• Toxicological Research
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• v.6 no.2
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• pp.205-213
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• 1990

The regulation of neurotoxicants has usually been based upon setting reference doses by dividing a no observed adverse effect level (NOAEL) by uncertainty factors that theoretically account for interspecies and intraspecies extraploation of experimental results in animals to humans. Recently, we have proposed a four-step alternative procedure which provides quantitative estimates of risk as a function of dose. The first step is to establish a mathematical relationship between a biological effect or biomarker and the dose of chemical administered. The second step is to determine the distribution (variability) of individual measurements of biological effects or their biomarkers about the dose response curve. The third step is to define an adverse or abnormal level of a biological effect or biomarker in an untreated population. The fourth and final step is to combine the information from the first three steps to estimate the risk (proportion of individuals exceeding on adverse or abnormal level of a biological effect or biomarker) as a function of dose. The primary purpose of this report is to enhance the certainty of the first step of this procedure by improving our understanding of the relationship between a biomarker and dose of administered chemical. Several factors which need to be considered include: 1) the pharmacokinetics of the parent chemical, 2) the target tissue concentrations of the parent chemical or its bioactivated proximate toxicant, 3) the uptake kinetics of the parent chemical or metabolite into the target cell(s) and/or membrane interactions, and 4) the interaction of the chemical or metabolite with presumed receptor site(s). Because these theoretical factors each contain a saturable step due to definitive amounts of required enzyme, reuptake or receptor site(s), a nonlinear, saturable dose-response curve would be predicted. In order to exemplify this process, effects of the neurotoxicant, methlenedioxymethamphetamine (MDMA), were reviewed and analyzed. Our results and those of others indicate that: 1) peak concentrations of MDMA and metabolites are ochieved in rat brain by 30 min and are negligible by 24 hr, 2) a metabolite of MDMA is probably responsible for its neurotoxic effects, and 3) pretreatment with monoamine uptake blockers prevents MDMA neurotoxicity. When data generated from rats administerde MDMA were plotted as bilolgical effect (decreases in hippocampal serotonin concentrations) versus dose, a saturation curve best described the observed relationship. These results support the hypothesis that at least one saturable step is involved in MDMA neurotoxicity. We conclude that the mathematical relationship between biological effect and dose of MDMA, the first step of our quantitative neurotoxicity risk assessment procedure, should reflect this biological model information generated from the whole of the dose-response curve.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.573-586
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• 2016

This study attempted to look into the effects of the job environment and job esteem on job satisfaction in the field of skin beauticians. To achieve this, a survey of their characteristics, job environment, job esteem and job satisfaction was carried out on 470 women in their 20s~50s working at skin care shops in the Seoul and Gyeonggi areas. First, it was found that the effects of the working environment on their vocational satisfaction, sense of belonging, level of contribution, wages and welfare, which are sub-factors of job satisfaction, are relatively high. This result shows that it is important to ensure proper resting facilities and resting areas. Second, it was shown that the higher the social evaluation, self-(implicit) assessment, future value, and self-fulfillment orientation, the higher the sub-factors of job satisfaction. This means that it is important to treat skin beauticians as professionals in order to improve their social recognition. The sub-factors of job environment-working conditions, organizational environment and job stability, and sub-factors of job environment-social evaluation, self(intrinsic) evaluation, future value and self-achievement orientation, had a major effect on the sub-factors of job satisfaction, respectively. Together with the general improvement in the sub-factors of job environment, the future value, as well as social evaluation, self(intrinsic) evaluation and self-achievement orientation, which together constituted the current value of job esteem, were the major factors affecting job satisfaction. Consequently, this study hopes to contribute to the development of the skin beauty industry by providing basic data on personnel management for skin care managers to improve skin beauticians' job satisfaction.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.459-467
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• 2016

This study was conducted to evaluate and identify what factors influence the satisfaction of the users for the fast-growing social network game based on the mobile. To this end, we looked around the variable product characteristic factor, quality and the consumer characteristic factor, user self-determination. Also we surveyed 211 male and female college students. The first finding was that all the sub-factors of the quality factor had positive effects on the satisfaction of the mobile social network games. The second finding was that all the sub-factors of the self-determination factor had positive effects on the satisfaction of the mobile social network games. The third finding was that only the sub-factors of quality had positive relative effects on the satisfaction of the mobile social network games, in the order of playfulness, usability, functionality from the most to the least. The findings of this study are expected to offer meaningful and practical suggestions for the development of high quality game contents for the user convenience, as well as the academic significance, the expansion of game-related area of research through the break from the traditional research trends, technology and engineering point of view and from the PC-based online game.

