• Water for future
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• v.28 no.4
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• pp.185-194
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• 1995

The objective of this study is to explore scale problem and to analyze the relations between scale and geomorphologic parameters of the rainfall-runoff model. Generally, measurement and calculation of geomorphologic parameters rely on and are sensitive to the resolution of source information available. Therefore, rainfall-runoff models using geomorphologic parameters should take account of the effects of the map scale used in their development. The derived rainfall-runoff model considering scale problem in this research is the GIUH type model, that is a basin IUH consisting of the channel network response and hillslope response. The cannel network response is computed by means of the diffusion analogy transformed from linearized St. Venant equation and hillslope response is calculated by 2-parameter gamma distribution function. Representing geomorphologic structure of the channel network and initial distribution of its response is width function. This width function is derived by fractal theory and Melton's law to consider scale problems and is weighted by the source location function (SLF) proposed in this research to increase the applicability.

• The Korean Journal of Applied Statistics
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• v.28 no.6
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• pp.1113-1120
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• 2015

We propose a multi-proportions randomized response model by stratified simple random sampling for surveys of sensitive issues of a polychotomous population composed of several stratum. We also systemize a theoretical validity to apply multi-proportions randomized response model (Abul-Ela et al.' model, Eriksson's model) to stratified simple random sampling and derive the estimate and its dispersion matrix of the proportion of sensitive characteristic of population using the suggested model. Two types of sample allocations (proportional allocation and optimum allocation) are considered under the fixed cost. In efficiency, the Eriksson's model by stratified sampling are compared to the Abul-Ela et al.' model.

• Geophysics and Geophysical Exploration
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• v.5 no.2
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• pp.99-107
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• 2002

An analytical forward modeling algorithm was developed for the efficient application to the geotechnical engineering in SASW (Spectral Analysis of Surface Waves) method. for the theoretical dispersion curve, the finite difference method using motion stress vector, which was proposed by Aki and Richards, was employed and verified with two earth models. For the stable and fast calculation, it was found that the model size depending on the frequency range is suitable $1.5\~2$ times bigger than the wavelength.

• Journal of the Korean Data and Information Science Society
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• v.23 no.4
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• pp.627-641
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• 2012

We consider a model estimation and model selection methods for the multi-way contingency table data with non-response or missing values. We also consider hierarchical Bayesian model in order to handle a boundary solution problem that can happen in the maximum likelihood estimation under non-ignorable non-response model and we deal with a model selection method to find the best model for the data. We utilized Bayes factors to handle model selection problem under Bayesian approach. We applied proposed method to the pre-election survey for the 2004 Korean National Assembly race. As a result, we got the non-ignorable non-response model was favored and the variable of voting intention was most suitable.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.955-963
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• 2006

As the geometrical characteristic of the curved bridge, the seismic response of curved bridges are different from straight bridges. This study analyzed the seismic response of the curved bridges considering diverse factors such as radius of curvature, direction of seismic load and support condition. The improved simple modeling of the curved bridge for seismic analysis is proposed, and it is compared with the detail modeling in order to verify the simple modeling. Three simply supported curved bridges and six 3-span continuous bridges are selected for seismic analysis. The behavior of curved bridges are evaluated in terms of the displacement and the force at supports and piers under seismic load applied in various directions. The results of this study show that upward reaction force may appear in simply supported curved bridge under seismic load. And continuous curved bridges are affected by the direction of the seismic load.

• The Korean Journal of Applied Statistics
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• v.34 no.5
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• pp.685-696
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• 2021

The Korean Economically Active Population Survey (KEAPS) is a national survey that produces employment-related statistics. The main purpose of the survey is to find out the economic activity status (employed/ unemployed/ non-employed) of the people. KEAPS has a unique characteristics caused by the survey method. In this study, through understanding of structural non-response and utilization of past data, we would like to present an improved imputation model. The performance of the proposed model is compared with the existing model through simulation. The performance of the imputation models is evaluated based on the degree of mathing/nonmatching rates. For this, we employ the KEAPS data in November 2019. For the randomly selected ones among the total 59,996 respondents, the six explanatory variables, which are critical in determining the economic activity states, are treated as non-response. The proposed model includes industry variable and job status variable in addition to the explanatory variables used in the precedent research. This is based on the linkage and utilization of past data. The simulation results confirm that the proposed model with additional variables outperforms the existing model in the precedent research. In addition, we consider various scenarios for the number of non-responders by the economic activity status.

• The Korean Journal of Applied Statistics
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• v.6 no.1
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• pp.53-66
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• 1993

A Bayesian approach is suggested to the multi-proportions randomized response model. O'Hagan's (1987) Bayes linear estimator is extended to the inference of unrelated question-type randomized response model. Also some numerical comparisons are provided to show the performance of the Bayes linear estimator under the Dirichlet prior.

• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.57-59
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• 2007

정보보호시스템 평가수요의 예측은 예측된 평가수요를 근거로 적극적인 평가서비스를 제공하기 위하여 필요하다. 평가수요예측을 하기위하여 일반적으로 설문조사를 이용하지만 무응답 및 불성실한 응답으로 인하여 설문응답 자료만으로 평가수요를 예측하기에는 부족하다. 따라서 설문조사의 평가수요를 보정할 수 있는 모형이 필요하다. 본 논문에서는 설문조사를 통하여 예측 할 수 있는 직접적인 평가수요와 통계적 모형을 이용한 간접적 평가수요를 비교하고 설문조사의 대체 방법을 제시하였다.

• Environmental and Resource Economics Review
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• v.8 no.1
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• pp.51-73
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• 1998

조건부가치측정법(CVM)의 지불의사 유도방법인 이중 양분선택형 질문법은 단일 양분선택형 질문 CV자료의 통계적 비효율성을 극복하기 위한 방법으로 제안되었다. 이 방법은 여러 가지 장점에도 불구하고 출발점 편의의 심리학적 근거인 정박효과 (anchoring effect)의 발생 가능성을 의심받고 있다. 그러므로 본 논문에서는 이중 양분선택형 질문 CV자료에서 정박효과를 검토할 수 있는 일반적 지불의사금액모형을 제시하고, 그 모형으로부터 정박효과를 검토할 수 있는 방법을 제안한다. 모형은, Cameron and Quiggin(1994)이 제안한 이변량 모형에 두 번째 내재 지불의사금액의 설명변수로서 처음 제시된 특정금액에 대한 양분선택적 응답결과를 포함시킨 형태이다. 이 모형에서 처음 제시된 특정금액에 대한 양분선택적 응답결과의 계수 부호가 음(-)이고 통계적으로 유의하다면 정박효과가 발생하는 것으로 볼 수 있다. 그러나 만약 이러한 계수 검토에서 정박효과 발생을 확인할 수 없는 경우, 두 번의 응답에서 두 지불의사금액 추정치들의 평균이 다르다고 볼 수 없다면 정박효과를 우려할 필요가 없다. 이 검토 모형 및 방법을 본 연구에서 한강 수질 개선에 대한 CV자료에 적용해 본 결과 정박효과를 우려할 필요가 없음을 확인할 수 있다.

• The Korean Journal of Applied Statistics
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• v.27 no.2
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• pp.239-247
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• 2014

For a sensitive survey in which the population is composed by several strata with quantitative attributes, we present an additive stratified quantitative attribute randomized response model which applied stratified random sampling instead of simple random sampling to the models of Himmelfarb-Edgell's additive quantitative attribute model and Gjestvang-Singh's. We also establish theoretical grounds to estimate the stratum mean of sensitive quantitative attributes as well as the over all mean. We deal with the proportional and optimal allocation problems in each suggested model and compare the relative efficiency of the suggested two models; subsequently, Himmelfarb-Edgell's model is more efficient than Gjestvang-Singh's model under the condition of stratified random sampling.