• 대한기계학회논문집A
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• 제26권5호
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• pp.969-975
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• 2002

Visual effects are important cues for providing occupants with virtual reality in a vehicle simulator which imitates real driving. The viewpoint of an occupant is sensitively dependent upon the occupant's posture, therefore, the total human body motion must be considered in a graphic simulator. A real-time simulation is required for the dynamic analysis of complex human body motion. This study attempts to apply a neural network to the motion analysis in various driving situations. A full car of medium-sized vehicles was selected and modeled, and then analyzed using ADAMS in such driving conditions as bump-pass and lane-change for acquiring the accelerations of chassis of the vehicle model. A hybrid III 50%ile adult male dummy model was selected and modeled in an ellipsoid model. Multibody system analysis software, MADYMO, was used in the motion analysis of an occupant model in the seated position under the acceleration field of the vehicle model. Acceleration data of the head were collected as inputs to the viewpoint movement. Based on these data, a back-propagation neural network was composed to perform the real-time analysis of occupant motions under specified driving conditions and validated output of the composed neural network with MADYMO result in arbitrary driving scenario.

• 한국정보통신학회논문지
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• 제15권12호
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• pp.2619-2625
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• 2011

최근 차량 항법 장치에서 널리 사용되고 있는 GPS 기술은 다음과 같은 두 가지 문제점을 가지고 있다. 첫째, 빌딩숲, 터널 등과 같은 도시 계곡(Urban Canyon) 지역에서는 GPS 신호 수신이 불가능하다. 둘째, GPS 신호를 이용한 측위는 항상 내재적인 위치 오차율 갖고 있다. 전자는 기존의 많은 연구를 통해 해결되었지만, 후자는 여전히 병행 도로와 같은 지역에서는 부정확한 위치 정보를 운전자에게 제공한다. 이 논문에서는 차량 네트워크와 기타 장비로부터 획득한 영상을 이용하여 차량의 주행 경로를 인식하는 시스템을 제안한다. 제안한 시스템은 실시간 영상 매칭 알고리즘을 이용한다. 또한 영상 매칭 정확도를 높이기 위한 기법 또한 제안한다. 이 논문에서 제안한 시스템은 실시간 주행 실험을 통해 원활하게 동작함을 보였다. 또한 매칭 정확도가 향상됨을 보여주었다.

• International Journal of Automotive Technology
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• 제7권5호
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• pp.603-608
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• 2006

As an important and relatively easy to implement technology for realizing Intelligent Transportation Systems(ITS), Adaptive Cruise Control(ACC) automatically adjusts vehicle speed and distance to a preceding vehicle, thus enhancing driver comfort and safety. One of the key issues associated with ACC development is usability and user acceptance. Control parameters in ACC should be optimized in such a way that the system does not conflict with driving behavior of the driver and further that the driver feels comfortable with ACC. A driving simulator is a comprehensive research tool that can be applied to various human factor studies and vehicle system development in a safe and controlled environment. This study investigated driving behavior with ACC for drivers with different driving styles using the driving simulator. The ACC simulation system was implemented on the simulator and its performance was evaluated first. The Driving Style Questionnaire(DSQ) was used to classify the driving styles of the drivers in the simulator experiment. The experiment results show that, when driving with ACC, preferred headway-time was 1.5 seconds regardless of the driving styles, implying consistency in driving speed and safe distance. However, the lane keeping ability reduced, showing the larger deviation in vehicle lateral position and larger head and eye movement. It is suggested that integration of ACC and lateral control can enhance driver safety and comfort even further.

• 한국멀티미디어학회논문지
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• 제14권12호
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• pp.1536-1543
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• 2011

Video stabilization is a very important step for vision based applications in the vehicular technology because the accuracy of these applications such as obstacle distance estimation, lane detection and tracking can be affected by bumpy roads and oscillation of vehicle. Conventional methods suffer from either the zooming effect which caused by a camera movement or some motion of surrounding vehicles. In order to overcome this problem, we propose a novel video stabilization method using FOE(Focus of Expansion). When a vehicle moves, optical flow diffuses from the FOE and the FOE is equal to an epipole. If a vehicle moves with vibration, the position of the epipole in the two consecutive frames is changed by oscillation of the vehicle. Therefore, we carry out video stabilization using motion vector estimated from the amount of change of the epipoles. Experiment results show that the proposed method is more efficient than conventional methods.

• 제어로봇시스템학회논문지
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• 제7권6호
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• pp.550-557
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• 2001

There are several applications and error analysis methods using GPS(Global Positioning System) In most analysis positioning and timing errors are represented as the multiplication of DOP(Dilution Of Precision) and measurement errors, which are affected by the receiver and measurement type. Therefore, lots of DOPs are defined and used to analyze and predict the performance of positioning and timing systems. In this paper, the relationships between these DOPs are investigated in detail, The relationships between GDOP(Geometric DOP), PDOP(Position DOP) and TDOP(Time DOP) in the absolute positioning are de-rived. Using these relationships, the affect of clock bias is analyzed. The relationships between RGDOP(Relative DOP) and PDOP are also derived in relative positioning where the single difference and double dif-ference techniques are used. From the results, it is expected that using the common clock will give better performance when the single difference technique is used while the effects of clock is eliminate when the double difference technique is used. Finally, the error analyses of dual frequency receivers show that the narrow lane measurements give more accurate results than wide line of or L1. L2 independent measurements.

