Dimitrios Letsios


Welcome to my personal webpage! My name is Dimitrios Letsios and I am a lecturer (assistant professor) in the Department of Informatics at King's College London and a member of the Algorithms and Data Analysis Group. The foundations of my research are in algorithms and computational optimization, especially at their intersection with data science and artificial intelligence. You can find my CV here.


Professional Appointments & Studies

  • Lecturer in Algorithms and Data Analysis. King's College London (UK). September 2019 - Present.
  • Postdoctoral Research Associate in Computational Optimisation. Imperial College London (UK). July 2016 - August 2019.
  • Teaching and Research Assistant in Combinatorics, Optimization, and Algorithms for Telecommunications. INRIA Sophia Antipolis - Méditerranée and Université Nice - Sophia Antipolis (France). September 2015 - July 2016.
  • Postdoctoral Researcher in Algorithms and Complexity. Technische Universität München (Germany). June 2014 - July 2015.
  • Teaching and Research Assistant in Operational Research. Université Pierre et Marie Curie (France). September 2013 - May 2014.
  • Visiting Researcher in Algorithms. University of Pittsburgh (USA). November 2010 - December 2010.
  • Ph.D. in Computer Science, Université d'Evry Val d'Essonne (France), February 2010 - October 2013.
  • M.Sc. in Computer Science, Athens University of Economics and Business (Greece), October 2008 - January 2010.
  • B.Sc. in Informatics, Athens University of Economics and Business (Greece), September 2004 - September 2008.

Research Interests & Selected Publications

Data-Driven Robust Scheduling and Vehicle Routing for Transportation Problems

  • D. Letsios, J. T. Bradley, S. G, R. Misener, N. Page. Approximate and Robust Bounded Job Start Scheduling for Royal Mail Delivery Offices. Journal of Scheduling 24(2), p. 237-258, 2021.  
  • D. Letsios, M. Mistry, R. Misener. Exact Lexicographic Scheduling and Approximate Rescheduling. European Journal of Operational Research 290(2), p.469-478, 2021.  

Mixed-Integer Optimization for Process Systems Engineering

  • M. Mistry, D. Letsios, G. Krennrich, R. M. Lee, R. Misener. Mixed-Integer Convex Nonlinear Optimization with Gradient-Boosted Trees Embedded. INFORMS Journal on Computing 33(3), p. 1103-1119, 2021.  
  • D. Letsios, R. Baltean-Lugojan, F. Ceccon, M. Mistry, J. Wiebe, R. Misener. Approximation Algorithms for Process Systems Engineering. Computers and Chemical Engineering 132, 106599, 2020.    
  • D. Letsios, G. Kouyialis, R. Misener. Heuristics with Performance Guarantees for the Minimum Number of Matches Problem in Heat Recovery Network Design. Computers and Chemical Engineering 113, p.57-85, 2018.    

Computational Argumentation for Explainable Optimization in Healthcare.

  • K. Cyras, M. Lee, D. Letsios. Schedule Explainer: An Argumentation-Supported Tool for Interactive Explanations in Makespan Scheduling. International Workshop on Explainable and Transparent AI and Multi-Agent Systems (EXTRAAMAS), p. 243-259, 2021.
  • K. Cyras, A. Karamlou, M. Lee, D. Letsios, R. Misener, F. Toni. AI-assisted Schedule Explainer for Nurse Rostering. International Conference on Autonomous Agents and Multi-agent Systems (AAMAS), p. 2101-2103, 2020. Best innovative demonstration award.  
  • K. Cyras, D. Letsios, R. Misener, F. Toni. Argumentation for Explainable Scheduling. AAAI Conference on Artificial Intelligence (AAAI), p. 2752-2759, 2019.

Approximation and Online Algorithms for Energy Efficient Computing

  • E. Angel, E.Bampis, F. Kacem, D. Letsios. Speed Scaling on Parallel Processors with Migration. Journal of Combinatorial Optimization 37(4), p. 1266-1282, 2019.  
  • E. Bampis, A. Kononov, D. Letsios, G. Lucarelli, M. Sviridenko. Energy-Efficient Scheduling and Routing via Randomized Rounding. Journal of Scheduling 21(1), p.35-51, 2018.  
  • S. Albers, E. Bampis, D. Letsios, G. Lucarelli, R. Stotz. Scheduling on Power-Heterogeneous Processors. Information and Computation 257, p. 22-33, 2017.  
  • E. Angel, E. Bampis, V. Chau, D. Letsios. Throughput Maximization for Speed-Scaling with Agreeable Deadlines. Journal of Scheduling 19(6), p. 619-625, 2016.  
  • E. Bampis, D. Letsios, I. Milis, G. Zois. Speed Scaling for Maximum Lateness. Theory of Computing Systems 58(2), p. 304-321, 2016.  
  • E. Bampis, A. Kononov, D. Letsios, G. Lucarelli, I. Nemparis. From Preemptive to Non-preemptive Speed-Scaling Scheduling. Discrete Applied Mathematics 181, p. 11-20, 2015.  
  • E. Bampis, D. Letsios, G. Lucarelli. Green Scheduling, Flows and Matchings. Theoretical Computer Science 579, p. 126-136, 2015.  

