• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.110-113
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• 2022

인터넷을 통해 주위 사물과 연결된 차량은 사용자에게 편리성을 제공하기 위해 다양한 콘텐츠를 요구하는데 클라우드로부터 가져오는 시간이 비교적 오래 걸리기 때문에 차량과 물리적으로 가까운 위치에 캐싱하는 기법들이 등장하고 있다. 본 논문에서는 기반 시설이 밀집하게 설치된 도시 환경에서 maximum distance separable(MDS) 코딩을 사용해 road side unit(RSU)에 캐싱하는 방법에 대해 연구하였다. RSU의 중복된 서비스 커버리지 지역을 고려하여 차량의 콘텐츠 요구에 대한 RSU hit ratio를 높이기 위해 deep Q-learning(DQN)를 사용하였다. 실험 결과 비교 알고리즘보다 hit raito 측면에서 더 높은 성능을 보이는 것을 증명하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1969-1977
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• 2016

We study the connection time of vehicle-to-mobile roadside unit (V2MR) communications which can reduce the significant cost of the fixed RSU by installing a gateway of mobile network into a transit bus called the mobile RSU. In the V2MR communications, the connectivity of a commute vehicle can be improved via ad-hoc connection to a nearby mobile RSU. In this paper, we present a new analysis model to estimate the connection time between a commute vehicle and a mobile RSU, when there is a bus station in the overlapping route. Since the connection time between two vehicles is highly dynamic and unpredictable, our analysis will provide a fundamental basis of connection-time estimation of V2MR communications. Numerical results obtained from VEINS simulation show that our analysis can estimate the connection time of V2MR communications with the average error below 1.0 percent. Moreover, we show that the average connection time of V2MR communications can be extended to approximately 3.85 times of that of V2R communications.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.495-498
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• 1998

본 논문에서는 요즘 많은 관심 속에서 활발히 연구되고 있는 WLL(wireless local loop)에서 이동국 (mobile station)과 FWT(fixed wireles sterminal)를 이용한 고정국 (RSU. Radio subscriber unit) 시스템의 구성을 제안한다. 이동국은 FWT로부터 분리하여 휴대사용할 수 있다는 점에서 일반적인 WLL 시스템의 고정국과 차이가 있다. 본 논문에서는 FWT의 하드웨어와 소프트웨어의 구성에 대하여 기술한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.485-492
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• 2010

Intelligent Transport System(ITS) has been studied in various systems, such as road environment information offering, vehicle short-range wireless/wire communication, vehicle collision preventing and pedestrian safety offering systems. Related to this, the USN technology based on the sensing accuracy for motorists and pedestrians safety, the information reliability, the maintenance and convenience for Sensor Network is highlighted. This study uses various sensors to construct USN to the road, and connect it to the developed RSU so it collects the real-time road environment information and offers it to OBU and Traffic Control Surveillance Center with Road Weather Information System. RSU collects roadside information for driver's safety and analyzes it to offer IP and beacon service according to the service priority to OBU & upper layer terminal. In the upper layer terminal it is developed the IP based Settop Box application program to offer the urban traffic information & road environment, and environment sensor error, etc. Finally, RWIS develops the real-time collection of roadside information to complement the driver's safety to the intelligent traffic system, and presents various service modes with technology convergence.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.115-124
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• 2008

In vehicular networks, vehicles should be able to authenticate each other to securely communicate with network-based infrastructure, and their locations and identifiers should not be exposed from the communication messages. however, when an accident occurs, the investigating authorities have to trace down its origin. As vehicles communicate not only with RSUs(Road Side Units) but also with other vehicles, it is important to minimize the number of communication flows among the vehicles while the communication satisfies the several security properties such as anonymity, authenticity, and traceability. In our paper, when the mutual authentication protocol is working between vehicles and RSUs, the protocol offers the traceability with privacy protection using pseudonym and MAC (Message Authentication Code) chain. And also by using MAC-chain as one-time pseudonyms, our protocol does not need a separate way to manage pseudonyms.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.75-87
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• 2010

Secure communication has been one of the main challenges in vehicular ad hoc networks(VANET) since broadcast messages from nearby vehicles contain life-critical information for drivers and passengers. So far various secure communication schemes have been proposed to secure the communication in VANET, and they satisfy most security requirements. However most of them need to put trust on roadside units(RSUs), which are usually deployed in unattended area and vulnerable to compromise. In this paper, we propose a secure communication scheme, which does not need to put trust on RSUs. And we adopt a grouping technique to averagely divide the huge burden in the server without jeopardizing the anonymity of users. Moreover we design a complete set of protocols to satisfy common security requirements with a relatively lower hardware requirement. At last, we evaluate the scheme with respect to security requirements, communication overhead, storage overhead and network performance.

• 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 the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2192-2198
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• 2012

VANET is a network environment which provides the communication between vehicles and between vehicle and RSU using wireless communication. VANET is very important to protect safety and life of people. Because of that, security is considered enough and certification is very important when messages exchanged between vehicles. Recently, Zhang proposed using Diffie-Hellman key exchange protocol that is method exchanging messages in VANET system through RAISE. But this is many problems on weakness from various attacks. In this paper, proposed the method that establish symmetric key using ECDH key exchange protocol and confirm safety and time spending that generate key and exchange through comparison.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2001.06a
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• pp.43-48
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• 2001

Many applications in the areas of agricultural, hydrological and environmental resource management require data over very large areas and with a high imaging frequency - monitoring crop growth, water stress, seasonal wetland flooding and natural vegetation development. This precludes the use of fine resolution data (Landsat, Spot) on the grounds of cost, accessibility and low imaging frequency. Meteorological satellites have the potential to fill this need, given their very wide spatial coverage, and high repeat imaging. The Remote Sensing Unit (RSU) at the Zambia Meteorological Department routinely receives, processes and archives imagery from both Meteosat and NOAA AVHRR satellites. Here I wish to present some examples of applications of these data sets that arise from the RSU work - relationships between rainfall and vegetation development as assessed by satellite, derived information and seasonal patterns of flooding in the Barotse floodplain and the Kafue flats. I also wish to outline ways in which a more widespread use of this data by the Zambian institutions canbe achieved.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.707-708
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• 2009

In this paper, we provide a tradeoff solution to two conflicting requirements in VANET; Privacy and Aggregation. The information about traffic density is an important factor of aggregation in VANET. In our proposed scheme, densely located Road-Side Units (RSU) perform traffic density calculation and then aggregate the traffic information extracted from beacons received from the vehicles. RSUs then disseminate the aggregated traffic information to all the vehicles and neighbor RSUs. We use identityless beaconing thereby providing privacy and we do not consider the content security of beacons. We show that our scheme provides privacy in the case of aggregation, which has not been considered in previous schemes.