Regime shifts are large, long-lasting changes in ecosystems. They are often hard to predict but may have leading indicators which are detectable in advance. Potential leading indicators include wider swings in dynamics of key ecosystem variables, slower return rates after perturbation and shift of variance towards lower frequencies. We evaluated these indicators using a food web model calibrate...

We propose a temporal mean shift algorithm that clusters spatio-temporal regions in video by exploiting the temporal nature of video. Extracting spatio-temporal regions is often one of the first pre-processing steps in an activity recognition system. Our key contribution is the insight that mean shift clustering can exploit the fact that there is typically very little change between successive ...

We consider a type of dependent percolation introduced in [2], where it is shown that certain “enhancements” of independent (Bernoulli) percolation, called essential, make the percolation critical probability strictly smaller. In this paper we first prove that, for two-dimensional enhancements with a natural monotonicity property, being essential is also a necessary condition to shift the criti...