Research Article

Modeling the Multicommodity Multimodal Routing Problem with Schedule-Based Services and Carbon Dioxide Emission Costs

Table 3

Symbols in the optimization model and their representations.

IndicesRepresentation

Index of the terminals, and .
Index of the transportation service, and .
()Directed arc from terminal to terminal , and .

SetsRepresentation

Set of rail services on , and .
Set of road services on , and .
Set of the transportation services on , , and .
Set of the predecessor terminals to terminal , and .
Set of the successor terminals to terminal , and .

ParametersRepresentation

Operation start time of rail service at terminal .
Operation cutoff time of rail service at terminal .
Scheduled arrival time of rail service at terminal .
Scheduled departure time of service from terminal .
Available capacity of rail service at terminal when being operated on , unit: TEU.
Transportation distance of service on , unit: km.
Transportation time of service on , unit: h.
Transportation costs of moving commodity on by service , unit: ¥.
Unit costs of loading/unloading operation of service , unit: ¥/TEU.
Unit inventory costs of rail service, unit: ¥/TEU-h.
Additional charges for picking up the unit commodity from shipper at a rail terminal by rail service at origin, unit: ¥/TEU.
Additional charges for delivering the unit commodity from rail terminal to receiver by rail service at destination, unit: ¥/TEU.
A parameter indicating whether origin pickup service is needed for commodity . If the service is needed, ; otherwise, .
A parameter indicating whether destination delivery service is needed for commodity . If the service is needed, ; otherwise, .
Unit carbon dioxide emissions costs, unit: ¥/g.
Emission factor for carbon dioxide of service , unit: g/TEU-km.
A large positive number.

Decision variablesRepresentation

0-1 decision variable. If commodity is moved from terminal to terminal by service , ; otherwise, .
Arrival time of commodity at terminal .
Charged inventory time of commodity at terminal before being moved on by rail service , unit: h.