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Topic: Computer models


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In the News (Fri 4 Dec 09)

  
  Population Computer Models
These models are the basis for the program or computer model that you'll be using in the last sections of the lesson.
Models are also basic tools used by Population Ecologists in the study and analysis of populations.
A computer model can display the results graphically as it does the calculations, and it can also take the input through a nice user interface (by pointing and clicking with the mouse).
www.arcytech.org /java/population/models.html   (1405 words)

  
 Hadley Centre: Climate Models   (Site not responding. Last check: 2007-11-07)
This type of model predicts changes in sea-surface temperatures and sea ice by treating the ocean as though it were a layer of water of constant depth (typically 50 metres), heat transports within the ocean being specified and remaining constant while climate changes.
This kind of model is useful for simulating what the climate would be like for some fixed level of carbon dioxide, but it cannot be used for predicting the rate of change of climate because this is largely determined by processes in the ocean interior.
The carbon cycle model is needed in order to capture several important climate feedbacks on carbon dioxide concentration, for instance fertilisation of plant growth by carbon dioxide and uptake or outgassing of carbon dioxide by the oceans.
www.met-office.gov.uk /research/hadleycentre/models/modeltypes.html   (939 words)

  
 Some operational forecast models   (Site not responding. Last check: 2007-11-07)
Relocatable models are very limited on the size of the geographical area for which they can forecast, but these models have very high resolutions, or very small forecast grid boxes.
The ocean model coupled with the atmospheric model is used to forecast events such as an El Nino warming event in the Pacific Ocean and in long range seasonal outlooks.
The model does not forecast for large distances away from the hurricane because its main focus is the development and the movement of the hurricane.
www.usatoday.com /weather/wmodlist.htm   (1426 words)

  
 Reasoning Errors In The Current Models of Human Cognition
Modeling on computer is regarded as a useful way of 'flushing out' all the details of the model, thus eliminating the 'ignoring complexity' problem.
In its outcome, this error is equivalent to the model space size error, but it stems from different source: in the model space size error the researcher knows that the feature is complex, but is unaware of the model space size problem, while here the researcher is unaware of the complexity of the feature.
The 'computational' approach may be an explicit version of this error, depending on what is assumed in the computational model.
www.human-brain.org /errors.html   (11784 words)

  
 The Philosophical Computer - Introduction
Our experience is that the environment of computer modeling often leads one to ask new questions, or to ask old questions in new ways-- questions about chaos within patterns of paradoxical reasoning or epistemic crises, for example, or Hobbesian questions asked within a spatialization of game-theoretic strategies.
Models prove useful both in exposition and exploration precisely because they're simpler, and therefore easier to handle and easier to track, than the bewildering richness of the full phenomena under study.
Computer modeling is new in philosophy and thus maybe misunderstood.
www.sunysb.edu /philosophy/faculty/pgrim/intro.html   (3241 words)

  
 Arctic Climate simulated by computer models - Lynch
In such a situation it is possible that the global model response to anthropogenic forcing would have a weaker projection onto the model's patterns of internal variability than in the real world.
The results so far are strongly model dependent, which points to the need for better understanding of the important physical mechanisms and dominant feedbacks in the climate system, and the way these processes interact on a range of timescales.
Our understanding of many of these mechanisms or their interactions is sufficiently limited that there remains a strong role for limited area models and individual process models, which are not limited by the important of model bias and errors from other regions of the globe, to continue the investigation.
www.arctic.noaa.gov /essay_lynch.html   (803 words)

  
 Computer modelling
With a computer model, it is possible, within a few days of development, for it to become so complex that it is a virtual impossibility for an outsider to understand it fully.
When we were pioneering the applications of computer modelling about forty years ago, we soon came to the conclusion that a model is useless unless it can be tested against reality.
If a model gives a reasonably accurate prediction on a simple system then we have reasonable, but not irrefutable, grounds for believing it to be accurate in other circumstances.
www.numberwatch.co.uk /computer_modelling.htm   (735 words)