• Journal of Digital Convergence
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• v.12 no.5
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• pp.213-220
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• 2014

The purpose of this present study is to empirically analyze the variables affecting socio-economic performance of social enterprises. For this purpose of 107 enterprises, located in Seoul, was performed under the hypothesis that the authentication properties (authentication type, authentication year) of social enterprises will affect the socio-economic performance. The analysis showed that first; authentication type among the characteristics of social enterprises showed significant effects on the social performance. Second, authentication year among the characteristics of social enterprises showed significant effects on the economic performances. In addition, since the job-creating type showed higher social performance, it would be desirable to raise the certification rate of this type in the future. The analysis implied that longer the years of accreditation, the greater positive effects on the socio-economic performance of social enterprises was shown. Therefore, the present study suggest the need to diversify support policies according to the number of authentication years in order to secure sustainability by maximizing the socio-economic performance of social enterprise because the monolithic support is not very effective for continued growth and self-reliance of social enterprises.

• Journal of Digital Convergence
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• v.18 no.8
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• pp.133-149
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• 2020

The purpose of this study was to investigate the effect of perceived risk on continuous usage intention of Internet primary banks and to verify moderating effects of acceptance factors affecting customers' acceptance of Internet primary banks on the relationship between perceived risk and continuous usage intention. The study aims to find ways to cope with perceived risk and strategic measures of intention in order to increase the intention to continuous usage intention of Internet primary banks. For the analysis, interaction effect were conducted among a total of 457 surveys. As a results, First, perceived risks, acceptance factors and continuous usage intention of the customers of Internet primary banks were significantly correlated. Second, the types of perceived risks which have a significant effect on continued usage intention of Internet primary banks were found to be perceived financial and functional risks. Third, respect to moderating effects of moderator variables, usefulness was found to have a significant moderating effect on the relationship between perceived security risk and continuous usage intention. In addition, ease of use was shown to have a significant moderating effect on the relationship between each type of perceived risks and continuous usage intention. This study attempted to explore and seek strategies to reduce perceived risks and strategic plans for acceptance factors to increase continuous usage intention of Internet primary banks.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.367-380
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• 2020

Recently, Korea's economy is facing a difficult economic situation due to sluggish domestic demand, low corporate investment and a cliff in youth employment. In order to overcome this problem and turn the economy into a virtuous circle, the government has introduced and implemented various economic policies. In this study, the effects of the corporate accumulated earnings tax system included in the 2014 tax code revision were to be verified. The validity of the business income was verified and analyzed using the financial data of the entity as to whether the income of the entity was being circulated to household income. First, validating the validity of whether the income tax on non-current income affects the level of an entity's investment, the results showed significant negative effects at a significant level of 5 per cent. Second, the analysis of whether the return tax on corporate income is affecting management decisions that increase the level of dividends for an entity has identified a metaphorical positive relationship. Third, it was confirmed that the income tax on uncurrency income does not have a significant effect on the increase in wages for workers. The result is presumed to be the main reason for the increased uncertainty in the economy and business environment.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.742-748
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• 1998

Experiments have been conducted to investigate synergistic effects and mechanisms of the Alaskan subbituminous coal/polypropylene (PP). Coliquefaction of coal/PP gave the synergistic effect in yields by 17% compared to independent liquefactions of coal or PP at $430^{\circ}C$. To analyse coliquefaction mechanisms, the second and zeroth order kinetic models were developed for coal and PP conversions respectively. When the models were simulated to fit coliquefaction results, those represented results successfully with the correlation coefficient of 0.99. The amount of tetralin needed to liquefy unit mass of coa 1(${\beta}$) was also calculated using the developed model. According to the calculated results, $\beta$ increased from 0.4 to 1.0 as the coliquefaction temperature increased from $410^{\circ}C$ to $470^{\circ}C$. This indicated that tetralin lowered the molecular weight of oil produced, and this phenomenon was recognized by the GPC analyses. Furthermore, it was found that tetralin prohibited the liquefaction of PP when coal was not added. On the other hand, tetralin was believed to act as a hydrogen-donor solvent to coal rather than prohibit PP liquefaction during coliquefaction. Therefore, the liquefaction rate of PP increases and synergistic effects in oil yields are mainly due to the increase in PP liquefaction during coal/PP coliquefaction.

