This master thesis is devoted to developing an adaptive control scheme for the well- known Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) technique. The main objective of this adaptive scheme is to asymptotically stabilize a class of Underactuated Mechanical Systems (UMSs) in the presence of uncertainties (not necessarily matched). This class of UMSs is characterized by the solvability of the Partial Differential Equation (PDE) resulting from the IDA-PBC technique. Two propositions are stated in this work to design the adaptive IDA-PBC. One of the main properties of these propositions is that even though the parameter estimation conver- gence is not guaranteed, the adaptive IDA-PBC achieves asymptotic stabilization. To illustrate the effectiveness of these propositions, this work performs simulations of the Inertia Wheel Inverted Pendulum (IWIP) system, considering a time-dependent input disturbance, a type of physical damping, i.e., friction (not considered in the standard IDA-PBC methodology), and parameter uncertainties in the system (e.g., inertia). / Tesis

The aim of this research is to investigate techniques or methodologies that will allow networked applications to adapt to network conditions between end nodes in order to maintain a reasonable Quality of Service and to design, develop and test techniques for achieving such adaptability through the use of a novel content scheduling and delivery scheme. In order to achieve this adaptation, information regarding network conditions, both static and dynamic, has to be first gathered. Since various parties have already conducted substantial research in this area, the task was to review those network measurement techniques and adopt a suitable one for use in the subsequent research. Hence the research is concerned more on how to realize these techniques in practical terms and make those network parameters accessible to applications that are going to adapt based on them. A network measurement service utilizing a standard measurement tool was proposed, developed, tested and subsequently used throughout the project. In this way the research project implementation has help in trying to understand the impact of network measurement on the overall performance of the system and what network metrics are essential in order to help the application make better adaptation decision. The project proceeded further to develop and show case an adaptable network application using a novel scheme in which content was restructured and its delivery rescheduled taking account of the available bandwidth, the content structure, size and order of importance and user specified deadlines, which made use of the network measurement service. In so doing, the project sought to show how and when adaptation can be applied and its potential benefits or otherwise as compared to conventional applications based on best effort systems. The project has proved that by adapting according to the abovementioned scheme in the event of poor network performance, user specified deadlines can be satisfied by reducing the load with contents of high importance being delivered first while contents of less importance being delivered during idle time or user's reading time or ignored if the deadline could not be met. In most cases content of high importance are delivered faster in the adaptable system as compared to the conventional best effort system.

By identifying these sampling of systems, research was undertaken to connect possible systems to create a technology platform. This system being one possibility within ideas already thought out from groups like Archigram and the Metabolism group until today with all the debate from container architecture to prefabricated houses and buildings. This is not an effort to propose new ways of thinking in architecture, but combining ideas and systems out in the open to create a system and a building, being able to fit into context in Africa and also in the systems and context of the bigger world. The Theoretical investigation (pp. 10-16) was not supplied by the student / Dissertation (MArch(Prof))--University of Pretoria, 2008. / Architecture / unrestricted

There has been a long, but disparate discourse among those responsible for our built environment about the inevitability of change on the artifacts we inhabit and those social contracts that influence their making. At a basic level doors and operable windows are an indication of the various flows that move through buildings. Innumerable “passive” and “active” strategies have been devised to allow changes to building floor plans and sections, to control sunlight and wind, to change function, etc. Hundreds, or perhaps thousands, of prototypes have been proposed and developed that change shape or composition in response to various social and environmental pressures. Though not always done with the goals of sustainability in mind, these prototypes often sought to provide increased agency for users, improved energy-efficiency and cost-effectiveness, and other commonly understood goals of sustainability. A number of books, hundreds of articles, and dozens of patents beautifully illustrate many proposed and built examples from which to learn but the descriptive terms employed are greatly varied (i.e., adaptable, animated, collapsible, deployable, enabling, evolutionary, flexible, intelligent, kinetic, manipulable, mutable, open-system, portable, protean, reconfigurable, responsive, revolving, smart, and transformable, etc.) and are therefore difficult to find. By reviewing and synthesizing the existing literature, this study provides a starting point for future research that offers both insight into how these terms have been used over time and a critique of such concerns and the exclusion of the topic within sustainability rating criteria. / text

The goal of my thesis was to produce a building that lives in the spirit of water - a universal substance that senses and responds to the will of the environment around it. Similar to water, the maritime museum adapts its form to external forces while borrowing and redistributing energy throughout an internal cohesive structure. The building serves as an instrument of measurement, etching the pattern of the tides in the night sky and measuring its own shifting form in relation to the moon - its form, constantly reformulates itself, and is analogous to the ebb and flow of progress in history of maritime navigation. Located on North Union Street in Alexandria, Virginia, the building is anchored to the edge of the Potomac, taking full advantage of the endless source of energy that the river provides. The building's form derives itself from the interaction between structure and water. It borrows from the paradoxical behavior of water: the tendency to alternate between platonic spherical forms which occur through internal forces and the unraveling of the sphere in response to gravitational external forces applied to it. The building's circular lighthouse on the northern end serves as a symbolic focal point as well as a central repository for the energy gathered by its two wings. The east wing closest to the water unravels in response to the 4 foot rise and drop of the tides, and borrows that energy to continually recreate an architecture in the image of itself. The west wing of the enclosed portion of the museum serves as a barrier and helps contain the water that is to be released through the lighthouse. The lighthouse also forms a symbolic focal point for the city where light for navigation towards the waterfront, provides a point for people, boats and water to come together. During low tide, a gush of water is released through the lighthouse's inner vortex, as a waterwheel harnesses the lunar energy it is released as a single beam of a light into the sky with surplus energy stored for future use. The interplay between static form and dynamic form creates a building that is both anchored to earth and free to react to the spirit of the movement of the water. / Master of Architecture

