• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.450-453
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• 2009

Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of SiC-based electroconductive ceramic composites. Compare economic estimation of SiC ceramic heater with sheathe heater are as followings. (1) Temperature rising time of sheath heater is 1.1 times faster than SiC ceramic heater. (2) Heating insulation of SiC ceramic heater is 2.7 times larger than sheath heater. If SiC ceramic heater is one body type of a product application, contact resistance will decrease. I think that temperature initial rising time is faster than now. The more SiC ceramic heater is used for a long time, the more economic benefit is larger in the view point of heat insulation.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.178-180
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• 2003

This paper proposes a real-time simulator that can simulate dynamic changes of a substation for intelligent SCADA system. The simulator consists of RTDS, voltage and current amplifier, IED, and RTU. The simulator is verified by system implementation and event simulation of a substation.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3162-3164
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• 1999

In this paper, a temperature compensating system(TCS) for LPG dispenser has been developed. A TCS includes a processor(80C196) with an AID converter. I/O port(82C55) and 6-digit vacuum fluorescent display. Based on encoding signals from the gas flow meter, different calibration values from each apparatus and temperature compensating values from the temperature sensor, the TCS controls the LPG dispensing quantity with switching on or off the solenoid valves. The temperature compensation is performed with analog-to-digital conversion of the temperature sensor. The resolution of temperature compensation is nearly $0.5^{\circ}C$ using 10-bit ADC. The field test of the TCS shows the exact temperature compensation.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.606-608
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• 1996

In this paper, a new control scheme based on deadbeat control with disturbance observer for voltage controlled Inverter system is proposed. The inverter system is modelled as the 4th-order system treating R load current variation caused by disturbance. So the disturbance observer exists in the state observer. By using the pole placement strategy, the observer estimates the state and disturbance variable of the next sampling instant. Simulation results so show that The proposed scheme has robust feature against disturbance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5C
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• pp.406-414
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• 2005

The necessity for a technique to protect intellectual property of a digital content has been increasing, especially for the image/video contents which are the most favorite because of their high information-intensive property. According to this demand, this paper proposed a digital watermarking algorithm, which is recognized as the most promising technique. This algorithm targets MPEG compression system and the watermarking process is to be performed during the compression process. It inserts watermark only in Y components of I-frames. Experimental results showed that the proposed method satisfied both imperceptibility and robustness against various attacks. The PSNR difference between the compressed images(the average compression ratio was about 27:1 with Y:Cb:Cr=4:2:0 color format for TM5-based compression) with and without watermarking was only 1.8dB ($4.2\%$). In each case that the resulting image after an attack was reusable the normalized correlation between the extracted watermark and the original one was above 0.8.

• Journal of Digital Contents Society
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• v.10 no.4
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• pp.579-585
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• 2009

In [9], Tyrtshnikov proposed a preconditioned approach to derive a general solution from a Toeplitz linear system. Furthermore, the process of selecting a preconditioner matrix from symmetric Toeplitz matrix, which has been used in previous studies, is introduced. This research introduces a new method for finding the preconditioner in a Toeplitz system. Also, through analyzing these preconditioners, it is derived that eigenvalues of a symmetric Toeplitz are very close to eigenvalues of a new preconditioner for T. It is shown that if the spectrum of the preconditioned system $C_0^{-1}T$ is clustered around 1, then the convergence rate of the preconditioned system is superlinear. From these results, it is determined to get the superliner at the convergence rate by our good preconditioner $C_0$. Moreover, an advantage is driven by increasing various applications i. e. image processing, signal processing, etc. in this study from the proposed preconditioners for Toeplitz matrices. Another characteristic, which this research holds, is that the preconditioner retains the properties of the Toeplitz matrix.

• Journal of Digital Contents Society
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• v.7 no.3
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• pp.147-151
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• 2006

In recent years, the Internation Standard ISO/IEC 18000-6 is announced and a new scheme of Type C is added to conventional standard. Among the RFID systems the ISO/IEC 18000-6 standard is the most interesting to companies due to its potential market growth. The operating frequency is between 860-960 MHz, and three kinds of RFID system are included in the standard, i.e. type A, B and C. In this paper, we implemented the data frame of type C with baseband coding using VHDL. The data frame is encoded based on Miller code and FM0. We showed the implementation results with waveforms. The data frame was proved that it is properly implemented by the experiment of transmission and receiving operation.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.118-119
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• 2007

TWO-CHANNEL방식의 디지털 광센서는 I2C의 출력을 가지고 있다. 하나의 CMOS집적회로에 포토다이오드와 기존의 아날로그-디지털 변환기(ADC)로 구성되어 있었던 방식과는 달리 2개의 비교기(Comparotor)로 2개의 채널을 형성하게 된다. 인간의 눈과 비슷한 반응을 얻기 위해 16-bit의 유효 범위를 갖는다. 이 광센서는 광원의 넓은 파장에 적합하게 설계 되었다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.4
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• pp.490-500
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• 1996

The conventional method to deal with current transformer (CT) Saturation is over dimensioning of the core so that CTs can carry up to 20 times the rated current without exceeding 10% ratio correction. However, this not only reduces the sensitivity of relays as some errors may still be present in the secondary current when a severe fault occurs, but also increases the CT size. This paper presents an algorithm for compensating the distorted secondary current of iron-cored CTs under CT saturation using the magnetization (flux-current : .lambda.-i) curve and its performance is examined for fault currents encountered on a typical 345[kV] Korean transmission system, under a variety of different system and fault conditions. In addition, the results of hardware implementation of the algorithm using a TMS320C10 digital signal processor are also presented. The proposed algorithm can improve the sensitivity of relays to low level internal faults, maximize the stability of relays for external faults, and reduce the required CT core cross-section significantly. (author). refs., figs.

• IE interfaces
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• v.12 no.4
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• pp.575-585
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• 1999

This study develops and operating software for a model plant. The model plant consists of an AS/RS system, two machining centers, an assembly line, and supplementary material handling equipments. Devices of each component are connected with the IBS RT24 DIO 16/16-T I/O module. Each I/O module communicates digital signals with the INTERBUS controller board via SUB-D 9 Connector cable. This study is a previous stage for developing an educational CIM software. Petri Nets is used for modelling the storage/retrieval of the AS/RS system, the flow of workpieces and the assembly line for parts. The operating software is coded with Microsoft Visual $C^{++}$ 5.0 and Interbus Library which is a software driver for the controller board. The operating software can be run on a MS Windows 95. Microsoft Access is used for the implementation of databases for BOM, AS/RS, and parts.