esa-sceva/satcom-chunk-collection huggingface dataset:
# An Intelligent Condition Monitoring Approach for
## 2 Theoretical Background
### Wavelet Packet Transform  
The wavelet packet transform (WPT) (a further development of WT) is an adaptive time-frequency analysis method for data from nonlinear and non-stationary signals. It can improve the signal's time-frequency resolution by decomposing the frequency bands into several levels adaptively, especially high-frequency bands that WT cannot finely decompose [37]. Figure 1 illustrates the wavelet packet decomposition.  
The decomposition has the following relations:  
\[S=AAA_{3}+DAA_{3}+ADA_{3}+DDA_{3}+AAD_{3}+DAD_{3}+ADD_{3}+DDD_{3}, \tag{1}\]  
where \(A\) stands for low frequency, \(D\) for high frequency, and the index for the level of the wavelet packet decomposition.  
Let \(W_{j}^{n}\) be an orthogonal wavelet subspace, \(f_{j}^{n}(t)\in W_{j}^{n}\) an orthonormal wavelet packet progression, and \(d_{l}^{j,n}\) the wavelet packet coefficient. Then, \(f_{j}^{n}(t)\) is:  
\[f_{j}^{n}(t)=\sum\limits_{l\in Z}d_{l}^{j,n}\omega_{n}(2^{j}t-l). \tag{2}\]  
The wavelet packet decomposition algorithm can be expressed as:  
\[\left\{\begin{array}{l}d_{l}^{j,2n}=\sum\limits_{k\in Z}a_{k-2l}d_{k}^{j+1,n },\\ d_{l}^{j,2n+1}=\sum\limits_{k\in Z}b_{k-2l}d_{k}^{j+1,n},\end{array}\right. \tag{3}\]  
and the wavelet packet reconstruction algorithm is:  
\[d_{l}^{j+1,n}=\sum\limits_{k\in Z}(a_{l-2k}d_{k}^{j,2n}+b_{l-2k}d_{k}^{j,2n+1}), \tag{4}\]  
Figure 1: Map of wavelet packet decomposition.  
where \(a_{k-2l}\) and \(a_{l-2k}\) are the coefficients of low-pass filters, \(b_{k-2l}\) and \(b_{l-2k}\) the coefficients of high-pass filters, and \(n\) the level of decomposition.
## 4 Materials and Methods
### System Construction  
We partially implemented the proposed architecture to preliminarily validate it. First, we used NodeMCU as the microcontroller-based development board and the SIM 900 GSM/GPRS shield as the wireless networking module for the realization of the IoT-based hardware platform layer.  
Second, we used Amazon's AWS IoT Core, AWS IoT Analytics and S3 services to realize the IoT message hub, IoT data analytics and data storage service components of the cloud-computing platform layer of the proposed architecture. Likewise, we used Jupyter Notebook documents to implement machine-learning algorithms for predictive analytics in Python, being able to run the resulting models on AWS IoT analytics thanks to the integration of this cloud service with the Jupyter Notebook data science tool.
# Reduced-Complexity Tracking Algorithms on Chip for Real-Time Location Estimation
## 4 The Proposed Filtering Algorithm Based on Chip  
Referring to several references [17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35], the proposed filtering algorithm is designed. KF has very complex matrix inversion and matrix calculation, and this algorithm can greatly reduce the complexity of the calculation. A proposed tracking approach is based on the KF approach with steady state. According to the KF algorithm, the positioning algorithm often requires a large number of iterations, as shown in Equation (6). In each iteration, the calculation of KG is very large and complicated, no matter in software operations or hardware cost is a big consumption. Therefore, as shown in Figure 4, it is found that KG will stabilize after several iterations, and then replace KG in Equation (6) with \(\alpha\) and \(\beta\), K is the coefficient gain matrix with \(\alpha\) and \(\beta\) and chooses DKF or PKF to become DKF and PKF filtering algorithm. From now on, iterations began to use decision mode. This algorithm can significantly reduce computing resources and processing time for chips.
