Intelligent devices such as smart phones, smart watches, virtual reality (VR) headsets and personal exercise devices have become integral elements of accessories used by many people. The ability of these devices to verify or identify the user could be applied for enhanced security and user experience customization among other things. Almost all these devices have built-in inertial sensors such as accelerometer and gyroscope. These inertial sensors respond to the movements made by the user while performing day to day activities like walking, getting up and sitting down. The response depends on the activity being performed and thus can be used for activity recognition. The response also captures the user's unique way of doing the activity and can be used as a behavioral biometric for verification or identification. The acceleration (accelerometer) and rate of rotation (gyroscope) are recorded in the device coordinate frame. But to determine the user's motion, these need to be converted to a coordinate frame relative to the user. In most situations the orientation of the device relative to the user can neither be controlled nor determined reliably. The solution to this problem requires methods to remove the dependence on device orientation while comparing the signals collected at different times. In a vast of majority of research to date, the performance of authentication algorithms using inertial sensors have been evaluated on small datasets with few tens of subjects, collected under controlled placement of the sensors. Very often stand alone inertial sensors have been used to collect the data. Stand alone sensors afford better calibration, while the sensors built into smart devices offer little or no means of calibration. Due to these limitations of the datasets used, it is difficult to extend the results from these research to realistic performance with a large number subjects and natural placement of off-the-shelf smart devices. This dissertation describes the Kabsch algorithm which is used to achieve orientation invariance of the recorded inertial data, enabling better authentication independent of device orientation. It also presents the Vector Cross Product (VCP) method developed to achieve orientation invariance. Details of a realistic inertial dataset (USF-PDA dataset) collected with commercial smart phones placed in natural positions and orientations using 101 subjects are given. The data includes sessions from different days on a subset of 56 subjects. This would enable realistic evaluation of authentication algorithms. This dataset has been made publicly available. The performance of five methods that address the orientation dependence of signals are compared to a baseline that performs no compensation for orientation of the device. The methods as a part of a overall gait authentication algorithm are evaluated on the USF-PDA dataset mentioned above and another large dataset with more than 400 subjects. The results show that the orientation compensation methods are able to improve the authentication performance on data with uncontrolled orientation to be close to performance on data collected with controlled orientation. The Kabsch method shows the highest improvement.

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.

<p>Free2Move AB is developing products for the market within wireless communication</p><p>and identification, among those active RFID-tags. The company had an idea about</p><p>providing one of their active RFID tags with a GPS receiver and transmit positions via</p><p>an existing RFID protocol. Desire from the company was also the possibility to log</p><p>positions and measure temperature. The finished prototype should also be able to be</p><p>activated by movement. The company had proposal about components that were to be</p><p>used in the project. A large part of the work was to understand how these worked and</p><p>how to combine them to fulfill the requirements established in agreement with</p><p>supervisor at Free2Move. A PIC microcontroller was used in the design of the prototype</p><p>and software implemented for communication with GPS, RFID tag and other</p><p>components. The result was a working prototype where an existing RFID tag was</p><p>integrated in the same printed circuit board layout as the GPS receiver and other</p><p>components that were used in the project.</p>

Purpose: To examine the relationship between hand rim propulsion power and energy expenditure during wheelchair locomotion. Methods: Fourteen individuals who used manual wheelchairs were included in this study. Each participant performed five different locomotion activities in a wheelchair with a PowerTap hub built into the rear wheel. The activities included wheeling on a level surface that elicited a low rolling resistance at three different speeds (4.5, 5.5, and 6.5 km∙hr-1), wheeling on a rubberized 400m track that elicited a higher rolling resistance at one speed (5.5 km∙hr-1), and wheeling on a sidewalk course that included uphill and downhill segments at their self-selected speed. Energy expenditure was measured using a portable indirect calorimetry system. In addition, each subject wore an Actical and a SenseWear activity monitor on the right wrist and upper arm, respectively. Stepwise, linear regression was performed to predict energy expenditure from power output variables. A repeated measures ANOVA was used to compare the measured energy expenditure to the estimates from the power models, the Actical, and the SenseWear. Bland-Altman plots were used to assess the agreement between the criterion values and the predicted values. Results: The relationship between energy expenditure and power was significantly correlated (r = 0.694, p < 0.001). Stepwise, linear regression analysis yielded three significant prediction models utilizing measured power; measured power and speed; and measured power, speed, and heart rate. A repeated measures ANOVA demonstrated a significant main effect between measured energy expenditure and estimated energy expenditure (p < 0.01). There were no significant differences between the criterion method and the power models or the Actical. The SenseWear significantly overestimated energy expenditure when wheeling at 4.5 km·hr-1, 5.5 km·hr-1, 6.5 km·hr-1, and during self-paced sidewalk wheeling (p < 0.05). Conclusion: Energy expenditure can be accurately and precisely estimated based on wheelchair propulsion power. These results indicate that wheelchair power could be used as a method to assess physical activity in people who use wheelchairs.

