esa-sceva/satcom-chunk-collection huggingface dataset:
###### Abstract  
The aim of this study is to evaluate the feasibility and usefulness of the human umbilical cord mesenchymal stem cells (hUC-MSCs) and hyaluron acid (HA) combination to attenuate osteoarthritis progression in the knee while simultaneously providing some insights on the mitigation mechanism. In vitro, the effect of hUC-MSCs with HA treatment on chondrocyte cell viability and the cytokine profile were analyzed. Additionally, the antioxidant capability of hUC-MSCs-CM (conditioned medium) with HA towards H\({}_{2}\)O\({}_{2}\)-induced chondrocyte cell damage was evaluated. The HA addition increased the hUC-MSC antioxidant capability and cytokine secretion, such as Dickkopf-related protein 1 (DKK-1) and hepatocyte growth factor (HGF), while no adverse effect on the cell viability was observed. In vivo, the intra-articular injection of hUC-MSCs with HA to a monoidoacetate (MIA)-induced knee osteoarthritis (KOA) rat model was performed and investigated. Attenuation of the KOA progression in the MIA-damaged rat model was seen best in hUC-MSCs with a HA combination compared to the vehicle control or each individual element. Combining hUC-MSCs and HA resulted in a synergistic effect, such as increasing the cell therapeutic capability while incurring no observable adverse effects. Therefore, this combinatorial therapy is feasible and has promising potential to ameliorate KOA progression.  
antioxidation; DKK-1; hyaluron acid; mesenchymal stem cell; osteoarthritis
# The Development of a Spaceborne SAR Based on a Reflector Antenna
## 4 Challenges and Development Trends in Reflector Antenna-Based SAR Technology
### Emerging Techniques for Reflector Antenna-Based SAR
#### 4.1.1 Reflector Antennas with DBF
By incorporating the DBF technique, reflector antenna-based SAR systems can achieve HRWS imaging while reducing the complexity of large-aperture beamforming processors, improving overall system efficiency [69]. Compared to conventional planar phased array DBF SAR systems, reflector antenna-based DBF SAR systems offer several advantages:  
(1) Lower Weight, Simpler Structure and Cost-Effectiveness--For a given aperture and gain, reflector antennas are generally lighter and structurally simpler, making them well suited for large-scale, spaceborne HRMS SAR systems. (2) Larger Aperture Capabilities--Reflector antennas can accommodate larger apertures, resulting in higher resolution and gain. When combined with DBF, they enable flexible beam scanning and multi-beam imaging, thereby extending the swath width while maintaining a high resolution. Thus, the integration of reflector antennas with the DBF technique represents a revolutionary advancement in spaceborne SAR systems, enhancing system gain, efficiency, beam control, and multi-beam imaging. This breakthrough overcomes the performance limitations of traditional SAR systems, paving the way for more efficient, flexible, and cost-effective HRMS SAR. Building on these performance advantages, reflector antenna-based DBF SAR systems also exhibit strong potential for next-generation wide-swath and high-resolution Earth observation missions. DBF applied to reflector antennas offers promising capabilities for future ultra-wide-swath, high-resolution SAR systems, such as those envisioned in Tandem-L-like missions. The combination of DBF with reflector antennas allows for flexible beam control and supports various imaging modes. Nevertheless, implementing DBF with reflector antennas also introduces signal processing complexities that must be carefully addressed. The far-field pattern of reflector antennas must be simulated accurately, requiring precise modeling of the feed reflector geometry. Unlike planar phased arrays that are often approximated by simple sinc patterns, reflector antennas require more complex electromagnetic modeling. Furthermore, due to the echo path involving reflection before reaching the feed, the signal model becomes more complicated, and conventional DBF weight generation methods are often inadequate. Overall, reflector antenna-based DBF systems offer a powerful and scalable approach to overcoming traditional SAR limitations, marking a critical step forward in the evolution of high-performance spaceborne SAR system.
## 2 A Framework of a Remote Sensing-Based Ecosystem Health Assessment  
The spatially explicit nature of remote sensing data with frequent revisit cycles provides an opportunity to assess and monitor the spatial heterogeneity of ecosystem health. Nonetheless, concerns were raised that remote sensing specialists may pay more attention to technology than ecological problems [29,30], while ecologists may not have sufficient remote sensing background to address ecological problems at local to global scales [25]. Efforts thus are needed to bridge the research gap between the two research communities.  
