5,374 research outputs found
Homesick L\'evy walk: A mobility model having Ichi-go Ichi-e and scale-free properties of human encounters
In recent years, mobility models have been reconsidered based on findings by
analyzing some big datasets collected by GPS sensors, cellphone call records,
and Geotagging. To understand the fundamental statistical properties of the
frequency of serendipitous human encounters, we conducted experiments to
collect long-term data on human contact using short-range wireless
communication devices which many people frequently carry in daily life. By
analyzing the data we showed that the majority of human encounters occur
once-in-an-experimental-period: they are Ichi-go Ichi-e. We also found that the
remaining more frequent encounters obey a power-law distribution: they are
scale-free. To theoretically find the origin of these properties, we introduced
as a minimal human mobility model, Homesick L\'evy walk, where the walker
stochastically selects moving long distances as well as L\'evy walk or
returning back home. Using numerical simulations and a simple mean-field
theory, we offer a theoretical explanation for the properties to validate the
mobility model. The proposed model is helpful for evaluating long-term
performance of routing protocols in delay tolerant networks and mobile
opportunistic networks better since some utility-based protocols select nodes
with frequent encounters for message transfer.Comment: 8 pages, 10 figure
Influence of QED Corrections on the Orientation of Chiral Symmetry Breaking in the NJL model
We study QED corrections to chiral symmetry breaking in the
Nambu--Jona-Lasinio (NJL) model with two flavors of quarks. In this model, the
isospin symmetry is broken by the differences between the current quark masses
and the electromagnetic charges of the up and down quarks. To leading order in
the 1/N expansion, we calculate the effective potential of the model with
one-loop QED corrections at finite temperature.
Evaluating the effective potential, we study the influence of the isospin
symmetry breaking on the orientation of chiral symmetry breaking.
The current quark mass plays an essential role in maintaining the orientation
of the chiral symmetry breaking.
If the average of the up and down quark masses is small enough, we find a
phase in which the pion field has non-vanishing expectation value and dynamical
CP violation takes place.Comment: 22 pages, 13 figures; added discussion about pion mass differenc
Phase structure of NJL model with finite quark mass and QED correction
We study QED corrections to the chiral symmetry breaking in
Nambu-Jona-Lasinio (NJL) model with two flavors of quarks. In the model the
isospin symmetry is broken by differences of the current quark masses and the
electromagnetic charges between up and down quarks. In the leading order of the
1/N expansion we calculate the effective potential of the model with one-loop
QED corrections. Evaluating the effective potential, we study an influence of
the isospin symmetry breaking on the orientation of chiral symmetry breaking.
The current quark mass has an important contribution for the orientation of
chiral symmetry breaking.Comment: 7 pages, 8 figures, To appear in the proceedings of the Workshop on
Origin of Mass and Strong Coupling Gauge Theories, Nagoya, Japan, 21-24
November 200
Similarity and Probability Distribution Functions in Many-body Stochastic Processes with Multiplicative Interactions
Analytical and numerical studies on many-body stochastic processes with
multiplicative interactions are reviewed. The method of moment relations is
used to investigate effects of asymmetry and randomness in interactions.
Probability distribution functions of the processes generally have similarity
solutions with power-law tails. Growth rates of the system and power-law
exponents of the tails are determined via transcendental equations. Good
agreement is achieved between analytical calculations and Monte Carlo
simulations.Comment: 8 pages, 4 figures, CN-Kyoto proceeding
INSTRUMENTATION-BASED MUSIC SIMILARITY USING SPARSE REPRESENTATIONS
© 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works
- …