esa-sceva/satcom-chunk-collection huggingface dataset:
# Numerical Study on the Evolution Mechanism of the Crater under a Millisecond Laser
###### Abstract  
A two-dimensional numerical model considering recoil pressure and Hertz-Knudsen ablation rate was established on the foundation of the laser remelting model to investigate the influence of laser processing parameters on crater feature and melted zone, and it was verified through experiments. The temperature and flow velocity distribution of the molten pool during the formation of the crater were analyzed. The results showed that the ablation velocity could be considered under a higher laser peak power density or higher pulse width due to the metal evaporation caused by heat accumulation. The depth and diameter of the crater were significantly affected by laser peak power density and laser pulse duration. Simultaneously, the height of the edge bulge decreased with the increase in pulse duration after 1.5 ms, and the growth rate of central depth was more rapid than that of edge bulge height with the increase of laser peak power density. In the texture with the same depth, a larger melted zone could be obtained with a longer laser duration than the higher peak power density.  
**Keywords:** crater morphology; ablation rate; numerical simulation; melted zone; millisecond laser
## 4 Experimental Research
### Comparison of Multi-Feature Extraction Methods  
To compare IMFE with the nonlinear dynamic methods and the classical feature extraction methods, some experiments were conducted on a public dataset using SVM as a classifier.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Feature Extraction Method** & **Classifier** & **Top Classification Rate (\%)** & **Average Classification Rate with 10-Fold CV (\%)** \\ \hline MFE & SVM & 100 & 90.36 \(\pm\) 2.67 \\ IMFE & SVM & 100 & 92.14 \(\pm\) 2.1 \\ \hline \hline \end{tabular}
\end{table}
Table 2: The influence of parameter optimization in MFE on recognition rate.  
Figure 9: For \(\tau=4\), the mean and standard deviation of FED curves for input variables (**a**) embedding dimension \(m\); (**b**) boundary gradient \(n\); and (**c**) boundary width \(r\).
## 2 What Is Terrestrial Storage of Biomass (TSB)?
### The Case for TSB as a Simple, Natural, Carbon-Efficient, and Low-Cost NET Technology  
Compared to other NETs, TSB has few drawbacks. The high-level advantages of TSB are provided here. More depth is provided below.  
TSB is simple. It only requires segregating the topsoil to remove the bacteria and organisms that act as catalysts for degradation, excavating the clay below to form burial pits, filling them with the biomass, and then surrounding them with the clay from the excavation to minimize the degradation.  
TSB is natural. Nature does the work of removing the CO\({}_{2}\) from the atmosphere by growing biomass via photosynthesis.  
TSB is carbon efficient. The Puro.Earth Standard \"Terrestrial Storage of Biomass (TSB) Methodology for CO\({}_{2}\) Removal Edition 2023\", June, 2023\" (Puro.Earth [42]), based on the \"2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories\" from the IPCC [43], suggests that less than 8.8% of the asymptotic degradation of feeds meeting the definition of woody biomass can be expected with proper burial pit designs.  
TSB is low-cost. The current targeted feedstock is low-cost logging or agricultural waste. Logging waste includes wood slash, such as branches and roots, that would normally be burned, thus releasing their carbon back into the atmosphere. Some states are beginning to ban wood slash burning, such that loggers may be willing to pay to take the feedstock rather than pay tipping fees to send it to landfills. If the burial pits are close to the feedstock source, the transportation cost is low, and the cost of renting and operating the excavation equipment is low, this will be associated with low emissions for the overall process life cycle analysis.  
The Chemistry of Biomass Formation and Degradation and Steps That Can Be Taken to Minimize Degradation  
Understanding the chemistry of biomass formation and lignocellulosic decomposition provides clues on how degradation can be minimized, and the less than 8.8% asymptotic degradation assumed in the Puro.Earth standard can be achieved.  
