• 대한산업공학회지
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• 제35권1호
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• pp.87-91
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• 2009

In the server disconnection problem, a network with m servers and their users is given and an attacker is to destroy a set of edges to maximize his net gain defined as the total disconnected utilities of the users minus the total edge-destruction cost. The problem is known to be NP-hard. In this paper, we study the server disconnection problem restricted to a ring network. We present an efficient combinatorial algorithm that generates an optimal solution in polynomial time.

• Management Science and Financial Engineering
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• 제11권1호
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• pp.49-61
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• 2005

We consider the graph disconnection problem, which is to find a set of edges such that the total cost of destroying the edges is no more than a given budget and the weight of nodes disconnected from a designated source by destroying the edges is maximized. The problem is known to be NP-hard. We present an integer programming formulation for the problem and develop an algorithm that includes a preprocessing procedure for reducing the problem size, a heuristic for providing a lower bound, and a cutting plane algorithm for obtaining an upper bound. Computational results for evaluating the performance of the proposed algorithm are also presented.

• 한국경영과학회지
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• 제29권1호
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• pp.113-125
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• 2004

The network disconnection problem ms to find a set of edges such that the total cost of removing the edges is no more than a given budget and the weight of nodes disconnected from a designated source by removing edges is maximized. Martel et at. have shown that the problem with unit capacity and unit demand Is NP-hard and Myung and kim present an integer programming formulation and develop an algorithm that Includes a preprocessing procedure and lower and upper bounding strateagies. in this paper, we present new findings on the properties of the optimal solution and an alternative integer programming formulation, based on which new lower and upper bounding strategies are developed. Computational results for evaluating the performance of the proposed algorithm are also presented.

• 한국융합학회논문지
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• 제8권8호
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• pp.77-82
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• 2017

디스플레이 제조 공정에서는 패널의 이송 목적으로 컨베이어 시스템이 널리 사용된다. 이 컨베이어에는 정전기로 인한 제품 불량을 예방하기 위해 접지선이 다수 사용되는데, 이송 롤러의 회전 운동이나 말림 등의 원인으로 접지선이 단선되어 제품 불량으로 이어지는 경우가 빈번히 발생된다. 이런 문제 해결을 위해 접지선의 단선을 실시간으로 검출 가능한 시스템의 필요성이 커지고 있다. 따라서 본 논문에서는 컨베이어 구동부와 패널의 마찰로 발생되는 ESD(Electro-Static Discharge) 접지선의 단선 모니터링 시스템을 제안한다. 제안 시스템은 ATmega 2560 및 휘트스톤 브릿지(Wheatstone Bridge) 회로를 이용해 접지선의 단선 및 탈조 검출이 가능한 모니터링 시스템으로써, 접지선의 단선을 즉시 검출해 조치할 수 있으므로, 정전기로 인한 제품의 불량률을 줄일 수 있다. 본 논문에서 제안한 시스템은 접지선이 사용되는 산업의 생산 및 시험 장비에 적용 가능할 것으로 기대된다.

• 디지털콘텐츠학회 논문지
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• 제9권4호
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• pp.533-541
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• 2008

분산 모바일 시스템에서 혼잡제어와 끊김 문제 해결은 주요한 관심사로 떠오르고 있다. 본 논문에서는 분산 모바일 트랜잭션을 지원하는 시스템의 성능 개선을 위해 그룹화 기반의 퍼지 참조 스트리밍 기법을 이용한다. 이 기법은 모바일 클라이언트에서 제기된 트랜잭션 요청문제를 GS인터페이스를 이용하여 해결하도록 한다. 그리고 끊김 문제를 해결하기 위해 트랜잭션 읽기/갱신기법을 이용하여 스트리밍 서비스를 효율적으로 수행하도록 한다. 실험 평가 결과 제안된 기법이 다른 기법보다 효율적임을 보인다.

• 한국경영과학회지
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• 제28권4호
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• pp.131-143
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• 2003

In this paper, we present a survey about the various graph partition problems including the clustering problem, the k-cut problem, the multiterminal cut problem, the multicut problem, the sparsest cut problem, the network attack problem, the network disconnection problem. We compare those problems focusing on the problem characteristics such as the objective function and the conditions that the partitioned clusters should satisfy. We also introduce the mathematical programming formulations, and the solution approaches developed for the problems.

• 가정과삶의질연구
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• 제29권4호
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• pp.175-186
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• 2011

The purpose of this study was to explore the differences in interactive peer play according to the type of problem behavior. The subjects were 112(67 boys, 45 girls) S-year-old children at 25 daycare centers in Seoul, Gyeonggi, and Gyeongsang areas. Instruments included the Preschool Behavior Questionnaire(PBQ; Behar & Stringfield, 1974) and the Penn Interactive Peer Play Scale(PIPPS) in both the teacher version(Choi & Shin, 2008) and the parent version(Fantuzzo, Mendez, & Tighe, 1998). The data were analyzed with descriptive statistics, cluster analysis, t-test, and one-way ANOVA using the SPSS 18.0 software program. The results showed that the clusters of problem behaviors on the PBQ could be grouped into four categories; 'hostility-aggressiveness', 'hyperactivity- distractibility', 'anxiety-fear', and 'combined'. In addition, group differences among the problem behaviors were significantly found in 'play disruption' and 'play disconnection' but not in 'play interaction' of the PIPPS on teachers' and parents' ratings. Specifically, group differences were not found in the parental reports, while significant group differences were noted in the 'play disconnection on PIPPS component of the teachers' reports.

• 전기학회논문지
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• 제64권10호
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• pp.1448-1453
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• 2015

In this paper, we propose an alternative method of communication to improve the reliability of in-vehicle networks by jointly using wireless communication networks. Wired Communication networks have been used in vehicles for the monitoring and the control of vehicle motion, however, the disconnection of wires or hardware fault of networks may cause a critical problem in vehicles. If the network manager detects a disconnection or faults in wired in-vehicle network like the Controller Area Network(CAN), it can redirect the communication path from the wired to the wireless communication like the Zigbee network. To show the validity and the effectiveness of the proposed in-vehicle network architecture, we implement the Electronic Stability Control(ESC) system as ECU-In-the-Loop Simulation(EILS) and verify that the control performance can be kept well even if some hardware faults like disconnection of wires occur.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2006년도 춘계공동학술대회 논문집
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• pp.1034-1035
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• 2006

본 논문에서는 기존의 노드 단절 문제와 관련이 있는 k-서버 단절 문제를 정의하고, 계산 복잡도 및 근사해성에 대해 규명하였다. k-서버 단절 문제는 비근사성(inapproximaton)을 갖으며, 우리는 k가 고정됐을 때 0.5-근사해법을 갖는다는 것을 보였다.

• 한국멀티미디어학회논문지
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• 제20권9호
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• pp.1527-1540
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• 2017

Recently, due to the rapid development of the internet, the production and demand of high capacity contents are rapidly increasing. In order to accommodate the changing trend of internet usage, researches on CCN, the future internet architecture, are actively being conducted. Mobility support is an important challenge in CCN real-time services, given that today's internet environment is changing to mobile and real-time services are increasing. In CCN real-time services, the mobility problem can be largely divided into consumer mobility, provider mobility, and intermediate-node mobility. Among them, when the intermediate-node moves in the CCN real-time services, the service disconnection occurs and the QoS degradation is caused. In this paper. we propose Intermediate-Node Mobility Support(INMS) to support the intermediate-node mobility in CCN real-time services. Experimental results show that the proposed scheme shows better performance than CCN in terms of service disconnection time and packet loss.