esa-sceva/satcom-chunk-collection huggingface dataset:
## 6 Conclusions and Future Directions  
In this article, the construction and analysis of alternant codes over Gaussian integers have been introduced with respect to their algebraic background and relevance in dependable digital communication. Using parity-check matrices whose entries are elements of finite commutative local rings with unity, namely, quotient rings of Gaussian integers modulo \(n\), we have created a unified framework to construct error-correcting codes and generalize the classical BCH codes' paradigms. We have shown that these codes share structurally desirable properties with the Gaussian integer ring, including a more intricate algebraic structure and the existence of unit elements, which can help to achieve better error detection and correction. The study of the factorization of \(x^{n}-1\) in these rings formed the basis of encoding and decoding operations. Relatively, it has been indicated through comparative studies that these codes covering Gaussian integers are better than the traditional codes over Galois rings in some noise profiles, particularly in burst error scenarios or low SNR channels. Their suitability to modular arithmetic also implies their suitability to secure and quantum-resistant communication protocols.  
This work can be extended in a number of ways in the future:  
* Minimization of decoding algorithms, especially in the case of long codes, in order to decrease the computational complexity-accuracy trade-off.
* Going to quaternion and even octonion integers to seek structural benefits in other algebraic settings.
* Understanding the performance of these codes in post-quantum communicational systems, as well as blockchain consensus mechanisms and safe distributed systems.  
Finally, alternant codes over Gaussian integers constitute an interesting family of algebraically robust but practically relevant error-correcting codes. Ongoing efforts in this direction could bring about new generations of codes that satisfy the requirements of more complex and security-sensitive communication infrastructures.  
M.S.: conceptualization; methodology; software; formal analysis; investigation; writing--original draft; writing--review & editing; project administration. N.A.A.: conceptualization; validation; writing--review & editing; project administration. All authors have read and agreed to the published version of the manuscript.  
The researchers would like to thank the Deanship of Graduate Studies and Scientific Research at Qassim University for their financial support (QU-APC-2025).  
The original contributions presented in this study are included in the article.  
We are also deeply grateful to our beloved mentor and true gentleman, [PERSON], whose vision and guidance have profoundly inspired our journey as researchers.  
The authors declare no conflicts of interest.
# Scale-Model Experiment on the Delayed Failure Mechanism of Deep Tunnels in Brittle Rock
## 5 Delayed Failure Time Simulation of the Scale-Model Testing
### Numerical Model  
The commercial finite element software Abaqus, version 6.20, was used in the simulation. To increase computational efficiency, a 3D sliced model orthogonal to the tunnel axis was built, instead of using a whole 3D model (Figure 10). The initial stress field was applied to the modelled domain. Boundary conditions were chosen the same as the scale-model testing, the outer boundary was compressed by pressure in Table 1, inner nodes of the tunnel wall were free. Using these boundary conditions, the analytical solutions for stresses around the tunnel were matched well. At the beginning of the simulation the nodes at the tunnel wall were fixed to simulate the undisturbed rock. Drilling of the tunnel was simulated by instantaneous release of this boundary condition.  
To calculate the time-to-failure we employed Equation (5). In Equation (5), [PERSON] proposed that \(\sigma\) is the mean major stress, which is typically the vertical stress in a uniaxial compressive test [26]. [PERSON] proposed the hoop stress \(\sigma_{\theta}\) is the principal stress determining failure at the tunnel wall [25]; thus, here we replaced the \(\sigma\) in Equation (5) with \(\sigma_{\theta}\). The hoop stress is obtained from the Cartesian stress components \(\sigma_{x}\), \(\sigma_{y}\), and the in-plane shear stress \(\tau_{xy}\) as follows:  
\[\sigma_{\theta}=\frac{1}{2}\big{(}\sigma_{x}+\sigma_{y}\big{)}-\frac{1}{2} \big{(}\sigma_{x}-\sigma_{y}\big{)}\cos 2\theta-\tau_{xy}\sin 2\theta \tag{6}\]  
Figure 10: The numerical model.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameters** & \(\mathbf{t_{0}}\)**/**s** & \(\mathbf{b}\) & \(\mathbf{\sigma_{0}}\)**/MPa** \\ \hline Value & \(2.0\times 10^{12}\) & 16.0 & 3.6 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Parameters of delayed failure of the similar material.  