  
 Models
It is important to note that a model may represent some or all of the properties of the system.
One of the advantages of the use of models, is that experiments may be performed that would be difficult, impossible (or even immoral) on the original system.
Accuracy--Some models have been attacked because one existing system is simply assumed to model another (because of outward similarities).
people.sunyit.edu /~millerd1/MODEL.HTM   (616 words)

  
 Forecasters rely on computer models   (Site not responding. Last check: 2007-11-07)
Computer models depend on the fact that mathematical equations can describe the physical changes that govern the weather, just as equations describe movements of the solar system well enough for solar and lunar eclipses to be predicted years, even centuries, in advance.
As computer technology advanced, the complexity of the forecast models increased and more of the dynamical and physical factors influencing the atmosphere were taken into account.
Model available for Microsoft Windows/NT A state-of-the-art weather forecast model used worldwide by government and private agencies is now available in a desktop version using Microsoft Windows/NT.
www.usatoday.com /weather/wmodels.htm   (749 words)

  
 GIZA PLATEAU COMPUTER MODEL
To accomplish this a computer model of the entire plateau and its architectural components had to be created from published maps, survey, and excavation reports.
Using the ARRIS program's Modeling and Rendering module, each wireframe model had surface geometry applied to it so that it could be rendered as a solid object, and then each was added to the surface terrain model in their appropriate locations.
Fortunately for her, our computer model of the Zoser complex was easily adapted to illustrate her forthcoming article correlating the three stelae beneath the step pyramid and the three stelae associated with the south tomb.
oi.uchicago.edu /OI/DEPT/COMP/GIZ/MODEL/Giza_Model.html   (1625 words)

  
 Computer Models of Evolution. by Brig Klyce   (Site not responding. Last check: 2007-11-07)
These abstract computer processes make it possible to pose and answer questions about evolution that are not answerable if all one has to work with is the fossil record and fruit flies.
The hallmark of complexity theory is the extensive use of information theory and computers to model the behavior of notoriously complex problems such as economic markets, protein folding, and evolution.
When the computer's memory is full, the older or more defective organisms are "killed off." The outcome of this artificial process about which Gell-Mann has the most to say is the evolution of a more compressed version of the original ancestor, one with only 36 instructions instead of eighty (p 315).
www.panspermia.org /computrs.htm   (3226 words)

  
 Federal Consumer Information Center: About... Buying a Computer
Computers can be categorized into two basic operating systems or types-those designed primarily for graphics work and those primarily intended for word processing.
If you're buying the computer for your child's use, see what kind of computer is used in his or her classroom.
Cache is used by the computer to quickly move data between the RAM and the CPU.
www.pueblo.gsa.gov /cic_text/misc/buy-computer/buycomp.htm   (2104 words)

  
 Information Sources: Databases & Software: Models
Computational Toxicology - The application of mathematical and computer models to predict adverse effects and to better understand the mechanisms through which a given chemical induces harm.
ReachScan is an integrated surface water modeling and database system to estimate surface water concentrations, and determine the presence of endangered species or critical habitats in the county of a releasing facility.
Urban Airshed Model (UAM) - a three-dimensional photochemical grid model designed to calculate the concentrations of both inert and chemically reactive pollutants by simulating the physical and chemical processes in the atmosphere that affect pollutant concentrations.
www.epa.gov /epahome/models.htm   (1280 words)

  
 USGS Learning Web :: Paper Models
Illustrates, through computer animation and a paper model, why there are changes on the ice sheet that covers the Antarctic continent.
This report shows, by means of a computer animation and paper models, how deltas are affected by fresh and salt water currents, topography, and location.
The first model is a shield volcano that extends above the sea level, the second is a volcano with a fringing reef of coral, the third is a volcano with a coral reef and a lagoon, and the fourth is an atoll.
interactive2.usgs.gov /learningweb/teachers/paper_models.htm   (826 words)

