Orientador: Paulo Cardieri / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-26T02:54:38Z (GMT). No. of bitstreams: 1 Goes_AdrianoAlmeida_D.pdf: 4041752 bytes, checksum: 3aebfc7442e100b6011a6873be01c5f9 (MD5) Previous issue date: 2014 / Resumo: Resultados de campanhas de medição realizadas visando o desenvolvimento de uma fer-ramenta para o projeto, implantação e análise de sistemas de RFID são mostrados nesse traba-lho. Particularmente, a perda de percurso de rádio a partir de um leitor de RFID até um TAG, e de volta para o leitor é caracterizada na banda 915 MHz, para diferentes distâncias de separação leitor-TAG, alturas de TAG e de antena do leitor. Vários cenários de propagação foram considerados, incluindo ambientes exteriores e in-teriores, para os quais foi colhido um extenso número medidas. Os dados de campo são, então, comparados a uma versão melhorada do modelo clássico perda caminho 2-ray, ajustada para incluir também os padrões de radiação da antena não omnidirecionais no leitor. Além disso, foi investigado, por meio da análise de medidas de campo, o efeito da mobi-lidade do TAG no sinal recebido no leitor. Para a coleta das medidas, foi construído um aparato composto de uma esteira de velocidade controlada, onde foram instalados TAGs de teste. Os resultados de medida mostraram que a mobilidade do TAG provoca uma diminuição do valor médio e um aumento da variância do sinal recebido no leitor. Essa atenuação extra e a variância do sinal não são fortemente afetadas pelo valor da velocidade. Por fim, esses efeitos de propagação são incorporados em um modelo matemático, que pode ser utilizado para a simulação e planejamento de sistemas RFID / Abstract: Results of measurement campaigns carried out aiming at the development of a tool for design, deployment, and analysis of RFID systems are shown. Particularly, the radio path loss from an RFID reader towards the test TAG and back to the reader is characterized at the 915 MHz band. The path loss is estimated based on the received signal strength measured at the reader, for different reader¿TAG separation distances and different antenna TAG heights. Several propagation scenarios have been considered, including outdoor and indoor environments for which an extensive number of typical real manufacturing plants have been chosen. The field data are then compared to a proposed novel, improved version of the classical 2-ray path loss model, adjusted to include non-omnidirectional antenna radiation patterns at the reader. In addition, the effect of TAG mobility in the received signal at the reader was also investigated, by means of field measurements. To collect the field measurements, an apparatus was designed and constructed, consisting of a mat of controlled speed, on which test TAGs were installed. The results showed that TAG mobility decreases the average value increases the variance of the received signal at the reader. This extra attenuation and the increased variance of the signal are not strongly affected by the value of speed. Finally, these two effects are incorporated into a mathematical model that can be used for simulation and planning of RFID systems / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

In this study, the semi-empirical approach is introduced to accurately estimate the probability distribution of complex non-linear random variables in the field of wavestructure interaction. The structural form of the semi-empirical distribution is developed based on a mathematical representation of the process and the model parameters are estimated directly from utilization of the sample data. Here, three probability distributions are developed based on the quadratic transformation of the linear random variable. Assuming that the linear process follows a standard Gaussian distribution, the three-parameter Gaussian-Stokes model is derived for the second-order variables. Similarly, the three-parameter Rayleigh-Stokes model and the four-parameter Weibull- Stokes model are derived for the crests, troughs, and heights of non-linear process assuming that the linear variable has a Rayleigh distribution or a Weibull distribution. The model parameters are empirically estimated with the application of the conventional method of moments and the newer method of L-moments. Furthermore, the application of semi-empirical models in extreme analysis and estimation of extreme statistics is discussed. As a main part of this research study, the sensitivity of the model statistics to the variability of the model parameters as well as the variability in the samples is evaluated. In addition, the sample size effects on the performance of parameter estimation methods are studied. Utilizing illustrative examples, the application of semi-empirical probability distributions in the estimation of probability distribution of non-linear random variables is studied. The examples focused on the probability distribution of: wave elevations and wave crests of ocean waves and waves in the area close to an offshore structure, wave run-up over the vertical columns of an offshore structure, and ocean wave power resources. In each example, the performance of the semi-empirical model is compared with appropriate theoretical and empirical distribution models. It is observed that the semi-empirical models are successful in capturing the probability distribution of complex non-linear variables. The semi-empirical models are more flexible than the theoretical models in capturing the probability distribution of data and the models are generally more robust than the commonly used empirical models.

