Real-world radiance values can range over eight orders of magnitude from starlight to direct sunlight but few digital cameras capture more than three orders in a single Low Dynamic Range (LDR) image. We approach this problem using established High Dynamic Range (HDR) techniques in which multiple images are captured with different exposure times so that all portions of the scene are correctly exposed at least once. These images are then combined to create an HDR image capturing the full range of the scene. HDR capture introduces new challenges; movement in the scene creates faded copies of moving objects, referred to as ghosts. Many techniques have been introduced to handle ghosting, but typically they either address specific types of ghosting, or are computationally very expensive. We address ghosting by first detecting moving objects, then reducing their contribution to the final composite on a frame-by-frame basis. The detection of motion is addressed by performing change detection on exposure-normalized images. Additional special cases are developed based on a priori knowledge of the changing exposures; for example, if exposure is increasing every shot, then any decrease in intensity in the LDR images is a strong indicator of motion. Recent Superpixel over-segmentation techniques are used to refine the detection. We also propose a novel solution for areas that see motion throughout the capture, such as foliage blowing in the wind. Such areas are detected as always moving, and are replaced with information from a single input image, and the replacement of corrupted regions can be tailored to the scenario. We present our approach in the context of a panoramic tele-presence system. Tele-presence systems allow a user to experience a remote environment, aiming to create a realistic sense of "being there" and such a system should therefore provide a high quality visual rendition of the environment. Furthermore, panoramas, by virtue of capturing a greater proportion of a real-world scene, are often exposed to a greater dynamic range than standard photographs. Both facets of this system therefore stand to benefit from HDR imaging techniques. We demonstrate the success of our approach on multiple challenging ghosting scenarios, and compare our results with state-of-the-art methods previously proposed. We also demonstrate computational savings over these methods.

Hauntology Man, a 48-minute documentary, follows former UNT Professor, Dr. Shaun Treat, as he leads a walking ghost tour of downtown Denton, Texas. As the expedition moves from storefront to storefront, each stop elicits a new tale. But, as Dr. Treat points out, the uncertainties of history are the real ghosts. That is, rather than simply presenting a "haunted history" of Denton, it's more accurate to say this movie's center resides at the precipice of a "haunting history." Not all ghost stories need spectres. Sometimes not knowing is ghost enough.

Cette thèse s’attache à mettre en lumière les points de rencontre entre la philosophie épicurienne et l’épopée de Virgile. Si les relations entre la philosophie d’Épicure et l’œuvre de Virgile ont fait l’objet de nombreux développements, les correspondances et les liens mis en lumière concernent pour l’essentiel ses œuvres de jeunesse, soit les poèmes des Géorgiques et des Bucoliques. A contrario, on constate que dans l’épopée d’Énée, les empreintes de l’épicurisme se trouvent bien souvent mises au second plan.Chez Virgile comme chez Lucrèce et les épicuriens, ce qui a trait à la vision et au phénomène des songes tient une place importante. Cette étude envisage de montrer dans quelle mesure le traitement littéraire des différents épisodes de songes et d’apparitions qui rythment l’épopée virgilienne constitue un reflet des considérations épicuriennes qui ont participé à la formation philosophique du jeune poète. La façon dont il aborde le sujet des rêves et des apparitions au travers d’un récit épique codifié se trouve mise en parallèle avec les écrits d’Épicure et plus spécifiquement avec de De rerum natura de Lucrèce. Les questions épistémologiques en lien avec l’épicurisme, de même qu’une analyse du vocabulaire lié aux images et aux songes sont au cœur de ce travail.S’il y avait a priori un enjeu dans le choix d’appréhender une œuvre de l’ampleur de l’Énéide du point de vue de l’épicurisme et en se limitant aux seuls textes traitant des songes et des apparitions, l’analyse des vers de Virgile à la lumière du texte de Lucrèce permet de faire émerger des affinités tant au niveau du lexique que des thématiques traitées. Les empreintes d’une influence épicurienne dans l’épopée de Virgile sont, comme les songes et apparitions, d’une nature parfois ténue, mais si on veut bien y prêter attention, elles ne sont pour autant ni impalpables ni insaisissables. / This thesis aims to highlight links between the epicurean philosophy and Vergil’s epic. If the relations between Epicurus’ philosophy and Vergil’s work have been widely discussed, the highlighted interconnections and links mainly deal with his early works, ie. Georgics and Bucolics. On the other hand, it is possible to note that in Aeneas’ epic the footprint of epicureanism are often put on a second plan.Both as in Vergil and in Lucretius and the Epicureans, the topic dealing with the vision and the dream has an important status. This study aims to demonstrate the way the literary interpretation of the differents episodes of dreams and apparitions, that punctuate Vergil’s epic, is a mirror of the epicurean considerations that took part in the philosophical background of the young poet. The way he deals with the subject of the dreams and the apparitions through a codified epic story is compared with Epicurus’ writings and more specifically with Lucretius’ De rerum natura. Epistemological questions linked with the epicureanism, as well an analysis of the vocabulary refering to images and dreams are the main point of the study.through the epicureanism, limited to the texts dealing with dreams and apparitions, the analysis of Vergil’s verses thanks to Lucretius’ work allows us to highlight affinities in terms of the lexicon as well as the topics covered.The marks of an epicurean influence in Vergil’s epic are, as the dreams and the apparitions, of a tenuous essence, but if we look at this carefully, they are nevertheless neither intangible nor elusive.

