esa-sceva/satcom-chunk-collection huggingface dataset:
## Article  
Model of the Selective Laser Melting Process-Powder Deposition Models in Multistage Multi-Material Simulations  
**[PERSON]**\({}^{\copyright}\)  
Faculty of Metals Engineering and Industrial Computer Science, AGH University of Krakow, Al. Mickiewicza 30, 30-059 Krakow, Poland; [EMAIL_ADDRESS]; Tel.: +48-692-983-805  
**Featured Application: This holistic model for full-scale modeling of the selective laser melting process can be applied for the study, development, and design of multi-material processes. It can be adapted to other powder-bed fusion processes.**  
This paper presents one of the final stages in the development of a holistic model of the selective laser melting (SLM) process. The holistic model developed previously allows for modeling of only one stage of SLM, which limits simulations to one cycle with one material. The lattice Boltzmann method is applied for simulation of laser treatment, melting, fluid flow, and solidification. Several models of powder bed generation were developed within the framework of the holistic model and are described in this paper. They were developed on the basis of static and dynamic physical principles with the use of cellular automata, their own code, and the Unity\({}^{\copyright}\) platform. They employed continuous and discrete particle representation and incorporated a model of powder deposition with particles of atomized or arbitrary shape. The closing of the external simulation circuit, which contains the powder bed generation model, cycle initialization, its realization by the model based on the Lattice Boltzmann Method (LBM), and the powder removal model, allows us to finish one simulation cycle of laser treatment and initialize the next, thereby enabling multistage multi-material simulations. The simulation results of the multistage SLM process with the Ti-6 Al-V alloy and bioactive glass are presented in this paper. These simulation results confirm the possibility of modeling several SLM stages with two different materials. The holistic model can be used for simulation, design, and optimization of multistage, multi-material SLM processes.  
additive manufacturing; 3D printing; powder bed fusion; selective laser melting; powder deposition model; modeling; multistage simulation; lattice Boltzmann method
# Worldwide Coverage Mobile Systems for
## 4 Ku-Band Antennas Design Techniques
### Planar Antennas
\begin{table}
\begin{tabular}{l c} \hline \hline
**Feature** & **Value** \\ \hline
10 dB return-loss bandwidth & about 54\% (11.7–19.8 GHz) \\
3 dB gain bandwidth & 42.3\% (11.7–17.2 GHz) \\
3 dB axial-ratio bandwidth & about 29.3\% (12.4–16.8 GHz) \\ overlapped bandwidth of the three & 29.3\% \\ maximum CP gain & 11.45 dBic at 14 GHz \\ gain enhancement & about 2.1–5.2 dB (compared with the unloaded type) \\ \hline \hline \end{tabular}
\end{table} 
Table 19: Features of the circularly polarized-magneto-electric dipole antenna (CP-MEDA) antenna. substrate is used in order to construct the antenna. On this substrate, several high permitivity dielectric strips are layered to form the antenna structure. This physical construction results in a wide bandwidth and high gain. An improvement introduced in this design is that, instead of using just one dielectric strip, a couple of dielectric strips are layered on the coupling slot constructed with 45\({}^{\circ}\) inclination. This set-up makes the generation of the circular polarization required for the transmission/reception easier. In this case, the design decision was aimed at generating three circular polarization modes which are closely coupled. With the aim of smoothing the application in the antenna array, it is further introduced the design of a cavity-backed antenna. The authors proposed implementing, measuring, and testing a sub-array prototype in order to verify the design and simulation results, with the main features being shown in Table 20.  
A reflect-array antenna that is specifically designed for satellite communications at the Ku band applications composed of \(3\times 3\) elements is introduced in [35], where the basic element is a single layer structure that is linearly polarized. This antenna is aimed at communications at 12.5 GHz (within the Ku band). The tests implemented to verify the antenna features demonstrate that this reflect-antenna shows a high gain and a good behaviour of the phase properties. It is conclude that this antenna is appropriate to be used as a reflector. The methodology to achieve the best performance was based on the design of several basic elements, evaluate each one in order to choose those with superior features and, afterwards, the array is constructed. To feed the antenna array, a source patch is used, which is positioned at the appropriate distance (5\(\lambda\)/4).
# Screening of Plants and Indigenous Bacteria to Improve Arsenic Phytoextraction
## 2 Materials and Methods
### Isolation of Arsenic-Tolerant Bacteria  
Indigenous arsenic-tolerant bacteria were isolated and subsequently used to support plant performance. Small aliquots of bulk and rhizospheric native plant soil from the contaminated soil of the external area were resuspended in sterile milli-Q water. After a few hours of incubation at room temperature, 100 \(\upmu\)L of serial ten-fold dilutions were plated on LB agar supplemented with 100 mM of sodium arsenate (Na\({}_{3}\)AsO\({}_{4}\)). After 4 days at 30 \({}^{\circ}\)C, several colonies were visualized. About 100 colonies were randomly selected and propagated to obtain pure cultures.
