Optimal Morphs of Convex Drawings

We give an algorithm to compute a morph between any two convex drawings of the same plane graph. The morph preserves the convexity of the drawing at any time instant and moves each vertex along a piecewise linear curve with linear complexity. The linear bound is asymptotically optimal in the worst case.Comment: To appear in SoCG 201

Un sitio web para la aproximación fenomenológica de la enseñanza de la luz y la visión

Presentamos las características de una página web sobre «Luz y visión» que diseñamos y preparamos para profesores (desde parvulario a 4º de ESO) con la intención de guiarlos por un itinerario desde el conocimiento que da el sentido común hasta la física. Además de experimentos y modelos interpretativos de fenomenología básica, proponemos ejemplos de trabajos realizados en escuelas por profesores (en parvularios y escuelas primarias y secundarias) en colaboración con nuestro grupo de investigación. La página fue desarrollada en el marco del proyecto italiano SeCiF (Spiegare e Capire in Fisica - Explicar y comprender en física) dedicado a preparar materiales (principalmente materiales de página web y redes telemáticas) para la formación de profesores en servicio y futuros profesores sobre una enseñanza innovadora de la física desde el parvulario a la escuela secundaria.We will present the characteristics of a Web site about «Light and Vision» we designed and prepared for teachers (of grades K-10) with the aim to drive them along a path from commonse knowledge to physics. In addition to experiments and interpretive models of basic phenomenology we propose examples of works made in schools by teachers (in some kindergarten, primary and secondary school classes) working with our research group. The site was developed inside of the Italian project SeCiF (Spiegare e Capire in Fisica - Explaining and Understanding in Physics) devoted to prepare materials (mainly Web materials and telematic networks) for in service and future teachers training about an innovative teaching of physics from kindergarten to secondary school

Relaxing the Constraints of Clustered Planarity

In a drawing of a clustered graph vertices and edges are drawn as points and curves, respectively, while clusters are represented by simple closed regions. A drawing of a clustered graph is c-planar if it has no edge-edge, edge-region, or region-region crossings. Determining the complexity of testing whether a clustered graph admits a c-planar drawing is a long-standing open problem in the Graph Drawing research area. An obvious necessary condition for c-planarity is the planarity of the graph underlying the clustered graph. However, such a condition is not sufficient and the consequences on the problem due to the requirement of not having edge-region and region-region crossings are not yet fully understood. In order to shed light on the c-planarity problem, we consider a relaxed version of it, where some kinds of crossings (either edge-edge, edge-region, or region-region) are allowed even if the underlying graph is planar. We investigate the relationships among the minimum number of edge-edge, edge-region, and region-region crossings for drawings of the same clustered graph. Also, we consider drawings in which only crossings of one kind are admitted. In this setting, we prove that drawings with only edge-edge or with only edge-region crossings always exist, while drawings with only region-region crossings may not. Further, we provide upper and lower bounds for the number of such crossings. Finally, we give a polynomial-time algorithm to test whether a drawing with only region-region crossings exist for biconnected graphs, hence identifying a first non-trivial necessary condition for c-planarity that can be tested in polynomial time for a noticeable class of graphs

Uplink Sounding Reference Signal Coordination to Combat Pilot Contamination in 5G Massive MIMO

To guarantee the success of massive multiple-input multiple-output (MIMO), one of the main challenges to solve is the efficient management of pilot contamination. Allocation of fully orthogonal pilot sequences across the network would provide a solution to the problem, but the associated overhead would make this approach infeasible in practical systems. Ongoing fifth-generation (5G) standardisation activities are debating the amount of resources to be dedicated to the transmission of pilot sequences, focussing on uplink sounding reference signals (UL SRSs) design. In this paper, we extensively evaluate the performance of various UL SRS allocation strategies in practical deployments, shedding light on their strengths and weaknesses. Furthermore, we introduce a novel UL SRS fractional reuse (FR) scheme, denoted neighbour-aware FR (FR-NA). The proposed FR-NA generalizes the fixed reuse paradigm, and entails a tradeoff between i) aggressively sharing some UL SRS resources, and ii) protecting other UL SRS resources with the aim of relieving neighbouring BSs from pilot contamination. Said features result in a cell throughput improvement over both fixed reuse and state-of-the-art FR based on a cell-centric perspective

Tracking deformable objects with WISARD networks

In this paper, we investigate a new approach based on WISARD Neural Network for the tracking of non-rigid deformable object. The proposed approach allows deploying an on–line training on the texture and shape features of the object, to adapt in real–time to changes, and to partially cope with occlusions. Moreover, the use of parallel classificatory trained on the same set of images allows tracking the movements of the objects. We evaluate our tracking abilities in the scenario of pizza making that represents a very challenging benchmark to test the approach since in this context the shape of the object to track completely changes during the manipulation