6 research outputs found
Emergence of scale-free leadership structure in social recommender systems
The study of the organization of social networks is important for
understanding of opinion formation, rumor spreading, and the emergence of
trends and fashion. This paper reports empirical analysis of networks extracted
from four leading sites with social functionality (Delicious, Flickr, Twitter
and YouTube) and shows that they all display a scale-free leadership structure.
To reproduce this feature, we propose an adaptive network model driven by
social recommending. Artificial agent-based simulations of this model highlight
a "good get richer" mechanism where users with broad interests and good
judgments are likely to become popular leaders for the others. Simulations also
indicate that the studied social recommendation mechanism can gradually improve
the user experience by adapting to tastes of its users. Finally we outline
implications for real online resource-sharing systems
Community structure and the evolution of interdisciplinarity in Slovenia's scientific collaboration network
Interaction among the scientific disciplines is of vital importance in modern
science. Focusing on the case of Slovenia, we study the dynamics of
interdisciplinary sciences from 1960 to 2010. Our approach relies on
quantifying the interdisciplinarity of research communities detected in the
coauthorship network of Slovenian scientists over time. Examining the evolution
of the community structure, we find that the frequency of interdisciplinary
research is only proportional with the overall growth of the network. Although
marginal improvements in favor of interdisciplinarity are inferable during the
70s and 80s, the overall trends during the past 20 years are constant and
indicative of stalemate. We conclude that the flow of knowledge between
different fields of research in Slovenia is in need of further stimulation.Comment: 11 pages, 4 figures; accepted for publication in PLoS ONE [related
work available at http://arxiv.org/abs/1004.4824 and
http://www.matjazperc.com/sicris/stats.html
Growth and structure of Slovenia's scientific collaboration network
We study the evolution of Slovenia's scientific collaboration network from
1960 till present with a yearly resolution. For each year the network was
constructed from publication records of Slovene scientists, whereby two were
connected if, up to the given year inclusive, they have coauthored at least one
paper together. Starting with no more than 30 scientists with an average of 1.5
collaborators in the year 1960, the network to date consists of 7380
individuals that, on average, have 10.7 collaborators. We show that, in spite
of the broad myriad of research fields covered, the networks form "small
worlds" and that indeed the average path between any pair of scientists scales
logarithmically with size after the largest component becomes large enough.
Moreover, we show that the network growth is governed by near-liner
preferential attachment, giving rise to a log-normal distribution of
collaborators per author, and that the average starting year is roughly
inversely proportional to the number of collaborators eventually acquired.
Understandably, not all that became active early have till now gathered many
collaborators. We also give results for the clustering coefficient and the
diameter of the network over time, and compare our conclusions with those
reported previously.Comment: 10 pages, 3 figures; accepted for publication in Journal of
Informetrics [related work available at http://arxiv.org/abs/1003.1018 and
http://www.matjazperc.com/sicris/stats.html