Дисертації з теми "Light motion"

La interacció de la llum confinada en una cavitat òptica amb els graus de llibertat mecànics de la matèria en els sistemes optomecànics permet la investigació fonamental en física mesoscòpica i el desenvolupament de microdispositius d’alt rendiment com sensors o processadors de senyals òptics. La dinàmica d’aquests sistemes queda determinada per un conjunt petit de paràmetres els valors dels quals poden ser controlats per disseny. Per una altra banda, les imperfeccions que resulten dels processos de nano-fabricació fan del seu control un repte en estructures nanomètriques com els cristalls optomecànics. Això imposa límits severs en els sistemes d’última generació, fent que el desordre sigui considerat perjudicial. Tot i això, la interacció entre ordre i desordre en la dispersió múltiple de la llum ofereix una ruta alternativa per confinar fortament la llum. Aquest procés es coneix com a localització d’Anderson, un fenomen originalment descrit per als electrons en la física de l’estat sòlid. En principi, el mateix passa amb les ones elàstiques (fonons), conduint a modes de vibració mecànics estretament localitzats. Tot i això, no s’ha observat directament la localització d’Anderson en fonons d’alta freqüència, ja que són difícils d’excitar i la seva radiació de camp llunyà és limitada. Es pot utilitzar cavitats òptiques d’Anderson com a sonda local per estudiar la localització per desordre de les ones acústiques? Quina és la probabilitat de trobar fotons i fonons espacialment colocalitzats? Són aquestes dues ones igualment sensibles a les imperfeccions de fabricació? Podem manipular, via la pressió de radiació, la dinàmica d’un mode mecànic en un sistema d’aquest tipus? Aquestes preguntes científiques articulen aquesta tesi. Per respondre a aquestes preguntes, hem identificat dos requisits principals. El primer és l’ús de cavitats òptiques d’alt factor de qualitat (Q), ja que la transducció del moviment escala amb Q. El segon és el grau de superposició entre els camps localitzats, ja que els modes acústics i òptics apareixen en posicions no correlacionades. El primer requisit es compleix en guies d’ona de cristall fotònic, on observem localització d’Anderson òptica amb Q de fins a 100000. Mitjançant aquests modes òptics, demostrem la transducció de desplaçaments mecànics en dos rangs de freqüència: modes mecànics de tota l’estructura suspesa, amb freqüències entre 100 i 500 MHz, i modes mecànics guiats d’alta freqüència (~7 GHz). En tots dos casos, la llum confinada en les cavitats permet amplificar el seu desplaçament fins que les oscil·lacions són coherents i autosostingudes. En la banda de 7 GHz, el sistema que hem explorat constitueix una plataforma perfecta per observar fenòmens de localització de fonons d’alta freqüència. No obstant això, aquestes guies optomecàniques en cristalls bidimensionals no tenen cap mecanisme que garanteixi a priori un alt grau de colocalització. Per evitar aquest problema, estudiem numèricament un altre sistema basat en reflectors distribuïts de Bragg unidimensionals compostos per GaAs i AlAs. Es demostra una millora estadística de l’acoblament optomecànic, g, pel qual el sistema esdevé un candidat prometedor per observar la localització d’Anderson de fonons a 20 GHz mitjançant espectroscòpia de fonons coherents en experiments de bombament-sondeig. Utilitzem aquesta tècnica experimental per excitar i detectar una nano-cavitat creada a la interfície de dues multicapes acústiques perfectament periòdiques. Aquest estat topològic 0-dimensional constitueix un banc de proves per a comprendre les implicacions més bàsiques de les propietats topològiques dels cristalls en les seves superfícies i interfícies. Finalment, analitzem numèricament el cas de les guies d’ona topològiques, quantificant el seu potencial per al transport de fotons sense dissipació, una premissa pel desenvolupament de cavitats i circuits optomecànics més compactes i eficients.
La interacción de la luz confinada en una cavidad óptica con los grados de libertad mecánicos de la materia en los sistemas optomecánicos permite la investigación fundamental en física mesoscópica y el desarrollo de micro-dispositivos de alto rendimiento para aplicaciones como sensores o el procesamiento de señales ópticas. La dinámica de tales sistemas queda determinada por un conjunto pequeño de parámetros cuyos valores pueden controlarse por diseño. Sin embargo, su control se vuelve un desafío en estructuras nanométricas como los cristales optomecánicos debido a imperfecciones inevitables durante la nano-fabricación. Esto impone límites severos en los sistemas de última generación y el desorden es considerado perjudicial. No obstante, la interacción entre orden y desorden en el esparcimiento múltiple de la luz ofrece una ruta alternativa para confinar fuertemente la luz. Este proceso se conoce como la localización de Anderson, un fenómeno originalmente descrito para los electrones en la física del estado sólido. En principio, lo mismo ocurre con las ondas elásticas (fonones), conduciendo a modos mecánicos estrechamente localizados. Sin embargo, no se ha observado directamente la localización de Anderson en fonones de alta frecuencia dada la dificultad de generarlos y a su limitada radiación de campo lejano. ¿Se puede utilizar cavidades ópticas de Anderson como sonda local para estudiar la localización por desorden de las ondas acústicas? ¿Cuál es la probabilidad de encontrar fotones y fonones espacialmente colocalizados? ¿Son estas dos ondas igualmente sensibles a las imperfecciones de fabricación? ¿Podemos manipular, vía la presión de radiación, la dinámica de un modo mecánico en un sistema de este tipo? Estas preguntas científicas articulan esta tesis. Para responder a estas preguntas, identificamos dos requisitos principales. El primero es el uso de cavidades ópticas de alto factor de calidad (Q), ya que la transducción del movimiento escala con Q. El segundo es el grado de superposición entre los campos localizados, ya que los modos acústicos y ópticos aparecen en posiciones no correlacionadas. El primer requisito se logra en guías de onda de cristal fotónico, donde observamos localización de Anderson óptica con Q de hasta 100000. Mediante estos modos ópticos, demostramos la transducción de desplazamientos mecánicos en dos rangos de frecuencia: modos mecánicos de toda la estructura suspendida, con frecuencias entre 100 y 500 MHz, y modos mecánicos guiados de alta frecuencia (~7 GHz). En ambos casos, la luz confinada en las cavidades permite amplificar su desplazamiento hasta que las oscilaciones son coherentes y autosostenidas. En la banda de 7 GHz, el sistema que exploramos constituye una plataforma perfecta para observar fenómenos de localización de fonones de alta frecuencia. Sin embargo, estas guías optomecánicas en cristales bidimensionales carecen de cualquier mecanismo que garantice a priori un alto grado de colocalización. Para evitar este problema, estudiamos numéricamente otro sistema basado en reflectores distribuidos de Bragg unidimensionales compuestos por GaAs y AlAs. Se demuestra una mejora estadística del acoplamiento optomecánico, g, lo que convierte a este sistema en un candidato prometedor para observar la localización de Anderson de fonones a 20 GHz mediante espectroscopia de fonones coherentes en experimentos de bombeo-sondeo. Utilizamos esta técnica experimental para excitar y detectar una nano-cavidad creada en la interfaz de dos multicapas acústicas perfectamente periódicas. Este estado topológico 0-dimensional constituye un banco de pruebas para comprender las implicaciones más básicas de las propiedades topológicas de los cristales en sus superficies e interfaces. Por último, analizamos numéricamente el caso de las guías de onda topológicas, cuantificando su potencial para el transporte de fotones sin disipación, una premisa para el desarrollo de cavidades y circuitos optomecánicos más compactos y eficientes.
The interaction of light trapped in an optical cavity and motional degrees of freedom in cavity optomechanical systems has emerged as a mechanism enabling both fundamental research in mesoscopic quantum physics and high-performance microscale devices for applications such as sensing or optical signal processing. The dynamics of such systems are reduced to a small set of governing parameters that can be engineered by design. Nevertheless, control over these parameters becomes challenging in nanometer-scale structures like optomechanical crystal cavities due to unavoidable fabrication imperfections. This imposes severe limits in state-of-the-art systems and disorder is seen as a nuisance. In this thesis, we propose instead to harness its potential. In a disordered lattice, the interplay between order and disorder in multiple scattering offers an alternative route to confine light, i.e., Anderson localization, a phenomenon well known for electrons in solid-state physics. In principle, the same phenomenon happens for elastic waves (phonons), leading to tightly localized mechanical modes. However, direct observation of Anderson localization of phonons in the GHz range remains elusive, due to the lack of practical phonon transitions in the solid state and limited far-field radiation for read-out. Can we use disorder-induced optical cavities to locally probe Anderson localization of GHz mechanical vibrations via their optomechanical interaction? What is the likelihood to find spatially co-localized photons and phonons? Are these two waves equally sensitive to fabrication imperfection? Can we manipulate, via light, the mechanical degrees of freedom in such a system? These scientific questions articulate this thesis. In order to answer these, two main requirements are identified. The first is exploring high quality factor (Q) optical cavities, since the transduction of mechanical motion scales with it. The second is the level of overlap between the localized fields, i.e. the statistical level of co-localization, since acoustic and optical modes appear at uncorrelated positions due to their complex interference nature. The first requirement is achieved in both standard and slotted slow-light photonic crystal waveguides, where we observe high-Q ( up to 100000) optical Anderson localization. In particular, one of the designs simultaneously operates as a phononic waveguide. We demonstrate transduction of thermally-activated motion via Anderson-localized optical modes in slotted photonic crystal waveguides at two frequency ranges: low-frequency in-plane mechanical modes spanning 100-500 MHz and high-frequency ~7 GHz guided mechanical modes. At both frequency ends, the light field is used to amplify mechanical motion up to coherent self-sustained oscillations. At the 7 GHz band, the explored system constitutes a perfect platform to observe high-frequency phonon localization phenomena. However, these two-dimensional optomechanical crystal waveguides lack any a priori mechanism that guarantees a high degree of co-localization. To circumvent this issue we propose using periodic-on-average one-dimensional GaAs/AlAs Distributed Bragg Reflectors. A statistical enhancement of the vacuum optomechanical coupling rate, g, is found, making this system a promising candidate to explore Anderson localization of even higher frequency (~20 GHz) phonons using ultra-fast pump-probe coherent phonon spectroscopy. We use this experimental technique to all-optically probe a spacer-less phononic nanocavity created by concatenating two perfectly periodic multilayers, i.e., a 0D topological state, a testbed to understand the most basic implications of bulk topology on interfaces. Last, we explore their propagating counterpart, topological interface waveguides and quantify their potential for robust backscattering-free photon transport at the nanoscale, a premise for compact and efficient circuit and cavity optomechanics based on topological edge states.
Universitat Autònoma de Barcelona. Programa de Doctorat en Física

