Now showing items 1-9 of 9

    • Automatically improving constraint models in Savile Row 

      Nightingale, Peter; Akgün, Özgür; Gent, Ian P.; Jefferson, Christopher; Miguel, Ian; Spracklen, Patrick (2017-10) - Journal article
      When solving a combinatorial problem using Constraint Programming (CP) or Satisfiability (SAT), modelling and formulation are vital and difficult tasks. Even an expert human may explore many alternatives in modelling a ...
    • Breaking conditional symmetry in automated constraint modelling with CONJURE 

      Akgün, Özgür; Gent, Ian; Jefferson, Chris; Miguel, Ian; Nightingale, Peter (IOS Press, 2014) - Book item
      Many constraint problems contain symmetry, which can lead to redundant search. If a partial assignment is shown to be invalid, we are wasting time if we ever consider a symmetric equivalent of it. A particularly important ...
    • Exploiting short supports for improved encoding of arbitrary constraints into SAT 

      Akgün, Özgür; Gent, Ian Philip; Jefferson, Christopher Anthony; Miguel, Ian James; Nightingale, Peter William (Springer, 2016) - Conference item
      Encoding to SAT and applying a highly efficient modern SAT solver is an increasingly popular method of solving finite-domain constraint problems. In this paper we study encodings of arbitrary constraints where unit propagation ...
    • Extensible automated constraint modelling via refinement of abstract problem specifications 

      Akgün, Özgür (University of St Andrews, 2014-06-25) - Thesis
      Constraint Programming (CP) is a powerful technique for solving large-scale combinatorial (optimisation) problems. Constraint solving a given problem proceeds in two phases: modelling and solving. Effective modelling has ...
    • How people visually represent discrete constraint problems 

      Zhu, Xu; Nacenta, Miguel; Akgün, Özgür; Nightingale, Peter William (2019-01-24) - Journal article
      Problems such as timetabling or personnel allocation can be modeled and solved using discrete constraint programming languages. However, while existing constraint solving software solves such problems quickly in many cases, ...
    • Memory consistency models using constraints 

      Akgün, Özgür; Hoffmann, Ruth; Sarkar, Susmit (2018-08-27) - Conference item
      Memory consistency models (MCMs) are at the heart of concurrent programming. They represent the behaviour of concurrent programs at the chip level. To test these models small program snippets called litmus test are generated, ...
    • Modelling Langford's Problem : a viewpoint for search 

      Akgün, Özgür; Miguel, Ian (2018-08-27) - Conference item
      The performance of enumerating all solutions to an instance of Langford's Problem is sensitive to the model and the search strategy. In this paper we compare the performance of a large variety of models, all derived from ...
    • Solving computational problems in the theory of word-representable graphs 

      Akgün, Özgür; Gent, Ian P.; Kitaev, Sergey; Zantema, Hans (2019-02-24) - Journal article
      A simple graph G = (V, E) is word-representable if there exists a word w over the alphabet V such that letters x and y alternate in w iff xy ∈ E. Word-representable graphs generalize several important classes of graphs. A ...
    • Using metric space indexing for complete and efficient record linkage 

      Akgün, Özgür; Dearle, Alan; Kirby, Graham Njal Cameron; Christen, Peter (Springer, 2018) - Conference item
      Record linkage is the process of identifying records that refer to the same real-world entities, in situations where entity identifiers are unavailable. Records are linked on the basis of similarity between common attributes, ...