11,518 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
Effective-Lagrangian approach to gamma gamma --> WW; II: Results and comparison with e+e- --> WW
We present a study of anomalous electroweak gauge-boson couplings which can
be measured in e+e- and gamma gamma collisions at a future linear collider like
ILC. We consider the gauge-boson sector of a locally SU(2) x U(1) invariant
effective Lagrangian with ten dimension-six operators added to the Lagrangian
of the Standard Model. These operators induce anomalous three- and
four-gauge-boson couplings and an anomalous gamma gamma H coupling. We
calculate the reachable sensitivity for the measurement of the anomalous
couplings in gamma gamma --> WW. We compare these results with the reachable
precision in the reaction e+e- --> WW on the one hand and with the bounds that
one can get from high-precision observables in Z decays on the other hand. We
show that one needs both the e+e- and the gamma gamma modes at an ILC to
constrain the largest possible number of anomalous couplings and that the
Giga-Z mode offers the best sensitivity for certain anomalous couplings.Comment: 25 pages, 1 figure, 7 tables, comments, references and a table added;
to appear in EPJ
Software reliability: Repetitive run experimentation and modeling
A software experiment conducted with repetitive run sampling is reported. Independently generated input data was used to verify that interfailure times are very nearly exponentially distributed and to obtain good estimates of the failure rates of individual errors and demonstrate how widely they vary. This fact invalidates many of the popular software reliability models now in use. The log failure rate of interfailure time was nearly linear as a function of the number of errors corrected. A new model of software reliability is proposed that incorporates these observations
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
Stability and Symmetry Breaking in the General Two-Higgs-Doublet Model
A method is presented for the analysis of the scalar potential in the general
Two-Higgs-Doublet Model. This allows us to give the conditions for the
stability of the potential and for electroweak symmetry breaking in this model
in a very concise way. These results are then applied to two different Higgs
potentials in the literature, namely the MSSM and the Two-Higgs-Doublet
potential proposed by Gunion at al. All known results for these models follow
easily as special cases from the general results. In particular, in the
potential of Gunion et al. we can clarify some interesting aspects of the model
with the help of the proposed method.Comment: 20 pages, 3 figures, extended version, typos corrected, references
adde
Software reliability: Additional investigations into modeling with replicated experiments
The effects of programmer experience level, different program usage distributions, and programming languages are explored. All these factors affect performance, and some tentative relational hypotheses are presented. An analytic framework for replicated and non-replicated (traditional) software experiments is presented. A method of obtaining an upper bound on the error rate of the next error is proposed. The method was validated empirically by comparing forecasts with actual data. In all 14 cases the bound exceeded the observed parameter, albeit somewhat conservatively. Two other forecasting methods are proposed and compared to observed results. Although demonstrated relative to this framework that stages are neither independent nor exponentially distributed, empirical estimates show that the exponential assumption is nearly valid for all but the extreme tails of the distribution. Except for the dependence in the stage probabilities, Cox's model approximates to a degree what is being observed
Solitons in the one-dimensional forest fire model
Fires in the one-dimensional Bak-Chen-Tang forest fire model propagate as
solitons, resembling shocks in Burgers turbulence. The branching of solitons,
creating new fires, is balanced by the pair-wise annihilation of oppositely
moving solitons. Two distinct, diverging length scales appear in the limit
where the growth rate of trees, , vanishes. The width of the solitons, ,
diverges as a power law, , while the average distance between solitons
diverges much faster as .Comment: 4 pages with 2 figures include
Two-dimensional cellular automaton model of traffic flow with open boundaries
A two-dimensional cellular automaton model of traffic flow with open
boundaries are investigated by computer simulations. The outflow of cars from
the system and the average velocity are investigated. The time sequences of the
outflow and average velocity have flicker noises in a jamming phase. The low
density behavior are discussed with simple jam-free approximation.Comment: 14 pages, Phys. Rev. E in press, PostScript figures available at
ftp://hirose.ai.is.saga-u.ac.jp/pub/documents/papers/1996/2DTR/
OpenBoundaries/Figs.tar.g
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