esa-sceva/satcom-chunk-collection huggingface dataset:
# Comparison of L1 and L5 Bands GNSS Signals Acquisition
## 4 Application to GPS and Galileo Signals
### Comparison of GPS L1 C/A and L5 Signals Acquisition
#### 4.2.4 Validation  
To validate the previous developments, Matlab simulations have been performed for several sensitivities. GPS L1 C/A and L5 signals have been simulated with a random Doppler frequency within the search space and a random code delay, and acquired following the serial implementations of Section 2. This has been repeated 100 times, and the average of the measurements has been extracted.  
Figure 13 illustrates this for a sensitivity of \(-145\) dBm without assistance, where the ratio measured is relatively constant (the fluctuations are due to the fact that the detection may happen on a bin around the exact one). Then, Table 13 shows the theoretical and measured number of frequency bins and the ratio between L5 and L1. It can be seen that the number of frequency bins searched until detection is around half the total number of frequency bins, as expected. More importantly, it is seen that the measured ratio of the number of frequency bins searched matches the theoretical one, which validates the previous developments.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Parallel without Assistance**} & \multicolumn{3}{c}{**Serial with Assistance**} \\ \cline{2-9}
**Sensitivity** & \multicolumn{2}{c}{**Non-Coherent**} & \multicolumn{2}{c}{**Coherent Only**} & \multicolumn{2}{c}{**Non-Coherent**} & \multicolumn{2}{c}{**Coherent Only**} \\ \cline{2-9}  & **Average** & **Worst** & **Average** & **Worst** & **Average** & **Worst** & **Average** & **Worst** \\ \hline \(-140\) dBm & 63.1 & 81.9 & 23.0 & 46.2 & 3.2 & 4.1 & 0.8 & 1.5 \\ \(-145\) dBm & 73.2 & 83.3 & 91.8 & 140.4 & 3.7 & 4.7 & 3.0 & 5.3 \\ \(-150\) dBm & 79.1 & 80.1 & 189.6 & 242.3 & 4.5 & 4.6 & 7.0 & 8.9 \\ \(-155\) dBm & 76.8 & 76.2 & 264.4 & 289.9 & 4.4 & 4.4 & 10.2 & 11.2 \\ \(-160\) dBm & 74.2 & 73.7 & 303.9 & 313.5 & 4.3 & 4.3 & 11.7 & 12.2 \\ \hline \(-140\) dBm & 63.1 & 81.9 & 23.1 & 46.2 & 4.1 & 6.5 & 1.0 & 2.2 \\ \(-145\) dBm & 72.1 & 81.2 & 91.1 & 134.8 & 6.6 & 10.5 & 5.3 & 11.6 \\ \(-150\) dBm & 73.2 & 68.2 & 163.2 & 164.3 & 17.0 & 26.5 & 19.6 & 27.5 \\ \(-155\) dBm & 58.5 & 52.0 & 113.9 & 65.6 & 37.0 & 44.0 & 28.3 & 22.1 \\ \(-160\) dBm & 48.4 & 46.9 & 32.8 & 16.6 & 46.8 & 47.6 & 14.2 & 8.6 \\ \hline \hline \end{tabular}
\end{table}
Table 12: Final ratio of complexity (product of processing time ratio, memory ratio and frequency bins ratio) between the L5 and L1 C/A signals obtained as the product of Tables 10 and 11. Top rows do not consider the input memory, while bottom rows consider the input memory.  
Figure 13: Number of frequency bins browsed (**top**) and ratio (**bottom**) of this over 100 simulations, for a sensitivity of \(-145\) dBm without assistance.
## 2 Materials and Methods
### Methods
#### 2.2.1 PS-InSAR Displacements
The chosen area, indeed, does not show any kind of landslide risk according to the thematic geomorphological data [63] on the unstable areas of the Hydrogeological Plan (Piano per l'Assetto Idrogeologicom (PAI)). Dam displacements are evaluated by averaging the displacements of the selected PS points. As the direction of the retrieved displacement is only along the Line of Sight (LOS) of the sensor of the master image, the total horizontal displacement component orthogonal to the dam (\(D_{\text{TOT}}\)) needs to be calculated [53; 64] (a full list of the symbols used in the manuscript is listed in Appendix A, Table A2). Descending and ascending tracks overfly the study area on different dates; thus, it is required to interpolate the time displacements obtained using the descending tracks at the acquisition dates of the ascending tracks (as in the present case, and vice versa). Interpolated displacements then have to be composed [65; 66] with those obtained by processing the other track (the descending track in this research) to obtain \(D_{\text{TOT}}\).
