esa-sceva/satcom-chunk-collection huggingface dataset:
# Image Encryption Algorithms: A Survey of Design and Evaluation Metrics
## 2 Image Encryption Algorithms  
Digital images are electronic files that consist of two-dimensional arrays of numbers with variable sizes and channel numbers (i.e., one channel for gray-scale images, three channels for color images, and four channels for color images with a transparency channel) that store pixel values. Each pixel represents a specific color. A digital image, \(I\), is defined by size, \(H\times W\times nc\), where \(H\) is the height, \(W\) is the width, and \(nc\) is the number of channels. Images usually contain private and personal information, such as personal and legal documents, medical images, military images, etc. When these types of images are shared over the internet or on an unsecured network, these images could be compromised by unauthorized access. Furthermore, most digital images tend to contain high redundancy due to the correlation between neighboring pixels. Image encryption algorithms aim to ensure the security of the image from unauthorized access by encrypting the plaintext image and producing a cipher image that can only be decrypted by the intended users. Image encryption algorithms use the confusion and diffusion [2] principle to produce cipher images and reduce the correlation between neighboring pixels. Confusion is attained by changing the values of each pixel in a digital image by a substitution map, where the values of each pixel in a plaintext image are changed by a substitution map such as an AES S-Box. Diffusion is achieved by changing the plaintext image pixels' location within an image itself using mathematical permutation operations. Diffusion helps in reducing the correlation between adjacent pixels that are present in the plaintext image. In image encryption, confusion and diffusion are controlled using a key or a set of keys to obscure and permute the plaintext image to produce the cipher image. Researchers have proposed a multitude of image encryption algorithms in the past decades. This section presents a review of image encryption algorithms based on the techniques used. Figure 1 illustrates the seven different approaches based on the techniques used.  
Figure 1: Different approaches to image encryption based on the used techniques.
###### Abstract
In terms of model construction, the ANN model for storage tank risk analysis, based on the structure and principles of Fuzzy DFT, can better account for dependencies between events compared to traditional models, thereby simplifying the calculation process and significantly improving computational efficiency and accuracy. Additionally, the development of an LSTM model for tank accidents is another key advantage. Unlike traditional static models, this LSTM model can quickly predict the dynamic changes in the failure probability of the top event (TE) over time, providing a real-time analytical tool for storage tank safety management. In terms of implementation, the method uses widely available software tools. Data processing and model construction are primarily carried out in the Python 3.7 programming environment. Libraries such as pandas and numpy are used for data processing, scikit-learn for data preprocessing, including normalization and data splitting, while deep learning frameworks like PyTorch 1.13 or Keras 2.11 are employed to construct and train the ANN and LSTM models. These tools have user-friendly interfaces and powerful functionalities, ensuring the smooth implementation of the proposed method and making it easy to use and apply in practical scenarios. Overall, this new method represents a significant advancement in storage tank accident probability analysis, providing the industry with a more reliable and efficient solution. 2 Model Construction for Quantitative Probability Calculation Based on Fuzzy DFT and Neural Networks  
The process of the proposed quantitative probability calculation method for hazardous chemical storage tank accidents based on Fuzzy DFT and neural networks is shown in Figure 1. First, the causal factors of the accident are determined through analysis of accident reports and other sources, and a Fuzzy DFT model for hazardous chemical storage tank leakage accidents is constructed. Corresponding ANN and LSTM models are then built for the DFT model to calculate the failure probability of the top event and the temporal changes in this probability. For the basic events in the DFT model, the failure probabilities are calculated using fuzzy set theory, and the obtained failure probability data are augmented using the Bootstrap method to create a dataset for the storage tank neural network model. This data-driven approach reduces the influence of expert subjective judgment. Additionally, risk data for each accident factor, changing over time, is collected to construct a time-series dataset. Finally, the dataset is input into the constructed ANN model and time-series LSTM model to compute and quantitatively analyze the failure probability of the storage tank accident.
