• Journal of Radiation Protection and Research
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• 제44권2호
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• pp.72-78
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• 2019

Background: In the calibration and testing laboratory of Korea Atomic Energy Research Institute, the old X-ray generator used for the production of reference X-ray fields was replaced with a new one. For this newly installed X-ray irradiation system, beam alignment as well as the verification of beam qualities was conducted. Materials and Methods: The existing X-ray generator, Phillips MG325, was replaced with YXLON Y.TU 320-D03 in order to generate reference X-ray fields. Theoretical calculations and Monte Carlo simulations were used to determine initial filter thickness. Beam alignment was performed in three steps to deliver a homogeneous radiation dosage to the target at different distances. Finally, the half-value layers were measured for different X-ray fields to verify beam qualities by using an ion chamber. Results and Discussion: Beam alignment was performed in three steps, and collimators and other components were arranged to maintain the uniformity of the mean air kerma rate within ${\pm}2.5%$ at the effective beam diameter of 28 cm. The beam quality was verified by using half-value layer measurement methods specified by American National Standard Institute (ANSI) N13.11-2009 and International Organization for Standardization (ISO)-4037. For each of the nine beams than can be generated by the new X-ray irradiation system, air kerma rates for X-ray fields of different beam qualifies were measured. The results showed that each air kerma rate and homogeneity coefficient of the first and second half-value layers were within ${\pm}5%$ of the recommended values in the standard documents. Conclusion: The results showed that the new X-ray irradiation system provides beam qualities that are as high as moderate beam qualities offered by National Institute of Standards and Technology in ANSI N13.11-2009 and those for narrow-spectrum series of ISO-4037.

• 핵의학기술
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• 제20권1호
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• pp.37-41
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• 2016

정도관리(Quality Control)는 오차를 최소한으로 하여 검사의 신뢰도를 증진 시키는 것을 목적으로 하고 있으며 이러한 정도관리 활동을 통해 환자의 진단과 치료방침에 영향을 주는 핵의학 혈액 검사의 신뢰도가 확보되고 있다. 이에 연구자들은 신뢰도 향상의 추가적인 기법으로 건강검진 수검자를 대상으로 시행한 핵의학 혈액검사의 모집단 분포를 이용한 통계적 품질관리의 유용성을 평가해 보고자 한다. 2014년 1월부터 2014년 12월까지 서울아산병원 건강증진센터를 이용한 건강검진 수검자 41,341명을 대상으로 핵의학 혈액 검사 12종목에 대해 통계 분석을 시행 하였다. 통계분석은 핵의학 혈액 검사 12종목에 대한 결과 보고 치를 참고치 이내, 참고치 이상, 참고치 이하의 세 가지 그룹의 월간 백분율로 구분하여 모집단 분포의 평균값과 표준편차, 그리고 표준편차 지수(Standard Deviation Index: SDI)를 산출 하였고 그 결과 모집단 분포의 표준편차는 모든 그룹에서 대부분 ${\pm}2SD$ 이내의 결과를 보였다. 건강검진 수검자에 대한 핵의학 혈액검사 12종목(AFP, CEA, CA19-9, CA125, PSA, TSH, FT4, Anti-Tg-Ab, Anti-TPO-Ab, Calcitonin, 25-OH-VitD3, Insulin)의 모집단 분포를 분석한 결과 월간 백분율의 표준편차 지수(SDI)가 ${\pm}2.0$ 이상인 경우는, 1월과 3월 Insulin검사에서 각각 2.3, 2.4, 5월 Anti-Tg-Ab검사에서 2.2, 그리고 9월 CA19-9에서 2.2의 결과를 보였다. 이는 검사 Kit 시약의 이상 (동위원소 시약의 최대 결합률 저하), 검사반응 시간의 저하가 원인 이었다. 연구대상이 되는 전체의 속성을 포함하고 모집단 분포의 특성을 이용한 통계적 품질관리는 검사실에서 시행하고 있는 내부정도관리 프로그램을 보완하는 역할을 할 수 있으리라 생각된다.

