esa-sceva/satcom-chunk-collection huggingface dataset:
# Measurement and Analysis on Magnetic Field Influence of Substation for Magnetic Shielding Device
## 5 Conclusions  
In order to reduce the influence of substations equipped with magnetic shielding devices on the shielding performance of magnetic shielding devices, the environmental magnetic field near commonly used substations is analyzed through simulation and experimental measurement methods, and its influence on magnetic shielding devices is analyzed. According to the analysis of the test results, the substation has an impact on both DC and AC magnetic fields. When using anything similar to substation 1 (323 kW), the magnetic shielding device should be at least 15 m away from the substation, and when using anything similar to substation 2 (1630 kW), the magnetic shielding device should be at least 60 m away from the substation. Therefore, when using something similar to substation 3 (9 kW), the magnetic shielding device should be at least 5 m away from the substation. The test results are in good agreement with the simulation results. This paper tests the DC magnetic field and magnetic field fluctuation of substations with common power in magnetic shielding devices, and the general formula of substations with different power is obtained for calculating the magnetic field value and distance, which provides a basis for the construction of magnetic shielding devices.  
**Author Contributions:** Conceptualization, Y.C. and R.S.; methodology, Y.C.; software, L.Z.; validation, Y.C. and Y.L.; formal analysis, Y.C.; investigation, Y.C.; resources, Y.C.; data curation, W.Z.; writing--original draft preparation, Y.C.; writing--review and editing, L.Z.; visualization, R.S.; supervision, R.S.; project administration, R.S. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Not applicable.  
**Conflicts of Interest:** The authors declare no conflict of interest.
# Full Information Numerical Simulation of Two-Dimensional Steady Ground Temperature Field
## 5 Accuracy Validation  
We designed a prism model with high thermal conductivity and compared the results of the algorithm in this paper with the calculation results of COMSOL Multiphysics finite element analysis software to verify the correctness of the algorithm.  
Figure 2: Flowchart of the algorithm.  
The high thermal conductivity prismatic model is shown in Figure 3. The background thermal conductivity is \(2\,\mathrm{W}/(\mathrm{m}\cdot\mathrm{{}^{\circ}C})\), with no radiogenic heat production. There are prism anomalies with a side length of 2 km at the center of the calculated region, and the anomalous thermal conductivity is \(6\,\mathrm{W}/(\mathrm{m}\cdot\mathrm{{}^{\circ}C})\). The calculation region of the model is \(-5\)-\(5\) km in the x direction and \(0\)-\(10\) km in the z direction. The first type of boundary condition is used for the upper boundary; the temperature is \(10\,\mathrm{{}^{\circ}C}\). The lower boundary also adopts the first kind of boundary condition; the temperature is \(164\,\mathrm{{}^{\circ}C}\). The grid nodes are \(101\,\times\,101\). Figure 4 presents the computational results of the proposed algorithm (a) and COMSOL Multiphysics (b) for the model shown in Figure 3, along with the relative error of the proposed algorithm's results compared to those of COMSOL Multiphysics (c). From the relative error distribution map (Figure 4c), it can be observed that the maximum relative error between the computational results of the proposed algorithm and those of COMSOL Multiphysics for the model in Figure 3 does not exceed \(0.5\%\), confirming the accuracy and correctness of the proposed algorithm.
# Space Debris In-Orbit Detection with Commercial LiDAR Sensors
## 1 Introduction
As a result, LiDARs generally have much higher temporal and spatial resolutions and smaller instrument sizes [18]. Unlike ground-based tools, LiDAR systems on satellites are not hindered by atmospheric conditions [19], offering a more effective and direct means of monitoring space debris. LiDAR was first used primarily in aerospace and topographic applications because of its high cost and size. With the rise of autonomous vehicle technology, LiDAR has gained importance in providing vehicles with a 3D perception of the environment [20]. Efforts have been made to miniaturize LiDAR components to make them more streamlined and aesthetically acceptable in vehicles. The evolution of LiDAR systems in the automotive field is continuously progressing, with significant advances in miniaturization, costs, and technical capabilities.
