Research On Combinatorial Optimization Problem Of Multi-routes Intermodal Transport Network

Nowadays, China has been in the new normal, as one of the basic industry of national economy, the industrial structure and supply ability of traditional transportation industry can’t satisfy the continued growth of social demand. So solving the sustainable development of transportation industry, especially the cargo transportation industry, directly relates to the sustainable development of social economy. As an advanced, efficient and eco-friendly transportation mode, intermodal transport develops maturely in developed countries but still be in growth stage in China because of the long-term market system constraints. Developing intermodal transport needs planning the route and transport mode based on the existing route network, thus to transport goods at the lowest cost within the customer request. The traditional problem only considered the final transportation time, but not included the arriving time and departure time for transport tools at relay nodes. Also it is possible that goods from different start points need to be transported in the same network, but previous studies only plan one route for single goods, so this paper puts forward a new solution in this aspect.Based on the traditional model, this paper plans the routes and mode for different goods in the same network and builds the combinational optimization model of transportation route and mode in intermodal transport network with multi-routes, making the transport cost, transferring cost, time penalty cost and transport time as objective function. Considering the transport tools are limited to arriving time and leaving time, so this paper sets time window constraint for each node. Meanwhile, considering that different goods may use the same transport tool at the same path, so the total volume should satisfy the capacity constraint. So it will be more realistic that bringing above constraints into traditional optimal problem, which helps carriers planning scientifically to reduce the cost and improve the customer satisfaction.Aiming at the problem and math model in the paper, the improved dynamic adaptive ant colony algorithm is designed and multi-population ants are used to search path at the same time, also the roulette is used to improve the randomness, combining the elite ant and maxmin ant strategy to quicken the rate of convergence to avoid falling into the local optimum. At last, the algorithm is tested by different cases to demonstrate the effectiveness of the improved ant colony algorithm, the key parameters is analyzed and reference values are put forward. The paper provides an effective method for combinational optimization problem of transportation route and mode in intermodal transport network.