• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2014년도 추계학술발표대회
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• pp.171-172
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• 2014

This paper proposes a SDN based Proxy Mobile IPv6 (PMIPv6) architecture for heterogeneous vehicular networks (SDN-VANET), to provide the continuity of service during the horizontal handovers and to reduce the delay during vertical and horizontal handovers. SDN-VANET mainly relies on DSRC road side units (RSUs) for V2I communication and to overcome the coverage problem SDN-VANET performs the vertical handover between DSRC and LTE/UMTS. To date there is no standard to perform network layer vertical handovers. Therefore the proposed SDN-VANET architecture also doesn't provide any mechanism for vertical network layer handovers, but solves the horizontal network layer handovers in DSRC or LTE/UMTS through introducing PMIPv6 in the architecture.

• International Journal of Computer Science & Network Security
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• 제21권3호
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• pp.165-171
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• 2021

Vehicular Ad hoc Network (VANET) is an extension paradigm of moving vehicles to communicate with wireless transmission devices within a certain geographical limit without any fixed infrastructure. The vehicles have most important participation in this model is usually positioned quite dimly within the certain radio range. Fuzzy based multi-hop broadcast protocol is better than conventional message dissemination techniques in high-mobility VANETs, is proposed in this research work. Generally, in a transmission range the existing number of nodes is obstacle for rebroadcasting that can be improved by reducing number of intermediate forwarding points. The proposed protocol stresses on transmission of emergency message projection by utilization subset of surrounding nodes with consideration of three metrics: inter-vehicle distance, node density and signal strength. The proposed protocol is fuzzy MHB. The method assessment is accomplished in OMNeT++, SUMO and MATLAB environment to prove the efficiency of it.

• International Journal of Computer Science & Network Security
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• 제24권8호
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• pp.139-144
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• 2024

VANETs have become one of the most attractive research areas in the world of wireless networks in recent years. Indeed, vehicular networks have become capable of optimizing road traffic, which significantly reduces the number of accidents through notifications exchanged between nearby vehicles. The routing function based on the opportunistic algorithm is a critical part of the vehicle's communication system and will therefore be an ideal target for attacks that could aim to prevent alert messages from reaching their destination, and thus endanger human lives. The black hole attack is a major threat to the security of VANETs. The main idea of this paper focuses on the analysis of this type of attack in VANETs using Discrete-Time Markov Chains (DTMC). and deduce at the end the effect of the number of malicious nodes on the delivery rate in the network.

• Journal of Multimedia Information System
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• 제6권2호
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• pp.61-66
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• 2019

VANET (Vehicular Ad-hoc Network) is a mobile Ad-hoc Network which deals with the moving vehicles. VANET supports Intelligent Transport Systems (ITS) which is related to different modes of transport and traffic management techniques. VANETs enabled users to be informed and make them safer. VANET uses IEEE 802.11p standard wireless access protocol for communication. An important and necessary issue of VANET is to design routing protocols. In a network, communication takes place by the use of the routing protocols. There are mainly two types of communications used such as Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) in VANET. Vehicles can send and receive messages among them and also to and from infrastructure used. In this paper, AODV, DSR and DSDV are compared by analysing the results of simulation on various metrics such as average throughput, instant throughput, packet delivery ratio and residual energy. Findings indicates utilization of AODV and DSR is more applicable for these metrics as compared to DSDV. A network simulator (NS2) is used for simulation.

• 한국통신학회논문지
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• 제40권1호
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• pp.152-164
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• 2015

최근 반도체 기술, 센서 기술 및 이동통신 기술의 발전으로 스마트 자동차 기술 연구 개발이 진행 중에 있다. 사회가 발전함에 따라 차량이 증가하였고 사고에 대한 위험은 점차 높아지고 있다. 그에 따라 기존의 차량용 블랙박스 외에 차량의 각종 센서 정보를 활용하여 운전자에게 다양한 정보를 제공하는 첨단 운전자 보조 시스템이 연구되고 있다. 본 논문에서는 차량 간의 통신기능을 포함하고, 주변의 정보를 습득하여 제공할 수 있는 스마트 카메라 장치를 설계 및 구현하여, 장치에 포함된 카메라로부터 입력 받은 영상을 분석하여 획득한 정보를 영상 메타데이터화 하는 기술에 대한 연구를 수행하였다. 또한 임베디드 장치의 제한된 계산 성능을 보완하기 위해 관심영역을 설정하는 S-ROI(Static-Region Of Interest), D-ROI(Dynamic-Region Of Interest) 방식을 고안하였다. 실험을 통해 영상처리 속도가 전체영상 분석에 비해 S-ROI의 경우 3.0배, D-ROI의 경우 4.8배 향상함을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권4호
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• pp.1624-1647
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• 2020

