esa-sceva/satcom-chunk-collection huggingface dataset:
# Dimensional Reduction-Based Moment Model for Probabilistic Slope Stability Analysis
## 5 Applications
### Slope with Multiple Soil Layers  
In this section, a classical complex slope was utilized to verify and illustrate the proposed method [23]. The slope consists of three soil layers. Table 9 lists the soil property and their uncertainty for each layer. Similar to Section 5.2, a numerical method was used to evaluate slope stability based on the strength reduction method. The numerical model was built first, and the geometry and numerical mesh are shown in Figure 12.  
Figure 11: The comparison of reliability analysis using the proposed method and RSM.  
Figure 10: The probability distribution of safety factor using MDRM based reliability analysis.  
In order to verify the proposed method, the traditional RSM was utilized to evaluate the slope reliability, and the reliability index is 2.97. The proposed method was also used to determine the reliability index. It is 2.91 and is close to the reliability index obtained by RSM. The result is in excellent agreement with the traditional response surface method. The relative error of the reliability index is less than 2%. The comparisons of the reliability index are shown in Figure 13. The proposed method can be applied to the practical slope, which includes multiple soil layers and has a complex soil layer.
# Simplified Derivative-Based Carrierless PPM Using VCO and Monostable Multivibrator
###### Abstract  
This study proposes a derivative-based, carrierless pulse position modulation (PPM) scheme utilizing a voltage-controlled oscillator (VCO) and a monostable multivibrator. In contrast to conventional PPM systems that rely on reference carriers or complex demodulation methods, the proposed architecture simplifies signal generation by directly modulating the time derivative of the message signal. The modulated signal, when processed through standard analog demodulators, inherently yields the derivative of the original message. This behavior is first established through theoretical derivations and then confirmed by simulations and circuit-level experiments. The proposed method includes a differentiator feeding into a VCO, followed by a monostable multivibrator to generate a carrierless PPM waveform. Experimental validation confirms that, under all tested demodulation approaches--integrator-based, PLL-based, and quasi-FM--the recovered output aligns with the differentiated message signal. The integration of this output to retrieve the original message was not performed to maintain focus on verifying the modulation principle. Additionally, the study aimed to ensure the consistency of derivative recovery. Signal-to-noise ratio (SNR) expressions for each demodulator type are presented and discussed in the context of their relevance to the proposed system. Limitations and directions for further study are also identified.  
signal modulation; rectangular PPM; carrierless PPM; frequency modulation; phase-locked loop; voltage-controlled oscillator Article
## 4 FWA Design Considerations, Challenges, and Solutions
### Robust Ecosystem  
The 5G FWA realization also depends, in part, on the existence of a robust ecosystem where different stakeholders such as CPE vendors, chipset vendors, and network vendors are actively participating. This will give the operators the privilege of multiple vendors' operations. Consequently, this will open up a competitive market in which there will be innovative products that can be cost-effectively obtained. Remarkably, the global ecosystem of different devices and infrastructures can be well facilitated through the efforts of standards organizations. For instance, when standards-based equipment is deployed in the 5G FWA, there is a high potential for leveraging the related network elements for a fully mobile 5G deployment. In essence, this will facilitate the system's ability to support more new connections and offer additional bandwidth economically, promptly, and flexibly over time, to support the perpetual changing system requirements. Therefore, 5G FWA system scalability will be highly challenging if this is not in place [6].  
In addition, it has been observed that the global operator community has to converge to a technological standard to make the network devices and their deployment cost-effective. Accordingly, implementation of and compatibility with 3 GPP specified radio access scheme will help in encouraging scalability and interoperability in full potential. Moreover, according to AT&T, one of the main high-level fundamentals for effective deployment of 5G FWA is the 3 GPP release 15 and 16 standards completion [5].
