<p>The company where this thesis was formulated constructs VR applications for the medical environment. The hardware used is ordinary dektops with consumer level graphics cards and haptic devices. In medicin some operations require microscopes or cameras. In order to simulate these in a virtual reality environment for educational purposes, the effect of depth of field or focus have to be considered. </p><p>A working algorithm that generates this optical occurence in realtime, stereo rendered computer graphics is presented in this thesis. The algorithm is implemented in OpenGL and C++ to later be combined with a VR application simulating eye-surgery which is built with OpenGL Optimizer. </p><p>Several different approaches are described in this report. The call for realtime stereo rendering (~60 fps) means taking advantage of the graphics hardware to a great extent. In OpenGL this means using the extensions to a specific graphic chip for better performance, in this case the algorithm is implemented for a GeForce3 card. </p><p>To increase the speed of the algorithm much of the workload is moved from the CPU to the GPU (Graphics Processing Unit). By re-defining parts of the ordinary OpenGL pipeline via vertex programs, a distance-from-focus map can be stored in the alpha channel of the final image with little time loss. </p><p>This can effectively be used to blend a previously blurred version of the scene with a normal render. Different techniques to quickly blur a renderedimage is discussed, to keep the speed up solutions that require moving data from the graphics card is not an option.</p>

<p> </p><p>Post-processing techniques are used to change a rendered image as a last step before presentation and include, but is not limited to, operations such as change of saturation or contrast, and also more advanced effects like depth-of-field and tone mapping.</p><p>Depth-of-field effects are created by changing the focus in an image; the parts close to the focus point are perfectly sharp while the rest of the image has a variable amount of blurriness. The effect is widely used in photography and movies as a depth cue but has in the latest years also been introduced into computer games.</p><p>Today’s graphics hardware gives new possibilities when it comes to computation capacity. Shaders and GPGPU languages can be used to do massive parallel operations on graphics hardware and are well suited for game developers.</p><p>This thesis presents the theoretical background of some of the recent and most valuable depth-of-field algorithms and describes the implementation of various solutions in the shader domain but also using GPGPU techniques. The main objective is to analyze various depth-of-field approaches and look at their visual quality and how the methods scale performance wise when using different techniques.</p><p> </p>

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 174-179). Also available via the Internet

Automatically recognizing classifier-based grammatical structures of American Sign Language (ASL) is a challenging problem. Classifiers in ASL utilize surrogate hand shapes for people or "classes" of objects and provide information about their location, movement and appearance. In the past researchers have focused on recognition of finger spelling, isolated signs, facial expressions and interrogative words like WH-questions (e.g. Who, What, Where, and When). Challenging problems such as recognition of ASL sentences and classifier-based grammatical structures remain relatively unexplored in the field of ASL recognition.  One application of recognition of classifiers is toward creating educational games to help young deaf children acquire language skills. Previous work developed CopyCat, an educational ASL game that requires children to engage in a progressively more difficult expressive signing task as they advance through the game.   We have shown that by leveraging context we can use verification, in place of recognition, to boost machine performance for determining if the signed responses in an expressive signing task, like in the CopyCat game, are correct or incorrect. We have demonstrated that the quality of a machine verifier's ability to identify the boundary of the signs can be improved by using a novel two-pass technique that combines signed input in both forward and reverse directions. Additionally, we have shown that we can reduce CopyCat's dependency on custom manufactured hardware by using an off-the-shelf Microsoft Kinect depth camera to achieve similar verification performance. Finally, we show how we can extend our ability to recognize sign language by leveraging depth maps to develop a method using improved hand detection and hand shape classification to recognize selected classifier-based grammatical structures of ASL.

As humans, we have evolved to see in three dimensions. Our ancestors developed two eyes that only look forward, which allows the visual area that can perceive depth to be most of the field of view. A variety of sensors have been developed which can determine depth in the environment. They range from producing individual points of depth to the depth of everything in the environment. These sensors have become cheap and can now reliably produce accurate depth. Research is needed to determine how to present the proximity information to the people using the sensors. Touch, sound, and vision have all been used to provide depth information to the users. This research focuses on vision and compares methods of visually presenting proximity information to a user. The methods examined are stereovision and false color visual proximity mapping. False color mapping proved most effective while, surprisingly, stereovision was not helpful.

USF completed a research study in 2005, which prioritized the replacement of 85 deteriorating composite precast deck panel bridges. This thesis re-evaluates the original recommendations in the wake of failures of two of these bridges in 2007. Since funding will not allow all identified bridges to be replaced, it was necessary to determine the most effective repair methods. To assess USF’s recommendations, a forensic study was undertaken in which the most current inspection and work program documents on the two failed bridges were reviewed and FDOT personnel interviewed. The best repair procedures were determined by reviewing repair plans, specifications, reports and site visits. The study found the two bridges that failed had been correctly prioritized by USF (No. 1 of 18 and No. 8 of 15). A new, accelerated repair method encompassing complete bay replacement was developed in a pilot project funded by the Florida Department of Transportation.

