esa-sceva/satcom-chunk-collection huggingface dataset:
## 4 Discussion
### Temporal Analysis of Illumination Conditions  
Temporal analysis for the whole Landsat reflectance collection in the area showed significant and increasing trends for IC, EVI, and NDVI. We employed information on zenith and azimuth solar angles already present in each available image, eliminating the need for merging information between Landsat and MODIS sensors to model or simulate data. Intra- and inter-annual variations of VI as a response to changes in sun-sensor geometry and variations in sun-sensor geometry itself have been conducted using MODIS and Landsat collections, but covering shorter periods of time [18; 19; 21]. Some of the observed changes in IC agree with observations reported after analyzing the orbit change in Landsat 5 between the years 1995-2000, but here we describe the IC variations better at the terrain level, something that was not possible to reflect in that study [18]. Although the terrain is believed to remain constant, the use of the SRTM dataset to model IC throughout the whole period could be a source of bias in some areas.
## 5 Diagnostic Methods and Techniques
### Invasive Imaging Modalities  
#### 5.1.1 Transesophageal Echocardiography  
TEE utilizes high-frequency sound waves to capture cardiac images via the esophagus and is widely used to detect thrombi and measure hemodynamic parameters (see Figure 2A,B). It is considered cost-effective and efficient for obtaining images, making it the \"gold standard\" for detecting LAA thrombi [89; 90]. Studies have shown that TEE has a sensitivity and specificity approaching 100% for assessing LA thrombi [89]. Color Flow Doppler imaging aids in evaluating the LAA and identifying thrombi, while Tissue Doppler imaging assesses the myocardial function of the LAA region, providing additional information for thrombus risk stratification [91]. TEE's high temporal resolution allows for continuous hemodynamic parameter curves throughout the cardiac cycle [92]. It also guides and evaluates LAA occlusion procedures by providing real-time imaging without the need for contrast agents or ionizing radiation [93], further establishing it as the \"gold standard\" for peri-procedural imaging during LAA occlusion procedures [94].  
However, as an invasive procedure (see Figure 2C), TEE carries potential, albeit rare, life-threatening complications [98; 99]. Traditional TEE may also struggle to accurately measure the hemodynamic parameters in thrombus regions due to its limitations in differentiating between muscle and thrombus, as well as in detecting thrombi obscured by anatomical protrusions [99]. To enhance the imaging quality of TEE, several strategies have been proposed. For instance, ultrasound contrast agents can serve as effective ultrasound reflectors, increasing blood echogenicity and minimizing imaging artifacts [100]. Additionally, a computer-aided diagnostic algorithm utilizing artificial neural networks has been developed to enhance the accuracy of TEE in diagnosing LA/LAA thrombi in patients with AF [101].
# Optical Injection Locking for Generation of Tunable Low-Noise Millimeter Wave and THz Signals
Integration of such transmitters on the chip is an important step towards the practical use of devices and systems due to the significant reduction in costs and power consumption and the improvement in scalability. In this regard, research on the integrated component is of considerable interest. In this work, we measure and discuss in detail the separate effects: phase noise, fine- and coarse-tuning, and the locking range for sub-THz and THz generation. Synchronization of two monotonically integrated semiconductor lasers by means of injection locking (IL) of an optical frequency comb was demonstrated. Linewidth narrowing and frequency stabilization of the lasers were observed. Active filtering with a set of two slave lasers was demonstrated for different sets of optical lines in OFC. This method enables selection of the lines in an OFC with different frequency spacing between them and subsequently use them for generation of the sub-THz and THz signals. Phase noise performance of a single and a pair of lasers were measured. Phase noise was further analyzed for different injection ratios and different master tone offsets. Coarse- and fine-tuning mechanisms during IL were studied and discussed in detail. By providing a detailed study of injection locking and phase noise performance, this work proves the feasibility and flexibility of high-purity sub-THz and THz signals generation based on on-chip integrated lasers locked onto an optical frequency comb. The remainder of this manuscript is structured as follows: Section 2 describes OIL and its application for generation of sub-THz and THz signals; Section 3 give an overview of the experimental setup; Section 4 demonstrates the experimental results; and Section 5 underlines the outcome of this work.
