This paper is a survey about recent results on sparse representations and optimal models in different settings. Given a set of functions, we show that there exists an optimal collection of subspaces minimizing the sum of the square of the distances between each function and its closest subspace in the collection. Further, this collection of subspaces gives the best sparse representation for the...

The purpose of this paper is to studying nonlinear k-ε turbulence models and its advantages in internal combustion engines, since the standard k-ε model is incapable of representing the anisotropy of turbulence intensities and fails to express the Reynolds stresses adequately in rotating flows. Therefore, this model is not only incapable of expressing the anisotropy of turbulence in an engine c...

in this work, removal of c. i. acid red 14 was investigated by pumice stone as a low cost adsorbent. various parameters such as initial dye solution, contact time and ph were studied. removal of dye were increased by increasing of contact time and initial dye solution and deceased by increasing of ph. three isotherm models were studied. linear and non-linear regression analyses were used for de...