Die Nutzbarmachung des in den Köpfen von Mitarbeitern und Kunden schlummernden, disruptiven Ideenpotenzials stellt Unternehmen weiterhin vor eine große Herausforderung. Der Ansatz des Idea Mirrors verfolgt in diesem Zusammenhang das Ziel, die Möglichkeiten großer Wandbildschirme zu nutzen, um das kreative Ideenpotenzial von Unternehmen insbesondere in den frühen Phasen des Innovationsprozesses besser sichtbar zu machen und so die Motivation zur Ideengenerierung, zur kommunikativen Ideenvernetzung und zur späteren gemeinschaftlichen Ideennutzung zu fördern. Die Einbettung der Benutzungsschnittstelle in den normalen Geschäftsalltag an halböffentlichen Orten wie Empfangshallen, Cafeterien oder in Gruppenräumen soll die Hemmschwelle zur Interaktion herabsetzen und gleichzeitig die Wahrnehmung der dargestellten Inhalte durch eine breite Nutzerbasis garantieren.

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La prochaine décennie instrumentale en astronomie se veut extrême. Elle s’ouvre avec l'arrivée des ELTs (Extremely Large Telescopes). Leur miroir primaire géant permettra d'augmenter considérablement la quantité de flux collectée et d'améliorer la résolution angulaire, paramètres clés pour l'observation et l'imagerie de sources astrophysiques. Des conséquences directes sont l'augmentation de la complexité, de l'envergure et de la masse des instruments placés aux foyers de ces télescopes. Une solution passe par l'utilisation de miroirs de formes libres. Or aujourd’hui, obtenir ces formes exotiques via les méthodes traditionnelles de fabrication optique n’est pas possible et un appel à de nouvelles ruptures technologiques s'avère nécessaire. Cette thèse présente un travail de recherche et développement amont portant sur un procédé de fabrication innovant permettant de fournir des miroirs de formes libres, avec les performances optiques requises en observations visibles et infrarouges. Ce procédé est une évolution des techniques d'Optique Active et exploite la déformation plastique des matériaux métalliques. Cependant, le domaine plastique reste un domaine de comportements non-linéaires analytiquement complexes. Il est alors d'intérêt de comparer des modèles par éléments finis avec des essais réels. Ces derniers ont nécessité la mise en place de la gamme complète de fabrication des substrats et des moyens d’essais. Les premiers miroirs obtenus pourront mettre en évidence les paramètres principaux à prendre en compte ainsi que leur niveau de sensibilité, pour ensuite converger vers des modèles éléments finis fiables et une solution de fabrication optique maîtrisée. / The next instrumental decade in astronomy aims to be extreme. It opens with the arrival of ELTs (Extremely Large Telescopes). Their giant primary mirrors will increase the light collecting power and the angular resolution, key parameters for observing and imaging of celestial bodies. However, this also leads to an increase in the complexity, size and weight of their focal-plane instruments, to minimize flux lost and to correct for the aberrations introduced. A solution would be to implement freeform mirrors inside the optical systems of these instruments. Today, it is not possible to obtain these exotic mirror shapes using the current optical fabrication techniques and new technological breakthroughs in this domain are essential. This PhD thesis present research and development work, in upstream phase, of an innovative manufacturing process to supply freeform mirrors, which should meet required optical performances in Visible and Infrared wavelength astronomical observations. This method is an evolution of Active Optics techniques and based on the ability of metallic materials to plasticize. However, the plasticity of metallic materials remains a field of non-linear behaviours and analytically complex. It is important to compare modeling from finite element analysis and real tests. For these tests, the complete manufacturing steps of the metallic substrates were put in place. The first mirrors obtained will highlight the main working parameters and their sensibility levels, and then converge toward reliable finite elements models and a mastered solution of optical freeform mirrors fabrication.

