• 한국초등과학교육학회지:초등과학교육
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• 제37권1호
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• pp.39-53
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• 2018

The purpose of this study was to investigate the conceptual structure of subjects related to matter having pre-service elementary school teachers by applying semantic network analysis (SNA). The analyzed concepts in the subjects of matter were 6 words such as 'atom', 'molecule', 'ion', 'electron', 'matter' and 'particle'. The results of SNA of the concepts are as follows : 1. In the semantic network of 'atom', words having a high betweenness centrality were linked with the words based on both the scientific context and the everyday context. 2. The network of 'molecule' was analyzed to be more organized than the network of the 'atom'. 3. In the network of 'ion', the group of words of the scientific context was distinguished from the group of words of the everyday context. 4. The network of 'electron' was analyzed to be more oriented on electricity and magnetism in the field of physics. 5. In the network of 'matter', the words related to compounds were linked with knowledge of history of science. 6. The network of 'particle' was not structured with words based on particulate nature of matter.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(1)
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• pp.367-370
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• 2002

In this paper, we propose a new node architecture LonWorh control Network for home network system environmint using power line communications. Using conventional Lon Work technology is a many disputable points for home network. LonWork network system needs high-cost development equipment. Moreover, conventional Lon Work system can not implement high-grade algorithms and variety application operation. because of the limitation of processing ability in Neuron chip. For that reason, the proposed structure is applicable to low-cost and more complex applications which are impossible in home network using conventional Lonworks structure. The proposed structure is implemented with some hardware and かone software for power line home network. The physical layer and the MAC layer of the LonTalk protocol within ton Work are implemented in hardware, which decreases the development costs communication processor. The upper of link layer of the LonTalk protocol is implemented with software, which decreases the development costs of software and increases the flexibility of tile system and increases the extension of the system. We verified the commercial feasibility of the proposed system through the power line tests with the existing LonWorks network in home network. As a result, it is concluded that the proposed architecture provides increasing flexibility and decreasing cost of the system.

• 산업진흥연구
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• 제2권2호
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• pp.1-6
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• 2017

한국전력의 전력을 생산, 수송, 공급하는 3가지 업무분야 중 수송부분을 관리하는 서울전력관리처에 SCADA (Supervisery Control And Data Acquisition) System이 1980년 처음 도입된 후 중앙급전소, 지역급전소, 변전소 업무를 EMS, SCADA, RTU 컴퓨터 설비 3계층의 1:N 식 방사상 형태로 구성하여 HARRIS 6000, BSC, HDLC, L&N, 도시바 등 5개 Protocol로 1200 bps와 9600 bps로 Data Link를 이용하여 왔다. 본 연구는 OSI표준네트워크패킷흐름을 도시하여 DataLink와 Network Layer를 분석하고, 네트워크 3계층을 사용하는 X.25 고속 통신망으로 구성된 한국전력 SCADA 네트워크 모델을 제시하였으며, 통신망을 시험 평가하였다. 현재의 스카다 통신구조를 개선한 미래 스카다 통신구조를 제시하고, SCADA DB 구조를 정의하고, 스카다 기능 구조에 원격 SCADA 게이트웨이 개념을 도입 표준 통신프로토콜을 적용 하였다. 따라서 데이터 전송시간 제약완화, 타지역 타 설비에서의 감시 및 제어의 다중화 및 통신 개방성을 확보하도록 하였다.

• 한국농공학회논문집
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• 제53권1호
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• pp.1-7
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• 2011

The nature of a network implies movement among vertices, and can be regarded as flows. Based on the flow concept which network follows the hydraulic fluid principle, we develop a spatial network model using Bernoulli equation. Then we explore the organization of spatial network and growth by the velocity of network flows. Results show that flow velocity determines network connections or influence of a vertex up to a point, and that the overall network structure is the result of pull force (pressure) and flow velocity. We demonstrate how one vertex can monopolize connections within a network.

• 한국콘텐츠학회논문지
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• 제7권7호
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• pp.1-10
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• 2007

본 논문에서는 도로망에서 이동하는 객체들의 현재 위치를 효율적으로 갱신하는 색인 기법을 제안한다. 기존의 도로망 모델은 이웃한 도로 세그먼트의 연결 정보를 포함하지 않기 때문에 객체가 이웃한 도로 세그먼트로 이동할 때 갱신 성능을 저하시킨다. 본 논문에서는 이러한 문제점을 해결하기 위해 교차점 기반 도로망 모델과 새로운 색인 구조를 제안한다. 제안하는 교차점 기반 도로망 모델은 도로를 분할할 때 교차점을 포함하도록 분할하여 연결 정보가 유지되도록 한다. 성능 평가를 통해 제안하는 색인 기법이 기존 색인 구조에 비해 이동 객체의 갱신 성능이 3배 향상됨을 보인다.

