• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.6
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• pp.537-543
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• 2016

A new approach to systematically model aerodynamic coefficients using an adaptive sampling based wind tunnel testing considering cost is proposed. The Latin Hypercube design is used for selecting initial test points. The Gaussian Process (GP) is iteratively used during the experiment to determine additional experimental points that minimizes the uncertainty reduction per incremental cost. A numerical simulation based experiment was conducted using the static aerodynamic coefficient database a fighter aircraft, which demonstrated the validity of the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.8B
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• pp.1141-1151
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• 2001

본 논문에서는 효과적으로 선택된 초기 탐색 위치를 이용한 움직임 추정의 고속 알고리즘을 제안하였다. 제안된 알고리즘에서는 2$\times$2화소 블록 평균으로 부표본화 영상에서 움직임 벡터를 얻어 원영상 비율로 확대하고, 주위 블록의 움직임으로부터 예측 움직임 벡터를 구하여, 이 중에서 정합오차가 작은 것을 초기 탐색 위치로 선택한다. 그리고 선택된 초기 탐색 위치를 중심으로 회전 탐색을 시작하여, 연속 소거 알고리즘으로 탐색할 후보 블록을 선택하고, 부분 정합 왜곡 소거법을 사용하여 블록간 정합오차 계산량을 줄이면서, 고속으로 움직임 벡터를 추정한다. 알고리즘의 실제 적용에 있어서는 선택된 초기 탐색 위치를 중심으로 회전 탐색 패턴의 탐색 범위를 조절하거나, 매크로 블록 당 복잡도를 제한하여 계산량을 줄일 수 있다. 실험 결과, 제안된 알고리즘은 전역탐색 블록정합 알고리즘에 대하여 0.2dB 이하의 미소한 평균 PSNR 저하만을 발생하면서, FBMA 복잡도의 3% 이하의 평균 복잡도를 소요하였다. 이것은 3단계 탐색법에 대하여 40% 이하의 계산량이다. 그리고 실험 영상들의 각 프레임에 대해서도 비슷한 성능을 보임을 확인하였다.

• Korean Journal of Biological Psychiatry
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• v.5 no.1
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• pp.3-16
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• 1998

The neurophysiological study has been widely used in search of the relationship between brain and behavior. The basic techniques for the animal experiments of this kind such as stereotaxic techniques, lesioning methods, the methods of electrical stimulation and recording, and confirmation of histological location were briefly reviewed. Nevertheless, the importance of complementary neurochemical, neuroanatomical and behavioral studies can not be neglected.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.6
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• pp.1-11
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• 2010

The purpose of this research is to identify satisfaction levels of the arboretum which will be provided in the Multifunctional Administrative City and to estimate the economic value of using choice experiments. The attributes were "Preservation", "Education", "Recreation", "Facility", "Accessibility" and the entrance fee. The main effects model was utilized to construct hypothetical alternatives. Calibration of the conjoint choice model revealed that 'wetlands' and 'forest trails' in "Preservation" and the "Recreation", respectively, were significant variables. This result indicates that respondents are willing to pay more for these if they are provided in the arboretum. Also, 'variety seeking' tendency, age, and income level positively influenced the provision of the arboretum. Involvement in preservation of natural environment, however, had a negative influence on the establishment of the arboretum. Because this study is the first attempt to estimate the economic valuation of an urban arboretum using choice experiment, there are several suggestions for future research in terms of determining the base level and inclusion of salient attribute levels.

• Proceedings of the Korean Statistical Society Conference
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• 2003.10a
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• pp.263-268
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• 2003

