esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Numerical Results and Discussion  
In this section we apply the proposed dynamic shadowing model to two practical and modern scenario scenarios of wireless systems. The first one refers to a dual-hop wireless system and the second one to a mobile station receiving signals from two base stations. There are also many practical scenarios that can be applied, such as interference, hand over, cooperative diversity, multiple antennas transmission and reception.  
The system under consideration is supposed to operate according the specified requirements, when the received \(SNR_{R}\) is greater than a threshold value \(SNR_{TH}\), \(SNR_{R}\geq SNR_{TH}\), or in linear scale \(\gamma_{R}\geq\gamma_{TH}\). The threshold value depends on the type of modulation and the type of the supported application. This requirement may be translated in terms of the transformed process \(X\) of (15), as:  
\[X\geq SNR_{TH}-(SNR_{T}-\overline{PL}). \tag{36}\]  
If we define the fade margin \(FM\) as:  
\[FM=SNR_{T}-\overline{PL} \tag{37}\]  
and we assume for simplicity that \(SNR_{TH}=0\) dB, by simply adding the threshold value to the propagation losses, then the requirement for operation is transformed to  
\[X\geq-FM. \tag{38}\]  
In order not to refer to specific equipment characteristics we present the results in relation to the fade margin. When the receiver is moving, assuming local stationarity over the characteristic area for shadowing, we present the results as a function of distance covered for a specific trajectory, assuming an initial fade margin value and referring to the specific large scale fading model used for the subsequent variation of the fade margin as the mobile moves.  
As stated also previously, to the authors' best knowledge there are no specific measurements in the literature to validate the proposed approach. The future experimental campaigns should be designed in order to capture the dynamic temporal variability of the large scale fading e.g., in a crowded local environment for various sites and for different frequency bands.
## 2 Relevant Work
RushNet first develops a network backbone on which high volume of low priority data is transmitted and high priority packets are then sent without the need to stop ongoing transmissions; capture effect is used for this purpose which is the property of a radio to be able to decode a stronger signal from one transmitter, even if other weaker signals are also available in the range. Thus, the radio capture effect enables the nodes in RushNet to send the low volume high priority data anytime. Although RushNet allows higher priority data to be transmitted even if the channel is busy, two separate transceivers are required by the protocol, which is its major drawback. The major research gap identified in the light of the above literature analysis is the lack of a MAC protocol which could offer a true preemptive priority mechanism for heterogeneous traffic in WSNs. Table 1 summarizes the pros and cons of the priority schemes reviewed in this paper.
# Analytical Framework of CP-Free Multiuser OFDM System for Coordinated Multi-Point at mmWave
## 4 Conclusions and Future Challenges  
In this study, the implementation of the CHT as well as BD channel precoding techniques in the CoMP-JT-transmission-method-based mmWave CP-free multiuser OFDM wireless communication system resulted in the reduction of multiuser interference. Moreover, subcarrier mapping for OOB reduction, IBO-aided HPA for PAPR reduction, and RA channel coding in particular for forward error correction has been introduced. Furthermore, the impact of the CoMP-JT-based transmission technique on SINR and ergodic achievable rate with the varying transmission power at mmWave is studied. In addition, ergodic achievable rates are also estimated with varying transmitting antenna height at a certain covered distance between two BSs.  
The numerical results show that in mmWave transmission, the received signal power in proportion to transmitted signal power is comparatively very low within the covered transmission distance. This is due to the fact that the path loss is generally very high in mmWave transmission system as it is known from the literature that shorter wavelengths are usually impaired with strong reflections, refractions, and scattering. Although the developed simulated system is robust in terms of PAPR and OOB reduction as well as BER improvement with reasonably acceptable power spectral density, there is scope to improve the system under massive MIMO channels, e.g., the deployment of an antenna array at the BS utilizing more than 100 antenna elements; such a system under a massive MIMO scheme can notably provide an enormous increase in throughput [39]. In the future, the developed simulated system can surely be integrated with mMIMO and a transmit antenna selection technique to make it even more robust considering its improved performance [40; 41].  
