esa-sceva/satcom-chunk-collection huggingface dataset:
###### Abstract  
Flexure-based micro-motion mechanisms activated by piezoelectric actuators have a wide range of applications in modern precision industry, due to their inherent merits. However, system performance is negatively affected by model uncertainty, disturbance and uncertain nonlinearity, such as the cross-coupling effect and the hysteresis of the actuator. This paper presents an integrated learning-based optimal desired compensation adaptive robust control (LODCARC) methodology for a flexure-based parallel micro-motion manipulator. The proposed LODCARC optimizes the reference trajectory used in the desired compensation adaptive robust control (DCARC) by iterative learning control (ILC), which can greatly compensate for the effect of repetitive disturbance and uncertainty. The proposed control approach was tested on the flexure-based micro-motion manipulator, with the comparative results of high-speed tracking experiments verifying that the proposed LODCARC controller can achieve excellent tracking and contouring performances with parametric adaption and disturbance robustness. Furthermore, the iterative reference optimization can effectively accommodate the effects of unmodeled repetitive uncertainty from the micro-motion system. This study provides a practical and effective technique for the flexure-based micro-motion manipulator to achieve high-precision motion.  
flexure-based manipulator; precision micro-motion; desired compensation adaptive robust control; reference optimization
# Joint Timekeeping of Navigation Satellite Constellation with Inter-Satellite Links
## 4 Performance Evaluation of ISLT
### Inter-Satellite Clock Deviations  
The inter-satellite time comparison performance was analyzed with real ISL measurements of the 31 days. ISL relative clock deviations were calculated with Equation (16). The daily inter-satellite clock deviations were fitted with two-order polynomials to remove the initial clock deviations, frequency deviations and frequency drifts. The detrended clock deviations of pairs C27\(-\)C26 and C27\(-\)C37 are illustrated in Figure 3 as examples, which demonstrate the comparison precision was better than 0.2 ns (root mean square error: RMSE).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**PRN**} & \multicolumn{3}{c}{**Noise Diffusion Coefficients**} \\ \cline{2-4}  & \(\sigma_{1}\) **(s\({}^{1/2}\))** & \(\sigma_{2}\) **(s\({}^{-1/2}\))** & \(\sigma_{3}\) **(s\({}^{-3/2}\))** \\ \hline C19 & \(2.38\times 10^{-12}\) & \(5.66\times 10^{-16}\) & / 1 \\ C20 & \(3.42\times 10^{-12}\) & \(1.82\times 10^{-15}\) & / \\ C21 & \(3.02\times 10^{-12}\) & \(1.41\times 10^{-15}\) & / \\ C22 & \(2.68\times 10^{-12}\) & \(1.67\times 10^{-15}\) & / \\ C26 & \(2.50\times 10^{-12}\) & / & / \\ C27 & \(1.78\times 10^{-12}\) & / & / \\ C29 & \(1.70\times 10^{-12}\) & / & / \\ C30 & \(1.86\times 10^{-12}\) & / & / \\ C37 & \(5.05\times 10^{-12}\) & \(2.05\times 10^{-15}\) & / \\ \hline \hline \end{tabular}  
* \({}^{1}\) “/” means the noise is extremely small and not observed.  
\end{table}
Table 2: Noise diffusion coefficients of three BeiDou-3 satellites (passive hydrogen maser (PHM) indicated in italics).  
Figure 2: Allan deviations (ADEVs) of detrended clock deviations.  
By making difference between the MPOD clock deviations of a satellite pair, we were also able to get the inter-satellite relative clock deviations. The deterministic components were removed from the MPOD relative clock deviations. The noise characters of ISL and MPOD relative clock deviations were analyzed with Allan deviations, as shown in Figure 4. It should be noted that the noise of ISL clock deviations was filtered through a low pass filter, and the cycles per revolution were removed from MPOD clock deviations. According to the result, the noise characters of the two types of relative clock deviations were consistent.
