Enviaments recents

  • Refinement by browsing: an alternative to thumbnails 

    Gabarró Vallès, Joaquim; Vallejo, Isabel; Xhafa Xhafa, Fatos; Stewart, Alan; Clint, Maurice (2005-03)
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    Thumbnails are widely used in image retrieval and browsing systems. The use of such images compacts information. However, in situations where there are a large number of images on a server site, the use of thumbnails may ...
  • On Berners-Lee computer, hints on navigability semantics and lack of referential integrity 

    Gabarró Vallès, Joaquim; Vallejo, Isabel; Xhafa Xhafa, Fatos (2005-03)
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    In this paper we deal with semantics issues related to the stability, navigability and extensibility of web applications. To this end, we define a web application as a deterministic labelled transition system in which ...
  • A skeleton for the Tabu search metaheuristic with applications to problems in software engineering 

    Blesa Aguilera, Maria Josep; Xhafa Xhafa, Fatos (2001-06)
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    We present a C++ implementation of a skeleton for Tabu Search method. Tabu Search method is a well-known meta-heuristic that has proved successful for sub-optimally solving hard combinatorial optimization problems. Recently ...
  • Network creation games: structure vs anarchy 

    Álvarez Faura, M. del Carme; Messegué Buisan, Arnau (2017-09-03)
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    We study Nash equilibria and the price of anarchy in the classical model of Network Creation Games introduced by Fabrikant et al. In this model every agent (node) buys links at a prefixed price a > 0 in order to get connected ...
  • Examples of CF-bi-inmune and CF-levelable sets in LOGSPACE 

    Balcázar Navarro, José Luis; Díaz Cort, Josep; Gabarró Vallès, Joaquim (1984)
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    We find sets in the class LOGSPACE (on-line) that do not have good respectively approximations by context-free languages. For that we introduce the languages CF-bi-inmune and CF-levelable. We prove the results by defining ...
  • Connections among non uniform models for problems requiring high amount of resources 

    Balcázar Navarro, José Luis; Gabarró Vallès, Joaquim (1985-11)
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    We characterize in terms of oracle Turing machines the classes defined by exponential lower bounds on some nonuniform complexity measures. After, we use the same methods to give a new characterization of classes defined ...
  • Complements des facteurs gauches de mots infinis et ambiguité : quelques exemples 

    Autebert, Jean-Michel; Gabarró Vallès, Joaquim (1985)
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    On se propose d'utiliser la méthode que P. Flajolet a décrit pour prouver l'ambiguité du langage de Goldstine [5], afin de prouver l'ambiguité d'une série de langages du même type. Ces langages sont tous des complémentaires ...
  • On some "non uniform" complexity measures 

    Balcázar Navarro, José Luis; Díaz Cort, Josep; Gabarró Vallès, Joaquim (1985)
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    Non-uniform complexity measures origined in Automata and Formal Languages Theory are characterized in terms of well-known uniform complexity classes. The initial index of languages is introduced by means of several ...
  • Dos problemas 

    Gabarró Vallès, Joaquim (1985-09)
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  • About log-on languages : preliminary version 

    Cases Muñoz, Rafael; Gabarró Vallès, Joaquim (1985)
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    We deal with on-line log-space Turing Machines with markers in the work tapes. In this type of machines we prove the existence of a language L satisfying L ϵ NSPACE_s (log⁡ n) , L ̅ ϵ NSPACE_s (log⁡ n) and L ϵ NSPACE_s ...
  • Uniform characterizations of non-uniform complexity measures 

    Balcázar Navarro, José Luis; Díaz Cort, Josep; Gabarró Vallès, Joaquim (1985)
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    The class PSPACE/ply of sets decided within polynomial space by machines with polynomial advices is characterized in several way: we give an algebraic characterization, a parallel model characterization. Finally we define ...
  • Keeping control transfer instructions out of the pipeline in architectures without condition codes 

    Cortadella, Jordi; Llaberia Griñó, José M.; González Colás, Antonio María (1987-05)
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    The execution of branch instructions involves a loss of performance in pipelined processors. In this paper we present a mechanism for executing this kind of instruction with a zero delay. This mechanism has been proposed ...

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