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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Looks Good To Me (LGTM): Authentication for Augmented Reality

Gaebel, Ethan Daniel 27 June 2016 (has links)
Augmented reality is poised to become the next dominant computing paradigm over the course of the next decade. With the three-dimensional graphics and interactive interfaces that augmented reality promises it will rival the very best science fiction novels. Users will want to have shared experiences in these rich augmented reality scenarios, but surely users will want to restrict who can see their content. It is currently unclear how users of such devices will authenticate one another. Traditional authentication protocols reliant on centralized authorities fall short when different systems with different authorities try to communicate and extra infrastructure means extra resource expenditure. Augmented reality content sharing will usually occur in face-to-face scenarios where it will be advantageous for both performance and usability reasons to keep communications and authentication localized. Looks Good To Me (LGTM) is an authentication protocol for augmented reality headsets that leverages the unique hardware and context provided with augmented reality headsets to solve an old problem in a more usable and more secure way. LGTM works over point to point wireless communications so users can authenticate one another in any circumstance and is designed with usability at its core, requiring users to perform only two actions: one to initiate and one to confirm. LGTM allows users to intuitively authenticate one another, using seemingly only each other's faces. Under the hood LGTM uses a combination of facial recognition and wireless localization to ensure secure and extremely simple authentication. / Master of Science
42

Aplicação da holografia computacional para o cálculo de elementos ópticos difrativos / not available

Roberto, Luciana Brassolatti 13 April 2000 (has links)
A Holografia Computacional é uma técnica bem conhecida que permite a realização de uma grande variedade de Elementos Ópticos Difrativos. Elementos Ópticos Difrativos são dispositivos ópticos \"moldadores\" de onda projetados com base nas propriedades de difração de suas interfaces micro-estruturadas (ou de seus variáveis índices de refração). Considerando-se sua vasta escala de tecnologias de integração e repetição, usadas na fabricação de circuitos micro-eletrônicos, eles possuem um baixo custo de fabricação. Neste trabalho, o Algoritmo Iterativo da Transformada de Fourier foi aplicado para o cálculo de hologramas de Fourier binários destinados à modelagem da luz laser. A finalidade foi simular as propriedades dos elementos, considerando algumas distribuições luminosas desejadas, e gerar o \"layout\" das máscaras de fabricação destes hologramas. Urna das implementações realizadas, para que os resultados fossem melhorados durante as iterações, foi o cálculo de uma correção na janela de reconstrução que considera o erro de amplitude da reconstrução anterior. A possibilidade de visualizar as reconstruções binárias também é demonstrada, onde o olho humano é tratado como uma lente de Fourier. Um dispositivo óptico difrativo híbrido com perfil binário e contínuo, capaz de dividir um feixe de laser monocromático em um número arbitrário de linhas com um alto ângulo também é apresentado. Hologramas de Fourier de fase contínua e com 4 níveis de fase são implementados utilizando-se o Algoritmo Iterativo da Transformada de Fourier. Cálculos para a geração de hologramas de fase de Fresnel são realizados, combinando o Algoritmo Iterativo da Transformada de Fourier com a propagação da luz no espaço livre. / The Computer Holography is a well known technique that enables one to realize a wide range of Diffractive Optical Elements. Diffractive Optical Elements are optical waveshaping devices designed with base on the diffraction properties of their microstructured interfaces (or refractive-index gradients). They have potential low fabrication cost, considering their very large scale integration and replication technologies used in the fabrication of microelectronics circuits. In this work, the Iterative Fourier Transform Algorithm was applied for the calculation of binary computer generated Fourier holograrns for laser beam shaping. The purpose was to simulate the elements proprieties considering some desired light distributions and to generate the fabrication masks Iayout of these holograms. One of the implementations, performed to improve the results during the iterations, was the calculation of a amplitude correction in the reconstruction window that considers the amplitude error from the previous reconstruction. The possibility to visualize the binary holograms reconstructions is also demonstred, where the human eye is treated as a Fourier lens. A hybrid binary and continuous profile diffractive optical device capable of splitting a monochromatic laser beam into an arbitrary number of tines over wide angle is also presented. Continuous phase and four phase levels Fourier holograms are implemented using the lterative Fourier Transform Algorithm. Fresnel phase holograms calculations are performed by combining the Iterative Fourier Transform Algorithm with the free space light propagation.
43

