Context: Sensor base data is being used for many purposes in designing various memory aid systems for cognitive impaired people. Different memory aids or reminder systems are based on various technologies such as NFC, accelerometer, GPS and gyroscope. Smart phones are equipped with such sensors and can be used for assistance of persons. In this study we use smart phone sensors in order to design a context aware reminder system to assist cognitive impaired people. Objectives: Different reminder systems, needs for such systems, technologies and models used to build a reminder system are identified in this research work. Ultimate goal of the study is to assist cognitive people in their daily life activities, using available embedded technologies of smart phones. Following objectives were set to achieve the goal of the thesis work: • What are reminder systems and why do we need such systems? • What are the different kinds of technologies reported in literature for reminder systems? • What are the issues encountered by cognitive impaired/elderly people while performing their daily life activities? • How to design and implement context aware reminder system using Smartphone embedded sensors? Methods: Mix method approach is used to carry out this study. Literature review is conducted based on the notion of systematic review. Data is collected through survey and interviews, conducted in south Sweden municipality, to analyze and indentify daily life issues and problems of cognitive people. Experiments are performed in real environment to test and verify our application. We evaluate the performance of activity recognition algorithm, implemented in the application, using Weka. Results: Various reminder systems, their needs and underlined technologies are identified and reported. Activities of daily living and issues addressed by these reminder systems are also identified. Survey and interviews help us to identify issues and problems faced by cognitive impaired/elderly while performing their daily life activities. For example, we find out that cognitive people not only forget their daily life activities but also during performing these activities. Conclusions: Many proposed models in literature are related to each other and use similar sensor based data from various technologies. Based on literature review, survey and interviews we have concluded that context based reminder system is essential for cognitive disabled people. It leads us to design a context based reminder system for android based smart phones. The preliminary tests help us to verify our model but there is absolute need for further empirical verification and validation.

Every smartphone today includes an accelerometer. An accelerometer works by detecting acceleration affecting the device, meaning it can be used to identify incidents such as collisions at a relatively high speed where large spikes of acceleration often occur.A gyroscope on the other hand is not as common as the accelerometer but it does exists in most newer phones. Gyroscopes can detect rotations around an arbitrary axis and as such can be used to detect critical rotations.This thesis work will present an algorithm for utilising the accelerometer and gyroscope in a smartphone to detect incidents occurring on a test track for cars. / Alla smarta telefoner innehåller idag en accelerometer. En accelerometer analyserar acceleration som påverkar enheten, vilket innebär att den kan användas för att detektera incidenter så som kollisioner vid relativt höga hastigheter där stora spikar avacceleration vanligtvis påträffas. Ett gyroskop däremot är inte lika vanlig som en accelerometer men finns i de flesta nyare telefoner. Ett gyroskop kan detektera rotationer runt en godtycklig axel och kan på så vis användas för att detektera kritiska rotationer. Detta examensarbete kommer att presentera en algoritm för att utnyttja accelerometern och gyroskopet i en telefon för att detektera incidenter som inträffar på en testbana för bilar.

Background: Chronic neck pain is a problem that may be prevented and treated by physical activity. Little is known about effective interventions to increase physical activity in workers with neck pain. Objective: To evaluate the effects of an intervention aimed at increasing physical activity among workers with chronic neck pain. Design: A 10-week randomized controlled study in a population of 35 (intervention n= 19, control n= 16) workers. Physical activity was assessed using a tri-axial accelerometer pre and post the intervention. Outcomes: Daily steps, metabolic equivalent, proportions of time spent sitting/lying, standing and walking, and sit-to stand transitions. Linear mixed model was used to analyze the intervention effect (group × time) adjusted for the baseline value for each outcome. Results: There was no significant intervention effect on steps, metabolic equivalent, walking or sit-to stand transitions. There were significant intervention effects on decreased time spent sitting/lying (p=0.010) and increased standing (p=0.017).   Conclusion: No differences between intervention and control groups were found in parameters of total physical activity. However sedentary time decreased substantially in intervention group and was replaced by standing time. Larger studies using objective assessments of physical activity and sedentary behavior, investigating the effects of changes in PA and sedentary behavior on pain and health outcomes, in a working population with chronic neck pain are recommended. / Bakgrund: Kronisk nacksmärta är ett problem som kan vara möjligt att förebygga och behandla med fysisk aktivitet. Det finns begränsad kunskap om effektiva interventioner för att öka fysisk aktivitet hos arbetstagare med nacksmärta. Syfte: Att utvärdera effekten av en intervention riktad mot att öka fysisk aktivitet hos en grupp arbetstagare med kronisk nacksmärta. Design: En 10 veckors randomiserad kontrollerad studie i en population av arbetstagare med kronisk nacksmärta, n= 35 (interventionsgrupp n=19, kontrollgrupp n= 16). Fysisk aktivitet mättes med triaxiell accelerometer före och efter interventionen.  Utfallsmått: Antal steg per dag, metabolisk ekvivalent, förändringar i proportionerna mellan tid i sittande/liggande, stående och gående och antal uppresningar från sittande till stående. Resultat: Det fanns ingen signifikant interventionseffekt avseende steg, metabolisk ekvivalent, tid i gående eller antal uppresningar från sittande. Tid i sittande/liggande minskade signifikant (p=0,010) och tid i stående ökade, också signifikant (p=0,017).  Slutsats: Det fanns ingen skillnad mellan grupperna i total fysisk aktivitet. Däremot minskade tiden i sittande/liggande markant och ersattes av tid i stående. Större studier med objektiva mätningar av fysisk aktivitet och stillasittande beteende som också undersöker effekter av förändringar i fysisk aktivitet på smärta och hälsovariabler bland arbetstagare med kronisk nacksmärta rekommenderas. / STIMUL

