Newly released Imaging Ultraviolet Spectrograph/Mars Atmosphere and Volatile EvolutioN (IUVS/MAVEN) measurements of CO2 density in the Martian thermosphere have been used for comparison with the predictions of the Max Planck Institute Martian General Circulation Model (MPI-MGCM). The simulations reproduced (within one standard deviation) the available zonal mean density and derived temperature above 130 km. The MGCM replicated the observed dominant zonal wave number 3 nonmigrating tide and demonstrated that it represents a nonmoving imprint of the topography in the thermosphere. The comparison shows a great dependence of the simulated density and temperature to the prescribed solar flux, atomic oxygen abundances and gravity wave effects, with the former two being especially important in the thermosphere above 130 km and the latter playing a significant role both in the mesosphere and thermosphere.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The accurate measurement of shock and vibration data via flight telemetry is necessary to validate structural models, indicate off-nominal system performance, and/or generate environmental qualification criteria for airborne systems. Digital telemetry systems require anti-aliasing filters designed into them. If not properly selected and located, these filters can distort recorded time histories and modify their spectral content. This paper provides filter design guidance to optimize the quality of recorded flight structural dynamics data. It is based on the anticipated end use of the data. Examples of filtered shock data are included.

ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / Falls prevention efforts for older adults have become increasingly important and are now a significant research effort. As part of the prevention effort, analysis of gait has become increasingly important. Data is typically collected in a laboratory setting using 3-D motion capture, which can be time consuming, invasive and requires expensive and specialized equipment as well as trained operators. Inertial sensors, which are smaller and more cost effective, have been shown to be useful in falls research. Smartphones now contain Micro Electro-Mechanical (MEM) Inertial Measurement Units (IMUs), which make them a compelling platform for gait data acquisition. This paper reports the development of an iOS app for collecting accelerometer data and an offline machine learning system to classify a subject, based on this data, as faller or non-faller based on their history of falls. The system uses the accelerometer data captured on the smartphone, extracts discriminating features, and then classifies the subject based on the feature vector. Through simulation, our preliminary and limited study suggests this system has an accuracy as high as 85%. Such a system could be used to monitor an at-risk person's gait in order to predict an increased risk of falling.

This thesis investigates the problem of sensors used with mobile robots. Firstly, a colour sensor is considered, for its ability to detect objects having the three primary colours Red, Green and Blue (RGB). Secondly, an accelerometer was investigated, from which velocity was derived from the raw data using numerical integration. The purpose of the design and development of the sensors was to use them for robotic navigation and collision avoidance. This report presents the results of experiments carried out on the colour sensor and the accelerometer. A discussion of the results and some conclusions are also presented. It proved feasible to achieve the goal of detecting colours successfully but only for a limited distance. The accelerometer proved reliable but is not yet being applied in real time. Both the colour sensor and the accelerometer proved to be inexpensive. Some recommendations are made to improve both the colour sensor and the accelerometer sensors.

Introduction With an increasing knowledge of the health benefits from physical activity (PA) the interest in objectively measuring PA in free living environment has increased. ActiGraph is the most commonly used accelerometer to objectively measure PA, while ActivPAL is considered gold standard when it comes to measuring sedentary behavior. Aims The aim of this study was to investigate if ActivPAL could be used to measure Moderate to Vigorous Physical Activity (MVPA) instead of ActiGraph. Methods Data from 79 overweight office workers carrying the ActivPAL and ActiGraph device simultaneously were analyzed. All activities with a cadence of 90 steps per minute (spm) or more lasting for at least 30 seconds from one day from ActivPAL data was extracted and compared to the corresponding activity from ActiGraph. An activity was classified as MVPA by using the cut points of 100 spm for ActivPAL and 3208 activity-counts per minute (cpm) for ActiGraph using vector magnitude (VM). Results A correlation of r=0.326 (p<0.001) was seen between ActiGraph and ActivPAL with a Cohen’s kappa of K=0.14, a percentage agreement of 60.7%, a sensitivity of 61.5% with ActiGraph as denominator and a positive predictive value (PPV) of 84.3% for ActivPAL. Neither age nor BMI affected the association between the estimates by these devices. There was no correlation for time spent in MVPA between devices. Conclusion Cadence from ActivPAL cannot replace ActiGraph to measure MVPA in a free living environment in overweight adults.

