Results 101 to 110 of about 8,872 (261)

Carbon monoxide adsorption on NaY zeolite and impregnated with 5% niobium: Characteristics and fixed‐bed study

The Canadian Journal of Chemical Engineering, EarlyView.
Schematic of the CO adsorption process in a fixed‐bed column containing pure NaY zeolite and Nb‐modified NaY (NaY–5%Nb). On the left, breakthrough curves and temperature profiles highlight the dynamic performance and thermal effects during CO adsorption.
Elson Oliveira, Karina Querne de Carvalho, Erika Pereira Felix, Roberta C. P. Rizzo‐Domingues   +3 more
wiley   +1 more source

MLEce: Statistical inference for asymptotically efficient closed-form estimators in R

SoftwareX
Maximum likelihood estimation is a classical method with useful properties like efficiency, consistency, and asymptotic normality. However, the maximum likelihood estimator (MLE) cannot be in closed form in many distributions.
Jun Zhao, Yu-Kwang Kim, Yu-Hyeong Jang, Jae Ho Chang, Sang Kyu Lee, Hyoung-Moon Kim   +5 more
doaj   +1 more source

Asymptotic properties of cross‐classified sampling designs

Canadian Journal of Statistics, EarlyView.
Abstract We investigate the family of cross‐classified sampling designs across an arbitrary number of dimensions. We introduce a variance decomposition that enables the derivation of general asymptotic properties for these designs and the development of straightforward and asymptotically unbiased variance estimators.
Jean Rubin, Guillaume Chauvet
wiley   +1 more source

Asymptotic normality of the test statistics for the unified relative dispersion and relative variation indexes. [PDF]

J Appl Stat, 2020
Touré AY, Dossou-Gbété S, Kokonendji CC.   +2 more
europepmc   +1 more source

Jackknife bias‐corrected variance estimation for the generalized regression estimator

Canadian Journal of Statistics, EarlyView.
Abstract Commonly used variance estimators for the generalized regression estimator (GREG) are based on Taylor linearization and jackknife. Traditionally, a jackknife GREG variance estimator is obtained by jackknifing GREG, which consists of computing GREG from each of several subsamples of the parent sample, and estimating the variance of the parent ...
Marius Stefan, J.N.K Rao
wiley   +1 more source

A partial envelope approach for modelling multivariate spatial‐temporal data

Canadian 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, Wenbo Wu, Victor De Oliveira, Keying Ye   +3 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

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

Structured Distance to Normality of Dirichlet–Neumann Tridiagonal Toeplitz Matrices

Axioms
This paper conducts a rigorous study on the spectral properties and operator-space distances of perturbed Dirichlet–Neumann tridiagonal (PDNT) Toeplitz matrices, with emphasis on their asymptotic behaviors. We establish explicit closed-form solutions for
Zhaolin Jiang, Hongxiao Chu, Qiaoyun Miao, Ziwu Jiang   +3 more
doaj   +1 more source

Compact Manifolds With Unbounded Nilpotent Fundamental Groups and Positive Ricci Curvature

Communications on Pure and Applied Mathematics, EarlyView.
ABSTRACT It follows from the work of Kapovitch and Wilking that a closed manifold with nonnegative Ricci curvature has a uniformly almost nilpotent fundamental group. Leftover questions and conjectures, have asked if in this context the fundamental group is actually uniformly almost abelian. The main goal of this work is to construct examples (Mk9,gk)$(
Elia Bruè, Aaron Naber, Daniele Semola
wiley   +1 more source