Presenters: George Karypis, Zheng Zhang, Minjie Wang, Da Zheng, Quan Gan

Time: (UTC/GMT +8) 09:00-16:30, April, 20, Monday

Learning from graph and relational data plays a major role in many applications including social network analysis, marketing, e-commerce, information retrieval, knowledge modeling, medical and biological sciences, engineering, and others. In the last few years, Graph Neural Networks (GNNs) have emerged as a promising new supervised learning framework capable of bringing the power of deep representation learning to graph and relational data. This ever-growing body of research has shown that GNNs achieve state-of-the-art performance for problems such as link prediction, fraud detection, target-ligand binding activity prediction, knowledge-graph completion, and product recommendations.

The objective of this tutorial is twofold. First, it will provide an overview of the theory behind GNNs, discuss the types of problems that GNNs are well suited for, and introduce some of the most widely used GNN model architectures and problems/applications that are designed to solve. Second, it will introduce the Deep Graph Library (DGL), a new software framework that simplifies the development of efficient GNN-based training and inference programs. To make things concrete, the tutorial will provide hands-on sessions using DGL. This hands-on part will cover both basic graph applications (e.g., node classification and link prediction), as well as more advanced topics including training GNNs on large graphs and in a distributed setting. In addition, it will provide hands-on tutorials on using GNNs and DGL for real-world applications such as recommendation and fraud detection.

The attendees should have some experience with deep learning and have used deep learning frameworks such as MXNet, Pytorch, and TensorFlow. Attendees should have experience with the various problems and techniques arising and used in graph learning and analysis, but it is not required.

• Section 1: Overview of Graph Neural Networks. This section describes how graph neural networks operate, their underlying theory, and their advantages over alternative graph learning approaches. In addition, it describes various learning problems on graphs and shows how GNNs can be used to solve them.
• Section 2: Overview of Deep Graph Library (DGL). This section describes the different abstractions and APIs that DGL provides, which are designed to simplify the implementation of GNN models, and explains how DGL interfaces with MXNet, Pytorch, and TensorFlow. It then proceeds to introduce DGL’s message-passing API that can be used to develop arbitrarily complex GNNs and the pre-defined GNN nn modules that it provides.
• Section 3: GNN models for basic graph tasks. This section demonstrates how to use GNNs to solve four key graph learning tasks: node classification, link prediction, graph classification, and network embedding pre-training. It will show how GraphSage, a popular GNN model, can be implemented with DGL’s nn module and show how the node embeddings computed by GraphSage can be used in different types of downstream tasks. In addition, it will demonstrate the implementation of a customized GNN model with DGL’s message passing interface.
• Section 4: GNN training on large graphs. This section uses some of the models described in Section 3 to demonstrate mini-batch training, multi-GPU training, and distributed training in DGL. It starts by describing how the concept of mini-batch training applies to GNNs and how mini-batch computations can be sped up by using various sampling techniques. It then proceeds to illustrate how one such sampling technique, called neighbor sampling, can be implemented in DGL using a Jupyter notebook. This notebook is then extended to show multi-GPU training and distributed training.
• Section 5: GNN models for real-world applications. This section uses the techniques described in the earlier sections to show how GNNs can be used to develop scalable solutions for recommendation and fraud detection. For recommendation, it develops a nearest-neighbor item-based recommendation method that employs a GNN model to learn item embeddings by following an end-to-end learning approach. For fraud detection, it extends the node classification model in the previous section to work on heterogeneous graphs and addresses the scenario where there exist few labelled samples.

Join our Slack channel "WWW20-tutorial" for discussion.