Results 31 to 40 of about 3,321 (184)

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

Front Propagation Through a Perforated Wall

Communications on Pure and Applied Mathematics, EarlyView.
ABSTRACT We consider a bistable reaction– diffusion equation ut=Δu+f(u)$u_t=\Delta u +f(u)$ on RN${\mathbb {R}}^N$ in the presence of an obstacle K$K$, which is a wall of infinite span with many holes. More precisely, K$K$ is a closed subset of RN${\mathbb {R}}^N$ with smooth boundary such that its projection onto the x1$x_1$‐axis is bounded and that ...
Henri Berestycki, François Hamel, Hiroshi Matano   +2 more
wiley   +1 more source

A Geometric Characterization of Steady Laminar Flow

Communications on Pure and Applied Mathematics, EarlyView.
ABSTRACT We study the steady states of the Euler equations on the periodic channel or annulus. We show that if these flows are laminar (layered by closed non‐contractible streamlines which foliate the domain), then they must be either parallel or circular flows.
Theodore D. Drivas, Marc Nualart
wiley   +1 more source

Cobalt Single‐Atom Sites Engineered in Poly(Heptazine Imide) Photocathodes as Benchmark for Alkaline Hydrogen Evolution: A Comparative Transition Metal Study

ENERGY &ENVIRONMENTAL MATERIALS, EarlyView.
Cobalt single‐atoms in poly(heptazine imide) photocathodes maximize active‐site availability and outperform Fe, Cu, and Na in alkaline hydrogen evolution. Atomic precision (not bulk loading) proves predominance, establishing a design principle for the next generation of solar fuel devices.
Izadora F. Reis, Gabriel A. A. Diab, Sachin Nenaniya, Marcos A. R. da Silva, Rayse M. Ferreira, Heer Shah, Geraldo M. G. da Silva, Andreas Hutzler, Mark Isaacs, Christian W. Lopes, Ivo F. Teixeira, Pablo Jiménez‐Calvo   +11 more
wiley   +1 more source

Verification of an Incompressible Viscoelastic Flow Solver Using the Method of Manufactured Solutions for Oldroyd‐B and Giesekus Constitutive Models

International Journal for Numerical Methods in Fluids, EarlyView.
This study utilizes the Method of Manufactured Solutions (MMS) to validate high‐order compact finite‐difference schemes for 2D incompressible viscoelastic flows. By applying Oldroyd‐B and Giesekus models to a lid‐driven cavity benchmark, the researchers rigorously assessed numerical accuracy across varying Reynolds and Weissenberg numbers.
Juniormar Organista, Leandro F. Souza, Célio Fernandes, Welton L. Costa, Aquisson T. G. da Silva, Antonio Castelo   +5 more
wiley   +1 more source

A New Implementation of Network GARCH Model for Stock Volatility and Co‐Volatility Forecasting

Journal of Forecasting, EarlyView.
ABSTRACT Volatility clustering and spillovers are key features of financial time series with many cross‐sectional assets. While network analysis links similar or correlated stocks and helps trace volatility spillovers, contemporary multivariate ARCH‐GARCH formulations struggle to represent structured network dependence and remain parsimonious.
Peiyi Zhou
wiley   +1 more source

Compact Single‐Shot Incoherent Edge Detection With a Polarization‐Multiplexed Metalens

Laser &Photonics Reviews, EarlyView.
A polarization‐sensitive metalens enables single‐shot incoherent edge detection by generating two polarization‐dependent images and digitally subtracting them to realize a high‐pass optical transfer function. ABSTRACT Edge detection under incoherent illumination is highly desirable for compact vision systems but remains challenging due to the lack of ...
Weiyan Li, Xiaotong Li, Youngsun Jeon, Hyeonsu Heo, Jaekyung Kim, Gyeongtae Kim, Shiqi Hu, Minsu Jeong, Cherry Park, Seokho Lee, Le Dai, Mu Qiao, Qi Zheng, Zheng Zhu, Zhaogang Dong, Chunying Guan, Jinhui Shi, Junsuk Rho   +17 more
wiley   +1 more source

Kernel Bounds for Parabolic Operators Having First‐Order Degeneracy at the Boundary

Mathematische Nachrichten, EarlyView.
ABSTRACT We study kernel estimates for parabolic problems governed by singular elliptic operators ∑i,j=1N+1qijDij+cDyy,cγ+1>0,γ=qN+1,N+1,$$\begin{equation*} \sum _{i,j=1}^{N+1}q_{ij}D_{ij}+c\frac{D_y}{y},\qquad \frac{c}{\gamma }+1>0, \quad \gamma =q_{N+1,N+1}, \end{equation*}$$in the half‐space R+N+1={(x,y):x∈RN,y>0}$\mathbb {R}^{N+1}_+=\lbrace (x,y ...
L. Negro, C. Spina
wiley   +1 more source

A highly accurate numerical method for solving boundary value problem of generalized Bagley‐Torvik equation

Mathematical Methods in the Applied Sciences, EarlyView.
A highly accurate numerical method is given for the solution of boundary value problem of generalized Bagley‐Torvik (BgT) equation with Caputo derivative of order 0<β<2$$ 0<\beta <2 $$ by using the collocation‐shooting method (C‐SM). The collocation solution is constructed in the space Sm+1(1)$$ {S}_{m+1}^{(1)} $$ as piecewise polynomials of degree at ...
Suzan Cival Buranay, Mtema James Chin, Nazim I. Mahmudov   +2 more
wiley   +1 more source

Exponential Stability of Higher Order Fractional Neutral Stochastic Differential Equation Via Integral Contractors

Mathematical Methods in the Applied Sciences, Volume 48, Issue 6, Page 6425-6446, April 2025.
ABSTRACT The well‐posedness results for mild solutions to the fractional neutral stochastic differential system with Rosenblatt process with Hurst index Ĥ∈12,1$$ \hat{H}\in \left(\frac{1}{2},1\right) $$ is discussed in this article. To demonstrate the results, the concept of bounded integral contractors is combined with the stochastic result and ...
Dimplekumar N. Chalishajar, Dhanalakshmi Kasinathan, Ramkumar Kasinathan, Ravikumar Kasinathan   +3 more
wiley   +1 more source