• Progress in Superconductivity and Cryogenics
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• v.10 no.2
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• pp.34-37
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• 2008

According to the recent design of an HTS (High Temperature Superconducting) power transformer whose capacity is hundreds MVA, the rated current values of the low voltage side are generally over thousands amps. Considering the performance of the recent HTS wires, it is inevitable to use several HTS wires in parallel for large rated current. Lots of stacked HTS wires were fabricated and tested so far, and the results have showed that we have to transpose each wire in order to reduce the AC losses as well as to increase the current capacity. But many development programs about HTS transformers reveal that the transposition of the several wires during the winding process is quite difficult not only in case of the layer windings but also in case of the pancake type ones. So, we need transposed multiple HTS wire which we can handle like single wire or cable for the HTS windings of large capacity power transformer. We fabricated several kinds of samples of multiple HTS wire with transposition to apply it to the HTS windings of power transformer. The electrical characteristics such as critical currents or AC losses are analyzed by experiments in case by case. Finally we present the best design of a multiple HTS wire for power transformer.

• Earthquakes and Structures
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• v.27 no.4
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• pp.303-315
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• 2024

This study proposes a comprehensive methodology for estimating accumulative damage of bridge structures under multiple seismic excitations, in the framework of site-specific probabilistic hazard analysis. Specifically, a typical earthquake-prone region in China is chosen to perform probabilistic seismic hazard analysis (PSHA) to find the mean annual rate (MAR) of ground motion intensity at a specific level, based on which, a mass of ground motion observations is selected to construct random earthquake sequences with various number of shocks. Then, nonlinear time history analysis is implemented on the finite element (FE) model of a RC girder bridge at the site of interest, to investigate structural responses under different earthquake sequences, and to develop predictive model for cumulative damage computation, in which, a scalar seismic intensity measure (IM) is adopted and its performance in damage prediction is discussed by an experimental column. Furthermore, a mathematic model is established to calculate occurrence probability of earthquakes with various number of shocks, based on PSHA and homogenous Poisson random process, and a modified cumulative damage indicator is proposed, accounting for probabilistic occurrence of various earthquake scenarios. At end, the applicability of the proposed methodology to main shock and aftershock scenarios is validated, and characteristics of damage accumulation under different multiple earthquake scenarios are discussed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.4
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• pp.268-278
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• 2017

The purpose of this research was to analyze the effect of psychological characteristics on job performances of workers at residential homes for the disabled. For the study, a survey was conducted on 170 workers at residential homes for the disabled in Gyeongsangbuk-do (Sangjoo-si, Andong-si and Yecheon-gun) from the 7th of October to 11th of November, 2016. For the analysis, SPSS WIN 18.0 and Amos 21.0 programs were used to conduct t-test, one-way analysis of variance, correlation analysis and multiple regression analysis at a significance level of 5%. The research results were as follows. First, it was found that the psychological characteristics of workers at residential homes for the disabled vary significantly upon their work loads. Second, the differences in job performances of workers at the residential homes for the disabled with their general characteristics were analyzed: it was revealed that the job performance of the workers varies significantly with their education levels, positions and monthly incomes. Third, the job performance of workers at the residential homes for the disabled was found to be having positive correlation with their psychological characteristics as follows: self-esteem (r=.363, p<.001) and self-efficacy (r=.275, p<.001), while having negative correlation with depression (r=-.267, p<.001). This paper is required to be used as a primary source for political development on the enhancement of the psychological characteristics of workers at residential homes for the disabled.

• Korea Journal of Hospital Management
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• v.19 no.4
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• pp.45-56
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• 2014

Purpose: This study aims to explore the effects of personal characteristics, satisfaction, quality of care, role performance, image, awareness level of public hospitals perceived by community residents on use-experience of public hospitals. Methods: A cross-sectional survey was conducted with 2,100 community residents around 39 district public hospitals. The questionnaire was designed to collected information on personal characteristics and community awareness of public hospitals. The community awareness consists of 5 factors and 15 items. The data were collected utilizing call-interview by a survey company. Results: The personal characteristic and community awareness were shown significant differences between having use-experience and not-having use-experience of public hospitals (p<.001), except gender. As the results of multiple logistic regression, the significant variables of use-experience of public hospitals were satisfaction (OR=1.06 95%CI=1.010-1.116), quality of care (OR=1.07, 95%CI=1.016-1.134, level of awareness to public hospitals (OR=1.50, 95%CI=1.378-1.632), age (OR=0.43, 95%CI=0.236-0.785), education (OR=1.62, 95%CI=1.013-2.590), type of medical security (OR=0.37, 95%CI=0.142-0.945). Conclusions: Public hospitals have to effort to improve community awareness through providing quality of care, and role performance. It is possible to support them by the Central and Local Government.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8C
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• pp.681-688
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• 2007

Applying an appropriate received signal processing algorithm based on the channel characteristics is important to improve the receiver performance. Wireless channels in general exhibit various time-delay characteristics depending on their power delay profile. When the estimated channel power summation is used to determine the amount of time delay, a channel adaptive receiver structure can be implemented. In this paper, we derive a closed-form expression for the error probability of the channel classification when the estimated channel power summation is used to classify channel groups having different time delay characteristics, and present the performance gain utilizing multiple estimation results.

