<p>An investigation was initiated, targeting snapshot 3D image sensors, with the objective to match the speed and resolution of a scanning sheet-of-light system, without using a scanning motion. The goal was a system capable of acquiring 25 snapshot images per second from a quadratic scene with a side from 50 mm to 1000 mm, sampled in 512×512 height measurement points, and with a depth resolution of 1 µm and beyond. </p><p>A wide search of information about existing 3D measurement techniques resulted in a list of possible schemes, each presented with its advantages and disadvantages. No single scheme proved successful in meeting all the requirements. Pulse modulated time-of-flight is the only scheme capable of depth imaging by using only one exposure. However, a resolution of 1 µm corresponds to a pulse edge detection accuracy of 6.67 fs when visible light or other electromagnetic waves are used. Sequentially coded light projections require a logarithmic number of exposures. By projecting several patterns at the same time, using for instance light of different colours, the required number of exposures is reduced even further. The patterns are, however, not as well focused as a laser sheet-of-light can be. </p><p>Using powerful architectural concepts such as matrix array picture processing (MAPP) and near-sensor image processing (NSIP) a sensor proposal was presented, designed to give as much support as possible to a large number of 3D imaging schemes. It allows for delayed decisions about details in the future implementation. </p><p>It is necessary to relax at leastone of the demands for this project in order to realise a working 3D imaging scheme using concurrent technology. One of the candidates for relaxation is the most obvious demand of snapshot behaviour. Furthermore, there are a number of decisions to make before designing an actual system using the recommendations presented in this thesis. The ongoing development of electronics, optics, and imaging schemes might be able to meet the 3D snapshot demands in a near future. The details of light sensing electronics must be carefully evaluated and the optical components such as lenses, projectors, and fibres should be studied in detail.</p>

We have devised a processor for pulsed Doppler radars for multi-target detection in same folded range under land and moving clutter. To this end, we have investigated the estimation of parameters, i.e., frequencies, amplitudes, and phases, of complex exponentials that model target echoes under radar clutter characterized by antenna scanning modulation with observation limited to single snapshot, i.e., one burst. The Maximum Likelihood method of estimation is presented together with the bounds on estimates, i.e., Cram&eacute / r-Rao bounds. We have analyzed linear prediction, together with its efficient implementation invented by Tufts &amp / Kumaresan, and compared its performance to other high resolution frequency estimation algorithms all modified to run under clutter. The essential part of the work is that line spectra estimation techniques model the clutter process also as a complex exponential. In addition, linear prediction combined with linear time&ndash / invariant maximum Signal to Interference Ratio (SIR) processor is analyzed. A technique to determine the model order, which is required by the frequency estimation algorithms, is presented that does not distinguish between targets and clutter. Clutter region concept is introduced to identify targets from clutter. The possibility to use these algorithms for target classification is briefly explained after providing a literature survey on helicopter echoes.

An investigation was initiated, targeting snapshot 3D image sensors, with the objective to match the speed and resolution of a scanning sheet-of-light system, without using a scanning motion. The goal was a system capable of acquiring 25 snapshot images per second from a quadratic scene with a side from 50 mm to 1000 mm, sampled in 512×512 height measurement points, and with a depth resolution of 1 µm and beyond. A wide search of information about existing 3D measurement techniques resulted in a list of possible schemes, each presented with its advantages and disadvantages. No single scheme proved successful in meeting all the requirements. Pulse modulated time-of-flight is the only scheme capable of depth imaging by using only one exposure. However, a resolution of 1 µm corresponds to a pulse edge detection accuracy of 6.67 fs when visible light or other electromagnetic waves are used. Sequentially coded light projections require a logarithmic number of exposures. By projecting several patterns at the same time, using for instance light of different colours, the required number of exposures is reduced even further. The patterns are, however, not as well focused as a laser sheet-of-light can be. Using powerful architectural concepts such as matrix array picture processing (MAPP) and near-sensor image processing (NSIP) a sensor proposal was presented, designed to give as much support as possible to a large number of 3D imaging schemes. It allows for delayed decisions about details in the future implementation. It is necessary to relax at leastone of the demands for this project in order to realise a working 3D imaging scheme using concurrent technology. One of the candidates for relaxation is the most obvious demand of snapshot behaviour. Furthermore, there are a number of decisions to make before designing an actual system using the recommendations presented in this thesis. The ongoing development of electronics, optics, and imaging schemes might be able to meet the 3D snapshot demands in a near future. The details of light sensing electronics must be carefully evaluated and the optical components such as lenses, projectors, and fibres should be studied in detail.