# Deep Learning Semantic Segmentation for Water Level Estimation Using Surveillance Camera
## 2 Methodology
### Water Level Observation  
#### 2.5.1 Study Area  
A surveillance camera was installed at Paya Besar, Kuantan, Pahang with latitude and longitude coordinates of \(3^{\circ}47^{\prime}28^{\prime\prime}\) N and \(103^{\circ}14^{\prime}49^{\prime\prime}\) E, respectively (Figure 4). Images from five different days, from 3 January to 7 January 2021, were used to detect water body regions using one of the two semantic segmentation networks that demonstrate better performance than the other during the training. One image for each day was used so that the significant difference in river water levels could be shown from the results. In addition, the weather conditions during these periods were wet, where some days were raining heavily and some were not. Thus, the rising and falling of water levels can be demonstrated more clearly. Nonetheless, there is no water level sensor available in this area. Therefore, before applying the water level framework in this study, the framework was tested in another area with a water level sensor to validate the performance of the proposed work.
# Converging Telco-Grade Solutions 5G and beyond to Support Production in Industry 4.0
## 4 5G Functions and Features to Support the Information Flow within Industry 4.0
### Supervisory Control and Data Acquisition (SCADA)
Logistical task and processes within are often included in the Closed Loop Supply Chain (CLSC), Industrial Process Monitoring (IPM) and asset management. CLSC management is a big enabler in value-creating networks for sustainability. Due to several obstacles, CLSC implementation challenges, especially in an emerging manufacturing hub, are discussed in [147, 148, 149]. The evolution of IPM developments over time are briefly referred in [150, 151, 152, 153] with more focus on data-driven approaches. Asset Management includes factory equipment maintenance, which ensures that the equipment performs the necessary amount, at the desired standard, as safely as possible, and still meets the expected cost-effective lifetime [154, 155, 156]. The most important requirement regarding the aforementioned process is the (huge) number of nodes. Since the business world is constantly evolving, for more confident decisions, dynamic environments, full of uncertainties, complexities, and ambiguities, require precise cooperation [157, 158, 131]. Industrial networks comprise a broad range of devices such as sensors, PLCs, or HMI, which ultimately collect real-time production chain data and then issue control commands to remotely control the entire operation [159, 160, 161]. In contrast to the previous process, are co-operate driving, remote control, traffic management and safety features, and considered classic automation tasks. One of the main technologies that enable vehicles to be powered in a cooperative manner to attain system-wide benefits is cooperative longitudinal motion control [162, 163]; meanwhile, Video over remote control sends data to data processing systems from systems that track and control the physical environment, in which cloud computing has proven to have powerful resources to meet processing requirements [164, 165]. The paper [166, 167, 168] introduces an engineering proposal for techniques to model typical sources of traffic to be found in industrial networks. The studies in [169, 170] investigate the link between industrial robot adoption and workplace injuries using safety panel data used in manufacturing industries. Augmented Reality (AR) is a mechanism in which the real or the physical world is augmented by computerized knowledge. This allows us to better understand the method of various (complex) physical-world tasks. There are various papers [171, 172, 173, 174] that have assessed the impact of Augmented Reality (AR) and its usability through systematic literature reviews of actual industrial processes. The development of an open source controller interface for Industry 4.0 based on RAMI 4.0 and OPC UA protocol is described in [143, 144, 145, 146]. The typical requirements of such tasks involve real-time operation and mobility management that is able to handle the objects moving up to 50 kmph.
# High-Gain Multi-Band Koch Fractal FSS Antenna for Sub-6 GHz Applications
## 3 Results and Discussion
### Parametric Investigations
#### 3.1.3 Antenna Miniaturization  
The primary substrate size of the designed antenna was equal to 47.92 mm \(\times\) 46.15 mm \(\{\rm W_{S}\times L_{S}=4a_{e}\times(L_{E}+3a_{e})\}\). In this case, the antenna achieves a gain of 15.11 dBi at 3.5 GHz with tri-band performance. The antenna results in a wide sub-6 GHz bandwidth that covers the n77, n78, and partial n79 bands. After this, the ground width is reduced to three times the effective radius of the patch, i.e., 3a\({}_{e}\) = 35.94 mm. This ground size reduces the antenna size to 35.94 mm \(\times\) 46.15 mm. This size miniaturization gives rise to an improvement in the antenna gain to 4.82 dBi, but it results in a decreased antenna bandwidth in the first band and tunes the antenna at 3.44 GHz, i.e., closest to the design frequency of 3.5 GHz. Further, the antenna width is reduced to 2a\({}_{e}\) = 23.96 mm, without beneficial results in favor of the sub-6 GHz FR-1 frequency band and covering only the n78 band. Therefore, the antenna width is selected as 3a\({}_{e}\), and further reduction is carried out on the antenna substrate length, which is equal to \(L_{E}+2a_{e}+3h=38.97\) mm. This miniaturization results in the proposed antenna with an overall 36.67% degree of miniaturization in the substrate requirement for antenna fabrication as compared to the conventional circular antenna's size (4a\({}_{e}\)\(\times\) 4a\({}_{e}\) = 47.92 mm \(\times\) 47.92 mm). This reduction in the antenna's width and length will result in the first resonating frequency at 3.44 GHz, with an improved lower band bandwidth and a reduction in gain to 9.37 dBi. All reflection coefficients of the miniaturization process are shown in Figure 10, and their performance parameters are provided in Table 4. Therefore, it is required to improve the reduced values of the gain and bandwidth due to the miniaturization process by introducing a frequency-selective surface below the main antenna radiator.
