We develop a randomized algorithm for the k-level facility location problem that is guaranteed to find a feasible solution of expected cost within a factor of 3 of the optimum cost.Expand

We obtain a 1.5-approximation algorithm for the metric uncapacitated facility location (UFL) problem, which improves on the previously best known 1.52 algorithm by Mahdian, Ye, and Zhang.Expand

We consider the following integer feasibility problem: Given positive integer numbersa0,a1, ... , a n , with gcd( a1,..., a n ) = 1 anda = ( a1,..., a n ), does there exist a vectorx?Z n… Expand

We study the two-level uncapacitated facility location (TUFL) problem. Given two types of facilities, which we call y-facilities and z-facilities, the problem is to decide which facilities of both… Expand

We develop an algorithm for solving a system of diophantine equations with lower and upper bounds on the variables, based on lattice basis reduction.Expand

This paper reports on the factorization of the 512-bit number RSA-155 by the Number Field Sieve method (NFS) and discusses the implications for RSA.Expand