esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Application Examples
### Vertical Deep-Well Grounding Electrode Partially Corroded  
From numerous measurements, it has been proven that the deep-well grounding technology has a smaller grounding resistance and a lower step voltage, while the area assigned to the installation is small and when in the lowest layer deep in the soil, where the vertical electrode is located, the resistivity is low [13]. In this example, a deep-well grounding electrode made of stainless steel rods with a 9 mm radius and 150 m long is driven into a fictitious horizontally three-layered soil with resistivities \(\rho_{1}=100\)\(\Omega\)m thickness \(h_{1}=4\) m, \(\rho_{2}=200\)\(\Omega\)m thickness \(h_{2}=6\) m, and \(\rho_{3}=50\)\(\Omega\)m. A part of the electrode located in the soil bottom layer, is covered with an oxide film of thickness \(e=2\) mm and resistivity  
Figure 10: Some electrical features of the ideal electrode (**upper** panels) and those of the partially covered resistive electrode (**lower** panels).  
Figure 9: Ground Potential Rise contour plot from the grounding electrode of the transmission line tower in Figure 8.  
\(\rho_{ox}=720\)\(\Omega\)m. Once again, the oxide layer resistivity and thickness are fictitious for the purpose of assessing the effect on grounding resistance and other parameters. As already commented in Section 2, the CEER can still be applied if the oxidized part is entirely located in a soil layer. Due to the nature of the electrode, the potential at the ground surface will not present significant differences between the two electrode configurations considered, that is, as PEC and with real attributes. While it is to be expected that the grounding resistance will present appreciable differences, after dividing the rod into segments at a rate of three segments per meter, an electric current of 1 A is injected through its upper end, and the nodal potentials are calculated, especially the one associated with the input node of the current, in order to calculate the grounding resistance. The results of the application of the proposed model are summarized in Table 1.  
Table 1 clearly shows the influence of the two electrode conditions that are studied in this paper. The difference between completely ignoring the internal resistance of the electrode and taking the value of the resistivity of the copper instead impacts the grounding resistance by less than 1%. However, if copper is replaced by a material such as stainless steel, the difference rises to almost 21% if oxidation is not taken into account and up to 26% when including the effect of oxidation. As already mentioned in some of the previous examples, the effect of the internal resistance of the conductors intensifies with the size of the electrode. This example shows that the advantages of a long electrode driven into the ground are attenuated by the need to use materials other than copper with which to build the grounding electrodes.
# Design of Magnetic Concrete for Inductive Power Transfer System in Rail Applications
## 3 Materials and Methods
### Electromagnetic-Thermal Simulation in IPT Systems
The thermal properties of each IPT component--including Litz wire, ferrite, magnetic concrete, and normal concrete--are summarized in Table 2. The initial temperature, typically representing the ambient or starting temperature, is also defined. Next, an electromagnetic simulation is performed to calculate power losses within various system components, with a particular focus on materials such as Litz wire, ferrite cores, and magnetic concrete. These calculated losses are then applied as heat sources in the thermal simulation, which determines the resulting temperature distribution across the system. This process is iterative. Temperature input data are then updated, and simulations are rerun until thermal equilibrium is reached. It should be cautioned that the current study only considers the losses from the Litz wire, ferrite cores, and magnetic concrete. Additional losses from the power of electronics may also occur. \begin{table}
\begin{tabular}{l l l} \hline \hline
**Component** & **Material** &
\begin{tabular}{l} **Thermal Conductivity,** \\ **W/m\({}^{\circ}\)C** \\ \end{tabular} \\ \hline Coil & Copper [28] & 385 \\ Receiver Cores & Ferrite [42] & 4 \\ Transmitter Coil Base (CD1) & Ferrite & 4 \\ Transmitter Coil Base (CD2) & Magnetic Concrete & 3.6 \\ Transmitter Coil Base (CD3) & Normal Concrete [63] & 2.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Thermal properties of each IPT component. Figure 7: Iterative electromagnetic–thermal simulation workflow. By incorporating magnetic concrete into these simulations, the model provides insights into heat distribution and potential thermal stresses, thereby supporting enhanced system design and optimized thermal management strategies.
