esa-sceva/satcom-chunk-collection huggingface dataset:
# Framework for Fast Experimental Testing of Autonomous Navigation Algorithms
## 6 Experiments
### GNSS/SLAM Fusion Framework Experiments  
To demonstrate our framework versatility, we generated a second application in a different environment. In this case, we replaced the original localization module with the fusion module described in Section 5. Our framework permitted to make this replacement by just changing the corresponding extensible markup language (XML) tag in the launch file of the execution phase without worrying about other nodes and component interactions. The rest of the process to create the application was exactly the same as the one described in the previous section. In this way, we verified the easiness that our framework provides to test new algorithms within a fully operative autonomous  
Figure 10: **(left)** Grid map of the secondary laboratory building, obtained using the architecture shown in Figure 2. **(right)** The actual building and the environment where the initial framework experiments have been carried out.  
navigation application. Concretely, in this case, it would have been very complicated to generate an equivalent application using the navigation stack since it was not prepared for off-map navigation.  
In the rest of this section, we describe and comment on the experiments carried out to test the second application generated using our framework. We tested the new localization module observing how it affected the whole autonomous navigation system. We performed these experiments on the University of Alicante campus (in the area whose grid map is shown in Figure 11) because it was an environment where we can find different scenarios that may affect the localization of our vehicle. For example, there were areas with high trees and buildings--that could cause satellite occlusions affecting the GNSS--and lots of dynamic obstacles, such as pedestrians, electric maintenance cars, or even road vehicles, that can affect the Monte Carlo localization.
# Performance Evaluation of UAV-Enabled LoRa Networks for Disaster Management Applications
### Related Work
The least visited cell in the visibility zone is then selected for exploration and an attractive spring force is computed between the UAV and the center of the cell. [PERSON] et al. [25] study the problem of determining the minimum number of UAVs necessary to provide full coverage to clusters of isolated ground nodes and at the same time maintain connectivity between UAVs. The position of the UAV that covers this subset of clusters (supercluster) is determined by means of a convex minimization problem. The UAV to send to the new computed location is chosen by using a metric that minimizes the total travel distance of UAVs. [PERSON] et al. [26] tackle the more challenging problem of optimally positioning the minimum number of UAVs, taken from the set of all available UAVs, in order to cover a set of targets on the ground, while maintaining the connectivity of the aerial mesh to a ground base station. An evaluation of the model performed by the authors proves that the algorithm always finds an optimal solution in a reasonable amount of time (1000 s). The authors also state that the impact of the connectivity constraint more than doubles, in some circumstances, the number of deployed UAVs. Some other recent studies [27; 28; 29; 30] also investigate the compatibility of UAV and LoRa network for enabling IoT applications. However, one of the main requirements of an LPWAN is its ability to scale to hundreds or even thousands of devices. Early attempts to assessing the scalability of LoRaWAN were performed by resorting to mathematical models. [PERSON] et al. [31] assessed the scalability of a LoRa network in the presence of a single gateway. The authors modeled the LoRaWAN MAC as pure ALOHA and concluded that LoRaWAN can potentially scale to millions of devices in case of end devices generating only intermittent uplink traffic, but most of the devices need to be positioned very close to the gateway. The authors of [22] provided analysis for LoRaWAN. They performed simulation in ns-3 and analyzed the scalability and reliability of such networks. The authors of [32] performed measurements for received signal strength (RSS) for a LoRa network for indoor, suburban and urban environments. They concluded that for vertical transmitting antennas, the radiation pattern of UAV results in stronger RSS levels at the LoRa network.
