Comparing and Combining Time Series Trajectories Using Dynamic Time Warping

This research proposes the application of dynamic time warping (DTW) algorithm to analyse multivariate data from virtual reality training simulators, to assess the skill level of trainees. We present results of DTW algorithm applied to trajectory data from a virtual reality haptic training simulator for epidural needle insertion. The proposed application of DTW algorithm serves two purposes, to enable (i) two trajectories to be compared as a similarity measure and also enables (ii) two or more trajectories to be combined together to produce a typical or representative average trajectory using a novel hierarchical DTW process. Our experiments included 100 expert and 100 novice simulator recordings. The data consists of multivariate time series data-streams including multi-dimensional trajectories combined with force and pressure measurements. Our results show that our proposed application of DTW provides a useful time-independent method for (i) comparing two trajectories by providing a similarity measure and (ii) combining two or more trajectories into one, showing higher performance compared to conventional methods such as linear mean. These results demonstrate that DTW can be useful within virtual reality training simulators to provide a component in an automated scoring and assessment feedback system

Comparing and Combining Time Series Trajectories Using Dynamic Time Warping

This is the final version. Available on open access from Elsevier via the DOI in this record20th International Conference on Knowledge Based and Intelligent Information and Engineering Systems, KES2016, 5-7 September 2016, York, UKThis research proposes the application of dynamic time warping (DTW) algorithm to analyse multivariate data from virtual reality training simulators, to assess the skill level of trainees. We present results of DTW algorithm applied to trajectory data from a virtual reality haptic training simulator for epidural needle insertion. The proposed application of DTW algorithm serves two purposes, to enable (i) two trajectories to be compared as a similarity measure and also enables (ii) two or more trajectories to be combined together to produce a typical or representative average trajectory using a novel hierarchical DTW process. Our experiments included 100 expert and 100 novice simulator recordings. The data consists of multivariate time series data-streams including multi-dimensional trajectories combined with force and pressure measurements. Our results show that our proposed application of DTW provides a useful time-independent method for (i) comparing two trajectories by providing a similarity measure and (ii) combining two or more trajectories into one, showing higher performance compared to conventional methods such as linear mean. These results demonstrate that DTW can be useful within virtual reality training simulators to provide a component in an automated scoring and assessment feedback system

Urban Activity Patterns Mining in Wi-Fi Access Point Logs

RÉSUMÉ Aujourd’hui la grande majorité des données sont basée sur des enquêtes ou des études appliquées à des échantillons définis de la population. De plus les méthodes traditionnelles de collecte de données en termes de coûts ainsi que de temps tout en ne garantissant pas la représentativité des observations du fait du biais d’échantillonages et de la relative fiabilité des répondants. La disponibilité grandissantes de bases de données collectées passivements couplé à la forte pénétration des smartphones ont ouvert des perspectives intéressantes concernant la collecte et le traitement automatisé de données de mobilité.----------ABSTRACT This thesis proposes a methodology to mine valuable nformation about the usage of a facility (e.g. building), based only on Wi-Fi network connection history. Data are collected at Concordia University in Montreal, Canada, during one week in Febuary 2015. Using the Wi-Fi access log data, we characterize activities taking place within a building without any additional knowledge of the building itself. Such information can be used to monitor the use of a facility automatically, to study human mobility or as an input information for mobility models