• Journal of Korea Multimedia Society
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• v.16 no.2
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• pp.180-189
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• 2013

The SMART Highway project combines road construction with advanced technology and vehicle telecommunications. Its expected outcome is a world-leading intelligent road that is green, fast, and comfortable. A vehicular ad-hoc network(VANET) is the core technology of the SMART Highway, whose transport operation is based on road vehicles. The VANET is a next-generation networking technology that enables wireless communication between vehicles or between vehicles and a road side unit(RSU). In the VANET system, a vehicle accident is likely to cause a serious disaster. Therefore, some information on safety is essential to serve as the key exchange protocol for communication between vehicles. However, the key exchange scheme of the general network proposed for a fast-moving communication environment is unsuitable for vehicles. In this paper, communication between multiple vehicles more efficient and secure key exchange at the vehicle certification by signcryption is proposed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2309-2315
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• 2013

VANET(Vehicular Ad-hoc Network) is getting attention as an application to improve driver safety through inter-vehicle communication. For activation of VANET, privacy-preserving mutual authentication has to be guaranteed. In previous works, authors proposed various group-based authentication protocols. However, risks on ID exposure due to repeated use of group key and RSU(Road Side Unit) DoS attack were not considered. In this paper, we propose a probabilistic approach for robust anonymous authentication protocol. We evaluated our proposed method in a sets of criteria in VANET and verified it is an efficient solution for enhancing privacy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.703-712
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• 2015

This paper proposes the UIGRP, which can tackle the problem of the network disconnection and packet transmission delay caused by turning vehicles frequently in an urban intersection. The UIGRP was designed as follows. First, it calculates the direction of vehicles using the moving direction of vehicles and the location of a destination. Second, it makes the RSU measure the density of an urban intersection. Third, the TGF Algorithm in the UIGRP decides the data transmission paths by setting as an intermediate node, not only the vehicle that is moving in the direction where a destination node is located, but also the node that has the highest density. The TGF algorithm using a moving direction and density minimizes or removes the occurrence of local maximum problems that the existing Greedy Forwarding algorithm has. Therefore, the simulation result shows that UIGRP decreases the occurrence of local maximum problems by 3 and 1 times, and the packet transmission time by 6.12 and 2.04(ms), and increases the success rate of packet transmission by 15 and 3%, compared to the existing GPSR and GPUR.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.136-141
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• 1989

A raw starch-digesting enzyme from Streptomyces sp. 4M-2 was purified by ammonium sulfate fractionation, DEAE-Sephadex A-50 column chromatography and Sephadex G-100 gel filtration. The specific activity of the purified enzyme was 51.22 RSU/mg protein and the yield was 4.5% of the total activity of the culture broth. The purified enzyme was found to be homogeneous by polyacrylamide gel electrophoresis and its molecular weight was estimated to be about 102, 000 daltons by SDS-polyacrylamide gel electrophoresis, The optimal temperature and pH for the enzyme activity were 42$^{\circ}C$ and PH 5.5, respectively. The enzyme had Km, value of 44.44mg/$m\ell$ for raw corn starch. The enzyme was activated by addition of calcium and barium ions. Corn amylose was degraded by the enzyme very easily and raw potato starch was also degraded easily. Main products of the enzymatic hydrolysis of raw corn starch were analyzed to be maltose and maltotriose. The enzyme was considered as $\alpha$-amylase.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.428-432
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• 2011

차량 통신 네트워크(VANET, Vehicle Ad hoc NETwork)는 ITS(Intelligent Transport System)의 발전과 함께 운전자의 안전 및 교통 정보, 긴급 메시지 등과 같은 서비스를 실시간으로 가능하게 할 수 있는 차세대 네트워크 기술이다. 이러한 차량 통신 네트워크는 현재 IEEE P1609에서 정의하고 있으며, WAVE(Wireless Access Vehicular Environment)로 알려져 있다. WAVE는 차량에 설치된 OBU(Onboard Unit)와 주변시설에 설치된 RSU(Road Side Unit)을 통하여 통신하며, 차량 간 통신을 지원하는 V2V(Vehicle to Vehicle)와 차량과 주변시설과의 통신을 지원하는 V2I(Vehicle to Infrastructure)로 나뉘어져 있다. 하지만 WAVE에서 정의하고 있는 네트워크 서비스(IEEE P1609.4)는 OBU와 RSU 간의 네트워크 서비스에 초점을 맞추고 있기 때문에 전체 네트워크의 QoS를 보장하기에는 미흡한 상태이다. 따라서 본 논문에서는 차량 통신 네트워크에서 End-to-End 간의 QoS 보장을 위한 무선 메쉬 네트워크 기반의 라우팅 알고리즘을 제안한다. 제안하는 알고리즘은 무선 메쉬 네트워크 노드의 호스트 라우터 기능을 통하여 차량 노드와 이기종 간의 네트워크 서비스를 가능하게 하며, 무선 메쉬 네트워크의 다중 채널을 이용하여 데이터의 중요도에 따른 차등 서비스를 지원한다. ns-2를 이용한 시뮬레이션 결과 제안하는 알고리즘이 QoS를 보장함으로써 차량 통신 네트워크의 성능을 향상시킬 수 있음을 입증하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.9
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• pp.578-589
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• 2014

