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Topic: Estimating parameters

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In the News (Wed 17 Apr 19)

  PEST - estimating parameters for any model
Most parameter estimation packages suffer from two serious drawbacks that inhibit their ability to optimize parameters for the plethora of computer simulation models that are used today in all fields of study.
The second disadvantage is that the performance of many commercial and public-domain estimators is seriously degraded when optimizing parameters for large numerical models or for the sometimes complex models used for simulating "messy" environmental processes.
Parameters and observations can be divided into subgroups for allocation of variables controlling calculation of model derivatives on the one hand and for assessing the contribution of various observations to the objective function on the other.
www.scisoftware.com /products/pest/pest.html   (706 words)

 The MathWorks - System Identification Toolbox - Estimating Parametric Models
The toolbox estimates model parameters and their uncertainties.
Estimation techniques include maximum likelihood, predictionerror minimization schemes, and such subspace methods as CVA, MOESP, and N4SID.
For example, you can estimate the saturation levels affecting the input current into a DC motor, or capture a complex nonlinearity at the output using a piecewise linear nonlinearity.
www.mathworks.com /products/sysid/description4.html   (359 words)

 Re: st: estimating parameters of Weibull distribution
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www.stata.com /statalist/archive/2003-02/msg00623.html   (276 words)

  Register of Ecological Models: CXTFIT
Three different one-dimensional transport models are included: (i) the conventional CDE; (ii) the chemical and physical nonequilibrium CDE; and (iii) a stochastic stream tube model based upon the local-scale CDE with equilibrium or nonequilibrium adsorption.
The two independent stochastic parameters in the stream-tube model are the pore water velocity, and either the dispersion coefficient, the distribution coefficient, or the nonequilibrium rate parameter.
These pairs of stochastic parameters are described with a bivariate lognormal probability density function (pdf).
dino.wiz.uni-kassel.de /model_db/mdb/cxtfit.html   (375 words)

  Estimating Parameters
The estimate of the population mean, mu, is the sample mean.
The second population parameter we want to estimate is the standard deviation, sigma.
We have developed estimates of the population mu and sigma as well as an estimate of the the standard error of the mean.
web.utah.edu /stat/materials/malloy/s-estimating/index.html   (1911 words)

  Method for estimating and correcting bias errors in a software air meter - Patent 5070846
By determining the input or model parameter bias, improved accuracy in the model predictions (and/or estimations) may be achieved by offsetting the input or model parameter by the estimated bias amount when calculating the model-based predictions.
Once the system bias is estimated, it is offset in subsequent predictions, thereby reducing the error between the predicted and measured values of the control parameter and increasing the accuracy of the estimations of the determinable vehicle parameter.
The sensors 68 measure the parameters of the engine assembly 66 and the resulting measurements are used to schedule the estimator correction coefficients comprising vector G at block 61 and to schedule the model parameters comprising matrices A, B, and C at block 75.
www.freepatentsonline.com /5070846.html   (5297 words)

 Estimating Cloth Simulation Parameters from Video   (Site not responding. Last check: )
Simulated annealing is used to minimize the frame by frame error between the metric for a given simulation and the real-world footage.
To estimate all the cloth parameters, we identify simple static and dynamic calibration experiments that use small swatches of the fabric.
Validation with the robot arm to show that the difference in motion is due to the parameters and not merely the driving motion.
graphics.cs.cmu.edu /projects/clothParameters   (238 words)

  Estimating parameters 1 - Wikipedia, the free encyclopedia   (Site not responding. Last check: )
Start the Estimating parameters 1 article or add a request for it.
Look for "Estimating parameters 1" in Wiktionary, our sister dictionary project.
Look for "Estimating parameters 1" in the Wikimedia Commons, our repository for free images, music, sound, and video.
www.sciencedaily.com /encyclopedia/estimating_parameters_1   (143 words)

 Estimating parameters and stochastic functions of one variable using nonlinear measurement models   (Site not responding. Last check: )
Estimating an unknown function of one variable from a finite set of measurements is an ill-posed inverse problem.
This is an extension of marginal likelihood estimators for the regularization parameter because we allow for a nonlinear relationship between the unknown function and the measurements.
The estimate of the function is then obtained by maximizing its a posteriori probability density function given the parameters and the data.
www.premier1.net /~bradbell/stochasticnonlinear.htm   (206 words)

 All publications sorted by year
In particular, reliable estimates of several critical forest canopy structure metrics, including canopy bulk density, canopy height, canopy fuel weight, and canopy base height, are required to accurately map the spatial distribution of canopy fuels and model fire behavior over the landscape.
The aims were (1) to test a proposed parameterization of the budget using two spectrally invariant canopy structural parameters (p and pt) governing canopy absorption and transmittance, respectively, and (2) to incorporate the effect of within-shoot scattering in the parameterization for shoot canopies.
The use of the parameter prediction method to describe small trees improved the accuracy considerably; the RMSE figures for estimates of timber volume and number of stems are 16.0-0x1.fe21808067b82p+0nd 49.2%, respectively.
www.geo.unizh.ch /rsl/services/bibliographies/lidar/Biblio/complete-bibliography.html   (14235 words)

