• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.725-744
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• 2022

As the construction of infrastructure using the underground tunnel in urban area have been rapidly increased, various accidents and collapses of tunnel including structure have been occurred in deep urban tunnelling. The concern and worry relating to the risk and safety of the tunnel during excavation is becoming the key issues in deep urban tunnelling. In this study, it was conducted for deep urban tunnel at GTX (Great Train Express) line which was located in Seoul metropolitan area to determine the risk characteristics for tunnel according to urban tunnelling. Also, it was reviewed the risk analysis and evaluation of the tunnel, shaft and station. And after a review of risk analysis and evaluation for risk register and hazard identification by using a risk matrix method, safety management of the tunnel according to excavation was evaluated to be secured. This study is expected to be applied as useful approach in deep urban tunnelling if you need to review the risk and safety management system of tunnel according to mitigation measures in complex urban tunnelling.

• Journal of the Korean institute of surface engineering
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• v.54 no.5
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• pp.230-237
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• 2021

In this study, the influence of silicon contents on the microstructure, mechanical and tribological properties of Ti-Al-Si-N coatings were systematically investigated for application of cutting tools. The composition of the Ti-Al-Si-N coatings were controlled by different combinations of TiAl₂ and Ti₄Si composite target powers using an arc ion plating technique in a reactive gas mixture of high purity Ar and N₂ during depositions. Ti-Al-Si-N films were nanocomposite consisting of nanosized (Ti,Al,Si)N crystallites embedded in an amorphous Si₃N₄/SiO₂ matrix. The instrumental analyses revealed that the synthesized Ti-Al-Si-N film with Si content of 5.63 at.% was a nanocomposites consisting of nano-sized crystallites (5-7 nm in dia.) and a three dimensional thin layer of amorphous Si₃N₄ phase. The hardness of the Ti-Al-Si-N coatings also exhibited the maximum hardness value of about 47 GPa at a silicon content of ~5.63 at.% due to the microstructural change to a nanocomposite as well as the solid-solution hardening. The coating has a low friction coefficient of 0.55 at room temperature against an Inconel alloy ball. These excellent mechanical and tribological properties of the Ti-Al-Si-N coatings could help to improve the performance of machining and cutting tool applications.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.1
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• pp.815-824
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• 2019

It is not easy to present a generalized operating model because the operating environment of a sport event is composed of a complex matrix structure. In this study, we propose 'standardization' which provides guidance of concept and process of sport event management to solve this sports event management problem. To purpose complete of this study, the frame was developed by the international standard ISO 9001: 2015 is applied. The standards framework for sports event process management system structure proposed in this study consists of scope of application, citing standard, Terms and definitions, organizational situation, leadership, planning, support, operation, performance evaluation, and improvement. This sport event process management system standard can be applied to any organization that wants to host, prepare, and operate sport events regardless of the form or scale of the sport event. In addition, this standard was focused on process management of life-cycle stages of sporting events, therefor it was possible to manage interrelationships and dependencies between processes and processes.

• Analytical Science and Technology
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• v.34 no.2
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• pp.37-45
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• 2021

A rapid and simple LC-MS/MS analytical method in determining Jaspine B has been developed and validated in rat plasma. The standard curve value was 25 - 5000 ng/mL and the linearity, inter-day and intra-day accuracy and precision were within 15.0 % of relative standard deviation (RSD). The mean recoveries of Jaspine B ranged from 87.5 % to 91.2 % with less than 3.70 % RSD and the matrix effects ranged from 91.1 % to 108.2 % with less than 2.6 % RSD. The validated LC-MS/MS analytical method of Jaspine B was successfully applied to investigate the dose-escalated pharmacokinetic study of Jaspine B in rats following an intravenous injection of Jaspine B at a dose range of 1 - 10 mg/kg. The initial plasma concentrations and area under plasma concentration curves showed a good correlation with intravenous Jaspine B dose, indicating the dose independent pharmacokinetics of Jaspine B in rats. In conclusion, this analytical method for Jaspine B can be easily applied in the bioanalysis and pharmacokinetic studies of Jaspine B, including its administration at multiple therapeutic doses, or for making pharmacokinetic comparisons for the oral formulations of Jaspine B in small experimental animals as well as in vivo pharmacokinetic-pharmacodynamic correlation studies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.1
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• pp.84-89
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• 2019

JPEG is a most widely used standard image compression technology. This research introduces the JPEG image compression algorithm and describes each step in the compression and decompression. Image compression is the application of data compression on digital images. The DCT (discrete cosine transform) is a technique for converting a time domain to a frequency domain. First, the image is divided into 8 by 8 pixel blocks. Second, working from top to bottom left to right, the DCT is applied to each block. Third, each block is compressed through quantization. Fourth, the matrix of compressed blocks that make up the image is stored in a greatly reduced amount of space. Finally if desired, the image is reconstructed through decompression, a process using IDCT (inverse discrete cosine transform). The purpose of this research is to review all the processes of image compression / decompression using the discrete cosine transform method.