This thesis aims at developing a prototype for a fall detection bracelet that can connect to the cellular network. The bracelet consists of a processing unit, three sensors, a LTE USB modem and a powerbank. The prototype is aimed at elderly people since up to one out of three over the age of 65-years-old fall each year. Besides elderly people this system can be used in activities which involves substantial height, e.g. climbing and roofing. Statistics has shown that most serious consequences are not a direct result of falling, but from the lack of fast assistance and treatment. If a fall is detected a distress signal, in the form of an SMS message, is sent to a predefined emergency contact. The contents of the SMS messages includes time and date of fall, ambient temperature, fall location coordinates as well as an URL that redirects to the location as seen in Google Maps. The fall detection algorithm is threshold based and was created by first analyzing falls in different direction. It can successfully identify 74,4% of all falls, but as good as up to 91% of falls that are either backwards, forwards or to the left given that the bracelet is attached to the left wrist. The algorithm can further filter out 100% of studied activities that are not falls. Such activities include walking, running and sitting down. This gives an overall Accuracy of 93% for the system. The Accuracy takes into account how well a fall is detected and how well other activities are filtered out. Furthermore, the bracelet was worn for 40 hours, spread out over 11 days, in order to capture data during this persons every day life. During this time no false distress signal was sent to the emergency contact. Limitations of the system has been found to be the GPS module and the fact that the algorithm is threshold based. The location tracking can be improved by utilizing AGPS, which is the same technique that cellphones use. The threshold based system can't be circumvent in a wearable device solution. From this thesis it is indicated that a wearable bracelet can be a reliable fall detection unit. With more extensive falls and field testing even better results can be achieved and it can eventually be pushed as a real product.

La navigation par système inertiel strapdown est aujourd’hui la plus répandue. L’architecture est bien connue et a été très largement améliorée au cours des dernières décennies. Néanmoins, le principe fondamental n’a subi de bouleversement et reste constitué d’une triplette d’accéléromètres et de gyromètres permettant de revenir aux informations d’attitude et de cap.La précision de l’estimation de position repose principalement sur la gamme de performance des capteurs utilisés. En particulier, des applications telles que des lanceurs spatiaux requièrent une très haute précision et des capteurs d’une technologie éprouvée sont utilisés. L’arrivée sur le marché de capteurs inertiels MEMS de haute précision ouvre une alternative à coût réduits couplée à une réduction de masse, volume et de consommation. Les moyens de production des MEMS ainsi qu’une meilleure connaissance des propriétés des matériaux ont permis l’arrivée d’accéléromètres MEMS pouvant rivaliser avec les technologies éprouvées de gamme tactique. Toutefois, les gyromètres de technologie MEMS existantes restent dans une gamme de performance de type industrielle.La présente étude vise à analyser la possibilité d’utiliser des accéléromètres de haute précision pour améliorer les performances gyrométriques, dans l’objectif de réaliser une solution tout MEMS d’unité de mesure inertielle. Une brève introduction sur les techniques de filtrage de Kalman pour la fusion de données est présentée, ainsi que son implémentation pour notre étude. L’analyse théorique se poursuit avec une présentation des résultats expérimentaux.L’étude conclut que l’utilisation d’une paire d’accéléromètres de haute performance et d’un gyroscope de type consommateur permet d’atteindre les performances d’un gyromètre tactique. Les contraintes de définition et de mesure pour l’implémentation du système sont présentées en détail.Cette étude est menée pour la mesure angulaire autour d’un axe unique de rotation, un complément d’étude est nécessaire à l’extrapolation de cette approche pour une mesure générique en 3D. / Strapdown inertial navigation units are the most popular systems used for navigation. The system architecture is well established and has been extensively improved over the past decades. However, the core idea remains same where a triad of accelerometers and gyroscopes provide the attitude and heading information.The accuracy of the position estimate depends on the performance grade of the sensors employed. For applications like space launchers requiring very high accuracy, high-grade devices using traditional technologies are used. The advent of accurate MEMS based sensors offer an exciting low-cost alternative with expected reduction in size and power consumption. MEMS fabrication technology, assisted by improved understanding of material properties have led to accelerometers that can compete with traditional devices for tactical applications. However, the MEMS based solutions currently available for gyroscopes can replace only industrial grade applications.This study attempts to investigate if the currently available high-grade accelerometers can be used to improve the gyroscope performance, towards the final goal of a complete MEMS based solution for inertial navigation units. The study begins with a literature review of current status of technology. A brief explanation of linear Kalman filtering technique for data fusion is presented, along with its implementation concerning this work. The theoretical discussion is then followed by presentation of experimental results.The study found that using a pair of high-grade accelerometers, a consumer grade gyroscope can have its performance upgraded for tactical applications. The design and sensing constraints for realizing this system are discussed in detail.Since this research work primarily concerns with angular rate estimation around a single axis of rotation, further research is recommended for extrapolating this approach for a more general 3-D sensing case.

