• Journal of Korean Association for Spatial Structures
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• v.23 no.3
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• pp.95-103
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• 2023

With the increasing number of aging buildings across Korea, emerging maintenance technologies have surged. One such technology is the non-contact detection of concrete cracks via thermal images. This study aims to develop a technique that can accurately predict the depth of a crack by analyzing the temperature difference between the crack part and the normal part in the thermal image of the concrete. The research obtained temperature data through thermal imaging experiments and constructed a big data set including outdoor variables such as air temperature, illumination, and humidity that can influence temperature differences. Based on the collected data, the team designed an algorithm for learning and predicting the crack depth using machine learning. Initially, standardized crack specimens were used in experiments, and the big data was updated by specimens similar to actual cracks. Finally, a crack depth prediction technology was implemented using five regression analysis algorithms for approximately 24,000 data points. To confirm the practicality of the development technique, crack simulators with various shapes were added to the study.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.8
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• pp.1010-1021
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• 1999

Camouflage measures in military purpose utilize the apparent temperature difference between target and background, so it is essential to develop a thermal analysis program for apparent temperature predictions and to apply some camouflage measures to real military targets for camouflage purpose. In this study, a thermal analysis program including conduction, convection and radiation is developed and the validity of radiation heat transfer terms is examined. The results show that longwave radiation along with solar radiation should be included in order to predict the apparent temperature as well as the physical temperature precisely. Longwave emissivity variation as an effective camouflage measures is applied to a real M2 tank. From the simulation results, it is found that an effective surface treatment, such as painting of a less emissive material or camouflage clothing, may provide a temperature similarity or a spatial similarity, resulting in an effective camouflage.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.666-671
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• 2012

It was diagnosed customer transformers and other equipment by using non-contact infrared equipment. Examiners can identify not only abnormalities in real time in the field of the transformer immediately, as well as they were able to safely perform the scan. Thanks to successful transformer diagnosis, we can easily diagnose abnormalities of transformer itself which can be caused by deterioration of the oil used as overlaod or refrigerant and we can also diagnose abnomalities from low voltage bushing which can be result by external environmental factors and physical factors and abnomalities from its connections at the same time we found it is very useful at proactive diagnostics.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.6
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• pp.469-476
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• 2008

Condition based maintenance(CBM) for the preventive diagnosis of important equipments related to safety or accident in power plant is essential by using the suitable methods based on actual power plant conditions. To improve the reliability and accuracy of the measured value at the minute leak situation, and also to monitor continuously internal leak condition of power plant valve, the development of a diagnosis and monitoring technique using multi-measuring method should be performed urgently. This study was conducted to estimate the feasibility of multi-measuring method using three different methods such as acoustic emission(AE) method, thermal image measurement and temperature difference$({\Delta}T)$ measurement that are applicable to internal leak diagnosis for the power plant valve. From the experimental results, it was suggested that the multi-measuring method could be an effective way to precisely diagnose and evaluate internal leak situation of valve.

• Journal of the Korean Society of Visualization
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• v.8 no.3
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• pp.49-55
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• 2010

Thermal flows inside a laser printer are affected by generated heat from a fuser and boards. Thus, the effect of fans has been investigated to control the thermal flows and behaviors of toners. In order to analyze the phenomena experimentally, a PIV (Particle Image Velocimetry) has been used, and then the flow inside the printer has been predicted by the CFD (Computational Fluid Dynamics) in this study to determine the efficient flow distribution by an optimum design of the printer. The determined optimum design has been confirmed by the developed PIV technique so that the efficiency of the laser printer can be improved by the proposed design.

• Journal of the Korean Graphic Arts Communication Society
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• v.22 no.1
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• pp.1-8
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• 2004

The key points of the CTP board is as follows: Film, brightness, plate exposure is eliminated, the reduction of personal expenses, and the reduction of time consumption. But above all, the accurate reappearance of the highlighting and shadow portion as well as self modification of the dust edge portion stands out as the most impressive improvements. In this paper, using a digital test from 4.0 and a Thermal CTP color printing control, the two parts of the Thermal CTP utilized a 1%-99% dot reappearance. Also, using an opposite line target, the results of the CTP plates and printing were compared. Finally, research was made on the printing quality on the slur development of the plate and the result when there was a lack of weave connection.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.4
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• pp.8-15
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• 1999

The effects of Condebelt press drying on the densification of recycled sheets made from KOCC , AOCC UKP and BKP were examined using CLSM (Confocal Laser Scanning Microscope) and thermal image analysis techniques. It was shown that significant improvement in sheet density, compression strength, tensile strength, surface smoothness was obtained by Condebelt drying. Densification effect by press drying was most prominent for recycled KOCC sheets. And this beneficial effect of Condebelt drying of increasing sheet density and strength was shown to provide opportunities of reducing the utilization ratio of AOCC for cost saving.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.5
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• pp.398-403
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• 2011

Recently, Near-infrared (NIR)colorant is intriguing and attractive but full of challenges. Although some cyanine colorant have been commercialized, near-infrared colorant with intensive NIR absorption, good chemical and photo-stability, and high solubility still remain as target compound. Certain polycyclic aromatic compounds such as quaterrylene represent a key class of NIR colorant and also give rise to outstanding physical and chemical properties after appropriate chemical modification. In this study, We have tried to introduceimide functional group to quaterrylene in order to give chemical and thermal stability. Finally, N,N'-bis (2,6-diisopropylphenyl)-quarterrylene-3,4:13,14-tetracarboximide was synthesized and evaluated its properties using $^1H$ NMR, Maldi-tof, TGA, and UV/VIS/NIR spectroscopy as NIR colorant. The quaterrylene bisimide compound exhibit a excellent thermal stability and chemical stability.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.8
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• pp.624-628
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• 2013

With the recent development of less-costly uncooled detector technology, expensive optics are among the remaining significant cost drivers in the thermography camera. As a potential solution to this problem, the fabrication of IR lenses using chalcogenide glass has been studied in recent years. We report on the molding and evaluation of a ultra-precision chalcogenide-glass lens for the thermography camera for body-temperature monitoring. In addition, we fabricated prototype thermography camera using the chalcogenide-glass lens and obtained the thermal image from the camera. In this work, it was found out that thermography camera discerned body-temperature between 20 and $50^{\circ}C$ through the analysis of thermal image. It is confirmed that thermography camera using the chalcogenide-glass lens is applicable to the body-temperature monitoring system.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.241-244
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• 2006

It is essential to develop a large capacity, non-contact nondestructive inspection system having high reliability to investigate repaired and strengthened structures. Nowadays, an infrared camera is widely used in non-contact nondestructive inspection system. Because an infrared camera is sensitive to the surrounding environment, it is necessary to improve a sensitivity of thermal image information and a relationship between defects and thermal image information. In this papaer, presented is an optimum void detection chart for the optimum conditions to detect infrared rays from inside and outside defects like voids and cracks in concrete structures using extensive computer simulation. Sensitivity studies are performed with respect to variables influencing the temperature distribution such as heating temperature, heating time, and geometries of defect, etc. It may be stated that it could be successfully utilized for the non-contact nondestructive inspection system to detect defects in concrete structures.