1,589 research outputs found
Experiences with a simplified microsimulation for the Dallas/Fort Worth area
We describe a simple framework for micro simulation of city traffic. A medium
sized excerpt of Dallas was used to examine different levels of simulation
fidelity of a cellular automaton method for the traffic flow simulation and a
simple intersection model. We point out problems arising with the granular
structure of the underlying rules of motion.Comment: accepted by Int.J.Mod.Phys.C, 20 pages, 14 figure
The dynamics of iterated transportation simulations
Iterating between a router and a traffic micro-simulation is an increasibly
accepted method for doing traffic assignment. This paper, after pointing out
that the analytical theory of simulation-based assignment to-date is
insufficient for some practical cases, presents results of simulation studies
from a real world study. Specifically, we look into the issues of uniqueness,
variability, and robustness and validation. Regarding uniqueness, despite some
cautionary notes from a theoretical point of view, we find no indication of
``meta-stable'' states for the iterations. Variability however is considerable.
By variability we mean the variation of the simulation of a given plan set by
just changing the random seed. We show then results from three different
micro-simulations under the same iteration scenario in order to test for the
robustness of the results under different implementations. We find the results
encouraging, also when comparing to reality and with a traditional assignment
result.
Keywords: dynamic traffic assignment (DTA); traffic micro-simulation;
TRANSIMS; large-scale simulations; urban planningComment: 24 pages, 7 figure
Ohio\u27s New Partnership Law
This article focuses on key areas where Chapter 1776 and RUPA reflect changes in the law of partnerships. This article also highlights how Chapter 1776 differs from RUPA so that lawyers can tailor agreements to Ohio law, and lawyers and courts considering questions of Ohio partnership law can take into account statutory variations when considering the persuasiveness of case law from other jurisdictions that may not have the same statutory rules
Ohio\u27s New Partnership Law
This article focuses on key areas where Chapter 1776 and RUPA reflect changes in the law of partnerships. This article also highlights how Chapter 1776 differs from RUPA so that lawyers can tailor agreements to Ohio law, and lawyers and courts considering questions of Ohio partnership law can take into account statutory variations when considering the persuasiveness of case law from other jurisdictions that may not have the same statutory rules
Two Lane Traffic Simulations using Cellular Automata
We examine a simple two lane cellular automaton based upon the single lane CA
introduced by Nagel and Schreckenberg. We point out important parameters
defining the shape of the fundamental diagram. Moreover we investigate the
importance of stochastic elements with respect to real life traffic.Comment: to be published in Physica A, 19 pages, 9 out of 13 postscript
figures, 24kB in format .tar.gz., 33kB in format .tar.gz.uu, for a full
version including all figures see
http://studguppy.tsasa.lanl.gov/research_team/papers
A Cellular Automaton Model for Bi-Directionnal Traffic
We investigate a cellular automaton (CA) model of traffic on a bi-directional
two-lane road. Our model is an extension of the one-lane CA model of {Nagel and
Schreckenberg 1992}, modified to account for interactions mediated by passing,
and for a distribution of vehicle speeds. We chose values for the various
parameters to approximate the behavior of real traffic. The density-flow
diagram for the bi-directional model is compared to that of a one-lane model,
showing the interaction of the two lanes. Results were also compared to
experimental data, showing close agreement. This model helps bridge the gap
between simplified cellular automata models and the complexity of real-world
traffic.Comment: 4 pages 6 figures. Accepted Phys Rev
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Neuronal SIRT1 Regulates Metabolic and Reproductive Function and the Response to Caloric Restriction.
Sirt1 is an NAD-dependent, class III deacetylase that functions as a cellular energy sensor. In addition to its well-characterized effects in peripheral tissues, emerging evidence suggests that neuronal Sirt1 activity plays a role in the central regulation of energy balance and glucose metabolism. In this study, we generated mice expressing an enzymatically inactive form (N-MUT) or wild-type (WT) SIRT1 (N-OX) in mature neurons. N-OX male and female mice had impaired glucose tolerance, and N-MUT female, but not male, mice had improved glucose tolerance compared with that of WT littermates. Furthermore, glucose tolerance was improved in all mice with caloric restriction (CR) but was greater in the N-OX mice, who had better glucose tolerance than their littermates. At the reproductive level, N-OX females had impaired estrous cycles, with increased cycle length and more time in estrus. LH and progesterone surges were absent on the evening of proestrus in the N-OX mice, suggesting a defect in spontaneous ovulation, which was confirmed by the ovarian histology revealing fewer corpora lutea. Despite this defect, the mice were still fertile when mated to WT mice on the day of proestrus, indicating that the mice could respond to normal pheromonal or environmental cues. When subjected to CR, the N-OX mice went into diestrus arrest earlier than their littermates. Together, these results suggested that the overexpression of SIRT1 rendered the mice more sensitive to the metabolic improvements and suppression of reproductive cycles by CR, which was independent of circadian rhythms
A Simplified Cellular Automaton Model for City Traffic
We systematically investigate the effect of blockage sites in a cellular
automaton model for traffic flow. Different scheduling schemes for the blockage
sites are considered. None of them returns a linear relationship between the
fraction of ``green'' time and the throughput. We use this information for a
fast implementation of traffic in Dallas.Comment: 12 pages, 18 figures. submitted to Phys Rev
Bulk and Surface Nucleation Processes in Ag2S Conductance Switches
We studied metallic Ag formation inside and on the surface of Ag2S thin
films, induced by the electric field created with a STM tip. Two clear regimes
were observed: cluster formation on the surface at low bias voltages, and full
conductance switching at higher bias voltages (V > 70mV). The bias voltage at
which this transition is observed is in agreement with the known threshold
voltage for conductance switching at room temperature. We propose a model for
the cluster formation at low bias voltage. Scaling of the measured data with
the proposed model indicates that the process takes place near steady state,
but depends on the STM tip geometry. The growth of the clusters is confirmed by
tip retraction measurements and topography scans. This study provides improved
understanding of the physical mechanisms that drive conductance switching in
solid electrolyte memristive devices.Comment: In press for PR
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