• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.295-302
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• 2011

Ubiquitous is an information communication environment which peoples could connect on network without being conscious of the network and computer condition at anytime and anywhere. Presently, advanced technology, digital cities and eco-friendly cities using Ubiquitous technology are being focused through out the world. As recent information industry and communication technology have developed remarkably, studies on intelligent structures and structural maintenance methods by combining a general idea of connecting all objects on network by interpolating computers which is called Ubiquitous Computing, and USN(Ubiquitous Sensor Network) are being attempted. In this paper, a basic experiment on penetration of RF(Radio Frequency) sensor nodes using an experimental sample setting concrete and reinforcing bar as variables is studied to estimate the possibility of applying wireless sensor networks in structures. The spring of reinforcing bars, concrete thickness, intensity of radio frequency were set up as variables, transmitting and receiving distance were checked vertically and horizontally. Moreover, Spectrum Analyzer was used for checking the magnitude of the frequency used in order to measure the reduction of radio wave exactly. The radio wave reduction was numerically analyzed, and the influence of the wavelength was analysed as well. As a result, the penetration depth in concrete without reinforcing bars was 45cm, and in reinforced concretes which reinforcing bars placed at spacing of 5cm and 15cm, the penetration depth were 37cm and 45cm each. No influence on radio wave penetration depth were found when the spacing of reinforcing bars in the reinforced concrete structures becomes over 15cm.

• Management & Information Systems Review
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• v.31 no.4
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• pp.33-56
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• 2012

The purposes of this paper are analysed the relationship between environmental regulation and financial performance in Korea. The financial performance of listed companies and Outside Auditing firms was evaluated by logistic regression. First, R&D investment is proportionally correlated with the ability to comply with environmental regulations. It can be explained increase of investment in R&D causes enhancement of compliance of environmental regulations with development of environmental technology. Second, statistical significance is not observed between financial aspects such as current ratio, debt-to-equity ratio, cash flow, and operating profit margin and the ability to comply with environmental regulations. It indicates high financial performance could not directly lead investment for the ability of that. Third, in terms of structural aspects, firm size and employees have a reliable correlation with compliance with environmental regulations due to high attention of larger firms for PR, and IR, while capital intensity and gravity, and exports do not. Finally, violation of environmental regulations is not affect by the controlling shareholder ownership.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.1
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• pp.11-20
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• 2008

In probabilistic seismic analysis of nonlinear structural system, dynamic analysis is performed to obtain the distribution of the response estimate using input ground motion time histories which correspond to a given seismic hazard level. This study investigates the differences in the distribution of the responses and the failure probability according to input ground motion models. Two types of input ground motion models are considered: real earthquake records scaled to specified intensity level and artificial input ground motion fitted to design response spectrum. Simulation results fir a nonlinear SDOF system demonstrate that the spectrum matched input ground motion produces larger failure probability than those of scaled input ground motion due to biased responses. Such tendency is more remarkable in the site of soft soil conditions. Analysis results show that such difference of failure probability is due to the conservative estimation of design response spectrum in the range of long period of ground motion.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.82-93
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• 2019

Fashion cannot encourage co-consumption with other people as a personal item, but it can lead to new consumer needs if fashion sharing service can professionally replace the time and cost of purchasing and managing goods. The purpose of this study is to empirically investigate the factors influencing the acceptance of fashion-sharing services based on the integration theory of user acceptance and utilization (UTAUT), and to discuss the virtuous cycle and sustainability pursuit of resources through the activation of the sharing. In this study, the research model for the acceptance of fashion sharing applications is schematized, and the survey was conducted 300 women aged 20~49 years. The screens of 'Project Anne', a representative fashion sharing service in Korea, were provided as a visual data. Reliability analysis, correlation analysis, confirmatory factor analysis, structural equation analysis, and multiple group analysis were performed using SPSS 23.0 and AMOS 22.0 statistical package for statistical analysis. As a result, efficiency and social influence positively influenced behavioral intention to use, and age has found that efficiency and social influences modulate the intensity of behavioral intention to use. Therefore, for the consumer acceptance and activation of fashion sharing services, marketing activities emphasizing efficiency and strengthening social influence factors are essential. Also, it is necessary to maintain the existing target group, 30~40s, and also construct additional products and price services for the 20s. This study is of academic significance in presenting basic data for empirical research on consumer acceptance of fashion sharing, and suggests a study on the influence relationship among user experience components for real users in the future.

