esa-sceva/satcom-chunk-collection huggingface dataset:
## 4 Conclusions  
We analyzed LEO satellite downlinks under interference situations when airborne interference sources move parallel to the LEO satellite trajectory by considering relative angle differences between satellites and interference sources. To make interference situations more like actual environments, the LEO trajectories were obtained from TLE data. Airborne interference sources with various altitudes moved parallel to the satellite trajectories, and the \(J/S\) ratio was calculated according to the relative angle differences between the ground station, satellite, and interference source. In order to calculate the relative angle difference \(\psi\), the satellite and interference source coordinates were converted from the WGS84 to the ENU coordinate system. By applying the relative angle difference \(\psi\), we obtained the sidelobe gain of the ground station antenna in the direction of the interference from the ground station antenna. Through a comprehensive link budget analysis, the \(J/S\) ratio was found to be 22.5 dB higher in Trajectory 3, where the relative angle difference \(\psi\) was small compared to the other trajectories. These results showed that the relative angle difference \(\psi\) is more important in the \(J/S\) ratio than the distance between the ground station and the interference source or satellite.  
Conceptualization, H.C. and E.K.; methodology, E.K., J.K. and H.C.; software, E.K.; validation, E.K., J.K. and H.C.; formal analysis, E.K. and H.C.; investigation, E.K.; resources, E.K. and H.C.; data curation, E.K. and H.C.; writing--original draft preparation, E.K.; writing--review and editing, E.K., J.K., Y.P. and H.C.; visualization, E.K. and H.C.; supervision, H.C.; project administration, Y.P.; funding acquisition, H.C. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the Agency for Defense Development (UI210013 YD).  
Data are contained within the article.  
The authors declare no conflicts of interest.
## 1 Introduction
### Superconductor Applications for Vehicles
#### 1.1.2 The Hyperloop Concept  
The Hyperloop concept is an electric vehicle that uses magnetic attraction or repulsion to achieve levitation over the designed track. The vehicle is often operational in a vacuum tube, which leads to increased efficiency while driving by lowering the drag resistance. Compared to the vehicles found in the aviation industry, the energy used by Hyperloop represents only a fraction.  
The Maglev system was developed to replace conventional means of transport, which uses the properties of magnetic attraction or repulsion to propel a vehicle at high speed. In contrast with the Hyperloop concept, Maglev does not use a vacuum tube. This vehicle levitates above the track by using magnetic forces, as shown in Figure 4, thus eliminating the frictional forces on the rail.  
There are several different means of levitation and propulsion based on the principles of magnetism. The first option is using a magnetic attraction topology, also known as electromagnetic suspension (EMS), which provides a higher attraction force from the rail to the vehicle to compensate for the gravitational force. The second option represents an electrodynamic suspension (EDS) that uses magnetic repulsion to achieve levitation above the rail; it is also used by the Maglev vehicle and certain currently implemented Hyperloop topologies [13].  
Several possible applications of cryogenic cooling and black-box modeling have been put forward, including transport industries, medical applications, and other scientific research topics. Over the next sections, theoretical principles, experimental results, and further limitations are covered.
## 2 An Efficient Algorithm for Moment-Independent Importance Analysis
### The Procedures of the Proposed Method  
The moment-independent sensitivity analysis procedure involved in the modified 4 PEM and SGLD is summarized as follows.  
1. Set the input vector \(\mathbf{X}\) composed of the uncertain parameters from structural and material properties.
2. Implement 4 PEM to the structural uncertain parameter vector \(\mathbf{X}\) to obtain the locations \(\chi_{i,j}\) and weights \(w_{i,j}\).
3. Change the uncertain parameters in the structural model according to \(\left(\mu_{1,}\mu_{2},\cdots\chi_{i,j}\cdots\mu_{n}\right)\) and obtain the samples of seismic demand \(Y_{i,j}\) through NTHA.
4. Calculate the first four moments of \(Y\) by Equation (6).
5. Evaluate \(f_{Y}(y)\) through SGLD.
6. Fix \(X_{i}\) at \(\chi_{i,j}\) and implement 4 PEM to \(\mathbf{X}_{-i}\) to obtain the new locations \(\chi_{k,p}^{(-i)}\) and weights \(w_{k,p}^{(-i)}\). Repeat step (2)-(4) to obtain \(f_{Y|X_{ij}}(y)\).
