baldassarri baronchelli barrat caglioti castellano cattuto complexity dattoli evolutionary_dynamics granular_media granular_media herrmann information_theory innovation_dynamics kreyon language_dynamics loreto mari mukherjee petri pietronero puglisi quantum_optics self_organization servedio statistical_physics techno_social_systems tria zapperi zippers
2017 |
, (Ed.) Copystree: gaming artificial phylogenies Periodical Capturing Phylogenetic Algorithms for Linguistics, 2017. Abstract | Links | BibTeX | Tags: kreyon, loreto @periodical{Pompei2017, title = {Copystree: gaming artificial phylogenies}, author = { Simone Pompei and Vittorio Loreto and Francesca Tria}, url = {http://www.socialdynamics.it/pubs/}, year = {2017}, date = {2017-01-01}, issuetitle = {Capturing Phylogenetic Algorithms for Linguistics}, journal = {Language Dynamics and Change}, abstract = {The reconstruction of phylogenies of cultural artefacts represents an open problem that mixes theoretical and computational challenges. Existing bench- marks rely on simulated phylogenies, where hypotheses on the underlying evolutionary mechanisms are unavoidable, or in real data phylogenies, for which no true evolutionary history is known. Here we introduce a web-based game, Copystree, where users create phylogenies of manuscripts, through successive copying actions, in a fully monitored setup. While players enjoy the experience, Copystree allows to build artificial phylogenies whose evolutionary processes do not obey to any pre-defined theoretical mechanisms, being generated instead with the unpredictability of human creativity. We present the analysis of the data gathered during the first set of experiments and use the artificial phylogenies gathered for a first test of existing phylogenetic algorithms.}, keywords = {kreyon, loreto}, pubstate = {published}, tppubtype = {periodical} } The reconstruction of phylogenies of cultural artefacts represents an open problem that mixes theoretical and computational challenges. Existing bench- marks rely on simulated phylogenies, where hypotheses on the underlying evolutionary mechanisms are unavoidable, or in real data phylogenies, for which no true evolutionary history is known. Here we introduce a web-based game, Copystree, where users create phylogenies of manuscripts, through successive copying actions, in a fully monitored setup. While players enjoy the experience, Copystree allows to build artificial phylogenies whose evolutionary processes do not obey to any pre-defined theoretical mechanisms, being generated instead with the unpredictability of human creativity. We present the analysis of the data gathered during the first set of experiments and use the artificial phylogenies gathered for a first test of existing phylogenetic algorithms. |
Rodi, Giovanna Chiara; Loreto, Vittorio; Tria, Francesca Search strategies of Wikipedia readers Journal Article PLOS ONE, 12 (2), pp. e0170746, 2017. Links | BibTeX | Tags: kreyon, loreto, tria @article{rodi2017search, title = {Search strategies of Wikipedia readers}, author = {Giovanna Chiara Rodi and Vittorio Loreto and Francesca Tria}, url = {http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0170746}, year = {2017}, date = {2017-01-01}, journal = {PLOS ONE}, volume = {12}, number = {2}, pages = {e0170746}, publisher = {Public Library of Science}, keywords = {kreyon, loreto, tria}, pubstate = {published}, tppubtype = {article} } |
2016 |
Thurner, Stefan 43 Visions for Complexity (Exploring Complexity) Book WSPC, 2016, ISBN: 978-981-3206-84-7. Abstract | Links | BibTeX | Tags: loreto @book{Thurner2016, title = {43 Visions for Complexity (Exploring Complexity)}, author = {Stefan Thurner}, url = {http://www.worldscientific.com/worldscibooks/10.1142/10360 https://www.amazon.com/43-Visions-Complexity-Exploring-ebook/dp/B01N3XIXCN}, isbn = {978-981-3206-84-7}, year = {2016}, date = {2016-11-04}, volume = {1}, publisher = {WSPC}, abstract = {Coping with the complexities of the social world in the 21st century requires deeper quantitative and predictive understanding. Forty-three internationally acclaimed scientists and thinkers share their vision for complexity science in the next decade in this invaluable book. Topics cover how complexity and big data science could help society to tackle the great challenges ahead, and how the newly established Complexity Science Hub Vienna might be a facilitator on this path.}, keywords = {loreto}, pubstate = {published}, tppubtype = {book} } Coping with the complexities of the social world in the 21st century requires deeper quantitative and predictive understanding. Forty-three internationally acclaimed scientists and thinkers share their vision for complexity science in the next decade in this invaluable book. Topics cover how complexity and big data science could help society to tackle the great challenges ahead, and how the newly established Complexity Science Hub Vienna might be a facilitator on this path. |
V Loreto VDP Servedio, SH Strogatz Tria F Dynamics on Expanding Spaces: Modeling the Emergence of Novelties Book Chapter Mirko Degli Esposti Eduardo G. Altmann, François Pachet (Ed.): Creativity and Universality in Language, pp. 59-83, Springer International Publishing, 2016, ISBN: 978-3-319-24401-3. Abstract | Links | BibTeX | Tags: adjacent possible, innovation_dynamics, kreyon, loreto, review, servedio, strogatz, tria @inbook{Loreto2016, title = {Dynamics on Expanding Spaces: Modeling the Emergence of Novelties}, author = {V Loreto, VDP Servedio, SH Strogatz, F Tria}, editor = {Mirko Degli Esposti, Eduardo G. Altmann, François Pachet}, url = {http://link.springer.com/chapter/10.1007%2F978-3-319-24403-7_5}, doi = {10.1007/978-3-319-24403-7_5}, isbn = {978-3-319-24401-3}, year = {2016}, date = {2016-05-19}, booktitle = {Creativity and Universality in Language}, pages = {59-83}, publisher = {Springer International Publishing}, series = {Lecture Notes in Morphogenesis}, abstract = {Novelties are part of our daily lives. We constantly adopt new technologies, conceive new ideas, meet new people, and experiment with new situations. Occasionally, we as individual, in a complicated cognitive and sometimes fortuitous process, come up with something that is not only new to us, but to our entire society so that what is a personal novelty can turn into an innovation at a global level. Innovations occur throughout social, biological, and technological systems and, though we perceive them as a very natural ingredient of our human experience, little is known about the processes determining their emergence. Still the statistical occurrence of innovations shows striking regularities that represent a starting point to get a deeper insight in the whole phenomenology. This paper represents a small step in that direction, focusing on reviewing the scientific attempts to effectively model the emergence of the new and its regularities, with an emphasis on more recent contributions: from the plain Simon’s model tracing back to the 1950s, to the newest model of Polya’s urn with triggering of one novelty by another. What seems to be key in the successful modeling schemes proposed so far is the idea of looking at evolution as a path in a complex space, physical, conceptual, biological, and technological, whose structure and topology get continuously reshaped and expanded by the occurrence of the new. Mathematically, it is very interesting to look at the consequences of the interplay between the “actual” and the “possible” and this is the aim of this short review.}, keywords = {adjacent possible, innovation_dynamics, kreyon, loreto, review, servedio, strogatz, tria}, pubstate = {published}, tppubtype = {inbook} } Novelties are part of our daily lives. We constantly adopt new technologies, conceive new ideas, meet new people, and experiment with new situations. Occasionally, we as individual, in a complicated cognitive and sometimes fortuitous process, come up with something that is not only new to us, but to our entire society so that what is a personal novelty can turn into an innovation at a global level. Innovations occur throughout social, biological, and technological systems and, though we perceive them as a very natural ingredient of our human experience, little is known about the processes determining their emergence. Still the statistical occurrence of innovations shows striking regularities that represent a starting point to get a deeper insight in the whole phenomenology. This paper represents a small step in that direction, focusing on reviewing the scientific attempts to effectively model the emergence of the new and its regularities, with an emphasis on more recent contributions: from the plain Simon’s model tracing back to the 1950s, to the newest model of Polya’s urn with triggering of one novelty by another. What seems to be key in the successful modeling schemes proposed so far is the idea of looking at evolution as a path in a complex space, physical, conceptual, biological, and technological, whose structure and topology get continuously reshaped and expanded by the occurrence of the new. Mathematically, it is very interesting to look at the consequences of the interplay between the “actual” and the “possible” and this is the aim of this short review. |
Tria, Francesca; Loreto, Vittorio; Servedio, Vito; Salikoko, Mufwene S Modeling The Emergence Of Creole Languages Inproceedings Roberts, S G; Cuskley, C; McCrohon, L; Barceló-Coblijn, L; Fehér, O; Verhoef, T (Ed.): The Evolution of Language: Proceedings of the 11th International Conference (EVOLANGX11), 2016. Abstract | Links | BibTeX | Tags: kreyon, language_dynamics, language_games, loreto, servedio, tria @inproceedings{evolang11_89, title = {Modeling The Emergence Of Creole Languages}, author = {Francesca Tria and Vittorio Loreto and Vito Servedio and S. Mufwene Salikoko}, editor = {S.G. Roberts and C. Cuskley and L. McCrohon and L. Barceló-Coblijn and O. Fehér and T. Verhoef}, url = {http://evolang.org/neworleans/papers/89.html}, year = {2016}, date = {2016-01-01}, booktitle = {The Evolution of Language: Proceedings of the 11th International Conference (EVOLANGX11)}, abstract = {Creole languages offer an invaluable opportunity to study the processes leading to the emergence and evolution of Language, thanks to the short - typically a few generations - and reasonably well defined time-scales involved in their emergence. Another well-known case of a very fast emergence of a Language, though referring to a much smaller population size and different ecological conditions, is that of the Nicaraguan Sign Language. What these two phenomena have in common is that in both cases what is emerging is a contact language, i.e., a language born out of the non-trivial interaction of two (or more) parent languages. This is a typical case of what is known in biology as horizontal transmission. In many well-documented cases, creoles emerged in large segregated sugarcane or rice plantations on which the slave labourers were the overwhelming majority. Lacking a common substrate language, slaves were naturally brought to shift to the economically and politically dominant European language (often referred to as the lexifier) to bootstrap an effective communication system among themselves. Here, we focus on the emergence of creole languages originated in the contacts of European colonists and slaves during the 17th and 18th centuries in exogenous plantation colonies of especially the Atlantic and Indian Ocean, where detailed census data are available. Those for several States of USA can be found at http://www.census.gov/history, while for Central America and the Caribbean can be found at http://www.jamaicanfamilysearch.com/Samples/1790al11.htm. Without entering in the details of the creole formation at a fine-grained linguistic level, we aim at uncovering some of the general mechanisms that determine the emergence of contact languages, and that successfully apply to the case of creole formation.}, keywords = {kreyon, language_dynamics, language_games, loreto, servedio, tria}, pubstate = {published}, tppubtype = {inproceedings} } Creole languages offer an invaluable opportunity to study the processes leading to the emergence and evolution of Language, thanks to the short - typically a few generations - and reasonably well defined time-scales involved in their emergence. Another well-known case of a very fast emergence of a Language, though referring to a much smaller population size and different ecological conditions, is that of the Nicaraguan Sign Language. What these two phenomena have in common is that in both cases what is emerging is a contact language, i.e., a language born out of the non-trivial interaction of two (or more) parent languages. This is a typical case of what is known in biology as horizontal transmission. In many well-documented cases, creoles emerged in large segregated sugarcane or rice plantations on which the slave labourers were the overwhelming majority. Lacking a common substrate language, slaves were naturally brought to shift to the economically and politically dominant European language (often referred to as the lexifier) to bootstrap an effective communication system among themselves. Here, we focus on the emergence of creole languages originated in the contacts of European colonists and slaves during the 17th and 18th centuries in exogenous plantation colonies of especially the Atlantic and Indian Ocean, where detailed census data are available. Those for several States of USA can be found at http://www.census.gov/history, while for Central America and the Caribbean can be found at http://www.jamaicanfamilysearch.com/Samples/1790al11.htm. Without entering in the details of the creole formation at a fine-grained linguistic level, we aim at uncovering some of the general mechanisms that determine the emergence of contact languages, and that successfully apply to the case of creole formation. |
Cuskley, Christine; Loreto, Vittorio The Emergence Of Rules And Exceptions In A Population Of Interacting Agents Inproceedings Roberts, S G; Cuskley, C; McCrohon, L; Barceló-Coblijn, L; Fehér, O; Verhoef, T (Ed.): The Evolution of Language: Proceedings of the 11th International Conference (EVOLANGX11), 2016. Abstract | Links | BibTeX | Tags: cuskley, kreyon, language_dynamics, language_games, loreto, modeling, rules @inproceedings{evolang11_119, title = {The Emergence Of Rules And Exceptions In A Population Of Interacting Agents}, author = {Christine Cuskley and Vittorio Loreto}, editor = {S.G. Roberts and C. Cuskley and L. McCrohon and L. Barceló-Coblijn and O. Fehér and T. Verhoef}, url = {http://evolang.org/neworleans/papers/119.html}, year = {2016}, date = {2016-01-01}, booktitle = {The Evolution of Language: Proceedings of the 11th International Conference (EVOLANGX11)}, abstract = {Rules are an efficient feature of natural languages which allow speakers to use a finite set of instructions to generate a virtually infinite set of utterances. Yet, for many regular rules, there are irregular exceptions. There has been lively debate in cognitive science about how individual learners acquire rules and exceptions; for example, how they learn the past tense of preach is preached, but for teach it is taught. In this paper, we take a different perspective, examining the dynamics of regularity and irregularity across a population of interacting agents to investigate how inflectional rules are applied to verbs. We show that in the absence of biases towards either regularity or irregularity, the outcome is determined by the initial condition, irrespective of the frequency of usage of the given lemma. On the other hand, in presence of biases, rule systems exhibit frequency dependent patterns in regularity reminiscent of patterns in natural language corpora. We examine the case where individuals are biased towards linguistic regularity in two ways: either as child learners, or through a memory constraint wherein irregular forms can only be remembered by an individual agent for a finite time period. We provide theoretical arguments for the prediction of a critical frequency below which irregularity cannot persist in terms of the duration of the finite time period which constrains agent memory.}, keywords = {cuskley, kreyon, language_dynamics, language_games, loreto, modeling, rules}, pubstate = {published}, tppubtype = {inproceedings} } Rules are an efficient feature of natural languages which allow speakers to use a finite set of instructions to generate a virtually infinite set of utterances. Yet, for many regular rules, there are irregular exceptions. There has been lively debate in cognitive science about how individual learners acquire rules and exceptions; for example, how they learn the past tense of preach is preached, but for teach it is taught. In this paper, we take a different perspective, examining the dynamics of regularity and irregularity across a population of interacting agents to investigate how inflectional rules are applied to verbs. We show that in the absence of biases towards either regularity or irregularity, the outcome is determined by the initial condition, irrespective of the frequency of usage of the given lemma. On the other hand, in presence of biases, rule systems exhibit frequency dependent patterns in regularity reminiscent of patterns in natural language corpora. We examine the case where individuals are biased towards linguistic regularity in two ways: either as child learners, or through a memory constraint wherein irregular forms can only be remembered by an individual agent for a finite time period. We provide theoretical arguments for the prediction of a critical frequency below which irregularity cannot persist in terms of the duration of the finite time period which constrains agent memory. |
