• The Journal of Society for e-Business Studies
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• v.17 no.4
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• pp.69-93
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• 2012

Various influence-related relationships in Social Network Services (SNS) among users, posts, and user-and-post, can be expressed using links. The current research evaluates the influence of specific users or posts by analyzing the link structure of relevant social network graphs to identify influential users. We applied the concept of mutual interactions proposed for ranking semantic web resources, rather than the voting notion of Page Rank or HITS, to blogosphere, one of the early SNS. Through many experiments with network models, where the performance and validity of each alternative approach can be analyzed, we showed the applicability and strengths of our approach. The weight tuning processes for the links of these network models enabled us to control the experiment errors form the link weight differences and compare the implementation easiness of alternatives. An additional example of how to enter the content scores of commercial or spam posts into the graph-based method is suggested on a small network model as well. This research, as a starting point of the study on identifying influential users in SNS, is distinctive from the previous researches in the following points. First, various influence-related properties that are deemed important but are disregarded, such as scraping, commenting, subscribing to RSS feeds, and trusting friends, can be considered simultaneously. Second, the framework reflects the general phenomenon where objects interacting with more influential objects increase their influence. Third, regarding the extent to which a bloggers causes other bloggers to act after him or her as the most important factor of influence, we treated sequential referencing relationships with a viewpoint from that of PageRank or HITS (Hypertext Induced Topic Selection).

• Tuberculosis and Respiratory Diseases
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• v.65 no.3
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• pp.191-197
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• 2008

Background: Due to the irreversible nature of chronic obstructive pulmonary disease (COPD), the treatment aim in patients with COPD is not to cure but to reduce the symptoms, increase lung function, and improve the quality of life. It has been suggested that depression is a common emotional disturbance in patients with COPD who are faced with a major physical impairment and embarrassing symptoms. This study evaluated the prevalence and risk factors of depression in patients with chronic obstructive pulmonary disease. Methods: A total of 59 patients with a registered diagnosis of chronic obstructive pulmonary disease were selected. Depression was assessed using the Centers for Epidemiologic Studies Depression (CES-D) scale. The quality of life was assessed using the Korean version of the St. George's Respiratory Questionnaire. Results: The prevalence of depression was 17.0%. In the correlation model, the interaction of the $FEV_1%$ over predicted value and SGRQ score(symptom, activity, impact, overall score) was statistically significant. The interaction of the $FEV_1%$ over predicted value and depression scale(CES-D) was also statistically significant. There was a positive correlation between the SGRQ scores(symptom, activity, impact, overall score) and the depression scale. Conclusion: The prevalence of depression in patients with chronic obstructive pulmonary disease is relatively high. The pulmonary function and the living standards were found to be significant risk factors for depression.

• Asian Oncology Nursing
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• v.3 no.2
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• pp.133-144
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• 2003

This study is carrying out a before and after experiment design for the non-equal comparative group to identify the effects of the breast self-examination education on breast self-examination participant education compliance and health promotion in women. The subject of this study was 58 women residing in Chungju. Their age ranged from 20 to 40. These women were not pregnant or did not breast feed, as well as they did not have any breast disease, at the time of survey. They were available for the response to the questionnaires, and understood the purpose of this study. They also agreed to participate in the study, and responded to the 3rd time questionnaires to the end. Thus, brochures and lectures were provided side by side to a group of 19 of those women, and only brochures were provided to another group of 39 of those women. With regard to education, a brochure and a program using a breast model were applied. Then, the frequency of the breast self examination compliance, breast self examination capability and the relations between the breast self examination and activities to promote health were measured, before the education, after 4 weeks of education and after 12 weeks of education. Before education and after 4 weeks of education. I collected the questionnaires myself visiting them, and after 12 weeks of education, the questionnaires were collected by mail. In relation to the study tool, the breast self examination activity was measured by two measuring tools: breast self examination activity frequency and breast self examination compliance capability. As for the frequency, the number of self examination for the period of 3 months, before the questionnaire survey, was measured in the form of self report. In relation to the tool to measure the breast self examination capability, the BSEPRI tool, which was developed by Wood in 1994, was used. Here, as the score was higher, the capability was indicated to be higher. The translated and revised version of Health Promoting Lifestyle Profile II (Walker, Sechrist & Pender. 2002) was used as a tool for health promotion. As the measured score was higher, the health promoting activity was indicated to be higher. The results of this study were as follows: 1. As a result of checking the breast self examination compliance frequency between the experiment group that received the breast self examination participant education and the comparative group that did not receive the education, there was a significant difference in interaction between groups by time, as time passed by. 2. As a result of checking the breast self examination compliance capability between the experiment group and the comparative group, there was a significant difference in interaction between groups by time, as time passed by. 3. As a result of carrying out a repetitive measurement analysis, between the experiment group that received the breast self examination education and the comparative group that did not receive the education, which was carried out to validate the hypothesis that the former would have higher health promoting activities than the latter, there was no significant difference after the breast self examination education was conducted.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.2
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• pp.47-65
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• 2020

