Vehicles with sensors produce large amounts of data. Transmission of data is connectedwith costs. By using data compression, less data has to be transmitted, reducing priceof operation. A number of algorithms are evaluated through tests with GPS and accelerometerdata. Performance is measured based on time usage, compression ratio,and euclidean errors (in the case of lossy compression). No algorithm or combinationof algorithms is shown to outperform the others on all data and all metrics. Threedierent recommendations are made. For lossless data compression focused on speed, acombination of Move-To-Front, Zero-Run-Length-Encoding, and Human coding is recommended.For lossless data compression focusing on compression ratio, a combinationof delta coding, Lempel-Ziv coding, and Human coding is recommended. Finally, fordata that can aord losses and that has a low amount of unique symbols, a model basedapproach is recommended.

Indiana University-Purdue University Indianapolis (IUPUI) / Various methods exist to measure physical activity (PA). Subjective methods, such as diaries and surveys are relatively inexpensive ways of measuring one’s PA; how ever, they are riddled with measurement error and bias due to self-report. Wearable accelerometers offer a noninvasive and objective measure of subjects’ PA and are now widely used in observational and clinical studies. Accelerometers record high frequency data and produce an unlabeled time series at the sub-second level. An important activity to identify from such data is walking, since it is often the only form of exercise for certain populations. While much work has been done to advance the use of accelerometers in public health research, methodology is needed for quan tifying the physical characteristics of different types of PA from the raw signal. In my dissertation, I advance the accelerometry research methodology in a three-paper sequence. The first paper is a novel application of functional linear models to model the physical characteristics of walking. We emphasize the signal processing used to prepare the data for analyses, and we apply the methods to a motivating dataset collected in an elder population. The second paper addresses the classification of PA. We designed an experiment and collected the data with the purpose of extracting useful and interpretable features for differentiating among walking, descending stairs, and ascending stairs. We build subject-specific classification models utilizing a tree based classifier. We evaluate the effects of sensor location and tuning parameters on the classification rate of these models. The third paper addresses the classification of walking types at the population level. We propose a robust normalization of features extracted for each subject and compare the model classification results to evaluate the effect of feature normalization. In summary, this work provides a framework for better use of accelerometers in the study of physical activity. / 2 years

Bakgrund: Fysisk aktivitet har flera hälsofördelar, men trots detta är en stod del av Europas befolkning inte fysiskt aktiva. Fysioterapeuter kan främja hälsa genom ökad fysisk aktivitet och ett verktyg för det är självmonitorering, vilket har framgått i systematiska litteraturöversikter. Däremot framgår inte hur självmonitoreringen har utformats, vilket begränsar dess kliniska tillämpning. Syfte: Syftet med denna studie är att sammanställa befintlig forskning för att beskriva utformningen av självmonitorering i studier som har som mål att öka fysisk aktivitet och bedöma inkluderade studiers kvalitet. Metod: En systematisk litteraturöversikt genomfördes och sju RCT-studier inkluderades efter litteratursökningar i Pubmed, Cinahl och Psycinfo. Studierna granskades utifrån examensarbetets syfte och frågeställningar samt med granskningsmall för kvalitet och preliminär evidensstyrka från SBU. Resultat: I samtliga studier kombinerades självmonitorering av fysisk aktivitet med andra beteendeförändringstekniker. Metoder var pedometer, accelerometer och självskattning som mättes med olika mått. Duration och frekvens varierade. Utvärderingsinstrumentet accelerometer och självskattning användes med flera utfallsmått. Fysiska aktivitetsnivån ökade statistiskt signifikant i fyra av studierna. Sammanvägda studiekvalitéten bedömdes som medelhög och preliminär evidensstyrka som måttligt stark. Slutsatser: Självmonitorering som intervention ökade fysisk aktivitet vid användning av pedometer med mått antal steg, i kombination med feedback och målsättning. Däremot är det osäkert att uttala sig om övrig utformning.

