On the regularity of Mather's β-function for standard-like twist maps

A note on a standard family of twist maps

We investigate the break up of the last invariant curve for analytic families of standard maps Sλ : { y′ = λg(x) + y x′ = x + y′ mod 1 , where g : S →IR is an analytic function such that ∫

“the effect of risk aversion on the demand for life insurance: the case of iranian life insurance market”

abstract: about 60% of total premium of insurance industry is pertained?to life policies in the world; while the life insurance total premium in iran is less than 6% of total premium in insurance industry in 2008 (sigma, no 3/2009). among the reasons that discourage the life insurance industry is the problem of adverse selection. adverse selection theory describes a situation where the inf...

Multiplicative bijective maps on standard operator algebras

Topological Entropy of Standard Type Monotone Twist Maps

We study invariant measures of families of monotone twist maps Sγ(q, p) = (2q−p+γ ·V ′(q), q) with periodic Morse potential V . We prove that there exist a constant C = C(V ) such that the topological entropy satisfies htop(Sγ) ≥ log(C · γ)/3. In particular, htop(Sγ) → ∞ for |γ| → ∞. We show also that there exist arbitrary large γ such that Sγ has nonuniformly hyperbolic invariant measures μγ w...

study of hash functions based on chaotic maps

توابع درهم نقش بسیار مهم در سیستم های رمزنگاری و پروتکل های امنیتی دارند. در سیستم های رمزنگاری برای دستیابی به احراز درستی و اصالت داده دو روش مورد استفاده قرار می گیرند که عبارتند از توابع رمزنگاری کلیددار و توابع درهم ساز. توابع درهم ساز، توابعی هستند که هر متن با طول دلخواه را به دنباله ای با طول ثابت تبدیل می کنند. از جمله پرکاربردترین و معروف ترین توابع درهم می توان توابع درهم ساز md4, md...