esa-sceva/satcom-chunk-collection huggingface dataset:
# NDVI or PPI: A (Quick) Comparison for Vegetation Dynamics Monitoring in Mountainous Area
## 4 Discussion
### Time-Series of the PPI and NDVI in Mountainous Areas for Different Vegetation Types  
Our results suggest that the PPI is a robust remotely sensed proxy for time-series retrieval and phenological monitoring, which could complement or substitute for NDVI in mountainous areas. Although NDVI is widely recognized for its ease of processing, it has notable limitations in snow-covered environments and dense vegetation canopies such as evergreen forests [36; 39; 40]. These limitations are evident in the pronounced noise during winter and at the beginning and end of the growing season (Figure 4). The length of the growing season is a critical determinant of vegetation productivity [24], making precise retrieval of the SOS and EOS crucial. NDVI's sensitivity to snow is also characterized by high variability at the start and end of the snow season [40]. Additionally, NDVI tends to saturate coniferous trees at levels similar to deciduous trees (approximately 0.8, Figures 4 and 6). [39] reported that NDVI struggles to accurately retrieve Gross Primary Production (GPP) for coniferous trees, resulting in a negative correlation for the sites studied.  
The PPI appears to mitigate these issues (Figure 5). However, consistent with previous studies [39; 40], the PPI tends to accentuate the signal during the peak growing season (Figures 5 and 6). This is due to its logarithmic formula, which increases sensitivity to variations in NIR and red reflectance [39].  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline
**LC Classes** & \multicolumn{6}{c}{**PPI**} & \multicolumn{6}{c}{**NDVI**} & \multicolumn{6}{c}{**Difference**} \\ \hline Deciduous trees & Year & SOS & EOS & Length & POS & SOS & EOS & Length & POS & SOS & EOS & Length & POS \\ \hline  & 2018 & 113 & 303 & 190 & 183 & 115 & 310 & 195 & 214 & –2 & –7 & –5 & –31 \\  & 2019 & 125 & 309 & 184 & 198 & 118 & 297 & 179 & 218 & 7 & 12 & 5 & –20 \\  & 2020 & 110 & 295 & 185 &
## 4 Seismic Response Spectra in the USA
### Site-Specific Spectrum According to ASCE/SEI 7-16
The accelerograms must be modified from a time function to a frequency function, \(A_{r}(\omega)\), by applying the Fourier transform technique, performing the mathematical convolution process between the functions \(A_{r}(\omega)\) and \(F(\omega)\), and then, applying an inverse Fourier transform to return the accelerations as a function of time. DeepSoil [7] and ProShake [8] can perform this mathematical process and obtain scaled accelerograms according to the soil dynamic properties related to the transfer function. Step 4: Obtain the mean response spectrum for all accelerograms and define the structural periods, \(T_{0}\) and \(T_{s}\). For each accelerogram previously modified with the transfer function, the response spectrum of each accelerogram and the geometric mean can be obtained. The process is similar to step 4 previously presented in Section 3.4. Using DeepSoil [7] or ProShake [8] programs, the geometric mean response spectrum can be obtained. With the spectral graph available, it is possible to visually determine the periods and maximum spectral acceleration values, where the parameter \(S_{DS}\) for short periods is located between the periods \(T_{0}\) and \(T_{s}\) and the parameter \(S_{D1}\) is located at a period of 1.0 s. The period \(T_{L}\) can be obtained directly from ASCE/SEI 7-16 maps [2] or USGS webpage [18]. Finally, an increase of at least 15% in \(S_{DS}\) and \(S_{D1}\) values must be created, including the distance between the periods \(T_{0}\) and \(T_{S}\), due to the uncertainties in the soil layer inputs related to the field. As an alternative procedure, a Monte Carlo simulation can be performed to obtain an adjusted amplification percentage to be applied on the previous parameters. Step 5: Obtain the elastic design spectrum for the study site. Figure 17: Example of the target spectrum for El Centro, CA, and scaled real earthquakes. With the acceleration values, \(S_{DS}\) and \(S_{D1}\), the periods \(T_{0}\) and \(T_{S}\) previously obtained in step 4, and period \(T_{L}\) from the maps provided by ASCE/SEI 7-16, the elastic design spectrum can be developed by applying Equation (32).
