• 한국ITS학회 논문지
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• 제7권4호
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• pp.25-35
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• 2008

가변전광표지(VMS: Variable Message Sign)는 도로이용자에게 도로, 기상 및 교통상황, 교통규제 상황에 관한 필요한 정보를 실시간으로 제공함으로써 원활한 교통흐름 및 안전운행을 유도 할 수 있는 지능형교통정보시스템 시설이다. 그 중 이동식가변전광표지(PVMS: Portable Variable Message Signs)는 특정 지점 및 구간에서 발생하는 다양한 이벤트(예: 돌발상황, 도로공사)들에 대해 정보제공 및 능동적 교통제어를 가능하도록 지원하는 장비이다. PVMS에서 표출되는 교통정보는 운전자가 보다 쉽게 이해하고, 눈에 잘 띄고, 적정거리 내에 판독하기 쉬워야 하는 조건을 만족시켜야 한다. 따라서, 운전자의 인적요인(Human Factor) 특성을 고려한 PVMS의 설치 및 메시지 운영은 쾌적성 및 안전성 향상을 위한 필수조건이라 할 수 있다. 본 연구에서는 운전경력, 성별, 연령 등의 인적요인이 PVMS를 통해 제공되는 정보처리에 미치는 영향을 메시지 판독거리를 중심으로 분석하였다. 본 연구 결과는 향후 국내 운전자 반응특성을 고려 한 VMS 설치 및 운영을 위 한 기초 연구자료로서 활용 될 것으로 기대된다.

• International Journal of Reliability and Applications
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• 제1권2호
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• pp.155-165
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• 2000

In this paper, we propose some estimators of Kullback- Leibler Information functions using the data from three step stress accelerated life tests. This acceleration model is assumed to be a tampered random variable model. Some asymptotic properties of proposed estimators are proved. Simulations are performed for comparing the small sample properties of the proposed estimators under use condition of accelerated life test.

• Journal of the Korean Data and Information Science Society
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• 제8권2호
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• pp.271-276
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• 1997

A dynamic discount approach is proposed for the estimation of the Poisson parameter and the forecasting of the Poisson random variable, where the parameter of the Poisson distribution varies over time intervals. The recursive estimation procedure of the Poisson parameter is provided. Also the forecasted distribution of the Poisson random variable in the next time interval based on the information gathered until the current time interval is provided.

• Journal of the Korean Data and Information Science Society
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• 제24권3호
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• pp.659-667
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• 2013

If the regression model or the propensity model is correct, the unbiasedness of the estimator using doubly robust imputation can be guaranteed. Using a neural network instead of a logistic regression model for the propensity model, the estimators using doubly robust imputation are approximately unbiased even though both assumed models fail. We also propose a doubly robust estimator of ratio form using population information of an auxiliary variable. We prove some properties of proposed theory by restricted simulations.

• Communications for Statistical Applications and Methods
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• 제16권1호
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• pp.143-155
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• 2009

Best subset selection procedure based on mutual information (MI) between a set of explanatory variables and a dependent class variable is suggested. Derivation of multivariate MI is based on normal mixtures. Several types of normal mixtures are proposed. Also a best subset selection algorithm is proposed. Four real data sets are employed to demonstrate the efficiency of the proposals.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(1)
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• pp.153-156
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• 2002

An adaptive predistorr is proposed to compensate for the nonlinear distortion of a high power amplifier (HPA) in 16 QAM system. It fumed out that the proposed predistorter using a variable step-size least mean square (VSSLMS) algorithm is stable and can reduce the Total Distortion (TD) to 0. 1dB at the HPA output backoff=0.0 dB.

• 응용통계연구
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• 제25권3호
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• pp.471-483
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• 2012

One of the most important problems in cluster analysis is the selection of variables that truly define cluster structure, while eliminating noisy variables that mask such structure. Brusco and Cradit (2001) present VS-KM(variable-selection heuristic for K-means clustering) procedure for selecting true variables for K-means clustering based on adjusted Rand index. This procedure starts with the fixed number of clusters in K-means and adds variables sequentially based on an adjusted Rand index. This paper presents an updated procedure combining the VS-KM with the automated K-means procedure provided by Kim (2009). This automated variable selection procedure for K-means clustering calculates the cluster number and initial cluster center whenever new variable is added and adds a variable based on adjusted Rand index. Simulation result indicates that the proposed procedure is very effective at selecting true variables and at eliminating noisy variables. Implemented program using R can be obtained on the website "http://faculty.knou.ac.kr/sskim/nvarkm.r and vnvarkm.r".

• 정보처리학회논문지A
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• 제8A권1호
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• pp.56-62
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• 2001

This paper presents a neural network based variable structure control scheme for nonlinear systems. In this scheme, a set of local variable structure control laws are designed on the basis of the linear models about preselected representative points which cover the range of the system operation of interest. From the combination of the set of local variable structure control laws, neural networks infer the approximate control input in between the operating points. The neural network based variable structure control alleviates the effects of model uncertainties, which cannot be compensated by the control techniques using feedback linearization. It also relaxes the discontinuity in the system’s behavior that appears when the control schemes based on the family of the linear models are applied to nonlinear systems. Simulation results of a ball and beam system, to which feedback linearization cannot be applied, demonstrate the feasibility of the proposed method.

• 대한전기학회논문지
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• 제40권7호
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• pp.706-717
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• 1991

In order to remove the assumption of full state availability which is one of the major difficulties with the practical realization of variable structure control systems,a new switching function with a dynamic structure is proposed. And the control performances of the output feedback variable structure control systems with the dynamic switching function are evaluated through simulation studies. The proposed dynamic switching function is driven by small number of measured output and input variables while conventional static switching function requires full state information. Therefore, the proposition of the dynamic swiching function makes practical implementation of output feedback variable structure control scheme possible for the systems with unmeasurable state variables, high order systems and large scale systems that the conventional variable structure control schemes with static switching function cannot be applied. In the variable structure control systems with the dynamic switching function, desired control performance can be guaranteed by proper choice of design parameters such as poles of switching function dynamic equation and switching control gains even though small number of measured output and input variables are provided as shown in simulation resuls.

• 대한가정학회지
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• 제36권5호
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• pp.75-88
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• 1998

The purpose of this study is to investigate (1) the level of childrens' concern and behavior on the environmental preservation, (2) the influential factors related to the two dependent variables above mentioned. The subjects were 286 childrens, in October, 1997, in kwangju. The data obtained were analyzed by Mean, Person's correlation, Stepwise Regression and Path Analysis. The major findings were as follows: 1) The general tendency of the childrens' concern and behavior on the environmental preservation was over the average level. 2) According to the background variables(ie: environment information contracting time, family cohesion and adaptability, biospheric orientation, egoistic orientation), the childrens' concern on the environment was significantly different. 3) According to (1) the background variables(ie: environment information contracting time, family cohesion and adaptability, concern on the environment, biospheric orientation), (2) intermediated variable(ie: concern on the environment), the childrnes' behavior on the environmental preservation was significantly different. 4) The indirect variable of the positive influence for childrnds' behavior on the environment, environment information contracting time. The indirect variable of the negative influence for childrens' the environmental behavior was egoistic orientation.