• Communications for Statistical Applications and Methods
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• 제27권5호
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• pp.569-578
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• 2020

Various graph clustering methods have been introduced to identify communities in social or biological networks. This paper studies the entropy-based and the Markov chain-based methods in clustering the undirected graph. We examine the performance of two clustering methods with conventional methods based on quality measures of clustering. For the real applications, we collect the mathematical subject classification (MSC) codes of research papers from published mathematical databases and construct the weighted code-to-document matrix for applying graph clustering methods. We pursue to group MSC codes into the same cluster if the corresponding MSC codes appear in many papers simultaneously. We compare the MSC clustering results based on the several assessment measures and conclude that the Markov chain-based method is suitable for clustering the MSC codes.

• 대한전자공학회논문지
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• 제21권6호
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• pp.94-104
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• 1984

하중 그래프(weighted graph)의 연결지수(connection index)라는 새로운 개념에 기초를 둔 회로망분할에 대한 0(v.e) -v, e는 각각 마디 및 가지의 수-의 새로운 효과적 휴리스딕(heuristic) 알고리즘을 제안하였다. 실험적 결과는 이 알고리즘이 매우 효과적이고 시험한 다수의 분할문제에 대하여 최적의 또는 거의 최적의 해를 준다는 것을 실증하고 있다. 제안된 알고리즘의 몇 가지 응용을 제안하였고 그 컴퓨터 프로그램을 상세히 기술하였다.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제10권4호
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• pp.93-100
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• 2021

블록체인의 확장성 문제를 해결하기 위한 이더리움 샤드 시스템은 부하 균형 문제가 존재하며 이는 그래프 분할 문제로 모델링된다. 본 논문에서는 게임 이론의 협상 해법을 사용하여 이더리움 샤드 시스템의 상반된 효용에 대한 협상이 가능한 적응적 온라인 가중그래프 분할 알고리즘을 제안한다. 게임 이론의 협상 해법은 상반된 효용의 협상점을 공정하게 결정할 수 있는 공리적 해법이다. 제안 알고리즘은 기존 온라인 그래프 분할 알고리즘을 가중그래프에 적용할 수 있도록 개선하였으며 대표적인 교섭 해법인 내쉬 협상 해법을 확장한 확장 내쉬 협상 해법을 사용하여 이더리움 시스템 상황을 고려한 설계를 통해 효과적으로 부하 균형을 수행하였다. 실험 결과, 대표적인 온라인, 오프라인 그래프 분할 알고리즘에 비해 최대 37% 우수한 성능을 보였다.

• 한국통신학회논문지
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• 제40권12호
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• pp.2410-2418
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• 2015

In this paper, we consider the femto users and their mutual interference as graph elements, nodes and weighted edges, respectively. The total bandwidth is divided into a number of resource blocks (RBs) and these are assigned to the femto user equipment (FUEs) using a graph coloring algorithm. In addition, resources blocks are assigned to the femto users to avoid inter-cell interference. The proposed scheme is compared with the traditional scheduling schemes in terms of throughput and fairness and performance improvement is achieved by exploiting the graph coloring scheme.

• 전자공학회논문지A
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• 제31A권1호
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• pp.84-92
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• 1994

In this paper, we present a novel scheduling algorithm using the weighted interval graph. An interval graph is constructed, where an interval is a time frame of each operation. And for each operation type, we look for the maximum clique of the interval graph: the number of nodes of the maximum clique represents the number of operation that are executed concurrently. In order to minimize resource cost. we select the operation type to reduce the number of nodes of a maximum clique. For the selected operation type, an operation selected by selection rule is moved to decrease the number of nodes of a maximum clique. A selected operation among unscheduled operations is moved repeatly and assigned to a control step consequently. The proposed algorithm is applied to the pipeline and the nonpipeline data path synthesis. The experiment for examples shows the efficiency of the proposed scheduling algorithm.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2008년도 추계학술대회 및 정기총회
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• pp.430-434
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• 2008

The group Steiner tree problem is a generalization of the Steiner tree problem that is defined as follows. Given a weighted graph with a family of subsets of nodes, called groups, the problem is to find a minimum weighted tree that contains at least one node in each group. We present some existing and some new formulations for the problem and compare the relaxations of such formulations.