La stratégie la plus utilisée aujourd'hui pour la conception de nouveaux matériaux luminescents est basée sur des méthodes d'essais-erreurs. Cependant, ces méthodes peuvent souvent entraîner une consommation d'argent et de temps. En ce sens, un modèle théorique agissant comme un outil prédictif peut servir comme une stratégie alternative. De tels modèles sont également étudiés et utilisés par des scientifiques du monde entier, mais ils sont pour la plupart difficiles à utiliser. Dans ce travail, deux modèles semi-empiriques conviviaux et faciles à utiliser ont été proposés pour la conception de luminophores intégrés dans le développement de technologies importantes, en particulier dans les éclairages à base de LED et les cellules solaires. Ces modèles sont: 1) le modèle de facteur environnemental (EF) basé sur la théorie diélectrique de la liaison chimique proposée par Philips et 2) le modèle de transfert de charge métal-métal (MMCT) utilisées pour trouver des relations entre les propriétés structurelles d'un matériau et sa luminescence. Le modèle EF a été appliqué à la famille des composés AIBIIPO4 (AI = cation monovalent, BII = cation divalent) dopés à Eu2+. Il était capable d'estimer l'énergie du bord d'excitation et d'identifier les sites de dopage à ± 1000 cm-1. Il peut donc être utilisé pour la conception de nouveaux luminophores appartenant à cette famille. Dans la deuxième partie, les deux modèles ont été utilisés pour identifier la nature de la luminescence dans les oxydes dopés à Bi3+. A cet effet, une méthode combinant les modèles motionnés avec les valeurs de Stokes shift a été trouvé fiable. En outre, la a été jugée utile pour expliquer la modification des propriétés luminescentes de YVO4:Bi3+ sous haute pression. Dans la troisième partie, les deux modèles ont été utilisés pour explorer la luminescence des oxydes dopés à Sb3+ par analogie avec Bi3+. Cependant, les résultats n'étaient pas assez bons pour identifier la nature de la luminescence dans ces matériaux. La raison pourrait être liée à la position décentrée du dopant (Sb3+). / The most used strategy for the design of new luminescent materials today is based on trial-error methods. However, these methods may often result in consummation of money and time. In this sense, a theoretical model acting as a predictive tool can serve as an alternative strategy. Such models are also studied and used by scientists around the world but they are mostly difficult to use. In this work, two friendly and easy to use semi-empirical theoretical models were proposed as a criterion for designing phosphors integrated in the development of important technologies especially in LED-based lightings and solar cells. These models are: 1) the environmental factor model (EF) based on the dielectric theory of chemical bonding proposed by Philips and 2) the metal to metal charge transfer (MMCT) model by Boutinaud that were both used for the purpose of finding relationships between the structural properties of a material and its luminescence. The EF model was applied on the family of AIBIIPO4 (AI= monovalent cation, BII= divalent cation) compounds doped with Eu2+. It was able to estimate the excitation edge energy and to identify the doping sites within uncertainty of ± 1000 cm-1. It can therefore, be used for the design of new phosphors belonging to this family. In a second part, both models were used to identify the nature of luminescence in Bi3+-doped oxides. For this purpose, a method combining the mentioned models along with the values of the Stokes shift was found reliable. In addition, the method was found useful to explain the change in luminescent properties of YVO4:Bi3+ under high pressure. In the third part, the two models were used to explore the luminescence of Sb3+-doped oxides by analogy with Bi3+. However, the results were not good enough to identify the nature of luminescence in these materials. The reason could be related to the off-centered position of the dopant (Sb3+).

The major aim of this work is to develop a framework for the estimation of Evapotranspiration (ET) over the Indian landmass using remote sensing (RS) datasets in a repeated and consistent manner with improved spatial resolution. Different RS based ET models exist in the literature, out of which, the triangle, the S-SEBI and the Sim-ReSET models were compared for the estimation of daytime integrated latent heat flux (λEday). These three models were chosen as they can be driven only with RS based inputs without the need for any ground measurements. The results showed that the application of simpler contextual models may yield better results than physically based models when ground data is limited or not available. To improve the spatial resolution of one of the key surface variable, Land Surface Temperature (LST), the performance of five different vegetation indices Normalised Difference Vegetation Index (NDVI), Fraction Vegetation Cover (FVC), Normalised Difference Water Index (NDWI), Soil Adjusted Vegetation Index (SAVI) and Modified SAVI (MSAVI) were tested in the existing DisTrad disaggregation model. Results suggested that the most commonly used vegetation indices NDVI and FVC yielded better results only under wet conditions. Under drier surface conditions, using NDWI for disaggregation resulted in relatively higher accurate LST. A model for spatial disaggregation of Evaporative Fraction (EF) called DEFrac (Disaggregation of Evaporative Fraction) was developed based on the relationship between EF and NDVI to obtain finer spatial resolution EF from coarser resolution estimates. The experimental results suggested that the DEFrac model developed in this study, yielded more accurate disaggregated EF. The disaggregated EF was further used to get disaggregated λEday. Finally, The issue of lack of proper ET dataset over India was addressed by developing two data products one over entire India at 0.05° spatial resolution and the second product over the Kabini basin at 1 km spatial resolution. Both the products were developed with a temporal resolution of 8-day and for the period 2001–2014. The developed ET products were validated against ground observed data at seven sites across India and against ET simulated by a hydrological model over a forested watershed. Further the developed ET products were compared with some other global ET products such as MOD16, LandFlux Eval synthesis ET and GLEAM ET. Analyses revealed that only in regions where ET is predominantly driven by rainfall and where irrigation is not applied at very large scales, the global ET products tend to capture the ET patterns satisfactorily. On the other hand, the ET products developed in this work captured the spatial and temporal patterns of ET quite realistically all across India.