• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.5
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• pp.273-278
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• 2019

In this study, a new simple method for the estimation of hyperelastic material properties by indentation tests is proposed. Among hyperelastic material models, the Yeoh model with three material properties ($C_{10}$, $C_{20}$, $C_{30}$) is adopted to describe the strain energy density in terms of strain invariants. Finite element simulations of the spherical indentation of hyperelastic materials of the Yeoh model with different material properties are performed to establish a database of indentation force-displacement curves. The indentation force-displacement curves are fitted by cubic polynomials, which are approximated as a product of third-order polynomials of ($C_{10}$, $C_{20}$, $C_{30}$). A regression analysis is conducted to determine the coefficients of the equations for the indentation force-displacement curve approximations. A regression equation is used to estimate the hyperelastic material properties. The present method is verified by comparing the estimated material properties with true values.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.4
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• pp.191-212
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• 2020

In this study, a study on the cooperative system of the Chungnam Library's joint preservation data center and a plan for the construction of the use service was proposed based on the analysis of the current status of the preservation library of the Chungcheongnam-do public library. In order to establish a cooperative plan for the joint preservation archive and to promote the provision of services, the current state of the collection of 62 public libraries in Chungnam-do and the status of the preservation archives that are operating separately were identified. As a result of the study, it was found that all matters related to the operation of the joint preservation archive should be made through agreements or consultations between the participants, and the operation of the joint preservation archive should also be made under a systematic cooperation system between the participants. To this end, it is necessary to establish a cooperative system for the Chungnam Library Joint Preservation Archives, and to form and operate the Joint Preservation Archives Steering Committee, a consultative body (cooperation network). In addition, all matters related to the operation of the Joint Preservation Archive, such as transfer criteria, must be regulated and implemented through consultation with the Joint Preservation Archive Steering Committee.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.603-613
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• 2021

As a core policy for achieving the goal of reducing greenhouse gas emissions in the building sector, Korea has enforced the mandatory certification of zero energy buildings for new public buildings from 2020. This study suggests energy-saving technologies and economic factors that building officials can refer to for decision-making on the implementation of zero energy buildings. For this study, the construction cost for the energy item of a building was analyzed by collecting the building energy efficiency level certification data and detailed construction cost statement data from public institutions for the last three years. Based on the building energy efficiency certification data, each energy item of the baseline building was derived, and the energy performance of the zero energy building was derived through repetitive simulations by gradually increasing the energy performance value of the baseline building. By applying the analyzed construction cost, the construction cost for each energy item of the baseline and zero energy buildings was derived. As a result, the lighting equipment contributed up to 10.5% energy savings, and the increase in construction cost of the cooling and heating system was at least 9.1%.

• Tunnel and Underground Space
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• v.31 no.1
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• pp.10-24
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• 2021

Rock mass classification for construction of underground facilities is essential to secure their stabilities. Therefore, the reliable values for rock mass classification from the precise information on rock discontinuities are most important factors, because rock mass discontinuities can affect exclusively on the physical and mechanical properties of rock mass. The conventional classification operation for rock mass has been usually performed by hand mapping. However, there have been many issues for its precision and reliability; for instance, in large-scale survey area for regional geological survey, or rock mass classification operation by non-professional engineers. For these reasons, automated rock mass classification using LiDAR becomes popular for obtaining the quick and precise information. But there are several suggested algorithms for analyzing the rock mass discontinuities from point cloud data by LiDAR scanning, and it is known that the different algorithm gives usually different solution. Also, it is not simple to obtain the exact same value to hand mapping. In this paper, several discontinuity extract algorithms have been explained, and their processes for extracting rock mass discontinuities have been simulated for real rock bench. The application process for several algorithms is anticipated to be a good reference for future researches on extracting rock mass discontinuities from digital point cloud data by laser scanner, such as LiDAR.

• Applied Chemistry for Engineering
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• v.22 no.6
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• pp.672-678
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• 2011

In this work, carbon fibers were electrolessly Ni-plated in order to investigate the effect of metal plating on the electromagnetic shielding effectiveness (EMI-SE) of Ni-coated carbon fibers-reinforced epoxy matrix composites. The surfaces of carbon fibers were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Electric resistance of the composites was tested using a 4-point-probe electric resistivity tester. The EMI-SE of the composites was evaluated by means of the reflection and adsorption methods. From the results, it was found that the EMI-SE of the composites enhanced with increasing Ni plating time and content. In high frequency region, the EMI-SE didn't show further increasing with high Ni content (Ni-CF 10 min) compared to the Ni-CF 5 min sample. In conclusion, Ni content on the carbon fibers can be a key factor to determine the EMI-SE of the composites, but there can be an optimized metal content at a specific electromagnetic frequency region in this system.

