• 한국통계학회:학술대회논문집
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• 한국통계학회 2005년도 춘계 학술발표회 논문집
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• pp.233-238
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• 2005

S${\"{a}}$rndal (1996) and Knottnerus (2003) had a critical look at the well known variance estimator of Sen (1953) and Yates and Grundy (1953) in probability proportional to size sampling. In this paper, we point out that although their approaches can avoid the difficulties in variance estimation with respect to the joint probabilities, there exist the disadvantages in practice. Also, we describe a sampling procedure available in statistical software that are useful for the variance estimation.

• Communications for Statistical Applications and Methods
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• 제12권1호
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• pp.181-189
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• 2005

This paper suggest a method of inclusion probability proportional to size sampling that provides a non-negative and stable variance estimator. The sampling procedure is quite simple and flexible since a sampling design is easily obtained using mathematical programming. This scheme appears to be preferable to Nigam, Kumar and Gupta's (1984) method which uses a balanced incomplete block designs. A comparison is made with their method through an example in the literature.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2004년도 춘계학술대회
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• pp.39-50
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• 2004

The decision tree approach is most useful in classification problems and to divide the search space into rectangular regions. Decision tree algorithms are used extensively for data mining in many domains such as retail target marketing, fraud dection, data reduction and variable screening, category merging, etc. CHAID(Chi-square Automatic Interaction Detector) uses the chi-squired statistic to determine splitting and is an exploratory method used to study the relationship between a dependent variable and a series of predictor variables. In this paper we propose CHAID algorithm by cube-based proportional sampling and explore CHAID algorithm in view of accuracy and speed by the number of variables.

• Journal of the Korean Data and Information Science Society
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• 제15권4호
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• pp.803-816
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• 2004

The decision tree approach is most useful in classification problems and to divide the search space into rectangular regions. Decision tree algorithms are used extensively for data mining in many domains such as retail target marketing, fraud dection, data reduction and variable screening, category merging, etc. CHAID uses the chi-squired statistic to determine splitting and is an exploratory method used to study the relationship between a dependent variable and a series of predictor variables. In this paper we propose CHAID algorithm by cube-based proportional sampling and explore CHAID algorithm in view of accuracy and speed by the number of variables.

• 전자공학회논문지SC
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• 제44권6호
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• pp.21-28
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• 2007

Mutiresolution proportional-integral-derivative(MRPID) 제어기는 웨이브렛 기반의 다해상도 응답을 이용해서 에러 신호에 포함되어 있는 잡음과 외란을 제거하는 필터 역할을 해준다. 다해상도 응답의 특징상 샘플링 주파수가 높을 경우 상대적으로 고주파성분이 남아있음으로 인해 응답속도가 떨어지는 대신에 오버슈트가 제거되고, 낮을 경우 신호 성분이 제거되므로 인해 응답속도가 향상되지만 오버슈트가 증가 되는 결과를 보였다. 본 논문에서는 proportional-integral-derivative(PID) 제어기와 MRPID 제어기의 응답을 이용한 샘플링 주파수를 설정하는 기법과, MRPID 제어기의 특성을 고려한 파라미터 설정기법을 제안한다. 모의실험을 통해서 제안된 기법의 타당성을 검증하였다.

• Communications for Statistical Applications and Methods
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• 제19권6호
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• pp.751-759
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• 2012

This paper proposes an alternative stratified randomized response model based on the model of Singh and Joarder (1997). It is shown numerically that the proposed stratified randomized response model is more efficient than Hong et al. (1994) (under proportional allocation) and Kim and Warde (2004) (under optimum allocation).

• Journal of the Korean Statistical Society
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• 제31권4호
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• pp.509-518
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• 2002

This paper is concerned with semiparametric Bayesian analysis of the proportional intensity regression model of the Poisson process for multiple event time data. A nonparametric prior distribution is put on the baseline cumulative intensity function and a usual parametric prior distribution is given to the regression parameter. Also we allow heterogeneity among the intensity processes in different subjects by using unobserved random frailty components. Gibbs sampling approach with the Metropolis-Hastings algorithm is used to explore the posterior distributions. Finally, the results are applied to a real data set.

• 응용통계연구
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• 제19권1호
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• pp.69-80
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• 2006

본 연구에서는 매우 민감한 조사에서 모집단이 집락의 크기가 서로 다른 여러 개의 집락으로 구성되어 있을 때, 집락의 크기에 비례하게 추출확률을 부여하는 확률비례추출법(probability proportional to size : pps)을 이용한 확률화응답기법을 제안하고자 한다. 민감한 속성에 대한 모수의 추정치와 분산 및 분산추정량을 구하여 이론적 체계를 구축하고, 확률비례추출법에 의한 확률화응답기법과 등확률 2단계 추출법에 의한 확률화응답기법의 효율성을 비교해 보고자 한다. 또한, 실제조사를 통해 제안한 확률비례추출법에 의한 확률화응답기법에 대한 실용화의 타당성을 검토하고자 한다.

• Structural Engineering and Mechanics
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• 제32권1호
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• pp.55-69
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• 2009

A quasi ideal importance sampling simulation method combined in the conditional expectation is proposed for the structural reliability estimation. The quasi ideal importance sampling joint probability density function (p.d.f.) is so composed on the basis of the ideal importance sampling concept as to be proportional to the conditional failure probability multiplied by the p.d.f. of the sampling variables. The respective marginal p.d.f.s of the ideal importance sampling joint p.d.f. are determined numerically by the simulations and partly by the piecewise integrations. The quasi ideal importance sampling simulations combined in the conditional expectation are executed to estimate the failure probabilities of structures with multiple failure surfaces and it is shown that the proposed method gives accurate estimations efficiently.

• 대한토목학회논문집
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• 제26권3B호
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• pp.291-300
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• 2006

본 연구에서는 통계를 이용한 경안천유역의 최적 수질 측정망 구성이 제안된다. 분석을 위해서 필요한 수질 데이터는 QUAL2E 모형을 이용하여 모의하였으며, 경안천 유역의 2000년도 3월부터 11월까지의 월 평균자료를 이용하였다. QUAL2E 모형을 구축하는데 필요한 수리 매개변수는HEC-RAS모형을 이용하여 추정하였다. 수질매개변수의 경우 월평균 실측자료를 바탕으로 1차 신뢰성 분석(FORA)를 이용하여 민감도 분석을 실시하여 수질항목별로 민감하지 않은 매개변수를 제외한 후 보정이 이루어진다. QUAL2E 모형의 모의 결과를 바탕으로 크리깅 기법과 Branch and Boundary Method를 이용하여 평수량 일때와 갈수량 일때로 구분하여 관측지점의 개수와 위치가 결정된다. 또한 선정된 지점을 기준으로 proportional sampling method(비례표본추출법)를 이용하여 각각의 지점별 측정 빈도가 제시된다.