ. of Washington, Seattle, WA (United States)

1996-12-31

138

Reduced Vector Preisach Model  

NASA Technical Reports Server (NTRS)

A new vector Preisach model, called the Reduced Vector Preisach model (RVPM), was developed for fast computations. This model, derived from the Simplified Vector Preisach model (SVPM), has individual components that like the SVPM are calculated independently using coupled selection rules for the state vector computation. However, the RVPM does not require the rotational correction. Therefore, it provides a practical alternative for computing the magnetic susceptibility using a differential approach. A vector version, using the framework of the DOK model, is implemented. Simulation results for the reduced vector Preisach model are also presented.

Patel, Umesh D.; Torre, Edward Della; Day, John H. (Technical Monitor)

2002-01-01

139

Climate model postprocessing  

NASA Technical Reports Server (NTRS)

The development of new postprocessing software of the climate modeling group is summarized. Code, test, and perform simulations with global general circulation models are described. The models improve understanding and ability to predict the vagaries of weather and climate. To learn from and utilize the model results, it is necessary to create elaborate postprocessing software to allow analysis of the large volume of data produced. The models produce sigma history tapes. The sigma history records are interpolated to pressure history records, which are written on a pressure history tape. The model results are analyzed on pressure surfaces, with snap shots or time averages.

Abeles, J.; Pittarelli, E.; Randall, D. A.

1981-01-01

140

Nitrogen Crop Response Model  

NSDL National Science Digital Library

This on-line dynamic model from Horticulture Research International (HRI) "simulates the growth response of 25 crops to applications of nitrogen fertilizer." The model incorporates the effects of climate, organic material and leaching. Users select a region of the world, enter input into the model (e.g., crop type, date of sowing, weather conditions, nitrogen applications, etc.), and run the model for numeric and graphical output. Substantial effort has been made to describe the model's behavior and to present useful output; interested users may select the "advanced" or "detailed" options for further information on each model.

Aycott, Ann.; Greenwood, Duncan J.; Rahn, Clive R.

141

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.

142

Gear mesh compliance modeling  

NASA Technical Reports Server (NTRS)

A computer model has been constructed to simulate the compliance and load sharing in a spur gear mesh. The model adds the effect of rim deflections to previously developed state-of-the-art gear tooth deflection models. The effects of deflections on mesh compliance and load sharing are examined. The model can treat gear meshes composed to two external gears or an external gear driving an internal gear. The model includes deflection contributions from the bending and shear in the teeth, the Hertzian contact deformations, and primary and secondary rotations of the gear rims. The model shows that rimmed gears increase mesh compliance and, in some cases, improve load sharing.

Savage, M.; Caldwell, R. J.; Wisor, G. D.; Lewicki, D. G.

1986-01-01

143

Modeling worldwide highway networks  

NASA Astrophysics Data System (ADS)

This Letter addresses the problem of modeling the highway systems of different countries by using complex networks formalism. More specifically, we compare two traditional geographical models with a modified geometrical network model where paths, rather than edges, are incorporated at each step between the origin and the destination vertices. Optimal configurations of parameters are obtained for each model and used for the comparison. The highway networks of Australia, Brazil, India, and Romania are considered and shown to be properly modeled by the modified geographical model.

Villas Boas, Paulino R.; Rodrigues, Francisco A.; da F. Costa, Luciano

2009-12-01

144

Marine Wave Model Matrix  

NSDL National Science Digital Library

The Marine Wave Model Matrix provides information on the formulation of wave models developed by the National Centers for Environmental Prediction (NCEP) and other modeling centers, including how these models forecast the generation, propagation, and dissipation of ocean waves using NWP model forecasts for winds and near-surface temperature and stability. Additionally, information is provided on data assimilation, post-processing of data, and verfication of wave models currently in operation. Within the post-processing pages are links to forecast output both in graphical and raw form, including links for data downloads. Links to COMET training on wave processes are also provided.

Comet

2006-05-16

145

Modeling error in Approximate Deconvolution Models  

E-print Network

We investigate the assymptotic behaviour of the modeling error in approximate deconvolution model in the 3D periodic case, when the order $N$ of deconvolution goes to $\\infty$. We consider successively the generalised Helmholz filters of order $p$ and the Gaussian filter. For Helmholz filters, we estimate the rate of convergence to zero thanks to energy budgets, Gronwall's Lemma and sharp inequalities about Fouriers coefficients of the residual stress. We next show why the same analysis does not allow to conclude convergence to zero of the error modeling in the case of Gaussian filter, leaving open issues.

Adrian Dunca; Roger Lewandowski

2011-11-28

146

Modeling Guru: Knowledge Base for NASA Modelers  

NASA Astrophysics Data System (ADS)

Modeling Guru is an on-line knowledge-sharing resource for anyone involved with or interested in NASA's scientific models or High End Computing (HEC) systems. Developed and maintained by the NASA's Software Integration and Visualization Office (SIVO) and the NASA Center for Computational Sciences (NCCS), Modeling Guru's combined forums and knowledge base for research and collaboration is becoming a repository for the accumulated expertise of NASA's scientific modeling and HEC communities. All NASA modelers and associates are encouraged to participate and provide knowledge about the models and systems so that other users may benefit from their experience. Modeling Guru is divided into a hierarchy of communities, each with its own set forums and knowledge base documents. Current modeling communities include those for space science, land and atmospheric dynamics, atmospheric chemistry, and oceanography. In addition, there are communities focused on NCCS systems, HEC tools and libraries, and programming and scripting languages. Anyone may view most of the content on Modeling Guru (available at http://modelingguru.nasa.gov/), but you must log in to post messages and subscribe to community postings. The site offers a full range of "Web 2.0" features, including discussion forums, "wiki" document generation, document uploading, RSS feeds, search tools, blogs, email notification, and "breadcrumb" links. A discussion (a.k.a. forum "thread") is used to post comments, solicit feedback, or ask questions. If marked as a question, SIVO will monitor the thread, and normally respond within a day. Discussions can include embedded images, tables, and formatting through the use of the Rich Text Editor. Also, the user can add "Tags" to their thread to facilitate later searches. The "knowledge base" is comprised of documents that are used to capture and share expertise with others. The default "wiki" document lets users edit within the browser so others can easily collaborate on the same document, even allowing the author to select those who may edit and approve the document. To maintain knowledge integrity, all documents are moderated before they are visible to the public. Modeling Guru, running on Clearspace by Jive Software, has been an active resource to the NASA modeling and HEC communities for more than a year and currently has more than 100 active users. SIVO will soon install live instant messaging support, as well as a user-customizable homepage with social-networking features. In addition, SIVO plans to implement a large dataset/file storage capability so that users can quickly and easily exchange datasets and files with one another. Continued active community participation combined with periodic software updates and improved features will ensure that Modeling Guru remains a vibrant, effective, easy-to-use tool for the NASA scientific community.

Seablom, M. S.; Wojcik, G. S.; van Aartsen, B. H.

2009-05-01

147

A future of the model organism model  

PubMed Central

Changes in technology are fundamentally reframing our concept of what constitutes a model organism. Nevertheless, research advances in the more traditional model organisms have enabled fresh and exciting opportunities for young scientists to establish new careers and offer the hope of comprehensive understanding of fundamental processes in life. New advances in translational research can be expected to heighten the importance of basic research in model organisms and expand opportunities. However, researchers must take special care and implement new resources to enable the newest members of the community to engage fully with the remarkable legacy of information in these fields. PMID:24577733

Rine, Jasper

2014-01-01

148

Biosphere Model Report  

SciTech Connect

The purpose of this report is to document the biosphere model, the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), which describes radionuclide transport processes in the biosphere and associated human exposure that may arise as the result of radionuclide release from the geologic repository at Yucca Mountain. The biosphere model is one of the process models that support the Yucca Mountain Project (YMP) Total System Performance Assessment (TSPA) for the license application (LA), TSPA-LA. The ERMYN provides the capability of performing human radiation dose assessments. This report documents the biosphere model, which includes: (1) Describing the reference biosphere, human receptor, exposure scenarios, and primary radionuclides for each exposure scenario (Section 6.1); (2) Developing a biosphere conceptual model using site-specific features, events, and processes (FEPs) (Section 6.2), the reference biosphere (Section 6.1.1), the human receptor (Section 6.1.2), and approximations (Sections 6.3.1.4 and 6.3.2.4); (3) Building a mathematical model using the biosphere conceptual model (Section 6.3) and published biosphere models (Sections 6.4 and 6.5); (4) Summarizing input parameters for the mathematical model, including the uncertainty associated with input values (Section 6.6); (5) Identifying improvements in the ERMYN compared with the model used in previous biosphere modeling (Section 6.7); (6) Constructing an ERMYN implementation tool (model) based on the biosphere mathematical model using GoldSim stochastic simulation software (Sections 6.8 and 6.9); (7) Verifying the ERMYN by comparing output from the software with hand calculations to ensure that the GoldSim implementation is correct (Section 6.10); (8) Validating the ERMYN by corroborating it with published biosphere models; comparing conceptual models, mathematical models, and numerical results (Section 7).

D.W. Wu; A.J. Smith

2004-11-08

149

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

150

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

151

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 ...

152

Subjects, Models, Languages, Transformations  

Microsoft Academic Search

Discussions about model-driven approaches tend to be ham- pered by terminological confusion. This is at least partially caused by a lack of formal precision in dening the basic concepts, including that of \\\\model\\

Arend Rensink

2004-01-01

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

Performance Models Implementation  

E-print Network

Background Algorithms Performance Models Implementation Summary Avoiding Communication in Sp of computation Communication avoiding: Trade o communication with computation. Arbitrary speedups possible Mohiyuddin et al. Avoiding Comm. in SpMV-like Comp. 1/ 25 #12;Background Algorithms Performance Models

California at Berkeley, University of

155

Nonparametric Bayesian behavior modeling  

E-print Network

As autonomous robots are increasingly used in complex, dynamic environments, it is crucial that the dynamic elements are modeled accurately. However, it is often difficult to generate good models due to either a lack of ...

Joseph, Joshua Mason

2008-01-01

156

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.

Joiner, David; The Shodor Education Foundation, Inc.

157

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

158

Dahl friction modeling  

E-print Network

The drive behind improved friction models has been better prediction and control of dynamic systems. The earliest model was of classical Coulomb friction; however, the discontinuity during force reversal of the Coulomb ...

Chou, Danielle, 1981-

2004-01-01

159

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

160

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

161

Bounding species distribution models  

USGS Publications Warehouse

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. ?? 2011 Current Zoology.

Stohlgren, T.J.; Jarnevich, C.S.; Esaias, W.E.; Morisette, J.T.

2011-01-01

162

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 ...

163

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

164

Mass modeling for bars  

NASA Technical Reports Server (NTRS)

Methods of modeling mass for bars are surveyed. A method for extending John Archer's concept of consistent mass beyond just translational inertia effects is included. Recommendations are given for various types of modeling situations.

Butler, Thomas G.

1987-01-01

165

The Cap Pele Model.  

ERIC Educational Resources Information Center

Reports on a model of environmental education that aims to encourage greater attachment to the bioregion of Arcadia. The model results from cooperation within a village community and addresses the environmental education of people of all ages. (DDR)

Pruneau, Diane; Chouinard, Omer; Arsenault, Charline

1998-01-01

166

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

167

Behavior Modeling for Results.  

ERIC Educational Resources Information Center

Discusses the benefits of behavior modeling, examines the Behavior Modeling Learning Staircase (which illustrates the situational and generic skills that can be developed in a supervisory training program), and describes the role of the trainer. (CT)

Hultman, Kenneth E.

1986-01-01

168

Model documention: Commercial Sector Energy Model. [CSEM  

SciTech Connect

The CSEM forecasts floorspace area and demand for natural gas, electricity and fuel oil for six building categories in four Census regions. Real disposable personal income, population and real fuel prices are the major exogenous drivers of these forecasts. The commercial model uses the coefficients from the three econometric submodules to calculate building floorspace, end-use fuel choices, and utilization (enegy use per square foot) for the three major fuels. Separately from these structural components the model also calculates energy use for the minor fuels liquefied petroleum gas, kerosene, coal and motor gasoline. Through the use of accounting equations, the commercial model combines the structural components to get total commercial energy use over the major fuels. It then adds in the minor fuels, passes the information back to the other models and writes reports.

Not Available

1984-08-10

169

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

170

Modelling pelagic biogeography  

NASA Astrophysics Data System (ADS)

Various combinations of physical and biological models are used to explore factors that determine the distribution of organisms in the world's oceans. The physical models examined include simple box models with parameterized inter-box exchanges that take into account variable box geometries, and specified continuous flows either in the Eulerian frame as stream-functions or as Lagrangian trajectories. A 1-dimensional mixed-layer model and a primitive equation channel model are introduced as examples of dynamical models depicting ocean physics. Biological models are discussed starting with a simple nitrogen (N), phytoplankton (P), zooplankton (Z) and detritus (D), NPZD formulation. The equilibria of this model is explored analytically as an example of computing steady state solutions, and then considering where in parameter space extinction occurs. Nonlinearities and expansion of NPZD to multi-species models are also treated. This is followed by the introduction of a nonlinear three-component food chain model, multi-species Lotka-Voltera competition models, and finally a discussion of structured population models including a derivation of a genetics model written in terms of genotypes. The physical models are then coupled with the biological ones in a series of examples. Both the box model with Lotka-Voltera multi-species population dynamics, and the 1-dimensional mixed-layer model with NPZD are used to demonstrate how the existence of spatial and temporal niches can allow a large number of species to coexist within biogeographic domains even though conditions at most sites and times are not conducive to supporting such diversity. These models recreate the basic diversity patterns observed in the pelagic ecosystem at various latitudes. The box model simulations also demonstrate the tendency for diffusive models to overestimate the dispersion of a species. In order to explore the dynamics of the edges of biogeographic domains a three species food chain model is combined with a Lagrangian trajectory calculation that specifies the dynamics of populations in a meandering jet environment. This model shows that the interaction of biological and physical dynamics can produce complex species distribution patterns that would be difficult to interpret from field observations of species abundance alone. Finally, results from a population genetics box model show that even when there is significant exchange of organisms between domains and natural selection affects allele and genotype proportions, genotype frequencies are in approximate Hardy-Weinberg equilibrium. This demonstrates the overly restrictive nature of some of the Hardy-Weinberg assumptions and provides a means for exploring population dynamics in a biogeographic context.

Olson, Donald B.; Hood, Raleigh R.

171

PREDICTIVE MODELS. Enhanced Oil Recovery Model  

SciTech Connect

PREDICTIVE MODELS is a collection of five models - CFPM, CO2PM, ICPM, PFPM, and SFPM - used in the 1982-1984 National Petroleum Council study of enhanced oil recovery (EOR) potential. Each pertains to a specific EOR process designed to squeeze additional oil from aging or spent oil fields. The processes are: 1 chemical flooding, where soap-like surfactants are injected into the reservoir to wash out the oil; 2 carbon dioxide miscible flooding, where carbon dioxide mixes with the lighter hydrocarbons making the oil easier to displace; 3 in-situ combustion, which uses the heat from burning some of the underground oil to thin the product; 4 polymer flooding, where thick, cohesive material is pumped into a reservoir to push the oil through the underground rock; and 5 steamflood, where pressurized steam is injected underground to thin the oil. CFPM, the Chemical Flood Predictive Model, models micellar (surfactant)-polymer floods in reservoirs, which have been previously waterflooded to residual oil saturation. Thus, only true tertiary floods are considered. An option allows a rough estimate of oil recovery by caustic or caustic-polymer processes. CO2PM, the Carbon Dioxide miscible flooding Predictive Model, is applicable to both secondary (mobile oil) and tertiary (residual oil) floods, and to either continuous CO2 injection or water-alternating gas processes. ICPM, the In-situ Combustion Predictive Model, computes the recovery and profitability of an in-situ combustion project from generalized performance predictive algorithms. PFPM, the Polymer Flood Predictive Model, is switch-selectable for either polymer or waterflooding, and an option allows the calculation of the incremental oil recovery and economics of polymer relative to waterflooding. SFPM, the Steamflood Predictive Model, is applicable to the steam drive process, but not to cyclic steam injection (steam soak) processes.

Ray, R.M. [DOE Bartlesville Energy Technology Technology Center, Bartlesville, OK (United States)

1992-02-26

172

Solid Waste Projection Model: Model user's guide  

SciTech Connect

The Solid Waste Projection Model (SWPM) system is an analytical tool developed by Pacific Northwest Laboratory (PNL) for Westinghouse Hanford company (WHC) specifically to address solid waste management issues at the Hanford Central Waste Complex (HCWC). This document, one of six documents supporting the SWPM system, contains a description of the system and instructions for preparing to use SWPM and operating Version 1 of the model. 4 figs., 1 tab.

Stiles, D.L.; Crow, V.L.

