We address the tactical fixed job scheduling problem with spread-time constraints. In such a problem, there are a fixed number of classes of machines and a fixed number of groups of jobs. Jobs of the same group can only be processed by machines of a given set of classes. All jobs have their fixed start and end times. Each machine is associated with a cost according to its machine class. Machine...

The sports team realignment problem can be modelled as k-way equipartition: given a complete graph Kn = (V, E), with edge weight ce on each edge, partition the vertices V into k divisions that have exactly S vertices, so as to minimize the total weight of the edges that have both endpoints in the same division. In this paper, we discuss solving k-way equipartition problem using branch-and-price...

The maximum weight independent set problem (MWISP) is one of the most well-known and wellstudied problems in combinatorial optimization. This paper presents a novel approach to solve MWISP exactly by decomposing the original graph into vertex-induced sub-graphs. The approach solves MWISP for the original graph by solving MWISP on the sub-graphs in order to generate columns for a branch-and-pric...

Many rostering methods first create shifts from some given staffing levels, and after that create rosters from the set of created shifts. Although such a method has some nice properties, it also has some bad ones. In this paper we outline a method that creates rosters directly from staffing levels. We use a Branch-and-Price (B&P) method to solve this rostering problem and compare it to an ILP f...

The Traveling Tournament Problem is a sports timetabling problem requiring production of a minimum distance double round robin tournament for a group of n teams. Even small instances of this problem seem to be very difficult to solve. In this paper, we present the first provably optimal solution for an instance of 8 teams. The solution methodology is a parallel implementation of a branch and pr...

In several countries, home care is provided for certain citizens living at home. The long-term home care scheduling problem is to generate work plans such that a high quality of service is maintained, the work hours of the employees are respected, and the overall cost is kept as low as possible. We propose a branchand-price algorithm for the long-term home care scheduling problem. The pricing p...

We consider the problem of dispatching technicians to service/repair geographically distributed equipment. This problem can be cast as a vehicle routing problem with time windows, where customers expect fast response and small delays. Estimates of the service time, however, can be subject to a significant amount of uncertainty due to misdiagnosis of the reason for failure or surprises during re...

Despite recent successful real-world deployments of Stackelberg Security Games (SSGs), scale-up remains a fundamental challenge in this field. The latest techniques do not scale-up to domains where multiple defenders must coordinate time-dependent joint activities. To address this challenge, this paper presents two branch-and-price algorithms for solving SSGs, SMARTO and SMARTH , with three nov...

We consider the Weighted Vertex Coloring Problem (WVCP), in which a positive weight is associated to each vertex of a graph. In WVCP, one is required to assign a color to each vertex in such a way that colors on adjacent vertices are di erent, and the objective is to minimize the sum of the costs of the colors used, where the cost of each color is given by the maximum weight of the vertices ass...

We consider planning of freight train classification at hump yards using integer programming. The problem involves the formation of departing freight trains from arriving trains subject to scheduling and capacity constraints. To increase yard capacity, we allow the temporary storage of early freight cars on specific mixed-usage tracks. The problem has previously been modeled using a direct inte...