• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.97-102
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• 2011

The size of TV and TFT-LCD are bigger and bigger for the next generation exposure equipment install that existing fab are getting a lot of additions. When the new fab build an extension that the shortening of the construction and non-vibration are use cast in place concrete pile method. In this study when lay the foundation of existing fab adjoin use vibration monitoring system are rotator type all casing method among cast in place concrete pile method. The evaluation of ground vibration of rotator type all casing method effect to precision equipment and vibration area of influence.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.11-16
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• 2009

Better understanding of in-situ mechanical behavior of pavement foundations is very important to predict long-term effects on the system performance of transport infrastructure. In order to do that, resilient stiffness characterization of geomaterals is needed to properly adopt such mechanistic analysis under both traffic and environmental loadings. In this paper, in situ monitoring data from KHC test road was used to analyze the non-linearity of stress conditions under traffic and moisture loadings. Then, the predicted non-linear response using finite element method with a selected constitutive model of foundation geomaterials are verified with the field data.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.4
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• pp.396-403
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• 2016

Objectives: The study is to evaluate biological monitoring and risk assessment for epichlorohydrin-bisphenol A resin exposed from waterproofing or finishing work in the apartment building construction. Methods: Subjected workers were working on spray-painting and waterproofing work for 8 hours per day every 20 days. The urine samples were collected at the end of 20 days working period. For urinary bisphenol A as metabolite from epichlorohydrin-bisphenol A exposure, urine samples were analyzed with liquid chromatography mass-mass spectrometry(HPLC-MS/MS). Results: Geometric means of urinary bisphenol A(BPA) with no hydrolysis and with enzymic hydrolysis(BPA-EH) in the workers were $1.10{\mu}g/L$ and $2.90{\mu}g/L$. BPA-EH was 4 times higher than that of control group. The factors for working period and ages did not affect the variation of BPA and BPA-EH. The levels for BPA and BPA-EH were not higher than 95th percentile for exposure on human-life environment. Conclusions: The BPA and BPA-EH were therefore effective biological markers for epichlorohydrin-bisphenol A exposure workers, but not seem to hazardous exposure level. Waterproofing work in construction workshop is required to measuring work environment and health care management for the workers.

• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.115-122
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• 2018

This study examined the effect of safety leadership coaching program on managers' safety management and workers' safety behaviors in construction site. Three or four managers and about one hundred workers at each site participated in this study. Safety leadership coaching program consisted of safety leadership education, goal setting, self-monitoring and feedback on workers' safety behavior, reward for three safety management behaviors; (1) safety observations of workers safety behavior and (2) providing positive feedback on safe behavior (3) providing corrective feedback on risk behavior and daily safety education for workers. Dependent variables were the percentage of safe behaviors of workers and frequency of managers' safety management behaviors. A nonconcurrent AB multiple baseline design across settings was adopted. After baseline(A), safety leadership coaching program (B) was introduced to each site. The results showed that safety leadership coaching program was effective to increase managers' and workers' safety behaviors. These results suggest that safety leadership coaching program developed in this study would be an alternative treatment technique to improve construction safety management. In addition, the implications, limitations of this study, and future studies are discussed.

• Journal of Environmental Science International
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• v.24 no.12
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• pp.1691-1703
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• 2015

When constructing tunnels, it is important to understand structural, geological and hydrogeological conditions. Geumgeong tunnel that has been constructed in Mt. Geumjeong for the Gyeongbu express railway induced rapid drawdown of groundwater in the tunnel construction area and surroundings. This study aimed to analyze groundwater flow system and baseflow using long-term monitoring and groundwater flow modeling around Geumgeong tunnel. Field hydraulic tests were carried out in order to estimate hydraulic conductivity, transmissivity, and storativity in the study area. Following the formula of Turc and groundwater flow modeling, the annual evapotranspiration and recharge rate including baseflow were estimated as 48% and 23% compared to annual precipitation, respectively. According to the transient modeling for 12 years after tunnel excavation, baseflow was estimated as $9,796-9,402m^3/day$ with a decreasing tendency.

