Operational forest harvest scheduling optimisation: a mathematical model and solution strategy

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dc.contributor.advisor Professor David Ryan en
dc.contributor.advisor Dr Chris Goulding en
dc.contributor.author Mitchell, Stuart Anthony en
dc.date.accessioned 2007-09-06T01:37:20Z en
dc.date.available 2007-09-06T01:37:20Z en
dc.date.issued 2004 en
dc.identifier.citation Thesis (PhD--Engineering Science)--University of Auckland, 2004. en
dc.identifier.uri http://hdl.handle.net/2292/1761 en
dc.description.abstract This thesis describes the Operational Harvest Scheduling (OHS) problem and develops an algorithm that solves instances of the problem. The solution to an OHS problem is an Operational Harvest Schedule (OHS). An OHS: ² assigns forest harvesting crews to locations within a forest in the short-term (4-8 weeks); ² instructs crews to harvest specific log-types and allocates these log-types to customers; ² maximises profitability while meeting customer demand. The OHS problem is modelled as a Mixed Integer Linear Program (MILP). The formulation given in this thesis differs significantly from previous literature, especially with regard to the construction of the problem variables. With this novel formulation, the problem can be solved using techniques developed in previous work on aircraft crew scheduling optimisation (Ryan 1992). These techniques include constraint branching and column generation. The concept of relaxed integer solutions is introduced. A traditional integer solution to the OHS problem will require harvesting crews to move between harvesting locations at the end of a week. However, a relaxed integer solution allows crews to move at any time during a week. This concept allows my OHS model to more effectively model the practical problem. The OHS model is formulated for New Zealand and Australian commercial forestry operations,though the model could be applied to other intensively managed production forests. Three case studies are developed for two companies. These case studies show improvements in profitability over manual solution methods and a significant improvement in the ability to meet demand restrictions. The optimised solutions increased profit (revenue less harvesting and transportation costs) by between 3-7%, while decreasing the total value of excess or shortfall logs by between 15-86%. en
dc.language.iso en en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof PhD Thesis - University of Auckland en
dc.relation.isreferencedby UoA1451006 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.subject Optimization en
dc.subject Forestry en
dc.title Operational forest harvest scheduling optimisation: a mathematical model and solution strategy en
dc.type Thesis en
thesis.degree.discipline Engineering Science en
thesis.degree.grantor The University of Auckland en
thesis.degree.level Doctoral en
thesis.degree.name PhD en
dc.subject.marsden Fields of Research::230000 Mathematical Sciences en
dc.subject.marsden Fields of Research::290000 Engineering and Technology en
dc.rights.holder Copyright: The author en
pubs.local.anzsrc 09 - Engineering en
pubs.org-id Faculty of Engineering en

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