Conceptualization, J.J.S., S.R.S., S.E.U., R.R., and M.R.I.; methodology, J.J.S., S.R.S., and S.E.U., R.R., and M.R.I.; software, J.J.S., and S.E.U.; validation, J.J.S., S.E.U., M.A.H., and R.R.; formal analysis, J.J.S., S.R.S., S.E.U., and R.R.; investigation, J.J.S., S.R.S., and S.E.U.; resources, J.J.S., S.E.U., and R.R.; data curation, J.J.S., and S.E.U.; writing--original draft preparation, J.J.S., S.R.S., S.E.U., and R.R.; writing--review and editing, M.A.H., M.R.I., A.Z.K., and M.A.P.M.; supervision, S.E.U., R.R., M.R.I, and A.Z.K.; project administration, S.E.U., and R.R.; funding acquisition, R.R.; M.R.I., A.Z.K., and M.A.P.M. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not Applicable.  
The authors declare no conflict of interest.  
Figure 23: BER performance comparison between the proposed uncoded system with other multicarrier uncoded systems.
## 4 Experiments and Results
### Part B--Hot Gas Propulsion
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Temperature**} & **Impulse** & **Related** & **Percentage** & **Impulse** & **Related** & **Percentage** \\  & **(Poly)** & **Impulse** & **(Non/bar)** & **(Polynomial)** & **(Linear)** & **Impulse** & **Growth** \\  & **(Ns)** & **(Ns/bar)** & **(Polynomial)** & **(Ns)** & **(Ns/bar)** & **(Linear)** \\ \hline \hline \multicolumn{8}{c}{Tested values} \\ \hline
25 & 63.92 & 1.27836 & 0.00 & 63.31 & 1.26623 & 0  
which is fitted with a cold gas propulsion system. Adelis-SAMSON carries 468 gr of Krypton at 160 bar and 30 \({}^{\circ}\)C. This ensures a total impulse of \(>\)150 Ns [32]. In comparison, the hot gas propulsion system develops a total impulse of 172 Ns with nitrogen at 450 \({}^{\circ}\)C and 27 bar, heated from 25 \({}^{\circ}\)C and 20 bar. Despite the fact that direct comparisons are difficult, as the tank volume and pressure are different for both solutions, it can be noticed that the hot gas propulsion system offers a 14.6% increase in the total impulse, with same mass of propellant but at six times-lower propellant pressure.
# Graph Neural Networks for Routing Optimization: Challenges and Opportunities
## 1 Introduction
* This survey provides an up-to-date literature review of GNN techniques for routing, which were performed by a diverse group of experts in a wide range of application domains. * This survey presents an introduction to ML and GNN basics to help researchers who want to kick-start the relevant studies. * This survey classifies the most recent works in the past four years (i.e., 2018-2022) within the scope of three main categories, namely, supervised learning for network modeling, supervised learning for routing optimization, and reinforcement learning for routing optimization. * This survey analyzes the existing studies carefully, covering the proposed solution, GNN techniques involved, routing policy, and performance. * This survey proposes a set of research challenges and opportunities for future research. As applying GNNs to routing problems appeared only a few years ago, it is still a relatively new field, there are many research opportunities in this research topic. The remainder of this paper is organized as follows. Section 2 introduces the basic concepts of routing, machine learning and graph neural networks. Section 3 discusses relevant studies in the category of supervised learning for network modeling. Section 4 discusses relevant studies in the category of supervised learning for routing optimization. Section 5 discusses relevant studies in the reinforcement learning category of routing optimization. Section 6 presents the relevant academic resources, including open datasets and programming tools, which can be further employed by interested scholars. The challenges and opportunities for inspiring follow-up studies are summarized in Section 7. Finally, Section 8 concludes the paper. The abbreviations of the terminologies used in this survey are summarized in Table 2. \begin{table}
\begin{tabular}{l l} \hline \hline
**Abbreviation** & **Full Name** \\ \hline A2C & Advantage Actor Critic \\ AI & Artificial Intelligence \\ BGP & Border Gateway Protocol \\ CCN & Content-Centric Network \\ DDPG & Deep Deterministic Policy Gradient \\ DGATR [48] & Deep Graph Attention Network Routing \\ DGL & Deep Graph Library \\ DGRL [49] & Deep Graph Reinforcement Learning \\ DL & Deep Learning \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The abbreviations and the corresponding full names used in this survey.
