esa-sceva/satcom-chunk-collection huggingface dataset:
# Performance Analysis of NR-DCSK Based Copper Cable Model for G.fast Communication
## 1 Introduction
When modeling the DSL network for G.fast technology, four network classes were established-urban, suburban, dense rural and sparse rural networks [19]. According to twisted pair connections in Austria, 99.9% of urban, 99.6% of suburban, 64.4% of densely populated rural and 70.1% of sparsely populated rural customers were remote through G.fast's deployment-Nodes covered. Using Distribution Points (DPs), rural coverage was improved and increased to 98.7% and 97.2% respectively. G.fast performance was found to be significantly affected by cable types. The performance simulations of the 106a and 212a G.fast profiles showed that bit-rates were highest in urban areas and lowest in suburban areas. On the other hand, a simple chaos communication system was initially developed [20] as Differential Chaos Shift Keying (DCSK) to improve the performance of the communication system. DCSK ensures continuous transitions in transmitted signals, avoids the carrier synchronization of chaos shift keying (CSK) using noncoherent detection, and has wideband characteristics. Therefore, in the last two decades, DCSK modulation has been further developed by researchers into a robust modulation scheme for communication over various channels. Modifications such as [21; 22; 23; 24; 25; 26] quadrature chaos shift keying, code-shifted DCSK, generalized code-shifted DCSK, high-efficiency DCSK and short reference DCSK are implemented to improve the transmission rate and save energy. In addition, noise reduction (NR) techniques have been implemented [27; 28] to mitigate the effects of noise on the received signal. To the best of our knowledge, the researchers have not covered DCSK modulation with copper cable channels in the presence of impulsive noise. Power line communication systems [29] and G.fast with copper cables are vulnerable to the impacts of multipath channels and impulsive noise. However, the DCSK system has shown strong performance in these types of environment. Therefore, when used in copper cable channels, we expect the DCSK system to produce positive outcomes. This promotes the adaptation of this system to G.fast communication and opens new horizons for the future of G.fast transmission. The contribution of this work can be summarized as follows:  
1. We propose a noise reduction-DCSK (NR-DCSK) modulation to improve the security and the bit error rate (BER) of the digital communication system over the copper wire communication channel with the existence of the Middleton class A impulsive noise model. The NR technique in [27] is utilized to improve the system performance. 2. We derive the theoretical BER formula for the proposed model and compare it with the BER simulation results. This work is organized as follows. In Section 2, the system model for the copper cable communication system is presented, Section 3 demonstrates the performance analysis and deriving the theoretical BER of the proposed system, Section 5 shows the simulation result and the discussion of these results, and the conclusion is drawn in Section 6.
## 4 Results and Interpretation  
### AFT Age Data  
The central ages, mean track lengths, and mean Dpars of the apatite fission track are listed in Table 2. The seven samples (LS-82, LS-86, LS-94, LS-95, LS-96, LS-97, and LS-98) have been dated with the AFT methods. The mean track lengths vary from 11.8 \(\pm\) 1.8 \(\upmu\)m to 12.8 \(\pm\) 1.8 \(\upmu\)m, and the central ages of the AFT are between 52 and 118 Ma. The standard deviation (SD) ranges between 1.5 and 1.8 \(\upmu\)m for the AFT track lengths. The mean Dpar values of the AFT range from 1.25 to 1.49 \(\upmu\)m.  
All AFT ages in this paper are younger than their strata ages, indicating that all single-grain ages have been reset after deposition (Figure 4A). Most of the samples experienced multiple annealing processes because the \(\chi^{2}\) value is <5%, except sample LS-82, for which the \(\chi^{2}\) value of apatite is >5%. Apatite fission track age was decomposed by using Radial Plotter [32] with the automatic mixture model (Figure 5), and then divided into 4 age groups (Figures 4A and 5): 147 Ma, 120-109 Ma, 92-77 Ma, and 65-50 Ma. According to [PERSON]'s collection and conclusion [33], we could divide the apatite tracks into three types with different dispersions of the track lengths and standard deviations: (i) the freshly induced tracks in all apatites with a narrow and symmetrical length distribution of 16.3 \(\upmu\)m track length and 0.9 \(\upmu\)m SD; (ii) the track lengths in apatite from undisturbed 'volcanic' rocks with track lengths ranging from 14 to 16 \(\upmu\)m and SD ranging from 0.7 to 1.3 \(\upmu\)m; and (iii) the track lengths in apatite from crystalline basement rocks with track lengths ranging from 12.2 to 13.9 \(\upmu\)m and SD ranging from 1 to 1.6 \(\upmu\)m. For type (ii), if the mean length is <13 \(\upmu\)m and SD > 2 \(\upmu\)m, a bimodal distribution will exist. Therefore, the tracks in this study belong to type (iii) with <14 \(\upmu\)m track length and 1.8-1 \(\upmu\)m SD, indicating that the southern HTB has crystalline basement rocks.
