esa-sceva/satcom-chunk-collection huggingface dataset:
# Stabilization of Underactuated Surface Vessels: A Continuous Fractional Power Control Method
## 1 Introduction
### Literature Survey  
To name some, in the reference [4], a discontinuous feedback stabilization control law with \(\sigma\) process was proposed. In the reference [1], [PERSON] presented a discontinuous control law via homogeneous-transformation, which can stabilize the system into a neighborhood of the equilibrium point. Then in the reference [5] an improved scheme was given to increase the convergence rate of the method in the reference [1]. Although these results can stabilize underactuated surface vessels, they are limited by the singular point problem. To deal with this problem, in references [6; 7], switching control methods that can avoid singularity by controlling the convergence rate were proposed. In the reference [8], [PERSON] also gave a switching control law that has no singular point problem.  
The above research works have one thing in common, namely, the control laws are discontinuous and difficult for implementation in engineering systems. Therefore, considerable research attention has been paid to USV stabilization with a continuous control law. For example, in the reference [9], [PERSON] proposed a continuous control law based on backstepping method that can guarantee semi-global asymptotic stability. In references [10; 11], backstepping methods are investigated to ensure global asymptotic stability of USVs. In the reference [12], a simpler backstepping control law is proposed with the aid of a state transformation first presented in the reference [13]. In references [14; 15; 16], backstepping methods are given to asymptotically stabilize the USV system with off-diagonal dynamics and unknown model parameters respectively. Although the methods in references [10; 11; 12; 14; 15; 16] asymptotically stabilize USVs with continuous control laws, backstepping-based control laws are difficult to guarantee convergence rates (especially near the origin). In fact, the second and third methods in the reference [12] can achieve global exponential convergence to the origin; however, they can not guarantee even local asymptotic stability of the origin. Therefore, it is necessary to asymptotically stabilize the system by a continuous method with a faster rate.  
As is well known, fractional power control can improve convergence performance and robustness near the origin [17; 18; 19]. However, most methods of fractional power control cannot be directly used to stabilize USVs, since the dynamics of USVs are strongly nonlinear and coupled. Although in [8], a finite-time switching scheme for stabilizing USVs based on fractional power control was provided, the method is discontinuous. To the best of the authors' knowledge, the stabilization of USVs by continuous fractional power control law has not been solved.
## 6 Numerical Results  
In this section, we demonstrate the performance of the proposed scheme with the help of numerical simulations. We focus on mainly three performance metrics: (i) probability of error; (ii) achievable rates; and (iii) outage probability.
## 1 Introduction
### Mechanism of Fourier Infrared Spectroscopy  
The mechanism of FTIR spectroscopy involves passing IR or signals of lumped frequencies from a polychromatic light source, such as a globar, an incandescent lamp, a nichrome wire, or a Nernst slower, to obtain mid-range IR radiation [16], whereas tungsten-halogen and mercury lamps can produce near and far IR, respectively [17]. The emitted radiation then travels via a collimator and Michelson interferometer (Figure 1), which consists of fixed mirrors, moveable mirrors, beam splitters, and helium-neon (He-Ne) laser beams. The beam splitter could be built of germanium coated with potassium bromide (KBr) and is used to split radiation into fixed and moveable mirrors prior to reflection and indentation on the sample [8]. Connecting the adjustable mirror to the He-Ne laser beam enables precise monitoring of its position, which has a direct correlation with optical path difference (OPD) and radiation amplitude (measured in electron volts) [16; 18; 19]. The amplitude results from constructive interference (in-phase) of returning waves from both the fixed and moveable mirrors, whereas destructive interference (out-of-phase) produces waves with zero amplitude. As depicted in Figure 1, the reflected rays penetrate the sample, absorb a portion of it, and convey the remaining portion to the detectors for interpretation of molecular vibrations in the sample [16; 18]. To attain diffraction-limited resolution in the objective lens, synchrotron radiation is used as a source of photons [11].  
The detector can be made of deuterium triglycine sulfate (pyroelectric detector) or mercury cadmium telluride (photon detector) [17]. The interferogram is then decoded into specific frequencies (wavenumber) using Fourier mathematical transformation [20]. The ratio of the intensity of the sample with blank spectrum (P/Po) and sample thickness (w) gives the transmittance (T).  