• 자동차안전학회지
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• 제14권4호
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• pp.70-76
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• 2022

This paper investigates the effects of age, gender, and situational factors on take-over performance in automated driving. The existing automated driving systems still consider a driver as a fallback-ready user who is receptive to take-over requests. Thus, we need to understand the impact of situations and human factors on take-over performance. 34 drivers drove on a simulated track, consisting of one baseline and four event scenarios. The data, including the brake reaction time and the standard deviation of lane position, and physiological data, including the heart rate and skin conductance, were collected. The analysis was performed using repeated-measures ANOVA. The results showed that there were significant age, gender, and situational differences in the takeover performance and mental workload. Findings from this study indicated that older drivers may face risks due to their degraded driving performance, and female drivers may have a negative experience on automated driving.

• 한국자동차공학회논문집
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• 제21권4호
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• pp.62-69
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• 2013

Visual demands associated with in-vehicle display usage and text messaging distract a driver's visual attention from the roadway. To minimize eyes-off-the-road demands, voice interaction systems are widely introduced. Under cognitively distracted condition, however, awareness of the operating environment will be degraded although the driver remains oriented to the roadway. It is also know that the risk of inattentive driving varies with age, thus systematic analysis of driving risks is required for the older drivers. This paper aims to understand the age-related driving performance degradation and visual attention changes under auditory cognitive demand which consists of three graded levels of cognitive complexity. In this study, two groups, aged 25-35 and 60-69, engaged in a delayed auditory recall task, so called N-back task, while driving a simulated highway. Comparisons of younger and older drivers' driving performance including mean speed, speed variability and standard deviation of lane position, and gaze dispersion changes, which consist of x-axis and y-axis of visual attention, were conducted. As a result, it was observed that gaze dispersion decreased with each level of demand, demonstrating that these indices can correctly rank order cognitive workload. Moreover, gaze dispersion change patterns were quite consistent in younger and older age groups. Effects were also observed on driving performance measures, but they were subtle, nonlinear, and did not effectively differentiate the levels of cognitive workload.

• 한국항만경제학회지
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• 제23권2호
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• pp.1-24
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• 2007

빠른 경제성장과 교역량의 증가에 힘입어 중국은 이제 세계에서 가장 많은 컨테이너 물동량을 처리한 국가가 되었다. 그리고 컨테이너선의 대형화와 신속화 추세에 발맞추어 동북아 주요항만이 직면하는 환경도 상당히 빠르게 변하고 있다. 상해항은 육지로부터 약 30km 떨어진 대양산과 소양산을 개발하여 2005년 말에 제1기 터미널을 그리고 2006년에 제2기 터미널을 개장하였다. 그리고 2012년까지 전체 29선석을 조성하여 1,500만 TEU를 처리할 예정으로 있다. 컨테이너 처리물량에서 부산항을 추월한 상해항은 2,006년도 연간 물동량을 약 2,170만 TEU를 처리하여 세계 제3위의 지위를 확고히 했으며, 향후 세계 제1위의 컨테이너 처리항만으로 부상할 것으로 보인다. 세계 제5위의 컨테이너 처리항만이고, 동북아 중심항만이 되고자 하는 부산항에 양산항의 개장 및 향후 개발 계획에 따른 주변 상황에 능동적으로 대처하기 위한 다양한 대응전략을 제시해 본다.

• 한국콘텐츠학회논문지
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• 제19권1호
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• pp.125-131
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• 2019

소실점이란 실제 공간의 평행한 선들이 영상 내에 투영되면서 한곳에 모이는 점으로, 도로 공간에서의 소실점은 매우 중요한 공간정보이다. 도로 공간에서의 소실점을 이용해 추출된 차선의 위치를 개선하거나, 깊이지도 영상을 생성할 수 있다. 본 논문에서는 자동차의 시점을 기준으로 도로를 촬영한 영상을 Deep Neural Network(DNN)과 Histogram of Oriented Gradient(HoG) Feature를 이용한 소실점 검출 방법을 제안한다. 제안하는 알고리즘에서는 영상을 블록별로 나눠서 주요 에지 방향을 추출하는 HoG Feature 추출 단계와 DNN 학습 단계, 그리고 Test 단계로 나뉜다. 학습단계에서는 자동차 시점으로 기준으로 도로 영상 2300장으로 학습을 진행한다. 그리고 Test 단계에서는 Normalized Euclidean Distance(NormDist) 방법을 사용하여 제안하는 알고리즘의 효율성을 측정한다.

• 한국산학기술학회논문지
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• 제22권2호
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• pp.507-513
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• 2021

본 연구는 노면 흔적이 발생하지 않은 충돌 사고 사례를 중심으로 양 차량의 최종 정지 위치 및 자세, 차량 파손 부위, 노면 흔적, 차량의 제원, 충돌 각도. 충돌 속도, 제동 여부, 조향 여부 등의 자료를 토대로 교통 사고 분석을 위해 사용하는 차량 충돌 해석 시뮬레이션 프로그램인 PC-CRASH을 이용하여 시뮬레이션을 수행하였다. 차대 차 사고에서 충격 자세, 제동 여부, 최종 정지 위치, 충격 지점 및 충돌 속도는 사고 재구성을 위한 중요한 요소이다. 특히, 충돌 속도는 가장 중요한 쟁점이다. SM5와 렉서스의 충돌 속도는 각각 131km/h, 74km/h, SM5와 렉서스의 충돌각은 각각 0.91°, -161.07°으로 분석되었다. 사고 원인은 교차로를 통과하는 SM5가 최고 제한 속도를 61km/h 초과하여 렉서스의 좌회전 차로로 진입하였고, 렉서스는 충돌을 회피하기 위한 과정에서 충돌하였다. 시뮬레이션의 충돌 궤적 오차율은 약 1.4%이다. 사고 조사자의 주관적인 경험에서 벗어나 충돌 역학 및 차량 공학 측면과 시뮬레이션을 적극 활용하여 사실에 근접한 원인 규명을 제시하였다.