Ara es mostren els items 76-94 de 94

    • Random geometric problems on $[0,1]^2$ 

      Díaz Cort, Josep; Petit Silvestre, Jordi; Serna Iglesias, María José (1998-09)
      Report de recerca
      Accés obert
      In this paper we survey the work done for graphs on random geometric models. We present some heuristics for the problem of the Minimal Linear Arrangement on [0,1]^2 and we conclude with a collection of open problems.
    • Recent developments in structural complexity 

      Díaz Cort, Josep; Cucker Farkas, J.F. (1988)
      Report de recerca
      Accés obert
      This survey presents some of the recent developments in the field of structural complexity. The survey does not intend to give an exhaustive look in each one of the areas of structural complexity which have been developed ...
    • Recent results on parameterized H-coloring 

      Díaz Cort, Josep; Serna Iglesias, María José; Thilikos Touloupas, Dimitrios (2002-03)
      Report de recerca
      Accés obert
      We survey recent results on the complexity of several versions of the H-coloring and the list-H-coloring problems that are amenable to parameterization.
    • Reconstruction of random geometric graphs: breaking the Ω(r) distortion barrier 

      Dani, Varsha; Díaz Cort, Josep; Hayes, Thomas P.; Moore, Cristopher (2023-10-03)
      Article
      Accés obert
      Embedding graphs in a geographical or latent space, i.e. inferring locations for vertices in Euclidean space or on a smooth manifold or submanifold, is a common task in network analysis, statistical inference, and graph ...
    • Sampling matchings in parallel 

      Díaz Cort, Josep; Serna Iglesias, María José; Spirakis, Paul George (1998-03)
      Report de recerca
      Accés obert
      We present a parallel algorithm to sample matchings from an almost uniform distribution on the set of matchings of all sizes in a graph. The technique used is based on the definition of a genetic system that converges ...
    • Sequential and parallel complexity of learning DFA 

      Balcázar Navarro, José Luis; Díaz Cort, Josep; Gavaldà, Ricard (Universitat Politècnica de Catalunya. Departament de Llenguatges i Sistemes Informàtics, 1993)
      Text en actes de congrés
      Accés obert
      It is known that the class of deterministic finite automata is polynomial time learnable by using membership and equivalence queries. We investigate the query complexity of learning deterministic finite automata, i.e., ...
    • Simulation of complicated queries by membership queries 

      Díaz Cort, Josep; Watanabe, Osamu (1990)
      Report de recerca
      Accés obert
      In this paper, we consider the following type of learning: a teacher has some set, which is called a (target) concept, in his mind, and a learner tries to obtain the representation of the concept by asking queries on it ...
    • Some remarks on the approximability of graph layout problems 

      Díaz Cort, Josep; Serna Iglesias, María José; Spirakis, Paul George (1994-03)
      Report de recerca
      Accés obert
      In this paper we look at several well known layout problems. We show that MINCUT layout and Topological bandwidth cannot be approximated unless P=NP, whereas the Maximum linear arrangement problem can be approximated within ...
    • SPALINET: Red Española de lidares de aerosoles 

      Guerrero Ruiz, A.; Sicard, Michaël; Rocadenbosch Burillo, Francisco; Muñoz, C.; Tomás Martínez, Sergio; Comerón Tejero, Adolfo; Pujadas, Manuel; Molero, Francisco; Alados Arboledas, Lucas; Moreno, J. M.; Bolarín, Jose Miguel; Requena, Alberto; Córdoba Jabonero, Carmen; Gil, Marisa; Exposito, Francisco Javier; Díaz Cort, Josep; Pedrós, Roberto; Martínez Lozano, José Antonio (2008)
      Text en actes de congrés
      Accés restringit per política de l'editorial
    • Statistics on random trees 

      Cases Muñoz, Rafel; Díaz Cort, Josep; Martínez Parra, Conrado (1991-04-02)
      Report de recerca
      Accés obert
      In this paper we give a survey of the symbolic operator methods to do statistics on random trees. We present some examples and apply the techniques to find their asymptotic behaviour.
    • The Complexity of deciding stability under FFS in the adversarial model 

      Álvarez Faura, M. del Carme; Blesa Aguilera, Maria Josep; Díaz Cort, Josep; Fernández Anta, Antonio; Serna Iglesias, María José (2003-04)
      Report de recerca
      Accés obert
      In this paper we show the polynomial time decidability of the stability property under FFS in the case that the adversary can solve ties arbitrarily. This results follows from a characterization of the stability property ...
    • The Complexity of restrictive H-coloring 

      Díaz Cort, Josep; Serna Iglesias, María José; Thilikos Touloupas, Dimitrios (2002-03)
      Report de recerca
      Accés obert
      We define a variant of the H-coloring problem where the number of preimages of certain vertices is predetermined as part of the problem input. We consider the decision and the counting version of the problem, namely ...
    • The Hanoi's lectures 

      Díaz Cort, Josep (1985)
      Report de recerca
      Accés obert
      This set of notes are the core of the lectures given at the Department of Systems theory and Optimal Control in the Institute of Computer Science and Cybernetics of Hanoi, in June of 1985. They are incomplete, and form ...
    • The MINSUMCUT problem 

      Díaz Cort, Josep; Gibbons, Alan M.; Paterson, Michael Stewart; Torán Romero, Jacobo (1991-01)
      Report de recerca
      Accés obert
      In this paper we first present a sequential linear algorithm for an linear arrangement problem on trees, the MINSUMCUT, and then a 0(log n) time parallel algorithm for the MINSUMCUT on trees, which uses n [super 2]/(log ...
    • The multicolored graph realization problem 

      Díaz Cort, Josep; Yasar Diner, Oznur; Serna Iglesias, María José; Serra Albó, Oriol (Elsevier, 2022-07-01)
      Article
      Accés obert
      We introduce the multicolored graph realization problem (MGR). The input to this problem is a colored graph (G, φ), i.e., a graph G together with a coloring φ on its vertices. We associate each colored graph (G, φ) with a ...
    • The social cost of congestion games by imposing variable delays 

      Díaz Cort, Josep; Giotis, Ioannis; Kirousis, Lefteris; Mourtos, Ioannis; Serna Iglesias, María José (2017-12-01)
      Article
      Accés obert
      In this study, we describe a new coordination mechanism for non-atomic congestion games that leads to a (selfish) social cost which is arbitrarily close to the non-selfish optimal. This mechanism incurs no additional cost, ...
    • Theoretical aspects of graph models for MANETS 

      Díaz Cort, Josep; Dieter Wilhelm, Mitsche; Santi, Paolo (2010-03-01)
      Report de recerca
      Accés obert
      We survey the main theoretical aspects of models for Mobile Ad Hoc Networks (MANETs). We present theoretical characterizations of mobile network structural properties, di erent dynamic graph models of MANETs, and nally ...
    • Turing's algorithmic lens: from computability to complexity theory 

      Díaz Cort, Josep; Torras, Carme (2013)
      Article
      Accés obert
      The decidability question, i.e., whether any mathematical statement could be computationally proven true or false, was raised by Hilbert and remained open until Turing answered it in the negative. Then, most efforts in ...
    • Uniform characterizations of non-uniform complexity measures 

      Balcázar Navarro, José Luis; Díaz Cort, Josep; Gabarró Vallès, Joaquim (1985)
      Report de recerca
      Accés obert
      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 ...