• Title/Summary/Keyword: 함수계수모형

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Development of Stochastic Decision Model for Estimation of Optimal In-depth Inspection Period of Harbor Structures (항만 구조물의 최적 정밀점검 시기 추정을 위한 추계학적 결정모형의 개발)

  • Lee, Cheol-Eung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.28 no.2
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    • pp.63-72
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    • 2016
  • An expected-discounted cost model based on RRP(Renewal Reward Process), referred to as a stochastic decision model, has been developed to estimate the optimal period of in-depth inspection which is one of critical issues in the life-cycle maintenance management of harbor structures such as rubble-mound breakwaters. A mathematical model, which is a function of the probability distribution of the service-life, has been formulated by simultaneously adopting PIM(Periodic Inspection and Maintenance) and CBIM(Condition-Based Inspection and Maintenance) policies so as to resolve limitations of other models, also all the costs in the model associated with monitoring and repair have been discounted with time. From both an analytical solution derived in this paper under the condition in which a failure rate function is a constant and the sensitivity analyses for the variety of different distribution functions and conditions, it has been confirmed that the present solution is more versatile than the existing solution suggested in a very simplified setting. Additionally, even in that case which the probability distribution of the service-life is estimated through the stochastic process, the present model is of course also well suited to interpret the nonlinearity of deterioration process. In particular, a MCS(Monte-Carlo Simulation)-based sample path method has been used to evaluate the parameters of a damage intensity function in stochastic process. Finally, the present stochastic decision model can satisfactorily be applied to armor units of rubble mound breakwaters. The optimal periods of in-depth inspection of rubble-mound breakwaters can be determined by minimizing the expected total cost rate with respect to the behavioral feature of damage process, the level of serviceability limit, and the consequence of that structure.

Seepage Behavior by Artificial Rainfall in Weathered Granite Model Slope (화강풍화토 모형사면의 인공강우 침투거동 해석)

  • Lee, Kumsung;Han, Heuisoo;Chang, Donghun;Yoon, Donggu
    • Journal of the Korean GEO-environmental Society
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    • v.14 no.12
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    • pp.5-12
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    • 2013
  • In this study, weathered granite model tests were performed to investigate the variation of volumetric water content and matric suction by the adsorption and desorption processes of artificial rainfall. It has been compared with numerical analysis in unsaturated condition. As the results, the behaviors of volumetric water content and matric suction were distinguished by the seepage distance separated into higher, middle and lower area, and the drainage layer located at the bottom of the experimental device. In the adsorption process, the instantaneously large change of matric suction and water content were related to the increase of permeability in soil. However, in the desorption process, the change of matric suction and water content were gradually small because of the decrease of permeability. The volumetric water content and matric suction showed the difference according to the seepage distance, however the typical characteristic curves were made by the adsorption and desorption processes.

Coefficient change of objective function not change to the basic vector make a optimum solution (최적해를 이루는 기저벡터가 변화를 초래하지 않는 목적함수계수의 변화)

  • 송필준;김정숙
    • Journal of Korea Society of Industrial Information Systems
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    • v.7 no.1
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    • pp.58-65
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    • 2002
  • When we estimate the optimal solution satisfy the objective function and subjective equation in the integer programming, The optimal solution of the objective function Z is decided by the positive integer at extreme point or revised extreme point in the convex set. The convex set is made up the linear subjective equation. The purpose of the paper is thus to establish a stepwise optimization in the integer programming model by estimating the variation △C/sub j/ of the constant term C/sub j/ in the linear objective function, after an application of the modified Branch & Bound method.

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Comments on the regression coefficients (다중회귀에서 회귀계수 추정량의 특성)

  • Kahng, Myung-Wook
    • The Korean Journal of Applied Statistics
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    • v.34 no.4
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    • pp.589-597
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    • 2021
  • In simple and multiple regression, there is a difference in the meaning of regression coefficients, and not only are the estimates of regression coefficients different, but they also have different signs. Understanding the relative contribution of explanatory variables in a regression model is an important part of regression analysis. In a standardized regression model, the regression coefficient can be interpreted as the change in the response variable with respect to the standard deviation when the explanatory variable increases by the standard deviation in a situation where the values of the explanatory variables other than the corresponding explanatory variable are fixed. However, the size of the standardized regression coefficient is not a proper measure of the relative importance of each explanatory variable. In this paper, the estimator of the regression coefficient in multiple regression is expressed as a function of the correlation coefficient and the coefficient of determination. Furthermore, it is considered in terms of the effect of an additional explanatory variable and additional increase in the coefficient of determination. We also explore the relationship between estimates of regression coefficients and correlation coefficients in various plots. These results are specifically applied when there are two explanatory variables.