Sakellariou, Jason; Tria, Francesca; Loreto, Vittorio; Pachet, François Maximum entropy models capture melodic styles Journal Article arXiv preprint arXiv:1610.03414, 2016. Abstract | Links | BibTeX | Tags: kreyon, loreto, tria @article{sakellariou2016maximum, title = {Maximum entropy models capture melodic styles}, author = {Jason Sakellariou and Francesca Tria and Vittorio Loreto and François Pachet}, url = {https://arxiv.org/abs/1610.03414}, year = {2016}, date = {2016-01-01}, journal = {arXiv preprint arXiv:1610.03414}, abstract = {We introduce a model for music generation where melodies are seen as a network of interacting notes. Starting from the principle of maximum entropy we assign to this network a probability distribution, which is learned from an existing musical corpus. We use this model to generate novel musical sequences that mimic the style of the corpus. Our main result is that this model can reproduce high-order patterns despite having a polynomial sample complexity. This is in contrast with the more traditionally used Markov models that have an exponential sample complexity.}, keywords = {kreyon, loreto, tria}, pubstate = {published}, tppubtype = {article} } We introduce a model for music generation where melodies are seen as a network of interacting notes. Starting from the principle of maximum entropy we assign to this network a probability distribution, which is learned from an existing musical corpus. We use this model to generate novel musical sequences that mimic the style of the corpus. Our main result is that this model can reproduce high-order patterns despite having a polynomial sample complexity. This is in contrast with the more traditionally used Markov models that have an exponential sample complexity. |
Thurner, Stefan 43 Visions for Complexity Book World Scientific, 2016. BibTeX | Tags: innovation_dynamics, kreyon, loreto @book{thurner201643, title = {43 Visions for Complexity}, author = {Stefan Thurner}, year = {2016}, date = {2016-01-01}, publisher = {World Scientific}, keywords = {innovation_dynamics, kreyon, loreto}, pubstate = {published}, tppubtype = {book} } |
2015 |
Mastroianni, Pierpaolo; Monechi, Bernardo; Liberto, Carlo; Valenti, Gaetano; Servedio, Vito DP; Loreto, Vittorio Local Optimization Strategies in Urban Vehicular Mobility Journal Article PloS one, 10 (12), pp. e0143799, 2015. Abstract | Links | BibTeX | Tags: GPS data, human mobility, kreyon, local optimization, loreto, monechi, servedio, urban network @article{Mastroianni2015, title = {Local Optimization Strategies in Urban Vehicular Mobility}, author = {Pierpaolo Mastroianni and Bernardo Monechi and Carlo Liberto and Gaetano Valenti and Vito DP Servedio and Vittorio Loreto}, url = {http://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0143799}, doi = {doi:10.1371/journal.pone.0143799}, year = {2015}, date = {2015-12-15}, journal = {PloS one}, volume = {10}, number = {12}, pages = {e0143799}, publisher = {Public Library of Science}, abstract = {The comprehension of vehicular traffic in urban environments is crucial to achieve a good management of the complex processes arising from people collective motion. Even allowing for the great complexity of human beings, human behavior turns out to be subject to strong constraints—physical, environmental, social, economic—that induce the emergence of common patterns. The observation and understanding of those patterns is key to setup effective strategies to optimize the quality of life in cities while not frustrating the natural need for mobility. In this paper we focus on vehicular mobility with the aim to reveal the underlying patterns and uncover the human strategies determining them. To this end we analyze a large dataset of GPS vehicles tracks collected in the Rome (Italy) district during a month. We demonstrate the existence of a local optimization of travel times that vehicle drivers perform while choosing their journey. This finding is mirrored by two additional important facts, i.e., the observation that the average vehicle velocity increases by increasing the travel length and the emergence of a universal scaling law for the distribution of travel times at fixed traveled length. A simple modeling scheme confirms this scenario opening the way to further predictions.}, keywords = {GPS data, human mobility, kreyon, local optimization, loreto, monechi, servedio, urban network}, pubstate = {published}, tppubtype = {article} } The comprehension of vehicular traffic in urban environments is crucial to achieve a good management of the complex processes arising from people collective motion. Even allowing for the great complexity of human beings, human behavior turns out to be subject to strong constraints—physical, environmental, social, economic—that induce the emergence of common patterns. The observation and understanding of those patterns is key to setup effective strategies to optimize the quality of life in cities while not frustrating the natural need for mobility. In this paper we focus on vehicular mobility with the aim to reveal the underlying patterns and uncover the human strategies determining them. To this end we analyze a large dataset of GPS vehicles tracks collected in the Rome (Italy) district during a month. We demonstrate the existence of a local optimization of travel times that vehicle drivers perform while choosing their journey. This finding is mirrored by two additional important facts, i.e., the observation that the average vehicle velocity increases by increasing the travel length and the emergence of a universal scaling law for the distribution of travel times at fixed traveled length. A simple modeling scheme confirms this scenario opening the way to further predictions. |
Rodi, Giovanna Chiara; Loreto, Vittorio; Servedio, Vito DP; Tria, Francesca Optimal Learning Paths in Information Networks Journal Article Scientific Reports, 5 (10286), 2015. Abstract | Links | BibTeX | Tags: innovation_dynamics, kreyon, learning_dynamics, loreto, rodi, servedio, tria @article{Rodi2015, title = {Optimal Learning Paths in Information Networks}, author = {Giovanna Chiara Rodi and Vittorio Loreto and Vito DP Servedio and Francesca Tria}, url = {http://www.nature.com/srep/2015/150601/srep10286/full/srep10286.html}, doi = {10.1038/srep10286}, year = {2015}, date = {2015-06-01}, journal = {Scientific Reports}, volume = {5}, number = {10286}, abstract = {Each sphere of knowledge and information could be depicted as a complex mesh of correlated items. By properly exploiting these connections, innovative and more efficient navigation strategies could be defined, possibly leading to a faster learning process and an enduring retention of information. In this work we investigate how the topological structure embedding the items to be learned can affect the efficiency of the learning dynamics. To this end we introduce a general class of algorithms that simulate the exploration of knowledge/information networks standing on well-established findings on educational scheduling, namely the spacing and lag effects. While constructing their learning schedules, individuals move along connections, periodically revisiting some concepts, and sometimes jumping on very distant ones. In order to investigate the effect of networked information structures on the proposed learning dynamics we focused both on synthetic and real-world graphs such as subsections of Wikipedia and word-association graphs. We highlight the existence of optimal topological structures for the simulated learning dynamics whose efficiency is affected by the balance between hubs and the least connected items. Interestingly, the real-world graphs we considered lead naturally to almost optimal learning performances.}, keywords = {innovation_dynamics, kreyon, learning_dynamics, loreto, rodi, servedio, tria}, pubstate = {published}, tppubtype = {article} } Each sphere of knowledge and information could be depicted as a complex mesh of correlated items. By properly exploiting these connections, innovative and more efficient navigation strategies could be defined, possibly leading to a faster learning process and an enduring retention of information. In this work we investigate how the topological structure embedding the items to be learned can affect the efficiency of the learning dynamics. To this end we introduce a general class of algorithms that simulate the exploration of knowledge/information networks standing on well-established findings on educational scheduling, namely the spacing and lag effects. While constructing their learning schedules, individuals move along connections, periodically revisiting some concepts, and sometimes jumping on very distant ones. In order to investigate the effect of networked information structures on the proposed learning dynamics we focused both on synthetic and real-world graphs such as subsections of Wikipedia and word-association graphs. We highlight the existence of optimal topological structures for the simulated learning dynamics whose efficiency is affected by the balance between hubs and the least connected items. Interestingly, the real-world graphs we considered lead naturally to almost optimal learning performances. |
Bernardo Monechi, Vito DP Servedio ; Loreto, Vittorio Congestion Transition in Air Traffic Networks Journal Article PLoS ONE, 10 (5), pp. e0125546, 2015. Abstract | Links | BibTeX | Tags: air traffic, complex_systems, loreto, monechi, servedio, transportation networks @article{Monechi2015, title = {Congestion Transition in Air Traffic Networks}, author = {Bernardo Monechi, Vito DP Servedio and Vittorio Loreto}, url = {http://dx.doi.org/10.1371%2Fjournal.pone.0125546}, doi = {10.1371/journal.pone.0125546}, year = {2015}, date = {2015-05-20}, journal = {PLoS ONE}, volume = {10}, number = {5}, pages = {e0125546}, abstract = {Air Transportation represents a very interesting example of a complex techno-social system whose importance has considerably grown in time and whose management requires a careful understanding of the subtle interplay between technological infrastructure and human behavior. Despite the competition with other transportation systems, a growth of air traffic is still foreseen in Europe for the next years. The increase of traffic load could bring the current Air Traffic Network above its capacity limits so that safety standards and performances might not be guaranteed anymore. Lacking the possibility of a direct investigation of this scenario, we resort to computer simulations in order to quantify the disruptive potential of an increase in traffic load. To this end we model the Air Transportation system as a complex dynamical network of flights controlled by humans who have to solve potentially dangerous conflicts by redirecting aircraft trajectories. The model is driven and validated through historical data of flight schedules in a European national airspace. While correctly reproducing actual statistics of the Air Transportation system, e.g., the distribution of delays, the model allows for theoretical predictions. Upon an increase of the traffic load injected in the system, the model predicts a transition from a phase in which all conflicts can be successfully resolved, to a phase in which many conflicts cannot be resolved anymore. We highlight how the current flight density of the Air Transportation system is well below the transition, provided that controllers make use of a special re-routing procedure. While the congestion transition displays a universal scaling behavior, its threshold depends on the conflict solving strategy adopted. Finally, the generality of the modeling scheme introduced makes it a flexible general tool to simulate and control Air Transportation systems in realistic and synthetic scenarios.}, keywords = {air traffic, complex_systems, loreto, monechi, servedio, transportation networks}, pubstate = {published}, tppubtype = {article} } Air Transportation represents a very interesting example of a complex techno-social system whose importance has considerably grown in time and whose management requires a careful understanding of the subtle interplay between technological infrastructure and human behavior. Despite the competition with other transportation systems, a growth of air traffic is still foreseen in Europe for the next years. The increase of traffic load could bring the current Air Traffic Network above its capacity limits so that safety standards and performances might not be guaranteed anymore. Lacking the possibility of a direct investigation of this scenario, we resort to computer simulations in order to quantify the disruptive potential of an increase in traffic load. To this end we model the Air Transportation system as a complex dynamical network of flights controlled by humans who have to solve potentially dangerous conflicts by redirecting aircraft trajectories. The model is driven and validated through historical data of flight schedules in a European national airspace. While correctly reproducing actual statistics of the Air Transportation system, e.g., the distribution of delays, the model allows for theoretical predictions. Upon an increase of the traffic load injected in the system, the model predicts a transition from a phase in which all conflicts can be successfully resolved, to a phase in which many conflicts cannot be resolved anymore. We highlight how the current flight density of the Air Transportation system is well below the transition, provided that controllers make use of a special re-routing procedure. While the congestion transition displays a universal scaling behavior, its threshold depends on the conflict solving strategy adopted. Finally, the generality of the modeling scheme introduced makes it a flexible general tool to simulate and control Air Transportation systems in realistic and synthetic scenarios. |
Colaiori, Francesca ; Castellano, Claudio ; Cuskley, Christine F; Loreto, Vittorio ; Pugliese, Martina ; Tria, Francesca General three-state model with biased population replacement: Analytical solution and application to language dynamics Journal Article Phys. Rev. E, 91 , pp. 012808, 2015. Links | BibTeX | Tags: castellano, colaiori, cuskley, language_dynamics, loreto, pugliese, tria @article{PhysRevE.91.012808, title = {General three-state model with biased population replacement: Analytical solution and application to language dynamics}, author = {Colaiori, Francesca and Castellano, Claudio and Cuskley, Christine F. and Loreto, Vittorio and Pugliese, Martina and Tria, Francesca}, url = {http://link.aps.org/doi/10.1103/PhysRevE.91.012808}, year = {2015}, date = {2015-01-01}, journal = {Phys. Rev. E}, volume = {91}, pages = {012808}, publisher = {American Physical Society}, keywords = {castellano, colaiori, cuskley, language_dynamics, loreto, pugliese, tria}, pubstate = {published}, tppubtype = {article} } |
