Dissertations / Theses on the topic 'COMPUTER-GRAPHICS DEVICES'

Computer Aided Teaching System (CATSY) is an interactive graphics system, utilizing current microcomputer technology, along with a graphics tablet and a large screen projection system to enhance lecture presentations. Included in this thesis are descriptions of the supporting graphics software (POLY-ReGIS) and the computer peripherals used in the development of CATSY.The development of interactive graphics is stressed in this thesis. Applications of these graphics to CATSY are presented and an introduction to the data structures used in this system is also given. This thesis is intended to support and complement the masters thesis presented by Mr. John Raab, which deals primarily with the system implementation, data structures and the text editor used in CATSY.

Thesis (M.S. in Computer Science)--Naval Postgraduate School, December 2004.
Thesis advisor(s): Neil C. Rowe, Gurminder Singh. Includes bibliographical references (p. 59-65). Also available online.

This thesis explores Voxel Cone Tracing as a possible Global Illumination solutionon mobile devices.The rapid increase of performance on low-power graphics processors hasmade a big impact. More advanced computer graphics algorithms are now possi-ble on a new range of devices. One category of such algorithms is Global Illumi-nation, which calculates realistic lighting in rendered scenes. The combinationof advanced graphics and portability is of special interest to implement in newtechnologies like Virtual Reality.The result of this thesis shows that while possible to implement a state of theart Global Illumination algorithm, the performance of mobile Graphics Process-ing Units is still not enough to make it usable in real-time.

Thesis (M.S.) -- Worcester Polytechnic Institute.
Keywords: mobile devices; photon mapping; global illumination; ray tracing; energy; mobile; computer graphics. Includes bibliographical references (leaves 66-68).

Individuals who suffer from severe motor disabilities face the possibility of the loss of speech. A Brain-Computer Interface (BCI) can provide a means for communication through non-muscular control. Current BCI systems use characters that flash from gray to white (GW), making adjacent character difficult to distinguish from the target. The current study implements two types of color stimulus (grey to color [GC] and color intensification [CI]) and I hypotheses that color stimuli will; (1) reduce distraction of nontargets (2) enhance target response (3) reduce eye strain. Online results (n=21) show that GC has increased information transfer rate over CI. Mean amplitude revealed that GC had earlier positive latency than GW and greater negative amplitude than CI, suggesting a faster perceptual process for GC. Offline performance of individual optimal channels revealed significant improvement over online standardized channels. Results suggest the importance of a color stimulus for enhanced response and ease of use.

Mobile technology is improving in quality and capability faster now than ever before. When first introduced, cell phones were strictly used to make voice calls; now, they play satellite radio, MP3s, streaming television, have GPS and navigation capabilities, and have multi-megapixel video cameras. In the near future, cell phones will have programmable graphics processing units (GPU) that will allow users to play games similar to those currently available for top-of-the-line game consoles. Personal digital assistants enable users with full email, scheduling, and internet browsing capabilities in addition to those features offered on cell phones. Underlying all this mobile technology and entertainment is a battery whose technology has just barely tripled in the past 15 years, compared to available disk capacity that has increased over 1,000-fold. Ray tracing is a rendering technique used to generate photorealistic images that include reflections, refraction, participating media, and can fairly easily be extended to include photon mapping for indirect illumination and caustics. In recent years, ray tracing has been implemented on the GPU using various acceleration structures to facilitate rendering. Until now, all studies have used build time and achievable frame rates to determine which acceleration structure is best for ray tracing. We present the very first results comparing both CPU and GPU raytracing using various acceleration structures in terms of energy consumption. By exploring per-pixel costs, we provide insight on the energy consumption and frame rates that can be experienced on cell phones and other mobile devices based on currently available screen resolutions. Our results show that the choice in processing unit has the greatest affect on energy and time costs of ray tracing, followed by the size of the viewport used, and the choice of acceleration structure has the least impact on efficiency. For mobile devices enabled with a programmable GPU, whether it is a cell phone, PDA, or laptop computer, a bounding volume hierarchy implemented on the GPU is the most energy-efficient acceleration structure for ray tracing. Ray tracing on cellular phones with smaller screen resolutions is most energy-efficient using a CPU-based Kd-Tree implementation.

