esa-sceva/satcom-chunk-collection huggingface dataset:
## 4 Conclusions  
In this paper, the creep properties of CGI at the temperature of 450-550 \({}^{\circ}\)C and the stress level of 100-300 MPa were studied. Using the DMTS creep model, combined with a multiobjective optimization method, the minimum creep rate of CGI was predicted. The main conclusions are as follows:  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Deformation Mechanism** & \multicolumn{3}{c}{**Parameters**} \\ \hline \multirow{2}{*}{GBS} & \(A_{0}\) & \(Q_{A}\) & \(p\) \\  & 1.8183 \(\times\) 10\({}^{-15}\) & 3.8522 \(\times\) 10\({}^{5}\) & 13.48 \\ \hline \multirow{2}{*}{IDG} & \(B_{0}\) & \(Q_{B}\) & \(n\) \\  & 5.3853 \(\times\) 10\({}^{-33}\) & 5.0818 \(\times\) 10\({}^{5}\) & 27.47 \\ \hline \multirow{2}{*}{IDC} & \(C_{0}\) & \(Q_{C}\) & \(m\) \\  & 7.2431 \(\times\) 10\({}^{-4}\) & 2.1537 \(\times\) 10\({}^{5}\) & 6.40 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Parameter values of creep model of CGI under different mechanisms.  
Figure 7: Comparison of predicted and experimental values for the minimum creep rate of CGI. (**a**) Comparison of predicted curves with experimental values, and (**b**) comparison of predicted and experimental values at twice the error.  
At the temperature of 450-550 \({}^{\circ}\)C and the stress level of 100-300 MPa, the creep characteristics of CGI were related to the three factors of test stress, creep time, and test temperature. Compared with stress, the temperature had a greater impact on the creep damage of CGI. Therefore, priority can be given to improving the cooling performance of the engine cylinder head to reduce the temperature load to improve the reliability of the cylinder head and the engine;  
According to the DMTS model, the creep deformation of CGI was mainly caused by three mechanisms: GBS, IDG, and IDC. At different stress and temperature ranges in this study, creep was dominated by different mechanisms. As a result, according to the application range of CGI, its microstructure can be adjusted reasonably to suppress the dominant creep deformation mechanism in this range, thereby prolonging the service life of CGI;  
Under a wide range of temperature and stress, the DMTS creep model can reasonably express the minimum creep rate of CGI. Moreover, it has been proved that the multi-objective optimization method can solve the problem where the parameters cannot be fitted by the conventional linear regression method because of the small number of data points, so the method has good engineering practicability.  
Conceptualization, G.J.; methodology, G.J.; validation, J.W.; data curation, J.Z. and S.S.; writing--original draft preparation, S.L.; writing--review and editing, G.J. and G.C. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Key Laboratory of Science and Technology for National Defense, grant number 61422120301.  
Not applicable.  
The datasets supporting the conclusions of this article are included within the article.  
The authors declare no conflict of interest.
# DNS-IdM: A Blockchain Identity Management System to Secure Personal Data Sharing in a Network
## 3 Identity Management Challenges  
In this section, we focus on three identity management systems that are imposed on the blockchain network. Table 1 presents a comparison of the three identity management systems. The state of current identity systems is problematic, as mentioned in the uPort paper [38]. Moreover, digital identity systems that are widely deployed are fragmented, mostly deliver poor user experience with the repetitive logins, and are soiled by multiple service providers [38]. The centralization architecture also results in valuable data being compromised by attackers [39].  
