Effective time-reversal via periodic shaking

Time reversal in dynamically tuned zero-gap periodic systems.

We show that short pulses propagating in zero-gap periodic systems can be reversed with 100% efficiency by using weak nonadiabatic tuning of the wave velocity at time scales that can be much slower than the period. Unlike previous schemes, we demonstrate reversal of broadband (few cycle) pulses with simple structures. Our scheme may thus open the way to time reversal in a variety of systems for...

Effective Elastic Stiffness for Periodic Masonry Structures via Eigenstrain Homogenization

The equivalent periodic eigenstrain method is used to evaluate the effective elastic stiffness of periodic masonry structure. An Eshelby tensor, for a unit cell of the periodic masonry structure, is derived analytically, and is combined with a strain energy approach to formulate the effective stiffness of the masonry. The new homogenization scheme is simple, one step, and closed form. The model...

Maximal Effective Diffusivity for Time-Periodic Incompressible Fluid Flows

In this paper we establish conditions for the maximal, Pe, behavior of the effective diffusivity in time-periodic incompressible velocity fields for both the Pe oc and Pe 0 limits. Using ergodic theory, these conditions can be interpreted in terms of the Lagrangian time averages of the velocity. We reinterpret the maximal effective diffusivity conditions in terms of a Poincar6 map of the veloci...

Effective periodic pattern mining in time series databases

The goal of analyzing a time series database is to find whether and how frequent a periodic pattern is repeated within the series. Periodic pattern mining is the problem that regards temporal regularity. However, most of the existing algorithms have a major limitation in mining interesting patterns of users interest, that is, they can mine patterns of specific length with all the events sequent...

Effective Stability around Periodic