Human and Ecological Risk Assessment: An International Journal

ABSTRACT This article examines the location-allocation of emergency service facilities as aresearch subject. The research presents the setup of the single allocation set cov-ering location-allocation models for emergency service facilities under strong timeconstraints, in view of the shortage of hub & spoke network bypass. The article alsopresentsanextensiontothesingleallocationsetcoveringlocation-allocationmodel(SASCP) and the SASCP model with bypass constraints ( γ -SASCP) for emergencyservice facilities under large-scale emergency requirements. For the two models,an improved genetic algorithm was designed and the two models were respectivelysolved, with the effectiveness of the algorithm verified by a specific example. Theimpacts of change of parameters such as time discount rate, maximum time con-straints, and bypass ratio on the model’s results are compared and analyzed, basedon solved results by the specific example. Key Words: single allocation, set covering, bypass constraints, location-allocation,genetic algorithm.