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O propósito de um objeto simulador é representar a alteração do campo de radiação provocada pela absorção e espalhamento em um dado tecido ou órgão de interesse. Suas características geométricas e de composição devem estar próximos o máximo possível aos valores associados ao seu análogo natural. Estruturas anatômicas podem ser transformadas em objetos virtuais 3D por técnicas de imageamento médico (p. ex. Tomografia Computadorizada) e impressas por prototipagem rápida utilizando materiais como, por exemplo, o ácido poliláctico. Sua produção para pacientes específicos requer o preenchimento de requisitos como a acurácia geométrica com a anatomia do individuo e a equivalência ao tecido, de modo que se possa realizar medidas utilizáveis, e ser insensível aos efeitos da radiação. O objetivo desse trabalho foi avaliar o comportamento de materiais impressos 3D quando expostos a feixes de fótons diversos, com ênfase para a qualidade de radiotherapia (6 MV), visando a sua aplicação na dosimetria clínica. Para isso foram usados 30 dosímetros termoluminescentes de LiF:Mg,Ti. Foi analisada também a equivalência entre o PMMA e o PLA impresso para a resposta termoluminescente de 30 dosímetros de CaSO4:Dy. As irradiações com feixes de fótons com qualidade de radioterapia foram simuladas com o uso do sistema de planejamento Eclipse™, com o Anisotropic Analytical Algorithm e o Acuros® XB Advanced Dose Calculation algorithm. Além do uso do Eclipse™ e dos testes dosimétricos, foram realizadas simulações computacionais utilizando o código MCNP5. As simulações com o código MCNP5 foram realizadas para calcular o coeficiente de atenuação de placas impressas expostas a diversas qualidades de raios X de radiodiagnóstico e para desenvolver um modelo computacional de placas impressas 3D.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

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O aumento na longevidade humana fez surgir uma série de doenças com a idade; em contrapartida o avanço da medicina possibilitou o diagnóstico precoce e o tratamento de várias doenças antes incuráveis. Esse cenário atual estendese também aos animais domésticos (cães e gatos - PETs) que dobraram sua expectativa de vida nas últimas décadas, fato que os humanos demoraram séculos para alcançar. Do mesmo modo que os humanos, esse aumento na longevidade dos animais veio acompanhado de doenças relacionadas com a idade, entre elas o câncer. Uma das terapias utilizadas atualmente no tratamento do câncer é a radioterapia, técnica que utiliza a radiação ionizante para destruir as células tumorais (volume-alvo) com mínimo prejuízo aos tecidos circunvizinhos sadios (órgãos de risco). Essa técnica exige a realização periódica de testes de controle de qualidade, incluindo a dosimetria com a utilização de objetos simuladores equivalentes ao tecido, de modo a verificar a dose de radiação recebida pelo paciente em tratamento e compará-la posteriormente com a dose de radiação calculada pelo sistema de planejamento. A rápida expansão do mercado de impressoras 3D abriu caminho para uma revolução na área da saúde. Atualmente os objetos simuladores por impressão 3D estão sendo usados em planejamentos de Radioterapia para a localização espacial e mapeamento das curvas de isodose, realizando, assim, um planejamento mais personalizado para cada campo de radiação, além da confecção de implantes dentais, customização de próteses e confecção de bólus. Diante do exposto esse trabalho projetou e desenvolveu um objeto simulador chamado de \"Canis Morphic\" utilizando uma impressora 3D e materiais tecido-equivalentes para a realização dos testes de controle de qualidade e otimização das doses na área de Radioterapia em animais (cães). Os resultados obtidos demonstraram-se promissores na área de criação de simuladores por impressão 3D, com materiais de baixo custo, para aplicação no controle de qualidade em Radioterapia veterinária.
Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

X windows is a graphic display management system. It is designed to work on a variety of machines and display adapters, however it is not designed for terminals with local graphics capabilities. X windows can be made to work on this type of terminal, although in a slower and restricted form. The problem with designing a variation of X for these terminals is the translation from X requests to native graphics commands, and the mapping of terminal input into X events. These implementation issues are discussed and example code is provided.
Department of Computer Science

The scope of this project describes World Wide Graphics (WWG) a software package that provides instructors with the tools needed to present a web-based presentation to a group of students while having the ability of enhancing the prepared HTML slide with userdrawn graphics and highlighting.

