국제학술회의 참관기 - 제30차 국제지질학 총회 및 학술발표회

정대교,Jeong, Dae-Gyo 한국과학기술단체총연합회 1996 과학과 기술 Vol.29 No.11

지난 8월4일부터 14일까지 중국 북경에서 열린 제30차 국제지질학 총회 및 학술발표회에는 1백여 국가에서 1만여명이 참석하여 성황을 이루었다. 한국에서도 50여명의 지질학자들이 참가한 이번 학술대회에 다녀온 강원대 정대교교수의 참관기를 싣는다.

C . C . A 계 방부제의 철부식성 (鐵腐蝕性) 시험

정대교,한문만 한국목재공학회 1986 목재공학 Vol.14 No.6

This study was a testing about the corrosion of iron caused by wood preservatives. The test blocks used in this experiment were treated with 2% CCA-1, CCA-2, CCA-3, ACC, P. F solution. The test periods were 5 days, 10 days, and 20 days. The test blocks were let into the desiccator filled with K₂SO₄ saturated solution in the bottom, and after the nails were withdrawn, the nails were boiled in a solution of ammonium citrate(10%) for 20 minutes, iron ruse removed and weighed. The results were nrmrnarized as follows ; 1. There were highly significance among the wood preservative treatment on the rate of weight loss of nails in wood. The treatment among CCA-1, ACC and P.F didn't show significant difference, arid no significance between CCA-2 and CCA-3. The treatment of CCA-1 had the greatest rate of weight loss of nails in wood compared to other treatments. 2. The test periods didn't show significant difference, and there were not significant between interaction of the period and preservatives. 3. The wood preservatives of CCA-2 and CCA-3 would be considered the relatively stable wood preservatives among the other waterborne preservatives tested in this study due to the relative lower corrosives.

Comparison of effective dose for imaging of mandible between multi-detector CT and cone-beam CT

정대교,이상철,허경회,이원진,허민석,이삼선,최순철 대한영상치의학회 2012 Imaging Science in Dentistry Vol.42 No.2

Purpose: The aim of this study was to compare the effective dose for imaging of mandible between multi-detector computed tomography (MDCT) and cone-beam computed tomography (CBCT). An MDCT with low dose technique was also compared with them. Materials and Methods: Thermoluminescent dosimeter (TLD) chips were placed at 25 organ sites of an anthropomorphic phantom. The mandible of the phantom was exposed using 2 different types of MDCT units (Somatom Sensation 10 for standard-dose MDCT, Somatom Emotion 6 for low-dose MDCT) and 3 different CBCT units (AZ3000CT, Implagraphy, and Kavo 3D eXaM). The radiation absorbed dose was measured and the effective dose was calculated according to the ICRP 2007 report. Results: The effective dose was the highest for Somatom Sensation 10 (425.84 μSv), followed by AZ3000CT (332.4 μSv), Somatom Emotion 6 (199.38 μSv), and 3D eXaM (111.6 μSv); it was the lowest for Implagraphy (83.09 μSv). The CBCT showed significant variation in dose level with different device. Conclusion: The effective doses of MDCTs were not significantly different from those of CBCTs for imaging of mandible. The effective dose of MDCT could be markedly decreased by using the low-dose technique.

회원작품 - 마일스톤 SG

정대교,Jeong, Daegyo 대한건축사협회 2022 建築士 Vol.637 No.-

KT스마트그리드 구현사례

정대교,김형수,유성민 한국통신학회 2013 정보와 통신 Vol.30 No.2

본고에서는 스마트그리드 사업을 적용하여 현재 세종시 첫마을에 추진하고 있는 스마트그린시티 건설프로젝트 사업에 대하여 다루어 보고자 한다. 행정중심복합도시건설청(행복청) 에서는 2030년까지 세종시의 이산화탄소 70%절감 그리고 세종시의 전체에너지 공급에 약 17% 정도를 그린에너지로 대체를 목표로 하고 있다. 이를 위하여, 우선적으로 행복청은 ICT 기술을 활용한 스마트그리드 기술을 적용하여 에너지 절감 목표를 추진 중에 있다. 행복청은 현재 첫마을 공공 4개 건물을 시범사업으로서 원격통합관리 서비스를 2012년 09월에 구축하기 시작 하였으며, 현재에는 이러한 설비들이 모두 구축된 상태이며 에너지 절감방안을 도출 중에 있다. 본고에서는 지금까지 진행되어 온 세종시 첫마을 원격통합관리 서비스에 대하여 알아보고자 한다.

