• Communications of Mathematical Education
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• v.20 no.2 s.26
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• pp.295-326
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• 2006

Despite the importance of mathematics education, many students in high school have lost their interests and felt difficulties and they don't have 'mathematical' experience with meanings attached because of the entrance examination. This paper attempted to resolve these problems and find the teaching-method with which students can study by themselves with more confidence. Nowadays students' use of Internet is very popular. After develop 'the development of mathematical power' program based on mathematics history, history, science, the application of problems in real world, and self-evaluation, I made students repeat them after making teaching lessons in classroom as moving pictures. Through this processes, I attempted to develop the Self-Directed Learning' ability by making public education substantial. First of all I analyzed the actual conditions on 'Self-Directed Learning' ability in mathematics subject, the conditions of seeing and hearing in Internet learning program, and students' and their parents' interests in Internet education. By analyzing the records, I observed the significance of the introducing mathematics history in mathematics subject in early stager, cooperative-learning, leveled-learning, self-directed learning, and Internet learning. Actually in aspect of applying 'the development of mathematical power' program, at first I made up the educational conditions to fix the program, collected the teaching materials, established the system of teaching-learning model, developed materials for the learning applying Internet mail and instruments of classroom, and carried out instruction to establish and practice mathematics learning plan. Then I applied the teaching-learning model of leveled cooperation and presentation loaming and at the same time constructed and used the leveled learning materials of complementary, average, and advanced process and instructed to watch teaching moving pictures through Internet mail and in the classroom. After that I observed how effective this program was through the interest arid attitude toward mathematics subject, learning accomplishment, and the change of self-directed learning. Finally, I wrote the conclusion and suggestion on the preparation of conditions fur the students' voluntary participation in mathematics learning and the project and application on 'the development of mathematical power' program and repeated learning with the materials of moving pictures in classroom.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.402-408
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• 2010

In the twenty first century, people experience a lot of stresses by psychological, social and environmental impetus. If the stress is excessive, it can become a problem and finally lead to diseases. Foot bath makes the body warm starting with the feet, controls the blood circulations and autonomic nervous systems. This study aims at examining the effects of stress and fatigue of senior students preparing for college entrance examination by foot bath with the aroma essential oil and the fermentation extracts. The experimental period was from March 30 to April 18, 2009. The study objects were 21 senior students of C Girls' High School in Cheonan. They were divided into 3 groups and treated 20 times. The first group was a foot bath group with Artemisia Herbal fermentation extracts. The second group was a foot bath group with the blending aroma essential oil of grapefruit, cypress and cedarwood. The third group was not treated. In the case of difference of physical and psychological stress, there was a reduction of 18.43 and 16.71 for the fermented extract group and 10.71 and 9.43 for the aroma group, while a reduction of 0.43 and 0.29 for the control group, respectively. This shows that foot baths using fermented extracts and aroma had lower physical stress compared to the control group (p<.01). For the difference of fatigue, there was a reduction of 19.14 for the fermented extract group, 11.57 for the aroma group and 0.07 for the control group, showing that foot baths accompanied by fermented extracts and aroma used in this study having lower fatigue compared to the control group (p<.01). The fermented extract group (M=55.71) had the highest level of satisfaction after foot baths, followed by the aroma group (M=49.14) and the control group (M=33.29). Duncan's post hoc test showed that there was a statistically considerable difference between the tests groups and control groups (p<.01). Through the results of this study, it was found that foot baths using bathing supplements were very effective for reducing stress and fatigue.

• Progress in Medical Physics
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• v.22 no.4
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• pp.163-171
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• 2011

The purpose of this study was to investigate the effect of various technical parameters for the dose optimization in pediatric chest radiological examinations by evaluating effective dose and effective detective quantum efficiency (eDQE) including the scatter radiation from the object, the blur caused by the focal spot, geometric magnification and detector characteristics. For the tube voltages ranging from 40 to 90 kVp in 10 kVp increments at the FDD of 100, 110, 120, 150, 180 cm, the eDQE was evaluated at the same effective dose. The results showed that the eDQE was largest at 60 kVp when compares the eDQE at different tube voltage. Especially, the eDQE was considerably higher without the use of an anti-scatter grid on equivalent effective dose. This indicates that the reducing the scatter radiation did not compensate for the loss of absorbed effective photons in the grid. When the grid is not used the eDQE increased with increasing FDD because of the greater effective modulation transfer function (eMTF). However, most of major hospitals in Korea employed a short FDD of 100 cm with an anti-scatter grid for the chest radiological examination of a 15 month old infant. As a result, the entrance surface air kerma (ESAK) values for the hospitals of this survey exceeded the Korean DRL (diagnostic reference level) of $100{\mu}Gy$. Therefore, appropriate technical parameters should be established to perform pediatric chest examinations on children of different ages. The results of this study may serve as a baseline to establish detailed reference level of pediatric dose for different ages.

