Encrypted CDMA audio network

We present a secure LAN using sound as the physical layer for low speed applications. In particular, we show a real implementation of a point-to-point or point-to-multipoint secure acoustic network, having a short range, consuming a negligible amount of power, and requiring no specific hardware on mobile clients. The present acoustic network provides VPN-like private channels to multiple users sharing the same medium. It is based on Time-hopping CDMA, and makes use of an encrypted Bloom filter. An asymmetrical error-correction is used to supply data integrity, even in the presence of strong interference. Simulations and real experiments show its feasibility. We also provide some theoretical analysis on the principle of operation.Fil: Ortega, Alfredo A.. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Bettachini, Victor. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fierens, Pablo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Alvarez Hamelin, Jose Ignacio. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Deciphering the global organization of clustering in real complex networks

We uncover the global organization of clustering in real complex networks. To this end, we ask whether triangles in real networks organize as in maximally random graphs with given degree and clustering distributions, or as in maximally ordered graph models where triangles are forced into modules. The answer comes by way of exploring m-core landscapes, where the m-core is defined, akin to the k-core, as the maximal subgraph with edges participating in at least m triangles. This property defines a set of nested subgraphs that, contrarily to k-cores, is able to distinguish between hierarchical and modular architectures. We find that the clustering organization in real networks is neither completely random nor ordered although, surprisingly, it is more random than modular. This supports the idea that the structure of real networks may in fact be the outcome of self-organized processes based on local optimization rules, in contrast to global optimization principles.Fil: Colomer de Simón, Pol. Universidad de Barcelona; EspañaFil: Serrano, María de Los Angeles. Universidad de Barcelona; EspañaFil: Beiro, Mariano Gastón. Universidad de Buenos Aires. Facultad de Ingenieria. Departamento de Electronica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; ArgentinaFil: Alvarez Hamelin, Jose Ignacio. Universidad de Buenos Aires. Facultad de Ingenieria. Departamento de Electronica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; ArgentinaFil: Boguñá, Marián. Universidad de Barcelona; Españ

CDMA Time-hopping optical network with enhanced security

A method to provide cryptographically secure point-to-point and point-to-multipoint communication using an encrypted Bloom filter is implemented on a time-hopping CDMA optical fiber network. A novel Hammingweight minimization coding algorithm optimises the performance of the encrypted Bloom filter in terms of end-user bandwidth utilisation over previous proposals. The system has a total channel utilisation of up to 29% for 128 simultaneous users, up to 20 km apart, served by a single passive optical hub, or longer distances if served by an active hub.Fil: Ortega, A. A.. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Bettachini, Victor. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alvarez Hamelin, Jose Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Socioeconomic correlations and stratification in social-communication networks

The uneven distribution of wealth and individual economic capacities are among the main forces, which shape modern societies and arguably bias the emerging social structures. However, the study of correlations between the social network and economic status of individuals is difficult due to the lack of large-scale multimodal data disclosing both the social ties and economic indicators of the same population. Here, we close this gap through the analysis of coupled datasets recording the mobile phone communications and bank transaction history of one million anonymized individuals living in a Latin American country. We show that wealth and debt are unevenly distributed among people in agreement with the Pareto principle; the observed social structure is strongly stratified, with people being better connected to others of their own socioeconomic class rather than to others of different classes; the social network appears to have assortative socioeconomic correlations and tightly connected ‘rich clubs’; and that individuals from the same class live closer to each other but commute further if they are wealthier. These results are based on a representative, society-large population, and empirically demonstrate some long-lasting hypotheses on socioeconomic correlations, which potentially lay behind social segregation, and induce differences in human mobility.Fil: Leo, Yannick. Centre National de la Recherche Scientifique; Francia. Institut National de Recherche en Informatique et en Automatique; Francia. Université Claude Bernard Lyon 1; FranciaFil: Fleury, Eric. Université Claude Bernard Lyon 1; Francia. Centre National de la Recherche Scientifique; Francia. Institut National de Recherche en Informatique et en Automatique; FranciaFil: Alvarez Hamelin, Jose Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; ArgentinaFil: Sarraute, Carlos. Grandata Labs; ArgentinaFil: Karsai, Márton. Université Claude Bernard Lyon 1; Francia. Centre National de la Recherche Scientifique; Francia. Institut National de Recherche en Informatique et en Automatique; Franci

Study of the influence of the phylogenetic distance on the interaction network of mutualistic ecosystems

We investigate how the phylogenetic relationship between the species of each interacting guild in a mutualistic ecosystem influences its network of contacts. We develop a dynamical self organized model that reallocates contacts between mutualists, according to a contact preference rule (CPR) that takes into account phylogenetic distances. We conclude that a CPR that promotes phylogenetic proximity among the counterparts of the species of each guild leads to highly unrealistic contact patterns. We find that nestedness can instead be attributed to a general rule by which species tend to behave as generalists holding contacts with counterparts that already have a large number of contacts.Fil: Perazzo, Roberto P. J.. Instituto Tecnologico de Buenos Aires; ArgentinaFil: Hernández, Laura. Centre National de la Recherche Scientifique; FranciaFil: Ceva, Horacio. Comision Nacional de Energia Atomica; ArgentinaFil: Burgos, Enrique Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energia Atomica; ArgentinaFil: Alvarez Hamelin, Jose Ignacio. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin