Now showing items 1-20 of 583

    • 3-colorability of pseudo-triangulations 

      Aichholzer, Oswin; Aurenhammer, Franz; Hackl, Thomas; Huemer, Clemens; Pilz, Alexander; Vogtenhuber, Birgit (2015)
      Article
      Open Access
      Deciding 3-colorability for general plane graphs is known to be an NP-complete problem. However, for certain families of graphs, like triangulations, polynomial time algorithms exist. We consider the family of pseudo-tri ...
    • 4-labelings and grid embeddings of plane quadrangulations 

      Barrière Figueroa, Eulalia; Huemer, Clemens (2009-06-03)
      External research report
      Open Access
      We show that each quadrangulation on $n$ vertices has a closed rectangle of influence drawing on the $(n-2) \times (n-2)$ grid. Further, we present a simple algorithm to obtain a straight-line drawing of a quadrangulation ...
    • A benchmark for graph neural networks for computer network modeling 

      Carol Bosch, Sergi (Universitat Politècnica de Catalunya, 2019-06-27)
      Master thesis
      Open Access
      Today, network operators still lack functional network models able to make accurate predictions of end-to-end Key Performance Indicators (e.g., delay).This thesis introduces the benchmark for computer network modeling using ...
    • A block algorithm for the algebraic path problem and its execution on a systolic array 

      Núñez, Fernando J.; Valero Cortés, Mateo (Institute of Electrical and Electronics Engineers (IEEE), 1989)
      Conference report
      Open Access
      The solution of the algebraic path problem (APP) for arbitrarily sized graphs by a fixed-size systolic array processor (SAP) is addressed. The APP is decomposed into two subproblems, and SAP is designed for each one. Both ...
    • A Boolean algebra approach to the construction of snarks 

      Fiol Mora, Miquel Àngel (John Wiley & Sons, 1991)
      Part of book or chapter of book
      Open Access
      This work deals with the construction of snarks, that is, cubic graphs that cannot be 3-edge-colored. A natural generalization of the concept of "color", that describes in a simple way the coloring ("0" or "1") of any set ...
    • A Constraint-Based Hypergraph Partitioning Approach to Coreference Resolution 

      Sapena Masip, Emilio; Padró, Lluís; Turmo Borras, Jorge (2013-12)
      Article
      Open Access
      This work is focused on research in machine learning for coreference resolution. Coreference resolution is a natural language processing task that consists of determining the expressions in a discourse that refer to the ...
    • A constraint-based hypergraph partitioning approach to coreference resolution 

      Sapena Masip, Emili (Universitat Politècnica de Catalunya, 2012-05-16)
      Doctoral thesis
      Open Access
      The objectives of this thesis are focused on research in machine learning for coreference resolution. Coreference resolution is a natural language processing task that consists of determining the expressions in a discourse ...
    • A construction of Small (q-1)-Regular Graphs of Girth 8 

      Abreu, Marien; Araujo Pardo, Gabriela; Balbuena Martínez, Maria Camino Teófila; Labbate, D. (2015-04-21)
      Article
      Open Access
      In this note we construct a new infinite family of (q - 1)-regular graphs of girth 8 and order 2q(q - 1)(2) for all prime powers q >= 16, which are the smallest known so far whenever q - 1 is not a prime power or a prime ...
    • A construction of small regular bipartite graphs of girth 8 

      Balbuena Martínez, Maria Camino Teófila (2009-01)
      Article
      Open Access
      Let q be a prime a power and k an integer such that 3 ≤ k ≤ q. In this paper we present a method using Latin squares to construct adjacency matrices of k-regular bipartite graphs of girth 8 on $2(kq^{2}-q)$ vertices. Some ...
    • A differential approach for bounding the index of graphs under perturbations 

      Dalfó Simó, Cristina; Fiol Mora, Miquel Àngel; Garriga Valle, Ernest (2011-09-02)
      Article
      Open Access
      This paper presents bounds for the variation of the spectral radius (G) of a graph G after some perturbations or local vertex/edge modifications of G. The perturbations considered here are the connection of a new vertex ...
    • A differential approach for bounding the index of graphs under perturbations 

