Accurate, practical, and affordable pose tracking on manually operated C-arm fluoroscopes is a major technical challenge. Conventional tracking methods, such as optical cameras and radiographic fiducials, are hampered by significant shortcomings. Optical cameras are delicate, costly, and have a complex system setup that is easily susceptible to camera obstruction in cluttered operating room. Radiographic fiducials occupy a significant portion of the fluoroscopic imaging space. Using fiducials also requires segmentation that limits clinical use. In this thesis, an alternative form of tracking is proposed to encode the rotational joints of manually operated C-arms using a tilt sensing accelerometer for tracking the C-arm rotational pose. The technique is evaluated by affixing an accelerometer to a full-scale C-arm where a webcam is used as a substitute for X-ray imaging. Ground truth C-arm rotational poses were obtained from the webcam by tracking a checkerboard plate. From these rotational poses, a series of angle and structural correction equations were formulated that can properly relate the accelerometer angle readings to the C-arm rotational pose in real-time and compensate for systematic structural C-arm deformations, such as sagging and bending. Real-time rotational pose tracking of the primary and secondary joint rotations of the C-arm showed an accuracy of 0.5 degrees in the entire range of interest. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2011-01-28 12:07:32.781

Syfte Idag är det få barn som når upp till de fysiska aktivitetsrekommendationerna och detta är det huvudsakliga motivet till att studien genomförs. Syftet med denna studie var att undersöka elevers fysiska aktivitet under raster på skolor med varierande utformning på skolgården. Metod För att besvara syftet valdes en kvantitativ metod med accelerometrar, samt en klassificering av skolgårdar genom observationer. Även enkäter har använts som datainsamlingsmetod. Eleverna bar accelerometrar under en dag och data samlades in under två raster. Skolgårdarna klassificerades utifrån fyra olika komponenter som definierats som stimulerande komponenter i den tidigare forskningen: tillgängligheten av olika faciliteter, lekutrustning/löst material,målade markeringar samt tillgängligheten och antalet utrymmen. Totalt deltog sex skolor i studien, tre skolor klassificerades med en tillräcklig skolgård och tre klassificerades med en otillräcklig skolgård. Det var 114 elever som deltog i studien, varav 63 flickor och 51 pojkar. Resultat Resultatet visade att det fanns signifikanta skillnader mellan de tillräckliga och otillräckliga skolgårdarna. På de tillräckliga skolgårdarna, spenderades 27 % av rastens tid i MVPA (Moderate-to-vigorous intensity physical activity = måttlig till högintensiv fysisk aktivitet),och 28 % i SED (sedentary= stillasittande), medelvärdet på antal steg var 3484 stycken. På de otillräckliga skolgårdarna spenderades 11 % i MVPA och 60 % i SED, medelvärdet på antalsteg var 1554 stycken. Slutsats Resultatet visade på att den fysiska aktiviteten och den stillasittande tiden skiljer sig mellan de två olika klassificeringarna på utformningen av skolgårdarna. Elever på de skolor som klassificerats med tillräckliga skolgårdarna spenderar mer tid av rasten i MVPA och mindre tid i SED, än vad de otillräckliga skolgårdarna gör. Detta kan ge en indikation på att skolgården kan stimulera barn till fysisk aktivitet under rasterna i skolan.

