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31.
The general problem of root-clustering and root-distribution of a polynomial in a certain region Γ in the complex plane has been investigated in this paper. The region Γ is general and includes all the previously investigated regions. For the root-clustering problem, it is shown that by using a certain transformation, the necessary and sufficient condition can be represented either in terms of positive definite (p.d.) or positive innerwise (p.i.) matrices. The entries in these matrices are rational functions of the coefficients of the polynomial. The connection between p.d. and p.i. matrices is established in terms of matrix multiplication. 相似文献
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PurposeThis study analyzed the process of changes in Korean Library and Information Science curriculum and evaluated the courses currently available by using a perception survey of librarians in the field. It also explored a possible demand for new courses, while suggesting compulsory, core, and optional courses for Bachelor's degree curriculum in Library and Information Science worldwide including Korea and the US.Design/Methodology/ApproachThis study progressed through a total of 5 steps as follows: investigating the background of why current courses of Library and Information Science were offered (interview), finding out the current courses in Library and Information Science (homepage search and phone interview), finding out which courses students have actually completed among those available (literature and resource research), evaluating the practicality of the available courses by librarians in the field (survey), and exploring the demand for new courses (survey). In addition, this study analyzed the process of change in the courses offered by investigating the curriculum over the last 20 years.FindingsFirst and foremost, it was found that the decision of which course will be offered is strongly influenced by faculty. Second, in the analysis of the process of opening up new courses, it was revealed that the number of courses is growing and the courses are becoming more diversified and more specific. Third, the survey results of the completion of curriculum for the last three years in 10 universities demonstrate that only 50% of the available courses are being completed. Fourth, in the survey of which courses the librarians in the field think are necessary among the 90 courses suggested, 21 courses scored more than 4 points in a 5-point Likert scale regarding the demand for new courses. Fifth, the new courses which scored high levels of demand points were: Practice in Organizing and Managing Web Resources, Library Planning, Marketing, and Assessment, Understanding Information Technology for Managing Digital Collections, and Information and Communication in a Digital Age. Sixth, this study shows that there is a high level of agreement between courses completed by students and those which gained high levels of demand points in the practicality evaluation.Limitations/ImplicationsAs this study was performed in Korea where the Bachelor's degree course is fundamental, it will contribute valuable information to countries where universities have recently opened or are trying to open programs for Bachelor's degrees in Library and Information Science such as the US, or to curriculum study in countries such as China and Japan which have educational environments similar to Korea. However, similar studies need to be performed in different countries.Originality/ValueThis study has great significance as it has analyzed not only the curriculum of the last 20 years but also discovered how many of the newly created courses have actually been completed by students and the opinions of librarians in the field on these courses; there has not been such an encompassing study as this either inside or outside of Korea. 相似文献
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June Ahn 《The Information Society》2013,29(2):99-109
Many studies have examined the relationship between social network sites (SNSs) and the development of social capital. However, most studies to date have only considered college and adult populations. This study examines the patterns of SNS use in an urban, teenage sample in the United States. It tests the hypothesis that use of SNSs is related to higher levels of social capital. The results show that youth who use Facebook and Myspace report higher social capital in both their school and online relationships. In addition, the analysis suggests that distinct modes of SNS experiences are differentially related to bridging and bonding social capital. Time spent in SNSs is related to bridging capital, while positive or negative experiences are related to bonding capital. The study offers new insights into how youth experience SNSs and the relationship of that experience with their connection to the world. 相似文献
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This study examined how past information-seeking experience influences individuals’ information-seeking decision process following an event that increases uncertainty in close relationships. To examine this issue, a two-wave, cross-lagged, panel-design study was conducted, and outcome expectancy, communication efficacy, and information-seeking were measured at each time. Analyses revealed that communication efficacy mediates the link between outcome expectancies and information-seeking under the conditions of uncertainty. The results also suggest that communication efficacy and information-seeking impact each other cyclically. The findings of this research suggest that scholars should focus on people's information-seeking experience and communication efficacy when examining information-seeking following events that increase uncertainty in close relationships. 相似文献
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Jill L. Jacobi-Vessels E. Todd Brown Victoria J. Molfese Ahn Do 《Early Childhood Education Journal》2016,44(1):1-9
