esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Results and Discussion
### Comparison of Energy Demand and Implications  
In traditional EC systems for phosphorous removal using aluminum electrodes or a combination of aluminum and iron electrodes, the energy demand per cubic meter  
\begin{table}
\begin{tabular}{c c c c c c} \hline Initial pH & 5.0 & 6.0 & 7.0 & 8.0 & 9.0 \\ \hline Final pH & 5.6 & 6.4 & 7.3 & 7.9 & 8.8 \\ \hline \end{tabular}
\end{table}
Table 1: The pH value changes of the aluminum–air fuel cell before and after operation for 60 min.  
Figure 6: The relationship between the initial phosphate concentration and phosphate removal in the aluminum–air fuel cell.  
of P-wastewater was approximately 1.1-6.1 kWh, as shown in Table 2. When an air cathode was applied as the electrode, the energy consumption decreased compared with the traditional EC system. In the air cathode EC system which used a titanium inert electrode, only 0.009-0.06 kwh was added, and the operation time required was only 15 min [13]. Photovoltaic solar modules were also applied to power the EC process, and the energy from the solar energy modules was enough for the EC system, although the solar energy conversion efficiency was less than 13% [30]. For the aluminum-air fuel cell, with a 10 mmol/L NaCl electrolyte and a 10 \(\Omega\) operation condition, the average power density at 60 min was approximately 160 mW/m\({}^{2}\). As the power density curves show, the aluminum-air fuel cell output power density was related to the output current. The power production was less than that of the solar cell; however, the aluminum-air fuel cell electrocoagulation system did not require an external electricity unit such as a solar cell module. This simple device is more practical in wastewater treatment, and solar energy is also highly dependent on weather. Compared with the traditional EC system, the operating cost for anode consumption is similar, but the cost of the air cathode in the aluminum-air fuel cell is higher than that of the conventional EC cathode [19]. The air cathode cost and lifetime should be one of the future research points considered for scale-up. Therefore, in future studies, the construction of a scale-up system, the electrode lifetime, and overall economic assessment including labor, sludge handling, maintenance, and depreciation costs will be key issues for practical application [18; 36; 37; 38].  
Another advantage of the metal-air fuel cell is that the air cathode is capable of generating hydrogen peroxide with a suitable oxygen reduction catalyst, which has the potential to treat wastewater by combining coagulation and oxidization processes. For domestic wastewater treatment, the aluminum-air fuel cell can be used at the pre-treatment segment and the advanced treatment segment to remove phosphate. Organic contaminants such as antibiotics, resistant genes, and persistent organic pollutants which are harmful to human health can coexist with phosphate in wastewater. The multiple physicochemical processes in aluminum-air fuel cells provide promising methods to treat the complex effluents in the advanced treatment stage.
# FPGA Applied to Latency Reduction for the Tactile Internet
## 8 Conclusions  
This paper presented an FPGA hardware reference model for four modules implementing robotics-associated algorithms. The FK-HMD and FK-HSD modules implement the forward kinematics, the IK-HSD module implements the inverse kinematics, the KFF-HMD module implements the kinesthetic feedback force, and the FBF-HSM module implements the feedback force. The parallel FPGA implementation of the four modules is intended to increase the tactile system's processing speed to meet the latency constraints required for tactile internet applications. The modules were designed using a full-parallel implementation which works on a hybrid scheme that uses fixed point and floating point representation in distinct parts of the architecture. Compared to the state-of-the-art, this work describes and implements four different robotics algorithms in FPGA. The implementations presented in this work achieve higher module processing speed when compared to equivalent implementations from the state-of-the-art. All the modules presented here were analyzed based on the synthesis results, which included the FPGA resource utilization, sampling rate, and yield. Based on the synthesis results, it was observed that the implementations achieved high module processing speed, far below the latency limit of 1 ms. Hardware modules accelerated 93\(\times\) compared to the 37.5 us time constraint. This work demonstrates that using embedded systems on devices such as FPGAs enables parallel algorithm implementation, thus speeding up data processing and minimizing execution time. Runtime gains can make processing time possible for critical applications that require short time constraints or a large amount of data to be processed in a short time frame.  
All the authors have contributed in various degrees to ensure the quality of this work (e.g., [PERSON], [PERSON], [PERSON] and [PERSON] conceived the idea and experiments; [PERSON], [PERSON], [PERSON] and [PERSON] designed and performed the experiments; [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] analyzed the data; [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] wrote the paper. [PERSON], [PERSON] and [PERSON] coordinated the project). All authors have read and agreed to the published version of the manuscript.  