## 3 Influence Factors of \(R_{s}\)
### Influence of Environmental Factors on \(R_{s}\)
#### 3.1.4 DOM  
The sorption of chemicals onto dissolved organic matter (DOM) was controlled by their hydrophobicity, as characterized by the \(K_{\alpha\alpha}\) values. The partition of organic contaminant into the hydrophobic center of DOM might be through induced dipole interaction [73; 74; 75]. The presence of DOM promoted the sorption of chemicals on membrane in devices and made the mass transfer process difficult through the membrane, thus reducing the accumulation of hydrophobic organic contaminants into passive sampler [76]. The opposite conclusion has also been proposed by [PERSON] et al., where the association of hydrophilic pesticides with DOM limited the sorption extent of pollutants onto the membrane surface in POCIS [77]. Moreover, several studies found that diffusive mass transfer of hydrophobic organic pollutants through the WBL could be enhanced by the presence of DOM [78; 79]. These different results suggested that several factors apart from hydrophobicity influenced the \(R_{\mathrm{s}}\) values, for instance, the sorption of pharmaceuticals to DOM was driven not only by \(K_{\alpha\alpha}\) of compounds, but also by the combined effect of DOM properties, pH value, and chemical properties in the sorption process [80; 81]. In addition, the effect of DOM concentration on the \(R_{\mathrm{s}}\) values has been explored in several studies, where the agreed result was achieved, with little impact on \(R_{\mathrm{s}}\) values by increasing DOM concentration [51; 72; 77].  
Given the complex structure and diverse composition of DOM, the \(R_{\mathrm{s}}\) for different pollutants are significantly diverse. Before using POCIS for monitoring chemicals, researchers should determine the effect of DOM on the device by a laboratory-field combined calibration method to obtain whether the caused error can be ignored.
# Development and Research of a Medium Vertical Dipole Electromagnetic Pulse Simulator
## 3 Design and Construction
### The Vertical Dipole Antenna  
The radiation antenna of our simulator consists of an erection system and a conductive cone, as depicted in Figure 1. The erection system supports and suspends the inverted conical structure of the cone antenna. For this purpose, we use four FRP (Fiber-Reinforced Plastics) columns with a diameter of 200 mm, arranged in a square layout and standing vertically to the ground, as the main body of the erection system. The top crossbeam comprises four FRP pillars with a diameter of 150 mm, overlapped with the four columns perpendicular to the ground to form a stable rectangular doorframe structure. Four dy-nanoelectric windlasses, evenly distributed around the square support and located on the outer extension line at the diagonal of the ground projection of the four FRP columns, are used to operate the suspension system. Four high-strength insulated cables run along the ground grooves and the inside and outside surfaces of the four columns, connecting the windlasses to a frame cone at the top of the antenna. The conductive cone conducts the pulse current fed in from the driver and generates an electromagnetic field that radiates outward along the conical outer surface. To form the conductive cone of the antenna, we enclose 48 metal wires to create a conical shape instead of using a solid metal cone. The frame cone at the top of the antenna comprises two concentric metal rings and numerous evenly distributed FRP brackets, with a cone angle consistent with that of the antenna, to support the wire-mesh cone and maintain its conical structure. To enhance the electrical conductivity of the ground beneath the antenna and within the effective test area, we need to process the ground accordingly. The design layout of the conductive ground is depicted in Figure 3. Starting from the cone vertex of the inverted cone antenna as the center, we level the surface of the circular area with a diameter of 50 m, followed by a hardening of the cement within the area with a diameter of 25 m, in order to achieve the desired effect.  
Figure 2: The developed dipole EMP simulator. **(a)** Voltage feed-in over the ground. **(b)** Voltage feed-in under the ground.
# An Overview of Cube-Satellite Propulsion Technologies and Trends
## 7 Hall Effect Propulsion/Hall Thrusters
### Design Considerations and Technologies
It was found from a study that, for small Hall thrusters, the propellant mass flow rate and the applied power were proportional to the channel length, while the magnetic field strength was inversely proportional to the channel length. In other words, as long as the power of a larger Hall thruster is available, the mass flow rate of propellant, strength of applied magnetic field and channel length can be determined [88]. Table 6 provides the summary of the surveyed Hall thrusters and their performance parameters. None of the listed engines have a CubeSat heritage, however one of them has flown on two bigger satellite missions as a secondary propulsion system.