# VAE-Based Real-Time Anomaly Detection Approach for Enhanced V2X Communication Security
## 3 Proposed Methodology
### Real-Time Anomaly Detection Model
It consists of transposed convolutional layers to upsample the latent representation back to its original dimensions. The decoder reconstructs normal BSM patterns and evaluates the reconstruction quality to identify anomalies. A sigmoid activation function is applied at the output layer to constrain the reconstructed data within the normalized range of [0, 1]. The model utilizes the Kullback-Leibler (KL) Divergence term to regularize the latent distribution towards a standard Gaussian, while the Mean Squared Error is used for the reconstruction loss. The total loss combines these components using a configurable parameter (beta), balancing between accurate reconstruction and latent space regularization [32].
## 4 Actuation System
### Finite Element Modeling of the Actuation System
The loads have been computed for all hinges shown in Figure 15. As an example, for the computed loads, the required actuation forces for the different load conditions are depicted in Figure 18.  
In this figure, it is shown that the highest actuation force (5.8 kN) is required in step 4 (S5 with pressure loads), even though the major part of the actuation force is due to the stiffness of the MLE (5.2 kN in step 3: S5 without pressure loads) and not to the pressure loads. The required power of the actuator depends linearly on the desired actuation speed. Hence, the choice of the velocity requirement has a major impact on the weight of the actuator. The transition between high lift and clean wing configuration is typically a slow movement that may take several seconds. The actuation stroke for morphing from aerofoil S5 to S4 is 110 mm. Assuming an actuation speed of 22 mm/s (corresponding to a deployment time of 5 s) and an actuator efficiency of 90% the required power of the electromechanical actuator is 142 W (without power reserve) for the MLE section of 1.3 m. The load cycles of all kinematic components have been computed by this FE model, and the components have been dimensioned accordingly.
## 5 Local Pre-Rerouting Algorithm  
### Algorithm Overview  
The routing algorithm proposed in this article is based on the routing strategy of virtual topology [6]. The virtual topology switching period is \(T\). The network topology is considered unchanged in each topology cycle. The propagation delay in the link needs to be updated between different topologies. This information is stored in the space router. No  
Figure 5: (**a**) Number of intra-plane ISL sun outages of different duration; (**b**) Number of inter-plane ISL sun outages of different duration.  
Figure 6: Satellite number of the failed ISL within an hour.  
additional routing overhead is required, and the routing table for each cycle is generated by the Dijkstra shortest-path (DSP) algorithm. Our algorithm needs to collect link information in a limited area and traffic information from links that are about to fail at \(t_{s}\) time before sun outage occurs, and centrally calculate paths for all different pair of satellite source and destination nodes so that the traffic can be redistributed before failure. After the occurrence of sun outage, these services will be routed and forwarded according to the pre-calculated path, and the priority of forwarding according to the path is higher than that of forwarding according to the routing table.
# Investigation of the Influence of Splitter Blades on the Resonance Conditions of Impellers
###### Abstract  
The conventional resonance conditions are derived based on the conventionally designed impellers without splitter blades. This paper proposes the resonance conditions for impellers under the excitation from the impeller-diffuser interaction with attention paid on the influence of splitter blades. A lumped parameter model is established and the modal analysis is carried out. The blade-based representative modal vector (RMV) is defined. The influence of splitter blades on the impeller's traits of modes is investigated by analyzing the spatial harmonic contents of the RMV. Then, given the specific form of the diffuser-induced engine order excitation acting on the main and splitter blades, the resonance conditions are derived. Tuned and mistuned cases are provided for a practical impeller. The resonance conditions are verified by harmonic response calculations. The applications of the proposed resonance conditions in resonance identification and hazard evaluation of different excitations are given. The differences between the proposed resonance conditions and the conventional ones are discussed. The research indicates that even the RMV of the tuned impeller contains two harmonic components due to the existence of splitter blades. When the excitation frequency equals the natural frequency of the impeller and the excitation order matches with either harmonic index of the two harmonics, the resonance occurs. The results of case studies show that the harmfulness of various engine orders of excitation can be exactly evaluated by the joint use of the spatial harmonic contents analysis result and the proposed resonance conditions; however, analyzing based on the conventional resonance conditions may lead to the misjudgment of the harmfulness of the excitations.  