The chemistry of the decomposition of buried biomass will essentially be the same as the decomposition of biomass in municipal landfills. The key concern for biomass burial is methane formation. The decomposition of buried biomass undergoes several distinct chemistry phases in sequence before it reaches a methane-forming phase. Once the methane formation phase is reached, biogas generation begins to undergo an exponential decline, which can be modeled by the LandGem model of the US EPA [44]. Thus, as time approaches infinity, the rate of biogas generation during the methane-forming phase goes to zero, and landfills are known to become dormant. This leads to an asymptotic fraction of the total buried biomass that decomposes to less than one, and an asymptotic total amount of methane formed. Understanding the chemistry of each distinct phase of decomposition provides opportunities to interrupt each phase and thus minimize the asymptotic amount of methane that will form.
## 2 Literature Review on LMI Applications in Rehabilitation Robotics
### Added Value of LMI-Based Methods in Rehabilitation Robotics  
The integration of LMI techniques in rehabilitation robotics provides robust solutions to challenges such as nonlinear dynamics, uncertainty management, and dynamic human-robot interactions [43; 44; 45]. Tools such as MATLAB's LMI toolbox and Lyapunov stability theory ensure stability and adaptability across varying operational conditions while optimizing performance over extended usage periods [40]. Additionally, LMI-based controllers excel in modeling and effectively addressing disturbances, making them particularly well-suited for rehabilitation applications, as evidenced by their increasing adoption in both simulation and experimental settings.  
Furthermore, recent studies have shown significant impacts of LMIs in the design of robust controllers for increasingly sophisticated rehabilitation devices, particularly exoskeletons and other robotic assistance systems [46; 47; 48]. The extension of recent research into diverse contexts, along with experimental validation, suggests that LMI techniques will continue to play a central role in the development of robotic rehabilitation technologies [38; 49; 50].
## 4 Salinity Origin and Its Impacts on Plants
### Primary Metabolism
#### 4.2.2 Respiration  
Respiration and mitochondrial metabolism ensure a central function in establishing plant salinity resistance like ion removal, osmotic resistance, and ROS (reactive oxygen species) responses [72]. Salinity has been shown to contribute to increased respiration levels in a large variety of plant species [73; 74]. In some cases, the increase in the respiration rate is related with changes in the plasmalemma composition and permeability, higher protein turnover [75], and higher energetic costs associated with ion homeostasis. Nevertheless, respiration itself can be inhibited by salinity through distinct sensitivity of the enzymes involved in the respiration pathway towards salinity [76; 77]. For example, salt treated wheat leaves exhibit higher respiration rate and extensive metabolite changes. The activity of the tricarboxylic acid (TCA) cycle enzymes pyruvate dehydrogenase complex and the 2-oxoglutate dehydrogenase complex were shown to be directly salt sensitive. Multiple lines of evidence showed that the \(\gamma\)-aminobutyric acid (GABA) shunt was activated under salt treatment [78].
## 5 Discussion
### Fault Current-Limiting Ability Comparison  
To investigate the FCL ability, the bias voltage adopted in the scheme presented in Reference [15] is omitted for convenience, and the values of the FCL reactor and energy dissipation resistance are maintained in comparison with the FCL ability (\(R_{FCL}=20\)\(\Omega\), \(L_{FCL}=250\) mH). In accordance with the FCL method in Reference [21], the AC feeding current can be limited via a parallel-connected thyristor, and the FCL ability is compared on the basis of the capacitor discharging current in the present study. Therefore, the AC feeding current is eliminated by switching off the start connector in the simulation while the DCCB operates. The simulation results of the arm and DC line currents with different FCL schemes are compared, as exhibited in Figure 19. The arm current with the resistance-based method (R-method) is limited to approximately 6 kA (Figure 19a). The arm currents with inductance-based method (I-method) and proposed scheme are restricted under 2 kA (Figure 19c,e, respectively). The proposed method can accelerate the fault current decay while the main breaker opens. Thus, the freewheeling diodes and IGBTs can be protected from overcurrent for a long time, and the fault current isolation speed is shortened. The R-method has the worst FCL performance, thereby limiting the DC line current to approximately 18 kA (Figure 19b). By contrast, the I-method and the proposed method can restrain the DC line current under 5.5 kA (Figure 19d,f, correspondingly). However, the DC line current with the I-method remains at a high level after the main breaker opens. In summary, the proposed scheme has an improved performance in limiting the fault current through converter arms and DC line.
