• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2006년도 춘계학술발표대회
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• pp.653-656
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• 2006

본 논문은 Cumulative Distribution Function(CDF) 부합에 의한 영상 개선 방법에 대해서 제안하였다. 제안한 방법은 원본 영상의 히스토그램 분포도를 조사하여 히스토그램 그래프상의 특정 색도값들을 선정, 이 점들을 보간법을 이용하여 히스토그램을 재 작성한다. 이를 이용하여 원본 CDF 그래프를 크게 벋어나지 않고, 즉 밝기 정보가 크게 훼손 되지 않은 상태로 색도 값을 재 배치 함으로써 히스토그램 평활화와 스트레칭 효과를 모두 만족하는 영상 향상의 결과를 얻을 수 있다.

• 한국정보처리학회논문지
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• 제4권1호
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• pp.177-183
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• 1997

비 중심t분포의 누적함수는 두 정규모집단에서 모평균의 동일성 검정에서 검정력 계산 및 모 평균에 대한 표준편차의 비에 대하여 신뢰구간을 계산할 때 요구된다. 본 논문에서는 비중심t분포의 누적함수 계산에 신경망 이론을 적용하였다. 신경망은 다 층 퍼셉트론이며 학습과정은 역전파 학습알고리즘이다. Fisher가 제시한 확률값과 신 경망이론에 의하여 계산한 결과를 비교하였다.

• 한국멀티미디어학회논문지
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• 제8권9호
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• pp.1187-1194
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• 2005

본 논문에서는 영상의 공간적 축소방법을 이용한 새로운 영상의 콘트라스트 향상기법을 제안하였다. 제안된 알고리즘은 축소된 영상을 생성하여 콘트라스트 향상을 위한 누적 분포함수(CDF: Cumulative Distribution Function)의 계산량을 감소시키고 하드웨어의 복잡성을 줄였다. 제안된 방식으로 처리한 영상은 향상된 콘트라스트 결과를 얻을 수 있었다. 제안된 방식에 의한 처리 결과와 원 영상의 화질 평가를 위하여 시각적 검증과 히스토그램 표준편차를 도입하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권6호
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• pp.3188-3207
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• 2017

In this paper, we propose an image enhancement algorithm to improve license plate extraction rate in various environments (Day Street, Night Street, Underground parking lot, etc.). The proposed algorithm is composed of image enhancement algorithm and license plate extraction algorithm. The image enhancement method can improve an image quality of the degraded image, which utilizes a histogram information and overall gray level distribution of an image. The proposed algorithm employs an interpolated probability distribution value (PDV) in order to control a sudden change in image brightness. Probability distribution value can be calculated using cumulative distribution function (CDF) and probability density function (PDF) of the captured image, whose values are achieved by brightness distribution of the captured image. Also, by adjusting the image enhancement factor of each part region based on image pixel information, it provides a function that can adjust the gradation of the image in more details. This processed gray image is converted into a binary image, which fuses narrow breaks and long thin gulfs, eliminates small holes, and fills gaps in the contour by using morphology operations. Then license plate region is detected based on aspect ratio and license plate size of the bound box drawn on connected license plate areas. The images have been captured by using a video camera or a personal image recorder installed in front of the cars. The captured images have included several license plates on multilane roads. Simulation has been executed using OpenCV and MATLAB. The results show that the extraction success rate is more improved than the conventional algorithms.

• 대한금속재료학회지
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• 제46권9호
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• pp.554-562
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• 2008

The distribution and prediction interval for the misorientation angle of grain boundary at which $Cr_2N$ was precipitated during heating at $900^{\circ}C$ for $10^4$ sec were newly estimated, and followed by the estimation of mathematical and median rank methods. The probability density function of the misorientation angle can be estimated by a statistical analysis. And then the ($1-{\alpha}$)100% prediction interval of misorientation angle obtained by the estimated probability density function. If the estimated probability density function was symmetric then a prediction interval for the misorientation angle could be derived by the estimated probability density function. In the case of non-symmetric probability density function, the prediction interval could be obtained from the cumulative distribution function of the estimated probability density function. In this paper, 95, 99 and 99.73% prediction interval obtained by probability density function method and cumulative distribution function method and compared with the former results by median rank regression or mathematical method.

