Table 1 Parameter definition.

From: Multi-objective integrated optimization study of prefabricated building projects introducing sustainable levels

Parameters

Parameter definition

Parameters

Parameter definition

T

Total project duration

\({\omega _2}\)

Environmental goal weighting factor

I

The set of processes on a critical line in the network plan

\({\omega _3}\)

Social goal weighting factor

\({t_{si}}\)

Minimum duration of process i

\({H_i}\)

Total workdays of workers to complete process i

\({t_i}\)

Actual duration of process i

\({C_{hi}}\)

Per capita respiratory carbon emission factor

\({t_{li}}\)

Maximum duration of process i

\({M_i}\)

Consumption of the first material to complete process i

\({t_{ni}}\)

Normal duration of process i

\({C_{mj}}\)

Carbon emission factor of the jth material

\({C_Z}\)

Direct cost of process i

\({U_i}\)

Completion of the first energy consumption to complete process i

\({C_J}\)

Indirect costs of process i

\({C_{sk}}\)

Carbon emission factor of the kth energy source

\({C_B}\)

Variable cost of early or late completion of works

\({E_A}\)

Total emissions of all air pollutants

\({C_T}\)

Carbon cost of process i

\({E_D}\)

Total emissions of all solid waste

\({C_{ni}}\)

Direct costs for the normal duration of process i

\({E_W}\)

Total volume of all sewage discharges

\({\alpha _{1i}}\)

Incremental marginal cost factor

\(E{I_i}\)

Environmental level index of process i

\({\alpha _{2i}}\)

Overhead costs per day for process i

\(E{I_{i\max }}\)

Limit values of environmental level of the process

\({\alpha _{3i}}\)

Variable cost factor

\(W{I_i}\)

Number of jobs provided by completed processes

\({\alpha _{4i}}\)

Carbon tax rate for construction industry

K

Sustainability level index

\({\omega _1}\)

Economic target weighting factor

\({C_{Ti}}\)

Carbon cost of process i