Universality class for bootstrap percolation with m=3m=3 on the cubic lattice

We study the $m=3$ bootstrap percolation model on a cubic lattice, using Monte Carlo simulation and finite-size scaling techniques. In bootstrap percolation, sites on a lattice are considered occupied (present) or vacant (absent) with probability $p$ or $1-p$, respectively. Occupied sites with less than $m$ occupied first-neighbours are then rendered unoccupied; this culling process is repeated until a stable configuration is reached. We evaluate the percolation critical probability, $p_c$, and both scaling powers, $y_p$ and $y_h$, and, contrarily to previous calculations, our results indicate that the model belongs to the same universality class as usual percolation (i.e., $m=0$). The critical spanning probability, $R(p_c)$, is also numerically studied, for systems with linear sizes ranging from L=32 up to L=480: the value we found, $R(p_c)=0.270 \pm 0.005$, is the same as for usual percolation with free boundary conditions.Comment: 11 pages; 4 figures; to appear in Int. J. Mod. Phys.

Inequalities for eigenvalues of operators in divergence form on Riemannian manifolds isometrically immersed in Euclidean space

In this paper, we compute universal inequalities of eigenvalues of a large class of second-order elliptic differential operators in divergence form, that includes, e.g., the Laplace and Cheng-Yau operators, on a bounded domain in a complete Riemannian manifolds isometrically immersed in Euclidean space. A key step in order to obtain the sequence of our estimates is to get the right Yang-type first inequality. We also prove some inequalities for manifolds supporting some special functions and tensors.Comment: 15 pages. arXiv admin note: text overlap with arXiv:2206.0943

Reducing the False Positive Rate Using Bayesian Inference in Autonomous Driving Perception

Object recognition is a crucial step in perception systems for autonomous and intelligent vehicles, as evidenced by the numerous research works in the topic. In this paper, object recognition is explored by using multisensory and multimodality approaches, with the intention of reducing the false positive rate (FPR). The reduction of the FPR becomes increasingly important in perception systems since the misclassification of an object can potentially cause accidents. In particular, this work presents a strategy through Bayesian inference to reduce the FPR considering the likelihood function as a cumulative distribution function from Gaussian kernel density estimations, and the prior probabilities as cumulative functions of normalized histograms. The validation of the proposed methodology is performed on the KITTI dataset using deep networks (DenseNet, NasNet, and EfficientNet), and recent 3D point cloud networks (PointNet, and PintNet++), by considering three object-categories (cars, cyclists, pedestrians) and the RGB and LiDAR sensor modalities.Comment: This paper has been submitted to the journal Pattern Recognition Letter

Quantum mechanics of particles constrained to spiral curves with application to polyene chains

Context: Due to advances in synthesizing lower-dimensional materials, there is the challenge of finding the wave equation that effectively describes quantum particles moving on 1D and 2D domains. Jensen and Koppe and Da Costa independently introduced a confining potential formalism showing that the effective constrained dynamics is subjected to a scalar geometry-induced potential; for the confinement to a curve, the potential depends on the curve’s curvature function.Method: To characterize the π electrons in polyenes, we follow two approaches. First, we utilize a weakened Coulomb potential associated with a spiral curve. The solution to the Schrödinger equation with Dirichlet boundary conditions yields Bessel functions, and the spectrum is obtained analytically. We employ the particle-in-a-box model in the second approach, incorporating effective mass corrections. The π-π* transitions of polyenes were calculated in good experimental agreement with both approaches, although with different wave functions

A Survey on Long-Range Wide-Area Network Technology Optimizations

Long-Range Wide-Area Network (LoRaWAN) enables flexible long-range service communications with low power consumption which is suitable for many IoT applications. The densification of LoRaWAN, which is needed to meet a wide range of IoT networking requirements, poses further challenges. For instance, the deployment of gateways and IoT devices are widely deployed in urban areas, which leads to interference caused by concurrent transmissions on the same channel. In this context, it is crucial to understand aspects such as the coexistence of IoT devices and applications, resource allocation, Media Access Control (MAC) layer, network planning, and mobility support, that directly affect LoRaWAN’s performance.We present a systematic review of state-of-the-art works for LoRaWAN optimization solutions for IoT networking operations. We focus on five aspects that directly affect the performance of LoRaWAN. These specific aspects are directly associated with the challenges of densification of LoRaWAN. Based on the literature analysis, we present a taxonomy covering five aspects related to LoRaWAN optimizations for efficient IoT networks. Finally, we identify key research challenges and open issues in LoRaWAN optimizations for IoT networking operations that must be further studied in the future

On thermalization of magnetic nano-arrays at fabrication

We propose a model to predict and control the statistical ensemble of magnetic degrees of freedom in Artificial Spin Ice (ASI) during thermalized adiabatic growth. We predict that as-grown arrays are controlled by the temperature at fabrication and by their lattice constant, and that they can be described by an effective temperature. If the geometry is conducive to a phase transition, then the lowest temperature phase is accessed in arrays of lattice constant smaller than a critical value, which depends on the temperature at deposition. Alternatively, for arrays of equal lattice constant, there is a temperature threshold at deposition and the lowest temperature phase is accessed for fabrication temperatures {\it larger rather than smaller} than this temperature threshold. Finally we show how to define and control the effective temperature of the as-grown array and how to measure critical exponents directly. We discuss the role of kinetics at the critical point, and applications to experiments, in particular to as-grown thermalized square ASI, and to magnetic monopole crystallization in as-grown honeycomb ASI.Comment: 14 pages, 2 figures. A theoretical approach to experimental results reported in: Morgan J P, Stein A, Langridge S and Marrows C (2010) Nature Physics 7 7

“PREPARE-SE DESDE JÁ”: OS IMPRESSOS DE CUNHO CIVILIZATÓRIO E AS PRESCRIÇÕES PARA O COMPORTAMENTO FEMININO (ANOS 1950)

É na esteira das pesquisas que se ocupam em compreender a sociabilidade, a civilidade e as formas de agir no ambiente privado que pesquisamos uma coleção de impressos de cunho civilizatório, denominado “Pensando em Casar”. O objetivo foi atentar para as imagens relacionadas à família, no sentido de compreender as representações sobre a condição feminina nesse contexto. Foram analisadas 22 revistas publicadas originalmente da França (1954) e traduzidas quase que simultaneamente no Brasil (1955). Na análise dos documentos, destacamos duas categorias: “Representações de casamento e família” e “Comportamento feminino: entre a espera e a conquista”. Nesse conjunto, as representações sobre o comportamento feminino evidenciam que as mulheres a quem se destinava a revista eram favorecidas economicamente. As imagens indicam que as leitoras deveriam estar sempre preparadas para conquistar um marido, formar uma família e permanecer no matrimônio