• Journal of Communications and Networks
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• v.3 no.4
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• pp.374-382
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• 2001

Nowadays, the commonly used table lookup scheme for IP routing is based on the sc-called classless interdomain routing (CIDR). With CIDR, routers must find out the best matching prefix (BMP) for IP packets forwarding, this complicates the IP lookup. Currently, this process is mainly performed in software and several schemes hale been proposed for hardware implementation. Since the IP lookup performance is a major design issue for the new generation routers, in this article we investigate the properties of the routing table and present a new approach for IP lookups, our approach is not based Gn BMP and significantly reduces the complexity, thus the computation cast of existing schemes can be significantly reduced. We also propose an efficient IP lookup algorithm, with which we improve the binary search on prefixes to 30 millions of packets per second (MPPS) and 5,000 route updates/s under the same experiment setup with an even larger routing table.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.51-53
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• 2009

In wireless sensor networks(WSNs), geographic routing algorithms can enhance the network capacity. However, in the real WSNs, it is difficult for each node to know its accurate physical location. Geographic routing with location error may have serious problems such as disconnected links and delayed data transmission. In this letter, we present an efficient location error detection scheme for geographic routing. The proposed algorithm can efficiently update its incorrect location without additional procedure and finally enhance the performance on the geographic routing with the location errors.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2362-2378
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• 2017

To mitigate the performance degradation caused by performance anomaly, a number of channel assignment algorithms have been proposed for multi-rate wireless mesh networks. However, network conditions have not been fully considered for routing process in these algorithms. In this paper, a joint scheme called Multi-rate Dijkstra's Shortest path - Rate Separated (MDSRS) is proposed, combining routing metrics and channel assignment algorithm. In MDSRS, the routing metric are determined through the synthesized deliberations of link costs and rate matches; then the rate separated channel assignment is operated based on the determined routing metric. In this way, the competitions between high and low rate links are avoided, and performance anomaly problem is settled, and the network capacity is efficiently improved. Theoretical analysis and NS-3 simulation results indicate that, the proposed MDSRS can significantly improve the network throughput, and decrease the average end-to-end delay as well as packet loss probability. Performance improvements could be achieved even in the heavy load network conditions.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.199-201
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• 2003

Ad hoc network은 stationary infrastructure의 도움 없이 이동 노드들이 필요 시 network 형태을 구성하여 통신이 이루어지게 하는 network으로 ad hoc network 환경에 맞는 다양한 라우팅 프로토콜들이 개발되었고 크게는 table­driven, on­demand 방식으로 나눌 수 있는데 on­demand 방식의 AODV 프로토콜은 routing overhead가 적다는 장점이 있는 반면 single path로 data forwarding을 진행하여 중간노드의 이동에 의한 path가 broken되는 경우 local routing을 하거나 새로이 source­initialed route rediscovery을 수행하여 전송 delay 및 control traffic overhead 등을 높이는 결과를 발생 시켰다. 본 논문은 single path로 구성되는 AODV 프로토콜의 route failures시 문제점을 보완한 Associativity Based Redundancy path Routing(ABRR) 및 Alternate Redundancy path Routing(ARR) schemes을 제안한다. 첫째, ABRR은 main path상에 있는 각 노드들은 associativity based stable node 정보를 이용하여 path broken 이전에 local redundancy path을 구성하여 path broken시 local routing없이 route을 복구할 수 있게 하고 둘째, ARR은 source­initialed route discovery에 의해 alternate path을 구성하여 ABRR 그리고 local routing에 의해 main route recovery 실패 시 alternate path을 main path로 전환하여 control traffic overhead 및 전송 delay을 줄이게 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2B
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• pp.69-75
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• 2008

