• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1216-1223
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• 2008

Displacement control of earth retaining wall is recognized as the most important item for insuring the stability of ground in urban deep excavation site near by major structure such as subway etc. The field monitoring system is classified by two types as manual system and automatic system. The application case of latter type of field monitoring is increased because real time measurement is possible in automatic system and that is correspondent with the recent constructional trend. Though the automatic monitoring system is more useful and advanced than manual monitoring system, accuracy of the system is not verified sufficiently. It was examined that the reliance of automatic monitoring system in this paper through the comparison of monitoring result obtained three urban excavation site in which the each type of monitoring system was executed concurrently. Result of the examination is that the two types of monitoring system is generally alike in view of monitoring result, so the engineering reliance of automatic system was confirmed in case site. This task was researched in restricted case site, it is expected more precise analysis from security of more data monitored and progressive study.

• 천문학회보
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• 제44권2호
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• pp.69.1-69.1
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• 2019

A series of numerical MHD simulations are performed to investigate the evolution of coronal magnetic fields consisting of two flux ropes and an overlying field. Depending on the directions of the axial current and the axial field, two co-helicity cases and two counter-helicity cases are addressed. In Case 1, in which both the axial currents and the axial fields are parallel, flux rope merging bears a huge flux rope with a large winding number. This flux rope naturally erupts, but the whole evolutionary process is rather slow. In Case 2, in which the axial currents are parallel while the axial fields are antiparallel, a self-closed structure is formed and it drives eruption. In Case 3, in which the axial currents are antiparallel and the axial fields are parallel, each flux rope erupts independently and the presence of the other flux rope does not affect the eruption of one flux rope. In Case 4, in which both the axial currents and the axial fields are antiparallel, interaction of the flux ropes and the overlying field effects a breakout reconnection creating an apple-like CME configuration. Our study tells what kind of eruption mechanisms are involved for different eruption features observed.

• 대한치과교정학회지
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• 제29권2호
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• pp.157-163
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• 1999

본 연구의 목적은 교정적 치아 이동시 교정력과 Half sine-wane pulsed electromagnetic field (HSPEMF)를 함께 적용한 경우 교정력 만을 적용한 경우보다 치아 이동량이 증가한다는 가설을 확인하고, HSPEMF의 적용 시간을 다양하게 적용하여 치아 이동이 일어나는 적용 시간의 역치와 적용 시간과 치아 이동량과의 관계를 밝히는데 있다. Hartley guinea pig를 실험 대상으로 하여 상악 좌우측 중절치에 12 g의 이개력을 발휘하는 스프링을 장착하여 실험군에 각각 4 시간, 8 시간 및 12 시간 동안 HSPEMF를 적용한 후 치아 이동량을 측정하여 다음과 같은 결론을 얻었다. 1. 10 일간의 실험 기간 동안 하루 4 시간의 HSPEMF를 적용한 경우 실험군과 대조군에서 치아 이동량이 유의성있는 차이를 보이지 않았다. 2. 10일간의 실험 기간 동안 발생한 치아 이동량에 있어서, 하루 8 시간 및 12 시간의 HSPEMF를 적용한 경우 각각 실험 8 일 및 6 일 이후부터 실험군이 대조군보다 더 큰 유의성 있는 증가를 보였다. 3. 10일간의 실험 기간 동안 발생한 치아 이동량에 있어서, HSPEMF를 하루 12시간씩 적용한 경우가8시간씩 적용한 경우보다 실험 후 7 일과 8 일에서 더 큰 유의성 있는 증가를 보였다.

• 한국BIM학회 논문집
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• 제11권4호
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• pp.20-30
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• 2021

In the era of the 4th industrial revolution, smart construction is actively researched, in the domestic construction field, and one of the key elements in this field is Building Information Modeling(BIM). In Korea, smart construction is being implemented through BIM-based digitization and intelligence. The geotechnical engineering field should also prepare for the introduction of BIM. In this study, the concept and application status of GeoBIM were identified, and the direction of future research was presented. This study is a part of the study "Establishment of GeoBIM-based Digital Twin Maintenance System" in the current "Technology Development for Establishment of Jeju Ground Collapse Response System for Safe Road Operation". The subject and scope of the study is continuous excavation at caves located under roads in Jeju Island, and initial research is being conducted on Jaeamcheon-gul and Jeonggusu-gul. This study aims to build a digital twin through individual data construction and integration processes such as cave shape modeling using laser scanners, 3D stratum modeling using borehole information and geophysical exploration data, and modeling of surrounding conditions using drones.

• 실천공학교육논문지
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• 제8권2호
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• pp.129-136
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• 2016

국내 현장실습의 양적 성장과 더불어 글로벌 현장실습에 대한 관심이 높아지고 정부와 대학의 참여도 증가하는 추세이다. 대학생의 글로벌 현장실습은 학생들에게 선진기업의 발달된 기술과 경험뿐만 아니라 글로벌 역량을 필요로 하는 산업 수요에 적합한 외국어 능력과 글로벌 문화를 습득할 수 있는 기회를 제공함으로써 글로벌 마인드 및 전공 실무능력 배양, 궁극적으로 해외 취업까지 연계시킬 수 있는 장점이 있다. 이러한 글로벌 현장실습을 위해서는 학생의 전공과 관련 있는 기업체 발굴 및 현장실습 커리큘럼 개발, 학생의 안전을 포함한 복합적인 지원이 필요하나 대학의 자원은 매우 제한적인 부분만 가능한 것이 현실이다. 본 논문에서는 외국의 파트너대학과 연계한 현장실습 프로세스 개발 진행으로 글로벌 현장실습을 활성화 시킬 수 있는 방법을 금오공과대학교 사례를 중심으로 제안하였다.

