esa-sceva/satcom-chunk-collection huggingface dataset:
### Paper Motivations and Contributions  
This paper helped to develop a comprehensive probabilistic framework for PEPS that could reflect changes in the overall dynamic behavior of a system under different uncertainties and disturbances.  
In this respect, the primary motivations and contributions of this work were as follows:  
* A workflow diagram for probabilistic robust stability and performance analysis was proposed; it was helpful to be able to better understand how the probabilistic robustness assessment was implemented and how different calculation parts were related.
* Various features of the probabilistic robustness assessment were clarified; this paper presented how probabilistic assessment could be used for small-signal analysis meth  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Methods** & **Nominal Stability** & **Robust Stability** & **Mathematical Complexity** & **Computational Burden** & **Conservatism** & **Link to Other Power System Studies** \\ \hline Conventional nominal & & & & & & \\ stability analysis, e.g., & & & & & & \\ eigenvalues analysis, Nyquist method, etc., [8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18] & Yes & No & Low & Low & Hard \\ \hline Analytical robust & & & & & & & \\ stability-analysis methods, e.g., \(\mu\)-analysis [19; 20; 21; 22; 23; 24; 25] & Yes & Yes & High & Medium & High & Hard \\ \hline Probabilistic robust stability analysis [31; 32; 33; 34] & Yes & Yes & Medium & High & Low & Easy \\ \hline \hline \end{tabular}
\end{table}
Table 1: State-of-the-art nominal and robust stability-analysis methods.  
ods of PEPS, how obtained results could be interpreted, and what their advantages and disadvantages were.
* Nominal and robust stability and performance definitions and indices were provided; this paper tried to clarify nominal stability and performance, robust stability, and performance and how they could be calculated based on the critical mode and damping factor and ratio.
* A link between system stability and the risk and reliability assessment was provided and the probabilistic assessment methods could provide PDFs and CDFs of stability indices; therefore, they could provide the probability of a specific condition or a system's stability and instability. This information could be used for a further power system reliability assessment.
* Major contributing parameters to system stability and performance (parameters or control loops with a more significant impact on the maximum damping factor and minimum damping ratio) were found.
## 2 Scenario Description and Schematic  
Using intelligent urban transportation systems as well as vehicle-to-vehicle and vehicle-to-infrastructure technologies, the CAEFVs located in the upstream area of signalised intersections can receive important state information in advance, including their positions, traffic signal phase status, and surrounding vehicle information. Moreover, the wireless charging scenario at signalised intersections (WCSSI) consists of multiple scenario elements including vehicles, static environments, and dynamic environments. To hierarchically analyse a combination of vehicles, roads, and environmental elements in a coupled scenario, an adapted hierarchical model was used for a scenario representation based on the study conducted by [PERSON] et al. [45]. In this model, scenarios are divided into basic components, and only the interactions between all five layers represent a complete scene. The five-layer model is used to construct the scene depicted in Figure 1a with the three lower layers describing its static parts. The fourth layer focuses on moving objects, while the fifth layer describes the environmental conditions and vehicle-to-everything communication.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Authors**} & **Electric** & **Signalised** & **Passing** & **Wireless** & **Mixed** \\  & **Vehicles** & **Intersections** & **Strategies** & **Charging** & **Traffic** \\ \hline [PERSON] et al. [40] & X & & & & X \\ [PERSON] et al. [41] & X & & & X & X \\ [PERSON] et al. [42] & & X & & X & X \\ [PERSON] et al. [43] & X & & & X & X \\ [PERSON] et al. [44] & X & & & X & \\ This study & & & & X & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Overview of eco-driving related works.  
Figure 1: Wireless charging scenario at a signalised intersection [45].  
