esa-sceva/satcom-chunk-collection huggingface dataset:
# Fault Diagnosis of Rotating Electrical Machines Using Multi-Label Classification
## 3 System Description and Experiment
### Feature Extraction and Dataset Preparation for Training
Fifteen different samples are generated with random contaminating frequencies for all of the fault-free, multiple-fault, and single fault (unbalance or misalignment) cases and additionally the data collected by the accelerometers at both sides for the severity evaluation. The training set consists of 64 feature vectors, including the original ones and each of them containing 27 features. In our qualitative models _'isUnbalance'_ and _'isMisalignment'_ (Table 2) are the fault label columns which consist of values 0 (No) and 1 (Yes) corresponding to the presence of the symptom of a fault in a given sample. For the fault severity classifier, we have specified the labels according to the previously presented ISO standard [25] as _'Good'_, _'Satisfactory'_, _'Unsatisfactory'_, _'Unacceptable'_. The dataset is divided into a training set 70% of the vectors to train the classifier and a testing set of 15 % and 15% for validating the accuracy of the classifier on new data. When most of the samples have the same labels in the training set, the classifier will achieve a high accuracy value. In order to avoid such a bias,  
Figure 6: Multitaper power spectral density estimation of generator current signal for fault frequency magnitude detection. half of the dataset composed of samples including the fault features. Further metrics are applied for the proper evaluation of the performance.
###### Abstract  
This paper presents a photoacoustic non-destructive evaluation (pNDE) system with an ultrahigh resolution for the detection of multi-scale damage in carbon fiber-reinforced plastic (CFRP) composites. The pNDE system consists of three main components: a picosecond pulsed laser-based ultrasonic actuator, an ultrasound receiver, and a data acquisition/computing subsystem. During the operation, high-frequency ultrasound is generated by pulsed laser and recorded by an ultrasound receiver. By implementing a two-dimensional back projection algorithm, pNDE images can be reconstructed from the recorded ultrasound signals to represent the embedded damage. Both potential macroscopic and microscopic damages, such as surface notches and delamination in CFRP, can be identified by examining the reconstructed pNDE images. Three ultrasonic presentation modes including A-scan, B-scan, and C-scan are employed to analyze the recorded signals for the representation of the detected micro-scale damage in two-dimensional and three-dimensional images with a high spatial resolution of up to 60 \(\upmu\)m. Macro-scale delamination and transverse pJ cracks are clearly visualized, identifying the edges of the damaged area. The results of the study demonstrate that the developed pNDE system provides a non-destructive and robust approach for multi-scale damage detection in composite materials.  
composites; multi-scale; embedded damage; non-destructive testing; photoacoustic; ultrasonic representation +
Footnote †: journal: Applied Sciences
## 4 Discussion and Conclusions
### Communication  
Low frequency communications conducted using relatively large inductor loops have shown that communication through water, soil, plastic and air are possible. The range has been shown to be of the order of a few metres using simple equipment and this can be improved with the appropriate use of amplifiers and coil design. The main issue with this method is the size of the coils (which is proportional to the frequency used) required to produce a significant signal; however, it has been shown that a coil of the same diameter as the pipe is sufficient for communication along the pipe through water for a considerable range.  
Figure 18: The effect the coil diameter has on the resonant frequency and reflection coefficient (related to signal strength) for a range of simple oscillating circuits.  
Attenuation of signals increases with frequency, limiting the range of high frequency communications considerably. It has been shown that a signal can still be detected over a couple of metres in water and soil, but the complexity of the circuit required to achieve this is significantly higher than necessary for low frequency communications. If used in air to perhaps communicate between Smart Servers, high frequency communications fair far better and can be used to transmit over a greater distance than low frequency methods using common commercial devices such as Bluetooth.
## 3 Case Studies of Pilot and Full-Scale STRBs
### Water Works Sludge (England)
#### 3.4.4. Infiltration Rate  
Most of the water content in each sludge load drains vertically through the residual sludge layer and the filter media and reaches the drainage network. The water flow curve is a useful parameter that should be monitored during the STRB operation (Figure 13). A decrease in the peak flow (L/s/m\({}^{2}\)) over time after each resting period or a decline in the flow curve that does not reach zero in the first part of the resting period indicates that the STRB is not working properly. The drained water curves from the Whitacre and Hanningfield pilot STRBs are similar to the drained water curves usually seen in full-scale STRBs for domestic wastewater sludge: there is a first peak that within a few hours declines towards zero flow (Figure 13). The highest infiltration rate was between 0.015 and 0.03 L/s/m\({}^{2}\). The dewatering process at the Hanningfield pilot and full-scale STRB was good without surface clogging or water ponding. The drained water quality showed that there was no bypass of sludge in the pilot beds [53; 58; 60].  
