Events

New Nonlinear Functions for S-Boxes in Cryptography and their Fourier Transform

Abstract:

Functions used in S-Boxes in block ciphers are required to be highly nonlinear in order to be resistant to linear cryptanalysis. This property is related to the Fourier spectrum of the function.

Greedy Algorithms and Complexity for Nonnegative Matrix Factorization

Abstract:

Nonnegative Matrix Factorization (NMF) has emerged in the past decade as an important tool for information retrieval and clustering.

The Resolution Complexity of Random Constraint Satisfaction Problems

Abstract:

Constraint satisfaction problems (CSP's) are generalizations of CNF boolean formulas. We are given a set of variables, and a domain of values that the variables can take.

Gradient Methods for Minimizing Composite Objective Function

Abstract:

In this talk we present several methods for solving optimization problems with the objective function formed as a sum of two convex terms: one is smooth and given by a black-box oracle, and another is general but simple and it

Electrical Networks, Random Spanning Trees, and Correlation Inequalities

Abstract:

In 1847 Kirchhoff derived a beautiful formula for the effective conductance of an electrical network G: it is a rational function of the edge conductances, and both the numerator and the denominator are generating f

Image Segmentation using Spectral Graph Theory

Abstract:

In this talk we present a new image segmentation algorithm, Spectral Rounding (SR), and a fast solver. The combination is used for segmenting 2D and 3D images.

Codeword Stabilized Quantum Codes

Abstract:

I will describe an approach to quantum error correcting code design that encompasses additive (stabilizer) codes, as well as all known examples of nonadditive codes with good parameters.

The KP hierarchy, branched covers and triangulations

Abstract:

The KP hierarchy is a system of quadratic partial differential equations that arises in mathematical physics, and generalizes the KdV hierarchy.

Growth rates of minor-closed classes of matroids

Abstract:

For a minor-closed class $\cM$ of matroids, we let $h(k)$ denote the maximum number of elements of a simple rank-$k$ matroid in $\cM$.

2-crossing-critical graphs

Abstract:

A graph G is k-crossing-critical if its crossing number is at least k, but every proper subgraph has crossing number at most k-1. (We may assume minimum degree at least 3.) The only 1-crossing-critical graphs arise from Kuratowski's Theorem.