impeller with splitter blades; resonance conditions; impeller-diffuser interaction; lumped parameter model; representative modal vector; mistuning; engine order of excitation +
Footnote †: journal: Applied Physics Letters
## 3 Results
### Case Study in Slovakia  
When selecting the railway line section, we considered the planned development of ETCS in the conditions of ZSR but also in the countries of the European Union. For this reason, the Sturovo-Bratislava railway line was chosen. This track is part of the IV. Pan-European corridor and its importance will grow in international passenger and freight transport.  
The line passes through the southern Slovakia, and it connects the capital of Slovakia, Bratislava, with the state border of Hungary. The entire line is double-track and electrified by a 25 kV 50 Hz AC traction system. The track measures 149 km from the state border in Sturovo to Bratislava. In the Bratislava-Nove Zamky section, a non-public GSM-R network is applied, which serves for the organization and management of railway transport. Currently, the network is only used for voice communication between the train driver and the train dispatcher.  
The line section selected for the assessment of individual variants of the ETCS application was the line section from Sladkovicovo to Senec. This section was chosen because of several aspects. The first is the fact that the highest line speed between the Sladkovicovo-Senec stations is up to 140 km/h. The second factor is that it is the longest interstation section on the ZSR network, with a length of 16 km. The selected section shown in Figure 4 is also a limiting section for calculating the resulting practical throughput of the line.
## 3 Results and Discussion
### In Silico Design of a Protein against Metabolic Syndrome  
Five of the selected proteins were then analyzed by the SGD with the PeptideCutter too, I as described in the Materials and Methods section. Despite the fact that each protein has multiple hydrolysis sites for the enzymes employed, only four of the selected peptides were released: one from rice glutenin, one from chickpea glutelin A-2, and two from rice glutelin B-2. In all cases, the released peptide was the ACEI peptide VY. To facilitate the release of the peptides of interest, we leveraged the specificities of digestive enzymes and designed linker sites substituting amino acids with Phe, which is hydrolyzed at the C-terminus, or Leu, which is hydrolyzed at both the C-terminus and the N-terminus (Figure 1). These substitutions affected residues adjacent to the peptides of interest. Arg and Lys were used as linkers in the N-terminus to substitute hydrophilic or charged amino acids. Chickpea legumin has two DEDEDE hexapeptides in positions 251-256 and 267-272. Here, the proposed modifications were the addition of Leu between each DE repeat. As expected, each of the peptides were released subsequent to SGD after the proposed modifications (Table 3). The rice glutelin residues 244-246 are DEY, and the dipeptides DE and EY are both present in this sequence. We designed a site to release the DE dipeptide because of the high number of ACEI peptides found in this protein. [PERSON] [35] reported that glutelin type A-1 releases multiple ACEI peptides after pepsin digestion; this protein has 95% identity with glutelin type A-2 analyzed here. For none of the other proteins investigated, biological activity predictions derived from bioactive peptides have been published. To the best of our knowledge, this is the first work that proposes modification of proteins to release bioactive peptides after oral ingestion. This can enhance and/or provide specific biological activity to proteins in addition to their nutritional value. Toxicity analyses did not show sequences or motifs indicating toxicity after the proposed substitutions. This work reports a new approach for the use of bioactive peptides as an alternative treatment for metabolic syndrome. Further experimental confirmation is required, because proteolytic enzymes do not always behave as expected. This type of analysis speeds up the design of therapeutic proteins or released peptides. To the best of our knowledge, there are no reported cases of proteins designed with the ability to treat or prevent metabolic syndrome.