Generally, the results from pilot and full-scale STRBs receiving WW sludge show that this sludge type can be effectively treated in an STRB if they are properly constructed and operated.  
Figure 11: Residual sludge layer thickness (cm) in Beds 1–3 at the pilot STRB at the Whitacre WW during July–December 2015 [53].  
Figure 12: Pictures of the residual sludge surface at the Whitacre pilot STRB at the end (**left**) and at the start of the resting period (**right**) (courtesy of Orbicon).
# Investigations on Millimeter-Wave Indoor Channel Simulations for 5G Networks
## 3 Methodology and Simulation Setup
WI calculates the RMS-DS directly so the user can have this information from the extracted data. Figure 2: Strongest propagation paths for the LOS experiment at 60 GHz.
## 2 Literature Review
Moreover, upon completion of a project, a verification may be conducted to ensure that the model remains capable of accurately estimating the project's final cost. Aiming to offer cost estimation methods for new building development, the studies mentioned previously all made this endeavor. A research project examining the cost performance of renovation projects, also referred to as building reconstruction, was located. [PERSON] et al. [45] attempted to examine this difficult setting and suggested an ANN-based model to compute a cost performance score using information known at the start of the building process. They conducted a survey among industry experts. The goal was to understand overspending and subpar work in 50 reconstruction programs. They recorded every real expense variation from the estimated numbers. They also noted the project control techniques used. Two measures of financial deviation were employed: client fee delays and building constructor repair expenses. Out of 36 independent variables, 18 were selected. These were believed to impact cost-effectiveness. The variables were related to project management methods and tools. These included timeline, quality, cost, safety, and interaction methods and tools. They also included scope definition, bidding, and project completion methods. To construct their models, they used statistical analysis (Systat) and an ANN (Neuro Shell2). The ANN's model proved more sensitive to a greater variety of factors, even if the two techniques' performance was equivalent. Utilizing the schedule and cost predictions given at the beginning of construction, this study served as the inspiration for research work to design an ANN model for actual cost prediction and mostly ex-post verification of building renovation projects in the field to predict and mostly verify final cost variances. In the field of building renovation project cost estimation, an effort was made by the authors [44] that utilizes IBM SPSS Statistics tools to create, train, and test an ANN model. It relies on extensive review of the literature and actual renovation data from construction businesses. The model employs starting cost, projected duration, and initial demolition cost as a radial basis function technique to provide the foundation for inputs. The model demonstrates excellent accuracy with near 0% relative error and up to 2% sum of squares error, proving the practicality of the ANN in estimating the overall cost of renovations. It was the initial ANN model for building renovation project final cost prediction that has been published, as far as the authors are aware. Table 1 provides an overview of the methods, sources of data, and other components that the aforementioned researchers and more employed. \begin{table}
# Fabrication of Stretchable Transparent Electrode by Utilizing Self-Induced Vacuum Force
## 2 Fabrication Methods
### Fabrication Procedure  
A stretchable electrode was fabricated by transferring the electrically conductive line from the silicon wafer to the elastomer. Figure 3 depicts the fabrication procedure in detail. First, the prepared composite slurry was poured onto the silicon wafer, on which the electrode lines were etched in advance (step 1). Doctor blades were used on the silicon wafer to fill the slurry into the intaglio line pattern, as well as remove the excess slurry from the surface of the silicon wafer (step 2). After this, the silicon wafer was immediately coated with the thermoset elastomer PDMS, while the slurry was still wet (step 3). The elastomer was then cured in a convection oven at 100 \({}^{\circ}\)C for 10 min (step 4). Following the curing, the elastomer was peeled off, and the electrode lines were transferred from the silicon wafer to the elastomer (step 5). Finally, the fabrication procedure of the stretchable electrode was completed. There is a broad distinction between the proposed method and the conventional  
Figure 2: Preparation of intaglio-patterned mold on a silicon wafer. The procedure is based on the typical photolithography method [14].  
electrode-fabrication method. In the conventional method, the elastomer is applied onto the solid electrode pattern, following which the elastomer is cured using UV exposition or thermosetting. Meanwhile, in the proposed method, the thermoset elastomer is coated on the wet electrode pattern, then, the elastomer and the electrode are heated concurrently. In this way, a vacuum force is developed in the intaglio pattern; therefore, full penetration of the elastomer into the pattern is achieved.  
Figure 4 depicts the phenomena during the heating process. Initially, the pore area is filled with volatile solvent. During the heating process, the evaporation of the solvent is accelerated, thereby, inducing vacuum in the pores. Because of this self-induced vacuum in the pores, both the full penetration of the highly viscous elastomer into the pattern and the excellent transfer ratio of the electrode pattern, from the patterned silicon substrate to the elastomer, are achieved.  