  
 Computer Models
Companion models use a statistical data base to estimate what sort of temperatures and precipitation might occur for a particular city.
Such a model might be run as often as once every three hours, with data points separated by only a few miles or kilometers.
A modeling framework suitable for both study and prediction is being developed by NCAR and five collaborators.
www.ucar.edu /research/tools/models.shtml   (756 words)

  
 Appearance Models for Computer Graphics and Vision
In vision, texture and reflection models can be used to guide the acquisition of computer models of different scenes and objects, as well as the recognition of these scenes and objects in images.
Typically, the output of computer graphics is pictures for humans to see--hence knowing the characteristics of human vision enables concentrating on what matters.
Computer vision can be used to acquire models of scenes for use in computer graphics; and graphics rendering can in turn serve as a test for the adequacy of these models.
www.cs.berkeley.edu /Research/Projects/vision/classes/cs294-appearance_models/sp2001   (885 words)

  
 The head of Michelangelo's David   (Site not responding. Last check: 2007-11-07)
Although this 1mm model represents only 1/16th of the (0.29mm) data we have acquired, it is good enough to begin comparing it to a photograph (shown at right), taken from approximately (but not exactly) the same viewpoint.
Although our model is slightly softer in the fine details than the statue, we expect that higher-resolution models, on which we are currently working, will eliminate most of this softness.
The triangles in this mesh are computed from a volumetric representation of the statue, and their size depends on the resolution of this volume.
graphics.stanford.edu /projects/mich/head-of-david/head-of-david.html   (1449 words)

  
 Directed-Graph Epidemiological Models of Computer Viruses
Despite serious concerns raised by the proven ability of computer viruses to spread between individual systems and establish themselves as a persistent infection in the computer population, there have been very few efforts to analyze their propagation theoretically.
The strong analogy between biological viruses and their computational counterparts has motivated us to adapt the techniques of mathematical epidemiology to the study of computer virus propagation.
We conclude that an imperfect defense against computer viruses can still be highly effective in preventing their widespread proliferation, provided that the infection rate does not exceed a well-defined critical epidemic threshold.
www.research.ibm.com /antivirus/SciPapers/Kephart/VIRIEEE/virieee.gopher.html   (317 words)

  
 New NASA Computer Models May Lead To Quake Forecast System
Advanced computer simulation tools now being developed by NASA and university researchers may soon give scientists new insights into the complex and mysterious physics of earthquakes and enable vastly improved earthquake forecasting.
Virtual Hurricanes: Computer Model Pushes The Frontier (August 3, 2001) -- In a key step toward improving hurricane prediction, scientists at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., have reproduced in a computer model the fine- scale structure...
Under a joint NASA/Department of Energy study lead by Dr. John Rundle, director of the Center for Computational Science and Engineering at the University of California at Davis, Virtual California was used to identify regions of the state with elevated probabilities of quakes over the next decade.
www.sciencedaily.com /releases/2003/05/030523075515.htm   (1042 words)

  
 Computer Models, Page 1 of 13   (Site not responding. Last check: 2007-11-07)
This module focuses on computer models that are run by the National Centers for Environmental Prediction (NCEP) and are used for forecasting the day-to-day weather in the United States.
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.
These individual models are all quite different from each other in one essential aspect or another, either in their formulation or their implementation.
www.met.tamu.edu /class/ATMO151/tut/models/modelmain.html   (195 words)

  
 Apple - PowerBook G4   (Site not responding. Last check: 2007-11-07)
Gigabit Ethernet comes built into the 17-inch and 15-inch models (10/100 Ethernet on the 12-inch model) and a 56K V.92 modem in all models, which means that if your ISP supports the V.92 standard, you can put your Internet connection on hold while you answer an incoming phone call.
And the 15- and 17-inch models now sport the ATI Mobility Radeon 9700 featuring 64MB and 128MB of DDR SDRAM, respectively, with an option to rev the 15-inch PowerBook up to 128MB of video memory.
Every PowerBook G4 computer supports DVI output, providing the highest video output quality with a pure digital connection all the way from the graphics processor to your DVI-equipped display or projector.
www.apple.com /powerbook   (1426 words)

