26,951 research outputs found
Top-N Recommender System via Matrix Completion
Top-N recommender systems have been investigated widely both in industry and
academia. However, the recommendation quality is far from satisfactory. In this
paper, we propose a simple yet promising algorithm. We fill the user-item
matrix based on a low-rank assumption and simultaneously keep the original
information. To do that, a nonconvex rank relaxation rather than the nuclear
norm is adopted to provide a better rank approximation and an efficient
optimization strategy is designed. A comprehensive set of experiments on real
datasets demonstrates that our method pushes the accuracy of Top-N
recommendation to a new level.Comment: AAAI 201
The semileptonic baryonic decay
The decay with a proton-antiproton pair in the
final state is unique in the sense that it is the only semileptonic baryonic
decay which is physically allowed in the charmed meson sector. Its measurement
will test our basic knowledge on semileptonic decays and the low-energy
interactions. Taking into account the major intermediate state
contributions from and , we find that its
branching fraction is at the level of . The location and
the nature of state are crucial for the precise determination of the
branching fraction. We wish to trigger a new round of a careful study with the
upcoming more data in BESIII as well as the future super tau-charm factory.Comment: final version, accepted for publication in Phys. Lett.
Branching fractions of semileptonic and decays from the covariant light-front quark model
Based on the predictions of the relevant form factors from the covariant
light-front quark model, we show the branching fractions for the ( or ) decays, where denotes
the pseudoscalar meson, the scalar meson with a mass above 1 GeV, the
vector meson and the axial-vector one. Comparison with the available
experimental results are made, and we find an excellent agreement. The
predictions for other decay modes can be tested in a charm factory, e.g., the
BESIII detector. The future measurements will definitely further enrich our
knowledge on the hadronic transition form factor as well as the inner structure
of the even-parity mesons ( and ).Comment: Predictions on D-> K1(1270), K1(1400) l nu rates correcte
Twin Learning for Similarity and Clustering: A Unified Kernel Approach
Many similarity-based clustering methods work in two separate steps including
similarity matrix computation and subsequent spectral clustering. However,
similarity measurement is challenging because it is usually impacted by many
factors, e.g., the choice of similarity metric, neighborhood size, scale of
data, noise and outliers. Thus the learned similarity matrix is often not
suitable, let alone optimal, for the subsequent clustering. In addition,
nonlinear similarity often exists in many real world data which, however, has
not been effectively considered by most existing methods. To tackle these two
challenges, we propose a model to simultaneously learn cluster indicator matrix
and similarity information in kernel spaces in a principled way. We show
theoretical relationships to kernel k-means, k-means, and spectral clustering
methods. Then, to address the practical issue of how to select the most
suitable kernel for a particular clustering task, we further extend our model
with a multiple kernel learning ability. With this joint model, we can
automatically accomplish three subtasks of finding the best cluster indicator
matrix, the most accurate similarity relations and the optimal combination of
multiple kernels. By leveraging the interactions between these three subtasks
in a joint framework, each subtask can be iteratively boosted by using the
results of the others towards an overall optimal solution. Extensive
experiments are performed to demonstrate the effectiveness of our method.Comment: Published in AAAI 201
Beyond Classification: Latent User Interests Profiling from Visual Contents Analysis
User preference profiling is an important task in modern online social
networks (OSN). With the proliferation of image-centric social platforms, such
as Pinterest, visual contents have become one of the most informative data
streams for understanding user preferences. Traditional approaches usually
treat visual content analysis as a general classification problem where one or
more labels are assigned to each image. Although such an approach simplifies
the process of image analysis, it misses the rich context and visual cues that
play an important role in people's perception of images. In this paper, we
explore the possibilities of learning a user's latent visual preferences
directly from image contents. We propose a distance metric learning method
based on Deep Convolutional Neural Networks (CNN) to directly extract
similarity information from visual contents and use the derived distance metric
to mine individual users' fine-grained visual preferences. Through our
preliminary experiments using data from 5,790 Pinterest users, we show that
even for the images within the same category, each user possesses distinct and
individually-identifiable visual preferences that are consistent over their
lifetime. Our results underscore the untapped potential of finer-grained visual
preference profiling in understanding users' preferences.Comment: 2015 IEEE 15th International Conference on Data Mining Workshop
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