## 4 Metasurfaces for OAM Beam Generation  
The conventional methods to generate vortex beams in microwave region have been discussed in the previous section. In the case of the circular phased array antennas, a complex feeding system should be implemented to accomplish spiral phase distribution with consistent power delivery. Besides, it needs more antenna elements when the number of OAM modes increases which will lead to a feed network more complex in the design process. Phase plates and reflectors are bulky structures that are usually not suitable for implementation in modern communications systems. Recently, metasurfaces (MS) have drawn much attention due to the unique ability of arbitrary wavefront control, such as amplitude, phase and polarization state of EM waves. Compared to metamaterials, metasurfaces are two-dimensional surface arrays with the advantages of low profile, light weight and ease of fabrication. For OAM generation, we classify metasurfaces into two main categories: reflective and transmissive. For reflective MS, amplitude attenuation is generally negligible and only a single layer of structure is generally required to achieve the coverage of the spiral phase. In contrast, transmissive MS for OAM generation are in most cases composed of several layers to achieve the required \(2\pi\) phase shift needed for plane wave to vortex wave conversion and attention has to be paid to losses in the multi-layer structure.  
Figure 7: Photography of the first experimental prototype of a phased antenna array for OAM vortex wave generation and its measured phase pattern [36].
# Improved Control of Forest Microgrids with Hybrid Complementary Energy Storage
## 3 Hybrid Complementary Energy Storage System
### Predictive Converter Control Method
#### 3.3.2. Objective Function of the Converter Predictive Control  
In order to realize fast regulation of the inner loop current of the converter, predictive control should aim for fast tracking of the reference current generated from the outer loop, as shown in Equation (9).  
\[J=\bigr{|}i_{\mathrm{sto}}(k+1)-I_{\mathrm{sto}}^{*}\bigr{|}. \tag{9}\]  
On the basis of collecting the state information of the system at the current moment, the predicted values of the converter inductor current under different switching states can be calculated though the prediction model. The switch state with the smallest deviation between the predicted current and corresponding reference value is then selected as the system output to control the converter. As a result, fast current tracking can be achieved through active predictive control.  
By combining the model predictive method of current inner loop with the adaptive droop control in the outer loop of the energy storage control system, fast power regulation of energy storage units under various working modes can be achieved, which stabilizes the DC voltage. The general control chart of the predictive method with adaptive droop control in the outer loop for different energy storage units is presented in Figure 6.  
As mentioned before, the supercapacitor is appropriate for suppressing high frequency power fluctuations with small amplitude, which are hard for the biomass thermal unit or the battery to stabilize. On the contrary, the battery, which has large amount of stored energy and high energy density, is always utilized as a long-term power balance device to absorb or release power with low frequency. The reference current absorbed or released by the energy storage system is divided into two parts, namely, the low-frequency part and the high-frequency one, through the low pass filter LPE. The corresponding control block diagram of the hybrid energy storage system is shown in Figure 7.
# Enhanced LDM for Next-Generation Digital Broadcasting Transmission
## 5 Conclusions  
This paper proposed a multi-service transmission scheme called En-LDM, which can support the simultaneous transmission of robust HDTV mobile services and high-data-rate UHDTV fixed services. Comparison with the performance of the traditional LDM system demonstrated the significant performance advantage of the En-LDM, especially in the more practical multipath channel environment. Theoretical analysis and computer simulations showed that the receiving SNR threshold of the fixed services in the En-LDM system was lower than that of the traditional LDM system while maintaining the receiving SNR threshold of mobile services. Eventually, the overall channel capacity of the En-LDM  
Figure 11: BER performance of fixed service with En-LDM and traditional LDM systems in the multipath channel under different code rates, where the injection level was set to \(\Delta=12\) dB, the CL constellation was set to QPSK, the EL constellation was set to \(\mathrm{NU}-64\mathrm{QAM}\), the puncturing rate of En-LDM scheme was set to 1/13, and the LDPC code rates of EL were set to CR = 9/15 and 11/15.  
system was 0.97 Mbit/s higher than that of the traditional LDM system with a slightly channel capacity loss of mobile service transmission.  
To some extent, it is inferred that the proposed En-LDM system can effectively narrow the coverage gap between mobile services and fixed services at the same RF side without sacrificing the coverage performance of mobile services.  
