213 research outputs found
Text-based Editing of Talking-head Video
Editing talking-head video to change the speech content or to remove filler words is challenging. We propose a novel method to edit talking-head video based on its transcript to produce a realistic output video in which the dialogue of the speaker has been modified, while maintaining a seamless audio-visual flow (i.e. no jump cuts). Our method automatically annotates an input talking-head video with phonemes, visemes, 3D face pose and geometry, reflectance, expression and scene illumination per frame. To edit a video, the user has to only edit the transcript, and an optimization strategy then chooses segments of the input corpus as base material. The annotated parameters corresponding to the selected segments are seamlessly stitched together and used to produce an intermediate video representation in which the lower half of the face is rendered with a parametric face model. Finally, a recurrent video generation network transforms this representation to a photorealistic video that matches the edited transcript. We demonstrate a large variety of edits, such as the addition, removal, and alteration of words, as well as convincing language translation and full sentence synthesis
Tiling of the five-fold surface of Al(70)Pd(21)Mn(9)
The nature of the five-fold surface of Al(70)Pd(21)Mn(9) has been
investigated using scanning tunneling microscopy. From high resolution images
of the terraces, a tiling of the surface has been constructed using pentagonal
prototiles. This tiling matches the bulk model of Boudard et. al. (J. Phys.:
Cond. Matter 4, 10149, (1992)), which allows us to elucidate the atomic nature
of the surface. Furthermore, it is consistent with a Penrose tiling T^*((P1)r)
obtained from the geometric model based on the three-dimensional tiling
T^*(2F). The results provide direct confirmation that the five-fold surface of
i-Al-Pd-Mn is a termination of the bulk structure.Comment: 4 pages, 4 figure
Thermodynamical fingerprints of fractal spectra
We investigate the thermodynamics of model systems exhibiting two-scale
fractal spectra. In particular, we present both analytical and numerical
studies on the temperature dependence of the vibrational and electronic
specific heats. For phonons, and for bosons in general, we show that the
average specific heat can be associated to the average (power law) density of
states. The corrections to this average behavior are log-periodic oscillations
which can be traced back to the self-similarity of the spectral staircase. In
the electronic case, even if the thermodynamical quantities exhibit a strong
dependence on the particle number, regularities arise when special cases are
considered. Applications to substitutional and hierarchical structures are
discussed.Comment: 8 latex pages, 9 embedded PS figure
Quasiperiodic Envelope Solitons
We analyse nonlinear wave propagation and cascaded self-focusing due to
second-harmonic generation in Fibbonacci optical superlattices and introduce a
novel concept of nonlinear physics, the quasiperiodic soliton, which describes
spatially localized self-trapping of a quasiperiodic wave. We point out a link
between the quasiperiodic soliton and partially incoherent spatial solitary
waves recently generated experimentally.Comment: Submitted to PRL. 4 pages with 5 figure
Formation of a stable deacagonal quasicrystalline Al-Pd-Mn surface layer
We report the in situ formation of an ordered equilibrium decagonal Al-Pd-Mn
quasicrystal overlayer on the 5-fold symmetric surface of an icosahedral
Al-Pd-Mn monograin. The decagonal structure of the epilayer is evidenced by
x-ray photoelectron diffraction, low-energy electron diffraction and electron
backscatter diffraction. This overlayer is also characterized by a reduced
density of states near the Fermi edge as expected for quasicrystals. This is
the first time that a millimeter-size surface of the stable decagonal Al-Pd-Mn
is obtained, studied and compared to its icosahedral counterpart.Comment: Submitted to Phys. Ref. Lett. (18 July 2001
Self-similarity and novel sample-length-dependence of conductance in quasiperiodic lateral magnetic superlattices
We study the transport of electrons in a Fibonacci magnetic superlattice
produced on a two-dimensional electron gas modulated by parallel magnetic field
stripes arranged in a Fibonacci sequence. Both the transmission coefficient and
conductance exhibit self-similarity and the six-circle property. The presence
of extended states yields a finite conductivity at infinite length, that may be
detected as an abrupt change in the conductance as the Fermi energy is varied,
much as a metal-insulator transition. This is a unique feature of transport in
this new kind of structure, arising from its inherent two-dimensional nature.Comment: 9 pages, 5 figures, revtex, important revisions made. to be published
in Phys. Rev.
Aperiodicity-Induced Second-Order Phase Transition in the 8-State Potts Model
We investigate the critical behavior of the two-dimensional 8-state Potts
model with an aperiodic distribution of the exchange interactions between
nearest-neighbor rows. The model is studied numerically through intensive Monte
Carlo simulations using the Swendsen-Wang cluster algorithm. The transition
point is located through duality relations, and the critical behavior is
investigated using FSS techniques at criticality. For strong enough
fluctuations of the aperiodic sequence under consideration, a second order
phase transition is found. The exponents and are
obtained at the new fixed point.Comment: LaTeX file with Revtex, 4 pages, 5 eps figures, to appear in Phys.
Rev. Let
Crossover between aperiodic and homogeneous semi-infinite critical behaviors in multilayered two-dimensional Ising models
We investigate the surface critical behavior of two-dimensional multilayered
aperiodic Ising models in the extreme anisotropic limit. The system under
consideration is obtained by piling up two types of layers with respectively
and spin rows coupled via nearest neighbor interactions and
, where the succession of layers follows an aperiodic sequence. Far
away from the critical regime, the correlation length is smaller
than the first layer width and the system exhibits the usual behavior of an
ordinary surface transition. In the other limit, in the neighborhood of the
critical point, diverges and the fluctuations are sensitive to the
non-periodic structure of the system so that the critical behavior is governed
by a new fixed point. We determine the critical exponent associated to the
surface magnetization at the aperiodic critical point and show that the
expected crossover between the two regimes is well described by a scaling
function. From numerical calculations, the parallel correlation length
is then found to behave with an anisotropy exponent which
depends on the aperiodic modulation and the layer widths.Comment: LaTeX file, 9 pages, 8 eps figures, to appear in Phys. Rev.
Quantum mechanical relaxation of open quasiperiodic systems
We study the time evolution of the survival probability in open
one-dimensional quasiperiodic tight-binding samples of size , at critical
conditions. We show that it decays algebraically as up
to times , where , and
is the fractal dimension of the spectrum of the closed system. We
verified these results for the Harper model at the metal-insulator transition
and for Fibonacci lattices. Our predictions should be observable in propagation
experiments with electrons or classical waves in quasiperiodic superlattices or
dielectric multilayers.Comment: 4 pages, 5 figure
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