• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.291-294
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• 2005

In this study, we compared and analyzed the floor impact sound insulation performance produced by the rating methods. The rating methods are using reversed A-weighting curve, A-weighted sound pressure levels and arithmetic average. On-site floor impact sound pressure levels of living room and room are measured. The results of this study are 1)the rating using reversed A-weighting curve for heavy-weight impact sound's standard deviation is lower than that of light-weight impact sound, 2)the number of rating using A-weighted sound pressure levels and arithmetic average is larger than that of using reversed A-weighting curve, and 3)the number of rating using reversed A-weighting curve mainly depends on impact sound pressure level of 63Hz in heavy-weight impact sound.

• The Pure and Applied Mathematics
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• v.22 no.1
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• pp.25-34
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• 2015

In this paper we characterize the isogonal and isotomic conjugates of conic. Every conic can be expressed by a quadratic rational B$\acute{e}$zier curve having control polygon $b_0b_1b_2$ with weight w > 0. We show that the isotomic conjugate of parabola and hyperbola with respect to ${\Delta}b_0b_1b_2$ is ellipse, and that the isotomic conjugate of ellipse with the weight $w={\frac{1}{2}}$ is identical. We also find all cases of the isogonal conjugate of conic with respect to ${\Delta}b_0b_1b_2$. Our characterizations are derived easily due to the expression of conic by the quadratic rational B$\acute{e}$ezier curve in standard form.

• International Journal of Highway Engineering
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• v.6 no.3 s.21
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• pp.55-64
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• 2004

Maximum dry unit weight, ${\gamma}_{dmax}$, is the most important engineering properties for subgrade soil. Existing models to predict ${\gamma}_{dmax}$ containing many parameters, seem to be rather complex. This paper presents new simple models to predict ${\gamma}_{dmax}$. for sandy soils, A number of sieve analysis and compaction tests for 36 types of sands were conducted to develop the regression-based models. Parameters used to estimate ${\gamma}_{dmax}$ are both the geometric mean and geometric standard deviation of the soils, or the particle-size distribution curve parameters. Maximum dry unit weights predicted by the models are in good agreement with the laboratory measurements for the soil samples obtained at 16 locations within the Korea.

• Proceedings of the KSRS Conference
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• v.2
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• pp.772-775
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• 2006

Muilti-dimensional feature vector matching algorithm uses multiple features such as intensity, gradient, variance, first or second derivative of a pixel to find correspondence pixels in stereo images. In this paper, we proposed a new method for adjusting automatically the weight of feature in multi-dimensional feature vector matching considering sharpeness of a pixel in feature vector distance curve. The sharpeness consists of minimum and maximum vector distances of a small window mask. In the experiment we used IKONOS satellite stereo imagery and obtained accurate matching results comparable to the manual weight-adjusting method.

• Clinical and Experimental Pediatrics
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• v.48 no.11
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• pp.1179-1186
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• 2005

Purpose : A universal standard of the birth weight for gestational age cannot be made since girth weight distribution varies with race and other sociodemographic factors. This report aims to establish the birth weight distribution curve by gestational age, specific for Korean live births. Methods : We used the national birth certificate data of all live births in Korea from January 2001 to December 2003; for live births with gestational ages 24 weeks to 44 weeks(n=1,509,763), we obtained mean birth weigh, standard deviation and 10th, 25th, 50th, 75th and 90th percentile values for each gestational age group by one week increment. Then, we investigated the birth weight distribution of each gestational age group by the normal Gaussian model. To establish final standard values of Korean birth weight distribution by gestational age, we used the finite mixture model to eliminate erroneous birth slights for respective gestational ages. Results : For gestational ages 28 weeks 32 weeks, birth weight distribution showed a biologically implausible skewed tail or bimodal distribution. Following correction of the erroneous distribution by using the finite mixture model, the constructed curve of birth weight distribution was compared to those of other studies. The Korean birth weight percentile values were generally lower than those for Norwegians and North Americans, particularly after 37 weeks of gestation. The Korean curve was similar to that of Lubchenco both 50th and 90th percentiles, but generally the Korean curve had higher 10th percentile values. Conclusion : This birth weight distribution curve by gestational age is based on the most recent and the national population data compared to previous studies in Korea. We hope that for Korean infants, this curve will help clinicians in defining and managing the large for gestational age infants and also for infants with intrauterine growth retardation.