Tria, Francesca; Servedio, Vito D P; Mufwene, Salikoko; Loreto, Vittorio Modeling the Emergence of Contact Languages Journal Article PLoS ONE, 10 (4), pp. e0120771, 2015. Abstract | Links | BibTeX | Tags: creoles, kreyon, language_dynamics, language_games, loreto, servedio, tria @article{10.1371/journal.pone.0120771, title = {Modeling the Emergence of Contact Languages}, author = {Francesca Tria and Vito D.P. Servedio and Salikoko Mufwene and Vittorio Loreto}, url = {http://dx.doi.org/10.1371%2Fjournal.pone.0120771}, doi = {10.1371/journal.pone.0120771}, year = {2015}, date = {2015-01-01}, journal = {PLoS ONE}, volume = {10}, number = {4}, pages = {e0120771}, publisher = {Public Library of Science}, abstract = { Contact languages are born out of the non-trivial interaction of two (or more) parent languages. Nowadays, the enhanced possibility of mobility and communication allows for a strong mixing of languages and cultures, thus raising the issue of whether there are any pure languages or cultures that are unaffected by contact with others. As with bacteria or viruses in biological evolution, the evolution of languages is marked by horizontal transmission; but to date no reliable quantitative tools to investigate these phenomena have been available. An interesting and well documented example of contact language is the emergence of creole languages, which originated in the contacts of European colonists and slaves during the 17th and 18th centuries in exogenous plantation colonies of especially the Atlantic and Indian Ocean. Here, we focus on the emergence of creole languages to demonstrate a dynamical process that mimics the process of creole formation in American and Caribbean plantation ecologies. Inspired by the Naming Game (NG), our modeling scheme incorporates demographic information about the colonial population in the framework of a non-trivial interaction network including three populations: Europeans, Mulattos/Creoles, and Bozal slaves. We show how this sole information makes it possible to discriminate territories that produced modern creoles from those that did not, with a surprising accuracy. The generality of our approach provides valuable insights for further studies on the emergence of languages in contact ecologies as well as to test specific hypotheses about the peopling and the population structures of the relevant territories. We submit that these tools could be relevant to addressing problems related to contact phenomena in many cultural domains: e.g., emergence of dialects, language competition and hybridization, globalization phenomena. },keywords = {creoles, kreyon, language_dynamics, language_games, loreto, servedio, tria}, pubstate = {published}, tppubtype = {article} } <p>Contact languages are born out of the non-trivial interaction of two (or more) parent languages. Nowadays, the enhanced possibility of mobility and communication allows for a strong mixing of languages and cultures, thus raising the issue of whether there are any pure languages or cultures that are unaffected by contact with others. As with bacteria or viruses in biological evolution, the evolution of languages is marked by horizontal transmission; but to date no reliable quantitative tools to investigate these phenomena have been available. An interesting and well documented example of contact language is the emergence of creole languages, which originated in the contacts of European colonists and slaves during the 17th and 18th centuries in exogenous plantation colonies of especially the Atlantic and Indian Ocean. Here, we focus on the emergence of creole languages to demonstrate a dynamical process that mimics the process of creole formation in American and Caribbean plantation ecologies. Inspired by the Naming Game (NG), our modeling scheme incorporates demographic information about the colonial population in the framework of a non-trivial interaction network including three populations: Europeans, Mulattos/Creoles, and Bozal slaves. We show how this sole information makes it possible to discriminate territories that produced modern creoles from those that did not, with a surprising accuracy. The generality of our approach provides valuable insights for further studies on the emergence of languages in contact ecologies as well as to test specific hypotheses about the peopling and the population structures of the relevant territories. We submit that these tools could be relevant to addressing problems related to contact phenomena in many cultural domains: e.g., emergence of dialects, language competition and hybridization, globalization phenomena.</p> |
Cuskley, Christine; Colaiori, Francesca; Castellano, Claudio; Loreto, Vittorio; Pugliese, Martina; Tria, Francesca The adoption of linguistic rules in native and non-native speakers: Evidence from a Wug task Journal Article Journal of Memory and Language, 84 , pp. 205 - 223, 2015, ISSN: 0749-596X. Abstract | Links | BibTeX | Tags: castellano, colaiori, cuskley, experiment, kreyon, language_dynamics, loreto, pugliese, rules, Sociolinguistics, tria @article{Cuskley2015205, title = {The adoption of linguistic rules in native and non-native speakers: Evidence from a Wug task}, author = {Christine Cuskley and Francesca Colaiori and Claudio Castellano and Vittorio Loreto and Martina Pugliese and Francesca Tria}, url = {http://www.sciencedirect.com/science/article/pii/S0749596X15000790}, doi = {http://dx.doi.org/10.1016/j.jml.2015.06.005}, issn = {0749-596X}, year = {2015}, date = {2015-01-01}, journal = {Journal of Memory and Language}, volume = {84}, pages = {205 - 223}, abstract = {Several recent theories have suggested that an increase in the number of non-native speakers in a language can lead to changes in morphological rules. We examine this experimentally by contrasting the performance of native and non-native English speakers in a simple Wug-task, showing that non-native speakers are significantly more likely to provide non -ed (i.e., irregular) past-tense forms for novel verbs than native speakers. Both groups are sensitive to sound similarities between new words and existing words (i.e., are more likely to provide irregular forms for novel words which sound similar to existing irregulars). Among both natives and non-natives, irregularizations are non-random; that is, rather than presenting as truly irregular inflectional strategies, they follow identifiable sub-rules present in the highly frequent set of irregular English verbs. Our results shed new light on how native and non-native learners can affect language structure.}, keywords = {castellano, colaiori, cuskley, experiment, kreyon, language_dynamics, loreto, pugliese, rules, Sociolinguistics, tria}, pubstate = {published}, tppubtype = {article} } Several recent theories have suggested that an increase in the number of non-native speakers in a language can lead to changes in morphological rules. We examine this experimentally by contrasting the performance of native and non-native English speakers in a simple Wug-task, showing that non-native speakers are significantly more likely to provide non -ed (i.e., irregular) past-tense forms for novel verbs than native speakers. Both groups are sensitive to sound similarities between new words and existing words (i.e., are more likely to provide irregular forms for novel words which sound similar to existing irregulars). Among both natives and non-natives, irregularizations are non-random; that is, rather than presenting as truly irregular inflectional strategies, they follow identifiable sub-rules present in the highly frequent set of irregular English verbs. Our results shed new light on how native and non-native learners can affect language structure. |
Colaiori, Francesca; Castellano, Claudio; Cuskley, Christine F; Loreto, Vittorio; Pugliese, Martina; Tria, Francesca General three-state model with biased population replacement: Analytical solution and application to language dynamics Journal Article Phys. Rev. E, 91 , pp. 012808, 2015. Abstract | Links | BibTeX | Tags: castellano, colaiori, cuskley, kreyon, language_dynamics, language_games, loreto, modeling, naming_game, pugliese, tria @article{PhysRevE.91.012808b, title = {General three-state model with biased population replacement: Analytical solution and application to language dynamics}, author = {Francesca Colaiori and Claudio Castellano and Christine F. Cuskley and Vittorio Loreto and Martina Pugliese and Francesca Tria}, url = {http://link.aps.org/doi/10.1103/PhysRevE.91.012808}, doi = {10.1103/PhysRevE.91.012808}, year = {2015}, date = {2015-01-01}, journal = {Phys. Rev. E}, volume = {91}, pages = {012808}, publisher = {American Physical Society}, abstract = {Empirical evidence shows that the rate of irregular usage of English verbs exhibits discontinuity as a function of their frequency: the most frequent verbs tend to be totally irregular. We aim to qualitatively understand the origin of this feature by studying simple agent-based models of language dynamics, where each agent adopts an inflectional state for a verb and may change it upon interaction with other agents. At the same time, agents are replaced at some rate by new agents adopting the regular form. In models with only two inflectional states (regular and irregular), we observe that either all verbs regularise irrespective of their frequency, or a continuous transition occurs between a low-frequency state, where the lemma becomes fully regular, and a high-frequency one, where both forms coexist. Introducing a third (mixed) state, wherein agents may use either form, we find that a third, qualitatively different behaviour may emerge, namely, a discontinuous transition in frequency. We introduce and solve analytically a very general class of three-state models that allows us to fully understand these behaviours in a unified framework. Realistic sets of interaction rules, including the well-known naming game (NG) model, result in a discontinuous transition, in agreement with recent empirical findings. We also point out that the distinction between speaker and hearer in the interaction has no effect on the collective behaviour. The results for the general three-state model, although discussed in terms of language dynamics, are widely applicable.}, keywords = {castellano, colaiori, cuskley, kreyon, language_dynamics, language_games, loreto, modeling, naming_game, pugliese, tria}, pubstate = {published}, tppubtype = {article} } Empirical evidence shows that the rate of irregular usage of English verbs exhibits discontinuity as a function of their frequency: the most frequent verbs tend to be totally irregular. We aim to qualitatively understand the origin of this feature by studying simple agent-based models of language dynamics, where each agent adopts an inflectional state for a verb and may change it upon interaction with other agents. At the same time, agents are replaced at some rate by new agents adopting the regular form. In models with only two inflectional states (regular and irregular), we observe that either all verbs regularise irrespective of their frequency, or a continuous transition occurs between a low-frequency state, where the lemma becomes fully regular, and a high-frequency one, where both forms coexist. Introducing a third (mixed) state, wherein agents may use either form, we find that a third, qualitatively different behaviour may emerge, namely, a discontinuous transition in frequency. We introduce and solve analytically a very general class of three-state models that allows us to fully understand these behaviours in a unified framework. Realistic sets of interaction rules, including the well-known naming game (NG) model, result in a discontinuous transition, in agreement with recent empirical findings. We also point out that the distinction between speaker and hearer in the interaction has no effect on the collective behaviour. The results for the general three-state model, although discussed in terms of language dynamics, are widely applicable. |
Baronchelli, Andrea; Loreto, Vittorio; Puglisi, Andrea Individual biases, cultural evolution, and the statistical nature of language universals: The case of colour naming systems Journal Article PloS one, 10 (5), pp. e0125019, 2015. Abstract | Links | BibTeX | Tags: kreyon, loreto @article{baronchelli2015individual, title = {Individual biases, cultural evolution, and the statistical nature of language universals: The case of colour naming systems}, author = {Andrea Baronchelli and Vittorio Loreto and Andrea Puglisi}, url = {http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0125019}, year = {2015}, date = {2015-01-01}, journal = {PloS one}, volume = {10}, number = {5}, pages = {e0125019}, publisher = {Public Library of Science}, abstract = {Language universals have long been attributed to an innate Universal Grammar. An alternative explanation states that linguistic universals emerged independently in every language in response to shared cognitive or perceptual biases. A computational model has recently shown how this could be the case, focusing on the paradigmatic example of the universal properties of colour naming patterns, and producing results in quantitative agreement with the experimental data. Here we investigate the role of an individual perceptual bias in the framework of the model. We study how, and to what extent, the structure of the bias influences the corresponding linguistic universal patterns. We show that the cultural history of a group of speakers introduces population-specific constraints that act against the pressure for uniformity arising from the individual bias, and we clarify the interplay between these two forces.}, keywords = {kreyon, loreto}, pubstate = {published}, tppubtype = {article} } Language universals have long been attributed to an innate Universal Grammar. An alternative explanation states that linguistic universals emerged independently in every language in response to shared cognitive or perceptual biases. A computational model has recently shown how this could be the case, focusing on the paradigmatic example of the universal properties of colour naming patterns, and producing results in quantitative agreement with the experimental data. Here we investigate the role of an individual perceptual bias in the framework of the model. We study how, and to what extent, the structure of the bias influences the corresponding linguistic universal patterns. We show that the cultural history of a group of speakers introduces population-specific constraints that act against the pressure for uniformity arising from the individual bias, and we clarify the interplay between these two forces. |
2014 |
Bernardo Monechi Vito DP Servedio, Vittorio Loreto Complex Networks and Transport Systems: Application to Air Transport and Urban Mobility PhD Thesis "Sapienza" University of Rome, 2014. Abstract | Links | BibTeX | Tags: air traffic, big data, complex network, GPS data, human mobility, local optimization, loreto, monechi, servedio, transportation network @phdthesis{MonechiPhDThesis2014, title = {Complex Networks and Transport Systems: Application to Air Transport and Urban Mobility}, author = {Bernardo Monechi, Vito DP Servedio, Vittorio Loreto}, url = {http://www.phys.uniroma1.it/fisica/sites/default/files/DOTT_FISICA/MENU/03DOTTORANDI/TesiFin27/Monechi.pdf}, year = {2014}, date = {2014-12-20}, address = {Piazzale Aldo Moro 5, 00185, Roma (RO), Italy}, school = {"Sapienza" University of Rome}, abstract = {This thesis is devoted to the study of transportation systems by means of Complex Systems and Complex Network Theories. Complex Networks are a tools of inestimable value in human transportation studies since in most of the cases the means of transportation used by individuals to move in space are bounded to move on a complex network. The topological properties of transportation networks can influence both the ability of individuals to move as well as their behavior in the environment, thus a characterization of the network is mandatory in order to understand the properties of the considered system. The two transportation systems that have been studied in this work are the Air Transport System and the mobility of cars in a urban environment. The analysis and modeling of the Air Transport System is the first and most extensive part of this thesis. In particular we will try to characterize and study the networks in which aircraft fly, exploiting these results to build a data-driven model of Air Traffic Control. The second part of the thesis is a continuation of the studies performed during by Pierpaolo Mastroianni during his Master Thesis. His work concerned the analysis of GPS tracks data in the City of Rome and the inference of statistical laws characterizing the behavior of car drivers. My contribution to his work is the development of a model capable of explaining some of the results presented in the Master Thesis.}, keywords = {air traffic, big data, complex network, GPS data, human mobility, local optimization, loreto, monechi, servedio, transportation network}, pubstate = {published}, tppubtype = {phdthesis} } This thesis is devoted to the study of transportation systems by means of Complex Systems and Complex Network Theories. Complex Networks are a tools of inestimable value in human transportation studies since in most of the cases the means of transportation used by individuals to move in space are bounded to move on a complex network. The topological properties of transportation networks can influence both the ability of individuals to move as well as their behavior in the environment, thus a characterization of the network is mandatory in order to understand the properties of the considered system. The two transportation systems that have been studied in this work are the Air Transport System and the mobility of cars in a urban environment. The analysis and modeling of the Air Transport System is the first and most extensive part of this thesis. In particular we will try to characterize and study the networks in which aircraft fly, exploiting these results to build a data-driven model of Air Traffic Control. The second part of the thesis is a continuation of the studies performed during by Pierpaolo Mastroianni during his Master Thesis. His work concerned the analysis of GPS tracks data in the City of Rome and the inference of statistical laws characterizing the behavior of car drivers. My contribution to his work is the development of a model capable of explaining some of the results presented in the Master Thesis. |
