Omnidirectional Vision-Based Control from Homography

International audienc

Synthesis and CO2 sorption of silica particles, kinetics and thermodynamics

Spherical ordered mesoporous silica particles with radially oriented mesopores were successfully prepared by using non-ionic amphiphilic di-block co-polymers CnH2n+1-(EO)x-OH as template and tetraorthosilicate (TEOS) as silica precursor. The synthesized mesoporous silica materials were characterized by XRD, N2 adsorption-desorption and SEM techniques. CO2 adsorption at 0 °C was evaluated by a volumetric method, and the CO2 sorption behavior was described by applying both Langmuir and Freundlich equations. Results indicate a high adsorption capacity of CO2 (5-9 mmol/g), depending essentially on the porous texture of the materials. An adsorption kinetic model was proposed to describe the adsorption of CO2 over template-free mesoporous siliceous materials. A good agreement with experimental data was found

African Dimension in Algerian Contemporaneous Novel: The Case of ‘ZiwanKingdom’, ‘Camarade’ and ‘Manna’ novels of Essedik Hadj Ahmed

Abstract : The purpose of this study is to gain insight into the African dimension in Algerian contemporary novels. The chosen corpus consists of three novels by Algerian novelist Essedik Hadj Ahmed who had a positive attitude toward Africa, aspects of African cultural patrimony abound in his works. He carried out his works in order to clarify Saharan man's issues, pains, desires, and relationships with others. The study took a historical approach to track the emergence and evolution of Algerian novel. The semantic approach was sometimes required to reveal hidden signs and their meanings in the narrative in order to define African dimensions related to space, history, society, economy, and culture. Analysis and description were additionally employed to reveal the presence and effectiveness of African dimensions in shaping and influencing the narrative work. The study concluded that the Algerian contemporaneous novel assumed the role to be the voice of African resistance. Keywords: African dimension, Algerian novel, Sahara, African patrimony, African identity

Effect of limestone fines on the mechanical properties and durability of mortar made with crushed sand

This study investigate the influence of limestone fines (LF) on the mechanical properties, hydration heat and durability (acid and sulfate environments) of mortars made with crushed sand (CS) and different rate replacement of limestone fines of the CS (0%, 5%, 10%, 15%) using three types of cement, that is, ordinary Portland cement, limestone cement and pozzolanic cement. The obtained results show that the limestone fines increase the compressive strength and generate more hydration heat for all the used cements. Mortars made with blended cements, limestone or pozzolan, with 5% and 10% limestone fines, have low expansion when imerged in 5% Na2SO4 solution. In addition, when immerged in acids environment, the mortars with limestone fines exhibit negative effect at long-term durability. However, the mortar manufactured with ordinary Portland cement containing 15% of limestone fines will be strongly affected. It was found that no benefit can be gained from eliminating limestone fines fraction from the CS

Effect of limestone fines on the mechanical properties and durability of mortar made with crushed sand

This study investigate the influence of limestone fines (LF) on the mechanical properties, hydration heat and durability (acid and sulfate environments) of mortars made with crushed sand (CS) and different rate replacement of limestone fines of the CS (0%, 5%, 10%, 15%) using three types of cement, that is, ordinary Portland cement, limestone cement and pozzolanic cement. The obtained results show that the limestone fines increase the compressive strength and generate more hydration heat for all the used cements. Mortars made with blended cements, limestone or pozzolan, with 5% and 10% limestone fines, have low expansion when imerged in 5% Na2SO4 solution. In addition, when immerged in acids environment, the mortars with limestone fines exhibit negative effect at long-term durability. However, the mortar manufactured with ordinary Portland cement containing 15% of limestone fines will be strongly affected. It was found that no benefit can be gained from eliminating limestone fines fraction from the CS

Image-Based Lateral Position, Steering Behavior Estimation, and Road Curvature Prediction for Motorcycles

International audienceThis letter presents an image-based approach to simultaneously estimate the lateral position of a powered-two-wheeled vehicle on the road, its steering behavior and predict the road curvature ahead of the motorcycle. This letter is based on the inverse perspective mapping technique combined with a road lanes detection algorithm capable of detecting straight and curved lanes. Then, a clothoid model is used to extract pertinent information from the detected road markers. Finally, the performance of the proposed approach is illustrated through simulations carried out with the well-known motorcycle simulator “BikeSim.” The results are very promising since the algorithm is capable of estimating, in real time, the road geometry and the vehicle location with a better accuracy than the one given by the commercial GPS

Inverse Perspective Mapping Roll Angle Estimation for Motorcycles

International audienceThis paper presents an image-based approach to estimate the motorcycle roll angle. The algorithm estimates directly the absolute roll to the road plane by means of a basic monocular camera. This means that the estimated roll angle is not affected by the road bank which is often a problem for vehicle observation and control purposes. For each captured image, the algorithm uses a numeric roll loop based on some simple knowledge of the road geometry. For each iteration, a bird-eye-view of the road is generated with the inverse perspective mapping technique. Then, a road marker filter associated with the well-known clothoid model are used respectively to track the road separation lanes and approximate them with mathematical functions. Finally, the algorithm computes two distinct areas between the two-road separation lanes. Its performances are tested by means of the motorcycle simulator BikeSim. This approach is very promising since it does not require any vehicle or tire model and is free of restrictive assumptions on the dynamics

Powered Two-Wheeled Vehicles Steering Behavior Study: Vision-Based Approach

International audienceThis paper presents a vision-based approach to prevent dangerous steering situations when riding a motorcycle in turn. In other words, the proposed algorithm is capable of detecting under, neutral or over-steering behavior using only a conventional camera and an inertial measurement unit. The inverse perspective mapping technique is used to reconstruct a bird-eye-view of the road image. Then, filters are applied to keep only the road markers which are, afterwards, approximated with the well-known clothoid model. That allows to predict the road geometry such that the curvature ahead of the motorcycle. Finally, from the predicted road curvature, the measures of the Euler angles and the vehicle speed, the proposed algorithm is able to characterize the steering behavior. To that end, we propose to estimate the steering ratio and we introduce new pertinent indicators such that the vehicle relative position dynamics to the road. The method is validated on the advanced simulator BikeSim during a steady turn