esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 O-RAN with 200 m FSO Link
### Preoperation and Measurement of 200 m FSO Link Election
Figure 8 illustrates the outcomes of the physical network connection. The physical network can provide actual connections for subsequent O-RAN users, and it should be clarified that the campus network traffic limit is 100 Mbps. The ITB is the network source routed through the switch to enable the PC to conduct network performance measurements and is transmitted to the FSO device for subsequent transmission. The transmission then proceeds to the EB and is routed through the switch for the PC to perform network performance measurements. Evidently, the average values of uplink (UL) throughput, downlink (DL) throughput, and ping measured at the ITB before the 200 m FSO transmission at 2-min intervals were 92.051 Mbps, 89.527 Mbps,  
Figure 7: **(a)** Information on the performance operation constraints of receiving power and masking time of the FSO device. **(b)** Measurement of FSO device transmit/receive power and throughput under different weather conditions (three different weather symbols correspond to the corresponding weather conditions, such as sun, cloudy, and rain). and 4.63 ms, respectively. The average values at the EB post-FSO transmission, on the other hand, were 92.165 Mbps, 88.785 Mbps, and 5.367 ms for uplink throughput, downlink throughput, and ping per 2-min sampling. This approximate measurement result indicates that the 200 m FSO link had a minimal impact on network performance.
# Reliability and Validity of the Portable KForce Plates for Measuring Countermovement Jump (CMJ)
## 5 Conclusions  
The aim of our study was to test the reliability and validity of the portable KForce plates for measuring CMJ in collegiate athletes deriving from various sports backgrounds.  
Our findings suggest that the KForce Plates system is a reliable and valid tool that can be used by experts in the sports field. Although the portable KForce Plates system and the My Jump 2 application were found to be comparable tools for assessing CMJ, the portability, ease of use, and assessing parameters make the KForce Plates system the best option for clinical practitioners when evaluating either professional or amateur athletes.  
In conclusion, technological advancement has facilitated the automatic calculation of the data, the portability of the platforms, and the affordability of the accompanying equipment. Future studies could explore the reliability and validity of the portable KForce plates on other jump tests with the concurrent use of the gold standard in-ground force platforms. They could also test the reliability and validity of athletes deriving from different sports backgrounds (e.g., elite or amateur athletes) or specific sports (e.g., football) in order to reduce the risk of injuries and improve sports performance.  
Conceptualization, G.P. and M.P.; methodology, G.P., M.P., M.M. and G.A.K.; software, G.P., D.Z., E.-M.P. and E.P.; validation, G.P., E.P., M.M., G.A.K. and M.P.; formal analysis, G.P. and M.P.; investigation, G.P., D.Z. and E.-M.P.; resources, G.P.; data curation, G.P. and M.P.; writing--original draft preparation, G.P.; writing--review and editing, G.P., D.Z., E.-M.P., E.P., M.M., G.A.K. and M.P.; visualization, G.P., D.Z., E.-M.P., E.P., M.M., G.A.K. and M.P.; supervision, M.P.; project administration, G.P. and M.P. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
This study was accepted by the Ethics Committee of the University of West Attica (No. 18030).  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to ethical restrictions.  
The authors thank the Department of Physiotherapy of the University of West Attica for its services.  
The authors declare no conflict of interest.
## 4 Conclusions  
The tensile response of the RSCPB was analyzed, and the tensile strength and strain of RSCPB were studied and discussed based on the Brazilian split tensile test. The main conclusions that were obtained are as follows:  
1. Tensile stress-strain curves indicate that RSCPB has a larger elastic modulus. ITS of RSCPB is greater than CCPB. Most of the RSCPB and CCPB specimens are characterized by brittle fracture, of which only a small proportion of the RSCPB specimens exhibit residual strength characteristics. High sulfur (S\({}^{2-}\)) content in the tailings has a negative impact on the long-term strength of RSCPB.
2. The ITS of the RSCPB increased by \(-38.10\%\) to \(346.15\%\) compared to CCPB; ITS was generally improved in the initial 7 days and generally lowered at 28 days of curing. Meanwhile, the tensile strain increased by \(-33.54\%\) to \(277.97\%\), which was generally lower compared to CCPB, indicating that RSCPB is still a brittle material. The analysis results showed that CPB specimens' brittleness was enhanced with the addition of fibers.
