11,751 research outputs found
Unsupervised Story Discovery from Continuous News Streams via Scalable Thematic Embedding
Unsupervised discovery of stories with correlated news articles in real-time
helps people digest massive news streams without expensive human annotations. A
common approach of the existing studies for unsupervised online story discovery
is to represent news articles with symbolic- or graph-based embedding and
incrementally cluster them into stories. Recent large language models are
expected to improve the embedding further, but a straightforward adoption of
the models by indiscriminately encoding all information in articles is
ineffective to deal with text-rich and evolving news streams. In this work, we
propose a novel thematic embedding with an off-the-shelf pretrained sentence
encoder to dynamically represent articles and stories by considering their
shared temporal themes. To realize the idea for unsupervised online story
discovery, a scalable framework USTORY is introduced with two main techniques,
theme- and time-aware dynamic embedding and novelty-aware adaptive clustering,
fueled by lightweight story summaries. A thorough evaluation with real news
data sets demonstrates that USTORY achieves higher story discovery performances
than baselines while being robust and scalable to various streaming settings.Comment: Accepted by SIGIR'2
Extracting News Events from Microblogs
Twitter stream has become a large source of information for many people, but
the magnitude of tweets and the noisy nature of its content have made
harvesting the knowledge from Twitter a challenging task for researchers for a
long time. Aiming at overcoming some of the main challenges of extracting the
hidden information from tweet streams, this work proposes a new approach for
real-time detection of news events from the Twitter stream. We divide our
approach into three steps. The first step is to use a neural network or deep
learning to detect news-relevant tweets from the stream. The second step is to
apply a novel streaming data clustering algorithm to the detected news tweets
to form news events. The third and final step is to rank the detected events
based on the size of the event clusters and growth speed of the tweet
frequencies. We evaluate the proposed system on a large, publicly available
corpus of annotated news events from Twitter. As part of the evaluation, we
compare our approach with a related state-of-the-art solution. Overall, our
experiments and user-based evaluation show that our approach on detecting
current (real) news events delivers a state-of-the-art performance
Dynamic feature selection for clustering high dimensional data streams
open access articleChange in a data stream can occur at the concept level and at the feature level. Change at the feature level can occur if new, additional features appear in the stream or if the importance and relevance of a feature changes as the stream progresses. This type of change has not received as much attention as concept-level change. Furthermore, a lot of the methods proposed for clustering streams (density-based, graph-based, and grid-based) rely on some form of distance as a similarity metric and this is problematic in high-dimensional data where the curse of dimensionality renders distance measurements and any concept of “density” difficult. To address these two challenges we propose combining them and framing the problem as a feature selection problem, specifically a dynamic feature selection problem. We propose a dynamic feature mask for clustering high dimensional data streams. Redundant features are masked and clustering is performed along unmasked, relevant features. If a feature's perceived importance changes, the mask is updated accordingly; previously unimportant features are unmasked and features which lose relevance become masked. The proposed method is algorithm-independent and can be used with any of the existing density-based clustering algorithms which typically do not have a mechanism for dealing with feature drift and struggle with high-dimensional data. We evaluate the proposed method on four density-based clustering algorithms across four high-dimensional streams; two text streams and two image streams. In each case, the proposed dynamic feature mask improves clustering performance and reduces the processing time required by the underlying algorithm. Furthermore, change at the feature level can be observed and tracked
Temporal word embeddings for dynamic user profiling in Twitter
The research described in this paper focused on exploring
the domain of user profiling, a nascent and contentious technology which
has been steadily attracting increased interest from the research community as its potential for providing personalised digital services is realised.
An extensive review of related literature revealed that limited research
has been conducted into how temporal aspects of users can be captured
using user profiling techniques. This, coupled with the notable lack of
research into the use of word embedding techniques to capture temporal
variances in language, revealed an opportunity to extend the Random Indexing word embedding technique such that the interests of users could
be modelled based on their use of language. To achieve this, this work
concerned itself with extending an existing implementation of Temporal
Random Indexing to model Twitter users across multiple granularities of
time based on their use of language. The product of this is a novel technique for temporal user profiling, where a set of vectors is used to describe
the evolution of a Twitter user’s interests over time through their use of
language. The vectors produced were evaluated against a temporal implementation of another state-of-the-art word embedding technique, the
Word2Vec Dynamic Independent Skip-gram model, where it was found
that Temporal Random Indexing outperformed Word2Vec in the generation of temporal user profiles
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