esa-sceva/satcom-chunk-collection huggingface dataset:
# Analysis of Elastic Nonlinearity Using Continuous Waves: Validation and Applications
## 3 Validation
### Feasibility of the Separation of Modulus and Damping Contributions
#### 3.1.3 High Linear Damping  
As mentioned, Equation (3) suggests that nonlinearity of the damping parameter \(\lambda\) has influence on nonlinearity in velocity \(c\). Normally, the damping contribution to velocity is negligible, but this is no longer true when \(\lambda_{0}\) is large. Here, the goal is to prove that the approach proposed in this paper can also deal with such extreme cases.  
To this purpose, we compare the results of Figure 3 (obtained when linear damping is low: \(\lambda_{0}=6.48\times 10^{2}\) s\({}^{-1}\)), with those obtained in the case of high linear damping (\(\lambda_{0}=3.24\times 10^{3}\) s\({}^{-1}\)), reported in Figure 5. Details on nonlinear parameters used in simulations for all the cases, are reported in the table of Figure 1. Note that in Case B only the modulus was chosen to be nonlinear (\(\delta_{S}\
eq 0,\delta_{\lambda}=0\)) and its nonlinearity is supposed to have a small effect on attenuation nonlinearity; in Case C only the damping was chosen to be nonlinear (\(\delta_{S}=0,\delta_{\lambda}\
eq 0\)) and its nonlinearity is supposed to have a small but identifiable effect on velocity nonlinearity.  
Hence, it is possible to note that:  
* Case A: As expected, in the linear case, there are no variations on both velocity and attenuation coefficient.
* Cases B and D: In both cases, nonlinearity in \(c\) (Case B) or both in \(c\) and \(\alpha\) (Case D) are observed, as expected. For attenuation coefficients with respect to the expected behaviour for the two cases, this is not the case for the estimated velocity nonlinearity, even though the nonlinear modulus  
Figure 5: Effects of damping nonlinearity on velocity in the case of strong linear damping: behaviour of \(\Delta c/c_{0}\) and \(\Delta\alpha/\alpha_{0}\) vs. amplitude \(A\) for different nonlinear conditions. The same colours were used in the two subplots and are related to the cases reported in the legend.  
parameters are the same for the two cases. The slight difference (appreciable for high strain levels) is due to the small damping contribution to velocity nonlinearity when damping is strong.
* Case C: In this case, the effects of damping nonlinearity on velocity are more easily appreciated. In fact, the imposed quadratic nonlinearity on damping induces nonlinearity on attenuation coefficient as well as on velocity (green circles).
## 2 Mixed Mode Fatigue Life Evaluation Procedure Using ANSYS  
ANSYS can model three kinds of cracks: arbitrary, semi-elliptical, and pre-meshed. The pre-meshed crack method requires the crack front used by the Smart Crack growth analysis tool (SMART), whereby the stress intensity factor is the criterion of failure. The node sets that have been rendered will be distributed to the front of the crack and to the top and bottom of the crack. The latest feature presented in ANSYS is the \"Smart Crack Growth,\" mesh-based tetrahedron, which adds the \"pre-meshed crack\" requirement after completion in which the user can choose the type of crack growth option. To accommodate the crack growth changes, SMART uses a combination of automatic morphing, adaptive, and remeshing methods. SMART automatically updates the mesh from crack-geometry changes caused by crack growth at each solution step. Mesh updates occur exclusively around the crack-front region and are integrated into the Mechanical APDL solver without exiting and reentering the solver, leading in a computationally efficient crack-growthsolution. The mesh around the crack tip can be refined using the process of the sphere of influence around the geometric edge that passes through the thickness. The geometric regions to be described are the crack tip, the top surface of the crack, and the bottom surface of the crack. Instead, each of these regions is associated with a node set to be used for analysis. The ANSYS software considers mixed-mode loading, where the maximum circumferential stress criterion is implemented. The following are the formulas for the direction of crack propagation in ANSYS [28; 29]:  
\[\theta=\cos^{-1}\left(\frac{3K_{II}^{2}+K_{I}\sqrt{K_{I}^{2}+8K_{II}^{2}}}{K_{ I}^{2}+9K_{II}^{2}}\right) \tag{1}\]  
where \(K_{I}\) = Max \(K_{I}\) during cyclic loading and \(K_{II}\) = Max \(K_{II}\) during cyclic loading.  