The elastic constitutive model was used in the simulation to obtain the initial hoop stress at the beginning of the excavation. Instantly after the excavation, the status of the surrounding rock would be elastic, then turn into plastic, and finally rockburst. Therefore, the loop stress status can be calculated with the elastic model. The model could be written as follows:  
\[\mathbf{\sigma}=D\mathbf{\epsilon} \tag{7}\]  
where, \(\mathbf{\sigma}\) is stress tensor, \(\mathbf{\epsilon}\) is the strain tensor, \(D\) is the stiffness matrix, which can be written as follows:  
\[D=\frac{E}{(1+\mu)(1-2\mu)}\begin{bmatrix}1-\mu&\mu&\mu\\ \mu&1-\mu&\mu\\ \mu&\mu&1-\mu\\ &&&\frac{1-2\mu}{2}\\ &&&&\frac{1-2\mu}{2}\\ &&&&\frac{1-2\mu}{2}\\ \end{bmatrix} \tag{8}\]  
The parameters of the stiffness matrix were applied to the values in Table 2.
# Fixed Wireless Access in Flexible Environment: Problem Definition and Feasibility Check
## 5 Planned Location Example  
Figure 5 shows a single radio link solution fulfilling stringent latency and throughput requirements through the deployment of a large antenna. The red line indicates the selected solution, meeting all requirements for all served traffic. The shortest (500 m) radio link, while seemingly trivial, would have higher latency due to an extra hop in the optical network (rightmost green line). Therefore, the algorithm did not select it. If availability is not a feasibility constraint, the algorithm can be applied for double radio link deployments.  
The algorithm does not guarantee a cost-optimal solution. For example, depending on antenna and installation costs, a solution utilizing two smaller antenna pairs might be cheaper than one using a single, larger antenna pair. Consider a scenario where FWA must serve diverse service types simultaneously: one with stringent latency but low throughput requirements, and another needing high throughput but tolerating high latency. Figure 6 illustrates a solution using two radio links: low-throughput, low-latency traffic is sent directly to the \(pCT\), while the remaining traffic uses the shortest wireless link.  
Figure 5: Single radio link solution.  
Figure 6: Possible double radio link solution.
## 4 Discussions
### Evolution, Future Trends, and Open Research Areas in Blockchain-Based Data Storage  
Blockchain-based data storage systems have undergone significant evolution since the introduction of Bitcoin in 2008 [21]. Initially, Bitcoin adopted a fully on-chain storage model, where all transactions were recorded directly on the blockchain. However, as scalability limitations, transaction speed constraints, and cost concerns emerged, alternative data storage approaches, off-chain, and hybrid models began to evolve. These developments marked the transformation of blockchain storage technologies, enabling greater flexibility and efficiency. Looking ahead, blockchain-based data storage systems are expected to become more scalable, flexible, and intelligent. The integration of AI-driven access control and security mechanisms has the potential to enhance intrusion detection systems, making them more adaptive and responsive to emerging threats. Furthermore, blockchain's application scope is anticipated to expand beyond healthcare, finance, and IoT into diverse sectors such as supply chain management, agriculture, and education. For instance, blockchain-powered pharmaceutical supply chains can significantly improve data security and transparency in tracking processes. Additionally, regulatory and policy advancements will play a crucial role in shaping the future of blockchain-based data storage. The establishment of international standards will enhance the reliability of these technologies, ensuring compliance with data security regulations and facilitating broader adoption. This will not only bolster blockchain's credibility but also expand its user base by fostering trust among stakeholders. As blockchain storage systems continue to evolve, improvements in scalability, security, and cross-sector adoption will further enhance their potential to revolutionize data storage and management. Future research areas should focus on optimizing on-chain, off-chain, and hybrid storage models, addressing cost efficiency challenges, and integrating emerging technologies such as AI and privacy-preserving cryptographic techniques to solidify blockchain's role as a foundational pillar of next-generation data infrastructure. Table 13 presents the historical progression of on-chain, off-chain, and hybrid storage technologies. \begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Year** & **Data Storage and Processing Model** & **Application Domain** & **Key Applications** & **Underlying Technologies** & **Reference Number** \\ \hline
2008 & On-chain & Finance & Bitcoin (Transaction Storage) & Merkle Trees, Proof-of-Work & [21] \\ \hline
2013, 2014 & On-chain & Finance & Ethereum (Smart Contracts) & Ethereum State Storage, Solidity, and EVM & [74] \\ \hline
2014 & Off-chain & Healthcare & IPFS, MedRec (EHR) & IPFS, Off-chain Hash Storage, Content Addressing & [78] \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Evolution of On-Chain, Off-Chain, and Hybrid Data Storage Methods: Key Technological Advancements, Application Domains, and Underlying Innovations.
