• Geophysics and Geophysical Exploration
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• v.13 no.2
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• pp.137-143
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• 2010

An earthquake with local magnitude $(M_L)$ 3.7 on December 9, 2000 occurred offshore Yeongdeok area, South Korea. In case of applying Chang and Baag (2006) crustal velocity model, the epicenter is $36.4462^{\circ}N\;and\;129.9789^{\circ}E$, which belongs to the inside of the Korean Peninsula Continental Shelf. Although we use the modified model reducing crustal thickness of Chang and Baag (2006) model by 5 km considering the transition from continental crust to oceanic crust in the East Sea, the epicenter was little changed. We carried out the waveform inversion analysis to estimate focal depth and focal mechanism of this event. The focal depth is estimated to be 11 ~ 12 km. The seismic moment is estimated to be $1.0{\times}10^{15}N{\cdot}m$, and this value corresponds to the moment magnitude $(M_W)$ 3.9. The offshore Yeongdeok event including May 29, 2004 offshore Uljin one show typical thrust faulting, and the direction of P-axis is ESE-WNW. The moment magnitude estimated by the spectral analysis is 4.0, which is similar to that by the waveform inversion analysis. Average stress drop is estimated to be 3.4 MPa.

• Journal of Technology Innovation
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• v.28 no.4
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• pp.151-163
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• 2020

The routinized tasks in the post-COVID era are to be replaced by digital technologies, while there is a high possibility that digital transformation technologies and non-routinized tasks have strong complementarity. In particular, looking at the job composition within Korea's industries, the intensities of routinized works appear to be continuously rising. It suggests that the potential side effects on the labor market caused by the acceleration of digital transformation in the post-COVID era will be greater within Korean innovation system. With this background, this study aims to provide a conceptual framework for dealing with potential crises such as, job polarization and widening gaps between workers in terms of economic earnings, based on an in-depth understanding of the inherent properties of digital transformation that will lead to structural changes in our economic and social system. In particular, focusing on the interaction between digital transformation technology and learning in the post-COVID era, this study attempts to redefine the role of the innovation policy for making a successful transition to a new equilibrium state. In addition, this study examines the institutional conditions of the Korean innovation system which affect the creative learning activities of economic actors to draw policy implications for establishing future-oriented innovation policy. Based on these approaches, this study highlights the importance of coevolution between the skills demand and skills supply to spur inclusiveness of Korean innovation system in the post-COVID era.

• Journal of Energy Engineering
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• v.27 no.4
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• pp.80-85
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• 2018

Usable capacity is one of the most important parameters for evaluating the performance of an adsorbent for $CO_2$ capture from flue gas streams. In the pressure swing adsorption (PSA) process, the usable capacity is calculated as the difference between the quantity adsorbed in flue gas at high pressure (ca. 20 bar) and the quantity adsorbed at lower purge pressure (ca. 2 bar). In this paper, two stereo-types of metal-organic framework (MOF) were evaluated as an promising adsorbent for $CO_2$ capture: flexible structured MOF (MIL-53) and MOF possessing strong binding sites (MOF-74). The results showed that a total $CO_2$ capture capacity is strongly related to the specific surface area and heat of adsorption, revealing high uptake in MOF-74. However, the usable capacity was more pronounced in MIL-53 due to a structural transition.

• Korean Journal of Environment and Ecology
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• v.36 no.1
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• pp.72-86
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• 2022

This study was conducted to identify structural characteristics of the evergreen broad-leaved forests distributed in Hak-dong, Geojae island. For a survey, 52 sites were set up in areas with changes in the vegetation community or location environment where Cinnamomum yabunikkei, Neolitsea sericea, and Machilus thunbergii dominated or appeared in the canopy, sub-canopy, or shrub layer. The community classification with TWINSPAN identified the following communities: N. sericea-C. yabunikkei, C. yabunikkei-Camellia japonica, Ca. japonica, Quercus variabilis-Ca. japonica, Pinus thunbergii-Ca. japonica, Castanopsis sieboldii, P. thunbergii, and Platycarya strobilacea-Mallotus japonicus. Considering the result of the study that succession series of warm-temperate forest reflecting the latent natural vegetation is the transition of conifers and deciduous broad-leaved forest to evergreen broad-leaved forest, the communities predominated by the communities predominated by the communities predominated by P. thunbergii, Q. variabilis, and Pl. strobilacea are likely to transform into the evergreen forest predominated by N. sericea and C. yabunikkei. The sites where C. yabunikkei, N. sericea, and Castanopsis sieboldii are dominant in the canopy and sub-canopy layers are likely to maintain the status quo if there is no artificial disturbance. The relationship between the impact of the environmental factors and the vegetation distribution showed silt among the physical properties of the soil directly or indirectly affected it, which was judged to be due to the fact that it was located on a steep slope. The soil acidity (pH) was 5-5.84, electrical conductivity 0.047-0.139 dS/m, and organic matter content was 3.32-12.06%. Although there were differences by the colony, they were generally low.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.761-766
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• 2006

