Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/3199
Tue, 17 Jan 2017 17:21:28 GMT2017-01-17T17:21:28ZRamsey numbers for empty convex polygons
http://hdl.handle.net/2117/85553
Ramsey numbers for empty convex polygons
Bautista-Santiago, Crevel; Cano, Javier; Fabila-Monroy, Ruy; Hidalgo-Toscano, Carlos; Huemer, Clemens; Leaños, Jesús; Sakai, Toshinori; Urrutia, Jorge
We study a geometric Ramsey type problem where the vertices of the complete graph Kn are placed on a set S of n points in general position in the plane, and edges are drawn as straight-line segments. We define the empty convex polygon Ramsey number REC (k, k) as the smallest number n such that for every set S of n points and for every two-coloring of the edges of Kn drawn on S, at least one color class contains an empty convex k-gon. A polygon is empty if it contains no points from S in its interior. We prove 17 ≤ REC (3, 3) ≤ 463 and 57 ≤ REC (4, 4). Further, there are three-colorings of the edges of Kn (drawn on a set S) without empty monochromatic triangles. A related Ramsey number for islands in point sets is also studied.
Tue, 12 Apr 2016 11:19:04 GMThttp://hdl.handle.net/2117/855532016-04-12T11:19:04ZBautista-Santiago, CrevelCano, JavierFabila-Monroy, RuyHidalgo-Toscano, CarlosHuemer, ClemensLeaños, JesúsSakai, ToshinoriUrrutia, JorgeWe study a geometric Ramsey type problem where the vertices of the complete graph Kn are placed on a set S of n points in general position in the plane, and edges are drawn as straight-line segments. We define the empty convex polygon Ramsey number REC (k, k) as the smallest number n such that for every set S of n points and for every two-coloring of the edges of Kn drawn on S, at least one color class contains an empty convex k-gon. A polygon is empty if it contains no points from S in its interior. We prove 17 ≤ REC (3, 3) ≤ 463 and 57 ≤ REC (4, 4). Further, there are three-colorings of the edges of Kn (drawn on a set S) without empty monochromatic triangles. A related Ramsey number for islands in point sets is also studied.On the disks with diameters the sides of a convex 5-gon
http://hdl.handle.net/2117/85548
On the disks with diameters the sides of a convex 5-gon
Huemer, Clemens; Pérez-Lantero, Pablo
We prove that for any convex pentagon there are two disks, among the five disks having a side of the pentagon as diameter and the midpoint of the side as its center, that do not intersect. This shows that K5 is never the intersection graph of such five disks.
Tue, 12 Apr 2016 10:55:15 GMThttp://hdl.handle.net/2117/855482016-04-12T10:55:15ZHuemer, ClemensPérez-Lantero, PabloWe prove that for any convex pentagon there are two disks, among the five disks having a side of the pentagon as diameter and the midpoint of the side as its center, that do not intersect. This shows that K5 is never the intersection graph of such five disks.Region-based approximation algorithms for visibility between imprecise locations
http://hdl.handle.net/2117/82487
Region-based approximation algorithms for visibility between imprecise locations
Buchin, Kevin; Kostitsyna, Irina; Löffler, Maarten; Silveira, Rodrigo Ignacio
In this paper we present new geometric algorithms for approximating the visibility between two imprecise locations amidst a set of obstacles, where the imprecise locations are modeled by continuous probability distributions. Our techniques are based on approximating distributions by a set of regions rather than on approximating by a discrete point sample. In this way we obtain guaranteed error bounds, and the results are more robust than similar results based on discrete point sets. We implemented our techniques and present an experimental evaluation. The experiments show that the actual error of our region-based approximation scheme converges quickly when increasing the complexity of the regions.
Wed, 03 Feb 2016 11:58:09 GMThttp://hdl.handle.net/2117/824872016-02-03T11:58:09ZBuchin, KevinKostitsyna, IrinaLöffler, MaartenSilveira, Rodrigo IgnacioIn this paper we present new geometric algorithms for approximating the visibility between two imprecise locations amidst a set of obstacles, where the imprecise locations are modeled by continuous probability distributions. Our techniques are based on approximating distributions by a set of regions rather than on approximating by a discrete point sample. In this way we obtain guaranteed error bounds, and the results are more robust than similar results based on discrete point sets. We implemented our techniques and present an experimental evaluation. The experiments show that the actual error of our region-based approximation scheme converges quickly when increasing the complexity of the regions.Las habilidades sociales del docente universitario: una formación hacia la competencia interpersonal
http://hdl.handle.net/2117/27666
Las habilidades sociales del docente universitario: una formación hacia la competencia interpersonal
Gómez Soberón, José Manuel Vicente; Berbegal Mirabent, Jasmina; Cañabate Carmona, Antonio; Farrerons Vidal, Óscar; Huerta Carrillo, María; Montero Mercadé, Lídia; Mora Giné, Mercè; Santos Boada, Germán; Torre Martínez, María del Rocío de la; Corral Manuel de Villena, Ignacio de
Desde el ICE de la UPC se ha planteado una nueva formación dirigida a todo el profesorado basada en la adquisición de competencias docentes. Uno de los módulos de formación puesto en marcha trabaja la adquisición de la competencia interpersonal. Hasta la fecha se han realizado dos cursos a lo largo del año 2013. En este artículo se detallan los contenidos tratados en el módulo y las experiencias desarrolladas por algunos de los profesores que lo pusieron en práctica.
