esa-sceva/satcom-chunk-collection huggingface dataset:
# Hybrid MU-MIMO Precoding Based on K-Means User Clustering
###### Abstract  
Multi-User (MU) Multiple-Input-Multiple-Output (MIMO) systems have been extensively investigated over the last few years from both theoretical and practical perspectives. The low complexity Linear Precoding (LP) schemes for MU-MIMO are already deployed in Long-Term Evolution (LTE) networks; however, they do not work well for users with strongly-correlated channels. Alternatives to those schemes, like Non-Linear Precoding (NLP), and hybrid precoding schemes were proposed in the standardization phase for the Third-Generation Partnership Project (3 GPP) 5G New Radio (NR). NLP schemes have better performance, but their complexity is prohibitively high. Hybrid schemes, which combine LP schemes to serve users with separable channels and NLP schemes for users with strongly-correlated channels, can help reduce the computational burden, while limiting the performance degradation. Finding the optimum set of users that can be co-scheduled through LP schemes could require an exhaustive search and, thus, may not be affordable for practical systems. The purpose of this paper is to present a new semi-orthogonal user selection algorithm based on the statistical K-means clustering and to assess its performance in MU-MIMO systems employing hybrid precoding schemes.  
5G NR (New Radio); Non-linear Precoding (NLP); hybrid precoding; Tomlinson-Harashima Precoding (THP); Regularized Zero Forcing (RZF); Block Diagonalization (BD); gaussian angular correlation; spatial compatibility; MU-MIMO; K-means clustering; user selection +
Footnote †: journal:  
_Article_
# Utilization of Phosphogypsum and Sediment in Subgrade Material for Pavement Construction
## 2 Materials and Methods
### Physical Analysis
#### 2.4.2 Consistency Limits  
The consistency limit was determined for all samples, reflecting the plasticity index of the material. This information is crucial for understanding the material's characteristics and assessing the feasibility of using phosphogypsum as a binder. Figure 1 illustrates the determination of both the material's yield strength and plasticity. Consistency limits, also known as Atterberg limits, are widely used in geotechnical engineering to characterize and classify fine-grained soils. These limits consist of three standardized tests designed to evaluate the plasticity and consistency of materials such as clay and silt. The Liquid Limit and Plastic Limit are critical components of this classification, providing insights into soil behavior in response to moisture variations. The liquid limit indicates the water content at  
\begin{table}
\begin{tabular}{l l l} \hline \hline
**Type of Testing** & **Number of Samples** & **Applied Standards** \\ \hline Geotechnical investigation and testing—Laboratory testing of soil—Part 4: Determination of particle size distribution & 1 & SRPS EN ISO 17892-4:2017 [27] \\ \hline Geotechnical investigation and testing—Laboratory testing of soil—Part 12: Determination of liquid and plastic limits & 9 & SRPS EN ISO 17892-12:2018 [34] \\ \hline Unbound and hydraulically bound mixtures—Part 2: Test methods for laboratory reference density and water content—Proctor compaction & 12 & SRPS EN 13286-2:2022 [35] \\ \hline Unbound and hydraulically bound mixtures—Part 50: Method for the manufacture of test specimens of hydraulically bound mixtures using Proctor equipment or vibrating table compaction & 12 & SRPS EN 13286-50:2012 [36] \\ \hline \hline \end{tabular}
\end{table}
Table 1: Type of physical analysis test, scope of test, and applied standards.  
which soil transitions from a liquid state to a plastic state, acquiring modest shear strength. It represents the minimum water content that maintains the soil in a liquid state or the maximum water content at which it remains in a plastic state.  
For this study, the liquid limit was determined using Casa grade's method. This method employs a firm rubber base with a British Standard [37] hardness ranging from 21 to 25. A brass cup, which descends from a specified height onto the rubber base, is operated via a handle-controlled cam mechanism. Adjustable screws allow for precise modification of the cup's drop height, initially set at 1 cm to commence the test. The plastic limit is defined as the lowest moisture content at which soil can undergo plastic deformation. In standardized testing, it signifies the minimum water content at which the soil begins to fragment when rolled into slender threads, typically around 3 mm in diameter. This parameter indicates the point at which the soil achieves minimal stiffness or strength. Understanding these limits is essential for evaluating the potential use of phosphogypsum as a binder in sediment remediation efforts.