In ANSYS Mechanical APDL 19.2, by using XFEM, the simulation of crack growth is restricted to region II of the typical fatigue crack growth graph, which can be represented as:  
\[\frac{da}{dN}=C(\Delta K_{\alpha q})^{m} \tag{2}\]  
From Equation (2), for a crack increment, the number of life cycles of fatigue may be predicted as:  
\[\int\limits_{0}^{\Delta a}\frac{da}{C(\Delta K_{\alpha q})^{m}}=\int\limits_{0 }^{\Delta N}dN=\Delta N \tag{3}\]  
The equivalent range for the stress intensity factor formula can be found as follows [28]:  
\[\Delta K_{eq}=\frac{1}{2}\cos\frac{\theta}{2}[(\Delta K_{I}(1+\cos\theta))-3 \Delta K_{II}\sin\theta] \tag{4}\]  
where \(\Delta K_{I}\) = the stress intensity factor range in mode I loading and \(\Delta K_{II}\) = the stress intensity factor range in mode II loading. The ANSYS flow chart is shown in Figure 1.  
Figure 1: ANSYS flow chart for SMART crack growth simulations.
## 8 Study Limitations and Future Research Directions  
As discussed in previous sections, one of the limitations of the study is the determination of criteria weights, which has been done according to the AHP method assuming criteria independence. In future research, this issue should be addressed so that it is studied how the correlation of the criteria influences the weighting of the criteria and to consider other methods of decision-making that allow this correlation to be taken account. Furthermore, in future studies, the methodology can be improved to avoid the phenomenon of \"rank reversal\" when an alternative is added or removed.
# GNSS-Assisted Visual Dynamic Localization Method in Unknown Environments
## 2 GNSS-Assisted Visual Dynamic Localization Method Framework
### Subsequent Frame Sequence GNSS Coordinate-Solving  
When the position of the subsequent image in the world coordinate system was obtained, the GNSS coordinates of the subsequent sequence of frames could be obtained by solving jointly with \(\mathbf{R}_{W}^{n}\). The following equation took \(I_{4}\) as an example, and it solved the position of \(C_{4}\) in the GNSS coordinate system as follows:  
\[X_{C_{4}}^{n}=X_{C_{1}}^{n}+\mathbf{R}_{W}^{n}t_{C_{4}}^{C_{1}} \tag{15}\]
# Similarity-Driven Edge Bundling: Data-Oriented Clutter Reduction in Graphs Layouts
## 4 Results and Evaluation  
In this section, we evaluate _Similarity-driven Edge Bundling_ (_SDEB_) three main components: the STree algorithm to create the _backbone_, the swapping version of the H-Tree layout algorithm to preserve distance information, and the entire edge bundling process. We quantitatively compare the STree and swapping HTree strategies with their existing counterparts, and assess the entire bundling method qualitatively comparing with other bundling techniques.
## 3 Experimental Results and Discussion
### Load-Carrying Capacity
#### 3.1.2 Effect of TMS Plate Thickness  
When comparing the specimens with different plate thicknesses but similar perforated hole arrangements, the specimens with a plate thickness of 2.0 mm showed a higher load-carrying capacity than those of 1.5 mm and 2.5 mm plate thickness. This may be due to insufficient stiffness in the 1.5 mm thick plate to withstand the shear force induced in the specimens. Plates with 2.5 mm thickness are too stiff, resulting in a large difference between the relative stiffnesses of the concrete and plate. This reinforces the finding by [PERSON] and [PERSON] [6]. Thus, internal force initially resisted by the concrete may  
Figure 5: Ultimate load for each specimen.  
not be transferred effectively to the steel plate, causing a lower ultimate load attainment in the specimens with 2.5 mm thick TMS plates.
# Three-Level Hybrid Envelope Tracking Supply Modulator with High-Bandwidth Wide-Output-Swing
## 2 Supply Modulator System Level Design  
The three-level hybrid structure used in this paper is shown in Figure 2 and mainly composed of three parts: (1) a linear amplifier; (2) a switching regulator; and (3) a hysteresis control loop. The load resistance R\({}_{\text{Load}}\) is equivalent to the supply node impedance of a RF PA. In general, linear amplifiers are characterized by high bandwidth and low efficiency, mainly processing the high-frequency part of the input signal and absorbing the noise current generated by the SWR. The switching regulator has the advantage of high efficiency and mainly deals with the DC and low-frequency parts of the input signal. The hysteresis control loop, as a connection between the linear stage and the switching stage, can control the on-off of the switching MOSFET.  
