Unsteady aerodynamic theories are essential in the analysis of bird and insect flight. The study of these types of locomotion is vital in the development of flapping wing aircraft. This paper uses potential flow aerodynamics to extend the unsteady aerodynamic theory of Theodorsen and Garrick (which is restricted to rigid airfoil motion) to deformable thin airfoils. Frequency-domain lift, pitching moment and thrust expressions are derived for an airfoil undergoing harmonic oscillations and deformation in the form of Chebychev polynomials. The results are validated against the time-domain unsteady aerodynamic theory of Peters. A case study is presented which analyzes several combinations of airfoil motion at different phases and identifies various possibilities for thrust generation using a deformable airfoil. / Master of Science

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Object localization refers to the detection, matching and segmentation of objects in images. The localization model presented in this paper relies on deformable templates to match objects based on shape alone. The shape structure is captured by a prototype template consisting of hand-drawn edges and contours representing the object to be localized. A multistage, multiresolution algorithm is utilized to reduce the computational intensity of the search. The first stage reduces the physical search space dimensions using correlation to determine the regions of interest where a match it likely to occur. The second stage finds approximate matches between the template and target image at progressively finer resolutions, by attracting the template to salient image features using Edge Potential Fields. The third stage entails the use of evolutionary optimization to determine control point placement for a Local Weighted Mean warp, which deforms the template to fit the object boundaries. Results are presented for a number of applications, showing the successful localization of various objects. The algorithm’s invariance to rotation, scale, translation and moderate shape variation of the target objects is clearly illustrated.

This thesis presents a new method for the controllable damping of deformable objects. The method evolves from physically based techniques; however, it allows for non-physical, but visually plausible motion. This flexibility leads to a simple interface, with intuitive control over the behaviour of the material. This method is particularly suited for strongly damped materials, which account for the majority of objects of interest to animation, since it produces non-oscillatory behaviour. This is similar to critical damping, except that it affects all modes independently. The new method is based on the minimization of a slightly modified version of total energy. This framework can be used to simulate many other physical phenomena, and therefore lends itself to coupling with other simulations. Implementation details for a simple example are given. Results are shown for varying parameters and compared to those produced by a traditional method.

This thesis presents a new method for the controllable damping of deformable objects. The method evolves from physically based techniques; however, it allows for non-physical, but visually plausible motion. This flexibility leads to a simple interface, with intuitive control over the behaviour of the material. This method is particularly suited for strongly damped materials, which account for the majority of objects of interest to animation, since it produces non-oscillatory behaviour. This is similar to critical damping, except that it affects all modes independently. The new method is based on the minimization of a slightly modified version of total energy. This framework can be used to simulate many other physical phenomena, and therefore lends itself to coupling with other simulations. Implementation details for a simple example are given. Results are shown for varying parameters and compared to those produced by a traditional method.

This thesis presents a new method for the controllable damping of deformable objects. The method evolves from physically based techniques; however, it allows for non-physical, but visually plausible motion. This flexibility leads to a simple interface, with intuitive control over the behaviour of the material. This method is particularly suited for strongly damped materials, which account for the majority of objects of interest to animation, since it produces non-oscillatory behaviour. This is similar to critical damping, except that it affects all modes independently. The new method is based on the minimization of a slightly modified version of total energy. This framework can be used to simulate many other physical phenomena, and therefore lends itself to coupling with other simulations. Implementation details for a simple example are given. Results are shown for varying parameters and compared to those produced by a traditional method. / Science, Faculty of / Computer Science, Department of / Graduate

Deformable mirrors (DMs) are needed in optical systems for compensation of aberrations using a control technique known as adaptive optics (AO). DMs are generally comprised of a mirror face sheet supported by an array of underlying actuators that can shape the face sheet with nanometer-scale precision. A challenge in fabrication of such devices is that the adhesive assembly process that is generally used to attach surface-normal actuators to the face sheet results in undesirable stress and strain, leading to uncorrectable deformation of the face sheet. The work described in this dissertation presents an innovative mechanical design that effectively solves that problem. The dissertation details design, fabrication, assembly, and control of an electromagnetically actuated DM comprised of a bulk-micromachined single crystal silicon face sheet, an array of single crystal silicon posts that are integrally attached to the face sheet, and an electromagnetic actuation system. Actuation is achieved using an array of fixed permanent magnets adhesively attached to the distal ends of the posts, which are attracted to or repelled by an array of fixed electromagnetic coils, each of which can be independently controlled. An analysis of the stress-reducing mechanical design for DM assembly is described, along with simulations and experimental results. The approach entails a direct application of St. Venant’s Principle to transform the complex and elevated stress state at the adhesion interface between magnet and post to a smaller and simpler and stress state at the face sheet, resulting in more than an order of magnitude reduction in stress-induced deformation. Two electro-magnetic actuation approaches were explored. The first uses a surface micromachined and then electroplated planar copper coil array, while the second uses an array of three-dimensional coils made from precision wound copper wire, assembled in an aluminum housing. Multiple DMs based on these designs were produced in a design and assembly process that precisely attached magnets to posts, aligned that subassembly with the actuator array, and controlled the gap between the magnets and the actuation coils. An electronic driver circuit was developed to control the actuator array using a commercial DM driver and a custom designed voltage-to-current amplifier array. Measurements of static and dynamic performance of the DM in response to actuation were made using a partitioned aperture wavefront (PAW) surface mapping microscope and a high bandwidth single point fiber-optical displacement probe. The prototype DMs had 19 actuators spaced 1.5 mm apart, supporting a 12 mm diameter, 10 µm thick face sheet. Actuation of up to +/-10 µm was achieved and dynamic performance was evaluated. This new DM design and shows promise in applications of optical aberration correction and high-power laser beamforming. / 2025-05-23T00:00:00Z