Figure 4: Fabrication step 4. The self-induced vacuum force is driven by the available pores resulting from the evaporation of the solvent. Subsequently, the pore space is filled with the elastomer until the substrate is fully cured.  
Figure 3: Fabrication procedure of a stretchable electrode. Intaglio pattern is filled with electrically conductive material and then transferred to an elastomer substrate because of the high adhesive force between the electrode conductor and the elastomer substrate, in the peeling-off step. The self-induced vacuum force resulting in the penetration of the elastomer into the pattern is driven during the curing process (step 4).
## 3 Results and Discussion
### Experimental Design and Analysis of Variance
#### 3.2.3 Optimization of Experimental Procedures  
The response surface plots were shown in Figure 3, it was simple to evaluate the presence of any interactions between two variables and to determine the optimum values of the variables.  
Figure 3a,c,e showed extraction time (\(A\)), extraction temperature (\(B\)) and pH (\(D\)) had important influences on the yield of PSP, and the interactions between different functions (extraction time and extraction temperature; extraction temperature and pH) also produced very significant influences on the extraction yield. Whereas enzyme concentration (\(C\)) exerted a weaker effect on the yield (Figure 3b,d) and the interaction between enzyme concentration and pH was insignificant (Figure 3f).  
Based on Figure 3, it could be deduced that the optimal EAE conditions were as follows: Extraction temperature of 59.90 \({}^{\circ}\)C, extraction time of 42.78 min, enzyme concentration of 2.52%, and pH of 6.10. Under these conditions, the maximum response was 3.24% predicted by the model.  
Figure 2: Estimation of the model precision. (**A**) Plot of predicted and actual values; (**B**) The normal % probability plot; (**C**) Plot of internally studentized residuals versus actual run.
# Analysis and Investigation of Dual-Polarized Color LED Based Visible Light Communication System
###### Abstract
Due to the two mixed VLCs with various modulation formats, it would also generate signal mutual interference to cause a security procedure in the physics layer [23]. To decode the dual-polarized signals, two orthogonal POLs with precise direction are required at the Rx side. Moreover, if there are many clients with only one Rx detector in the same room for receiving the dual-polarized VLC signal, the polarization of POL at each client can be controlled properly to share the total capacity. As a result, compared with the previous work [17; 18; 19], the presented 2 \(\times\) 2 PDM G-B LED VLC system can not only achieve >1120 Mbit/s through 4 m wireless link at very low illuminance status but can also provide signal security in the physical layer when the same color LEDs are used.
# Analysis and Implementation of a Hybrid DC Converter with Wide Voltage Variation
###### Abstract  
A new hybrid DC converter is proposed and implemented to have wide voltage variation operation and bidirectional power flow capability for photovoltaic power applications. The hybrid DC converter, including a half- or full-bridge resonant circuit, is adopted to realize the bidirectional power operation and low switching losses. To overcome the wide voltage variation problem (60 V-480 V) from photovoltaic panels due to sunlight intensity, the full-bridge structure or half-bridge structure resonant circuit is used in the presented converter to implement high or low voltage gain under a low or high input voltage condition. Using a pulse frequency modulation (FPM) scheme, the voltage transfer function of the resonant circuit is controlled to regulate the load voltage. Due to the symmetric circuit structures used on the primary and the secondary sides in the proposed converter, the bidirectional power flow can be achieved with the same circuit characteristics. Therefore, the proposed converter can be applied to battery stacks to achieve charger and discharg operations. Finally, a 400 W prototype is implemented, and the performance of the proposed hybrid DC converter is confirmed by the experiments.  
hybrid DC converter; bidirectional power flow; wide voltage variation; soft switching +
Footnote †: : 2021: 11, 10211. [[https://doi.org/10.3390/appl12110211](https://doi.org/10.3390/appl12110211)]([https://doi.org/10.3390/appl12110211](https://doi.org/10.3390/appl12110211))
# PFC Inductor Design Considering Suppression of the Negative Effects of Fringing Flux
## 1 Introduction
An air gap enables optimization of the dimensions of the core and also meets the stabilization function of the component. Care must be taken not to exceed the value of \(B_{m}\) due to the consequent drop of the relative permeability and value of inductance. Although induction \(B\) is the same in the air gap as in the ferromagnetic part, it has a large magnetic resistance due to the low permeability of the air gap. As a result, most of the intensity of the magnetic field is concentrated in the air gap. The product of \(B\) and \(H\) is related to energy density, and it follows that most of the energy is stored in the air gap. It further follows that the resulting magnetic core may be smaller. The ferromagnetic part of the magnetic circuit then acts as a pole piece, which allows realizing an air gap of defined, relatively small length, and dimensions reflecting the arrangement of the winding. In summary, it is valid that achieving the required value of inductance a coil without an air gap would have significantly larger dimensions than a coil of ferromagnetic material with an air gap. The length of the air gap must be selected correctly because of the side effect of the fringing flux (Figure 1), which is responsible for the increase in component losses. If the air gap is too long, the magnetic flux of the core would interfere with the winding. In contrast, a small air gap requires a larger core and thus the volume of the resulting converter would be increased. Figure 1: Representation of the magnetic core without air gap (**left**), with small air gap (**middle**), and with large air gap (**right**).
