• 정보처리학회논문지B
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• 제10B권4호
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• pp.465-472
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• 2003

얼굴영상을 효율적으로 처리하기 위해선 먼저 인력영상에서 얼굴영역과 얼굴을 구성하는 각 요소를 검출하고 얼굴의 회전각을 추정하는 전처리과정이 필요하다. 본 논문에서는 다양한 얼굴의 크기와 머리회전, 조명의 변화가 허용되고 피부색과 비슷한 배경이 얼굴에 병합되는 경우에도 얼굴과 요소들(눈, 입)을 강건하게 검출할 수 있는 방법을 제안한다. 변환된 HSV 컬러 좌표계상의 대역적 피부 색상정보와 히스토그램을 이용한 피부 색상정보로 얼굴후보영역을 지정한 뒤, 같은 방법으로 얼굴후보영역 안에서 입술영역을 검출한다. 입술영역의 횡축 기울기로 x축에 대한 회전각을 추정한 후, 얼굴의 모양정보와 요소의 위치정보를 이용해 얼굴임을 확정한다. 다음으로 양안의 조합으로 이루어진 부분 템플릿매칭을 통해 눈을 검출한 뒤, 얼굴의 넓이를 참조한 3차원 공간상에서의 눈의 위치를 계산하여 y축 회전각을 추정한다. 다양한 얼굴영상에 대해 실험을 실시한 결과, 본 알고리즘의 유효성을 확인하였다.

• 조명전기설비학회논문지
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• 제16권5호
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• pp.29-37
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• 2002

본 논문에서는 전자파 측정기법을 이용하여 부분방전 발생 전·후에 검출된 신호를 분석하여 폐쇄 배전반의 이상 징후를 상시 감시할 수 있는 사고 예방진단기법을 제시하였다. 폐쇄 배전반의 정상 및 이상상태 판단을 위해 배전반 내부 및 외부에 헬리컬 안테나를 설치하여 이들 안테나에서 검출된 부분방전 발생 전·후의 신호를 주파수 스펙트럼 분석을 통해 크기를 비교 분석하였다. 본 논문에서는 부분방전 발생 전·후에 폐쇄 배전반 내부 및 외부에 설치된 안테나에서 검출된 신호들을 이용하여 정상상태 및 이상상태를 판별하는 방법을 적용하여 좋은 결과를 얻었으며, 향후 폐쇄 배전반의 절연 상태 감시 및 사고예방에 효율적으로 적용할 수 있으리라 기대된다.

• 정보처리학회논문지B
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• 제15B권2호
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• pp.81-86
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• 2008

이 논문에서 겹쳐지고 잘린 이미지내의 타원형 객체들 가운데 부분적으로 겹쳐져 보이지 않는 외형과 객체 내 영역을 재구성하고 계산하기 위한 방법을 제안한다. 대칭 속성을 이용하여 부분적으로 겹쳐져 보이지 않는 객체를 인식하기 위해서 객체내의 부분인식에 기반을 둔 방법이다. 이 방법은 객체 내에서 대칭축을 이용하여 영역 복사를 통한 보이지 않는 영역을 복원하는 간결한 방법을 제시한다. 이 방법은 통계적 예측보다 대칭 기반의 객체 복원에 의존하기 때문에 부분적으로 겹쳐져 보이지 않는 부분에 대해서 측정된 변수를 가지고 분류 트리를 이용하여 객체 인식를 수행한다. 이는 비록 객체의 자세에는 한계를 가지고 있지만 크기 변경이나 회전, 시각의 변화에서 부분적으로 가려진 객체를 인식하는데 뛰어난 것으로 나타났다.

• 대한조선학회논문집
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• 제44권6호
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• pp.666-674
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• 2007

It is very important to estimate static squeezing pressure distributions for lining material of sterntube after bearing at dry dock stage since the maximum squeezing pressure value can be one of the significant characteristics representing coming navigation performances of the propulsion system. Moderate oil film pressure between lining material and propulsion shaft is also essential for safe ship service. In this paper, Hertz contact theory is explained to derive static squeezing pressure. Reynolds equation simplified from Navier-Stokes equation is centrally differentiated to numerically obtain dynamic oil film pressures. New shaft alignment technology of nonlinear elastic multi-support bearing elements is also used in order to obtain external forces acting on lining material of bearing. For 300K DWT class VLCC with synthetic bush of sterntube after bearing, static squeezing pressures are calculated using derived external forces and Hertz contact theory. Optimum partial slope of the after bush is presented by parametric shaft alignment analyses. Dynamic oil film pressures are comparatively evaluated for partially bored and unbored after bush. Finally it is proved that the partial slope can drastically reduce oil film pressure during engine running.

• Journal of electromagnetic engineering and science
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• 제18권2호
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• pp.94-100
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• 2018

Partial discharges (PDs) are electrical sparks that occur inside insulation between two conducting electrodes and can lead to the disastrous failure of insulation systems. To determine the location of a PD, a distributed array of UHF PD sensors is used to detect the electromagnetic (EM) signals emitted from the PD source, and the localization of the PD source can be estimated using the time difference of arrival (TDOA) between EM signals captured by the UHF PD sensor array. There are four popular methods to estimate the TDOA-the first peak method, the cross-correlation method, the energy criterion method, and the average time window threshold method. In this work, we numerically investigate the influence of noise on estimating the TDOA for the four different methods. Numerical results show that the energy criterion method is more robust against noise than other methods.

