A two-dimensional extension of Allen's temporal logic as an intelligent support for the solution of packing problems

Abstract

Inland vessels move goods along canals and rivers and they visit ports. Due to tides on the rivers, the vessels make use of locks to enter ports or canals. From a port management point of view, a fast access to and from the port and high utilisation of a lock are important objectives. The policy to access the lock works as follows. Vessels wait in front of the lock. A port administrator assigns a place in the lock based on the knowledge of the vessels’ dimensions. As such, there is no FIFO-discipline, but a ‘group-FIFO’-discipline, i.e. if n vessels are allowed to the lock, they are the first n vessels in the arrival queue. A heuristic algorithm is formulated for the placement of vessels in the lock. This algorithm supports the decision where to place the vessel in the lock, aiming to place as many as possible vessels from the arrival queue. The paper describes the implementation of the heuristic which is based on a two-dimensional extension of Allen’s temporal logic.