Results 111 to 120 of about 8,682 (260)

Optimizing Selective RF Pulses for Enhanced Signal Stability in Turbo Spin Echo Using a Differentiable Extended Phase Graph Model

open access: yesMagnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To improve slice profile consistency across echo trains in turbo spin echo (TSE) imaging, thereby reducing image blurring and increasing the accuracy of multi echo spin echo T2$$ {T}_2 $$ mapping. Methods Excitation and refocusing RF pulses were optimized for TSE using a differentiable extended phase graph model that incorporates the ...
Madison M. Augelli   +3 more
wiley   +1 more source

Calculus in O-algebras with positive squares

open access: yesBulletin of the Belgian Mathematical Society - Simon Stevin, 2004
Let $A$ be an $\mathcal{O}$-algebra with positive squares and $F\left( X_{1},...,X_{n}\right) \in\linebreak\mathbb{R}^{+}\left[ X_{1},...,X_{n}\right] $ be a homogeneous polynomial of degree $p$ $\left( p\in\mathbb{N}^{\ast },\text{ }p\neq2\right) $. It is shown that for all $0\leq a_{1},...,a_{n}\in A$ there exists $0\leq a$ $\in A$ such that $F\left(
openaire   +2 more sources

Bending Analysis of Thickness‐ and Shear‐Deformable Materially Imperfect Composite Shells With von Kármán‐Type Geometric Nonlinearities

open access: yesInternational Journal of Mechanical System Dynamics, EarlyView.
ABSTRACT Geometrically nonlinear static analysis of materially imperfect composite doubly curved shells is investigated via the generalised differential quadrature method. The effects of both shear and thickness deformation are considered through a thickness‐ and shear‐deformable third‐order theory formulated in curvilinear coordinates, while the ...
Behrouz Karami   +3 more
wiley   +1 more source

Robustness Assessment of Public Transport Networks in Various Graph Representations: Systematic Review, Decision Support, and Case Study

open access: yesNetworks, EarlyView.
ABSTRACT The analysis of certain properties of the underlying graph of a public transport network generates insights about the network's structure. Hereby, the choice of the graph representation depends on a trade‐off between complexity reduction and information preservation to adequately model a public transport network.
Michael Palk   +2 more
wiley   +1 more source

Impact of Packaging and Recycling Systems on Material Recirculation: A Stage‐Decomposition Model

open access: yesPackaging Technology and Science, EarlyView.
A system‐level view emerges from decomposing recycling into four stages (participation, collection, sorting and process yield), diagnosing constraints and targeting interventions. Cumulative equivalent uses (CEUs) quantify long‐term retention, revealing marginal improvements at high baselines generate disproportionately larger gains than low‐baseline ...
Diogo Figueirinhas   +3 more
wiley   +1 more source

Output Feedback Design for Parameter Varying Systems Subject to Persistent Disturbances and Control Rate Constraints

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT This paper develops a framework for designing output feedback controllers for constrained linear parameter‐varying systems that experience persistent disturbances. We specifically propose an incremental parameter‐varying output feedback control law to address control rate constraints, as well as state and control amplitude constraints.
Jackson G. Ernesto   +2 more
wiley   +1 more source

Recursive Feasibility of Nonlinear Stochastic Model Predictive Control With Gaussian Process Dynamics

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT Data‐based learning of system dynamics allows model‐based control approaches to be applied to systems with partially unknown dynamics. Gaussian process regression is a preferred approach that outputs not only the learned system model but also the variance of the model, which can be seen as a measure of uncertainty.
Daniel Landgraf   +2 more
wiley   +1 more source

The role of identification in data‐driven policy iteration: A system theoretic study

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
Abstract The goal of this article is to study fundamental mechanisms behind so‐called indirect and direct data‐driven control for unknown systems. Specifically, we consider policy iteration applied to the linear quadratic regulator problem. Two iterative procedures, where data collected from the system are repeatedly used to compute new estimates of ...
Bowen Song, Andrea Iannelli
wiley   +1 more source

Initial State Privacy of Nonlinear Systems on Riemannian Manifolds

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT In this paper, we investigate initial state privacy protection for discrete‐time nonlinear closed systems. By capturing Riemannian geometric structures inherent in such privacy challenges, we refine the concept of differential privacy through the introduction of an initial state adjacency set based on Riemannian distances.
Le Liu, Yu Kawano, Antai Xie, Ming Cao
wiley   +1 more source

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