esa-sceva/satcom-chunk-collection huggingface dataset:
# Compact 50 W All-Solid-State Picosecond Laser System at 1 kHz
###### Abstract
Nd:YAG, because of its large emission cross-section, long upper level lifetime, and good thermal and mechanical properties, is suitable for amplification at 1 kHz. In the paper, a compact structure 50 W and 50 ps at 1 kHz laser system based on Nd:YAG bulk crystal is reported. The thermal lens effect is very significant in the amplifier at 1 kHz, especially in the regenerative amplifier, and the thermal lens effect will cause the beam waist in the resonant cavity to become smaller and limit the output power of the regenerative amplifier. For this, a homemade high-power regenerative amplifier is used in this system; the regenerative cavity can achieve maximum output power of 6.5 W at pump power of 41.5 W. Compared with the amplification systems of the above-mentioned literature, this regenerative amplifier can achieve higher output power, thereby reducing the number of subsequent traveling-wave amplifications. The laser pulse output by the regenerative amplifier can be amplified to 50 W at 1 kHz after passing through an end-pumped traveling-wave amplifier and a side-pumped traveling-wave amplifier. Compared with the above-mentioned high-power laser systems, this laser system has a more compact structure.
###### Abstract  
Purpose: The purpose of this study was to estimate the effect of platelet-rich plasma (PRP) augmentation in microfractures of chordal lesions in elderly individuals. Methods: 29 patients with knee osteoarthritis were enrolled in the single-blinded randomized study. The study group consisted of 16 patients and 13 were in the control group. All surgeries were performed in the same manner. The PRP injection was made in a dry arthroscopy directly over the microfractures. The evaluation was performed preoperatively on the 6 th, 12 th, and 24 th week following the surgery. WOMAC and Lysholm questionnaires were utilized. Results: Microfractuation showed WOMAC improvement in the PRP group (\(p=0.0012\)) and in the control group (\(p=0.0042\)). No statistically significant differences between the two groups (\(p=0.698\)) have been found. Clinical improvement was noted in the first six weeks after which the effect lasted. In addition, Lysholm score showed no significant differences at the end of the follow-up between both groups (\(p=0.941\)). Conclusions: Arthroscopic microfracture improves motor function and reduces pain in patients over 50 years old. PRP augmentation of the procedure is safe, and can accelerate and prolong the therapeutic effect of treatment. Excellent effects of the procedure are observed in the first six weeks, after which the improvement lasts.  
Keywords: osteoarthritis; cartilage; platelet-rich plasma; cartilage regeneration; mechanical stimulation; microfract +
Footnote †: journal: Applied Sciences
# Application of Mastic Asphalt Waterproofing Layer in High-Speed Railway Track in Cold Regions
## 2 Material Design and Evaluation
### Laboratory Tests
#### 2.2.4 Low Temperature Bending Test  
Thermal cracking under low temperature is the main problem leading to the poor waterproof performance of conventional concrete waterproofing layers. Cracking of mastic asphalt is also critical to its overall waterproofing performance and durability. The three-point bending beam test was conducted to evaluate mastic asphalt cracking resistance at low temperature, with a test temperature of \(-10\)\({}^{\circ}\)C. As shown in Figure 2a, beam samples with the dimension of 250 mm \(\times\) 35 mm \(\times\) 30 mm were prepared and tested with the universal testing machine (UTM) produced by IPC Global (Melbourne, VIC, Australia). The test was displacement-controlled with a speed of 50 mm/min. During the test, the maximum load and the corresponding mid-span deflection were recorded, accordingly; the maximum tensile strain on the bottom of the beam could be calculated.
# A Data-Driven Deep Learning Framework for Prediction of Traffic Crashes at Road Intersections
## 5 Performance Evaluation
### Compared Methods  
We evaluate the performance of _RoadInTCP_ against four conventional methods and three deep learning models.  
**Logistic Regression (LR))**[32] is a classical linear classifier in machine learning. In this work, the liblinear optimization algorithm is employed.  
