Yoo Young Koo
Yonsei University
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Featured researches published by Yoo Young Koo.
Numerical Functional Analysis and Optimization | 2013
Hyoung Seok Kim; Yoo Young Koo; Jae Kun Lim
Two parameterizations of oblique duals of a given frame sequence are applied to show that the sum of a frame sequence and one of its oblique duals may not be a frame sequence, and that type II dual is locally (and globally) optimal in some sense and that the excesses of the frame sequence and its oblique duals are the same. Other observations on the duals of a frame sequence are included also.
Linear & Multilinear Algebra | 2013
Yoo Young Koo; Jae Kun Lim
Casazza, Han and Larson characterized various properties of the direct sum of two frame sequences. We add characterizations of other properties and study the relationship between the direct sum and the sum of frame sequences. In particular, we find a necessary and sufficient condition for the sum of two strongly disjoint (orthogonal) frame sequences (in the same Hilbert space) to be a frame sequence, and thereby show that the sum of two strongly disjoint frame sequences may not be a frame sequence. We also show that the closedness of the sum of the synthesis operators of two frame sequences and that of the sum of the frame operators of the same frame sequences are not related. Other observations are also included.
Quaestiones Mathematicae | 2011
Yoo Young Koo; Jae Kun Lim
By extending the works of Arias et al. and Balazs we present a natural sufficient condition via frames for the membership of the Schatten p-class operators for 1 ≤ p ≤ 2, and show that such a condition is not sufficient to guarantee the membership of the Schatten-class operators for p > 2.By extending the works of Arias et al. and Balazs we present a natural sufficient condition via frames for the membership of the Schatten p-class operators for 1 ≤ p ≤ 2, and show that such a condition is not sufficient to guarantee the membership of the Schatten-class operators for p > 2. Quaestiones Mathematicae 34(2011), 203–211.
Proceedings of SPIE | 2009
Shannon Bishop; Christopher Heil; Yoo Young Koo; Jae Kun Lim
This paper surveys recent results on frame sequences. The first group of results characterizes the relationships that hold among various types of dual frame sequences. The second group of results characterizes the relationships that hold among the major Paley-Wiener perturbation theorems for frame sequences, and some of the properties that remain invariant under such perturbations.
Linear & Multilinear Algebra | 2008
Yoo Young Koo; Jae Kun Lim; In-Sook Shin
We first characterize finite frames and orthogonal frames generated by normal operators on , and apply the results to (orthogonal) generalized harmonic frames. We also show that the canonical dual frame of a finite frame generated by a normal operator on is always generated by a (not-necessarily normal) operator, and give a condition when a finite frame generated by a normal operator has an alternate dual frame generated by a normal operator.
Acta Applicandae Mathematicae | 2009
Christopher Heil; Yoo Young Koo; Jae Kun Lim
Linear Algebra and its Applications | 2007
Yoo Young Koo; Jae Kun Lim
Linear Algebra and its Applications | 2010
Shannon Bishop; Christopher Heil; Yoo Young Koo; Jae Kun Lim
Bulletin of the Malaysian Mathematical Sciences Society | 2018
Yoo Young Koo; Jae Kun Lim
Electronic Journal of Linear Algebra | 2015
Yoo Young Koo; Jae Kun Lim