• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.3
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• pp.95-109
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• 2017

The golden time of emergency vehicle is directly connected to the public safety. Therefore, national attention has increased to cut down the emergency vehicle's travel time. In order to shorten the intial dispatch time of it, emergency preemption system was installed at five intersections, and after test operation, whether it could be introduced in the country was estimated. We analyzed the effect of the traffic volume, emergency vehicle's travel time, and queue length under preemption and non-preemption. In the verification of the emergency preemption system, it was confirmed that the emergency vehicle's travel time was reduced from 350% to 24% compared to non-preemption system(TOD). In the saturated condition, queue length were remained 15 minutes and near saturated condition was about 30 or 45 minutes. At the non-saturated condition, the queue length's difference between emergency preemption system and general signal was small.

• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.179-187
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• 2009

Currently, the signalized intersections in Korea are operated without providing an emergency vehicle preemption control strategy. Thus, it might threaten the safety of the pedestrians and drivers on highways when an emergency vehicle faces congested traffic conditions. The existing preemption control is activated when an emergency vehicle is detected along a path. This enables emergency vehicles to progress uninterrupted, but it also increases the delay of other vehicles. In this paper, a revised preemption control strategy considering queue length restrictions is proposed to make both a progressive movement of an emergency vehicle and reduce delay of other vehicles simultaneously. By applying the preemption control strategy through a simulation study, it was shown that delay of an emergency vehicle decreased to 44.3%-96.1% and speed increased to 8.8%-42.0% in all 9 cases as compared with a conventional signal control. The existing preemption control is superior for oversaturated conditions (v/c >1.0) or a link length less than 200m. However, the preemption control considering queue length constraints shows better performance than the existing preemption control when the v/c is less than 0.8 and a link length is longer than 500m.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.280-283
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• 2013

최근 원자력 발전소, 의료 시스템, 항공 시스템 등과 같이 사람의 생명과 밀접하게 관련되어 있는 소프트웨어로 제어하는 시스템들이 점차 늘어나고 있다. 차량에서 또한 차량 제어 소프트웨어의 오작동으로 인한 잦은 사고로 인하여 운전자와 탑승자의 생명을 위협 받고 있다. 이러한 문제로 인하여 차량시스템 제어 소프트웨어도 안전성 확보를 위한 기술로 차량에 통신 기술을 접목한 차량 통신 기술에 대한 관심이 높아지고 있다. 차량 운전자 뿐 아니라 탑승자의 안전과 밀접하기 때문에 많은 연구가 진행되고 있다. 이러한 많은 연구 중 긴급메시지전송 시스템은 차량 간 통신(V2V)을 통한 운전자의 안전성 확보에 대한 연구다. 본 논문에서는 차량 긴급메시지 전송에 필요한 모듈을 구조적으로 나누고 이를 통하여 긴급메시지 전송시스템 구조의 안전성을 평가한다. 긴급메시지 전송시스템의 안정성을 검증하기 위하여 오토마타 모델링을 통한 시스템 구조를 설계하고 검증을 위해 CTL 논리식 정의, SMV(Symbolic Model Verifier)검증도구를 통한 시스템 안전성 모델 검사를 하였다.

• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1297-1307
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• 2013

Several multi-hop applications developed for vehicular ad hoc networks use broadcast as a means to either discover nearby neighbors or disseminate useful traffic information to othet vehicles located within a certain geographical area. However, the conventional broadcast mechanism may lead to the so-called broadcast storm problem, a scenario in which there is a high level of contention and collision at the link layer due to an excessive number of broadcast packets. To solve broadcast storm problem, we propose an RPB-MACn-based LV-CAST that is a vehicular broadcast algorithm for disseminating safety-related emergency message. The proposed LV-CAST identifies the last node within transmission range by computing the distance extending on 1 hop from the sending node of an emergency message to the next node of receiving node of the emergency message, and the last node only re-broadcasts the emergency message. The performance of LV-CAST is evaluated through simulation and compared with other message dissemination algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10C
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• pp.749-757
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• 2008

In this paper, we propose an authentication scheme for EVPT (Emergency Vehicle Priority Transit) service in Vehiclar Ad-hoc Networks (VANET) enable a variety of vehicle comfort services, traffic management applications, and infotainment services. These are the basis for a new generation of preventive and active safety functions. By intelligently controlling signalling at intersections, providing additional information to the driver and warning the driver in critical situations. we therefore focus on vehicle-to-infrastructure communication for the authentication between emergency vehicles and traffic lights system. This authentication process should identify the vehicle, and provide privacy protection.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.5
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• pp.27-37
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• 2012

