# Agreement Technologies for Coordination in Smart Cities
## 3 Applications
### Evacuation Coordination in Smart Building  
The objective of an evacuation is to relocate evacuees from hazardous to safe areas while providing them with safe routes. Present building evacuation approaches are mostly static and preassigned (e.g., [30]). Frequently, no coordination is available except for predefined evacuation maps. Still, due to the lack of overall evacuation network information, there might be casualties caused by too slow an evacuation on hazardous routes. _Real-time_ route guidance systems, which dynamically determine evacuation routes in inner spaces based on the imminent or ongoing emergency, can help reduce those risks. [PERSON] and [PERSON] in [31] proposed two heuristic flow control algorithms for a real-time building evacuation with multiple narrow doors: with no limitation on the number of evacuation paths and k required evacuation paths, respectively. [PERSON] and [PERSON] in [32] proposed a distributed system for the computation of shortest evacuation routes in real time. The routes are computed by decision nodes and are communicated to the evacuees located in their vicinity. However, this approach considers only the physical distance and the hazard present in each link and does not take into consideration crowd congestion on the routes.  
A dynamic, _context-sensitive_ notion of route _safety_ is a key factor for such recommendations, particularly because herding and stampeding behaviours may occur at potential bottlenecks, depending on (among other factors) the amount of people who intend to pass through them. Furthermore, smart devices allow guidance to be _personalised_, taking into account, for instance, the specific circumstance of the elderly, disabled persons, or families. In such settings, an adequate notion of _fairness_ of evacuation route recommendations is of utmost importance to assure the trustworthiness of the system from the standpoint of its users [33]: the guidance should not only achieve good overall performance of the evacuation process but must also generate proposals for each of its users that each of them perceive as efficient. Finally, large groups of people may need to be evacuated, so _scalability_ plays a key role.  
Our proposal concentrates on real-time situation-aware evacuation guidance in smart buildings. The system aims at assigning efficient evacuation paths to individuals based on their mobility limitations, initial positions, respecting individual privacy, and other evacuation requirements. In our approach, a network of smart building agents calculates individual routes in a decentralised fashion. Complex event processing, semantic technologies, and distributed optimisation techniques are used to address this problem. In addition, we use the notion of agility to determine _robust_ routes, in the sense that they are not only fast but also allow finding acceptable alternatives in case of upcoming contingencies.  
We rely on the existence of a rather extensive set of possible evacuation routes, which may be determined by evacuation experts or through some automated online or offline process. The different  
Figure 7: Moving average of travel times.  
evacuation routes are stored in an emergency ontology that, together with an ontology describing the topological structure of the building, specifies the a priori knowledge of our system. In addition, situational knowledge about the current situation in each moment of the building and of the evacuees is generated in real time through a network of sensors. This dynamic knowledge is merged with the static knowledge about the infrastructure. In an emergency situation, semantic inference is used to select the most appropriate agile evacuation route for each individual in the building. Furthermore, real-time monitoring allows the system to reroute evacuees in case of contingencies and, thus, to propose evacuation routes that are adaptive to unpredictable safety drops in the evacuation network.