## 3 Results and Discussion  
### Leading Process  
#### 3.1.1 Effect of H\({}_{2}\)SO\({}_{4}\)Dosage  
The effect of H\({}_{2}\)SO\({}_{4}\) concentration on leaching efficiency of vanadium and chromium was investigated while keeping the reaction time at 180 min, reaction temperature of 90 \({}^{\circ}\)C, and liquid-to-solid ratio of 5:1 mL/g. The concentration of H\({}_{2}\)SO\({}_{4}\) was set as 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, and 30 wt.%. The results are detailed in Figure 3.  
The vanadium and chromium were existed in low valence according to the results shown in Figure 1. The chromium was easy to leach out and the leaching efficiency of chromium was increased along the concentration of H\({}_{2}\)SO\({}_{4}\). The leaching efficiency was 92.10% at 5 wt.% H\({}_{2}\)SO\({}_{4}\) and up to 99.80% at 30 wt.% H\({}_{2}\)SO\({}_{4}\).  
Figure 3 indicates that the low-valence vanadium was hard to leach out. Only 10.24% of vanadium was leached out at 5 wt.% H\({}_{2}\)SO\({}_{4}\). Even when the concentration increased to 30 wt.%, the leaching efficiency of vanadium only reached 57.8%, nearly half of the vanadium was retained in the residue. The vanadium in low valence was hard to leach out [5], in order to improve the leaching of vanadium, some enhanced technology was needed [9,25].
## 4 Conclusions  
In summary, we have demonstrated that, by mirror-inducing the magnetic anapole state (MAS) and asymmetrically optimizing its silicon nanostrip in the proposed metal-dielectric hybrid metasurface, the average enhancement factor (EF) of the electric field can be greatly enhanced, as well as optical bistability performance. The results indicate that, with appropriate asymmetric geometries, a significant enhancement of the relevant property (EF in this case) is achieved. Moreover, the optical bistability of the proposed metasurface is investigated, achieving the thresholds of \(I_{\text{ON-OFF}}\) and \(I_{\text{OFF-ON}}\) of 8.5 MW/cm\({}^{2}\) and 7.1 MW/cm\({}^{2}\), respectively, which are the lowest thresholds when compared to the previous works based on silicon nanostructures. Together with the ON/OFF ratios of \(>\)5.6 and the insensitive dependence on the incident angle of \(<\)10\({}^{\circ}\), the proposed metasurface paves the way for applying miniaturized bistability to all-optical switches and modulators, logic and memory devices, and on-chip optical communications.  
\begin{table}
\begin{tabular}{l c c c c} \hline
**Structure** & **Type of Resonance** & **The \(\chi^{(3)}\) of Si (m\({}^{2}\)/V\({}^{2}\))** & \(I_{\text{ON-OFF}}\) (MW/cm\({}^{2}\))** & \(I_{\text{OFF-ON}}\) \\ \hline Ring [26] & Fabry-Perot resonance & \(6\times 10^{-18}\) & \(7.5\times 10^{3}\) & \(6\times 10^{3}\) \\ Grating [27] & Guided-mode resonance & \(6\times 10^{-18}\) & 350 & 200 \\ Photonic Crystal [28] & BIC resonance & \(2.84348\times 10^{-19}\) & 150 & 75 \\ This work (Symmetry) & MAS resonance & \(2.84348\times 10^{-19}\) & 25.0 & 19.6 \\ This work (Asymmetry) & MAS resonance & \(2.84348\times 10^{-19}\) & 8.5 & 7.1 \\ \hline \end{tabular}
\end{table}
Table 1: Comparison of optical bistability thresholds from nanostructures. The Kerr material is silicon.  
Figure 7: Dependences of switch thresholds on the incident angle.  
**Author Contributions:** Conceptualization, R.X. and G.C.; methodology, R.X. and G.C.; software, R.X., S.T., Y.W. and G.C.; validation, R.X., S.T., Y.W. and G.C.; formal analysis, R.X. and G.C.; investigation, R.X., S.T., Y.W. and G.C.; resources, R.X. and G.C.; data curation, R.X. and G.C.; writing--original draft preparation, R.X., S.T. and G.C.; writing--review and editing, R.X., S.T. and G.C.; visualization, R.X. and G.C.; supervision, R.X., S.T., Y.W. and G.C.; project administration, R.X. and G.C.; funding acquisition, G.C. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the National Natural Science Foundation of China under Grant 92163134 and 62271429.  