There are several designs of identity management systems deployed on the blockchain trying to accomplish self-sovereign identities such as Cambridge Namecoin [40], Blockverify [41], and Cambridge Blockchain [42]. However, this section analyses the most advanced identity management systems, uPort, Sovrin, and ShoCard, and also reveals the current challenges these models are facing.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**IdM Systems**} & \multicolumn{3}{c}{**Control**} & \multicolumn{3}{c}{**Security**} & \multicolumn{3}{c}{**Privacy**} \\ \cline{2-10}  & \begin{tabular}{c} **Policy** \\ **Mangement** \\ \end{tabular} & \begin{tabular}{c} **Explicit** \\ **Consent** \\ \end{tabular} & \begin{tabular}{c} **Basic** \\ **Security** \\ \end{tabular} & \begin{tabular}{c} **Multi-Lateral** \\ **Security** \\ \end{tabular} & \begin{tabular}{c} **Anonymity** \\ **Support** \\ \end{tabular} & \begin{tabular}{c} **User** \\ **Empowering** \\ \end{tabular} & \begin{tabular}{c} **Data** \\ **Minimization** \\ \end{tabular} & \
\begin{tabular}{c} **Remote** \\ **Admin** \\ \end{tabular} &
\begin{tabular}{c} **Privacy** \\ **Standard** \\ \end{tabular} \\ \hline uPort & ✓ & ✓ & ✓ & ✗ & ✓ & ✓ & ✓ & ✓ & ✗ \\ \hline Sovrin & ✗ & ✓ & ✓ & ✓ & ✓ & ✓ & ✗ & ✓ \\ \hline ShoCard & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✗ & ✗ & ✓ \\ \hline \hline \end{tabular}
\end{table}
Table 1: Identity management system’s comparison table. IdM, identity management.
## 3 Results and Discussion of Biosensor Formation and Its Validation
### Saturation of the Biosensor Surface with a Ligand (Receptor)  
Determination of the optimal ligand (receptor) concentration is the first step in the construction of a biosensor. The biosensor was prepared for testing as described under 'Chip preparation'. The antibody concentration values used were 1-25 ng/mL for VEGF-A and 1-60 ng/mL for FGF-2. The optimal concentrations were selected to ensure complete saturation of the biosensor surface; these were 20 ng/mL for VEGF-A and 40 ng/mL for FGF-2. The saturation curves are shown in Figure A2 in the Appendix A.
## 2 Data and Methodology
### Modeling of Power Curve
#### 2.5.1 Power Curve Using PAGVs and Plates  
Power Augmenting Guiding Vanes (PAGVs) and concentration plates can improve the value of \(C_{p,max}\). [PERSON] et al. [33] used plates to eliminate the negative torque in the returning blade, obtaining a \(C_{p}\) of 0.27, and almost duplicating the typical value of 0.15. [PERSON] et al. [34] studied the influence of the inclination angle of the plates obtaining a \(C_{p,max}\) of 0.38, or even 0.48, using omnidirectional vanes. Obviously, the use of these vanes also reduces the cut-in speed up to 1 m/s or even 0.5 m/s.  
Given these values in the literature, three paradigmatic cases and power curves are considered for this study, keeping the generator of 250 W and the cut-off of 25 m/s, and applying an analogous method to the previous section. Table 3 shows the three cases, with the first one being the referential case analyzed before.  
The cases C1, C2, and C3 represent progressive paradigmatic cases with the case C2 as the intermediate and reasonable one. Hence, C1 represents the worst case without any kind of improvements by vanes and plates, and C3 represents the best case applying complex aerodynamic design.  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Case** & \(C_{p,max}\) & **Cut-in (m/s)** & \(U_{rated}\) **(m/s)** & \(U^{3}\) **Zone Equation** \\ \hline C1 & 0.15 & 2 & 14.0 & \(P=0.091U^{3}-0.728\) \\ C2 & 0.30 & 1 & 11.1 & \(P=0.182U^{3}-0.182\) \\ C3 & 0.50 & 0.5 & 9.4 & \(P=0.302U^{3}-0.038\) \\ \hline \hline \end{tabular}
\end{table}
Table 3: Three paradigmatic cases (inferior limit, intermediate, upper limit) according to the improvement of efficiency in terms of \(C_{p,max}\) and cut-in speed.  
Figure 9: Estimated power curve of the Savonious drag-type turbine for a 250 W generator without guiding vanes or plates.