The stability of the Niagara Escarpment is of critical importance to residents of Hamilton, Ontario as it bisects and divides the lower downtown core from upper residential and commercial areas. The frequency of large rockfalls and debris slides from the exposed escarpment face has resulted in reoccurring road closures that connect these two areas and has prompted the city to seek information on the processes affecting escarpment erosion and slope stability. The research reported here examines the relationship between tree and plant growth on bedrock stability by investigating relationships between species abundance and slope profile, and the potential movement of tree roots growing in rock fractures. The contributing factors of tree growth to physical weathering processes on highly fractured bedrock remain largely unknown; however, plants are suggested to play a key role in weathering processes in the critical zone. Bedrock structure and lithology influence the establishment of vegetation, and vegetation in turn exploits bedrock joints, fractures, and bedding planes, exacerbating physical and biomechanical weathering processes. In this study, vegetation characteristics observed on different parts of the escarpment face were documented and categorized into three distinct biophysical zones: upper and intermediary plateau, bedrock face, and sloping talus. Tree growth, with the potential to enhance bedrock disaggregation through the transfer of tree bole movement to roots exploiting bedrock fractures, was particularly prevalent on areas of sloping talus. To document the potential for bedrock disaggregation through tree bole movement, triaxial accelerometers were mounted on the boles of three different tree species growing along the escarpment in Hamilton. Sampled trees varied in geographic location to allow identification of the relationship between tree bole movement, wind speed, and dominant wind direction. Both deciduous and coniferous species were monitored to determine the impacts of canopy architecture on tree sway in response to wind. Monitoring took place over several days in the months of March, May, September, and November. Recorded tree bole movement (tilt) varied between deciduous and coniferous tree species; wind speed was strongly correlated to tilt of the coniferous tree, and wind direction was strongly correlated to tilt of the deciduous trees. Overall tree bole movement was strongly influenced by diurnal cycles of air movement and was greatest in the hours around mid-day. The outcomes of this research will form an integral component of an erosion-risk assessment study conducted, in part, for the City of Hamilton and will facilitate the design and development of vegetation management strategies for the Niagara Escarpment that may reduce erosion processes and potential damages to impacted citizens and businesses. / Thesis / Master of Science (MSc) / This research examines the impact of vegetation growth on erosion processes on the Niagara Escarpment in Hamilton, Ontario. The slope of the escarpment face exerts an important control on vegetation growth which in turn affects slope stability. Documentation of the dominant vegetation species at two research sites allows the identification of three distinct vegetation zones on the upper plateau, bedrock face, and sloping talus. The movement of tree trunks in response to air movement was also measured for several days in the months of March, May, October and November. Results show that the movement of two monitored deciduous trees was most strongly correlated to wind direction, while the movement of a coniferous tree was strongly correlated to changes in wind speed. All monitored trees were strongly influenced by daily cycles of air movement which were greatest around noon. This research identifies factors that influence both vegetation growth and slope stability on the Niagara Escarpment and may be used to develop effective erosion protection and mitigation strategies.

PURPOSE: The primary aim of this study was to examine the accuracy of a hip (Evenson algorithm) and wrist-worn (Crouter algorithm) accelerometer in assessing time spent in different intensity categories in pre-adolescent girls during semi-structured dance classes using direct observation (D.O.) as the criterion measure. The secondary aim of this study was to examine the validity of a wrist-worn accelerometer for dichotomizing pre-adolescent girls as meeting or not meeting different preselected doses of moderate-to-vigorous PA compared to the hip-worn accelerometer. METHODS: Data were collected and analyzed on a total of 6 participants (age = 10.22 ± 2.38) for the primary aim. Additionally, data was collected and analyzed on a total of 20 participants (age = 8.6 ± 1.6) for the secondary aim. RESULTS: Compared to D.O., the wrist-worn accelerometer was inaccurate in measuring time spent in light PA, vigorous PA and MVPA. Additionally, the hip-worn accelerometer was inaccurate in measuring time spent in sedentary time, light PA, vigorous PA and total PA. Further, for the secondary aim, there was a significant difference between device location and meeting PA dosage for three days and five days. CONCLUSION: Traditional accelerometer algorithms rely on the activity count cut-point method which provides mixed to poor results of activity intensity classification regardless of wear location. Future research should move away from the activity count cut-point method and aim to develop algorithms that use more of the rich data available from the accelerometers’ acceleration signal.

