Social engineering is the acquisition of information about computer systems by methods that deeply include non-technical means. While technical security of most critical systems is high, the systems remain vulnerable to attacks from social engineers. Social engineering is a technique that: (i) does not require any (advanced) technical tools, (ii) can be used by anyone, (iii) is cheap. Tradition...

A crisis in chaotic dynamical systems is characterized by the conversion of a nonattracting, Cantorset-like chaotic saddle into a chaotic attractor. The gaps in between various pieces of the chaotic saddle are densely filled after the crisis. We give a quantitative scaling theory for the growth of the topological entropy for a major class of crises, the interior crisis. The theory is confirmed ...

The driver gap acceptance and rejection behavior during mandatory lane changes on a multilane freeway are analyzed in this paper. Gaps are accepted or rejected based on comparison with a minimum value generally defined as the critical gaps. Critical gaps are estimated based on the accepted and rejected gaps observed in the field. Driver behavior can be classified as consistent or inconsistent o...

The chromatic gap is the difference between the chromatic number and the clique number of a graph. Here we investigate gap(n), the maximum chromatic gap over graphs on n vertices. Can the extremal graphs be explored? While computational problems related to the chromatic gap are hopeless, an interplay between Ramsey theory and matching theory leads to a simple and (almost) exact formula for gap(...