• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.39 no.5
• /
• pp.595-603
• /
• 2019

To alleviate the demand on private car that is constantly increasing, Busan Metropolitan City (BMC) has established Bus Rapid Transit (BRT) to revitalize public transportation. But there are no unified lane system between BRT and general bus stations, which makes off-lane turning general bus to contribute to congestion. And as the bottleneck phenomenon at entrance/exit accelerates the congestion, there has been huge dissatisfaction among commuting drivers. Therefore, this study identifies efficient methods to operate better through measuring civilian awareness. We evaluate both satisfaction and drawbacks on BRT service with Importance-Performance Analysis (IPA). We first distinguish the groups by the awareness on BRT and their main transit usage, and then clarify the difference between the groups. And as a result, the group who is positive to BRT and uses buses often demands improvement in bus indoor comfort and curbing jaywalking. On the other hand, group who is negative to BRT and uses private cars often demands improvement in lane changing and the moving speed of private cars. We next examines the groups with MDPREF, one method of Multidimensional Scaling (MDS). And we have clarified that the evaluating criteria and the individual attributes of the groups corresponds very well.

• Journal of Mechanical Science and Technology
• /
• v.19 no.9
• /
• pp.1742-1752
• /
• 2005

This paper presents a Multiple Target Tracking (MTT) Adaptive Cruise Control (ACC) system which consists of three parts; a multi-model-based multi-target state estimator, a primary vehicular target determination algorithm, and a single-target adaptive cruise control algorithm. Three motion models, which are validated using simulated and experimental data, are adopted to distinguish large lateral motions from longitudinally excited motions. The improvement in the state estimation performance when using three models is verified in target tracking simulations. However, the performance and safety benefits of a multi-model-based MTT-ACC system is investigated via simulations using real driving radar sensor data. The MTT-ACC system is tested under lane changing situations to examine how much the system performance is improved when multiple models are incorporated. Simulation results show system response that is more realistic and reflective of actual human driving behavior.

• Journal of Institute of Control, Robotics and Systems
• /
• v.21 no.3
• /
• pp.210-216
• /
• 2015

This paper proposes a method to determine vehicle driving state using the driving characteristics index. This index is a quantitative value to classify the driving state of a vehicle with its velocity and heading angle in that instant. It can classify driving state into straight driving, lane changing driving and curve driving in real time. In addition, the number of positional information is movably set up by designed region of interest. The proposed index is expressed on the stable driving states. Each driving state has characteristic tendency, and is compared with index distributional areas. The proposed method is verified by the actual driving experiment on the KATECH proving ground.

• Journal of Auto-vehicle Safety Association
• /
• v.8 no.4
• /
• pp.31-37
• /
• 2016

Since real road experiments have many restrictions, a multi-vehicle traffic simulator can be an effective tool to develop and evaluate fully automated driving systems. This paper presents multi-vehicle environment simulation tool to develop and evaluate motorway automated driving systems. The proposed simulation tool consists of following two main parts: surrounding vehicle model and environment sensor model. The surrounding vehicle model is designed to quickly generate rational complex traffic situations of motorway. The environment sensor model depicts uncertainty of environment sensor. As a result, various traffic situations with uncertainty of environment sensor can be proposed by the multi-vehicle environment simulation tool. An application to automated driving system has been conducted. A lane changing algorithm is evaluated by performance indexes from the multi-vehicle environment simulation tool.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.2
• /
• pp.132-140
• /
• 2002

A momentum backpropagation neural network is prepared to carry out real-time dynamics simulations of a passenger car. A full-car model of fifteen degrees of freedom was constructed for vehicle dynamics analysis. Human body dynamics analysis was performed for a male driver(50 percentile Korean adult) restrained by a three point seatbelt system. The trained data using the neural network were obtained using a dynamic solver, ADAMS . The neural network were formed based on the dynamics of the simulator. The optimized hidden layer was obtained by selecting the optimal number of hidden layers. The driving scenario including bump passing and lane changing has been used for the estimation of the proposed neural network. A comparison between the trained data and neural network outputs is found to be satisfactory to show the applicability of the suggested approach.

• Journal of Auto-vehicle Safety Association
• /
• v.14 no.1
• /
• pp.20-25
• /
• 2022

This paper presents a development of simulation environment for validation of autonomous driving (AD) algorithm based on Robot Operating System (ROS). ROS is one of the commonly-used frameworks utilized to control autonomous vehicles. For the evaluation of AD algorithm, a 3D autonomous driving simulator has been developed based on LGSVL. Two additional sensors are implemented in the simulation vehicle. First, Lidar sensor is mounted on the ego vehicle for real-time driving environment perception. Second, GPS sensor is equipped to estimate ego vehicle's position. With the vehicle sensor configuration in the simulation, the AD algorithm can predict the local environment and determine control commands with motion planning. The simulation environment has been evaluated with lane changing and keeping scenarios. The simulation results show that the proposed 3D simulator can successfully imitate the operation of a real-world vehicle.

