• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.19-22
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• 2004

A 30-inch WQXGA+ TFT-LCD Monitor has been developed based on in-plane switching mode with multi-domain. This product adopts Cu electrode which, in spite of low resistivity, was not applied to TFT LCD products because of productivity and reliability problems etc. This low resistivity material makes it possible to clear the problem caused by line delay in such high resolution TFT-LCDs. As a results of successful adoption of innovative materials and technologies, our world's largest TFT-LCD Monitor has best performance for high information display.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.415-419
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• 2003

This paper focuses on a simple technique to reduced torque ripple in the direct torque control inverter for PMSM drive. It is actually impossible to raise the inverter switching frequency in the conventional system, although the hysterisis bandwidths for the stator flux and torque control are sufficiently diminished, because of the sampling Interval and the delay in estimating the flux and the torque In order to overcome the problem, the proposed method introduces a dithering technique into the conventional system by superposing triangular waves with high frequency and minute amplitude on the torque error. And the programable 3- stage lowpass filter is added instead of pure Integrator. Simulation results prove the feasibility of proposed strategy compared with conventional method.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.629-637
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• 2000

Unbalance between user requirements and insufficient network resources makes a congestion. In the future since the communication networks will have very heavy traffic congestion will be more serious. The ATM networks was recommended to support the B-ISDN service for the future multimedia communication. In thie sense of congestion avoidance and recovery the ABR service category in ATM networks allows the feedback flow control mechanism to dynamically allocate the idle bandwidth of the network to users fairly and to control the network congestion rapidly In this paper we introduce a congestion control scheme using systematical approach to confirm robust stability with respect to unknown round trip delay for the network which has both unicast and multicast connections.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.3
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• pp.225-231
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• 1992

In this paper, queuing networks with open chains are considerd to analyze the performance of packet switching networks. Networks are classified into backbone and local access networks. Networks for performance analysis are distributed to twelve regions and DNS is the backbone. Analysis was conducted using the real values from the input to existing networks and mathematical estimation values. As the result of analysis, the mean of end-to-and delay for each chain was presented. Except special regions, we found that there was a little difference between real values and mathematical estimation values. However, there could be a performance problem in total networks due to the increase of communication volumes in each region. So we proposed some solutions to this problem.

• Journal of Korea Multimedia Society
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• v.2 no.2
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• pp.176-183
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• 1999

Using Asynchronous Transfer Mode(ATM) which is a high-bandwidth, low-delay, cell switching and multiplexing technology, Broadband-Integrated Services Digital Network (B-ISDN) can support communication services of all kinds. To evaluate the performance of ATM networks, traffic source models to meet the requirements are demanded. We can obtain random traffic distribution for ATM networks by using the Cellular Automata (CA) which have effective random pattern generation capability. In this paper we propose an algorithm using 2-D LHCA to generate more effective random patterns with good random characteristics. And we show that the randomness by 2-D LHCA is better than that of the randomness by 1-D LHCA.

• Journal of Power Electronics
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• v.18 no.4
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• pp.1086-1098
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• 2018

This study presents a new sensorless commutation method for brushless direct current motors to replace Hall sensor signals with virtual Hall signals. The importance of the proposed method lies in the simultaneous elimination of the phase shifter and the low-pass filters, which makes the method simple and cost-effective. The method removes high ripple switching noises from motor terminals, thereby decreasing motor losses. The proposed method utilizes unfiltered line voltages with notches caused by current commutation. Hence, specific sign signals are defined to compensate for the effects of commutation noise. The proposed method is free from phase delay that originates from low-pass filters. The method directly produces virtual Hall signals, and thus, it can be interfaced with low-cost commercial commutation integrated circuits based on Hall sensors. Simulation and experimental results show the effectiveness and validity of the proposed method.

• Annual Conference of KIPS
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• 2001.10b
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• pp.1533-1536
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• 2001

This paper considers the TMN system for management of public ATM switching network which has the four-level hierarchical structure consisting of one network management system, a few element management system and several agent-ATM switch pairs, respectively. The effects of one TMN command on the local call processing performance of the component ATM switch an analyzed using Jackson's queueing model. The TMN command considered is the permanent virtual call connection, and the performance measures of ATM switch are the utilization, mean queue length and mean waiting time for the processor interfacing the subscriber lines and trunks directly, and the call setup delay of the ATM switch.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.3
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• pp.136-141
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• 2007

In this paper, a new simple control method for active power filter which can realized the complete compensation of the harmonic currents is proposed. In the proposed scheme, a compensating current reference generator employing resonance model implemented by a DSP(Digital Signal Processor) is introduced. Deadbeat control is employed to control the active power filter. The switching pulse width based SVM(Space Vector Modulation) is adopted so that the current of active power filter is been exactly equal to its reference at the next sampling instant. To compensate the computation delay of digital controller, the prediction of current is achieved by the current observer with deadbeat response.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.11a
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• pp.93-96
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• 1993

BiCMOS technology, which combines CMOS and bipolar technology, offers the possibility of achieving both very high density and high performance. In this paper, the characteristics of BiCMOS and CMOS circuits, especilly the delay time is studied. BiCMOS inverter, which has high drive ability because of bipolar transistor, drives high load capacitance and has low-power characteristics because the current flows only during switching transient just like the CMOS gate. BiCMOS inverter has the less dependence on load capacitance than CMOS inverter. SPICE that has been used for electronic circuit analysis is chosen to simulate these circuits and the characteristics is discussed.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.5
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• pp.199-204
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• 2006

To develop a safety-critical network in nuclear power plants that puts more stringent requirements than the competitive commercial ones do, we establish four design criteria - deterministic communication, explicit separation/isolation structure, reliability, verification & validation. According to those design criteria, the fundamental design elements are chosen as follows - a star topology, point-to-point physical link, connection-oriented link control and fixed allocation access control. After analyzing the design elements, we also build a communication architecture with TDM (Time Division Multiplexing) bus switching scheme. Finally, We develop a DDCNet (Deterministic Data Communication Network) based on the established architecture. The DDCNet is composed of 64 nodes and guarantees the transmission bandwidth of 10Mbps and the delay of 10 msec for each node. It turns out that the DDCNet satisfies the aforementioned design criteria and can be adequately utilized for our purpose.