• 조명전기설비학회논문지
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• 제22권10호
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• pp.49-55
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• 2008

본 논문은 확률분포를 이용하여 전력설비의 기대여명을 산출하는 방법을 제안한다. 전력설비의 기대여명이란 해당 설비의 잔존수명으로, 기대여명은 전력시스템의 보수계획, 설비교체계획, 신뢰도 평가에 유용하게 이용될 수 있다. 본 논문에서는 각 운전년수별로 향후 운전가능년수에 대한 누적확률을 계산하고, 계산한 누적확률로 누적확률분포함수모델의 모수를 결정한 후, 모델함수의 평균값을 구하여 기대여명을 산정한다. 제안한 방법에서는 정립한 누적확률분포함수모델을 이용하여 기대여명 뿐만 아니라, 향후 특정 운전년수에 이르기 위한 기대확률까지도 쉽게 구할 수 있다. 제안한 방법은 우리나라 복합화력 발전소 발전기의 기대여명 추정에 적용하여 그 효용성을 입증하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제23권4호
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• pp.453-461
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• 1999

The estimation of fatigue life at the design stage is very important in order to arrive at feasible and cost effective solutions considering the total lifetime of the structure and machinery compo-nents. In this study the practical procedure of prediction of fatigue life by use of cumulative damage factors based on Miner-Palmgren hypothesis and probability density function is shown with a $135,000m^3$ LNG tank being used as an example. In particular the parameters of Weibull distribution taht determine the stress spectrum are dis-cussed. At the end some of uncertainties associated with fatigue life prediction are discussed. The main results obtained from this study are as follows: 1. The practical procedure of prediction of fatigue life by use of cumulative damage factors expressed in combination of probability density function and S-N data is proposed. 2. The calculated fatigue life is influenced by the shape parameter and stress block. The conser-vative fatigue design can be achieved when using higher value of shape parameter and the stress blocks divded into more stress blocks.

• 대한전기학회논문지:전력기술부문A
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• 제48권3호
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• pp.177-183
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• 1999

This paper presents how to evaluate the transformer damage caused by reclosing scheme at the distribution substation. We describe a quantitative relationship between the reclosing scheme and the number of fault current flowing through transformer wsing the probability of a reclosing success/failure. The transformer damage from reclosing scheme is presented using a weight function and a damage function. A weight function is associated with the number of reclosing attempts and the reclosing deadtime to consider cumulative stress caused by reclosing scheme. A damage function is associated with a transformer impact ratio and a transformer functional life. In the case study, the transformer damage is simulated for the probability of a reclosing success. And the evaluation of transformer damage using KEPCO's operation data is performed.

• 한국항행학회논문지
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• 제15권2호
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• pp.234-240
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• 2011

본 논문에서는 다수의 지상국을 이용하여 얻은 FDOA(Frequency Difference of Arrival) 측정값을 통해서 UAV(Unmanned Aerial Vehicle; 무인항공기) 추적 알고리즘의 이론적 경계인 CRLB(Cram$\acute{e}$r-Rao Lower Bound)를 분석하였다. 첫째로 FDOA 측정값을 시간을 두고 모았을 때 CRLB에 주는 영향을 관찰하였고, 둘째로 지상국이 일정한 범위 안에서 무작위적 위치를 가질 때 그 범위에 따른 FDOA의 측정값이 어떤 특성을 갖는지 확인할 수 있었다. 또한 CRLB의 크기를 측정하여 CCDF(Complementary Cumulative Distribution Function)로 나타내어 성능을 비교, 분석하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2814-2818
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• 2000

This paper describes an image processing algorithm capable of recognizing the road lane using a CDF (Cumulative Distribution Function). which is designed for the model function of the road lane. The CDF has distinctive peak points at the vicinity of the lane direction because of the directional and positional continuities of the lane. We construct a scatter diagram by collecting the edge pixels with the direction corresponding to the peak point of the CDF and carry out the principal axis-based line fitting for the scatter diagram to obtain the lane information. As noises play the role of making a lot of similar features to the lane appear and disappear in the image we introduce a recursive estimator of the function to reduce the noise effect and a scene understanding index (SUI) formulated by statistical parameters of the CDF to prevent a false alarm or miss detection. The proposed algorithm has been implemented in a real time on the video data obtained from a test vehicle driven in a typical highway.