Esta pesquisa intitulada Verdade ou mentira? Considerações sobre o flagrante, o pseudoflagrante e a composição na fotografia de German Lorca, tem como assunto a fotografia de rua que o fotógrafo paulistano German Lorca realizou entre o final da década de 1940 e início dos anos 1950, no âmbito do Foto-Cine Clube Bandeirante. O estudo demonstra a maneira como Lorca utiliza-se do flagrante e de seu falseamento (denominado livremente de pseudoflagrante na dissertação), muitas vezes enfatizando a composição da fotografia por meio do corte. A fim de atingir esse objetivo a dissertação fundamenta-se em questões que remontam à tradição da busca da representação do movimento na arte ocidental, passando pela fotografia de rua que vem sendo praticada desde meados do século XIX, no exterior e no Brasil. Assim, mostra como noções implícitas nesse amplo contexto teriam servido de parâmetros para a produção das cenas cotidianas de German Lorca, dentro da fotografia moderna brasileira. / This research is called Verdade ou Mentira? Considerações sobre o flagrante, o pseudoflagrante e a composição na fotografia de German Lorca (True or False? Considerations on The Snapshot, The Pseudosnapshot and The Composition in German Lorcas Photography). The research has as it subject the street photographs taken by Lorca a Sao Paulo photographer , from the late 1940s to the early 1950s, within the scope of the Foto-Cine Clube Bandeirante (Bandeirante Photo-Cine Club). The study shows how Lorca uses the snapshot and its forgery (loosely called pseudosnaphot in this dissertation), often emphasizing the photographs composition by means of the cut. To meet this objective, the dissertation is based on issues that go back to western arts traditional search to represent movement, through street photographs that have been taken since the mid-nineteenth century, both in Brazil and abroad. In this way, it shows how implicit notions in this broad context would have served as parameters for German Lorcas production of everyday scenes, within modern Brazilian photography.

The possibility to use the snapshot functionality of OpenStack as a method of securing evidence has been examined in this paper. In addition, the possibility of extracting evidence automatically using an existing operation tool has been investigated. The usability of snapshots in a forensic investigation was examined by conducting a series of tests on both snapshots and physical disk images. The results of the tests were then compared to evaluate the usefulness of the snapshot. Automatic extraction of evidence was investigated by implementing a solution using Ansible and evaluating the algorithm based on the existing standard ISO 27037. It was concluded that the snapshots created by OpenStack behaves similar enough to disks to be useful in a forensic investigation. The algorithm proposed to extract evidence automatically seems to not breach the standard. / Möjligheten att använda OpenStacks ögonblicks funktion som metod för att säkra bevis har granskats i detta papper. Dessutom har möjligheten att extrahera bevis automatiskt med ett befintligt automatiseringsverktyg undersökts. Användbarheten av ögonblicksbilder i en rättslig utredning undersöktes genom att genomföra en serie tester påbåde ögonblicksbilder och fysiska disk avbilder. Resultaten av testerna jämfördes sedan för att utvärdera användbarheten av ögonblicksbilden. Automatisk utvinning av bevis undersöktes genom att implementera en lösning med Ansible och utvärdera algoritmen baserat påden befintliga standarden ISO 27037. Det drogs slutsatsen att de ögonblicksbilder som skapats av OpenStack beter sig tillräckligt lika en fysisk disk för att avbilderna ska vara användbara vid en råttslig utredning. Den algoritm som föreslås att extrahera bevis automatiskt tycks inte bryta mot standarden.

