Results 21 to 30 of about 2,659 (132)

Cross‐Entropy of Power Spectral Density Function: A Modal Identification Framework

Earthquake Engineering &Structural Dynamics, EarlyView.
ABSTRACT The power spectral density (PSD) function of measured structural response contains a significant amount of information, including the modal parameters (natural frequencies, damping ratios). Output‐only system identification or modal identification technique can be used for extracting such modal parameters from the measured response or its ...
Su‐Hong Kim, Jae‐Seung Hwang, Dae‐Kun Kwon, Ahsan Kareem   +3 more
wiley   +1 more source

Identifying Peer Effects in Networks with Unobserved Effort and Isolated Students

Journal of Applied Econometrics, EarlyView.
ABSTRACT Peer influence on effort devoted to some activity is often studied when effort is unobserved, and the researcher instead observes an outcome that combines effort with other shocks. For instance, in education, achievement measures such as GPA reflect both effort and idiosyncratic GPA shocks.
Aristide Houndetoungan, Cristelle Kouame, Michael Vlassopoulos   +2 more
wiley   +1 more source

NTECARS: A Nonthermal Equilibrium CARS Spectra Fitting Code

Journal of Raman Spectroscopy, EarlyView.
We present NTECARS, an open‐source code written in Julia for the calculation and fitting of CARS spectra under nonequilibrium conditions. Rovibrational distributions can be flexibly modeled and fitted for different use cases. The code currently implements CO2$$ \mathrm{C}{\mathrm{O}}_2 $$ and N2$$ {\mathrm{N}}_2 $$ molecules and is validated under ...
Christian A. Busch, Uwe Czarnetzki
wiley   +1 more source

Resonant States Reveal Strong Light–Matter Coupling in Nanophotonic Cavities

Laser &Photonics Reviews, EarlyView.
Photonic resonant states reveal characteristics of coupled light–matter systems that would otherwise be hidden by damping. Their trajectories (when tuning the optical resonance) undergo a qualitative change at the onset of strong coupling: They start swapping positions.
Jan David Fischbach, Sergei Gladyshev, Adrià Canós Valero, Markus Nyman, Thomas Weiss, Carsten Rockstuhl   +5 more
wiley   +1 more source

Revealing the Resonant Physics of Open Photonic Time Crystals

Laser &Photonics Reviews, EarlyView.
ABSTRACT Photonic time crystals (PTCs) are media whose permittivity is modulated periodically in time, enabling momentum bandgaps and parametric amplification of light. Their realization at the nanoscale can revolutionize the study of light‐matter interactions.
Adrià Canós Valero, Sergei Gladyshev, David Globosits, Stefan Rotter, Egor A. Muljarov, Thomas Weiss   +5 more
wiley   +1 more source

Theory of Supercritical Coupling and Generalized Bound States in the Continuum

Laser &Photonics Reviews, EarlyView.
We develop a general theory of supercritical coupling and generalized bound states in the continuum (gBICs), revealing how interference between radiative and absorptive channels enables quality factors beyond conventional material‐loss limits. The framework unifies non‐Hermitian mode coupling, causality‐driven reactive interactions, and interference ...
Sergio Balestrieri, Bruno Miranda, Silvia Romano, Gianluigi Zito   +3 more
wiley   +1 more source

Group‐Patch Joint Compression: Compressing Dynamic B0 and Static RF Spatial Modulations Across k‐Space Subregion Groups for Highly Accelerated MRI

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To accelerate MRI further, rapid B0 field modulations can be applied during oversampled readout to capture additional physical information, as in Wave‐CAIPI/FRONSAC/local B0 coils modulation techniques. These methods, however, turn the Fourier readout into a non‐Fourier‐encoded dimension that cannot be reconstructed by FFT, posing ...
Rui Tian, Klaus Scheffler
wiley   +1 more source

Fault Detection of Electric Motors via Symmetrized Dot Pattern‐Based Features

International Journal of Mechanical System Dynamics, EarlyView.
ABSTRACT This study proposes a novel symmetrized dot pattern (SDP) approach using designed SDP‐based features, extracted from transformed vibration signals, for fault detection. These features describe the compactness, inclination, and shape of the “snowflake” diagram distributions.
Mario Spirto, Pierangelo Malfi, Armando Nicolella, Francesco Melluso, Chiara Cosenza, Sergio Savino, Vincenzo Niola   +6 more
wiley   +1 more source

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

Propagation of internal gravity waves: Optimal vertical discretisation and grid design based on numerical error analysis

Quarterly Journal of the Royal Meteorological Society, EarlyView.
An energy‐conserving discrete framework for the vertical discretisation of stratified ocean models is developed using internal gravity‐wave theory. A β$$ \beta $$‐indexed family of schemes is analysed through perturbation theory, revealing optimal parameter choices and grid designs that reduce truncation errors significantly.
Gabriel Derrida, Laurent Debreu, Florian Lemarié, Jérome Chanut   +3 more
wiley   +1 more source