• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.6
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• pp.496-504
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• 2011

Introduction: This study compared the alveolar bone density of the mandible according to gender, age and position using Cone-beam computed tomography (CT). Materials and Methods: The maxillofacial CT scan data was obtained from 60 Korean patients. In addition, the alveloar bone density of 5 males and 5 females with normal occlusion aged from 10 to 70 years was measured at the buccal cortical bone, cancellous bone and lingual cortical bone, as well as at the position of the incisors, canines, premolars and molars. Results: The age-specific mean bone density was highest in patients in their third decade. The buccal cortical bone of the molars showed the highest bone density. Males in their fifties and sixties had a higher bone density in the cancellous bone in the region of the premolars and the buccal cortical bone of the molars, respectively, than females but there was no significant difference between males and females in the other parts. The cancellous bone density was highest in those in their twenties and thirties, and tended to decline up to their seventh decade. Conclusion: These results revealed a significantly different bone density according to gender, age and position in the Korean population. In addition, it is possible to predict the bone density based on these results.

• Korean Journal of Digital Imaging in Medicine
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• v.3 no.1
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• pp.126-132
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• 1997

Purpose : To apply to Program of Auto processor quality control after comparison of Film density variations with amendments to Auto density by using Check density program and Adjust density program of calibration mode into the Laser imager. Methods : Observe Check and Adjust density variations on the Control chart with standard step and value during seven months from December, 1995 to June, 1956 extending twice a week. (1) Measure density value on the steps after printing out 17-step sensitometric pattern of the Check density program. (2) In the same way, measure density values after amending density by using Adjust density program If they are exceeding allowable error limit. Results : In case of Check density program, the exceeding limit rates of Density difference(DD) and Middle density(MD) are: FL-IM3543 DD=75%. MD=72.5%, FL-IMD DD=0%. MD=30.8%(14.5%) After amending density by using Adjust density program, the exceeding limit rates of all both Laser imager were zero percent. The standard deviations are show lower FL-IM D than FL-IM3543 on the Check density control chart, but higher on the Adjust density control chart. Conclusion : (1) Check density variations by printingout sensitometric pattern extending once a week at least for quality control of the Laser imager. (2) In case of a dusty place, check the Laser beam transmission after cleaning Laser optical unit extending once a month. (3) Be sure to measure and check density values by using adjust density program if they are exceeding allowable error limit. (4) Maintain much better film density by performing the adjust density program even if check density values are existed within normal limit.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2003.07a
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• pp.76-76
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• 2003

This study was conducted to investigate dietary and other factors affecting bone mineral density (BMD) in Korean premenopausal women. Seventy-eight premenopausal women who visited health promotion center for health examinations volunteered to participate in this study and they were divided into two groups according to the bone status by T-score : normal or osteopenic group and osteoporotic group. The demographic and general characteristics, and dietary intake were surveyed using the questionnaire. BMDs of the lumbar spine and femoral neck of subjects were measured by dual energy X-ray absorptiometry. Serum samples were measured for Lipid concentration, and calcium, phosphorus, alkaline phosphatase as bone formation indicators. Urine was analysed for creatinine as bone resolution indicators. The results are as follows:The mean BMDs of the lumbar spine and femoral neck were 1.21 0.02g/cm$^2$ and 0.97 0.04g/cm$^2$, respectively and the BMD levels of osteoporotic group were significantly lower than that of normal or osteopenic group (p<0.001, respectively). Height in osteoporotic group was significantly lower than that of normal or osteopenic group (p<0.01), and bodyweight did not show any significant difference but had a lower tendency. Mean daily intake of energy was 1720 52ka1. When nutrient intake was compared with recommended dietary allowances (RDA) of subjects, calcium, Fe, vitamin A and riboflavin intakes showed means lower than RDA. The nutrient intake did not show any significant difference between normal or osteopenic group and osteoporotic group except intakes of protein fat and niacin. Serum and urine levels did not show any significant differences between normal or osteopenic group and osteoporotic group and all were within normal range, however, serum alkaline phosphatase level of osteoporotic group was significantly higher than that of normal or osteopenic group (p<0.001). Height showed positive correlations with lumbar spine bone mineral density (LBMD, r=0.332, p<0.01), no correlation was found with femoral neck bone mineral density (NBMD). Age, age at menarche, bodyweight, body mass index (BMI) and obesity showed no correlation with BMD. The BMD of the lumbar spine was significantly and positively related to the intake of niacin and vitamin C (r=0.236, p<0.05; r=0.274, p<0.05). Serum levels of calcium and phosphorus showed a negative correlation with LBMD (r=-0.698, p=0.0001; r=-0.503, p=0.0001, respectively). The results suggested that the BMDs of the lumbar spine was positively related to the intake of niacin and vitamin C in premenopausal women. Therefore, this study confirmed that one of the most effective way to minimize bone loss would be higher intake of niacin and vitamin C rich foods and habitual physical activity may have a beneficial effect on BMD in premenopausal period.