## 3 The Challenges and Limitations of Large Language Models Across Various Domains of Everyday Life
### Agriculture
#### 3.5.1 Lack of Visual Data for Training CV with LLMs  
One of the fundamental challenges in employing large multimodal language models in agriculture is the lack of high-quality and sufficiently diverse visual data for effective training of computer vision (CV) models. Many agricultural applications, such as plant disease detection, crop quality assessment, or weed identification, require accurate, diverse, and well-labeled image data [114]. However, collecting such data in agriculture is costly and time-consuming, and demands domain-specific expertise, as the images must be captured and labeled under various lighting, climatic, and biological conditions. This issue is particularly pronounced in less developed regions, where infrastructure for data collection and archiving is limited [112]. As a result, CV models trained on insufficient or imbalanced data suffer in terms of accuracy, generalizability, and performance stability. To overcome this challenge, the use of multimodal language models such as DALL-E or Flamingo has been proposed for synthetic generation of visual data. These models can produce artificial images based on textual descriptions of agricultural phenomena and enhance CV model performance by increasing diversity in training datasets [110]. However, synthetic data generation also faces challenges such as fidelity to reality, quality preservation, and the need for human evaluation.
## 2 Mechanical Characterisation and Selection of Base Materials
### Alkali-Resistant Glass Fabrics
subjected to the tensile load \(P\); as one should note, \(A_{f}\) does not correspond to the product between the equivalent thickness \(t_{eq}\) and 70 mm, since the strip width \begin{table}
\begin{tabular}{l l c c c c c c c} \hline \hline  & **F1** & **F2** & **F3** & **F4** & **F5** & **F6** & **F7** \\ \hline \multirow{3}{*}{Fabrication technique} & Leano & Double & Double & Double & Double & Double & Leano & Leano \\  & weave & leano & leano & leano & leano & leano & weave & weave \\ Coating nature & & & weave & weave & weave & weave & & \\  & SRR & Epoxy & & SRR & Epoxy & SRR & & \\ \hline \multirow{3}{*}{Warp} & Wire spacing (mm) & 18 & 38 & 38 & 38 & 38 & 5 & 10 \\  & Roving fineness (Tex) & 2 \(\times\) 1200 & 2 \(\times\) 1200 & 2 \(\times\) 1200 & 2 \(\times\) 2400 & 2 \(\times\) 2400 & 2 \(\times\) 1200 & 2 \(\times\) 2400 \\  & Filament diameter (\(\mu\)m) & 19 & 19 & 19 & 27 & 27 & 19 & 27 \\  & Equivalent reinforcement & & & & & & & \\  & thickness\({}^{*}\)\(t_{eq}\) (mm) & 0.050 & 0.046 & 0.046 & 0.093 & 0.093 & 0.179 & 0.179 \\ \hline \multirow{3}{*}{Wert} & Wire spacing (mm) & 18 & 38 & 38 & 38 & 38 & 12 & 14.3 \\  & Roving fineness (Tex) & 2400 & 2 \(\times\) 2400 & 2 \(\times\) 2400 & 4 \(\times\) 2400 & 2400 & 2 \(\times\) 1200 \\  & Filament diameter (\(\mu\)m) & 27 & 27 & 27 & 27 & 27 & 19 \\  & Equivalent reinforcement & & & & & & \\  & thickness\({}^{*}\)\(t_{eq}\) (mm) & & & & & & & \\ \hline \hline \end{tabular}  
* * calculated over a width of 1 m.  