7. Calculate the expectation \(E_{X_{i}}[s(X_{i})]\) by Equations (12) and (11) and obtain the MII index by Equation (4).
8. Repeat step (5) and (6) until the MII index calculation of all the variables of \(\mathbf{X}\) is finished.  
The procedures of this section are summarized in Figure 1.  
It is worth noting that the samples for NTHAs with this new integrated algorithm are only \(n\times n\times 4\), while the MC simulation [24] requires a large number of NTHAs. In MC procedure, the \(Nx\) realizations of \(Y\) can be obtained from \(Nx\) NTHA by inputting \(Nx\) samples of \(\mathbf{X}\). \(f_{Y}(y)\) can be evaluated from the realizations of \(Y\) by kernel density estimation. By the same procedure, \(f_{Y|X_{i}=x_{i,1}}(y)\) can be evaluated by fixing \(X_{i}=x_{i,1}\) in which \(x_{i,1}\) is one of the \(N\)s samples of \(\mathbf{X}_{-i}\). The evaluation of the conditional PDF is then repeated with all \(N\)s samples. Then, the expectation \(E_{X_{i}}[s(X_{i})]\) can be obtained by averaging the estimates \(s(x_{i,1\sim N\text{s}})\). Using MC simulation to derive NII indexes clearly involves a large number of samples, including \(Nx\) samples for unconditional PDF calculation and \(N\text{s}\times Nx\) for every variable of \(\mathbf{X}\), so \(N\text{s}\times Nx\times n+Nx\) in total. The smallest useful number of samples for MC simulation is about 100, so if \(N\text{s}=Nx=100\), that results in requiring more than \(10^{4}\) samples for each variable. For civil structures, one sample means one propagation through an NTHA for a large engineering finite element model. Clearly, MC simulation may entail a huge computation burden, to the point that it might even be difficult to calculate the MII index for structural seismic demand. Evidently, this new integrated algorithm dramatically improves the computational efficiency compared to MC simulation.
# Functionality of the Search and Rescue Transponder (SART) in Maritime Search and Rescue Actions
###### Abstract  
In this article, the authors present contemporary problems in search and rescue operations at sea. The research focuses on the detection of the SART (Search and Rescue Transponder) device. This device is used to call for help and assist the rescuing vessel in tracking. Issues with their functionality may reduce the likelihood of finding a survivor. The authors designed an experiment to assess the effectiveness of using the device. The research conducted is a real-world experiment that involved a ship radar, a liferaft, a SART device, and a radar reflector. The experiment consisted of multiple trials to detect, locate, and track the device, as well as to assess the radar image features. Four scenarios were developed, considering different distances and radar settings. Performance evaluation indicators were also developed. The results are presented both graphically and numerically. A brief discussion of the obtained results and concise conclusions are provided. Along with the research findings, recommendations for the use of SART and radar on ships are also presented, as well as recommendations for improving training. The results are applicable to improving the effectiveness of SAR operations.  
search and rescue; radar transponder; detection; SART; survivor Article
###### Abstract  
In this paper, the relationship between the terahertz radiation and the spatial distribution of photogenerated carriers under different bias electric field is studied. Terahertz pulses and the photocurrent of SI-GaAs photoconductive antenna are measured by the terahertz time-domain spectroscopy system. The occupancy rate for photogenerated carriers for different energy valleys is obtained by comparing the photocurrent of terahertz field integrating with respect to time with the photocurrent measured by oscilloscope. Results indicate that 93.04% of all photogenerated carriers are located in the \(\Gamma\) valley when the bias electric field is 3.33 kV/cm, and 68.6% of all photogenerated carriers are transferred to the satellite valley when the bias electric field is 20.00 kV/cm. With the bias electric field increasing, the carrier occupancy rate for the satellite valley tends to saturate at 72.16%. In order to obtain the carrier occupancy rate for the satellite valley and saturate value at the high bias electric field, an ensemble Monte Carlo simulation based on the theory of photo-activated charge domain is developed.  
