227 research outputs found
Long-term power-law fluctuation in Internet traffic
Power-law fluctuation in observed Internet packet flow are discussed. The
data is obtained by a multi router traffic grapher (MRTG) system for 9 months.
The internet packet flow is analyzed using the detrended fluctuation analysis.
By extracting the average daily trend, the data shows clear power-law
fluctuations. The exponents of the fluctuation for the incoming and outgoing
flow are almost unity. Internet traffic can be understood as a daily periodic
flow with power-law fluctuations.Comment: 10 pages, 8 figure
Finite automata with advice tapes
We define a model of advised computation by finite automata where the advice
is provided on a separate tape. We consider several variants of the model where
the advice is deterministic or randomized, the input tape head is allowed
real-time, one-way, or two-way access, and the automaton is classical or
quantum. We prove several separation results among these variants, demonstrate
an infinite hierarchy of language classes recognized by automata with
increasing advice lengths, and establish the relationships between this and the
previously studied ways of providing advice to finite automata.Comment: Corrected typo
Temperature inversion symmetry in the Casimir effect with an antiperiodic boundary condition
We present explicitly another example of a temperature inversion symmetry in
the Casimir effect for a nonsymmetric boundary condition. We also give an
interpretation for our result.Comment: 4 page
Multi-State Image Restoration by Transmission of Bit-Decomposed Data
We report on the restoration of gray-scale image when it is decomposed into a
binary form before transmission. We assume that a gray-scale image expressed by
a set of Q-Ising spins is first decomposed into an expression using Ising
(binary) spins by means of the threshold division, namely, we produce (Q-1)
binary Ising spins from a Q-Ising spin by the function F(\sigma_i - m) = 1 if
the input data \sigma_i \in {0,.....,Q-1} is \sigma_i \geq m and 0 otherwise,
where m \in {1,....,Q-1} is the threshold value. The effects of noise are
different from the case where the raw Q-Ising values are sent. We investigate
which is more effective to use the binary data for transmission or to send the
raw Q-Ising values. By using the mean-field model, we first analyze the
performance of our method quantitatively. Then we obtain the static and
dynamical properties of restoration using the bit-decomposed data. In order to
investigate what kind of original picture is efficiently restored by our
method, the standard image in two dimensions is simulated by the mean-field
annealing, and we compare the performance of our method with that using the
Q-Ising form. We show that our method is more efficient than the one using the
Q-Ising form when the original picture has large parts in which the nearest
neighboring pixels take close values.Comment: latex 24 pages using REVTEX, 10 figures, 4 table
Hadamard States and Adiabatic Vacua
Reversing a slight detrimental effect of the mailer related to TeXabilityComment: 10pages, LaTeX (RevTeX-preprint style
Magnetic von-Neumann lattice for two-dimensional electrons in the magnetic field
One-particle eigenstates and eigenvalues of two-dimensional electrons in the
strong magnetic field with short range impurity and impurities, cosine
potential, boundary potential, and periodic array of short range potentials are
obtained by magnetic von-Neumann lattice in which Landau level wave functions
have minimum spatial extensions. We find that there is a dual correspondence
between cosine potential and lattice kinetic term and that the representation
based on the von-Neumann lattice is quite useful for solving the system's
dynamics.Comment: 21pages, figures not included, EPHOU-94-00
Self-organization of traffic jams in cities: effects of stochastic dynamics and signal periods
We propose a cellular automata model for vehicular traffic in cities by
combining (and appropriately modifying) ideas borrowed from the
Biham-Middleton-Levine (BML) model of city traffic and the Nagel-Schreckenberg
(NS) model of highway traffic. We demonstrate a phase transition from the
"free-flowing" dynamical phase to the completely "jammed" phase at a vehicle
density which depends on the time periods of the synchronized signals and the
separation between them. The intrinsic stochasticity of the dynamics, which
triggers the onset of jamming, is similar to that in the NS model, while the
phenomenon of complete jamming through self-organization as well as the final
jammed configurations are similar to those in the BML model. Using our new
model, we have made an investigation of the time-dependence of the average
speeds of the cars in the "free-flowing" phase as well as the dependence of
flux and jamming on the time period of the signals.Comment: 4 pages, REVTEX, 4 eps figures include
Calibration of the Particle Density in Cellular-Automaton Models for Traffic Flow
We introduce density dependence of the cell size in cellular-automaton models
for traffic flow, which allows a more precise correspondence between real-world
phenomena and what observed in simulation. Also, we give an explicit
calibration of the particle density particularly for the asymmetric simple
exclusion process with some update rules. We thus find that the present method
is valid in that it reproduces a realistic flow-density diagram.Comment: 2 pages, 2 figure
Correlation between star formation activity and electron density of ionized gas at z=2.5
In the redshift interval of , the physical conditions of the
inter-stellar medium (ISM) in star-forming galaxies are likely to be different
from those in the local Universe because of lower gaseous metallicities, higher
gas fractions, and higher star formation activities. In fact, observations
suggest that higher electron densities, higher ionization parameters, and
harder UV radiation fields are common. In this paper, based on the spectra of
H-selected star-forming galaxies at taken with Multi-Object
Spectrometer for InfraRed Exploration (MOSFIRE) on Keck-1 telescope, we measure
electron densities () using the oxygen line ratio (
[OII]3726,3729), and investigate the relationships between the
electron density of ionized gas and other physical properties. As a result, we
find that the specific star formation rate (sSFR) and the surface density of
SFR () are correlated with the electron density at
for the first time. The relation is likely to be
linked to the star formation law in HII regions (where star formation activity
is regulated by interstellar pressure). Moreover, we discuss the mode of star
formation in those galaxies. The correlation between sSFR and
suggests that highly star-forming galaxies (with high
sSFR) tend to be characterized by higher surface densities of star formation
() and thus higher values as well.Comment: 7 pages, 1 table, 4 figures, title is changed, accepted to MNRA
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