Tecnología Ultra-Wideband (UWB) : la revolución a corto alcance

Peer Reviewe

On the Measurement of Privacy as an Attacker's Estimation Error

A wide variety of privacy metrics have been proposed in the literature to evaluate the level of protection offered by privacy enhancing-technologies. Most of these metrics are specific to concrete systems and adversarial models, and are difficult to generalize or translate to other contexts. Furthermore, a better understanding of the relationships between the different privacy metrics is needed to enable more grounded and systematic approach to measuring privacy, as well as to assist systems designers in selecting the most appropriate metric for a given application. In this work we propose a theoretical framework for privacy-preserving systems, endowed with a general definition of privacy in terms of the estimation error incurred by an attacker who aims to disclose the private information that the system is designed to conceal. We show that our framework permits interpreting and comparing a number of well-known metrics under a common perspective. The arguments behind these interpretations are based on fundamental results related to the theories of information, probability and Bayes decision.Comment: This paper has 18 pages and 17 figure

Development of a Low-Cost Weather Station to Measure in Situ Essential Climate Variables

A weather station is proposed especially designed for developing countries, and to meet the standards of the international scientific community making research on the earth system. The station would measure in situ several ECV (essential climate variables). These data may enable an agricultural breakthrough in countries lacking meteorological infrastructure, help in climate change monitoring, and facilitate diffusion of wind energy. A pre-feasibility analysis is presented. It appears interesting that the station is supplied by a social enterprise. A research to establish the best shelter design using computational fluid dynamics is also reported. The criterion is the accuracy with which the surface air temperature is reproduced inside the shelter. A design following recommendations by the WMO (World Meteorological Organization), a smaller design with identical geometry, and two alternative small designs are analyzed. All four designs are simulated in PVC, natural rubber and wood, with and without white paint coating. The smaller shelters perform better. The influence of the material, dimensions and design is smaller than that of the white paint. Shelters made of PVC or rubber, and/or in alternative designs, may be more interesting if other criteria are considered, like whether logistics, manufacturing, etc. are more sustainable, easier and/or cheaper.Peer ReviewedPostprint (published version

Tesis doctoral: Estudio de la estructura y propiedades anisotropas de la litosfera subcortical del macizo Ibérico a partir de datos sísmicos de ondas p y s

A first insight to the structure of the lithosphere beneath Iberia has been provided by a P-wave travel time residual study, carried in the center of the peninsula. Both teleseismic and regional events have been studied, showing significant variations in the relative travel time residual~b etween the stations of the array. This fact has heen interpreted as an evidence of the presence of crustal heterogeneities beneath Central Iberia at short wavelength intervals. Data from the Iberian LIthospheric Heterogeneity and Anisotropy (ILIHA) deep seismic sounding experiment have been used to study the seismic structure of the lower lithosphere beneath the Ossa-Morena zone (SW Iberia). The interpretation of the mantle phases observed in the record sections evidences a layered lower lithosphere, witb alternating high and low velocity zones. Two to three main reflectors are observed in the uppermost mantle, between 30 and 90km depth. One reversed line and two intersecting unreversed lines define an area beneath SW Iberia wbere the same lithospheric reflectors segments are sampled along different azimuths. The independent analysis of the lines has shown evidences of azimuthal P-velocity anisotropy. We have inferred a model with at least two anisotropic zones in the lower lithosphere, with a roughly NNEISSW fast velocity direction A passive seismic experiment has been carried over the same SW area of Iberia to investigate the presence of anisotropy using independent  techniques and data sets. We have used a classical cross-correlation method to interpret the splitting of shear waves as the result of their propagation through anisotropic structures. Main parameters which define the characteristics of the anisotropy pattern, such as fast velocity direction and degree of anisotropy, are recovered for each event studied. The analysis of SKS and S phases shows evidence of the presence of anisotropy. The results from the different events depict a rather consistent anisotropic structure, with a rough NEISW to EN fast velocity direction. The different hypothesis suggested to explain the origin of the continental mantle anisotropy are discussed and related to tbe anisotropic pattern derived from the two data sets (DSS crossing profiies and shear wave splitting)

Human Intestinal Organoids: Promise and Challenge

The study of human intestinal biology in healthy and diseased conditions has always been challenging. Primary obstacles have included limited tissue accessibility, inadequate in vitro maintenance and ethical constrains. The development of three-dimensional organoid cultures has transformed this entirely. Intestinal organoids are self-organized three-dimensional structures that partially recapitulate the identity, cell heterogeneity and cell behaviour of the original tissue in vitro. This includes the capacity of stem cells to self-renew, as well as to differentiate towards major intestinal lineages. Therefore, over the past decade, the use of human organoid cultures has been instrumental to model human intestinal development, homeostasis, disease, and regeneration. Intestinal organoids can be derived from pluripotent stem cells (PSC) or from adult somatic intestinal stem cells (ISC). Both types of organoid sources harbour their respective strengths and weaknesses. In this mini review, we describe the applications of human intestinal organoids, discussing the differences, advantages, and disadvantages of PSC-derived and ISC-derived organoids

Geoshow3D, una aplicación de cartografía dinámica 3D

Peer Reviewe

Determination of isotopic ratios of uranium (U-235/-U238) for the characterization of reverse osmosis compared with conventional tap water treatment in order to determine the source of a water leak

An analytical technique for the determination of the isotopic ratio of U-235/U-238 in waters by a classical technique based on a quadrupole ICP-MS has been implemented.A high precision (RSD ≤ 0.3 %) has been obtained, whichis strictly necessary in these circumstances. The methodologydeveloped was validated and the results obtained confirmed a slight increase in the uranium isotopic ratio U-235/U-238 for the treated water using reverse osmosis with respect to conventionally treated water. This analytical methodology was applied to characterize different origins of treated water in the Barcelona Area in order to determine the origin of an important water leak. To the best of our knowledge, it is the first time that this isotopic application is used by a tap water distribution company to solve this kind of problem

Electrodynamic friction of a charged particle passing a conducting plate

The classical electromagnetic friction of a charged particle moving with prescribed constant velocity parallel to a planar imperfectly conducting surface is reinvestigated. As a concrete example, the Drude model is used to describe the conductor. The transverse electric and transverse magnetic contributions have very different character both in the low velocity (nonrelativistic) and high velocity (ultrarelativistic) regimes. Both numerical and analytical results are given. Most remarkably, the transverse magnetic contribution to the friction has a maximum for $|\mathbf{v}|<c$, and persists in the limit of vanishing resistivity for sufficiently high velocities. We also show how Vavilov-\v{C}erenkov radiation can be treated in the same formalism.Comment: 13 pages, 7 figures. This is the extensively revised version accepted by Physical Review Researc