Results 131 to 140 of about 1,179,942 (315)

Simultaneous Cerebral Blood Flow and Cerebrovascular Reactivity Obtained From Novel Multi‐Band Multi‐Echo Pseudo‐Continuous Arterial Spin Labeling (M2‐PCASL) Sequence: A Test–Retest Reliability Study

Magnetic Resonance in Medicine, Volume 96, Issue 1, Page 37-48, July 2026.
ABSTRACT Purpose We aim to assess the reliability of cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) obtained simultaneously from a novel multi‐band pseudo‐continuous arterial spin labeling (M2‐PCASL) sequence and hypercapnic gas challenge, to examine factors influencing CBF variability, and to evaluate the impact of carbon dioxide (CO2)
Jody Todd, Maria‐Julieta Mateos, Ibraheem Budeir, Deqiang Qiu   +3 more
wiley   +1 more source

Optimization and engineering verification of excitation scheme for aircraft ground vibration test

Hangkong gongcheng jinzhan
Ground vibration test is an important part of aircraft model development and strength verification. In aircraft ground vibration test，an appropriate excitation scheme can significantly shorten the test's period and improve the accuracy of mode ...
CHEN Haoyu, WANG Binwen, SONG Qiaozhi, LI Xiaodong   +3 more
doaj   +1 more source

Autonomy for MRI Field Cameras: Synchronization, Self‐Calibration, and Sequence Detection

Magnetic Resonance in Medicine, Volume 96, Issue 1, Page 485-498, July 2026.
ABSTRACT Purpose This work aims to provide a workflow for operating NMR field probes in MR scanners independently of pulse programming, scanner TTL trigger pulses and dedicated calibration sequences. Methods An independent timing system and limited prior knowledge about relative probe positions enable synchronous field measurement, probe position ...
Oskar Björkqvist, Klaas P. Pruessmann
wiley   +1 more source

Distributional and Tail‐Dependent Perspectives in Economic Relationships: A Review of Quantile Regression Application

Journal of Economic Surveys, Volume 40, Issue 3, Page 1637-1652, July 2026.
ABSTRACT There is an increased proportion of studies using quantile‐based regression methodology (QR) in economics. They offer a robust alternative to classical mean regressions, which can estimate non‐normal variables with distributional heterogeneity in the dependent variable.
Shajara Ul‐Durar, Konstantinos A. Dimitriadis, Noman Arshed, Marco De Sisto, Hamidreza Harati   +4 more
wiley   +1 more source

VLSI implementation of a high-speed iterative sorted MMSE QR decomposition

The QR decomposition is an important, but often underestimated prerequisite for pseudo- or non-linear detection methods such as successive interference cancellation or sphere decoding for multiple-input multiple-output (MIMO) systems.
Fichtner, W., Burg, A., Luethi, P., Felber, N., Haene, S., Perels, D.   +5 more
core   +1 more source

Givens Rotations for QR Decomposition, SVD and PCA over Database Joins

, 2023
This article introduces Figaro, an algorithm for computing the upper-triangular matrix in the QR decomposition of the matrix defined by the natural join over relational data.
Vortmeier, Nils, Olteanu, Dan, Živanović, Đorđe   +2 more
core  

Econometrics at the Extreme: From Quantile Regression to QFAVAR1

Journal of Economic Surveys, Volume 40, Issue 3, Page 1672-1686, July 2026.
ABSTRACT This paper surveys quantile modelling from its theoretical origins to current advances. We organize the literature and present core econometric formulations and estimation methods for: (i) cross‐sectional quantile regression; (ii) quantile time series models and their time series properties; (iii) quantile vector autoregressions for ...
Stéphane Goutte, Konstantinos N. Konstantakis, Dimitris Konstantios, Panayotis G. Michaelides, Arsenios‐Georgios N. Prelorentzos   +4 more
wiley   +1 more source

Random Diophantine equations in the primes

Mathematika, Volume 72, Issue 3, July 2026.
Abstract We consider equations of the form a1x1k+⋯+asxsk=0$a_{1}x_{1}^{k}+\cdots +a_{s}x_{s}^{k}=0$ where the variables xi$x_{i}$ are all taken to be primes. We define an analogue of the Hasse principle for solubility in the primes (which we call the prime Hasse principle), and prove that, whenever k⩾2$k\geqslant 2$, s⩾3k+2$s\geqslant 3k+2$, this holds
Philippa Holdridge
wiley   +1 more source

A New and Simple Method to Get the Priority Vector for Reciprocal Matrices [PDF]

Operations Research and Decisions
A new optimization method is proposed to find the priority vector of a non-consistent reciprocal matrix, which leads to the solution of a constrained least-squares problem, specially suited for large matrices.
Julio Benítez, Carlos Serra-Jiménez
doaj  

The Role of Daily and Monthly Bias Corrected Data in Preserving the Monthly Cross‐Correlation Between Precipitation and Temperature

International Journal of Climatology, Volume 46, Issue 7, 15 June 2026.
Daily bias‐correction aggregated to monthly scale preserves the cross‐correlation between precipitation and temperature better than direct monthly bias‐correction. The Canonical Correlation Analysis (CCA) method outperforms Quantile Regression (QR) and MACA, yielding lower bias and higher accuracy, highlighting its suitability for multivariate climate ...
Chingka Kalai, Shiqi Fang, Rajarshi Das Bhowmik, A. Sankarasubramanian   +3 more
wiley   +1 more source