# Smart Grid Fault Mitigation and Cybersecurity with Wide-Area Measurement Systems: A Review
## 1 Introduction
### Search Strategies and Selection  
In this review, papers were selected that focus on WAMS development and its potential application to power system networks. Keywords like \"WAMS\", \"Wide-Area Protection Systems\", \"PMU deployment\", and \"Systems for control of Wide-Area Power Systems\" were used to search databases like ScienceDirect and Web of Science to select recent, well-cited research studies that cover the major variants of WAMS technologies and innovations. Papers with more focus on cybersecurity and power system optimization were prioritized.
# Combined Use of 3D and HSI for the Classification of Printed Circuit Board Components
## 2 Materials and Methods
### Data Set Acquisition  
The measurement setup shown in Figure 2 consists of two Specim Ltd. (Oulu, Finland) hyperspectral pushbroom cameras (Specim FX10 and Specim FX17), a 3D scanner, a linear stage and an illumination unit. This system was chosen for the acquisition of real electronic waste samples consisting of plastics and PCBs from the landfill. Accordingly, these objects are damaged and dirty. Special attention was paid to the choice of PCBs with different mounted electronic components. The required wavelength is limited to the NIR range, therefore only the Specim FX17, working in the range from 900 nm to 1700 nm (224 bands), is used for the measurements in this work. Acquired datasets are radiometrically normalized by using dark reference image for dark-current (closed shutter) and a white reference image to reduce the influence of the intensity variability. For the white calibration a 99% reflectance tile was used.  
For the acquisition of the geometry, a structured light scanner from COM GmbH (Braunschweig, Germany) is used. The Atos Core 500 is a high-resolution optical system with a maximum resolution of 0.195 mm and a depth accuracy of 0.05 mm. This 3D scanner consists of two stereoscopic cameras with 5-megapixel resolution and a blue LED light projector which projects structured light onto the object. The projected light, which essentially encodes the surface of the object, is captured by the cameras and triangulation is used to obtain the necessary 3D information.
# A Haar Wavelet Decision Feedback Channel Estimation Method in OFDM Systems
## 6 Conclusions and Future Work  
This paper proposes a Haar wavelet decision feedback channel estimation method. The DF channel estimation method can provide high data transmission rate and spectrum efficiency while the wavelet decomposition can suppress the AWGN existing at the estimated channel coefficients in time-domain effectively. Simulation results have verified that combining these two methods can provide good performance under static slight frequency-selectivity CDT1 channel. But under the conditions of strong frequency-selectivity and dynamic channels, the proposed Haar wavelet method needs improvement to further improve the accuracy of channel estimation.  
Compared with the conventional DF channel estimation method, the proposed Haar wavelet method has better performance. Compared with the LS and DFT channel estimation methods, the proposed Haar wavelet method not only has better performance but also has high data transmission rate and spectrum efficiency. With the improvement of the fifth generation (5G) technology, there are more demands for high transmission data rate and spectrum efficiency in communication systems. Hence, the proposed Haar wavelet channel estimation method has broad market prospect and can be applied in optical communication, radar communication, and underwater acoustic communication [5].  
In future work, we will do some significant researches on the following aspects. First, we will apply the Haar wavelet method in Turbo coded CP-OFDM system [7; 8] to better adapt to the strong frequency-selective and dynamic channels. Second, we will make a meaningful study about the application of other wavelets in channel estimation.  
[PERSON] and [PERSON] conceived the algorithm and designed the experiments; [PERSON] performed the experiments; [PERSON] and [PERSON] analyzed the results; [PERSON] drafted the manuscript; [PERSON], [PERSON], and [PERSON] revised the manuscript. All authors read and approved the final manuscript.  
This work was supported by the National Natural Science Foundation of China (No. 61702303) and the Natural Science Foundation of Shandong Province, China (No. ZR2017 MF020, No. ZR2015 PF004).  