Phase Measuring Profilometry (PMP) is the most robust scanning technique for static 3D data acquisition. To make this technique robust to the target objects which are in motion during the scan interval a novel algorithm called ‘Pattern Interleaving’ is used to get a high density single scan image and making Phase Measuring Profilometry insensitive to ‘z’ motion and prevent motion banding which is predominant in 3D reconstruction when the object is in motion during the scan time

Recent advancements in laser technology are quickly moving the frontiers of research: quantum dynamics can now be investigated in more detail, on new timescales, with an unprecedented level of control. These new possibilities offer a new ground for the theoretical study of fundamental processes; at the same time, a proper understanding of phenomena involved is necessary to explain measurements, and to indicate directions for further experiments. This Thesis deals with the theoretical investigation of particular cases of light-matter interaction, in atoms and in dielectrics. Regimes considered here have just become a subject of intensive investigation: they are acquiring more and more relevance as technological advancements make them experimentally accessible. In the first part of the Thesis I consider a process as fundamental as the single-photon ionization of atoms: my modeling will include an ultrashort pulse (full width half maximum ~ 100 as = 10^-16 s) exciting an electron to the continuum, and a strong few-cycle near-infrared laser field. This configuration is suitable to reproduce recent streaking experiments on atoms. I developed a numerical tool to simulate these dynamics in three dimensions: the process is quite elaborate and requires an adequate description of multi-electron atoms. With proper approximations I was able to calculate photoelectron spectra using just a few dipole matrix elements, which were obtained with the aid of our external collaborators, from refined atomic structure calculations. The results of our relatively simple tool are in very good agreement with more sophisticated numerical calculations. In addition to that, I discuss my contribution to the theoretical support of a fundamental experiment [I]: both simulations and measurements indicate a delay between two different channel of photoemission in neon. A careful investigation of the limit of validity of approximations employed reveals that the Coulomb-Volkov approximation is not suitable to describe fine details of the interaction with the laser pulse. I also report on our analysis of experimental data from angle-resolved attosecond streaking. The second part of the Thesis is devoted to the investigation of inter-band excitations in dielectrics; driving this process with a high degree of control is on the edge of current technology. The ultrafast creation of charge carriers in an insulator is intriguing: dielectric properties of the medium change drastically, revealing features of the peculiar electron dynamics in such a situation. I have simulated this process solving the time dependent Schroedinger equation for a single electron in a one-dimensional lattice and analyzed how the charge Q displaced during the interaction with the pulse depends on laser parameters. These calculations reproduce to a good extent the behavior observed in the experiment. Both the theory and the experiment point out a strong dependence of Q on laser parameters: this promises a high degree of control, and at the same time suggests the possibility of a solid-state device to characterize an optical pulse. I also study in detail the modification occurring in the electric response of the sample to the electric field. The purpose of this analysis is to identify some features directly related to dynamics of newly created charge carriers. During my investigation of electron dynamics during an excitation process, I have often faced the difficulty to identify quantities which might resemble eigenstates of the time-dependent Hamiltonian. Similar field-dressed states would describe the distortion due to the field, of eigenstates of the field-free Hamiltonian. A proper definition of field-dressed states would allow a correct interpretation of the wavefunction in terms of instantaneous excited population, which is otherwise impossible to define.
Neueste Fortschritte im Bereich der Lasertechnologie erweitern schnell die Grenzen der Forschung. Quantendynamiken koennen genauer den je untersucht werden, aus kuerzeren Zeitskalen und mit einer hoeheren Kontrollebene. Diese Entwicklung bietet neue Moeglichkeiten, fundamentale Prozesse theoretisch zu untersuchen; darueber hinaus ist ein Verstaendnis der zu Grunde liegenden physikalischen Vorgaenge erforderlich, um Messresultate zu erklaeren und moegliche Richtungen fuer kuenftige Experimente aufzuzeigen. Diese Doktorarbeit befasst sich mit der theoretischen Analyse bestimmter Licht-Materie-Wechselwirkungen in Atomen und Dielektrika. Die im Rahmen dieser Thesis untersuchten Bereiche sind aktuell Thema intensiver Forschung. Dank weiterer technologischer Entwicklungen, die Experimente in diesen Bereichen ausfuehrbar machen, gewinnen sie immer weiter an Relevanz.Neueste Fortschritte im Bereich der Lasertechnologie erweitern schnell die Grenzen der Forschung. Quantendynamiken koennen genauer den je untersucht werden, aus kuerzeren Zeitskalen und mit einer hoeheren Kontrollebene. Diese Entwicklung bietet neue Moeglichkeiten, fundamentale Prozesse theoretisch zu untersuchen; darueber hinaus ist ein Verstaendnis der zu Grunde liegenden physikalischen Vorgaenge erforderlich, um Messresultate zu erklaeren und moegliche Richtungen fuer kuenftige Experimente aufzuzeigen. Diese Doktorarbeit befasst sich mit der theoretischen Analyse bestimmter Licht-Materie-Wechselwirkungen in Atomen und Dielektrika. Die im Rahmen dieser Thesis untersuchten Bereiche sind aktuell Thema intensiver Forschung. Dank weiterer technologischer Entwicklungen, die Experimente in diesen Bereichen ausfuehrbar machen, gewinnen sie immer weiter an Relevanz. Im ersten Teil der Arbeit beschreibe ich den fundamentalen Prozess der atomaren Ionisation durch ein einzelnes Photon. Mein Model enthaelt einen ultrakurzen Lichtpuls mit einer Halbwertsbreite von ~ 100 as = 10^-16 s, der ein Elektron in das Kontinuum anregt, sowie einen starkes Laserfeld im nahen infraroten Spektralbereich mit wenigen Zyklen. Diese Konfiguration erlaubt die Nachbildung von neuesten Streaking Experimenten an Atomen. Ich habe ein numerisches Werkzeug entwickelt, um diese Dynamiken in drei Dimensionen zu simulieren. Der Prozess ist sehr komplex und bedarf einer hinreichenden Beschreibung von Atomen mit mehreren Elektronen. Unter Beruecksichtigung geeigneter Naeherungen war es mir moeglich, Photoelektronenspektren mit Hilfe nur weniger Dipolmatrixelemente zu berechnen, welche in Zusammenarbeit mit unseren externen Kollaborationspartner durch verfeinerte Atomstruktur-Berechnungen bestimmt wurden. Die Ergebnisse unseres verhaeltnismaeßig einfachen Vorgehens stimmen in einem hohen Grad mit fortgeschritteneren numerischen Methoden ueberein. Darueber hinaus diskutiere ich meinen Beitrag zur theoretischen Unterstuetzung eines grundlegenden Experiments. Sowohl Simulationen als auch Messungen weisen auf eine Verzoegerung zwischen zwei Photoemissionskanaelen in Neon hin. Eine sorgfaeltige Pruefung der Gueltigkeit der verwendeten Naeherungen verraet, dass die Coulomb-Volkov Naeherung nicht geeignet ist, um feine Einzelheiten in der Wechselwirkung mit dem Laserpuls zu beschreiben. Außerdem berichte ich ueber unsere Analyse der Messdaten der winkelaufgeloesten Attosekunden Streaking Experimente. Der zweite Teil der Thesis widmet sich der Untersuchung von Interband-Anregungen in Dielektrika. Die kontrollierte Lenkung dieser Ue bergaenge wurde erst mit aktuellster Technologie ermeoglicht. Die ultraschnelle Erzeugung von Ladungstraegern in einem Isolator ist bemerkenswert. Die dielektrischen Eigenschaften aendern sich dramatisch, was Rueckschluesse auf die Elektronendynamik waehrend dieser Anregung zulaesst. Ich habe diesen Prozess durch Loesung der zeitabhaengigen Schroedingergleichung fuer ein einzelnes Elektron in einem eindimensionalen Gitter simuliert und untersucht, wie sich die waehrend des Lichtpulses verlagerte Ladung mit den Laserparametern aendert. Diese Berechnungen reproduzieren in hohem Maße das im Experiment beobachtete Verhalten. Sowohl Theorie als auch Experiment weisen auf eine starke Abhaengigkeit der Ladung von den Laserparametern hin. Dies verspricht ein hohes Maß an Kontrolle und deutet auf eine moegliche Anwendung eines Festkoerperbauelements fuer die Charakterisierung eines optischen Pulses hin. Außerdem untersuche ich detailliert die Modifikationen der elektrischen Antwort des Samples auf ein externes elektrisches Feld. Das Ziel dieser Analyse ist die Identifikation einiger Eigenschaften die direkt mit der Dynamik der erzeugten Ladungstraeger zusammenhaengen. Waehrend der Untersuchung der Elektronendynamiken in einem Anregungsprozeß, stieß ich oft auf die Problematik, Groeßen zu ermitteln, die Eigenzustaenden des zeitabhaengigen Hamilton- Operators aehneln koennten. Aehnliche “Field-dressed States” wuerden die Verzerrung der Eigenzusteande des feldfreien Hamiltonoperators aufgrund des Felds beschreiben. Eine geeignete Definition der Field-dressed States wuerde eine korrekte Interpretation der Wellenfunktion in Abhaengigkeit der instantanen angeregten Besetzung ermoeglichen, welche sich auf anderem Wege nicht bestimmen laesst.

