esa-sceva/satcom-chunk-collection huggingface dataset:
# Future Directions for Electric Propulsion Research
## 4 Challenges for Electric Propulsion Development
### High-Power Thrusters
#### 4.3.3 Magnetoplasmadynamic Thrusters  
Similar to high-power gridded ion thrusters, magnetoplasmadynamic (MPD) thrusters are an existing electric propulsion technology that have long since been designed and tested to high power in ground facilities and have even been fired in orbit. In fact, several devices were pulsed at up to 1 MW three decades ago [117; 118], and a 1 kW class unit flew on the Japanese Space Flyer Unit spacecraft not long after [119]. These devices establish an arc discharge between concentric electrodes; the Lorentz force then accelerates the arc plasma along the electrodes and out of the device. The 100 kW SX3 applied field MPD developed by the Institute of Space Systems (IRS) is shown as an example in Figure 16. This technology has been studied for decades, e.g., [120; 121; 122], with gradual improvements in efficiency--in excess of 60% [123] and \(I_{sp}\) close to 7000 s [124]--and various propellants. For this reason, they have traveled slightly up their s-curve in Figure 13 and may inflect in the near future, but there are formidable remaining challenges for this technology.  
The main challenge for MPDs is simply that their performance is poor at power levels \(<\)100 kW. By the same token, any high-performance designs are currently impractical due to the lack of appropriate in-space power systems: high-current, high-power supplies that allow for high-frequency operation. Research into applied field MPDs has indicated that high thrust efficiency can still be achieved at lower power levels, but at the cost of higher mass-to-power [126]. Additionally, the limited lifetime of MPDs may make them less competitive against other forms of electric propulsion, especially for most laboratory designs of middling efficiency that are currently tested in the 20-100 kW range. Recent advances at the University of Stuttgart suggest that different operating modes and the use of a LaB\({}_{6}\) cathode and regulated voltage supply may simplify the power processing electronics and extend the lifetime of these devices [123].
## 4 Problem Definition
On the other hand, distributed reinforcement learning and game-theoretic algorithms offer independent learning with increased communication overhead and computational complexity. However, these methods compromise scalability at the expense of additional communication overhead and lack adaptability in dynamic environments. We model this problem as multi-armed bandits and combine the cooperative, independent Q-learning approach by leveraging shared rewards with environmental signals. In our model, slot selection with cooperation is inspired by Independent Q-Learning, aiming to balance individual optimization with cooperative behavior. Our proposed reward structure guides agents towards cooperation while maintaining independent learning at each node. Nodes can determine their slots to transmit packets, incorporating environmental conditions to determine the optimal timing for packet transmission or reverting to energy harvesting mode. In our model, we used the stochastic piezoelectric harvester, and the following assumptions were made:  
* The statistical characteristic of all random quantities (flow velocity, voltage peaks, etc.) is known by observation and experiment [11; 39]. * Harvested power in time slots is independent and identically distributed. * As a well-known practice, we employ two different MAC methods on the low density (size of inter-cluster nodes) and high density (size of intra-cluster nodes) settings in clustered network topology. Namely, the TDMA MAC protocol for intra-cluster communication and the CSMA MAC protocol for determining the average power consumption of cluster heads in inter-cluster communication.
## 3 Discussion
### Charge and Discharge at Low Power  
In this case study, the initial voltage of the cell is assumed to be 2.7 V. A discharge is followed by a charge. The former occurs at 20 W for 100 s, whereas the latter takes place at 40 W for 50 s. These values are below 4% of the maximum allowed power indicated by the manufacturer. Table 2 shows the values of the temperature at both the beginning and end of each time interval, as well as the internal voltage at the beginning of each process and the values of the constants \(\mathrm{g_{1(0)}}\) (\(\mathrm{g_{1}(t)}\) at t = 0), \(\mathrm{k_{\mathrm{\theta}1}}\), and \(\mathrm{k_{\mathrm{\theta}2}}\).  
Figure 5 shows the temperature of the cell obtained every 5 s, by using both the formulas proposed in Section 2.3, and the approximate equations described in [56]. As can be concluded from the graph, the agreement between both formulations is absolute during the discharge, whereas a minor discrepancy can be observed during the charge. Therefore, the approximate equations practically provide the same results as those given by the proposed formulas, thus proving the former are proper for charging and discharging processes at low or moderate power values, as stated in [56].