Newton's second law, Schrödinger's equation and Maxwell's equations are all theories composed of at most second-time derivatives. Indeed, it is not often we need to take the time derivative of the acceleration. So why are we not seeing more higher-order derivative theories? Although several studies present higher derivatives' usefulness in quadratic gravity and scalar-field theories, one will eventually encounter a problem. In 1850, the physicist Mikhail Ostrogradsky presented a theorem that stated that a non-degenerate Lagrangian composed of finite higher-order time derivatives results in a Hamiltonian unbounded from below. Explicitly, it was shown that the Hamiltonian of such a system includes linearity in physical momenta, often referred to as the ''Ostrogradsky ghost''. This thesis studies how one can avoid the Ostrogradsky ghost by considering degenerate Lagrangians to put constraints on the momenta. The study begins by showing the existence of the ghost and later cover the essential Hamiltonian formalism needed to conduct Hamiltonian constraint analyses of second-order time derivative systems, both single-variable and systems coupled to a regular one. Ultimately, the degenerate second-order Lagrangians successfully eliminate the Ostrogradsky ghost by generating secondary constraints restricting the physical momenta. Moreover, an outline of a Hamiltonian analysis of a general higher-order Lagrangian is presented at the end.

Städte sind Brennpunkte des globalen Wandels. Daher sind hochdetaillierte und aktuelle Informationen über deren Entwicklung nötig, wofür moderne Erdbeobachtungssensoren eine ideale Datenbasis liefern. In der vorliegenden Arbeit wird ein Verfahren zur Änderungserkennung auf Basis höchstaufgelöster optischer Aufnahmen entwickelt und anschließend im stadtgeographischen Kontext zur Bewertung einer potenziell vorliegenden Geisterstadt angewandt. Das unüberwachte objektbasierte Verfahren erfasst den Bau neuer Gebäude mit einer Genauigkeit von 0,8 bis 0,9 entsprechend der Kappa Statistik in einem Testgebiet in der chinesischen Stadt Dongying. Dabei werden Differenzmerkmale auf Basis vorhandener Gebäudegeometrien zur Änderungserkennung verwendet. Ein Vorteil des Ansatzes ist die Nutzung verschiedener Sensoren mit unterschiedlichen Aufnahmegeometrien, was die Verwertung des gesamten Datenbestandes aktueller und zukünftig verfügbarer höchstaufgelöster Satellitenbilddaten auf kleinen räumlichen Skalen ermöglicht. Die Übertragbarkeit des Ansatzes wird mit besonderem Augenmerk auf die Klassenverteilung untersucht. Zu diesem Zweck wird ein Rahmenwerk entwickelt und in zwei Städten unterschiedlicher Charakteristika angewandt. Dabei zeigen sich geringere Genauigkeiten bei ungleich verteilten Klassen im Gegensatz zu einer ausgewogenen Verteilung. Die Bewertung potenziell vorliegender Geisterstädte wird als exemplarische stadtgeographische Anwendung am Beispiel der chinesischen Stadt Dongying gezeigt. Das Bewertungskonzept basiert auf der Annahme, dass eine geringe Auslastung des verfügbaren Wohnraums eines der wichtigsten Merkmale einer Geisterstadt darstellt. Dazu wird ein funktionales 4D-Stadtmodell zur Abschätzung der Bevölkerungskapazität erstellt und anschließend mit der tatsächlichen permanenten Wohnbevölkerung aus Zensusdaten verglichen. Aufgrund signifikanter Unterschiede ergibt sich eine hohe Wahrscheinlichkeit für die Entstehung einer Geisterstadt in der Stadt Dongying. / Cities are hot spots of global change. Thus, highly detailed and up-to-date information is required, which can be delineated based on various earth observation sensors. This thesis aims at the development of a change detection approach based on very high resolution (VHR) optical remote sensing data and consequent exemplary application of the assessment of the ghost city phenomenon in the context of urban geography. The unsupervised object-based change detection method captures the construction of individual buildings with accuracy of 0.8 to 0.9 according to kappa statistics in the city of Dongying, China. The methodology utilizes object-based difference