# An Energy-Efficient Approach to Enhance Virtual Sensors Provisioning in Sensor Clouds Environments
## 4 The Proposed Approach
### ACOSIMv2--Ant Colony Optimization for Sensor Selection Based on Similarity
#### 4.2.3. Pheromone Update Procedure  
The ACO construction procedure leads ants to build their solutions by selecting vertices from the graph \(G\). The ants select at least one physical sensor from all of the clusters formed. The success of the solution construction procedure relies on the design of pheromone deposition and heuristic information. The pheromone is deposited between every pair of physical sensors to record the historical desirability of assigning them to the solution to be constructed. In the provisioning problem, the Equation (6) represents this desirability, since we expect to minimise the equation as maximum as possible. This way, the pheromone deposited between an unassigned physical sensor (\(f\)) and an physical sensor node already in the solution (\(e\)) can be expressed as:  
\[\tau_{e,f}(t+n)=\rho\cdot\tau_{e,f}(t)+\Delta\tau_{e,f} \tag{10}\]  
\[\Delta\tau_{e,f}=\sum_{a=1}^{N_{A}}\Delta\tau_{e,f}^{a} \tag{11}\]  
\[\Delta\tau_{e,f}^{a}=\left\{\begin{array}{cc}Q/L_{a}&\text{if}&a_{th}\text{ ant used the edge}(e,f)\\ 0&\text{otherwise}\end{array}\right. \tag{12}\]  
where:  
* \(e\) is a sensor node already in the solution;
* \(f\) is an unassigned sensor node;
* \(\tau_{e,f}(t)\) is the intensity of pheromone on the link (\(e,f\)) in time \(t\);
* \(\Delta\tau_{e,f}^{k}\) is the amount of pheromone deposited on the edge (\(e,f\)) by the \(a_{th}\) ant within the time interval (\(t,t+n\));
* \(Q\) is a constant;
* \(L_{a}\) is value of equation 6 considering the sensor nodes selected by the \(a_{th}\) ant; and
* \(\rho\) is a constant smaller than 1; otherwise the pheromone would accumulate without bound (0.5 is recommended).
## 5 Role of Local Sequence Organization  
In a study combining electron cryo-tomography with biochemical analyses of DNA minicircles, it was demonstrated that depending on the supercoiling level the DNA can adopt a range of distinct conformations [71]. However, the response to superhelical stress also depends on the DNA sequence organization [53]. In particular, local DNA sequence organization was shown to be determinative for transition dynamics between alternative 3D structures demonstrating coordinated, long-range interactions within a common topological domain [72; 73; 74; 75]. These long-range interactions vary as a function of superhelical density and likely arise from the competition of discrete transitions for the free energy of negative supercoiling [72]. Thus, although the variation of superhelical density alone can determine the distinct 3D conformations of DNA [71], the available supercoil energy can also specify various DNA structures depending on the local sequence organization [53; 76].  
On a local scale, the DNA sequence organization of individual gene/operon promoter regions demonstrates different helical periodicities associated with particular responses to supercoiling, as well as enrichment for sequences stabilizing alternative DNA structures and intrinsically curved DNA [77; 78; 79; 80]. Intrinsically curved DNA sequences were shown to facilitate the pinning of plectonemic supercoils upstream of the promoter [81]. Furthermore, the variations in canonical promoter elements such as the G/C content of the discriminator sequence (the sequence between the \(-10\) hexamer and the transcription start site) and the length of the spacer between the \(-10\) and \(-35\) hexamers, were shown to be determinative for the promoter supercoiling response [82; 83; 84; 40; 42; 85; 86]. For example, the \"stringent\" promoters (such as stable RNA promoters) that are, respectively, down- and up-regulatedby ppGpp and negative supercoiling are characterized by G/C-rich discriminators, short (16 bp) spacers, and suboptimal \(-\)35 hexamers as well as anisotropically bendable upstream activating sequences (UAS) forming coherently bent DNA microloops associated with RNAP [55; 87; 88]. Overall, the more A/T-rich and more G/C-rich sequences are associated with a response to low and high levels of negative superhelicity, respectively [42; 84; 85].