## 4 Results
### Potential Landslides Validation  
The potential landslide sites identified through the InSAR analysis in this study were primarily verified against field investigation, and some inaccessible ridge-top sites were validated via optical image interpretation according to the procedure described in [PERSON] et al. [62] and topographic map analysis [64]. The UAV images and optical images in Figure 11 clearly show examples of the cracks and scars induced by slope sliding in the study area that were used to validate potential landslides. In particular, the Chunchangba site, located at TS6 (see Figure 6 for its location), was selected as a typical case to further highlight the validation. The SAR results show that the average annual deformation  
Figure 7: Ground deformation velocity along the LOS direction obtained from the descending orbit SAR images.  
velocity around Chunchangba site reached \(-28.85\) mm/year in the ascending data set and \(-20.23\) mm/year in the descending data set, indicating significant ground motion in the slope. The UAV photogrammetry showed the existence of large deformation as well as cracks and rockfalls on the slope (Figure 12). These results suggest that the InSAR results are accurate and the Chunchangba area is confirmed as an active landslide site. In summary, a total of 81 potential landslide sites were confirmed, accounting for 81.82% of the entire clustered results. The remaining sites were eliminated because they are mostly related to the activities of glacial till or superficial material movement (Figure 11d).  
Figure 8: Time series of displacement at sample monitoring points (see Figures 6 and 7 for their locations) obtained from the ascending (**a**) and descending (**b**) data sets. Note: the initial displacement of each monitoring point is assumed to be 0 mm.  
Figure 9: Results of hot spot analysis using the (**a**) ascending and (**b**) descending data sets.  
Figure 11: Deformation evidence in the study area from UAV images (**a**,**b**) and optical images (**c**,**d**).  
Figure 10: Potential landslide sites obtained through cluster and buffer analyses.
# Variable Rate Point Cloud Attribute Compression with Non-Local Attention Optimization
## 3 Point Cloud Attribute Variational Autoencoder
### Variable Rate Autoencoder Network  
Variable rate is achieved by modulating the latent features of different layers in the encoder and the decoder, which means multiplying the feature map and the modulating/demodulating vector in a channel-wise production manner. Figure 4 shows the form of two-layer modulation, and in practice, the output of each convolution layer or attention module is modulated. Given a feature map \(X_{i}\) of channel \(i\) in the encoder, and the output map \(X_{i}^{\prime}\) can be calculated as:  
\[X_{i}^{\prime}=m_{i}(\lambda)X_{i}, \tag{14}\]  
where \(m_{i}(\lambda)\) is the \(i\)-th element of the modulating vector \(\mathbf{m}(\lambda)\). \(\mathbf{m}(\lambda)\) depend on Lagrange multiplier \(\lambda\) by  
\[\mathbf{m}(\lambda)=\exp(W_{2}\,\text{ReLU}(W_{1}\lambda)), \tag{15}\]  
where \(W_{1}\) and \(W_{2}\) are weights matrices of two fully-connected layers. ReLU and exp are nonlinear activation and element-wise exponential function. The exponential nonlinearity guarantees positive outputs. The modulated feature maps in the decoder involve a similar calculation.  
Figure 3: Visualization of input point and corresponding attention mask generated by the first NLAM. (**a**) the input point cloud Bird. (**b**) head. (**c**) upper surface of the wing. (**d**) belly and under surface of the wing. (**e**) the mask of Bird. (**f**) the mask of head. (**g**) the mask of upper surface of the wing. (**h**) the mask of belly and under surface of the wing.  
