Volume 81, Number 4, February 2008
Article Number 48002
Number of page(s) 5
Section Interdisciplinary Physics and Related Areas of Science and Technology
Published online 17 January 2008
EPL, 81 (2008) 48002
DOI: 10.1209/0295-5075/81/48002

Burstiness and memory in complex systems

K.-I. Goh1, 2 and A.-L. Barabási1, 3

1  Center for Complex Network Research and Department of Physics, University of Notre Dame Notre Dame, IN 46556, USA
2  Department of Physics, Korea University - Seoul 136-713, Korea
3  Department of Physics, Biology, and Computer Science, Northeastern University - Boston, MA 02115, USA

received 9 September 2007; accepted in final form 13 December 2007; published February 2008
published online 17 January 2008

The dynamics of a wide range of real systems, from email patterns to earthquakes, display a bursty, intermittent nature, characterized by short timeframes of intense activity followed by long times of no or reduced activity. The understanding of the origin of such bursty patterns is hindered by the lack of tools to compare different systems using a common framework. Here we propose to characterize the bursty nature of real signals using orthogonal measures quantifying two distinct mechanisms leading to burstiness: the interevent time distribution and the memory. We find that while the burstiness of natural phenomena is rooted in both the interevent time distribution and memory, for human dynamics memory is weak, and the bursty character is due to the changes in the interevent time distribution. Finally, we show that current models lack in their ability to reproduce the activity pattern observed in real systems, opening up avenues for future work.

89.75.-k - Complex systems.
05.45.Tp - Time series analysis.

© EPLA 2008