• 대한산업공학회지
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• 제39권4호
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• pp.253-259
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• 2013

Investment scenarios in the transportation network design problem usually contain installation or expansion of multi-mode transportation links. When one applies the mode choice analysis and traffic assignment sequentially for each investment scenario, it is possible that the travel impedance used in the mode choice analysis is different from the user equilibrium cost of the traffic assignment step. Therefore, to estimate the travel impedance and mode choice accurately, one needs to develop a combined model for the mode choice and traffic assignment. In this paper, we derive the inverse demand and the excess demand functions for the multi-mode multinomial logit mode choice function and develop a combined model for the multi-mode variable demand traffic assignment problem. Using data from the regional O/D and network data provided by the KTDB, we compared the performance of the partial linearization algorithm with the Frank-Wolfe algorithm applied to the excess demand model and with the sequential heuristic procedures.

• Journal of Electrical Engineering and Technology
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• 제6권5호
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• pp.677-683
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• 2011

The present paper describes the setup of standard partial discharge calibrator for measuring partial discharge and estimating uncertainties. The standard PD calibrator was designed and set up, consisting of a digital pulse generator, capacitor modules, and a digital oscilloscope controlled by software developed in the laboratory. Using this software, averages of charges and rising times and their standard deviations in the measured pulses can also be calculated. The standard PD calibrator generates five types of pulses: single, double, random, oscillating, and long-rising. The coefficient sensitivities to estimate the uncertainties of pulses were extracted in the model circuit of the standard PD calibrator. The uncertainties of charges and rising times in pulses of the standard PD calibrator were estimated with single pulses. These values were 0.3%-1.4% in charges and 1.9%-7.0% in rising time; however, these values are lower than the limit values in IEC 60270.

• 응용통계연구
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• 제32권2호
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• pp.187-198
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• 2019

ROC와 CAP 곡선을 이용하여 다양한 정확도 측도를 바탕으로 최적분류점을 추정하는 많은 연구가 있다. 본 연구에서는 ROC와 CAP 곡선의 특정한 부분 면적을 나타내는 대안적인 통계량을 제안한다. 새롭게 정의된 부분 면적을 나타내는 통계량의 미분방정식을 이용하여 ROC와 CAP 함수와의 관계를 살펴보고, 다음으로는 ROC와 CAP 곡선에 대한 다양한 정확도 측도들의 조건에서의 최적분류점과의 관계를 유도한다. 혼합분포를 구성하는 두 종류의 분포함수를 다양한 정규분포로 가정하여 최적분류점을 설정하고, 다양한 정확도 측도들의 조건에서의 최적분류점에 대응하는 제1종과 제2종 오류의 크기를 탐색하고 토론한다.

• The Journal of Advanced Prosthodontics
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• 제5권4호
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• pp.388-395
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• 2013

PURPOSE. The purpose of this study was to estimate the effects of occlusal stability to identify action mechanisms of mouthguards, known to have a modulatory effect on limb muscle function. MATERIALS AND METHODS. This study included 20 male subjects to perform the isokinetic muscle tests and the Wingate anaerobic power test on both knee joints under five closed-mouth conditions: without or with 4 types of mouthguards with thickness of 2 mm based on premolar area: (1) full-coverage, (2) anterior partial-coverage, (3) right posterior partial-coverage, and (4) left posterior partial-coverage. The obtained results were subjected to One-way ANOVA with repeated measures, followed by post hoc test of the contrast method (${\alpha}$=.05). RESULTS. There was no significant difference between the closed position with and without a full-coverage mouthguard in all variables. However, significant differences were observed between with and without a partial-coverage mouthguard in muscular endurance during extension of the left knee, muscular power and endurance during flexion of the right knee. Additionally, significant differences were found between occlusal states with full- and partial-coverage mouthguards in muscular power and endurance during extension of the left knee. CONCLUSION. These findings indicate the elevation of vertical dimension by 2 mm or the inducement of occlusal stability had little effect on isokinetic muscle strength and anaerobic performance, while uneven distribution of occlusal force might have some positive effects.

• Journal of Animal Science and Technology
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• 제55권6호
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• pp.489-500
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• 2013

Daily milk yields on test days were estimated using morning or afternoon partial milk yields collected by official agencies and the accuracy of the estimates was determined. Test-day data for milk yields consisted of 3,156,734 records of AM/PM partial milking measurements of 255,437 milking Holstein cows from 3,708 farms collected from December 2008 to April 2013. A linear regression model (LRM) was applied to estimate daily milk yields using alternate AM/PM milk yield records within lactation stages, milking intervals, and parities on every daily milk yield. The alternate statistical approach was a non-linear hierarchical model (NHM) in which Brody's growth function was implemented by reflecting an animal's physiological milk production cycle. When compared with LRM, daily milk yields predicted by the NHM were assumed to be functionally related to day in milk (or lactation) stage, milking intervals, and partial milk yields. Since the results were in terms of accuracies based on comparisons of different statistical models, accuracies of estimates of daily milk yields by NHM were close to those determined by the LRM. The average of these accuracies was 0.94 for AM partial milk yields and 0.93 for PM partial milk yields for first calving cows. However, the accuracies of AM/PM milk yield estimations from cows under a calving stage higher than the first parity were 0.96 and 0.95, respectively. Correlations between the estimated daily milk yields and the actual daily milk yields ranged from 0.96~0.98. These accuracies were lower for unbalanced AM/PM milking intervals and the first calving cows. Overall, prediction of daily milk yields by NHM would be more appropriate than by LRM due to its flexibility under different milk yield-related circumstances, which provides an idea of the functional relationship between milking intervals and days in milk with daily milk yields from statistical viewpoints.