Applications – OR and Management Sciences

Robust Airline Schedule Planning: Minimizing Propagated Delay in an Integrated Routing and Crewing Framework

Categories Airline Optimization Tags , ,

To retain a degree of tractability, the airline scheduling problem has traditionally been sequentially decomposed into various stages (eg. schedule generation, fleet assignment, aircraft routing, and crew pairing), with the decisions from one stage imposed upon the decision making process in subsequent stages. Whilst this approach greatly simpli es the solution process, it unfortunately fails to … Read more

Sequencing and Scheduling in Coil Coating with Shuttles

Categories (Mixed) Integer Linear Programming, Graphs and Matroids, Production and Logistics Tags , , , , , ,

We consider a complex planning problem in integrated steel production. A sequence of coils of sheet metal needs to be color coated in consecutive stages. Di erent coil geometries and changes of coatings may necessitate time-consuming setup work. In most coating stages one can choose between two parallel color tanks in order to reduce setup times. … Read more

New Lower Bounds for the Vehicle Routing Problem with Simultaneous Pickup and Delivery

Categories Branch and Cut Algorithms, Production and Logistics, Transportation Tags , ,

This work deals with the Vehicle Routing Problem with Simultaneous Pickup and Delivery (VRPSPD). We propose undirected and directed two-commodity flow formulations, which are based on the one developed by Baldacci, Hadjiconstantinou and Mingozzi for the Capacitated Vehicle Routing Problem. These new formulations are theoretically compared with the one-commodity flow formulation proposed by Dell’Amico, Righini … Read more

Benders decomposition for the hop-constrainted survivable network design problem

Categories Branch and Cut Algorithms, Telecommunications

Given a graph with nonnegative edge weights and a set of pairs of nodes Q, we study the problem of constructing a minimum weight set of edges so that the induced subgraph contains at least K edge-disjoint paths containing at most L edges between each pair in Q. Using the layered representation introduced by Gouveia, … Read more

A branch-and-price algorithm for multi-mode resource leveling

Categories (Mixed) Integer Linear Programming, Scheduling Tags , ,

Resource leveling is a variant of resource-constrained project scheduling in which a non-regular objective function, the resource availability cost, is to be minimized. We present a branch-and-price approach together with a new heuristic to solve the more general turnaround scheduling problem. Besides precedence and resource constraints, also availability periods and multiple modes per job have … Read more

Exactly solving a Two-level Hierarchical Location Problem with modular node capacities

Categories (Mixed) Integer Linear Programming, Telecommunications Tags , , , ,

In many telecommunication networks a given set of client nodes must be served by different sets of facilities, providing different services and having different capabilities, which must be located and dimensioned in the design phase. Network topology must be designed as well, by assigning clients to facilities and facilities to higher level entities, when necessary. … Read more

A MATHEMATICAL PROGRAMMING MODEL FOR THE DESIGN OF AIRPORT CONFIGURATIONS

Categories Airline Optimization, Transportation Tags , ,

A mathematical programming model for assessing the design of an optimal airport topology is presented herein. It takes into account the efficient and safe taxiing of aircraft on the ground. We balance a set of conflicting factors that depend directly on aircraft trajectories on the ground, such as the number of arriving and departing flights … Read more

Optimal location of family homes for dual career couples

Categories Applications - OR and Management Sciences, Facility Planning and Design, Multi-Criteria Optimization Tags , , , ,

The number of dual-career couples with children is growing fast. These couples face various challenging problems of organizing their lifes, in particular connected with childcare and time-management. As a typical example we study one of the difficult decision problems of a dual career couple from the point of view of operations research with a particular … Read more

Chemotherapy operations planning and scheduling

Categories Applications - OR and Management Sciences, Scheduling Tags , , ,

Chemotherapy operations planning and scheduling in oncology clinics is a complex problem due to several factors such as the cyclic nature of chemotherapy treatment plans, the high variability in resource requirements (treatment time, nurse time, pharmacy time) and the multiple clinic resources involved. Treatment plans are made by oncologists for each patient according to existing … Read more

A concave optimization-based approach for sparse portfolio selection

Categories Constrained Nonlinear Optimization, Finance and Economics, Stochastic Approaches Tags , , ,

This paper considers a portfolio selection problem in which portfolios with minimum number of active assets are sought. This problem is motivated by the need of inducing sparsity on the selected portfolio to reduce transaction costs, complexity of portfolio management, and instability of the solution. The resulting problem is a difficult combinatorial problem. We propose … Read more