| In this study, an interval-parameter two-stage mixed-integer linear programming (ITMILP) method is developed for supporting long-term planning of waste management systems under uncertainty. The method improves upon the existing two-stage programming and mixed-integer linear programming techniques by incorporating uncertainties expressed as not only probability density functions but also discrete intervals within a general optimization framework. It can be used for analyzing various policy scenarios that are associated with different levels of economic penalties when the promised targets are violated. Optimal solutions obtained through the model can provide an effective linkage between the predefined environmental policies and the associated economic implications (e.g., losses and/or penalties caused by improper policies). The ITMILP model can be transformed into two submodels, which correspond to the lower and upper bounds of the objective-function value. The binary-variable solutions represent the decisions of waste-management-facility expansion, and the continuous ones are related to decisions of waste-flow allocation. The interval solutions can help decision-makers to obtain multiple decision alternatives, as well as provide bases for further analyses of tradeoffs between waste-management cost and system-failure risk. (Abstract shortened by UMI.)... |