# Power Quality Issues and Mitigation for Electric Grids with Wind Power Penetration
## 3 PQ Mitigation Techniques
### Traditional Methods
#### Dynamic Voltage Restorer  
Reactive power uncompensation is one of the most harmful PQ issues that cause voltage deviation at PCC. DVR is the solution for series compensation. Its function is to inject voltage to keep the voltage of the WTGs within the acceptable level. The system injected dynamic voltage is controlled to remove any fluctuations of the voltage. Besides maintaining the voltage level, DVR can reduce transients in voltage and limit fault current [21]. An example is given in Ref. [32] which investigates the effect of connecting DVR to a WTG-driven DFIG to allow uninterruptible fault ride-through of voltage dipsfulfilling the grid code requirements. The system performance exercises a two-phase 37% voltage dip of 100 milliseconds duration. When the DVR compensation is applied, the voltage dip can be almost compensated, and the DFIG WTG can continue nominal operation as required by grid codes. Further, a symmetrical 30% grid voltage swell of 200 milliseconds duration is examined. As the voltage swell occurs at t = 0.8 s, the DVR injects back a voltage swell of the same but negative magnitude into the system. Hence, the voltage at DFIG WTG is reduced to the rated voltage while the grid swell is cleared at t = 1 s [21].
# Frequency Selective Surfaces: Design, Analysis, and Applications
## 2 Applications of FSSs
### FSS in Wireless Communications
#### 2.3.3 Enhancing Front-to-Back Gain  
The front-to-back ratio (F/B) is the ratio of the power radiated in the forward direction (main lobe) to the power radiated in the opposite direction (back lobe). This metric is crucial for ensuring that most of the radiated power is concentrated in the desired direction, minimizing energy loss [107]. Using FSSs, particularly with multi-layer configurations, can substantially increase the front-to-back gain by manipulating the reflection and transmission properties of the surface elements [108].  
For example, studies have shown that by utilizing multi-layer FSS with fractal and hexagonal elements, the front-to-back gain can be increased by up to 10 dB, enhancing the directivity and efficiency of the antenna [109]. This is achieved by carefully tuning the reflection phase of the FSS elements, which reduces back radiation and concentrates more power in the forward direction.
## 3 Results and Discussion
### Cell Viability Assay  
The possible cytotoxic activity of the citrus extract on the U87 and LN18 glioma cell lines was evaluated by MTT assay at 48 h with different concentrations (0.5, 1, 5, 10, 20, 40, 80, 100, 150, 200, and 400 \(\upmu\)g/mL). The MTT assay results demonstrated that the citrus extract did not exhibit cytotoxic effects on U87 or LN18 glioma cell lines across the tested concentration range (0.5 to 400 \(\upmu\)g/mL). In fact, the viability of U87 cells treated with citrus peel extract at concentrations ranging from 0.5 to 400 \(\upmu\)g/mL remained above 70%, indicating non-cytotoxicity (Figure 2). Similarly, the viability of LN18 cells treated with the citrus extract at the same concentration range remained above 90%, confirming the non-cytotoxicity (Figure 3). These findings suggest that the citrus peel extract was safe for these cell lines at the tested concentrations and time point (Figure 3).