\end{table} 
Table 4: Alkali-resistant glass fabrics characteristics. Figure 2: Fabric and textile reinforced concrete (TRC) specimens: uniaxial tensile test setups and nominal geometries (measures expressed in mm). was generally not an exact multiple of the grid spacing. The fabric efficiency factor \(EF_{f}\) was instead calculated as follows:  
\[EF_{f}=\frac{P_{f,max,avg}}{A_{f}\cdot\sigma_{fu}}\, \tag{2}\]  
where \(\sigma_{fu}\) is the glass filament strength, assumed equal to 2000 MPa according to the manufacturer data. The parameter \(EF_{f}\) provides crucial information on the rate of utilisation of the reinforcing material and may hence be related to cost-efficiency considerations. As an example, despite Fabric F4 being characterised by a 43% smaller \(A_{f}\) than Fabric F7 (warp direction), the average peak loads were nearly the same, meaning that in Fabric F7 several glass filaments were basically ineffective. This was explained by the greater capability of epoxy resin to impregnate the glass filaments, limiting telescopic failure modes [21]. Average load vs. stroke displacement (\(P\)-\(\delta\)) and nominal fabric stress vs. normalised displacement (\(\sigma_{f}\)-\(\delta\)/\(L_{0}\)) curves are plotted in Figures 3 and 4, respectively; the nominal fabric stress \(\sigma_{f}\) was calculated as \(P_{f,max,avg}/A_{f}\), while the normalised displacement was obtained as the ratio between the stroke displacement and the free specimen length of Figure 2 (about
## 4 Classification of Energy Efficient MAC Protocols for UWSNs
### Bandwidth  
Based on geographical, spatial and temporal uncertainty, narrow bandwidth, near and distant field communication issues, time synchronization, and throughput performance variations. Frequency domain for MAC protocols is not the first choice of communication technique to be used for UWSNs [98]. The bandwidth MAC protocols, on the other hand, have access to the entire bandwidth of the connection channel and can distribute network resources on demand. As a result, the majority of the work on MAC protocols for UWSNs has been focused on bandwidth domain MAC protocols [99]. Table 6 shows, the significant differences between the frequency domain and bandwidth MAC protocol.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Factors** & **Frequency Dominion** & **Bandwidth** \\ \hline Scheduling & Central & Spread \\ Channel usage & Low & High \\ Network resource sharing & Reserved for a certain user & On demand \\ Appropriate network load & Low & High \\ Appropriate node density & Low & High \\ Appropriate network size & Small & Big \\ Ratio of collision & Low & High \\ Throughput & Low & High \\ Energy consumption & Low & High \\ Propagation delay & High & Low \\ \hline \hline \end{tabular}
\end{table}
Table 6: The evaluation among frequency dominion and bandwidth MAC protocols.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Protocol** & **Collision Rat** & **Network Topology** & \begin{tabular}{c} **Simultaneous** \\ **Transmission** \\ \end{tabular} & **Throughput** & \
\begin{tabular}{c} **Power** \\ **Consumption** \\ \end{tabular} &
\begin{tabular}{c} **Propagation** \\ **Delay** \\ \end{tabular} \\ \hline UAMC-MAC & Medium & Ad-hoc, stationary & Yes, during one & & & \\  & & & & & High \\ ERCA-MAC & Low & Cluster, stationary & No & Medium & Low & Medium \\ \hline P-MAC & High & Ad-hoc, stationary & Yes & High & High & Low \\ H-MAC & Medium & Ad-hoc, stationary & Yes & High & Low & Low \\ \hline \hline \end{tabular}
\end{table}
Table 5: Cross correlation between UAMC-MAC, ERCA-MAC, P-MAC and H-MAC protocols.
# Feasibility of Developing Sustainable Concrete Using Environmentally Friendly Coarse Aggregate
## 5 Conclusions  
A systematic laboratory experimental investigation has been conducted to assess the feasibility of using manufactured RCA in concrete as an alternative for quarried coarse aggregate. The following conclusions can be drawn based on the material properties of RCA concrete:  
* Compressive strength of combined RCA-25 and combined RCA-40 concretes increased from 19.29-44.50 MPa and 36.75-60.70 MPa from 7 to 90 days, respectively. This satisfied the specified 28-day design strength of exposure categories, A1/A2 (20/25 MPa) and B1/B2 (32/40 MPa) stated in Australian standards, AS3600.
* Aggregate grading of manufactured RCA matched with quarried aggregate increased the compressive strength of RCA concrete. This is due to aggregate packing density having a significant role in strength development.
* Both combined RCA-25 and combined RCA-40 concretes displayed comparable tensile strength and elastic modulus to an equivalent quarried coarse aggregate concrete of the same compressive strength. Experimentally observed flexural strength, splitting tensile strength, and elastic modulus are higher than the estimated values based on stated design equations in AS 3600, confirming that Australian standards can be used for the conservative design.
* Low water absorption coupled with high ultrasonic pulse velocity demonstrate that combined RCA concretes contain a dense microstructure and pore-structure free of large voids or cracks. This would be expected to prevent ingress of aggressive materials. The rough fracture surface of aggregate increased the bond between C-S-H gel matrix and RCA at ITZ.
* Combined RCA concretes display low drying shrinkage which is significantly lower than the maximum permitted value recommended by Australian standard.  
Overall, this innovative and sustainable recycle product has significant potential as a coarse aggregate in concrete, with the substantial additional benefit of recycling wet concrete while minimizing environmental impact due to landfilling.  
