• Geotechnical Engineering
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• v.9 no.3
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• pp.61-66
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• 1993

In this paper, the incorporation of qualitative(or soft) data, such as outputs of geophysical tests or construction experience which has so far been cumulated, was discussed for rock classsification. Geostatistics wart used for this research since the parameters for the design of tunnels are spatially correlated. In particular, indicator kriging technique, which is one of non -parametric approaches, was used. As a selection criteria for an optimal classification, the cost of errors was adopted and the binary classes were only considered for rock classification. In future, incorporating an appreciable amount of available qualitative data will be necessary in tunnelling projects in which quantitative data are scarce. In this respect, this research is of great significance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.63-67
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• 2009

The previous work (Cheong et al., 2006) where the characteristics of acoustic emissions of wind turbines has been investigated according to the methods of power regulation, has showed that the acoustic power of wind turbine using the stall control for power regulation is more correlated with the wind speed than that using the pitch control. In this paper, basically extending this work, the noise generation characteristics of large modern upwind wind turbines are experimentally indentified according to the power regulation methods. To investigate the noise generation mechanisms, the distribution of noise sources in the rotor plane is measured by using the Beam-forming measurement system (B&K 7768, 7752, WA0890) consisting of 48 microphones. The array results for the 660 kW wind turbine show that all noise is produced during the downward movement of the blades. This result show good agreement with the theoretical result using the empirical formula with the parameters: the convective amplification; trailing edge noise directivity; flow-speed dependence. This agreement implies that the trailing edge noise is dominant over the whole frequency range of the noise from the 660 kW wind turbine using the pitch control for power regulation.

• Journal of Communications and Networks
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• v.7 no.4
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• pp.450-461
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• 2005

In this paper, we derive analytical expressions for the exact pairwise error probability (PEP) of a space-time coded system operating over spatially correlated fast (constant over the duration of a symbol) and slow (constant over the length of a code word) fad­ing channels using a moment-generating function-based approach. We discuss two analytical techniques that can be used to evaluate the exact-PEPs (and therefore, approximate the average bit error probability (BEP)) in closed form. These analytical expressions are more realistic than previously published PEP expressions as they fully account for antenna spacing, antenna geometries (uniform linear array, uniform grid array, uniform circular array, etc.) and scattering models (uniform, Gaussian, Laplacian, Von-mises, etc.). Inclusion of spatial information in these expressions provides valuable insights into the physical factors determining the performance of a space-time code. Using these new PEP expressions, we investigate the effect of antenna spacing, antenna geometries and azimuth power distribution parameters (angle of arrival/departure and angular spread) on the performance of a four-state QPSK space-time trellis code proposed by Tarokh et al. for two transmit antennas.

• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.114-119
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• 2006

This paper reports the investigation results on the leakage currents (LC) on polymeric outdoor insulators. The samples used were EPDM (ethylene prophylene diene monomer) insulators used at 20 kV distribution lines. AC voltage was applied and the LC waveforms were measured under various environmental conditions (humidity and pollution). Digital data of the LC was transferred from a digital storage oscilloscope to a computer for further analysis. The LC waveform parameters such as magnitude and harmonic content (as indicated by the total harmonic distortion (THD)) were analyzed. The experimental results showed that 3rd, 5th and 7th harmonics and higher odd harmonics were observed for symmetrical-distorted LC waveforms while for unsymmetrical-distorted LC waveforms, odd and even harmonics were observed. The LC analysis indicated that there are 5 stages of insulator conditions from normal condition up to flashover correlated with different kind of LC waveforms. The results also showed that in general the magnitude of LC was good enough to show the condition of the insulators. However, under discharge condition (for example as a result of dry band arching) the LC magnitude should be combined by the THD to show a better correlation with the insulator condition. The product between THD and LC magnitude may be used as a diagnostic parameter.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.67-71
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• 2010

In this paper, channel capacity analysis is investigated for design of convergence system of broadcasting and telecommunication. To do this, we derive and analyze channel capacity of the proposed system with dual-branch MRC diversity technique in correlated Hoyt fading channel. Spread spectrum watermarking scheme which is known as a robust promising technique in noisy environment can be applied to transmit additional data sequence. From numerical results, we confirm that the channel capacity of the proposed system can be determined by channel parameters.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.72.2-72.2
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• 2012

We present the results of HI 21 cm line observations to explore the nature of the high-velocity (HV) HI gas at - 173${\circ}$, which appears as faint, wing-like, Hi emission that extends to velocities beyond those allowed by Galactic rotation in the low-resolution surveys. We designate this feature as Forbidden Velocity Wing (FVW) 172.8+1.5. Our high-resolution Arecibo HI observations show that FVW 172.8+1.5 is composed of knots, filaments, and ring-like structures distributed over an area of a few degrees in extent. These HV HI emission features are well correlated with the HII complex G173+1.5, which is composed of five Sharpless HII regions distributed along a radio continuum loop of size 4.4${\times}$3.4, or -138 pc ${\times}$ 107 pc, at a distance of 1.8 kpc. G173+1.5 is one of the largest star-forming regions in the outer Galaxy. The HV HI gas and the radio continuum loop seem to trace an expanding shell. Its derived HI parameters including large expansion velocity (55 km/s) imply the SNR interpretation. Hot xray emission is detected within the HII complex, which also supports its SNR origin. The FVW172.8+1.5 is most likely the products of a supernova explosion(s) within the HII complex, possibly in a cluster that triggered the formation of these HII regions.

