esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Measurement Improvement by Time Aggregation
### The Analysis of Time Aggregation to Mitigate the Effects on Amplitude
Table 1 also indicates the total common RMS value of 19.243 Vrms, obtained by adding all the spectral bars and aggregating their values along three windows (which coincides exactly with the theoretical value, \(\sqrt{13.2^{2}+9.8^{2}+10^{2}}\), if all the components of the studied example are considered). It can be observed that the repetition period to obtain the total common RMS value, containing all the spectral bars, is the same as for each group of frequencies, since only an interharmonic has been considered (that is the cause of the leakage that affects the whole spectrum, and therefore, rotates at the same speed in all the spectral bars). If there were multiple interharmonics, there would be areas of the spectrum with different ideal aggregation time related to other areas and the full spectrum, depending on the proximity and influence of the different interharmonics causing the spectral leakage producing this lack of synchronization.
## 3 Experiment Results and Analysis
### Stiffness Degradation  
Figure 16 uses the secant stiffness to reflect the accumulation of structural damage at the two groups of connectors under external loads expressed as follows.  
\[K=\frac{|+F_{i}|+|-F_{i}|}{|+X_{i}|+|-X_{i}|} \tag{1}\]  
where \(F_{i}\) and \(X_{i}\) are the peak load and peak displacement in the \(i\)-th loading regime, respectively. The initial stiffness of specimen FW-2 is smaller than that of specimen FW-1, and the stiffness degradation rate is slower in the middle and later stages of the test. It is due to the bolt sliding in the long circular hole of the ALC pendulums Z-panel connector, which creates a buffer zone between the frame and the ALC panel. At the beginning of the test, the provision of the long circular hole reduces the lateral stiffness of the overall structure and the effect of seismic loading on the ALC panel, while increasing the stability of the ALC panel. In the later part of the test, the bolt contacts the edge of the long circular hole of the connector and provides load-bearing capacity for the whole structure.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Specimen**} & \multicolumn{2}{c}{**Yielding Point**} & \multicolumn{2}{c}{**Ultimate Point**} \\ \cline{2-5}  & \(\mathbf{P_{y,t}}\) & \(\Delta_{y,t}\) & \(\mathbf{P_{m,t}}\) & \(\Delta_{m,t}\) \\  & **(kN)** & **(mm)** & **(kN)** & **(mm)** \\ \hline FW-1 & 137.65 & 51.75 & 169.19 & 68.58 \\ FW-2 & 152.31 & 58.32 & 195.15 & 89.13 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Characteristic values on hysteresis curves.  
Figure 15: Skeleton curves of FW-1 and FW-2.
## 3 Results and Discussion
### Batch Production  
All of the comments from the hospital on the functionality of the prototypes were analysed, as shown above (Table 4). It was decided to introduce final modifications and start the production of a series of adapters in version 4 using the SLS technology. This technology was selected as the target production method corresponding to the indicated demand. The same approach can also produce air-tight elements and the problem of sharp edges is eliminated.  
Figure 6: Timeline of the designing and prototyping process.  
Figure 7: Face mask, mask filter adapter prototype (version no. 1), and DAR filter. (**a**) Before assembly; (**b**) after assembly.  
