• Journal of the Korean Ceramic Society
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• v.33 no.5
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• pp.547-555
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• 1996

Porous alumina ceramics were fabricated by pseudo-boehmite phydosol-gel process within/without commercial $\alpha$-alumina particles average 1 and 40 micron respectively. The pore characteristics of fired specimens were studied by the measurement of bulk density total porosity thyermal analysis pore volume pore distribution BET area XRD and SEM. with increasing of firing temperature pore volume and BET surface area were decreased and the average pore size was increased to approximately 146$\AA$ upto 80$0^{\circ}C$ by de-watering of [OH] and formation of $\alpha$-alumina. The fired relative density of the alumina-dispersed specimen with average 1 micron particle was increased with the amounts of dispersed particle by bimodal packing theory which is compared to the ones of specimen including of average 40 micron particle. It was confirmed that the percola-tion threshold in porous ceramics with coarser particle (40 micron) has formed between the transformed-alumina from hydrogel and dispersed-alumina of above 50 vol% particle and the total porosity was increased at the threshold point above.

• Communications for Statistical Applications and Methods
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• v.17 no.2
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• pp.223-229
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• 2010

We consider the asymptotic results of the variance ratio statistic when the underlying processes have moving average(MA) unit roots. This degenerate situation of zero spectral density near the origin cause the limit of the variance ratio to become zero. Its asymptotic behaviors are different from non-degenerating case, where the convergence rate of the variance ratio statistic is formally derived.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.1
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• pp.37-44
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• 2009

Density is the most important congestion indicator among the three fundamental flow variables, flow, speed and density. Measuring density in the field has two different ways, direct and indirect. Taking photos with wide views is one of direct ways, which is not widely used because of its cost and lacking of proper positions. Another direct density measuring method using two spot detectors has been introduced with the concept of instantaneous density, average density and measurement interval. The relationship between accuracy and measurement interval has been investigated using the simulation data produced by Paramics API function. Finally, density measurement algorithm has been suggested including exponential smoothing for device development.

• Journal of Nutrition and Health
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• v.38 no.7
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• pp.544-552
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• 2005

This study was conducted to examine the correlation among bone mineral density (BMD), hair and nail calcium and magnesium contents, and nutrient intakes in preschool children in Chungnam district. A total of 111 preschool children (61 boys, 50 girls) measured the anthropometric characteristics, the bone mineral density of carpus using DEXA and hair and nail calcium and magnesium contents were analyzed by ICP spectrometer. The average ages of the study subjects were 55.7 months in boys and 53.0 months in girls (3.8${\~}$7 years). The birth height and weight of subjects were 51.0 cm and 3.3 kg in boys and 50.3cm and 3.2kg in girls, respectively. The average height, weight, $\%$ body fat, and obesity index were 111.6 cm, 19.6 kg, $15.0\%,\;96.1\%$ in boys and 108.6 cm, 18.5 kg, $17.5\%,\;98.1\%$ in girls, respectively. The bone mineral density in carpus was $0.25 g/cm^2$ in boys and $0.24 g/cm^2$ in girls. The hair calcium and magnesium contents were 440.9 ppm, 16.4 ppm in boys and 373.2 ppm, 28.9 ppm in girls. The nail calcium and magnesium contents were 9.4 ppm, 2.1 ppm in boys and 10.4 ppm, 2.4 ppm in girls. The intakes of energy, calcium, iron, zinc, vitamin A. niacin, and vitamin C did not meet the Korean RDAs. The ultradis and average carpus BMD were positively correlated to the plant calcium intake (p < 0.05, p < 0.05). And the ultradis, distal, and average carpus BMD were positively correlated to the plant iron intake (p < 0.05, p < 0.05, p < 0.05). The average bone mineral density in the carpus was positively correlated to the nail magnesium content (p < 0.05). Therefore, more systematic studies to investigate the roles of iron and calcium intakes, nail magnesium content in bone development of preschool children were required.

• Journal of Nutrition and Health
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• v.36 no.5
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• pp.470-475
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• 2003

The purpose of this study was to investigate the effect of isoflavone supplementation using soymilk on bone mineral density in underweight college women aged 19-22 years with lower than average bone mass. The bone mineral density (BMD) of the lumbar spine and femoral neck of a number of underweight (BMI < 20) college women was measured. From this group, 33 subjects whose T-score value was below -1 were selected. Anthropometric measurements, dietary recall and BMD were measured before the study began and at the end of the 10th week. The 33 subjects were given 400 ml of soymilk containing 60 mg of isoflavones daily for 10 weeks. After 12 weeks at the end of 10 weeks treatment, the BMD of the subjects was reassessed. The average age of the subjects was 21.1 yrs. At the baseline, average height, weight, and BMI of the subjects were 161 cm, 49.1 kg, 18.8 kg/$m^2$, respectively. Mean daily intake of energy and protein was 1637.2 kcal and 61.2 g, respectively. Mean dietary isoflavone intake was 17.4 mg. Despite the 400 ml soymilk supplementation, there was no significant change in nutrient intake after the 10-week treatment. However, there were significant increases in lumbar spine and femoral neck BMD. After the study, the BMD of the subjects' spine and femoral neck was lower than that before the study. In conclusion, soymilk intake was associated with a significant increase in the BMD of the lumbar spine and femoral neck in underweight college women with lower than average bone mass. (Korean J Nutrition 36(5): 470~475, 2003)

• Journal of Korean Society of Forest Science
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• v.81 no.2
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• pp.139-145
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• 1992