• Journal of the Korea Concrete Institute
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• v.18 no.2 s.92
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• pp.293-298
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• 2006

The reinforced concrete(RC) structures strengthened with fiber reinforced plastic(FRP) has been accepted by the construction engineering community for rehabilitation. FRP composites can present many advantages like a corrosion resistance, strength-weight ratio, relatively short application time, and cost effectiveness. The beams under design load, however, are cracked and result in degrading the strength. It is difficult to recognize cracks and deflections on the surface of the concrete members retrofitted with FRP through the life cycle. For these reasons, if they result in the effects, which were below the expected strength, we must monitor the state of concrete structures all the time in order to take an appropriate measure. Fiber Bragg Grating(FBG) sensor excel as monitoring of investigating the stress state of the retrofitted beams with FRP. The main objective of this study is to measure strain by experiment and analyze the behavior of RC beams retrofitted with FRP using FBG sensor. The kinds of FRP which were used in research are carbon, glass and improved hybrid FRP(IFRP) that has capacity than any other FRP. Other variables are the length of FRP, the number of sheet.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.246-249
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• 2009

Test and launch facilities which use oxygen as the propellant of a launch vehicle have hazards of fire and explosion by the leakage of oxygen. Also, the personnel operating the facilities, which use the high-pressured gases like nitrogen and helium in the closed room, is exposed to the hazard of death from suffocation. Consequently, we should keep out of the hazards and the accidents by monitoring the contents of oxygen in the air. The method and the system construction for monitoring oxygen contents in the air and the results from its application to Naro space center are described on this paper.

• Smart Structures and Systems
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• v.15 no.6
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• pp.1543-1567
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• 2015

In this study, a wireless crack sensor is developed for monitoring cracks propagating in two dimensions. This sensor is developed by incorporating a laser-based optical navigation sensor board (ADNS-9500) into a smart wireless platform (Imote2). To measure crack propagation, the Imote2 sends a signal to the ADNS-9500 to collect a sequence of images reflected from the concrete surface. These acquired images can be processed in the ADNS-9500 directly (the navigation mode) or sent to Imote2 for processing (the frame capture mode). The computed crack displacement can then be transmitted wirelessly to a base station. The design and the construction of this sensor are reported herein followed by some calibration tests on one prototype sensor. Test results show that the sensor can provide sub-millimeter accuracy under sinusoidal and step movement. Also, the two modes of operation offer complementary performance as the navigation mode is more accurate in tracking large amplitude and fast crack movement while the frame capture mode is more accurate for small and slow crack movement. These results illustrate the feasibility of developing such a crack sensor as well as point out directions of further research before its actual implementation.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.175-175
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• 2023

Detection and monitoring of wildfires are essential for limiting their harmful effects on ecosystems, human lives, and property. In this research, we propose a novel method running in the Google Earth Engine platform for identifying and characterizing burnt regions using a hybrid of Sentinel-1 (C-band synthetic aperture radar) and Sentinel-2 (multispectral photography) images. The 2022 Uljin wildfire, the severest event in South Korean history, is the primary area of our investigation. Given its documented success in remote sensing and land cover categorization applications, we select the Random Forest (RF) method as our primary classifier. Next, we evaluate the performance of our model using multiple accuracy measures, including overall accuracy (OA), Kappa coefficient, and area under the curve (AUC). The proposed method shows the accuracy and resilience of wildfire identification compared to traditional methods that depend on survey data. These results have significant implications for the development of efficient and dependable wildfire monitoring systems and add to our knowledge of how machine learning and remote sensing-based approaches may be combined to improve environmental monitoring and management applications.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.9
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• pp.86-93
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• 2011

The necessity of Power Quality(PQ) Management grow bigger because the disturbance strength in power system is increasing, on the other hand, the tolerance of electrical components is reducing with widely use of the IT and digital equipments. The domestic management standards on power quality are enacted based on the IEC standards in recent. Since the IEC standards defines the measurement and evaluation point on PQ as PCC(Point of Common Coupling) which is normally the point of penetration between customer and power company, the PQ monitoring system(PQMS) should be made to measure and manage the PQ of custom effectively. In this paper, therefore, the economical construction plan on PQMS using the wireless communication channel in distribution automation system is suggested, and the usefulness of the PQMS are shown by analyzing the PQM data with IEC standards.