O objetivo do presente trabalho foi o estudo e análise da resposta óptica de dispositivos de cristal fotônico uni-dimensional (1D) fabricados através do uso da tecnologia de silício poroso. Os resultados obtidos neste trabalho apresentam contribuições significativas no desenvolvimento de uma tecnologia para a fabricação de dispositivos ópticos em silício. As principais contribuições deste trabalho estão direcionadas ao aprimoramento dos processos de fabricação de cristais fotônicos 1D e processos de tratamento térmico. Os resultados da análise estrutural através de microscopia óptica de varredura (MEV) e da resposta óptica (refletância ou absorbância) mostraram que dispositivos de cristal fotônico fabricados em soluções altamente diluídas de HF apresentam melhor desempenho, tendo sido otimizado o processo de fabricação utilizando-se uma célula de duplo compartimento (célula dupla). A otimização da resposta óptica dos dispositivos foi atribuída ao efeito de minimização das rugosidades de interface e minimização de efeitos de anisotropia na taxa de corrosão durante o processo de anodização eletroquímica. O processo eletroquímico utilizado para a fabricação de cristais fotônicos 1D apresentou limitação quanto ao número máximo de camadas, sendo observado que dispositivos com número de camadas acima de 60 apresentavam degradação das suas camadas superficiais, comprometendo a resposta óptica do dispositivo. Este resultado foi atribuído a efeitos de diluição química das camadas expostas à solução por longos períodos de processo. Os dispositivos fotônicos 1D mostraram-se sensíveis a processos de recozimento térmico, deslocando suas bandas fotônicas proibidas para regiões de menor comprimento de onda devido à mudança do índice de refração das camadas e aos efeitos de expansão e compressão das camadas constitutivas do dispositivo. Os dispositivos de micocavidade Fabry-Perot mostraram-se mais sensíveis aos processos de recozimento térmico. Os resultados obtidos no presente trabalho vislumbram grandes possibilidades de aplicação dos cristais fotônicos de PS na fabricação de dispositivos ópticos na tecnologia de silício como filtros, lentes, cavidades ressonantes, guias de ondas, grades de difração e dispositivos sensores. / The aim of the present work was to study and analyze the optical response of one- dimensional (1D) photonic crystal devices obtained by using the porous silicon technology. The experimental results obtained from this work showed the significant contribution to the development of a technological process for optical device fabrication in the silicon substrate. The most important contributions of the work are pointed out to improve the electrochemical process for device fabrication and thermal annealing process in order to improve the optical response of the devices. The results obtained from Scanning electronic microscopy (SEM) and from the optical response of the devices, showed that devices fabricated in the double cell and diluted HF solution improved their optical response due to minimization of the anisotropy of corrosion rate and decreasing of the surface roughness between layers. The electrochemical process used for device fabrication showed the existence of limitation on the numbers of layers because of the existence of chemical dissolution effect that became important for long time process. The 1D photonic crystal devices in PS technology showed high sensibility to thermal annealing process, due to the refraction index change after thermal annealing the photonic band gap position shift down to low wavelength region. The Fabry-Perot devices showed higher sensibility to thermal annealing process improving their optical response after annealing process. The results obtained from the present work showed that the PS 1D photonic device could be applied to optical devices fabrication in silicon technology such as optical filters, lenses, resonant cavities, wave-guide devices, diffraction grade and optical sensor device.

