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2nd Pan-American Conference on Unsaturated Soils ((PanAm-UNSAT)

作者： Ellithy, Ghada S. Vahedifard, Farshid Rivera-Hernandez, Xavier A. US Army Corps Engineers Engineer Res & Dev Ctr 3909 Halls Ferry Rd Vicksburg MS 39180 USA Mississippi State Univ Dept Civil & Environm Engn Mississippi State MS 39762 USA

ISBN: (数字)9780784481684

ISBN: (纸本)9780784481684

Proper determination of the soil-water characteristic curve (SWCC) plays an important role in the accuracy of any modeling attempt involving variably saturated soils such as transient unsaturated seepage analysis. While the SWCC can be directly measured, several predictive models have been developed over the past two decades and are employed in practice because of their simplicity, and the lower cost, and time needed to obtain their input parameters. The predictive models are commonly developed through multiple regression analysis over a large number of measured SWCCs to establish an empirical correlation between the SWCC model parameters and soil index properties such as grain size distribution and Atterberg limits. This study evaluates the performance of seven predictive models to estimate the van Genuchten SWCC model parameters a, n, and theta(r) that represent the air entry value (AEV), slope of the curve, and the residual water content, respectively. For this purpose, the transient release and imbibition method (TRIM) device is used in the laboratory to obtain the van Genuchten SWCC of silty sand samples collected from a setback levee. The van Genuchten model parameters measured in the laboratory are compared against those estimated using the predictive models. The comparison shows that using predictive models can lead to over two orders of magnitude difference in a, a ratio of theta(r) to theta(s) between 0.06 and 0.21, and an n value between 1.25 and 2.85 for the tested soil. The aforementioned differences can lead to significant variations in transient seepage analysis results, a factor which needs to be carefully taken into consideration when using predictive models in practice.

关键词： Prediction models Vans TNIP1 gene model parameters index properties Saturated soils dust sand

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Analysis of HIV-1 Compartmental model parameters using Bayesian MCMC Estimation

Analysis of HIV-1 Compartmental Model Parameters using Bayes...

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American Control Conference

作者： Cardozo, Erwing Fabian Zurakowski, Ryan Attoh-Okine, Nii Univ Delaware Dept Elect & Comp Engn Newark DE 19716 USA

ISBN: (纸本)9781479932740

In previous work Bayesian Markov-Chain Monte Carlo techniques were used to identify HIV dynamic parameters from patient data. This study used viral load data from HIV patients during interrupted cycles of antiretroviral drugs. The data were fit to a well-established single-compartment model of HIV dynamics. Experimental evidence supports the use of a new compartmental model that includes the re-circulation of T-cells between anatomical reservoirs. If the infection dynamics are indeed compartmentalized, it is not clear how this would affect the estimated values of the dynamic parameters. In this study, we identify parameters of the simple, one-compartment model using data generated by the complex spatial model, and investigate the bias in parameter values introduced by this method. Multiple instances of simulated noisy data was generated from the spatial model using parameter estimates from previous studies. Markov-Chain Monte Carlo methods were used to identify parameter values for the simple model from the simulated data, and the identified values were compared with the true values to determine the existence of bias. The maximum likelihood bias in the median estimates of the proliferation, death and infection rate parameters for target T-cells and virion production rates were on average smaller than one standard deviation of the reported parameter uncertainties for the simple model. The median estimates of the death rate of infected cells and the efficacy of the drug exhibited an average positive bias (the posteriors were larger than the priors) that was larger than one-standard deviation of the prior for all patients. Neglecting the spatial dynamics does not seem to significantly affect the estimation of the proliferation, death, and infection rate parameters for target T-Cells. Conversely, the values of the infected cell death rates and drug efficacies exhibited a consistent bias when estimated using the simplified model. Neglecting spatial dynamics will result i

关键词： Data models Drugs Equations Human immunodeficiency virus Load modeling Mathematical model Maximum likelihood estimation Biological systems Identification HIV data models Load modeling biological organs maximum likelihood estimation Pharmaceutical Preparations Mathematical model Mortality T-Lymphocytes Monte Carlo technique dynamic parameter noisy data Compartmental models model parameters

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Uncertainty Budget for Distribution Grids Analysis. A Study Case on model parameters

Uncertainty Budget for Distribution Grids Analysis. A Study ...

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7th International Symposium on Advanced Topics in Electrical Engineering (ATEE)

作者： Florea, Irina Mangeac Naumof, Melania Dumitrescu, Ana Maria Univ Politehn Bucuresti Fac Elect Engn Bucharest Romania

ISBN: (纸本)9781457705076

Smart Grids paradigm includes the future control of distribution grids which evolves as to include novel components distributed generation, demand side control, storage and loads as part of prosumer operation. Control algorithms have to rely on accurate information. Measurements from a limited set of network nodes have to be further processed in order to derive the electrical quantities fully describing the considered grid. Uncertainties in the measurement chain but also in the network model (mostly from incomplete knowledge of the model electrical parameters) will determine a bias in the state estimation. In this paper one of the model components is considered - the equivalent circuit of the cable line belonging to a generic distribution grid - and described along with associated uncertainties. In order to minimize the resulting uncertainty for the computed electrical quantities, a special case, when phasor measurement units (PMU) are used for deriving the steady state parameters, is considered.