  
 Interactive models for Analytical Chemistry Instruction   (Site not responding. Last check: 2007-11-07)
This is a collection of interactive computer models and simulations of common analytical instruments and techniques.
They were designed to be used by individual students either as homework assignments, for in-class use in a computer lab environment, or in the laboratory for the analysis of student-generated data.
These models were created using WingZ, a 90's vintage object-oriented spreadsheet with a built-in macro language that was available from Investment Intelligence Systems Corp.
www.inform.umd.edu /EdRes/Topic/Chemistry/ChemConference/Software/Spreadsheets/WWW   (851 words)

  
 Hurricane Models
To forecast the track and intensity of tropical cyclones, the NHC uses several different mathematical computer models that represent the tropical cyclone and its environment in a greatly simplified manner.
It is important to know that these models are only run a few times a day and cannot, therefore, take into account all of the short-term changes the atmosphere is constantly undergoing.
When the models do disagree, hurricane forecasters must use their experience and judgment to decide which model is performing the best under the current conditions.
www.nhc.noaa.gov /HAW2/english/basics/models.shtml   (493 words)

  
 usnews.com: Using computer models to predict elections (2/10/04)
These models usually look at some combination of economic and political factors to make their forecasts.
But since creating his model of voting behavior in 1978, Fair’s forecasts have been uncanny in predicting the vote share of the incumbent party.
Since my original piece on Fair’s model, an economic research firm called Macroeconomic Advisers (founded by former Federal Reserve governor Lawrence Meyer) issued a study that tweaked Fair’s model by eliminating the political component and substituting a couple of different economic variables that it determined were more statistically significant.
www.usnews.com /usnews/tech/nextnews/archive/next040210.htm?track=rss   (606 words)

  
 moreweather.com - Numerical Weather Prediction
Tables have been placed on separate pages to accomodate slow internet connections.
Use the NWP MODEL INDEX to move from page to page.
Click on any name or dot to go to that location's table.
www.moreweather.com /models   (44 words)

  
 Computer Models Used To Improve Efficiency Reduce Costs For Species Preservation
Cincinnati -- A University of Cincinnati computer model already used by major corporations to plan efficient distribution networks is now being used by conservation researchers to study the most cost-effective plans for species preservation.
Camm's computer model can be adjusted to handle both species distribution and land type.
Camm is quick to point out that his optimization model does not cover all the variables.
www.sciencedaily.com /releases/1998/03/980327074559.htm   (808 words)

  
 Computer Model Evaluation Workshop
Moreover, under the rubric of ``model evaluation'' can be found everything from eyeball assessments to rigorous and formal characterizations, with some judgments derived from an aggregate measure of fit and others from a focus on certain key features of model output.
But these procedures need to be systematically considered in the context of particular model evaluation strategies: for instance, a method that may work well for comparing computer model output to data may not work well for comparing two sets of computer model output.
Finally, a key concern is how to effectively characterize uncertainty in computer models, taking into account such things as questionable data quality, model mis-specification in the computer code, and dependencies of all sorts.
www.niss.org /cmworkshop.html   (651 words)

  
 Computer Models Aid Understanding Of Antibody-dependent Enhancement In Spread Of Dengue Fever
Some viruses’ ability to exploit the human body’s own defenses to increase their replication may be both a blessing and curse, according to the findings of a study conducted by researchers at the Johns Hopkins Bloomberg School of Public Health.
Using computational models based on epidemic theory, the researchers examined the dynamic role antibody-dependent enhancement plays in the spread of dengue viruses.
Although the computer models were specifically developed for dengue, the researchers believe the results could apply to any disease in which partial immunity increases pathogen replication rates.
www.sciencedaily.com /releases/2005/10/051015092305.htm   (734 words)

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