esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Geomagnetic Activity and Ionospheric Weather
### Variation of TEC Measurements
Probably this negative excursion can be considered a signature of the ionospheric precursor of EQ, but the exact origin of this reduction is difficult to locate. Even though in the following analysis we avoid subtracting the level of reference (instead we consider the difference between Ne from the two satellites flying side by side, thus the ionospheric background is removed automatically), careful examination of the  
Figure 4: GIM-TEC distribution in the latitudinal range 0\({}^{\circ}\)–70\({}^{\circ}\)N at 18 UT (first row) and 23 UT (second row) for (**a**,**d**) January 21, (**b**,**e**) January 22, (**c**,**f**) January 23. The epicenter of EQ is shown as a white dot in panels (**b**,**e**). The color bar shows TEC is in TECU. Figure 5: TEC values (**a**) averaged over the Northern Hemisphere (0\({}^{\circ}\)–70\({}^{\circ}\)N) and (**b**) at a grid point 40\({}^{\circ}\)N, 80\({}^{\circ}\)E for the period of 21–23 January. The EQ time is indicated by the black triangle on the x-axes. Note the logarithmic scale in panel (**b**). Red (blue) vertical lines mark the time of the descending (ascending) orbit of the satellite when it passed near the epicenter. ionospheric weather before searching for coseismic anomalies is important. Otherwise, the short-term response of the ionosphere, even to a relatively minor change in the solar radiation flux, can be unreasonably interpreted as a coseismic anomaly.
## 4 Research Methodology
### Selection of Simulation Parameters
#### 4.2.2 Selection of Catchment Points  
Catchment points represent the initiation points for simulated mudslides, assuming that mudslide events originate from these specific locations. These points are typically situated in areas with dense material sources and favorable conditions for rainwater accumulation. Such locations provide increased gravitational potential energy for mudslide initiation, which is subsequently converted into kinetic energy during mudslide movement [31]. Consequently, catchment points are predominantly located at the interface between the source area and the transportation zone. Figure 5 illustrates the selected catchment point locations based on this rationale. Due to the short lengths of other minor tributary gullies, the establishment of catchment points within them was deemed unnecessary.  
Figure 5: Location map of catchment points in Dashiling Gully.
# Preliminary Validation of Surface Reflections from Fengyun-3C Radio Occultation Data
## 2 Data and Quality Control
### FY-3C RO Data  
FY-3C has the capability to observe the phase and amplitude measurements from GPS and BDS satellites as they are occulted by Earth's atmosphere, and these raw data are defined as the Level-0 data [32]. Based on the highly accurate LEO precise orbit determination (POD) data and occultation observations (Level-0), the calculation program was run to determine excess phase data (Level-1). The bending angle profiles were retrieved by Geometric Optics (GO) and Wave Optics (WO) methods at different altitudes [2; 24], then the refractivity profiles were retrieved through Abel transforming based on the optimized bending angle profiles (Level-2) [32]. In this paper, the FY-3C raw data measurements of Level-1 and refractivity profiles of Level-2 during 2015 were used for in-depth analysis.
# Energy and Delay Aware Data Aggregation in Routing Protocol for Internet of Things
## 6 Result and Discussions
### Simulation Results
#### 6.2.4 Packet Loss Ratio with Presence of Failed Node Scenario  
Figure 8 depicts the packet loss ratio for the failed node scenario. It is noted that RPL, LA-RPL and EDADA-RPL's packet loss ratiosare 25%, 18%, and 12%, respectively, while the node size failed is 50. It is also found that, as the number of failed node size decreases, the packet loss increases.It is due to the lack of neighbor nodes, coverage issues, and difficultyin finding alternate nodes. Nevertheless, the EDADA-RPL identifies an alternative node to immediately transfer data to the DODAG root.  
Figure 6: Average number of parent change vs. various RPLs.  
Figure 7: Number of hop count vs. Network size.