Even thought the firefighters have to hurry to the scene to extinguish the blaze, the fire engines could not rushed out due to the worst of traffic condition. Traffic signal control is one of the most important methods to minimize the fire engines's travel time. The focus of this paper is to develop a traffic control strategy, which is emergency vehicle preemption algorithm considering pedestrian in order to reduce travel time of emergency vehicle. This algorithm also includes recovering strategy after preemption signal to minimize the other vehicle's delay. In order to estimate the effectiveness of traffic control, traffic simulation was performed using VISSIM micro simulation tool for two different kinds of networks, which were non-coordinated corridor and coordinated corridor. The differences of travel time and average delay between emergency vehicle and ordinary vehicle were respectively estimated under pre-existed pretimed signal and preemption traffic control at two respective networks. The results of the simulation for the emergency vehicle, travel time was reduced to 36.8~43.3% under "Add or Subtract" method whereas it was reduced to 30.7~46.0% under "Dwell" method. In addition, in non-coordinated corridor case of ordinary vehicle, average control delay of "Dwell" method was increased 33.5% whereas it grew 0.5% under coordinated corridor. And "Add or Subtract" method was confirmed that average control delay of ordinary vehicle was increased 0.7% under non-coordinated corridor whereas it swelled 4.5% under coordinated corridor.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.1547-1550
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• 2013

현재 우리나라에서 사용되는 대부분의 교통신호 체계는 교통량의 변화와 상관없이 규칙적인 신호주기를 반복하는 방식으로 교통 패턴이 안정되어 변동량이 적은 경우에는 적합하나, 현장교통상황에 능동적으로 조정되지 못하고, 소방차나 구급차와 같이 긴급을 요하는 차량에 대한 대처가 힘들다는 단점이 존재한다. 따라서 유기적인 현장교통상황에 능동적으로 대처하고, 긴급차량에 대한 합리적인 대처 방법이 필요하다. 따라서, 본 논문에서는 이와 같은 문제점을 해결하고자 기 설치된 신호 후방 CCTV를 이용하여 지능적으로 신호체계를 제어하고, 긴급차량에 대해 신호우선권을 부여함으로써, 위급상황에 유기적으로 대처할 수 있는 지능형 교통신호 제어 시스템을 설계하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.205-210
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• 2006

차량간 무선통신을 이용한 긴급메시지 전파는 도로 주행 중에 발생할 수 있는 도로의 결빙, 낙석, 공사, 안개, 급커브 등의 위험 상황을 사전에 신속히 위험 지역의 차량들에게 알려 위험 상황 대처 능력을 크게 개선 할 수 있다. 그러나 차량간 통신은 일반적인 무선통신과 달리 노드의 고속 이동성, 노드 밀도, 네트워크 토폴로지의 빈번한 변화와 같은 차량 환경 고유의 특징을 가진다. 본 논문에서는 차량간 긴급메시지를 신속하게 전달하기 위한 시간예약 기반 릴레이 노드 선정 알고리즘을 제안하였다. 실험결과, 제안한 알고리즘이 거리 기반 릴레이 노드 선정 알고리즘에 비해 네트워크 부하와 전달 지연시간에서 25% 성능 향상을 보였으며, 낮은 노드 밀도에서는 더욱 우수한 성능을 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1113-1121
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• 2010

The Vehicle Safety Communications (VSC) is one of VANET applications for preventing vehicle accidents, and it utilizes vehicle-to-vehicle communication to exchange emergency messages. To propagate such messages in VSC, several schemes based on selective flooding have been proposed. Their common idea is that an emergency message is relayed by one of vehicles receiving the message. However, the schemes do not consider the transmission errors and duplications of an emergency event. In the schemes, if there are transmission errors and a vehicle detects a hazard, there may be vehicles which fail to receive an emergency message. If k vehicles detect a hazard, k emergency messages are created and propagated. The duplications of an event increase reliability of the message delivery but decrease efficiency. In this paper, we propose an emergency message delivery scheme which is efficient and robust to transmission errors. Our proposed scheme utilizes clustering for massage aggregation and retransmissions in a cluster. It also uses an acknowledgment mechanism for reliable inter-cluster communication. Our simulation results show that the proposed scheme outperforms Least Common Neighbor Flooding which is one of the selective flooding schemes.

• Journal of Digital Convergence
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• v.18 no.4
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• pp.229-236
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• 2020

As the number of elderly drivers increases, traffic accidents from the elderly also increase. In particular, the emergency situation of the elderly driver is not transmitted to the following vehicle during cloudy days and night highway accidents, so it is extended to the second and third accidents, leaving serious aftereffects. Therefore, there is an urgent need to establish an economic and effective inter-vehicle emergency communication system between the accident vehicle of the elderly and the following vehicles. In this paper, we have proposed a policy and method that can take advantage of the special emergency light pattern of an elderly driver in an emergency and transmit it to the following vehicles, thereby providing secondary accident prevention and emergency relief. Furthermore, by introducing an infrared emergency communication system between vehicles using red brake lights and implementing it as a prototype of RC-Car, we have checked the feasibility of the system.