• Journal of Power Electronics
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• v.16 no.3
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• pp.840-848
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• 2016

A primary-side regulation AC-DC converter operating in the PFM (Pulse Frequency Modulation) mode with a high precision output current is designed, which applies a novel inductance compensation technique to improve the precision of the output current, which reduces the bad impact of the large tolerance of the transformer primary side inductance in the same batch. In this paper, the output current is regulated by the OSC charging current, which is controlled by a CC (constant current) controller. Meanwhile, for different primary inductors, the inductance compensation module adjusts the OSC charging current finely to improve the accuracy of the output current. The operation principle and design of the CC controller and the inductance compensation module are analyzed and illustrated herein. The control chip is implemented based on a TSMC 0.35μm 5V/40V BCD process, and a 12V/1.1A prototype has been built to verify the proposed control method. The deviation of the output current is within ±3% and the variation of the output current is less than 1% when the inductances of the primary windings vary by 10%.

• Journal of the Korean Society of Radiology
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• v.83 no.2
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• pp.387-393
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• 2022

Primary pulmonary malignant melanoma is an extremely rare type of melanoma. The radiologic features of primary pulmonary malignant melanoma are nonspecific; however, it almost always presents as a well-demarcated round or lobulated solitary solid nodule or mass. Herein, we report the case of a 78-year-old male with primary pulmonary malignant melanoma that was mistaken for primary pulmonary adenocarcinoma with lepidic growth and was seen as bilateral multiple subsolid nodules on CT.

• Research in Mathematical Education
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• v.9 no.4 s.24
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• pp.317-328
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• 2005

The aim of this study is to investigate future teachers' skills that can make problem solving methods concrete for 7-11 year old students. For the students in the concrete operations level, solutions of word problems should also be taught by concreting. But most of teacher candidates can not solve the problems without algebra because they got used to solve the word problems with algebra during their high school and university education. In this study, whether the teacher candidates have the skills of solving the primary school level problems without using algebra or not are being observed. At the end of this observation it is determinated that primary level teacher candidates generally prefer using algebra operations because of their former habits. The results show that in the education of the primary level teacher candidates, there is the need of developing the solving skills using figures and diagrams without algebra rather than algebraic solutions in word problems.

• Journal of the Korean Institute of Educational Facilities
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• v.19 no.3
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• pp.21-31
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• 2012

According to the decrease in birth rate and reduction of population in rural area, primary schools have brought about many problems for decrease of number of student, and environment of education have became deteriorated. Accordingly, primary schools be required improvement, and it should be altered placement of schools because it change number of student, distance and time of attending school, and formation of school zone are changed by alternating of human and physical environment. Merger and abolition of primary school is inevitable for change of placement standard to primary school and qualitative improvement of environment of education in rural area. This study suggests the effective space planning methods for unified school and appropriate utilization alternatives for closed school following after the merger and abolition of small rural schools. In doing so, it explores the present models of merger and abolition through analysis of all sort of actual condition and the possibilities for various utilizations of the abolished schools. It proposes a classroom-operation type fused the comprehensive class and departmental class system for merged primary schools in rural area. It also suggests the re-use methods of closed school facilities for students and community. Finally, it emphasizes that in order to success the policy of the merger and abolition of small schools, it be attributed to the social-cultural environment based on local residents and community and required provision of a variety of utilization plans reflecting local specifics and guarantee of local residents' participation and selection.

• Journal of the Korean Institute of Educational Facilities
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• v.19 no.2
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• pp.21-31
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• 2012

This study is with the subjects of 7 primary schools in Daejon City which opened after 2004 when the Ministry of Education & Human Resources Development released the "Study of Developing the Manual for Safety and Plan of school facilities". This is to study the measures of improving or enhancing the safety criteria on the school facilities from the viewpoint of actual planning as well as of architectural planning through investigating and analysing the cause, the status and the type of negligent accidents by school which are occurring both directly and indirectly. Though the analysis of the examined contents shows there is no facility in primary schools not satisfying 'the criteria on safety maintenance of school facilities', the criteria is so comprehensive and general that its content is just itemized and the current criteria of facilities are not fit for the present situation because of the physical condition of the students in elementary, middle and high schools and the changing curriculum.