# Assessing Blockchain Consensus and Security Mechanisms against the 51% Attack
## 4 Consensus Mechanism Weaknesses
### Proof of Stake (PoS)  
Proof of stake (PoS) is a consensus mechanism which authorizes blocks based on the stakes a participant pours into the network. Miners in possession of a large number of coins possess more power than other participants [32]. Peercoin was the first cryptocurrency to use this consensus in 2012. A randomized process is followed to consider the creator of the next block. The process involves obtaining the detail about the total amount of the cryptocurrency, and also the duration for which it has been maintained. The advantage of PoS consensus is that it does not require participants to go through an expensive mining process such as PoW.  
PoS is vulnerable due to its centralized attributes [33]. While staking a large portion of wealth consistently, a participant becomes a powerful entity within the network and also able to influence the well-being of the network. By achieving the majority of the supply, a malicious stakeholder can take advantage of the nothing-at-stake problem. PoS suffers from weak subjectivity, and the implementation process is also very complex and challenging [34]. To conduct a 51% attack, an adversary is required to achieve the 51% of the distinct cryptocurrency. However, the cost of achieving 51% of the total stake can be immense. Therefore, the threat level of the 51% attack can be low compared to PoW. Our study reveals that PoS can be exploited by the long-range attack [13]. The P + epsilon attack cannot be executed since an attacker needs to achieve a large budget to contribute as a security deposit for the participants while voting for the minority [29]. PoS can be exploited by a Sybil attack, and a DDoS attack can also disrupt part of the network.
###### Abstract  
The radio-over-fiber (RoF) technique has gained a lot of interest recently, as the millimeter-wave signals can be generated and delivered in the optical domain with the advantages of low attenuation, high capacity, and being free from electromagnetic noise interference (EMI). In this paper, we propose and experimentally prove a self-start multi-wavelength laser source based on a distributed feedback laser diode (DFB-LD) for the RoF transport system. The self-start multi-wavelength laser source generates stable laser power with less than 0.18 dB power fluctuation and exhibits good stability. In order to estimate the transmission performance, data is externally modulated onto the multi-wavelength by a reflective semiconductor optical amplifier (RSOA) and transmitted through single-mode fiber (SMF). The experimental result proves that the proposed RoF transport system achieves error-free transmission and clear eye diagrams.  
radio-over-fiber; multi-wavelength laser; wireless communication system
# Development of a Self-Powered Magnetorheological Damper System for Cable Vibration Control
###### Abstract  
A new self-powered magnetorheological (MR) damper control system was developed to mitigate cable vibration. The power source of the MR damper is directly harvested from vibration energy through a rotary permanent magnet direct current (DC) generator. The generator itself can also serve as an electromagnetic damper. The proposed smart passive system also incorporates a roller chain and sprocket, transforming the linear motion of the cable into the rotational motion of the DC generator. The vibration mitigation performance of the presented self-powered MR damper system was evaluated by model tests with a 21.6 m long cable. A series of free vibration tests of the cable with a passively operated MR damper with constant voltage, an electromagnetic damper alone, and a self-powered MR damper system were performed. Finally, the vibration control mechanisms of the self-powered MR damper system were investigated. The experimental results indicate that the supplemental modal damping ratios of the cable in the first four modes can be significantly enhanced by the self-powered MR damper system, demonstrating the feasibility and effectiveness of the new smart passive system. The results also show that both the self-powered MR damper and the generator are quite similar to a combination of a traditional linear viscous damper and a negative stiffness device, and the negative stiffness can enhance the mitigation efficiency against cable vibration.  
cable vibration mitigation; MR damper; vibration energy harvesting; rotary DC generator; modal damping ratio; negative stiffness Article
# Secure Image Transmission Using Multilevel Chaotic Encryption and Video Steganography
## 3 Methods and Materials
### Mathematical Preliminaries
#### 3.2.4 Gingerbread Man Map  
The gingerbread man map is a two-dimensional chaotic map used in encryption systems to introduce randomness and enhance security. It displays chaotic behavior in some regions while maintaining stability in others, forming a characteristic \"gingerbread man\" shape [26].  
\[z_{(v+1)}=1-L(v)+|z(v)|\]  
\[L(v+1)=z(v)\]  
\(Z(v)\), \(L(v)\) are the current coordinates of the point.  
