Results 31 to 40 of about 17,562 (171)

A Deep Learning Framework for Forecasting Medium‐Term Covariance in Multiasset Portfolios

open access: yesJournal of Forecasting, EarlyView.
ABSTRACT Forecasting the covariance matrix of asset returns is central to portfolio construction, risk management, and asset pricing. However, most existing models struggle at medium‐term horizons, several weeks to months, where shifting market regimes and slower dynamics prevail.
Pedro Reis, Ana Paula Serra, João Gama
wiley   +1 more source

A Generalization of Quasi-Frobenius Rings [PDF]

open access: yesProceedings of the American Mathematical Society, 1969
Let \(R\) be a ring and \(_R\mathcal M\) the category of all left \(R\)-modules. \textit{G. Azumaya} [Nagoya Math. J. 27, 697--708 (1966; Zbl 0144.02303)] proved that if all faithful left \(R\)-modules are generators in \(_R\mathcal M\), \(R\) is left self-injective and a direct sum of indecomposable left ideals having minimal left ideals (cf.
openaire   +2 more sources

Frozen Differential Scattering in Reconfigurable Complex Media

open access: yesLaser &Photonics Reviews, EarlyView.
A localized perturbation universally results in a rank‐one update of the scattering matrix of any complex medium. The resulting differential output wavefront is “frozen”: its spatial pattern is fixed (agnostic to the input wavefront). Experiments with a programmable‐metasurface‐parametrized wireless link validate frozen differential scattering and ...
Philipp del Hougne
wiley   +1 more source

MacWilliams' Extension Theorem for Bi-Invariant Weights over Finite Principal Ideal Rings [PDF]

open access: yes, 2013
A finite ring R and a weight w on R satisfy the Extension Property if every R-linear w-isometry between two R-linear codes in R^n extends to a monomial transformation of R^n that preserves w.
Fadden, Cathy Mc   +4 more
core  

Offline Reconstruction of Diffusion MRI Acquisitions for Comparison Between Complex PCA‐Based and AI‐Based Denoising

open access: yesMagnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose Optimal diffusion MRI (dMRI) data for image denoising is often unavailable from scanner reconstruction. In this work, we make available an offline reconstruction pipeline for GE dMRI acquisitions, giving access to complex dMRI data. Furthermore, we compare the efficacy of GE HealthCare's AIR‐Recon DL (ARDL), a proprietary convolutional
Francesco D'Antonio   +4 more
wiley   +1 more source

Stabilizer codes over Frobenius rings [PDF]

open access: yes2012 IEEE International Symposium on Information Theory Proceedings, 2012
Quantum error-correcting codes over finite fields have been widely studied, but quantum codes over rings have been left largely unexplored. This paper introduces stabilizer codes over finite Frobenius rings and establishes their connection to classical code. Structural properties of stabilizer codes over finite Frobenius rings are established.
Sushma Nadella, Andreas Klappenecker
openaire   +1 more source

Optimizing Selective RF Pulses for Enhanced Signal Stability in Turbo Spin Echo Using a Differentiable Extended Phase Graph Model

open access: yesMagnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To improve slice profile consistency across echo trains in turbo spin echo (TSE) imaging, thereby reducing image blurring and increasing the accuracy of multi echo spin echo T2$$ {T}_2 $$ mapping. Methods Excitation and refocusing RF pulses were optimized for TSE using a differentiable extended phase graph model that incorporates the ...
Madison M. Augelli   +3 more
wiley   +1 more source

Some results on quasi-Frobenius rings [PDF]

open access: yesCommentationes Mathematicae Universitatis Carolinae, 2017
Summary: We give some new characterizations of quasi-Frobenius rings by the generalized injectivity of rings. Some characterizations give affirmative answers to some open questions about quasi-Frobenius rings, and some characterizations improve some results on quasi-Frobenius rings.
openaire   +2 more sources

Ellipsoid‐Based Interval‐Type Uncertainty Model Updating Based on Riemannian Manifold and Gaussian Process Model

open access: yesInternational Journal of Mechanical System Dynamics, EarlyView.
ABSTRACT Modern engineering systems require advanced uncertainty‐aware model updating methods that address parameter correlations beyond conventional interval analysis. This paper proposes a novel framework integrating Riemannian manifold theory with Gaussian Process Regression (GPR) for systems governed by Symmetric Positive‐Definite (SPD) matrix ...
Yanhe Tao   +3 more
wiley   +1 more source

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