Thèses sur le sujet « Radar – Innovation »

Services have a dominant role in the world economy, with an increasing number of organisations adopting business models that incorporate product and service provision, in an effort to offer holistic customer experiences. Service innovation, as an avenue for growth, is becoming a major strategic focus in organisations worldwide. Service innovation research however, does not reflect the high level of interest in innovation shown by practitioners. There is a long tradition of product-related research that describes the conditions underlying service development in relation to products. However, evidence in the literature suggests that services are different from products and their features uniquely shape the innovation process. A significant research gap exists in the ways innovation projects are implemented in services. Existing studies fail to provide complete models of implementation that go beyond prescriptive step-by-step process manuals and to cover a variety of service industries that are as heterogeneous as products and services. This study attempts to fill these gaps by focussing on the implementation process in the under-studied service context of hotels, an industry that provides unique insights into the way interpersonal interactions shape implementation. Findings in this study derive from qualitative data collected from semi-structured interviews with managers and employees involved in two service innovation projects rolled out to European countries in 2011. Guided by a critical realist philosophy that perceives the world as mind-independent but accessible only through our subjective interpretations, the role of the researcher in this study was to approach innovation implementation by searching for valid explanations behind the participants’ experience. The study has found that the implementation process is an iterative process of planning, training, launch, review and routinisation, and follow-up periods. These are repeated as the implementation cascades through large organisations from the regional level to local organisational units. Secondary adoption and adaptation processes permeate implementation, whereby choices made at higher levels are evaluated at lower ones in a continuous cycle of decision-making. A variety of factors relating to the individuals involved, the firm where the innovation is implemented, the innovation concept, and the execution of the process have been linked to the realisation of the projects. Among these factors, knowledge, organisation of informal activities and the innovation-market fit have been shown to have the most significant positive influence on implementation. The events in the process have been explained by a combination of four mechanisms as diverse as sensemaking, organisational learning, organisational politics and emotional reactions to the implementation process. Thus, this research sheds new light on the theory and practice of service innovation implementation and paves the way for further research into the field.

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Public investments in the development of innovation in the country, either through the rigging of public universities, either through public announcements of the promotion, increased dramatically in recent years. To analyze the efficiency and effectiveness of the use of public resources is especially in times of austerity, essential for the development of a country. In this context, this research aims to identify the influence of public investments to promote innovation in the degree of maturity of innovative companies in the state of the RN. Another goal is to identify the regional influence from the installation site - capital or countryside, in the performance of the companies studied in the degree of innovation. The theoretical basis of the understanding of the scope of the concept of innovation and its determination for the purposes of this study. Typology, degree of innovation, evaluation methodologies and mechanisms to support innovation : Still on the theme of innovation additional concepts that help the reader to a greater understanding, such as are presented. Following is approached conceptualization of the triple helix, highlighting the concepts advocated by Etzkowitz and Leydesdorff, Salomon and Silva and Ipiranga, Freitas and Paiva, among others. With regard to methodological aspects, we propose a descriptive, exploratory and explanatory research quantitative and qualitative approach with the target audience group of companies served by INOVA PRO- NAGI design - multi-institutional action from a public resource called FINEP promotes the development of innovative companies in the State of Rio Grande do Norte - in 2013. The research should provide reflection and understanding of the influence of public investment in innovation, which by means of qualitative predictive variables associated with quantitative method to explain which variables are significant variations in the degree of maturity of enterprises studied
Os investimentos p?blicos no desenvolvimento da inova??o no pa?s, quer por meio do aparelhamento das universidades publicas, quer por meio de editais de fomento, cresceram vertiginosamente nos ?ltimos anos. Analisar a efici?ncia e efic?cia da aplica??o dos recursos p?blicos ?, sobretudo em tempos de austeridade, primordial para o desenvolvimento de um pa?s. Neste contexto, a presente pesquisa tem como objetivo identificar a influ?ncia dos investimentos p?blicos de fomento ? inova??o no grau de maturidade de inova??o de empresas instaladas no Estado do RN. Objetiva-se ainda identificar a influ?ncia regional, a partir do local de instala??o capital ou interior, no desempenho das empresas estudadas no grau de inova??o. A fundamenta??o te?rica parte da compreens?o da dimens?o do conceito sobre a inova??o e a sua defini??o para efeitos deste trabalho. Ainda sobre a tem?tica da inova??o s?o apresentadas conceitua??es adicionais que auxiliam o leitor a uma maior compreens?o, tais como: tipologia, graus de inova??o, metodologias de avalia??o e mecanismos de apoio ? inova??o. Na sequ?ncia ? abordada a conceitua??o sobre a tr?plice h?lice, ressaltando os conceitos preconizados por Etzkowitz e Leydesdorff, Salomon e Silva e Ipiranga, Freitas e Paiva, entre outros. No tocante aos aspectos metodol?gicos, prop?e-se uma pesquisa descritiva, explorat?ria e explicativa de abordagem quanti-qualitativa, tendo como p?blico-alvo o grupo de empresas atendidas pelo projeto PR?-INOVA NAGI a??o multiinstitucional que a partir de recursos de uma chamada p?blica da FINEP promove o desenvolvimento da inova??o em empresas do Estado do Rio Grande do Norte no ano de 2013. A pesquisa dever? proporcionar reflex?es e compreens?o da influ?ncia dos investimentos p?blicos em inova??o, que por meio de vari?veis qualitativas preditivas, associada ao m?todo quantitativo explicar quais vari?veis s?o significativas na varia??o do grau de maturidade em inova??o das empresas estudadas

Ces travaux portent sur la combinaison de dispositifs à diversité fréquentielle avec une architecture FMCW pour l’imagerie corporelle courte portée, dans le but de réduire la complexité et le coût liés à l’architecture et à la redondance des chaînes d’émission-réception. Une première étude a été menée pour comparer deux approches de multiplexage analogique : la cavité réverbérante à fuite et l’antenne à balayage fréquentiel. Cette comparaison a conclu que la première solution était la mieux adaptée au contexte de ces travaux. Un prototype a donc été développé et intégré dans un démonstrateur d’imagerie en champ proche en bande W, basé sur l’utilisation de chaînes d’émission-réception FMCW. Une preuve de concept est présentée, démontrant la capacité à reconstruire des images en bande W en utilisant une seule chaîne d’émission-réception, à partir d’un signal ayant des fréquences de l’ordre du MHz, grâce à un algorithme novateur permettant d’atteindre des taux de rafraîchissement d’image considéré comme temps réel
This research is part of a CIFRE thesis aimed at developing technologies to simplify and reduce costs associated with a body scanners dedicated to security applications, while improving the refresh rate of reconstructed images. The fundamental objective is to devise an affordable real-time imaging system. Research efforts are focused on leveraging analog multiplexing techniques based on frequency diversity, integrated into an FMCW architecture, to overcome temporal limitations inherent in existing approaches. To this end, a prototype of a leaky reverberation cavity has been conceptualized, subjected to laboratory testing, and subsequently integrated into an industrial measurement bench. This accomplishment represents a significant advancement in the evolution of a real-time imaging system utilizing an analog multiplexing device