## 6 Conclusions  
In this paper, the transmission system and the control system of EASIST were designed according to the working characteristics. The dynamics model of the system was established by power bond graph theory, and the simulation tests were carried out. According to the simulation results, the following conclusions can be drawn:  
1. The dynamic model of the transmission system was established, and the simulation results show that the dynamic model can better describe the dynamic characteristics of the system [46, 47]. This result provides a theoretical basis for subsequent production and processing.
2. A new capture scheme was designed. This scheme reduces the maximum capture time by about 60% while the original functional requirements remain unchanged. In addition, the capture speed is further limited, which can reduce the capture force significantly. This result will enable EASIST to be compatible with small shipborne aircraft.
3. Compared with the fuzzy and PID controller, the designed ANFIS controller has a better speed control effect. The ANFIS controller can achieve a superior speed tracking effect under the maximum loading force during the traction task. This result is of great significance for improving the traction efficiency of EASIST.  
Conceptualization, Z.Z. and Q.L.; methodology, Z.Z. and Q.L.; validation, Q.L. and L.W.; formal analysis, Q.L., D.Z. and T.J.; writing--original draft preparation, Q.L.; funding acquisition, Z.Z. and D.Z. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Hebei Provincial Department of Science and Technology, grant number 20353501D and 21351802D, and Ministry of Science and Technology of China, grant number 2016 YFC0802902.  
Not applicable.  
The authors declare no conflict of interest.
# Synthesis, Structure, and In Vitro Biological Evaluation of Semi-Synthetic Derivatives of Betulin
## 2 Materials and Methods
### Biological Evaluation
#### 2.4.2 MTT Assay  
This technique was applied for the cytotoxicity screening against leukemia cells growing in suspension culture. An assay was performed after 72 h of exposure to varying concentrations of the tested agents. For the last 4 h of incubation, 20 uL of MTT solution was added to each well (MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide; stock solution: 5 mg/mL, Merck, Darmstadt, Germany). The mitochondria of viable cells reduce the pale yellow MTT to a navy-blue formazan: the more viable cells present in the well, the more MTT will be reduced to formazan. At the end of the incubation time, 80 uL of the lysing mixture was added to each well (lysing mixture: 225 mL dimethylformamide (Avantor, Gliwice, Poland), 67.5 g sodium dodecyl sulfate (Merck), and 275 mL of distilled water). After 24 h, when formazan crystals had been dissolved, the optical densities of the samples were read on a Synergy H4 photometer (BioTek Instruments, Winooski, VT, USA) at a 570 nm wavelength. The background optical density was measured in the wells filled with culture medium, without the cells [37].
## 5 Conclusions  
In this manuscript, we introduced a new ELM with its hidden layer defined in the real plane based on the adoption of pilot subcarriers as training set and the inclusion of the regularization parameter in the learning algorithm. The RC-ELM successfully diminishes the distortion caused by the laser phase noises and AWGN in 10 Gbps CO-OFDM networks subject to a negligible computational cost. The obtained results showed that the novel ELM improves the SNR and RF-linewidth requirements below the FEC limit with respect to the feasible PAE and R-ELM for BPSK, QPSK, and 16 QAM subcarrier modulation formats. Furthermore, the RC-ELM almost matched in terms of the BER metric the classic CPE and C-ELM, but these techniques present implementation drawbacks. We also demonstrated that (i) the penalty coefficient allows to increase the ELM effectiveness, and (ii) the system performance obtained from an ELM with complex outputs can be explained by quantifying its training and testing root mean square errors through the EVM metric.  