As demonstrated in Equations (1)-(3) [21], the transmittance (T) can be represented as a function of the absorption coefficient (\(\alpha_{\text{abs}}\)), and if inverted and transformed to logarithmic values, it becomes the absorbance (A):  
\[\text{T}=\frac{\text{I}}{\text{l}_{\text{o}}}=\text{e}^{-\alpha_{\text{abs}}} \,_{\text{W}} \tag{1}\]  
\[\alpha_{\text{abs}}=\text{log}1-\text{log}\,\text{T} \tag{2}\]where I is the incident light intensity and lo is the transmitted light beam. For weakly absorbing homogeneous samples with known molar absorptivity (\(\gamma\)) and concentration (c), absorbance (A) can be stated as follows:  
\[\text{A}=-\text{logT}=\gamma\text{.c. w} \tag{3}\]
## 2 Core Concepts of Heterogeneous Photocatalysis
### Basic Mechanism of Photocatalysis  
Photocatalytic processes have gained increasing attention for their ability to degrade a broad range of persistent emerging contaminants through light-induced oxidative reactions. These methods typically involve semiconductors such as TiO2 or ZnO, which, upon light irradiation, generate reactive oxygen species (ROS) capable of breaking down complex pollutants into less harmful substances [53; 54]. The fundamental mechanism underlying this process is illustrated in Figure 3, where charge carrier dynamics and contaminant interactions are depicted [55; 56].  
When a semiconductor photocatalyst is irradiated with photons possessing energy equal to or higher than its band gap, electrons (e\({}^{-}\)) in the valence band (VB) are excited to the conduction band (CB), leaving behind holes (h\({}^{+}\)) in the VB (Equation (1)) [57; 58].  
\[\text{Semiconductor}+\text{h}\
u\rightarrow\text{eCB}^{-}+\text{hVB}^{+} \tag{1}\]  
The photogenerated electrons and holes can migrate to the surface of the catalyst, where they participate in redox reactions (Figure 3) [59]. Electrons can reduce dissolved oxygen to form superoxide radicals (\(\bullet\text{O}_{2}{}^{-}\)), while holes can oxidize water or hydroxide ions to produce hydroxyl radicals (\(\bullet\)OH) (Equations (2) and (3)).  
\[\text{O}_{2}+\text{e}^{-}\rightarrow\bullet\text{O}_{2}{}^{-} \tag{2}\]  
\[\text{H}_{2}\text{O}+\text{h}^{+}\rightarrow\bullet\text{OH}+\text{H}^{+} \tag{3}\]  
These reactive oxygen species (ROS), especially \(\bullet\)OH and \(\bullet\)O\({}_{2}{}^{-}\), are highly oxidative and play a central role in the degradation of organic contaminants by breaking chemical bonds and transforming them into less harmful substances or mineralizing them to CO2 and H2O (Equations (4) and (5)).  
\[\text{ROS}+\text{ contaminants}\rightarrow\text{degraded products (indirect oxidation)} \tag{4}\]  
\[\text{Contaminants}+\text{eCB}^{-}+\text{hVB}^{+}\rightarrow\text{reduced}/ \text{oxidized products (direct oxidation)} \tag{5}\]  
The general reactions involved in photocatalytic water purification can be summarized as in Equation (6) [29].  
\[\text{Pollutant}+\bullet\text{OH}/\bullet\text{O}_{2}{}^{-}\rightarrow\text{ Intermediate products}\rightarrow\text{CO}_{2}+\text{H}_{2}\text{O}+\text{Minerals} \tag{6}\]  
The degradation pathway typically involves the formation of transient intermediates, which are further oxidized until mineralization is achieved. Selectivity is often low, leading to non-specific degradation of organic molecules.
