esa-sceva/satcom-chunk-collection huggingface dataset:
# Audio Anti-Spoofing Based on Audio Feature Fusion
## 3 Experimental Setup and Details
### Experimental Details  
All model implementations in this paper were conducted using the PyTorch framework, explicitly utilizing the wav2 vec 2.0 XLS-R (0.3B) model. Raw audio was input into the wav2 vec 2.0 XLS-R model in approximately 4-second segments containing 64,600 sampling points, resulting in a feature representation size of (201, 1024). After embedding, the resulting feature size was (256, 512) and was input into an audio feature fusion module.  
A classification token (CLS) was added to the feature embedding to improve the classification accuracy. The CLS was then passed through a linear layer to obtain the necessary classification output.  
The model utilized four back-end classification layers, each containing a feature mixing module and n feature fusion modules. The value of n for each of the four layers was 3, 3, 9, and 3, respectively.  
During training, the model utilized the standard Adam optimizer with a fixed learning rate of 0.0001. The weighted cross-entropy loss was used to mitigate the impact of data imbalance between natural and synthetic speech in the training dataset, with a weight ratio of 9:1. The batch size was set at 16. All models were trained for 50 epochs on a single GeForce Tesla v100.
# Integration and Field Evaluation of an IoV System for Enhancing Road Safety
## 2 System Architecture
### On-the-Road Unit (ORU)  
The architecture of each ORU is presented in Figure 1. The magnetometers were embedded in very small printed circuit boards (PCBs) especially developed for the project, including low-profile electronic components and durable cable connectors that can be encapsulated in a protective material, installed on a road and withstand everyday use in such a harsh environment. The characteristics of the employed sensors, Melevis' MLX90393, are presented in Table 1[24]. As can be seen from the table, magnetometers of rather low power consumption, profile and cost were selected so that they can be replaced with a small cost if needed.  
Each ORU is connected to two (2) sensor strips placed vertically to the traffic flow of the road. Therefore, for two traffic lanes, as shown in Figure 1, every ORU collects data from eight (8) magnetoresistive sensors, four (4) for each lane, using the I\({}^{2}\)C communication protocol. A total of three (3) traffic lanes can be covered with the existing design, due to the I\({}^{2}\)C protocol's bus length limitations. Two of the four sensors of each lane, depicted in green in Figure 1, detect the passing vehicles first, while the other two, depicted in orange in Figure 1, detect each passing vehicle last. From the sequence in which these groups of sensors detect each passing vehicle and by measuring the time difference between two consecutive sensors excitation, critical parameters regarding the driver's behavior, such as the vehicle's speed and its direction can be calculated, given that the sensors strips are placed on the road with a fixed distance between them. In order to be detected by the ORU, the vehicle must be moving at a speed greater than 15 km/h. Four sensors are used per lane to cover every vehicle moving within the margins of the lane. The system can detect several vehicles at the same time.  
The developed ORU can communicate wirelessly via BLE and LoRa. The BLE is used for uniquely identifying each passing vehicle. This helps the system to collect vehicle-specific data and in turn provide personalized warnings to each driver, based on his/her  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Digital resolution & 16 bits \\ Dynamic range & 5–50 mT \\ Maximum sampling rate & 500 samples per second \\ Maximum current consumption (xy-axis acquisition) & 3 mA \\ Maximum current consumption (idle mode) & 5 \(\mu\)A \\ Packaging & QFN 3 mm \(\times\) 3 mm \\ Average unit purchase cost (single unit/5000 units) & 3 \(\upxi\)/1.30 \(\upxi\) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Technical characteristics of the MLX90393 magnetometers.  
behavior. Each ORU is also equipped with a LoRa communication module for sending data to the RSB.  
The developed ORU was based on Prisma Electronics' PrismaSenseTM universal data acquisition platform [25], adapted for data acquisition from MEMS magnetometers and communication via BLE and LoRa. More on the ORU, its features and the algorithms running on it are provided in [26].
## 3 Model Construction
### Time-Series Prediction Models
#### 3.2.2 GRU  
GRU has only two gates: the reset gate and the update gate [41]. Because the number of gates is reduced by one, its structure is correspondingly more simplified. The role of the update gate of GRU incorporates the forgetting gate and the input gate in LSTM, and the principle is similar to that of LSTM. Thus, the effects of the two models are not much different on several tasks. The GRU network architecture schematic is shown in Figure 6.  