백악기 풍암 퇴적분지의 생성 진화와 퇴적물 기원

정대교 강원대학교 자원개발연구소 1998 자원개발연구 Vol.13 No.-

Energy Operation Management for Smart City using 3D Building Energy Information Modeling

정대교,박승희,이동환 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

During the last decade, global interest according to energy efficiency and climate change has dramatically increased. In particular,the building sector plays an important role, as it accounts for significant percentages of total energy consumption. So numerous highenergy efficiency devices have been developed and applied to building. But it is also important that such high energy efficiencyequipment is operated through efficient management. In this paper, through establishing a Building Energy Management System(BEMS) in the test-beds, the energy consumption and environmental data are measured and gathered at a total operation center. Theproposed energy saving technologies would integrate real-time energy consumption monitoring with Building Energy InformationModeling (BEIM). To find an optimal energy-saving method, a building energy simulation was used with Genetic Algorithms. TheHeating Ventilating and Air-Conditioning (HVAC) control schedules were sought. The energy-saving effect of this method is about9.44%. HVAC control schedules can be applied to building, using a function to control facilities in buildings. This energy-saving effectwill be added to the general saving effects for BEMS. It is expected that the proposed energy optimization tool using BEIM will beapplied to the micro-energy grid system for smart city in the near future.

참나무류의 용도개발을 위한 비교내후성 연구 : Tyromyces palustris와 Coriojus versiclolor균을 중심으로 By Tyromyces Palustris and Coriolus Versicolor

정대교,민경희 건국대학교 교육대학원 1990 敎育論叢 Vol.13 No.-

This study was carried out to investigate the relative durability of 6 Quercus species. The relative durability of decay was expressed by the percentage of weight loss. The test fungi were Tyromyces palustris and Coriolus versicolor. The results are as follows: 1.Heart wood of Q. dentata and sap wood of Q. variabilis were showed the highest durability for T. palustris and the lowest decay-resistance was heart and sap wood of Q. mongolica for it. 2.For C. versicolor, the durability of heart and sap wood of Q. dentata highest and it of Q. mongolica was showed the lowest without any difference heart wood and sap wood. 3.The weight loss were not showed the significant difference among the samples taken from different height of the tree for all 6 species. The weight loss of all 6 species, however, were significant above 450cm of the trunk expect sapwood of Q, dentata and Q. variabilis for T. palustris. 4.Quercus dentata may be the best decay-resistant by T. palustris and C. versicolor for T. palustris.

FTA기법을 이용한 교육시설 누수 하자 유형 분석 및 주요 원인 관리방안

정대교,박현정,이동엽,김대영,Jung, Daegyo,Park, Hyunjung,Lee, Dongyeop,Kim, Daeyoung 한국건설관리학회 2024 한국건설관리학회 논문집 Vol.25 No.1

