Ship Scheduling In Tramp Shipping Based On Choice Behaviors Of Shippers And The Spatial/Temporal Transport Demand

Tramp shipping is the main transportation mode for dry bulk cargoes such as grain,iron ore,coal.Compared with the liner,it is obviously complexity,so it is always the hot in the seaborne transportation.In tramp shipping market,the choice of shippers and the spatial and temporal transport demand determine carriers’ decision-makings of task choices and ship routings.In view of spatial and temporal transport demand changes,most previous studies only consider the seasonal fluctuations for one cargo kind.From the transport seasonal fluctuation and cargo direction,the paper intends to distinguish the spatial and temporal transport demand change characteristics of different cargo kinds.Based on the Clarkson statistics,we calculate the season fluctuation coefficient of grain,iron ore and coal separately.And then calculate cargo transport demand on different segments on different quarters,combining with total demands of three cargo kinds on different segments.We simulate the carriers’ choice spot,and optimize the scheduling schemes on each segment.For the shippers’ choice inertia,previous studies only consider that the changes of some factors,such as loading and unloading time window,speed,freight rate fluctuations and climate,affect the transportation revenues at the single of carriers.They don’ t consider the carriers’ behaviors,especially the choice inertia.In this paper,we see the shippers in different segments as an integrated shipper,and take its choice inertias as the market shares on the segments.We think carrier’ s size and the number of the previous offered services on the segment decide the current market shares.And then based on the transport demands on segments on different quarters,we calculate the transport carriers may obtain on each segment by Logit model.Based on the research methods about spatial and temporal transport demand and shippers’ choice inertia,from the view of a carrier,this paper divides the whole sipping planning period into different time windows,and design a tramp shipping scheduling model with the objective of maximizing long-term benefits.The freight is set as an endogenous variable,which relates with the transport distance and seasonal fluctuations.The determination including the being shipped cargoes,the sailing routs and the used ships.At last,design Genetic algorithm to solve the model,and using Pacific Tramp Shipping market as an example a numerical test is implemented.