Vehicular network is one of the most important subjects for researchers in recent years. Anycast routing protocols have many applications in vehicular ad hoc networks. The aim of an anycast protocol is sending packets to at least one of the receivers among candidate receivers. Studies done on anycast protocols over vehicular networks, however, have capability of implementation on some applications; they are partial, and application specific. No need to say that the lack of a comprehensive study, having a strong analytical background, is felt. Mathematical modeling in vehicular networks is difficult because the topology of these networks is dynamic. In this paper, it has been demonstrated that vehicular networks can be modeled based on time-expanded networks. The focus of this article is on geographical anycast. Three different scenarios were proposed including sending geographic anycast packet to exactly-one-destination, to at-least-one-destination, and to K-anycast destination, which can cover important applications of geographical anycast routing protocols. As the proposed model is of MILP type, a decentralized heuristic algorithm was presented. The evaluation process of this study includes the production of numerical results by Branch and Bound algorithm in general algebraic modeling system (GAMS) software and simulation of the proposed protocol in OMNET++ simulator. The comprehension of the result of proposed protocol and model shows that the applicability of this proposed protocol and its reactive conformity with the presented models based on presented metrics.

• 디지털융복합연구
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• 제10권9호
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• pp.325-332
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• 2012

VANET(Vehicular Ad-hoc Network)는 차량 간 네트워크를 구성하는 기술로 전송 노드 기준으로 전송 범위내의 이웃 노드들의 정보를 이용하여 목적지까지의 경로를 설정한다. 지리적 정보를 이용한 기존의 라우팅 프로토콜은 송신 노드 기준으로 중계 노드 및 목적지 노드까지 거리만 고려하기 때문에 통신에 필요한 노드의 밀도가 충분하지 못하면 네트워크 지연 및 단절을 초래할 수 있다. 이러한 문제점을 해결하기 위해 본 논문에서는 도시 기반의 VANET 환경에서 차량 간 안정적인 통신을 위해 구역 기반의 라우팅 알고리즘을 제안한다. 실제 도시 환경을 구역으로 나누고 목적지까지 거리뿐만 아니라 차량 밀도를 고려하여 최적의 통신 환경을 선택함으로써 패킷 손실률을 최소화 하였다. 성능을 평가하기 위해 구현한 결과 기존 연구 결과 보다 우수한 성능 결과를 보였다.

• 한국산학기술학회논문지
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• 제8권3호
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• pp.593-600
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• 2007

본 논문에서는 도로망의 사정에 따라 변화될 수 있는 자동차 애드 혹 망 성능을 연구하기 위하여 도로망을 구성하고 라우팅 프로토콜별로 적용하여 성능을 비교분석하였다. 적용한 라우팅 프로토콜은 MANET(Mobile Ad-Hoc Network)인 AODV(Ad-hoc On-Demand Distance Vector)와 DSR(Dynamic Source Routing) 프로토콜이다. AODV는 일반적으로 DSR보다 성능이 우수한 것으로 알려져 있으나 애드 혹 도로망에서 자동차의 수가 많아질 경우에는 DSR 프로토콜이 성능 면에서 비슷하거나 오히려 우세하다는 결과를 얻을 수 있었다. 시뮬레이션을 위하여 왕복 4차선을 OPNET에서 구현하고 실행하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권12호
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• pp.3416-3435
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• 2023

Task offloading in vehicular networks is hot topic in the development of autonomous driving. In these scenarios, due to the role of vehicles and pedestrians, task characteristics are changing constantly. The classical deep learning algorithm always uses a pre-trained neural network to optimize task offloading, which leads to system performance degradation. Therefore, this paper proposes a neural network fine-tuning task offloading algorithm, combining with location prediction for pedestrians and vehicles by the Payne model of fluid dynamics and the car-following model, respectively. After the locations are predicted, characteristics of tasks can be obtained and the neural network will be fine-tuned. Finally, the proposed algorithm continuously predicts task characteristics and fine-tunes a neural network to maintain high system performance and meet low delay requirements. From the simulation results, compared with other algorithms, the proposed algorithm still guarantees a lower task offloading delay, especially when congestion occurs.

• 한국정보과학회논문지:정보통신
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• 제37권2호
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• pp.157-161
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• 2010

Vehicular Ad-Hoc Network(VANET)에서는 차량의 높은 이동성으로 인하여 빈번한 네트워크 단절이 일어난다. 본 논문에서는 이런 문제를 해결하기 위해 차량 밀도에 기반을 둔 경로 선택 알고리즘과 최소 홉 수를 유지하면서 end-to-end 패킷 전송 비율을 높이는 라우팅 알고리즘을 제시한다. 또한 교차로 근처에서 패킷을 전송할 때 건물로 인한 Packet Error Rate을 줄이는 다음 홉 노드 선택 알고리즘을 소개한다. 시뮬레이션 통하여 제안 알고리즘이 GPSR(Greedy Perimeter Stateless Routing for Wireless Networks)에 버퍼를 두어 패킷을 carry하도록 수정한 알고리즘보다 성능이 향상 된 것을 확인하였다.