Results 61 to 70 of about 41,020 (249)
A new look at nonnegativity on closed sets and polynomial optimization [PDF]
, 2011 We first show that a continuous function f is nonnegative on a closed set $K\subseteq R^n$ if and only if (countably many) moment matrices of some signed measure $d\nu =fd\mu$ with support equal to K, are all positive semidefinite (if $K$ is compact $\mu$
Lasserre, Jean B.
core +3 more sources
Fractional Hadamard powers of positive semidefinite matrices
Linear Algebra and its Applications, 2003 AbstractWe consider the class Sn of all real positive semidefinite n×n matrices, and the subclass Sn+ of all A∈Sn with non-negative entries. For a positive, non-integer number α and some A∈Sn+, when will the fractional Hadamard power A♢α again belong to Sn+? It is known that, for a specific α, this holds for all A∈Sn+ if and only if α>n−2. Now let A∈Sn+
J.D. Stegeman, Pal Fischer
openaire +3 more sources
Can ensemble‐based parameter estimation aid parameterization design?
Quarterly Journal of the Royal Meteorological Society, EarlyView.Parameterization schemes rely on uncertain empirical parameters, the values of which can be estimated objectively and iteratively with ensemble data assimilation methods. Since all sources of forecast error in the background ensemble project onto parameter adjustments, the estimated parameters may converge to implausible values or not converge at all ...
Stefano Serafin, Martin Weissmann
wiley +1 more source
Advanced Quantum Technologies, EarlyView.The hybrid approach to Quantum Supervised Machine Learning is compatible with Noisy Intermediate Scale Quantum (NISQ) devices but hardly useful. Pure quantum kernels requiring fault‐tolerant quantum computers are more promising. Examples are kernels computed by means of the Quantum Fourier Transform (QFT) and kernels defined via the calculation of ...
Massimiliano Incudini +2 more
wiley +1 more source
A Physics‐Informed Learning Framework to Solve the Infinite‐Horizon Optimal Control Problem
International Journal of Robust and Nonlinear Control, EarlyView.ABSTRACT We propose a physics‐informed neural networks (PINNs) framework to solve the infinite‐horizon optimal control problem of nonlinear systems. In particular, since PINNs are generally able to solve a class of partial differential equations (PDEs), they can be employed to learn the value function of the infinite‐horizon optimal control problem via
Filippos Fotiadis +1 more
wiley +1 more source
Generalized Randić Estrada Indices of Graphs
Mathematics, 2022 Let G be a simple undirected graph on n vertices. V. Nikiforov studied hybrids of AG and DG and defined the matrix AαG for every real α∈[0,1] as AαG=αDG+(1−α)AG.
Eber Lenes +3 more
doaj +1 more source
The role of identification in data‐driven policy iteration: A system theoretic study
International Journal of Robust and Nonlinear Control, EarlyView.Abstract The goal of this article is to study fundamental mechanisms behind so‐called indirect and direct data‐driven control for unknown systems. Specifically, we consider policy iteration applied to the linear quadratic regulator problem. Two iterative procedures, where data collected from the system are repeatedly used to compute new estimates of ...
Bowen Song, Andrea Iannelli
wiley +1 more source
Support-based lower bounds for the positive semidefinite rank of a nonnegative matrix [PDF]
, 2013 The positive semidefinite rank of a nonnegative $(m\times n)$-matrix~$S$ is the minimum number~$q$ such that there exist positive semidefinite $(q\times q)$-matrices $A_1,\dots,A_m$, $B_1,\dots,B_n$ such that $S(k,\ell) = \mbox{tr}(A_k^* B_\ell)$.
Dirk, Oliver Theis, Troy Lee
core
Generic Spectrahedral Shadows [PDF]
, 2015 Spectrahedral shadows are projections of linear sections of the cone of positive semidefinite matrices. We characterize the polynomials that vanish on the boundaries of these convex sets when both the section and the projection are generic.Comment ...
Sinn, Rainer, Sturmfels, Bernd
core +1 more source
Functions that preserve families of positive semidefinite matrices
Linear Algebra and its Applications, 1995 AbstractWe study various notions of multivariate functions which map families of positive semidefinite matrices or of conditionally positive semidefinite matrices into matrices of the same type.
Charles A. Micchelli +2 more
openaire +2 more sources