Community Service

Program Committees

  • International Conference on Theory and Applications of Models of Computation (TAMC 2022)
  • International Joint Conference on Artificial Intelligence - European Conference on Artificial Intelligence, Survey Track (IJCAI-ECAI 2022)
  • AAAI Explainable Agency in Artificial Intelligence Workshop (EAAI-AAAI 2022)
  • AAAI Explainable Agency in Artificial Intelligence Workshop (XAI-AAAI 2021)
  • AAAI Conference on Artificial Intelligence (AAAI 2021)
  • International Joint Conference on Artificial Intelligence - Pacific Rim International Conference on Artificial Intelligence (IJCAI - PRICAI 2020)
  • International Workshop on Combinatorial Algorithms (IWOCA 2020)
  • IJCAI Workshop on Explainable Artificial Intelligence (XAI 2019)
  • International Parallel and Distributed Processing Symposium (IPDPS 2019)
  • International Conference on Parallel Processing (ICPP 2017)

Organizing Committees

  • London Stringology Days and London Algorithmic Workshop (LSD&LAW 2020) [Co-Chair]  
  • ICALP Satellite Workshop on Approximation, Parameterized and Exact Algorithms (APEX 2013)

Journal External Reviewing

  • Algorithmica, Computational Optimization and Applications (COAP), Future Generation Computer Systems, INFORMS Journal on Computing (IJOC), Journal of Global Optimization (JOGO), Journal of Parallel and Distributed Computing (JPDC), Journal of Scheduling (JOSH), International Journal of Production Research, Omega - The International Journal of Management Science, Operational Research - An International Journal (ORIJ), Parallel Processing Letters (PPL), RAIRO Operations Research, Theoretical Computer Science (TCS), IEEE Transactions on Parallel and Distributed Systems (TPDS)

Conference External Reviewing

  • SPAA 2021, IPCO 2021, IPDPS 2020, IPCO 2019, SPAA 2018, ACC 2017, CIAC 2017, COCOA 2017, Euro-Par 2017, CIAC 2016, COCOA 2016, DOOR 2016, ICALP 2016, ISCO 2016, SODA 2016, ESA 2015, Euro-Par 2015, SEA 2015, SODA 2015, SOFSEM 2015, WADS 2015, CCGrid 2014, IPDPS 2014, ISCO 2014, WAOA 2014, CIAC 2013, ICALP 2013, IPDPS 2013, Euro-Par 2012, ISCO 2012, IPDPS 2012, SEA 2012, WAOA 2012, WAOA 2011, WAOA 2010


Teaching

Primary Instructor

  • Data Mining. M.Sc. Data Science, M.Sc. Artificial Intelligence, M.Sc. Urban Informatics, King's College London. Spring 2020 - present.

Teaching Assistant

  • Computational Optimization. M.Sc. Computing, Imperial College London, Fall 2018.
  • Machine Learning. M.Sc. Business Analytics, Imperial College London, Fall 2018.
  • Probabilities and Statistics. BSc Management Science, Université de Nice, Spring 2016.
  • Object-Oriented Programming (Java). BSc Informatics, Université de Nice, Fall 2015.
  • Data Structures (Python). BSc Informatics, Université de Nice, Fall 2015.
  • Introduction to Programming (Python). BSc Informatics, Université de Nice, Fall 2015.
  • Introduction Foundations of Computer Science. BSc Informatics, Université de Nice, Fall 2015.
  • Online and Approximation Algorithms. M.Sc. Informatics, Technische Universität München, Spring 2015.
  • Randomized Algorithms. M.Sc. Informatics, Technische Universität München, Fall 2014.
  • Special Topics on Algorithms. MSc Informatics, Université Pierre et Marie Curie, Spring 2014.
  • Introduction to Programming (C). MSc Informatics, Université Pierre et Marie Curie, Spring 2014.
  • Data Structures (C). MSc Informatics, Université Pierre et Marie Curie, Fall 2013.
  • Mathematical Programming. MSc Informatics, Université d'Evry, Spring 2011 - Spring 2013.
  • Algorithms. BSc Informatics, Université d'Evry, Spring 2011 - Spring 2013.
  • Introduction to Programming (Java). BSc Informatics, Université d'Evry, Fall 2012.
  • Introduction to Programming (C). BSc Chemistry, Université d'Evry, Fall 2010 - Fall 2011.

Students

Prospective Students

  • Candidates interested in pursuing a PhD under my advice are invited to contact me with their CV and a brief statement of interest (no more than 1-2 paragraphs). Because the application process for PhD positions at King's requires a research proposal (3-4 pages), you may want to request advice about this with your first contact.
  • Successful PhD applicants are expected to: (i) have obtained or be close to obtaining an M.Sc. degree in computer science, mathematics, engineering, or other relevant discipline, (ii) demonstrate their interest and skills on algorithms, data science, and artificial intelligence (analytical thinking with mathematical rigor will be needed), (iii) have reasonable programming skills (Python coding will be needed), and (iv) have good communication skills in English.

PhD Students

  • Anna Collins (March 2020 - present)

Dissertation Topics

  • Data Analysis and Optimization for Bike Sharing.
  • Data Analysis and Optimization for Vehicle Routing Problems.
  • Vehicle Positioning and Forecasting for Ambulance Services.
  • Robustness Analysis for Resource Allocation Problems.
  • Optimization Models and Algorithms for Energy Efficient Computing.
  • Piecewise and Segmented Regression Analysis.


Contact Details

  dimitrios.letsios@kcl.ac.uk
  Office N5.12, Bush House, 30 Aldwych, London, WC2B 4BG