Let the SConv layers and NLAMs collectively have learnable parameters \(\theta\), and modulating network has learnable parameters \(\theta\), and the decoding part has parameters \(\phi\) and \(\varphi\). As a result, the overall loss function becomes  
\[\underset{\theta,\phi,\theta,\varphi}{\text{argmin}}\,\sum_{\lambda\in\Lambda} \left[R(\hat{Y};\theta,\phi,\theta,\varphi,\lambda)+\lambda D(X,\hat{X};\theta, \phi,\theta,\varphi,\lambda)\right], \tag{16}\]  
where \(\Lambda\) is a pre-defined finite set of \(\lambda\). \(R()\) is the estimated bitrate of latent features and \(D()\) is the distortion between input point cloud attribute and reconstructed point cloud attribute.  
Although, for features of different layers, the parameters of the modulating network are shared, this mechanism allows multi-level and different modulation in case of more complicated networks in the future. In general, this architecture achieves effective joint training of both autoencoder and modulating network, therefore avoiding training and deploying multiple networks.
## 1 Introduction
The research results demonstrated that the plastic damage concentrated around the top of the column near the built-in gusset tip was the reason for the sudden change in lateral stiffness along the column, due to the existence of the built-in anchorage connection. [PERSON] et al. [21] conducted the large scale quasi-static cyclic experiments of BRB-RCBs using an unconstrained gusset connection, and there was no significant cracking and no cracking of the plastic hinge observed during the testuntil the ductility of the retrofitted structure achieving 8. Based on these large-scale hysteretic experiments of RC bridge bents retrofitted with a BRB, [PERSON] et al. [22] established the refined finite element models, which can satisfy the precise requirements at the system- and component-level. [PERSON] et al. [23] proposed two innovative sliding gusset connections to mitigate the unintended frame action effect, which utilized the sliding mechanism at the gusset-to-frame interfaces. Subassemblage tests revealed that the force transfer path at the gusset-to-frame interface can be shifted by adopting the suggested connections, resulting in a lower shear force and energy dissipation demands on the RC frames. Figure 1: Traditional gusset connection configurations: (**a**) Anchorage connection; (**b**) Embedded steel plate connection; (**c**) Unconstrained connection. Scarce research has focused on the effect of the frame action on the hysteretic behavior of double-pier RC bridge bents with the bolted gusset connections, and the existing studies on the slotted gusset plate did not consider the effect of the different dispositions of the slots. To eliminate the negative effect of the frame action on the BRB-RCBs, a bolted gusset connection was proposed in this study, which has the advantages of a relatively simple configuration, convenient construction and suitability for new and as-built structures. Compared with the unconstrained gusset connection, the bolted gusset can delay the shear failure of the concrete beam under great story drift and provide a greater out-of-plane stiffness on the BRB-to-gusset connection. The finite element model was constructed by ABAQUS and validated through the existing experimental tests. The effects of the different dispositions of the slots for the bolted gusset connection on the seismic performance of BRB-RCBs were investigated.
# Design Methodology and Application Dynamics of Compact Quasi-Zero Stiffness Isolators
###### Abstract  
With the rapid development of precision instruments, aerospace, and automotive industries, the demand for compact vibration isolators capable of suppressing low-frequency vibrations has surged. Although prior reviews have established the theoretical framework of quasi-zero stiffness (QZS) isolators, critical gaps persist in addressing their compact design under strong nonlinear dynamics and diverse engineering constraints. This review systematically analyzes the dynamic characteristics of QZS systems under nonlinear effects and evaluates five innovative design methodologies for compact QZS isolators: special spring type, magnetic type, bionic type, metamaterials-based type, and origami-inspired type. Key findings reveal that special spring-type isolators are simple to design and space-efficient but difficult to machine. Magnetic-type isolators achieve ultra-low start-up frequencies but face thermal instability. Metamaterial designs enable multifunctional integration at the cost of manufacturing complexity, while bionic-inspired and origami-inspired isolators are difficult to abstract for practical applications. We find that current research tends to prioritize miniaturization over the synergistic optimization of load capacity, broadband isolation, and adaptability. Future research should focus on multi-degree-of-freedom systems, coupled metamaterials-bionic structures, and active magnetic control. This work provides a key roadmap for advancing compact QZS technology in space-constrained applications.  
