Random Graphs
Mostrando 13-24 de 28 artigos, teses e dissertações.
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13. Mixed H2 / H Infinity control through linear inequalities for flexible structures vibration reduction / Controle H2 / H Infinito via desigualdades matriciais lineares para atenuação de vibrações em estruturas flexiveis
This work has the goal to verify the action of a mixed H2/ Hoo control formulation through output feedback for a structure modelIed in finite elements. Therefore, the pure H2 and Hoo control formulations through output feedback are also verified to validate the described equations in this work for the mixed control and show a reference to their expected resu
Publicado em: 2005
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14. Quasi-random graphs
We introduce a large equivalence class of graph properties, all of which are shared by so-called random graphs. Unlike random graphs, however, it is often relatively easy to verify that a particular family of graphs possesses some property in this class.
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15. The average distances in random graphs with given expected degrees
Random graph theory is used to examine the “small-world phenomenon”; any two strangers are connected through a short chain of mutual acquaintances. We will show that for certain families of random graphs with given expected degrees the average distance is almost surely of order log n/log d̃, where d̃ is the weighted average of the sum of squares of the
National Academy of Sciences.
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16. Discrete-time random walks on diagrams (graphs) with cycles.
After a review of the diagram method for continuous-time random walks on graphs with cycles, the method is extended to discrete-time random walks. The basic theorems carry over formally from continuous time to discrete time. Three problems in tennis probabilities are used to illustrate random walks on discrete-time diagrams with cycles.
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17. Spectra of random graphs with given expected degrees
In the study of the spectra of power-law graphs, there are basically two competing approaches. One is to prove analogues of Wigner's semicircle law, whereas the other predicts that the eigenvalues follow a power-law distribution. Although the semicircle law and the power law have nothing in common, we will show that both approaches are essentially correc
National Academy of Sciences.
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18. Complexity and fragility in ecological networks.
A detailed analysis of three species-rich ecosystem food webs has shown that they display skewed distributions of connections. Such graphs of interaction are, in fact, shared by a number of biological and technological networks, which have been shown to display a very high homeostasis against random removals of nodes. Here, we analyse the responses of these
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19. Peak flow rate records in surveys: reproducibility of observers' reports.
Records of peak expiratory flow rate (PEFR), commonly used in hospital in the management of asthma, have not been evaluated as a method of identifying cases of asthma in population surveys. Four observers were asked to report on whether asthma was present or absent in 61 graphs of PEFR recorded two hourly for four weeks during surveys of working population.
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20. Subnets of scale-free networks are not scale-free: Sampling properties of networks
Most studies of networks have only looked at small subsets of the true network. Here, we discuss the sampling properties of a network's degree distribution under the most parsimonious sampling scheme. Only if the degree distributions of the network and randomly sampled subnets belong to the same family of probability distributions is it possible to extrapola
National Academy of Sciences.
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21. Random graph models of social networks
We describe some new exactly solvable models of the structure of social networks, based on random graphs with arbitrary degree distributions. We give models both for simple unipartite networks, such as acquaintance networks, and bipartite networks, such as affiliation networks. We compare the predictions of our models to data for a number of real-world socia
National Academy of Sciences.
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22. Further properties of random walks on diagrams (graphs) with and without cycles.
Three problems are considered. The first is the relation between ensemble-averaged state probabilities in a random walk with absorption and time-averaged state probabilities in the corresponding closed diagram. The second problem is concerned with random walks on diagrams with cycles in which the cycle completion rates and probabilities may depend on the "re
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23. Interpretation of Sucrose Gradient Sedimentation Pattern of Deoxyribonucleic Acid Fragments Resulting from Random Breaks
Mass distribution in a sucrose gradient of deoxyribonucleic acid (DNA) fragments arising as a result of random breaks is predicted by analytical means from which computer evaluations are plotted. The analytical results are compared with the results of verifying experiments: (i) a Monte Carlo computer experiment in which simulated molecules of DNA were indivi
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24. Win–stay, lose–shift in language learning from peers
Traditional language learning theory explores an idealized interaction between a teacher and a learner. The teacher provides sentences from a language, while the learner has to infer the underlying grammar. Here, we study a new approach by considering a population of individuals that learn from each other. There is no designated teacher. We are inspired by t
National Academy of Sciences.