  Human movements in the real world and in cyberspace affect not only dynamical
processes such as epidemic spreading and information diffusion but also social
and economical activities such as urban planning and personalized
recommendation in online shopping. Despite recent efforts in characterizing and
modeling human behaviors in both the real and cyber worlds, the fundamental
dynamics underlying human mobility have not been well understood. We develop a
minimal, memory-based random walk model in limited space for reproducing, with
a single parameter, the key statistical behaviors characterizing human
movements in both spaces. The model is validated using big data from mobile
phone and online commerce, suggesting memory-based random walk dynamics as the
universal underpinning for human mobility, regardless of whether it occurs in
the real world or in cyberspace.
