• Tunnel and Underground Space
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• v.29 no.3
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• pp.197-213
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• 2019

We simulated the fault reactivation experiment conducted at 'Main Fault' intersecting the low permeability clay formations of Mont Terri Underground Research Laboratory in Switzerland using TOUGH-FLAC simulator. The fluid flow along a fault was modelled with solid elements and governed by Darcy's law with the cubic law in TOUGH2, whereas the mechanical behavior of a single fault was represented by creating interface elements between two separating rock blocks in FLAC3D. We formulate the hydro-mechanical coupling relation of hydraulic aperture to consider the elastic fracture opening and failure-induced dilation for reproducing the abrupt changes in injection flow rate and monitoring pressure at fracture opening pressure. A parametric study was conducted to examine the effects of in-situ stress condition and fault deformation and strength parameters and to find the optimal parameter set to reproduce the field observations. In the best matching simulation, the fracture opening pressure and variations of injection flow rate and monitoring pressure showed good agreement with field experiment results, which suggests the capability of the numerical model to reasonably capture the fracture opening and propagation process. The model overestimated the fault displacement in shear direction and the range of reactivated zone, which was attributed to the progressive shear failures along the fault at high injection pressure. In the field experiment results, however, fracture tensile opening seems the dominant mechanism affecting the hydraulic aperture increase.

• Clean Technology
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• v.25 no.2
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• pp.123-128
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• 2019

$Bi_2MoO_6$ catalysts were successfully synthesized using ethylene glycol monomethyl ether (EGME), glycerol (GL), ethylene glycol (EG), and water as solvents by a conventional hydrothermal method. The synthesized catalysts were characterized by XRD, DRS, BET, SEM, and PL, and we also investigated the photocatalytic activity of these materials for the decomposition of Rhodamin B under visible light irradiation. The XRD results revealed the successful synthesis of 12-18 nm, well-crystallized ${\gamma}-Bi_2MoO_6$ crystals with an Aurivillius structure regardless of solvent. In addition, the $Bi_2MoO_6$ catalysts prepared below $140^{\circ}C$ showed an amorphous phase; however, those prepared above $160^{\circ}C$ showed well-crystallized ${\gamma}-Bi_2MoO_6$ crystals. All the catalysts have a similar absorption spectrum from the ultraviolet region up to the visible region less than 470 nm. This result suggests that all the $Bi_2MoO_6$ catalysts are potential visible-light-driven photocatalysts. The $Bi_2MoO_6$ catalysts prepared using EGME as a solvent showed the highest photocatalytic activity. In addition, the $Bi_2MoO_6$ catalysts prepared at $180^{\circ}C$ showed the highest photocatalytic activity. The PL peaks appeared at about 560 nm at all catalysts and the excitonic PL signal was proportional to the photocatalytic activity for the decomposition of Rhodamin B. This suggests that the stronger the PL intensity, the larger the amount of oxygen vacancies and defects, and the higher the photocatalytic activity.

• Korean Chemical Engineering Research
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• v.57 no.1
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• pp.111-117
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• 2019

This study proposed the fabrication and deposition of high purity crystalline $core-TiO_2/shell-Al_2O_3$ nanoparticles. Morphological properties of $core-TiO_2$ and coated $shell-Al_2O_3$ were confirmed by transmission electron microscope (TEM) and transmission electron microscope - energy dispersive spectroscopy (TEM-EDS). The electrical properties of the prepared $core-TiO_2/shell-Al_2O_3$ nanoparticles were evaluated by applying them to a working electrode of a Dye-Sensitized Solar Cell (DSSC). The particle size, growth rate and the main crystal structure of $core-TiO_2$ were analyzed through dynamic light scattering system (DLS), scanning electron microscope (SEM) and X-ray diffraction (XRD). The $core-TiO_2$, which has a particle size of 17.1 nm, a thin film thickness of $20.1{\mu}m$ and a main crystal structure of anatase, shows higher electrical efficiency than the conventional paste-based dye-sensitized solar cell (DSSC). In addition, the energy conversion efficiency (6.28%) of the dye-sensitized solar cell (DSSC) using the $core-TiO_2/shell-Al_2O_3$ nanoparticles selectively controlled to the working electrode is 26.1% higher than the energy conversion efficiency (4.99%) of the dye-sensitized solar cell (DSSC) using the conventional paste method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.6
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• pp.457-467
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• 2018