With the era of the Fourth Industrial Revolution in sight, innovative business models utilizing new technologies are emerging, and startups are enjoying an abundance of opportunities based on the agility to respond to disruptive innovations and the opening to new technologies. However, what is most important in creating a sustainable start-up ecosystem is not the start-up itself, but the process of research-start-investment-investment-the leap to listing and big business-in order to build a virtuous circle of startups that leads to re-investment. To this end, the environment created in the hub area where start-ups were conducted is important, and these material and non-material environmental factors are described as being inclusive by the word "entrepreneurial ecosystem." This study aims to provide implications for Korea's entrepreneurial ecosystem through the study of the interaction of the elements that make up the start-up ecosystem and the relationship of ecosystem participants in Singapore. Singapore has been consistently mentioned as the top two Asian countries in assessing the start-up environment and business environment. In this process, six elements of the entrepreneurial ecosystem presented by Isenberg(2010)-policies, finance, culture, support, human resources, and market-are the best frameworks for analyzing entrepreneurial ecosystems in terms of well encompassing prior studies related to entrepreneurial ecosystem elements, and a model of regional transformation is formed focusing on some elements to suit Singapore, the target area of study. By considering that Singapore's political nature would inevitably have a huge impact on finance, Smart Nation policy was having an impact on university education related to entrepreneurship, and that the entrepreneurial networks and global connectivity formed within Singapore's start-up infrastructure had a significant impact on Singapore's start-up's performance, researches needed to look more at the factors of policy, culture and market. In addition, qualitative research of participants in the entrepreneurial ecosystem was essential to understand the internal interaction of the elements of the start-up ecosystem, so the semi-structured survey was conducted by visiting the site. As such, this study examined the status of the local entrepreneurial ecosystem based on qualitative research focused on policies, culture and market elements of Singapore's start-up ecosystem, and intended to provide implications for regulations related to start-ups, the role of universities and start-up infrastructure through comparison with Korea. This could contribute not only to the future research of the start-up ecosystem, but also to the creation of a start-up infrastructure, boosting the start-up ecosystem, and the establishment of the orientation of the start-up education in universities.

• Journal of the Korean Society of Groundwater Environment
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• v.5 no.4
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• pp.177-191
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• 1998

For various kinds of waters including surface water, shallow groundwater (＜70 m deep) and deep groundwater (500∼810 m deep) from the Pungki area, an integrated study based on hydrochemical, multivariate statistical, thermodynamic, environmental isotopic (tritium, oxygen-hydrogen, carbon and sulfur), and mass-balance approaches was attempted to elucidate the hydrogeochemical and hydrologic characteristics of the groundwater system in the gneiss area. Shallow groundwaters are typified as the 'Ca-HCO$_3$'type with higher concentrations of Ca, Mg, SO$_4$and NO$_3$, whereas deep groundwaters are the 'Na-HCO$_3$'type with elevated concentrations of Na, Ba, Li, H$_2$S, F and Cl and are supersaturated with respect to calcite. The waters in the area are largely classified into two groups: 1) surface waters and most of shallow groundwaters, and 2) deep groundwaters and one sample of shallow groundwater. Seasonal compositional variations are recognized for the former. Multivariate statistical analysis indicates that three factors may explain about 86% of the compositional variations observed in deep groundwaters. These are: 1) plagioclase dissolution and calcite precipitation, 2) sulfate reduction, and 3) acid hydrolysis of hydroxyl-bearing minerals(mainly mica). By combining with results of thermodynamic calculation, four appropriate models of water/ rock interaction, each showing the dissolution of plagioclase, kaolinite and micas and the precipitation of calcite, illite, laumontite, chlorite and smectite, are proposed by mass balance modelling in order to explain the water quality of deep groundwaters. Oxygen-hydrogen isotope data indicate that deep groundwaters were originated from a local meteoric water recharged from distant, topograpically high mountainous region and underwent larger degrees of water/rock interaction during the regional deep circulation, whereas the shallow groundwaters were recharged from nearby, topograpically low region. Tritium data show that the recharge time was the pre-thermonuclear age for deep groundwaters (＜0.2 TU) but the post-thermonuclear age for shallow groundwaters (5.66∼7.79 TU). The $\delta$$\^$34/S values of dissolved sulfate indicate that high amounts of dissolved H$_2$S (up to 3.9 mg/1), a characteristic of deep groundwaters in this area, might be derived from the reduction of sulfate. The $\delta$$\^$13/C values of dissolved carbonates are controlled by not only the dissolution of carbonate minerals by dissolved soil CO$_2$(for shallow groundwaters) but also the reprecipitation of calcite (for deep groundwaters). An integrated model of the origin, flow and chemical evolution for the groundwaters in this area is proposed in this study.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.411-416
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• 1996

