• Journal of Advanced Marine Engineering and Technology
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• v.38 no.5
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• pp.550-556
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• 2014

In this study, for the control of a single water tank system, a fuzzy-PID controller design technique based on a fuzzy model is investigated. For this purpose, a water tank system is linearized as a number of submodels depending on the operating point, and a fuzzy model is obtained by fuzzy combining. Each submodel is approximated as a first order time delay model, and a PID controller is designed using several existing tuning techniques. Then, through the fuzzy combination of this controller using the same method as that of the fuzzy model, a fuzzy-PID controller is designed. For the proposed technique, a simulation is performed using the fuzzy model of a water tank system, and the validity is examined by comparing its performance with that of a PID controller.

• Korean Journal of Human Ecology
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• v.2 no.1
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• pp.38-51
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• 1999

The purpose of this study was to test the validity of Olson Circumplex Model and Beavers Systems Model related to adolescent adjustment. The 830 subjects were selected from the second grade of middle and high schools and adolescents of Juvenile Judge in the city of Taegu. The survey instruments were FACESIII, SFIII, State-Trait Anxiety Inventory, Depression Scale, and Delinquency Scale. Factor Analysis, Cronbach＇s ${\alpha}$. MANOVA, Scheff＇e test were conducted for the data analysis. The major findings of this study were as follows: 1) Family system classification method on Olson Circumplex Model was partially useful in evaluating anxiety, depression, and delinquency of adolescent. 2) Family system classification method on Beavers Systems Model was partially useful in evaluating anxiety and depression of adolescent. (Korean J Human Ecology 2(1) : 38~51, 1999)

• Journal of the Society of Naval Architects of Korea
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• v.29 no.1
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• pp.191-200
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• 1992

In order to simulate the line heating process which is a three-dimensional transient thermo elastic plastic state, a simple modified strip model is suggested. First attempt is made to verify the validity of the model using a finite element program, and the result gives good agreement with the plate theory where conventional two-dimensional model fails totally.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.1
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• pp.40-46
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• 2012

This paper presents contactless power supply systems using the Valtchev model in transportation systems. The major drawback of contactless systems is that the efficiency is lower than that of contact systems. The coupling coefficient of the contactless transformer is the most influential parameter on the system efficiency. Here, a new computer model for the contactless transfer system developed in the Korea Railroad Research Institute is presented. Also, simulations of the old model and the new model are compared with the prototype measurement to assure the model validity.

• Membrane and Water Treatment
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• v.2 no.4
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• pp.225-237
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• 2011

In this study, response of reversibility of membrane flux during chemically enhanced backwash (CEB) to changes in filtration time, filtration flux and coagulant concentration dosing during ultrafiltration (UF) process was investigated using a regression model. The model was developed via empirical modelling approach using response surface methodology. In developing the model, statistically designed UF experiments were conducted and the results compared with the model output. The results showed that the performance of CEB, evaluated in terms of the reversibility of the membrane flux, depends strongly on the changes in coagulant concentration dosage and the filtration flux. Also the response of the reversibility of membrane flux during CEB is independent of the filtration time. The variance ratio, VR << $F_{value}$ and $R^2$ = 0.98 obtained from the cross-validation experiments indicate perfect agreement of the model output with experimental results and also testify to the validity and suitability of the model to predict reversibility of the membrane flux during CEB in UF operation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.2
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• pp.91-96
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• 2014

An acoustical model for detecting the leak location in a buried gas pipeline has been developed. This model is divided into an experimental model for sound diagnosis, and a theoretical model for sound prediction, which is based on the transfer matrix method, representing the sound pressure and the volume velocity as state variables. The power spectrum is measured by attaching only one microphone to the closed end pipe. It has been shown that the response magnitude of acoustic pressure signals calculated by the acoustical model depends upon the thickness and diameter of a pinhole. The validity for the acoustical model has been verified through a comparison between the measured and calculated results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.1
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• pp.171-177
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• 2002

The viscoelastic dampers are considered to be one of the most efficient means of upgrading existing structures against seismic loads. Generally in the dynamic analysis of a structure with added viscoelastic dampers the internal forces of the dampers are represented by constants that are linearly proportional to displacement and velocity. The purpose of this study is to verify the validity of the linear Kelvin model by comparing the results from the linear analysis with those obtained from the more rigorous nonlinear model such as fractional derivative model. According to the results the structural responses of 1-DOF structure obtained using the linear model are very close to those obtained from nonlinear model. However for multi-D0F structure the difference between the results from both models is enlarged as a results of the assumptions associated with the linear modeling of the viscoelastic dampers.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.217-219
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• 2008

A new experimental model for determining drawbead forces, which modifies the dieface of Nine's experimental model, is introduced and the better validity of the drawbead opening and restraining forces of new model than those of Nine's is demonstrated. While Nine's model considers a blank holding force as one of forming variables, new model excludes it by removing blank holder in the dieface. The comparison of the strains found by FEM simulation of automotive fender draw forming process with those measured in a formed panel recommends the new model for accurate drawbead forces.

• Communications for Statistical Applications and Methods
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• v.29 no.3
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• pp.353-371
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• 2022

This paper analyzes death counts after World War II of several countries to identify and to compare their stochastic structures. The stochastic structures that this paper entertains are three structural time series models, a local level with a random walk model, a fixed local linear trend model and a local linear trend model. The structural time series models assume that a time series can be formulated directly with the unobserved components such as trend, slope, seasonal, cycle and daily effect. Random effect of each unobserved component is characterized by its own stochastic structure and a distribution of its irregular component. The structural time series models use the Kalman filter to estimate unknown parameters of a stochastic model, to predict future data, and to do filtering data. This paper identifies the best-fitted stochastic model for three types of death counts (Female, Male and Total) of each country. Two diagnostic procedures are used to check the validity of fitted models. Three criteria, AIC, BIC and SSPE are used to select the best-fitted valid stochastic model for each type of death counts of each country.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.1008-1019
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• 2020

The purpose of this study is to investigate the effects of social support of students majoring in physical education on their major satisfaction and intention to continue learning, and to prevent dropout of students majoring in physical education in the credit banking system and to find effective management methods. The research tools were verified by confirmatory factor analysis, concentration validity, discriminant validity, average variance extraction (AVE), concept reliability, and Cronbach's coefficient for validity and reliability verification of the research tools. The data processing method was conducted by using IBM SPSS Statistics 21 and IBM AMOS 21 to verify reliability analysis, correlation analysis, and structural equation model (SEM) through frequency analysis, confirmatory factor analysis, concentration validity, discriminant validity, Cronbach's coefficient calculation. The results are as follows. First, the study model was tested and the criteria were met for verifying the suitability of the relationship between social support, major satisfaction and learning persistence intention of the professors majoring in physical education in credit banking system. Second, as a result of the verification of Hypothesis 1, the social support of the professor of the physical education major in the credit banking system has a significant effect on the major satisfaction. The results of the verification of Hypothesis 2 showed that the social support of the professor of the physical education major in the credit banking system affects on the learning persistence. As a result of the verification of Hypothesis 3, it has been shown that major satisfaction has a significant effect on the learning persistence.