esa-sceva/satcom-chunk-collection huggingface dataset:
# Communication Infrastructure Design for Reliable UAV Operations in Air Mobility Corridors
### Related Works
To support its development, the 3 rd Generation Partnership Project has been actively working on standardizing critical technologies, including satellite radio access, NTN core systems, and NTN-supported Internet of Things (IoT) applications [20]. As a key technological pillar of future 6G networks, SAGINs are anticipated to reshape the foundational architecture of global communication systems. Despite its potential, the advancement of SAGIN faces considerable challenges. One major issue stems from the vulnerability of end-to-end communication between space and ground segments. These links can be severely impacted by adverse weather conditions and space weather phenomena such as solar storms, compromising connectivity and reliability. In densely built urban environments, additional challenges arise, as satellite-ground signals are often weakened or blocked due to building penetration losses and signal attenuation caused by obstacles [20; 21]. The paper [22] provides a systematic review of UAV-assisted SAGINs, which are enhanced with 6G technology to offer seamless coverage and efficient connectivity by integrating terrestrial, aerial, and satellite networks. It explores the hierarchical architecture, the dynamic characteristics of SAGINs, and the specific roles of UAVs within this framework. The paper [23] explores the development of UAM, a burgeoning aviation sector that leverages electric vertical takeoff and landing aircraft for secure, efficient, and environmentally friendly transportation in urban, suburban, and remote areas. The paper highlights challenges such as inadequate wireless coverage in dense urban areas and disconnected rural settings, which complicate large-scale deployment of UAM. It also addresses issues in air-to-ground connectivity that could overload terrestrial networks and impact link reliability during the immediate recovery phase. It discusses the necessity of high connectivity to manage eVTOL traffic in crowded urban skies. The study [24] addresses the challenges facing UAV-assisted air-to-ground data transmissions, including issues with terminal mobility, channel fading, resource constraints, and specific transmission requirements. The multi-link communication model offers significant advantages overrelying on a single data link [25; 26; 27]. One of its primary benefits is the increase in redundancy, which enhances system reliability. Additionally, it improves the overall performance of the communication network, ensuring that various applications can function effectively even under differing or dynamic operational conditions.
## 4 Mechanical Properties of Lattice Structures Built with Polygonal Hollow Shapes
For polygonal hollow structures, the critical buckling loads were observed to be influenced by the shape and size, strut thickness, and material properties of the specific polygon used [8; 17; 18]. The resistance of a polygon hollow structure to the propagation of cracks was also noted to be critical for its endurance. It was noted that the fracture toughness of the hollow structure was also influenced by the choice of materials and the degree of imperfections or notches inherent in the structure [3]. Heat exchangers and other applications requiring thermal properties were observed to often use lattice architectures [13; 48; 49; 50]. The heat transfer and thermal conductivity of lattice structures are both known to be affected by the shape and configuration of polygonal structures [17]. Polygon hollow structures are capable of damping vibrations at different levels, determined by the choice of lattice design and material properties [13; 51]. This could prove useful in applications where controlling vibration is critical. In addition, the processes of manufacturing polygon hollow structures, such as AM (3D printing) or conventional machining, could have a bearing on their mechanical properties [11; 12; 13; 14; 15; 19]. Thus, it is known that complex lattice structures that are difficult to fabricate using conventional techniques are now attainable using AM technologies [15; 19; 38]. When designing lattice structures using polygonal hollow shapes, it is important to strike a balance between the structural performance and reduction in weight. Computer-aided design (CAD) and simulation technologies can assist in optimising the design to meet specific mechanical requirements for a specific use. Additionally, experimental testing and validation are often required to confirm whether the lattice structure behaves as envisioned through design in general engineering applications. Cutting-edge manufacturing technologies such as AM are strongly recommended for incorporation into the design and manufacturing procedure of lattice structures [8; 9; 10].
# A Review of PCI Express Protocol-Based Systems in Response to 5G Application Demand
## 3 Technology Analysis Using PCI Express, CXL, USB, NVMe, and Security
### Universal Serial Bus (USB)  
According to the USB industry standard roadmap, USB 4.0 with Thunderbolt 3 will provide more extended features across the USB topology. These include more combined features with USB, Display Port (DP), PCI Express (PCIe), and Power Delivery (PD) for power, as shown in Figure 7[24; 33].  