• Journal of Preventive Medicine and Public Health
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• v.5 no.1
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• pp.97-104
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• 1972

For the purpose of ascertaining the status of physical growth and health status of the University Students, an intensive survey was conducted by the authors towards a total of 1,250 (Male 792, Female 458) who passed the written entrance examination at the Kyung Hee University in 1972. The items included the measurements on physical growth, various physical and nutritional indices, status of visual distourbance, dental status and tuberculosis. The findings and results cad be summarized as follows; 1. Physical Growth and Develspment. i) The average of body height by anthropometric was $169.39{\pm}5.05cm$ in male and $157.45{\pm}4.43cm$ in female. ii) The averages of body weight by sex were $59.42{\pm}6.47Kg\;and\;51.81{\pm}5.21Kg$, respectively. iii) The averages of chest-girth were $87.18{\pm}5.30cm\;and\;80.51{\pm}4.53cm$. iv) The averages of sitting-height were $92.21{\pm}2.79cm\;and\;86.28{\pm}2.57cm$. In all cases the male measurements were higher than female. 2. Various ludices about Physical Growth and Development; i) Relative body weights by sex were 35.08 and 32.91, relative chestgirth 51.47 and 51.13, and relative sitting-height 54.43, 54.79, respectively. ii) Rohrer index was 1.222 in males and 1.327 in females, Kaup index 2.071 and 2.089, Verveck index 86.54 and 84.04, and Pelidisi index 91.15 and 93.08, respectively 3. Status of visual distourbance The vision of the students under 0.8 with Landolt's testing chart was 45.4% in left eye and 46.6% in right eye(male: 44.4% and 45.7%, female: 47.2% and 48.0%), while under 0.6 in both visions was 41.0% and 40.5% (male: 40.8% and 40.7%, female: 41.5% and 40.2%), respectively. 4. Dental Status Out of total 19.4% (male 19.2%, female 19.6%) had gingivitis, the female incidence rate of gingivitis was higher than male. Average number of teeth in each subject was 29.6 teeth: male had 29.9 teeth and female had 29.1 teeth. The caries rate was 78.9%(male 75.6%, female 84.5%), the female caries rate was higher than male. Total filing per subject was 35.6% (male 34.0%, female 37.1%), female incidence was higher shan male. The average number of i) Caries per tooth rate was 8.5% in male and 9.2% in female, ii) Missing per tooth rate was 0.3% and 0.2%, iii) Filling per tooth rate was 3.9% and 4.2%. in all cases, the female incidences were higher than the male. The average number of D.M.F. was 3.8 teeth in male and 4.0 teeth in female, female was higher than male. The average rate of D.M.F. was 12.7% in male and 13.7% in female, female was higher than male. 5. Pulmonary infiltration Among the total, 53 students were diagnosed as pulmonary infiltration (tuberculosis), of whom 51 were minimal cases, one were moderately advanced case and one were far advanced case.

• Journal of Preventive Medicine and Public Health
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• v.1 no.1
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• pp.67-78
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• 1968