Not applicable.  
**Data Availability Statement:** The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors declare no conflicts of interest.
## 1 Introduction
### Paper Contribution  
As the three-dimensional (3D) beamforming is necessary for many applications which utilizes planar arrays, therefore in this paper, an efficient beamforming technique is proposed to generate beam patterns with controlled SLL values. The proposed technique utilizes the unique patterns of sidelobes in the uniform feeding case to generate secondary mainlobes with the same levels of the sidelobes which are then weighted properly and subtracted from the original pattern and the process can be repeated to achieve the required SLL. The proposed MPS beamformer analyzes the sidelobes in each reduction cycle to find the proper corresponding weights to achieve the convergence. The algorithm is extensively investigated where its performance is analyzed at different array sizes and configurations, number of sidelobes adopted in the reduction process, convergence controlling and limitations, and scanning of the mainlobe and its effect on the SLL variation. The simulation results show that the proposed MPS beamformer can achieve deep SLL near \(-65\) dB or less according to the number of number of iterations and can be applied to any planar array structure with different dimensions including rounded corners rectangular arrays. In addition, the proposed MPS beamformer has convergence speed that is more than five times compared with that of the SSD algorithm which is essential for real time beamforming using massive planar arrays. In addition, the array optimization can be achieved only one time to find the required weights at the broadside direction of the array, then can be rephased to generate scanning beams of the same SLL without re-optimization. This important feature greatly reduces the processing time until different SLL values are required.
# Low-Power Wireless Data Transfer System for Stimulation in an Intracritical Visual Prosthesis
## 4 Experimental Demonstrator
### External Transmitter  
For the experimental demonstrator setup, the external transmitter, which is a BPSK transmitter, is emulated using two single pole single throw switches (SPST). Figure 5 shows the circuit schematic of the external transmitter demonstrator. To achieve BPSK functionality, the inputs into the second switch, which are the carrier signal and data bits, are inverted. The outputs of both switches are connected. Together, the switches act as a switch pair to form the BPSK modulated signals. The DC component is filtered using a high-pass filter. The two SPST switches are in a single component: the DG411 LE from Vishay Siliconix Pennsylvania, USA. The inverters are SN74F04 from Texas Instruments, Texas, USA. By-pass capacitors of 0.1 uF were used to isolate the power supply of each sub-IC.
## 4 Conclusions  
In this work an overview of near-infrared Si PDs based on IPE occurring in graphene, has been presented. Firstly, we have described how IPE theory needs to be properly modified in junctions involving two-dimensional material, showing as this effect is intrinsically enhanced with respect to  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Ref.** & **Responsivity** & **Dark Current** & **Bandwidth** & **SBH (eV)** & **Type** & **Conf.** \\ \hline
[27] & 9.9 mA/W & \(\sim\)2.4 \(\upmu\)A & & & & \\ at 1550 nm and \(-\)16 V & at \(-\)16 V & - & 0.44–0.46 & Exfol & Free-space \\ \hline
[36] & 370 mA/W & \(\sim\)3 \(\upmu\)A & & & & \\ at 1550 nm and \(-\)3 V & at \(-\)3 V & - & 0.34 & CVD & Waveguide \\ \hline
[38] & 20 mA/W & \(\sim\)147 at \(\upmu\)A & 120 MHz & & & \\ at 1550 nm and \(-\)10 V & at \(-\)10 V & (Estimated) & & & \\ \hline
[39]* & 0.43 A/W & 561 nA if & & & & \\ at 1550 nm and 0 V & graphene radius & & & & \\  & (gr) \(<\)15 \(\upmu\)m & & & & \\ \hline
[28] & 0.16 mA/W & \(\sim\)3 \(\upmu\)A & KHz regime & & & \\ at 2000 nm and 0 V & at \(-\)6 V & (Estimated) & & & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of selected near-infrared silicon Schottky photodetectors based on graphene.  
Figure 8: (a) Schematic cross-sectional view of the graphene/Si Schottky PD investigated in Casalino [28], (b) Measured current vs incident optical radiation. Reprinted with permission from ([PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON]. Free-Space Schottky Graphene/Silicon Photodetectors operating at 2 \(\upmu\)m. _ACS Photonics_**2018**, \(5\), 457–4585. Copyright (2018) American Chemical Society.  
classical device based on 3D materials (metals). Then we have described and discussed in detail the most common configurations reported in recent literature including both vertically-illuminated and waveguide structures. Finally, a quantitative comparison of selected device has been given and summarized in Table 1.  
