• 전기학회논문지
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• 제58권1호
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• pp.63-68
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• 2009

As the complexity of the power system becomes higher, tests of the new devices, such as exciter and PCS(Power Conversion System) of the distributed generation sources, in the real operating condition are more important. However tests of the unverified devices in the real power system may cause hazardous malfunction of the system. In order to avoid this problem, power devices may be tested with the real-time simulators instead of the real power system. This paper presents an real-time multi machine power system simulator using PCs(Personal Computer) and Fast Ethernet. Developed real-time simulator performs the electro-mechanical dynamic simulation of multi-machine power system by the network distributed computing technique. Because the simulator consists of usual PCs and Fast Ethernet, it is possible to make up a simulation system very cheaper than the conventional real-time simulator which consists of dedicated expensive hardware devices. The performance of the developed simulator is tested and verified with the scaled model excitation system. The test which adjust the control parameters of the exciter is performed with the well-known New England 10 generator 39 bus sample power system.

• International Journal of Control, Automation, and Systems
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• 제3권4호
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• pp.591-600
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• 2005

In this paper, we discuss real-time control of networked control systems (NCSs) and practical issues in the choice of the communication networks for this purpose. An appropriate integration of control systems, real-time environments, and network communication systems allows the optimization of the quality-of-control (QoC) in NCSs. We compare several prevailing network types that may be used in control applications to offer a guideline of choosing a proper network. A real-time operating environment is also presented as an important ingredient of NCS design. To evaluate its feasibility and effectiveness, a real-time NCS containing a ball magnetic levitation (Maglev) setup is implemented via an Ethernet. Based on the experimental results, it is concluded in this paper that real-time control via Ethernet is a practical and feasible solution to NCS design.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.350-353
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• 2004

The increasing use of Ethernet-TCP/IP network in industry has led to the growing interest in its reliability in real-time applications such as automated manufacturing systems and process control systems. However, stochastic behavior of its medium access scheme makes it inadequate for time-critical applications. In order to guarantee hard real-time communication service in Ethernet-TCP/IP network, we proposed an algorithm running over TCP/IP protocol stack without modification of protocols. In this paper, we consider communication services guaranteeing deadlines of periodic real-time messages over MAC protocols that have unbounded medium access time. We propose a centralized token scheduling scheme for multiple access networks. The token is used to allow a station to transmit its message during the time amount that is appended to the token. The real-time performance of the proposed algorithm has been described.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.151-154
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• 2003

In this paper, we described a method to guarantee a real-time communication in the hetegeneous network for the personal robot. The hetegeneous network is composed of many kinds of network like IEEE1394, Ethernet, CAN, Bluetooth, Wireless Lan and so on. real-time data is transfered via those kinds of network. Those network have different characteristics as speed, bandwidth, Priority. we used IEEE1394, Ethernet, CAN to study in this paper. To guarantee a real-time communication, a worst case response time must be scalable. In this environment to guarantee a real-time communication, we get a worst case response time of each network and a end-to-end worst case response time.

• 시스템엔지니어링학술지
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• 제13권2호
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• pp.9-17
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• 2017

Concept development of a real-time Field Programmable Gate Array (FPGA)-based switched Ethernet data communication network for the Man-Machine Interface System (MMIS) is presented in this paper. The proposed design discussed in this research is based on the systems engineering (SE) approach. The design methodology is effectively developed by defining the concept development stage of the life-cycle model consisting of three successive phases, which are developed and discussed: needs analysis; concept exploration; and concept definition. This life-cycle model is used to develop an FPGA-based time-triggered Ethernet (TTE) switched data communication network for the non-safety division of MMIS system to provide real-time data transfer from the safety control systems to the non-safety division of MMIS and between the non-safety systems including control, monitoring, and information display systems. The original IEEE standard 802.3 Ethernet networks were not typically designed or implemented for providing real-time data transmission, however implementing a network that provides both real-time and on-demand data transmission is achievable using the real-time Ethernet technology. To develop the design effectively, context diagrams are implied. Conformance to the stakeholders needs, system requirements, and relevant codes and standards together with utilizing the TTE technology are used to analyze, synthesize, and develop the MMIS non-safety data communication network of the APR1400 nuclear power plant.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.133.3-133
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• 2001

