• Journal of Korean Society of Steel Construction
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• v.26 no.2
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• pp.119-132
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• 2014

In this paper, a series of numerical analyses were performed to evaluate the flexural resistance of steel plate girder with longitudinally stiffened and slender web. The SM490 steel was adopted for the study and the flexural resistances evaluated from the numerical analysis were compared with those suggested by the AASHTO LRFD and the Eurocode 3 codes, respectively. It was found that the AASHTO LRFD code could considerably underestimate the flexural resistance as the web slenderness becomes smaller. This comes from the fact that current AASHTO LRFD code does not consider a possible increase of slenderness limits for compact and noncompct web, and also an additional effect of web restraint on the rotation of compression flange in longitudinally stiffened web. Therefore, the slenderness limits of web and flange have been newly proposed for the plate girders with longitudinally stiffened web and it is analytically verified that the flexural resistance can be appropriately estimated by applying the proposed slenderness limits to the AASHTO LRFD code.

• Journal of the Korean Solar Energy Society
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• v.38 no.4
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• pp.1-9
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• 2018

PVT modules commonly can be defined as a combination of PV modules and thermal collectors. After absorbing sun light, electricity and hot water can be actually provided to users simultaneously, which dual outputs (electricity and hot water) have drawn academic interest and industrial activities. Additionally, heat exchange between solar cell and flowing water can enhance solar cell efficiency. Because of PVT modules effectiveness, new international markets and commercial products have made. Especially European, facilities and measurement methods are established to evaluate PVT module performance. However, there are no currently appropriate internationally and domestic standards and facilities to test PVT module performance Herein, to test PVT module performance, indoor thermal simulators and fundamental standard study are considered.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3D
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• pp.353-359
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• 2006

Image frame analysis is a conventional way of evaluating loop detector's performance. In image frame analysis, the time to evaluate performance is linearly proportional to the number of evaluated subjects, and the results can be subjective, depending on operator's personal evaluation standards and physical condition. Also, this method is often inferior in accuracy to that provided by the evaluated devices. Therefore, it is critical to develop a portable standard system which has better accuracy and more objectivity in evaluating vehicle detectors. This paper discusses function and reliability of tape-switch detector, which can be a replacement for image frame analysis, for effectively measuring traffic volume, speed, and occupancy.

• Journal of the Korean Institute of Gas
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• v.20 no.5
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• pp.72-81
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• 2016

When the coatings of buried steel pipelines are damaged, corrosion could be occurred on the surface of the damaged areas. Moreover the pinhole occurred by corrosion of pipelines may cause accidents due to gas leakage. To prevent these accidents, foreign countries including UK and USA have carried out coating defect detection on the buried gas pipelines by using a DCVG or a ACVG and have conducted direct assessment of pipelines through digging the ground, and if necessary, have repaired the pipelines. That is called ECDA i.e External Corrosion Direct Assessment which is regulated by NACE standards(SP 0502) and etc. In Korea, the ECDA provisions were included in KGS FS551 in 2014 when the regulations of Safety Validation in Detail for the medium-pressure piping were introduced. We have developed the equipment which can be used to detect external corrosion of the buried gas pipelines. We have also constructed pipeline test bed for empirical test of the developed equipment. In addition, we have carried out the verification experiments of the developed equipment on the test bed to demonstrate the performance of the equipment. The experiments were conducted by comparison tests of the developed equipment and other equipments which have been introduced and used in Korea. As the result, we have found the developed equipment is easier to use and has far superior performance compared to other equipment being used in Korea.

• International Journal of Highway Engineering
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• v.5 no.1 s.15
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• pp.11-18
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• 2003

Road roughness, as the key factor influencing not only drivers' ride quality and safety but also pavement deterioration, is one of the most important pavement performance indicator to be evaluated by users' subjective assessment. For this reason, a specific number of the pavement roughness has been adopted to monitor the condition of a road for pavement management systems and to evaluate the quality of newly constructed sections, however, none of the unified methodology was internationally accepted. In Korea highway network, road roughness has been used mainly to evaluate newly placed pavement by using 7.6m CP (California Profile meter) to calculate PrI (Profile Index). But this instrument is manually operated to measure road profiles by traffic closure and their interpretation depends on personal bias. Therefore, problems arisen from the manually operated instrument will be overcome by using the APL (Longitudinal Profile Analyzer) which can be operated in the speed of 80km per hour. A study was conducted to correlate the relation from both concrete and asphalt pavement between IRI (measured by APL) and PrI (measured by 7.6m CP). Test results showed that there was a good correlation between IRI and PrI.

• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.85-104
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• 2002

최근 정부(정보통신부)는 사이버 아파트를 포함하여 초고속 정보통신망을 2005년까지 구축하여 각 가정당 10Mbps의 고속 정보통신서비스를 실현한다는 계획을 발표하고, 초고속 정보통신을 활성화하므로 정보통신 선진국 진입을 위하여 "초고속 정보통신 건물 인증제도"를 발표, 현재 시행하고 있다. (1999.7 제정발표) 그러나 시행 과정에서 아파트 중앙 관리실에 있는 MDF 이후의 광케이블과 기타 공사는 건설회사에서 시공하고 중앙 관리실 MDF 이전의 광케이블 공사와 중앙관리실 LAN시설 등의 공사는 통신 전문업체로 하여금, 입주자 별도 부담금으로 시공하고 있다. (컨소시엄구성) 최근 아파트 분양열기 고조로 건설회사 마다 "초고속 정보통신아파트"인증 1등급이라고 선전 및 분양광고 중인데 실제는 "1등급"이 아니고 "2등급" 또는 "3등급"인 경우가 있어, 정부가 목표하는 각 가정당 10Mbps, 개인당 2Mbps 고속정보통신 서비스는 실현성 문제점이 있다. 정부의 인증심사 기준에 중앙관리실 장비 등에 대한 것은 심사기준에 누락되어 있고 또 사생활 정보보호를 위한 대응기술, 시스템 준비 정도까지 포함하여 종합적으로 평가한 뒤 인증을 부여하여야 한다는 것이 본인의 연구 초점이다. 사이버 아파트란 광통신을 주축으로 영상과 음성, 데이터를 자유 자재로 전송 처리하는 초고속 정보통신망을 이용하는 것으로 LAN 장비를 이용하여 각 세대간 통신은 물론 누구나 인터넷을 사용할 수 있는 기능이 있는 설계된 아파트를 말한다. 사이버 아파트의 네트워크에는 금융, 홈쇼핑, 예약, 지역정보, 관공서, 의료서비스, 레저 생활정보 등 차별화된 콘텐츠 확보가 필요하다. 본 연구의 핵심은 사이버 아파트의 현 실태와 문제점, 정부의 인증심사 기준의 미비점과 문제점, 사이버 아파트의 기능, 구성요소, 시스템 구축, 서버활용도, 장비들에 관한 것과 그리고 정부의 사이버 아파트 육성정책, 정보보호 대책과 관련업체들의 동향 등을 연구하여 요약 정리하였다.

• The Journal of Korean Society for Radiation Therapy
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• v.16 no.2
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• pp.43-61
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• 2004

Purpose : For qualify improvement in radiotherapy, it is important to set up and evaluate equipment (linac) accurately. In addition, technicians are needed to be fully aware of the equipment's detailed quality and its manual. Therefore, the result of ATP is evaluated and introduced, in order that the technicians are skilled by participating in quality assurance (QA) and understanding the quality of the equipment before clinical use. Method and Material : QA for LINAC 21EX (Varian, US) was done with suppliers its procedure was divided into radiation survey, mechanical test, radiation isocenter test, bean performance, dosimetry, and enhanced dynamic wedge and using X-omat film (Kodak), multidata, densitometer, and electrometer. QA of MLC (Millennium, 120 leaf) attached to LINAC and EPID (Portal vision) were done separately. Result : The leakage dose by survey meter was below the tolerance. In mechanical test, collimater, gantry, and couch rotation were less than 1mm, and the angles were ${\pm}0.1^{\circ}$ for digital and ${\pm}0.5^{\circ}$ for mechanical. The alignment test of the light field and crosshair were evaluated less than 1mm. The (a)symmetrical jaw field was less than ${\pm}0.5mm$. The radiation isocenter test using X-mat film was less than 1mm. The consistency of light field and radiation field was less than ${\pm}0.1mm$. PDD for photon energy was less than ${\pm}1\%$ and for electron energy of $90\%,\;80\%,\;50\%,\;and\;30\%$ were evaluated within the tolerance. Flatness for photon and electron energy was evaluated $2.3\%$ (tolerance $3\%$) and $3\%$ (tolerance $4.5\%$), respectively, and symmetry was $0.45\%$ (tolerance $2\%$) and $0.3\%$ (tolerance $2\%$), respectively. Dosimetry test for short term, MU setting, rep rate, and dose rate accuracy of photon and electron energy was within the tolerance depending on energy, MU, and gantry angle. Conclusion : Accuracy and safety for clinical use of Clinac 21EX was verified through customer acceptance procedure and the quality of the equipment was found out. These can reduce the difficulties in using the equipment. Furthermore, it is useful for clinically treatment of patients by technicians' active participations.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11b
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• pp.711-714
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• 2003

