• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.4
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• pp.392-397
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• 2014

Recently, there are many researches on active safety system of intelligent vehicle. To reduce the probability of collision caused by driver's inattention and mistakes, the active safety system gives warning or controls the vehicle toward avoiding collision. For the purpose, it is necessary to recognize and analyze circumstances around. In this paper, we will treat the problem about collision risk assessment. In general, it is difficult to calculate the collision risk before it happens. To consider the uncertainty of the situation, Monte Carlo simulation can be employed. However it takes long computation time and is not suitable for practice. In this paper, we apply neural networks to solve this problem. It efficiently computes the unseen data by training the results of Monte Carlo simulation. Furthermore, we propose the features affects the performance of the assessment. The proposed algorithm is verified by applications in various crash scenarios.

• The KIPS Transactions:PartA
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• v.16A no.5
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• pp.381-388
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• 2009

The spread of wireless Internet technology development and applications with location information in the form of location-based services are becoming more diverse. In particular, where you recognize the location of objects such as people and things and to provide valuable services based on the ubiquitous and location-based services are emerging as an important service. The collision between the vehicle position measurement in this thesis and offers related service system. Used in the proposed system, the GPS PACKET with information about the location and time of collision for the vehicle crash, the vehicle consists of a NodeID. Cause a conflict between these data at the vehicle, the vehicle through the gateway from the server to decide whether to go on to determine that an emergency situation, Emergency Center, the location information and giving information about whether the conflict is measured. Also, for such an emergency, such as a family on the outside of the wireless terminal related to Wireless (PDA, Phone) is to let me know. The server to want to save the crash information to the database of configuration. Additionally, the proposed U-LBS system to verify the validity of the experiment was performed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1693-1700
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• 2012

Recently, the warning system to aid drivers for safe driving is being developed. The system estimates the distance between the driver's car and the car before it and informs him of safety distance. In this paper, we designed and implemented the collision warning system which detects the car in front on the actual road situation and measures the distance between the cars in order to detect the risk situation for collision and inform the driver of the risk of collision. First of all, using the forward-looking camera, it extracts the interest area corresponding to the road and the cars from the image photographed from the road. From the interest area, it extracts the object of the car in front through the analysis on the critical value of the shadow of the car in front and then alerts the driver about the risk of collision by calculating the distance from the car in front. Based on the results of detecting driving cars and measuring the distance between cars, the collision warning system was designed and realized. According to the result of applying it in the actual road situation and testing it, it showed very high accuracy; thus, it has been verified that it can cope with safe driving.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3B
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• pp.165-173
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• 2012

In this paper, we propose a random backoff scheme for Emergency Warning Messages (EWMs) in the vehicle-to-vehicle environment. The EWMs are disseminated from a vehicle that detects an emergency situation to other vehicles in a multi-hop fashion. Since the vehicle-to-vehicle communication based on IEEE 802.11 adapts CSMA/CA, the density of vehicles increase the probability of collisions between transmissions. Moreover, in the presence of background traffic, the EWM should have a higher priority than that of other messages in neighboring vehicles. To that end, we propose the Distant-Dependent Adaptive Backoff (DDAB) scheme, which set a different contention window for random backoff depending on the distance from the sender to the receiver. In the case when a vehicle is expected to located in the outskirts of the communication boundary, the proposed scheme makes the contention window size small in order to compete the background traffic transmission. Otherwise the contention window is set to a large number to reduce the collision possibility among the EWM transmissions. Via simulations, we show that the proposed scheme performs better than the previous schemes for EWM.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.163-166
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• 2001

본 논문에서는 ITS(Intelligent Transportation System) 기술중의 하나인 차량 충돌 방지 시스템의 신호처리부를 설계 구현하였다. 제안된 시스템은 FMCW (Frequency Modulated Continuous Wave)방식의 770Hz 밀리미터파 레이더를 기준으로 파라미터 값을 설계하여 거리와 속도를 실시간 검출하도록 구현되었다. 제안된 시스템은 TI사의 TMS320C31-40 DSP 와 AT89C52 Bbit 마이크로프로세서로 구현되어 10Hz 이상의 갱신율, 0.2m의 거리 분해능 및 2knvh의 속도 분해능을 제공하고 있다. 실험 환경으로 주파수 발생기(Function Generator)에서 비트주파수(Beat Frequency)를 생성하여 동작을 확인하였다.