• 농촌계획
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• 제23권2호
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• pp.43-54
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• 2017

When an age of low growth and population decline, population migration plays an important role in spatial structure of region. There have been many researches on migration and regional spatial structure. The purpose of this study is to examine the changes of Gwangju and Jeonnam region's spatial structure and central area using social network analysis methods. For analysis it was used that population and migration data and passenger OD(Origin and Destination) travel data released by Statistics Korea and Korea Transport Database(KTDB). Using Gephi 0.8.2, migration and passenger OD networks were visualized, and this describe network flow and density. The results of the network centrality analysis show that the most populated village is not always network center though population mass is an important factor of central places. The average eigenvector centrality of 2010 migration is the lowest during 2005-2015, and it means few regions have high centralities. When comparing migration and travel networks, travel data is more effective than migration data in determining the central location considering spatial functions.

• 정보처리학회논문지A
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• 제8A권1호
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• pp.56-62
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• 2001

This paper presents a neural network based variable structure control scheme for nonlinear systems. In this scheme, a set of local variable structure control laws are designed on the basis of the linear models about preselected representative points which cover the range of the system operation of interest. From the combination of the set of local variable structure control laws, neural networks infer the approximate control input in between the operating points. The neural network based variable structure control alleviates the effects of model uncertainties, which cannot be compensated by the control techniques using feedback linearization. It also relaxes the discontinuity in the system’s behavior that appears when the control schemes based on the family of the linear models are applied to nonlinear systems. Simulation results of a ball and beam system, to which feedback linearization cannot be applied, demonstrate the feasibility of the proposed method.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2001년도 추계학술대회 학술발표 논문집
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• pp.221-224
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• 2001

In this paper, we propose the initial optimized structure of the Radial Basis Function Network which is more simple in the part on the structure and converges more faster than Neural Network with the analysis method using Time-Frequency Localization and genetic algorithm. When we construct the hidden node with the Radial Basis Function whose localization is similar with an approximation target function in the plane of the Time and Frequency, we have initial structure of RBFN, After that, we evaluate the parameters of RBF in the network and the parameters needed for the network is more a few. Finally, we make a good decision of the initial structure having an ability of approximation.

• 제어로봇시스템학회논문지
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• 제5권8호
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• pp.898-906
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• 1999

A control structure is introduced for the purpose of rejecting periodic (or repetitive) disturbances on a tracking system. The objective of the proposed structure is to drive the output of the system to the reference input that will result in perfect following without any changing the inner configuration of the system. The structure includes an adaptation block which learns the dynamics of the periodic disturbance and forces the interferences, caused by disturbances, on the output of the system to be reduced. Since the control structure acquires the dynamics of the disturbance by on-line adaptation, it is possible to generate control signals that reject any slowly varying time-periodic disturbance provided that its amplitude is bounded. The artificial neural network is adopted as the adaptation block. The adaptation is done at an on-line process. For this , the real-time recurrent learning (RTRL) algoritnm is applied to the training of the artificial neural network.

• 기술혁신연구
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• 제14권2호
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• pp.143-165
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• 2006

By analyzing five in-depth case studies of suppliers in newly emerging Vietnam's motorcycle industry, this paper explores the differences in patterns and processes of capability improvement of suppliers who participate in different kinds of supplier-assembler network with different structures. The paper finds the correlation between the kinds of suppliers' capabilities improved and the structure of networks they participate in. While suppliers in arm-length networks can improve more upstream capabilities (structure design, process desist), suppliers in embedded networks can improve more downstream capabilities (process design, process setup, process maintenance and delivery control). Two capability improvement patterns of firms in newly emerging economy are indicated. The first pattern is asymmetrical improvement, either upstream or downstream capabilities, by participating in either arm-length or embedded networks. This pattern obstructs the suppliers to meet the requirements of new buyers rho come from different kinds of network. The second pattern is symmetrical improvement by joining both arm-length and embedded networks.