• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.600-608
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• 2016

This paper proposes a new high-efficient interleaved phase-shift full-bridge (PSFB) converter for low-voltage and high-current power systems. The proposed converter is composed of three switch-bridges and two transformers in the primary side and two rectifiers in the secondary side. Each transformer handles half of the total power with an interleaved operation, so that the proposed converter has high system reliability, as much as the conventional interleaved PSFB converter. The soft-switching characteristics of the proposed converter are better than those of the conventional converter due to the modulated primary side configuration. The proposed converter represents a single lagging-leg bridge, which has a poor soft switching condition in its operation, while the conventional converter has two lagging-leg bridges in its operation. Therefore, the number of switches having hard-switching conditions is reduced by half in the proposed converter. In addition, the reduced switch counts in the primary side of the proposed converter helps decrease the complexity of the proposed converter compared to that of the conventional converter. The operational principle and analysis are presented in this paper and the characteristics are verified using a PSIM simulation with 3kW server power specification.

• Journal of Information Science Theory and Practice
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• v.6 no.1
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• pp.31-44
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• 2018

Purpose: This study aims to examine the research output in the field of nursing at the global level during the last two decades, viz., for the period 1996-2015, with special reference to India. Some of the aspects examined include the research growth in nursing literature during the period of study, leading nursing research countries at the regional and global level, and citation analysis. Scope and Methodology: This study is global in nature, but emphasis has also been laid on India's research contribution in nursing at the global level. Aspects like regional contribution to the nursing research output have also been assessed. This study is purely based on secondary data retrieved from SCImago Journal and Country Rankings. The figures in the study are based on one particular database and are not exhaustive; hence they simply reflect a trend in nursing research at the global level. Findings: During the period 1996 through 2015, a total of 550,490 research articles were published across the world by 212 nation states at an average of 2,596 articles from each individual country. On average, during the period of study, the number of nursing research publications grew at the rate of 7.36% each year. North America has emerged as one of the leading nursing research continents of the world by publishing 218,614 research articles, constituting 39.71% of the global nursing research output. The U.S. and U.K. are the world's two leading nursing research countries, which contributed 193,819 and 61,730 research articles respectively, comprising a 35.21% and 11.21% share of global nursing research output. India and China, apart from being the two fastest growing nursing research countries, have the potential to meet the global human resource demand in the field of nursing, given the skilled and trained human resource both these countries possess in nursing. Social Implication: There is always a need to share working knowledge in some professions and nursing is one of them. There cannot be a better medium than linking practice with theory through the research medium. Metric studies in turn help to get a better idea about the amount of work done in any given field at the national and international level, thus identifying the need thereof to improve upon those areas where there is research lag.

• Journal of Yeungnam Medical Science
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• v.7 no.1
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• pp.69-80
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• 1990

A clinical analysis was done on 23 patients(24 hips) with fracture of the femoral neck, who had been admitted and treated at our Orthopedic department during the period of 4 years, from Jan, 1984 to May 1988. The results were as follows : 1. 23 patients were comprised of 4 males and 19 females, and 11 patients were over 65 years old. 2. 18 cases of 24 cases were due to minor traumas such as slipping down, and for over 65 years old, all cases were due to simple minor traumas, 8 cases were showed a severe osteoporosis, below grade 3 of the Singh's index. 3. 14 cases of 24 cases were displaced subcapital fractures, and 6 cases displaced transcervical fractures. Only 4 cases were the undisplaced transcervical fractures. 4. In treatment of fractures internal fixations after manipulation were performed in 14 cases and primary arthroplasties in 10 cases. Secondary arthroplasties were done in complicated 4 cases of 14 cases treated with internal fixations. 5. Complications after internal fixation were developed in 7 cases out of 14 cases, avascular necrosis in 6, nonunions in 2, pin migrations in 3, and metal failure in 1 case. 6. In 14 arthroplasty immediate surgical fitness of femoral stem were related to late loosening of femoral stem(correlation coefficient r=-0.68, p<0.01).

