• Journal of Ginseng Research
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• 제44권2호
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• pp.308-311
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• 2020

Extracts of ginseng species show antihyperglycemic activity. We evaluated the inhibitory effects of diabetic complications for Korean Red Ginseng (KRG), which is enriched in ginsenosides using Otsuka Long-Evans Tokushima Fatty (OLETF) rats. The animals were divided into one of four groups (n = 6~9): Long-Evans-Tokushima-Otsuka rats (control rats), OLETF rats, rats given 200 mg/kg KRG, and rats given 400 mg/kg KRG. We examined the protective potential of KRG against type 2 diabetic illnesses. The results exhibited that KRG showed significant antihyperglycemic and antioxidative effects in KRG-treated OLETF rats. And, our results proposed the amelioration of cardiac function through normalized ejection fraction, fractional shortening, and vascular reactivity. Furthermore, histopathological abnormalities in the OLETF rats were prevented by KRG treatment.

• 대한수학회논문집
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• 제10권1호
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• pp.49-55
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• 1995

This paper is the third of a series in which smoothness properties of function in several variables are discussed. The germ of the whole theory was laid in the works by Folland and Stein [4]. On nilpotent Lie groups, they difined analogues of the classical $L^p$ Sobolev or potential spaces in terms of fractional powers of sub-Laplacian, L and extended several basic theorems from the Euclidean theory of differentaiability to these spaces: interpolation properties, boundedness of singular integrals,..., and imbeding theorems. In this paper we study the analogue to the extension theorem for the Folland-Stein spaces. The analogue to Stein's restriction theorem were studied by M. Mekias [5] and Y.M. Kim [6]. First, we have the space of Bessel potentials on the Heisenberg group introduced by Folland [4].

• 대한수학회보
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• 제43권3호
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• pp.589-598
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• 2006

In the present investigation, sharp upper bounds of $|a3-{\mu}a^2_2|$ for functions $f(z)=z+a_2z^2+a_3z^3+...$ belonging to certain subclasses of starlike and convex functions with respect to symmetric points are obtained. Also certain applications of the main results for subclasses of functions defined by convolution with a normalized analytic function are given. In particular, Fekete-Szego inequalities for certain classes of functions defined through fractional derivatives are obtained.

• 천문학회지
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• 제49권1호
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• pp.9-18
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• 2016

Euclid, which is primarily a dark-energy/cosmology mission, may have a microlensing component, consisting of perhaps four dedicated one-month campaigns aimed at the Galactic bulge. We show that such a program would yield excellent auxilliary science, including asteroseismology detections for about 100 000 giant stars, and detection of about 1000 Kuiper Belt Objects (KBOs), down to 2-2.5 mag below the observed break in the KBO luminosity function at I ∼ 26. For the 400 KBOs below the break, Euclid will measure accurate orbits, with fractional period errors ≲ 2.5%.

• 천문학회지
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• 제47권6호
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• pp.279-291
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• 2014

I show that the WFIRST microlensing survey will enable detection and precision orbit determination of Kuiper Belt Objects (KBOs) down to $H_{vega}=28.2$ over an effective area of ${\sim}17deg^2$. Typical fractional period errors will be ${\sim}1.5%{\times}10^{0.4(H-28.2)}$ with similar errors in other parameters for roughly 5000 KBOs. Binary companions to detected KBOs can be detected to even fainter limits, $H_{vega}=29$, corresponding to R~30.5 and effective diameters D~7 km. For KBOs H~23, binary companions can be found with separations down to 10 mas. This will provide an unprecedented probe of orbital resonance and KBO mass measurements. More than a thousand stellar occultations by KBOs can be combined to determine the mean size as a function of KBO magnitude down to H~25. Current ground-based microlensing surveys can make a significant start on finding and characterizing KBOs using existing and soon-to-be-acquired data.

• Journal of Mechanical Science and Technology
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• 제16권5호
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• pp.720-731
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• 2002

Flow with moving free surfaces is analyzed with an the Eulerian coordinate system. This study proposes a semi-implicit filling algorithm using VOF in which the PLIC (Piecewise Linear Interface Calculation) -type interface reconstruction method and the donor-acceptor-type front advancing scheme are adopted. Also, a new scheme using extrapolation of the stream function is proposed to find the velocity of the node that newly enters the computational domain. The effect of wall boundary conditions on the flow field and temperature field is examined by numerically solving a two-dimensional casting process.

• 제어로봇시스템학회논문지
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• 제4권5호
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• pp.574-578
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• 1998

This paper considers the robust positive real problem for linear systems with linear fractional-type norm-bounded repeated scalar block parameter uncertainty. It is shown that the robust positive real problem can be converted into the standard positive real problem without uncertainty that can be used for the analysis of the given uncertain linear system and the synthesis of a controller that robustly stabilizes and achieves the extended strict positive realness property of the closed-loop transfer function. These results can be also applied to the linear system with general structured uncertainty containing repeated scalar block parameters and are extensions of the previous works that consider only norm-boundedness of the affine unstructured uncertainty.

• 동력기계공학회지
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• 제5권4호
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• pp.44-52
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• 2001

This paper considers a modeling and identification for the MIMO magnetic bearing system. To obtain the nominal plant transfer functions, we have experimented on the frequency response by a closed-loop identification method because the system is unstable essentially. We suggest a method of curve-fitting for obtaining the transfer function from the frequency responses by using the system's modeling structure and two controllers which are different from each other. From the frequency response results, we found the effects of coupling by opposing controllers. And using this effects and the system's modeling structure, we could obtain the transfer functions of which have the same modularized denominators.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.108-110
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• 2006

A prediction model of charge concentration of silicon nitride (SiN) thin films was constructed by using neural network and genetic algorithm. SIN films were deposited by plasma enhanced chemical vapor deposition and the deposition process was characterized by means of $2^{6-1}$ fractional factorial experiment. Effect of five training factors on the model prediction performance was optimized by using genetic algorithm. This was examined as a function of the learring rate. The root mean squared error of optimized model was 0.975, which is much smaller than statistical regression model by about 45%. The constructed model can facilitate a Qualitative analysis of parameter effects on the charge concentration.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.634-637
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• 2008

A large eddy simulation with an explicit filter on unstructured mesh is presented. The flow filed is semi-implicitly marched by a fractional step method. Spatial discretization of the solver is designed to guarantee the second order accuracy. An isotropic explicit filter is adopted for measuring the level of subgrid scale velocity fluctuation. The filter is linearity-preserving and has second order commutation error. The developed subgrid scale model is basically eddy viscosity model which depends on the explicitly filtered fields and needs no additional ad hoc wall treatment, such as van Driest damping function. For the validation, the flows in a channel and a pipe are calculated and compared to experimental data and numerical results in the literature.