features based on existing building geometries for the delimitation of changed and unchanged buildings. It is capable of handling VHR data from different sensors with deviating viewing geometries which allows the utilization of all present and future available sources of VHR data at small spatial scale. The transferability of the approach is investigated with particular focus on the nature and effects of class distribution. For this purpose, a diagnostic framework is developed and consequently applied in two cities of different characteristics. Results showed that situations of imbalanced class distribution generally provide less reliable identification of changes compared to balanced situations. The assessment of the ghost city phenomenon is conducted as an exemplary application of urban geography in the city of Dongying, China. The conceptual framework replicates undercapacity with respect to the residential population as one of the key characteristics of a ghost city. A 4d functional city model is established based on VHR imagery for population capacity estimation of residential buildings and subsequently related to actual permanent residential population from census counts. A significant mismatch and thus, high likelihood for the emergence and presence of the ghost city phenomenon was found in Dongying.

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Mémoire en recherche-création. / Mon mémoire de recherche-création est un essai qui découle de mes réflexions entourant la création du court-métrage documentaire elle disait je suis eau imprécise (2023). Composée de quatre études de cas sur des films portant sur les grands-mères des cinéastes, la recherche se penche sur la manière dont un film sur une proche « fait mémoire ». J’y analyse les topos communs qui m’ont permis de mieux saisir ce qu’est faire un film sur sa grand-mère. Je m’intéresse ainsi à la façon dont la mémoire parvient à être fixée dans les films par le filmage des gestes des grandsmères (inventés, remaniés) et de leur demeure (maison, jardin), ainsi que par la place que prennent leurs voix. Dans un second temps, guidée par la lecture d’Au bonheur des morts. Récits de ceux qui restent, où la philosophe Vinciane Despret explore les relations entre vivant.es et non-vivant.es, mes analyses se font sous l’angle de la mort au sein de la création. J’évoque la possibilité que, par la fabrication de leur film, les cinéastes construisent des fantômes, puisqu’elles créent des lieux où présence et absence des grands-mères cohabitent et, toujours en suivant une proposition de Despret, je trace les réseaux de collaboration entre grand-mère-personnage et petite-fille-cinéaste. / My creative research thesis is an essay that stems from my reflections surrounding the making of the documentary short "elle disait je suis eau imprécise" (2023) [she said I am imprecise water]. Through an exploration of four distinct film case studies centered on filmmakers' relationships with their grandmothers, my investigation delves into the nuanced process by which a film about a loved one "creates memory." I analyze the common themes that have allowed me to better understand the process of making a film about one's grandmother. I am thus interested in how memory manages to be captured in films through the capturing of the grandmothers' gestures (invented, reworked) and their living spaces (home, garden), as well as the space their voices occupy. In a second step, guided by the reading of "Au bonheur des morts. Récits de ceux qui restent," where the philosopher Vinciane Despret explores the relationships between the living and the non-living, my analyses are conducted from the perspective of death within the realm of creation. I discuss the possibility that through the creation of their films, filmmakers construct ghosts, as they create spaces where the presence and absence of the grandmothers coexist. Towards the end of my thesis, again following a proposal by Despret, I map out the intricate network of collaboration that intertwines the grandmother-character and the filmmaker-granddaughter.

