16,119 research outputs found
STS-CCL: Spatial-Temporal Synchronous Contextual Contrastive Learning for Urban Traffic Forecasting
Efficiently capturing the complex spatiotemporal representations from
large-scale unlabeled traffic data remains to be a challenging task. In
considering of the dilemma, this work employs the advanced contrastive learning
and proposes a novel Spatial-Temporal Synchronous Contextual Contrastive
Learning (STS-CCL) model. First, we elaborate the basic and strong augmentation
methods for spatiotemporal graph data, which not only perturb the data in terms
of graph structure and temporal characteristics, but also employ a
learning-based dynamic graph view generator for adaptive augmentation. Second,
we introduce a Spatial-Temporal Synchronous Contrastive Module (STS-CM) to
simultaneously capture the decent spatial-temporal dependencies and realize
graph-level contrasting. To further discriminate node individuals in negative
filtering, a Semantic Contextual Contrastive method is designed based on
semantic features and spatial heterogeneity, achieving node-level contrastive
learning along with negative filtering. Finally, we present a hard mutual-view
contrastive training scheme and extend the classic contrastive loss to an
integrated objective function, yielding better performance. Extensive
experiments and evaluations demonstrate that building a predictor upon STS-CCL
contrastive learning model gains superior performance than existing traffic
forecasting benchmarks. The proposed STS-CCL is highly suitable for large
datasets with only a few labeled data and other spatiotemporal tasks with data
scarcity issue.Comment: This work was accepted by the 49th IEEE International Conference on
Acoustics, Speech, & Signal Processing (ICASSP 2024). We will present our
work in Seoul, Kore
Detectability thresholds and optimal algorithms for community structure in dynamic networks
We study the fundamental limits on learning latent community structure in
dynamic networks. Specifically, we study dynamic stochastic block models where
nodes change their community membership over time, but where edges are
generated independently at each time step. In this setting (which is a special
case of several existing models), we are able to derive the detectability
threshold exactly, as a function of the rate of change and the strength of the
communities. Below this threshold, we claim that no algorithm can identify the
communities better than chance. We then give two algorithms that are optimal in
the sense that they succeed all the way down to this limit. The first uses
belief propagation (BP), which gives asymptotically optimal accuracy, and the
second is a fast spectral clustering algorithm, based on linearizing the BP
equations. We verify our analytic and algorithmic results via numerical
simulation, and close with a brief discussion of extensions and open questions.Comment: 9 pages, 3 figure
Sparsity in Dynamics of Spontaneous Subtle Emotions: Analysis \& Application
Spontaneous subtle emotions are expressed through micro-expressions, which
are tiny, sudden and short-lived dynamics of facial muscles; thus poses a great
challenge for visual recognition. The abrupt but significant dynamics for the
recognition task are temporally sparse while the rest, irrelevant dynamics, are
temporally redundant. In this work, we analyze and enforce sparsity constrains
to learn significant temporal and spectral structures while eliminate
irrelevant facial dynamics of micro-expressions, which would ease the challenge
in the visual recognition of spontaneous subtle emotions. The hypothesis is
confirmed through experimental results of automatic spontaneous subtle emotion
recognition with several sparsity levels on CASME II and SMIC, the only two
publicly available spontaneous subtle emotion databases. The overall
performances of the automatic subtle emotion recognition are boosted when only
significant dynamics are preserved from the original sequences.Comment: IEEE Transaction of Affective Computing (2016
Dance-the-music : an educational platform for the modeling, recognition and audiovisual monitoring of dance steps using spatiotemporal motion templates
In this article, a computational platform is presented, entitled “Dance-the-Music”, that can be used in a dance educational context to explore and learn the basics of dance steps. By introducing a method based on spatiotemporal motion templates, the platform facilitates to train basic step models from sequentially repeated dance figures performed by a dance teacher. Movements are captured with an optical motion capture system. The teachers’ models can be visualized from a first-person perspective to instruct students how to perform the specific dance steps in the correct manner. Moreover, recognition algorithms-based on a template matching method can determine the quality of a student’s performance in real time by means of multimodal monitoring techniques. The results of an evaluation study suggest that the Dance-the-Music is effective in helping dance students to master the basics of dance figures
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