• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.699-701
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• 2010

스마트폰, PDA와 같은 다양한 무선통신 단말들이 출현하면서 차량 내에서도 인터넷 서비스를 사용하려는 사용자들이 증가하고 있다. 이에 따라 이동중인 차량 내에서 인터넷 엑세스를 위해, 그리고 차량이 다른 서브넷 사이를 이동하더라도 시그널링 오버헤드가 크지 않게 하기 위해, network mobility basic support (NEMO BS) protocol이 제안되었다. 그러나 차량 내의 노드들에게 QoS를 지원하기 위해서 session admission 기법 등이 필요하다. 이 때, 차량 내에서 발생하는 세션은 new session과 handoff session으로 구분할 수 있는데, new session의 봉쇄보다 handoff session의 봉쇄가 서비스 만족도 측면에서 더 큰 임팩트를 가진다. 따라서 본 논문에서는 차량 외부에서 차량으로 이동한 노드들의 handoff session 봉쇄확률을 줄이기 위한 늦은 바인딩 업데이트 기법을 제안한다.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.4
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• pp.1-5
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• 2010

To operate safely VANET applications, authenticaton is necessary to identify val d participants and prevent malicious parties from modifying messages. This paper proposes an efficient authentication protocol for the vehicle registration in VANET environment. The topology of VANET changes rapidly due to high-speed movement of vehicles, thus it is need to reduce the computational burden of the authentication protocol. Therefore, this protocol uses only one-way hash functions and EOR operations to register vehicles.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.315-316
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• 2009

차량용 네비게이션에 사용되는 지도는 새로운 도로를 추가하거나 폐쇄된 도로를 삭제하는데 어려움을 겪는다. 이는 네비게이션 벤더에 의해 변경된 도로가 업데이트 되기 때문인데 벤더가 변경된 도로를 알아내기 위해서는 실제로 도로를 조사하는 등의 경비가 소모되므로 잦은 업데이트가 어렵다. 이런 문제를 해결하기 위해서 본 논문에서는 블루투스를 이용한 차량간 애드혹 네트워크를 이용해서 실시간으로 주변 도로의 형태를 생성하는 방법을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.51-52
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• 2009

본 논문에서는 차량 내의 네트워크 가운데에서 대용량의 멀티미디어 데이터를 전송할 수 있는 MOST(Media Oriented Systems Transport) 네트워크 기반의 오디오 인포테인먼트 인터페이스 개발에 관한 연구를 수행하였다. 구현한 오디오 인포테인먼트 인터페이스는 MOST 네트워크 인터페이스 컨트롤러로 OS81050A INIC 칩을 사용하였으며, EHC 부분은 ATmega128L 8bit 마이크로컨트롤러를 사용하였다. 오디오 동작과 관련된 기능 블록(FBlock) 및 애플리케이션 작성에는 NetServices API를 활용하였다. 구현된 인터페이스는 MOST 네트워크 분석 도구인 OptoLyzer G2를 이용하여 정확한 동작여부를 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.889-890
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• 2011

VANET(Vehicular Ad-hoc Network)의 V2V 통신의 경우 차량 간의 안전한 통신을 위해 차량 인증 및 조건부 프라이버시 보호를 제공하기 위해서 그룹 서명 기법을 사용한 보안 기술들이 다양하게 연구되고 있다. 하지만 VANET은 MANET과 달리 빠른 이동성을 가지는 노드의 특성상 그룹 구성원의 가입과 탈퇴가 빈번하다는 문제점을 가지고 있다. 본 논문에서는 그룹 구성원의 빈번한 가입과 탈퇴를 방지하기 위해 VANET 환경에 적합하고, 그룹 관리자에 의해 생성되는 차량 개인서명키에 대한 키 위탁문제를 해결하기 위한 그룹서명방식을 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6A
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• pp.609-616
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• 2011

The Delay/Disruption Tolerant Network (DTN) is a network designed to operate effectively using the mobility and storage of intermediate nodes under no end-to-end guaranteed network. This new network paradigm is well-suited for networks which have unstable path and long latencies (e.g. interplanetary network, vehicular network). In this paper, we first found that each taxi has its own regularly visiting area and define this property as spatial regularity. We analyze 4000 taxi trace data in Shanghai and show the existence of spatial regularity experimentally. Based on a spatial regularity in urban environment, we present a new DTN routing method. We introduce a Weighted Center (WC) which represents spatial regularity of each node. Through the association with evenly distributed access points (APs) in urban environment, most of vehicles get their grid locations and calculate their WCs. Since our routing method only uses neighbors' WCs for building routing paths, it can be regarded as distributed and practical protocols. Our experiments involving realistic network scenarios created by the traces of about 1500 Shanghai taxies show that our routing method achieves the higher performance compared to ECT, LET by 10%~110%.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.3
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• pp.193-198
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• 2016

