• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.331-332
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• 2023

With the aging of buildings, the number and importance of regular inspections of buildings are increasing. The current safety inspection goes through a procedure in which a skilled technician visits an old building, visually checks it, takes a photo, and finally organizes and judges it at the office. For this, field personnel and analysis and review personnel are required. Since the inspection procedure includes taking pictures, a huge amount of data has been accumulated from the time digital photos were used to the present. When a model that can check cracks outside a building is developed using these data, manpower and time required can be greatly reduced. Therefore, this study aims to create a model for classifying cracks that occur outside the building through the artificial intelligence method. The created model can be used as a basic model for determining cracks only by external photography in the future, and furthermore, it can be used as basic data for calculating the size and width of cracks.

• Journal of information and communication convergence engineering
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• v.22 no.3
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• pp.256-266
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• 2024

Sasang constitutional medicine (SCM) is one of the best traditional therapeutic approaches used in Korea. SCM prioritizes personalized treatment that considers the unique constitution of an individual and encompasses their physical characteristics, personality traits, and susceptibility to specific diseases. Facial features are essential for diagnosing Sasang constitutional types (SCTs). This study aimed to develop a real-time artificial intelligence-based model for diagnosing SCTs using facial images, building an SCTs prediction model based on a machine learning method. Facial features from all images were extracted to develop this model using feature engineering and machine learning techniques. The fusion of these features was used to train the AI model. We used four machine learning algorithms, namely, random forest (RF), multilayer perceptron (MLP), gradient boosting machine (GBM), and extreme gradient boosting (XGB), to investigate SCTs. The GBM outperformed all the other models. The highest accuracy achieved in the experiment was 81%, indicating the robustness of the proposed model and suitability for real-time applications.

• Journal of Welding and Joining
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• v.26 no.3
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• pp.37-44
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• 2008

Charpy V-Notch test is commonly used to evaluate fracture toughness. However, since the region to be evaluated is limited to bulk material due to the specimen size required, individual evaluation of micro-structures on weldment is very difficult. In this study, ASP(Advanced Small Punch) test was carried out to evaluate material degradation and fracture toughness on the B.M, W.M and each micro-structures of HAZ for X20CrMoV121 and 2.25Cr1Mo steels with artificial aging time. In addition, to evaluate fracture toughness and material degradation of B.M and W.M of X20CrMoV121 steels with aging times, CVN (Charpy V-notch) test was performed. And then the correlation between ASP and CVN test on X20CrMoV121 steels was obtained. Furthermore, through this correlation, material degradation property of each micro-region of the HAZ in weldment, which was impossible to be evaluated by the CVN test, can be estimated and determined.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.352-356
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• 2006

Quantity of protein, amino acid, and sugar leaked from seeds was greater as the viability of seeds was dropped by the time elapsed of seed aging treatment. In the seeds with the artificial aging treatment for 20 days, 35.8 mg of protein was leaked on the 4th day after soaking, which was 6.9 times higher than that of control. Leakage of amino acid was also higher from low quality seeds treated with the aging treatment. In the seeds with the aging treatment for 20 days, $36.5{\mu}g$ fig of sugar was leaked on the 4th day after soaking, which was 2.8 times higher than that of control. The leakage of inorganic compound was higher from the low quality seeds, and leakage of total protein, amino acid, and sugar. According to .the quantity of leakage, water soluble compounds, which can be used for the assessment of seed quality without any destruction, were protein and potassium. Germination rate and percentage of seeds were dropped with the seed aging treatment, and the seed viability could be recovered by priming treatment. This phenomenon was very clear when the low quality seeds were germinated at low temperature.

• Electrical & Electronic Materials
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• v.10 no.3
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• pp.247-254
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• 1997

Internal voids in insulators give rise to partial discharge, which causes a local breakdown and even entire insulation breakdown. Recently, the necessity of establishing the way to diagnose the aging of insulation materials and to predict of insulation breakdown become important. The purpose of our work are to investigate the treeing phenomena with an artificial needle shaped void by the charge of discharge and acoustic emission pulse in each phase angle area at the same time. We analyzed the .PHI.-QA-t pattern and .PHI.-AEA-t pattern using statistic operators such as pulse magnitude, pulse number, skewness, kurtosis. Therefore, the relation between the charge of discharge and acoustic emission pulse will be helpful to predict the breakdown just before the breakdown occur.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1781-1783
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• 1996

Recently, the necessity of establishing the way to diagnose the aging of insulation materials and to predict of insulation breakdown become important. The purpose of our work are to investigate the treeing phenomena with a artificial needle shape void by the charge of partial discharge and acoustic emission pulse in each phase angle area at the same time. We have analyzed the ${\Phi}-Q-n$ pattern and the insulation diagnosis of the samples using statistic operators such as charge magnitude and A.E pulse factor, skweness, kurtosis, G,C. Therefore, the relation between the charge of partial discharge and A.E pulse will be helpful and efficient to predict the breakdown just before the breakdown occure.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1740-1742
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• 1997

The trend of partial discharges(PD) magnitude which occured in a artificial void at cable joint is investigated as the function of a time. The results have shown that more than 500pC could be sustained for the considerable duration so the efficiency of monitoring a PD magnitude for diagnosing cable joints is confirmed. The other defects at cable joints are now under the same test, we can get the experimental data sooner or later.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.81-82
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• 2018

The structure of the RC structure is actively reinforcing the structure of the building which has suffered from aging, artificial and natural damage of the building. Among various reinforcement methods, epoxy adhesive is used to attach FRP in FRP reinforcement method which is reinforcing by attaching FRP to the structural part. At this time, the epoxy adhesive having a low critical temperature has a sudden adhesive failure upon exposure to heat, and thus, the development of an inorganic fireproof adhesive having a high critical temperature has progressed. Therefore, in this study, the compositional change of inorganic fire - resistant adhesive exposed to high temperature heat was analyzed by XRD.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.2
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• pp.170-176
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• 2002

Nonlinear acoustic effect has been considered as an effective tool for the evaluation of material degradation. In this paper, the applicability of nonlinear acoustic effect to the evaluation of degraded 2.25Cr-1Mo steel is investigated. Firstly, artificial aging was performed to simulate the microstructural degradation in 2.25Cr-1Mo steel arising from long time exposure at $540^{\circ}C$. Secondly, ultrasonic nonlinear parameter was quantitatively measured by bi-spectrum and power spectrum. Nonlinear acoustic parameter from bi-spectrum was found to be clearly sensitive to the aging time.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.5
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• pp.625-634
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• 1986

The strain distribution on a welded aluminum alloy transition joint produced by a static tensile load has been measured using a moire method combined with photoelastic coating method. The test specimens were made of aluminum alloy 6061-T6 and 2014-T6 butt welded with ER-4043 filler metal, and were post welded heat treated (solid solution heat treatment 502.deg. C 70min.) and precipitated (artificial aging 171.deg. C 600min.) to cause an abrupt change of mechanical properties between the base metals and weld metal. The photoelastic epoxy rubber was cemented on the specimen grating which had been reproduced on the specimen surface by using an electropolishing. The measurements were compared with strains computed by Finite Element Analysis. The following results were abtained. (1) The maximum strain were distributed along the center line in the transverse directiion of the weld metal. (2) The strain gradient along the fusion line increased approaching the V-groove tip and the maximum value was observed at a quarter of width from the V-groove tip. (3) The moire method combined with photoelastic coating was proved very useful for real time strain measurement in the welded aluminum alloy transition joint.