In this paper, we present several primal heuristics which we implemented in the branch-and-price solver GCG based on the SCIP framework. This involves new heuristics as well as heuristics from the literature that make use of the reformulation yielded by the Dantzig-Wolfe decomposition. We give short descriptions of those heuristics and briefly discuss computational results. Furthermore, we give...

We investigate the problem of simultaneously determining the location of facilities and the design of vehicle routes to serve customer demands under vehicle and facility capacity restrictions. We present a set-partitioning-based formulation of the problem and study the relationship between this formulation and the graph-based formulations that have been used in previous studies of this problem....

This paper presents the results of developing a branch and price algorithm and an ejection chain method for nurse rostering problems. The approach is general enough to be able to apply it to a wide range of benchmark nurse rostering instances. The majority of the instances are real world applications. They have been collected from a variety of sources including industrial collaborators, other r...

In this presentation, we consider the Split Delivery Vehicle Routing Problem with Time Windows (SDVRPTW) in which the delivery to a customer can be split between any number of vehicles. This problem has not been extensively studied in the literature. The main contribution of this paper is a Branch and Price approach for solving the SDVRPTW without imposing restrictions on the split delivery opt...

We apply the methodology Branch-and-Price Guided Search to a real-world maritime inventory routing problem. Computational experiments demonstrate that the approach quickly produces solutions that are near-optimal and of better quality than those produced by a state-of-the-art, commercial integer programming solver when given much more time. We also develop local search schemes to further reduce...

Staff rostering is a major challenge in the service sector, where exploitation costs are essentially made up of staffing costs. Searching for an optimum has direct economic returns but the rosters must satisfy numerous legal constraints. This paper presents work on an exact approach using branch-and-price methods on a concrete situation. We develop three MILP models and extend them with valid i...

The problem of identifying the (dynamic) team structures and team behaviors from the observed activities of multiple agents is called Multi-Agent Plan Recognition (MAPR). We extend a recent formalization of this problem to accommodate a compact, partially ordered, multi-agent plan language, as well as complex plan execution models – particularly plan abandonment and activity interleaving. We ad...

In this study we introduce the regenerator location problem in flexible optical networks (RLP-FON). With a given traffic demand, RLP-FON tries to solve the regenerator placement, routing, bandwidth allocation and modulation selection problems jointly to satisfy data transfer demands with the minimum number of regenerators. We propose a novel branch and price algorithm for this challenging probl...

When combinatorial bidding is permitted in auctions, such as the proposed FCC auction #31, the resulting full valuations and winner-determination problem can be computationally challenging. We present a branch-and-price algorithm based on a set-packing formulation originally proposed by Dietrich and Forrest (2002). This formulation has a variable for every possible combination of winning bids f...

Airline rescheduling is a relatively new field in airline Operations Research but increasing amounts of traffic will make disturbances to the original schedule more frequent and more severe. Thus, the need to address the various problems arising from this situation with systematic, cost-efficient approaches is becoming more urgent. One such problem is crew rescheduling where after a disturbance...