3.3.1 Importer module
The importer module accounts for the rational behaviors of importers in international iron ore trade. Each importer has a given purchasing budget for iron ore imports. Since importers are price takers and the iron ores from different exporters are imperfect substitute, each importer maximizes its consumption utility by choosing appropriate proportions of iron ores from different exporters within the budget constraint. For an importer , its utility maximization can be described as follows: