Green Vehicle Routing and Scheduling Optimization of Ship Steel Distribution Center Based on Improved Intelligent Water Drop Algorithms

Table 1

	The objective function includes fixed use cost, fuel and carbon emission cost, and driver’s salary
	Set of nodes (including distribution centers)
	Shipyard assembly
	Vehicle assembly
	Distance of arc segment
	It means the weight of steel that the distribution center needs to deliver to shipyard
	Delivery time window allowed by shipyard
	The amount of fuel consumed per unit distance for no-load vehicles
	Additional fuel consumption per unit distance for vehicles carrying goods per unit weight
	The time when vehicle arrives at shipyard
	The loading and unloading service time of vehicle at shipyard
	The travel time of vehicle from node to node
	The total amount of cargo to be delivered by the shipyard after the vehicle arrives at the shipyard to complete the loading and unloading task
	The fixed use cost of vehicles
	Labour remuneration paid to drivers per unit time
	Cost per unit of fuel and carbon emissions
EP	Penalty coefficient for early arrival of vehicles
LP	Penalty coefficient for vehicle lateness
PC	Penalty cost for vehicle failure to arrive on time