esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 FPGA-Based Real-Time Simulator Architecture
This is mathematically expressed in the form of a sum of product (SOP)  
\[x(i)=\sum_{j=1}^{M}A^{-1}(i,j)b(j) \tag{4}\]  
where \(i=1,2,\ldots,M\). The \(M\) SOP equations of Equation (4) are independent from one another and therefore they can be solved in parallel. This constitutes one level of parallelism which is at the equations level. The multiplication operations involved in the computation of the SOP of Equation (4) are independent and  
Figure 3: (**a**) Switch; (**b**) ADC switch model. can be carried out in parallel. This constitutes a second level of parallelism which is at the level of \"primitive operations\". The computational engine is designed such that it has a massively parallel hardware architecture that exploits these two levels of parallelism. Figure 4 shows the functional diagram of the proposed hardware architecture implemented inside the FPGA-based real-time simulator. The module has three main building blocks:  
* the first building block is responsible for calculating the node voltages, and
* the second and third building blocks are responsible for updating the history current sources associated with switching and non-switching elements, respectively. Figure 4: Functional diagram of the computational engine. It has to be noted that in this scheme the matrix-vector multiplication of Equation (3) is actually performed based on utilizing \(n^{2}\) parallel multipliers. As shown in Figure 4, the design has \(n\) parallel voltage processing elements. Each processing element is responsible for evaluating the voltage at a given node. Within each processing element, there are \(n\) parallel multipliers and an adder tree. The history current sources are updated in parallel in a similar manner. Each history current source equation is assigned to a dedicated current processing element. Within each processing element, there are a number of parallel multipliers and an adder tree. Moreover, a current processing element for switching devices has additional control circuitry to determine the ON/OFF states of the switching element based on internal variable, _i.e._, voltage across the switch and/or current through it, or external control signals if it is controllable. In massively parallel architectures, communication and synchronization among processing elements play a vital role in determining the overall system performance. Improper communication and synchronization schemes result in large overhead time that can severely limit the overall system performance. In this work, to minimize the communication and synchronization overhead times, a unidirectional point-to-point static interconnection network is implemented such that the data can be transferred directly from the outputs of one processing element to the inputs of another one. The whole design, _i.e._, the processing elements and the interconnection network, is operated in a synchronous mode with a global clock controlling both the computations and the dataflow.
###### Abstract  
This study discussed the mechanism of Fe-modified biochar (FeBC) derived from rice straw biochar (BC) as an adsorbent for removing Cr(VI) from aqueous solution and assessed its applicability in actual industrial wastewater. The Cr(VI) removal percentage increased with the FeBC dose, which achieved a removal of 99.5% at 8.0 g/ L FeBC. Increasing the solution pH from 2 to 10 slightly reduced Cr(VI) adsorption by 6.6%. Coexisting ions such as Ca\({}^{2+}\), Na\({}^{+}\) and Cl\({}^{-}\) inhibited the removal of Cr(VI); the removal rate decreased to 60% at their concentration of 0.25 mol/L. The adsorption isotherm and kinetics were better described by the Langmuir isotherm and pseudo-second-order kinetic models, respectively. Through scanning electron microscopy with energy dispersive X-ray, the Brunauer-Emmett-Teller method, Fourier transform infrared, X-ray diffraction and X-ray photoelectron spectroscopy, the analysis revealed that FeBC with iron oxides loaded onto its surface had more active sites than BC; the surface functional groups changed; the removal of Cr(VI) by FeBC was mainly attributed to electrostatic adsorption; the redox reaction of Cr, and Fe loaded onto BC enhanced Cr(VI) reduction process. FeBC showed a good removal performance on actual industrial wastewater with the concentration of both total Cr and Cr(VI) meeting the integrated wastewater discharge standard of China.  
ferric nitrate; modified biochar; adsorption; hexavalent chromium; industrial wastewater
# Phase Balancing and Reactive Power Support Services for Microgrids
## 2 Microgrid Architecture
### Energy Storage  
The implementation of a flexible microgrid requires the existence of an ESS, which will absorb or provide energy according to the energy needs of the MG. Therefore, an energy storage system of 50 kW and with a usable capacity of 100 kWh is considered to be located in Block D.
