• 반도체디스플레이기술학회지
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• 제18권3호
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• pp.1-6
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• 2019

Foreground/background segmentation in video sequences is often one of the first tasks in machine vision applications, making it a critical part of the system. In this paper, we present an improved sample-based technique that provides robust background image as well as segmentation mask. The conventional multiple interval sampling (MIS) algorithm have suffer from the unbalance of computation time per frame and the rapid change of confidence factor of background pixel. To balance the computation amount, a random-based pixel update scheme is proposed and a spatial and temporal smoothing technique is adopted to increase reliability of the confidence factor. The proposed method allows the sampling queue to have more dispersed data in time and space, and provides more continuous and reliable confidence factor. Experimental results revealed that our method works well to estimate stable background image and the foreground mask.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제2권1호
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• pp.27-34
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• 2013

배경제거는 동영상의 내용을 자동으로 분석하기 위한 매우 중요한 기술의 하나로 움직이는 객체를 검출하고 추적하기 위한 핵심 기술이다. 본 논문에서는 배경 모델과 함께 배경 영상을 제공하는 새로운 샘플링 기반의 배경제거 알고리즘을 제안한다. 제안된 방법에서는 움직임이 빠른 객체와 느린 객체를 동시에 처리하기 위해 다중 구간 샘플링 기법을 이용하여 배경 모델을 생성한다. 이러한 다중 구간 배경 모델들로부터 최선의 배경 모델을 만들기 위해 "신뢰도"를 사용한 것이 본 논문의 특징이다. 배경 제거 분야에서 다양한 모델을 병합하여 하나의 모델을 만들기 위해 신뢰도를 정의하여 사용한 경우는 현재까지 보고되지 않았다. 실험을 통해 제안된 방법이 다양한 속도의 객체가 존재하고 시간에 따른 그림자의 이동과 같은 환경 변화가 있는 응용에서도 안정적인 결과를 나타내는 것을 알 수 있었다.

• 통합자연과학논문집
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• 제5권3호
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• pp.151-156
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• 2012

Because of the equivalence between control chart procedures and hypothesis testing, we propose to use likelihood ratio test (LRT) statistic $Z_i^2$ as the multivariate control statistic for simultaneous monitoring means of the multivariate normal process. Properties and comparisons of the proposed control charts are explored and conducted for matched fixed sampling interval (FSI) and variable sampling interval (VSI) with two sampling interval charts. The result of numerical comparisons shows that EWMA chart with two sampling interval procedure is more efficient than the corresponding FSI chart for small or moderate changes. When large shift of the process has occurred, we also found that Shewhart chart is more efficient than EWMA chart.

• 반도체디스플레이기술학회지
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• 제19권2호
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• pp.31-36
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• 2020

Most of the background subtraction algorithms show good performance in static scenes. In the case of dynamic scenes, they frequently cause false alarm to "temporal clutter", a repetitive motion within a certain area. In this paper, we propose a robust technique for the multiple interval pixel sampling (MIS) algorithm to handle highly dynamic scenes. An adaptive threshold scheme is used to suppress false alarms in low-confidence regions. We also utilize multiple background models in the foreground segmentation process to handle repetitive background movements. Experimental results revealed that our approach works well in handling various temporal clutters.

• 통합자연과학논문집
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• 제5권4호
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• pp.246-252
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• 2012

Multivariate cumulative sum (CUSUM) control charts for simultaneously monitoring both means and variances under multivariate normal process are investigated. Performances of multivariate CUSUM schemes are evaluated for matched fixed sampling interval (FSI) and variable sampling interval (VSI) features in terms of average time to signal (ATS), average number of samples to signal (ANSS). Multivariate Shewhart charts are also considered to compare the properties of multivariate CUSUM charts. Numerical results show that presented CUSUM charts are more efficient than the corresponding Shewhart chart for small or moderate shifts and VSI feature with two sampling intervals is more efficient than FSI feature. When small changes in the production process have occurred, CUSUM chart with small reference values will be recommended in terms of the time to signal.

• 제어로봇시스템학회논문지
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• 제16권3호
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• pp.293-299
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• 2010

The multiple block localization method in a wide area for multiple robots using iGS is proposed in this paper. The iGS is developed for the indoor global localization using ultrasonic and RF sensors. To measure the distance between a mobile robot and a beacon, the tag on the mobile robot wakes up one beacon to send out the ultrasonic signal and measures the traveling time from the beacon to the mobile robot. As the number of robots is increased, the sampling time of localization also becomes longer. Note that only one robot can localize its own position calling beacons one by one during each of the sampling interval. This is a severe constraint for the localization of multiple robots in a wide area. This paper proposes an efficient localization algorithm for the multiple robots in a wide area which can be divided into multiple blocks. For a given block, a master beacon is designated to synchronize robots. By the access of the synchronization signal, each beacon in the selected group sends out an ultrasonic signal. When the robots in the block receive the ultrasonic signal, they can calculate their own locations based on the distances to the beacons, which are obtained by the multiplication of flight time and velocity of the ultrasonic signal. The efficiency of the algorithm is verified through the real experiments.