The data are processed as shown in the following equations:  
\[z_{t}=\sigma(W_{z}\cdot[h_{t-1},x_{t}]) \tag{14}\]  
\[r_{t}=\sigma(W_{r}\cdot[h_{t-1},x_{t}]) \tag{15}\]  
\[\widetilde{h}_{t}=tanh(W\cdot[r_{t}*h_{t-1},x_{t}]) \tag{16}\]  
Figure 5: LSTM model structure.  
\[h_{t}=(1-z_{t})*h_{t-1}+z_{t}*\widetilde{h}_{t}, \tag{17}\]  
where \(x_{t}\) is the input, \(W_{S}\) is the weight parameter, \(\sigma(z)\) is an activation function, \(h_{t-1}\) is the output at the previous moment, and \(h_{t}\) is the output.
# Link and System-Level NOMA Simulator: The Reproducibility of Research
## 3 The NOMA System-Level Simulator
### Features of the System-Level Simulator  
We considered three scenarios to assess the features and potential of the proposed system-level NOMA simulator that includes the 7-cell scenario, 19-cell scenario, and 19-cell scenario with wrap around. These three scenarios are explained briefly, where users are randomly positioned in each cell for every system-level simulation. In our proposed NOMA system-level simulator, we consider a two-tier interference model, that is a user experiences interference from the 1 st tier and the 2 nd tier of cells.
## 6 Evaluation Results
The experimental values obtained using the lab testbed considered no localization errors, which are very unlikely in a real scenario. In this case, UDMSim will be an important tool, since the position and signal variations make it difficult to derive an accurate theoretical system model, especially for distances up to some hundreds of meters. For distances over 1 km, the simple theoretical model provides a good approximation since the travel time is the predominant factor. UDMSim can also benefit from other traces as input, including traces captured from real experiments, allowing offline replication of real world in simulation environment.
## 5 Conclusions  
In the present study, a tribological and thermal transport evaluation of environmentally friendly, pulsed laser ablated, Ag-based vegetable nanofluids was performed. Soybean, sunflower, and corn oils were used as liquid media to trigger bulk silver by laser irradiation. The incorporation of silver nanostructures within these natural lubricants showed overall positive results.  
It was observed that the irradiation time had significant effects on the nanofluids, and showed improvements in their tribological and heat-transfer characteristics. For instance, the limiting pressure of seizure improved compared to conventional lubricant, ranging from a 6% to 14% increase at 5 min irradiation, and up to a 24% increase at 10 min irradiation. This was attributed to the nanostructures displaying a rolling friction behavior, forming tribo-films, and tribosintering on the contact surfaces.  
Figure 4: Tribological performance of Ag-vegetable nanofluids at 5 and 10 min laser ablation times. (**a**) Sunflower oil, (**b**) Corn oil and (**c**) soybean oil.  
\begin{table}
\begin{tabular}{c c c c} \hline  & **Pure** & \multicolumn{2}{c}{**Ag**} \\  & **5 min** & \multicolumn{2}{c}{**10 min**} \\ \hline \multicolumn{2}{c}{COF-\(\mu\)} & & \\
**Soybean Oil** & 0.0385 \(\pm\) 0.0009 & 0.0365 \(\pm\) 0.0004 & 0.0345 \(\pm\) 0.0004 \\
**Corn Oil** & 0.0485 \(\pm\) 0.0006 & 0.0467 \(\pm\) 0.0004 & 0.0445 \(\pm\) 0.0003 \\
**Sunflower Oil** & 0.0437 \(\pm\) 0.0005 & 0.0402 \(\pm\) 0.0003 & 0.0372 \(\pm\) 0.0003 \\ \hline \end{tabular}
\end{table}
Table 3: COF performance at 5 and 10 min of Ag nanostructures by laser ablation.  
On the other hand, in general, all nanofluids showed a temperature-dependent behavior in thermal transport evaluations, also showing an interlayer interaction of silver with natural oils. Thermal conductivity improved in the range of 15% for 5 min ablation and up to 24% at 10 min ablation.  
The results showed the potential of this laser ablation technique and the application of natural oils as coolants or for metal-forming processes. Increased environmental awareness is the main driving force for the development novel technologies. Therefore, biodegradable fluids for use in environmentally sensitive areas have great potential to succeed in industrial applications.  