Although the USB 4.0 specifications are combined with Thunderbolt 3, Thunderbolt 4 still uses the PCIe4.0 16 Gb/s per lane in a chipset with multiple serial GPIO design for the features combined within. USB uses lanes to transfer data through the UBS connector; the ideal speed to transfer data is from 2560 MB/s to 5120 MB/s [24; 34; 35]. This bandwidth and data transfer rate should enhance the capability of the system to run other protocols through USB. The USB 4.0 topology is shown in Figures 8 and 9[24], including the layers with routers, as the design structure for USB, PCIe, and Display Port (DP); these data protocols with layers transition through a high-speed serial bus.  
Figure 6: NVMe topology in PCI Express [23].  
Figure 7: USB 4 protocol topology [24].  
Power is delivered through a PD protocol using the USB PD power source [36]. This capability enhances the system design, allowing the capability to reduce the design in terms power scope, as shown in Figure 10[37]. USB 3.1 is combined with power delivery specifications to change the AC-DC capability through the USB interface across the platform's design.  
Figure 8: USB 4 function stack layers [24].  
Figure 9: USB 4 communication by function layer [24].  
Power is delivered on-demand through the PD, as shown in Figure 10[37]. For a platform designed with a programmable power supply under 15 W up to 100 W, a PC system could use these mechanisms to design a power tolerance system, in order to identify the system as a performance-based system for power saving and to customize the system for specific products.
## 4 Components and System
### Antennas
#### 4.2.2 Simulation and Measurement
The gain in the main direction corresponds directly to the average value of the gain from Figure 11 measuring 6.6 dBi. In summary, a small and cost-effective solution was found with the realized Vivaldi antenna. The antenna shape can be arbitrarily adapted to the requirements of the specific measurement scenario. Manufacturing in common PCB processes is possible, which means  
Figure 11: Simulated and measured gain of the main lobe versus frequency. Figure 12: Simulated and measured antenna pattern at center frequency of 10 GHz and \(\Phi=0\). Figure 13: Measured antenna pattern averaged over the frequency range of \(8\ldots 12\) GHz and \(\Phi=0\). that a larger number of antennas can also be used for complex arrays without any problems. The performed measurements agree very well with the preceding simulations and the antenna shows good performance for broadband applications.
## Penetration-Type TDR (PTDR)
### Design  
A PTDR was developed in this study to evaluate the water content in the active layer along the depth when the ice lens in the ground was melted. The PTDR consists of a PTDR module, connecting rods, ruler, and a guide with a hammer, as shown in Figure 1.  
Figure 2 shows the shape of the PTDR module, which was designed as a tapered rectangle with a width ranging from 20 mm to 22 mm to enhance the contact between the electrodes and soil. For the measurement of the velocity of electromagnetic waves, three electrodes, each having a thickness of 1.5 mm and a length of 80 mm, were mounted onto the surface of the PTDR module. The three electrode-type probe generally provides a more distinct reflection than two electrode-type probes [35]. The PTDR module was fabricated of monomer-cast (MC) nylon to insulate the spaces between the electrodes, while the tip of the PTDR module was made of stainless steel to minimize the abrasion during penetration. Figure 2 shows the connection of the PTDR module with a co-axial cable of 3 m length. A central electrode installed in the PTDR module as a signal line was connected to the inner co-axial cable, and the other two electrodes were connected as ground lines to the outer co-axial cable. To measure the temperature, a thermocouple was installed diametrically opposed to the module, on the surface of the PTDR module. To reduce the friction along the connecting rod with  
a diameter of 22 mm during penetration, an expanded coupling with a diameter of 24 mm was used behind the PTDR module.  
The hammer, with a weight of 78.8 N, was used for driving the PTDR into the soil. To place the PTDR module at the desired depth, the falling height of the hammer can be changeable during penetration. To transmit and record the reflection signals, a co-axial cable was connected to the TDR unit (Hyperlabs, HL1101); the TDR unit then functions as a pulse generator and an oscilloscope. The 256 detected signals were averaged to minimize the electromagnetic noise, and the signal in the time domain was then recorded.  
