• 한국컴퓨터정보학회논문지
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• 제21권3호
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• pp.1-8
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• 2016

The printed circuit board (PCB) can be used only 2 layers of front and back. Therefore, the wiring line segments are located in 2 layers without crossing each other. In this case, the line segment can be appear in both layers and this line segment is to resolve the crossing problem go through the via. The via minimization problem (VMP) has minimum number of via in layout design problem. The VMP is classified by NP-complete because of the polynomial time algorithm to solve the optimal solution has been unknown yet. This paper suggests polynomial time algorithm that can be solve the optimal solution of VMP. This algorithm transforms n-line segments into vertices, and p-crossing into edges of a graph. Then this graph is partitioned into 3-coloring sets of each vertex in each set independent each other. For 3-coloring sets $C_i$, (i=1,2,3), the $C_1$ is assigned to front F, $C_2$ is back B, and $C_3$ is B-F and connected with via. For the various experimental data, though this algorithm can be require O(np) polynomial time, we obtain the optimal solution for all of data.

• 한국작물학회지
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• 제38권6호
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• pp.495-508
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• 1993

연초 종자생산의 기초자료를 얻기 위하여 임성품종과 웅성불임 품종을 공시하여 격리거리 및 이식시기에 따른 자연교잡율을 조사하였다. 1. 임성품종간의 인접재배시 자연교잡율은 평균 1.6%이었고 0.9～2.5%범위로 나타났다. 2. 임성품종과 웅성불임 게통의 인접재배시 자연교잡율은 29%로 임성품종에 비하여 현저히 높게 나타났다. 3. 이식시기따른 자연교잡율은 4월20일 이식한 처리구가 5월 5일 및 5월20일 이식한 처리구보다 현저히 높았다. 4. 격리거리에 따른 자연교잡율은 격리거리가 멀수록 낮았고 300m 격리구에서도 자연교잡이 0.8%로 나타났다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1112-1117
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• 2010

The intelligent safety system for level crossing which employs information and communication technology has been developed in USA and Japan, etc. But, in Korea, the relevant research has not been performed. In this paper, we analyze the cause of railway level crossing accidents and the inherent problem of the existing safety equipments. Based on analyzed results, we design the intelligent safety system which prevent collision between a train and a vehicle. This system displays train approaching information in real-time at roadside warning devices, informs approaching train of the detected obstacle in crossing areas, and is interconnected with traffic signal to empty the crossing area before train comes. Especially, we present the video based obstacle detection algorithm and verify its performance with prototype H/W since the abrupt obstacles in crossing areas are the main cause of level crossing accidents. We identify that the presented scheme detects both pedestrian and vehicle with good performance. Currently, we demonstrate developed railway crossing intelligence system at one crossing of Young-dong-seon line of Korail with Sea Train cockpit.

• 전력전자학회논문지
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• 제17권5호
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• pp.409-415
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• 2012

This paper presents a new software-based on-line dead-time compensation technique for a single-phase grid-connected photovoltaic (PV) inverter system. To prevent a short circuit in the inverter arms, a switching delay time must be inserted in the pulse width modulation (PWM) signals. This causes the dead-time effect, which degrades the system performance around zero-crossing point of the output current. To reduce the dead-time effect around the zero-crossing point of grid current, a harmonic mitigation of grid current is used as an additional part of the synchronous frame current control scheme. This additional task mitigates the harmonic components caused by the dead-time from the grid current. Simulation and experimental results are shown to verify the effectiveness of the proposed dead-time compensation method in the single-phase grid-connected inverter system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.724-730
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• 2011

A turnout serves to switch train from one line to another. The turnout consists of a Point which is switchs the rail to induce direction, and a Crossing which is cross over two line on the plane surface, and a Lead where is middle section in Point to Crossing. Point machine, consists of a turnout, is important facilities in railway signal, that is safety issue relates in derailment of the train. Recently, train delay and accident frequently occurred because of the turnout include in a point machine trouble of electrical and mechanical. So in order to prevent train accident the research is advanced, install of normal and reverse indication lamp in a point machine, development of adherence detector for sensing the status of adhesion between the stock rails and tongue rails etc. In this paper investigates the problem which is connected with a turnout trouble, include in a point machine, occurrence at the time of train accident, and then proposed to the safety system model in order to prevent the train accident in turnout.

• 자동차안전학회지
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• 제8권1호
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• pp.13-18
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• 2016

More than 80 percent of traffic accidents related with lane departure believed to be the result of crossing the lane due to either negligence or drowsiness of the driver. Lane-departure related accident in the highway usually involve high fatality. Even though LDWS is believed to prevent accident 25% and reduce fatalities by 15% respectively, its effectiveness in performance is yet to be confirmed in many aspects. In this study, the vehicle lateral locations relative to warning zone envelop (earliest and latest warning zone) defined in ISO standard, ECE and NHTSA regulations are compared with respect to various factors including delays, vehicle speed and vehicle heading angle with respect to the lane. Since LDWS is designed to be activated at the speed over 60 km/h, vehicle speed range for the study is set to be from 60 to 100 km/h. The vehicle heading angle (yaw angle) is set to be up to 5 degree away from the lane (abrupt lane change) considering standard for lane change test using double lane-change test specification. The TLC is calculated using factors like vehicle speed, yaw angle and reaction time. In addition, the effect of vehicle type and reaction time have been considered to assess LDWS safety.

