DSpace collection:
http://ria.ua.pt:80/handle/10773/5870
Fri, 02 Feb 2018 12:12:05 GMT2018-02-02T12:12:05ZColored Ray Configurations
http://ria.ua.pt:80/handle/10773/21978
title: Colored Ray Configurations
authors: Fabila, Ruy; Garcia, Alfredo; Hurtado, Ferran; Jaume, Rafel; Perez-Lantero, Pablo; Saumell, Maria; Silveira, Rodrigo; Tejel, Javier; Urrutia, Jorge
abstract: We study the cyclic sequences induced at infinity by pairwise-disjoint colored rays with apices on a given balanced
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 fixed point set. We also examine sequences
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 realizable from a given point set on a line or in convex position.Wed, 01 Jan 2014 00:00:00 GMThttp://ria.ua.pt:80/handle/10773/219782014-01-01T00:00:00ZA faster algorithm to compute the visibility map of a 1.5D terrain
http://ria.ua.pt:80/handle/10773/21971
title: A faster algorithm to compute the visibility map of a 1.5D terrain
authors: Loffler, Maarten; Saumell, M.; Silveira, Rodrigo
abstract: 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.Wed, 01 Jan 2014 00:00:00 GMThttp://ria.ua.pt:80/handle/10773/219712014-01-01T00:00:00ZRegion-based approximation of probability distributions (for visibility between imprecise points among obstacles)
http://ria.ua.pt:80/handle/10773/21863
title: Region-based approximation of probability distributions (for visibility between imprecise points among obstacles)
authors: Buchin, Kevin; Kostitsyna, Irina; Loffler, Maarten; Silveira, Rodrigo
abstract: Let p and q be two imprecise points, given as probability
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.Wed, 01 Jan 2014 00:00:00 GMThttp://ria.ua.pt:80/handle/10773/218632014-01-01T00:00:00ZA Tool for Visually Exploring Multi-objective Mixed-Integer Optimization Models
http://ria.ua.pt:80/handle/10773/21848
title: A Tool for Visually Exploring Multi-objective Mixed-Integer Optimization Models
authors: Lopes, Rui Borges; Sousa Santos, Beatriz; Ferreira, Carlos
abstract: Multi-objective optimization models have been increasingly used as optimal decisions are searched in settings considering several conflicting objectives. In these cases
compromises must be made and often a large number of nondominated optimal solutions exist. From these solutions decisionmakers must find the preferred one. This is a difficult task both from a computational and cognitive point of views, as it requires several solutions to be obtained and compared. An interactive
visualization tool for fully understanding the best trade-offs is
therefore becoming increasingly important. This paper proposes visualization solutions, implemented in a tool, for aiding decision-makers in finding the preferred solution in multiobjective optimization problems.Wed, 01 Jan 2014 00:00:00 GMThttp://ria.ua.pt:80/handle/10773/218482014-01-01T00:00:00Z