## 3 Novel Framework for Advanced Synchrophasor Analysis in Modern Control Centres
### Spatiotemporal Synchrophasor Data Compression  
The idea of data compression is to transform the original input measurements into a small subset of coefficients with minimum information loss. The smaller this subset is compared to the size of the uncompressed signal, the higher is the compression rate. The applied signal transformation aims to eliminate all redundant information and can be inverted to reconstruct the original signals with a certain error (reconstruction error). In contrast to existing single-step approaches, the _spatiotemporal data compression module_ combines two compression stages to identify and eliminate redundant synchrophasor data in space (e.g., by PMU sensors with close proximity) and time (e.g., by low signal variations over long time spans)-see Figure 3. This enables high compression rates in presence of transient events and preserves low reconstruction errors. The compression rate \(r_{\mathrm{C}}\) is calculated according to (1) given the cardinality of the normalized input signal \(\mathbf{X}_  
For the spatial compression stage, different dimension reduction techniques can be used including principle component analysis (PCA), independent component analysis and non-negative matrix factorization. In case of the temporal compression, time-frequency transformations are suitable like discrete wavelet transform (DWT), discrete cosine transform or fast Fourier transform. Based on preliminary work [44], PCA and DWT are used as best combination to achieve low reconstruction errors and high compression rates. In the spatial compression stage, PCA is applied on the normalized measurement matrix, which creates a set of \"virtual\" PMU sensors depending on the number of chosen principle components. This ensures that only non-redundant information (highest signal variances) are captured by the first principle components. In this step, the temporal dimension (number of time steps) remains the same. In the second compression stage, DWT transforms each \"virtual\" sensor signal into the frequency domain. In case of multiple decomposition levels, this transform is applied recursively to generate the approximation and detailed coefficients. A compression is achieved by setting some detailed coefficients to zero depending on a predefined, global threshold value. PCA and DWT are both linear signal transform techniques. The PCA and the DWT parameters can be reused in the spatial and the temporal inverse processes to reconstruct the \"virtual\" sensor signals as well as the input measurement matrix-see Table 1. This procedure is applied on each PMU channel separately assuring optimal compression rates and reconstruction errors. A detailed description of the methodology as well as a comparison between the different compression techniques is given in [44].
## 2 Model and Methodology  
The BEV model for an L-7 vehicle and the methods developed for achieving estimations of the battery SoC variation and the residual driving range are presented within this section. Both battery SoC and residual range were estimated by relying upon previous battery power demand data acquired under real-world conditions. Since battery power demands can be considered as directly related to the vehicle's velocity along a driving mission, the availability of experimental data was viewed as an important opportunity to include driver behaviour, road and traffic conditions simultaneously in the analyses.
# Telecommunication Technologies for Smart Grid Projects with Focus on Smart Metering Applications
## 4 Smart Metering Applications--Smart Grid Projects
### Remarks--Technological Trends on Telecommunication Technologies
For example, wireless technologies (GSM, GPRS) are studied for grid monitoring and remote automatic grid reconfiguration in [126], whereas BB-PLC has been studied for the MV grid management and meter data gathering [127].
## Results and Discussion
### TMA Analysis  
#### 2.5.1 HS-SPME-GC-MS Method Validation  
HS-SPME, developed for the analysis of volatile compounds, has demonstrated a unique capability of incorporating extraction and concentration in one single step as well as compatibility with GC-MS [26; 27]. The validation of the analytical methodology for TMA analysis is presented in Table 3.  
Calibration curve linearity was calculated as suggested by [PERSON], 2009 [28]. The experimental Fisher value was compared to the critical theoretical Fisher value at 95%, with 12 and 4 freedom degrees (3.26). If the experimental dataset describes a proposed function calibration of the given form, then the condition (F\({}_{\text{theo}}\). \(>\) F\({}_{\text{exp}}\).) must be fulfilled. The best result was achieved for the presented 2 nd degree polynomial equation. The results obtained for the remaining evaluated parameters were in agreement with the reference values stipulated by the AOAC guidelines [29]. For the matrix effect, the reference is between 70 and 125%; the intermediate precision and repeatability references are below 15% RSD, and recovery is 80-115%.