Conceptualization, J.T.-T.; Methodology, J.T.-T., K.A., and S.S.; Validation, J.T.-T., S.S., and S.S.K.; Formal analysis, J.T.-T.; Investigation, J.T.-T., S.S., and S.S.K.; Resources J.T.-T. and S.S.; Data curation, K.A., S.S.K., and M.I.M.P.; Project administration, J.T.-T.; Supervision, J.T.-T., S.S.; Writing-original draft, J.T.-T.; Writing-review & editing, J.T.-T., S.S., K.A., and S.S.K. All authors have read and agreed to the published version of the manuscript. This research received no external funding.  
Authors would like to acknowledge the support from Universidad de Monterrey. We express our gratitude to [PERSON] (CIMAV, Monterrey) for ICP-OES measurements and [PERSON] (CIMAV, Monterrey) for DLS measurements.  
The authors declare no conflict of interest.
###### Abstract  
The usage scenarios defined in the ITU-M2150-1 recommendation for IMT-2020 systems, including enhanced Mobile Broadband (eMBB), Ultra-reliable Low-latency Communication (URLLC), and massive Machine Type Communication (mMTC), allow the possibility of accessing different services through the set of Radio Interface Technologies (RITs), Long-term Evolution (LTE), and New Radio (NR), which are components of RIT. The potential of the low and medium frequency bands allocated by the Federal Communications Commission (FCC) for the fifth generation of mobile communications (5G) is described. In addition, in the Internet of Things (IoT) applications that will be covered by the case of use of the mMTC are framed. In this sense, a propagation channel measurement campaign was carried out at 850 MHz and 5.9 GHz in a covered corridor environment, located in an open space within the facilities of the Pedagogical and Technological University of Colombia campus. The measurements were carried out the time domain using a channel sounder based on a Universal Software Radio Peripheral (USRP) to obtain the received signal power levels over a range of separation distances between the transmitter and receiver from 2.00 m to 67.5 m. Then, a link budget was proposed to describe the path loss behavior as a function of these distances to obtain the parameters for the close-in free space reference distance (CI) and the floating intercept (FI) path loss prediction models. These parameters were estimated from the measurements made using the Minimum Mean Square Error (MMSE) approach. The estimated path loss exponent (PLE) values for both the CI and FI path loss models at 850 MHz and 3.5 GHz are in the range of 2.21 to 2.41, respectively. This shows that the multipath effect causes a lack of constructive interference to the received power signal for this type of outdoor corridor scenario. These results can be used in simulation tools to evaluate the path loss behavior and optimize the deployment of device and sensor network infrastructure to enable 5G-IoT connectivity in smart university campus scenarios.  
IoT; smart applications; sensor networks; device networks; LTE; NR; path loss models; path loss exponent; 5G; IMT-2020 +
Footnote †: journal: _Sensors_**2023**, 23, 9237. [[https://doi.org/10.3390/s23229237](https://doi.org/10.3390/s23229237)]([https://doi.org/10.3390/s23229237](https://doi.org/10.3390/s23229237))
## 3 Implementation of the Wireless Communication System Based on the Pulsed Coding Technique  
The optical pulsed UWB wireless communication system, performing the proposed data coding process, has been characterised by implementing the coding and decoding digital systems (see Figure 3) on an FPGA board (Xilinx VIRTEX-6 ML605, Xilinx Inc., San Jose, CA, USA) by a hardware description (VHDL, that is VHSIC Hardware Description Language where VHSIC means Very High Speed Integrated Circuits) of the functional/logic blocks previously described. The FPGA was used to: (i) supply the CLK\({}_{T}\) and \(S_{T}(t)\) signals at the input of the coding system that generates \(U_{T}(t)\); (ii) recover the CLK\({}_{R}\) and \(S_{R}(t)\) from the received \(U_{R}(t)\) through the decoding system. The resulting digital architecture is composed by a 2:1 multiplexer, a 1:2 demultiplexer, three D-type flip-flops and 22 logic gates (AND, OR, NOT). The corresponding circuitry can be implemented in standard Complementary Metal-Oxide Semiconductor (CMOS) technology as a full-custom solution with less than 150 transistors in a Si area smaller than 1 mm\({}^{2}\).  
