• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.11
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• pp.41-48
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• 2005

The crosstalk effects that can be observed in the very dee submicron semiconductor chips are due to the coupling capacitances between interconnect lines. The accuracy of the full-chip timing analysis is determined by the accuracy of the estimated propagation delays of cells and interconnects within the chip. This paper presents a CMOS cell driver model and delay calculation algerian capturing the crosstalk effects due to the coupling capacitances. The proposed model and algorithm were implemented in a delay calculation program and used to estimate the propagation delays of the benchmark circuits extracted from a chip layout. We observed that the average discrepancy from HSPICE simulation results is within $1\%$ for the circuits with a victim affected by $0\~10$ aggressors.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.174-177
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• 2003

본 논문에서는 AC PDP의 유지방전구간에서의 인가전압에 따른 방전전류, 공간전압, 벽전하 등의 변화를 새로운 AC PDP를 위한 등가회로모델을 사용하여 효율적이고 간편하게 시뮬레이션 한 결과를 소개한다. 벽전하의 정확한 분석은 안정적이고 효율적인 AC PDP의 구동 방법을 개발하기 위해 계속 연구, 보고 되어 왔지만, 인가되는 전압의 변화에 따른 시간적인 셀 내부의 변화를 빠르고 편리하게 분석하고 이해하는데 효과적인 방법은 제시되지 못하였다. 본 논문에서는 AC PDP의 전극간 물리적인 특성을 고려하여 3개의 직렬 커패시터와 1개의 병렬 커패시터, 2개의 싸이리스터를 사용하여 AC PDP를 위한 등가회로모델을 구성하여 제시하였다. 제안된 등가회로모델은 SPICE와 같은 표준 회로시뮬레이션 툴에 손쉽게 적용가능하며, 이러한 방법으로 분석된 패널내의 전류, 공간전압, 벽전하의 동특성을 소개하였다. 등가회로모델을 이용한 시뮬레이션 결과는 실험을 통한 측정 결과와 비교하여 그 정확성을 검증하였다. 인가전압의 시간적 변화의 따른 유입전류 및 셀 내의 전압 및 전하의 분포를 손쉽고 정확하게 시뮬레이션 할 수 있는 본 AC PDP의 등가회로모델은 AC PDP의 특성을 이해하는 데에 중요한 도구가 될 것이며 효율적인 구동 방식의 개발 및 분석 등에 널리 활용될 수 있을 것이다.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.1 s.24
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• pp.67-72
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• 2007

A model for predicting potentials of land erosion and deposition over a natural basin was developed based on the mass balance principle. The program was developed based on sediment mass balance principle for each cell in a GIS. Sediment yield from a cell was estimated with RUSLE. The outflow sediment from a cell was calculated by multiplying the sediment yield of the cell by the sediment delivery ratio (SDR) of the cell. The outflow sediment from the upstream cell becomes the incoming sediment of the downstream cell. Therefore the erosion and deposition potential of each cell could be determined from the sediment mass balance i.e., the difference between the incoming and outflow of sediments of each cell. The developed model was validated by comparing the predicted sediment yields for three basins with measured data.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.81-81
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• 2017

최근 발생하는 태풍 또는 국지성호우는 단기간에 많은 양의 강우를 동반하고 있으며, 이로인한 내수침수 및 외수범람 피해가 빈번히 발생하고 있다. 이와 같은 홍수피해를 저감하기 위한 하나의 대책으로 내수 또는 외수로 인한 피해를 미리 예측하고 대비하는 방법이 필요하다. 피해를 미리 예측하기 위한 기존의 모델들은 지표유출, 지하유출, 침투, 증발산 등 다양한 강우-유출 알고리즘에 의해 홍수범람모의를 분석하게 된다. 따라서 그 모의시간이 길게 나타나 재난상황을 대처하는 데 문제가 있다. 본 연구에서는 홍수로 인한 제내지의 침수 확산 경로 빠른 시간 안에 모의하기 위하여 여러 가지 알고리즘을 단순화시킨 홍수범람 모형을 개발하였다. 개발된 분포형 홍수범람 모형인 SIMOD(Simplified Inundation MODel)는 홍수가 발생된 시점에서 그리드화된 주변셀로의 홍수전의를 위하여 주변셀과의 경사를 이용하여 차등 분배하는 다중흐름방향법(Multi Direction Method, MDM)과, 하나의 낮은 고도의 셀에서 수위가 높아져 인접셀보다 수위가 증가하면 그 수위는 인접 셀들과 균등해 진다는 가정인 평수가정법(Flat-Water Assumption, FWA)인 두 가지 알고리즘을 이용한다. 개발된 모형의 적합성을 확인하기 위하여 상용 모형인 FLO-2D를 이용하여 각 모의시간별 침수면적과 모형의 구동시간을 비교하였다. 비교결과 초기 1시간을 제외하고 홍수피해 면적이 10% 전후로 나타나 SIMOD의 적용성이 확인되었다. 모의 구동시간의 경우 32시간 모의시 SIMOD는 10분 안에 결과가 나오는 반면 FLO-2D는 1시간 이상 소요되는 것으로 나타났다. 또한 대피계획을 수립하기 위하여 제방붕괴시나리오를 이용한 제내지 침수모의를 실시하였다. 대상지역은 금호강하류 성서산업단지 유역으로 계획홍수위는 200년 빈도 홍수위를 기준으로 하였으며 폭 35m, 높이 7m의 제방파제로 인한 외수위 유입을 가정하여 제내지의 시간별 침수면적 모의하였다. 모의된 결과를 이용하여 시간대별 대피경로를 산정함으로써 홍수로 인한 대피 계획 수립에 적용 가능함을 확인하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.47-52
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• 2014