## 1 Introduction
### Accompanying Development Model and Software Life-Cycle with Proper Software Structure
#### 1.7.1 Microservices  
A microservice is a single service built to accommodate an application feature. It handles discrete tasks within a microservices architecture. Each microservice communicates with other services through simple interfaces to solve business problems. The key benefits of the microservices are that they are:  
* Independently deployable;
* Loosely coupled;
* Organized around business capabilities;
* Owned by a small team.  
As can be easily seen, all of the problems identified in Section 1.3 of a typical CubeSat software are addressed by the nature of the microservice. The idea of using microservices architecture opens up the migration options for the initially monolithic software via the use of the \"strangler application\" design pattern. The process of such migration is called \"Strangling the monolith\". The industry of software development is rapidly booming in using such an approach, and there are numerous metrics and tools related to this topic [34].
Therefore, it is important to emphasize that studies to date have primarily examined only one specific set configuration (three sets of three maximum attempts) and one total ICA duration without direct comparisons [1,4,10]. This approach limits the ability to determine the optimal number of sets--and consequently, the total ICA duration--for maximizing PAPE effects assessed across several time points following the intervention of all ICA sets in highly trained athletes. In contrast, [PERSON] and [PERSON] [3] indicated that single sets of CA for stronger individuals promote superior neuromuscular adaptations than multiple sets of CA, a phenomenon particularly relevant to highly trained athletes. As highlighted by [PERSON] and [PERSON] [3] and [PERSON] et al. [5], these mechanisms may be linked to the increased phosphorylation of myosin light chains, enhanced motor unit recruitment, and athletes' greater tolerance to an induced loading [15]. This effect could similarly apply to ICA protocols. It is worth considering that the use of ICA may lead to different outcomes compared to traditional isotonic CA due to factors such as reduced muscle damage, decreased fatigue levels, or other differences in neuromuscular adaptations. These factors suggest that the results obtained from studies on isotonic CA may not necessarily be fully applicable to ICA. Therefore, it is important not to rely solely on the existing literature on isotonic CA but rather to conduct direct comparisons of the effectiveness of various series volumes (one set vs. three sets) and the total duration of ICA (9 s vs. 27 s) in order to better understand the adaptive mechanisms that may occur during ICA implementation. Consequently, this study aims to fill this gap by directly comparing the effects of different volumes of sets (one set vs. three sets) and total durations of ICA (9 s vs. 27 s) on CMJ performance in highly trained athletes, measured at multiple time points post-ICA, in comparison to a control condition (CTRL). We hypothesized that both protocols would increase CMJ performance at all measurement points (3, 6, and 9 min), with the greatest effect achieved at 6 min; this is typically when the peak response occurs [6]. Additionally, we expected the three-set protocol to produce a greater improvement in CMJ height compared to the one-set protocol.
# Biosorption of Heavy Metals by the Bacterial Exopolysaccharideaccharide FucoPol
## Materials and Methods
### Metal Biosorption Experiments  
To evaluate the ability of FucoPol for binding metals in aqueous systems, the method described by [PERSON] et al. [32] was performed, with some modifications. Equilibrium dialysis experiments were carried out by placing dialysis tubing (12-14 kDa MWCO membrane, ZelluTrans/Roth) containing the FucoPol solution (5 mL) in closed glass flasks with 200 mL of the appropriate metal solution. The flasks were placed in an orbital shaker (150 rpm) and kept at 21 \({}^{\circ}\)C, for 24 h. Experiments were performed in triplicates. Controls were performed using deionized water in the dialysis tubing instead of the FucoPol solution. Samples of the metal solution (2 mL) were taken before and after the incubation period and the metallic ions were quantified by Inductively Coupled Plasma--Atomic Emission Spectroscopy (ICP-AES) (Ultima, Horiba Jobin-Yvon, France, equipped with a 40.68 MHz RF generator, Czerny-Turner monochromator with 1.00 m (sequential) and autosampler AS500).
