esa-sceva/satcom-chunk-collection huggingface dataset:
# TSNetIQ: High-Resolution DOA Estimation of UAVs Using Microphone Arrays
## 4 Simulation  
### Simulation Settings  
The total procedure of the simulation is shown in Figure 3 and the specifications of the circular microphone array hardware are presented in Table 1. Pyroomacoustics Python package was used to perform the simulation and generate datasets. This library is a Python package for room acoustic simulation and audio signal processing, primarily used to create room impulse response (RIR) simulations and conduct various audio-processing experiments in these simulated environments. This experiment first simulated a 3D anechoic chamber, then added a single sound source at [2, 0, 1.5] and a microphone array at [2, 2.5, 0.05]. The 0\({}^{\circ}\) azimuth reference line of the microphone array is aligned with the sound source. The number of array elements in the microphone array \(M\) was set to 4, 6, 8, 10, and 12. The audio added to the sound source was a 5 s sinusoidal signal generated using the scipy package, with a frequency of 2000 Hz, a default sampling rate \(f_{\mathrm{s}}=4200\) Hz, and a fixed sampling time \(T=3\) s. The positions of the sound source and microphone array are reasonably configured, with the element spacing fixed at 0.02 m, and Gaussian white noise was added to the anechoic chamber to maintain an SNR of 5 dB. Adjustments when training under different SNRs can be made manually. The dataset generation process is initiated by simulating the scenario in which the sound source emits signals and the microphone array receives them.  
\begin{table}
\begin{tabular}{l c c} \hline \hline
**Parameter** & **Specification** & **Description** \\ \hline Maximum Number of Elements & 64 & Supports up to 64 microphones in the array \\ Array Diameter & 150 mm & Total diameter of the circular microphone array \\ Operating Frequency Range & 20 Hz–80 kHz & Effective acoustic signal reception bandwidth \\ Sampling Method & Continuous and synchronous sampling & All microphones are sampled in parallel and in sync \\ \hline \hline \end{tabular}
\end{table}
Table 1: Specifications of the circular microphone array hardware.
## 2 Public Safety Network
### IoT Devices for Public Safety  
IoT devices can play a vital role in enhancing the performance of a public safety network in terms of accuracy, efficiency, and predictability [45]. Furthermore, IoT devices have to analyze, aggregate information, and transmit without human intervention. This ensures the accuracy of received information and enhances the ability to anticipate crimes and other incidents. It is helpful to predict where crimes and natural disasters are more likely to occur. Figure 6 shows the classification of IoT for disaster management, which includes natural, manmade, service orientation, and post-disaster. Natural disasters include floods, earthquakes, landslides, etc.; however, the post-disaster focus is only on saving victims in their locations. On the other hand, IoT for service-oriented disaster management has been discussed in [67; 68; 69].
## 1 Introduction
This automatically results into the weakening of the transmission of the common mode signal. Magnetic coupling has also been used for the design of dual-band BPF [42] by using embedded resonators printed on a monolayer structure in order to achieve dual-band operation. Once again, it was proven that magnetic coupling provided an ideal mechanism to reject the common-mode noise. However, the main drawback of the design presented in [42] was the independent control of the features of the two passbands, since both bands were dependent from each other. This is a fact inherent to the use of embedded resonators. Furthermore, in [43; 44] the use of magnetic coupling has been extended to the design of balanced diplexers with excellent results that confirm the benefits and flexibility offered by magnetic coupling to design different kinds of differential components. The contribution made in [42] has motivated the authors to present in this paper a different strategy to design balanced dual-band BPFs with more flexibility and independence in what concerns the tuning the two differential passbands. As a case example, the proposed technique is used to design a filter with two differential bands corresponding to two commonly used wireless communications standards (GPS and Wi-Fi bands). It will be shown how, by using a multilayer structure, it is possible to create two differential passbands that can be independently tuned. Two magnetically coupled resonators on the top layer create the upper differential passband, while the lower differential passband is originated from another pair of resonators etched in the middle layer. These resonators are also magnetically coupled. Top layer resonators are excited by means of a edge gap capacitance between the feeding lines and the resonators. Middle layer resonators are excited thanks to the broadside capacitance created between the top and middle layers. Very good DM and CM responses can be achieved using this method, which is experimentally demonstrated for a filter based on two pairs of magnetically coupled open-loop resonators. The most relevant features of the proposed design are: (i) the two differential passbands are almost totally independent due to the asynchronous nature of the resonators and the possibility of independent control of the resonators excitation, (ii) band-to-band isolation about 36 dB can be easily achieved, and (iii) a good CM rejection level, which is inherent to magnetic coupling, can be also easily obtained (more specifically, 39/33 dB measured in the lower/upper DM passbands, respectively).