## 2 Previous Studies
### Radio Telescopes
The non-uniformity of the Shanghai 65 m Radio Telescope's temperature filed under solar radiation is reflected in the back-up and reflector structure, and the non-uniform structural temperature deformation leads to the geometric shape of the telescope during its service period being different from its designed shape, resulting in possible observation errors [82]. The solar cooker effect refers to the phenomenon of sunlight gathering on the main reflector and subreflector, which can cause rather high temperatures, and huge temperature deformations in localized positions on the reflector [83]. Based on finite element analysis, the maximum temperatures of the main reflector and subflector of the Shanghai 65 m Radio Telescope under solar radiation were up to 44.5 \({}^{\circ}\)C and 144.9 \({}^{\circ}\)C during the daytime, indicating that the solar cooker effect on the subreflector is more significant and nonnegligible [84]. Thus, on the basis of an analysis of these results, unfavorable working states and times should be avoided as much as possible in the process of radio observation when using movable radio telescopes [85]. In addition, the temperature fields and effects of other movable radio telescopes have also been studied through the use of measurements or simulations, including the RT-70 Telescope [86], the Green Bank Telescope [87], and the Nobeyama 45 m Telescope [88; 89]. Aperture synthesis radio telescopes, which consists of several fixed and movable radio telescopes, not only provide a large signal receiving area, but also avoid the construction difficulties of large-aperture radio telescope; these include the Square Kilometer Array [90] and the Atacama Large Millimeter/submillimeter Array [91]. [PERSON] measured the temperature field of the main reflector and subreflector of one 3 m aperture radio telescope model continuously for two months [92; 93], the experimental results showed that the solar cooker effect and non-uniform temperature distribution of the main reflector and subreflector were also remarkable even for small aperture radio telescopes, implying that temperature deformation and surface precision error cannot be ignored. The large number of radio telescopes that make up synthetic aperture telescopes may be under different working states, where the superposition effect of possible observation errors caused by thermal deformation could be considerable. To summarize, experimental and numerical studies show that the temperature field of radio telescopes under solar radiation is obviously non-uniform, and the corresponding solar cooker effect is also nonnegligible; the temperature deformation caused by non-uniform temperature variation can directly affect the surface precision and pointing precision of radio telescopes, resulting in possible observation errors. To ensure the observation accuracy, important observation tasks should be carried out at appropriate working times, and avoiding unfavorable working states of the radio telescope; meanwhile, the adoption of some effective measures have also been suggested, such as enhancement of ambient air flow [94].
# Research on Hybrid Relay Protocol Design and Cross-Layer Performance Based on NOMA
## 1 Introduction
This paper compares the cross-layer performance of the system under different transmission schemes such as NOMA, OMA, and wireless single-hop, and analyzes the law of the influence of physical layer parameters and MAC layer parameters on system performance. The simulation results verify the validity and reliability of the theoretical model and show that the best power allocation algorithm in this paper makes the system have better performance in terms of normalized throughput, packet loss rate, and delay. The rest of this study can be summarized as follows: Section 2 introduces the system model of this paper. Section 3 introduces the design of MAC layer transport protocol for two-hop relay system based on NOMA and establishes the cross-layer performance analysis model. Section 4 gives the simulation results. The combined optimization of the \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Ref.** & **Year** & **Major Focus** & **Optimization Objective and Performance** \\ \hline
[4] & 2022 & Hybrid TDMA-NOMA system. & Joint allocation of available time slots and available transmit power in hybrid TDMA-NOMA systems to maximize energy efficiency. \\ \hline
[6] & 2023 & Hybrid wireless and power line communication systems. & A power allocation optimization technique is proposed to achieve an outage-optimal performance. \\ \hline
[8] & 2023 & A long-term cross-layer resource allocation model with dynamic traffic arrivals and limited channel information. & Minimizes long-term average total power consumption while meeting QoS requirements. \\ \hline
[9] & 2021 & Cloud Radio Access Network (C-RAN) based on NOMA. & Maximize energy efficiency by jointly optimizing power distribution, analog and digital precoding. \\ \hline
[10] & 2021 & NOMA system with delay requirements. & Get the best delay power trade-off in NOMA systems \\ \hline
[13] & 2021 & Unmanned Aerial Vehicle (UAV) Assisted & A cross-layer resource allocation strategy including UAV scheduling, number of grouped users and power allocation is proposed to reduce file interrupt probability and improve hit probability. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of existing research in the last three years. source transmit power and the power distribution factor between users is carried out for the system in Section 5. Section 6 summarizes the work of this paper.