• 과학과기술
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• 제16권12호통권175호
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• pp.42-44
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• 1983

• 월간산업보건
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• 통권96호
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• pp.5-14
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• 1996

• 한국ITS학회 논문지
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• 제12권3호
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• pp.29-41
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• 2013

본 연구는 교통정보센터와 노변장치간 국제표준 규격인 ISO 15784를 적용하여 국내 환경에 맞는 노변장치와 교통정보센터간 정보교환 표준 개발을 목표로 한다. 이를 위해 ISO 14817과 ISO 14827 Part 1을 참조하여 메시지 교환 시나리오 개념의 메시지 기본 개념과 시스템 구축 호환성 확보를 위해 명확히 정의가 필요한 필수 메시지 정의 항목을 정의하였다. AVI와 교통정보센터간 교환되는 실제 메시지 표준 개발을 위해 ITS 표준 기술위원회에 표준실무팀을 구성하여, ITS 아키텍쳐 정보흐름 분석, 국내 기 표준 분석, 현재 시내부와 국도상에 실제 설치되어 운영되고 있는 AVI 장비 메시지 프로토콜을 비교분석하여 총 14개의 기능 메시지를 정의하고, 이에 대해 DATEX 응용 프로토콜의 메시지 교환 시나리오에 따라 총 28개 메시지를 정의하였다. 데이터 교환을 위한 응용프로토콜은 ISO 15784의 참조표준을 분석하여 국내 현장장비와 교통정보센터간 데이터교환 환경을 고려한 상호운영성 및 상호호환성 확보를 위한 요구사항을 정의하였다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 춘계학술발표회논문집
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• pp.91-96
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• 2004

More recently, multiple reference based RTK GPS techniques(VRS : Virtual Reference System) are becoming increasingly important for many precise GPS applications in many countries to overcome the constrained distance limitations of standard RTK systems. The precision of the position solutions of the rover receiver is closely connected with that of the corresponding virtual reference points(VRPs). The objective of this paper is to investigate the accuracy and performance of the VRPs on the test network for static positioning in post processing mode. For this, some VRPs at the inside and outside of test network have made in post mode, and the overall analysis results were presented by comparing the solution for the VRPs from the existed GPS reference station with the true values of the coordinates used to produce the observation data. The results show the reasonable accuracies of VRPs in the network area by using the VRS concept in post mode.

• International Journal of Control, Automation, and Systems
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• 제4권1호
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• pp.70-76
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• 2006

The objective of this paper is to propose a reference model of a fire detection and monitoring system using MS/TP protocol. The reference model is designed to satisfy the requirements of response time and flexibility. The reference model is operated on the basis of BACnet, a standard communication protocol for building automation systems. Validity of the reference model was examined using a simulation model. This study also evaluated the performance of the BACnet-based fire detection and monitoring system in terms of network-induced delay. Simulation results show that the reference model satisfies the requirements of the fire detection and monitoring system.

• 전자공학회논문지A
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• 제33A권4호
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• pp.136-141
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• 1996

In this paper, a new CMOS on-chip current reference circit for memory, operational amplifiers, comparators, and data converters is proposed. The reference current is almost independent of temeprature and power-supply variations. In the proposed circuit, the current component with a positive temeprature coefficient cancels that with a negative temperature coefficient each other. While conventional curretn and voltage reference circuits require BiCMOS or bipolar process, the presented circuit can be integrated on a single chip with other digiral and analog circits using a standard CMOS process and an extra mask is not needed. The prototype is fabricated employing th esamsung 1.0um p-well double-poly double-metal CMOS process and the chip area is 300um${\times}$135 um. The proposed reference current circuit shows the temperature coefficient of 380 ppm/.deg. C with the temperature changes form 30$^{\circ}C$ to 80$^{\circ}C$, and the output variation of $\pm$ 1.4% with the supply voltage changes from 4.5 V to 5.5 V.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.419-420
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• 2006

In the new video coding standard H.264/AVC, motion estimation (ME) is allowed to search multiple reference frames for improve the rate-distortion performance. The complexity of multi-frame motion estimation increases linearly with the number of used reference frame. However, the distortion gain given by each reference frame varies with the video sequence, and it is not efficient to search through all the candidate frames. In this paper, we propose a fast mult-frame selection method using all zero coefficient block (AZCB) prediction and sum of difference (SAD) of neighbor block. Simulation results show that the speed of the proposed algorithm is up to two times faster than exhaustive search of multiple reference frames with similar quality and bit-rate.

• 전기학회논문지
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• 제58권2호
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• pp.369-372
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• 2009

When measuring the luminous flux of a light source at the integrating sphere photometer, it can know the luminous flux to compare the standard lamp with the specimen lamp at the same location. But in case of PLS(plasma lighting system, microwave discharged lamp), that two lamps are cannot be the same location. If the reference illuminant and specimen lamp are cannot measure identical location, we should measure the variation of the luminous flux. For the outcome we can turn out a correction factor to revise and reflect it. But the better way is calibrate the specimen lamp locate the identical location of reference illuminant measured. In this thesis, we've test to find the correction factor for consider that change the measuring location. And it turns out the correction factor. From this, it presents the result to make a select for the reference illuminant which is against the illuminant type for newly produce.