Explorant els sistemes complexos

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Institut de Ciències de l'Educació projects 03/10/2018

L'UBICS col·laborarà en l'activitat organitzada per anomenada 'Explorant els sistemes complexos', que es durà a terme el 9 de novembre a la Facultat de Física, UB. El principal objectiu de l'activitat és fer arribar als docents de secundària de diferents matèries la ciència dels sistemes complexos.

Physics also wants to cure cancer

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Universitat de Barcelona papers 02/10/2018

A malignant tumor is characterized by its ability to spread around its surroundings. To do so, tumor cells stick to the surrounding tissue (mainly collagen) and use forces to propel. The journal Nature Physics published a study by a team led by Xavier Trepat, ICREA researcher at the Institute for Bioengineering of Catalonia (IBEC) and lecturer at the Department of Biomedicine University of Barcelona (UB), and Jaume Casademunt, professor of Physics at the UB and member of the University of Barcelona Institute of Complex Systems (UBICS), reveals the forces these tumor cells use to spread. The relation between these forces and the cell movement goes beyond current physical laws.


More info

Annual Report 2017 available

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albert products 31/07/2018

Annual Report 2017 available:

- PDF format

- ISSUU viewer

UBICS' Project : ‘Mapping Big Data Systems: embedding large complex networks in low-dimensional hidden metric spaces’ will be funded by Fundación BBVA

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qa projects 01/06/2018

Mapping Big Data Systems: embedding large complex networks in low-dimensional hidden metric spaces’

Investigador principal: M. Ángeles Serrano (Física de la Matèria Condensada / UBICS / ICREA, Universitat de Barcelona)

Membres de l'equip: Marián Boguñá Espinal (Universitat de Barcelona), Antoine Allard (Universitat de Barcelona), Michele Starnini (Universitat de Barcelona), Muhua Zheng (Universitat de Barcelona), Guillermo García Pérez (Universitat de Barcelona); Xavier Roderic Hoffmann Salvañá (Universitat de Barcelona); Elisenda Ortiz Castillo (Universitat de Barcelona)

Ajuda concedida per la fundació BBVA a un dels cinc equips d'investigació Científica en l'àrea de de Big Data, amb una dotació econòmica pel projecte de recerca de 100.000 euros

Congratulations to UBICS' member Konstantina Theofanoupoulou , she will be UB's represntative for 3MT from Grup Coïmbra and Fundació Catalana per a la Recerca i la Innovació (FCRi) Awards

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UBICS people 22/03/2018

Konstantina Theofanoupoulou serà la representant de la UB al 3MT del Grup Coïmbra i al premi de la FCRi

dijous, 22 març, 2018

La Universitat de Barcelona ja té guanyadora de la fase institucional pels concursos de tesis del Grup Coïmbra i de la Fundació Catalana per a la Recerca i la Innovació (FCRi). Konstantina Theofanopoulou, del programa de doctorat Ciència Cognitiva i Llenguatge, i membre de l'UBICS, va guanyar la final amb la presentació “Are modern humans self-domesticated” i serà la representant de la UB en ambdós concursos. Theofanopoulou va defensar davant del jurat la seva recerca que pretén explicar la sociabilitat humana partint de diferents proves que demostren una semblança amb les espècies domesticades en termes de comportament, en termes anatòmics, i en termes genètics.

A la final, que va contar amb les presentacions dels nou participants seleccionats entre els 25 que es van presentar, també es va premiar en segona posició a Rosa Diego Creixenti del programa de Nanociències amb “Making things smaller” i a Ana Martina Greco del programa de Cervell, Cognició i Conducta amb “A hidden reality”.

L’acte, que va ser presentat pel director de l’Escola de Doctorat, el doctor Francesc Xavier Roigé, va ser un èxit, tan per qualitat com per assistència. Theofanopoulou haurà de defensar la seva presentació a la final de la FCRi i entra a la fase europea de selecció del Grup Coïmbra; en cas de ser seleccionada participaria a la final que enguany es celebra a Salamanca i que uneix els tres millors oradors a nivell internacional.

A new technique allows researchers to create real system 'cartographic' maps at different scales: “Multiscale unfolding of real complex networks by geometric renormalization”

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UBICS projects 19/03/2018


A new technique allows researchers to create real system 'cartographic' maps at different scales

There is something in common in the following systems: the Internet, the world airport network, the human proteome, music, Darwin’s On the Origin of Species, the mailing system of a company, the human metabolic network and the brain of Drosophila fly. All of these are complex networks with similar properties. This was used by a team of the Institute of Complex Systems of the University of Barcelona (UBICS) to work on a technique that allows researchers to represent these systems geometrically at different scales as if they were “cartographic” maps.