**Support Vector Machine (SVM)**[33] is a prominent classifier capable of handling linear or nonlinear separations within traditional machine learning methods. For our experiments, the kernel type is radial basis function (rbf), the kernel coefficient is set to'scale', the regularization parameter is set to 1.0, and the learning rate is set to 0.001.  
**Decision Tree (DT)**[34] represents a conventional machine learning classifier. Herein, the splitting criterion is entropy, and the maximum depth of the decision tree is set to 50.  
**Random Forest (RF)**[35] enhances the concept of Bagging by constructing an ensemble based on decision trees, further incorporating random feature selection during tree induction. In experiments, the forest consists of 10 decision trees, each with a maximum depth of 20, and the splitting criterion is entropy.  
**Multilayer Perceptron (MLP)**[36] is a feedforward neural network architecture. In experiments, the Rectified Linear Unit (ReLU) is utilized as the activation function with a learning rate set to 0.005.  
**Graph Convolutional Network (GCN)**[37] is leveraged for its capability to learn latent node feature representations by aggregating neighborhood information. For traffic crash prediction, a direct end-to-end two-layer GCN model is trained for comparative analysis.  
**Long Short-Term Memory (LSTM)**[38] is a temporal sequence prediction model capable of capturing temporal dependencies. In this work, according to previous research [39], a two-layer LSTM model is trained with consideration of traffic state characteristics from the past 12 h.
## 1 Introduction
Keeping in mind the constraints on time and processor capacity, we propose a low-complexity solution that uses the inherent structure in the data and a greedy heuristic to obtain an optimized configuration that works for both LOS and NLOS users [26; 28]. The terms used in the system modelling are listed in Table 2.  
This article delves into configuring an IRS for wireless communications, focusing on developing signal-processing algorithms tailored to optimize IRS settings based on user locations. Key contributions include innovative algorithms for estimating propagation channels and optimizing data rates. This work addresses challenges such as frequency-selective fading, discrete phase shifts, hardware imperfections, and limited measurement data, emphasizing the novel algorithms and methodologies created to overcome these obstacles. The research provides significant insights into critical aspects of wireless commun \begin{table}
\begin{tabular}{c l} \hline \(\mathbf{h_{d}}\) & BS-user (direct) channel \\ \(\mathbf{a_{n}}\) & The \(n\)-th IRS element’s BS-IRS channel \\ \(\mathbf{b_{n}}\) & The \(n\)-th IRS element’s IRS-user channel \\ \(\theta\) & IRS reflection coefficients \\ \(\mathbf{\phi}\) & Reflection coefficient of the IRS \\ \(\mathbf{\alpha_{n}}\) & Propagation Loss \\ \(\beta_{n}\) & Propagation Loss \\ \(\delta t\) & Dirac delta function \\ \(f_{c}\) & Carrier Frequency \\ \(Z\) & Received Signal \\ \(\mathbf{\overline{x}}\) & Fourier Transformation on signal \\ \(\lambda\) & Signal Wavelength \\ \(h_{\theta}\) & Overall impulse response of the channel \\ \(H_{d}\) & Frequency response of BS-User (direct) channel \\ \(V\) & Frequency response of the BS-IRS-User channel \\ \(\omega\) & Circularly Symmetric Gaussian Noise (CSGN) \\ \(\mathcal{N}_{\mathrm{C}}\) & F.T. of \(\mathbf{\omega}\) with variance \(\sigma^{2}\) \\ \hline \end{tabular}
\end{table} 
Table 2: Glossary of Terms and Notations used. Figure 1: Model of an IRS. nication, including channel modeling, statistical estimation, and optimization techniques. Utilizing MATLAB for the practical setup and synthetic data generation offered a realistic environment for testing these algorithms. The rest of this paper is organized as Section 2, the system model, followed by Section 3 with its channel estimation. At the same time, its subsection gives the gist for the noise estimation, followed by a subsection on finding parameters. Section 4 elaborates on rate optimization, where the algorithms developed are explained in its subsections: initialization and further optimization. Section 5 gives the elaborated results and outcomes of the algorithm and compares the results with the results available in the literature. Section 6, finally, concludes the entire work.