Figure 1b shows that the WCL at the signalised intersection includes a control area (CA) with a start point \(o\) and termination point \(s\), containing the upstream and downstream regions of the signalised intersection. The wireless charging area (WCA) with length \(D_{2}\) starts at point \(s_{1}\) and ends at point \(s_{2}\), and the stop line of the signal crossing is positioned at \(s_{3}\). When CAEFVs pass through a conventional signal crossing, the red signal status causes the vehicles to remain idle and wait before the stop line, resulting in the waste of the user time and vehicle energy. When CAEFVs pass through a signal crossing paved with the wireless charging facilities, they travel at a lower speed in the WCA while avoiding the energy waste caused by the vehicle stopping at the signal crossings and improving the vehicle's remaining power status, turning the time-wasting drawback into a power-gain advantage. Therefore, based on the results of a hierarchical analysis of the described scenario, the initial vehicle speed, wireless charging efficiency, and WCL length are considered the key parameters of CAEFVs passing through the signalised intersections in this study to verify the effectiveness of the optimal driving model in different strategies.
## 5 Results
### Tested Modulations  
We have tested several modulation techniques for low-power simplex remote sensors communications in the HF band over the last decade. The system is currently transmitting the data from the sensors of the Ebre Observatory in the ASJI, but it also could be used to transmit the data from any other remote sensor.  
Figure 10: Correlation of MUF(3000)F2 with FLA and MUF Rec 533 **(left)** and with SNR **(right)** during the 2009–2010 campaign. See text for more details.  
When designing a communication system, there is always a trade-off between robustness and bit-rate. If robustness and Bit Error Rate (BER) are main factor to be optimized, spread spectrum techniques [16] are the choice then. On the other hand, if bitrate and spectral efficiency are the key issue, then OFDM and Single Carrier [16] have to be tested.  
A synthesis of the BER and bitrate results are shown, but more detailed results for the entire modulation tests can be found in the following works: (i) comparison between DS-SS and OFDM in [32] (see Table 3); (ii) comparison between DS signaling and quadriphase, in order to increase the bitrate of DS-SS without worsening the BER in [33] (see Table 4); (iii) comparison between several types of Single Carrier in [60] (see Table 5).  
Figure 11: Correlation of the Doppler shift suffered for the radio link between ASJI and Spain (bottom) with the vertical drift velocity of the F region recorded in Spain (top) for February season. Note that SR and SS correspond to sunrise and sunset times at latitudes of the receiving site and at the altitude of the ionospheric F-region (300 km).  
family of Gold PN sequences [61] to address \(n\) data for each sent sequence, where the PN sequence is length \(2^{n}-1\). As shown in Table 4, bitrate is clearly improved by setting a symbol time that performed good results in the comparison of Table 3, and increasing the PN sequence length and reducing the number of samples per chip. Stability and robustness are the fundamental goals of these two DS-SS variations.  
Finally, Table 5 shows the proof of principle of a Single Carrier proposal for the ionospheric channel. The goal of this proposal is to increase the bitrate significantly, reaching one order of magnitude higher than the shown in Table 4. Despite the bitrate improval, the BER results shown are not as good as the ones for signaling and quadriphase.  
Nowadays, the research group is working in the evolution of Single Carrier and also in increasing the bandwidth of signaling and quadriphase transmissions to improve their BER and bitrate results.
# A Proposed Soft Computing Model for Ultimate Strength Estimation of FRP-Confined Concrete Cylinders
## 2 Research Objectives  
Generally, ANNs have been used in applied science and engineering problems, because of their positive features. These features can be summarized as: (I) ability to handle the uncertainties, (II) ability to find the existing sensitivity and, finally, (III) proposing a mathematical relationship between input and output data. This research work addresses the following main objectives. First, the feed-forward backpropagation neural network is used to predict the compressive strength of FRP-confined concrete cylinders from a set of experimental data. For this purpose, a database of experimental data has been established based on various publications. Based on these data, the main effective parameters that have an influence on the compressive strength of FRP-confined concrete cylinders (FRPCCC) are assessed. Finally, using the feed-forward backpropagation neural network, a new formulation is proposed, and the effects of the presented formula are compared with existing models.
## 2 Distributed Optical Fibre Sensors
### Rayleigh-Based Distributed Sensing  
Rayleigh scattering is an elastic process resulting from local variations of refractive index due to heterogeneity and density fluctuation of the material [12,13]. Because of that heterogeneity, a small portion of the incident light is scattered at specific points called scattering centres. These scattering centres are randomly distributed along the fibre and act as weak reflectors, reflecting the light in all directions. However, only the fraction of the scattered light falling within the angle of acceptance of the fibre in the opposite direction is captured by the guiding structure of the fibre itself, and back-propagates to the input.  
