• Proceedings of the Korean Nuclear Society Conference
• /
• 1998.05b
• /
• pp.589-593
• /
• 1998

활성탄 검출기를 이용하여 실내 라돈농도를 측정하였다. 라돈농도 측정을 위한 활성탄 검출기의 노출기간은 4일, 5.8일, 5일이었다. 측정결과 사무실내 라돈농도는 각각 1.63 pCi/$\ell$, 1.23 pCi/$\ell$, 1.76 pCi/$\ell$였으며, 측정기간 동안 평균 1.54 pCi/$\ell$였다. 이 결과는 미국 환경보호청에서 제시한 조치준위의 최저치인 4 pCi/$\ell$ 이하였다. 같은 장소에서 WL Meter를 이용하여 라돈 딸핵종의 농도를 축정한 결과, 각각 5. 64 mWL, 4.88 mWL, 6.43 mWL이었다. 라돈과 라돈 딸핵종 농도로부터 라돈평형인자 값을 산출한 결과 각각 0.34, 0.39, 0.36으로, 이 결과는 다른 방법에 의해 타 연구자가 측정한 기존의 사무실내 라돈농도 및 라돈평형인자 산출결과와 비교적 유사했다. 따라서 활성탄 검출기를 이용한 라돈농도 측정법은 매우 유용한 방법임을 확인할 수 있었다.

• Proceedings of the Acoustical Society of Korea Conference
• /
• spring
• /
• pp.163-166
• /
• 2002

본 논문에서는 ETRI 방송 뉴스 자막 처리 시스템의 성능 향상을 도모하기 위해 개발된 미등록어 검출기에 대해 기술한다. 음성 인식 성능 하락에 큰 영향을 미치는 요인들 중 하나로 꼽히는 미등록어 문제를 해결하기 위해 ETRI 방송 뉴스 자막 처리 시스템에서는 오프라인으로 동작하는 미등록어 검출기를 채택하였다. 이 미등록어 검출기는 방송 뉴스 자막 처리 시스템 가동 전에 미리 인터넷을 통해 최신 신문 기사와 방송 뉴스를 수집해와 이를 토대로 두 단계에 걸쳐 미등록어를 사전에 추출하여 인식 어휘 사전에 포함시킴으로써 미등록어로 인한 방송 뉴스의 인식 성능 저하 문제를 해결하도록 하였다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2015.10a
• /
• pp.1571-1572
• /
• 2015

본 논문에서는 GMM (Gaussian mixture model) 기반의 BS (background subtraction) 알고리즘을 이용한 이동 객체 검출기의 하드웨어 구조 설계 결과를 제시하였다. 설계된 이동객체 검출기는 1280 * 720 HD 해상도의 영상을 30 frames per second로 실시간 처리가 가능하다. 하드웨어 구현은 Verilog-HDL을 이용하였으며, FPGA 기반 구현 결과, 설계된 이동 객체 검출기는 582 Slice, 1,698 Slice LUT, 8 DSP48s, 1,769 Flip Flop, 691.2 KByte BRAM으로 구성되었음을 확인하였다.

• The Journal of the Korea Contents Association
• /
• v.13 no.10
• /
• pp.54-61
• /
• 2013

This paper presents a simplified hardware based edge detection circuit which is based on an analog correlator combining with the neighbor pixels in CMOS image sensor. A pixel element of the edge detector consists of an active pixel sensor and an analog correlator circuit which connects two neighbor pixels. The edge detector shares a comparator on each column that the comparator decides an edge of the target pixel with an adjustable reference voltage. The circuit detects image edge from CIS directly that reduces area and power consumption 4 times and 20%, respectively, compared with the previous works. And also it has advantage to regulate sensitivity of the edge detection because the threshold value is able to control externally. The fabricated chip has 34% of fill factor and 0.9 ${\mu}W$ of power per a pixel under 0.18 ${\mu}m$ CMOS technology.

• 대한방사선방어학회:학술대회논문집
• /
• 2009.11a
• /
• pp.184-185
• /
• 2009

• 대한방사선방어학회:학술대회논문집
• /
• 2010.04a
• /
• pp.184-185
• /
• 2010

• 대한방사선방어학회:학술대회논문집
• /
• 2010.04a
• /
• pp.78-79
• /
• 2010

• Journal of the Korean Society of Radiology
• /
• v.11 no.4
• /
• pp.183-188
• /
• 2017

In recent years, the automatic remote control controller of the gamma ray irradiator malfunctions, and radiation workers are continuously exposed to radiation exposure accidents. In the non-destructive testing field, much time and resources are invested in establishing a radioactive source monitoring system in order to prevent potential incidents of radiation. In this study, the gamma-ray response properties of the lead monoxide-based radiation detector were estimated through monte carlo simulation as a previous study for the development of a radioactive source location monitoring system that can be applied universally to various non-destructive testing equipment. As a result of the study, the optimized thickness of the radiation detector varies according to the gamma-ray energy emitted from the radioactive source, and the optimized thickness gradually increases with increasing energy. In conclusion, the optimized thickness of the lead monoxide-based radiation detector was $200{\mu}m$ for the Ir-192, $150{\mu}m$ for the Se-75 and $300{\mu}m$ for the Co-60. Based on these results, the appropriate thickness of lead monoxide-based radiation detector considering secondary-electron equilibrium was evaluated to be $300{\mu}m$ for general application. These results can be used as a basic data for determining the appropriate thickness required in the radiation detector when developing a radiation source location monitoring system for universal application to various non-destructive testing equipment in the future.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.3C
• /
• pp.336-342
• /
• 2003

Noise predictive maximum likelihood(NPML) detector embeds noise prediction/whitening process in branch metric calculation of Viterbi detector and improves the reliability of branch metric computation. Therefore, PRML detector with a noise predictor achieves some performance improvement and has an advantage of low complexity. This thesis random sequences are applied to linear channel. In perpendicular magnetic recording density KP=2.5, NP(121)ML and NP(1221)ML detection system which is based on a noise predictive PR-equalized signal are evaluated by the Performance through a computing simulation. Therefore, NPML systems are implemented and are verified by VHDL.

• Journal of the Korean Society of Radiology
• /
• v.13 no.6
• /
• pp.831-840
• /
• 2019

The X-ray detector by liquid crystal with front light was proposed and verified by a X-ray image. The proposed detector utilizes the visible light instead of the electric signal by transistor. Therefore, it shows low noise and can be fabricated at low cost. The liquid crystal detector uses the orientation change of the liquid crystal molecule by conductivity change of the photoconductive layer. We can get the X-ray image from the transmitted light through the liquid crystal. The X-ray dose was calibrated from the measured transmittance of the visible light after comparison to the reference transmittance curve of the liquid crystal. The amorphous Se was used for photo con ducting layer and parylene was used for the liquid crystal alignment instead of the conventional alignment layer which needs high-temperature process over 200℃. The proposed X-ray detector can decrease the X-ray dose by high sensitivity which was verified by simulation. After the fabrication of the X-ray detector, the X-ray image was obtained as a function of the bias voltage to the liquid crystal. 10 lines/mm resolution was obtained from the line pattern and we will apply it to the 17inch diagonal liquid crystal X-ray detector with 3π retardation.