Link travel time estimation in urban areas by detectors and probe vehicles fusion

International audienceThis paper presents an approach to estimate link travel time in urban areas. This approach consists of a data fusion from underground loop detectors and probe vehicles equipped with global positioning system (GPS). This method is expected to be more accurate, reliable and robust than using either of these data sources alone. In this approach, an algorithm is developed. This algorithm is based on the unscented Kalman filter using vehicle counts and flows from loop detectors located at the end of every link, and travel time from probe vehicles. From these counts the average travel time is calculated using the "cumulative plot" method. Furthermore, in order to incorporate the GPS data, a map-matching method is used to associate a travel time to the appropriate link

Direct powder extrusion 3d printing of praziquantel to overcome neglected disease formulation challenges in paediatric populations

For the last 40 years, praziquantel has been the standard treatment for schistosomiasis, a neglected parasitic disease affecting more than 250 million people worldwide. However, there is no suitable paediatric formulation on the market, leading to off-label use and the splitting of commercial tablets for adults. In this study, we use a recently available technology, direct powder extrusion (DPE) three-dimensional printing (3DP), to prepare paediatric Printlets™ (3D printed tablets) of amorphous solid dispersions of praziquantel with Kollidon® VA 64 and surfactants (Span™ 20 or Kolliphor® SLS). Printlets were successfully printed from both pellets and powders obtained from extrudates by hot melt extrusion (HME). In vitro dissolution studies showed a greater than four-fold increase in praziquantel release, due to the formation of amorphous solid dispersions. In vitro palatability data indicated that the printlets were in the range of praziquantel tolerability, highlighting the taste masking capabilities of this technology without the need for additional taste masking excipients. This work has demonstrated the possibility of 3D printing tablets using pellets or powder forms obtained by HME, avoiding the use of filaments in fused deposition modelling 3DP. Moreover, the main formulation hurdles of praziquantel, such as low drug solubility, inadequate taste, and high and variable dose requirements, can be overcome using this technology

Estimation du temps de parcours d’un réseau urbain par fusion de données de boucles magnétiques et de véhicules traceurs : Une approche stochastique avec mise en oeuvre d’un filtre de Kalman sans parfum

Travel time information is easy to be perceived by users and has the potential to reduce congestion on both temporal and spatial scales thanks to traveller assistance systems. This thesis addresses the problem of estimating the travel time in city, where traffic is characterized by variable flow and also significant perturbation from/to mid-link source/sink that are not equipped with traffic sensors. This flow disturbs the equation of conservation of vehicles. The bibliography contains deterministic and stochastic approaches, using, in specific experimental situations, either inductive loops or probe vehicles, or both. We propose a stochastic approach based on unscented Kalman filtering. Its dynamic model is based on the classical analytical procedure that considers the time difference between the total of incoming and outgoing vehicles for each segment of the network. The formulation of this model is not explicit, which justifies the use of an unscented filter. The observations are both loop counters at the exit sections and probe vehicles map-matched to the network. The algorithm is applicable in real time, without prior information on the percentage of turning movements at intersections, and under any condition of perturbation. The variance estimation output by the filter measures the confidence in the estimated travel time and allows the rejection of outliers. The validation was shown based on simulations on a simple network with three intersections, variable entering flows, variable percentage of perturbation, and a variable percentage of probe vehicles.La notion de temps de parcours est une information simple à intégrer par les usagers des transports et a le potentiel, via des systèmes d’assistance, de réduire la congestion aussi bien de manière temporelle que spatiale. Cette thèse porte sur la problématique de l’estimation du temps de parcours en ville, où la circulation se caractérise par un débit variable et un flux significatif de/vers des voies transversales non équipées de capteurs de trafic, flux qui agit comme perturbation de l’équation de conservation des véhicules. La bibliographie présente des approches déterministes et stochastiques, utilisant, selon les situations expérimentales, soit des boucles inductives, soit des véhicules traceurs, soit les deux. Nous proposons une méthode stochastique du type filtrage de Kalman sans parfum. Son modèle dynamique est basé sur la méthode analytique classique des stocks qui considère le décalage temporel entre les cumuls de véhicules entrants et sortants dans chaque tronçon du réseau. La formulation de ce modèle n’est pas explicite, ce qui justifie l’utilisation d’un filtre sans parfum. Les observations utilisées sont à la fois les boucles magnétiques à la sortie des tronçons et les véhicules traceurs après map-matching sur le réseau. L’algorithme est applicable en temps réel, sans connaissance a priori des affectations aux carrefours, et sous conditions éventuelles de perturbation. En sortie de filtre, on dispose des variances d’estimation, ce qui mesure la confiance dans le temps de parcours estimé et permet de rejeter des mesures aberrantes. La validation a été montrée sur la base de simulations sur un réseau simple à trois intersections, avec des flux variables et des perturbations, et pour quelques pourcents de véhicules traceurs