 Techinal Note: Estimating Parameters of Nonlinear Segmented Models -- Fadel 87 (1): 169 -- Journal of Dairy Science
SAS program to estimate the parameters is in Appendix 2.
The parameters estimated (B1, B2, and B4) are assumed to approach
The estimates of B2 and B3 are 0.062 and 4.5 for
jds.fass.org /cgi/content/full/87/1/169   (1702 words)

 Construction estimating software for contractors and builders
Visual Estimator, construction cost estimating software that is fast and accurate.
Our estimating products cover general construction, remodel and rehab, insurance repair, home valuation, interior and exterior painting, roofing, flooring and jobcosting.
Whether you seek a general construction estimator or a specialty painting estimator, we are the source.
www.cprsoft.com   (1718 words)

 Estimating Parameters
The estimate of the population mean, mu, is the sample mean.
Unfortunately, it's going to be messier when we get to estimating population variance.
We have developed estimates of the population mu and sigma as well as an estimate of the the standard error of the mean.
www.psych.utah.edu /aoce/web-text/Estimating-Parameters99-12-15   (1911 words)

 Wang's PhD Abstract
At the heart of the problem an estimating function for the interest parameters, which is unbiased when the nuisance parameters are known, might become severely biased in the more realistic situation where one substitutes and estimator of ("profiles out") the unknown nuisance parameters in the estimating function.
Adopting this orthogonality condition, we propose second-order locally ancillary estimating function for studies with errors-in-covariates where the mismeasured unknown covariates are treated as fixed nuisance parameters.
The proposed estimating function is applicable with the information about the second moment of the data is incomplete and the second moment cannot be modeled accurately.
www.sph.emory.edu /bios/news/library/wangm.html   (500 words)

 Method and system for estimating performance metrics in a packet-switched communication network - Patent 6912216
The method of claim 11, wherein the at least one end-to-end quality of service parameter is selected from the group consisting of end-to-end packet loss probability, end-to-end packet delay distribution, and end-to-end packet delay jitter.
There is need for a process that estimates end-to-end packet loss, delay, and delay jitter for EIP network planning using the large deviation theory while taking into account changes in the number of active sources feeding the network.
Accordingly, the present invention is directed to a method for estimating end-to-end quality of service (QOS), such as packet loss, delay and delay jitter, in an enhanced IP network for use in network planning.
www.freepatentsonline.com /6912216.html   (2865 words)

 Estimating the dynamics of ecosystem CO2 flux and biomass production in agricultural fields on the basis of synergy ...
Estimating the dynamics of ecosystem CO flux and biomass production in agricultural fields on the basis of synergy between process models and remotely sensed signatures
The objective of this study was to investigate the potential of synergy between biophysical/ecophysiological models and remote sensing for the dynamic estimation of biomass and net ecosystem exchange of CO We obtained a long-term data set of micrometeorological, plant, and remote sensing measurements over well-managed uniform agricultural fields.
This synergistic approach allows the effective use of infrequent and multisource remote sensing data for estimating important ecosystem variables such as biomass growth and ecosystem CO flux.
www.agu.org /pubs/crossref/2006/2006JD007469.shtml   (436 words)

 Estimating the parameters in a dynamics model of a robot and its applications
Estimating the parameters in a dynamics model of a robot and its applications
This article discusses a method for measuring the parameters which appear in the dynamics equations i.e.
It is possible to predict the control signals for each motor, if the dynamics model of the robot is available and parameters are known.
www.robotics.lu.se /publications/1997/hamid97a/HTML/mforce3_html.html   (235 words)

 Estimating Optimal Parameters for MRF Stereo from a Single Image Pair
This approach is based on a new formulation of stereo as a maximum a posterior (MAP) problem in which both a disparity map and MRF parameters are estimated from the stereo pair itself.
We present an iterative algorithm for the MAP estimation that alternates between estimating the parameters while fixing the disparity map and estimating the disparity map while fixing the parameters.
The estimated parameters include robust truncation thresholds for both data and neighborhood terms, as well as a regularization weight.
csdl2.computer.org /persagen/DLAbsToc.jsp?resourcePath=/dl/trans/tp/&toc=comp/trans/tp/2007/02/i2toc.xml&DOI=10.1109/TPAMI.2007.36   (801 words)

 Identification of the parameters
In fact, by arranging simple experiments when only one joint performs the movement it is possible to identify all important robot properties, such as mass of the arms, moment of inertia and friction constant.
The most suitable method applicable to this case is known as ``parameter estimation method'' which uses a theoretical model and tries to fit measured data in order to minimize an error function, see [12, 19].
At last parameters are estimated by an evaluation method which depends on the model.
www.robotics.lu.se /publications/1997/hamid97a/HTML/node5.html   (550 words)

 The Study of Plant Disease Epidemics
This theory demonstrates how different levels of mathematical complexity can lead to unifying principles of disease invasion, persistence, and rates of temporal increase and disease expansion from foci.
In addition, the book shows how disease control strategies are intricately related to fundamental population-biology parameters.
The information on modeling and statistical analysis provides the needed tools and procedures for researchers to help them properly measure and analyze collected epidemiological data and maximize its value.
www.shopapspress.org /stofpldiep.html   (622 words)

