• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1189-1192
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• 2003

본 논문에서는 노이즈를 고려한 PLL를 설계하였다. 30Mhz∼300Mhz으로 동작하는 VCO를 설계하였다. VCO를 평균 250Mhz으로 동작하도록 하고 reference 주파수, 62.5Mhz로 locking하는 PLL를 설계를 하였다. 300Mhz PLL의 기본적인 구조로 PLL은 PFD(Phase frequency detector), CP(Charge Pump), LF(Loop filter), VCO(Voltage controlled Oscillator)와 Divider로 구성되었다. PFD과 CP는 Dead Zone를 줄이고, 큰 gm를 가지도록 설계를 하였다. PLL에서 가장 중요한 블락인, VCO는 One Chip으로 설계하기 위해 Ring Oscillator로 설계를 하였다. 2.5V 62.5MHZ의 외부 신호를 300MHZ을 발진하는 VCO에서 분주하여 clock synthesizer를 설계하였다. 본 논문은 Hynix0.25공정을 사용하여 설계를 하였으며, 2.5V의 공급 전원을 사용하였다.

• 한국초전도학회:학술대회논문집
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• 2007.07a
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• pp.31-31
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• 2007

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.464-467
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• 2007

All image data acquisition systems for example the digital camera and digital camcorder, use the image sensor to convert the image data (light) into electronic data. These image sensors are used in satellite camera for high quality and resolution image data. There are two kinds of image sensors, the one is the CCD (charge coupled device) detector sensor and the other is the CMOS (complementary metal-oxide semiconductor) image sensor. The CCD sensor control system has more complex than the CMOS sensor control system. For the high quality image data on CCD sensor, the precise timing control signal and the several voltage sources are needed in the control system. In this paper, the comparison of the CCD with CMOS sensor, the CCD sensor characteristic, and the control system will be described.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.391-392
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• 2006

In x-ray imaging system, twokinds of noises are involved. First, the charge generated from the radiation interaction with the detector during exposure is modeled by Poisson process. Second, the signal is then added by readout electronics noise, which is modeled by Gaussian distribution. In this paper, we applied Wiener filter and Wavelet to remove noise from medical X-ray image, the result shows that wavelet yield better segmentation results than the wiener filter.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.197-198
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• 2007

In this paper, a 10Gbps Clock and Data Recovery circuit is designed in $0.18{\mu}m$ CMOS Technology. The circuit incorporates a multiphase LC oscillator, a quarter-rate Bang-Bang phase detector, a Charge Pump and a second order loop filter. The simulation results show that the designed circuit has a peak-to-peak clock jitter of 4.1ps and a peak-to-peak recovered data jitter of 8ps while consuming about 44mW from a 1.8V supply.

• Journal of Information Processing Systems
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• v.1 no.1 s.1
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• pp.27-31
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• 2005

Vehicle detector system based on image processing technology is a significant domain of ITS (Intelligent Transportation System) applications due to its advantages such as low installation cost and it does not obstruct traffic during the installation of vehicle detection systems on the road[1]. In this paper, we propose architecture for vehicle detection by using image processing. The architecture consists of two main parts such as an image processing part, using high speed FPGA, decision and calculation part using CPU. The CPU part takes care of total system control and synthetic decision of vehicle detection. The FPGA part assumes charge of input and output image using video encoder and decoder, image classification and image memory control.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.2
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• pp.169-173
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• 2009

We studied driving characteristics according to the ratio of mass and charging (m/q) value for charged toner particles with black and yellow color in charged particle type display panel. After biasing rectangle pulse to the transparency electrodes of putted panel with toner particles, its response time and contrast ratio are simultaneously measured using a laser as a optical source, photodiode as a detector and reflective system. As a results, contrast ratio is largest at the shortest response time region which is different to the particle because of m/q. We proposed relational equation for response time, m/q, cell gap and biasing voltage. It has not been studied and reported to analyze the relationship of response time, biasing voltage, lumping phenomena, cell gap, and contrast ratio for toner particle type display.

• Journal of Radiation Protection and Research
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• v.39 no.3
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• pp.150-158
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• 2014

Radiation-related practitioners and radiation-treated patients at medical institutions are inevitably exposed to radiation for diagnosis and treatment. Although standards for maximum doses are recommended by the International Commission on Radiological Protection (ICPR) and the International Atomic Energy Agency (IAEA), more direct and available measurement and analytical methods are necessary for optimal exposure management for potential exposure subjects such as practitioners and patients. Thus, in this study we developed a system for real-time radiation monitoring at a distance that works with existing portable device. The monitoring system comprises three parts for detection, imaging, and transmission. For miniaturization of the detection part, a scintillation detector was designed based on a silicon photomultiplier (SiPM). The imaging part uses a wireless charge-coupled device (CCD) camera module along with the detection part to transmit a radiation image and measured data through the transmission part using a Bluetooth-enabled portable device. To evaluate the performance of the developed system, diagnostic X-ray generators and sources of $^{137}Cs$, $^{22}Na$, $^{60}Co$, $^{204}Tl$, and $^{90}Sr$ were used. We checked the results for reactivity to gamma, beta, and X-ray radiation and determined that the error range in the response linearity is less than 3% with regard to radiation strength and in the detection accuracy evaluation with regard to measured distance using MCNPX Code. We hope that the results of this study will contribute to cost savings for radiation detection system configuration and to individual exposure management.

• Journal of Electrical Engineering and Technology
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• v.8 no.5
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• pp.1175-1181
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• 2013

The aim of this paper is to design and evaluate a high concentration, high penetration unipolar corona ionizer. The electrostatic characteristics in terms of voltage-current relationships of the present ionizer in the discharge zones for positive and negative coronas were discussed. Using ion current measurement, the concentration and penetration of ions were evaluated at corona voltages across the needle electrodes between 1 and 4 kV, flow rates between 1 and 5 L/min, and an operating pressure of 1 atm. In the discharge zone of the ionizer, the highest ion concentrations were found to be about $1.71{\times}10^{14}$ and $5.09{\times}10^{14}\;ions/m^3$ for positive and negative coronas, respectively. At the outlet of the ionizer, it was found that the highest ion concentration was about $1.95{\times}10^{13}$ and $1.91{\times}10^{13}\;ions/m^3$ for positive and negative coronas, respectively. The highest ion penetration for positive and negative coronas through the ionizer was found to be about 98 % and 33 %, respectively. The $N_it$ product for positive and negative coronas was also found to $1.28{\times}10^{13}$ and $7.43{\times}10^{13}\;ions/m^3s$, respectively. From the findings, this ionizer proved to be particularly useful as an aerosol charger for positive and negative charge before the detector in an electrical aerosol detector.

• Progress in Medical Physics
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• v.2 no.2
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• pp.129-139
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• 1991

The method of etching tracks in PN-3 dosimeter has been applied to tracks of recoil protons from a neutron source. Both the etch and the detection response of PN-3 has been studied as a function of etched-track diameters against various parameters. We could obtain very useful informations about charge, energy, and mass of particles and the relationship between the track etching rate and the track forming procedure in order to analyze the particle recorded in the solid state track detector. The best etching condition could be found by means of changing the etching circumstances for various energies and particles in order to detect the charged particle accurately. It could be influenced widely that the polymer plastic detector could develep the detecting technique for the low energy level neutron and could be used as a neutron dosimeter in the radiation field such as the nuclear power station, the medical institute and the nondtructive testing institute.