@TECHREPORT\{IMM2007-05342,
    author       = "S. G. Christensen and D. M. Rous{\o}e",
    title        = "Container loading with multi-drop constraints",
    year         = "2007",
    keywords     = "Packing; Container loading; Multi-drop; Load bearing strength; Tree-search",
    number       = "",
    series       = "IMM-Technical Report-2007-15",
    institution  = "Informatics and Mathematical Modelling, Technical University of Denmark, {DTU}",
    address      = "Richard Petersens Plads, Building 321, {DK-}2800 Kgs. Lyngby",
    type         = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/5342-full.html",
    abstract     = "In this paper an algorithm for the container loading problem (CLP) with multi-drop constraints is presented. When adding multi-drop constraints we demand, that the relevant boxes must be available, without rearranging others, when each drop-off point is reached. To make the solutions feasible in the real world, it is further demanded that all boxes are placed in a feasible manner with respect to load bearing strength and with proper support from below. This makes it possible to load consignments originating from builder merchants.

A heuristic based on a tree search framework is proposed. It uses greedy solutions to evaluate each choice taken. To make the framework more generic, a dynamic breadth is proposed. Based on problem characteristics and the time limit imposed, it will choose the breadth of the tree, making sure that the time is utilised most profitable.

The algorithm is tested on new real world data from a Danish company distributing construction products. For the solutions to these problems to be feasible in a real world setting both multi-drop- and load bearing strength constraints are essential. The obtained results show, that the proposed model and algorithm are able to solve the new real world problems in fractions of a second. Furthermore, results obtained on benchmark problems indicate that the algorithm performs comparable with other more specialised methods."
}