• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.371-376
• /
• 2003

The objective of this paper is to compare the site-to-site variability of ISO 10844 pass-by-noise test sites. In order to investigate the site-to-site variance of test surfaces, European commercial tires are tested at seven different test sites. Three Korea test sites and four Europe test sites are selected.. The pass by noise test is executed according to a 2001/43/EC regulation. A]though the ISO surface has a very specific track composition, it does not reduce the variation of pass-by-noise measurements over the surface of test sites. This paper shows that the test results of pass-by-noise level are different depending on the test sites. The correlation obtained in this work is able to predict the pass by noise level for certain test site using the data measured from another test site. 17he prediction value is range with an error within 1dB(A).

• Journal of Plant Biology
• /
• v.9 no.1_2
• /
• pp.7-16
• /
• 1966

In order to determine the factors related to site quality, 13 areas of Larch growing in the Kwangung and its vicinity forest as sample plots, were examined. Sample plots included various site classes as well as age classes. Three were divided into two groups (major and minor trees). Average height of dominant trees was determined through messurement of 5 to 6 dominant tree in each sample plots. Average height of dominant 30 year-old trees was the basis for site index. A Standard Yield Table for the larch produced in Kwangnung forest was made by various data, which included age class 5, ranging from 10 to 45 years. The relationship of the height of the trees, the site conditions, and ground vegetation are investigated in this paper. The site indexes of 40 forest class age in 28-B and 28-G forest classes of the larch associations for ground vegetation had comparatively rarge differences due to the sampled areas. The relation of the direction of forest communities to the height and the diameter of the tree shwoed that its communiteis of northest and northwest parts appeared higher valueof the height and the diameter. The diameter and the height of trees were closely realted to each other. The samller the occupied area per tree and the smaller the average distance among trees, the more density was increased. The larger the density was the lower height of the trees. In the ground vegetation of the larch communities, there seems to be a definite correlation between the height of trees and the occupied area per tree or the average distance among the trees. The height of trees and site index of two larch communities were as follow: 28-B forest class site index 20.8, height 24.0m, 28-G forest class site index 18.4, height 20.9m. The ground layer was analyzed by the method of Quadrat(20/20sq. cm) with an interval of 1M. It set up 40 Quadrats of the larch communiteis. The community structure of the ground vegetation of two larch was analyzed, and important value was calculated and then evaluated. The ground vegetation under the larch had developed Burmannii Beauv stratal society below the 28-B and 28-G the forest class. Accordingly, the first important value of Burmannii Beauv was found in two ground vegetation below the larch. Therefore, this species could be quantitatively considered as the forest indicator species. Common species of each community appeared 18 species out of 34 species in the ground vegetation under two larch communities. The ground vegetation of the 28-B forest class showed more than that of the 28-G forest class. the similarity of the ground vegetation was measrued by the Frequency Index Community Coefficient. The differences between the associations were lcearly manifested by the ground vegetation tested by Gleason's Frequency Index of Community Coefficient for the analysis of each stratal society of all associations. According to F.I.C.C. the ground vegetation under two larch(28-B and 28-G) forest classes showed higher value. An investigation into the relationship of physical and chemical properties of soil and site was considered the next step to be taken in the study of the larch site classification.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.04a
• /
• pp.417-422
• /
• 2000

In prestressed concrete structures, determining serviceability and safety it is important to exactly calculate effective prestress force acting on structures. for the determination of effective prestress force, friction loss of the prestressing tendon should be decided exactly, but it is very difficult to measure the exact prestress force on the site and there is no actual field data. Therefore the friction loss coefficient recommended by the specification is not verified. in this paper, the friction loss standard PSC-Beam will be investigated, and is will be found what kind of relationship between the specification and the site. The results from this study can be summarized as follows. For jacking at both ends, actual intial prestress force in the center section of PCS-Beam was about 1.61% larger than theoretical initial prestress force and for hacking at one end, actual initial prestress force was approximate 4.9% lower than theoretical initial prestress force. Thus, for the exact calculation of friction loss, friction coefficient should be modified according to jacking methods.

• Water for future
• /
• v.27 no.1
• /
• pp.133-140
• /
• 1994

The augmenting hydrologic data using a correlation procedue has been used to improve the estimates of the mean and variance at the site of interest with short record when one or more nearby sites with longer records are available. The variance of the unbiased maximum likelihood estimator of ${{\sigma}_v}^2$ derived by Moran based on the multivariate normal distribution is modified into the form of Matalas and jacobs for the bivariate normal distribution to get the critical minimum values of the multiple correlation coefficient which give the improvement for estimation the variance at the site of interest. Those values are tabulated for various lengths of records and the number of sites.