## 3 Results
### Characteristics of the Included Studies  
A summary of the characteristics of the included studies is presented in Table 2. Among the 21 included articles in this qualitative analysis, one was an RCT [18], fourteen were retrospective [19; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39], and six were prospective cohort studies [7; 21; 40; 41; 42; 43]. Six investigations only included patients who underwent NSRME [27; 29; 30; 31; 32; 40], eleven studies presented patients who experienced SARME [7; 18; 19; 21; 35; 36; 37; 38; 39; 42; 43], and four studies reported outcomes from both NSRME and SARME procedures [28; 33; 34; 41].  
A total of 901 patients were included among all of the selected articles. Of these, 464 patients underwent SARME procedures, 289 experienced NSRME, 33 were treated with non-surgical slow maxillary expansion, and 115 served as controls without any maxillary expansion performed. The mean ages across all of the studies ranged between 13.2 and 31.4 years old, representing patients at diverse levels of skeletal maturity.  
The assessment of periodontal outcomes varied between clinical and radiographic measurements. Eight studies collected clinical measurements from periodontal exams [7; 19; 21; 27; 28; 34; 36; 42]. Conversely, nine studies measured radiographic outcomes via cone-beam computed tomography (CBCT) [18; 30; 31; 32; 33; 34; 38; 39; 42], one used multi-detector computed tomography [35], and two used intraoral radiographs [7; 36]. Ultimately, seven investigations obtained measurements from stone cast models [7; 28; 29; 37; 40; 41; 43] and two through intraoral photographs [28; 34].  
Regarding the type of expanders used for the treatment of transverse maxillary deficiency, a total of twelve studies used Hyrax-type tooth-borne maxillary expanders [18; 19; 21; 28; 30; 31; 35; 37; 38; 39; 42; 43], six studies employed bone-borne appliances [7; 19; 28; 34; 35; 36], four studies used hybrid tooth-bone-borne devices [18; 32; 33; 34], two studies used C-type tissue-bone-borne devices [31; 32], and four used a Haas-type tissue-tooth-borne appliance [27; 29; 40; 41].
# Seeking a Definition of Digital Twins for Construction and Infrastructure Management
## 3 Digital Twins Current State of the Art
### Digital Twins in Other Fields  
In the field of medical uses, DTs are used in various ways, such as the monitoring of physical activity [38] simulations of viral infections [39], remote surgery [40] and health care management [41]. In [41], the concept of human digital twins (HDTs) is presented with an emphasis on security and ethics. The purpose of HDTs is to expose the human body in cyberspace by making use of information from wearables, mobiles apps, and medical records that change through web services. Another challenge comes from the trait's complexity, which is influenced by genetic factors, like culture and heredity, and considers interdependence among other issues. The athlete specific HDTs discussed in [38] have been developed to monitor parameters, such as heartbeats and activity levels, using the Smart Fit app for trainers and educators. To analyse data, ML or DL algorithms can be used, but difficulties include the size of data being handled, at the same time, sorting both huge volumes of data out within processing time limits which have since been dealt with by incremental learning. [PERSON] et al. [40] focus on a hierarchical multi-scale DT modelling framework for simulating host responses to viral infections over a range of scales; it is essential for testing models against sensor/medical data. Expert validation must be undertaken because understanding these phenomena is still limited.  
In the automotive sector, while DT concepts are increasingly used, focus remains on manufacturing processes and prototype testing. The DT is pivotal for data-driven manufacturing [42]. Benefits include productivity boosts, reduced complexity, time and cost savings, and quality improvements [43]. DTs facilitate product development and optimisation by providing unique insights [43]. Various DT configurations impact different stages of a vehicle's lifecycle, from conceptual design to end-of-life considerations. [PERSON] [44] introduces an advanced X-in-the-Loop framework integrating DTs and the IoT to connect physical and virtual vehicle representations for testing. This framework is applied in diverse test environments, including real-time vehicle simulation, urban testing for automated cars, and connectivity platforms [44]. Mixed reality enhances reproducibility, flexibility, scalability, cost efficiency, and realistic simulation [44]. Key technologies include simulation tools, like CarMaker VTD, sensors, such as LIDAR and RADAR, GPS, IMU, CAN bus, and cameras [44].  
