esa-sceva/satcom-chunk-collection huggingface dataset:
## 5 Long-Short-Range Communication
### Long-Range Communication
#### 5.1.2 LoRaWAN and LoRa  
The basic and technical information for these two standards is mentioned in by the LoRa alliance. LoRa is a protocol function in the physical layer that uses a chirp spread spectrum approach with a wide bandwidth of nearly 125 kHz, providing long-range transmission, low power and good flexibility to environmental interference. LoRa WAN is constructed using the LoRa standard, and it follows a star topology network with asynchronous nodes and required communication when necessary. It uses scheduled messages from nodes that are suitable for long-term tracking applications, whereas event-based messages are used for emergency tracking. The high network capacity feature of LoRa WAN allows multiple messages to pass through forty thousand nodes. It has been implemented in various parts of Asia-Pacific, Europe and America, and with a high link budget of 155 dBm, information can transfer in a range of up to 5.5 kbps, which is considerably faster than Sigfox; this trade-off is valuable, as it enables a short delay that is essential for healthcare applications. It also operates on the unlicensed band at 915 MHz in the US and 868 MHz in Europe, offering advantages in terms of broad-spectrum accessibility. LoRa WAN is suitable for healthcare applications because of its network capacity, range and latency. Interference may be an issue, as it operates in an unlicensed band.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameters** & **IoT (NB)** & **Big Fox** & **LoRa WAN** \\ \hline Operating Band & \begin{tabular}{c} In-band LTE mode, \\ guard-band LTE \\ \end{tabular} & \begin{tabular}{c} 915 MHz for US and 868 MHz \\ for Europe \\ \end{tabular} & \begin{tabular}{c} 915 MHz for US and 868 MHz \\ for Europe \\ \end{tabular} \\ \hline License required & Yes & No & No \\ \hline Approx. range & 16 km & 10 km & 7 km \\ \hline Rate of data & 250 kbps & 120 kbps & Up to 6 kbps \\ \hline Capacity of network & 54,000 nodes & 55,000 nodes & 42,000 nodes \\ \hline Relevance for health care & Good & Poor & Average \\ \hline Direction of communication & Downlink and uplink & \begin{tabular}{c} Request for downlink and \\ uplink facility is unlimited \\ \end{tabular} & Downlink and uplink \\ \hline Safety attributes & \begin{tabular}{c} Security enabled with S3 (3G \\ PP), which includes \\ authentication, recognition \\ and confidentiality with data \\ integrity \\ \end{tabular} & \
\begin{tabular}{c} A private key is used with a \\ limited of 142 messages with \\ scrambling and encryption \\ enabled \\ \end{tabular} &
\begin{tabular}{c} Each node is assigned a \\ unique key in the network, \\ which is known to the \\ network and supports data \\ encryption \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table}
Table 1: Comparison of long-distance communication standards.
# Detection and Localization of Multiple Damages through Entropy in Information Theory
## 5 Results
### Potential Applications for Supervised Learning  
To conclude this investigation, it might be useful to say that, if available, a catalog of expected entropy changes caused by different damage typologies (such as the ones described in Section 3) could be used for supervised learning, providing a machine learning (ML) system with some damage classification (or even damage prognosis) capabilities. However, these aspects will require further studies.
## 6 MZI and Waveguide Crossing Characteristics
We compared the four topologies discussed before, based on these performances; Figure 10 shows \(\hat{\mathcal{SC}}R\) values for each of them. DLN scales better than the others did, a \(32\times 32\) switch can be fabricated with an \(\hat{\mathcal{SC}}R\geq 20\) dB. However, we can notice that it is badly impacted by the first-order MZI crosstalk generated at the center stage, unlike dilated Benes and S&S, whose \(\hat{\mathcal{SC}}R\)s are over 40 dB for \(N=4\). \(\hat{\mathcal{SC}}R\) values of dilated Benes is quite good on a small scale (N \(\leq 16\)), but waveguide crossings loss (0.1 dB/crossing) badly affect its performance for the higher scale. Benes is a good topology because its \(\hat{\mathcal{SC}}R\) does not drop quickly. Nevertheless, it requires further optimization of first-order MZI crosstalk. The high number of waveguide crossings in S&S is still a real issue; we think it is not adequate for our technology. Other topologies could be analyzed using our SCR analytical model to choose the most suitable. Figure 9: (**a**) Insertion loss measured of \(2\times 2\) MZI by varying the biased current separately in the two-phase shifters. (**b**) Transmission signal spectrum (in dB) of the loop-back waveguide and the MZI in bar and cross-states. (**c**) Measured transmission spectra (in dB) of waveguide crossing (dark lines) and crosstalk recorded (blue lines).