After soils thaw, the water amount distributed in the active layer can be determined by driving the PTDR, placing the PTDR module at the desired depth, and measuring the TDR waveform. In the following chapter, the relationship between the dielectric constant obtained from the PTDR and water content will be used to estimate the water content in the active layer. Compared to the conventional methods such as digging a pit, the PTDR requires less labor and minimizes soil disturbance. Furthermore, the PTDR can easily be used to survey the water content distribution in the field, while the TDR probes embedded in the soils enable the monitoring of water content only at a fixed position.  
Figure 1: Schematic drawing of PTDR connected to the measurement system.  
Figure 2: Schematic drawing of the PTDR module: (**a**) top view; (**b**) side view. The units are in millimeters. The thickness of the electrodes is 1.5 mm.
## 4 Discussion
Future research could also expand on this by investigating how these measurements correlate with clinical improvements, treatment efficacy, and other related outcomes. Building on these findings, this study highlights the potential of accessible and cost-effective tools, such as digital goniometers and smartphone applications, to improve the assessment and management of AHP. The dynamic evaluation of AHP offers valuable insights into compensatory mechanisms and their impact on movement and stability, paving the way for targeted interventions and better patient outcomes. Expanding research in this area will enhance the ability to develop effective, multidisciplinary treatment strategies and broaden access to care across diverse populations. Conceptualization, G.B., P.N. and V.C. ; methodology, G.B., F.B. and E.V. ; software, F.A. ; formal analysis, S.C.; data curation, S.C.; writing--original draft preparation, S.C., F.B. and G.B. ; writing--review and editing, L.D., F.A., M.G., F.N., E.V., P.N. and V.C. ; supervision, G.B. and V.C. All authors have read and agreed to the published version of the manuscript. This research received no external funding. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The study was approved by the Ethics Committee of the University of Milan on 2 April 2020 (protocol n. 29/20). Informed Consent Statement: Informed consent was obtained from all subjects involved in the study. Holically available datasets were analyzed in this study. This data can be found here: [[https://zenodo.org/records/14986726](https://zenodo.org/records/14986726)]([https://zenodo.org/records/14986726](https://zenodo.org/records/14986726)) (accessed on 7 March 2025). The authors declare no conflicts of interest. The following abbreviations are used in this manuscript:  
AHPAnomalous head posture;  
RomRange of motion;  
DGDigital goniometer.
## 3 Future Perspectives  
While this Special Issue showcases significant advancements, it also highlights opportunities for further exploration:  
* Interdisciplinary Collaboration: Bridging optics, artificial intelligence, and materials science can unlock new capabilities for digital holography in diverse applications [36].
* Portability and Miniaturization: Developing compact, field-deployable holographic systems will enhance the practical utility of this technology in real-world scenarios [37; 38].
* Sustainability in Innovation: Incorporating eco-friendly materials and energy-efficient designs will align holographic technologies with global environmental goals [39].
* Widening Application Scope: Expanding digital holography into untapped fields such as environmental monitoring and advanced manufacturing could drive significant breakthroughs [40; 41].
# On the Performance of LDPC-Coded Large Intelligent Antenna System
## 3 System and Signal Model for the Receivers
### Linear Feedforward Non-Iterative FDE Receivers
#### 3.1.4 Equal Gain Combining  
It has been demonstrated that Equal-Gain detection receivers perform generically well in terms of average error probability of symbol [22]. Simple hardware complexity is all that is expected for Equal Gain Combiners at the \(i\)th receiving antenna. Equalization is performed at the receiver by dividing the received symbol \(y_{i}\) by phase \(h_{i}\). This is represented by the polar form \(h_{i}e^{i\theta}\) of the channel \(h_{i}\).  
