A B S T R A C TIn the international trade cargo logistics system, the port choice of the shipper is seen to depend not only on transportation costs, but also on the value of the cargoes being shipped. In many previous studies, researchers have assumed that the ultimate aim of shippers when making port choices was to minimize inland freight costs. They then used that assumption to develop mathematical programming models for port choices. In practice, however, when making decisions about port choices, shippers always focus on total logistics costs. In other words, shippers not only aim to minimize the inland freight costs but also consider the frequency of ship callings. Thus, in this paper, a mathematical programming model for port choice of shippers, which not only considers inland freight costs but also takes into account the frequency of ship callings, is proposed and tested using a Taiwanese port case. The results show that the model proposed in this paper can be used to explain the actual port choice behaviors of Taiwanese shippers accurately.
Container terminals help countries to sustain their economic development. Improving the operational efficiency in a container terminal is important. In past research, genetic algorithms (GAs) have been widely used to cope with seaside operational problems, including the berth allocation problem (BAP) and quay crane assignment problem (QCAP) individually or simultaneously. However, most GA approaches in past studies were dedicated to generate time-invariant QC assignment that does not adjust QCs assigned to a ship. This may underutilize available QC capacity. In this research, three hybrid GAs (HGAs) have been proposed to deal with the dynamic and discrete BAP (DDBAP) and the dynamic QCAP (DQCAP) simultaneously. The three HGAs supports variable QC assignment in which QCs assigned to a ship can be further adjusted. The three HGAs employ the same crossover operator but a different mutation operator and a two-stage procedure is used. In the first stage, these HGAs can generate a BAP solution and a QCAP solution that is time-invariant. The time-invariant QC assignment solution is then further transformed into a variable one in the second stage. Experiments have been conducted to investigate the effects of the three HGA and the results showed that these HGAs outperformed traditional GAs in terms of fitness value. In particular, the HGA3 with Thoros mutation operator had the best performance.
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