Now showing items 1-20 of 507

• #### 3-colorability of pseudo-triangulations ﻿

(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 ﻿

(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 ...
• #### Abelian Cayley digraphs with asymptotically large order for any given degree ﻿

(2016-04-29)
Article
Open Access
Abelian Cayley digraphs can be constructed by using a generalization to Z(n) of the concept of congruence in Z. Here we use this approach to present a family of such digraphs, which, for every fixed value of the degree, ...
• #### A benchmark for graph neural networks for computer network modeling ﻿

(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 ﻿

(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 ﻿

(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 ...
• #### About (k,l)-kernels, semikernels and Grundy functions in partial line digraphs ﻿

(2019-06)
Article
Open Access
Let D be a digraph of minimum in-degree at least 1. We prove that for any two natural numbers k, l such that 1 = l = k, the number of (k, l)-kernels of D is less than or equal to the number of (k, l)-kernels of any partial ...
• #### A Constraint-Based Hypergraph Partitioning Approach to Coreference Resolution ﻿

(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 construction of Small (q-1)-Regular Graphs of Girth 8 ﻿

(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 ﻿

(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 ...
• #### Active learning in Crowdsourcing classification problems using Sampling Theory for graph signals ﻿

(Universitat Politècnica de Catalunya, 2017-05-15)
Bachelor thesis
Open Access
Covenantee:  University of Southern California
• #### Acyclic edge colourings of graphs with large girth ﻿

(2016-11-03)
Article
Open Access
An edge colouring of a graph G is called acyclic if it is proper and every cycle contains at least three colours. We show that for every e > 0, there exists a g = g(e) such that if G has maximum degree ¿ and girth at least ...
• #### A differential approach for bounding the index of graphs under perturbations ﻿

(2011-03)
External research report
Open Access
• #### A differential approach for bounding the index of graphs under perturbations ﻿

(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 discussion on the design of graph database benchmarks ﻿

(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 ...
• #### Adjacency matrices of polarity graphs and of other C4-free graphs of large size ﻿

(2010)
Article
Restricted access - publisher's policy
In this paper we give a method for obtaining the adjacency matrix of a simple polarity graph $G_q$ from a projective plane PG(2,q), where q is a prime power. Denote by ex(n;C₄) the maximum number of edges of a graph on n ...
• #### A family of mixed graphs with large order and diameter 2 ﻿

(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 ﻿

(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, ...
• #### AGAMOS: A graph-based approach to modulo scheduling for clustered microarchitectures ﻿

(2009-06)
Article
Open Access
This paper presents AGAMOS, a technique to modulo schedule loops on clustered microarchitectures. The proposed scheme uses a multilevel graph partitioning strategy to distribute the workload among clusters and reduces the ...
• #### A general model for performance optimization of sequential systems ﻿

(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 ...