About
59
Publications
20,215
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
576
Citations
Introduction
Current institution
Additional affiliations
Universidad de Valladolid, Segovia, Spain
Position
- Professor (Associate)
Publications
Publications (59)
El Pensamiento Computacional ha irrumpido en el currículo de Educación Primaria y Secundaria, y resulta necesario disponer tanto de una aproximación teórica como de actividades prácticas para su correcta inclusión en las aulas. En este taller se presentan dos actividades prácticas de PC de suelo bajo y techo alto, que serán abordadas a través de la...
In the realm of K-12 Education, the growing significance of Computational Thinking has sparked extensive inquiry into its nature and instructional methodologies. Despite a wealth of literature on the subject, ongoing debates persist regarding its fundamental components. Across global educational landscapes, Computational Thinking is being incorpora...
Los objetivos de este trabajo son explorar el conocimiento especializado de estudiantes para maestro (EPM) en una tarea de pensamiento computacional (PC) e indagar sobre el encaje del PC dentro del modelo Mathematics Teacher’s Specialized Knowledge (MTSK). Para ello, los EPM escogieron una tarea Bebras y, mediante un cuestionario ad hoc, debieron e...
En este trabajo se explora la integración de los asis-tentes de IA en la asignatura de Programación Orien-tada a Objetos en el grado de Ingeniería Informática de Servicios y Aplicaciones de la Universidad de Vallado-lid desde el punto de vista de las percepciones de los estudiantes. Para ello, se anima a los estudiantes a uti-lizar los asistentes d...
El pensamiento computacional ha pasado a formar parte del currículo de matemáticas desde la última ley educativa. A partir de un breve cuestionario a los participantes de un curso de formación del profesorado, analizamos sus percepciones sobre el conocimiento y preparación para abordarlo de manera efectiva antes y después de recibir una formación e...
La reciente Ley Orgánica por la que se modifica la Ley Orgánica de Educación (LOMLOE) ha traído cambios significativos tanto en el diseño de las sesiones como en
el área de matemáticas. En este artículo presentamos el diseño de una situación de
aprendizaje según se define en la LOMLOE centrada en el desarrollo del sentido
estocástico y basada en lo...
La Consejería de Educación de la Junta de Castilla y León lanzó en 2018 su Plan para la Mejora de las Matemáticas (PMM), combinando de forma notable tres ingredientes que, cada día bajo un consenso más amplio, es imprescindible considerar en todo proyecto educativo de calidad, a saber: innovación, investigación y evaluación. En esta ponencia se pre...
The Singapore bar-model has recently arrived in many Spanish classrooms, where it has been
identified as an effective modelling tool for problem-solving in primary schools. This model
introduces a pictorial approach prior to the abstract symbolic resolution. Schools usually change
over to this scheme by introducing it in grade 1 (6/7 years old) and...
En esta comunicación se describen cinco propuestas de aula que nos pueden servir para apoyar la filosofía el diseño universal de aprendizaje, es decir, que pueden llevarse a cabo en cualquier aula pero, de manera específica, buscan favorecer el desarrollo matemático y la inclusión de las personas con dificultades de aprendizaje en matemáticas. Este...
Movilización del pensamiento estadístico en maestros. Propuesta de lectura más allá de los datos.
Loops are a rich source of parallelism. Unfortunately, many loops cannot be safely parallelized at compile time because the compiler is not able to guarantee that there will be no dependence violations. Thread-Level Speculation (TLS) techniques, either hardware or software-based, allow the parallel execution of non-analyzable loops, issuing the exe...
Reseña del libro "Aritmética para Maestros", escrito por Pedro Ramos Alonso
We present the first universal reconfiguration algorithm for transforming a modular robot between any two facet-connected square-grid configurations using pivot moves. More precisely, we show that five extra “helper” modules (“musketeers”) suffice to reconfigure the remaining n modules between any two given configurations. Our algorithm uses O(n2)\...
En este trabajo se presenta un ciclo de una investigación basada en diseño (DBR) en Atsiame, Ghana. Sobre una trayectoria hipotética de aprendizaje inicial, se llevan a cabo las de sesiones de intervención en las que, en microciclos de mejora diaria, se analizan los resultados y se rediseña, en caso de ser necesario, la intervención. Basándonos en...
Los metaanálisis sobre el uso de manipulativos, tanto físicos como virtuales, muestran que estos constituyen una ayuda eficaz en el aprendizaje de las matemáticas. En este artículo estudiamos el uso y eficacia de manipulativos dependiendo de variables como el tipo de tarea o la edad del niño. Se han seleccionado, en un entorno online, 1344 respuest...
We present the first universal reconfiguration algorithm for transforming a modular robot between any two facet-connected square-grid configurations using pivot moves. More precisely, we show that five extra "helper" modules ("musketeers") suffice to reconfigure the remaining $n$ modules between any two given configurations. Our algorithm uses $O(n...