# Balanced Loss Function for Accurate Surface Defect Segmentation
## 2 Method  
### Preliminaries  
In this subsection, we define the notations of the variables involved in the computation of segmentation loss function, as summarized in Table 1. These notations are used throughout this paper. Other notations involved in the derivation of the balanced loss function are defined in the corresponding subsections.  
A segmentation model makes a segmentation prediction as a three-dimension tensor \(Y\in\mathbb{R}^{+W\times H\times C}\), where \(W\) and \(H\) are the width and the height of the image, and \(C\) is the number of class. The background class, if applied, is also included in \(C\). At each point, the output vector is a valid posterior probabilistic prediction, i.e., \(\forall 1\leq i\leq W,1\leq j\leq H,\sum_{k=1}^{C}Y_{i,j,k}=1\). This is normally achieved by a soft-max operation on neural network output.  
The pixel-level annotation of an image of size \((W,H)\) is a matrix \(A\in\mathbb{N}^{W\times H}\), where each entry is in \(\{1,2,...,C-1,C\}\), representing the defect class of the point. For convenience, we also introduce the one-hot encoding of \(A\), which is a tensor \(\hat{Y}\in\mathbb{R}^{W\times H\times C}\). At any point \((i,j)\), if \(A_{i,j}=c\), then \(\hat{Y}_{i,j,c}=1\) and other entries have \(k\
eq c\Rightarrow\hat{Y}_{i,j,k}=0\).  
At last, a segmentation loss function \(f:\mathbb{R}^{W\times H\times C}\times\mathbb{R}^{W\times H\times C}\to \mathbb{R}^{+}\) always outputs a positive value that measures the dissimilarity of the prediction \(Y\) and the label \(\hat{Y}\).
# A Low-Light Sensor Image Enhancement Algorithm Based on HSI Color Model
## 4 Experiments Results
### Comparison with State-of-the-Art Methods  
In order to evaluate the proposed method, we use both synthetic and real low-light images. Then the results are compared with HE [29] algorithm and other recent state-of-the-art low-light image enhancement methods such as Dong, SRIE and LIME in terms of subjective and objective criteria.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Layers** & **Filters Numbers** & **PSNR** & **LOE** \\ \hline
5 & \(n_{1}=64,n_{i-1}=32\) & 21.74 & 401 \\
5 & \(n_{1}=64,n_{i-1}=64\) & 21.87 & 394 \\
7 & \(n_{1}=64,n_{i-1}=32\) & 22.23 & 371 \\
7 & \(n_{1}=64,n_{i-1}=64\) & 22.31 & 365 \\
9 & \(n_{1}=64,n_{i-1}=32\) & 22.04 & 3
# Bond Strength Properties of GFRP and CFRP according to Concrete Strength
## 5 Conclusions  
The following conclusions were drawn from the experiment on the bond strengths of GFRP and CFRP by concrete strength based on the scope of the study.  
1. While investigating the relationship between bond strength and slip, bond strength tended to increase after rib failure in the concrete with a 40% water-cement ratio. This can be attributed to the increased bond strength in the remaining intact concrete-rebar ribs under high compressive strength.
2. For all water-cement ratios, it was found that higher the compressive strength of the concrete, the better the adhesion strength between the concrete, and the CFRP or GFRP. This could be attributed to the effect on the increase in strength.
