2,376 research outputs found
Winning strategies in congested traffic
One-directional traffic on two-lanes is modeled in the framework of a
spring-block type model. A fraction of the cars are allowed to change
lanes, following simple dynamical rules, while the other cars keep their
initial lane. The advance of cars, starting from equivalent positions and
following the two driving strategies is studied and compared. As a function of
the parameter the winning probability and the average gain in the
advancement for the lane-changing strategy is computed. An interesting
phase-transition like behavior is revealed and conclusions are drawn regarding
the conditions when the lane changing strategy is the better option for the
drivers.Comment: 5 pages, 5 figure
Intransitivity and coexistence in four species cyclic games
Intransitivity is a property of connected, oriented graphs representing
species interactions that may drive their coexistence even in the presence of
competition, the standard example being the three species Rock-Paper-Scissors
game. We consider here a generalization with four species, the minimum number
of species allowing other interactions beyond the single loop (one predator,
one prey). We show that, contrary to the mean field prediction, on a square
lattice the model presents a transition, as the parameter setting the rate at
which one species invades another changes, from a coexistence to a state in
which one species gets extinct. Such a dependence on the invasion rates shows
that the interaction graph structure alone is not enough to predict the outcome
of such models. In addition, different invasion rates permit to tune the level
of transitiveness, indicating that for the coexistence of all species to
persist, there must be a minimum amount of intransitivity.Comment: Final, published versio
Is Quantum Mechanics Compatible with a Deterministic Universe? Two Interpretations of Quantum Probabilities
Two problems will be considered: the question of hidden parameters and the
problem of Kolmogorovity of quantum probabilities. Both of them will be
analyzed from the point of view of two distinct understandings of quantum
mechanical probabilities. Our analysis will be focused, as a particular
example, on the Aspect-type EPR experiment. It will be shown that the quantum
mechanical probabilities appearing in this experiment can be consistently
understood as conditional probabilities without any paradoxical consequences.
Therefore, nothing implies in the Aspect experiment that quantum theory is
incompatible with a deterministic universe.Comment: REVISED VERSION! ONLY SMALL CHANGES IN THE TEXT! compressed and
uuencoded postscript, a uuencoded version of a demo program file (epr.exe for
DOS) is attached as a "Figure
Spring-block model for a single-lane highway traffic
A simple one-dimensional spring-block chain with asymmetric interactions is
considered to model an idealized single-lane highway traffic. The main elements
of the system are blocks (modeling cars), springs with unidirectional
interactions (modeling distance keeping interactions between neighbors), static
and kinetic friction (modeling inertia of drivers and cars) and spatiotemporal
disorder in the values of these friction forces (modeling differences in the
driving attitudes). The traveling chain of cars correspond to the dragged
spring-block system. Our statistical analysis for the spring-block chain
predicts a non-trivial and rich complex behavior. As a function of the disorder
level in the system a dynamic phase-transition is observed. For low disorder
levels uncorrelated slidings of blocks are revealed while for high disorder
levels correlated avalanches dominates.Comment: 6 pages, 7 figure
Benefits of a marketing cooperative in transition agriculture: Mórakert purchasing and service co-operative
The paper analyses the potential benefits of marketing cooperatives in Hungary, employing a transaction cost economics framework. We found that the purchased quantity, the existence of contracts, flexibility and trust are the most important factors farmers consider when selling their products via a cooperative. The most striking result is that diversification has positive influences on the share of cooperatives in farmers’ sale. Furthermore, farmers with larger bargaining power have less willingness to sell their product to the cooperative. Surprisingly, asset specificity has rather negative effects on the share of cooperatives in members’ sales
Nonlinear asteroseismology of RR Lyrae
The observations of the Kepler space telescope revealed that fundamental-mode
RR Lyrae stars may show various radial overtones. The presence of multiple
radial modes may allow us to conduct nonlinear asteroseismology: comparison of
mode amplitudes and frequency shifts between observations and models. Here we
report the detection of three radial modes in the star RR Lyr, the eponym of
the class, using the Kepler short cadence data: besides the fundamental mode,
both the first and the ninth overtones can be derived from the data set. RR
Lyrae shows period doubling, but switches occasionally to a state where a
pattern of six pulsation cycles repeats instead of two. We found hydrodynamic
models that show the same three modes and the period-six state, allowing for
comparison with the observations.Comment: 5 pages, 4 figures, accepted for publication in ApJ Letter
Semiclassical description of the kinematically complete experiments
Based on the semiclassical, impact parameter method a theoretical model is
constructed to calculate totally differential cross sections for single
ionization of helium by impact with fast C ions. Good agreement with the
experiment is achieved in the scattering plane, while in the perpendicular
plane a similar structure to that observed experimentally is obtained. The
contribution of different partial waves to the cross section is also
investigated.Comment: 9 pages, 6 figure
Semiclassical model for calculating fully differential ionization cross sections of the H molecule
Fully differential cross sections are calculated for the ionization of H
by fast charged projectiles using a semiclassical model developed previously
for the ionization of atoms. The method is tested in case of 4 keV electron and
6 MeV proton projectiles. The obtained results show good agreement with the
available experimental data. Interference effects due to the two-center
character of the target are also observed and analyzed.Comment: 11 pages, 4 figure
An IMEX scheme combined with Richardson extrapolation methods for some reaction-diffusion equations
An implicit-explicit (IMEX) method is combined with some so-called Richardson extrapolation (RiEx) methods for the numerical solution of reaction-diffusion equations with pure Neumann boundary conditions. The results are applied to a model for determining the overpotential in a Proton Exchange Membrane (PEM) fuel cell
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