Bernardo Monechi Vito DP Servedio, Vittorio Loreto An Air Traffic Control Model Based Local Optimization over the Airways Network Inproceedings Schaefer, Dirk (Ed.): Proceedings of the SESAR Innovation Days (2014), EUROCONTROL 2014, ISBN: 978-2-87497-077-1. Abstract | Links | BibTeX | Tags: air traffic, extremal optimization, local optimization, loreto, monechi, servedio, transportation networks @inproceedings{Monechi2014, title = {An Air Traffic Control Model Based Local Optimization over the Airways Network}, author = {Bernardo Monechi, Vito DP Servedio, Vittorio Loreto}, editor = {Dirk Schaefer}, url = {http://www.sesarinnovationdays.eu/sites/default/files/media/SIDs/SID%202014-04.pdf}, isbn = {978-2-87497-077-1}, year = {2014}, date = {2014-11-25}, booktitle = {Proceedings of the SESAR Innovation Days (2014)}, organization = {EUROCONTROL}, abstract = {The introduction of a new SESAR scenario in the European Airspace will impact the functioning and the performances of the current Air Traffic Management (ATM) System. The understanding of the features and the limits of the current system could be crucial in order to improve and design the structure of the future ATM. In this paper we present some results of the "Assessment of Critical Delay Patterns and Avalanche Dynamics” PhD project from the ComplexWorld Network. During this project we developed a model of Air Traffic Control (ATC) based on Complex Network theory capable of reproducing the features of the real ATC in three European National Airspaces. We then developed an optimization algorithm based on “Extremal Optimization” in order to build efficient and globally optimized planned trajectories. The ATC model is applied in order to study the efficiency of this new planned trajectories when subject to external perturbations and to compare them to the current situation.}, keywords = {air traffic, extremal optimization, local optimization, loreto, monechi, servedio, transportation networks}, pubstate = {published}, tppubtype = {inproceedings} } The introduction of a new SESAR scenario in the European Airspace will impact the functioning and the performances of the current Air Traffic Management (ATM) System. The understanding of the features and the limits of the current system could be crucial in order to improve and design the structure of the future ATM. In this paper we present some results of the "Assessment of Critical Delay Patterns and Avalanche Dynamics” PhD project from the ComplexWorld Network. During this project we developed a model of Air Traffic Control (ATC) based on Complex Network theory capable of reproducing the features of the real ATC in three European National Airspaces. We then developed an optimization algorithm based on “Extremal Optimization” in order to build efficient and globally optimized planned trajectories. The ATC model is applied in order to study the efficiency of this new planned trajectories when subject to external perturbations and to compare them to the current situation. |
Loreto, Vittorio; Tria, Francesca Language games: Comment on "Modelling language evolution: Examples and predictions" by Tao Gong, Lan Shuai, Menghan Zhang Journal Article Physics of Life Reviews, 11 (2), pp. 311 - 312, 2014, ISSN: 1571-0645. Links | BibTeX | Tags: language_dynamics, loreto, tria @article{Loreto_2014_physics_life, title = {Language games: Comment on "Modelling language evolution: Examples and predictions" by Tao Gong, Lan Shuai, Menghan Zhang}, author = {Vittorio Loreto and Francesca Tria}, url = {http://www.sciencedirect.com/science/article/pii/S1571064514000074}, issn = {1571-0645}, year = {2014}, date = {2014-01-01}, journal = {Physics of Life Reviews}, volume = {11}, number = {2}, pages = {311 - 312}, keywords = {language_dynamics, loreto, tria}, pubstate = {published}, tppubtype = {article} } |
Cuskley, Christine F; Pugliese, Martina; Castellano, Claudio; Colaiori, Francesca; Loreto, Vittorio; Tria, Francesca Internal and External Dynamics in Language: Evidence from Verb Regularity in a Historical Corpus of English Journal Article PLoS ONE, 9 , 2014. Abstract | Links | BibTeX | Tags: castellano, colaiori, cuskley, language_dynamics, loreto, pugliese, tria @article{, title = {Internal and External Dynamics in Language: Evidence from Verb Regularity in a Historical Corpus of English}, author = {Christine F. Cuskley and Martina Pugliese and Claudio Castellano and Francesca Colaiori and Vittorio Loreto and Francesca Tria}, url = {http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0102882}, year = {2014}, date = {2014-01-01}, journal = {PLoS ONE}, volume = {9}, publisher = {Public Library of Science}, abstract = {Human languages are rule governed, but almost invariably these rules have exceptions in the form of irregularities. Since rules in language are efficient and productive, the persistence of irregularity is an anomaly. How does irregularity linger in the face of internal (endogenous) and external (exogenous) pressures to conform to a rule? Here we address this problem by taking a detailed look at simple past tense verbs in the Corpus of Historical American English. The data show that the language is open, with many new verbs entering. At the same time, existing verbs might tend to regularize or irregularize as a consequence of internal dynamics, but overall, the amount of irregularity sustained by the language stays roughly constant over time. Despite continuous vocabulary growth, and presumably, an attendant increase in expressive power, there is no corresponding growth in irregularity. We analyze the set of irregulars, showing they may adhere to a set of minority rules, allowing for increased stability of irregularity over time. These findings contribute to the debate on how language systems become rule governed, and how and why they sustain exceptions to rules, providing insight into the interplay between the emergence and maintenance of rules and exceptions in language. © 2014 Cuskley et al.}, keywords = {castellano, colaiori, cuskley, language_dynamics, loreto, pugliese, tria}, pubstate = {published}, tppubtype = {article} } Human languages are rule governed, but almost invariably these rules have exceptions in the form of irregularities. Since rules in language are efficient and productive, the persistence of irregularity is an anomaly. How does irregularity linger in the face of internal (endogenous) and external (exogenous) pressures to conform to a rule? Here we address this problem by taking a detailed look at simple past tense verbs in the Corpus of Historical American English. The data show that the language is open, with many new verbs entering. At the same time, existing verbs might tend to regularize or irregularize as a consequence of internal dynamics, but overall, the amount of irregularity sustained by the language stays roughly constant over time. Despite continuous vocabulary growth, and presumably, an attendant increase in expressive power, there is no corresponding growth in irregularity. We analyze the set of irregulars, showing they may adhere to a set of minority rules, allowing for increased stability of irregularity over time. These findings contribute to the debate on how language systems become rule governed, and how and why they sustain exceptions to rules, providing insight into the interplay between the emergence and maintenance of rules and exceptions in language. © 2014 Cuskley et al. |
Tria, Francesca; Loreto, Vittorio; Servedio, Vito Domenico Pietro; Strogatz, Steven H The dynamics of correlated novelties Journal Article SCIENTIFIC REPORTS, 4 , 2014. Abstract | Links | BibTeX | Tags: innovation_dynamics, loreto, servedio, strogatz, tria @article{b, title = {The dynamics of correlated novelties}, author = {Francesca Tria and Vittorio Loreto and Vito Domenico Pietro Servedio and Steven H. Strogatz}, url = {http://www.nature.com/srep/2014/140731/srep05890/full/srep05890.html}, year = {2014}, date = {2014-01-01}, journal = {SCIENTIFIC REPORTS}, volume = {4}, publisher = {Nature Publishing Group}, abstract = {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, the sequence of words in texts, and listening to new songs in online music catalogues. By quantifying the dynamics of correlated novelties, our results provide a starting point for a deeper understanding of the adjacent possible and its role in biological, cultural, and technological evolution.}, keywords = {innovation_dynamics, loreto, servedio, strogatz, tria}, pubstate = {published}, tppubtype = {article} } 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, the sequence of words in texts, and listening to new songs in online music catalogues. By quantifying the dynamics of correlated novelties, our results provide a starting point for a deeper understanding of the adjacent possible and its role in biological, cultural, and technological evolution. |
2013 |
Becker, Martin; Caminiti, Saverio; Fiorella, Donato; Francis, Louise; Gravino, Pietro; Haklay, Mordechai; Hotho, Andreas; Loreto, Vittorio; Mueller, Juergen; Ricchiuti, Ferdinando; Servedio, Vito D P; Sirbu, Alina; Tria, Francesca Awareness and learning in participatory noise sensing Journal Article PLoS ONE, 8 , pp. e81638-1–e81638-12, 2013. Abstract | Links | BibTeX | Tags: citizen_science, loreto, servedio, sirbu, tria @article{b, title = {Awareness and learning in participatory noise sensing}, author = {Martin Becker and Saverio Caminiti and Donato Fiorella and Louise Francis and Pietro Gravino and Mordechai Haklay and Andreas Hotho and Vittorio Loreto and Juergen Mueller and Ferdinando Ricchiuti and Vito D.P. Servedio and Alina Sirbu and Francesca Tria}, url = {http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0081638}, year = {2013}, date = {2013-01-01}, journal = {PLoS ONE}, volume = {8}, pages = {e81638-1--e81638-12}, abstract = {The development of ICT infrastructures has facilitated the emergence of new paradigms for looking at society and the environment over the last few years. Participatory environmental sensing, i.e. directly involving citizens in environmental monitoring, is one example, which is hoped to encourage learning and enhance awareness of environmental issues. In this paper, an analysis of the behaviour of individuals involved in noise sensing is presented. Citizens have been involved in noise measuring activities through the WideNoise smartphone application. This application has been designed to record both objective (noise samples) and subjective (opinions, feelings) data. The application has been open to be used freely by anyone and has been widely employed worldwide. In addition, several test cases have been organised in European countries. Based on the information submitted by users, an analysis of emerging awareness and learning is performed. The data show that changes in the way the environment is perceived after repeated usage of the application do appear. Specifically, users learn how to recognise different noise levels they are exposed to. Additionally, the subjective data collected indicate an increased user involvement in time and a categorisation effect between pleasant and less pleasant environments.}, keywords = {citizen_science, loreto, servedio, sirbu, tria}, pubstate = {published}, tppubtype = {article} } The development of ICT infrastructures has facilitated the emergence of new paradigms for looking at society and the environment over the last few years. Participatory environmental sensing, i.e. directly involving citizens in environmental monitoring, is one example, which is hoped to encourage learning and enhance awareness of environmental issues. In this paper, an analysis of the behaviour of individuals involved in noise sensing is presented. Citizens have been involved in noise measuring activities through the WideNoise smartphone application. This application has been designed to record both objective (noise samples) and subjective (opinions, feelings) data. The application has been open to be used freely by anyone and has been widely employed worldwide. In addition, several test cases have been organised in European countries. Based on the information submitted by users, an analysis of emerging awareness and learning is performed. The data show that changes in the way the environment is perceived after repeated usage of the application do appear. Specifically, users learn how to recognise different noise levels they are exposed to. Additionally, the subjective data collected indicate an increased user involvement in time and a categorisation effect between pleasant and less pleasant environments. |
Sirbu, Alina; Loreto, Vittorio; Servedio, Vito Domenico Pietro; Tria, Francesca Cohesion, consensus and extreme information in opinion dynamics Journal Article ADVANCES IN COMPLEX SYSTEM, 16 , 2013. Abstract | Links | BibTeX | Tags: loreto, opinion_dynamics, servedio, sirbu, tria @article{b, title = {Cohesion, consensus and extreme information in opinion dynamics}, author = {Alina Sirbu and Vittorio Loreto and Vito Domenico Pietro Servedio and Francesca Tria}, url = {http://www.worldscientific.com/doi/abs/10.1142/S0219525913500355}, year = {2013}, date = {2013-01-01}, journal = {ADVANCES IN COMPLEX SYSTEM}, volume = {16}, publisher = {WORLD SCIENTIFIC PUBL CO PTE LTD}, abstract = {Opinion formation is an important element of social dynamics. It has been widely studied in the last years with tools from physics, mathematics and computer science. Here, a continuous model of opinion dynamics for multiple possible choices is analyzed. Its main features are the inclusion of disagreement and possibility of modulating external information/media effects, both from one and multiple sources. The interest is in identifying the effect of the initial cohesion of the population, the interplay between cohesion and media extremism, and the effect of using multiple external sources of information that can influence the system. Final consensus, especially with the external message, depends highly on these factors, as numerical simulations show. When no external input is present, consensus or segregation is determined by the initial cohesion of the population. Interestingly, when only one external source of information is present, consensus can be obtained, in general, only when this is extremely neutral, i.e., there is not a single opinion strongly promoted, or in the special case of a large initial cohesion and low exposure to the external message. On the contrary, when multiple external sources are allowed, consensus can emerge with one of them even when this is not extremely neutral, i.e., it carries a strong message, for a large range of initial conditions.}, keywords = {loreto, opinion_dynamics, servedio, sirbu, tria}, pubstate = {published}, tppubtype = {article} } Opinion formation is an important element of social dynamics. It has been widely studied in the last years with tools from physics, mathematics and computer science. Here, a continuous model of opinion dynamics for multiple possible choices is analyzed. Its main features are the inclusion of disagreement and possibility of modulating external information/media effects, both from one and multiple sources. The interest is in identifying the effect of the initial cohesion of the population, the interplay between cohesion and media extremism, and the effect of using multiple external sources of information that can influence the system. Final consensus, especially with the external message, depends highly on these factors, as numerical simulations show. When no external input is present, consensus or segregation is determined by the initial cohesion of the population. Interestingly, when only one external source of information is present, consensus can be obtained, in general, only when this is extremely neutral, i.e., there is not a single opinion strongly promoted, or in the special case of a large initial cohesion and low exposure to the external message. On the contrary, when multiple external sources are allowed, consensus can emerge with one of them even when this is not extremely neutral, i.e., it carries a strong message, for a large range of initial conditions. |
