Thesis (Ed.M)--Boston University

The proliferation of mobile computing devices with powerful sensing and communication capabilities has created an immense social landscape of awareness and connectedness. Social media applications have been largely designed for asynchronous expression and collaboration among individuals. Though these models have served as suitable surrogates for social interaction in a rapidly evolving digital age, they have been insufficient at connecting people spatially and temporally. This report describes Revolver: an appli- cation utilizing the state-of-the-art in mobile and distributed computing to provide users with a shared sense of time and space. Revolver allows users to synchronously capture image data of their surroundings with the ability to virtually reconstruct an event from the separate sources. We present the ratio- nale for the project, design considerations, implementation details, results of the prototyping effort, and conclusions to carry this project to future phases of development for viable deployment. / text

V ANGLICKÉM JAZYCE Title: Choreography short program of synchronized skating Name: Bc.Hana Křivová Goals of the thesis: This diploma thesis deals with composition of a short program of synchronized skating group Daisies. It focuses on particular formations and step sequences in accordance with the Synchronized skating rules. Method: The thesis is of a descriptive character. The methods used in the thesis are controlled observation and interview. Literature, experience and information gained in international meetings and competitions, further consultations with international coaches and technical specialists are commonly used in the thesis. Results: The thesis gives clear description of the Synchronized skating rules for Senior category. It shows the choreography of the short program of senior team Daisies. It uses pictures and description of particular formations, with arrangement on the ice. Key words: synchronized skating, synchronized skating history, short program, choreography

Titel: Choreography short program of synchronized skating Name: Bc.Hana Křivová Goals of the thesis: This diploma thesis drala with composition of a short program of synchronized skating group Daisies. It focuses on particular formations and step sequences in accordance with the Synchronized skating rules. Metod: The thesis is sof a descriptive character. The methods used in the thesis are controlled observation and interview. Literature, experience and information gained in international meetings and competitions, further consultations with international coaches and technical specialists are commonly used in the thesis. Results: The thesis gives Clar description of the Synchronized skating rules for Senior category. It show the choreography of the short program of senior team Daisies. It uses Picture and description of particular formations, with arrangement on the ice. Key words: synchronized skating, synchronized skating history, short program, choreography

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Wind power generation influences on the quality of the power grid. Because wind velocity is consistently changing this change causes unstable wind power generation. Since more wind power is expected to be used in the future, it is crucial to study the influence of the wind penetration level on normalized-damping ratio and damped-resonant frequency. In this thesis three types of calculated data were used to analyze the effect of wind penetration level on the Texas power grid: the percentage of wind power generation in Texas, generator-unit trip damping coefficient, and damped-resonant frequency. The percentage of wind energy was calculated from wind data provided by the Electric Reliability Council of Texas. The damping coefficient and damped-resonant frequency values are the indicators of power system stability and were calculated from synchronized phase data from the Texas power grid. The synchronized phase measurements were collected from the University of Texas at Austin and the wind farm near the Mc-Donald observatory. The data analyzed in this paper were from September 2009 to February 2010. The wind data were correlated to the grid-stability indicators which allowed us to interpret the status of the power grid according to the wind penetration level. When the wind penetration level increased over 11 %, five generator trip events occurred with damping coefficient values ten times higher than those of the regular unit trips. Moreover, during those events, damped-resonant frequency values rose nearly four times higher than the frequency values of other events. The results of this study may lead us to the conclusion that simply increasing the capacity of wind power generation will cause the power system to become unstable, and this will result in low quality of electricity. Therefore, further study is needed to determine the optimum amount of wind power generation without causing instability in the power grid. / text