To develop a comprehensive remote sensing-based EHA system, one might follow the procedures proposed in Figure 1 with the participation of remote sensing experts and ecologists. The cooperation of the experts in both remote sensing and ecology fields allow the effective health indicators to be identified efficiently and make sure that those indicators can be measured by remote sensing data.  
Although Figure 1 includes indirect estimation of health indicators through modeling using remote sensing data as input, this review focuses on the questions we proposed: Q7a: Are there any routine remote sensing products for health indicators? Q7b: What kind of imagery and approach can be used to estimate health indicators, and challenges and future opportunities to develop a remote sensing- based spatially explicit EHA and monitoring system (the ultimate goal presented in Figure 1).
# Adaptive Beamformer Combined with Phase Coherence Weighting Applied to Ultrafast Ultrasound
## 3 Results
### In Vivo Measurement of Human Carotid Artery  
In the present study, the feasibility of the proposed method under in vivo condition was evaluated by measurement of a human carotid artery. Figure 8a-d show B-mode images of the carotid artery obtained by the DAS beamforming, the mAPES beamforming without gPCF, and those with gPCFs estimated before and after applying the adaptive beamformer weights, respectively.  
In Figure 8c,d, the wall of the carotid artery was depicted more clearly and sharpened along the lateral direction than Figure 8a,b.
## 3 Simulations and Results  
Our proposed retrieval method was examined through a series of simulations. We use synthetic DSD fields combined with a realistic LEO satellite communication system to simulate the estimated SNRs. The retrieval results of the specific attenuations and the DSD parameters are compared with their true values.
# Advances in Improving Energy Efficiency of Fiber-Wireless Access Networks: A Comprehensive Overview
## 4 Energy Efficiency Analyses of Radio-over-Fiber Networks
The main difference between the RFoF and the IFoF techniques is in the carrier frequency used for modulation of the optical signal for transmission over a fiber-optical link. In the case of the RFoF technique, the analog signal directly modulates the optical signal, while in the IFoF technique, the signal of intermediate frequency is used for optical signal modulation.
## 2 Theoretical Research on Indirect Measurement Method Based on Vehicle-Bridge Coupling
### Theoretical Analysis of Detection Method Based on Vehicle Response
When there is damage somewhere in the bridge and the bridge stiffness decreases, the deflection of the bridge at the damage location is:  
\[f_{z\theta_{d}}=\frac{1}{1-\theta_{d}}\left\{\frac{F_{q}}{EI}\left[ \begin{array} []{c}\left(\frac{(x+\Delta n)^{3}}{6!}+\frac{(x+\Delta n)l}{3}-\frac{(x+\Delta n )^{2}}{2}\right)x\\ -\frac{\left(l-(x+\Delta n)x^{3}\right)}{6l}\end{array} \right]+\frac{F_{c}x^{2 }(x-l)^{2}}{6l}\right\}=\frac{1}{1-\theta_{d}}f_{z}(x) \tag{19}\]  
where \(\theta_{d}\) is the degree of damage to the bridge. The vehicle's body acceleration response at the point of injury is:  
\[a_{v1\theta}=\frac{a_{0}}{b_{2}b_{1}-b_{3}^{2}}\left( \begin{array}{c}b_{1}(b_ {4}+b_{6})+b_{3}(\frac{1}{1-\theta_{d}}c_{w1}f_{z}^{\prime}(x)\\ +\frac{1}{1-\theta_{d}}k_{w1}f_{z}(x)+b_{5}+b_{7})\end{array} \right)-a_{0}u_{ i1}-a_{2}\dot{u}_{i1}-a_{3}\ddot{u}_{i1} \tag{20}\]  
From Equations (18) and (20), it can be seen that the acceleration response of the car body contains bridge deflection and speed response information, and the acceleration response of the car body through the bridge is processed and analyzed, and the bridge information can be identified. When a bridge is damaged, the deflection of the bridge changes accordingly at the location of the damage, and this change will be reflected in the acceleration response of the car body, so the damage location can be identified by using the acceleration response of the car body.