Abstract This project illustrates the use of the human's ability to balance according to his center of gravity as demonstrated in two applications. The center of gravity of a human is explained in detail in order to use it in controlling the Aldebaran NAO robot and in the robot-assisted balance training. The first application explains how a humanoid robot can mimic a human's movements via a three dimensional depth sensor where the sensor analyzes the position of a user's limbs and how the robot can lift one foot and balance on the other by redistributing the its body mass when the user lifts his foot. The results showed that this algorithm enabled NAO to successfully mimic the users' arms, and was able to balance on one foot by repositioning its center of mass. The second application investigates how individuals with stroke lean when undergoing robot-assisted balance training. In some instances, they can develop inappropriate leaning behaviors during the training. The Kinect sensor is used to assist in optimizing patients' results by integrating it with the training program. The results showed that the Kinect sensor can improve the efficiency of the process by giving users graphical information about their mass distribution and whether they are leaning correctly or not.

Coral habitats span the range from tropical to polar, extremely shallow to thousands of meters deep. The differences in light and temperature experienced in these varied habitats likely affect the metabolic rates of the corals residing there. The metabolism of three coral species from different habitats have been examined to elucidate the effects of these environmental parameters on metabolism, an under-studied aspect of coral biology. For all three species, measurements of oxygen uptake, ammonium excretion, and activity of the enzymes lactate dehydrogenase (LDH), malate dehydrogenase (MDH), and citrate synthase (CS) were used to characterize their metabolism. Off Florida's Gulf coast, Cladocora arbuscula is known to be one of the species least damaged by bleaching events and is one of the quickest to recover, making it an ideal candidate for studying the effects of symbionts. The first set of experiments was designed to reveal the effect of disrupting the coral-algal symbiosis between this subtropical shallow-water coral and its dinoflagellate symbiont, Symbiodinium. The metabolic effects were described for "normal" C. arbuscula and those "bleached" by being held in total darkness for 4 months. Normal C. arbuscula had a relatively low rate of oxygen consumption at 21°C, averaging 2.43±0.65 µmol O2 gwm-1 h-1 (±S.E.), using tissue wet mass, while the bleached colonies had an average rate of 2.46±0.49 µmol O2 gwm-1 h-1. Ammonium excretion averaged 0.07±0.02 and 0.10±0.03 µmol NH4+ gwm-1 h-1 (±S.E.) for normal and bleached C. arbuscula, respectively. The activity values of the metabolic enzymes citrate synthase (CS) fell within the normal range expected for a cnidarian, averaging around 0.09±0.02 activity units (U) gwm-1 for both treatments, indicating normal aerobic ability. MDH was extremely high for the normal corals, compared to other cnidarians, averaging 2.5±0.4 U gwm-1, and a bit lower for the bleached corals, averaging 1.2±0.3 U gwm-1, indicating high MDH activity during both normoxia and hypoxia. LDH activity, also high, averaged 1.3±0.2 U gwm-1 for both treatments, indicating anaerobic competence. These experiments show that C. arbuscula is adept at maintaining almost completely normal metabolic function when bleached, although the corals quickly become re-inoculated with symbionts upon return to normal light conditions in a tank with normal corals. The second set of experiments served to characterize the metabolism of Lophelia pertusa, an azooxanthellate cold-water coral that thrives in water depths between 36 and 3383 m. L. pertusa is rather stenothermal, commonly found between 6-8°C, but in the Gulf of Mexico can be subjected to warm water incursions. This makes it an ideal candidate for the examination of the effects of temperature. L. pertusa exhibited a respiration rate of 1.14 µmol O2 gwm-1 h-1 at the control temperature of 8°C. Calculating the Q10 for bringing L. pertusa up to the environmental temperature of C. arbuscula results in a value of 1.8. The 11°C treatment group exhibited an 11% increase in respiration, while at 13°C, the corals showed a 23% rise from normal. The 5°C group showed a 32% decrease in respiration. The activity values of the metabolic enzyme citrate synthase (CS) fell into the normal range expected for a cnidarian, averaging 0.15, 0.20, 0.10, and 0.18 activity units (U) gwm-1 for the 8°C, 11°C, 13°C, and 5°C treatments, respectively. Malate dehydrogenase (MDH) values were unexpectedly high, averaging 2.05, 1.48, 1.48, and 1.82U gwm-1 for the 8°C, 11°C, 13°C, and 5°C treatments, respectively. Lactate dehydrogenase (LDH) was undetectable in this species, suggesting it has a different terminal glycolytic enzyme. Nonetheless, the other two enzymes indicate metabolic competence in both normoxic and hypoxic conditions. L. pertusa is adaptable to temperatures within its range, although its respiration rate is lower than that of tropical corals. The third set of experiments characterized the metabolism of the endemic Antarctic coral Flabellum impensum, one of the world's largest solitary corals. It resides at roughly the same depths as L. pertusa, but the water temperature in its habitat never strays far from 0°C. F. impensum had a low rate of oxygen consumption at 0°C, averaging 0.31 µmol O2 g-1 h-1, calculated using tissue wet mass. Calculating a Q10 for this species at C. arbuscula's habitat temperature results in a value of 2.7. Ammonium excretion averaged 4.21 nmol NH4+ gwm-1 h-1. The activity values of the metabolic enzymes citrate synthase (CS), malate dehydrogenase (MDH), and lactate dehydrogenase (LDH) fell within the normal range expected for a cnidarian, averaging 0.13, 1.01, and 0.42 activity units (U) gwm-1, respectively. A count of the skeletal growth bands on the calyx suggests that this species has a linear extension rate of approximately 1 mm per year. F. impensum is a long-lived, slow-growing coral, with a low metabolic rate.

