• Journal of the Korean Data and Information Science Society
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• v.11 no.2
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• pp.279-293
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• 2000

This article suggests two change-point estimators which are modifications of Carlstein(1988) change-point estimators with rank functions and mean functions where there is one change-point in a mean function. A comparison study of Carlstein(1988) estimators and proposed estimators is done by simulation on the mean, the MSE, and the proportion of matching true change-point.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.376-376
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• 2021

홍수와 같은 수문 재해를 예측하고 예방하기 위해서는 강우량을 정확하게 예측하는 것이 중요하다. 신뢰할 수 있는 수문재해 예보 시스템은 기존의 포인트 기반 우량계를 사용하여 달성 할 수 있는 것보다 강우량의 공간 분포를 관측할 수 있는 보다 효과적인 방법이 필요하다. 본 연구에서는 전파강수계 시스템과 다중 고도 관측 데이터를 이용하여 평균 강우를 추정하는 방법을 제시한다. 전파강수계는 K 밴드 이중 편파 기술을 사용하여 초단거리 관측을 수행하는 소형전파강수관측시스템이다. 평균 강우량을 추정하는 방법은 매우 짧은 관측 범위와 이중 편파 정보의 다중고도 평균 관측 개념을 기반으로 하며 관측 지역의 반사도와 비차등위상차의 고도별 평균값을 이용하여 추정한다. 제안 된 방법은 전파강수계의 관측 범위와 스캔 시간이 매우 짧기 때문에 강우 분포의 시공간적 변화가 낮다는 가정하에 개발되었다. 제안된 방법의 평가를 위해 핏게이지, 우량계 및 Parsivel disdrometer를 포함한 지상 장비와 비교하였다. 시험적용 결과 제안된 강우 추정 기법이 다양한 강우사상에 대해 강우강도를 잘 추정하는 것으로 확인되었다

• Journal of the Korean Data and Information Science Society
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• v.28 no.6
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• pp.1349-1360
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• 2017

This study was conducted to estimate the genetic parameters for common ketosis indicators (${\beta}$-hydroxybutyrate acid, BHBA; milk acetone), feed intake efficiency indicator (energy-corrected milk, ECM), and milk yield (MY) in Korean Holstein. A total of 75,072 monthly test-day records from 14,397 first parity cows were collected, between 2012 and 2016, from Korea animal improvement association enrolled farms. Variance components were estimated using a multiple trait random regression model. The heritability of BHBA and acetone levels ranged from 0.06 to 0.15 at different DIMs. The phenotypic and genetic correlations between BHBA and acetone were between 0.73 and 0.90, and between 0.93 and 0.98, respectively. The phenotypic correlation between BHBA and MY, between acetone and MY, between BHBA and ECM, and between acetone and ECM ranged from -0.18 to -0.05, -0.23 to -0.05, 0 to 0.10, and -0.09 to 0.01, respectively. Genetic correlation estimates between BHBA and MY, between acetone and MY, between BHBA and ECM, and between acetone and ECM also ranged from -0.55 to 0.05, -0.62 to -0.04, -0.10 to 0.11, and -0.20 to 0.00, respectively. We hope that these results would greatly assist in the improvement of ketosis disease in the local Holsteins.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.643-653
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• 2007

Average hydraulic conductivity was $2.64{\times}10^{-8}m/sec$ average RQD was 78%, average porosity was 0.51%, and range of groundwater level was $77.06{\sim}125.97m$ by measured in 8 boreholes at the Surak Mt. tunnel area. Groundwater level of two peaks in the Surak Mt. tunnel area were estimated through linear regression analysis for groundwater level versus elevation. And, average horizontal hydraulic gradient in the Surak Mt. tunnel area was calculated 0.267. Minimum, maximum, and average hydraulic conductivities that estimated by field tests were $5.56{\times}10^{-9}m/sec,\;6.12{\times}10^{-8}m/sec,\;and\;2.64{\times}10^{-8}m/sec$, respectively. Groundwater discharge rates per 1 meter that estimated using minimum, maximum, and average hydraulic conductivities and average horizontal hydraulic gradient were $0.00585m^2/day,\;0.06434m^2/day,\;and\;0.02775m^2/day$, respectively. Pure groundwater recharge rate per unit recharge area was calculated 223.96 mm/yr through water balance analysis. Prediction simulation of groundwater level fluctuation with minimum, maximum, and average hydraulic conductivities were conducted. Discharge rate into the Surak Mt. tunnel for minimum hydraulic conductivity was small, but groundwaer drawdown was highly. Discharge rate into the Surak Mt. tunnel for maximum hydraulic conductivity was higher, but groundwaer level was recovered quickly.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11a
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• pp.629-632
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• 2002