Improving physical activity (PA) participation is a public health priority in developed and developing countries to curb the substantial and growing prevalence of lifestyle-related diseases. Early childhood may be an especially important time to encourage PA; however, there is a paucity of research in this area. The aim of this research was to contribute to the limited body of work in PA in early childhood by investigating PA measurement approaches in young children and applying this knowledge to determine socio-environmental associations of preschool PA. An initial literature review provided the background for the thesis and determined the approaches taken in the ensuing chapters. A second literature review provided a detailed critique of research specific to PA measurement in early childhood to further inform the empirical studies. Information for the empirical chapters was drawn from three research projects: two studies were completed that assessed tools for objectively measuring PA in young children (pedometers and accelerometers), and these studies informed a final project to quantify associates of PA in a sample of preschool-aged children. Novel and important findings from the preliminary studies were that pedometer accuracy for measuring free-living PA and walking in children aged 3-5 years was poor, especially for pedometers worn at the back of the child, or during slow walking. Furthermore, when investigating the utility of accelerometers (more complex and frequently adopted tools) to quantify PA intensity in preschoolers, their application and use of commonly employed thresholds resulted in systematic underestimation of PA intensity and poor agreement (=0.09) when compared with a direct observation criterion measure. Application of existing accelerometer thresholds to classify PA intensity in preschoolers was therefore likely to yield biased estimates. Given the dearth of robust alternatives, a novel approach was developed to calculate individual activity rates from the raw accelerometer data. To account for over-dispersion in accelerometer counts, daily average activity rates per second were derived for each participant using negative binomial generalised estimating equation (GEE) models with a first-order autoregressive (AR1) correlation structure. These rates were assumed to be exchangeable between days and normally distributed. Potential socio-environmental associates of children’s activity rates and body size were thus assessed using normal GEE models with exchangeable correlation structures. Parental PA and child age were independently and significantly associated with child activity rates (P≤0.04). No relationships between child body size and PA or television (TV) exposure were found. Common approaches to PA measurement and data consideration were challenged in this research and novel robust methods devised utilising contemporary statistical methods. Accelerometer data can be successfully reduced to individual activity rates to mitigate current issues related to objective PA quantification with preschoolers. Parental involvement in preschool PA interventions is worthy of further investigation, and younger children may stand to benefit more from increased activity. Further exploration of the complex interactions between PA, exposure to media, and health outcomes in preschool-aged children is warranted.