3. The effects of RS fiber content and length on RSCPB tensile strength and strain are not linear, and different curing ages lead to different effects. In engineering applications, the appropriate formulation should be selected based on the requirements.
4. The rough surface of RS fibers can adsorb the hydration products to form large aggregates; moreover, increasing the cement content helps to enhance the CPB denseness. Furthermore, the calcium alumina in the hydration products has a negative effect on the mechanical properties of RSCPB.  
Conceptualization, X.C. and Z.L.; methodology, X.C.; software, Z.L.; validation, X.S. and X.C.; formal analysis, X.C. and Z.L.; investigation, X.C.; resources, X.S.; data curation, X.C.; writing--original draft preparation, Z.L.; writing--review and editing, X.C.; visualization, Z.L.; supervision, X.S.; project administration, X.S. and X.C.; funding acquisition, X.C. and X.S. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation Project of China, grant number 51874350 and Hunan Provincial Natural Science Foundation Project, grant number 2021 JJ40733.  
Not applicable.  
The data are contained within the article.  
We are grateful to Shenzhen Zhongjin Lingnan Non-ferrous Metal Company Limited for providing us with the tailings and Central South University for providing us with the experimental platform.  
The authors declare no conflict of interest.
# Artificial Intelligence of Things as New Paradigm in Aviation Health Monitoring Systems
## 4 Discussion
### Enhancements Achieved through the AloT Framework  
The proposed AloT framework for aviation health monitoring systems demonstrates significant improvements across multiple areas of aircraft operations and maintenance. This integrated approach enhances predictive accuracy, operational efficiency, safety, maintenance optimization, and cost reduction.  
The framework's ability to monitor up to 20,000 parameters via the FMDE provides a comprehensive view of aircraft health. This vast dataset, coupled with advanced AI algorithms, enables the identification of subtle correlations and patterns that would be impossible for human analysts to detect. The system's continuous learning capability allows for ever-improving prediction accuracy over time.  
Operational efficiency is significantly enhanced through real-time data processing and analyses, allowing for rapid decision-making. The system optimizes maintenance scheduling by accurately predicting needs, reducing unnecessary checks, and scheduling required maintenance at the most opportune times. This approach has the potential to decrease unscheduled maintenance events, thereby reducing aircraft downtime.  
The framework also contributes substantially to aviation safety. By enabling early detection of subtle anomalies that might escalate into serious problems, the system allows for proactive addressing of issues. Real-time health status monitoring of all critical systems provides pilots and ground crews with more accurate situational awareness. Moreover, by analyzing data across entire fleets, systemic issues can be identified and addressed before they lead to incidents. Analyses of historical data suggest that such proactive monitoring could potentially prevent many maintenance-related incidents.  
The AloT framework facilitates a shift from time-based to condition-based maintenance strategies. Each aircraft's maintenance can be tailored based on its specific usage patterns and operating conditions. Components can be replaced based on their actual condition rather than at fixed intervals, optimizing their lifecycle. AI-driven analyses allow for dynamic adjustment of maintenance plans in real-time based on operational needs and component health.  
From a financial perspective, the AloT framework contributes to significant cost reductions. By accurately predicting maintenance needs, costly unscheduled repairs and associated disruptions are minimized. The system enables more accurate part inventory management, reducing overstock and storage costs. Maintaining components based on their actual condition extends their useful life, reducing replacement frequency. Additionally, continuous monitoring and adjustment of aircraft systems can lead to optimized performance and fuel consumption.  
The AloT framework represents a significant advancement in aviation health monitoring, with the potential to transform the industry. As these technologies continue to evolve and mature, we can anticipate even greater benefits and innovations in aircraft operations, maintenance, and safety.
## 3 Results and Discussion
### Validation of the Low-Cost Acquisition System in a Thermoacoustic Engine  
This section details the quality criterion established for validating the performance of the Arduino low-cost system against the B&K system. Both the Arduino and B&K systems have high input impedance (Arduino: \(10^{7}\)\(\Omega\), B&K: \(10^{6}\)\(\Omega\)), ensuring accurate measurements despite parallel connection. Notably, while the B&K system is significantly more expensive, the Arduino provides a cost-effective alternative without compromising accuracy.  