인터넷의 발달로 네트워크 업무가 점점 더 많이 도입이 됨으로써 네트워크 상에 노출되어 있는 데이터와 시스템들의 보안은 중대한 문제로 대두되기 시작했다. 그러나 장비나 소프트웨어 등의 보안성과 보안성능 평가에 대한 기준이 명확하지 않아 이들의 객관적인 평가에 많은 어려움이 따르고 있다. 본 논문에서는 관련 연구 기관들의 평가 방법들을 분석하여 이들을 객관적으로 평가 할 수 있는 방법을 제시하고자 한다.

• Journal of the Korean Society of Radiology
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• v.9 no.1
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• pp.61-65
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• 2015

Mammography equipment is an essential detector for making an early diagnosis of female's breast lesion. Recently, in most hospitals, a digital mammography detector is used due to the wide and consistent supply of digital mammography equipment. However, the average effective radiation is increasing due to the indiscreet use of CR or DR mammography. The purpose of this study is to recognize the possible indirect radiation damage, which can be occurred due to an excessive effective exposure of radiation, by evaluating spacial radiation rate of the digital mammography detector used for female patient. Consequently, the high mount of spacial radiation showed digital mammography equipment on the horizontal direction. Considering the result, digital mammography equipment should be installed by avoiding along the horizontal direction.

• Proceedings of the Korean Reliability Society Conference
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• 2011.06a
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• pp.131-140
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• 2011

도로안전시설용 시선유도봉은 통상 도로에 설치되어 운전자의 시선을 유도하고 차선을 분리하는 용도로 사용된다. 이러한 시선유도봉은 주로 도로상에 설치되기 때문에 차량과 부딪히는 경우가 자주 발생하므로 제품의 내구성이 특히 요구된다. 종래의 시선유도봉에 대한 평가방법은 제품의 일부를 채취하여 재료의 기본 품질 성능만을 평가하였다. 그러나 현장의 도로관리를 담당하고 있는 수요기관에서는 빈번한 사고와 민원으로 인해 제품의 평가방법에 대한 문제 제기를 하였고, 완제품 상태로 신뢰성을 평가할 수 있는 방법 개발을 요구하였다. 따라서 본 연구에서는 시선유도봉의 주요 고장 요인이 되는 차량 충돌에 의한 재질 파손, 바퀴 압축에 의한 회복 불능, 제품 표면에 부착되는 반사시트의 박리 및 변색에 대한 고장 메커니즘 분석하고, 이러한 고장을 재현할 수 있는 신뢰성 평가법을 개발하고자 하였다. 주요 고장 메커니즘 분석을 위해 국내.외 평가 기준을 조사하였으며, 특히 미국 AASHTO's (American Association of State Highway and Transportaion Officials)의 NTPEP (National Transportation Products Evaluation Program)에서 수행하고 있는 내구성 평가 방법에 대한 사례 조사를 통해 국내 적용을 검토해 보았다. 또한 서울시설관리공단의 협조로 가장 주요한 고장의 요인으로 꼽히는 차량 충돌 시험을 올림픽대로 내 조각공원에서 실시하였다. 그 결과 시험실에서 고장을 재현할 수 있는 신뢰성 평가 장비 개발의 필요성이 부각되었으며, 차량 충돌과 바퀴 압축을 모사할 수 있는 신뢰성 평가 장비를 제작하였다. 시선유도봉의 신뢰성 평가는 기본적인 품질성능평가 이외에 신규로 개발된 충격시험(고온, 저온, 반사지)과 굴곡압축시험, 반사지와 재질의 내후성 시험을 실시하였다. 또한 국내 9개사(社) 10개 제품에 대한 신뢰성 비교평가를 실시한 결과, 제품의 내구성에 중요 척도가 되는 신뢰성 평가 기준을 설정할 수 있었고, 합리적인 제품의 가격 수준과 품질 수준에 대한 신뢰성 가이드를 제공할 수 있었다.