Results 51 to 60 of about 2,871 (211)

Theory of Supercritical Coupling and Generalized Bound States in the Continuum

open access: yesLaser &Photonics Reviews, EarlyView.
We develop a general theory of supercritical coupling and generalized bound states in the continuum (gBICs), revealing how interference between radiative and absorptive channels enables quality factors beyond conventional material‐loss limits. The framework unifies non‐Hermitian mode coupling, causality‐driven reactive interactions, and interference ...
Sergio Balestrieri   +3 more
wiley   +1 more source

Generalized Randić Estrada Indices of Graphs

open access: yesMathematics, 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

Finite‐Time Disturbance Observer‐Based Nonlinear Robust Adaptive Control of Hydraulic Manipulator With Parameter Identification

open access: yesInternational Journal of Mechanical System Dynamics, EarlyView.
ABSTRACT Hydraulic manipulators exhibit strong coupling, pronounced nonlinearities, and significant modeling uncertainties, which hinder high‐precision motion control. This paper proposes a finite‐time disturbance observer–based nonlinear robust adaptive control (RAC‐FTDO) framework enhanced by a physically consistent dynamic parameter identification ...
Tianyu Gao   +3 more
wiley   +1 more source

Adaptation of Symmetric Positive Semi-Definite Matrices for the Analysis of Textured Images

open access: yesCybernetics and Information Technologies, 2018
This paper addresses the analysis of textured images using the symmetric positive semi-definite matrix. In particular, a field of symmetric positive semi-definite matrices is used to estimate the structural information represented by the local ...
Akl Adib
doaj   +1 more source

Anisotropic Initial Damage and Its Effect on Tensile Response of Plain Concrete

open access: yesInternational Journal for Numerical and Analytical Methods in Geomechanics, EarlyView.
ABSTRACT Damage is often described as isotropic, implying that a scalar value describes its initial state. However, the prior micro‐cracking pattern at points of an existing building, that is, the initial damage, may be oriented by a preload. The degradation of the Volume Element due to oriented preloads shall be described as anisotropic and ...
A. Fau   +3 more
wiley   +1 more source

Generalizing the Gaussian Network Model: Spanning‐Tree Thermodynamics Shows Entropy‐Driven KRAS Activation

open access: yesProteins: Structure, Function, and Bioinformatics, EarlyView.
ABSTRACT The GTPase KRAS executes a conformational switch between a GTP‐bound active state and a GDP‐bound inactive state, a process central to oncogenic signaling. However, the structural basis of this switching at the level of residue‐contact organization remains incompletely characterized by traditional binary structural models.
Fatma Senguler Ciftci, Burak Erman
wiley   +1 more source

Functions that preserve families of positive semidefinite matrices

open access: yes, 1995
We study various notions of multivariate functions which map families of positive semidefinite matrices or of conditionally positive semidefinite matrices into matrices of the same ...
Pinkus, Allan   +2 more
core   +1 more source

Control Systems Design With Enlarged Stability Domains for Nonlinear Constrained Systems via Sum‐of‐Squares Optimization

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT Designing safe control laws for nonlinear systems is challenging, especially when ensuring stability under actuator saturation and state constraints. A key aspect is embedding controllers with a Region of Attraction (ROA), which defines initial conditions guaranteeing convergence to a stable equilibrium point (EP).
Bhaskar Biswas   +3 more
wiley   +1 more source

Separability of symmetric states and vandermonde decomposition

open access: yesNew Journal of Physics, 2020
Symmetry is one of the central mysteries of quantum mechanics and plays an essential role in multipartite entanglement. In this paper, we consider the separability problem of quantum states in the symmetric space.
Lilong Qian, Lin Chen, Delin Chu
doaj   +1 more source

Fractional Hadamard powers of positive semidefinite matrices

open access: yesLinear 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.
openaire   +3 more sources

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