Keywords:quasi-zero stiffness; nonlinear dynamics; compact design +
Footnote †: journal: Applied sciences
# Nonlinear Dynamic Response of a Precast Concrete Building to Sudden Column Removal
## 4 Results and Discussion
### Edge Column Removal Scenario  
#### 4.1.1 Moment Resisting Frame System (MRF_E)  
The moment resisting frame system subject to edge column removal scenario is investigated herein. Figure 5(a) shows the structural response results in terms of vertical displacement recorded at the location of the removed column and failure propagation occurring at the 1 st floor level during progressive collapse phenomenon. Such responses are reported for the design load corresponding to accidental combination (100%-\(Q_{b,e}\) in Table 1 for edge location) and increased load (170%-\(Q_{b,e}\)). This procedure was adopted to establish the effective structural capacity of the selected MRF system subject to edge column loss compared to the gravity load demand. For the sake of simplicity, the sequence of failure events under increased load case is described. It is worth to note that the structure was able to sustain the increased gravity loads due to no rebar fracture occurrence and limitation of vertical displacement dictated by the 1 st floor height equal to 3.3 m. Thus, the collapse load was not reached. At early stage, the first failure event was associated with the almost contemporary yield of tensile longitudinal rebars in correspondence of removed column (1-2 and 1-3 locations) and adjacent columns (1-1 and 1-4 locations) at 0.16 s (Figure 5(b)). This event was followed by the achievement of the concrete core peak compressive stress at adjacent columns (1-1 and 1-4 locations) at 0.30 s (Figure 5(c)).  
In Figure 5(d), the axial load in beams above the removed column are reported. At early stages, the compressive arch action was activated due to lateral frame stiffness. At a vertical displacement level of about 820 mm, the transition from compressive to catenary action occurred. A peak tensile load of 2000 kN was recorded until the equilibrium state was achieved. It is noted that similar delayed events occurred at the different floor levels. No brittle shear failures were detected.
# Enhanced Ant Colony Algorithm Based on Islands for Mobile Robot Path Planning
###### Abstract  
Path planning in complex environments presents a substantial research challenge for mobile robots. This study introduces an enhanced ant colony algorithm based on islands (EACI) for mobile robot path planning. First, the original map's grid cells--which could potentially cause ants to become trapped in deadlocks--are transformed into obstacles. This process generates an auxiliary map, where a specified number of islands are evenly distributed between the starting and end grids. Second, an irregular pheromone initialization strategy is employed to enhance the information transmission between neighboring islands. Concurrently, the heuristic function is refined, and an adaptive evaporation coefficient is incorporated to facilitate dynamic adjustments in pheromone updates. These modifications effectively reduce the number of iterations required and decrease the incidence of deadlock among the ants. Third, the performance and advantages of the EACI are validated in various grid maps. Simulation results demonstrate that, compared to other optimization algorithms, the EACI method provides superior path solutions, achieves faster convergence, and reduces the number of lost ants. In \(20\times 20\), \(30\times 30\), \(40\times 40\), and \(50\times 50\) environments, the average numbers of iterations are 1, 1.4, 6.2, and 7.1, respectively, while the average numbers of lost ants are 9.85, 27.5, 47.6, and 99.2, respectively--demonstrating strong stability and adaptability. Finally, real-world experiments validate the algorithm's effectiveness.  
auxiliary map; deadlock ants; islands; lost ants; pheromone initialization; path planning Article
## 2 Modeling of Tethered UAV Dynamics
### Modeling of Tethered Cables  
#### 2.2.1 Modeling Assumptions for Tethered Cables  
To model the tethered cable more accurately, the force of the cable needs to be analyzed. When the tethered UAV is in vertical lifting and lowering, the tethered cable only has a longitudinal force on the UAV platform. When the UAV platform moves horizontally, the tethered cable is in a state of traction, and the current force situation is complicated. Before proceeding with the force analysis, some assumptions about the tethered cable should be made to simplify the process and highlight the key points.  
(1) The tether cable is assumed to be flexible. It can only withstand tensile forces but not pressures or bending moments [21]. Such an assumption is based on the physical properties of the cable material, which makes it possible to ignore the bending and compression deformation of the cable during force application during the analysis.  
(2) It is assumed that the linear density of the tethered cable is constant. The material is uniformly distributed, and the cable is subjected only to self-weight loads that are uniformly distributed along the arc length. This means that the weight of the cable is uniformly distributed and does not change due to the change of position, which helps better calculate the forces on the cable in different states.  
(3) It is assumed that the tethered cable's elongation effect will not occur during the UAV's movement. This assumption is based on the elastic properties of the cable material, which simplifies the deformation analysis of the cable when subjected to forces.  