ISO/IEC 30173:2023 [45] provides horizontal definitions for the digital twin concept, valid for any sector. It is conceived as a digital entity defined by a set of properties and/or behaviours representing a physical or nonphysical entity, which has data connections to synchronise the physical and digital states. The definitions provided in the international standard are used in CEN/TC 442/WG 9 to create a set of definitions applicable to the built environment.
# Application of Bayesian Neural Network (BNN) for the Prediction of Blast-Induced Ground Vibration
## 3 Proposed Artificial Neural Network (ANN) Model
### Evaluation Metrics
#### 3.2.3 Mean Squared Error (MSE)  
The MSE is a common regression model evaluation approach (Equation (13)). It averages the squared differences between predicted and actual values. The mean squared error is calculated by summing the squared differences between predicted and actual values and dividing them by the number of observations. The model predicts the target variable more successfully with a lower MSE. Therefore, they were considered when evaluating the findings. Optimization- and gradient-based techniques benefit from MSEs differentiability.  
\[\text{MSE}=\frac{1}{m}\underset{i=1}{\overset{m}{\sum}}\left(y_{i}-\hat{y} _{i}\right)^{2} \tag{13}\]  
where \(MSE\) = mean squared error; \(m\) = total number of observations; \(y_{i}\) = actual observations time series \(y\); and \(\hat{y}_{i}\) = estimated time series of \(y\).
# Stochastic Model Driven Performance and Availability Planning for a Mobile Edge Computing System
## 4 Evaluation of MEC Performance
### Refined Model with Absorbing State  
System administrators who want to use a MEC architecture should be aware of when their applications are most likely to finish execution. Cumulative Distribution Functions (CDFs) may indicate such a moment through the maximum probability of absorption. CDFs are associated with a specific probability distribution. In this work, the probability distribution is related to the probability of finishing the application execution within a specified time. It is obtained through transient evaluation, generating probabilities with time tending to one value t. In other words, developers compute the probability of absorption in [0, t), through transient evaluation, where F (t) approaches 1.  
CDFs indicate the maximum probability of an application's processing to be completed within a given time interval. In this work, the absorbing state is reached when the model is in the FINISH state. For a better understanding of time-dependent metrics, it is necessary to define the difference between transient state and absorbing one. Transient states are defined as temporary states. In other words, when the system leaves a transient state, there is a likelihood of never coming back to it again. On the other hand, an absorbing state is a state that when the system reaches it, there is no way out. Figure 8 shows the adaptation we made in our SPN model presented previously to calculate CDFs.  
Three changes were made: _(a)_ an absorbing state place (named Finish) was added in the right part of the model, indicating that when the requests reach this place, such requests will not change state; _(b)_ in the Admission block, the feedback loop (\(T0\to P\_Arrival\)) has been withdrawn, indicating that new requests will not be generated unmistakably; and _(c)_ there is a new parameter called BATCH (at place P_Arrival) that represents the number of jobs (tokens) that will be processed. The CDF calculates the probability of these jobs to complete the application processing at a given time and in a specific time interval.  
Figure 7: Discard Probability.
