• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.132-132
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• 2013

Colloidal synthesis of nanoparticles with well-controlled size, shape, and composition, together with development of in situ surface science characterization tools, such as ambient pressure X-ray photoelectron spectroscopy (APXPS), has brought new opportunities to unravel the surface structure of working catalysts. Recent studies suggest that surface oxides on transition metal nanoparticles play an important role in determining the catalytic activity of CO oxidation. In this talk, I will outline the recent studies on the influence of surface oxides on Rh, Pt, Ru and Co nanoparticles on the catalytic activity of CO oxidation [1-3]. Transition metal nanoparticle model catalysts were synthesized in the presence of poly(vinyl pyrrolidone) polymer capping agent and deposited onto a flat Si support as two-dimensional arrays using the Langmuir-Blodgett deposition technique. APXPS studies exhibited the reversible formation of surface oxides during oxidizing, reducing, and CO oxidation reaction [4]. General trend is that the smaller nanoparticles exhibit the thicker surface oxides, while the bigger ones have the thin oxide layers. Combined with the nature of surface oxides, this trend leads to the different size dependences of catalytic activity. Such in situ observations of metal nanoparticles are useful in identifying the active state of the catalysts during use and, hence, may allow for rational catalyst designs for practical applications. I will also show that the surface oxide can be engineered by using the simple surface treatment such as UV-ozone techniques, which results in changing the catalytic activity [5]. The results suggest an intriguing way to tune catalytic activity via engineering of the nanoscale surface oxide.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.21-21
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• 2003

Male germ cell apoptosis has been extensively explored in rodent. In contrast, very little is known about their susceptibility to apoptosis stimuli of developing germ cell stages at the time when germ cell depletion after busulfan treatment occurs. Furthermore, it is still unanswered how spermatogonial stem cells are resistant to busulfan treatment. We examined the change of gene expression in detail using cDNA microarray analysis of mouse testis treated with busulfan. A subtoxic dose of busulfan (40mg/kg of body weight) transiently increased 228 mRNA levels among of the 8000 genes analyzed. TagMan analysis confirmed that the mRNA levels such as defensive protein, support protein, enzymatic protein, transport protein, and hormonal protein were rapidly increased. These results were re-confirmed by real-time PCR analysis. However, the expression levels of these genes induced by busulfan treatment were significantly reduced in control testis, indicating that both of male germ cells and somatic cells after busulfan treatment induces self-defense mechanism for protection of testicular cell death. Among them, we conclude that defense proteins play a key role in testis injury induced by busulfan.

• Journal of Dairy Science and Biotechnology
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• v.28 no.1
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• pp.17-28
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• 2010

A substantial body of evidence has emerged over the last decade in support of the novel concept that dietary calcium and dairy foods play an important role in regulating energy metabolism and thereby promote healthy weight management and reduce obesity risk. This concept has been demonstrated in experimental animals studies, cross-sectional and prospective population studies and a number of randomized clinical trials. Notably, the effects of dairy foods in weight management are more consistent than the effects of supplemental calcium across clinical trials, and calcium per se is responsible for approximately 40-50% of the effects of dairy. The calcium component is only effective in individuals with chronically low calcium intake, as it serves to prevent the endocrine response to low calcium diets which otherwise favors adipocyte energy storage; calcium also serves to promote energy loss via formation of calcium soaps in the gastrointestinal tract and thereby reduce fat absorption. The calcium-independent anti-obesity bioactivity of dairy resides primarily in whey. The key components identified to date are leucine and bioactive peptides resulting from whey protein digestion. The high concentration of leucine in whey stimulates a repartitioning of dietary energy from adipose tissue to skeletal muscle where it provides the energy required for leucine-stimulated protein synthesis, resulting in increased loss of adipose tissue and preservation of skeletal muscle mass during weight loss. Finally, dairy rich diets suppress the oxidative and inflammatory responses to obesity and thereby attenuate the diabetes and cardiovascular disease risk associated with obesity.

• Journal of the Korean Society for information Management
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• v.27 no.1
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• pp.229-248
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• 2010

Research has taken priority of many activities in universities and it has eventually brought the heat on research support services of libraries to meet high expectation of university researchers. To identify the major content areas and service methods of research guides serviced through digital libraries of universities, this study investigated research guides of 60 university libraries in North America and Korea. As a result, 13 categories for research guide contents were identified and 5 crucial areas for the contents development were suggested. It also analyzed providing methods of online research guides and communicating methods between librarians and users. Librarians were identified as the prime human resource to develope and manage research guides, which will play an important role in expanding diversity of librarians' roles in the future.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.69
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• pp.655-672
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• 2016

The main objective of this study is to examine the mediating effect of 'e-trust' on the relationship between the antecedents related to e-marketplace and the intention of using e-marketplace. Data was collected from a survey of 169 exporting firms in Gwangju, Korea. The results of the study are as follows ; First, 'e-trust' is produced a mediating effect when technology and government factors affect the intention of using e-marketplace. However, "e-trust" does not play a mediating role in the relationship between company factor and the intention of using e-marketplace. Second, technology factor, government factor and company factor have a positive impacts on the intention of using e-marketplace. Accordingly, in order to enhance the intention of using e-marketplace, small & medium exporting firms in Korea should try more to prepare for factors related to technology and company. In addition to these, government should give full support to be prepared for regulations and systems related to e-marketplace. If e-trust were properly built, the enhancement of using e-marketplace would be taken place more smoothly. So most of exporting firms can participate in e-marketplace more actively.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.299-320
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• 2005