## 4 Conclusions  
This study investigated the TPC, TFC, radical scavenging effects, and quantitative and qualitative analyses of metabolites to optimize the extraction conditions of _E. globulus_ leaves. The TPC of _E. globulus_ leaf extract was highest in the 10-70% ethanol extracts. The TFC showed a higher aspect as the ratio of relatively non-polar solvent to ethanol increased. The most antioxidative condition against DPPH radicals was the 30% ethanol extract, while the best antioxidant efficacy for ABTS radical scavenging activity was observed under 30% and 50% ethanol extraction conditions. Moreover, LC-Q-TOF/MS analysis of the _E. globulus_ leaves extracted using 30% ethanol identified eight predominant phytochemicals, including salicylic acid \(\beta\)-D-glucuronide (**1**), chlorogenic acid (**2**), epicatechin (**3**), 2''-O-galloyhperin (**4**), isoquercirtin (**5**), isornapontin (**6**), quercetin (**7**), and quercetin-3-O-glucuronide (**8**). The most predominant metabolites were epicatechin, a phenolic, and 2''-O-galloyhperin, a flavonoid, in the 50% ethanol extract. Overall, the results suggest that the extract conditions of _E. globulus_ leaves play a significant role in determining the phytochemical composition as well as the antioxidant potential.  
J.Y.P.: conceptualization, formal analysis, and investigation; J.Y.K. ([PERSON]) and Y.G.S.: formal analysis; S.D.K.: conceptualization and resources; S.W.L. and K.D.K.: Writing--review and editing; J.Y.K. ([PERSON]): supervision and overall research. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean Government (MSIT) (No. 2021R1A5A8029490 and No. 2022R1F1A1063786).  
Not applicable.  
The authors declare no conflict of interest.
## 1 Introduction  
Substituted pyrimidine rings as scaffolds are of great interest for medicinal chemists being a part of many biologically active compounds [1, 2]. The pyrimidine moiety is present in many natural compounds [3] (e.g., nucleic acids, alkaloids, folic acid, etc.) as well as synthetic analogs and also in approved drugs on the market, e.g., anticancer [4, 5, 6], antiviral [4, 7], antibacterial [8], antilipidemic [9], anti-inflammatory [3, 10], and antimalarial agents (Figure 1). Large number of synthetic methods have been described for the preparation of pyrimidine-based compounds [11, 12, 13, 14, 15, 16]. Cyclocondensation between guanine-dine, amidine or thiourea derivatives and 1,3-diketones or 1,3-diesters is the most classical method for the synthesis of the main pyrimidine core [15, 17], whereas one of the approaches to prepare substituted pyrimidine rings is via halogenated pyrimidines [18, 19, 20], which are greatly commercially available. The most common reactions involving various halogenated pyrimidines are cross-coupling reactions since pyrimidine ring is an electron-deficient aromatic system being far more reactive in comparison with analogous benzene halides [17, 20]. Halogenated pyrimidines are thus very convenient substrates for substantial assortment of nucleophilic aromatic substitutions. Suzuki coupling of halogenated pyrimidines with boronic acids has been a commonly used approach for the preparation of a diverse set of substituted pyrimidines [20].  
Polyhalogenated pyrimidines are commonly used substrates in cross-coupling reactions since each substituent could be added sequentially to a pyrimidine ring due to the intrinsic differences in reactivity at different positions [21, 22, 23, 24]. In case of commonly used and commercially available 2,4-dichloropyrimidines, the regioselectivity preference in a Suzuki cross-coupling reaction was observed for C4-position due to the favored oxidative addition of palladium into the C4-chlorine bond [22, 24, 25]. Some anomalies have been observed, favoring C2 position over C4, mainly due to the steric reasons when additional substituents are present at other positions, i.e., C5 [24]. In the publication from [PERSON] and [PERSON] in 2010, efficient synthesis of diarylated pyrimidines via regioselective double Suzuki coupling of 2,4-dichloropyrimidine was presented [21]. Similarly, the reaction occurred at the C4-position when 2,4-dichloropyrimidine or 2,4,6-trichloropyrimidine were coupled with alkenyl-boronic acids [26].  
