We consider a biased nearest-neighbor random walk on Z which at each step is trapped for some time with random, site-dependent mean. derive simple formula the speed function in terms of model parameters.

An oracle chooses a function f from the set of n bits strings to itself, which is either a randomly chosen permutation or a randomly chosen function. When queried by an n-bit string w, the oracle computes f(w), truncates the m last bits, and returns only the first n −m bits of f(w). How many queries does a querying adversary need to submit in order to distinguish the truncated permutation from ...

the permeability and tortuosity of pore-scale two and three-dimensional random porous media were calculated using the lattice boltzmann method (lbm). effects of geometrical parameters of medium on permeability and tortuosity were investigated as well. two major models of random porous media were reconstructed by computerized tomography method: randomly distributed rectangular obstacles in a uni...