1,322 research outputs found
Versatile surrogate models for IC buffers
In previous papers [1,2] the authors have investigated the use of Volterra series in the identification of IC buffer macro-models. While the approach benefited from some of the inherent qualities of Volterra series it preserved the two-state paradigm of earlier methods (see [3] and its references) and was thus limited in its versatility. In the current paper the authors tackle the challenge of going beyond an application or device-oriented approach and build versatile surrogate models that mimic the behavior of IC buffers over a wide frequency band and for a variety of loads thus achieving an unprecedented degree of generality. This requires the use of a more general system identification paradig
Continuum limit of amorphous elastic bodies (III): Three dimensional systems
Extending recent numerical studies on two dimensional amorphous bodies, we
characterize the approach of elastic continuum limit in three dimensional
(weakly polydisperse) Lennard-Jones systems. While performing a systematic
finite-size analysis (for two different quench protocols) we investigate the
non-affine displacement field under external strain, the linear response to an
external delta force and the low-frequency harmonic eigenmodes and their
density distribution. Qualitatively similar behavior is found as in two
dimensions. We demonstrate that the classical elasticity description breaks
down below an intermediate length scale , which in our system is
approximately 23 molecular sizes. This length characterizes the correlations of
the non-affine displacement field, the self-averaging of external noise with
distance from the source and gives the lower wave length bound for the
applicability of the classical eigenfrequency calculations. We trace back the
"Boson-peak" of the density of eigenfrequencies (obtained from the velocity
auto-correlation function) to the inhomogeneities on wave lengths smaller than
.Comment: 27 pages, 11 figures, submitted to Phys. Rev.
A Stochastic Description for Extremal Dynamics
We show that extremal dynamics is very well modelled by the "Linear
Fractional Stable Motion" (LFSM), a stochastic process entirely defined by two
exponents that take into account spatio-temporal correlations in the
distribution of active sites. We demonstrate this numerically and analytically
using well-known properties of the LFSM. Further, we use this correspondence to
write an exact expressions for an n-point correlation function as well as an
equation of fractional order for interface growth in extremal dynamics.Comment: 4 pages LaTex, 3 figures .ep
Storage Device Sizing for a Hybrid Railway Traction System by Means of Bicausal Bond Graphs
In this paper, the application of bicausal bond graphs for system design in electrical engineering is emphasized. In particular, it is shown how this approach is very useful for model inversion and parameter dimensioning. To illustrate these issues, a hybrid railway traction device is considered as a case study. The synthesis of a storage device (a supercapacitor) included in this system is then discussed
Inhomogeneous elastic response of silica glass
Using large scale molecular dynamics simulations we investigate the
properties of the {\em non-affine} displacement field induced by macroscopic
uniaxial deformation of amorphous silica,a strong glass according to Angell's
classification. We demonstrate the existence of a length scale
characterizing the correlations of this field (corresponding to a volume of
about 1000 atoms), and compare its structure to the one observed in a standard
fragile model glass. The "Boson-peak'' anomaly of the density of states can be
traced back in both cases to elastic inhomogeneities on wavelengths smaller
than , where classical continuum elasticity becomes simply unapplicable
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