• Journal of the Korean Society of School Health
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• v.14 no.2
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• pp.187-206
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• 2001

The study was carried out to estimate the prevalence and possible causes of refractive errors in primary school children. At one primary school in urban Daegu, one in the medium-sized city of Yongcheon and 2 in rural areas, children wearing glasses and children with visual acuity of less than 0.7 were given our questions. 354 out of 378 children responded to our questions. The research was done from March 2000 to February 2001. The data were analyzed by percentage, x2 test, t-test, ANOVA and Scheff method. Children with eyesight problems were more prevalent in urban areas than rural areas. The lack of luminosity during reading (p=0.015), length of reading time (p=0.08) and posture which watching TV (p=0.023) appeared leading causes of progressing myopias. The visual impairment caused by refractive errors may affect the mental and physical activity of primary school children and lead to social isolation, loneliness and depression. However, little attention may be paid by professionals engaged in providing health care to the children. Once we have recognized the impact of visual impairment, we may be in a better position to prevent progressing refractive errors.

• The Korean Journal of Cytopathology
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• v.6 no.2
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• pp.116-124
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• 1995

Eighty cases of malignant effusion were cytologically studied to elucidate the incidence of primary tumor site and cytologic characteristics of each tumor types. Eighty fluid specimens were composed of 43 ascitic, 35 pleural, and 2 pericardial effusion and primary tumor site had been confirmed by histology. The frequent primary sites were stomach(22 cases, 28%), lung(21 cases, 26%), ovary(11 cases, 14%), liver(7 cases, 9%), and breast (4 cases, 5%). The principal malignant tumors were adenocarcinoma (56 cases, 70%), squamous cell carcinoma (7 cases, 9%), liver cell carcinoma (7 cases, 9%), small cell carcinoma (4 cases, 5%), and non-Hodgkin's lymphoma (4 cases, 5%). The distinctive cytologic findings according to primary tumor types were as follows; the gastric adenocarcinomas were mainly characterized by isolated cells and irregular clusters sometimes with signet ring cells. Papillary serous cystadenocarcinoma of ovary showed frequently papillary clusters and occasional psammoma bodies. Breast carcinoma of ductal type showed cell balls with smooth margins. Colonic adenocarcinoma showed rather irregular clusters or palisading pattern of cylindrical cells. Metastatic squamous cell carcinoma, liver cell carcinoma, small cell carcinoma, and non-Hodgkln's lymphoma showed also characteristic features. These findings Indicate that the cytological features observed in the great majority of malignant effusion are similar to those of primary tumor types, which are very helpful to indentify the primary tumor site.

• Child Health Nursing Research
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• v.13 no.4
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• pp.486-494
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• 2007

Purpose: This study was executed to investigate the route of the sexual knowledge acquisition and the sexual problem behavior of primary school students in a region. Method: The subjects of this research who were primary school 5, 6 grade students of 990 people were chosen at random in big cities, small towns and rural areas in Jeonbuk province. Result: The route of the sexual knowledge acquisition was through taking lesson & teacher in the school(40.6%), the peer group or senior member(26.1%), internet(15.3%), parents(10.0%), and multimedia(8.0%). The domain of the sexual problem behavior showed sexual impulse 3.8%, sexual violence 3.7%, masturbation 2.7%, voyeur 1.8%, prostitution 0.8%, transvestism 0.5%, exhibitionism 0.1%. The sexual problem behavior experienced by 5.0% or more of the subjects showed the experience of another person's compulsory touching on their body, the embrace desire and the kiss desire with opposite sexual friend. And the biggest sexual problem behavior of the subjects was sexual violence and sexual impulse to opposite sexual friend. The experience rate of the 6 grade was higher than that of the 5 grade (p<.05) and the male students' experience rate of another person's compulsory touching on their body showed higher than that of the female students(p<.05). Conclusion: The author through these findings suggests that systematic programs and curriculum should be developed for sexual problem behavior prevention.

• Journal of The Korean Association of Information Education
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• v.2 no.2
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• pp.239-244
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• 1998

The ONCHO system described in this paper is the Primary School Education System Based-on Web Database in order to offer the diverse primary school education services. The main purpose of ONCHO system is to share eduacational learing data of primary school eduacation, to exchange letters, and to evaluate learning contents.

• The Journal of the Korean dental association
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• v.16 no.5 s.108
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• pp.391-394
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• 1978

The authors had surveyed on the snack foods of 300 primary school children in Seoul in order to obtain the informations for the dietary counseling and suggestions as a method of dental caries prevention. The obtained results were as follows; 1. Primary school children had the intake of the snack foods in the order of the apple, the candy, the orange, the cake, the milk, the biscuit, the Ramyeontang, the regular gum, the persimon, the Tugpokie. 2. Of the primary school children, 5.6% had intaking no snack food, but 10.6% once, 21.6% twice, 29.0% three times, and 33.0% four times or over in a day, respectively.