## 2 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Reaction** & \multirow{2}{*}{\begin{tabular}{c} **DFT/** \\ **Basis Set** \\ \end{tabular} } & \multirow{2}{*}{**7H-1c**} & \multirow{2}{*}{**Salt 1c**} & \multirow{2}{*}{**\
\begin{tabular}{c} **Iminium** \\ **Salt 1c** \\ \end{tabular} } & \multirow{2}{*}{**Animal 1c**} & \multirow{2}{*}{**
\begin{tabular}{c} **Transition** \\ **State 1c** \\ \end{tabular} } & \multirow{2}{*}{**3c**} \\
**Solvent** & & & & & & & \\ \hline \multirow{3}{*}{**3c** (1R,2S)} & B3 LYP/ & 0 & 2.7 & 7.5 & 0 & 16.8 & \(-\)4.7 \\  & 6-31+G(d) & \(0\) & _6.7_ & _10.4_ & _10.4_ & _34.2_ & _10.6_ \\ \multirow{3}{*}{MeOH} & B3 LYP-D3/ & 0 & 1.9 & 5.5 & \(-\)7.2 & 11.6 & \(-\)14.7 \\  & 6-31+G(d) & \(0\) & _6.1_ & _8.8_ & _6.9_ & _26.3_ & _1.8_ \\ \hline \multirow{3}{*}{**3c** (1S,2S)} & B3 LYP/ & 0 & 3.1 & 7.5 & 0.9 & 19.4 & \(-\)4.4 \\  & 6-31+G(d) & \(0\) & _6.1_ & _10.4_ & _14.3_ & 35.9 & _10.9_ \\ \multirow{3}{*}{MeOH} & B3 LYP-D3/ & 0 & 3.1 & 5.5 & \(-\)7.6 & 10.7 & \(-\)14.5 \\  & 6-31+G(d) & \(0\) & _6.3_ & _8.8_ & _6.8_ & _27.0_ & _1.9_ \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The relative electronic (plain text) and Gibbs free (italics) energies (kcal/mol) of subsequent stages of the tandem Mannich—electrophilic amination reactions calculated by B3 LYP and B3 LYP-D3 methods. These results prompted us to investigate the structure of iminium zwitterion **1c** using quantum chemical calculations (B3 LYP/6-31+G(d)). As shown in Figure 2, the highest densities of the lowest unoccupied orbital (LUMO) can be found on the iminium carbon atom. However, the carboxylate group strongly affects the topicity of this atom favoring Re-face reactivity that results in formation of 1R,2S diastereoisomer **3c**. An extensive literature review has confirmed the proposed reasoning. Thus, 1-[(2-hydroxy-1-naphthyl)methyl]proline, obtained via Mannich-type condensation from \(\beta\)-naphthol, L-proline and formaldehyde, reacts with boron compounds with high diastereoselectivity [18]. Next, we examined the reaction path that results in formation of 2,2-diethyl-1,2-dihydro-[1,2,4]triazolo[4,3-\(a\)]quinolin-2-ium-4-carboxylate (**6**), i.e., Safirinium Q dye (Scheme 3). The results obtained clearly indicate that isoxazolo[3,4-\(b\)]quinolin-3(1\(H\))-one (**4**) is more reactive than 4,6-dimethylisoxazole[3,4-\(b\)]pyridin-3(1\(H\))-one (**1**) with respect to the tandem Mannich-electrophilic amination process. Hence, the calculated transition state energy barrier amounts to 14.3 or 16.2 kcal/mol in water and 14.4 or 16.7 kcal/mol in methanol, when estimated with B3 LYP-D3 and \(\omega\)B97X-Dand methods, respectively (Table 3). These values are ca. 4 kcal/mol lower than those estimated for the transition state **1a**. Analogous tendencies can be observed when comparing the estimated Gibbs free energies for products **3a** and **6**.
# A Critical Review of Flood Risk Management and the Selection of Suitable Measures
## 3 Risk-Based Flood Management
### Assorting Suitable Measures
#### 3.6.1. Suitable Measures at Catchment  
Catchment management can be an effective option with or without the support of other measures. Some land-use practices can increase the tendency of rapid and high peak runoff, especially if the soil surface is left bare for long periods of the year, or periods when heavy drainage is more likely [59; 65]. Not only land use, but also installing meteorological and hydrometric telemetric stations in the basin, is important for an effective flood forecast-warning system. It is important to record meteorological and hydrometric data in real-time [66]. In most cases, there is ample time to identify and notify the local authorities of an oncoming significant flood event [60].  
Agricultural activities play a significant role in the generation of total volume and peak flow. For example, livestock above certain densities can lead to soil compaction (which increases rapid surface runoff) and the loss of water to evapotranspiration is minimized by reducing biomass, thereby increasing the runoff [67]. The way the catchment's surface is controlled by tillage will influence rapid runoff for a given land-use [68]. Through evapotranspiration, trees can increase water loss and increase infiltration via their root networks, both reducing overland flow generation [69]. Watershed protection steps can also be seen in watershed planning from the perspective of soil conservation, economic and agricultural aspects, and recreational concerns [70].  
