UAS Identify and Monitor Unusual Small-Scale Rhythmic Features in the Bay of Cadiz (Spain)

Unusual shore-normal and barred-like rhythmic features were found in Camposoto Beach (Bay of Cadiz, SW Spain) during a monitoring program using unmanned aerial systems (UAS). They appeared in the backshore and persisted for 6 months (October 2017-March 2018). Their characteristics and possible formation mechanism were investigated analyzing: (1) UAS-derived high-resolution digital elevation models (DEMs), (2) hydrodynamic conditions, and (3) sediment samples. The results revealed that the features did not migrate spatially, that their wavelength was well predicted by the edge wave theory, and that they shared characteristics with both small-scale low-energy finger bars (e.g., geometry/appearance and amplitude) and swash cusps (e.g., wavelength, seaward circulation pattern, and finer and better sorted material in the runnels with respect to the crests). Our findings pinpoint to highly organized swash able to reach the backshore during spring tides under low-energy and accretionary conditions as well as backwash enhanced by conditions of water-saturated sediment. This study demonstrates that rhythmic features can appear under different modalities and beach locations than the ones observed up to date, and that their unusual nature may be attributed to the low spatiotemporal resolution of the traditional coastal surveying methods in comparison with novel technologies such as UAS

Coastal macrophytes contribute to the long term geomorphological stability of Cadiz Bay

Charla presentada en el 2015 Aquatic Sciences Meeting. Aquatic Sciences: Global And Regional Perspectives — North Meets South (http://sgmeet.com/aslo/granada2015)In the Eastern Gulf of Cadiz, terrestrial sediments are mainly supplied by the large Guadalquivir and smaller Guadalete rivers, both of which are subject to substantial man-made interventions. These rivers are the main sediment source to Cadiz Bay; a shallow, meso-tidal bay with high subtidal macrophyte coverage and extensive salt marshes that appears to act as an effective filter, retaining fine material and ensuring accretion rates that match sea-level rise. Field observations suggest that the relative importance of the different mechanisms by which macrophyte canopies promote accretion is related to their species-specific biometric properties and zonation. Overall, we argue that the key mechanism which enhances long-term accretion in the bay is related to the reduction of erosive forces on the sediment bed cause by the interaction of plant canopies with local hydrodynamics, particularly during high wind events. Considering the importance of coastal macrophytes for long-term accretion, we briefly discuss how different local and regional management strategies in relation to IPCC climate change predictions may influence terrestrial derived-sediment dynamics.EU FP7-SPACE-2013: FAST - GA n.607131, Junta Andalucia: P07-RNM-2516, P09-RNM-4853, PR11-RNM-7722,MECD: CTM2008-00012/MAR, Schure-Beijerinck-Popping Fund: SBP/JK/2007-32), E.U. MarinERA Project MedEX: CTM2008-04036-E/MAR) y PERSEUS (FP7-287600)Charla en formato pd

Antennas' correlation influence on the GMD-assisted MIMO channels performance

The use of multiple antennas in MIMO (multiple-input multiple-output) systems at both the transmit and receive sides produces the effect known as antennas correlation which impact the overall channel performance, throughput and bit-error rate (BER). The geometric mean decomposition (GMD) is a signal processing technique which can be used to process transmit and receive signals in MIMO channels. The GMD pre- and post-procesing in conjunction with dirty-paper precoding shows some advantages over the popular singular value decomposition (SVD) technique which provides GMD-assisted MIMO systems a superior performance particularly when the channel is affected by antennas correlation. This paper analyses the impact of antennas correlation on the performance of GMD-assisted wireless MIMO channels highlighting the advantages over SVD-assisted ones

Historic evolution of the coastline in the sourthern sector of the Cadiz Bay

Los cambios paleogeográficos que han afectado históricamente a la Bahía interna de Cádiz han estado condicionados por la variación relativa del nivel del mar, por los cambios climáticos, por la actuación puntual de eventos energéticos (tsunamis, temporales marítimos) y por la actividad humana. Los cambios climáticos han sido especialmente determinantes, ya que han controlado la frecuencia de llegada de los temporales marítimos erosivos, así como la instalación de condiciones meteorológicas que favorecen el desarrollo de sistemas dunares activos