To explore soil conditions at sites of infrastructure projects a number of geotechnical soundings are performed at appropriate intervals. Results are, in the nature of their set up, limited to the specific points at which the sounding is performed. To safely assume the area between bore holes a new method is applied and tried at the case railroad project Stenkumla – Dunsjö. By applying vibration theory in conjunction with the studied soils’ geodynamic properties the natural frequency for the soil can be calculated. The properties of the natural frequency also makes it possible to detect in vibration measurements. The method studied in this master thesis is that of utilizing the natural frequency of the soil to try and establish a soil profile from vibration measurements.  An important step in the method is to transform the vibration with the Fast Fourier Transform algorithm. This allows the comparison and analysis of natural frequencies. The measurements were performed by using and attaching an accelerometer to a train.  Results are partly transformed measurement data in frequency graphs and partly natural frequency calculations according to the site investigations. These are compared in the analysis section to try to confirm the methods’ reliability and to see if the method can be used to refine geotechnical investigations.  The reliability of the method is tested by watching for the expected frequencies from the calculations in the measurement data.  The method show more consistency closer to the ground surface rather at greater depths. It is also more reliable for stark contrast layers, i.e. if the soil layers have much of the same properties then it is difficult to spot the differing natural frequencies, as they are too similar.  In trying to establish the soil profile between bore holes the method is inconclusive, partly due to the fact that the investigated area consists of relatively alike soil layers that make the result graphs difficult to get information from. However, the suggested soil profiles from the analysis of this part of the master thesis bear resemblances to bore holes close by, so the method can be usable in some regard. Quality of measurement results would probably be better by running the train faster than was done in this master thesis. The quality of the analysis would also benefit from performing specific soundings to establish the soils’ geodynamic properties rather than using recommended empirical formulas as were used here.  The primary possible application for this method is to use it as a prioritizing tool at an early stage in infrastructure projects. Running the vibration measurement and getting a preliminary picture of the soil conditions could act as a way of steering investigations resources to where greater shifts in the data occur. / I det förberedande skedet inför infrastrukturprojekt genomförs geotekniska undersökningar för att kartlägga jordförhållanden. Detta genomförs bland annat med ett antal olika borrhålsmetoder. Genom sin utförandeform levererar dessa resultat som, strikt uttryckt, är knutna till de specifika punkter där de utförs. I detta examensarbete provas en ny metod där jordprofilen mellan- och vid punkten för borrhål ska kartläggas. Metoden provas ut på järnvägsprojektet Stenkumla – Dunsjö.  Vibrationsteori och geodynamiska egenskaper hos jorden utnyttjas för att fastställa olika jordlagers egenfrekvens. Egenfrekvensens definition gör det möjligt att detektera denna i vibrationsmätningar. Metoden som provas i examensarbetet är att genom vibrationsmätningar fastställa jordprofilen baserat på jordlagrens egenfrekvens.  Ett viktigt steg i metodens process är att transformera resultatet från vibrationsmätningen med Fast Fourier Transformation, en algoritm för databehandling. Genom att applicera Fast Fourier Transformation kan en jämförelse mellan egenfrekvenser från olika källmaterial göras.  De primära vibrationsmätningarna genomfördes genom att fästa en accelerometer på ett tåg. Resultat består i transformerade grafer från vibrationsmätningar samt egenfrekvensberäkningar baserade på de geotekniska undersökningarna vid projekt Stenkumla – Dunsjö. På detta följer en jämförande analys där metodens tillförlitlighet och applicerbarhet runt geotekniska undersökningar diskuteras.  Tillförlitligheten testas genom att identifiera beräknade förväntade värden på egenfrekvensen i mätdatat från tåget. Metoden visar högre tillförlitlighet närmare markytan än djupare ner i jordprofilen. Metodens precision är mer utvecklad för jordprofiler där jordlagren är differentierade från varandra i dess egenskaper. Detta uppstår som en följd av att mer lika drag hos jordlagren får liknande egenfrekvens, vilket gör dem svårare att identifiera och särskilja i frekvensspektrat.  Metoden visade sig vara ofullständig i att fastställa en jordprofil mellan geotekniska borrprover. En anledning till detta är att det område som användes för vibrationsmätningar består av en jordprofil utan allt för varierande egenskaper, vilket gör att en tillräckligt tillförlitlig analys är omöjlig med den mängd data som fanns att tillgå. Den jordprofil som itererades fram i analysavsnittet har dock liknande uppbyggnad som de jordprofiler som fastställts av geotekniker i den geotekniska undersökningsrapporten, vilket ändå tyder på viss användningspotential. Kvalitén på vibrationsmätningen skulle förbättras av att öka farten, och så vibrationen, på tåget som mätaren var fäst på. En annan förbättringsmöjlighet är att få tillgång till uppmätta geodynamiska egenskaper hos jorden istället för de empiriska formler som användes i detta arbete.  Det primära användningsområdet för metoden är att använda den som ett prioriteringsverktyg i ett tidigt skede vid infrastrukturprojekt. Genom att genomföra en vibrationsmätning kan en preliminär bild av jordförhållandena erhållas. Detta kan sedan användas som ett sätt att styra geotekniska undersökningsresurser mer effektivt mot områden där stora avvikelser i vibrationsdatat identifierats.