# LR-MPIBS: A LoRa-Based Maritime Position-Indicating Beacon System
## 3 Results and Discussion
### Initial Satellite-Search Performance Test of PIT  
The time from the moment of man overboard to the sending of the first accurate positioning data is key to efficient rescue. This includes the time of falling into the water and searching for satellites. In this work, a cold start time of satellite search comparison testing of self-developed PIT and commercially available beacon device PL01 (designed by Panco Intelligence) was conducted in urban, mountaintop, and sea-surface environments. The experimental results are shown in Figure 9.  
It was found that the PIT developed in this work is able to stably complete accurate positioning within 60 s in all kinds of environments. The average time of satellite search, no more than 50 s, is comparable to commercially available products. In addition, excellent repeatability was found in the satellite search time of the PIT.
## 7 Simulation Results
### Energy Consumption  
Energy usage and dead nodes are significant concerns regarding power management in Wireless Sensor Networks or comparable systems. Dead nodes can affect system performance and conflict with network activities. The average and total distances for the  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Protocol Name** & **X** & **Y** & \multicolumn{2}{c}{**Distance (m)**} & \multicolumn{1}{c}{**Results for**} \\  & **(m)** & **(m)** & \multicolumn{1}{c}{**Distance (m)**} & \multicolumn{1}{c}{**Protocols with**} \\  & & & & **KNN** \\ \hline LEACH & 0.781 & 13.081 & 61.526 & \\ LEACH-KNN & 98.796 & 43.152 & 49.274 & 20\% closer to BS \\ \hline SEP & 98.503 & 94.137 & 65.580 & \\ SEP-KNN & 78.719 & 92.470 & 51.269 & 21.9\% closer to BS \\ \hline TEEN & 1.900 & 8.722 & 63.382 & \\ TEEN-KNN & 13.077 & 28.485 & 42.733 & 32.6\% closer to BS \\ \hline DEC & 19.465 & 85.605 & 46.905 & \\ DEC-KNN & 35.572 & 87.204 & 39.903 & 15\% closer to BS \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparison of the longest distance between CH and base station for original and modified protocol.  
Figure 13: Average distance per node in the original and modified protocols.  
modified approach were lower than those for the original protocol, as mentioned in the previous section. Therefore, CHS's average energy consumption and the network's overall energy consumption will be less than the original protocols. Table 4 shows the network's energy summation, and Figure 14 shows the average energy consumption per node.
# Preliminary Analysis of the Water Quality Status in an Urban Mediterranean River
## 1 Introduction
PAHs are included in the list of priority substances of the Water Framework Directive (WFD) 2000/60/EC, established in the No 2455/2001/EC amendment. PAHs are hazardous organic compounds released into the environment by natural and anthropogenic combustion processes alike. Considerable attention has been paid to PAHs due to their documented carcinogenicity [13] and their persistent nature. Natural sources include volcanic eruptions and forest fires, while incomplete combustion of transportation fuel, industrial waste, agricultural fires and waste incineration constitute examples of anthropogenic sources [9; 14]. The purpose of this preliminary study is to investigate the impacts of urbanization on river pollution and the implications for recreational use. The main objective is to assess the physicochemical and microbial quality of the Kifisos river in Attica Greece, which comprises a typical example of an urban river prone to environmental degradation mainly due to its proximity to several pollution sources. We should point out that the Kifisos river is the main urban river of the capital city of Greece (Athens), which nevertheless is not monitored adequately regarding water pollution, and therefore, relevant information is scarce. Thus, this effort is likely the first attempt to present a recent spatiotemporal analysis of the water quality status of the river by using several variables and attempting to identify pollution hotspots along its course. To our knowledge, there is a lack of research on the relationships between physicochemical parameters, nutrients, and _E. coli_ concentrations in the Hellenic Water Quality Index (HWQI), and this fact emphasizes the necessity of this study. Descriptive statistics, box plots and correlation matrixes are employed. We analyze the following groups of pollutants: nutrients, pathogens and physicochemical parameters using monthly water surface samples from May 2021 to April 2022 from five sampling sites. Measurements of total polycyclic aromatic hydrocarbons (TPAHs) and total hydrocarbons (THs) were also collected in two of the campaigns in May 2021 and September 2022. Additionally, _E. coli_ monitoring results are corelated with the Hellenic Water Quality Index (HWQI) [15; 16; 17; 18; 19] according to the demands of the WFD 2000/60 EC to investigate potential relationships. This is a first attempt to investigate correlations between _E. coli_ and HWQI in an urban river, which is crucial for future water quality assessments. The data presented here can be used to provide valuable insights and contribute to the development of comprehensive and inclusive management and restoration plans to tackle the degradation of urban water bodies and their in-stream habitats.
