• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.275-275
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• 1996

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.282-285
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• 1998

The purpose of this study is to present a method for determining the k most vital arcs in the maximum flow problem using a heuristic method. Generally, the problem which determine the k most vital arcs in maximum flow problem has known as NP-hard. Therefore, in this study we propose a method for determining all the k most vital arcs in maximum flow problem using a genetic algorithm. The proposed algorithm found all alternatives within shorter time than other heuristic methods. The method presented in this study can determine all the alternatives when there exists other alternative solutions.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.4
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• pp.11-20
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• 1998

This paper deals with a mathematical model and an algorithm for the problem of determining k most vital arcs in the shortest path problem. First, we propose a 0-1 integer programming model for finding k most vital arcs in shortest path problem given the ordered set of paths with cardinality q. Next, we also propose an algorithm for finding k most vital arcs ln the shortest path problem which uses the 0-1 Integer programming model and shortest path algorithm and maximum flow algorithms repeatedly Malik et al. proposed a non-polynomial algorithm to solve the problem, but their algorithm was contradicted by Bar-Noy et al. with a counter example to the algorithm in 1995. But using our algorithm. the exact solution can be found differently from the algorithm of Malik et al.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.2
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• pp.47-58
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• 2001

The purpose of this study is to present methods for determining the k most vital arcs (k-MVAs) in shortest path problem (SPP) using evolutionary algorithms. The problem of finding the k-MVAs in SPP is to find a set of k arcs whose simultaneous removal from the network causes the greatest increase in the shortest distance between two specified nodes. Generally, the problem of determining the k-MVAs in SPP has been known as NP-hard. Therefore, to deal with problems of the real world, heuristic algorithms are needed. In this study we present three kinds of evolutionary algorithms for finding the k-MVAs in SPP, and then to evaluate the performance of proposed algorithms.

• Journal of the military operations research society of Korea
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• v.26 no.2
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• pp.120-130
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• 2000

The purpose of this study is to present a method for determining the k most vital arcs in shortest path problem using an evolutionary algorithm. The problem of finding the k most vital arcs in shortest path problem is to find a set of k arcs whose simultaneous removal from the network causes the greatest increase in the total length of shortest path. Generally, the problem determining the k most vital arcs in shortest path problem has known as NP-hard. Therefore, in order to deal with the problem of real world the heuristic algorithm is needed. In this study we propose to the method of finding the k most vital arcs in shortest path problem using an evolutionary algorithm which known as the most efficient algorithm among heuristics. The method presented in this study is developed using the library of the evolutionary algorithm framework and then the performance of algorithm is analyzed through the computer experiment.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.2
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• pp.184-191
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• 1999

The k most vital arcs (k-MVA) of a maximum flow problem is defined as those k arcs whose simultaneous removal from the network causes the greatest decrease in the throughput capability of the remaining system between a specified pair of nodes. In this study, we present a method for determining all the k-MVA in maximum flow problem using a minimal cardinality cut algorithm and k-th minimal cut ranking algorithm. For ranking cardinality cuts, we use Hamacher's ranking algorithm for cut capacity and by comparing present residual capacity of cardinality cut with expected residual capacity of next cardinality cut, we also present termination condition for this algorithm. While the previous methods cannot find all the alternatives for this problem, a method presented here has advantage of determining all the k-MVA.

• Journal of the military operations research society of Korea
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• v.25 no.2
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• pp.84-96
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• 1999

The purpose of this paper is to find the most vital arc in the minimum cost flow problem. The most vital arc is the arc whose removal results in the greatest influence in the costs or the amount of demands in a given minimum cost flow network. This problem can be well applied to the conflict situations such as military logistics network or communications network. In this situation, network user wants to know which arcs are the most vital to him so that he can reinforce these arcs against attack, while interdictor wants to destroy these arcs which increase the distance of the shortest path most through the network. When one of arcs is removed from the network of the minimum cost flow problem, two kinds of situations can be occurred ; breaking feasibility and increasing cost. In case of breaking feasibility, the rank of arcs are determined using the amount of modified flow in a related network which is made of modifying the optimal alternative of the minimum cost flow problem. The rank of arcs with the increased costs are determined by using a method which finds the directed cycle with the minimum cost in a related network.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.842-845
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• 2008

The protein interaction network contains a small number of highly connected protein, denoted hub and many destitutely connected proteins. Recently, several studies described that a hub protein is more likely to be essential than a non-hub protein. This phenomenon called as the centrality-lethality rule. This rule is widely credited to exhibit the importance of hub proteins in the complex network and the significance of network architecture as well. To confirm whether the rule is accurate, we investigated all protein interaction DBs of yeast in the public sites such as Uetz, Ito, MIPS, DIP, SGD, and BioGRID. Interestingly, the protein network shows that the rule is correct in lower scale DBs (e.g., Uetz, Ito, and DIP) but is not correct in higher scale DBs (e.g., SGD and BioGRID). We are now analyzing the features of networks obtained from the SGD and BioGRD and comparing those of network from the DIP.

• Childhood Kidney Diseases
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• v.18 no.1
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• pp.47-50
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• 2014

Infection is the most important cause of death in children with nephrotic syndrome. Influenza viral infections can be fatal for these children, given the annual outbreak of this virus, with the mortality rate being similar to that of respiratory syncytial virus in healthy children. Pneumonia is recognized as the most important complication of influenza infections, as it is associated with high death rates. However, the influenza vaccine, as well as antiviral agents, can be used for prevention and treatment. Therefore, aggressive management with influenza vaccination and antiviral agents will lower the overall mortality rate in children with nephrotic syndrome. Here we report the case of a 7-year-old boy with nephrotic syndrome and influenza A virus (H1N1) pneumonia.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.183-193
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• 2008

This paper shows the results of failure mode analysis and the system-level reliability model for the flight test of KSLV-I upper stage. First, the critical 14 functions of KSLV-I upper stage are identified and the mission profile of the flight test is analyzed. Then, based on the functional analysis and the mission profile analysis, we construct a hierarchical structure of failure modes and a system-level reliability model for the flight test of KSLV-I upper stage.