Thesis (Ph. D.)--Florida State University, 2006. / Advisor: Emmanuel G. Collins, Jr., Florida State University, College of Engineering, Dept. of Mechanical Engineering. Title and description from dissertation home page (viewed Sept. 21, 2006). Document formatted into pages; contains xiii, 87 pages. Includes bibliographical references.

Thesis (Ph. D.)--Drexel University, 2007. / Includes abstract and vita. Includes bibliographical references (leaves 100-104).

Thesis (Ph. D.)--Computing, Georgia Institute of Technology, 2008. / Isbell, Charles, Committee Member ; Lipkin, Harvey, Committee Member ; Balch, Tucker, Committee Member ; Bobick, Aaron, Committee Member ; Arkin, Ronald, Committee Chair.

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Fujimoto, Richard, Committee Member ; Ma, Xiaoli, Committee Member ; Fekri, Faramarz, Committee Member ; Copeland, John, Committee Member ; Akyildiz, Ian, Committee Chair.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

A method of estimating the relative position and orientation of a known target satellite is presented, using only passive imagery. Such a method is intended as a prelude to a system required in future autonomous satellite docking missions. Using a single monocular image, and utilising knowledge of the target spacecraft, estimation of the target's six relative rotation and translation parameters with respect to the camera are found. Pose estimation is divided into modular sections. Each frame is processed to detect the major lines in the image, and correspondence information between detected lines and a-priori target information is estimated, resulting in a list of line-to-model correspondences. This correspondence information is used to estimate the pose of the target required to produce such a correspondence list. Multiple possible pose estimates are generated and tested, where each estimate contains the three rotation and translation parameters. The best estimates go through to the least-squares minimisation phase, which reduces estimation error and provides statistical information for multi-frame filtering. The final estimate vector and covariance matrix is the end result for each frame. Estimates of the target location over time allow the relative orbit parameters of the target to be estimated. Location estimates are filtered to fit an orbit model based on Hill's Equations, and statistical information gathered with each estimate is including in the filter process when estimating the orbit parameters. These orbit parameters allow prediction of the target location with time, which will enable mission planning and safety analysis of potential orbit manoeuvres in close proximity to the target. Testing is carried out by a detailed simulation system, which renders accurate images of the target satellite given the true pose of the target with respect to the inertial reference frame. The rendering software used takes into account lighting conditions, reflections, shadowing, specularity, and other considerations, and further post-processing is involved to produce a realistic image. Target position over time is modelled on orbit dynamics with respect to a defined inertial frame. Transformation between inertial, target, and camera frames of reference are dealt with, to transform a rotating target in the inertial frame to the apparent rotation in the camera frame.

Made available in DSpace on 2014-06-12T15:52:31Z (GMT). No. of bitstreams: 1 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / Atores Sintéticos são agentes inteligentes que possuem personalidade, atuam em ambientes multimídias ou virtuais e são representados graficamente por avatares. Estas entidades são utilizadas em sistemas de simuladores como forma de enriquecer a interação entre a aplicação e seus usuários, proporcionando assim aumento da credibilidade do projeto. Com a sua popularização sugiram vários projetos que os utilizam. Estes projetos têm diversos aspectos em comum. Por exemplo, neles seus atores se comunicam e possuem modelos de personalidade. Contudo, apesar das similaridades os projetos encontrados na literatura foram implementados de forma independente. Ou seja, tiveram seu código fonte desenvolvido do zero. Porém, no âmbito dos sistemas multiagentes tal problema não ocorre devido à existência de diversos frameworks multiagentes que agrupam as funcionalidades comuns a tais sistemas, fazendo com que o desenvolvedor implemente apenas o que é relativo ao seu contexto de simulação. Porém, estes frameworks não são utilizados em sistemas multiarores, pois não suportam as peculiaridades dos sistemas multiatores. Buscando solucionar esse problema, este trabalho apresenta o FAct (Framework for Actors), um projeto criado especificamente para auxiliar na construção sistemas multiatores. Ele focado nas características peculiares destes sistemas e tem como principal objetivo reduzir o custo e tempo de desenvolvimento para os projetos baseados nesta tecnologia. Como forma de exemplificar o uso do FAct e avaliar o seu impacto no desenvolvimento de simuladores multiatores, serão apresentados dois simuladores implementados com base no framework

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Climate change affects water resources suitable for human consumption, transforming water quality and quantity. These changes exacerbate vulnerabilities of human society, increasing the importance of adequately protecting and managing water resources and supplies. Growing urban populations provide an additional stress on existing water resources, particularly increasing the vulnerability of people living in poor neighbourhoods. In urban areas, official responses to climate change are currently dominated by Disaster Risk Management (DRM); however, more recently Integrated Water Resources Management (IWRM) has emerged to support the integration of climate change adaptation in water resource planning. Based on a case study of the city of Douala, Cameroon, the thesis examines the operational implementation of both frameworks, combining observations, semi-structured interviews with different stakeholders and a survey carried out in three poor communities. The research highlights the challenges of improving the joining of both frameworks to adequately reach the urban poor, whilst being alert to, and responsive to, the autonomous adaptation strategies the poor autonomously implement and develop. At present, the IWRM and DRM frameworks are implemented separately and do not clearly reach the urban poor who face three major water-related issues (flooding, water-related diseases and water access). Other institutional water-related measures and projects are carried out by authorities in the low-income communities, but the institutions still struggle to manage the delivery of basic services and protect these communities against hazards. The lack of effective outcomes of the institutional water-related measures and projects has led to a strong process of autonomous adaptation by inhabitants of poor communities. Driven by their adaptive capacity supported by the abundance in groundwater resources, they use coping and adaptive strategies to reduce their vulnerability to water-related issues, such as alternative water suppliers. Similarly, the frequency of the flooding hazard has led the urban poor to develop practices to minimise disaster impacts. However, the autonomous strategies developed face limitations caused by the natural and build environment. In this context, the autonomous strategies of the urban poor and the strategies appear to have a strong influence on each other. While institutional projects have initiated spontaneous strategies, other strategies reduce the willingness of the low-income neighbourhoods to participate in the implementation of official, externally derived development projects.

The use of potential field based navigation schemes in robotics has been limited by inherent local minima issues. Local minima traps, small passages, unstable motion, and targets positioned near objects all pose major concerns when using potential fields for local vehicle control. This work proposes a new algorithm, "Re-Active Vector Equilibrium" (RAVE) that mitigates many of these issues. The vehicle representation model is expanded to use multiple points subject to potential calculation and the addition of two forces, a velocity dependent "risk force" (F_rsk) and a velocity and direction dependent "tangential force" (F_tan). The vehicle representation model is also expanded from a single reactive point to a series of points that define the vehicle body, providing better and simpler vehicle control. This has the effect of simplifying the required calculations at the cost of increasing the calculation count. The risk force, F_rsk, allows for dynamic adaptation to the immediate environment by acting in opposition to the net obstacle force, and is inversely proportional to the vehicle speed. The tangential force, F_tan, encourages better wall-following behaviour and provides a biasing mechanism to resolve obstacle aligned with target local minima issues.