# Risk Assessment of Soil Heavy Metals in the Jiahe River Basin of Yantai City, China
###### Abstract  
The issues related to soil environmental contamination caused by heavy metals have garnered increasing attention. In particular, the soil pollution risk in the eastern coastal regions of China has attracted widespread concern. This study surveyed heavy metals in the soils near the Jiahe River Basin of Yantai City in Shandong Province, China. A total of 213 soils were sampled and analyzed for 12 items: Cr, Hg, As, Pb, Cd, Cu, Ni, Zn, Co, V, Mn, and pH. The 11 heavy metals were evaluated using the national standard GB15618-2018, with three risk levels of background, screening, and intervention, and using pollution indices, including the contamination factor (C\({}_{\text{f}}\)), ecological risk factor (Er), enrichment factor (EF), and index of geo-accumulation (I\({}_{\text{geo}}\)), with different respective risk levels. The results indicate a strong consistency between the evaluations both for the index I\({}_{\text{geo}}\) and for GB15618-2018 on five metals (i.e., Cr, Hg, As, Pb, and Cd). Therefore, the index I\({}_{\text{geo}}\) may serve as a supplementary indicator for assessing the pollution risks of heavy metals in agricultural soils regarding samples of Cu, Ni, and Zn that exceed the screening values in GB15618-2018, as well as for Co, V, and Mn, which have not yet been established in GB15618-2018. According to the three-level classification of risk in GB15618-2018, the seven commonly used levels of the index I\({}_{\text{geo}}\) are also incorporated into the three levels of background, screening, and intervention. The overall pollution risk of 11 heavy metals in the soils of the Jiahe River Basin of Yantai City belongs to the background level. Specifically, Hg and Pb in the total area are classified at the background level. Manganese, V, Co, Zn, Ni, and Cr are recognized at the screening level sporadically, while Cu, As, and Cd are found at the screening level in small areas. No areas within the region are classified at the intervention level.  
keywords: heavy metals; soil; geo-accumulation index; pollution indices; GB15618-2018 +
Footnote †: journal: Applied sciences
## 3 Results and Discussion: Experimental Tests
### Ultrasonic Pulse Velocity (UPV)  
The UPV results shown in Figure 4 reflected the same trends as the mechanical properties. This aspect is the first indicator of a relationship of statistical dependence between this NDT measure and all the mechanical properties.  
The addition of fine RA led to a decrease in the UPV, due to the lower density and higher porosity of SCC after the addition of that aggregate [42], although values corresponding to a high-strength concrete were obtained in the mixes with 0% fine RA in spite of the 100% coarse RA of all the mixes. In a similar way to the mechanical properties, the UPV was higher in the mixes made with limestone powder, due to the high quality of the cementitious matrix [48], while the smallest values were obtained in the mixes made with RA power, because of the further porosity increase and density reduction it caused [50]. In fact, the use of RA powder in an SCC with 100% fine RA led to a UPV value lower than 3 km/s, corresponding to a low-strength concrete [16]. An aspect that the results of the mechanical properties such as compressive strength all confirmed (Figure 3).
## 2 Materials and Methods
### Flux Data Acquisition and Processing  
Each flux tower site has two systems including an EC and an automatic weather station (AWS) system, to obtain the energy fluxes and meteorological data. A three-dimensional sonic anemometer (CSAT3, Campbell Scientific, Logan, UT, USA) and a Li7500A open path CO\({}_{2}\)/H\({}_{2}\)O gas analyzer (LI-COR Inc., NE, USA) form an EC system to measure ecosystem scale CO\({}_{2}\) and H\({}_{2}\)O fluxes. The sampling rate was set to 10 Hz. Before releasing data to the public, the 10 Hz data was processed into a half-hour flux dataset by the Edire post-processing software (University of Edinburgh, Edinburgh, UK). The spike detection, lag correction of H\({}_{2}\)O/CO\({}_{2}\), sonic virtual temperature correction, coordinate rotation, Webb-Pearman-Leuning correction (WPL) [35], and frequency response correction were included in the procedures. In addition, sensor-faults, rain, and other bad weather can easily cause data loss or low quality. Therefore, data with poor quality was checked and excluded from the half-hour data [36]. The AWS system measures the relevant weather conditions including air temperature (Ta) (\({}^{\circ}\)C), precipitation (mm), etc. [37]. The data of the AWS system were recorded every ten minutes.  
