esa-sceva/satcom-chunk-collection huggingface dataset:
## 1 Introduction  
Calibration of ultra-low-frequency (ULF) (below 0.1 Hz) vibration is urgently needed in various fields including aerospace engineering, precision machining and manufacturing, structural dynamic analysis, earthquake forecast, sea-wave monitoring and warning, mineral exploration, etc. [1; 2; 3]. However, it is quite difficult due to a variety of reasons, especially the lack of the high-precision vibration exciter that can generate ULF standard vibration with very low acceleration waveform harmonic distortion (AWHD) [4]. For the development of the high-precision low-frequency electromagnetic vibration exciter, high-performance magnetic circuit offering uniform magnetic flux density (MFD) along the long stroke (above 1 m) is essential [5], which is also the technological know-how of a couple of vibration exciter manufacturers in the world. Although the performance advantages of closed double magnetic circuits (CDMCs) have been demonstrated [6; 7; 8], on the one hand, it places extremely high demands on permanent magnet (PM) material and the precision of machining and assembly, and on the other hand, theoretical modeling for the structure design is demanding.  
Compared to short stroke magnetic circuits, great difficulty in theoretical modeling is presented in developing an ultra-long stroke CDMC for an ULF metrological vibration exciter. The reluctance caused by the yokes, which is ignorable in short-stroke magnetic circuits [9; 10; 11; 12], becomes a key factor limiting the uniformity of MFD distribution. The MFD curve which is approximately a straight line in short-stroke magnetic circuits is of an obvious basin shape. On the other hand, to achieve high and uniform MFD along long stroke and low acceleration waveform harmonic distortion, the requirement for modeling precision is much higher than normal electrodynamic actuators. Currently, there is very little literature on high-accuracy theoretical models for long-stroke CDMCs. He et al. proposed a lumped parameter magnetic equivalent circuit (LPMEC) model [7] to analyze a cylindrical CDMC based on Kirchhoff's law and the superposition theorem. As the reluctance in the yoke is difficult to express, and the MFD varies along the radial direction, the established model is limited. Meanwhile, the strong nonlinear characteristics of yokes and magnetic flux leakage in the CDMC bring extra difficulty in solving model equations [10; 13; 14; 15; 16; 17]. Therefore, only qualitative conclusions rather than precise quantitative parameters or characteristic curves were obtained.  
In this paper, a patented rectangular closed double magnetic circuit (RCDMC) [18; 19] offering ultra-long stroke for ULF vibration exciter is proposed. A high-accuracy theoretical modeling method is proposed through the LPMEC method taking advantage of structural symmetry. The model is solved by iteration calculation and verified through comparison with the finite-element method (FEM). Model-based optimization and experimental verification are carried out. Finally, a vibration exciter with a stroke up to 1.2 m is realized.
## 3 Multi-Failure Mode Tunnel System Analysis Model
### Numerical Analysis of High-Pressure Tunnel
#### 3.2.3 Model Components and Mesh Division  
The calculation model size is 930 m \(\times\) 750 m \(\times\) (560-880) m. In order to clearly describe the spatial relationship, the center of the high-pressure tunnel is the origin of the model. The \(X\)-axis is perpendicular to the tunnel axis direction, the \(Z\)-axis is the tunnel excavation direction, and the \(Y\)-axis is the vertical direction. In order to ensure the accuracy and stability of the calculation, the surrounding rock includes 253,168 tetrahedral units and 1,023,527 nodes, and the lining includes 23,162 hexahedral units and 53,308 nodes. The  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Name**} & **Elastic** & **Poisson** & **Cohesive** & **Internal Friction** & **Permeability** & **Unit Weight** & **Compressive** \\  & **Modulus** & **Ratio** & **Force \(c\)** & **Angle \(\varphi\)** & **Coefficient** & **m/s** & **g/cm\({}^{3}\)** & **Strength** \\  & **GPa** & **\(v\)** & **MPa** & \(\circ\) & **m/s** & **g/cm\({}^{3}\)** & **MPa** \\ \hline Class III & & & & & & & & \\ surrounding rock & 11.25 & 0.24 & 1.1 & 42.5 & \(3.5\times 10^{-7}\) & 2.66 & 83 \\ Class IV & & & & & & & & \\ surrounding rock & 5.5 & 0.28 & 0.75 & 36.5 & \(2.8\times 10^{-6}\) & 2.63 & 20 \\ FL4 fault & 1.5 & / & 0.4 & 23.5 & \(4.5\times 10^{-5}\) & 2.1 & / \\ Concrete & 33 & 0.17 & / & / & \(3.5\times 10^{-9}\) & 2.5 & 45 \\ Anchor & 210 & 0.3 & / & / & / & 7.8 & 335 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Information on the material’s physical and mechanical parameters.  
