8,041 research outputs found
The topological structure of scaling limits of large planar maps
We discuss scaling limits of large bipartite planar maps. If p is a fixed
integer strictly greater than 1, we consider a random planar map M(n) which is
uniformly distributed over the set of all 2p-angulations with n faces. Then, at
least along a suitable subsequence, the metric space M(n) equipped with the
graph distance rescaled by the factor n to the power -1/4 converges in
distribution as n tends to infinity towards a limiting random compact metric
space, in the sense of the Gromov-Hausdorff distance. We prove that the
topology of the limiting space is uniquely determined independently of p, and
that this space can be obtained as the quotient of the Continuum Random Tree
for an equivalence relation which is defined from Brownian labels attached to
the vertices. We also verify that the Hausdorff dimension of the limit is
almost surely equal to 4.Comment: 45 pages Second version with minor modification
Study of winglets applied to biplanes
The possibility of improving the aerodynamic characteristics of a biplane configuration by adding winglets is examined both theoretically and experimentally. Theoretical calculations show good agreement with experiment in predicting inviscid drag due to lift. Theoretical and experimental results indicate that the addition of winglets to an optimized biplane configuration can increase the ideal efficiency factor by up to 13 percent, as well as increasing the lift curve slope and maximum lift coefficient
Bessel processes, the Brownian snake and super-Brownian motion
We prove that, both for the Brownian snake and for super-Brownian motion in
dimension one, the historical path corresponding to the minimal spatial
position is a Bessel process of dimension -5. We also discuss a spine
decomposition for the Brownian snake conditioned on the minimizing path.Comment: Submitted to the special volume of S\'eminaire de Probabilit\'es in
  memory of Marc Yo
Feller property and infinitesimal generator of the exploration process
We consider the exploration process associated to the continuous random tree
(CRT) built using a Levy process with no negative jumps. This process has been
studied by Duquesne, Le Gall and Le Jan. This measure-valued Markov process is
a useful tool to study CRT as well as super-Brownian motion with general
branching mechanism. In this paper we prove this process is Feller, and we
compute its infinitesimal generator on exponential functionals and give the
corresponding martingale
Automated microorganism Sample Collection Module
Modified Gelman Sampler obtains representative sample of microorganism population. Proposed Sample Collection Module is based on direct inoculation of selected solid growth media encased in a cartridge at all times except during inoculation. Cartridge can be handled with no danger of contamination to sample or operator
A Decidable Confluence Test for Cognitive Models in ACT-R
Computational cognitive modeling investigates human cognition by building
detailed computational models for cognitive processes. Adaptive Control of
Thought - Rational (ACT-R) is a rule-based cognitive architecture that offers a
widely employed framework to build such models. There is a sound and complete
embedding of ACT-R in Constraint Handling Rules (CHR). Therefore analysis
techniques from CHR can be used to reason about computational properties of
ACT-R models. For example, confluence is the property that a program yields the
same result for the same input regardless of the rules that are applied.
  In ACT-R models, there are often cognitive processes that should always yield
the same result while others e.g. implement strategies to solve a problem that
could yield different results. In this paper, a decidable confluence criterion
for ACT-R is presented. It allows to identify ACT-R rules that are not
confluent. Thereby, the modeler can check if his model has the desired
behavior.
  The sound and complete translation of ACT-R to CHR from prior work is used to
come up with a suitable invariant-based confluence criterion from the CHR
literature. Proper invariants for translated ACT-R models are identified and
proven to be decidable. The presented method coincides with confluence of the
original ACT-R models.Comment: To appear in Stefania Costantini, Enrico Franconi, William Van
  Woensel, Roman Kontchakov, Fariba Sadri, and Dumitru Roman: "Proceedings of
  RuleML+RR 2017". Springer LNC
Magnetization reversal and spin dynamics exchange in biased F/AF bilayers probed with complex permeability spectra
The spin dynamics of the ferromagnetic pinned layer of
ferro-antiferromagnetic coupled NiFe/MnNi bilayers is investigated in a broad
frequency range (30 MHz-6 GHz). A phenomenological model based on the
Landau-Lifshitz equation for the complex permeability of the F/AF bilayer is
proposed. The experimental results are compared to theoretical predictions. We
show that the resonance frequencies, measured during the magnetization, are
likewise hysteretic.Comment: 4 pages, 4 figure
A spectroscopic look at the gravitationally lensed type Ia SN 2016geu at z=0.409
The spectacular success of type Ia supernovae (SNe Ia) in SN-cosmology is
based on the assumption that their photometric and spectroscopic properties are
invariant with redshift. However, this fundamental assumption needs to be
tested with observations of high-z SNe Ia. To date, the majority of SNe Ia
observed at moderate to large redshifts (0.4 < z < 1.0) are faint, and the
resultant analyses are based on observations with modest signal-to-noise ratios
that impart a degree of ambiguity in their determined properties. In rare cases
however, the Universe offers a helping hand: to date a few SNe Ia have been
observed that have had their luminosities magnified by intervening galaxies and
galaxy clusters acting as gravitational lenses. In this paper we present
long-slit spectroscopy of the lensed SNe Ia 2016geu, which occurred at a
redshift of z=0.409, and was magnified by a factor of ~55 by a galaxy located
at z=0.216. We compared our spectra, which were obtained a couple weeks to a
couple months past peak light, with the spectroscopic properties of
well-observed, nearby SNe Ia, finding that SN 2016geu's properties are
commensurate with those of SNe Ia in the local universe. Based primarily on the
velocity and strength of the Si II 6355 absorption feature, we find that SN
2016geu can be classified as a high-velocity, high-velocity gradient and
"core-normal" SN Ia. The strength of various features (measured though their
pseudo-equivalent widths) argue against SN 2016geu being a faint, broad-lined,
cool or shallow-silicon SN Ia. We conclude that the spectroscopic properties of
SN 2016geu imply that it is a normal SN Ia, and when taking previous results by
other authors into consideration, there is very little, if any, evolution in
the observational properties of SNe Ia up to z~0.4. [Abridged]Comment: 12 pages, 5 figures, 4 tables. Submitted to MNRAS. Comments welcome
Spin dynamics in exchange-biased F/AF bilayers
The spin dynamics of the ferromagnetic pinned layer of
ferro-antiferromagnetic coupled NiFe/MnNi bilayers is investigated in a broad
frequency range (30 MHz-6 GHz). A phenomenological model based on the
Landau-Lifshitz equation for the complex permeability of the F/AF bilayer is
proposed. The experimental results are compared to theoretical predictions.Comment: 12 pages, 3 figures, 1 tabl
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