A simple RC circuit model of large-scale touch screen panels is developed and the frequency range of the RC model is analyzed. 2D EM simulation results of a single touch cell are cascaded for a 23 inch touch panel using a circuit simulator, and the shortest and longest channels of the full panel are modeled with a 5-element RC circuit. The 5-element RC circuit can model the touch screen panel upto 130 kHz with the channel phase error of $10^{\circ}$. 7-element RC circuit model is also proposed and the frequency range for the channel phase error of $10^{\circ}$ is extended to 200 kHz.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.9
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• pp.28-35
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• 2015

In this paper, we propose to identify redundant power states of high-level power model based on clock gating enable signals(CGENs) using dependencies of Boolean functions and structural dependencies of clock gating cells. Three functional dependencies between two CGENs, namely equvalence, inversion, and inclusion, are used. Functions of CGENs in a circuit are represented by binary decision diagrams (BDDs) and the functional relations are used to reduce the number of power states. The structural dependency appears when a clock gating cell drives another clock gating cells in a circuit. Automatic dependency checking algorithm has been proposed. The experimental results show the average number of power state is reduced by 59%.

• Journal of Navigation and Port Research
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• v.30 no.1 s.107
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• pp.105-111
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• 2006

A LMTT (Linear Motor-based Transfer Technology) is a horizontal transfer system for the yard automation This system is based on PMLSM (Permanent Magnetic Linear Synchronous Motor) that consists of stator modules on the rail and shuttle car. In this research, the kriging interpolation method using sequential sampling is utilized to find the optimum design of a mover in LMTT. The design variables are considered as the transverse, longitudinal and wheel beam's thicknesses. The objective function is set up as weight, while the constant functions are set up as the stresses generated by four loading conditions. The optimum results obtained by the suggested method are compared with those determined by the GENESIS.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.3
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• pp.189-196
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• 2018

Propeller performance measurement system for high altitude UAV was designed and applied to the wind tunnel test for 2 propeller models with a diameter around 1 m. Mechanical power of the propeller was directly measured by using the torque sensor installed on the rotating axis. The thrust of whole operation body including the propeller was measured by thrust road cell. The guide rail system was suggested to reduce the weight influence of operation body on the thrust road cell. The influence of each measured variables on the aerodynamic coefficients was studied with the repeatability and uncertainty analysis. This analysis result shows that the accuracies of the road cell and the wind velocity were major factors for the thrust coefficient. Propeller performance with typical RPM was measured with various wind speeds and the test results was summarized by performance coefficients for 5 different RPM.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.8
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• pp.662-669
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• 2012

The effect of aspect ratio (AR) on the aerodynamic characteristics of a flapping wing was examined to analyze the design parameters of an insect-based MAV. The experimental model constructed with 4-bar linkages was operated in a water tank with the condition of a low Reynolds number. A water-proof micro-force load cell was fabricated and installed at the root of the wing which is made of a plexiglas. The wing shapes were based on the planform of a fruit fly wing. The ARs selected were 1.87, 3.74 and 7.48 and the Reynolds number was fixed at $10^4$. For AR=1.87 and 3.74, distinct lift peaks which indicate unsteady effects such as 'wake-capture' were observed at the moment of the start of the wing-stroke. However, for AR=7.48, no unsteady effects were observed. These phenomena were also observed in the delayed rotation case. The results indicate that a larger AR provides better aerodynamic performance for the insect-based flapping wing which can be applied in MAV designs.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.5
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• pp.81-92
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• 2013

The satellite includes many release mechanisms such as solar array deployment, antenna deployment, cover to protect contamination in scientific equipment, pyro value of the propulsion subsytem, and bypass device in Li-Ion cell module. A drive the initiators is a critical to the successful mission because the initiators of release mechanism driving by the pyrotechnic circuit is operated in single short. The pyrotechnic circuit has to provide switching network for safety. A typical switching network has defect consisting of high current rating fire switch to handle switching transient current during fire the initiator. The pyrotechnic circuit is required some form of power conditioning to reduce the peak power demanded from the bus if the initiators are to be fired from the main bus. This paper design a pyrotechnic circuit synchronized to the fire-command to activate the fire switch to overcome use high current rating fire switch to handle switching transient current during fire the initiator. The pyrotechnic circuit provides a current limited widow pulse for fire current synchronized to the fire-command to insure that fire switch will only carry the current but never switch it. The current limited widow pulse for fire current can be possible to use low current rating and light mass switch in switching network. The current limit function in the pyrotechnic circuit reduces supply voltage to initiator and provides the effect of power conditioning function to reduce peak bus power. The pyrotechnic circuit to apply satellite development on geostationary orbit is verified the function by test in development model.