# Design and Analysis on Decoupling Techniques for MIMO Wireless Systems in 5G Applications
###### Abstract  
Multiple-input multiple-output (MIMO) wireless system is a hot research topic in 5 th generation mobile communication technology (5G), which can increase the channel capacity of the antenna system to meet new communication demands without changing the bandwidth and transmission power. However, adding the number of antenna elements in a limited space size can lead to mutual coupling effects and impair the communication quality. Therefore, it is significant to design a compact MIMO wireless system using decoupling techniques. Several studies on the reduction of mutual coupling effects have been proposed. However, a concrete overview of the features and resemblances of these decoupling techniques is lacking. In this review, we provide a brief description of the research background on the mutual coupling effect of MIMO. Then, various decoupling techniques worthy of reference are classified and outlined. We further summarize the additional impacts due to the existence of different decoupling structures, and the possible usability and defects of these techniques are revealed clearly in this paper. Finally, a future outlook on the development direction of decoupling techniques for MIMO wireless systems is also concluded and discussed.  
5G mobile communications; MIMO wireless systems; decoupling techniques +
Footnote †: journal: Applied Physics Letters
# Implementation of an Attribute-Based Encryption Scheme Based on SM9
## 2 Prerequisites and Overview
The input of the Encrypt function includes a generic access structure \(A\) and the message that is to be encrypted. Users holding the private key corresponding to the attributes satisfying the access structure \(A\) through the Decrypt function can only successfully decrypt the output of the Encrypt function. Sm9 ABEHybridEngine implements the hybrid ABE scheme that is proposed in Section 5, which optimizes the ciphertext size of the ABE scheme that is presented in Section 4.
## 5 Applications of the Proposed Solutions
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Interface** & **BB** & \
\begin{tabular}{c} **Optical** \\ **Channel BW** \\ \end{tabular} & **OWS** &
\begin{tabular}{c} **Number of** \\ **Optical Channels** \\ \end{tabular} & **Format/Split** \\ \hline - & (MHz) & (GHz) & (nm) & - & - \\ \hline BBoF & 400 & 1.5625 & 0.1462 & 10 & 10 & A-RoF/Option 8 \\ eCPRI & 400 & 50 & 2.8021 & 6 & 10 & D-RoF/Option 6 \\ BBoF & 400 & 12.5 & 1.1689 & 10 & 10 & A-RoF/Option 8 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Calculated comparative parameters for detailed scenario No. 2 to switch from D-RoF to A-RoF format (the optical channel count-down is starting from wavelength equal to 1675 nm)—Figures 10 and 12 (128-element antenna-array and 4-sector unit). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Interface** & **BB** & \
\begin{tabular}{c} **Optical** \\ **Channel BW** \\ \end{tabular} & **OWS** &
\begin{tabular}{c} **Number of** \\ **Optical Channels** \\ \end{tabular} & **Layers** & **Format/Split** \\ \hline - & (MHz) & (GHz) & (nm) & - & - \\ \hline BBoF & 400 & 1.5625 & 0.1462 & 10 & 10 & A-RoF/Option 8 \\ eCPRI & 400 & 50 & 2.8021 & 6 & 10 & D-RoF/Option 6 \\ BBoF & 400 & 12.5 & 1.1689 & 10 & 10 & A-RoF/Option 8 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Calculated comparative parameters for detailed scenario No. 3 to switch from D-RoF to A-RoF format (the optical channel count-down is starting from wavelength equal to 1675 nm)—Figures 9 and 12 (32-element antenna-array and 4-sector unit). For the calculations related to the conversion from the number of channels realizing communication in the optical fronthaul/midhaul link/path to the OWB, a simplified version of the Formula (7) was applied. The proposed entirely optical network in this study may also have other applications. If the gNB-DU terminating devices are modified accordingly, then we can use them in other work areas. Light fidelity (Li-Fi) networks can be such an example. If the optical stream from the photonic switch (Figure 3a) is guided directly to the light emitter, then it will be possible to implement the Li-Fi network. Before radiating, however, the signal should be properly amplified and scattered, because in the optical path of the xWDM-based network we cannot use too much optical power. An additional limitation is that the operating ranges of radiators that are in general use are not adapted to the optical bands used in fiber optic communication. If the Li-Fi network needs to be moved to the visible light communication (VLC) systems, basically all photonic elements of the proposed network will be subject to changes. Only the all-optical network architecture will remain unchanged. In the case of small-scale VLC networks, it is possible to use polymer optical fibers (POFs) and PXC/ROADM/OM/OD operating in the visible light range [52].
