Given a set P of n points on the real line and a (potentially in nite) family of functions, we investigate the problem of nding a small (weighted) subset S ⊆ P , such that for any f ∈ F, we have that f(P ) is a (1 ± ε)-approximation to f(S). Here, f(Q) = ∑ q∈Q w(q)f(q) denotes the weighted discrete integral of f over the point set Q, where w(q) is the weight assigned to the point q. We study th...

In this paper , we prove the first approximate max-flow min-cut theorem for undirected mul t i commodi ty flow. We show tha t for a feasible flow to exist in a mul t icommodi ty problem, it is sufficient t ha t every cut ' s capacity exceeds its demand by a factor of O(logClogD), where C is the sum of all finite capacities and D is the sum of demands . Moreover, our theorem yields an a lgor i t...

this paper considers a two-stage assembly flow shop problem (tafsp) where m machines are in the first stage and an assembly machine is in the second stage. the objective is to minimize a weighted sum of earliness and tardiness time for n available jobs. jit seeks to identify and eliminate waste components including over production, waiting time, transportation, inventory, movement and defective...

This paper considers the economic lot and delivery scheduling problem in a two-echelon supply chains, where a single supplier produces multiple components on a flexible flow line (FFL) and delivers them directly to an assembly facility (AF). The objective is to determine a cyclic schedule that minimizes the sum of transportation, setup and inventory holding costs per unit time without shortage....

The ideas and results contained in this document are part of my thesis, which will be published as a Stanford computer science technical report in June 1999. Similar ideas applied to the EMD under translation have already been published in the technical report [1]. We begin some intuition, examples, and informal definitions. The Earth Mover's Distance (EMD) is a distance measure between discret...

We prove a strong version of the the Max-Flow Min-Cut theorem for countable networks, namely that in every such network there exist a flow and a cut that are “orthogonal” to each other, in the sense that the flow saturates the cut and is zero on the reverse cut. If the network does not contain infinite trails then this flow can be chosen to be mundane, i.e. to be a sum of flows along finite pat...

In this paper we study the conjugacy problem in polycyclic groups. Our main result is that we create polycyclic groups Gn whose conjugacy problem is at least as hard as the subset sum problem with n indeterminates. As such, the conjugacy problem over the groups Gn is NP-complete where the parameters of the problem are taken in terms of n and the length of the elements given on input.

This article considers a two-player strategic game for network routing under link disruptions. Player 1 (defender) routes flow through a network to maximize her value of effective flow while facing transportation costs. Player 2 (attacker) simultaneously disrupts one or more links to maximize her value of lost flow but also faces cost of disrupting links. Linear programming duality in zero-sum ...