# Enhancements and Challenges in CoAP--A Survey
## 3 Applications of CoAP
### Security
#### 3.2.2 Authentication and Access Control  
[PERSON] et al. propose a CoAP-based authentication and access control framework for IoT in [15]. A low power security framework is proposed for main server and per service-based fine grain access control is implemented. CoAP is implemented to provide communication with packets with low overhead for the IoT environment. The scheme employs authentication and access control schemes such as Kerberos with CoAP and optimized ECDSA is issued for encryption and privacy. Ticket generation-based solution is provided for authentication and accessing services. The client is issued a valid ticket for authentication upon registration, which is then used for gaining access control while requesting a particular service from main server.
# Can Biochar Improve the Sustainability of Animal Production?
## 2 Summary of Biochar-Production Techniques
### Properties of Biochar  
Regardless of the mode of synthesis, the physical and chemical properties of biochars play a great role in the performance of biochar in various applications, including adsorption, catalysis, soil conditioning, bulking agent, and bedding material in animal agriculture. Some of the key properties are presented below.
# Cost-Effective Design Modification of a Sleeve Bearing with Large Bearing Clearance
## 2 Experimentation  
A 45 MW Kaplan hydropower machine was oriented vertically and supported by three bearings, i.e., an upper generator guide bearing (UGB), a lower generator guide bearing (LGB), and a turbine guide bearing (TB). The UGB and original LGB were sleeve bearings, whereas the modified LGB and TB were a four-lobe bearing and a 12-shoe tilting-pad journal bearing (TPJB), respectively. A schematic diagram of the hydropower machine and some technical details of the system are presented in Figure 2 and Table 1, respectively.  
On-site vibration measurement was performed before and after the design modification employed on the LGB. Two sets of measurements were carried out on the machine with the original LGB (MOB) and modified LGB (MMB). In the first case, the original LGB, which was a sleeve bearing with \(C_{b}=1.6\) mm, was installed, whereas in the second case, the original LGB was modified to a four-lobe bearing with \(C_{b}=0.45\) mm.  
Inductive sensors were installed at the three bearing locations to measure the shaft and bearing housing lateral displacements in the \(x\) and \(y\) axes. During the measurement, the rotor ran at a nominal speed (\(\Omega_{0}=150\) rpm), and measurements were carried out for different load cases. The data were sampled at 600 Hz, and each measurement was carried out for 30 s.  
\begin{table}
\begin{tabular}{l c c c} \hline
**Description (Unit)** & **Exciter** & **Generator** & **Runner** \\ \hline Mass (kg) & 3500 & \(1.51\times 10^{5}\) & 53,600 \\ \hline Polar moment of inertia (kg\(\cdot\)m\({}^{2}\)) & 3500 & \(1.38\times 10^{6}\) & 56,400 \\ \hline Diametral moment of inertia (kg\(\cdot\)m\({}^{2}\)) & 1750 & \(6.88\times 10^{5}\) & 44,300 \\ \hline Unbalanced magnetic pull (MN/m) & 26.62 & 170 & \\ \hline Young’s modulus (N/m\({}^{2}\)) & & \(2\times 10^{11}\) & \\ \hline \end{tabular}
\end{table}
Table 1: Specifications and parameters of the hydropower unit.  
Figure 1: Refurbishment of the hydropower unit: (**a**) generator hall; (**b**) a technician conducting service in the confined space between the generator and LGB; (**c**) a small segment of the modified LGB, showing the axial groove and the two consecutive lobes.
