• Journal of Radiation Protection and Research
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• v.34 no.2
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• pp.69-75
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• 2009

To obtain precise information about characteristics of gamma ray detector system responses, we developed new GUI computer program to analize full-energy absorption peak using our developed Delphi computer code for educational purpose. By use of the well known 4 nonlinear peak shaping functions, peaks were fitted with least square fit method in this code. In this paper, we described the methods to search for 12 coefficients in above 4 nonlinear peak shaping functions by use of our developed code in details. The computer code was tested for 1 $\mu$Ci $^{137)Cs$ 661 keV gamma ray peak spectrum detected by 25 % relative efficiency HPGe detector with 5.35 cm (D) $\times$ 5.5 cm (L) size.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.175-184
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• 2023

Based on the actual shape of the detector and the data provided by the manufacturer, the shape of the detector was implemented through Penelope simulation and applied to the appropriate four-layer thickness based on the efficiency obtained from the measurements. Efficiency calculations to determine the effect of the simulated number of Full Energy Peak Efficiency(FEPE) channels in the detector and the outside contact layer in the crystal on the Full Energy Peak Efficiency were performed for various four-layer thicknesses of 0.3, 0.5, 0.7, 1.0, 1.2, and 1.4 mm using the Penelope Code. When the thickness of the external contact layer was increased by 5 times, the Full Energy Peak Efficiency decreased by about 36% for 59.50 keV, and the Full Energy Peak Efficiency decreased by 10% for 1836. In addition, as it increased by 10 times, the Full Energy Peak Efficiency decreased by about 20% for 59.54 keV, and 7% for 1836.01 keV. The Penelope simulated Full Energy Peak Efficiency channel decreases exponentially with the increase in the four layers. In addition, it was confirmed that the total effect curve was well matched with a relative difference of less than 3.5% in the 0.3-1.4 mm dead layer thickness region. However, it was found that the inhomogeneous dead layer is still a parameter in the Monte Carlo model.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.651-658
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• 2017

There were many studies on the development of radiation measuring instruments to detect the presence of radiation. In particular, the signal processing method and treatment without loss of the detection signal are very important. The common feature for these studies is the peak-hold method that keeps the peak value of input signal uniform for a short time, readouts its value, discharges electrical value, and then waits for next signal. We propose the new methodology to capture the pulse peak value from the radiation detector and read the value directly other than peak-hold method. This method has merit of accurate reading the input signal pulse peak value without complicate process of holding for a period or initializing of input signal, and then be verified to be adequate through simulation of actual example.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.37.5-38
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• 2010

경희대학교 우주탐사학과에서는 우주공간 탐사를 위해 Trio(TRiplet Ionospheric Observatory)-CINEMA(Cubesat for Ions, Neutrals, Electrons and MAgnetic fields)로 명명된 초소형 위성을 개발하고 있다. 과학임무는 지구 저궤도에서 고에너지 입자를 관측하는 것이며, 이를 위해 고에너지 (2~300keV) 입자 검출기와 자기장 측정기가 탑재된다. 저에너지 입자 검출기 시스템인 STEIN(SupraThermal Electrons, Ions, Neutrals)은 $1\times4$ Array의 개선된 실리콘 검출기와 이온, 전자, 중성입자를 분리할 수 있는 정전장 편향기, 그리고 신호를 처리하는 전자회로로 구성되어있다. 설계된 전자회로는 매우 작은 검출기 기판, 아날로그 기판과 디지털 기판으로 이루어져 있고, 475mW 이하의 저 전력으로 동작한다. 또한 2~100keV의 에너지를 1keV이하의 해상도로 30,000event/sec/pixel 까지 관측 할 수 있도록 회로를 설계하였다. 센서로 들어온 입자로 인해 발생한 펄스의 신호는 4개의 아날로그 회로가 담당하게 되는데, Folded cascode amplifier를 배치하여 증폭률을 높인 Charge sensitive amplifier를 통해 신호를 증폭하고, $2{\mu}s$ unipolar gaussian shaping amplifier를 통해 읽기 쉽게 처리된 신호를 상한파고선별기와 하한파고 선별기를 통해 유효 값 여부를 판단하고, 피크 검출기를 통해 피크의 타이밍을 측정한 뒤 신호를 아날로그-디지털 변환 회로를 통하여 8bit의 값으로 나타내어, 입자들의 Spectrum을 측정하게 된다. 크기와 소비전력이 적음에도 검출성능이 우수하기 때문에 이 시스템은 향후 우주탐사 시스템에 있어 매우 중요한 역할을 수행 할 것으로 생각한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.1
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• pp.47-54
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• 2019

