• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.125-132
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• 2017

Vehicular safety service reduces traffic accidents and traffic congestion by informing drivers in advance of threats that may occur while driving using vehicle-to-vehicle (V2V) communications in a wireless environment. For vehicle safety services, every vehicle must broadcasts a Basic Safety Message(BSM) periodically. In congested traffic areas, however, network congestion can easily happen, reduce the message delivery ratio, increase end-to-end delay and destabilize vehicular safety service system. In this paper, to solve the network congestion problem in vehicle safety communications, we approximate the relationship between channel busy ratio and the number of vehicles and use it to estimate the total network congestion. We propose a new context-aware transmit power control algorithm which controls the transmission power based on total network congestion. The performance of the proposed algorithm is evaluated using Qualnet, a network simulator. As a result, the estimation of total network congestion is accurately approximated except in specific scenarios, and the packet error rate in vehicle safety communication is reduced through transmit power control.

• Journal of Multimedia Information System
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• v.5 no.2
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• pp.105-110
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• 2018

Autonomous cars require the integration of multiple communication systems for driving safety. Many carmakers unveil mirrorless concept cars aiming to replace rear and sideview mirrors in vehicles with camera monitoring systems, which eliminate blind spots and reduce risk. This paper presents optical vehicle-to-vehicle (V2V) communications for autonomous mirrorless cars. The flicker-free light emitting diode (LED) light sources, providing illumination and data transmission simultaneously, and a high speed camera are used as transmitters and a receiver in the OCC link, respectively. The rear side vehicle transmits both future action data and vehicle type data using a headlamp or daytime running light, and the front vehicle can receive OCC data from the camera that replaces side mirrors so as not to prevent accidents while driving. Experimental results showed that action and vehicle type information were sent by LED light sources successfully to the front vehicle's camera via the OCC link and proved that OCC-based V2V communications for mirrorless cars can be a viable solution to improve driving safety.

• ETRI Journal
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• v.45 no.6
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• pp.1065-1078
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• 2023

In vehicular networks, diverse safety information can be shared among vehicles through internet connections. In vehicle-to-internet communications, vehicles on the road are wirelessly connected to different cloud networks, thereby accelerating safety information exchange. Onboard sensors acquire traffic-related information, and reliable intermediate nodes and network services, such as navigational facilities, allow to transmit safety information to distant target vehicles and stations. Using vehicle-to-network communications, we minimize delays and achieve high accuracy through consistent connectivity links. Our proposed approach uses intermediate nodes with two-hop separation to forward information. Target vehicle detection and routing of safety information are performed using machine learning algorithms. Compared with existing vehicle-to-internet solutions, our approach provides substantial improvements by reducing latency, packet drop, and overhead.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.128-141
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• 2018

In this paper, a methodology to analyze the potential safe benefit of six cooperative driver assistance systems via V2V (vehicle-to-vehicle) communications is proposed. Although it is quite necessary to assess social impact with respect to new safety technologies for cooperative vehicles with V2V communications, there are few studies in Korea to predict the quantitative safety benefit analysis. In this study, traffic accident scenarios are classified based on traffic fatality between passenger cars. The sequential collision type is classified for a multiple pile-up with respect to collision direction such as forward, side, head-on collisions. Then movement of surrounding vehicle is considered for the scenario classification. Next, the cooperative driver assistance systems such as forward collision warning, blind spot detection, and intersection movement assistance are related with the corresponding accident scenarios. Finally, it is summarized how much traffic fatality may be reduced potentially due to the V2V communication based safety services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.3
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• pp.227-232
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• 2013

Due to the development of ITS technology, various services related to transportation under vehicular environments have been provided. Especially, as wireless communication technology, WAVE has been established as a standard for vehicle-to-vehicle communications. WAVE has fast connection and excellent mobility characteristics. A VSC-A project is conducting by global automotive OEMs in USDOT. This project introduces the advanced safety services with vehicle-to-vehicle communications. In this paper, we presented the scenario of a do not pass warning service, which prevents an accident during overtaking activity by using vehicle-to-vehicle communications. In addition, we analyzed network performance under WAVE. In conclusion, we introduced the simulation results. Finally, we summarized the communication range and delay values for consideration factors for a overtaking model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.2
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• pp.165-171
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• 2013

WAVE(Wireless Access in Vehicular Environments) is a representative V2V communication protocol and its standards of MAC and PHY parts except for security were published. In order to control traffic flow and ensure driver's safety using V2V communication, various projects are conducting. In particular, safety application has been researched. Therefore, in this paper, we designed the safety application algorithm, which informs a driver of the dangerous status when driver tries to turn left in an intersection and we also implemented the algorithm. Proposed algorithm configures a model for a host vehicle and a vehicle coming in opposite lane and in case that there is collision hazard it provides warning message to driver by using HMI. In order to evaluate the proposed algorithm's performance, we configured the test bed using test vehicles and we tested the algorithm on proving ground with the composed test scenarios. As test results, our system showed excellent performance. If the infrastructures for V2I communications are constructed, we will optimize our system more precisely and stably.

• 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.10 no.9
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• pp.319-324
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• 2012

Vehicle safety communications is one among the important technologies in order to protect a car accident. For this, many protocols forwarding a safe message have studied to protect a chain-reaction collision when a car accident occurs. most of these protocols assume that the time of generating a safe message is the same as an accident's. If a node predicts some traffic hazard and forwards a safe message, a driver can response some action quickly. So, In this paper, we proposes a traffic hazard prediction algorithm using the communication technique. As a result, we show that the frame reception success rate of using our algorithm to the previous protocol improved about 4~5%.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.13-16
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• 2015

In any mobile ad hoc environment, collision amongst mobile objects is always likely to occur unless there is a certain level of intelligence to detect and avoid the collision. This phenomenon of detection and avoidance is the key attribute for safety applications in vehicle to pedestrian (V2P) communications systems. In this paper, we propose a V2P communications concept for collision detection and avoidance.

• Information and Communications Magazine
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• v.19 no.9
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• pp.68-76
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• 2002