• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.564-567
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• 2002

This paper evaluates the stability of the terminal group for he inter-vehicle communication (IVC) network with an autonomous relay access scheme. Some stability criterions such as updating rate, terminal group convergence probability and total path average holding time have been conducted by computer simulation. As the results, dynamic moving of the terminal is the serious problem that can degrade the stability of the terminal group and directly affect to overall performance of the IVC network.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2600-2602
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• 2003

오늘날의 사회는 디지털 기술기반에 의해 가속화되는 새로운 사회적, 경제적 경험의 세계로 움직이고 있다. 그 결과로서, 과거 어느 때 보다도 전력시스템, 인터넷, 통신망 등 복잡하고, 상호작용적인 네트워크의 원활한 기능에 전적으로 의존되어 가고 있고, 이러한 상황은 네트워크에 전례 없는 품질과 안정성을 부각시켰다. 또한 디지털 기기의 확산과 디지털 산업의 성장에 따른 고품질의 전력요구, 전력수급의 유형 변화, 소비자 생활양식의 변모 등에 의해 과거와는 다른 새로운 전력 시스템을 요구하고 있다. 이를 위해서는 Electricity Network와 IT Network와의 결합을 바탕으로 다단계의 지능적인 제어 능력을 보유한 전력 Super Highway가 필요하다. 본 논문은 디지털 시대를 대비한 해외의 신 전력시스템 개발 현황 및 이를 뒷받침하기 위한 네트워크 구축 방안들을 살펴보고, 이를 통해 현재 우리나라의 전력시스템 환경에서 필요한 요구조건과 가능한 네트워크 구축 방안에 대하여 살펴본다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.2
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• pp.3-17
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• 2007

Receiver access control scheme is proposed to protect multicast distribution tree from DoS(Denial-of Service) attack induced by unauthorized use of IGMP(Internet group management protocol), by extending the security-related functionality of IGMP. Based on a specific network and business model adopted for commercial deployment of IP multicast applications, key management scheme is also presented for bootstrapping the proposed access control as well as accounting and billing for CP(Content Provider), NSP(Network Service Provider), and group members.

• Korean Journal of Biological Psychiatry
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• v.12 no.2
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• pp.165-172
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• 2005

Objectives:The purpose of this study is to 1) conduct a discrimination analysis of schizophrenia and bipolar affective disorder using MMPI profile through artificial neural network analysis and logistic regression analysis, 2) to make a comparison between advantages and disadvantages of the two methods, and 3) to demonstrate the usefulness of artificial neural network analysis of psychiatric data. Procedure:The MMPI profiles for 181 schizophrenia and bipolar affective disorder patients were selected. Of these profiles, 50 were randomly placed in the learning group and the remaining 131 were placed in the validation group. The artificial neural network was trained using the profiles of the learning group and the 131 profiles of the validation group were analyzed. A logistic regression analysis was then conducted in a similar manner. The results of the two analyses were compared and contrasted using sensitivity, specificity, ROC curves, and kappa index. Results:Logistic regression analysis and artificial neural network analysis both exhibited satisfactory discriminating ability at Kappa index of greater than 0.4. The comparison of the two methods revealed artificial neural network analysis is superior to logistic regression analysis in its discriminating capacity, displaying higher values of Kappa index, specificity, and AUC(Area Under the Curve) of ROC curve than those of logistic regression analysis. Conclusion:Artificial neural network analysis is a new tool whose frequency of use has been increasing for its superiority in nonlinear applications. However, it does possess insufficiencies such as difficulties in understanding the relationship between dependent and independent variables. Nevertheless, when used in conjunction with other analysis tools which supplement it, such as the logistic regression analysis, it may serve as a powerful tool for psychiatric data analysis.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.3
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• pp.18-31
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• 2004

Ecological network can solve the ecological problems such as habitat cutting and fragmentation that are resulted from urbanization. Recently, rooftop biotope construction has been appeared as a usefull method for ecological networking in urban area. The objective of this study is to seek the possibility of rooftop greening introduction as well as to select target species for rooftop greening construction from the urban ecological network point of view. In order to select target species, we monitored two adjacent rooftop greening sites, where we found 22 species of birds and insects and 33 species of plants. We set criteria to select target species through documents research, and gave marks species according to the criteria with the help of specialists. We divided the target species into 5 groups on the basis of the 12 selecting criteria. In those two monitored rooftop greening sites, we did not find any species belong to group A, which is the best target species, but we found species belong to the other groups. Orthetrum albistylum, Sympetrum dawinianum belong to group B, which is the priority target species, 7 species besides Passer montanus, Coccinella axyridis, Agrionidae to group C, which is the possible target species, 6 species besides Atractomorpha lata to group D, which is the potential target species, and the others were found to be inadequate to the target species. We found Orthetrum albistylum, Sympetrum dawi-nianum to be the best appropriate target species in the two sites. According to the result of this study, the method of ecological network construction from the dra-gonfly habitat network point of view through the construction of rooftop habitat is ideal for Orthetrum albistylum, and Sympetrum dawinianum. For successful urban ecological network construction, selection criteria and construction techniqes & methods for rooftop habitat should be developed through future research.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.5
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• pp.809-816
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• 2024

In a Wireless Sensor Network (WSN) environment, where numerous small sensors are arranged in a certain space to form a wireless network, each sensor has limited battery power. Therefore, the lifetime of each sensor node is directly related to the network's lifetime, necessitating efficient routing to maximize the network's lifespan. This study proposes a routing protocol based on PEGASIS, a representative energy-efficient routing protocol in WSN environments. The proposed protocol categorizes nodes into groups based on their distance from the sink node, forms multiple chains within each group, and selects the leader node for each group by comparing the remaining energy levels. The proposed method ensures that each group's leader node is the one with the highest energy within that group, which has been shown to increase the network's lifespan compared to the traditional PEGASIS method.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.90-90
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• 2004

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.222-225
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• 2005

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.3
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• pp.207-215
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• 2013

This paper is channel assignment and scheduling techniques for efficient wireless AMI network. In AMI system, the multi-channel cluster network to be proposed defines the communication channel between NC (Network Coordinator) and CDA (Clustered Data Aggregator) as the network channel. CDA and OMD(Out Meter display) and communication channel between SMD(Smart Meter Device) are defined as the group channel. AMI network of the multi-channel cluster based in which the network channel and group channel is mixed increases the administration efficiency through the physical/logical consumer channel clustering. The reliability of inspection data through the channel use distinguished between the adjacent cluster is enhanced. In addition, the fast aggregation of data is possible and the size of a metering network is increased through the channel allocation of the multichannel cluster based.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1256-1264
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• 2011

MBS (Multicast Broadcast Service) is defined in WiBro networks for implementing multicast-based services. However, most of the WiBro networks currently used in Korea do not have the MBS functionality and it causes some difficulty in implementing multicast-based services. This paper evaluates the performance of VoIP-based group communication services when implementing using the following two cases: unicast-based and multicast-based group communication systems. The performance evaluation is done using QualNet for each case in terms of the amount of network resource for the service, the delay and delay jitter of packets, and the difference of the delay of members in a group. The simulation result shows that the number of groups and members in a group in a WiBro network is limited because the amount of network resource for the service is increased according to the number of members in a group, and so, the MBS service is required in a WiBro network for a fully-fledged service of VoIP-based group communications. The simulation result also shows that, when a packet bundling is used, the number of groups and members in a group that can be supported in a WiBro network can be increased due to the decrease of the amount of network resource for the service.