IF-EM: An interval-parameter fuzzy linear programming model for environment-oriented evacuation planning under uncertainty.

The processes and factors involved in evacuation activities are associated with a variety of uncertainties, posing major challenges to evacuation planners. This study represents an attempt to employ inexact optimization techniques for addressing uncertainties in evacuation practices. In this study, an interval-parameter fuzzy evacuation management (IF-EM) model is developed for supporting environment-oriented evacuation management under uncertainty. Through IF-EM, uncertainties in the model's stipulations and coefficients which are expressed as fuzzy sets and interval numbers can be directly communicated into the optimization process, greatly enhancing the robustness of the optimization system. The model is then applied to a case study and solved through a two-step interactive algorithm. A number of evacuation schemes can be generated by adjusting decision variables within their solution intervals according to projected planning conditions, reflecting various decision policies and a compromise between system optimality and stability. The relationships among vehicle allocation pattern, evacuation time, system satisfaction level, and system reliability level can be effectively reflected, facilitating more in-depth analyses of interactions among system efficiency, environmental protection, and economic cost. Results from the case study suggest that the proposed IF-EM model is applicable to practical evacuation problems that are associated with uncertainties and complexities. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]