Results 51 to 60 of about 71,699 (272)
Fractional Hadamard powers of positive semidefinite matrices
Linear Algebra and its Applications, 2003 The authors consider the class \(\varphi_n\) of all real positive semidefinite \(n\times n\) matrices, and the subclass \(\varphi^+_n\) of all \(A\in\varphi_n\) with non-negative entries. For a positive, non-integer number \(\alpha\) and some \(A\in \varphi_n^+\), when will the fractional Hadamard power \(A^{\diamondsuit \alpha}\) again belong to ...
Fischer, P., Stegeman, J.D.
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International Journal of Adaptive Control and Signal Processing, EarlyView.This paper proposes two projector‐based Hopfield neural network (HNN) estimators for online, constrained parameter estimation under time‐varying data, additive disturbances, and slowly drifting physical parameters. The first is a constraint‐aware HNN that enforces linear equalities and inequalities (via slack neurons) and continuously tracks the ...
Miguel Pedro Silva
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Conditions for Existence of Dual Certificates in Rank-One Semidefinite Problems [PDF]
, 2014 Several signal recovery tasks can be relaxed into semidefinite programs with rank-one minimizers. A common technique for proving these programs succeed is to construct a dual certificate.
Hand, Paul
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The positive semidefiniteness of partitioned matrices
Linear Algebra and its Applications, 1988 The author gives the character of the Löwner order, i.e. for symmetric matrices A and C such that \(C\leq A\), a symmetric matrix B satisfies \(C\leq B\leq A\) if and only if \(tr(R'B)\leq 1/2tr\{R'(A+C)\}+1/4tr(Q_ R)\) for all possible R, where \(Q_ R=\{(A-C)^{1/2}(R+R')(A-C)(R+R')(A- C)^{1/2}\}^{1/2}.\) An application to varieties of problems ...
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Matrices with high completely positive semidefinite rank
Linear Algebra and its Applications, 2017 A real symmetric matrix $M$ is completely positive semidefinite if it admits a Gram representation by (Hermitian) positive semidefinite matrices of any size $d$. The smallest such $d$ is called the (complex) completely positive semidefinite rank of $M$, and it is an open question whether there exists an upper bound on this number as a function of the ...
de Laat, David +2 more
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Experimental Joint Estimation of Phase and Phase Diffusion Via Deterministic Bell Measurements
Advanced Science, EarlyView.This work employs Bell measurement, a form of entangling measurement, to estimate both the phase and its fluctuations in an optical interferometer. By incorporating a novel quantum effect at the measurement stage, the proposed method achieves the ultimate precision limit and demonstrates the significant potential of entangling measurements in multi ...
Ben Wang +4 more
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GBD and $ \mathcal{L} $-positive semidefinite elements in $ C^* $-algebras
AIMS MathematicsThis paper focused on the generalized Bott-Duffin (GBD) inverse and the $ {\rm GBD} $ elements in Banach algebra with involution and $ C^* $-algebra, as well as on the property of the $ p $-positive semidefinite elements that are a generalization of the $
Kezheng Zuo +2 more
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Using distance on the Riemannian manifold to compare representations in brain and in models
NeuroImage, 2021 Representational similarity analysis (RSA) summarizes activity patterns for a set of experimental conditions into a matrix composed of pairwise comparisons between activity patterns.
Mahdiyar Shahbazi +3 more
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Trace-Inequalities and Matrix-Convex Functions
Fixed Point Theory and Applications, 2010 A real-valued continuous function f(t) on an interval (α,β) gives rise to a map X↦f(X) via functional calculus from the convex set of n×n Hermitian matrices all of whose eigenvalues belong to the interval. Since the subpace of
Tsuyoshi Ando
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A Unique "Nonnegative" Solution to an Underdetermined System: from Vectors to Matrices [PDF]
, 2009 This paper investigates the uniqueness of a nonnegative vector solution and the uniqueness of a positive semidefinite matrix solution to underdetermined linear systems.
Ao Tang +3 more
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