최근 건설 산업에서는 스마트 기술을 통해 건축물의 품질 향상과 안전확보에 노력하고 있지만, 여전히 누수 하자는 증가하는 추세이다. 특히 교육 시설에서는 노후화로 인한 하자 발생이 주요 문제로 부각되고 있습니다. 본 연구는 FTA 기법을 사용하여 교육시설 누수 하자 발생의 원인을 분석하고, 이를 바탕으로 예방 대책을 제시하고자 한다. 국내 문헌 조사를 통해 FTA 기법을 설명하고, 2019~2021년 교육지원청 데이터를 분석하여 주요 하자를 식별합니다. 교육시설 누수 하자의 FT 도를 구성한 결과 12개의 기본 사상이 추출되었습니다.이후, FTA 분석을 통해 누수 원인을 자세히 파악하고 주요 하자 원인을 도출하였다. 그 결과, 교육시설 하자 접수 건 중 누수 하자가 46.8%를 차지하며, 옥상층(천정) 누수가 가장 많았으며, FTA 분석 결과 옥상층(천정) 누수의 주요 원인으로는 바탕면 처리 불량으로 나타나며 이는 방수층 균열, 이음부 균열, 방수층 미시공 등에 기인하는 것을 확인하였습니다. 이 연구의 핵심 성과는 교육시설 누수 하자 예방을 위한 기초적인 자료를 마련하고, FTA 기법을 통해 누수 원인을 분석하여 사전 예방 대책을 도출하는 데 있습니다. 이러한 결과를 토대로 더욱 효과적인 교육시설 관리와 누수 예방에 기여할 것으로 기대된다. In recent years, the construction industry has diligently focused on improving the quality and safety of buildings through smart technologies. However, there is a growing trend of leakage defects, especially in educational facilities, due to aging. The objective of this study is to analyze the causes of these defects in educational environments using the Fault Tree Analysis (FTA) technique and propose preventive measures based on the findings. The FTA technique is explained through a review of domestic literature, and data from the Educational Support Center from 2019 to 2021 are examined to identify major defects. The construction of the Fault Tree (FT) for leakage defects resulted in the identification of 12 basic events. Subsequently, a comprehensive understanding of the causes of leakage is achieved through FTA analysis, leading to the identification of the primary causes of defects. Leakage defects accounted for 46.8% of all reported issues in educational facilities, with roof (ceiling) leaks being the most common problem. FTA analysis revealed that poor substrate treatment was the main cause of roof (ceiling) leaks, which could be attributed to cracks in the waterproof layer, joint cracks, and microvoids in the waterproof layer. The primary achievement of this research is to provide essential data for preventing leakage defects in educational facilities and developing preventive measures through the FTA technique. These results are expected to significantly enhance the management of educational facilities and the prevention of leakage issues.

Effects of energy level, reconstruction kernel, and tube rotation time on Hounsfield units of hydroxyapatite in virtual monochromatic images obtained with dual-energy CT

정대교,이삼선,김조은,허경회,이원진,허민석,최순철 대한영상치의학회 2019 Imaging Science in Dentistry Vol.49 No.4

Purpose: This study was performed to investigate the effects of energy level, reconstruction kernel, and tube rotation time on Hounsfield unit (HU) values of hydroxyapatite (HA) in virtual monochromatic images (VMIs) obtained with dual-energy computed tomography (DECT) (Siemens Healthineers, Erlangen, Germany). Materials and Methods: A bone density calibration phantom with 3 HA inserts of different densities (CTWATER®; 0, 100, and 200 mg of HA/cm3) was scanned using a twin-beam DECT scanner at 120 kVp with tube rotation times of 0.5 and 1.0 seconds. The VMIs were reconstructed by changing the energy level (with options of 40 keV, 70 keV, and 140 keV). In order to investigate the impact of the reconstruction kernel, virtual monochromatic images were reconstructed after changing the kernel from body regular 40 (Br40) to head regular 40 (Hr40) in the reconstruction phase. The mean HU value was measured by placing a circular region of interests (ROIs) in the middle of each insert obtained from the VMIs. The HU values were compared with regard to energy level, reconstruction kernel, and tube rotation time. results: Hydroxyapatite density was strongly correlated with HU values (correlation coefficient=0.678, P<0.05). For the HA 100 and 200 inserts, HU decreased significantly at increased energy levels (correlation coefficient=-0.538, P<0.05) but increased by 70 HU when using Hr40 rather than Br40 (correlation coefficient=0.158, P<0.05). The tube rotation time did not significantly affect the HU (P>0.05). Conclusion: The HU values of hydroxyapatite were strongly correlated with hydroxyapatite density and energy level in VMIs obtained with DECT