Made available in DSpace on 2016-08-10T11:07:12Z (GMT). No. of bitstreams: 1 CARILA APARECIDA DE OLIVEIRA.pdf: 1803945 bytes, checksum: 9bc0a0f802a85183973377ecca4cd7d8 (MD5) Previous issue date: 2015-12-17 / In this thesis, we study the short narratives O mundo crepuscular Hortência, Os três destinos de Luzia and Nos degraus que se bifurcam, in Das estampas, Aguinaldo José Gonçalves, to get to the homological understanding of the creative procedure in which the narratives were woven, seeking generators elements of tension effect; the rhizomatic lines; universes poetic text; the diegetic speech; the dialogues between signs; thematic choices with their mythological overlapping, besides analyzing osmosis look, which form the set of signic movements that interact with each other. For such studies, we seek artists, theorists and critics of literature as Proust, Edgar Alan Poe, Julio Cortázar, for your critical role about short-story and because tale by Gonçalves O mundo crepuscular Hortência refers to Cortázar Continuidade dos parques, and others mentioned or linked to the narratives under study. Thus, the main objective of this study is the analysis short narratives by Gonçalves, highlighting that the stories narrated with their signs work metrically become mere pretexts for the suggestive context of how is the creative procedure of short narrative, in the stylistics of creator of the work that distinguishes the literary art to put in signs and arts dialogue with her artistic that mirrors the selfpoetic speech. / Nesta dissertação, procuramos estudar os contos O mundo crepuscular de Hortência, Os três destinos de Luzia e Nos degraus que se bifurcam, da obra Das estampas, de Aguinaldo José Gonçalves, para se chegar à compreensão mais homológica do procedimento criativo em que as narrativas foram tecidas, buscando os elementos geradores do efeito tensional; as linhas rizomáticas; os universos poéticos textuais; o discurso diegético; os diálogos entre signos; as escolhas temáticas com suas imbricações mitológicas, além de analisar a osmose do olhar, que formam o conjunto dos movimentos sígnicos que dialogam entre si. Para tais estudos, buscamos artistas, teóricos e críticos da Literatura como Proust, Edgar Alan Poe, Julio Cortázar, pela sua atuação crítica sobre contos e porque o conto de Gonçalves O mundo crepuscular de Hortência remete ao de Cortázar Continuidade dos parques, e outros citados ou vinculados às narrativas em estudo. Dessa forma, o objetivo central deste estudo consiste na análise de contos de Gonçalves, destacando que as estórias narradas com seus signos trabalhados metricamente tornam-se meros pretextos para a conjuntura sugestiva de como se dá o procedimento criativo da narrativa curta, sob a estilística do criador da obra que singulariza a arte literária ao por em diálogo signos e artes, com sua artística que espelha o discurso metapoético.

This thesis investigates various active control aspects of large aperture telescopes; both Earth-based and space telescopes are considered.The first part proposes a concept of piezoelectric adaptive thin shell reflector for future space telescopes; it exhibits excellent areal density and stowability, and thus, paves the way to future large aperture space telescopes. Controlling the surface figure of spherical or parabolic shell with in-plane stresses induced by a piezoelectric layer raises two problems: (i) Doubly curved shells are significantly stiffer than flat plates (especially for the optical modes associated with hoop strains) and (ii) When using segmented electrodes with different voltages, the surface figure is subject to edge fluctuations with a characteristic length depending on the reflector curvature R_c and thickness t according to sqrt(R_ct). Accurate surface figure corrections require that the electrode size D_e satisfies D_e<sqrt(R_ct). This results in a very large number of electrodes, leading to ill-conditioning in the Jacobian matrix of the system; to solve this, a hierarchical approach is proposed to inverse the Jacobian, based on Saint-Venant's principle. This chapter also proposes a petal configuration which aims at reducing the hoop stiffness and improving the foldability of the reflector. A small scale technology demonstrator has been manufactured in the framework of the ESA-GSTP project Multilayer Adaptive Thin Shell Reflectors for Future Space Telescopes (MATS). The demonstrator includes a polymer substrate (PEEK) and a spin-coated PVDF-TrFE piezoelectric layer activated by independent electrodes; it is used to validate the manufacturing process and the independent actuation of the electrodes.The second part deals with control-structure interaction in flat deformable mirrors for Adaptive Optics. The problem arises because of the increasing size of AO mirrors, leading to lower resonance frequencies, and the control bandwidth requirements to achieve a good wavefront error compensation. This chapter studies the conditions for spillover instability and highlights the main parameters controlling the phenomenon: the ratio between the control bandwidth and the resonance frequency and the modal damping. Two methods