Scientific Program > Plenary Talks



 Monday, July 10, 9:30-10:30 (Room KC07)

Chairman: Prof. Daniele Vigo (University of Bologna)

"Network Design in Liner Shipping" (video)

Speaker: Prof. David Pisinger

Full Professor, Technical University of Denmark

Department of Management Engineering

The shipping industry is responsible for around 2.2% of the CO2 emission in the world, and a substantial part of the NOx and SOx emission. Decreasing freight rates and tight regulations for emission makes it difficult to operate liner shipping economically viable. It is therefore necessary to frequently redesign the network to meet customer demands while minimizing the operational costs.

Given a fleet of container vessels and a set of demands to transport, the liner shipping network design problem asks to design a set of scheduled routes, deploy vessels of appropriate size to the routes and decide the speed on each leg, such that all demands can be transported within some pre-defined time-limits. Real-life instances may involve 20.000 demands and 500 vessels pushing the limits of solvers.

In this talk we give an overview of recent solution methods, spanning from branch-and-cut methods, to matheuristics and backbone-based methods. Results from the LINER-LIB benchmark suite will be reported. In the end of the presentation, some parallels will be drawn to the related line planning problem in public transportation.




Wednesday, July 12, 11:30-12:30 (Room KC07)

Chairman: Prof. Stefan Irnich (Chair of Logistics Management, Johannes Gutenberg University Mainz)

 "Branch-price-and-cut for Vehicle Routing: Recent Advances" (video)

Speaker: Prof. Guy Desaulniers

Director, GERAD

Full Professor, Polytechnique Montreal

Department of Mathematics and Industrial Engineering

Branch-price-and-cut (BPC) is the leading methodology for solving many vehicle routing problems exactly such as the capacitated vehicle routing problem, the vehicle routing problem with time windows, and the split delivery vehicle routing problem with time windows, to name just a few. It consists of a column generation algorithm embedded in a branch-and-cut framework and involves, thus, several algorithmic components that often need to be specialized for the problem considered. In this talk, we review the main ingredients that are part of the most recent BPC algorithms. Among others, we discuss the ng-route pricing algorithm, the route enumeration procedure, and the non-robust cuts that are defined directly on the master problem variables. We highlight certain tradeoffs that need to be addressed when designing a BPC algorithm. Also, to illustrate the effectiveness of some BPC algorithms, we report recent computational results obtained for different vehicle routing problems. To conclude, we present current challenges that arise from complex vehicle routing problems.

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