      Dalfó Simó, Cristina; Fiol Mora, Miquel Àngel; Garriga Valle, Ernest (2011-03)
      External research report
      Open Access
    • A discussion on the design of graph database benchmarks 

      Domínguez Sal, David; Martínez Bazán, Norbert; Muntés Mulero, Víctor; Baleta Ferrer, Pedro; Larriba Pey, Josep (2011)
      Article
      Open Access
      Graph Database Management systems (GDBs) are gaining popularity. They are used to analyze huge graph datasets that are naturally appearing in many application areas to model interrelated data. The objective of this paper ...
    • A family of mixed graphs with large order and diameter 2 

      Araujo Pardo, Gabriela; Balbuena Martínez, Maria Camino Teófila; Miller, Mirka; Zdimalova, Maria (2017-02)
      Article
      Open Access
      A mixed regular graph is a connected simple graph in which each vertex has both a fixed outdegree (the same indegree) and a fixed undirected degree. A mixed regular graphs is said to be optimal if there is not a mixed ...
    • A framework for building OLAP cubes on graphs 

      Ghrab, Amine; Romero Moral, Óscar; Skhiri, Sabri; Vaisman, Alejandro; Zimányi, Esteban (Springer, 2015)
      Conference report
      Open Access
      Graphs are widespread structures providing a powerful abstraction for modeling networked data. Large and complex graphs have emerged in various domains such as social networks, bioinformatics, and chemical data. However, ...
    • A general method to obtain the spectrum and local spectra of a graph from its regular partitions 

      Dalfó Simó, Cristina; Fiol Mora, Miquel Àngel (2020-07-12)
      Article
      Open Access
      It is well known that, in general, part of the spectrum of a graph can be obtained from the adjacency matrix of its quotient graph given by a regular partition. In this paper, a method that gives all the spectrum, and also ...
    • A general model for performance optimization of sequential systems 

      Bufistov, Dmitry; Cortadella, Jordi; Kishinevsky, Michael; Sapatnekar, Sachin S. (Institute of Electrical and Electronics Engineers (IEEE), 2007)
      Conference report
      Open Access
      Retiming, c-slow retiming and recycling are different transformations for the performance optimization of sequential circuits. For retiming and c-slow retiming, different models that provide exact solutions have already ...
    • A graph semantics for a variant of the ambient calculus more adequate for modeling SOC 

      Mylonakis Pascual, Nicolás (2017-02-07)
      External research report
      Open Access
      In this paper we present a graph semantics of a variant of the well known ambient calculus. The main change of our variant is to extract the mobility commands of the original calculus from the ambient topology. Similar ...
    • A graph signal processing solution for defective directed graphs 

      Barrufet Ribes, Júlia (Universitat Politècnica de Catalunya, 2020-06-29)
      Bachelor thesis
      Open Access
      Covenantee:   USC Viterbi School of Engineering
      The main purpose of this thesis is to nd a method that allows to systematically adapt GSP techniques so they can be used on most non-diagonalizable graph operators. In Chapter 1 we begin by presenting the framework in ...
    • A logic of graph conditions extended with paths 

      Navarro Gomez, Marisa; Orejas Valdés, Fernando; Pino Blanco, Elvira; Lambers, Leen (2016)
      Conference report
      Open Access
      In this paper we tackle the problem of extending the logic of nested graph conditions with paths. This means, for instance, that we may state properties about the existence of paths between some given nodes. As a main ...
    • A logic of graph conditions extended with paths 

      Navarro Gomez, Marisa; Orejas Valdés, Fernando; Pino Blanco, Elvira; Lambers, Leen (2016)
      Conference report
      Open Access
      In this paper we tackle the problem of extending the logic of nested graph conditions with paths. This means, for instance, that we may state properties about the existence of paths between some given nodes. As a main ...