Ramón Martínez

A 2

The increasing interest in MIMO (Multiple-Input Multiple-Output) systems has given rise to a prolific research activity in recent years. Both theoretical and practical issues have been studied. However, so far few MIMO testbeds or prototypes have been built for DVB-T or future standards. In this paper, a novel 2 × 2 MIMO testbed specifically designed for evaluating the performances of a DVB-T2 MIMO system is presented. The description of signal processing is detailed including a new scheme to estimate the MIMO channel matrix. Finally, measurement results with different polarization schemes are presented for typical scenarios, obtaining higher capacity in LoS situations using polarization diversity.

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El asma ocupacional (AO) es la enfermedad ocupacional más frecuente en los países industrializados y se estima que aproximadamente un 15% de todas las asmas del adulto pueden ser de origen ocupacional. Un diagnóstico correcto y un temprano manejo son puntos clave para el pronóstico de la enfermedad y sus consecuencias socioeconómicas. La repercusión de estas actuaciones no sólo afecta a la persona implicada, sino que en ocasiones la modificación de las condiciones de trabajo y de otros ámbitos laborales similares puede llevar a evitar otros muchos casos. Los beneficios, así, son importantes para la salud de la población trabajadora, y también para la economía de las empresas y de la sociedad en general. Valorando la trascendencia de esta enfermedad, el comité científico de la Sociedad Española de Neumología y Cirugía Torácica (SEPAR) ha encargado al Dr. Orriols Martínez la coordinación de un grupo de excelentes profesionales, pertenecientes a las áreas de Enfermedades Respiratorias de Origen Laboral (EROL) y Asma de SEPAR, para la redacción de esta normativa, que pretende proporcionar una ayuda clara y concisa en el diagnóstico y posterior manejo del paciente en el que se sospecha AO.

2 MIMO DVB-T2 System: Design, New Channel Estimation Scheme and Measurements With Polarization Diversity

The GEODA-GRUA is one conformal adaptive antenna array designed for satellite communications. Operating at 1.7 GHz with circular polarization, it is possible to track and communicate with several satellites at once being able to receive signals in full azimuth and within the range of 5° to broadside elevation thanks to its adaptive beam. The complex structure of the antenna array has 2700 radiating elements based on a set of 60 similar triangular arrays that are divided in 15 subarrays of 3 radiating elements. A control module governs each transmission/receiver (T/R) module associated to each cell in order to manage beam steering by shifting phases.

Normativa del asma ocupacional

BACKGROUND AND OBJECTIVE: We intended to perform a descriptive-evolutive study of a series of patients diagnosed with Reactive Airways Dysfunction Syndrome. PATIENTS AND METHOD: Retrospective study of 18 patients diagnosed with Reactive Airways Dysfunction Syndrome. Clinical data, functional respiratory study, and allergic and laboratory tests were collected. The clinical, functional and occupational evolution one year after diagnosis was evaluated. RESULTS: Twelve men and 4 women aged 27 to 66 years were evaluated. More frequent activities were metallurgy and cleaning, and the related agents were derived from chlorine and sulphur. Time from the beginning of exposure to development of symptoms was 1 hour in 10 (55%) patients and less than 24 hours in all cases. All patients reported to have dyspnea (100%), 12 (67%) wheezing, 8 (44%) nose and throat symptoms, 8 (44%) general symptoms such as headache and vomits, and 4 (22%) ocular manifestations. Although all patients received medical assistance after exposure, a correct diagnosis was made some months or years later (average time 3.6 years). At that time there was an airway obstruction in 6 of 18 (33%) patients. With regard to the clinical evolution, there was an improvement in 8 of 18 (44%) patients, while the rest remained stable. In the functional follow up, 8 of 17 (47%) showed no changes, 6 of 17 (35%) improved and 3 of 17 (18%) worsened. Among the patients who inhaled in the workplace, 7 of 14 (50%) continued working in the same job, 5 of 14 (36%) were off sick and 2 of 14 (14%) changed their role in the same company. CONCLUSIONS: Reactive Airways Dysfunction Syndrome is not frequently suspected and thus its diagnosis and treatment can be delayed for months or years.

GEODA-GRUA: Adaptive multibeam conformal antenna for satellites communications

A near-field highly focused circular phased-array antenna for 5.8-GHz radio frequency identification (RFID) applications is presented. The electric field (E-field) at the focus is enhanced by a constructive vector combination in a three-dimensional (3-D) coordinate system. The array dipoles of the antenna are oriented to enhance the energy confinement at the focus, and the radii of the circular array is optimized for lower sidelobe levels. As a result, the proposed design achieves an enhanced focalization of ≈ 4 dB with reduced sidelobe levels of ≈ 12 dB compared to earlier designs.

Síndrome de disfunción reactiva de las vías respiratorias. Estudio de 18 casos

The increasing interest in MIMO (Multiple-Input Multiple-Output) systems has given rise to a prolific research activity in this topic in recent years. Several aspects have been studied, including both theoretical and practical issues. However, so far few MIMO testbeds or prototypes have been done for DVB-T or future standards. In this paper, a novel 2 × 2 MIMO testbed has been realized which has been specifically designed for evaluating the performances of a DVB-T2 MIMO system.

Optimal E-Field Vector Combination for a Highly Focused Antenna-Array

In this contribution, we have presented a preliminary analysis for the implementation of the calibration algorithm to a geodesic antenna array (GEODA) and propose a new algorithm for the on-line calibration. Some simulations was presented in order to allow us explain the scope of this project and the importance of compensate the errors presented at the uncalibrated antenna.

A 2×2 novel MIMO testbed for DVB-T2 systems

Orbiting satellites and other spatial vehicles have complex trajectories that can usually be precisely approximated with analytical or numerical trajectory estimation algorithms. However, some scenarios, such as Launch and Early Orbit Phase (LEOP) or critical maneuvers, present greater angular uncertainty. During these, large dish antennas used for telemetry, tracking, & command (TT&C) may have too narrow a beamwidth to perform a reliable and fast acquisition. A novel acquisition aid system based on distributed array elements placed on the rim of the main antennas reflector has been implemented and successfully tested with real satellite signals. This paper presents an analysis of the proposed solution, from a system engineering perspective, exposes several simulations carried out in MATLAB, which motivated some of the design criteria, and compares them with the actual results obtained in field campaigns, thus deriving the final figures of merit (FoM) of the system.

Preliminary analysis of the calibration procedures for a geodesic antenna array (GEODA)

A distributed antenna array system, named Spanish acronym for fast acquisition of satellites system (SARAS), has been designed as an acquisition aid to parabolic telemetry, tracking, and command antennas when tracking satellites in launch and early orbit phase or during critical maneuvers. The system relies on digital signal processing, based on the array changing phase response to incoming signals as a function of their direction of arrival. One critical aspect for proper performance of the system is to establish a reliable model of this phase response, termed the array manifold, prior to and during satellite acquisition, through novel calibration techniques that are the focus of this letter.

Analysis of a Distributed Array System for Satellite Acquisition

The introduction of new generations of mobile communication systems, such as the current 3G and the future 4G, along with the provision of multimedia services, has exponentially increased the number of users demanding higher data rate. This fact has aroused the interest in studying possible solutions to improve system performance without making use of new frequency band allocations in the already crowded frequency spectrum. As an interesting option, wireless communication systems with Multiple-Inputs and Multiple-Outputs (MIMO) in which many antennas are used for transmission and reception have received increasing attention from the research community over the past few years (Paulraj et al., 2004, Goldsmith et al., 2003).