The Job Shop is a well-known model for scheduling problems, which are captured as a shop in which a set of jobs need to be completed that consist of operations that can be performed by machines of the shop. Operations take time and machines can only perform one operation at a time. This leads to a scheduling problem to decide what operation should be performed at what time, typically to complete all jobs as soon as possible. Different kinds of additional constraints may apply, such as ordering and dependencies between operations, deadlines or setup times for machines.
We have explored solutions to job shop (in particular flow shop) problems using constraint graph. A constraint graph is weighted graph structure in which vertices represent operations and weighted edges represent constraints between the start times of the operations it connects in a valid schedule. Scheduling decisions can be captured by adding edges to the graph. Longest path and positive cycle algorithms such as Bellman-Ford can be used to study schedulability and determine as-soon-as-possible schedules.
With the framework one can explore greedy list scheduling heuristics, backtracking branch-and-bound algorithms, or multi-objective heuristics.
Schedule methods have been applied to the xCPS system and in collaboration with Canon Production Printing to investigate scheduling of production printers.
Selected Publications
2019
Parametric Scheduler Characterization Journal Article
In: ACM Trans. Embed. Comput. Syst., vol. 18, no. 5s, 2019, ISSN: 1539-9087.
2018
Optimization of product flows in flexible manufacturing systems PhD Thesis
Electrical Engineering, 2018, ISBN: 978-94-6380-165-2, (Proefschrift).
Parametric Critical Path Analysis for Event Networks With Minimal and Maximal Time Lags Journal Article
In: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, vol. 37, no. 11, pp. 2697-2708, 2018.
A Heuristic for Variable Re-Entrant Scheduling Problems Proceedings Article
In: 2018 21st Euromicro Conference on Digital System Design (DSD), pp. 336-341, 2018.
2017
Scheduling and variation-aware design of self-re-entrant flowshops PhD Thesis
Electrical Engineering, 2017, ISBN: 978-90-386-4372-4, (Proefschrift).
Online Scheduling of 2-Re-Entrant Flexible Manufacturing Systems Journal Article
In: ACM Trans. Embed. Comput. Syst., vol. 16, no. 5s, 2017, ISSN: 1539-9087.
2016
Online heuristic for the Multi-Objective Generalized traveling salesman problem Proceedings Article
In: 2016 Design, Automation & Test in Europe Conference & Exhibition (DATE), pp. 822-825, 2016.
A Fast Estimator of Performance with Respect to the Design Parameters of Self Re-Entrant Flowshops Proceedings Article
In: 2016 Euromicro Conference on Digital System Design (DSD), pp. 215-221, 2016.
2015
A re-entrant flowshop heuristic for online scheduling of the paper path in a large scale printer Proceedings Article
In: 2015 Design, Automation & Test in Europe Conference & Exhibition (DATE), pp. 573-578, 2015.