The University of Cologne, one of Europe's largest and oldest universities, is seeking a Doctoral Researcher/PhD Student (f/m/x) for the Department of Information Systems for Sustainable Society (IS3) under the supervision of Prof. Dr. Wolfgang Ketter. The IS3 chair conducts interdisciplinary research using methods from machine learning, data analytics, economics, and behavioral science to advance the sustainability of mobility and energy systems. The successful candidate will engage in research on smart energy and mobility systems, employing quantitative methods such as machine learning, reinforcement learning, optimization, and simulation. Responsibilities include publishing research in leading journals in computer science, information systems, and management, participating in faculty research activities, and contributing to teaching, particularly in advanced machine learning. Applicants should hold an excellent Master's degree in information systems, computer science, management, economics, or a related field, with strong quantitative and programming skills (especially Python). Additional programming experience (e.g., Julia, R, Rust, C) is advantageous. Excellent English proficiency is required, and German skills are beneficial. The position offers a diverse and inclusive work environment, support for work-life balance, flexible working models, professional development opportunities, and the possibility of remote work. The contract is part-time (29.87 hours/week), starting 1 February 2026 and ending 31 January 2029, with salary according to Entgeltgruppe 13 TV-L. Applications from women and underrepresented groups are encouraged. Apply online with all required documents (no photo) by 15 December 2025. For further information, contact Prof. Dr. Wolfgang Ketter or Julius Kuhmann.