RAMOS, S. P. Análise da viabilidade técnica dos levantamentos de baixo custo de perfil e irregularidade longitudinal de pavimento com o uso de acelerômetros controlados por arduino auxiliado por bicicleta. 2017. 113 f. Dissertação (Mestrado em Engenharia de Transportes)–Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by Marlene Sousa (mmarlene@ufc.br) on 2017-08-29T16:33:29Z No. of bitstreams: 1 2017_dis_spramos.pdf: 6011113 bytes, checksum: c11cfa0615a6da726476a6166777b7f2 (MD5) / Approved for entry into archive by Marlene Sousa (mmarlene@ufc.br) on 2017-08-29T16:34:48Z (GMT) No. of bitstreams: 1 2017_dis_spramos.pdf: 6011113 bytes, checksum: c11cfa0615a6da726476a6166777b7f2 (MD5) / Made available in DSpace on 2017-08-29T16:34:48Z (GMT). No. of bitstreams: 1 2017_dis_spramos.pdf: 6011113 bytes, checksum: c11cfa0615a6da726476a6166777b7f2 (MD5) Previous issue date: 2017-06-30 / User safety and rolling comfort are functional parameters that can be evaluated, among other criteria, by roughness . Given that there is a strong relation between the profile and the longitudinal irregularities of a pavement, this affinity allows to analyze the evolution of that parameter. In order to carry out the survey of a longitudinal profile of a pavement and the evaluation of roughness , according to the current norms, we can mention, respectively, the level and sighting methods and the laser profilometer. The first one demands a lot of time and physical effort from the operators and the second, a lot of financial resources, since it is a n equipment that costs almost R $ 400,000 ,00 . Thus, it is reasonable to analyze the feasibility of the use of new technologies in order to reconstruct a trajectory related to the longitudinal profile of a pavement and to evaluate an d monitor the evolution of roughness in a practical and economical way. One of the ways to obtain the profile and to evaluate the roughness in this work was the use of inertial sensors, such as an accelerometer. This sensor controlled by an a rduino microco ntroller provides acceleration data, which, after processing the data using the Matlab, Excel, Proval and Minitab software, sought to verify the quality and behavior of the measured signals in order to evaluate the capacity Of the sensor to reconstruct the longitudinal profile and the potential of the equipment to evaluate the longitudinal irregularities of a pavement. In the data collection stage, a Scottish fork and an air rail trolley were used in the laboratory, and a bicycle, with which several passes were made in an experimental section located in the Pici Campus of the Federal University of Ceará. The acceleration data obtained by the accelerometer were processed through digital signal filters and correlated with the International Roughness Index (IRI ) values. By the analysis of the results, it was possible to conclude that the equipment is not efficient to obtain the longitudinal profile of a pavement, due to the low speed of the bicycle. However, the accelerometer controlled by arduino had a high pot ential to evaluate the roughness of a pavement, with 85% of satisfactory results. / A segurança dos usuários e o conforto ao rolamento são parâmetros funcionais que podem ser avaliados, entre outros critérios, pela irregularidade longitudinal. Dado que há uma forte relação entre o perfil e as irregularidades longitudinais de um pavimento, esta afinidade permite analisar a evolução daquele parâmetro. Para se executar o levantamento de perfil longitudinal de um pavimento e a avaliação de irregularidad e longitudinal, de acordo com as normas atuais, pode - se citar, respectivamente, os métodos de nível e mira e do perfilômetro a laser . O primeiro demanda muito tempo e esforço físico dos operadores e o segundo, muitos recursos financeiros, por ser um equipa mento que chega a custar quase R$ 400.000,00 . Dessa forma, torna - se razoável analisar a viabilidade do uso de novas tecnologias com o intuito de se reconstruir uma trajetória referente ao perfil longitudinal de um pavimento e avaliar e monitorar a evolução da irregularidade longitudinal de modo prático e econômico. Uma das maneiras para se obter o perfil e avaliar a irregularidade longitudinal , neste trabalho, foi pelo uso de sensores inerciais, como um acelerômetro. Este sensor controlado por um microcontr olador arduino fornece dados de aceleração, dos quais , após o processamento dos dados pelos softwares Matlab, Excel, Proval e Minitab, procurou - se verificar a qualidade e o comportamento dos sinais medidos com o objetivo de se avaliar a capacidade de o se nsor reconstruir o perfil longitudinal e o potencial do equipamento de avaliar as irregularidades longitudinais de um pavimento. Na etapa de obtenção dos dados, foram utilizados um garfo escocês e um carrinho de trilho de ar , em laboratório, e uma biciclet a, com a qual foram realizadas várias passagens em um trecho experimental localizado no Campus do Pici da Universidade Federal do Ceará. Os dados de aceleração obtidos pelo acelerômetro foram processados através de filtros digitais de sinais e correlaciona dos com os valores do Índice Internacional de Irregularidade ( International Roughness Index – IRI). Pela análise dos resultados , foi possível concluir que o equipamento não é eficiente para a obtenção do perfi l longitudinal de um pavimento , devido à baixa velocidade da bicicleta. No entanto, o acelerômetro controlado por a rduino apresentou elevado potencial para avaliar a irregularidade longitudinal de um pavimento, com 85% de resultados satisfatórios.

abstract: In this thesis, an approach to develop low-frequency accelerometer based on molecular electronic transducers (MET) in an electrochemical cell is presented. Molecular electronic transducers are a class of inertial sensors which are based on an electrochemical mechanism. Motion sensors based on MET technology consist of an electrochemical cell that can be used to detect the movement of liquid electrolyte between electrodes by converting it to an output current. Seismometers based on MET technology are attractive for planetary applications due to their high sensitivity, low noise, small size and independence on the direction of sensitivity axis. In addition, the fact that MET based sensors have a liquid inertial mass with no moving parts makes them rugged and shock tolerant (basic survivability has been demonstrated to >20 kG). A Zn-Cu electrochemical cell (Galvanic cell) was applied in the low-frequency accelerometer. Experimental results show that external vibrations (range from 18 to 70 Hz) were successfully detected by this accelerometer as reactions Zn→〖Zn〗^(2+)+2e^- occurs around the anode and 〖Cu〗^(2+)+2e^-→Cu around the cathode. Accordingly, the sensitivity of this MET device design is to achieve 10.4 V/G at 18 Hz. And the sources of noise have been analyzed. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2015