Supercritical fluid extraction of ${\beta}$-carotene from carrot was optimized to maximize ${\beta}$-carotene (Y) extraction yield. A central composite design involving extraction pressure ($X_1$ 200-,100 bar), temperature ($X_2,\;35-51^{\circ}C$) and time ($X_1$$ 60-200min) was used. Three independent factors ($X_1,\;X_2,\;X_3$) were chosen to determine their effects on the various responses and the function was expressed in terms of a quadratic polynomial equation,$Y={\beta}_0+{\beta}_1X_1+{\beta}_2X_2+{\beta}_3X_3+{\beta}_11X_12+{\beta}_22X_3^2+{\beta}_-12X_1X_2+{\beta}_12X_1X_2+{\beta}_13X_1X_3+{\beta}_23X_2X_3,$ which measures the linear, quadratic and interaction effects. Extraction yields of ${\beta}$-carotene were affected by pressure, time and temperature in the decreasing order, and linear effect of tenter point (${\beta}_11$) and pressure (${\beta}_1$) were significant at a level of 0.001(${\alpha}$). Based on the analysis of variance, the model fitted for ${\beta}_11$-carotene (Y) was significant at 5% confidence level and the coefficient of determination was 0.938. According to the response surface of ${\beta}$-carotene by cannoical analysis, the stationary point for quantitatively dependent variable (Y) was found to be the maximum point for extraction yield. Response area for ${\beta}$-carotene (Y) in terms of interesting region was estimated over $10,611{\mu}g$ Per 100 g raw carrot under extraction.

• Journal of The Korean Association For Science Education
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• v.30 no.6
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• pp.693-718
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• 2010

This study investigated secondary school science teachers' experiences to explore the influencing factors in science teachers efficiency (STE). The participants, thirty three secondary school science teachers who have more than four years of teaching experience, were interviewed about describing each teacher's experience throughout one's years of teaching. The grounded theory introduced by Strauss and Corbin (1998) was used to analyze the data in this study. The results of paradigm analysis revealed that STE is influenced by 125 concepts, 38 sub-categories, and 16 categories. In a paradigm model, the central phenomenon was 'constructing STE', and the causal condition was 'want to be a teacher' as career choice motivation. The contextual conditions that have an affect on the central phenomenon were 'self awareness of the teacher' and 'social awareness of the teacher.' The mediate conditions, which facilitated or restrained the action/interaction strategies, were 'societal tendency', 'school climate', and 'personal context.' The action/interaction strategies to control the phenomenon were 'following the line,' 'identifying effective teaching strategies,' 'taking teacher education programs,' and 'contributing to school improvement.' The consequences were 'teacher's self awareness', 'challenge,' and 'stagnating in teaching.' The overall conclusion drawn from this research is that, the definition of STE is beliefs in science teachers' capabilities to set up objects in some school teaching context and, organize and execute the course of action required to attain these. Additionally, STE has three dimensions of teacher's behaviors: science instructional efficiency, efficiency in engaging students, and efficiency in managing school conditions. This study offers insight into the nature of STE and theoretical framework. These findings may give science teachers and teacher educators the practical knowledge necessary to build effective training programs and interventions that would help increase STE and facilitate effective teaching.