The authors declare no conflict of interest.  
Figure 11: BER performance with QPSK modulated CP-OFDM and wavelet-OFDM systems under CDT6 channel with Doppler spread 20 Hz.
###### Abstract  
The Internet of Things uses low-power wireless communication for wireless connectivity and efficient energy. Low-power wireless communication is applied to IoT for wireless connection and efficient energy consumption in various areas such as wearable devices, smart homes, and power plants in order to send and receive data and control the environment. Security is becoming more important because the Internet of Things controls real physical systems. For the security of the Internet of Things, the encryption key is important to identify and authenticate devices that are trusted. The static encryption key method used for devices is likely to be calculated in reverse through the value of the key and is vulnerable to exploitation attacks. This requires the application of dynamic encryption keys that generate keys periodically. However, in the case of low-power wireless communication, the asynchronous communication method and the packet loss make it difficult to apply existing dynamic encryption key technologies. In this paper, we proposed dynamic encryption key method that applies the mechanism of the block chain to solve these problems. Based on the history of sensor data between devices, encryption keys are dynamically generated. The proposed method is to generate the same encryption key between devices with only one step of asynchronous communication considering packet loss. The proposed method is also validated in terms of availability and security in the Internet of Things low-power wireless communication.  
blockchain; Internet of Things; dynamic encryption key; IoT device security; low power wireless communication; Bluetooth low energy +
Footnote †: journal: Applied Soft. 2020, 10, 7940; doi:10.3390/app10217940
# An Efficient Local Search Heuristic for Earth Observation Satellite Integrated Scheduling
## 6 Conclusions  
In this paper, we study the earth observation satellite integrated scheduling problem (EOSIS) which considers the imaging activity and data transmission activity integratively. This is a realistic problem and includes complicated constraints. We develop an integer linear programming model to formulate the problem. With this model, we used CPLEX to solve the problem, and the results show that CPLEX is only able to solve a small-sized problem.  
Due to the complexity of the problem, we propose an efficient local search heuristic algorithm (ELSH) to solve instances of large size. The proposed ELSH is characterized by an efficient constraint handling mechanism to improve algorithm speed and a dedicated improvement-perturbation procedure to guarantee the quality of results.  
Experiments were conducted to illustrate the excellent performance of the proposed ELSH. In particular, it is able to achieve optimal solution quickly for small instances with less than 50 targets and two satellites, and dominates the state-of-the-art algorithm on large instances with up to 2000 targets.  
For future work, we would like to investigate more problem-tailored heuristics and further improve the performance of the algorithm.  
Writing, Y.C. and J.O.; original draft preparation, Y.C.; methodology, Y.C.; software, J.L.; data curation, J.L.; development formal analysis and supervision, R.H.; review and editing, J.O. All authors have read and agreed to the published version of the manuscript.  
This work is partially supported by the National Natural Science Foundation of China, Grant No. 71701203 and the National Natural Science Foundation of Hunan Province, Grant No. 2018J3618.  
The authors thank the editor and the anonymous reviewers for their very helpful and constructive comments.  
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the works reported in this paper.
# Analysis of Vehicle-Bridge Coupling Vibration Characteristics of Curved Girder Bridges
## 2 Vehicle-Bridge Coupled Vibration of Curved Girder Bridges  
In the finite element analysis (FEA) of curved girder bridges, the curved beam element, the straight beam element, the mass point element, and the spring element can be selected to discretize the bridge structure [16; 17; 18]. By calculating the kinetic and potential energies of each unit and structure, the vibration equation of the bridge structure is derived through Hamilton's principle. In the standard FEA of curved girder bridges [19; 20; 21], structures must first be discretized as a series of spatial curved beam units, straight beam units, mass point units, spring units, or combinations of multiple units. Then, taking the equilibrium state of the bridge structure under self-weight as the initial state, according to the finite element theory, the unit characteristics analysis is performed, calculating each unit's stiffness matrix, mass matrix, and equivalent node load array.  