Keywords:semi-insulating Gallium arsenide (SI-GaAs); photoconductive antenna; multi-energy valley scattering; terahertz time-domain spectroscopy +
Footnote †: journal: Applied Physics Letters B
## Determination of Sesquiterpenes in Wines by HS-SPME Coupled with GC-MS  
**[PERSON], [PERSON] *, [PERSON] and [PERSON]**  
Department of Chemical Science, University of Messina, Viale F. Stagno d'Alcontres, 31 98168 Messina, Italy  
* Author to whom correspondence should be addressed; E-Mail: [EMAIL_ADDRESS]; Tel.: +39-090-6765167.  
Academic Editor: [PERSON]  
_Received: 26 March 2015 / Accepted: 3 July 2015 / Published: 9 July 2015_  
**Abstract:** The sesquiterpene compounds present in red wines were characterized and quantified by Headspace Solid-Phase Microextraction in combination with Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS). Sixteen sesquiterpenes were identified, mainly hydrocarbons but also derived oxygenated compounds. Sesquiterpenes were acyclic, monocyclic, byciclic and tryciclic. Sesquiterpenes were detected in SIM (selected ion monitoring) mode using their characteristics ions. All the sesquiterpenes were identified by mass spectral data, linear retention indices (LRI), literature data and injection of standards where available. Quantitative results were obtained using the method of standard additions. The method showed an average LOD = 0.05 \(\upmu\)g L\({}^{-1}\) and LOQ = 0.15 \(\upmu\)g L\({}^{-1}\). The monocyclic sesquiterpene with the germacrene skeleton, Germacrene D and the bicyclic sesquiterpene with the murolane skeleton, \(\alpha\)-muroclene were present in all the wine samples analysed. Syrah wines were the samples richest in sesquiterpenes in agreement with their typical spicy and woody notes. The results evidenced the possibility to use sesquiterpenes for wine authenticity and traceability.  
**Keywords:** sesquiterpenes; red wines; HS-SPME-GC-MS
# Random Access Using Deep Reinforcement Learning in Dense Mobile Networks
## 3 Problem Formulation and System Model
### Traffic Model  
To evaluate the effectiveness of the proposed approach, we include a more congested scenario in the experiment using 3 GPP's synchronized traffic model 2 [37]. This refers to many machine-type devices accessing the network almost simultaneously. The traffic model from 3 GPP allows us to experimentally model a congested network. The probability density function of the beta distribution is given as follows.  
\[g(t)=\frac{t^{\alpha-1}(T-t)^{\beta-1}}{T^{(\alpha+\beta-1)}B(\alpha,\beta)}, \tag{1}\]  
\[B(\alpha,\beta)=\int_{0}^{1}\!\!t^{\alpha-1}(1-t)^{\beta-1}dt, \tag{2}\]  
where \(t\) is the time of access opportunity at a given time, \(T\) is the duration of the activation of the devices, \(\alpha\) and \(\beta\) are shape parameters of the beta distribution.
###### Abstract
Although adaptive modulation has been widely investigated in the literature (e.g., [26; 27; 28; 29]), no work has been dedicated to performing modulation awareness for these systems over wireless selective channels. This confirms the novelty of this work. It is important to highlight the fact that AF cooperative systems are superior to DF cooperative systems in terms of capacity and processing. * This study makes use of the temporal redundancy present in the structure of received signals to create correlation functions that include spikes for one set of modulations but not for others. * With the assistance of this attribute, a multiple-layer AMA technique is constructed on the notion of false-alarms. The proposed algorithm has the following advantages. * The suggested method does not require any information about the channel coefficients or the strength of the noise. * The suggested method runs over any kind of wireless channels including frequency-flat and frequency-selective channels. * The suggested method provides a simplified processing requirement. * The suggested method does not required any pilot symbols to start the awareness process. This makes it appropriate for use in both military and civilian contexts. The rest of this work is as follows. Section 2 describes the system model. Sections 3 and 4 cover the cross-correlation functions for different modulation types as well as the method under consideration. Section 5 presents the results of the simulations. Section 6 contains the final conclusions.
## 5 Discussion
### Limitations and Future Research  
Despite the promising results and contributions of this study in predicting the ultimate bearing capacity (UBC) of shallow foundations on cohesionless soils using advanced soft computing techniques, there are certain limitations that should be acknowledged. One limitation is the reliance on historical data for model development and validation. The accuracy and performance of the AI models heavily depend on the quality and representativeness of the available data. Therefore, future research should focus on expanding the dataset and including data from a broader range of soil conditions and foundation geometries to enhance the models' generalization and applicability to diverse engineering scenarios.  
