Results 71 to 80 of about 7,594,968 (240)

Subequivalence relations and positive-definite functions

open access: yesGroups, Geometry, and Dynamics, 2009
We study a positive-definite function associated with a countable, measure-preserving equivalence relation, which can be used to measure quantitatively the proximity of subequivalence relations. Combined with a co-inducing construction introduced by Epstein and earlier work of Ioana, this can be used to construct many mixing actions of countable groups
Adrian Ioana   +2 more
openaire   +5 more sources

Do Politically Motivated Import Bans Leave Lasting Scars? Evidence From Australian–Chinese Beef Trade

open access: yesAgribusiness, EarlyView.
ABSTRACT In May 2020, China abruptly suspended imports from several major Australian beef processors, escalating a diplomatic dispute between the two countries. This trade measure disrupted one of the largest beef export relationships in the world almost overnight.
K. Aleks Schaefer, Youngjune Kim
wiley   +1 more source

A Unifying Approach to Self‐Organizing Systems Interacting via Conservation Laws

open access: yesAdvanced Intelligent Discovery, EarlyView.
The article develops a unified way to model and analyze self‐organizing systems whose interactions are constrained by conservation laws. It represents physical/biological/engineered networks as graphs and builds projection operators (from incidence/cycle structure) that enforce those constraints and decompose network variables into constrained versus ...
F. Barrows   +7 more
wiley   +1 more source

Explaining the Origin of Negative Poisson's Ratio in Amorphous Networks With Machine Learning

open access: yesAdvanced Intelligent Discovery, EarlyView.
This review summarizes how machine learning (ML) breaks the “vicious cycle” in designing auxetic amorphous networks. By transitioning from traditional “black‐box” optimization to an interpretable “AI‐Physics” closed‐loop paradigm, ML is shown to not only discover highly optimized structures—such as all‐convex polygon networks—but also unveil hidden ...
Shengyu Lu, Xiangying Shen
wiley   +1 more source

Robust Reinforcement Learning Control Framework for a Quadrotor Unmanned Aerial Vehicle Using Critic Neural Network

open access: yesAdvanced Intelligent Systems, Volume 7, Issue 3, March 2025.
Quadrotor unmanned aerial vehicle control is critical to maintain flight safety and efficiency, especially when facing external disturbances and model uncertainties. This article presents a robust reinforcement learning control scheme to deal with these challenges.
Yu Cai   +3 more
wiley   +1 more source

Motion and Morphology Planning for Autonomous Manipulation in Clutter With a Shape‐Shifting, Variable‐Stiffness Robot

open access: yesAdvanced Intelligent Systems, EarlyView.
A hybrid mobile robot with a modular Variable‐Stiffness Bridge transitions between a rigid locomotion platform and a flexible, shape‐conforming body. By enclosing objects within its deformable structure rather than relying on dedicated end effectors, the robot achieves orientation‐regulated planar transport, with conformal contact quality shown to ...
Luiza Labazanova   +5 more
wiley   +1 more source

Beyond Canonical CO Oxidation: Structural and Evolutionary Insights Into a Non‐Canonical Carbon Monoxide Dehydrogenase

open access: yesAngewandte Chemie, EarlyView.
Clade B carbon monoxide dehydrogenases (CODHs) remain enigmatic, diverging from canonical CODHs in structure and function. Here, we present the first characterization of Ruminococcus flavefaciens CODH (RfCODH), revealing occluded substrate pathways and attenuated CO oxidation activity.
Maximilian Böhm   +6 more
wiley   +2 more sources

Contact Force Estimation in Human–Robot Collaboration: A Case Study on Heavyweight Robotic Manipulators

open access: yesAdvanced Intelligent Systems, EarlyView.
The method presented in this paper provides a practical sensorless solution for estimating both contact force and contact location using only standard joint encoders and an available robot dynamic model. By reformulating the contact estimation problem using a single scalar equivalent contact parameter, the approach enables fast and robust computation ...
Thanh‐Quan Ta, Shyh‐Leh Chen
wiley   +1 more source

Schoenberg's Problem on Positive Definite Functions

open access: yes, 1992
If $n \ge 3$, $q>2$ and $β> 0$ then the function $\exp(-(|x_1|^q+|x_2|^q+\dots+|x_n|^q)^{β/q})$\ is not positive definite. This result gives an answer to a question posed by I.J.~Schoenberg in 1938. This text is an authorized English translation of the paper published in Russian in Algebra and Analysis 3(1991), \#3, p.78--85.
openaire   +3 more sources

Positive definite functions on a regular domain

open access: yesIMA Journal of Numerical Analysis
Abstract We define positive and strictly positive definite functions on a domain and study these functions on a list of regular domains. The list includes the unit ball, conic surface, hyperbolic surface, solid hyperboloid and the simplex.
Martin D. Buhmann, Yuan Xu
openaire   +2 more sources

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