for damping augmentation are discussed, one passive, using inductive shunting of piezoelectric elements, and the other active, using the wavefront sensor and the array of control actuators as a modal filter.The third part focuses on the field stabilization control of the tip/tilt mirror under wind disturbances of the E-ELT telescope (a distinctive feature of the E-ELT as compared to other smaller telescopes is that it will be a wind-limited instead of a seeing-limited telescope). A literature survey is conducted of the spectral content of the wind disturbances on large telescopes, with a special attention on the high frequency decay rate. The analysis confirms the adequacy of a decoupled design of the field stabilization (M5) control loop. However, the reaction torques necessary to control the tip/tilt mirror M5 have been found to depend critically on the asymptotic decay rate of the wind tilt disturbance. These torques act as a disturbance on the telescope structure and, if the wind disturbance does not decay fast enough with the frequency (a>-3), it may generate significant wavefront errors in the primary mirror M1, in a frequency range (30-100Hz) which may be difficult to eliminate by Adaptive Optics. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

A presente dissertação se propôs a analisar quatro fabulários, tendo como fio condutor dessa escolha o Kalla e Dimna, fabulário árabe do século VIII d.C. Partindo desta obra, os estudos se orientaram tanto às suas origens, que remontam à compilação indiana Pañcatantra, datada do século I d.C. e que teve entrada no mundo árabe, bem como aos seus frutos, o Livro do tigre e do raposo e O leão e o chacal Mergulhador, dois fabulários árabes produzidos, respectivamente, nos séculos IX d.C., XI d.C. e XII d.C. e que tiveram, em relação aos anteriores, menor disseminação. Os dois primeiros fabulários tratam de uma série de temas que podem atender às normas mais gerais de decoro na sociedade, sendo que o Pañcatantra chega até mesmo a ser classificado como um tratado sobre a conduta em manuais de literatura sânscrita. Entre esses temas diversos, é notável o espaço privilegiado dado às relações políticas e aos seus trâmites. Os outros dois livros, embora inseridos na mesma tradição, deixam de lado aspectos mais gerais da convivência e passam a se deter apenas nos temas especificamente políticos. No que se refere a esse assunto em comum, é possível perceber uma série de elementos recorrentes nos quatro fabulários, entre eles, o fato de que todos tratam das vicissitudes das relações entre poder e saber, personificada em personagens-tipo que ora se aproximam, ora se afastam, mas que se mantém atrelados a uma estrutura que os molda conforme os resultados que almeja atingir. Além disso, foram estudadas as estruturas que, no caso, se apoiam na maior parte das vezes em narrativas-quadro ou prólogos-moldura a partir dos quais se desenvolvem subnarrativas e outros elementos que nos possibilitaram, ao término do estudo, apontar o que há de particular na universalidade a que se propõem os fabulários. / This dissertation aims to analyze four collections of fables, choosing as the central work from which further analysis will stem the Kalla and Dimna, an Arab collection of fables dating from the VIII century A.D. From this starting point, these studies were furthered by revisiting its origins in the Panchatantra, an Indian compilation of fables from the I century A.D. that left its marks on the Arab world, as well as its developments in the books that directly follow its legacy, the Livro do tigre e do raposo and O leão e o chacal Mergulhador, two arab collections of fables dating, respectively, to the IX century A.D. and the XI and XII century A.D. which had, however, far less dissemination than the last two works here cited. The first two collections develop around a variety of subjects relating to rules regulating manners in a broader sense, to the point that the Panchatantra has been classified as a treatise on manners in Sanskrit literature manuals. Between the diversity of subjects broached, the privileged attention given to political relations and their formalities is readily noticeable. The two other works, though part of the same literary tradition, set aside more general or day-to-day aspects of good manners to focus exclusively on political relations and political conduct. Regarding this shared thematic, a number of recurring elements can be identified, one of many being the fact that all of them deal with the specifics of the relationship stabilished between power and knowledge, personified in character types that alternate between approaching and distancing themselves from one another, but that are always attached to a structure that moulds them according to the results it desires. Beyond that, the narrative structures of the works were studied they usually make use of frame narratives or frame prologues from which further subnarratives are developed along with other elements that made it possible, at the end of this study, to point towards the particularities of the universality that the collections of fables undertake as their purpose.