1990-08-01

173

Modelling software components  

Microsoft Academic Search

Argues that precise visual modelling techniques are important for modelling large-scale software components, as they facilitate the core activities of component-based software development (CBSD): building, finding, adapting and assembling components. This paper argues for a carefully selected set of techniques based on the Unified Modelling Language (UML), to provide accessible yet precise component models. The authors then sketch a high-level

Stuart Kent; John Howse; Anthony Lauder

1998-01-01

174

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

175

Mathematical circulatory system model  

NASA Technical Reports Server (NTRS)

A system and method of modeling a circulatory system including a regulatory mechanism parameter. In one embodiment, a regulatory mechanism parameter in a lumped parameter model is represented as a logistic function. In another embodiment, the circulatory system model includes a compliant vessel, the model having a parameter representing a change in pressure due to contraction of smooth muscles of a wall of the vessel.

Lakin, William D. (Inventor); Stevens, Scott A. (Inventor)

2010-01-01

176

The LISA integrated model  

NASA Astrophysics Data System (ADS)

LISA has unique needs that argue for an aggressive modelling effort. These models ultimately need to forecast and interrelate the behaviour 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 paper presents an overview of the LISA integrated modelling effort.

Merkowitz, Stephen M.

2003-05-01

177

Paleoclimate Model Output Visualization  

NSDL National Science Digital Library

This site from the National Climatic Data Center features a tool that displays map images for paleoclimate simulations from various agencies, including COHMAP (CCMO and CCM1), the NASA Goddard Institute for Space Studies (GISS Model II and II') and NCAR. There is also a link to a page containing visualization tools for models from the Paleoclimate Modelling Intercomparison Project(PMIP) database. Each model is extensively documented, and a database is also included.

Center, National C.; Noaa

178

Wonderland climate model  

NASA Astrophysics Data System (ADS)

We obtain a highly efficient global climate model by defining a sector version (120° of longitude) of the coarse resolution Goddard Institute for Space Studies model II. The geography of Wonderland is chosen such that the amount of land as a function of latitude is the same as on Earth. We show that the zonal mean climate of the Wonderland model is very similar to that of the parent model II.

Hansen, J.; Ruedy, R.; Lacis, A.; Russell, G.; Sato, M.; Lerner, J.; Rind, D.; Stone, P.

1997-03-01

179

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

180

Hierarchical Bass model  

NASA Astrophysics Data System (ADS)

We propose a new model about diffusion of a product which includes a memory of how many adopters or advertisements a non-adopter met, where (non-)adopters mean people (not) possessing the product. This effect is lacking in the Bass model. As an application, we utilize the model to fit the iPod sales data, and so the better agreement is obtained than the Bass model.

Tashiro, Tohru

2014-03-01

181

Modeling of spacecraft charging  

NASA Technical Reports Server (NTRS)

Three types of modeling of spacecraft charging are discussed: statistical models, parametric models, and physical models. Local time dependence of circuit upset for DoD and communication satellites, and electron current to a sphere with an assumed Debye potential distribution are presented. Four regions were involved in spacecraft charging: (1) undisturbed plasma, (2) plasma sheath region, (3) spacecraft surface, and (4) spacecraft equivalent circuit.

Whipple, E. C., Jr.

1977-01-01

182

Model driven edge detection  

Microsoft Academic Search

Standard edge detectors fail to find most relevant edges, finding either too many or too few, because they lack a geometric model to guide their search. We present a technique that integrates both photometric and geometric models with an initial estimate of the boundary. The strength of this approach lies in the ability of the geometric model to overcome various

Pascal Fua; Yvan G. Leclerc

1989-01-01

183

Simplicial Chiral Models  

E-print Network

Principal chiral models on a d-1 dimensional simplex are introduced and studied analytically in the large $N$ limit. The $d = 0, 2, 4$ and $\\infty$ models are explicitly solved. Relationship with standard lattice models and with few-matrix systems in the double scaling limit are discussed.

Paolo Rossi; Chung-I Tan

1994-12-20

184

Nuclear Shell Models  

Microsoft Academic Search

The principal features of the several shell models now under discussions are described briefly. The magnetic moments of odd nuclei have been interpreted as (a) supporting an extreme single particle model (Schmidt limits) and (b) as generally consistent with a uniform model (Margenau-Wigner limits). The evidence is consistent with a composite interpretation based on (a) the approximate validity of the

Eugene Feenberg

1950-01-01

185

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

186

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

187

The Single Model Principle  

Microsoft Academic Search

Modelling languages such as UML are increasingly used to describe software systems at different levels of abstraction. There are two very different ways of using such languages. One approach is based on the manifestation of a single model, with construction of different views from this model, and with automatic or semi-automatic consistency checking among these views. This follows what we

Richard F. Paige; Jonathan S. Ostroff

2001-01-01

188

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

189

Reasoning and Formal Modelling  

E-print Network

fingerprints on the gun." p q r #12;Reasoning and Formal Modelling for Forensic Science Lecture 4 Prof. DrReasoning 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

Löwe, Benedikt

190

A School Accountability Model.  

ERIC Educational Resources Information Center

This paper describes the development and validation of a school-accountability model. The model is based on the assumption that schools represent dynamic systems in which a change in one element will affect all other elements. The model's primary elements are educational input, processes, and outcomes. The paper examines various accountability…

McLean, James E.; Snyder, Scott W.; Lawrence, Frank R.

191

Fraction Model III  

NSDL National Science Digital Library

This tool allows the individual or the classroom to explore several representations of fractions. After selecting numerator and denominator, any number from 1 to 100, learners see the fraction itself, a visual model, as well as decimal and percent equivalents. They can choose the model to be a circle, a rectangle, or a set model.

Illuminations, Nctm

2000-01-01

192

Two Cognitive Modeling Frontiers  

NASA Astrophysics Data System (ADS)

This paper reviews three hybrid cognitive architectures (Soar, ACT-R, and CoJACK) and how they can support including models of emotions. There remain problems creating models in these architectures, which is a research and engineering problem. Thus, the term cognitive science engineering is introduced as an area that would support making models easier to create, understand, and re-use.

Ritter, Frank E.

193

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

194

EXPOSURE MODELING - SHEDS  

EPA Science Inventory

This presentation provides a general overview of SHEDS model features, describes algorithms in the SHEDS-Air Toxics model that focus on mobile source exposures and multipathway exposures, and presents examples of results from application of the SHEDS-Air Toxics model to benzene i...

195

Modelling a Suspension Bridge.  

ERIC Educational Resources Information Center

The quadratic function can be modeled in real life by a suspension bridge that supports a uniform weight. This activity uses concrete models and computer generated graphs to discover the mathematical model of the shape of the main cable of a suspension bridge. (MDH)

Rawlins, Phil

1991-01-01

196

Vestibular postural control model  

Microsoft Academic Search

Current models for physiological components and a posture control experiment conducted with three normal subjects form the basis for a model which seeks to describe quantitatively the control of body sway when only vestibular motion cues are used. Emphasis is placed on delineating the relative functional roles of the linear and the angular acceleration sensors and on modeling the functional

Lewis M. Nashner

1972-01-01

197

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

198

Textile composites: modelling strategies  

Microsoft Academic Search

Textile materials are characterised by the distinct hierarchy of structure, which should be represented by a model of textile geometry and mechanical behaviour. In spite of a profound investigation of textile materials and a number of theoretical models existing in the textile literature for different structures, a model covering all structures typical for composite reinforcements is not available. Hence the

S. V. Lomov; G. Huysmans; Y. Luo; R. S. Parnas; A. Prodromou; I. Verpoest; F. R. Phelan

2001-01-01

199

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...

200

Empirical Bayes Linear Models  

E-print Network

Empirical Bayes Will Penny Linear Models fMRI analysis Gradient Ascent Online learning Delta Rule 2011 #12;Empirical Bayes Will Penny Linear Models fMRI analysis Gradient Ascent Online learning Delta) #12;Empirical Bayes Will Penny Linear Models fMRI analysis Gradient Ascent Online learning Delta Rule

Penny, Will

201

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

202

Active Appearance Models  

Microsoft Academic Search

We describe a new method of matching statistical models of appearance to images. A set of model parameters control modes of shape and gray-level variation learned from a training set. We construct an efficient iterative matching algorithm by learning the relationship between perturbations in the model parameters and the induced image errors.

Timothy F. Cootes; Gareth J. Edwards; Christopher J. Taylor

1998-01-01

203

Modeling the Dialectic  

E-print Network

Three formal first-order finite dialectical schemes are investigated. It is shown that schemes 1 and 2 have significantly different finite models. Further, an infinite natural number model for schemes 1, 2, 3 is constructed, and it is shown that scheme 3 has no finite model.

Robert A. Herrmann

2008-10-05

204

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

205

PRESENTATION ON MODELLING AND  

E-print Network

algorithms like FAN and others help in generating less test vectors and test more faults thus saving time and money. #12;CIRCUIT MODELLING · A lot of research has gone into formulation of CMOS device models of the modeling work usually result in full matrices · This enables us to solve real world 3D packaging problems

Patel, Chintan

206

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...

207

Biophysical and spectral modeling  

NASA Technical Reports Server (NTRS)

Activities and results of a project to develop strategies for modeling vegetative canopy reflectance are reported. Specific tasks included the inversion of canopy reflectance models to estimate agronomic variables (particularly leaf area index) from in-situ reflectance measurements, and a study of possible uses of ecological models in analyzing temporal profiles of greenness.

Goel, N. S. (principal investigator)

1982-01-01

208

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

209

Generalized Latent Trait Models.  

ERIC Educational Resources Information Center

Discusses a general model framework within which manifest variables with different distributions in the exponential family can be analyzed with a latent trait model. Presents a unified maximum likelihood method for estimating the parameters of the generalized latent trait model and discusses the scoring of individuals on the latent dimensions.…

Moustaki, Irini; Knott, Martin

2000-01-01

210

Modeling Growth LSystems &Mathematica  

E-print Network

Modeling Growth with L­Systems &Mathematica The symbolic and graphic capabilities of Mathematica map P:S­>S* with ModelingGrowth­MathInEd.ma 1 Mathematica in Education and Research, Volume 4, No. 3 will be produced. ModelingGrowth­MathInEd.ma 2 Mathematica in Education and Research, Volume 4, No. 3 (1995) #12

Jacob, Christian

211

Java Model Checking  

Microsoft Academic Search

This paper presents initial results in model checking multi-threaded Java programs. Java programs are translated into the SAL (Symbolic Analysis Labo- ratory) intermediate language, which supports dy- namic constructs such as object instantiations and thread call stacks. The SAL model checker then ex- haustively checks the program description for dead- locks and assertion failures. Basic model check- ing optimizations that

David Y. W. Park; Jens U. Skakkebaek

2000-01-01

212

Models of Military Expenditure  

Microsoft Academic Search

A brief review of the extensive empirical literature devoted to explaining levels of military expenditure indicates a wide variety of unreconciled results. However, comparing the alternative models is not straightforward. This paper uses British post-war military expenditures to illustrate some of the methodological issues involved in model comparison, evaluation and selection. Starting from two published models for the U.K., a

R. P. Smith

1989-01-01

213

A suicide epidemic model  

Microsoft Academic Search

An epidemic model of suicides clustered in time and space is presented. In this model suicides are depicted as an infection that can be spread from person to person. The model is based on the assumption that spread of suicide ideation via various means of communication increases as the number of suicides increases. A threshold condition for an epidemic to

Barry R. Davis; Robert J. Hardy

1986-01-01

214

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.

Chudler, Eric

2009-01-01

215

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...

216

Modeling Wine Fermentation  

NSDL National Science Digital Library

Humans have been producing wines for thousands of years. How did wine making get started? How has it changed? The Wine Mini-Model simulation enables us to explore the basic fermentation process as well as model enhancements such as the higher alcohol tolerance of cultivated yeasts used in modern wine making. * model the fermentation process in early and modern wines

Ethel D. Stanley (Beloit College;Biology); Howard T. Odum (Beloit College;Biology); Elisabeth C. Odum (Beloit College;Biology); Virginia G. Vaughan (Beloit College;Biology)

2006-05-20

217

Propositional Reasoning by Model  

Microsoft Academic Search

This article describes a new theory of propositional reasoning, that is, deductions depending on if, or, and, and not. The theory proposes that reasoning is a semantic process based on mental models. It assumes that people are able to maintain models of only a limited number of alternative states of affairs, and they accordingly use models representing as much information

P. N. Johnson-Laird; Ruth M. J. Byrne; Walter Schaeken

1992-01-01

218

Models of Earth  

NSDL National Science Digital Library

In this activity, candy models are used to demonstrate the features of the Earth, including its internal structure and layers. Students learn why models are essential in Earth science and answer questions about how their candy models do and do not compare with the actual Earth.

Ladue, Nicole

219

Continuous Growth Models  

NSDL National Science Digital Library

This worksheet compares user-input growth data with predictions under linear, exponential, and logistic models of growth. Students can input parameters for each model; the program graphs the results and computes a crude goodness-of-fit measure. Introduces concepts of modeling and statistical analysis that can be more thoroughly explored using standard statistics software (JMP, SAS, etc.)

Tony Weisstein (Truman State University;Biology)

2005-12-16

220

EconModel  

NSDL National Science Digital Library

This site contains 21 modular, easy to use economic models, that are appropriate for class assignments or in-class demonstrations. Students can simulate all the standard models taught in most economics courses. EconModel uses the Windows OS. The simulations were developed by William R. Parke of the University of North Carolina at Chapel Hill.

Blecha, Betty J.

221

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

222

Model Breaking Points Conceptualized  

ERIC Educational Resources Information Center

Current curriculum initiatives (e.g., National Governors Association Center for Best Practices and Council of Chief State School Officers 2010) advocate that models be used in the mathematics classroom. However, despite their apparent promise, there comes a point when models break, a point in the mathematical problem space where the model cannot,…

Vig, Rozy; Murray, Eileen; Star, Jon R.

2014-01-01

223

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

224

Scalar Field Gradient Model  

NSDL National Science Digital Library

The Scalar Field Gradient Model displays the gradient of a scalar field using a numerical approximation to the partial derivatives. This simple teaching model also shows how to display and model scalar and vector fields using the EJS. The EJS Scalar Field Gradient 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_math_ScalarFieldGradient.jar file will run the program if Java is installed.

Christian, Wolfgang

2009-03-14

225

Continuous Cellular Automata Model  

NSDL National Science Digital Library

The Continuous Cellular Automata Model creates a one-dimensional array of rational numbers Xi and applies a rule that determines how each cell evolves from one generation to the next. The numerators and denominators of numbers Xi are stored as arbitrary precision Big Integer objects so all computations are exact.  Because arbitrary precision arithmetic is computationally intensive, we use the Parallel Java library to implement the model. The Continuous Cellular Automata Model was developed by Wolfgang Christian using the Easy Java Simulations (Ejs) modeling tool. It is based on the One-Dimensional Continuous Cellular Automata model in Chapter 17 of the book "Building Parallel Programs" by Alan Kaminsky.

Christian, Wolfgang

2012-04-03

226

Models of Abnormal Scarring  

PubMed Central

Keloids and hypertrophic scars are thick, raised dermal scars, caused by derailing of the normal scarring process. Extensive research on such abnormal scarring has been done; however, these being refractory disorders specific to humans, it has been difficult to establish a universal animal model. A wide variety of animal models have been used. These include the athymic mouse, rats, rabbits, and pigs. Although these models have provided valuable insight into abnormal scarring, there is currently still no ideal model. This paper reviews the models that have been developed. PMID:24078916

Seo, Bommie F.; Lee, Jun Yong; Jung, Sung-No

2013-01-01

227

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

228

Pilot model hypothesis testing  

NASA Technical Reports Server (NTRS)

The aircraft control time history predicted by the optimal control pilot model and actual pilot tracking data obtained from NASA Langley's differential maneuvering simulator (DMS) are analyzed. The analysis is performed using a hypothesis testing scheme modified to allow for changes in the true hypothesis. A finite number of pilot models, each with different hypothesized internal model representations of the aircraft dynamics, are constructed. The hypothesis testing scheme determines the relative probability that each pilot model best matches the DMS data. By observing the changes in probabilities, it is possible to determine when the pilot changes control strategy and which hypothesized pilot model best represent's the pilot's control behavior.

Broussard, J. R.; Berry, P. W.