###### Abstract
\begin{table}
\begin{tabular}{l l l l} \hline \hline
**Method** & \multicolumn{2}{c}{**Advantages**} & \multicolumn{1}{c}{**Disadvantages**} \\ \hline Visual inspection & & & \\  & \(\bullet\) & Cheap & \(\bullet\) & Skilled working force needed \\  & \(\bullet\) & Fast (or no) preparation & \(\bullet\) & Detection of only larger defects \\  & \(\bullet\) & Immediate results & \(\bullet\) & Possible misinterpretation of cracks \\  & \(\bullet\) & Non-destructive & \\ Stress wave transmission & & & \\  & \(\bullet\) & The presence of reinforcements or moisture do & \(\bullet\) & The results should be used for qualitative purposes \\  & \(\bullet\) & Non-destructive & \(\bullet\) & Highly affected by moisture and salt content \\ Ultrasonic \& sonic velocity & & \\ testing, acoustic emission & & Fast and higher accuracy in results & \(\bullet\) & High skilled and educated working force needed \\  & & Non-destructive method & \(\bullet\) & Misreading of signals \\  & \(\bullet\) & Accessibility to just one side of the & \(\bullet\) & Wrong interpretation of data \\  & \(\bullet\) & element needed & \(\bullet\) & Transducers must be coupled on the material surface \\  & \(\bullet\) & Not affected by moisture & \(\bullet\) & Small defects can affect results \\ Impact echo & & & \\  & \(\bullet\) & Non-destructive method & \(\bullet\) & Slow method – requires a lot of measurements to map \\  & \(\bullet\) & Accessibility to just one side of the & \(\bullet\) & larger regions \\  & & element needed & \(\bullet\) & Stress wave energy is reflected at air boundaries \\ Surface penetrating radar & & & \\  & \(\bullet\) & Cracks, bonds, delamination does not affect & \(\bullet\) & Relatively expensive \\  & \(\bullet\) & the results & \(\bullet\) & Mortar interfaces can mask energy reflected from \\  & \(\bullet\) & Fast method & \(\bullet\) & points of interest \\  & \(\bullet\) & Non-destructive method & \\  & \(\bullet\) & Possibility to investigate different conditions & \\  & & such as salt content and moisture content, & \\  & & location of reinforcements, deterioration, etc. & \\ Rebound hammer test & & & \\  & \(\bullet\) & Ease of use & \(\bullet\) & Results are for a local point \\  & \(\bullet\) & Relatively cheap & \(\bullet\) & The results are not directly related to the strength \\  & \(\bullet\) & Fast method & \(\bullet\) & of surface \\  & & & \\  & & & \\  & & & \\  & & & \\  & & & \\ Flatjack system & & & \\  & & & \\  & & & \\  & & & \\  & & & \\  & & & \\  & & & \\  & & & \\  & & & \\  & & & \\  & & & \\ \end{tabular}
\end{table} 
Table 1: Basic advantages and disadvantages of NDT and semi-NDT inspection methods for existing masonry structures.
## 2 Problem Formulation
### Task Design Objective and Problem Definition  
To interact with the external environment in the mobile robot system, various sensors are installed on the mobile robot to detect real time useful information. This paper uses the detection mechanism as shown in Figure 2 for visual representation, which means only local environmental information is available. It enables the mobile robot to have a total number of \(m\) laser distance sensors to detect whether there are any obstacles around it and how far away the obstacle is from its current position, and this information is denoted as \(d_{i}(t),i=1,\ldots,m\).  
