• Journal of the Korean institute of surface engineering
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• v.25 no.4
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• pp.165-172
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• 1992

Filler, popularly used in the polymer materials, was dispersed randomly and irregularly. For the study of dispersed behavior, the specimen which have two particles in polystyrene was prepared. And the tensile strength, modulus and SEM picture were measured. When the distance between particles increased, the tensile strength and modulus increased, but particle size did not affect the values. And when the am-bient temperature increased, the tensile strength and modulus decreased, but the distance did not affect the tensile strength and modulus.

• Journal of Astronomy and Space Sciences
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• v.24 no.3
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• pp.203-208
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• 2007

We report the distance modulus of nearby dwarf elliptical galaxy NGC 147 estimated from the Tip of Red-giant Branch (TRGB) method applying to the color-magnitude diagrams and luminosity functions in the near-infrared JHK bands. Apparent magnitudes of TRGBs in each band are obtained by applying Savitzky-Golay filter to the luminosity functions, and the theoretical absolute magnitudes are estimated from Yonsei-Yale isochrones. The derived values of distance modulus to NGC 147 are $(m-M)=23.69{\pm}0.12,\;23.78{\pm}0.17,\;and\;23.85{\pm}0.22\;for\;J,\;H,\;and\;K$ bands, respectively. Distance modulus in bolometric magnitude is also derived as $(m-M)=23.87{\pm}0.11$. We compare the derived values of the TRGB distance modulus to NGC 147 in the near-infrared bands with the previous results in other bands.

• Journal of Astronomy and Space Sciences
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• v.25 no.3
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• pp.245-248
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• 2008

We determined values of distance modulus to nearby dwarf galaxy NGC 185 from the Tip of Red-Giant Branch (TRGB) method. Apparent magnitudes of the TRGB are estimated from the near-infrared JHK luminosity functions (LFs) of the resolved giant branch stars. Theoretical absolute magnitudes of the TRGB in near-infrared bands have been extracted from the Yonsei-Yale isochrones. The observed apparent and theoretical absolute magnitudes of the TRGB provide values of distance modulus to NGC 185 as (m - M) = $23.39{\pm}0.14$, $23.23{\pm}0.22$, and $23.27{\pm}0.26$ for J,H, and K bands, respectively. Distance modulus in bolometric magnitude is also derived as (m - M) = $23.62{\pm}0.12$.

• Journal of Astronomy and Space Sciences
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• v.25 no.3
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• pp.249-254
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• 2008

We report the distance modulus of nearby dwarf irregular galaxy NGC 6822 estimated from the so-called Tip of Red-giant Branch (TRGB) method. To detect the apparent magnitudes of the TRGB we use the color-magnitude diagrams (CMDs) and luminosity functions (LFs) in the near-infrared JHK bands. Foreground stars, main-sequence stars, and supergiant stars have been classified on the (g - K, g) plane and removed on the near-infrared CMDs, from which only RGB and AGB stars are remained on the CMDs and LFs. By applying the Savitzky-Golay filter to the obtained LFs and detecting the peak in the second derivative of the observed LFs, we determined the apparent magnitudes of the TRGB. Theoretical absolute magnitudes of the TRGB are estimated from Yonsei-Yale isochrones with the age of 12Gyr and the metallicity range of -2.0 <[Fe/H]< -0.5. The derived values of distance modulus to NGC 6822 are (m - M) = $23.35{\pm}0.26$, $23.20{\pm}0.42$, and $23.27{\pm}0.50$ for J, H, and K bands, respectively. Distance modulus in bolometric magnitude is also derived as (m - M) = $23.41{\pm}0.17$. We compare the derived values of the TRGB distance modulus to NGC 6822 in the near-infrared bands with the previous results in other bands.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.4
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• pp.295-299
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• 2011

Blind equalization techniques have been widely used in wireless communication systems. In this paper, we propose to apply the balanced information potentials to the criterion of minimum Euclidian distance between two PDFs with constant modulus errors for adaptive blind equalizers. One of the two PDFs is constructed with constant modulus error samples and another does with Dirac delta functions. Two information potentials derived from the criterion are balanced in order to have better performance by putting a weighting factor to each information potentials. The proposed blind algorithm has shown in the MSE convergence performance that it can produce enhanced performance by over 3 dB of steady state MSE.

• Journal of Internet Computing and Services
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• v.10 no.6
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• pp.19-26
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• 2009

In this paper, a minimum Euclidian distance criterion between error PDF and Dirac delta function is introduced and a constant modulus type blind equalizer algorithm based on the criterion is proposed. The proposed algorithm using constant modulus error in place of actual error term of the criterion has superior convergence and steady state MSE performance, and the error signal of the proposed algorithm exhibits more concentrated density function in blind equalization environments. Simulation results indicate that the proposed method can be a reliable candidate for blind equalizer algorithms for multipoint communications.

