• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.4
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• pp.52-67
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• 2020

Recently, the Arctic has been exposed to snow-covered land due to melting permafrost every year, and the Korea Geographic Information Institute(NGII) provides polar spatial information service by establishing spatial information of the polar region. However, there is a lack of spatial information on vegetation sensitive to climate change. This research used a multi-temporal Sentinel-2 image to perform land cover classification of the Ny-Ålesund in Arctic Svalbard. In the pre-processing step, 10 bands and 6 vegetation spectral index were generated from multi-temporal Sentinel-2 images. In image-classification step is consisted of extracting the vegetation area through 8-class land cover classification and performing the vegetation species classification. The image classification algorithm used Random Forest to evaluate the accuracy and calculate feature importance through Out-Of-Bag(OOB). To identify the advantages of multi- temporary Sentinel-2 for vegetation classification, the overall accuracy was compared according to the number of images stacked and vegetation spectral index. Overall accuracy was 77% when using single-time Sentinel-2 images, but improved to 81% when using multi-time Sentinel-2 images. In addition, the overall accuracy improved to about 83% in learning when the vegetation index was used additionally. The most important spectral variables to distinguish between vegetation classes are located in the Red, Green, and short wave infrared-1(SWIR1). This research can be used as a basic study that optimizes input characteristics in performing the classification of vegetation in the polar regions.

• Journal of the Korea Convergence Society
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• v.12 no.6
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• pp.27-32
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• 2021

The purpose of this study was to compare the immediate effect of EMS (electrical muscle stimulation) on rectus femoris thickness during resisted knee extension exercise in healthy adults. This experiment was conducted on 20 healthy adults as pretest-posttest nonequivalent one group design. The subject's 1RM of both knee extension was measured indirectly using an elastic band, and the knee extension resistance exercise using an elastic band was applied to high intensity (80% of 1RM) on the right leg and low intensity (50% of 1RM with EMS) on the left leg, which were applied with 5 sets. Muscle measurements were performed on the rectus femoris (1/2 site, 1/4 site) using ultrasonography before and after exercise. There was a statistically significant difference on the thickness of the rectus femoris in low intensity exercise of the elastic band applied with EMS between pre-test and post-test (p<.05). The results of this study showed that elastic band low intensity exercise combined with EMS had an immediate effective in increasing the thickness of rectus femoris. Based on this result, it is also necessary to verify the effectiveness of intervention methods incorporating low-intensity resistance exercises applying EMS to elderly who cannot exercise high-intensity resistance training in the future, and to develop exercise programs for various body parts.

• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.35-44
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• 2021

The PR (Photo Resist) process in the semiconductor process is a process that uses a mixture of flammable substances. Due to the process equipment is installed in a clean room and when flammable substances leak, there is a high risk of suffocation, fire, and explosion. It is necessary to analyze the impact of accidents that may occur during operation and to evaluate whether the safety of workers can be guaranteed. In this study, the value of radiant heat and temperature change at the monitor point set up virtual inside the clean room was confirmed through CFD simulation of 10 leak and fire scenarios using the FLACS CFD - Fire Module. A fire that occurs inside a clean room transfers high radiant heat to the inter-story structure, but its scope is quite limited, and it is unlikely that it will collapse in a single fire accident. There was no scenario in which two stairs leading to the exit were exposed to high radiant heat at the same time due to a fire accident, therefore workers were able to escape in case of a fire. In addition, it was confirmed that the level of radiant heat and temperature rise rapidly decreased as they moved downstairs. According to the API 520 standard, workers exposed to 6.31 kW/m² of radiant heat that workers can withstand for 30 seconds were confirmed that it was possible to sufficiently escape from the inside.

• Korean Journal of Food Science and Technology
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• v.54 no.2
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• pp.134-140
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• 2022

Kelp belongs to the brown algae family and has been reported to exert anti-cancer effects on some cancer types, however studies have not been reported on the anti-cancer effects of kelp extracts on melanoma. In this study, the anti-cancer effects of kelp extract in B16-F0 cells were investigated, and the underlying molecular mechanisms were assessed. Kelp extract was found to inhibit the proliferation of B16-F0 cells, induce cytotoxicity, inhibit cell colony formation, and induce DNA fragmentation and apoptosis. The molecular mechanism was found to involve kelp extract increasing the expression of cytochrome-c and activated caspase-9 in the intrinsic apoptotic pathway. In addition, kelp extract upregulated the expression of Fas-associated protein with death domain and activated caspase-8 in the extrinsic apoptosis pathway. Activation of caspase-9 and caspase-8 by kelp extract induced activation of caspase-3 and cleaved poly adenosine diphosphate-ribose polymerase, consequently inducing apoptosis. These data suggest that kelp extract represents a potential therapeutic agent for melanoma.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.36 no.1
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• pp.78-95
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• 2023