# A Comprehensive Survey on Privacy-Preserving Techniques in Federated Recommendation Systems
## 1 Introduction
### Our Contribution  
Compared to the existing surveys, this survey paper provides the impact of FRSs on privacy-preserving techniques in big data. It presents a comprehensive review of the main challenges and existing approaches to enable data sharing while preserving user privacy. Furthermore, it compared various privacy-preserving techniques, including differential privacy, secure multiparty computation, homomorphic encryption, tokenization, anonymization, and pseudonymization. Furthermore, this survey provides an overview of the targeted applications and industry of FRSs. Moreover, a detailed description of the public datasets used in FRSs is provided, highlighting the unique challenges posed by big data sharing. Finally, this survey paper provides real-world challenges for future research directions.  
The rest of the paper is organized to provide an in-depth exploration of the field of FRSs. Section 2 provides the necessary overview of the research. Section 3 delves into the details of privacy-preserving techniques used in this area. Section 4 examines the applications and industries that are targeted with FRSs. Section 5 looks at the publicly available datasets for FRSs. Section 6 delves into the future directions and challenges that can be faced in real-world applications. Lastly, Section 7 concludes the survey and provides an overall summary of the research.
# A Novel Approach for Fraud Detection in Blockchain-Based Healthcare Networks Using Machine Learning
###### Abstract
Reinforced Learning: The key characteristic of this type is collecting and enhancing knowledge to communicate with external entities. After that, it assigns a penalty or reward according to the action taken [9]. ML can solve problems using different methods, such as clustering, classification, and regression. Classification methods are preferred to manage security and privacy problems in blockchain networks. This paper addresses security and privacy issues in a blockchain-based smart healthcare system due to the sensitivity of medical data and its vulnerability to cyber-attacks. A system architecture is capable of detecting attacks and fraudulent transactions in blockchain networks based on ML algorithms. This system is composed of two stages. The first stage checks the medical data gathered by sensors before inserting it into the BC. Hence, abnormal ones are blocked from being processed by the BC nodes. The second stage verifies the legitimacy of transactions and eliminates the suspected ones. The proposed system is implemented using six different ML algorithms. A performance evaluation of these algorithms with respect to many metrics is conducted to choose the best solution that tackles BC security challenges. We demonstrate that the proposed ML-based system achieved high levels of accuracy, recall, F1-score, precision, execution time, ROC-AUC, and scalability, suggesting its effectiveness in detecting and preventing fraud within the blockchain network. According to the results of experiments conducted on two datasets and after the pre-processing and feature selection, the Random Forest achieved the highest accuracy, execution time, and scalability. Thereby, it was considered the best solution among the rest of the algorithms for tackling the research problem. After a security analysis phase, we demonstrate that the proposed system is able to enhance the security and reliability of blockchain-based healthcare applications and networks by detecting and preventing several known attacks. The rest of the paper is organized as follows. In Section 2, a brief review of related works on detecting intrusion and malicious activities in blockchain networks is presented. Section 3 details the proposed system, which can detect and protect the blockchain from attacks and fraudulent transactions. Section 4 evaluates the proposed system using various ML algorithms and with respect to many metrics. Section 5 analyses the security of the proposed system. Finally, the conclusion and some future work directions are drawn in Section 6.
# Numerical Study on the Yaw Control for Two Wind Turbines under Different Spacings
###### Abstract
(2018) studied six kinds of wind farm layouts and analyzed the effects of induction control, yaw control and combined induction-yaw control. It was found that yaw control is suitable for the aligned layout wind farm. [PERSON] et al. (2019) systematically studied the physical characteristics and effectiveness of active yaw control under different wind conditions with wind tunnel experiments and a newly developed analytical model of wind farms. They found that the spacing of turbines and other factors would influence active yaw control. When there are multiple turbines, the optimal yaw angle continuously decreases from upstream to downstream turbines, which is related to the secondary wake steering effect. [PERSON] et al. (2018) discovered that by using a cooperative yaw control strategy, the total output power of five aligned turbines can be increased by 17.5 percent. [PERSON] et al. (2018) used high-fidelity simulations to investigate the effects of the yaw and tilt angles of an upstream turbine on the downstream turbine without changing the position of the upstream turbine. [PERSON] et al. (2019) suggested that when the spacing between two turbines is 5D, the total power output of two turbines will not continuously increase with the increasing of yaw angle of the upstream turbine, and the optimal yaw angle is 30\({}^{\circ}\). Based on the above research, we know that the wake of upstream turbines would strongly effect downstream turbines, resulting in the deflected velocity deficit, counter-rotating vortices, etc. Hence, it is needed to adopt appropriate yaw control strategies to improve the performance of wind farms. However, most previous research does not comprehensively consider the joint action of the spacing between two turbines and the yaw angle of the upstream turbine. It is conceivable that when the yaw control is adopted for the upstream turbine, the wake of the upstream turbine will be correspondingly deflected. It is necessary to investigate whether yaw control strategies based on fixed spacing are still effective or obvious when the spacing between two turbines varies. In this paper, the combined influences of yaw angle and turbine spacing will be fully analyzed by comparing the output powers and wake effects of two turbines in different yaw angles and longitudinal spacings.
