In this paper, we present an analysis of the strength of sparse cutting-planes for mixed integer linear programs (MILP) with sparse formulations. We examine three kinds of problems: packing problems, covering problems, and more general MILPs with the only assumption that the objective function is non-negative. Given a MILP instance of one of these three types, assume that we decide on the suppo...

Sparse cutting-planes are often the ones used in mixed-integer programing (MIP) solvers, since they help in solving the linear programs encountered during branch-&-bound more efficiently. However, how well can we approximate the integer hull by just using sparse cuttingplanes? In order to understand this question better, given a polyope P (e.g. the integer hull of a MIP), let P be its best appr...

In this paper, the use of beam search and look-ahead strategies for solving the strip packing problem (SPP) is investigated. Given a strip of fixed width W, unlimited length L, and a set of n circular pieces of known radii, the objective is to determine the minimum length of the initial strip that packs all the pieces. An augmented algorithm which combines beam search and a look-ahead strategie...

Brass Ferrules have been used as packing in a laboratory- scale glass distillation column approaching pilot plant size because of their availability in all sizes and low cost. The available size range is such that these ferrules could also be used in industry and the results of this study could be scaled up. The performance of the new packing has been compared with the performance of glass ...

We present PackLib, the first fully integrated benchmark library for multi-dimensional packing instances. PackLib combines a systematic collection of all benchmark instances from previous literature with a well-organized set of new and challenging large instances. The XML format allows linking basic benchmark data with other important properties, like bibliographic information, origin, best kno...

We present PackLib, the first fully integrated benchmark library for multi-dimensional packing instances. PackLib combines a systematic collection of all benchmark instances from previous literature with a well-organized set of new and challenging large instances. The XML format allows linking basic benchmark data with other important properties, like bibliographic information, origin, best kno...

We present PackLib, the first fully integrated benchmark library for multi-dimensional packing instances. PackLib combines a systematic collection of all benchmark instances from previous literature with a well-organized set of new and challenging large instances. The XML format allows linking basic benchmark data with other important properties, like bibliographic information, origin, best kno...

It is shown that a packing of unit spheres in three-dimensional Euclidean space can have density at most 0.773055 .... and that a Voronoi polyhedron defined by such a packing must have volume at least 5.41848 .... These bounds are superior to the best bounds previously published [5] (0.77836 and 5.382, respectively), but are inferior to the tight bounds of 0.7404... and 5.550... claimed by Hsia...

We consider the feasibility problem OPP in higher-dimensional orthogonal packing: given a set of d-dimensional (d ≥ 2) rectangular items, decide whether all of them can be orthogonally packed in the given rectangular container without rotation. The 1D ‘bar’ LP relaxation of OPP reduces the latter to a 1D cutting-stock problem where the packing of each stock bar represents a possible 1D stitch t...

In a previous paper, pressure drop, flooding and mass-transfer characteristics of a novel pilot-scale distillation column called spinning cone column (SCC) were presented. Here, we present the result of comparison of mass-transfer efficiencies of SCC and structured packing. Comparison of SCC and structured packing mass-transfer characteristics show that the gas and liquid-side height of transfe...