Accurate video object tracking using a region-based particle filter

Usually, in particle filters applied to video tracking, a simple geometrical shape, typically an ellipse, is used in order to bound the object being tracked. Although it is a good tracker, it tends to a bad object representation, as most of the world objects are not simple geometrical shapes. A better way to represent the object is by using a region-based approach, such as the Region Based Particle Filter (RBPF). This method exploits a hierarchical region based representation associated with images to tackle both problems at the same time: tracking and video object segmentation. By means of RBPF the object segmentation is resolved with high accuracy, but new problems arise. The object representation is now based on image partitions instead of pixels. This means that the amount of possible combinations has now decreased, which is computationally good, but an error on the regions taken for the object representation leads to a higher estimation error than methods working at pixel level. On the other hand, if the level of regions detail in the partition is high, the estimation of the object turns to be very noisy, making it hard to accurately propagate the object segmentation. In this thesis we present new tools to the existing RBPF. These tools are focused on increasing the RBPF performance by means of guiding the particles towards a good solution while maintaining a particle filter approach. The concept of hierarchical flow is presented and exploited, a Bayesian estimation is used in order to assign probabilities of being object or background to each region, and the reduction, in an intelligent way, of the solution space , to increase the RBPF robustness while reducing computational effort. Also changes on the already proposed co-clustering in the RBPF approach are proposed. Finally, we present results on the recently presented DAVIS database. This database comprises 50 High Definition video sequences representing several challenging situations. By using this dataset, we compare the RBPF with other state-ofthe- art methods

A remark on the Brylinski conjecture for orbifolds

We present reformulation of Mathieu's result on representing cohomology classes of symplectic manifold with symplectically harmonic forms. We apply it to the case of foliated manifolds with transversally symplectic structure and to symplectic orbifolds. We obtain in particular that such representation is always possible for compact K\"{a}hler orbifolds.Comment: 10 page

Lleis de Kepler i mesura del temps

Les lleis de Kepler són les que governen el moviment dels planetes entorn del Sol. Johannes Kepler (1571-1630) les va obtenir de les dades observacionals de la posició dels planetes. Les dues primeres lleis (basades en l'observació del planeta Mart) estan contingudes en la seva obra Astronomia Nova publicada el 1609. En canvi, la tercera va ser obtinguda molt més tard. Està continguda en els tres volums de la seva obra Epitome Astronomia Copernicanae que van aparèixer entre 1617 i 1620. Gairebé un segle després Newton va utilitzar aquestes lleis basades en l'observació directa dels planetes per formular la seva llei de gravitació universal, de la qual les de Kepler es poden deduir. Aquest camp deductiu és el que seguirem en aquest escrit. Les tres lleis de Kepler, però, no donen explícitament la posició d'un planeta en la seva òrbita en cada instant de temps. Per obtenir això s'ha de resoldre el que es coneix amb el nom d'equació de Kepler, que potser és la primera equació important no algebraic

Mathematics in Catalonia : 1990-1996

The aim of this article is to present the main conclusions of the Report on research in Catalonia for the area of mathematics. The report was prepared by Joaquim Bruna, Marta Sanz, Joan de Solà-Morales and the author of this text, and published by the Institute for Catalan Studies in 1998. In the report, scientific activity in the area of mathematics was measured essentially by examining two parameters: papers published in specialised journals and doctoral theses read. It should be recognised that a considerable amount of activity in the field of mathematics consists of applying existing knowledge to the resolution of practical technological problems that arise in particular companies. This kind of scientific activity was not measured in any way in the report due to the difficulty of obtaining objective data. This article is divided into the following sections: human resources, scientific production, funding, research publications, research centres, and conclusions