Amplificador de Potencia de Alto Rendimiento para Transmisores EER

Se presenta un amplificador de potencia de alto rendimiento específicamente diseñado para aplicaciones EER (Envelope Elimination Restoration) en transmisores de HF. El amplificador se compone de dos subsistemas: Un amplificador clase-E de banda ancha para HF (B = 40%, POUT = 50W @ 7.5 MHz, ηOV > 90%) excitado por un driver también de banda ancha que amplifica la componente de fase de la señal y un amplificador de envolvente derivado de un amplificador clase-D de audio (o clase-S) que presenta un rendimiento total mejor que el 90% para la mayor parte de su margen de salida y un nivel de intermodulación IMD de -30 dBc (prueba de dos tonos). El amplificador completo es capaz de obtener un rendimiento total ηOV > 80% con una potencia de salida de pico PEP = 50W @ 7.5 MHz en un ancho de banda fraccional B = 40%. Antes de realimentación el amplificador presenta un valor de linealidad para una prueba de dos tonos comprendido entre -28 dBc y -35 dBc

Análisis de un Transmisor Digital de HF Basado en la Técnica de Eliminación y Recuperación de Envolvente

An HF EER (Envelope Elimination and Restoration) Digital Transmitter simulation is presented in this paper. Effects that increase the IMD (Intermodulation Distortion) levels in an EER system are described and simulated. Basically, the main effects are the limitation of the envelope bandwidth, AMAM distortion and AM-PM distortion at the power amplifier stage, and the delay between the envelope and phase branches. These effects deteriorate the EER Digital Transmitter linearity. By means of this simulation, it is shown the contribution of every effect to the global IMD. The system was tested with a DSB (Double Side Band) signal. As a result, with an envelope bandwidth of 2kHz and a delay between branches smaller than 5 μs, more than 60 dB of intermodulation product rejection was achieved. It has also been developed an algorithm which determines the delay between branches with an error smaller than 0.035o when the signal is a non-modulated tone

Banco de medidas automático para linealización de amplificadores

This work is focused on building and configuring a measurement test bench for non linear High Power Amplifiers, more precisely those ones based on the Envelope Elimination and Restoration. At first sight the test bench is composed of several arbitrary waveform generators, an oscilloscope, a vector signal generator and a spectrum analyzer all of them controlled remotely. The test bench works automatically, that is why several software control programs have been developed in order to control all this equipment. The control programs have been developed in Matlab/Octave Scripting language and at last chance in a more low level language as C. The signal processing algorithms, taking into account that the time alignment one is the most important, have been developed in Matlab/Octave Scripting too. An improvement of 10dB in the ACPR(Adjacent Channel Power Ratio) has been obtained just by applying the time alignment algorithm developed in this wor

Procedimiento de diseño de un sistema de gestión y control de flotas heterogéneas

The purpose of this study is to set up the basis needed to develop real applications designed for the control and management of heterogeneous fleets. This paper tries to present some programming patterns which will lead to the design and development of good quality applications. The premise for this purpose should be the design of scalable, platform independent, modular and user friendly programs which require very small maintenance and if possible to give the ability to nonprogrammer users the ability to extend the application beyond their original design. To achieve it, a web design with the use of content management system following a model-view-controller architectural pattern has been purposed

Preparación del μClinux para “Software Defined Radio” con BF537

The purpose of this study is to prepare the Blackfin STAMP board with a BF537 core to work as a SDR system (Software Defined Radio System) under a GNU-Linux platform. Due to all the documentation and support found in the web and the release under GPL (General Public License), the distribution used to develop SDR is μClinux. This work explains what is needed to build a SDR system in the Blackfin board, the inconveniences found in the actual μClinux distribution and all the workarounds and approaches made to start porting the software needed to the operating system. To make it work, some codes of the linux kernel, such as device drivers, had to be reviewed so they could adjust to the application demands. In short, this work explains what has been modified in the μClinux distribution and why such changes are done to make SDR possible in the Blackfin board

Evolución histórica de la línea de costa en el sector meridional de la bahía de Cádiz

Los cambios paleogeográficos que han afectado históricamente a la Bahía interna de Cádiz han estado condicionados por la variación relativa del nivel del mar, por los cambios climáticos, por la actuación puntual de eventos energéticos (tsunamis, temporales marítimos) y por la actividad humana. Los cambios climáticos han sido especialmente determinantes, ya que han controlado la frecuencia de llegada de los temporales marítimos erosivos, así como la instalación de condiciones meteorológicas que favorecen el desarrollo de sistemas dunares activos