关键词： Power grids network node electrical quantities State estimation model parameters network model Phasor measurement units Incomplete knowledge equivalent circuits Uncertainty cable line model structures

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CPT-Based Random Field model parameters for Liquefiable Silty Sands

CPT-Based Random Field Model Parameters for Liquefiable Silt...

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Geo-Risk Conference

作者： Bong, Taeho Stuedlein, Armin W. Oregon State Univ Sch Civil & Construct Engn 101 Kearney Hall Corvallis OR 97331 USA

ISBN: (数字)9780784480724

ISBN: (纸本)9780784480724

Although soil is not deposited as a result of random processes, it is often convenient to treat the inherent variability within a given soil unit as a random field. Some reliability-based design codes require the adjustment of resistance factors within the LRFD framework based on site variability;however, there is a general lack of familiarity with methods to determine and model the inherent spatial variability of soil stratigraphy. Thus, random field model parameters that have been reported in the literature are often used instead of those developed from site-specific in-situ data. Studies of well-documented sites can help to improve the range in random field model parameters appropriate for various soils. In this study, the inherent variability of a liquefiable, silty sand soil present at a test site developed to evaluate liquefaction mitigation methods is characterized. Random field geostatistical model parameters were estimated for the corrected cone penetration resistance and sleeve friction resulting from the cone penetration tests (CPTs). Stationarity of individual soil layers was achieved using linear trend removal. The coefficient of inherent variability and scale of fluctuation determined using fitted autocorrelation models and differences between the model parameters is described. The random field model parameters presented herein provides a comprehensive set of parameters for modeling the spatial variability of potentially liquefiable silty sands.

关键词： model parameters dust sand soil layer Random soil units resistance factor Design specifications Fields Soil resistance to penetration Stochastic Processes site-specific Familiarity

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A novel approach to the fully automatic extraction of Fujisaki model parameters 25

A novel approach to the fully automatic extraction of Fujisa...

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IEEE International Conference on Acoustics, Speech, and Signal Processing

作者： Mixdorff, H Dresden Univ Technol D-01062 Dresden Germany

ISBN: (纸本)0780362934

The generation of naturally-sounding F0 contours in TTS is important for the intellegibility and perceived naturalness of synthetic speech. In earlier works the author developed a linguistically motivated model of German intonation based on the quantitative Fujisaki model of the production process of F0. The extraction of parameters for this model from the extracted F0 contour, however, poses problems since model components are superimposed in a particular contour and cannot be calculated directly. The current paper introduces a novel fully-automatic multi-stage approach which was applied to a larger speech database of German. After explaining the modeling procedure in detail, the paper presents first results concerning the relationship between the Fujisaki parameters and the linguistic information underlying an utterance.

关键词： automatic extracting linguistic data intelligibility Production Processes model parameters Speech

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AN EMPIRICAL ESTIMATION OF STATISTICAL INFERENCES FOR SYSTEM DYNAMICS model parameters

AN EMPIRICAL ESTIMATION OF STATISTICAL INFERENCES FOR SYSTEM...

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Winter Simulation Conference

作者： Mesabbah, Mohammed Rashwan, Wael Arisha, Amr Dublin Inst Technol Coll Business Grp 3S Aungier St Dublin 2 Ireland

ISBN: (纸本)9781479974863

For system dynamics simulation (SD) models, an estimation of statistical distributions for uncertain parameters is crucial. These distributions could be used for testing models sensitivity, quality of policies, and/or estimating confidence intervals for these parameters. Assumptions related to normality, independence and constant variation are often misapplied in dynamic simulation. Bootstrapping holds a considerable theoretical advantage when used with non-Gaussian data for estimating empirical distributions for unknown parameters. Although it is a widely acceptable approach, it has had only limited use in system dynamics applications. This paper introduces an application of Direct Residual Bootstrapping (DRBS) for statistical inference in system dynamic model. DRBS has been applied successfully to 'The Irish Elderly Patient Delayed Discharge' dynamic model to estimate empirical distribution for some unknown parameters with a minimal computation effort. The computational results show that bootstrapping offers an efficient performance in cases of no availability of prior information of model parameters.

关键词： geriatrics parameter estimation statistical analysis statistical distributions DRBS SD model The Irish Elderly Patient Delayed Discharge dynamic model confidence interval estimation direct residual bootstrapping empirical distribution estimation model sensitivity testing nonGaussian data policy quality statistical distribution estimation statistical inference system dynamics model parameters system dynamics simulation model Computational modeling Correlation Data models Equations Estimation Mathematical model Optimization Statistical inference statistical distribution data models Geriatrics Computational modeling Parameter estimation Mathematical model bootstrapping System dynamics Unknown parameter Statistical methods interval estimation model parameters

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Trip-synchronous parameter estimation of vehicle and tire model parameters as virtual sensor for load-sensitive lightweight vehicles

Trip-synchronous parameter estimation of vehicle and tire mo...

