Results 111 to 120 of about 1,971,484 (243)

New views of some invariants associated with the Cartesian 2D velocity gradient tensor

Quarterly Journal of the Royal Meteorological Society, EarlyView.
Vorticity and divergence of horizontal flow are fundamental quantities in meteorology; both are linear functions of the four elements of the 2D velocity gradient tensor and both are formally unchanged under coordinate rotation. We explore four quadratic functions of the elements that are geometrically invariant in this sense, finding some novel ...
I. Roulstone, S. A. Clough, A. A. White
wiley   +1 more source

A conjecture of Warnaar-Zudilin from deformations of lie superalgebras. [PDF]

Res Math Sci
Creutzig T, Garner N.
europepmc   +1 more source

Low‐order system for eddy growth in the storm track

Quarterly Journal of the Royal Meteorological Society, EarlyView.
Reanalysis data for the North Atlantic storm track are used to construct a low‐order model that optimally fits the observed interaction between the mean flow and baroclinic eddies. The resulting model is a certain type of predator–prey model. It explains various properties of the storm track, including why eddies grow linearly with the Eady growth rate,
Maarten H. P. Ambaum, Thomas H. A. Frame
wiley   +1 more source

Rigorous Bound on Hydrodynamic Diffusion for Chaotic Open Spin Chains. [PDF]

J Stat Phys
Ampelogiannis D, Doyon B.
europepmc   +1 more source

Data‐driven emulation of flow‐dependent background‐error variance in variational data assimilation

Quarterly Journal of the Royal Meteorological Society, EarlyView.
A machine‐learning approach is developed to emulate flow‐dependent background‐error variance within a variational data assimilation framework. The method reproduces uncertainty information that would normally require a 50‐member ensemble using only five members, while maintaining comparable observation fit and forecast performance.
Wei Pan, Massimo Bonavita, Marcin Chrust, Elías Hólm   +3 more
wiley   +1 more source

Getting to the root of the problem: sums of squares for limits of trees. [PDF]

Math Program
Brosch D, Puges D.
europepmc   +1 more source

Sliding Mode Control in Aerospace Applications: A Survey

International Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT Sliding mode control (SMC) enjoys robustness to matched and unmatched (in the case of minimum phase input‐output dynamics) bounded perturbations, and finite time convergence. Second‐order and higher‐order sliding mode control systems (2‐SMC/HOSMC) retain all the advantages of sliding mode control, but in addition can be applied to systems of ...
Yuri Shtessel, Christopher Edwards
wiley   +1 more source

Tensor Operational Mathematics and Tensor Meta-Operational Mathematics:A Rigorous Extension of Iteration Counts and Meta-Operations to Multilinear Algebra

This two-part treatise rigorously extends the frameworks of Operational Mathematics and Meta-Operational Mathematics to the domain of tensor algebra and multilinear maps. In Part I, we systematically generalize the notion of iteration count—the number of times an operation is applied—from natural numbers to integers, rationals, reals, and complex ...
openaire   +1 more source

Classification of prime modules of quantum affine algebras corresponding to 2-column tableaux. [PDF]

J Algebr Comb (Dordr)
Early N, Li JR.
europepmc   +1 more source

High‐Order Sliding‐Mode control for MIMO Systems

International Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT This paper extends Lyapunov‐based homogeneous high‐order sliding‐mode control to a class of uncertain non‐square multi‐input multi‐output (MIMO) nonlinear systems with a well‐defined vector relative degree. The considered systems admit a normal‐form representation with an uncertain but full‐row‐rank input‐gain matrix.
Jaime A. Moreno, Angel Mercado‐Uribe
wiley   +1 more source