# Dynamic Responses Measured by Optical Fiber Sensor for Structural Health Monitoring
## 4 Shock and Vibration Tests
### Base Excitation
#### 4.1.1 Single Frequency Base Excitation  
The cantilever beam is excited by a shaker with a frequency of 7 Hz, which is approximate to the first natural frequency of 7.37 Hz. An FBG sensor is attached at the center of the cantilever beam. Once the light intensity reflected from the FBG sensor has been measured, we then extract the strain using Equation (5). The strain measured by the FBG sensor is compared with the result of strain gauge as shown in Figure 8. It shows that a good agreement is achieved with an average difference of 3.7%. The same experimental test was conducted by [PERSON] and [PERSON] [43]. The vibrational response was measured using a Mach-Zehnder interferometric optical sensor, as shown in Figure 9. It can be observed that a reasonable agreement is obtained between the FBG sensor and Mach-Zehnder interferometric optical sensor.  
Figure 8: Vibrational response of a cantilever beam subjected to single frequency base excitation.  
Figure 7: Base excitation test on a cantilever beam. (**a**) schematic diagram; (**b**) experimental setup.
# Guard Band Protection Scheme to Facilitate Coexistence of 5G Base Stations and Radar Altimeters
###### Abstract  
Reformation of the 3.7-4.0 GHz band to expand 5G communication deployment poses a risk of 5G signals disrupting radar altimeter operation, leading to data loss or inaccuracies. Thus, this paper proposes a guard band protection method to facilitate the coexistence of 5G base stations and radar altimeters operating in the 4.2-4.4 GHz band. To enhance the adjacent channel leakage ratio (ACLR), we implemented spectral regrowth on an oversampled waveform using a high-power amplifier model, filtering out-of-band spectral emissions. The results demonstrated that a 150 MHz guard band enables coexistence, except in the case of the 16-by-16 antenna array in rural environments. Notably, for the 4-by-4 antenna array in urban environments, coexistence can be achieved using a 50 MHz guard band. The proposed mitigation techniques may also be extended to promote coexistence between non-terrestrial networks and 5G communication systems, including satellites, unmanned aerial vehicles, and hot air balloons.  
5G base station; radar altimeter; coexistence; guard band; radio interference; non-terrestrial network +
Footnote †: journal: Electronics Letters
# Smart Grid Protection, Automation and Control: Challenges and Opportunities
## 5 Redundancy
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**System** & **Description** & **Advantages** & **Disadvantages** & **Application** \\ \hline \multirow{4}{*}{System 1} & Two CPAC units to eliminate loss of protection if one CPAC fails. Only one Merging Unit (MU) per protected circuit. & High availability of protection in case one CPAC unit fails. & If the MU fails, the specific circuit will be unprotected. & Users rely on a single multifunction relay per circuit in a conventional setup. \\ \hline \multirow{4}{*}{System 2} & One CPAC unit and a multifunction relay or Intelligent Merging Unit (MU) per circuit can act as an MU. & The IMU provides protection if the CPAC unit fails. & If the IMU fails, the circuit where it was used will be unprotected. & Users with multifunction relays capable of acting as merging units are looking to add new functions or backup protection. \\ \hline \multirow{4}{*}{System 3} & Two MUs per protected circuit to eliminate a single point of failure. & No system failure will compromise protection. & The number of circuits protected by the CPAC unit is halved. & Clusters aim to avoid a single point of failure and provide all protection and control functions at the CPAC level. \\ \hline \multirow{4}{*}{System 4} & Two CPAC units for the entire system, one MU and one IMU per protected circuit. & High reliability: the failure of both CPACs and an MU or MU leaves no circuit unprotected. & The system’s complexity increase due to the integration of multiple components, necessitating rigorous management and expertise to ensure seamless operation and coordination. & Users seeking the highest levels of reliability. \\ \hline \multirow{4}{*}{System 5} & One CPAC unit for the entire system, one MU and one IMU per protected circuit. & Avoids a single point of failure by adding an IMU; the system is protected even if the CPAC, MU, or IMU fails. & The number of circuits protected by the CPAC unit is halved. & Users with microprocessor relays that can act as merging units and wish to add additional functions or backup protection without a single point of failure. \\ \hline \hline \end{tabular}
\end{table} 
Table 21: Different redundant systems for a CPAC system.