The total number of phase-compensated channels received by all antennas makes up the encoded symbols [23]. Using the EGC algorithm, \(F_{k}\) becomes:  
\[F_{k}=e^{i\kappa Arg(H_{k}^{H})} \tag{9}\]
## Appendix B Static Output-Feedback \(H_{\infty}\) Controller Design  
This appendix provides a brief summary of the static output-feedback \(H_{\infty}\) controller design methodology presented in [38; 39]. Let us consider the linear model  
\[\begin{cases}\dot{\mathbf{x}}(t)=\mathbf{A}\,\mathbf{x}(t)+\mathbf{B}\,\mathbf{ u}(t)+\mathbf{E}\,\mathbf{w}(t)\\ \mathbf{z}(t)=\mathbf{C}_{\text{z}}\,\mathbf{x}(t)+\mathbf{D}_{\text{z}}\, \mathbf{u}(t)\\ \mathbf{y}(t)=\mathbf{C}_{\text{y}}\mathbf{x}(t)\end{cases} \tag{12}\]  
where \(\mathbf{x}(t)\) is the state, \(\mathbf{u}(t)\) is the control action, \(\mathbf{w}(t)\) is the external disturbance, \(\mathbf{z}(t)\) is the controlled output, and \(\mathbf{y}(t)\) is the measured output. The design objective is to obtain an optimal static output-feedback \(H_{\infty}\) controller  
\[\mathbf{u}(t)=\mathbf{K}\mathbf{y}(t) \tag{13}\]  
that produces an asymptotically stable closed-loop matrix  
\[\mathbf{A}_{\text{K}}=\mathbf{A}+\mathbf{B}\mathbf{K}\mathbf{C}_{\text{y}} \tag{14}\]  
and, simultaneously, minimizes the associated \(H_{\infty}\)-norm\[\gamma_{{}_{\rm K}}=\sup_{\left\|{\bf w}\right\|_{2}\
eq 0}\frac{\left\|{\bf z} \right\|_{2}}{\left\|{\bf w}\right\|_{2}}, \tag{10}\]  
where \(\|{\bf f}\|_{2}=\left[\int_{0}^{\infty}{\bf f}^{T}(t)\,{\bf f}(t)\,dt\right]^{1/2}\) denotes the usual continuous 2-norm. Computing this kind of optimal controllers is a challenging problem that still remains open. However, according to the results in [38; 39], a suboptimal static output-feedback \(H_{\infty}\) controller  
\[{\bf u}(t)=\widetilde{\bf K}{\bf y}(t) \tag{11}\]  
can be computed by solving the following LMI optimization problem:  
\[\mathcal{P}:\left\{\begin{array}{l}\text{maximize }\eta\\ \text{subject to }{\bf X}_{\rm Q}>0,\,{\bf X}_{\rm  
\[\mathbf{T}_{\widetilde{K}}(s)=\mathbf{C}_{\widetilde{K}}(s\mathbf{I}-\mathbf{A}_{ \widetilde{K}})^{-1}\mathbf{E}, \tag{100}\]  
with  
\[\mathbf{A}_{\widetilde{K}}=\mathbf{A}+\mathbf{B}\widetilde{K}\mathbf{C}_{ \mathbf{y}},\quad\mathbf{C}_{\widetilde{K}}=\mathbf{C}_{\mathbf{z}}+\mathbf{D} _{\mathbf{z}}\widetilde{K}\mathbf{C}_{\mathbf{y}}, \tag{101}\]  
is the closed-loop transfer function from the disturbance input to the controlled output.
## 5 Simulation and Experiment Study
### Simulation Study
The output signal of FLS is shown in Figure 9a-c. Because of the FLS, it had more extensive and practical significance than CBC and PI controller in practical application without the need of model parameters, and its control performance was obviously better than them in practice. The adaptive disturbance estimation is shown in Figure 9d. The simulation verified the advanced nature of the designed controller. When the system parameters, model information and external disturbance could not be accurately obtained, the LIM could still track the reference speed precisely via the proposed PACFTB controller. In addition, the controller also kept the system in good working condition when there were unknown parameters and external disturbances.
# Numerical and Experimental Characterization of a Coanda-Type Industrial Air Amplifier
## 3 Experimental Setup
### Manufacturing and Assembly of the Venturi Tube  
The Venturi tube used to measure entrained flow adheres to the UNE-En ISO 5167 standard, with its key dimensions detailed in Figure 4. In accordance with these standards, it is required to establish a distance upstream from the constriction to ensure uniform and attached flow conditions. Consequently, a constant cross-section pipe was positioned upstream from the Venturi location. This section utilizes a methacrylate plastic tube, while the variable cross-sections are milled into Necuron, a high-density polyurethane material with excellent physical properties (see Figures 5 and 6).  
Two additional parts were custom-designed and computer numerical control (CNC)-milled in Necuron to properly fit the air amplifier up- or downstream from the Venturi, to evaluate the two different working configurations of the device. The operating setup of the blowing mode, where the air amplifier is located upstream from the Venturi tube, and the suction mode, where the device is placed downstream from the restriction, are depicted in Figure 7. Each additional part is attached to the tube only when fitting is required.  