Talmy (1975, 1985, 1991 and 2000b) studies Motion events encoded by verbs from the perspective of lexicalisation(T). Talmy (2000b) proposes six basic semantic elements to describe Motion events; they are Figure, Motion, Path, Ground, Manner, and Cause. For example, in the sentence He entered the room, enter is the main verb and encodes Motion “move” and Path “into”. So the main verb encodes the Path information. Such phenomena are very common in Spanish; however, in English and in Chinese Path is usually expressed by satellites, a category of surface element. Enter is exceptional in English. Although it is a word in English it was borrowed from French. The surface elements which encode the Path information determine a language’s type. For example, if Path is encoded by main verbs in language A, then this language A is a verb-framed language; if Path is typically expressed by satellites in language B, then language B is a satellite-framed language. These are the two most widespread types of languages in this typology. According to Talmy, English is a satellite-framed language (S-framed language); Spanish a verb-framed language (V-framed language); and Chinese a satellite-framed language. Slobin (1996, 1997, 2002, 2004 and 2006) argues that Chinese is an equipollent-framed language (E-framed language), a third language type he added to Talmy’s typology. The evidence for this is the serial verb construction (SVC) in Chinese. SVCs can be briefly defined as a syntactic pattern where two or more verbs are used together to express a single conceptual event and there are no markers of subordination and coordination. Slobin uses feī chū (fly exit) as an example of the SVC and he insists that feī (fly) and chū (exit) share the same grammatical status and are equal to each other in that neither of them can be omitted for a complete expression of the event of flying out. The first verb encodes the Manner information and the latter one expresses the Path information. Omitting either part, the expression is ungrammatical. Having briefly reviewed these two models of language typology, many questions have arisen. Is it necessary to have a third language type to account for Chinese? Or is Chinese an Eframed language or a S-framed language? What is the language typology of Chinese? This is the main research question I aim to answer in this thesis. The main question concerns the nature of Chinese SVCs. In my thesis, I discuss the features of Chinese SVCs as preparation for a working definition of SVC for my empirical work to collect the SVC data from the Lancaster Corpus of Mandarin Chinese (LCMC). I show that the components in Chinese SVCs are not equal in semantics. There are constraints on the positions for different semantic parameters. In addition, the surface forms of components for SVCs do not share equal status for the asymmetrical SVCs. This further shows that components within Chinese SVCs are not in equal grammatical status. My data shows that Path can be encoded by main verbs as well as by satellites in Chinese. Having illustrated that Chinese SVC is not evidence for Chinese to be an E-framed language, then, is Chinese a S-framed language similar to English or a V-framed language like Spanish? Özçalışkan (2004) claims that Path verbs, verbs encoding [Motion + Path], is a closed class. How many Path verbs are there in Chinese and are these Path verbs comparable with those in English and in Spanish? I give a comprehensive list of Chinese Path verbs and then focus on some of them to track the process of the lexicalisation(T). I found that there are no significant differences in number for the 13 types of Path verbs in Chinese, English and Spanish and that the lexicalised(T) Path is comparable. These findings indicate that Chinese uses both main verbs and satellites to express the Path information in motion events. Additionally, the grammaticalization trend of Chinese Path verbs and the shift from independent Path verbs into Path satellites and grammatical relation markers also show that Chinese is not part of any of the parallel system, the split system, or the intermixed system for expressing motion events. Chinese is in the transferring period from a S-framed language to a V-framed language.

It is well known that light, the fastest entity in the universe, moves at a staggering speed of 300 million meters per second. The ability to stop its flight on a centimetre scale or lower requires a detector with temporal resolution of around a hundred picoseconds. Freezing light in motion at this scale is a feat worth achieving, as it leads to a variety of exciting applications, from observing dynamical light phenomena to measuring distances and depths with high precision, as in LIDAR technology. In the past decades, different technologies have been developed to image light in motion; in this thesis, we propose a new method that exploit a recently-developed single-photon detector technology to capture movies of light in motion at very low intensity levels. We use this method to develop novel imaging applications and detection techniques. In particular, this thesis reports on the observation and study of dynamical light phenomena such as laser propagation in air, laser-induced plasma, propagation in optical fibres and slow light. We also show how the ability to record light in motion can be used to capture light signals scattered from around an obstacle, leading to the ability to locate and track moving objects hidden from view.

Whether we live in a concrete jungle or somewhere a little morerural, we probably still spend a good deal of our time behind wallsand under roofs, forever building barriers between what we thinkis ours and the rest of the world, out there. Never in time have ourown motion in our world been as swift as it is today, never have wefenced ourself off from what is naturally occurring and had the abilityto manicure our environment more. The thesis sought out to bringthe feeling of stillness and silence that exist in a natural landscapefilled with both ambient motion and sound, inside. To add qualitiesto a room where both contemplation and activation can take place.The thesis covers a study on perception and different motions (bothphysical and visual) in nature with focus on the slow movement ofwater. 6 people were asked to evaluate the calming qualities of 22video sequences; each showing abstract water motion, and fromthe evaluation derive patterns of motion preferences. The studymotivated the development of a set of principles meant to be usedby lighting designers to create and shape an overall activating andcaptivating space, and generated design ideas for a sculpturalroom element with internal physical movement and light shifts, withthe purpose of bringing motion in to a static environment. A mock-upwas built to test the idea of a connection between wellbeing andnatural, expected but unforeseen motion.This is my ontological interpretation and take on dynamic lighting

Thesis (M.S. in Applied Mathematics)--Naval Postgraduate School, September 2009.
Thesis Advisor(s): Borges, Carlos F. ; Olsen, Richard C. "September 2009." Description based on title screen as viewed on 6 November 2009. Author(s) subject terms: LIDAR, Monte Carlo simulation, full-waveform, model. Includes bibliographical references (p. 105-108). Also available in print.

In this thesis we propose a solution to how a system can find and track people, as well as recognizing their gestures, in a $360^\circ$ field of view using consumer grade products. We describe a system connecting multiple depth cameras in an array and have them operate as a single camera controlled by a single computer. Using a single camera providing features such as detection, tracking and recognizing gestures of people, we specifically focus on the difficulties of preserving these features in moving forward to an array of cameras. We propose a solution based on Microsoft Kinect and Kinect SDK, using linear transformation to account for a fixed camera model to combine skeleton data from an array of Kinect sensors. Furthermore, we use positional based identification to determine whether people are being tracked by another camera in the system. The contributions of this work include insight into the challenges of building this kind of system based on Kinect hardware and software intended for use on a single computer, such as performance bottlenecks, along with possible alternative solutions. In particular, we present performance measurements for a single computer running up to four sensors and show a system that can run satisfactorily with up to at least 5 sensors on today's computers. We show what requirements on hardware can be expected for such a system, as well as where there are potential limits as the number of sensors increase.
Music in Motion

This thesis deals with the image of the prostitute in four films: Klute (1971) Pretty Baby (1978) McCabe and Mrs. Miller (1972) and American Gigolo (1980). It includes a review of the image of the prostitute in art and literature in the eighteenth and nineteenth centuries. These earlier images are compared and contrasted with the images presented in the four films and used to analyze how women are represented through the role of the prostitute in Klute, Pretty Baby and McCabe and Mrs. Miller. American Gigolo presents male prostitution in a manner conventional to prostitution, but unconventional in terms of representing men. American Gigolo provides a contrast for the three other films in terms of both gender and the image of the prostitute.