The aim of our study was to develop a quick, efficient, and regioselective synthetic procedure for substituted pyrimidines at position C4 from readily available 2,4-dichloropyrimidines via Suzuki coupling with a diverse set of aryl and heteroaryl boronic acids. The selection of appropriate solvents, catalysts, and reactions conditions (temperature, time) was systemically performed. Last, but not least, the optimal procedure was also transferred to a microwave reactor and further optimization (i.e., temperature, reaction time catalyst loading) was carried out.
# Design of Wideband Decoupling Antenna Array for 5G Smartphones at N77/N78/N79/WLAN 5 GHz Bands
## 2 Design and Evolution of Antenna Systems  
### Configuration  
As shown in Figure 1, the system consists of a ground plane of 150 mm \(\times\) 70 mm with a ring bezel of height 6 mm. The thickness of the substrate is 0.8 mm, the substrate material is FR-4, the relative permittivity is 4.4, the relative permeability is 1, and the loss tangent is 0.02. The antenna element consists of a coupled-feeding structure formed by the inner L-type branch of the substrate and the external radiators of the bezel. The use of coupled-feeding structure is equivalent to adding an equivalent capacitance, which helps to expand the bandwidth. In addition, fine-tuning the geometry of the L-shaped coupling-fed branch can easily realize the impedance matching. Two antenna elements are symmetrically placed to form an antenna pair. To improve the isolation between the antenna pairs, a strip-shaped DGS is etched on the ground plane at the center of the antenna pairs. To improve the isolation between the antenna elements on the adjacent side of the two antenna pairs, the same strip-shaped DGS is etched in the middle of the long side of the system, and two decoupling strips are extended from the ground plane to the frame.
## 3 Simplification of CDM
### Coupling Effect Analysis  
The coupling effect is analyzed by the amplitude-frequency characteristic of CDM, which is obtained by linearization at equilibriums [31].  
\[\begin{split}&\Delta\dot{\xi}(t)=A_{k,0}\Delta\xi(t)+B_{k,0}\Delta u (t)\\ & A_{k,0}=\left.A\right|_{\xi_{0},u_{0}}=\left.\frac{\partial f}{ \partial\xi}\right|_{\xi_{0},u_{0}},\left.B_{k,0}=\left.B\right|_{\xi_{0},u_{ 0}}=\left.\frac{\partial f}{\partial u}\right|_{\xi_{0},u_{0}}\\ &\Delta\xi(t)=\xi(t)-\xi_{0}(k),\left.\Delta u(t)=u(t)-u_{0}(k), \left.\xi=\left[v_{x},v_{y},\omega\right]^{T},\right.u=\left[F_{T},\delta_{f} \right]^{T}\right.\end{split} \tag{8}\]  
To evaluate the influence of inputs to the outputs at the same scale, the transfer function is normalized according to the analysis results about natural driving conditions in Section 2.1:  
\[\begin{split} G(s)^{\prime}=\left[\begin{array}{cc}\frac{ \Delta v_{x}(s)}{\Delta F_{T}(s)},\frac{\overline{F}_{T}}{\overline{v}_{x}}& \frac{\Delta v_{x}(s)}{\Delta\delta_{f}(s)},\frac{\overline{\delta}_{f}}{ \overline{v}_{x}}\\ \frac{\Delta\omega(s)}{\Delta F_{T}(s)},\frac{\overline{F}_{T}}{\overline{ \omega}}&\frac{\Delta\omega(s)}{\Delta\delta_{f}(s)},\frac{\overline{\delta }_{f}}{\overline{\omega}}\\ \overline{v}_{x}=30\left.\mathrm{m}/\mathrm{s},&\overline{F}_{T}=m \cdot a(v_{x}),&\overline{\delta}_{f}=\delta(v_{x}),&\overline{\omega}= 38\left.\mathrm{deg}/\mathrm{s}\right.\end{array}\right]\end{split} \tag{9}\]  
where \(s\) is the Laplacian operator, \(\delta(v_{x})\) and \(a(v_{x})\) are obtained from the \(3\sigma\) boundary in Figure 2a,c, respectively.  
