Parallel synchronous algorithm for nonlinear fixed point problems

We give in this paper a convergence result concerning parallel synchronous algorithm for nonlinear fixed point problems with respect to the euclidian norm in \Rn. We then apply this result to some problems related to convex analysis like minimization of functionals, calculus of saddle point, convex programming..

Autonomous mobile robot with ORB-SLAM 2

In this thesis we introduced ORB-SLAM2. It is critical for a mobile robot to be able to identify revisited locations or loop closures while conducting Simultaneous Localization and Mapping (SLAM) in order to be successful during autonomous navigation. When creating maps, it has been determined that one of the most difficult data association problems is loop closure. It is an effective method of eliminating mistakes and increasing the precision of the robot's localization and mapping capabilities. For the purpose of resolving the loop closure issue, the ORB-SLAM method is used, which is a feature-based simultaneous localization and mapping system that works in real time. This system incorporates loop closure and relocalization, as well as the ability to do automated initialization. The monocular cameras are used to test the algorithm's performance in order to ensure that it is working properly. An important goal of this thesis is to demonstrate the accuracy of the relocalization and loop closure processes while utilizing the ORB SLAM2 algorithm in a range of different environmental conditions. The effectiveness of relocalization and loop closure in a variety of difficult indoor settings is shown via the use of a variety of experiment. According to the results of the studies, the monocular SLAM provides an accurate outcome in the interior environment. The ORB-SLAM 2 findings show the usability of the technique for autonomous navigation and future automated vehicles equipped with a low-coast monocular camera. The ORB-SLAM 2 results also demonstrate the usability of the approach for future driverless vehicles. Keywords: ORB-SLAM2; keyframe; map points localization, relocatio

On Differential Inclusions with Unbounded Right-Hand Side

2000 Mathematics Subject Classification: 58C06, 47H10, 34A60.The classical Filippov's Theorem on existence of a local trajectory of the differential inclusion [\dot x](t) О F(t,x(t)) requires the right-hand side F(·,·) to be Lipschitzian with respect to the Hausdorff distance and then to be bounded-valued. We give an extension of the quoted result under a weaker assumption, used by Ioffe in [J. Convex Anal. 13 (2006), 353-362], allowing unbounded right-hand side

Comparison between DRF for displacement and acceleration spectra with uncertain damping for EC8

The damping force exerted by a structure during an earthquake differs significantly from that specified in the design process. This introduces uncertainties in the design process of structures under earthquake loads. Accordingly, it is desirable to consider not only the effect of randomness of the seismic load but also the uncertainties in the structural parameters. This paper investigates the effect of uncertainties inherent in the damping ratio on the use of damping reduction factor (DRF) for the evaluation of high damping response spectra for linear structures with viscous damping. The DRFs are evaluated from both acceleration and displacement response spectra. Effects of period of vibration, level of damping ratio, soil class and uncertainties level of damping on the DRFs are evaluated and discussed. A numerical analysis implies that the maximum relative error estimated between the deterministic DRF and the DRF considering uncertainties in damping is about 14%. This implies that the damping uncertainty with = 20% leads to an error in DRF of Cv=13 % which is a significant error in estimating the structure response

A JPEG-Like Algorithm for Compression of Single-Sensor Camera Image

International audienceThis paper presents a JPEG-like coder for image compression of single-sensor camera images using a Bayer Color Filter Array (CFA). The originality of the method is a joint scheme of compression.demosaicking in the DCT domain. In this method, the captured CFA raw data is first separated in four distinct components and then converted to YCbCr. A JPEG compression scheme is then applied. At the decoding level, the bitstream is decompressed until reaching the DCT coefficients. These latter are used for the interpolation stage. The obtained results are better than those obtained by the conventional JPEG in terms of CPSNR, DeltaE2000 and SSIM. The obtained JPEG-like scheme is also less complex

Modélisation du renard hydraulique et interprétation de l'essai d'érosion de trou

National audienceL'érosion par renard hydraulique est l'une des causes de rupture des ouvrages hydrauliques. Elle est liée à la formation et au développement d'un tunnel continu entre l'amont et l'aval. L'essai d'érosion au trou est très utilisé pour quantifier la cinétique d'érosion par renard. Toutefois, peu de travaux ont porté sur la modélisation de cette expérimentation. A partir des équations d'écoulement diphasique avec diffusion, et des équations de saut avec érosion, un modèle à deux paramètres décrivant l'agrandissement d'un conduit par érosion hydraulique est proposé. Le premier paramètre est la contrainte seuil. Le second paramètre est le coefficient d'érosion. La comparaison avec des résultats expérimentaux publiés valide le modèle. Nous en déduisons alors, pour un ouvrage hydraulique (barrage , digue), une évaluation du temps restant jusqu'à la brêche

Distribution and mobility of lead and zinc atmospheric depositions in industrial area soil of Tiaret, Algeria

Heavy metal contamination is a severe environmental problem. Knowledge of the total heavy metals contents of soils is a necessary step for making an accurate appraisal and quantitative evaluation of the extent of contamination, indeed, wet and dry atmospheric deposits, plays an important role in the cycle of semi-volatile contaminants [1]. Metallurgical industries release heavy metals into the atmosphere, these last, clump together to form fines particles suspended in the air, these metals can be transported by wind via aerosol or aqueous pathway and deposited in the soil. The main aim of this work was to study the mobility and fate of lead and zinc from atmospheric deposits in contaminated soil from the foundry (ALFET) in industrial zone of Tiaret (Western Algeria) and to determine the effect of physicochemical parameters of the soil on their mobility in the topsoil. Physicochemical analysis of 35 soil samples have shown that zinc and lead levels contents in the surface layer soil (0-30 cm) vary depending on the pH, total limestone (CaCO3) and the soil water content. Results clearly show that soil texture and fine fraction (clay and sand) significantly influence mobility of Pb and Zn in soil

Effects of aggregate size on water retention capacity and microstructure of lime-treated silty soil

International audienceLime treatment is a common technique of improving the workability and geotechnical properties of soils. In this study, the aggregate size effects on the water retention capacity and microstructure of lime-treated soil were investigated. Two soil powders with different maximum aggregate sizes (D max = 0·4 and 5 mm) were prepared and stabilised by 2% lime (by weight of dry soil). Soil samples were prepared by compaction at dry side of optimum water content (w = 17%) with a dry density of 1·65 Mg/m 3. Suction and pore size distribution were determined after different curing periods. The results obtained show that: (a) the treated soil with smaller D max presents relatively smaller modal sizes and lower frequency of macropores (10–330 μm); (b) lime addition effectively improves the soil water retention capacity and decreases both the modal sizes of macro-and micropores gradually over time. Moreover, a higher air entry value and larger water retention capacity were also observed for a smaller D max value, in agreement with the pore size distributions