Dans la nature, des moteurs moléculaires tells que l'ATP synthase ou la kinésine peuvent consommer de l'énergie pour générer du mouvement et ainsi assurer des fonctions essentielles comme le transport ou la synthèse de molécules. La préparation de moteurs artificiels capables de fournir un travail à différentes échelles est un défi important pour les chimistes. Dans ce travail, nous avons conçu et synthétisé de manière stéréosélective un moteur moléculaire unidirectionnel et hautement fonctionnalisé à l'échelle du gramme. La fonctionnalisation orthogonale du moteur permet de l'intégrer dans des matériaux polymères. Grâce à une réaction de "click" réalisée sous différentes conditions de dilution, nous avons pu obtenir soit une macromolécule bicyclique en forme de 8 soit un gel de polymers dont les moteurs constituent les points de réticulation. Sous irradiation UV, les moteurs tournent ce qui enroule les chaines de polymers. Pour le bicycle, la taille caractéristique de la macromolécule diminue tandis que la morphologie évolue vers une pelote étirée. Dans le cas du gel, suite à la rotation des moteurs, l'enroulement des chaines conduit à une contraction du gel de l'ordre de 80% en volume. C'est le premier exemple d'intégration de mouvements moléculaires hors équilibre résultant en une réponse observable à l'échelle macroscopique. Ce travail ouvre des perspectives intéressantes dans le domaine des nanotechnologies ainsi que dans celui de l'énergie
Natural molecular motors such as ATP synthase, myosin, kinesin and dynein can convert conformationalchanges, due to chemical energy input, into directed motion for catalysis and transport. Preparing artificial molecular motors and making them work at different scales (from nano to macroscopic scale) have been long-term challenges. Herein we designed and synthesized a light driven rotary molecular motor in highly enantiopure form and in gram scale. This motor is featured by two orthogonal functionalities on its upper and lower part, allowing its further integration into polymeric materials. By performing click reaction under different concentration conditions, either an eight shaped motor-polymer conjugate or a gel containing motors as reticulation units could be obtained. Upon UV irradiation, the polymer chains could be entangled due to the rotation of this motor. For eight shaped polymer, the dimension was changed towards smaller dimension, and the morphology was changed from cycle to collapsed coils (spherical or more elongated). For the gel, due to the twisting of polymer chains induced by the rotation of the motor, it could be contracted significantly (80 %) compared with its original volume. The integration of machines which display motions out of equilibrium at nanoscale to movement in the macroscopic world which is extensively used in natural systems will open very interesting prospects in nanotechnology for further developments

The ability to recognise the movements made by humans and other animals, referred to as biological motion, is a specialised human ability that develops at an early age. This perceptual ability is strong even for the minimal amount of information contained in a point-light display, which has been used to study specific features of biological motion to find out what properties contribute to this ability. The perception of biological motion depends on visual perception, visual attention and motor cognition, and perception depends both on the global form, configural information and local information of a body in motion. Depending on the situation, either global or local motions will be more salient and processed to a greater extent by the perceptual system. Previous research has shown that the local and configural information contained in the feet play an important role for identification, direction discrimination and the inversion effect. The salience of the feet for perception has previously been studied when they are subjected to focused attention, but not reflexive attention. The goal of this study was to investigate if the local and configural information of the feet can trigger reflexive attention and be incidentally processed by the visual system in a direction discrimination task. To test this experimentally, a masking paradigm was used where the feet were placed in a mask consisting of scrambled walkers. The results show that the feet affect recognition of target direction when the target is upright, but not when inverted. An interesting and unexpected finding was that for upright targets, the feet aid recognition when they move in the opposite direction of the target. Due to the experimental setup, it is difficult to say with certainty what the results imply, and suggestions for a follow-up study are presented.
Kognitionsvetenskap handlar om hur människor tänker, uppfattar världen och interagerar med omgivningen och med andra människor. Inom kognitiv psykologi har människors förmåga att uppfatta andra människors och djurs rörelser studerats länge. Vi kan känna igen vänner och familj på det unika sätt som de rör sig och forskningen har visat att vi har förmågan att identifiera många olika typer av rörelser och handlingar även när den tillgängliga informationen är minimal. Studier som använt s.k. punktljusdisplayer, där endast vita punkter som representerar kroppens stora leder visas mot en svart bakgrund, har visat att förmågan att känna igen biologiska rörelser är mycket känslig och robust för störningar. Forskare har undersökt vilken information hos rörelser som vi använder för att lyckas med detta, och hur visuell perception och uppmärksamhet fungerar då vi tittar på punktljusdisplayer. Det har visat sig att fötterna har en stor inverkan på igenkänning av rörelseriktning och att det framförallt är på grund av fötterna som det är svårt att känna igen rörelser som presenteras uppochner. Något som inte har testats tidigare är om fötterna är så starka signaler att de kan påverka vår perception även om vi inte riktar fokuserad uppmärksamhet mot dem, utan endast reflexiv uppmärksamhet. Den här studien har testat om fötter kan trigga just reflexiv uppmärksamhet och påverka hur vi känner igen rörelseriktningen hos en gående punktljus-figur. Resultaten visar att fötternas specifika rörelsemönster kan trigga reflexiv uppmärksamhet i situationer då rörelserna är upprätta och då fötterna rör sig i motsatt riktning från den figur som deltagare fokuserar på. Experimentdesignen har dock inneburit att resultaten är svåra att tolka. För att säkrare kunna säga huruvida resultaten beror på fötterna föreslås en ny studie, och detaljer kring vilka justeringar som borde göras i en sådan studie presenteras.

Paris is one of the key sites of meaning regarding France's cinematic output. This thesis surveys the contribution German émigré filmmakers made to the French cinema of the 1930s through a series of case studies of their depiction of the nation's capital city. It argues that this contribution was both typical and singular. The émigrés engaged directly with traditions of Parisian representation, but they also played a distinctive role in the important debate over the direction early French sound filmmaking should take. The body of the thesis contains detailed textual analysis of many émigré productions which have hitherto been ignored within film history. It contextualises this analysis with comparative discussion of films made by indigenous professionals and an examination of past and present intertextual aspects of Parisian culture. The thesis moves beyond aesthetic concerns to also consider the political, industrial and social significance of the work of the émigré Filmmakers. The reception of their films is located within a history of the Franco-German relationship as a whole. By drawing widely upon supporting documentation in critical and trade journals of the time, the thesis provides a new history of a crucial transitional point in the development of European film culture.

A single light sphere is placed inside of a drum completely filled with a viscous fluid. the drum rotates perpendicular to gravity such that the Reynolds number remains small. In this flow configuration there is a wide range of behaviours. We have measured eccentric fixed points, circular orbits and asymmetric orbits by the walls of the drum. A full description of these phenomena is given as a function of the size of the sphere. We have also studied the case of a porous sphere and compared it the solid case. Finally we have studied the effect of roughness on this system.

Thesis (M.S.)--Miami University, Dept. of Physics, 2005.
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Ända sedan filmbranschen började implementera datorgenererat innehåll i filmproduktioner har 3D blivit en större del av vår vardag. Syftet med detta arbete är att hjälpa 3D-artisten att optimera sitt arbetsflöde för att effektivisera en annars tidskrävande teknisk process. Genom att visuellt analysera och därefter kategorisera befintliga animationer av olika 3D-logotyper, har detta arbete skapat en grund till att kartlägga hur en eventuell plugin med förinställda ljussättningar bäst möter funna kategorier. För att besvara arbetes frågeställningar utfördes en visuell innehållsanalys av 50 3D-animationer. De analyserade logotyperna valdes ut från urvalskategorierna: film och bil. Arbetets resultat tyder på att det finns återkommande stilar och metoder för ljussättning av motion graphics. Funna kombinationer för ljussättningar har inte kunnat kategoriseras då resultaten från analysen ej gav upphov till mer än en ljussättning. Resultaten ger en grund för en optimal ljussättning ämnad för en plugin i Cinema 4D. Studien ger även förslag på fortsatt forskning inom området.
Ever since the film industry started implementing computer generated content in film productions the presence of 3D in our everyday life has increased. The purpose of this study is to help the 3D artists optimize their workflow and streamline a time-consuming technical task. Through visually analyzing and further categorizing existing logotype animations this study has created a foundation towards mapping how a potential plug-in with predefined lighting setups best matches found categories. To answer the questions of this study a visual content analysis was conducted during which 50 3D animations were analyzed. The analyzed logotypes were chosen from the categories: film and cars. The findings of this study suggest that there are reoccurring styles and methods for lighting in motion graphics. The study has not been successful categorizing the most commonly used lighting setups due to the analysis not resulting in more than one lighting setup. The result provides a foundation for an optimal setup for lighting in motion graphics. The study also provides suggestions for future research on the subject.

Research on biological motion, using point-light displays to present the motions, have been unravelling what information factors are still embedded in those impoverished stimuli and which of these factors are essential in visual processing of biological motion. Earlier studies suggest that orientation is a crucial factor in biological motion processing. The short-term priming experiment presented in this paper will further investigate the legitimacy of the primacy of orientation and suggest different solutions based on contradicting findings in previously published studies.

In a serial two-choice reaction-time task, participants were presented with a patch-light display of a human engaged in one of three possible actions: climbing up a rope, jumping jacks, and walking. Participants had to identify the in-plane orientation of the human figure emerging from the moving patch-lights. Reliable facilitation effect was established for transitions containing same-oriented upright trails and same-oriented inverted trials. Interestingly, transitions of same-oriented upright trials produced significantly greater facilitation effect than transitions of same-oriented inverted trials.

We live in daily cycles of brightness and darkness throughout our lives. Light is a device, both through natural and artificial sources, that supports the working of our brains in the processing, reconstruction, and classification of information (Galetta, 2014). According to the models of mental processing provided by various individuals in literature, light as a stimulus can induce specific emotions and behaviors in people (Tomassoni et al., 2015). The objective of this thesis project is to study the possibility of using light patterns and motions to support stress reduction and provide people with a feeling of calm in an indoor setting, where access to nature is limited. The participants (n=30) of the study are students and working adults who live in different cities. They have been asked to evaluate the natural elements and what they perceive as calmness and relaxation through the projection of five different sets of skies. The study considers light as a Biophilic design element, which provides people with calm and a sense of well-being in their work environment (i.e., home office, working space). Through the results of this first survey and insight from the study, the author conducted a lighting experiment using a small model and surveyed the participants’ responses on mood and preference to the different lighting conditions in the model. Consequently, it turned out that most of the participants, from both the online survey and through direct physical interaction with the model, mentioned that they would prefer spending their breaks during their workday in a space that has both patterned light and moving light (not static), rather than the absence of light patterns and motion.  By shaping human experience, the study investigates the possibility of using artificial light as a Biophilic design element to provide people with a feeling of calm and, therefore, to support stress reduction in their work environment.