This report describes the manufacture and control of a flying platform. The report describes the basic and fundamental theories required to get the platform flying. It touches on subjects such as A/D-conversion. PWM-control and PID-control. The sensors used in the platform are a gyro and an accelerometer. The platform is controlled from a ground station through a wireless link. The wireless link is an Xbee-module that implements the ZigBee-protocol. The microprocessor used is the Atmega 128 by Atmel. An indirect complementary filter is used to get the angle of the platform. For the platform to be able to balance a more thourough analysis of the gyro is required. This sensor proved to be more difficult to handle than first anticipated. Every component except the gyro worked as expected. Every algorithm and method reported in this work have been implemented and tested in software.

This thesis explains the design, fabrication and characterization steps of a high dynamic range CMOS-MEMS capacitive accelerometer array and on-chip environmental sensors for bias drift compensation. Inertial navigation under harsh environments requires a high dynamic range accelerometer that can survive and provide continuous readout accuracy through shock events, while having a large dynamic range to capture fine-scale motions. The dynamic range target is set as 156 dB in accordance with navigation standard macro-electromechanical accelerometers, which corresponds to around 1 mG acceleration resolution in 50 kG input range. The small accelerometer cell design ensures shock survivability (e.g. up to 50 kG) by keeping the stress at the anchors below the fracture strength of thin-film oxide. Arraying multiple accelerometer cells in parallel lowers the fundamental thermomechanical noise limit set by the small mass of the individual accelerometer cells. Resonance frequency staggering between accelerometer cells suppresses ring-down oscillations. Parasitic capacitance of the high-impedance transduction signal is important to mitigate; undercut of the underlying silicon substrate and an aluminum etch of the top metal layer, incorporated in the CMOS-MEMS process flow, reduces the parasitic capacitance and improves sensitivity. PTAT temperature sensors, piezoresistive stress sensors and resonator-oscillators integrated across the accelerometer chip provide high-resolution environmental measurements for the compensation of long-term bias and scale factor drift. Simultaneous measurements from the accelerometer and environmental sensors demonstrate the correlation between environmental variations and long-term drift. Finite-element analysis shows that the scale factor stability of the accelerometer can be improved up to 1 ppm given the sensor array’s measurement resolution. The CMOS-MEMS accelerometer system-on-chip is fabricated in a TowerJazz 0.18 μm CMOS process. The post-CMOS MEMS processing steps are tuned to reduce the top metal milling and sidewall polymer deposition. A reactive ion etch recipe is developed for the removal of the top metal in order to reduce the parasitic capacitance and eliminate the risk of metal creep at spring beam anchors, thereby improve the bias stability. The PTAT temperature sensors have 3.1 mV/K measured sensitivity and 7.1 mK resolution with high repeatability. The compensation of the accelerometer readout for temperature variations down to 7.1 mK translates to 2.6 ppm scale factor stability for the accelerometer. The characterization of the stress sensors through the application of normal stress on the device package leads to an uncertainty in the amount of stress transferred to the stress sensors on the chip surface. The maximum measured stress sensitivity is 36.5 pV/Pa, which leads to 24.7 kPa stress resolution and translates to 1.7 ppm scale factor stability for the accelerometer without taking the stress attenuation into account. The measured sensitivity sets a lower bound on the sensitivity of the stress sensors implying that the stress resolution and the corresponding accelerometer scale factor