Recurrent Convolutional Neural Networks for Scene Parsing

Scene parsing is a technique that consist on giving a label to all pixels in an image according to the class they belong to. To ensure a good visual coherence and a high class accuracy, it is essential for a scene parser to capture image long range dependencies. In a feed-forward architecture, this can be simply achieved by considering a sufficiently large input context patch, around each pixel to be labeled. We propose an approach consisting of a recurrent convolutional neural network which allows us to consider a large input context, while limiting the capacity of the model. Contrary to most standard approaches, our method does not rely on any segmentation methods, nor any task-specific features. The system is trained in an end-to-end manner over raw pixels, and models complex spatial dependencies with low inference cost. As the context size increases with the built-in recurrence, the system identifies and corrects its own errors. Our approach yields state-of-the-art performance on both the Stanford Background Dataset and the SIFT Flow Dataset, while remaining very fast at test time

Adiabatic Charge Pumping through Quantum Dots in the Coulomb Blockade Regime

We investigate the influence of the Coulomb interaction on the adiabatic pumping current through quantum dots. Using nonequilibrium Green's functions techniques, we derive a general expression for the current based on the instantaneous Green's function of the dot. We apply this formula to study the dependence of the charge pumped per cycle on the time-dependent pumping potentials. The possibility of charge quantization in the presence of a finite Coulomb repulsion energy is investigated in the light of recent experiments.Comment: 11 pages, 10 figure

Fractal Conductance Fluctuations of Classical Origin

In mesoscopic systems conductance fluctuations are a sensitive probe of electron dynamics and chaotic phenomena. We show that the conductance of a purely classical chaotic system with either fully chaotic or mixed phase space generically exhibits fractal conductance fluctuations unrelated to quantum interference. This might explain the unexpected dependence of the fractal dimension of the conductance curves on the (quantum) phase breaking length observed in experiments on semiconductor quantum dots.Comment: 5 pages, 4 figures, to appear in PR

The role of the disorder range and electronic energy in the graphene nanoribbons perfect transmission

Numerical calculations based on the recursive Green's functions method in the tight-binding approximation are performed to calculate the dimensionless conductance $g$ in disordered graphene nanoribbons with Gaussian scatterers. The influence of the transition from short- to long-ranged disorder on $g$ is studied as well as its effects on the formation of a perfectly conducting channel. We also investigate the dependence of electronic energy on the perfectly conducting channel. We propose and calculate a backscattering estimative in order to establish the connection between the perfectly conducting channel (with $g=1$) and the amount of intervalley scattering.Comment: 7 pages, 9 figures. To be published on Phys. Rev.

Some Remarks about Variable Mass Systems

We comment about the general argument given to obtain the rocket equation as it is exposed in standard textbooks. In our opinion, it can induce students to a wrong answer when solving variable mass problems.Comment: 2 page

Topologically massive gravity as a Pais-Uhlenbeck oscillator

We give a detailed account of the free field spectrum and the Newtonian limit of the linearized "massive" (Pauli-Fierz), "topologically massive" (Einstein-Hilbert-Chern-Simons) gravity in 2+1 dimensions about a Minkowski spacetime. For a certain ratio of the parameters, the linearized free theory is Jordan-diagonalizable and reduces to a degenerate "Pais-Uhlenbeck" oscillator which, despite being a higher derivative theory, is ghost-free.Comment: 9 pages, no figures, RevTEX4; version 2: a new paragraph and a reference added to the Introduction, a new appendix added to review Pais-Uhlenbeck oscillators; accepted for publication in Class. Quant. Gra

Arthur Bispo do Rosário: nas tramas da loucura, teceu sua Arte

Este artigo nos remete às reflexões sobre a linha imaginária que possa haver entre a arte e loucura. Com base em que critérios, podemos afirmar que as psicoses se manifestam em arstas pláscos? Ou até que ponto as obras de um psicótico, tais como Arthur Bispo do Rosário, podem ser consideradas obras de arte. Neste contexto, é oportuno questionar: será que a loucura manifesta a arte ou a arte manifesta a loucura? Arthur Bispo do Rosário viveu a maior parte de sua vida na Colônia Juliano Moreira, do Rio de janeiro. Foi submetida às práticas médicas de tratamento padrão, para a época, praticada em pacientes internados. Não obstante, como um cavaleiro solitário, conforme descreve Luciana Hidalgo, criou seu mundo onírico e obedecia às vozes que escutava dentro de si. A partir daí, ia desfiando os tecidos dos uniformes e recolhendo objetos descartados ou em desuso, metamorfoseando-os em obras, hoje consideradas obras de arte, nacional e internacionalmenteABSTRACT: This article regards to the reflecons on the imaginary line that can exist between art and madness. Based on what criteria can we see that the psychoses are manifested in artists? Or to what extent the work of a psychoc, such as Arthur Bispo do Rosário, can be considered works of art? In this context, it is appropriate to ask: will the madness manifests art or art expresses the madness? Arthur Bispo do Rosário lived most of his life in the Juliano Moreira Colony of Rio de Janeiro. He was submied to current medical treatment for the time, practiced in hospitalized patients. Nevertheless, as a lonely rider, as described by Luciana Hidalgo, created his dream world and obeyed the voices inside his head. Thereatier, he unraveled the tissue of uniforms and collected discarded or unused objects, morphing them into pieces now considered works of art, nationally and internationallyinfo:eu-repo/semantics/publishedVersio

Design and Validation of a High-Level Controller for Automotive Active Systems

Active systems, from active safety to energy management, play a crucial role in the development of new road vehicles. However, the increasing number of controllers creates an important issue regarding complexity and system integration. This article proposes a high-level controller managing the individual active systems - namely, Torque Vectoring (TV), Active Aerodynamics, Active Suspension, and Active Safety (Anti-lock Braking System [ABS], Traction Control, and Electronic Stability Program [ESP]) - through a dynamic state variation. The high-level controller is implemented and validated in a simulation environment, with a series of tests, and evaluate the performance of the original design and the proposed high-level control. Then, a comparison of the Virtual Driver (VD) response and the Driver-in-the-Loop (DiL) behavior is performed to assess the limits between virtual simulation and real-driver response in a lap time condition. The main advantages of the proposed design methodology are its simplicity and overall cooperation of different active systems, where the proposed model was able to improve the vehicle behavior both in terms of safety and performance, giving more confidence to the driver when cornering and under braking. Some differences were discovered between the behavior of the VD and the DiL, especially regarding the sensitivity to external disturbances

On the applicability of Backus' mantle filter theory

Geomagnetic jerks are sudden changes of trend in the geomagnetic secular variation. The Earth's mantle behaves as a filter for the jerks, causing a delayed and a smoothed signal at the Earth's surface. Backus' mantle filter theory relies on approximating the impulse response function (IRF) of the mantle by a Gaussian. The advantage of this theory is the linear relation between jerks' delay times and the mantle electrical conductivity, as expressed by kernels. However, the limitations of this theory arise when negative delay and/or smoothing times occur. The applicability of the mantle filter theory is examined by analysing the validity of the Gaussian as an approximation for the composite IRF (CIRF) at a given location. We show that the electrical conductivity of the lower mantle is mostly responsible for the jerk delay time. Alternating sign CIRFs might cause negative delay and/or smoothing times which prevents the use of the mantle filter theory. Adequate/inadequate Gaussian approximations to the CIRFs give small/large differences in the convolved jerk occurrence times. Most observatories yield positive time constants, but in most cases the difference in the jerk occurrence times exceeds 0.5y