An improved method of spectrum detection algorithm for mass spectrum analysis system is proposed. In the conventional spectrum detection algorithm that utilizes the results of the linear approximation and quadratic curve fitting on the ion signal block of each mass index, it is possible to reduce the detection error in the mass spectrum detection by further improving the condition of eliminating the invalid ion signals. Also, the proposed method can reduce the estimation error of the peak value of the mass spectrum by using the result of quadratic curve fitting for the effective ion signal block in which the peak position error is corrected. To evaluate the effectiveness of the proposed method, computer simulations were carried out step by step using the measured ion signal. Also, by comparing the rate of false detection for several inputs, the proposed method showed better detection performance than the conventional method.

• Proceedings of the Korean Nuclear Society Conference
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• 2003.05a
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• pp.362.1-362.1
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• 2003

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.141-148
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• 2003

This paper presents and compares several techniques that detect the symbol rate of unknown received signal. Symbol rate is detected from the power spectral density of the circuits such as the delay and multiplier circuit, the square law circuit, and analytic signal, etc. As a result of discrete Fourier transform of the output signals of these circuits, a lot of spectral lines and some peaks appear in frequency domain and the position of first peak is corresponding to the symbol rate. If a spectral line on the frequency that is not located in symbol rate is larger than the first peak, the symbol rate is erroneously detected. Thus, the ratio between the value of first peak and the highest side spectral line is used for the measure of the performance of symbol rate detector. For the MPSK modulation, the analytic signal method shows better performance than the delay and multiplier and square law circuits when the received signal power is lager than -20dB. It is also noted that the delay and multiplier circuit is not able to detect the symbol rate for the QAM modulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.417-420
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• 2005

This report shows the new music player's system which could separate music's tempo by analysis Peak level frequency by time from some percussion instruments. After this process, the new music player could classify some fast or slow genre's musics without a user's order, then we should listen to a fast or slow genre's music by a button.

• Journal of Radiation Protection and Research
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• v.34 no.4
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• pp.190-194
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• 2009

Gamma spectral results for macroalgae samples taken from the environment of Ulchin nuclear power plants in Korea (east coast), showed 766 keV peaks, which were identified as $^{95}Nb$ by several research institutes. After the enhancement of liquid radioactive waste disposal facility at Ulchin NPP site, the $^{95}Nb$ amount in the liquid radioactive waste outflow has drastically reduced, but the expected reduction in $^{95}Nb$ specific activity from environmental samples did not actually show up on gamma spectroscopy. Detailed re-investigation revealed that along with 766 keV peak, other peaks (63, 92 and 1001 keV) from $^{234}Th-^{234}mPa$ decay series were also detected on spectroscopy, and that the measured half lives of the four peaks were very close to known half life of $^{234}Th-^{234}mPa$ decay series, which is 24.1 day. The measured gamma yield ratios of 766 keV peak to 1001 peak were very close to known ratio 0.35 for $^{234}mPa$. It is concluded that 766 keV peaks on gamma spectroscopy of Ulchin NPP environmental samples were mainly from $^{234}mPa$, which is one of naturally occurring radionuclides.

• The Journal of the Acoustical Society of Korea
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• v.28 no.8
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• pp.822-831
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• 2009

The porcelain insulators are important devices, that are used to isolate electrically and hold mechanically in the high-voltage power transmission systems. The faults of the insulators induce very serious problems to the power transmission line. In this paper, we introduce techniques for fault detections of insulators by acoustic radiation noises from them. We measured radiation noises from normal state insulators and fault state insulators. The used insulators were two different type porcelain insulators, a cut out switch, two different type line posters, and a lightning arrester. Each results was compared each other in time domain, frequency domain and filter banks' outputs. We found the possibility of detection of insulators' faults and also suggested techniques for fault detections.