• 지질공학
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• 제4권2호
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• pp.187-206
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• 1994

전산모형시험을 통하여 고해상도 해양반사파 탐사를 위한 최적 장비구성과 자료획득변수를 결정하였다. 조사선 온누리호에 탑재된 각기 다른 6종류의 독립 에어건과 1쌍의 cluster에 대하여 시간 및 주파수 영역에서 분석한 원거리장 파형특성은 내부용적 $2.46{\ell}$의 슬리브건 2개로 구성된 cluster를 2m 정도의 깊이에서 발파할 경우에 고해상도 탐사시 적합한 원거리장 파형이 발생될 수 있음을 보인다. 온누리호의 12채널 스트리머는 96채널 스트리머와 비교할 때, 신호대 잡음비가 다소 낮은 문제가 있으나, 높은 수직 및 수평 해상도를 얻을 수 있어 천부 반사파탐사에 적합한 것으로 분석된다. 기타 획득변수는, 대상심도, 주파수범위, 에어건 내부용적, 수신 채널수, 콤프세샤 용량 등 제반요소를 고려할 때, 기록시간 1m, 샘플간격 1ms, 발파간격 3.125m 혹은 6.25m가 적당한 것으로 판단된다.

• 대한토목학회논문집
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• 제26권6D호
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• pp.1019-1023
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• 2006

DEM에 기초한 경사정보는 도시계획, 조경, 도로설계분야는 물론 강우유출 및 토사유실평가와 같은 수자원분야에서도 매우 유용하게 활용된다. DEM에서 추출한 경사도의 해상도는 응용분야 및 모델링의 종류에 따라 다양하게 결정될 수 있으며, 특히 해상도가 낮아질수록 수평거리가 증가하기 때문에 경사도는 감소하는 특징을 갖는다. 본 연구에서는 해상도에 따른 경사정보의 손실을 개선하고자 유량공식과 Manning의 유속공식을 조합한 경사도 평가기법을 제안하였으며, 토사유실모델의 지형인자를 계산하는데 활용하였다. 적용결과 기존의 경사도 평가기법을 이용한 지형인자는 34.8%의 오차를 나타낸 반면, 조합방법에 의한 경사도를 활용한 경우에는 12.6%로 비교적 낮은 오차특성을 확보할 수 있었다. 또한 지형특성에 따른 영향을 평가하기 위해, 유역내 상 중 하류 지역을 선정하여 조합방법에 의한 효용성을 평가한 결과, 조합방법이 기존방법에 비해 개선된 결과를 보였다. 따라서 조합방법에 의한 경사도 평가기법은 강우유출모델과 같은 수자원분야에서 해상도 변화에 따른 경사정보의 손실을 효과적으로 개선할 수 있을 있으리라 판단된다.

• Journal of applied mathematics & informatics
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• 제7권2호
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• pp.629-640
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• 2000

this paper present an efficient line-drawing algorithm that reduces the amount of space required, Because of its efficiency , this line-drawing algorithm is faster than the Bresenham algorithm or the recursive bisection method. this efficiency was achieved through a new data structure; namely , the modified segment tree (MST). Using the modified segment tree and the distribution rule suggested in this paper, we dra lines without generating the recursive calls used in [3] and without creating the binary operation used in [4]. we also show that line accuracy improves in proportion to the display resolution . In practice, we can significantly improve the algorithm's performance with respect to time and space, This improvement offer an increase in speed, specially with lines at or near horizontal, diagonal. or vertical ; that is, this algorithm requires the time complexity of (n) and the space complexity O(2k+1), where n is the number of pixels and k is a level of the modified segment tree.

• 한국정보통신학회논문지
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• 제14권3호
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• pp.621-627
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• 2010

본 논문에서는 SVC 복호화기에서 각 계층간 Inter layer 업-샘플링을 효과적으로 구현하기 위한 하드웨어 구조를 제안한다. 제안하는 구조에서 수직, 수평 방향 업-샘플링을 위한 register bank와 보간 모듈이 설계된다. 제안 구조를 사용하여 SRAM 메모리가 감소되고 JSVM과 비교해서 약 41%의 메모리 밴드위스가 감소되었다.