The backscattered signal has peculiar properties [14]: first of all, the intensity of incident light backscattered at a scattering centre is attenuated over the round-trip length (i.e., from the fibre input to the centre's position). Furthermore, on average, each portion of fibre illuminated at any time by a single pulse is expected to radiate the same backscattered intensity broadly. This effect can be easily revealed with a broadband pulsed incident light. However, when a narrowband laser is used, each scattering centre illuminated by the same probe pulse contributes coherently to the backscattered light. Overall, the intensity and phase of the light reflected all along the fibre are determined by the vector sum of all electric fields radiated by the scattering centres, and therefore depend on the amplitude and position of scattering centres along the fibre. Both the amplitude and position are randomly distributed but fixed in time as long as the relative phase difference (i.e., optical distance) among illuminated scattering centres does not change [15]. In the case of broadband sources, these coherent effects still present, determining only a tiny fluctuation around the average scattering intensity.  
At the basis of all Rayleigh DOFSs, there is the detection of the counter-propagating signal, and in turn, of the attenuation along the fibre. To this aim, two main approaches can be followed:  
* To determine the attenuation in the time domain, with pulse signals (i.e., to determine the roundtrip impulse response of the fibre), known as optical time domain reflectometer (OTDR).
* To characterise the attenuation in the frequency domain, with a frequency-modulated continuous wave signal (i.e., to determine the roundtrip frequency response of the fibre), known as optical frequency domain reflectometer (OFDR).  
Notably, the intensity of the backscattered signal in single-mode fibres is rather small (approximately 55 dBs lower than that of the probe light), and this represents one of the main challenges to the implementation of Rayleigh-based DOFSs--either in time or frequency domain.
## 3 Results and Discussion
### Fatty Acid Profiles of the Calves' Faces  
The FA profiles of the calves' faeces before the experiment and after 14 days of feeding with fermented MP are given in Table 5. There were significant differences between the CON0 and MP0 groups in most of the faecal FA content (\(p\) < 0.05), with the exceptions of C14:1, C17:1, C18:2, C20:1, and C20:3. The predominant faecal FA were the same in both the CON0 and MP0 groups: C14:0, C16:0, C18:1, C18:2, and C18:3\(\alpha\). After 14 days, C16:0, C18:0, and C18:1 were the predominant faecal FA in the CON14 group, while C16:0, C18:1, C18:2, and C18:3\(\alpha\) were the predominant FA in the MP14 group. After 14 days, there were significant differences between the CON14 and MP14 groups in the percentage of each FA (\(p\) < 0.05), with the exceptions of C4:0 and C16:1. After 14 days, the percentage of C14:0 had decreased in both groups, although the concentration of C14.0 in the MP14 was half that in the CON14 group. The percentage contributions of C16:0, C18:0, and C18:1 increased in both groups, but the relative concentration of these FA was higher in the CON14 group (by 46.2%, 38.1%, and 61.7%, respectively) than in the MP14 group. The relative concentrations of C18:2 and C18:3\(\alpha\) had increased since the start of the experiment by 21.1% and 22.5%, respectively, in the MP14 group but had decreased by 20.9% and 44.3%, respectively, in the CON14 group. The values of C18:2 and C18:3\(\alpha\) were higher (by 35.5% and 2.5-fold) in the MP14 group compared with the CON14 group.  
The total relative concentrations of saturated, monounsaturated, and polyunsaturated FA were similar between the two groups at the beginning of the experiment. However, after 14 days, the total relative contributions of saturated and monounsaturated FA were lower by 30.2% and 15.2% in the MP14 group compared with the CON14 group, whereas the total for polyunsaturated FA were 88.6% higher in the MP14 group than in the CON14 group (Table 5). Finally, additional feeding with MP decreased biohydrogenation of PUFA in faeces. To the best of our knowledge, the impact of fermented MP feed supplement on the FA profile of calves' faeces has not previously been studied. However, similarly to our results, [PERSON] and [PERSON] [53] also found that palmitic (C16:0), stearic (C18:0), oleic (C18:1 n9 cis), and linoleic (C18:2) acids predominated in cattle faeces. Another study reported that C14:0 and C18:2 are important for reduction in rumen methanogenesis, while C18:2 could also lead to a reduction in protozoa [54]. In our study, after 14 days of feeding, the content of C18:2 increased significantly in the MP14 group compared with the CON14 group.