Figure 4: Main dimensions of the Venturi tube (in mm).  
Figure 5: Assembly of the Venturi tube parts and methacrylate tube.  
The UNE-En ISO 5167 standard not only provides dimensions for the maximum wall angle or constriction distances but also provides specifications for the pressure tap diameter inside the Venturi tube constriction. As shown in Figure 8, larger diameter inserts were placed where the pressure tap would be located, ensuring proper measurement of the inner pressure in the tube.  
The final assembly was mounted on a rigid structure that kept the different parts aligned and in place throughout the experimental campaign, also facilitating the repositioning and adjustments needed on the air amplifier for the different analyses. Figure 9 shows a general view of the entire setup during the experiments.
# Formation Control Technology of Fixed-Wing UAV Swarm Based on Distributed Ad Hoc Network
###### Abstract  
The formation control technology of the unmanned aerial vehicle (UAV) swarm is a current research hotspot, and formation switching and formation obstacle avoidance are vital technologies. Aiming at the problem of formation control of fixed-wing UAVs in distributed ad hoc networks, this paper proposed a route-based formation switching and obstacle avoidance method. First, the consistency theory was used to design the UAV swarm formation control protocol. According to the agreement, the self-organized UAV swarm could obtain the formation waypoint according to the current position information, and then follow the corresponding rules to design the waypoint to fly around and arrive at the formation waypoint at the same time to achieve formation switching. Secondly, the formation of the obstacle avoidance channel was obtained by combining the geometric method and an intelligent path search algorithm. Then, the UAV swarm was divided into multiple smaller formations to achieve the formation obstacle avoidance. Finally, the abnormal conditions during the flight were handled. The simulation results showed that the formation control technology based on distributed ad hoc network was reliable and straightforward, easy to implement, robust in versatility, and helpful to deal with the communication anomalies and flight anomalies with variable topology.  
Keywords:fixed-wing UAV; UAV swarm formation; distributed ad hoc network; consistency theory; formation obstacle avoidance +
Footnote †: journal:  
Article
## 2 IoT in the Maritime Industry
### Current State of IoT Integration in the Maritime Sector  
The integration of IoT in the maritime sector is steadily progressing, driven by the need for digital transformation and the desire to improve efficiency, safety, and sustainability. Various stakeholders, including ship owners, operators, port authorities, and tech firms, are investing in IoT solutions to modernize their operations.  
'Smart shipping' is becoming increasingly prevalent, with modern vessels equipped with numerous sensors and devices to monitor their performance and condition. Real-time data from these sensors is utilized to enhance operational efficiency and safety. For instance, major shipping companies have started implementing IoT-based predictive maintenance systems to reduce downtime and operational costs [2, 7].  
Ports are also embracing IoT to transform into'smart ports.' Automated cranes, self-driving trucks, and IoT-based cargo handling systems are becoming common, improving efficiency and reducing the time ships spend in port.  
Additionally, IoT is being used to improve maritime safety and security. Vessel traffic management systems, piracy detection systems, and emergency response systems leveraging IoT technologies are being deployed to enhance maritime security [57, 58].  
However, while the benefits of IoT in the maritime sector are undeniable, several challenges need to be addressed for wider adoption. Data security and privacy concerns, high implementation costs, lack of interoperability, and the need for skilled personnel are among the significant hurdles. Despite these challenges, the trend towards digitization and the numerous benefits offered by IoT ensure its continued growth and integration in the maritime sector [50, 59].
# Geometric Accuracy Evaluation Method for Subway Stations Based on 3D Laser Scanning
## 3 Research Method  
### Overview  
The workflow of geometric accuracy evaluation using 3D laser scanning in this study is shown in Figure 1a. The methodology proposed in this study consists of four main steps (Figure 1b).  
Figure 1: (**a**) Workflow of geometric accuracy evaluation using 3D laser scanning; (**b**) data processing method.  
A coarse registration based on a grid is used to convert the point cloud to the survey coordinate system predefined in BIM;  
The point-to-line iterative closest point (PL-ICP) algorithm based on the inner wall lines is used to achieve fine registration;  
The structural elements of the subway station are extracted from the point cloud;  
The evaluation indexes are proposed and statistically analyzed for geometric accuracy evaluation.