Researchers at the Department of Energy’s Pacific Northwest National Laboratory (PNNL) have demonstrated how web search engine algorithms can be applied to enhance the protection of critical infrastructure, such as power grids, water treatment plants, food processing facilities, and hospitals.
A study recently published in Homeland Security Affairs details how search engine ranking principles can help prioritize infrastructure protection efforts. The research is based on Google’s PageRank algorithm, which ranks web pages based on their connectivity and influence within a network. The PNNL team adapted this approach to analyze infrastructure networks, identifying facilities that play a crucial role in maintaining overall system stability.
“This research provides a framework for identifying which infrastructure assets should be prioritized in the face of potential threats such as cyberattacks,” said Bill Kay, a mathematician and lead researcher on the project. “Understanding which facilities have the greatest influence within a network allows planners to take proactive measures to mitigate risks.”
Preventing Cascading Failures
A key focus of the research was to determine which facilities are most vulnerable and which have the potential to cause widespread disruptions if compromised. The study highlights the importance of identifying infrastructure that both influences and is influenced by other critical assets — similar to how interconnected websites impact search rankings.
Kay illustrated the concept by explaining how the failure of a single power substation could disrupt operations at a water treatment plant, which in turn could affect nearby hospitals or industrial facilities. While existing backup systems help mitigate these risks, the ability to predict and address potential cascading failures remains essential for infrastructure resilience.
Multilayer Approach to Risk Assessment
The research team enhanced the traditional PageRank algorithm by incorporating a multilayer analysis, allowing them to examine multiple infrastructure systems simultaneously. This approach accounts for interdependencies among sectors such as electricity, transportation, and healthcare, providing a more comprehensive understanding of potential vulnerabilities.
“A multilayer approach is akin to analyzing a complex system from multiple perspectives at once, rather than in isolation,” said Patrick Mackey, coauthor of the study. “This method offers a clearer picture of how different infrastructure components interact and helps pinpoint the most critical elements.”
Simulations conducted by the team demonstrated that their multilayer model could mitigate failures more effectively than conventional approaches. While the study does not quantify the extent of improvement compared to existing methods, it presents a strong case for further exploration of network science in infrastructure protection.
“This type of analysis provides a foundational tool that can be augmented with expert domain knowledge,” said Kay. “It serves as an initial step in strengthening infrastructure resilience.”
Supporting National Security Efforts
The research is part of a broader initiative led by PNNL researcher Sam Chatterjee, principal investigator and chief data scientist. Funded by the Cybersecurity and Infrastructure Security Agency (CISA), the project aims to develop consistent and defensible analytical methods for evaluating infrastructure risks.
“This work exemplifies how network science can be leveraged to address critical infrastructure challenges,” said Chatterjee.
In addition to Kay and Mackey, former intern Jacob Miller contributed to the project.