본 논문에서는 획득 영상에서 k-평균 알고리즘에 의한 무게중심을 이용하여 이동 물체를 검출하고 추적하는 방법을 제안하였다. 이동 물체의 검출은 획득 영상에 대하여 차영상 후 에지 검출에 의해 수행된다. 제안한 검출 방법은 빛의 밝기와 각도에 의해 발생된 그림자 등의 변형을 제거하고, 이동 물체만을 검출할 수 있어, 빛에 영향을 받은 영상에 대해서도 이동 물체를 양호하게 검출할 수 있다. 물체 추적은 검출된 이동 물체에 대하여 k-평균 알고리즘으로 세 개의 물체 무게중심을 구하고, 무게중심 부근의 화소 평균값과 무게중심간의 거리를 구한다. 다음 프레임들에 대하여 탐색영역의 화소 평균값에 의해 후보 무게중심을 구하고, 물체 무게중심과 구한 후보 무게중심들의 표준편차와 무게중심간의 거리 차를 이용하여 이동 물체를 추적한다. 그 결과, 이동 물체의 추적 속도를 개선시켰고, 물체 추적 오차율을 줄였다.

• Annual Conference on Human and Language Technology
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• 2001.10d
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• pp.465-471
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• 2001

본 연구에서는 동형이의어 분별을 위하여 허정(2000)이 제시한 "사전 뜻풀이말에서 추출한 의미정보에 기반한 동형이의어 중의성 해결 시스템" 이 가지는 문제점과 향후 연구과제로 제시한 문제들을 개선하기 위하여 Bayes 정리에 기반한 동형이의어 분별 모델을 제안한다. 의미 분별된 사전 뜻풀이말 코퍼스에서 동형이의어를 포함하고 있는 뜻풀이말을 구성하는 체언류(보통명사), 용언류(형용사, 동사) 및 부사류(부사)를 의미 정보로 추출한다. 동형이의어의 의미별 사전 출현 빈도수가 비교적 균등한 기존 9개의 동형이의어 명사를 대상으로 실험하여 비교하였고, 새로 7개의 동형이의어 용언(형용사, 동사)을 추가하여 실험하였다. 9개의 동형이의어 명사를 대상으로 한 내부 실험에서 평균 99.37% 정확률을 보였으며 1개의 동형이의어 용언을 대상으로 한 내부 실험에서 평균 99.53% 정확률을 보였다. 외부 실험은 국어 정보베이스와 ETRI 코퍼스를 이용하여 9개의 동형이의어 명사를 대상으로 평균 84.42% 정확률과 세종계획의 350만 어절 규모의 외부 코퍼스를 이용하여 7개의 동형이의어 용언을 대상으로 평균 70.81%의 정확률을 보였다.

• Journal of Chest Surgery
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• v.29 no.5
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• pp.542-547
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• 1996

