Robust solution is defined as a solution which has "both feasibility robustness and optimality robustness; Feasibility robustness means that the solution should remain feasible for (almost) all possible values of uncertain parameters and flexibility degrees of constraints and optimality robustness means that the value of objective function for the solution should remain close to optimal value or have minimum (undesirable) deviation from the optimal value for (almost) all possible values of uncertain parameters and flexibility degrees on target value of goals".3
As fuzzy mathematical programming is categorized into Possibilistic programming and Flexible programming, ROFP also can be classified into:4
The first category is used to deal with imprecise input parameters in optimization problems while the second one is employed to cope with flexible constraints and goals. Also, the last category is capable to handle both uncertain parameters and flexibility in goals and constraints.
From another point of view, it can be said that different ROFP models developed in the literature can be classified in three categories according to degree of conservatism against uncertainty. These categories include:5
Hard worst case ROFP has the most conservative nature among ROFP methods since it provides maximum safety or immunity against uncertainty. Ignoring the chance of infeasibility, this method immunizes the solution for being infeasible for all possible values of uncertain parameters. Regarding the optimality robustness, this method minimizes the worst possible value of objective function (min-max logic). On the other hand, Soft worst case ROFP method behaves similar to hard worst case method regarding optimality robustness, however does not satisfy the constraints in their extreme worst case. Lastly, realistic method establishes a reasonable trade-off between the robustness, the cost of robustness and other objectives such as improving the average system performance (cost-benefit logic).
ROFP is successfully implemented in different practical application areas such as the following ones.
Pishvaee, M. S.; Razmi, J.; Torabi, S. A. (2012-11-01). "Robust possibilistic programming for socially responsible supply chain network design: A new approach". Fuzzy Sets and Systems. Theme : Operational Research. 206: 1–20. doi:10.1016/j.fss.2012.04.010. /wiki/Doi_(identifier) ↩
Pishvaee, Mir Saman; Fazli Khalaf, Mohamadreza (2016-01-01). "Novel robust fuzzy mathematical programming methods". Applied Mathematical Modelling. 40 (1): 407–418. doi:10.1016/j.apm.2015.04.054. https://doi.org/10.1016%2Fj.apm.2015.04.054 ↩
Zahiri, Behzad; Tavakkoli-Moghaddam, Reza; Pishvaee, Mir Saman (2014-08-01). "A robust possibilistic programming approach to multi-period location–allocation of organ transplant centers under uncertainty". Computers & Industrial Engineering. 74: 139–148. doi:10.1016/j.cie.2014.05.008. /wiki/Doi_(identifier) ↩
Mousazadeh, M.; Torabi, S. A.; Zahiri, B. (2015-11-02). "A robust possibilistic programming approach for pharmaceutical supply chain network design". Computers & Chemical Engineering. 82: 115–128. doi:10.1016/j.compchemeng.2015.06.008. /wiki/Doi_(identifier) ↩
Bairamzadeh, Samira; Pishvaee, Mir Saman; Saidi-Mehrabad, Mohammad (2015-12-22). "Multiobjective Robust Possibilistic Programming Approach to Sustainable Bioethanol Supply Chain Design under Multiple Uncertainties". Industrial & Engineering Chemistry Research. 55 (1): 237–256. doi:10.1021/acs.iecr.5b02875. /wiki/Doi_(identifier) ↩
Zhou, Y.; Li, Y.P.; Huang, G.H. (2015-12-15). "A robust possibilistic mixed-integer programming method for planning municipal electric power systems". International Journal of Electrical Power & Energy Systems. 73: 757–772. Bibcode:2015IJEPE..73..757Z. doi:10.1016/j.ijepes.2015.06.009. /wiki/Bibcode_(identifier) ↩
Xu, Ye; Huang, Guohe (2015-10-15). "Development of an Improved Fuzzy Robust Chance-Constrained Programming Model for Air Quality Management". Environmental Modeling & Assessment. 20 (5): 535–548. Bibcode:2015EMdAs..20..535X. doi:10.1007/s10666-014-9441-3. /wiki/Bibcode_(identifier) ↩