A presente investigação científica discorre acerca da economia da inovação tendo como pano de fundo a moderna economia da empresa, explorando aspectos empíricos da Europa e um estudo de caso sobre a inovação nas micro e pequenas empresas de calçados dos vales do Sinos e do Paranhana. As bases deste estudo estão calcadas na teroria da inovação sob a ótica da teoria da firma. Para alcance dos objetivos foi realizada uma pesquisa bibliográfica buscando identificar o atual estágio das empresas europeias em comparação com as empresas brasileiras. Já o estudo de campo buscou identificar como se dá o processo de inovação nas micro e pequenas indústrias calçadistas dos Vales do Sinos e do Paranhana. Como instrumento de análise se utilizou a ferramenta do radar da inovação, objetivando identificar diferenças e similaridades entre a realidade europeia e a realidade das micro e pequenas empresas. A base deste estudo de campo surgiu da oportunidade de utilizar a pesquisa desenvolvida pela FAPERGS em conjunto com o SEBRAE, em que o autor autou como pesquisador. As evidências mostram que, para se destacar, em inovação seria necessário um equilíbrio entre todos os indicadores e que este seria um dos pontos fracos dos líderes em inovação do Cluster formado pelos Vales do Sinos e do Paranhana.
This scientific research discusses about the innovation economics, having as background the company’s modern economy, exploring empirical aspects of Europe and a case study about the innovation in micro and small footwear enterprises of Vale do Sinos and Vale do Paranhana. The basis of this study is grounded on the theory of innovation from the perspective of the theory of the firm. In order to reach the objectives, a bibliographical research was conducted, seeking to identify the current stage of European companies in comparison to Brazilian companies. On the other hand, the field work sought to identify how the process of innovation takes place in micro and small enterprises footwear of Vale do Sinos and Vale do Paranhana. As an analysis tool, the innovation radar was used, aiming at identifying similarities and differences between the European reality and the reality of micro and small enterprises. The basis of this field work arose from de opportunity to use the research developed by FAPERGS together with SEBRAE, in which the author acted as a researcher. The evidences show that, in order to excel in innovation, it would be necessary to have a balance between all indicators and that this would be one of the weaknesses of the leaders in innovation cluster formed by Vale do Sinos and Vale do Paranhana.

This thesis is dedicated to the study of innovative forward scatter radar (FSR) configurations and techniques. FSR is a specific kind of bistatic radar having bistatic angle equal or close to 180 ̊. The goal of this PhD project is to investigate techniques and configurations which would improve FSR performance, making it a more appealing system. This thesis proposes an initial radar overview with deep focus on forward scatter capabilities. FSR principles, radar cross section and target signature are widely discussed. Thus, numerous innovative studies done during this PhD project are presented. FSR passive mode, MIMO geometry and moving transmitter/ moving receiver configurations are here investigated for the first time. Numerous experimental campaigns have been undertaken and a big quantity of data has been collected. Comprehensive analyses on measured and simulated results are presented. Moreover, various novel techniques to estimate target motion parameters have been developed and tested on real and simulated data. Results show a good match between measured and estimated kinematic information. Finally, clutter in moving ends FSR is discussed. In fact, the innovative moving ends configuration is affected by Doppler shift and clutter Doppler spread. Thus, it is important to understand how this issue limits the system performance.

In the framework of the synthesis of monopulse array antennas for search-and-track applications, the thesis focuses on the development and the analysis of a method based on the sub-arraying technique aimed at generating an optimal sum and compromise difference patterns through an excitation matching procedure. By exploiting some properties of the solution space, the synthesis problem is reformulated as a combinatorial one to allow a considerable saving of computational resources. Thanks to a graph-based representation of the solution space, the use of an efficient path-searching algorithm to speed-up the convergence of the procedure for the synthesis of large array antennas as well as the use of the Ant Colony Optimizer (ACO) to benefit of its hill-climbing properties in dealing with the non-convexity of the sub-arraying problem are considered. Moreover, a hybrid approach is developed to individually control the level of the secondary lobes. In particular, the sub-array configuration is determined at the first step by exploiting the knowledge of the optimum difference mode coefficients and in the second step, the sub-array weights are computed by means of a quadratic programming procedure. In the numerical validation, a set of representative examples concerned with both pattern matching problems and pattern-feature optimization are reported in order to assess the effectiveness and flexibility of the proposed approach. Comparisons with previously published results are reported and discussed, as well.

In the framework of the synthesis of monopulse array antennas for search-and-track applications, the thesis focuses on the development and the analysis of a method based on the sub-arraying technique aimed at generating an optimal sum and compromise difference patterns through an excitation matching procedure. By exploiting some properties of the solution space, the synthesis problem is reformulated as a combinatorial one to allow a considerable saving of computational resources. Thanks to a graph-based representation of the solution space, the use of an efficient path-searching algorithm to speed-up the convergence of the procedure for the synthesis of large array antennas as well as the use of the Ant Colony Optimizer (ACO) to benefit of its hill-climbing properties in dealing with the non-convexity of the sub-arraying problem are considered. Moreover, a hybrid approach is developed to individually control the level of the secondary lobes. In particular, the sub-array configuration is determined at the first step by exploiting the knowledge of the optimum difference mode coefficients and in the second step, the sub-array weights are computed by means of a quadratic programming procedure. In the numerical validation, a set of representative examples concerned with both pattern matching problems and pattern-feature optimization are reported in order to assess the effectiveness and flexibility of the proposed approach. Comparisons with previously published results are reported and discussed, as well.