# Person Identification and Gender Classification Based on Vision Transformers for Periocular Images
## 6 Conclusions  
New systems are required in order to identify people with face masks. In biometrics, the methods frequently used, like fingerprint and face recognition technologies, needed an upgrade since a significant portion of the face is covered by the mask. Our proposed solution addresses this issue by utilizing the latest innovations in deep learning, initially applied in NLP, which is also helpful in computer vision. ViT has been shown to give better performance accuracy. In our experiment, the best model was the ViT base model with 16 patches, which provided an accuracy of 98.186, based on the K-fold technique, with K = 5. It has been seen that with smaller patches, there is an improvement in accuracy. In the future, we plan to develop a hybrid technique to address the critical issues of person identification and gender classification.  
Conceptualization, V.K.S.; Methodology, V.K.S.; Software, V.K.S.; Validation, V.K.S.; Formal analysis, V.K.S.; Investigation, V.K.S.; Visualization, V.K.S.; Supervision, H.Y.P.; Project administration, H.Y.P. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
**Data Availability Statement:** The data that support the findings of this study are available from UBIPr Dataset owners (link below), but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however, available from the authors upon reasonable request and with the permission of the UBIPr Database owners. (Link: [[http://iris.di.ubi.pt/ubipr.html](http://iris.di.ubi.pt/ubipr.html)]([http://iris.di.ubi.pt/ubipr.html](http://iris.di.ubi.pt/ubipr.html))).  
**Conflicts of Interest:** The authors declare no conflict of interest.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{\
\begin{tabular}{c} **Experiments on** \\ **the UBIPr Dataset** \\ \end{tabular} } & \multirow{2}{*}{**Models**} & \multicolumn{3}{c}{**CV Score (Accuracy)-ViT Models**} & \multicolumn{1}{c}{**Earlier Results**} \\ \cline{3-6}  & & **Original** & **Improved** & **Train-Val-Test** \\ \cline{3-6}  & & **K-Fold (5)** & **K-Fold (5)** & **6025-1152-3075** & **(6025-1152-3075)** \\ \hline \multirow{4}{*}{
\begin{tabular}{c} **Gender** \\ **Classification** \\ \end{tabular} } & ViT-T/16 & 98.605 & 98.430 & 97.820 & \\ \cline{2-6}  & ViT-B/16 & **99.040** & **99.132** & **98.530** & \\ \cline{1-1} \cline{2-6}  & ViT-S/16 & 98.440 & 98.664 & 98.170 & **95.00**[33] \\ \cline{1-1} \cline{2-6}  & ViT-B/32 & 97.580 & 97.464 & 96.170 & \\ \cline{1-1} \cline{2-6}  & ViT-S/32 & 97.776 & 97.386 & 96.580 & \\ \hline \hline \end{tabular}
\end{table}
Table 3: Gender Classification based on different models.
## 3 Data Analysis Method
### Key Algorithms  
Since the original dataset is derived from the unsteady CFD analysis, the data analysis and mining mainly involve FFT analysis and trigonometric function fitting algorithms.  
FFT is an efficient algorithm for computing the DFT (Discrete Fourier Transform), which is widely used in fields such as digital signal processing. The FFT algorithm is based on the decomposability of DFT. It achieves fast computation by decomposing the DFT of a long sequence into multiple DFTs of short sequences. In this study, a dedicated FFT function named \"FFT_plot_and_export\" is developed using the Decimation in Time (DIT) algorithm. The basic idea is as follows: for a discrete time sequence \(\mathrm{x}[n]\) (\(n=0,1,\ldots,\mathrm{N}-1\)) of length N, assuming N is an integer power of 2, the sequence is first split into two subsequences of length N/2 according to the parity of the time order. Then, with the help of specific rotation factors, the DFT result of the original sequence is represented as a combination of the DFT results of these two subsequences. Subsequently, the parity decomposition operation is repeated on the obtained subsequences until the length of the subsequence becomes 2. Since it is easy to compute the DFT of a subsequence of length 2, the DFT result of the original sequence can be efficiently calculated through such step by step decomposition and computation. The detailed principle of the DIT algorithm can be found in [37].  