# Quantifying the Training and Match-Play External and Internal Load of Elite Gaelic Football Players
## 2 Materials and Methods
### Training Load Analysis  
Internal training load data were obtained through subjective means via the RPE-based method (Kal  
events [10]. Players RPE was individually collected through the utilization of a custom-designed application on a portable tablet (iPad, Apple Inc, Cupertino, California, USA). Each player selected his RPE rating by touching the respective score on the tablet, which was then automatically saved under the player's profile. This method helped minimize factors that may influence a player's RPE rating, such as peer pressure and replicating other players' ratings [9]. During the observational period, all players wore the same GPS unit (4 Hz, VX Sport, Lower Hutt, New Zealand) for each training and match sessions to minimize interunit error [3; 4; 5; 6; 7]. The device was activated, and the satellite lock established for a minimum of 15 min before the commencement of each match [22]. GPS technology is a valid and reliable way of measuring distance and movement speeds in a range of high-speed, intermittent, contact, and noncontact sports [12]. The number of satellites for GPS was satisfactory during all competitive match-play events: range: 10-15 with an average of 12.3 \(\pm\) 3 satellites per training and match-play activity, respectively. The horizontal dilution of position (HDOP) which reflects the geometrical arrangement of the satellites and is related to both the accuracy and quality of the signal was not collected, which is a limitation of the current study. Specific external training load parameters obtained from GPS include total distance (m); relative total distance (m\(\cdot\)min\({}^{-1}\)); high-speed running (m; \(\geq\)17.1 km\(\cdot\)h\({}^{-1}\)) (HSR); very high-speed running (m; \(\geq\)19.8 km\(\cdot\)h\({}^{-1}\)) (VHSR); sprint distance (m; \(\geq\)22 km\(\cdot\)h\({}^{-1}\)); accelerations (n; \(\geq\)3 m\(\cdot\)s\({}^{-2}\)); high-power meters (m; \(\geq\)25 W\(\cdot\)kg\({}^{-1}\)); average metabolic power (W\(\cdot\)kg\({}^{-1}\)) [2; 3; 4; 5; 6; 7]. Each player wore the device inside a custom-made vest supplied by the manufacturer across the upper back between the left and right scapulae.
# Study on the Effect Mechanism of MRD to Rotor System
## 4 Conclusions  
To study the effect mechanism of MRD to a rotor system, a model of MRD based on bilinear constitutive law is built and introduced to a Jeffcott rotor. A general coupling system model of MRD-bearing-rotor with supporting of squirrel cage is developed using the finite element method. The mechanical properties of MRD are analyzed in detail, and the effect mechanism is discovered. Some conclusions are summarized as follows:  
1. The change of the yield surface position that will cause the change of flowing space is an important mechanical response of MRD to the applied current. With the increase of the yield stress, the position of the yield surface moves and the region of unyielding is gradually enlarged. When the yield stress hits a certain value, the flow field is saturated with it, and the yield surface is fixed at a certain position;
2. With or without applying current, the mechanical properties of MRD are different. When the current is applied, the azimuth of the maximum film pressure moves and the film pressure changes abruptly at the positions of film formation and fracture. With the increase of the current, the film pressure increases obviously and the azimuth of the maximum film pressure remains constant;
3. Eccentricity ratio and current have significant influences on the equivalent stiffness and damping coefficients of MRD. With the increase of the eccentricity or current, the equivalent stiffness and damping coefficients increase. The bigger the eccentricity ratio, the larger the increments of the equivalent stiffness and damping coefficients;
4. MRD mainly affects the dynamic characteristics of the rotor system through its damping and stiffness effects, and the two effects are coupled. With the increase of the current, MRD first affects the dynamic characteristics of the rotor system mainly through its damping effect, which has an obvious suppression on the vibration of the rotor system at the critical speed. When the current increases to a certain value, the stiffness effect of MRD plays a major role, which limits the oil  
Figure 13: Dynamic responses of the rotor system under several currents. (**a**) Orbit at critical speed, (**b**) spectrogram at critical speed and (**c**) Poincaré map at critical speed.  
film to be squeezed and the damping effect is weakened. In addition, in the case of the large core volume and large deflection, the oil film is too thin and takes nonlinearities, resulting in instability of the rotor system.  