# Dynamic Behavior Analysis and Stability Control of Tethered Satellite Formation Deployment
## 4 Stable Deployment Laws of Tether Release Rate and Tether Tension Control  
Entire TSS configurations require transformation according to different mission requirements. Changing the tether length is the most direct control method of system conception transformation, which includes tether release rate control and tether tension control. During TSS transformation, tether release rate and tether tension control parameters are controlled by a deployment device in the mother satellite.
## 4 Methodology
### Proposed Model
#### 4.1.1 CBAM Module  
The CBAM module incorporates both channel-wise and spatial-wise attention mechanisms to adaptively recalibrate feature maps. The channel-attention mechanism captures inter-channel dependencies, while the spatial-attention mechanism highlights informative spatial regions within each feature map. Mathematically, the channel-attention mechanism is defined as:  
\[\text{Channel Attention}=\sigma(\text{MLP}(\text{avgpool}(x))+\text{MLP}( \text{maxpool}(x))) \tag{3}\]  
\[\text{Spatial Attention}=\sigma(\text{Conv2D}(\text{avgpool}(x))+\text{ Conv2D}(\text{maxpool}(x))) \tag{4}\]  
where \(x\) represents the input feature map, MLP denotes a multi-layer perceptron, and \(\sigma\) denotes the sigmoid activation function. The CBAM module enhances feature discriminability and suppresses irrelevant information, therefore improving segmentation accuracy. As learned from the literature [50], we intentionally refrain from applying dimensionality reduction to preserve a direct relationship between the channels and their corresponding weights.  
For better segmentation accuracy, the CBAM module dynamically recalibrates feature maps to focus on pertinent information using its dual-channel and spatial-attention methods. The module captures inter-channel dependencies and highlights informative spatial regions in each feature map by combining both channel-wise and spatial-wise attention techniques. While the spatial-attention mechanism uses convolutional operations to highlight spatially informative regions, the channel-attention mechanism uses a combination of average pooling and max pooling operations followed by multi-layer perceptrons to capture both global and local channel-wise dependencies. Attention maps are created using the sigmoid activation function to adjust feature responses adaptively, improving feature discriminability and decreasing irrelevant information.
## 2 Design and Fabrication
### Fabrication of Polyimide(PI) Protection Layer  
To protect the micro sensor from the corrosion of the external environment, such as the electrolytic salty seawater, a protective layer composed of a PI (polyimide) film was developed. Polyimide is a kind of organic polymer material with excellent comprehensive properties, such as better high temperature resistance than PDMS, excellent insulation properties, and stability under electrolyte condition. Meanwhile, polyimide can be well attached on the surface of the devices due to its ductility and flexibility. Therefore, a polyimide film was selected as the protective layer for the micro sensor and for protection of the bonding wires.  
After bonding the sensor with packaged PCB by gold wire, polyimide solution of 15% concentration was placed into a vacuum chamber for 30 min to remove the air bubbles. Then, the solution was uniformly dripped onto the top surface of the micro pressure sensor. A high-speed rotary coating machine was used to make the polyimide solution form a uniform thin film. The rotation speed, which is an important factor for the thickness of the polyimide film, was set at 500 rpm for 10 s, then 3000 rpm for 30 s. After spinning, the micro sensor with polyimide film was placed in an oven for further solidification. The heating process for the polyimide film was 80 \({}^{\circ}\)C for 10 min, 120 \({}^{\circ}\)C for 30 min, 150 \({}^{\circ}\)C for 10 min, 180 \({}^{\circ}\)C for 10 min, and then 220 \({}^{\circ}\)C for 40 min. Finally, a thin polyimide film with a thickness of 10 \(\upmu\)m was covered on the top surface of the micro pressure sensor as a protective layer to prevent corrosion by moist air and electrolyte droplets. The device with a 10 \(\upmu\)m-thin PI protection film and the dice itself are shown in Figure 4.  
