Real-time Collision Risk Estimation based on Stochastic Reachability Spaces

International audienceEstimating the risk of collision with other road users is one of the most important modules to ensure safety in autonomous driving scenarios. In this paper, we propose new probabilistic models to obtain Stochastic Reachability Spaces for vehicles and pedestrians detected in the scene. We then exploit these probabilistic predictions of the road-users' future positions, along with the expected ego-vehicle trajectory, to estimate the probability of collision risk in real-time. The proposed stochastic models only depend on the velocity, acceleration, tracked bounding box, and the class of the detected object. This information can easily be obtained through off-the-shelf 3D object detection frameworks. As a result, the proposed approach for collision risk estimation is widely applicable to a variety of autonomous vehicle platforms. To validate our approach, initially we test the stochastic motion prediction on the KITTI dataset. Further experiments in the CARLA simulator, by reproducing realistic collision scenarios, have the goal of demonstrating the effectiveness of the collision risk assessment and are compared with an alternative approach

Parametric studies of methyl esters synthesis from Thumba seed oil using heterogeneous catalyst under conventional stirring and ultrasonic cavitation

The depletion of petroleum resources has created great demand for environmental friendly renewable energy sources. Biodiesel is one of the alternatives to petroleum fuels. The objective of present study is to produce biodiesel (Thumba methyl ester) from Thumba oil in presence acidic ion exchange resin i.e. Amberlyst 15 catalyst followed by results of experimental investigation carried out by the conventional stirring method as well as an ultrasonic cavitation method. The effect of molar ratio (1:4 to 1:8 (oil to alcohol)), catalyst concentration (1.0–1.4% (Weight of catalyst/Weight of oil)), Reaction temperature (55 °C–70 °C) on yield of fatty acid methyl ester (FAME) and conversion of triglycerides (TG) were studied by keeping other process parameter constant. Many experiments were employed to investigate the effects of these parameters. Using conventional stirring method, More than 91% conversion of TG was obtained at optimum values of 65 °C in 1 h with 1:6 oil to methanol molar ratio and catalyst concentration of 1.2% Amberlyst 15 in oil. A higher yield of thumba methyl ester about 89% and conversion of triglycerides about 97% was obtained in ultrasonic cavitation reactor within 40 min only. The optimized values of temperature, oil to alcohol molar ratio and catalyst concentration were found to be 65 °C, 1:6 molar ratio and 1.2 wt% of oil respectively. Ultrasonic cavitation method was found to be more rapid, energy efficient and time saving over conventional stirring method. Thermodynamic parameters such as standard heat of reaction, standard Gibbs free energy change and equilibrium constant at optimized operating conditions were reported. A kinetic study of transesterification of Thumba oil for conventional heating method is presented in this paper. The observed rate constant for the overall reaction was of two orders. The experimental data thus obtained was well fitted to the second order kinetics with respect to methanol. Keywords: Biodiesel, Citrullus colocyntis, Thumba oil, Transesterification, Fatty acid methyl ester (FAME

Pushout Bond Strength of Root Fillings after Irrigation of Root Canals Utilizing Sodium Hypochlorite, Chlorhexidine, and Homeopathic Mother Tincture (<i>Arnica Montana</i>)

The pushout bond strength of root fillings at radicular dentin was investigated employing NaOCl, CHX, and homoeopathic mother tincture (Arnica montana) as an irrigant. Sixty human permanent single-rooted extracted teeth were decoronated. The root canals were instrumented using Pro taper universal rotary system (Dentsply Tulsa Dental; Tulsa, Oklahoma) and were prepared up to F3 apical size. The roots were then randomly divided into three groups according to irrigation solution (n = 20) according to the final irrigation regimen: Group I: 3 mL 5.25% NaOCl followed by 3 mL Saline (control); Group II: 3 mL Arnica montana (10%, w/v) followed by 3 mL Saline; Group III: 3 mL CHX followed by 3 mL Saline. The canals were dried using paper points. The canals were coated with AH Plus sealer (Dentsply DeTey, Konstaz, Germany) with the aid of a Lentulo spiral (Dentsply DeTey, Konstaz, Germany) and obturated with #F3 gutta-percha. Each root was then horizontally sliced into three slices, labelled coronal, middle, and apical, each measuring 2 mm thick. Furthermore, at a crosshead speed of 2 mm/min, the test was carried out using the universal testing apparatus. The 5.25% NaOCl significantly decreased the bond strength of AH Plus to dentin. Both CHX and Arnica montana were capable of reversing the compromised pushout of AH Plus to NaOCl-treated dentin. After using NaOCl as an irrigant, the danger of diminished binding capacity of AH Plus to root canal walls arises. Final irrigation with Arnica montana and CHX reduces this risk