## 3 System Model and Problem Formulation
### Problem Formulation  
#### 3.2.1 User Clustering  
Before the joint user scheduling and hybrid beamforming design, it is necessary to group the active users within the coverage of the LEO satellite. Based on the CSI, the hierarchical clustering algorithm is adopted to group users [30]. As shown in Figures 4 and 5, the hierarchical clustering algorithm adopts the bottom-up method, where each user initially forms a group, and then according to the similarity measurement function, the user groups which meet the similarity threshold constraint are combined until the desired number of groups is formed.  
We adopt the similarity measurement function among multicast groups based on the _Ward_ connection method, i.e.,  
\[d(i,j)=\sqrt{\frac{2n_{i}n_{j}}{n_{i}+n_{j}}}dist(\mathbf{h}_{i}^{eq},\mathbf{h}_{j}^{eq}), \tag{15}\]  
where \(n_{i}\), \(n_{j}\) represent the number of users of the group \(i\) and the group \(j\), respectively, \(\mathbf{h}_{i}^{eq}\), \(\mathbf{h}_{j}^{eq}\) represent the equivalent CSI of the group \(i\) and the group \(j\), respectively, and \(dist(\mathbf{h}_{i}^{eq},\mathbf{h}_{j}^{eq})\) represents the Euclidean distance between the vector \(\mathbf{h}_{i}^{eq}\) and the vector \(\mathbf{h}_{i}^{eq}\), i.e.,  
\[dist(\mathbf{h}_{i}^{eq},\mathbf{h}_{j}^{eq})=\left\|\frac{\mathbf{h}_{i}^{eq}}{\left\| \mathbf{h}_{i}^{eq}\right\|}-\frac{\mathbf{h}_{j}^{eq}}{\left\|\mathbf{h}_{j}^{eq}\right\|}\right\| \tag{16}\]
# Key Roles of Plasmonics in Wireless THz Nanocommunications--A Survey
## 3 Wireless Nano Sensor Networks
As far as concerns in the biomedical applications domain, graphene based nanoantennas have been used for wireless communication between nanosensors, deployed inside and over the human body, resulting in many bio-nanosensing applications [72]. In-vivo wireless nanosensor networks (iWNSNs) at the THz band, is a characteristic application for providing fast and accurate disease diagnosis and treatment [73]. These networks, fully equipped with nanoscale components (e.g., nodes, routers, gateways, links and interfaces) as in regular networks, as seen in Figure 5, are operating inside the human body in real time, achieving precise and real time medical monitoring and medical implant communication. Apart from iWNSNs, graphene plasmons have also been used in biological sensing applications, monitoring the rotational and vibrational modes of DNA molecules and many large proteins in the THz and far-IR [74,75]. Moreover, as far as concerns imaging applications, and especially the THz band spectroscopy, nanosensors have been used for backscattering techniques for monitoring the dynamics of large biomolecules [76]. A THz biosensor communicating with the biological agents through a graphene plasmonic waveguide is described in [77]. In this sensor, SPPs in the waveguide must be launched by either an external near-field source or an antenna. In [78], another biosensor system has been proposed, where all the required elements (the sensor, frequency modulator,  
Figure 4: Energy harvesting is based on the piezoelectric effect seen in zinc oxide (ZnO) nanowires. and antenna for energy harvesting) are packaged in a single module [78]. This structure has been designed as a dual resonant antenna part of a GFET.
## 2 Materials and Methods  
A single-center pilot study was carried out on patients referred to the department from January to November 2022. All the study procedures were performed in accordance with the ethical standards of the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The protocol was approved by the Local Ethical Committee (Prot. n. 775/17, RIF.CE: 4687). This study was registered on the ISRCTN registry (ISRCTN80613224). An informed consent form was signed by each patient prior to their participation in this study.  