The emerging technology of active RFID tags has strong potential in the areas of real time health monitoring, sorting of cargo, and large scale inventory management because of their longer communication range and larger data storage capacity. The market of active RFID is growing very rapidly and therefore there has been an increase in the number of companies engaging in this field. But very often it is found that the products available in the market are not always suited to the application at hand. To overcome this problem, off the shelf active RFID products which were reconfigurable and followed a standard PHY and MAC layer protocol were used for this work. By reprogramming the application layer protocol of the RFID hardware, these devices were made suitable for the desired application. This also allowed the RFID tags to extend their functionality by interfacing extra modules with themselves. The work presented in this thesis describes the way in which the microcontroller on board the active RFID tags and readers can be programmed so that the functionality of the RFID hardware can be changed as per requirements. It also shows that extra modules can be added to the tag by successfully interfacing an accelerometer module with the tag. / Master of Science

Vehicle classification data especially trucks has an important role in both pavement maintenance and highway planning strategy. An advanced microelectromechanical system (MEMS) accelerometer for vehicle classification based on axle count and spacing was designed, tested, and applied to the pavement. Vehicle-pavement interaction was collected by the vibration sensor while vehicle axle count and spacing were calibrated later. Collected vibration data also used to analyze the pavement surface condition and compared with simulation using dynamic loading analysis. Laboratory tests using MMLS3 device to verify the accuracy of MEMS accelerometer and reaction under different surface condition were tested. An algorithm for calculating axle spacing and axle count was developed. Acceleration of different pavement surface condition were analyzed and compared with simulation results, the influence of surface condition to the pavement acceleration was concluded. / Master of Science

Tiltmeters can be used in the mining environment to monitor slope stability by making use of gravitational force to measure angles of inclination relative to horizontal. Tiltmeters typically use accelerometers, which output a voltage measurement that can be related to angle of tilt. Though wireless tiltmeters already exist today, they lack certain ruggedness and sensitivity preventing use in mines. The purpose of this project was to investigate the feasibility of using already existing wireless tiltmeters in the mining setting. Additionally, a new wireless tiltmeter was designed which could be specially tailored for the needs of monitoring hazardous rock bodies in both surface and underground mines. By recording angles of any slope, either in a surface mine or underground, over extended periods of time, changes in readings can infer instabilities in the rock mass underlying the slope being measured. By placing many tiltmeters in a mesh on a surface slope or underground roof, rib, or other face, the entire surface can be monitored. Compared to the measurements of a single point using one instrument, a dense network can be extremely useful in detecting rock movement. Many monitoring techniques are in use already in mines. Traditional methods of monitoring, though undeniably useful, are often time consuming. By utilizing wireless devices that transmit data back to a single location, data acquisition and analysis time can be minimized, saving the mine employee hours as well as down time. As surface mines continue to deepen, and underground mines continue to progress further from the surface, the extent of necessary monitoring continues to increase: this widening range will require greater time for proper monitoring, unless an automated system is implemented. With proper wireless equipment, real time monitoring of an entire mine is possible. / Master of Science

In female college soccer players, there is no protocol for assessing fatigue. A total of 40 members of the Virginia Tech Women's Soccer team participated in the countermovement jump assessment to find a reliable way to gauge player fatigue and readiness in these athletes. These were tested by assessing the within and between-day similarity of a countermovement jump test as a measure of neuromuscular performance by comparing multiple jump heights during jumps performed within a single day and on separate days. Additionally, to determine the responsiveness of countermovement jump height as a marker of fatigue, we compared jump heights before and after activities thought to induce fatigue and competitive matches. All subjects wore a STATSports APEX unit that includes an 18Hz GPS, 952 Hz accelerometer, and 952 Hz gyroscope situated on the upper back over the second thoracic vertebra using a manufacturer-provided vest. After each training session or match, the data was downloaded using the manufacturer's software (APEXA). A custom MATLAB program was then used to calculate CMJ height from vertical acceleration. Results showed that CMJ heights were very reliable both within and between testing days. CMJ heights were found to accurately decrease following both high-load training sessions and a competitive soccer match. For both activities, the decrease in performance was dependent on the amount of load experienced. Lastly, CMJ height did not recover the day following high training load sessions. Across a training week, CMJ consistently decreased each day. This was followed by a recovery in performance following two off days. The results suggest that the use of a trunk-mounted, GPS-embedded accelerometer and a novel three-jump protocol is responsive to assess CMJ height. In addition, it is responsive to estimating fatigue following soccer activity. / Master of Science / In female college soccer players, there is no protocol for assessing fatigue. A total of 40 members of the Virginia Tech Women's Soccer team participated in the countermovement jump assessment to find a reliable way to gauge player fatigue and readiness in these athletes. We hypothesized that countermovement jump heights would not vary between jumps executed on the same day and on different days. We also hypothesized pre-training countermovement jump heights would vary across a 7-day training session with reductions dependent on the prior days' physical demands and would be reduced following a competitive soccer match, also dependent on each player's physical demands. These were tested by assessing the within and between-day reliability of a vertical jump test as a measure of performance by comparing multiple countermovement jump heights during jumps performed within a single day and comparing jumps on separate days. Additionally, to determine the feasibility of countermovement jump height as a marker of fatigue, we compared jump heights before and after activities thought to induce fatigue and competitive matches. All subjects wore a STATSports APEX unit that includes an 18Hz GPS, 952 Hz accelerometer, and 952 Hz gyroscope situated on the upper back over the second thoracic vertebra using a manufacturer-provided vest. After each training session or match, the data was downloaded using the manufacturer's software (APEX) and a custom MATLAB program was then used to calculate CMJ height from vertical acceleration. Results showed that CMJ heights were very reliable both within and between testing days. CMJ heights were found to decrease following both high-load training sessions and following a competitive soccer match. For both activities, the decrease in performance was dependent on the amount of load experienced. Lastly, CMJ height did not recover the day following a high training load sessions. Across a training week, CMJ consistently decreased each day. This was followed by a recovery in performance following two off days. The results suggest that the use of a trunk-mounted, GPS-embedded accelerometer and a novel three-jump protocol is reliable to assess CMJ height. In addition, it is feasible to estimating fatigue following soccer activity.

