Assignment problem

About: Assignment problem is a research topic. Over the lifetime, 7588 publications have been published within this topic receiving 172820 citations. The topic is also known as: marriage problem.

Finding a robust assignment of flights to gates at Amsterdam Airport Schiphol

Abstract: In this paper we investigate the gate assignment problem as it appears at Amsterdam Airport Schiphol (AAS). Currently, the gate planners spend many hours on adjusting the automatically generated planning during the day of operation to make it proof against small deviations from the schedule. To alleviate this problem, we aim at finding a robust solution, given the planned arrivals and departures for the next day. We present a completely new integer linear programming formulation that is based on so-called gate plans. Each gate plan consists of a subset of the flights that can be assigned to a single gate of the corresponding type; gates with identical characteristics are aggregated in gate types. The gate assignment problem then boils down to selecting the best subset of gate plans such that each flight belongs to one selected gate plan, and such that the number of selected gate plans for a certain type of gate is equal to the number of gates of this type. In the first phase, we solve the LP-relaxation through column generation, and we describe specific features to find a very good solution to the ILP quickly. This solution is then handed to the planners at AAS in order to assign gate plans to physical gates. This consists of a number of relatively small problems that can be solved by hand and in which additional operational constraints can be incorporated. We also present the possibility of directly assigning flights to physical gates using the column generation formulation, where we then take into account other criteria as well. Computational results with real-life data provided by AAS are promising and indicate that the algorithm is able to solve real-life instances within rather small running times.

Scheduling Sport Tournaments using Constraint Logic Programming.

Abstract: We tackle the problem of scheduling the matches of a round robin tournament for a sport league. We formally define the problem, state its computational complexity, and present a solution algorithm using a two-step approach. The first step is the creation of a tournament pattern and is based on known graph-theoretic results. The second one is an assignment problem and it is solved using a constraint-based depth-first branch and bound procedure that assigns actual teams to numbers in the pattern. The procedure is implemented using the finite domain library of the constraint logic programming language \eclipse. Experimental results show that, in practical cases, the optimal solution of the assignment problem (which is not necessarily optimal for the overall problem) can be found in reasonable time, despite the fact that the problem is NP-complete. In addition, a local search procedure has been developed in order to provide, when necessary, an approximate solution in shorter time.

Low-power state assignment techniques for finite state machines

Abstract: The problem of minimizing the power consumption in synchronous sequential circuits is explored in this paper. We present a general theoretical framework to solve the state assignment problem for Finite State Machines (FSMs). In this framework, the problem has been separated in two different tasks. First, we define heuristic techniques to visit the State Transition Graph (STG) and thus to assign a priority to the symbolic states. Second, we define encoding techniques to assign binary codes to the symbolic states to reduce the switching activity of state registers. Based on this approach, we propose five power-oriented state assignment algorithms. These techniques have been applied to MCNC benchmark circuits and the experimental results have shown an average reduction in transition activity (power) of 8.56% (5.35%) over well-known low-power state encoding schemes.