## 4 Key Enabling Techniques
### Beamforming  
The smart antenna technique which consists of a closed-loop pre-coding where we can steer the wireless beam flexibly toward the desired subscriber is called beamforming. It is proven technology for improved array gain, signal quality, network coverage, higher channel capacity, SE, and reduced inter-cell interference. It employs digital signal processing techniques that identify the directional antenna beam patterns by using several antennas at the transmitter side. Smart antennas equipped with beamforming abilities can be organized such that the transmitted signal can be directed to the desired location with exact precision and avoid unwanted signals from an undesired path simultaneously. It can be rotated electronically by phase shifting in 5G networks. The impact of suitable antenna configurations for directional multi-antenna beamforming have shown to improve the Ricean factor gain, increased SNR and low root-mean-squared (RMS) delay spread because of multi-path dispersion at the receiver. Beamforming consists of two-dimensional beamforming (2 DBF) and three-dimensional beamforming (3 DBF). By using narrow pencil beams, spatial degrees of freedom can be exploited by avoiding inter-cell interference [18; 110; 111]. Therefore, beamforming is considered to be key player for improving SE.
# An Adaptive Symmetrical Load Balancing Scheme for Next Generation Wireless Networks
## 3 Methodology  
The overall architecture proposed in the research is depicted in Figure 1. The application plane carries the ASLB scheme to achieve load balancing in data and control plane. The control plane has multiple SDN controllers. The control plane has two tiers, namely the UC and RCs. The UC is responsible to monitor the RCs and shift the flows to the most underloaded RC. AHP is used to filter the flows and the most delay sensitive flow is forwarded first to the UC to minimized delay and enhance throughput at the user end.  
The data plane has all the forwarding devices. The UC keeps track of load reports of all the APs. Once the AP becomes overloaded the controller using OpenFlow deassociates the WD and re-associates it to the least-loaded AP.  
The proposed ASLB works in two planes as depicted in Figure 2. Symmetrical load balancing at the control plane and data plane is achieved side by side. Symmetry of load balancing is achieved, as the load among the APs in the data plane and load among the controllers in the control plane is balanced.  
In the multi-controller SDN architecture, a UC is designated to supervise other RCs in terms of processing time, memory and response time. Upon the arrival of a new flow at the switch, the switch inspects the initial flow packet and categorizes it into various classes. The switch requests the UC to calculate the corresponding flow strategies. The UC may assign the request to a RC for flow processing. The UC is responsible for organizing the regional controllers into three types of clusters comprising OUC, ULC and NUC.  
The UC employs the ASLB technique to distribute the flow requests to relevant RCs for computing flow policies and then deploys the policies back at the switch to achieve a high processing rate and low response time for the requests. The ASLB is adaptive to any network wise traffic condition. The symmetry of load is maintained among the APs in the data plane and multiple controllers in the control plane. In the past, AHP technique has been utilized in numerous applications such as planning, resource allocation, and priority  
Figure 1: SD-WiFi architecture.  
Figure 2: The proposed ASLB.  
setting for precise decision making and selecting the optimal SDN controller from a list of controllers [40]. In the data plane the ASLBs mutually analyze the handoff process and access information of both AP-side and WD-side data to attain load balancing.