# Optimizing Crosstalk in Optical NoC through Heuristic Fusion Mapping
## 2 Design of Heuristic Fusion Mapping Algorithm for Crosstalk Optimization
It can be seen from the figure that the speed value of task 1 is \"+2\", so the position moves two grids to the right to reach topology node 3; the speed value of task 2 is \"+1\", and movesone1 grid to the right, but the topology node has been occupied by task 1, so task 2 continues to move to the right until the empty topology node 4 is found. The speed value of task 3 is \"-3\", which moves three spaces to the left, but causes the boundary crossing, so the modulus reaches the position of topology node 9. The rest of the tasks are moved according to this rule. After nine moves, they become the mapping situation corresponding to step 9 in the figure. After the particle swarm optimization algorithm generates the optimal solution, simulated annealing is needed to prevent it from falling into the local minimum. In the implementation, two tasks in the random exchange mapping solution are used to avoid the local optimal solution, which is similar to the gene mutation mode in the genetic algorithm. Figure 4 shows this process. On the basis of the optimal particle mapping solution, task 5 and task 9 are exchanged, and the network crosstalk value is calculated for the adjusted mapping solution. If the crosstalk is better than that of the original optimal particle mapping, then the mapping method is regarded as the optimal mapping. Otherwise, the adjusted mapping is considered as a vicious solution and accepted with a certain probability. In 1953, Metropolis proposed the Metropolis criterion, in which new states are accepted with certain probability. The probability of modifying the optimal mapping scheme is shown in Equation (5). \[\mathrm{P(i\to j)}=\left\{ \begin{array}{c}1,\,\mathrm{f(i)}<\mathrm{f(j)}\\ \mathrm{e}^{-\frac{\mathrm{f(i)}-\mathrm{f(j)}}{\mathrm{t}}},\,\mathrm{f(i)} \geq\mathrm{f(j)}\end{array} \right. \tag{5}\]  
where f(i) and f(j) are the objective function values corresponding to i and j; and t is the temperature control parameter. The initial temperature t is 3000, and the temperature decreasing rate is 0.98. When solving the maximum value, if the function value f(j), corresponding to the current solution j, is greater than the function value f(i), corresponding to the previous solution i, the new solution i will be accepted directly; otherwise, the new solution will be accepted with a certain probability.
## 2 Message Replication in OppNets for Sensed Data Collection
### Impact of High Node Population
For instance, high encounter frequencies during rush hours may cause messages generated within the period to be over-replicated, while messages generated before or afterwards may be under-replicated, cf. Figure 7 (two peaks occur every 24 h which correspond to periods of increased encounter frequencies such as during rush hours). Similarly, Gossiping and the time threshold approach require more adaptive parameters, i.e., \(p\) and the time threshold, respectively. [PERSON] and [PERSON] [57] and [PERSON] et al. [58] also require an adaptive reference value and TTL threshold, respectively. Due to increased network dynamicity in higher node population, values that may be optimal under one network condition may not be suitable under another. Hence, distributed mechanisms that can enable them to adapt to different network conditions are required. Figure 6: PRoPHET’s throughput (in %) without summary vector exchange and with summary vector exchange in the small scenario.
## 3 Results and Discussion
### Evaluation of Antioxidant Activity  
The results of the antioxidant and antiradical assays for the EO from Tunisian _T. luteum_ subsp. _flavovirens_ are reported in Table 2.  
Overall, the EO exerted significant antioxidant activity in both the DPPH and \(\beta\)-carotene bleaching assays and was more effective than the lipophilic BHT. However, if compared to the polar reference compound, i.e., ascorbic acid, the antioxidant activity of the EO held modest results. These results are in partial agreement with what has been previously observed by other authors for the EO of the same plant species from Morocco [21]. In this work, the authors reported the efficacy of the EO in reducing the free radical DPPH, which was significantly higher than BHT and comparable to ascorbic acid. Conversely, the EO was not active in the \(\beta\)-carotene bleaching assay. In the same work, the authors associated the antioxidant effects of the EO with its content in some monoterpenoids, such as elemol, \(\alpha\)- and \(\beta\)-pinene, trans-caryophyllene, \(\alpha\)-humulene, and \(\gamma\)-eudesmol, and/or synergistic effects between all of the compounds [21]. Considering that the EO from Tunisian _T. luteum_ subsp. _flavovirens_ presents a high abundance of monoterpenoids and shares several of these constituents, we can propose a similar correlation between the chemical content of the EO and its antioxidant properties.  
The antioxidant properties of the EOs of several members of the genus _Teucrium_ have been extensively reported in the literature and are exhaustively reviewed in [36]. The studies are mostly concerned with the use of the DPPH radical scavenging test. Nevertheless, what emerges from the revision of this mole of data is the lack of specific molecular markers associated with the antioxidant activity of _Teucrium_ EO. Although several authors have attempted to correlate specific constituents (e.g., \(\beta\)-caryophyllene, dolichodial, phenols, allylic alcohols, and unsaturated hydrocarbons) with bioactivity, the synergism among all of the constituents is usually purported to be responsible for the antioxidant effects [36], although further studies are needed for confirmation.