• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1442-1445
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• 2010

오늘날 통신기술의 급속한 발달에 따라 자동화 및 무인화 서비스를 제공하는 지능형 선박에 대한 연구, 개발이 활발이 진행 되고 있다. 이에 선박 내 각 장비들의 기능이 고도화 됨으로써, 선박네트워크 환경에서 이들 장비를 효율적으로 제어할 수 있는 연구가 필요한 실정이다. 지능형 선박의 백본 네트워크는 네트워크 구축 환경의 제약과 자동화 및 무인화 특징을 가진다는 점에서, 선박의 사고로 인한 네트워크의 결손이 큰 재해를 가져올 수 있으므로 고수준의 생존성이 요구된다. 따라서 본 논문에서는 고생존 선박 통신망을 고려하여 네트워크 통신 장비들이 이중화 경로를 통해 서로 연결된 이중화 네트워크 토폴로지를 최소의 비용으로 설계하였다. 설계한 이중화 네트워크 토폴로지를 이론적 분석 및 ILP(Integer Linear Programming)를 통해 실험한 결과, 네트워크 생존성에 우수한 성능을 나타내는 것을 확인할 수 있었다.

• Journal of KIISE:Information Networking
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• v.34 no.5
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• pp.360-369
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• 2007

Since wireless sensor networks consist of nodes with the constrained battery, it is important to construct the topology performing energy-efficient routing while maximizing the whole network lifetime. Previous works related to this do not take into consideration the specific communication pattern in wireless sensor networks. In this paper, we propose a novel routing algorithm, called Up-Down Tree(UDT), which first constructs the tree topology based on distance and then adjusts the transmission range determined by the two different phases, tree setup and data gathering, to adapt the specific communication pattern in wireless sensor networks. Therefore, the UDT can improve energy efficiency, maximize the network lifetime, and block network partition Simulation results show that the UDT has the improved energy efficiency by constructing the optimal topology.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.905-916
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• 2004

Self-organizing hierarchical ad hoc network (SOHAN) is a new ad-hoc network architecture designed to improve the scalability properties of conventional 'flat' ad hoc networks. This network architecture consists of three tiers of ad-hoc nodes, i.e.. access points, forwarding nodes and mobile nodes. This paper presents a topology discovery and routing protocol for the self-organization of SOHAN. We propose a cross-layer path metric based on link quality and MAC delay which plays a key role in producing an optimal cluster-based hierarchical topology with high throughput capacity. The topology discovery protocol provides the basis for routing which takes place in layer 2.5 using MAC addresses. The routing protocol is based on AODV with appropriate modifications to take advantage of the hierarchical topology and interact with the discovery protocol. Simulation results are presented which show the improved performance as well as scalability properties of SOHAN in terms of through-put capacity, end-to-end delay, packet delivery ratio and control overhead.

• Journal of KIISE:Software and Applications
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• v.32 no.10
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• pp.963-973
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• 2005

Increasing attention is being recently devoted to various problems inherent in the topological design of networks systems. The topological structure of these networks can be based on service centers, terminals (users), and connection cable. Lately, these network systems are well designed with tiber optic cable, because the requirements from users become increased. But considering the high cost of the fiber optic cable, it is more desirable that the network architecture is composed of a spanning tree. In this paper, we present a GA (Genetic Algorithm) for solving bicriteria network topology design problems of wide-band communication networks connected with fiber optic cable, considering the connection cost, average message delay, and the network reliability We also employ the $Pr\ddot{u}fer$ number (PN) and cluster string in order to represent chromosomes. Finally, we get some experiments in order to certify that the proposed GA is the more effective and efficient method in terms of the computation time as well as the Pareto optimality.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.16-18
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• 2004