Med ökat miljömedvetande från transportbolag har även ökad uppföljning på förarnas körbeteende kommit mer och mer. Man försöker förbättra förarnas beteende för att minska förbrukningen av drivmedel. När det gäller kollektivtrafiken påverkar förarnas körbeteende inte enbart förbrukningen utan även passagerarnas komfort. För att förbättra komforten har önskemål om möjligheter till uppföljning uppkommit. Denna rapport beskriver framtagningen av en accelerationsmeter för bussar. Systemet kan mäta och lagra g-krafter från en accelerationssensor som sedan ska skickas till en dator i fordonet. Mätningar görs längs tre axlar för att ge en så komplett bild av händelseförloppet som möjligt. Syftet med systemet är att förbättra komforten för passagerarna ombord på bussarna samtidigt som man kan konstatera vägavsnitt eller förare som har stor positiv eller negativ inverkan på komforten. För att kunna utvärdera förarnas körbeteende krävs det verktyg för en rättvis uppföljning. Detta projekt har tagit fram tre modeller för presentation av data som kan användas till detta ändamål.

Syfte Syftet med studien var att undersöka hur energibalansmätning och aktivitetsregistrering med indirekt respiratorisk kalorimetri, accelerometer, kostdagbok och aktivitetsdagbok, uppfattades av överviktiga barn och tonåringar och att jämföra uppfattningarna mellan barn i olika åldrar och av olika kön.   Metod 129 överviktiga barn valdes ut med ett konsekutivt urval då de kom för energibalansmätning på Energimetaboliska laboratoriet vid Uppsala Universitet mellan 2008 och mars 2012. En enkät fylldes i av barnen efter att de genomgått en mätdag på laboratoriet samt fyra mätdagar självständigt i hemmet. Enkäten innehöll elva frågor varav tio frågar handlade om de olika mätmetoderna som barnen genomgått. Författarna koncentrerade sig på fyra av dessa mätmetoder. Frågorna besvarades med hjälp av femgradiga skalor, varav resultaten sammanställdes för en statistisk analys.   Resultat Huvudresultatet visade att alla fyra mätmetoder uppfattades någorlunda likvärdigt av barnen, oavsett kön. Dock kunde det påvisas att den yngre åldersgruppen (4-9 år) överlag hade tendenser till en positivare uppfattning av mätmetoderna än barnen i åldrarna 10-13 och 14-17 år. Ingen signifikans kunde påvisas från de olika resultaten.   Slutsats Sammanfattningsvis framkom att ett behov av förbättring för vissa av mätinstrumenten fanns. Resultatet visade också att det fanns ett behov för effektivisering av vissa mätmetoder, ny design för instrumenten samt hjälpmedel för att uppnå bra registrering av kost och aktiviteter.