• Journal of Korean Society of Transportation
• /
• v.20 no.6
• /
• pp.69-80
• /
• 2002

차로변경이 발생하는 두 가지 상황 즉, 강제 차로 변경과 선택적 차로 변경 중, 선택적 차로변경 상황에서 운전자가 수락 가능한 간격을 발견했을 때, 차로별 속도 차가 차로 변경 의사결정에 미치는 영향을 모사할 수 있는 모형식을 추정하였다. 즉, 선택적 차로 변경은 운전자의 차로 변경 여부에 대한 상황판단과 함께 목적 차로의 간격 수락여부에 대한 의사결정으로 이루어지는데, 본 논문에서는 목적 차로에 수락 가능한 간격이 존재할 경우 차로별 속도차가 운전자의 의사결정에 어떤 영향을 미치는지에 대해 분석하였다. 이를 위해, 운전자 의 의사결정에 영향을 미칠 수 있는 다른 요소 즉, 중차량, 기하구조, 및 합·분류의 영향을 최소화하는 지점을 선택하여 표본조사를 실시하였으며, 보다 설명력 있는 모형식을 얻기 위해 상관분석 등을 수행하여 불필요하다고 생각되는 변수는 제외시켰다. 또한, 운전자의 희망속도와 주행 속도 차에 의한 영향을 반영하기 위해 현 차로 속도를 부가적인 변수로 추가하였으며, 계수추정은 통계패키지인 SAS를 이용하였는데, 자료분석에 있어, 속도차 구간에 따라 다른 간격수락 특성을 보여 차로별 속도차를 0∼2.0m/s구간과 2∼11.52m/s구간으로 나누어 분석을 수행하였다. 분석결과 속도차 0∼2.0m/s구간에서는 속도차가 증가할수록 차로 변경률이 높아졌으나, 2∼11.52m/s구간에서는 오히려 차로 변경률이 낮아지는 것으로 나타났는데, 이는 속도 차의 증감에 대해 운전자로 하여금 차로 변경을 유도하는 요소와 함께 저항하게 하는 요소가 있다는 것을 알 수 있었다. 분석결과. 2.0m/s 이상의 속도차에서 차로변경에 대한 저항이 상대적으로 크게 작용한다는 것을 알 수 있었으며, 도로 설계시 이를 반영하여 도로기하구조 및 안전성 등을 향상시킬 수 있을 것으로 보인다.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.10 no.6
• /
• pp.1-14
• /
• 2011

The surrogate safety assessment model which was developed based on the conflict theory by FHWA in the US is software to analyze traffic conflicts using the individual vehicle trajectory data from a microscopic traffic simulation model. This study aims at assessing the safety of different signal control strategies, including pre-time and actuated signal control, using the SSAM. To this end, this study effort has developed a microscopic traffic simulation model using VISSIM through a field study, and then produced the surrogate measures, including TTC, PET, DR, MaxS and DeltaS, and the numbers of conflicts, including rear-end, right angle and lane-changing conflicts. The assessment results indicated that the actuated signal control may produce more conflicts in terms of rear-end conflicts. The use of SSAM in the safety assessments for diverse traffic alternatives in a safe and fast way may contribute to the improvement of safety in the roadway transportation.

• Journal of KIISE:Software and Applications
• /
• v.30 no.5_6
• /
• pp.444-453
• /
• 2003

Recently, a great interest of bio-technology(BT) is concentrated and the image analysis technique for electrophoresis gels is highly requested to analyze genetic information or to look for some new bio-activation materials. For this purpose, the location and quantity of each band in a lane should be measured. In most of existing techniques, the approach of peak searching in a profile of a lane is used. But this peak is improper as the representative of a band, because its location does not correspond to that of the brightest pixel or the center of gravity. Also, it is improper to measure band quantity in most of these approaches because various enhancement processes are commonly applied to original images to extract peaks easily. In this paper, we adopt an approach to measure accumulated brightness as a band quantity in each band region, which Is extracted by not using any process of changing relative brightness, and the gravity center of the region is calculated as a band location. Actually, we first extract lanes with an entropy-based threshold calculated on a gel-image histogram. And then, three other methods are proposed and applied to extract bands. In the MER method, peaks and valleys are searched on a vertical search line by which each lane is bisected. And the minimum enclosing rectangle of each band is set between successive two valleys. On the other hand, in the RG-1 method, each band is extracted by using region growing with a peak as a seed, separating overlapped neighbor bands. In the RG-2 method, peaks and valleys are searched on two vertical lines by which each lane is trisected, and the left and right peaks nay be paired up if they seem to belong to the same band, and then each band region is grown up with a peak or both peaks if exist. To compare above three methods, we have measured the location and amount of bands. As a result, the average errors in band location of MER, RG-1, and RG-2 were 6%, 3%, and 1%, respectively, when the lane length is normalized to a unit value. And the average errors in band amount were 8%, 5%, and 2%, respectively, when the sum of band amount is normalized to a unit value. In conclusion, RG-2 was shown to be more reliable in the accuracy of measuring the location and amount of bands.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.1D
• /
• pp.65-72
• /
• 2011

When an expressway intersects another expressway, a unique connector needs to be designed between the two consecutive exit ramps. In such a case, it is important to design a connector such that there is enough distance for drivers to find their way safely. A current design manual in Korea prescribes the minimum length of the connector as 240 m. In this research, we have suggested a method for calculating the minimum length of a connector in order to check the feasibility of the currently prescribed length. For this purpose, we have attempted to determine the total perception-reaction time and lane-changing time required by a driver. For determining the driver's perception-reaction time, we have used the driver's decision time in addition to the conventional 2.5 s of perception-reaction time for stopping sight distances. We have considered both the design speed and the average travel speed for the calculation of the length. To evaluate the accuracy of the new method, we have chosen four sites on expressways for which relatively high accident rates were recorded. As a result, we could verify that the current limit (240 m) was sufficient for drivers to be able to change lanes in the given specific geometry. However, the prescribed limit should be revised in case the drivers' decision time is considered to be their perception-reaction time. All new approaches for calculating the ideal length of a connector have been carried out by taking into account the design speed as well as the average travel speed. Owing to the characteristics of the specific geometry for two consecutive exit ramps and the large difference between the design speed and the average travel speed in the objective areas, it is more realistic to use the proposed method by keeping the decision time equal to a driver's perception-reaction time, in order to determine the ideal distance that should be maintained between two consecutive exit ramps.