Conservative scales in packing problems

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • G. Belov - , TUD Dresden University of Technology (Author)
  • V. Kartak - , Ufa State Aviation Technical University (Author)
  • H. Rohling - , TUD Dresden University of Technology (Author)
  • G. Scheithauer - , Chair of Numerical Optimization (Author)

Abstract

Packing problems (sometimes also called cutting problems) are combinatorial optimization problems concerned with placement of objects (items) in one or several containers. Some packing problems are special cases of several other problems such as resource-constrained scheduling, capacitated vehicle routing, etc. In this paper we consider a bounding technique for one- and higher-dimensional orthogonal packing problems, called conservative scales (CS) (in the scheduling terminology, redundant resources). CS are related to the possible structure of resource consumption: filling of a bin, distribution of the resource to the jobs, etc. In terms of packing, CS are modified item sizes such that the set of feasible packings is not reduced. In fact, every CS represents a valid inequality for a certain binary knapsack polyhedron. CS correspond to dual variables of the set-partitioning model of a special 1D cutting-stock problem. Some CS can be constructed by (data-dependent) dual-feasible functions ((D)DFFs). We discuss the relation of CS to DFFs: CS assume that at most one copy of each object can appear in a combination, whereas DFFs allow several copies. The literature has investigated the so-called extremal maximal DFFs (EMDFFs) which should provide very strong CS. Analogously, we introduce the notions of maximal CS (MCS) and extremal maximal CS (EMCS) and show that EMDFFs do not necessarily produce (E)MCS. We propose fast greedy methods to “maximize” a given CS. Using the fact that EMCS define facets of the binary knapsack polyhedron, we use lifted cover inequalities as EMCS. For higher-dimensional orthogonal packing, we propose a Sequential LP (SLP) method over the set of CS and investigate its convergence. Numerical results are presented.

Details

Original languageEnglish
Pages (from-to)505-542
Number of pages38
JournalOR spectrum : quantitative approaches in management
Volume35
Issue number2
Publication statusPublished - 2013
Peer-reviewedYes

External IDs

Scopus 84874018255
researchoutputwizard legacy.publication#55963

Keywords

DFG Classification of Subject Areas according to Review Boards

Subject groups, research areas, subject areas according to Destatis

Keywords

  • packing problem, conservative scales