esa-sceva/satcom-chunk-collection huggingface dataset:
# Radiator Enablers for Wireless Communication Evolution
## 3 Radiators' Novel Technologies, Design, and Implementation Issues
### Orbital Angular Momentum Antennas  
#### 3.4.1 General Description of OAM Systems  
[PERSON] et al. in 1992 (refs. [81; 82]) made a crucial discovery that Laguerre-Gaussian beams carry both spin angular momentum (SAM) and OAM and concluded that electromagnetic waves are capable of carrying OAM, too (ref. [82]). These electromagnetic waves' special characteristic is the helical phase wavefronts that can carry a wide spectrum of OAM modes. With the term OAM mode, we mean the integer number, most of the time assigned the symbol 1 or m, which indicates the number of wavefront twists within one wavelength (ref. [81]). Moreover, due to their orthogonality, it is possible to multiplex them in the same frequency channel without great interference; thus, the channel's capacity could be increased.  
Eventually, we prefer the usage of OAM instead of SAM due to the function of OAM waves, which can obtain an unlimited number of modes. To depict that, we can let \(1\in Z\) (refs. [81; 82; 83]), which means that they keep their orthogonality, and we can accommodate that through the channel's capacity enlargement, because different modes can coexist in the same channel and can also be processed separately on the receiver via demultiplexing, resulting in much greater data rates. Utilizing this can be beneficial due to resource saturation in RF communications and can also guide new frequency bands (ref. [81; 84]).
## 3 Methodology
### Structure of AWID3 Dataset
#### 3.1.1 Krack Attack  
The Krack attack has been noted as a potential security risk to the current encryption techniques used to preserve and protect Wi-Fi networks for the past 15 years. Publicly available information on the Krack attack includes information about the attack itself. There is no guarantee that every device will have a patch and be protected from these attacks coming from any networked point [38; 39]. The four-way handshake procedure, which is a crucial part of the IEEE 802.11 protocol has a serious weakness that allows any attacker to decode a user's communication without eavesdropping on the handshake or knowing the encryption key, according to [40]. This flaw results from the pairwise transient key (PTK) installation process' use of a particular message counter. It is vital to look at how keystreams are used in the encryption process to comprehend the decryption process. The plaintext and keystream are merged using the XOR (exclusive OR) technique to create the encrypted message that is sent from the client to the access point (AP). The PTK, which is derived using the AES (advanced encryption standard), is scrambled with several other factors to create the keystream. The vulnerability, though, only exists in the XOR operation's last phase. The logic flow of this step is connected to a fundamental mathematical feature that is exploited by the Krack vulnerability. Equation (1) shows how the plaintext (\(P\)) and keystream (\(KS\)), as shown in the paper, are combined to create the cipher text (\(E\)). The Krack hack uses this defect in the XOR method to decrypt the encrypted communications, putting the security of wireless networks using the IEEE 802.11 standard at risk.  
\[E=P\oplus KS \tag{1}\]  
An attacker could use two captured encrypted packets to decrypt them. Since the keystreams are identical, XORing the two ciphertexts results in the keystreams being canceled and leaving two plaintexts.  
\[E1=P1\oplus KS1 \tag{2}\]  
\[E2=P2\oplus KS2 \tag{3}\]  
\[KS1=KS2=KS \tag{4}\]  
Then:  
\[E1\oplus E2=(P1\oplus KS)\oplus(P2\oplus KS)=P1\oplus P2 \tag{5}\]  
If the attacker were to accurately estimate or know \(P1\), they could decrypt \(P2\). The well-known first message that the AP or client sends after connecting can be used for this. The key WPA2 stream was designed to stop this exploitation, but Krack researchers have found a way around it. Most of the keystream is made up of the static variables PTK, GTK, flags, MAC addresses, and counters. The only variable that alters when communications are encrypted is the packet number. Because every encrypted communication will have a different packet number and unique keystream, XOR cancellation is not conceivable [41].
