# Transportation and Reserve of Emergency Medical Supplies during Public Health Events
## 3 Materials and Methods
### Model of Forecast Demand for Emergency Medical Materials  
Emergency medical materials generally refer to the urgently needed medical materials for the treatment of infected patients and injured people after disasters when various emergencies occur [28]. Emergency medical materials are one of the urgently needed materials that need emergency input after emergencies. Taking as an example the need for emergency medical materials in COVID-19, the types of emergency medical materials are, but are not limited to, the following categories [29]:  
* Medical supplies, such as medical masks, protective clothing, goggles, gloves, disinfectant, thermometers, medicines, and first aid kits;
* Rescue equipment: mainly construction machinery, excavators, bulldozers, loaders, dump trucks, tankers, generator sets, and medical waste treatment equipment;
* Communication equipment: including radio communication equipment, wired communication equipment, etc.;
* Living security materials, mainly tents, folding beds, sleeping bags, inflatable mattresses, folding tables and chairs, portable stoves, emergency lights, folding buckets, plastic buckets, garbage bags, and food.  
To predict the demand for emergency medical materials, it is necessary to predict the number of people according to Section 3.1, combined with the urgent needs of various groups of people for consumable medical materials in the early stages of the epidemic. Due to the lack of uniform and effective personnel classification methods and standards, there are many problems in large-scale population evacuation. Considering the complexity of the amount of emergency materials needed by different people in a single day in the SEIRD model, we set the model by directly defining the emergency medical materials group \(\theta\)[30]. In view of the ambiguity of the actual observation of the susceptible population (\(S\)) and the exposed population (\(E\)), we classified these two groups as the susceptible population (\(S\)) and drew the conclusion that \(S=(N-I-R-D)\). Therefore, the hypothesis is established as shown in Table 1.  
According to the epidemic experience, the daily demand for each infected person is \(3\theta I\). The daily demand of each susceptible person is \(2\theta(N-I-R-D)\). The demand of each recovered person in a single day is \(\theta R\). At the same time, the daily consumption index and the proportion of daily demand for different types of infection were formulated. Through calculation, the daily consumption of various items is obtained: In a single day the demand for medical surgical masks weighing approximately 18 grams by the cured population is 2. The number of disposable gloves with a weight of approximately 4 grams is three sets. The 75 grams of goggles are required every day. The demand for disinfection products weighing approximately 27 grams is 30 mL (containing alcohol and antibacterial hand gel). Disposable gloves and goggles are mainly used to isolate patients and infected persons during the epidemic, while alcohol and disinfectant are used to treat or care for patients, which are the most commonly used drugs in hospitals. The total weight is 150 g, and the daily emergency medical supplies required by a single person in kilograms are 0.15, that is, the set \(\theta=0.15\), so the daily total demand for susceptible people is \(0.3(N-I-R-D)\), the daily total demand for infected people is \(0.45\)\(I\) and the daily total demand for cured people is \(0.15\)\(R\).