TITLE: Modelling, Methods and Mathematics: Three Faces of Integer Programming

SPEAKER:  Natashia Boland

ABSTRACT:

Mining and water are two areas of national importance to Australia, the former for its economic importance and the latter for its growing scarcity. An optimization problem arising in each of these settings will be considered. In mining, the problem concerns scheduling maintenance on transport and logistics equipment in a coal export supply chain so as to minimize the impact of maintenance activities on the throughput of the system. In water, the problem is how best to manage water allocated to the environment under Australia's regulatory framework. These applications highlight the need to solve integer programs with multiple objectives. We will present new methods for biobjective integer programming that exploit the power of modern MIP solvers. The resulting methods deduce the efficient frontier in a computationally effective way. One of the features exploited in these methods is the ability of solvers to make use of high quality feasible solutions. Alternating projection algorithms have been of increasing interest as heuristics for MIPs, and more broadly for discrete optimization problems. However, little is known about the theoretical properties of such algorithms in these settings. We mention some recent advances in this direction, and demonstrate algorithmic improvements.