Conceptualization, X.D.; methodology, X.D. and M.L.; software, X.D.; formal analysis, X.D.; investigation, X.D. and X.B.; resources, X.D.; data curation, X.D.; project administration, X.D.; writing--original draft preparation, X.D., X.B., M.L.; writing--review and editing, X.D.; supervision, M.L. All authors have read and agreed to the published version of the manuscript.  
This work was supported in part by the National Key R&D Program of China under Grant 2019 YFB1802703, in part by the Shanghai Technical Standard Project of China under Grant 18 DZ2203900, and in part by the Shanghai Excellent Academic Leader Program of China under Grant 18 XD1404100.  
Not applicable.  
The authors declare no conflict of interest.
## 3 Results and Analysis
### Quantitative Impact of Climate Change on Compound Flood Drivers
#### 3.1.2 Storm Surges  
Climate change leads to an increase in sea surface temperature, resulting in a significant rise in the frequency and intensity of tropical cyclones globally, thereby increasing the risk of storm surges [51; 52]. In the context of sustained SLR, strong typhoons and storm surges can easily produce catastrophic water levels, especially when combined with high sea levels and astronomical tides, which can lead to extreme high tide levels. Numerical simulation methods are commonly used to model the complex physical processes of storm surges under climate change [53]. Table 2 presents the literature and numerical models used to calculate the impact of climate change on storm surges. The two-dimensional Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model, based on depth-integrated shallow water equations, is widely used for storm surge prediction in most countries due to its simplicity, speed, and minimal computational requirements [54]. However, its limitations include low resolution and an inability to account for wave run-up caused by astronomical tides and nearshore processes.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Reference** & **Study Area** & **SLR** & **Numerical Model** \\ \hline [PERSON] et al. [44] & The coastal region of Bangladesh & 0.26 m (2050) and 0.54 m (2100) & Delft3D \\ [PERSON] et al. [38] & Shanghai, China & 0.13 m (2030) and 0.25 (2050) & MIKE 21 \\ [PERSON] et al. [45] & Kuwait & 0.5 m, 1 m, 1.5 and 2 m & ArcGIS \\ [PERSON] et al. [46] & China’s Pearl River Delta & 0.3 m, 0.5 m, 0.9 m and 2.1 m & FVCOM \\ [PERSON] et al. [47] & Baltic Coast, Lithuania & 1 m & HEC-RAS \\ \hline \end{tabular}
\end{table}
Table 1: Numerical model of sea level rise impact on compound floods.  
With advancements in computer technology and algorithms, three-dimensional (3D) ocean circulation numerical models are increasingly being applied to storm surge simulation and operational forecasting, such as ADCIRC, Delft3D, and FVCOM models. For example, the 3D finite element ADCIRC (Advanced Circulation) model has been used to evaluate the impact of climate change on storm surge inundation along the U.S. coast. Research findings indicate that both the extent and frequency of storm surge inundation in regions like the Gulf of Mexico have increased in recent years, and the future impact of climate change on storm surges may become even more challenging to predict [58]. The three-dimensional storm surge model better simulates the physical evolution process of ocean circulation and storm surges and can provide more precise forecasts than the two-dimensional models. However, the three-dimensional storm surge models require significant computational resources and entail a much larger computational workload [60].
# Performance of Strengthened Accelerated Oscillator Damper for Vibration Control of Bridges
## 3 Composition and Working Principle of the NSD
### Verification of the Functional Relationship between \(F\) and \(z\)  
To validate the accuracy of Equation (20), the NSD is evaluated using FE analysis. The parameters chosen for this simulation, specifically for Example 2, are as follows: The spring constant \(k_{A}\) is set to 97 kN/m and \(k_{B}\) to 221.8 kN/m, with lengths \(l_{1}\), \(l_{2}\), and \(l_{3}\) being 0.3 m, 0.1 m, and 0.2 m, respectively.  
In the FE modeling process, initially, we make the assumption that the model is a two-dimensional planar model. The connecting rod is represented using a truss element, Spring A is modeled as a standard spring element, and Spring B is simulated as a nonlinear spring element. Given the NSD's symmetry, it is advisable to consider Terminal A as the stationary terminal and Terminal B as the mobile one. So, assuming that all degrees of freedom of Terminal A are completely restricted. Terminal B undergoes forced displacement in the \(z\)-axis as illustrated in Figure 3b, and multi-step loading is facilitated by setting the number of displacement increments. By calculating the reactive force at Terminal B, we obtain the FE numerical solution for \(F\). A comparison between the FE solution and the analytical data derived from Equation (20) is presented in Figure 4.  