# Utilization of Polymeric Materials toward Sustainable Biodiesel Industry: A Recent Review
## 2 Polymeric Biodiesel
### Production Techniques
For the catalyst type and ratio, H\({}_{2}\)SO\({}_{4}\), H\({}_{3}\)PO\({}_{4}\), and HCl acids were used to catalyze the esterification reaction. Literature reported usage of base catalysts for this reaction as well. Among all catalysts, H\({}_{2}\)SO\({}_{4}\) was \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Type of Polymer** & **Type of PHAs** & **Source of Carbon** & **Synthesis Microbe** & **References** \\ \hline \multirow{8}{*}{P3 HB} & \multirow{8}{*}{P3 HB} & Waste glycerol & \multirow{2}{*}{C. _nector_ DSM 545} & [37] \\ \cline{3-4}  & & Soy cake and molasses & & [38] \\ \cline{3-4}  & & Sugar of coconut, palm, rock, and toddy & C. _nector_ strain A-04 & [39] \\ \cline{3-4}  & & Soybean oil & _R. eutropha_ H16 & [40] \\ \cline{3-4}  & & Pineapple crude glycerol & _Bacillus firmus_ NII 0830 & [41] \\ \cline{3-4}  & & Cooking oil & _Burkholderia thailandensis_ & [42] \\ \cline{2-4}  & \multirow{2}{*}{PHHp} & Heptanoate & _P. putida_ KTOY06 & [43] \\ \cline{3-4}  & & PHV & Undecanoic acid & _hydrophilic_ 4 AK4 & [44] \\ \cline{2-4}  & \multirow{2}{*}{PHDD} & Sodium dodecanoate & _P. putida_ KT2440 & [45] \\ \cline{3-4}  & & PHO & Glycerol and sodium octanoate & _P. putida_ ATCC47054 & [46] \\ \hline \multirow{8}{*}{P3 HB-co-HA} & P3 HB-co-HA & Gluconate alkanoates & _Pseudomonas_ sp. 61-3 & [47] \\ \cline{2-4}  & \multirow{2}{*}{P3 HB-co-P4 HB} & P3 HB-co-P4 HBx & n-alkanoic acids & _R. eutropha_ H16 & [48] \\ \cline{1-1} \cline{2-4}  & \multirow{2}{*}{P3 HB-co-Hrk} & \multirow{2}{*}{Lauric acid, and oleic acid} & _A. luprobula_ & [49] \\ \cline{1-1} \cline{2-4}  & \multirow{2}{*}{P3 HB-co-P3 HV} & Lactose, glucose and galactose & _P. ludrogenovora_ & [50] \\ \cline{1-1} \cline{2-4}  & \multirow{2}{*}{P3 HB-co-P3 HV-co-P3 HHx} & \multirow{2}{*}{Dodecanoic acid and propionic acid} & Recombinant _A._ & \\ \cline{1-1} \cline{2-4}  & & P3 HHx & \multirow{2}{*}{4 AK4} & [51] \\ \cline{1-1} \cline{2-4}  & \multirow{2}{*}{P(3 HP-co-4 HB} & Glycerol & Recombinant _E. coli_ & [52] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Some examples of PHAs. the most frequently used to yield high percentage of HAME and HBME. The literature reported that the maximum yield of polymeric biodiesel can by synthesized with a catalyst ratio 10-15% [19; 50; 56]. For the temperature parameter, it is normal to adjust the reaction temperature around the boiling point of alcohol in order to avoid alcohol evaporation. [PERSON] et al. [21], [PERSON] et al. [22], and [PERSON] et al. [20] obtained the highest yield of HBME at 67 \({}^{\circ}\)C. However, [PERSON] et al. [35] got the maximum HBME at 100 \({}^{\circ}\)C. For time parameter, much time is required for this esterification process. According to [PERSON] et al. [21], the highest HBME percentage was produced from P3 HB at a reaction time 50 h. Further increasing time led to a decrease of HBME yield. Table 2 explores the previous studies regarding HAME and HBME production with optimum values.