The EOS Formiga P110 device and Magics 24.1 software (Materialize) were used. Since it was not possible to meet the demand in one construction process, due to the working area of the device, the products were made in two batches of 150 pieces each. With this number, the filling density of the working area was 16.39%, which does not generate the risk of local heat accumulation (Figure 8).  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{Adapter feature}} & \multicolumn{1}{c}{\multirow{2}{*}{Version 1}} & \multicolumn{1}{c}{\multirow{2}{*}{Version 2}} & \multicolumn{1}{c}{\multirow{2}{*}{Version 3}} & \multicolumn{1}{c}{\multirow{2}{*}{Version 4}} \\  & & & & \\ \hline Part volume [cm\({}^{3}\)] & 16.52 & 17.11 & 21.93 & 18.03 \\ \hline Weight [g] & 15.36 & 15.91 & 20.39 & 16.77 \\ \hline Printing time net [h] @ no. of parts & 00:45 @ 14:55 @ 25 & 00:47 @ 11:55 @ 20 & 01:03 @ 13:45 @ 16 & 27:00 @ 150 \\ \hline Price per part (comparatory) & \$\$ & \$ & \$ & \$ \\ \hline Comfort of usage & very low & low & moderate & high \\ \hline Recommended number of parts per process [pcs] & 25 & 20 & 16 & 150 \\ \hline Material & ABS & ABS & ABS & PA12 \\ \hline Method & FDM & FDM & FDM & SLS \\ \hline Sterilisation & possible & possible & possible & possible \\ \hline Postprocess required & support dissolving & support dissolving & support dissolving & abrasive blasting \\ \hline Part dimensions [X \(\times\) Y \(\times\) Z mm] & 40.2 \(\times\) 40.2 \(\times\) 20.0 & 45.3 \(\times\) 45.3 \(\times\) 20.0 & 47.2 \(\times\) 47.2 \(\times\) 25.0 & 47.9 \(\times\) 47.9 \(\times\) 20.0 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Comparison of the design versions of the adapter from the prototype to the finished product.  
Figure 8: Three-dimensional model arrangements in the working space of SLS (Formiga P110): (**a**) Isometric view; (**b**) top view.  
The adapters were produced with a layer height of 0.1 mm. The designed manufacturing technology included 27 h of build time and time related to preparatory and finishing activities, giving a total time of 55 h per batch (Figure 9).  
The production of the second batch followed the same pattern, and started on the day following the completion of the delivery. The second production batch allowed hospital workers to have two adapters per mask. The final adapter, version 4, is presented in Figure 10.
# LPWAN-Based Vehicular Monitoring Platform with a Generic IP Network Interface
## 6 Results
We have validated its operation, extracting OBD parameters from regular cars and GPS, showing its usefulness for such applications as fleet management or monitoring and prediction of vehicle malfunction. A low-power communication device is used as a modem and, although our on-board application is hosted by a regular laptop, our system shows an enormous potential to create embedded devices to monitor a wide range of vehicles, including power-constrained ones such as motorbikes, or even personal mobility vehicles such as bikes and scooters. This currently an on-going study, that plans to extend our work in the area [33]. Additionally, by tuning LoRa communication parameters, it is possible to reduce the data rate in favour of extending the coverage. This could be highly beneficial when large areas must be monitored using IoT communications. In any case, our deployment shows good performance at locations 1.5 km away from the gateway with the considered configuration, which means that at least an area of 7 km\({}^{2}\) could be efficiently covered. In the same way, this tuning could be also applied to cover crowded areas, such as urban zones, with the aim of supporting more terminals at the expense of reducing the coverage area. Nevertheless, it is important to remark that LPWAN technologies can provide concurrent connectivity to many devices but with some limitations, given that they have emission restrictions determined by the unlicensed band duty cycles that prevent devices from flooding the network. In this line, additional work is necessary in order to estimate the number of vehicles that can be covered by a single LPWAN gateway without collision or interference-related issues. In order to face this challange, depending on the LPWAN technology employed, different solutions may be applied, such as employing different LoRa SF in the end-devices, time synchronization techniques such as in Narrow Band-Internet of Things (NB-IoT), and so on. Figure 10: OBD and GPS speed.
## 4 Experimental Comparison and Analysis
### How PAR and F Change  
In this paper, the concept of a learning period for _PAR_ and \(F\) adjustment is adopted, which is computed with the weighted Lehmer mean. It aims to reduce the dependence on the parameters and enlarge the application scope of the algorithm. The results of _PAR_ and \(F\) are recorded in 30 independent runs with the same four functions as the previous sections. Figures 3 and 4 illustrate the changing trends of the adaptive adjustment strategy for _PAR_ and \(F\).  