1982-01-01

229

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

230

Modeling agriculture in the Community Land Model  

NASA Astrophysics Data System (ADS)

The potential impact of climate change on agriculture is uncertain. In addition, agriculture could influence above- and below-ground carbon storage. Development of models that represent agriculture is necessary to address these impacts. We have developed an approach to integrate agriculture representations for three crop types - maize, soybean, and spring wheat - into the coupled carbon-nitrogen version of the Community Land Model (CLM), to help address these questions. Here we present the new model, CLM-Crop, validated against observations from two AmeriFlux sites in the United States, planted with maize and soybean. Seasonal carbon fluxes compared well with field measurements for soybean, but not as well for maize. CLM-Crop yields were comparable with observations in countries such as the United States, Argentina, and China, although the generality of the crop model and its lack of technology and irrigation made direct comparison difficult. CLM-Crop was compared against the standard CLM3.5, which simulates crops as grass. The comparison showed improvement in gross primary productivity in regions where crops are the dominant vegetation cover. Crop yields and productivity were negatively correlated with temperature and positively correlated with precipitation, in agreement with other modeling studies. In case studies with the new crop model looking at impacts of residue management and planting date on crop yield, we found that increased residue returned to the litter pool increased crop yield, while reduced residue returns resulted in yield decreases. Using climate controls to signal planting date caused different responses in different crops. Maize and soybean had opposite reactions: when low temperature threshold resulted in early planting, maize responded with a loss of yield, but soybean yields increased. Our improvements in CLM demonstrate a new capability in the model - simulating agriculture in a realistic way, complete with fertilizer and residue management practices. Results are encouraging, with improved representation of human influences on the land surface and the potentially resulting climate impacts.

Drewniak, B.; Song, J.; Prell, J.; Kotamarthi, V. R.; Jacob, R.

2013-04-01

231

Animal models of atherosclerosis.  

PubMed

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

2014-05-16

232

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

233

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

234

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

235

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

236

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

237

Toward Scientific Numerical Modeling  

NASA Technical Reports Server (NTRS)

Ultimately, scientific numerical models need quantified output uncertainties so that modeling can evolve to better match reality. Documenting model input uncertainties and verifying that numerical models are translated into code correctly, however, are necessary first steps toward that goal. Without known input parameter uncertainties, model sensitivities are all one can determine, and without code verification, output uncertainties are simply not reliable. To address these two shortcomings, two proposals are offered: (1) an unobtrusive mechanism to document input parameter uncertainties in situ and (2) an adaptation of the Scientific Method to numerical model development and deployment. Because these two steps require changes in the computational simulation community to bear fruit, they are presented in terms of the Beckhard-Harris-Gleicher change model.

Kleb, Bil

2007-01-01

238

Rail-transportation modeling  

SciTech Connect

Many different types of transportation models are used to model coal transportation by rail. To obtain realistic results, it is usually necessary to consider other modes in addition to rail and other commodities in addition to coal. For example, to know the potential bottlenecks on the rail system it is necessary to predict the total level of freight movement on the rail system. This requires modeling the movements of other commodities in addition to coal. To predict the levels of flows of both coal and non-coal commodities on the rail system, it is necessary to predict the share of total flows carried by rail. This requires accurate modeling of competing modes. To develop accurate rate models it is also necessary to have information on competing modes. This paper presents a collection of transportation models used to model the various aspects of coal transportation by rail and shows how they interact.

Tobin, R.L.

1982-01-01

239

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

240

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 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. Revision 01 ICN 01 included the results of the unqualified software code MULTIFLUX to assess the influence of moisture on the ventilation efficiency. The purposes of Revision 02 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 asses the impacts of moisture on the ventilation efficiency.

V. Chipman; J. Case

2002-12-20

241

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

242

Bayesian Inference for Linear Models  

E-print Network

Bayesian Inference for Linear Models Maximum Likelihood Linear Models fMRI analysis Bayesian Linear Inference for Linear Models Maximum Likelihood Linear Models fMRI analysis Bayesian Linear Models fMRI Linear Models fMRI analysis Bayesian Linear Models fMRI example Augmented Form MAP Learning MEG Source

Penny, Will

243

Modeling agriculture in the Community Land Model  

NASA Astrophysics Data System (ADS)

The potential impact of climate change on agriculture is uncertain. In addition, agriculture could influence above- and below-ground carbon storage. Development of models that represent agriculture is necessary to address these impacts. We have developed an approach to integrate agriculture representations for three crop types - maize, soybean, and spring wheat - into the coupled carbon-nitrogen version of the Community Land Model (CLM), to help address these questions. Here we present the new model, CLM-Crop, validated against observations from two AmeriFlux sites in the United States, planted with maize and soybean. Seasonal carbon fluxes compared well with field measurements. CLM-Crop yields were comparable with observations in some regions, although the generality of the crop model and its lack of technology and irrigation made direct comparison difficult. CLM-Crop was compared against the standard CLM3.5, which simulates crops as grass. The comparison showed improvement in gross primary productivity in regions where crops are the dominant vegetation cover. Crop yields and productivity were negatively correlated with temperature and positively correlated with precipitation. In case studies with the new crop model looking at impacts of residue management and planting date on crop yield, we found that increased residue returned to the litter pool increased crop yield, while reduced residue returns resulted in yield decreases. Using climate controls to signal planting date caused different responses in different crops. Maize and soybean had opposite reactions: when low temperature threshold resulted in early planting, maize responded with a loss of yield, but soybean yields increased. Our improvements in CLM demonstrate a new capability in the model - simulating agriculture in a realistic way, complete with fertilizer and residue management practices. Results are encouraging, with improved representation of human influences on the land surface and the potentially resulting climate impacts.

Drewniak, B.; Song, J.; Prell, J.; Kotamarthi, V. R.; Jacob, R.

2012-12-01

244

The Earth System Model  

NASA Technical Reports Server (NTRS)

The Earth System Model is the natural evolution of current climate models and will be the ultimate embodiment of our geophysical understanding of the planet. These models are constructed from components - atmosphere, ocean, ice, land, chemistry, solid earth, etc. models and merged together through a coupling program which is responsible for the exchange of data from the components. Climate models and future earth system models will have standardized modules, and these standards are now being developed by the ESMF project funded by NASA. The Earth System Model will have a variety of uses beyond climate prediction. The model can be used to build climate data records making it the core of an assimilation system, and it can be used in OSSE experiments to evaluate. The computing and storage requirements for the ESM appear to be daunting. However, the Japanese ES theoretical computing capability is already within 20% of the minimum requirements needed for some 2010 climate model applications. Thus it seems very possible that a focused effort to build an Earth System Model will achieve succcss.

Schoeberl, Mark; Rood, Richard B.; Hildebrand, Peter; Raymond, Carol

2003-01-01

245

Preliminary DIAL model  

SciTech Connect

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.

1994-06-01

246

Introduction to Climate Models  

NSDL National Science Digital Library

This module explains how climate models work. Because the modeling of both weather and climate share many similarities, the content throughout this module draws frequent comparisons and highlights the differences. We explain not only how, but why climate models differ from weather models. To do so, we explore the difference between weather and climate, then show how models are built to simulate climate and generate the statistics that describe it. We conclude with a discussion of models are tuned and tested. Understanding how climate responds to changes in atmospheric composition and other factors drives climate research. Climate models provide a tool to understand how processes work and interact with each other. Our intended audience is the weather forecasting community: those who are already familiar with NWP models. Non-forecasters with an interest in weather and climate should also find the module useful. The content is not overly technical and the goal of this module is not to train people to develop climate models but to highlight the similarities and differences between weather and climate models.

Comet

2012-09-19

247

[Mathematical models of hysteresis  

SciTech Connect

The research described in this proposal is currently being supported by the US Department of Energy under the contract Mathematical Models of Hysteresis''. Thus, before discussing the proposed research in detail, it is worthwhile to describe and summarize the main results achieved in the course of our work under the above contract. Our ongoing research has largely been focused on the development of mathematical models of hysteretic nonlinearities with nonlocal memories''. The distinct feature of these nonlinearities is that their current states depend on past histories of input variations. It turns out that memories of hysteretic nonlinearities are quite selective. Indeed, experiments show that only some past input extrema leave their marks upon future states of hysteretic nonlinearities. Thus special mathematical tools are needed in order to describe nonlocal selective memories of hysteretic nonlinearities. Our research has been primarily concerned with Preisach-type models of hysteresis. All these models have a common generic feature; they are constructed as superpositions of simplest hysteretic nonlinearities-rectangular loops. Our study has by and large been centered around the following topics: various generalizations and extensions of the classical Preisach model, finding of necessary and sufficient conditions for the representation of actual hysteretic nonlinearities by various Preisach type models, solution of identification problems for these models, numerical implementation and experimental testing of Preisach type models. Although the study of Preisach type models has constituted the main direction of the research, some effort has also been made to establish some interesting connections between these models and such topics as: the critical state model for superconducting hysteresis, the classical Stoner-Wohlfarth model of vector magnetic hysteresis, thermal activation type models for viscosity, magnetostrictive hysteresis and neural networks.

Mayergoyz, I.D.

1991-01-01

248

The Protein Model Portal.  

PubMed

Structural Genomics has been successful in determining the structures of many unique proteins in a high throughput manner. Still, the number of known protein sequences is much larger than the number of experimentally solved protein structures. Homology (or comparative) modeling methods make use of experimental protein structures to build models for evolutionary related proteins. Thereby, experimental structure determination efforts and homology modeling complement each other in the exploration of the protein structure space. One of the challenges in using model information effectively has been to access all models available for a specific protein in heterogeneous formats at different sites using various incompatible accession code systems. Often, structure models for hundreds of proteins can be derived from a given experimentally determined structure, using a variety of established methods. This has been done by all of the PSI centers, and by various independent modeling groups. The goal of the Protein Model Portal (PMP) is to provide a single portal which gives access to the various models that can be leveraged from PSI targets and other experimental protein structures. A single interface allows all existing pre-computed models across these various sites to be queried simultaneously, and provides links to interactive services for template selection, target-template alignment, model building, and quality assessment. The current release of the portal consists of 7.6 million model structures provided by different partner resources (CSMP, JCSG, MCSG, NESG, NYSGXRC, JCMM, ModBase, SWISS-MODEL Repository). The PMP is available at http://www.proteinmodelportal.org and from the PSI Structural Genomics Knowledgebase. PMID:19037750

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

2009-03-01

249

Hindmarsh-Rose Model  

NSDL National Science Digital Library

The Hindmarsh-Rose model is a system of three differential equations that model a different physical aspect of a single neuron. The three dynamical variables in this model, x, y, and z represent respectively the membrane potential, the activity of fast gated ion channels (such as sodium and potassium), and the activity of slow-gated ion channels (such as calcium and chloride). The Hindmarsh-Rose 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.

Thomson, Colin F.

2012-11-06

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

Teaching macromolecular modeling.  

PubMed Central

Training newcomers to the field of macromolecular modeling is as difficult as is training beginners in x-ray crystallography, nuclear magnetic resonance, or other methods in structural biology. In one or two lectures, the most that can be conveyed is a general sense of the relationship between modeling and other structural methods. If a full semester is available, then students can be taught how molecular structures are built, manipulated, refined, and analyzed on a computer. Here we describe a one-semester modeling course that combines lectures, discussions, and a laboratory using a commercial modeling package. In the laboratory, students carry out prescribed exercises that are coordinated to the lectures, and they complete a term project on a modeling problem of their choice. The goal is to give students an understanding of what kinds of problems can be attacked by molecular modeling methods and which problems are beyond the current capabilities of those methods. PMID:1489919

Harvey, S C; Tan, R K

1992-01-01

252

Modeling of compressible turbulence  

NASA Technical Reports Server (NTRS)

The work is directed toward understanding and modeling compressibility effects in turbulent flows. The primary objective is to investigate how compressibility influences the basic turbulence processes such as turbulence production and dissipation, length scale modification, spectral energy transfer, etc. The second objective is to develop parameterization schemes and models to incorporate compressibility into one-point closure models and into the subgrid scale models for LES techniques. The ultimate purpose of this research is to develop compressible turbulence models which are capable of handling the hypersonic regime. Specifically, the emphasis will be on the model capability of predicting: (1) heat and momentum transfer in hypersonic boundary layers; and (2) mixing and growth of high Mach number shear layers, jet and wakes.

Zeman, O.

1990-01-01

253

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

254

Spray combustor modelling  

NASA Astrophysics Data System (ADS)

Mathematical modeling and experimental measurements are presented for a gas turbine combustor can. The mathematical model is of the finite difference type. It includes an algebraic stress model for turbulence, combustion models of the Magnussen type and a detailed fuel spray model. The latter employs a Lagrangian, droplet tracking, technique. Here the effect of slip, between the gas and liquid phase, is included as well as the effect of turbulence on droplets. The experimental data includes temperature, gas composition and velocity profiles. Satisfactory agreement has been obtained between measurement and prediction. It is concluded that: (1) the shear stress modeling coefficients used for isothermal flow can be used without adjustment for combustion and (2) turbulence has a significant effect on the fuel spray distribution in this combustor.

Wild, P. N.; Boysan, F.; Swithenbank, J.

255

The Everglades Landscape Model  

NSDL National Science Digital Library

Developed by researchers at the Institute for Ecological Economics and the South Florida Water Management District, the Everglades Landscape Model is one of the tools in a research management program used to focus research and evaluate changes in water management of southern Florida. The site has a brief introduction to the problems involved with the management of the region and the general objectives of the project. In addition, there is a detailed section outlining the particulars of the model's structure and the specific premises assumed within the model. There is also a full list of related publications dealing with different projects involved with the model and various progress reports. Finally, a variety of data generated by the model and data used to run the model is available for visitors to the site.

256

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

257

The model coupling toolkit.  

SciTech Connect

The advent of coupled earth system models has raised an important question in parallel computing: What is the most effective method for coupling many parallel models to form a high-performance coupled modeling system? We present our solution to this problem--The Model Coupling Toolkit (MCT). We explain how our effort to construct the Next-Generation Coupler for NCAR Community Climate System Model motivated us to create this toolkit. We describe in detail the conceptual design of the MCT and explain its usage in constructing parallel coupled models. We present preliminary performance results for the toolkit's parallel data transfer facilities. Finally, we outline an agenda for future development of the MCT.

Larson, J. W.; Jacob, R. L.; Foster, I.; Guo, J.

2001-04-13

258

Decomposing model systematic error  

NASA Astrophysics Data System (ADS)

Seasonal forecasts made with a single model are generally overconfident. The standard approach to improve forecast reliability is to account for structural uncertainties through a multi-model ensemble (i.e., an ensemble of opportunity). Here we analyse a multi-model set of seasonal forecasts available through ENSEMBLES and DEMETER EU projects. We partition forecast uncertainties into initial value and structural uncertainties, as function of lead-time and region. Statistical analysis is used to investigate sources of initial condition uncertainty, and which regions and variables lead to the largest forecast error. Similar analysis is then performed to identify common elements of model error. Results of this analysis will be used to discuss possibilities to reduce forecast uncertainty and improve models. In particular, better understanding of error growth will be useful for the design of interactive multi-model ensembles.

Keenlyside, Noel; Shen, Mao-Lin

2014-05-01

259

Modelling the geomagnetic field  

NASA Astrophysics Data System (ADS)

A review is presented of the manner in which models of the geomagnetic field are produced. The data on which spherical harmonic models of the main geomagnetic field and its secular variation are used by scientists and engineers studying the earth's interior, its ionosphere and magnetosphere, must be of the highest quality and must be distributed as homogeneously as possible worldwide. As the quality of a model is dependent on the quality of the data on which it is based, sources of data for secular-variation and for main-field modeling are discussed in detail. The methods presently utilized for producing spherical harmonic models are described and some estimates of the accuracies of some recent geomagnetic field models are given.

Barraclough, D. R.

260

Multiscale cancer modeling.  

PubMed

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 insights in 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

Deisboeck, Thomas S; Wang, Zhihui; Macklin, Paul; Cristini, Vittorio

2011-08-15

261

AREST model description  

SciTech Connect

The Office of Civilian Radioactive Waste Management and the Power Reactor and Nuclear Fuel Development Corporation of Japan (PNC) have supported the development of the Analytical Repository Source-Term (AREST) at Pacific Northwest Laboratory. AREST is a computer model developed to evaluate radionuclide release from an underground geologic repository. The AREST code can be used to calculate/estimate the amount and rate of each radionuclide that is released from the engineered barrier system (EBS) of the repository. The EBS is the man-made or disrupted area of the repository. AREST was designed as a system-level models to simulate the behavior of the total repository by combining process-level models for the release from an individual waste package or container. AREST contains primarily analytical models for calculating the release/transport of radionuclides to the lost rock that surrounds each waste package. Analytical models were used because of the small computational overhead that allows all the input parameters to be derived from a statistical distribution. Recently, a one-dimensional numerical model was also incorporated into AREST, to allow for more detailed modeling of the transport process with arbitrary length decay chains. The next step in modeling the EBS, is to develop a model that couples the probabilistic capabilities of AREST with a more detailed process model. This model will need to look at the reactive coupling of the processes that are involved with the release process. Such coupling would include: (1) the dissolution of the waste form, (2) the geochemical modeling of the groundwater, (3) the corrosion of the container overpacking, and (4) the backfill material, just to name a few. Several of these coupled processes are already incorporated in the current version of AREST.

Engel, D.W.; McGrail, B.P.

1993-11-01

262

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

263

Atmospheric prediction model survey  

NASA Technical Reports Server (NTRS)

As part of the SEASAT Satellite program of NASA, a survey of representative primitive equation atmospheric prediction models that exist in the world today was written for the Jet Propulsion Laboratory. Seventeen models developed by eleven different operational and research centers throughout the world are included in the survey. The surveys are tutorial in nature describing the features of the various models in a systematic manner.

