Lower bound of admissible functions on sphere

Sphere packing lower bound on fingerprinting error probability

We study the statistical performance of spherical fingerprints for a focused detector which decides whether a user of interest is among the colluders. The colluders create a noise-free forgery by preprocessing their individual copies, and then adding a white Gaussian noise sequence to form the actual forgery. Let N be the codelength, M the number of users, and K the number of colluders. We deri...

Lower Bound Functions for Polynomials

Lower bound on complexity of optimization of continuous functions

This paper considers the problem of approximating the minimum of a continuous function using a fixed number of sequentially selected function evaluations. A lower bound on the complexity is established by analyzing the average case for the Brownian bridge.

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...

Lower Bound on Weights of Large Degree Threshold Functions

An integer polynomial p of n variables is called a threshold gate for a Boolean function f of n variables if for all x ∈ {0, 1} f(x) = 1 if and only if p(x) > 0. The weight of a threshold gate is the sum of its absolute values. In this paper we study how large a weight might be needed if we fix some function and some threshold degree. We prove 2 ) lower bound on this value. The best previous bo...