Contributed Session Thu.2.MA 042

Thursday, 13:15 - 14:45 h, Room: MA 042

Cluster 13: Logistics, traffic, and transportation [...]

Synchronization and collision avoidance


Chair: Torsten Joachim Gellert



Thursday, 13:15 - 13:40 h, Room: MA 042, Talk 1

F. Javier Martin-Campo
On solving the aircraft collision avoidance problem for the ATM by horizontal maneuvers. A ranked mutiobjective MINLO problem

Coauthors: Antonio Alonso-Ayuso, Laureano F. Escudero


A mixed 0-1 nonlinear optimization approach is presented to solve the aircraft collision avoidance problem for the Air Traffic Management. Given the flight plans configuration, the problem consists of deciding a strategy such that every conflict situation is avoided. For this aim, we consider two possible maneuvers: velocity and angle changes, in a high nonconvex mixed integer nonlinear optimization (MINLO) approach that is based on a geometric construction. In order to determine which maneuvers will be followed, a ranked multiobjective approach is presented optimizing one of them by appending to it the constraint that satisfies the optimal objective function value of the other one with higher rank allowing an epsilon violation, such that the optimal solution of the higher rank objective can be used as a hot start for optimizing the other one. Some preliminary computational results will be presented by using a state-of-the-art nonconvex MINLO engine at each iteration, where a MINLO submodel is solved.



Thursday, 13:45 - 14:10 h, Room: MA 042, Talk 2

Nils-Hassan Quttineh
Aircraft mission planning

Coauthors: Kaj Holmberg, Torbjörn Larsson, Kristian Lundberg


We present a military aircraft mission planning problem, where the problem is to find time efficient flight paths for a given aircraft fleet that should attack a number of ground targets. Due to the nature of the attack, two aircraft need to rendezvous at the target, that is, they need to be synchronized in both space and time. Each target is associated with multiple attack options, and there may also be precedence constraints between targets, limiting the order of the attacks. The objective is to maximize the outcome of the entire attack, while also minimizing the mission timespan.



Thursday, 14:15 - 14:40 h, Room: MA 042, Talk 3

Torsten Joachim Gellert
Scheduling multiple cranes on a shared pathway

Coauthor: Rolf H. Möhring


In many logistics applications, transport requests are conducted in parallel by several vehicles moving along a fixed shared pathway. Examples include cranes mounted on a common rail, like gantry cranes loading and unloading containers in intermodal transportation, or forklifts moving along a narrow passageway in large warehouses.

In theory, assigning transport requests to the vehicles of such systems and scheduling their execution amounts to finding k tours on a common line, where tours may never cross each other in time - dynamic collision constraints need to be respected. The goal is to minimize the
makespan for a given set of transport requests.
This problem contains other challenging tasks like partitioning jobs and assigning starting times.

We present a model capturing the core challenges in transport planning problems of this type and prove NP-hardness for the problem.
The structural properties can be used to formulate a mixed integer program with starting time variables, but without any assignment of jobs to vehicles. Furthermore, we show some special cases where an optimal solution can be found in polynomial time.


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