목적 : 마이크로니들 패치는 피부장벽의 주요 구성성분인 각질층을 관통할 수 있어 일반적인 경피를 통한 약물 전달 수단보다 더 효율적으로 약물을 전달할 수 있다는 장점이 있어 다양한 분야에서 응용되고 있다. 본 임상연구는 아토피피부염 환자의 피부 건조 증상에 대하여 용해성 히알루론산 마이크로니들 패치와 외용제를 병행하여 용해성 마이크로니들 패치의 유효성과 안전성을 평가하였다. 방법 : 본 연구는 단일 기관, 연구자 주도, 평가자 눈가림, 인체 분할 연구로 설계된 무작위 배정 임상시험으로, 피부건조 증상이 있는 아토피피부염 환자 20명을 대상으로 임상연구를 수행하였다. 한 명의 피험자에서 2곳의 시험 병변을 선택한 후, 무작위 배정으로 각각 시험 병변과 대조 병변을 결정하여 2주 동안 매일 양측 병변에 모두 아로마 크림을 도포한 다음, 시험 병변에만 용해성 히알루론산 마이크로니들 패치를 추가로 부착하였다. 결과 : 1차 유효성 평가지표인 local scoring atopic dermatitis(L-SCORAD) index는 치료 후에 시험 병변이 대조 병변보다 유의성 있게 호전되었다. 2차 유효성 평가지표 중 피부 건조감 VAS와 피부 수분 함유량도 시험 병변이 대조 병변보다 유의성 있는 개선을 보였다. Investigator's Global Assessment scale, 소양감 VAS, 경피수분손실량에 있어서는 시험 병변과 대조 병변 모두 치료 후에 유의성 있게 호전되었으나, 두 병변 간의 차이에는 유의성이 없었다. 이상 반응은 나타나지 않았으므로 안전성도 확인되었다. 결론 : 용해성 히알루론산 마이크로니들 패치와 외용제 병행치료는 외용제만 사용하였을 때보다 L-SCORAD index 및 피부 건조감 VAS, 피부 수분 함유량에 있어서 아토피피부염의 증상을 유의성 있게 개선시켰다.

• Clean Technology
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• v.29 no.1
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• pp.71-75
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• 2023

In general, the presence of non-selective intercrystalline (grain boundary) defects in polycrystalline metal-organic framework (MOF) or zeolite membranes, which are known to be ca. 1 nm in size, causes lower membrane performance (selectivity) than the intrinsically expected. In this study we show that applying a thin polymeric coating of polydimethylsiloxane (PDMS) on a polycrystalline MOF membrane is effective to cap the non-selective intercrystalline defects and therefore improve membrane performance. To demonstrate the concept, first, polycrystalline UiO-66, one of Zr-based MOFs, membranes were prepared by an in-situ solvothermal growth. By controlling membrane growth condition with respect to growth temperature, we were able to obtain polycrystalline UiO-66 membranes at 150 ℃ with intercrystalline defects of which the quantity is not significant, so it can be plugged by the suggested PDMS deposition. Second, their performances were compared before and after the PDMS deposition. As expected, the PDMS deposition ended up with a noticeable increase in CO₂/N₂ ideal selectivity from 6 to 14, indicating successful intercrystalline defect plugging. However, the enhancement in CO₂/N₂ selectivity was accompanied by a significant reduction in CO₂ permeance from 5700 to 33 GPU because the PDMS deposition not only plugs defects but also forms a continuous coating on membrane surface, adding an additional transport resistance.

