• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.51
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• pp.29-40
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• 1999

The distribution center location and routing problem involves interdependent decisions among facility, transportation, and inventory decisions. The design of distribution system affects the customers' purchase decision by sets the level of customer service to be offered. Thus the lower product availability may cause a loss of demand as falls off the customers' purchase intention, and this is related to the firm's profit reduction. This study considers the product availability of the distribution centers as the measure of the demand level change of the demand points, and represents relation between customer service and demand level with linear demand function. And this study represents the distribution center location and routing to demand point in order to maximize the total profit that considers the products' sales revenue by customer service, the production cost and the distribution system related costs.

• Journal of the Korea Society for Simulation
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• v.15 no.3
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• pp.79-86
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• 2006

This paper proposes a new protocol to enhance the routing performance and applies our proposal to AODV (Ad hoc On-demand Distance Vector routing) protocol, which is a typical on-demand routing protocol in MANET. In general, when a route repair procedure is performed due to the transfer or failure of a node, the source node re-initiate a route discovery procedure in most routing protocols of MANET. This causes to increase the control traffic overhead largely and degrade the routing performance. The main idea of our study is to provide a methodology that can minimize the control traffic overhead and enhance the performance by initiating a route repair procedure at destination node and utilizing the previous routing information maximumly. To evaluate the performance of the our mechanism, we have performed a series of simulations. The simulations include comparisons with AODV and AODV with local repair. The simulations have been executed under simulation environments taking into account mobility speed and network site. The simulation results show that our proposal overall outperforms the existing protocols.

• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.191-198
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• 2007

A mobile ad-hoc network (MANET) is an autonomous, infrastructure-less system that consists of mobile nodes. In MANET, on demand routing protocols are usually used because network topology changes frequently. AODV, which is a representative on demand routing protocol, operates using the routing table of each node that includes next hop of a route for forwarding packets. It maintains the established route if there is not an expiration of route or any link break. In the paper, we propose a partially adaptive route maintenance scheme (AODV-PA) based on AODV, which provides dynamic route modification of initial route for selecting the effective route using not only next hop but also next-hop of next-hop (i.e. 2-hop next node) acquired through route discovery process. In addition, the proposed scheme additionally manages the routing table for preventing exceptional link breaks by route modification using HELLO messages. We use NS 2 for the computer simulation and validate that the proposed scheme is better than general AODV in terms of packet delivery ratio, latency, routing overhead.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1997.10a
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• pp.201-204
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• 1997

This study is focussed on optimization problems which require allocating the restricted inventory to demand points and assignment of vehicles to routes in order to deliver goods for demand sites with optimal decision. This study investigated an integrated model using three step-by-step approach based on relationship that exists between the inventory allocation and vehicle routing with restricted amount of inventory and transportations. we developed several sub-models such as; first, an inventory-allocation model, second a vehicle-routing model based on clustering and a heuristic algorithms, and last a vehicle routing scheduling model, a TSP-solver, based on genetic algorithm. Also, for each sub-models we have developed computer programs and by a sample run it was known that the proposed model to be a very acceptable model for the inventory-allocation and vehicle routing problems.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.3
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• pp.317-324
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• 2016

WiMedia provides the data rate of up to 1Gbps, but the transmission range is restricted to approximately 10 meters. When constructing a multi-hop WiMedia network to extend its coverage, conventional hop-based routing may not guarantee satisfactorily the required QoS. We propose two QoS routing techniques for the WiMedia-based wireless mesh network. The proopsed QoS routing reflects the characteristics of TDMA-based WiMedia MAC and develops QoS extensions separately for on-demand routing and table-driven routing. Through simulations, we identify that the QoS routing shows better performance than the hop-based routing. It also turns out that the QoS on-demand routing and the QoS table-driven routing show conflicting performance results depending on the transmission power.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1092-1099
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• 2017

