Optimization of the drayage problem using exact methods

Abstract

Major liner shipping companies offer pre-and end-haulage as part of a door-to-door service. However, pre-and end-haulage is one of the major bottlenecks in liner shipping due to the lack of coordination between the customers often leading to inefficiency. In this paper we apply techniques from vehicle routing problems to the problem of pre-and end-haulage of containers, and test it on data from a major liner shipping company. The paper contains several versions of the problem such as multiple empty container depots, and balancing the empty container depot levels and their influence on the cost is shown. Finding a set of optimal vehicle routes allowing these combinations is NP-hard. However, by exploring the fact that the number of possible routes in the considered case is quite limited, we show that the model can be solved within a minute by using column enumeration. Alternative constraints and problem formulations are considered. Computational results are reported on real-life data from a major liner shipping company.

A set-covering formulation for a drayage problem with single and double container loads

“…However, this is left for future developments, as the set-covering model can solve instances with up to 503 containers in less than 3 h. This is already more than enough to cater the needs of the medium-size carrier originating this study, which handles about 150 containers in peak days: the set-covering model could effectively support the routing decision process even if the carrier container volumes would triplicate. This result is also interesting in the context of the literature where the stay-with modus operandi is adopted (see Table 1): it would seem that the corresponding approaches can only handle a smaller number of containers (e.g., up to 200 containers in the heuristics of Imai et al (2007) and Caris and Janssens (2009), and up to 308 in the exact approach of Reinhardt et al (2016). Finally, we remark that the effect of the new policy looks particularly beneficial for the instances of class E and J, where we obtain the largest percentage improvements of this paper with respect to the current policy.…”

Intermodal Container Routing: Integrating Long-Haul Routing and Local Drayage Decisions

“…The vehicle fleet is often considered homogeneous; only two papers discuss a heterogeneous fleet [31,32]. Multiple vehicle depots can be included [33][34][35][36][37][38]. Moreover, to cope with imbalances between demand and supply of containers at different locations, the allocation of empty containers can be modelled [32][33][34][35][36][37][38][39][40].…”

“…The objective is to minimise total trucking and rail costs (37) for the delivery of customer requests. Constraints (38)-(41) relate to (2)-(5) of the intermodal routing problem, where one of the feasible services for each request must be selected (with for each feasible service, one feasible pickup and one feasible delivery task).…”

All-optical control of unipolar pulse generation in a resonant medium with nonlinear field coupling

“…In particular, this property can be an advantage if one wants to control the ultrafast charge motion in the pump-probe experiments. Specifically, unipolar pulses can efficiently deliver a kinetic momentum to the charged particles in order to control their motion, for instance, to ionize the atoms or ions in the medium [5][6][7] or to measure the quantum dynamics of electron and ionic wavepackets [8][9][10][11]. Unipolar pulses can efficiently accelerate the charge particles and thus be used for producing coherent beams for particle injectors and charge-particle accelerating devices [12,13].…”