Towards Human Motion Tracking Enhanced by Semi-Continuous Ultrasonic Time-of-Flight Measurements

Human motion analysis is a valuable tool for assessing disease progression in persons with conditions such as multiple sclerosis or Parkinson’s disease. Human motion tracking is also used extensively for sporting technique and performance analysis as well as for work life ergonomics evaluations. Wearable inertial sensors (e.g., accelerometers, gyroscopes and/or magnetometers) are frequently employed because they are easy to mount and can be used in real life, out-of-the-lab settings, as opposed to video-based lab setups. These distributed sensors cannot, however, measure relative distances between sensors, and are also cumbersome when it comes to calibration and drift compensation. In this study, we tested an ultrasonic time-of-flight sensor for measuring relative limb-to-limb distance, and we developed a combined inertial sensor and ultrasonic time-of-flight wearable measurement system. The aim was to investigate if ultrasonic time-of-flight sensors can supplement inertial sensor-based motion tracking by providing relative distances between inertial sensor modules. We found that the ultrasonic time-of-flight measurements reflected expected walking motion patterns. The stride length estimates derived from ultrasonic time-of-flight measurements corresponded well with estimates from validated inertial sensors, indicating that the inclusion of ultrasonic time-of flight measurements could be a feasible approach for improving inertial sensor-only systems. Our prototype was able to measure both inertial and time-of-flight measurements simultaneously and continuously, but more work is necessary to merge the complementary approaches to provide more accurate and more detailed human motion tracking.publishedVersio

Wireless Instrumentation for Safety Critical Systems. Technology, Standards, Solutions and Future Trends

Wireless communication is an important part of everyday life, but has until recently been considered too unreliable for use in industrial processes. In particular, there has been reluctance to accept wireless systems as part of safety critical operations. This report considers the pros and cons of wireless communication in Safety Instrumented Systems. The report provides an introduction to wireless sensor networks (WSNs), the underlying technology for wireless instrumentation, presenting the history and basic technology enabling the recent development of low-power sensors and actuators. An overview of the different international standards for WSNs is provided, with special focus on the two specifications specifically targeting the process industries; namely WirelessHART and ISA100.11a. Furthermore, current status of wireless instrumentation within the oil and gas industry is summarized, including the financial and operational drivers for going wireless, along with the technical requirements which must be fulfilled for a successful adoption of this new technology. Example reliability calculation of wireless detector system is presented, and the wireless gas detector GasSecure is presented as a case. Finally, future trends and the consequences of using wireless instrumentation in safety critical systems are presented discussed

Laststyring i primærreserven. Utvikling av et SOHz programmerbart frekvensrele

Denne rapporten beskriver resultatene som er oppnådd i SUP prosjektet. Tekniske utførelse har vært gjort av SINTEF Digital, mens Enfo har bidratt med systemdesign, integrasjon og test. Prosjektet har levert et ferdig utviklet frekvensrele som er testet og CE-godkjent av Nemko. Det er klart for kommersiell drift når markedsforholdene ligger til rette for det. Oppdragsgiver: Enfo ASpublishedVersio

Reconstruction non linéaire des processus gaussiens soumis à un jitter aléatoire

L'échantillonnage périodique des processus aléatoires est parfois perturbé par des imperfections du mécanisme de l'échantillonnage. Cet article considère le problème de la reconstruction de tels processus. Nous définissons une méthode non linéaire de reconstruction lorsque le processus de départ est gaussien. La méthode est basée sur l'application de l'algorithme de Viterbi. Nous montrons que, sous certaines conditions que nous spécifierons, elle possède des performances supérieures à la méthode linéaire optimale

Codage par échantillonnage Gaussien

Le jitter aléatoire est normalement perçu comme une interférence perturbante. Dans cet article, nous proposons l'introduction d'un échantillonnage gaussien afin de brouiller des processus stationnaires. Nous montrons, en particulier, que sous certaines conditions que nous spécifierons, le processus de départ peut être reconstruit avec une erreur faible

Utilisation de filtres linéaires périodiques lors d'un accès multi-utilisateurs en MF-TDMA

Le travail présenté dans cet article propose une solution innovante pour faire évoluer de façon simple un système conçu pour de l'accès en MF-TDMA vers un accès semblable à du CDMA. Il est proposé de ne pas modifier les chaînes d'émission et de réception, mais de leur rajouter de l'étalement spectral en utilisant des filtres linéaires périodiques, implémentés par le biais de changements d'horloge périodiques. Cette méthode ressemble à du CDMA dans la mesure où l'information transmise par plusieurs utilisateurs se chevauche en fréquence et en temps et que la reconstruction se fait par la signature particulière de chaque utilisateur qui correspond dans ce cas particulier au filtre associé à chaque utilisateur

Comparison of wireless techniques applied to environmental sensor monitoring

This report investigates the technological basis for low power, low bitrate, medium range, wireless transmission of environmental sensor data. This is a typical 'Internet of Things' (IoT) application, and most of our findings are therefore generally applicable to the wider IoT field. The report starts with an overview of the relevant regulatory framework, in particular the differences between Europe and the USA. It then discusses the various key performance indicators of the wireless IoT communication channel and presents an overview of some of the wireless standards available today. While performances are often discussed, ecosystems appear as important for the sustainability of different systems. Future work includes a more in-depth analysis of selected standards in order to assess the scalability potential. Oppdragsgiver: Norges Forskningsrå