Aplicação da holografia computacional para o cálculo de elementos ópticos difrativos / not available

Luciana Brassolatti Roberto 13 April 2000 (has links)
A Holografia Computacional é uma técnica bem conhecida que permite a realização de uma grande variedade de Elementos Ópticos Difrativos. Elementos Ópticos Difrativos são dispositivos ópticos \"moldadores\" de onda projetados com base nas propriedades de difração de suas interfaces micro-estruturadas (ou de seus variáveis índices de refração). Considerando-se sua vasta escala de tecnologias de integração e repetição, usadas na fabricação de circuitos micro-eletrônicos, eles possuem um baixo custo de fabricação. Neste trabalho, o Algoritmo Iterativo da Transformada de Fourier foi aplicado para o cálculo de hologramas de Fourier binários destinados à modelagem da luz laser. A finalidade foi simular as propriedades dos elementos, considerando algumas distribuições luminosas desejadas, e gerar o \"layout\" das máscaras de fabricação destes hologramas. Urna das implementações realizadas, para que os resultados fossem melhorados durante as iterações, foi o cálculo de uma correção na janela de reconstrução que considera o erro de amplitude da reconstrução anterior. A possibilidade de visualizar as reconstruções binárias também é demonstrada, onde o olho humano é tratado como uma lente de Fourier. Um dispositivo óptico difrativo híbrido com perfil binário e contínuo, capaz de dividir um feixe de laser monocromático em um número arbitrário de linhas com um alto ângulo também é apresentado. Hologramas de Fourier de fase contínua e com 4 níveis de fase são implementados utilizando-se o Algoritmo Iterativo da Transformada de Fourier. Cálculos para a geração de hologramas de fase de Fresnel são realizados, combinando o Algoritmo Iterativo da Transformada de Fourier com a propagação da luz no espaço livre. / The Computer Holography is a well known technique that enables one to realize a wide range of Diffractive Optical Elements. Diffractive Optical Elements are optical waveshaping devices designed with base on the diffraction properties of their microstructured interfaces (or refractive-index gradients). They have potential low fabrication cost, considering their very large scale integration and replication technologies used in the fabrication of microelectronics circuits. In this work, the Iterative Fourier Transform Algorithm was applied for the calculation of binary computer generated Fourier holograrns for laser beam shaping. The purpose was to simulate the elements proprieties considering some desired light distributions and to generate the fabrication masks Iayout of these holograms. One of the implementations, performed to improve the results during the iterations, was the calculation of a amplitude correction in the reconstruction window that considers the amplitude error from the previous reconstruction. The possibility to visualize the binary holograms reconstructions is also demonstred, where the human eye is treated as a Fourier lens. A hybrid binary and continuous profile diffractive optical device capable of splitting a monochromatic laser beam into an arbitrary number of tines over wide angle is also presented. Continuous phase and four phase levels Fourier holograms are implemented using the lterative Fourier Transform Algorithm. Fresnel phase holograms calculations are performed by combining the Iterative Fourier Transform Algorithm with the free space light propagation.
44

EU:s nya varumärkesdefinition : En utredning av vad borttagandet av kravet på grafisk återgivning kommer att innebära för möjligheten att registrera okonventionella varumärken / The new trade mark definition in the EU : An investigation of the effects the removal of the requirement for graphical representation will have on the possibility to register non-conventional trade marks