Taggi, Lorenzo; Colaiori, Francesca; Loreto, Vittorio; Tria, Francesca Dynamical correlations in the escape strategy of Influenza A virus Journal Article EUROPHYSICS LETTERS, 101 , 2013. Abstract | BibTeX | Tags: biology, colaiori, evolutionary_dynamics, loreto, taggi, tria @article{b, title = {Dynamical correlations in the escape strategy of Influenza A virus}, author = {Lorenzo Taggi and Francesca Colaiori and Vittorio Loreto and Francesca Tria}, year = {2013}, date = {2013-01-01}, journal = {EUROPHYSICS LETTERS}, volume = {101}, abstract = {The evolutionary dynamics of human Influenza A virus presents a challenging theoretical problem. An extremely high mutation rate allows the virus to escape, at each epidemic season, the host immune protection elicited by previous infections. At the same time, at each given epidemic season a single quasi-species, that is a set of closely related strains, is observed. A non-trivial relation between the genetic (i.e., at the sequence level) and the antigenic (i.e., related to the host immune response) distances can shed light into this puzzle. In this paper we introduce a model in which, in accordance with experimental observations, a simple interaction rule based on spatial correlations among point mutations dynamically defines an immunity space in the space of sequences. We investigate the static and dynamic structure of this space and we discuss how it affects the dynamics of the virus-host interaction. Interestingly we observe a staggered time structure in the virus evolution as in the real Influenza evolutionary dynamics. © Copyright EPLA, 2013.}, keywords = {biology, colaiori, evolutionary_dynamics, loreto, taggi, tria}, pubstate = {published}, tppubtype = {article} } The evolutionary dynamics of human Influenza A virus presents a challenging theoretical problem. An extremely high mutation rate allows the virus to escape, at each epidemic season, the host immune protection elicited by previous infections. At the same time, at each given epidemic season a single quasi-species, that is a set of closely related strains, is observed. A non-trivial relation between the genetic (i.e., at the sequence level) and the antigenic (i.e., related to the host immune response) distances can shed light into this puzzle. In this paper we introduce a model in which, in accordance with experimental observations, a simple interaction rule based on spatial correlations among point mutations dynamically defines an immunity space in the space of sequences. We investigate the static and dynamic structure of this space and we discuss how it affects the dynamics of the virus-host interaction. Interestingly we observe a staggered time structure in the virus evolution as in the real Influenza evolutionary dynamics. © Copyright EPLA, 2013. |
Tria, Francesca; Pompei, Simone; Loreto, Vittorio Dynamically correlated mutations drive human Influenza A evolution Journal Article SCIENTIFIC REPORTS, 3 , 2013. Abstract | Links | BibTeX | Tags: biology, evolutionary_dynamics, loreto, pompei, tria @article{b, title = {Dynamically correlated mutations drive human Influenza A evolution}, author = {Francesca Tria and Simone Pompei and Vittorio Loreto}, url = {http://www.nature.com/srep/2013/130919/srep02705/full/srep02705.html}, year = {2013}, date = {2013-01-01}, journal = {SCIENTIFIC REPORTS}, volume = {3}, publisher = {NATURE PUBLISHING GROUP}, abstract = {Human Influenza A virus undergoes recurrent changes in the hemagglutinin (HA) surface protein, primarily involved in the human antibody recognition. Relevant antigenic changes, enabling the virus to evade host immune response, have been recognized to occur in parallel to multiple mutations at antigenic sites in HA. Yet, the role of correlated mutations (epistasis) in driving the molecular evolution of the virus still represents a challenging puzzle. Further, though circulation at a global geographic level is key for the survival of Influenza A, its role in shaping the viral phylodynamics remains largely unexplored. Here we show, through a sequence based epidemiological model, that epistatic effects between amino acids substitutions, coupled with a reservoir that mimics worldwide circulating viruses, are key determinants that drive human Influenza A evolution. Our approach explains all the up-to-date observations characterizing the evolution of H3N2 subtype, including phylogenetic properties, nucleotide fixation patterns, and composition of antigenic clusters.}, keywords = {biology, evolutionary_dynamics, loreto, pompei, tria}, pubstate = {published}, tppubtype = {article} } Human Influenza A virus undergoes recurrent changes in the hemagglutinin (HA) surface protein, primarily involved in the human antibody recognition. Relevant antigenic changes, enabling the virus to evade host immune response, have been recognized to occur in parallel to multiple mutations at antigenic sites in HA. Yet, the role of correlated mutations (epistasis) in driving the molecular evolution of the virus still represents a challenging puzzle. Further, though circulation at a global geographic level is key for the survival of Influenza A, its role in shaping the viral phylodynamics remains largely unexplored. Here we show, through a sequence based epidemiological model, that epistatic effects between amino acids substitutions, coupled with a reservoir that mimics worldwide circulating viruses, are key determinants that drive human Influenza A evolution. Our approach explains all the up-to-date observations characterizing the evolution of H3N2 subtype, including phylogenetic properties, nucleotide fixation patterns, and composition of antigenic clusters. |
Maity, Suman Kalyan; Mukherjee, Animesh; Tria, Francesca; Loreto, Vittorio Emergence of fast agreement in an overhearing population: The case of the naming game Journal Article EUROPHYSICS LETTERS, 101 , 2013. Abstract | BibTeX | Tags: language_dynamics, loreto, mukherjee, tria @article{b, title = {Emergence of fast agreement in an overhearing population: The case of the naming game}, author = {Suman Kalyan Maity and Animesh Mukherjee and Francesca Tria and Vittorio Loreto}, year = {2013}, date = {2013-01-01}, journal = {EUROPHYSICS LETTERS}, volume = {101}, abstract = {The naming game (NG) describes the agreement dynamics of a population of N agents interacting locally in pairs leading to the emergence of a shared vocabulary. This model has its relevance in the novel fields of semiotic dynamics and specifically to opinion formation and language evolution. The application of this model ranges from wireless sensor networks as spreading algorithms, leader election algorithms to user-based social tagging systems. In this paper, we introduce the concept of overhearing (i.e., at every time step of the game, a random set of N-delta individuals are chosen from the population who overhear the transmitted word from the speaker and accordingly reshape their inventories). When delta = 0 one recovers the behavior of the original NG. As one increases delta, the population of agents reaches a faster agreement with a significantly low-memory requirement. The convergence time to reach global consensus scales as log N as delta approaches 1. Copyright (C) EPLA, 2013}, keywords = {language_dynamics, loreto, mukherjee, tria}, pubstate = {published}, tppubtype = {article} } The naming game (NG) describes the agreement dynamics of a population of N agents interacting locally in pairs leading to the emergence of a shared vocabulary. This model has its relevance in the novel fields of semiotic dynamics and specifically to opinion formation and language evolution. The application of this model ranges from wireless sensor networks as spreading algorithms, leader election algorithms to user-based social tagging systems. In this paper, we introduce the concept of overhearing (i.e., at every time step of the game, a random set of N-delta individuals are chosen from the population who overhear the transmitted word from the speaker and accordingly reshape their inventories). When delta = 0 one recovers the behavior of the original NG. As one increases delta, the population of agents reaches a faster agreement with a significantly low-memory requirement. The convergence time to reach global consensus scales as log N as delta approaches 1. Copyright (C) EPLA, 2013 |
Sirbu, Alina; Loreto, Vittorio; Servedio, Vito Domenico Pietro; Tria, Francesca Opinion Dynamics with Disagreement and Modulated Information Journal Article JOURNAL OF STATISTICAL PHYSICS, 151 , pp. 218–237, 2013. Abstract | BibTeX | Tags: loreto, opinion_dynamics, servedio, sirbu, tria @article{b, title = {Opinion Dynamics with Disagreement and Modulated Information}, author = {Alina Sirbu and Vittorio Loreto and Vito Domenico Pietro Servedio and Francesca Tria}, year = {2013}, date = {2013-01-01}, journal = {JOURNAL OF STATISTICAL PHYSICS}, volume = {151}, pages = {218--237}, abstract = {Opinion dynamics concerns social processes through which populations or groups of individuals agree or disagree on specific issues. As such, modelling opinion dynamics represents an important research area that has been progressively acquiring relevance in many different domains. Existing approaches have mostly represented opinions through discrete binary or continuous variables by exploring a whole panoply of cases: e.g. independence, noise, external effects, multiple issues. In most of these cases the crucial ingredient is an attractive dynamics through which similar or similar enough agents get closer. Only rarely the possibility of explicit disagreement has been taken into account (i.e., the possibility for a repulsive interaction among individuals' opinions), and mostly for discrete or 1-dimensional opinions, through the introduction of additional model parameters. Here we introduce a new model of opinion formation, which focuses on the interplay between the possibility of explicit disagreement, modulated in a self-consistent way by the existing opinions' overlaps between the interacting individuals, and the effect of external information on the system. Opinions are modelled as a vector of continuous variables related to multiple possible choices for an issue. Information can be modulated to account for promoting multiple possible choices. Numerical results show that extreme information results in segregation and has a limited effect on the population, while milder messages have better success and a cohesion effect. Additionally, the initial condition plays an important role, with the population forming one or multiple clusters based on the initial average similarity between individuals, with a transition point depending on the number of opinion choices.}, keywords = {loreto, opinion_dynamics, servedio, sirbu, tria}, pubstate = {published}, tppubtype = {article} } Opinion dynamics concerns social processes through which populations or groups of individuals agree or disagree on specific issues. As such, modelling opinion dynamics represents an important research area that has been progressively acquiring relevance in many different domains. Existing approaches have mostly represented opinions through discrete binary or continuous variables by exploring a whole panoply of cases: e.g. independence, noise, external effects, multiple issues. In most of these cases the crucial ingredient is an attractive dynamics through which similar or similar enough agents get closer. Only rarely the possibility of explicit disagreement has been taken into account (i.e., the possibility for a repulsive interaction among individuals' opinions), and mostly for discrete or 1-dimensional opinions, through the introduction of additional model parameters. Here we introduce a new model of opinion formation, which focuses on the interplay between the possibility of explicit disagreement, modulated in a self-consistent way by the existing opinions' overlaps between the interacting individuals, and the effect of external information on the system. Opinions are modelled as a vector of continuous variables related to multiple possible choices for an issue. Information can be modulated to account for promoting multiple possible choices. Numerical results show that extreme information results in segregation and has a limited effect on the population, while milder messages have better success and a cohesion effect. Additionally, the initial condition plays an important role, with the population forming one or multiple clusters based on the initial average similarity between individuals, with a transition point depending on the number of opinion choices. |
Loreto, Vittorio; Tria, Francesca Consensus in language dynamics: naming, categorizing and blending Incollection Shi, Feng; (Eds.), Gang Peng (Ed.): Festschrift in honor of Prof. William S-Y. Wang's 80th birthday, 2013. BibTeX | Tags: language_dynamics, loreto, tria @incollection{b_111, title = {Consensus in language dynamics: naming, categorizing and blending}, author = {Vittorio Loreto and Francesca Tria}, editor = {Feng Shi and Gang Peng (Eds.)}, year = {2013}, date = {2013-01-01}, booktitle = {Festschrift in honor of Prof. William S-Y. Wang's 80th birthday}, keywords = {language_dynamics, loreto, tria}, pubstate = {published}, tppubtype = {incollection} } |
2012 |
Miguel, Maxi San; Johnson, Jeffrey H; Kertesz, Janosz; Kaski, Kimmo; Diaz-Guilera, Albert; Mackay, Robert S; Loreto, Vittorio; Erdi, Peter; Helbing, Dirk Challenges in complex systems science Journal Article THE EUROPEAN PHYSICAL JOURNAL. SPECIAL TOPICS, 214 , pp. 245–271, 2012. Abstract | BibTeX | Tags: complex_systems, diaz-guilera, Erdi, helbing, johnson, kaski, kertesz, loreto, mackay, san miguel, social_dynamics @article{b, title = {Challenges in complex systems science}, author = {Maxi San Miguel and Jeffrey H. Johnson and Janosz Kertesz and Kimmo Kaski and Albert Diaz-Guilera and Robert S. Mackay and Vittorio Loreto and Peter Erdi and Dirk Helbing}, year = {2012}, date = {2012-01-01}, journal = {THE EUROPEAN PHYSICAL JOURNAL. SPECIAL TOPICS}, volume = {214}, pages = {245--271}, publisher = {SPRINGER HEIDELBERG}, abstract = {FuturICT foundations are social science, complex systems science, and ICT. The main concerns and challenges in the science of complex systems in the context of FuturICT are laid out in this paper with special emphasis on the Complex Systems route to Social Sciences. This include complex systems having: many heterogeneous interacting parts; multiple scales; complicated transition laws; unexpected or unpredicted emergence; sensitive dependence on initial conditions; path-dependent dynamics; networked hierarchical connectivities; interaction of autonomous agents; self-organisation; non-equilibrium dynamics; combinatorial explosion; adaptivity to changing environments; co-evolving subsystems; ill-defined boundaries; and multilevel dynamics. In this context, science is seen as the process of abstracting the dynamics of systems from data. This presents many challenges including: data gathering by large-scale experiment, participatory sensing and social computation, managing huge distributed dynamic and heterogeneous databases; moving from data to dynamical models, going beyond correlations to cause-effect relationships, understanding the relationship between simple and comprehensive models with appropriate choices of variables, ensemble modeling and data assimilation, modeling systems of systems of systems with many levels between micro and macro; and formulating new approaches to prediction, forecasting, and risk, especially in systems that can reflect on and change their behaviour in response to predictions, and systems whose apparently predictable behaviour is disrupted by apparently unpredictable rare or extreme events. These challenges are part of the FuturICT agenda.}, keywords = {complex_systems, diaz-guilera, Erdi, helbing, johnson, kaski, kertesz, loreto, mackay, san miguel, social_dynamics}, pubstate = {published}, tppubtype = {article} } FuturICT foundations are social science, complex systems science, and ICT. The main concerns and challenges in the science of complex systems in the context of FuturICT are laid out in this paper with special emphasis on the Complex Systems route to Social Sciences. This include complex systems having: many heterogeneous interacting parts; multiple scales; complicated transition laws; unexpected or unpredicted emergence; sensitive dependence on initial conditions; path-dependent dynamics; networked hierarchical connectivities; interaction of autonomous agents; self-organisation; non-equilibrium dynamics; combinatorial explosion; adaptivity to changing environments; co-evolving subsystems; ill-defined boundaries; and multilevel dynamics. In this context, science is seen as the process of abstracting the dynamics of systems from data. This presents many challenges including: data gathering by large-scale experiment, participatory sensing and social computation, managing huge distributed dynamic and heterogeneous databases; moving from data to dynamical models, going beyond correlations to cause-effect relationships, understanding the relationship between simple and comprehensive models with appropriate choices of variables, ensemble modeling and data assimilation, modeling systems of systems of systems with many levels between micro and macro; and formulating new approaches to prediction, forecasting, and risk, especially in systems that can reflect on and change their behaviour in response to predictions, and systems whose apparently predictable behaviour is disrupted by apparently unpredictable rare or extreme events. These challenges are part of the FuturICT agenda. |