Wellck, R. E.

1976-01-01

264

Towards Tangible Work Modeling  

Microsoft Academic Search

Digital Montessori-inspired Manipulatives (MiMs) so far have been used effectively for knowledge transfer in elementary educational settings. For work modeling and task-based interactive systems design we propose a modeling concept and usage scenario that should help to increase effectiveness in organization and technology development. The Tangible Task Modeling Demonstrator (TTMD) facili- tates the representation and development of work and task

Stefan Oppl; Christian Stary; Andreas Auinger

2006-01-01

265

Towards Tangible Work Modelling  

Microsoft Academic Search

Digital Montessori-inspired Manipulatives (MiMs), so far have been used effectively for knowledge transfer in elementary educational settings. For work modelling and task-based interactive systems design we propose a modelling concept and usage scenario that should help to increase effectiveness in organization and technology development. The Tangible Task Modelling Demonstrator (TTMD) facili- tates the representation and development of work and task

Stefan Oppl; Christian Stary; Andreas Auinger; Johannes Kepler

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

Area Models: Multiplying Fractions  

NSDL National Science Digital Library

In this lesson students will investigate relationship between area models and the concept of multiplying fractions. Students will use area model to develop understanding of the concept of multiplying fractions as well as to find the product of two common fraction. The teacher will use the free application GeoGebra (see download link under Suggested Technology) to provide students with a visual representation of how area models can be used at the time of multiplying fractions.

2012-11-05

268

Solid model design simplification  

SciTech Connect

This paper documents an investigation of approaches to improving the quality of Pro/Engineer-created solid model data for use by downstream applications. The investigation identified a number of sources of problems caused by deficiencies in Pro/Engineer`s geometric engine, and developed prototype software capable of detecting many of these problems and guiding users towards simplified, useable models. The prototype software was tested using Sandia production solid models, and provided significant leverage in attacking the simplification problem.

Ames, A.L.; Rivera, J.J.; Webb, A.J.; Hensinger, D.M.

1997-12-01

269

Rat endovascular perforation model.  

PubMed

Experimental animal models of aneurysmal subarachnoid hemorrhage (SAH) have provided a wealth of information on the mechanisms of brain injury. The rat endovascular perforation (EVP) model replicates the early pathophysiology of SAH and hence is frequently used to study early brain injury following SAH. This paper presents a brief review of historical development of the EVP model and details the technique used to create SAH and considerations necessary to overcome technical challenges. PMID:25213427

Sehba, Fatima A

2014-12-01

270

Battle of Animal Models  

Microsoft Academic Search

This is a brief summary of the animal models session held during the 12th Annual Meeting of the Society on NeuroImmune Pharmacology,\\u000a Santa Fe, NM, USA. This session provided important information for participants on availability and utility of animal models\\u000a for the studies of HIV-1 central nervous system infection and drug abuse. It highlighted animal model relevance to human disease\\/condition,

Yuri Persidsky; Howard Fox

2007-01-01

271

INEEL Air Modeling Protocol  

Microsoft Academic Search

ABSTRACT Various laws stemming,from the Clean Air Act of 1970 and the Clean Air Act amendments,of 1990 require air emissions modeling. Modeling is used to ensure that air emissions from new projects and from modifications to existing facilities do not exceed certain standards. For radionuclides, any new airborne release must be modeled to show that downwind,receptors do not receive exposures

C. S. Staley; M. L. Abbott; P. D. Ritter

272

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.

Gregory L. Vogt, Ed D.; Moreno, Nancy P.

2011-01-01

273

F-14 modeling study  

NASA Technical Reports Server (NTRS)

Preliminary results in the application of a closed loop pilot/simulator model to the analysis of some simulator fidelity issues are discussed in the context of an air to air target tracking task. The closed loop model is described briefly. Then, problem simplifications that are employed to reduce computational costs are discussed. Finally, model results showing sensitivity of performance to various assumptions concerning the simulator and/or the pilot are presented.

Levison, W. H.; Baron, S.

1984-01-01

274

Model Analyses and Guidance  

NSDL National Science Digital Library

This site from the NOAA provides graphics for forecast models including: the ETA, the Global Forecast System (GFS), the Wave Watch III (WW3), the Nested Grid model (NGM), and the Rapid Update Cycle (RUC). Outputs are available for North America, North Pacific, Western North Atlantic, and the Polar Ice Drift. Users can find links to detailed descriptions of the inputs and history of each model.

2008-03-27

275

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

276

Spherical Mirror Model  

NSDL National Science Digital Library

The Spherical Mirror Model demonstrates the focusing of light using a spherical mirror. The user can change the size and position of the object, the focal length of the mirror and the rays shown in the diagram. The Spherical Mirror 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_Spherical_Mirror.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-25

277

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

278

Ceiling Bounce Model  

NSDL National Science Digital Library

The EJS Ceiling Bounce Model shows a ball launched by a spring-gun in a building with a very high ceiling and a graph of the ball's position or velocity as a function of time. Students are asked set the ball's inital velocity so that it barely touches the ceiling. This simple model is  a designed to teach both physics and EJS modeling.

Christian, Wolfgang

2008-12-16

279

Modeling Instruction Program  

NSDL National Science Digital Library

Created by David Hestenes of Arizona State University's modeling instruction and software development research, this site is an approach to reform of curriculum design and teaching methodology has been guided by a Modeling Theory of Physics Instruction. In addition, the site also provides modeling instructions for biology, chemistry and physical science. External links are provided under the heading "Opportunities for Professional Growth." These allow teachers the opportunity for explore workshops and other programs which can help enhance their teaching/curriculum.

Hestenes, David; Jackson, Jane

2009-04-20

280

Model Publication Scheme Model Publication Scheme  

E-print Network

an authority to make information available to the public as part of its normal business activities, assessments, inspections and reviews. April 2008 1 #12;Model Publication Scheme V1.0 How we make decisions. Policy proposals and decisions. Decision making processes, internal criteria and procedures

Sussex, University of

281

The ECW Model  

NASA Astrophysics Data System (ADS)

The ECW model is a powerful tool for developing an understanding of donor-acceptor interactions. Most modern inorganic chemistry textbooks discuss the model's ability to correlate and predict enthalpies of adduct formation but overlook the application of the E and C parameters as a scale to analyze reactivity and spectroscopy. Furthermore, a survey of these textbooks indicate the authors are using parameters of different vintages. This article provides the teacher with the latest parameters as well as an update of the traditional uses of the ECW model and a discussion of some of the more important, often overlooked, applications of the model.

Vogel, Glenn C.; Drago, Russell S.

1996-08-01

282

Model Error Budgets  

NASA Technical Reports Server (NTRS)

An error budget is a commonly used tool in design of complex aerospace systems. It represents system performance requirements in terms of allowable errors and flows these down through a hierarchical structure to lower assemblies and components. The requirements may simply be 'allocated' based upon heuristics or experience, or they may be designed through use of physics-based models. This paper presents a basis for developing an error budget for models of the system, as opposed to the system itself. The need for model error budgets arises when system models are a principle design agent as is increasingly more common for poorly testable high performance space systems.

Briggs, Hugh C.

2008-01-01

283

Structural model integrity  

NASA Technical Reports Server (NTRS)

Many of the practical aspects and problems of ensuring the integrity of a structural model are discussed, as well as the steps which have been taken in the NASTRAN system to assure that these checks can be routinely performed. Model integrity as used applies not only to the structural model but also to the loads applied to the model. Emphasis is also placed on the fact that when dealing with substructure analysis, all of the checking procedures discussed should be applied at the lowest level of substructure prior to any coupling.

Wallerstein, D. V.; Lahey, R. S.; Haggenmacher, G. W.

1977-01-01

284

A Quasar Wind Model  

E-print Network

A quasar wind model is proposed to describe the spatial and velocity structure of the broad line region. This model requires detailed photoionization and magnetohydrodynamic simulation, as the broad line region it too small for direct spatial resolution. The emission lines are Doppler broadened, since the gas is moving at high velocity. The high velocity is attained by the gas from a combination of radiative and magnetic driving forces. Once this model is complete, the model predictions will be tested against recent microlensing data in conjunction with diverse existing observations.

Andrea Ruff

2008-09-16

285

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

286

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

287

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

288

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

289

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.

Center, Nasa: C.; Nasa

290

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

291

Prime Counting Function Model  

NSDL National Science Digital Library

The Prime Counting Function model uses the trial division algorithm to compute the number of primes less than or equal to the number n. Although the trial division algorithm is inefficient, we use it to perform a lengthy calculation while a standard EJS simulation thread accumulates and plots data from the parallel computation. Users can vary the number of independent threads and observe the computational time. The Prime Counting Function 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 model's jar file will run the simulation if Java is installed.

Christian, Wolfgang

2013-10-11

292

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

293

Fibonacci Sphere Model  

NSDL National Science Digital Library

The Fibonacci Sphere Model draws n equidistant points on a sphere by distributing the points on a Fibonacci spiral. The sequence the produces this distribution separates advances the longitude by the golden angle. The Fibonacci Sphere 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

2012-12-16

294

Mathematical model of sarcoidosis.  

PubMed

Sarcoidosis is a disease involving abnormal collection of inflammatory cells forming nodules, called granulomas. Such granulomas occur in the lung and the mediastinal lymph nodes, in the heart, and in other vital and nonvital organs. The origin of the disease is unknown, and there are only limited clinical data on lung tissue of patients. No current model of sarcoidosis exists. In this paper we develop a mathematical model on the dynamics of the disease in the lung and use patients' lung tissue data to validate the model. The model is used to explore potential treatments. PMID:25349384

Hao, Wenrui; Crouser, Elliott D; Friedman, Avner

2014-11-11

295

Particle bed reactor modeling  

NASA Technical Reports Server (NTRS)

The topics are presented in viewgraph form and include the following: particle bed reactor (PBR) core cross section; PBR bleed cycle; fuel and moderator flow paths; PBR modeling requirements; characteristics of PBR and nuclear thermal propulsion (NTP) modeling; challenges for PBR and NTP modeling; thermal hydraulic computer codes; capabilities for PBR/reactor application; thermal/hydralic codes; limitations; physical correlations; comparison of predicted friction factor and experimental data; frit pressure drop testing; cold frit mask factor; decay heat flow rate; startup transient simulation; and philosophy of systems modeling.

Sapyta, Joe; Reid, Hank; Walton, Lew

1993-01-01

296

Model Transformation by Partial Evaluation of Model Interpreters  

Microsoft Academic Search

In model-driven development, the use of both model translators and model interpreters is widespread. It is also well-known that partial evaluation can turn an interpreter into a translator. In this paper we show t hat a simple online partial evaluator is effective at specializing a model inte rpreter with respect to a model to create a compiled model interpretation. Data

William R. Cook; Benjamin Delaware; Thomas Finsterbusch; Ali Ibrahim; Ben Wiedermann

297

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.

298

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

299

Human Motor Computational Model Through Iterative Model Reference Adaptive Control  

E-print Network

Human Motor Computational Model Through Iterative Model Reference Adaptive Control Shou-Han Zhou observed in the human motor adaptation. Keywords: Human Motor Computational Model; Iterative Model.burdet@imperial.ac.uk). Abstract: A computational model using mechanical impedance control in combination with an iterative model

Melbourne, University of

300

Hydrodynamic modeling of Lake Ontario: An intercomparison of three models  

Microsoft Academic Search

The solutions of three lake hydrodynamic models, namely, Princeton Ocean Model (POM), Canadian Version of Diecast Model, and Estuary, Lake, and Coastal Ocean Model, are compared with each other and with observations in Lake Ontario. The models have the same horizontal resolution and are forced with meteorological observations during mid-April to early October of 2006. The three models obtained qualitatively

Anning Huang; Yerubandi R. Rao; Youyu Lu; Jun Zhao

2010-01-01

301

Groundwater Model Validation  

SciTech Connect

Models have an inherent uncertainty. The difficulty in fully characterizing the subsurface environment makes uncertainty an integral component of groundwater flow and transport models, which dictates the need for continuous monitoring and improvement. Building and sustaining confidence in closure decisions and monitoring networks based on models of subsurface conditions require developing confidence in the models through an iterative process. The definition of model validation is postulated as a confidence building and long-term iterative process (Hassan, 2004a). Model validation should be viewed as a process not an end result. Following Hassan (2004b), an approach is proposed for the validation process of stochastic groundwater models. The approach is briefly summarized herein and detailed analyses of acceptance criteria for stochastic realizations and of using validation data to reduce input parameter uncertainty are presented and applied to two case studies. During the validation process for stochastic models, a question arises as to the sufficiency of the number of acceptable model realizations (in terms of conformity with validation data). Using a hierarchical approach to make this determination is proposed. This approach is based on computing five measures or metrics and following a decision tree to determine if a sufficient number of realizations attain satisfactory scores regarding how they represent the field data used for calibration (old) and used for validation (new). The first two of these measures are applied to hypothetical scenarios using the first case study and assuming field data consistent with the model or significantly different from the model results. In both cases it is shown how the two measures would lead to the appropriate decision about the model performance. Standard statistical tests are used to evaluate these measures with the results indicating they are appropriate measures for evaluating model realizations. The use of validation data to constrain model input parameters is shown for the second case study using a Bayesian approach known as Markov Chain Monte Carlo. The approach shows a great potential to be helpful in the validation process and in incorporating prior knowledge with new field data to derive posterior distributions for both model input and output.

Ahmed E. Hassan

2006-01-24

302

Model Based Temporal Reasoning  

NASA Astrophysics Data System (ADS)

Systems that assess the real world must cope with evidence that is uncertain, ambiguous, and spread over time. Typically, the most important function of an assessment system is to identify when activities are occurring that are unusual or unanticipated. Model based temporal reasoning addresses both of these requirements. The differences among temporal reasoning schemes lies in the methods used to avoid computational intractability. If we had n pieces of data and we wanted to examine how they were related, the worst case would be where we had to examine every subset of these points to see if that subset satisfied the relations. This would be 2n, which is intractable. Models compress this; if several data points are all compatible with a model, then that model represents all those data points. Data points are then considered related if they lie within the same model or if they lie in models that are related. Models thus address the intractability problem. They also address the problem of determining unusual activities if the data do not agree with models that are indicated by earlier data then something out of the norm is taking place. The models can summarize what we know up to that time, so when they are not predicting correctly, either something unusual is happening or we need to revise our models. The model based reasoner developed at Advanced Decision Systems is thus both intuitive and powerful. It is currently being used on one operational system and several prototype systems. It has enough power to be used in domains spanning the spectrum from manufacturing engineering and project management to low-intensity conflict and strategic assessment.

Rabin, Marla J.; Spinrad, Paul R.; Fall, Thomas C.

1988-03-01

303

Why business models matter.  

PubMed

"Business model" was one of the great buzz-words of the Internet boom. A company didn't need a strategy, a special competence, or even any customers--all it needed was a Web-based business model that promised wild profits in some distant, ill-defined future. Many people--investors, entrepreneurs, and executives alike--fell for the fantasy and got burned. And as the inevitable counterreaction played out, the concept of the business model fell out of fashion nearly as quickly as the .com appendage itself. That's a shame. As Joan Magretta explains, a good business model remains essential to every successful organization, whether it's a new venture or an established player. To help managers apply the concept successfully, she defines what a business model is and how it complements a smart competitive strategy. Business models are, at heart, stories that explain how enterprises work. Like a good story, a robust business model contains precisely delineated characters, plausible motivations, and a plot that turns on an insight about value. It answers certain questions: Who is the customer? How do we make money? What underlying economic logic explains how we can deliver value to customers at an appropriate cost? Every viable organization is built on a sound business model, but a business model isn't a strategy, even though many people use the terms interchangeably. Business models describe, as a system, how the pieces of a business fit together. But they don't factor in one critical dimension of performance: competition. That's the job of strategy. Illustrated with examples from companies like American Express, EuroDisney, WalMart, and Dell Computer, this article clarifies the concepts of business models and strategy, which are fundamental to every company's performance. PMID:12024761

Magretta, Joan

2002-05-01

304

Epidemic modeling techniques for smallpox  

E-print Network

Infectious disease models predict the impact of outbreaks. Discrepancies between model predictions stem from both the disease parameters used and the underlying mathematics of the models. Smallpox has been modeled extensively ...

McLean, Cory Y. (Cory Yuen Fu)

2004-01-01

305

Model selection in compositional spaces  

E-print Network

We often build complex probabilistic models by composing simpler models-using one model to generate parameters or latent variables for another model. This allows us to express complex distributions over the observed data ...

Grosse, Roger Baker

2014-01-01

306

Area Model for Division  

NSDL National Science Digital Library

This lesson plan helps students understand multi-digit division by constructing area models. The included interactive provides two example problems and helps connect the model to the traditional long division algorithm. Students solve their own problems using graph paper and/or base-10 blocks and progress toward mental strategies.