• The korean journal of orthodontics
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• v.4 no.1
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• pp.31-40
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• 1974

The age of maximum growth increments-the adolescent spurt-is not only of developmental interest but is used as a marker for timing other growth events. And the mandibular growth rate follows the general growth curve, it is essential for an orthodontist to take the current and exact information about physical growth of patients. The author measured and studied the body height and weight of 11,694 children living in Seoul, and calculated out the mean, standard deviation, coefficient value, annual increments, percentage increments of each value, and made diagram to compare it with others. 1. The growth curve shows linear increment tendency until 17 years of age in male, 15 years in female. 2. The annual increment curves of body height and weight reveals the most peak value in 14-16 years in male and 11-14 years in female. 3. During 11-14 years of age, female growth exceed the male growth in the body height growth. And in weight growth, female growth exceed the male growth during 6-7 years and 11-12 years to show twice crossing. 4. It seemed that until 11-12 years in male and until 9-10 years in female the height growth show the priority to weight growth. And from 17 years in male and 15 years in female the body growth reveals the balanced growth pattern. 5. The time of changes of standard deviation curves of body height and weight coincided with that of annual increments. 6. The prominent high value of body height and weight in the comparison with other data may be due to the secioeconomical and nutritional, environmental influence. 7. The growth accerlation phenomena was detectable.

• Journal of the Korean earth science society
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• v.38 no.2
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• pp.150-160
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• 2017

In order to determine the porosity of rock, the 'standard test method for porosity and density of rock' proposed by the Korean Society for Rock Mechanics is commonly used. However, the standard test method, which uses a drying oven, takes 8 to 24 hours to complete the test in taking samples out of the oven every four hours and measuring the weight of the specimen. To complement these disadvantages, we devised a method for measuring rock porosity by using a microwave oven. The devised method reduced the cause of errors and the inconvenience occurred in the process of weighing samples by constructing a weight monitoring system, which monitors the drying process. A suitable heating/pause time was set up to maintain the temperature of sample below $105{\pm}3^{\circ}C$ in drying process, and an alarm system was implemented in order to stop drying process when the weight change of the rock sample is within 0.1% of the initial weight. The porosity was determined from the dry weight of the sample, which was obtained by the curve fitting of weight monitoring data. Then, the porosities obtained by using the microwave oven were compared with those obtained by the standard test method. Test results using sandstone samples showed that the porosities obtained by a microwave oven was similar to those obtained by the standard method and the porosity difference between two methods was as large as 0.4%. In addition, repeated porosity measurement using the same specimen showed that the standard deviation of the porosity, which reflects the precision of the measurement was as good as 0.23%. Therefore, a microwave oven porosity measurement system can give the porosity of rock samples with high reliability.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.719-723
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• 2002

The purpose of this study is to suggest the correlation of single-number ratings for sound insulation by floor impact. As a assessment method of impact sound insulation. we selected the IIC contour of ISO, A weighted sound level. Inverse A-weighting curve and L-Index of japanese industrial standard. And we estimated the single-number ratings by application the measured data of impact sound level to each method. The results showed that the coefficients of determination between each two single-number ratings were very high (more than 0.9169). And In the condition of same assessment method, the coefficient of determination for light-weight impact sound was higher than that for heavy-weight impact sound.

• Journal of the Korean Society of Tobacco Science
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• v.27 no.2
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• pp.226-234
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• 2005

The uncertainty of measurement in nitrate from burley leaf tobacco by continuous-flow analysis method was evaluated following internationally accepted guidelines. The sources of uncertainty associated with the analysis of nitrate were weight of standard and sample, purity of standard, dilution of standard solution, calibration curve, water content, etc. The calculation of uncertainty based on the GUM(Guide to the Expression of Uncertainty in Measurement) and EURACHEM/CITAC Guide. An expanded uncertainty was obtained by multiplying the combined standard uncertainty with a coverage factor (k) calculated from the effective degree of freedom. The concentration of nitrate from burley leaf tobacco was $2.09\%$ and the expanded uncertainty by multiplying by the coverage factor(k, 2.20) was $0.13\%\;at\;a\;95\%$ confidence level.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1053-1059
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• 2003

This study aimed to determine the amount of vitamin C from vegetable & fruit juice by high performance liquid chromatograhy (HPLC). Components for estimation of measurement uncertainty associated with the analysis of vitamin C, such as standard weight, purity, molecular weight, dilution of standard solution, calibration curve, recovery, and precision, were importantly applied. The estimation of uncertainty obtained with systematic and random error based on the GUM (Guide to the expression of uncertainty in measurement) and EURACHEM document with mathematical calculation and statistical analysis. The components, evaluated ty either Type A or Type B methods, were combined to produce an overall value of uncertainty known as the combined standard uncertainty. An expanded uncertainty was obtained by multiplying the combined standard uncertainty with a coverage factor (k) calculated from the effective degree of freedom. The content of vitamin C from vegetable and fruit juice was 27.53 mg/100g and the expanded uncertainty by multiplying by the coverage factor (k, 2.06) was 0.63 mg/100g at a 95% confidence level. It was concluded that the main sources were, in order of recovery and precision, weight and purity of the reference material, dilution of the standard solution, and calibration curve. Careful experiments on other higher uncertainties is further needed in addition to better personal proficiency in sample analysis in terms of accuracy and precision.