En tant qu'utilisateurs d'ordinateurs, nous générons des données en quantité de plus en plus abondante. Leur importance dans notre vie quotidienne est telle qu'une méthode de sauvegarde s'avère nécessaire. La création de sauvegardes locales est une approche commune, mais insuffisante en cas de vol ou de destruction. Dans cette thèse, nous concevons un système de sauvegarde distribué qui permet de restaurer l'état d'un système de fichiers de manière simple, grâce à la constitution d'instantanés. Nous stockons ces instantanés sur les passerelles résidentielles et utilisons un tracker centralisé pour les coordonner. Nous présentons le concept de fichiers d'indexes qui permet la correspondance entre l'état complet d'un système de fichiers et une structure de donnée. Nous divisons notre système en swarms, rendant l'accès aux données, et son suivi, simple. Les fichiers à sauvegarder sont traités différemment suivant leurs tailles, afin d'améliorer la performance globale du système, et de réduire les ressources nécessaires. Tous les fichiers, ainsi que leurs méta-données, sont chiffrés avant d'être téléchargés afin de garantir leur confidentialité. De plus, nous utilisons les techniques de l'état de l'art afin de rendre le tracker résistant aux pannes, et de pouvoir le remplacer s'il quitte le système. La charge sur le tracker ne dépend que du nombre de participants, et donc pas de la quantité de données stockée. Nous évaluons le système sur base de traces provenant de passerelles résidentielles réelles, avec lesquelles nous démontrons un faible impact global sur les ressources. En leur adjoignant des simulations, nous prouvons la faisabilité de notre service. / As computer users, we create increasing amounts of data, such as digital documents, pictures, and videos. Because these data have high value in our daily life the need for back-ups arises. The creation of local back-ups, e.g. on external hard drives, is a common approach, but is insufficient in the event of natural disasters or theft. In this thesis, we provide a proof of concept for a distributed back-up system that induces only low overhead, and respects user needs to easily recover a state of a file system in a snapshot-based manner. We store distributed back-ups on residential gateways and use a central tracker as coordinator. We introduce index files in order to map the full state of a file system to a single data structure. We divide the system into swarms of flexible size so that accessing data and monitoring is easy. Files are handled differently depending of their size in order to increase the system performance and reduce resource requirements. All files and their metadata are encrypted before being uploaded, so that data confidentiality is ensured. We use state-of-the-art technologies in order to design a tracker that is scalable, fault-tolerant, and is replaceable in case it entirely leaves the system. The load of the tracker only depends on the number of participants, not on the amount of data stored in the network. The system allows configuring a time span within which a user needs to recover his data in case of local data loss. We analyze this approach by using real world connectivity traces of residential gateways and show that it results in low resource demands. Together with simulations on these traces, we underline the feasibility of our service.

Nous proposons tout d'abord une étude de plusieurs problèmes de l'algorithmique distribuée. Nous fournissons un modèle formel appliqué aux réseaux de diffusion anonymes. Dans ce modèle, nous caractérisons les graphes dans lesquels il est possible de résoudre l'énumération et l'élection. Cette caractérisation se base sur la notion d'homomorphisme de graphes. Nous proposons deux algorithmes dont la complexité est polynomiale et qui améliorent les complexités exponentielles connues jusqu'à présent. Dans un second temps, nous étudions le problème du calcul de l'état global et nous introduisons la notion de weak snapshot. Nous montrons qu'il existe des solutions pour ce problème dans les réseaux anonymes. Nous présentons plusieurs résultats concernant le calcul de l'état global en liaison avec des applications telles que le calcul de points de reprise, la détection de la terminaison ou encore le calcul d'une cartographie du réseau. Dans un cadre plus pratique, nous présentons la conception, le développement et l'implémentation des algorithmes proposés pour le calcul de l'état global au sein du logiciel de simulation et de visualisation ViSiDiA. / In this thesis, we first present a study of several problems in the field of distributed algorithms. We provide a formal model that relies on anonymous networks. In this model, we characterize graphs in which it is possible to solve enumeration and leader election problems. This characterization is based on graph homomorphism. We introduce two algorithms with polynomial complexities that improve existing works with exponential complexities. On the other hand, we study the snapshot problem and we introduce the notion of weak snapshot. We show that there exist solutions for this problem in the context of anonymous networks. We present several results about distributed snapshots that deal with checkpoint and rollback recovery, termination detection or the cartography computation of a network. In a practical aspect, we present the conception, the development process and the implementation of these distributed snapshot algorithms within the simulation and visualization software ViSiDiA.