This thesis examines contemporary literary and cinematic representations of Paris in relation to the dynamics of collective memory, arguing that the city emerges as a privileged site in which to explore critical questions of identity, memory and citizenship in France. In this comparative approach to representations of memories of the Holocaust and the Algerian War in France, I identify a shared lexicon of urban space simultaneously hiding and revealing traces of the past in the contemporary city. This study of memories and their urban and palimpsestic representations challenges the tendency to separate the disciplines of postcolonial and post-Holocaust studies, and in so doing contests the conceptual separation of metropolitan, European and colonial histories. As such, it contributes to a growing interdisciplinary field of French and Francophone studies that extends the object of study beyond the purely metropolitan. I draw on and engage with theoretical work in the fields of memory studies, postcolonial studies and post-Holocaust studies to consider how urban space opens up a legitimate new way of engaging with the overlaps and intersections between different memories without undermining the crucial element of difference. Underpinned by poststructuralist concerns, memory emerges here as an inherently constructed concept.

Accepting that one of the main duties of an architect is mastering the tectonic expression of the building and its architectural effect, could there be a mechanism that allows a building or object to change its expression? Could the envelope of a building respond to its exterior context or internal function by changing its appearance? How can the elements of a building screen - whether in wall or roof - change their orientation and configuration to express a response to environments inside or outside? We know that the modern ideas of "wall-free structure" and "transparency" have begun to change the concept of building envelopes. These changes have allowed envelopes to become lighter, less opaque, and more flexible; and as a result the architect has more freedom in exterior expression. In the Seagram Tower, for instance, while I-beams emphasize the vertical effect of the tower, the glass envelope allows the building to change its surface effect from day to night. Having more freedom in the exterior expression of buildings has not only brought transparency but also opened a door for a greater interaction between inside and outside. If, in the past, the exterior walls of a building, limited by structural needs, had to carry its weight, today, analogous with living nature, the use of a structural skeleton gives much more freedom of expression and interaction to the exterior envelope of the buildings. Rooted in the ground and running through the building's mass, instead of outside it, the skeleton takes on the load of the building, and masonry walls can be replaced with partitioning envelopes that are open to freer interpretation. Influenced by engineers and architects like Chuck Hoberman and Santiago Calatrava, my areas of study since 1997 have been focused on the subject of movement in structures and kinetic architectural elements. I have approached this subject from two points of view. While my first study models explored the ways structures can be folded and transformed, this book is about the investigation and study of envelopes and tectonic planes that can be manipulated through operable mechanisms to change their interior or exterior expression. This study is based on the separation between the mechanisms which are the cause of the movements in the models and the kinetic planes in envelopes that have the duty of interaction between inside and outside. If folding of structures in the early stages of my studies resulted in "metamorphosis", my current work is about studying mechanisms that change the surface of an envelope and result in "transmutation".
Master of Architecture

