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Model II: Medical Resource Is Limited

5.5 Conclusions

In this study, we rely on a discrete time-space network to describe medical resources allocation problem when an unexpected influenza is outbreak. We formulate the problem as a multi-stage integer programming model with time-varying demand based on SEIR diffusion rule. The three main differences that distinguish this work from the past literature are presented as follows.

Firstly, the model proposed in this study addresses a time-series demand that is forecasted in match of the course of influenza diffusion. The model couples a multi-stage integer programming for optimal allocation of medical resources with a proactive forecasting mechanism cultivated from influenza diffusion dynamics. The rationale that medical resources allocated in early periods take effect in subduing the spread of influenza and thus impact demand in later periods has been for the first time incorporated into our model.

Secondly, the computational results based on a numerical example show that the proposed model is superior to the general measures in both terms of cost reduction and medical resources control. Our model can reduce the total operation cost of medical resources allocation and may get influenza diffusion in control earlier than general measures.

Last but not least, medical resources allocation problem has always been formu- lated as vehicle routing problem (VRP), or vehicle routing problem with time win- dows (VRPTW) in precious literatures, which includes many sub-tour constraints and is difficult to solve. In this study, we decompose medical resources allocation problem into several mutually correlated sub-problems, and solve them systemati- cally in the same decision scheme subsequently. Therefore, the proposed method is more suitable for an actual decision-making support.

The next research steps of this study incorporate a more realistic influenza dif- fusion model including features such as subdivision of the population by risk group and disease stage. It can also include the cross area diffusion between two or more geographic areas, and the incorporation of purchase lead time of medical resources.

In addition, the utilization of multiple resources in model is another important topic for the further research.

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Integrated Optimization Model for Two-Level Epidemic-Logistics Network

As mentioned in the above chapters, the demand of emergency resource is usually uncertain and varies quickly in anti-bioterrorism system. With the consideration of emergency resources allocated to the epidemic areas in the early rescue cycles will affect the demand in the following periods, we construct an integrated and dynamic optimization model with time-varying demand for the emergency logistics network based on the epidemic diffusion rule. The heuristic algorithm coupled with ‘DDE23 tool’ in MATLAB is adopted to solve the optimization model, and the application of the model as well as a short sensitivity analysis of the key parameters in the time- varying demand forecast model is presented by a numerical example. The win-win emergency rescue effect is achieved by such an optimization model. Thus, it can provides some guidelines for decision makers when coping with emergency rescue problem with uncertain demand, and offers an excellent reference when issues are pertinent to bioterrorism.