La localisation précise d’un train sur la voie ferrée est une information vitale pour la gestion du trafic et la sécurité des passagers. Le système européen de contrôle des trains (ETCS) embarque ainsi un accéléromètre mono axe mesurant l’accélération longitudinale du train. Ce capteur est l’un des nombreux capteurs présents à bord permettant une odométrie précise. Cependant, sa mesure est faussée par la projection de la gravité sur l’axe sensible en fonction de l’inclinaison de la voie. L’objectif de ce mémoire est donc d’augmenter l’intérêt de ce capteur en développant une solution basée sur une centrale inertielle complète dans le but de fournir une accélération longitudinale fiable. Pour cela, un estimateur d’état a été développé à partir d’un filtre de Kalman étendu et de la prise en compte de contraintes sur le vecteur d’état. L’utilisation d’une équation de réactualisation du gain de Kalman force ainsi l’estimation d’état à évoluer dans un espace contraint. De plus, le vecteur d’observation du système a été augmenté par les informations fournies par un estimateur de vitesse et un estimateur d’attitude du train. L’estimateur de vitesse utilise une analyse fréquentielle des mesures accélérométriques et l’estimateur d’attitude exploite la complémentarité fréquentielle des mesures gyrométriques et accélérométriques pour estimer les angles de roulis et de tangage. Ces informations sont ensuite fusionnées avec les mesures de la centrale. Enfin, des expérimentations ont été réalisées en Turquie dans un train et les performances de l’estimateur ont été validées en comparant les résultats obtenus aux données fournies par une centrale de navigation haut de gamme. / The precise location of a train on the rail network is vital information for traffic management and passenger safety. The European Train Control System (ETCS) features a single-axis accelerometer which measures the longitudinal acceleration of the train. This sensor is one of many sensors onboard providing a precise odometry. However, its measurement is corrupted by the projection of the gravity on the sensitive axis as a function of the inclination of the track. The purpose of this work is to increase the value of this sensor by developing a solution based on a complete inertial system in order to provide a reliable longitudinal acceleration. For this, a state estimator was developed based on an extended Kalman filter and the consideration of constraints on the state vector. The use of updating equation of the Kalman gain forces the state estimation to evolve in a constrained space. In addition, the observation vector has been increased with the information provided by a velocity estimator and a train attitude estimator. The velocity estimator uses a frequency analysis of the accelerometer measurements and the attitude estimator operates the frequency complementarity of gyro and accelerometer measurements, to estimate the roll and pitch angles. This information is then merged with the measurements of the IMU. Finally, experiments were carried out in Turkey on a train and the estimator's performance was validated by comparing the results with data from a high-performance inertial navigation system.

