## 5 Results and Discussion
### Discussion of Results
#### 5.3.1 Measurement Accuracy  
The data measured during the test with the proposed sensor nodes were subsequently analyzed in detail. Figure 11 shows some representative values obtained with the position sensor. In this measurement case, the official test sensor only recorded the end positions of the loading conditions to limit the number of records and facilitate subsequent analysis. These positions are marked with a horizontal line at the y-coordinate of the corresponding measured value. In turn, it can be observed that the wireless position sensor takes several measurements until the final position of each loading condition is reached, providing the evolution of the position over the whole transition process between consecutive conditions. \begin{table}
\begin{tabular}{p{56.9 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Category\textbackslash{}Test** & **Low Frequency Fatigue Tests (Freq. \(\leq\) 1 Hz)** & **Acquisition Frequency Structural Tests (Freq. \(>\) 1 Hz)** & **High Acquisition Frequency Structural Tests (Freq. \(>\) 1 Hz)** & **Other Types of Tests** \\ \hline
**Operational features** & \(\bullet\) Wireless nature simplifies and accelerates the installation process and eliminates the need for connectors and routing cables, minimizing material consumption and removing the cable management complexity. Increased flexibility in sensor positioning facilitates the integration into a wide variety of specimen geometries. Absence of cables eliminates potential wiring errors, reduces preparation and installation time and enhances the scalability of the system. Easy deployment in hard-to-access areas without the constraints of cabling. The reduction in cable weight minimizes its impact on test specimens. & \(\bullet\) Direct connection to the computing center through mobile applications, for requesting information and sending alerts. Connecting new MQTT clients to the AIoT network is quick and easy to perform. Large amount of resources available to apply ML techniques to analyze and leverage the recorded data. Cloud services available to store large amounts of recorded data and apply deep analytics. Remote access to all the information from anywhere and on any device. & \(\bullet\) No interference from nearby radiofrequency sources, by selecting distant channels within the 2.4 GHz WiFi band. Security of the data transmissions guaranteed by means of SSL protocol. \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._  
Figure 11: Graphical representation of the data recorded with the position sensor and the official sensor of the test. The proposed AIoT architecture provides greater data logging capacity through the use of cloud services and data analysis by applying advanced AI techniques for anomaly and deviation detection. In structural testing and other types of short-duration tests, there are no significant limitations due to the number of data points recorded during the test. However, depending on the volume of data to be registered, the advantages of cloud support provided by AIoT networks can be leveraged, along with the advanced processing capabilities available in the cloud. Comparing the values measured by the wireless sensor with the official test value, the accuracy of the system can be appreciated, with an average error of 0.2% and low noise levels, except in the area of values less than 20 mm. In this specific zone, the sensor has technical limitations, which are already advanced in the manufacturer's technical specifications, so this sensor is not suitable for this range of values. It should be noted that this measurement area with a high noise level is outside the calibrated range, whose minimum position value was 50 mm. The accuracy of the measurements is ensured by the analysis of the test requirements conducted during the initial implementation phase of the architecture and through the calibration process. For other types of tests with different requirements, sensors with technical capabilities adapted to those requirements will be needed.