The efficiency of the hybrid ET modulator can be expressed as  
\[\eta=\frac{P_{out}}{P_{out}+P_{loss}} \tag{1}\]  
where \(P_{out}\) is the average output power of the ET modulator and \(P_{loss}\) represents the total power loss. The control loop is mostly logic devices, the power loss is less, so the \(P_{loss}\) is mainly concentrated in the linear stage and the switching stage.  
This section will introduce the main blocks of the circuit and analyze the system power consumption.  
Figure 1: The system block diagram of the hybrid ET modulator.
# Opportunistic and On-Demand Network Coding-Based Solutions for LPWAN Forwarding
## 1 Introduction
We cannot rely on retransmission as the strict regulation of 1% duty-cycle constraint makes acknowledgment-based ineffective because the gateway has to send ack at the specified time-slot. The majority of previous LPWAN forwarding studies are based on fixed-path forwarding that immediately forwards the received packets via a predetermined path [9; 10; 11; 12; 13]. The other studies adopt flooding transmission that allows synchronized packet collision [14; 15]. However, both approaches only consider improving high reliability and low latency. They do not consider the trade-off between  
Figure 1: Ideal use of a relay. Not all end-devices require relays to preserve reliability. Relay is only useful for extending coverage and forwarding packet from a blocked end-device. network reliability and capacity issues caused by unnecessary forwarding. This paper presents opportunistic and on-demand network coding (OODC) forwarding to increase the LPWAN coverage with improved reliability and transmission efficiency. As the header overhead of network coding may exceed the size limitation of the LPWAN packet, we use a header compression technique to counter the increase. The contributions of our work with respect to LPWAN forwarding are as follows:  
* Adoption of opportunistic forwarding that considers transmission over a shared wireless environment. Without predetermining a forwarding path, we allow any relays to forward the packet. Hence, we can increase transmission reliability and network throughput. * Adoption of on-demand/feedback message based forwarding in the relays instead of proactive forwarding to prevent unnecessary duplicate forwarding. * Adoption of a random linear network coding (RLNC) to tackle the bottleneck problem in opportunistic forwarding. Because of the LPWAN packet size limitation, we employ header compression to reduce RLNC header overhead. * Through simulation, we show that a relay increases the network coverage and improves the network reliability with better efficiency by utilizing a multiple fast data rate instead of a single slow data rate. The paper goes on to discuss related works in Section 2, motivation for LPWAN forwarding concept in Section 3, study on LoRa in Section 4, design and forwarding operations in Section 5, and implementation and evaluation in Section 6, followed by conclusions and future directions of work.
# Optical Pupil Shift Correction Method for Large Ground-Based Optical Telescopes
## 3 Calculation of Optical Pupil Shift and Active Compensation
### Process of Optical Pupil Shift Compensation  
During the tracking process of the telescope, the deviation in the positions of the primary and secondary mirror induced by the structural deformation affected the wave aberration of the primary system. The change in the optical axis of the primary system led to the optical pupil shift, which ultimately affected the efficacy of correction of the adaptive optical imaging system. The aberration and optical-axis deviation vary with the telescope elevation angle. Based on the coma-free theory of the Cassegrain system, these defects can be compensated by adjusting the position and attitude of the secondary mirror by manipulating the Hexapod platform. The specific compensation process is illustrated in Figure 6.  
Figure 4: Diagram of pupil shift caused by deviation of primary mirror position.  
Figure 5: Diagram of pupil shift caused by deviation of secondary mirror position.  
First, the current position of the primary and secondary mirror nodes is calculated by Equation (3). Then, based on the current position of the secondary mirror, the coma-free rotation point of the primary and secondary mirrors is calculated using the coma-free rotation point theory. This rotation point is used as the reference, and the calculation of control inputs to the Hexapod platform based on target imaging off-target amount. Thus, the shift is compensated. Finally, the compensated shift is analyzed and evaluated using the adaptive optical correction effect.
