• KIPS Transactions on Computer and Communication Systems
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• v.7 no.6
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• pp.137-144
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• 2018

Vehicular Ad-hoc Networks (VANETS) have enabled to provide a variety of applications such as accident notification, content usage, etc. These applications have spatio-temporal data which have an interesting region and a lifetime according to their properties. However, geocasting protocols to deliver data to an interesting region can provide data to all vehicles in the region through a single transmission only at the current time, but cannot provide data to vehicles passing through the region during the lifetime of the data. Thus, we propose a spatio-temporal geocasting protocol called STGP using a regional caching scheme to send data to vehicles in an interesting region during a data lifetime in VANETs. For efficient and reliable regional caching, the proposed protocol uses the beacon-based data sharing, the extra caching elimination, and the distance-based caching exchange. Simulation results verify that the proposed protocol achieves more reliable and efficient data delivery compared with the existing protocol.

• Journal of Korean Society of Transportation
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• v.27 no.5
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• pp.125-134
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• 2009

Recently, as IT technology and the ubiquitous environment have diffused, the application of these techniques are being attempted in the field of traffic operations and management. Therefore, it is necessary to develop data collection systems and signal control strategies that are suitable in the ubiquitous environment and that will improve efficiency and safety of signalized intersections. The authors conducted a study on the Wireless Sensor Network (WSN) signal control strategy using a wireless communication network between individual vehicles and a signal-control system and full actuated signal control technique to propose a new signal control strategy in the ubiquitous environment. The WSN was defined to evaluate the algorithm used with PARAMICS API simulation. The simulation produced results that the WSN signal control is more effective than other signal control methods. The WSN signal control could reduce vehicle delay time to a maximum of 64% in comparison with other signal control methods in low and near saturation flow conditions.

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.26-36
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• 2022

Recently, studies have been conducted to cluster vehicles and disseminate safety messages in a VANET environment for driver safety and smoothy traffic. This paper proposes cluster management scheme for safety message dissemination through V2V communication and V2I communication in a VANET environment with high vehicle density and mobility. The proposed scheme reduces packet loss by selecting CH considering reception quality, total data owned by vehicles, moving speed, and connected vehicles, and maintaining cluster head candidates, which are the main agents of message dissemination, considering frequent cluster departures and subscriptions. In addition, the proposed scheme reduces duplicate messages by utilizing clusters by collaborating with a Road side unit(RSU). To prove the excellence of the proposed scheme, various performance evaluations are performed in terms of message packet loss and the number of RSU processing requests. As a result of performance evaluation, the cluster management scheme proposed in this paper shows better performance than the existing scheme.

• Journal of Broadcast Engineering
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• v.25 no.3
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• pp.386-398
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• 2020

We developed an integrative annotation program that can perform data labeling process for deep learning models in object recognition. The program utilizes the basic GUI library of Python and configures crawler functions that allow data collection in real time. Retinanet was used to implement an automatic annotation function. In addition, different data labeling formats for Pascal-VOC, YOLO and Retinanet were generated. Through the experiment of the proposed method, a domestic vehicle image dataset was built, and it is applied to Retinanet and YOLO as the training and test set. The proposed system classified the vehicle model with the accuracy of about 94%.

• Journal of IKEEE
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• v.26 no.4
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• pp.622-627
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• 2022

This paper proposes an intrusion detection system for in-vehicle network to improve detection performance considering attack counts and attack types. In intrusion detection system, both FNR (False Negative Rate), where intrusion frame is misjudged as normal frame, and FPR (False Positive Rate), where normal frame is misjudged as intrusion frame, seriously affect vechicle safety. This paper proposes a novel intrusion detection algorithm to improve both FNR and FPR, where data frame previously detected as intrusion above certain attack counts is automatically detected as intrusion and the automatic intrusion detection method is adaptively applied according to attack types. From the simulation results, the propsoed method effectively improve both FNR and FPR in DoS(Denial of Service) attack and spoofing attack.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.812-815
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• 2011

