Artículos con la etiqueta ‘física y sociedad’

Simulations suggest that social and natural sciences differ in their research strategies adapted to work for different knowledge landscapes

Por • 26 mar, 2014 • Category: Ambiente

Do different field of knowledge require different research strategies? A numerical model exploring different virtual knowledge landscapes, revealed different optimal search strategies. Trend following is maximized when the popularity of new discoveries determine the number of individuals researching it. This strategy works best when many researchers explore few large areas of knowledge. In contrast, individuals or small groups of researchers are better in discovering small bits of information in dispersed knowledge landscapes. The best technique for all situations simulated, is to adjust the number of researchers needed to explore a knowledge cluster according to the opportunities and the level of crowding in that cluster.

Universality in systems with group-outcome decision making

Por • 26 may, 2013 • Category: sociologia

Elections constitute a paradigm of decision making problems that have puzzled experts of different disciplines for decades. We study two decision making problems, where groups make decisions that only impact themselves as a group. In both studied cases, participation to local elections and the number of democratic representatives at different scales (from local to national), we observe a universal scaling with the constituency size. These results may be interpreted as constituencies having a hierarchical structure, where each group of N agents, at each level of the hierarchy, is divided in N^{1/3} subgroups. Following this interpretation, a phenomenological model of vote participation, where abstention is related to the perceived link of an agent to the rest of the constituency, reproduces quantitatively the observed data.

Evolutionary dynamics of group interactions on structured populations: A review

Por • 13 ene, 2013 • Category: sociologia

Interactions among living organisms, from bacteria colonies to human societies, are inherently more complex than interactions among particles and nonliving matter. Group interactions are a particularly important and widespread class, representative of which is the public goods game. In addition, methods of statistical physics have proven valuable for studying pattern formation, equilibrium selection, and self-organisation in evolutionary games. Here we review recent advances in the study of evolutionary dynamics of group interactions on structured populations, including lattices, complex networks and coevolutionary models. We also compare these results with those obtained on well-mixed populations. The review particularly highlights that the study of the dynamics of group interactions, like several other important equilibrium and non-equilibrium dynamical processes in biological, economical and social sciences, benefits from the synergy between statistical physics, network science and evolutionary game theory.

Joint Scaling Theory of Human Dynamics and Network Science

Por • 13 sep, 2012 • Category: Opinion

The increasing availability of large-scale data on human behavior has catalyzed simultaneous advances in network theory, capturing the scaling properties of the interactions between a large number of individuals, and human dynamics, quantifying the temporal characteristics of human activity patterns. These two areas remain disjoint, however, traditionally each pursuing as a separate modeling framework. Here we establish the first formal link between these two areas by showing that the exponents characterizing the degree and link weight distribution in social networks can be expressed in terms of the dynamical exponents characterizing human activity patterns. We test the validity of these theoretical predictions on datasets capturing various facets of human interactions, from mobile calls to tweets. We find evidence of a universal measure, that links networks and human dynamics, but whose value is independent of the means of communication, capturing a fundamental property of human activity.

Spreading scientific philosophies with instruments: the case of Atwood’s machine

Por • 17 abr, 2012 • Category: sociologia

We study how the paradigm of Newton’s science, based on the organization of scientific knowledge as a series of mathematical laws, was definitively accepted in science courses – in the last decades of the XVIII century, in England as well as in the Continent – by means of the «universal» dynamical machine invented by George Atwood in late 1770s just for this purpose. The spreading of such machine, occurred well before the appearance of Atwood’s treatise where he described the novel machine and the experiments to be performed with it, is a quite interesting historical case, which we consider in some detail. In particular, we focus on the «improvement» introduced by the Italian Giuseppe Saverio Poli and the subsequent «simplifications» of the machine, underlying the ongoing change of perspective after the definitive success of Newtonianism. The case studied here allows to recognize the relevant role played by a properly devised instrument in the acceptance of a new paradigm by non-erudite scholars, in addition to the traditional ways involving erudite scientists, and thus the complementary role of machine philosophy with respect to mathematical, philosophical or even physical reasoning.

