1,332 research outputs found
Free-Form Composition Networks for Egocentric Action Recognition
Egocentric action recognition is gaining significant attention in the field
of human action recognition. In this paper, we address data scarcity issue in
egocentric action recognition from a compositional generalization perspective.
To tackle this problem, we propose a free-form composition network (FFCN) that
can simultaneously learn disentangled verb, preposition, and noun
representations, and then use them to compose new samples in the feature space
for rare classes of action videos. First, we use a graph to capture the
spatial-temporal relations among different hand/object instances in each action
video. We thus decompose each action into a set of verb and preposition
spatial-temporal representations using the edge features in the graph. The
temporal decomposition extracts verb and preposition representations from
different video frames, while the spatial decomposition adaptively learns verb
and preposition representations from action-related instances in each frame.
With these spatial-temporal representations of verbs and prepositions, we can
compose new samples for those rare classes in a free-form manner, which is not
restricted to a rigid form of a verb and a noun. The proposed FFCN can directly
generate new training data samples for rare classes, hence significantly
improve action recognition performance. We evaluated our method on three
popular egocentric action recognition datasets, Something-Something V2, H2O,
and EPIC-KITCHENS-100, and the experimental results demonstrate the
effectiveness of the proposed method for handling data scarcity problems,
including long-tailed and few-shot egocentric action recognition
On predictability of rare events leveraging social media: a machine learning perspective
Information extracted from social media streams has been leveraged to
forecast the outcome of a large number of real-world events, from political
elections to stock market fluctuations. An increasing amount of studies
demonstrates how the analysis of social media conversations provides cheap
access to the wisdom of the crowd. However, extents and contexts in which such
forecasting power can be effectively leveraged are still unverified at least in
a systematic way. It is also unclear how social-media-based predictions compare
to those based on alternative information sources. To address these issues,
here we develop a machine learning framework that leverages social media
streams to automatically identify and predict the outcomes of soccer matches.
We focus in particular on matches in which at least one of the possible
outcomes is deemed as highly unlikely by professional bookmakers. We argue that
sport events offer a systematic approach for testing the predictive power of
social media, and allow to compare such power against the rigorous baselines
set by external sources. Despite such strict baselines, our framework yields
above 8% marginal profit when used to inform simple betting strategies. The
system is based on real-time sentiment analysis and exploits data collected
immediately before the games, allowing for informed bets. We discuss the
rationale behind our approach, describe the learning framework, its prediction
performance and the return it provides as compared to a set of betting
strategies. To test our framework we use both historical Twitter data from the
2014 FIFA World Cup games, and real-time Twitter data collected by monitoring
the conversations about all soccer matches of four major European tournaments
(FA Premier League, Serie A, La Liga, and Bundesliga), and the 2014 UEFA
Champions League, during the period between Oct. 25th 2014 and Nov. 26th 2014.Comment: 10 pages, 10 tables, 8 figure
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