Promoted by the ICE of the UPC has been set a new training for all teachers based on the acquisition of teaching skills. One of the started training modules works the acquirement of interpersonal competence. For the time being there have been two courses, both developed throughout 2013. This article describes the content covered in the module and the experiences which were carried out by some of the teachers who implemented it.
Wed, 29 Apr 2015 13:50:19 GMThttp://hdl.handle.net/2117/276662015-04-29T13:50:19ZGómez Soberón, José Manuel VicenteBerbegal Mirabent, JasminaCañabate Carmona, AntonioFarrerons Vidal, ÓscarHuerta Carrillo, MaríaMontero Mercadé, LídiaMora Giné, MercèSantos Boada, GermánTorre Martínez, María del Rocío de laCorral Manuel de Villena, Ignacio deDesde el ICE de la UPC se ha planteado una nueva formación dirigida a todo el profesorado basada en la adquisición de competencias docentes. Uno de los módulos de formación puesto en marcha trabaja la adquisición de la competencia interpersonal. Hasta la fecha se han realizado dos cursos a lo largo del año 2013. En este artículo se detallan los contenidos tratados en el módulo y las experiencias desarrolladas por algunos de los profesores que lo pusieron en práctica.
Promoted by the ICE of the UPC has been set a new training for all teachers based on the acquisition of teaching skills. One of the started training modules works the acquirement of interpersonal competence. For the time being there have been two courses, both developed throughout 2013. This article describes the content covered in the module and the experiences which were carried out by some of the teachers who implemented it.Colored Ray configurations
http://hdl.handle.net/2117/27279
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
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 bound on the number of color sequences that can be realized from any xed point set. We also examine se- quences that can be realized regardless of the point set and exhibit negative examples as well. In addition, we provide algorithms to decide whether a sequence is re- alizable from a given point set on a line or in convex position
Mon, 13 Apr 2015 11:28:47 GMThttp://hdl.handle.net/2117/272792015-04-13T11:28:47ZFabila Monroy, RuyGarcia Olaverri, Alfredo MartinHurtado Díaz, Fernando AlfredoJaume, RafelPérez Lantero, PabloSaumell, MariaSilveira, Rodrigo IgnacioTejel Altarriba, Francisco JavierUrrutia Galicia, JorgeWe 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 bound on the number of color sequences that can be realized from any xed point set. We also examine se- quences that can be realized regardless of the point set and exhibit negative examples as well. In addition, we provide algorithms to decide whether a sequence is re- alizable from a given point set on a line or in convex positionA faster algorithm to compute the visibility map of a 1.5D terrain
http://hdl.handle.net/2117/27275
A faster algorithm to compute the visibility map of a 1.5D terrain
Löffler, Maarten; Saumell, Maria; Silveira, Rodrigo Ignacio
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 from at least one of the viewpoints. We present an algorithm that runs in O ( n + m log m ) time. This improves over a previous algorithm recently proposed
Mon, 13 Apr 2015 11:14:57 GMThttp://hdl.handle.net/2117/272752015-04-13T11:14:57ZLöffler, MaartenSaumell, MariaSilveira, Rodrigo IgnacioGiven 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 from at least one of the viewpoints. We present an algorithm that runs in O ( n + m log m ) time. This improves over a previous algorithm recently proposedRegion-based approximation of probability distributions (for visibility between imprecise points among obstacles)
http://hdl.handle.net/2117/27274
Region-based approximation of probability distributions (for visibility between imprecise points among obstacles)
Buchin, Kevin; Kostitsyna, Irina; Löffler, Maarten; Silveira, Rodrigo Ignacio
Let p and q be two imprecise points, given as prob- ability density functions on R 2 , and let R be a set of n line segments in R 2 . We study the problem of approximating the probability that p and q can see each other; that is, that the segment connecting p and q does not cross any segment of R . To solve this problem, we approximate each density function by a weighted set of polygons; a novel approach to dealing with probability density functions in computational geometry
Mon, 13 Apr 2015 11:05:24 GMThttp://hdl.handle.net/2117/272742015-04-13T11:05:24ZBuchin, KevinKostitsyna, IrinaLöffler, MaartenSilveira, Rodrigo IgnacioLet p and q be two imprecise points, given as prob- ability density functions on R 2 , and let R be a set of n line segments in R 2 . We study the problem of approximating the probability that p and q can see each other; that is, that the segment connecting p and q does not cross any segment of R . To solve this problem, we approximate each density function by a weighted set of polygons; a novel approach to dealing with probability density functions in computational geometryOrder types and cross-sections of line arrangements in R^3
http://hdl.handle.net/2117/26484
Order types and cross-sections of line arrangements in R^3
Aichholzer, Oswin; Fabila-Monroy, Ruy; Hurtado Díaz, Fernando Alfredo; Pérez Lantero, Pablo; Ruiz Vargas, Andrés; Urrutia Galicia, Jorge; Vogtenhuber, Birgit
We consider sets L = {l1,...., ln} of n labeled lines in general position in R3, and study the order types of point sets fp1; : : : ; png that stem from the intersections of the lines in L with (directed) planes II, not parallel to any line of L, i.e., the proper cross-sections of L.
