Tootfinder

VHU-Net: Variational Hadamard U-Net for Body MRI Bias Field Correction
Xin Zhu
https://arxiv.org/abs/2506.19181 https://arxiv.org/pdf…

VHU-Net: Variational Hadamard U-Net for Body MRI Bias Field Correction
Bias field artifacts in magnetic resonance imaging (MRI) scans introduce spatially smooth intensity inhomogeneities that degrade image quality and hinder downstream analysis. To address this challenge, we propose a novel variational Hadamard U-Net (VHU-Net) for effective body MRI bias field correction. The encoder comprises multiple convolutional Hadamard transform blocks (ConvHTBlocks), each integrating convolutional layers with a Hadamard transform (HT) layer. Specifically, the HT layer perfo…

Development of MR spectral analysis method robust against static magnetic field inhomogeneity
Shuki Maruyama, Hidenori Takeshima
https://arxiv.org/abs/2506.20897

Development of MR spectral analysis method robust against static magnetic field inhomogeneity
Purpose:To develop a method that enhances the accuracy of spectral analysis in the presence of static magnetic field B0 inhomogeneity. Methods:The authors proposed a new spectral analysis method utilizing a deep learning model trained on modeled spectra that consistently represent the spectral variations induced by B0 inhomogeneity. These modeled spectra were generated from the B0 map and metabolite ratios of the healthy human brain. The B0 map was divided into a patch size of subregions, and t…

Mixed-Mode In-Memory Computing: Towards High-Performance Logic Processing In A Memristive Crossbar Array
Nan Du, Ilia Polian, Christopher Bengel, Kefeng Li, Ziang Chen, Xianyue Zhao, Uwe Huebner, Li-Wei Chen, Feng Liu, Massimiliano Di Ventra, Stephan Menzel, Heidemarie Krueger
https://arxiv.org/abs/2506.19063

Mixed-Mode In-Memory Computing: Towards High-Performance Logic Processing In A Memristive Crossbar Array
In-memory computing is a promising alternative to traditional computer designs, as it helps overcome performance limits caused by the separation of memory and processing units. However, many current approaches struggle with unreliable device behavior, which affects data accuracy and efficiency. In this work, the authors present a new computing method that combines two types of operations,those based on electrical resistance and those based on voltage, within each memory cell. This design improv…

A data-based notion of quantiles on Hadamard spaces
Ha-Young Shin, Hee-Seok Oh
https://arxiv.org/abs/2506.12534 https://arxiv.org/pdf…

A data-based notion of quantiles on Hadamard spaces
This paper defines an alternative notion, described as data-based, of geometric quantiles on Hadamard spaces, in contrast to the existing methodology, described as parameter-based. In addition to having the same desirable properties as parameter-based quantiles, these data-based quantiles are shown to have several theoretical advantages related to large-sample properties like strong consistency and asymptotic normality, breakdown points, extreme quantiles and the gradient of the loss function. …

@…
The oldest ant fossil ever discovered had forward-facing scythe-like jaws it used to hunt, according to a new study in Current Biology. 
Now the oldest ant specimen known to science, the roughly half-inch-long 113-million-year-old impression preserved in limestone was found in northeastern Brazil, and is a new genus belonging to the “hell ant” subfamily Haidomyrmecinae. Hell ants only lived during the Cretaceous period, which ended 66 million years ago. 🧵

Non-affine Families of 8 x 8 Complex Hadamard Matrices
Tuomo Valtonen
https://arxiv.org/abs/2505.22947 https://arxiv.org/pdf/2505.229…

Non-affine Families of 8 x 8 Complex Hadamard Matrices
Six non-affine 3-parameter families of complex Hadamard matrices of order 8 are presented. These families contain Hadamard matrices that are not equivalent to any previously known Hadamard matrices in the literature. Each family arises from unimodular points of an affine variety defined by palindromic polynomials. The families are given as an image of a function that solves the corresponding system of polynomials on a domain that guarantees unimodularity of the solutions

A noncommutative construction of families of biunitary matrices and application to subfactors
Keshab Chandra Bakshi, Satyajit Guin, Guruprasad
https://arxiv.org/abs/2506.14351

A noncommutative construction of families of biunitary matrices and application to subfactors
We introduce a construction that, given a pair (u,v) of complex Hadamard matrices of the same order, generates infinitely many biunitary matrices of varying (and distinct) orders. As a key application, this framework yields nested sequences of vertex model subfactors that are not a tower of downward basic construction. Notably, the construction is noncommutative: interchanging the matrices (i.e., considering (v,u) instead of (u,v)) can lead to non-isomorphic subfactors. Focusing on the Hadamard…

Functional data decomposition reveals unexpectedly strong soil moisture-precipitation coupling over the Great Plains
Yifu Gao, Runze Li, Efi Foufoula-Georgiou, Jasper A. Vrugt
https://arxiv.org/abs/2506.13939

Functional data decomposition reveals unexpectedly strong soil moisture-precipitation coupling over the Great Plains
Soil moisture-precipitation coupling (SMPC) plays a critical role in Earth's water and energy cycles but remains difficult to quantify due to synoptic-scale variability and the complex interplay of land-atmosphere processes. Here, we apply high-dimensional model representation (HDMR) to functionally decompose the structural, correlative, and cooperative contributions of key land-atmosphere variables to precipitation. Benchmark tests confirm that HDMR overcomes limitations of commonly used corre…

Randomised composite linear-combination-of-unitaries: its role in quantum simulation and observable estimation
Jinzhao Sun, Pei Zeng
https://arxiv.org/abs/2506.15658

Randomised composite linear-combination-of-unitaries: its role in quantum simulation and observable estimation
Randomisation is widely used in quantum algorithms to reduce the number of quantum gates and ancillary qubits required. A range of randomised algorithms, including eigenstate property estimation by spectral filters, Hamiltonian simulation, and perturbative quantum simulation, though motivated and designed for different applications, share common features in the use of unitary decomposition and Hadamard-test-based implementation. In this work, we start by analysing the role of randomised linear-…

Hadamard Encoded Row Column Ultrasonic Expansive Scanning (HERCULES) with Bias-Switchable Row-Column Arrays
Darren Olufemi Dahunsi, Randy Palmar, Tyler Henry, Mohammad Rahim Sobhani, Negar Majidi, Joy Wang, Afshin Kashani Ilkhechi, Jeremy Brown, Roger Zemp
https://arxiv.org/abs/2506.11443

Hadamard Encoded Row Column Ultrasonic Expansive Scanning (HERCULES) with Bias-Switchable Row-Column Arrays
Top-Orthogonal-to-Bottom-Electrode (TOBE) arrays, also known as bias-switchable row-column arrays (RCAs), allow for imaging techniques otherwise impossible for non-bias-switachable RCAs. Hadamard Encoded Row Column Ultrasonic Expansive Scanning (HERCULES) is a novel imaging technique that allows for expansive 3D scanning by transmitting plane or cylindrical wavefronts and receiving using Hadamard-Encoded-Read-Out (HERO) to perform beamforming on what is effectively a full 2D synthetic receive a…