## 3 Results and Discussion
### Synthesis and Characterization of CDs  
The hydrothermal/solvothermal synthesis of N-doped fluorescent CDs was prepared in a Teflon-lined autoclave batch reactor by a one-step synthesis procedure. Figure 3 displays the study of the effect of time on the synthesis of pristine CDs from the CPKS precursor without any dopant viewed (a) under normal light and (b) under UV-light. Figure 3c displayed (i) N-doped CDs with L-phenylalanine (CDs-L-Ph) and (ii) N-doped CDs using ethylenediamine (CDs-EDA) under normal light and Figure 3d(i) N-doped CDs with L-phenylalanine (CDs-L-Ph) and 3d(ii) N-doped CDs using ethylenediamine (CDs-EDA) viewed under UV-light showing fluorescence properties. The results show that subjecting CPKS to hydrothermal/solvothermal synthesis caused the material to undergo pyrolysis, nucleation, condensation, polymerization carbonization, and surface functionalization [1; 22; 46]. The aforementioned synthetic route or process is the approach for the fabrication of CDs, which changed the CPKS and resulted in photoluminescent crystalline CDs obtained in this research work [1; 46; 48]. The produced CDs emit a blue-violet colour at a wavelength between 430 and 450 nm when excited at a wavelength range of 350-400 nm in an alkaline medium, as shown in Figure 4a,b.
## 6 Conclusions  
The read threshold voltages of nonvolatile NAND flash memories depend on various factors such as the number of program/erase cycles, data retention times, and read disturb. Based on measured flash data, fixed predefined read thresholds lead to high bit error rates.  
In this work, we proposed two methods for adapting the read thresholds based on the number of errors observed in the codeword of an error correction code. The total number of errors in the codeword as well as the numbers of 1-to-0 and 0-to-1 errors are used as statistical features. These features were investigated utilizing the mutual information between the optimal read voltage and the measured error values. The total number of errors provides information about the distance to the optimal threshold and the asymmetry of the errors provides information about the direction. The total number of errors enables a prediction of the voltage shift for the initial calibration of the read thresholds. The second approach is a gradual channel estimation to cope with threshold calibration errors and voltage shifts over different pages of the same block. This approach is based on the asymmetric error distribution. Numerical results based on flash measurements demonstrate that both methods can significantly reduce the BER of NAND flash memories.  
In future work, the predictions of the voltage offsets for larger distances between pages should be considered. The proposed tracking method assumes sequential reads of pages. This simple adaption method is only suitable for pages nearby. Random access to pages from the same block would still require frequent calibration steps in end-of-life scenarios. Moreover, the impact of calibration errors on soft-input decoding algorithms requires more investigations [15; 22; 29]. Such soft-input decoding approaches typically assume quantization intervals that maximize the mutual information between the input and output of flash memory, which requires an accurate voltage adaptation.  
Figure 14: Error statistic on reference \(\tau_{7}\) of all pages of 27 Blocks with 55 h bake 3000 P/E.  
**Author Contributions:** The research for this article was exclusively undertaken by J.-P.T., D.N.B., J.F. and J.L.; conceptualization and investigation, J.-P.T., D.N.B. and J.F.; software and validation, J.-P.T. and D.N.B.; measurements, J.L.; writing--review and editing, J.-P.T., D.N.B., J.F. and J.L.; writing--original draft preparation, J.-P.T., D.N.B. and J.F.; supervision, project administration, and funding acquisition J.F. All authors have read and agreed to the published version of the manuscript.  
**Funding:** The German Federal Ministry of Research and Education (BMBF) supported the research for this article (16 ES1045) as part of the PENTA project 17013 XSR-FMC.  
**Acknowledgments:** The authors would like to thank Hyperstone GmbH, Konstanz, for supporting the research for this article.  
