• 한국건설안전학회 논문집
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• 제3권1호
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• pp.18-24
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• 2020

본 연구의 목적은 지반함몰 사고를 예방하기 위한 제도 개선안을 제안하는 것이다. 이를 위해 다음과 같은 수행절차를 따른다. 첫째, 지반침하 및 지반함몰 등의 혼용되어 사용되는 용어를 정의한다. 둘째, 지반함몰 사고 현황 및 원인 분석과 강우량과 지반함몰 원인간의 상관관계 분석을 실시하여 중점관리 원인을 도출한다. 셋째, 중점관리 원인에 대한 제도 개선안을 제안한다. 그 결과, 지하관로 손상과 지하공사 부실이 중점관리 원인으로 규명되었으며, 이를 관리할 두 가지의 제도 개선안을 제시하였다. 본 연구의 결과는 향후 보다 실효성 있는 지하함몰 예방을 위한 제도개선의 기초자료로 활용될 수 있다.

• 한국안전학회지
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• 제32권6호
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• pp.104-109
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• 2017

As the ground subsidence occurred at the center of Seoul area in 2014, the ground subsidence phenomenon was emerged as a social issue in Korea. Even so far, national and local governments and related experts have been making a lot of efforts to prevent ground subsidence phenomenon, but it is still happening all over the country. In this study, we chose 9 influence factors on which ground subsidence and derived weights using AHP(Analytic Hierarchy Process) method for ground subsidence risk analysis. And we analyze the risk of subsidence in ${\bigcirc}{\bigcirc}$city using GIS(Geographic Information System) analysis method and evaluate the potential risk.

• 한국항공우주학회지
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• 제44권8호
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• pp.718-727
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• 2016

우리나라 지상시스템은 위성 관제와 탑재체자료 처리를 위해서 1990년대부터 개발되기 시작하였다. 과학위성, 저궤도위성 및 정지궤도 지상시스템의 초기 개발 시에는 국제기술협력 등이 필요하였으나, 초기 기술 확보 이후에는 국내 독자 기술로 개발되기 시작하였다. 우리나라는 지금까지 총 14기의 지상시스템을 개발하였으며, 본 논문은 이러한 경험을 바탕으로 발전 전망 및 방향을 제시한다. 관제시스템은 재구성, 재사용, 자동화 기술을 기반으로 하는 다중위성 관제시스템 개발이 필요하다. 처리시스템은 다양한 탑재체자료 처리 기술의 확보와 처리정확도 향상을 위한 검보정 기술의 접목이 필요하다. 또한, 탑재체 자료 양의 증가로 인한 고속처리 기술 확보와 처리된 탑재체자료를 사용자 간에 사용하고 통합하는 상호운영성 연구가 필요하다. 끝으로, 다양한 종류의 많은 위성을 운영할 수 있도록 국내외에 분포된 안테나 등 국가 지상시스템 인프라 망 구축이 필요하다.

• 한국터널공학회:학술대회논문집
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• 한국터널공학회 2005년도 학술발표회 논문집
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• pp.270-281
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• 2005

An especial attention for old tunnel safety is required on increasing of The various tunnel recently. Specially, the lining investigation method of the old tunnel will be able to presume condition of concrete lining indirectly. Because it is many restriction thought of environment and ground condition investigation method of tunnel lining rear. This study carried out section & convergence measurement of part which was deformed in tunnel lining. It had been observed for the change of tunnel behavior with a continuous measurement. It has been analyzed for a cause of tunnel deformation and inspected for the effect after a repair-reinforcement to tunnel compared with the effect before those by structure analysis. By establishing automatic measurement system after repair-reinforcement to tunnel, it would be accomplished to convergence measurement continually. As a result, it was observed that deflection and deformation of tunnel was convergent. but it should be followed to a continuous maintenance because of unstable ground condition, cause of inner tunnel, environment. The railroad tunnel which was executed a reinforcement of the tunnel lining must investigate the close condition of reinforcement lining and concrete lining.

• Journal of Astronomy and Space Sciences
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• 제24권4호
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• pp.389-396
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• 2007

The Global Navigation Satellite System (GNSS) becomes more important and is applied to various systems. Recently, the Galileo navigation system is being developed in Europe. Also, other countries like China, Japan and India are developing the global/regional navigation satellite system. As various global/regional navigation satellite systems are used, the navigation ground system gets more important for using the navigation system reasonably and efficiently. According to this trend, the technology of GNSS Ground Station (GGS) is developing in many fields. The one of purposes for this study is to develop the high precision receiver for GNSS sensor station and to provide ground infrastructure for better performance services on navigation system. In this study, we consider the configuration of GNSS Ground Station and analyze function of Monitoring and Control subsystem which is a part of GNSS Ground Station. We propose Monitoring and Control subsystem which contains the navigation software for GNSS Ground System to monitor and control equipments in GNSS Ground Station, to spread the applied field of navigation system, and to provide improved navigation information to user.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.432-439
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• 2009

