Bursty behaviour found to have similar features across complex systems

Jun 01, 2012

Several complex systems live in periods of short bursts of high activity followed by long uneventful intermissions. This phenomenon called burstiness can be modelled and predicted with mathematical algorithms. Research of Dr Márton Karsai of Aalto University Department of Biomedical Engineering and Computational Science, now shows that burstiness has universal features in very different systems.

Karsai and his collaborators – Dean Kimmo Kaski of Aalto University School of Science, FidiPro Professor in Aalto University János Kertész, and the world-renowned physicist and network theorist Professor Albert-László Barabási – studied burstiness in human mobile and email communication, in neuron spike trains, and in seismic activity in earthquakes. The results have recently been published in Nature Scientific Reports.

"The method we developed helped us to highlight a novel universal feature of bursty behaviour. This is one step beyond the state of the art assumptions regarding the phenomena of burstiness," assesses Karsai the significance of the group's work.

The research focuses on the dynamic phenomena of burstiness, that is, the mechanisms of temporal fluctuation of levels of activity. We make, for instance, several phone calls and send many emails in a short spurts of time, and otherwise not so much. Neurons fire in spike trains, and earth quakes in similar temporal patterns.

There are not only connections between consecutive events but also in events within bursty periods.

The common feature shared by the studied systems is that beyond being bursty, the bursty events evolve rather in long trains of events than in pairs – contrary to what existing modelling methods have lead to assume.

"We observed that bursts are not independent but rather clustered and they evolve in long bursty trains, which contain several correlated events. The universality of the analysed systems come from the fact that the size distribution of these trains scale very similarly in human communication, neuron firing and earthquakes," describes Karsai the group's results.

All the systems share both a threshold mechanism of a sort and memory effects within their processes. Earth begins to shake when accumulated stress relaxes, and one quake can trigger several aftershocks. Neurons fire in consecutive spike trains when they receive enough excitatory stimuli. Humans make choices between countless virtual options; one phone call or email often turns into many.

"These correlations can be interpreted as a very simple memory process where the actual state of the system depends not only on the previous bursty event but also from all the other events that have evolved in the actual burst train," points out Karsai.

"We hope that our approach will help to disclose other unknown features of correlated heterogeneous temporal behaviour. The methodology can be applied in many different fields of science, engineering and business. For instance, by predicting human communication behaviour, one can better design the usage of resources in telecommunication or help service providers make better business plans."

Explore further: Mathematicians analyse new 'racetrack memory' computer device

More information: The original article by Márton Karsai, Kimmo Kaski, Albert-László Barabási & János Kertész (2012) 'Universal features of correlated bursty behaviour', Nature Scientific Reports (2) 397. www.nature.com/srep/2012/12050… /full/srep00397.html

add to favorites email to friend print save as pdf

Related Stories

Study finds human communication is 'bursty'

Sep 14, 2011

Researchers in Spain have investigated the temporal patterns of human communication and how the latter impacts the spread of information in social networks. The results, published in the journal Physical Re ...

Brain activity revealed when watching a feature film

May 29, 2012

Human brain functions have been studied in the past using relatively simple stimuli, such as pictures of faces and isolated sounds or words. Researchers from Aalto University Department of Biomedical Engineering and Computational ...

In an emergency, word spreads fast and far

Apr 04, 2011

(PhysOrg.com) -- Large-scale emergencies, such as bombings and plane crashes, trigger a sharp spike in the number of phone calls and text messages sent by eyewitnesses in the vicinity of the disaster, according ...

Getting inside the control mechanisms of complex systems

May 13, 2011

Northeastern University researchers are offering a fascinating glimpse into how greater control of complex systems, such as cellular networks and social media, can be achieved by merging the tools of network ...

What the brain saw

Mar 31, 2011

The moment we open our eyes, we perceive the world with apparent ease. But the question of how neurons in the retina encode what we "see" has been a tricky one. A key obstacle to understanding how our brain ...

Nurturing a seed of discovery

Aug 09, 2011

(PhysOrg.com) -- Network scientists at Northeastern University have collaborated with an interdisciplinary team of colleagues in cell biology and interactive data acquisition to create the first large-scale map of a plant’s ...

Recommended for you

Soccer's key role in helping migrants to adjust

2 hours ago

New research from the University of Adelaide has for the first time detailed the important role the sport of soccer has played in helping migrants to adjust to their new lives in Australia.

How dinosaurs shrank, survived and evolved into birds

3 hours ago

That starling at your birdfeeder? It is a dinosaur. The chicken on your dinner plate? Also a dinosaur. That mangy seagull scavenging for chips on the beach? Apart from being disgusting, yet again it is a ...

Children's book explores Really Big Numbers

4 hours ago

A new children's book written and illustrated by a Brown mathematics professor Richard Schwartz takes readers on a visual journal through the infinite number system. Schwartz hopes Really Big Numbers will ...

User comments : 0