• 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.

• East Asian mathematical journal
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• v.29 no.2
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• pp.189-205
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• 2013

Addition problems can be divided into the 'problem of quantity' which does not have the concept of object or unit, and the 'problem of number' which have the concept of object or unit. 'Additive property' is the factor which has to be considered in the former case. On the other hand, 'additive property' is not considered and meaningless in the latter case. However, this additive property is not emphasized in the elementary curriculum that mostly deals with quantitative problems, so related errors are occurred in actual life. In this study, we will investigate to the pre-service elementary teachers through the problems of deciding the additive property. The result shows that the pre-service elementary teachers' cognition of additive problems is insufficient. This study will provide focal points in the teacher education and the elementary education, and the clues for the operating programs through the information about the tendency of errors.

• The Korean Journal of Applied Statistics
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• v.23 no.1
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• pp.207-218
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• 2010

Generalized additive model(GAM) is the statistical model that resolves most of the problems existing in the traditional linear regression model. However, overfitting phenomenon can be aroused without applying any method to reduce the number of independent variables. Therefore, variable selection methods in generalized additive model are needed. Recently, Lasso related methods are popular for variable selection in regression analysis. In this research, we consider Group Lasso and Elastic net models for variable selection in GAM and propose an algorithm for finding solutions. We compare the proposed methods via Monte Carlo simulation and applying auto insurance data in the fiscal year 2005. lt is shown that the proposed methods result in the better performance.

• Journal of Korea Technology Innovation Society
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• v.3 no.1
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• pp.37-54
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• 2000

본 글에서는 최근 기술가치평가에 적용되고 있는 조건부가치평가법(Contingent Valuation Method) 다속성효용평가법(Multi-attribute Utility Assessment) 그리고 조건부청구권가치평가법(Real Option Pricing Method)의 세가지 가치측정기법들의 특징과 조요 관련 문헌들을 간략하게 정리하여 소개함으로서 관심있는 연구자들에게 유용한 정보를 제공하고자 한다. 소개하는 방법론들은 환경재화의 가치측정기법과 위험도가 높은 에너지프로젝트의 가치평가기법으로 개발된 기법들로서 신기술이 가지는 특징인 외부성 등의 비시장재적 특성과 높은 위험도에따른 투자가치를 반영할 수있어 기술 및 기업의 가치평가 사례연구에 응용할 수있다.

• Journal of the Korean Statistical Society
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• v.4 no.1
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• pp.9-17
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• 1975

A, B 두 요인의 영향을 받고 있다고 생각되는 rc개 측정치가 있고 이것이 다음과 같이 $r\timesc$ 이차분류표로 정리되었다고 하자. 여기에서 $$y_{ij} = \mu + \alpha_i + \beta_j + \epsilon_{ij}$$ 와 같은 가법모형을 생각한다. 그리고 $\epsilon_{ij}$는 잔여항으로써 평균이 0, 분산이 $\sigma^2$인 정규분포를 한다고 가정하는 것이 보통이다. 또 이것은 모수모형인 경우 $E(y_{ij}) = \mu + \alpha_i + \beta_i, v(y_{ij}) = \sigma^2$임을 의미하는 것으로 생각된다. 그러나 자료에 따라서는 위에서와 같은 가법적 모형을 적용한다는 것이 적당하지 못한 경우가 있다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.6
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• pp.1693-1702
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• 1999

This paper proposes the use of an adaptive Wiener filter for edge-preserving image filtering. Images are partitioned into a set of blocks of pixels which is divided into five subsets of blocks according to their edge contents and orientations. Each subset of blocks is used to define a covariance matrix, from which a Wiener filter is derived. Five covariance matrices and Wiener filters are thus obtained. An image-block classifier using the five sets of covariance matrices of the class is designed to classify each incoming block of pixels according to its edge content in the presence of noise. Experimental results are included to verify the usefulness of the proposed method.

• Environmental and Resource Economics Review
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• v.29 no.1
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• pp.1-22
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• 2020

While contingent valuation method (CVM) has been widely used for non-market valuations, it has been argued that it may suffer from hypothetical bias. However, if CVM respondents believe that their responses could affect the real consequence, the method could satisfy consequentiality. If a CVM satisfies a sufficiently high consequentiality, hypothetical bias could disappear as shown by some previous studies. In this study, we experimentally compare the willingness to pay (WTP) for donation of a relatively high consequentiality group with that of a relatively low consequentiality group for Korean university students. We find that both the existence probability and the size of hypothetical bias are lower for the high consequentiality group. This result implies that a CVM for a real policy including environmental policies could be free from hypothetical bias because its consequentiality would be relatively high, and warrants a future field study investigating the effect of consequentiality on hypothetical bias.

• Journal of Wetlands Research
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• v.11 no.3
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• pp.21-35
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• 2009

To propose a sound direction for river rehabilitation plan, the naturalness of the river must be evaluated. In this study, the conventional methods for evaluating the naturalness of rivers proposed by Park, et al. has been improved to estimate the weights for each items subject to assessment and applied adequate Analytic Hierarchy Process (AHP). To estimate the weights, survey was conducted on a group of 83 experts in Civil and Environmental Engineering with a customized questionnaire. The results of the survey were generalized and used to estimate the weights of each items. Among the 14 evaluation items that have been generated as a result of the estimation, a total of 7 weight values such as water quality, variations in water flow, vegetation around minor bed, curve of waterway, vegetation around flood plain, variety in minor bed width, and diversity of stream bed materials appeared to be high. The improved method for evaluating the naturalness of rivers was applied to Hoe-ya River, where the method has successfully discriminated the sections having low degree of naturalness. The proposed assessment method can be employed as a criterion to determine the business zones in the river environment maintenance projects.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.140-144
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• 2005

In this paper, an almost everywhere convergence theorem for seminormed fuzzy co-integrals is showed provided that the fuzzy measure is null-additive.

• Explosives and Blasting
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• v.40 no.3
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• pp.44-53
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• 2022

This study evaluates the applicability of the TNT Equivalency Method, Multi-Energy Method, and Baker-Strehlow-Tang (BST) Method, which are blast prediction models used to determine the overpressure of blast wave generated from vapor cloud explosion. It is assumed that the propane leaked from a propane storage container with a capacity of 2000 kg installed in an area where studio houses and shopping centers are concentrated causes a vapor cloud explosion. The equivalent mass of TNT calculated by applying the TNT Equivalency Method is found to be 4061 kg. Change of overpressure with the distance obtained by the TNT Equivalency Method, Multi-Energy Method, and BST Method is rapid and the magnitude of overpressure obtained by the TNT Equivalency Method and BST method is generally similar within 100 m from explosion center. As a result of comparing the overpressure observed in the actual vapor cloud explosion case with the overpressure obtained by applying the TNT Equivalent Method, Multi-Energy Method, and BST Method, the BST Method is found to be the best fit. As a result of comparing the overpressure with the distance obtained by each explosion prediction model with the damage criteria for structure, it is estimated that the structure located within 90 m from explosion center would suffer a damage more than partial destruction, and glass panes of the structure separated by 600 m would be fractured.