The measurement accuracy is improved through some improvement methods and can reach 390 pm/\(\sqrt{\mathrm{Hz}}\) in the 1 mHz to 1 Hz frequency band. By analogy, the OPD caused by the steering mirror can reach 5 pm/\(\sqrt{\mathrm{Hz}}\) in the 1 mHz to 1 Hz frequency band. Firstly, we analyzed the geometric noise generated by the laser incident on the optical mirror. Then, we introduced the design of the interferometer. The interferometer has a strictly equal-arm-length design, which suppresses part of the laser frequency noise. The optical components are fixed by UV bonding to reduce the impact of thermal noise. We also evaluated the performance of the interferometer under vacuum, vibration isolation, and temperature control conditions. It was found that the interferometer cannot meet the requirements of 8 pm/\(\sqrt{\mathrm{Hz}}\) in the 1 mHz-1 Hz range, so it cannot be used directly to measure the OPD of a steering mirror driven by a minor variation in voltage. Finally, the OPD caused by the steering mirror was obtained indirectly by analogy. The OPD can reach 5 pm/\(\sqrt{\mathrm{Hz}}\) in the 1 mHz-1 Hz range, which meets the specified requirement. The TTL noise model is verified by the tests conducted.
# Sino-InSpace: A Digital Simulation Platform for Virtual Space Environments
## 4 Design of Platform Application Modes and Case Study
### Application Directly
#### 4.1.3 Virtual Reality Setup  
Virtual and augmented reality have received a considerable amount of attention by researchers in the last decade and provide new ways to perceive the world [67; 68; 69]. Virtual reality is defined as a computer-generated scenario that simulates experience through senses and perception [70], while augmented reality creates an environment where digital information is inserted in a predominantly real-world view [71]. The well-known basic components of a VR immersive application include input devices (responsible for interaction), output devices (for the feeling of immersion), and software (for a proper control and synchronization of the whole environment). For the better simulation and presence for VSEs, a simple VR setup was constructed in our Space Situational Awareness (SSA) shared laboratory based on Sino-InSpace. The standard mouse and keyboard allow users a relatively easy and normal way of manipulation of a virtual scenario. In addition, Sino-InSpace supports a variety of stereoscopic observations (e.g., red and green, split screen, and blinking) to produce an immersive environment. The first two types have no special requirement for the hardware, and the virtual experience is poor accordingly. The blinking mode is most frequently used with the help of Nvidia 3D vision technology (Figure 14). The output devices consist of a stereoscopic graphic card (Quadro K2000), synchronous signal transmitters, 3D glasses, Panasonic projectors, and a projection screen. The equipment supports up to tens of people viewing stereo content simultaneously, which could better assist in collaborative and multiperspective space science research and education.
# Numerical Design and Laboratory Testing of Encapsulated PCM Panels for PCM-Air Heat Exchangers
###### Abstract  
Heat transfer between encapsulated PCM panels and air plays an important role in PCM-Air heat exchangers. A new design for the encapsulation panel was developed considering practical aspects such as the cost of production and ease of manufacturing, in addition to heat transfer and pressure drop. A number of encapsulated panel surfaces were first investigated via 3D CFD simulations and compared with an existing panel in use by a commercial PCM-Air heat exchanger manufacturer. After validation, 2D CFD simulations were carried out for 32 different geometries to select the most effective design, which was fabricated and tested in the laboratory. Laboratory parameters tested included heat transfer, pressure drop and melting/solidifying. The laboratory results confirmed the improvements of the new panel in comparison with the existing panel and a flat panel. It was found that the proposed design doubled the heat transfer, holds 13.7% more material and the fan can overcome the increased pressure drop.  
PCM-Air heat exchanger; PCM encapsulation; phase change material; active LTES; enhanced heat transfer +
Footnote †: journal: Applied sciences
# A Review on Rainfall Measurement Based on Commercial Microwave Links in Wireless Cellular Networks
## 5 Machine Learning for CML-Based Rainfall Measurement
### Potential of Deep Learning
#### 5.2.2 Gru  
GRU is proposed in [91] and its structure is simpler as compared to LSTM. It eliminates memory cell state and integrates the forgetting and input gates into one update gate to simplify the structural model. Figure 5 shows the structure of the GRU, and Equations (16)-(19) give the basic mathematical computational steps of the algorithm [92]. First, two gate states named reset gate \(r_{t}\) and update gate \(z_{t}\) are obtained from the previous state \(h_{t-1}\) and the current input \(x_{t}\). Second, \(h_{t-1}\) x \(r_{t}\) is spliced with input \(x_{t}\), and then through a tanh  
Figure 4: LSTM cell structure.  