###### Abstract  
Transmitter and receiver position errors have been known to significantly deteriorate target localization accuracy in a multi-static passive radar (MPR) system. This paper explores the use of calibration targets, whose positions are known to the MPR system, to counter the loss in target localization accuracy arising from transmitter/receiver position errors. This paper firstly evaluates the Cramer-Rao lower bound (CRLB) for bistatic range (BR)-based target localization with calibration targets, which analytically indicates the potential of calibration targets in enhancing localization accuracy. After that, this paper proposes a novel closed-form solution, which includes two steps: calibration step and localization step. Firstly, the calibration step is devoted to refine the inaccurate transmitter and receiver locations using the BR measurements from the calibration targets, and then in the calibration step, the target localization can be accurately achieved by using the refined transmitter/receiver positions and the BR measurements from the unknown target. Theoretical analysis and simulation results indicate that the proposed method can attain the CRLB at moderate measurement noise level, and exhibits the superiority of localization accuracy over existing algorithms.  
multi-static passive radar; target localization; calibration target; bistatic range; transmitter and receiver position error; Cramer-Rao lower bound +
Footnote †: journal: Sensors
# Radiation-Induced Structural Changes of _Miscanthus_ Biomass
## 3 Results and Discussion  
### Effect of Irradiation Treatment on Chemical Compositions of _Miscantthus_ Biomass  
The composition changes of _Miscantthus_ biomass after different absorbed doses are presented in Table 1. As shown in Table 1, the main components of _Miscantthus_ are cellulose, hemicellulose, and lignin, and their total content accounts for 89.7%. In comparison with the compositions of giant need and Chinese silvergrass reported in the literature, _Miscantthus_ has the same contents of holocellulose and lignin as giant reed, and the total content is higher than Chinese silvergrass [18]. After irradiation treatment, the contents of cellulose and hemicellulose of _Miscantthus_ decreased with the increase in absorbed doses up to 1200 kGy, and irradiation treatment had little influence on lignin content. That is, the content of lignin before and after irradiation treatment was almost stable. These phenomena were confirmed by other researches [18; 21]. The structure of destroyed cellulose can improve enzymatic hydrolysis during downstream saccharification [13]. To illustrate why irradiation has a significant effect on cellulose and hemicellulose but little effect on lignin, the biomass structure was comprehensively elucidated by FTIR, TGA, XRD, GPC, a laser particle size analyzer, SEM, AFM, and NMR in this work.
# Embedded Based Real-Time Monitoring in the High-Pressure Resin Transfer Molding Process for CFRP
## 2 High-Pressure RTM  
### HP-RTM Process Parameter  
Figure 1 shows a detailed view of the HP-RTM process. Due to the high-pressure force applied to the mold and the high injection pressure in the mixing head, the HP-RTM forms a fast resin flow within the cavity mold. The epoxy resin supply system consists of a temperature-controlled storage tank of resin and hardener, metering pumps, and piping lines. The storage tank maintains the resin at a constant temperature makes the resin in the mixing head to be injected easily. The high-pressure metering pump discharges at a constant flow rate and the piping line minimizes heat loss during the circulation of resin by the hot wire. In the HP-RTM process, a carbon fiber preform is placed on the mold, the mold gap is maintained constant, and the resin and curing agent are mixed at high pressure in  
the mixing head and then injected into the preform. When the resin is filled, the laminate is compressed by pressing. Here, the resin diffuses from the upper surface to the lower surface (i.e., vertically) by compression force. The impregnation rate can be increased by the vacuum and temperature in the mold, the compression force, the mold opening/closing speed, and so on, when the carbon fiber preform is impregnated with resin.  
Figure 2 shows the process parameters of HP-RTM. The HP-RTM parameters that affecting the molding quality in the HP-RTM process include the initial temperature of the storage tank, the discharge of resin from the metering pump, the resin temperature and injection pressure of the mixing head, the compression force of the press, the temperature and pressure of the mold, the pressure, end-gap, mold opening/closing time, and vacuum. The temperature factor determines the viscosity of the resin. When the temperature of the resin is low, injection is difficult due to the low viscosity. When the temperature is high, the resin is cured before diffusing throughout the entirety of the carbon fiber preform. When the pressure of the mixing head is low in the HP-RTM injection process, the diffusion rate of the resin decreases and is cured before the impregnation of the resin has completed. When the injection pressure is high, the preform layer is distorted [22]. In the HP-RTM compression and curing step, the mold temperature forms the reaction temperature to cure the resin and the compression force is an important factor in the diffusion and impregnation of the resin, which affects the mechanical properties of CFRP, such as the tensile and flexural strength [23]. The end-gap of the mold and the mold opening/closing time affect the void generation inside the CFRP [24]. The molding cycle time is a factor related to the production efficiency, which includes the injection, compression, and curing time of the resin; furthermore, since the curing time is fast in a high-temperature mold, the forming time is reduced but the resin impregnation is difficult and the bonding force between the fiber layers remains low.  