UBICS researchers M. Ángeles Serrano, Guillermo García-Pérez and Marián Boguñá, who conducted the study published in Nature Physics, applied the renormalization group technique to real systems. “This technique allows us to explore a system at different resolution levels, such as a kind of inverted microscope that allows us to zoom out and widen the scale at which we make the observation”, notes the ICREA research lecturer M. Ángeles Serrano, director of the study.  
“Being able to move around a network at several scales is very important in systems in which you have many interacting elements, such as the networks we studied. These systems are multiscale networks, that is, their structure or associated processes result from a mix of structures and processes at different scales”, says Guillermo García-Pérez, first author of the study. “Each scale has specific data, but scales are also interrelated between them”, he says.  

Representing reality as complex networks
The UB researchers applied the technique they developed to the above mentioned systems. Although they are different, all of them can be defined in the shape of nodes and connections. We know about some cases, such as the Internet; but in others, for example in music, researchers regarded chords as nodes and connections as the proximity of these chords in modern music songs.

In any case, all these systems can be defined as complex networks because they have a property known as small-world, i.e., the nodes are connected between them in a few steps. “It is because of the small-world property that it had been impossible to split structural scales in real complex networks, and in order to do so, we had to develop geometric maps on each one of them so we could define the distances between nodes”, says the lecturer Marián Boguñá.

Moreover, these networks fulfill two more features: on the one hand, they have a heterogeneous connectivity –i.e., there are elements with a high connectivity and others with low connectivity-, and on the other hand, they display many node groupings in a triangular shape (clustering).

“This is the first time a really geometric renormalization group has been defined in complex networks”, notes M. Ángeles Serrano, who adds “We can now build maps of complex networks in the most cartographical sense of the word, real maps where elements or nodes have positions and distance between them”. “These maps –continues the researcher- are not only attractive visual representations but they are full of meaning and they allow us to find out information on the systems and to navigate through them”. In this sense, “we can increase the system navigability if we take into account the information provided by the renormalization group, which allows us to unfold networks at the different scales that build them up, and which, in addition, turn out to be self-similar, that is, they have the same organization at different scales”, highlights the researcher.

These results can also be applied to make reduced versions of the original networks at smaller scales and which have the same properties. “The possibility of having reduced copies has a great potential; for instance, they can serve as a test bench to assess expensive processes in original networks, such as new Internet routing protocols”, concludes Serrano.

Being able to move around a network at several scales is very important in systems in which you have many interacting elements.

Being able to move around a network at several scales is very important in systems in which you have many interacting elements.

These networks fulfill two more features: on the one hand, they have a heterogeneous connectivity –i.e., there are elements with a high connectivity and others with low connectivity-, and on the other hand, they display many node groupings in a triangular shape (clustering).

These networks fulfill two more features: on the one hand, they have a heterogeneous connectivity –i.e., there are elements with a high connectivity and others with low connectivity-, and on the other hand, they display many node groupings in a triangular shape (clustering).

Article reference

G. García-Pérez, M. Boguñá and M. Á. Serrano. “Multiscale unfolding of real complex networks by geometric renormalization”. Nature Physics, March 19, 2018. Doi: 10.1038/s41567-018-0072-5


Symmetries in physical theories denote invariance under some transformation, such as self-similarity under a change of scale. The renormalization group provides a powerful framework to study these symmetries, leading to a better understanding of the universal properties of phase transitions. However, the small-world property of complex networks complicates application of the renormalization group by introducing correlations between coexisting scales. Here, we provide a framework for the investigation of complex networks at different resolutions. The approach is based on geometric representations, which have been shown to sustain network navigability and to reveal the mechanisms that govern network structure and evolution. We define a geometric renormalization group for networks by embedding them into an underlying hidden metric space. We find that real scale-free networks show geometric scaling under this renormalization group transformation. We unfold the networks in a self-similar multilayer shell that distinguishes the coexisting scales and their interactions. This in turn offers a basis for exploring critical phenomena and universality in complex networks. It also affords us immediate practical applications, including high-fidelity smaller-scale replicas of large networks and a multiscale navigation protocol in hyperbolic space, which betters those on single layers.

Mobile World Scholar Challenge

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1 projects 16/02/2018

A video-based competition aimed at discovering and highlighting ground-breaking new technologies developed at universities around the globe.

Embracing new ideas is the key to innovation and growth, be it an economy, an industry, a company, charity or individual. At Mobile World Congress, the largest and most important gathering for the mobile industry in the world, we are constantly looking to showcase cutting edge ideas poised to impact the mobile world.

For MWC 2018, we introduced the Mobile World Scholar Challenge, which highlights new and impactful ideas from the academic and research communities across the globe. Challenge participants submitted short-form videos that promote “the science” as well as the potential “use cases” of their technology research. The more applicable to mobile, the better. Winners receive a cash award and Gold Prize winners will attend Mobile World Congress 2018 as guests of The GSMA.

