• 소음진동
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• 제8권5호
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• pp.929-935
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• 1998

Safety diagnosis of electric train driving system is performed using vibration signals of running electric train. Safety diagnosis is tried on the viewpoints of the appreciation of superannuation and the fault diagnosis of motor, reduction gear and bogie. The appreciation of superannuation is checked by the vibration levels of driving parts and the fault diagnosis is done by analyzing the frequencies of the vibration signals which are measured directly from a running electric train. The results shows that the vibration levels of each parts increase as the train gets older and each parts have their own frequency patterns of the vibration. Vibration propagation path is also investigated using calculated the coherence value between bogie and driving system. As the results, it is known that vibration signal can be utilized successfully for the safety diagnosis of the driving part of electric train.

• 한국도로학회논문집
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• 제20권1호
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• pp.137-146
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• 2018

PURPOSES : This study aims to analyze how the installation of advanced warning devices affects individual drivers' driving behaviors with operating record data collected from 100 vehicles. METHODS : With collected data, the changes in individual drivers' driving behaviors, such as Forward Collision Warning (FCW) and Lane Departure Warning (LDW), were investigated with respect to the cumulative distance traveled and driving time. For the analysis, operating record data collected from 100 vehicles for seven months were used. RESULTS : The results showed that individual drivers' driving behaviors could be categorized into six different types. In addition, most of the drivers showed unstable warning patterns in the initial stage after installation of an advanced warning device. Approximately 40% of vehicles equipped with advanced warning systems were found to have positive effects, indicating that the frequencies of both FCW and LDW had been continuously decreasing after installation of the system. CONCLUSIONS : The warning device might be helpful for making drivers' driving behaviors safer. Driving behaviors during the initial stage of the system installation, which might be regarded as an adaptation phase, were found to be very unstable compared with normal situations, indicating that adequate education and training should be provided to all the drivers to prevent operator disruption at the initial installation of the system.

• 한국자동차공학회논문집
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• 제21권6호
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• pp.123-134
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• 2013

Strengthening vehicle emission regulation is one of important policies to improve air quality in urban area. Due to the limitation of specified driving cycles for certification test to reflect real driving conditions, additional off-cycle emission regulations have been adopted in US and being developed in Europe. The driving cycles of US or Europe have been used in emission certification for Korean light-duty vehicles, but it has not been known how well the driving cycles reflect various real driving patterns in Korea. In that point of view, it is required to estimate vehicle emission based on real road driving conditions to raise the effectiveness of vehicle emission regulation in Korea. In this study, real driving emission measurements have been conducted for three Korean light-duty vehicles with PEMS. The driving routes consisted of urban, rural and motorway in Seoul and Incheon. The data have been analyzed with various averaging methods including moving averaging windows method and compared to emission limits set with emission certification modes applied to tested vehicles. The results have shown that the real driving pollutant emissions of a gasoline and a LPG vehicles have been ranged quite lower than those of emission limits on CVS-75 driving cycle. But real driving NOx of a light duty diesel vehicle has been considerably higher than emission limit of NEDC driving cycle. The higher than expected NOx emission of a diesel vehicle might be caused by different strategy to control EGR in real driving condition from NEDC driving.

• 정보보호학회논문지
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• 제23권5호
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• pp.919-929
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• 2013

최근에 많은 IT기술들이 자동차에 적용되고 있다. 하지만 일부 자동차 IT 기술들은 보안에 대한 적절한 고려 없이 자동차에 적용되어 보안 사고를 야기할 수도 있다. 특히 최근의 연구 결과들은 차량 소유자 인증을 해주는 특정 모델의 스마트키가 무선 신호를 재전송하거나 이를 위조하는 공격으로부터 안전하지 않고, 이를 통해 차량을 탈취할 수 있음을 실험을 통해 증명하였다. 따라서 본 논문에서는 스마트키의 무선 신호 조작 공격을 이용한 차량도난으로부터 안전한 차량 운전자 인증 방법을 제안한다. 오늘날 차량에 구축된 전자장치간의 네트워크에서는 운전자의 운전 패턴에 대한 정보를 얻을 수 있다. 본 논문에서는 이러한 차량 소유자의 운전 패턴 정보를 학습시켜 이를 표준 정규분포화한 후, 운전자에 대한 인증이 가능한 인증 모델을 설계하였다. 또한 제안하는 인증 모델을 검증하기 위해 k-묶음 교차 검증을 수행하였고, false positive rate가 0.35일 때 true positive rate 0.7 로 운전자 인식이 가능함을 확인하였다. 제안하는 인증모델은 차량 소유자에게 연락할 수 있는 모듈(eg. 3G/4G 통신 module)과 함께 사용된다면 기존의 소유기반(스마트 키)의 인증 방식 보다 더 안전하게 차량을 보호할 수 있다.