Where \(Z(v)=0.3577\), and \(L(v)=0.13245\). This map has the following features:  
A mix of chaotic and stable regions, with distinct domains forming a recognizable pattern (head, arms, legs, and belly);  
Points within stable regions follow predictable orbits, and points outside exhibit chaotic paths;  
Applicability for generating pseudo-random sequences in image encryption [26].
## 4 Torque and Line Voltage of Three-Phase FRM  
During the rotation of the rotor of the single-phase FRM shown in Figure 1b, all electromagnetic processes are repeated after the rotor is rotated by 90 mechanical degrees. Therefore, 360 electric degrees corresponds to 90 mechanical degrees, i.e., one electrical revolution.  
The three-phase FRM (Figure 3) consists of three single-phase machines rotated relative to each other by a third of the electrical period or by 30 mechanical degrees. After performing calculations for one single-phase machine, phase voltage and torque of two other single-phase machines can be obtained by shifting the waveform by a third of a period (120 electrical degrees). This shifting of the waveforms is particularly easy to be carried out when the number (\(n\)) of uniformly spread points on a period is a multiple of 3, i.e., \(n=3k\), where \(k\) is integer. In this case, the voltage and the torque of the other two machines are determined by making a phase shift for \(k\) and \(-k\), respectively.  
In the case of a Y-connection, the line voltage of the machine is determined by subtracting two phase voltage values. Owing to the fact that shifts do not alter the triplen harmonics, such harmonics are not present in the linear voltage. However, in particular, even harmonics can be present. Therefore,  
Figure 4: Calculation area scheme.  
the positive and negative half-periods of the line voltage waveform may not coincide entirely. In particular, maximum voltage value and minimum voltage value may not match. This will be seen later.  
The three-phase machine torque is determined as the sum of the torques of the three single-phase machines. Therefore, the period of the torque waveform equals to one third of the electric period or, in other words, only triplen harmonics are existing in the torque waveform.  
Although the calculation of the torque waveform of the three-phase FRM is fully based on the calculation of the torque waveform of the single-phase FRM, the former requires more computational efforts than the latter. The torque waveform period of the three-phase FRM is three times as short as that of the single-phase FRM and is represented with three times less the points. In this study, to obtain 15 points per period of the three-phase FRM, 45 points per period of the single-phase FRM are taken. Therefore, 46 boundary problems are solved: 44 boundary problems inside the electric period and two boundary problems at its ends.
## 1 Introduction
In other words, in the mining process with tools such as conical picks or cutting disks, we can obtain similar reaction forces for rocks that differ significantly in strength parameters determined in static tests (UCS). Therefore, from the point of view of modeling rock mining or crushing processes, what is important is not only information about the development of dynamic stresses as a function of strain rates, but also the influence of all types of material discontinuities, such as porosity, on the above. There are studies in the literature on the influence of porosity on the strength parameters of rocks in the static range [6; 25]. However, the area of dynamic research assuming high strain rates and the influence of porosity is not that well understood. Dynamic tests are often carried out on rock samples, but researchers do not identify the porosity parameter of rock samples. Valuable data in this regard are provided by the results of the above-mentioned rock tests regarding water saturation [15]. The influence of water saturation and porosity of coal (soft coal) under dynamic loads is presented in [18; 26], which studied the effect of water saturation in two types of sandstones with different strength and porosity parameters under dynamic loading conditions. Research on the influence of water saturation in high-porosity coral rocks on the value of dynamic stresses was presented in the publication [12]. The basic research problem in this area is to conduct comparative tests on rock samples with the same or similar strength parameters, but differing in porosity. However, due to the randomness of the physical and mechanical properties of rocks, this is unlikely. Therefore, each laboratory test in this area provides valuable information relevant to the current state of knowledge. Taking into account the above, the authors conducted dynamic tests of sandstone samples with different strength parameters, which differ significantly in the porosity parameter, so that it was possible to comparatively assess the impact of the above-mentioned parameters on dynamic stresses. Strength parameters were identified in static tests. The porosity of the samples was examined using computed tomography. Dynamic tests were carried out using the split Hopkinson bar method on cylindrical samples with a diameter of 23 mm. Three sample with different ratio of slenderness were used for testing.