Random walks on temporal networks

Por • 17 mar, 2012 • Category: sociologia

Many natural and artificial networks evolve in time. Nodes and connections appear and disappear at various timescales, and their dynamics has profound consequences for any processes in which they are involved. The first empirical analysis of the temporal patterns characterizing dynamic networks are still recent, so that many questions remain open. Here, we study how random walks, as paradigm of dynamical processes, unfold on temporally evolving networks. Furthermore, we introduce different randomizing strategies that allow us to single out the role of the different properties of the empirical networks. We show that the random walk exploration is slower on temporal networks than it is on the aggregate projected network, even when the time is properly rescaled. In particular, we point out that a fundamental role is played by the temporal correlations between consecutive contacts present in the data. Finally, we address the consequences of the intrinsically limited duration of many real world dynamical networks.

Quantum decision making by social agents

Por • 1 mar, 2012 • Category: sociologia

Decision making of agents who are members of a society is analyzed from the point of view of quantum decision theory. This generalizes the approach, developed earlier by the authors for separate individuals, to decision making under the influence of social interactions. The generalized approach not only avoids paradoxes, typical of classical decision making based on utility theory, but also explains the error-attenuation effects observed for the paradoxes occurring when decision makers, who are members of a society, consult with each other increasing in this way the available mutual information.

Culturomics meets random fractal theory: Insights into long-range correlations of social and natural phenomena over the past two centuries

Por • 24 feb, 2012 • Category: sociologia

Culturomics was recently introduced as the application of high-throughput data collection and analysis to the study of human culture. Here we make use of this data by investigating fluctuations in yearly usage frequencies of specific words that describe social and natural phenomena, as derived from books that were published over the course of the past two centuries. We show that the determination of the Hurst parameter by means of fractal analysis provides fundamental insights into the nature of long-range correlations contained in the culturomic trajectories, and by doing so, offers new interpretations as to what might be the main driving forces behind the examined phenomena. Quite remarkably, we find that social and natural phenomena are governed by fundamentally different processes. While natural phenomena have properties that are typical for processes with persistent long-range correlations, social phenomena are better described as nonstationary, on-off intermittent, or Levy walk processes.

Spatiotemporal features of human mobility

Por • 5 feb, 2012 • Category: sociologia

The individual movements of large numbers of people are important in many contexts, from urban planning to disease spreading. Datasets that capture human mobility are now available and many interesting features have been discovered, including the ultra-slow spatial growth of individual mobility. However, the detailed substructures and spatiotemporal flows of mobility-the sets and sequences of visited locations-have not been well studied. We show that individual mobility is dominated by small groups of frequently visited, dynamically close locations, forming primary «habitats» capturing typical daily activity, along with subsidiary habitats representing additional travel. These habitats do not correspond to typical contexts such as home or work. The temporal evolution of mobility within habitats, which constitutes most motion, is universal across habitats and exhibits scaling patterns both distinct from all previous observations and unpredicted by current models. The delay to enter subsidiary habitats is a primary factor in the spatiotemporal growth of human travel. Interestingly, habitats correlate with non-mobility dynamics such as communication activity, implying that habitats may influence processes such as information spreading and revealing new connections between human mobility and social networks.

The workings of the Maximum Entropy Principle in collective human behavior

Por • 27 ene, 2012 • Category: sociologia

We exhibit compelling evidence regarding how well does the MaxEnt principle describe the rank-distribution of city-populations via an exhaustive study of the 50 Spanish provinces (more than 8000 cities) in a time-window of 15 years (1996-2010). We show that the dynamics that governs the population-growth is the deciding factor that originates the observed distributions. The connection between dynamics and distributions is unravelled via MaxEnt.