In 1400, Perugia had little home-grown artistic talent and relied upon foreign painters to provide its major altarpieces. A century later, this situation had been reversed with Perugino, Pintoricchio and Raphael all active in the city. By investigating commissioning patterns III Franciscan establishments in Perugia from 1390 to c.1527, this thesis identifies the circumstances leading to this change. It argues that artistic innovation in such peripheral places is often undervalued or automatically attributed to external factors. Focusing upon five Minorite establishments, the importance of local religious, familial and notarial networks on patronal decisions is newly evaluated. Geography-based models of the introduction and spread of ideas, particularly theories of centre-periphery and cultural exchange, are considered as a means of explaining Perugia's changing artistic status. The introduction analyses theories regarding the autonomy of peripheral patrons, the innovative potential of the periphery and the repetition of paradigms. It finds that existing models fail fully to acknowledge the periphery's contribution to artistic development which should be reappraised. Chapters 1 and 2 chart Perugian patrons' shifting preference from foreign to local painters and attribute this to changes in training, political stability, increased civic identity, and an aspirational humanist court. Chapters 3 and 4 assess the dominance of the Peruginesque style. They propose that Raphael's early success lay in his perfection of this aesthetic, along with female Baglioni/Oddi and Franciscan patronal support. This occurred in a temporary competitive vacuum, characteristic of places beyond the centre. In conclusion, some current theories undervalue the contribution of local patrons and fail to accommodate the innovative potential of peripheral places like Perugia. Ideas are generated in both places and influences flow between them through processes of exchange involving painters and patrons. Local patronal networks provide a matrix within which valid tastes are promoted independently of external pressures.

Snow is a very important environmental variable and a primary water resource in many areas of the world. Monitoring seasonal snowpack properties is crucial for properly managing snow-related hazards such as snow avalanches and snowmelt-floods. Microwave radars have been proposed as a means to non-destructively monitor snowpacks, but they have invariably employed external aids or a-priori assumptions to calculate key physical parameters of snow, such as total snow depth, snow density, snow water equivalent, and so on. This main contribution of this thesis is the proposal, design, implementation and experimental validation of an innovative radar architecture intended for snowpack monitoring, based on the use of two receivers. The proposed device can deliver estimates of total depth and wave speed in the snowpack, for both dry and wet snow conditions, without being supplemented by any additional hypothesis or device. The radar can also provides a rough estimation of the internal stratigraphy of the snowpack in terms of layer thickness, layer density and (in a preliminary form) layer wetness. The device was verified in the field with either dry or wet snowpacks in experimental sites. Another contribution of this thesis is the proposal of a novel radar technique for self-standing calculation of the Snow Water Equivalent that can be applied to bi-static radars. This technique, based on the multipath propagation of the radar signal into the snowpack, only requires a radar with two fixed antennas without any other device, movement of the antennas, or a-priori empirical assumptions. Finally, in order to improve the performance of the radar architectures proposed, a novel antenna realized by three-dimensional printing methods has been developed and experimentally tested. The antenna is based on a double-ridge waveguide configuration and is realized with different infill percentage dielectric material. The dielectric material presents low losses and a relatively high dielectric constant, reducing the encumbrance of the radar system.
Snow is a very important environmental variable and a primary water resource in many areas of the world. Monitoring seasonal snowpack properties is crucial for properly managing snow-related hazards such as snow avalanches and snowmelt-floods. Microwave radars have been proposed as a means to non-destructively monitor snowpacks, but they have invariably employed external aids or a-priori assumptions to calculate key physical parameters of snow, such as total snow depth, snow density, snow water equivalent, and so on. This main contribution of this thesis is the proposal, design, implementation and experimental validation of an innovative radar architecture intended for snowpack monitoring, based on the use of two receivers. The proposed device can deliver estimates of total depth and wave speed in the snowpack, for both dry and wet snow conditions, without being supplemented by any additional hypothesis or device. The radar can also provides a rough estimation of the internal stratigraphy of the snowpack in terms of layer thickness, layer density and (in a preliminary form) layer wetness. The device was verified in the field with either dry or wet snowpacks in experimental sites. Another contribution of this thesis is the proposal of a novel radar technique for self-standing calculation of the Snow Water Equivalent that can be applied to bi-static radars. This technique, based on the multipath propagation of the radar signal into the snowpack, only requires a radar with two fixed antennas without any other device, movement of the antennas, or a-priori empirical assumptions. Finally, in order to improve the performance of the radar architectures proposed, a novel antenna realized by three-dimensional printing methods has been developed and experimentally tested. The antenna is based on a double-ridge waveguide configuration and is realized with different infill percentage dielectric material. The dielectric material presents low losses and a relatively high dielectric constant, reducing the encumbrance of the radar system.