Figure 5: Survey and location map of studied area [27].  
computational grid model is shown in Figure 6. The blue-green part of the model represents strongly weathered rock mass, and the red part represents Class III surrounding rock; due to the small width of the fault, in order to facilitate viewing, Figure 6a was locally enlarged, with the gray area representing the fault zone.
# Winter Wheat Mapping in Shandong Province of China with Multi-Temporal Sentinel-2 Images
## 2 Materials and Methods
### Data Used  
#### 2.2.1 Satellite Data  
The Sentinel-2 series of Earth observation satellites is an important part of the Copernicus program promoted by the European Space Agency (ESA) and the European Commission [36]. The observation of the Earth's surface to provide relevant telemetry services is its main operational mission. Sentinel-2 has two satellites, Sentinel-2A and Sentinel-2B, which were launched and put into operation in 2015 and 2017, respectively [37]. Each satellite in the Sentinel-2 series carries the same multi-spectral instrument (MSI), a sensor that covers reflectance data in 13 wavelength bands from the visible, near-infrared to the short-wave infrared, enabling the acquisition of multi-resolution, multi-spectral remote sensing images [38; 39]. The revisit cycle is shortened to 5 days when both satellites are working simultaneously. In mid-latitude regions with better observation angles, the satellite revisit period can be reduced to 2 to 3 days, which is very favorable for constructing long-time sequence images [40; 41].
# Medium Access Control Protocols for Cognitive Radio Ad Hoc Networks: A Survey
## 3 Survey of State-Of-The-Art MAC Protocols  
Traditionally, the MAC sub-layer is at the link layer, where the link layer is in charge of the communication between adjacent nodes. Therefore, the purposes of the CRAHN MAC protocol not only include the enhancement of channel use and throughput, but also include the mechanism of spectrum controlling modules; for example, spectrum sharing and spectrum access tasks to find the technique for data transmissions [61; 62]. Thus, an efficient MAC protocol must address the sensing, access and mobility of the spectrum, which are the main functions of the cognitive cycle.  
In the following subsections, the existing MAC protocols are categorized based on their medium access scheme; these schemes are random access, time-slotted and hybrid (combination of random access and time-slotted schemes). In this section, the popular approaches in each scheme are introduced, and the advantages and disadvantages of each protocol are discussed. Figure 3 shows the MAC protocols that are considered in this paper.
## 9 OCTA in Geographic Atrophy  
Geographic atrophy (GA) represents the advanced form of dry AMD, and it affects more than 5 million people worldwide [4]. GA is characterized by the degeneration of photoreceptor cells, RPE, and CC. Usually, in the early stages of the disease, it involves the extrafoveal region and then includes the fovea, limiting daily activities and impairing quality of life [98; 99; 100; 101].  
GA is commonly assessed by color fundus photography and fundus autofluorescence (FAF), which is considered the gold standard for the evaluation of progression of atrophy enlargement [102; 103; 104].  
Recently, several studies conducted using OCTA showed that the atrophic patches present a loss of choriocapillaris flow and an improved visualization of choroidal vessels [105]. In particular, GA appears with loss or rarefaction of CC at the level of RPE atrophy [105; 106]. In these areas of CC impairment, large choroidal vessels may be displaced and may be seen on the en face OCTA image at the depth level where CC is ordinarily seen [105]. [PERSON] et al. demonstrated that OCTA is an effective technique for the visualization and quantification of GA lesions [107]. Evaluating 47 eyes affected by GA, they showed that OCTA can quantify the area of atrophy as FAF and en face OCT [107].  
Another advantage of OCTA is the ability to evaluate the CC status of eyes with GA. [PERSON] et al. firstly reported a quantitative CC impairment surrounding the GA margin before RPE alterations observed using FAF, assuming a \"_primum movens_\" at the level of the CC [37]. Moreover, the same group and others showed a greater CC impairment in the area that subsequently developed GA expansion, suggesting that the impairment of CC flow could predict the enlargement of the atrophic lesion [24; 108; 109]. For this reason, OCTA showed that the CC impairment could be considered as a new a risk factor for GA progression and a biomarker to be measured to determine the efficacy of new interventions aiming to slow the progression of GA.  
