• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.285-291
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• 2022

WSN is the major component for information transfer in IoT environments. Source Location Privacy (SLP) has attracted attention in WSN environments. Effective SLP can avoid adversaries to backtrack and capture source nodes. This work presents a Two-Level Randomized Sector-based Routing (TLRSR) model to ensure SLP in wireless environments. Sector creation is the initial process, where the nodes in the network are grouped into defined sectors. The first level routing process identifies sector-based route to the destination node, which is performed by Ant Colony Optimization (ACO). The second level performs route extraction, which identifies the actual nodes for transmission. The route extraction is randomized and is performed using Simulated Annealing. This process is distributed between the nodes, hence ensures even charge depletion across the network. Randomized node selection process ensures SLP and also avoids depletion of certain specific nodes, resulting in increased network lifetime. Experiments and comparisons indicate faster route detection and optimal paths by the TLRSR model.

• Journal of KIISE:Information Networking
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• v.35 no.4
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• pp.292-300
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• 2008

In multi-hop wireless networks like Wireless Mesh Networks (WMN) and Wireless Sensor Networks (WSN), nodes often rely on batteries as their power source. In such cases, energy efficient routing is critical. Many schemes have been proposed to find the most energy efficient path, but most of them do not achieve optimality on network lifetime. Once found, the energy efficient path is constantly used such that the energy of the nodes on the path is depleted quickly. As an alternative, the approaches that dynamically change the path at run time have also been proposed. These approaches, however, involve high overhead of establishing multiple paths. In this paper, we first find an optimal multi-path routing using LP. Then we apply an approximation algorithm to derive a near-optimal solution for single-path routing. We compare the performance of the proposed scheme with several other existing algorithms through simulation.

• Journal of Intelligence and Information Systems
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• v.15 no.3
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• pp.137-150
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• 2009

This paper proposes the hybrid heuristic method to apply the opportunity time to solve the vehicle routing and scheduling problem with time constraints(VRSPTW). The opportunity time indicates the idle time which remains after the vehicle performs the unloading service required by each customer's node. In this proposed heuristic, we add the constraints to VRSPTW model for the opportunity time. We also obtain the initial solution by applying the cost evaluation function to the insertion strategy considering the opportunity time. In addition, we improve the former result by applying the opportunity time to the tabu search strategy by swapping the customer's node. Finally, we suggest the construction strategies of initial routing which can efficiently acquire the nearest optimal solution from various types of data in terms of geographical condition, scheduling horizon and vehicle capacity. Our experiment show that our heuristic can get the nearest optimal solution more efficiently than the Solomon's I1 heuristic.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.299-310
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• 2016

In practical wireless relay communication systems, non-destination nodes are assumed to be idle not receiving signals while the relay sends messages to a particular destination node, which results in reduced bandwidth efficiency. To improve the bandwidth efficiency, we relax the idle assumption of non-destination nodes and assume that non-destination nodes may receive signals from sources. We note that the message relayed to a particular node in such a system gives rise to interference to other nodes. To study such a more general relay system, we consider, in this paper, a relay system in which the relay first listens to the source, then routes the source message to the destination, and finally produces interference to the destination in sending messages for other systems. We obtain capacity upper and lower bounds and study the optimal method to deal with the interference as well as the optimal routing schemes. From analytic results obtained, we find the conditions on which the direct transmission provides higher transmission rate. Next, we find the conditions, by numerical evaluation of the theoretical results, on which it is better for the destination to cancel and decode the interference. Also we find the optimal source power allocation scheme that achieves the lower bound depending on various channel conditions. We believe that the results provided in this paper will provide useful insights to system designers in strategically choosing the optimal routing algorithms depending on the channel conditions.

• Journal of KIISE:Information Networking
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• v.36 no.1
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• pp.1-11
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• 2009

In this paper, we propose a QoS routing protocol for WiMAX based wireless mesh networks. The proposed routing protocol is a proactive hop-by-hop QoS routing protocol. It can find an optimal route that satisfies QoS requirements using bandwidth and delay as QoS parameters. In this paper, we first present a network model for WIMAX based wireless mesh networks and explain why QoS routing protocol is the most appropriate for WiMAX based wireless mesh networks. Then, we propose a proactive hop-by-hop QoS routing protocol that meets QoS requirements of traffic flowing between mesh client and the gateway. The simulation results show that the proposed routing protocol outperforms QOLSR protocol in terms of end-to-end delay, packet delivery ratio and routing overhead.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.4
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• pp.274-279
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• 2002

ATM packet switching technologies for the purpose of the B-ISDN service are focused on high performance which represents good qualities on throughput, packet loss, and packet delay. ATM switch designs on a class of parallel interconnection network have been researched. But these are based on the self-routing function of it. It leads to conflict with each other, and to lose the packets. Therefore, this paper proposes the method based on Sort-Banyan network should be adopted for optimal routing algorithm. It is difficult to expect good hardware complexity. For good performance, a switch design based on the development of new routing algorithm is required. For the design of switch network, the packet distributor and multiplane are proposed. They prevent each packet from blocking as being transmitted selectively by two step distributed decision algorithm. This switch will be proved to be a good performance switch network that internal blocking caused from self-routing function is removed. Also, it is expected to minimize the packet loss and decrease the packet delay according to packet transmission.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.11
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• pp.1-6
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• 2010

In Sensor Networks, the problem of finding the optimal routing path dynamically, which passes through all terminals or nodes once per each, may come up. Providing a generalized scheme of approximations that can be applied to the kind of problems, and formulating the bounds of the run time and the results of the algorithm made from the scheme, one may evaluate mathematically the routing path formed in a given network. This paper, dealing with Euclidean TSP(Euclidean Travelling Sales Person) that represents such problems, provides the scheme for constructing the approximated Euclidean TSP by parallel computing, and the ground for determining the difference between the approximated Euclidean TSP produced from the scheme and the optimal Euclidean TSP.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.61
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• pp.33-39
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• 2000

In this paper, we present an algorithm for the multicast routing problem when there exit the cell replication limits of ATM switching nodes. This problem can be formulated as a Degree Constrained Minimum Steiner Tree Problem(DCSP). The proposed algorithm is a modification of the shortest path heuristic originally devised for minimum Steiner tree problem. From the experimental results, it can be seen that our algorithm is efficient to obtain a near optimal solution with comparatively low computational time.

• Journal of the military operations research society of Korea
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• v.26 no.1
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• pp.47-55
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• 2000

The purpose of this paper is to develop a new heuristic algorithm for vehicle routing problem. The algorithm is composed of two steps. First step is to make a initial solution using sweeping algorithm. Second step is to improve initial solution for optimal solution using node exchange algorithm and tabu search algorithm. We have proven that our algorithm has produced better results than solutions obtained by saving algorithm and genetic in ten example problems with different unit size.

• Journal of Internet Computing and Services
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• v.16 no.6
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• pp.47-55
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• 2015

The conventional dynamic routing methods in Software Defined Networks (SDN) set the optimal routing path based on the minimum link cost, and thereby transmits the incoming or outgoing flows to the terminal. However, in this case, flows can bypass the middlebox that is responsible for security service and thus, thus the network can face a threat. That is, while determining the best route for each flow, it is necessary to consider a dynamic service chaining, which routes a flow via a security middlebox. Therefore, int this paper, we propose a new dynamic routing method that considers the dynamic flow routing method combined with the security service functions over the SDN.