# High-Power Broadband Frequency Chirped Intensity-Modulated Single-Frequency 1064-nm Laser
## 3 Theoretical Optimization of Diode Laser Pumped YDFA  
The modulated laser beam was amplified by an YDFA. The rate equations of the pump and signal light in a gain fiber are as follows [16]:  
\[\frac{dP_{p}(z)}{dz}=\Big{[}(\sigma_{P}^{e}+\sigma_{P}^{a})N_{2}(z)-\sigma_{P }^{a}N\Big{]}P_{P}(z)\Gamma_{P}-\alpha_{P}P_{P}(z), \tag{5}\]  
\[\frac{dP_{S}(z)  
light, respectively. \(N\) is the doping concentration of Yb\({}^{3+}\) and \(N_{2}(z)\) is the concentration of upper energy-level particles, which has the expression [17,18]:  
\[\frac{N_{2}(z)}{N}=\frac{\frac{\frac{\sigma_{p}^{a}}{\hbar\
u_{p}}P_{p}(z)\Gamma _{P}+\frac{\sigma_{s}^{a}}{\hbar\
u_{S}}P_{S}(z)\Gamma_{S}}}{\frac{\sigma_{p}^ {a}+\sigma_{p}^{a}}{\hbar\
u_{p}}P_{p}(z)\Gamma_{P}+\frac{\sigma_{s}^{a}+\sigma _{s}^{a}}{\hbar\
u_{S}}P_{S}(z)\Gamma_{S}+A_{core}/\tau_{21}}, \tag{7}\]  
where \(\
u_{p}\) and \(\
u_{S}\) are the optical frequencies of the pump and signal, and \(h\) is the Planck constant.\(\tau_{21}\) is the lifetime of upper energy-level particles, and \(A_{core}\) is the cross-section of the fiber core, respectively.  
A double-clad fiber with a 0.5% ytterbium-doping concentration was used as the gain fiber. The core diameter of the gain fiber was 25 \(\upmu\)m and the inner cladding diameter was 250 \(\upmu\)m. Figure 1 shows the dependence of the amplified power with respect to the fiber length at different pumps and signal powers. It is shown that at a certain pump power, there is an optimum fiber length, and the optimum fiber length increases slightly with the increase of the pump power. In our system, the maximum pump power available was 40 W, and the output curve is flat from 12 to 15 m, so we chose 12 m as the fiber length. On the other hand, the input signal also contributes to the final amplified output. If the signal power is too small, even if the pump power is very high, the weak signal cannot extract the gain stored in the fiber and it is difficult to obtain a high power output. As the modulated laser signal had only 10.4 mW power, we decided to use a two-stage amplifier structure. The first stage amplified the signal light power to the watt level before going to the second stage of amplification.
## 2 System Model and Problem Formulation
### System Description  
In Figure 1, we investigate a covert communication system based on ISMTRN with partial relay selection, consisting of a satellite \(S\), a legal user \(U\), and \(N\) DF relays, represented by \(R_{i}\) (\(i=1,\ldots,N\)). All nodes are equipped with a single antenna and work in half-duplex mode. Besides, it is assumed that the direct link between the satellite and the user cannot be achieved due to deep channel fading. In our model, we consider the scenario that while forwarding the satellite's source information, the selected relay opportunistically transmits its information to the destination covertly. Meanwhile, the satellite acts as a monitor.  
The channel coefficient of the link \(a\to b\) (\(a,b\in\{S,R_{i},U\}\)) is defined as \(h_{ab}\), which is an independent, zero-mean complex Gaussian random variable with unit variance. In order to make the analysis concrete, it is assumed that there are discrete-time channels with \(T\) time slots between each node, and each time slot has \(n\) symbol periods. Moreover, we consider that the channels within this system experience block fading, representing that channel coefficients in each time slot remain constant but vary independently from one-time slot to another. Furthermore, it is assumed that \(i\)th relay \(R_{i}\) only knows its own \(h_{SR_{i}}\) and \(h_{R_{i}U}\), while \(S\) knows all \(h_{SR_{i}}\) and \(U\) knows all \(h_{R_{i}U}\)[29]. Finally, we assume that the satellite-terrestrial relay links are modeled by Shadowed-Rician (SR) fading, and relay-user links follow the Rayleigh fading. Generally, additive white Gaussian noise (AWGN) (\(\mathcal{CN}\big{(}0,\sigma^{2}\big{)}\)) interferes with all nodes.
