Master of Arts / Department of Communication Studies / Charles J. G. Griffin / Space commentators and government officials draw on a variety of themes that shape how the public perceives space efforts. By constructing particular visions of outer space and the future of humanity, political leaders have inspired children to become astronauts and consoled the nation after a major tragedy. The future of space exploration and development will likely occur as an extension of existing paradigms that shape the material development of space transportation, space stations, and eventually living in space. Through qualitative interviews, this study illuminates the paradigms of persons working to advance the cause of space exploration and development. In particular, the study analyzes perspectives from individuals in the private sector. It seeks to highlight themes, such as leadership and possible material benefits, so that researchers may begin to construct theories about the specific conditions under which the future of space exploration and development may be shaped or evolve. This enhances our understanding of how themes operate to sustain or alter existing paradigms. In turn, a thematic analysis will generate new understandings of how envisioning seemingly impossible futures and social realities can transform those realities by drawing on conceptions of the past to inform the present and potential futures. To this end, this study employs imagination studies as a theoretical lens to understand how interviewees describe these future social realities. Specifically, the study discusses Engen’s (2002) theory of communicative imagination and seeks to refine it to encompass a process-based approach and flexibility. The presence of communicative imagination is explored in transcripts from qualitative interviews with persons employed in private businesses involved in the research and production of materials and services for space exploration and development. Results from the study reveal five dominant themes: leadership, inspiration and support, core motives, material benefits, and potential futures. Understanding how these themes interact in the process of communicative imagination illuminates the role communication plays in shaping social realities in a variety of circumstances.

The Moon has always been an important milestone in space exploration. After the Apollo landings, it is logical to think that the next step should be a permanent habitation module, which would serve as a testing ground for more ambitious projects to Mars and beyond. For a lunar base to come into realization, it is necessary to assess a number of technological challenges which are due to the harsh conditions that can be found on the Earth's satellite. One of these tasks revolves around energy storage: During the day it is possible to use photovoltaic cells and convert the solar irradiance into electrical energy to power an outpost, however during the lunar night this source is not available. Current investigations establish that the optimal landing site for a permanent mission would be on the rim of the Shackleton crater, near the South Pole. This would reduce the night duration from 14 days to 52 hours of the lunar cycle, which is 29.5 days. While this significantly decreases the exposure to the cold temperatures of the Moon when there is no sunlight, there is still a need for a system to provide energy to the lunar base over this period. Therefore, this study pretends to serve as a possible solution for the aforementioned problem, by developing a system storing energy as thermal energy and then harvesting it as electricity using thermoelectrics. First, a theoretical introduction is presented, where the problem statement is exposed, along with background information regarding the solar illumination and the lunar soil. At the same time, an insight on regolith sintering techniques is given. These techniques are important as a means to providing thermal energy storage during the night cycle. After this, the core of the study is developed: The ideal system for energy storage is broken down into segments, and each of them is explained attending to the possible requirements of a lunar base, while providing supporting simulations when deemed appropriate. These are the solar concentrator, thermal mass, thermoelectric array, cold sink and, if necessary, a pipe network. Following this chapter, a device is proposed. Based on the previously mentioned guidelines, an ideal thermal energy system is simulated and evaluated. Although it is not optimized for efficient energy harvesting, it serves as insight on the design and simulation constraints that appear when one wants to collect electrical energy from thermoelectrics with relatively low efficiency. It was estimated that the prototype would output a mean power of 3.6 Watts over the whole duration of the lunar night. Although in its current state this technology would not present significant benefits over existing energy storage methods such as nickel-hydrogen batteries, this study also proposed several optimization methods which could vastly increase the performance of the device. These include adding more efficient thermoelectric patterns, or modifying the properties of the semiconductors by doping or using nanostructures, and present follow-on opportunities for further research.