In this paper, we propose a novel geographical on-demand routing protocol for a mobile ad-hoc network (MANET) that resolves the broadcast storm problem of ad-hoc on-demand distance vector (AODV) routing protocol. The candidates relaying route request (RREQ) packet are geographically restricted by the locations of the destination and a (RREQ sender. Then, the duplicate RREQs, which are generally discarded in the protocols that follow the principle of the AODV, are parsed to avoid redundant RREQ rebroadcasts and to perform passive acknowledgement with respect to a RREQ rebroadcast. The proposed routing protocol is implemented by modifying the source code of the AODV in QualNet. It is shown through QualNet simulations that the proposed routing protocol significantly improves the packet delivery ratio and the latency of the AODV in high-density and heavy traffic network scenarios.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.121-124
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• 2001

Dynamic Source Route(DSR) protocol is a simple and efficient routing protocol designed specially for use of the multi-hop Ad Hoc Network. DSR allows the network to be completely self-organized and self-configured without the need for any existing infrastructure or administration. DSR protocol consists of the two mechanisms of Router discovery and Router Maintenance, works entirely On-demand in all aspects. In this paper, we will present the performance of DSR protocol on the multi-hop wireless Ad Hoc Networks, illustrate it with simulation, and then analysis the algorism of DSR.

• Journal of Korea Multimedia Society
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• v.9 no.5
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• pp.606-614
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• 2006

The conventional on-demand mobile ad hoc routing algorithms (DSR and AODV) initiate route discovery only after a path breaks, incurring a significant cost and time in detecting the disconnection and establishing a new route. In this theory, we investigate adding proposed pro-active route selection and maintenance to the conventional on-demand mobile ad hoc routing algorithms(DSR and AODV). The key idea is to be only considered likely to be a path break when the received packet power becomes close to the minimum critical power and to be generated the forewarning packet when the signal power of a received packet drops below a optimal threshold value. After generated the forewarning packet, the source node can initiate rout discovery in advance; potentially avoiding the disconnection altogether. Our extensive simulation study shows that the proposed advance-active route selection and maintenance algorithms outperforms the conventional on-demand routing protocol based on DSR and AODV in terms of packet delivery ratio, packet latency and overhead.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.400-402
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• 2003

Ad­hoc Network는 Mobile Node들 간에 Multi­hop 무선 링크로 구성되는 Network을 일컫는 말이며, 동시에 Network를 통제하는 Infrastructure없이 Node들 간의 상호 통신에 의해서 Network이 구성되기도 하고, Node들이 이동하거나 환경적인 장애에 의해서 일시적으로 Network이 구성되지 않기도 한다. 이 논문에서는 대표적인 On­demand Routing Algorithm인 DSR를 이용하여, 두 개의 경로를 유지하여 Primary Path에 문제가 발생하는 경우, Secondary Path가 Primary Path로 전환되어 Data를 전송하고, 이 전 Primary Path에 대하여 지역적으로 복구(Repair)를 수행하고, 설정된 Secondary Path에 대해서도 특정한 조건에서 복구작업을 수행함으로써 Ad­hoc Network에서 경로를 찾고 설정하는데 필요한 Routing Overhead를 줄이고 Ad­hoc Network의 특성상 반드시 보완하여야 하는 전송 Route에 대한 Robustness를 강화하는 방법이다.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.7
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• pp.495-499
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• 2009

An underlying assumption in geographic routing protocols, periodic position exchange among neighbors has two problems: (1) unnecessary energy consumptions of nodes in regions without data delivery and (2) position invalidation of neighbors in forwarding data. Hence, this paper proposes an on-demand geographic routing protocol in mobile wireless sensor networks. The proposed protocol make a sender acquire position information of only necessary neighbors to reduce energy consumption in data forwarding time and determine an optimal node among them as a receiver for relaying data to a destination by considering their mobility. Simulation results show that the proposed protocol is more efficient than an existing geographic routing protocol.