Finally, OCTA results useful in the evaluation of patients affected by GA in order to exclude the presence of treatment-naive nonexudative MNV. [PERSON] et al. firstly reported the presence of nonexudative MNV in patients affected by GA, showing outcomes and follow-up of 19 eyes [110]. In detail, the authors reported a rate of activation of 26% during a follow-up of 45.7 \(\pm\) 14.7 months. In this way, OCTA play an important role in the diagnosis and follow-up of patients affected by nonexudative MNV and GA.  
In conclusion, the benefits of using OCTA compared with other imaging approaches for GA include the convenience of using only one type imaging technique for showing en face flow images and structural OCT data, the quantification of GA area, and the potential ability to exclude the presence of MNV without performing fluorescein angiography, particularly in treatment-naive nonexudative type 1 MNV.
# Near Real-Time Extracting Wildfire Spread Rate from Himawari-8 Satellite Data
## 4 Results  
### Burned Area Variation  
The total burned area obtained from the Himawari-8 for fire event that was studied (6 h, 10 min time periods) was 1090.62 km\({}^{2}\). The variation in the burned area fluctuated from 0 km\({}^{2}\)/10 min (11:30-11:40 and 12:20-12:30 periods) to 41.35 km\({}^{2}\)/10 min (13:10-13:20 period) before 13:20 AWST with an average rate of (13.44 km\({}^{2}\)/10 min) (Figure 3). However, it rapidly increased thereafter, achieving a peak value close to 90 km\({}^{2}\)/10 min at AWST 15:30-15:40 and 15:50-16:00 (Figure 3).
# Deduplication-Aware Healthcare Data Distribution in IoMT
###### Abstract  
As medical sensors undergo expeditious advancements, there is rising interest in the realm of healthcare applications within the Internet of Medical Things (IoMT) because of its broad applicability in monitoring the health of patients. IoMT proves beneficial in monitoring, disease diagnosis, and better treatment recommendations. This emerging technology aggregates real-time patient health data from sensors deployed on their bodies. This data collection mechanism consumes excessive power due to the transmission of data of similar types. It necessitates a deduplication mechanism, but this is complicated by the variable sizes of the data chunks, which may be either very small or larger in size. This reduces the likelihood of efficient chunking and, hence, deduplication. In this study, a deduplication-based data aggregation scheme was presented. It includes a Delimiter-Based Incremental Chunking Algorithm (DICA), which recognizes the breakpoint among two frames. The scheme includes static as well as variable-length windows. The proposed algorithm identifies a variable-length chunk using a terminator that optimizes the windows that are variable in size, with a threshold limit for the window size. To validate the scheme, a simulation was performed by utilizing NS-2.35 with the C language in the Ubuntu operating system. The TCL language was employed to set up networks, as well as for messaging purposes. The results demonstrate that the rise in the number of windows of variable size amounts to 62%, 66.7%, 68%, and 72.1% for DSW, RAM, CWCA, and DICA, respectively. The proposed scheme exhibits superior performance in terms of the probability of the false recognition of breakpoints, the static and dynamic sizes of chunks, the average sizes of chunks, the total attained chunks, and energy utilization.  
Keywords:data collection; deduplication; cloud and fog computing; healthcare; Internet of Things (IoT) +
Footnote †: journal: _Mathematics_
## 3 Methods  
The aim of this study is to conduct an in-depth analysis of the seasonal variations in the CI and to develop a phenologically simplified two-stage MODIS CI product that can provide global long time series pixel-by-pixel CIs with typical values of seasonal variations based on the MODIS 8-day CI product, thereby offering an effective reference for the modeling of various types of ecological, meteorological, and other surface processes. The general flow chart is shown in Figure 2. The study includes three parts: (1) due to the uncertainties in the CI inversion process, this study uses the more stable NDVI as a reference for comparison, estimates the phenological parameters of the CI and NDVI time series in the mid-to-high latitudes of the Northern Hemisphere (23.5\({}^{\circ}\)N-60\({}^{\circ}\)N) to identify CI seasonal variations relative to the NDVI; (2) determining the algorithm for developing the MODIS time-share two-stage CI product and evaluating its accuracy; and (3) exploring the seasonal differences in CI values and their spatiotemporal characteristics on the basis of the MODIS time-share two-stage CI product.  
