Research Article
Mathematical Model and Simulated Annealing Algorithm for the Two-Dimensional Loading Heterogeneous Fixed Fleet Vehicle Routing Problem
Table 2
Model sets, parameters, and variables.
| Indexes/sets | | | Set of vertices from the depot () to customers () | | Set of vehicles | | Set of stages in which a customer can be served by a vehicle | | Set of items demanded by all customers. Each customer demands a set |
| Parameters | | | Number of customers | | Distance from each customer to each customer | | Number of vehicles | | Weight capacity of each vehicle | | Length of the loading surface of each vehicle | | Width of the loading surface of each vehicle | | Fixed cost of each vehicle | | Variable cost of each vehicle | | Number of items demanded by each customer | | Total weight demanded by each customer | | Length of each item | | Width of each item |
| Variables | | | Binary variable that indicates whether vehicle goes directly from vertex to vertex in stage () or not | | Continuous variable that indicates the -coordinate of the front-left corner of item on the vehicle loading surface | | Continuous variable that indicates the -coordinate of the front-left corner of item in the vehicle loading surface | | Binary variable that indicates whether item is loaded into vehicle or not | | Binary variable that indicates whether item is loaded behind item or not | | Binary variable that indicates whether item is loaded in front of item or not | | Binary variable that indicates whether item is loaded on the left side of item or not | | Binary variable that indicates whether item is loaded on the right side of item or not |
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