Le tecniche Multi-temporali SAR interferometriche (Mt-InSAR) rappresentano oggigiorno strumenti consolidati per mappare l’evoluzione temporale dei fenomeni di deformazione del suolo Terrestre. Queste tecniche utilizzano congiuntamente sets di interferogrammi SAR differenziali al fine di estrarre la componente legata alla deformazione e produrre così serie storiche di deformazione dei bersagli osservati dal sensore. L'affidabilità delle misure prodotte utilizzando algoritmi Mt-InSAR è strettamente legata alla capacità degli stessi algoritmi nell’isolare esclusivamente i segnali legati alla deformazione dal segnale complessivo interferometrico, e questa operazione diventa sempre più complessa all’aumentare dei livelli di rumore in ciascun interferogramma SAR coinvolto. Le tecniche Mt-InSAR canoniche sono altamente affidabili nel monitorare l'evoluzione dello spostamento dei target che risultano essere ampiamente stabili o coerenti per tutto il periodo di analisi. Diversamente, quando i bersagli sono particolarmente affetti da problemi di decorrelazione, le stime di deformazione ottenute risultano corrotte e inaffidabili. Questo pone le basi per lo sviluppo di processori Mt-InSAR avanzati che possano fornire stime accurate della deformazione del suolo anche in scenari con problemi di decorrelazione più o meno severi. In questo lavoro di tesi affronta dapprima lo studio dello stato dell’arte delle tecniche Mt-InSAR canoniche applicabili sia nel caso di piattaforme satellitare che terrestri, e dopodiché si propongono delle nuove tecniche Mt-InSAR per superare alcune delle criticità riscontrante. In particolare si studiano le tecniche convenzionali Mt-InSAR multigriglia per l'analisi dei target alla griglia di risoluzione spaziale più risoluta, evidenziandone le loro criticità in aree a media e bassa coerenza, e proprio in questo ambito è proposta una tecnica innovativa per meglio operare in ambienti decorrelati. Il metodo proposto si basa su efficienti operazioni con cui viene srotolata la fase (PhU) interferometrica eseguite alle scale spaziali native, ed in particolare, si srotolano dapprima gli interferogrammi alla scala di soluzione mediata (ML) attraverso algoritmi di PhU convenzionali (o avanzati). Successivamente, gli interferogrammi ML srotolati vengono utilizzati per facilitare le operazioni di PhU eseguite alla scala più fine (single-look). In dettaglio, gli interferogrammi multi-look srotolati vengono ricampionati alla griglia single-look e sottratti a modulo modulo-2π agli interferogrammi single-look. Gli interferogrammi epurati dai contributi a bassa frequenza vengono poi srotolati e aggiunti nuovamente agli interferogrammi multilook ricampionati alla griglia di risoluzione più fine. Per realizzare queste operazioni, a differenza dei metodi multigriglia canonici, non si utilizza alcun modello (lineare/non lineare) per recuperare le componenti di deformazione in alta frequenza. Infine, gli interferogrammi single-look srotolati sono opportunamente invertiti al fine di calcolare le serie storiche di deformazione del suolo attraverso un qualsiasi algoritmo a piccola baseline (SB) InSAR multi-temporale. I risultati sperimentali sono stati ottenuti elaborando una serie di dati SAR acquisiti dal sensore COSMO-SkyMed (banda X) sulla zona costiera di Shanghai, in Cina. La tesi prosegue analizzando le tecniche ai minimi quadrati pesate (WLS) e su come sono sfruttate nell’ambito InSAR al fine di migliorare l’operazione con cui si srotola la fase interferometrica e la generazione di serie storiche di deformazione. Proprio in questo contesto, utilizzando gli approcci WLS, si estende l'utilizzabilità dell'algoritmo Mt-InSAR Small BAseline Subset (SBAS) in aree caratterizzate da una coerenza spaziale medio-bassa. In particolare, pixel per pixel, si invertono esclusivamente le fasi interferometriche coerenti utilizzando una metrica a minimi quadrati pesati. Per cui attraverso una selezione adattiva, per ogni pixel si utilizzano ed invertono soltanto le fasi interferometriche coerenti, e tale caratterista può portare a diversi sottoinsiemi disgiunti di dati SAR, che sono poi invertiti sfruttando la Decomposizione a Valori Singolari Pesata (WSVD). Tuttavia, per taluni pixel, l’utilizzo esclusivo delle fasi interferometriche coerenti può portare in alcuni casi allo scarto di acquisizioni SAR particolarmente rumorose, il che si traduce in serie storiche di deformazione affidabili ma con campionamento temporale variabile. I risultati sperimentali sono stati condotti applicando la tecnica sviluppata ad un set di dati SAR acquisiti dai sensori COSMO-SkyMed (CSK) sulla regione Basilicata, nel sud Italia. Il lavoro di tesi continua analizzando le proprietà che ledono alla irrotazionalità delle triplette di fase di interferogrammi SAR multi-look. In particolare, si studiano le conseguenze delle incongruenze temporali di fase dei multi-look sulla generazione delle serie storiche di deformazione del suolo attraverso metodi SB Mt-InSAR. La ricerca condotta mostra come queste incongruenze di fase si possono propagare attraverso una rete temporale ridondante di interferogrammi SB, ed insieme agli errori di PhU, pregiudicano la qualità dei prodotti InSAR generati. In letteratura questo effetto va sotto il nome di bias di fase, il quale può pregiudicare l’affidabilità dei metodi SB quando si impostano delle soglie sulla massima baseline temporale troppo stringenti (nell’ordine di 30 giorni o meno). Proponiamo così, due nuovi metodi per la compensazione di tali fenomeni di bias, i quali metodi sono stati testati utilizzando dati SAR simulati e reali. I dati reali sono stati acquisiti dai sensori Sentinel-1A/B (banda C) sulle aree del Nevada (U.S.), e sulla zona del monte Etna in Sicilia, nel sud Italia. Dopo lo sviluppo di algoritmi per la parte satellitare, il lavoro si sposta sui sensori SAR terrestri (GB-SAR). In questo ambito proponiamo un metodo per stimare e compensare i disturbi introdotti dallo strato atmosferico (APS) in interferogrammi GB-SAR. Un’ambia analisi fisica, statistica e matematica dell'approccio presentato è fornita, discutendo inoltre le potenzialità e i limiti del metodo che a differenza di altri algoritmi, che stimano l'APS dai segnali di fase srotolati, nella metodologia proposta la compensazione avviene direttamente sul dato arrotolato, in modo tale che la stima non è affetta da nessun potenziale errore di PhU. Gli esperimenti eseguiti su dati InSAR GB-SAR simulati e reali confermano la validità della tecnica proposta, confermando inoltre che il metodo è vantaggioso nelle zone caratterizzate da una forte escursione di quota (come ad esempio nelle regioni Alpine e montuose). Infine, viene presentata un'applicazione SAR interferometrica per la stima delle deformazioni della superficie investigata in tre dimensioni (3-D) attraverso l'uso congiunto ed integrato di dati SAR acquisiti da piattaforme satellitari e terrestri. Più precisamente, la catena di combinazione interferometrica sviluppata si compone anche degli innovativi algoritmi Mt-InSAR sviluppati in questo lavoro di tesi, al fine di ottenere mappe di velocità media di deformazione 3-D direttamente alla griglia spaziale più risoluta possibile. Inoltre, in conclusione, vengono menzionate anche alcune interessanti applicazioni SAR satellitari in ambito di prevenzione ed analisi di particolari fenomeni naturali e indotti dall'uomo.
Multi-temporal SAR interferometric (Mt-InSAR) techniques are nowadays mature tools to measure the temporal evolution of the Earth’s surface with millimetric accuracy. The reliability of crustal measurements is closely related to the goodness of the used Mt-InSAR algorithms in isolating the deformation-related signal from the overall signal, and this becomes increasingly complex as the noise levels of each interferogram increase. Canonical techniques are highly reliable in monitoring the displacement evolution of targets that are found to be largely stable or coherent over the entire period of analysis. Otherwise, when the scatterers are particularly affected by decorrelation problems, the obtained deformation estimates turn out to be corrupted and unreliable. Thus, there is a strong demand for new advanced Mt-InSAR processors that can provide accurate estimates of crustal deformation even in scenarios with more or less severe decorrelation problems. This thesis work focuses on the study of multi-temporal InSAR techniques applicable in both satellite and terrestrial case. Specifically, the canonical Mt-InSAR multigrid techniques for analyzing targets at the finest resolution grid will be discussed extensively highlighting their criticality in medium to low coherence areas, and in this context an innovative technique is proposed to better operate in decorrelated environments. The new method relies on efficient phase-unwrapping (PhU) operations performed at the native spatial scales. In particular, a set of multi-look (ML) interferograms is first unwrapped using conventional (or advanced) PhU algorithms at the regional scale. Subsequently, ML unwrapped interferograms are used to facilitate the PhU operations performed at the local scale (single-look). Specifically, the unwrapped multi-look interferograms are resampled to the single-look grid and modulo-2π subtracted to the single-look interferograms. These phase residuals are then unwrapped and added back to the multi-look resampled interferograms. To accomplish these operations, at variance with alternative multiscale methods, no (linear/nonlinear) models are used to fit the spatial high-pass phase residuals. Finally, the unwrapped single-look interferograms are properly inverted to retrieve the ground displacement time series using any small baseline (SB)-oriented multitemporal InSAR tool. Experimental results are performed by processing a set of SAR data acquired by the X-band COSMO-SkyMed sensor over the coastal area of Shanghai, China. Then, the focusing moves on the Weighted Least-squares (WLS) techniques applied within the InSAR framework for improving the performance of the phase unwrapping operations as well as for better conveying the inversion of sequences of unwrapped interferograms to generate ground displacement maps. In both cases, the identification of low-coherent areas, where the standard deviation of the phase is high, is requested. Therefore, a WLS method that extends the usability of the Mt-InSAR Small BAseline Subset (SBAS) algorithm in regions with medium-to-low coherence is presented. In particular, the proposed method relies on the adaptive selection and exploitation, pixel-by-pixel, of the medium-to-high coherent interferograms, only, so as to discard the noisy phase measurements. The selected interferometric phase values are then inverted by solving a WLS optimization problem. Noteworthy, the adopted, pixel-dependent selection of the “good” interferograms to be inverted may lead the available SAR data to be grouped into several disjointed subsets, which are then connected, exploiting the Weighted Singular Value Decomposition (WSVD) method. However, in some critical noisy regions, it may also happen that discarding of the incoherent interferograms may lead to rejecting some SAR acquisitions from the generated ground displacement time-series, at the cost of the reduced temporal sampling of the data measurements. Thus, variable-length ground displacement time-series are generated. The presented experiments have been carried out by applying the developed technique to a SAR dataset acquired by the COSMO-SkyMed (CSK) sensors over the Basilicata region, Southern Italy. In the continuation of the thesis work, the properties characterizing the phase non-closure of multi-look SAR interferograms are explored. Precisely, we study the implications of multi-look phase time incongruences on the generation of ground displacement time-series through SB Mt-InSAR methods. Our research clarifies how these phase inconsistencies can propagate through a time-redundant network of SB interferograms and contribute, along with PhU errors, to the quality of the generated ground displacement products. Moreover, we analyze the effects of short-lived phase bias signals that could happen in sequences of short baseline interferograms and propose a strategy for their mitigation. The developed methods have been tested using both simulated and real SAR data. The latter were collected by the Sentinel-1A/B (C-band) sensors over the study areas of Nevada state, U.S., and Sicily Island, Italy. After the development of algorithms for the satellite part, the work veers to ground-based SAR (GB-SAR) sensors. In this field, we propose a method for estimating and compensating the atmospheric phase screen (APS) in sets of SAR interferograms generated with a GB-SAR instrument. We address the presented approach’s physical, statistical, and mathematical framework by discussing its potential and limitations. In contrast with other existing algorithms that estimate the APS from the unwrapped phase signals, our methodology is based on the straightforward analysis of the wrapped phases, directly. Therefore, the method is not affected by any potential phase unwrapping mistake, and it is suitable for Mt-InSAR applications. The effects of the local topography, the decorrelation noise, and the ground deformation on the APS estimates are deeply studied. Experiments performed on simulated and real GB-SAR InSAR data corroborate the validity of the theory. In particular, the simulated results show that the method is beneficial in zones with medium-to-high topographic slopes (e.g., for Alpine and mountainous regions). Further, an interferometric SAR application for the study of three-dimensional (3-D) deformation through the joint and integrated use of satellite and ground SAR data is presented. More precisely, the interferometric data-combining technique exploits the innovative Mt-InSAR algorithms mentioned above, and allows obtaining 3-D mean displacement velocity maps at the finest spatial grid among the available data. In conclusion, also some interested satellite SAR applications in prevention and analysis of particular natural and human-induced disasters are given.