2014-01-01

307

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

308

Modeling of respiratory crackles  

Microsoft Academic Search

Crackles, extracted from lung sounds recorded from pathological subjects, are parameterized using Prony modeling of order two. The scatter plots of Prony parameters show that there is a correlation between the type of pathology and the lung volume of crackle occurrence and the Prony frequencies. These distinctive distributions of crackle populations of each disease indicate that Prony modeling generates crackle

Yasemin P. Kahya; C. Asli Yilmaz

2000-01-01

309

Modeling Negotiation Dialogs  

Microsoft Academic Search

For various purposes in the Verbmobil system it is necessary to build a full model of an unfolding dialog, on a suitably abstract level of representation. The basis of this model are representations of the individual utterances, and we capture their content by a combination of dialog act and propositional content. Our hierar- chy of dialog acts was used to

Jan Alexandersson; Ralf Engel; Michael Kipp; Stephan Koch; Norbert Reithinger; Manfred Stede

310

AIRMS infrared performance model  

Microsoft Academic Search

A well designed performance modeling tool can assess trade- offs in sensor parameters for design; reasonably predict performance for varied targets, geometries, backgrounds, and environments; diagnose sensor system and signal processing problems, and provide a valued remote sensing educational tool. This paper describes the Infrared Performance Model (IRPM) which predicts IRST (Infrared Search and Track) detection SNRs for ranges of

Kenneth A. Melendez; Michael Koligman; Robert W. Fries

1997-01-01

311

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

312

Modeling Internet topology  

Microsoft Academic Search

The topology of a network, or a group of networks such as the Internet, has a strong bearing on many management and performance issues. Good models of the topological structure of a network are essential for developing and analyzing internetworking technology. This article discusses how graph-based models can be used to represent the topology of large networks, particularly aspects of

K. I. Calvert; M. B. Doar; E. W. Zegura

1997-01-01

313

PHOTOCHEMICAL BOX MODEL (PBM)  

EPA Science Inventory

This magnetic tape contains the FORTRAN source code, sample input data, and sample output data for the Photochemical Box Model (PBM). The PBM is a simple stationary single-cell model with a variable height lid designed to provide volume-integrated hour averages of O3 and other ph...

314

Modeling for Insights  

SciTech Connect

System Dynamics is a computer-aided approach to evaluating the interrelationships of different components and activities within complex systems. Recently, System Dynamics models have been developed in areas such as policy design, biological and medical modeling, energy and the environmental analysis, and in various other areas in the natural and social sciences. The real power of System Dynamic modeling is gaining insights into total system behavior as time, and system parameters are adjusted and the effects are visualized in real time. System Dynamic models allow decision makers and stakeholders to explore long-term behavior and performance of complex systems, especially in the context of dynamic processes and changing scenarios without having to wait decades to obtain field data or risk failure if a poor management or design approach is used. The Idaho National Laboratory recently has been developing a System Dynamic model of the US Nuclear Fuel Cycle. The model is intended to be used to identify and understand interactions throughout the entire nuclear fuel cycle and suggest sustainable development strategies. This paper describes the basic framework of the current model and presents examples of useful insights gained from the model thus far with respect to sustainable development of nuclear power.

Jacob J. Jacobson; Gretchen Matthern

2007-04-01

315

Social Modeling and i  

Microsoft Academic Search

Many different types of models are used in various scientific and engineering fields, reflecting the subject matter and the kinds of understanding that is sought in each field. Conceptual modeling techniques in software and information systems engineering have in the past focused mainly on describing and analyzing behaviours and structures that are implementable in software. As software systems become ever

Eric S. K. Yu

2009-01-01

316

Mathematical models of hysteresis  

SciTech Connect

The ongoing research has largely been focused on the development of mathematical models of hysteretic nonlinearities with nonlocal memories. The distinct feature of these nonlinearities is that their current states depend on past histories of input variations. It turns out that memories of hysteretic nonlinearities are quite selective. Indeed, experiments show that only some past input extrema (not the entire input variations) leave their marks upon future states of hysteretic nonlinearities. Thus special mathematical tools are needed in order to describe nonlocal selective memories of hysteretic nonlinearities. The origin of such tools can be traced back to the landmark paper of Preisach. Their research has been primarily concerned with Preisach-type models of hysteresis. All these models have a common generic feature; they are constructed as superpositions of simplest hysteretic nonlinearities-rectangular loops. During the past four years, the study has been by and large centered around the following topics: (1) further development of Scalar and vector Preisach-type models of hysteresis; (2) experimental testing of Preisach-type models of hysteresis; (3) development of new models for viscosity (aftereffect) in hysteretic systems; (4) development of mathematical models for superconducting hysteresis in the case of gradual resistive transitions; (5) software implementation of Preisach-type models of hysteresis; and (6) development of new ideas which have emerged in the course of the research work. The author briefly describes the main scientific results obtained in the areas outlined above.

NONE

1998-08-01

317

Stereolithography models. Final report  

SciTech Connect

This report describes the first stereolithographic models made, which proved in a new release of ProEngineer software (Parametric Technologies, or PTC) and 3D Systems (Valencia, California) software for the SLA 250 machine. They are a model of benzene and the {alpha}-carbon backbone of the variable region of an antibody.

Smith, R.E.

1995-03-01

318

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

319

Making Insect Models.  

ERIC Educational Resources Information Center

Suggests making insect models to learn more about the world of insects. List of materials needed and recommended procedures are provided. Also suggests other interdisciplinary activities for investigating insects in the classroom, including the preparation of an insect zoo using the student-constructed models. (BC)

Sutherland, Betsy

1984-01-01

320

MODELING THE AMES TEST  

EPA Science Inventory

Despite the value and widespread use of the Ames test, little attention has been focused on standardizing quantitative methods of analyzing these data. In this paper, a realistic and statistically tractable model is developed for the evaluation of Ames-type data. The model assume...

321

Using the Partnership Model.  

ERIC Educational Resources Information Center

This paper provides a case study of the use of the Partnership Model in the development of a film about female menopause. Not only are the film maker and the client involved in the trust based partnership relationship, but the film subjects and audience are also included in the information sharing process. Advantages of the Partnership Model

Wilks, Bob

322

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

323

The EMEFS model evaluation  

SciTech Connect

The binational Eulerian Model Evaluation Field Study (EMEFS) consisted of several coordinated data gathering and model evaluation activities. In the EMEFS, data were collected by five air and precipitation monitoring networks between June 1988 and June 1990. Model evaluation is continuing. This interim report summarizes the progress made in the evaluation of the Regional Acid Deposition Model (RADM) and the Acid Deposition and Oxidant Model (ADOM) through the December 1990 completion of a State of Science and Technology report on model evaluation for the National Acid Precipitation Assessment Program (NAPAP). Because various assessment applications of RADM had to be evaluated for NAPAP, the report emphasizes the RADM component of the evaluation. A protocol for the evaluation was developed by the model evaluation team and defined the observed and predicted values to be used and the methods by which the observed and predicted values were to be compared. Scatter plots and time series of predicted and observed values were used to present the comparisons graphically. Difference statistics and correlations were used to quantify model performance. 64 refs., 34 figs., 6 tabs.

Barchet, W.R. (Pacific Northwest Lab., Richland, WA (United States)); Dennis, R.L. (Environmental Protection Agency, Research Triangle Park, NC (United States)); Seilkop, S.K. (Analytical Sciences, Inc., Durham, NC (United States)); Banic, C.M.; Davies, D.; Hoff, R.M.; Macdonald, A.M.; Mickle, R.E.; Padro, J.; Puckett, K. (Atmospheric Environment Service, Downsview, ON (Canada)); Byun, D.; McHenry, J.N.

1991-12-01

324

Samsung card lending model  

Microsoft Academic Search

Samsung Card Lending Model (SCLM) analyzes cash flow in individual accounts and measures the level of company-wide risk. Serving as a risk and portfolio management model in the consumer lending business, the main features of SCLM are as follows. Default ratios such as intrinsic balance default probability and annual default ratio are computed using the past, present, and future cash

Jaeyung Huh; Woojin Chang; Junghoon Lee; Jaeyong Lee

2010-01-01

325

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

326

Hysterisis Modeling by Inspection  

Microsoft Academic Search

By looking at the hysteresis loop of a core, its nonlinear magnetizing branch can be modeled by visual inspection. Three constants on the hysteresis loop reveal enough information about the core loss and non-linear inductance that power measurements and data-pairs can be avoided. An experimental hysteresis loop is taken from a CT and its model put together by visual inspection.

Fabian M. Uriarte; I. NOMENCLATURE

2006-01-01

327

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

328

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 GovernorÃÂs School for Science and Technology)

2007-07-16

329

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

330

Validation of simulation models  

Microsoft Academic Search

This is a tutorial paper on validation of simulation models. Included in this tutorial are what is meant by validation, the problem dependent characteristics of simulation model validation, descriptions of the various validation techniques and their use and a discussion on the statistics used in validation techniques (but not the detailed statistical tests themselves).

Robert G. Sargent

1979-01-01

331

Tsyganenko Geomagnetic Field Models  

NASA Astrophysics Data System (ADS)

The Tsyganenko models are semi-empirical best-fit representations for the magnetic field, based on a large number of satellite observations (IMP, HEOS, ISEE, POLAR, Geotail, GOES, etc). The models include the contributions from major external magnetospheric sources: ring current, magnetotail current system, magnetopause currents, and large-scale system of field-aligned currents.

Tsyganenko, Nikolai

2014-09-01

332

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.

333

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

334

PHRASE STRUCTURE COMPUTATIONAL MODEL  

E-print Network

PHRASE STRUCTURE IN A COMPUTATIONAL MODEL OF CHILD LANGUAGE ACQUISITION Helen Louise Gaylard a computational model of child language acquisition which acquires a recursive phrase-structure grammar, and thus triggers the acquisition of a phrase-structure grammar. The Lexical-Functional Grammar formalism

Yao, Xin

335

ACTUAL CAUSATION: ANALYSIS, MODELING &  

E-print Network

The Bastard Child They have sought a single causal relation that is fully objective, like causal structure his rock through the window) #12;Causal Models Modifiable Structural Equation Models Graphical and equations represent is the causal structure of this scenario The judgment that Suzy's throw caused

Fitelson, Branden

336

Creating Realistic BGP Models  

Microsoft Academic Search

Modeling the Internet infrastructure is a challenging en- deavor. Complex interactions between protocols, increas- ing traffic volumes and the irregular structure of the Inter- net lead to demanding requirements for the simulation de- veloper. These requirements include implementation detail, memory efficiency and scalability, among others. We intro- duce a simulation model of the Border Gateway Protocol that we call BGP++,

Xenofontas A. Dimitropoulos; George F. Riley

2003-01-01

337

Earth and ocean modeling  

NASA Technical Reports Server (NTRS)

A modular structured system of computer programs is presented utilizing earth and ocean dynamical data keyed to finitely defined parameters. The model is an assemblage of mathematical algorithms with an inherent capability of maturation with progressive improvements in observational data frequencies, accuracies and scopes. The Eom in its present state is a first-order approach to a geophysical model of the earth's dynamics.

Knezovich, F. M.

1976-01-01

338

Modelling University Governance  

ERIC Educational Resources Information Center

Twentieth century governance models used in public universities are subject to increasing doubt across the English-speaking world. Governments question if public universities are being efficiently governed; if their boards of trustees are adequately fulfilling their trust obligations towards multiple stakeholders; and if collegial models of…

Trakman, Leon

2008-01-01

339

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...

340

Prototype Thermoballistic Model  

NASA Astrophysics Data System (ADS)

The probabilistic approach to carrier transport is presented. Within this approach, a prototype thermoballistic model is developed. It incorporates as the constitutive element of the thermoballistic concept the ballistic configurations, which arise from a random partitioning of the length of a semiconducting sample into ballistic transport intervals. The prototype model allows various examples of current interest to be treated explicitly.

Lipperheide, Reinhard; Wille, Uwe

341

THE AQUATOX MODEL  

EPA Science Inventory

This lecture will present AQUATOX, an aquatic ecosystem simulation model developed by Dr. Dick Park and supported by the U.S. EPA. The AQUATOX model predicts the fate of various pollutants, such as nutrients and organic chemicals, and their effects on the ecosystem, including fi...

342

Flocculation modelling: a review  

Microsoft Academic Search

The modelling of the flocculation process is reviewed. Recent developments in this area are discussed with reference to the classical analytical expression of Smoluchowski defining collision frequency and originally published in 1917. The constraints imposed by six principal assumptions made by Smoluchowski are considered individually, with the key models that have been developed to address specific limitations discussed in detail.

D. N. Thomas; S. J. Judd; N. Fawcett

1999-01-01

343

Submarine Dynamic Modeling  

Microsoft Academic Search

This paper discusses the development of a dynamic model for a torpedo shaped sub- marine. Expressions for hydrostatic, added mass, hydrodynamic, control surface and pro- peller forces and moments are derived from first principles. Experimental data obtained from flume tests of the submarine are inserted into the model in order to provide computer simulations of the open loop behavior of

Peter Ridley; Julien Fontan; Peter Corke

344

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

345

Model Minority Stereotype Reconsidered.  

ERIC Educational Resources Information Center

This paper explores the origin and historical background of the "model minority" stereotype. It includes evidence illustrating problems resulting from the artificial grouping of Asian Americans as one ethnic group and the stereotype's influence on young Asian Americans. In the 1960s, the U.S. media began to portray the model minority through…

Kobayashi, Futoshi

346

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

347

Dynamic accelerator modeling  

SciTech Connect

Object-Oriented Programming has been used extensively to model the LBL Advanced Light Source 1.5 GeV electron storage ring. This paper is on the present status of the class library construction with emphasis on a dynamic modeling.

Nishimura, Hiroshi

1993-05-01

348

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...

349

Sound mobility models  

Microsoft Academic Search

Simulation has become an indispensable tool in the construction and evaluation of mobile systems. By using mobility models that describe constituent movement, one can explore large systems, producing repeatable results for comparison between alternatives. Unfortunately, the vast majority of mobility models---including all those in which nodal speed and distance or destination are chosen independently---suffer from decay; average speed decreases until

Jungkeun Yoon; Mingyan Liu; Brian Noble

2003-01-01

350

Estimation of model quality  

Microsoft Academic Search

This paper provides an introduction to recent work on the problem of quantifying errors in the estimation of models for dynamic systems. This is a very large field. We therefore concentrate on approaches that have been motivated by the need for reliable models for control system design. This will involve a discussion of efforts that go under the titles of

Brett Ninness; Graham C. Goodwin

1995-01-01

351

[Modelling of intrauterine hypoxia].  

PubMed

An experimental model of chronic intrauterine hypoxia is proposed. This model reflects the most typical posthypoxic impairments for the above pathology: intrauterine growth retardation, alterations in the placental parameters, posterity death in the neonatal period, physical retardation, postnatal disorders in the CNS functions. PMID:16408664

Spasov, A A; Tregubova, I A; Kosolapov, V A

2005-01-01

352

Participatory Evolving Fuzzy Modeling  

Microsoft Academic Search

This paper introduces an approach to develop evolving fuzzy rule-based models based on the idea of participatory learning. Participatory learning is a means to learn and revise beliefs based on what is already known or believed. Participatory learning naturally induces unsupervised dynamic fuzzy clustering algorithms and provides an effective alternative construct evolving functional fuzzy models and adaptive fuzzy systems. Evolving

E. Lima; F. Gomide; R. Ballini

2006-01-01

353

Logistic Model Trees  

Microsoft Academic Search

Tree induction methods and linear models are popular techniques for supervised learning tasks, both for the prediction of nominal classes and numeric values. For predicting numeric quantities, there has been work on combining these two schemes into ‘model trees’, i.e. trees that contain linear regression functions at the leaves. In this paper, we present an algorithm that adapts this idea

Niels Landwehr; Mark Hall; Eibe Frank

2005-01-01

354

Logistic Model Trees  

Microsoft Academic Search

Tree induction methods and linear models are popular techniques for supervised learning tasks, both for the prediction of nominal classes and numeric values. For predicting numeric quantities, there has been work on combining these two schemes into 'model trees', i.e. trees that contain linear regression functions at the leaves. In this paper, we present an algorithm that adapts this idea

Niels Landwehr; Mark Hall; Eibe Frank

2003-01-01

355

The Merchandising Mathematician Model  

Microsoft Academic Search

A simple model of a buying-selling cycle is proposed. The model comprises two moves: a rational buying and a random selling. The notion of a profit intensity is introduced. Supply and demand curves and geometrical interpretation are discussed in this context.

E. W. Piotrowski; J. Sladkowski

2001-01-01

356

Prewhirl Jet Model  

NASA Technical Reports Server (NTRS)

Simple accurate model of centrifugal or rocket engine pumps provides information necessary to design inducer backflow deflector, backflow eliminator and prewhirl jet in jet mixing zones. Jet design based on this model shows improvement in inducer suction performance and reduced cavitation damage.