Fredriksson, Mathilda, Petersson, Frida January 2017 (has links)
Sedan det första steget togs mot en harmoniserad varumärkesrätt inom EU har grafisk återgivning varit ett krav vid registrering av varumärken, men kravet på grafisk återgivning försvinner i och med EU:s nya varumärkesreform. Syftet med denna uppsats är att belysa och utreda vad detta kommer att innebära för möjligheten att registrera okonventionella varumärken. Utredningen är inriktad på följande okonventionella varumärken: doftmärken, smakmärken, ljudmärken, känselmärken, rörelsemärken och hologram. Syftet med kravet på grafisk återgivning har varit att föremålet för varumärkesskyddet ska fastställas på ett exakt sätt, men kravet har lett till att okonventionella varumärken, särskilt sådana som inte kan uppfattas visuellt, har varit svåra att registrera. Genom en granskning av äldre rättspraxis på området identifieras de specifika problem, avseende den grafiska återgivningen, som finns för vart och ett av de utvalda okonventionella varumärkena. Resultatet av granskningen ligger, tillsammans med en analys av den ändrade varumärkesdefinitionen, till grund för utredningen av de konsekvenser som ändringarna, särskilt borttagandet av kravet på grafisk återgivning, kommer att få för möjligheten att registrera okonventionella varumärken. Resultatet av analysen indikerar att möjligheten att registrera okonventionella varumärken kommer att öka i och med att det framförallt är den grafiska återgivningen som har orsakat problemen vid registrering. En teknikneutral återgivning gör det möjligt att använda nya återgivningsmetoder, vilket i sin tur leder till att de krav som ställs på återgivningen, bland annat att den ska vara klar och lättillgänglig, kan uppfyllas på ett bättre sätt än tidigare. / Graphical representation has been a requirement for registration of non-conventional trade marks since the first step was taken towards a harmonized trade mark regulation in the EU. The requirement for graphical representation was removed as a result of the new trade mark reform. The purpose of this thesis is to illuminate and investigate how the removal of the requirement for graphical representation will affect the possibility to register non-conventional trade marks. The investigation focuses on the following non-conventional trade marks: scent marks, taste marks, sound marks, touch marks, motion marks and holograms. The purpose of the requirement for graphical representation has been to determine the precise nature and extent of the protection that the registered mark provides to its proprietor. However, the requirement has led to difficulties regarding registration of non-conventional trade marks, especially trade marks that cannot be perceived visually. The specific problems, regarding graphical representation, for each one of the selected trade marks, are identified through a review of earlier case-law. The result of the review of the earlier case-law and a review of the new trade mark definition, make up the foundation of the analysis of the consequences the removal of the graphical representation will have on the possibility to register non-conventional trade marks. The result of the analysis indicates that the possibility to register non-conventional trade marks will increase as a result of the removal of the requirement for graphical representation, as it is the graphical representation that has caused most problems for non-conventional trade marks during the registration process. As there is no longer a requirement for the representation to be graphical, it will be possible to use new methods for representation. This will in turn lead to that the criteria the representation must meet, for example that it must be clear and easily accessible, can be better achieved than before.
45

Počítačem generované hologramy / Computer Generated Holograms

Tvarog, Drahoslav January 2010 (has links)
The presented Diploma thesis deals with the computer-generated diffractive structures or rather called computer generated holograms (CGH). We follow basic principles of classical holography and in the context of which we define a synthetic holography. We then show various types of digital holograms and methods of measurement of their quality. We deal with several iterative algorithms useful for computation of the Fourier transform as well as with methods of phase quantization. In the second part of the work, we describe briefly our computer code for iterative Fourier transform computation. With respect to the mentioned techniques, we further present the usability of the method for design of computer generated holograms in reflection regime. After a short introduction to the electron beam lithography and its exploitation for the origination of computer generated diffractive optical elements. We analyze reconstructions of produced holograms and evaluate its quality.
46

Artificially yours : En studie av tre konstruerade kvinnor i 2010-talets science fiction-film / Artificially Yours : A study of three constructed women in science fiction film of the 2010s

Lahti, Aron January 2019 (has links)
Artificiella kvinnor har porträtterats efter vissa tematiska utgångspunkter genom kulturhistorien, där Ovidius Pygmalion-myt varit en dominerande tematik. Frågan om artificiella människor är också tätt förknippad med science fiction-genren, och även där har bilden om den ensamme mannen som skapar sig en kvinna ofta återkommit. I denna uppsats jämförs tre science fiction-filmer från 2010-talet - Her (Spike Jonze, 2013), Ex Machina (Alex Garland, 2014) och Blade Runner 2049 (Denis Villeneuve, 2017) - för att utröna hur artificiell femininitet konstruerad av män tar sig uttryck: vilken tematik som är jämförbar med äldre porträtteringar av artificiella kvinnor, och vad dessa samtida inkarnationer kan säga om heteronormativitet inom science fiction-genren i dag och i framtiden. Denna analys görs dels mot bakgrund av nyckelverk inom litteratur och film, delvis genom begrepp som performativitet och andrafiering inom genus- och queerteori.
47

Modelagem In silico de propriedades farmacocinéticas para a avaliação de candidatos a novos fármacos / Pharmacokinetic Properties In Silico Modeling for New Chemical Entities Evaluation.

Moda, Tiago Luiz 30 August 2011 (has links)
Os processos farmacocinéticos de absorção, distribuição, metabolismo e excreção (ADME), têm sido identificados como as principais causas do insucesso de candidatos a fármacos em estágios avançados de desenvolvimento clínico. As metodologias modernas de modelagem in silico de propriedades farmacocinéticas estão integradas ao processo de planejamento de fármacos, sendo de extremo valor na identificação e seleção de novas entidades químicas candidatas a fármacos. Esta área emergente está atraindo grande atenção da indústria farmacêutica mundial, que tem integrado a otimização de múltiplas propriedades farmacodinâmicas e farmacocinéticas em todos os estágios de projetos de pesquisa e desenvolvimento (P&D). As propriedades farmacocinéticas podem ser estudadas através do uso de métodos in silico como o estudo das relações quantitativas entre a estrutura e atividade (QSAR), ou estrutura e propriedade (QSPR), entre outros. O trabalho desenvolvido nesta tese de doutorado teve como importante objetivo estudar as relações quantitativas entre a estrutura química e propriedades farmacocinéticas como absorção intestinal, metabolismo de primeira passagem mediado pelo CYP, permeabilidade da barreira hematoencefálica, bem como eventos de extremo interesse que as influenciem como a inibição da glicoproteína-P e solubilidade aquosa. Para a realização deste trabalho, conjuntos padrões de dados foram organizados para as propriedades farmacocinéticas contendo a informação qualificada sobre a estrutura química e a propriedade alvo correspondente. Os conjuntos de dados criados formaram as bases científicas para o desenvolvimento dos modelos preditivos empregando o método holograma QSAR (HQSAR). Os modelos finais de HQSAR gerados neste trabalho possuem elevada consistência interna e externa, apresentando bom poder de correlação e predição das propriedades alvo. Os modelos desenvolvidos, assim como os dados farmacocinéticos coletados, foram disponibilizados para acesso livre através da internet na base de dados PK/DB (www.pkdb.ifsc.usp.br). Devido à simplicidade, robustez e consistência, estes modelos são guias úteis em Química Medicinal nos estágios iniciais do processo de descoberta e desenvolvimento de fármacos. / The pharmacokinetic (PK) processes of absorption, distribution, metabolism and excretion (ADME), have been identified as one of the major causes of new chemical entities (NCEs) failure in early clinical trials. In silico models are receiving increased attention in recent years from the pharmaceutical industry, which is integrating a paradigm of multiple pharmacodynamic and pharmacokinetic properties optimization for the development of NCEs. ADME properties can be studied by in silico methods, such as quantitative structure-activity relationships (QSAR) or structure-property (QSPR), among other methodologies. The main goal of this PhD thesis was to study the quantitative relationships between chemical structure and pharmacokinetic properties, such as intestinal absorption, CYP mediated first pass metabolism, blood brain barrier permeability, as well as other important events that have influence on these PK properties, such as P-glycoprotein inhibition and water solubility. In the present work, standard data sets were organized encompassing the structural information and corresponding pharmacokinetic data. The standard data sets established the scientific basis for the development of predictive models using the hologram QSAR (HQSAR) method. The final HQSAR models possess high internal and external consistency with good correlative and predictive power for endpoint PK properties. All in silico models generated and standard data sets are freely available on the internet through the Database for Pharmacokinetic Properties (PK/DB - www.pkdb.ifsc.usp.br). Due to the simplicity, robustness and effectiveness, these models are useful guides in Medicinal Chemistry in the early stages of the drug discovery and development process.
48

Three-dimensional Holographic Lithography and Manipulation Using a Spatial Light Modulator