Breiman, Friedman, Olshen and Stone(1984)의 전체탐색법에 의한 회귀나무는 상대적으로 많은 분리가 가능한 변수로 분리기준이 정해지는 편의 현상을 갖고 있다. 본 연구에서는 이런 문제점을 해결할 수 있는 알고리즘을 제안하여 변수선택편의가 없는 회귀나무를 만들고자 한다. 제안하는 알고리즘은 노드의 분리변수를 선택하는 단계와 그 선택된 변수에 의해 이진분리를 위한 분리점을 찾는 단계로 구성되어 있다. 예측변수 중에서 목표변수와 가장 밀접하게 연관된 예측변수는 예측변수의 자료의 종류에 따라 스피어만의 순위상관계수에 의한 검정 혹은 크루스칼-왈리스의 통계량에 의한 검정을 수행하여 가장 통계적으로 유의한 변수로 선택하였고, 선택된 변수에만 Breiman et al.(1984)의 전체선택법을 적용하여 분리점을 결정하였다. 모의실험을 통해 변수선택편의, 변수선택력 , 그리고 평균제곱오차 측면에서 Breiman et al. (1984)의 CART(Classification and Regression Trees)와 제안한 알고리즘을 서로 비교하였다. 또한, 두 알고리즘을 실제 자료에 적용하여 효율을 서로 비교하였다.

• The Korean Journal of Applied Statistics
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• v.28 no.5
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• pp.1035-1046
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• 2015

Variance components models incorporate various random factors in the form of linear models. There are two experimental Layouts for the classification of factors under variance components models: nested classification and crossed classification. We consider two-way variance components models and investigate the effect of experimental Layout on the performance of model selection criteria AIC and BIC. The effect of experimental Layout is studied through a simulation study with various combinations of parameters in a systematic fashion. The simulation study shows differences in performance of model selection methods between the two classification. There is a particular tendency to prefer the smaller model than the true model when the variance component of a nested factor becomes relatively larger than a nesting factor that is persistent even when the sample size is not small.

• The Korean Journal of Food And Nutrition
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• v.22 no.4
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• pp.696-700
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• 2009

The adaptability of dry rehydratable film for the qualitative evaluation of coliform bacteria and Escherichia coli was tested. In general, culture methods that employ lactose broth or desoxycholate lactose agar are used for qualitative tests of coliform bacteria. Culture using lactose broth showed a high detection yield and low selectivity when compared to the dry rehydratable film. However, culture methods that employ lactose broth required a long time(48 hrs) for qualitative tests of coliform bacteria and complicated procedures were required to prepare the medium. The detection of coliforms using desoxycholate lactose agar had a slightly higher selectivity than the dry rehydratable film method, but this difference was not statistically significant. However, the preparation of the desoxycholate lactose agar was complicated. EC broth for the detection of E. coli showed the highest detection yield and lowest selectivity; however, this method required complicated procedures for preparation of the medium as well. Overall, the dry rehydratable film had a slightly lower detection yield than the other methods. The detection yield of dry rehydratable film method was over 37.1% at a concentration of 1 cfu/$m{\ell}$. Additionally, the dry rehydratable film method showed high selectivity and did not require preparation. However, because the selectivity of the dry rehydratable film was high, it took a long time(36 hrs) to detect E. coli. Overall, these findings indicate that dry rehydratable film can be used for qualitative detection of coliforms and E. coli.

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2011.03a
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• pp.3-5
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• 2011

• Journal of the Korean Data and Information Science Society
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• v.9 no.2
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• pp.179-188
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• 1998

Local polynomial regression estimation is the most popular one among kernel type regression estimator. In local polynomial regression function esimation bandwidth selection is crucial problem like the kernel estimation. When the regression curve has complicated structure variable bandwidth selection will be appropriate. In this paper, we propose a variable bandwidth selection method fully data driven. We will choose the bandwdith by selecting minimising estiamted MSE which is estimated by the pilot bandwidth study via croos-validation method. Monte carlo simulation was conducted in order to show the superiority of proposed bandwidth selection method.

• Environmental and Resource Economics Review
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• v.29 no.2
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• pp.247-270
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• 2020

The value of a statistical life (VSL) plays a very important role in estimating the benefits of environmental policy. It is used, for example, as a unit of monetization of health benefits resulting from the reduction of air pollutants, which is the basis of cost-benefit analysis of policies. The VSL can be defined as the value that people of each society are willing to pay to reduce the risk of death, so the value should reflect the characteristics of its members. In this study, we apply a choice experiment with 3,081 respondents collected through a web survey were divided into two samples according to the type of questions. Among the various estimates, the most appropriate estimate of the VSL is about 1.3 billion won from 1,528 sample, which is similar to the results of the meta-analysis using estimates from prior studies conducted in Korea. In addition, this study shows that a private prevention program is preferred to reduce the risk of death from cancer rather than a public program.