• The Journal of Korean Society for Radiation Therapy
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• v.7 no.1
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• pp.97-102
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• 1995

• Analytical Science and Technology
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• v.11 no.2
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• pp.96-104
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• 1998

A photodiode array multichannel detector system for capillary electrophoresis was developed. The photodiode array detector for capillary electrophoresis (CE-PDA) has 1024 photodetectors and can analyze sample by measuring UV/VIS absorption spectrum in 275~675 nm wavelength range. The CE-PDA instrument can get a spectrum in 30 ms during sample separation and can be programmed by a PC to control various experimental conditions required for sample analysis. The performance of the multichannel CE-PDA instrument was tested using L-ascorbic acid and alizarin yellow GG mixture. The reproducibility test of the CE-PDA system showed 5.6% RSD.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11C
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• pp.1564-1572
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• 2004

UWB(Ultra Wide Band) under standardization for WPAN has a restriction in transmitting power because of interference with existing systems. To overcome the restriction, in this paper, we construct the MIMO(Multi-input-Multi-Output) channel using multi-transmit/receiver antennas and analyze the performance of the proposed system. In addition, through numerical simulation, we obtain the interference property among these antennas and analyze the effect of an interference to the system. The proposed UWB system has a ML detector and the least square method will be used to cancel the multi-user interference and the inter symbol interference caused by multipath.

• Journal of Sensor Science and Technology
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• v.21 no.6
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• pp.402-407
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• 2012

We report a Fabry-Perot interferometer (FPI)-based multi-channel micro-spectrometer used for multi-gas measurement in the spectral range of $3-5{\mu}m$ and its gas sensing performance. The fabricated infrared (IR) spectrometer consists of two parts: an FPI on the top side for selective IR filtering and a $V_2O_5$-based IR detector array on the bottom side for the detection of the filtered IR. Experimental results show that the FPI-based multi-channel gas sensor has reliability and selectivity for simultaneously detecting environmentally harmful gases such as $CH_4$, $CO_2$, $N_2O$ and CO in the spectral range of $3-5{\mu}m$. The fabricated FPI-based multi-channel gas sensor also demonstrated that a reliable and selective detection of gas concentrations ranging from 0 to 500 ppm is feasible. In addition, the electrical characteristics demonstrate a superior response performance in regards to the selectivity in the multi-target gases.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.468-470
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• 2002

We have designed X-ray detection system and multi-channel data acquisition system for Spiral CT application. X-ray detection system consists of scintillator and photodiode. Scintillator converts X-ray into visible light. Photodiode converts visible light into electrical signal. The multi-channel data acquisition system consists of analog, digital, master and backplane board. Analog board detects electrical signal and amplifies signal by 140dB. Digital board consists of MUX(Multiplex) which routes multi-channel analog signal to preamplifier, and ADC(Analog to Digital Converter) which converts analog signal into digital signal. Master board supplies the synchronized clock and transmits the digital data to image reconstructor. Backplane provides electrical power, analog output and clock signal. The system converts the projected X-ray signal over the detector array with large gain, samples the data in each channel sequentially, and the sampled data are transmitted to host computer in a given time frame. To meet the timing limitation, this system is very flexible since it is implemented by FPGA(Field Programmable Gate Array). This system must have a high-speed operation with low noise and high SNR(signal to noise ratio), wide dynamic range to get a high resolution image.

• The Transactions of the Korea Information Processing Society
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• v.7 no.10
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• pp.3218-3225
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• 2000

In this paper, the performance of the MMSE multiauser deteclor was analyzed with the SNR from the standpoint of the exproient, according to the multiuser, In was analyzed not only at the AWGN channel, but at the fading channel also. With the result of this test, the MMSE multiuser detector showed better performance of multi-connection interference in comparison with comon deterctors. However, its disadvantageis that the hardware turns out to be too complicated and that it requires too many calculations. Because of multi-connectioninterference that happens as a result of spreading code horizontally, the DS/CDMA system, which contatins the same frequency and time, turns out to thve interference according to the quality of the call and the number of users. In order to solve these problems, an adaptive MMSE multiuser detector is suggested. To increase the system's processing gain, the hardware's complexity can be reduced by establishing the number of taps wirhin the detector.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1540-1547
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• 2000

In this paper, the performance of the MMSE multiuser detector is compared with the conventional detector with respect to the signal-to-noise ratio, the number of users and the Nakagami parameter under AWGN as well as Nakagami fading channel. The results show that the MMSE multiuser detector is superior to the conventional detector with respect to cancelling the multiple access interference. However, its drawback is the hardware's complexity. To solve this drawback, the advanced MMSE multiuser detector is presented, and its performance is analyzed. The number of taps in the advanced MMSE multiuser are independent of the processing gain. Thus, the system engineer can choose the appropriate number of taps in the detector to achieve a optimal trade-off between the hardware complexity and the performance of system.

• Journal of the Korean Society of Safety
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• v.23 no.3
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• pp.1-7
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• 2008

As a clean fuel, LNG or LPG is widely used in large restaurants or plants instead of coal. These fuels are easy to use and cheap. However, they are inflammable very much and easily exploded at the worst. So there are many laws and regulations legislated for the handling and usage of the gas facilities. Nevertheless, very harsh explosions occurred in several domestic or foreign places. In this paper a gas detection and alarm system was developed for large facilities. A new concept for connecting many gas detectors was proposed and based upon that a system including hardware and software have been developed and tested. Although up to 16 gas detectors apart 1 km from main controller can be connected currently, this system can be easily expanded for more detectors because each gas detector receiver communicates with main controller using industrial standard RS-485 multi drop technique. Furthermore several additive functions was included for the installation and maintenance convenience.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.17-20
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• 2001

This paper studies the channel estimation schemes of Time Division Duplex (TDD) Code Division Multiple Access (CDMA) system with a parallel interference cancellation (PIC) scheme in the multi-Path fading channel. Also, the effective interpolation scheme which maintains the merits of WCDMA TDD mode is proposed. By Monte Carlo simulations, it is shown that the proposed interpolation method can be used in order to obtain the proper performance of a multi-stage PIC and in order to reduce the required Eb/No in the second stage at a BER= 10$^{-2}$

• Nuclear Engineering and Technology
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• v.35 no.4
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• pp.347-355
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• 2003

The \gamma-ray spectrometer of the PGAA (Prompt Gamma Activation Analysis) facility constructed at HANARO of the Korea Atomic Energy Research Institute was upgraded to the multi-mode spectrometer including the single mode, the Compton suppression mode and the pair mode. The performance of the spectrometer was tested and summarized. The background count rate and the uncertainty of the detection efficiency were reduced greatly in comparison with those before the new installation.