Now showing items 21-40 of 128

    • Bounds on the max and min bisection of random cubic and 4-regular graphs 

      Díaz Cort, Josep; Do, Norman; Serna Iglesias, María José; Wormald, Nick (2002-12)
      External research report
      Open Access
      In this paper we present simple randomized algorithms to bisect cubic and 4-regular graphs. These algorithms produce bisections of size asymptotically at most 0.17404n for typical random cubic n-vertex graphs, and ...
    • Celebrity games 

      Álvarez Faura, M. del Carme; Blesa Aguilera, Maria Josep; Duch Brown, Amalia; Messegué Buisan, Arnau; Serna Iglesias, María José (2016-10-04)
      Article
      Open Access
      We introduce Celebrity games, a new model of network creation games. In this model players have weights (W being the sum of all the player's weights) and there is a critical distance ß as well as a link cost a. The cost ...
    • Centrality measure in social networks based on linear threshold model 

      Riquelme Csori, Fabián; Gonzalez Cantergiani, Pablo; Molinero Albareda, Xavier; Serna Iglesias, María José (2018-01-15)
      Article
      Open Access
      Centrality and influence spread are two of the most studied concepts in social network analysis. In recent years, centrality measures have attracted the attention of many researchers, generating a large and varied number ...
    • Chromatic number in random scaled sector graphs 

      Díaz Cort, Josep; Sanwalani, Vishal; Serna Iglesias, María José; Spirakis, Paul George (2004-04)
      External research report
      Open Access
      In this paper, we introduce a new model of random graph that we call random sector graph. This model aims to provide a tool for studying communication problems in networks of sensors using laser communication such as ...
    • Coaching on new technologies: programming workshop on Android applications for Google phones 

      Blesa Aguilera, Maria Josep; Duch Brown, Amalia; Gabarró Vallès, Joaquim; Hernández, Hugo; Serna Iglesias, María José (2011-10)
      Article
      Restricted access - publisher's policy
      In this work we describe our experience teaching an innovative Android programming workshop organized by the Universitat Politècnica de Catalunya (UPC) within the AndroidEDU Google EMEA Program. The growing interest in ...
    • Communication tree problems 

      Álvarez Faura, M. del Carme; Cases Muñoz, Rafel; Díaz Cort, Josep; Petit Silvestre, Jordi; Serna Iglesias, María José (2001-03)
      External research report
      Open Access
      In this paper, we consider random communication requirements and several cost measures for a particular model of tree routing on a complete network. First we show that a random tree does not give any approximation. Then ...
    • Complexity issues on bounded restrictive H-coloring 

      Serna Iglesias, María José; Díaz Cort, Josep; Thilikos Touloupas, Dimitrios (2004-04)
      External research report
      Open Access
      We consider the restriction of the H-coloring problem where we are looking for homomorphisms were the number of preimages of certain vertices of H is bounded by some fixed constant. We consider the decision and the ...
    • Complexity of metric dimension on planar graphs 

      Díaz Cort, Josep; Pottonen, Ollie; Serna Iglesias, María José; van Leeuwen, Erik Jan (2017-04-03)
      Article
      Open Access
      The metric dimension of a graph G is the size of a smallest subset L ¿ V (G) such that for any x, y ¿ V (G) with x =/ y there is a z ¿ L such that the graph distance between x and z differs from the graph distance between ...
    • Computation of bisection width for random d-regular graphs 

      Díaz Cort, Josep; Serna Iglesias, María José; Wormald, Nick (2003-07)
      External research report
      Open Access
      In this paper we describe a randomized greedy algorithm for obtaining bisections of graphs. Analysis of the algorithm's performance on random d-regular graphs yields asymptotically almost sure upper bounds on the bisection ...
    • Continuous assessment in the evolution of a CS1 course: The pass rate/workload ratio 

      Blesa Aguilera, Maria Josep; Duch Brown, Amalia; Gabarró Vallès, Joaquim; Petit Silvestre, Jordi; Serna Iglesias, María José (Springer, 2016)
      Part of book or chapter of book
      Open Access
      The first programming course (Programming-1, CS1) in the Informatics Engineering Degree of the Facultat d'Informàtica de Barcelona was completely redesigned in 2006 in order to reinforce the learn-by- doing methodology. ...
    • Continuous monitoring in the dynamic sensor field model 