Polymer composite are increasingly considered as structural components for use in civil engineering, on account of their enhanced strength-to-weight ratios. Unsaturated polyester (UP) resin have been widely used for the matrix of composites such as FRP and polymer composite, due to its excellent adhesive. Polymer nanocomposites are new class of composites derived from the nano scale inorganic particles with dimensions typically in the range of 1 to 1000 nm that are dispersed in the polymer matrix homogeneously. Owing to the high aspect ratio of the fillers, mechanical, thermal, flame, retardant and barrier properties are enhanced without significant loss of clarity, toughness or impact strength. To prepare the MMT (Montmorillonite)-UP exfoliated nanocomposites, UP was mixed with MMT at $60^{\circ}C$ for 3 hours by using pan mixer. XRD (X-ray diffraction) pattern of the composites and TEM (Transmission Electron Micrographs) showed that the interlayer spacing of the modified MMT were exfoliated in polymer matrix. The mechanical properties also supported these findings, since in general, tensile strength, modulus with modified MMT were higher than those of the composites with unmodified MMT. The thermal stability of MMT-UP nanocomposite is better than that of pure UP, and its glass transition temperature is higher than that of pure UP. The polymer concrete made with MMT-UP nanocomposite has better mechanical properties than of pure UP. Therefore, it is suggested that strength and elastic modulus of polymer concrete was found to be positively tensile strength and tensile modulus of the MMT-UP nanocomposites.

• Korean Journal of Social Welfare Studies
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• v.41 no.3
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• pp.349-378
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• 2010

The Life-Course perspective is a theoretical orientation that views the life-course as the age structure embedded in social institutions and history and understands the life-course of individual and group in the contextual perspective. The life-course perspective studies were developed in Germany and North America. They study social and historical effects and the effect of institutions and the state on the life-course, the pathway of the work career and differences of labour outcomes, and the inequality that is developed in the life-course. In Korea, the life-course perspective studies were tried in various fields and cumulated. However, it didn't established as a theoretical orientation. For applying the life-course perspective to connect the individual life-course with social and historical event, I describe the historical location of individuals born between 1930 and 1979 and analyse the change of their transitions to adulthood exploratorily. On results, the extension of education made the structural change of their life-course, and in young cohort the timing of leaving school, entering workforce, marriage and childbirth was delayed and transitions were made in narrower spread. It means the standardization of the life-course as appears in modern society. The 1970s birth cohort has the differenciated life-course pattern, however I cannot verify that change because of the right censoring.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.6
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• pp.255-260
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• 2023

As demanding the detection of explosive molecules, it is required to develop rapidly and precisely responsive sensors with ultra-high sensitivity. Since two-dimensional semiconductors have an atomically thin body nature where mobile carriers accumulate, the abrupt modulation carrier in the thin body channel can be expected. To investigate the effectiveness of WSe₂ semiconductor materials as a detection material for TNT (Trinitrotoluene) explosives, WSe₂ was synthesized using thermal chemical vapor deposition, and afterward, WSe₂ FETs (Field Effect Transistors) were fabricated using standard photo-lithograph processes. Raman Spectrum and FT-IR (Fourier-transform infrared) spectroscopy reveal that the adsorption of TNT molecules induces the structural transition of WSe₂ crystalline. The electrical properties before and after adsorption of TNT molecules on the WSe₂ surface were compared; as -50 V was applied as the back gate bias, 0.02 μA was recorded in the bare state, and the drain current increased to 0.41 μA with a dropping 0.6% (w/v) TNT while maintaining the p-type behavior. Afterward, the electrical characteristics were additionally evaluated by comparing the carrier mobility, hysteresis, and on/off ratio. Consequently, the present report provides the milestone for developing ultra-sensitive sensors with rapid response and high precision.