In this work, the synthesis of clustered phased array antennas characterized by an irregular organization of tiles modules is addressed. By exploiting tiling theorems drawn from the mathematical theory, optimal and sub-optimal methods for the optimization of tiles arrangements and the corresponding excitations minimizing user-defined cost functions are presented. An enumerative approach able to retrieve the optimal clustering providing the maximum aperture coverage and the best radiation performance is proposed to deal with the synthesis of low/medium-size arrays. Based on the same optimal theorems and still exploiting the algorithmic procedures at the basis of the enumerative approach, an innovative schemata-bas ed optimization method is introduced for designing large arrays, as well. A set of numerical examples and full-wave simulations, concerned with different aperture sizes, is reported to assess the effectiveness, the limitations, and the ranges of computationally-admissible applicability of the proposed methods.

In this work, the synthesis of clustered phased array antennas characterized by an irregular organization of tiles modules is addressed. By exploiting tiling theorems drawn from the mathematical theory, optimal and sub-optimal methods for the optimization of tiles arrangements and the corresponding excitations minimizing user-defined cost functions are presented. An enumerative approach able to retrieve the optimal clustering providing the maximum aperture coverage and the best radiation performance is proposed to deal with the synthesis of low/medium-size arrays. Based on the same optimal theorems and still exploiting the algorithmic procedures at the basis of the enumerative approach, an innovative schemata-bas ed optimization method is introduced for designing large arrays, as well. A set of numerical examples and full-wave simulations, concerned with different aperture sizes, is reported to assess the effectiveness, the limitations, and the ranges of computationally-admissible applicability of the proposed methods.