Establishing a vehicle dynamic analysis model and its vibration equation is the foundation for analyzing the coupled vibration of curved girder bridges and vehicles. Considering the vehicle as a multi-rigid-body model connected by springs and dampers can accurately reflect the vehicle's mass, stiffness, and damping characteristics. Under the assumption of small deformation, by calculating the virtual work made by the vehicle's inertial force, elastic force, damping force, and external load, the equations of the vehicle vibration were established on the basis of the principle of virtual work.
## 4 Discussion
### Orowan Bypass-Like Strengthening Mechanism in Architected Metamaterials
#### Influence of Volume Fraction of Meta-Precipitates  
There are several factors that affect the strengthening of precipitation, such as volume fraction of the precipitates, strain rate, temperature, and the coherency between precipitates and matrix [47]. Here we discuss the influence of volume fraction of meta-precipitates on the strength of architected metamaterials, to further illustrates that the strengthening mechanism similar to precipitation hardening is applicable to architected metamaterials.  
In precipitation hardening, the relationship between the increase of yield stress \(\Delta\tau_{y}\) and the particle spacing of precipitates \(L\) can be expressed by the Orowan Equation (3) [48]:  
\[\Delta\tau_{y}=G\mathbf{b}/L \tag{3}\]  
where \(G\) is the shear modulus of the matrix and \(\mathbf{b}\) is the Burgers vector.  
The relationship illustrates that a higher volume fraction of the precipitates leads to a reduced spacing and a significant increase in yield stress. In architected metamaterials embedded with meta-precipitates, the yield stress (compressive strength) is also in a positive correlation to the volume fraction of the meta-precipitates. The increase of volume fraction also leads to a higher plateau stress and an improved energy absorption ability.
# CANPerFL: Improve In-Vehicle Intrusion Detection Performance by Sharing Knowledge
###### Abstract  
The Controller Area Network (CAN) is a widely used communication protocol in automobiles, but it is vulnerable to various types of attacks. To address this issue, researchers have been exploring the use of intrusion detection systems (IDS) for the CAN bus. Deep learning and machine learning have been proven to be powerful tools for detecting intrusions accurately and quickly. However, deep learning models require large amounts of data to achieve optimal performance, which can be challenging in the case of a CAN bus IDS. To overcome this challenge, we propose a novel machine learning-based IDS called CANPerFL that uses a personalized federated learning scheme to aggregate datasets from different car models. By building a universal model trained on a small amount of data from each manufacturer, we can provide global knowledge that can be transferred to improve the performance of each participant. To demonstrate the efficiency of the proposed model, we collected a real CAN dataset consisting of three different car models: KIA, BMW, and Tesla. The experimental results show that the proposed model increases F1 scores by 4% overall, compared to baselines. Moreover, the proposed system provides significant advantages when the local dataset of each participant is relatively small. According to our experiments, the proposed models can achieve F1 scores of more than 90% with at least 30k training samples on each client. Finally, we show empirically that each participant takes benefits from joining the CANPerFL system.  
controller area networks; in-vehicle networks; injection attacks; intrusion detection system; personalized federated learning +
Footnote †: journal: Applied Sciences  
1
# Implementation of a Topology Independent MAC (TiMAC) Policy on a Low-Cost IoT System
## 2 Past Related Work
In the same spirit, the authors in [29] introduce a distributed TDMA scheduling algorithm based on exponential backoff rule, the nodes' residual energy, and the number of neighbors. All works given above regarding TDMA policies in IoT are some of the newest in the literature (i.e., 2015-2020). Interestingly, in the works referenced above, there are two similarities in all of them: (i) All of the policies and algorithms proposed have been tested on simulators, rather than on real devices; and (ii) synchronization of nodes is not the case in any of them. At the same time, in most, it is either assumed that GPS infrastructure is used by the nodes (thus synchronization is achieved through them), or centralized approaches are assumed. As a result, there is no knowledge on how these approaches would work on low-cost systems, where fewer options are available (e.g., no GPS can be implemented due to its high cost). The current work is based on deploying a known policy (TiMAC) on a low-cost IoT system. In addition, considering the drawbacks of the low-cost system (further explained later), a decentralized approach for the synchronization of nodes in such systems is given. TiMAC was firstly introduced by [PERSON] and [PERSON] in [17] and it has been further extended and implemented in various applications. For example, the authors [11] consider TiMAC in their paper for vehicular networks, while they also extend TiMAC to one that considers disjoint frames depending on the vehicle's direction of movement.
