5 resultados para Scale-free network

em Universidade Federal do Rio Grande do Norte(UFRN)


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In this work we study a connection between a non-Gaussian statistics, the Kaniadakis statistics, and Complex Networks. We show that the degree distribution P(k)of a scale free-network, can be calculated using a maximization of information entropy in the context of non-gaussian statistics. As an example, a numerical analysis based on the preferential attachment growth model is discussed, as well as a numerical behavior of the Kaniadakis and Tsallis degree distribution is compared. We also analyze the diffusive epidemic process (DEP) on a regular lattice one-dimensional. The model is composed of A (healthy) and B (sick) species that independently diffusive on lattice with diffusion rates DA and DB for which the probabilistic dynamical rule A + B → 2B and B → A. This model belongs to the category of non-equilibrium systems with an absorbing state and a phase transition between active an inactive states. We investigate the critical behavior of the DEP using an auto-adaptive algorithm to find critical points: the method of automatic searching for critical points (MASCP). We compare our results with the literature and we find that the MASCP successfully finds the critical exponents 1/ѵ and 1/zѵ in all the cases DA =DB, DA DB. The simulations show that the DEP has the same critical exponents as are expected from field-theoretical arguments. Moreover, we find that, contrary to a renormalization group prediction, the system does not show a discontinuous phase transition in the regime o DA >DB.

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In this work we analyse the implications of using a power law distribution of vertice's quality in the growth dynamics of a network studied by Bianconi anel Barabási. In particular, we start studying the random networks which characterize or are related to some real situations, for instance the tide movement. In this context of complex networks, we investigate several real networks, as well as we define some important concepts in the network studies. Furthermore, we present the first scale-free network model, which was proposed by Barabási et al., and a modified model studied by Bianconi and Barabási, where now the preferential attachment incorporates the different ability (fitness) of the nodes to compete for links. At the end, our results, discussions and conclusions are presented

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In this work we elaborate and discuss a Complex Network model which presents connectivity scale free probability distribution (power-law degree distribution). In order to do that, we modify the rule of the preferential attachment of the Bianconi-Barabasi model, including a factor which represents the similarity of the sites. The term that corresponds to this similarity is called the affinity, and is obtained by the modulus of the difference between the fitness (or quality) of the sites. This variation in the preferential attachment generates very interesting results, by instance the time evolution of the connectivity, which follows a power-law distribution ki / ( t t0 )fi, where fi indicates the rate to the site gain connections. Certainly this depends on the affinity with other sites. Besides, we will show by numerical simulations results for the average path length and for the clustering coefficient

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In this work a study of social networks based on analysis of family names is presented. A basic approach to the mathematical formalism of graphs is developed and then main theoretical models for complex networks are presented aiming to support the analysis of surnames networks models. These, in turn, are worked so as to be drawn leading quantities, such as aggregation coefficient, minimum average path length and connectivity distribution. Based on these quantities, it can be stated that surnames networks are an example of complex network, showing important features such as preferential attachment and small-world character

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The subjective well- being (SWB) is formed by global judgments of satisfaction with life, or with peculiar domains the positive and the negative emotional experiences. The perception in turn, is the process of interpretive process of sensory data with cognitive or informative sense, absorbed in function of a context. From this perspective, the research aimed to evaluate SWB and the perception of advanced age pregnant women. Participated in the survey 80 pregnant with 35 years old or older (Group A or older) and 80 pregnant aged between 20 and 34 years old (Group B or young adults). The instruments used were: the scale of subjective well-being and a questionnaire, that included sociodemographic informations, items about pregnancy and a statement based on the Free Association of Words Technique (FAWT) to approach the perception of pregnancy. The data from the questionnaire and scale, in order to compare the data between groups suffered descriptive and inferential statistical analyzes. The analyzes performed with chi-square test among groups, which had values that were statistically significant, with the sociodemographic variables the type of contraceptive and health problems. The indicators of the SWB had further more by means in groups. The results of the Wilcoxon's test that there were no differences between the groups referred above. In the relation indicators of well being with variables age, education and income, some associations were significant. In addition, the words derived from the (FAWT) were analyzed using the software Programmer s Permenttant l´Analyse des Evocation (EVOC2000) and categorized according to content analysis of Bardin in three thematic categories (positive and negative affects, perception of gestation and implications of pregnancy) discussed as a group, since most of words were common. The study highlights shown how similar were the presented data by pregnant women surveyed. It is supposed about this fact the similarity is related to the social context. The relevance of this study for the health care network is to help with proposals aimed at specific improvements to the public and the sector, beside demonstrate that advanced age pregnant women and young adulst in the researched context showed no differences in the most of the studied characteristics