Figure 1: Flow diagram of the HP-RTM process.
## 3 Results and Discussion
### XRD, FTIR and Raman
The vaterite allotrope of calcium carbonate, not detected in the XRD pattern, also has split FTIR peaks at \(\sim\)1420-1490 cm\({}^{-1}\)[36] but exhibits another distinctive peak at \(\sim\)750 cm\({}^{-1}\), not present in the spectra of treated Mg. Stable ACC, in contrast to the calcite and aragonite crystalline forms, does not present a sharp peak at 713 cm\({}^{-1}\)[37]. Thus the absence of a peak at 713 cm\({}^{-1}\) indicates that well -ordered calcite and/or aragonite are not present after 15 min immersion, only the presence of ACC can be determined from the FTIR analysis. The Raman spectra of Mg immersed for 1 h (Figure 5) have a strong, sharp feature at \(\sim\)1086 cm\({}^{-1}\). This band corresponds to the A\({}_{\rm 1g}\) mode of the CO\({}_{3}\) polyhedra. Additional weaker features at \(\sim\)711 cm\({}^{-1}\), \(\sim\)1433 and \(\sim\)1746 cm\({}^{-1}\) are assigned to internal E\({}_{\rm g}\) modes from the oscillations of the CO\({}_{3}\) polyhedra in calcite calcium carbonate [38]. Raman results confirm XRD results, namely that after one -hour immersion, the coating is formed by crystalline calcite CaCO\({}_{3}\). The Raman spectra after 30 min (Figure 5) also present a strong A\({}_{\rm 1g}\) mode of CO\({}_{3}\) groups in CaCO\({}_{3}\), as well as the secondary E\({}_{\rm g}\) modes. An additional weak band is observed at \(\sim\)3650 cm\({}^{-1}\). This band corresponds to OH group stretching and indicates the presence of hydroxyl groups along the CO\({}_{3}\) polyhedra. The Raman spectra after 15 min present a weak carbonate peak and the hydroxyl band at 3648 cm\({}^{-1}\) but do not show the calcite modes, therefore indicating the presence of disordered hydroxy carbonates. Figure 4: FTIR spectra showing the evolution for immersion times in carbonated water of 15 min, 30 min and 1h. The analysis by vibrational spectroscopy exhibits distinctive features indicating the deposition of disordered carbonate phases, ACC and hydroxycarbonates, after 15 min immersion, as the result of Mg immersion in carbonated water.
## 3 Analytical Methods
### Statistical Analysis of Instantaneous Resistances  
To estimate the continuous variations in the contact resistance due to the contact surface alterations encountered during movement, we have calculated the instantaneous resistance \(R(t)\) according to Equation (1):  
\[R(t)=\frac{U(t)}{I(t)} \tag{1}\]  
where \(U(t)\) and \(I(t)\) are respectively the voltage and current measured at each sampling time. It is therefore possible to monitor variations in contact resistance over extremely short time intervals, of the order of microseconds, corresponding to the oscilloscope sampling frequency of 1 MHz.  
If the roller moves over a 30 cm long rail section at a speed of 10 cm/s we obtain 3.10\({}^{6}\) measurements of \(R(t)\). Thanks to this large data set, it is possible to evaluate the variations in contact resistance observed during dynamic testing. To this end, statistical analyses have been carried out on this dataset, identifying the median and interquartile range (IQR). The median gives an indication of the central value of the resistance, while the IQR, as shown in Figure 7, is an indicator of the data homogeneity. It is calculated as the difference between the 25 th percentile and the 75 th percentile of all values. The higher the IQR width, the greater the dispersion of resistances.  
On a clean rail surface, the median value is generally low and the IQR is reduced, reflecting more homogeneous resistance values. However, on a less clean surface, the median increases and the IQR widens, indicating more dispersed resistance values.  