In this work we propose two hybrid algorithms for the segmentation of color images in regions of quasi-homogeneous color. Our algorithms are based on two known segmentation algorithms, namely, region growing and run-length encoding. We have implemented our algorithms, and we have made a preliminary evaluation of their performance on three color ima...
El conocimiento matemático necesario para una buena docencia en matemáticas en Educación Primaria es un dominio cuya descripción, delimitación y comprensión facilita y orienta el diseño y el desarrollo de programas de formación inicial y permanente de maestros. En este trabajo se realiza una aproximación parcial al conocimiento común del contenido...
Natural growth processes tend to generate shapes in the form of imprecise planar tesselations, where the tiles do not match exactly and leave some space among them. In this paper we model these tesselations by means of Voronoi Diagrams. We look for the set of 2D-sites whose Voronoi Diagram better approximates the given imprecise tessellation. Since...
Natural growth processes tend to generate shapes in the form of imprecise planar tesselations, where the tiles do not match exactlyand leave some space among them. In this paper we model these tesselations by means of Voronoi Diagrams. We look for the set of 2D-sites whose Voronoi Diagram better approximates the given imprecise tessellation. Since...
Scheduling is one of the factors that most directly affect performance in Thread-Level Speculation (TLS). Since loops may present dependences that cannot be predicted before runtime, finding a good chunk size is not a simple task. The most used mechanism, Fixed-Size Chunking (FSC), requires many “dry-runs” to set the optimal chunk size. If the loop...
We study a class of geometric optimization problems closely related to the 2-center problem: Given a set S of n pairs of points, assign to each point a color (“red” or “blue”) so that each pair’s points are assigned different colors and a function of the radii of the minimum enclosing balls of the red points and the blue points, respectively, is op...
We propose algorithms for pricing a transportation network in such a way that the prot generated by the customers is maximized. We model the transportation network as a subset of the plane and take into account the fact that the customers minimize their own transportation cost. The un- derlying theory is a two-player game model called Stackel- berg...
En este trabajo utilizamos la técnica de la paralelización especulativa (también conocida como "paralelización optimista") para ejecutar automáticamente en paralelo un algoritmo secuencial con un patrón irregular de violaciones de dependencia. Nos centramos en un importante problema: la triangulación de Delaunay de un conjunto de puntos de dos dime...
A point q is embraced by a set of points S if q is interior to the convex hull of S [8]. In some illumination applications where points of S are lights and q is a point to be illuminated, the embracing concept is related to a good illumination [4, 6], also known as the ∆-guarding [12] and the well-covering [10]. In this paper, we are not only inter...
We study a new family of geometric graphs that interpolate between the Delaunay triangulation and the Gabriel graph. These graphs share many properties with β-skeletons for β ∈ [0, 1] (such as sublinear spanning ratio) with the added benefit of planarity (and consequently linear size and local routability). 1
We consider algorithms for finding the optimal location of a simple transportation device, that we call a moving walkway, consisting of a pair of points in the plane between which the travel speed is high. More specifically, one can travel from one endpoint of the walkway to the other at speed v>1, but can only travel at unit speed between any othe...
In this paper we consider a new time metric called the Heavy Luggage Metric. This metric models the behavior of a traveller in a city wishing to walk as little as possible, maybe carrying some very heavy luggage. A transportation network allows the traveller to move between any pair of stations at cost zero, while walking has a cost proportional to...
Filtering and clustering of the data are very important aspects in data visualization. We will concentrate on these two topics
and study how can we combine them to simulate a multiresolution scheme. We will focus on the properties of Voronoi Diagrams
in order to avoid the need to compute any other time- or space-consuming data structure. Voronoi Di...
A highway H is a line in the plane on which one can travel at a greater speed than in the remaining plane. One can choose to enter and exit H at any point. The highway time distance between a pair of points is the minimum time required to move from one point to the other, with optional use of H.The highway hullH(S,H) of a point set S is the minimal...
A highway H is a line in the plane on which one can travel at a greater speed than in the remaining plane. One can choose to enter and exit H at any point. The highway time distance between a pair of points is the minimum time required to move from one point to the other, with optional use of H. The highway hull HH(S,H) of a point set S is the mini...
Scheduling for speculative parallelization is a problem that remained unsolved despite its importance. Simple methods such as Fixed-Size Chunking (FSC) need several 'dry-runs' before an acceptable chunk size is found. Other traditional scheduling methods were originally designed for loops with no dependences, so they are primarily focused in the pr...
In this work, we address the problem of scheduling loops with dependences in the context of speculative parallelization. We show that the scheduling alternatives are highly influenced by the dependence violation pattern the code presents. We center our analysis in those algorithms where dependences are less likely to appear as the execution proceed...
We consider algorithms for finding the optimal location of a simple transportation device, that we call a moving walkway, consisting of a pair of points in the plane between which the travel speed is high. More specifically, one can travel from one endpoint of the walkway to the other at speedv > 1, but can only travel at unit speed between any oth...
A point p is 1-well illuminated by a set F of n point lights if p lies in the interior of the convex hull of F. This concept corresponds to triangle-guarding or well-covering. In this paper we consider the illumination range of the light sources as a parameter to be optimized. First, we solve the problem of minimizing the light sources' illuminatio...