• 한국사회정책
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• v.23 no.2
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• pp.83-112
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• 2016

Increase of immigrants in Korean society means that ethnic and cultural diversity witnessed in Western immigration countries is also appearing in overall Korean society. The purpose of this study is to suggest policy directions which fit multicultural society in the future by comparing and analyzing the difference in the recognition of multiculturalism between Koreans and immigrants. As the result of empirical analysis, it turned out that there is difference in recognition between Koreans and immigrants, for which different policy directions are required. First, it was contact experience that decided Koreans' multicultural attitudes. High level of influence of contact experience means that although Koreans take multicultural society as granted, they actually have low level of contact experience with immigrants, which requires policy tools to convert actual strengthened contact experience into positive directions. Second, in the case of immigrants, the less they recognize discrimination and the more bias is fortified, the more they accept multiculturalism as a threat. This exhibits their dual sense of identity in which they recognize themselves as foreigners toward Koreans but they distinguish themselves from other foreigners. Thus, assimilation to Korean society is not deemed to be the only alternative and Korean society needs to practice genuine multiculturalism to strengthen immigrants' ethnic identity. Study also conducted in-depth discussions on the implications of above results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.539-547
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• 2021

This study was conducted to identify the effects of knowledge of Advance Directives (AD) and the patient's perception of a peaceful death on their attitude toward the withdrawal of life-sustaining treatment and to provide basic data for the development of a nursing intervention program for activating self-determination in the withdrawal of life-sustaining support of patients. The subjects were 167 adult cancer patients who received outpatient or inpatient treatment, from September 15, 2019, to March 30, 2020. The data was analyzed by mean, standard deviation, t-test, ANOVA, Pearson's correlation coefficient, and multiple regression by using SPSS 21.0. From the results, it was observed that the knowledge of AD was 8.87±2.46 out of 12, perception of a peaceful death was 2.87±0.42 out of 4, and attitude toward withdrawal of life-sustaining treatment was 3.46±0.49 out of 5. There was a positive correlation between knowledge of AD, perception of a peaceful death, and their attitude toward withdrawal of life-sustaining treatment. The influencing variables were the knowledge of AD, perception of a peaceful death, discussion with family on withdrawal of life-sustaining treatment, and explanation power was 16.0% (F=10.355, p<.001). Therefore, it is necessary to develop a program that would improve the perception of a peaceful death, increase the knowledge of AD to improve the patients' attitude toward the withdrawal of life-sustaining treatment. An intervention to assist a discussion between the patients and their families in advance would also be useful.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.13-19
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• 2021

This study examined the effects of stacking faults on the thermoelectric properties for n-type SiC semiconductors. Porous SiC semiconductors with 30~42 % porosity were fabricated by the heat treatment of pressed ��-SiC powder compacts at 1600~2100 ℃ for 20~120 min in an N2 atmosphere. XRD was performed to examine the stacking faults, lattice strain, and precise lattice parameters of the specimens. The porosity and surface area were analyzed, and SEM, TEM, and HRTEM were carried out to examine the microstructure. The electrical conductivity and the Seebeck coefficient were measured at 550~900 ℃ in an Ar atmosphere. The electrical conductivity increased with increasing heat treatment temperature and time, which might be due to an increase in carrier concentration and improvement in grain-to-grain connectivity. The Seebeck coefficients were negative due to nitrogen behaving as a donor, and their absolute values also increased with increasing heat treatment temperature and time. This might be due to a decrease in stacking fault density, i.e., a decrease in stacking fault density accompanied by grain growth and crystallite growth must have increased the phonon mean free path, enhancing the phonon-drag effect, leading to a larger Seebeck coefficient.

• Knowledge Management Research
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• v.22 no.1
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• pp.39-56
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• 2021

In the current knowledge society, mobile devices have become a useful tool for performing work. In the context of COVID-19 which has made digital transformation inevitable, the importance of mobile work behaviors - performing work tasks through mobile devices - is further highlighted. Drawing from the behavioral immune system theory and cognitive appraisal theory of emotions, this study proposes that individual workers' concern about getting infected by COVID-19 will be negatively related to job satisfaction but positively related to mobile work behaviors. We further propose that leaders' communality and agency trait will be positively related to both job satisfaction and the increase of mobile work behaviors. Analyses of a matched dataset comprising survey data and mobile application usage data from 407 workers showed that their leaders' agency and communality were significantly related to the workers' job satisfaction. However, their mobile productivity was significantly related only to the communality of their leaders. The results of this study will provide useful theoretical and practical implications for researchers and managers who aim to understand and promote the technology adoption and knowledge productivity of workers in a pandemic situation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.46 no.4
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• pp.415-424
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• 2020

In the present study, we have refined gomisin N, which represents activity in the proliferation of dermal papilla cells (HFDPCs) from the fruit of Schisandra chinensis (S. chinensis), and have identified optimal extraction conditions for obtaining extracts with high content of gomisin N. The activity of the extracts and fractions was evaluated, and the results indicated approximately 29% proliferation activity in the group treated with 1 ㎍/mL of n-hexane fraction. Column chromatography was used to assess the active ingredient in the n-hexane fraction, and two compounds, namely gomisin N(1) and schisandrin(2), were isolated and identified. When the HFDPCs proliferation activity was tested for the isolated compounds, gomisin N exhibited ≥ 20% proliferation activity. Thus, via response surface methodology (RSM), the optimum extraction conditions to obtain the maximum level of gomisin N from the fruit of S. chinensis were determined, where ethanol proportion, extraction time, and extraction temperature were used as the independent variables. The results revealed coefficient of determination ≥ 0.95 and p-value ≤ 0.05, which confirmed the fit of the model. The optimum extraction conditions to achieve the maximum content of gomisin N were as follows: ethanol proportion 83.8%, extraction temperature 80 ℃, and extraction time 8.7 h. The content of gomisin N using these conditions was predicted as 378,300 ppm, and a mean value close to the predicted value (376,884 ppm) was obtained while validating the aforementioned conditions.