(4) Considering that the UAV mainly works in a breezy or windless environment, the disturbance effect of the lateral breeze is ignored here. This assumption helps to focus on the interaction between the tethered cable and the UAV rather than the impact of the external environment on the system.
## 4 Effect of Environmental and Physiological Parameters in the Synthesis of Nanoparticles  
It is imperative to learn the critical impact of environmental and physicochemical parameters on the synthesis processes for NPs [66]. Studies have shown that even the smallest changes in the value of these parameters can have major impact on the overall synthetic outcome for NPs, which is variable. Sometimes a change in any of the parameter may prevent the synthesis of NPs or change in the parameter lead to an alteration in the stability, size or shape of the synthesized NPs. Furthermore, it need to be emphasized here that scientists carefully conduct their studies and record the affecting parameters involved in the synthesis process to help improve the reproducibility of their work; optimizing separately the effect of each parameter on the synthesis process of NPs is thus crucial. Such thorough and meticulously conducted studies can help us to synthesize NPs with desired structure, stability, size, or shape. Sometimes, the synthesis of NPs using specific biological source may not be successful initially. In such cases, it is possible to explore synthesis of NPs by changing the environment and physico-chemical parameters. [PERSON] et al. [67] studied the effect of temperature on the synthesis of gold NPs using extract from _Semecarpus anacardium_ L. They reported that higher temperatures lead to synthesis of spherical NPs, while lower temperatures lead to the synthesis of mainly triangular NPs. [PERSON] et al. [48] reported that the synthesis at elevated temperatures lead to large-sized and more stable NPs than at lower temperatures.
## 3 Results
### Gaseous Products  
Figures 4-6 represent the evolution profiles of the gaseous products of pyrolysis, and Figure 7 compares the higher heating value of gases produced at 450 \({}^{\circ}\)C from all the studied fuels. For the woody samples, evolution of CO\({}_{2}\) with a peak rate at 350-370 \({}^{\circ}\)C was associated with the splitting of C-C and C=O bonds due to the thermal decomposition of hemicelluloses and cellulose components. CO, showing peak intensities at 350-360 \({}^{\circ}\)C, could not only arise from the degradation of these constituents but also from the splitting of C-O-C and C=O bonds during the decomposition of lignin at higher temperatures. The formation of CO above 450 \({}^{\circ}\)C, in the case of PCO fuel, was a result of charring processes, creating a more condensed aromatic structure [5]. This is in accordance with the results in Table 2, presented earlier, where PCO showed the highest degree of carbonization among the samples examined. In contrast, the enhanced CO\({}_{2}\) generated by FOR and RDF fuels reveals the decomposition of carboxylic acids [5]. Furthermore, the lower temperature peak of CH\({}_{4}\) at \(\sim\)350 \({}^{\circ}\)C, during the pyrolysis of FOR and RDF, was most probably attributed to the splitting of the -OCH\({}_{3}\) functional group [5], while the higher temperature peak of CH\({}_{4}\) at \(\sim\)480 \({}^{\circ}\)C for PCO was due to charring processes. The small amounts of C\({}_{x}\)H\({}_{y}\) and H\({}_{2}\) produced at higher temperatures were associated with the splitting of stronger aliphatic or aromatic bonds. The higher heating values of PCO and RDF gases, consisting mainly of CO, were moderately high (13.6-13.8 MJ/m\({}^{3}\)) and were satisfactory for the energy requirement of the process [5]; however, the value of FOR gas produced at 450 \({}^{\circ}\)C was low (7.1 MJ/m\({}^{3}\)) as the evolution of CO from this fuel was found to cease at this temperature.  
Figure 4: Evolution profiles of (**a**) CO and CO\({}_{2}\) and (**b**) H\({}_{2}\), CH\({}_{4}\) and C\({}_{x}\)H\({}_{y}\) of PCO pyrolysis.  
Figure 5: Evolution profiles of (**a**) CO and CO\({}_{2}\) and (**b**) H\({}_{2}\), CH\({}_{4}\) and C\({}_{x}\)H\({}_{y}\) of FOR pyrolysis.  
Figure 6: Evolution profiles of (**a**) CO and CO\({}_{2}\) and (**b**) H\({}_{2}\), CH\({}_{4}\) and C\({}_{x}\)H\({}_{y}\) of RDF pyrolysis.