• 한국정밀공학회지
• /
• 제15권2호
• /
• pp.35-44
• /
• 1998

This paper describes multiple fault diagnosis method in complex system with hierarchical structure. Complex system is divided into subsystem, item and component. For diagnosing this hierarchical complex system, it is necessary to implement special neural network. We introduced Modular Artificial Neural Network(MANN) for this purpose. MANN consists of four level neural network, first level for symptom classification, second level for item fault diagnosis, third level for component symptom classification, forth level for component fault diagnosis. Each network is multi layer perceptron with 7 inputs, 30 hidden node and 7 outputs trained by backpropagation. UNIX IPC(Inter Process Communication) is used for implementing MANN with multitasking and message transfer between processes in SUN workstation. We tested MANN in reactor system.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 1998년도 추계종합학술대회
• /
• pp.442-445
• /
• 1998

본 논문은 56Kbps 모뎀을 이용하는 전화망 가입자나 터미널 어댑터를 사용하는 ISDN 가입자가 인터넷 정합장치를 이용하여 사용자 ID없이 개방제로 인터넷에 접속하여 서비스를 받고, 유료 정보제공자에 대한 대체인증 기능 및 과금회수대행 기능을 제공하는 인터넷 정합시스템(WNAS: Web Network Access System)의 설계 및 구현에 관한 내용이다. 본 논문에서는 웹 기반의 인터넷 정합장치에 최대 120/60가입자가 동시에 파일 받기/보내기를 했을 경우 시스템의 전송속도를 분석하였다.

• 제어로봇시스템학회논문지
• /
• 제6권10호
• /
• pp.911-917
• /
• 2000

As many sensors and actuators are used in various automated systems, the application of network to real-time distributed control system is gaining acceptance in many industries. In order to take advantages of networking, however, the network should be carefully designed to satisfy real-time distributed control. This paper presents an implementation method of closed-loop control using Profibus-FMS. In order to implement a closed-loop control system, we used industrial computers with Profibus-FMS network cards and a DC servo motor. Through various experiments, the step response of the control system with network was compared with the reference response without network.

• Journal of Mechanical Science and Technology
• /
• 제20권7호
• /
• pp.929-940
• /
• 2006

Early detection and diagnosis of incipient induction machine faults increases machinery availability, reduces consequential damage, and improves operational efficiency. However, fault detection using analytical methods is not always possible because it requires perfect knowledge of a process model. This paper proposes a neural network based expert system for diagnosing problems with induction motors using vibration analysis. The short-time Fourier transform (STFT) is used to process the quasi-steady vibration signals, and the neural network is trained and tested using the vibration spectra. The efficiency of the developed neural network expert system is evaluated. The results show that a neural network expert system can be developed based on vibration measurements acquired on-line from the machine.

• 한국시스템다이내믹스연구
• /
• 제1권2호
• /
• pp.61-89
• /
• 2000

The purpose of this study is first, to find out what factors affect the cooperation and trust within the functions in the policy implementation network and in what mechanism these factors interact, second to investigate the whys to manage trust and cooperation successfully in the dynamic situation such as the network setting. For these purpose, this study reviews the concept and characteristics of policy implementation organizations, second, extracts the various factors affecting trust and cooperation in the network situation, third applies and analyzes the relationship among factors to system dynamics model based on the game theory. The results of this study could be summarized as follows: It was found that the utility change within the participants by persuasion ＆ mutual understanding and change of rule would be leading to success in policy implementation network. Also bureaucratic management such as power enforcement does not have any good impact in the managing network. In this study, system simulation method tried to analyze the hypothesis. Quantitative and case analyses were not accompanied and analysis was limited to two-person game theory. So there is some doubt this results could be generalized to actual situation which is N-person game.

• 설비공학논문집
• /
• 제15권3호
• /
• pp.159-165
• /
• 2003

The fault detection and diagnosis technology may be applied in order to decrease the energy consumption and the maintenance cost of the air-conditioning system. To detect partial faults of the air-conditioning system, a neural network algorithm may be used. In this study, the neural network algorithm using normalized input data by the standard deviation was applied. And the [7$\times$10$\times$10$\times$1] neural network structure was selected. Test results showed that the neural network algorithm using normalized input data was very effective to detect the condenser fouling and the evaporator fan fault of an air-conditioning system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 D
• /
• pp.2328-2330
• /
• 2003

This paper presents a new design methodology of networked control system using CAN(Controller Area Network). Feedback control systems having control loops closed through a network are called networked control systems. We design CAN nodes which can transmit control and monitoring data through network bus and apply these to networked control system design. We analyze the variation of stability property according to network-induced delay and determine a proper sampling period of networked control system that preserves stability performance. The results of the experimental example validate effectiveness of our networked control system.

• 디지털콘텐츠학회 논문지
• /
• 제9권1호
• /
• pp.33-39
• /
• 2008

Ad Hoc Network는 인프라스트럭처 기반의 네트워크가 아니고 노드들이 분포되어 있기 때문에 공격을 받기가 쉽다. 침입탐지시스템은 다른 노드들의 신뢰 수준을 감지하고 노드의 로컬 보안에 대한 검사와 감시 능력을 제공한다. 본 논문에서는 침입 탐지를 하는데 오버헤드를 줄이기 위해 클러스터링 기법을 적용하였다. 그리고 노드들 간의 신뢰도를 측정하기 위해 클러스터 헤드가 멤버 노드로부터 받은 신뢰 정보와 자신의 정보를 조합하여 다른 노드의 신뢰도를 평가한다. 이렇게 함으로써 네트워크내의 노드들의 대한 인증을 정확하게 수행할 수 있게 되어 안전한 데이터 전송을 제공하게 된다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
• /
• pp.403-405
• /
• 2004

This paper describes an implementation of Home network Control Protocol(HnCP) and it's application to an Intelligent lighting system. The HnCP was announced by korea PLC forum in June 2003 to provide a network protocol for PLC based home appliances. The HnCP master and HnCP slaves were implemented using XPLC30 which is an SOC with ARM9 core. The efficacy of the developed HnCP network modules were shown by applying them to a intelligent lighting system composed of dimmable fluorescent lamps. An extended message set was proposed for the intelligent lighting system and we proposed some directions for the future development of HnCP.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권4호
• /
• pp.1841-1865
• /
• 2017

This paper proposes a new interference mitigation scheme for device-to-device (D2D) communications underlaying a cellular network. The object of the proposed scheme is to determine the number of data streams, a precoding matrix, and a decoding matrix of D2D networks so as to maximize the system capacity given the number of data streams of a cellular network while satisfying the constraint of the inter-system interference from D2D networks to the cellular network. Unlike existing interference mitigation schemes based on the interference alignment technique, the proposed scheme operates properly regardless of the number of data streams of a cellular network and moreover it does not require changing the precoding and decoding matrices of a cellular network. The simulation results demonstrate that the proposed scheme significantly increases the system capacity by mitigating the intra- and inter-system interference.