Results 101 to 110 of about 12,109 (301)

A partial envelope approach for modelling multivariate spatial‐temporal data

open access: yesCanadian Journal of Statistics, EarlyView.
Abstract In the new era of big data, modelling multivariate spatial‐temporal data is a challenging task due to both the high dimensionality of the features and complex associations among the responses across different locations and time points.
Reisa Widjaja   +3 more
wiley   +1 more source

Toeplitz Jacobian Method for Nonlinear Double-Periodic Excitations

open access: yesShock and Vibration, 1997
The Toeplitz Jacobian matrix method is an efficient algorithm for computing the steady state solutions of nonlinear periodic vibration. In this paper, the method is generalized by using multiple time scales to double-periodic solutions in a multi ...
T. Ge, A.Y.T. Leung
doaj   +1 more source

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

open access: yesCommunications 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   +2 more
wiley   +1 more source

A Superlinearly Convergent Method for the Generalized Complementarity Problem over a Polyhedral Cone

open access: yesJournal of Applied Mathematics, 2013
Making use of a smoothing NCP-function, we formulate the generalized complementarity problem (GCP) over a polyhedral cone as an equivalent system of equations. Then we present a Newton-type method for the equivalent system to obtain a solution of the GCP.
Fengming Ma, Gang Sheng, Ying Yin
doaj   +1 more source

Constrained regularization methods for ozone profile retrieval from UV/VIS nadir spectrometers

open access: yes, 2009
In this paper we present several constrained regularization methods for ozone profile retrieval from UV/VIS nadir sounding instruments such as GOME, SCIAMACHY, OMI and GOME-2.
Doicu, Adrian   +2 more
core   +1 more source

Quenching the Hubbard Model: Comparison of Nonequilibrium Green's Function Methods

open access: yesContributions to Plasma Physics, EarlyView.
ABSTRACT We benchmark nonequilibrium Green's function (NEGF) approaches for interaction quenches in the half‐filled Fermi–Hubbard model in one and two dimensions. We compare fully self‐consistent two‐time Kadanoff–Baym equations (KBE), the generalized Kadanoff–Baym ansatz (GKBA), and the recently developed NEGF‐based quantum fluctuations approach (NEGF‐
Jan‐Philip Joost   +3 more
wiley   +1 more source

Numerical solution of fuzzy non-linear equations under generalized trapezoidal fuzziness by Newton–Raphson method

open access: yesFranklin Open
In the real world, we are faced with many problems that cannot be easily described by crisp values, as there is always some uncertainty involved in real-life situations and in those situations, we end up receiving fuzzy values rather than crisp ones in ...
Sanjoy Basu, G.S. Mahapatra
doaj   +1 more source

Using generalized estimating equations with regression splines to improve analysis of butterfly transect data

open access: yes, 2008
Surveying animal populations is an important aspect of wildlife management. Distinguishing trend from random fluctuations and quantifying trend are key goals in any analysis.
Brewer, Ciara
core  

Convergence analysis of a regularized Newton method with generalized regularization terms for unconstrained convex optimization problems [PDF]

open access: yes
This paper presents a regularized Newton method (RNM) with generalized regularization terms for unconstrained convex optimization problems. The generalized regularization includes quadratic, cubic, and elastic net regularizations as special cases ...
Yamashita, Nobuo, Yamakawa, Yuya
core   +1 more source

Ultrafast Transitions in X‐Ray Irradiated Solids

open access: yesContributions to Plasma Physics, EarlyView.
ABSTRACT In this review, we present current developments on modeling ultrafast transitions in solids triggered by intense, atto‐ to femtosecond pulses from X‐ray free electron lasers. This specific irradiation regime requires dedicated simulation tools based on theoretical and computational methods, involving the elements of classical and quantum ...
Sebastião Antunes   +3 more
wiley   +1 more source

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