Optimisation research group

Description

Solving an optimisation problem is about finding solutions that satisfy constraints. One is often interested in the best solutions. Our group focuses on discrete optimisation, where a solution might be an allocation of resources (say a personnel roster, with work regulations and employee preferences as constraints), a packing (say of containers), a plan, a set of routes (say of vehicles in logistics, or of dataflows in a communication network), a schedule (say a school timetable), or a plan for energy usage (say for the charging of electric buses).

The challenge is to find good solutions fast. Our research focuses on identifying new and efficient optimisation models and methods, often driven by real-world applications, and usually drawing from the subfields of mathematical programming, constraint programming, and local search.

Research Topics

• Constraint programming (CP) is an AI approach to optimisation: modelling languages; high-level constraints; high-level types for decision variables; symmetry breaking
• Local search (LS): modelling languages; search languages; solver design; autonomous search
• Mathematical optimisation (MP): efficient mathematical modelling; linear programming (LP); mixed integer (linear) programming (MIP)
• Applied optimisation: air traffic management; resource allocation in networks and mobile communications; cutting patterns for sawmills; software testing, analysis, and verification; vehicle routing for waste management; vehicle routing for winter road maintenance; charging of electric buses; etc

Faculty Members

• Pierre Flener (also see his homepage): CP, LS, applications
• María Andreína Francisco Rodríguez (also see her homepage): CP, applications
  
• Justin Pearson (also see his homepage): CP, LS, applications
  
• Di Yuan: MP, applications

Events

• We organise NordConsNet 2025, the 20th workshop of NordConsNet, the Nordic Network for researchers and practitioners of Constraint programming.
• We organised CPAIOR 2024, the 21st International Conference on the Integration of Constraint Programming, Artificial Intelligence, and Operations Research.
• We are the founding node of NordConsNet, the Nordic Network for researchers and practitioners of Constraint programming: if you want to be informed of its annual workshops, then sign up to its email list by contacting Justin Pearson.

Research Awards

• Gustav Björdal: Honorable Mention for the ACP Doctoral Research Award, 2023 (PhD dissertation)
• Mats Carlsson: ACP Research Excellence Award, 2023
• Lei You: INFORMS Telecommunications & Network Analytics Best Dissertation Award, 2020 (PhD dissertation)

Software

• Our GitHub repository, including our Atlantis CBLS backend to MiniZinc
• Our fzn-oscar-cbls backend to MiniZinc uses the solver OscaR.cbls
• Presolving through tabling, for MiniZinc
• Bounded-length string variables & constraints, for Gecode

Education

• 1DL451: Modelling for Combinatorial Optimisation (5 credits): CP, LS, MP, SAT, SMT
• 1DL481: Algorithms and Data Structures III (5 credits): LS, MP, SAT, SMT
  
• 1TD184: [Continuous] Optimisation (5 credits): MP
  

Work with Us

• All our PhD, postdoc, and researcher positions are announced at university level: monitor that link, and note that there is no yearly intake of PhD students at our department.
• We do not take any summer interns.