###### Abstract  
In this work, we reported a comparative study of ZnO thin films grown on quartz glass and sapphire (001) substrates through magnetron sputtering and high-temperature annealing. Firstly, the ZnO thin films were deposited on the quartz glass and sapphire (001) substrates in the same conditions by magnetron sputtering. Afterwards, the sputtered ZnO thin films underwent an annealing process at 600 \({}^{\circ}\)C for 1 h in an air atmosphere to improve the quality of the films. X-ray diffraction, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectra, photoluminescence spectra, and Raman spectra were used to investigate the structural, morphological, electrical, and optical properties of the both as-received ZnO thin films. The ZnO thin films grown on the quartz glass substrates possess a full width of half maximum value of 0.271\({}^{\circ}\) for the (002) plane, a surface root mean square value of 0.50 nm and O vacancies/defects of 4.40% in the total XPS O 1s peak. The comparative investigation reveals that the whole properties of the ZnO thin films grown on the quartz glass substrates are comparable to those grown on the sapphire (001) substrates. Consequently, ZnO thin films with high quality grown on the quartz glass substrates can be achieved by means of magnetron sputtering and high-temperature annealing at 600 \({}^{\circ}\)C.  
ZnO thin films; quartz glass substrate; sapphire substrate; magnetron sputtering; annealing +
Footnote †: journal: Applied Physics and Materials, Wuyi University, Jiangmen 529020, Guangdong, China; [EMAIL_ADDRESS] (F.W.); [EMAIL_ADDRESS] (Z.G.); [EMAIL_ADDRESS] (P.H.); [EMAIL_ADDRESS] (Z.L.); [EMAIL_ADDRESS] (L.H.); [EMAIL_ADDRESS] (M.C.); [PERSON]AIL_ADDRESS]com (C.Z.)
## 3 Results and Discussion
### Thermal Behaviour, Kinetic Analysis, and Synergistic Effects
Figure 4: _Cont._  
Besides the above results from TG/DTG, indications for the existence of some synergistic effect can also be supported by the results of the Arrhenius kinetic analysis, which are presented in Table 2 (Arrhenius plots of the analyzed plastic wastes samples and blends with lignite are presented in Figure S2 of Supplementary Material). The activation energy of plastic waste is lower than the one of lignite. Of course, the reaction rate also depends on the pre-exponential factor A, which is orders of magnitude lower in the case of plastic waste than lignite. This lower value is counterbalanced by the lower activation energy resulting in a higher reaction rate for plastic waste. The blends exhibit even lower activation energy, suggesting the existence of synergistic effects. As mentioned in the Introduction, polymer oxidation involves a variety of chemical reactions. In the presence of lignite, such reactions are altered. In addition, the heat released by the combustion of some volatile products can be used for lignite decomposition leading to the shift of the peak in the DTG curve. Based on the above, the results of the co-combustion performance indices can be understood (Figure 4d). The results showed that the highest values of the CCI index were exhibited by PW. The blends, compared to lignite, exhibited higher CCI values, with the PW70 LIG30 samples exhibiting a higher value, followed by blends with 50% plastic and 30% plastic, respectively. The values of the \(\rm D_{i}\) and \(\rm D_{b}\) indices of PW were maximum (as absolute values). In the blends, the values were similar to the ones of lignite, but the differences among the single fuels and the blends are less pronounced for the case of \(\rm D_{i}\) and \(\rm D_{b}\). The results of the above-mentioned indices suggest that co-combustion enhances  
Figure 4: (**a–c**) Synergistic effect. DTG experimental vs. DTG theoretical blends: PW blends with lignite, (**d**) Synergistic effect. CCI, \(\rm D_{i}\) and \(\rm D_{b}\) indices. combustion. In general, a higher heating rate leads to increased values of the CCI index, which means that a better ignition and burnout performance is achieved [38].