# A Petri Net Model for Cognitive Radio Internet of Things Networks Exploiting GSM Bands +
## 1 Introduction
Moreover, the non-Markovian stochastic Petri net (NMSPN) class was used to exploit two of their main features: (1) the ability to correctly represent non-exponentially distributed time events; and (2) the memory policies for modeling suspend/resume behaviors. In this work, we characterize both the throughput and time delay of a cognitive radio network operating in a GSM channel using an NMSPN model of the traffic that is generated by the PUs. Specifically, in order to reduce interference with PUs, our approach takes into account synchronized SUs, which are able to recognize the GSM time slot boundaries. In order to avoid interference with the PUs, each SU device must listen to the channel at the start of each slot, and it can only begin transmission if it verifies no PU activity. Moreover, the frame length of each SU must not span over the final boundary of the slot; accordingly, several frames will be necessary to transmit a single information unit. In [20], we already proposed the same approach in order to characterize both the throughput and time delay of a cognitive radio network operating in the channel of a GSM transponder. In this work, we introduced the modeling of the discontinuous transmission to better characterize the behavior of speech phone calls, and we mostly extended the previous model in order to take into account both the circuit switching and packet switching traffic of a GSM/EDGE transponder. \begin{table}
\begin{tabular}{l l l} \hline \hline
**Operating Band** & **Uplink Frequencies** & **Downlink Frequencies** \\ \hline GSM450 & 450.4-457.6 MHz & 460.4–467.6 MHz \\ \hline GSM480 & 478.8-486.0 MHz & 488.8–496.0 MHz \\ \hline GSM850 & 824.0–849.0 MHz & 869.0–894.0 MHz \\ \hline GSM900 (primary) & 890.0–915.0 MHz & 935.0–960.0 MHz \\ \hline GSM900 (extended) & 880.0–915.0 MHz & 925.0–960.0 MHz \\ \hline GSM900 (railways) & 876.0–915.0 MHz & 921.0–960.0 MHz \\ \hline DCS1800 & 1710.0–1785.0 MHz & 1805.0–1880.0 MHz \\ \hline PCS1900 & 1850.0–1910.0 MHz & 1930.0–1990.0 MHz \\ \hline \hline \end{tabular}
\end{table} 
Table 1: GSM frequency bands. The rest of the paper is organized as follows. In Section 2, we analyze the most relevant works related to this research. In Section 3, we characterize the cognitive environment through the analysis of the primary and secondary users transmission methods. The NMSPN models used to capture the behavior of the cognitive environment and evaluate the QoS are introduced in Section 4. Section 5 describes the results obtained by evaluating the models; finally, Section 6 concludes our work.
# Observing APOD with the AuScope VLBI Array
## 4 Correlation and Post-Processing  
Our goal was to stay as close as possible to the processing scheme that is operationally applied for geodetic VLBI sessions. Therefore, we adopted the use of standard software tools for observations  
Figure 3: APOD signal and recording channel allocation in the frequency domain. The 16 MHz recording channels are illustrated by red (X-band, upper side band), blue (X-band, lower side band), and cyan (S-band, upper side band) boxes. The APOD tones are indicated as black lines with the carrier having a larger amplitude than the surrounding DOR tones. The X-band signals span over 38.3 MHz and were recorded in three 16 MHz channels (upper and middle panels). The S-band tones are covered by one 16 MHz channel centered at the carrier (bottom panel).  
of the APOD satellite: the software correlator DiFX [28] and the Haystack Observatory Post-processing System (HOPS).
# Integrating Multi-Access Edge Computing (MEC) into Open 5G Core
## 2 5G System
### 5G Core  
The 5 GC network features an innovative architecture called SBA, which revolves around services and microservices [6]. In this model, the 5 GC introduces characteristics such as the separation between the DP and the CP, function virtualization, and Network Slicing (NS) [17].  
The SBA offers advantages such as improved development and maintenance efficiency, the association of microservices with dedicated resources and independent lifecycles, and enhanced scalability through on-demand instances [8]. This structure consists of network functions (NFs) that provide services through the Service-Based Interface (SBI), accessed via APIs and protocols like HTTP, REST, and others [17].  
The 5 GC is an integral part of the 5 GS alongside the New Radio (NR) radio interface. Built upon cloud computing concepts, the 5 GS features a service-oriented core with SBA architecture, natively supporting NS, virtualization, and edge computing [28]. The architecture of the 5 GS is divided into two modes: non-standalone (NSA), where the new radio interface is used in conjunction with an existing core infrastructure (Evolved Packet Core--EPC), and standalone (SA), where the radio interface connects to the newly proposed core architecture for 5G.