When building aircrafts, structural components must be designed for high strength, low cost, and easy assembly.To meet these conditions structural components are often based upon previous designs, even if a new component is developed.Refining previous designs can be a good way of preserving knowledge but can also limit the exploration of new design concepts. Currently the design process for structural aircraft components at SAAB is managed by design engineers. The design engineer is responsible for ensuring the design meets requirements from several different disciplines such as structural analysis, manufacturing, tool design, and assembly.Therefore, the design engineer needs to have good communication with all disciplines and an effective flow of information. The previous design is refined, it is then reviewed and approved by adjacent disciplines.Reviewing designs is an iterative process, and when several disciplines are involved it quickly becomes time consuming.Any time the design is altered it has to be reviewed once more by all disciplines to ensure the change is acceptable.So there is a need for further customizing the design concept to decrease the number of iterations when reviewing. Design Space Exploration DSE is a well known method to explore design alternatives before implementation and is used to find new concepts.This thesis investigates if DSE can be used to facilitate the design process of structural aircraft components and if it can support the flow of information between different disciplines.To find a suitable discipline to connect with design a prestudy is conducted, investigating what information affect structural design and how it is managed.The information flow is concluded in a schematic diagram where structural analysis is chosen as additional discipline. By using topology optimization in a DSE, design and structural analysis are connected.The design space can be explored with regards to structural constraints.The thesis highlights the possibilities of using DSE with topology optimization for developing structural components and proposes a method for including it in the design process.

Hoje em dia, desenvolvedores de sistemas embarcados enfrentam uma crescente complexidade de projeto, tanto nas aplicações quanto nas plataformas usadas para executá-las. O uso de plataformas complexas faz com que os engenheiros precisem fazer escolhas não-triviais, e muitas vezes contra-intuitivas durante a fase de projeto. Para permitir que os projetistas gerenciem esta complexidade, o uso de metodologias baseadas em modelos tem atraído atenção, e dentro deste contexto, a metodologia HIPAO2 está sendo desenvolvida dentro da UFRGS. Dentre os problemas que os engenheiros precisam enfrentar, o mapeamento entre tarefas e processadores em sistemas multiprocessados heterogêneos é um problema NP-completo, onde o espaço de projeto rapidamente se torna grande demais para que seja explorado satisfatoriamente de maneira manual. Este trabalho detalha a extensão das ferramentas que suportam a metodologia HIPAO2, de maneira a incluir facilidades de Exploração de Espaço de Projeto semi-automática para a solução deste problema. A ferramenta proposta faz uso de um algoritmo genético multiobjetivo para evidenciar tradeoffs existentes no projeto, e algoritmos de análise de aplicações modeladas como synchronous dataflow para avaliar possíveis mapeamentos sem um custo computacional proibitivo. / Designers of today’s embedded systems are faced with increasing complexity both in the applications being developed and the platforms they run on. The use of complex platforms means that the engineers need to make non-trivial and many times non-intuitive decisions during the design phase. To help developers work with this complexity, model-driven techniques are gaining attention, and in this context, the HIPAO2 model-driven engineering methodology is being developed at UFRGS. Among the problems that designers must solve, the task-to-processor mapping in heterogeneous multiprocessor systems is an NP-complete problem and the design space will quickly become too large to be explored adequately by humans. This work details the extension of the tools that support HIPAO2 to include semiautomatic Design-Space Exploration capabilities for the mapping problem. The proposed tool includes the use of a multiobjective genetic algorithm to make tradeoffs explicit to the designers; it also uses synchronous dataflow analysis algorithms to evaluate potential alternatives with a reasonable computational cost.

Finite element analysis (FEA) software is used to obtain linear and non-linear solutions to one, two, and three-dimensional (3-D) geometric problems that will see a particular load and constraint case when put into service. Parametric FEA models are commonly used in iterative design processes in order to obtain an optimum model given a set of loads, constraints, objectives, and design parameters to vary. In some instances it is desirable for a designer to obtain some intuition about how changes in design parameters can affect the FEA solution of interest, before simply sending the model through the optimization loop. This could be accomplished by running the FEA on the parametric model for a set of part family members, but this can be very timeconsuming and only gives snapshots of the models real behavior. The purpose of this thesis is to investigate a method of visualizing the FEA solution of the parametric model as design parameters are changed in real-time by approximating the FEA solution using surrogate modeling methods. The tools this research will utilize are parametric FEA modeling, surrogate modeling methods, and visualization methods. A parametric FEA model can be developed that includes mesh morphing algorithms that allow the mesh to change parametrically along with the model geometry. This allows the surrogate models assigned to each individual node to use the nodal solution of multiple finite element analyses as regression points to approximate the FEA solution. The surrogate models can then be mapped to their respective geometric locations in real-time. Solution contours display the results of the FEA calculations and are updated in real-time as the parameters of the design model change.