Meng, S. Y.; Jensen, M.; Jackson, E. D.

1985-01-01

357

Editor's Corner: Model Biology  

NSDL National Science Digital Library

Models are at the core of the scientific enterprise. They help us make predictions, understand complex systems, generate new ideas, and visualize both the very large and the very small. The generation of models is the creative engine that drives scientifi

Metz, Steve

2011-02-01

358

Unitary Response Regression Models  

ERIC Educational Resources Information Center

The dependent variable in a regular linear regression is a numerical variable, and in a logistic regression it is a binary or categorical variable. In these models the dependent variable has varying values. However, there are problems yielding an identity output of a constant value which can also be modelled in a linear or logistic regression with…

Lipovetsky, S.

2007-01-01

359

Model for Contingency Contracting.  

ERIC Educational Resources Information Center

The Department of Human Development at Prince George's Community College has developed a contingency contracting model for the department's counseling and student services which presents planning and evaluation as interrelated parts of the same process of self-imposed accountability. The implementation of the model consisted of: (1) planning…

Prince George's Community Coll., Largo, MD. Dept. of Human Development.

360

Modeling Antibody Diversity.  

ERIC Educational Resources Information Center

Understanding antibody structure and function is difficult for many students. The rearrangement of constant and variable regions during antibody differentiation can be effectively simulated using a paper model. Describes a hands-on laboratory exercise which allows students to model antibody diversity using readily available resources. (PVD)

Baker, William P.; Moore, Cathy Ronstadt

1998-01-01

361

Lessons from Leading Models  

ERIC Educational Resources Information Center

Quint reports on a synthesis evaluation of three widely used high school reform models--Talent Development, First Things First, and career academies. She highlights approaches within each model that helped high schools restructure themselves in ways that affected student outcomes, particularly for struggling 9th graders and students from…

Quint, Janet

2008-01-01

362

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

363

Models of Word Recognition.  

ERIC Educational Resources Information Center

Hypotheses about the processes involved in word recognition are reviewed and assessed through four experiments. Overall results were compatible with criterion bias models. A version of this model attributes the advantage of words (over pseudowords and nonwords) to interfacilitation among single letter and lexical units in memory. (Author/RD)

Adams, Marilyn Jager

1979-01-01

364

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

365

Correlated Drainage Model  

E-print Network

In this article we present an example of a random oriented tree model on d-dimensional lattice, that is a forest in d=3 with positive probability. This is in contrast with the other random tree models in the literature which are a forest only when d strictly greater than 3.

Athreya, Siva

2009-01-01

366

Poisson Distribution Model  

NSDL National Science Digital Library

The Poisson Distribution Model shows how to use the Apache Commons Math library (included in EJS) to generate random numbers that follow the Poisson distribution. A histogram of the numbers is displayed. This simple teaching example illustrates the use of the Histogram view element and how to speed up a simulation by running the model several time before updating the view.

Franciscouembre

2013-02-13

367

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.

368

Interharmonics: Theory and Modeling  

Microsoft Academic Search

Some of the most remarkable issues related to interharmonic theory and modeling are presented. Starting from the basic definitions and concepts, attention is first devoted to interharmonic sources. Then, the interharmonic assessment is considered with particular attention to the problem of the frequency resolution and of the computational burden associated with the analysis of periodic steady-state waveforms. Finally, modeling of

A. Testa; M. F. Akram; R. Burch; G. Carpinelli; G. Chang; V. Dinavahi; C. Hatziadoniu; W. M. Grady; E. Gunther; M. Halpin; P. Lehn; Y. Liu; R. Langella; M. Lowenstein; A. Medina; T. Ortmeyer; S. Ranade; P. Ribeiro; N. Watson; J. Wikston; W. Xu

2007-01-01

369

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

370

Kepler Paper Model  

NSDL National Science Digital Library

In this activity, learners build a paper model of the spacecraft and photometer (telescope) used during NASA's Kepler Mission. This resource includes files for the model, which can be printed out on heavy stock paper, and instructions for assembling the various parts.

Nasa

2005-01-01

371

The Rasch Testlet Model  

ERIC Educational Resources Information Center

The Rasch testlet model for both dichotomous and polytomous items in testlet-based tests is proposed. It can be viewed as a special case of the multidimensional random coefficients multinomial logit model (MRCMLM). Therefore, the estimation procedures for the MRCMLM can be directly applied. Simulations were conducted to examine parameter recovery…

Wang, Wen-Chung; Wilson, Mark

2005-01-01

372

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

373

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

374

Modeling Distortionary Taxation  

Microsoft Academic Search

There has been a lot of discussion recently regarding the macroeconomic consequences of a distortionary taxation system. However the way this distortionary taxation scheme or instrument is modeled in macroeconomic analysis, as well as the ability of these models to capture the effects implied by this distortionary taxation system, is subject to criticism. This work provide a formal analysis in

Chronis Panagiotis

2009-01-01

375

Models of technology diffusion  

Microsoft Academic Search

The literature on new technology diffusion is vast, and it spills over many conventional disciplinary boundaries. This paper surveys the literature by focusing on alternative explanations of the dominant stylized fact: that the usage of new technologies over time typically follows an S-curve. The most commonly found model which is used to account for this model is the so-called epidemic

P. A. Geroski

2000-01-01

376

Anticipatory model of cavitation  

NASA Astrophysics Data System (ADS)

The Anticipatory System (AS) formalism developed by Robert Rosen provides some insight into the problem of embedding intelligent behavior in machines. AS emulates the anticipatory behavior of biological systems. AS bases its behavior on its expectations about the near future and those expectations are modified as the system gains experience. The expectation is based on an internal model that is drawn from an appeal to physical reality. To be adaptive, the model must be able to update itself. To be practical, the model must run faster than real-time. The need for a physical model and the requirement that the model execute at extreme speeds, has held back the application of AS to practical problems. Two recent advances make it possible to consider the use of AS for practical intelligent sensors. First, advances in transducer technology make it possible to obtain previously unavailable data from which a model can be derived. For example, acoustic emissions (AE) can be fed into a Bayesian system identifier that enables the separation of a weak characterizing signal, such as the signature of pump cavitation precursors, from a strong masking signal, such as a pump vibration feature. The second advance is the development of extremely fast, but inexpensive, digital signal processing hardware on which it is possible to run an adaptive Bayesian-derived model faster than real-time. This paper reports the investigation of an AS using a model of cavitation based on hydrodynamic principles and Bayesian analysis of data from high-performance AE sensors.

Kercel, Stephen W.; Allgood, Glenn O.; Dress, William B.; Hylton, James O.

1999-03-01

377

COMMUTER EXPOSURE MODELING METHODOLOGIES  

EPA Science Inventory

Two methodologies for modeling commuter exposures are proposed: computer-oriented approach and a manual approach. Both modeling methodologies require that major commuter routes, or pathways, be identified and that the traffic on the remainder of the roadway network be treated as ...

378

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

379

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...

380

Conformal superspace ?-models  

NASA Astrophysics Data System (ADS)

We review recent developments in the context of two-dimensional conformally invariant ?-models. These quantum field theories play a prominent role in the covariant superstring quantization in flux backgrounds and in the analysis of disordered systems. We present supergroup WZW models as primary examples of logarithmic conformal field theories, whose structure is almost entirely determined by the underlying supergeometry. In particular, we discuss the harmonic analysis on supergroups and supercosets and point out the subtleties of Lie superalgebra representation theory that are responsible for the emergence of logarithmic representations. Furthermore, special types of marginal deformations of supergroup WZW models are studied which only exist if the Killing form is vanishing. We show how exact expressions for anomalous dimensions of boundary fields can be derived using quasi-abelian perturbation theory. Finally, the knowledge of the exact spectrum is used to motivate a duality between the OSP(4|2) symmetric Gross-Neveu model and the S supersphere ?-model.

Mitev, Vladimir; Quella, Thomas; Schomerus, Volker

2011-09-01

381

Building a Model Astrolabe  

E-print Network

This paper presents a hands-on introduction to the medieval astrolabe, based around a working model which can be constructed from photocopies of the supplied figures. As well as describing how to assemble the model, I also provide a brief explanation of how each of its various parts might be used. The printed version of this paper includes only the parts needed to build a single model prepared for use at latitudes around 52{\\deg}N, but an accompanying electronic file archive includes equivalent images which can be used to build models prepared for use at any other latitude. The vector graphics scripts used to generate the models are also available for download, allowing customised astrolabes to be made.

Ford, Dominic

2012-01-01

382

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

2014-01-23

383

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

384

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

385

Radioactive Decay Events Model  

NSDL National Science Digital Library

The EJS Radioactive Decay Events Model simulates the decay of a radioactive sample using discrete random events. It displays the number of events (radioactive decays) as a function of time in a given time interval. You can change the initial number of nuclei, the decay constant and the time interval for the event distribution. The Radioactive Decay Events 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_ms_explicit_RadioactiveDecayEvents.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

2009-01-23

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

Varicella infection modeling.  

SciTech Connect

Infectious diseases can spread rapidly through healthcare facilities, resulting in widespread illness among vulnerable patients. Computational models of disease spread are useful for evaluating mitigation strategies under different scenarios. This report describes two infectious disease models built for the US Department of Veteran Affairs (VA) motivated by a Varicella outbreak in a VA facility. The first model simulates disease spread within a notional contact network representing staff and patients. Several interventions, along with initial infection counts and intervention delay, were evaluated for effectiveness at preventing disease spread. The second model adds staff categories, location, scheduling, and variable contact rates to improve resolution. This model achieved more accurate infection counts and enabled a more rigorous evaluation of comparative effectiveness of interventions.

Jones, Katherine A.; Finley, Patrick D.; Moore, Thomas W.; Nozick, Linda Karen; Martin, Nathaniel; Bandlow, Alisa; Detry, Richard Joseph; Evans, Leland B.; Berger, Taylor Eugen

2013-09-01

388

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

389

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

390

Interactive Model Problem Set  

NSDL National Science Digital Library

The problem set asks students to complete and discuss interactive, policy-relevant models from two case studies of models and policy that have been previously discussed in class: fisheries and chemicals. The first question asks the students to play the online Fishbanks game, which uses a model interface to illustrate management strategies for fisheries. The students are then asked to think about how the model might be used in decision-making contexts. The second question asks students to consider the case of a chemical under review in the context of the Stockholm Convention on Persistent Organic Pollutants, and to assess its overall persistence and long-range transport using an Excel-based modeling tool.

Selin, Noelle

391

Linear models: permutation methods  

USGS Publications Warehouse

Permutation tests (see Permutation Based Inference) for the linear model have applications in behavioral studies when traditional parametric assumptions about the error term in a linear model are not tenable. Improved validity of Type I error rates can be achieved with properly constructed permutation tests. Perhaps more importantly, increased statistical power, improved robustness to effects of outliers, and detection of alternative distributional differences can be achieved by coupling permutation inference with alternative linear model estimators. For example, it is well-known that estimates of the mean in linear model are extremely sensitive to even a single outlying value of the dependent variable compared to estimates of the median [7, 19]. Traditionally, linear modeling focused on estimating changes in the center of distributions (means or medians). However, quantile regression allows distributional changes to be estimated in all or any selected part of a distribution or responses, providing a more complete statistical picture that has relevance to many biological questions [6]...

Cade, B.S.

2005-01-01

392

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

393

Rainfall erosion model  

NASA Astrophysics Data System (ADS)

A model describing rainfall erosion over the course of a long time period is proposed. The model includes: (1) a new equation of detachment of soil particles by water flows based on the Mirtskhulava equation; (2) a new equation for the transport capacity of the flow based on a modified Bagnold equation, which is used in the AGNPS model; (3) modified SCS runoff equation; (4) probability distributions for rainfall. The proposed equations agree satisfactorily with the data of on-site observations of the Moldova and Nizhnedevitsk water-balance stations. The Monte Carlo method is used for numerical modeling of random variables. The results of modeling agree satisfactorily with empirical equations developed for conditions in Russia and the United States. The effect of climatic conditions on the dependence of longtime average annual soil loss on various factors is analyzed. Minimum information is used for assigning the initial data.

Sukhanovskii, Yu. P.

2010-09-01

394

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

395

Integrated Workforce Modeling System  

NASA Technical Reports Server (NTRS)

There are several computer-based systems, currently in various phases of development at KSC, which encompass some component, aspect, or function of workforce modeling. These systems may offer redundant capabilities and/or incompatible interfaces. A systems approach to workforce modeling is necessary in order to identify and better address user requirements. This research has consisted of two primary tasks. Task 1 provided an assessment of existing and proposed KSC workforce modeling systems for their functionality and applicability to the workforce planning function. Task 2 resulted in the development of a proof-of-concept design for a systems approach to workforce modeling. The model incorporates critical aspects of workforce planning, including hires, attrition, and employee development.

Moynihan, Gary P.

2000-01-01

396

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

397

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

398

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

399

Simulation model verification and validation  

Microsoft Academic Search

Verification and validation of simulation models are discussed. The different approaches to deciding model validity are described; how model verification and validation relate to the model development process is specified; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are discussed; ways to document results are given; and a recommended validation procedure is presented

Robert G. Sargent

1991-01-01

400

Verifying and validating simulation models  

Microsoft Academic Search

This paper discusses verification and validation of simulation models. The different approaches to deciding model validity are presented, how model verification and validation relate to the model development process are discussed; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are described, ways to document results are given; and a recommended procedureispresented.

Robert G. Sargent

1996-01-01

401

Verifying and validating simulation models  

Microsoft Academic Search

This paper discusses verification and validation of simulation models. The different approaches to deciding model validity am presented; how model verification and validation relate to the model development process are discussed; various validation techniques are defined, conceptual model validity, model verification, operational validity, and data validity are described; ways to document results are given; and a recommended procedure is presented.

Robert G. Sargent

1996-01-01

402

Simulation model verification and validation  

Microsoft Academic Search

This paper discusses verification and validation of simulation models. The different approaches to deciding model validity are described; how model verification and validation relate to the model development process is specified; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are discussed; ways to document results are given; and a recommended validation procedure is

Robert G. Sargent

1991-01-01

403

Virtual prototyping with Data Modeling  

Microsoft Academic Search

We present an approach to convert slow running, high fidelity simulations into fast running models via analogy. These high order polynomial models use Data Modeling coupled with multivariate regression. Shown are models for individual data sets, field measured data, simulations like the Navy Experimental Dive Unit rebreather model, simulation driver equations for the Kinetic Impact Debris Distribution model, and a

Holger M. Jaenisch; James W. Handley; Kent H. White; James W. Watson; Carl T. Case; Claude G. Songy

2002-01-01

404

Multizone Airflow Model in Modelica  

Microsoft Academic Search

We present the implementation of a library of multi- zone airflow models in Modelica and a comparative model validation with CONTAM. Our models have a similar level of detail as the models in CONTAM and COMIS. The multizone airflow models allow model- ing the flow between rooms through doors, staircases or construction cracks. The flow can be caused by buoyancy

Michael Wetter

2006-01-01

405

Modeling cellobiose hydrolysis with integrated kinetic models  

Microsoft Academic Search

The enzyme cellobiase Novozym 188, which is used for improving hydrolysis of bagasse with cellulase, was characterized in\\u000a its commercial available form and integrated kinetic models were applied to the hydrolysis of cellobiose. The specific activity\\u000a of this enzyme was determined for pH values from 3.0–7.0, and temperatures from 40–75°C, with cellobiose at 2 g\\/L. Thermal\\u000a stability was measured at

Luiza P. V. Calsavara; Flávio F. De Moraes; Gisella M. Zanin

1999-01-01

406

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

407

PET Pharmacokinetic Modelling  

NASA Astrophysics Data System (ADS)

Positron Emission Tomography is a well-established technique that allows imaging and quantification of tissue properties in-vivo. The goal of pharmacokinetic modelling is to estimate physiological parameters, e.g. perfusion or receptor density from the measured time course of a radiotracer. After a brief overview of clinical application of PET, we summarize the fundamentals of modelling: distribution volume, Fick's principle of local balancing, extraction and perfusion, and how to calculate equilibrium data from measurements after bolus injection. Three fundamental models are considered: (i) the 1-tissue compartment model, e.g. for regional cerebral blood flow (rCBF) with the short-lived tracer [15O]water, (ii) the 2-tissue compartment model accounting for trapping (one exponential + constant), e.g. for glucose metabolism with [18F]FDG, (iii) the reversible 2-tissue compartment model (two exponentials), e.g. for receptor binding. Arterial blood sampling is required for classical PET modelling, but can often be avoided by comparing regions with specific binding with so called reference regions with negligible specific uptake, e.g. in receptor imaging. To estimate the model parameters, non-linear least square fits are the standard. Various linearizations have been proposed for rapid parameter estimation, e.g. on a pixel-by-pixel basis, for the prize of a bias. Such linear approaches exist for all three models; e.g. the PATLAK-plot for trapping substances like FDG, and the LOGAN-plot to obtain distribution volumes for reversibly binding tracers. The description of receptor modelling is dedicated to the approaches of the subsequent lecture (chapter) of Millet, who works in the tradition of Delforge with multiple-injection investigations.