This paper analyses the real-time performance of Ethernet based intranet whether it is applicable to the real-time network. Unpredictability of transmission delay by collision-delay-retransmission mechanism in CAMA/CD(Carrier Sense Multiple Access with Collision Detect) of Ethernet is the major reason making hard to apply to real-time system. Both retransmission mechanism of TCP(Transmission Control Protocol) for reliability and sliding windows algorithm for high utilization make hard to predict transmission delay. Because real-time control network require fast responsibility and bustle of short-periodic messages, global-clock for collision avoidance and UDP(User Datagram Protocol) for high utilization of network are used. The mathematical models for time-delay that can be occured between ...

• 에너지공학
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• 제14권2호
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• pp.112-116
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• 2005

본 논문에서는 높은 대역폭과 안정성을 제공하는 DCS용 통신망의 구조를 제시하고 성능을 해석한다. 본 논문에서 제시하는 DCS용 통신망은 DCS 통신망에서 널리 사용되는 리플렉티브 메모리 (Reflective Memory) 구조를 채용하며, 이에 따라 링형 토폴로지를 가진다 물리계층으로 사무용 및 산업용으로 널리 쓰이고 있는 패스트 이더넷(Fast Ethernet)물리 매체를 사용하여 100 Mbps의 대역폭을 가지고, 링형 토폴로지가 가지는 단점인 각 노드에서의 시간 지연을 줄이기 위해 RED(Ring Enhancement Device)라는 장치를 고안하여 사용한다. 본 논문에서 소개하는 DCS용 통신망을 ERCNet(Ethernet based Real-time Control Network)이라고 명명하며, ERCNet의 구조와 동작에 대해 설명한다. ERCNet의 통신 성능에 대한 수학적 해석을 수행하고 개발된 ERCNet을 이용한 실험을 통하여 해석 결과의 정확성과 통신망 성능을 검증한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.1129-1132
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• 1999

This paper deals with the design and implementation of an Ethernet-based communication protocol to be used in PC-based I/O interface systems. Recently, the performance of PC systems is being highly improved and Ethernet is used as the stable communication network over the world. We develop a new protocol driver with the capability of accessing Ethernet directly using NDIS(Network Driver Interface Specification), the network interface standard of Windows O.S. in PC, and install it at the application layer of the protocol structure. Its major roles are the supplement of CSMA/CD algorithm, the effective use of the long data frame of Ethernet, and the real-time transmission of data frames. This paper represents the possibility of the real-time control network and systems based on PCs and Ethernet.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1836-1839
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• 2005

We have developed Ethernet based real-time communication systems called "Vnet/IP" for DCS which is the control system for process automation. This paper describes the features and the technologies of the ASIC which is utilized in the communication interface hardware for Vnet/IP. Vnet/IP has been developed for mission-critical communications. Hence it has real-time feature, high reliability and precise time synchronization capability. At the same time, it is able to deal with standard protocols without influence on mission-critical communications. The communication interface hardware has a host interface and dual redundant network interfaces. The host interface can be chosen PCI-bus or R-bus which is the proprietary internal bus developed for the high reliable redundant controller. Each network interface is a RJ45 connection with 1Gbps maximum in compliance with IEEE802.3.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.136-138
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• 2006

Recently, network systems are widely used in several areas, and some considerable attentions have been directed to the Networked Control System(NCS). In NCS, network-induced delays are inevitable, and they sometimes degrade the performance of networked control systems to be a source of potential instability. In this paper, We proposes a compensation method for networked control system subject to network-induced delays by using a simple method, which is based on a sort of predictive strategy. To evaluate its feasibility and effectiveness, a real-time NCS for a rotary inverted pendulum is implemented via an Ethernet. Based on the experimental results. we show that the proposed simple method can be a practical and feasible solution to NCS design.