An Analysis of the Distribution of Hospital Centers with Passive Defense Approach to Hazard Management using Neural Network (Case Study: Tabriz City)

Introduction
Hospital as one of the critical parts of the city should be considered in terms of passive defense to hazard management. Since the city of Tabriz has a large supply of medical services, it is necessary that the hospitals in this city be investigated and suitable parts from the perspective of passive defense are presented. In the present study, using 13 effective criteria and using neural network method, we investigated the position of hospitals in Tabriz city. The criteria include: distance from fire stations, distance from industrial and military centers, distance from parks and urban green spaces, distance from health centers, distance from main roads, population density, distance from faults, distance from riverside, Distance from training centers, distance from business premises, distance from warehouse and urban facilities, distance from fuel centers and dispersal and access radius of hospitals. The layers were first straightened and standardized in the Arc map, then using Neural Networks method using MATLAB software. To achieve the research goals, 104 educational points were introduced to the system. The results of the study indicate the status of hospitals in terms of non-operating defense that among the current hospitals of Shahid-Ali-Nasab had the best position in terms of passive defense to hazard management, and the hospitals of Imam Reza, Madani and Taleghani had a more unfavorable situation than others, as well as the northwest of Tabriz city. The best conditions regarding the passive defense and hazard management features are northwest parts of city for building new hospitals.
Methodology
To work with Artificial Neural Network, firstly, effective parameters to locate the hospital should be provided to the network as input layers. Then, a number of training points should be given to the network so that the network uses the training points to determine the impact of each of the input layers; in fact, the network has received the training needed to cope with new areas. Finally, the entire city of Tabriz has been provided to the trained network, and in the end, the network, using what has been learned, identifies the optimal locations for the hospital.
The neural network has several types. In this study, Multilayer Perceptron method was used with back-propagation algorithm to determine the optimal location of the hospital.
Result and discussion
After providing the necessary trainings to the network and run it, the result of the map of the optimal locations for the construction of the hospital was presented. The output is a valuable layer between zero and one.
Conclusion
The city of Tabriz is the provider of many health services and the city as one of the big cities of Iran has the potential to attack enemy targets during a possible attack. On the other hand, there are natural risk factors in the city. The need to examine the status of the current hospitals finding the right place to build a hospital. According to the mentioned cases, necessary studies were carried out and 13 criteria for the mentioned goals were determined. These criteria were determined using previous studies and natural conditions of the city.
The method used in this study was a neural network method, which was used with multi-layer perceptron method with error propagation algorithm. We have plotted results with a numerical value from zero to one. By examining the position of the current hospitals in Tabriz, it seems hospitals are located in the central regions of the city and are more likely to follow the population factor.
The results show that Ali Nasab Hospital has a better position in terms of passive defense to hazard management than other hospitals. The hospital also has an appropriate distance from the environmental threats, such as faults and streams, and in the distance from the critical centers at the time of target of a possible enemy attack, and it has access to the main routes and the first arteries, and open green spaces, which, in times of crisis, provide space for emergency relief and emergency hospital establishment. After that, Amir Al-Momenin and Artesh hospital have a more favorable situation than other hospitals. Shahid madani, Imam Reza, and Taleghani hospitals have the worst conditions than other hospitals. Considering that, most hospitals are in Tabriz 1 and 2 districts and those have no radial distances with other hospitals in the areas that two Shahid Madani and Imam Reza hospitals are these centers. Because the hospital should be have distance at least 1000 meters from the fuel supply centers, this is not adhered to the case in the Taleghani Hospital. There are two fuel centers in the 1000-meter hospital privacy. Accordingly, the southeast parts of Tabriz is the most unsuitable areas for construction of new hospitals, and the northwest were identified as the best areas for building new hospitals.