Another limitation lies in the assumption of certain soil behaviors and conditions. The AI models developed in this study may not capture certain complex geotechnical phenomena, such as soil liquefaction or soil-structure interaction effects, which can significantly influence the bearing capacity of shallow foundations. Incorporating additional factors and advanced modeling techniques to address these complexities can further improve the accuracy and reliability of UBC predictions in more challenging geotechnical conditions.  
Furthermore, the present study only considers cohesionless soils, while, in practice, engineers encounter various types of soils with different characteristics. Extending the AI models to account for cohesive soils and investigating their performance in mixed soil conditions can enrich the predictive capabilities of the models and enable a more comprehensive assessment of foundation bearing capacity.  
Additionally, it is essential to recognize that the predictive accuracy of the AI models is subject to the quality and availability of input parameters. In practice, obtaining precise measurements of certain parameters, such as internal friction angle, might be challenging due to site-specific constraints. Integrating advanced geophysical and non-destructive testing techniques to estimate soil properties can contribute to more accurate and reliable data inputs for the AI models.  
Moreover, while the sensitivity analysis conducted in this study provides valuable insights into the influence of individual input parameters, exploring the effects of other potential factors, such as groundwater table variations, temperature, and time-dependent soil behavior, can further enhance the models' predictive capabilities and broaden their applications.
# Alternative Pedicle Screw Design via Biomechanical Evaluation
## 2 Alternative Pedicle Screw Design
The product 'Dual lead OSTEOGRIP(r)', which is produced by Medtronic, was similar to the alternative pedicle screw studied in this work. The alternative was longer and thinner than the commercialized product. The product does not have a marked length difference between the two threads, whereas the alternative had a long main thread compared to its sub-thread. These can show different structural behaviors, such as stress concentration, tensile strength, and fatigue compared to the commercialized product. In fact, the shape and dimensions of the alternative were modified to relax the stress concentration. The screw had a shank, sub-thread, and main thread from the head to the tail. The contour from the head to the shank was a smooth curve, because stress concentration can occur if this is inappropriate. The shank was designed to be shorter than current pedicle screws to make it stronger, because the shorter length gives higher stiffness against loading due to torque, bending, and tension. In addition, the sub-thread had a finer pitch, which results in a larger cross-section of the screw, which makes the tensile stress area wider so that the screw can support higher loads. The finer pitch prevents loosening. Furthermore, the sub-thread had a quadruple thread and the main thread was a double thread, which both helped to reduce the surgery time. Thus, the alternative screw design with quadruple and double threads was robust against fracturing of the shank and minimized surgical inconvenience. Despite the previous study's improvement, the stress concentration should be relaxed more in the transition section between the main thread and the sub-thread. The connection between the double and quadruple screws was designed to be smooth with no discontinuity. The cross-sectional changes between them were smoothly tapered. In this hybrid design, the stress concentration due to loading was investigated both experimentally and via FEA. The overall structural robustness of the design was also analyzed by considering the attachment of the screw to the vertebrae.
# Data Exchange in Cluster Structure for Longevity of IoT
## 3 Proposed Property-Based Data Transfer  
### Motivation and Strategies  
In the WSNs, since routing algorithms are employed to transfer the data from the sensor nodes to the central server, each sensor node has to sustain only the routing path to the server. However, in the IoT environment, various things can directly interconnect with other things without a server. They can request data exchanges with other things. Hence, in addition to the central server, routing paths connected to various things are created and maintained in the working space of each thing. These working conditions require significant energy and storage resources. These requirements cause a heavy burden on things with limited resources. Therefore, we require a new strategy to solve these problems.  
In the IoT environment, the data measured and produced by the things are classified according to the type of use. For example, if the distance between things is measured, the data measured by the ultrasonic sensor, infrared sensor, received signal strength indicator (RSSI) in Bluetooth, and other sources can be utilized. However, these data can be used to infer a specific property, i.e., \"distance\".  