• Nuclear Medicine and Molecular Imaging
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• 제42권1호
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• pp.52-60
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• 2008

목적: 다중섬광결정 PET으로 얻은 데이터에 대한 여과후역투사 영상재구성 적용을 위한 사이노그램 저장과 보정 방법을 확립하고자 한다. 대상 및 방법: 검출된 PET 데이터에 대한 저장기법에 대한 연구를 수행하여 효율적 영상재구성을 위한 사이노그램 방식을 확립하였다. 히스토그램에서 사이노그램으로 데이터를 변환할 때 생기는 제반 문제들을 해결하기 위하여 데이터 표본의 최적화와 표본 불균일성 보정기법에 관한 연구를 수행하였으며, PMT간 틈새 보정을 위 한 연구를 수행하였다. 모든 데이터는 2차원 여과후역투사 알고리즘을 이용하여 재구성하였으며 보정에 따른 영상질의 향상을 평가하였다. 결과: 표본이론에 의해서 추정된 최소 표본수와 표본 불균일성 보정기법의 적용을 위한 수월성 등을 고려할 때 방사방향 표본간격이 pitch/2, 각 표본수가 120개 정도가 적절하였으며, 불균일성 보정과 틈새보정을 적용함으로서 영상왜곡과 배경잡음을 줄일 수 있었다. 결론: 다층섬광결정 PET의 FBP 영상재구성을 위하여 히스토그램 데이터를 사이노그램으로 변환하는 기법에 대한 연구가 이루어졌으며 이를 통한 고속의 2D 영상재구성이 가능할 것으로 보인다.

• International Journal of Quality Innovation
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• 제2권1호
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• pp.69-86
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• 2001

The economic design of control charts has been researched for over four decades since Duncan proposed the concept in 1956. Few studies, however, have focused attention on the economic design of a moving average (MA) control chart. An MA control chart is more effective than the Shewhart chart in detecting small process shifts [9]. This paper provides an economic model for determining the optimal parameters of an MA control chart with multiple assignable causes and two failures in the production process. These parameters consist of the sample size, the spread of the control limit and the sampling interval. A numerical example is shown and the sensitivity analysis shows that the magnitude of shift, rate of occurrence of assignable causes and increasing cost when the process is out of control have a more significant effect on the loss cost, meaning that one should more carefully estimate these values when conducting an economic analysis.

• Journal of Nutrition and Health
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• 제35권2호
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• pp.263-271
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• 2002

The purpose of this study was to determine the standard work time of dietetic staff through work sampling methodology in school flood service systems. Work measurement through work sampling methodology was conducted in five conventional, five commissary and five joint management flood service systems over two consecutive weeks in October 1999. Statistical analysis was performed on the SAS/Win 6.12 package program for Kruskal-Wallis test and multiple comparison. Observed data were satisfied with a confidence level of 95% and a confidence interval of $\pm$ 0.05. The results of this study can be summarized as follows. The actual time spent by dietetic staff members in conventional, commissary, joint-management flood servile systems was 2,394, 2,521 and 2,110 minutes per week, respectively. Transportation time of each flood service systeml and ILO allowance rate (11%) was applied. Thus, the standard work time per week of dietetic staff members in conventional, commissary, joint-management flood service systems was 2,746.14, 2,861.58 and 2,520.81 minutes, respectively. The standardized index was 1.04, 1.08 and 0.95 men in conventional, commissary, and joint-management flood service systems, respectively. Regardless of the school flood service system, those with "the duty of cooking and distribution management" had the longest labor time, while those with "duty of nutritional education" had the shortest labor time.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 창립 20주년기념 특별학술발표회
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• pp.331-332
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• 2009

We present an analysis on the quality factors of the Fourier hologram generated from multiple orthographic view images of three-dimensional object. In the analysis, we analyze both the maximum size of the reconstructed object and its spatial resolution. For the maximum size of the reconstruction, we found that the main factor is the orthographic projection angle interval. Too large projection angle interval causes overlapping in the reconstruction space domain. For the spatial resolution, there are three factors, i.e. the capturing lens array pitch which determines the spatial sampling rate of the original three-dimensional objects, the maximum orthographic projection angle, and the spatial frequency bandwidth of the object. The dominant factor is determined by the relationship between those three factors.