It is observed that the overall changing trend of the scaling factor \(F\) for four functions is opposite to the parameter \(PAR\). \(F\) is small at the beginning stage of iteration, at about 0.3. However, it becomes large at the latter iteration, probably around 0.9. It is worthy of note that the initial value of \(F\) is 0.5. Therefore, it can be roughly inferred that algorithm is not sensitive to the initial value of \(F\). The possible reason for the four functions with similar trends is that the difference vector of the improving direction guided by DE operation is relatively large at the early generations. Therefore, a relatively small scaling factor \(F\) is suitable to the search demand for the algorithm. On the contrary, most of the solutions approximate to the optimal solution and the difference vector of improving direction is relatively small at the latter generations. Therefore, a large scaling factor \(F\) is required. In addition, although the overall changing trend of each function is similar, the adaptive adjustment behavior of \(F\) still depends on the solving problems. The curves, showing how \(F\) changes for four functions, exhibit different varying principles.  
In this paper, the weighted Lehmer mean is used to adaptively tune \(PAR\) and scale the parameter \(F\). It is a versatile and efficient automatic parameter tuner and is highly successful in tuning search and optimization algorithms [42].
###### Abstract  
It is of great significance for the global navigation satellite system (GNSS) service to detect the polar ionospheric total electron content (TEC) and its variations, particularly under disturbed ionosphere conditions, including different phases of solar activity, the polar day and night alternation, the Weddell Sea anomaly (WSA) as well as geomagnetic storms. In this paper, four different models are utilized to map the ionospheric TEC over the Arctic and Antarctic for about one solar cycle: the polynomial (POLY) model, the generalized trigonometric series function (GTSF) model, the spherical harmonic (SH) model, and the spherical cap harmonic (SCH) model. Compared to other models, the SCH model has the best performance with \(\pm 0.8\) TECU of residual mean value and \(1.5\)-\(3.5\) TECU of root mean square error. The spatiotemporal distributions and variations of the polar ionospheric TEC are investigated and compared under different ionosphere conditions in the Arctic and Antarctic. The results show that the solar activity significantly affects the TEC variations. During polar days, the ionospheric TEC is more active than it is during polar nights. In polar days over the Antarctic, the maximum value of TEC always appears at night in the Antarctic Peninsula and Weddell Sea area affected by the WSA. In the same year, the ionospheric TEC of the Antarctic has a larger amplitude of annual variation than that of the TEC in the Arctic. In addition, the evolution of the ionization patch during a geomagnetic storm over the Antarctic can be clearly tracked employing the SCH model, which appears to be adequate for mapping the polar TEC, and provides a sound basis for further automatic identification of ionization patches.  
Keywords:global navigation satellite system (GNSS); total electron content (TEC); polar ionosphere; spherical cap harmonic (SCH) model; ionization patch +
Footnote †: journal: Sensors
# Development and Testing of an Active Noise Control System for Urban Road Traffic Noise
## 6 Conclusions  
A thorough analysis of the characteristics of various types of road traffic noise was conducted in this study, culminating in the successful development of a prototype for an active noise control system specifically targeting road traffic noise. Active noise control tests were performed in a lab environment, and the results indicated that the system could effectively reduce single-frequency and dual-frequency noise. This suggests innovative ideas and strategies for the application of active noise control technology in road traffic noise management. The main findings are as follows:  
(1) Field traffic noise tests were conducted using a self-assembled noise collection and analysis system. The type and speed of vehicles were found to significantly impact the overall traffic noise produced. However, the mixed traffic noise typically lies within the range of 50-80 Hz, 200-315 Hz, and 800-1250 Hz.  
(2) For different types of vehicles, when the speed exceeds 40 km/h, the traffic noise generated by small vehicles is concentrated around 1000 Hz, medium vehicles around 500 Hz, and large vehicles around 63 Hz.  
(3) An active noise control prototype system based on a FPGA was constructed, and single-frequency and dual-frequency noise reduction tests were performed. The noise reduction effect was found to be satisfactory for single-frequency noise. When the noise frequency was 500 Hz, it could be reduced by nearly 30 dBA. For dual-frequency noise, at 200 Hz + 1000 Hz, a reduction of 15 dBA was achieved.  
**Author Contributions:** All authors contributed significantly to the work presented in this manuscript. [PERSON], [PERSON] and [PERSON] designed and performed the experiments; [PERSON], [PERSON], [PERSON] and [PERSON] analyzed the data and wrote this manuscript; [PERSON] and [PERSON] provided valuable advice and contributions. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was supported by the Technology Innovation and Demonstration Project of the Department of Transport of Yunnan Province (2021) no. 25, funded by the Department of Transport of Yunnan Province. This work was also supported by the National Natural Science Foundation of China (no. 52208414).  
**Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to the confidentiality requirements of the project.  
**Conflicts of Interest:** Author [PERSON] was employed by the company Zhaotong Highway Investment Development Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
# Structural Hierarchy-Enhanced Network Representation Learning
## 4 Experiments
### Experimental Setup  
**Data and Settings.** We use three benchmark network datasets for the experiments, including Cora, Citeseer, and PudMed ([[https://linqs.soe.ucsc.edu/data](https://linqs.soe.ucsc.edu/data)]([https://linqs.soe.ucsc.edu/data](https://linqs.soe.ucsc.edu/data))). Cora data contain 2708 nodes, 5429 edges, and 7 labels, Citeseer has 3312 nodes, 4715 edges, and 6 labels, and PudMed contains 19, 717 nodes, 44, 338 edges, and 3 labels. We evaluate SHE-NRL on two well-known NRL models, DeepWalk (DW) [1], node2 vec (n2v) [3], and LINE [2]. Two competing methods are employed. They are the state-of-the-art hierarchical NRL methods, HARP [7] and Marc [8]. Both construct hierarchical structures for NRL. The embedding dimension of all methods is set \(k=128\). Note that since there are \(\tau\) levels in a method, the embedding dimension of a level graph's NRL is \(\frac{k}{\tau}\).  
**Evaluation Tasks.** We evaluate the effectiveness of node embeddings on two downstream tasks, node classification (NC) and link prediction (LP). Given a certain fraction of nodes and all their labels, the goal of NC is to classify the labels for the remaining nodes. Node embeddings are treated as features. We utilize one-vs-rest logistic regression classifier with L2 regularization as the classifier. The default ratio of training and test is 80:20%. In our main experiment, we will vary the ratio of training and testing to see how different methods perform. On the other hand, LP is to predict the existence of links, given the existing network structure. We need to have the feature vectors of links and non-links. We follow node2 vec [3] to employ Hadamard operator, i.e., element-wise product, to generate the feature vectors from the embeddings of node pairs. To obtain links, we remove 50% of edges chosen randomly from the network while ensuring that the residual network is connected. To have non-links, we randomly sample an equal number of node pairs without edges connecting them.  
**Evaluation Metrics.** For node classification, we consider Macro-F1 (MAF) and Micro-F1 (MIF) as the evaluation metrics. For link prediction, we utilize Area Under Curve (AUC) scores. Higher values indicate better performance in all metrics. Note that due to page limit, we report only MAF for node classification while MIF exhibits very similar results.
# Implementation of Constrained Swept Synthetic Aperture Using a Mechanical Fixture
## 4 Discussion
There are several computational challenges to address for clinical implementation of the constrained SSA approach. First, the current multi-lag displacement estimation approach used in this paper requires all images in the sequence before estimates are made and available for beamforming. A local estimator (or even estimates from individual image pairs) could be used instead so that beamforming could begin during data acquisition for more rapid results. Beamforming itself presents a challenge in that time delays need to be recalculated for each observed array position relative to the target pixel grid. As a downsampling of acquired frames for beamforming is already implemented, it may be possible to strategically choose these samples to align with precomputed array positions to avoid recalculating delays, although slight position error may result. Finally, over a one second sweep, an operator will be left without live image guidance in the proposed approach. It should be possible to beamform the low-resolution frames for guidance or to interleave a short B-mode imaging sequence with the SSA transmissions to provide live guidance images while the high-resolution SSA image is completed. If it is possible to make similar estimates in other dimensions, it may be possible to make SSA a truly freehand technique (i.e., without constrained motion). Estimates in the axial dimension are possible as in flow or elasticity imaging, and 2-D motion estimates are becoming more common using vector flow imaging techniques. However, more research is needed to translate these techniques to the problem of estimation transducer motion. Out-of-plane motion will remain a challenge unless using a matrix array, although it is expected that the lower elevation resolution should also reduce the sensitivity to motion in that dimension.