Figure 4 demonstrates the validity of Equation (20). Consistent with the analysis conducted using Equation (20), during compression of the device, \(F\) can be decomposed into two components: the component force from Spring A and the potential force from the highly stiff Spring B. During tension, while Spring B remains inactive, it becomes apparent that the change in angle of the connecting rods within the NSD leads to a notable increase in \(F\).  
In practical applications, the force and displacement of the required NSD should be calculated. Then, using Equation (20), the appropriate stiffness coefficient and stroke of Spring A and Spring B, as well as the connecting rod length, should be determined. Finally, the structure of the NSD will be ascertained. Materials have become more and more important in terms of high-strength spring steel [43], and a wide variety of high-strength spring steels are available to satisfy demand. For example, [PERSON] et al. discovered that 55 SiCrVNb had good yield strength and tensile strength after treatment [44].
# Experimental Evaluation of Unicast and Multicast CoAP Group Communication
## 5 Evaluation
### Performance Evaluation on a Wireless Sensor Testbed
#### 5.2.2 Reliability
In contrast, our unicast-based group communication maintains 100% reliability for the 10- and 20-member groups, even with the maximum transmission speed of the Wi-Fi nodes, and only drops to 98% in the case of the 30-member group. These results are generally in line with the simulations that we performed previously in [9]. However, a direct comparison is not possible, since the simulations used a more controlled topology, in which five nodes were one-hop away, another five nodes were two hops away, and so on. On the testbed, the location of the nodes is fixed, and it was up to RPL to construct the topology for the routing. Furthermore, the simulations randomly dropped packets at a configurable percentage to simulate external interference, while on the testbed, real Wi-Fi traffic at one point of the network was used. The drawbacks of the improved reliability of our unicast-based approach are the increased network overhead and response time. These are expected results, since the reliability is achieved by transmitting acknowledged messages, which results in more messages and longer delays in the case of errors. We have discussed these issues in detail in our previous work [9]. Figure 10: Member reliability for both unicast and multicast group communication and varying group sizes in the presence of Wi-Fi interference. The member reliability is much better when using unicast-based group communication.
# Advances in Organic and Organic-Inorganic Hybrid Polymeric Supports for Catalytic Applications
## 4 Metal-Catalysed Non-Asymmetric Reactions
### C-C Coupling Reactions
Heteroatom-functionalized biparls were obtained in excellent yields at mild temperatures (20 or 50 \({}^{\circ}\)C) and in very short reaction times (10 min-4 h) (Scheme 58a). Influence of steric effect given by substitution in phenylboronic acids or aryl halides was also evaluated. For this reason, a series of reactions was carried (Scheme 58b). High yields were obtained with all substituted boronic acids, except that with boronic acids containing electron-withdrawing and bulky _ortho_ substituents with which the desired products were not obtained. The presence of bulky and electro-withdrawing _ortho_ functionality in aryl halide determined only a slight decrease of yield. Superior results were obtained when the heterocyclic moiety belonged to the boron transmetallation partners (Scheme 58c); a better tolerance towards multiple coordinating heteroatoms was noticed. The Pd leaching was investigated observing its dependence on the nature of the substrates and the reaction condition. In absence of heteroatoms in substrates, the Pd content in solution after filtration of the catalyst was in most cases <0.1 ppm. However, when one N atom was present in the aryl halides, leached Pd amount was very small (2.8-5.0 ppm) and proved to be dependent on the reaction time and temperature. At elevated temperatures and under MW irradiation, even higher levels of Pd could be detected (12-14 ppm). After having studied **Pd-MIL-101-NH\({}_{2}\)** under batch conditions, its behavior in continuous-flow conditions was investigated. For the first time, metallic nanoparticles supported on metal-organic framework were employed in a packed-bed micro-flow reactor for catalytic applications. Twelve bairols were synthesized without replacing the catalyst, demonstrating the potential of the catalyst for large-scale applications (Scheme 58d). The catalyst showed a good stability under a continuous flow regime with very slight leaching of metallic species.