• Korean Journal of Environment and Ecology
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• v.36 no.5
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• pp.535-549
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• 2022

Damage to forests, such as broken or falling trees, has increased due to the increased intensity and frequency of abnormal climate events, such as strong winds and heavy rains. However, it is difficult to respond to them in advance based on prediction since structural defects such as cavities and bumps inside trees are difficult to identify with a visual inspection. Non-invasive sonic tomography (SoT) is a method of estimating internal defects while minimizing physical damage to trees. Although SoT is effective in diagnosing internal defects, its accuracy varies depending on the species. Therefore, it is necessary to analyze the reliability of its measurement results before applying it in the field. In this study, we measured internal defects in wood by cross-applying destructive resistance micro drilling on old Pinus densifloraSiebold & Zucc. and Ginkgo bilobaL., which are representative tree species in Korea, to verify the reliability of SoT and compared the evaluation results. The t-test for the mean values of the defect measurement between the two groups showed no statistically significant difference in pine trees and some difference in ginkgo trees. Linear regression analysis results showed a positive correlation with an increase in defects in SoT images when the defects in the drill resistance graph increased in both species.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1455-1465
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• 2021

The purpose of this research was to investigate the mediating effect of grit on the relationship between leisure sport participation and academic efficacy/peer relationship of senior elementary school students. For this purpose, we analyzed the data of 2,437 fourth-grade elementary school students derived from the 2nd years of the Korean Children and Panel Survey(KCYPS, 2018). Structural Equation Modelling(SEM) were conducted through PASW Statistics 18 and AMOS Graphics 18 programs. The main results were as follows. First, grit fully mediated the association between leisure sport participation and academic efficacy. Second, the relationship between leisure sport participation and peer relationship was partially mediated by grit. The conclusion we could draw from these results was that participating in leisure sport with sweating intensity had a positive effect on the grit of senior elementary school students, which in turn had a positive effect on academic efficacy and peer relationship. Finally, we discussed the implications of leisure sport participation for senior elementary school students.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.174-174
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• 2000

A strong antiferromagnetic coupling in Fe/Si multilayered films (MLF) had been recently discovered and much consideration has been given to whether the coupling in the Fe/Si MLF system has the same origin as the metal/metal MLF. Nevertheless, the nature of the interfacial ron silicide is still controversial. On one hand, a metal/ semiconductor structure was suggested with a narrow band-gap semiconducting $\varepsilon$-FeSi spacer that mediates the coupling. However, some features show that the nature of coupling can be well understood in terms of the conventional metal/metal multilayered system. It is well known that both magneto-optical (MO) and optical properties of a metal depend strongly on their electronic structure that is also correlated with the atomic and chemical ordering. In this study, the nature of the interfacial regions is the Fe/Si multilayers has been investigated by the experimental and computer-simulated MO and optical spectroscopies. The Fe/Si MLF were prepared by rf-sputtering onto glass substrates at room temperature with the number of repetition N=50. The thickness of Fe sublayer was fixed at 3.0nm while the Si sublayer thickness was varied from 1.0 to 2.0 nm. The topmost layer of all the Fe/Si MLF is Fe. In order to carry out the computer simulations, the information on the MO and optical parameters of the materials that may constitute a real multilayered structure should be known in advance. For this purpose, we also prepared Fe, Si, FeSi2 and FeSi samples. The structural characterization of Fe/Si MLF was performed by low- and high -angle x-ray diffraction with a Cu-K$\alpha$ radiation and by transmission electron microscopy. A bulk $\varepsilon$-FeSi was also investigated. The MO and optical properties were measured at room temperature in the 1.0-4.7 eV energy range. The theoretical simulations of MO and optical properties for the Fe/Si MLF were performed by solving exactly a multireflection problem using the scattering matrix approach assuming various stoichiometries of a nonmagnetic spacer separating the antiferromagnetically coupled Fe layers. The simulated spectra of a model structure of FeSi2 or $\varepsilon$-FeSi as the spacer turned out to fail in explaining the experimental spectra of the Fe/Si MLF in both intensity and shape. Thus, the decisive disagreement between experimental and simulated MO and optical properties ruled out the hypothesis of FeSi2 and $\varepsilon$-FeSi as the nonmagnetic spacer. By supposing the spontaneous formation of a metallic ζ-FeSi, a reasonable agreement between experimental and simulated MO and optical spectra was obtained.