Conceptualization, C.G.; Methodology, C.G. and D.W.L and S.S.; Software, C.G.; Data curation, C.G. and C.S.; Validation. C.G. and C.S.; Formal analysis, C.G. and C.S.; Investigation, C.G.; Writing--original draft, C.G.; Project administration, C.G.; Writing--review & editing, C.S. and D.W.L and S.S.; Supervision, D.W.L. and S.S.; Funding acquisition, D.W.L. and S.S. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The authors wish to acknowledge Cycrete Pty Ltd. for the supply of recycled coarse aggregates. The X-ray facility and Microscopy & Microanalysis facility provided by RMIT University is also acknowledged. This research was conducted by the Australian Research Council Industrial Transformation Research Hub for nanoscience-based construction material manufacturing (IH15010006) and funded by the Australian Government.  
The authors declare that they have no conflict of interest.
###### Abstract  
The rapid growth in large-scale distributed video conferencing, remote education, and real-time broadcasting poses significant challenges to traditional centralized streaming systems, particularly regarding scalability, cost, and reliability under high concurrency. Centralized approaches often encounter bottlenecks, increased bandwidth expenses, and diminished fault tolerance. This paper proposes a novel decentralized real-time broadcasting system employing a peer-to-peer (P2P) chain topology based on IPv6 networking and the Secure Reliable Transport (SRT) protocol. By exploiting the global addressing capability of IPv6, our solution simplifies direct node interconnections, effectively eliminating complexities associated with Network Address Translation (NAT). Furthermore, we introduce an innovative chain-relay transmission method combined with distributed node management strategies, substantially reducing reliance on central servers and minimizing deployment complexity. Leveraging SRT's low-latency UDP transmission, packet retransmission, congestion control, and AES-128/256 encryption, the proposed system ensures robust security and high video stream quality across wide-area networks. Additionally, a WebSocket-based real-time fault detection algorithm coupled with a rapid fallback self-healing mechanism is developed, enabling millisecond-level fault detection and swift restoration of disrupted links. Extensive performance evaluations using Video Multi-Resolution Fidelity (VMRF) metrics across geographically diverse and heterogeneous environments confirm significant performance gains. Specifically, our approach achieves substantial improvements in latency, video quality stability, and fault tolerance over existing P2P methods, along with over tenfold enhancements in frame rates compared with conventional RTMP-based solutions, thereby demonstrating its efficacy, scalability, and cost-effectiveness for real-time video streaming applications.  
decentralized video broadcasting; real-time streaming; SRT protocol; IPv6 network; chain topology; intelligent self-healing; fault tolerance; low-latency transmission; distributed systems; peer-to-peer architecture
# Wireless Mesh Networking: An IoT-Oriented Perspective Survey on Relevant Technologies
## 5 Mesh Networking with IEEE 802.15.4
### Applications: Comparison between ZigBee Pro and LWMesh Protocols
#### 5.3.2 Routing Latency  
In [73], the latency in multi-hop communications among nodes is evaluated measuring the traffic time among two routing nodes, sending over 30,000 packets in a topology composed by four nodes. Although the difference, in terms of routing latency, between ZigBee Pro and LWMesh is little, the obtained results show that, for LWMesh, the forward latency is affected in small part by the introduction of security measures (even considering the adoption of AODV in ZigBee Pro). Moreover, the intermediate routing nodes forward packets at L3, thus achieving higher throughput than end nodes, not processing packets up to the application layer. Finally, with respect to forwarding, the end-to-end processing affects the throughput in ZigBee-based scenarios, while it reduces in small part for not secured option in LWMesh-based scenarios. On the other hand, the use of encryption reduces, as expected, the application throughput in LWMesh.
# Analysis of Sentinel-1 Radiometric Stability and Quality for Land Surface Applications
## 3 Data Analysis  
For each S-1A image, the values of all pixels within each invariant target were averaged to determine the mean backscattering coefficients (\(\sigma^{\circ}\)). \(\sigma^{\circ}\)-values were then converted into dB units.
# Feasibility Study and Prospects of Rock Fragmentation Using Ultrasonic Vibration Excitation
## 3 The Theoretical Feasibility of Ultrasonic Rock Breakage  
The natural frequency of rock is above 7-20 kHz, and similarly the ultrasonic frequency is above 20 kHz. Therefore, the ultrasonic technology is introduced into the hard rock fragmentation. By adjusting the ultrasonic frequency to approximate the natural frequency of the rock, the method can cause the rock to vibrate, and stimulate the fracture imitation and propagation so as to improve the rock breakage efficiency.  
