Now showing items 1-20 of 126

    • A Characterization of universal stability for directed graphs in the adversarial queueing model 

      Álvarez Faura, M. del Carme; Blesa Aguilera, Maria Josep; Serna Iglesias, María José (2002-01)
      External research report
      Open Access
      In this paper we provide a characterization of universal stability for digraphs in the general case that the packets are not restricted to follow simple paths. Furthermore, we consider a variation of the Nearest To Go ...
    • A Characterization of universal stability in the adversarial queuing model 

      Serna Iglesias, María José; Blesa Aguilera, Maria Josep; Álvarez Faura, M. del Carme (2003-10)
      External research report
      Open Access
      We study universal stability of directed and undirected graphs in the adversarial queueing model for static packet routing. In this setting, packets are injected in some edge and have to traverse a predefined path before ...
    • A Constructive linear time algorithm for small cutwidth 

      Thilikos Touloupas, Dimitrios; Serna Iglesias, María José; Bodlaender, Hans L. (2000-09)
      External research report
      Open Access
      The cutwidth of a graph G is defined to be the smallest integer k such that the vertices of G can be arranged in a linear layout [v(1),...,v(n)] in such a way that for every i=1,...,n-1, there are at most k edges with the ...
    • A cost-benefit analysis of continuous assessment 

      Duch Brown, Amalia; Gabarró Vallès, Joaquim; Petit Silvestre, Jordi; Blesa Aguilera, Maria Josep; Serna Iglesias, María José (SciTePress, 2015)
      Conference report
      Open Access
      The first course on programming is fundamental in the Facultat d’Informàtica de Barcelona. After a major redesign of the Programming-1 course in 2006 to give it a more practical flavor, an increasing number of measures ...
    • A list of parameterized problems in bioinformatics 

      Félix Ávila, Liliana; García Chacón, Alina; Serna Iglesias, María José; Thilikos Touloupas, Dimitrios (2006-05)
      External research report
      Open Access
      In this report we present a list of problems that originated in bionformatics. Our aim is to collect information on such problems that have been analyzed from the point of view of Parameterized Complexity. For every problem ...
    • A Polynomial time algorithm for the cutwidth of bounded degree graphs with small treewidth 

      Thilikos Touloupas, Dimitrios; Serna Iglesias, María José; Bodlaender, Hans L. (2001-02)
      External research report
      Open Access
      The cutwidth of a graph G is defined to be the smallest integer k such that the vertices of G can be arranged in a vertex ordering [v(1),...,v(n)] in a way that, for every i=1,...,n-1, there are at most k ...
    • A Random graph model for optical networks of sensors 

      Díaz Cort, Josep; Petit Silvestre, Jordi; Serna Iglesias, María José (2002-12)
      External research report
      Open Access
      In this paper we propose a model for Smart Dust Networks and show its applicability when the goal of the network is monitoring an area under the surveillance of a base station. We analyze basic parameters of these nets and ...
    • A Survey on graph layout problems 

      Díaz Cort, Josep; Petit Silvestre, Jordi; Serna Iglesias, María José (2000-10)
      External research report
      Open Access
      In this paper we survey results on several graph layout problems from an algorithmic point of view. Graph layout problems are a particular class of combinatorial optimization problems whose goal is to find a linear layout ...
    • Absorption time of the Moran process 

      Díaz Cort, Josep; Goldberg, Leslie Ann; Richerby, David; Serna Iglesias, María José (2016-08-01)
      Article
      Open Access
      © 2016 Wiley Periodicals, Inc. The Moran process models the spread of mutations in populations on graphs. We investigate the absorption time of the process, which is the time taken for a mutation introduced at a randomly ...
    • Adversarial models for priority-based networks 

      Álvarez Faura, M. del Carme; Díaz Cort, Josep; Blesa Aguilera, Maria Josep; Fernández Anta, Antonio; Serna Iglesias, María José (2003-06)
      External research report
      Open Access
      We propose several variations of the adversarial queueing model. The priority model takes into account the case in which the packets can have different priorities, assigned by the adversary at injection time. The ...
    • Adversarial queueing model for continuous network dynamics 

