• Journal of the Korean Society of Radiology
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• v.7 no.2
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• pp.137-143
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• 2013

This study presents comparison results between axial and spiral scanning in the head and chest region with 64 MDCT to evaluate organ doses in infants and toddlers, who are more radiosensitive to radiation than adults and rise in the number of CT examinations, during CT scanning. Organ doses were significantly lower in spiral scanning than axial scanning regardless of scanned regions. The average organ dose for the chest scan using pitch of 1.355 was found to be significantly higher(average -12.03%) than for the other two pitch settings(0.525 and 0.988) in the spiral scanning mode compared with the axial one. Organ doses in the spiral scanning mode were lower by average 20.54% than the axial scanning mode. The results of the study that evaluated organ doses with an anthropomorphic phantom will help to demonstrate the result values of Monte Carlo simulations and make a contribution to more accurate evaluations of organ doses in toddlers undergoing a CT examination.

• 주류공업
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• v.12 no.1
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• pp.39-43
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• 1992

• 한국해양학회지
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• v.30 no.3
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• pp.170-183
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• 1995

Eddies and surface current field in the southwestern part of the East Sea were investigated using satellite-tracked drifters, CTD, and ADCP from November 1992 to September 1993. Trajectories of surface drifters provided information for the first time on the meandering motion of the East Korean Warm Current in the Ullung Basin (referred as UB) and clearly indicated the existence of cyclonic and anticyclonic eddies of various scales. Anticyclonic eddies persisting for a relatively long period were observed in UB and the southwestern corner of the Northern (Japan) Basin (SNB), while a cyclonic eddy was found in the coastal area between Sokcho and Donghae during the summer. Analysis shows that the eddy in UB behaved as a stationary eddy at least during the observation period and the cyclonic eddy was closely related to the existence of a cold water mass. The anticyclonic eddy in SNB was larger than that in UB, but much elongated in shape. The eddy in UB is characteristic of major and minor axes of about 120 and 70 km, revolution period of 13.6 days, mean swirl velocity of about 24 cm/s, and mean eddy kinetic energy of 392 cm$\^$2//s$\^$2/. The eddy in SNB is described as follows; major and minor axes of 168 and 86 km, period of 14.9 days, mean swirl velocity of 29 cm/s and mean eddy kinetic energy of 629 cm$\^$2//s$\^$2/. The mean translational speed is about 3 cm/s for both eddies. The agreement of the surface current pattern in UB observed by ADCP with the geostrophic flow pattern may suggest that the eddy in UB was nearly in geostrophic balance. The eddy was found to be strongly bottom-controlled.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.722-727
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• 2009

The technology of distinguishing human motion states is required in the areas of measuring and analyzing biosignals changing according to physical activities, diagnosing sleep disorder, screening the effect of treatment, examining chronic patients' kinetic state, prescribing exercise therapy, etc. The present study implemented a fuzzy inference system based on fuzzy rules that distinguish human motion states (tying, sitting, walking, and running) by acquiring and processing data of LAA, TAA, L-MAD, and T-MAD using ADXL202AE of Analog Devices embedded in an armband. The membership degree and fuzzy rules in each area of input (LAA, TAA, L-MAD, and T-MAD) and output (tying, sitting, walking, and running) data used here were determined using numeric data obtained from experiment. In the results of analyzing data for simulation generated in order of tying$\rightarrow$walking$\rightarrow$running$\rightarrow$tying, the sorting rate for motion states tying, sitting, walking, and running was 100% for each motion.

• The Transactions of the Korea Information Processing Society
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• v.3 no.6
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• pp.1646-1657
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• 1996

This paper presents a color transformation method based on a uniform color image model. Firstly, color variation factors are grouped into identical (multiplicative) factor and independent(additive) one for the color model, and they are modelled by the Gaussian function. The shape of a color cluster in (R, G, B) feature space is an ellipsoid whose elongated major axis correspond to the direction of mean vector. Secondly, the transformation of a color cluster using the model is studied. A transformation method for three dimensional coordinated is described. The proposed method is applied to artificial and natural color images. By the result of experiments, the elongated major axis of each cluster making up the transformed color image aggress with the direction of its mean vector.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.608-610
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• 2009

