La Geometria oculta d'Internet

Internet està provocant una revolució tecnològica només comparable amb el desenvolupament de l'electricitat a fi nals del segle ������. Contràriament al que es pot pensar, Internet no és un sistema planifi cat, sinó que evoluciona de manera autoorganitzada segons les seves pròpies lleis. Resulta fonamental, doncs, si en volem preveure l'evolució i prevenir possibles col·lapses del sistema, apropar-nos al seu estudi amb els ulls d'un cien�� fi c. En aquest sen�� t, el protocol més fonamental d'Internet, l'encarregat de redirigir els paquets d'informació, està pa�� nt una sobrecàrrega deguda al creixement desmesurat de la xarxa. En aquest ar�� cle presentem una alterna�� va basada en les propietats dels espais hiperbòlics que té el potencial de conver�� r-se en una alterna�� va viable al protocol actual

Competition between global and local online social networks

The overwhelming success of online social networks, the key actors in the Web 2.0 cosmos, has reshaped human interactions globally. To help understand the fundamental mechanisms which determine the fate of online social networks at the system level, we describe the digital world as a complex ecosystem of interacting networks. In this paper, we study the impact of heterogeneity in network fitnesses on the competition between an international network, such as Facebook, and local services. The higher fitness of international networks is induced by their ability to attract users from all over the world, which can then establish social interactions without the limitations of local networks. In other words, inter-country social ties lead to increased fitness of the international network. To study the competition between an international network and local ones, we construct a 1:1000 scale model of the digital world, consisting of the 80 countries with the most Internet users. Under certain conditions, this leads to the extinction of local networks; whereas under different conditions, local networks can persist and even dominate completely. In particular, our model suggests that, with the parameters that best reproduce the empirical overtake of Facebook, this overtake could have not taken place with a significant probabilit

La Geometria oculta d'Internet

Internet està provocant una revolució tecnològica només comparable amb el desenvolupament de l'electricitat a fi nals del segle ������. Contràriament al que es pot pensar, Internet no és un sistema planifi cat, sinó que evoluciona de manera autoorganitzada segons les seves pròpies lleis. Resulta fonamental, doncs, si en volem preveure l'evolució i prevenir possibles col·lapses del sistema, apropar-nos al seu estudi amb els ulls d'un cien�� fi c. En aquest sen�� t, el protocol més fonamental d'Internet, l'encarregat de redirigir els paquets d'informació, està pa�� nt una sobrecàrrega deguda al creixement desmesurat de la xarxa. En aquest ar�� cle presentem una alterna�� va basada en les propietats dels espais hiperbòlics que té el potencial de conver�� r-se en una alterna�� va viable al protocol actual

Digital ecology: coexistence and domination among interacting networks

The overwhelming success of Web 2.0, within which online social networks are key actors, has induced a paradigm shift in the nature of human interactions. The user-driven character of Web 2.0 services has allowed researchers to quantify large-scale social patterns for the first time. However, the mechanisms that determine the fate of networks at the system level are still poorly understood. For instance, the simultaneous existence of multiple digital services naturally raises questions concerning which conditions these services can coexist under. Analogously to the case of population dynamics, the digital world forms a complex ecosystem of interacting networks. The fitness of each network depends on its capacity to attract and maintain users' attention, which constitutes a limited resource. In this paper, we introduce an ecological theory of the digital world which exhibits stable coexistence of several networks as well as the dominance of an individual one, in contrast to the competitive exclusion principle. Interestingly, our theory also predicts that the most probable outcome is the coexistence of a moderate number of services, in agreement with empirical observations

Cosmological networks

Networks often represent systems that do not have a long history of study in traditional fields of physics; albeit, there are some notable exceptions, such as energy landscapes and quantum gravity. Here, we consider networks that naturally arise in cosmology. Nodes in these networks are stationary observers uniformly distributed in an expanding open Friedmann-Lemaitre-Robertson-Walker universe with any scale factor and two observers are connected if one can causally influence the other. We show that these networks are growing Lorentz-invariant graphs with power-law distributions of node degrees. These networks encode maximum information about the observable universe available to a given observer