Introdução: Estudos mostram a importância de quantificar a atividade física e sua associação no processo saúde-doença. Esta tarefa não é simples, principalmente em crianças, por constituir um construto multidimensional que envolve atividades realizadas no lazer, em ambientes educacionais, vinculadas à ocupação e ao transporte. O acelerômetro está em destaque nos estudos epidemiológicos com adultos e crianças nos quais existe interesse na aferição de atividade física. Objetivo: Explorar aspectos metodológicos na aferição de atividade física por meio de acelerômetro em crianças de 7 a 10 anos. Metodologia: Estudo de revisão sistemática de trabalhos selecionados segundo passos pré-definidos: critérios de inclusão dos estudos; estratégia de busca; critérios para avaliação de qualidade dos estudos identificados; informações a serem extraídas. Entre as características de interesse estão as relacionadas à tecnologia do equipamento, à utilização, à população e às medidas de aferição. Resultados: Foram localizados 872 trabalhos nas 4 bases de dados (Pubmed, Embase, SPORTDiscus, Lilacs). Foram incluídos na revisão 68 estudos com qualidade metodológica. Foi constatada a predominância de utilização de acelerômetros uniaxiais da marca Actigraph® (Modelos: GT1M; 7164), com sua maior utilização na região do quadril direito, por sete dias da semana, com epochs de duração de 60 segundos, considerando como válida a informação de 3 ou mais dias de coleta e a presença de grande variedade de pontos de corte para diferentes níveis de intensidade e desfechos da atividade física. Conclusão: O acelerômetro é bastante utilizado em pesquisas epidemiológicas na aferição de atividade física por meio de counts, uma medida que não apresenta fácil entendimento. São aspectos metodológicos que limitam a comparação entre os estudos: diferentes marcas e modelos, diferentes número de dias de observação, grande variabilidade nas faixas etárias, diferentes durações do epoch e de pontos de corte. Identifica-se a necessidade de mais estudos metodológicos para elucidar a aplicabilidade do acelerômetro como instrumento de aferição da atividade física em crianças de 7 a 10 anos / Background: Studies have shown the importance of quantifying physical activity and its association in health-disease process. This task is not easy, especially in children, because it represents a multidimensional construct that involves leisure activities, educational settings, linked to occupation and transportation. The accelerometer is frequently used in epidemiological studies with adults and children where there is interest in assessing physical activity. Objective: To explore methodological aspects in physical activity assessment using accelerometer among children aged 7 to 10 years. Methodology: Systematic literature review of studies selected according to pre-defined steps: inclusion criteria studies; search strategy, quality assessment criteria of studies identified; information to be extracted. Among the interest features, may be mentioned those related to the technology of the accelerometer, group of age and outcome measures. Results: It was found 872 papers in four databases (PubMed, Embase, SPORTDiscus, Lilacs). Were included in the review, 68 studies showed methodological quality. It was found the predominant equipament was the uniaxial accelerometers Actigraph® (Models: GT1M, 7164), frequently fixated on the right hip, seven days a week, with epochs lasting 60 seconds, for valid the information it was observed 3 or more days of collection and the presence of a large variety of cutoff points for intensity levels and physical activity outcomes. Conclusion: The accelerometer is used in epidemiological research on the assessment of physical activity considering counts as measure but it has no easy understanding. The results depend on methodological aspects that limitate the use of this equipament such as differents brands and models, fixation sites, as well as different number of days of observation, very large group of age, different epoch duration and cutoff points for outcame definition. We identified the need for more methodological studies to elucidate the applicability of the accelerometer in children aged 7 to 10 years