Gravino, Pietro; Servedio, Vito D P; Barrat, Alain; Loreto, Vittorio Complex structures and semantics in free word association Journal Article ADVANCES IN COMPLEX SYSTEM, 15 , pp. 1250054–1250075, 2012. Abstract | Links | BibTeX | Tags: barrat, complex_networks, gravino, language_dynamics, loreto, semantic_networks, servedio, wordnet, word_association @article{b, title = {Complex structures and semantics in free word association}, author = {Pietro Gravino and Vito D.P. Servedio and Alain Barrat and Vittorio Loreto}, url = {http://www.worldscinet.com/acs/15/1503n04/S0219525912500543.html http://www.scopus.com/inward/record.url?eid=2-s2.0-84861899272&partnerID=65&md5=4d6ecfe66508c0a3cf8bba8dae67c997 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000304607400014&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a}, year = {2012}, date = {2012-01-01}, journal = {ADVANCES IN COMPLEX SYSTEM}, volume = {15}, pages = {1250054--1250075}, publisher = {WORLD SCIENTIFIC PUBL CO PTE LTD}, abstract = {We investigate the directed and weighted complex network of free word associations in which players write a word in response to another word given as input. We analyze in details two large datasets resulting from two very different experiments: On the one hand the massive multiplayer web-based Word Association Game known as Human Brain Cloud, and on the other hand the South Florida Free Association Norms experiment. In both cases, the networks of associations exhibit quite robust properties like the small world property, a slight assortativity and a strong asymmetry between in-degree and out-degree distributions. A particularly interesting result concerns the existence of a characteristic scale for the word association process, arguably related to specific conceptual contexts for each word. After mapping, the Human Brain Cloud network onto the WordNet semantics network, we point out the basic cognitive mechanisms underlying word associations when they are represented as paths in an underlying semantic network. We derive in particular an expression describing the growth of the HBC graph and we highlight the existence of a characteristic scale for the word association process.}, keywords = {barrat, complex_networks, gravino, language_dynamics, loreto, semantic_networks, servedio, wordnet, word_association}, pubstate = {published}, tppubtype = {article} } We investigate the directed and weighted complex network of free word associations in which players write a word in response to another word given as input. We analyze in details two large datasets resulting from two very different experiments: On the one hand the massive multiplayer web-based Word Association Game known as Human Brain Cloud, and on the other hand the South Florida Free Association Norms experiment. In both cases, the networks of associations exhibit quite robust properties like the small world property, a slight assortativity and a strong asymmetry between in-degree and out-degree distributions. A particularly interesting result concerns the existence of a characteristic scale for the word association process, arguably related to specific conceptual contexts for each word. After mapping, the Human Brain Cloud network onto the WordNet semantics network, we point out the basic cognitive mechanisms underlying word associations when they are represented as paths in an underlying semantic network. We derive in particular an expression describing the growth of the HBC graph and we highlight the existence of a characteristic scale for the word association process. |
Gong, Tao; Baronchelli, Andrea; Puglisi, Andrea; Loreto, Vittorio Exploring the roles of complex networks in linguistic categorization Journal Article ARTIFICIAL LIFE, 18 (1) , pp. 107–121, 2012. Abstract | Links | BibTeX | Tags: baronchelli, gong, language_dynamics, loreto, puglisi @article{b, title = {Exploring the roles of complex networks in linguistic categorization}, author = {Tao Gong and Andrea Baronchelli and Andrea Puglisi and Vittorio Loreto}, url = {http://www.mitpressjournals.org/doi/abs/10.1162/artl_a_00051 http://www.scopus.com/inward/record.url?eid=2-s2.0-84455212316&partnerID=65&md5=758e5307761080b1252443baf9d08abf http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000298413600005&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a http://socialdynamics.it/vittorioloreto/PAPERS/2012/Gongetal(2012)-ALife-CatGameNetwork.pdf}, year = {2012}, date = {2012-01-01}, journal = {ARTIFICIAL LIFE}, volume = {18 (1)}, pages = {107--121}, publisher = {MIT PRESS, 55 HAYWARD STREET, CAMBRIDGE, MA 02142 USA}, abstract = {This article adopts the category game model, which simulates the origins and evolution of linguistic categories in a group of artificial agents, to evaluate the effect of social structure on linguistic categorization. Based on the simulation results in a number of typical networks, we examine the isolating and collective effects of some structural features, including average degree, shortcuts, and level of centrality, on the categorization process. This study extends the previous simulations mainly on lexical evolution, and illustrates a general framework to systematically explore the effect of social structure on language evolution.}, keywords = {baronchelli, gong, language_dynamics, loreto, puglisi}, pubstate = {published}, tppubtype = {article} } This article adopts the category game model, which simulates the origins and evolution of linguistic categories in a group of artificial agents, to evaluate the effect of social structure on linguistic categorization. Based on the simulation results in a number of typical networks, we examine the isolating and collective effects of some structural features, including average degree, shortcuts, and level of centrality, on the categorization process. This study extends the previous simulations mainly on lexical evolution, and illustrates a general framework to systematically explore the effect of social structure on language evolution.
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Baronchelli, Andrea; Loreto, Vittorio; Tria, Francesca Language Dynamics Journal Article ADVANCES IN COMPLEX SYSTEM, 15 , pp. 1203002–12030011, 2012. Abstract | Links | BibTeX | Tags: baronchelli, language_dynamics, loreto, tria @article{b, title = {Language Dynamics}, author = {Andrea Baronchelli and Vittorio Loreto and Francesca Tria}, url = {http://www.worldscinet.com/acs/15/1503n04/S0219525912030026.html http://socialdynamics.it/vittorioloreto/PAPERS/2012/S0219525912030026.pdf}, year = {2012}, date = {2012-01-01}, journal = {ADVANCES IN COMPLEX SYSTEM}, volume = {15}, pages = {1203002--12030011}, publisher = {WORLD SCIENTIFIC PUBL CO PTE LTD}, abstract = {Thirty authors of different disciplines, ranging from cognitive science and linguistics to mathematics and physics, address the topic of language origin and evolution. Language dynamics is investigated through an interdisciplinary effort, involving field and synthetic experiments, modelling and comparison of the theoretical predictions with empirical data. The result consists in new insights that significantly contribute to the ongoing debate on the origin and the evolution of language. In this Topical Issue the state of the art of this novel and fertile approach is reported by major experts of the field.}, keywords = {baronchelli, language_dynamics, loreto, tria}, pubstate = {published}, tppubtype = {article} } Thirty authors of different disciplines, ranging from cognitive science and linguistics to mathematics and physics, address the topic of language origin and evolution. Language dynamics is investigated through an interdisciplinary effort, involving field and synthetic experiments, modelling and comparison of the theoretical predictions with empirical data. The result consists in new insights that significantly contribute to the ongoing debate on the origin and the evolution of language. In this Topical Issue the state of the art of this novel and fertile approach is reported by major experts of the field. |
Conte, Rosaria; Gilbert, Nigel; Bonelli, Giulia; Cioffi-Revilla, Claudio; Deffuant, Guillaume; Kertesz, Janosz; Loreto, Vittorio; Moat, Susy; Nadal, Jean-Pierre; Sanchez, Ancho; Nowak, Andrzej; Flache, Andreas; Miguel, Maxi San; Helbing, Dirk Manifesto of computational social science Journal Article THE EUROPEAN PHYSICAL JOURNAL. SPECIAL TOPICS, 214 , pp. 325–346, 2012. Abstract | BibTeX | Tags: Bonelli, cioffi-revilla, conte, deffuant, flache, Gilbert, helbing, kertesz, loreto, moat, nadal, nowak, san miguel, sanchez, social_dynamics @article{b, title = {Manifesto of computational social science}, author = {Rosaria Conte and Nigel Gilbert and Giulia Bonelli and Claudio Cioffi-Revilla and Guillaume Deffuant and Janosz Kertesz and Vittorio Loreto and Susy Moat and Jean-Pierre Nadal and Ancho Sanchez and Andrzej Nowak and Andreas Flache and Maxi San Miguel and Dirk Helbing}, year = {2012}, date = {2012-01-01}, journal = {THE EUROPEAN PHYSICAL JOURNAL. SPECIAL TOPICS}, volume = {214}, pages = {325--346}, abstract = {The increasing integration of technology into our lives has created unprecedented volumes of data on society’s everyday behaviour. Such data opens up exciting new opportunities to work towards a quantitative understanding of our complex social systems, within the realms of a new discipline known as Computational Social Science. Against a background of financial crises, riots and international epidemics, the urgent need for a greater comprehension of the complexity of our interconnected global society and an ability to apply such insights in policy decisions is clear. This manifesto outlines the objectives of this new scientific direction, considering the challenges involved in it, and the extensive impact on science, technology and society that the success of this endeavour is likely to bring about.}, keywords = {Bonelli, cioffi-revilla, conte, deffuant, flache, Gilbert, helbing, kertesz, loreto, moat, nadal, nowak, san miguel, sanchez, social_dynamics}, pubstate = {published}, tppubtype = {article} } The increasing integration of technology into our lives has created unprecedented volumes of data on society’s everyday behaviour. Such data opens up exciting new opportunities to work towards a quantitative understanding of our complex social systems, within the realms of a new discipline known as Computational Social Science. Against a background of financial crises, riots and international epidemics, the urgent need for a greater comprehension of the complexity of our interconnected global society and an ability to apply such insights in policy decisions is clear. This manifesto outlines the objectives of this new scientific direction, considering the challenges involved in it, and the extensive impact on science, technology and society that the success of this endeavour is likely to bring about. |
Tria, Francesca; Galantucci, Bruno; Loreto, Vittorio Naming a structured world: a cultural route to duality of patterning Journal Article PLOS ONE, pp. e37744-1–e37744-8, 2012. Abstract | Links | BibTeX | Tags: galantuccci, language_dynamics, loreto, tria @article{b, title = {Naming a structured world: a cultural route to duality of patterning}, author = {Francesca Tria and Bruno Galantucci and Vittorio Loreto}, url = {http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0037744 http://www.scopus.com/inward/record.url?eid=2-s2.0-84862532680&partnerID=65&md5=596aaa8cb591f6d2d7e2a31bcdf3213e http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000305652700006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a http://socialdynamics.it/vittorioloreto/PAPERS/2012/journal.pone.0037744.pdf}, year = {2012}, date = {2012-01-01}, journal = {PLOS ONE}, pages = {e37744-1--e37744-8}, abstract = {The lexicons of human languages organize their units at two distinct levels. At a first combinatorial level, meaningless forms (typically referred to as phonemes) are combined into meaningful units (typically referred to as morphemes). Thanks to this, many morphemes can be obtained by relatively simple combinations of a small number of phonemes. At a second compositional level of the lexicon, morphemes are composed into larger lexical units, the meaning of which is related to the individual meanings of the composing morphemes. This duality of patterning is not a necessity for lexicons and the question remains wide open regarding how a population of individuals is able to bootstrap such a structure and the evolutionary advantages of its emergence. Here we address this question in the framework of a multi-agents model, where a population of individuals plays simple naming games in a conceptual environment modeled as a graph. We demonstrate that errors in communication as well as a blending repair strategy, which crucially exploits a shared conceptual representation of the environment, are sufficient conditions for the emergence of duality of patterning, that can thus be explained in a pure cultural way. Compositional lexicons turn out to be faster to lead to successful communication than purely combinatorial lexicons, suggesting that meaning played a crucial role in the evolution of language.}, keywords = {galantuccci, language_dynamics, loreto, tria}, pubstate = {published}, tppubtype = {article} } The lexicons of human languages organize their units at two distinct levels. At a first combinatorial level, meaningless forms (typically referred to as phonemes) are combined into meaningful units (typically referred to as morphemes). Thanks to this, many morphemes can be obtained by relatively simple combinations of a small number of phonemes. At a second compositional level of the lexicon, morphemes are composed into larger lexical units, the meaning of which is related to the individual meanings of the composing morphemes. This duality of patterning is not a necessity for lexicons and the question remains wide open regarding how a population of individuals is able to bootstrap such a structure and the evolutionary advantages of its emergence. Here we address this question in the framework of a multi-agents model, where a population of individuals plays simple naming games in a conceptual environment modeled as a graph. We demonstrate that errors in communication as well as a blending repair strategy, which crucially exploits a shared conceptual representation of the environment, are sufficient conditions for the emergence of duality of patterning, that can thus be explained in a pure cultural way. Compositional lexicons turn out to be faster to lead to successful communication than purely combinatorial lexicons, suggesting that meaning played a crucial role in the evolution of language.