Collective case study (Creswell, 2014; Stake, 1995) was used to explore the journey of coach-athlete dyads who were able to successfully maintain their training and interpersonal relationships throughout the course of the athlete enduring a mental block. Three coach-athlete dyads, plus one additional athlete, completed in-depth one-on-one interviews, discussing their coach-athlete relationship before, during, and after the mental block. All dyads were same sex, nationally ranked coach-athlete pairs, from sports involving mandatory elements that include both twisting and flipping components. Categorical aggregation of participant statements lead to the formation of five main themes associated with dyads successfully overcoming a mental block (where success was defined as the athlete regaining the ability to perform the skill that they had previously been unable to do on account of the mental block and the dyad maintaining their training and interpersonal relationship): 1) Get to Know Your Athlete: The Need for High Quality Communication; 2) Be a United Front; 3) Mistakes and Miscommunications Happen: Recovery is Key; 4) Seek Outside Resources; 5) Be Patient. Results suggest that an environment for success can flourish when each party is open, honest, and self-aware of their own limitations. It is suggested that future research utilize the 3 + 1Cs Model of the coach-athlete relationship in exploring how dyads can successfully overcome a mental block.

Polymeric waveguide-on-flex has the potential to replace complex and costly light-turning devices in optoelectronic applications. As light signals are propagated and confined through the definition of core-cladding interface, the light guiding structure is required to adhere well and ensure long term interfacial stability. This thesis addresses the gap that has emerged in the fundamental material issues such as the polymeric optical waveguide materials deposited on the flexible substrates. In addition, this thesis investigates the feasibility of a new approach using electrostatic-induced lithography in micro-patterning of polymer, in optical waveguide fabrication. Plasma treatment is applied to enhance interfacial adhesion between flex substrates and optical cladding layers. The modified flex surfaces of polyimide KaptonHNTM and liquid crystal polymer VecstarTM materials are characterised. In addition, sonochemical surface treatment is evaluated on these flexible substrates. ToF-SIMS depth profiling has confirmed the interface reaction mechanisms where it has shown that plasma treatment increases the interfacial interpenetration. The larger interfacial width increases the possible entanglement mechanism between the polymer chains. These results, together with the double cantilever beam testing, indicate the strengthening of the polymeric interface upon plasma treatment, which is essential for long term optical and mechanical stability of waveguide-on-flex applications. A new method of micro-pattering of polymer material has been adopted for fabricating multimode waveguide-on-flex. The method, using an electrostatic-induced lithography, is developed to produce 50 μm x 50 μm arrays of polysiloxane LightlinkTM waveguide on flex. This thesis looks at various process recipes of the technique and reports the pattern formation of polymeric optical core. By adjusting the spin-coated liquid core thickness, pre-bake condition, UV exposure and applied voltage, the aspect ratio and profile of the optical core microstructure can be varied. As the electrostatic pressure overcoming the surface tension of spin-coated waveguide material induces the optical core formation, the core structure is smooth, making it ideal for low scattering loss waveguide. The propagation loss of fabricated waveguide is measured at 1.97 dB/cm at 850 nm wavelength. The result shows that the use of electrostatic-induced lithography in optical polymer is a promising approach for low cost and low temperature (<150 °C) processing at back end optical-electrical integrated circuitry assembly.