agegraphic DE models to reconstruct the form of $f(R)$ suitable to explain the unification of early time inflation and late time acceleration. The idea that the Heisenberg uncertainty principle could be affected by gravity was given by Mead [@new19]. In the regime when the gravity is strong enough, conventional Heisenberg uncertainty relation is no longer satisfactory (though approximately but perfectly valid in low gravity regimes). Modified commutation relations between position and momenta commonly known as the generalized uncertainty principle (or GUP) were given by candidate theories of quantum gravity like string theory, doubly special relativity and black hole physics with the prediction of a minimum measurable length. Importance of the GUP can also be realized on the basis of simple gedanken experiments without any reference of a particular fundamental theory [@new27; @new28]. So we can think the GUP as a model-independent concept suitable for the study of black hole entropy at least phenomenologically.

According to the holographic principle the number of degrees of freedom of a bounded system should be finite and is related to the area of its boundary. As an application of the principle the upper bound of the entropy of the universe can be obtained. The total 