Figure 8 shows an example of the graphical representation of these statistical measurements (median and IQR) as a function of the current, for different applied forces and speeds. This method can therefore be used to quantitatively evaluate the electrical behavior of the wheel-rail contact for different operating conditions through statistical analysis of instantaneous resistances. It enables trends in \(U-I\) characteristics to be detected, and to identify the critical parameters that have a significant influence on the contact behavior.  
Figure 8: Schematic diagram of the graphical representation of statistical measurements—(\(\bullet\)) Median and (I) IQR—of contact resistances for different current intensities.  
Figure 7: Box plot illustrating the median and IQR (interquartile range) for a dataset.
# Adaptive Multi-Path Routing Protocol in Autonomous Vehicular Networks
## 6 Evaluation
### Evaluation Setup  
The physical model used in this paper is based on IEEE 802.11b [17]. IEEE 802.11b supports four data rates, namely, 1, 2, 5.5, and 11 Mbps. For the parameters shown in Tables 2 and 3, we refer to the specifications of the ORiNOCO PC Card [34]. The propagation model is based on the two-ray ground model of ns-2 [35]  
We use the ns-2 simulator [35] to conduct the simulations. We use the multi-rate extensions from the Rice Networks Group [36] for the implementations of RBAR based on the  
Figure 8: The probability of finding a high-throughput path (\(p\)) vs. node density (\(\delta\)). The node density (\(\delta\)) is number of nodes per m\({}^{2}\) and is presented in log scale.  
Figure 7: Node A is transmitting to node B, and the nodes are \(R_{2}\) distance apart.  
ns-2.1b7a code. We have also directly adopted the metric values used in [26] for multi-rate-aware routing as shown in Table 3. The medium time metric is the normalized estimated medium time for a 1500-byte payload to be transmitted using 802.11b with RTS/CTS.
## 3 Results and Discussion
### Dispersion Stability Analysis
Under different abrasive concentrations, Sample 2 (0.5 wt%), Sample 3 (1.0 wt%), Sample 4 (1.5 wt%), and Sample 5 (2.0 wt%) all exhibited excellent dispersion stability without noticeable delamination; however, Sample 6 (3.0 wt%) showed slight delamination. Based on these experiments, it can be inferred that the phosphoric ester compounds dispersant displays superior dispersion stability compared to that of Na(PO3)6 and PEG.
###### Abstract
In this study, since the reliability of the soft information generated by the 1D SOVA detectors was affected by defects in the readback signals, this reliability must be carefully addressed. Generally, these defects are primarily caused by 2D interference and media noise. To improve the detection process, we propose enhancing the soft information output produced by the 1D SOVA detector before making a final decision. This can be achieved through four proposed techniques, namely, hard-information flipping (HIF), maximum soft-information (MSI) finding, bit-summation detection (BSD), and MLP application. These proposed techniques can operate together with the staggered bit island arrangement using an array reader. The study shows that these proposed methods outperform the conventional methods in terms of BER and frame-error rate (FER) performances. Additionally, our findings also show that the proposed techniques were effective against media noise, which consisted of position and size variations. Furthermore, an MLP is the most effective approach to enhance system performance. Below, we summarize our contributions in this paper:  
* We propose a new array reader structure utilizing three readers, with the uppermost and lowermost readers positioned closer to the middle track to enhance data retrieval in a staggered BPMR system. * We propose to utilize an oversampling technique that can be implemented alongside the suggested array reader structure to obtain mutual data sequences from the middle track. * We then propose four techniques to enhance LLR by processing the obtained mutual data sequences. These techniques include hard-information flipping, maximum soft-information finding, bit-summation detection, and MLP application. * We present results from computer simulations that validate the performance and effectiveness of our proposed techniques. This validation demonstrates their ability to enhance the LLR of the desired track and highlights their potential advantages over existing approaches in terms of BER and FER performances. The remainder of this paper is organized as follows. Section 2 describes the staggered BPMR channel model. Section 3 explains the details of our proposed techniques. Section 4 reports the performance evaluation, and Section 5 concludes this work.