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Studien undersöker de automatiserade testverktygen: Ghost Inspector och Selenium. En limiterad litteraturstudie och två fallstudier görs, för att undersöka och utvärdera testverktygen. Detta för att kunna tillgodose riktlinjer som är användbara, vid val av ett verktyg för att utföra regressionstestning på webbapplikationer.IStone använder Ghost Inspector som verktyg vid regressionstest på webb applikationer, eftersom det ger dem en effektiv konfigurering och underhålls- process. Selenium kräver mer ansträngning för konfigurering och underhåll, eftersom verktygen inte är en tjänst. Miljön i Ghost Inspector underlättar för iStone att exekvera test kontinuerligt och förser projektteamet med det senaste testresultatet. / The study evaluates the automatic testing tools: Ghost Inspector and Selenium. and focuses on comparing them in terms of the set up and maintenance processes. The study includes a limited literature study and two case studies. The purpose is to evaluate the tools and provide guidelines for choosing a regression testing tool when testing the functionality of web applications.IStone use Ghost Inspector as regressions testing tool on web applications, since it offers an effective set up and maintenance process. Selenium requires more effort to set up and maintain, since Selenium is not a service. The Ghost Inspector environment comforts iStone with the ability of executing test continuously and supplies the latest test results to the project team.

The dynamics of a complex system can be understood by analyzing the phase space structure of that system. We apply geometric and statistical techniques to two Hamiltonian systems to find and exploit structure in the phase space that helps us get qualitative and quantitative results about the phase space transport. While the structure can be revealed by the study of invariant manifolds of fixed points and periodic orbits in the first system, there do not exist any fixed points (and hence invariant manifolds) in the second system. The use of statistical (or measure theoretic) and topological methods reveals the phase space structure even in the absence of fixed points or stable and unstable invariant manifolds. The first problem we study is the four-body problem in the context of a spacecraft in the presence of a planet and two of its moons, where we exploit the phase space structure of the problem to devise an intelligent control strategy to achieve mission objectives. We use a family of analytically derived controlled Keplerian Maps in the Patched-Three-Body framework to design fuel efficient trajectories with realistic flight times. These maps approximate the dynamics of the Planar Circular Restricted Three Body Problem (PCR3BP) and we patch solutions in two different PCR3BPs to form the desired trajectories in the four body system. The second problem we study concerns phase space mixing in a two-dimensional time dependent Stokes flow system. Topological analysis of the braiding of periodic points has been recently used to find lower bounds on the complexity of the flow via the Thurston-Nielsen classification theorem (TNCT). We extend this framework by demonstrating that in a perturbed system with no apparent periodic points, the almost-invariant sets computed using a transfer operator approach are the natural objects on which to pin the TNCT. / Ph. D.