Design of radio frequency integrated circuits for ultra wide band communications

Programa de doctorado: Tecnologías de Telecomunicación Avanzadas

Comunicación robusta punto a punto con módulos embebidos de radio frecuencia XBee

Máster Universitario en Sistemas Inteligentes y Aplicaciones Numéricas en Ingeniería (SIANI)

Diseño y creación de una interfaz para el desarrollo de aplicaciones que utilicen servicios de comunicaciones por radio

[ES] La implantación en Canarias de la tecnología de radio TETRA trae como consecuencia la necesidad de una plataforma de alto nivel para operar con la red y los terminales asociados. Debido a esta necesidad se plantea el desarrollo y la implementación de una capa de acceso al hardware y la red que sea lo suficientemente escalable para así desarrollar sobre ésta un repertorio de utilidades que haga más eficiente la gestión de toda esta nueva infraestructura de comunicación. Este proyecto final de carrera se encarga de fijar las bases de esa comunicación con la red TETRA a través de sus dispositivos haciendo uso, para ello, del protocolo de comunicacion mediante comandos AT que proporciona el estándar definido por ETSI para TETRA. Como resultado del análisis y diseño del problema, se genera una librería dinámica capaz de interaccionar con los terminales y proporcionar una interfaz sencilla y común para poder generar soluciones de más alto nivel que hagan uso de la red TETRA pero sin tener en ningún momento la necesidad de conocer las peculiaridades de la capa de comunicación física de tetra. Para dar un ejemplo de las capacidades de la librería generada anteriormente, se genera a modo de ejemplo una aplicación que hace uso de la librería y que representa un prototipo de herramienta de retransmisión de mensajes entre terminales TETRA y buzones de correo, destinada a su uso en el departamento de seguridad de la ULPGC.

Submarine emissions on the seafloor : from cold seeps to hot vents

[EN] The main types of submarine geological emissions are classified as cold seeps (hydrocarbons and brines) and hot vents. These processes result in the emission of geological fluids: brine, gases (mainly hydro-carbons), sediments and rocks. Submarine emissions are associated with an intensive geological, geo-chemical, thermal and biological activity (Judd and Hovland, 2007), and constitute a key process in the dynamics of the global cycles of the planet Earth.

Multiwavelenght study of cluster mergers and consequences for the radio emission properties of galaxy clusters

In the present thesis a thourough multiwavelength analysis of a number of galaxy clusters known to be experiencing a merger event is presented. The bulk of the thesis consists in the analysis of deep radio observations of six merging clusters, which host extended radio emission on the cluster scale. A composite optical and X–ray analysis is performed in order to obtain a detailed and comprehensive picture of the cluster dynamics and possibly derive hints about the properties of the ongoing merger, such as the involved mass ratio, geometry and time scale. The combination of the high quality radio, optical and X–ray data allows us to investigate the implications of the ongoing merger for the cluster radio properties, focusing on the phenomenon of cluster scale diffuse radio sources, known as radio halos and relics. A total number of six merging clusters was selected for the present study: A3562, A697, A209, A521, RXCJ 1314.4–2515 and RXCJ 2003.5–2323. All of them were known, or suspected, to possess extended radio emission on the cluster scale, in the form of a radio halo and/or a relic. High sensitivity radio observations were carried out for all clusters using the Giant Metrewave Radio Telescope (GMRT) at low frequency (i.e. ≤ 610 MHz), in order to test the presence of a diffuse radio source and/or analyse in detail the properties of the hosted extended radio emission. For three clusters, the GMRT information was combined with higher frequency data from Very Large Array (VLA) observations. A re–analysis of the optical and X–ray data available in the public archives was carried out for all sources. Propriety deep XMM–Newton and Chandra observations were used to investigate the merger dynamics in A3562. Thanks to our multiwavelength analysis, we were able to confirm the existence of a radio halo and/or a relic in all clusters, and to connect their properties and origin to the reconstructed merging scenario for most of the investigated cases. • The existence of a small size and low power radio halo in A3562 was successfully explained in the theoretical framework of the particle re–acceleration model for the origin of radio halos, which invokes the re–acceleration of pre–existing relativistic electrons in the intracluster medium by merger–driven turbulence. • A giant radio halo was found in the massive galaxy cluster A209, which has likely undergone a past major merger and is currently experiencing a new merging process in a direction roughly orthogonal to the old merger axis. A giant radio halo was also detected in A697, whose optical and X–ray properties may be suggestive of a strong merger event along the line of sight. Given the cluster mass and the kind of merger, the existence of a giant radio halo in both clusters is expected in the framework of the re–acceleration scenario. • A radio relic was detected at the outskirts of A521, a highly dynamically disturbed cluster which is accreting a number of small mass concentrations. A possible explanation for its origin requires the presence of a merger–driven shock front at the location of the source. The spectral properties of the relic may support such interpretation and require a Mach number M < ∼ 3 for the shock. • The galaxy cluster RXCJ 1314.4–2515 is exceptional and unique in hosting two peripheral relic sources, extending on the Mpc scale, and a central small size radio halo. The existence of these sources requires the presence of an ongoing energetic merger. Our combined optical and X–ray investigation suggests that a strong merging process between two or more massive subclumps may be ongoing in this cluster. Thanks to forthcoming optical and X–ray observations, we will reconstruct in detail the merger dynamics and derive its energetics, to be related to the energy necessary for the particle re–acceleration in this cluster. • Finally, RXCJ 2003.5–2323 was found to possess a giant radio halo. This source is among the largest, most powerful and most distant (z=0.317) halos imaged so far. Unlike other radio halos, it shows a very peculiar morphology with bright clumps and filaments of emission, whose origin might be related to the relatively high redshift of the hosting cluster. Although very little optical and X–ray information is available about the cluster dynamical stage, the results of our optical analysis suggest the presence of two massive substructures which may be interacting with the cluster. Forthcoming observations in the optical and X–ray bands will allow us to confirm the expected high merging activity in this cluster. Throughout the present thesis a cosmology with H0 = 70 km s−1 Mpc−1, m=0.3 and =0.7 is assumed.