In this study, three-year flux data and meteorological data of these typical sites were obtained from the Environmental and Ecological Science Data Center of West China ([[http://westdc.westgis.ac.cn](http://westdc.westgis.ac.cn)]([http://westdc.westgis.ac.cn](http://westdc.westgis.ac.cn))). Then, preprocessing such as outlier elimination was carried out. Gap-filling by a standardized algorithm and flux partitioning by the nighttime-based method were carried out with the R package by the Max Planck Institute for Biogeochemistry ([[https://www.bgc-jena.mpg.de/bgi/index.php/Services/REddyProWeb](https://www.bgc-jena.mpg.de/bgi/index.php/Services/REddyProWeb)]([https://www.bgc-jena.mpg.de/bgi/index.php/Services/REddyProWeb](https://www.bgc-jena.mpg.de/bgi/index.php/Services/REddyProWeb))). Flux partition was used to partition NEE into the GPP and ecosystem respiration (\(R_{c}\)). In particular, the latent heat flux and carbon dioxide flux data were missing from 1 st May 2016 to 23 rd August 2016 because of a malfunction of the Li7500 at the S_Sdq site and we gap-filled this part with multi-year mean imputation. Finally, we integrated these half-hour data into the daily time scale and then got the average of each eight-day period to compare with the BESS, MODIS, and GOSIF products.
###### Abstract  
Fifth-Generation (5G) cellular networks extensively utilize subscriber identifiers throughout the protocol stack, thereby linking subscribers to their activities on the network. With the inherent use of linked identifiers comes the potential capability to track subscribers' location and behavior, which poses critical challenges for user identity protections and privacy in sensitive applications like military or healthcare operating over public 5G infrastructure. The reliance on such personal identifiers threatens a user's right to privacy and brings to light the importance of proper mechanisms to mitigate these risks for current and future cellular network technologies. In this paper, we explore the 5G specifications to understand the most important list of identifiers and their use across Virtual Network Functions (VNF), and points of exposure within the Core Network (CN). We also examine the existing literature regarding identity protections and efforts to mitigate privacy concerns targeted in the CN. Findings include the need for a trust relationship between users and their network providers to protect and safeguard their identity. While 5G technology has greater user identity protections compared to previous cellular generations, our analysis shows that several areas of concern remain, particularly in the exchange of subscriber metadata. This work also finds that new technologies adopted in 5G networks add further complexity to maintaining a strict posture for safeguarding user identity and privacy protections. This paper also reviews the scientific community's proposed enhancements for future 6G networks' user identity and privacy protections, with a focus on emerging Artificial Intelligence (AI) and Machine Learning (ML) applications. The ethical implications of private or anonymous communications are also carefully weighed and examined to understand the multifaceted nature of this topic. Our work is concluded by proposing important further research to reduce the prevalence and reliance on personal identifiers such as the SUPI (Subscription Permanent Identifier) within 5G Core operations to help better protect user identity. We also propose replacing the widespread use of the SUPI between VNFs with ephemeral identifiers, building upon efforts by 3 GPP aiming for 5G to protect the SUPI from eavesdroppers.  
privacy; 5G; core network; supi; virtual network functions; service-based architecture; personal identifiers; anonymity; responsible privacy protection
###### Abstract  
Satellite laser communication is a promising technology for the next-generation communication system. Its communication performance is subject to the APT beam-pointing accuracy. One of the most important problems is reducing the coaxiality error before the APT starts working. However, the coaxiality error is difficult to correct effectively owing to the lack of empirical guidance based on qualitative analysis. We study the inducement that will generate coaxiality errors. The mathematical model of the influence of the CCR dihedral angle error and planeness error on the spot centroid measurement are built, and an analysis is performed. The model of the beam-pointing error induced by the APT element's assembly error is built, and the pointing error change rule is explored. Furthermore, the coaxiality performance simulation is performed in the presence of a CCR geometrical error while considering the assembly error. The results show that the coaxiality error has a nonlinear characteristic. The CCR planeness error has a greater influence on coaxiality deviation than that of dihedral angle error under certain conditions. This research is relevant to the design and test work of the APT system.  
space laser communication; coaxiality; cube corner retro-reflector; assembly error; beam-pointing accuracy +
Footnote †: journal: _Photonics_
# Three-Level Hybrid Envelope Tracking Supply Modulator with High-Bandwidth Wide-Output-Swing
## 5 Conclusions  
A hybrid envelope tracking supply modulator consisting of a class-AB linear amplifier, a three-level switching regulator, and a high-speed hysteresis control loop was presented in this paper. The proposed super source follower enables the linear amplifier to have a low output impedance at a very high frequency. Meanwhile, the hysteresis control method improves the loop response speed and the bandwidth of the switching regulator. The simulation results show that the modulator can track the 100 MHz envelope signal well with 85% peak efficiency. In addition, the modulator has a maximum output power of 1.5 W at the supply voltage of 5 V.  