## 2 Problem Definition and Scenario of Application
### Mathematical Characterisation  
The TLP aims to find the optimal combination of tables in space maintaining the social distancing. This combinatorial problem must be discretized in order to explore a contained number of possible solutions configuring an exploratory attainable problem [43]. The number of possible combinations can be calculated as follows:  
\[P=\prod_{i=0}^{n_{t}-1}\left(n_{ptl}-i\right), \tag{1}\]  
where \(P\) is the number of possible combinations of tables in the defined scenario, \(n_{t}\) the number of tables to be located in the scenario and \(n_{ptl}\) the number of the possible locations for the tables defined through the discretization of the scenario. This discretization has been done based on slightly changes in the attainment of the optimal fitness values of the TLP [37].  
Therefore, a set \((T)\) can be defined containing all the possible solutions of the TLP. The aim is to find the subset \((\langle T_{i}\rangle=\langle t_{1},\ldots,t_{mt}\rangle)\) which is formed by the coordinates of each of the \(n_{t}\) tables in space which maximises the fitness function.  
Therefore, the mathematical model for the optimisation of the TLP is detailed hereafter:  
\[\begin{split}\text{Maximise}\ Z=ff(T_{i})\\ \text{Subject to:}\\ x_{lim_{1}}\leq x_{i}\leq x_{lim_{2}};\quad\forall\ x_{i}\in t_{i}; \quad t_{i}\in T_{i};\quad t_{i}\
ot\in U\\ y_{lim_{1}}\leq y_{i}\leq y_{lim_{2}};\quad\forall\ y_{i}\in t_{i}; \quad t_{i}\in T_{i};\quad t_{i}\
ot\in U\\ d_{ij}\geq d_{sd}\ \forall i,j\in[1,n_{t}];\quad i\
eq j\\ d_{io}\geq d_{w},\end{split} \tag{2}\]  
where \(x_{lim_{1}},x_{lim_{2}},y_{lim_{1}},y_{lim_{2}}\) are the lower and upper bound for the Cartesian coordinates of the tables in the defined environment; \(U\) is the subset of \(T\) containing the forbidden regions of the simulations environment for locating any table (e.g., the bar counter or regions for the movement of the waiters or clients) and \(d_{ij}\) the Euclidean distance among two different tables \(i\) and \(j\) of the subset \(T_{i}\), being \(d_{ij}\) greater than the minimum interpersonal distance \(d_{sd}\), in this paper, 1.5 m as established by the Spanish legislation. The distance from table \(i\) to the closest obstacle is defined as \(d_{io}\), which must be greater than the serving distance \(d_{w}\), for the waiter to attend all tables.  
The introduction of the Euclidean distance as a way to measure the quality of a table disposition and as a restriction in the TLP makes it to be a non-linear optimisation. This definition, together with the discontinuity of the fitness function, favour the introduction of metaheuristics for addressing this research problem.
# Oceania's 5G Multi-Tier Fixed Wireless Access Link's Long-Term Resilience and Feasibility Analysis
## 3 5G Base Coverage Network Layout
### Resilient Communication Is Made Possible for the Linked Intelligent Edge by 5G
A resilient 5G system's technical capabilities combine security, privacy protection, robustness, availability, and reliability. These key characteristics are already present in today's telecom networks and are expanded even more by new tools and skills. Existing crucial societal functions are being increasingly shifted online and are starting to rely on telecom networks. New use cases are being realized at the same time as new capabilities are emerging. Due to this, traditional telecom networks are becoming the main innovation platform for business and society. Mission- and business-critical use cases have increased the demand on the 5G system. To protect against the constantly changing risk and threat landscape in the various stages of the supply chain and operations, networks must be used to realize the Internet of Senses, connected intelligent machines, digitalized and programmable physical world, and connected sustainable world. It is even more important that security controls and assurance procedures are seamlessly integrated for AI-based security and trust management on the operations side. The foundation for supporting the most demanding societal, mission, and business-critical use cases is a secure, resilient, and privacy-preserving network platform with demonstrated performance in challenging environments in a verifiable manner. All product lifecycle phases, including network development, deployment, and operation, must have built-in security automation and assurance capabilities. It is feasible to react in real time to known and undiscovered threats thanks to improved security and critical service assurance procedures, AI-based security, and trust management. The intelligent network platform offers varying degrees of security, privacy, dependability, availability, and resilience depending on the use cases. On the path from 5G to 6G, various building components have been found to realize these properties.