In some cases, this new family of devices shows performance that is already comparable to PDs based on Ge technology utilized in Si photonics for both telecom and datacom applications. In addition, these devices show the potentialities for working at longer wavelengths opening perspectives for new applications including optical communications, light-radars and biomedical imaging. However, the possibility to integrate 2D materials like graphene in Si technology for high-volume production remains a crucial point that needs to be properly addressed in the next future.  
This research has received funding from the ATTRACT project funded by the EC under Crant Agreement 777222.  
The author declares no conflict of interest.
## 12 Evolving Fuzzy Techniques for EEG Artifact Removal
### Fuzzy Approaches for the Removal of Artifacts: Case Studies  
In the context of contemporary research on neurology and EEG signal analysis, a limited number of publications have been selected to outline four essential guidelines on the emerging field of EEG artifact removal using fuzzy TS systems. This focused selection highlights the effectiveness of fuzzy logic-based techniques, integrated with neural networks, in significantly improving the quality of EEG signals. Through these exemplary studies, it is observed how fuzzy approaches not only contribute to the removal of internal and external artifacts but also provide a substantial increase in diagnostic result accuracy, underscoring their importance in the early and accurate diagnosis of neurological disorders. This synthesis of selected research provides a clear picture of the potential and future directions of scientific research in EEG artifact removal using fuzzy TS techniques. The first method [145] mentioned utilizes the TS fuzzy system to address internal artifacts in Alzheimer's patients, demonstrating how phase synchronization analysis can isolate intrinsic anomalies associated with pathological conditions in the EEG signal. This approach improves model interpretation and enhances classification accuracy, highlighting the importance of precisely modeling EEG signal characteristics in Alzheimer's diagnosis. The second study [146] extends the application of fuzzy techniques to the analysis of EEG networks through the Weighted Visibility Graph, providing a distinctive framework of the structural differences in EEG signals between healthy subjects and those afflicted with Alzheimer's. This approach marks a significant advancement in recognizing the specific network topologies characteristic of neurological disorders, showing how the integration of network-based and fuzzy learning techniques can significantly enhance the effectiveness of EEG signal classification. The third and fourth methods [147,148], utilizing ANFIS (Adaptive Neuro-Fuzzy Inference System) for EEG signal classification in detecting epileptic seizures and in brain
## 6 Experiment and Result Analysis
### Analysis of Model Complexity  
To validate the practical applicability of the proposed FG-TEFusionNet model, we conducted a comprehensive complexity evaluation from both time and space complexity perspectives. For temporal complexity optimization, the lightweight SENet module simplifies the overall network architecture by streamlining computation processes, effectively reducing floating-point operations (FLOPs) and accelerating training convergence. In terms of spatial complexity, the integration of global average pooling significantly decreases the number of model parameters, thereby lowering structural complexity while enhancing generalization capability. Notably, our framework achieves high detection performance with reduced overall complexity, accompanied by additional measurements of single-frame inference time. Table 14 summarizes the complexity comparison and single-frame inference time between the model proposed in this paper, XceptionNet, and EfficientNet.  
Aiming at the trade-off problem between model efficiency and performance in the task of deepfake detection, this study conducted a comprehensive comparison between FG-TEFusionNet and mainstream baseline models (XceptionNet, EfficientNet-B4) (Table 14). Although the number of parameters of our model (18.6M) is similar to that of EfficientNet-B4 (19.3M), through the collaborative optimization of channel attention (SE Module) and global average pooling, while the FLOPs only increased by 4.3%, the inference speed was improved by 26.2% (28.7 ms/frame vs. 38.9 ms/frame). In terms of performance, FG-TEFusionNet achieved an AUC of 99.83% on FaceForensics++ (Table 14), which was 1.1 percentage points higher than that of EfficientNet-B4 (98.74%) and 0.87% higher than that of XceptionNet (98.97%). These results indicate that a moderate targeted investment of computational resources (such as SENet) can significantly enhance the discriminative ability for forged features. Moreover, through the optimization of attention and global average pooling, the additional complexity cost can be offset, and the requirements of real-time detection can be met, providing a feasible solution for practical application scenarios with limited resources.