• Metals and materials international
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• v.24 no.6
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• pp.1359-1368
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• 2018

The mechanical properties and microstructure evolution of Mg-8Li-3Al-1Y alloy undergoing different rolling processes were systematically investigated. X-ray diffraction, optical microscope, scanning electron microscopy, transmission electron microscopy as well as electron backscattered diffraction were used for tracking the microstructure evolution. Tensile testing was employed to characterize the mechanical properties. After hot rolling, the $MgLi_2Al$ precipitated in ${\beta}-Li$ matrix due to the transformation reaction: ${\beta}-Li{\rightarrow}{\beta}-Li+MgLi_2Al+{\alpha}-Mg$. As for the alloy subjected to annealed hot rolling, ${\beta}-Li$ phase was clearly recrystallized while recrystallization rarely occurred in ${\alpha}-Mg$ phase. With regard to the microstructure undergoing cold rolling, plenty of dislocations and dislocation walls were easily observed. In addition, the microstructure of alloys subjected to annealed cold rolling revealed the formation of new fresh ${\alpha}-Mg$ grains in ${\beta}-Li$ phase due to the precipitation reaction. The mechanical properties and fracture modes of Mg-8Li-3Al-1Y alloys can be effectively tuned by different rolling processes.

• Current Optics and Photonics
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• v.3 no.1
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• pp.66-71
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• 2019

Application of liquid crystal (LC) materials to a flexible device is challenging because the bending of LC displays easily causes change in thickness of the LC layer and orientation of LCs, resulting in deterioration in a displayed image quality. In this work, we demonstrate a prototype device combining a flexible polymer substrate and an optically isotropic LC-polymer composite in which the device consists of interdigitated in-plane switching electrodes deposited on a flexible colorless polyimide substrate and the composite consisting of nano-sized LC droplets in a polymer matrix. The device can keep good electro-optic characteristics even when it is in a bending state because the LC orientation is not disturbed in both voltage-off and -on states. The proposed device shows a high potential to be applicable for future flexible LC devices.

• Biomolecules & Therapeutics
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• v.27 no.3
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• pp.302-310
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• 2019

Melanoma cells have been shown to respond to BRAF inhibitors; however, intrinsic and acquired resistance limits their clinical application. In this study, we performed RNA-Seq analysis with BRAF inhibitor-sensitive (A375P) and -resistant (A375P/Mdr with acquired resistance and SK-MEL-2 with intrinsic resistance) melanoma cell lines, to reveal the genes and pathways potentially involved in intrinsic and acquired resistance to BRAF inhibitors. A total of 546 differentially expressed genes (DEGs), including 239 up-regulated and 307 down-regulated genes, were identified in both intrinsic and acquired resistant cells. Gene ontology (GO) analysis revealed that the top 10 biological processes associated with these genes included angiogenesis, immune response, cell adhesion, antigen processing and presentation, extracellular matrix organization, osteoblast differentiation, collagen catabolic process, viral entry into host cell, cell migration, and positive regulation of protein kinase B signaling. In addition, using the PAN-THER GO classification system, we showed that the highest enriched GOs targeted by the 546 DEGs were responses to cellular processes (ontology: biological process), binding (ontology: molecular function), and cell subcellular localization (ontology: cellular component). Ingenuity pathway analysis (IPA) network analysis showed a network that was common to two BRAF inhibitorresistant cells. Taken together, the present study may provide a useful platform to further reveal biological processes associated with BRAF inhibitor resistance, and present areas for therapeutic tool development to overcome BRAF inhibitor resistance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.365-372
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• 2018

3D printing technology of construction field can be divided into structural materials, interior and exterior finishing materials, and is mainly done by extruding and adapting. Particularly when it is applied as an exterior materials, it is mainly applied to an unstructured exterior materials and high accuracy is required. The exterior materials can be used as a cement composite materials, it is suitable also for a additive type manufacturing, and the role of a redispersible polymer powder is important. But, high temperatures, redispersible polymer cement base material beget dehydration and micro crack of cement matrix. In this research, we developed a EVA, EVCL redispersible polymer cement base material applicable as a 3D printing exterior materials, confirmed density and strength characteristics for application as an exterior materials, a flame retardancy test for improving the fire resistance of buildings and confirmed its possibility. From the test result, developed EVCL redispersible polymer cement mortar showed good stability in high temperatures. These high temperature stability is caused by the ethylene-vinyl chloride binding. Thus, this result indicates that it is possible to fire resistant 3D printing interior and exterior finishing materials.

• Food Science of Animal Resources
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• v.39 no.4
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• pp.677-685
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• 2019

Five Leuconostoc strains (CM17, CM19, PM30, PM32, and PM36) previously isolated from Indian meat showed promising antimicrobial activity against food pathogens in screening assay. This study evaluates the efficacy of these isolates against Escherichia coli Microbial Type Culture Collection and Gene Bank (MTCC) 443 and Listeria monocytogenes (MTCC 657) in spinach leaves. Challenge studies were conducted by inoculating E. coli and L. monocytogenes at 6 to 7 $Log_{10}CFU/g$ of the leaves respectively and treating them with cell free supernatant (CFS) of 48 h cultures of the isolates. The samples were stored at $4^{\circ}C$ and analyzed over a period of 5 d. The study was conducted in triplicates and statistical analysis was carried out using one-way Anova. The counts of the pathogens did not increase over the 5 d period in the control samples, without any treatment. Whereas in the case of CFS treatments, significant reduction (p<0.05) was observed in both E. coli and L. monocytogenes from 1 to 5 d with all the 5 strains as compared to the control. The counts of Listeria dropped by 0.5 to 1 log by 5 d, with PM 36 showing the highest reduction (1 log). In the case of E. coli, 1.1 to 1.5 log reduction was observed by 5 d, with again PM 36 showing the highest reduction (1.5). The overall results indicate that the isolates (specifically PM36) not only showed efficacy in in vitro studies but are also proved to be effective in food matrix making them potential clean label antimicrobial alternatives for food application.