• Earthquakes and Structures
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• 제18권5호
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• pp.625-635
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• 2020

Suspension bridges have the extended in plan configuration which makes them prone to dynamic events like earthquake. The longer span lead to more flexibility and slender of them. So, control systems seem to be essential in order to protect them against ground motion excitation. Tuned mass damper or in brief TMD is a passive control system that its efficiency is practically proven. Moreover, its parameters i.e. mass ratio, tuning frequency and damping ratio can be optimized in a manner providing the best performance. Meta-heuristic optimization algorithm is a powerful tool to gain this aim. In this study, TMD parameters are optimized in different-length suspension bridges in three distinct cases including 3, 4 and 5 TMDs by observer-teacher-learner based algorithm under a complete set of ground motions formed from both near-field and far-field instances. The Vincent Thomas, Tacoma Narrows and Golden Gate suspension bridges are selected for case studies as short, mean and long span ones, respectively. The results indicate that All cases of used TMDs result in response reduction and case 4TMD can be more suitable for bridges in near and far-field conditions.

• Journal of Forest and Environmental Science
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• 제35권3호
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• pp.181-188
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• 2019

This study was performed to construct tree species classification map according to three information types (spectral information, texture information, and spectral and texture information) by altitude (30 m, 60 m, 90 m) using the unmanned aerial vehicle images and the object-based classification method, and to evaluate the concordance rate through field survey data. The object-based, optimal weighted values by altitude were 176 for 30 m images, 111 for 60 m images, and 108 for 90 m images in the case of Scale while 0.4/0.6, 0.5/0.5, in the case of the shape/color and compactness/smoothness respectively regardless of the altitude. The overall accuracy according to the type of information by altitude, the information on spectral and texture information was about 88% in the case of 30 m and the spectral information was about 98% and about 86% in the case of 60 m and 90 m respectively showing the highest rates. The concordance rate with the field survey data per tree species was the highest with about 92% in the case of Pinus densiflora at 30 m, about 100% in the case of Prunus sargentii Rehder tree at 60 m, and about 89% in the case of Robinia pseudoacacia L. at 90 m.

• 대한지구과학교육학회지
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• 제4권2호
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• pp.142-150
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• 2011

This study is aimed to offer the elementary school teacher's experience and awareness about science field trip and science museum field trip, by analyzing the survey of 867 students and 81 teachers in Seoul. Research shows 67.9% high figure of elementary school teacher's experience on science field trip. That experience is include 61.8% of science museum using experience. In case of elementary school teacher's pre-activity is only 53.1% and most of them was visiting Website. Post-activity is more than preceding activity(74.1%) but method is too simple like checking work sheets. 62.3% of elementary school students have been to science field trip and science museum that is higher than teachers'. 66.5% of students said science field trip is influence on science study in good ways but there are some difficulties like lack of pre-activity(33.0%) and unkind information about science museum(21.9%). For activation of science field trip, resources development for effective science field trip operating, program development for pre- and post-activity, school group science field trip program development which is linked science curriculum, complement and expand activity information of science field trip institution.

• International journal of advanced smart convergence
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• 제10권3호
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• pp.245-256
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• 2021

This study is significant in determining the reduction of safety accidents by applying PDCA's theory by subdividing it into a case analysis technique for construction sites by PDCA's theory. For this study, accidents accounted for the largest proportion of each type of disaster in the construction site were considered, and safety accidents were reduced through the PDCA theory through prior research. The analysis method of this study derived improvement plans by applying PDCA techniques to plan, implement, confirm, review, and improve disaster accidents at construction sites. The conclusions of this study are as follows. In the plan, first of all, measures shall be taken to prepare a safety management plan, to verify the implementation of the plan, and to verify the degree of implementation by the field manager. In the implementation, first of all, it is necessary to introduce a safety education history system to strengthen the safety education curriculum to suit the site, as long-term work is impossible for field workers depending on field conditions. First of all, it is necessary to strengthen the installation of safety facilities, including "work scaffolding" and "conducting prevention facilities" at construction sites. In management review and improvement, the risk assessment system for construction sites needs to be expanded first°.

• 통합자연과학논문집
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• 제11권1호
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• pp.30-38
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• 2018

CALPUFF is one of the recommended air pollution models by EPA with AERMOD. It has been used to simulate the ambient concentration of critical air pollutants as well as non-critical pollutants such as persistent organic matters and the organic materials causing odor. In this model, the air pollutants go through dispersion, transportation, chemical reaction, and deposition process. These mechanisms are significantly influenced by meteorological condition. This study produces the meteorological field in three different methods for the simulation of $SO_2$ using CALPUFF: 1) CALMET model by using both ground-level and aerological observation, 2) CALMET model by using MM5 results with NCEP/NCAR reanalyzed data, 3) CALMET model by using MM5 results in which FDDA is applied with NCEP/NCAR reanalyzed data as well as the meteorological data of Korea Meteorological Administration. As a result of CALPUFF model, the resolved concentration of $SO_2$ showed different behaviors in three cases. For the first case, the fluctuation of SO2 concentration was frequently observed while the fluctuation is reduced in the second and third cases. In addition, the maximum concentration of $SO_2$ in the first case was about 2~3 times higher than the second case, and about 4~6 times higher than the third case. These results can be caused by the accuracy of the resolved meteorological field. It is inferred that the meteorological field of the first case could be less accurate than other two cases. These results show that the use of correct meteorological data can improve the result of dispersion model. Moreover, the contribution of various sources such as point, line, and area sources on the ambient concentration of air pollutant can be roughly estimated from the sensitivity analysis.