83 research outputs found
Random Delays and the Synchronization of Chaotic Maps
We investigate the dynamics of an array of logistic maps coupled with random
delay times. We report that for adequate coupling strength the array is able to
synchronize, in spite of the random delays. Specifically, we find that the
synchronized state is a homogeneous steady-state, where the chaotic dynamics of
the individual maps is suppressed. This differs drastically from the
synchronization with instantaneous and fixed-delay coupling, as in those cases
the dynamics is chaotic. Also in contrast with the instantaneous and
fixed-delay cases, the synchronization does not dependent on the connection
topology, depends only on the average number of links per node. We find a
scaling law that relates the distance to synchronization with the randomness of
the delays. We also carry out a statistical linear stability analysis that
confirms the numerical results and provides a better understanding of the
nontrivial roles of random delayed interactions.Comment: 5 pages, 5 figure
Inferring long memory processes in the climate network via ordinal pattern analysis
We use ordinal patterns and symbolic analysis to construct global climate
networks and uncover long and short term memory processes. The data analyzed is
the monthly averaged surface air temperature (SAT field) and the results
suggest that the time variability of the SAT field is determined by patterns of
oscillatory behavior that repeat from time to time, with a periodicity related
to intraseasonal oscillations and to El Ni\~{n}o on seasonal-to-interannual
time scales.Comment: 10 pages, 13 figures Enlarged version, new sections and figures.
Accepted in Chao
Student Conceptual Difficulties in Hydrodynamics
We describe a study on the conceptual difficulties faced by college students
in understanding hydrodynamics of ideal fluids. This study was based on
responses obtained in hundreds of written exams and oral interviews, which were
held with first-year Engineering and Science university students. Their
responses allowed us to identify a series of misconceptions unreported in the
literature so far. The study findings demonstrate that the most important
difficulties arise from the students' inability to establish a link between the
kinematics and dynamics of moving fluids, and from a lack of understanding
regarding how different regions of a system interact.Comment: 12 pages, 10 figures (small corrections
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