Now showing items 1-15 of 15

    • Automatic evaluation of context-free grammars (system description) 

      Creus López, Carles; Godoy Balil, Guillem (Springer, 2014)
      Conference report
      Restricted access - publisher's policy
      We implement an online judge for context-free grammars. Our system contains a list of problems describing formal languages, and asking for grammars generating them. A submitted proposal grammar receives a verdict of ...
    • Automatic evaluation of reductions between NP-complete problems 

      Creus López, Carles; Fernández Durán, Pau; Godoy Balil, Guillem (Springer, 2014)
      Conference report
      Restricted access - publisher's policy
      We implement an online judge for evaluating correctness of reductions between NP-complete problems. The site has a list of exercises asking for a reduction between two given problems. Internally, the reduction is evaluated ...
    • Decidable classes of tree automata mixing local and global constraints modulo flat theories 

      Barguño, Luis; Creus López, Carles; Godoy Balil, Guillem; Jacquemard, Florent; Vacher, Camile (2013-02)
      Article
      Open Access
      We define a class of ranked tree automata TABG generalizing both the tree automata with local tests between brothers of Bogaert and Tison (1992) and with global equality and disequality constraints (TAGED) of Filiot et al. ...
    • Emptiness and finiteness for tree automata with global reflexive disequality constraints 

      Creus López, Carles; Gascón Caro, Adrià; Godoy Balil, Guillem (2013-12-01)
      Article
      Restricted access - publisher's policy
      In recent years, several extensions of tree automata have been considered. Most of them are related with the capability of testing equality or disequality of certain subterms of the term evaluated by the automaton. In ...
    • Excessively duplicating patterns represent non-regular languages 

      Creus López, Carles; Godoy Balil, Guillem; Ramos Garrido, Lander (2014-03-01)
      Article
      Restricted access - publisher's policy
      A constrained term pattern s:¿ represents the language of all instances of the term s satisfying the constraint ¿. For each variable in s, this constraint specifies the language of its allowed substitutions. Regularity of ...
    • Interactive inspection of complex multi-object industrial assemblies 

      Argudo Medrano, Óscar; Besora Vilardaga, Isaac; Brunet Crosa, Pere; Creus López, Carles; Hermosilla Casajús, Pedro; Navazo Álvaro, Isabel; Vinacua Pla, Álvaro (2016-10-01)
      Article
      Open Access
      The use of virtual prototypes and digital models containing thousands of individual objects is commonplace in complex industrial applications like the cooperative design of huge ships. Designers are interested in selecting ...
    • La realidad virtual en el aprendizaje de historia mediante la interacción con humanoides virtuales 

      Muñoz, Albert; Besora Vilardaga, Isaac; Creus López, Carles; Pelechano Gómez, Núria; Brunet Crosa, Pere; Beacco Porres, Alejandro (2009)
      Conference report
      Open Access
      La realidad virtual ofrece la posibilidad de interactuar de manera inmersiva en mundos virtuales 3D. Estos mundos virtuales pueden ser representaciones de otros momentos históricos que permiten al usuario explorar los ...
    • Learning theory through videos: a teaching experience in a theoretical course based on self-learning videos and problem-solving sessions 

      Arias Vicente, Marta; Creus López, Carles; Gascón Caro, Adrià; Godoy Balil, Guillem (SciTePress, 2011)
      Conference report
      Restricted access - publisher's policy
      In this paper we describe a teaching experience applied to a theoretical course tought in a computer science degree. The main feature of our experiment is the introduction of videos specifically designed for self-learning ...
    • Non-linear rewrite closure and weak normalization 

      Creus López, Carles; Godoy Balil, Guillem; Massanes Basi, Francesc d'Assis; Tiwari, Ashish Kumar (2013-10)
      Article
      Restricted access - publisher's policy
      A rewrite closure is an extension of a term rewrite system with new rules, usually deduced by transitivity. Rewrite closures have the nice property that all rewrite derivations can be transformed into derivations of a ...
    • R4: Realistic rain rendering in realtime 

      Creus López, Carles; Patow, Gustavo Ariel (2013-02)
      Article
      Restricted access - publisher's policy
      Realistic rain simulation is a challenging problem due to the variety of different phenomena to consider. In this paper we propose a new rain rendering algorithm that extends present state of the art in the field, achieving ...
    • Real-time Realistic Rain Rendering 

      Creus López, Carles (Universitat Politècnica de Catalunya, 2010-06-23)
      Master thesis
      Open Access
      Artistic outdoor filming and rendering need to choose specific weather conditions in order to properly trigger the audience reaction; for instance, rain, one of the most common conditions, is usually employed to transmit ...
    • The HOM problem is EXPTIME-complete 

      Creus López, Carles; Gascon Caro, Adrian; Godoy Balil, Guillem; Ramos Garrido, Lander (2016)
      Article
      Open Access
      We define a new class of tree automata with constraints and prove decidability of the emptiness problem for this class in exponential time. As a consequence, we obtain several EXPTIME-completeness results for problems on ...
    • The HOM problem is EXPTIME-complete 

      Creus López, Carles; Gascón Caro, Adrià; Godoy Balil, Guillem; Ramos, Lander (2012)
      Conference report
      Restricted access - publisher's policy
      The HOM problem questions whether the image of a given regular tree language through a given tree homomorphism is also regular. Decidability of HOM is an important theoretical question which was open for a long time. ...
    • Tree automata with constraints and tree homomorphisms 

      Creus López, Carles (Universitat Politècnica de Catalunya, 2016-05-24)
      Doctoral thesis
      Open Access
      Automata are a widely used formalism in computer science as a concise representation for sets. They are interesting from a theoretical and practical point of view. This work is focused on automata that are executed on ...
    • Tree automata with height constraints between brothers 

      Creus López, Carles; Godoy Balil, Guillem (Springer, 2014)
      Conference report
      Restricted access - publisher's policy
      We define the tree automata with height constraints between brothers (TACBB H ). Constraints of equalities and inequalities between heights of siblings that restrict the applicability of the rules are allowed in TACBB H. ...