[PERSON] developed the MRD model and conducted the analyses; [PERSON] contributed analysis tools; [PERSON] wrote and revised the paper; [PERSON] developed the baseline rotor model.  
This work is supported by the National Natural Science Foundation of China (No.51705355) and the Fundamental Research Funds for the Central Universities of China (No.3122018D015).  
The authors declare no conflict of interest.
# High Performance GAA SNWT with a Triangular Cross Section: Simulation and Experiments
## 2 Simulation
### Simulation Results  
Figure 2a-c shows the trends of Vth, SS, and DIBL as a function of gate length in different cross-sectional GAA SNWTs. From Figure 2a, it can be noticed that the triangular devices have the lowest Vth roll-off, whether in the linear region or the saturation region. Here, the Vth values of long channel devices with three cross-sectional shapes differ from each other, which is mainly due to the different work functions of the gate material. For the triangular, circular, and square devices, they are 4.37 eV, 4.53 eV, and 4.60 eV, respectively. This is to maintain the same off-state current of 100 nA/um when comparing the on-state current of short channel devices. In addition, it can also be found from Figure 2b,c that the triangular devices also have smaller DIBL and SS under the same gate length condition. Even for GAA SNWTs with the same linewidth of 16 nm, only the triangular devices can successfully reduce the gate length to 16 nm under the requirement of SS \(<\) 67 mV/dec, which met IRDS 2017 requirements on the 5 nm technology node [8], as shown in Figure 2d. Additionally, compared to the worst quadratic GAA SNWTs, the gate length of triangular one is reduced by approximately 8 nm.  
The electrostatic controllability and short channel effects affect not only static power consumption, but also driving capability. Given the fixed off-state current, SCE determines the threshold voltage level, which will impact the device's overdrive voltage--Vgg-Vth, and hence on-state current. Figure 3 shows the relationship between the off-state current and the on-state current for GAA SNWTs with three cross-sections under different gate length conditions. From Figure 3, it is noticed that the triangular devices have the best on/off ratio. Under the same off-state current of 100 nA/um, due to better electrostatic control capability and SCE immunity, the triangular devices have a higher on-state current, reaching 940 uA/um, which is nearly 10% higher than that of the circular devices, and nearly 36% higher than quadratic ones.  
Figure 2: **(a–c)** The trend of Vth, SS, and DIBL for different cross-sectional shapes of GAA SNWTs as a function of gate length; **(d)** The ability to scale down GAA FETs with different cross-sections.
# A Tale of Many Networks: Splitting and Merging of Chord-like Overlays in Partitioned Networks
## 2 Related Work
### Chord-Zip  
The authors of Chord-Zip [6; 14] suggest that the local information at two nodes from different Chord rings is sufficient to merge the two Chord rings. Each node is able to rearrange its locality without global knowledge. In cases where an initiator node becomes aware of any other contact node in another ring, it will be able to start a lookup to its successor in the other ring (denoted as alternative successor). Thereafter, the initiator node starts the merging procedure by forwarding its original routing information to the alternative successor and asks the alternative successor for its predecessor, its successor list, its finger table, and for the part of the identifier space it will be responsible for after the merger. Upon receiving the information from the initiator, the alternative successor responds by sending the requested information to the initiator. Simultaneously, the alternative successor forwards the merging process to the next contact node in the other ring, requesting successor list, predecessor, finger table, and range of responsibility. Obtaining all information from its neighbors, a node updates its routing links by using the most fitting entries in its routing table. The merging process is repeated by every node until the merger token arrives back at the initiator node. Finally, the initiator node combines its successor list and its finger table with those information it obtained from the alternative successor.  
The execution time of the merger, which consists of one Chord join operation and the merge signal, can be improved by determining the multiple initiator instances that start the merger algorithm simultaneously. Further, initiator nodes block bypassing signals to terminate the algorithm.  