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Loreto, Vittorio; Mukherjee, Animesh; Tria, Francesca On the origin of the hierarchy of color names Journal Article PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA (PNAS), 2012. Abstract | Links | BibTeX | Tags: language_dynamics, loreto, mukherjee, tria @article{b, title = {On the origin of the hierarchy of color names}, author = {Vittorio Loreto and Animesh Mukherjee and Francesca Tria}, url = {http://www.pnas.org/content/early/2012/04/09/1113347109.abstract http://www.scopus.com/inward/record.url?eid=2-s2.0-84860819374&partnerID=65&md5=d7b06adcaee23e02cd4e3f3eeb6be15c http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000303602100019&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a http://socialdynamics.it/vittorioloreto/PAPERS/2012/PNAS-2012-Loreto-1113347109.pdf}, year = {2012}, date = {2012-01-01}, journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA (PNAS)}, abstract = {One of the fundamental problems in cognitive science is how humans categorize the visible color spectrum. The empirical evidence of the existence of universal or recurrent patterns in color naming across cultures is paralleled by the observation that color names begin to be used by individual cultures in a relatively fixed order. The origin of this hierarchy is largely unexplained. Here we resort to multiagent simulations, where a population of individuals, subject to a simple perceptual constraint shared by all humans, namely the human Just Noticeable Difference, categorizes and names colors through a purely cultural negotiation in the form of language games. We found that the time needed for a population to reach consensus on a color name depends on the region of the visible color spectrum. If color spectrum regions are ranked according to this criterion, a hierarchy with [red, (magenta)-red], [violet], [green/yellow], [blue], [orange], and [cyan], appearing in this order, is recovered, featuring an excellent quantitative agreement with the empirical observations of the WCS. Our results demonstrate a clear possible route to the emergence of hierarchical color categories, confirming that the theoretical modeling in this area has now attained the required maturity to make significant contributions to the ongoing debates concerning language universals.}, keywords = {language_dynamics, loreto, mukherjee, tria}, pubstate = {published}, tppubtype = {article} } One of the fundamental problems in cognitive science is how humans categorize the visible color spectrum. The empirical evidence of the existence of universal or recurrent patterns in color naming across cultures is paralleled by the observation that color names begin to be used by individual cultures in a relatively fixed order. The origin of this hierarchy is largely unexplained. Here we resort to multiagent simulations, where a population of individuals, subject to a simple perceptual constraint shared by all humans, namely the human Just Noticeable Difference, categorizes and names colors through a purely cultural negotiation in the form of language games. We found that the time needed for a population to reach consensus on a color name depends on the region of the visible color spectrum. If color spectrum regions are ranked according to this criterion, a hierarchy with [red, (magenta)-red], [violet], [green/yellow], [blue], [orange], and [cyan], appearing in this order, is recovered, featuring an excellent quantitative agreement with the empirical observations of the WCS. Our results demonstrate a clear possible route to the emergence of hierarchical color categories, confirming that the theoretical modeling in this area has now attained the required maturity to make significant contributions to the ongoing debates concerning language universals.
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Pompei, Simone; Loreto, Vittorio; Tria, Francesca Phylogenetic Properties of RNA Viruses Journal Article PLOS ONE, 7 , pp. e44849-1–e44849-10, 2012. Abstract | Links | BibTeX | Tags: evolutionary_dynamics, loreto, phylogeny, pompei, tria @article{b, title = {Phylogenetic Properties of RNA Viruses}, author = {Simone Pompei and Vittorio Loreto and Francesca Tria}, url = {http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0044849}, year = {2012}, date = {2012-01-01}, journal = {PLOS ONE}, volume = {7}, pages = {e44849-1--e44849-10}, abstract = {A new word, phylodynamics, was coined to emphasize the interconnection between phylogenetic properties, as observed for instance in a phylogenetic tree, and the epidemic dynamics of viruses, where selection, mediated by the host immune response, and transmission play a crucial role. The challenges faced when investigating the evolution of RNA viruses call for a virtuous loop of data collection, data analysis and modeling. This already resulted both in the collection of massive sequences databases and in the formulation of hypotheses on the main mechanisms driving qualitative differences observed in the (reconstructed) evolutionary patterns of different RNA viruses. Qualitatively, it has been observed that selection driven by the host immune response induces an uneven survival ability among co-existing strains. As a consequence, the imbalance level of the phylogenetic tree is manifestly more pronounced if compared to the case when the interaction with the host immune system does not play a central role in the evolutive dynamics. While many imbalance metrics have been introduced, reliable methods to discriminate in a quantitative way different level of imbalance are still lacking. In our work, we reconstruct and analyze the phylogenetic trees of six RNA viruses, with a special emphasis on the human Influenza A virus, due to its relevance for vaccine preparation as well as for the theoretical challenges it poses due to its peculiar evolutionary dynamics. We focus in particular on topological properties. We point out the limitation featured by standard imbalance metrics, and we introduce a new methodology with which we assign the correct imbalance level of the phylogenetic trees, in agreement with the phylodynamics of the viruses. Our thorough quantitative analysis allows for a deeper understanding of the evolutionary dynamics of the considered RNA viruses, which is crucial in order to provide a valuable framework for a quantitative assessment of theoretical predictions.}, keywords = {evolutionary_dynamics, loreto, phylogeny, pompei, tria}, pubstate = {published}, tppubtype = {article} } A new word, phylodynamics, was coined to emphasize the interconnection between phylogenetic properties, as observed for instance in a phylogenetic tree, and the epidemic dynamics of viruses, where selection, mediated by the host immune response, and transmission play a crucial role. The challenges faced when investigating the evolution of RNA viruses call for a virtuous loop of data collection, data analysis and modeling. This already resulted both in the collection of massive sequences databases and in the formulation of hypotheses on the main mechanisms driving qualitative differences observed in the (reconstructed) evolutionary patterns of different RNA viruses. Qualitatively, it has been observed that selection driven by the host immune response induces an uneven survival ability among co-existing strains. As a consequence, the imbalance level of the phylogenetic tree is manifestly more pronounced if compared to the case when the interaction with the host immune system does not play a central role in the evolutive dynamics. While many imbalance metrics have been introduced, reliable methods to discriminate in a quantitative way different level of imbalance are still lacking. In our work, we reconstruct and analyze the phylogenetic trees of six RNA viruses, with a special emphasis on the human Influenza A virus, due to its relevance for vaccine preparation as well as for the theoretical challenges it poses due to its peculiar evolutionary dynamics. We focus in particular on topological properties. We point out the limitation featured by standard imbalance metrics, and we introduce a new methodology with which we assign the correct imbalance level of the phylogenetic trees, in agreement with the phylodynamics of the viruses. Our thorough quantitative analysis allows for a deeper understanding of the evolutionary dynamics of the considered RNA viruses, which is crucial in order to provide a valuable framework for a quantitative assessment of theoretical predictions. |
Marchetti, Riccardo; Taloni, Alessandro; Caglioti, Emanuele; Loreto, Vittorio; Pietronero, Luciano Stationary Growth and Unique Invariant Harmonic Measure of Cylindrical Diffusion Limited Aggregation Journal Article PHYSICAL REVIEW LETTERS, 109 , 2012. Abstract | Links | BibTeX | Tags: caglioti, complex_systems, loreto, marchetti, pietronero, taloni @article{b, title = {Stationary Growth and Unique Invariant Harmonic Measure of Cylindrical Diffusion Limited Aggregation}, author = {Riccardo Marchetti and Alessandro Taloni and Emanuele Caglioti and Vittorio Loreto and Luciano Pietronero}, url = {http://prl.aps.org/}, year = {2012}, date = {2012-01-01}, journal = {PHYSICAL REVIEW LETTERS}, volume = {109}, publisher = {AMER PHYSICAL SOC}, abstract = {We prove that the harmonic measure is stationary, unique, and invariant on the interface of diffusion limited aggregation (DLA) growing on a cylinder surface. We provide a detailed theoretical analysis puzzling together multiscaling, multifractality, and conformal invariance, supported by extensive numerical simulations of clusters built using conformal mappings and on a lattice. The growth properties of the active and frozen zones are clearly elucidated. We show that the unique scaling exponent characterizing the stationary growth is the DLA fractal dimension.}, keywords = {caglioti, complex_systems, loreto, marchetti, pietronero, taloni}, pubstate = {published}, tppubtype = {article} } We prove that the harmonic measure is stationary, unique, and invariant on the interface of diffusion limited aggregation (DLA) growing on a cylinder surface. We provide a detailed theoretical analysis puzzling together multiscaling, multifractality, and conformal invariance, supported by extensive numerical simulations of clusters built using conformal mappings and on a lattice. The growth properties of the active and frozen zones are clearly elucidated. We show that the unique scaling exponent characterizing the stationary growth is the DLA fractal dimension. |
Mukherjee, Animesh; Loreto, Vittorio; Tria, Francesca Why are basic color names Journal Article ADVANCES IN COMPLEX SYSTEM, 15 , pp. 1150016–1150028, 2012. Abstract | Links | BibTeX | Tags: language_dynamics, loreto, mukherjee, tria @article{b, title = {Why are basic color names }, author = {Animesh Mukherjee and Vittorio Loreto and Francesca Tria}, url = {http://www.worldscinet.com/acs/15/1503n04/S0219525911003426.html http://www.scopus.com/inward/record.url?eid=2-s2.0-84861852212&partnerID=65&md5=5dc58383af9b9dc951b3821f9790de68 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000304607400003&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a http://socialdynamics.it/vittorioloreto/PAPERS/2012/S0219525911003426.pdf}, year = {2012}, date = {2012-01-01}, journal = {ADVANCES IN COMPLEX SYSTEM}, volume = {15}, pages = {1150016--1150028}, publisher = {WORLD SCIENTIFIC PUBL CO PTE LTD}, abstract = {It is widely known that color names across the world\'s languages tend to be organized into a neat hierarchy with a small set of \"basic names\" featuring in a comparatively fixed order across linguistic societies. However, to date, the basic names have only been defined through a set of linguistic principles. There is no statistical definition that quantitatively separates the basic names from the rest of the color words across languages. Here we present a rigorous statistical analysis of the World Color Survey database hosting color word information from 110 non-industrialized languages. The central result is that those names for which a population of individuals show a larger overall agreement across languages turn out to be the basic ones exactly reproducing the color name hierarchy and, thereby, providing, for the first time, an empirical definition of the basic color names.}, keywords = {language_dynamics, loreto, mukherjee, tria}, pubstate = {published}, tppubtype = {article} } It is widely known that color names across the world's languages tend to be organized into a neat hierarchy with a small set of "basic names" featuring in a comparatively fixed order across linguistic societies. However, to date, the basic names have only been defined through a set of linguistic principles. There is no statistical definition that quantitatively separates the basic names from the rest of the color words across languages. Here we present a rigorous statistical analysis of the World Color Survey database hosting color word information from 110 non-industrialized languages. The central result is that those names for which a population of individuals show a larger overall agreement across languages turn out to be the basic ones exactly reproducing the color name hierarchy and, thereby, providing, for the first time, an empirical definition of the basic color names. |
2011 |
Loreto, Vittorio; Tria, Francesca Linguistica in Silico Journal Article SISTEMI INTELLIGENTI, 2 , pp. 319–328, 2011. Links | BibTeX | Tags: language_dynamics, loreto, tria @article{b, title = {Linguistica in Silico}, author = {Vittorio Loreto and Francesca Tria}, url = {http://socialdynamics.it/vittorioloreto/PAPERS/2011/SISTEMI_INTELLIGENTI.pdf}, year = {2011}, date = {2011-01-01}, journal = {SISTEMI INTELLIGENTI}, volume = {2}, pages = {319--328}, keywords = {language_dynamics, loreto, tria}, pubstate = {published}, tppubtype = {article} } |
Tria, Francesca; Mukherjee, Animesh; Baronchelli, Andrea; Puglisi, Andrea; Loreto, Vittorio A fast no-rejection algorithm for the category game Journal Article JOURNAL OF COMPUTATIONAL SCIENCE, 2 , pp. 316–323, 2011. Abstract | Links | BibTeX | Tags: baronchelli, language_dynamics, loreto, mukherjee, puglisi, tria @article{b, title = {A fast no-rejection algorithm for the category game}, author = {Francesca Tria and Animesh Mukherjee and Andrea Baronchelli and Andrea Puglisi and Vittorio Loreto}, url = {http://www.sciencedirect.com/science/article/pii/S1877750311000883 http://www.scopus.com/inward/record.url?eid=2-s2.0-82455187963&partnerID=65&md5=2e81b85740b8a15a5b048389e9dbe573 http://socialdynamics.it/vittorioloreto/PAPERS/2011/JoCS_2011.pdf}, year = {2011}, date = {2011-01-01}, journal = {JOURNAL OF COMPUTATIONAL SCIENCE}, volume = {2}, pages = {316--323}, publisher = {Elsevier}, abstract = {The Category Game is a multi-agent model that accounts for the emergence of shared categorization patterns in a population of interacting individuals. In the framework of the model, linguistic categories appear as long lived consensus states that are constantly reshaped and re-negotiated by the communicating individuals. It is therefore crucial to investigate the long time behavior to gain a clear understanding of the dynamics. However, it turns out that the evolution of the emerging category system is so slow, already for small populations, that such an analysis has remained so far impossible. Here, we introduce a fast no-rejection algorithm for the Category Game that disentangles the physical simulation time from the CPU time, thus opening the way for thorough analysis of the model. We verify that the new algorithm is equivalent to the old one in terms of the emerging phenomenology and we quantify the CPU performances of the two algorithms, pointing out the neat advantages offered by the no-rejection one. This technical advance has already opened the way to new investigations of the model, thus helping to shed light on the fundamental issue of categorization.}, keywords = {baronchelli, language_dynamics, loreto, mukherjee, puglisi, tria}, pubstate = {published}, tppubtype = {article} } The Category Game is a multi-agent model that accounts for the emergence of shared categorization patterns in a population of interacting individuals. In the framework of the model, linguistic categories appear as long lived consensus states that are constantly reshaped and re-negotiated by the communicating individuals. It is therefore crucial to investigate the long time behavior to gain a clear understanding of the dynamics. However, it turns out that the evolution of the emerging category system is so slow, already for small populations, that such an analysis has remained so far impossible. Here, we introduce a fast no-rejection algorithm for the Category Game that disentangles the physical simulation time from the CPU time, thus opening the way for thorough analysis of the model. We verify that the new algorithm is equivalent to the old one in terms of the emerging phenomenology and we quantify the CPU performances of the two algorithms, pointing out the neat advantages offered by the no-rejection one. This technical advance has already opened the way to new investigations of the model, thus helping to shed light on the fundamental issue of categorization. |