**Funding:** This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)--Finance Code 001.  
**Acknowledgments:** The authors wish to acknowledge the financial support of the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) for their financial support.  
**Conflicts of Interest:** The authors declare no conflict of interest.
# Assessing the Potential of PlanetScope Imagery for Iron Oxide Detection in Antimony Exploration
## 4 Results
### Region of Interest  
Clusters in hot colors are iron oxide pixels; the behavior of the clusters of interest is pixels with high to very high values surrounded by clusters with medium-high values (see Figures 5 and 6).  
It was possible to identify four ROIs (Figure 5) in the test 1 results (fuzzy of all satellite images). The ROI 1 is located 1.2 km (kilometers) northwest of Frexas village, ROI 2 is located 600 m (meters) southwest of Vila Verde village, ROI 3 is located 1.8 km northeast of Vila Verde village, and ROI 4 is located 3.1 km east of Freixeda village.  
Figure 6 shows the result of test 2 (fuzzy without PS image). Six ROIs were identified, and four of them (ROIs 1, 2, 3, and 4) are the same identified in test 1. ROI 5 is located 3.7 km southeast of Vila Verde city and ROI 6 is located 3.1 km east of Freixeda village. The location of the ROIs in the study area can be observed in Figure A2 (Appendix A). Table 3 shows the percentage each class occupies for Test 1 and Test 2 results.  
Figure 3: Absorption features and reflectance peaks of Goethite and Hematite spectra.  
Figure 4: Spatial distribution of pixels classified between classes 12 and 16, derived from band ratio (BR) analyses using PS, Sentinel-2, ASTER, and Landsat 9 imagery. These classes represent increasing probabilities of Fe\({}^{3+}\) presence, with warmer colors indicating higher values. Subfigures illustrate the BR results and their corresponding color slice visualizations for each satellite: (**a–c**) BR map, color slice of BR, and NDVI for PS; (**d–f**) BR map, color slice of BR, and NDVI for Sentinel 2; (**g–i**) BR map, color slice of BR, and NDVI for ASTER; (**j–l**); BR map, color slice of BR, and NDVI for Landsat 9.  
Figure 5: Regions of interest (ROIs) identified in Test 1 (using PS data). Subfigure (**a**) corresponds to ROI 1, located approximately 1.2 km northwest of Frexas village; (**b**) shows ROI 2, situated about 600 m southwest of Vila Verde village; (**c**) presents ROI 3, located 1.8 km northeast of Vila Verde village; and (**d**) displays ROI 4, positioned roughly 3.1 km east of Freixeda village.  
Figure 6: ROI test 2. Regions of interest (ROIs) identified in Test 2 (without PS data). (**a–d**) corresponds to ROIs 1 to 4, which are the same regions previously identified in Test 1; (**e**) presents ROI 5, located approximately 3.7 km southeast of Vila Verde city; and (**f**) displays ROI 6, positioned about 3.1 km east of Freixeda village.
# Testbed for Experimental Characterization of Indoor Visible Light Communication Channels
## 6 Conclusions  
We have designed and manufactured a testbed for the experimental evaluation of indoor VLC schemes. In the developed mockup, the receiver position and orientation can be dynamically established with high precision for a static configuration of walls and arrangement of LED lamps on the ceiling. Adaptive rate OFDM with timing synchronization and channel equalization is implemented to evaluate the system performance as a function of the position and orientation of the optical receiver. Several simulation studies have been conducted so as to demonstrate the suitability of this small-scale prototype to be representative of real VLC scenarios. Preliminary experiments have been focused on studying single-user MISO systems, where a good agreement with simulation results has been observed. The positive influence of the contribution of reflected light in the measured throughput has been assessed, proving that this contribution should not be neglected as it is usual in many theoretical VLC studies, where only the LOS contribution is considered. Certain performance enhancement has also been observed when the optical detector is properly oriented trying to maximize received power from its serving lamps. However, vertical orientation upward still presents a good trade-off between ease of implementation and achievable data rates with lower practical performance deterioration than predicted  
Figure 17: Summary of throughput maps for different configurations (if not specified, the receiver points vertically upward): (**a**) One-lamp transmission. (**b**) Four-lamp transmission without walls. (**c**) Four-lamp transmission with walls. (**d**) Four-lamp transmission with walls and receiver oriented as defined by Equation (14).  
by simulations. These behavior differences between experimental and simulated results confirm the difficulty of adequately modeling every practical issue, which makes us conclude the need for this kind of testbed for a more realistic characterization of indoor VLC scenarios, providing additional information to the theoretical studies. Future work will be aimed at evaluating multi-user MIMO VLC systems with imaging and non imaging angular diversity reception, applying space-division multiple access (SDMA) or non-orthogonal multiple access (NOMA) [35].  