# A Bivariate Volterra Series Model for the Design of Power Amplifier Digital Predistorters
## 2 A Bivariate Volterra Series Perspective
### Conventional PA Models
#### 2.1.2 The Circuit-Knowledge Based Volterra Model  
The CKV model, whose detailed methodology is published in [14], is a proposal to identify the kernel structure under the premise of the PA circuit-model knowledge. The reasoning here can be reduced to essentials with an analysis based on the simple PA schematic of Figure 1a, as well as the addition of the electrothermal subnetwork (not shown in the figure). The approach contemplates the derivation of the nonlinear transfer functions including the gate voltage-drain voltage \(v_{g}\)-\(v_{d}\) cross-terms of the nonlinear drain current source and the junction temperature rise acting as the internal variable \(z\). The deduction complies with a standard Volterra series approach to demonstrate the baseband CKV model, given by  
\[y(k)=\sum_{p=1}^{p}\sum_{\mathbf{q}_{p}=0}^{\mathbf{Q}_{p}}h_{2p-1}(\mathbf{ q}_{p})x(k-q_{1})\prod_{r=2}^{p}|x(k-q_{1}-q_{r})|^{2}, \tag{6}\]  
where \(h_{2p-1}(\mathbf{q}_{p})\) is the Volterra kernel with (odd) order \(n=2p-1\), \(\mathbf{q}_{p}=[q_{1},q_{2},\ldots,q_{p}]^{T}\) is a vector of delays of the \(n\)-th order term, and \(\mathbf{Q}_{p}=[Q_{p},Q_{p},\ldots,Q_{p}]^{T}\) is the vector of maximum delays. By definition,\[\prod_{r=2}^{p}|x(k-q_{1}-q_{r})|^{2}=1, \tag{7}\]  
for \(p=1\). Notice that the CKV model in (6) contains a subset of the FV regressors.
# Advanced Medical Image Segmentation Enhancement:
## 3 Materials and Methods
### Dataset Preprocessing
#### 3.2.3 Image Enhancement with Histogram Equalization (HE)  
One of the central aspects of data preprocessing is the application of histogram equalization (HE). This enhancement technique redistributes pixel intensities to achieve a more uniform histogram [92]. Histogram equalization (HE) is employed to improve the contrast and visibility of structures within the images [93]. By enhancing fine details and mitigating  
Figure 4: Sample ground-truth (GT) annotations from the (**a**) lung CT scan and (**b**) chest X-ray COVID-19 datasets.  
non-uniform illumination, HE prepares the images for more accurate segmentation. This step is crucial for ensuring that subtle features and structures are well-visualized and can be accurately delineated during subsequent processing.
## 2 Results and Discussion  
### Chemistry  
According to literature [44], the thiosemicarbazone derivative **3** (obtained from the reaction of \(p\)-anisaldehyde **1** with thiosemicarbazide **2**) reacts with \(\alpha\)-chloro-acetylacetone **4** in refluxing ethanol to afford the acetylcholine derivative **6**. The reaction presumably occurred via the elimination of HCl to afford the intermediate **5A** who tautomerisms into **5B**, which in role, undergoes cyclization via the elimination of water (Scheme 1).  
Figure 1: Examples of anticancer drugs bearing thiazole derivatives.  
The acetylthiaazole **6** was allowed to condense with **2** to afford the thiosemicarbazone derivative **7** Scheme 2). The IR spectrum of **7** revealed absorption band at \(v_{\text{max}}\) = 3402, 3271 and 3201 cm\({}^{-1}\) attributable to NH\({}_{2}\) and NH functions, 3055 and 2954 cm\({}^{-1}\) due to aromatic and aliphatic C-H. The \({}^{1}\)H NMR spectrum of **7** demonstrated two methyl singlets at \(\delta\) = 1.81 and 2.50 ppm, while the methoxy singlet appeared at \(\delta\) = 3.80 ppm, the amino protons at \(\delta\) = 7.75 ppm and two broad amino protons at \(\delta\) = 11.30 and 11.95 ppm, beside the other olefinic and aromatic proton signals at their expected positions (cf. experimental).  
Compound **7** reacted with the hydrazonoyl chloride derivatives **8a-e** to yield the ethylidene hydrazine bis-thiazole derivatives **10a-e** (presumably via the intermediates **9a-e**), respectively.  
To explore the synthetic potentialities of compound **7** and to synthesize another series of bis-thiazoles, it was allowed to react with ethyl hydrazonoyl chloride ester derivatives **11a-e** to afford the ethylidene hydrazine bis-thiazole derivatives **13a-e** [presumably via the intermediates **12a-e**], respectively (Scheme 3). Spectra of IR and \({}^{1}\)H NMR, as well as elemental analysis, are all in full and accord with the depicted structures **10a-e** and **13a-e** (cf. experimental).  
Likewise, compound **7** reacted with \(\alpha\)-chloro acetylacetone **4**, phenacyl bromide **15**, ethyl chloroacetate **17** and dimethyl acetylene dicarboxylate **19** to afford the ethylidene hydrazine bis-thiazole derivatives **14**, **16**, **18** and **20**, respectively (Scheme 4). Spectral and elemental content analyses are consistent with the proposed structures **14**, **16**, **18** and **20** (cf. experimental).  