      Álvarez Faura, M. del Carme; Díaz Cort, Josep; Dieter Wilhelm, Mitsche; Serna Iglesias, María José (2011-05)
      External research report
      Open Access
      In this work we consider the problem of continuously monitoring a collection of data sets produced by sensors placed on moving or static targets. We propose a modification of the static sensor field model (SSSF) [2] to ...
    • Convergence theorems for some layout measures on random lattice and random geometric graphs 

      Díaz Cort, Josep; Penrose, Matthew; Petit Silvestre, Jordi; Serna Iglesias, María José (1999-04)
      External research report
      Open Access
      This work deals with convergence theorems and bounds on the cost of several layout measures for lattice graphs, random lattice graphs and sparse random geometric graphs. For full square lattices, we give optimal layouts ...
    • Cooperation through social influence 

      Molinero Albareda, Xavier; Riquelme Csori, Fabián; Serna Iglesias, María José (Elsevier, 2015-05-01)
      Article
      Open Access
      We consider a simple and altruistic multiagent system in which the agents are eager to perform a collective task but where their real engagement depends on the willingness to perform the task of other influential agents. ...
    • Counting H-colorings of partial k-trees 

      Díaz Cort, Josep; Serna Iglesias, María José; Thilikos Touloupas, Dimitrios (2000-11)
      External research report
      Open Access
      The problem of counting all H-colorings of a graph G of n vertices is considered. While the problem is, in general #P-complete, we give linear time algorithms that solve the main variants of this problem when the input ...
    • Counting list h-colorings and variants 

      Díaz Cort, Josep; Serna Iglesias, María José; Thilikos Touloupas, Dimitrios (2001-05)
      External research report
      Open Access
      We study the counting versions of several variants of the H-coloring problem. The complexity of the H-coloring problem is described by a dichotomy theorem that classifies the problem according to the the topology of H ...
    • Dimension and codimension of simple games 

      Kurz, Sascha; Molinero Albareda, Xavier; Olsen, Martin; Serna Iglesias, María José (2016-11-01)
      Article
      Open Access
      This paper studies the complexity of computing a representation of a simple game as the intersection (union) of weighted majority games, as well as, the dimension or the codimension. We also present some examples with ...
    • Economía aplicada al estudio de la evolución de un curso 

      Blesa Aguilera, Maria Josep; Duch Brown, Amalia; Gabarró Vallès, Joaquim; Petit Silvestre, Jordi; Serna Iglesias, María José (Asociación de Enseñantes Universitarios de la Informática (AENUI), 2017)
      Article
      Open Access
      In this paper we propose a method to quantitatively analyze the effectiveness of the different measures taken to improve a course’s evaluation process. Our proposal uses simple tools from economics and the social sciences. ...
    • Efficient algorithms for parameterized H-colorings 

      Díaz Cort, Josep; Serna Iglesias, María José; Thilikos Touloupas, Dimitrios (2005-12)
      External research report
      Open Access
      We study the fixed parameter tractability of the restrictive $H$-coloring and the restrictive list $H$-coloring problems, introduced in~cite{DST01b}. The parameterizations are defined by fixing the number of pre-images of ...
    • Els Límits de la computació : indecidibilitat i NP-completesa 

      Serna Iglesias, María José; Álvarez Faura, M. del Carme; Cases Muñoz, Rafel; Lozano Bojados, Antoni (Edicions UPC, 2001)
      Book
      Restricted access to the UPC academic community
      Aquest text presenta una introducció a les teories de la calculabilitat i la complexitat a l'abast d'un estudiant de primer cicle d'una enginyeria informàtica. A partir de la justificació de la necessitat d'un model formal ...
    • Faulty random geometric networks 

      Díaz Cort, Josep; Petit Silvestre, Jordi; Serna Iglesias, María José (2000-10)
      External research report
      Open Access
      In this paper we analyze the computational power of random geometric networks in the presence of random (edge or node) faults considering several important network parameters. We first analyze how to emulate an original ...