The validation process involves analyzing the resultant parameters from each P1.1 and P1.2 sensor pressure signal independently and calculating the percentage of absolute error:  
\[Error=\left[\frac{M_{Brel}-M_{Arduino}}{M_{Brel}}\right]\times 100, \tag{7}\]  
considering \(M_{Brel}\) as the measurements from the high-cost system (the real and hence more accurate values) and \(M_{Arduino}\) as the measurements from the low-cost acquisition system presented in this paper. Figure 13 presents four measurements corresponding with four different pressure and frequency values. This was achieved by modifying the position of the valve.  
The comparison between the Arduino and B&K systems revealed discrepancies in pressure amplitude and frequency measurements that were typically less than 1.6% and 0.3% of reading, respectively. These results clearly demonstrate and confirm the good performance of the low-cost system.  
Figure 12: Sinusoidal fitting from original P1.2 and P2 sensor readings, and wave parameter results obtained from the data post-processing.
###### Abstract  
Rice growing under anaerobic conditions followed by spring wheat under an aerobic environment differentially impact the net ecosystem exchange (NEE) of carbon dioxide (CO2) in rice-wheat systems of the north-western Indo-Gangetic Plains (IGP). This is the first estimation of the NEE in a rice-spring wheat sequence via the eddy covariance technique in the north-western Indo-Gangetic Plains, which was partitioned into gross primary productivity (GPP) and ecosystem respiration (RE) and correlated with the environmental variables. Higher CO2 uptake of \(-\)10.43 g C m\({}^{-2}\) d\({}^{-1}\) was observed in wheat during heading as compared to \(-\)7.12 g C m\({}^{-2}\) d\({}^{-1}\) in rice. The net uptake of CO2 was 25% lower in rice. The average daily NEE over the crop season was \(-\)3.74 and \(-\)5.01 g C m\({}^{-2}\) d\({}^{-1}\) in rice and wheat, respectively. The RE varied from 0.07-9.00 g C m\({}^{-2}\) d\({}^{-1}\) in rice and from 0.05-7.09 g C m\({}^{-2}\) d\({}^{-1}\) in wheat. The RE was positively correlated with soil temperature at 5 cm depth (0.543, \(p<0.01\)) in rice and with air temperature (0.294, \(p<0.01\)) in wheat. The GPP was positively correlated with air temperature (0.129, \(p<0.05\)) and negatively correlated with vapor pressure deficit (VPD) (\(-\)0.315, \(p<0.01\)) in rice. In wheat, GPP was positively correlated with air temperature (0.444, \(p<0.01\)) and soil moisture (0.471, \(p<0.01\)). The rate of GPP over the crop duration was nearly the same in both rice and wheat, however, the RE was higher in rice as compared to wheat, thus, the ratio of cumulative RE/GPP was 0.51 in rice and much lower at 0.34 in spring wheat. Rice contributed 46% and 43% to the annual totals of RE and GPP, respectively, while spring wheat contributed 36% and 51%. The NEE of CO2 was higher in spring wheat at \(-\)576 g C m\({}^{-2}\) d\({}^{-1}\) as compared to \(-\)368 g C m\({}^{-2}\) in rice. Thus, while estimating the carbon sink potential in the intensively cultivated northern IGP, we need to consider that spring wheat may be a moderately stronger sink of CO2 as compared to rice in the rice-wheat system.  
net ecosystem exchange; ecosystem respiration; gross primary productivity; eddy covariance micrometeorological technique +
Footnote †: journal: Journal of Laal 2021, 10, 701. [[https://doi.org/10.3390/land10070701](https://doi.org/10.3390/land10070701)]([https://doi.org/10.3390/land10070701](https://doi.org/10.3390/land10070701))
# Research on the Jiamusi Area's Shallow Groundwater Recharge Using Remote Sensing and the SWAT Model
Compared with traditional methods, the remote sensing water balance method has the advantage of integrating a global road surface data assimilation system and RSGIS and provides faster and more convenient data retrieval. These technologies are also the focus areas of current research and the future development direction [12]. In addition, the large coverage area and small temporal resolution of remote sensing significantly reduce the influence of the rainfall infiltration coefficient method on geological water storage and runoff, which are often neglected factors [13], and improve the accuracy of groundwater resource calculation. In addition, in order to improve the accuracy of the research results, the SWAT model was also adopted in this study. On the basis of identifying the sensitive factors, the model uses the hydrological response units divided by the model to maintain the regional consistency of climate, soil, and land use and verify the applicability of the model. Subsequently, the shallow groundwater resources in the whole study area were evaluated. This study has important reference values for the restoration of groundwater levels and agricultural and grain production in the Sanjiang Plain.