In questo lavoro è stato affrontato il problema della corretta ricezione di segnali a 1090 MHz in ambienti ad alta densità di traffico. I segnali oggetto degli studi sono quelli utilizzati dai sistemi per la sorveglianza del traffico aereo (ATC): il radar secondario di sorveglianza (SSR), il sistema ADS-B (Automatic Dependent Surveillance-Broadcast), i sistemi di multilaterazione (MLAT e WAM), il sistema TIS-B ed il sistema T-CAS (Traffic Collisions Avoidance System). Le sorgenti dei segnali sono: i transponder avionici, i transponder veicolari e le stazioni trasmittenti del sistema TIS-B (Traffic Information System – Broadcast). I transponder trasmettono segnali di modo convenzionale e di modo S a seguito di interrogazioni da parte del radar secondario di sorveglianza, da parte di sistemi MLAT/WAM attivi e da parte dei sistemi T-CAS. I transponder di modo S inoltre trasmettono anche dei segnali spontanei detti squitter. Le stazioni TIS-B trasmettono segnali di modo S con la funzione di aggiornare gli aeromobili dotati di ADS-B sul traffico di aeromobili non dotati di ADS-B. Un ricevitore a 1090 MHz collocato in un ambiente ad alta densità di traffico possiede una probabilità non trascurabile di ricevere segnali sovrapposti nel tempo, soprattutto se dotato di antenna ricevente omnidirezionale. Inevitabilmente una tale situazione impedisce la corretta ricezione e decodifica di tutti i segnali, pregiudicando l’integrità della sorveglianza. Le tecniche proposte per affrontare il problema della ricezione di segnali sovrapposti sfruttano la diversità di antenna per rivelare la presenza di segnali sovrapposti e separarli. Tali metodi prevedono l’uso di una antenna ad array ed un ricevitore multicanale. Viene proposta anche una soluzione basata sull’uso di un ricevitore mono canale ed antenna omnidirezionale. Gli algoritmi presentati sono stati valutati tramite dei test utilizzando segnali reali registrati. Infine viene mostrato come aumenta la capacità del canale a 1090 MHz grazie all’utilizzo delle tecniche proposte.
This work addresses the reception problem of 1090 MHz signals in high traffic density environment. The 1090 MHz signals are used in air traffic control systems: The secondary surveillance radar (SSR), the ADS-B (Automatic Dependent Surveillance-Broadcast), the multilateration systems (MLAT and WAM ), the TIS-B (Traffic Information System - Broadcast) system and the T-CAS (Traffic Collisions Avoidance System). The signals sources are: the avionic transponder, the vehicular transponder and the TIS-B ground stations. The transponders transmit conventional and Mode S signals after receiving an interrogation by the secondary radar surveillance systems, by active MLAT / WAM and by T-CAS systems. Mode S transponders also transmit squitters, i.e. spontaneously emitted signals. The TIS-B ground-stations transmit Mode S signals in order to update the non-ADS-B traffic to the aircraft equipped with ADS-B (it is an ADS-B gap filler). A 1090 MHz receiver placed in a high traffic environment has a significant probability of receiving signals overlapping in time, particularly while using omnidirectional receiving antenna. Inevitably, this situation prevents the proper reception and decoding of all signals, compromising the integrity of surveillance. The thesis propose several methods to address the problem of overlapping received signal exploiting the antenna diversity, via an antenna array, for signals detection, separation, and decoding. These methods necessitate the use of an antenna array and a multichannel receiver, but also a mono-channel algorithm is proposed, which is useful for older systems that have only a single omnidirectional antenna. The presented algorithms have been assessed using real recorded signals. Finally the 1090 MHz channel capacity enhancement using the proposed methods is demonstrated.

With the advent of the first satellites for Earth Observation: Landsat-1 in July 1972 and ERS-1 in May 1991, the discipline of environmental remote sensing has become, over time, increasingly fundamental for the study of phenomena characterizing the planet Earth. The goal of environmental remote sensing is to perform detailed analyses and to monitor the temporal evolution of different physical phenomena, exploiting the mechanisms of interaction between the objects that are present in an observed scene and the electromagnetic radiation detected by sensors, placed at a distance from the scene, operating at different frequencies. The analyzed physical phenomena are those related to climate change, weather forecasts, global ocean circulation, greenhouse gas profiling, earthquakes, volcanic eruptions, soil subsidence, and the effects of rapid urbanization processes. Generally, remote sensing sensors are of two primary types: active and passive. Active sensors use their own source of electromagnetic radiation to illuminate and analyze an area of interest. An active sensor emits radiation in the direction of the area to be investigated and then detects and measures the radiation that is backscattered from the objects contained in that area. Passive sensors, on the other hand, detect natural electromagnetic radiation (e.g., from the Sun in the visible band and the Earth in the infrared and microwave bands) emitted or reflected by the object contained in the observed scene. The scientific community has dedicated many resources to developing techniques to estimate, study and analyze Earth’s geophysical parameters. These techniques differ for active and passive sensors because they depend strictly on the type of the measured physical quantity. In my P.h.D. work, inversion techniques for estimating Earth’s surface and atmosphere geophysical parameters will be addressed, emphasizing methods based on machine learning (ML). In particular, the study of cloud microphysics and the characterization of Earth’s surface changes phenomenon are the critical points of this work.

Wireless operation, near-field or far-field, is a core functionality of any mobile or autonomous system. These systems are battery operated or most often utilize energy scavenging as a means of power generation. Limited access to power, expected long and uninterrupted operation, and constrained physical parameters (e.g. weight and size), which limit overall power harvesting capabilities, are factors that outline the importance for innovative low-power approaches and designs in advanced low-power wireless applications. Low-power approaches become especially important for the wireless transceiver, the block in charge of wireless/remote functionality of the system, as this block is usually the most power hungry component in an integrated system-on-chip (SoC). Three such advanced applications with stringent power requirements are examined including space-based exploratory remote sensing probes and their associated radiation effects, millimeter-wave phased-array radar for high-altitude tactical and geological imaging, and implantable biomedical devices (IMDs), leading to the proposal and implementation of low-power wireless solutions for these applications in SiGe BiCMOS and CMOS and platforms.

