Pedestrian Detection in Crowded Environments through Bayesian Prediction of Sequential Probability Matrices

In order to safely navigate populated environments, an autonomous vehicle must be able to detect human shapes using its sensory systems, so that it can properly avoid a collision. In this paper, we introduce a Bayesian approach to the Viola-Jones algorithm, as a method to automatically detect pedestrians in image sequences. We present a probabilistic interpretation of the basic execution of the original tool and develop a technique to produce approximate convolutions of probability matrices with multiple local maxima

Ab initio study of the influence of nanoscale doping inhomogeneities in the phase separated state of La1−x_{1-x}Cax_{x}MnO3_3

The chemical influence in the phase separation phenomenon that occurs in perovskite manganites is discussed by means of ab initio calculations. Supercells have been used to simulate a phase separated state, that occurs at Ca concentrations close to the localized to itinerant crossover. We have first considered a model with two types of magnetic ordering coexisting within the same compound. This is not stable. However, a non-isotropic distribution of chemical dopants is found to be the ground state. This leads to regions in the system with different effective concentrations, that would always accompany the magnetic phase separation at the same nanometric scale, with hole-rich regions being more ferromagnetic in character and hole-poor regions being in the antiferromagnetic region of the phase diagram, as long as the system is close to a phase crossover.Comment: 8 pages, 7 figures, 1 tabl

Thermoelectric simulation of electric machines with permanent magnets

The objective of this work is to describe some numerical tools developed to perform the thermoelectric simulation of electric machines. From the electromagnetic point of view, we will focus on the computation of nonlinear 2D transient magnetic fields where the data concerning the electric current sources involve potential drops excitations. From the thermal point of view, once the electromagnetic losses are known, we will show an application of a Galerkin lumped parameter method (GLPM) to simulate the thermal behavior of an electric motor. The proposed methods are applied to the simulation of a permanent magnet synchronous electric motor

Pressure-induced metal-insulator transition in MgV_2O_4

On the basis of experimental thermoelectric power results and ab initio calculations, we propose that a metal-insulator transition takes place at high pressure (approximately 6 GPa) in MgV_2O_4.Comment: 2 pages, 3 figures, accepted in Physica B (Strongly Correlated Electron Systems '07

Enhanced dimerization of TiOCl under pressure: spin-Peierls - to - Peierls transition

We report high-pressure x-ray diffraction and magnetization measurements combined with ab-initio calculations to demonstrate that the high-pressure optical and transport transitions recently reported in TiOCl, correspond in fact to an enhanced Ti3+-Ti3+ dimerization existing already at room temperature. Our results confirm the formation of a metal-metal bond between Ti3+ ions along the b-axis of TiOCl, accompanied by a strong reduction of the electronic gap. The evolution of the dimerization with pressure suggests a crossover from the spin-Peierls to a conventional Peierls situation at high pressures.Comment: 9pages, 4 figure

Fermiology and transport properties of the half-metallic itinerant ferromagnet CoS2_2: influence of spin orbit coupling

Electronic structure calculations were performed on the compound CoS$_2$, an itinerant ferromagnet whose magnetic properties can be understood in terms of spin fluctuation theory. We have identified nesting features in the Fermi surface of the compound, active for long wavelength spin fluctuations. The electronic structure of the material is close to a half-metal. We show the importance of introducing spin-orbit coupling (SOC) in the calculations, that partially destroys the half-metallicity of the material. By means of transport properties calculations, we have quantified the influence of SOC in the conductivity at room temperature, with an important decrease comparing to the GGA alone conductivity. SOC also helps to understand the negative 0 of the material, whose conductivity varies by a few percent with the introduction of small perturbations in the states around the Fermi level.Comment: 8 pages, 8 figure

Was Mesosaurus an aquatic animal? How do we know If an ancient species was aquatic or terrestrial?

Mesosaurs are lizard-like reptiles that lived at the beginning of the Permian Period (280–290 million years ago) or even earlier. Mesosaurs are known from thousands of skeletons recovered in Uruguay, Brazil, and Southern Africa, including young and adult individuals and even an embryo and a pregnant female. For years, mesosaurs have been considered aquatic (water-living) animals, because they have several characteristics of species that are adapted to an aquatic life, like webbed hands and feet and the presence of thickened and compact bones. However, mesosaurs also share several features with terrestrial (land-living) species, such as the structure of the hips, the limbs, and the heels. To figure out whether mesosaurs are actually aquatic or terrestrial, we studied vertebral columns (backbones) of Mesosaurus and compared them to those of other aquatic and terrestrial animals. Studying the variations in the length of the vertebrae can reveal how the animals moved and whether they were adapted to terrestrial or aquatic environments. Surprisingly, we found that Mesosaurus is more similar to terrestrial animals, which changes our ideas about their lifestyle

The Historical Significance of the Welded Tuffs from Arucas, Canary Islands

[Abstract] Arucas Stone (Piedra de Arucas) is a welded tuff quarried in the town of Arucas, on the island of Gran Canaria in the Canary Archipelago. This rock has been quarried for centuries, not only for building but also for many other purposes, such as manufacturing water cisterns or conduits, and especially for carving. The quarrying and economic activity related to this stone have profoundly shaped the history and economy of the city of Arucas, in terms not only of extraction, but also of a highly valued local artisan tradition of stone carving. Immigrants from the Canary Islands even brought this stone to several countries in South America, where it was used to erect numerous important architectural heritage sites. Nowadays, this stone is only quarried in two areas, even though it is often required for the restoration and rehabilitation of historical buildings. Its special characteristics, and, above all, its historical importance, make this stone a prime candidate for Global Heritage Stone designation

Biomechanical analysis of the penalty-corner drag-flick of elite male and female hockey players

The aim of this study was to analyse the kinematic sequencing in the penalty-corner drag-flicks of elite male and female field hockey players of international calibre. Thirteen participants (one skilled male drag-flicker and six male and six female elite players) participated in the study. An optoelectronic motion analysis system was used to capture the drag-flicks with six cameras, sampling at 250 Hz. Select ground reaction force parameters were obtained from a force platform which registered the last support of the front foot. Twenty trials were captured from each subject. Both player groups showed significantly (p < 0.05) smaller ball velocity at release, peak angular velocity of the pelvis, and negative and positive peak angular velocities of the stick than the skilled subject. Normalised ground reaction forces of the gender groups were also smaller than that of the skilled drag-flicker. By comparing these players we established that the cues of the skill level are a wide stance, a whipping action (rapid back lift) of the stick followed by an explosive sequential movement of the pelvis, upper trunk and stick