• 한국전산유체공학회:학술대회논문집
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• 2001.05a
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• pp.149-154
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• 2001

Parallel performance of a Myrinet based PC-cluster was tested and compared with a conventional Fast-Ethernet system. A preconditioned Navier-Stokes code was parallelized with domain decomposition technique, and used for the parallel performance test. Speed-up ratio was examined as a major performance parameter depending on the number of processor and the network topology. As was expected, Myrinet system shows a superior parallel performance to the Fast-Ethernet system even with a single network adpater for a dual processor SMP machine. A test for the dependency on problem size also shows that network communication speed is a crucial factor for parallelized computational fluid dynamics analysis and the Myrinet system is a plausible candidate for high performance parallel computing system.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.6
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• pp.106-113
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• 2017

In this paper, we propose a suitable network topology for the Ethernet based Train Communication Network (TCN) for control system in a autonomous multi-articulated vehicle. We propose a network topology considering the structural constraints such as the number of cables and ports, and the performance constraints such as network response time and maximum throughput. We compare the network performances of star topology and daisy chain topology as well as hybrid topology, which is proposed in previous studies and a compromise between daisy chain and star topology. Here, the appropriate number of nodes in a group is obtained for the configuration of the hybrid topology. We first derive estimates of the network performance through simulation with different topologies, and then, implement the network by connecting the actual devices with each network topology. The performance of each topology is measured using various network performance measurement programs and the superiority of the proposed topology is described through comparison.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.5
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• pp.659-665
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• 2013

IPCS(Inter Process Communication Service) is a real-time communication middleware designed for warship combat battle systems based on publisher-subscriber communication model. Because IPCS was originally designed to operated under 100 Mbps network environment, increasing network speed into Gigabit environment does not linearly increase the throughput of IPCS. To solve this problem, we anaylized IPCS structure and optimized IPCS into Gigabit-Ethernet environment. We found parameters to improve IPCS based on UDP and Token-ring structure. By improving, IPCS has reliability and higher throughput than TCP although IPCS is based on UDP.

• The Journal of Korea Robotics Society
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• v.18 no.3
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• pp.281-284
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• 2023

Real-time control communication network system is important for developing defense robots because it affects environmental interaction, performance, and safety. We propose a real-time control communication network using the Xenomai real-time operating system and the open-source EtherCAT master library, SOEM. EtherCAT is an Ethernet-based industrial communication method. It has low latency and many functions such as cable redundancy and distributed clock synchronization. We use Xenomai RTOS and Intel NUC to develop the system. Experimental tests demonstrate the Real-time EtherCAT master implementation, and communication with CiA301-based slave devices. The jitter measurement was conducted to validate the real-time performance of the system. The proposed system shows possibility for real-time robotics applications in various defense robots.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.10
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• pp.977-981
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• 2015

We propose a method for the implementation of an EtherCAT communication bus in a Linux-based open source Computerized Numerical Control (CNC) system. Recently, increasingly more CNC systems support real-time Ethernet protocols such as EtherCAT, which is a high-performance industrial communication protocol. For real-time CNC control over an Ethernet-based protocol, an additional layer driver needs to be implemented between the CNC system and the master of industrial communication protocol. Among the various solutions for the connection layer driver, we employ a Hardware Abstraction Layer (HAL) driver based on Linux. The operation of the implemented CNC system is demonstrated and confirmed by Hal Meter, which is used to observe the pins, signals, or parameters of HAL.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.12
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• pp.1233-1240
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• 2004

Recently the need for cooperative control among robots is increasing in a variety of industrial robot applications. Such a control framework enhances the efficiency of the real robotic assembly environment along with extending the robot application. In this paper, an ethernet-based cooperative control framework was proposed. The cooperative control of robots can multiply the handling capacity of robot system, and make it possible to implement jigless cooperation, due to realization of trajectory-synchronized movement between a master robot and slave robots. Coordinate transformation was used to relate among robots in a common coordinate. An optimized ethernet protocol of HiNet was developed to maximize the speed of communication and to minimize the error of synchronous movement. The proposed algorithm and optimization of network protocol was tested in several class of robots.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.12
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• pp.37-44
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• 2005

This paper proposes a hybrid scheme for dynamic bandwidth allocation(DBA) in Ethernet passive optical network(EPON), which combines advantages of adaptive cycle and constant cycle-based schemes. The proposed scheme is based on IPACT scheme, but it operates as adaptive cycle or constant cycle mode according to the queue status of optical line terminal(OLT) for downstream transmission. Simulation results showed that the proposed scheme could achieve a similar throughput in downstream transmission to a constant cycle-based DBA scheme, while producing a similar delay performance to the IPACT scheme in upstream transmission.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.687-693
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• 2011

In this paper, problems and solutions are proposed for applying IEC 61850 to Distribution Automation System(DAS). Communication protocol integration in power automation system have issued by IEC standards, IEC 61850 of them has researched for applying IEC 61850 to many areas of power system in spite of that it was made for substation automation system. Especially, DAS is just about to apply IEC 61850 by communication network change from serial to ethernet although DNP 3.0 is used. But it's impossible to apply directly IEC 61850 to DAS by difference of environment which unfixed wide area and separated nodes in power distribution system unlike concept of IEC 61850 is made by Substation Automation System(SAS) environment of limited space. Thus, this paper proposed applications of three types which conceptual, practical, and future to consider problems and solutions when apply IEC 61850 to Ethernet based DAS.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.983-989
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• 2012

IEEE 802.3az LPI mechanism allows an Ethernet link to reduce power consumption by entering a low-power sleeping mode and letting some components being powered off when there is no data to be transmitted through the link. However, if small amount of packets are being sent periodically, such a mechanism can not obtain energy efficiency due to a high overhead caused by excessive mode transitions. In this paper, we propose an enhanced LPI mechanism which can perform state transition adaptively based on the traffic characteristics on transport layer and network status. This simulation result shows that proposed mechanism improves energy efficiency than LPI mechanism with respect to energy consumption rate for various traffic loads.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.8
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• pp.734-741
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• 2004

This paper presents a network based fire detection system using CAN, in order to evaluate feasibility of home automation protocol for smart home. In general, because a traditional fire detection system has an analog transmission method with 4-20mA current, it has several shortcomings such as weakness to noise. Hence, as an alternative to the traditional system, this paper presents the architecture of CAN based fire detection system and the design method of CAN communication network. Also, the performance of the suggested system is evaluated through an experimental testbed. Especially, CAN has several advantages such as low cost and easiness of implementation compared to Ethernet or ARCNET, which are low layer of BACNet. Therefore, if CAN is adopted as low layer of BACNet, the home automation system is implemented more effectively.