O objetivo do presente estudo foi investigar os efeitos do tipo de modelo, boneca e humano, na aprendizagem das habilidades motoras do nado sincronizado, mais especificamente na figura tina (Experimento 1), bem como os efeitos da ordem da apresentação do modelo, boneca-humano ou humano-boneca na aprendizagem da mesma figura (Experimento 2). Participaram do Experimento 1, 20 sujeitos, partindo dos seguintes critérios de inclusão: voluntários do sexo feminino, com idade média de 23,1 anos (DP= 4,1), adaptados ao meio aquático, capazes de deslocar-se na parte rasa da piscina, de flutuar com auxílio das mãos, sem experiência anterior com qualquer das habilidades do nado sincronizado. A tarefa consistiu na execução da tina, que compreende a execução de uma sequência composta por 3 posições e 2 movimentos de transição: (1) Posição Inicial; (2) Transição para a tina; (3) Posição de Tina; (4) Transição para a posição final; e, (5) Posição Final. Os sujeitos foram distribuídos em dois grupos de 10 participantes cada, o grupo modelo boneca (GB) e o grupo modelo humano (GH). Após um pré-teste composto de seis tentativas consecutivas de execução da tina a partir de instrução verbal, todos executaram 60 tentativas a partir de demonstração e instrução verbal. As demonstrações tanto do modelo boneca como do modelo humano foram fornecidas a cada tentativa, por vídeo. Após intervalo de 10 minutos, todos foram submetidos a um pós-teste, também composto de seis tentativas consecutivas de execução da tina a partir de instrução verbal. No dia seguinte, todos os sujeitos, independente do grupo foram submetidos ao teste de retenção, composto de dois blocos de 6 tentativas, sem qualquer tipo de instrução. A amostra do Experimento 2 foi constituída por 20 sujeitos, voluntários do sexo feminino, com idade média de 21,6 anos (DP= 2,8), adaptados ao meio aquático, capazes de deslocar-se na parte rasa da piscina, de flutuar com auxílio das mãos, sem experiência anterior com qualquer das habilidades do nado sincronizado, cuja tarefa era a mesma do Experimento 1, a execução da tina. Foram formados dois grupos de 10 participantes, sendo um deles com modelo boneca seguido de modelo humano e outro com modelo humano seguido de boneca. Após a aplicação de pré-teste, somente com instrução verbal, cada grupo executou 10 blocos de aquisição. Dez minutos após a fase de aquisição, os sujeitos executaram um bloco pós-teste, em que só foi fornecida instrução verbal, seguido, no dia seguinte, de dois blocos de teste de retenção, cada um constituído de seis tentativas. Entre os blocos 1 e 5 da fase de aquisição, as participantes receberam uma demonstração a cada tentativa de seu primeiro modelo, boneca ou humano, de acordo com seu grupo. Do bloco 6 ao 10 da fase de aquisição, as participantes receberam uma demonstração a cada tentativa do segundo modelo, humano ou boneca. Os resultados mostraram que nas medidas de desempenho global e de desempenho por componente não houve efeito do tipo de modelo, boneca ou humano (Experimento 1) e da ordem de apresentação do modelo na aprendizagem da tina do nado sincronizado. Nesse sentido concluiu-se que o modelo apresentado na demonstração associado à instrução verbal, não afeta a aprendizagem da tina, podendo ser utilizada a boneca e ou o modelo humano / The objective of the present study was to investigate the effects of the type of model, synchro doll and human, in the motor learning process of Synchronized Swimming skills, particularly the tub figure (Experiment 1), as well as the effects of the sequence of models presentation in the learning process of the tub, synchro doll followed by the human model, or the human model prior to the synchro doll (Experiment 2). Experiment I was based on the performance of 20 female volunteer subjects, average age 23,1 years old (SD =4,1), adapted to aquatic environment, able to move on the shallow part of the pool and to fluctuate without using their hands. The task consisted of tub figure of the Synchronized Swimming consisting of 5 positions and 2 transition movements: starting position, tub transition, tub position, final transition and final position. After a pre-test in which all made 6 consecutive trials with verbal task description, the subjects were distributed in two groups consisting of 10 participants which, and made 60 trials with verbal task description and one demonstration per trial, the latter consisting of video instruction showing either a synchro doll model, or a human model. After 10 minutes all were submitted to a post-test, which consisted of 6 consecutive trials with verbal instructions only. On the following day, the subjects of both groups were submitted to a retention test, composed of two sessions of 6 consecutive trials with no instructions at all. In Experiment 2, 20 novice female subjects, average age 21,6 years old (SD = 2,8), adapted to aquatic environment, able to move on the shallow part of the pool and to fluctuate without using their hands had the same task as in Experiment 1, the performance of the five task components of the tub: starting position, tub transition, tub position, final transition and final position. Two groups of 10 participants were formed, one of them having the synchro doll model prior to the human model, and the other with the human model followed by the synchro doll model. After the pre-test in which all made 6 consecutive trials with verbal task description, each subject was submitted to 10 acquisition sessions. Ten minutes after those, the subjects were submitted to a post-test with verbal instructions only and, on the following day, 2 sessions of retention tests, consisting of 6 trials which, with no instructions at all. During the acquisition sessions 1 to 5 the subjects received one demonstration per trial of the first model, either synchro doll or human, according to their group, During the acquisition sessions 6 to 10 the participants received one demonstration per trial of the other model, either human or synchro doll. The results show that the type of model and the presentation sequence did not affect the global performance nor the performance of the components. So it was concluded that the model presented in demonstration associated to the verbal instructions does not affect tub learning, making it possible to use either the doll or the human model in any sequence

