• Title/Summary/Keyword: Parameter

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The Parameter Estimation of WASP Model for Water Quality Prediction (수질예측을 위한 WASP7 모형 매개변수의 추정)

  • Ahn, Seung-Seop;Seo, Myung-Joon;Park, Ro-Sam;Jeong, Khang-Ok
    • Journal of Environmental Science International
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    • v.16 no.5
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    • pp.623-632
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    • 2007
  • The objective of this study is analysis of Andong-Dam lake water quality with water quality model. Model parameters of the WASP applied to Lake Andong-Dam were estimated. The methodology is based on grouping water quality constituents and relevant parameters and successively estimating parameters by a trial-and-error procedure. Water qualify system for modeling consisted of BOD, DO, T-N, T-P. The results of water quality modelling using WASP. T-N was maximum affected by K71C(Organic nitrogen mineralization rate) parameter. T-P was maximum affected by K83C(Dissolved organic phosphorus mineralization) parameter, and It did not show a difference almost from the parameter of others and it omitted. BOD was maximum affected by Temperature parameter, it was visible of the reaction due to the KDC(Deoxygenation rate) in afterwords, and it did not show a difference from the parameter of others and it omitted. DO was maximum affect by Temperature parameter, and It did not show a difference almost from the parameter of others and it omitted. The parameter which it presumes from the this study uses a water quality modeling and Actual value and the result with which it compares, error rate the parameter presumption which is appropriate with 1% interior and exterior is investigated, It will reach and it uses and it will be able to apply to the suitable parameter in water quality modelling of the objective area which can be feeded by it becomes.

Tracking control of variable stiffness hysteretic-systems using linear-parameter-varying gain-scheduled controller

  • Pasala, D.T.R.;Nagarajaiah, S.;Grigoriadis, K.M.
    • Smart Structures and Systems
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    • v.9 no.4
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    • pp.373-392
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    • 2012
  • Tracking control of systems with variable stiffness hysteresis using a gain-scheduled (GS) controller is developed in this paper. Variable stiffness hysteretic system is represented as quasi linear parameter dependent system with known bounds on parameters. Assuming that the parameters can be measured or estimated in real-time, a GS controller that ensures the performance and the stability of the closed-loop system over the entire range of parameter variation is designed. The proposed method is implemented on a spring-mass system which consists of a semi-active independently variable stiffness (SAIVS) device that exhibits hysteresis and precisely controllable stiffness change in real-time. The SAIVS system with variable stiffness hysteresis is represented as quasi linear parameter varying (LPV) system with two parameters: linear time-varying stiffness (parameter with slow variation rate) and stiffness of the friction-hysteresis (parameter with high variation rate). The proposed LPV-GS controller can accommodate both slow and fast varying parameter, which was not possible with the controllers proposed in the prior studies. Effectiveness of the proposed controller is demonstrated by comparing the results with a fixed robust $\mathcal{H}_{\infty}$ controller that assumes the parameter variation as an uncertainty. Superior performance of the LPV-GS over the robust $\mathcal{H}_{\infty}$ controller is demonstrated for varying stiffness hysteresis of SAIVS device and for different ranges of tracking displacements. The LPV-GS controller is capable of adapting to any parameter changes whereas the $\mathcal{H}_{\infty}$ controller is effective only when the system parameters are in the vicinity of the nominal plant parameters for which the controller is designed. The robust $\mathcal{H}_{\infty}$ controller becomes unstable under large parameter variations but the LPV-GS will ensure stability and guarantee the desired closed-loop performance.

Simulation Input Modeling : Sample Size Determination for Parameter Estimation of Probability Distributions (시뮬레이션 입력 모형화 : 확률분포 모수 추정을 위한 표본크기 결정)

  • Park Sung-Min
    • Journal of the Korean Operations Research and Management Science Society
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    • v.31 no.1
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    • pp.15-24
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    • 2006
  • In simulation input modeling, it is important to identify a probability distribution to represent the input process of interest. In this paper, an appropriate sample size is determined for parameter estimation associated with some typical probability distributions frequently encountered in simulation input modeling. For this purpose, a statistical measure is proposed to evaluate the effect of sample size on the precision as well as the accuracy related to the parameter estimation, square rooted mean square error to parameter ratio. Based on this evaluation measure, this sample size effect can be not only analyzed dimensionlessly against parameter's unit but also scaled regardless of parameter's magnitude. In the Monte Carlo simulation experiments, three continuous and one discrete probability distributions are investigated such as ; 1) exponential ; 2) gamma ; 3) normal ; and 4) poisson. The parameter's magnitudes tested are designed in order to represent distinct skewness respectively. Results show that ; 1) the evaluation measure drastically improves until the sample size approaches around 200 ; 2) up to the sample size about 400, the improvement continues but becomes ineffective ; and 3) plots of the evaluation measure have a similar plateau pattern beyond the sample size of 400. A case study with real datasets presents for verifying the experimental results.

Weighted Parameter Analysis of L1 Minimization for Occlusion Problem in Visual Tracking (영상 추적의 Occlusion 문제 해결을 위한 L1 Minimization의 Weighted Parameter 분석)

  • Wibowo, Suryo Adhi;Jang, Eunseok;Lee, Hansoo;Kim, Sungshin
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.05a
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    • pp.101-103
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    • 2016
  • Recently, the target object can be represented as sparse coefficient vector in visual tracking. Due to this reason, exploitation of the compressibility in the transform domain by using L1 minimization is needed. Further, L1 minimization is proposed to handle the occlusion problem in visual tracking, since tracking failures mostly are caused by occlusion. Furthermore, there is a weighted parameter in L1 minimization that influences the result of this minimization. In this paper, this parameter is analyzed for occlusion problem in visual tracking. Several coefficients that derived from median value of the target object, mean value of the arget object, the standard deviation of the target object are, 0, 0.1, and 0.01 are used as weighted parameter of L1 minimization. Based on the experimental results, the value which is equal to 0.1 is suggested as weighted parameter of L1 minimization, due to achieved the best result of success rate and precision performance parameter. Both of these performance parameters are based on one pass evaluation (OPE).