activation function to covert the data into the range of \(-1\)\(\sim\)1; that is, \(\widetilde{h_{t}}\) is obtained. Finally, the current hidden state \(h_{t}\) is obtained through the update gate \(z_{t}\).  
\[z_{t}=\sigma(W_{z}\cdot[h_{t-1},x_{t}]), \tag{16}\]  
\[r_{t}=\sigma(W_{r}\cdot[h_{t-1},x_{t}]), \tag{17}\]  
\[\widetilde{h_{t}}=tanh(W\cdot[r_{t}\times h_{t-1},x_{t}]), \tag{18}\]  
\[h_{t}=(1-z_{t})\times h_{t-1}+z_{t}\times\widetilde{h_{t}}. \tag{19}\]  
where \(W_{z}\), \(W_{r}\), and \(W\) are weight matrices. In the GRU model, the reset gate defines how to combine new input with previous memories, and how much memory should be retained is decided by the update gate. Some variants of GRU have been proposed and evaluated by reducing parameters in the update and reset gates [93]. Considering the hardware computing power and time cost, the more practical GRU is suggested to be chosen. However, if training data are sufficient, LSTM may generate better predictions due to its strong expressive ability. So, which model to use depends on the system requirement. The GRU model has been used in CML-based rainfall measurement (e.g., [65]), which we have discussed in Section 4.4.
# FANET Routing Protocol Analysis for Multi-UAV-Based Reconnaissance Mobility Models
## 6 Discussion
### Remaining Issues
Therefore, the physical characteristics of a UAV should be designed for specific reconnaissance scenarios to achieve optimal performance and mission success. However, we only consider the communication distance and speed of the UAVs, which is implementable in our network simulator. We leave the considerations on the physical characteristics of the UAVs as future work. In this paper, we did not include these issues as our experimental conditions. However, we could consider these issues in future research for a reconnaissance scenario closer to a more realistic environment and for adoption of more advanced technologies.
## 3 Results and Discussion
### Gold Adsorption from Cyanide Media
#### 3.2.2 Effect of Aqueous pH Value  
Figure 1 shows the results obtained for the adsorption of Au(CN)\({}_{2}\)\({}^{-}\) at various aqueous pH values. The carbon nanotubes dosage used in the experiments was of 2 g L\({}^{-1}\). The aqueous phase contained 0.01 g L\({}^{-1}\) of gold(I) at various pH values. The results shown in Figure 1 demonstrate that the variation of the aqueous pH value increases the removal of gold when these pH values are shifted towards more acidic values. It should be noted here that the gold(I)-cyanide complex is stable even at acidic pH values and only decomposes at these low pH values after a long time (several hours) to yield a yellow AuCN solid. The experimental values obtained at pH 13 were used to estimate the rate law in the adsorption of gold(I) by these multiwalled carbon nanotubes, experimental data best fitted to the film-diffusion controlled mechanism (r\({}^{2}\): 0.9542):  
\[\text{ln}(1-\text{F})=-\text{kt} \tag{2}\]  
where F is the factorial approach to the equilibrium, defined as:  
\[\text{F}=\frac{\left[\text{Au}\right]_{\text{nt,t}}}{\left[\text{Au}\right]_{ \text{nt,e}}} \tag{3}\]  
where [Au]\({}_{\text{nt,t}}\) and [Au]\({}_{\text{nt,e}}\) are the gold concentration in the nanotubes at an elapsed time t and at equilibrium, respectively, and k is the rate constant (0.59 min\({}^{-1}\)).  
\begin{table}
\begin{tabular}{l l l l l l} \hline \hline  & **D** & **G** & **D\({}^{\prime}\)** & **2D** & **G+D** \\ \hline Raman shift & 1339 & 1573 & 1607 & 2675 & 2913 \\ Area signal & 102.4 & 76.2 & 6.8 & 90.1 & 106.8 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Raman data of the multiwalled carbon nanotubes.