A Theoretical Basis for Entropy-Scaling Effects in Human Mobility Patterns.

Autor: Nathaniel D Osgood, Tuhin Paul, Kevin G Stanley, Weicheng Qian
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: PLoS ONE, Vol 11, Iss 8, p e0161630 (2016)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0161630
Popis: Characterizing how people move through space has been an important component of many disciplines. With the advent of automated data collection through GPS and other location sensing systems, researchers have the opportunity to examine human mobility at spatio-temporal resolution heretofore impossible. However, the copious and complex data collected through these logging systems can be difficult for humans to fully exploit, leading many researchers to propose novel metrics for encapsulating movement patterns in succinct and useful ways. A particularly salient proposed metric is the mobility entropy rate of the string representing the sequence of locations visited by an individual. However, mobility entropy rate is not scale invariant: entropy rate calculations based on measurements of the same trajectory at varying spatial or temporal granularity do not yield the same value, limiting the utility of mobility entropy rate as a metric by confounding inter-experimental comparisons. In this paper, we derive a scaling relationship for mobility entropy rate of non-repeating straight line paths from the definition of Lempel-Ziv compression. We show that the resulting formulation predicts the scaling behavior of simulated mobility traces, and provides an upper bound on mobility entropy rate under certain assumptions. We further show that this formulation has a maximum value for a particular sampling rate, implying that optimal sampling rates for particular movement patterns exist.
Databáze: Directory of Open Access Journals