Müller-Schauenburg, Wolfgang; Reimold, Matthias

408

Complexity regularized hydrological model selection  

NASA Astrophysics Data System (ADS)

Ill-posed hydrological model selection problems (that may be unstable or have non-unique solutions) are regularized with hydrological model complexity as the stabilizer. We propose and apply a notion of model complexity, based on Vapnik-Chervonenkis generalization theory, to complexity regularized hydrologic model selection. Better hydrologic models (better performance on future unseen data) on small sample sizes are identified using complexity regularized model selection than when using traditional model selection (without regularization) while both converge in performance for large samples (i.e. regularized model selection is 'consistent'). Case studies using SAC-SMA, SIXPAR and flexible model structures are used to 1) compute and compare model complexities of different model structures, 2) demonstrate the 'consistency' of complexity regularized model selection and 3) demonstrate that regularized model selection identifies the best model structure (out of a set of competing structures) on small sample sizes better than un-regularized model selection.

Arkesteijn, Liselot; Pande, Saket; Savenije, Hubert

2014-05-01

409

Multiscale modeling of chalcogenides  

NASA Astrophysics Data System (ADS)

Chalcogenide glasses exhibit unique properties applicable to a wide range of fields, including electrical and optical switching and the transmission of infrared radiation. In this thesis, we adopt a hierarchical multiscale modeling approach to investigate the fundamental physics of chalcogenide systems. Our multiscale modeling begins in Part I at the quantum mechanical level, where we use the highly accurate Moller-Plesset perturbation technique to derive interaction potentials for elemental and heterogeneous chalcogenide systems. The resulting potentials consist of two-, three-, and effective four-body terms. In Part II, we use these ab initio potentials in classical Monte Carlo simulations to investigate the structure of chalcogenide glasses. We discuss our simulation results in relation to the Phillips model of topological constraints, which predicts critical behavior in chalcogenide systems as a function of average coordination number. Finally, in Part III we address the issue of glass transition range behavior. After reviewing previous models of the glass transition, we derive a new model based on nonequilibrium statistical mechanics and an energy landscape formalism. The new model requires as input a description of inherent structure energies and the transition energies between these structures. To address this issue, we derive an eigenvector-following technique for mapping a multidimensional potential energy landscape. This technique is then extended for application to enthalpy landscapes. Our model will enable the first-ever calculation of glass transition behavior based on only ab initio physics.

Mauro, John C.

410

Biophysical models in hadrontherapy  

NASA Astrophysics Data System (ADS)

One major rationale for the application of ion beams in tumor therapy is their increased relative biological effectiveness RBE in the Bragg peak region For dose prescription the increased effectiveness has to be taken into account in treatment planning Hence the complex dependencies of RBE on the dose level biological endpoint position in the field etc require biophysical models which have to fulfill two important criteria simplicity and quantitative precision Simplicity means that the number of free parameters should be kept at a minimum Due to the lack of precise quantitative data at least at present this requirement is incompatible with approaches aiming at the molecular modeling of the whole chain of production processing and repair of biological damages Quantitative precision is required since steep gradients in the dose response curves are observed for most tumor and normal tissues thus even small uncertainties in the estimation of the biologically effective dose can transform into large uncertainties in the clinical outcome The paper will give a general introduction into the field followed by a brief description of a specific model the so called Local Effect Model LEM This model has been successfully applied within treatment planning in the GSI pilot project for carbon ion tumor therapy over almost 10 years now The model is based on the knowledge of charged particle track structure in combination with the response of the biological objects to conventional photon radiation The model will be critically discussed with respect to other

Scholz, M.; Elsaesser, T.

411

GIA Ice Models  

NASA Astrophysics Data System (ADS)

Defining the ice load in a way that avoids circularity is perhaps the most difficult aspect of GIA modeling. At any instant of past time the global land-supported ice load must honor the meltwater curve and the known edges of the ice, but within these constraints the ice mass can be swapped to a considerable extent between the various glacial systems and parts of those systems. In our models, ice thickness is controlled by the effective basal shear stress (EBSS). This parameter incorporates the sub-ice lithology (e.g., whether the ice rests on sediment of crystalline rock), the relative local snow accumulation rate, and the local basal shear strength (which presumably depends most strongly on sub-ice temperature). The effective basal shear stress can be fairly easily modified to construct an ice model. The ice model is evaluated by the geological reasonability of its changes in EBSS in space and time, and by how well it matches measured GIA data. The risk that an incorrect earth model can be forced to fit the GIA data by manipulating the ice model (the circularity mentioned above) can be minimized by evaluating the longest wavelength deformations (peripheral bulge behavior) before proceeding to the shorter wavelength deformations (local emergence variations). The poster will describe how we have proceeded in this fashion to develop a framework for interpreting GIA data in Norway. The poster will be augmented by computer software that compares emergence data to models at specific sites in Norway.

Kachuck, Samuel; Cathles, Larry; Amantov, Aleksey

2013-04-01

412

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

413

Combining thermal comfort models  

SciTech Connect

Two models commonly used in thermal comfort studies were combined to develop a two-dimensional computer model that estimates the resistance to dry and evaporative heat transfer for a clothing system from fabric resistance data, fabric thickness data, and information concerning the amount of body surface area covered by different fabric layers and the amount of air trapped between fabric layers. Five different clothing ensembles with different total thermal insulation and very different distributions of the insulation on the body were simulated with 16 sedentary subjects. This paper first evaluates total thermal insulation predictions from the Fanger steady-state model and then uses these data in the Gagge two-compartment (or two-node) model. The combined model uses the transient heat balance of each segment and the whole body. It estimates total insulation value and then uses this value to calculate transient temperature and wettedness. By application of the combined model, predictions of human responses to a wide range of thermal conditions are compared with the responses of human subjects as described in reports of laboratory experiments. Possible reasons for discrepancies between the observed data and predictions of the model are briefly discussed.

Yigit, A.

1999-07-01

414

Little Z' models  

NASA Astrophysics Data System (ADS)

We discuss the possibility that a Z' gauge boson, predicted by a large class of models in which the Higgs doublet is charged under U(1)', can have a reduced gauge coupling and can therefore be quite light, even below the 1 TeV scale, avoiding present experimental constraints. This generic possibility is discussed within the framework of the class of supersymmetric E6-inspired models as an example. Since the Z' can be light, we refer to such models as Little Z' models. One of the main motivations for such models is to reduce the fine-tuning due to the current experimental limits on the Z' mass. As we point out, such fine-tuning arises when the Higgs doublets are charged under the extra U(1)' gauge group leading to large additional D-terms in the Higgs potential. We show that reducing the value of the extra gauge coupling relaxes the experimental limits, leading to the possibility of low-mass Z' resonances, for example down to 200 GeV, which may yet appear in LHC searches. Although the source of tree-level fine-tuning due to the Z' mass is reduced, it typically does so at the expense of increasing the vacuum expectation value of the U(1)'-breaking standard model singlet field, reducing the fine-tuning to levels similar to that in the minimal supersymmetric standard model.

Belyaev, Alexander; King, Stephen F.; Svantesson, Patrik

2013-08-01

415

Turbulence Modeling Workshop  

NASA Technical Reports Server (NTRS)

Advances in turbulence modeling are needed in order to calculate high Reynolds number flows near the onset of separation and beyond. To this end, the participants in this workshop made the following recommendations. (1) A national/international database and standards for turbulence modeling assessment should be established. Existing experimental data sets should be reviewed and categorized. Advantage should be taken of other efforts already under-way, such as that of the European Research Community on Flow, Turbulence, and Combustion (ERCOFTAC) consortium. Carefully selected "unit" experiments will be needed, as well as advances in instrumentation, to fill the gaps in existing datasets. A high priority should be given to document existing turbulence model capabilities in a standard form, including numerical implementation issues such as grid quality and resolution. (2) NASA should support long-term research on Algebraic Stress Models and Reynolds Stress Models. The emphasis should be placed on improving the length-scale equation, since it is the least understood and is a key component of two-equation and higher models. Second priority should be given to the development of improved near-wall models. Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) would provide valuable guidance in developing and validating new Reynolds-averaged Navier-Stokes (RANS) models. Although not the focus of this workshop, DNS, LES, and hybrid methods currently represent viable approaches for analysis on a limited basis. Therefore, although computer limitations require the use of RANS methods for realistic configurations at high Reynolds number in the foreseeable future, a balanced effort in turbulence modeling development, validation, and implementation should include these approaches as well.

Rubinstein, R. (Editor); Rumsey, C. L. (Editor); Salas, M. D. (Editor); Thomas, J. L. (Editor); Bushnell, Dennis M. (Technical Monitor)

2001-01-01

416

Swing Ride Model  

NSDL National Science Digital Library

The Swing Ride Model simulates a type of ride that can be found at many carnivals and amusement parks. Riders are suspended from the ends of supports. These supports rotate about an axis that can be tilted with respect to the vertical. In this simulation the controls are lagged to prevent unrealistic changes to the physical system. The Swing Ride 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.

2012-01-15

417

Tetrade Spin Foam Model  

E-print Network

We propose a spin foam model of four-dimensional quantum gravity which is based on the integration of the tetrads in the path integral for the Palatini action of General Relativity. In the Euclidian gravity case we show that the model can be understood as a modification of the Barrett-Crane spin foam model. Fermionic matter can be coupled by using the path integral with sources for the tetrads and the spin connection, and the corresponding state sum is based on a spin foam where both the edges and the faces are colored independently with the irreducible representations of the spacetime rotations group.

A. Mikovic

2005-04-26

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

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.

2011-06-23

420

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

421

Modeling regional power transfers  

SciTech Connect

The Spot Market Network (SMN) model was used to estimate spot market transactions and prices between various North American Electric Reliability Council (NERC) regions for summer on-peak situations. A preliminary analysis of new or proposed additions to the transmission network was performed. The effects of alternative exempt wholesale generator (EWG) options on spot market transactions and the transmission system are also studied. This paper presents the SMN regional modelling approach and summarizes simulation results. Although the paper focuses on a regional network representation, a discussion of how the SMN model was used to represent a detailed utility-level network is also presented.

Kavicky, J.A.; Veselka, T.D.

1994-03-01

422

Modeling dihadron fragmentation functions  

E-print Network

We present a model for dihadron fragmentation functions, describing the fragmentation of a quark into two unpolarized hadrons. We tune the parameters of our model to the output of the PYTHIA event generator for two-hadron semi-inclusive production in deep inelastic scattering at HERMES. Once the parameters of the model are fixed, we make predictions for other unknown fragmentation functions and for a single-spin asymmetry in the azimuthal distribution of pi+ pi- pairs in semi-inclusive deep inelastic scattering on a transversely polarized target at HERMES and COMPASS. Such asymmetry could be used to measure the quark transversity distribution function.

Alessandro Bacchetta; Marco Radici

2006-08-03

423

Modeling Compressed Turbulence  

SciTech Connect

From ICE to ICF, the effect of mean compression or expansion is important for predicting the state of the turbulence. When developing combustion models, we would like to know the mix state of the reacting species. This involves density and concentration fluctuations. To date, research has focused on the effect of compression on the turbulent kinetic energy. The current work provides constraints to help development and calibration for models of species mixing effects in compressed turbulence. The Cambon, et al., re-scaling has been extended to buoyancy driven turbulence, including the fluctuating density, concentration, and temperature equations. The new scalings give us helpful constraints for developing and validating RANS turbulence models.

Israel, Daniel M. [Los Alamos National Laboratory

2012-07-13

424

Pendulum Energy Model  

NSDL National Science Digital Library

The EJS Pendulum Energy Model shows a pendulum and associated energy bar charts. Users can change the initial starting point of the pendulum. The Pendulum Energy 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_middle_school_teacher_PendulumEnergy.jar file will run the program if Java is installed. The user can modify this simulation if EJS is installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item.

Christian, Wolfgang; Belloni, Mario; Cox, Anne

2009-06-22

425

Newton's Mountain JS Model  

NSDL National Science Digital Library

The EJS Newton's Mountain JS model illustrates the motion of a projectile launched from the top of a VERY tall mountain on Earth. The diagram shown in the simulation is taken from Newton's A Treatise on the System of the World, which he wrote after the Principia, but the basic idea is found in the Principia itself. Newton concluded that a projectile launched horizontally with sufficient speed would orbit Earth rather than crashing to Earth's surface. Thus the motion of a projectile fired on Earth was not qualitatively different from that of the moon orbiting Earth. EJS Newton's Mountain JS Model was created using the Easy Java Simulations (EJS) modeling tool.

Timberlake, Todd; Belloni, Mario

2014-01-05

426

Eigenstate Superposition Model  

NSDL National Science Digital Library

The Eigenstate Superposition model illustrates the fundamental building blocks of one-dimensional quantum mechanics, the energy eigenfunctions  ψn(x) and energy eigenvalues En. The user enters the expansion coefficients into a table and the simulation uses the superposition principle to construct and display a time-dependent wave function using either infinite square well (ISW) or simple harmonic oscillator (SHO) eigenfunctions. The Eigenstate Superposition 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_Superposition.jar file will run the program if Java is installed.

Christian, Wolfgang

2008-08-31

427

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

428

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

429

Faces of matrix models  

NASA Astrophysics Data System (ADS)

Partition functions of eigenvalue matrix models possess a number of very different descriptions: as matrix integrals, as solutions to linear and nonlinear equations, as ?-functions of integrable hierarchies and as special-geometry prepotentials, as result of the action of W-operators and of various recursions on elementary input data, as gluing of certain elementary building blocks. All this explains the central role of such matrix models in modern mathematical physics: they provide the basic "special functions" to express the answers and relations between them, and they serve as a dream model of what one should try to achieve in any other field.

Morozov, A.

2012-08-01

430

Classical Helium Model  

NSDL National Science Digital Library

The EJS Classical Helium Model is an example of a three-body problem that is similar to the gravitational three-body problem of a heavy sun and two light planets. The important difference is that the helium atom's two electrons repel one another, unlike the planetary case where the intraplanetary interaction is attractive. The EJS Classical Helium 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_orbits_ClassicalHelium.jar file will run the program if Java is installed.

Christian, Wolfgang

2009-03-14

431

Radon diffusion modelling.  

PubMed

A mathematical model has been developed that examines the ingress of radon into houses, through a vertical crack in an otherwise impervious concrete floor. Initially, the model considered the diffusive flow of radon from its soil source and this simulation has highlighted the dependency of the flux of radon into the house on the magnitude of various parameters, such as the diffusion coefficient of radon in soil. A preliminary investigation of the modelling of pressure-driven flow into a building is presented, and the potential of this type of analysis is discussed. PMID:4081719

Wilkinson, P; Dimbylow, P J

1985-10-01

432

Animal Model of Dermatophytosis  

PubMed Central

Dermatophytosis is superficial fungal infection caused by dermatophytes that invade the keratinized tissue of humans and animals. Lesions from dermatophytosis exhibit an inflammatory reaction induced to eliminate the invading fungi by using the host's normal immune function. Many scientists have attempted to establish an experimental animal model to elucidate the pathogenesis of human dermatophytosis and evaluate drug efficacy. However, current animal models have several issues. In the present paper, we surveyed reports about the methodology of the dermatophytosis animal model for tinea corporis, tinea pedis, and tinea unguium and discussed future prospects. PMID:22619489

Shimamura, Tsuyoshi; Kubota, Nobuo; Shibuya, Kazutoshi

2012-01-01

433

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

434

Freeze Prediction Model  

NASA Technical Reports Server (NTRS)

Measurements of wind speed, net irradiation, and of air, soil, and dew point temperatures in an orchard at the Rock Springs Agricultural Research Center, as well as topographical and climatological data and a description of the major apple growing regions of Pennsylvania were supplied to the University of Florida for use in running the P-model, freeze prediction program. Results show that the P-model appears to have considerable applicability to conditions in Pennsylvania. Even though modifications may have to be made for use in the fruit growing regions, there are advantages for fruit growers with the model in its present form.

Morrow, C. T. (principal investigator)

1981-01-01

435

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

436

Modeling Hofmeister Effects  

PubMed Central

A two dimensional model of water, so-called Mercedes-Benz model, was used to study effects of the size of hydrophobic solute on the insertion thermodynamics in electrolyte solutions. The model was examined by the constant pressure Monte Carlo computer simulation. The results were compared with the experimental data for noble gasses and methane in water and electrolyte solution. The influence of different ions at infinite dilution on the free energy of transfer was explored. Qualitative agreement with the experimental results was obtained. The mechanism of Hofmeister effects was proposed. PMID:20161468

Hribar-Lee, Barbara; Vlachy, Vojko; Dill, Ken A.

