• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.41-46
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• 2011

Mobile Ad-Hoc networks (MANET) has been getting the spotlight in the area of the wireless networks because of its flexibility and salability, and developing of many applications with it. As a consequence, MANETs are required to process not only simple data traffics, but also multimedia traffics, which has some constraints on the performances. However, unlike wired-networks, the wireless networks have frequent route-disconnections due to some reasons such as channel errors and mobility. Such frequent link disconnections makes the delivery of multimedia traffics difficult. Even though there many researches on multimedia transmissions on various environments, the performances of multimedia transmissions over fading channel and mobility even using various routing protocols have not been evaluated. Therefore, this paper extensively simulates the MPEG-4 video transmission over fading channel environment with node's mobility. In addition, the performances with two routing protocols such as AODV and DSR are compared. Finally, the simulation results shows that DSR protocol has the better performances to deliver MPEG-4 traffic.

• Journal of Wetlands Research
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• v.18 no.2
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• pp.148-153
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• 2016

Hydraulic and hydrological flood routing methods are commonly used to analyze temporal and spatial flood influences of flood wave through a river reach. Hydrological flood routing method has relatively more simple and reasonable performance accuracy compared to the hydraulic method. Storage constant used in Muskingum method widely applied in hydrological flood routing is very similar to the travel time. Focusing on this point, in this study, we estimate the travel time from HEC-RAS results to estimate storage constant, and develop a non-linear regression equation for the travel time using reach length, channel slope, and discharge. The estimated flow by Muskingum model with storage constant of nonlinear equation is compared with the flow calculated by applying the HEC-RAS 1-D unsteady flow simulation. In addition, this study examines the effect on the weighting factor changes and interval reach divisions; peak discharge increases with the bigger weighting factor, and RMSE decreases with the fragmented division.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.5
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• pp.145-151
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• 1989

A new preprocess technique is presented which can improve the routing efficiency in the gate array layout designs. In order to resolve the cycle problem in the detailed routing, we exchange the logically equivalent pins in each channel. The signal nets are divided, and doubly connected signal net components are removed, so that the increase in the number of tracks can be controlled.

• The Transactions of the Korea Information Processing Society
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• v.4 no.11
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• pp.2732-2744
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• 1997

This paper is based on multicasting model in k-ary n-cubes, and Proposes an adaptive wormhole routing algorithm which allows faults and channel contention. The proposed algorithm only requires $2{\times}n$ virtual channels per physical channel which is proportional to the dimension n in order to allow (n-1) faults in a k-ary n-cube. This method uses smaller number of virtual channels than the previously Proposed adaptive routing algorithms [5, 18]. Through a chaos simulator, we have measured message delay considering fault-tolerant as well as message traffic to our adaptive routing algorithm.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.4
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• pp.81-86
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• 2003

Current growth of VLSI design depends critically on the research and development of automatic layout tool. Automatic layout is composed of placement assigning a specific shape to a block and arranging the block on the layout surface and routing finding the interconnection of all the nets. Algorithms performing placement and routing impact on performance and area of VLSI design. Switchbox routing is a problem interconnecting each terminals on all four sides of the region, unlike channel routing. In this paper we propose a genetic algorithm searching solution space for switchbox routing problem. We compare the performance of proposed genetic algorithm(GA) for switchbox routing with that of other switchbox routing algorithm by analyzing the results of each implementation. Consequently experimental results show that out proposed algorithm reduce routing length and number of the via over the other switchbox routing algorithms.

• ETRI Journal
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• v.40 no.5
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• pp.613-623
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• 2018

The instability of operational channels on cognitive radio networks (CRNs), which is due to the stochastic behavior of primary users (PUs), has increased the complexity of the design of the optimal routing criterion (ORC) in CRNs. The exploitation of available opportunities in CRNs, such as the channel diversity, as well as alternative routes provided by the intermediate nodes belonging to routes (internal backup routes) in the route-cost (or weight) determination, complicate the ORC design. In this paper, to cover the channel diversity, the CRN is modeled as a multigraph in which the weight of each edge is determined according to the behavior of PU senders and the protection of PU receivers. Then, an ORC for CRNs, which is referred to as the stability probability of communication between the source node and the destination node (SPC_SD), is proposed. SPC_SD, which is based on the obtained model, internal backup routes, and probability theory, calculates the precise probability of communication stability between the source and destination. The performance evaluation is conducted using simulations, and the results show that the end-to-end performance improved significantly.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.702-704
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• 2010

Wireless LAN(Local Area Network) environment to support QoS in IEEE802.11 Working Group has standardized on the IEEE 802.11e. IEEE 802.11e EDCA channel access of the high priority traffic as by raising the probability of a chance to support QoS. This is a high priority traffic than low priority traffic, channel access is not necessarily the first. Therefore, as all traffic channels, if you have the same routing path, lower priority traffic on the performance of high priority traffic, sustainable impact. As a result, EDCA, such as voice or video to guarantee QoS for multimedia applications, follow the crowd. In this paper, to solve these problems by using Multi-Interface Multi-Path Routing Algorithm is proposed. Interface for each use in IEEE 802.11e EDCA Access Category much differently by each of the Routing Path for high priority traffic and guarantee QoS.

• Journal of Korea Multimedia Society
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• v.2 no.2
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• pp.184-194
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• 1999

We present a new algorithm to minimize channel contention while sending multiple messages from multiple source to overlapped destination set on Multistage Interconnection Network (MIN) which supports wormhole routed turnaround routing. The multicast tree of the U-MIN(Unicast MIN) algorithm is useful in performing messages from one source to multiple destination but gives rise to a serious channel connection in performing multiple multicast because it has been designed for only single multicast. For multiple multicast communication on MIN, we address how to implement multiple multicast services efficiently. And a SPU-MIN(Source Partitioned Unicast MIN) algorithm is proposed and shown to be superior than the U-MIN algorithm for multiple multicast. The turnaround routing algorithm based on wormhole routing technique is employed as a message sending method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.4
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• pp.72-77
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• 1984

A placement program in LSI layout is developed and the results of test are discussed in this paper. In order to achieve 100% wiring, this paper introduces, as a virtual routing method, an algorithm which is close to the real routing. This algorithm is reflected to calculate the channel density. An object function is introduced to achieve minimization of total wire length, number of cuts, and maximum channel density simultaneously. The time complexity for the proposed virtual routing algorithm is O(n2). The time required for the algorithm is very short. This algorithm represents the routing state which is close to minimum wire length. So this algorithm is very proper to the application of placement problem. An auto-placement program is developed by the use of this algorithm. The efficiency of the proposed algorithm is shown in the test of the developed program.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11B
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• pp.981-988
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• 2008

In this paper, the efficient AODV routing algorithm in MANET is proposed. Because transmission channel has a high error rate and loss in MANET, the number of hops can't be regarded as an absolute network metric. After measuring FER periodically at the data link layer using cross-layer design, the scheme that every node forwards the weight of link status in the reserved field of AODV protocol is used. In order to find the efficient route, we design AODV to be able to select an optimal route that has a good channel status by evaluating the sum of weight. The proposed AODV improves throughput, routing overhead and average end-to-end delay in comparison with the generic AODV.