Air quality and transport behaviour: sensors, field, and survey data from Warsaw, Poland.

The present study describes the data sets produced in Warsaw, Poland with the aim of developing tools and methods for the implementation of human-centred and data-driven solutions to the enhancement of sustainable mobility transition. This study focuses on school commutes and alternatives to private cars for children drop off and pick up from primary schools. The dataset enables the complex analysis of interactions between determinants of transport mode choice, revealed choices, and air quality impact.

Chaotic maps derived from trajectory data.

We assume that we have the following information from observed trajectory data about a discrete time dynamical process: (1) a rough graph of the phase plot, (2) the probability density function and (3) the metric entropy. We describe a method for constructing a nonlinear map whose graph is "within" the rough graph of the phase plot, and which has the observed probability density function and entropy.(c) 2002 American Institute of Physics.

Iterated function systems and dynamical systems.

We study the relationship between measures invariant for a piecewise expanding transformation tau of a compact metric space endowed with a underlying measure and measures invariant for an iterated function system T(tau), generated by inverse branches of tau. The main result says that the tau-invariant absolutely continuous measure &mgr; is also T(tau) invariant if and only if tau is absolutely continuously conjugated with a piecewise linear transformation. Measures of maximal entropy and general equilibrium states are also discussed.