17,095 research outputs found
Discrete-time Temporal Network Embedding via Implicit Hierarchical Learning in Hyperbolic Space
Representation learning over temporal networks has drawn considerable
attention in recent years. Efforts are mainly focused on modeling structural
dependencies and temporal evolving regularities in Euclidean space which,
however, underestimates the inherent complex and hierarchical properties in
many real-world temporal networks, leading to sub-optimal embeddings. To
explore these properties of a complex temporal network, we propose a hyperbolic
temporal graph network (HTGN) that fully takes advantage of the exponential
capacity and hierarchical awareness of hyperbolic geometry. More specially,
HTGN maps the temporal graph into hyperbolic space, and incorporates hyperbolic
graph neural network and hyperbolic gated recurrent neural network, to capture
the evolving behaviors and implicitly preserve hierarchical information
simultaneously. Furthermore, in the hyperbolic space, we propose two important
modules that enable HTGN to successfully model temporal networks: (1)
hyperbolic temporal contextual self-attention (HTA) module to attend to
historical states and (2) hyperbolic temporal consistency (HTC) module to
ensure stability and generalization. Experimental results on multiple
real-world datasets demonstrate the superiority of HTGN for temporal graph
embedding, as it consistently outperforms competing methods by significant
margins in various temporal link prediction tasks. Specifically, HTGN achieves
AUC improvement up to 9.98% for link prediction and 11.4% for new link
prediction. Moreover, the ablation study further validates the representational
ability of hyperbolic geometry and the effectiveness of the proposed HTA and
HTC modules.Comment: KDD202
Dynamic Hyperbolic Attention Network for Fine Hand-object Reconstruction
Reconstructing both objects and hands in 3D from a single RGB image is
complex. Existing methods rely on manually defined hand-object constraints in
Euclidean space, leading to suboptimal feature learning. Compared with
Euclidean space, hyperbolic space better preserves the geometric properties of
meshes thanks to its exponentially-growing space distance, which amplifies the
differences between the features based on similarity. In this work, we propose
the first precise hand-object reconstruction method in hyperbolic space, namely
Dynamic Hyperbolic Attention Network (DHANet), which leverages intrinsic
properties of hyperbolic space to learn representative features. Our method
that projects mesh and image features into a unified hyperbolic space includes
two modules, ie. dynamic hyperbolic graph convolution and image-attention
hyperbolic graph convolution. With these two modules, our method learns mesh
features with rich geometry-image multi-modal information and models better
hand-object interaction. Our method provides a promising alternative for fine
hand-object reconstruction in hyperbolic space. Extensive experiments on three
public datasets demonstrate that our method outperforms most state-of-the-art
methods.Comment: Accpeted by ICCV 202
Matching Biomedical Ontologies via a Hybrid Graph Attention Network
Biomedical ontologies have been used extensively to formally define and organize biomedical terminologies, and these ontologies are typically manually created by biomedical experts. With more biomedical ontologies being built independently, matching them to address the problem of heterogeneity and interoperability has become a critical challenge in many biomedical applications. Existing matching methods have mostly focused on capturing features of terminological, structural, and contextual semantics in ontologies. However, these feature engineering-based techniques are not only labor-intensive but also ignore the hidden semantic relations in ontologies. In this study, we propose an alternative biomedical ontology-matching framework BioHAN via a hybrid graph attention network, and that consists of three techniques. First, we propose an effective ontology-enriching method that refines and enriches the ontologies through axioms and external resources. Subsequently, we use hyperbolic graph attention layers to encode hierarchical concepts in a unified hyperbolic space. Finally, we aggregate the features of both the direct and distant neighbors with a graph attention network. Experimental results on real-world biomedical ontologies demonstrate that BioHAN is competitive with the state-of-the-art ontology matching methods
CoSyn: Detecting Implicit Hate Speech in Online Conversations Using a Context Synergized Hyperbolic Network
The tremendous growth of social media users interacting in online
conversations has also led to significant growth in hate speech. Most of the
prior works focus on detecting explicit hate speech, which is overt and
leverages hateful phrases, with very little work focusing on detecting hate
speech that is implicit or denotes hatred through indirect or coded language.
In this paper, we present CoSyn, a user- and conversational-context synergized
network for detecting implicit hate speech in online conversation trees. CoSyn
first models the user's personal historical and social context using a novel
hyperbolic Fourier attention mechanism and hyperbolic graph convolution
network. Next, we jointly model the user's personal context and the
conversational context using a novel context interaction mechanism in the
hyperbolic space that clearly captures the interplay between the two and makes
independent assessments on the amounts of information to be retrieved from both
contexts. CoSyn performs all operations in the hyperbolic space to account for
the scale-free dynamics of social media. We demonstrate the effectiveness of
CoSyn both qualitatively and quantitatively on an open-source hate speech
dataset with Twitter conversations and show that CoSyn outperforms all our
baselines in detecting implicit hate speech with absolute improvements in the
range of 8.15% - 19.50%.Comment: Under review at IJCAI 202
\{kappa}HGCN: Tree-likeness Modeling via Continuous and Discrete Curvature Learning
The prevalence of tree-like structures, encompassing hierarchical structures
and power law distributions, exists extensively in real-world applications,
including recommendation systems, ecosystems, financial networks, social
networks, etc. Recently, the exploitation of hyperbolic space for tree-likeness
modeling has garnered considerable attention owing to its exponential growth
volume. Compared to the flat Euclidean space, the curved hyperbolic space
provides a more amenable and embeddable room, especially for datasets
exhibiting implicit tree-like architectures. However, the intricate nature of
real-world tree-like data presents a considerable challenge, as it frequently
displays a heterogeneous composition of tree-like, flat, and circular regions.
The direct embedding of such heterogeneous structures into a homogeneous
embedding space (i.e., hyperbolic space) inevitably leads to heavy distortions.
To mitigate the aforementioned shortage, this study endeavors to explore the
curvature between discrete structure and continuous learning space, aiming at
encoding the message conveyed by the network topology in the learning process,
thereby improving tree-likeness modeling. To the end, a curvature-aware
hyperbolic graph convolutional neural network, \{kappa}HGCN, is proposed, which
utilizes the curvature to guide message passing and improve long-range
propagation. Extensive experiments on node classification and link prediction
tasks verify the superiority of the proposal as it consistently outperforms
various competitive models by a large margin.Comment: KDD 202
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