94 research outputs found
The Brownian Web: Characterization and Convergence
The Brownian Web (BW) is the random network formally consisting of the paths
of coalescing one-dimensional Brownian motions starting from every space-time
point in . We extend the earlier work of Arratia
and of T\'oth and Werner by providing characterization and convergence results
for the BW distribution, including convergence of the system of all coalescing
random walkssktop/brownian web/finale/arXiv submits/bweb.tex to the BW under
diffusive space-time scaling. We also provide characterization and convergence
results for the Double Brownian Web, which combines the BW with its dual
process of coalescing Brownian motions moving backwards in time, with forward
and backward paths ``reflecting'' off each other. For the BW, deterministic
space-time points are almost surely of ``type'' -- {\em zero} paths
into the point from the past and exactly {\em one} path out of the point to the
future; we determine the Hausdorff dimension for all types that actually occur:
dimension 2 for type , 3/2 for and , 1 for , and 0
for and .Comment: 52 pages with 4 figure
Cell capacity of LMDS systems in typical traffic scenarios
Broadband access and multimedia technologies are expected to be primary drivers for the telecommunications market of the next few years. The increasing bandwidth needs, together with the plethora of different services and heterogeneous traffic flows, requires accurate methodologies for resource dimensioning, especially in the field of wireless technologies where efficient bandwidth usage is crucial. New methodologies need to be based on up-to-date traffic source modeling and usage scenarios. Therefore, in this article we propose a survey of statistical characterization of single traffic sources, QoS requirements and different traffic demands. When possible, we consider the aggregate traffic resulting from a large number of heavy tailed ON/OFF sources, relying on the theory of long-range dependent flows. This method is particularly useful when time- and resource-consuming simulations are needed in order to dimension the system resources, which is always the case in the multimedia scenarios of future networks. We use such a traffic framework to estimate by simulations the capacity of an LMDS system
Electrochemical Characterization and CO2 Reduction Reaction of a Family of Pyridazine-Bridged Dinuclear Mn(I) Carbonyl Complexes
Three recently synthesized neutral dinuclear carbonyl manganese complexes with the pyridazine bridging ligand, of general formula [Mn2(μ-ER)2(CO)6(μ-pydz)] (pydz = pyridazine; E = O or S; R = methyl or phenyl), have been investigated by cyclic voltammetry in dimethylformamide and acetonitrile both under an inert argon atmosphere and in the presence of carbon dioxide. This family of Mn(I) compounds behaves interestingly at negative potentials in the presence of CO2. Based on this behavior, which is herein discussed, a rather efficient catalytic mechanism for the CO2 reduction reaction toward the generation of CO has been hypothesized
1D Aging
We derive exact expressions for a number of aging functions that are scaling
limits of non-equilibrium correlations, R(tw,tw+t) as tw --> infinity with t/tw
--> theta, in the 1D homogenous q-state Potts model for all q with T=0 dynamics
following a quench from infinite temperature. One such quantity is (the
two-point, two-time correlation function) when
n/sqrt(tw) --> z. Exact, closed-form expressions are also obtained when one or
more interludes of infinite temperature dynamics occur. Our derivations express
the scaling limit via coalescing Brownian paths and a ``Brownian space-time
spanning tree,'' which also yields other aging functions, such as the
persistence probability of no spin flip at 0 between tw and tw+t.Comment: 4 pages (RevTeX); 2 figures; submitted to Physical Review Letter
Does consultation improve decision-making?
This paper reports an experiment designed to test whether prior consultation within a group affects subsequent individual decision-making in tasks where demonstrability of correct solutions is low. In our experiment, subjects considered two paintings created by two different artists and were asked to guess which artist made each painting. We observed answers given by individuals under two treatments: In one, subjects were allowed the opportunity to consult with other participants before making their private decisions; in the other, there was no such opportunity. Our primary findings are that subjects in the first treatment evaluate the opportunity to consult positively, but they perform significantly worse and earn significantly less
Observing galaxy clusters and the cosmic web through the Sunyaev Zel'dovich effect with MISTRAL
Galaxy clusters and surrounding medium, can be studied using X-ray
bremsstrahlung emission and Sunyaev Zel'dovich (SZ) effect. Both astrophysical
probes, sample the same environment with different parameters dependance. The
SZ effect is relatively more sensitive in low density environments and thus is
useful to study the filamentary structures of the cosmic web. In addition,
observations of the matter distribution require high angular resolution in
order to be able to map the matter distribution within and around galaxy
clusters. MISTRAL is a camera working at 90GHz which, once coupled to the
Sardinia Radio Telescope, can reach angular resolution over field
of view (f.o.v.). The forecasted sensitivity is
and the mapping speed is . MISTRAL was recently
installed at the focus of the SRT and soon will take its first photons.Comment: To appear in Proc. of the mm Universe 2023 conference, Grenoble
(France), June 2023, published by F. Mayet et al. (Eds), EPJ Web of
conferences, EDP Science
MISTRAL and its KIDs
The MIllimetric Sardinia radio Telescope Receiver based on Array of Lumped elements KIDs, MISTRAL, is a cryogenic W-band (77–103 GH) LEKID camera which will be integrated at the Gregorian focus of the 64 m aperture Sardinia Radio Telescope, in Italy, in Autumn 2022. This instrument, thanks to its high angular resolution (∼13arcsec) and the wide instantaneous field of view (∼4arcmin), will allow continuum surveys of the mm-wave sky with a variety of scientific targets, spanning from extragalactic astrophysics to solar system science. In this contribution, we will describe the design of the MISTRAL camera, with a particular focus on the optimisation and test of a prototype of the focal plane
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