Functional near-infrared spectroscopy (fNIRS) and diffuse optical tomography (DOT) are non-invasive techniques used to infer stimulus-locked variations in human cortical activity from optical variations of near-infrared light injected and subsequently detected at specified scalp locations. Relative to functional magnetic resonance imaging (fMRI) and electroencephalography (EEG), these optical techniques are more portable, less invasive and less sensitive to motion artifacts, making them ideal to explore brain activity in a variety of cognitive situations, and in a range of populations, including newborns and children. FNIRS and DOT measure stimulus-locked hemodynamic response in the form of changes in oxy- (HbO) and deoxy- (HbR) hemoglobin concentration taking place in specific areas. This signal is however structurally intertwined with physiological noise owing to cardiac pulsations, respiratory oscillations and vasopressure wave. Furthermore, the absolute magnitude of hemodynamic responses is substantially smaller than these non-informative components of the measured optical signal, and has a frequency which largely overlaps with that of the vasopressure wave. Thus, recovering the hemodynamic response is a challenging task. Several methods have been proposed in the literature to try to reduce physiological noise oscillations and recover the hemodynamic response, but none of them has become a common standard in the optical signal processing pipeline. In this thesis, a novel algorithm, devised to overcome a large subset of drawbacks associated with the use of these literature techniques, is presented and validated. Reduced sensitivity to motion artifacts notwithstanding, the optical signal must always be assumed as contaminated by some form of mechanical instability, most prominently during signal acquisitions from pathological (e.g., stroke patients) or difficult (e.g., newborns) populations. Several techniques have been proposed to correct for motion artifacts with the specific aim of preserving contaminated measures as opposed to rejecting them. However, none of them has become the gold standard in the optical signal processing pipeline, and there are currently no objective approaches to choose the most appropriate filtering technique based on objective parameters. In fact, due to the extreme variability in shape, frequency content and amplitude of the motion artifacts, it is likely that the best technique to apply is data-dependent and, in this vein, it is essential to provide users with objective tools able to select the best motion correction technique for the data set under examination. In this thesis, a novel objective approach to perform this selection is proposed and validated on a data-set containing a very challenging type of motion artifacts. While fNIRS allows only spectroscopic measurements of hemoglobin concentration changes, DOT allows to obtain 3D reconstructed images of HbO and HbR concentration changes. To increase the accuracy and interpretability of DOT reconstructed images, valuable anatomical information should be provided. While several adult head models have been proposed and validated in this context, only few single-ages head models have been presented for the neonatal population. However, due to the rapid growth and maturation of the infant's brain, single-age models fail to capture precise information about the correct anatomy of every infant's head under examination. In this thesis, a novel 4D head model, ranging from the preterm to the term age, is proposed, allowing developmental neuroscientists to make finer-grained choices about the age-matched head model and perform image reconstruction with an anatomy as similar as possible to the real one. The outline of the thesis will be as follows. In the first two chapters of this thesis, the state of the art of optical techniques will be reviewed. Particularly, in chapter 1, a brief introduction on the physical principles of optical techniques and a comparison with other more common neuroimaging techniques will be presented. In chapter 2, the components of the measured optical signal will be described and a brief review of state of the art of the algorithms that perform physiological noise removal will be presented. The theory on which optical image reconstruction is based will be reviewed afterwards. In the final part of the chapter, some of the studies and achievements of optical techniques in the adult and infants populations will be reviewed and the open issues and aims of the thesis will be presented. In chapters 3, 4 and 5, new methodologies and tools for signal processing and image reconstruction will be presented. Particularly, in chapter 3, a novel algorithm to reduce physiological noise contamination and recover the hemodynamic response will be introduced. The proposed methodology will be validated against two literature methods and results and consequent discussion will be reported. In chapter 4, instead, a novel objective approach for the selection of the best motion correction technique will be proposed. The main literature algorithms for motion correction will be reviewed and the proposed approach will be validated using these motion correction techniques on real cognitive data. In chapter 5, instead, a novel 4D neonatal optical head model will be presented. All the steps performed for its creation will be explained and discussed and a demonstration of the head model in use will also be exhibited. The last part of the thesis (chapters 6, 7 and 8) will be dedicated to illustrate three distinct examples of application of the proposed methodologies and tools on neural empirical data. In chapter 6, the physiological noise removal algorithm proposed in chapter 3 will be applied to recover subtle temporal differences between hemodynamic responses measured in two different areas of the motor cortex in short- vs. long- duration tapping. In chapter 7, the same algorithm will be applied to reduce physiological noise and recover hemodynamic responses measured during a visual short-term memory paradigm. In both chapters, cognitive results and a brief discussion will be reported. In chapter 8, instead, the neonatal optical head model proposed in chapter 5 will be applied to perform image reconstruction with data acquired on a healthy full term baby. In the same chapter, the importance of motion artifact correction will be highlighted, reconstructing HbO concentration changes images before and after the correction took place.
La spettroscopia funzionale nel vicino infrarosso (fNIRS) e la tomografia ottica diffusa (DOT) sono tecniche non invasive che, sfruttando le proprietà della luce nel vicino infrarosso, permettono di misurare l'attività cerebrale. Sorgente e detettore sono posti a contatto con il cuoio capelluto ad una distanza prestabilita. Dall'attenuazione subita dalla luce nel passaggio attraverso i tessuti cerebrali, è possibile ricavare le variazioni nell'attività corticale, che avvengono in seguito alla presentazione di uno stimolo. Rispetto alla risonanza magnetica funzionale (fMRI) ed all'elettroencefalografia (EEG), le tecniche ottiche sono più portatili, meno invasive e meno sensibili agli artefatti da movimento; sono pertanto tecniche ideali per esplorare l'attività cerebrale in numerosi ambiti cognitivi e in un gran numero di popolazioni, come neonati e bambini. FNIRS e DOT misurano la risposta emodinamica in seguito alla presentazione di uno stimolo nella forma di variazioni nella concentrazione di emoglobina ossigenata (HbO) e deossigenata (HbR) che avvengono in specifiche aree della corteccia. Tuttavia, il segnale misurato non contiene solo la risposta emodinamica d'interesse, ma anche rumore fisiologico, dovuto per esempio alla pulsazione cardiaca, alle oscillazioni dovute alla respirazione e all'onda vasomotrice. Inoltre, la risposta emodinamica d'interesse si presenta di solito con un'ampiezza ridotta rispetto alle componenti non informative del rumore fisiologico e con una frequenza molto simile a quella dell'onda vasomotrice. Da ciò si deduce come stimare la risposta emodinamica sia un compito molto difficile. Molti metodi sono stati proposti in letteratura per cercare di ridurre il rumore fisiologico e stimare la risposta emodinamica. Tuttavia, ad oggi, non esiste un metodo standard per l'analisi del segnale ottico. In questa tesi, quindi, è stato proposto e validato un nuovo algoritmo, messo a punto per far fronte agli svantaggi associati ai metodi presenti in letteratura. Nonostante la ridotta sensibilità agli artefatti da movimento, il segnale ottico ne risulta comunque contaminato, soprattutto durante acquisizioni di popolazioni patologiche (per esempio pazienti diagnosticati con ictus) o difficili (come per esempio i neonati). Sono state proposte numerose tecniche per correggere gli artefatti da movimento, invece di eliminare la parte di segnale da essi contaminata. Tuttavia, nessuna di queste tecniche, per il momento, è riuscita a emergere come la più adatta per l'analisi del segnale ottico. In aggiunta a questo, non esistono criteri oggettivi con cui sia possibile selezionare la tecnica migliore da applicare, dato un segnale misurato. Si suppone, infatti, che, data l'estrema variabilità presente negli artefatti da movimento in termini di forma, contenuto in frequenza e ampiezza, la tecnica da applicare sia dipendente dal segnale misurato nello specifico caso. Da ciò emerge la necessità di fornire agli sperimentatori dei criteri oggettivi, che permettano loro di selezionare la tecnica di correzione più adatta ad ogni segnale misurato. In questa tesi, quindi, è stato proposto un innovativo ed oggettivo approccio per la selezione della tecnica di correzione da utilizzare. La validazione è stata eseguita su dei segnali contenenti una tipologia di artefatto da movimento molto difficile da identificare e correggere. FNIRS permette di ottenere solo misure spettroscopiche delle variazioni di concentrazione di emoglobina; DOT invece è in grado di ricostruire immagini tridimensionali delle variazioni di concentrazione di HbO e HbR. Per aumentare l'accuratezza e l'interpretabilità delle immagini ricostruite con DOT, è necessario fornire accurate informazioni anatomiche di supporto. Numerosi modelli di teste per tecniche ottiche sono stati proposti e validati nella popolazione adulta. Al contrario, in quella neonatale, i modelli analoghi creati finora sono molto pochi e tutti riferiti ad una sola età neonatale. Tuttavia, nei neonati, il cervello è soggetto ad una crescita ed una maturazione molto rapida. Per questo motivo, modelli riferiti ad una singola età neonatale falliscono nel fornire informazioni anatomiche corrette per ogni neonato sotto esame. In questa tesi si è proposto un innovativo modello 4D di teste per tecniche ottiche, contenente informazioni anatomiche per neonati pretermine e a termine. Questo modello può fornire ai neuroscienziati che lavorano in ambito evolutivo la possibilità di selezionare il modello corrispondente all'età del neonato in esame e ricostruire quindi le immagini di variazione di concentrazione di emoglobina usando un'anatomia il più possibile vicina a quella reale. L'organizzazione della tesi è la seguente. Nei primi capitoli verrà analizzato lo stato dell'arte delle tecniche ottiche. In particolare nel capitolo 1 verrà presentata una breve introduzione dei principi fisici alla base di queste tecniche alla quale seguirà un confronto con le tecniche di neuroimmagini più diffuse. Il capitolo 2 descriverà le componenti del segnale ottico misurato e verrà illustrato lo stato dell'arte relativo ad algoritmi di rimozione del rumore fisiologico. Successivamente sarà esposta la teoria che sta alla base del processo di ricostruzione delle immagini. Nella parte finale del capitolo, invece, verranno presentati alcuni studi che hanno utilizzato tecniche ottiche sia nella popolazione adulta che in età evolutiva. Infine saranno presentati gli scopi di questa tesi. I capitoli 3, 4 e 5 saranno dedicati alla presentazione di nuovi strumenti e metodologie per l'analisi del segnale ottico e per la ricostruzione di immagini ottiche. In particolare nel capitolo 3 verrà introdotto un nuovo algoritmo per la rimozione del rumore fisiologico e la stima della risposta emodinamica. La metodologia proposta verrà validata tramite il confronto con due algoritmi preesistenti. Il capitolo 4 tratterà il problema degli artefatti da movimento e proporrà un innovativo e oggettivo approccio per la selezione della tecnica di correzione da utilizzare. Le principali tecniche di correzione verranno illustrate e il nuovo approccio verrà validato utilizzando dati cognitivi reali. Nel capitolo 5 verrà presentato un nuovo atlante 4D neonatale di modelli di teste per tecniche ottiche. Verranno descritti tutti i passaggi che hanno portato allo sviluppo di questo atlante e ne sarà riportato un esempio applicativo. La parte finale di questa tesi (capitoli 6, 7 e 8) presenterà tre distinti esempi applicativi, su dati neurali empirici, delle metodologie e strumenti proposti. L'algoritmo per la rimozione del rumore fisiologico proposto nel capitolo 3 sarà utilizzato nel capitolo 6 per stimare differenze temporali poco evidenti tra risposte emodinamiche, misurate in due diverse aree della corteccia durante compiti di movimento manuale di diversa durata. Nel capitolo 7 lo stesso algoritmo verrà applicato a dati acquisiti durante un paradigma di memoria visiva a breve termine. Infine nel capitolo 8 verranno ricostruite immagini di variazioni di concentrazione di emoglobina, utilizzando il modello di teste per tecniche ottiche presentato nel capitolo 5. I dati sono stati acquisiti da un neonato a termine e il modello di testa utilizzato nella ricostruzione è quello relativo all'età corrispondente. Nello stesso capitolo verranno ricostruite immagini di concentrazione sia in presenza che in assenza di tecniche di correzione di artefatti da movimento, evidenziandone così l'importanza.

Being able to generate predictions about what is going to happen next while observing other people’s actions plays a crucial role in our daily lives. Different theoretical explanations for the underlying processes of humans’ action prediction abilities have been suggested. Whereas an embodied account posits that predictive gaze relies on embodied simulations in the observer’s motor system, other accounts do not assume a causal role of the motor system for action prediction. The general aim of this thesis was to augment current knowledge about the functional mechanisms behind humans’ action prediction abilities. In particular, the present thesis outlines and tests an embodied account of action prediction. The second aim of this thesis was to extend prior action prediction studies by exploring infants’ online gaze during observation of social interactions. The thesis reports 3 eye-tracking studies that were designed to measure adults’ and infants’ predictive eye movements during observation of different manual and social actions. The first two studies used point-light displays of manual reaching actions as stimuli to isolate human motion information. Additionally, Study II used transcranial magnetic stimulation (TMS) to directly modify motor cortex activity. Study I showed that kinematic information from biological motion can be used to anticipate the goal of other people’s point-light actions and that the presence of biological motion is sufficient for anticipation to occur. Study II demonstrated that TMS-induced temporary lesions in the primary motor cortex selectively affected observers’ gaze latencies. Study III examined 12-month-olds’ online gaze during observation of a give-and-take interaction between two individuals. The third study showed that already at one year of age infants shift their gaze from a passing hand to a receiving hand faster when the receiving hand forms a give-me gesture compared to an inverted hand shape. The reported results from this thesis make two major contributions. First, Studies I and II provide evidence for an embodied account of action prediction by demonstrating a direct connection between anticipatory eye movements and motor cortex activity. These findings support the interpretation that predictive eye movements are driven by a recruitment of the observer’s own motor system. Second, Study III implicates that properties of social action goals influence infants’ online gaze during action observation. It further suggests that at one year of age infants begin to show sensitivity to social goals within the context of give-and-take interactions while observing from a third-party perspective.

The miniaturization of projection technology has enabled a new class of lightweight mobile devices with embedded projectors. Projection engines as small as a postage stamp are currently being embedded in thousands of mobile devices. Mobile projector-based devices differ in very fundamental ways from the display-based devices we commonly use. Mobile projectors can be carried with the user and project imagery into almost any space, projected content is visible to multiple users and supports social interaction, physical objects and surfaces can be augmented with projected content, and embedded projectors can enable new form-factors for mobile displays. This research investigates the potential of mobile projectors as a new platform for human-computer interaction. I aim to demonstrate that the unique affordances created by the miniaturization of projection technology can inspire new and compelling interaction with single-users, multi-users, the environment, and projector-embedded objects. This research presents a comprehensive survey of mobile projector-based interaction – documenting interaction with historic projection devices; introducing novel interaction techniques, metaphors, and principles for mobile projector-based systems; providing implementation details of functional prototype devices using mobile projectors; presenting technical innovations, such as the development of specialized projectors and custom marker tracking algorithms; and detailing results from preliminary user testing with the prototype systems created. This research forms a systematic investigation of the past, the present, and a possible future for interaction using mobile projectors.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
Includes bibliographical references (p. 173-182).
by Charles Quentin Davis.
Ph.D.