Silver Prize for two UBICS' members:

Dr. Albert Díaz Guilera and Dr. Josep Perelló, Full Professors at the University of Barcelona

Network Efficiency Based on Mobility

In a hyperconnected world, full of mobile devices whose owners move according to different patterns, depending on their personal characteristics and the environment, we must know how this interconnection and mobility interact.

Thousands of people leaving a sports stadium looking for transport, hundreds of train users arriving simultaneously to the main stations of the big cities looking for a rental bicycle,…These would be two of the possible cases in which users search for the same type of information. Simultaneously, through servers without taking into account the possible interaction between mobile devices in order to save the use of central servers. We must take into account these possible interactions between the devices, but for this we must establish communication protocols that are efficient, based not only on knowledge of the associated technology (both communication and information processing) but also on the connections that they establish with the mobility of the users.

In our group we have investigated in the last years different communication models that depend on mobility. Knowing in detail, even in a statistical way and without going into privacy details, mobility patterns in different types of spaces will help us to design communication protocols that can adapt to those patterns and that communication between devices is more efficient.


The winners for the #MWC18 Mobile World Scholar Challenge have been announced! Discover the winners & watch the ground-breaking technologies developed at universities around the globe here

Researchers find basic mechanisms for root growth and cell replenishment

ub projects 08/02/2018

Understanding the functioning of root biology is crucial to know how plants suffer or adapt to adverse environmental conditions like droughts. Two recent studies describe these kinds of mechanisms: one of them, published in the journal Molecular Systems Biology, describes the process through which cells stop growing due cell differentiation; the second one, published in Journal of Cell Science, describes plants’ cell replenishment after being damaged.

The first study results from the researches carried out by the team of biologist Ana Caño Delgado, CSIC researcher in the Center for Research in Agricultural Genomic (CRAG), and physicist Marta Ibañes, from the Department of Condensed Matter Physics and the Institute of Complex Systems of the University of Barcelona (UBICS). The second study was conducted by the same team in CRAG.

These studies were funded by the Ministry of Economy, Industry and Competitiveness (MINECO), the European Molecular Biology Organization (EMBO), and the European Research Council, and the European Regional Development Fund (FEDER) and the Generalitat de Catalunya.

Article references:

Irina Pavelescu, Josep Vilarrasa-Blasi, Ainoa Planas-Riverola, Mary-Paz González-García, Ana I. Caño-Delgado and Marta Ibañes. «A sizer model for cell differentiation in Arabidopsis thaliana root growth». Molecular Systems Biology, gener de 2018. Doi: 10.15252/msb.20177687


UB researchers identify a mixed-order phase transition

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UBICS people 22/12/2017

UBICS researchers identify a mixed-order phase transition

An article by a team of the University of Barcelona, composed by Ricard Alert, researcher from the Institute of Complex Systems (UBICS); Jaume Casademunt, Professor and researcher from the Institute of Complex Systems (UBICS); and Pietro Tierno, researcher from the Institute of Complex Systems (UBICS)and member of the Institute of Nanoscience and Nanotechnology (IN2UB), published in the journal Proceedings of the National Academy of Sciences (PNAS), shows the theoretical prediction and experimental observation that a mixed-order transition in a magnetic colloidal crystal, that is, a solid formed by a suspension of magnetic microparticles.

Article reference:

R. Alert, P. Tierno, and J. Casademunt. Mixed-order phase transition in a colloidal crystal. Proc. Natl. Acad. Sci. USA 114, 12906 (2017). Doi: 10.1073/pnas.1712584114

4 Beques UBICS: Fi termini 16/10/17

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ubics grants 02/10/2017

Beca UBICS, dedicació 15 hores, període gener-juny 2018, dotació econòmica mensual (import brut) 324,80 € per la col·laboració a través dels Màsters següents el curs 2017-2018:

  • Màster de modelització Computacional atomística i multiescala en física, química i bioquímica
  • Màster de Fonaments de la ciència de dades
  • Màster de Ciència Cognitiva i Llenguatge
  • Màster Interuniversitari en Intel·ligència Artificial (UB, UPC, URV)
  • Màster de Comunicació Especialitzada
  • Màster de Nanociència i Nanotecnologia

Convocatòria i Sol·licitud

UBICS Scholarship, dedication 15 hours, period January-June 2018, monthly financial grant (gross amount) € 324.80 for collaboration through the following Masters in the 2017-2018 course:

  • Master's degree in atomistic and multiscale computational modelling in physics, chemistry and biochemistry
  • Master's degree in Fundamental Principles of Data Science
  • Master's degree in Cognitive Science and Language
  • Interuniversity Master's degree in Artificial Intelligence (UB, UPC, URV)
  • Master's degree in Specialized Communication
  • Master's degree in Nanoscience and Nanotechnology

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