Multigraph Modeling for Urban Distribution of Emergency Commodities with Semisoft Time Windows under Uncertainty

Abstract

In this paper, we studied a stochastic bi-objective mathematical model for effective and reliable rescue operations in multigraph network. The problem is addressed by a two-stage stochastic nonlinear mixed-integer program where the reliability of routes is explicitly traded-off with total weighted completion time. The underlying transportation network is able to keep a group of multiattribute parallel arcs between every pair of nodes. By this, the proposed model should consider the routing decision in logistic planning along with the path selection in an uncertain condition. The first stage of the model concerns with the vehicle routing decisions which is not involved with random parameters; besides, the second stage of the model involves with the departure time at each demand node and path finding decisions after observation of random vectors in the first stage considering a finite number of scenarios. To efficiently solve the presented model, an enhanced nondominated sorting genetic algorithm II (NSGA-II) is proposed. The effectiveness of the introduced method is then evaluated by conducting several numerical examples. The results implied the high performance of our method in comparison to the standard NSGA-II. In further analyses, we investigated the beneficiary of using multigraph setting and showed the applicability of the proposed model using a real transportation case.

Constraints on Transport of Injured Victims after the Earthquake for Disaster Victims’ Evacuation Model Development: A Phenomenological Study

“…DVE usually uses land vehicles such as ambulances. However, damage to road infrastructure has affected the speed of vehicles in evacuation [40]. The types of modes that can be used are also more limited because some of the larger ambulance sizes are difficult to maneuver in the narrowed road conditions caused by the disaster.…”

“…Sometimes, the nurse on duty uses an ambulance to transport two victims, but the level of emergency for victims is different; this was also revealed in the study. This is a positive thing when the number of ambulances is limited because ambulance capacity affects the number of victims evacuated [41], but ambulances must be used to evacuate victims according to their type and capacity [40].…”

Integrated Design of Emergency Medical and Material Distribution Networks During the Epidemic Outbreak Period

“…Long et al [17] developed a multi-stage siting-distribution model for emergency materials. Tikani et al [18] Established a two-stage stochastic nonlinear mixed integer programming model for emergency materials distribution considering time window and other factors. Wang et al [19] established a multi-regional emergency materials coordination and dispatching model, taking into account factors such as differences in the supply of emergency materials between different regions and uneven reserves of materials, but did not consider the location of emergency materials distribution points.…”