## 4 Discussion
In such cases, the differences between the positions of the points from the original cloud and the mesh created from the diluted point cloud prevail and RMSD can provide a relatively good evaluation of the dilution accuracy. As well as its good performance in reducing the point clouds and preserving details, the proposed progressive dilution algorithm comes with the additional benefits of simplicity (and, thus, rapidity of calculation) and availability (i.e., it can be easily implemented using the free CloudCompare software. For this reason, we believe that it has great potential to be used for the creation and sharing of digital twins of historical buildings. As progressive dilution would likely perform even better on modern constructions without embellishments, the algorithm is likely to be suitable not only for historical buildings but also for any other constructions and even contemporary civil engineering or for the creation of digital twins of entire cityscapes. It is, however, necessary to draw attention to the basic prerequisite for the proper functioning of the algorithm--well-prepared data. The algorithm is based on the detection of data scattering from the fitted plane. For this reason, input data must be well cleaned of outliers arising due to errors in data registration, errors caused by a suboptimal combination of several scans (i.e., when the overlay of two scans creates two parallel surfaces) or suboptimal processing of the photogrammetric method producing noisy clouds. Such noise/parallel surfaces would inherently lead to an incorrect assessment of flatness (i.e., such areas would be considered areas of high detail) and progressive dilution would fail. Therefore, operator supervision and evaluation of the input cloud are required. This is, however, a common problem for all dilution algorithms--once any algorithm is fed with poor data, the result is bound to be poor as well.
## 3 RS Applications in Ocean
### Ocean Tide (OT)
#### 3.5.4 Altimeter  
Satellite altimetry data have been utilized to study OT and improve the global OT models [296; 297]. Furthermore, utilizing altimetry technology is one of the approaches used to detect shoreline changes over tidal flats [298]. For two decades, global SL changes were extensively studied using satellite altimetry [299]. For instance, [PERSON] et al. [49] estimated water level over tidal flats by analysis of the waveforms. [PERSON] et al. [299] also discussed the sufficiency of the coastal Digital Elevation Model (DEM) compared to current altimetry methods. The measurement of quantitative changes of tidal flats was performed by comparing the DEM produced using the waterline technique applied to SAR images and a DEM constructed from airborne altimetry data acquired in different years [300]. As discussed, satellite altimetry also enables global mapping of significant OWH, the results of which can be used for OT studies. For example, [PERSON] et al. [301] proposed a new algorithm for reprocessing altimetric waveforms to estimate significant OWH over a challenging tidal flat using Envisat, Jason-1, and Jason-2 data.  
Satellite altimetry is highly effective in observing global tidal currents. The satellite altimetry sampling illustrates a broad view of the global distribution, variability, and spatial structures of currents. Considering the potential of tidal current energy at straits, [PERSON] et al. [302] proposed a method to provide a global map of significant OWH. [PERSON] et al. [303] also used TOPEX/Poseidon altimeter data as one of the inputs to model tidal currents. Additionally, [PERSON] and [PERSON] [304] argued that the current magnitude is underestimated in altimetry-constrained OT databases.
# Mobile User Connectivity in Relay-Assisted Visible Light Communications
###### Abstract  
In this paper, we investigate relay-assisted visible light communications (VLC) where a mobile user acts as a relay and forwards data from a transmitter to the end mobile user. We analyse the utilization of the amplify-and-forward (AF) and decode-and-forward (DF) relaying schemes. The focus of the paper is on analysis of the behavior of the mobile user acting as a relay while considering a realistic locations of the receivers and transmitters on a standard mobile phone, more specifically with two photodetectors on both sides of a mobile phone and a transmitting LED array located upright. We also investigate dependency of the bit error rate (BER) performance on the azimuth and elevation angles of the mobile relay device within a typical office environment. We provide a new analytical description of BER for AF and DF-based relays in VLC. In addition we compare AF and DF-based systems and show that DF offers a marginal improvement in the coverage area with a BER \(<10^{-3}\) and a data rate of 100 Mb/s. Numerical results also illustrate that relay-based systems offer a significant improvement in terms of the coverage compared to direct non-line of sight VLC links.  
Keywords:amplify-and-forward relaying; cooperative communication; decode-and-forward relaying; visible light communications +
Footnote †: journal: Sensors