Deformable image registration (DIR) is a type of registration that calculates a deformable vector field (DVF) between two image data sets and permits contour and dose propagation. However the calculation of a DVF is considered an ill-posed problem, as there is no exact solution to a deformation problem, therefore all DVFs calculated contain errors. As a result it is important to evaluate and assess the accuracy and limitations of any DIR algorithm intended for clinical use. The influence of image quality on the DIR algorithms performance was also evaluated. The hybrid DIR algorithm in RayStation 4.0.1.4 was assessed using a number of evaluation methods and data. The evaluation methods were point of interest (POI) propagation, contour propagation and dose measurements. The data types used were phantom and patient data. A number of metrics were used for quantitative analysis and visual inspection was used for qualitative analysis. The quantitative and qualitative results indicated that all DVFs calculated by the DIR algorithm contained errors which translated into errors in the propagated contours and propagated dose. The results showed that the errors were largest for small contour volumes (<20cm3) and for large anatomical volume changes between the image sets, which pushes the algorithms ability to deform, a significant decrease in accuracy was observed for anatomical volume changes of greater than 10%. When the propagated contours in the head and neck were used for planning the errors in the DVF were found to cause under dosing to the target tumour by up to 32% and over dosing to the organs at risk (OAR) by up to 12% which is clinically significant. The results also indicated that the image quality does not have a significant effect on the DIR algorithms calculations. Dose measurements indicated errors in the DVF calculations that could potentially be clinically significant. The results indicate that contour propagation and dose propagation must be used with caution if clinical use is intended. For clinical use contour propagation requires evaluation of every propagated contour by an expert user and dose propagation requires thorough evaluation of the DVF.

Segundo a definição original de MCINERNEY & TERZOPOULOS (1995), modelos deformáveis são curvas ou superfícies formadas por pontos conectados que simulam corpos elásticos. Por superarem muitas limitações associadas ao procedimento manual e às técnicas tradicionais de processamento, os contornos deformáveis têm se popularizado. Ainda que o uso dos contornos deformáveis seja vasto e crescente, aspectos relevantes da teoria ainda têm demandado atenção. Muitas referências têm sido feitas às limitações da técnica impostas sobretudo pelo seu processo evolutivo. A convergência a mínimos locais e o agrupamento indesejado de pontos, por exemplo, limitam o emprego da técnica em cenários ruidosos e complexos como os encontrados em reservatórios de petróleo. Esse trabalho apresenta uma abordagem inédita às limitações dos contornos deformáveis. Pela definição de um segundo problema de minimização são definidas distâncias ótimas dos pontos do contorno deformável segundo critério de optimalidade que contempla as particularidades do contorno buscado. Os resultados demonstram que a técnica proposta é provedora de maior enquadramento entre o contorno buscado e o identificado, define solução definitiva aos problemas do agrupamento e espalhamento indesejados de pontos, aumenta a efetividade dos contornos deformáveis em regiões côncavas e, em acréscimo, define metodologia unicamente capaz de dotar os contornos deformáveis de sensibilidade quanto às particularidades de contorno. / According to the original definition of Terzopoulos, deformable models are curves or surfaces formed by connected points that simulate elastic bodies. By overcoming many limitations associated with the manual procedure and the traditional techniques of processing, deformable contours have become popular. Although the use of deformable contours is vast and growing aspects of the theory still demand attention. Many references have been made to the limitations of the technique imposed by the process evolution process. The convergence to minimum and unwanted bundling points, for example, limit the use of the technic on noisy and complex scenarios as those found in oil reservoirs. This work presents a novel approach to the limitations of deformable contours. By the definition of a second problem of minimization are defined optimal distances of the points of deformable contour according to a optimality criterion that incorporates features of the contour sought. The results show that the proposed technique peovides a larger framework between the contour sought and identified, defines a permanent solution to the problems of grouping and unwanted scattering of points, increases the effectiveness of deformable contours in concave regions and, in addition, defines methodology only able to provide the contours deformable sensitivity about the peculiarities of the contour.