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IEEE International Conference on Vehicular Electronics and Safety (ICVES)

作者： Kohlhuber, Florian Buechner, Stefan Lienkamp, Markus Tech Univ Muenchen Inst Automot Technol Boltzmannstr 15 D-85748 Garching Germany

ISBN: (纸本)9781479918829

Vehicle dynamics controls, like yaw rate controls, need accurate values for vehicle inertial and tire parameters. Normally those can be assumed to remain nearly constant for everyday car trips, but looking at vehicles with very low curb weights, these parameters can change on a wide range due to different passenger or luggage loads. This effect is analyzed with several load scenarios. A Kalman filter based algorithm is presented that is able to determine all vehicle and tire parameters with standard sensors during random everyday trips and within short time. Therefore, an extended nonlinear vehicle model is defined that is able to represent vehicle behavior for everyday driving profiles very well. The estimator is validated using real-world steering and velocity profiles.

关键词： vehicle Parameter estimation load-sensitive model parameters Vehicle performance Light duty vehicles Vehicle model Vehicle dynamics VELOCITY PROFILING LOAD Kalman filters rate control Lightweight Sensors

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Determination of model parameters for the Hardening Soil model

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TRANSPORTATION INFRASTRUCTURE GEOTECHNOLOGY 2020年第1期7卷 55-68页

作者： Wu, Jonathan T. H. Tung, Sheldon Chih-Yu Univ Colorado Denver Reinforced Soil Res Ctr Denver CO 80217 USA

The Hardening Soil model, an elasto-plastic second-order hyperbolic isotropic hardening model, in Plaxis has seen many applications in finite element analysis of various earth structures. This technical note presents a protocol for determination of the model parameters of the Hardening Soil model from a set of triaxial compression tests. The technical note also describes details about how to determine the Mohr-Coulomb strength parameters c and phi for well-compacted fills (with and without cohesion), of which the failure envelopes are typically curved. The motivation for preparing this technical note came from a study on analysis of field-scale soil-geosynthetic composites in which the soil model and model parameters deduced from triaxial tests were able to predict with very good accuracy "all" measured results of five field-scale soil-geosynthetic composites under increasing applied vertical loads up to 1000 kPa (approximately five times the load level commonly used in design of reinforced soil bridge abutments). The model parameters were determined by a well-defined protocol. The protocol should be of value to researchers and engineers who use the soil model for sophisticated finite element analysis and design of earth structures.

关键词： Hardening Soil model model parameters Plaxis Finite element analysis Mohr-Coulomb strength parameters Curved failure envelope

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An analytical study of relay neuron's reliability: Dependence on input and model parameters

An analytical study of relay neuron's reliability: Dependenc...

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33rd Annual International Conference of the IEEE Engineering-in-Medicine-and-Biology-Society (EMBS)

作者： Agarwal, Rahul Sarma, Sridevi V. Johns Hopkins Univ Dept Biomed Engn 3400 N Charels St Baltimore MD 21218 USA Johns Hopkins Univ Fac Biomed Engn Baltimore MD 21218 USA

ISBN: (纸本)9781424441228

Relay neurons are widely found in our nervous system, including the Thalamus, spinal cord and lateral geniculate body. They receive a modulating input (background activity) and a reference input. The modulating input modulates relay of the reference input. This modulation is critical for correct functioning of relay neurons, but is poorly understood. In this paper, we use a biophysical-based model and systems theoretic tools to calculate how well a single relay neuron relays a reference input signal as a function of the neuron's electro physiological properties (i.e. model parameters), the modulating signal, and the reference signal parameters. Our analysis is more rigorous than previous related works and is generalizable to all relay cells in the body. Our analytical expression matches relay performance obtained in simulation and suggest that increasing the frequency of a sinusoidal modulating input or decreasing its DC offset increases the relay cell reliability.

关键词： Biological system modeling Computational modeling DC offset Neurons Orbits Relays Reliability Steady-state bioelectric phenomena biophysical-based model cellular biophysics lateral geniculate body model parameters modulating signal nervous system neuron e

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Simulation and Analyzing on model parameters Effect of BISRA-AGC

Simulation and Analyzing on Model Parameters Effect of BISRA...

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International Conference on Physics Science and Technology (ICPST)

作者： Li Xu Chen Shu-zong Du De-shun Chen Hua-xin Zhang Dian-hua Northeastern Univ State Key Lab Rolling & Automat Shenyang 110819 Liaoning Peoples R China Gen Elect Co Ltd China Shenyang 110000 Peoples R China Rolling Technol Ctr Liaoning Shenyang 110819 Peoples R China

According to the control principle of pressure AGC, the control thought and control model of BISRA-AGC were analyzed. By changing the external disturbance of rolling force and sampling time, the BISRA-AGC and Dynamic Set AGC were simulated under the conditions that the position control system was ideal by using GUI. Then, the advantages and disadvantages were analyzed combining the results of simulation, and the intrinsic factors were quantitatively analyzed. (C) 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of Garry Lee.

关键词： BISRA-AGC model parameters simulation

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