The authors of this papers presented an exact and heuristic approach. This paper is in the field of OR. It is about transporting resources in hard to reach places with multiple landing places. Defs:
The authors wanted to have an exact method to solve this problem and compare it to heuristics, using artificial data and Dutch navy data.
The algorithm is NP-hard.
In the paper priority levels are introduced for different kind of items and groups of items which should be transported together.
To model this problem we use a time-space network. Every node has a location in time and space. All the loading and unloading is done in a single timeslot.
Related problems are:
The authors made an ILP-formulation. A better option is to use a route. Every connector has a route. This makes it possible to disregard certain routes, which makes it possibl
There are tasks and agents who perform the tasks. You can make a table out of this with cells of the table containing the cost for the given task and agent. The total cost will be the sum of the costs of the tasks being performed by the given agent. We can make a tree out of this by having the an agent on every depth level of the tree. This agent chooses its task on every level. This way we do not need to go through all the possibilities.
If we have a set of routes $R$ we will look at a subset $R'\subset R$. We are only adding routes to this subset that will improve the objective.
It uses a subproblem like branch and bound. And for every subproblem we use column generation.
They constructed instances from