As the artwork’s title suggests, Penelope Umbrico’s "Mirrors (from Home Décor Catalogs and Websites)" (2001-2011), are photographs of mirrors that Umbrico has appropriated from print and web based home décor advertisements like those from Pottery Barn or West Elm. The mirrors in these advertisements reflect the photo shoot constructed for the ad, often showing plants or light filled windows empty of people. To print the "Mirrors," Umbrico first applies a layer of white-out to everything in the advertisement except for the mirror and then scans the home décor catalog. In the case of the web-based portion of the series, she removes the advertising space digitally through photo editing software. Once the mirror has been singled out and made digital, Umbrico then adjusts the perspective of the mirror so that it faces the viewer. Finally, she scales the photograph of the mirror cut from the advertisement to the size and shape of the actual mirror for sale. By enlarging the photograph, she must increase the file size and subsequent print significantly, which distorts the final printed image thereby causing pixelation, otherwise known as “compression artifacts.” Lastly, she mounts these pixelated prints to non-glare Plexiglas both to remove any incidental reflective surface effects and to create a physical object. What hangs on the wall, then, looks like a mirror in its shape, size and beveled frame: the photograph becomes a one-to-one representation of the object it portrays. When looking at a real mirror, often the viewer is aware of either a reflection of the self or a shifting reflection caused by his or her own movement. However, the image that the "Mirror" ‘reflects’ is not the changing reflection of a real mirror. Nor is it a clear, fixed image of the surface of a mirror. Instead the "Mirrors" present a highly abstract, pixelated surface to meet our eyes. The "Mirrors" are physical objects that merge two forms of representation into one: the mirror and the photograph, thus highlighting similarities between them as surfaces that can potentially represent or reflect almost anything. However, in their physical form, they show us only their pixelation, their digitally constructed nature. Penelope Umbrico’s "Mirrors" are photographs of mirrors that become simultaneously photograph and mirror: the image reflected on the mirror’s surface becomes a photograph, thus showing an analogy between the two objects. In their self-reflexive nature, I argue that Umbrico’s "Mirrors" point to their status as digital photographs, therefore signaling a technological shift from analog to digital photography. Umbrico’s "Mirrors," in altering both mirrors and photographs simultaneously refer to the long history of photography in relation to mirrors. The history of photography is seen first through these objects by the reflective surface of the daguerreotype which mirrored the viewer when observing the daguerreotype, and because of the extremely high level of detail in the photographic image, which mirrored the photographic subject. The relation to the history of photography is also seen in the phenomenon of the mirror within a photograph and the idea that the mirror’s reflection shows the realistic way that photographs represent reality. Craig Owens calls this "en abyme," or the miniature reproduction of a text that represents the text as a whole. In the case of the mirror, this is because the mirror within the photograph shows how both mediums display highly naturalistic depictions of reality. I contend that as an object that is representative of the photographic medium itself, the shift from analog to digital photography is in part seen through the use of the mirror that ultimately creates an absent referent as understood through a comparison of Diego Velázquez’s "Las Meninas" (1656). As Foucault suggests that "Las Meninas" signals a shift in representation from the Classical age to the Modern period, I suggest that the "Mirrors" signal the shift in representation from analog to digital. This latter shift spurred debate among photo history scholars related to the ontology of the photographic medium as scholars were anxious that the ease of editing digital images compromised the photograph’s seeming relationship to truth or reality and that it would be impossible to know whether an image had been altered. They were also concerned with the idea that computers could generate images from nothing but code, removing the direct relationship of the photograph to its subject and thereby declaring the “death” of the medium. The "Mirrors" embody the technological phenomenon with visual addition of “compression artifacts,” otherwise known as pixelation, where this representation of digital space appears not directly from our own creation but as a by-product of digital JPEG programming. In this way they are no longer connected to the subject but only to the digital space they represent. As self-reflexive objects, the "Mirrors" show that there has been a technological transformation from the physically made analog photograph to the inherently mutable digital file.

