• Journal of IKEEE
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• v.18 no.4
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• pp.495-501
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• 2014

In this paper, we designed a diversity modem hardware architecture for IEEE802.11p WAVE and tested the modem on the road with car attached shark antenna. One of the dual channel modem and the diversity single modem with maximum ratio combining algorithm can be selected on the designed architecture. The designed modem have been implemented on the Xillinx Kintex7 FPGA. We tested the modem performance on the smart highway experience road. As experimental results, we can verify the performance of the diversity modem on real road and the enlarged communication range by more than 30%.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.138-144
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• 2012

Recent environmental issues such as exhaust gas and greenhouse effect make the agricultural machinery market takes into account the hybrid and electric propulsion technology used in automotive engineering. Generally the agricultural machinery, particularly an agricultural tractor, needs large load capacity and long continuous operating time comparing with conventional vehicles. In case of a pure electric tractor, it is necessary for considering large capacity batteries and long charging time. Therefore we take an AER extended PHEV (All Electric Range extended Plug-in Hybrid Electric Vehicle) power transmission system in developing an electric tractor in this study. First we propose a PHEV powertrain structure in order to substitute the conventional diesel engine equipped tractor. And we performed the road tests using a conventional mechanical tractor with various load conditions, which were classified and statistically treated real agricultural works. The test results were analysed with respect to the power characteristics of the power source. Finally using the test result, we designed two-stepped reduction gear ratios in the proposed an electric tractor powertrain for carrying out typical agricultural works.

• Journal of the Korean Society for Railway
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• v.10 no.4
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• pp.414-419
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• 2007

The contact characteristics of the current collection system are investigated by analyzing data collected during a test run of the Korean high speed rail vehicle. For the analysis, the signals from accelerometers and load cells attached to the various parts of the pantograph are analyzed in both the time and frequency domains. In the frequency domain, the pantograph response consists of low frequency components related to the rigid-body motion of the panhead assembly and high frequency components due to the structural vibration modes of the pantograph. The analysis shows that the inclusion of the high frequency structural vibration modes of the pantograph in the contact force calculation has a negligible effect on the predicted mean value of the contact force but significantly affects the magnitude of its fluctuations. This finding implies that numerical simulations using lumped element models of the pantograph may accurately predict the mean contact force but is limited in its capacity for predicting the fluctuation about the mean. Since the ratio of the fluctuation to the mean in the contact force increases with increased train speed, the limitation of the predictions based on numerical simulation results becomes more pronounced at higher train speed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.4
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• pp.529-534
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• 1986

본 연구에서는 실차를 대상으로 유한요소 해석을 통하여 차체 및 차실의 구조 진동 및 음향모우드를 구한후 관련 실험에 의한 검증 및 보완을 통하여 설계단계에서 의 진동 및 소음수준을 저감시키는데 유용한 정보를 제공코저 하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.184-187
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• 1996

본 연구에서는 산업 현장에서 중장비 엔진마운트를 설계함에 있어서 벤치상태에서의 번거로움과 비현실성을 해결하고 실차상태의 하중 조건에 맞는 적절한 엔진마운트를 설계하기 위해 TDA(Time Domain Analysis) 기법을 도입하여 굴삭기 모델에 응용하여 이론치와 실험치를 비교 검토하고 승차감향상을 도모하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.346-347
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• 2010

• Journal of Advanced Navigation Technology
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• v.11 no.4
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• pp.359-370
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• 2007

Lane tracking and obstacle avoidance are considered two of the key technologies on an unmanned ground vehicle system. In this paper, we propose a method of lane tracking and obstacle avoidance, which can be expressed as vehicle control, modeling, and sensor experiments. First, obstacle avoidance consists of two parts: a longitudinal control system for acceleration and deceleration and a lateral control system for steering control. Each system is used for unmanned ground vehicle control, which notes the vehicle's location, recognizes obstacles surrounding it, and makes a decision how fast to proceed according to circumstances. During the operation, the control strategy of the vehicle can detect obstacle and perform obstacle avoidance on the road, which involves vehicle velocity. Second, we explain a method of lane tracking by means of a vision system, which consists of two parts: First, vehicle control is included in the road model through lateral and longitudinal control. Second, the image processing method deals with the lane tracking method, the image processing algorithm, and the filtering method. Finally, in this paper, we propose a method for vehicle control, modeling, lane tracking, and obstacle avoidance, which are confirmed through vehicles tests.

• Journal of Korean Society of Transportation
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• v.30 no.5
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• pp.83-90
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• 2012

Driver ordinarily takes sudden braking when urgent situation is developed or when the vehicle is involved in an unexpected accident. Therefore, the most common trace at a traffic accident scene is skid mark. Currently, in investigating traffic accident, overspeed is determined by the length of skid mark. However, in order to identify accurate cause of accident, estimation of pre-braking speed which takes into account speed reduction during transient time should be considered as a requirement. In a recent study, several ways to estimate pre-braking speed were suggested, but none considered to differentiate the decelerating transient brake section and skidding section. This study analyzed trends of decelerating transient brake section and skidding section by real braking test.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.149-160
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• 2007

Automobile black boxes store and provide accident and driving information. The accident and driving information can be utilized to build scientific traffic-event database and can be applied in various industries. The objective of this study is to develop a recognition system of dangerous driving through analyzing the driving characteristic patterns. In this paper, possible dangerous driving models are classified into four models on the basis of vehicle behaviors(acceleration, deceleration, rotation) and accident types from existing statistical data. Dangerous driving data have been acquired through vehicle tests using automobile black boxes. Characteristics of driving patterns have been analyzed in order to classify dangerous driving models. For the recognition of dangerous driving, this study selected critical value of each dangerous driving model and developed the recognition algorithm of dangerous driving. The study has been verified by the application of recognition algorithm of dangerous driving and vehicle tests using automobile black boxes. The presented recognition methods of dangerous driving can be used for on-line/off-line management of drivers and vehicles.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1995.06b
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• pp.7-13
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• 1995

현재 교통인구 비중에 큰 비중을 차지하고 있는 철도 차량은 기술의 발전으로 인한 고속화에 성공하여 300km/h대의 속도를 달성하기에 이르렀다. 열차가 고속화됨으로 인하여 열차 주행시 운동에너지가 더욱 커졌고 이를 소산하기 위한 제동 역시 더욱 중요하게 되었다. 열차의 제동시 중요한 점은 wheel의 skidding을 방지함으로 wheel의 편마멸을 줄이는 것이며 이를 위해선 제동장치의 설계시 wheel과 rail간의 점착현상의 이해가 필수적이다. 제동력이 점착력보다 클 경우는 skidding이 발생하며 제동력이 점착력보다 작은 경우는 충분한 제덩을 하지 못한다는 것을 의미한다. 그러므로 열차의 제동장치를 설계함에 있어서 점착계수는 필수적인 요소가 되었으며 미국, 일본, 독일 등의 선진 각국에서는 점착계수를 측정하여 그 특성을 파악하려는 실험이 실험실 및 실차 차원에서 많이 행하여졌다. 각각 다른 접척조건, 속도 등에 따른 실험이 진행되어 왔으나 각 연구의 결과는 조금씩 다른 결향을 나타내었고, 점착현상에 관한 물리적인 설명은 못하고 있는 실정이다. 본 연구에서는 wheel과 rail의 접촉인 경우에 있어 점착현상의 변화를 속도, 하중, 접촉조건에 따른다고 보고 점착현상의 특성을 각각 sliding, pure rolling실험을 통해 파악하고 기타 참고문헌에서 발표된 점착계수와 비교하여 물리적으로 이해하고자 하였다.