# Key-Recycling Strategies in Quantum-Key-Distribution Networks
###### Abstract  
Quantum-key-distribution (QKD) networks can provide absolutely secure keys for the entire communication system in theory. At present, the key-distribution rate is relatively low, and the key-distribution rate decreases exponentially as the distribution distance increases. The trusted-relay scheme commonly used in existing QKD networks achieves the purpose of extending the security distance by consuming additional keys. Since the channel is unreliable, the key-relay process will accumulate system errors to a certain extent, increasing the probability of key-relay failure. In some high-bit-error-rate network scenarios such as wireless networks and disaster environments, the channel-error rate is as high as 30-50%. And in these scenarios, there are usually a large number of confidential messages that need to be delivered. However, the key-management mechanism of the current QKD system does not consider the scenario of key-relay failure. If the key is not successfully relayed, all the keys participating in the relay process will be destroyed, including the key that has been successfully relayed before. This situation causes the key to be wasted and reduces the encryption capability of the system. In this paper, we proposed the quantum-key-recycling (QKR) mechanism to increase the number of keys available in the network and introduced a secure service grading mechanism to properly reuse the recycled keys. The QKR mechanism can be regarded as a key-management mechanism acting on the point-to-point QKD system, and the mechanism is designed for a classical channel to reuse the key resources. A post-processing method for recycled keys is proposed to improve the security of the keys. Simulation results show that the QKD network using the key-recycling strategy is about 20% higher in key-utilization rate than the traditional QKD network without the QKR mechanism, and about 10% higher in-service security coverage.  
Quantum key distribution (QKD); quantum key recycling; service security level +
Footnote †: journal: Applied Physics Letters
## 3 Resonators: Materials and Geometries  
Resonators are highly appealing components for improving the performance of patch antennas due to their ability to modify the overall antenna performance. Indeed, the combination of material and geometry for building a resonator can significantly influence the radiation pattern and scattering parameter \(S_{11}\) of patch antennas. By examining various materials with distinct electromagnetic properties and geometries, it is possible to develop customized solutions that meet the specific requirements of different applications. To conduct a comprehensive investigation, it is essential to carefully select appropriate combinations of materials and geometries. Accordingly, Section 3.1 details the dielectric and conductive materials considered in this study, while Section 3.2 discusses the geometries used to shape these materials and, ultimately, construct resonators.
## 4 Simulation Model Design
### Simulation Logic  
The simulation logic was built by applying the conceptual management model for air mobility described in Figure 5, with a special focus on the modules seven, eight, and nine, referring to the capacity-constrained operations and maintenance modules and the related service indicators including delays and backlogs. For this purpose, only the simulation-related conceptual model was considered, as shown in Figure 13.  
First, the demand module was built outside of the simulation model with different mobility demand patterns with origin and destination mobility needs for any given simulation period. Next, the air mobility network as well as the services and means were defined based on the characteristics described in Section 4.3. Finally, the model would also calculate or derive other indicators such as emission reductions, cost savings, time savings, etc. for external monitoring or reporting.  
Figure 12: Model Network Design and related parameters.  
Figure 13: Simulation logic.  
The input data for the simulation model was prepared by defining the following parameters in Microsoft Excel files:  
* Demand of mobility between stations with origin and destination. For each time period, flight requests for each origin-destination combination were generated. Therefore, customized air mobility scenarios could be generated to simulate the on-demand nature. The data were read by the system dynamics simulation model.
* Average transportation lead time between all combinations of vertiports, standard deviation of the transportation lead time between vertiports, as well as the maximum and minimum values for the lead times between locations were also defined and read from the simulation model. Therefore, the model allowed changes to the lead time parameters from its origin-destination combination  
The simulation model was built in Vensim. For this purpose, stock with capacity limitations was built for the fifteen vertiports as well as transportation streams of aircraft units between vertiports and their transportation times.