• Clean Technology
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• v.29 no.2
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• pp.109-117
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• 2023

The purpose of this study is to develop a method for separating antioxidants and sugars from grape skin extract. The extract was first mixed with a variety of organic solvents to investigate whether the separation was feasible. When employing acetone, ethanol, dimethylsulfoxide, or dimethylformamide, the organic solvent-extract combination formed a single phase. However, when benzene, ethyl acetate, or n-hexane was added to the extract, the mixture separated into an organic and an aqueous phase and the pigments remained in the aqueous phase. On the other hand, when polyethylene glycol-2,000 (PEG-2000) and sodium citrate were added to the extract, the mixture was separated into three layers, with the majority of the flavonoids migrating to the top layer and 53% of the extract's glucose migrating to the bottom layer. The top layer had significant antioxidant activity, whereas the bottom layer showed no antioxidant activity. The glucose recovery in the bottom layer increased as the molecular weight of PEG increased and the highest recovery (67%) was observed when PEG-8,000 was added. The highest flavonoid separation was observed with PEG-2,000, followed by PEG-8,000 and PEG-400. The flavonoid separation when PEG-2,000 was added resulted in a flavonoid recovery of 48% and 0.2% from the top and bottom layers, respectively. Examining the effect of the separated solution using the agar disc diffusion method on yeast cell growth confirmed that the addition of the extract, the top, and the bottom layer did not inhibit cell growth.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.809-817
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• 2008

This paper deals with the development of ViscoElastic Continuum Damage Finite Element Program (VECD-FEP++) and its verification with the results from both field and laboratory accelerated pavement tests. Damage characteristics of asphalt concrete mixture have been defined by Schapery's work potential theory, and uniaxial constant crosshead rate tests were carried out to be used for damage model implementation. VECD-FEP++ predictions were compared with strain responses (longitudinal and transverse strains) under moving wheel loads running at different constant speeds. To this end, an asphalt pavement section (A5) of Korea Expressway Corporation Test Road (KECTR) instrumented with strain gauges were loaded with a dump truck. Also, a series of accelerated pavement fatigue tests have been conducted at pavement sections surfaced with four asphalt concrete mixtures (Dense-graded, SBS, Terpolymer, CR-TB). Planar strain responses were in good agreement with field measurements at base layers, whereas strains at both surface and intermediate layers were found different from simulation results due to the complexity of tire-road contact pressures. Finally, fatigue characteristics of four asphalt mixtures were reasonably described with VECD-FEP++.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.20-34
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• 2023

Single or multi-layered two-dimensional (2D) materials, with thicknesses in the order of a few nanometers, have garnered substantial attention across diverse research domains owing to their distinct properties, including electrical conductivity, flexibility, and optical transparency. These materials are frequently subjected to repetitive mechanical actions in applications like electronic skin (E-Skin) and smart textiles. Moreover, they are often exposed to external factors like temperature, humidity, and pressure, which can lead to a deterioration in component durability and lifespan. Consequently, significant research efforts are directed towards developing self-healing properties in these components. Notably, recent investigations have revealed promising outcomes in the field of self-healing composite materials, with Ti₃Ci₂Ti_x MXene being a prominent component among the myriad of available 2D materials. In this paper, we aim to introduce various synthesis methods and characteristics of Ti₃Ci₂Ti_x MXene, followed by an exploration of self-healing application technologies based on Ti₃Ci₂Ti_x MXene.

• The Journal of the Acoustical Society of Korea
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• v.42 no.6
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• pp.572-583
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• 2023

Demand for wood in construction is increasing worldwide. In Korea, technical reviews of high-rise Cross Laminated Timber (CLT) buildings are under way. In this paper, Floor Impact Sound Insulation Performance (FISIP) and Transmission Loss (TL) of 150 mm thick CLT floor panels made of two domestic species, Larix kaempferi and Pinus densiflora, are investigated. The CLT slabs were tested in reverberation chambers connected vertically. When comparing Single Number Quantity (SNQ) of FISIP of the bare panels, the Larix CLT is 3 dB lower in heavy-weight and 1 dB in light-weight than the Pinus CLT. However, there was no difference when concrete toppings were added to improve the performance. As the concrete toppings became thicker, the heavy-weight was reduced by 9 dB ~ 20 dB, and the light-weight by 20 dB ~ 30 dB. And the analysis of these results with area density has confirmed that the area densities are highly correlated (R² = 0.94 ~ 0.99) to the FISIP of the CLT. The types of CLT didn't affect the TL. Comparison of theoretical TL values with measured TL values has shown that the frequency characteristics are similar but 8 dB ~ 12 dB lower in measured values. The relationship between the TL and frequency characteristics of the tested CLT slabs was derived by using the correction value.