6,699 research outputs found
Hybrid Centrality Measures for Binary and Weighted Networks
Existing centrality measures for social network analysis suggest the
im-portance of an actor and give consideration to actor's given structural
position in a network. These existing measures suggest specific attribute of an
actor (i.e., popularity, accessibility, and brokerage behavior). In this study,
we propose new hybrid centrality measures (i.e., Degree-Degree,
Degree-Closeness and Degree-Betweenness), by combining existing measures (i.e.,
degree, closeness and betweenness) with a proposition to better understand the
importance of actors in a given network. Generalized set of measures are also
proposed for weighted networks. Our analysis of co-authorship networks dataset
suggests significant correlation of our proposed new centrality measures
(especially weighted networks) than traditional centrality measures with
performance of the scholars. Thus, they are useful measures which can be used
instead of traditional measures to show prominence of the actors in a network.Comment: a short version accepted in the 3rd workshop on Complex Network [Full
Paper submitted to JASIST in April 2011
Bank Networks from Text: Interrelations, Centrality and Determinants
In the wake of the still ongoing global financial crisis, bank
interdependencies have come into focus in trying to assess linkages among banks
and systemic risk. To date, such analysis has largely been based on numerical
data. By contrast, this study attempts to gain further insight into bank
interconnections by tapping into financial discourse. We present a
text-to-network process, which has its basis in co-occurrences of bank names
and can be analyzed quantitatively and visualized. To quantify bank importance,
we propose an information centrality measure to rank and assess trends of bank
centrality in discussion. For qualitative assessment of bank networks, we put
forward a visual, interactive interface for better illustrating network
structures. We illustrate the text-based approach on European Large and Complex
Banking Groups (LCBGs) during the ongoing financial crisis by quantifying bank
interrelations and centrality from discussion in 3M news articles, spanning
2007Q1 to 2014Q3.Comment: Quantitative Finance, forthcoming in 201
Numeric Input Relations for Relational Learning with Applications to Community Structure Analysis
Most work in the area of statistical relational learning (SRL) is focussed on
discrete data, even though a few approaches for hybrid SRL models have been
proposed that combine numerical and discrete variables. In this paper we
distinguish numerical random variables for which a probability distribution is
defined by the model from numerical input variables that are only used for
conditioning the distribution of discrete response variables. We show how
numerical input relations can very easily be used in the Relational Bayesian
Network framework, and that existing inference and learning methods need only
minor adjustments to be applied in this generalized setting. The resulting
framework provides natural relational extensions of classical probabilistic
models for categorical data. We demonstrate the usefulness of RBN models with
numeric input relations by several examples.
In particular, we use the augmented RBN framework to define probabilistic
models for multi-relational (social) networks in which the probability of a
link between two nodes depends on numeric latent feature vectors associated
with the nodes. A generic learning procedure can be used to obtain a
maximum-likelihood fit of model parameters and latent feature values for a
variety of models that can be expressed in the high-level RBN representation.
Specifically, we propose a model that allows us to interpret learned latent
feature values as community centrality degrees by which we can identify nodes
that are central for one community, that are hubs between communities, or that
are isolated nodes. In a multi-relational setting, the model also provides a
characterization of how different relations are associated with each community
Abusive Language Detection in Online Conversations by Combining Content-and Graph-based Features
In recent years, online social networks have allowed worldwide users to meet
and discuss. As guarantors of these communities, the administrators of these
platforms must prevent users from adopting inappropriate behaviors. This
verification task, mainly done by humans, is more and more difficult due to the
ever growing amount of messages to check. Methods have been proposed to
automatize this moderation process, mainly by providing approaches based on the
textual content of the exchanged messages. Recent work has also shown that
characteristics derived from the structure of conversations, in the form of
conversational graphs, can help detecting these abusive messages. In this
paper, we propose to take advantage of both sources of information by proposing
fusion methods integrating content-and graph-based features. Our experiments on
raw chat logs show that the content of the messages, but also of their dynamics
within a conversation contain partially complementary information, allowing
performance improvements on an abusive message classification task with a final
F-measure of 93.26%
Learning Reputation in an Authorship Network
The problem of searching for experts in a given academic field is hugely
important in both industry and academia. We study exactly this issue with
respect to a database of authors and their publications. The idea is to use
Latent Semantic Indexing (LSI) and Latent Dirichlet Allocation (LDA) to perform
topic modelling in order to find authors who have worked in a query field. We
then construct a coauthorship graph and motivate the use of influence
maximisation and a variety of graph centrality measures to obtain a ranked list
of experts. The ranked lists are further improved using a Markov Chain-based
rank aggregation approach. The complete method is readily scalable to large
datasets. To demonstrate the efficacy of the approach we report on an extensive
set of computational simulations using the Arnetminer dataset. An improvement
in mean average precision is demonstrated over the baseline case of simply
using the order of authors found by the topic models
ModuLand plug-in for Cytoscape: determination of hierarchical layers of overlapping network modules and community centrality
Summary: The ModuLand plug-in provides Cytoscape users an algorithm for
determining extensively overlapping network modules. Moreover, it identifies
several hierarchical layers of modules, where meta-nodes of the higher
hierarchical layer represent modules of the lower layer. The tool assigns
module cores, which predict the function of the whole module, and determines
key nodes bridging two or multiple modules. The plug-in has a detailed
JAVA-based graphical interface with various colouring options. The ModuLand
tool can run on Windows, Linux, or Mac OS. We demonstrate its use on protein
structure and metabolic networks. Availability: The plug-in and its user guide
can be downloaded freely from: http://www.linkgroup.hu/modules.php. Contact:
[email protected] Supplementary information: Supplementary
information is available at Bioinformatics online.Comment: 39 pages, 1 figure and a Supplement with 9 figures and 10 table
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