• 한국가시화정보학회:학술대회논문집
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• 2003.11a
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• pp.67-70
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• 2003

Hard disk drives (HDD) in computer are used extensively as data storage capacity. The trend in the computer industry to produce smaller disk drives rotating at higher speeds requires an improved understanding of fluid motion in the space between disks. Laser sheet and digital camera was used for 2-dimensional visualization of the unsteady flow between the center pair of two co-rotating disks in air with a cylindrical enclosure (or shroud). Geometric parameters are gap height (H) between disks, and gap distance (G) between disk tip and shroud. The lobe-structured boundary between inner region and outer region was detected by inserted particles, and the number of dominant vortices was determined clearly It is found from flow visualization that the number of vortex cells can be correlated with Reynolds number based on H which is defined as $Re_H={\Omega}RH/v$ ranging from $3.18\times10^3\;to\;1.43\times10^4$, and decreases as the disk speed increases. The lobe pattern by vortex cells is changed to a circular pattern for the wide gap than narrow one.

• The Korean Journal of Nuclear Medicine
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• v.3 no.2
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• pp.33-38
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• 1969

The serum thyroxine levels were measured by method of Tetrasorb Kit in 69 subjects including 13 subjects in euthyroid state, 31 with hyperthyroidism, 5 with hypothyroidism, 13 with nontoxic diffuse goiter, and 7 with nontoxic nodular goiter. Three parameters of the thyroid function test including thyroxine ($T_4$) levels, $^{131}I$ uptake (24 hrs) values and $PB^{131}I$ conversion ratio were correlated with clinical manifestations and courses of the disease. 1. The serum $T_4$ levels in the normal subjects were in range of $6.0{\mu}g/dl\;to\;14.4{\mu}g/dl$. (The mean $9.4{\mu}g/dl$). 2. The diagnostic compatibility of the serum $T_4$ was 93.5% in hyperthyroidism, 100% both in hypothyroidism and in nontoxic diffuse goiter, 86% in nontoxic nodular goiter, or 95.8% in the entire series. (Table 1). 3. The diagnostic compatibility of $^{131}I$ uptake (24 hrs) values and $PB^{131}I$ conversion ratio were less than the serum $T_4$ levels as summarized in Tables 2 & 3. The serum $T_4$ determination by Tetrasorb Kit is a simple, accurate and very useful test of the thyroid function.

• Food Science and Biotechnology
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• v.15 no.6
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• pp.931-936
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• 2006

This study sought to investigate any additive or interactive effects that soy isoflavones may have on the ecosystem of the gut, which is influenced by fructooligosaccharide (FOS) in colon-cancer model rats. Male Sprague-Dawley rats treated with 1,2-dimethylhydrazine were given experimental diets containing 0, 3, 6, or 9% FOS with or without 0.1% soy isoflavone for 12 weeks. In addition to the effects of FOS dosage on the gut ecosystem, dietary supplementation with soy isoflavone reduced the number of colonic aberrant crypts (ACs). The fecal weight, fecal pH, and gut transit time significantly decreased in a dose-dependent manner in rats fed FOS and the fecal concentration of bifidobacteria was higher in rats fed FOS than in control rats. The fecal output of total short-chain fatty acids, acetate, and propionate was significantly increased by the presence of FOS and was negatively correlated with the number of ACs, whereas the fecal output of butyrate showed no significant correlation with FOS dosage. The addition of soy isoflavone to the diet did not result in any significant differences in gut ecosystem parameters. Therefore, we conclude that the suppressive effect of soy isoflavone on ACs was not associated with the intestinal ecosystem, which was significantly altered by the dosage of FOS.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2285-2289
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• 2014

The solvolysis rate constants of 5-dimethylamino-naphthalene-1-sulfonyl chloride ($(CH_3)_2NC_{10}H_6SO_2Cl$, 1) in 31 different solvents are well correlated with the extended Grunwald-Winstein equation, using the $N_T$ solvent nucleophilicity scale and $Y_{Cl}$ solvent ionizing scale with sensitivity values of $0.96{\pm}0.09$ and $0.53{\pm}0.03$ for l and m, respectively; the correlation coefficient value was 0.955. These l and m values can be considered to support an $S_N2$ reaction pathway having a transition state (TS) structure similar to that of the benzenesulfonyl chloride reaction. This interpretation is further supported by the activation parameters, i.e., relatively small positive ${\Delta}H^{\neq}$ (12.0 to $15.9kcal{\cdot}mol^{-1}$) and large negative ${\Delta}S^{\neq}$ (-23.1 to $-36.3cal{\cdot}mol^{-1}{\cdot}K^{-1}$) values, and the solvent kinetic isotope effects (SKIEs, 1.34 to 1.88). Also, the selectivity values (S = 1.2 to 2.9) obtained in binary solvents are consistent with the proposed mechanism.