Since the closed-loop system composed of the human and vehicle is a low-pass one with a cut-off frequency smaller than \(1\) Hz [32], only the low frequency band is considered. The vehicle state space under natural driving conditions is divided into \(22,500\) equilibrium points with the step size, \(0.2\), for \(v_{x}\in[0,\ 30]\)\(\mathrm{m}/\mathrm{s}\) and \(\delta_{f}\in[0,\ 30]\) degree.  
Figure 6: Comparative simulation results: (**a**) longitudinal speed; (**b**) yaw rate; (**c**) coupling force in longitudinal direction; (**d**) coupling force in lateral direction.
# The Blockchain Oracle Problem in Decentralized Finance--A Multivocal Approach
## Appendix A  
### Tellor Oracle  
Tellor is an oracle system specifically made to fetch data about exchange rates. On the Tellor platform, miners compete to add data to an on-chain data bank. Users that need updated data about exchange rates make queries on the data bank, and for each query, they leave a tip in \"Tribute\" (TRB), the Tellor native token. Every 5 min, the Tellor smart contract groups the five queries with the higher tips and creates a PoW for miners to solve. The first five miners to provide the off-chain data and the solution to the PoW are rewarded with newly minted TRB and tips. The oracle resolves the value once five reports for the same feeds arrive. To ensure fair competition, in order to participate in the PoW,the miners must freeze in the Tellor smart contract a deposit (500 units of TRB, around $35,000) which is lost in case of a successful dispute by TRB holders. Data-submission cycles last 5 min and are called blocks. Since only one feed is provided by the oracle every 5 min, the Tellor oracle does only provides 288 price updates per day. After prices are settled, a dispute round begins, which lasts for two days. During that time, other TRB holders can submit a different value for an already confirmed price feed depositing double of the stake (1000 TRB). When a dispute is initiated, the dispute round is prolonged for an additional day until no more disputes for the same feeds are received. To ensure also the fairness of wealth distribution, on the Tellor ecosystem, each miner cannot win two consecutive rounds (blocks), and the minimum waiting time is 15 min (three blocks). Security mechanisms on the Tellor ecosystem are mainly toward the exclusion of faulty oracles in favor of trusted ones. The PoW also proves to be efficient against Sybil attacks that would be nearly infeasible due to the computing power required. The Tellor dispute mechanism is summarized in Figure A1[132].
# Numerical Simulation of Polymer Solutions in a Single-Screw Extruder
## 1 Introduction
In contrast with the standard flat-plate model of the unwound screw channel (2D), this hydrodynamic problem is solved in a three-dimensional formulation in [17; 26]. Authors of the papers consider mathematical modeling of the flow in the metering zone of a plasticizing extruder. The objective of the study was the melting of the polymer composition based on polyethylene. Work [27] presents the results of three-dimensional numerical simulation of the polymer melt flow in a channel with a screw (extruder). In this case, the polymer melt was considered as the Newtonian fluid, which does not correspond to the real rheological behavior. In the model presented in [28], the continuous penalty finite element scheme and the power-law model were used to solve the basic equations of continuity and momentum in a three-dimensional Cartesian coordinate system. Work [2] presents the three-dimensional modeling of the wood-plastic composites melt flow in the metering section of the single-screw extruder. The paper notes that the extrusion of these polymers is significantly different from the extrusion of plastics. Therefore, it is important to consider that the rheological behavior of different polymers can vary significantly. Some results of three-dimensional modeling of heat and mass transfer under laminar flow of the low-density polyethylene in a single-screw extruder is presented [29]. The Carreau-Yasuda model, which includes five parameters, was used to describe the rheology behavior of the polymer melt. However, the drawback of this work is the lack of analysis of mesh convergence; numerical results were obtained using a coarse mesh. Work [24] discusses the study of secondary flows (Moffatt eddies) arising in the metering zone of the extruder. Open-source computational fluid dynamics package OpenFoam was used for numerical studies. The rheological properties of shear-thinning fluid were described with the Carreau model. The article [16] presents a three-dimensional model of a single-screw extruder. The partial rotational fraction has been implemented with the finite element. However, as noted by the authors, the extension of the developed method in viscoelastic flow simulations is not possible. The aim of this work is to study the structure of the polymer solutions flow in a single screw extruder using 3D modeling. The 0.5% polyacrylamide (0.5% PAA) and 1.5% sodium salt of carboxymethyl cellulose (1.5% CMC) are used as working fluids. This study is part of an ongoing study whose goal is to develop a mathematical model to describe the flow of viscoelastic fluids in a single-screw extruder