To share information, when data exchange between things is necessary, the properties of the things can be utilized. If only the things related to the specific property participate in the data exchange process, instead of involving all the things, the network traffic can be reduced significantly. Hence, energy consumption in the IoT network also decreases significantly. Therefore, if a group is formed with the things located close together and a leader node, and if the leader of each group sustains the property information of the other groups, a thing can exploit the property information of all the groups with a small amount of resources. The group is called a property-based cluster (PC), which is composed of a header node and several member nodes.
## 3 Results and Discussion
### Effect of Environmental Matrix  
The effluent water from Nanjing Jiangxinzhou sewage treatment plants, surface water from the river of Nanjing University Xianlin Campus, deionized water, and a tap water were used to study the effect of sample matrix on BPA adsorption. The main properties of these water samples were shown in Table 2. The adsorption of BPA in tap water and surface water was higher than that obtained in deionized water (Figure 9). The adsorbed amount of BPA in sewage treatment plant water decreased by 4% compared with that in deionized water. All results showed that the effect of environmental matrices on BPA adsorption was not evident. Mag-PVP was an excellent adsorbent to remove BPA from environment water samples.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Water Samples** & **Deionized Water (D)** & **Tap Water (T)** & **Surface Water (S)** & **Effluent Water (E)** \\ \hline Temperature (\({}^{\circ}\)C) & 19.8 & 19.8 & 19.9 & 19.9 \\ pH & 7.1 & 8.3 & 8.4 & 8.6 \\ Conductivity (\(\mu\)S/cm) & 1.2 & 241.4 & 348.3 & 1120.3 \\ Total organic carbon (mg/L) & 0 & 0.2 & 2.6 & 10.1 \\ \hline \hline \end{tabular}
\end{table}
Table 2: The main properties of the water samples.  
Figure 8: Possible mechanism for BPA adsorption on Mag-PVP.  
Figure 7: **(a)** Zeta-potential of Mag-PVP as a function of pH values; **(b)** Effect of pH on BPA adsorption by Mag-PVP and XAD-4 (BPA concentration = 20 mg/L; adsorbent dosage = 0.2 g/L; shaking time = 4 h). Error bars represent standard deviation values from three replicates.
# Wavelet-Based Estimation of Damping from Multi-Sensor, Multi-Impact Data
## 5 Results and Discussion
### Experimental Analysis
The Yoshida and pLSCF methods have different damping values compared to the CTWT, LSRF, and PP methods and may exhibit higher errors. Based on simulation results, the CTWT-2 method is likely closer to the true value. Despite its \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Method**} & \multicolumn{2}{c}{**4.71 Hz**} & \multicolumn{2}{c}{**17.81 Hz**} & \multicolumn{2}{c}{**27.68 Hz**} \\ \cline{2-7}  & \begin{tabular}{c} **Damping** \\ **Ratio** \\ \end{tabular} & **Variance** & \
\begin{tabular}{c} **Damping** \\ **Ratio** \\ \end{tabular} & **Variance** &
\begin{tabular}{c} **Damping** \\ **Ratio** \\ \end{tabular} & **Variance** \\ \hline CTWT-1 & 0.0308 & \(2.72\times 10^{-4}\) & 0.0086 & \(1.52\times 10^{-6}\) & 0.0093 & \(2.14\times 10^{-6}\) \\ CTWT-2 & 0.0482 & \(1.58\times 10^{-6}\) & 0.0084 & \(2.11\times 10^{-9}\) & 0.0092 & \(1.20\times 10^{-9}\) \\ LSRF & 0.0411 & \(2.09\times 10^{-4}\) & 0.0090 & \(2.32\times 10^{-5}\) & 0.0088 & \(7.85\times 10^{-7}\) \\ pLSCF & 0.0210 & \(1.17\times 10^{-4}\) & 0.0034 & \(1.02\times 10^{-7}\) & 0.0032 & \(5.48\times 10^{-6}\) \\ PP & 0.0521 & \(1.09\times 10^{-3}\) & 0.0074 & \(4.98\times 10^{-6}\) & 0.0094 & \(4.13\times 10^{-6}\) \\ Yoshida & 0.0150 & \(2.03\times 10^{-4}\) & 0.0058 & \(7.03\times 10^{-6}\) & 0.0040 & \(2.17\times 10^{-5}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results of damping ratio estimates and variances for different methods across frequencies. inconsistency, the pLSCF method's speed may offer advantages in scenarios where quick estimation is necessary, despite its challenges in producing consistent results.