In the case of hill torrents/flash floods, the most effective measures lie with catchment management. A sudden increase in torrent kinetic energy may occur in the high regions. Technical interventions, such as tanks and inhibitory dams, can be designed for flood interception before the floods start heading to the low regions [66]. Steps taken at the catchment may help to de-synchronize the accumulation of water at points where the torrent's kinetic energy is increased. Furthermore, forest conservation measures should be considered, as they play a significant role in the prevention of flood phenomena [66].
## 5 Coexistence with IEEE 802.22 (WRAN) and Other CR Networks  
Research on the use of various CR devices in ISM and incumbent bands has been performed, but more research on the coexistence of CR devices operating in the same location will be necessary. Widely deployed CR wireless sensors use lower transmission power than other wireless network devices. Therefore, the coexistence issue between themselves and other non-CR-WSNs should be considered.  
In addition to interference, there could be opportunities to utilize the spectrum information with the cooperation of IEEE 802.22 CPEs. Although there are no reports on the possibilities of the coexistence of CR-WSNs with IEEE 802.22 RAN, it may be possible to obtain information from the CPEs and/or WRAN BS and use the spectrum information. The CPE can work as a coordinator or gateway between the CR-WSNs and WRANs.
###### Abstract  
Many algorithms have been developed for automated electrocardiogram (ECG) classification. Due to the non-stationary nature of the ECG signal, it is rather challenging to use traditional handcraft methods, such as time-based analysis of feature extraction and classification, to pave the way for machine learning implementation. This paper proposed a novel method, i.e., the ensemble of depthwise separable convolutional (DSC) neural networks for the classification of cardiac arrhythmia ECG beats. Using our proposed method, the four stages of ECG classification, i.e., QRS detection, preprocessing, feature extraction, and classification, were reduced to two steps only, i.e., QRS detection and classification. No preprocessing method was required while feature extraction was combined with classification. Moreover, to reduce the computational cost while maintaining its accuracy, several techniques were implemented, including All Convolutional Network (ACN), Batch Normalization (BN), and ensemble convolutional neural networks. The performance of the proposed ensemble CNNs were evaluated using the MIT-BIH arrhythmia database. In the training phase, around 22% of the 110,057 beats data extracted from 48 records were utilized. Using only these 22% labeled training data, our proposed algorithm was able to classify the remaining 78% of the database into 16 classes. Furthermore, the sensitivity (\(S_{n}\)), specificity (\(S_{p}\)), and positive predictivity (\(P_{p}\)), and accuracy (\(Acc\)) are 99.03%, 99.94%, 99.03%, and 99.88%, respectively. The proposed algorithm required around 180 us, which is suitable for real time application. These results showed that our proposed method outperformed other state of the art methods.  
Keywords:depthwise separable convolution (DSC); all convolutional network (ACN); batch normalization (BN); ensemble convolutional neural network (ECNN); electrocardiogram (ECG); MIT-BIH database +
Footnote †: journal: Applied Sciences
# A Multi-Resolution Approach to GAN-Based Speech Enhancement
## 4 Experimental Settings  
### Dataset  
We used a publicly available dataset in [34] for evaluating the performance of the proposed speech enhancement technique. The dataset consists of 30 speakers from the Voice Bank corpus [35], and used 28 speakers (14 male and 14 female) for the training set (11572 utterances) and 2 speakers (one male and one female) for the test set (824 utterances). The training set simulated a total of 40 noisy conditions with 10 different noise sources (2 artificial and 8 from the DEMAND database [36]) at signal-to-noise ratios (SNRs) of 0, 5, 10, and 15 dB. The test set was created using 5 noise sources (living room, office, bus, cafeteria, and public square noise from the DEMAND database), which were different from the training noises, added at SNRs 2.5, 7.5, 12.5, and 17.5 dB. The training and test sets were down-sampled from 48 kHz to 16 kHz.