For the purpose of ascertaining the status of physical growth and health status of the University students, a intensive survey was conducted by the authors towards a total of 2,638(male; 2,228, female; 410) who passed the written entrance examination at the Seoul National University. The items included the measurements on physical growth, various physical indixes, visual acuity, tuberculosis and dental status. The findings and results can be summarized as follows: 1. Physical Growth No significant difference was found in the physical growth between classes(literature and science) and by ages. In males, the means of body height, body weight, chest-girth and sittingheight were $168.0{\pm}5.07cm,\;55.7{\pm}5.71kg,\;85.8{\pm}4.4cm\;and\;91.5{\pm}2.21cm$, respectively. In females, these were $157.4{\pm}4.57\;cm,\;00.4{\pm}5.75kg,\;80.3{\pm}4.51cm\;and\;86.1{\pm}3.30cm$, respectively. Basing on the above measurements several physical indixes were calculated as follows ; Relative body weight 33.15 in males and 32.02 in females. Relative chest-girth 51.07 and 51.01, relative sitting-height 54.46 and 54.70 $R\ddot{o}hrer$ index 1.00 and 1.02, Kaup index 1.97 and 2.04, Vervaeck index 83.63 and 83.03, and Pelidisi index 89.94 and 92.45. 2. Visual Acuity Among the students of science classes those of 0.8 and below in vision on left and right occupied 46.4% and 45.0%, those of 0.6 and below 39.1% and 41.2%, respectively. Among the students of literature classes those of 0.8 and below occupied 46.3% and 42.9%, and those of 0.6 and below occupied 41.4% and 39.0, respectively. In males those of 0.8 and below occupied 46.8% and 44.5% and 0.6 and below occupied 41.9% and 39.7%, while in females 0.8 and below occupied 43.9%, and 42.4%, and 0.6 and below occupied 38.3% and 37.3%, respectively. In males those of 0.8 and below in corrected vision occupied 12.1% and 10.3%, while in females 12.9% and 12.2%, respectively. More students of abnormal vision were found among science classes and the proportions of corrected vision were 38.9% and 37.4% in males, and 33.9% and 33.2% in females, respectively. 3. Tuberculosis Among the total, 55 students were diagnosed as tuberculosis, of whom 50 were minimal cases, 2 were moderately advanced cases and 3 were far advanced cases. 4. Dental Status Among the total, 81.2% were of decayed teeth, 20.8% filled, 9.5% missed, 5.0% extraction needed, 9.1% sunplatinum bridges, 3.3% golden bridges and 5.5% golden inlay. Regarding tartar on teeth moderate, heavy and light grades occupied 49.5%, 29.7% and 20.3%, respectively and 0.8% had none. 5. Comprehensive evaluation According to criteria 4 grades were applied to comprehensive evaluation as follows : A...excellent in physical status B...with some physical defects but no difficulties in study C...need treatment D...need treatiment and rest Out of the total, A grade occupied 21.6%, B 76.2% and C. and D 2.2.

• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.897-904
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• 2022

The purpose of this study is to compare the difference in dose and image quality when applying the diagnostic reference level (DRL) test conditions for head radiography in a digital radiation environment and the test conditions currently applied in clinical practice. I would like to review the conditions of radiographic examination. In this study, the head model phantom was targeted, and the investigation conditions were divided into clinical conditions (Clinic), DRL value (DRL₇₅), and DRL average value (DRL_mean). For dose, Enterance surface dose (ESD) was measured, and for image quality, signal-to-noise ratio and contrast-to-noise ratio were measured and analyzed for comparison. The average values of skull anterior posterior(AP) ESD according to the changes in test conditions were Clinic 1214.03±4.21 µGy, DRL₇₅ 3017.83±8.14 µGy, DRL_mean 2283.50±7.09 µGy, and skull lateral (Lat). The average value of ESD was statistically significant with Clinic 762.79±3.54 µGy, DRL₇₅ 2168.57±10.83 µGy, and DRL_mean 1654.43±6.48 µGy (p<0.01). The average values of SNR and CNR measured in the orbital, maxillary sinus, frontal sinus, and sella turcica were statistically significant (p<0.01). As a result of this study, compared to DRL, the conditions used in clinical practice showed lower dose levels of about 58% for AP and about 70% for Lat., and there was no qualitative difference in terms of image quality. Through this study, it is necessary to consider a new diagnostic reference level suitable for the digital radiation environment, and it is considered that the dose should be reduced accordingly.

• The korean journal of orthodontics
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• v.25 no.4
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• pp.497-509
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• 1995

With socioeconomic development and change of esthetic recognition, the demand for orthodontic treatment and number of orthodontic patients has been increasing so rapidly. And frequency of malocclusion was changed. So this study was done in an attempt to provide an epidemiologic study so that we can accomodate their orthodontic needs adequately and to obtain the reliable quantitative information regarding the characteristics of orthodontic patients who visited Department of Orthodontics, Seoul National University Hospital from 1985 to 1994. Following results were obtained. 1. The total number of orthodontic patients of SNUDH during 1990-1994 increased in comparing with that of 1985-1989. And it showed that the number of annual patients was increasing trend. 2. The total number of female patients was 1.59 times as high as that of male. It showed that the annual percentage of female patients has been increasing and that of male patients has been decreasing. So demands for orthodontic treatment of malocclusion of female patients were higher than that of male patients. 3. Each total percentage of class I, class II div.1, class II div. 2 and class III was 35.98%, 14.00%, 1.74% and 48.28%. The annual percentage of class I group had been decreasing but it has increased at 1994. However that of Class III group had been increasing until 1991 but it has been decreasing. 4. Each percentage of less than 6 year-old group, D to 8 year-old group, 8 to 12 year-old group, 12 to 18 year-old group and more than 18 year-old group was 2.65%, 8.63%, 32.50%, 27.74% and 28.48%. Annual percentage of 12 to 18 year-old group ( middle & high school students group ) had been decreasing but it has been increasing. However 18 year-old group had been increasing but it has been decreasing. So entrance examination for college and university is an important factor to distribution of age group.