As a main result we show that the number of different order types that can be obtained as cross-sections of L is O(n9), and that this bound is tight.
Tue, 24 Feb 2015 12:06:32 GMThttp://hdl.handle.net/2117/264842015-02-24T12:06:32ZAichholzer, OswinFabila-Monroy, RuyHurtado Díaz, Fernando AlfredoPérez Lantero, PabloRuiz Vargas, AndrésUrrutia Galicia, JorgeVogtenhuber, BirgitWe consider sets L = {l1,...., ln} of n labeled lines in general position in R3, and study the order types of point sets fp1; : : : ; png that stem from the intersections of the lines in L with (directed) planes II, not parallel to any line of L, i.e., the proper cross-sections of L.
As a main result we show that the number of different order types that can be obtained as cross-sections of L is O(n9), and that this bound is tight.Geometric biplane graphs I: maximal graphs
http://hdl.handle.net/2117/26184
Geometric biplane graphs I: maximal graphs
Hurtado Díaz, Fernando Alfredo; Garcia Olaverri, Alfredo Martin; Korman Cozzetti, Matías; Matos, Inés P.; Saumell, Maria; Silveira, Rodrigo Ignacio; Tejel Altarriba, Francisco Javier; Tóth, Csaba D.
Mon, 02 Feb 2015 17:36:02 GMThttp://hdl.handle.net/2117/261842015-02-02T17:36:02ZHurtado Díaz, Fernando AlfredoGarcia Olaverri, Alfredo MartinKorman Cozzetti, MatíasMatos, Inés P.Saumell, MariaSilveira, Rodrigo IgnacioTejel Altarriba, Francisco JavierTóth, Csaba D.Geometric Biplane Graphs II: Graph Augmentation
http://hdl.handle.net/2117/26085
Geometric Biplane Graphs II: Graph Augmentation
Hurtado Díaz, Fernando Alfredo; Garcia Olaverri, Alfredo Martin; Korman Cozzetti, Matías; Matos, Inés P.; Saumell, Maria; Silveira, Rodrigo Ignacio; Tejel Altarriba, Francisco Javier; Tóth, Csaba D.
We study biplane graphs drawn on a nite point set
S
in the plane in general position.
This is the family of geometric graphs whose vertex set is
S
and which can be decomposed
into two plane graphs. We show that every su ciently large point set admits a 5-connected
biplane graph and that there are arbitrarily large point sets that do not admit any 6-
connected biplane graph. Furthermore, we show that every plane graph (other than a
wheel or a fan) can be augmented into a 4-connected biplane graph. However, there are
arbitrarily large plane graphs that cannot be augmented to a 5-connected biplane graph
by adding pairwise noncrossing edges.
Mon, 26 Jan 2015 19:01:27 GMThttp://hdl.handle.net/2117/260852015-01-26T19:01:27ZHurtado Díaz, Fernando AlfredoGarcia Olaverri, Alfredo MartinKorman Cozzetti, MatíasMatos, Inés P.Saumell, MariaSilveira, Rodrigo IgnacioTejel Altarriba, Francisco JavierTóth, Csaba D.We study biplane graphs drawn on a nite point set
S
in the plane in general position.
This is the family of geometric graphs whose vertex set is
S
and which can be decomposed
into two plane graphs. We show that every su ciently large point set admits a 5-connected
biplane graph and that there are arbitrarily large point sets that do not admit any 6-
connected biplane graph. Furthermore, we show that every plane graph (other than a
wheel or a fan) can be augmented into a 4-connected biplane graph. However, there are
arbitrarily large plane graphs that cannot be augmented to a 5-connected biplane graph
by adding pairwise noncrossing edges.