89 research outputs found
Signed Network Modeling Based on Structural Balance Theory
The modeling of networks, specifically generative models, have been shown to
provide a plethora of information about the underlying network structures, as
well as many other benefits behind their construction. Recently there has been
a considerable increase in interest for the better understanding and modeling
of networks, but the vast majority of this work has been for unsigned networks.
However, many networks can have positive and negative links(or signed
networks), especially in online social media, and they inherently have
properties not found in unsigned networks due to the added complexity.
Specifically, the positive to negative link ratio and the distribution of
signed triangles in the networks are properties that are unique to signed
networks and would need to be explicitly modeled. This is because their
underlying dynamics are not random, but controlled by social theories, such as
Structural Balance Theory, which loosely states that users in social networks
will prefer triadic relations that involve less tension. Therefore, we propose
a model based on Structural Balance Theory and the unsigned Transitive Chung-Lu
model for the modeling of signed networks. Our model introduces two parameters
that are able to help maintain the positive link ratio and proportion of
balanced triangles. Empirical experiments on three real-world signed networks
demonstrate the importance of designing models specific to signed networks
based on social theories to obtain better performance in maintaining signed
network properties while generating synthetic networks.Comment: CIKM 2018: https://dl.acm.org/citation.cfm?id=327174
Relational Multi-Task Learning: Modeling Relations between Data and Tasks
A key assumption in multi-task learning is that at the inference time the
multi-task model only has access to a given data point but not to the data
point's labels from other tasks. This presents an opportunity to extend
multi-task learning to utilize data point's labels from other auxiliary tasks,
and this way improves performance on the new task. Here we introduce a novel
relational multi-task learning setting where we leverage data point labels from
auxiliary tasks to make more accurate predictions on the new task. We develop
MetaLink, where our key innovation is to build a knowledge graph that connects
data points and tasks and thus allows us to leverage labels from auxiliary
tasks. The knowledge graph consists of two types of nodes: (1) data nodes,
where node features are data embeddings computed by the neural network, and (2)
task nodes, with the last layer's weights for each task as node features. The
edges in this knowledge graph capture data-task relationships, and the edge
label captures the label of a data point on a particular task. Under MetaLink,
we reformulate the new task as a link label prediction problem between a data
node and a task node. The MetaLink framework provides flexibility to model
knowledge transfer from auxiliary task labels to the task of interest. We
evaluate MetaLink on 6 benchmark datasets in both biochemical and vision
domains. Experiments demonstrate that MetaLink can successfully utilize the
relations among different tasks, outperforming the state-of-the-art methods
under the proposed relational multi-task learning setting, with up to 27%
improvement in ROC AUC.Comment: ICLR 2022 Spotligh
AutoTransfer: AutoML with Knowledge Transfer -- An Application to Graph Neural Networks
AutoML has demonstrated remarkable success in finding an effective neural
architecture for a given machine learning task defined by a specific dataset
and an evaluation metric. However, most present AutoML techniques consider each
task independently from scratch, which requires exploring many architectures,
leading to high computational cost. Here we propose AutoTransfer, an AutoML
solution that improves search efficiency by transferring the prior
architectural design knowledge to the novel task of interest. Our key
innovation includes a task-model bank that captures the model performance over
a diverse set of GNN architectures and tasks, and a computationally efficient
task embedding that can accurately measure the similarity among different
tasks. Based on the task-model bank and the task embeddings, we estimate the
design priors of desirable models of the novel task, by aggregating a
similarity-weighted sum of the top-K design distributions on tasks that are
similar to the task of interest. The computed design priors can be used with
any AutoML search algorithm. We evaluate AutoTransfer on six datasets in the
graph machine learning domain. Experiments demonstrate that (i) our proposed
task embedding can be computed efficiently, and that tasks with similar
embeddings have similar best-performing architectures; (ii) AutoTransfer
significantly improves search efficiency with the transferred design priors,
reducing the number of explored architectures by an order of magnitude.
Finally, we release GNN-Bank-101, a large-scale dataset of detailed GNN
training information of 120,000 task-model combinations to facilitate and
inspire future research.Comment: ICLR 202
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