• Proceedings of the KOR-KST Conference
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• 2000.02a
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• pp.25-47
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• 2000

In route guidance systems fastest-path routing has typically been adopted because of its simplicity. However, empirical studies on route choice behavior have shown that drivers use numerous criteria in choosing a route. The objective of this study is to develop computationally efficient algorithms for identifying a manageable subset of the nondominated (i.e. Pareto optimal) paths for real-time vehicle routing which reflect the drivers' preferences and route choice behaviors. We propose two pruning algorithms that reduce the search area based on a context-dependent linear utility function and thus reduce the computation time. The basic notion of the proposed approach is that ⅰ) enumerating all nondominated paths is computationally too expensive, ⅱ) obtaining a stable mathematical representation of the drivers' utility function is theoretically difficult and impractical, and ⅲ) obtaining optimal path given a nonlinear utility function is a NP-hard problem. Consequently, a heuristic two-stage strategy which identifies multiple routes and then select the near-optimal path may be effective and practical. As the first stage, we utilize the relaxation based pruning technique based on an entropy model to recognize and discard most of the nondominated paths that do not reflect the drivers' preference and/or the context-dependency of the preference. In addition, to make sure that paths identified are dissimilar in terms of links used, the number of shared links between routes is limited. We test the proposed algorithms in a large real-life traffic network and show that the algorithms reduce CPU time significantly compared with conventional multi-criteria shortest path algorithms while the attributes of the routes identified reflect drivers' preferences and generic route choice behaviors well.

• Journal of Information Processing Systems
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• v.13 no.3
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• pp.618-629
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• 2017

Mobile nodes can't always connect each other in DTNs (delay tolerant networks). Many DTN routing protocols that favor the "multi-hop forwarding" are proposed to solve these network problems. But they also lead to intolerant delivery cost so that designing a overhead-efficient routing protocol which is able to perform well in delivery ratio with lower delivery cost at the same time is valuable. Therefore, we utilize the small-world property and propose a new delivery metric called multi-probability to design our relay node selection principles that nodes with lower delivery predictability can also be selected to be the relay nodes if one of their history nodes has higher delivery predictability. So, we can find more potential relay nodes to reduce the forwarding overhead of successfully delivered messages through our proposed algorithm called HESnW. We also apply our new messages copies allocation scheme to optimize the routing performance. Comparing to existing routing algorithms, simulation results show that HESnW can reduce the delivery cost while it can also obtain a rather high delivery ratio.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.213-224
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• 2009

Most of existing routing methods in wireless sensor networks to counter the local eavesdropping-based packet-tracing deal with a single asset and suffer from the packet-delivery latency as they prefer to take a separate path of many hops for each packet being sent. Recently, the author proposed a routing method, GSLP-w(GPSR-based Source-Location Privacy with crew size w), that enhances location privacy of the packet-originating node(i.e., active source) in the presence of multiple assets, yet taking a path of not too long. In this paper, we present a refined routing(i.e., next-hop selection) procedure of it and empirically study privacy strength and delivery latency with varying the crew size w(i.e., the number of packets being sent per path). It turns out that GSLP-w offers the best privacy strength when the number of packets being sent per path is randomly chosen from the range [$1,h_{s-b}/4$] and that further improvements on the privacy are achieved by increasing the random walk length TTLrw or the probability prw that goes into random walk(where, $h_{s-b}$ is the number of hops of the shortest path between packet-originating node s and sink b).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.2
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• pp.649-663
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• 2012

We propose a percolation based M2M networking architecture and its data transmission method. The proposed network architecture can be server-free and router-free, which allows us to operate routing efficiently with percolations based on six degrees of separation theory in small world network modeling. The data transmission can be divided into two phases: routing and data transmission phases. In the routing phase, probe packets will be transmitted and forwarded in the network thus multiple paths are selected and performed based on the constriction of the maximum hop number. In the second phase, the information will be encoded, say, with the fountain codes, and transmitted using the paths generated in the first phase. In such a way, an efficient routing and data transmission mechanism can be built, which allow us to construct a low-cost, flexible and ubiquitous network. Such a networking architecture and data transmission can be used in many M2M communications, such as the stub network of internet of things, and deep space networking, and so on.

• Journal of the Korea Society of Computer and Information
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• v.8 no.1
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• pp.114-119
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• 2003

An efficient QoS routing scheme for improving on-line games services needs to find a path that satisfies a given noS requirements while consuming as few resources as possible. In this paper, we propose a scheme of calculating resources' costs for precomputation QoS routing schemes. For a domain in the networks. the routing scheme first precomputes K multiple paths between all pairs of ingress and egress border routers while considering balancing of the expected load. We. therefore, expect that the paths are better than any other paths in respect to reserving the network resources on paths. The routing scheme combines inter and intra domain routings seamlessly and uses the same cost calculation scheme.

• The Journal of the Korea Contents Association
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• v.7 no.9
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• pp.100-107
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• 2007

This paper proposes and efficient routing scheme named MP-DD(MultiPath-Direct Diffusion) which are simple enough to be applicable to the wireless sensor networks. Conventional DD(Direct Diffusion) uses only one optimal path, therefore it consumes more energy of specific nodes. MP-DD uses multiple path and has a information of hop upstream node in the direction of the base-station. Simulation results show that the proposed scheme can increase network survivability compared to conventional DD and EAR(Energy Aware Routing) schemes.

• Journal of the Korean Operations Research and Management Science Society
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• v.21 no.1
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• pp.101-114
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• 1996

This study suggests an accelerated genetic algorithm for the vehicle routing problem (AGAVRP). This algorithm treats both the single-visit and the multiple-visit models. AGAVRP is accelerated by the OR techniques at the various stages of the algorithm. In order to improve the convergence of AGAVRP, a robust set of parameters is determined by the experimental design approach. The relative performance of AGAVRP is comparable to the other known algorithms. The advantage of the proposed algorithm is flexibility and better convergence.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.569-571
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• 1995

This paper compares the simulated annealing and the Hopfield neural network method for an optimal routing in a multistage interconnection network(MIN). The MIN provides a multiple number of paths for ATM cells to avoid cell conflict. Exhaustive search always finds the optimal path, but with heavy computation. Although greedy method sets up a path quickly, the path found need not be optimal. The simulated annealing can find an sub optimal path in time comparable with the greedy method.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.383-393
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• 2007

We present a new network-layer architecture that provides generalized addressing. The forwarding infrastructure is independent of the addressing architecture, so multiple addressing architectures can be used simultaneously. We compare our solution with the existing Internet protocols for unicast and multicast services, given the address assignment used in the Internet. By means of an extensive simulation study, we determine the range of parameters for which the overhead costs(delay, state, and network load) of our service are comparable to those of the Internet.

• Journal of Korea Multimedia Society
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• v.24 no.8
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• pp.1068-1075
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• 2021

Wireless sensor network (WSN) can be usefully used in battlefields requiring rapid installation and operation by enabling surveillance and reconnaissance using small sensors in areas where any existing network infrastructure is not formed. As WSN uses battery, energy efficiency acts as a very important issue in network survivability. Layer-based routing protocols have been studied a lot in the aspect of energy efficiency. Many research selected LEACH and PEGASIS protocols as their comparison targets. This study examines the two protocols and LECEEP, a protocol designed by combining their advantages, and proposes a new protocol, A-LECEEP, which is more energy efficient than the others. The proposed protocol can increase energy efficiency compared to the existing ones by eliminating unnecessary transmissions with multiple chains configuration.