• Kidney Research and Clinical Practice
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• v.37 no.4
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• pp.356-365
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• 2018

Background: Woman kidney donors face obstetric complication risks after kidney donation, such as gestational hypertension and preeclampsia. Studies on childbirth-related complications among Asian women donors are scarce. Methods: This retrospective cohort study included woman donors aged 45 years or younger at the time of kidney donation in a single tertiary hospital between 1985 and 2014. Pregnancy associated complications were investigated using medical records and telephone questionnaires for 426 pregnancies among 225 donors. Matched non-donor controls were selected by propensity score and the maternal and fetal outcomes were compared with those of donors. Primary outcomes were differences in maternal complications, and secondary outcomes were fetal outcomes in pregnancies of the donor and control groups. Results: A total of 56 cases had post-donation pregnancies. The post-donation pregnancies group was younger at the time of donation and older at the time of delivery than the pre-donation pregnancies group, and there were no differences in primary outcomes between the groups except the proportion receiving cesarean section. Comparison of the complication risk between post-donation pregnancies and non-donor matched controls showed no significant differences in gestational hypertension, preeclampsia, or composite outcomes after propensity score matching including age at delivery, era at pregnancy, systolic blood pressure, body weight, and estimated glomerular filtration ratio (odds ratio, 0.63; 95% confidence interval, 0.19-2.14; P = 0.724). Conclusion: This study revealed that maternal and fetal outcomes between woman kidney donors and non-donor matched controls were comparable. Studies with general population pregnancy controls are warranted to compare pregnancy outcomes for donors.

• Journal of health informatics and statistics
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• v.43 no.4
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• pp.245-254
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• 2018

Objectives: This paper examines how serious the appearance concerns of adolescents is in South Korean society by delving into the formation and changes of adolescents' appearance concerns. Methods: We conducted a secondary analysis of the data of multi-year tracing surveys which the National Youth Policy Institute opened to the public. The repeated Measures ANOVA, the paired t-test, and a chi-squared test were applied against the data. Results: It was found that about one out of ten adolescents experienced concerns that began as early as the upper grades of elementary school, reached its peak in middle school, and decreased afterwards. On the other hand, some of them faced enduring appearance concerns and seemed to suffer from it. One interesting finding is that adolescents once relieved from the concerns were free from it permanently. We also found that there were considerable differences between male and female adolescents in terms of the level of concerns they experienced, their peak periods, and other characteristics. Conclusions: Appearance concerns changes dynamically according to development of adolescence. Appearance concerns was less prevalent among adolescents than predicted, and it seemed considerably fluid. Our study not only confirms but also challenges some important findings of previous studies.

• Korean Journal of Comparative Education
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• v.26 no.4
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• pp.1-30
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• 2016

The purposes of this study are to analyze the higher education admission policy of France and to draw policy implications for Korea. For this study, literature reviews and interviews (face-to-face, email, telephone) were adopted for main research methods. The major findings were as follows: First, baccalaur?at diploma is necessary for higher education admission in France but each higher education has different admission policy according to their legal status. University has open enrollment policy and has no student selection process. Other higher institutions such as grands ?coles select students based on students' academic achievements. Second, baccalaur?at is national diploma which shows successful conclusion of the upper secondary education and gives right of access to higher education. This diploma is awarded to candidates who have passed a series of standardized written and oral tests drawn up at national level (10/20points). Third, students' academic achievements in high schools are major criteria for admission for higher institutions which has student selection process. Fourth, entrance exams implemented at college level are various according to higher institution. Last, 'Admission Post-bac-APB' site is used to support and facilitate the whole admission process. Based on these findings, several policy implications were suggested.

• Clinical and Experimental Reproductive Medicine
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• v.32 no.3
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• pp.207-216
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• 2005

Objective: To understand the crucial requirement for the normal early folliculogenesis, we evaluated molecular as well as physiological differences during in vitro ovarian culture. Among the important regulators for follicle development, anti-Müllerian hormone (AMH) and FSH Receptor (FSHR) have been known to be expressed in the cuboidal granulosa cells. Meanwhile, it is known that c-kit is germ cell-specific and GDF-9 is also oocyte-specific regulator. To evaluate the functional requirement for the competence of normal follicular development, we investigated the differential mRNA expression of several factors secreted from granulosa cells and oocytes between in vivo and in vitro developed ovaries. Materials and Methods: Ovaries from ICR neonates (the day of birth) were cultured for 4 days (for primordial to primary transition) or 8 days (for secondary follicle formation) in ${\alpha}$-MEM glutamax supplemented with 3 mg/ml BSA without serum or growth factors. The mRNA levels of the several factors were investigated by quantitative real-time PCR analysis. Freshly isolated 0-, 4-, and 8-day-old ovaries were used as control. Results: The mRNA of AMH and FSHR as granulosa cell factors was highly increased according to the ovarian development in both of 4- and 8-day-old control. However, the mRNA expression was not induced in both of 4- and 8-day in vitro cultured ovaries. The mRNA expression of GDF-9 known to regulate follicle growth as an oocyte factor was different between in vivo and in vitro developed ovaries. In addition, the transcript of GDF-9 was expressed in the primordial follicles of mouse ovaries. The mRNA expression of c-kit was not significantly different during the early folliculogenesis in vitro. Conclusion: This is the first report regarding endogenous AMH and FSHR expression during the early folliculogenesis in vitro. In conclusion, it will be very valuable to evaluate cuboidal granulosa cell factors as functional marker(s) for normal early folliculogenesis in vitro.