INTRODUÇÃO: A atividade física regular trás benefício à saúde, reduzindo a obesidade, morbidades e a mortalidade e, em pacientes asmáticos, a atividade física melhora os sintomas da doença. Apesar disso, ainda existe divergência na literatura se crianças asmáticas são fisicamente ativas, e isto parece depender do método empregado, da gravidade da doença e do controle clínico. OBJETIVO: Comparamos a atividade física de vida diária (AFVD) entre crianças com diferentes gravidades da asma e identificamos fatores que possam dificultar a realização das AFVD. MÉTODO: Estudo transversal com 121 crianças, sendo 79 asmáticas das quais (32 asma persistente leve, 24 asma persistente moderada, 23 asma persistente grave) e 42 controles, de ambos os sexos, com idade entre 7 a 12 anos. As crianças asmática estavam em tratamento médico há, no mínimo, 6 meses e com a doença controlada. O nível de AFVD foi monitorado com um acelerômetro durante 6 dias (4 dias da semana e 2 de final de semana). A função pulmonar e as barreiras que dificultam a realização da AFVD também foram avaliadas. RESULTADOS: Os nossos resultados mostraram que o número total de passos, e as atividades realizadas em intensidade moderada foram similares entre as crianças com as diferentes gravidades da asma. O percentual de crianças asmáticas fisicamente ativas foi similar quando comparado com as crianças sem asma (respectivamente, 51,9% vs. 50%; p>0,05). Não foi observada diferença nos parâmetros funcionais da função pulmonar (obstrução fixa, resposta ao broncodilatador e variabilidade do VEF1) entre as crianças asmáticas fisicamente ativas e as sedentárias (p>0,05). Porém, foi observado um maior percentual de crianças com sobrepeso ou obesidade entre os asmáticos sedentários quando comparado às crianças fisicamente ativas (respectivamente, 24,1% vs. 11,1%; p<0,05). As barreiras ambientais foram as mais relatadas pelas crianças com e sem asma (p>0,05), porém este fator foi relatado em maior proporção pelas crianças asmáticas sedentárias quando comparado àquelas fisicamente ativas (respectivamente, 34,2% vs. 14,6%; p<0,05). CONCLUSÕES: As crianças asmáticas com a doença controlada tiveram o mesmo nível de AFVD entre as diferentes gravidades da doença e que seus pares sem asma. A gravidade da doença, fatores ligados à função pulmonar e a percepção da doença como barreira para atividade física pareceu não estar associadas ao sedentarismo. As barreiras ambientais foram as mais relatadas pelas crianças com e sem asma, porém, nas crianças asmáticas sedentárias essas barreiras pareceram ser ainda mais relevantes / BACKGROUND: Regular physical activity promotes health benefits by reducing obesity, morbidity and mortality, and who has asthma, physical activity improves the symptoms of disease. Nevertheless, there is disagreement in the literature whether asthmatic children are physically active, and this seems to depend on the method used, severity of disease and clinical control. OBJECTIVE: We compared Daily Physical Activity (DPA) among children of different severity levels of asthma and we have identified factors that may hinder DPA. METHOD: Cross-Sectional study with 121 children, 79 with asthma (32 mild persistent asthma, 24 moderate persistent asthma, 23 severe persistent asthma) and 42 children without asthma, of both sexes, aged between of 7 and 12 years. The asthmatic children were under medical treatment for at least 6 months and the disease controlled. DPA was monitored with an accelerometer for 6 days (4 weekdays and 2 weekends). Pulmonary function and barriers that hinder DPA were also assessed. RESULTS: Our results showed that the total number of steps, and the activities performed at moderate intensity were similar between children with different severities of asthma. The percentage of physically active children with asthma was similar when compared with children without asthma (respectively, 51,9% vs. 50%; p>0,05). There was no difference in respiratory function parameters (fixed obstruction, bronchodilator response and variability of FEV1) among the asthmatic children physically active and sedentary (p> 0.05). However, we found that sedentary asthmatic children were more overweight or obese than physically active asthmatic children (respectively, 24,1% vs. 11,1%; p<0,05). The environmental barriers were the most frequently reported by children with and without asthma (p> 0,05), but this factor was reported in a higher proportion by sedentary asthmatic children compared to those physically active (respectively, 34,2% vs. 14,6%; p<0,05). CONCLUSIONS: Clinically controlled asthmatic children had the same level of DPA between different severities of asthma and their peers without asthma. The severity of disease, factors related to lung function and perception of disease as a barrier to physical activity did not seem be associated with sedentary lifestyle. The environmental barriers were the most frequently reported by children with and without asthma, however in sedentary asthmatic children these barriers seemed to be even more relevant