무선 센서 네트워크는 센서들을 무선으로 연결하여 데이터 교환을 통해 다양한 환경에서 정보를 수집할 수 있도록 하는 유용한 도구이다. 센서노드 간의 통신은 센서노드의 제한된 에너지를 효율적으로 이용하도록 만들어져야만 한다. 클러스터링에 기반한 계층적 라우팅 기법은 클러스터 내의 노드들은 클러스터헤드와만 통신을 하게하고 클러스터헤드가 한꺼번에 싱크에게 통합된 정보를 보내게 하여 에너지를 절약하는 기법이다. 본 연구에서는 이러한 클러스터링 기반의 라우팅에서 에너지 효율을 높이기 위해 싱크와 클러스터헤드 사이의 거리에 따른 최적 클러스터 크기를 계산하고, 원형의 전체 토폴로지에서 계산된 값과 일치됨을 확인해 보았다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1207-1213
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• 2009

A design method of network Topology for Integrated Management of various Networks is prposed and an example is shown. The TMN-DCN devices are assigned for each of the various networks. These devices have functions of network management. Also we propose the simple design methods of the network topology with survivability as one of the network management elements. The design methods are very simple but very useful. Because there is no general design algorithm for optimal topology with network survivability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1222-1227
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• 2009

In this paper, we proposed a new method, the CACH(Context-aware Clustering Hierarchy) algorithm in Mobile Ad-hoc Network(MANET) systems. The proposed CACH algorithm based on hybrid and clustering protocol that provide the reliable monitoring and control of a variety of environments for remote place. To improve the routing protocol in MANET, energy efficient routing protocol would be required as well as considering the mobility would be needed. The proposed analysis could help in defining the optimum depth of hierarchy architecture CACH utilize. Also, the proposed CACH could be used localized condition to enable adaptation and robustness for dynamic network topology protocol and this provide that our hierarchy to be resilient. As a result, our simulation results would show that a new method for CACH could find energy efficient depth of hierarchy of a cluster.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.89-97
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• 1997

A genetic algorithm (GA) is a stochastic direct search strategy that mimics the process of genetic evolution. The GA applied herein works on a population of structural designs at any one time, and uses a structured information exchange based on the principles of natural selection and wurvival of the fittest to recombine the most desirable features of the designs over a sequence of generations until the process converges to a "maximum fitness" design. Principles of genetics are adapted into a search procedure for structural optimization. The methods consist of three genetics operations mainly named selection, cross- over and mutation. In this study, a method of finding the optimum topology of truss/beam structure is pro- posed by using the GA. In order to use GA in the optimum topology problem, chromosomes to FEM elements are assigned, and a penalty function is used to include constraints into fitness function. The results show that the GA has the potential to be an effective tool for the optimal design of structures accounting for sizing, geometrical and topological variables.variables.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.38-45
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• 2016

For higher efficiency and reliability of railroad trains with many electronic sensors and actuators, a distributed control system with which electronic components communicate with each other in a distributed manner via a data network is considered. This paper considers Ethernet-based Train Communication Network (TCN) for this purpose and proposes a methodology to optimize the topology in terms of transmission latency and reliability, each of which is modeled as the number of traversing backbone nodes and the number of cables between vehicles, respectively. An objective function is derived accordingly and a closed-form optimum is obtained by relaxing the integer constraint of the number of vehicles for a unit network. Then, the final integer optimum is searched around it. Through numerical evaluation, the validity of the proposed methodology and the characteristics of the resulting solutions are shown.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.35-36
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• 2012

본 논문은 EV용 탑재형 배터리 충전기(OBC)와 같은 중 대용량 충전시스템에 적용한 Phase Shift Full Bridge Converter (PSFB) 토폴로지를 사용하는 경우, 트랜스포머의 구조에 따른 특성을 분석한다. 일반적으로 PSFB는 다른 토폴로지에 비해 코어 사용 효율이 높기 때문에 상대적으로 소형 경량화 설계가 용이하다. 그러나 수 kW급의 시스템 응용에서는 기존 코어 형상이나 Ap-limit과 제약이 따른다. 또한 특화된 코어의 경우 높은 가격으로 설계 경쟁력이 낮아진다. 따라서 본 논문에서는 이러한 대용량 PSFB의 응용 시스템에 적합한 코어 설계를 위해 다양한 트랜스포머의 구조를 선정하여 그 특성을 비교분석한다.