This case study illustrates the application of the Value Creation Radar (VCR) to SenSyF, an Earth Observation (EO) system which was developed by Deimos Engenharia S.A. (DME), the Portuguese affiliate of Elecnor Deimos. It describes how a team of consultants adopted the VCR in order to find new market applications for SenSyF, selected the one with the highest potential, and defined a path to guarantee a sustainable market launch. This case study highlights the main challenges of bringing a technology-driven company closer to the market in the pursuit of long-term sustainability, while not compromising its technological capabilities

An innovative electromagnetic model for the radar echoes received by a microwave altimeter is proposed: it is based on fractal models employed both to describe the natural surface and to evaluate the surface scattering behaviour. The scattering surface is modelled by means of the fractional Brownian model (fBm) process, whose realizations are obtained by using the band-limited Weierstrass-Mandelbrot (WM) function. The scattering process is evaluated by means of the Physical Optics solution specifically derived for fractal surfaces. Rationale to apply this solution to the evaluation (in time domain) of the received echoes is provided. Dependence of the return pulse shapes on surface topography at different roughness scales is highlighted: some relevant meaningful examples are presented. Simulation results are provided to show the potential of the proposed technique that could be the fundamental element to generate an atlas of expected returns from a given radar altimeter.

In this Thesis several state-of-the-art and innovative techniques for Digital Elevation Model (DEM) generation from Synthetic Aperture Radar (SAR) images are deeply analyzed, with a special focus on the methods which allow the improvement of the accuracy of the DEM product, which is directly related to the geolocation accuracy of geocoded images and is considered as an enabling factor for a large series of civilian and Defence applications. Furthermore, some of the proposed techniques, which are based both on phase and amplitude information, are experimented on real data, i.e. COSMO-SkyMed (CSK) data, assessing the achievable performances compared with the state-of-the-art, and pointing out and quantitatively highlighting the acquisition and processing strategies which would allow to maximize the quality of the results. Moreover, a critical analysis is performed about the main errors affecting the applied techniques, as well as the limitations of the orbital configurations, identifying several complementary techniques which would allow to overcome or mitigate the observed drawbacks. An innovative procedure for on-demand DEM production from CSK SAR data is elaborated and proposed, as well as an auto-validation technique which would enable the validation of the produced DEM also where vertical ground truths are not available. Based on the obtained results and on the consequent critical analysis, several interferometric specifications for new generation SAR satellites are identified. Finally, a literature review is proposed about the main state-of-the-art ship monitoring techniques, considered as one of the main fields of application which takes benefit from SAR data, based on single/multi-platform multi-channel SAR data, with a focus on TanDEM-X (TDX). In particular, in Chapter 1 the main concepts concerning SAR operating principles are introduced and the main characteristics and performances of CSK and TDX satellite systems are described; in Chapter 2 a review is proposed about the state-of-the-art SAR interferometric techniques for DEM generation, analyzing all the relevant processing steps and deepening the study of the main solutions recently proposed in the literature to increase the accuracy of the interferometric processing; in Chapter 3 complementary and innovative techniques respect to the interferometric processing are analyzed to mitigate disadvantages and to improve performances; in Chapter 4 experimental results are presented, obtained in the generation of high accuracy DEM by applying to a dataset of CSK images properly selected state-of-the-art interferometric techniques and innovative methods to improve DEM accuracy, exploring relevant limitations, and pointing out innovative acquisition and processing strategies. In Chapter 5, the basic principles of Ground Moving Target Indication (GMTI) are described, focusing on Displaced Phase Center Antenna (DPCA) and Along-Track Interferometry (ATI) techniques.

The present Ph.D. Thesis investigates remote sensing bathymetric techniques in coastal area based on the use of Synthetic Aperture Radar (SAR) data. Since SAR signal is not able to pass sea surface and to reach sea bottom, indirect processes with sea floor morphology sensed through the effects it may have on sea surface are investigated. The conventional bathymetric techniques are briefly analyzed and the main advantages related to the use of remote sensing SAR-based bathymetric techniques highlighted. Proper sea surface modeling is performed and its interaction with SAR is investigated. Two different bathymetric techniques are proposed: the Wave-Based Approach (WBA) and the Current-Based Approach (CBA). Several theories for proper modeling of the involved phenomena and of their retrieval from SAR images are presented and the most promising are identified. An error budget analysis is performed and potential performance, specifications and requirements of the considered bathymetric approaches are described. With specific reference to the area of the Gulf of Naples, Italy, the Wave-Based Approach is selected because of current velocity being too slow or too irregular both in time and in intensity for proper application of the Current-Based Approach. Therefore, a WBA algorithm for sea surface spectrum retrieval from SAR data is proposed. The proposed WBA algorithm is applied on both L-band ALOS PALSAR images and X-band COSMO-SkyMed SAR images covering the area of the Gulf of Naples, Italy. The experimental results and the achieved improvements with respect to the approaches found in the available literature are presented. Digital Elevation Models (DEMs) of seabed are obtained and a correlation analysis with the retrieved water depth values from the official nautical charts provided by the Italian Navy Hydrographic Institute is performed.

