• Journal of the Institute of Convergence Signal Processing
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• v.3 no.2
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• pp.89-95
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• 2002

Global routing is to assign each net to routing regions to accomplish the required interconnections. The most popular algorithms for global routing inlcude maze routing algorithm, line-probe algorithm, shortest path based algorithm, and Steiner tree based algorithm. In this paper we propose weighted network heuristic(WNH) as a minimal Steiner tree search method in a routing graph and a genetic algorithm based on WNH for the global routing. We compare the genetic algorithm(GA) with simulated annealing(SA) by analyzing the results of each implementation.

• Journal of Internet Computing and Services
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• v.10 no.5
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• pp.1-12
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• 2009

A routing policy based on BGP community routing permits to select a specific route for particular network by making use of user-defined routing policies. Especially, community based routing policy is recently getting a great concern to enhance overall performance in the global research networks which are generally inter-connected large number of different characterized networks. In this paper, we analyze the community routing which has been applied in existing global research networks in the network performance point of view, and catch hold of problems caused by the routing performance in a new global research network. Then, we suggest an effective community routing policy model along with an interconnection architecture of research networks, in order to make correct some wrong routings and resolve an asymmetric routing problem, for a new global research network. Our work is expected to be utilized as an enabling base technology to improve the network performance of future global research networks as well as commercial networks.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.3
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• pp.60-67
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• 1985

A new glut bel routing technique for gate array is described in this paper. In former global routers the position of pins is considered to be in the center of the cell. So it is impossible to exactly estimate the number of signal lines passing through each channel. As a result, an overflow occurs and the overflow violates 100% wiring in detailed routing pro-cesses. Besides this, there are some problems in former global routers, for example, design time and cost, etc. This paper proposed a new algorithm in which pins ordering is considered to solve these problems. Using this algorithm, a global router is developed. Program experiments show the efficiency of the proposed algorithm.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.356-367
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• 2007

In large networks, maintaining precise global network state information is impossible. The imprecise network state information has significant impacts on Quality-of-Service(QoS) routing and path establishment. In this paper, we develop analytical models for investigating the QoS routing schemes that are designed to tolerate imprecise network state information, and study the performance of various QoS routing schemes, including randomized routing, multi-path routing, and probability based routing, using both the models and simulations. We further propose a new mechanism, called local rerouting, that improves the effectiveness of QoS path establishment in the presence of imprecise global network state information. Local rerouting is orthogonal to existing schemes for dealing with imprecise state information and can be used in conjunction with them to alleviate the impacts of the imprecise information. The results of our performance study indicate that local rerouting is robust and effective.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.10
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• pp.49-56
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• 1992

A new global routing algorithm which dynamically adjusts its cost parameters depending on the given routing poroblem to find a near optimum solution has been developed. The proposed algorithm efficiently performs global routing on general area in which all the pin positions are given. This algorithm is composed of two phases`In the first phase, it routes each net by searching a minimum cost path while ignoring the channel capacity. In the second iterative phase, it rips up nets which pass the channel at which the horizontal or vertical routing density exceeds the capacity and then it reroutes them using a modified set of cost parameters. Applying the above phases, paths for nets are found such that routing density doesn't exceed the capacity in each channel and that nets are routed with minimum cost. Experimental results for several benchmark examples including difficult-4, difficult-8, difficult-16, Primary1 and Primary2 show that our method generates better results than other published ones.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2002.06a
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• pp.53-53
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• 2002

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.4
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• pp.431-435
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• 2008

Since previous work CDP(Congestion Driven Placement) [1] considers all possible directions to move every cell in nets which contribute highly to routing congestion, it consumes CPU time a lot. In this paper, we propose a faster global placement technique, so called ICDGP(Improved Congestion Driven Global Placement) to relieve the routing congestion. ICDGP uses the force-directed method to determine the target locations of the cells in the nets in the congested spots, and considers only to move the target location for each cell. If moving multiple cells simultaneously is considered better than moving each cell one by one it moves multiple cells simultaneously. By experimental results, ICDGP produces less congested placement than CDP does. Particularly, the CPU time is reduced by 36% on average.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.2
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• pp.110-118
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• 2015

Weather routing method is one of the best practices of SEEMP (Ship Energy Efficiency Management Plan) for fuel-efficient operation of ship. KR is carrying out a basic research for development of the weather routing algorithm and making a monitoring system by FOC (Fuel Oil Consumption) analysis compared to the reference, which is the great circle route. The added resistances applied global sea/weather data can be calculated using ship data, and the results can be corrected to ship motions. The global sea/weather data such as significant wave height, ocean current and wind data can be used to calculate the added resistances. The reference route in a usual navigation is the great circle route, which is the shortest distance route. The global sea/weather data can be divided into grids, and the nearest grid data from a ship's position can be used to apply a ocean going vessel's sea conditions. Powell method is used as an optimized routing technique to minimize FOC considered sea/weather conditions, and FOC result can be compared with the great circle route result.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.10
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• pp.8-18
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• 1997

In FPGAs, we may use the property of the routing architecture for their routing compared to the routing in the conventional layout style. Especially, the Xilinx XC4000 series FPGAs have very special routing architecture in which the routing problem is equivalent to the two dimensional track assignment problem. In this paper, we propose a new FPgA detailed routing method by developing a two dimensional trackassigment heuristic algorithm. The proposed routing mehtod accept a global routing result as an input and obtain a detailed routing such that the number of necessary wire segments in each connection block is minimized. For all benchmark circuits tested, our routing methd complete routing results. The number of used tracks are also similar to the results by thedirect routing methods.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.2
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• pp.130-139
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• 1995

A hierarchical placement system based on routing region assignment has been developed to increase the probability of routing completion after placement. While most of the existing placement systems attempt to reduce the cell density at the portions where routing density is high, our method is distinguished in that specific routing regions are allocated to secure complete routing where the routing density is greater than the routing capacity. Hierarchy is vuilt by clustering and recursive paritioning, and the initial placement obtained by partitioning at each level is improved by using the region refinement algorithm. After placement at each hierarchical level, global routing is performed and fouting regions are assigned, if routing density is greater than routing capacity, to be considered at the next level of placement. the proposed algorithm has been implemented and applied to place several industrical gate-array circuits. A couple of circuits which cannot be routed by using conventional placement techniques can be completely routed by using our new placement technique with routing region assignment.