• Anatomy and Cell Biology
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• v.56 no.4
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• pp.474-481
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• 2023

The dental characteristics created by acquired dental treatments can be used as age estimators. This pilot study aimed to analyze the correlation between the number of teeth observed for dental characteristics and chronological age and to develop new non-invasive age estimation models. Dental features on panoramic radiographs (420 radiographs of subjects aged 20-89 years) were classified and coded. The correlation between the number of teeth for each selected code (codes V, X, T, F, P, and L) and age was observed, and multiple regression was performed to analyze the relationship between them. Eleven regression models with various combinations of dental sextants were presented. The model with the data from both sides of the posterior teeth on both jaws showed the best performance (root mean square error of 14.78 years and an adjusted R² of 0.461). The model with all teeth was the second-best. Based on these results, we confirmed statistically significant correlations between certain dental features and chronological age. We also observed that some regression models performed sufficiently well to be used as adjunctive methods in forensic practice. These results provide valuable information for the design and performance of future full-scale studies.

• Journal of Venture Innovation
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• v.3 no.1
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• pp.143-163
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• 2020

When we assume the transition to a knowledge management society, what factors should be differentially added to the characteristics of CEOs of small enterprises to enhance management performance? This can be done by measuring the core competence of the CEO who is an importance asset of the small firms. This study focuses on the following four inquiries to clarify the relationship among the core competence of the CEO, the knowledge management and the performance of the firms. First, we test the influence of the core competence of CEO on business performance. Second, we explore the effects of CEO characteristics on the knowledge management and the performance of the firm. Third, we test whether knowledge management has a mediating effect in the relationship between the characteristics of CEO which is a parameter, and the business performance of the firm which is a dependent variable. Fourth, for the sake of a deeper understanding of the CEO of the small firms, we conduct t-test or multiple comparison to find out the statistically significant differences among means of the main variables such as demographic characteristics, work experience, and entrepreneurship. The academic contribution of this study is to verify the characteristics of the CEO, which influence the business performance:the global competence, challenge spirit, interpersonal flexibility and stress tolerance, in connection with the knowledge management of small firms. The practical contribution of this study is to test whether CEOs can demonstrate successful business performance through knowledge management rather than measuring business performance after a certain period of time through profit and loss statements in this era of uncertainty.

• Korean Management Science Review
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• v.31 no.2
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• pp.15-32
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• 2014

This research empirically investigated the influence factors on the adoption of environmental management systems (EMS) in Korean manufacturing firms. In this study, the external factors (cause factors), the internal factors (facilitating factors) and the firm specific characteristics were integrally considered. In the factor analysis, the third item (regional society) of the external factors and the first item (environmental law) of government regulation were confounded with the items of the other factors. Thus, the confounded items were removed. In the second factor analysis, no items were replicated. The results of a multiple regression analysis showed that the influence factors such as government regulation, normative pressure, top management support, environmental strategy and employees' recognition, and ratio of large shareholders have a significant impact on the construction of EMS. However, the effects of the other firm specific characteristics were not statistically significant. We also examined whether both the number of environmental personnel and the allocation of environmental resources, which are directly related with the adoption of EMS, have a moderating impact on the relationships between other internal factors and the construction of EMS. With a subgroup analysis, the moderating roles of the number of environmental personnel were empirically confirmed. Through a multiple regression analysis, the direct effects of the external factors on the adoption or construction of the internal factors were demonstrated. The effects of government regulation, normative pressure and imitative pressure on the internal factors were significant and positive. Finally, in this study, the fact that the adoption of EMS can improve the environmental performance of a firm was also empirically found.

• Journal of Convergence for Information Technology
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• v.8 no.2
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• pp.11-18
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• 2018

The purpose of this study was to analyze the effects of Socio-demographic Characteristics, perceived stress and depression of college students in Daegu and Kyungbuk provinces on problem drinking behavior. The subjects of the study were 295 college students who understood and agreed on the purpose of this study and conducted questionnaires using structured questionnaires. Data were analyzed with frequency, percentage, mean, standard deviation, t-test, ANOVA, Scheffe test, pearson correlation coefficient, and multiple regression analysis. The results showed that depression was the most influential factor in the problem drinking behavior of college students in Daegu and Kyungbuk provinces, followed by gender, academic performance, and residental type. Therefore, it is necessary to develop an intervention program that takes into account the social psychological approach to prevent depression of college students and the characteristics of gender, academic performance, and residental type in order to prevent problem drinking of college students.

• Asia-Pacific Journal of Business
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• v.15 no.1
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• pp.179-192
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• 2024

Purpose - The purpose of this study is to examine the effect of entrepreneurial experience, business model innovation and financing on new venture performance. Design/methodology/approach - This study analyzes survey data on new ventures in Korea and investigated research hypothesis by multiple regression analysis. Findings - Founders' prior startup experience have different impacts on performance depending on whether they had a successful or failed startup. Successful experience has a positive impact on early performance, while failure experience has a negative impact. Business model innovation shows a positive and significant relationship with early performance. External financing has different effects depending on the type of funding source and performance variables. VC funding is positively related to employment creation, while government R&D funding is negatively related to sales volume. Research implications or Originality - This study confirms that the impact of entrepreneurial experience on early performance varies depending on the characteristics of successful and unsuccessful entrepreneurs. It also empirically confirms that business model innovation has a significant impact on early performance. We empirically examine the relationship between various external financing sources of venture firms and early performance. Since the effects of entrepreneurial experience, business model innovation, and external financing on early stage performance may be different, entrepreneurs should consider these relationships when pursuing early stage business opportunities.