Figure 1: An exemplary operation environment of the mobile robot navigation task.  
Note that the green lines in the figure are the laser beams, which will reflect after touching an obstacle. These laser beams can detect the obstacles within a maximum distance of \(d_{max}\); hence, there exists \(0\leqslant d_{i}(t)\leqslant d_{max}\). Furthermore, a location sensor is incorporated to calculate the bias of the heading direction, which is the red arrow in the figure, and is denoted as \(\phi(t)\) satisfying \(-180^{\circ}<\phi(t)\leqslant 180^{\circ}\).  
In this sense, the design objective of the autonomous mobile robot navigation task is to develop a mechanism, which makes the vehicle respond to the real time environmental information in order to complete the task. The navigation problem discussed in this paper is explained in the next definition.  
**Definition 1**.: _The **autonomous mobile robot navigation problem with obstacle avoidance** aims to make appropriate decisions of the given motion types based on the real-time detected information \(d_{i}(t)\), \(i=1,\ldots,m\) and \(\phi(t)\) at each sample time index \(t\), such that the vehicle moves from its start position \((x_{0},\ y_{0})\) to a position \((x^{*},\ y^{*})\) close to its destination position \((x^{d},\ y^{d})\) without colliding with any single obstacle, i.e.,_  
\[\left\|(x^{*},\ y^{*})-(x^{d},\ y^{d})\right\|\leqslant\epsilon, \tag{4}\]  
_where \(\epsilon\) is a small positive scalar determining an acceptable distance from the destination to complete the navigation task._  
The above definition articulates a nontrivial decision-making problem, which is not deterministic or straightforward to solve. Therefore, this paper will employ the tools of a neural network and supervised learning to address this problem in Section 3 in the sense of replicating the human decision process using obtained data. Note that the human decision-making process is the procedure where human drivers make the motion decisions when in the same situation, i.e., with the same local information. In this process, the human drivers would try their best to reach the destination via a relatively short path without colliding with the surrounding obstacles.
## Results and Discussion
### Volatile Compounds of Portuguese Honeys  
Ninety eight volatile compounds of different class were tentatively identified and semi-quantified using a response factor equal to 1 for all the compounds [8; 34] (Table 4). In Table 4 are listed the compounds that were identified with a qualification MS value of \(\geq\)83. The volatile compounds of eucalyptus, chestnut and heather honeys could be classified as alcohols, aldehydes, benzene derivatives, hydrocarbons, esters, furan derivatives, ketones, norisoprenoids, phenolic volatiles, terpenoids, sulphur volatiles and so forth. What is remarkable is that volatiles were significantly affected (\(p<0.05\)) by honey botanical (Table 4) and geographical origin (data not shown). Total volatile compounds semi quantitative data (\(\mu\)g/kg) of Portuguese honeys followed the sequence: heather (21,257.17 \(\pm\) 1051.56) > eucalyptus (8488.22 \(\pm\) 3180.80) > chestnut (8448.52 \(\pm\) 1626.72). Many of these compounds comprise some typical volatile markers of monofloral honeys harvested in different parts of the world [8; 34; 44; 45]. Typical gas chromatograms of eucalyptus, chestnut and heather honeys are shown in Figures 1-3, indicating with numbers some characteristic volatile markers according to honey botanical origin. Figure 1: A typical gas chromatogram of eucalyptus honey from the region of Viseu, Oliveira de Frades in Portugal. 1: 2-Butanone. 2: Octane. 3: alpha-Phellandrene. 4: Linalool. 5: 2-Buten-1-one. 6: 2,6-bis-(1,1-trimethyl)-2,5-cyclohexadiene-1,4-dione. 7: alpha-Calacrene. 8: Bycílo [5.3.0] decapentaene. IS: Internal standard.
## 6 Results
### Extrapolation to Full Scale Performance  
The full-scale hydrodynamic performance of the optimal hull form can be predicted by the 2-D extrapolation of ITTC 1978 performance prediction method. Firstly, the residuary resistance coefficient \(C_{R}\) needs to be calculated from the \(C_{TM}\) obtained by the RANS solver and the frictional resistance coefficient in model scale using \(C_{R}=C_{TM}-C_{FM}\) and \(C_{FM}=\frac{0.075}{\left(\log_{10}Rn_{M}-2\right)^{2}}\).  