• The Korean Journal of Financial Management
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• v.21 no.2
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• pp.99-123
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• 2004

We focus in this study on incremental financing decisions and estimate a logit model for the probability a firm will choose a private placement over a public bond issue. We hypothesize that information asymmetry, financial risk, agent cost, and proprietary information may affect a firm's choice between public debt and private placements. We find that as the size of firm increases, the probability of choosing a private placement declines significantly. The age of the firm, however, is not a significant factor affecting the firm's choice between public and privately-placed bond. The coefficients on the firm's leverage and non-investment grade dummy are significantly positive, meaning firms with high financial risk and credit risk select private placements. The findings regarding agency-related variables, PER and Tobin's Q, are somewhat complex. We find significant evidence that firms with high PER prefer private placements to public bonds, suggesting that borrowers with options to engage in asset substitution or underinvestment are more likely to choose private placements. The coefficient of Tobin's Q is negative, but not significant, which weakly support the hold-up hypothesis. When we construct an interaction term on the Tobin's Q with a non-investment rating dummy, however, the Tobin's Q interaction term becomes positive and significant. Thus, high Tobin's Q firms with a speculative rating are significantly more likely to choose a private placement, regardless of the potential hold-up problems. The ratio of R&D to sales, proxy for proprietary information, is positively significant. This result can be interpreted as evidence in favor of a role for proprietary information in the debt sourcing decision process for these firms.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.650-658
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• 2006

The recycling of TDA from solid waste of TDI plant(TDI-R) by near-critical hydrolysis reaction had been studied by means of a statistical design of experiment. The main and interaction effects of process variables had been defined from the experiments in a batch reactor and the correlation equation with process variables for TDA yield had been obtained from the experiments in a continuous pilot plant. It was confirmed that the effects of reaction temperature, catalyst type and concentration, and the weight ratio of water to TDI-R(WR) on TDA yield were significant. TDA yield decreased with increases in reaction temperature and catalyst concentration, and increased with an increase in WR. As a catalyst, NaOH was more effective than $Na_2CO_3$ for TDA yield. The interaction effects between catalyst concentration and temperature, WR and temperature, catalyst type and reaction time on TDA yield had been defined as significant. Although the effect of catalyst concentration on TDA yield at $300^{\circ}C$ as subcritical water was insignificant, the TDA yield decreased with increasing catalyst concentration at $400^{\circ}C$ as supercritical water. On the other hand, the yield increased with an increase in WR at $300^{\circ}C$ but showed negligible effect with WR at $400^{\circ}C$. The optimization of process variables for TDA yield has been explored with a pilot plant for scale-up. The catalyst concentration and WR were selected as process variables with respect to economic feasibility and efficiency. The effects of process variables on TDA yield had been explored by means of central composite design. The TDA yield increased with an increase in catalyst concentration. It showed maximum value at below 2.5 of WR and then decreased with an increase in WR. However, the ratio at which the TDA yield showed a maximum value increased with increasing catalyst concentration. The correlation equation of a quadratic model with catalyst concentration and WR had been obtained by the regression analysis of experimental results in a pilot plant.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.5
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• pp.93-104
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• 2019

The entrepreneurship can be a source of national growth potential as behavioral tendencies of people who seek innovation, take risks of failure, and proactively respond to opportunities. In particular, in the economic situation of Korea where growth has been stagnated, it is necessary to strengthen the entrepreneurship of women which is relatively lower than men's in order to activate the start-up and economic participation of the whole people. In this regard, this study focuses not only on gender differences in entrepreneurship but also on the hidden impact of social contexts that cause gender differences in entrepreneurship. Specifically, this study examined the moderating effects of childbirth, a factor that reflects the social context of Korea in the relationship between gender and entrepreneurship. According to the results of the model that includes the interaction effect of these variables in addition to the independent effects of gender and childbirth, the gender effect disappeared, while the significant effect of both the childbirth variable and the interaction variable of gender and childbirth were confirmed. Furthermore, according to additional analysis, which identified the differences in entrepreneurship by creating four types of treatment groups based on gender and childbirth status, entrepreneurship was significantly lower in the 'female and childbirth' group than in all other groups. The difference between the remaining treatment groups was not statistically significant. These results indicate that differences in entrepreneurship levels between men and women overlap not with the unique trait of men and women, but with the social contextual effects of Korea, where women are under the full burden of childbirth and parenting. This study suggests implications that effective policy measures to promote women's entrepreneurship or economic activity should be taken by taking into account the social context of Korea that suppresses women's entrepreneurial behavior.