## 4 Application to a Stock of Bridges with Current Verification Loads
The same procedure was repeated considering a dynamic amplification factor \(\Phi\) to increase the applied loads:  
\[F=g+\Phi\cdot\alpha\cdot q \tag{15}\]  
The value of the dynamic amplification factor \(\Phi\) depends on the code, and on the length of the arch, as depicted in Figure 10. In detail, constant values were assumed for the design codes, notably \(\Phi=1\) for the 1925 and 1926 loads and \(\Phi=1.25\) for the 1945A and 1945B loads, whilst \(\Phi\) varied with the length for the line loads B2, C3, and D4. The dynamic amplification factors are higher for the B2 and C3 lines, since they have higher associated design velocities compared to the D4 line. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Codes**}} & \multicolumn{8}{c}{**Load Rating Factors \(V\)**} \\ \cline{2-9}  & \multicolumn{8}{c}{**Arch Bridge Length L (m)**} \\ \cline{2-9}  & **5** & **10** & **15** & **20** & **25** & **30** & **40** & **50** \\ \hline
1925 vs. B2 & 0.84 & 1.30 & 1.34 & 1.36 & 1.30 & 1.33 & 1.25 & 1.26 \\
1925 vs. C3 & 0.75 & 1.17 & 1.2 & 1.22 & 1.18 & 1.17 & 1.13 & 1.11 \\
1925 vs. D4 & 0.67 & 1.04 & 1.07 & 1.08 & 1.04 & 1.06 & 1.00 & 1.01 \\
1926 vs. B2 & 0.49 & 0.67 & 0.71 & 0.78 & 0.81 & 0.72 & 0.39 & 0.16 \\
1926 vs. C3 & 0.43 & 0.6 & 0.64 & 0.70 & 0.73 & 0.65 & 0.35 & 0.15 \\
1926 vs. D4 & 0.39 & 0.53 & 0.57 & 0.62 & 0.67 & 0.57 & 0.31 & 0.15 \\
1945A vs. B2 & 0.97 & 1.41 & 1.66 & 1.94 & 2.39 & 2.20 & 2.28 & 2.09 \\
1945A vs. C3 & 0.88 & 1.27 & 1.50 & 1.75 & 2.08 & 1.84 & 2.05 & 1.88 \\
1945A vs. D4 & 0.78 & 1.13 & 1.33 & 1.55 & 1.91 & 1.78 & 1.82 & 1.67 \\
1945B vs. B2 & 0.84 & 1.31 & 1.36 & 1.47 & 1.52 & 1.44 & 1.45 & 1.39 \\
1945B vs. C3 & 0.75 & 1.18 & 1.21 & 1.32 & 1.35 & 1.27 & 1.31 & 1.24 \\
1945B vs. D4 & 0.67 & 1.05 & 1.08 & 1.18 & 1.22 & 1.15 & 1.16 & 1.11 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Load Rating Factors \(V\) for the 1925, 1926, 1945A, and 1945B design loads, and the B2, C3, and D4 lines. Figure 10: Dynamic amplification factors applied to different loads. It is important to notice that for the dynamic amplification factors used in this analysis, it was assumed that, for the 1925 and 1926 design codes, no dynamic amplification was considered at the design stage. The minimum reserve capacities obtained from the analyses are summarized in Table 4 for each combination of design and verification loads.
# Satellite IoT Edge Intelligent Computing: A Research on Architecture
## 2 Related Work  
### Related Research on Satellite Internet of Things  
The role of satellites in the IoT is irreplaceable and related technologies of satellite IoT have become one of the hot research topics. In [4], the authors outline the IoT architecture based on the LEO satellite constellation, including LEO satellite constellation structure, efficient spectrum allocation, heterogeneous networks compatibility, and access and routing protocols. The importance of using satellite communication systems to the Internet of remote Things (IoRT) is described in [5]. The research includes MAC protocols for satellite-routed sensor networks, efficient IPv6 support, quality of service (QoS) management, heterogeneous networks interoperability, and group-based communications. Article [19] introduces SDN/NFV and microsatellite technology into the space satellite IoT and evaluates the impact of different orbital configurations and carrier frequencies on data rates, link latencies, and next-hop availability and access durations.
