• 제목/요약/키워드: skew

검색결과 711건 처리시간 0.402초

SKEW COMPLEX SYMMETRIC OPERATORS AND WEYL TYPE THEOREMS

  • KO, EUNGIL;KO, EUNJEONG;LEE, JI EUN
    • Bulletin of the Korean Mathematical Society
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    • 제52권4호
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    • pp.1269-1283
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    • 2015
  • An operator $T{{\in}}{\mathcal{L}}({\mathcal{H}})$ is said to be skew complex symmetric if there exists a conjugation C on ${\mathcal{H}}$ such that $T=-CT^*C$. In this paper, we study properties of skew complex symmetric operators including spectral connections, Fredholmness, and subspace-hypercyclicity between skew complex symmetric operators and their adjoints. Moreover, we consider Weyl type theorems and Browder type theorems for skew complex symmetric operators.

THE RIESZ DECOMPOSITION THEOREM FOR SKEW SYMMETRIC OPERATORS

  • Zhu, Sen;Zhao, Jiayin
    • Journal of the Korean Mathematical Society
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    • 제52권2호
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    • pp.403-416
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    • 2015
  • An operator T on a complex Hilbert space $\mathcal{H}$ is called skew symmetric if T can be represented as a skew symmetric matrix relative to some orthonormal basis for $\mathcal{H}$. In this note, we explore the structure of skew symmetric operators with disconnected spectra. Using the classical Riesz decomposition theorem, we give a decomposition of certain skew symmetric operators with disconnected spectra. Several corollaries and illustrating examples are provided.

Implementation of Automatic 4 Points OPU Skew Adjustment Device with Height Compensation (높이 보정이 가능한 자동4점 Optical PICK-UP Skew 조정장치 구현)

  • Oh, Dong-Kyu
    • Proceedings of the IEEK Conference
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    • 대한전자공학회 2008년도 하계종합학술대회
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    • pp.1095-1096
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    • 2008
  • By adding height compensation to the usual 3 points skew adjustment device, an improved functional skew adjustment device is implemented in this paper. The proposed skew adjustment device is for traverse which will be adapted to BD and HD player system requiring more accuracy. and It can adjust not only R/T skew but also height. The system is composed of personal computer, control box, kinematic mechanism device and bar-code reader device. Application programs are implemented by visual basic.

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SKEW BRACE ENHANCEMENTS AND VIRTUAL LINKS

  • Melody Chang;Sam Nelson
    • Communications of the Korean Mathematical Society
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    • 제39권1호
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    • pp.247-257
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    • 2024
  • We use the structure of skew braces to enhance the biquandle counting invariant for virtual knots and links for finite biquandles defined from skew braces. We introduce two new invariants: a single-variable polynomial using skew brace ideals and a two-variable polynomial using the skew brace group structures. We provide examples to show that the new invariants are not determined by the counting invariant and hence are proper enhancements.

ON ANNIHILATOR IDEALS OF A NEARRING OF SKEW POLYNOMIALS OVER A RING

  • Hashemi, Ebrahim
    • Journal of the Korean Mathematical Society
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    • 제44권6호
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    • pp.1267-1279
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    • 2007
  • For a ring endomorphism ${\alpha}$ and an ${\alpha}-derivation\;{\delta}$ of a ring R, we study relation between the set of annihilators in R and the set of annihilators in nearring $R[x;{\alpha},{\delta}]\;and\;R_0[[x;{\alpha}]]$. Also we extend results of Armendariz on the Baer and p.p. conditions in a polynomial ring to certain analogous annihilator conditions in a nearring of skew polynomials. These results are somewhat surprising since, in contrast to the skew polynomial ring and skew power series case, the nearring of skew polynomials and skew power series have substitution for its "multiplication" operation.

ON COMMUTATIVITY OF SKEW POLYNOMIALS AT ZERO

  • Jin, Hai-Lan;Kaynarca, Fatma;Kwak, Tai Keun;Lee, Yang
    • Bulletin of the Korean Mathematical Society
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    • 제54권1호
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    • pp.51-69
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    • 2017
  • We, in this paper, study the commutativity of skew polynomials at zero as a generalization of an ${\alpha}-rigid$ ring, introducing the concept of strongly skew reversibility. A ring R is be said to be strongly ${\alpha}-skew$ reversible if the skew polynomial ring $R[x;{\alpha}]$ is reversible. We examine some characterizations and extensions of strongly ${\alpha}-skew$ reversible rings in relation with several ring theoretic properties which have roles in ring theory.

Multivariate measures of skewness for the scale mixtures of skew-normal distributions

  • Kim, Hyoung-Moon;Zhao, Jun
    • Communications for Statistical Applications and Methods
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    • 제25권2호
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    • pp.109-130
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    • 2018
  • Several measures of multivariate skewness for scale mixtures of skew-normal distributions are derived. As a special case, those of multivariate skew-t distribution are considered in detail. Furthermore, the similarities, differences, and behavior of these measures are explored for cases of some specific members of the multivariate skew-normal and skew-t distributions using a simulation study. Since some measures are vectors, it is better to take all measures in the same scale when comparing them. In order to attain such a set of comparable indices, the sample version is considered for each of the skewness measures that are taken as test statistics for the hypothesis of t distribution against skew-t distribution. An application is reported for the data set consisting of 71 total glycerol and magnesium contents in Grignolino wine.

Free vibration of laminated composite skew plates with central cutouts

  • Lee, Sang-Youl;Park, Taehyo
    • Structural Engineering and Mechanics
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    • 제31권5호
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    • pp.587-603
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    • 2009
  • We performed a free vibration analysis of skew composite laminates with or without cutout based on the high-order shear deformation plate theory (HSDT). The effects of skew angles and ply orientations on the natural frequencies for various boundary conditions are studied using a nonlinear high-order finite element program developed for this study. The numerical results are in good agreement with those reported by other investigators for simple test cases, and the new results reported in this paper show the interactions between the skew angle, layup sequence and cutout size on the free vibration of the laminate. The findings highlight the importance of skew angles when analyzing laminated composite skew plates with cutout or without cutout.

Inter-Pin Skew Compensation Scheme for 3.2-Gb/s/pin Parallel Interface

  • Lee, Jang-Woo;Kim, Hong-Jung;Nam, Young-Jin;Yoo, Chang-Sik
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제10권1호
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    • pp.45-48
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    • 2010
  • An inter-pin skew compensation scheme is proposed, which minimizes the inter-pin skew of parallel interface induced by unequal trace length and loading of printed circuit board (PCB). The proposed scheme measures the inter-pin skew and compensates during power-up with simple hardware. The proposed scheme is applied to 3.2-Gb/s/pin DDR4 SDRAM and implemented in a 0.18 m CMOS process. The inter-pin skew is compensated in 324-cycles of 400-MHz clock and the skew is compensated to be less than 24-ps.