## 3 Data Acquisition and Processing
### Ground 3D Laser Scanning Point Cloud Data and Pre-Processing  
The Maptek I-site 8200 ER ground 3D laser scanner with IP65 protection class was used for scanning, and the main parameters are shown in Table 1. I horizontal angle and vertical angle were measured by a test accuracy of 7\({}^{\prime\prime}\)[16].  
The free station setting was adopted to ensure that the data from multiple stations were in the same coordinate system. In order to obtain a complete point cloud and ensure a 30% overlap of the scanned area, data acquisition could only be carried out by multiple stations. At the same time, GNSS RTK was used on-site to measure the 3D coordinates of the target points. In total, 7 stations were set-up to scan over 17.48 million point clouds, and the scanning area is shown in Figure 4a,b.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter Types** & **Parameter Indicators** \\ \hline Instrument leveling/(\({}^{\prime\prime}\)) & 20\({}^{\prime\prime}\) (Built-in compensator) \\ Compass/(\({}^{\circ}\)) & \(\pm\)1 \\ Maximum measuring range/(m) & 500 \\ Minimum measurement range/(m) & 1 \\ Distance accuracy/(mm) & 6 \\ Scanning Range/(m) & Vertical 270\({}^{\circ}\), horizontal 360\({}^{\circ}\) \\ Angular Resolution/(\({}^{\circ}\)) & 0.2-0.025 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Parameters of Maptek I-site 8200 ER ground 3D laser scanner.  
Figure 3: Flow chart of point cloud data acquisition.  
In the data acquisition process, as the coordinate system of each survey site cloud data point is independent of each other, and the acquisition process will inevitably generate noise points, the point cloud must be pre-processed before processing and analysis. By using the supporting software Maptek I-Site Studio to perform stitching, alignment, denoising, and other operations, the point cloud data of the study area were obtained, as shown in Figure 4c,d. The 3D laser scanning technology had a high measurement accuracy and high speed, but the scanning range was limited in the vertical direction, and some point clouds had voids when facing complex terrain conditions such as high and steep cliffs (Figure 5).
## 1 Introduction  
The dorsal aspect of the distal tibia, which is the bony fixation of the posterior inferior tibiofibrular ligament (PITFL), is commonly referred to as the posterior malleolus (PM). Frequent injuries of the posterior syndesmosis complex occur with an intact PITFL and a fracture of the PM [1]. On the one hand, the bony avulsion of the PITFL leads to the loss of one of the main stabilizers of the syndesmosis; on the other hand, the fragment can affect the articular surface of the upper ankle joint. This leads to damage of the articular cartilage and most likely plays an important role in the pathogenesis of long-term complications such as chronic pain and post-traumatic osteoarthritis [1, 2].  
It is well accepted that PM should be fixed if the fragment includes at least 25% or 33% of the tibotalar articular surface [1,3]. However, no data exists for decisions based on percent joint surface involvement [4]. In their systematic review, [PERSON] et al. made the following recommendations for the indication of surgical treatment of PM fractures [5]:  
* The original size and congruence of the articular surface of the tibial pilon and, thus, the posterior stability of the ankle should be restored;
* The integrity of the posterior tibofibrular ligament and, thus, the stabilizing function of the upper ankle joint should be restored;
* The integrity of the fibular notch should be restored to facilitate the reduction of the distal fibula, especially in high Weber type C fibular fractures, including Maisonneuve fractures.  
The reduction can be performed indirectly using ligamentotaxis and minimal invasive fixation from the anterior in the case of easily reducible fragments or directly from the posterior in case of insufficient reducibility [6]. There is no clear recommendation regarding which approach and which osteosynthesis (OS) technique should be preferred [7, 8, 9].  
[PERSON] et al. referred the direct reduction and p.a. OS as biomechanically more stable than indirect reduction and a.p. screw fixation [5]. However, biomechanical results comparing a.p. and p.a. screw OS are not yet available. The purpose of the biomechanical study presented here was to clarify whether the direction of screw OS of a PM fragment has a relevant impact on the primary stability under torsional loading.  