# Delivering Extended Cellular Coverage and Capacity Using High-Altitude Platforms
###### Abstract  
Interest in delivering cellular communication using a high-altitude platform (HAP) is increasing partly due to its wide coverage capability. In this paper, we formulate analytical expressions for estimating the area of a HAP beam footprint, average per-user capacity per cell, average spectral efficiency (SE) and average area spectral efficiency (ASE), which are relevant for radio network planning, especially within the context of HAP extended contiguous cellular coverage and capacity. To understand the practical implications, we propose an enhanced and validated recursive HAP antenna beam-pointing algorithm, which forms HAP cells over an extended service area while considering beam broadening and the degree of overlap between neighbouring beams. The performance of the extended contiguous cellular structure resulting from the algorithm is compared with other alternative schemes using the carrier-to-noise ratio (CNR) and carrier-to-interference-plus-noise ratio (CINR). Results show that there is a steep reduction in average ASE at the edge of coverage. The achievable coverage is limited by the minimum acceptable average ASE at the edge, among other factors. In addition, the results highlight that efficient beam management can be achieved using the enhanced and validated algorithm, which significantly improves user CNR, CINR, and coverage area compared with other benchmark schemes. A simulated annealing comparison verifies that such an algorithm is close to optimal.  
Keywords:high-altitude platform; beam pointing; coverage; capacity; spectral efficiency; area spectral efficiency +
Footnote †: journal: Electronics Letters
## 2 Materials and Methods  
### Experimental Site  
The study was conducted with the experimental field platform designed for the continuous measurement of vegetation fluorescence at the \"Institut National de la Recherche Agronomique\" (INRA) site located in Montfavet near Avignon, France (43\({}^{\circ}\)55\({}^{\prime}\)3.24\({}^{\prime\prime}\)N, 4\({}^{\circ}\)52\({}^{\prime}\)46.60\({}^{\prime\prime}\)E). The site is equipped with a movable crane, which can translate between two contiguous field plots of 100 \(\times\) 200 m\({}^{2}\) and 60 \(\times\) 150 m\({}^{2}\). Additional information on the site and instrumental equipment can be found in [32]. The two plots were sowed with winter wheat (_Triticum turgidum durum_, cultivar Daker) on 19 November 2009, with a plant density of 338 plants/m\({}^{2}\) and a distance between rows of 14.5 cm. Measurements were carried out from 3 March 2010 (day of year (DOY) 62) to 16 June 2010 (DOY 167). This time period goes roughly from the end of the tillering phase to the end of grain filling (Figure 1).
# Empirical Study of Fully Homomorphic Encryption Using Microsoft SEAL
## 1 Introduction
This comparison not only illustrates the specific computational and memory constraints of edge devices but also emphasizes the need for algorithmic improvements to ensure the viability of FHE in such contexts. In addition, our work could serve in addressing real-world implementation by bridging the theoretical aspects of cryptographic advancements with their practical application implications. The rest of the paper is organized as follows. Section 2 presents a brief on the state of the art in FHE use and the main libraries available. Section 3 describes the research methodology. In Section 4, we showcase and discuss the results. The paper ends summarizing the most important outcomes.
## 3 Result and Discussion
### Engine Performance  
#### 3.6.1 Engine Brake Power  
Power is defined as the rate of work done by the engine. Specifications of biodiesel, especially in heating value, lubricity, and viscosity have an important effect on engine power. By using the high concentration rate of biodiesel, the engine brake power (BP) increases. The improvement in engine power can be attributed to the increase in the indicated mean effective pressure for higher biodiesel concentration [70]. The heat evaporation of biodiesel fuel is higher than diesel fuel; this characteristic provides fuel-air charge cooling and increases the density of the charge. Thus, higher power output is obtained [71]. The variation of BP with diesel-biodiesel fuels is shown in Figure 5. Improvement in BP is observed with the increase of biodiesel concentration. The highest BP is observed for B20 at the full load.
