77,599 research outputs found
Partitioned Sampling of Public Opinions Based on Their Social Dynamics
Public opinion polling is usually done by random sampling from the entire
population, treating individual opinions as independent. In the real world,
individuals' opinions are often correlated, e.g., among friends in a social
network. In this paper, we explore the idea of partitioned sampling, which
partitions individuals with high opinion similarities into groups and then
samples every group separately to obtain an accurate estimate of the population
opinion. We rigorously formulate the above idea as an optimization problem. We
then show that the simple partitions which contain only one sample in each
group are always better, and reduce finding the optimal simple partition to a
well-studied Min-r-Partition problem. We adapt an approximation algorithm and a
heuristic algorithm to solve the optimization problem. Moreover, to obtain
opinion similarity efficiently, we adapt a well-known opinion evolution model
to characterize social interactions, and provide an exact computation of
opinion similarities based on the model. We use both synthetic and real-world
datasets to demonstrate that the partitioned sampling method results in
significant improvement in sampling quality and it is robust when some opinion
similarities are inaccurate or even missing
Unusual behavior of sound velocity of a Bose gas in an optical superlattice at quasi-one-dimension
A Bose gas trapped in a one-dimensional optical superlattice has emerged as a
novel superfluid characterized by tunable lattice topologies and tailored band
structures. In this work, we focus on the propagation of sound in such a novel
system and have found new features on sound velocity, which arises from the
interplay between the two lattices with different periodicity and is not
present in the case of a condensate in a monochromatic optical lattice.
Particularly, this is the first time that the sound velocity is found to first
increase and then decrease as the superlattice strength increases even at one
dimension. Such unusual behavior can be analytically understood in terms of the
competition between the decreasing compressibility and the increasing effective
mass due to the increasing superlattice strength. This result suggests a new
route to engineer the sound velocity by manipulating the superlattice's
parameters. All the calculations based on the mean-field theory are justified
by checking the exponent of the off-diagonal one-body density matrix
that is much smaller than 1. Finally, the conditions for possible experimental
realization of our scenario are also discussed.Comment: 10 pages, 5 figure
Study on space-time structure of Higgs boson decay using HBT correlation Method in ee collision at =250 GeV
The space-time structure of the Higgs boson decay are carefully studied with
the HBT correlation method using ee collision events produced through
Monte Carlo generator PYTHIA 8.2 at =250GeV. The Higgs boson jets
(Higgs-jets) are identified by H-tag tracing. The measurement of the Higgs
boson radius and decay lifetime are derived from HBT correlation of its decay
final state pions inside Higgs-jets in the ee collisions events with an
upper bound of fm and fs. This result is consistent with CMS data.Comment: 7 pages,3 figure
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