## 4 Experimental Results and Clinical Feedback  
The electronic ambulance concept was tested for 60 days in cooperation with employees and patients at the clinical and radiation oncology clinic of the Zilina Hospital. For the testing, a group of medical professionals and patients was used. Group members were provided with professional consultations in case of problems. In total, two oncology clinics and one hundred patients were included in the testing process. The number of patients was selected based on the average number of patients in outpatient clinics during normal operation. Patients were selected based on their age and willingness to cooperate. Eighty-five patients had a mobile device with Android operating system and NFC-HCE functionality. The remaining 15 patients received an NFC tag. Selected outpatients were given a loaned tablet on which they had access to the Firebase database and an NFC module. Prior to testing, patients and staff received the necessary instructions for using the proposed application. First, the emphasis was placed on the objectivity of testing. Upon arrival, the patient connected his mobile device to the NFC module with his request. Within tens of seconds, patients came one after the other and the database was filled. At the same time, the nurse in the clinic was preparing the medical documentation. When the nurse saw in the database that there was a patient who needed to go to the ambulance, she was able to react quickly and change the order of patients as needed. To demonstrate the improvement in efficiency, we measured the waiting time of patients in an ambulance waiting room for each procedure with and without the application and the NFC module, Figure 8.  
Measurements without the app were taken during a normal working day. For each patient who arrived, we tracked the time from the moment they knocked on the clinic door to the time their request was processed. Measurements with the mobile app were the same. The time from the addition of the patient to the database to the resolution of his request was measured. Furthermore, Figure 8 shows that the biggest time-saving is when requesting an examination. The nurses explained to us that patients make their requests by phone. Figure 8: Experimental results: improvement in efficiency due to the NFC electronic ambulance application: patient waiting time progress. The doctor then prepares for them, and after the patient arrives in the waiting room, the nurse just hands over the request form. Thanks to the application, the patient does not have to wait in the waiting room for 40 min, but only about 4 min. The second most effective step is an acute blood test. This is because patients for such an operation come for collection early in the morning, and after receiving the blood results, they continue for chemotherapy. The reason for reducing the waiting time for patients with an acute request for a blood test is the fact that when they see such a patient in the database, they prioritize him over others. The following improvements to waiting times are when patients come to \"Other\". These are mostly questions that the medical staff can respond to quickly. The control examination is the reason for the visit to the oncology clinic and the time for this is effectively shortened. This point is mainly influenced by the examination being carried out by a certified doctor. However, the average time spent in the waiting room that is saved by the mobile application is about 80 min. The positive feedback from the medical staff was mainly that thanks to the application and the organization of other work tasks, they could better redistribute time between their patients and thus significantly shorten the waiting time. Figure 9 shows the UML diagram depicting the practical value of the proposed solution: improvement in time-efficiency via red-line shortcuts. For the remaining points, we can also observe significant time-savings. This fact can be illustrated by the fact that there is also a great benefit in the database of waiting patients.