This paper introduced a novel model for the transportation problem of a consolidation network where direct shipment,
cross-docking and shipment through milk run trips are used simultaneously in order to send the loads from the suppliers to the
customers. Because of the model’s complexity, a heuristic approach
based on harmony search and simulated annealing was proposed to
S.D. Hosseini et al. / Journal of Manufacturing Systems 33 (2014) 567–577 577
solve the problem, which uses a special solution structure scheme
that reduces the need for physical memory and can therefore deal
with larger problem instances. The proposed HS-SA algorithm and
GAMS/CPLEX were tested on 4 problems sets (totally 40 instances)
for verification. The computational results and comparisons of their
outputs were also presented. It was verified that our approach not
only outperforms GAMS/CPLEX solutions and results in reduction
of total transportation cost in the network, but also its computational time requirement is noticeably less than that of GAMS/CPLEX
especially for larger size problem instances.
It was the first time that milk run transportation system was
utilized in the cross-docking network and, therefore, some other
studies can be carried out to survey the role that this type of transportation system can play in flexibility and cost and delivery time
reduction in cross-docking networks. In addition, delivery and pickup time window can be considered at the cross-docks in order to
minimize the total transportation time or satisfy the time horizon
constraint of the entire transportation operation. Moreover, some
assumptions of the mathematical modelling could be relaxed, for
example, the problem could be formulated alternatively to determinetheloadamounttobesentfromthesupplierstothecustomers
according to their demand or to provide the possibility of using
vehicles with different capacities in the model.