• Journal of the Korea Society of Computer and Information
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• v.15 no.7
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• pp.41-47
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• 2010

The emergency between vehicles on the superhighway should be transmitted quickly to the following vehicles for safety of people. The message between them has been transmitted by broadcast method in an wireless environment of 802.11, so far. That causes the broadcast storm and a waste of the bandwidth of Wireless network owing to unnecessary process of sending messages to even vehicles that do not have to receive the information. The message collision is a main cause of the increase of message delay. In order to overcome the existing problem, this paper proposed a message broadcast scheme based on cell (MBC), which is the way to divide cars into different groups by cell unit and transmit messages to the members of the groups through the cell primary (cp) vehicles. This paper shows the proposed broadcast's performance in the same environment is much superior to other conventional broadcast schems for inter-vehicle communication, since the receiving ratio among the following vehicles is improved.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.342-345
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• 2003

자동운전과 안전운전 구현을 위한 첨단 차량 및 도로 시스템(AVHS : Advanced Vehicle & Highway Systems)의 한 분야인 충돌 방지 시스템을 완성하기 위해서는 차량간의 상대 거리, 차량의 속도, 차선의 굴곡 정도, 경사도등을 사용해서 종합적으로 상황 판단을 내려야 한다. 본 논문에서는 이들 요소들중에서 차선의 굴곡도 판단을 근사 추론을 이용하여 실험하였다. 근사추론을 이용한 것은 차선의 굴곡도를 계산형으로 파악할 때의 단점인 계산 시간 오버헤드(overhead), 또 그에 따른 실시간 처리의 어려움, 고가의 장비필요성 등을 극복하기 위해서이며, 실험은 Fuzzy Logical Inference 기법을 사용하였다. 본 연구에서는 실제 도로상에서의 계산된 굴곡도와 실험된 시스템 결과와의 유사성과 그 시스템의 사용 가용성(feasibility)을 검정하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4D
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• pp.539-546
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• 2011

Traffic accident collision interpretation is composed of various shapes, and speed variations working to the vehicle during collision are utilized as a very important factor in evaluating collision degrees between vehicles and safety of passengers who got in the vehicle. So, methods of interpreting results on speed variations utilizing simulation programs on the collision interpretation become necessary. By the way, reliability evaluation on each program is being required because various collision interpretations simulations are spread widely. This study utilized collision interpretation programs such as EDSMAC and PC-CRASH adopting completely different physical approaches, and then carried out collision experiments of one-dimensional front and two-dimensional right angle while changing values of a lot of collision factors such as vehicle's weight, center of gravity, rolling resistance, stiffness coefficient, and braking forces among early input conditions. Also, the study recognized effects of collision factors to speed variations as output results during crashing. As a result of this research, two simulation programs showed same speed variations together on the vehicle's weight, center of gravity, and braking forces. Stiffness coefficient of the vehicle reacted to EDSMAC only, and rolling resistance coefficient did not affect any particular influences on speed variations. However, there appeared a bit comparative differences from the speed variation's values, and this is interpreted as responding outcomes by applying fixed properties values to each simulation program plainly. Therefore, reliability on analysis of traffic accident collisions shall be improved by doing speed analysis after taking the fixed value of simulation programs into consideration.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.178-190
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• 1998

We have developed a planar impact model with a capability of reverse calculation to reconstruct various types of automobile collisions. This topic is the main part of what is referred to as accident reconstruction. The model uses the principle of impulse and momentum, and introduces a restitution coefficient and an impulse ratio at the impact center. Based on the car-to-car collision test results, we present how to estimate the restitution coefficient and the impulse ratio from some impact conditions. To validate the model and improve its reliability in accident analysis, the collision analysis has been performer with the estimated parameters. The analysis and experimental results agree well in the kinetic energy loss and the post-impact velocity.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.4
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• pp.53-64
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• 2009

Inter-vehicular communication that propagates information without infrastructures has drawn a lot of interest. However, it is difficult to apply conventional ad-hoc routing protocols directly in inter-vehicular communication due to frequent changes in the network topology caused by high mobility of the vehicles. MMFP(Multi-hop MAC Forwarding) is a unicast forwarding protocol that transport packets based on the reachability information instead of path selection or position information. However, delivering public safety messages informing road conditions such as collision, obstacles and fog through inter-vehicular communication requires broadcast rather than unicast since these messages contain information valuable to most drivers within a close proximity. Flooding is one of the simplest methods for multi-hop broadcast, but it suffers from reduced packet delivery-ratio and high transmission delay due to an excessive number of duplicated packets. This paper presents two multi-hop broadcast protocols for inter-vehicular communication that extend the MMFP. UMHB(Unreliable Multi-Hop Broadcast) mitigates the duplicated packets of MMFP by limiting the number of nodes to rebroadcast packets. UMHB, however, still suffers from low delivery ratio. RMHB(Reliable Multi-Hop Broadcast) uses acknowledgement and retransmission in order to improve the reliability of UMHB at the cost of increase in transmission delay, which we show through simulation is within an acceptable range for collision avoidance application.