With the development of the computer networks, mainly the Internet, it became easier to develop applications where the execution is shared between a local computer, the Client, and one located on the other side of the network communication channel, the Server. The hardware advancements in the recent years made it possible to display 3D graphics (games, map navigation, virtual worlds) on mobile devices. However, executing these complex applications on the client terminal is not possible without reducing the quality of the displayed graphics or lowering its processing requirements. Different solutions have already been proposed in academic publications; however none of them satisfies all requirements. The objective of this thesis is to propose an alternative solution for a new client-server architecture where the connectedness of the mobile devices is fully exploited. Several main requirements are addressed: - Minimize the network traffic, - Reduce the required computational power on the terminal, and - Preserve the user experience compared with local execution. First a formal framework is designed that can effectively define and model distributed applications for 3D graphics. Then a model of new architecture is presented, that overcomes the disadvantages of the architectures presented in the state of the art. The core of the architecture is the MPEG-4 standard, which is used to transfer the data between the server and the client in a compressed manner. The last part of explores the design of architectures optimized for running on mobile devices. The design of the new client-server architecture is validated by implementing a game and running simulations.

Für den Zugang zu grafischen Benutzungsoberflächen (GUIs) stehen blinden Menschen so genannte Screenreader und Braillezeilen zur Verfügung. Diese ermöglichen zwar das nicht-visuelle Wahrnehmen textueller Inhalte, allerdings kein effektives Arbeiten mit bildlichen Darstellungen. Neuartige taktile Flächendisplays können eine geeignete Lösung für den interaktiven Zugang zu tastbaren Grafiken darstellen und somit die Interaktionsmöglichkeiten blinder Benutzer im Umgang mit grafischen Anwendungen bereichern. Beispielsweise erlauben derartige Geräte nicht nur das Erkunden räumlicher Anordnungen, sondern darüber hinaus auch die kombinierte Ausgabe von Braille, Grafik und semi-grafischen Elementen. Um die deutlich größere Menge an gleichzeitig darstellbaren Informationen beherrschbar zu machen, sind neben entsprechenden Inhaltsaufbereitungen und Navigationsmechanismen auch geeignete Orientierungshilfen bereitzustellen. Im Rahmen der vorliegenden Arbeit wurde am Beispiel der BrailleDis Geräte der Metec AG, welche eine taktile Ausgabefläche von 120 mal 60 Stiften bereitstellen, untersucht, inwieweit flächige Brailledisplays blinden Menschen eine effektive und effiziente Bedienung grafischer Benutzungsoberflächen ermöglichen. Neben dem Zugang zur GUI selbst sowie dem Lesen von Texten stellt dabei insbesondere das Arbeiten mit Grafiken einen wichtigen Aspekt dar. Um die Bedienung auf einem taktilen Flächendisplay zu erleichtern, ist eine konsistente Organisation der Inhalte hilfreich. Hierfür wurde ein neuartiges taktiles Fenstersystem umgesetzt, welches die Ausgabe nicht nur in mehrere disjunkte Bereiche unterteilt, sondern auch verschiedene taktile Darstellungsarten unterstützt. Zur Systematisierung der Gestaltung und Evaluation derartiger taktiler Benutzungsoberflächen sowie der darin stattfindenden Benutzerinteraktionen wurde zunächst eine Taxonomie erarbeitet. Dabei wurden neben der Interaktion selber, welche durch die Ein-und Ausgabe sowie die Handbewegungen des Benutzers beschrieben werden kann, auch die Benutzerintention in Form von taktilen Elementaraufgaben sowie die technischen Spezifikationen des Geräts mit einbezogen. Basierend auf der Taxonomie wurden anschließend relevante Aspekte identifiziert, welche in mehreren Benutzerstudien mit insgesamt 46 blinden und hochgradig sehbehinderten Menschen untersucht wurden. Die betrachteten Untersuchungsfragen betrafen dabei einerseits die Effektivität der Ausgabe in Form verschiedener taktiler Ansichtsarten sowie die Eingabe und Erkundung durch den Benutzer, andererseits auch Aspekte zur Effizienz konkreter Interaktionstechniken. Als Ergebnis der einzelnen Studien wurden abschließend konkrete Empfehlungen zur Umsetzung von Benutzungsoberflächen auf flächigen Brailledisplays gegeben. Diese beinhalten insbesondere Aspekte zur Ergonomie von taktilen