In contrast to [PERSON] et al. [5], it was hypothesized that there is no biomechanical difference in primary stability between screw osteosynthesis of the PM with respect to the direction of screw insertion (p.a. versus a.p.) for stabilization of a fracture of a large PM fragment (type IV according to [PERSON] and Rammelt [9]).
# A Comprehensive Worst Case Bounds Analysis of IEEE 802.15.7
## 3 Technical Overview
### MAC Sublayer
#### 3.2.2 Dimming Mitigation  
Dimming can be defined as controlling the brightness of the light source in accordance with the users requirement. Dimming can be done by several methods such as adding compensation symbols, controlling pulse width, and controlling the amplitude of the signal. Compensation symbols are similar to an idle frame that is sent along the data frames, which will reduce the level of brightness. The other techniques include adjusting the level of brightness by a certain percentage regularly between every frame to mitigate the dimming of the light source.
# A Study on the Impact of Low-Frequency Random Loading and Unloading on Silo Structures
## 4 Discussion  
Through on-site in situ monitoring of the stress conditions of the silo combined with numerical simulation analysis, this article concludes that the cause of silo wall damage is the randomness of the stacking and unloading of materials, which exerts uneven horizontal lateral pressure on the same horizontal position of the silo wall, resulting in large bending moments and torque on the wall, leading to cracks in the silo wall. Additionally, uneven loads are generated vertically along the silo wall, causing fatigue damage to the silo under the combined effect of tension and bending cycles.  
Addressing these issues, this article first proposes a solution to reduce the loading frequency by slowing down the speed of feeding and discharging materials in the process, thereby extending the service life of the silo. Additionally, this article presents an improved scheme to alter the silo's loading and unloading mode, which involves designing silos with either six or eight discharge ports.  
Due to limitations in time and personal capabilities, many areas of improvement remain in this research. Future research can further explore the following aspects:  
1. The calculations in this paper did not take into account the bond-slip effect between steel and concrete, as well as the stress redistribution during the fatigue degradation process of the silo. This leads to discrepancies between the finite element simulation results presented in this paper and the actual situation. Therefore, further research is needed on the simulation calculation of the fatigue life of the silo.
2. This article proposes enhancing the durability of silos by reducing the feeding and discharging speed or changing the loading and unloading mode. However, specific research on the optimal feeding and discharging speed and optimal discharge port silo has not been conducted. This can be further explored in the future.
3. The fatigue life of a silo is influenced by many factors. This article only explores the fatigue life of silos under dynamic loads. In the future, more dimensions can be analyzed, such as corrosion issues, concrete strength grades, silo wall thickness, and load stress amplitude, to more comprehensively elucidate the specific effects of these factors on the fatigue life of silos.
## 3 Simulation Results
To mitigate this, an algorithm is implemented to detect and correct phase jumps by referencing the previous symbol, resulting in a more realistic representation of the residual phase noise. Figure 17b shows the quantile-quantile plot that compares residual noise quantiles against the theoretical quantiles of a normal distribution, using the Cosine-RLOWESS interpolator. A linear pattern in this plot suggests that the residual noise follows a normal distribution. However, at higher noise variance, observable at an SNR of \(25\,\mathrm{dB}\), with a linewidth of \(\Delta\
u=Figure 5:5\), a symbol rate of \(R_{s}=Figure 5:6\), and a modulation order of 64 QAM, the plot's extremities begin to diverge. This divergence indicates variability in phase noise differences near the boundaries, particularly around a value of \(\pm 0.15\). This value can fluctuate on the basis of the overall phase noise variance, and in more degraded environments the quantiles may exhibit extreme peaks at the edges.