Currently, the regulation and rules for public surveying and the UCPs (Unified Control Points) adapts those of the triangulated traverse surveying. In addition, such regulations do not take account of the unique characteristics of GNSS (Global Navigation Satellite System) surveying, thus there are difficulties in field work and data processing afterwards. A detailed procesure of GNSS processing has not yet been described either, and the verification of accuracy does not follow the generic standards. In order to propose an appropriate procedure for field surveys, we processed a short session (30 minutes) based on the scenarios similar to actual situations. The reference network in Seoul was used to process the same data span for 3 days. The temporal variation during the day was evaluated as well. We analyzed the accuracy of the estimated coordinates depending on the parameterization of tropospheric delay, which was compared with the 24-hr static processing results. Estimating the tropospheric delay is advantageous for the accuracy and stability of the coordinates, resulting in about 5 mm and 10 mm of RMSE (Root Mean Squared Error) for horizontal and vertical components, respectively. Based on the test results, we propose a procedure to estimate the daily solution and then combine them to estimate the final solution by applying the minimum constraints (no-net-translation condition). It is necessary to develop a web-based processing system using a high-end softwares. Additionally, it is also required to standardize the ID of the public control points and the UCPs for the automatic GNSS processing.

• The Journal of the Korea Contents Association
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• v.19 no.1
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• pp.524-534
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• 2019

This study was to analyze the students' engagement in regular curriculum and extra-curriculum and its effects on learning outcomes in higher education. Students' engagement was analysed by high order learning, reflective and integrative learning, learning strategies, collaborative learning, discussions with diverse others, and high impact activities. To achieve the purpose of this study, 392 students joined in K-NSSE were participated. To analyze the datum, frequency analysis, ANOVA, correlation analysis, and regression analysis were performed using IBM SPSS 25.0 program. The following results were obtained. First, students' engagement was generally very low, especially in high impact activities which has an effect on the students' achievement. And compared to the students' engagement in the college of humanity and social science, the students' engagement in engineering college were very low. Learning outcomes were influenced by the high impact activities, high-order learning, and discussions with diverse others. So to reinforce students' engagement in learning process, this study proposed a curriculum-extracurriculum integrated system. And to improvement students' engagement, teaching and learning support programs including high impact activities. high order learning, and discussions with diverse others were proposed to be developed and operated.

• Journal of Microbiology and Biotechnology
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• v.29 no.4
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• pp.596-606
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• 2019

N-acyl-homoserine lactone quorum sensing (AHL-QS) has been shown to regulate many physiological behaviors in Serratia marcescens MG1. In the current study, the effects of AHL-QS on the biosynthesis of acid and neutral products by S. marcescens MG1 and its isogenic ${\Delta}swrI$ with or without supplementing exogenous N-hexanoyl-L-homoserine lactone ($C_6-HSL$) were systematically investigated. The results showed that swrI disruption resulted in rapid pH drops from 7.0 to 4.8, which could be restored to wild type by supplementing $C_6-HSL$. Furthermore, fermentation product analysis indicated that ${\Delta}swrI$ could lead to obvious accumulation for acidogenesis products such as lactic acid and succinic acid, especially excess acetic acid (2.27 g/l) produced at the early stage of fermentation, whereas solventogenesis products by ${\Delta}swrI$ appeared to noticeably decrease by an approximate 30% for acetoin during 32-48 h and by an approximate 20% for 2,3-butanediol during 24-40 h, when compared to those by wild type. Interestingly, the excess acetic acid produced could be removed in an AHL-QS-independent manner. Subsequently, quantitative real-time PCR was used to determine the mRNA expression levels of genes responsible for acidogenesis and solventogenesis and showed consistent results with those of product synthesis. Finally, by close examination of promoter regions of the analyzed genes, four putative luxI box-like motifs were found upstream of genes encoding acetyl-CoA synthase, lactate dehydrogenase, ${\alpha}$-acetolactate decarboxylase, and Lys-like regulator. The information from this study provides a novel insight into the roles played by AHL-QS in switching from acidogenesis to solventogenesis in S. marcescens MG1.