###### Abstract  
The beat signal obtained from frequency-modulated continuous-wave (FMCW) radar is a waveform that is corrupted by noise and requires filtering out interference components for frequency calibration. Traditional FFT methods are affected by the fence effect and spectral leakage, leading to a reduction in frequency estimation accuracy. Therefore, an improved double-spectrum-line interpolation frequency estimation algorithm is proposed in this paper, utilizing spectral refinement and phase interpolation. Firstly, the post-FFT spectral signal is refined to narrow the frequency search range and enhance frequency resolution, thereby separating the noise signal. Then, a frequency deviation factor is defined based on the relationship between adjacent phase angles. Finally, the signal's phase angles are interpolated using the frequency deviation factor to estimate the frequency of the beat signal. Experimental results demonstrate that the proposed algorithm reduces the impact of quantization on the frequency distribution and increases the signal's noise resistance. The proposed algorithm has a higher accuracy and lower standard deviation compared to the recently proposed algorithm.  
beat signal; frequency estimation; spectral refinement; phase angle interpolation 2024 14 7067. [[https://doi.org/10.3390/app14167067](https://doi.org/10.3390/app14167067)]([https://doi.org/10.3390/app14167067](https://doi.org/10.3390/app14167067))  
1
## 4 Calibration and Analysis of Rotation Axis Position Error
### In-Machine Measurement of the Center Point of Precision Ball Column
#### 4.1.2 On-Line Measurement of Spherical Detection Points  
The diameter of the contact trigger probe used in the experiments was 6 mm. The experimental set up and the relevant parameters of infrared probe are summarized in Table 2.  
Ceramic material Al\({}_{2}\)O\({}_{3}\) was used as the material of precision balls with diameter 34.925 mm. The diameter tolerance of the sphere was 0.5 microns and the surface roughness was 0.04, which met the requirements of measurement accuracy. The experiments were carried out on TOPNC VMC-C50 five-axis machine tool, as shown in Figure 5. Some of the measured data are summarized in Table 3.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**The Technical Requirements** & **Parameters** \\ \hline External dimension of the Probe & Diameter: \(\Phi\)55 mm, length:95 mm \\ Standard probe length & 60 mm \\ Direction of measurement & \(\pm\)X, \(\pm\)Y, \(-\)Z \\ Unidirectional repeat accuracy of the Probe & 0.001 mm (2\(\sigma\)) \\ The maximum Angle of swing of the probe in the XY plane & 15\({}^{\circ}\) \\ \hline \hline \end{tabular}
\end{table}
Table 2: The parameters of the Pioneer OP550 Probe.  
Figure 5: On-machine detection of precision balls.
## 2 Materials and Methods
### Oxide Surface Characterization  
Glancing angle X-ray diffraction (XRD, XDS 2000, Scintag, Franklin, MA, USA) with a 1\({}^{\circ}\) rotation angle from the Cu-K\({}_{\alpha}\) source was used to determine the crystalline phases in each oxide. Multiple specimens (n = 4) were scanned over a 20 angle range of 20\({}^{\circ}\) to 60\({}^{\circ}\) at a speed of 2\({}^{\circ}\) per minute. Optical microscopy (Keyence, Osaka, Japan, VHX-1000) was used to examine the macroscopic surface topography of each oxide. Scanning electron microscopy (SEM, Zeiss, Jena, Germany, Supra 40) was used to examine each oxide's microscopic and nanoscopic surface topography. A 12 kV SEM accelerating voltage was used for microscopic images, while a lower 9 kV SEM accelerating voltage was used for nanoscopic images. Energy-dispersive X-ray spectroscopy (EDS, EDAX, Mahwah, NJ, USA, APEX EDS Software Suite, Advanced Version 2.5.1001.0001) was used with a 12 kV SEM accelerating voltage to determine the dopant elements incorporated into each oxide. Additionally, attenuated total reflectance fourier transform infrared spectroscopy (ATR FTIR) analysis was used over a scan range of 650-4000 cm\({}^{-1}\) to capture the molecular compounds present in the oxides.