# A Systematic Review of Ship Wake Detection Methods in Satellite Imagery
## 3 Results
### Overview of Traditional Methods of Wake Detection
#### 3.2.1 Methods Based on the Extraction of Linear Features
By applying Floquet theory, the T-matrix method, and the extended boundary condition method (EBCM), they derived the scattering cross-section formula for a finite periodic dielectric surface representing the Kelvin arms. Their simulations analyzed how ship speed, shape parameters, and incident angles influenced the scattering intensity distribution of the wakes. Most of the studies referenced above only focused on a relatively small manually selected subset or localized data from their respective imagery. Moreover, transforms are often applied locally, sometimes after hull detection [12]. Indeed, the issue of false alarms and failed detections due to surface marine phenomena significantly reduces the range of successful applicability of these traditional methods of detection. In this sense, the DL-based methods analyzed in the following section have a powerful advantage, in that they are able to learn hidden and complex patterns at various scales in the data, as long as enough properly annotated data are provided for their training. Regardless of the issues with these methods, knowledge of them is an important starting point. Tools such as RT are powerful in their simplicity and can be integrated into DL-based wake detection processing chains to improve their performance [10].
## 3 Results
### End Notch Flexure (ENF)  
Regarding the ENF samples, Figure 7 shows the relationship between displacement and the mode II critical energy release rate GIIC at failure for each sample that was doped and undoped. The average GIIC value for each condition was 503 \(\pm\) 46 J/m\({}^{2}\) and 564 \(\pm\) 37 J/m\({}^{2}\), respectively, showing an increase of 12% for the doped adhesive. The strengthening of adhesive bonds with the addition of hard ceramic nanoparticles (such as Al2O3, ZnO, and TiO2) is well documented [24; 25; 26; 27; 28; 29]. These samples experienced cohesive failure, and the addition of the nanoparticles did not seem to impact the type of failure in lap shear testing. This study shows how adhesive joints containing MENs show an increase in mechanical performance compared to undoped joints. The increase in the critical energy release rate can be modeled using the formulation discussed in [PERSON] et al. [27], in which the GIIC of a particle-toughened polymer adhesive can be determined using the GIIC of the adhesive (values obtained from ENF testing above) and the change in energy required for plastic zone growth. This energy can be obtained from the mechanical properties of the ceramic (EMENs = 50 GPa [30]), the volume fraction of the nanoparticles (1 vol%) and voids, and the plastic zone radius of the unmodified polymer. Based on these inputs, the range of the expected critical energy release rate as a function of MEN addition was calculated to be between 546 J/m\({}^{2}\) and 553 J/m\({}^{2}\), which slightly under-predicted the experimental GIIC values found with ENF testing (average of 564 J/m\({}^{2}\)).  
Figure 6: (**a**) Peak stress of undoped and doped adhesives for single lap shear samples; (**b**) load-displacement curves for undoped (black) and doped (red) samples.  
Figure 7: GIIC of undoped and doped adhesives with 1 vol% MENs.  
In addition, a JEOL JIB-4500 Dual Beam FIB-SEM was used to take in situ images and a video of the failure of one doped ENF sample, which are included as Figure 8 and Video S1. Imaging shows localized shear loading, plastic zone evolution, and failure of the ABCJ in the crack tip region. As indicated by the blue arrows, localized damage was seen to occur outside the plastic zone in the form of visible microcracking resulting from the distribution of loading away from the pre-crack. In addition, the red arrows identify the initial formation microvoid cluster in the high-shear region. The fracture surfaces of the failed specimen showed similar plastic zone development in the failure and crack tip regions for plain samples and samples containing MENs. The most likely toughening mechanisms, in this case, are stress shielding of the crack tip and localized stress transfer to the stiffer nanoparticle [31].