# Automated Modal Analysis Using Stochastic Subspace Identification and Field Monitoring Data
## 3 Proposed Procedure  
To implement SSI while considering adequate user-defined parameters for automated OMA, three steps are proposed instead of constructing the block Hankel matrix straightforwardly after the measurements are collected. In particular, spurious modes and unsteady stability diagrams dramatically affect identification results in field applications. These steps include data preprocessing, matrix construction and decomposition, and system realization, as shown in Figure 1. Herein, the proposed procedure is numerically illustrated using a simulation study of a shear-type building structure. The fundamental frequency (or lowest frequency), \(f_{0}\), is assigned as 1 Hz, and the damping ratios of the structural system for all modes are assigned as 2%. To focus on the effectiveness of the procedure, the measurements are assumed to be noiseless and the full measurement is sampled with 50 Hz.
# Non-Magnetic Circulator Based on a Time-Varying Phase Modulator
## 2 Gyrator Design  
The gyrator is an essential part of the circulator, which is a non-reciprocal two-port device [19]. As shown in Figure 1d, the circulator can make a phase difference of 180\({}^{\circ}\) between the propagating and opposite transmission of the signal. In this section, the new concept of TVPM is present, which is used to break the time-reversal symmetry. The demands of the control signal in the composed gyrator circuit are investigated. The two unavoidable losses in the composed gyrator circuit using the TVPM are studied.
## 2 Background
### Named Data Networking and Artificial Intelligence  
The current TCP/IP network's security, mobility, and other issues are addressed by NDN, which serves as a prototype for the future network by replacing the IP address with the name of the content. NDN is considered a promising new Internet paradigm to replace the TCP/IP hourglass model's \"thin waist.\" A new solution has been obtained by merging NDN technology with AI. With its low power consumption and rapid speed, AI is ideal for IoT systems that require local real-time data analysis. Software implementation of noise distribution normalization [5] adds Gaussian distributed noise, resulting in differential privacy for edge AI. Traffic across the core network and inference latency can be reduced by deploying AI at the edge of networks that are in close enough proximity to the extraction of a large amount of information [30]. Several articles have embedded medical application systems on the IoT, including smartwatches, and smart HVAC systems, with the aim of reducing human effort [31]. A brief discussion was presented by [PERSON] et al. [32], elaborating on the use of the Internet of Medical Things using AI technology. Analyzing local data in real time for the IoT systems is made possible by edge AI, which allows for a low-level operation while protecting user privacy. AI technology has improved data privacy access, based on a large number of data and mobility systems on NDN [33].  
In the context of continuing network location changes, mobility refers to the capacity to maintain a unified connection with network entities in AI. Existing host-dimension solutions have exhausted all of the design options and are at a standstill when it comes to new performance advances. Trajectory-driven reachability updating and topology-driven intermediate placement have been proposed to improve overall mobility assistance performance [34]. Figure 3 shows an example of an NDN application that is embedded with AI mobility in e-health technology.  
In terms of security, NDN data caching, which is a significant aspect of the technology, can be greatly reduced. Identifying a viable mitigation strategy when NDN routers are exploited by attackers is difficult. ACO [35] has been proposed for probing a safety trans  
Figure 3: NDN AI mobility using smart technology.  
mission path and adjusting content retrieval, gathering information about all routers on a network, and bypassing bad routers, thereby preventing the bad routers from continuing to disseminate illegal content and minimizing substance contamination by removing bogus data packets from a cache store during the path traversal. A reactive attack uses content fetch time to track down the items that people are looking for. A proactive attack [36] caches an item before checking whether the victim requests that item.