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1 
Subdiffusive transport in nonhomogeneous media and nonlinear fractional equationsFalconer, Steven January 2015 (has links)
No description available.

2 
A Simulation Study of Walks in Large Social GraphsAnwar, Shahed 05 November 2015 (has links)
Online Social Networks (OSNs) such as Facebook, Twitter, and YouTube are among the most popular sites on the Internet. Billions of users are connected through these sites, building strong and effective communities to share views and ideas, and make recommendations nowadays. Therefore, by choosing an appropriate userbase from billions of people is required to analyze the structure and key characteristics of the large social graphs to improve current systems and to design new applications. For this reason, node sampling technique plays an important role to study largescale social networks. As a basic requirement, the sampled nodes and their links should possess similar statistical features of the original network, otherwise the conclusion drawn from the sampled network may not be appropriate for the entire population. Hence, good sampling strategies are key to many online social network applications. For instance, before introducing a new product or adding new feature(s) of a product to the online social network community, that specific new product or the additional feature has to be exposed to only a small set of users, who are carefully chosen to represent the complete set of users. As such, different random walkbased sampling techniques have been introduced to produce samples of nodes that not only are internally wellconnected but also capture the statistical features of the whole network. Traditionally, walkbased techniques do not have the restriction on the number of times that a node can be revisited while sampling. This may lead to an inefficient sampling method, because the walk may be "stuck" at a small number of highdegree nodes without being able to reach out to the rest of the nodes. A random walk, even after a large number of hops, may not be able to obtain a sampled network that captures the statistical features of the entire network.
In this thesis, we propose two walkbased sampling techniques to address the above problem, called KAvoiding Random Walk (KARW) and NeighborhoodAvoiding Random Walk (NARW). With KARW, the number of times that a node can be revisited is constrained within a given number K. With NARW, the random walk works in a "jump" fashion, since the walk starts outside of the Nhop neighborhood from the current node chosen randomly. By avoiding the current nodes neighboring area of levelN, NARW is expected to reach out the other nodes within the entire network quickly. We apply these techniques to construct multiple independent subgraphs from a social graph, consisting of 63K users with around a million connections between users collected from a Facebook dataset. By simulating our proposed strategies, we collect performance metrics and compare the results with the current stateoftheart sampling techniques (Uniform Random Sampling, Random Walk, and Metropolis Hastings Random Walk). We also calculate some of the key statistical features (i.e., degree distribution, betweenness centrality, closeness centrality, modularity, and clustering coefficient) of the sampled graphs to get an idea about the network structures that essentially represent the original social graph. / Graduate / 0984 / shahed.anwar@gmail.com

3 
Markov Chain Intersections and the LoopErased Walkrdlyons@indiana.edu 12 July 2001 (has links)
No description available.

4 
En slumpmässig vandring eller genomsnittlig återgång : Råder förutsägbarhet på Stockholmsbörsen?Alerius, Markus, Järlefelt, Daniel January 2014 (has links)
This study has been conducted in order to determine the existence of predictability for the Stockholm stock exchange. With this purpose the random walk theory has been raised against the theory of mean reversion in order to determine which theory is the most substantial. Data has been collected from Nasdaq OMX Nordic and furtherly been processed using the statistical software EViews. Swedish listed companies’ daily share values between 20002014 have been analyzed using two tests; an Augmented Dickey Fuller test and a Variance Ratio test. The results show generally that the null hypothesis  and thus the random walk  is rejected in the short term. This means that both on an aggregated level and on an individual level, the Stockholm stock exchange is predictable in the short term  in the form of mean reversion  and that it is most evident in small cap firms.

5 
Branching diffusionsHarris, Simon Colin January 1995 (has links)
No description available.

6 
A study of the efficiency of the foreign exchange market through analysis of ultrahigh frequency dataKanzler, Ludwig January 1998 (has links)
No description available.

7 
Networks: a random walk in degree space / Redes: um passeio aleatório no espaço dos grausAmpuero, Fernanda 18 May 2018 (has links)
The present work aims to contribute to the study of networks by mapping the temporal evolution of the degree to a random walk in degree space. We analyzed how and when the degree approximates a preestablished value through a parallel with the firstpassage problem of random walks. The mean time for the firstpassage was calculated for the dynamical versions the WattsStrogatz and ErdosRenyi models. We also analyzed the degree variance for the random recursive tree and BarabasiAlbert models / O presente trabalho visa contribuir com a pesquisa na área de redes através do mapeamento da evolução temporal do grau com um passeio aleatório no espaço do mesmo. Para tanto, foi feita uma análise de quando e como a quantidade de ligações do vértice se aproxima de um valor préestabelecido, mediante um paralelo com o problema da primeira passagem de passeios aleatórios. O tempo médio para a primeira passagem para as versões dinâmicas dos modelos WattsStrogatz e ErdosRényi foram calculados. Além disso, foi realizado um estudo da variância do grau para os modelos da árvore recursiva aleatória e BarabásiAlbert

8 
Networks: a random walk in degree space / Redes: um passeio aleatório no espaço dos grausFernanda Ampuero 18 May 2018 (has links)
The present work aims to contribute to the study of networks by mapping the temporal evolution of the degree to a random walk in degree space. We analyzed how and when the degree approximates a preestablished value through a parallel with the firstpassage problem of random walks. The mean time for the firstpassage was calculated for the dynamical versions the WattsStrogatz and ErdosRenyi models. We also analyzed the degree variance for the random recursive tree and BarabasiAlbert models / O presente trabalho visa contribuir com a pesquisa na área de redes através do mapeamento da evolução temporal do grau com um passeio aleatório no espaço do mesmo. Para tanto, foi feita uma análise de quando e como a quantidade de ligações do vértice se aproxima de um valor préestabelecido, mediante um paralelo com o problema da primeira passagem de passeios aleatórios. O tempo médio para a primeira passagem para as versões dinâmicas dos modelos WattsStrogatz e ErdosRényi foram calculados. Além disso, foi realizado um estudo da variância do grau para os modelos da árvore recursiva aleatória e BarabásiAlbert

9 
Random Walks on Trees with Finitely Many Cone TypesTatiana Nagnibeda, Wolfgang Woess, Andreas.Cap@esi.ac.at 07 March 2001 (has links)
No description available.

10 
Classification on the Average of Random WalksDaniela Bertacchi, Fabio Zucca, Andreas.Cap@esi.ac.at 26 April 2001 (has links)
No description available.

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