Figure 1: Distribution of collected field CI measurements (red dots) and typical pixels (white triangles) for all IGBP classes at the global scale. These datasets are mainly distributed along the mid-latitudes where vegetation seasonality tends to be easily identified.
## 3 Results  
### Fundamental Phonatory Parameters  
Table 2 provides an overview of the various fundamental phonatory parameters such as fundamental frequency f0 (Hz), subglottal pressure P5 (Pa), glottal air flow (mL s\({}^{-1}\)), flow resistance R8 (Pa s\({}^{-1}\)), and intensity SPL (dB) with the corresponding mean values, minimum and maximum values.  
In this study, data of 51 test runs were used. Of these, 35 test runs contained subharmonic (Groups) and 16 test runs aperiodic oscillations (GroupA). As Table 3 shows, the subharmonic and aperiodic oscillations occurred at all airflow intensities (different airflow levels) and elongation levels (different weight levels), but tended to increase with higher air flow and higher elongation.  
Figure 7a shows the fundamental frequencies of the GAW, subglottal pressure signal and acoustic signal for the subharmonic oscillations. Figure 7b shows this correspondingly for the aperiodic oscillations. The GAW signals show the lowest mean fundamental frequency; see Figure 7a (353 Hz) and Figure 7b (482 Hz). This is followed by the mean fundamental frequency of the subglottal pressure data at 696 Hz (Figure 7a) and 635 Hz (Figure 7b). The highest mean fundamental frequency was found for the audio measurements at 850 Hz (Figure 7a) and 978 Hz (Figure 7b). Despite that increasing tendency, the frequencies show considerable fluctuations; see Figure 7a,b.  
\begin{table}
\begin{tabular}{c c c c c} \hline  & **f0 Hz** & **P5 (Pa)** & **Flow (mL s\({}^{-1}\))** & **R8 (Pa s\({}^{-1}\))** & **SPL (dB)** \\ \hline
**Mean \(\pm\) std** & 655 \(\pm\) 147 & 1324 \(\pm\) 798 & 120 \(\pm\) 42 & 11428 \(\pm\) 5631 & 74.3 \(\pm\) 8.9 \\
**Minimum values** & 343 & 196 & 42 & 2587 & 54.7 \\
**Maximum values** & 895 & 3318 & 175 & 21557 & 90.7 \\ \hline \end{tabular}
\end{table}
Table 2: Mean values, minimum and maximum values of the fundamental phonatory parameters.  
\begin{table}
\begin{tabular}{c c} \hline
**Airflow levels** & **\(\Sigma\) = 51** \\ \hline
1 = onset & 3 \\
2–6 = low & 15 \\
7–11 = medium & 11 \\
12–16 = high & 22 \\ \hline
**Weight levels** & **\(\Sigma\) = 51** \\ \hline w1 = 1 g—low & 12 \\ w2 = 2 g—medium & 11 \\ w3 = 5 g—high & 28 \\ \hline \end{tabular}
\end{table}
Table 3: Frequencies of the test-runs divided into the different airflow levels and elongation levels.
## 1 Introduction
In such situations, the conventional no-slip condition must be replaced with slip boundary conditions of the form, \(\overline{u}=N_{1}\tau_{0}\), where \(\overline{u}\) is the tangential velocity, \(\tau_{0}\) is the tangential shear stress and \(N_{1}\) is the dimensional slip factor ([PERSON] [37]), \(T=D_{1}\frac{gT}{\partial y}\) where \(D_{1}\) is the thermal slip factor. [PERSON] et al. [38] investigated the slip effect on a micro-spherical particle. Usually, velocity slip on the wall enhances convection along the surface, while the temperature jump decreases the heat transfer. Hence, neglecting temperature jump resulted in an overestimation of the heat transfer coefficient. Inspection of the literature indicates that the only available study related to the g-jitter mixed convective flow of nanofluids has been presented by [PERSON] et al. [39] who noted that there was a sinusoidal nature exhibited by the Nusselt numbers for both Cu-water and Al\({}_{2}\)O\({}_{3}\)-water nanofluids. This study, however, assumed the nanofluid to be electrically non-conducting. It transpires that magnetohydrodynamic (MHD) mixed convective g-jitter flow in a Darcian porous medium with passively controlled boundary conditions and nonlinear radiation effects has, thus far, not been investigated, and this is the aim of the present analysis. This paper is, therefore, a generalization of the recent work of [PERSON] et al. [39] on Buongiorno-Darcy porous medium g-jitter convection and incorporates nonlinear radiation, magnetic field effects, and zero mass flux boundary conditions. The governing transport equations are reduced to non-similar equations using appropriate transformations. Simulations are then performed using an implicit finite difference method. The computations are validated against special cases with earlier published results. The influence of the emerging parameters on the dimensionless velocity, temperature, nanoparticle volume fraction, friction factor and heat transfer rates are demonstrated clearly with the help of graphs and tables. The analysis is relevant to magnetic nanofluid materials processing transport phenomena.