Syfte och frågeställningar Huvudsyftet med denna studie är att validera enkätfrågor om fysisk aktivitet från Skola-Idrott-Hälsa studien med hjälp av accelerometern GT3X. Vidare är ett syfte att problematisera de båda datainsamlingsmetoderna. Hur valid är den självskattade SIH-enkäten för vuxna när det gäller att mäta fysisk aktivitet? Hur väl korrelerar de utvalda frågorna från SIH-enkäten med accelerometern GT3X? Metod Studien är genomförd med accelerometer och enkät som mätmetoder för att mäta fysisk aktivitet. Enkätfrågorna är utvalda från en enkät som använts till unga vuxna i Skola-Idrott-Hälsa studien. De 49 deltagarna har fått besvara enkäten, samt burit en accelerometer av modellen GT3X under en vecka. Ett flerstegsurval, med ett bekvämlighetsurval har skett. Gruppen bestod av 24 män och 25 kvinnor i åldern 20-45 år. Deltagarna fick bära accelerometern under dygnets alla vakna timmar med hjälp av ett elastiskt band som fästes på höften. Accelerometern var inställd att mäta över en axel, med ett tidsintervall på 15 sekunder. Enkäten poängsattes efter ett eget utformat poängsystem för att kunna korreleras mot den insamlade datan från accelerometern. Poäng från enkäten behandlades dels som kontinuerlig data och i grupper indelat i tertiler. Data från accelerometern analyserades som andel av den registrerade tiden som spenderades i stillasittande samt i moderat till intensiv fysisk aktivitet (MVPA).  Analyser har gjorts med hjälp av Spearmans korrelation. Resultat Korrelationer visar svaga men signifikanta värden mellan den totala poängen från enkäten och intensitetsnivåerna sedentärt och medel till intensiv nivå. 57 procent av deltagarna uppger att de sitter stilla mer än sju timmar under vardagar, och 49 procent under helgdagar. Medelvärdet för gruppen visar att deltagarna befinner sig 72 procent på sedentär intensitetsnivå och 6 procent i medel till intensiv nivå av den tiden som accelerometern burits. Slutsats Korrelationen av enkäten och accelerometern visar att enkätfrågorna kring fysisk aktivitet ger låga värden mot intensitetsnivåerna sedentärt och MVPA, vilket tyder på att enkäten har låg validitet. Det som fascinerat oss mest är hur svårt det är att självskatta sin tid i stillasittande och hur lätt det är att överskatta sin tid på högintensiv nivå.

This paper presents the research on the robust control of micromachined accelerometers. First, we present different micromaching techniques and compare, analyze the accelerometers with different methods of signal pick-off. Besides the different methods of signal pick-off(the position detection of the seismic mass) and structure designs, we can enhance the performance such as stability, bandwidth, sensitivity, resolution and dynamic range etc. by suitable feedback controllers. So inside the front part of the paper are the analyses for the controllers of different types of accelerometers so far. Moreover, we design the controllers by robust control in different methods with the model of one specific type of micromachined tunneling accelerometer. Because of the robust controllers, the accelerometers can be stable and have good performance under different environments and uncertainties. At last we analyze and compare the controllers designed by -synthesis and gap metric.

<p>Med ökat miljömedvetande från transportbolag har även ökad uppföljning på förarnas körbeteende kommit mer och mer. Man försöker förbättra förarnas beteende för att minska förbrukningen av drivmedel. När det gäller kollektivtrafiken påverkar förarnas körbeteende inte enbart förbrukningen utan även passagerarnas komfort. För att förbättra komforten har önskemål om möjligheter till uppföljning uppkommit.</p><p>Denna rapport beskriver framtagningen av en accelerationsmeter för bussar. Systemet kan mäta och lagra g-krafter från en accelerationssensor som sedan ska skickas till en dator i fordonet. Mätningar görs längs tre axlar för att ge en så komplett bild av händelseförloppet som möjligt. Syftet med systemet är att förbättra komforten för passagerarna ombord på bussarna samtidigt som man kan konstatera vägavsnitt eller förare som har stor positiv eller negativ inverkan på komforten.</p><p>För att kunna utvärdera förarnas körbeteende krävs det verktyg för en rättvis uppföljning. Detta projekt har tagit fram tre modeller för presentation av data som kan användas till detta ändamål.</p>

Free2Move AB is developing products for the market within wireless communication and identification, among those active RFID-tags. The company had an idea about providing one of their active RFID tags with a GPS receiver and transmit positions via an existing RFID protocol. Desire from the company was also the possibility to log positions and measure temperature. The finished prototype should also be able to be activated by movement. The company had proposal about components that were to be used in the project. A large part of the work was to understand how these worked and how to combine them to fulfill the requirements established in agreement with supervisor at Free2Move. A PIC microcontroller was used in the design of the prototype and software implemented for communication with GPS, RFID tag and other components. The result was a working prototype where an existing RFID tag was integrated in the same printed circuit board layout as the GPS receiver and other components that were used in the project.