Now showing items 1-20 of 48

  • Adjacency-preserving spatial treemaps 

    Buchin, Kevin; Eppstein, David; Löffler, Maarten; Nöllenburg, Martin; Silveira, Rodrigo Ignacio (2016)
    Article
    Open Access
    Rectangular layouts, subdivisions of an outer rectangle into smaller rectangles, have many applications in visualizing spatial information, for instance in rectangular cartograms in which the rectangles represent geographic ...
  • A faster algorithm to compute the visibility map of a 1.5D terrain 

    Löffler, Maarten; Saumell, Maria; Silveira, Rodrigo Ignacio (2014)
    Conference report
    Open Access
    Given a 1.5D terrain, i.e., an x -monotone polygonal line in R 2 with n vertices, and 1 m n viewpoints placed on some of the terrain vertices, we study the problem of computing the parts of the terrain that are visible ...
  • A new lower bound on the maximum number of plane graphs using production matrices 

    Huemer, Clemens; Pilz, Alexander; Silveira, Rodrigo Ignacio (2018)
    Conference lecture
    Restricted access - publisher's policy
    We use the concept of production matrices to show that there exist sets of n points in the plane that admit ¿(41.77n) crossing-free geometric graphs. This improves the previously best known bound of ¿(41.18n) by Aichholzer ...
  • A new meta-module for efficient reconfiguration of hinged-units modular robots 

    Parada, Irene; Sacristán Adinolfi, Vera; Silveira, Rodrigo Ignacio (Institute of Electrical and Electronics Engineers (IEEE), 2016)
    Conference report
    Open Access
    We present a robust and compact meta-module for edge-hinged modular robot units such as M-TRAN, SuperBot, SMORES, UBot, PolyBot and CKBot, as well as for central-point-hinged ones such as Molecubes and Roombots. Thanks ...
  • A note on flips in diagonal rectangulations 

    Cardinal, Jean; Sacristán Adinolfi, Vera; Silveira, Rodrigo Ignacio (Chapman & Hall/CRC, 2018-11-09)
    Article
    Open Access
    Rectangulations are partitions of a square into axis-aligned rectangles. A number of results provide bijections between combinatorial equivalence classes of rectangulations and families of pattern-avoiding permutations. ...
  • Balanced partitions of 3-colored geometric sets in the plane 

    Bereg, Sergey; Hurtado Díaz, Fernando Alfredo; Kano, Mikio; Korman, Matias; Lara, Dolores; Seara Ojea, Carlos; Silveira, Rodrigo Ignacio; Urrutia Galicia, Jorge; Verbeek, Kevin (2015)
    Article
    Open Access
    Let SS be a finite set of geometric objects partitioned into classes or colors . A subset S'¿SS'¿S is said to be balanced if S'S' contains the same amount of elements of SS from each of the colors. We study several ...
  • Cell-paths in mono- and bichromatic line arrangements in the plane 

    Aichholzer, Oswin; Cardinal, Jean; Hackl, Thomas; Hurtado Díaz, Fernando Alfredo; Korman Cozzetti, Matías; Pilz, Alexander; Silveira, Rodrigo Ignacio; Uehara, Ryuhei; Vogtenhuber, Birgit; Welzl, Emo (2014)
    Conference report
    Open Access
    We show that in every arrangement of n red and blue lines | in general position and not all of the same color | there is a path through a linear number of cells where red and blue lines are crossed alternatingly (and no ...
  • Characteristic polynomials of production matrices for geometric graphs 

    Huemer, Clemens; Pilz, Alexander; Seara Ojea, Carlos; Silveira, Rodrigo Ignacio (2017-08-01)
    Article
    Open Access
    An n×n production matrix for a class of geometric graphs has the property that the numbers of these geometric graphs on up to n vertices can be read off from the powers of the matrix. Recently, we obtained such production ...
  • Colored Ray configurations 

    Fabila Monroy, Ruy; Garcia Olaverri, Alfredo Martin; Hurtado Díaz, Fernando Alfredo; Jaume, Rafel; Pérez Lantero, Pablo; Saumell, Maria; Silveira, Rodrigo Ignacio; Tejel Altarriba, Francisco Javier; Urrutia Galicia, Jorge (2014)
    Conference report
    Open Access
    We study the cyclic sequences induced at in nity by pairwise-disjoint colored rays with apices on a given bal- anced bichromatic point set, where the color of a ray is inherited from the color of its apex. We derive a lower ...
  • Colored ray configurations 