• 대한산업공학회지
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• 제37권3호
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• pp.191-197
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• 2011

The group Steiner tree problem is a generalization of the Steiner tree problem that is defined as follows. Given a weighted graph with a family of subsets of nodes, called groups, the problem is to find a minimum weighted tree that contains at least one node in each group. We present some existing and some new formulations for the problem and compare the relaxations of such formulations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권2호
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• pp.540-557
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• 2021

Privacy vulnerability of social networks is one of the major concerns for social science research and business analysis. Most existing studies which mainly focus on un-weighted network graph, have designed various privacy models similar to k-anonymity to prevent data disclosure of vertex attributes or relationships, but they may be suffered from serious problems of huge information loss and significant modification of key properties of the network structure. Furthermore, there still lacks further considerations of privacy protection for important sensitive edges in weighted social networks. To address this problem, this paper proposes a privacy preserving method to protect sensitive weighted edges. Firstly, the sensitive edges are differentiated from weighted edges according to the edge betweenness centrality, which evaluates the importance of entities in social network. Then, the perturbation operations are used to preserve the privacy of weighted social network by adding some pseudo-edges or modifying specific edge weights, so that the bottleneck problem of information flow can be well resolved in key area of the social network. Experimental results show that the proposed method can not only effectively preserve the sensitive edges with lower computation cost, but also maintain the stability of the network structures. Further, the capability of defending against malicious attacks to important sensitive edges has been greatly improved.

• 한국군사과학기술학회지
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• 제18권4호
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• pp.441-450
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• 2015

The tactical communications network has to be deployed rapidly at military operation area and support the communications between the military command systems and the weapon systems. For that, the frequency assignment is required for backbone wireless links of tactical communications network without frequency interferences. In this paper, we propose a frequency assignment method using net filter discrimination (NFD) and graph coloring to avoid frequency interferences. The proposed method presents frequency assignment problem of tactical communications network as vertex graph coloring problem of a weighted graph. And it makes frequency assignment sequences and assigns center frequencies to communication links according to the priority of communication links and graph coloring. The evaluation shows that this method can assign center frequencies to backbone communication links without frequency interferences. It also shows that the method can improve the frequency utilization in comparison with HTZ-warfare that is currently used by Korean Army.

• 한국인터넷방송통신학회논문지
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• 제13권1호
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• pp.143-152
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• 2013

주어진 그래프 G=(V,E), n=|V|, m=|E|에 대해 최소절단을 찾는 연구는 공급처 s와 수요처 t가 주어지지 않은 경우와 주어진 경우로 구분된다. s와 t가 주어지지 않은 무방향 가중 그래프에 대한 Stoer-Wagner 알고리즘은 임의의 정점을 고정시키고 최대 인접 순서로 나열하여 마지막 정점의 절단 값과 마지막 2개 정점을 병합하면서 정점을 축소시키는 방법으로 $\frac{n(n-1)}{2}$회를 수행한다. 또한, s와 t가 주어진 그래프에 대한 Ford-Fulkerson 알고리즘은 증대경로를 탐색하여 절단 간선을 결정한다. 더 이상의 증대 경로가 없으면 절단 간선들의 조합으로 최소절단을 결정해야 한다. 본 논문은 단일 s와 t가 주어진 무방향 가중 그래프에 대해 최대인접 병합과 절단값을 동시에 계산하는 방법으로 n-1회 수행으로 단축시켰다. 또한, Stoer-Wagner 알고리즘은 최소 절단을 기준으로 V=S+T로 양분하지 못할 수 있는데 반해 제안된 알고리즘은 정확히 양분시켰다. 제안된 알고리즘은 Ford-Fulkerson의 증대경로를 찾는 수행횟수보다 많이 수행하지만 수행과정에서 최소절단을 결정하는 장점이 있다.