In this paper, we introduce the concept of cyber-physical intersection systems (CPIS) which interconnects roadside units (RSU) located at the intersection, on-board units (OBU) of moving vehicles, and the smartphone apps, named the Smartphone Agent (SA). At the pedestrian mode of the SA, the connectivity management schemes, such as a location update and a handover control algorithm, are proposed to better support the CPIS services while minimizing the power consumption of the pedestrian's smartphone. We develop a real prototype of the CPIS, including RSU, OBU, and the SA. Based on the numerical results collected from a pedestrian moving around the Pusan National University campus, we validate that the proposed connectivity management schemes can improve not only the power efficiency of the pedestrian's smartphone, but also the quality of the CPIS services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.8
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• pp.544-554
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• 2014

In this paper, we introduce a cyber-physical intersection systems (CPIS) which intimately interconnects roadside units (RSU) located at intersection, on-board units (OBU) of moving vehicles, and smartphone apps. Based on the architecture of CPIS, we also present a green light optimal speed advisory based on the reference mobility models (GLOSA-RMM) to reduce intersection stopping time (IST) and fuel consumption. Based on several reference mobility models, the GLOSA-RMM determines the appropriate speed advisory by taking into account the current mobility and the intersection traffic light status, and then provides screen/voice GLOSA instructions to minimize the driver's distraction. We show that the GLOSA-RMM can reduce both the IST and the fuel consumption through the numerical results obtained from the prototype of the CPIS consisting of the OBU, the RSU and the smartphone app.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.239-248
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• 2012

VANET (Vehicular Ad-hoc Network) is a type of MANET (Mobile Ad-hoc Network) which is the next-generation networking technology to provide communication between vehicles or between vehicle and RSU (Road Side Unit) using wireless communication. In VANET system, a vehicle accident is likely to cause awful disaster. Therefore, in VANET environment, authentication techniques for the privacy protection and message are needed. In order to provide them privacy, authentication, and conditional, non-repudiation features of the group signature scheme using a variety of security technologies are being studied. In this paper, and withdrawal of group members to avoid frequent VANET environment is suitable for vehicles produced by the group administrator for a private signing key to solve the key escrow problem of a group signature scheme is proposed. We proposed a message batch verification scheme using Bloom Filter that can verify multiple messages efficiently even for multiple communications with many vehicles.

• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.68-79
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• 2021

On the Social Internet of Things (SIoT), social activities occur through which the vehicle generates a variety of data, shares them with other vehicles, and sends and receives feedbacks. In order to share reliable information between vehicles, it is important to determine the reliability of a vehicle. In this paper, we propose a vehicle trust evaluation scheme to share reliable information among vehicles. The proposed scheme calculates vehicle trust by considering user reputation and network trust based on inter-vehicle social behaviors. The vehicle may choose to scoring, ignoring, redistributing, etc. in the social activities inter vehicles. Thereby, calculating the user's reputation. To calculate network trust, distance from other vehicles and packet transmission rate are used. Using user reputation and network trust, local trust is calculated. It also prevents redundant distribution of data delivered during social activities. Data from the Road Side Unit (RSU) can be used to overcome local data limitations and global data can be used to calculate a vehicle trust more accurately. It is shown through various performance evaluations that the proposed scheme outperforms the existing schemes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.280-285
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• 2021

When VNDN technology is used as a communication technology for infotainment application services of connected vehicles, it is possible to realize data-centric networking technology in which data is the subject of communication.Vehicle security attacks and hacks, performance degradation during long-distance data transmission, and frequent data loss It is possible to innovate the limitations of the current host-oriented Internet-based infotainment application service technology of connected vehicles. The data packet forwarding issue to deliver critical information data that is very sensitive to delay in the VNDN on a push-based basis to RSU (Road Side Unit), etc. is one of the issues to be solved for realizing VNDN-based application services. We comprehensively analyze existing forwarding techniques to support push-based data traffic under the environment, and compare and analyze each technique in terms of performance.