Abstract
In this paper we present the solution to a weekly log-truck scheduling problem (LTSP) integrating the routing and scheduling of trucks where all goods are transported in full truckloads. We must take into account pick-up and delivery requirements, multiple products, inventory levels, and lunch breaks. The objective is to minimize the overall transportation cost including wait times and the empty and loaded distance traveled. Our solution is based on a two-phase approach. The first phase involves an integer linear program that determines the destinations of full truckloads. The second phase uses an implicit integer linear program based on an arc formulation to ensure that the trucks are routed and scheduled at a minimum cost. Experiments have been conducted using Cplex 12.4.0, and almost all instances were solved within six hours with a reasonable gap.
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Notes
FPInnovation is a private, not-for-profit R&D organization whose mission is to improve Canadian forestry operations.
Abbreviations
- B :
-
Set of all bases
- c l :
-
Cost of waiting time of a log-loader per unit of time
- c a :
-
Cost associated with arc a (empty driven arcs and truck waiting times)
- t l :
-
Loading time of one shipment
- t u :
-
Unloading time of one shipment
- H :
-
Optimization horizon
- \(T_{a}^{s}\) :
-
Start time associated with arc a
- \(T_{a}^{e}\) :
-
End time associated with arc a
- K fm :
-
Number of full truckloads to be delivered from forest area f to wood mill m
- L bfm :
-
Set of loaded-trip arcs linking forest area f and wood mill m and associated with base b
- L b :
-
⋃ f∈F ⋃ m∈M L bfm , set of loaded-trip arcs associated with base b
- A +(s b ):
-
Set of exiting arcs from the source node s b associated with base b
- A −(t b ):
-
Set of entering arcs into the sink node t b associated with base b
- A +(i):
-
Set of exiting arcs from node i
- A −(i):
-
Set of entering arcs into node i
- \(A_{bf}^{T}\) :
-
Set of loading arcs (a b ) loading at forest area f and associated with base b, such that their start times \(T_{a_{b}}^{s} \in[T,T+t^{l} [\), T≤H
- \(A_{bm}^{T}\) :
-
Set of unloading arcs (a b ) unloading at wood mill m and associated with base b, such that their start times \(T_{a_{b}}^{s} \in [T,T+t^{u} [\), T≤H
- C bf :
-
Set of loading arcs associated with forest area f and base b
- C b :
-
⋃ f∈F C bf , set of loading arcs associated with base b
- D b :
-
Set of unloading arcs associated with base b
- E b :
-
Set of empty driven arcs associated with base b
- W b :
-
Set of truck waiting arcs associated with base b
- N b :
-
Set of nodes associated with base b
- V b :
-
Number of trucks for base b
- A :
-
Set of all arcs.
- \(x_{a_{b}}\) :
-
Number of trucks that follow arc a b ∈A
- \(t_{f}^{min}\) :
-
Start time of log-loader associated with forest area f
- \(t_{f}^{max}\) :
-
End time of log-loader associated with forest area f
References
Andersson, G., Flisberg, P., Lidén, B., & Rönnqvist, M. (2008). RuttOpt—a decision support system for routing of logging trucks. Canadian Journal of Forest Research, 38, 1784–1796.
Bramel, J., & Simchi-Levi, D. (1997). On the effectiveness of set covering formulations for the vehicle routing problem with time windows. Operational Research, 45(2), 295–301.
Bredström, D., & Rönnqvist, M. (2008). Combined vehicle routing and scheduling with temporal precedence and synchronization constraints. European Journal of Operational Research, 191(1), 19–31.
D’Amours, S., Rönnqvist, M., & Weintraub, A. (2008). Using operational research for supply chain planning in the forest products industry. INFOR. Information Systems and Operational Research, 46(4), 265–281.
El Hachemi, N., Gendreau, M., & Rousseau, L.-M. (2011). A hybrid constraint programming approach to the log-truck scheduling problem. Annals of Operations Research, 184(1), 163–178.
El Hachemi, N., Gendreau, M., & Rousseau, L.-M. (2013). A heuristic to solve the synchronized log-truck scheduling problem. Computers & Operations Research, 40(3), 666–673.
Eveborn, P., Flisberg, P., & Rönnqvist, M. (2006). Laps care—an operational system for staff planning of home care. European Journal of Operational Research, 171(3), 962–976.
Eveborn, P., Rönnqvist, M., Einarsdóttir, H., Eklund, M., Lidén, K., & Almroth, M. (2009). Operations research improves quality and efficiency in home care. Interfaces, 39(1), 18–34.
Flisberg, P., Lidén, B., & Rönnqvist, M. (2008). A hybrid method based on linear programming and tabu search for routing of logging trucks. Computers & Operations Research, 36(4), 1122–1144.
Gronalt, M., & Hirsch, P. (2007). Log-truck scheduling with tabu search strategy. Metaheuristics, 39, 65–88.
Linnainmaa, S., Savalo, J., & Jokinen, O. E. P. (1995). A knowledge based system for wood procurement management. Paper presented at the 7th Annual Conference on Artificial Intelligence, Montreal
Murphy, G. (2003). Reducing trucks on the road through optimal route scheduling and shared log transport services. Southern Journal of Applied Forestry, 27(3), 198–205.
Palmgren, M., Rönnqvist, M., & Värbrand, P. (2003). A solution approach for log truck scheduling based on composite pricing and branch and bound. International Transactions in Operational Research, 10, 433–447.
Palmgren, M., Rönnqvist, M., & Värbrand, P. (2004). A near-exact method for solving the log-truck scheduling problem. International Transactions in Operational Research, 11, 447–464.
Rey, P. A., Muñoz, J. A., & Weintraub, A. (2010). A column generation model for truck routing in the Chilean forest industry. INFOR. Information Systems and Operational Research, 47(3), 215–221.
Rönnqvist, M. (2003). Optimization in forestry. Mathematical Programming, 97, 267–284.
Rönnqvist, M., Sahlin, H., & Carlsson, D. (1998). Operative planning and dispatching of forestry transportation. Report LiTH-MAT-R-1998-18, Linköping University, Linköping, Sweden
Rönnqvist, M., & Ryan, D. (1995). Solving truck dispatch problems in real time. In Proceedings of the 31st annual conference of the operational research society of New Zealand, Wellington, New Zealand, 31 August–1 September 1995 (pp. 165–172). Auckland: Operational Research Society of New Zealand.
Toth, P., & Vigo, D. (2001). The vehicle routing problem. Philadelphia: Society for Industrial and Applied Mathematics.
Weintraub, A., Epstein, R., Morales, R., Seron, J., & Traverso, P. (1996). A truck scheduling system improves efficiency in the forest industries. Interfaces, 26(4), 1–12.
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El Hachemi, N., El Hallaoui, I., Gendreau, M. et al. Flow-based integer linear programs to solve the weekly log-truck scheduling problem. Ann Oper Res 232, 87–97 (2015). https://doi.org/10.1007/s10479-014-1527-4
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DOI: https://doi.org/10.1007/s10479-014-1527-4