• 한국ITS학회 논문지
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• 제7권5호
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• pp.77-89
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• 2008

자전거도로가 설치된 교차로 빛 횡단도로에서 자전거, 차량 및 보행자 간에 상충이 발생하게 된다. 이와 같이 자전거 도로와 여타 교통류가 교차되는 구간에서 자전거와 자동차, 자전거와 보행자와의 상충을 분리해주어야 하는데, 이런 방법 중 하나가 자전거전용신호라고 할 수 있다 자전거도로 시설 및 이용자 특성조사에 따르면 자전거도로가 횡단보도와 연 계하여 설치되어 있고, 자전거이용자 대부분이 횡단보도신호를 이용하고 있으며, 횡단보도시간 내에 횡단을 종료하는 것으로 조사되었다. 따라서 횡단보도와 자전거도로가 인접된 자전거횡단도로에서는 보행신호등과 연계한 운영방안 즉, 영국의 TOUCAN Crossing 형태의 적용이 제안된다. 이와 같은 자전거전용신호 운영체계는 현재 자전거횡단도로의 위치가 횡단보도와 인접하여 설치되어 있고, 대부분의 자전거이용자들이 보행신호에 따라 도로를 횡단하고 있으며, 보행선호시간동안 횡단할 수 있기 때문이다. 반면에 자전거횡단도로가 보행도로와 이격되어 설치된 경우 및 자전거의 통행속도 등을 고려하여 전용도로 형태로 자전거도로가 설치된 경우에는 차량신호와 연계한 자전거신호등 형태 (3색 등화체계)가 제안된다. 이와 같은 자전거신호등의 운영형태는 기존 자전거도로 시설과 자전거이용자의 도로횡단특성을 수용하고, 교통 신호제어기의 기능변경 없이 신호시간의 조정만으로 적용이 가능한 이점이 있다.

• 대한한의학원전학회지
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• 제34권2호
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• pp.127-168
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• 2021

Objectives : First, the time of publication of the writing Jinjeong(陳情), was identified with consideration of current affairs at the time in Hamgyeongdo. Second, the relevance between agricultural policies and military/defense policies were identified. Third, based on these findings, the phrase "洋醜之漁獵頻泊汊 港, 峩人之耕牧恒據沿䐉" was throughly examined within its historical context. Methods : First, the time of publication of the writing Jinjeong(陳情), was identified with consideration of current affairs at the time in Hamgyeongdo. Second, the relevance between agricultural policies and military/defense policies were identified. Third, based on these findings, the phrase "洋醜之漁獵頻泊汊 港, 峩人之耕牧恒據沿䐉" was throughly examined within its historical context. Results & Conclusions : 1. The Jinjeong(陳情) of the Dongmuyugo(東武遺稿) is a writing on crossing borders into the Maritime Province of Siberia, which was written between the end of September and December of 1870. 2. The phrase "洋醜之漁獵頻泊汊港" is related to the incident when a handover line was at anchor in the Unggi harbor three times in 1869. 3. "我人之耕牧恒據沿海" refers to the rumor spread in 1870 about Russia being an ideal country that practiced ideal politics, to the extent of cattle and horse being gifted to immigrants into the country.

• Wind and Structures
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• 제11권4호
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• pp.303-321
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• 2008

When first commissioned, the 1.6 km span 275kV Severn Crossing Conductor experienced large amplitude vibrations in certain wind conditions, but without ice or rain, leading to flashover between the conductor phases. Wind tunnel tests undertaken at the time identified a major factor was the lift generated in the critical Reynolds number range in skew winds. Despite this insight, and although a practical solution was found by wrapping the cable to change the aerodynamic profile, there remained some uncertainty as to the detailed excitation mechanism. Recent work to address the problem of dry inclined cable galloping on cable-stayed bridges has led to a generalised quasi-steady galloping formulation, including effects of the 3D geometry and changes in the static force coefficients in the critical Reynolds number range. This generalised formulation has been applied to the case of the Severn Crossing Conductor, using data of the static drag and lift coefficients on a section of the stranded cable, from the original wind tunnel tests. Time history analysis has then been used to calculate the amplitudes of steady state vibrations for comparison with the full scale observations. Good agreement has been obtained between the analysis and the site observations, giving increased confidence in the applicability of the generalised galloping formulation and providing insight into the mechanism of galloping of yawed and stranded cables. Application to other cable geometries is also discussed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.216-217
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• 2010

This paper presents a new software-based on-line dead-time compensation technique for single-phase grid-connected photovoltaic (PV) inverter system. To improve the mitigation of dead-time effect around the zero-crossing point of phase current, a selective harmonic elimination of instantaneous feedback current is used as an additional part of conventional current control scheme. Simulation and experimental results are shown to verify the effectiveness of proposed compensation method in the grid-connected power distributed generation systems.