# Enhancement of Feed Source through Three Dimensional Printing
## 4 Result and Discussion  
We used CST-Microwave Studio to calculate the various performance criteria of the WBP structure. The noted VSWR is less than 2 from 10 GHz to 15 GHz of the operating frequency band that signifies wideband operation. The experimental setup was carried out in an NSI-700S-50 spherical near field measurement system at the Australian Antenna Measurement Facility, which is shown in Figure 7. The figures attached show the fabricated WBP structure and the overall assembled system with the feed source. Further sections detail radiation patterns and characteristic plots. Figure 7(a) signifies the performance matrices of the overall system with and without WBP structure. The overall improvement of 2.5 dBi in broadside directivity and gain were noted throughout the operating frequency range. This highlights the fact that the performance of the horn can be enhanced by compromising its aperture dimension and with the use of the proposed 3D printed WBP structure. The voltage standing wave ratio (VSWR) is shown in Figure 7(b), depicting the wideband performance of the overall system. VSWR values are less than 2.2 over the operating frequency range. Measured VSWR depicts the matching condition of the proposed WBP structure. Similarly, the S11 plot, as shown in Figure 7(c), shows the wideband characteristics of the proposed system where S11 values are less than \(-10\) dB over the operating frequency band from 10 to 15 GHz. The simulated and measured values with and without the proposed prototype show better S11 values in the Ku-band of the operating frequency range. Table 3 shows an improvement in measured directivity and gain values after the placement of the proposed WBP structure above the feed source. Those values are compared against the simulated results. As noticed, in a design frequency of 12 GHz, simulated directivity, gain, and measured directivity, gain for the horn-only case are 20.489, 20.463,  
Figure 6: Planar wave fronts observed above WBP (**a**) 10 GHz (**b**) 11 GHz (**c**) 12 GHz (**d**) 13 GHz (**e**) 14 GHz (**f**) 15 GHz. Figure 7: Measurement system showing the experimental setup of proposed wideband prototype. 20.310, 20.335 dBi, which are improved by around 2.5 dBi resulting in a simulated directivity, gain and measured directivity, and gain with the proposed prototype of 22.1, 21.9, 23.372, and 23.007 dBi, respectively. Throughout the operating frequency band, the overall performances in the directivity and gain margins are improved. Figure 8: (a) Simulated and measured broadside directivity and gain plots. (b) Simulated and measured VSWR over 10 to 15 GHz frequency range. (c) Simulated and measured S11 parameter over 10 to 15 GHz frequency range.
## 4 Analysis of Modeling Efficiency  
To further validate the effectiveness of the iterative acceleration scheme based on the Lorenz-Mie theory, the computational efficiency of the improved model is investigated as well. In those simulations, the light wavelength is set as 0.5 \(\upmu\)m, and the scatterers are set as spheroidal particles with different shapes. All the scattering processes are simulated on the same computer (32 bit 3.1 GHz), and the computational time of the traditional and improved IIM T-Matrix code is presented in Table 4.  
Figure 8: The scattering phase matrix obtained by the IIM T-Matrix method and Multi-Resolution Time Domain (MRTD) for hexagonal prism.  
As can been seen, after being improved by the iterative acceleration scheme, the computational efficiency of the IIM T-Matrix method is improved notably, where for the particle with (a, b) = (1.5, 2.0), the computational time is cut down by 75%. With the increase of the aspect ratio (a/b), the improvement of the computational efficiency is much more remarkable.