Graph Machine Learning

7 min read

What is Graph Machine Learning?

Graph machine learning is a subfield of machine learning that focuses on using graph-structured data to perform predictive and analytical tasks. In graphs, data is represented as nodes (vertices) and edges (links), capturing complex relationships and interactions between entities. Unlike traditional data, which is often tabular, graph data is inherently interconnected, making it suitable for modeling social networks, biological networks, communication networks, and more. Graph machine learning leverages algorithms designed to exploit these connections, such as Graph Neural Networks (GNNs), to learn from the structure and attributes of graphs. These algorithms can perform tasks like node classification, link prediction, and graph clustering. By learning from the topology and features of graphs, these models can uncover hidden patterns, predict future connections, and identify influential nodes within the network. The ability to handle and analyze graph data opens up new possibilities for solving complex problems in various domains, from recommending friends on social media to predicting molecular properties in drug discovery.

How does graph machine learning work?

Graph machine learning works by leveraging the unique structure and relationships inherent in graph data to perform various predictive and analytical tasks. Here’s a breakdown of the process:

  • Graph Representation: Data is represented as a graph, consisting of nodes (representing entities) and edges (representing relationships). Each node and edge can have associated features, providing additional context.

  • Feature Extraction: Features from nodes, edges, and the overall graph structure are extracted. This can include node attributes (e.g., user profiles in social networks) and structural features (e.g., node degree, centrality measures).

  • Graph Neural Networks (GNNs): GNNs are the primary models used in graph machine learning. They extend traditional neural networks to operate on graph data by aggregating information from a node’s neighbors. This process, called message passing or neighborhood aggregation, allows the model to learn representations that capture both local and global graph structures.

  • Propagation and Aggregation: During training, each node’s feature vector is updated by combining its own features with aggregated features from its neighbors. This iterative process enables nodes to gather information from multi-hop neighborhoods, enriching their representations.

  • Learning and Optimization: The GNN is trained using standard machine learning techniques, such as backpropagation and gradient descent. The objective is to minimize a loss function tailored to the specific task, like node classification, link prediction, or graph classification.

  • Prediction and Inference: Once trained, the model can be used to make predictions. For example, in node classification, the model predicts the label of each node based on its learned representation. In link prediction, the model estimates the likelihood of new or missing edges. Graph machine learning models excel in capturing the complex dependencies and patterns within graph-structured data, making them powerful tools for applications ranging from social network analysis to drug discovery.

Graphs in machine learning applications

Graph-powered machine learning effectively combines the strengths of machine learning and graph data structures to enhance data analysis and predictive capabilities. Graphs, which represent entities and their relationships, are a natural fit for machine learning due to their ability to capture complex dependencies and interactions. This synergy is especially powerful in the era of big data, where the volume, variety, and velocity of data necessitate advanced tools for effective analysis. Graphs provide an ideal framework for integrating diverse data sources into a cohesive structure, allowing for richer data models and more accurate insights. In the machine learning project lifecycle, graphs facilitate data management, from transforming raw data into interconnected nodes and edges to applying sophisticated algorithms like centrality measures, PageRank, and community detection. These techniques uncover valuable patterns, such as influential nodes and community structures, which are crucial for applications like recommendation systems and network analysis. Additionally, graph databases enhance the storage and retrieval of machine learning models, ensuring fast access and efficient performance. Visualizing graph data further aids in understanding and interpreting complex relationships, making graphs an invaluable tool for modern machine learning projects. For a deeper dive into graph machine learning applications, explore how these techniques are revolutionizing various industries

Graph Powered Machine Learning Webinar, Slides and Q&A Session

As you know, we hosted an open Q&A event with our very own Dr. Alessandro Negro - the Chief Scientist at GraphAware and author of the book Graph-Powered Machine Learning. We’d like to share some of the highlights from the event for those of you who missed it.

The event opened with an introduction from GraphAware CEO, Michal Bachman, who shared his excitement over the perfect timing of the book. To quote, Michal said, more and more people are starting to realize that graphs and machine learning are “a natural fit, a match made in heaven.”

Alessandro also highlighted the perfect timing of the book being published, bringing value for people who are currently using graphs and starting to realize they want to do something more. “As if we could see the future.”

Graph-Powered Machine Learning should definitely be on the to-read list of every data scientist as it talks about new possibilities and opportunities to solve problems in the field. However, the book is also a good read for industry newbies. For instance, the first three chapters provide a broader understanding of the field, and the simple introductory sections in each part of the book introduce the reader to the main problems of recommendation, fraud detection, and natural language processing. The book can also serve as a bible of graph-powered machine learning, referring, and pointing you to many other articles and books that can provide more insight and information on certain topics. For a deeper information, please check our graph machine learning slides.

Here are some more event highlights:

Top issues machine learning can help with

One thing that machine learning can do better than humans is processing vast amounts of data faster. Humans, on the other hand, are better at making accurate decisions. Thus, machines and machine learning can be beneficial in dealing with issues that require large amounts of data to be processed fast. The key to solving projects that we could not solve effectively before is the collaboration of machines and humans. This brings us to one of the core beliefs we hold at GraphAware, and share with Alessandro - AI should be understood as augmented rather than artificial intelligence. In other words, machines and humans have the potential to accomplish more complex tasks when working together. We want to help make this happen faster by drawing attention to the human at the center of this collaboration. We believe human abstracting capabilities will be the power of AI in the future.

Scalability = the key challenge to fast adoption of graph-powered machine learning

The key obstacle to the fast adoption of graph-powered machine learning is the dimension of the data many organizations nowadays have. The large amounts of data we have, and keep collecting, translates to the issues of processing it, managing the source of knowledge, finding the right hardware, software, and algorithms to use to process this amount of data. Scalability is thus the next big challenge that will need to be dealt with in the future.

The story behind the cover

The author is a proud Italian from Apulia, who wanted to honor his roots and origin. That is why the cover features a Tarantella dancer. Tarantella is a traditional folk dance of the Apulia region that is still a living tradition today. You can read more about this in the first pages of the book. (Special thanks to Manning, for allowing him to do this as they usually choose the covers of the books they publish themselves.)

Alessandro’s favorite machine learning project

When Alessandro started with machine learning, he wrote the first library on top of Neo4j that provided recommendations. This library, and the approaches used in it, are still applicable now. Yet, recommendations are one of the most needed (across various contexts and industries), and the most challenging machine learning projects. That is why - partly due to the sentiment and the challenging nature and complexity of recommendations - they are still Alessandro’s personal favorite.

The second book

And finally, we need to talk about the second book. This book will be a continuation of Graph-Powered Machine Learning, and will focus on Knowledge Graphs and knowledge graph algorithms. Our whole research team is writing the book, so you’re really in for a treat. The MEAP version should be available by Manning by the beginning of next year, meaning you will most likely be able to read the first chapters in January or February.

Liberating Knowledge Machine Learning techniques with Dr Alessandro Negro, Christophe Willemsen

In this video, GraphAware introduces Hume, a sophisticated platform designed to enhance how we access and utilize knowledge. It addresses the fundamental challenge of efficiently sharing human knowledge due to communication barriers. Hume’s comprehensive data processing pipeline includes data ingestion, structuring, and enrichment through advanced techniques like entity recognition and external knowledge bases. The platform utilizes a Knowledge Graph framework to transform raw data into actionable insights, facilitating informed decision-making across different domains. This approach aims to overcome the limitations of traditional communication methods by enabling more efficient interaction with information and fostering deeper understanding through advanced data analysis and machine learning applications.