On the differential approximation of MIN SET COVER

Differential approximations for min set cover

We present in this paper differential approximation results for min set cover and min weighted set cover. We first show that the differential approximation ratio of the natural greedy algorithm for min set cover is bounded below by 1.365/∆ and above by 4/(∆+1), where ∆ is the maximum set-cardinality in the min set cover-instance. Next we study another approximation algorithm for min set cover t...

Automatic QoS-aware Web Services Composition based on Set-Cover Problem

By definition, web-services composition works on developing merely optimum coordination among a number of available web-services to provide a new composed web-service intended to satisfy some users requirements for which a single web service is not (good) enough. In this article, the formulation of the automatic web-services composition is proposed as several set-cover problems and an approxima...

On the differential approximation of MIN SET COVER (juin 2004)

Optimal order finite element approximation for a hyperbolic‎ ‎integro-differential equation

‎Semidiscrete finite element approximation of a hyperbolic type‎ ‎integro-differential equation is studied. The model problem is‎ ‎treated as the wave equation which is perturbed with a memory term.‎ ‎Stability estimates are obtained for a slightly more general problem.‎ ‎These, based on energy method, are used to prove optimal order‎ ‎a priori error estimates.‎

Topological structure on generalized approximation space related to n-arry relation

Classical structure of rough set theory was first formulated by Z. Pawlak in [6]. The foundation of its object classification is an equivalence binary relation and equivalence classes. The upper and lower approximation operations are two core notions in rough set theory. They can also be seenas a closure operator and an interior operator of the topology induced by an equivalence relation on a u...