Conceptualization, Y.L.; funding acquisition, Y.L. and X.Q.; methodology, K.Y., Y.L., C.C. and X.C.; project administration, X.Q. and B.X.; resources, X.Q.; software, C.C., B.X. and M.H.; supervision, Y.L., X.C. and B.X.; validation, X.C. and M.H.; writing--original draft, K.Y.; writing--review and editing, C.C. All authors have read and agreed to the published version of the manuscript.  
This research is supported by the National Natural Science Foundation of China under the grant No. 61971414 and Henan Province Key R&D and Promotion Project (Science and Technology Research) No. 212102210027 and Zhengzhou Zhongke Institute of Integrated Circuit and System Application Research Dean Fund No. ZK2005 BN003.  
Not applicable.  
The authors declare no conflict of interest.  
Figure 15: Simulation curve of output power and efficiency versus load resistance.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Reference** & [3] & [6] & [11] & [5] & [12] & [22] & **This Work** \\ \hline CMOS Technology & 180 nm & 180 nm & 250 nm & 180 nm & 180 nm & 65 nm & 180 nm \\ Supply (V) & 3.6 & 4.7 & 5 & 3.6 & 5 & 2.4 & 5 \\  & LTE-A & LTE & 5G NR & LTE & 10 MHz & LTE & 5G NR \\  & 40 MHz & 10 MHz & 40 MHz & 10 MHz & 80 MHz & 100 MHz \\ PAPR (dB) & NA & 7.5 & 12 & 7.24 & 6.95 & 7.84 & 7.5 \\ Output voltage (V) & 0.3–3.3 & 1.1–3 & 0.5–4 & 1.1–3.4 & 0.5–4.5 & NA & 0.3–4.6 \\ Output power (W) & 2.5 & 0.7 * & 0.3 * & 0.4 * & NA & 1 & 1.5 \\ Peak efficiency (\%) & 91 & 81.5 & 79.1 & 83 & 80 & 91 & 85 \\ \hline \hline \end{tabular}  
* ET PA output power.  
\end{table}
Table 3: Performance comparison with the prior arts.
# A Review of Methods and Applications for a Heart Rate Variability Analysis
## 3 Pressure Support Ventilation (PSV)
### Signal Decomposition Methods
#### 3.4.2 Discrete Wavelet Transform (DWT)  
Discrete wavelet transform (DWT) is a popular combined time-frequency analysis technique [42]. In this context, the \"wavelet\" denotes a non-symmetric, irregular, and small-duration waveform that possesses a zero mean, finite energy, and a real value of the Fourier transform [43]. Wavelets can be utilized to inspect the occurrences of typically hidden events within a signal. In the last few decades, the DWT method has emerged as an effective tool for analyzing nonstationary signals. In this method, the signals are subjected to a sequence of high- and low-pass filtering at every stage of disintegration to extract the detail and approximation coefficients, respectively. The detail coefficient does not participate in the following levels of decomposition. However, the estimation coefficient is involved in the subsequent disintegration level, leading to generating a fresh pair of detail and approximation coefficients. This procedure is sustained until the essential stage of signal breakdown is achieved. Therefore, the signal can be mathematically expressed, as revealed in Equation (2) [44]. The disintegration of HRVs utilizing the DWT method has been employed by researchers for various diagnostic applications like an automated diagnosis of diabetes [48] and sleep staging classification [49] in the last few decades.  
\[x(t)=x_{m_{0}}(t)+\sum_{m=-\infty}^{m_{0}}d_{m}(t) \tag{2}\]  
where \(x_{m0}(t)\) represents the signal, \(x_{m0}(t)\) represents the estimation coefficient at measure \(m_{0}\), and \(d_{m}(t)\) corresponds to the feature coefficient at scale \(m\).
