# A Novel Intelligent IoT System for Improving the Safety and Planning of Air Cargo Operations
## 3 System Integration and Testing
### System's Limits Testing  
A separate set of field tests regarding the identification of the system's limitations and its response to unforeseen events was also performed. These tests revolved around two main axes that affect its functionality, namely power, and communication loss. The entirety of the tests performed, including the testing method, the response of the subsystem involved in the testing scenario, and the messages that the end-user receives via the HMI is presented in Table 3. \begin{table}
\begin{tabular}{c c c c} \hline
**Unforeseen Situation** & **Test Method** & **System Response** & **End-User Perception** \\ \hline \multirow{6}{*}{Abrupt power source loss} & Disconnect one or more cells of the battery providing power to the RMC unit & The system instantaneously switches to the other battery, without any loss of data or interruption of the system’s normal operation & A very low percentage is reported in the corresponding battery report on the HMI \\ \cline{2-4}  & Disconnect the battery providing power to the RMC unit & The system instantaneously switches to the other battery, without any loss of data or interruption of the system’s normal operation & The corresponding battery percentage in the battery report on the HMI switches to \% \\ \cline{2-4}  & Disconnect both batteries providing power to the RMC unit & The RMC unit stops functioning & The user receives no new ULD status reports in the HMI. The latest report’s cardinal number and retrieval time do not update \\ \hline \multirow{2}{*}{New power source connection} & Connect a new battery pack while the system is already operating on another battery pack & The system resumes its operation powered by the battery it currently operates on & The battery percentage corresponding to the newly connected battery in the battery report on the HMI switches to the actual battery percentage \\ \hline \multirow{6}{*}{Connection loss between ULD and HMI in normal operation} & Having the HMI in hand, move away from the test area or into a spot with multiple walls and beams between the HMI and the ULD & The RMC unit tries to reconnect to the HMI and restarts its operation after 5 tries & The user receives no new ULD status reports in the HMI. The latest report’s cardinal number and retrieval time do not update \\ \cline{2-4}  & & The HMI stops receiving status reports from the ULD & The user receives new ULD status reports in the HMI. The latest report’s cardinal number and retrieval time do not update \\ \hline \multirow{2}{*}{Connection re-establishment between ULD and HMI in normal operation} & Having the HMI in hand, move into the test area or into a spot with few obstacles between the HMI and the ULD or the RMC unit’s antenna & The RMC unit reconnects to the HMI and restarts its operation in the last state set in the HMI & The user receives new ULD status reports in the HMI. The latest report’s cardinal number and retrieval time update \\ \hline \multirow{2}{*}{Connection loss between ULD and/or the robotic platform and/or the HMI in loading/unloading operation} & Having the HMI in hand, move away from the test area or into a spot with multiple walls and beams between the HMI and the robotic platform & The RMC unit tries to reconnect to the HMI and restarts its operation after 5 tries & The user sees an indication status in the HMI and restarts its operation after 5 tries & The user sees an indication status in the HMI signifying the communication interruption with the robotic platform \\ \cline{2-4}  & & The HMI stops receiving status reports from the robotic platform & The robotic platform \\ \hline \end{tabular}
\end{table} 
Table 3: Test cases for the system’s response to unforeseen events. The tests presented in Table 3 were executed multiple times, according to standard testing practice. Three typical test cases are presented to demonstrate the system's response to several unpredictable events.