• Honam Mathematical Journal
• /
• v.24 no.1
• /
• pp.9-23
• /
• 2002

For a closed densely defined linear operator T on a Hilbert space H, let ${\prod}$ denote the function which corresponds to T, the orthogonal projection from $H{\oplus}H$ onto the graph of T. We extend some ordinary norm ineqralites comparing ${\parallel}{\Pi}(A)-{\Pi}(B){\parallel}$ and ${\parallel}A-B{\parallel}$ to the Schatten p-norm where A and B are bounded operators on H.

• East Asian mathematical journal
• /
• v.27 no.3
• /
• pp.299-308
• /
• 2011

The purpose of the present paper is to obtain some subordination and superordination preserving properties involving a certain family of multiplier transformations for meromorphic functions in the open unit disk. The sandwich-type theorems for these linear operators are also considered.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 1993.06a
• /
• pp.1098-1101
• /
• 1993

The purpose of this work is to build a fuzzy model of a batch culture for a process control. The process is highly nonlinear system with large delay. This paper presents two methods of modeling the process behavior. One is a method of recognizing them by fuzzy rules that are contracted by the pattern analysis in consideration of skilled operators' way. The other is a method of predicting them by approximate linear models and fuzzy rules by statistic analysis.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2785-2788
• /
• 2001

In this paper, we present a new interpolation scheme for image enhancement using fuzzy inference. In general, interpolation techniques are based on linear operators which are essentially lowpass filters, hence, they tend to blur fine details in the original image. In our approach, the operator itself balances the strength of its sharpening and noise suppressing components according to the properties of the input image data.

• The Pure and Applied Mathematics
• /
• v.15 no.3
• /
• pp.245-257
• /
• 2008

In this paper, we find the sufficient conditions of controllability of semi-linear neutral functional differential evolution equations with non local conditions using by fractional power of operators and Sadovskii's fixed point theorem.

• Korean Journal of Mathematics
• /
• v.28 no.4
• /
• pp.673-697
• /
• 2020

In this paper, we introduce and study the structured essential approximate and defect pseudospectrum of closed, densely defined linear operators in a Banach space. Beside that, we discuss some results of stability and some properties of these essential pseudospectra. Finally, we will apply the results described above to investigate the essential approximate and defect pseudospectra of the following integro-differential transport operator.

• Communications of the Korean Mathematical Society
• /
• v.37 no.2
• /
• pp.409-414
• /
• 2022

Let A ∈ B(X) be a spectral operator on a non-archimedean Banach space over an algebraically closed field. In this note, we give a necessary and sufficient condition on the resolvent of A so that the discrete semigroup consisting of powers of A is uniformly-bounded.

• Kyungpook Mathematical Journal
• /
• v.61 no.4
• /
• pp.845-858
• /
• 2021

We present new bounds for the numerical radius of bounded linear operators and 2 × 2 operator matrices. We apply upper bounds for the numerical radius to the Frobenius companion matrix of a complex monic polynomial to obtain new estimations for the zeros of that polynomial. We also show with numerical examples that our new estimations improve on the existing estimations.

• Bulletin of the Korean Mathematical Society
• /
• v.52 no.4
• /
• pp.1365-1373
• /
• 2015

We find all ${\mathcal{F}}{\mathcal{M}}_m$-natural operators A transforming torsion free classical linear connections ${\nabla}$ on m-manifolds M into base preserving fibred maps $A({\nabla}):{\bar{J}}^rY{\rightarrow}J^rY$ for ${\mathcal{F}}{\mathcal{M}}_m$-objects Y with bases M, where ${\bar{J}}^r$, $J^r$ are the semiholonomic and holonomic jet functors of order r on the category ${\mathcal{F}}{\mathcal{M}}_m$ of fibred manifolds with m-dimensional bases and their fibred maps with embeddings as base maps.

• Journal of applied mathematics & informatics
• /
• v.29 no.5_6
• /
• pp.1525-1532
• /
• 2011

The $m{\times}n$ Boolean matrix A is said to be of Boolean rank r if there exist $m{\times}r$ Boolean matrix B and $r{\times}n$ Boolean matrix C such that A = BC and r is the smallest positive integer that such a factorization exists. We consider the the sets of matrix ordered pairs which satisfy extremal properties with respect to Boolean rank inequalities of matrices over nonbinary Boolean algebra. We characterize linear operators that preserve these sets of matrix ordered pairs as the form of $T(X)=PXP^T$ with some permutation matrix P.