Results 121 to 130 of about 437,926 (227)

Coupled observation‐operator approximations in outer‐loop coupling data assimilation

Quarterly Journal of the Royal Meteorological Society, EarlyView.
We present a methodology for coupled variational data assimilation that allows the effect of coupled observation operators whilst maintaining separate minimisations across model components. This allows us to constrain the atmosphere, ocean, and sea‐ice components of our coupled model directly from satellite radiances. We illustrate the system in action
P. A. Browne, P. de Rosnay, A. J. Geer, S. Quesada‐Ruiz, T. Scanlon, E. Villeneuve   +5 more
wiley   +1 more source

Measures and Jacobians of singular random matrices

, 2009
This work studies the Jacobians of certain singular transformations and the corresponding measures which support the jacobian computations.
openaire   +2 more sources

Structure and Efficient Jacobian Calculation [PDF]

, 1996
Many computational tasks require the determination of the Jacobian matrix, at a given argument, for a large nonlinear system of equations. Calculation or approximation of a Newton step is a related task.
Thomas F. Coleman, Arun Verma, Verma, Arun, Coleman, Thomas F.   +3 more
core  

Enhancing severe convection forecasts with microwave radiance assimilation in limited‐area models

Quarterly Journal of the Royal Meteorological Society, EarlyView.
Microwave satellite radiances remain largely underexploited in convection‐permitting limited‐area models. We assess the assimilation of humidity‐sensitive radiances from the MHS instrument in the operational ICON‐2I model, improving the precipitation forecast of a severe convective event over the Marche region, Italy, substantially by correcting ...
Marcello Grenzi, Thomas Gastaldo, Virginia Poli, Chiara Marsigli, Tijana Janjic, Alberto Carrassi   +5 more
wiley   +1 more source

Modeling and Simulation of a 2SPU-RU Parallel Mechanism for a Prosthetic Ankle with Three Degrees of Freedom

Inventions
To assist an individual with an amputation in regaining daily quality of life, a 2SPU-RU type parallel mechanism was developed based on ankle biomechanics.
Victoria E. Abarca, Dante A. Elias
doaj   +1 more source

Unipotent Jacobian Matrices and Univalent Maps

, 1999
The Jacobian Conjecture would follow if it were known that real polynomial maps with a unipotent Jacobian matrix are injective. The conjecture that this is true even for $C^1$ maps is explored here. Some results known in the polynomial case are extended to the $C^1$ context, and some special cases are resolved.
openaire   +2 more sources

Feedback Linearisation with State Constraints

International Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT Feedback Linearisation (FBL) is a widely used technique that applies feedback laws to transform input‐affine nonlinear control systems into linear control systems, allowing for the use of linear controller design methods such as pole placement.
Songlin Jin, Yuanbo Nie, Morgan Jones
wiley   +1 more source

Validation of Neural Network Controllers for Uncertain Systems Using the Keep‐Close Approach: Robustness Analysis and Safety Verification

International Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT The safety verification of neural network (NN) controllers operating in uncertain environments characterized by unmodeled dynamics, nonlinearities, and time delays remains a fundamental challenge in robust control analysis. This article introduces a novel method, termed Keep‐Close, for analyzing the performance and robustness of uncertain ...
Abdelhafid Zenati, Nabil Aouf
wiley   +1 more source

Terrain‐Adaptive Quadrupedal Locomotion Using Model Predictive Control With Impedance Control and SINDy Model Enhancement

International Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT Quadrupedal robots operating in unstructured environments require adaptive control systems that can handle diverse terrain conditions without prior surface characterization. This paper presents an integrated control architecture that combines Model Predictive Control (MPC) with adaptive impedance control and SINDy‐based model corrections for ...
Peter James McConnellogue, Mien Van, Rhyss McMullan, Dianhao Zhang, Wasif Naeem   +4 more
wiley   +1 more source

Sliding Motions on Non‐Euclidean State Spaces: A Differential‐Geometric Perspective

International Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT This paper extends sliding‐mode control theory to nonlinear systems evolving on smooth manifolds. Building on differential geometric methods, we reformulate Filippov's notion of solutions, characterize well‐defined vector fields on quotient spaces, and provide a consistent geometric definition of higher‐order sliding modes.
Fernando Castaños
wiley   +1 more source