• Journal of the Korean Solar Energy Society
• /
• v.33 no.5
• /
• pp.1-8
• /
• 2013

Wind resource data of short-term period has to be corrected a long-term period by using MCP method that Is a statistical method to predict the long-term wind resource at target site data with a reference site data. Because the field measurement for wind assessment is limited to a short period by various constraints. In this study, 2 different MCP methods such as Linear regression and Matrix method were chosen to compare the predictive accuracy between the methods. Finally long-term wind speed, wind power density and capacity factor at the target site for 20 years were estimated for the variability of wind and wind energy. As a result, for 20 years annual average wind speed, Yellow sea off shore wind farm was estimated to have 4.29% for coefficient of variation, CV, and -9.57%~9.53% for range of variation, RV. It was predicted that the annual wind speed at Yellow sea offshore wind farm varied within ${\pm}10%$.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.53 no.6
• /
• pp.137-144
• /
• 2011

We have examined the pollutant load of combined sewer in dry days. Two monitoring sites (C-1, C-2) were equipped with an flowmeter. Monitoring was conducted from September 2004 to April 2006 for 20 months during dry days. Flowrate and concentration of pollutants are lowest from 3 to 6 o'clock, and it is high at 9, 12 and 21 o'clock. Most of organic matters exist in the dissolved state. The results show that pollution loads in C-2 area were 4.5-7.2 times higher than in C-1. Pollutant loads were high on Saturdays. Pollutant loads (kg/ha/day) of C-2 were 1.1-3.1 times higher those of C-1. However there was no significant difference in winter. Analysis of correlation coefficient of water quality parameter indicates that besides of flowrate all items in C-1 site have tight relationship respectively (p<0.01). In C-2 site, correlation coefficient of TP-SS, TP-TN, TP-flowrate, BOD-flowrate, BOD-SS and TN-TP are statistically significant (p<0.01).

• Land and Housing Review
• /
• v.6 no.3
• /
• pp.147-152
• /
• 2015

Site coefficient and amplification factor of current domestic Seismic Design Code based on American Seismic Code, have no consideration for the domestic ground condition in which the base rock is normally placed within 30m form the surface. By previous studies, the measured spectral acceleration of the result of dynamic centrifugal test and analysis was smaller than the design spectral acceleration for the period over 1.5 sec. Accordingly, in this study structural analysis and design using dynamic centrifugal test result for pile foundation were achieved, and the quantity of concrete and reinforcement of wall frame was compared with each other. Comparison results of cost using KBC the design spectral acceleration of SC, SD site and SDS, the quantity of reinforcement using SDS for SD site was 17~23% smaller than using the design code SD site.

• Journal of the Korean GEO-environmental Society
• /
• v.8 no.4
• /
• pp.47-55
• /
• 2007

Using the results of the Piezocone Penetration Test (PCPT) which were executed at the Yangsan-Mulgum site, the applicability of the interpretation methods for estimating the coefficient of consolidation ($C_v$) of soft clay was evaluated. At the same time, laboratory soil tests using the total of 172 undisturbed soft clay samples from the 44 regions of the Yangsan-Mulgum site were performed to study the differency in the coefficient of consolidation ($C_v$) compared to the results of PCPT. The calculated constrained modulus ($M_{\varepsilon}$) and coefficient of consolidation ($C_v$) using the results of consolidation laboratory tests which are based upon the consolidation theory of Terzaghi were compared with the predicted constrained modulus ($M_p$) and coefficient of consolidation ($C_{v-{M_p}}$) from the PCPT. The relationship between the predicted constrained modulus ($M_p$) and the calculated constrained modulus($M_c$) were showed good correlation. The $M_p$ by the Jones & Rust method were showed mostly similar to the calculated constrained modulus ($M_c$). The relationship between the coefficient of consolidation ($C_v$) obtained from the consolidation tests and the calculated coefficient of consolidation ($C_{v-{M_p}}$) were showed a linear relationship. The results of the calculated coefficient of consolidation ($C_{v-{M_p}}$) were about 54% of the value of the coefficient of consolidation ($C_v$) obtained from the consolidation tests.

• Journal of the Korean GEO-environmental Society
• /
• v.14 no.3
• /
• pp.13-17
• /
• 2013

Determination of geotechnical characteristics of soil is either to use the field samples to measure the characteristics of soil through laboratory test or measuring the characteristics directly in the field. Field test can be derived similar value by considering characteristics of site and laboratory test can be confirmed the characteristic of soil by testing with field samples. This article describes relative density as the measure of compaction for cohesionless soils and presents several simple and mathematical relationships to help engineers estimate needed parameters for relative density calculations. The main purpose of this research is to investigate possible correlations between coefficient of uniformity, coefficient of curvature, maximum and minimum void ratio, mean grain size. Results show a linear relationship between the minimum and maximum void ratios and a power function relationship between coefficient of uniformity and the limiting void ratios. Void ratio range, which is the difference between the maximum and minimum void ratios, appeared to be log normally distributed but showed no simple mathematical fit to the data. these results were shown to help engineers estimate needed parameters for relative density calculations.

• Journal of the Korean Ceramic Society
• /
• v.33 no.9
• /
• pp.1019-1023
• /
• 1996

The dielectric properties at microwave frequencies of B site complex perovskite La(Zn1/2Ti1/2)O3 which has +3 ion in A site were investigated. maximum Q*F value of the specimens was 59000 dielectric constant 34, temperature coefficient of resonant frequency -52 ppm/$^{\circ}C$. XRD pattern of the sintered specimen shows (111) ssuperlattice reflection which indicates Zn and Ti cation ordering.