This study evaluated the effects of public postings on energy conservation behavior at a public university, using a multiple baseline design across three settings; bathrooms break rooms, and conference rooms. The behavior of building occupants was recorded to assess the frequency at which those individuals would turn lights off upon exiting an unoccupied room. The independent variables implemented by experimenters (light-switch plate stickers and laminated signs) had little to no effects on cumulative instances of lights turned off however, the installation of motion sensor lights produced better results. Across all conditions, lights were turned off most frequently in conference rooms (65% of observations) followed by break rooms (9% of observations), and bathrooms (3% of observations).

VYSOKÉ UČENÍ TECHNICKÉ V BRNĚ Distributed Ray Tracing, also called distribution ray tracing and stochastic ray tracing, is a refinement of ray tracing that allows for the rendering of "soft" phenomena, area light, depth of field and motion blur.

Les véhicules de demain, (2020), devront diminuer leurs émissions globales de CO2 de 30% selon les directives européennes. Une solution qui apparait aujourd’hui comme inévitable est la substitution des métaux présents dans les châssis de véhicules par des matériaux composites plus légers et tout aussi performants. Pour généraliser cette approche à tout le secteur automobile, un temps court de fabrication des pièces est exigé pour satisfaire les cadences de production allant jusqu’à 1000 véhicules par jour. La production automatisée et robotisée de ces matériaux, basée sur la technologie de photo-polymérisation au moyen de rayonnements UV, répond à ces exigences. Le procédé de fabrication élaboré se décompose en deux phases : une phase de fabrication automatisée de pré-imprégnés (prépregs), produits semi-finis, et une phase de mise en forme et d’obtention du produit final (composite UV). La première étape consiste en l’imprégnation d’un renfort fibreux sec par une résine liquide photo-polymérisable, puis l’irradiation de celle-ci par des rayonnements UV, de manière à ce que la résine ne soit pas totalement polymérisée. On obtient alors un prépreg collant. La seconde étape de fabrication impose que les pré-imprégnés soient conditionnés parfaitement sous forme de bobines pour qu’ils soient intégrés dans un dispositif robotisé de dépose. D’où la nécessité de concevoir et de réaliser une machine automatisée de production des pré-imprégnés (objet de cette thèse). Cette machine a nécessité une automatisation se caractérisant par l'utilisation d'outils d'instrumentation et de pilotage modernes (servomoteurs Brushless, IHM, capteurs, …). Les essais réalisés sur cette machine ont permis de réaliser des premiers prépregs, dont les résultats ont conduit à des pistes de réflexion pour approfondir l'automatisation de la machine en vue d'améliorer le procédé de fabrication de ces prépregs
The overall CO2 emission of the future vehicles, (2020), must be reduced by 30%, according to European directives. A solution that seems inevitable nowadays is the substitution of metals present in the vehicle chassis by lighter and equally efficient composite-materials. To generalize this approach throughout the automotive sector, a short manufacturing time of these materials is required to meet the high required production rates, of up to 1000 vehicles per day. The automated and robotic production of these materials, depending on the photo polymerization technology by UV radiation, meets these requirements. The developed automated manufacturing process consists of two phases: the phase of automated manufacturing of semi-finished composite (prepreg), and the phase of shaping and obtaining the final composite (UV composite). The first phase depends on the impregnation of fibrous reinforcement with a photo-polymerizable and liquid resin, then, on the partial irradiation of impregnated reinforcement with UV rays, in such a way that the resin is not completely cured. Thereby, a tacky prepreg is obtained. The second phase of automated manufacturing process requires that the prepregs must be perfectly reeled up in a form of coils, so that they can be incorporated in a robotic lay-up placement head. Hence, the need to design and produce a machine of automated prepreg production (subject of this thesis) is absolutely necessary. This machine requires automation, characterized by the use of modern instrumentations and control tools (Brushless Servo, Human–computer interface HCI, sensors...). The tests performed by this machine have enabled the production of the first prepregs, of which the results led to further approaches to develop the automation of this machine in order to improve the prepregs manufacturing process

Cette thèse consiste à étudier le motif de la lumière dans l’œuvre poétique de Verlaine. La notion de motif dans la perspective thématique que nous avons adoptée et qui est définie principalement par Jean-Pierre Richard dans L’univers imaginaire de Mallarmé et dans Microlectures s’étend à un ensemble de termes qui, de par leur sens et leur référence, entretiennent entre eux des rapports variés et assurent à une œuvre sa cohésion. Ces termes, tout en renvoyant à une même notion, en l’occurrence la lumière, se métamorphosent au fil du texte et apparaissent sous des formes variées. Nous nous sommes fixés pour objectif de les repérer et d’étudier leur variation et leurs fonctions. Le poète adopte face à la réalité une attitude négative se caractérisant par le repliement sur soi et l’abandon. L’espace chez lui qu’il soit ouvert ou fermé est oppressant et le temps, associé souvent au passé, est synonyme de perte et de déception. De nombreux poèmes, surtout au début de l’œuvre, reflètent cette impression d’inertie et de défaillance. Mais malgré la forte présence lyrique, l’expression toujours suggestive ne se laisse pas dominer par le discours. A cette négativité, le poète associe la noirceur. Toutes les lumières dans ces poèmes sont sombres ou faibles. Les occurrences qui relèvent de cette tonalité sont de loin les plus nombreuses. Leur mise en œuvre et leur fréquence témoigne de l’importance que Verlaine accorde à l’esthétique. Mais le lyrisme de Verlaine est aussi celui de la célébration. La plus grande partie de son œuvre est composée de portraits et d’autoportraits. Dans cet ensemble où sont célébrés Dieu, les héros, les femmes, etc. Verlaine choisit l’envers de la discrétion. Il emploie des procédés qui favorisent l’exagération. Les portraits idéalisés sont sa manière de manifester sa quête d’altérité. L’expression exagérée caractéristique de ces poèmes engage des lumières fortes, lumineuses, blanches…Mais dans un certain nombre de poèmes, Verlaine rompt entièrement avec tout héritage poétique et a écrit une poésie qui tente de saisir la réalité dans sa fuite et dans sa métamorphose. Il adopte une voie intermédiaire qui soumet le langage aux exigences de l’artiste. Certaines lumières elles-mêmes changeantes et indéterminées peuvent en effet répondre à ce besoin. Ce besoin d’interroger le langage est en réalité commun aux poètes de la deuxième moitié du XIXème siècle. L’époque se caractérise par une évolution des goûts et des idées, mais aussi par un sentiment d’inquiétude face à la modernité naissante. Cette évolution et ce malaise sont perceptibles chez Verlaine. Celui-ci atteste de sa modernité en plaçant son art sur la frontière de ce qui est dit et de ce qui est tout simplement suggéré. L’existence de cet art dépend en fait de la complicité qui s’instaure par-delà les mots entre le poète et le lecteur. Si Verlaine semble gagner le pari d’une réception large, c’est grâce à cette poétique de l’indétermination et de la suggestion
This thesis consists in studying the motif of the light in the poetry of Verlaine. The concept of motif in the thematic approach we have adopted and which is defined principally by Jean-Pierre Richard in L’univers imaginaire de Mallarmé and in Microlectures extends to a set of terms which, by their sense and reference, have various connections between them and ensure the work cohesion. These terms, while referring to a same notion, in this case the light, are transformed in the text and appear under various forms. We have set as a target to identify them and to study their changes and their functions.In the face of the reality, the poet adopts a negative attitude characterized by self-absorption and abandonment. The space that is open or closed is oppressive and the time, often associated with the past, means loss and disappointment. Many poems, especially at the beginning of the work, reflect this sense of inertia and failure. But despite the strong lyrical presence, the constantly suggestive expression cannot be dominated by the speech. The poet combines the dark with this abandonment. All the lights in these poems are dark and low. Occurrences that are related to this tone are by far the most numerous. Their use and their frequency reflect the importance that Verlaine attaches to the forms.But the lyricism of Verlaine is also the lyricism of celebration. The major part of his work is composed of portraits and self-portraits. In this set where God, heroes, women… are celebrated, Verlaine chooses the explicit expression. He uses processes that support the exaggeration. The idealized portraits are his way of showing his quest for otherness. The expression in these poems involves bright, shining and white lights.But in some poems, Verlaine breaks completely with poetic legacy and wrote a poetry that attempts to grasp the reality in its movement and its metamorphosis. He adopts a middle way that meets the needs of the artist. Some lights, themselves unstable and indeterminate, can meet this need. The need of asking language is in fact common to the poets of the second half of the nineteenth century. The era is characterized by changing tastes and ideas, but also by a concern about the emerging modernity. This development and this discomfort can be perceived in the poetry of Verlaine. The Verlaine modernity appears between what is said and what is just suggested.In fact, the existence of this art depends on the complicity that exists beyond the words between the poet and the reader. Verlaine seems to meet the challenge of a large reception thanks to the poetics of indeterminacy and suggestion