• Journal of the Korean Regional Science Association
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• v.39 no.4
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• pp.33-51
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• 2023

This study aims to investigate the changes in the employment structure of occupational groups by job characteristics and analyze the factors influencing wage premiums in local labor markets from 2010 to 2020. This study's analysis involves three primary steps. First, the occupational characteristics data from the Korea Network for Occupations and Workers are subjected to an exploratory factor analysis, and then a non-routine task intensity index is calculated by each occupations. Then, we conduct an exploratory analysis of changes in the distribution of employment by occupation from 2010 to 2020 by combining data from the Population Census with data from the Korean Labor and Income Panel Study to construct individual-level and regional-level data. Thirdly, we employ a hierarchical linear model to examine the individual-level and regional-level factors influencing wage premiums. Since 2010, the proportion of employment in occupations requiring non-routine task has continued to rise and now dominates the metropolitan labor market. Moreover, agglomeration effects resulting from urbanization produce a substantial wage premium for wage workers in occupations requiring non-routine tasks. This study seeks to provide policy implications to mitigate inequality and polarization in local labor markets by empirically analyzing the transition of occupational structure and wage inequality in relation to the local labor market context.

• Information Systems Review
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• v.23 no.4
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• pp.23-43
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• 2021

Due to the recent transition to a non-face-to-face society, many organizations are quickly adapting to foster a smart work environment. The introduction of smart work does not simply end with incorporating ICT systems or solutions into business models since fundamental factors such as forms of employment and work styles need to be in line with the progression of technological advances. However, previous studies regarding smart work focus on improvements in productivity and efficiency from a technology acceptance perspective. Therefore, there is a lack of discussion on innovation resistance from employees and management control when ICT systems are introduced into the workplace. This study empirically analyzes the moderating effects of the organizational control method for employees and innovation resistance within a smart work environment. Additionally, this study aims to identify the structural characteristics that employees resist from an innovation resistance perspective when organizational innovation occurs. The empirical analysis of this study suggests that when smart work such as ICT technology is introduced into the workplace the level of innovation resistance decreases when there is a high level of relative advantage and self-efficacy, whereas the level of innovation resistance increases when there is a high level of use complexity. Moreover, this study revealed that the level of innovation resistance increases when the employees' behaviors were controlled. The results of this study intend to contribute to improving business management by suggesting factors worth considering when incorporating smart work into work places through a thorough case analysis.

• Journal of Nutrition and Health
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• v.57 no.1
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• pp.43-52
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• 2024

Purpose: Cancer is the leading cause of death in Koreans, with breast cancer being the most common among women. Breast cancer readily metastasizes, and the existing treatment processes impose a significant burden on patients. This study examined whether pomegranate-derived exosome-like nanovesicles (PNVs) have anti-cancer effects by inhibiting cell infiltration and metastasis while increasing apoptosis on breast cancer MDA-MB-231 cells. Methods: Initially, exosome-like nanovesicles were isolated from pomegranate using ultracentrifugation. Subsequently, the size range of these nanovesicles was confirmed using nanoparticle tracking analysis. The ability of breast cancer MDA-MB-231 cells to internalize these natural nanovesicles was assessed with flourescence microscope. The anti-cancer effects of the PNVs were confirmed by applying various concentrations of PNVs (10, 50, 100 ㎍/mL) to MDA-MB-231 cells and systematically assessing their impact on cell viability and migration. Results: The round shape of the lipid bilayer in the PNVs was confirmed, providing crucial insights into their structural properties. We demonstrate that PNVs-associated DiD dye can be efficiently internalized by the MDA-MB-231 cells. The data showed that the PNVs inhibited cell viability, invasion rates, and migration in MDA-MB-231 cells. In addition, PNVs were absorbed into the MDA-MB-231 cells, leading to an increased expression of apoptosis proteins, such as cleaved caspase-3 and phosphorus-JNK, in a concentration-dependent manner. Furthermore, a reduction in cell infiltration and decreased expression of the transition markers MMP-2 and MMP-9 proteins were observed. Conclusion: For the first time, this study suggests that PNVs may be useful in the prevention or treatment of breast cancer by inhibiting the infiltration and metastasis of MDA-MB-231 cells and inducing apoptosis.