we investigate the growth of matter density perturbations as well as the generalized second law (gsl) of thermodynamics in the framework of f(r)-gravity. we consider a spatially flat frw universe filled with the pressureless matter and radiation which is enclosed by the dynamical apparent horizon with the hawking temperature. for some viable f(r) models containing the starobinsky, hu-sawicki, exp...

The gravity vector theory postulates that birds determine their position to set a home course by comparing the memorized gravity vector at the home loft with the local gravity vector at the release site, and that they should adjust their flight course to the gravity anomalies encountered. As gravity anomalies are often intermingled with geomagnetic anomalies, we released experienced pigeons fro...

in this paper, a novel method for ranking of fuzzy numbers are proposed. in this method, decision maker is defined based on the center of mass at some cuts of a pair of fuzzy numbers in discreet version and center of mass on all of cuts of a pair of fuzzy numbers in continuous version. our method can rank more than two fuzzy numbers simultaneously. also, some properties of methods are described...

This paper shows roll and pitch feedback control on a coaxial mini helicopter equipped with a center of gravity steering mechanism. The helicopter carries a minimal set of sensors to measure yaw rate, distance to ground and roll and pitch angle. While yaw rate and distance to ground control are already realized on the helicopter, roll and pitch control including the necessary signal filtering a...