Mukherjee, Animesh; Tria, Francesca; Baronchelli, Andrea; Puglisi, Andrea; Loreto, Vittorio Aging in language dynamics Journal Article PLOS ONE, 6(2) , 2011. Links | BibTeX | Tags: baronchelli, language_dynamics, loreto, mukherjee, puglisi, tria @article{b, title = {Aging in language dynamics}, author = {Animesh Mukherjee and Francesca Tria and Andrea Baronchelli and Andrea Puglisi and Vittorio Loreto}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-79951878510&partnerID=65&md5=cdc7034d1003aad153923fb5adf9ca72 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000287482300019&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a http://socialdynamics.it/vittorioloreto/PAPERS/2011/Mukherjee_PLS_ONE_2011.pdf}, year = {2011}, date = {2011-01-01}, journal = {PLOS ONE}, volume = {6(2)}, publisher = {San Francisco, CA : Public Library of Science}, keywords = {baronchelli, language_dynamics, loreto, mukherjee, puglisi, tria}, pubstate = {published}, tppubtype = {article} } |
Balzan, Riccardo; Dalton, Fergal; Loreto, Vittorio; Petri, Alberto; Pontuale, Giorgio Brownian motor in a granular medium Journal Article PHYSICAL REVIEW E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS, 83 , 2011. Abstract | Links | BibTeX | Tags: balzan, dalton, granular_media, loreto, petri @article{b, title = {Brownian motor in a granular medium}, author = {Riccardo Balzan and Fergal Dalton and Vittorio Loreto and Alberto Petri and Giorgio Pontuale}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-79961110600&partnerID=65&md5=02ae65b9fd908a65c1cf7a31749a58c0 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000288947100002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a}, year = {2011}, date = {2011-01-01}, journal = {PHYSICAL REVIEW E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS}, volume = {83}, publisher = {pubblicata da: AMERICAN PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, USA, MD, 20740-3844}, abstract = {In this work we experimentally study the behavior of a freely rotating asymmetric probe immersed in a vibrated granular medium. For a wide variety of vibration conditions the probe exhibits a steady rotation whose direction is constant with respect to the asymmetry. By changing the vibration amplitude and by filtering the noise in different frequency bands we show that the velocity of rotation depends not only on the RMS acceleration Γ, but also on the amount of energy provided to two separate frequency bands, which are revealed to be important for the dynamics of the granular medium: The first band governs the transfer of energy from the grains to the probe, and the second affects the dynamics by altering the viscosity of the vibro-fluidized material. © 2011 American Physical Society.}, keywords = {balzan, dalton, granular_media, loreto, petri}, pubstate = {published}, tppubtype = {article} } In this work we experimentally study the behavior of a freely rotating asymmetric probe immersed in a vibrated granular medium. For a wide variety of vibration conditions the probe exhibits a steady rotation whose direction is constant with respect to the asymmetry. By changing the vibration amplitude and by filtering the noise in different frequency bands we show that the velocity of rotation depends not only on the RMS acceleration Γ, but also on the amount of energy provided to two separate frequency bands, which are revealed to be important for the dynamics of the granular medium: The first band governs the transfer of energy from the grains to the probe, and the second affects the dynamics by altering the viscosity of the vibro-fluidized material. © 2011 American Physical Society. |
Loreto, Vittorio; Tria, Francesca In Silico Linguistics Comment on Journal Article PHYSICS OF LIFE REVIEWS, 8 , pp. 371–372, 2011. Links | BibTeX | Tags: language_dynamics, loreto, tria @article{b, title = {In Silico Linguistics Comment on }, author = {Vittorio Loreto and Francesca Tria}, url = {http://www.sciencedirect.com/science/article/pii/S1571064511001011 http://www.scopus.com/inward/record.url?eid=2-s2.0-84857142593&partnerID=65&md5=139dbe1d36036cc0f4829f8f5c394b08 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000298457400009&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a http://socialdynamics.it/vittorioloreto/PAPERS/2011/LORETO_PHYSICS_OF_LIFE_REVIEWS.pdf}, year = {2011}, date = {2011-01-01}, journal = {PHYSICS OF LIFE REVIEWS}, volume = {8}, pages = {371--372}, publisher = {ELSEVIER SCIENCE BV}, keywords = {language_dynamics, loreto, tria}, pubstate = {published}, tppubtype = {article} }
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Pompei, Simone; Tria, Francesca; Loreto, Vittorio On the accuracy of language trees Journal Article PLOS ONE, 6(6) , 2011. Links | BibTeX | Tags: evolutionary_dynamics, loreto, phylogeny, pompei, tria @article{b, title = {On the accuracy of language trees}, author = {Simone Pompei and Francesca Tria and Vittorio Loreto}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-79958041006&partnerID=65&md5=22335465a4b96cbddf4bbc9cefd7b7a8 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000291355500005&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a}, year = {2011}, date = {2011-01-01}, journal = {PLOS ONE}, volume = {6(6)}, publisher = {San Francisco, CA : Public Library of Science}, keywords = {evolutionary_dynamics, loreto, phylogeny, pompei, tria}, pubstate = {published}, tppubtype = {article} } |
Loreto, Vittorio; Baronchelli, Andrea; Mukherjee, Animesh; Puglisi, Andrea; Tria, Francesca Statistical physics of language dynamics Journal Article JOURNAL OF STATISTICAL MECHANICS: THEORY AND EXPERIMENT, P04006 , 2011. Links | BibTeX | Tags: baronchelli, language_dynamics, loreto, mukherjee, puglisi, tria @article{b, title = {Statistical physics of language dynamics}, author = {Vittorio Loreto and Andrea Baronchelli and Animesh Mukherjee and Andrea Puglisi and Francesca Tria}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-79955826233&partnerID=65&md5=01b4b20367082bee503a7ba5a2718b9d http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000289995100007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a http://socialdynamics.it/vittorioloreto/PAPERS/2011/LORETO_JSTAT_2011.pdf}, year = {2011}, date = {2011-01-01}, journal = {JOURNAL OF STATISTICAL MECHANICS: THEORY AND EXPERIMENT}, volume = {P04006}, publisher = {Bristol : IOP Publishing}, keywords = {baronchelli, language_dynamics, loreto, mukherjee, puglisi, tria}, pubstate = {published}, tppubtype = {article} } |
2010 |
Tria, Francesca; Caglioti, Emanuele; Loreto, Vittorio; Pagnani, Andrea A Stochastic Local Search Algorithm for Distance-Based Phylogeny Reconstruction Journal Article MOLECULAR BIOLOGY AND EVOLUTION, 27 (11) , pp. 2587–2595, 2010. Links | BibTeX | Tags: caglioti, evolutionary_dynamics, loreto, pagnani, phylogeny, tria @article{b, title = {A Stochastic Local Search Algorithm for Distance-Based Phylogeny Reconstruction}, author = {Francesca Tria and Emanuele Caglioti and Vittorio Loreto and Andrea Pagnani}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-77958142872&partnerID=65&md5=8bb15034042b6d808b9afb8819bb44d6 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000283118000015&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a}, year = {2010}, date = {2010-01-01}, journal = {MOLECULAR BIOLOGY AND EVOLUTION}, volume = {27 (11)}, pages = {2587--2595}, keywords = {caglioti, evolutionary_dynamics, loreto, pagnani, phylogeny, tria}, pubstate = {published}, tppubtype = {article} } |
Tria, Francesca; Caglioti, Emanuele; Loreto, Vittorio; Pagnani, Andrea A stochastic local search approach to language tree reconstruction Journal Article 27 , pp. 341–358, 2010. Links | BibTeX | Tags: caglioti, evolutionary_dynamics, loreto, pagnani, phylogeny, tria @article{b, title = {A stochastic local search approach to language tree reconstruction}, author = {Francesca Tria and Emanuele Caglioti and Vittorio Loreto and Andrea Pagnani}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-77958505543&partnerID=65&md5=2a15ef158e89c0e12ba7d0efb7201de5 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000283796800009&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a}, year = {2010}, date = {2010-01-01}, volume = {27}, pages = {341--358}, keywords = {caglioti, evolutionary_dynamics, loreto, pagnani, phylogeny, tria}, pubstate = {published}, tppubtype = {article} } |
Caglioti, Emanuele; Loreto, Vittorio; Pompei, Simone; Tria, Francesca Distance-based Phylogenetic algorithms: new insights and applications Journal Article MATHEMATICAL MODELS AND METHODS IN APPLIED SCIENCES, 20 , pp. 1511–1532, 2010. Links | BibTeX | Tags: caglioti, evolutionary_dynamics, loreto, phylogeny, pompei, tria @article{b, title = {Distance-based Phylogenetic algorithms: new insights and applications}, author = {Emanuele Caglioti and Vittorio Loreto and Simone Pompei and Francesca Tria}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-77957171910&partnerID=65&md5=41f74dd5dff0e500c1061a8d02fcd6c8 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000282218000006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a}, year = {2010}, date = {2010-01-01}, journal = {MATHEMATICAL MODELS AND METHODS IN APPLIED SCIENCES}, volume = {20}, pages = {1511--1532}, publisher = {World Scientific Publishing Company:PO Box 128, Farrer Road, Singapore 912805 Singapore:011 65 6 4665775, EMAIL: journal@wspc.com.sg, INTERNET: http://www.wspc.com.sg, http://www.worldscinet.com, Fax: 011 65 6 4677667}, keywords = {caglioti, evolutionary_dynamics, loreto, phylogeny, pompei, tria}, pubstate = {published}, tppubtype = {article} } |
Baronchelli, Andrea; Gong, Tao; Puglisi, Aandrea; Loreto, Vittorio Modeling the emergence of universality in color naming patterns Journal Article PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA (PNAS), 107 , pp. 2403–2407, 2010. Abstract | Links | BibTeX | Tags: baronchelli, gong, language_dynamics, loreto, puglisi @article{b, title = {Modeling the emergence of universality in color naming patterns}, author = {Andrea Baronchelli and Tao Gong and Aandrea Puglisi and Vittorio Loreto}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-77349119009&partnerID=65&md5=6cdcb665c28403d74f0a0437b8e4c0cf http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000274408100011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a http://socialdynamics.it/vittorioloreto/PAPERS/2010/Baronchelli_PNAS_2010.pdf}, year = {2010}, date = {2010-01-01}, journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA (PNAS)}, volume = {107}, pages = {2403--2407}, publisher = {NATL ACAD SCIENCES}, abstract = {The empirical evidence that human color categorization exhibits some universal patterns beyond superficial discrepancies across different cultures is a major breakthrough in cognitive science. As observed in the World Color Survey (WCS), indeed, any two groups of individuals develop quite different categorization patterns, but some universal properties can be identified by a statistical analysis over a large number of populations. Here, we reproduce the WCS in a numerical model in which different populations develop independently their own categorization systems by playing elementary language games. We find that a simple perceptual constraint shared by all humans, namely the human Just Noticeable Difference (JND), is sufficient to trigger the emergence of universal patterns that unconstrained cultural interaction fails to produce. We test the results of our experiment against real data by performing the same statistical analysis proposed to quantify the universal tendencies shown in the WCS [Kay P & Regier T. (2003) Proc. Natl. Acad. Sci. USA 100: 9085-9089], and obtain an excellent quantitative agreement. This work confirms that synthetic modeling has nowadays reached the maturity to contribute significantly to the ongoing debate in cognitive science.}, keywords = {baronchelli, gong, language_dynamics, loreto, puglisi}, pubstate = {published}, tppubtype = {article} } The empirical evidence that human color categorization exhibits some universal patterns beyond superficial discrepancies across different cultures is a major breakthrough in cognitive science. As observed in the World Color Survey (WCS), indeed, any two groups of individuals develop quite different categorization patterns, but some universal properties can be identified by a statistical analysis over a large number of populations. Here, we reproduce the WCS in a numerical model in which different populations develop independently their own categorization systems by playing elementary language games. We find that a simple perceptual constraint shared by all humans, namely the human Just Noticeable Difference (JND), is sufficient to trigger the emergence of universal patterns that unconstrained cultural interaction fails to produce. We test the results of our experiment against real data by performing the same statistical analysis proposed to quantify the universal tendencies shown in the WCS [Kay P & Regier T. (2003) Proc. Natl. Acad. Sci. USA 100: 9085-9089], and obtain an excellent quantitative agreement. This work confirms that synthetic modeling has nowadays reached the maturity to contribute significantly to the ongoing debate in cognitive science. |
2009 |
Cattuto, Ciro; Barrat, Alain; Baldassarri, Andrea; Schehr, Gregory; Loreto, Vittorio Collective dynamics of social annotation Journal Article PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA (PNAS), 106 , pp. 10511–10515, 2009. Links | BibTeX | Tags: baldassarri, barrat, cattuto, loreto, schehr, social_annotation, techno_social_systems @article{b, title = {Collective dynamics of social annotation}, author = {Ciro Cattuto and Alain Barrat and Andrea Baldassarri and Gregory Schehr and Vittorio Loreto}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-67649743814&partnerID=65&md5=b62adb16a4fd2991f30173cc832acb65 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000267564300024&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a}, year = {2009}, date = {2009-01-01}, journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA (PNAS)}, volume = {106}, pages = {10511--10515}, publisher = {National Academy of Sciences:2101 Constitution Avenue Northwest:Washington, DC 20418:(877)314-2253, (615)377-3322, EMAIL: subspnas@nas.edu, INTERNET: http://www.pnas.org, Fax: (615)377-0525}, keywords = {baldassarri, barrat, cattuto, loreto, schehr, social_annotation, techno_social_systems}, pubstate = {published}, tppubtype = {article} } |
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