The geometry of all synthesized compounds **3**, **6**, **7**, **10**, **13**, **14**, **16**, **18** and **20** are in E-configuration [45].
## 2 Background
### MRAM Pulfs  
An early MRAM PUF was proposed in 2014 by [PERSON] et al. [30]. This MRAM PUF proposal uses two STT MRAM cells configured as a single PUF cell to generate their response. The STT MRAM cells are configured to a common state (e.g., high or low) and have their electrical resistance compared to generate a 0 or 1. Additionally, an automatic write-back (AWB) scheme is used; the MRAM cell with the lower resistance is written to 0 and the cell with the higher resistance is written to 1 to improve the BER. The researchers simulated this PUF design and presented an inter-distance of 0.501, an entropy calculation of 0.985, and a BER of \(6.6\times 10^{-6}\). STT MRAM PUF research has been further explored in subsequent studies, such as [17; 31; 32].  
In [17], the approach involved writing all STT MRAM cells to a common state and tuning the reference current to the median of the responses. This resulted in an equal distribution of 0 s and 1 s. Simulation results demonstrated an inter-distance range of 0.499-0.501, entropy ranging from 0.994 to 0.999, and a BER between 0.05 and 0.07.  
In [31], the authors introduced diode-connected transistors to mitigate the effects of deterioration. Simulations of this proposal exhibited an improved BER of 0, with slight variations occurring under different temperature and voltage conditions, resulting in a BER range of 0.0001-0.0004.  
Figure 1: Toggle MRAM (**left**) [29], STT MRAM (**middle**) [29], and SOT MRAM (**right**) [27].  
In [32], the authors put forth an STT MRAM PUF concept that involves comparing the resistances of multiple MTJ cells by passing a current through them. Through simulations, this proposal achieved a BER of 1.56% and a uniqueness metric of 50.0428%.  
Another MRAM PUF design was proposed by [PERSON] et al. in [33]. This design used the geometric variations in MTJs to generate responses. In short, the researchers destabilized the MTJs and then released them, and whichever state (i.e., 0 or 1) the MTJ preferred was used as a response. This design was simulated using stochastic LLG, and the design was found to have an inter-distance of 0.47, an entropy calculation of 0.99, and a BER of 0.0225.  
Moreover, various MRAM-based TRNGs have been proposed in [15; 34; 35; 16; 36]. These MRAM TRNGs use STT and toggle MRAM technology to generate truly random numbers with enough entropy to pass the NIST Testing Suite [37].
## 3 Results
### Data and Experiments
The sampling interval for the vehicle-borne experiment was 1 s, and the coordinates were estimated as white noise with a priori accuracy of 500 m. The atmospheric products from the server were sampled at 5 s intervals and interpolated using linear interpolation to obtain high-precision atmospheric corrections for each epoch and to constrain the normal equations. The constraint accuracies for the slant ionosphere delay and ZWD were 0.1 m and 0.05 m, respectively. \begin{table}
\begin{tabular}{c c} \hline \hline
**Items** & **Description** \\ \hline Frequency & GPS: L1/L2(L5); GAL: E1/E5a(E5b); BDS-3: B1I/B3I(B2a) \\ Observations & Undifferenced and uncombined (UDUC) \\ Intervals & 1 s for rover receiver and 5 s for reference stations \\ Elevation mask & 10\({}^{\circ}\) \\ Cycle slip detection & TurboEdit algorithm and LLI \\ Stochastic model & An elevation-dependent function, where \(b\) is the nominal noise. \\  & \(\sigma_{ele}^{2}=\left\{\begin{array}{ll}b^{2}&ele>30^{\circ}\\ \frac{b^{2}}{4\sin^{2}\theta}&ele\leq 30^{\circ}\\ \end{array}\right.\) \\ Orbit and clock & WUM final products \\ Code and phase OSB & WUM final products \\ Coordinates & Fixed for atmospheric products extraction and estimated as white noise for PPP/PPP-AR/PPP-RTK. \\ Ionosphere delay & Estimated as white noise with sigma of 10 m and constrained by the ionosphere products in PPP-RTK. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of the data processing strategy. Figure 2: CORS distribution in Wuhan region and vehicle driving trajectory. HBA2, HBB0, HBF7, HBE0, and HBH8 were reference stations used to generate atmospheric correction information, while HBA1 was used to verify the atmospheric accuracy of PPP-RTK and conduct static imitating kinematic convergence experiments on PPP-RTK.
