2,434 research outputs found
Ultra accurate collaborative information filtering via directed user similarity
A key challenge of the collaborative filtering (CF) information filtering is
how to obtain the reliable and accurate results with the help of peers'
recommendation. Since the similarities from small-degree users to large-degree
users would be larger than the ones opposite direction, the large-degree users'
selections are recommended extensively by the traditional second-order CF
algorithms. By considering the users' similarity direction and the second-order
correlations to depress the influence of mainstream preferences, we present the
directed second-order CF (HDCF) algorithm specifically to address the challenge
of accuracy and diversity of the CF algorithm. The numerical results for two
benchmark data sets, MovieLens and Netflix, show that the accuracy of the new
algorithm outperforms the state-of-the-art CF algorithms. Comparing with the CF
algorithm based on random-walks proposed in the Ref.7, the average ranking
score could reach 0.0767 and 0.0402, which is enhanced by 27.3\% and 19.1\% for
MovieLens and Netflix respectively. In addition, the diversity, precision and
recall are also enhanced greatly. Without relying on any context-specific
information, tuning the similarity direction of CF algorithms could obtain
accurate and diverse recommendations. This work suggests that the user
similarity direction is an important factor to improve the personalized
recommendation performance.Comment: 6 pages, 4 figure
A Cooperative Perception System Robust to Localization Errors
Cooperative perception is challenging for safety-critical autonomous driving
applications.The errors in the shared position and pose cause an inaccurate
relative transform estimation and disrupt the robust mapping of the Ego
vehicle. We propose a distributed object-level cooperative perception system
called OptiMatch, in which the detected 3D bounding boxes and local state
information are shared between the connected vehicles. To correct the noisy
relative transform, the local measurements of both connected vehicles (bounding
boxes) are utilized, and an optimal transport theory-based algorithm is
developed to filter out those objects jointly detected by the vehicles along
with their correspondence, constructing an associated co-visible set. A
correction transform is estimated from the matched object pairs and further
applied to the noisy relative transform, followed by global fusion and dynamic
mapping. Experiment results show that robust performance is achieved for
different levels of location and heading errors, and the proposed framework
outperforms the state-of-the-art benchmark fusion schemes, including early,
late, and intermediate fusion, on average precision by a large margin when
location and/or heading errors occur.Comment: Accepted by IEEE IV 202
Fluctuation-Driven Vortex Fractionalization in Topologically Ordered Superfluids of Cold Atoms
We have studied spin structures of fluctuation-driven fractionalized vortices
and topological spin order in 2D nematic superfluids of cold sodium atoms. Our
Monte Carlo simulations suggest a softened pi-spin disclination structure in a
half-quantum vortex when spin correlations are short ranged; in addition,
calculations indicate that a unique non-local topological spin order emerges
simultaneously as cold atoms become a superfluid below a critical temperature.
We have also estimated fluctuation-dependent critical frequencies for
half-quantum vortex nucleation in rotating optical traps and discussed probing
these excitations in experiments.Comment: 5 pages, 2 figures; revised version accepted by Europhysics Letter
Integrable Open Spin Chains from Flavored ABJM Theory
We compute the two-loop anomalous dimension matrix in the scalar sector of
planar flavored ABJM theory. Using coordinate Bethe ansatz, we
obtain the reflection matrix and confirm that the boundary Yang-Baxter
equations are satisfied. This establishes the integrability of this theory in
the scalar sector at the two-loop order.Comment: v2, 25 pages, 2 figures, minor corrections, references adde
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