743 research outputs found
An Improved Upper Bound for the Ring Loading Problem
The Ring Loading Problem emerged in the 1990s to model an important special
case of telecommunication networks (SONET rings) which gained attention from
practitioners and theorists alike. Given an undirected cycle on nodes
together with non-negative demands between any pair of nodes, the Ring Loading
Problem asks for an unsplittable routing of the demands such that the maximum
cumulated demand on any edge is minimized. Let be the value of such a
solution. In the relaxed version of the problem, each demand can be split into
two parts where the first part is routed clockwise while the second part is
routed counter-clockwise. Denote with the maximum load of a minimum split
routing solution. In a landmark paper, Schrijver, Seymour and Winkler [SSW98]
showed that , where is the maximum demand value. They
also found (implicitly) an instance of the Ring Loading Problem with . Recently, Skutella [Sku16] improved these bounds by showing that , and there exists an instance with .
We contribute to this line of research by showing that . We
also take a first step towards lower and upper bounds for small instances
Proceedings of the 8th Cologne-Twente Workshop on Graphs and Combinatorial Optimization
International audienceThe Cologne-Twente Workshop (CTW) on Graphs and Combinatorial Optimization started off as a series of workshops organized bi-annually by either Köln University or Twente University. As its importance grew over time, it re-centered its geographical focus by including northern Italy (CTW04 in Menaggio, on the lake Como and CTW08 in Gargnano, on the Garda lake). This year, CTW (in its eighth edition) will be staged in France for the first time: more precisely in the heart of Paris, at the Conservatoire National d’Arts et Métiers (CNAM), between 2nd and 4th June 2009, by a mixed organizing committee with members from LIX, Ecole Polytechnique and CEDRIC, CNAM
- …