For parallelization, the authors introduce two methods. First, nodes in both rings could start the merger algorithm concurrently. Secondly, some nodes could have the privilege of appointing further initiator nodes (e.g., finger entries).  
Since the authors of Chord-Zip do not present lines of code for their algorithm, we interpret the Chord-Zip algorithm in the following way, as described in Figure 3. First, a lookup in the other ring is started to obtain the alternative successor. Thereafter, the merging algorithm is started by sending a ZIPING message containing the initiator's routing information to the alternative successor. The receiver of a ZIPING message answers with a ZIPPONG message containing its own routing information. The receiver of a ZIPPONG message on the other hand updates its routing table with the routing information obtained from its neighbors. The initiator nodes stop the merging algorithm upon receiving a ZIPPING message. In the evaluation of this paper, we show that this Chord-Zip algorithm does not merge overlays reliably.
# A Survey on Pump and Dump Detection in the Cryptocurrency Market Using Machine Learning
## 4 Findings
### Semi-Supervised Approach  
Since there is a large number of telegram messages and tweets, manually labeling these messages to find whether they are pump related or not is time-consuming and expensive. To address this issue, some studies deployed a semi-supervised approach to label the messages. They manually labeled some of the messages, and then they trained a model to predict the labels; they used this trained model to label all the messages. [PERSON] et al. [40] combined information from Twitter and Telegram to automatically detect ongoing pump operations and predict their success. They labeled 1557 messages and trained an SVM to label their data. They used three kinds of data for detecting the pump attempts: Telegram data which contain 195,576 Telegram messages; Twitter data which includes 3,760,831 tweets; and market data which are collected from the CoinMarketCap website [41]. They trained two binary classification models for detecting pump attempts from Telegram messages and to determine whether the target price would be achieved or not. The results of their ML models showed reasonable accuracy in detecting unfolding attacks and predicting the achievement of price targets. They also found that these scams are often accompanied by an increase in bot activities on Twitter.  
On the other hand, [PERSON] et al. [42] labeled 5050 messages and used RF and LR models to label the data. They trained DL models to classify the input data and determine whether the input was pump-related or not. They focused on predicting the pump probability of coins listed in a specific exchange before the scheduled pump times. The authors analyzed 709 P&D events organized in Telegram from January 2019 to January 2022 and identified interesting patterns, such as intra-channel homogeneity and inter-channel heterogeneity among pumped coins. Inspired by these observations, they developed a novel sequence-based neural network called SNN which mainly consists of three parts: an embedding layer that is used to handle categorical values in the input sequence and reduce sparsity and dimensionality by converting the sequence into a dense vector representation; positional attention that is used to find the sequential patterns in the input sequence and capture skip-correlations; and a multi-layer perceptron containing several fully connected layers to predict the final pump probability. Extensive experiments validated the effectiveness and generalizability of their proposed methods. Overall, their data science pipeline and SNN model showed promising results, indicating their suitability for real-world scenarios.
## 2 Materials and Methods
### Sample Collection and Measurements  
#### 2.3.1 Determination of Soil Water Content  
The surface and sub-surface undisturbed soil samples from different treatments were sampled at a crop maturity stage for the determination of gravimetric soil water content (SWC). Five points were randomly selected in each test plot in the shape of \"S\"; the removal of aboveground plants and surface litter and soil drills with a diameter of 5 cm were used to collect 0-10, 10-20, 20-40, 40-60, and 60-100 cm soil layer soil samples [30]; the same soil layer soil was constituted with a mixed soil sample, debris was removed, and it was put in a Ziplock bag and placed in a sample box with an ice bag for low-temperature transportation [31]. These samples were taken back to the laboratory for the determination of soil indicators. An aluminum box drying method was used to determine SWC. The empty aluminum box was weighed first, and the fresh soil sample was then put in the aluminum box, which was weighed and transferred to an oven. After drying to a constant weight at 105-110 \({}^{\circ}\)C, the weight of the dry soil was determined, and the percentage of water weight was then calculated to obtain the SWC [18].