# Enhancing Security of Online Interfaces: Adversarial Handwritten Arabic CAPTCHAs Generation
## 1 Introduction  
CAPTCHAs (Completely Automated Public Turing Tests to Tell Computers and Humans Apart) are employed on websites to distinguish between human users and automated bots. Initially, standard text-based CAPTCHAs used random alphanumeric strings that were easy for humans to read but difficult for computers to interpret [1]. However, with advancements in machine learning and computer vision, many text-based CAPTCHAs can now be solved by algorithms [2]. To enhance security, more recent CAPTCHAs systems incorporate computer vision tasks, such as image recognition [3].  
Since handwriting recognition remains a challenge for machines [4, 5], handwritten CAPTCHAs have been proposed to improve resistance against automated attacks [6]. Arabic handwriting, in particular, poses additional complexities due to its intricate character shapes, connected letters, and orientation dependence. These factors make modeling Arabic handwriting especially challenging [6]. Unfortunately, most CAPTCHAs in use today are limited to the Latin alphabet and are not well-suited for non-Latin scripts, such as Arabic [7].  
Applying adversarial examples to CAPTCHAs is one approach aimed at improving the security of CAPTCHA schemes. Although adversarial CAPTCHAs have been proposed previously in [8], the study does not specifically address Arabic CAPTCHA schemes.  
To bridge this gap, this paper proposes an approach for generating adversarial handwritten Arabic CAPTCHAs using deep learning techniques by simulating the complex character shapes, letter connections, and orientation dependencies characteristic of Arabic handwriting. Specifically, the focus is on creating CAPTCHA challenges that remain simple for humans to solve but pose significant difficulty for advanced machine learning models, even those with sophisticated recognition capabilities.  
In our approach, five adversarial techniques are applied to perturb the generated CAPTCHAs, namely, Expectation Over Transformation (EOT), Scaled Gaussian Translation with Channel Shifts (SGTCS), Jacobian-based Saliency Map Attack (JSMA), Immutable Adversarial Noise (IAN), and Connectionist Temporal Classification (CTC).  
The results demonstrated that JSMA provided the highest security level, with 30% of meaningless word CAPTCHAs completely unrecognized falling to 6.66% for meaningful words. From a usability standpoint, JSMA achieved the best accuracy, with 75.6% for meaningless words and 90.6% for meaningful words by JSMA technique. Overall, our approach offers an effective strategy for enhancing the security of Arabic websites and online interfaces against bot attacks.  
The remainder of the paper is organized as follows: The literature review is shown in Section 2. Section 3 explains the methodology. The results are shown in Section 4, while Section 5 discusses them. Finally, the paper is concluded in Section 6 with some future works.
# Energy and Environment-Aware Path Planning in Wireless Sensor Networks with Mobile Sink
## 6 Performance Evaluations
### Simulation Results
#### 6.3.3 Deadline Miss Ratio Evaluation
On the other hand, the preceding studies described in [18; 19; 22; 24] did not take into account real-time communications, in which tight latency requirements need to be satisfied. Additionally, they neglected to account for zone priority, which causes delivery delays that  
Figure 10: Influence of increasing average traffic rate on deadline miss ratio under the first scenario. are exacerbated by the multi-hop routing of crucial data connections. In turn, this causes a rise in the number of deadlines missed. A considerable percentage of packets are lost as a consequence of their failure to consider the dependability of the data transfer from the member nodes to the cluster heads, which also increases the delay that arises from packet retransmission; in turn, the proportion of deadlines missed will increase. 2. Deadline miss ratio evaluation under the second scenario  
For the second scenario, the effectiveness of the suggested technique is evaluated in this experiment and contrasted to earlier research [18; 19; 22; 24]. The experiment involves sending between three and nine packets per second. Figure 11 shows how the proportion of missed deadlines changes in relation to traffic volume. This figure demonstrates that the suggested method increases average network traffic rate while delivering the lowest deadline miss ratio among the available solutions. This is because the suggested method uses a modified environmental effect measure to find safer routes away from risk areas for the mobile sink and urgent data transfer. Built-in data paths are less susceptible to environmental interruption. As a result, there is less packet loss and retransmission during packet transit, which lowers delivery delay. This demonstrates the superiority of the suggested approach. The reasons the suggested method performed better than other algorithms in the first case are revealed in the remainder. Meanwhile, the previous works performed in [18; 19; 22; 24] cannot make prompt reactions to the environmental changes; therefore, they cannot provide sustainable message delivery services under harsh environmental conditions. This increases the packet loss rate, resulting in more delivery delays due to the retransmission of lost packets and increasing the deadline miss ratio.