# Secure Transmission in mmWave Wiretap Channels: On Sector Guard Zone and Blockages
## 3 Secure Transmission Strategies
### Eavesdroppers Are Detected Beyond the Sector Secrecy Guard Zone  
If there do not exist eavesdroppers within the sector secrecy guard zone, the transmitter keeps sending the confidential information to the legitimate receiver. In this case, eavesdroppers distribute beyond the sector secrecy guard zone to intercept confidential information. Therefore, the SNR at the receiver is defined as  
\[\gamma_{D_{A}}=\frac{PM_{S}|h_{D}|^{2}L\left(r_{D}\right)}{\sigma_{D}^{2}}, \tag{5}\]  
and the instantaneous SNR of detecting the information of the legitimate receiver at the most detrimental eavesdropper is given by  
\[\gamma_{E_{A}}=\frac{\max\limits_{E\in\Phi_{1}}\left(PM_{S}|h_{E}|^{2}L\left(r _{E_{A}}\right)\right)}{\sigma_{E}^{2}}, \tag{6}\]  
or  
\[\gamma_{E_{A1}}=\frac{\max\limits_{E\in\Phi_{2}}\left(Pm_{S}|h_{E}|^{2}L\left( r_{E_{A1}}\right)\right)}{\sigma_{E}^{2}}. \tag{7}\]  
where \(E\in\Phi_{1}\) denotes that eavesdroppers reside in the signal beam out of the sector secrecy guard zone, and then the SNR at the eavesdropper is \(\gamma_{E_{A}}\). \(E\in\Phi_{2}\) denotes that eavesdroppers may reside anywhere except in the signal beam where the sector secrecy guard zone is located, and then the SNR at the eavesdropper is \(\gamma_{E_{A1}}\). The distance \(r_{E_{A}}\) from the eavesdropper to the transmitter is larger than the radius \(r\) of the sector secrecy guard zone. \(r_{E_{A1}}\) is the distance from the eavesdropper to the transmitter in the side lobes, and \(\sigma_{\
u}^{2},\
u\in\{D,E\}\) denotes the additive white Gaussian power.
# Transforming Petrochemical Processes: Cutting-Edge Advances in Kaolin Catalyst Fabrication
## 6 Unlocking the Potential: Advanced Applications of Kaolin in Industry
### Paper Industry  
Kaolin is essential in the paper industry and is primarily used for coating and filling [77; 92]. As a filler, kaolin mixes with cellulose fibers in wood pulp, enhancing the paper's internal structure. For coating, it combines with water, adhesives, and additives, improving smoothness, brightness, gloss, opacity, and printability. Uncoated paper does not meet high-quality printing standards, but the fine particle size and platy shape of kaolinite provide a smooth, dense, and uniformly porous surface for better ink absorption.  
Kaolin's hydrophilic nature makes it easily dispersible in aqueous systems, which is ideal for coating formulations applied to paper surfaces at high speeds. Proper rheology, which should be Newtonian or thixotropic, ensures even coating distribution [93]. Kaolin grades used for coatings typically have particles, of which 80% are less than 2 um. Delaminated kaolins, which are used in lightweight coatings (LWC), offer a shingle-like structure that enhances ink holdout and smoothness, reducing the paper's weight and lowering postal costs for publications. Rheology is crucial for kaolin in paper coatings, with viscosity affected by particle size, shape, surface area, and impurities [80; 94]. Engineered kaolins are designed to improve specific properties like opacity, gloss, and brightness. Kaolin fillers, typically coarser and less bright, mix with paper pulp to enhance brightness, opacity, smoothness, and printability, offering a cost-effective alternative to pulp [95]. Despite the rise of calcium carbonate fillers in neutral/alkaline papermaking, kaolin remains significant in certain applications.  
Additionally, kaolin serves as a fiber extender in automotive gaskets, replacing asbestos due to health concerns, and as a cost-effective extender for titanium dioxide in paper filling and coating, maintaining brightness and opacity while reducing costs [6]. Cal calcined kaolins, with their high brightness and opacity, enhance light scattering and overall paper quality. Major companies, like _Georgia-Pacific_ and _Interys_, utilize kaolin in their paper manufacturing processes to improve surface properties and printability.