stability is higher in practice. The measured frequency stability of the resonator-oscillator is 0.4 ppm, thereby the resonance frequency based variations of the accelerometer readout can be compensated to reach up to 0.8 ppm scale factor stability. However, the initial drift in the resonance frequency of the oscillators due to dielectric charging requires a long wait-time before these sensors can be used for accelerometer drift compensation. The accelerometer array is demonstrated to have 23.7 mG/√Hz noise floor and 70 mG bias stability. The maximum input acceleration applied on the device is limited to 4 kG by the split Hopkinson bar test setup. Improvement of the setup to transfer acceleration amplitudes up to 50 kG should validate the designed input range of the accelerometer array and lead to 117 dB dynamic range for the current design. The measurement bandwidth is fundamentally set by the 126 kHz resonance frequency of the accelerometer cells and can be further limited by filtering the readout signal to attenuate the transient oscillations faster. The nonlinearity of the accelerometer response is better than 1.2% in ±10 kG input range; however, it gets up to 19.0% in ±50 kG maximum input range. The long term bias drift of the accelerometer is shown to be correlated with the temperature and stress variations. Compensation of the accelerometer readout based on the stress and temperature sensor measurements leads to an observable improvement in the long term drift. However, the bias stability of the accelerometer is limited by excessive flicker noise in the system, which is believed to result from noise folding from higher frequencies. Suppression of the flicker noise in the system should allow for a more detailed study of the effect of environmental variations on the accelerometer readout and evaluation of more elaborate fitting algorithms for model based prediction and compensation of the bias drift to reach the target bias stability and dynamic range.

Abstract This dissertation aimed at developing a multi-modal sensing u-healthcare system (MSUS), which reflects the unique properties of a healthcare application in a wireless sensor network. Together with health parameters, such as ECG, SpO2 and blood pressure, the system also transfers context-aware data, including activity, position and tracking data, in a wireless sensor network environment at home or in a hospital. Since packet loss may have fatal consequences for patients, health-related data are more critical than most other types of monitoring data. Thus, compared to environmental, agricultural or industrial monitoring, healthcare monitoring in a wireless environment imposes different requirements and priorities. These include heavy data traffic with wavelike parameters in wireless sensor network and fatal data loss due to the traffic. To ensure reliable data transfer in a wireless sensor network, this research placed special emphasis on the optimization of sampling rate, packet length and transmission rate, and on the traffic reduction method. To improve the reliability and accuracy of diagnosis, the u-healthcare system also collects context-aware information on the user’s activity and location and provides real-time tracking. Waveform health parameters, such as ECG, are normally sampled in the 100 to 400 Hz range according to the monitoring purpose. This type of waveform data may incur a heavy burden in wireless communication. To reduce wireless traffic between the sensor nodes and the gateway node, the system utilizes on-site ECG analysis implemented on the sensor nodes as well as query architecture. A 3D VRML viewer was also developed for the realistic monitoring of the user’s moving path and location. Two communication methods, an 802.15.4-based wireless sensor network and a CDMA cellular network are used by sensors placed on the users’ bodies to gather medical data, which is then transmitted to a server PC at home or in the hospital, depending on whether the sensor is within or outside the range of the wireless sensor network.