## 4 Discussion
A similar attempt was presented in References [45; 46]; however, it is not directly applicable as users still need to be knowledgeable in statistical and geospatial sciences. The current platform generalizes and combines all the steps used in these studies to provide researchers, with no computational skills, the opportunity to process the fitting and select the models that can further be projected spatially at the landscape level. **Application:** The Lorentzian 4-parameter model obtained in the application section estimates an optimum temperature for the higher virulence of ICIPE62 in killing the aphid at about 21 \({}^{\circ}\)C. When comparing the current distribution map of the _Lipaplis pseudobrassicae_[40] with the map of the potential zone of the efficacy of ICIPE 62 isolate in Kenya and Cameroon, we observed that many invaded locations fit well with a potential zone of efficacy with virulence level greater than or equal to 0.5. Although the estimates were made without full inclusion of other environmental variables that have impacts on the fungi efficacy in killing insects, the outputs are promising. However, it will be useful to explore the association of temperature with other factors such as relative humidity to improve the accuracy of the prediction, especially for mapping the virulence level of the EPF. Indeed, many studies highlighted the key role played by both temperature and relative humidity in enhancing the virulence of EPF on insect pests [47; 48; 49]. On this note, a good perspective to consider for improving the current tool will be to consider the association of at least two factors (temperature and relative humidity, for example) as independent variables in the fitting process.
## 3 Results and Discussion  
### Biomass Production and Proximate Biochemical Composition  
The biomass production of _A. platensis_ grown with different phosphorus concentrations is illustrated in Figure 1a. As shown, the increase in the phosphorus provided in the cultures resulted in increased biomass production. This indicates that phosphorus was the growth limiting factor for the cultures containing 1.5, 2 and 3 mg-P/L. When _A. platensis_ was cultivated with 4 mg-P/L it produced as much biomass (around 1700 mg/L) as the control (no statistically significant differences), showing that phosphorus did not affect growth of _A. platensis_ at this concentration.  
As shown in Table 1, the proximate biomass composition was significantly affected, in terms of proteins and carbohydrate content, by the amount of phosphorus provided. At the lower P concentrations, there was a strong decrease in protein content (22-25% vs. 60% of the control) and a strong accumulation in total carbohydrates (50-65% vs. 23% of the control) as a consequence of the phosphorus limitation effect [25]. At a phosphorus concentration of 4 mg-P/L, even though the biomass concentration was not affected (Figure 1a), there was a significant difference in the protein and carbohydrate content, indicating that there was still a phosphorus limitation effect compared to the control culture. In terms of carbohydrate productivity (Figure 1b), the best results were obtained with 2 and 3 mg-P/L phosphorus concentration, which gave approximately 145-148 mg/L/d.  
Figure 1: (**a**) Biomass production (dry weight) and (**b**) carbohydrate productivity by _Arthrospin platensis_ cultivated with different phosphorus concentrations (mg-P/L) in semi-continuous mode (daily feeding rate 20%). Each bar represents the average \(\pm\) SD of \(n\) = 3 replicates. The asterisks indicate that there were statistically significant differences between the averages of the sequential cultures.  
One of the main challenges in cultivating microalgae and cyanobacteria under nutrient limited conditions is the trade-off between the accumulation of the target biomolecules triggered by the low availability of the nutrients and the subsequent reduction in biomass production [33]. The results of the present study demonstrate that the process of phosphorus limitation could be optimized in order to cultivate _A. platensis_ in long-term cultivation processes by providing phosphorus at amounts that can support cell multiplication while at the same time triggering the down-synthesis of proteins and accumulation of carbohydrates.