Il presente lavoro riguarda lo studio e lo sviluppo di approcci innovativi all’identificazione dinamica delle strutture e del danno strutturale per le costruzioni storiche in muratura. Il patrimonio storico architettonico, prevalentemente costituito da costruzioni in muratura, rappresenta una parte fondamentale del patrimonio culturale di una nazione; la sua salvaguardia è dunque un’attività strettamente necessaria per la conservazione nel tempo dell’identità culturale dei popoli. Questa necessità si scontra spesso con la scarsa conoscenza del comportamento strutturale di questo genere di costruzioni. Le tecniche di identificazione dinamica delle strutture e del danno si inseriscono in questo contesto. Il loro utilizzo combinato, infatti, consente di ottenere informazioni sulle caratteristiche meccaniche globali e locali delle strutture, necessarie a calibrare i modelli strutturali e progettare interventi di conservazione mirati ed efficaci. Tuttavia, queste tecniche presentano ancora diverse problematiche che ne limitano l’applicazione alle costruzioni in muratura: il tradizionale set-up sperimentale per l’identificazione dinamica delle strutture è alquanto complesso e impegnativo; inoltre, gran parte delle tecniche di identificazione dinamica del danno è troppo generale e non tiene conto delle peculiari caratteristiche di queste costruzioni. In questo lavoro vengono proposte soluzioni originali ad entrambe le problematiche, attraverso la combinazione di approcci teorici originali e di tecniche sperimentali avanzate, applicate in modo innovativo. Per l’identificazione dinamica delle strutture, sono state esplorate le potenzialità e i limiti dell’interferometria radar, una tecnica innovativa per la misurazione a distanza delle vibrazioni strutturali. In particolare, considerata l’incapacità di ricostruire lo sviluppo tridimensionale e spaziale delle forme modali di una struttura con un solo interferometro, sono stati sviluppati modelli teorici e approcci sperimentali speditivi che prevedono l’utilizzo simultaneo di due interferometri. Per l’identificazione dinamica del danno, dato il ruolo portante che gli archi rivestono all’interno delle costruzioni in muratura, è stato sviluppato un approccio ad hoc che, dalla variazione delle frequenze naturali, permette di localizzare e quantificare danni multipli in questi elementi strutturali. L’approccio è stato sviluppato considerando le principali caratteristiche strutturali degli archi in muratura e dei fenomeni di danneggiamento di maggiore rilevanza per tale tipo di strutture. Tutti gli approcci proposti sono stati validati attraverso prove sperimentali in laboratorio e in situ.
This work concerns the study and development of innovative approaches to dynamic structural identification and dynamic damage identification for masonry constructions. The architectural heritage, mainly composed of masonry constructions, represents a fundamental part of the cultural heritage of countries; therefore, its preservation is an essential goal for our society and for the scientific community. Anyway, one of the most critical issue is the lack of knowledge on the structural behavior of these constructions. Dynamic testing and dynamic-based structural damage identification techniques could play a major role for overcoming this obstacle. Indeed, the combined use of these techniques makes it possible to get information about the global and the local structural features, essential for calibrating structural models and designing specific and effective conservation interventions. However, these techniques still show some drawbacks which hinder their application to masonry constructions: the traditional experimental setup for dynamic testing of structures is complex and highly demanding; moreover, most dynamic-based damage identification methods are too general and do not take into account the peculiar characteristics of masonry constructions. This thesis proposes original solutions to both problems, through the combination of original theoretical approaches and advanced experimental techniques, applied in an innovative way. As to dynamic testing, the potentials and limitations of the radar interferometry – a highly innovative technique for remotely measuring structural vibrations – were explored. In particular, because of the inability to reconstruct the three-dimensional and spatial characteristics of mode shapes of structures by using a single radar interferometer, theoretical models and expeditious experimental approaches involving the simultaneous use of two radar interferometers were developed. As to dynamic-based structural damage identification techniques, due to the fundamental role played by arches in masonry constructions, an ad hoc natural frequency-based approach for the localization and quantification of multiple damages in masonry arches was proposed. This approach has been developed considering the main structural features of blocky masonry arches and the most relevant damage phenomena possible for this type of structures. All of the proposed approaches have been validated through laboratory and in situ experimental tests.

Lidar is able to provide height and cover information which can be used to estimate selected forest attributes precisely. However, for users to evaluate whether the additional cost and complication associated with using Lidar merits adoption requires that the protocol to use lidar be thoroughly described and that a basis for selection of design parameters such as number of field plots and lidar pulse density be described. In our first analysis, we examine these issues by looking at the effects of pulse density and sample size on estimation when wall-to-wall lidar is used with a regression estimator. The effects were explored using resampling simulations. We examine both the effects on precision, and on the validity of inference. Pulse density had almost no effect on precision for the range examined, from 3 to .0625 pulses / m��. The effect of sample size on estimator precision was roughly in accordance with the behavior indicated by the variance estimator, except that for small samples the variance estimator had positive bias (the variance estimates were too small), compromising the validity of inference. In future analyses we plan to provide further context for wall-to-wall lidar-assisted estimation. While there is a lot of literature on modeling, there is limited information on how lidar-assisted approaches compare to existing methods, and what variables can or cannot be acquired, or may be acquired with reduced confidence. We expand our investigation of estimation in our second analysis by examining lidar obtained in a sampling mode in combination with Landsat. In this case we make inference about the feasibility of a lidar-assisted estimation strategy by contrasting its variance estimate with variance estimates from a variety of other sampling designs and estimators. Of key interest was how the precision of a two-stage estimator with lidar strips compared with a plot-only estimator from a simple random sampling design. We found that because the long and narrow lidar strips incorporate much of the landscape variability, if the number of lidar strips was increased from 7 to 15 strips, the precision of estimators with lidar can exceed that of estimators applied to plot-only SRS data for a much larger number of plots. Increasing the number of lidar strips is considered to be highly viable since the costs of field plots can be quite expensive in Alaska, often exceeding the cost of a lidar strip. A Landsat-assisted approach used for either an SRS or a two-stage sample was also found to perform well relative to estimators for plot-only SRS data. This proved beneficial when we combined lidar and Landsat-assisted regression estimators for two-stage designs using a composite estimator. The composite estimator yielded much better results than either estimator used alone. We did not assess the effects of changing the number of lidar strips in combination with using a composite estimator, but this is an important analysis we plan to perform in a future study. In our final analysis we leverage the synergy between lidar and Landsat to improve the explanatory power of auxiliary Landsat using a multilevel modeling strategy. We also incorporate a more sophisticated approach to processing Landsat which reflects temporal trends in individual pixels values. Our approach used lidar as an intermediary step to better match the spatial resolution of Landsat and increase the proportion of area overlapped between measurement units for the different sources of data. We developed two separate approaches for two different resolutions of data (30 m and 90 m) using multiple modeling alternatives including OLS and k nearest neighbors (KNN), and found that both resolution and the modeling approach affected estimates of residual variability, although there was no combination of model types which was a clear winner for all responses. The modeling strategies generally fared better for the 90 m approaches, and future analyses will examine a broader range of resolutions. Fortunately the approaches used are fairly flexible and there is nothing prohibiting a 1000 m implementation. In the future we also plan to look at using a more sophisticated Landsat time-series approach. The current approach essentially dampened the noise in the temporal trend for a pixel, but did not make use of information in the trend such as slope or indications of disturbance ��� which may provide additional explanatory power. In a future study we will also incorporate a multilevel modeling into estimation or mapping strategies and evaluate the contribution of the multilevel modeling strategy relative to alternate approaches.
Graduation date: 2013
Access restricted to the OSU Community at author's request from June 21, 2012 - Dec. 21, 2012