The employed laser is a high-speed VCSEL-850 (Thorlabs Inc., Newton, NJ, USA) with 2.2 mA threshold current emitting at \(\lambda\) = 845 nm. This wavelength has been chosen considering the best light \"penetration window\" of human skin that ranges between 800 nm and 1300 nm [23].  
The photodiode is the Si high-speed FD5025 (Thorlabs Inc., Newton, NJ, USA) with 47 ps rise time and 49,000 \(\upmu\)m\({}^{2}\) sensitive area. All analogue circuits have been implemented on prototype PCB using high-bandwidth discrete off-the-shelf components. In particular, the VCSEL biasing and driving current circuitry has been implemented by employing the driver ADN2871 (Analog Devices Inc., Norwood, MA, USA) operating a voltage-to-current conversion. The output DC bias current was set to 2.25 mA (i.e., \(I_{\text{min}}\), see Figure 2) just about 2.5% above the VCSEL threshold current \(I_{\text{th}}\), while the peak value of the current pulses was regulated up to a maximum value of 4.5 mA (i.e., \(I_{\text{max}}\) = 2\(I_{\text{min}}\)). The photodiode biasing and signal conditioning circuitry has been implemented by using the ultra-low noise voltage-feedback operational amplifier OPA847 (Texas Instruments Inc., Dallas, TX, USA) configured as a transimpedance amplifier to convert the generated pulsed photocurrent into voltage pulses (i.e., a current-to-voltage conversion). This stage is combined with ADN2915 (Analog Devices Inc., Norwood, MA, USA) that includes a limiting amplifier and a signal level detector.
# Evolution of the Seismic Forecast System Implemented for the Vrancea Area (Romania)
NIEP's REWS system currently delivers real-time information to emergency authorities, while earthquake forecast data are graphically displayed on the AFROS website. In conclusion, based on extensive experimental data and long-term analysis, the NIEP's OEF system can provide a warning time of several hours before a major seismic event in the Vrancea region. This is achieved through real-time analysis of gas emissions (radon, CO\({}_{2}\)) and seismic activity based on the Gutenberg-Richter law. The system offers a viable cost-benefit ratio, accepted by funding agencies, and has been implemented using cost-effective and straightforward solutions in terms of equipment, maintenance, monitoring, and analysis software.
## 5 Conclusions  
In summary, we proposed a novel configuration which significantly enhanced the \(K^{2}\) of the two modes in ZnO/SiC structure. We used FEM to investigate the selection of ZnO normalized thickness, etching ratio, top electrodes, metallization ratio and bottom electrodes, and concluded that they all have large impacts on the performance of the SAW. The optimum \(K^{2}\) for the quasi-Rayleigh mode can exceed 12%, which increases near 12 times that of the conventional ZnO/SiC structure. Additionally, the \(K^{2}\) of the quasi-Sezawa shows twice the enhancement after optimization. This work has great reference value for more comprehensive research in the performance of ZnO/SiC structure and in realizing the unique characteristics of SAW devices based on modulating the etching ratio. The increased performance promises to meet the requirements of diverse fields, such as the fabrication of high frequency and wideband or remarkably miniaturized SAW filters and highly sensitive sensors.  
Conceptualization, H.X. and S.F.; methodology, H.X.; validation, H.X. and S.F.; data analysis, H.X., R.S., S.F. and J.S.; resources, F.Z., C.S. and F.P.; data curation, H.X.; writing--original draft preparation, H.X.; writing--review and editing, H.X., S.F., F.Z., C.S. and F.P.; visualization, H.X., R.S. and J.S.; supervision, H.X. and S.F.; project administration, H.X. and S.F.; funding acquisition, F.Z., C.S. and F.P. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the National Natural Science Foundation of China (Grant No. 52002205), the China Postdoctoral Science Foundation (Grant No. 2020M680557), the National Key Research and Development Program of China (Grant No. 2020 YFB0408900) and the Key Research and Development Program of Guangdong Province (Grant No. 2020B0101040002).  
Not applicable.  
The data presented in this study are available upon request from the corresponding author.  
The authors declare no conflict of interest.