• Journal of Industrial Technology
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• v.22 no.A
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• pp.185-192
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• 2002

The performance of old and the new concrete construction depends upon bond strength between old and the new concrete. Current adhesive and strength measurement method ignores the effect of stress concentration from shape of specimens. Therefore, this research calculates stress concentration coefficient as the ratio of drilling depth to drilling diameter($h_s/D$), the ratio of overlay thickness to drilling diameter($h_0/D$), the ratio of steel disk thickness to drilling diameter(t/D), the ratio of overlay elastic modulus to substrate modulus($E_1/E_0$), the distance from core to corner border(L_$_{corner}$) and the distance between cores(L_$_{coic}$) vary. The finite element method is adapted to analysis The results from 'the F.E.M analysis are as follows. The stress concentration effects can be minimized when the ratio of drilling depth to drilling diameter($h_s/D$) is 0.20~0.25, the elastic modulus ratio($E_1/E_0$) is 06~1.0, and the ratio of steel disk thickness to drilling diameter(t/D) is 3.0. The overlay thickness, the distance from specimens to corner border(L_$_{corner}$), the distance between cores(L_$_{coic}$) almost do not affect to the stress concentration.

• Geomechanics and Engineering
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• v.22 no.4
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• pp.339-348
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• 2020

The uncertain geotechnical properties of frozen soil are important evidence for the design, operation and maintenance of the frozen ground. The complex geological, environmental and physical effects can lead to the spatial variations of the frozen soil, and the uncertain mechanical properties are the key factors for the uncertain analysis of frozen soil engineering. In this study, the elastic modulus, strength and Poisson ratio of warm frozen soil were measured, and the statistical characteristics under different temperature conditions are obtained. The autocorrelation distance (ACD) and autocorrelation function (ACF) of uncertain mechanical properties are estimated by random field (RF) method. The results show that the mean elastic modulus and mean strength decrease with the increase of temperature while the mean Poisson ratio increases with the increase of temperature. The average values of the ACD for the elastic modulus, strength and Poisson ratio are 0.64m, 0.53m and 0.48m, respectively. The standard deviation of the ACD for the elastic modulus, strength and Poisson ratio are 0.03m, 0.07m and 0.03m, respectively. The ACFs of elastic modulus, strength and Poisson ratio decrease with the increase of ratio of local average distance and scale of fluctuation. The ACF of uncertain mechanical properties is different when the temperature is different. This study can improve our understanding of the spatial autocorrelation variations of uncertain geotechnical properties and provide a basis and reference for the uncertain settlement analysis of frozen soil foundation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8A
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• pp.760-767
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• 2010

For complex channel blind equalization, this study presents the performance and characteristics of two complex blind information theoretic learning algorithms (ITL) which are based on minimization of Euclidian distance (ED) between probability density functions compared to constant modulus algorithm which is based on mean squared error (MSE) criterion. The complex-valued ED algorithm employing constant modulus error and the complex-valued ED algorithm using a self-generated symbol set are analyzed to have the fact that the cost function of the latter forces the output signal to have correct symbol values and compensate amplitude and phase distortion simultaneously without any phase compensation process. Simulation results through MSE convergence and constellation comparison for severely distorted complex channels show significantly enhanced performance of symbol-point concentration with no phase rotation.

• Journal of The Korean Astronomical Society
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• v.32 no.2
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• pp.91-107
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• 1999

We present BVRI CCD photometry and near-infrared K photometry of the intermediate-aged open cluster NGC 7790. The reddening, E(B - V) = 0.54 $\pm$ 0.05 and the distance modulus, (m - M)o = 12.45 $\pm$ 0.10 for the cluster were determined by zero-age-main-sequence fitting and theoretical isochrone fitting using not only (V, B - V), (V, V - 1), (V, V - R) but also (V, V - K) color-magnitude diagrams. The reddening corresponded approximately to the average value derived from previous studies, while the distance modulus was found to be almost midway between the CCD photometric results of Romeo et al. (1989) and those of Mateo & Madore (1988). We have used four colors to distinguish members from field stars. The expected colors were calculated using the derived distance modulus, and were then were compared with the observed colors (B - V), (V - 1), (V - R), and (V - K). Thus, a color excess E(B - V) for each star was determined which could give the minimum difference between the calculated and observed colors. Single and binary members of the cluster were determined on the basis of the E(B - V) distribution of stars.