Lane change is an important issue in microscopic traffic flow simulations and active safety. Overtaking and changing lanes are dangerous driving maneuvers. This approach presents a lane-changing system based on speed and a minimum gap between vehicles in a vehicular ad hoc network (VANET). This paper proposes a solution to ensure the safety of drivers while changing lanes on highways. Efficient routing protocols could play a crucial role in VANET applications, safeguarding both drivers and passengers, and thus, maintaining a safe on-road environment. This paper focuses on the development of an intelligent transportation system that provides timely, reliable information to drivers and the concerned authorities. A test bed is created for the techniques used in the proposed system, where analysis takes place in an on-board embedded system designed for vehicle navigation. The designed system was tested on a four-lane road in Neemrana, India. Successful simulations were conducted with real-time network parameters to maximize quality of service and performance using Simulation of Urban Mobility and Network Simulator 2 (NS-2). The system implementation, together with the findings, is presented in this paper. Illustrating the approach are results from simulation using NS-2.

• The KIPS Transactions:PartC
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• v.14C no.6
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• pp.503-508
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• 2007

Since the Wibro service realize mobile network on the public, it has been considered that it is not enough to support real time service at vehicular speed. The standard Fast Mobile IPv6 Handover Protocol using HMIPv6 may guarantee seamless service as long as the Mobile Node moves in the same domain MAP however it does not regard fast handover over inter-MAP domain. Thus Macro Mobility Handover in HMIPv6 was proposed to reduce handover latency in inter-MAP domain. But it is still not enough to support real-time service. So we propose an Improved FHMIPv6 over 802.16e network to reduce the overall handover latency. We embedded Layer 3 handover messages of the FHMIPv6 into the Layer 2 handover messages. So the MN is able to $^-nish$ overall handover procedure earlier in our scheme. The numerical results show the performance of IFHMIPv6 has improved about 32% in comparison with FHMIPv6.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2008-2015
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• 2010

Ns-2 is a proven simulator which is widely utilized to evaluate the performance of wired and wireless network. Ns-2.33 version introduced the extended version including the modules which the core functions of existing 802.11 PHY and MAC layer are implemented. However, if the error rate, one of most important parameters to evaluate a performance of wireless network, is applied to the extended version, the simulation is ceased with several fatal errors. Furthermore, a packet error is detected and discarded on MAC layer in the traditional protocol architecture, but there is the problem which can't identify information about a packet with error by processing packet error on PHY layer in this version. In this paper, we modify the extended version to resolve the above mentioned problems. And also we perform ns-2 simulation using the modified version on the IEEE 802.11p based vehicular ad-hoc networks, and then analyze effects of error rate.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.9
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• pp.4228-4247
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• 2018

Many methods have been developed for the vehicles to create clusters in vehicular ad hoc networks (VANETs). Usually, nodes are vehicles in the VANETs, and they are dynamic in nature. Clusters of vehicles are made for making the communication between the network nodes. Cluster Heads (CHs) are selected in each cluster for managing the whole cluster. This CH maintains the communication in the same cluster and with outside the other cluster. The lifetime of the cluster should be longer for increasing the performance of the network. Meanwhile, lesser the CH's in the network also lead to efficient communication in the VANETs. In this paper, a novel algorithm for clustering which is based on the social behavior of Gray Wolf Optimization (GWO) for VANET named as Intelligent Clustering using Gray Wolf Optimization (ICGWO) is proposed. This clustering based algorithm provides the optimized solution for smooth and robust communication in the VANETs. The key parameters of proposed algorithm are grid size, load balance factor (LBF), the speed of the nodes, directions and transmission range. The ICGWO is compared with the well-known meta-heuristics, Multi-Objective Particle Swarm Optimization (MOPSO) and Comprehensive Learning Particle Swarm Optimization (CLPSO) for clustering in VANETs. Experiments are performed by varying the key parameters of the ICGWO, for measuring the effectiveness of the proposed algorithm. These parameters include grid sizes, transmission ranges, and a number of nodes. The effectiveness of the proposed algorithm is evaluated in terms of optimization of number of cluster with respect to transmission range, grid size and number of nodes. ICGWO selects the 10% of the nodes as CHs where as CLPSO and MOPSO selects the 13% and 14% respectively.