• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.3
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• pp.225-239
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• 2004

In this paper, systematic analyses for the shoring systems installed to support applied loads during construction are performed on the basis of the numerical approach introduced in the previous study. Structural behaviors require changes in design variables such as types of shoring systems, shore stiffness and shore spacing. In this paper, the design variable are analyzed and discussed. The time dependent deformations of concrete and construction sequences of frame structures are also taken into account to minimize structural instability and to improve design of shoring system, because those effects may increase axial forces delivered to shores. From many parametric studies, it can be recommended that the most effective shoring system is 2SlR(two shores and one reshore)

• Journal of Korean Society of Disaster and Security
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• v.12 no.3
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• pp.59-67
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• 2019

In this study, the UAV (Unmammed Aerial Vehicle) was applied for the photogrammetry of the construction site and the safety management of steel pipe scaffold. The research site is a temporary facility for building reinforcement on Samcheok Campus of Kangwon National University. The installation condition of the steel pipe scaffold was investigated, and the pillar distance, the beam distance and the wale distance were surveyed. As a result, it was found that the beam distance of the scaffold in the longitudinal direction was in good agreement with the standard, but the pillar distance and the wale distance were found to be less than the standard. Three-dimensional data can be used in drone shooting to enable three-dimensional measurement, so that it is possible to measure facilities hidden or located inside other facilities. Through the drone shooting, the condition of the site can be quickly recorded and the surveying can be carried out without interfering with the work of the field personnel. Although the installation of the temporary structure must be strictly observed to ensure the safety of the workers, it is found that the installation standards are still neglected in the field. In order to prevent this practice, it was thought that the legal system should be supplemented so that it could be checked periodically by using UAV in the field process management.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.301-311
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• 2012

The law(construction standard specification, construction, standard-work regulation, Industry safety standard related regulation) related to the installation of scaffolding being used commonly on the construction site is regulated that the gap of ledger is within 1.5m and first ledger is within 2m. The gap of ledger here is essential for the stability of scaffolding structure. But it is determined that it is possible for the gap of ledger is applied by explaining safety handrail as ledger, because of the fact that in current, on the construction site, safety handrail is installed with the material of scaffolding ledger as a steel tube pipe. On this study, it is aimed to guarantee the safety by analyzing the ledger of scaffolding practically and prevent the accident of manager and laborer through the actualization.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.781-787
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• 2010

Forecasting possible failure characteristics is very important in maintenance planning because it helps in predicting any future failures and determining the optimum replacement interval. This paper examines the time.to-failure distribution of the transfer gearbox of a J79 engine by using a probability plotting technique which is one of the most convenient techniques for reliability analysis. Various probability distributions are evaluated for determining the suitable probability distribution of the failure data of the transfer gearbox, and the resulting correlation coefficient indicates that failure data have a lognormal distribution. The expected number of unscheduled maintenance actions and the optimum replacement interval for various values of cost ratios are determined.

• The Korean Journal of Pesticide Science
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• v.17 no.3
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• pp.168-177
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• 2013

This experiment was carried out to estimate leaching potential of thirteen endocrine disruptor-suspected pesticides in upland soils using soil columns (5 cm I.D. ${\times}$ 35 cm H.) packed with soil A (sandy loam) and soil B (loam). When 12.6 mL of water, average precipitation in Cheongju area during the period from June to August, 2001-2010, was percolated through soil column packed with soil A every day for 21 days, no pesticides were detected from leachate, with the exception of metribuzin which was detected with negligible. Also, when 2 L of water was percolated consecutively five times through soil columns packed with soil A and B, irrespective of soil types, cypermethrin, endosulfan, fenvalerate, parathion and trifluralin, which were very low water solubilities and high soil $K_{oc}s$, were not detected from leachate and were distributed mostly in the depth of 0-5 cm, representing that water solubility and soil $K_{oc}$ are major contributing factors to their leaching behavior. Despite high average leaching rates in carbaryl and methomyl, actual possibilities of ground water contamination in the agricultural environment by them would be very low, considering that the negligible amount of pesticide was percolated through a lysimeter with an undisturbed soil core simulating the field conditions, while most of pesticide was percolated through a soil column with the disturbed soil profile.

