Channel Choice#
Supplier Channel Choice#
As POLARIS is being implemented regionally, a subset of the nationally synthesized establishments is used. For a given region, a percentage of the external FIS establishments within the U.S. and a representation of the main ports of entry. These sets of establishments are used to create the trade partnerships between agents. A threshold of suppliers is used as an input to define the maximum number of suppliers for each receiver. There are two model types that can be used within POLARIS from the receiver perspective: (a) the current implemented model which involves random sampling from the selected suppliers’ subset based on the IO make-use tables, this approach is highly dependent on the selection procedure of the external suppliers. Selecting those suppliers with production capabilities in accordance with the total tonnage shipped from these suppliers’ zones to the study region can yield a match between the simulated and observed CFS shipping distance distributions. However, this approach does not consider matching the production and consumption capacities of the selected pair. (b) A multi-objective optimization model which has been developed (in progress) that considers the heterogeneity in goods’ values, reduction in total costs of orders, increase in selected supplier ratings based on collected survey data, and reduction in the gap between the observed and simulated freight flows. This model is developed to build an optimized calibrated supplier choice which accounts for the production capabilities of each supplier.
Carrier Channel Choice#
Based on the results of the asset choice and supplier selection models, the relevant carrier of goods between each pair of supplier and receiver is selected. For the receivers and suppliers that own their own fleet, their fleets are used to transport the goods. For the others, carriers are selected from the synthesized establishments that belong to the transportation sector with preference to proximity to the supplier location. Work in progress for a more elaborate model for carrier selection is underway.
Important
Please refer to the the following papers for more details:
Stinson, M., and A. (Kouros) Mohammadian. Introducing CRISTAL: A Model of Collaborative, Informed, Strategic Trade Agents with Logistics. Transportation Research Interdisciplinary Perspectives, Vol. 13, 2022, p. 100539. https://doi.org/10.1016/j.trip.2022.100539.
Pourabdollahi, Z. An Agent-Based Freight Transportation Modeling Framework. University of Illionis at Chicago, 2015.