2009-01-01

437

Computer Modeling Of Atomization  

NASA Technical Reports Server (NTRS)

Improved mathematical models based on fundamental principles of conservation of mass, energy, and momentum developed for use in computer simulation of atomization of jets of liquid fuel in rocket engines. Models also used to study atomization in terrestrial applications; prove especially useful in designing improved industrial sprays - humidifier water sprays, chemical process sprays, and sprays of molten metal. Because present improved mathematical models based on first principles, they are minimally dependent on empirical correlations and better able to represent hot-flow conditions that prevail in rocket engines and are too severe to be accessible for detailed experimentation.

Giridharan, M.; Ibrahim, E.; Przekwas, A.; Cheuch, S.; Krishnan, A.; Yang, H.; Lee, J.

1994-01-01

438

Beyond Standard Model Physics  

E-print Network

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.

L. Bellantoni

2009-11-12

439

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

440

Low dimensional sigma models  

SciTech Connect

We discuss classical solutions of U(N) sigma models in two dimensions. We show how from these solutions we can construct solutions of the U(N) sigma model with the Wess--Zumino term (with an arbitrary coefficient). We discuss briefly various properties of these solutions. Next we consider the O(3) sigma model in 2 + 1 dimensions and describe the preliminary results of some numerical work in which we studied the time evolution of some of the previously discussed two dimensional structures (instantons and anti-instantons) under suitable assumptions about their initial values. 9 refs., 6 figs.

Zakrzewski, W.J.

1988-01-01

441

Nitriding modelling in nanoscale  

NASA Astrophysics Data System (ADS)

Modelling on Plasma and gas nitriding of austenitic and low alloy steels have strong influence of interfacial - nanoescale phenomena. Gamma prime and epsilon nitrogen-iron phases evolution during the nitriding process wasn't found explicitly simulated on literature. On present work we simulated nitrind process on low alloy steels - with their precipitation phenomena and nitrides moving interfaces - using diffusional models plus cellular automata. Surface effects and heterogeneities and local transition phenomena considered on our models show that some experimental results considered "errors" on literature are predicted by our simulations. In present work parameters like diffusion coefficient and surface conditions and gradient of nitrogen concentrations between different phases was measured.

Politano, R.

2013-02-01

442

Modeling Hofmeister Effects.  

PubMed

A two dimensional model of water, so-called Mercedes-Benz model, was used to study effects of the size of hydrophobic solute on the insertion thermodynamics in electrolyte solutions. The model was examined by the constant pressure Monte Carlo computer simulation. The results were compared with the experimental data for noble gasses and methane in water and electrolyte solution. The influence of different ions at infinite dilution on the free energy of transfer was explored. Qualitative agreement with the experimental results was obtained. The mechanism of Hofmeister effects was proposed. PMID:20161468

Hribar-Lee, Barbara; Vlachy, Vojko; Dill, Ken A

2009-03-11

443

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

444

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

445

Model Transformations for Migrating Legacy Models: An Industrial Case Study  

E-print Network

, there is a growing demand to migrate these GM-specific, legacy models to AUTOSAR models. Given that AUTOSAR definesModel Transformations for Migrating Legacy Models: An Industrial Case Study Gehan M. K. Selim1 model transformations to address the challenges in migrating GM legacy mod- els to their AUTOSAR

Cordy, James R.

446

Bayesian Feature and Model Selection for Gaussian Mixture Models  

E-print Network

Bayesian Feature and Model Selection for Gaussian Mixture Models Constantinos Constantinopoulos for mixture model training that simultaneously treats the feature selection and the model selection problem. The method is based on the integration of a mixture model formulation that takes into account the saliency

Likas, Aristidis

447

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

448

Motivation The Motif Model Conclusion A Model of Musical Motifs  

E-print Network

Motivation The Motif Model Conclusion A Model of Musical Motifs Torsten Anders MCM 2007 18 May 2007 #12;Motivation The Motif Model Conclusion Outline 1 Motivation 2 The Motif Model 3 Conclusion #12;Motivation The Motif Model Conclusion Introduction: Music Constraint Programming Research field Computational

Miranda, Eduardo Reck

449

Modeling the Remaining Flexibility of Partially Fixed Statistical Shape Models  

E-print Network

Modeling the Remaining Flexibility of Partially Fixed Statistical Shape Models Thomas Albrecht reconstruction but also the remaining flexibility within the model and the reliability of the reconstruction. We present a method to model the remaining flexibility when some part of a statistical shape model is fixed

Vetter, Thomas

450

Two decades of CGE modelling lessons from models for Egypt  

Microsoft Academic Search

Egypt's exceptional experience of two decades of CGE modelling is used to derive lessons for comparable analysis for other countries, give important issues for CGE modelling in general and give future modellers a guide to build on the older modelling experience. It can be derived from the CGE studies of the Egyptian economy that the model closure and the parameters

Mark Thissen

1998-01-01

451

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

452

Ontology Modeling and Object Modeling in Software Engineering  

Microsoft Academic Search

A data model is a plan for building a database and is comparable to an architect's building plans. There are two major methodologies used to create a data model: the Entity- Relationship (ER) approach and the Object Model. This paper will be discussed only the object model approach. The goal of the data model is to certify that all data

Waralak V. Siricharoen

2009-01-01

453

Mutation-based Model Synthesis in Model Driven Engineering  

Microsoft Academic Search

With the increasing use of models for software development and the emergence of model-driven engineering, it has become important to build accurate and precise models that present certain characteristics. Model transformation testing is a domain that requires generating a large number of models that satisfy coverage properties (cover the code of the transformation or the structure of the metamodel). However,

Sagar Sen; Benoit Baudry

2006-01-01

454

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

455

Parallelized Model Predictive Control  

E-print Network

Model predictive control (MPC) has been used in many industrial applications because of its ability to produce optimal performance while accommodating constraints. However, its application on plants with fast time constants ...

Soudbakhsh, Damoon

456

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...

457

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

458

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

459

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

460

Factorial Hidden Markov Models  

E-print Network

We present a framework for learning in hidden Markov models with distributed state representations. Within this framework, we derive a learning algorithm based on the Expectation--Maximization (EM) procedure for maximum ...

Ghahramani, Zoubin

1996-02-09

461

Computationally modeling interpersonal trust  

E-print Network

We present a computational model capable of predicting—above human accuracy—the degree of trust a person has toward their novel partner by observing the trust-related nonverbal cues expressed in their social interaction. ...

Lee, Jin Joo

462

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.

463

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

464

Fraction Model III  

NSDL National Science Digital Library

An interactive tool to represent a fraction circle, rectangle, or set model with numerators and denominators ranging from 1 to 100. The decimal and percent equivalents of the created fraction are also displayed.

Mathematics, Illuminations N.

2009-03-11

465

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

466

UPDATING APPLIED DIFFUSION MODELS  

EPA Science Inventory

Most diffusion models currently used in air quality applications are substantially out of date with understanding of turbulence and diffusion in the planetary boundary layer. Under a Cooperative Agreement with the Environmental Protection Agency, the American Meteorological Socie...

467

Using the Partnership Model  

ERIC Educational Resources Information Center

Demonstrates how the Partnership Model can be utilized in the real world by showing how it served as a guide during the production of a film on female menopause for the College of Human Medicine. (MH)

Wilks, Bob

1977-01-01

468

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

469

Wire and column modeling  

E-print Network

The goal of this thesis is to introduce new methods to create intricate perforated shapes in a computing environment. Modeling shapes with a large number of holes and handles, while requiring minimal human interaction, is an unsolved research...

Mandal, Esan

2004-09-30

470

Introduction Statistical Models  

E-print Network

model represents air pollution from line sources based on Gaussian diffusion. One might simply make of Statistics; University of California, Berkeley and Department of Biostatistics; Harvard School of Public

Paciorek, Chris

471

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

472

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

473

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

474

Status of Phenomenological Modeling.  

National Technical Information Service (NTIS)

Mathematical models serve two primary functions, to provide the means for estimating the effects of exposures which fall outside the range which can be investigated directly, and to form a framework for organizing observations so that the patterns and eve...

L. A. Braby

1986-01-01

475

Performance Models Implementation  

E-print Network

Background Algorithms Performance Models Implementation Summary Avoiding Communication in Sparse of computation Communication avoiding: Trade o communication with computation. Arbitrary speedups possible International Parallel and Distributed Processing Symposium, 2008 Mohiyuddin et al. Avoiding Comm. in Sparse

Yelick, Katherine

476

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

Allred, Benjamin; Neilson, Ew; Campbell, Todd

2010-11-01

477

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

478

Modeled as + n + n  

NASA Astrophysics Data System (ADS)

A three-body calculation for the and hypernuclei has been undertaken. The respective cores are . The interactions in the system, modeled as , are reasonably well known. For example, the p n interaction is well determined by the p n scattering data, the - p interaction can be fitted to the binding energy. The - n interaction can be fitted to ?- n scattering data. For the 4He- n system the s-wave can be modeled alternatively as a repulsive potential or as an attractive potential with a forbidden bound state. We explore these alternatives in 6He, because the interaction comes into play in modeling as well as in our + n + n model of , where the valence neutrons are Pauli blocked from the s-shell of the core nucleus.

Gibson, B. F.; Afnan, I. R.

2014-08-01

479

Base Flow Model Validation  

NASA Technical Reports Server (NTRS)

A method was developed of obtaining propulsive base flow data in both hot and cold jet environments, at Mach numbers and altitude of relevance to NASA launcher designs. The base flow data was used to perform computational fluid dynamics (CFD) turbulence model assessments of base flow predictive capabilities in order to provide increased confidence in base thermal and pressure load predictions obtained from computational modeling efforts. Predictive CFD analyses were used in the design of the experiments, available propulsive models were used to reduce program costs and increase success, and a wind tunnel facility was used. The data obtained allowed assessment of CFD/turbulence models in a complex flow environment, working within a building-block procedure to validation, where cold, non-reacting test data was first used for validation, followed by more complex reacting base flow validation.

Sinha, Neeraj; Brinckman, Kevin; Jansen, Bernard; Seiner, John

2011-01-01

480

Body With Thruster Model  

NSDL National Science Digital Library

The Body with Thruster Model shows the motion of a disk with an attached rocket engine. You can drag the engine to change its distance from the center of the disk and you can adjust the thrust of the rocket engine using sliders. The mass of the rocket and its connecting rod are assumed to be negligible. The trajectory of this single-body model is intuitively challenging and difficult to visualize. The Body with Thruster 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_newton_BodyWithThruster.jar file will run the program if Java is installed.

Christian, Wolfgang

2009-05-27

481

LAKE NUTRIENT MODELING STUDY  

EPA Science Inventory

Determining the effects of morphological conditions, turbidity and watershed land use / land cover patterns on nutrient levels in Central Plains lakes and reservoirs. The study involves intensive field monitoring for the calibration and verification of basin and watershed models...

482

Chesapeake Interactive Modeling Project  

NSDL National Science Digital Library

CHIMP is an interactive numerical model of Chesapeake Bay circulation. Users can vary freshwater flux and wind speed/direction and observe the response in real time, with several visualization options.

483

Analytic pulsar models  

NASA Technical Reports Server (NTRS)

An analytical procedure is given for solving the Einstein equations of a rotating fluid body. It is demonstrated that an analytic model of uniform denisty, representing a slowly rotating neutron star, can describe both differentially and uniformly rotating stars.

Adams, R. C.; Cohen, J. M.; Adler, R. J.; Sheffield, C.

1974-01-01

484

GEOS-5 Modeled Clouds  

NASA Video Gallery

This visualization shows clouds from a simulation using the Goddard Earth Observing System Model, Verison 5 (GEOS-5). The global atmospheric simulation covers a period from Feb 3, 2010 through Feb ...

485

Convex modeling with priors  

E-print Network

As the study of complex interconnected networks becomes widespread across disciplines, modeling the large-scale behavior of these systems becomes both increasingly important and increasingly difficult. In particular, it ...

Recht, Benjamin Harris, 1978-

2006-01-01

486

Standard model and beyond  

SciTech Connect

The ''standard'' SU(3)/sub C/ x SU(2)/sub L/ x U(1) model of strong and electroweak interactions elegantly incorporates all the proven symmetries and successes of the quark model, quantum electrodynamics, and the Four-Fermi theory. It correctly predicted weak neutral currents as well as the existence and properties of W/sup + -/, Z and gluons. ''Only'' the predicted Higgs scalar boson remains undiscovered. At this time there are no solid experimental results that cannot be accommodated by the standard model (at the 1 or 2 sigma level). Nevertheless, we do anticipate the emergence of new physics, beyond standard model expectations, which will hopefully provide guidance for theoretical advancement. Indeed, hints of some new phenomena may already be starting to appear in the CERN anti pp collider data. Details are discussed. 65 refs.

Marciano, W.J.

1985-01-01

487

Solar Furnance Model  

ERIC Educational Resources Information Center

Described is how to build a solar furnace model. A detailed list of materials and methods are included along with diagrams. This particular activity is part of an audiotutorial unit concerned with the energy crisis and energy alternatives. (MA)

Palmer, Dennis L.; Olsen, Richard W.

1977-01-01

488

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

489

URBAN AEROSOL MODELING  

EPA Science Inventory

Accurate numerical schemes have been developed for simulation of the condensation/evaporation processes with vapor conservation for a single component aerosol. These have been incorporated in modules which allow simulation of aerosol dynamics in models for dispersion and transpor...

490

Fibonacci Spiral Model  

NSDL National Science Digital Library

The Fibonacci Spiral Model draws a geometric spiral whose growth is regulated by the Fibonacci series. Its growth parallels the rapid growth of the series itself. The golden spiral gets wider (or further from its origin) by a factor for every quarter turn it makes. To produce a uniform distribution in the plane of the spiral, points are separated by the golden angle. The Fibonacci Spiral 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

2012-12-16

491

The Paradata Information Model  

E-print Network

Paradata is data on study processes and the collection of study data. Here we describe the development of a Paradata Information Model (PIM) in support of the National Children¹s Study (NCS) of the Eunice Kennedy Shriver ...

Greenfield, Jay; Carpenter, Danielle

2013-04-02

492

The Negotiation Training Model.  

ERIC Educational Resources Information Center

Discusses decision making and suggests that using simulation techniques based on a sophisticated decision support system facilitates the identification of utility-maximizing strategies. The negotiation training model is described, and preliminary results based on simulation runs are reported. (LRW)

Wilkenfeld, Jonathan; Kraus, Sarit; Holley, Kim M.

1998-01-01

493

Models and Simulations  

NSDL National Science Digital Library

Scientists use models and simulations to help them visualize, explain, and make predictions and hypotheses about the structures, properties, and behaviors of phenomena (e.g., objects, materials, processes, systems). The extremely small size and complexity

Krajcik, Joseph S.; Sutherland, Leeann M.; Stevens, Shawn Y.

2009-10-14

494

Linear Oscillator Model  

NSDL National Science Digital Library

The Linear Oscillator model solves the harmonic oscillator with or without linear damping and external sinusoidal force. The time evolution and phase space orbit are displayed. Optionally, the evolution of the mechanical energy appears in a separate window. The mouse may be used to select the initial position and velocity. 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 Linear Oscillator 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_oscillations_oscillator.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

495

Optical throughput model  

NASA Astrophysics Data System (ADS)

ITT Exelis builds electro optical telescopes and uses an optical throughput model in spreadsheet form to determine the transmission degradation due to contamination. The model can also be used to determine allowable contamination given a transmission requirement. Molecular contamination affects the transmission due to the absorbance of the optical contaminant while the particulate contamination affects the optical transmission due to obstruction and absorption of light, the model does not currently consider diffraction effects. The optical throughput model uses wavelength dependant absorption coefficients to determine the impact of the molecular contaminant. Optical transmission due to particles is analyzed by using the obscuration of the particle distribution. All optical elements in the telescope are analyzed by using the maximum angle of incidence for each optic. An expression was developed for non normal light assuming spherical particles and included light that was blocked by reflected incident light.

Elasky, Luke M.; Smallwood, Steven A.; Galvin, Roy P.

2012-10-01

496

Deriving Common Model Characteristics  

NSDL National Science Digital Library

In this activity, students confront several different models - from the DNA helix Watson and Crick constructed in their laboratory to a map of McDonalds density in the US - and work in small groups to derive their commonalities.

Momsen, Jennifer; Long, Tammy M.; Speth, Elena B.

497

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

498

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

499

Javelin Dynamics Model  

NSDL National Science Digital Library

The Javelin Dynamics Model simulates the throw of a javelin in a vertical plane. The user can change the initial velocity, angle of the javelin (theta), angle of the velocity vector (phi), angle of attack (phi), and angular velocity (omega). The Javelin Dynamics Model was developed as a final project in a sophomore-level Computational Physics course (Phy 200) 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.

Wall, Phillip

2012-07-18

500

Modeling of planarization technologies  

E-print Network

The need for better planarity becomes more critical in semiconductor manufacturing as dimensions and tolerance margins keep shrinking. The purpose of this thesis is to understand and model new technologies for the planarization ...

Truque, Daniel

2007-01-01