# Laser Intensity Noise Suppression for Preparing Audio-Frequency Squeezed Vacuum State of Light
## 1 Introduction
Similarly, in our detection system, as the intensity noise of LO is higher than the SNL, and the CMRR of BHD is limited (\(\sim\)35 dB), the output squeezing level of OPO/OPA cannot be detected accurately. There are two ways to improve the accuracy of the squeezing level, one is to increase BHD's CMRR to cancel out the relative intensity noise of LO higher than the SNL in the audio frequency range, which is difficult to achieve due to the technical and electronic circuit barriers; the other is to suppress the relative intensity noise of LO, which makes it possible for BHD to offset the common-mode noise and easier for us to implement.
## 3 Results and Discussion
### Single Carbon Fiber Tensile Strength Measurements  
Single fiber tensile strength tests were carried out to investigate the effect of laser irradiation on the CFs' tensile properties (Figure 9). Every specimen's gauge length was chosen at 20 mm, following the methodology described in Section 2.5. Tensile strength values were calculated using Equation (1). The tensile strengths of non-exposed CFs bTCF and bPCF were estimated as \(3.2\pm 0.32\) GPa and \(3.19\pm 0.36\) GPa respectively. For the range of investigated fluences (37-47 J/cm\({}^{2}\); power: 3.75-4.75 W), a decrease up to 61% was observed on the tensile strength of the irradiated CFs (\(2.14-1.25\pm 0.38\) GPa), when compared to reference CFs (bTCF and bPCF) (Table 2). It can be assumed that the deterioration of the CFs' tensile strength, was caused by the high temperatures, that were generated by the CO\({}_{2}\) photothermal effect. By definition, fluence is the energy delivered by the laser beam per unit area, which means that when the fluence was increased to higher levels, the induced thermal loading on CFs increased as well, causing greater deterioration of the CFs' tensile strength. However, even at low fluences, the thermal loading was high enough to impose harmful effects to the mechanical integrity of them. PCF\({}_{4.25\,\mathrm{W}}\) displayed a lower decrement in the tensile strength (\(-33\%\)) compared to TCF\({}_{4.25\,\mathrm{W}}\) (\(-58\%\)), and this can be attributed to the different turbostatic nature of the original non-exposed fibers; however, the Raman I\({}_{\mathrm{D}}\)/I\({}_{\mathrm{G}}\) did not show any significant difference (bTCF: 0.85; bPCF: 0.88). SEM analysis revealed that bTCF (Figure 6a,b, Figure S9) possessed an extremely smooth surface when compared to bPCF (Figure 6m,n, Figure S15), where graphitic stripes were observed (originating from the drawing process of the fiber).  
Figure 8: Fluence vs I\({}_{\mathrm{D}}\)/I\({}_{\mathrm{G}}\) intensity ratio of the irradiated samples.
## 5 Disscussion
### Petrogenesis of LG
#### 5.2.2. _M_agmatic Origin  
LG has \(\epsilon_{\rm Hf}\)(t) values ranging from \(-14.97\) to \(-7.59\) with an average and a peak around \(-10\) and two-stage model ages (T\({}_{\rm DM2}\)) ranging from 2939 to 2280 Ma with an average and a peak around 2500 Ma (Figure 11), indicating that the contribution of the crustal source to the magma is dominant. As a comparison, late Jurassic Laiziling granite in the XHLOF has higher \(\epsilon_{\rm Hf}\)(t) values (\(-4.2\) on average) and smaller T\({}_{\rm DM2}\) (1.47 Ga on average), which reflects the obvious addition of mantle-derived materials [29]. However, the effect of mantle-derived heat on the magma origin of LG is significant, which can be reflected by a  
Figure 10: Triangle diagrams for distinguishing group A\({}_{1}\) and group A\({}_{2}\) granitoids.  
magma temperature as high as 971 \({}^{\circ}\)C on average presented by the zircon Ti thermometer (Supplementary Table S2).  
The source of A\({}_{2}\)-type granitoids was believed to originate from subduction or continental collision [48]. The abundant occurrence of \(\sim\)2.5 Ga detrital zircon indicates that \(\sim\)2.5 Ga, consistent with the T\({}_{\text{DM2}}\) age of LG, is an important period for the crustal growth of Cathaysia block [59]. Subduction and collision zones are the main sites for the formation of the juvenile crust [60], which indicates that the source of LG may originate from the subduction or collision zones during \(\sim\)2.5 Ga. The source discriminant diagram indicates that tonalites and metasediments are the potential sources of LG (Figure 12, [61]). The tonalites are the main component of the TTG, which was the main component of the juvenile crust in the subduction and collision zones and dominated early continental crust [62]. Metasediments could originate from the weathering products of TTG. In addition, the strong depletion of Eu and the enrichment of heavy rare earths indicate that the magma source area is in a stable condition with a large amount of plagioclase and no garnet.  