Flächendisplays, zur Anzeige von textuellen Inhalten, zur Darstellung und Interaktion mit grafischen Inhalten sowie zu Orientierungshilfen. Insgesamt konnte mit Hilfe der Benutzerstudien gezeigt werden, dass flächige Brailledisplays blinden Menschen einen effektiven und effizienten Zugang zu grafischen Benutzungsoberflächen ermöglichen. Verschiedene taktile Darstellungsarten können dabei das Lösen unterschiedlicher Aufgaben unterstützen. Generell erfordert die flächige Interaktion vom Benutzer allerdings auch die Erweiterung seiner konventionellen Erkundungs-und Eingabestrategien. Die Bereitstellung neuartiger Interaktionstechniken zur Unterstützung der Orientierung kann die Effizienz zusätzlich steigern
Blind people normally use screen readers as well as single-lined refreshable Braille displays for accessing graphical user interfaces (GUIs). These technologies allow for a non-visual perception of textual content but not for an effective handling of visual illustrations. Novel two-dimensional tactile pin-matrix devices are an appropriate solution to interactively access tactual graphics. In this way, they can enrich the interaction possibilities of blind users in dealing with graphical applications. For instance, such devices enable the exploration of spatial arrangements and also combine output of Braille, graphics and semi-graphical elements. To make the high amount of simultaneously presented information perceivable and efficiently usable for blind users, an adequate preparation of content as well as adapted navigation and orientation mechanisms must be provided. In this thesis the BrailleDis devices of Metec AG, which have a tactile output area of 120 times 60 pins, were used. The goal was to investigate to what extent large pin-matrix devices enable blind people to use graphical user interfaces effectively and efficiently. Access to the GUI itself, reading text, and dealing with graphics are the main aspects of the application area of such devices. To facilitate the operation on a two-dimensional pin-matrix device a consistent organization of the content is helpful. Therefore, a novel tactile windowing system was implemented which divides the output area into multiple disjunctive regions and supports diverse tactile information visualizations. Moreover, a taxonomy was developed to systematize the design and evaluation of tactile user interfaces. Apart from interaction that can be described by input and output as well as hand movements, the taxonomy includes user intention in terms of interactive task primitives and technical specifications of the device. Based on the taxonomy, relevant aspects of tactile interaction were identified. These aspects were examined in multiple user studies with a total of 46 blind and visually impaired participants. The following research topics were considered during the user studies: 1. the effectiveness of diverse tactile view types (output), 2. user input and exploration, and 3. the efficiency of specific interaction techniques. As a result, practical recommendations for implementing user interfaces on two-dimensional pin-matrix devices were given. These recommendations include ergonomic issues of physical devices as well as design considerations for textual and graphical content as well as orientation aids. In summary, the user studies showed that two-dimensional pin-matrix devices enable blind people an effective and efficient access to graphical user interfaces. Diverse tactile information visualizations can support users to fulfill various tasks. In general, two-dimensional interaction requires the extension of conventional exploration and input strategies of users. The provision of novel interaction techniques for supporting orientation can help to increase efficiency even more

Advances in mobile hardware and operating systems have made mobile a first-class development platform. Activities such as web browsing, casual game play, media playback, and document reading are now as common on mobile devices as on full-sized desktop systems. However, developers are still constrained by the inherent resource limitations of mobile devices. Unlike desktop systems, mobile devices must sacrifice performance to accomodate smaller form factors and battery-backed operation. Opportunistic offloading of computation from a mobile device to remote server infrastructure (i.e., "code offload") offers a promising way to overcome these constraints and to expand the set of applications

(i.e., "apps") that can run on devices.