    Fabila Monroy, Ruy; Garcia Olaverri, Alfredo Martin; Hurtado Díaz, Fernando Alfredo; Jaume, Rafel; Pérez Lantero, Pablo; Saumell, Maria; Silveira, Rodrigo Ignacio; Tejel Altarriba, Francisco Javier; Urrutia Galicia, Jorge (2018-05)
    Article
    Open Access
    We study the cyclic color sequences induced at infinity by colored rays with apices being a given balanced finite bichromatic point set. We first study the case in which the rays are required to be pairwise disjoint. We ...
  • Colored spanning graphs for set visualization 

    Hurtado Díaz, Fernando Alfredo; Korman, Matias; Van Kreveld, Matias; Löffler, Maarten; Sacristán Adinolfi, Vera; Shioura, Akiyoshi; Silveira, Rodrigo Ignacio; Speckmann, Bettina; Tokuyama, Takeshi (2018-03)
    Article
    Open Access
    We study an algorithmic problem that is motivated by ink minimization for sparse set visualizations. Our input is a set of points in the plane which are either blue, red, or purple. Blue points belong exclusively to the ...
  • Colored spanning graphs for set visualization 

    Hurtado Díaz, Fernando Alfredo; Korman Cozzetti, Matías; Van Kreveld, Matias; Löffler, Maarten; Sacristán Adinolfi, Vera; Silveira, Rodrigo Ignacio; Speckmann, Bettina (Springer, 2013)
    Conference report
    Open Access
    We study an algorithmic problem that is motivated by ink minimization for sparse set visualizations. Our input is a set of points in the plane which are either blue, red, or purple. Blue points belong exclusively to the ...
  • Computing a visibility polygon using few variables 

    Barba, Luis; Korman Cozzetti, Matías; Langerman, Stefan; Silveira, Rodrigo Ignacio (2014-10-01)
    Article
    Restricted access - publisher's policy
    We present several algorithms for computing the visibility polygon of a simple polygon P of n vertices (out of which r are reflex) from a viewpoint inside P, when P resides in read-only memory and only few working variables ...
  • Computing correlation between piecewise-linear functions 

    Agarwal, Pankaj; Aronov, Boris; Van Kreveld, Matias; Löffler, Maarten; Silveira, Rodrigo Ignacio (2013)
    Article
    Restricted access - publisher's policy
    We study the problem of computing correlation between two piecewise-linear bivariate functions defined over a common domain, where the surfaces they define in three dimensions---polyhedral terrains---can be transformed ...
  • Computing optimal shortcuts for networks 

    Garijo Royo, Delia; Marquez Pérez, Alberto; Rodríguez, Natalia; Silveira, Rodrigo Ignacio (2018)
    Conference report
    Open Access
    We augment a plane Euclidean network with a segment or shortcut to minimize the largest distance between any two points along the edges of the resulting network. In this continuous setting, the problem of computing distances ...
  • Computing optimal shortcuts for networks 

    Garijo Royo, Delia; Marquez Pérez, Alberto; Rodríguez, Natalia; Silveira, Rodrigo Ignacio (2018)
    Conference report
    Open Access
    We study augmenting a plane Euclidean network with a segment, called shortcut, to minimize the largest distance between any two points along the edges of the resulting network. Questions of this type have received considerable ...
  • Computing similarity between piecewise-linear functions 

    Agarwal, Pankaj; Aronov, Boris; Kreveld, Marc van; Löffler, Maarten; Silveira, Rodrigo Ignacio (ACM Press. Association for Computing Machinery, 2010)
    Conference report
    Open Access
    We study the problem of computing the similarity between two piecewise-linear bivariate functions de ned over a common domain, where the surfaces they de ne in 3D|polyhedral terrains|can be transformed vertically by a ...
  • Connect the dot: computing feed-links for network extension 

    Speckmann, Bettina; Silveira, Rodrigo Ignacio; Aronov, Boris; Buchin, Kevin; Buchin, Maike; Jansen, Bart; De Jong, Tom; Kreveld, Marc van; Loffler, Maarten; Luo, Jun (2011-12-20)
    Article
    Open Access
    Road network analysis can require distance from points that are not on the network themselves. We study the algorithmic problem of connecting a point inside a face (region) of the road network to its boundary while ...
  • Flow computations on imprecise terrains 

    Driemel, Anne; Haverkort, Herman; Löffler, Maarten; Silveira, Rodrigo Ignacio (Springer Verlag, 2011)
    Conference report
    Restricted access - confidentiality agreement
    We study water flow computation on imprecise terrains. We consider two approaches to modeling flow on a terrain: one where water flows across the surface of a polyhedral terrain in the direction of steepest descent, and ...
  • Flow computations on imprecise terrains 

    Driemel, Anne; Haverkort, Herman; Löffler, Maarten; Silveira, Rodrigo Ignacio (2013)
    Article
    Open Access
    We study water flow computation on imprecise terrains. We consider two approaches to modeling flow on a terrain: one where water flows across the surface of a polyhedral terrain in the direction of steepest descent, and ...