Optimal Transportation Scheduling of Prefabricated Components Based on Improved Hybrid Differential Firefly Algorithm

Table 1

Parameters for the model.

Parameters	Definition
i	Number of transport vehicles, i = 1,2,3, ..., M
j	Number of the construction sites, j = 1,2,3, ..., N
a	Number of the prefabricated component factories, a = 1,2,3, ..., A
k	k^th delivery service
Daj	Distance between factory a and construction site j
Kj	Number of times construction site j needs to be transported
Ka	Number of vehicles allocated by factory a
(ETj, LTj)	Time window constraint set by construction site j
STajk	Departure time of the k^th transport vehicle sent from prefabricated component factory a to construction site j
LTajk	Loading time of the k^th transport vehicle sent from prefabricated component factory a to construction site j
UTajk	Unloading time of the k^th transport vehicle sent from prefabricated component factory a to construction site j
DTajk	Departure time of the k^th transport vehicle sent from prefabricated component factory a to construction site j
RTajk	Return time of the k^th transport vehicle sent from prefabricated component factory a to construction site j
t, t′	Transportation time and return time from prefabricated component factory a to construction site j
λ1, λ2, λ3, λ4, λ5	λ1 is the unit fixed cost, λ2 is the unit delivery cost when transported with a full load, λ3 is the unit delivery cost of empty return, λ4 is the cost coefficient of unit waiting time for unloading, and λ5 is the unit penalty cost coefficient
	Calculation coefficient of the k^th delivery vehicle of factory a waiting for unloading at consumer j
	Calculation coefficient of k^th delivery service of consumer j waiting for factory a