## Appendix A \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**No** & **Parameter** & **Value** & **Unit** & **Reference** \\ \hline Source & & & & \\ \hline
1 &
\begin{tabular}{c} Radionuclide \\ concentration \\ \end{tabular} & 0.037 & Bq\(\cdot\)g\({}^{-1}\) & Initial concentration (=1 pCi\(\cdot\)g\({}^{-1}\)) \\ \hline Transport factors & & & & \\ \hline
2 &
\begin{tabular}{c} Number of \\ unsaturated zones \\ \end{tabular} & 1 & - & NUREG/CR-7267 [19] \\ \hline
3 &
\begin{tabular}{c} Time since placement \\ of material \\ \end{tabular} & 0 & year & NUREG/CR-7267 [19] \\ \hline
4 &
\begin{tabular}{c} Groundwater \\ concentration \\ \end{tabular} & 0 & pCi\(\cdot\)L\({}^{-1}\) & NUREG/CR-7267 [19] \\ \hline
5 & \begin{tabular}{c} Leach rate \\ \end{tabular} & \
\begin{tabular}{c} (Nuclide specific) \\ \end{tabular} &
\begin{tabular}{c} year\({}^{-1}\) \\ \end{tabular} & NUREG/CR-7267 [19] \\ \hline
6 & \begin{tabular}{c} Solubility limit \\ \end{tabular} & \
\begin{tabular}{c} (Nuclide specific) \\ \end{tabular} &
\begin{tabular}{c} mol\(\cdot\)L\({}^{-1}\) \\ \end{tabular} & NUREG/CR-7267 [19] \\ \hline
7 & \
\begin{tabular}{c} Use plant/soil ratio \\ \end{tabular} &
\begin{tabular}{c} Unchecked \\ \end{tabular} & - & NUREG/CR-7267 [19] \\ \hline \multicolumn{4}{c}{Calculation parameters} \\ \hline
8 & Times for calculations &
\begin{tabular}{c} 1, 3, 10, 30, 100, \\ 300, 1000 \\ \end{tabular} & year & NUREG/CR-7267 [19] \\ \hline \multicolumn{4}{c}{Contaminated zone parameters} \\ \hline
9 &
\begin{tabular}{c} Area of \\ contaminated zone \\ \end{tabular} & 49,518 & m\({}^{2}\) & Area of Wolsong NPP unit 1 [14] \\ \hline
10 &
\begin{tabular}{c} Thickness of \\ contaminated zone \\ \end{tabular} & 0.15 & m & Case of Rancho Seco NPP [3] \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Input parameter database for RESRAD-ONSITE code employed in the present work.
# Blockchain-Based Distributed Patient-Centric Image Management System
## 4 Overview of the PCIM System
### System Model  
The participants of the proposed PCIM system are defined below:  
_Patient_: Patients are the owners of their medical images. A patient is required to create PCAC-SC and store this SC in the Ethereum blockchain. The patient is responsible for defining the access right to the images in the IPFS network. This definition is done within his/her own PCAC-SC.  