• 한국ITS학회 논문지
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• 제23권1호
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• pp.26-41
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• 2024

안전한 도로교통 환경 조성을 위하여 운전행동에 영향을 미치는 인적요인에 관한 연구가 필요하지만, 실제 주행행태에 영향을 미치는 개인별 인적요인 특성을 도출하기에는 많은 어려움이 있다. 이에, 개별 운전자의 자기 보고를 통하여 도출되는 위험운전성향을 분석하여 주행 행태 특성과 상관성이 있는지 확인하고, 교통상황에 따른 주행행태에 영향을 미치는 운전성향을 추정하는 방법을 제시하고자 하였다. 본 연구에서는 기존에 고안된 설문 기법을 활용하여 실험 참가자들의 위험운전성향을 여러 방법으로 도출하고, 가상환경 기반의 주행 시뮬레이터 실험을 통하여 도출된 주행행태 특성을 분석하여 위험운전성향과 주행행태 특성 간 유의미한 상관관계가 있는지 확인하였다. 실험 결과, 한국형 DBQ를 통하여 도출되는 난폭운전성향이 높은 사람들이 상대적으로 빠른 주행속도와 가속도 행태를 보이는 것을 확인할 수 있었다. 이를 통하여 상대적으로 위험운전행동을 보이는 운전자를 추정할 수 있는 평가 방법을 확인할 수 있었다.

• 한국산학기술학회논문지
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• 제9권1호
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• pp.35-40
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• 2008

본 논문에서 대전입자형 디스플레이 패널의 기본적인 구동방식 및 각각의 셀의 선택적 구동방식에 관하여 기술하였다. 패널을 제작하기 위해 $500{\mu}m{\times}500{\mu}m$의 셀면적을 가지고 있는 마스크패턴을 설계하였으며 기본적인 구동조건을 바탕으로 셀갭의 변화에 따른 구동전압의 변화를 관찰하였다. 수동메트릭스 방식으로 구동되는 패널의 각각의 셀을 선택적으로 구동하기 위해 선택된 셀과 선택되지 않은 셀의 전위차 상관관계를 확립하여 패널의 선택적인 구동을 수행하였으며 구동이 완료된 패널의 crosstalk현상을 관찰하였다. 또한 추가적인 전압을 인가하지 않아도 마지막 이미지가 오랜 시간 동안 유지되는 패널의 메모리 효과를 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.61-63
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• 2007

In high field (> 3 T) MR imaging, the magnetic field inhomogeneity in the target object increases due to the nonuniform electro-magnetic characteristics and relatively high Larmor frequency. Especially in the body imaging, the effect causes more serious problems resulting in locally high SAR(Specific Absorption Ratio). In this paper, we propose an optimized parallel-transmission RF coil element structure and show the utility of the coil by FDTD simulations to overcome the unwanted effects. Three types of TX coil elements are tested to maximize the efficiency and their driving patterns(amplitude and phase) optimized to have adequate field homogeneity, proper SAR level, and sufficient field strength. For the proposed coil element of 25 cm ${\times}$ 8 cm loop structure with 12 channels for a 3.0 T body coil, the 73% field non-uniformity without optimization was reduced to about 26% after optimization of driving patterns. The experimental as well as simulation results show the utility of the proposed parallel driving scheme is clinically useful for (ultra) high field MRI.

• 대한기계학회논문집B
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• 제33권5호
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• pp.358-364
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• 2009

This paper is to investigate the influence of driving patterns of slow and high speed vehicles on the performance of continuously regenerating diesel particulate filter(DPF) system matched with operating conditions in field application. The DPF performance test for field application was carried out for two identical DPFs installed to slow and high speed vehicles. A slow speed vehicle was selected among local buses which have driving patterns to repeat running and stop frequently, while a high speed vehicle was prepared to have long route of high speed over 60km/h like inter-city buses. In this test, the regeneration performance on the DPF of slow speed vehicle deteriorated because of high soot load index(SLI) in spite of same balance point temperature(BPT) distribution for high speed vehicle. The DPF of slow speed vehicle melted in the end because the rapid increase of back pressure caused high temperature over $1200^{\circ}C$ in the ceramic wall of DPF. The PM components like ash collected to the filter in the DPF were analyzed in order to investigate the cause of the defect and provide an operation performance of DPF system. In the result of the analysis, high levels of lubrication oil ash(Ca, Mg, P, Zn) were detected.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.329-332
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• 2003

The effects of an auxiliary address pulse driving scheme, in which an auxiliary short pulse was applied to the address electrode during a sustain-period, was examined under the various image patterns of the 42-inch WVGA ac-PDP. When the auxiliary address pulse driving scheme was applied, the luminance of the red, green and blue cells were measured respectively. The luminance, luminous efficiency and current were measured under the full-white pattern of the 42-inch ac-PDP. As a result, the luminance of blue cell was improved approximately by 17 %, whereas the luminous efficiency of the full-white pattern was improved approximately by 34 % without a misfiring discharge in comparison with conventional driving scheme.

• 한국자동차공학회논문집
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• 제12권4호
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• pp.191-197
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• 2004

This paper presents experimental results for human drivers' driving patterns and an Adaptive Cruise Control(ACC) strategy. Analyses have shown that female drivers' driving characteristic values such as time-gap and minimum clearance are larger than those of male drivers'. Human drivers tend to have more clearance margins at high speed than at low speed. At low speed, drivers are much more sensitive to the desired clearance than at high speed. A multi-vehicle detection method is presented to improve ride quality of an ACC. Simulation results have shown that the proposed ACC can provide superior performance compared to the ACC strategy which uses a single-vehicle detection method.