## 2 Emergency Representation Model
### Operation of a PSAP at ECU 911  
According to the management model developed for the ECU 911, each PSAP has a specific coverage area. During normal operation, all the alert calls are routed by the PSTN or cellular network to the nearest PSAP, at which evaluation groups receive and analyze the content of every alert; when it does not proceed, the call is saved for its posterior classification and processing. If the alert proceeds, it is automatically turned into an emergency and is transferred to the corresponding FRI. Then, the dispatching evaluator of the particular institution decides which resources will be moved to attend the emergency and whether it is necessary to coordinate with other FIRs, according to the emergency's relevance and affectation. This operation process is summarized in Figure 1a. The received alerts can originate from landline calls, cellphone calls, emergency buttons, reports from a member of a FRI, or detection by a surveillance camera evaluator. A relevant point in an emergency system description is the percentage of the participation of each FRI in the total number of emergencies attended in a PSAP. For the case of Quito, Ecuador, this information can be readily obtained from the statistics section of the ECU 911 Website [10]. As we can see in Table 1, from more than 1 million emergencies registered during 2014, the group including police, health, and transit services represented 92% of the emergencies. On the other hand, fire brigades, municipal services, risk management secretaries (RMSs), and military forces only represented the remaining 8%. The Integrated Security Service has created a dictionary that defines 121 variables used to characterize the attended emergencies. Filtering the information contained in these variables, it is possible to identify very specific events, details, and any other important information regarding with the emergency. Thus, the proposed event analysis system is illustrated in Figure 1b. The information of all the attended emergencies is saved in an SQL DB at each PSAP. For this work, a report of the emergencies attended by the PSAP in Quito was downloaded in a CSV file. Using Matlab(r) software (version 2017b, The Mathworks, Nattic, MA, USA, 2017), we organized the emergencies according to the parameters that we wanted to analyze in a _.mat_ file. Temporal, geographical, and statistical analyses were developed and combined in order to model the behavior of each FRI. The results of this analysis could  
Figure 1: Overview of a public safety answering point (PSAP): (**a**) basic operation; (**b**) proposed model. DB: database; FRIs: first response institutions. be subsequently used to send feedback to the PSAP managers, aiming to improve the response of the FRIs. The information regarding any emergency contains a register with times associated to all the instances produced in the PSAP (i.e., the time when the alert arrives, when it is transferred to the FRI, when the resource is dispatched, when the resource arrives at the event site, and when the emergency is closed with a report of results). With this information, it is possible to map the events within a given geographical region by chronological order and filter the emergencies by the year, month, day, or even hour. This analysis allows managers to understand the temporal behavior of the emergencies attended by each FRI. Examples of this kind of representation are illustrated in Figure 2, where it is possible to identify the emergencies that occurred during the third week of January, and they are represented by days and hours next to their map localizations. \begin{table}
\begin{tabular}{c c} \hline \hline
**Institution** & **Percentage** \\ \hline Police & 64.2 \\ Health services & 15.0 \\ Transit & 12.8 \\ Fire brigades & 3.0 \\ Municipal services & 2.8 \\ Military forces & 1.3 \\ Risk management secretaries & 0.9 \\ \hline \hline \end{tabular}
\end{table}