A Wearable Mobility Monitoring System (WMMS) can be an advantageous device for rehabilitation decision-making. This thesis presents the design and evaluation of a proof-of-concept WMMS that uses the BlackBerry Smartphone platform. A Java program was developed for the BlackBerry 9550, using the integrated tri-axial accelerometer, Global Positioning System sensor (GPS), CMOS digital video camera, and timer to identify change-of-state (CoS) among static states, dynamic states, small activity of daily living (ADL) movements, and car riding. Static states included sitting, lying, standing, and taking an elevator. Dynamic states included walking on level ground, walking on stairs, and walking on a ramp. Small activity of daily living movements included bathroom activities, working in the kitchen, and meal preparation. Following feature extraction from the sensor data, two decision trees were used to distinguish CoS and mobility activities. CoS identification subsequently triggered video recording for improved mobility context analysis during post-processing.

Le test et la calibration des MEMS sont des enjeux complexes à cause de leur nature multi-domaines. Ils nécessitent l'application de stimuli physiques, en utilisant des équipements de test coûteux, afin de tester et de calibrer leurs spécifications. L'objectif de cette thèse est de développer des méthodes alternatives et purement électriques pour tester et calibrer un accéléromètre MEMS convectif. Premièrement, un modèle comportemental du capteur est développé et validé en se basant sur des simulations FEM. Il inclut l'influence de tous les paramètres géométriques sur la sensibilité du capteur. Deuxièmement, le modèle est utilisé pour simuler des fautes dans le but d'identifier la corrélation qui peut exister entre la sensibilité du capteur à l'accélération et certains paramètres électriques. Troisièmement, cette corrélation est exploitée pour développer des méthodes de test et de calibration alternatives où la sensibilité est estimée en effectuant uniquement des mesures électriques et sans appliquer de stimuli physiques (accélérations). L'efficacité de ces méthodes est ainsi démontrée. Finalement, deux architectures permettant l'auto-test et l'auto-calibration sur puce sont proposées. / MEMS test and calibration are challenging issues due to the multi-domain nature of MEMS devices. They therefore require the application of physical stimuli, using expensive test equipments, to test and to calibrate their specifications. The main objective of this thesis is to develop alternative electrical-only test and calibration procedures for MEMS convective accelerometers.First, a behavioral model that includes the influence of sensor geometrical parameters on sensitivity is developed and validated with respect to FEM simulations. Second, the model is used to perform fault simulations and to identify correlation that may exist between device sensitivity to acceleration and some electrical parameters. Third, this correlation is exploited to develop alternative test and calibration methods where the sensitivity is estimated using only electrical measurements and without applying any physical stimulus (acceleration). The efficiency of these methods is demonstrated. Finally, two architectures that allow on-chip test and calibration are proposed.

Les capteurs de type MEMS (Micro Electro Mechanical Systems) sont des microsystèmes mettant en œuvre différents domaines de la physique (électronique, mécanique, chimie, optique,...) et permettant de mesurer différentes grandeurs physiques (accélération, pression, température...). Parmi ces micro-capteurs, les MEMS vibrants se caractérisent par leur structure présentant un micro-résonateur mis en vibration à sa fréquence de résonance et la variation de cette fréquence est représentative du mesurande. Cette thèse s'intéresse principalement à analyser et identifier les limites de résolution fréquentielle de ces capteurs vibrants en effectuant une modélisation multiphysique. Dans un premier temps, nous avons modélisé le comportement multiphysique d'un capteur MEMS vibrant en détaillant trois types de transduction (piézoélectrique, électrostatique et optique). La seconde partie a permis de valider les équations développées en se basant sur les simulations sous Cadence (langage multiphysque Verilog-A) et en les validant par des mesures expérimentales. La dernière partie traite de l'optimisation d'un micro-accéléromètre de type VIA (Vibrating Inertial Accelerometer) et l'étude de l'annulation des non linéarités permettant d'améliorer la résolution d'un capteur MEMS vibrant / MEMS (Micro Electro Mechanical Systems) sensors are micro-systems implementing various fields of physics (electronical, mechanical, chemical, optical, ...) and measuring various physical quantities (acceleration, pressure, temperature ...). The vibrating MEMS are characterized by a micro-resonator vibrating at its resonant frequency. The frequency variation is proportional to the measurand. This thesis is concerned with analyzing and identifying the frequency resolution limits of these vibrating sensors by performing multiphysics modeling. The first step is to model the multiphysics behavior of a vibrating MEMS sensor with three transduction types (piezoelectrical, electrostatical and optical). Secondly, the equations developed are validated, based on simulations with Cadence (multiphysique language Verilog-A) and their comparaison with experimental measurements. The last section presents the micro-accelerometer VIA (Vibrating Inertial Accelerometer) optimization and the nonlinearities cancellation study for improving the resolution of vibrating MEMS sensor