통신기술이 발달하면서 차량 통신에 대한 연구가 활발히 진행되고 있다. 주 연구 분야로 라우팅 및 위치정보 기반의 주소 설정과 통신, 보안 문제 해결 등이 있다. 차량은 지극히 개인적인 공간이므로 운전자의 위치 및 식별정보에 대한 보호가 필요하다. 이러한 연구는 운전자 프라이버시 보호 측면에서 보안기능과는 별도로 연구가 진행되고 있다. 기존의 프라이버시 보호 기술들은 각 계층별 프라이버시 보호는 만족하고 있지만, 계층별 정보들의 연결을 통해 프라이버시를 공격하는 연관 공격(Relation Attack)에 대하여서는 취약함을 보이고 있다. 따라서 본 논문에서는 MAC Security 기술을 이용하여 운전자의 프라이버시를 보호하는 기법을 제안하려 한다. 제안하는 기법은 네트워크 접속 계층 주소를 제외한 나머지 정보를 암호화 하기 때문에 물리 주소로 인한 프라이버시가 침해가 발생 하더라도 다른 계층의 정보를 알 수 없으므로 네트워크 계층의 위치 정보 및 응용계층의 사용자의 식별 정보 등을 보호 함으로 상관 공격에 안전하다. 물리 주소 역시 해당 도메인에서 유일한 식별 정보 이므로 멀티 도메인 통신이 이루어 지는 인터넷 상에서는 운전자의 프라이버시를 보호 할 수 있다.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.2
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• pp.64-70
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• 2021

Nowadays, there are significant interests in real-time remote control using wireless networks. In implementing real-time remote control, one important factor is delay performance of real-time control message. Especially, the technique to reduce jitter of delay is necessary in transmitting periodically real-time control message. In this paper, we proposed synchronized transmission to reduce jitter of delay, when real-time control message was transmitted through wireless networks. The proposed transmission kept synchronization between source node and wireless transmitter and controlled transmission instance to transmit real-tie control message with fixed delay in wireless networks. According to results of experiment in military unmanned vehicle system, the proposed transmission reduced jitter of delay as 32% as that of a non-employing case.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1B
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• pp.1-8
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• 2012

In this paper, we propose an algorithm to improve collision avoidance in Vehicle-to-Vehicle (V2V) networks based on IEEE 802.11p. Since IEEE 802.11p adopts CSMA/CA as a multiple access scheme and an emergency warning message (EWM) is delivered to behind vehicles in a multi-hop manner, due to transmission collision, the more vehicles in the vehicle chain results in a longer delay. The longer delay increases the possibility of a rear-end collision. In order to ensure message reception with low latency, we consider implicit acknowledgement of a broadcasted EWM message and propose an algorithm to reduce redundant message transactions, called Two-Way Implicit Acknowledgement (TWIA). By simulations, we show that our proposed algorithm can reduce the latency until the last car receives the message by 9% and the success rate every car receives the message within 0.7sec by 12% at 100 fixed-number-of-car environment.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06b
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• pp.455-459
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• 2010

본 논문에서는 운전자의 운전 패턴에 따른 연료 소비량을 감소하는 ECO_Driving에서 효율적으로 방법을 제안하였다. 이 ECO-Driving 시스템은 차량의 정확한 상태 정보를 바탕으로 운전 상태를 운전자에게 제공하여 경제운전 행동으로 배기가스 감축, 에너지절약을 유도하였다. 차량의 상태정보를 추출하기 위해서 차량 네트워크인 CAN 버스를 사용하였으며, 이를 하드웨어로 구현하였다. 효율적인 ECO_Driving을 위한 차량 데이터들을 추출하여 분석하였으며, 이들 데이터를 바탕으로 운전자에게 에코여부를 제공하는 프로그램을 구현하였다. 제한적인 실험이었지만 연비를 감소하는 것을 확인할 수 있었다.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.245-247
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• 2011

VANET(Vehicular Ad Hoc Network)는 MANET(Mobile Ad Hoc Network)의 일부분으로 무선 애드 혹 네트워크를 구축하는 기술로 기본적인 인프라 없이 차량 간의 통신이 가능하다. VANET의 차량 간 통신으로 도로 상황이나 충돌 사고를 알려주는 응급 메시지를 송수신할 수 있으며 이로 인해 연쇄 충돌 사고를 피할 수 있다. VANET의 응급 메시지는 브로드캐스트 방법을 사용하여 일정 범위 내에 있는 차량들에게 메시지를 전송한다. 그러나 브로드캐스트 메시지를 보낼 경우 메시지 간의 충돌이 일어나 메시지 수신에 시간이 지연된다. 본 논문에서는 브로드캐스트 메시지를 보냈을 경우 메시지 간의 충돌로 인한 메시지 폭증을 막기 위해서 일정 랜덤 대기 시간을 기다린 후 메시지를 브로드캐스트하는 기법을 제안한다. 일정 랜덤 대기 시간을 기다린 후 메시지를 브로드캐스트하게 되면 순수 브로드캐스트 기법보다 충돌이 적어져 메시지 수신 지연 시간이 적어진다.