• 한국컴퓨터정보학회논문지
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• 제20권12호
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• pp.169-174
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• 2015

Permutation p-values are provided for the agreement measures for multivariate interval data among many raters. Three agreement measures, Berry and Mielke's measure, Janson and Olsson's measure, and Um's measure are described and compared. Exact and resampling permutation methods are utilized to compute p-values and empirical quantile limits for three measures. Comparisons of p-values demonstrate that resampling permutation methods provide close approximations to exact p-values, and Berry and Mielke's measure and Um's measure show similar performance in terms of measuring agreement.

• 치과방사선
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• 제28권2호
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• pp.387-413
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• 1998

Image resampling is of particular interest in digital radiology. When resampling an image to a new set of coordinate, there appears blocking artifacts and image changes. To enhance image quality, interpolation algorithms have been used. Resampling is used to increase the number of points in an image to improve its appearance for display. The process of interpolation is fitting a continuous function to the discrete points in the digital image. The purpose of this study was to determine the effects of the seven interpolation functions when image resampling in digital periapical images. The images were obtained by Digora, CDR and scanning of Ektaspeed plus periapical radiograms on the dry skull and human subject. The subjects were exposed to intraoral X-ray machine at 60kVp and 70 kVp with exposure time varying between 0.01 and 0.50 second. To determine which interpolation method would provide the better image, seven functions were compared; (1) nearest neighbor (2) linear (3) non-linear (4) facet model (5) cubic convolution (6) cubic spline (7) gray segment expansion. And resampled images were compared in terms of SNR(Signal to Noise Ratio) and MTF(Modulation Transfer Function) coefficient value. The obtained results were as follows ; 1. The highest SNR value(75.96dB) was obtained with cubic convolution method and the lowest SNR value(72.44dB) was obtained with facet model method among seven interpolation methods. 2. There were significant differences of SNR values among CDR, Digora and film scan(P<0.05). 3. There were significant differences of SNR values between 60kVp and 70kVp in seven interpolation methods. There were significant differences of SNR values between facet model method and those of the other methods at 60kVp(P<0.05), but there were not significant differences of SNR values among seven interpolation methods at 70kVp(P>0.05). 4. There were significant differences of MTF coefficient values between linear interpolation method and the other six interpolation methods (P< 0.05). 5. The speed of computation time was the fastest with nearest -neighbor method and the slowest with non-linear method. 6. The better image was obtained with cubic convolution, cubic spline and gray segment method in ROC analysis. 7. The better sharpness of edge was obtained with gray segment expansion method among seven interpolation methods.

• 한국컴퓨터정보학회논문지
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• 제24권6호
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• pp.159-164
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• 2019

The statistical inference of Cronbach's alpha measure of internal reliability is known to be inaccurate when sample size is small and the assumption of normality is violated. In this paper, we describe the permutation method in which we compute resampling p-values for testing the difference between two or more independent Cronbach's alpha coefficients. When the over-all permutation test is significant, we also make pairwise post-hoc comparisons using permutaion method. The permutation tests for the equality of two independent Cronbach's alpha coefficients and three independent Cronbach's alpha coefficients are illustrated with an example analysis of survey data.

• Journal of the Korean Data and Information Science Society
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• 제27권4호
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• pp.899-910
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• 2016

근사검정은 종종 표본이 작은 순서척도의 범주를 갖는 분할표를 분석할 때 그 p값이 과대추정 되거나 과소추정 되기 때문에 적절하지 못한 것으로 여겨진다. 본 논문에서는 순서화된 범주를 갖는 $k{\times}k$ 분할표에서 특정 범주에 대한 가중 일치도에 대해 정확한 p값과 재표본 기법에 의해 p값을 구하는 퍼뮤테이션 방법을 제시한다. 이를 위해 두 명의 평가자가 특정의 범주에서 얼마나 일치된 평가를 하는 지를 측정하기 위해 $Kv{\dot{a}}lseth$가 제안한 특정 범주에 대한 가중 일치도 (weighted specific-category kappa)를 사용한다. 사례 데이터로서 $3{\times}3$ 분할표 형태의 실제 데이터와 가상데이터 그리고 $4{\times}4$ 분할표 형태의 가상데이터를 이용하며, 정확한 퍼뮤테이션 p값과 재표본 퍼뮤테이션 p값 그리고 근사검정의 p값을 계산하여 비교한다.

• Communications for Statistical Applications and Methods
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• 제25권4호
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• pp.329-339
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• 2018

In this study, we propose tests for equality of several variances with the normality assumption. First of all, we propose the likelihood ratio test by applying the permutation principle. Then by using the p-values for the pairwise tests between variances and combination functions, we propose combination tests. We apply the permutation principle to obtain the overall p-values. Also we review the well- known test statistics for the completion of our discussion and modify a statistic with the p-values. Then we illustrate proposed tests by numerical and simulated data and compare their efficiency with the reviewed ones through a simulation study by obtaining empirical p-values. Finally, we discuss some interesting features related to the resampling methods and tests for equality among several variances.

• 환경생물
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• 제40권2호
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• pp.164-171
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• 2022

꽃노랑총채벌레(Frankliniella occidentalis)는 500종 이상의 기주를 가지고 토마토반점위조바이러스(Tomato spotted wilt virus; TSWV)를 매개하는 해충이다. 전 세계적으로 방제를 위해 노력하고 있지만 살충제를 이용한 방제는 저항성 그리고 환경 및 경제적 부담으로 인한 한계를 보였기 때문에 고정 정확도를 설정한 표본조사법(Fixed-precision level sampling plan)을 개발하였다. 고추(Capsicum annuum)의 꽃노랑총채벌레 성충 방제를 위한 표본 조사법은 공간분포분석, 표본추출 정지선 그리고 의사결정법으로 구성되었다. 표본추출은 식물체를 상단(지상에서 180 cm 이상), 중단(지상에서 120~160 cm 이상), 하단(지상에서 70~110 cm 이상)으로 나누어 각 높이별로 꽃 3개에서 나오는 꽃노랑총채벌레의 성충의 마리 수를 조사하였다. 표본 추출을 통해 꽃노랑총채벌레 성충의 밀도는 다른 식물체 위치(중단, 하단)보다 상단에서 높은 것으로 나왔다. 공간분포분석에서는 Taylor's power law (TPL)를 통해 도출한 각 위치별 계수를 공분산분석(ANCOVA)하여 차이를 비교하였다. ANCOVA 결과에서 도출된 절편과 기울기의 P 값이 각각 0.94, 0.87인 것을 통해 식물체 내 위치별로 차이가 없음을 확인한 후, 자료를 통합(pooling)하여 계산된 TPL 계수를 이용하여 표본추출 정지선을 구하였다. 꽃노랑총채벌레의 방제의사결정을 위한 방제밀도 수준(m₀)은 문헌을 참조하여 3과 18로 설정하였으며 설정값(m₀)을 이용해 최대표본수(N_max)도 조사하였다. 조사 결과, m₀=3, 18일 때 N_max값은 각각 약 97개, 1149개로 계산되었다. 개발된 모델의 적합성 검정을 위해 분석에 사용하지 않은 독립자료를 이용해 Resampling Validation for Sampling Program (RVSP) 프로그램으로 개발된 표본추출법의 적합성 평가를 실시하였고 적합한 정확도를 보이는 것으로 조사되었다.