This IMPRESS-U project is jointly funded by NSF, Estonian Research Council (ETAG), Research Council of Lithuania (LMT), National Science Center of Poland (NCN), US National Academy of Sciences, and Office of Naval Research Global (DoD). The research will be performed in a multilateral international partnership that unites the University of Florida (US), G.E. Pukhov Institute for Modelling in Energy Engineering of the NAS of Ukraine (PIMEE), Kiyv (Ukraine), National Technical University of Ukraine ?Igor Sikorsky Kyiv Polytechnic Institute? (Ukraine), Institute of Theoretical & Applied Informatics, Gliwice (Poland), Mykolas Romeris University, Vilnius (Lithuania), and Tallinn University of Technology, Tallinn (Estonia). US portion of the collaborative effort will be co-funded by NSF OISE/OD and CISE/CNS. <br/><br/>NON-TECHNICAL SUMMARY <br/>This funding is awarded through an EAGER proposal, supporting the vital development of the Resilience-Recovery Under Attack (RRUA) framework. Originating in response to global disruptions like the COVID-19 pandemic, supply chain vulnerabilities, and geopolitical conflicts, the project holds significant importance. Focusing on Ukraine's digital services sector, which has faced persistent external shocks due to the ongoing conflict, this initiative is both timely and crucial. The primary objective is to establish connections between Ukrainian scientists and their counterparts in the West, mitigating the isolation caused by geopolitical tensions and fostering a collaborative research network dedicated to systemic resilience. Involving an international partnership comprising the USA, Ukraine, Poland, Estonia, and Lithuania, the project adopts an interdisciplinary approach, leveraging network science, resilience analytics, explainable AI, and digital twin technologies. Beyond enhancing Ukraine's infrastructural resilience, the project aspires to serve as a blueprint for global resilience strategies in analogous contexts.<br/>To achieve broader impact, the Dallas-Fort Worth airport will function as the initial RRUA testbed for co-development and training. The RRUA concept and methods will undergo testing in Poland, Estonia, and Lithuania's energy and communications infrastructure, culminating in their application to Ukraine's digital infrastructure. In addition to advancing research goals, this project is steadfast in its commitment to promoting inclusivity in science and engineering. It actively involves junior Ukrainian researchers, facilitating their integration into the global scientific community. Educational opportunities will be offered through digital platforms, workshops, and simulation games, aligning with EU-Ukraine events. These initiatives aim to provide a distinctive learning experience, nurturing a new generation of scientists equipped with the skills to address complex resilience challenges and aligning with the NSF's mission to advance national health, prosperity, and welfare.<br/><br/>TECHNICAL SUMMARY<br/>This NSF EAGER project award aims to advance resilience science by developing the Resilience-Recovery Under Attack (RRUA) framework, with a focus on the unique challenges faced by Ukraine's digital services sector. The RRUA framework introduces an innovative and comprehensive approach to resilience science, targeting the complex interdependencies of interconnected infrastructural systems subjected to dynamic threats and shocks. Hence, the project represents a significant leap from traditional resilience strategies that emphasize prevention, instead integrating recovery as a core component of the resilience paradigm. <br/> We aim to validate the hypothesis that the recovery and resilience of systems under threats and system response stages to diverse shocks can be quantified via stress-testing of interconnected networks representing their systemic functions. We aim to provide novel insights into the lifecycle of resilience under external shocks during acute and persistent shocks, and in particular quantify the key controllers of each of the resilience-response phases to inform efficient recovery interventions. By employing a multi-faceted methodology combining network science, resilience analytics, explainable AI (xAI), and digital twin technologies, the project seeks to redefine systemic recovery modeling and adaptation of interconnected infrastructure across Ukraine, benefiting from the shared knowledge of our proposed international partnership with the USA, Ukraine, Poland, Estonia, and Lithuania. The project utilizes a three-pronged approach: refining RRUA using data-rich analyses at a US-based international airport, testing concepts and methods in Poland, Estonia and Lithuania testbeds, including human behavior components of vulnerability, and subsequently integrating RRUA within Ukraine's cyber and energy infrastructure systems in the presence of dynamic threats and variable data. Success could revolutionize Ukraine's prospects for recovery, positioning it as a global example for resilience strategies. Our research design will collaboratively explore how to operationalize our RRUA framework across varied settings.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.