6,053 research outputs found
Design of of model-based controllers via parametric programming
Imperial Users onl
Nonautonomous Hamiltonians
We present a theory of resonances for a class of non-autonomous Hamiltonians
to treat the structural instability of spatially localized and time-periodic
solutions associated with an unperturbed autonomous Hamiltonian.
The mechanism of instability is radiative decay, due to resonant coupling of
the discrete modes to the continuum modes by the time-dependent perturbation.
This results in a slow transfer of energy from the discrete modes to the
continuum. The rate of decay of solutions is slow and hence the decaying bound
states can be viewed as metastable. The ideas are closely related to the
authors' work on (i) a time dependent approach to the instability of
eigenvalues embedded in the continuous spectra, and (ii) resonances, radiation
damping and instability in Hamiltonian nonlinear wave equations. The theory is
applied to a general class of Schr\"odinger equations. The phenomenon of
ionization may be viewed as a resonance problem of the type we consider and we
apply our theory to find the rate of ionization, spectral line shift and local
decay estimates for such Hamiltonians.Comment: To appear in Journal of Statistical Physic
Statistical modelling of algorithms for signal processing in systems based on environment perception
One cornerstone for realising automated driving systems is an appropriate handling of uncertainties in the environment perception and situation interpretation. Uncertainties arise due to noisy sensor measurements or the unknown future evolution of a traffic situation. This work contributes to the understanding of these uncertainties by modelling and propagating them with parametric probability distributions
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