To rapidly respond to uncertainties in the business environment whilst remaining competitive, every organization needs to be able to successfully introduce and manage organizational change. Cognizant of the role of information systems (IS) as an enabler of organizational change, many organizations have paid attention to Enterprise Resource Planning (ERP) systems for successful organizational change primarily because of their change-driving forces across organizations. In this study, we focus attention on the role of readiness for change in the ERP systems adoption. Readiness for change described as views about the need for organizational change is posited to be and antecedent of two expectancies about the need for organizational change is posited to be an antecedent of two expectancies about the system. performance expectancy and effort expectancy, which lead to actual system use. In order to further establish th relevance of readiness for change as a determinant of two expectancies, computer self-efficacy is considered to be other key predictor as well. In addition, this study proposes that the personal characteristics of organizational commitment and perceived personal competence play roles of important determinants of readiness for change. Based on data gathered from the users of the ERP systems, structural equation analysis using LISREL provides significant support for the proposed relationships. Theoretical and practical implications are discussed along with limitations.

• Journal of Microbiology and Biotechnology
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• v.25 no.11
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• pp.1871-1879
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• 2015

The complex roles of flagella in the pathogenesis of Campylobacter jejuni, a major cause of worldwide foodborne diarrheal disease, are important. Compared with the wild-type, an insertional mutation of the flgA gene (cj0769c) demonstrated significant decrease in the biofilm formation of C. jejuni NCTC11168 on major food contact surfaces, such as polystyrene, stainless steel, and borosilicate glass. The flgA mutant was completely devoid of flagella and non-motile whereas the wild-type displayed the full-length flagella and motility. In addition, the biofilm formation of the wild-type was inversely dependent on the viscosity of the media. These results support that flagellar-mediated motility plays a significant role in the biofilm formation of C. jejuni NCTC11168. Moreover, our adhesion assay suggests that it plays an important role during biofilm maturation after initial attachment. Furthermore, C. jejuni NCTC11168 wild-type formed biofilm with a net-like structure of extracellular fiber-like material, but such a structure was significantly reduced in the biofilm of the flgA mutant. It supports that the extracellular fiber-like material may play a significant role in the biofilm formation of C. jejuni. This study demonstrated that flgA is essential for flagellar biosynthesis and motility, and plays a significant role in the biofilm formation of C. jejuni NCTC11168.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.89-94
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• 2003

Rolling stock structures such as bogie frame and car body play an important role for the support of vehicle leading. In general, more than 25 years' durability is needed for them. A lot of study has been carried out for the prediction of the fatigue life of the bogie frame and car body in experimental and theoretical domains. One of the new methods is a probabilistic fatigue lift evaluation. The objective of this paper is to estimate the fatigue lift of the bogie frame of an electric car, which was developed by the Korea Railroad Research Institute (KRRI). We used two approaches. In the first approach probabilistic distribution of S-N curve and limit state function of the equivalent stress of the measured stress spectra are used. In the second approach, limit state function is also used. And load spectra measured by strain gauges are approximated by the two-parameter Weibull distribution. Other probabilistic variables are represented by log-normal and normal distributions. Finally, reliability index and structural integrity of the bogie frame are estimated.

• Journal of Computing Science and Engineering
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• v.6 no.3
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• pp.193-206
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• 2012

Keys play a fundamental role in all data models. They allow database systems to uniquely identify data items, and therefore, promote efficient data processing in many applications. Due to this, support is required to discover keys. These include keys that are semantically meaningful for the application domain, or are satisfied by a given database. We study the discovery of keys from SQL tables. We investigate the structural and computational properties of Armstrong tables for sets of SQL keys. Inspections of Armstrong tables enable data engineers to consolidate their understanding of semantically meaningful keys, and to communicate this understanding to other stake-holders. The stake-holders may want to make changes to the tables or provide entirely different tables to communicate their views to the data engineers. For such a purpose, we propose data mining algorithms that discover keys from a given SQL table. We combine the key mining algorithms with Armstrong table computations to generate informative Armstrong tables, that is, key-preserving semantic samples of existing SQL tables. Finally, we define formal measures to assess the distance between sets of SQL keys. The measures can be applied to validate the usefulness of Armstrong tables, and to automate the marking and feedback of non-multiple choice questions in database courses.

• Korean Journal of Human Ecology
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• v.23 no.6
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• pp.1127-1140
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• 2014

The purpose of this study was to explore the effects of father's socio-demographic variables and father's literacy beliefs on father's literacy interaction. Participants were 204 fathers who have children in 3 to 5 years of age. Data were analyzed by descriptive statistics, correlation analysis and stepwise multiple regression analysis. The findings are summarized as follows: (1) Father's education level was generally correlated with 'father role efficiency', 'open interaction', 'picture-book reading interaction' (2) Monthly income of the household was related 'father role efficiency', 'positive feelings on reading books'. (3) 'Literacy ability development from books', 'father role efficiency', 'positive feeling on reading books' were correlated 'open interaction' and 'picture book reading'. But, 'literacy ability development from books', 'father role efficiency', 'positive feeling on reading books' were negatively correlated 'direct interaction'. (4) The most influential factor on father's 'open interaction', 'direct interaction' was 'literacy ability development from books'. The most influential factor on father's 'picture-book reading' was 'positive feeling on reading books'. These findings highlight that 'literacy ability development from books' and 'positive feeling on reading books' may play critical roles in father's literacy interaction. So, it is very important that adequate training and support on father's literacy beliefs for father's high quality literacy interaction.