A planning method of optimum forest road was tested in the compartment II of Kangweon National University Forests by using a digital terrain model under four evaluation factors, i. e., minimum road length, average skidding distance, exploitative index, and ratio of inaccessible points. The results of the study were as follows : 1. Optimum forest road design based on the minimum road length was shown as 6035.6m, 12.73m/ha, 279.9m, 1.43, and 15.7% for total road length, forest road density, average skidding distance, exploitative index, and ratio of inaccessible points, respectively. 2. Optimum forest road design based on the average skidding distance was shown as 7828.5m, 16.52m/ha, 198.4m, 1.31, and 4.0% for total road length, forest road density, average skidding distance, exploitative index, and ratio of inaccessible points, respectively. 3. Optimum forest road design based on the exploitative index was shown as 7410.6m, 15.64m/ha, 210.9m, 1.26, and 5.0% for total road length, forest road density, average skidding distance, exploitative index, and ratio of inaccessible points, respectively. 4. Optimum forest road design based on the ratio of inaccessible points was shown as 8307.1m, 17.53 m/ha, 184.9m, 1.29, and 2.5% for total road length, forest road density, average skidding distance, exploitative index, and ratio of inaccessible points, respectively.

• Journal of Surface Science and Engineering
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• v.24 no.2
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• pp.88-95
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• 1991

The tin-lead alloy was electrodeposited in the low range of peak current density in order to investigate the change of composition and microstructure of them. The Pb content of alloy deposits, which was decreased with increasing average current density, was relatively lower than that of D.C. plated alloy deposit. The preferred orientation of alloy deposit was changed with increasing peak current density and the surface morphology of alloy deposits was closely related to the preferred orientation of them.

• Journal of the Korean Society of Safety
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• v.34 no.1
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• pp.1-7
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• 2019

Electromagnetic measurements of the power cable tunnel were conducted from August 10 to 20, 2018, in the ${\bigcirc}{\bigcirc}$ city underground utility tunnel. During this period, the average temperature was $31.89^{\circ}C$ and the humidity was 67.56% in power cable tunnel. As a result of the electromagnetic measurement, the highest electric field was 25.3 V/m and the magnetic flux density was $42.6{\mu}T$. The average electric field was 18.56 V/m and the magnetic flux density was $29.32{\mu}T$ in the power cable tunnel. As a result of comparison with the electric equipment technical standard, the electric field in the power cable tunnel was 0.5% of the electric equipment standard and 35.2% of the magnetic flux density. It's similar value that electric field is about robotic vacuum(15.53 V/m), and magnetic flux density is similar value about capsule- type coffee machine ($23.07{\mu}T$). The number of cable lines and the size of the electromagnetic waves were not proportional to each other through comparison of cable lines in the power cable tunnel. It was confirmed that 154 kV, rather than 22.9 kV, could have a greater influence on occupational.

• Journal of Forest and Environmental Science
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• v.30 no.3
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• pp.259-266
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• 2014

Stand Density Diagrams (SDD) are average stand-level models which graphically illustrate the relationship between yield, density and mortality throughout the various stages of forest development. These are useful tools for designing, displaying and evaluating alternative density regimes in even-aged forest ecosystems to achieve a desired future condition. This contribution presents an example of a SDD that has been constructed for teak forests of Karnataka in southern India. The relationship between stand density, dominant height, quadratic mean diameter, relative spacing and stand volume is represented in one graph. The relative spacing index was used to characterize the population density. Two equations were fitted simultaneously to the data collected from 27 sample plots measured annually for three years: one relates quadratic mean diameter with stand density and dominant height while the other relates total stand volume with quadratic mean diameter, stand density and dominant height.

• Korean Journal of Community Nutrition
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• v.10 no.1
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• pp.91-100
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• 2005

This study was conducted to investigate the effects of smoking on nutrition intake, bone mineral density and blood mineral status. The subjects were composed of two groups: 100 smokers and 100 non-smokers was used along with a questionnaire. Anthropometric measurements, dietary intakes using 24-hours recall method were compared. At twenty subjects from each group were selected, bone mineral density were measured by quantitative ultrasound and plasma mineral levels were analyzed by ICP spectrometer. The average ages of smokers and non-smokers were 23.9 and 22.8 years old, respectively. The height, weight and BMI of the smokers were no significant difference. The average numbers of smoked cigarettes were 11.8/d and the average packyear was 3.1 in the smokers. About $97\%$ of the smokers drank alcoholic beverages, while $85\%$ of the non-smokers did. The smokers tended to eat less meals and dinner meal, but drink coffee more often compared to the non-smokers. The mean daily energy intake and CPF energy intake ratio were 2184. 9 kcal and 57.2 : 13.7 : 26.4 in the smokers and 2262.6 kcal and 55.8 : 13.1 : 28.6 in the non-smokers. The smokers consumed significantly lower intake of $\beta$-carotene. There were no significant differences in bone mineral density of BUA, SOS and QUI. There were no significant differences in plasma levels of Ca, Mg, Fe and Zn. However, plasma Cu level of the smokers was significantly higher than that of the non-smokers. In conclusion, the smokers of this study showed a more undesirable dietary intake in the light of their low ,B -carotene and high alcoholic beverages, and coffee. The plasma Cu level of the smokers was higher than that of the non-smokers, showing that Cu is involved in smoking. Therefore, it could be suggested that more systematic research be conducted with respect to Cu and smoking and that increased nutrition education and guidelines for smokers are required.