High performance machines have become available nowadays to an increasing number of researchers. Most of us might have both an access to a supercomputing center and an algorithm that could benefit from these high performance machines. The aim of the present work is to revisit all existing parallelization alternatives, including emerging technologie...
This paper presents TPCC-UVa, an open-source implementation of the TPC-C benchmark intended to be used in parallel and distributed systems. TPCC-UVa is written entirely in C language and it uses the Post-greSQL database engine. This implementation includes all the functionalities described by the TPC-C standard specification for the measurement of...
Given n point sites in the plane each painted in one of k colors, the region of a c-colored site p in the Farthest Color Voronoi Diagram (FCVD) contains all points of the plane for which c is the farthest color and p the nearest c-colored site. This novel structure generalizes both the standard Voronoi diagram (k = 1) and the farthest site Voronoi...
Hoy en día es cada vez más fácil tener acceso a un supercomputador. Sin embargo sólo los programadores expertos, con un elevado conocimiento del problema a paralelizar y de la arquitectura de la máquina en que se desea ejecutar el programa, son capaces de diseñar algoritmos que se ejecuten en paralelo eficientemente. En este trabajo presentamos una...
In this work the authors addressed the problem of scheduling loops with dependencies in the context of speculative parallelization. It is shown that scheduling alternatives are highly influenced by the dependence violation pattern presented in the code. The analysis was centered in those algorithms where dependencies are less likely to appear as th...
Abstract The MIR Voronoi diagram appears with the notion of good illumination introduced in [3, 4]. This illumination concept,generalizes well-covering [7] and triangle guarding [9]. The MIR Voronoi diagram,merges the notions of proximity and convex dependency. Given a set S of planar light sources, for each point q in the plane we search for the s...
This article explores three basic approaches to parallelize the planar Convex Hull on computer clusters. Methods which are based on sorting the points are found to be inadequate for computer clusters due to the communication costs involved.
Finding the fastest algorithm to solve a problem is one of the main issues in Computational Geometry. Focusing only on worst
case analysis or asymptotic computations leads to the development of complex data structures or hard to implement algorithms.
Randomized algorithms appear in this scenario as a very useful tool in order to obtain easier imple...
The city Voronoi diagram is induced by quickest
paths in the L
1plane, made faster by an isothetic
transportation network. We investigate
the rich geometric and algorithmic properties of city Voronoi diagrams,
and report on their use in processing quickest-path queries.
In doing so, we revisit the fact that not every Voronoi-type
diagram has int...
We solve an interesting optimization problem motivated by tolerancing metrology, paper position sensing, and facility location: What rectangle fits best a given set of points? This problem has relations to the minimum width annulus problem and also to the largest empty rectangle problem for both of which O(n log n) time solutions are not known. Nev...
We are given a transportation line where displacements happen at a bigger speed than in the rest of the plane. A shortest time path is a path between two points which takes less than or equal time to any other. We consider the time to follow a shortest time path to be the time distance between the two points. In this paper, we give a simple algorit...
- [...]
A flipturn transforms a nonconvex simple polygon into another simple polygon by rotating a concavity 180° around the midpoint of its bounding convex hull edge. Joss and Shannon proved in 1973 that a sequence of flipturns eventually transforms any simple polygon into a convex polygon. This paper describes several new results about such flipturn sequ...
Motivated by questions in location planning, we show for a set of colored points in the plane how to compute the smallest (by perimeter or area) axis-parallel rectangle, the narrowest strip, and other smallest objects enclosing at least one site of each color.
In this paper we study several issues on proximity problems that arise when, starting with the L1 metric in the plane, an isothetic transportation network is introduced and a new metric is induced.
Abstract Given n point sites in the plane each painted in one of k colors, the region of a c-colored site p in the Farthest Color Voronoi Diagram (FCVD) contains all points of the plane for which c is the farthest color and p the nearest c-colored site. This novel structure generalizes both the standard Voronoi diagram (k = 1) and the farthest site...
This paper is concerned with a pivot of central concern in polymer physics research called a flipturn, first defined in an unpublished 1973 paper of Joss and Shannon [4] as follows. A pocket of a nonconvex polygon P is a maximal connected sequence of polygon edges disjoint from the convex hull of P except at its endpoints. The line segment joining...
A flipturn is an operation that transforms a nonconvex simple polygon into another simple polygon, by rotating a concavity 180 degrees around the midpoint of its bounding convex hull edge. Joss and Shannon proved in 1973 that a sequence of flipturns eventually transforms any simple polygon into a convex polygon. This paper describes several new res...
Resumen Los diagramas de Voronoi son teselaciones del plano basadas en el concepto de distancia. Numerosos autores han trabajado en el estudio de estos diagramas tanto para la m etrica eucl dea como para otras m etricas. En este trabajo se describen los diagramas de Voronoi dados por funciones temporales surgidas al introducir en el plano una red d...
