• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2003년도 하계학술대회
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• pp.382-384
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• 2003

지하 30m 암반에 건설된 통신구 터널의 안전성을 검토하기 위하여 콘크리트 라이닝 두께를 지중레이다(Ground Penetrating Radar)와 충격반향기법(Impact-Echo Method)으로 추정하였다. 지중레이다에 의한 콘크리트 라이닝 단면의 연속적인 화상으로부터 라이닝 두께의 상대적인 변화를 파악하였으며, 라이닝 두께가 얇은 구간은 충격반향 기법에 의해 일정 간격으로 두께를 추정하였다. 터널 천장의 라이닝 두께는 31.85cm, 좌측 및 우측 측벽부의 라이닝 두께는 각각 32.45cm. 32.97cm로서 설계 값인 30cm와 비교적 잘 일치하는 것으로 파악되었다. 지중레이다와 충격반향기법을 조합한 본 방법은 터널 라이닝 콘크리트 두께를 추정하는데 있어서 매우 효율적이고 신뢰성 있는 방법으로 분석되었다.

• 천문학회보
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• 제42권2호
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• pp.65.4-65.4
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• 2017

The laboratory astrophysics is a new emerging field of basic sciences, and has tremendous discovery potentials. The laboratory astrophysics investigates the basic physical phenomena in the astrophysical objects in controlled and reproducible manners, which has become possible only recently due to the newly-established intense photon and ion beam facilities worldwide. In this presentation, we will introduce several promising ideas for laboratory astrophysics programs that might be readily incorporated in the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). For example, precise spectroscopic measurements using Electron Beam Ion Trap (EBIT) and intense X-ray photons from the PAL-XFEL can be performed to explore the fundamental processes in high energy X-ray phenomena in the visible universe. Besides, in many violent astrophysical events, the energy density of matter becomes so high that the traditional plasma physics description becomes inapplicable. Generation of such high-energy density states can be also be achieved by using the intense photon beams available from the PAL-XFEL.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.351-352
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• 2015

Thyristor-controlled series capacitor (TCSC) is a power electronic-based device that provides a fast and controllable series compensation of transmission line reactance. To match with laboratory facilities and for further research initiatives, a practical laboratory scale TCSC was designed and fabricated in this paper. The TCSC parameters were designed based on the terminologies such as percentage of compensation, boost factor and resonance factor. According to the design parameters, a prototype laboratory scale TCSC with a constant reactance controller was fabricated and tested. The measured results from the laboratory scale TCSC demonstrate the ability of the TCSC to provide rapid control of series reactance of a transmission line.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3595-3603
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• 2022

Nuclear safety-class DCS is used for nuclear reactor protection function, which is one of the key facilities to ensure nuclear power plant safety, the maintenance for DCS to keep system in a high reliability is significant. In this paper, Nuclear safety-class DCS system developed by the Nuclear Power Institute of China is investigated, the model of reliability estimation considering nuclear power plant emergency trip control process is carried out using Markov transfer process. According to the System-Subgroup-Module hierarchical iteration calculation, the evolution curve of failure probability is established, and the preventive maintenance optimization strategy is constructed combining reliability numerical calculation and periodic overhaul interval of nuclear power plant, which could provide a quantitative basis for the maintenance decision of DCS system.

• Journal of Radiation Protection and Research
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• 제41권2호
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• pp.123-131
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• 2016

Background: With the increase in the number of particle accelerator facilities under either operation or construction, the accurate calculation using Monte Carlo codes become more important in the shielding design and radiation safety evaluation of accelerator facilities. Materials and Methods: The calculations with different physics models were applied in both of cases: using only physics model and using the mix and match method of MCNPX code. The issued conditions were the interactions of 600 MeV proton and $290MeV{\cdot}n^{-1}$ oxygen with a carbon target. Both of cross-section libraries, JENDL High Energy File 2007 (JENDL/HE-2007) and LA150, were tested in this calculation. In the case of oxygen ion interactions, the calculation results using LAQGSM physics model and JENDL/HE-2007 library were compared with D. Satoh's experimental data. Other Monte Carlo calculations using PHITS and FLUKA codes were also carried out for further benchmarking study. Results and Discussion: It was clearly found that the physics models, especially intra-nuclear cascade model, gave a great effect to determine proton-induced secondary neutron spectrum in MCNPX code. The variety of physics models related to heavy ion interactions did not make big difference on the secondary particle productions. Conclusion: The variations of secondary neutron spectra and particle transports depending on various physics models in MCNPX code were studied and the result of this study can be used for the shielding design and radiation safety evaluation.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.54-57
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• 1998