• Journal of Korean Physical Therapy Science
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• v.8 no.2
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• pp.1015-1021
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• 2001

Objectives: The objective of this study was to investigate analysis of women with low back pain and osteoporosis were measured for 40 normal in the women from July 20, 2000 to October 20, 2000. Methods: Bone mineral density(BMD) of lumbar spine was measured using energy absorptiometry and were correlated with age, calcium. alkaline phosphatase. bone mineral density standard T scores(p<0.05). Results: The bone mineral density of the lumbar spine decreased with aging, The bone mineral density of the lumbar spine decreased with the serum calcium and phosphate increased. The mean bone mineral density of the lumbar spine of healthy women in age($50\sim59$) was $0.83g/cm^2$, the lumbar spine of women low back pain in age($50\sim59$) was 0.75 glad. Conclusion: In the multiple regression of risk factors to bone mineral density(BMD) of lumbar spine were correlated with age, of abortion, calcium, bone mineral density standard T scores(p<0,05). In the prevention and early diagnosis and treatment of osteoporosis, the physician should consider the risk factors.

• Research in Community and Public Health Nursing
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• v.24 no.2
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• pp.236-244
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• 2013

Purpose: This study was to investigate lifestyles and identify factors influencing the bone mineral density (BMD) among employees in a community. Methods: Data were collected from 199 employees. Their lifestyles and BMIs were measured with a self-report questionnaire. As for their BMDs, their calcanei were measured with Quantitative Ultrasound. Results: Assessing their BMDs with reference to the WHO standards, 52.8% of the subjects' calcaneus BMDs were normal and 44.2% showed osteopenis, 3.0% showed osteoporosis. Age (odds ratio=1.05, p=.029), exercise (odds ratio=.31, p=.006) and the number of eating meals per day (odds ratio=1.97, p=.046) were significant factors influencing the subjects' BMDs. Conclusion: Strategies to emphasize exercise and dietary habits in employees are important for improving their bone mineral density. Programs for improving bone mineral density based on life cycle need to be developed.

• Transactions on Electrical and Electronic Materials
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• v.12 no.5
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• pp.204-208
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• 2011

In this paper, the design area of a fabricated solar cell has been analyzed with respect to its charge density. The mathematical calculation used for charge-density derivation was obtained from the 2001 version of a MATHCAD program. The parameter range for the calculations was ${\pm}1{\times}10^{17}cm^{-3}$, which is in the normal parameter range for n-type doping impurities ($7.0{\times}10^{17}cm^{-3}$) and also for p-type impurities ($4.0{\times}10^{17}cm^{-3}$). Therefore, it can be said that the fabricated solar-cell design area has a direct effect on charge-density changes.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1609-1611
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• 1994

In ECR and helicon reactors for plasma processing, a high density plasma is generated in a source region which is connected to a diffusion region where the processing takes place. Large density and potential gradients can develop at the orifice of the source which drive ion currents into the diffusion region. The average ion velocity may become the order of the sound velocity. Measurements of the ion saturation current to a Langmuir probe are used as a standard method of determining the plasma density in laboratory discharges. However, the analysis becomes difficult in a steaming plasma. We have used the HAMLET plasma simulator to simulate the ion flow to a large langmuir probe in an ECR plasma. The collection surface was aligned with the Held upstream, normal to the field, and downstream. ion trajectories through the electric and magnetic fields were calculated including ion-neutral collisions. We examines the ratio of ion current density to plasma density as a function of magnetic field and pressure.

• The Journal of the Korean Society for Microbiology
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• v.9 no.1
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• pp.41-45
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• 1974

On day 2 after treatment of Lewis rat with 25mg of hydrocortisone, the cell number in the thymus was reduced to less than 10% of the matched control. By day 12 after hydrocortisone treatment the thymic cell population was recovered almost its original value and on day 24 after treatment the number of thymocytes was equivalent to that of normal thymocytes. The density distribution profile of hydrocortisone treated rats as compared with normal rats showed a marked decrease in the denser fraction D while the lighter fractions. (A plus B, and C) showed a considerable proportional increase. The proportion of dead cells in thymus suspension from hydrocortisone treated rats was higher than that from their normal counterparts. On separation, the dead cells accumulated selectively in the pellet and A fraction. The response of the thymocytes from hydrocortisone treated rats to PHA was increased compared to that from normal rats. Among the subpopulations, D fraction, which was relatively unresponsive in normal rats, showed a marked increase in PHA response and C fraction showed some increase in the response.

• The Korean Journal of Applied Statistics
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• v.25 no.5
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• pp.803-811
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• 2012

For credit evaluation models, we extend the study of discriminatory power based on AUC obtained from a ROC curve when the number of defaults is small and distribution functions of the defaults and non-defaults are normal distributions. Since distribution functions do not satisfy normality in real world, the distribution functions of the defaults and non-defaults are assumed as normal mixture distributions based on results that the normal mixture could be better fitted than other distribution estimation methods for non-normal data. By using several AUC statistics, the discriminatory power under such a circumstance is explored and compared with those of normal distributions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.3
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• pp.253-258
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• 2015

The purpose of this study is to find suitable probability distribution function of complex distribution data like multimodal. Normal distribution is broadly used to assume probability distribution function. However, complex distribution data like multimodal are very hard to be estimated by using normal distribution function only, and there might be errors when other distribution functions including normal distribution function are used. In this study, we experimented to find fit probability distribution function in multimodal area, by using AIS(Automatic Identification System) observation data gathered in Mokpo port for a year of 2013. By using chi-squared statistic, gaussian mixture model(GMM) is the fittest model rather than other distribution functions, such as extreme value, generalized extreme value, logistic, and normal distribution. GMM was found to the fit model regard to multimodal data of maritime traffic flow distribution. Probability density function for collision probability and traffic flow distribution will be calculated much precisely in the future.