Zugl.: Berlin, Humboldt-University, Diss., 2009.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 100 p. : ill. (some col.), maps (some col.). Vita. Includes abstract. Includes bibliographical references (p. 85-91).

This dissertation systematically explores multiple-input converters (MICs) configuration and topologies, and then proposes improvements on certain beneficial MICs—time-sharing MICs and soft-switching MICs for distributed generation (DG) applications with high voltage transfer ratio. Compared with other MIC families which are derived from same input and output cells, time-sharing MICs have the fewest circuit components. However, time-sharing MICs lack for bi-directional power flow capability due to their special input switches requirement. In addition, their hard-switching characteristic leads to a low efficiency problem when isolation is necessary. The dissertation investigates into time-sharing MIC input switch selection, which leads to a new driving strategy and new input switch combinations. With the new input switch combinations, bi-directional and high efficiency time-sharing MICs are made possible. Besides isolated time-sharing MIC, Soft-switching MICs might also be a common choice for high voltage transfer ratio DG applications. However, the enormous amount of circuit components makes the soft-switching MICs become less attractive. An input cell reduction method is introduced in this dissertation to greatly reduce the component count of isolated MICs, including soft-switching MICs. In addition to the improvement on existing MIC families, a new push-pull connected MIC family is proposed in this dissertation as another choice of high voltage transfer ratio DG applications. Moreover, a comparison among MIC families is made to provide a sense of topologies selection in certain applications. Prototypes of time-sharing dual-input (DI) SEPICs, a push-pull connected DI-Boost converter, and a DI full-bridge (FB) converter are built to verify aspects discussed in this dissertation. Bi-directional power flow capability of time-sharing MIC is confirmed with a time-sharing DI-SEPIC and a soft-switching time-sharing MIC is realized by an isolated time-sharing DI-SEPIC with an active clamping leg. Maximum power point tracking control feasibility in these converters is evaluated with real photovoltaic modules that are connected to the push-pull connected DI-Boost converter that uses a perturb-and-observe method. Finally, an efficiency comparison is made between time-sharing MIC and push-pull connected MIC. / text

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Multitouch technology allows the users to use both their hands and multiple fingers to manipulate digital content directly on the screen. This paper attempts to analyze the actual convenience of bimanual and multifinger manipulation on a multitouch display by conducting three observational experiments and studying how a group of volunteers use their hands and fingers when interacting with digital content on a touchscreen surface. In addition, the participants had to fill in a questionnaire where they give some additional insights on how they experienced the use of multitouch-based interface during the experiments. The results suggest that when participants were performing tasks in which they were instructed to manipulate the digital content as fast as they could, a high percentage of them resorted to the use of at least some level of bimanual manipulation of the digital content. However, when participants were told to perform the tasks calmly the big majority of participants decided to move the objects by using only one hand (unimanual). Same-hand multifinger manipulation was also used by a high percentage of participants when moving several objects simultaneously. Nevertheless, in all three experiments the most common way of moving objects across the screen was by dragging them one at a time (sequential move). Finally, in relation to the personal assessment made by the participants, a total of 70% feel that the possibility for engaging in bimanual interaction, that multitouch interface offers, is a clear benefit and advantage over traditional keyboard and mouse. However, 40% of the respondents feel that the use of mouse still is a more effective and natural form of interaction than multitouch technology.

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This thesis project consists of developing a hand-held, one-thumb input device small enough to be placed on gestural controllers and providing performers with a simple way to select between multiple options with few movements of a thumb. / Most commercial input devices for the thumb make the assumption that buttons are the de facto standard. However, buttons are not always the best solution especially where space is very limited. This project explores a new approach to input design by analyzing the thumb's movements and designing a suitable input device that can track them. The design progression from the first to the last prototype is presented in great detail. / The final prototype is compared to other existing one-thumb input devices used in gestural controllers and mobile computing. The shortcomings of each one-thumb input method is described with the final prototype presented as a possible solution in each case.