The combination of graphical user interface (GUI) and usability evaluation presents an advantage to mastering every piece of software and ensuring perfect quality of work. The increasing demand for online learning is becoming more important, both individually and academically. This thesis introduces and describes an empirical study to investigate and compare how vocabulary can be learned by using different interactive approaches; specifically, a static learning website (with straightforward words and meanings), an adaptable learning website (allowing the user to choose a learning method), an adaptive learning website (a system-chosen way of learning), and a mixed-initiative (mixing approaches and techniques). The purpose of this study is to explore and determine the effects of these approaches in learning vocabu-lary achievement to enhance vocabulary learning for non-English speakers. The par-ticipants were Arabic speakers. The three levels of vocabulary learning activities were categorised as easy, medium, and hard. The independent variables (IVs) were controlled during the experiment to ensure consistency and were as follows: tasks, learning effects, and time. The dependent variables (DVs) were learning vocabulary achievements and scores. Two aims were explored in relation to the effects of these approaches to achievement. The first related to learning vocabularies for non-English speakers tackling the difficulties of the English language and the second related to studying system usability of learning English vocabulary in terms of usability measures (efficiency, frequency of error occurrence, effectiveness, and satisfaction). For this purpose, a vocabulary-learning language website was designed, implement-ed, and tested empirically. To fulfill these requirements, it was first necessary to measure two usability components (efficiency and effectiveness) with a within-subject design of n = 24 subjects recruited and, for users’ satisfaction, a between-subject design of n = 99 subjects recruited, while investigating satisfaction with a system usability scale (SUS) survey. The results and data analysis were described. Overall, the results shown were all satisfactory.

The integration of windcatchers in the urban context of hot-arid context of Tehran needs to address two changes in the current utilization: 1) high density context which makes it harder to access to sufficient airflow in the urban context, and 2) sociocultural shifts towards dependencies on modern mechanical air-conditioning systems. Windcatchers are unique tools existing in the hot-arid regions in the Middle East. Windcatcher uses thermal mass, evaporation techniques, and stack effect to deliver human comfort to the residents of the building. Vernacular windcatchers are useful for moderating the indoor air temperature. Yet, using natural ventilation techniques as passive strategies are outdated in recent decades and there are a couple of reasons for that such as maintenance difficulties, lack of urban air filtration methods, decline of cooling efficiency due to modified airflow patterns, habitable space utilization modifications, and dependencies on mechanical cooling systems. On the other hand, tensile structures have the potential to be considered as a tool to upgrade the windcatchers and use them in the modern urban context which will also help reducing energy and reviving local textile industry. This research tries to propose a method that emphasizes on the adaptability of windcatchers and tensile structures, inhabitant control, airflow control and reuse of heavy thermal mass. Also, the proposed model offers improvements for environmental performance of lightweight textiles, such as particulate matter filtration, kinetic energy transformation, and photoresponse for passive shading or natural daylighting strategies. The main goal of this research is to define the parameters required to enhance inhabitant adaptability with the windcatcher and also natural ventilation cooling system. In this research, important characteristics of Sangelaj neighborhood in Tehran are considered such as existing windcatcher dimensions, micro-climate conditions, and urban morphology. Then, different methods are proposed to develop the heat transfer and airflow analysis of the integration between windcatchers and tensile structures. The research suggests methods for adaptation of windcatchers in existing buildings of Tehran using tensile structures. It also proposes methods for the new buildings in the urban context of Sangelaj neighborhood in Tehran.

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Order in design, whether in music or a building comes from bringing together parts to make a whole. These parts can have an autonomous existence separately and combine to formulate a different event collectively. This thesis is a study of how a building accommodates to the changing needs of a diverse community. It does this by investigating to what end two neighboring apartments, one small and one medium-sized could combine to develop into one large apartment, and revert back again to two apartments when the needs of the inhabitants change. This concept could be paralleled to Jazz, where the musicians find means of altering the sound of the music through improvisation between the notes of the song. The structure of the building like the notes of the melody provides the stationary component and forms the rhythmic beat between the apartments. The pauses or gaps between the structure provide the opportunity for flexibility and improvisation. The melody of the construction comes from the integration of the repetitious permanent structural elements, semipermanent conditions and spontaneously alterable parts. The orchestration of these components allows the building to transform and experience an altering production of its own. / Master of Architecture

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