165 research outputs found
Efficient Non-parametric Bayesian Hawkes Processes
In this paper, we develop an efficient nonparametric Bayesian estimation of
the kernel function of Hawkes processes. The non-parametric Bayesian approach
is important because it provides flexible Hawkes kernels and quantifies their
uncertainty. Our method is based on the cluster representation of Hawkes
processes. Utilizing the stationarity of the Hawkes process, we efficiently
sample random branching structures and thus, we split the Hawkes process into
clusters of Poisson processes. We derive two algorithms -- a block Gibbs
sampler and a maximum a posteriori estimator based on expectation maximization
-- and we show that our methods have a linear time complexity, both
theoretically and empirically. On synthetic data, we show our methods to be
able to infer flexible Hawkes triggering kernels. On two large-scale Twitter
diffusion datasets, we show that our methods outperform the current
state-of-the-art in goodness-of-fit and that the time complexity is linear in
the size of the dataset. We also observe that on diffusions related to online
videos, the learned kernels reflect the perceived longevity for different
content types such as music or pets videos
Will This Video Go Viral? Explaining and Predicting the Popularity of Youtube Videos
What makes content go viral? Which videos become popular and why others
don't? Such questions have elicited significant attention from both researchers
and industry, particularly in the context of online media. A range of models
have been recently proposed to explain and predict popularity; however, there
is a short supply of practical tools, accessible for regular users, that
leverage these theoretical results. HIPie -- an interactive visualization
system -- is created to fill this gap, by enabling users to reason about the
virality and the popularity of online videos. It retrieves the metadata and the
past popularity series of Youtube videos, it employs Hawkes Intensity Process,
a state-of-the-art online popularity model for explaining and predicting video
popularity, and it presents videos comparatively in a series of interactive
plots. This system will help both content consumers and content producers in a
range of data-driven inquiries, such as to comparatively analyze videos and
channels, to explain and predict future popularity, to identify viral videos,
and to estimate response to online promotion.Comment: 4 page
- …