Bakgrund Barn med fetma har lägre fysisk aktivitetsnivå än normalviktiga barn. Låga nivåer av fysisk aktivitet vid ung ålder leder ofta till låga nivåer av fysisk aktivitet som vuxen, vilket ger ökad risk för metabola syndromet. Ökad fysisk aktivitet ger ökad AEE och kan leda till ökad FFM, vilket hjälper till att höja TEE som är viktigt vid långsiktig viktminskning. Syfte Syftet med studien var att undersöka skillnad i total energiförbrukning, TEE, och aktivitetsrelaterad energiförbrukning, AEE, uppmätt med accelerometer på barn med övervikt eller fetma vid inskrivning, jämfört med efter minst ett år. Syftet var också att se om det var någon skillnad inom respektive kön i total och aktivitetsrelaterad energiförbrukning samt om det fanns något samband mellan dessa med förändring i kroppssammansättningen. Metod Data från två undersökningstillfällen där 28 barn genomfört mätning av BMR, kroppssammansättning och aktivitetsutredning med accelerometer samlades in. Jämförande statistik mellan undersökningstillfällena genomfördes på energiförbrukningsvariablerna TEE och AEE. Resultat TEE hade minskat (p=<0.01) och AEE hade minskat (p=<0.01) vid årskontrollen. Resultatet för respektive kön visade för pojkar att det var en skillnad mellan undersökningstillfällena i både TEE (p=0.004) och AEE (p=0.009). För flickor var det en skillnad i TEE (p=0.005) men inte i AEE (p=0.091). Det fanns en korrelation mellan TEE och FM (r=-0,47, p=0,014), och FFM (r=0,47, p=0.014) i procent. Slutsats Barnen i denna studie hade lägre TEE och AEE ett år efter de blivit inskrivna på överviktsenhet samtidigt som de blivit mer överviktiga. Med tanke på studiegruppens storlek bör detta resultat tolkas med försiktighet. / Background Children with obesity have a lower level of physical activity than normal weight children. Low levels of physical activity at a young age suggests low levels of physical activity as an adult, which increases the risk of the metabolic syndrome. Increased physical activity increases AEE and can lead to increased FFM which helps to increase TEE which is important for long term weight loss. Aim The aim of this study was to examine difference in total energy expenditure, TEE, and activity-related energy expenditure, AEE, measured by accelerometer on children with obesity at enrolment, compared to at least a year later. Furthermore, the aim was to see if there was any difference within each gender in total and activity-related energy expenditure and if there was any correlation between these with the change in the body composition. Method Data from two examinations where 28 children completed measurements of BMR, body composition, and activity registration with accelerometer was collected. Comparative statistics between the examinations were carried out on the energy consumption variables TEE and AEE. Results TEE has decreased (p=<0.01) and AEE has decreased (p=<0.01) at the year follow up. The result for each gender showed for the boys that there was a difference between the examinations in both TEE (p=0.004) and AEE (p=0.009). While for girls there was a difference in TEE (p=0.005) but not in AEE (p=0.091). There was a correlation between TEE and FM (r=-0.47, p=0.014), and FFM (r=0.47, p=0.014) in percent. Conclusion The children in this study had lower TEE and lower AEE one year after they were enrolled at the obesity unit while they have become more obese. Considering the size of the study group this result should be interpreted with caution.