Conceptualization, O.G.; methodology, M.F. and O.G.; software, M.F. and O.G.; validation, M.F. and O.G.; formal analysis, O.G.; investigation, M.F. and O.G.; resources, M.F. and O.G.; data curation, M.F.; writing--original draft preparation, M.F. and O.G.; writing--review and editing, O.G.; visualization, M.F. and O.G.; supervision, O.G.; project administration, O.G.; funding acquisition, O.G. All authors have read and agreed to the published version of the manuscript. This research has been funded by Spanish Government (Ministerio de Ciencia, Innovacion y Universidades) and the European Regional Development Fund (ERDF/FEDER) program under project TEC2017-84065-C3-2-R.  
The authors declare no conflict of interest.
###### Abstract  
Compared with the one immobilized in the conventional mesoporous microspheres, the enzyme immobilized in gigaporous microspheres showed much higher activity and better stability. To gain a deeper understanding, we herein selected lipase as a prototype to comparatively analyze the adsorption behavior of lipase at interfaces in gigaporous and mesoporous polystyrene microspheres at very low lipase concentration, and further compared with the adsorption on a completely flat surface (a chip). Owing to the limited space of narrow pores, lipase molecules were inclined to be adsorbed as a monolayer in mesoporous microspheres. During this process, the interaction between lipase molecules and the interface was stronger, which could result in the structural change of lipase molecular and compromised specific activity. In addition to monolayer adsorption, more multilayer adsorption of enzyme molecules also occurred in gigaporous microspheres. Besides the adsorption state, the pore curvature also affected the lipase adsorption. Due to the multilayer adsorption, the excellent mass transfer properties for the substrate and the product in the large pores, and the small pore curvature, lipase immobilized in gigaporous microspheres showed better behaviors.  
lipase; adsorption; gigaporous; mesoporous; microsphere; QCM-D Article
# Optically Transparent Honeycomb Mesh Antenna Integrated into OLED Light Source
## 2 Material Characteristic
### Substrate Characteristics  
The main characteristics of interest are optical transparency (Tsub), dielectric permittivity (\(\epsilon_{r}\)), and the tangent of the loss angle (\(tan(\delta)\)). The dielectric parameters were measured using the Vector Network Analyzer combined with the 85,070 B dielectric probe kit with a tolerance of \(\pm 5\,\%\) and \(\pm 0.05\,\%\) on the dielectric permittivity and dielectric losses, respectively. The measurement results of \(\epsilon_{r}\) and \(tan(\delta)\) are shown in Figure 1. According to this figure, the measured values at a frequency of \(5.16\,\mathrm{GHz}\) are \(\epsilon_{r}=6.2\) and \(tan(\delta)=0.05\).  
The other parameter studied is optical transparency in the visible spectrum. This parameter was measured using an optical bench at room temperature and a MINOLTA-CS-1000 spectroradiometer. First, the luminance of the OLED was measured. Secondly, the glass substrate was inserted through a lens holder in front of the objective, in order to intercept the entire luminance. Transparency is the ratio of the latter luminance to the first result at the corresponding wavelength. Figure 2 illustrates this optical transparency; the median value is around \(82.5\%\). Noise below \(480\,\mathrm{nm}\) results from low emission in this band, leading to an increased noise level.  
Figure 1: Dielectric permittivity and tangent of the loss angle.  
Figure 2: Optical transparency for glass substrate in the visible spectrum.
# Dynamic Induction Heating Temperature Field Analysis of Spiral Bevel Gears
## 3 Simulation Results and Discussion
### Effect of Current Intensity on Cear Shot-Peening Area and Surface Temperature Difference  
The temperature of the shot peening area and the coil heating area was extracted, the coil covered area was the heating area, and the opening area was the shot peening area, as shown in Figure 6. The research object was to determine the average temperature of the shot peening area (indicated by GSPA) and the average temperature difference between the shot peening area and the heating area (indicated by GSTD).  