All patients who underwent video-assisted thoracic surgery (VATS) for diagnostic purposes from Jan. 1992 to Aug. 1995 were reviewed. The total number of patients were 111 with 57 male and 54 female, and the mean age was 49 years (range 1 to 74). Multiple biopsies from more than one location were performed in 17 patients , pleural biopsies were performed In 49 patients, lung biopsies in 43 patients, mediastinal mass or Iymph node biopsies in 33 patients, and two pericardium biopsies and one dia- phragm biopsy, for a total of 128 biopsies. Seventeen pleural biopsy cases and one lung biopsy case underwent operation under local anesthesia , the rest were performed under general anesthesia. In patients who underwent lung biopsy, the mean age was 49.1 ye rs (range 22~ 73). The operating time was 40 to 170 minutes (mean 97), intravenous or intramuscular injection for pain control was required 0 to 22 times(mean 4.7), and chest tube was inserted from 1 to 26 days(mean 7). In all patients except two, a diagnosis was obtained from the biopsy and complication was encountered in one patient in whom intraoperative paroxysmal atrial tachycardia was detected. In 7 patients, a thorn- cotomy had to be done due to pleural adhesion or intraoperative bleeding, and 7 patients had postoperative complications associated with the chest tube. In the pleural biopsy group, the mean age was 49 years (range 17~ 74). The operating time was 25 to 80 minutes (mean 49), intravenous or intramuscular injection for pain control was needed 0 to 20 times (mean 3.6), and the chest tube was i.nserted for 0 to 67 days(mean 9.8). In all the patients, a diagnosis was possible. The chest tube was inserted for longer than 7 days in 11 patients. In the Iymph node biopsy roup, the mean age was 44.2 years (range 1 ~ 68). The operating time was )0 to 3)5 minutes(mean 105), pain control was required 0 to 15 times(mean 3.2), and a chest tube was kept in place for 1 to 36 days(mean 6.1). In one patient, a diagnosis was not possible and a chest tube was kept in place for longer than 7 days in 7 patients. In the multiple biopsy group, the mean age was 53.1 years(range 20~ 71). The operating time was 15 to 165 minutes(mean 85), and pain control was done from 0 to 17 times(mean 3.1). The chest tube was kept in place for 1 to 16 days (mean 7.9).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.143-150
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• 1976

A trial has been made to find out a new method of calculating the survival rate of a fish Population utilizing the length composition data and the characteristics of the frequency curve of the length which usually is normal distribution curve. In this paper, a stochastic method is introduced and applied to calculate the survival rate of yellow croaker caught by Korean trawlers in the Yellow Sea and the East China Sea in 1971. The results are as follows : Mean of survival rate 0.46089 Variance 0.03073 Standard deviation 0.17529 95 percent confidence interval 0.36040-0.56138.

• Journal of the Korean Data and Information Science Society
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• v.22 no.2
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• pp.189-196
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• 2011

In this study, we perform a simulation study to compare frequently used standardization methods for interview scores based on trimmed mean, rank mean, and z-score mean. In this simulation study we assume that interviewer's score is influenced by a weighted average of true interviewee's true score and independent noise whose weight is determined by the professionality of the interviewer. In other words, as interviewer's professionality increases, the observed score becomes closer to the true score and if interviewer's professionality decreases, the observed score becomes closer to the noise instead of the true score. By adding interviewer's tendency bias to the weighed average, final interviewee's score is assumed to be observed. In this simulation, the interviewers's cores for each method are computed and then the method is considered best whose rank correlation between the method's scores and the true scores is highest. Simulation results show that when the true score is from normal distributions, z-score mean is best in general and when the true score is from Laplace distributions, z-score mean is better than rank mean in full interview system, where all interviewers meet all interviewees, and rank mean is better than z-score mean in half split interview system, where the interviewers meet only half of the interviewees. Trimmed mean is worst in general.

• Journal of dental hygiene science
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• v.6 no.2
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• pp.113-117
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• 2006

The purpose of this study was to evaluate caries preventive effects of a school-based weekly mouthrinsing program with a 0.2% sodium fluoride solution for five years at elementary school in Yangsan city, which were conducted for 330 children of elementary school from 2000 to 2005. The surveyed data was analyzed with SPSS statistical package. The obtained results were as follows; 1. DMF rate was 58.4% before the mouthrinsing program in 2000 and 48.3% after the program in 2005. DMF rate in 2005 decreased by 10.1% compared to DMF rate in 2000. 2. DT index was 2.46 before the mouthrinsing program and 1.70 after the program. DT index in 2004 decreased by 0.76 compared to DT index in 2000. 3. FT index was 0.55 before the mouthrinsing program and 0.37 after the program. Filled teeth due to decay after the program decreased by 0.18 compared to filled teeth before the program. 4. DMFT score was 2.61 before the mouthrinsing program and 1.64 after the program. DMFT score in 2004 decreased by 0.97 compared to DMFT score in 2000. 5. PHP index was 12.12 before the mouthrinsing program and 5.95 after the program. PHP index in 2005 decreased by 6.17 compared to PHP index in 2000.