# Full-Scale Model Test of Subway Contact Channel under Mechanical Construction +
###### Abstract  
The mechanical construction method for a subway contact channel has the advantages of a short construction period and high safety, and is more and more being applied in coastal soft-soil areas. In order to explore the suitability of this method in inland areas, a full-scale model test platform is used to simulate the shield-cutting construction process of the subway contact channel. The convergence deformation of the segments and the strain of the reinforcement and concrete are tested, so as to analyze the internal force and deformation law of the tunnel structure during cutting construction. The influence of the steel ring on the deformation of the subway contact channel is also studied. It is found that the segment convergence at the top is less than that at the waist position, and the convergence deformation of the waist is less than 30 mm; the internal force of the segment redistributes and the axial force mainly decreases during the cutting process; the stress state may change from compression to tension. The segment structure of the main tunnel, the supporting structure in the tunnel, and the stiffness of the steel-ring-lined composite pipe segment have little influence on the cutting force of the contact channel. The research results provide the corresponding technical indexes for the construction of a contact channel by the mechanical method, as well as a reference for the design and optimization of a steel-ring-lined composite pipe segment.  
contact channel; full-scale model test; mechanical construction; steel-ring lining 2023  
1310375
## 3 Sensing Per Crop
### Sensing Mango and Avocado Diseases
#### 3.1.1 Sensors and Algorithms

Table 3: Post-harvest operations where sensing is applied. fungicide sprays pear season to control flower anthracnose as compared to weekly spraying [149]. The Philippine model includes relative humidity in addition to wetness and temperature and was tested under field conditions [150]. Comparing both models present important differences in level of infection predicted from a given combination of temperature and wetness duration. High discrepancy indicates that weather-based forecasting systems for anthracnose should not be extrapolated from one region to another and the infection should be elucidated locally [84]. Although disease warning models have been developed, remote sensing is in its initial stage.
## 4 Discussion  
### The Reasons for the Spatio-Temporal Changes in Vegetation NPP  
The spatial distribution of vegetation NPP during 2000-2022 was roughly the same as that in 2000-2010 and 2011-2022, showing a decreasing trend from south to north and from east to west, which is consistent with the research results of [PERSON] et al. (2019). From the north to the south, the climate in southern China was hot and humid, and the precipitation was higher, which is conducive to vegetation growth. In the northern region, the climate type is mainly temperate continental. It was hot and rainy in summer and cold and dry in winter, and the vegetation growth environment was worse than that in the south, thus forming a spatial distribution pattern of high in the south and low in the north ([PERSON] et al., 2019). The western region of China was dominated by deserts and plateaus. The Taklimakan Desert and other regions had high temperatures all year round, scarce precipitation, and almost no vegetation coverage. Moreover, the Qinghai-Tibet plateau, with many glaciers and permafrost, had high altitude, low temperature, and scarce precipitation ([PERSON] et al., 2019). The vegetation type was dominated by alpine meadows, resulting in low levels of vegetation NPP. The eastern region was close to the Pacific and Indian Oceans. Due to the influence of ocean currents, the precipitation was richer than in the western region, and the vegetation types were more abundant. There were a small number of high-value areas in the northeast region and the southeast of the Qinghai-Tibet Plateau, which is consistent with the research results of [PERSON] et al. (2019). Specifically, Northeast China had rich forest resources, high-quality black soil, and organic matter, which is conducive to the accumulation of vegetation NPP. At the same time, in 1998, China implemented the \"Natural Forest Resource Protection Project\", which further helped to improve vegetation NPP, resulting in a small number of high-value NPP areas in Northeast China. The southeast of the Qinghai-Tibet Plateau, with more precipitation than other parts, was affected by a Pacific monsoon, and its vegetation types were diverse.  
In terms of time transfer from different grades, the transfer area from low to high accounts for a large proportion, and vegetation NPP showed an increasing trend, which is consistent with the research results obtained by [PERSON] et al. (2019) and [PERSON] et al. (2020). This may be related to China's implementation of returning farmland to forest and grassland as part of its protection policy for ecological areas. NPP is a key factor in determining the ecological process of regulating carbon sources within ecosystems. It plays an important role in global change and carbon balance, providing insights for scientific decision-making in ecological management and climate change mitigation.