Then the extrapolation to full scale is carried out as follows:  
\[C_{FS}=\frac{0.075}{\left(\log_{10}Rn_{S}-2\right)^{2}} \tag{19}\]  
\[C_{TS}=\frac{S_{S}+S_{BK}}{S_{S}}(C_{FS}+C_{A})+C_{R}+C_{AA} \tag{20}\]  
\[R_{TS}=C_{TS}\frac{1}{2}\rho_{S}S_{S}V_{S}^{2} \tag{21}\]  
\[P_{E}=R_{TS}V_{S} \tag{22}\]  
Here, the model-ship correlation allowance \(C_{A}=-0.0002\) was used. The air resistance coefficient is given as \(C_{AA}=0.001\frac{A_{TS}}{S_{S}}\) using the transverse area over waterline \(A_{TS}=817\) m\({}^{2}\). \(S_{S}\) and \(S_{BK}=123\) m\({}^{2}\) denote the wetted surface area and the bilge keel area of full scale, respectively. Table 11 summarizes the relevant quantities involved in the full-scale extrapolation procedure for the original hull and the optimal hull. As seen, the present hull form optimization study achieved a 3.1% reduction in the effective power at the design speed of 24.0 knots (\(Fn=0.260\)).  
Finally, Figure 12 displays the predicted values of \(P_{E}\) of the optimal hull as a function of speed ranging from 20 to 26 knots in comparison to those of the original hull. At each speed, the percentage reduction in \(P_{E}\) is marked, which increases with increasing speed. Since the present hull form optimization is aimed at the reduction of wavemaking resistance, the performance improvement becomes larger at higher speeds when the wavemaking resistance becomes more dominant. In conclusion, the optimal hull form yielded performance improvement over the original hull form in a wider speed range, including the design speed.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \multirow{2}{*}{**Hull Form**} & **Wetted** & & & & & & & \\  & **Surface** & **Area (m\({}^{3}\))** & & & & & & \\  & & & & & & & & \\ \hline Original & 9495 & 3.629 & 2.831 & 0.798 & 1.378 & 2.078 & 1542.7 & 19,047 \\ Optimal & 9497 & 3.564 & 2.831 & 0.733 & 1.378 & 2.012 & 1494.5 & 18,452 \\  & & (98.2\%) & & (91.9\%) & & (96.8\%) & & (96.9\%) \\ \hline \end{tabular}
\end{table}
Table 11: Comparison of full-scale performance prediction between original and optimal hull forms at the design speed \(V_{S}=24.0\) knots (\(Fn=0.260\) ).
## 3 Experimental Results and Discussion
### Load and Deflection Relationship
#### 3.2.1 Textile Reinforcement Ratio  
Figure 8 shows flexural behavior of the control, T1, T2, and T3 specimens according to the textile reinforcement ratio. The yield and ultimate loads of the control specimen were 32.06 kN and 35.39 kN, respectively. The yield load of T1 was 33.66 kN, which was 5% higher than that of the control specimen. As for T2, its yield and ultimate loads were 34.89 kN and 36.49 kN, respectively, which were 9% and 3% higher than that of the control specimen, respectively. For T3, its yield and ultimate loads were 38.71 kN and 41.92 kN, respectively, which were 21% and 18% higher than the control specimen, respectively. The strengthening effect of T1 and T2 was negligible because the ratio of increasing strength was less than 10%. In particular, the textile reinforcement ratio of T2 was twice that of T1, but the ratio of increase of  
non-impregnated textile in the crack increased with the increase of the load, and the strengthening efficiency decreased sharply.  
The T3 showed sufficient improvement with higher ratio of increase of strength compared with T1 and T2. As shown in Table 6, T3 had similar load-bearing capacity of T2E, T2A, and T2 AP with end anchor because there was enough textile to bear the load even if some of textile of the T3 was damaged. T2E, T2A, and T2 AP were considered to be free of textile damage due to anchor. This is discussed in detail in Section 3.2.3. The higher the ratio of textile reinforcement, the more sufficient load-bearing capacity appears even if damage to the non-impregnated textile occurred.