The demand of modern technology is highly required by humans. The Linear motor, one of the most significant inventions, has been playing a vital role in driving component. The Structure of the gantry is the main design and the requirement of high bandwidth and rigidity. Twin-linear motors coupled and paralleled with machining beam are to realize one degree-movement. To prevent the marching beam from deformation, the synchronized motion control becomes an important technology for this machine. This thesis solves the problem of the mechanism coupling by using of the synchronized master command approach which integrates the decouple control and internal model control and taking the mechanism beam as an uncertainty. Both system uncertainties and unknown disturbances occurring in actual implementation need to be carefully considered. And the synchronized motion control of the two linear servo systems with mechanism will be investigated. Better synchronization performance for two motors can therefore be anticipated.

Coordinated or synchronized tasks can always be found in various manufacturing processes, e.g., machining along spatial trajectories, coordinated operations of multi-manipulators, and vacuum pumps, etc. The vacuum pump is a typical device with synchronized motion among those examples. The vacuum pump has played an important role in current semiconductor manufacturing processes. Its pumping feature is achieved by synchronized motion of two mating pump rotors. A common approach to accomplish the synchronized motion is by idle gears. Nevertheless, this design cannot meet serious requirements of vacuum systems demanded by growing manufacturing techniques. In order to provide a complete and proper control strategy for synchronized motion, and to overthrow traditional architecture of vacuum pumps by raising a better control scheme for new generation oil-less products, the paper focuses on synchronized motion control for dual motors. The first objective of here is to develop a control method for synchronized motion of two separated motors. Both system uncertainties and unknown disturbances occurring in actual implementation need to be carefully considered. An experimental setup will also be established for examinations and verifications. And then synchronized motion control of dual motors including two mating screw rotors then will be investigated. During this period, the emphasis will be on solution finding for unexpected contact collision between two rotors. An effective and efficient control strategy will be developed for synchronized motion control of dual motors. Longer operation time and better synchronization performance for two motors can therefore be anticipated.

Abstract Coordinated or synchronized tasks can always be found in various manufacturing processes, e.g., machining along spatial trajectories, coordinated operations of multi-manipulators, and vacuum pumps, etc. The vacuum pump is a typical device with synchronized motion among those examples. The vacuum pump has played an important role in current semiconductor manufacturing processes. Its pumping feature is achieved by synchronized motion of two mating pump rotors. A common approach to accomplish the synchronized motion is by idle gears. Nevertheless, this design cannot meet serious requirements of vacuum systems demanded by growing manufacturing techniques. In order to provide a complete and proper control strategy for synchronized motion, and to overthrow traditional architecture of vacuum pumps by raising a better control scheme for new generation oil-less products, the paper focuses on synchronized motion control for dual motors. The first objective of here is to develop a control method for synchronized motion of two separated motors. Both system uncertainties and unknown disturbances occurring in actual implementation need to be carefully considered. An experimental setup will also be established for examinations and verifications. And then synchronized motion control of dual motors including two mating screw rotors then will be investigated. During this period, the emphasis will be on solution finding for unexpected contact collision between two rotors. An effective and efficient control strategy will be developed for synchronized motion control of dual motors. Longer operation time and better synchronization performance for two motors can therefore be anticipated.