• 재활복지
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• v.20 no.1
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• pp.131-150
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• 2016

This study aims to compare global policies on ICT accessibility and to suggest possible solutions that help to enhance ICT accessibility for socially disadvantaged groups. The results indicated that related laws and standards in Korea are relatively well established than Asian countries' whereas they need improvements when compared to the US or the UK. Particularly, in spite of rapid development in information communication technology industry, incorporating the definition of newly developed technologies into existing laws related to ICT accessibility seemed slow that caused reluctancy of related parties to address accessibility issues the new technologies create. In addition, Korean government seems less effortful to develop policies and standards apart from web and mobile application accessibility. In order to resolve the problems, firstly, the period or process of enacting and amending laws can be shorten. Next, a government affiliated research institute can be established to do research and develop ICT accessibility related to user scenarios so that effective policies and standards could be readily provided. Even though other possible solutions can be suggested, what is more important than that is that any interested parties should sustainably make efforts to provide equal opportunities for the underserved populations.

• Journal of Digital Convergence
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• v.16 no.12
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• pp.459-466
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• 2018

Gendered innovations is a term used by policy makers and academics to refer the process of creating better research and development (R&D) for both men and women. In this paper, we analyze the literatures in image and speech signal processing that can be used in ICT, examine the importance of gendered innovations through case study. Therefore the latest domestic and foreign literature related to image and speech signal processing based on gender research is searched and a total of 9 papers are selected. In terms of gender analysis, research subjects, research environment, and research design are examined separately. Especially, through the case analysis of algorithms of the elderly voice signal processing, machine learning, machine translation technology, and facial gender recognition technology, we found that there is gender bias in existing algorithms, and which leads to gender analysis is required. We also propose a gendered innovations method integrating sex and gender analysis in algorithm development. Gendered innovations in ICT can contribute to the creation of new markets by developing products and services that reflect the needs of both men and women.

• Korean Chemical Engineering Research
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• v.57 no.2
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• pp.177-184
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• 2019

Non-fluorinated water repellent coating solutions were obtained using methyltrimethoxysilane (MTMS) and trimethylethoxysilane (TMES) as precursors. The solutions were spin-coated on a cold-rolled steel sheet and cured thermally to prepare water repellent coating films. During this process, the effect of molar ratio of TMES/MTMS was studied for the hydrophobic properties of the coating films. Hydrophobic properties of coating films were characterized using contact angle measurement, surface morphology analysis and infrared spectroscopy. When the molar ratio of TMES/MTMS was varied from 0 to 30, the contact angle of the un-coated cold-rolled steel sheet was $30^{\circ}$, whereas when the molar ratio of TMES/MTMS was 1, the contact angle increased to $104^{\circ}$ and water repellency was significantly improved. In the case of TMES/MTMS molar ratios of 10, 15, 25 and 30, the contact angles of coating films showed $109^{\circ}$, $114^{\circ}$, $117^{\circ}$ and $144^{\circ}$, respectively. At this time, the hydrophobicity of the coating films was improved by the increase of the surface roughness and the content of the methyl component at the coating surface. In particular, when the molar ratio of TMES/MTMS was 30, the overall surface roughness was greatly increased due to the presence of surface particles as well as the water repellency due to methyl groups of TMES, resulting in super hydrophobicity of $144^{\circ}$.

• International Area Studies Review
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• v.22 no.4
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• pp.145-166
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• 2018

This study is due to global competition, the wall between regions is disappearing, customer needs are diversified, and market and technology are rapidly changing. Future growth engines, the importance of convergence capabilities for industrial competitiveness is being emphasized more. Therefore, companies should seek innovative means to increase the efficiency of the company by establishing optimized global management environment and establishing direction and strategy for utilization of convergence technology by improving industrial competitiveness. Firms must adopt and utilize related new technologies by strengthening their convergence capabilities through dynamic capabilities that are internal resource bases for new product development and process innovation. Globalize markets and technologies can expect higher innovation performance when aligning strategic direction with formalized technology competencies held by the firm and incorporating the convergence capabilities needed for technological innovation into processes. The study focuses on the effects of market and technology orientation on technological innovation performance, whether dynamic and convergence capabilities affect technological innovation performance, and dynamic and convergence capabilities to mediate between market and technology orientation. For the study, we surveyed 51.4% of global and multinational corporations that are internationally active or headquartered overseas. Based on the previous studies, hypotheses were established and the collected data were analyzed through utilization path analysis and Sobel test.