# Blind Watermarking of Color Medical Images Using Hadamard Transform and Fractional-Order Moments
## 2 Related Work
In the field of medical image authentication, many authors suggested many watermarking systems to achieve data privacy and at the same time preserve image quality as possible to manage disease diagnostics. [PERSON] [43] proposed a watermarking method on medical images based on M-SVD utilizing DWT to embed binary watermarks into medical images. The author succeeds in scoring accurate quality measurements of the watermarked images utilizing the proposed M-SVD technique. [PERSON] and [PERSON] [44] introduced a location-based mobile system that provides a healthcare structure for users to find patients' location and disease diagnostic easily. [PERSON] and [PERSON] [45] proposed multiple zero-watermarking methods based on FrMGMs and scrambled to embed multiple watermarks into color medical images to present a high securing and robust watermarking system. [PERSON] et al. [46] introduced multiple blind watermarking schemes based on LWT and QR decomposition for medical images authentication. [PERSON] and [PERSON] [47] proposed a blind watermarking model to embed a binary watermark image into a color medical image utilizing the benefits of wavelet PCA, low-frequency sub-bands, and HSV wavelet coefficients. Based on this review of major revisions for most related methods, the proposed method's contributions are as follows:  
* Our method contributes to this evidence by using MFrLFMs. It is known for its stability and invariance to many geometric attacks, which keep robust capability over many attacks such as scaling, rotation, translation, etc. * In addition, MfrLFMs are not restricted to integer-order values, which give them a high ability to represent the finest details in the image rather than their rival's orthogonal polynomials of integer order. * The use of Walsh-Hadamard transform comes under generalized Fourier transforms, known as low-computations compilations. Hadamard transform is a perpendicular function, which is composed of (\(-1\) and \(+1\)) values only. Therefore, there is no data redundancy, which makes it widely used in many image processing analyses. FWHT is elastic to low-quality compression compared with other transformations such as traditional DCT and DWT, making it robust to most common image processing attacks. * The proposed method introduced a new combination method of these multi-channel fractional Legendre-Fourier moments (MfrLFMs) and Hadamard transformation in a holistic way to achieve the main target of the proposed method, which represents robustness to both geometric and image processing attacks. * The evaluation of our proposed method has been assessed for many common types of attacks and visual imperceptibility measurements.
## 3 Experiments and Analysis
### Quantitative Comparison  
Table 3 and Figure 9 present the experimental results, including BSF, SCRG, AUC, KS test results and ROC curves. In Table 3, the best-performing results are highlighted in _bold italics_, while the second-best results are underlined. Notably, the BSF and SCRG are reported as average values calculated across all detection results for the entire sequence. The performance of different methods is analyzed as shown below.
# A Novel Fractional Sine Chaotic Map and Its Application to Image Encryption and Watermarking
###### Abstract
presented the technique of encryption of images with chaotic fractional discrete time series in [29] and a novel technique was introduced in [30]. Tempered-type fractional derivatives in discrete time were proposed, and the encryption was discussed in [31]. Motivated by the investigations performed in the recent literature towards the field of image encryption [32; 33; 34; 35; 36; 37; 38], this article aims to contribute the following. 1. Construction of a novel fractional difference sine chaotic map with long-term chaotic response illustrated with bifurcation diagrams, Lyapunov exponents, and approximate entropy. 2. The application of the proposed discrete fractional sine chaotic map to image encryption of greyscale images is presented by generating a chaotic matrix. 3. The watermarking of the secret images at different levels is performed using transform methods. 4. For secure transmission of information stored in images, a genesis block is generated to diffuse the pixels of the images that can only be recovered by the recipient with the same genesis block (blockchain concept). The manuscripts planned with mathematical prerequisites in Section 2, and novel discrete fractional sine chaotic map construction and comparison are illustrated in Section 3. The scheme of encryption is presented in Section 4, and the analysis of results with supporting figures is provided in Section 5, with a conclusion in Section 6.
## 2 Miniaturization of the Microwave System
### Microwave Transmission System Miniaturization Design
#### 2.2.2 Conventional Length Waveguide Plus Miniaturized Ridged Waveguide
The effect of power transmission is close to the experimental result of the existing traditional microwave system. In this case, the size of the entire microwave system can be reduced to 316 mm, and the length from the power source to the bottom of the discharge chamber is only 388 mm. Although this solution has reduced the overall size of the microwave system, it is still difficult to fit into the accelerator's high-voltage spherical shell.