Space exploration continues to expand humanity’s understanding of the universe. And, while Americans have widely favorable attitudes towards efforts to explore outer space, certain religious beliefs appear to be associated with more negative attitudes towards space exploration and the search for extraterrestrial life. The current study explored the role of religion and creationism on attitudes towards space exploration and the search for extraterrestrial life. Priming techniques were used to test whether increasing the accessibility of religious and creationist concepts led to more negative attitudes towards space exploration and beliefs about extraterrestrial life. Participants (N = 230) encountered an explicit prime of religion, creationism, or a control prior to completing a word fragment task and measures of attitudes towards space exploration and beliefs about extraterrestrial life. The results of Bayesian estimation and hypothesis testing did not support the prediction. However, exploratory analyses indicated very strong evidence of atheists having more positive attitudes towards space exploration and beliefs about extraterrestrial life than theists. These findings suggest that while priming religion and creationism did not appear to influence reported attitudes, attitudes towards space exploration and the search for extraterrestrial life may differ based on belief in god.

Le chiffrement homomorphe est un système de cryptographie permettant la manipulation de données chiffrées. Cette propriété offre à un utilisateur la possibilité de déléguer des traitements sur ses données privées, à un tiers non fiable sur un serveur distant, sans perte de confidentialité.Bien que les recherches sur l'homomorphe soient, à ce jour, encore récentes, de nombreux schémas de chiffrement ont été mis au point. Néanmoins, ces schémas souffrent de quelques inconvénients, notamment, de temps d'exécution particulièrement longs et de coûts mémoire importants. Ces limitations rendent difficile la comparaison des schémas afin de déterminer lequel serait le plus adapté pour une application donnée, c’est-à-dire le moins coûteux en temps et en mémoire.Ce manuscrit présente PAnTHErS, un outil rassemblant plusieurs fonctionnalités permettant de répondre à la problématique citée ci-dessus. Dans l'outil PAnTHErS, les schémas de chiffrement homomorphe sont tout d'abord représentés dans un format commun grâce à une méthode de modélisation. Puis, une analyse théorique estime, dans le pire cas, la complexité algorithmique et le coût mémoire de ces schémas en fonction des paramètres d’entrée fournis. Enfin, une phase de calibration permet la conversion des analyses théoriques en résultats concrets : la complexité algorithmique est convertie en un temps d'exécution estimé en secondes et le coût mémoire en une consommation estimée en mébioctets.Toutes ces fonctionnalités associées ont permis la réalisation d’un module d'exploration qui, à partir d'une application, sélectionne les schémas ainsi que les paramètres d'entrée associés produisant des temps d'exécution et coûts mémoire proches de l'optimal. / Homomorphic encryption (HE) is a cryptographic system allowing to manipulate encrypted data. This property enables a user to delegate treatments on private data to an untrusted third person on a distant server, without loss of confidentiality.Even if current researches in HE domain are still young, numerous HE schemes have been created. Nevertheless, those schemes suffer from some drawbacks, especially, from too long execution times and important memory costs. These restrictions make difficult to compare schemes in order to define which one is the most appropriate for a given application, i. e. the less expensive in terms of time and memory.This thesis presents PAnTHErS, a tool gathering several features to answer to the previous problem. In the tool PAnTHErS, homomorphic encryption schemes are first represented into a common structure thanks to a modeling method. Then, a theoretical analysis evaluates, in the worst case, computational complexity and memory consumption of those schemes according to given input parameters. Finally, a calibration phase enables conversion of theoretical analysis into concrete results: computational complexity is converted into an estimated execution time in seconds and memory cost into an estimated consumption in mebibytes.These gathered features allowed the creation of an exploration method which, from an application, selects best schemes and associated input parameters that implies close to optimal execution times and memory costs.

