An Interval MiniMax Regret Programming (IMMRP) method is
designed by Yong and Huang [33] for the planning of municipal
SWM system under uncertainty. Such method improves on the
existing interval programming and minimax regret analysis
methods by allowing uncertainties, presented as both intervals
and random variables of the optimization process. The IMMRP
takes into account the economic impacts of all possible scenarios
without any assumption on their probabilities. The developed
method is applied to a case study of long-term SWM planning
under uncertainty. The uncertainty arises in waste-generation rate,
and it is modeled by means of random variables; on the other
hand, some random events can only be quantified as discrete
intervals, leading to the concept of Interval Random Variable (IRV).
The decision maker does not know the probabilistic distribution of
the IRV. Based on this method, if the waste-flow level equals the
waste-generation rate, the system pays regular costs, leading to
minimum cost and regret levels, otherwise an excess regret is
generated due to the violation of the available resources.
A computational analysis is performed with multiple scenarios
associated with different cost and risk levels. The results show that
G. Ghiani et al. / Computers & Operations Research 44 (2014) 22–32 27
Author's personal copy
the proposed approach is helpful for planning policies in the
context of waste management under a variety of uncertainties