4 resultados para Multi-Dimensional Random Walk
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
The objective of this work was to access and understand the teaching social representation (MOSCOVICI, 2005) for the teachers of the children education and fundamental education at Queimadas city, Paraíba. We assume that one representation that allows the teacher to name its profession and to act on it, is a derivative of regularities that are expressed by means of a habitus (BOURDIEU, 1983a), generative matrix of perception and action. This teaching habitus is originated from the experiences and the trajectories of social and professional life of the group. Therefore, from some variables, we tried to access the profile of the group of teachers studied and to get closer of their life style to understand their profession choice and the teaching social representation for this group. In this research, it was used four data sources: a) the questionnaires of characterization; b) the questionnaires of practices and meanings; c) the experience reports and; d) the interviews in depth. The analysis of the data collected was done by means of the simple statistics (frequency), the intersection of variables through cross tables and, the thematic analysis of the contents. The results show that there is a lightly homogeneous group in terms of its social origin and its life style, moreover, they conduct to an overlap between this origin/style and the professional choice. On the other hand, the teacher representation is multi-dimensional such that, all dimensions intercept and articulate with each other to provide a concise teacher representation. They are four dimensions: love and care, help and donation, teaching and learning and, sacrifice and hope. The elements of the teacher representation are substantiated in the schemes of perception and appreciation of the group, in the regularities and life experiences in the context of religion, family, gender and profession. In these regularities we find the elements that comprise the teaching habitus which drives perception and action, representation and daily practice of these teachers. The teaching social representation is still perceived as a threshold for the professional identity of the group of teachers considered. We also observed that there are signs of changes in the practices used by these professionals since they graduate from the course of pedagogy. However, it is not possible to say that these changes are isolated or they lead to a transformation in the teaching habitus or the teaching social representation
Resumo:
The study of aerodynamic loading variations has many engineering applications, including helicopter rotor blades, wind turbines and turbo machinery. This work uses a Vortex Method to make a lagrangian description of the a twodimensional airfoil/ incident wake vortex interaction. The flow is incompressible, newtonian, homogeneus and the Reynolds Number is 5x105 .The airfoil is a NACA 0018 placed a angle of attack of the 0° and 5°simulates with the Painel Method with a constant density vorticity panels and a generation poit is near the painel. The protector layer is created does not permit vortex inside the body. The vortex Lamb convection is realized with the Euler Method (first order) and Adans-Bashforth (second order). The Random Walk Method is used to simulate the diffusion. The circular wake has 366 vortex all over positive or negative vorticity located at different heights with respect to the airfoil chord. The Lift was calculated based in the algorithm created by Ricci (2002). This simulation uses a ready algorithm vatidated with single body does not have a incident wake. The results are compared with a experimental work The comparasion concludes that the experimental results has a good agrement with this papper
Resumo:
Difusive processes are extremely common in Nature. Many complex systems, such as microbial colonies, colloidal aggregates, difusion of fluids, and migration of populations, involve a large number of similar units that form fractal structures. A new model of difusive agregation was proposed recently by Filoche and Sapoval [68]. Based on their work, we develop a model called Difusion with Aggregation and Spontaneous Reorganization . This model consists of a set of particles with excluded volume interactions, which perform random walks on a square lattice. Initially, the lattice is occupied with a density p = N/L2 of particles occupying distinct, randomly chosen positions. One of the particles is selected at random as the active particle. This particle executes a random walk until it visits a site occupied by another particle, j. When this happens, the active particle is rejected back to its previous position (neighboring particle j), and a new active particle is selected at random from the set of N particles. Following an initial transient, the system attains a stationary regime. In this work we study the stationary regime, focusing on scaling properties of the particle distribution, as characterized by the pair correlation function ø(r). The latter is calculated by averaging over a long sequence of configurations generated in the stationary regime, using systems of size 50, 75, 100, 150, . . . , 700. The pair correlation function exhibits distinct behaviors in three diferent density ranges, which we term subcritical, critical, and supercritical. We show that in the subcritical regime, the particle distribution is characterized by a fractal dimension. We also analyze the decay of temporal correlations
Resumo:
The random walk models with temporal correlation (i.e. memory) are of interest in the study of anomalous diffusion phenomena. The random walk and its generalizations are of prominent place in the characterization of various physical, chemical and biological phenomena. The temporal correlation is an essential feature in anomalous diffusion models. These temporal long-range correlation models can be called non-Markovian models, otherwise, the short-range time correlation counterparts are Markovian ones. Within this context, we reviewed the existing models with temporal correlation, i.e. entire memory, the elephant walk model, or partial memory, alzheimer walk model and walk model with a gaussian memory with profile. It is noticed that these models shows superdiffusion with a Hurst exponent H > 1/2. We study in this work a superdiffusive random walk model with exponentially decaying memory. This seems to be a self-contradictory statement, since it is well known that random walks with exponentially decaying temporal correlations can be approximated arbitrarily well by Markov processes and that central limit theorems prohibit superdiffusion for Markovian walks with finite variance of step sizes. The solution to the apparent paradox is that the model is genuinely non-Markovian, due to a time-dependent decay constant associated with the exponential behavior. In the end, we discuss ideas for future investigations.