Jenness, Nathan J. January 2009 (has links)
<p>This research presents the development of a phase-based lithographic system for three-dimensional micropatterning and manipulation. The system uses a spatial light modulator (SLM) to display specially designed phase holograms. The use of holograms with the SLM provides a novel approach to photolithography that offers the unique ability to operate in both serial and single-shot modes. In addition to the lithographic applications, the optical system also possesses the capability to optically trap microparticles. New advances include the ability to rapidly modify pattern templates for both serial and single-shot lithography, individually control three-dimensional structural properties, and manipulate Janus particles with five degrees of freedom.</p><p>A number of separate research investigations were required to develop the optical system and patterning method. The processes for designing a custom optical system, integrating a computer aided design/computer aided manufacturing (CAD/CAM) platform, and constructing series of phase holograms are presented. The resulting instrument was used primarily for the photonic excitation of both photopolymers and proteins and, in addition, for the manipulation of Janus particles. Defining research focused on the automated fabrication of complex three-dimensional microscale structures based on the virtual designs provided by a custom CAD/CAM interface. Parametric studies were conducted to access the patterning transfer rate and resolution of the system.</p><p>The research presented here documents the creation of an optical system that is capable of the accurate reproduction of pre-designed microstructures and optical paths, applicable to many current and future research applications, and useable by anyone interested in researching on the microscale.</p> / Dissertation
49

A Tunable Snapshot Imaging Spectrometer

Tebow, Christopher January 2005 (has links)
A tunable snapshot imaging spectrometer has been demonstrated. A liquid crystal spatial light modulator (LC SLM) has been integrated into a computed tomographic imaging spectrometer (CTIS) to achieve tunability. The LC SLM allows for rapid, programmable, and non-mechanical alteration of its phase profile by the application of appropriate voltages to its transparent electrodes.The goal of this dissertation is twofold: (1) to integrate a liquid crystal spatial light modulator into a CTIS instrument and characterize its performance as a tunable CTIS disperser, and (2) to implement tunability by analyzing different CTIS configurations.The theoretical model of CTIS operation, calibration, reconstruction, and disperser design are covered in detail. The cross talk of the LC SLM forces the use of a feedback design algorithm rather than designing the desired phase profile a priori in the computer. The modifications to the current polychromatic linear inversion technique for use with the LC SLM in feedback are presented. The result of the modifications is the successful integration of a reprogrammable (i.e. tunable) disperser for the CTIS instrument.The implementation of tunability is explored by analyzing the spectral resolution of a reconstructed point source for different disperser configurations. A method for experimentally determining the CTIS spectral resolution is presented.
50

Confocal acoustic holography for non-invasive 3D temperature and composition measurement

Atalick, Stefan 03 May 2007 (has links)
This thesis summarizes my work at the University of Victoria to design and evaluate a proof-of-concept instrument called the Confocal Acoustic Holography Microscope (CAHM). The instrument will be able to measure small changes in temperature and composition in a fluid specimen, which can be indirectly measured via small fluctuations in the speed of sound. The CAHM combines concepts of confocal microscopy, interferometry, and ultrasonic imaging. This recent work in confocal acoustic holography has progressed from our previous research in confocal laser holography. The prototype CAHM design uses a frequency of 2.25 MHz, and can measure sound speed changes of 16 m/s, temperature changes of 5°C, with a spatial resolution of 660 μm. With future improvements to the CAHM, utilizing the latest technologies such as 2D array detectors, MEMS, and acoustic lenses, we expect resolutions of 1 m/s, 0.5°C, and 150 μm. The design of the CAHM involved the production of a 3D CAD layout of the optomechanical components and ray tracing simulations using Zemax optical design software. Simulated acoustic holograms and fringe shifts were produced and they were found to match up very well with theoretical calculations. A simplified acoustic holography instrument was built and tested. Speed of sound measurements were made for several test specimens, while keeping temperature constant. Specimens of ethanol, isopropanol, acetic acid, glycerine, and mineral oil were measured. Holograms were collected for acetic acid and mineral oil and were compared to the reference case (distilled water). The fringe spacing and phase shifts measured experimentally matched up well with the Zemax simulations and the theoretical calculations. Hence, the popular Zemax optical software can be effectively used to design acoustic instruments. To our knowledge, this is the first use of Zemax for acoustic designs. Based on the successful results of the simulations and experiments, the CAHM is expected to have many useful applications, especially in medical diagnostics where it could be used to measure density and temperature within the human body. Phase contrast images could also be used to help identify suspicious lesions, such as those found in prostate or breast tissue. Other applications include non-destructive testing of electronic and mechanical parts, measurements of fluid samples, material science experiments, and microgravity experiments, where non-invasive examination is required.

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