Diclofenac (DCF) and other emerging contaminants have been found in environments worldwide. These contaminants may enter the environment due to the application of treated wastewater, biosolids and direct excrement related to veterinary application. Leakage from the soils toward the groundwater is largely controlled by sorption and microbial degradation. Most studies on the environmental fate of DCF have focused on degradation during wastewater treatment processes. However, little is known about their behavior in soil. In this study, the combined effect of adsorption and degradation of diclofenac has been investigated in four (4) 24 ft3 agricultural soil-filled beds designed to mimic natural vegetated soil environments, enhanced via controlled wetting and drying cycles. Contour bund installation on slopes of 5, 10, 15 and 20° were mimicked in the beds. Results showed that the soil environment was a strong inhibitor to the leaching of DCF through the soil. Saturating slopes via contour bund application however can lead to landslides that may impact structures and human life. A feasible contour bund installation site was investigated and found that 20° slopes under saturated conditions resulted in an unsafe factor of safety and is not encouraged as a solution for stormwater management. The effect of contour bund application on slopes under 15° at the installation site can potentially increase removal of emerging contaminants, thereby protecting groundwater resources without endangering life or property.

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Understanding machine vision can certainly improve our understanding of artificial intelligence as vision happens to be one of the basic intellectual activities of living beings. Since the notion of computation unifies the concept of a machine, computer vision can be understood as an application of modern approaches for achieving artificial intelligence, like machine learning and cognitive psychology. Computer vision mainly involves processing of different types of sensor data resulting in "perception of machines". Perception of machines plays a very important role in several artificial intelligence applications with sensors. There are numerous practical situations where we acquire sensor data for e.g. from mobile robots, security cameras, service and recreational robots. Making sense of this sensor data is very important so that we have increased automation in using the data. Tools from image processing, shape analysis and probabilistic inferences i.e. learning theory form the artillery for current generation of computer vision researchers. In my thesis I will address some of the most annoying components of two important open problems viz. object recognition and autonomous navigation that remain central in robotic, or in other words computational, intelligence. These problems are concerned with inducing computers, the abilities to recognize and navigate similar to those of humans. Object boundaries are very useful descriptors for recognizing objects. Extracting boundaries from real images has been a notoriously open problem for several decades in the vision community. In the first part I will present novel techniques for extracting object boundaries. The techniques are based on practically successful state-of-the-art Bayesian filtering framework, well founded geometric properties relating boundaries and skeletons and robust high-level shape analyses Acquiring global maps of the environments is crucial for robots to localize and be able to navigate autonomously. Though there has been a lot of progress in achieving autonomous mobility, for e.g. as in DARPA grand-challenges of 2005 and 2007, the mapping problem itself remains to be unsolved which is essential for robust autonomy in hard cases like rescue arenas and collaborative exploration. In the second part I will present techniques for merging maps acquired by multiple and single robots. We developed physics-based energy minimization techniques and also shape based techniques for scalable merging of maps. Our shape based techniques are a product of combining of high-level vision techniques that exploit similarities among maps and strong statistical methods that can handle uncertainties in Bayesian sense. / Computer and Information Science

Dynamically recrystallized quartz microstructures preserved in contact aureoles allow for stress and strain rate estimates associated with penetrative deformation of rocks surrounding pluton margins. Microstructural analysis of the Harkless quartzites surrounding the western margin of Papoose Flat pluton indicates that recrystallization occurred by grain boundary migration with mean recrystallized grain size ranging from 86-225 µm. The application of three calibrated piezometers results in differential stress estimates between ~11 and ~29 MPa. Published wet-quartzite dislocation creep flow laws combined with deformation temperature, water fugacity, and differential stress estimates infer strain rates that range from 1.2 x 10⁻¹⁴ s⁻¹ to 2.3 x 10⁻¹² s⁻¹. In order to analyze 3D subsurface fault geometry along map-pattern curves (salients and recesses), a structure contour map of the Moine thrust, extending from the North Coast southwards to the Dundonnel area, was constructed from 1:50,000 scale British Geological Survey (BGS) maps by correlating between elevation control points constrained by the intersection of the fault trace with topographic contours. The structure contour map indicates significant lateral variation in fault geometry along the Moine thrust, with recesses associated with antiformal corrugations in the subsurface and salients characterized by planar geometries or broad synformal corrugations. Additionally, structure contour maps constructed on the Glencoul thrust, as depicted by original BGS maps confirms that the thrust segments to the NE and SW of Loch Glencoul are part of the same structure, rather than different structures separated by a lateral ramp as shown on more recent BGS maps. / Master of Science