\begin{table}
\begin{tabular}{c c c} \hline
**Parameters** & **Transverse Coil** & **Longitudinal Coil** \\ \hline Thermal radiation coefficient & 0.7 & 0.7 \\ Initial temperature/\({}^{\circ}\)C & 20 & 20 \\ Frequency/kHz & 10, 12.5, 15, 17.5, 20 & 10, 12.5, 15, 17.5, 20 \\ Current/A & 500, 750, 1000, 1250, 1500 & 500, 750, 1000, 1250, 1500 \\ Heating time/s & 90 & 90 \\ \hline \end{tabular}
\end{table}
Table 4: Simulation parameters.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline
**C** & **Si** & **Mn** & **P** & **S** & **Cr** & **Mo** \\ \hline
0.19–0.25 & 0.17–0.37 & 0.55–0.9 & \(\leq\)0.03 & \(\leq\)0.03 & 0.85–1.25 & 0.35–0.45 \\ \hline \end{tabular}
\end{table}
Table 3: Chemical composition of 20 CrMnTi (wt%).  
We calculated the temperature difference between the gear shot-peening area and the spiral bevel gear surface at different electric currents. The changes in the gear shot peening area (GSPA) temperature and gear surface temperature difference (GSTD) under different input electric currents of the two coil structures are shown in Figure 7. The effect of the electric current on the GSPA temperature is similar in pattern, and the two curves are approximately parallel. At the same electric current, the heating temperature of the TC was approximately 45 \({}^{\circ}\)C higher than that of the LC. As for the GSTD, when heated with a TC with a current of 1500 A, the maximum GSTD was 145 \({}^{\circ}\)C. The GSTD was approximately 75 \({}^{\circ}\)C when heated with an LC. This result indicates that when the gear is heated with a TC, the heat generated by the induced eddy currents is mainly concentrated on the gear surface, resulting in a greater temperature difference and a more pronounced temperature field on the tooth surface. Although the LC has a lower heating power because the coil is approximately parallel to the helical direction of the gear teeth, the tooth surface is heated more uniformly, resulting in a smaller temperature difference and more uniform temperature field on the tooth surface.
## 1 Introduction  
The Seebeck effect allows solid-state thermoelectric generators (TEG) to convert heat into electricity. They have several advantages over traditional generators, such as high efficiency, low maintenance, and the ability to operate in extreme environments. However, one of the challenges in using TEGs is maximizing the power delivered to the load. In a TEG system, the power output rests on the temperature gradient across the device and the thermal resistance. Non-uniform temperature distribution in the system can significantly affect the power output, leading to a decrease in the productivity of the system.  
Therefore, it is important to accurately track the maximum power point to optimize the TEG's performance.  
There have been several MPPT control techniques proposed in the literature to address this issue. One commonly used method is the perturb and observe (P&O) algorithm, which adjusts the operating point of the TEG in small increments and compares the power output to determine the maximum power point. However, the P&O algorithm can be slow and may not always converge to the optimal solution. Other methods, such as fuzzy logic and artificial-neural-network-based approaches, have been proposed to improve the convergence speed and accuracy of the MPPT process.  
Recently, metaheuristic algorithms have gained popularity for use in the MPPT control of TEG systems. Metaheuristic algorithms are optimization techniques that mimic the behavior of natural systems and can find near-optimal solutions to complex problems. They have the advantage of being able to handle the constraints and uncertainties present in real-world systems. Examples of metaheuristic algorithms that have been applied to TEG MPPT include particle swarm optimization (PSO), genetic algorithms (GA), and ant colony optimization (ACO).  
This work deals with complications generated by non-uniform temperature distribution across TEG module arrays connected in centralized control topology. The performance of the proposed algorithm is compared to other commonly used MPPT control techniques, including P&O, fuzzy logic, and artificial neural networks. The results show that the proposed algorithm can achieve faster convergence and higher efficiency compared to the other methods.  
Overall, the use of metaheuristic algorithms in the MPPT control of TEG systems has the potential to improve the efficiency and performance of these devices, causing them to be a viable alternative to traditional generators in a variety of applications.
# Underwater SLAM Meets Deep Learning: Challenges, Multi-Sensor Integration, and Future Directions
## 6 Practical Challenges in Underwater SLAM
### Underwater Communication
#### 6.1.2 Optical Communication  
Optical systems achieve high data rates (up to Gbps), making them attractive for SLAM applications that require streaming video to topside stations or other AUVs [87, 88]. However, optical systems are limited by water turbidity and require line-of-sight [89]. Vision-based SLAM performance varies with light penetration:  
* Clear water: Blue/green light (450-550 nm) penetrates up to 100 m, enabling monocular/stereo SLAM;
* Turbid water: Red light (600-700 nm) is absorbed quickly, necessitating active illumination or acoustic supplements [28].
