# Agreement Technologies for Coordination in Smart Cities
## 3 Applications
### Emergency Medical Service Coordination  
The domain of medical assistance includes many tasks that require flexible on-demand negotiation, initiation, coordination, information exchange, and supervision among different involved entities (e.g., ambulances, emergency centres, hospitals, patients, physicians, etc.). In addition, in the case of medical urgencies, the need for fast assistance is evident. It is of crucial importance for obtaining efficient results, improving care, and reducing mortality, especially in the case of severe injuries. Out-of-hospital assistance in medical urgencies is usually provided by emergency medical assistance (EMA) services, using vehicles (typically ambulances) of different types to assist patients appearing at any location in a given area. In such services, the coordination of the available resources is a key factor in order to assist patients as fast as possible. The main goal here is to improve one of the key performance indicators: the response time (the time between a patient starting to call an EMA service centre and the moment medical staff, e.g., an ambulance, arrives at his location and the patient can receive medical assistance). One way to reduce response times consists of reducing the part that depends on the logistic aspects of an EMA service through an effective coordination of the assistance vehicle fleet (for simplicity, here we assume a fleet of ambulances). In this regard, there are two principal problems EMA managers are faced with: the assignment or allocation of ambulances to patients and the location and redeployment of the ambulance fleet. The assignment or allocation problem consists of determining, at each moment, which ambulance should be sent to assist a given patient. Moreover, the location and redeployment consist of locating and possibly relocating available ambulances in the region of influence in a way that new patients can be assisted in the shortest time possible. Most of recent works for coordinating ambulance fleets for EMA have been dedicated to the redeployment problem. A lot of work has concentrated on the dynamic location of ambulances,where methods are proposed to redeploy ambulances during the operation of a service in order to take into account the intrinsic dynamism of EMA services (e.g., [39; 40; 41]). Most proposals on dynamic redeployment of ambulances only consider the possibility to relocate ambulances among different, predefined sites (stations). This requirement is relaxed in the work proposed in [42], where a number of ambulances can be relocated to any place in the region. Regarding dispatching strategies (the patient allocation problem), most works use the \"nearest available ambulance\" rule for assigning ambulances to patients in a first-came first-served manner. Some works analyse priority dispatching strategies to account for severity level of patients [42; 43]. In our previous work [44], we proposed a system that re-allocates ambulances to patients and redeploys available ambulances in a dynamic manner in order to reduce the average response times. Our redeployment approach differs from others in the sense that it does not try to maximise the zones that are covered in a region, with respect to some time limits. Instead, the approach is based on geometric optimisation that tends to optimise, in each moment, the positions of all ambulances that are still available such that the expected arrival time to potential new emergency patients is minimised. Here, with regard to the allocation of patients to ambulances, we propose a dynamic approach similar to [45] but, instead of optimising the global travel times of all ambulances, we concentrate only on the sum of the arrival times of ambulances to the pending emergency patients. This system is summarised in this section. We use the following notation to describe the problem and to present our solution. The set of ambulances of an EMA service is denoted by \(A=\{a_{1},\,\ldots,\,a_{n}\}\), where \(n\) is the cardinality of \(A\).