In a multi-agent system (MAS), the overall performance is greatly influenced by both the design and the control of the agents. The physical design determines the agent capabilities, and the control strategies drive the agents to pursue their objectives using the available capabilities. The objective of this thesis is to incorporate control strategies in the early conceptual design of an MAS. As such, this thesis proposes a methodology that mainly explores the interdependency between the design variables of the agents and the control strategies used by the agents. The output of the proposed methodology, i.e. the interdependency between the design variables and the control strategies, can be utilized in the requirement analysis as well as in the later design stages to optimize the overall system through some higher fidelity analyses. In this thesis, the proposed methodology is applied to a persistent multi-UAV surveillance problem, whose objective is to increase the situational awareness of a base that receives some instantaneous monitoring information from a group of UAVs. Each UAV has a limited energy capacity and a limited communication range. Accordingly, the connectivity of the communication network becomes essential for the information flow from the UAVs to the base. In long-run missions, the UAVs need to return to the base for refueling with certain frequencies depending on their endurance. Whenever a UAV leaves the surveillance area, the remaining UAVs may need relocation to mitigate the impact of its absence. In the control part of this thesis, a set of energy-aware control strategies are developed for efficient multi-UAV surveillance operations. To this end, this thesis first proposes a decentralized strategy to recover the connectivity of the communication network. Second, it presents two return policies for UAVs to achieve energy-aware persistent surveillance. In the design part of this thesis, a design space exploration is performed to investigate the overall performance by varying a set of design variables and the candidate control strategies. Overall, it is shown that a control strategy used by an MAS affects the influence of the design variables on the mission performance. Furthermore, the proposed methodology identifies the preferable pairs of design variables and control strategies through low fidelity analysis in the early design stages.

Thesis (M.M.A.S.)--School of Advanced Airpower Studies, 1995. / Subject: Whether spacepower's limitations are predominantly inherent to the space environment or are self-imposed by the current US approach to space. Cover page date: [1995]. Vita. Includes bibliographical references.

Objetivando implementar um sistema embarcado baseado principalmente em software, duas abordagens ortogonais estão sendo propostas: Desenvolvimento Baseado em Plataformas, que maximiza o reuso; Desenvolvimento Baseado em Modelos, que aumenta o nível de abstração utilizando conceitos de orientação a objetos e UML para modelar uma aplicação. Porém, com o aumento do nível de abstração, engenheiros de software não possuem a idéia exata do impacto de suas decisões de modelagem em questões importantes, como desempenho, e consumo de energia e de memória para uma plataforma embarcada específica. Neste trabalho, propõe-se estimar a memória de dados e de programa, o desempenho e o consumo de energia, diretamente de especificações em UML, como intuito de realizar a exploração do espaço de projeto já nos estágios iniciais do processo de desenvolvimento. Resultados experimentais apresentam erros reduzidos, quando componentes da plataforma são reutilizados e seus custos já são conhecidos para uma plataforma alvo. Aplicações reais foram modeladas de diferentes formas e demonstram a eficiência da abordagem de estimativa para o estagio inicial de exploração do espaço de projeto, permitindo ao desenvolvedor avaliar e comparar diferentes soluções de modelagem. Os valores estimados utilizados na exploração do espaço de projeto podem alcançar taxas de erros inferiores a 5%. / In order to quickly implement an embedded system that is mainly based on software, two orthogonal approaches have been proposed: Platform-based Design, which maximizes the reuse of components; and Model Driven Development, which rises the abstraction level by using object-oriented concepts and UML for modeling an application. However, with this increasing of the abstraction level, software engineers do not have an exact idea of the impact of their modeling decisions on important issues such as performance, energy, and memory footprint for a given embedded platform. This work proposes to estimate data and program memory, performance, and energy directly from UML model specifications to explore the design space in the early steps of development process. Experimental results show a very small estimation error when platform components are reused and their costs on the target platform are already known. Real-life applications are modeled in different ways and demonstrate the effectiveness of the estimates in an early design space exploration, allowing the designer to evaluate and compare different modeling solutions. The estimated values used in the design space exploration can achieve errors as low as 5%.