Prior scholarship has established that Pauline modifications of the conventional Koine epistolary prescript contribute to Paul’s self-positioning with his recipients and the persuasive force of his letters. This study furthers an understanding of Paul’s epistolary practice by exploring contributions of the remembrance motif (an expression of assurance that the sender remembers the letter’s recipients) and the distinctive Pauline litotic form of the disclosure formula (οὐ θέλω ὑμᾶς ἀγνοεῖν, variously translated in English versions as “I do not want you to be uninformed, unaware, ignorant”) to Paul’s communicative strategy in light of documentary papyri. The study undertakes synthesised sociolinguistic and semantic analyses of μνεία, ἀδιαλείπτως, and the litotic disclosure formula in documentary papyri. Applying Michael Halliday’s Systemic Functional Linguistics Theory of Register to documentary papyri demonstrates that μνεία, ἀδιαλείπτως, and the litotic disclosure formula belong to a formal register. Documentary papyri indicate that μνεία carries a nuance of remembrance with responsive action (i.e., prayer) in the remembrance motif rather than the sense “mention” provided by major lexica. Documentary papyri also indicate that ἀδιαλείπτως is polysemous. Eighty per cent of papyrological attestations of ἀδιαλείπτως occur in legal documents where the lexeme reinforces the certainty of a promisor’s commitment to terms of a contract: “without fail” captures the illocutionary force of this sense that is additional to the customarily understood frequentative sense typically rendered “constantly.” Letter writers used the remembrance motif to establish or maintain friendly relations with their recipients (philophronesis). The study argues that letter writers used the litotic disclosure formula similarly. Epistolary papyri facilitate the identification of baselines for the wording of the formulae and indicate that the Pauline forms depart from them. Using an interpretive lens of the Theory of Norms and Exploitations (developed by the lexicographer Patrick Hanks), the study shows how polite, formal language in epistolary formulae further contributed to philophronesis. Paul’s use of unexpected, polite, formal language in the remembrance motif and litotic disclosure formula suggests the carefully crafted modification of the formulae to intensify their philophronetic function and persuasive force. Nuances of μνεία and ἀδιαλείπτως complement the modified remembrance motif’s emphatic philophronesis. “I remember you without fail in my prayers” evokes the sociotheological significance of remembrance and functions as an emphatic reassurance of Paul’s pastoral concern for his recipients. The distinctive Pauline form of the litotic disclosure formula contributes to Paul’s communicative strategy by anchoring the presentation of subsequent information in the positive relationship that exists or that Paul wants to exist between himself and his recipients. The new elements of communicative strategy revealed by the register and semantic analyses of this study inform exegesis of the NT and demonstrate promise for research into the language of the NT and beyond into later antiquity.

Notre étude répond a l'intitulé « La Dialectique ombre et lumière dans la poésie de Baudelaire et Senghor ». Elle s'attache à décrire la sémantique de ces deux métaphores de la condition humaine dans les œuvres de nos auteurs, sous l'autorité méthodologique de la stylistique de Spitzer et de la thématique richardienne. De fait, bien plus qu'un simple ornement, ombre et lumière traduisent au mieux leur pensée et décrivent la structure des œuvres. Ainsi, sont-elles une matrice génératrice d'une esthétique, d'une philosophie, et d'une religion parfois dissonante. Opportunément, le travail tente de mettre en lumière l'apport de Baudelaire dans la poésie senghorienne. Il établit que, contrairement à ce que certains critiques ont écrit, et à ce que Senghor à laisser entendre, sa poésie n'est pas influencée par celle du poète français. Ce dernier agit plutôt comme un révélateur, en lui faisant prendre conscience de la beauté de l'Afrique et de la femme noire, leur véritable point de rencontre
Our study answers to the title "The Dialectic shadow and light in Baudelaire and Senghor poetry". It strives to describe semantics of these two metaphors of the human condition in the work of our authors, under the methodological authority from Spitzer stylistics and from Richardřs themathic. Ac-tually, more than a simple ornament, a shadow and a light translate at best as possible their thought and describe the structure of the work. So, they are a generative matrix of aesthetics, a philosophy, and a sometimes dissonant religion. Conveniently, the work tries to highlight Baudelaire contribution in the Senghor poetry. It establishes that, in opposition to what some critics wrote, and in what Senghor let understand, his poetry is not influenced by that of the French poet. This last one acts rather as a revelation, by making him become aware of the beauty of Africa and black woman, their real meeting point

La notion d’espace prend un sens très fort et comme actif dans le travail artistique de Robert Irwin. Celui-ci instaure un nouveau mode d’être pour l’espace par son installation dite « site-conditioned/determined » tout en la nouant pourtant avec celui du site préexistant, qu’il soit intérieur ou extérieur. Le statut ontologique de son installation est celui d’un « non-objet », d’une extrême simplicité de forme et d’un minimum de matérialité : une bande noire ou une surface de voile semi-transparent, à la fois objet montré et sujet montrant, mettent en jeu lumière et ombre, attirant notre attention non seulement sur lui mais tout autour, intégrant l’espace où il s’intègre. L’installation est mise en œuvre de son environnement architectural ou naturel. L’installation est ainsi installa(tten)tion, c’est-à-dire installation qui installe l’attention. Ce que procure l’artiste au spectateur par son installation est la sensation pure de l’apparaître dynamique et changeant de l’espace du monde réel. Sensible d’abord à la dimension réelle de l’espace physique, nous découvrons peu à peu sa dimension virtuelle, puis transcendantale, au fur et à mesure que ce processus de sensation pure déclenché par l’aspect inhabituel de cet espace pourtant réel se déploie. Grâce au toucher direct et vivant d’un sentir aiguisé, et visuel et kinesthésique, éveillé par l’installation de Robert Irwin, devient quasi palpable notre conscience d’exister. Elle résonne alors à la réalité directe et immédiate du monde mais aussi aux virtualités de son apparaître et à ce qui les rend possibles : sa forme en soi, révélée et actualisée comme la véritable nature de l’espace réel
The notion of space has a strong and active meaning in Robert Irwin’s art work. He establishes a new way of appearance of space through his so-called “Site-conditioned/determined” installation by uniting the installation with the space of the existing site, whether indoors or out. The ontological status of his installation is that of a “none-object”: extremely simple in form and with a minimum of materials. He uses a black tape or a surface of semitransparent scrim. These objects are both “object shown” and “subject showing”. They play with light and shadow, catching our attention not only on themselves but also on their surroundings, including the space into which they fit. So the art piece is not only the installation itself but its circumstance with its whole architectural or natural environment. So the installation is installa(tten)tion, that is to say an installation that installs attention. Through the installation, the artist provides for the viewer a chance to have a pure sensation of the dynamic and changing appearance of space in the real world. At first sensitive to the real dimension of physical space, we discover little by little its virtual and then transcendental dimensions, as this process of pure sensation unfolds, triggered by the unusual aspect of the real space caused by the installation. A direct and living contact through a sharpened feeling, both visual and kinesthetic, with the space, awakened by the installation of Robert Irwin, makes our awareness of existing almost palpable. This awareness of existing resonates with the direct and immediate reality of the world as well as potentialities of the world’s appearance and what makes these potentialities possible: form in itself, revealed and actualized as the true nature of real space

Antipode de la lumière, le noir est pourtant indissociable du cinéma. Qu'est-ce que le noir du cinéma ? Figure de l'ombre ou de l'obscurité à l'image, il y est aussi présent en tant que tel, un noir sans représentation et avec sa réalité physique singulière. Ce noir-là est avant tout une condition technique, que l'on cache, mais qui joue un rôle décisif dans la production des illusions d'optique et la création de la fiction. Il est également omniprésent dans tout le processus de fabrication de l'image cinématographique. Le noir joue avec la lumière, conditionne la visibilité et l'invisibilité et, en ce sens, invente le cinéma. Le noir propose une autre manière de comprendre ce qu'est le cinéma ainsi que son fonctionnement. Cette étude traitera d'abord l'aspect matériel de l'image argentique : le noircissement photochimique et les idées qu'il suggère en tant que processus de la formation et de la dissolution de l'image. On évoquera ensuite, au travers du noir formel, outil rhétorique et mécanique, les effets produits par le noir, lorsqu'il intervient en tant que forme dans l'image, de l'image, et entre les images. Enfin, en tant que dispositif envahisseur de l'écran et de l'espace de projection, le noir révèlera son rôle dans le dispositif du spectacle visuel : la construction d'un accès à l'illusion et à la révélation. Chaque partie se déploiera dans un parcours à la fois historique, technique, et esthétique. On verra notamment dans des tentatives artistiques et expérimentales que la mise en avant du noir permet de révéler les caractéristiques du médium cinématographique, voire de ré-inventer le cinéma. Cette quête du noir se révèle comme une quête sur la nature du cinéma, nature que l'industrie du cinéma tente d'effacer. Le noir fait voir, et il fait voir autrement
Even though black is the antipode of light it is nevertheless inseparable from the world of cinema. What is black in cinema? A figure of shadow or darkness in the image that is also present as such. Black without representation and with its singular physical reality. This blackness is above all a technical condition which is hidden but which plays a decisive role in the production of optical illusions and the creation of fiction. It is also omnipresent in the entire process of making the cinematographic image. Black plays with light and conditions visibility and invisibility. In this sense it invents cinema. Black also offers another way of understanding what cinema is and how it works. This study will first deal with the material aspect of photography: photochemical blackening and the ideas it suggests as a process of image formation and dissolution. I will then portray the different effects produced by black- the black shape a rhetorical and mechanical tool. When it intervenes as a form in the image, of the image, and between the image. Finally, I will discuss how black can be an invading device of the screen and the projection space and reveal its role as a visual spectacle apparatus: the construction of an access to illusion and revelation. Each part of this outline will be dealt with in a historical, technical and aesthetic way. We will see in particular in artistic and experimental attempts that the emphasis on black makes it possible to reveal the characteristics of the cinematographic medium or even to re-invent cinema. This quest for blackness is revealed as a quest for the nature of cinema. A nature that the film industry is trying to erase. Black makes you see but it makes you see differently