_Radiologist_: A radiologist is able to generate medical images for a patient. The prime responsibility of the radiologist is to upload the patient encrypted medical images to the IPFS network and to verify the patient initial transaction on blockchain.  
_Image Requestors_ (_IRs_): Clinicians, medical institutions, research groups, insurance companies, and general practitioners interested in accessing patient medical images are all considered as image requestors _IRs_. The patient can grant access privileges to any _IRs_ based on the authorization policy defined in PCAC-SC.
# Requirements and Hardware Limitations of High-Frame-Rate 3-D Ultrasound Imaging Systems
## 1 Introduction
This study highlights that, although the ULA-OP 256 was so far demonstrated sufficiently efficient to process hundreds of images per second in real-time [27; 31; 38], the adopted data transfer topology was not optimal in all cases and determined a performance \"bottleneck\". A different topology has thus been proposed and implemented to balance the data transfer between the boards of the system. When experimentally compared to the previous topology for different HFR imaging modalities, the new topology shows an average three-fold increase in frame/volume rate, with a peak of 4400 frames/s and 510 volumes/s. The paper is organized as follows. Section 2 defines the metrics involved in the reception stage of hardware-based scanners and calculates the corresponding digital devices' requirements for sample 2-D and 3-D imaging modes. Then, the original and the updated communication topologies adopted in ULA-OP 256 are described. Section 3 describes the experiments performed with the scanner, while Section 4 shows the corresponding results. A discussion and conclusions are reported in Section 5.
## 1 Introduction  
Immediate implant placement and provisionalization at the time of extraction in the esthetic zone is today a common treatment modality [1]. The literature outlines the non-interventionist healing process of a post-extraction socket, or in combination with a socket preservation technique, including bone and/or soft tissue grafting, as well as with or without simultaneous implant placement [2; 3; 4; 5; 6; 7]. While many protocols have been suggested to achieve the establishment of an esthetic and natural result post extraction in the anterior region, challenges persist [8; 9; 10]. Primary among the challenges faced by clinicians are predictability and reproducibility of esthetic outcomes. Especially, as they relate to the volumetric changes that occur to the labial plate of the socket housing post-extraction, both in the bucco-lingual and apico-coronal aspect. These volumetric osseous changes in turn often result in labial gingival recession, as well as negative optical manifestations of the soft tissue due to concavities. Studies have also shown successful results in intact type I sockets, ideal bone and soft tissue profiles ([PERSON] and [PERSON] 1993) at onset, utilizing a combination of bone replacement graft (BRG) and a temporary prosthesis at the time of extraction and implant placement [11; 12; 13]. In addition, simultaneous connective tissue grafting grafting in order to increase the stability and predictability of an esthetic outcome have also been suggested [14; 15]. Furthermore, there is also evidence that in type I, the labial root fragment can be maintained to biologically stabilize the labial osseous and soft tissue (Partial extraction therapy) [16; 17]. However, most immediate implant treatment protocols specifically address only type I sockets, where no hard or soft tissue deficiencies exist prior to extraction [18; 19].  
Through two case reports, the purpose of this article is to present a new esthetic zone protocol for immediate placement and provisionalized of implants in both class I sockets, as well as class II sockets with a Miller Class I recession deficiencies. Novel steps are introduced and existing clinical protocols are modified, for both the surgical and restorative interventions, with the goal of predictably achieving an optimal result utilizing simpler and less invasive therapeutic protocols 18, including the step-by-step description and application of the Marginal Migration Concept (MMC) in a Class II site [18].
## 3 Throughput Performance Limits of Multimode Underwater Acoustic Networks
### The Method of Solving the Model  
In this paper, we utilize a combination of dynamic programming and greedy algorithms to iteratively solve the Markov decision process, ultimately obtaining the throughput performance of a multimode underwater acoustic network. The key components of our approach include policy evaluation, policy improvement, and policy iteration, which are discussed in detail below.