Time series analysis for the amount of medicine from the Korea Consumer Agency (한국 소비자원 의료분야 처리금액에 대한 시계열 분석)

  • Hee Song Kang;Sukhui Kwon;SungDuck Lee
    • The Korean Journal of Applied Statistics
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    • v.36 no.1
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    • pp.21-32
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    • 2023
  • The amount of money processed in medicine from the Korea Consumer Agency was studied by the various time series models. The medical data set from the Korea Consumer Agency were consisted of counseling, damage relief and conciliation. For the analysis of time series, autoregressive moving average model, vector autoregressive model and the transfer function model were used. We considered the stationarity and cross correlation function for the identification and fitting. As a result, the transfer function model showed a better prediction. Whereas, the vector autoregressive model also provided good information for the degree and duration of the influence of variables.

A study on fuzzy goals of system with hierarchical structure (계층적구조를 갖는 시스템의 FUZZY GOALS에 관한 연구)

  • 박주녕;송서일
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.12 no.20
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    • pp.97-104
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    • 1989
  • In this thesis, each objective functions with hierarchical system Bi-level linear programming (BLPP) Problem applications to fuzzy set theory conducted multiple objective programming problem. Using linear fuzzy membership functions make a change typical BLPP and presents modified method turn to account established BLPP method, presents operation results lead to example. Fuzzy Bi-level linear programming problem (FBLPP) can be natural describe realities of life then BLPP.

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Numerical Analysis of Subsurface Flow in a Hillslope (자연 구릉지에서 지표하 흐름의 수치해석)

  • 최은호;남선우
    • Water for future
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    • v.24 no.1
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    • pp.109-117
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    • 1991
  • The governing equation of flow in porous media is developed on the bases of the continuity equation of fluid for transient flow through a saturated-unsaturated zone, and substitution of Darcy's law. The numerical solutions are obtained by finite element method based on the Galerkin principles weighted residuals. The analysis are carried out by using the unsteady storm data observed and rainfall intensities which are obtained by using the rainfall excess model in considering of the initial losses. The functional relationships between the hydraulic conductivity, capillary pressure head and volumetric water content are applied to the flow of water through unsaturated soil varied with changes of water content.

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A statistical analysis of the fat mass experimental data using random coefficient model (변량계수모형을 이용한 체지방 실험자료에 관한 통계적 분석)

  • Jo, Jin-Nam
    • Journal of the Korean Data and Information Science Society
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    • v.22 no.2
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    • pp.287-296
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    • 2011
  • Thirty six female students participated in the experiment of the fat mass weight loss. they kept diary for foods they ate every day, took a picture of the foods, transmitted the picture to the experimenter by the camera phone, and consulted him about fat mass loss once a week for 8 weeks period. Fat mass weight and its related factors of the students had been measured repeatedly every week during 8 weeks, The repeated measurement data were used for applying various random coefficient models. And hence optimal random coefficient model was selected. From the optimal model, the baseline, body mass index, diastolic blood pressure, total cholesterol and time of the fixed factors were very significant. The fixed quadratic time effect existed. The variance components corresponding to the subject effect, linear time effect of the random coefficients were all positive. Thus random coefficients up to the linear terms were considered as the optimal model. The treatment effect reduced the weight loss to an average of 2.1kg at the end of the period.

Comparative Evaluation of Determination Methods of Vertical Eddy Viscosity for Computation of Wind-Induced Flows (풍성류 계산을 위한 연직 와점성계수 산정방법의 비교평가)

  • 정태성;이길성;오병철
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.6 no.3
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    • pp.205-215
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    • 1994
  • A 3-dimensional numerical model of wind-induced flows has been established. and comparative evaluation of determination methods of vertical eddy viscosity has been performed. The model uses turbulence models to calculate vertical eddy viscosity. The examined methods arp 0-equation model of functional form, 1-equation model of turbulence kinetic energy, and two 2-equation models ($textsc{k}$-$\varepsilon$ and $textsc{k}$-ι models). The evaluation includes the verification tests against experimental data for wind-driven current On a closed one-dimensional channel and a recirculating one-dimensional channel. Comparative study of turbulence models has shown that the proper distribution of turbulence scale is parabolic and the eddy viscosity is depending strongly on mixing depth due to wind.

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A Study on statistical inference on IL-2 titer (IL-2 역가의 통계적 추정에 관한 연구)

  • 박래현;박석영;이석훈
    • The Korean Journal of Applied Statistics
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    • v.2 no.2
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    • pp.27-35
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    • 1989
  • This article deals with statistical inference on Interleukin-2 titer of which the clinical applications to cancer immunotherapy and some immunodeficiency diseases have been widely tried. A Linear model and the Bayesian approach are used to explain the bioassay which performs the measurements of IL-2 activity from an patient and an inference procedure including confidence intervals for the IL-2 titer of the patient through comparision with the Standard IL-2 is suggested and a real case of example is illustrated.

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