# Analysis and Experimental Test of Electrical Characteristics on Bonding Wire
## 3 Frequency Domain Simulation
### Influence of Bonding Height on S Parameter of Bonding Wire  
The height of the bonding wire and the arch has a great influence on the electrical properties of the bonding wire. The signal transmission path also increases because of the rise of the height, which exacerbates the signal transmission loss. Keeping the other parameters unchanged, the bonding height of H1 was chosen as the variable. The bonding height scanning ranged from 210 \(\upmu\)m to 310 \(\upmu\)m, and the interval was 20 \(\upmu\)m: 210 \(\upmu\)m, 230 \(\upmu\)m, 250 \(\upmu\)m, 270 \(\upmu\)m, 290 \(\upmu\)m and 310 \(\upmu\)m. The sweep frequency ranged from 1 MHz to 20 GHz. The results of S11 and S21 with the bonding height and frequency of the bonding wire are shown in Figure 9a,b ranging from 1 MHz to 20 GHz.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Span/\(\upmu\)m** & **2500** & **3000** & **3500** & **4000** & **4500** & **5000** \\ \hline Min S21 (Insertion Loss)/dB & \(-\)8.01 & \(-\)8.37 & \(-\)8.69 & \(-\)8.71 & \(-\)8.96 & \(-\)9.03 \\ Corresponding frequency/GHz & 25.12 & 22.54 & 19.82 & 17.33 & 15.67 & 14.33 \\ Passing signal/incoming signal/\% & 39.76 & 38.15 & 36.77 & 36.69 & 35.65 & 35.36 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Comparison of S21 extremum under different span.  
Figure 8: **(a)** S11 of bonding wire with different span; **(b)** S21 of bonding wire with different span.  
In order to get clear graph and accurate data, the S11 log coordinate was intercepted from three to 10 GHz in Figure 9a. With the increase of frequency, the return loss also increased. Furthermore, the wire with a smaller bonding height had better electrical performance. For example, when the longitudinal coordinate was \(-3\) dB, the corresponding abscissa of bonding wire with height 210 \(\upmu\)m was 4.69 GHz, and the abscissa of bonding wire with 310 \(\upmu\)m is 4.40 GHz. Figure 9b is the logarithmic coordinate graph of insertion loss S21. The S21 extreme points of different bonding height are extracted in Table 5. When the bonding height was 210 \(\upmu\)m, the S21 had the minimum value of \(-8.61\) dB at 17.58 GHz, and the ratio of passing with incoming signal was 37.11%. Compared with the case of 310 \(\upmu\)m, the modulus of S21 increased by 0.41 dB (about 4.8%). The signal transmission quality also rises by 1.71%. Although the increase of bonding height will cause the rise of the whole wire length and a decrease in signal quality, the connection height cannot be over reduced. A low height connection will increase stress of bonding wire, making the solder joint unstable and causing other mechanical problems.
## 2 Materials and Methods
### Experiment to obtain the IRI
The image set was loaded into the software where using SfM algorithms and photogrammetric techniques, it manages to recognize points that are in more than one image and thus, in conjunction with the respective GPS location that each image has, the information contained in each of them is triangulated to define the location in the model of each recognized mooring point. According to the positioning system adopted, the model was oriented in the global GPS network, in addition to being assigned a scale. Once the virtual model was successfully created, reports were obtained that quantify and diagnose the quality of the reconstruction. The format of the generated output file is 3 MX. After the virtual model was created, the 3 MX file is imported using analysis software called Bentley power GEOPAK V8i to generate a 3D \"seed file\" in DGN format. Later, the model was modified so that it is recognized as a surface element. Then, from the 3D seed file, a 2D seed file is generated so that it is possible to interact with the previously generated surface so that by drawing a longitudinal axis over the path, that axis obtains information regarding the height of each point, thus achieving the longitudinal profile of the path. Subsequently, a report was exported, which contains a list with two columns, the first of which corresponds to the spacing considered and the second to each point's height. To corroborate and compare the data obtained, an official certificate of testing No. 0778/19111 of IRI measurement was available by the Directorate of Roads of the Ministry of Public Works of Chile, carried out on the ROL F-190 route between kilometers 19,600 and 19,800. The equipment that was used to carry out this test was a MLP profilometer. Two methodologies were used for the calculation of the IRI; the first is based on simulating the operation of the MERLIN equipment and its statistical logic to form a histogram containing the number of times a certain deformation value is presented in each one-meter interval. For this, it was considered to measure the difference between the dimensions obtained in the profile versus imaginary dimensions obtained by taking the average of the two adjacent dimensions consecutively along the track. For these conditions, the rougher the simulation, the greater the differences between the actual and the imaginary dimensions. The second methodology is based on using a longitudinal profile that has one centimeter spacing between dimensions. The dimension report is imported into a computational program that allows you to simulate the Quarter Car Model on the profile entered and thus obtain the IRI based on the standards and parameters set by the FHWA/LTPP.