# Interplanetary Student Nanospacecraft: Development of the LEO Demonstrator ESTCube-2
## 1 Introduction
### ESTCube-2 Project's Development Timeline  
While in 2014, most seasoned members were spending their days and nights operating and troubleshooting the ESTCube-1, a new student team developed the initial ESTCube-2 design, which was improved as new ESTCube-1 results were analyzed. By the middle of 2015, the student team of ESTCube-2 was established, supervised by a few remaining ESTCube-1 members. The Estonian Student Satellite Program was entirely led and managed by MSc and Ph.D. students. In the autumn of 2015, the ESTCube-2 team recruited new members for fundraising, marketing, communications, and human resources, who were highly motivated but often inexperienced. The ESTCube-2 design was revised in the winter of 2015-2016 when two new payloads were added. Since 2015, ESTCube-2 mechanical and electronic hardware has been iterated multiple times, although most of it happened in the latter stages of the project, as discussed in Section 3.1. Software development has been a continuous process since 2015 and is still ongoing, as addressed in Section 3.2.  
[PERSON] joined the first recruitment campaign and offered fundraising help. As a well-connected Estonian startup pioneer, [PERSON] connected the ESTCube-2 team with [PERSON], the Skype and Starship Technologies co-founder. These contributions helped to start the development process, and the project gained popularity nationally and internationally.  
Furthermore, in the spring of 2017, the ESTCube-2 marketing and fundraising teams led a Hooandja crowdfunding campaign which raised more than 38,000 EUR from more than 500 backers [30].  
In the summers of 2017-2019, the ESTCube-2 team welcomed the first generation of SpaceTEM students: an Estonia-Latvia Program to train the next generation of entrepreneurs. In 2018, the European Union, in cooperation with the European Space Agency via the In-Orbit Demonstration and Validation (IOD/IOV) initiative, granted UT Tartu Observatory an ESTCube-2 launch opportunity with VEGA-C launcher.  
During 2022, the team performed minor electronics and mechanics changes as payloads were delivered and integrated into the satellite. Section 3.3 addresses the payload integration process. At the end of 2022, the satellite was tested for electromagnetic compatibility (EMC), shock, and vibration launcher requirements, where the last two showed some minor problems that the team was able to solve.  
In March 2023, the ESTCube-2 completed its radio frequency coordination process after five years due to various delays and changes in the development. At the time of writing (May 2023), the ESTCube-2 software tests are being performed to ensure reliable in-orbit software updates, software error handling, and payload functionality before the autumn 2023 launch onboard the VEGA-C VV23 rocket.
## 2 Numerical Simulation Calculation Methods and Model Validation
### Numerical Simulation Calculation Methods
#### 2.1.2 Aerodynamic Performance Calculation Method  
For this study, the maximum blade tip speed u of the axial flow fan is less than 0.3 Mach; the simulation can therefore be carried out using a mathematical model of the three-dimensional incompressible flow field. The main boundary conditions for axial fans are set as pressure inlet and pressure outlet. The steady calculation adopted a multiple reference system model (MRF), the working fluid is air, and the impeller duct setting is to rotation duct. The solution adopted the pressure-based implicit solver. And the k-\(\omega\) turbulence model was used to solve the three-dimensional Reynolds-averaged Navier-Stokes (N-S) equation. The SST k-\(\omega\) turbulence model [25,26] is a two-equation model derived from a combination of k-\(\varepsilon\) and k-\(\omega\). The combined model uses the k-\(\omega\) model in the wall region where the viscous influence is more pronounced. In contrast, the k-\(\varepsilon\) model is used in the region where the turbulent flow is fully developed, thus avoiding the impact of minor disturbances in the incoming flow on the simulation calculations. The SST k-\(\omega\) turbulence model gradually changes from the standard k-\(\omega\) model inside the boundary layer to the high Reynolds number k-\(\varepsilon\) model outside. The SST k-\(\omega\) turbulence model achieves a gradual change from the standard k-\(\omega\) model inside the boundary layer to a high Reynolds number k-\(\varepsilon\) model outside the boundary layer. The SIMPLE (Semi-Implicit Method for Pressure-Linked Equations) algorithm was applied to couple the pressure and velocity. The index parameters of each aerodynamic performance were set to the second-order upwind. When the value of each calculation residual is less than the convergence residual of \(1\times 10^{-5}\), the convergence is considered.  
The equation of the SST k-\(\omega\) turbulence model is as follows:  
\[\frac{\partial k}{\partial t}+\
abla\cdot(\mathbf{u}k)=P_{k}-\beta^{*}k\omega +\
abla\cdot\left[