## 6 Experiments
### Validation Experiments  
The proposed system has been validated in experiments in close-to-operational conditions carried out at two floors of the L1 Laboratories building of the School of Engineering of Seville. There are two stairs between both floors, each of them is modeled with a vertex in the building graph. The building has two exits at the first floor. The building has no previous WSN infrastructure. The proposed system was set with the values used in Section 6.1.1. For safety reasons, the experiments were carried out with no real fire. Below the story of the experiment and some results are summarized. A fire was declared in the building. Soon, the fire brigade arrived. After a quick analysis, they decided the WSN deployment. Two firefighters equipped with mobile nodes entered the building and started deploying the nodes--beginning with the first floor--at assigned locations. Once deployed, each static node started dynamically creating the CTP routing channels. They also interchanged _RegrRequest_ and _RegrResp_ packets and obtain their RSSI-range models. After a short delay, fire/smoke measurements were received at the Base Station. FIREMAN2 detected a fire at the second floor. He stopped deployments. His finding was confirmed by nodes ID = 47, ID = 41 and ID = 35, which sensed abnormal \(CO_{2}\) measurements. The rest of the nodes measured normal readings. Meanwhile the Base Station computed escape paths using fire measurements and flooded the local guiding information for each WSN node. Figure 13 shows with arrows the local guiding information stored in the nodes in each room. When the firefighter activated their mobile nodes, they started broadcasting _LocRequest_ packets and receiving _LocResp_ packets from nearby static nodes. Each mobile node computed its own location and created _FiremanSense_ packets that were sent to the Base Station. The firefighter location and measurements were visualized and registered by the Base Station. At time \(t_{1}\) [PERSON] found a group of students in a room on the second floor. He stopped deploying nodes and activated the Escape Guiding Functionality in his mobile node. The mobile node started broadcasting _EscapeRequest_ packets and receiving _EscapeResp_ packets from nearby nodes. The escape path passed from the second to the first floor using STAIRS1. [PERSON] followed the escape path and guided the students out of the building at EXIT1. Figure 13 also shows the trajectory of [PERSON] estimated by the proposed localization method while the Escape Guiding Functionality is active. After a while, node ID = 3 detected a low concentration of hydrocarbon gases, see Figure 14. The head of the fire brigade was informed that there was a Fuel Cell Unit in a room on the first floor. Then, the Base Station operator manually assigned that and the surrounding rooms with high costs in the escape path computation module. As a result, the optimal escape paths were updated and _GuidingInfo_ packets with the new guiding information were flooded in the WSN. Static nodes updated their local guiding information, represented with arrows in Figure 14. At time _t2_ [PERSON] got to extinguish the fire. To get out of the building he activated the Escape Guiding Functionality in his mobile node. In this case, the escape path used STAIRS2 and EXIT2. Figure 14 shows in dashed line the actual trajectory estimated by the proposed system while the Escape Guiding Functionality of FIREMAN2 was active. A straight-line representation of the escape path is also depicted in solid line. Figure 15 compares both (straight-line representation and actual locations) in \(X\) and \(Y\) axes. Figure 14: Maps of the second (**a**) and first (**b**) floors of the building with fire conditions and guiding information at time \(t_{2}\). The straight-line representation of the escape path (dashed line) and the actual trajectory followed by [PERSON] (solid line) are also shown.