**Author Contributions:** Conceptualization, D.Z.-B.; methodology, D.Z.-B.; software, D.Z.-B. and M.M.; formal analysis, D.Z.-B.; investigation, D.Z.-B.; writing-original draft preparation, D.Z.-B.; writing-review and editing, D.Z.-B., M.M., C.A.A.-M., A.D.F., P.P.J. and I.S.; project administration, D.Z.-B.; funding acquisition, D.Z.-B. and M.M. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by Vicerrectoria de Investigacion y Posgrado (VRIP) and Faculty of Engineering Science of the Universidad Catolica del Maule.  
**Acknowledgments:** This work was supported by the Laboratory of Technological Research in Pattern Recognition (LITRP), FONDECYT Postdoctorado No. 3190147, CONICYT PFCHA/Beca de Doctorado Nacional/2019 21190489, SENESCYT \"Convocatoria abierta 2014-primera fase, Acta CIBAE-023-2014\".  
**Conflicts of Interest:** The authors declare no conflict of interest.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Technique** & **Training Time** & **Testing Time** & **Total Time** \\ \hline PAE & - & - & \(1.3581\times 10^{-4}\) \\ R-ELM & \(2.0836\times 10^{-4}\) & \(8.4786\times 10^{-5}\) & \(2.9315\times 10^{-4}\) \\ C-ELM & \(6.9722\times 10^{-5}\) & \(2.7325\times 10^{-5}\) & \(9.7047\times 10^{-5}\) \\ RC-ELCM & \(1.5905\times 10^{-4}\) & \(1.1450\times 10^{-4}\) & \(2.7355\times 10^{-4}\) \\ CPE compensation & - & - & \(2.2054\times 10^{-5}\) \\ \hline \hline \end{tabular}
\end{table}
Table 3: Average complexity time in seconds.
# Flow Table Saturation Attack against Dynamic Timeout Mechanisms in SDN
## 7 Related Work
### Saturation Attacks  
Both the control channel and the SDN switches are vulnerable to saturation attacks. Early studies [23; 37] explore the packet-in flooding attack, in which the attackers maliciously generate massive packet-in messages to flood the SDN controller. In this attack, the high packet-in rate is the main feature. AvantGuard [48], FloodGuard [27], and FloodDefender [23] are security mechanisms to mitigate this attack. Based on the probing techniques in SDN, an enhanced attack called table-miss striking attack is presented [36].  
The feasibility of the stealthy flow table saturation attack is explored in recent research. An attacker can leverage the timing-based channel to infer network configuration (e.g., match fields, timeout settings [10], and flow table usage [26]) and launch intelligent attacks. Slow-TCAM [49] is a variant of the saturation attack with slow-rate traffic. [PERSON] et al. [11] study the cache-based behaviors of the flow table and then design attack parameters considering the eviction strategies. Their comparison is presented in Table 1.  
Several countermeasures are proposed to mitigate the malicious flow table overflow. However, many are based on the assumption that the attackers generate high traffic rates [50; 51; 52]. SAIA [30] is a defensive solution against the low-rate table overflow attack. However, it relies on the frequent sampling of flow statistics and can delete benign rules. [PERSON] et al. [10] and SIFT [49] discuss the possibility of using random and dynamic timeouts as defense methods. However, we illustrate that the attacker can adjust the attack pattern in the inferring and maintaining phases to bypass them. In this paper, we study the flow table saturation attack under the circumstance that the controller assigns dynamic timeouts and considers the load-aware adjustment. We discuss the capabilities and behavior of more sophisticated attacks, as well as the attack pattern, in detail, to keep the attack stealthy.
## 2 Methods
### Instrument Scale Recognition Method
#### 2.2.1 Instrument Panel Self-Positioning  
After the identification and extraction of instruments using CA-YOLOv5, it is necessary to further extract the dial for improved scale recognition accuracy. Based on the structural characteristics of arrester pointer instruments, a method that first identifies the outer contour of the dial and then the inner contour is adopted for dial extraction. The process of inner dial contour extraction is illustrated in Figure 4.  
