5,050 research outputs found
Fuzzy Logic Control of Adaptive ARQ for Video Distribution over a Bluetooth Wireless Link
Bluetooth's default automatic repeat request (ARQ) scheme is not suited to video distribution resulting in missed display and decoded deadlines. Adaptive ARQ with active discard of expired packets from the send buffer is an alternative approach. However, even with the addition of cross-layer adaptation to picture-type packet importance, ARQ is not ideal in conditions of a deteriorating RF channel. The paper presents fuzzy logic control of ARQ, based on send buffer fullness and the head-of-line packet's deadline. The advantage of the fuzzy logic approach, which also scales its output according to picture type importance, is that the impact of delay can be directly introduced to the model, causing retransmissions to be reduced compared to all other schemes. The scheme considers both the delay constraints of the video stream and at the same time avoids send buffer overflow. Tests explore a variety of Bluetooth send buffer sizes and channel conditions. For adverse channel conditions and buffer size, the tests show an improvement of at least 4 dB in video quality compared to nonfuzzy schemes. The scheme can be applied to any codec with I-, P-, and (possibly) B-slices by inspection of packet headers without the need for encoder intervention.</jats:p
Power-Constrained Fuzzy Logic Control of Video Streaming over a Wireless Interconnect
Wireless communication of video, with Bluetooth as an example, represents a compromise between channel conditions, display and decode deadlines, and energy constraints. This paper proposes fuzzy logic control (FLC) of automatic repeat request (ARQ) as a way of reconciling these factors, with a 40% saving in power in the worst channel conditions from economizing on transmissions when channel errors occur. Whatever the channel conditions are, FLC is shown to outperform the default Bluetooth scheme and an alternative Bluetooth-adaptive ARQ scheme in terms of reduced packet loss and delay, as well as improved video quality
Local Fractional Supersymmetry for Alternative Statistics
A group theory justification of one dimensional fractional supersymmetry is
proposed using an analogue of a coset space, just like the one introduced in
supersymmetry. This theory is then gauged to obtain a local fractional
supersymmetry {\it i.e.} a fractional supergravity which is then quantized {\it
\`a la Dirac} to obtain an equation of motion for a particle which is in a
representation of the braid group and should describe alternative statistics. A
formulation invariant under general reparametrization is given, by means of a
curved fractional superline.Comment: 15 pages, latex, no figur
Fractional Supersymmetry and Fth-Roots of Representations
A generalization of super-Lie algebras is presented. It is then shown that
all known examples of fractional supersymmetry can be understood in this
formulation. However, the incorporation of three dimensional fractional
supersymmetry in this framework needs some care. The proposed solutions lead
naturally to a formulation of a fractional supersymmetry starting from any
representation D of any Lie algebra g. This involves taking the Fth-roots of D
in an appropriate sense. A fractional supersymmetry in any space-time dimension
is then possible. This formalism finally leads to an infinite dimensional
extension of g, reducing to the centerless Virasoro algebra when g=sl(2,R).Comment: 23 pages, 1 figure, LaTex file with epsf.st
A numerical finite size scaling approach to many-body localization
We develop a numerical technique to study Anderson localization in
interacting electronic systems. The ground state of the disordered system is
calculated with quantum Monte-Carlo simulations while the localization
properties are extracted from the ``Thouless conductance'' , i.e. the
curvature of the energy with respect to an Aharonov-Bohm flux. We apply our
method to polarized electrons in a two dimensional system of size . We
recover the well known universal one
parameter scaling function without interaction. Upon switching on the
interaction, we find that is unchanged while the system flows toward
the insulating limit. We conclude that polarized electrons in two dimensions
stay in an insulating state in the presence of weak to moderate
electron-electron correlations.Comment: 5 pages, 4 figure
A model of gravitation with global U(1)-symmetry
It is shown that an embedding of the general relativity space into a flat
space gives a model of gravitation with the global symmetry and the
discrete one. The last one may be transformed into the symmetry
of the unified model, and the demand of independence of and
transformations leads to the estimate where
is an analog of the Weinberg angle of the standard model.Comment: 7 page
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