Molecular Antennas and Photoactive Nanomaterials based on Energy Transfer Processes

110 p.

El desarrollo profesional de los trabajadores como ventaja competitiva de las empresas

[ES] En este trabajo se hace una revisión de la literatura sobre el concepto de profesión y a continuación se propone un modelo de desarrollo profesional en el que se destacan los retos profesionales de los trabajadores y la posibilidad de las empresas de ayudarles a afrontarlos. También se analizan los sistemas de desarrollo profesional y los roles que en ellos juegan empleados, directores y empresas. Para finalizar, se exponen varias cuestiones de actualidad relativas al desarrollo profesional: incorporación y orientación, estabilización, obsolescencia de las habilidades, doble trayectoria profesional, conflictos trabajo-familia, pérdida del puesto de trabajo y jubilación.

Influence of Training Set Selection in Artificial Neural Network-Based Propagation Path Loss Predictions

This paper analyzes the use of artificial neural networks (ANNs) for predicting the received power/path loss in both outdoor and indoor links. The approach followed has been a combined use of ANNs and ray-tracing, the latter allowing the identification and parameterization of the so-called dominant path. A complete description of the process for creating and training an ANN-based model is presented with special emphasis on the training process. More specifically, we will be discussing various techniques to arrive at valid predictions focusing on an optimum selection of the training set. A quantitative analysis based on results from two narrowband measurement campaigns, one outdoors and the other indoors, is also presented.

Empirical Doppler Characterization of Signals Scattered by Wind Turbines in the UHF Band under Near Field Condition

Time variability of the scattering signals from wind turbines may lead to degradation problems on the communication systems provided in the UHF band, especially under near field condition. In order to analyze the variability due to the rotation of the blades, this paper characterizes empirical Doppler spectra obtained from real samples of signals scattered by wind turbines with rotating blades under near field condition. A new Doppler spectrum model is proposed to fit the spectral characteristics of these signals, providing notable goodness of fit. Finally, the effect of this kind of time variability on the degradation of OFDM signals is studied.

Métodos de desacoplo de antenas PIFA en terminales móviles

[ES]Hoy en día, los sistemas de comunicación inalámbricos soportan un amplio número de servicios como la voz, datos y vídeos que requieren unas grandes tasas de transmisión. Por ello la mejora de la calidad del enlace que ofrecen los sistemas MIMO es clave. El problema surge al colocar varias antenas en un terminal móvil sin que aparezca un acoplamiento entre las distintas antenas que evite el correcto funcionamiento de estas. En este documento se realizará un estudio de los diferentes métodos de desacoplo entre antenas PIFA (Planar Inverted-F antenna) en un terminal móvil.

SIW teknologiadun antena simulazioa

[EU]Lan honetan, lehenik eta behin, SIW teknologiaren funtzionamendua ikasi dugu. Ondoren, eta gaur egun ezagunagoak diren antzeko mikrouhinetako teknologiei (microstrip, uhin gida edo antzerako transmisio lerroak) buruzko jakintza handitu ostean, hauen eta SIW teknologiaren arteko baliokidetasuna nola lortu ikasi dugu. HFSS simulazio-tresnarekin SIW teknologiadun antena ezberdinak diseinatu eta simulatu ditugu (propietate nahiz tamaina ezberdinekoak) eta hauen emaitzak aztertu, besteak beste bere erradiazio diagrama eta S parametroak. Azkenik emaitza hauek interpretatu, eta ondorio bat lortu dugu. SIW teknologiak besteekiko dituen abantailaz gain, diseinu hauek aurrera eramateko bete ditugun pausuak eta simulazio emaitzetatik lortutako interpretazioak ondorengo memoria honetan azalduko ditugu, baita lan honek izan dituen fase ezberdinak eta lan hau aurrera ateratzearen aurrekontua ere.

Effects of Spring Temperatures on the Strength of Selection on Timing of Reproduction in a Long-Distance Migratory Bird

Climate change has differentially affected the timing of seasonal events for interacting trophic levels, and this has often led to increased selection on seasonal timing. Yet, the environmental variables driving this selection have rarely been identified, limiting our ability to predict future ecological impacts of climate change. Using a dataset spanning 31 years from a natural population of pied flycatchers (Ficedula hypoleuca), we show that directional selection on timing of reproduction intensified in the first two decades (1980-2000) but weakened during the last decade (2001-2010). Against expectation, this pattern could not be explained by the temporal variation in the phenological mismatch with food abundance. We therefore explored an alternative hypothesis that selection on timing was affected by conditions individuals experience when arriving in spring at the breeding grounds: arriving early in cold conditions may reduce survival. First, we show that in female recruits, spring arrival date in the first breeding year correlates positively with hatch date; hence, early-hatched individuals experience colder conditions at arrival than late-hatched individuals. Second, we show that when temperatures at arrival in the recruitment year were high, early-hatched young had a higher recruitment probability than when temperatures were low. We interpret this as a potential cost of arriving early in colder years, and climate warming may have reduced this cost. We thus show that higher temperatures in the arrival year of recruits were associated with stronger selection for early reproduction in the years these birds were born. As arrival temperatures in the beginning of the study increased, but recently declined again, directional selection on timing of reproduction showed a nonlinear change. We demonstrate that environmental conditions with a lag of up to two years can alter selection on phenological traits in natural populations, something that has important implications for our understanding of how climate can alter patterns of selection in natural populations.