Papers by Vittorio Loreto
The Evolution of Language - Proceedings of the 6th International Conference (EVOLANG6), 2006
Evolution of Communication and Language in Embodied Agents, 2009
In this chapter we explore several language games of increasing complexity. We first consider the... more In this chapter we explore several language games of increasing complexity. We first consider the so-called Naming Game, possibly the simplest example of the complex processes leading progressively to the establishment of human-like languages. In this framework, a globally shared vocabulary emerges as a result of local adjustments of individual word-meaning association. The emergence of a common vocabulary only represents
Proceedings of the National Academy of Sciences of the United States of America, Jan 30, 2007
Collaborative tagging has been quickly gaining ground because of its ability to recruit the activ... more Collaborative tagging has been quickly gaining ground because of its ability to recruit the activity of web users into effectively organizing and sharing vast amounts of information. Here we collect data from a popular system and investigate the statistical properties of tag cooccurrence. We introduce a stochastic model of user behavior embodying two main aspects of collaborative tagging: (i) a frequency-bias mechanism related to the idea that users are exposed to each other's tagging activity; (ii) a notion of memory, or aging of resources, in the form of a heavy-tailed access to the past state of the system. Remarkably, our simple modeling is able to account quantitatively for the observed experimental features with a surprisingly high accuracy. This points in the direction of a universal behavior of users who, despite the complexity of their own cognitive processes and the uncoordinated and selfish nature of their tagging activity, appear to follow simple activity patterns.
Physical review. E, Statistical, nonlinear, and soft matter physics, 2002
In this paper we investigate the possibility of a dynamical definition of an effective temperatur... more In this paper we investigate the possibility of a dynamical definition of an effective temperature for compacting granular media in the framework of the fluctuation-dissipation (FD) relations. We have studied two paradigmatic models for the compaction of granular media, which consider particles diffusing on a lattice, with either geometrical (tetris model) or dynamical (Kob-Andersen model) constraints. Idealized compaction without gravity has been implemented for the tetris model, and compaction with a preferential direction imposed by gravity has been studied for both models. In the ideal case of an homogeneous compaction, the obtained FD ratio is clearly shown to be in agreement with the prediction of Edwards' measure at various densities. Similar results are obtained with gravity only when the homogeneity of the bulk is imposed. In this case the FD ratio obtained dynamically for horizontal displacements and mobility and from Edwards' measure coincide. Finally, we propose ...
Physical review. E, Statistical, nonlinear, and soft matter physics, 2002
In this paper we report the measurement of a pseudotemperature for compacting granular media on t... more In this paper we report the measurement of a pseudotemperature for compacting granular media on the basis of the fluctuation-dissipation relations in the aging dynamics of a model system. From the violation of the fluctuation-dissipation theorem emerges an effective temperature (a dynamical temperature T(dyn)) whose value depends on the particle density. We compare the results for T(dyn) at several densities with the values of Edwards' compactivity at the corresponding densities [S. F. Edwards, in Granular Matter: An Interdisciplinary Approach, edited by A. Mehta (Springer-Verlag, New York, 1994) and references therein]. It turns out that the dynamical temperature and Edwards' compactivity coincide on a large range of densities, opening in this way the door to experimental checks as well as theoretical constructions.
Scientific Reports, 2014
Novelties are a familiar part of daily life. They are also fundamental to the evolution of biolog... more Novelties are a familiar part of daily life. They are also fundamental to the evolution of biological systems, human society and technology. By opening new possibilities, one novelty can pave the way for others in a process that Kauffman has called “expanding the adjacent possible”. The dynamics of correlated novelties, however, have yet to be quantified empirically or modeled mathematically. Here we propose a simple mathematical model that mimics the process of exploring a physical, biological, or conceptual space that enlarges whenever a novelty occurs. The model, a generalization of Polya's urn, predicts statistical laws for the rate at which novelties happen (Heaps' law) and for the probability distribution on the space explored (Zipf's law), as well as signatures of the process by which one novelty sets the stage for another. We test these predictions on four data sets of human activity: the edit events of Wikipedia pages, the emergence of tags in annotation systems...
An improved apparatus for dry spinning of filaments adapted to minimize the occurrence of oversiz... more An improved apparatus for dry spinning of filaments adapted to minimize the occurrence of oversized filaments during spinning. The apparatus includes a spinning pack positioned in a chamber supplied with heated gas. The spinning pack includes a distribution plate provided with a plurality of radial passages for gas, each passage having an opening at one end located at the periphery of the pack and an opening at the other end located at the bottom of the pack at the center of the extruded filament bundle to distribute heated gas from the outer chamber to the center of the filament bundle.
Proceedings of the National Academy of Sciences, 2008
Categories provide a coarse-grained description of the world. A fundamental question is whether c... more Categories provide a coarse-grained description of the world. A fundamental question is whether categories simply mirror an underlying structure of nature or instead come from the complex interactions of human beings among themselves and with the environment. Here, we address this question by modeling a population of individuals who co-evolve their own system of symbols and meanings by playing elementary language games. The central result is the emergence of a hierarchical category structure made of two distinct levels: a basic layer, responsible for fine discrimination of the environment, and a shared linguistic layer that groups together perceptions to guarantee communicative success. Remarkably, the number of linguistic categories turns out to be finite and small, as observed in natural languages.
Physical Review Letters, 2000
Physical Review Letters, 2002
Physical Review Letters, 2012
Physical Review Letters, 2003
New Journal of Physics, 2005
Journal of Statistical Mechanics: Theory and Experiment, 2006
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Papers by Vittorio Loreto