**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analysis, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
## 6 Revisiting the Failed Cases with \(\Delta_{C}\)  
The summary of Section 5.4 is essentially threefold. Firstly, the noise blowing-up strategy performs very well and with a negligible timing overhead in the target scenario for all five relevant attacks except AdvGAN, and in the untargeted scenario for all four white-box attacks but not for the three black-box attacks. Secondly, the poor performances of the strategy for AdvGAN (target scenario and untargeted scenario), EA (untargeted scenario), and SimBA (untargeted scenario) are essentially due to too low requirements put on these attacks during Phase 1 (Step 3 of Scheme (11), hence ahead of the noise blowing-up process). Thirdly, although between 74% and 83% of the pixels are modified on average, the adversarial images remain visually very close to their corresponding clean images, and actually and surprisingly the attacks themselves tend to reduce the differences introduced by the interpolation functions.  
We revisit these failed cases and make use of the Delta function \(\Delta_{C}\) introduced in Section 3.2 for this purpose. Indeed, we identified the origin of the encountered issues as essentially due to the too low distance between the label values of the dominating category and its closest competitors, hence due to a very small value of \(\Delta_{C}\) for the considered images and CNNs.  
Given \(\mathcal{A}_{a}^{\text{hr}}\) and \(\mathcal{A}_{a}\) (Step 1), and \(c_{a}\) (Step 2), we study in this Subsection how setting the increase of the values of \(\Delta_{C}\) as a requirement in Step 3 of Scheme (11) impacts the success rate of the noise blowing-up strategy for the failed cases. Note that putting additional requirements on \(\Delta_{C}\) may lead to lesser adversarial images at the end of Phase 1 as \(\Delta_{C}\) increases.  
We limit this study to \(atk=\text{EA}\) (untargeted scenario) and \(atk=\text{AdvGAN}\) (untargeted and target scenario). We regrettably exclude SimBA since we do not have access to its code.
# Customer-Oriented Quality of Service Management Method for the Future Intent-Based Networking
## 3 A Description of the Proposed Customer-Oriented Quality of Service Management Method for IBN
### Flow Routing Techniques with Load Balancing for Future IBN
In traditional networks, servicing occurs according to the order in which packets came (Figure 17). This option does not take into account the desirable customer ratings of the service level. It is proposed to sort by the following principle: the fastest will serve the highest rated packets and the shortest time. This time is different for each service type. It is proposed to mark the packets with an additional field for the transferring time. The best place to implement this field is to replace the TTL (Time To Live) field. The general idea remains the same (the packet can exist in the network for a limited period of time, the exhaustion of which triggers the rejection of the packet). However, for our method, it will give an additional ability to provide an appropriate order for service. Each router in the process of sending will deduct from the given field time spent on its maintenance. In order to combine different types of services, it is suggested that this time will be calculated in percentage equivalents. In this case, the services of the relevant assessment will have the appropriate priority of the service. From the usual sorting, this method differs by the ability of sorting not by type of service, but by an appropriate assessment and introduction of additional ability to manage traffic according to the time remaining for the packet's existence. The last option allows us to save packets that have little time to send, placing them in the queue in first place. The proposed algorithm for sorting packets is shown in Figure 18.  
In this case, if we service a packet that has a minimal time to send faster than the packet, which has enough time, for the second, quality will not significantly deteriorate. However, in this case, we can avoid the rejection of the first packet. Additionally, the waiting time for this packet (with a QoE rating of 5 and a minimum sending time) for filling the queue will be less than if we served packets in this order without sorting. In the last version, this packet is rejected. This service algorithm can be improved on IBN networks. Since this network can maintain statistics for each session, in the process of sorting, one can take into account one more factor--the number of packet rejections of a particular session. Each type of service has the meaning of the normal amount of possible discarded packets. Therefore, in case we have two identical packets of different sessions with the same small time, they will be served in the correct order--initially the packet, the number of discounts for which  
Figure 17: The traditional sorting packets method. session is greater, then another. This, in turn, will further improve the quality of service sessions on the network.
## 3 System Model
### System Description
However, the primary mechanisms used to control beamwidth, such as amplitude tapering, phase shifting, and steering, are generally designed to maintain a relatively constant input impedance across the operating frequency range. The authors of [41] investigated the \(\mathcal{S}\)-parameters in a few common antenna configurations. The authors of [42] investigated the power loss according to the beamwidth and they observed that the power loss increases as the beamwidth narrows. Moreover, in order to narrow the beamwidth, the number of phase shifters needs to be increased, which may deteriorate the impedance matching due to the increased complexity and coupling in the phase shifters.
## 2 Materials and Methods
### Preliminary Concepts and Simulation Configuration
#### 2.3.3 Scheduler
The scheduler is programed to give priority to the discharge of the data over the acquisition of new data when the amount of data stored on-board exceeds a certain limit. On the other hand, when the memory is below certain level (20% of the total storage maximum capacity) data acquisition has priority over the download of data.