EPL, 79 (2007) 30003
DOI: 10.1209/0295-5075/79/30003

Emergence of bi-fractal time series from noise via allometric filters

N. Scafetta¹ and B. J. West<sup>1, 2

1</sup>  Department of Physics, Duke University - Durham, NC 27708, USA
²  Mathematical & Information Science Directorate Army Research Office - Research Triangle Park, NC 27709, USA

received 10 April 2007; accepted in final form 13 June 2007; published August 2007
published online 16 July 2007

Abstract
We show how fractal time series can naturally emerge from an input signal, which might be also random noise, when processed by some allometric mechanisms. In particular, we introduce and study the properties of allometric low and high-pass filters. We also argue that in nature pure monofractal signals could be unphysical, while bi-scaling signals might be extremely common, a fact that might be due to allometric geometrical constraint. Finally, we suggest how allometric physical mechanisms could give an approximative interpretation of the fractional calculus.

PACS
05.30.Pr - Fractional statistics systems (anyons, etc.).
89.75.Da - Systems obeying scaling laws.
05.45.Df - Fractals.

© Europhysics Letters Association 2007