3 research outputs found
Tackling Dynamic Vehicle Routing Problem with Time Windows by means of Ant Colony System
The Dynamic Vehicle Routing Problem with Time Windows (DVRPTW) is an
extension of the well-known Vehicle Routing Problem (VRP), which takes into
account the dynamic nature of the problem. This aspect requires the vehicle
routes to be updated in an ongoing manner as new customer requests arrive in
the system and must be incorporated into an evolving schedule during the
working day. Besides the vehicle capacity constraint involved in the classical
VRP, DVRPTW considers in addition time windows, which are able to better
capture real-world situations. Despite this, so far, few studies have focused
on tackling this problem of greater practical importance. To this end, this
study devises for the resolution of DVRPTW, an ant colony optimization based
algorithm, which resorts to a joint solution construction mechanism, able to
construct in parallel the vehicle routes. This method is coupled with a local
search procedure, aimed to further improve the solutions built by ants, and
with an insertion heuristics, which tries to reduce the number of vehicles used
to service the available customers. The experiments indicate that the proposed
algorithm is competitive and effective, and on DVRPTW instances with a higher
dynamicity level, it is able to yield better results compared to existing
ant-based approaches.Comment: 10 pages, 2 figure
SOM-Guided Evolutionary Search for Solving MinMax Multiple-TSP
Multiple-TSP, also abbreviated in the literature as mTSP, is an extension of
the Traveling Salesman Problem that lies at the core of many variants of the
Vehicle Routing problem of great practical importance. The current paper
develops and experiments with Self Organizing Maps, Evolutionary Algorithms and
Ant Colony Systems to tackle the MinMax formulation of the Single-Depot
Multiple-TSP. Hybridization between the neural network approach and the two
meta-heuristics shows to bring significant improvements, outperforming results
reported in the literature on a set of problem instances taken from TSPLIB.Comment: 8 pages, 12 figures, 2 tables, CEC 201