110 research outputs found
Tackling information asymmetry in networks: a new entropy-based ranking index
Information is a valuable asset for agents in socio-economic systems, a
significant part of the information being entailed into the very network of
connections between agents. The different interlinkages patterns that agents
establish may, in fact, lead to asymmetries in the knowledge of the network
structure; since this entails a different ability of quantifying relevant
systemic properties (e.g. the risk of financial contagion in a network of
liabilities), agents capable of providing a better estimate of (otherwise)
unaccessible network properties, ultimately have a competitive advantage. In
this paper, we address for the first time the issue of quantifying the
information asymmetry arising from the network topology. To this aim, we define
a novel index - InfoRank - intended to measure the quality of the information
possessed by each node, computing the Shannon entropy of the ensemble
conditioned on the node-specific information. Further, we test the performance
of our novel ranking procedure in terms of the reconstruction accuracy of the
(unaccessible) network structure and show that it outperforms other popular
centrality measures in identifying the "most informative" nodes. Finally, we
discuss the socio-economic implications of network information asymmetry.Comment: 12 pages, 8 figure
Cold and Warm Denaturation of Proteins
We introduce a simplified protein model where the water degrees of freedom
appear explicitly (although in an extremely simplified fashion). Using this
model we are able to recover both the warm and the cold protein denaturation
within a single framework, while addressing important issues about the
structure of model proteins
Putting Proteins back into Water
We introduce a simplified protein model where the solvent (water) degrees of
freedom appear explicitly (although in an extremely simplified fashion). Using
this model we are able to recover the thermodynamic phenomenology of proteins
over a wide range of temperatures. In particular we describe both the warm and
the {\it cold} protein denaturation within a single framework, while addressing
important issues about the structure of model proteins.Comment: 4 Pages, 4 Figures. To appear on PR
Preferential Exchange: Strengthening Connections in Complex Networks
Many social, technological and biological interactions involve network
relationships whose outcome intimately depends on the structure of the network
and on the strengths of the connections. Yet, although much information is now
available concerning the structure of many networks, the strengths are more
difficult to measure. Here we show that, for one particular social network,
notably the e-mail network, a suitable measure of the strength of the
connections can be available. We also propose a simple mechanism, based on
positive feedback and reciprocity, that can explain the observed behavior and
that hints toward specific dynamics of formation and reinforcement of network
connections. Network data from contexts different from social sciences indicate
that power-law, and generally broad, distributions of the connection strength
are ubiquitous, and the proposed mechanism has a wide range of applicability.Comment: 4 pages, 2 .eps figure
Sex-Oriented stable matchings of the Marriage Problem with correlated and incomplete information
In the Stable Marriage Problem two sets of agents must be paired according to
mutual preferences, which may happen to conflict. We present two
generalizations of its sex-oriented version, aiming to take into account
correlations between the preferences of agents and costly information. Their
effects are investigated both numerically and analytically.Comment: 5 pages, 2 figures, Proceedings of the NATO ARW on Application of
Physics in Economic Modelling, Prague 200
Uncovering the topology of configuration space networks
The configuration space network (CSN) of a dynamical system is an effective
approach to represent the ensemble of configurations sampled during a
simulation and their dynamic connectivity. To elucidate the connection between
the CSN topology and the underlying free-energy landscape governing the system
dynamics and thermodynamics, an analytical soluti on is provided to explain the
heavy tail of the degree distribution, neighbor co nnectivity and clustering
coefficient. This derivation allows to understand the universal CSN network
topology observed in systems ranging from a simple quadratic well to the native
state of the beta3s peptide and a 2D lattice heteropolymer. Moreover CSN are
shown to fall in the general class of complex networks describe d by the
fitness model.Comment: 6 figure
Matching games with partial information
We analyze different ways of pairing agents in a bipartite matching problem,
with regard to its scaling properties and to the distribution of individual
``satisfactions''. Then we explore the role of partial information and bounded
rationality in a generalized {\it Marriage Problem}, comparing the benefits
obtained by self-searching and by a matchmaker. Finally we propose a modified
matching game intended to mimic the way consumers' information makes firms to
enhance the quality of their products in a competitive market.Comment: 19 pages, 8 fig
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