# Evaluating Litter Yield and Decomposition for Re-Vegetated Mangroves in a Subtropical Mudflat
###### Abstract  
Field monitoring and incubation experiments were conducted to evaluate the litter yield and examine the decomposition of the litter of three representative mangrove species frequently used for mangrove re-vegetation in a subtropical mudflat on the South China coast. The results show that the litter yield of the investigated mangrove species varied significantly from season to season. The annual litter production was in the following decreasing order: _Heritiera litteralis \(>\) Thesesia populnea \(>\) Kandelia obovata_. Initially, rapid decomposition of easily degradable components of the litter materials resulted in a marked weight loss of the mangrove litter. There was a good linear relationship between the length of field incubation time and the litter decomposition rate for both the branch and the leaf portion of the three investigated mangrove species. Approximately 50% or more of the added mangrove litter could be decomposed within one year and the decomposed litter could be incorporated into the underlying soils and consequently affect the soil carbon dynamics. An annual soil carbon increase from 2.37 to 4.64 g/kg in the top 5 cm of the soil was recorded for the investigated mangrove species.  
Keywords: mangrove; litterfall; litter decomposition; soil carbon sequestration; subtropical coast +
Footnote †: journal: Applied Sciences
## 2 Materials and Methods
### Data Processing
#### 2.4.3 Analysis of Control-Free-Image Accuracy  
To explore the feasibility of control-free-image-based nap-of-the-object photogrammetry in monitoring Benggang, 10 ground checkpoints were installed parallel to the course within the Benggang study area. The coordinates were collected through the RTK network's CORD mode, then compared with measured coordinate values extracted from the UAV images for the corresponding ground checkpoints. As per Formula (1), the horizontal X-coordinate error of the GCP can be expressed as \(\Delta\)x; the horizontal Y-coordinate error, as \(\Delta\)y; the elevation Z error, as \(\Delta\)z; and the planar direction X Y error, as \(\Delta\)xy. The measured coordinates of the ground checkpoint are denoted by M (xi, yi, zi), and the computed coordinates of the ground checkpoint are denoted by C (x'i, y'i, z'i).  
The planar and elevation coordinates, labeled similarly, were obtained through nap-of-the-object photogrammetry acquisition as DOM image data and DSM data and were then extracted through ArcMAP software to create a model corresponding to the measured coordinate points, which were calculated as 3D coordinates (X, Y, Z) coordinate data. Formula (2) was used to determine the root mean square error (RMSE), or \"medium error\", of the GCP position. Measurement accuracy was then defined according to the error data from the DOM image and DSM.  
\[\Delta\mathrm{x}\ =\ \mathrm{xi}-\mathrm{x^{\prime}i};\ \Delta\mathrm{y}= \mathrm{yi-y^{\prime}i};\ \Delta\mathrm{z}\ =\ \mathrm{zi-z^{\prime}i};\ \Delta\mathrm{xy}\ =\ \sqrt{\left(\mathrm{xi-x^{\prime}i}\right)^{2}+\left(\mathrm{yi-y^{\prime}i} \right)^{2}} \tag{1}\]  
\[\mathrm{M}  
value of the ground checkpoints in m; and n represents the number of ground checkpoints used for accuracy assessment.
# Resource Allocation for Relay-Based OFDMA Power Line Communication System
###### Abstract  
In this paper, we investigate the resource allocation for multi-user orthogonal frequency division multiple access (OFDMA) power line communication (PLC) systems, which satisfy both the total average transmit power constrained by PLC networks and the required interference limitations. First, we propose an optimal resource allocation scheme, with respect to joint consideration of the subcarrier and power constraint to maximize the throughput of the PLC system. Then, we divide the intractable problem into two individual subproblems to decrease the computational burden, which can avoid proceeding the mixed integer nonlinear programming (MINLP) problem. The proposed resource allocation scheme can ensure the optimality and efficiency of the system with rigorous proofs. The simulation results show that our proposed resource allocation scheme for the PLC system outperforms other algorithms, and is efficient with acceptable complexity.  
joint optimization; orthogonal frequency division multiple access (OFDMA); power line communication (PLC); resource allocation +
Footnote †: journal:  
_Article_  
Resource Allocation for Relay-Based OFDMA Power Line Communication System