# Re-Optimized Design for the ADR-Based Dual-Loop Controller of 100 m Class Aperture Radio Telescope
## 1 Introduction
[PERSON] [24] employed the extended state observer (ESO) of the ADRC to attenuate the adverse effect of the uncertainties of the GBT. [PERSON] et al. [25] applied ADRC to the position-loop of the Leighton Chajnantor telescope to strengthen the wind-disturbance rejection ability of the antenna servo system. The order of ADRC can be chosen according to the controlled plant model's relative order, and thus, may be much less than the model's order, mainly due to the ADRC's different understanding of the controlled plant model. The scenario in which ADRC is used in this paper is a typical example. The contributions of this paper are as follows:  
(1) A single-input, multiple-motor-driven, multi-output (SIMO) motor-load model of an antenna servo system is developed. The antenna load that causes shaft-load speed fluctuation is considered a disturbance term for the motor-gearbox velocity control. (2) A linear ADR-based controller coupled with disturbance-rate compensation (DLADRC) is designed for the velocity-loop, which improves the initial dynamic response and enhances the anti-disturbance performance of the complex antenna system. A first-order low-pass filter and a notch filter are further introduced to improve the speed-tracking characteristics of the off-velocity-loop antenna's structure. The position-loop employs a proportional controller in the base of the DLADRC-based velocity controller, simplifying the parameter-tuning of the position controller. (3) The proposed control scheme is characterized by less dependence on the controlled plant information, a simple controller structure, easy parameter tuning, good command tracking, disturbance rejection, and high robustness against parametric perturbations. In the rest of this paper, we introduce our studies on multiple-motor-driven antenna modeling in Section 2 and controller design in Section 3. Simulation and analysis of the control scheme are illustrated in Section 4, and finally, a summary is given.
## Appendix A Measurement Methodology (Development of Measurement Methodology)
### Measurement Methodology Using a Multirotor Rotary-Wing Aircraft  
Due to the short flight time and speed of rotary-wing aircraft, the measurement of antenna radiation is divided into two stages:  
* Determination of the radiation maximum along the vertical axis (Figure 11a). In this stage, the aircraft ascends vertically (at an approximate measurement distance from the antenna being measured), and radiation strength measurements are taken. This process identifies the height at which the antenna under investigation radiates the most, i.e., the altitude at which the circular flight will be conducted in the next stage.
* After determining the antenna's radiation maximum along the vertical axis, the second flight involves measuring the antenna's radiation on the horizontal plane (Figure 11b). In this stage, the aircraft flies in a circle at the determined altitude and radius (typically 200 m) around the antenna being measured, collecting radiation strength data. The flight speed is usually limited by the aircraft's capabilities and weather conditions, typically ranging from 5 to 7 m/s.  
After completing the flight around the tower, a circular diagram of the antenna's strength is generated in the developed software (Figure 14c), which can then be compared with the theoretical antenna pattern.
## 4 Security Threats
### Implementation
#### 4.4.2 Transmission Power Thresholds Violation  
A large number of approaches found in the literature carry out the required spectrum sharing process in the dimension of space [58]. To be more specific, in case a network has fewer channels available than the number of nodes requesting their usage, a common approach is to adjust the transmission power of the latter in a clever way so as to increase the reuse factor and the network's capacity and eliminate the interference caused due to simultaneous packet transmissions over the same channel in the same area. The first step in this direction is to divide the nodes of a network into carefully selected sets. Although each such set must be assigned with a different channel, this requirement is not always sufficient to mitigate the interference problems which can arise. So, a complementary technique often used is that of adjusting the transmission power of each network node so that no two simultaneous transmissions by neighboring nodes can interfere with each other.  