# DTV Essential Hidden Area Decoder for DTV Broadcasting
## 2 The Conventional DEHA Analysis
### DTV Essential Hidden Area (DEHA)
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Location**} & \multicolumn{3}{c}{**Frame Memory Size**} \\ \cline{2-4}  & **Full HD** & **4K UHD** & **8K UHD** \\ \hline Active video in/output & \(1920\times 1080\) & \(3840\times 2160\) & \(7680\times 4320\) \\ DEHA & \(1920\times 8\) & \(3840\times 16\) & \(7680\times 32\) \\ CODEC and stream & \(1920\times 1088\) & \(3840\times 2176\) & \(7680\times 4352\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: DTV Essential Hidden Area (DEHA). Figure 1: DEHA encoding/decoding process and diverse encoding modes for DEHA. The investigation and development of methodologies to enhance the utilization of the DEHA are central objectives of this research, as its potential remains untapped in current practices. By optimizing the DEHA's usage, significant advancements can be made in channel efficiency and storage utilization, ultimately improving the overall performance and quality of DTV systems. Due to the interlaced field of frames, terrestrial HD content exhibits horizontal stripes at the bottom in Figure 2a when encoded with MPEG-2. However, there is an error in the bottom field. In the case of progressive internet HD content from YouTube, an H.264 encoder distorts the image by vertically bending a diagonal floral leaf due to the last line copy to DEHA in Figure 2b. It is crucial to handle the pixel data within the DEHA with care during the transformation from image space to the frequency domain to avoid potential degradation of the original video quality. Although the compressed data of the DEHA in Figure 2 forms only a small portion of the conventional video stream, altering the pixel data within the DEHA without careful consideration can have adverse effects on overall video quality. Further research is needed to gain a deeper understanding of the relationship between the DEHA and encoding algorithms, enabling the development of optimization techniques that enhance video quality while effectively utilizing the DEHA. Exploring the trade-offs between video quality, channel utilization, and storage efficiency will contribute to advancements in digital television systems.
###### Abstract  
In this paper, we propose an area-efficient short-time Fourier transform (STFT) processor that can perform time-frequency analysis of non-stationary signals in real time, which is essential for voice or radar-signal processing systems. STFT processors consist of a windowing module and a fast Fourier transform processor. The length of the window function is related to the time-frequency resolution, and the required window length varies depending on the application. In addition, the window function needs to overlap the input data samples to minimize the data loss in the window boundary, and overlap ratios of 25%, 50%, and 75% are generally used. Therefore, the STFT processor should ideally support a variable window length and overlap ratio and be implemented with an efficient hardware architecture for real-time time-frequency analysis. The proposed STFT processor is based on the radix-4 multi-path delay commutator (R4 MDC) pipeline architecture and supports a variable length of 16, 64, 256, and 1024 and overlap ratios of 25%, 50%, and 75%. Moreover, the proposed STFT processor can be implemented with very low complexity by having a relatively lower number of delay elements, which are the ones that increase complexity in the most STFT processors. The proposed STFT processor was designed using hardware description language (HDL) and synthesized to gate-level circuits using a standard cell library in a 65 nm CMOS process. The proposed STFT processor results in logic gates of 197,970, which is 63% less than that of the conventional radix-2 single-path delay feedback (R2 SDF) based STFT processor.  
short-time Fourier transform (STFT); fast Fourier transform (FFT); multi-path delay commutator (MDC); single-path delay feedback (SDF); non-stationary signal; time-frequency analysis +
Footnote †: journal: Applied Sciences
# PDF Malware Detection Based on Fuzzy Unordered Rule Induction Algorithm (FURIA)
## 1 Introduction
### Reason for the Selection of PDF Files  
The PDF format is one of the most widely used file types for sharing digital documents between different platforms and applications. Refs. [4; 5] contain a full description of the PDF standard. A few elements make PDFs one of the preferred file types for malware authors to disseminate dangerous content. (a) PDF is extensively utilized by people in both professional and social settings. Academic papers, technical reports, design documents, and electronic receipts are a few examples of typical instances; (b) PDF is independent of platforms and operating systems (OS). A standalone PDF reader or a modern web browser can be used to access a PDF file on a Windows PC, a Linux system, or a mobile device(with a PDF viewer plug-in); (c) it is a very versatile file format. In addition to text, PDF also allows other sorts of data, such as video files, interactive forms, links to other files, JavaScript, Flash, and unified resource locators (URLs). Additionally, different encoding and compression techniques can be utilized to reduce file size, conceal important material, or both; and (d) it is stealthy and sophisticated. In general, executable files are thought to be more dangerous than PDF files. Setting a policy to prohibit staff members from downloading executable files from the internet or including them in email attachments is a common security measure, but it is uncommon to do the same with PDF documents. The enormous ubiquity and adaptability of the PDF file format also provide attackers with several opportunities to spread malware through PDF documents.