Results 111 to 120 of about 2,134,041 (173)

Sparse graph signals – uncertainty principles and recovery

GAMM-Mitteilungen, Volume 48, Issue 2, June 2025.
ABSTRACT We study signals that are sparse either on the vertices of a graph or in the graph spectral domain. Recent results on the algebraic properties of random integer matrices as well as on the boundedness of eigenvectors of random matrices imply two types of support size uncertainty principles for graph signals.
Tarek Emmrich, Martina Juhnke, Stefan Kunis   +2 more
wiley   +1 more source

An Adaptive Watermarking Process in Hadamard Transform [PDF]

arXiv, 2014
An adaptive visible/invisible watermarking scheme is done to prevent the privacy and preserving copyright protection of digital data using Hadamard transform based on the scaling factor of the image. The value of scaling factor depends on the control parameter. The scaling factor is calculated to embedded the watermark.
arxiv  

Flood Classification and Improved Loss Function by Combining Deep Learning Models to Improve Water Level Prediction in a Small Mountain Watershed

Journal of Flood Risk Management, Volume 18, Issue 2, June 2025.
ABSTRACT Floods are major natural disasters that present considerable challenges to socioeconomic and ecological systems. Flash floods are highly nonlinear and exhibit rapid spatiotemporal variability. Existing methods struggle to capture these features, leading to suboptimal long‐term and peak flood prediction accuracy.
Rukai Wang, Ximin Yuan, Fuchang Tian, Minghui Liu, Xiujie Wang, Xiaobin Li, Minrui Wu   +6 more
wiley   +1 more source

A Fourier-analytic Approach to Counting Partial Hadamard Matrices [PDF]

arXiv, 2010
In this paper, we study a family of lattice walks which are related to the Hadamard conjecture. There is a bijection between paths of these walks which originate and terminate at the origin and equivalence classes of partial Hadamard matrices. Therefore, the existence of partial Hadamard matrices can be proved by showing that there is positive ...
arxiv  

Ultra‐high temporal resolution 4D angiography using arterial spin labeling with subspace reconstruction

Magnetic Resonance in Medicine, Volume 93, Issue 5, Page 1924-1941, May 2025.
Abstract Purpose To achieve ultra‐high temporal resolution non‐contrast 4D angiography with improved spatiotemporal fidelity. Methods Continuous data acquisition using 3D golden‐angle sampling following an arterial spin labeling preparation allows for flexibly reconstructing 4D dynamic angiograms at arbitrary temporal resolutions. However, k‐space data
Qijia Shen, Wenchuan Wu, Mark Chiew, Yang Ji, Joseph G. Woods, Thomas W. Okell   +5 more
wiley   +1 more source

Discrete Hartley matrix transform precoding-based OFDM system to reduce the high PAPR

ICT Express, 2019
The high peak-to-average power ratio (PAPR) is one of the major drawbacks of the orthogonal frequency division multiplexing (OFDM) systems that make non-linear distortion in practical implementation of high power amplifier (HPA).
Abbas Ali Sharifi
doaj  

Series Transformation Formulas of Euler Type, Hadamard Product of Functions, and Harmonic Number Identities [PDF]

Indian J. Pure and Appl. Math., 42 (2011), 371-387, 2009
The integral representation of the Hadamard product of two functions is used to prove several Euler-type series transformation formulas. As applications we obtain three binomial identities involving harmonic numbers and an identity for the Laguerre polynomials.
arxiv  

Third trimester fetal 4D flow MRI with motion correction

Magnetic Resonance in Medicine, Volume 93, Issue 5, Page 1969-1983, May 2025.
Abstract Purpose To correct maternal breathing and fetal bulk motion during fetal 4D flow MRI. Methods A Doppler‐ultrasound fetal cardiac‐gated free‐running 4D flow acquisition was corrected post hoc for maternal respiratory and fetal bulk motion in separate automated steps, with optional manual intervention to assess and limit fetal motion artifacts ...
Reagan M. Tompkins, Takashi Fujiwara, Eric M. Schrauben, Lorna P. Browne, Joost van Schuppen, Sally‐Ann Clur, Richard M. Friesen, Erin K. Englund, Alex J. Barker, Pim van Ooij   +9 more
wiley   +1 more source

Encryption of Binary and Non-Binary Data Using Chained Hadamard Transforms [PDF]

arXiv, 2010
This paper presents a new chaining technique for the use of Hadamard transforms for encryption of both binary and non-binary data. The lengths of the input and output sequence need not be identical. The method may be used also for hashing.
arxiv  

Predicting Sudden Stratospheric Warmings Using Video Prediction Methods

Geophysical Research Letters, Volume 52, Issue 8, 28 April 2025.
Abstract Sudden Stratospheric Warmings (SSWs) are weather phenomena occurring in polar regions, and have a profound impact on mid‐latitude cold waves. In this paper, within a deep learning framework, we introduce video prediction techniques into SSW events forecasting for the first time.
Yuhao Du, Jiankai Zhang, Xinyuan Cheng, Yixiong Lu, Douwang Li, Wenshou Tian   +5 more
wiley   +1 more source