• Journal of Wetlands Research
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• v.16 no.2
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• pp.205-212
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• 2014

Ultrasound technology can be applied in various fields including environmental, energy, and material engineering processes. In this study the effect of liquid height/volume on calorimetric energy and sonochemical oxidation was investigated as one of the basic steps for the design of water/wastereater treatment sonoreactors. The liquid height was increased from 0 to $4{\lambda}$ by $1/4{\lambda}$ and it was found that both calorimetric energy and sonochemical oxidation were significantly increased at relatively high liquid height/volume where the power density was relatively low. The sonochemiluminescence (SCL) images for the visualization of the activity of cavitation also showed that larger and more stable active zone was formed with high SCL intensity at high liquid height/volume. Therefore, it was revealed that sonoreactors for water/wasterwater treatment could be significantly effective in terms of removal efficiency and energy consumption.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.9-9
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• 2001

내분비계 장애물질 중 관찰물질로 지정된 bisphenol A(BPA)의 투여가 생쥐의 번식 효율에 미치는 영향을 규명하기 위하여 웅성 ICR 생쥐에 무처리구, corn oil, 0.05, 0.5 및 5.0mg BPA/kg b.w의 BPA을 3일 간격으로 5회 투여했으며, 자성 ICR 생쥐도 웅성생쥐와 동일하게 3일 간격으로 5회 투여한 후, 웅성은 투여후 2일, 자성은 7일후에 모든검사를 실시하였다. BPA의 투여가 웅성 생쥐의 번식기관무게에 미치는 영향을 조사한 결과는 체중, 정소상체, 정낭선 및 응고선의 무게는 투여구간에 커다란 차이가 없었으며(P>0.05), 정소의 무게는 5.0mg 투여구가 여타구보다 다소 낮은 무게를 나타냈다. BPA의 투여가 웅성 생쥐의 정액성상에 미치는 영향을 조사한 결과, 생존율과 유효 정자수는 각 투여구간에 커다란 차이가 없었으나 총정자수는 각각 35.50, 35.73, 36.33, 33.13 및 29.28$\times$$10^{7}$ 정자/$m\ell$로서 5.0mg 투여구가 여타구보다 통계적으로 유의하게 낮은 결과을 나타냈다(P<0.05). 기형율은 5.0mg 투여구가 23.15%로서 무처리구(18.13%), 대조구(18.58%) 및 0.05mg 투여구(19.68%)보다 통계적으로 유의하게 높은 기형율을 나타냈다(P<0.05). 웅성 생쥐에 BPA의 투여가 혈액의 일반성분에 미치는 영향을 조사한 결과, RBC, Hb, HT, MCV, MCH 및 MCHC는 각 투여구간에 차이가 없었으며, WBC는 BPA 투여구가 무처리구 및 대조구보다 다소 낮은 수치를 나타냈으며, PLT는 BPA 투여구가 무처리구 및 대조구보다 높은 수치를 나타냈다. BPA의 투여가 자성 생쥐의 번식기관무게에 미치는 영향을 조사한 결과, 체중은 투여구간에 커다란 차이가 없었으며 자궁의 무게는 BPA 투여구가 대조구에 비해 다소 논은 무게를 나타냈다. 오른쪽 난소의 무게는 0.5mg 투여구와 5.0mg 투여구가 각각 0.0059 및 0.0061g으로 대조구(0.0081g)와 0.05mg 투여구(0.0071g)보다 낮은 무게를 나타냈으며, 왼쪽 난소의 무게는 각각 0.0076, 0.0076, 0.0058 및 0.0061g으로 0.5mg 투여구가 대조구와 0.05mg 투여구보다 낮은 무게를 나타냈다(P<0.05). BPA의 투여가 자성 생쥐의 혈구화학치에 미치는 영향을 조사한 결과, RBC, Hb, HT, MCV, MCH 및 MCHC는 각 투여구간에 차이가 없었으며, WBC는 BPA 투여구가 대조구보다 다소 높은 수치를 나타냈다. PLT는 0.5mg 투여구와 5.0mg 투여구가 대조구보다 다소 높은 수치를 나타냈다. 정소, 난소 및 자궁의 조직, 병리학적인 검사에서는 모든 투여구간에 커다란 차이가 없었다.