## 4 Discussion and Future Works  
This study presents valuable insights into employing TCP/IP socket programming-based mimic broadcasting with the Chrony NTP synchronization in a local WSN utilizing low-cost ADXL345 sensors. By utilizing two series of Raspberry Pi devices--specifically, the Raspberry Pi Zero 2W as sensor nodes and the Raspberry Pi 4 as the gateway--we demonstrate the feasibility of leveraging readily available hardware for data collection and synchronization tasks. The choice of TCP/IP socket programming as the data transmission backbone stems from its reliability. The implementation of the mimic broadcasting mechanism ensures efficient initiation of the start schedule for all RPi0-2W sensor nodes. Here, the RPi0-2W sensor nodes operate as clients, while the RPi4 serves as the server in socket programming. Additionally, the RPi4 plays the roles of receiving data as the gateway and providing NTP server functionality for RPi0-2W synchronization using Chrony in the background. Successful synchronization via Chrony NTP ensures precise time alignment among the sensor nodes. The integration of the DS3231 RTC module further enhances the functionality of the RPi0-2W sensor nodes, enabling them to maintain accurate time even during internet loss or power outages. The consistent amplitude of the collected data from ADXL345 sensors within RPi0-2W end nodes indicates the stability and reliability of the sensor nodes in capturing acceleration information. The absence of peak loss in the collected impulse response from the 3 DOF structure vibration under various impulse forces confirms the effectiveness of the sensor nodes in capturing the full range of vibrations. The synchronization using Chrony proves to be robust and efficient, as evidenced by the consistent dominant frequency observed in the magnitude spectrum of the preprocessed acceleration data. Spectrogram analysis provides additional insights into the frequency and time characteristics of the collected data, enhancing our understanding of the relationship between time and response to excitation in the structural system under study. Moreover, these findings pave the way for exploring new opportunities in the application of low-cost sensors within WSNs for SHM applications. In the context of FDD, where precise time alignment is crucial, further optimization in achieving precise time synchronization can be accomplished by leveraging the optimal wrapping path obtained from DTW. In this research, precise synchronization among the RPi0-2W sensor nodes was successfully achieved through the utilization of DTW synchronization. The DTW algorithm computed the optimal warping path, facilitating accurate alignment between the windowed acceleration data and their corresponding magnitude spectra. This study extends the application of DTW synchronization to WSNs using low-cost ADXL345 sensors, which are widely used due to their affordability and compact size. While DTW synchronization has been explored in various domains such as audio and speech recognition [47], domain adaptation [70], and time series analysis [71], this research demonstrates its effectiveness in WSNs. The implications of the findings are significant for the development and deployment of WSNs for OMA. The successful implementation of TCP/IP mimic broadcasting coupled with DTW precise synchronization addresses the challenges associated with achieving synchronization among sensor nodes in a cost-effective manner. This opens up possibilities for applications in structural health monitoring, environmental sensing, and industrial automation, where precise synchronization and reliable data transmission are crucial. From a broader perspective, the findings highlight the potential of synchronization techniques in enhancing the overall performance and reliability of WSNs. The utilization of low-cost sensors, such as the ADXL345, in combination with synchronization algorithms like DTW, offers a cost-effective solution for real-time data collection and analysis in diverse domains.