7,031 research outputs found
Modelling of Sound Events with Hidden Imbalances Based on Clustering and Separate Sub-Dictionary Learning
This paper proposes an effective modelling of sound event spectra with a
hidden data-size-imbalance, for improved Acoustic Event Detection (AED). The
proposed method models each event as an aggregated representation of a few
latent factors, while conventional approaches try to find acoustic elements
directly from the event spectra. In the method, all the latent factors across
all events are assigned comparable importance and complexity to overcome the
hidden imbalance of data-sizes in event spectra. To extract latent factors in
each event, the proposed method employs clustering and performs non-negative
matrix factorization to each latent factor, and learns its acoustic elements as
a sub-dictionary. Separate sub-dictionary learning effectively models the
acoustic elements with limited data-sizes and avoids over-fitting due to hidden
imbalances in training data. For the task of polyphonic sound event detection
from DCASE 2013 challenge, an AED based on the proposed modelling achieves a
detection F-measure of 46.5%, a significant improvement of more than 19% as
compared to the existing state-of-the-art methods
Dynamic Poisson Factorization
Models for recommender systems use latent factors to explain the preferences
and behaviors of users with respect to a set of items (e.g., movies, books,
academic papers). Typically, the latent factors are assumed to be static and,
given these factors, the observed preferences and behaviors of users are
assumed to be generated without order. These assumptions limit the explorative
and predictive capabilities of such models, since users' interests and item
popularity may evolve over time. To address this, we propose dPF, a dynamic
matrix factorization model based on the recent Poisson factorization model for
recommendations. dPF models the time evolving latent factors with a Kalman
filter and the actions with Poisson distributions. We derive a scalable
variational inference algorithm to infer the latent factors. Finally, we
demonstrate dPF on 10 years of user click data from arXiv.org, one of the
largest repository of scientific papers and a formidable source of information
about the behavior of scientists. Empirically we show performance improvement
over both static and, more recently proposed, dynamic recommendation models. We
also provide a thorough exploration of the inferred posteriors over the latent
variables.Comment: RecSys 201
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