Polarización en redes sociales ayuda a que los influencers tengan más influencia: análisis y dos estrategias de inoculación

Este trabajo explora simulaciones de debates polarizados desde una premisa general y teórica. Específicamente, trata sobre la existencia de una vía verosímil para un subgrupo en una red social en línea para encontrar un desacuerdo beneficioso y cuál podría ser ese beneficio. Se propone un marco metodológico que representa los factores clave que impulsan la participación en las redes sociales, incluida la acumulación iterativa de influencia y la dinámica para el tratamiento asimétrico de mensajes durante un desacuerdo. Se muestra que, antes de un evento de polarización, se logra una tendencia hacia una distribución más uniforme de relativa influencia, lo que entonces se invierte por el evento de polarización. Se debaten las razones de esta reversión y cómo tiene un análogo verosímil en los sistemas del mundo real. Además, se propone un par de estrategias de inoculación, cuyo objetivo es devolver la tendencia hacia una influencia uniforme entre los usuarios, mientras que se abstiene de violar la privacidad del usuario (por mantener el tema agnóstico) y de las operaciones de eliminación de usuarios. &nbsp

Dynamic Katz and related network measures

We study walk-based centrality measures for time-ordered network sequences. For the case of standard dynamic walk-counting, we show how to derive and compute centrality measures induced by analytic functions. We also prove that dynamic Katz centrality, based on the resolvent function, has the unique advantage of allowing computations to be performed entirely at the node level. We then consider two distinct types of backtracking and develop a framework for capturing dynamic walk combinatorics when either or both is disallowed

Dynamic Katz and related network measures

We study walk-based centrality measures for time-ordered network sequences. For the case of standard dynamic walk-counting, we show how to derive and compute centrality measures induced by analytic functions. We also prove that dynamic Katz centrality, based on the resolvent function, has the unique advantage of allowing computations to be performed entirely at the node level. We then consider two distinct types of backtracking and develop a framework for capturing dynamic walk combinatorics when either or both is disallowed

Time-Dependent Influence Measurement in Citation Networks

In every scientific discipline, researchers face two common dilemmas: where to find bleeding-edge papers and where to publish their own articles. We propose to answer these questions by looking at the influence between communities, e.g. conferences or journals. The influential conferences are those which papers are heavily cited by other conferences, i.e. they are visible, significant and inspiring. For the task of finding such influential places-to-publish, we introduce a Running Influence model that aims to discover pairwise influence between communities and evaluate the overall influence of each considered community. We have taken into consideration time aspects such as intensity of papers citations over time and difference of conferences starting years. The community influence analysis is tested on real-world data of Computer Science conferences

DESCRIBING URGENT EVENT DIFFUSION ON TWITTER USING NETWORK STATISTICS

In this dissertation, I develop a novel framework to study the diffusion of urgent events through the popular social media platform—Twitter. Based on my literature review, this is the first comprehensive study on urgent event diffusion through Twitter. I observe similar diffusion patterns among different data sets and adopt the "cross prediction" mode to handle the early time prediction problem. I show that the statistics from the network of Twitter retweets can not only provide profound insights about event diffusion, but also can be used to effectively predict user influence and topic popularity. The above findings are consistent across various experiment settings. I also demonstrate that linear models consistently outperform state-of-art nonlinear ones in both user and hashtag prediction tasks, possibly implying the strong log-linear relationship between selected prediction features and the responses, which potentially could be a general phenomenon in the case of urgent event diffusion

Monitoring and Modelling of Social Networks

In this thesis we contribute to the understanding of online social networks, temporal networks, and non-equilibrium dynamics. As the title of this work suggests, this thesis is split into two parts, \emph{monitoring} and \emph{modelling} social networks. In the first half we look at current methods for understanding the behaviour and influence of individual users within a social network, and assess their robustness and effectiveness. In particular, we look at the role that the temporal dimension plays on these methods and the various representations that temporal networks can take. We introduce a new temporal network representation which describes a temporal network in terms of node behaviour which we use to characterise individuals and collectives. The new representation is illustrated with examples from the online social network Twitter. We model two particular aspects of social networks in the second half of this thesis. The first model, a generalisation of the popular Voter model, considers the dynamics of two opposite opinions in a heterogeneous society which differ by the resolve of their opinion. The second model investigates how the presence of `anti-bandwagon' agents can prevent the spread of ideas and innovations on a social network, particularly on networks with restrictive topologies. This contribution offers new ways to analyse temporal networks and online social media, and also provokes new and interesting questions for future research in the field

Discovering and validating influence in a dynamic online social network

Online human interactions take place within a dynamic hierarchy, where social influence is determined by qualities such as status, eloquence, trustworthiness, authority and persuasiveness. In this work, we consider topic-based twitter interaction networks, and address the task of identifying influential players. Our motivation is the strong desire of many commercial entities to increase their social media presence by engaging positively with pivotal bloggers and tweeters. After discussing some of the issues involved in extracting useful interaction data from a twitter feed, we define the concept of an active node subnetwork sequence. This provides a time-dependent, topic-based, summary of relevant twitter activity. For these types of transient interactions, it has been argued that the flow of information, and hence the influence of a node, is highly dependent on the timing of the links. Some nodes with relatively small bandwidth may turn out to be key players because of their prescience and their ability to instigate follow-on network activity. To simulate a commercial application, we build an active node subnetwork sequence based on key words in the area of travel and holidays. We then compare a range of network centrality measures, including a recently proposed version that accounts for the arrow of time, with respect to their ability to rank important nodes in this dynamic setting. The centrality rankings use only connectivity information (who tweeted whom, when), without requiring further information about the account type or message content, but if we post-process the results by examining account details, we find that the time-respecting, dynamic approach, which looks at the follow-on flow of information, is less likely to be ‘misled’ by accounts that appear to generate large numbers of automatic tweets with the aim of pushing out web links. We then benchmark these algorithmically derived rankings against independent feedback from five social media experts, given access to the full tweet content, who judge twitter accounts as part of their professional duties. We find that the dynamic centrality measures add value to the expert view, and can be hard to distinguish from an expert in terms of who they place in the top ten. These algorithms, which involve sparse matrix linear system solves with sparsity driven by the underlying network structure, can be applied to very large-scale networks. We also test an extension of the dynamic centrality measure that allows us to monitor the change in ranking, as a function of time, of the twitter accounts that were eventually deemed influential