• 한국콘텐츠학회논문지
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• 제19권5호
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• pp.64-73
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• 2019

본 연구는 전문건설업체의 경쟁력을 평가하기 위해 DEA모형을 활용하여 효율성을 분석하였다. 분석대상기업은 전문건설업 상장업체와 외감업체로 2010년부터 2017년까지 연속자료가 존재하는 300개 기업을 대상으로 하였다. 특히, 전문건설업 유형별 효율성을 비교, 분석하여 그 시사점을 찾는데 중점을 두었다. 의미 있는 분석결과는 다음과 같다. 첫째, 전문건설업체의 효율성은 전반적으로 종합건설업 등과 비교하면 효율성 값이 낮게 분석되었다. 둘째, 전문건설업 유형별 효율성은 시설물축조 및 해체 전문공사업이 가장 높게 나타났다. 이는 해당 업종인 철근 콘크리트공사업, 비계 구조물해체공사업 등이 전문건설업 내에서 상대적으로 효율적임을 의미한다. 셋째, 전문건설업 효율성은 건설경기에 영향을 받는다. 건설경기가 확장국면에 있을 때는 효율성 값이 높고, 수축국면에서는 낮은 효율성 값을 나타내었다. 마지막으로 규모수익성 분석에서 전문건설업은 DRS로 분석되는 경우가 가장 많았다. 이는 규모 확대보다 규모 축소를 통해 기업의 효율성을 높이는 것이 바람직하다는 것을 의미한다.

• 한국물환경학회지
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• 제26권6호
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• pp.986-993
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• 2010

Spatially distributed on-site devices such as bioretentions and bioboxfilters are becoming more common as a means of controlling urban stormwater quality. One approach to modeling the cumulative catchment-scale effects of such devices is to resolve the catchment down to the scale of a land parcel or finer, and then to model each device separately. The focus of this study is to propose a semi-distributed model for simulating urban stormwater quantity and identifying best sites for spatially distributed on-site stormwater control devices in an urban drainage system. A detailed model for urban stormwater improvement conceptualization simulation is set up for a $0.9342km^2$.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.71-72
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• 2014

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.682-683
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• 2013

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.141-142
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• 2012

• 한국농림기상학회:학술대회논문집
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• 한국농림기상학회 2001년도 춘계 학술발표논문집
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• pp.38-38
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• 2001

The rainfall estimates give sufficiently accurate information to map areas which have received the minimum rainfall necessary for outbreaks of pests such as locusts, thus cutting down the cost of searching for likely outbreak sites. At the other end of the scale, satellite rainfall estimates can be used to give timely warnings of changes in river levels and the likelihood of floods in large river catchments.(omitted)

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1140-1142
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• 2000

This paper describes a down-scaled model for a high-speed railway train. The propulsion system of simulator consists of four line-side converters four induction motors driven by two inverters, an eddy current braking system, two dynamic braking systems. The control algorithm of traction and braking including anti-skid control can be developed using the simulator. Simulator design procedure. control algorithm and some experimental waveforms are presented in this paper.

• 한국지진공학회논문집
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• 제5권4호
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• pp.51-66
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• 2001

1936년 7월 4일 경상남도 하동군 화개면을 진앙지로 하는 규모 5의 지진이 발생하였다. 이 지진으로 인하여 쌍계사 경내 건물과 문화재가 손상을 입었으며 금당 앞에 위치한 오층석탑의 탑두(종형석)가 추락하였다. 쌍계사 지진의 세기를 정량적으로 평가하기 위하여 철저한 고층을 거쳐서 실물크기의 석탑 모델을 제작하였다. 제작된 석탑모델을 진동대에 탑재하여 낮은 진폭에서 석탑모델의 동특성을 확인하는 예비시험과 지진파의 지진가속도를 증가시켜 가면서 석탑모델의 거동 특성을 규명하는 본 시험을 실시하였다. 석탑모델의 제작과정과 시험 절차에 관하여 상세히 기술하였고 진동대 시험 결과를 제시하고 그 결과에 관하여 논하였다.

• Wind and Structures
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• 제34권2호
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• pp.199-213
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• 2022

The current study investigates the dynamic effects in the tornado-structure response of an aeroelastic self-supported lattice transmission tower model tested under laboratory simulated tornado-like vortices. The aeroelastic model is designed for a geometric scale of 1:65 and tested under scaled down tornadoes in the Wind Engineering, Energy and Environment (WindEEE) Research Institute. The simulated tornadoes have a similar length scale of 1:65 compared to the full-scale. An extensive experimental parametric study is conducted by offsetting the stationary tornado center with respect to the aeroelastic model. Such aeroelastic testing of a transmission tower under laboratory tornadoes is not reported in the literature. A multiaxial load cell is mounted underneath the base plate to measure the base shear forces and overturning moments applied to the model in three perpendicular directions. A three-axis accelerometer is mounted at the level of the second cross-arm to measure response accelerations to evaluate the natural frequencies through a free-vibration test. Radial, tangential, and axial velocity components of the tornado wind field are measured using cobra probes. Sensitivity analyses are conducted to assess the variation of the structural dynamic response associated with the location of the tornado relative to the lattice transmission tower. Three different layouts representing the change in the orientation of the tower model relative to the components of the tornado-induced loads are considered. The structural responses of the aeroelastic model in terms of base shear forces, overturning moments, and lateral accelerations are measured. The results are utilized to understand the dynamic response of self-supported transmission towers to the tornado-induced loads.

• 한국정밀공학회지
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• 제22권8호
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• pp.42-49
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• 2005

Our purpose is to develop a precision magnetic displacement sensor that has sub-micron resolution and small size probe. To achieve this, we first have tried to establish mathematical models of a magnetic sensor in this paper. The inductance model that presents basic measuring principle of a magnetic sensor is based on equivalent magnetic circuit method. Especially we have concentrated on modeling of magnetic flux leakage and magnetic flux fringing. The induced model is verified by experimental results. The model, including the magnetic flux leakage and flux fringing effects, is in good agreement with the experimental data. Subsequently, based on the augmented model, we will design magnetic sensor probe in order to obtain high performances and to scale down the probe.