3,324 research outputs found
A Survey on Graph Kernels
Graph kernels have become an established and widely-used technique for
solving classification tasks on graphs. This survey gives a comprehensive
overview of techniques for kernel-based graph classification developed in the
past 15 years. We describe and categorize graph kernels based on properties
inherent to their design, such as the nature of their extracted graph features,
their method of computation and their applicability to problems in practice. In
an extensive experimental evaluation, we study the classification accuracy of a
large suite of graph kernels on established benchmarks as well as new datasets.
We compare the performance of popular kernels with several baseline methods and
study the effect of applying a Gaussian RBF kernel to the metric induced by a
graph kernel. In doing so, we find that simple baselines become competitive
after this transformation on some datasets. Moreover, we study the extent to
which existing graph kernels agree in their predictions (and prediction errors)
and obtain a data-driven categorization of kernels as result. Finally, based on
our experimental results, we derive a practitioner's guide to kernel-based
graph classification
Modeling Complex Networks For (Electronic) Commerce
NYU, Stern School of Business, IOMS Department, Center for Digital Economy Researc
Semi-supervised Domain Adaptation on Graphs with Contrastive Learning and Minimax Entropy
Label scarcity in a graph is frequently encountered in real-world
applications due to the high cost of data labeling. To this end,
semi-supervised domain adaptation (SSDA) on graphs aims to leverage the
knowledge of a labeled source graph to aid in node classification on a target
graph with limited labels. SSDA tasks need to overcome the domain gap between
the source and target graphs. However, to date, this challenging research
problem has yet to be formally considered by the existing approaches designed
for cross-graph node classification. To tackle the SSDA problem on graphs, a
novel method called SemiGCL is proposed, which benefits from graph contrastive
learning and minimax entropy training. SemiGCL generates informative node
representations by contrasting the representations learned from a graph's local
and global views. Additionally, SemiGCL is adversarially optimized with the
entropy loss of unlabeled target nodes to reduce domain divergence.
Experimental results on benchmark datasets demonstrate that SemiGCL outperforms
the state-of-the-art baselines on the SSDA tasks
Deep Learning with Partially Labeled Data for Radio Map Reconstruction
In this paper, we address the problem of Received Signal Strength map
reconstruction based on location-dependent radio measurements and utilizing
side knowledge about the local region; for example, city plan, terrain height,
gateway position. Depending on the quantity of such prior side information, we
employ Neural Architecture Search to find an optimized Neural Network model
with the best architecture for each of the supposed settings. We demonstrate
that using additional side information enhances the final accuracy of the
Received Signal Strength map reconstruction on three datasets that correspond
to three major cities, particularly in sub-areas near the gateways where larger
variations of the average received signal power are typically observed.Comment: 42 pages, 39 figure
Deep Learning Methods for Vessel Trajectory Prediction based on Recurrent Neural Networks
Data-driven methods open up unprecedented possibilities for maritime
surveillance using Automatic Identification System (AIS) data. In this work, we
explore deep learning strategies using historical AIS observations to address
the problem of predicting future vessel trajectories with a prediction horizon
of several hours. We propose novel sequence-to-sequence vessel trajectory
prediction models based on encoder-decoder recurrent neural networks (RNNs)
that are trained on historical trajectory data to predict future trajectory
samples given previous observations. The proposed architecture combines Long
Short-Term Memory (LSTM) RNNs for sequence modeling to encode the observed data
and generate future predictions with different intermediate aggregation layers
to capture space-time dependencies in sequential data. Experimental results on
vessel trajectories from an AIS dataset made freely available by the Danish
Maritime Authority show the effectiveness of deep-learning methods for
trajectory prediction based on sequence-to-sequence neural networks, which
achieve better performance than baseline approaches based on linear regression
or on the Multi-Layer Perceptron (MLP) architecture. The comparative evaluation
of results shows: i) the superiority of attention pooling over static pooling
for the specific application, and ii) the remarkable performance improvement
that can be obtained with labeled trajectories, i.e., when predictions are
conditioned on a low-level context representation encoded from the sequence of
past observations, as well as on additional inputs (e.g., port of departure or
arrival) about the vessel's high-level intention, which may be available from
AIS.Comment: Accepted for publications in IEEE Transactions on Aerospace and
Electronic Systems, 17 pages, 9 figure
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