This research project was carried out to develop the technique to assess quantitatively and rapidly the stability of a tunnel by using the measured displacement at the tunnel construction site under excavation. To achieve this purpose, a critical strain concept was introduced and applied to an assessment of a tunnel under construction. The new technique calculates numerically the strains of the surrounding ground by using the measured displacements during excavation. A numerical practical system was developed based on the proposed analysis technique in this study. The feasibility of the developed analysis module was verified by incorporating the analysis results obtained by commercial programs into the developed analysis module. To verify the feasibility of the developed analysis module, analysis results of models both elastic and elasto-plastic grounds were investigated for the circular tunnel design. Then the measured displacements obtained in the field are utilized practically to assess the safety of tunnels using critical strain concept. It was verified that stress conditions of in-situ ground and ground material properties were accurately assessed by inputting the calculated displacement obtained by commercial program into this module for the elastic ground. However for the elasto-plastic ground, analysis module can reproduce the initial conditions more closely for the soft rock ground than for the weathered soil ground. The stability of tunnels evaluated with two types of strains, that is, the strains obtained by dividing the crown displacement into a tunnel size and the strains obtained by using the analysis module. From this study, it is confirmed that the critical strain concept can be fully adopted within the engineering judgment in practical tunnel problems and the developed module can be used as a reasonable tool for the assessment of the tunnel stability in the field.

• 한국항공우주학회지
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• 제40권9호
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• pp.800-806
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• 2012

본 논문은 지상지원과 지상관제의 기능을 결합한 무인항공기의 비행시험을 위한 통합형 지상지원시스템(Ground support system)에 대한 설계 및 개발에 관해 기술한다. 통합비행시험은 비행체의 성능을 검증하기 위한 필수적인 절차이다. 개발한 통합형 지상지원시스템은 비행시험에 필요한 인적 물적 자원과 시간을 절감하고 비행시험의 체계적인 준비와 진행을 하기 위한 인프라로써 비행시험의 제반 사항을 갖추어 지상관제, 통신, 발전, 장비의 수송, 수리와 유지 등이 가능하며 소규모 연구소에서 2~3명의 인원으로 운용하기에 적합한 수준이다.

• Earthquakes and Structures
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• 제7권6호
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• pp.1283-1301
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• 2014

Ground motion modification is extensively used in seismic design of civil infrastructure, especially where few or no recorded ground motions representative of the design scenario are available. A site in Los Angeles, California is used as a study site and 28 ground motions consistent with the design earthquake scenario are selected. The suite of 28 ground motions is scaled and modified in the time domain (TD) and frequency domain (FD) before being used as input to a bilinear SDOF system. The median structural responses to the suites of scaled, TD-modified, and FD-modified motions, along with ratios of he modified-to-scaled responses, are investigated for SDOF systems with different periods, strength ratios, and post-yield stiffness ratios. Overall, little difference (less than 20%) is observed in the peak structural accelerations, velocities, and displacements; displacement ductility; and absolute accelerations caused by the TD-modified and FD-modified motions when compared to the responses caused by the scaled motions. The energy absorbed by the system when the modified motions are used as input is more than 20% greater than when scaled motions are used as input. The observed trends in the structural response are predominantly the result of changes in the ground motion characteristics caused by modification.

• 한국지반신소재학회논문집
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• 제16권3호
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• pp.1-10
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• 2017

최근 발생하고 있는 자연재해 중 산사태와 관련된 재해는 막대한 인명과 재산피해를 발생시키고 있다. 지속적으로 발생하고 있는 산사태로 인한 피해를 최소화하기 위해서는 계측, 모니터링 시스템 등 관련 기술에 대한 과학적 관리체계가 필요하다. 본 연구는 사면붕괴 예측을 통한 산사태 피해저감을 위한 관리체계 확립을 목적으로 하고 있다. 이를 위해 산사태 발생시 지반거동을 예측하기 위한 표층지반변형률 봉을 제작하고, 사면 붕괴전조로서 변형률 증가를 관측하였다. 그 결과, 사면 붕괴시 지반의 변형은 붕괴 전조 구간, 변형 가속 구간, 변형 급가속 구간을 거친 후 붕괴에 이르는 것으로 나타나, 붕괴 전조 예측과 상관관계가 있는 것으로 판단된다. 모든 조건에서 사면붕괴 전조로서 시간에 따른 변위량의 증가가 공통적으로 관측되었으며, 이는 붕괴위험 사면의 계측 및 유지관리 관점에서 대단히 중요한 현상으로 판단된다. 산사태 발생에 따른 지반변위는 향후 지속적 연구를 통해 사면붕괴예측 및 계측관리기준의 기초자료로 활용될 수 있을 것으로 사료되며, 산사태 피해저감 및 계측산업 활성화에 기여할 수 있을 것으로 판단된다.

• Journal of Electrical Engineering and Technology
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• 제6권3호
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• pp.364-368
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• 2011

The super-speed tube train was introduced to increase the speed of ground transportation. It levitates magnetically and runs in a partial vacuum tube, which significantly reduces air resistance. However, strong magnetic force sufficient to propel the massive train can affect the infrastructure. The induced eddy current produces joule heat, and raises the inside temperature of the girder, which might lead to electrochemical corrosion on the girder, thereby weakening its durability. In this paper, the authors analyzed the magnetic flux and induced eddy current in the reinforced concrete girder by using three-dimensional FEM, particularly by varying the number of reinforcing steels of the upper flange of the girder to the condition of almost the same flexural strength and reinforcing steel amount.