3. When comparing the bonding strength of the GFRP and CFRP, the bonding strength of the CFRP, which has higher tensile strength, was greater than that of the GFRP. This could be attributed to the resistance offered by the reinforcing bar with high tensile strength against the pull-out load even under the same frictional force.  
This experimental study was aimed toward investigating the adhesion strength of GFRP and CFRP at three levels of W/C and the same reinforcement diameter. Other parameters affecting adhesion strength between concrete, and CFRP or GFRP could not be explained through the results of this study. In the future, research on GFRP and CFRP according to the concrete mixing level and rebar diameter ought to be investigated.  
**Author Contributions:** Formal analysis, J.K. and S.J.; experiment, J.K., S.J. and H.K.; writing--original draft preparation, J.K. and S.J.; writing--review and editing, J.K., S.J. and H.K.; visualization, J.K.; supervision, S.P.; project administration, S.P., Y.K. and J.K. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work is supported by the Korea Agency for Infrastructure Technology Advancement (KAIA) grant funded by the Ministry of Land, Infrastructure, and Transport (Grant 22 CFRP-C163390-02).  
**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.  
Figure 16: Fracture shape of the GFRP surface.  
Figure 17: Fracture shape of the CFRP surface.
## 3 Test Results  
### External Earth Pressures  
External earth pressures at the vault, invert, and hance of the main tunnel were monitored. The monitoring section was far away enough from the openings, considered not to be affected by the openings. The external earth pressure results can provide a reference for external loads on the tunnel in the process of structural design or theoretical analysis.  
Variations of the earth pressures versus time at three different positions under three different buried depths are plotted in Figure 9.  
As the centrifuge accelerated level by level, the earth pressures increased and showed obvious step variations versus test time. When the acceleration reached the design value for each level, the earth pressure would gradually tend to be stable and the values after stabilization for each acceleration level are extracted. In addition, it can be found that the greater the buried depth, the longer the time required for the stability of the earth pressure results.  
The vertical earth pressures at the tunnel vault under 50 g acceleration of the three buried depths, namely, 1.0 D, 1.5 D, and 2.0 D, are 226.4 kPa, 292.1 kPa, and 364.3 kPa, respectively, while the theoretical values of earth pressures considering the whole soil column are 244.6 kPa, 366.8 kPa, and 489.1 kPa. It shows that the vertical earth pressures at the vault are smaller than the theoretical values, and the reduction coefficients are 0.926, 0.796, and 0.74, respectively, indicating that a certain soil arching effect has occurred in the soil above the tunnel. Moreover, the reduction coefficient of the vertical earth pressure at the tunnel vault gradually decreases with the increase of buried depth. The reason can be speculated that, with the increase of buried depth, the load on the tunnel increases, and the elliptical deformation trend is amplified, resulting in a more significant arch effect of the overlying soil.  
The lateral earth pressures at the tunnel hance under 50 g acceleration of the three buried depths, namely, 1.0 D, 1.5 D, and 2.0 D, are 89.7 kPa, 112.1 kPa, and 143.8 kPa, respectively. Thus, the lateral pressure coefficients corresponding to the vertical earth pressure of the whole soil column are 0.245, 0.229, and 0.235, respectively. In practical engineering, as the elliptical deformation trend will be amplified due to the increase of the buried depth, the soil close to the tunnel hance will be squeezed to a certain extent, resulting in passive earth pressure, and the lateral earth pressure coefficient may increase to a certain extent. However, in the tests, the three lateral pressure coefficients were consistent. This is because, in the scaled model tests, the lateral expansion displacement of the tunnel was limited, and the passive earth pressures caused were relatively small, so the monitored lateral pressure coefficients were consistent.  
Figure 8: Photos of the model tunnel: (**a**) laser sensors and support; (**b**) model tunnel in soil box.  
Figure 9: Variations of earth pressures versus test time: (**a**) 1.0 D, (**b**) 1.5 D, (**c**) 2.0 D.
