Portrait of Sitao Luan is unavailable

Sitao Luan

Postdoctorate - McGill University
Supervisor
Co-supervisor
Research Topics
AI for Science
Data Mining
Graph Neural Networks
Reasoning
Reinforcement Learning

Publications

Is Heterophily A Real Nightmare For Graph Neural Networks To Do Node Classification?
Qincheng Lu
Jiaqi Zhu
Mingde Zhao
Xiao-Wen Chang
A Consciousness-Inspired Planning Agent for Model-Based Reinforcement Learning
We present an end-to-end, model-based deep reinforcement learning agent which dynamically attends to relevant parts of its state during plan… (see more)ning. The agent uses a bottleneck mechanism over a set-based representation to force the number of entities to which the agent attends at each planning step to be small. In experiments, we investigate the bottleneck mechanism with several sets of customized environments featuring different challenges. We consistently observe that the design allows the planning agents to generalize their learned task-solving abilities in compatible unseen environments by attending to the relevant objects, leading to better out-of-distribution generalization performance.
Revisit Policy Optimization in Matrix Form
Xiao-Wen Chang
Break the Ceiling: Stronger Multi-scale Deep Graph Convolutional Networks
Mingde Zhao
Xiao-Wen Chang
Recently, neural network based approaches have achieved significant improvement for solving large, complex, graph-structured problems. Howev… (see more)er, their bottlenecks still need to be addressed, and the advantages of multi-scale information and deep architectures have not been sufficiently exploited. In this paper, we theoretically analyze how existing Graph Convolutional Networks (GCNs) have limited expressive power due to the constraint of the activation functions and their architectures. We generalize spectral graph convolution and deep GCN in block Krylov subspace forms and devise two architectures, both with the potential to be scaled deeper but each making use of the multi-scale information in different ways. We further show that the equivalence of these two architectures can be established under certain conditions. On several node classification tasks, with or without the help of validation, the two new architectures achieve better performance compared to many state-of-the-art methods.
Meta-Learning State-based Eligibility Traces for More Sample-Efficient Policy Evaluation
Mingde Zhao
Xiao-Wen Chang
Temporal-Difference (TD) learning is a standard and very successful reinforcement learning approach, at the core of both algorithms that lea… (see more)rn the value of a given policy, as well as algorithms which learn how to improve policies. TD-learning with eligibility traces provides a way to boost sample efficiency by temporal credit assignment, i.e. deciding which portion of a reward should be assigned to predecessor states that occurred at different previous times, controlled by a parameter