Month: December 2016

Detection of timescales in evolving complex systems

Most complex systems are intrinsically dynamic in nature. The evolution of a dynamic complex system is typically represented as a sequence of snapshots, where each snapshot describes the configuration of the system at a particular instant of time. This is often done by using constant intervals but a better approach would be to define dynamic intervals that match the evolution of the system’s configuration. To this end, we propose a method that aims at detecting evolutionary changes in the configuration of a complex system, and generates intervals accordingly. We show that evolutionary timescales can be identified by looking for peaks in the similarity between the sets of events on consecutive time intervals of data. Tests on simple toy models reveal that the technique is able to detect evolutionary timescales of time-varying data both when the evolution is smooth as well as when it changes sharply. This is further corroborated by analyses of several real datasets. Our method is scalable to extremely large datasets and is computationally efficient. This allows a quick, parameter-free detection of multiple timescales in the evolution of a complex system.


Detection of timescales in evolving complex systems
Richard K. Darst, Clara Granell, Alex Arenas, Sergio Gómez, Jari Saramäki & Santo Fortunato

Scientific Reports 6, Article number: 39713 (2016)


Explaining the prevalence, scaling and variance of urban phenomena

The prevalence of many urban phenomena changes systematically with population size 1 . We propose a theory that unifies models of economic complexity 2,3 and cultural evolution 4 to derive urban scaling. The theory accounts for the difference in scaling exponents and average prevalence across phenomena, as well as the difference in the variance within phenomena across cities of similar size. The central ideas are that a number of necessary complementary factors must be simultaneously present for a phenomenon to occur, and that the diversity of factors is logarithmically related to population size. The model reveals that phenomena that require more factors will be less prevalent, scale more superlinearly and show larger variance across cities of similar size. The theory applies to data on education, employment, innovation, disease and crime, and it entails the ability to predict the prevalence of a phenomenon across cities, given information about the prevalence in a single city.


Explaining the prevalence, scaling and variance of urban phenomena
Andres Gomez-Lievano, Oscar Patterson-Lomba & Ricardo Hausmann

Nature Human Behaviour 1, Article number: 0012 (2016)


A “Social Bitcoin” could sustain a democratic digital world

A multidimensional financial system could provide benefits for individuals, companies, and states. Instead of top-down control, which is destined to eventually fail in a hyperconnected world, a bottom-up creation of value can unleash creative potential and drive innovations. Multiple currency dimensions can represent different externalities and thus enable the design of incentives and feedback mechanisms that foster the ability of complex dynamical systems to self-organize and lead to a more resilient society and sustainable economy. Modern information and communication technologies play a crucial role in this process, as Web 2.0 and online social networks promote cooperation and collaboration on unprecedented scales. Within this contribution, we discuss how one dimension of a multidimensional currency system could represent socio-digital capital (Social Bitcoins) that can be generated in a bottom-up way by individuals who perform search and navigation tasks in a future version of the digital world. The incentive to mine Social Bitcoins could sustain digital diversity, which mitigates the risk of totalitarian control by powerful monopolies of information and can create new business opportunities needed in times where a large fraction of current jobs is estimated to disappear due to computerisation.


A “Social Bitcoin” could sustain a democratic digital world

Kleineberg, KK. & Helbing, D. Eur. Phys. J. Spec. Top. (2016) 225: 3231. doi:10.1140/epjst/e2016-60156-7


Call | NetSci 2017


International School and Conference on Network Science 

June 19-23, Indianapolis, IN (JW Marriott Indianapolis)  |



December 15, 2016: Deadline for Satellite Symposia proposals

January 15, 2017: Deadline for abstract submission of oral presentations, lightning talks, and posters

March 1, 2017: Deadline for Erdös–Rényi Prize nomination



Keynote Speakers: Danielle S. Bassett  (U Penn), Steve Borgatti (U Kentucky), Jennifer A. Dunne (Sante Fe Institute)

Invited Speakers: Meeyoung Cha (KAIST), Alex Fornito (Monash U), Lise Getoor (UC Santa Cruz), César A. Hidalgo (MIT),  Shawndra Hill (Microsoft Research NYC & U Penn), M. Ángeles Serrano, (U Barcelona), Roberta Sinatra  (Central European U), Xiaofan Wang (Shanghai Jiao Tong U)



NetSci 2017, the International School and Conference on Network Science, will be held in Indianapolis, Indiana from June 19 to 23, 2017. NetSci 2017 aims to bring together leading researchers and practitioners working in the emerging area of network science. The conference fosters interdisciplinary communication and collaboration in network science research across computer and information sciences, physics, mathematics, statistics, the life sciences, neuroscience, environmental sciences, social sciences, finance and business, arts and design.


