90 research outputs found
Transmission of cultural traits in layered ego-centric networks
Although a number of models have been developed to investigate the emergence
of culture and evolutionary phases in social systems, one important aspect has
not yet been sufficiently emphasized. This is the structure of the underlaying
network of social relations serving as channels in transmitting cultural
traits, which is expected to play a crucial role in the evolutionary processes
in social systems. In this paper we contribute to the understanding of the role
of the network structure by developing a layered ego-centric network structure
based model, inspired by the social brain hypothesis, to study transmission of
cultural traits and their evolution in social network. For this model we first
find analytical results in the spirit of mean-field approximation and then to
validate the results we compare them with the results of extensive numerical
simulations.Comment: 10 pages, 2 figure
Scaling in public transport networks
We analyse the statistical properties of public transport networks. These
networks are defined by a set of public transport routes (bus lines) and the
stations serviced by these. For larger networks these appear to possess a
scale-free structure, as it is demonstrated e.g. by the Zipf law distribution
of the number of routes servicing a given station or for the distribution of
the number of stations which can be visited from the chosen one without
changing the means of transport. Moreover, a rather particular feature of the
public transport network is that many routes service common subsets of
stations. We discuss the possibility of new scaling laws that govern intrinsic
features of such subsets.Comment: 9 pages, 4 figure
Ground truth? Concept-based communities versus the external classification of physics manuscripts
Community detection techniques are widely used to infer hidden structures
within interconnected systems. Despite demonstrating high accuracy on
benchmarks, they reproduce the external classification for many real-world
systems with a significant level of discrepancy. A widely accepted reason
behind such outcome is the unavoidable loss of non-topological information
(such as node attributes) encountered when the original complex system is
represented as a network. In this article we emphasize that the observed
discrepancies may also be caused by a different reason: the external
classification itself. For this end we use scientific publication data which i)
exhibit a well defined modular structure and ii) hold an expert-made
classification of research articles. Having represented the articles and the
extracted scientific concepts both as a bipartite network and as its unipartite
projection, we applied modularity optimization to uncover the inner thematic
structure. The resulting clusters are shown to partly reflect the author-made
classification, although some significant discrepancies are observed. A
detailed analysis of these discrepancies shows that they carry essential
information about the system, mainly related to the use of similar techniques
and methods across different (sub)disciplines, that is otherwise omitted when
only the external classification is considered.Comment: 15 pages, 2 figure
Entropic equation of state and scaling functions near the critical point in scale-free networks
We analyze the entropic equation of state for a many-particle interacting
system in a scale-free network. The analysis is performed in terms of scaling
functions which are of fundamental interest in the theory of critical phenomena
and have previously been theoretically and experimentally explored in the
context of various magnetic, fluid, and superconducting systems in two and
three dimensions. Here, we obtain general scaling functions for the entropy,
the constant-field heat capacity, and the isothermal magnetocaloric coefficient
near the critical point in scale-free networks, where the node-degree
distribution exponent appears to be a global variable and plays a
crucial role, similar to the dimensionality for systems on lattices. This
extends the principle of universality to systems on scale-free networks and
allows quantification of the impact of fluctuations in the network structure on
critical behavior.Comment: 8 pages, 4 figure
Sex differences in intimate relationships
Social networks have turned out to be of fundamental importance both for our
understanding human sociality and for the design of digital communication
technology. However, social networks are themselves based on dyadic
relationships and we have little understanding of the dynamics of close
relationships and how these change over time. Evolutionary theory suggests
that, even in monogamous mating systems, the pattern of investment in close
relationships should vary across the lifespan when post-weaning investment
plays an important role in maximising fitness. Mobile phone data sets provide
us with a unique window into the structure of relationships and the way these
change across the lifespan. We here use data from a large national mobile phone
dataset to demonstrate striking sex differences in the pattern in the
gender-bias of preferred relationships that reflect the way the reproductive
investment strategies of the two sexes change across the lifespan: these
differences mainly reflect women's shifting patterns of investment in
reproduction and parental care. These results suggest that human social
strategies may have more complex dynamics than we have tended to assume and a
life-history perspective may be crucial for understanding them.Comment: 5 pages, 3 figures, contains electronic supplementary materia
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