The thesis is based on the use of mathematical modeling and analysis to gain insightinto the transmission dynamics of malaria in a community. A new deterministic model for assessing the role of age-structure on the disease dynamics is designed. The model undergoes backward bifurcation, a dynamic phenomenon characterized by the co-existence of a stable disease-free and an endemic equilibrium of the model when the associated reproduction number is less than unity. It is shown that adding age-structure to the basic model for malaria transmission does not alter its essential qualitative dynamics. The study is extended to incorporate the use of anti-malaria drugs. Numerical simulations of the extended model suggest that for the case when treatment does not cause drug resistance (and the reproduction number of each of the two strains exceed unity), the model undergoes competitive exclusion. The impact of various effectiveness levels of the treatment strategy is assessed.

An approach to quantitatively determine patient surface contours as part of an augmented reality (AR) system for patient position and posture correction was developed. Quantitative evaluation of the accuracy of patient positioning and posture correction requires the knowledge of coordinates of the patient contour. The system developed uses the surface contours from the planning CT data as the reference surface coordinates. The corresponding reference point cloud is displayed on screen to enable AR assisted patient positioning. A 3D computer vision system using structured light then captures the current 3D surface of the patient. The offset between the acquired surface and the reference surface, representing the desired patient position, is the alignment error. Two codification strategies, spatial encoding, and temporal encoding, were examined. Spatial encoding methods require a single static pattern to work, thus enabling dynamic scenes to be captured. Temporal encoding methods require a set of patterns to be successively projected onto the object, the encoding for each pixel is only complete when the entire series of patterns has been projected. The system was tested on a camera tracking object. The structured light reconstruction was accurate to within ±1 mm, ±1.5 mm, and ±4 mm in x, y, and z-directions (camera optical axis) respectively. The method was integrated into a simplified AR system and a visualization scheme based on z-direction offset was developed. A demonstration of how the final AR-3D vision hybrid system can be used in a clinical situation was given using an anatomical teaching phantom. The system and visualisation worked well and demonstrated the proof of principal of the approach. It was found that the achieved accuracy was not yet sufficient for clinical use. Further work on improving the projector calibration accuracy is required. Both the camera registration process and 3D computer vision using structured light have been shown to be capable of sub-millimeter accuracy on their own. If that level of accuracy can be reproduced in this system, the concept presented can potentially be used in Oncology departments as a cost-effective patient setup guidance system for external beam radiotherapy, used in addition to current laser/portal imaging/cone beam CT based setup procedures.

The objective of this thesis was to develop applications of monolithic fiber devices and actively controlled fibers. A special twin-core fiber known as a ‘Gemini’ fiber was used to construct equal arm-length fiber interferometers, impervious to temperature and mechanical perturbations. A broadband add/drop multiplexer was constructed by inscribing fiber Bragg gratings in the arms of a Gemini Mach-Zehnder interferometer. A broadband interferometric nanosecond switch was constructed from a micro-structured Gemini fiber with incorporated metal electrodes. Additionally, a Michelson fiber interferometer was built from an asymmetric twin-core fiber and used as a high-temperature sensor. While the device could be readily used to measure temperatures below 300 °C, an annealing process was required to extend the range up to 700 °C. The work included development, construction and evaluation of the components along with numerical simulations to estimate their behaviors and to understand the underlying processes. The thesis also explored the use of electrically controlled fibers for filtering in the microwave domain. An ultra-narrow phase-shifted fiber Bragg grating inscribed in a fiber with internal electrodes was used as a scanning filter to measure modulation frequencies applied to an optical carrier. A similar grating was used inside a dual-wavelength fiber laser cavity, to generated tunable microwave beat frequencies. The studied monolithic fiber interferometers and actively controlled fibers provide excellent building blocks in such varied field as in microwave photonics, telecommunications, sensors, and high-speed switching, and will allow for further applications in the future. / Syftet med denna avhandling var att utveckla tillämpningar av monolitiska fiber komponenter samt aktivt kontrollerbara fiber. En speciell tvillingkärnefiber, även kallad ’Geminifiber’ användes för att konstruera fiber interferometrar med identisk armlängd som ej påverkas av termiska och mekaniska variationer. En bredbanding utbytarmultiplexor konstruerades genom att skriva in fiber Bragg gitter inuti grenarna på en Gemini Mach-Zehnder interferometer. Geminifibrer med interna metallelektroder användes för att konstruera en bredbandig nanosekundsnabb interferometrisk fiberomkopplare. Därtill användes en tvillingkärnefiber som en hög-temperatursensor. Även om komponenten direkt kan användas upp till 300 °C, måste den värmebehandlas för att kunna användas upp till 700 °C. Arbetet har innefattat utveckling, konstruktion och utvärdering av komponenterna parallellt med numeriska simuleringar för att analysera deras beteenden samt få insikt om de underliggande fysikaliska processerna. Avhandlingen behandlar även tillämpningar av en elektriskt styrbar fiber för att filtrera radiofrekvenser. Ett ultrasmalt fasskiftat fiber Bragg gitter skrevs in i en fiber med interna elektroder och användes som ett svepande filter för att mäta modulationsfrekvensen på en optisk bärfrekvens. Ett liknande gitter användes inuti en laserkavitet för att generera två olika våglängder samtidigt. Dessa två våglängder användes sedan för att generera en svävningsfrekvens i mikrovågsbandet. De undersökta monolitiska fiberinterferometrarna och de aktivt styrbara fibrerna erbjuder en utmärkt byggsten inom så pass skiljda områden som Mikrovågsfotonik, Telekommunikation, Sensorer samt Höghastighets-omkopplare och bör kunna användas inom många olika tillämpningar i framtiden. / <p>QC 20130226</p>