Figure 4: The Process of Inner Dial Contour Extraction. (**a**) Gradient Circle Positioning; (**b**) Contour Extraction; (**c**) I nner Dial Contour Positioning. (Note: The Chinese characters in the image are as follows: Alarm, Model: JQC2-800, Surge Arrester Operation Detector, Date: March 2023, Number: 3831, Shanghai Leichuan Surge Arrester Co., Ltd.).  
Figure 3: Instrument Scale Recognition Method Flowchart.  
Step one involves performing mean blur on the input image to reduce the impact of random noise and quickly obtain the contour lines and the utilization of the Hough Gradient Circle Detection algorithm, as shown in Figure 4a to determine the location of the dial's outer contour. This step aims to reduce background interference and save data on the circle's center coordinates and radius.  
In the second step, as illustrated in Figure 4b, Canny edge detection is applied to the image to filter the extracted contours, removing those that are small and irregular in area. The algorithm includes the following four steps: (1) Apply Gaussian filtering to remove noise from the image. (2) Compute the gradient magnitude and direction of the pixels in the image. (3) With the gradient magnitude and direction of the points known, perform non-maximum suppression to remove all non-edge points. (4) Set upper and lower thresholds to filter processed edges to determine the contour edges.  
The third step conducts an elliptical fitting to the contours that have been filtered. Based on the data retained from step one, a further selection is performed on the fitted ellipse to finalize the inner contour of the dial, as depicted in Figure 4c. The data on the major and minor axes of the ellipse are saved to serve as a basis for calculating the perspective transformation of the dial in subsequent steps.
# A Novel Reconfigurable Vector-Processed Interleaving Algorithm for a DVB-RCS2 Turbo Encoder
## 4 New Approach: Parallel Vector Processing Based Algorithm
### Concatenation  
This phase creates four vectors by concatenating rows of the transposed 2D matrix of the previous phase. The four initial rows are chosen by four pre-calculated offsets determined by the DVB-RCS2 standard parameters \(Q_{0},Q_{1},Q_{2},Q_{3}\), and \(P\):  
* \(\text{offset}_{1}=3\);
* \(\text{offset}_{2}=(3+4Q_{1}+P)\ (\text{mod}\ N)\);
* \(\text{offset}_{3}=(3+4(Q_{0}\cdot P+Q_{2})\ (\text{mod}\ N)+2P)\);
* \(\text{offset}_{4}=(3+4(Q_{0}\cdot P+Q_{3})\ (\text{mod}\ N)+3P)\).  
The strides taken from one row to the next are determined by \(G=\mathit{mod}_{N}(4P\cdot\left[\frac{N}{4P}\right])\). We continue and construct each vector by concatenating the row G from it. Knowing there are \(4P\) rows in the transposed 2D matrix and 4 vectors, consequently, there are \(P-1\) concatenations to be performed.  
Note: In Figure 7, all row numbers must wrap around, keeping the index in range: \(0\leq\mathit{row}_{idx}\leq 4\cdot(P-1)\). Some parameter sets dictate a starting point for concatenation that is not the first DW of the first chosen row. The first DW for each vector\(i\) is defined by  
\[L_{k}=\left\lceil\frac{\text{offset}_{k}}{4P}\right\rceil;\ k=1,2,3,4\]  
Figure 8 depicts the virtual 2D matrix illustrated in Figure 4. In this example \(N=776\); \(P=39;Q_{0}=7;Q_{1}=0;Q_{2}=0;Q_{3}=0\). Hence, using the expressions above, one may obtain \(\text{offset}_{1}=3\); \(\text{offset}_{2}=42\); \(\text{offset}_{3}=397\); \(\text{offset}_{4}=436\); \(G=4\); \(L_{1}=0\) (always true since \(\text{offset}_{1}\equiv 3\)); \(L_{2}=0\), \(L_{3}=2\); \(L_{4}=2\).  
Figure 9 shows an example of the four result vectors in positions \(\text{offset}_{1}-\text{offset}_{4}\), which are the output of the concatenation phase and serve as the input for the ordering phase.  
Figure 7: Concatenated Vector\(i\); \(1\leq i\leq 4\).