abstract: The health benefits of physical activity are widely accepted. Emerging research also indicates that sedentary behaviors can carry negative health consequences regardless of physical activity level. This dissertation explored four projects that examined measurement properties of physical activity and sedentary behavior monitors. Project one identified the oxygen costs of four other care activities in seventeen adults. Pushing a wheelchair and pushing a stroller were identified as moderate-intensity activities. Minutes spent engaged in these activities contribute towards meeting the 2008 Physical Activity Guidelines. Project two identified the oxygen costs of common cleaning activities in sixteen adults. Mopping a floor was identified as moderate-intensity physical activity, while cleaning a kitchen and cleaning a bathtub were identified as light-intensity physical activity. Minutes spent engaged in mopping a floor contributes towards meeting the 2008 Physical Activity Guidelines. Project three evaluated the differences in number of minutes spent in activity levels when utilizing different epoch lengths in accelerometry. A shorter epoch length (1-second, 5-seconds) accumulated significantly more minutes of sedentary behaviors than a longer epoch length (60-seconds). The longer epoch length also identified significantly more time engaged in light-intensity activities than the shorter epoch lengths. Future research needs to account for epoch length selection when conducting physical activity and sedentary behavior assessment. Project four investigated the accuracy of four activity monitors in assessing activities that were either sedentary behaviors or light-intensity physical activities. The ActiGraph GT3X+ assessed the activities least accurately, while the SenseWear Armband and ActivPAL assessed activities equally accurately. The monitor used to assess physical activity and sedentary behaviors may influence the accuracy of the measurement of a construct. / Dissertation/Thesis / Ph.D. Kinesiology 2012

Internet of Things, has started to mark its existence from past few years. Right from its inception with a coke machine at Carnegie Mellon University, it has come a long way, connecting billions of devices to internet. This journey is well supported by the advancements in networking, hardware miniaturization and sensing capabilities. Diverse nature of applications of Internet of Things, has cut the communication barriers between the varieties of fields ranging from manufacturing industry to health-care industry. Smart Home is one such application of Internet of Things. Connectivity of home appliances, to achieve automation in living, defines Smart Home. Out of welter of applications that are derived from Internet of Things, this thesis concentrates on Smart Home. Smart Home, in practical is expected to conserve lot of energy, by achieving automation of home appliances, on par with best living experience. Existing technologies such as Z-wave, One-Net, ZigBee, Insteon, had already occupied the Smart Home communication. However, these technologies face the problem of identifying the smart devices uniquely and also exhibit security vulnerabilities. Proposed scheme exploits accelerometer fingerprinting to identify the smart devices uniquely. Security vulnerabilities of existing protocols are addressed by encrypting the data on move with CCM mode of AES encryption.

Please read the abstract in the front pages of the file named 00dissertation / Dissertation (MEng (Mechanical))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / unrestricted

abstract: Micro Electro Mechanical Systems (MEMS) based accelerometers are one of the most commonly used sensors out there. They are used in devices such as, airbags, smartphones, airplanes, and many more. Although they are very accurate, they degrade with time or get offset due to some damage. To fix this, they must be calibrated again using physical calibration technique, which is an expensive process to conduct. However, these sensors can also be calibrated infield by applying an on-chip electrical stimulus to the sensor. Electrical stimulus-based calibration could bring the cost of testing and calibration significantly down as compared to factory testing. In this thesis, simulations are presented to formulate a statistical prediction model based on an electrical stimulus. Results from two different approaches of electrical calibration have been discussed. A prediction model with a root mean square error of 1% has been presented in this work. Experiments were conducted on commercially available accelerometers to test the techniques used for simulations. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2020

The goal of this paper is to suggest suitable method for angle measuring of mobile robot. There are being analyzed 3 different sensors – gyroscope, accelerometer and electronic compass in the prologue. Their advantages and disadvantages in the theoretical way are being explained in this part and also their opportunities of use in the practical way. In the following parts the work is focused on MEMS gyroscopes and their opportunities of use in the practical way with regard to achievable exactness and to the application for development of its exactness. The application of device together with main SW for microcontroller and the valuation of achievable exactness and determined facts are being described in the conclusion part.