• 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.

• Journal of Life Science
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• v.19 no.9
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• pp.1218-1225
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• 2009

Difractose anhydrides (DFAs) is studied as a sweetener for diabetics because of its structural property. DFAs have four types: DFA I, III, IV (degradation of levan) and V (degradation of inulin). Especially, DFA IV has been shown to enhance the absorption of calcium in experiments using rats. Levan fructotransferase is an enzyme for producing di-d-fructose-2,6':6,2-dianhydride (DFA IV). To identify structural characterization, we purified wild-type and mutants (D63A, D195N and N85S) of levan fructotransferase (LFTase) from Microbacterium sp. AL-210. These proteins were purified to apparent homogeneity by Ni-NTA affinity column, Q-sepharose ion exchange and gel filtration chromatography and detected by SDS-PAGE. They were also analyzed by circular dichroism (CD) measurements, JNET secondary structure prediction, activity measurements at various temperatures, and pH analysis. The optimum pH for the enzyme-catalyzed reaction was pH 7.5 and optimum temperature was observed at $55^{\circ}C$. Along with wild-type LFTase, mutants were analyzed by CD measurement, fluorescence analysis and differential scanning calorimetry (DSC). N85S showed less $\alpha$-helix and more $\beta$ strand than others. Also, N85S showed almost the same curve as wild-type in their steady-state fluorescence spectra, whereas mutant D63A and D195N showed higher intensity than wild-type. The amino acid sequence of wild-type LFTase was compared to the sequences of exo-inulinase from Aspergillus awamori, a plant fructan 1-exohydrolase from Cichorium intybus, and Thermotogo maritime (Tm) invertase and showed a high identity with Exo-inulinase from Aspergillus awamori.

• Korean journal of food and cookery science
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• v.26 no.6
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• pp.872-886
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• 2010

Six kinds of sunsik containing different contents of brown rice(BR; 20, 30, and 50%) were prepared and subjected to various processing conditions(with or without roasting at $200^{\circ}C$ for 20 min e.g., designated as RBR50 or BR50) to assess their functionality as ready-to-eat foods. They were also assessed for their nutritional and sensory properties and oxidative stability. Dietary fiber contents were proportionate to the levels of added BR. Protein was highest in RBR50 (p<0.001), which also had the highest amounts of free and structural amino acids. The amount of free amino acids tended to increase with roasting, although most amino acids were present in structural form. Oleic acid and linoleic acid were the predominant fatty acids in all prepared sunsik, and RBR50 presented noticeably higher peroxidability index due to its higher amount of linoleic acid(p<0.05). Nevertheless, RBR50 showed good oxidative stability; this phenomenon was observed in all sunsik with roasted BR but not in those with non-roasted BR. It is implied that potential antioxidants might have been newly formed or converted from their precursors while BR was roasted. Roasting process also had an impact on the sensory properties of sunsik, e.g., sunsik with added roasted BR showed lower dissolution and darker color intensity compared to its counterpart sunsik.