Figure 12: Temary diagram for distinguishing the potential sources of granite.  
Therefore, we believe that LG originated from partial melting of reworked ancient crust, which consisted of TTGs, and its weathered sediments formed in subduction or collision zones at 2.5 Ga and partial melting might have been caused by the mantle-derived magma beneath the lithosphere in an extensional tectonic setting.
# A Review of Time-Scale Modification of Music Signals +
## 4 TSM Based on Waveform Similarity Overlap-Add (WSOLA)
### Artifacts  
WSOLA can improve on some of the drawbacks of OLA as illustrated by Figure 6 (WSOLA) and Figure 4 (OLA). However, it still causes certain artifacts that are characteristic for time-domain TSM procedures.  
A prominent problem with WSOLA-like methods is known as _transient doubling_ or _stuttering_. This artifact is visualized in Figure 7, where we can see a single transient in the input signal \(x\) that is contained in the overlapping region of two successive adjusted analysis frames \(x^{\prime}_{m}\) and \(x^{\prime}_{m+1}\). When the frames are relocated and copied to the output signal, the transient is duplicated and can be heard two times in quick succession. A related artifact is _transient skipping_ where transients get lost in the modification process since they are not contained in any of the analysis frames. While transient doubling commonly occurs when stretching a signal (\(\alpha>1\)), transient skipping usually happens when the signal is compressed (\(\alpha<1\)). These artifacts are particularly noticeable when modifying signals with percussive components, such as recordings of instruments with strong onsets (e.g., drums, piano).  
Furthermore, WSOLA has particular problems when modifying polyphonic input signals such as recordings of orchestral music. For these input signals, the output often still contains considerable warbling. The reason for this is that WSOLA can, by design, only preserve the most prominent periodic pattern in the input signal's waveform. Therefore, when modifying recordings with multiple harmonic sound sources, only the sound of the most dominant source is preserved in the output, whereas  
Figure 6: Preservation of periodic structures by WSOLA. The input signal \(x\) is the same as in Figure 4, this time modified with WSOLA (time-stretch with \(\alpha=1.8\)).  
Figure 7: Transient doubling artifact as it typically occurs in signals modified with WSOLA.  
the remaining sources can still cause phase jump artifacts. While WSOLA is well-suited to modify monophonic input signals, this is often not the case with more complex audio.
# CUDA-Optimized GPU Acceleration of 3 GPP 3D Channel Model Simulations for 5G Network Planning
## 4 GPU-Based Acceleration Using NVIDIA CUDA
### Shared Memory  
Shared memory is an on-chip memory with low latency and very high bandwidth (similar to an L1 cache), local to each streaming multiprocessor and accessible only by threads in the same block. Developers must explicitly specify shared memory data, using the __shared__ storage attribute to allocate arrays in shared memory, and move data between global and shared memory using kernel code. In our work, threads compute the channel response for each transmitter-receiver antenna port in a cluster and require repeated reading of the input data (1). Because the CUDA global memory is not fast enough to provide data to all processing elements, a two-step loading mechanism is used. First, the input data are loaded into the on-chip shared memory in a coalesced fashion, and then the data are accessed for CIR computation.
# A Review of Early Injection Strategy in Premixed Combustion Engines
## 7 Future Research Directions  
From the review of the published work on the early injection parameters of HCCI and PCCI engines, the following interesting topics are identified for investigation in future research:  
* Methods to limit or avoid the wall-wetting problem caused by early injection strategy, including improved injection system or multiple-pulse injection strategy.
* Accurate spray-wall impingement mechanism, especially the fuel, including alternative fuel, because the physical and chemical characteristics changed with the addition of alternative fuel.
* The effect of the impingement target on mixture formation and emission distribution in the cylinder; in addition, optimization of the impingement target should consider the factors of injection timing, injection angle, and piston structures simultaneously.