NetSci 2017 is a combination of:

  • Satellite Symposia (June 19 & 20)
  • An International School for students and non-experts (June 19 & 20)
  • A 3-day Conference (June 21-23) featuring research in a wide range of topics and in different formats, including keynote and invited talks, oral presentations, posters, and lightning talks.



Following the successful tradition of this conference, NetSci 2017 will host several Satellite Symposia on June 19 and 20 as precursors of the main Conference. These satellite events are one-day or half-day meetings with a focus on a specific topic of Network Science and its Applications. All subjects are welcome, but we would specifically support proposals on themes such as: Multilayer, Interdependent and/or Temporal Networks, Critical Infrastructures, Financial Networks, Biological Networks, Brain Networks, and Computational Social Sciences. Details for proposals, due December 15, can be found here:



To submit an abstract for an a oral presentation (15 mins, with 5 minute Q&A), lightning talk (5 mins), or poster, please prepare a one-page abstract including one mandatory descriptive figure and caption plus three keywords. The deadline for submission is Friday, January 15, 2017, with decisions issued by March 1. The abstract submission portal will be live on November 1, and will be available here: You must use one of the two provided templates for preparing your abstract, also available at that page.



The Erdös–Rényi Prize is awarded each year to a selected young scientist (under 40 years old on the day of the nomination deadline) for their achievements in research activities in the area of network science, broadly construed. While the achievements can be both theoretical and experimental, the prize is aimed at emphasizing outstanding contributions relevant to the interdisciplinary progress of network science. Candidate dossiers are due March 1, 2017 and self-nominations are not accepted. Details can be found at:


SATELLITE CO-CHAIRS: Réka Albert (Pennsylvania State University) & Filippo Radicchi (Indiana University Bloomington)

PROGRAM COMMITEE CO-CHAIRS: Yong-Yeol Ahn (Indiana University Bloomington), Ciro Cattuto (ISI Foundation) & Tina Eliassi-Rad (Northeastern University)

SCHOOL CO-CHAIRS: Santo Fortunato (Indiana University Bloomington) & M. Ángeles Serrano (Universitat de Barcelona)

CONFERENCE CO-CHAIRS: Fil Menczer and Olaf Sporns (Indiana University Bloomington)

SPONSORSHIP CO-CHAIRS: Giovanni Ciampaglia and Alessandro Flammini (Indiana University Bloomington)


NetSci 2017 is hosted by the Indiana University Network Science Institute ( It is the annual meeting of the Network Science Society (


Questions? Email and  

Follow us on Twitter and Facebook: @NetSci2017



Characteristics of the evolution of cooperation by the probabilistic peer-punishment based on the difference of payoff

Regarding costly punishment of two types, especially peer-punishment is considered to decrease the average payoff of all players as well as pool-punishment does, and to facilitate the antisocial punishment as a result of natural selection. To solve those problems, the author has proposed the probabilistic peer-punishment based on the difference of payoff. In the limited condition, the proposed peer-punishment has shown the positive effects on the evolution of cooperation, and increased the average payoff of all players.

Based on those findings, this study exhibits the characteristics of the evolution of cooperation by the proposed peer-punishment. Those characteristics present the significant contribution to knowledge that for the evolution of cooperation, a limited number of players should cause severe damage to defectors at the large expense of their payoff when connections between them are sparse, whereas a greater number of players should share the responsibility to punish defectors at the relatively small expense of their payoff when connections between them are dense.


Characteristics of the evolution of cooperation by the probabilistic peer-punishment based on the difference of payoff

Tetsushi Ohdaira

Chaos, Solitons & Fractals
Volume 95, February 2017, Pages 77–83