Deciding to offload requires a careful consideration of the costs and benefits of a range of possible program partitions. This cost-benefit analysis depends on external factors, such as network conditions and the resources availability, as well as internal app properties, such as component dependencies, data representations, and code complexity. Thus, benefiting from offload requires some assistance from developers, but requiring developers to adopt arcane or unnatural programming models will hinder adoption of regardless of the potential benefits.

In this dissertation we characterize two frameworks that reduce the amount of developer effort required to improve the performance of mobile apps through code offload. The first, MAUI, is designed for computationally intensive general-purpose apps such as speech

and facial recognition. The second, Kahawai, is designed for graphics-intensive apps like fast-action video games.

MAUI continuously monitors the device, network, and app, and uses its measurements to compute an energy-efficient program partition. MAUI reduces the burden on developers by taking advantage of core features of the managed code environments common to mobile

platforms: code portability, serialization, reflection, and type safety. These features allows MAUI to automatically instrument and potentially offload methods that the developer has tagged as suitable for offload. MAUI is particularly effective on applications composed by operations whose computational cost is large compared to the transfer cost of their input parameters and their output results.

Kahawai is designed for graphics-intensive apps such as console-style games and takes advantage of two features of today's mobile gaming platforms: capable mobile GPUs and reusable game engines. Even though today's mobile devices cannot duplicate the sophisticated graphical detail provided by gaming consoles and high-end desktop GPUs, devices have seen rapid improvements in their GPU processing capabilities. Kahawai leverages a device's GPU to provide collaborative rendering. Collaborative rendering relies on a mobile GPU to generate low-fidelity output, which when combined with server-side GPU output allows a mobile device to display a high-fidelity result. The benefits of collaborative rendering are substantial: mobile clients can experience high-quality graphical output using relatively little bandwidth. Fortunately, because most modern games are built on top of reusable game engines, developers only have to identify the sources of non-determinism

in the game logic to take advantage collaborative rendering.

Together, MAUI and Kahawai demonstrate that code offload can provide substantial benefits for mobile apps without overburdening app developers.

Dissertation

Computing systems have become heterogeneous with the increasing prevalence of multi-core CPUs, Graphics Processing Units (GPU) and other accelerators in them. OpenCL has emerged as an attractive programming framework for heterogeneous systems. However, utilizing mul- tiple devices in OpenCL is a challenge as it requires the programmer to explicitly map data and computation to each device. Utilizing multiple devices simultaneously to speed up execu- tion of a kernel is even more complex, as the relative execution time of the kernel on different devices can vary significantly. Also, after each kernel execution, a coherent version of the data needs to be established. This means that, in order to utilize all devices effectively, the programmer has to spend considerable time and effort to distribute work across all devices, keep track of modified data in these devices and correctly perform a merging step to put the data together. Further, the relative performance of a program may vary across different inputs, which means a statically determined work distribution may not work well. In this work, we present FluidiCL, an OpenCL runtime that takes a program written for a single device and uses multiple heterogeneous devices to execute each kernel. The runtime performs dynamic work distribution and cooperatively executes each kernel on all available devices. Since we consider a setup with devices having discrete address spaces, our solution ensures that execution of OpenCL work-groups on devices is adjusted by taking into account the overheads for data management. The data transfers and data merging needed to ensure coherence are handled transparently without requiring any effort from the programmer. Flu- idiCL also does not require prior training or profiling and is completely portable across dif- ferent machines. Because it is dynamic, the runtime is able to adapt to system load. We have developed several optimizations for improving the performance of FluidiCL. We evaluate the runtime across different sets of devices. On a machine with an Intel quad-core processor and an NVidia Fermi GPU, FluidiCL shows a geomean speedup of nearly 64% over the GPU, 88% over the CPU and 14% over the best of the two devices in each benchmark. In all benchmarks, performance of our runtime comes to within 13% of the best of the two devices. FluidiCL shows similar results on a machine with a quad-core CPU and an NVidia Kepler GPU, with up to 26% speedup over the best of the two. We also present results considering an Intel Xeon Phi accelerator and a CPU and find that FluidiCL performs up to 45% faster than the best of the two devices. We extend FluidiCL from a CPU–GPU scenario to a three-device setup hav- ing a quad-core CPU, an NVidia Kepler GPU and an Intel Xeon Phi accelerator and find that FluidiCL obtains a geomean improvement of 6% in kernel execution time over the best of the three devices considered in each case.