* The effects of the early injection parameters on combustion noise radiation, which is expected to gain interest with the development of HCCI and PCCI engines.
* The interrelationship between early injection strategy and modern catalytic devices, such as Diesel Particulate Filter (DPF), Selective Catalytic Reduction (SCR), and Lean NOx Trap (LNT), especially with respect to particle number concentration and distribution, but also possibly due to durability issues.
* Early injection strategy combined with reactivity controlled compression ignition (RCCI), research and analysis of the impact of early injection strategy on RCCI engine, including injection timing, injection pressure, injection angle and so on.
* Combining different types of lubricating oils, one can study the influence of early injection strategies on engine performance and emission characteristics.  
**Author Contributions:** [PERSON] and [PERSON] researched the literatures. [PERSON] and [PERSON] analyzed and discussed the results. [PERSON] and [PERSON] provided the future research direction. [PERSON] and [PERSON] wrote the paper. [PERSON] and [PERSON] edited the paper.  
**Funding:** This research was funded by the National Natural Science Foundation of China, grant number 91641111, 51976135 and 51806148. The author also wants to appreciate the support of Marine Low-Speed Engine Project (Phase I) of MIIT.  
**Conflicts of Interest:** The authors declare no conflict of interest.  
**Nomenclature**  
HCCI homogeneous charge compression ignition  
PCCI premixed charge compression ignition  
RCCI reactivity controlled compression ignition  
NOx nitrogen oxides  
EGR exhaust gas recycling  
TDC top dead center  
BTDC before top dead center  
CO carbon monoxide  
HC hydrocarbon  
DME dimethyl ether  
IMEP indicated mean effective pressure  
DI direct injection  
HSDI high-speed direct-injection  
FIP fuel injection pressure  
FM particulate matter  
HHRR heat release rate  
BTE brake thermal efficiency  
BSFC brake-specific fuel consumption  
ASOI after start of injection  
CAD crank angle degree  
CI compression ignition  
LTR low-temperature reaction  
HTR high-temperature reaction  
L/HTC low-high-temperature combustion  
ATDC after top dead center  
HCHO formaldehyde
# Resource-Efficient Multicast URLLC Service in 5G Systems
## 4 Performance Evaluation
### Analysis of RB Allocation Algorithms  
Let us analyze the performance of FS and non-FS scheduling approaches. Similar to the previous section, we consider different numbers of antennas at the gNB: (i) 4 antennas, corresponding to 4G systems, and (ii) 64 antennas, corresponding to 5G M-MIMO systems. Figure 5a shows the following results. First, a higher number of antennas significantly increases SINR at UEs and reduces the DL resource consumption (from 20 to 40% depending on the number of UEs in the multicast group). Second, the usage of frequency selectivity (i.e., FS scheduling) provides lower resource consumption compared to non-FS scheduling. However, the gain of FS scheduling depends on the number of UEs and the number of antennas. Specifically, for a single UE, FS scheduling reduces resource consumption by 35% for 4 antennas and only by 15% for 64 antennas. The lower gain in the case of M-MIMO is explained by the channel hardening effect [40]: a higher number of antennas reduces the channel quality fluctuation both in time and frequency domains. When the number of UEs increases, the gain of FS scheduling significantly reduces. Specifically, when the multicast group includes more than ten UEs, the difference between FS and non-FS scheduling is less than 5% for both considered antenna configurations. The reason is that the channel quality in the RB \(j\) is determined by the UE with the lowest SINR: \(SINR_{j}\). For a higher number of UEs, the difference between \(SINR_{j}\) in different RBs reduces.  
Figure 4: Scenario with 3 kmph mobility, a single TX, the NACK-only feedback scheme, \(p_{1}=PLR^{QoS}\), and \(T_{SRS}=20\) ms.  
Figure 5b shows the average time needed to compute the schedule (including precoder construction) for a single slot. The results show that non-FS scheduling allows a significant reduction in the scheduler complexity--by 30% for 4 antennas and by 40% for 64 antennas. So, we can conclude that FS scheduling is fruitful only when the multicast group consists of a few UEs and the gNB has few antennas. For large multicast group size and M-MIMO systems, non-FS and FS scheduling approaches provide almost the same performance but the former has much lower computational complexity.