نتایج جستجو برای: singular di erential operator

تعداد نتایج: 399959  

1991
Percy Deift James Demmel Carlos Tomei

We consider computing the singular value decomposition of a bidiagonal matrix B. This problem arises in the singular value decomposition of a general matrix, and in the eigenproblem for a symmetric positive de nite tridiagonal matrix. We show that if the entries of B are known with high relative accuracy, the singular values and singular vectors of B will be determined to much higher accuracy t...

1995
Paul M. Furth Andreas G. Andreou

Three schemes for linearizing the transconductance of the basic di erential pair in subthreshold CMOS are examined: 1) multiple asymmetric di erential pairs, 2) source degeneration via symmetric di usors, and 3) source degeneration via a single di usor. Using a maximally at optimizing criterion, the linear range of the basic di erential pair can be increased by four-to-eight times.

1998
V. LYUBASHENKO A. SUDBERY

We introduce and study the Koszul complex for a Hecke R-matrix. Its cohomologies, called the Berezinian, are used to de ne quantum superdeterminant for a Hecke R-matrix. Their behaviour with respect to Hecke sum of R-matrices is studied. Given a Hecke R-matrix in n-dimensional vector space, we construct a Hecke R-matrix in 2n-dimensional vector space commuting with a di erential. The notion of ...

1991
Xuejia Lai James L. Massey Sean Murphy

This paper considers the security of iterated block ciphers against the di erential cryptanalysis introduced by Biham and Shamir Di erential cryptanalysis is a chosen plaintext attack on secret key block ciphers that are based on iterating a cryptographically weak function r times e g the round Data Encryption Standard DES It is shown that the success of such attacks on an r round cipher depend...

Journal: :Automatica 2002
Emilia Fridman

A small delay in the feedback loop of a singularly perturbed system may destabilize it; however, without the delay, it is stable for all small enough values of a singular perturbation parameter . Su3cient and necessary conditions for preserving stability, for all small enough values of delay and , are obtained in two cases: in the case of delay proportional to and in the case of independent del...

1991
Xuejia Lai James L. Massey Sean Murphy

This paper considers the security of iterated block ciphers against the di erential cryptanalysis introduced by Biham and Shamir. Di erential cryptanalysis is a chosen-plaintext attack on secret-key block ciphers that are based on iterating a cryptographically weak function r times (e.g., the 16-round Data Encryption Standard (DES) ). It is shown that the success of such attacks on an r-round c...

1997
John Mallet-Paret

We obtain existence of traveling wave solutions for a class of spatially discrete systems, namely lattice di erential equations. Uniqueness of the wave speed c, and uniqueness of the solution with c 6= 0, are also shown. More generally, the global structure of the set of all traveling wave solutions is shown to be a smooth manifold where c 6= 0. Convergence results for solutions are obtained at...

2004
Hitoshi Ishiia

We establish comparison and existence theorems of viscosity solutions of the initial-boundary value problem for some singular degenerate parabolic partial di/erential equations with nonlinear oblique derivative boundary conditions. The theorems cover the capillary problem for the mean curvature 1ow equation and apply to more general Neumann-type boundary problems for parabolic equations in the ...

1999
Sönke Frantz Karl Rohr H. Siegfried Stiehl

Manually extracting 3D anatomical point landmarks from tomographic images is generally tedious and time-consuming. A semiautomatic procedure for landmark extraction, which allows for interactive control, o ers the possibility to improve on this. The detection performance is decisive for the applicability of such a procedure. However, existing computational approaches to landmark detection often...

1999
Benjamin Jun

Cryptosystem designers frequently assume that secrets will be manipulated in closed, reliable computing environments. Unfortunately, actual computers and microchips leak information about the operations they process. This paper examines speci c methods for analyzing power consumption measurements to nd secret keys from tamper resistant devices. We also discuss approaches for building cryptosyst...

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