Attention to early childhood mathematics instructional strategies has sharpened due to the relatively poor mathematics performance of U.S. students in comparison to students from other countries and research evidence that early mathematics skills impact later achievement. Early Childhood counting skills form the foundation for subsequent mathematics learning. In this article, we discuss the milestones of counting development and examine preschool classroom mathematics observations through the lenses of two CLASS Dimensions, Concept Development and Instructional Learning Formats. Recommendations for effective instructional strategies around counting and suggestions for incorporating mathematics instruction into storybook reading are provided. 相似文献
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This study presents a new approach to synthesizing differential item functioning (DIF) effect size: First, using correlation matrices from each study, we perform a multigroup confirmatory factor analysis (MGCFA) that examines measurement invariance of a test item between two subgroups (i.e., focal and reference groups). Then we synthesize, across the studies, the differences in the estimated factor loadings between the two subgroups, resulting in a meta-analytic summary of the MGCFA effect sizes (MGCFA-ES). The performance of this new approach was examined using a Monte Carlo simulation, where we created 108 conditions by four factors: (1) three levels of item difficulty, (2) four magnitudes of DIF, (3) three levels of sample size, and (4) three types of correlation matrix (tetrachoric, adjusted Pearson, and Pearson). Results indicate that when MGCFA is fitted to tetrachoric correlation matrices, the meta-analytic summary of the MGCFA-ES performed best in terms of bias and mean square error values, 95% confidence interval coverages, empirical standard errors, Type I error rates, and statistical power; and reasonably well with adjusted Pearson correlation matrices. In addition, when tetrachoric correlation matrices are used, a meta-analytic summary of the MGCFA-ES performed well, particularly, under the condition that a high difficulty item with a large DIF was administered to a large sample size. Our result offers an option for synthesizing the magnitude of DIF on a flagged item across studies in practice. 相似文献
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Taekwondo's cultural identity is considered in the light of the controversy over its historical origins. After reviewing several existing theories, the meaning and development of taekwondo as a Korean martial art is explored. There are two conclusions: first, taekwondo is a fusion of several different sources; second, taekwondo is essentially a martial art that focuses on foot skills, and this distinguishes it from Japan's karate and China's wushu, which are primarily based on hand skills. The fact that all terms are rendered into pure Korean words shows the essence of Korean localization. Thus taekwondo incorporates a distinct identity as a Korean martial art. 相似文献
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Applying the framework of Construal Level Theory (CLT), this study tested the effects of an environmental ad describing the distant-future (i.e. end of the twenty-first century) vs. near-future (i.e. next summer) consequences of climate change using a sample of college students in the U.S. and South Korea. Consistent with the proposed empirical model in this study, lower perceived temporal distance of climate change generally led to higher perceived relevance of the event and more positive attitude and greater intention toward the sustainable consumption suggested in the ad (i.e. using Energy Star® qualified bulbs). However, the effects of temporal framing on the variables were moderated by the culture-specific ways in which the participants represented time and interpreted temporal information. In response to the distant-future frame, South Korean participants tended to report significantly shorter perceived temporal distance, thus presenting higher levels perceived relevance, stronger pro-environmental attitudes, and stronger behavioral intention than their U.S. counterparts. Overall, the findings of this study have meaningful implications for the external validity of CLT and for the development of effective climate change awareness campaigns targeting different audiences around the world. 相似文献
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Reginald Tran Byungwook Ahn David R. Myers Yongzhi Qiu Yumiko Sakurai Robert Moot Emma Mihevc H. Trent Spencer Christopher Doering Wilbur A. Lam 《Biomicrofluidics》2014,8(4)
Cell culture in microfluidic systems has primarily been conducted in devices comprised of polydimethylsiloxane (PDMS) or other elastomers. As polystyrene (PS) is the most characterized and commonly used substrate material for cell culture, microfluidic cell culture would ideally be conducted in PS-based microsystems that also enable tight control of perfusion and hydrodynamic conditions, which are especially important for culture of vascular cell types. Here, we report a simple method to prototype perfusable PS microfluidics for endothelial cell culture under flow that can be fabricated using standard lithography and wet laboratory equipment to enable stable perfusion at shear stresses up to 300 dyn/cm2 and pumping pressures up to 26 kPa for at least 100 h. This technique can also be extended to fabricate perfusable hybrid PS-PDMS microfluidics of which one application is for increased efficiency of viral transduction in non-adherent suspension cells by leveraging the high surface area to volume ratio of microfluidics and adhesion molecules that are optimized for PS substrates. These biologically compatible microfluidic devices can be made more accessible to biological-based laboratories through the outsourcing of lithography to various available microfluidic foundries. 相似文献
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