• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.204-207
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• 2004

In this paper, mechanical properties of the high strength lightweight self-compacting concrete with simple mixed design method was investigated. Experimental tests were performed as such compressive strength, splitting tensile strength, modulus of elasticity and density of high strength lightweight self-compacting concrete. The 28 days compressive strength of high strength lightweight self-compacting concrete with the LC replacement ratio of $100\%$ reduces about $31\%$ but LF replacement ratio of $100\%$ increase about $20\%$ compared that of the control concrete. The structural efficiency of high strength lightweight self-compacting concrete increase with proportional to the replacement into of LF. The relationship between the splitting tensile strength and 28 days compressive strength can be represented by the equation $f_s=0.076f_{ck}+0.5582$. The modulus of elasticity was found to be lower than that of normal weight concrete, ranging form 24 to 33 GPa.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.75-82
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• 2020

This study was attempted to identify differences in depression and psychological emotions according to the degree of self-elasticity of college freshmen in COVID-19. The survey was conducted online from April 6 to 13, 2020, and the results were analyzed using a total of 220 copies of the survey data, excluding insufficient surveys. As a result of the analysis, compared to the case where the self-elasticity is below average, the psychological emotion caused by COVID-19 as well as the depression of new students is statistically significant in all emotions such as anxiety, irritability, helplessness, anger, fear, confusion, and distrust. It was found to be higher. Based on these results, several roles and coping strategies were suggested to help students recover and maintain their psychological stability and mental health.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.25 no.3
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• pp.150-159
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• 2012

Objective : The purpose of this study was to evaluate the effect of korean herbal cosmetics for facial skin elasticity. Methods : We recruited patients and divided them to cosmetics group and control group randomly. We provided korean herbal cosmetics to cosmetics group and subjects in cosmetics group applied the provided cosmetics for 4 weeks. Control group waited and applied cosmetics that had previously used for 4 weeks. We assessed all subjects in 0 week, 2 weeks and 4 weeks. Primary assessment instrument was moire topography photo scale. Second assessment instrument was skin moisture, oiliness and elasticity which assessed with skintouch system v1.0, detox/regeneration questionnaire score and self-evaluating facial wrinkle/looseness score. Result : Moire topography photo scale improved in cosmetics group than control group significantly. Skin moisture and elasticity assessed with skintouch system improved in cosmetics group than control group significantly while skin oiliness assessed with skintouch system have not improved significantly. Detox/regeneration questionnaire score and self-evaluating facial wrinkle/looseness score improved in cosmetics group than control group significantly. Conclusion : Korean herbal cosmetics application might be effective method for facial skin elasticity.

• Journal of Industrial Convergence
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• v.18 no.5
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• pp.54-61
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• 2020

The purpose of this study was to understand the effect of job stress of female caregivers working in home-based elderly welfare centers on turnover intentions and to understand the moderating effect of self-elasticity in these relationships. The subject of the study was a self-written questionnaire survey of 170 nursing care workers at 28 home-based elderly welfare centers in Seoul, and 150 copies were collected and 133 people were finally analyzed excluding 17 unscrupulous responses. As a result of the study, first, the average value of turnover intention was high in the group with low experience of female caregivers at home-based elderly welfare centers and the group without religion. Second, the higher the job stress of nursing care workers, the higher the intention of turnover. Third, there was a moderating effect of self-elasticity between the job stress and the of turnover of nursing care workers. Therefore, it was necessary to consider measures to prevent job stress of nursing caregivers and improve self-resilience.

• Computers and Concrete
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• v.28 no.5
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• pp.451-463
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• 2021

Inorganic basalt fiber (BF) is a novel sort of commercial concrete fiber which is made with basalt rocks. Previous studies have not sufficiently handled the behavior of self-compacted concrete, at elevated temperature, containing basalt fiber. Present endeavor covers experimental work to examine the characteristics of this material at high temperature considering different fiber content and applied temperature. Different tests were carried out to measure the mechanical properties such as compressive strength (fc), modulus of elasticity (E), Poisson's ratio, splitting tensile strength (fsplit), flexural strength (fflex), and slant shear strength (fslant) of HSC and hybrid concrete. Gene expression programming (GEP) was employed to propose new constitutive relationships depending on experimental data. It was noticed from the testing records that there is no remarkable effect of BF on the Poisson's ratio and modulus of elasticity of self-compacted concrete. The flexural strength of basalt fiber self-compacted concrete was not sensitive to temperature in comparison to other mechanical properties of concrete. Fiber volume fraction of 0.25% was found to be the optimum to some extend according to degradation of strength. The proposed GEP models were in good matching with the experimental results.

• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.4
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• pp.73-93
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• 2012

In recent years, service delivery systems employing a self-service approach have been rapidly spreading. Since a self-service system provides a lower product price, it attracts more customers. However, some system managers are still hesitant to accept a self-service system, because there is no systematic model to predict its performance. Therefore, this research attempts to provide a systematic and quantitative model to predict the performance of a self-service system, focused specifically on a self-service gas station. Under this model, the traditional queuing theory was adopted to describe the general self-service process, but it is also assumed that some changes occur in both the customer arrival rate and the service performance rate. In particular, the price elasticity was introduced to capture the change in the customer arrival rate, and the existence of learning effect and helpers were assumed to design the changed service performance rate. Under these assumptions, a simulation model for a self-service gas station is established, and three performance measurements, such as average number of customers, average waiting time, and Utilization are observed, depending on the changes in price difference and helper-operating time. In this research, the optimal operation strategy for price differentiation and helper-operating time is proposed in accordance with the level of the customer learning rate. Although this research confines the scope of the study to the self-service gas station model, the results of this research can be applied to any type of self-service system.

• Structural Engineering and Mechanics
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• v.46 no.2
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• pp.295-322
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• 2013

Steel fiber reinforced self-compacting concrete (SFRSCC) is a relatively new composite material which congregates the benefits of self-compacting concrete (SCC) technology with the profits derived from the fiber addition to a brittle cementitious matrix. Steel fibers improve many of the properties of SCC elements including tensile strength, toughness, energy absorption capacity and fracture toughness. Modification in the mix design of SCC may have a significant influence on the SFRSCC mechanical properties. Therefore, it is vital to investigate whether all of the assumed hypotheses for steel fiber reinforced concrete (SFRC) are also valid for SFRSCC structures. Although available research regarding the influence of steel fibers on the properties of SFRSCC is limited, this paper investigates material's mechanical properties. The present study includes: a) evaluation and comparison of the current analytical models used for estimating the mechanical properties of SFRSCC and SFRC, b) proposing new relationships for SFRSCC mixtures mechanical properties. The investigated mechanical properties are based on the available experimental results and include: compressive strength, modulus of elasticity, strain at peak compressive strength, tensile strength, and compressive and tensile stress-strain curves.

• Journal of Fashion Business
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• v.24 no.6
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• pp.120-134
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• 2020

Recently, the beauty industry has implemented personalized services based on skin big data. To increase competitiveness in the beauty industry, systematic data measurement and evaluation indicators are necessary to select data and obtain necessary knowledge. In response, this study sought to stably enhance the accuracy of skin diagnosis based on satisfaction and reliability. To this end, the research was conducted through focus group interviews (FGI), a case study of brands, and analysis of prior research results. In particular, as a result of analyzing keywords that classify skin types by brand, common survey items for skin types were oiliness and using moisturizer, cosmetic use and vascular of skin, external stimulus and blemish & freckles, facial wrinkle, outside activities, self-consciousness, and smoke. In additioin to the common questions of the preceding study and the brand survey items, the questions concerning complex skin types, seasonal change, facial color, wrinkles and elasticity were added, and the questions were presented in a total of 40 items. In particular, it suggested that skin measurement could be conducted by focusing on elasticity and pigmentation items by reflecting the results of prior research and the opinions of FGI, and based on this, a customized service with high satisfaction and high accuracy of beauty care based on this could be proposed. We hope that this study will facilitate active self-care by providing more satisfying skin stones and personalized cosmetics proposals, thus laying the foundation for the further development of the cosmetics industry.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.167-168
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• 2020

본 연구는 학업중단청소년 패널조사 5차년도 조사(2017년) 데이터를 활용하여 학업중단 청소년의 진로불안이 우울에 영향을 미치는 과정에서 외적 보호요인으로 작용하는 사회적 관계(부모애착, 또래애착)와 내적 보호요인으로 작용하는 자아탄력성의 매개효과를 검증하고자 한다.

• Review of Korea Contents Association
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• v.17 no.3
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• pp.26-32
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• 2019