The obvious strategy for nodes, without considering possible reprisals and long term results, is to transmit at the highest energy level supported by their hardware (if energy and life-time considerations for battery powered devices are not taken into account). In this way, each node will attempt to overcome any potential noise-related packet loss, as well as achieve the highest possible QoS level. But, if all (or many, or other strategically placed) nodes decide to behave in a similar way, the consequences for the underlying network will be destructive. In the ideal case, each node should continue lowering its transmission power until the lower bound of his satisfaction level is reached, and sometimes even lower, in order to achieve fairness and maximize the social welfare. However, since most of the time there is no direct incentive for a node to behave in such a possibly unfavorable way to its short-term interests, approaches relying on such expected, suggested, or dictated power adjustment techniques may fail to fulfill their aims.  
Network nodes may have strong incentives to violate the transmission power-related rules, letting numerous irregular conditions to arise. A node decreasing his transmission power may probably suffer from increased packet loss rates and insufficient QoS, compared to when he transmits at full power. A greedy or conservative node may thus choose not to abide by such power-related rules for gaining extra profits, or avoid operating in unfavorable conditions, respectively. Such adversarial behavior will unavoidably result in increased interference levels inside a DSA network, while significant QoS degradation will also be suffered by other conformant nodes. In a similar way, a malicious node may purposefully push its transmission power to its limits causing strong disturbance in such a network, decreasing his competitors' profits or even affecting Primary Users' transmissions. Such an attack may also be realized to decrease the \"reputation\" of special channels available, and especially those which are considered highly profitable by his competitors [49].
## 3 Results and Discussion  
### Swelling Degree and Degradation Rate  
Hydrogel swelling ability is crucial for the penetration of nutrients and for the transport of metabolic products, thus promoting cell viability and proliferation within the hydrogel [30]. Moreover, when developing a hydrogel as a bioink, its swelling behavior needs to be evaluated and optimized to preserve the shape fidelity of the printed structures once immersed in culture medium [16]. Figure 3a displays the average swelling degree of the SA-G hydrogel samples. Within the first hour, the average degree of swelling increased to approximately 55%. Then, the hydrogel samples continued swelling at a slower rate with an average rise of 20% until the sixth hour, when they reached the swelling plateau. The maximum swelling degree value was 80%, on average. Such a value allows for the uptake and transport of nutrients dissolved in the cell culture medium, thus favoring cell viability and proliferation, while retaining shape fidelity of the printed constructs. Indeed, based on the findings of [PERSON] et al., bioinks characterized by a swelling degree of nearly 100% did not show significant spreading of filaments and pores in the printed constructs [31].  
As for the degradation rate, the material should progressively degrade to allow cells to proliferate and deposit new extracellular matrix while preserving the initial structure of the printed constructs [32]. The SA-G hydrogel samples exhibited a constant weight decrease over 21 days (Figure 3b). On day 21, the average weight decrease was 16%, although few samples were completely degraded.
## 3 Rigid Model Pressure Measurement Test
### Data Processing Method  
The wind pressure field is usually analyzed by using the wind pressure coefficient. Its advantage is that the coefficient is dimensionless, and the wind pressure coefficient of the corresponding point on the actual structure and the test model is the same, which brings convenience to the analysis. The research of this paper aims to analyze the effectiveness and accuracy of POD technology in the reconstruction of wind pressure field of large-span folded-plate roof. The wind pressure coefficient is used as a very effective tool parameter. According to the pressure time history of each measuring point obtained by the test, the mean wind pressure coefficient of the corresponding measuring point can be obtained:  
\[C_{\overline{P_{i}}}=\frac{\overline{P_{i}}-\overline{P_{\infty}}}{\overline {P_{0}}-\overline{P_{\infty}}} \tag{13}\]  
Figure 4: Schematic diagram of the test wind direction angle.  
where \(C_{\overline{P_{i}}}\) is the mean wind pressure coefficient of the \(i\)-th measuring point; \(\overline{P_{i}}\) is the mean pressure value of the \(i\)-th measuring point; \(\overline{P_{0}}\) and \(\overline{P_{\infty}}\) are the mean total pressure and static pressure at the reference height at infinity, respectively.