We propose new routing scheme, Cooperative Diversity-based Routing (CDR)which utilize the cooperative space diversity for power saving and for performance enhancement of wireless ad-hoc networks. The end-to-end performance of the proposed routing, CDR, is analyzed based on the Haenggi's link model. The improved performance is compared with Multi-hop Relay Routing (MRR) by analytical methods. When the required outage probability is $1{\times}10^{-3}$ at the destination node in ad-hoc networks with 7 nodes, we noticed that each node can save power consumption by 21.5 dB in average, by using our proposed CDR compared to MRR.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.4
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• pp.369-376
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• 2005

In recent years, AGVs(Automated Guided Vehicles) have received growing attention as a subsystem of the integrated container operating system which enables unmanned control. improvement of job reliability, accuracy and productivity. Therefore, a number of works have been done to enhance the performance AGVs. In this paper. job deployment and a dynamic routing control system composed of supervisor, traffic controller. motion controller and routing table are discussed. A simple job deployment scheme and an efficient dynamic routing algorithm incorporating with the deadlock prediction and avoidance algorithm are investigated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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• pp.1113-1116
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• 2020

In the EH-WSN(Energy Harvesting Wireless Sensor Network), the routing protocol must consider the power condition of nodes such as residual power and energy harvesting rate. Many EH-WSN studies have emphasized the power aspect and make the urgency of sensed data less important. However, in applications such as environmental monitoring, stability and latency become more important issues than power efficiency for urgent data. In this paper, we designed a routing protocol that can set path according to data urgency. To this end, relay nodes are determined considering the urgency of date. Nodes with poor power do not participate in routing when normal data is generated, so that urgent data can be transmitted reliably with low latency. The performance of the proposed routing protocol is analyzed by computer simulation.

• Journal of KIISE:Databases
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• v.30 no.6
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• pp.629-640
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• 2003

A shared disk (SD) cluster couples multiple nodes for high performance transaction processing, and all the coupled nodes share a common database at the disk level. In the SD cluster, a transaction routing corresponds to select a node for an incoming transaction to be executed. An affinity-based routing can increase local buffer hit ratio of each node by clustering transactions referencing similar data to be executed on the same node. However, the affinity-based routing is very much non-adaptive to the changes in the system load, and thus a specific node will be overloaded if transactions in some class are congested. In this paper, we propose a dynamic transaction routing scheme that can achieve an optimal balance between affinity-based routing and dynamic load balancing of all the nodes in the SD cluster. The proposed scheme is novel in the sense that it can improve the system performance by increasing the local buffer hit ratio and reducing the buffer invalidation overhead.

• Journal of Advanced Navigation Technology
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• v.14 no.4
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• pp.495-503
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• 2010

The clustering is an important mechanism thai provides information for mobile nodes efficiently and improves the processing capacity for routing and the allocation of bandwidth. This paper proposes a clustering scheme based on the fuzzy relevance degree to solve problems such as node distribution found in the dynamic property due to mobility and flat structure and to enhance the routing performance. The proposed scheme uses the fuzzy relevance degree, ${\alpha}$, to select the cluster head for clustering in FSV (Fuzzy State Viewing) structure. The fuzzy relevance ${\alpha}$ plays the role in CH selection that processes the clustering in FSV. The proposed clustering scheme is used to solve problems found in existing 1-hop and 2-hop clustering schemes. NS-2 simulator is used to verify the performance of the proposed scheme by simulation. In the simulation the proposed scheme is compared with schemes such as Lowest-ID, MOBIC, and SCA. The simulation result showed that the proposed scheme has better performance than the other existing compared schemes.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.10a
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• pp.127-132
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• 1999

A mobile IP is proposed to support host mobility over the current Internet. One of the most important issues on the host mobility is location and routing schemes that allow mobile hosts to move effectively from one site to another. In a Mobile IP environment, frequent handoffs are likely to degrade the performance by minimizing the loss of datagrams during handoffs. The handoff scheme is using routing optimization and binding extension to improve the performance by minimizing the average transfer delay of messages and packet loss. Simulation details show the improvement of transport delays and packet loss rate.