• Journal of Digital Convergence
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• v.11 no.10
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• pp.379-385
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• 2013

MANET is not suitable to be applied to vehicle environments because of frequent path loss and path re-routing. To solve these problem, It is known that location-based routing protocol VANET is efficient. But, the VANET algorithm does not consider urban environments due to frequent vehicle movement and jamming by tall building. In this paper, we propose an efficient routing protocol to improve transfer efficiency and reduce transfer hop count. in urban networks.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.357-359
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• 2000

최근 들어 디지털(digital) 비디오나 오디오 같은 멀티미디어 응용 프로그램이 수요와 공급이 폭발적으로 늘어남에 따라, 이를 지원할 수 있는 새로운 프로토콜 아티텍쳐(architecture)들이 개발되고 있다. QoS(Quality-of-Service) 라우팅은 이러한 응용 프로그램들이 요구하는 QoS 요구사항을 기반으로 하는 라우팅(routing) 기법이다. QoS 라우팅은 네트워크의 동적인 상태를 반영하여 플로우(flow)가 요구하는 QoS를 만족시킬 수 있는 라우트를 찾아줌으로써 라우팅 성능을 향상시켰지만, 네트워크의 동적인 상태 정보를 모든 라우터가 가지고 있어야 함은 물론 적절한 시기에 네트워크 정보를 갱신시켜야만 한다. 이와 같이 네트워크 정보의 적절한 갱신 시기를 결정하는 것은 갱신 유발 정책이라 한다. 기존에는 라우팅 성능을 높이기 위해 네트워크 변화에 민감한 갱신 유발 정책을 사용하였으나, 이로 인해 발생하는 갱신 메시지는 또 하나의 트래픽(traffic)을 발생시켜 프로토콜 오버헤드(protocol overhead)를 초래하였다. 또한, 최근에는 이러한 프로토콜 오버헤드를 줄이기 위한 갱신 주기 정책이 제시되었지만 라우팅 성능 저하를 감수해야 하는 한계점이 발견되었다. 본 논문에서는 기존에 제시된 갱신 유발 정책에 비하여 프로토콜 오버헤드를 좀더 줄임과 동시에 라우팅 성능을 개선시킨 새로운 갱신 유발 정책을 제시하였다. 그리고, 이에 관한 시뮬레이션을 구현하여 프로토콜 오버헤드와 라우팅 성능을 비교한 결과, 기존 정책보다 더 효율적임을 발견하였다.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.71-73
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• 2004

Recently many peoples served multimedia data from Internet. But characteristic of multimedia-object about that effect on weight and transport-time causes Streaming Application is restricted to high-quality-service. This research propose the Quality-of-service(QoS) supporting for Home Gateway that behaving Routing and media platform equipment, using CBQ Scheduling scheme. The QoS Supporting for Multimeda Service that using general Rouging policy is difficult because media platform locate in Home Gateway. Therefore this research propose Routing mechanism to QoS support of media platform located in Gateway using TCP based CBQ Control.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.408-418
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• 2007

In this paper, we address the question of dynamic network provisioning for time-varying traffic rates, with the objective of maximizing the system throughput. We assume that the network is capable of providing bandwidth guaranteed traffic tunnels for an ingress-egress pair and present an approach that (1) updates the tunnel routes and (2) adjusts the tunnel bandwidths, in an incremental, adaptive manner, based on the variations in the incoming traffic. First, we consider a simpler scenario where tunnel routes are fixed, and present an approach for adjusting the tunnel bandwidths dynamically. We show, through simulations, that our dynamic bandwidth assignment algorithm significantly outperforms the optimal static bandwidth provisioning policy, and yields a performance close to that of the optimal dynamic bandwidth provisioning policy. We also propose an adaptive route update algorithm, which can be used in conjunction with our dynamic bandwidth assignment policy, and leads to further improvement in the overall system performance.