Among the various approaches to 3-D imaging, structured light illumination (SLI) is widely spread. SLI employs a pair of digital projector and digital camera such that the correspondences can be found based upon the projecting and capturing of a group of designed light patterns. As an active sensing method, SLI is known for its robustness and high accuracy. In this dissertation, I study the phase shifting method (PSM), which is one of the most employed strategy in SLI. And, three novel approaches in PSM have been proposed in this dissertation. First, by regarding the design of patterns as placing points in an N-dimensional space, I take the phase measuring profilometry (PMP) as an example and propose the edge-pattern strategy which achieves maximum signal to noise ratio (SNR) for the projected patterns. Second, I develop a novel period information embedded pattern strategy for fast, reliable 3-D data acquisition and reconstruction. The proposed period coded phase shifting strategy removes the depth ambiguity associated with traditional phase shifting patterns without reducing phase accuracy or increasing the number of projected patterns. Thus, it can be employed for high accuracy realtime 3-D system. Then, I propose a hybrid approach for high quality 3-D reconstructions with only a small number of illumination patterns by maximizing the use of correspondence information from the phase, texture, and modulation data derived from multi-view, PMP-based, SLI images, without rigorously synchronizing the cameras and projectors and calibrating the device gammas. Experimental results demonstrate the advantages of the proposed novel strategies for 3-D SLI systems.

The use of structured light illumination techniques for three-dimensional data acquisition is, in many cases, limited to stationary subjects due to the multiple pattern projections needed for depth analysis. Traditional Composite Pattern (CP) multiplexing utilizes sinusoidal modulation of individual projection patterns to allow numerous patterns to be combined into a single image. However, due to demodulation artifacts, it is often difficult to accurately recover the subject surface contour information. On the other hand, if one were to project an image consisting of many thin, identical stripes onto the surface, one could, by isolating each stripe center, recreate a very accurate representation of surface contour. But in this case, recovery of depth information via triangulation would be quite difficult. The method described herein, Modified Composite Pattern (MCP), is a conjunction of these two concepts. Combining a traditional Composite Pattern multiplexed projection image with a pattern of thin stripes allows for accurate surface representation combined with non-ambiguous identification of projection pattern elements. In this way, it is possible to recover surface depth characteristics using only a single structured light projection. The technique described utilizes a binary structured light projection sequence (consisting of four unique images) modulated according to Composite Pattern methodology. A stripe pattern overlay is then applied to the pattern. Upon projection and imaging of the subject surface, the stripe pattern is isolated, and the composite pattern information demodulated and recovered, allowing for 3D surface representation. In this research, the MCP technique is considered specifically in the context of a Hidden Markov Process Model. Updated processing methodologies explained herein make use of the Viterbi algorithm for the purpose of optimal analysis of MCP encoded images. Additionally, we techniques are introduced which, when implemented, allow fully automated processing of the Modified Composite Pattern image.