El español internacional en los medios de comunicación: estudio de un caso de un programa de radio en internet

[ES]El objetivo del presente artículo es demostrar que existe un español internacional (EI) en los medios de comunicación de Hispanoamérica. Para ello, hemos escogido un programa de radio de la norma culta del español Atlántico. Por un lado, analizamos las definiciones que se han realizado del español de los medios de comunicación-lengua especial, Lázaro Carreter, para constatar si coadyuvan a la consolidación del concepto de EI y, por otro lado, realizamos un estudio dialectal con los americanismos léxicos del corpus para verificar hasta qué punto constituyen una isoglosa que impide la inteligibilidad y, por tanto, la no existencia de un EI en los medios de comunicación.

Adaptive finite element simulation of stack pollutant emissions over complex terrains

[EN]A three-dimensional finite element model for the pollutant dispersion is presented. In these environmental processes over a complex terrain, a mesh generator capable of adapting itself to the topographic characteristics is essential. The first stage of the model consists on the construction of an adaptive tetrahedral mesh of a rectangular region bounded in its lower part by the terrain and in its upper part by a horizontal plane. Once the mesh is constructed, an adaptive local refinement of tetrahedra is used in order to capture the plume rise. Wind measurements are used to compute an interpolated wind field, that is modified by using a mass-consistent model and perturbing its vertical component to introduce the plume rise effect...

High-resolution simulation of stack pollutant emissions

[EN]A three-dimensional air pollution model for the short-term simulation of emission, transport and reaction of pollutants is presented. In the finite element simulation of these environmental processes over a complex terrain, a mesh generator capable of adapting itself to the topographic characteristics is essential, A local refinement of tetrahedra is used in order to capture the plume rise. Then a wind field is computed by using a mass-consistent model and perturbing its vertical component to introduce the plume rise effect. Finally, an Eulerian convection-diffusionreaction model is used to simulate the pollutant dispersion…

Three-dimensional finite element modelling of stack pollutant emissions

[EN]In this paper we propose a finite element method approach for modelling the air quality in a local scale over complex terrain. The area of interest is up to tens of kilometres and it includes pollutant sources. The proposed methodology involves the generation of an adaptive tetrahedral mesh, the computation of an ambient wind field, the inclusion of the plume rise effect in the wind field, and the simulation of transport and reaction of pollutants. The methodology is used to simulate a fictitious pollution episode in La Palma island (Canary Island, Spain)…

Local scale finite element modelling of stack pollutant emissions

Congresos y conferencias

Cognitive radio in HF communications: selective transmission and broadband acquisition

Mención Internacional