Patients undergoing the surgical extraction of a partially bony impacted mandibular third molar with class II or III and position B and C according to the Pell and Gregory classification were included in this study [25]. The inclusion criteria were normal healthy patients of both genders, with an age \(\geq\) 18 years, no smoking habits, the absence of pericornitis, and no allergy to anesthetic solutions. The exclusion criteria were patients who refused participation in the study, pregnant or lactating patients, patients who were sub jected to anti-inflammatory drugs or antibiotic therapy less than 2 weeks before the surgical intervention, patients with systemic disorders, and patients who did not complete the designed questionnaires in this study. The inclusion and exclusion criteria were established and based on including patients with the same level of difficulty of surgical extraction and excluding patients who have a systemic condition or had/have any history of drug intake (such as anti-inflammatory or antibiotic drugs) that may influence the healing process and, therefore, may influence the results.  
Patients fulfilling the inclusion criteria were randomly allocated to two groups: (1) the Test Group (TG) consisted of patients who were subjected to intraoral and extraoral PBM applications immediately after surgical extraction, and (2) the Control Group (CG) consisted of patients who were subjected to only the surgical intervention without PBM application. Opaque and sealed envelopes were prepared, in which \"with PBM\" or \"without PBM\" was written. After making a decision regarding the eligibility of the patient and obtaining consent, the allocation of the patient in a group was determined by a professional not involved in this study, who blindly selected the envelope for each patient.
###### Abstract  
This paper proposes a novel Deep Learning (DL)-based approach for classifying the radio-access technology (RAT) of wireless emitters. The approach improves computational efficiency and accuracy under harsh channel conditions with respect to existing approaches. Intelligent spectrum monitoring is a crucial enabler for emerging wireless access environments that supports sharing of (and dynamic access to) spectral resources between multiple RATs and user classes. Emitter classification enables monitoring the varying patterns of spectral occupancy across RATs, which is instrumental in optimizing spectral utilization and interference management and supporting efficient enforcement of access regulations. Existing emitter classification approaches successfully leverage convolutional neural networks (CNNs) to recognize RAT visual features in spectrograms and other time-frequency representations; however, the corresponding classification accuracy degrades severely under harsh propagation conditions, and the computational cost of CNNs may limit their adoption in resource-constrained network edge scenarios. In this work, we propose a novel emitter classification solution consisting of a Denoising Autoencoder (DAE), which feeds a CNN classifier with lower dimensionality, denoised representations of channel-corrupted spectrograms. We demonstrate--using a standard-compliant simulation of various RATs including LTE and four latest Wi-Fi standards--that in harsh channel conditions including non-line-of-sight, large scale fading, and mobility-induced Doppler shifts, our proposed solution outperforms a wide range of standalone CNNs and other machine learning models while requiring significantly less computational resources. The maximum achieved accuracy of the emitter classifier is 100%, and the average accuracy is 91% across all the propagation conditions.  
Deep Learning; Denoising Autoencoders; convolutional neural networks; classification; IEEE Wi-Fi protocols; LTE; spectrum management +
Footnote †: journal: _Sensors_
## 4 Results
### Cell Viability Assay  
The cell viability on the superficial silver nanoparticles of different sizes was measured by Alamar blue assay. As a control, the cells were also seeded on to the surface of untreated, polished titanium surfaces.  
After 14 days of culture, the cells seeded on surfaces covered by silver particles 60 and 96 nm in average diameter showed viability similar to the control surface. However, in the case of the surfaces covered with 149 and 368 nm average diameter silver particles, we observed monotonic reduction (Figure 8) of cell growth compared to the 60 nm particle surface. The viability of the cells grown on the 149 and the 368 nm particle surface was also reduced when compared to the 96 nm particle surface.  
Figure 8: The effect of the diameter of superficial silver nanoparticles on the viability of dental pulp stem cells (DPSCs). Cells were seeded on silver nanoparticle covered titanium discs and cultured for 14 days. Cell viability was measured by Alamar Blue assay. Values are expressed as sample means, and error bars represent the standard deviations (\(n=3\)). Statistically significant differences are indicated with asterisks (* \(p\) <0.01).  
Figure 7: SEM images with nanoparticles of appropriate average diameter (**A**): 60 nm; (**B**): 96 nm; (**C**): 149 nm; (**D**): 368 nm and cell growth on them.