 Ultrasonic apparatus for estimating artery parameters invention
The severity of an aneurysm may be estimated by considering its maximal diameter.
In order to early diagnosing aneurysms in aorta, the medical field has a need for non-invasive means for providing aorta images together with clear quantified indications of the aortic distensibility, which is a measure that is used by clinicians together with dilation information.
This image processing system offers the advantage that the aorta wall behavior is made clearly visible together with the parameters that are useful for the clinician in the study of these Abdominal Aortic Aneurysms.
www.freshpatents.com /Ultrasonic-apparatus-for-estimating-artery-parameters-dt20060413ptan20060079781.php   (1213 words)

 Generalized Estimating Equations
Note that this is not in general a likelihood-based method of estimation, so that inferences based on likelihoods are not possible for GEE methods.
The GENMOD procedure can estimate the working correlation from data containing both types of missing values using the all available pairs method, in which all nonmissing pairs of data are used in the moment estimators of the working correlation parameters defined previously.
Estimates of the parameters for other working correlation types are computed in a similar manner, using available nonmissing pairs in the appropriate moment estimators.
www.sfu.ca /sasdoc/sashtml/stat/chap29/sect38.htm   (1823 words)

 Estimation theory   (Site not responding. Last check: )
Estimation theory is a branch of statistics and signal processing that deals with estimating the values of parameters based on measured/empirical data.
That proportion is the unobservable parameter; the estimate is based on a small random sample of voters.
One common estimator is the minimum mean squared error (MMSE) estimator, which utilizes the error between the estimated parameters and the actual value of the parameters
www.omniknow.com /common/wiki.php?in=en&term=Estimating_parameters   (2713 words)

 vgn-ext-hidden_PubMed   (Site not responding. Last check: )
Estimating the parameters of a model for protein-protein interaction graphs.
We show that unchorded four-cycles are characteristic motifs under this model and that the count of unchorded four-cycles in the graph is a reliable statistic on which to base parameter estimation.
Finally, we test our model against a range of experimental data, obtain parameter estimates from these data and investigate possible improvements in the model.
www.asco.org /portal/site/ASCO/menuitem.a3fb42726842a82627c4c291ee37a01d/?vgnextoid=d70b3608f9958010VgnVCM100000f2730ad1RCRD&index=n&pmid=16857705   (183 words)

 Calculating Hydrologic Parameters for Estimating Surface Water Flow with GIS
Once the set of hydrologic parameters at each control point was extracted from the GIS datasets, the contributing area at the control points was compared to USGS estimates of contributing area.
Secondly, the upstream averages of the parameter values at the control points for curve number and mean annual precipitation will be adjusted to reflect the loss of weighting on downstream influence due to non-contributing areas.
This is a result of the assumption that the original incremental parameter values would be preserved in all subwatersheds but their weighting downstream would be reduced due to a reduction in their contributing area.
ceprofs.tamu.edu /folivera/TxAgGIS/Spring2002/Hoffpauir/hoffpauir.htm   (3055 words)

 Estimating a Latent Trait Model by Factor Analysis of Tetrachoric Correlations
Threshold parameters are estimated by applying the probit function to the marginal response proportions for each item.
To estimate the correlation parameters of the latent trait model, we will first calculate the matrix of tetrachoric correlations for all item pairs, and will then factor analyze this matrix.
These loadings, the item--factor correlations, are the correlation parameters we seek--that is, the estimated correlations of latent continuous variables with the factors.
ourworld.compuserve.com /homepages/jsuebersax/irt.htm   (3349 words)

 Background Paper: A Summary of Alternative Methods for Estimating Potential GDP   (Site not responding. Last check: )
That is, estimating the trend in a data series is especially difficult near the end of a data sample, making the estimate most uncertain for the period of greatest interest: the recent past.
CBO's estimate of potential output is based on the framework of a textbook model of long-term economic growth, the Solow growth model.
The parameters of these equations can be estimated using statistical techniques, and under certain assumptions, the equations can be used to calculate potential output.
www.cbo.gov /showdoc.cfm?index=5191&sequence=0   (3412 words)

 Estimating Mutation Parameters, Population History and Genealogy Simultaneously From Temporally Spaced Sequence Data -- ...
Parameter estimates for 10 independent analyses of the pretreatment dataset assuming constant population size and HKY model of mutation
Parameter estimates for 10 independent analyses of the pretreatment dataset assuming exponential growth and GTR model of mutation
The estimated 95% HPD interval for the mutation
www.genetics.org /cgi/content/full/161/3/1307   (5702 words)

 Estimation and Classification of Timbre
One of the major drawbacks of dynamic parameter estimation is that it explicitly encodes for each moment of a sounds evolution in terms of articulator activity.
The parameters that the inverse model estimates are then passed through to the physical environment and the environment performance error is used to fine-tune the inverse estimator.
We chose to implement a static parameter estimator whose input is a dynamic sound representation and whose output is a set of stationary parameters; see Figure 3.
xenia.media.mit.edu /~mkc/mitpress/node9.html   (410 words)

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