5,029 research outputs found
A Durbin-Watson serial correlation test for ARX processes via excited adaptive tracking
We propose a new statistical test for the residual autocorrelation in ARX
adaptive tracking. The introduction of a persistent excitation in the adaptive
tracking control allows us to build a bilateral statistical test based on the
well-known Durbin-Watson statistic. We establish the almost sure convergence
and the asymptotic normality for the Durbin-Watson statistic leading to a
powerful serial correlation test. Numerical experiments illustrate the good
performances of our statistical test procedure
Probing the sheath electric field with a crystal lattice by using thermophoresis in dusty plasma
A two-dimensional dust crystal levitated in the sheath of a modified Gaseous
Electronics Conference (GEC) reference cell is manipulated by heating or
cooling the lower electrode. The dust charge is obtained by measuring global
characteristics of the levitated crystal obtained from top-view pictures. From
the force balance, the electric field in the sheath is reconstructed. From the
Bohm criterion, we conclude that the dust crystal is levitated mainly above and
just below the classical Bohm point
Improving Software Reliability Forecasting
This work investigates some methods for software reliability forecasting. A supermodel is presented as a suited tool for prediction of reliability in software project development. Also, times series forecasting for cumulative interfailure time is proposed and illustrated
Deformations of vector-scalar models
Abelian vector fields non-minimally coupled to uncharged scalar fields arise
in many contexts. We investigate here through algebraic methods their
consistent deformations ("gaugings"), i.e., the deformations that preserve the
number (but not necessarily the form or the algebra) of the gauge symmetries.
Infinitesimal consistent deformations are given by the BRST cohomology classes
at ghost number zero. We parametrize explicitly these classes in terms of
various types of global symmetries and corresponding Noether currents through
the characteristic cohomology related to antifields and equations of motion.
The analysis applies to all ghost numbers and not just ghost number zero. We
also provide a systematic discussion of the linear and quadratic constraints on
these parameters that follow from higher-order consistency. Our work is
relevant to the gaugings of extended supergravities.Comment: v2: references added, typos corrected, minor changes for clarit
The Rose and the Heart
https://digitalcommons.library.umaine.edu/mmb-vp/6142/thumbnail.jp
Random barrier double-well model for resistive switching in tunnel barriers
The resistive switching phenomenon in MgO-based tunnel junctions is
attributed to the effect of charged defects inside the barrier. The presence of
electron traps in the MgO barrier, that can be filled and emptied, locally
modifies the conductance of the barrier and leads to the resistive switching
effects. A double-well model for trapped electrons in MgO is introduced to
theoretically describe this phenomenon. Including the statistical distribution
of potential barrier heights for these traps leads to a power-law dependence of
the resistance as a function of time, under a constant bias voltage. This model
also predicts a power-law relation of the hysteresis as a function of the
voltage sweep frequency. Experimental transport results strongly support this
model and in particular confirm the expected power laws dependencies of
resistance. They moreover indicate that the exponent of these power laws varies
with temperature as theoretically predicted.Comment: 18 pages, 5 figures, final versio
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