## 2 Methods
### Polar Code
#### 2.2.1 Encoding with Polar Codes  
The encoding process of Polar Codes is founded on a specific construction of a generator matrix which exploits the recursive nature of code construction. The key operation in Polar Code encoding is the application of a transformation matrix, typically denoted as \(G\), to the input vector \(u\) of length \(N\). The matrix \(G\) is defined recursively by  
\[G=F^{\otimes n} \tag{1}\]  
where \(F\) is the basic transformation matrix given by  
\[F=\begin{bmatrix}1&0\\ 1&1\end{bmatrix} \tag{2}\]  
and \(n\) is such that \(N=2^{n}\). The \(\otimes n\) denotes the \(n_{th}\) Kronecker power of \(F\), representing the recursive construction of the code.  
The vector \(u\) contains both data and frozen bits, with frozen bits set at known positions (often zero) and known to both the encoder and decoder, reducing the transmission's redundancy. The encoded vector \(x\) is computed as  
\[x=u\cdot G \tag{3}\]  
This operation linearly transforms the input vector \(u\) using the matrix \(G\), resulting in the coded vector \(x\) ready for transmission over the channel.
# A Discrete Hidden Markov Model for SMS Spam Detection
## 3 The Discrete HMM for SMS Spam Detection
### The Workflow of the Discrete HMM for SMS Spam Detection
#### 3.7.2 SMS Classification  
Given the trained HMM and observation sequence, the classification process involved finding out the optimal hidden state sequence and making a prediction of the SMS property based on the majority role. The SMS classification workflow is shown in Figure 6.  
Step 1: Like the preprocess in the training workflow, the SMS dataset for classification is also first split or segmented into word sequences to keep their original word order. Then, stop words are removed from the sequence and the observation sequence is formed.  
Step 2: Use the Viterbi decoding algorithm to find the optimal hidden state sequence for each SMS.  
Step 3: Predict the SMS property based on the majority role.  
Figure 5: Training workflow.  
Figure 6: Short messaging service (SMS) classification workflow.
## 2 Facility and Methods  
### Experimental Device and Operation Process  
As shown in Figure 1, circulating cooling water was drawn out of the water collecting tank by placing a water circulation pump into the circulation pipe and was then processed by the AEFT device to enter the counter flow heat exchanger. The circulating cooling water was sprayed into the cooling tower to dissipate heat and collected again in the water collecting tank to form a loop. The circulating water flow rate was set to 1000 L/h. Each set of experiments lasted 12 h, and the water indicator was measured every 2 h.  
A heat exchanger is a double-layered casing structure. The circulating cooling water flows through the internal copper pipe, and the heated water flows outside the copper pipe. The inner wall of the copper tube must be smooth because the surface roughness increases the nucleation site and the fouling resistance [22]. The inner diameter and thickness of the copper tube were 22.5 and 2.5 mm, respectively. Calcium carbonate scale was formed and deposited on the inner surface of the copper tube. PT100-type temperature sensor was installed in the inlet and outlet of the heated water and circulating cooling water, respectively. A computer recorded the temperature of each inlet and outlet every 10 min. In the experiment, the temperature of the circulating cooling water was controlled at 32 \({}^{\circ}\)C \(\pm\) 2 \({}^{\circ}\)C, and that of the heating water was controlled at 90 \({}^{\circ}\)C \(\pm\) 4 \({}^{\circ}\)C.  
As the experiment progressed, the amount of calcium ions and carbonate ions decreased due to the formation and precipitation of calcium carbonate. Hence, CaCl\({}_{2}\) and NaHCO\({}_{3}\) were supplemented at flow rates of 1.2 and 1.5 mmol/L-h, respectively, to maintain the calcium ion concentration and the alkalinity of the circulating cooling water.