통신망의 물리적 기반이 광케이블로 대치됨에 따라 광케이블 선로의 품질유지 및 체계적인 관리에 대한 요구도 점차 증대되고 있다. 한국통신은 광케이블 선로의 유지보수 체계를 확립하고 자동화 하기 위하여 광선로 운용 감시 시스템(FLOMS:Fiber Line Operation & Monitor System, 이하 FLOMS라 한다.)을 개발하였다. FLOMS는 광케이블 시설에 대한 체계적인 관리 및 광케이블 선로 특성시험 자동호를 통한 선로의 이상 유무를 체크하고 보고할 수 있다. 광케이블 유지보수 요원은 FLOMS 시스템을 이용하여, 운용센터에서 관리대상 전화국의 광케이블 선로들을 원격시험 할 수 있으며 기존의 광전송장치 운용관리 시스템과 연동함으로써 전송분야 운용관리의 통합관리가 가능하게 되었다. 이 시스템을 적용함으로써 광케이블 선로 고장위치의 신속한 파악에 의한 공장시간 단축, 광케이블 선로 특성의 주기적인 측정에 의한 예방보전, 광케이블 심선 정보의 전산화 관리에 의한 업무효율의 향상을 이룩하였다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2002년도 하계학술대회 및 세미나
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• pp.199-207
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• 2002

A virtual laboratory for measurement and instrumentation must aim to realize an integrated environment. To achieve this goal, we designed and implemented a client/server distributed environment and developed a web-based virtual laboratory system for electronic circuits. Since our virtual laboratory system is implemented to describe the on-campus laboratory, the learners can obtain similar experimental data through it. The proposed virtual laboratory system is composed of four important components Principle Classroom, Virtual Experiment Classroom, Evaluation Classroom and Overall Management System. Through our virtual laboratory, the learners will be capable of teaming the concepts and theories related to electronic circuit experiments and how to operate the experimental equipments such as multimeters, function generators, digital oscilloscopes and DC power supplies. Also, every activity occurred in our virtual laboratory is recorded on database and Printed out on the preliminary report form. All of these can be achieved by the aid of the Management System. The database connectivity is made by PHP and the virtual laboratory environment is set up slightly differently for each learner. Finally, we have obtained several affirmative effects such as reducing the total experimental hours and the damage rate for experimental equipments and increasing Loaming efficiencies as well as faculty productivity.

• 한국화재소방학회논문지
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• 제26권6호
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• pp.15-23
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• 2012

$CO_2$ 소화설비의 소화성능 시험방법에는 직접시험방법이 가장 좋지만, 고비용과 환경문제 그리고 시험절차의 어려움으로 간접시험방법을 사용하는 경우가 많다. 그러나 석유화학플랜트나 원자력발전소와 같은 국가 중요위험시설은 화재가 발생하면 대형피해가 발생할 수 있으므로 직접방사시험을 통해 소화성능을 검증할 필요가 있다. 본 연구는 국가 중요위험시설에 설치된 전역방출방식의 $CO_2$ 소화설비 중에서 표면화재 방호구역과 심부화재 방호구역을 각각 선정하여 $CO_2$ 소화설비의 소화성능을 검증해 보았다. 소화성능은 방호구역 내에 방사된 $CO_2$의 농도가 설계농도기준(NFSC 및 NFPA)에 만족해야 그 성능을 인정받을 수 있다. 여기서, 설계농도는 $CO_2$ 소화약제가 화염을 제어할 수 있는 소화농도에 여유율 20 %를 감안한 농도를 의미한다. 시험결과 표면화재와 심부화재 방호구역 모두 $CO_2$ 설계농도를 확보하고 있음을 확인하였고 심부화재의 경우에는 20분 이상 설계농도가 유지되었다. 본 연구를 통해 국가 중요위험시설에 대한 직접방사시험 방법 및 판정방법을 소개하였고 향후 이와 같은 국가 중요위험시설에는 직접방사시험을 통해 소화설비의 신뢰성을 검증해야 할 필요성을 제기하였다.

• Journal of Radiation Protection and Research
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• 제46권1호
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• pp.1-7
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• 2021

Background: The use of computed tomography (CT) device has increased in the past few decades in Japan. Dose optimization is strongly required in pediatric CT examinations, since there is concern that an unreasonably excessive medical radiation exposure might increase the risk of brain cancer and leukemia. To accelerate the process of dose optimization, continual assessment of the dose levels in actual hospitals and medical facilities is necessary. This study presents organ dose estimation using pediatric cerebral CT scans in the Kyushu region, Japan in 2012 and the web-based calculator, WAZA-ARI (https://waza-ari.nirs.qst.go.jp). Materials and Methods: We collected actual patient information and CT scan parameters from hospitals and medical facilities with more than 200 beds that perform pediatric CT in the Kyushu region, Japan through a questionnaire survey. To estimate the actual organ dose (brain dose, bone marrow dose, thyroid dose, lens dose), we divided the pediatric population into five age groups (0, 1, 5, 10, 15) based on body size, and inputted CT scan parameters into WAZA-ARI. Results and Discussion: Organ doses for each age group were obtained using WAZA-ARI. The brain dose, thyroid dose, and lens dose were the highest in the Age 0 group among the age groups, and the bone marrow and thyroid doses tended to decrease with increasing age groups. All organ doses showed differences among facilities, and this tendency was remarkable in the young group, especially in the Age 0 group. This study confirmed a difference of more than 10-fold in organ doses depending on the facility and CT scan parameters, even when the same CT device was used in the same age group. Conclusion: This study indicated that organ doses varied widely by age group, and also suggested that CT scan parameters are not optimized for children in some hospitals and medical facilities.

• 한국제4기학회:학술대회논문집
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• 한국제4기학회 2003년도 제4기학회 제33차 학술발표대회
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• pp.39-40
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• 2003