Results 51 to 60 of about 1,699 (225)

Dynamic survival risk prediction with time‐varying high‐dimensional images

Canadian Journal of Statistics, EarlyView.
Abstract Integrating longitudinal data with survival models is a prevalent strategy for dynamic survival risk prediction while accounting for subjects' longitudinally observed variables. However, existing methods primarily focus on scalar longitudinal data and seldom tackle the complexities associated with high‐dimensional longitudinal imaging data ...
Bingfan Liu, Haolun Shi, Shu Jiang, Liangliang Wang, Da Ma, Mirza Faisal Beg, Jiguo Cao, for the Alzheimer's Disease Neuroimaging Initiative   +7 more
wiley   +1 more source

Techniques to accelerate boundary element contributions in elasticity [PDF]

, 2007
The problem of rapid re-analysis of small problems in elasticity is investigated. The aim is to enable updated stress contours to be displayed in real-time as a design geometry is dynamically modified.
Scales, Derek
core  

Power spectral density and the brain

Canadian Journal of Statistics, EarlyView.
Abstract Time series from M/EEG (magneto/electroencephalography) and ECoG (electrocorticography) recordings are common sources of information about brain function. The power spectral density (PSD) preserves much of this information, up to second order. In the current decade, a burst of brain diagnostics using the slope of log(PSD) has appeared.
Priscilla E. Greenwood, Sveinung Erland, Lawrence M. Ward   +2 more
wiley   +1 more source

An analytical, phenomenological and numerical study of geophysical and magnetohydrodynamic turbulence in two dimensions [PDF]

, 2013
In this thesis I study a variety of two-dimensional turbulent systems using a mixed analytical, phenomenological and numerical approach. The systems under consideration are governed by the two-dimensional Navier-Stokes (2DNS), surface quasigeostrophic
Blackbourn, Luke A. K.
core  

Perturbation of eigenvalues due to gaps in 2-D boundaries [PDF]

, 2007
Motivated by problems involving diffusion through small gaps, we revisit two-dimensional eigenvalue problems with localized perturbations to Neumann boundary conditions.
Llewellyn Smith, Stefan G, Davis, Anthony M J   +1 more
core   +1 more source

Stability of Viscous Three‐Dimensional Stratified Couette Flow via Dispersion and Mixing

Communications on Pure and Applied Mathematics, EarlyView.
ABSTRACT This article explores the stability of stratified Couette flow in the viscous 3d$3d$ Boussinesq equations. In this system, mixing effects arise from the shearing background, and gravity acts as a restoring force leading to dispersive internal gravity waves.
Michele Coti Zelati, Augusto Del Zotto, Klaus Widmayer   +2 more
wiley   +1 more source

Stochastic Gradient Descent in High Dimensions for Multi‐Spiked Tensor PCA

Communications on Pure and Applied Mathematics, EarlyView.
ABSTRACT We study the high‐dimensional dynamics of online stochastic gradient descent (SGD) for the multi‐spiked tensor model. This multi‐index model arises from the tensor principal component analysis (PCA) problem with multiple spikes, where the goal is to estimate the unknown signal vectors within the N$N$‐dimensional unit sphere through maximum ...
Gérard Ben Arous, Cédric Gerbelot, Vanessa Piccolo   +2 more
wiley   +1 more source

Lie Symmetry Methods for Multidimensional Linear, Parabolic PDES and Diffusions [PDF]

In this paper we introduce methods based upon Lie symmetry analysis for the construction of explicit fundamental solutions of multidimensional parabolic PDEs.
Mark Craddock, Kelly A. Lennox
core  

Stability Bounds for the Generalized Kadanoff‐Baym Ansatz in the Holstein Dimer

Contributions to Plasma Physics, EarlyView.
ABSTRACT Predicting real‐time dynamics in correlated systems is demanding: exact two‐time Green's function methods are accurate but often too costly, while the Generalized Kadanoff‐Baym Ansatz (GKBA) offers time‐linear propagation at the risk of uncontrolled behavior. We examine when and why GKBA fails in a minimal yet informative setting, the Holstein
Oscar Moreno Segura, Yaroslav Pavlyukh, Riku Tuovinen   +2 more
wiley   +1 more source

Special solutions of the optical soliton eigenvalue problem [PDF]

, 1988
Electromagnetic pulse propagation in optical fibres is described by the non-linear Schrodinger equation. The solutions, or solitons, remain completely unchanged as they propagate along the fibre.
Breen, Kevin
core