As a critical step after the discovery of material culture in the field, archaeologists have a need to document these findings with a slew of different physical measurements and photographs from varying perspectives. 3-D imaging is becoming increasingly popular as the primary documenting method to replace the plethora of tests and measurements, but for remote areas 3-D becomes more cumbersome due to physical and environmental constraints. The difficulty of using a 3-D imaging system in such environments is drastically lessened while using the RAHAS technique, since it acquires scans untethered to a computer. The goal of this thesis is to present the RAHAS Structured Light Illumination technique for 3-D image acquisition, and the performance of the RAHAS technique as a measurement tool for documentation of material culture on a field trip to the Rio Platano Biosphere in Honduras.

Fingerprints are the most accurate and widely used biometrics for human identification due to their uniqueness, rapid and easy means of acquisition. Contact based techniques of fingerprint acquisition like traditional ink and live scan methods are not user friendly, reduce capture area and cause deformation of fingerprint features. Also, improper skin conditions and worn friction ridges lead to poor quality fingerprints. A non-contact, high resolution, high speed scanning system has been developed to acquire a 3D scan of a finger using structured light illumination technique. The 3D scanner system consists of three cameras and a projector, with each camera producing a 3D scan of the finger. By merging the 3D scans obtained from the three cameras a nail to nail fingerprint scan is obtained. However, the scans from the cameras do not merge perfectly. The main objective of this thesis is to calibrate the system well such that 3D scans obtained from the three cameras merge or align automatically. This error in merging is reduced by compensating for radial distortion present in the projector of the scanner system. The error in merging after radial distortion correction is then measured using the projector coordinates of the scanner system.

This research focuses on evaluating and enhancing the performance of an in-house, structured, 2D CFD code - GHOST, on modern commodity clusters. The basic philosophy of this work is to optimize the cache performance of the code by splitting up the grid into smaller blocks and carrying out the required calculations on these smaller blocks. This in turn leads to enhanced code performance on commodity clusters. Accordingly, this work presents a discussion along with a detailed description of two techniques: external and internal blocking, for data access optimization. These techniques have been tested on steady, unsteady, laminar, and turbulent test cases and the results are presented. The critical hardware parameters which influenced the code performance were identified. A detailed study investigating the effect of these parameters on the code performance was conducted and the results are presented. The modified version of the code was also ported to the current state-of-art architectures with successful results.

Detection of malingering is a significant concern in forensic psychological assessments. The best-validated tests currently available are time-intensive for both test-takers and mental health professionals. Thus, well-validated, brief screening measures for malingering would be useful in a forensic environment. The Structured Inventory of Malingered Symptomatology (SIMS; Smith andamp; Burger, 1997) has demonstrated potential in this role. The present study attempts replication of previous studies while extending validation from analogue and male criminal forensic samples to both men and women in a civil forensic setting. The SIMS accuracy in the detection of both neurocognitive and psychiatric symptom feigning is evaluated by comparing its performance to stringent multi-scale criterion measures in a large forensic sample. Cut scores suggested by previous studies yield high sensitivity and negative predictive power in this sample when the SIMS is used to detect psychiatric symptom malingering; however, these cut scores perform inadequately here when screening for the feigning of neurocognitive impairment, and no alternative cut score functions well in this capacity. The results lend support to the utility of the SIMS as a screen for psychiatric symptom malingering by men and women in a civil forensic setting.

Nano structured solar cells provide an opportunity for increased open circuit voltages and and short circuit currents in solar cells due to quantum confinement of the window and absorber materials and an increase in the optical path length for the incident light. In this study, both bulk and nano heterojunctions of CIS/CdS and Cu2S/CdS devices have been fabricated and studied on plain glass substrates and inside porous alumina templates to compare their performance. The devices have also been characterized SEM, XRD and JV measurements. The J-V curves have also been analyzed for series resistance, diode ideality factor and reverse saturation current density.