지열 분포에 관련된 지질구조의 특성을 파악하기 위하여 지온경사, 지열류량 자료와 인접한 선구조의 방향성에 대한 상관성 분석을 실시하였다. GIS를 이용하여 지열정보데이터베이스에서 발췌한 209개 지온경사 자료와 218개 지열류량 자료에 대하여 전국 광역단열도로부터 가장 인접한 선구조를 추출하고 10도 간격의 방향별 지온경사 및 지열류량 자료 빈도 및 평균값을 그래프에 도시하였다. 인접 선구조의 방향별 지온경사 평균은 $N30^{\circ}{\sim}40^{\circ}W$, $N10^{\circ}{\sim}20^{\circ}E$ 방향에서 $58.9^{\circ}C/km$, $54.9^{\circ}C/km$로 가장 높았고, 인접 선구조의 방향별 지열류량 평균은 $N80^{\circ}{\sim}90^{\circ}W$, $N50^{\circ}{\sim}60^{\circ}W$ 방향에서 98.71 $mW/m^2$, $98.70mW/m^2$로 가장 높았다. 각 선구조 상의 좌표들을 이용하여 지열류량 분포도에서 지열류량 값을 추출한 결과 $N10^{\circ}W{\sim}N40^{\circ}E$, $N60^{\circ}{\sim}70^{\circ}W$, $N50^{\circ}{\sim}60^{\circ}E$ 방향의 지열류량 높은 것으로 나타났다. 결과적으로 지온경사와 지열류량 자료에 대한 인접 선구조의 방향은 북북동, 북서, 서북서 방향이 우세한 것으로 나타났다. 이는 우리나라 조구조 운동과 관련한 단층, 절리 등의 단열구조의 우세 방향과 잘 일치하는 것으로 해석된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.338-347
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• 2005

In this paper, a decimation-in-time search direction algorithm for displacement prediction of moving object is proposed. The initialization of the proposed algorithm for moving direction prediction is performed by detecting moving objects at sequential frames and by obtaining a moving angle and a moving distance. A moving direction of the moving object at current frame is obtained by applying the decimation-in-time search direction mask. The decimation-in-tine search direction mask is that the moving object is detected by thinning out frames among the sequential frames, and the moving direction of the moving object is predicted by the search mask which is decided by obtaining the moving angle of the moving object in the 8 directions. to examine the propriety of the proposed algorithm, velocities of a driving car are measured and tracked, and to evaluate the efficiency, the proposed algorithm is compared to the full search algorithm. The evaluated results show that the number of displacement search times is reduced up to 91.8$\%$ on the average in the proposed algorithm, and the processing time of the tracking is 32.1ms on the average.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.119-121
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• 2022

In this paper, we will make a model that finds optimal phase for each crossroad. When the traffic volume, traffic capacity, and the lane width of every direction is given for each crossroad, we aim to find the most efficient phase. We established an evaluation function that evaluates the efficiency of each phase using the values of the average waiting time in one direction, the average delay time, the standard deviation of the delay time, and the average delay time in each direction. The time allocation to optimize a phase pattern can be obtained by using the gradient decent method. Through this research, we hope to decrease the waiting time in transporation, thus improving the overall traffic condition in cities.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.434-438
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• 2005

본 연구에서는 개수로 흐름에서 전단속도의 분포를 조사하였다. 이를 위해 직사각형 개수로 흐름과 복단면 개수로 흐름에 대한 DNS 자료를 이용하였으며, 계산된 전단속도는 기존의 실험자료 및 수치해석결과와 비교$\cdot$분석되었다. 평균흐름장에서는 직사각형 개수로 흐름의 경우, 자유수면 부근에서 내측이차흐름이 발생하는 것을 볼 수 있었으며, 복단면 개수로 흐름에서는 주수로와 홍수터의 접합부 부근에서 쌍와가 생성되는 것으로 나타났다. 이차흐름의 최대크기는 체적평균된 주흐름방향 유속의 약 $5\%$로서, 직사각형 개수로 흐름에서 발생되는 것보다 더 강하다는 것을 알 수 있었다. 이러한 이차흐름의 영향으로 주흐름방향 평균유속의 등속선이 편향된 것으로 나타났다. 본 DNS에서 전단속도가 최대값을 갖는 지점은 직사각형 개수로 흐름의 경우 자유수면이며, 복단면 개수로 흐름의 경우 접합부인 것으로 나타났다. 이는 기존 LES 결과와 동일하지만, 실험연구와는 다른 결과이다. 접합부에서 이러한 차이를 보이는 이유는 실험에서 마찰속도를 산정하기 위해 사용하는 방법의 부적합성에 있는 것으로 나타났다.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.329-334
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• 1997

기포막 제한 및 기포 군집 이론에 의한 해석적 접근을 통해 축방향 출력분포가 임계열속에 미치는 영향을 파악하고, 이를 근거로 임계열속 발생지점에서의 엔탈피 변화를 고려하여 축방향 출력분포에 따른 임계열속 예측치 보정 모델을 개발하였다. 제안된 모델의 검증을 위해 cosine 형태의 축방향 출력분포를 갖는 임계열속 측정치와 비교하였으며, 그 결과 제안된 모델은 측정치에 대해 평균 1.0072, 표준편차 9.98%의 예측 성능을 나타냈다.