Being able to perform good data analysis is a fundamental part of running any business or organization. One way of enabling data analysis is with a data warehouse system, a type of database that gathers and transforms data from multiple sources and structures it in the goal of simplifying analysis. It is commonly used to provide support in decision-making. Although a data warehouse enables data analysis, it is also relevant to consider how well the system supports analysis. This thesis is a qualitative research that aims to investigate how work domain analysis (WDA) can be used to evaluate the design of a data warehouse system. To do so, a case study at the IT company Norconsult Astando was performed. A data warehouse system was designed for an issue management system and evaluated using the abstraction hierarchy (AH) model. The research done in this thesis showed that analysis was enabled by adopting Kimball’s bottom-up approach and a star schema design with an accumulating snapshot fact table. Through evaluation of the design, it was shown that most of the design choices made for the data warehouse were captured in the AH. It was concluded that with sufficient data collection methods, WDA can be used to a large extent when evaluating a data warehouse system.

Les réseaux de capteurs sans fils et mobiles constituent un champ de recherche dans lequel un grand nombre de capteurs de faible coût sont déployés dans un environnement pour observer un ou plusieurs phénomènes. Ces capteurs sont autonomes, communicant et disposent d'une réserve d'énergie limitée. Les problèmes issus de ce type de système sont nombreux : gestion de l'énergie, couverture, fusion de donnée, ...L'approche proposée dans cette thèse repose sur l'hypothèse que les réseaux de capteurs doivent exhiber des propriétés d'auto-organisation et d'autonomie. Chaque capteur est en soit autonome et peut interagir avec d'autres capteurs ce qui forme une organisation complexe. Ces capteurs ont un but à accomplir et le système possède les caractéristiques suivantes : i. le but du réseau ne peut généralement pas être résolu par un capteur uniqueii. Les capteurs doivent collaborer pour accomplir le but ou contribuer à une partie de ce but.iii. Chaque capteur réagit à son environnement en fonction de ses perceptions qui sont forcément locales et limitées.Après une introduction qui décrit le domaine et pose la problématique un état de l'art du domaine est présenté au chapitre 2. Deux contributions sont abordées dans cette thèse. D'une part, l'analyse des propriétés dynamiques de topologie des réseaux de capteurs sans fil et d'autre part la performance des liens de ce type de réseaux. Pour la topologie deux approches sont proposées : au chapitre 3 une première approche basée sur le modèle de mobilité et au chapitre 4 une approche basée sur des techniques de mesures. Pour la performance des liens, deux approches sont également proposées. La première, décrite dans le chapitre 5, est basée sur un modèle d'analyse linéaire. La deuxième, décrite au chapitre 6, repose sur une technique d'optimisation multi-objectif. / The measurability of Mobile ad hoc network (MANET) is the precondition of itsmanagement, performance optimization and network resources re-allocations. However, MANET is an infrastructure-free, multi-hop, andself-organized temporary network, comprised of a group of mobile nodes with wirelesscommunication devices. Not only does its topology structure vary with time going by, butalso the communication protocol used in its network layer or data link layer is diverse andnon-standard.In order to solve the problem of interior links performance (such as packet loss rate anddelay) measurement in MANET, this thesis has adopted an external measurement basedon network tomography (NT). To the best of our knowledge, NT technique is adaptable for Ad Hoc networkmeasurement.This thesis has deeply studied MANET measurement technique based on NT. The maincontributions are:(1) An analysis technique on MANET topology dynamic characteristic based onmobility model was proposed. At first, an Ad Hoc network mobility model formalizationis described. Then a MANET topology snapshots capturing method was proposed to findand verify that MANET topology varies in steady and non-steady state in turnperiodically. At the same time, it was proved that it was practicable in theory to introduceNT technique into Ad Hoc network measurement. The fitness hypothesis verification wasadopted to obtain the rule of Ad Hoc network topology dynamic characteristic parameters,and the Markov stochastic process was adopted to analyze MANET topology dynamiccharacteristic. The simulation results show that the method above not only is valid andgenerable to be used for all mobility models in NS-2 Tool, but also could obtain thetopology state keeping experimental formula and topology state varying probabilityformula.IV(2) An analysis technique for MANET topology dynamic characteristic based onmeasurement sample was proposed. When the scenario file of mobile models could notbe obtained beforehand, End-to-End measurement was used in MANET to obtain thepath delay time. Then topology steady period of MANET is inferred by judging whetherpath delay dithering is close to zero. At the same time, the MANET topology wasidentified by using hierarchical clustering method based on measurement sample of pathperformance during topology steady period in order to support the link performanceinference. The simulation result verified that the method above could not only detect themeasurement window time of MANET effectively, but also identify the MANETtopology architecture during measurement window time correctly.(3) A MANET link performance inference algorithm based on linear analysis modelwas proposed. The relation of inequality between link and path performance, such as lossrate of MANET, was deduced according to a linear model. The phenomena thatcommunication characteristic of packets, such as delay and loss rate, is more similarwhen the sub-paths has longer shared links was proved in the document. When the rankof the routing matrix is equal to that of its augmentation matrix, the linear model wasused to describe the Ad Hoc network link performance inference method. The simulationresults show that the algorithm not only is effective, but also has short computing time.(4) A Link performance inference algorithm based on multi-objectives optimizationwas proposed. When the rank of the routing matrix is not equal to that of its augmentationmatrix, the link performance inference was changed into multi-objectives optimizationand genetic algorithm is used to infer link performance. The probability distribution oflink performance in certain time t was obtained by performing more measurements andstatistically analyzing the hypo-solutions. Through the simulation, it can be safelyconcluded that the internal link performance, such as, link loss ratio and link delay, can beinferred correctly when the rank of the routing matrix is not equal to that of itsaugmentation matrix.

