• Journal of the Chungcheong Mathematical Society
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• v.4 no.1
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• pp.11-38
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• 1991

Let $E_n$ be the real ordered space of all $n{\times}n$ Hermitian Matrices and let T be a positive linear operator from $E_2$ to $E_3$. We prove in this paper that T is extreme if and only if T is unitarily equivalent to a map of the form $S_z$ for some $z{\in}C^2$ where $S_z$ is defined by $S_z(xx^*)=ww^*$, $w_i=x_iz_i$ for i = 1, 2 and $w_3=0$.

• Journal of applied mathematics & informatics
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• v.9 no.2
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• pp.531-542
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• 2002

In this paper we deal with a sequence of positive linear operators ${{R_n}}^{[$\beta$]}$ approximating functions on the unbounded interval [0, $\infty$] which were firstly used by K. balazs and J. Szabados. We give pointwise estimates in the framework of polynomial weighted function spaces. Also we establish a Voronovskaja type theorem in the same weighted spaces for ${{K_n}}^{[$\beta$]}$ operators, representing the integral generalization in Kantorovich sense of the ${{R_n}}^{[$\beta$]}$.

• Bulletin of the Korean Mathematical Society
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• v.25 no.2
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• pp.171-174
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• 1988

Let M be an n-dimensional compact connected and oriented Riemannian manifold isometrically immersed in an (n+2)-dimensional Euclidean space $R^{n+2}$. Moore [5] proved that if M is of positive curvature, then M is a homotopy sphere. This result is generalized by Baldin and Mercuri [2], Baik and Shin [1] to the case of non-negative curvature, which is stated as follows: If M of non-negative curvature, then M is either a homotopy sphere or diffeomorphic to a product of two spheres. In particular, if there is a point at which the curvature operator is positive, then M is homeomorphic to a sphere.e.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.897-900
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• 2001

Space charge distributions in silane crosslinked polyethylene (SXLPE)/ crosslinked polyethylene (XLPE) laminates was investigated using a pulsed electroacoustic (PEA) method. XLPE shows heterocharge while SXLPE shows homocharge. Positive charge is accumulated at the interface of SXLPE/XLPE laminate when applied electric field is more than 20 kV/mm. The charge profile at various temperatures was also acquired using temperature-controllable PEA system. Although applied electric field is only 8.6 kV/mm, positive interfacial charge starts to appear near 50$^{\circ}C$.

• The Pure and Applied Mathematics
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• v.7 no.1
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• pp.1-6
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• 2000

An extension of $H\"{o}lder's$ inequality whose discrete form is described as follows is given. Let $\nu$ be a positive measure on a space Y, $\nu(Y)\;\neq\;0$, and let $f_{j}$(j = 1,2,...,n) be positive ν-integrable functions on Y. If ${\alpha}_j$ > 0(j = 1,2,...,n) and ${\beta}_j$(j = 1,2,...,k < n) are related to be (equation omitted) then (equation omitted).

• East Asian mathematical journal
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• v.32 no.1
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• pp.93-100
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• 2016

The generalized Gaussian image of a spacelike surface in $L^n$ lies in the indefinite positive quadric ${\mathbb{Q}}_+^{n-2}$ in the open submanifold ${\mathbb{C}}P_+^{n-1}$ of the complex projective space ${\mathbb{C}}P^{n-1}$. The purpose of this paper is to find out detailed information about ${\mathbb{Q}}_+^{n-2}{\subset}{\mathbb{C}}P_+^{n-1}$.

• Bulletin of the Korean Chemical Society
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• v.10 no.5
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• pp.452-458
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• 1989

The static and dynamic phenomena of a model for the metabolic control system with positive feedback are discussed with the static and dynamic renormalization group theory. Then, the explicit results for the static and dynamic exponents are obtained up to the second order of ${\varepsilon}$-expansion, ${\varepsilon}$ being 4-d, where d is the space dimensionality of the system.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.36-36
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• 2004

Ionospheric data from DGS-256 ionosonde operated by Radio Research Laboratory in Anyang archived during 1991-2002 was extracted and analyzed firstly in Korea. Daily, monthly and annual variations of the 12-year F2 layer critical frequency(foF2) are derived to investigate the statistical ionospheric characteristics during one complete solar cycle. Positive correlation between the mean values of 24-hourly monthly median foF2 and the monthly smoothed sunspot number(SSN) for the same period is found. (omitted)

• Journal of Astronomy and Space Sciences
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• v.11 no.2
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• pp.196-207
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• 1994

Data on 27 W UMa systems having a asymmetric light curve so called O'Conell effect have been collected. Investigated 27 W UMa systems were classified into 12 positive and 15 negative type according to the shape of its asymmetric light curve. A list of members of the group, their current observational statue, and their physical and evolutional relationship to asymmetric W UMa type binaries are discussed.

• Bulletin of the Korean Mathematical Society
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• v.52 no.5
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• pp.1649-1660
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• 2015

In this paper, we completely characterize the nontrivial reducing subspaces of the Toeplitz operator $T{_{z{^N_1{\bar{z}}^M_2}}$ on the Bergman space $A^2(\mathbb{D}^2)$, where N and M are positive integers.