In this paper we describe a two-stage optimization model for determining robust rolling stock circulations for passenger trains. Here robustness means that the rolling stock circulations can better deal with large disruptions of the railway system. The two-stage optimization model is formulated as a large Mixed-Integer Linear Programming model. We first use Benders decomposition to determine op...

The cell suppression problem (CSP) is one of the most widely applied methods for tabular data protection. Given a set of primary cells to be protected, CSP aims at finding a set of secondary cells to be additionally removed to guarantee that estimates of values of primary cells fall out of a predefined protection interval. From a computational point of view, CSP is very challenging even for tab...

This paper presents a method that combines Benders decomposition and column generation to solve the multi-activity tour scheduling problem. The Benders decomposition approach iterates between a master problem that links daily shifts with tour patterns and a set of daily subproblems that assign work activities and breaks to the shifts. Due to its structure, the master problem is solved by column...

The purpose of this paper is to introduce an integrated and specialized approach tackling a challenging issue, known as “Last-mile Transportation”. This which classified in terms the decision-making level at tactical level, model operational application processes prominent businesses online commerce developed countries, while it has attracted little attention from operation-research aspect. sin...

We study the problem of interdicting the arcs in a network in order to maximize the shortest s–t path length. “Interdiction” is an attack on an arc that destroys the arc or increases its effective length; there is a limited interdiction budget. We formulate this bilevel, max–min problem as a mixed-integer program (MIP), which can be solved directly, but we develop more efficient decomposition a...

Most local search algorithms are “perturbative”, incrementally moving from a search state to a neighbouring state while performing noisy hill-climbing. An alternative form of local search is “constructive”, repeatedly building partial solutions using greedy or other heuristics. Both forms have been combined with constraint propagation, and they can be hybridised with each other by perturbing pa...

Supply chain models describe the activities carried out in the process industry. They are used to design and operate complex sequences of tasks that transform raw materials and deliver final products to markets. Many optimization models have been developed for supply chain planning because they offer the possibility of finding strategies that lead to greater economic benefits. The traditional m...

A recent paper by Heinz and Beck (CPAIOR 2012) found that mixed integer software has become competitive with or superior to logic-based Benders decomposition for the solution of facility assignment and scheduling problems. Their implementation of Benders differs, however, from that described in the literature they cite and therefore results in much slower performance than previously reported. W...