• Wind and Structures
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• 제10권4호
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• pp.315-346
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• 2007

A preceding companion article introduced the slot jet approach for large-scale quasi-steady modelling of a downburst outflow. This article extends the approach to model the time-dependent features of the outflow. A two-dimensional slot jet with an actuated gate produces a gust with a dominant roll vortex. Two designs for the gate mechanism are investigated. Hot-wire anemometry velocity histories and profiles are presented. As well, a three-dimensional, subcloud numerical model is used to approximate the downdraft microphysics, and to compute stationary and translating outflows at high resolution. The evolution of the horizontal and vertical velocity components is examined. Comparison of the present experimental and numerical results with field observations is encouraging.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1446-1449
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• 2005

The purpose of this study is the real-time shape measurement of three-dimensional object by using color coded information. The paper relates to non-contact optical measurements of surface profiles or displacements, because of optical measurement systems are advantageous over using mechanical sensing, their relatively high speed and non-destructive capabilities. Therefore is particularly useful for three dimensional sensing which requires high horizontal and vertical resolution of measurements over a wide range thereof. Each a red, blue, green by using a inherence colors of hue value are good point.

• 한국환경과학회지
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• 제7권6호
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• pp.817-825
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• 1998

A three-dimensional ecosystem model is applied to the Suyoung Bay, located at the southeastern part of Korea, to study of the material distribution in the time scale of several tens days. The model has included of the DIN(Dissolved Inorganic Nitrogen), DIP(Dissolved Inorganic Phosphate), phytoplankton, zooplankton and detritus, and also was coupled with the physical processes. The spatial distribution of chlorophyll-a and primary productivity in the model is determined by the physical and chemical-biological parameters. The horizontal distributions of the DIN, DIP and chlorophyll-a are decreased from the coast to the off-shore, though the nutrients show some more complicated pattern than the chlorophyll-a. The nutrient contents in the off-shore are low, and thus a relatively low productivity(chlorophyll-a) are presented. On the whole, the distribution of the results of model are smoother than the observed ones and some small scale variation in the observed data cannot be reproduced by the model due to the resolution limits of model. However, the basic pattern and the quantitavities has been reproduced by the model well.

• 대기
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• 제21권4호
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• pp.471-480
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• 2011

This study investigates the characteristics of surface wind in North Korea using mesoscale model WRF. Hourly wind fields were simulated for one year representing mean characteristics of an 11-years period from 1998 to 2008. The simulations were performed on a nested grid from 27 km to 1 km horizontal resolution. The simulated wind map at 10 m above ground level is verified with 27 surface observations. Statistical verification skill score indicates that wind speed tends to overestimate in surface layer. The average RMSE value of the simulated wind speed is around $2.8ms^{-1}$. Wind map in North Korea showed that strong wind speed is distributed in the mountainous and western coastal region. The results of this wind mapping study contribute for the founding of wind energy potential location.

• 한국유체기계학회 논문집
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• 제10권4호
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• pp.47-54
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• 2007

Simultaneous 3-D LDV measurements of the in-cylinder flows of three different engine setups were summarized for the quantification of the flow characteristics in each vertical or horizontal plane, and in entire cylinder volume. The ensemble averaged-velocity, tumble and swirl motions, and turbulent kinetic energy during the intake and compression strokes were examined from the measured velocity data (approximately 2,000 points for each engine setup). The better spatial resolution of the 3-D LDV allows measurements of the instantaneous flow structures, yielding more valuable information about the smaller flow structures and the cycle-to-cycle variation of these flow patterns. Tumble and swirl ratios, and turbulent kinetic energy were quantified as planar and volumetric quantities. The measurements and calculation results were animated for the visualization of the flow, and hence ease to analysis.

• Journal of Advanced Marine Engineering and Technology
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• 제38권8호
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• pp.1000-1003
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• 2014

There are 70 vertical and 70 horizontal correctors for Pohang Light Source. Until mid of 2000, power supplies for these correctors were based on 1990's technology, so the global orbit feedback system was not possible with poor 12 bit resolution. A new task force team was assembled to develop new power supplies with BESSY type DAC cards. After the project, two vertical correctors in each lattice were connected with new power supplies, and the global orbit feedback was available within the accuracy of 5 microns. However, this replacement was not enough to satisfy the beam stability requirement of 2 microns for PLS. We have launched another power supply design based on all digital technology. This attempt was completed within a year, and 80 units were assembled in house. Currently, the global orbit feedback system is running successfully with new digital power supplies and the compensation of chamber motion due to the thermal load by using digital displacement transducers attached on each BPMs.