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Calculation of $G_1$ for unidirectional laminated composites by using the two parameter technique (이항변수방법을 사용한 단일방향 적층복합재의 전단모드 에너지방출률 계산)

  • Rhee, Gyeong-Yeop
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.1
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    • pp.164-172
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    • 1997
  • Two parameter technique that uses far-field stress and displacement distributions was applied to composite laminates in order to calculate mode II energy release rate, $G_{II}$ . The $G_{II}$ calculated by two parameter technique was compared with that calculated from the crack closure method to inspect the effectiveness of two parameter technique. Sensitivity study of two parameter technique to the crack extension size was also performed. The results showed that both methods produced comparable $G_{II}$ results. In particular, it was found that although the crack closure method was affected by the crack extension size, the two parameter technique was less affected by the crack extension size.

Bayesian Parameter Estimation of the Four-Parameter Gamma Distribution

  • Oh, Mi-Ra;Kim, Kyung-Sook;Cho, Wan-Hyun;Son, Young-Sook
    • Communications for Statistical Applications and Methods
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    • v.14 no.1
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    • pp.255-266
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    • 2007
  • A Bayesian estimation of the four-parameter gamma distribution is considered under the noninformative prior. The Bayesian estimators are obtained by the Gibbs sampling. The generation of the shape/power parameter and the power parameter in the Gibbs sampler is implemented using the adaptive rejection sampling algorithm of Gilks and Wild (1992). Also, the location parameter is generated using the adaptive rejection Metropolis sampling algorithm of Gilks, Best and Tan (1995). Finally, the simulation result is presented.

Preliminary Hull Form Design Using Form Parameter Method and Neural Networks (Form Parameter 방법과 신경망을 이용한 초기 선형 설계)

  • Park, Won;Shin, Sung-Chul;Kim, Soo-Young;Jang, Hyeon-Jae
    • Journal of Ocean Engineering and Technology
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    • v.13 no.4 s.35
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    • pp.174-181
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    • 1999
  • A form parameter method compounds the form parameters which define the hull geometric characteristics. This method can transform a hull form by changing the form parameters. The form parameter method is a hull define method without utilization of mother ships. However it is difficult to determine these form parameters. Thus, we are complemented the form parameter method using the neural networks. It is found that the form parameter method using the neural networks is efficient in hull form design by consideration of application examples.

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Development of Fretting Fatigue Parameter (접촉피로 파라미터의 개발)

  • Lee, Hyuk-Jae
    • Journal of the Korea Institute of Military Science and Technology
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    • v.14 no.1
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    • pp.92-99
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    • 2011
  • In this study, new multi-axial, critical plane based, fretting fatigue crack initiation parameter is developed by the addition of a new term into the Modified Shear Stress Range(MSSR) parameter. The newly developed parameter (MSSR') is then used to evaluate fretting fatigue life of titanium alloy, Ti-6A1-4V with various contact conditions. Finite element analysis is also used in order to obtain stress distribution on the contact surface during fretting fatigue test, which is then used for the calculation of fretting fatigue parameter. The MSSR' parameter shows better performance in predicting fretting fatigue lives from the conventional fatigue data, and less scattering within fretting fatigue data with different contact geometries.

Estimation of Defect Clustering Parameter Using Markov Chain Monte Carlo (Markov Chain Monte Carlo를 이용한 반도체 결함 클러스터링 파라미터의 추정)

  • Ha, Chung-Hun;Chang, Jun-Hyun;Kim, Joon-Hyun
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.32 no.3
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    • pp.99-109
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    • 2009
  • Negative binomial yield model for semiconductor manufacturing consists of two parameters which are the average number of defects per die and the clustering parameter. Estimating the clustering parameter is quite complex because the parameter has not clear closed form. In this paper, a Bayesian approach using Markov Chain Monte Carlo is proposed to estimate the clustering parameter. To find an appropriate estimation method for the clustering parameter, two typical estimators, the method of moments estimator and the maximum likelihood estimator, and the proposed Bayesian estimator are compared with respect to the mean absolute deviation between the real yield and the estimated yield. Experimental results show that both the proposed Bayesian estimator and the maximum likelihood estimator have excellent performance and the choice of method depends on the purpose of use.

Parameter resetting in adult second language acquisition (성인의 제2 언어 습득에 있어서 매개변수 재고정)

  • Kim, Hak-Soo
    • English Language & Literature Teaching
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    • no.5
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    • pp.219-247
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    • 1999
  • The purpose of this paper is to examine how Korean learners of English reset the "prodrop" parameter of Korean into "non-prodrop" parameter of English in the process of English acquisition. An experiment was conducted to 45 Korean learners of English on the prodrop phenomenon, namely on the null referential or null nonreferential subject, and subject-verb agreement by way of grammatical judgment. The results of the experiment are as follows: First, L2 learners follow the parameter of L1, and then reset the parameter of L2 regardless of the parameter of L1 as their L2 abilities advance. Thus, this study provides further support for the hypothesis that universal grammar is available via L1. Second, the referential subject is, at first, easier to acquire than nonreferential subject, and the triggering fact for the switch from [+prodrop] to [-prodrop] was the use of nonreferential subjects. Third, 3rd person agreement has no connection with the acquisition of the prodrop parameter as a result of subject-verb agreement. Therefore, these results indicate that verb agreement is not a trigger for the recognition of the obligatory subject.

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