# Review of Magnetoelectric Effects on Coaxial Fibers of Ferrites and Ferroelectrics
## 7 Follow-Up Research  
Future efforts on coaxial fibers of ferrites and ferroelectrics need to focus on studies aimed at the following factors: (i) ME measurements to date on single fibers are rather indirect, utilizing PFM under an applied H or MFM under E in order to come up with an estimate of the variation in ferroic order parameters and ME coefficients. Available data obtained from SPM measurements of MEVC and ME susceptibility on isolated fibers of CFO-BTO and CFO-PZT indicate very strong coupling with values comparable to or exceeding the theoretical estimates. Although direct measurements of MEVC involving the application of AC and DC magnetic fields to a single fiber and measuring the resulting induced voltage may be challenging, such measurements are essential for an understanding of ME coupling in coaxial fibers. (ii) Studies on fibers with Zn-substituted CFO are yet to be reported. Even though CFO has large magnetostriction, the piezomagnetic coupling coefficient q is rather small. One could enhance q-values in CFO with Zn-substitution. Thus, fibers of CZFO-PZT/BTO are expected to show strong ME coupling. (iii) The MEVC very much depends on the volume fraction of the ferrites and ferroelectrics in the fibers. There is a wide distribution in the core radius and the shell thickness in fibers prepared by electrospinningning. Studies relating the fiber dimensions to ME coupling are essential. (iv) Modeling of H-induced ferroelectric polarization is also essential to understand the \"giant ME coupling\" inferred from measurements on fibers discs. (v) Al-substituted M-type Sr and Ba ferrites have much higher q and magneto-crystalline anisotropy fields than BaM or SrM and are good candidate materials to achieve strong zero-bias ME coupling in fibers with ferroelectrics. (vi) In addition to the fiber composites discussed here, there are several Y- and W-type hexaferrites with high magnetostriction that are good candidates for use in fiber ME composites. (vii) Experiments aimed at enhancing ME coupling on a collection of fibers are essential, since any applications related to sensors or energy harvesting will require fiber assembly.
## 2 Related Work
### Cooperative Based Protocol  
In this paper, we deal with asymmetric links. Moreover, we exploit the cooperative communication in asymmetric links. There are many cooperative-based protocols in wireless sensor networks. Among the various types of cooperative based protocol, some of them consider asynchronous communication. In this work, we also consider the asynchronous mechanism, thus, in this subsection, we discuss some prominent asynchronous cooperative based communication mechanisms.  
[PERSON] et al. proposed CL-MAC [46], which uses cooperative communication in low power sensor networks. In CL-MAC, a piece of a shorter preamble packet is sent to each of the sender's relay and destination nodes. This small preamble notifies all relays and receivers to awaken at a universal rendezvous (RDV) point. The main disadvantage of CL-MAC is the need for time synchronization, and the preamble, even though it is small, creates additional overhead. ARQCRI [47] works over CL-MAC and tries to disregard time synchronization. When receivers send beacons, the sender transmits a copy message to notify the receiver to wait a few moments for the selection of the relay. When the relay is selected, then the sender transmits the data to the receiver and the relay. This method successfully ignores time synchronization, but is unable to handle the situation in which the sender is unable to send the copy message. CPS-MAC [48] uses a series of short preambles to seek the attention of the receiver and all the neighbor nodes, which creates extra overhead like in CL-MAC. It offers a tree-based mechanism with one sibling, but, if there is more than one sibling, then there may be a possibility to relay data to more than one neighbor, which may create a collision. There is no mechanism for effective relay selection. In RIC-MAC [49], there is no need for an extra preamble to wake up the receiver and neighbor nodes at a common RDV Point, as it uses two different wake-up beacons for the receiver and relay. The main disadvantage is that it creates huge idle listening. Moreover, similar to CPS-MAC and ARQ-CRI, it does not offer effective relay selection. Table 2 shows the comparative analysis of some prominent asynchronous cooperative MACs for WSNs. Upon finding their inappropriateness, this paper attempts to build a cooperative communication based protocol that not only avoids the asymmetric link situation, but also selects relay nodes efficiently without the extra control message exchange or other clock synchronization problems. Thus, in short, a protocol is designed to avoid the link asymmetry situation.