• Journal of Distribution Science
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• v.12 no.8
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• pp.123-132
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• 2014

Purpose - Recently, Korean companies have been struggling to perform well in the larger smartphone market in China, which is regarded as a blue ocean area. First, it is very important to accurately understand the Chinese consumers, who have a different consumption culture and value system from the Korean culture and system. This would help to identify priorities for the Chinese market. Further, considering the smartphone industry, where technological change is rapid, Korean companies will need to take prompt measures about market trends in order to establish strong competitiveness. Consequently, this study focused on analyzing the relationship between the variables of consumption value, satisfaction, and loyalty in the Chinese smartphone market. The principal dimensions of consumption value, which smartphones have, was analyzed, and the influence on satisfaction was identified. Moreover, the relationship among the variables of satisfaction, attitudinal loyalty, and behavioral loyalty was empirically analyzed. Research design, data, and methodology - This study examined the relationships between various consumption values (functional value, emotional value, social value, epistemic value, and economic value), along with satisfaction and loyalty. The data were collected through a questionnaire survey that was circulated to 310 customers who were users of smartphones in Chingdao and Yeontae regions in China. The survey was conducted from June 23 to August 4, 2013. A total of 301 responses to the questionnaires were collected and used for the data analysis. Moreover, a path analysis based on Lisrel 8.54 was used for the hypothesis test. Results - The variables of functional value, emotional value, social value, and epistemic value were revealed to have positive effects on satisfaction related to smartphone usage. However, the variables of monetary cost and psychological cost were not found to have negative effects on satisfaction related to smartphone usage. Moreover, satisfaction positively influenced attitudinal loyalty related to smartphone usage, but did not have a significant influence on behavioral loyalty related to smartphone usage. Specifically, satisfaction is essential, but not a sufficient condition for building behavioral loyalty in relation to smartphone usage. In addition, attitudinal loyalty positively influenced behavioral loyalty in relation to smartphone usage. Conclusions - First, this study shows that functional value, emotional value, social value, and epistemic value in relation to smartphone usage are important for marketing in the Chinese smartphone market. Particularly, functional value and emotional value play pre-eminent roles as regards customer loyalty in the use of smartphones. Second, the results of this study reveal that the variables of monetary cost and psychological cost are not important to the Chinese consumers. Specifically, the smartphone price and cognitive effort are not perceived as value barriers. Third, satisfaction did not guarantee behavioral loyalty in relation to smartphone usage, and the strategic approach for improving the repurchase and referral action in relation to smartphones based on solid attitudinal loyalty would be desirable and should be the focus of the marketing activities of Korean smartphone companies.

• Korean Journal of Family Social Work
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• no.57
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• pp.125-157
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• 2017

The purpose of this study was to analyse effects of public support for single-parent family for adolescent single-parent who experienced social exclusion and social network. This study utilized a part of National Youth Policy Institute's 'Research on the Actual Condition of the Adolescent Pregnancy, Birth and Rearing Children'. Participants of the study were 262 adolescent single-parents at the age of 24 and below. In order to understand the effect, this study verified the moderating effect of public support for single-parent family in the context of social exclusion and social network on parental attitude and behavior(parenting efficacy, parenting stress, negative parenting behavior). Results of this study are as follows; First, Nearly half of adolescent single-parent has economic hardship in original family and most they lived with preschool children on unemployed state that the average monthly income of them was about 600,000 won. It means that their financial independence difficult. Second, family support was only significant factor for parenting efficacy and positive relationship with family and acquaintances was major influence factor for causing positive parental behavior of adolescent single-parent. As a result, social network was verified more important factor than social exclusion on parental attitude and behavior. Lastly, public support for single-parent family was confirmed as social mitigation mechanism that has the moderating effect of social exclusion and social network on parental attitude and behavior.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.13 no.6
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• pp.63-74
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• 2018

Youth unemployment including college graduates has become more serious in recent years. It is very necessary to study the factors affecting entrepreneurship and entrepreneurial intentions. These days, the number of female entrepreneurs has been increased dramatically. There have been many successful entrepreneurs with technology background in Korea. Until now, there have been not so many empirical studies examining moderating effects of gender and college major. A lot of studies have examined the relationship between entrepreneurial orientation and entrepreneurial intention of college students. The purpose of this article is to examine gender and major as moderators in the relationship. Until now, there has been very few research investigating the moderating effects of gender and major on the relationship between entrepreneurial orientation and entrepreneurial intention. Survey questionaries were given to 400 college students randomly chosen in Gangwon-do. Finally, 334 surveys were used to analyze the relationship. The findings of our study are as follows. First, similar to previous studies, entrepreneurial orientation of college students has a positive effect on entrepreneurial intention. Second, participation both in school entrepreneurship courses and out of school entrepreneurship education does positively affect entrepreneurial intention. Gender and major are moderating variables between entrepreneurial orientation and entrepreneurial intention. Third, compared to male students, female students with low entrepreneurial orientation show much lower entrepreneurial intention. Fourth, compared to Non-STEM students, STEM students with low entrepreneurial orientation show much lower entrepreneurial intention. Thus, in order to improve entrepreneurial intention among college students, it is very important to develop entrepreneurial orientation, especially for female and STEM college students.