La exigua, desigual y menguante financiación de la universidad pública española (2009-2015)

Peer ReviewedPostprint (published version

A new meta-module for efficient reconfiguration of hinged-units modular robots

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 to the rotational degrees of freedom of these units, the novel meta-module is able to expand and contract, as to double/halve its length in each dimension. Moreover, for a large class of edge-hinged robots the proposed meta-module also performs the scrunch/relax and transfer operations required by any tunneling-based reconfiguration strategy, such as those designed for Crystalline and Telecube robots. These results make it possible to apply efficient geometric reconfiguration algorithms to this type of robots. We prove the size of this new meta-module to be optimal. Its robustness and performance substantially improve over previous results.Peer ReviewedPostprint (author's final draft

A new meta-module design for efficient reconfiguration of modular robots

This is a post-peer-review, pre-copyedit version of an article published in Autonomous Robots. The final authenticated version is available online at: http://dx.doi.org/10.1007/s10514-021-09977-6We propose a new meta-module design for two important classes of modular robots. The new metamodule is three-dimensional, robust and compact, improving on the previously proposed one. It applies to socalled “edge-hinged” modular robot units, such as MTRAN, SuperBot, SMORES, UBot, PolyBot and CKBot, as well as to so-called “central-point-hinged” modular robot units, which include Molecubes and Roombots. The new meta-module uses the rotational degrees of freedom of these two types of robot units in order to expand and contract, as to double or halve its length in each of the two directions of its three dimensions, therefore simulating the capabilities of Crystalline and Telecube robots. Furthermore, in the edge-hinged case we prove that the novel meta-module can also perform the scrunch, relax and transfer moves that are necessary in any tunnelingbased reconfiguration algorithm for expanding/contracting modular robots such as Crystalline and Telecube. This implies that the use of meta-meta-modules is unnecessary, and that currently existing efficient reconfiguration algorithms can be applied to a much larger set of modular robots than initially intended.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sk lodowska-Curie grant agreement No 734922. I.P. was supported by the Austrian Science Fund (FWF): W1230. V.S. and R.S. were supported by projects MINECO MTM2015-63791-R and Gen. Cat. 2017SGR1640. R.S. was also supported by MINECO through the Ram´on y Cajal program.Peer ReviewedPostprint (published version

Segmenting trajectories: A framework and algorithms using spatiotemporal criteria

In this paper we address the problem of segmenting a trajectory based on spatiotemporal criteria. We require that each segment is homogeneous in the sense that a set of spatiotemporal criteria are fulfilled. We define different such criteria, including location, heading, speed, velocity, curvature, sinuosity, curviness, and shape. We present an algorithmic framework that allows us to segment any trajectory into a minimum number of segments under any of these criteria, or any combination of these criteria. In this framework, a segmentation can generally be computed in O(n log n) time, where n is the number of edges of the trajectory to be segmented. We also discuss the robustness of our approach.Peer ReviewedPostprint (published version

Caminos de desviación mínima local

Un camino que conecta dos puntos s y t en el plano es de desviación mínima respecto de un conjunto de puntos S si la mayor de las distancias entre un punto del camino y S es la menor posible entre todos los caminos que conectan s y t. En este trabajo estudiamos los caminos de desviación mínima que satisfacen además que todo subcamino es también de desviación mínima, a los que llamamos caminos de desviación mínima local.Postprint (published version

Empty triangles in good drawings of the complete graph

A good drawing of a simple graph is a drawing on the sphere or, equivalently, in the plane in which vertices are drawn as distinct points, edges are drawn as Jordan arcs connecting their end vertices, and any pair of edges intersects at most once. In any good drawing, the edges of three pairwise connected vertices form a Jordan curve which we call a triangle. We say that a triangle is empty if one of the two connected components it induces does not contain any of the remaining vertices of the drawing of the graph. We show that the number of empty triangles in any good drawing of the complete graph Kn with n vertices is at least n.Peer ReviewedPostprint (author’s final draft

La pèrdua de paisatge en mosaic i d'eficiència metabòlica agrària a la Regió Metropolitana de Barcelona (1956-2009)

Els conceptes d'infraestructura verda i serveis ecosistèmics han emergit de manera simultània, i estan estretament interrelacionats. Entenem per infraestructura verda el conjunt d'àrees verdes urbanes, hortícoles, agrícoles, forestals i ramaderes que proporcionen un ampli ventall de serveis ecosistèmics a la ciutadania (MEA, 2005; Baró et al., 2016; Depietri et al., 206; Potschin-Young et al., 2018): de proveïment, de regulació i culturals o recreatius, que, al seu torn, requereixen el bon estat ecològic d'unes estructures biofísiques que els generen (i que se solen anomenar serveis ecosistèmics de suport) (...

Colored anchored visibility representations in 2D and 3D space

© 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/In a visibility representation of a graph G, the vertices are represented by nonoverlapping geometric objects, while the edges are represented as segments that only intersect the geometric objects associated with their end-vertices. Given a set P of n points, an Anchored Visibility Representation of a graph G with n vertices is a visibility representation such that for each vertex v of G, the geometric object representing v contains a point of P. We prove positive and negative results about the existence of anchored visibility representations under various models, both in 2D and in 3D space. We consider the case when the mapping between the vertices and the points is not given and the case when it is only partially given.Peer ReviewedPostprint (author's final draft

DVALon: una herramienta para diagramas de Voronoi y grafos de proximidad de alcance limitado

Presentamos un estudio de los diagramas de Voronoi de alcance limitado de un conjunto finito de puntos del plano y DVALon, una herramienta para la manipulaci´on de dichos diagramas, los grafos de proximidad de alcance limitado y su aplicación a los caminos de desviación mínima y de separación máxima.Postprint (published version

Simulating distributed algorithms for lattice agents

We present a practical Java tool for simulating synchronized distributed algorithms on sets of 2-and 3-dimensional square/cubic lattice-based agents. This AgentSystem assumes that each agent is capable to change position in the lattice and that neighboring agents can attach and detach from each other. In addition, it assumes that each module has some constant size memory and computation capability, and can send/receive constant size messages to/from its neighbors. The system allows the user to dene sets of agents and sets of rules and apply one to the other. The AgentSystem simulates the synchronized execution of the set of rules by all the modules, and can keep track of all actions made by the modules at each step, supporting consistency warnings and error checking. Our intention is to provide a useful tool for the researchers from geometric distributed algorithms.European Science FoundationAustrian Science FundMinisterio de Economía y CompetitividadMinisterio de Ciencia e Innovació