The \"Isqcurvefit\" function in MATLAB is used for trigonometric function fitting of the time varying curves of relevant parameters. The maximum number of iterations in the fitting process is set to 10,000, and the convergence tolerance is \(10^{-6}\). The \"Isqcurvefit\" function is used to solve the nonlinear least squares curve fitting problem. Its goal is to find a set of function parameter values that minimize the sum of the squared residuals between the given nonlinear function and the observed data. Specifically, the Levenberg-Marquardt algorithm is adopted during the fitting process using this function. This algorithm is a commonly used nonlinear least squares optimization algorithm that combines the advantages of the gradient descent method and the Gauss-Newton method. It has good convergence and stability when dealing with nonlinear least squares problems. The specific principle can be found in [38].
# Resource Allocation in 5G Cellular IoT Systems with Early Transmissions at the Random Access Phase
## 5 Numerical Analysis
### Comparison of NB-IoT Transmission Schemes  
In this section, we provide a direct comparison of NB-IoT transmission schemes in terms of delay. To this end, Figure 14 shows the mean delay for uplink packets for optimal resource allocations between the RA and DT phases. Confirming the expected predictions, the gain relative to the transmission delay increases when more users transmit small amounts of data. Specifically, for \(p_{s}^{(E)}=0.2\), the delay gain is already almost 3 ms, while for \(p_{s}^{(E)}=0.4\), it raises further to 6 ms, which results in an approximately 20-40% delay reduction.  
By cross comparing the results presented for conventional access and for EDT schemes, we can also observe that, for the load point that optimally divides the resources between the RA and DT phases, the EDT gain in latency is rather consistent and is around 20-40% correctly observed. This is mainly because EDT allows one to skip DT phase, leaving only the RA phase loaded.
## 1 Introduction
The hybrid HVDC breaker has been proposed and investigated in References [29; 30; 31] to eliminate on-state power loss and limit fault current within several milliseconds. Parametric analysis of hybrid DCCB has also been conducted thoroughly considering the influence of the main parameters on the system and the breaker design [32]. Moreover, an interlink DCCB has been proposed to maintain the fault current interruption ability with a few components to reduce the overall cost of the DCCB in the DC grid [33]. In Reference [24], varying the DC current is considered an underdamping decay process, given the small resistance in the fault circuit. Thus, the fault current-limiting inductance \(L_{FCL}\) cannot change the damping characteristics which refer to criterion \(R<2\sqrt{L/C}\). That is, \(L_{FCL}\) can only limit DC fault current, but not relieve the overcurrent effect in the converter and AC sides [24]. The SFCL has not been applied extensively in real projects because of its high cost and lack of maturity, particularly with respect to SFCL recovery after being activated. The main advantage of the SFCL is that it does not influence the dynamic response under normal state. The direct installation of the DC reactor affects the system's normal operation and DCCB isolation speed [34]. Therefore, the present study proposes an enhanced fault current-limiting circuit (EFCLC) that primarily consists of energy dissipation resistance, limiting reactor, surge arrester, and semiconductor switches on the basis of existing works. The EFCLC aims to limit fault current through converter arms and DC line before the DCCB operates, thereby decreasing the peak current for fault interruption and reducing overcurrent effect on converter arms. Moreover, the required DCCB capability could be reduced, given limited fault current with EFCLC and more time is saved for fault detection, since fault current rising speed is more or less restricted. The remainder of this paper is organized as follows. Section 2 thoroughly analyzes DC fault current on the basis of theoretical calculation and simulation verification. Section 3 presents the topology and working principle of EFCLC. Section 4 performs the parametric design study of EFCLC. Section 5 further investigates the proposed scheme with EFCLC in terms of FCL ability and cost. Finally, Section 6 summarizes the conclusion and future scope.
## 3 Proposed Method
### Reconstruction Module  
Once the cross-modality fusion features of the image are obtained, they are passed to the reconstruction module as depicted in Figure 7. The size of the input image is \(H\times W\times C\). Following several convolution operations and a pixel shuffle, the pansharpened image is generated at this stage, resulting in a size of \(4H\times 4W\times 4\).  
