Keywords: Shipping Optimization, Inventory-Routing, Min-Cost, Multi-Sources, Mutli-Sinks
I am looking for a freelancer to formulate an optimization problem from the Liquefied Natural Gas (LNG) shipping industry mathematically and within a solver such as CPLEX.
Some details about the context:
In the world of LNG, the user of the model, has committed to several pick-up obligations and to several delivery obligations. On the pick-up side, the following information is available: the name of all the export terminals, where the user committed to pick-up cargo. The volume that he committed to pick-up at each terminal and a time frame within a year (e.g. week 10-14) when he committed to pick up the cargo. The same on the delivery side: name of each import terminal, delivery volume at each import terminal, and time-frame for delivery. The distance between each export terminal and each import terminal is given. Further, the user must specify the number of tankers available to him, the capacity of each tanker, the tanker's location and the time when the tanker is at that location. Moreover, the fuel consumption and the daily charter rate for the tanker are known.
The model should optimize and decide which cargo is to be picked-up by which tanker at which port in which order, to satisfy all pick-up and delivery obligations - while minimizing costs as the objective.
Some details about the problem:
- Objective function is to minimize costs. Costs = (distance * fuel consumption) + (distance/speed * daily charter rate) + canal passage fee.
- Multiple sources, each with volume for export in given time-frame
- Multiple sinks, each with volume for import in given time-frame
-> The user picks e.g. 5 export points, puts in how much volume needs to be picked-up at each port, and in which time-frame for pick-up. The user further specifies e.g. 4 import ports, how much needs to be delivered where and by which time frame. If the total export volume is not equal the total import volume, additional LNG volumes can be sourced from an artificial market source or to an artificial market sink.
- Each source is connected to each sink on an direct bi-directional edge. As for the route between the port of Doha, Qatar to Kochi, India, the choice of route is clear and therefore only one edge exists, for other routes (e.g. from Sabine Pass, USA to Yokohama, Japan) two or even more routes edges may exists to account for different routing alternatives such as the Panama Canal or the Suez Canal.
- To use an edge a ship must be in place at the source of this edge. The volume of transportation on the edge is limited to the total volume of the ships available at the source of the edge.
Surely, I forgot a few more details about the problem's constraints - however, you got an impression if you came through reading this far. Lets have a more detailed conversation if you are feeling confident that you can both formulate this problem mathematically and also to formulate it within a solver such as CPLEX.
In your offer, please indicate how you would engage/solve this problem!