• Journal of The Korean Society of Clinical Toxicology
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• v.12 no.2
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• pp.63-69
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• 2014

Purpose: The aim of this study is to investigate the difference between male and female in some clinically meaningful aspects and to prevent intentional poisoning in children and adolescents. Methods: Retrograde medical records review of patients who visited the emergency department of two secondary hospitals for drug ingestion from March 2010 through March 2013 was performed. Unintentional ingestion or ingestion by others was excluded. Results: A total of 138 cases were reported, male 25.4% (n=35), female 74.6% (n=103). The reason for poisoning was intentional in 132 cases (95.7%) and misuse in six cases (4.3%). In female patients, non-prescription drugs was the most common cause of intentional poisoning (68.9%). Male patients tend to use life substances for intentional poisoning more frequently (20.0%) than female (3.9%). Seven male patients and 12 female patients had previous psychiatric history and 34.3% of male and 41.7% of female were consulted to the psychiatric department. Conclusion: Female adolescents are more likely to ingest drugs intentionally for suicide attempt than males of comparable ages. The drugs they ingested were, in many cases, obtained with ease from the drug store nearby and, remarkably, most of the drugs they obtained in that way were acetaminophen-containing. This suggests that some guidelines or control in the pharmacy that restrict children or adolescents from obtaining potentially or possibly life-threatening drugs might be necessary. In addition, education regarding drugs is thought to be necessary in school for teenagers as they tend to misuse them with incorrect acknowledgement.

• Journal of the Korean Society for Library and Information Science
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• v.53 no.4
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• pp.5-22
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• 2019

The purpose of this study is to analyze the factors that hinder the role recognition and role performance of teacher librarians and suggest some improvement methods. For this purpose, a questionnaire was conducted among 41 persons who participated in the first-level qualification training for teachers librarians at K University Secondary Teacher Training Institute in 2019.The results showed that there was a difference between the expected role and the execution role of the teacher librarians. In other words, teacher librarians recognize that they should teach information literacy as instructors and operate library-based instruction and cooperative classes as teaching partners. However, the most frequently played roles are reading education and library use education. They recognizes the cause as institutional limitations, such as the absence of a national level curriculum and the ambiguity of the role of specialists in school libraries. And it is perceived as a real problem such as the lack of partnership and recognition of their peers. Among the variables of teacher librarians, the higher their educational level, the more they perceived their peers as teachers. Based on this, some suggestions for strengthening the role of the teacher librarians' instructor and teaching partner were proposed in terms of including cross-curricular subjects of information literacy education, analyzing jobs and establishing scholarship system for school libraries.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.516-523
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• 2021

A study using selective catalytic reduction (SCR) was conducted in conjunction with ammonia as a reducing agent for controlling nitrogen oxides, a typical secondary inducer of fine dust in the atmosphere. For NH₃-SCR experiments, a commercial catalyst of V/W/TiO₂ only and also V/W-Sb/TiO₂ catalyst with Sb were used, and phosphorous durability was confirmed. As a result of NH₃-SCR experiments, it was confirmed that the addition of Sb to V/W/TiO₂ had durability against phosphorous. In addition, the physical and chemical properties were comparatively analyzed through BET, XPS, H₂-TPR, NH₃-TPD, and FT-IR analysis. From the anaylsis results, when Sb was added to V/W/TiO₂ catalyst, P was also added resulting in the formation of SbPO₄ and the generation of VOPO₄ was suppressed. The phosphorous durability was confirmed by maintaining the redox characteristics of the catalyst before P was added.