      Blesa Aguilera, Maria Josep; Calzada, Daniel; Fernández Anta, Antonio; López, Luís; Martínez Fernández, Andrés; Santos, Agustín; Serna Iglesias, María José (2005-05)
      External research report
      Open Access
      In this paper we start the study of generalizing the Adversarial Queueing Theory (AQT) model towards a continuous scenario in which the usually assumed synchronicity of the evolution is not required anymore. We consider a ...
    • Algorítmica per a paral·lelisme massiu : introducció 

      Díaz Cort, Josep; Serna Iglesias, María José (Edicions UPC, 1999)
      Book
      Restricted access to the UPC academic community
      Aquest llibre és una introducció al disseny d’algorismes paral·lels per a màquines síncrones. Als capítols 1-5 es presenten els conceptes bàsics del disseny d’algorismes per a xarxes d’interconexió: vectors, meshes, meshes ...
    • An angel-daemon approach to assess the uncertainty in the power of a collectivity to act 

      Fragnito, Giulia; Gabarró Vallès, Joaquim; Serna Iglesias, María José (Springer, 2017)
      Conference report
      Open Access
      We propose the use of the angel-daemon framework to assess the Coleman's power of a collectivity to act under uncertainty in weighted voting games. In this framework uncertainty profiles describe the potential changes ...
    • Analysing web-orchestrations under stress using uncertainty profiles 

      Gabarró Vallès, Joaquim; Serna Iglesias, María José; Stewart, Alan (Wiley Heyden, 2014-11-01)
      Article
      Open Access
      An orchestration is a multi-threaded computation that invokes a number of remote services. In practice, the responsiveness of a web-service fluctuates with demand; during surges in activity service responsiveness may be ...
    • Análisis de la evolución de un curso: productividad y desigualdad 

      Blesa Aguilera, Maria Josep; Duch Brown, Amalia; Gabarró Vallès, Joaquim; Petit Silvestre, Jordi; Serna Iglesias, María José (Universidad de Almería, 2016-07-05)
      Conference lecture
      Open Access
      Este trabajo analiza cuantitativamente las diferentes medidas adoptadas en la evaluación contínua del curso de Programación-1 de la Facultat d’Informàtica de Barcelona de la Universitat Politècnica de Catalunya desde 2010, ...
    • Approximating layout problems on random sparse graphs 

      Díaz Cort, Josep; Petit Silvestre, Jordi; Serna Iglesias, María José; Trevisan, Marco (1998-07)
      External research report
      Open Access
      We show that, with high probability, several layout problems are approximable within a constant for random graphs drawn from the standard Gnp model with p=c/n for some constant c. Our results establish that, in fact, ...
    • Approximating scheduling problems in parallel 

      Serna Iglesias, María José; Xhafa Xhafa, Fatos (1997-04)
      External research report
      Open Access
      We show how to approximate in NC the problem of Scheduling Unrelated Parallel Machines, for a fixed number of machines. We develop a (2+epsilon)-approximate parallel algorithm for the problem. Our approach shows how to ...
    • Approximating the permanent is in RNC 

      Díaz Cort, Josep; Serna Iglesias, María José; Spirakis, Paul George (1995-04)
      External research report
      Open Access
      In this work we look into the parallelization (in the NC sense) of the Markov Chain approach to almost random generation, as described by Sinclair (1993). We give a RNC almost uniform generator for perfect matchings in ...
    • Bisection of random cubic graphs 

      Díaz Cort, Josep; Do, Norman; Serna Iglesias, María José; Wormald, Nick (2002-05)
      External research report
      Open Access
      In this paper we present two randomized algorithms to compute the bisection width of random cubic graphs with n vertices, giving an asymptotic upper bound for the bisection width respectively of 0.174039n and 0.174501n. ...
    • Bounds on the bisection width for random d-regular graphs 

      Díaz Cort, Josep; Serna Iglesias, María José; Wormald, Nick (2004-04)
      External research report
      Open Access
      In this paper we provide an explicit way to compute asymptotically almost sure upper bounds on the bisection width of random d-regular graphs, for any value of d. The upper bounds are obtained from the analysis of the ...