# Cyclostationary Crosstalk Cancelation in High-Speed Transmission Lines  
[PERSON]  
Theoretical and experimental evaluation of the cyclostationary random data transferring process corrupted by the individually and jointly cyclostationary crosstalk interference is presented. The interference and the message signals were measured by the real time digital oscilloscope. Autocorrelation functions were evaluated by synchronous cyclic averaging procedure. The analyzed periodic two-dimensional impulse response of the time-varying filter allows to obtain the output random process with the same cyclic frequency at the output of the filter by separation of orthogonal stationary waveforms constituting the input cyclostationary random process (CSRP). The filtering of the measured random process was implemented by the cyclic Wiener filter. The evaluation of the two-dimensional autocorrelation function and eye diagrams at the output of the cyclic Wiener filter showed significant reduction of the independent interference components in the estimated message signal.
## 3 Results and Discussion
### Comparative Analysis on Two Feature Fusion Strategies
_subterruneus_ species, the prediction results of the serial fusion strategy had a 97.5% probability of significant improvement over the parallel fusion strategy. In the _A. thaliana_ species, _E. coli_ species, and _G. pickeringi_ species, the prediction results of the serial fusion strategy had a 99% probability of significantly improvement over the parallel fusion strategy.
## 2 Materials and Methods
### Transformer
The outputs of all heads are concatenated and linearly transformed to form the final attention output. Following the attention block, each encoder layer includes a fully connected FFNN, which is applied independently to each token and consists of two linear transformations separated by a rectified linear unit (\(ReLU\)) activation function. This is expressed in Equation (5):  
\[FFNN\ (\mathbf{x})=max(0,\ \mathbf{xW_{1}},+\mathbf{b_{1}})\mathbf{W_{2}}+\mathbf{b_{2}} \tag{5}\]  
where \(\mathbf{x}\) is the input vector corresponding to a single token or position in the sequence, \(\mathbf{W}\) is the weight matrix, and \(\mathbf{b}\) is bias vector. To facilitate gradient flow and prevent vanishing gradients, residual connections are added around each sub-layer, and the result is normalized using layer normalization. The encoder output is passed to the decoder, which mirrors the encoder's structure but includes an additional attention layer at the beginning of each decoder block. As shown on the right-hand side of Figure 1, the decoder receives the output sequence shifted by one position and first applies masked multi-head attention. This masking ensures that each position can only attend to earlier positions in the sequence, thereby preserving the auto-regressive property necessary for sequence generation. After masking, the decoder performs another multi-head attention operation, this time over the encoder's output. This cross-attention enables the decoder to align its predictions with relevant parts of the input sequence, effectively capturing dependencies between input features and output decisions. The decoder output is finally passed through a linear transformation followed by a softmax activation to produce a probability distribution over the output classes. For classification tasks such as intrusion detection, this output corresponds to predicted class probabilities for each input sequence. This final step is formalized in Equation (6) [39]. \[\hat{Y}=softmax(HW_{c},+b_{c}) \tag{6}\]  
where \(H\) denotes the final decoder representation, \(W_{c}\) is the classification matrix, and \(b_{c}\) represents the predicted probabilities for each class.
## 2 Materials and Methods
### Description of Gas Analysers
#### 2.1.4 Gasmet  
The Gasmet CX4000 is a multi-gas analyser based on FTIR. The analyser performs interferometry using a narrowband laser to construct transmittance and absorption spectra over the 900-4200 cm\({}^{-1}\) mid-infrared region, and the 910-1150 cm\({}^{-1}\) region is used to estimate NH\({}_{3}\) concentrations that are based on the Beer-Lambert law. Measurements were taken at 180 \({}^{\circ}\)C around atmospheric pressure regulated automatically by the instrument. The Gasmet system consisted of two separate units. During measurement, the air samples sequentially flowed through a sampler unit and an analysing unit. In order to minimize the temperature difference between the incoming air samples and the analyser measurement cell, a 10 m heated hose was attached to the inlet of the sampler unit. An automated zero-calibration was performed daily while using a dry nitrogen gas. Interference from water vapour and carbon-dioxide were known to the manufacturer and were compensated in the CalcmetTM Analysis and Controlling Software offered by the manufacturer.