# LoRaWAN Path Loss Measurements in an Urban Scenario Including Environmental Effects
## 4 Experimental Setup
### Network Deployment  
The ENs and the GW were deployed in the northern part of Medellin, where there is a valley with two mountains on each side, as shown in Figure 8. This topography allowed us to guarantee LoS conditions between each EN and the GW and avoid the obstruction in Fresnel zones, as shown in Figure 9 and as analyzed subsequently. The radius of the \(n^{th}\) Fresnel zone can be calculated by  
\[r_{n}=\sqrt{\frac{n\cdot\lambda\cdot d}{4}}, \tag{5}\]  
where \(r_{n}\) is the radius of the \(n^{th}\) Fresnel zone, \(n\) is the considered Fresnel zone, \(\lambda\) is the signal wavelength, and \(d\) is the distance between the transmitter and the receiver. To establish successful links, it is recommended that the first Fresnel zone (F1) is clear by more than 60% [12]. In our case, \(d\) is 2.11 km, 3.42 km, 5.32 km, and 8.21 km for EN1, EN2, EN3, and EN4 correspondingly, and \(\lambda=0.33\) m, so the F1 radii are 13.25 m, 16.87 m, 21.04 m, and 26.14 m. Because the worst F1 radii of our links are 3.9F1, 4.3F1, 3.2F1, and 2.2F1 (Figure 9), we are meeting and exceeding the minimum clearance of 60%, so our links can be modeled with LoS criteria. Thus, it can be concluded that the provided dataset is not dependent on the geometry of the terrain and can be used in other locations with similar weather characteristics.  
The coordinates of each device in the network and its corresponding antenna height (h) and altitude (Alt) are shown in Table 5.
# Performance Analysis of Post-Quantum Cryptography Algorithms for Digital Signature
## 4 Implementation
### Testbed  
The project's implementation was based on a WMWare virtual machine with Linux Debian installed. The advantage of this solution is the ease of management of the isolated environment and the ability to recreate the runtime environment. Virtual machines can be saved, cloned, and shared, allowing the exact setup to be reproduced on any compatible host machine. The detailed parameters of the used virtual machine are described in Table 2.  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Algorithm** & **Claimed** & **Public Key** & **Secret Key** & **Signature** \\  & **NIST Level** & **Size (Bytes)** & **Size (Bytes)** & **Size (Bytes)** \\ \hline Dilithium2 & 2 & 1312 & 2528 & 2420 \\ Dilithium3 & 3 & 1952 & 4000 & 3293 \\ Dilithium5 & 5 & 2592 & 4864 & 4595 \\ Falcon-512 & 1 & 897 & 1281 & 666 \\ Falcon-1024 & 5 & 1793 & 2305 & 1280 \\ SPHINCS+SHA2-128f-simple & 1 & 32 & 64 & 17,088 \\ SPHINCS+SHA2-128s-simple & 1 & 32 & 64 & 7856 \\ SPHINCS+SHA2-192f-simple & 3 & 48 & 96 & 35,664 \\ SPHINCS+SHA2-192s-simple & 3 & 48 & 96 & 16,224 \\ SPHINCS+SHA2-256f-simple & 5 & 64 & 128 & 49,856 \\ SPHINCS+SHA2-256s-simple & 5 & 64 & 128 & 29,792 \\ SPHINCS+SHAKE-128f-simple & 1 & 32 & 64 & 17,088 \\ SPHINCS+SHAKE-128s-simple & 1 & 32 & 64 & 7856 \\ SPHINCS+SHAKE-192f-simple & 3 & 48 & 96 & 35,664 \\ SPHINCS+SHAKE-192s-simple & 3 & 48 & 96 & 16,224 \\ SPHINCS+SHAKE-256f-simple & 5 & 64 & 128 & 49,856 \\ SPHINCS+SHAKE-256s-simple & 5 & 64 & 128 & 29,792 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Available algorithms specifications [19].  
\begin{table}
\begin{tabular}{l l} \hline \hline
**Parameter** & **Description** \\ \hline WMWare version & VMWare Workstation 16 \\ Operating system & Ubuntu 22.04.1 LTS \\ Memory & 12 GB \\ Processors & 8 cores \\ Host processor & Intel Core i7-9750H CPU @ 2.60 GHz \\ Disk space & 30 GB SSD \\ \hline \hline \end{tabular}
\end{table}
Table 2: Technical specification of the virtual machine.  
Figure 2: Signature and correct verification.