The use ultrasonic technology in rock breakage has been examined in the 1950s, by the former Soviet Union [PERSON]. They focused on the ultrasonic mechanical effects, cavitation, and the mixture of these two aspects. The technical requirements for rock breakage by ultrasonic waves were advanced theoretically. Of note is that due to the limitations on the research conditions at that time, there was no huge progress in that research. With the improved understanding of the role of ultrasound and the continuous development of large-scale ultrasonic generator manufacturing technology in recent decades, the mechanism of using ultrasonic waves on rock mechanics is becoming clearer, and using ultrasonic waves for rock breakage is becoming a promising option.
# Ultraviolet Transient Absorption Spectrometer with Sub-20-fs Time Resolution
## UV Pulse Generation and Characterization
### Pulse Generation
The phase-matching bandwidth can be considerably increased by the use of achromatic phase matching [48; 49], in which the broadband pulses are angularly dispersed so that each frequency propagates within the nonlinear crystal at its own phase matching angle. Employing achromatic SHG, [PERSON] et al. [50; 51] frequency doubled the output of a broadband visible NOPA in a 360-um-thick BBO crystal, obtaining pulses with energy in excess of 200 nJ and 250 THz bandwidth. [PERSON] et al. produced sub-15-fs pulses with 600-nJ energy by achromatic sum-frequency generation (SFG) of the NOPA output with the FW of Ti:sapphire [52]. The advantage of achromatic phase matching, however, comes at the cost of a considerable complication of the experimental apparatus. The phase-matching requirements are less tight for SFG between a narrowband pulse at frequency \(\omega_{1}\) and a broadband pulse at frequency \(\omega_{2}\), to give \(\omega_{3}=\omega_{1}+\omega_{2}\). For this configuration, the phase-matching bandwidth becomes [53]\(\Delta v_{SFG}~{}=~{}0.886/|\delta_{32}|L\), where \(\delta_{32}~{}=~{}\frac{1}{v_{g3}}-\frac{1}{v_{g2}}\) is the GVM between the broadband pulse and the SFG pulse. For the case of BBO with Type II (oe) phase matching, considering up-conversion of a visible pulse by a narrowband pulse centered at \(\lambda_{1}\) = 800 nm, one gets \(\delta_{23}\) = 120 fs/mm; this means that a relatively thick 50-um BBO crystal can be used to up-convert a sub-10-fs visible pulse to the UV. Using this configuration, [PERSON] et al. generated 8 fs pulses with 1-uJ energy and central wavelength tunable from 310 to 400 nm by SFG between the NOPA output and a narrowband NIR pulse, generated either directly by Ti:sapphire or by an OPA [53].
_Appl. Sci._**2014**, \(4\), 498-514; doi:10.3390/app4040498  
_Applied sciences_  
**ISSN 2076-3417**  
www.mdpi.com/journal/applsci  
_Article_  
**Continuous-Wave Molecular Modulation Using a High-Finesse Cavity**  
**[PERSON], [PERSON] and [PERSON] ***  
Department of Physics, University of Wisconsin at Madison, 1150 University Avenue,  
Madison, WI 53706, USA; E-Mails: [EMAIL_ADDRESS] (D.C.G.); [EMAIL_ADDRESS] (J.J.W.)  
* Author to whom correspondence should be addressed; E-Mail: [EMAIL_ADDRESS];  
Tel.: +1-608-263-9399.  
External Editor: [PERSON]  
_Received: 26 September 2014; in revised form: 5 November 2014 / Accepted: 10 November 2014 / Published: 18 November 2014_  
**Abstract:** We demonstrate an optical modulator at a frequency of 90 THz that has the capability to modulate any laser beam in the optical region of the spectrum. The modulator is constructed by placing deuterium molecules inside a high-finesse cavity and driving a vibrational transition with two continuous-wave laser beams. The two beams, the pump and the Stokes, are resonant with the cavity. The high intra-cavity intensities that build up drive the molecules to a coherent state. This molecular coherence can then be used to modulate an independent laser beam, to produce frequency up-shifted and down-shifted sidebands. The beam to be modulated is not resonant with the cavity and thus the sidebands are produced in a single pass.  
**Keywords:** stimulated Raman scattering; Raman lasing; optical modulators; ultrafast physics; subfemtosecond pulses