Figure 3: Fabrication process of the silicon piezoresistive pressure sensor.
# Blockchain-Based Quality Assurance System for Academic Programs
###### Abstract  
Nowadays, technology is increasingly being adopted in different kinds of businesses to process, store, and share sensitive information in digital environments that include enormous numbers of users. However, this has also increased the likelihood of cyberattacks and misuse of information, potentially causing severe damage. One promising technology, which can provide the required security services with an improved level of efficiency, is blockchain. This research explores the use of Ethereum blockchain and smart contracts to create a secure and efficient quality assurance system (QAS) for academic programs. By utilizing blockchain and smart contracts, the proposed approach improves the integrity and reliability of sensitive information processed by the QAS, promotes transparency and governance, and reduces the time and effort required for quality operations. The current approach uses an additional access control layer to further enhance user privacy. Smart contracts automate various quality transactions and saves time and resources, and hence increases the efficiency of the QAS. The interplanetary file system (IPFS) is used to address the challenge of size limitations in blockchain. Additionally, this research investigates the use of various cryptographic schemes to provide robust security services at the application layer. The experimental results showed that the use of a hybrid cryptosystem relying on an Elliptic curve digital signature and AES encryption (AES_ECCSDA) outperforms other counterparts' cryptosystems using an RSA digital signature and AES encryption (AES_RSADSA) and Elliptic Curve Integrated Encryption Scheme (ECIES) in terms of speed. The performance results showed that AES_ECCSDA consumes 188 ms to perform the required cryptographic operations for a standard-quality document with a size of 8088 KB, compared to the 231 ms and 739 ms consumed by the AES_RSADSA and ECIES schemes, respectively. This study presents a prototype implementation of the blockchain-based QAS, which outlines the processing model and system requirements for key QAS processes. It has been found that the cost and time required for blockchain operations vary depending on the size of the input data--a larger data size requires more time and costs more to process. The results of the current study showed that the time delay for blockchain transactions ranges from 15 to 120 s, while the cost ranges from USD 50 to USD 400. This research provides evidence that blockchain and smart contract technologies have the potential to create a secure, efficient, and trustworthy QAS environment for academic programs.  
blockchain; smart contracts; privacy; security; integrity; trustworthiness; quality assurance system +
Footnote †: journal: Applied Sciences
## 3 Results and Discussion
### Case Study 2: Bronze Objects
#### 3.2.2 XRF Analysis  
X-ray fluorescence investigations in the case of finds made of metallic materials allow the qualitative and, under certain conditions, semi-quantitative analysis of the chemical elements in the alloy and elements present on the surface (artificial patinas) induced by ongoing or past corrosion processes. The analysis of both the alloy and the patina can provide useful information in the case of artificial processes for the falsification of typical corrosion patinas, characteristic of archaeological bronzes or more generally of ancient metal finds.  
From the analysis carried out to date, it was possible to verify that the fragments from the two belts are characterized by a very similar chemical composition and the same intensity values of the characteristic peaks of the chemical elements: copper and tin (the major elements), and silicon, iron, nickel, lead, and arsenic (minor or trace elements). The helmet fragment has a high lead content in the matrix of the bronze alloy, which consists mainly of copper and tin. In addition, silicon, titanium, and iron were identified as minor or trace elements. These may have been derived from the ore deposits that were exploited for bronze production [31].  
The XRF spectra for each fragment are shown in Figure 6. They were acquired using the same measurement conditions and reported using the same numerical scale, so they can be directly comparable.  
Figure 5: XRF spectra of Painting 1 **(A,B)** and Painting 2 **(C,D)**. It is important to note that the measurements refer to original areas; however, in the case of Painting 2, it was not possible to avoid thin retouching along the craquelure lines, which resulted in the presence of minimal zinc counts in the XRF spectra.