This module includes several convolutional layers (\(conv3\times 3\)) and a PixelShuffle operation. Convolutional layers inherently contain learnable parameters (weights and biases), which are optimized during training using backpropagation. In the network architecture, following the second pixel-shuffle operation, the size of the feature transforms into \(4H\times 4W\times C\). At this stage, the feature is first directed into the initial \(conv3\times 3\) layer. The primary function of this \(conv3\times 3\) layer is to extract feature maps across C channels. Subsequently, the final \(conv3\times 3\) layer is responsible for generating the ultimate 4-channel fused outcome.  
Figure 6: Cross-Attention Block (CAB).  
Figure 7: Reconstruction module.  
Notably, in Figure 7, two consecutive \"3 \(\times\) 3 Conv\" blocks are presented at the end. This design is the result of a comprehensive experimental exploration and meticulous design considerations. These two consecutive convolutional blocks play a crucial role in further feature extraction. They can remarkably enhance the network's capacity to capture detailed features within the input data, thereby effectively improving the overall performance of the network.  
Since the convolutional layers contain learnable parameters, the reconstruction module will be updated during training alongside other components of the network. The ReLU activations, which are nonlinear transformations, further ensure the module participates in the training process by introducing nonlinearity.  
The PixelShuffle operation itself is a deterministic function used for upsampling, which does not introduce any learnable parameters. However, it works with the convolutional layers that do have learnable parameters, thus participating in the end-to-end optimization of the network.  
PixelShuffle is a prevalent image processing technique in deep learning. This technique effectively enhances image resolution by rearranging pixels [23]. Its main role is to convert low-resolution feature maps into high-resolution outputs through pixel rearrangement. This operation is often referred to as spatial rearrangement or pixel arrangement. The advantage of PixelShuffle technology is that it can learn complex image features through deep learning models, enabling the generation of more realistic and detailed high-resolution images. Additionally, since PixelShuffle does not require extra upsampling parameters, such as convolution kernels used in transposed convolution, it enhances the quality of the generated images without increasing the model's complexity.
## 14 Focus on Water Supply
For instance, areas suitable for Managed Aquifer Recharge (MAR) were identified near the South Africa/ Botswana border using SAW with nine criteria (land slope, land-use, soil, rainfall, proximity to water bodies, drainage density, depth to groundwater, lineament density, lithology), [155]. That study recognized that there were correlations between the criteria and took account of this in assigning weights. Various options for pumping and storing groundwater were investigated by [156] using 5 main groups of criteria (economic (divided into five sub categories), energy, environmental, water loss, and social) [156]. A combination of methods, AHP (for weights) and TOPSIS for the ranking, was applied to a case study in Spain, that showed how the optimal energy source changed depending on the depth and extent of the aquifer. In an EU project related to water supply in India, a software tool was developed to determine the best water treatment process. It was called the \"WETSUIT\" package [157] and used 30 objectives grouped under four headings (economic, socio-economic, technical and environmental) and the AHP method. Key papers on applications are listed in Table 13.  
The eight special focus analyses above show that  
* There is a very substantial difference in the articles returned from a bibliometric search using broad keywords compared to using focused keywords. This is despite the expectation that the broader keywords should cover the topics of the focused search. This is a concern for at least two reasons. (a) Many useful publications can be missed if the search terms are too broad, even when a large number of publications are returned by the broad search. Additionally, (b) even when the engineer doing the search realizes that focused keywords are more useful, there is an added responsibility to make sure the focused terms cover all of the domains required in the search. * The decision criteria keywords most frequently used in the broad search relate to sustainability, environment, risk, and safety, but cost does not feature in the list nor does physical resource usage. * The results of the individual focused searches had only marginal overlap with the earlier broad civil engineering searche. However, some returned a relatively large number of articles covering many aspects of the specific topic, especially the \"route selection\", \"sewage treatment\" and \"water supply\" searches. * While many MCDA methods are mentioned, AHP is by far the most used method, followed by TOPSIS and SAW. Many papers using AHP justify their choice because it is the most frequently used method. This is not a sufficiently rigorous position and more emphasis is needed on choosing the most appropriate MCDA method to suit the specific problem and the information available. The non-compensatory methods are not as frequently mentioned, but of these, PROMETHEE is the most prominent. * In some cases, combinations of methods are used. For instance, AHP for determining weights has been used with TOPSIS for the decision methodology. PROMETHEE has