## 7 High-Strength Rotor Materials  
For high-speed rotors high tensile strength and low material density of the rotor material applied are essential. In designing a propulsion system, the following criterion of  
Figure 5: Generation of rotor unbalance (application example): 51 rotor disc, 52 rotor bearing, 53 and 54 unbalance actuators, fixed at the rotor.  
strength theory must be considered: In a high-speed rotating rotor (balanced), the tangential component of the surface stress \(s_{t}\) must not exceed the tensile strength of the rotor material:  
\[s_{t}=\rho\ v^{2}R<maximum\ tensile\ strength\ s_{max} \tag{43}\]  
The component of the surface stress \(s_{t}\) itself is proportional to the material density \(\rho\) and the square of the circumferential velocity \(v_{R}\) of the rotor. This is determined by:  
\[v_{R}=2\pi Rf \tag{44}\]  
Therefore, we have the following:  
\[4\pi^{2}f^{2}R^{2}<s_{max}\]  
\[fR<\frac{1}{2\pi}*\sqrt{\frac{s_{max}}{\rho}} \tag{45}\]  
This formula says the optimized rotor material should have tensile strength \(s_{max}\) as large as possible, and its density \(\rho\) should be as low as possible. Rotors built by using this optimized material allow large magnitudes of the critical product \(fR\), i.e., high rotation frequencies f in combination with the large radius \(R\) of big-sized rotors. Permissible tensile strength should include additional stresses by the centrifugal force of the unbalanced mass.  
Our calculation results for some metallic materials and for carbon nanomaterials are shown in Figure 6:  
We draw the following conclusion: Using present metallic rotor materials, radii in the sub-meter range can be achieved for speeds of 100-1000 rps, especially with carbon-fiber-reinforced polymer (CFRP) wrapped steel rotors, as described in [21]. Furthermore, based on some success in younger experiments with nanomaterials [21; 22; 23], single-walled carbon nanotubes theoretically possess ultimate intrinsic tensile strengths in the 100-200 GPa range, among the highest in existing materials. We are so free to state here: The highest rotor speeds (1000 rps) could be achieved when using ultra-stabile carbon nanomaterial structures because this technology could be combined with allowable rotor radii in the order of several meters. Let us compare these demands to the state-of-the-art rotor equipment: CNC tool machine spindles (80 mm) make 250 rps, standard commercial high-speed ball bearings perform 350 rps, and magnetic bearings work up to 500,000 rpm, and more; see [14; 25].  
Figure 6: Highest rotation frequencies \(\frac{f_{0}}{s}\) in dependence of radius \(R\) and parameter \(\frac{s_{max}}{\rho}\) for selected materials according to Equation (45), material data according to [21; 22; 23; 24].  
Of course, there is always an alternative way of creating high thrust by means of pulse-modulated force propulsion: Instead of a single super rotor with a large radius, a battery of several smaller rotors (mounted on a common vehicle platform) can be applied, operated with synchronous unbalance control so that the individual propulsion forces add up.
# Heavy Metals in Urban Street Dust: Health Risk Assessment (Lublin City, E Poland)
###### Abstract  
Various pollutants, including heavy metals, present in street dust can pose a threat to the health of city dwellers. So far, studies on levels of this threat have been carried out mainly in large cities, characterised by considerable road traffic and industrial activity. This paper assesses the levels of hazard index and cancer risk for Cd, Cr, Cu, Ni, Pb and Zn contained in street dust collected in 2013 and 2018 at 62 points located in different parts of a small/medium-sized city (Lublin, E Poland). Heavy metals contents were analysed by means of XRF spectrometry (in the fraction <63 \(\upmu\)m). Despite the fact that the concentrations of some elements (Zn, Cd and Cu) in street dust are 6-7 times higher than the geochemical background, this does not pose a risk of non-carcinogenic effects. The average hazard index (HI) for the individual elements reaches very low levels (<0.01). Cancer risk (CR) for adults is below the less strict limit of \(10^{-4}\), and in the case of Pb, it is even lower than values of the order of \(10^{-6}\), whereas for children, CR levels exceed the standards and are of the order of \(10^{-4}\), except for Pb. For all metals except Cr, the health risk was higher in 2013 than in 2018.  
geochemistry; public  
indices for a quantitative description of non-carcinogenic and carcinogenic risks related to human exposure to heavy metals contained in street dust [22; 23; 24; 25; 26; 27; 28; 29; 30].  
The objective of this study was to assess the spatial and temporal variation in health risk posed by heavy metals contained in street dust in the area of Lublin. The content of Cd, Cr, Cu, Ni, Pb and Zn, commonly regarded as the most serious sources of pollution in urban areas, was analysed [6; 31; 32]. The heavy metal content in street dust in Lublin had already been studied [32; 33]. There are no studies determining the spatial distribution of health risk within the city of Lublin. So far research on this problem has been conducted mainly in cities with a high impact of industrial emissions, which currently do not seem to be a very important source of pollution in Lublin. Our research fills the gap related to the health risks caused by heavy metals in street dust in medium-sized cities without an intensive industrial impact.