Critical infrastructure refers to the physical and cyber systems and assets that are essential for the functioning of a society and economy. This includes sectors such as energy, transportation, water, communication, and healthcare. The protection of critical infrastructure is crucial to national security, as disruptions or damages to these systems can have devastating societal and economic impacts. Research in critical infrastructure focuses on identifying vulnerabilities, developing strategies for resilience and protection, and improving the overall security and reliability of these essential systems. This research area often involves collaborations between government agencies, industry partners, and academic institutions to address complex challenges and ensure the continued operation of critical infrastructure in the face of evolving threats and risks.