A Neurocognitive Approach to the Study of Private Speech

The paper presents the current state of the art of research identifying the neurophysiological and neuroanatomical substrates of private speech, both in typical and clinical (or atypical) populations. First, it briefly describes the evolution of private speech research, which goes from classic traditions as the naturalistic and referential paradigms to the neurocognitive approach. An overview of the neurophysiological (e.g., event-related potentials or ERPs) and neuroimaging techniques (e.g., functional magnetic resonance imaging or fMRI) is also presented. The next three sections review empirical works about the neurocognitive basis of private speech, across three groups of techniques: ERPs; fMRI/MRI; and other neuroimaging techniques (positron emission tomography [PET], magnetoencephalogram [MEG], and repetitive transcranial magnetic stimulation [rTMS]). Such neurocognitive research analyzes the neural activity of individuals during a variety of task settings, including spontaneous and instructed overt and inner private speech use, subvocal verbalizations, and silent and overt reading. The fifth section focuses on electrophysiological and neuroimaging studies of private speech in atypical populations, for example: schizophrenia, pure alexia, hearing impairment, blindness, social phobia, alexithymia, Parkinson, and multiple sclerosis. The neurocognitive study of the various forms of private speech appears to be very promising in the understanding of these pathologies. Lastly, the advances and new challenges in the field are discussed.Este trabajo presenta el estado actual de la investigación que identifica los sustratos neurofisiológicos y neuroanatómicos del lenguaje privado, tanto en poblaciones típicas como en clínicas (o atípicas). Primero describe brevemente la evolución de la investigación del lenguaje privado, que van desde las tradiciones clásicas como los paradigmas naturalistas y referenciales al abordaje neurocognitivo. También se presenta una revisión de las técnicas neurofisiológicas (por ejemplo, potenciales relacionados con eventos o ERPs) y de neuroimagen (por ejemplo, imagen de resonancia magnética funcional o fMRI). Las siguientes tres secciones revisan los trabajos empíricos sobre la base neurocognitiva del lenguaje privado a través de tres grupos de técnicas: ERPs; fMRI/MRI; y otras técnicas de neuroimagen (tomografía de emisión de positrones [PET], magnetoencefalograma [MEG] y la estimulación magnética repetitiva transcraneal [rTMS]). Esta investigación neurocognitiva analiza la actividad neuronal de los individuos durante diversas tareas, incluyendo el uso del lenguaje privado espontáneo y observable bajo instrucciones y el lenguaje privado interno, las verbalizaciones subvocales y la lectura silenciosa y observable. La quinta sección se centra en los estudios electrofisiológicos y de neuroimágenes del lenguaje privado en poblaciones atípicas, por ejemplo, esquizofrenia, alexia pura, hipoacusia, ceguera, fobia social, alexithymia, Parkinson, y esclerosis múltiple. El estudio neurocognitivo de varias formas del lenguaje privado parece muy prometedor para la comprensión de estas patologías. Por último, se comentan los avances y los nuevos retos en el campo

Backscatter Transponder Based on Frequency Selective Surface for FMCW Radar Applications

This paper describes an actively-controlled frequency selective surface (FSS) to implement a backscatter transponder. The FSS is composed by dipoles loaded with switching PIN diodes. The transponder exploits the change in the radar cross section (RCS) of the FSS with the bias of the diodes to modulate the backscattered response of the tag to the FMCW radar. The basic operation theory of the system is explained here. An experimental setup based on a commercial X-band FMCW radar working as a reader is proposed to measure the transponders. The transponder response can be distinguished from the interference of non-modulated clutter, modulating the transponder’s RCS. Some FSS with different number of dipoles are studied, as a proof of concept. Experimental results at several distances are provided

Relojes de sol

¿Os habéis detenido alguna vez a pensar en la aparente simplicidad de un reloj de sol? Unas líneas dibujadas sobre una pared o en el suelo, un objeto que hace sombra, y nada más. Sin embargo un instrumento tan simple puede llegar a marcar la hora con un error inferior a un minuto, y puede indicarnos también con asombrosa precisión los días de cambio de estación (equinoccios y solsticios). Todo el conocimiento de la órbita terrestre (leyes de Kepler), todo el conocimiento de la astronomía de posición se hallan encerrados en el dibujo de las líneas de un reloj de sol

Optimization of the operation of smart rural grids through a novel rnergy management system

The paper proposes an innovative Energy Management System (EMS) that optimizes the grid operation based on economic and technical criteria. The EMS inputs the demand and renewable generation forecasts, electricity prices and the status of the distributed storages through the network, and solves with an optimal quarter-hourly dispatch for controllable resources. The performance of the EMS is quantified through diverse proposed metrics. The analyses were based on a real rural grid from the European FP7 project Smart Rural Grid. The performance of the EMS has been evaluated through some scenarios varying the penetration of distributed generation. The obtained results demonstrate that the inclusion of the EMS from both a technical point of view and an economic perspective for the adopted grid is justified. At the technical level, the inclusion of the EMS permits us to significantly increase the power quality in weak and radial networks. At the economic level and from a certain threshold value in renewables’ penetration, the EMS reduces the energy costs for the grid participants, minimizing imports from the external grid and compensating the toll to be paid in the form of the losses incurred by including additional equipment in the network (i.e., distributed storage).Postprint (published version