The purpose of this study is to attain an understanding of my work for the viewer as well as myself. These works on paper are visual documents illustrating my ideas and opinions about media and its desire for control. Through research, critical thinking, experience, and exposure to media (both wanted and unwanted) I have created imagery that I feel is exemplary of our forced relationship with advertising. In order to accomplish this I studied my influences, and the origin of my current work. Reading upon realization of those influences further informed the work. Every conceivable influence was studied and analyzed, and those studies are contained in this thesis. Questions of audience, scale, medium, and history were also taken into account as a measure to make this thesis cohesive. As an audience for advertisers we must constantly be aware of how our sensitivities are being played upon.

Optical fiber sensors have already been developed from the experimental stage to practical applications in the past 20 years. There is no doubt that this technology can bring a wealth of applications, ranging from sensors in medical industry, aerospace and wind-energy industries, through to distributed sensors in oil and gas industry. Among a large amount of physical and chemical parameters which optical fiber sensors could measure, temperature and strain are the most widely studied. This thesis presents several low-cost optical fiber sensor configurations primarily for temperature and strain measurement. Several basic optical fiber components which are good candidates as optical fiber sensors are used in our experiments, such as fiber Bragg gratings (FBGs), multimode fibers (MMFs), small-core dispersion compensation fibers (SCDCFs), high-birefringence fiber loop mirrors (HBFLMs), and polarization-maintaining photonic crystal fibers (PMPCFs). Temperature and strain cross sensitivity is a crucial issue when designing high performance optical fiber sensors, since most of the sensing components are both sensitive to temperature and strain. This would introduce an error when measuring each of them independently. We developed several schemes to overcome this problem by cascading an FBG and a section of MMF, inserting an FBG into an HBFLM, and space division multiplexing two HBFLMs. By measuring the wavelength shifts of the two independent components' spectra in each scheme, simultaneous measurement of temperature and strain could be achieved. However, all the above schemes need optical spectrum analyzers to monitor the spectral information, which increases the cost of the system and limits the operation speed. In order to avoid using optical spectrum analyzers, we use an intensity-based interrogation method with MMFs and HBFLMs as edge filters. By measuring power ratio changes, instead of monitoring spectra shifts, simultaneous measurement of temperature and strain could be realized with a low cost and high speed. The resolutions of the above five configurations are between 0.26 - 1.2 ^oC in temperature and 9.21 - 29.5 με in strain, which are sufficient for certain applications. We also investigate the sensing applications with the SCDCF. Since the cutoff wavelength of this kind of fiber is around 1663 nm, which makes it naturally an MMF in the wavelength range of 1550 nm. By slightly offsetting the core of the SCDCF with respect to that of the standard single-mode fiber (SMF), a high extinction ratio could be achieved with almost 9 dB. When a lateral force (lateral strain) applied on the SCDCF, extinction ratio will decrease. The change of the extinction ratio is almost independent of temperature variation. The measured extinction ratio change has a good quadratic relationship with respect to applied lateral force. This feature could be used to measure lateral force (lateral strain). In addition, we also use this feature to realize simultaneous measurement of both the longitudinal strain and lateral strain, since the applied longitudinal strain results in the whole spectrum shift. Moreover, a miniature high temperature sensor could also be made using the SCDCF. One end of a 4-mm long SCDCF is spliced directly to SMF with the other end cleaved. By monitoring the reflection spectrum of the SCDCF, temperature information could be obtained. This sensing head is very compact and could realize high temperature measurement up to 600 ^oC. Recently, a kind of PMPCF has been found to have very small responses to temperature change. This offers an opportunity to measure other parameters without considering temperature influence. We construct a compact 7-mm long transmission-type sensor with this kind of PMPCF. The interference spectrum generated by the coupling of cladding modes and core mode is obtained by slightly offsetting the PMPCF core to SMF core. The experiment shows that the interference spectrum is almost unchanged within the temperature range of 25-60 ^oC. The presented sensor has the potential to be used to measure strain and refractive index in the normal environment without temperature discrimination for practical applications.