The rapid, accurate determination of the positions and strengths of sources of dangerous radioactivity takes high priority after a catastrophic event to ensure the safety of personnel, civilians, and emergency responders. This thesis presents approaches and algorithms to autonomously investigate radioactive material using an unmanned aerial vehicle. Performing this autonomous analysis comprises five major steps: ingress from a base of operations to the danger zone, initial detection of radioactive material, measurement of the strength of radioactive emissions, analysis of the data to provide position and intensity estimates, and finally egress from the area of interest back to the launch site. In all five steps, time is of critical importance: faster responses promise potentially saved lives. A time-optimal ingress and egress path planning method solves the first and last steps. Vehicle capabilities and instrument sensitivity inform the development of an efficient search path within the area of interest. Two algorithms—a grid-based recursive Bayesian estimator and a novel radiation contour analysis method—are presented to estimate the position of radioactive sources using simple gross gamma ray event count data from a nondirectional radiation detector. The latter procedure also correctly estimates the number of sources present and their intensities. Ultimately, a complete unsupervised mission is developed, requiring minimal initial operator interaction, that provides accurate characterization of the radiation environment of an area of interest as quickly as reasonably possible. / Master of Science

Yes / Purpose Flicker-defined form (FDF) stimuli have recently been adopted for visual field testing. A key difference between FDF and traditional perimetric stimuli is that the entire display background contains flickering dots. The purpose of this study was to determine whether the perception of FDF stimuli is influenced by lateral interactions involving regions beyond the stimulus border in young healthy observers. Methods Experiment 1 measured the effect of surround size and retinal eccentricity on the detection of the FDF contour. Psychometric functions were collected for surround diameters of 20°, 30° and 40°, and with stimuli centred at eccentricities of 0°, 10° and 20°. Experiment 2 measured the effect of target-surround temporal phase difference on apparent temporal contrast (flicker strength) of the target for both the FDF stimulus and a solid-field stimulus. Psychometric functions were collected for target-surround phase differences of 0°, 45°, 90°, 135° and 180°. Results Our results show a mild surround-suppression effect for FDF stimuli that is independent of surround size. Magnitudes of FDF surround suppression were consistent with the reduced temporal contrast energy of the stimulus compared to solid-field stimuli. Conclusion FDF stimuli necessarily have both flickering target and background. Our results suggest that visual field defects outside the target are unlikely to markedly influence the detection and perception of the FDF stimulus. Nevertheless, mild surround suppression of contrast arises for FDF stimuli, hence interactions between the background and the target area may influence FDF results in conditions that alter centre-surround perceptual effects.

The book is a series of plates, pictures and writings which are the results of an architectural thesis exploring, line, contour and layers. The plates are scans of original work by the author, made in a combination of media including: pencil, pastel, watercolor, photograph, study models, hand-drafted drawings, and computer aided drawings. A transcript of the presentation of the work at the thesis defense is included. The simple idea is the impression of contour by the expression of layers. The contour is a line tracing the motion and movement of architecture. Resulting from practice in drawing using pastels, pencil and paper the line, through continuity, can twist, pass over, go under and around- joining parts into an organized whole. Following a program of a modern bath, an architectural space is made, built by layers. The thesis is an architectural exploration of layers and the resultant contours. The best representation of this work is available in printed form at the Art and Architecture Library on the Virginia Tech campus in Blacksburg, Virginia. / Master of Architecture

This exploratory study aims to elucidate the mental processes of wayfinding in an outdoor area and the effects of map contour representations, map color, individual differences of users (gender, brain dominance, experience level, and cultural differences), and environmental cues using a field study in an established trail network in Jefferson National Forest. Six maps with three different contour representations (contour lines, shaded relief, and schematic) and two color codes (color and black-and-white) were tested for wayfinding performance. Thirty-six participants of different nationalities (Locals versus Internationals), experience in map usage (experienced versus novice), handedness, and gender took part in the study. Three out of ten junctions on the test route had directional signs while the rest had no sign. The participants performed wayfinding tasks in a national forest trail park, using the think aloud and retrospective protocols to obtain the information processes used by the participants during wayfinding. Subjective feedback was also obtained to find out users' map preferences and opinions on their experience during the experiment. Multiple regression analyses were used to predict the relationship of the predictor variables to wayfinding performance. It was found that cultural differences and signage presence were significant predictors of decision-making accuracy at trail junctions. The rest of the predictors were not significant in predicting total time of completion, time for decision-making at junction, accuracy of decision-making, and time deviated from route due to choosing a wrong path at junction. Cultural differences were also significant in the prediction of the time deviated from route. It was also found that the participants were using maps to derived route information for wayfinding. They utilized structural matching of the map with the terrain, by orientation principle, to continuously check the current position on the map. There was some evidence of participants gaining survey knowledge from the map during wayfinding but this could not be confirmed by the study. A set of design guidelines were given for map and trail design to improve the wayfinding performance of recreational users. / Master of Science