A dissertação (\"Em Flagrante - leitura de fotografias de rua do cotidiano da cidade de São Paulo nas duas primeiras décadas do século XX\" tem por fio condutor a história cultural ao lidar com a representação fotográfica. O objetivo da pesquisa realizada e o de apresentar dois pontos de vista diferenciados do comportamento do homem urbano na cidade de São Paulo antiga. Essas visões cunham o memento da modernidade da fotografia, gerada pelo flagrante ou instantâneo, que e um dos impulsos para o surgimento da cultura de massa estruturada no universo dos textos visuais. O enfoque central parte da leitura de dois olhares contrastantes de uma mesma cidade: a fotografia aplicada nas revistas A Vida Moderna e A Cigarra e o trabalho autoral do fotógrafo italiano Vincenzo Pastore. As interpretações imagéticas permitem uma reflexão sobre a questão da formação cultural da identidade brasileira no primeiro quarto do século XX. / The dissertation (Snapshots- street photographs of everyday So Paulo, during the first two decades of the twentieth century\", takes cultural history as a conducting wire, while dealing with photographic representation. The objective of the study is to present two distinct points of view of the urban man on the São Paulo streets of old. These images enhance the moment of modern photography, brought about by the snapshot, as being one of the drives for the emergence of visually based mass culture. The main focus arises in observing two contrasting photographic documentation of the same city: those of the photographs employed in the magazines A Vida Moderna (Modern Life) and A Cigarra (The Cricket) and those of the Italian photographic artist Vincenzo Pastore. The interpretations of the pictures allow for an analysis of the roots of Brazil\'s cultural identity in the first quarter of the twentieth century.