• Journal of KIISE:Information Networking
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• v.29 no.1
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• pp.65-76
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• 2002

QoS routing is a routing technique for finding feasible path that satisfies QoS requirements required by application programs. Since QoS routing determines such paths in terms of dynamic network state, it satisfies the requirement of applications and increases the utilization of the network. The overhead is, however, generated by routers to exchange the information of the dynamic state of network. In order to reduce this protocol overhead, a timer based update mechanism is proposed in which router checks the change of the network status periodically and network state information is exchanged if the change is greater than a certain value. Using large update period makes, though, routing performance irresponsive to the parameters which determine the update of the network state of the router. In addition to this, large update period may result in inaccurate network state information at routers and cause resource reservation failure. The resource reservation failure generates additional overhead to cancel the resource reservation of the part of the path. In this paper, we propose mechanisms enhancing the existing network state update policy with respect to these two problems. Performance of the proposed schemes are evaluated through a course of simulation.

• Journal of Digital Convergence
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• v.10 no.9
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• pp.325-332
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• 2012

VANET(Vehicular Ad-hoc Network), which is a technology to create a network among vehicles, decides the route to the destination using information of neighbors within the transmission range as transmission nodes. The existing routing protocol which uses geographical information can cause delay and disconnection of the network when the density of nodes is not high enough to communicate because it only considers the distance of the relay nodes or destination nodes from the source nodes. To solve the problem, this dissertation suggests a routing algorithm based on zones for stable communications among vehicles in the environment of VANET. I minimize the packet loss rate by dividing the city environment into zones and taking into account not only the distance of the destination but also the density of vehicles to choose the best communications environment. This results in a better performance than the established research when the performance evaluation is implemented.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.339-345
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• 2014

This study has a purpose that improves efficiency of energy management and adaptation followed by movement of node better than the various early studied routing techniques. The purpose of this paper is the technique that uses RSSI value and location of sensor that is received by each sensor node to routing. This sduty does not save node information of 1-hop distance. And it solves energy-inefficient traffic problem that happens during data exchange process for middle node selection in close range multi hop transmission technique. The routing protocol technique that is proposed in this study selects a node relevant to the range of transmission which is set for RSSI value that is received by each node and selects the closest node as a middle node followed by location data. Therefore, it is for not exhaustion of node's energy by managing energy efficiently and cutting data transmission consuming until the destination node.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.4
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• pp.425-434
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• 2010

This study shows a limit to attacks that the prevention system, which is used as the mutual third aggressive packet path between open heterogeneous networks and applies prevention techniques according to the trace like IP tracking and attack methods, can prevent. Therefore, the study aims to learn information of constant attack routing protocol and of the path in network, the target of attack and build a database by encapsulating networks information routing protocol operates in order to prevent source attack paths. In addition, the study is conducted to divide network routing protocols developed from the process of dividing the various attack characters and prevent various attacks. This study is meaningful in that it analyzes attack path network and attacks of each routing protocol and secure exact mechanism for prevention by means of 3D-Puzzle, Path, and Cube of the integrated security system which is an implementation method of integrated information protection for access network defense.

• Journal of Korean Society of Transportation
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• v.28 no.5
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• pp.91-106
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• 2010

Recently, interest in supply chain management is rising along with the increasing oil prices and traffic congestion. In particular, people started studying the issue, but realized that advantageous strategies for suppliers and retailers are not always advantageous to a carrier. Therefore, in this study the atuhors set up a simulation scenario to understand delivery vehicle routing problems under various inventory policies, namely Economic Order Quantity (EOQ) and Periodic Order Quantity (POQ) and network configurations. First, the authors made a virtual supply chain. Then they analyzed characteristics of delivery vehicle routing under various inventory policies (EOQ and POQ) and network configurations. As a result, the POQ inventory policy decreases the number of vehicles, the number of drivers, and the service time of vehicles. Also, the centralized network increases the load factor of vehicles and decreases the service time of vehicles. In other words, the centralized network and the POQ inventory policy are better for the carrier. These results show a savings of 15,556,806 won ($13,389.10) in a month: a reduction of 17%.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.3
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• pp.238-248
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• 2000

Facilities are getting more automated and informative in modern manufacturing systems, especially in semiconductor and LCD plants. These systems keep a great deal of such information on its current and near-future status as the arrival time and job completion time of their parts. This paper presents an efficient policy for AGV and part routing using information on the future status of the system where AGVs are playing a central role for material handling. Efficient control of AGVs is very important because AGV systems often become the bottleneck and limit the total production capacity of a very expensive plant. The cell controller records the future events chronologically in Next Event Schedule, and uses this list to determine to which place the AGVs and parts to be sent.