Please read the abstract in the section, 00front, of this document
Dissertation (MA (AAC))--University of Pretoria, 2008.
Centre for Augmentative and Alternative Communication (CAAC)
unrestricted

The recent development of Virtual Reality technology, researchers are looking more into changing the way Virtual Reality is used in our daily lives in order to increase our productivity. One such application is the mapping of 3D spatial graphics in Computer Aided Design engineering where practitioners have been historically working on 3D models in a two dimensional environment. Researchers in Computer Graphics have proposed Virtual Reality as a more effective medium for CAD packages. This thesis carries out a user study to test whether or not 3D VR environments are more effective in relaying information to the users as compared to two dimensional displays such as computer screens by conducting a study to determine how users navigate and interact with complex CAD objects in the two different environments. The two environments make use of stereoscopic vision and monoscopic vision in order to compare the efficiency with which volunteers are able to notice subtle differences in objects. The motivation for this study stems from the fact that CAD in VR is largely an underdeveloped topic and the result of such a study could form a baseline and advocate for further research and development in this domain. The research question being addressed is “Does CAD in a three-dimensional Virtual Reality Environment(stereoscopic) allow for better understanding of shapes of complex assemblies as compared to CAD on two-dimensional (monoscopic) computer screens?” The findings of this study suggest that rather than just the display technique the kind of movements which objects undergo also contributes to the way users perceive the objects in 3D vs 2D spaces and uncover a set of directions which would be recommended for similar studies in the future.

This thesis presents the design for a novel haptic interface for large-format touchscreens. Techniques such as electrovibration, ultrasonic vibration, and external braked devices have been developed by other researchers to deliver haptic feedback to touchscreen users. However, these methods do not address the need for spatial constraints that only restrict user motion in the direction of the constraint. This technology gap contributes to the lack of haptic technology available for touchscreen-based upper-limb rehabilitation, despite the prevalent use of haptics in other forms of robotic rehabilitation. The goal of this thesis is to display kinesthetic haptic constraints to the touchscreen user in the form of boundaries and paths, which assist or challenge the user in interacting with the touchscreen. The presented prototype accomplishes this by steering a single wheel in contact with the display while remaining driven by the user. It employs a novel embedded force sensor, which it uses to measure the interaction force between the user and the touchscreen. The haptic response of the device is controlled using this force data to characterize user intent. The prototype can operate in a simulated free mode as well as simulate rigid and compliant obstacles and path constraints. A data architecture has been created to allow the prototype to be used as a peripheral add-on device which reacts to haptic environments created and modified on the touchscreen. The long-term goal of this work is to create a haptic system that enables a touchscreen-based rehabilitation platform for people with upper limb impairments.

This thesis presents kinematic templates, end-user drawing tools that influence the mouse cursor's movement within specific areas of a digital canvas. Two types of kinematic templates influence the cursor's movement: passive and active templates. Passive templates modify existing movement received from a pointing device to change the cursor's speed or direction of one's stroke. Active templates add movement to the cursor without movement from the pointing device. Since templates are provided as user-specified regions, these regions can be associated with areas of detail and they can be overlapped as a means of function composition. [¶] A kinematic template can be configured to improve upon one's freehand output without producing perfect output. Since templates do not necessarily prescribe geometric output, they constitute a visual composition aid that lies between unaided freehand drawing and drawing aids such as snapping constraints and perfect geometric primitives. [¶] Since kinematic templates can improve upon the consistency of one's strokes, it is beneficial for drawing visual styles such as hatching (an artistic effect that adds depth to a drawing with uniform strokes drawn in close proximity) and repetitive patterns. Since kinematic templates do not prescribe a type of output, one can "fight against" a template's preferred path of movement and discover unexpected, serendipitous outcomes.