esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Results and Discussion
### Study on Flow Control of Vertical Tail under Different Sideslip Angles  
The flow control at a negative sideslip angle under typical working conditions is studied, and the increment and mechanism of flow control on the vertical tail lateral force coefficient under different sideslip angles from \(0^{\circ}\) to \(-10^{\circ}\) are studied. Figure 15 shows the curve diagram of the lateral force increment of the vertical tail model under different sideslip angles after the flow control is applied. When the sideslip angle is negative, the lateral force increment brought by the actuator is significantly lower than that under zero sideslip, but the lateral force increment can basically reach 30%, which can significantly improve the yaw control capability of the aircraft at negative sideslip angles. When the sideslip angle is \(-10^{\circ}\) and the rudder deflection angle is 40\({}^{\circ}\), the maximum lateral force increment caused by the oscillating jet can reach 35.6%.  
A negative sideslip angle is a typical condition for civil aircraft to take off and land in a crosswind, so the space flow field of the vertical tail at a \(-10^{\circ}\) sideslip angle is measured and studied. Figure 16 shows the spatial flow field distribution of the vertical tail model, \(\beta=-10^{\circ}\) and \(Re=\) 2.12 \(\times\) 10\({}^{5}\). The mainstream dimensionless velocity on the stability surface accelerates from 0.86 to 0.93. When the rudder deflection angle is 15\({}^{\circ}\), partial flow separation occurs at the trailing edge of the rudder without control, but no vortex structure is observed, similar to the case when the sideslip angle is 0\({}^{\circ}\). When the excitation is applied, the flow separation is suppressed, and the separation area on the rudder is reduced. The increase in the actuators' velocity and the velocity of the rudder upper wing surface can improve the flow field characteristics of the vertical tail under the condition of a negative sideslip angle. When the rudder deflection angle is increased to 30\({}^{\circ}\), the airflow on the upper wing surface of the rudder is completely separated. The velocity is close to 0, and a wholly separated vortex can be observed. The inhibition of flow separation after flow control is applied. Applying flow control does not eliminate the separation vortex in the rudder well, but it makes the separation vortex move upstream. The low-speed region downstream of the rudder is accelerated significantly, and the dimensionless velocity increases from 0.08 to 0.69. Compared with the zero sideslip angle, the flow acceleration area at the exit of the actuator and on the wing surface of the stabilizer is smaller at this sideslip angle, which is one of the factors that cause the vertical tail lateral force increment to be lower than the zero sideslip angle.  
The PIV results explain the vertical tail lateral force variation and are consistent with the ground pressure data. They powerfully reveal the flow control mechanism of the jet.
# Floating Step-Down Converter with a Novel Lossless Snubber
## 2 Main Power Stage
### Circuit Structure and Its Definitions  
Figure 1 shows a step-down converter with the proposed lossless snubber, whose circuit consists of a main power switch \(Q_{1}\), three diodes \(D_{1}\), \(D_{2}\), and \(D_{3}\), an output capacitor \(C_{o}\), a resonant capacitor \(C_{r}\), an output inductor \(L_{o}\), and a resonant inductor \(L_{r}\), while the load side consists of an LED string called \(LS1\).  
Prior to analyzing the circuit operation, a brief explanation of the definition of the associated symbols and the required assumptions is presented:  
1. \(V_{in}\) is the input DC voltage, and the output capacitor \(C_{o}\) is large enough, so it is viewed as a voltage source, named \(V_{o}\).
2. The main power switch \(Q_{1}\), the main diode \(D_{1}\), the output inductor \(L_{o}\), and the output capacitor \(C_{o}\).
3. The load is constructed by some LEDs connected in series, named \(LS_{1}\).
4. For the main power switch \(Q_{1}\), its parasitic output capacitance \(C_{oss}\) is taken into account, and the on-time of \(Q_{1}\) is expressed as \(DT_{s}\), where \(D\) is the duty cycle and \(T_{s}\) is the switching period.
5. The lossless snubber is built up by the resonant inductor \(L_{r}\), the resonant capacitor \(C_{r}\), and the diodes \(D_{2}\) and \(D_{3}\).
6. \(i_{ds}\) is the current in \(Q_{1}\), \(i_{Lr}\) is the current in \(L_{r}\), \(i_{Lo}\) is the current in \(L_{o}\), and \(i_{D1}\) and \(i_{D3}\) are the currents in \(D_{1}\) and \(D_{3}\), respectively.
7. \(v_{ds}\) is the voltage on \(Q_{1}\), and \(v_{Cr}\) is the voltage on \(C_{r}\).
8. \(I_{Lrk}\) and \(V_{Crk}\) are the initial values of \(L_{r}\) and \(C_{r}\), respectively, where the value of \(k\) can be 0, 1, 2, 3, or 4.
9. All components are regarded as ideal except the main power switch.  
Figure 1: Floating step-down converter with lossless snubber.  
10. The circuit is operated in the continuous conduction code (CCM). Figure 2 shows the illustrated waveforms of the circuit over one switching period, and there are five operating states to be described as follows.
## 6 Conclusions  
A detailed and complete landslide inventory is the basis for landslide susceptibility assessment, and landslide susceptibility mapping is of great significance for disaster prevention and mitigation of earthquake-triggered landslide hazard. This work attempted to establish a detailed landslide inventory of the 2018 Tomakomai, Japan Mw6.6 earthquake and used the LR and SVM to carry out the susceptibility mapping for the affected area. Based on the planet images acquired within a few days after the earthquake, a comprehensive and objective earthquake landslide database was obtained within 1 month, so that the results can be applied to the medium-term resettlement and reconstruction.  
To compare the result quantitatively, the modeling results of landslide susceptibility were evaluated by comparing the maps with known landslide locations. For LR, more than 68.44% of landslides concentrate in areas of very low and very high susceptibility classes. For SVM, more than 89.6% of landslides concentrate in areas of high and very high susceptibility classes. The AUCs show that the SVM works slightly better than the LR method, the success rates of the LR and SVM are 84.7% and 90.9%, respectively. The prediction rates of the LR and SVM are 83.9% and 87.1%, respectively. Overall, the LND and LAD of the two models increase rapidly with the increase of the susceptibility level. This study explores the applicability of the logistic regression (LR) model and support vector-based model (SVM) in the study area, and the results provide a useful reference for earthquake disaster prevention and mitigation in the quake-affected area. Otherwise, the results can provide a scientific reference for the quick establishment of co-seismic landslide inventories and landslide susceptibility mapping based on landslide databases.  
The following are available online at [[http://www.mdpi.com/2072-4292/11/8/978/s1](http://www.mdpi.com/2072-4292/11/8/978/s1)]([http://www.mdpi.com/2072-4292/11/8/978/s1](http://www.mdpi.com/2072-4292/11/8/978/s1)), Table S1: Lithology description in the whole study area.  
**Author Contributions**: [PERSON] proposed the research concept, organized landslides interpretation work, and offered basic data. [PERSON] designed the framework of this research and wrote the manuscript. [PERSON] participated in writing article and data analysis. Other authors participated in landslides Interpretation.  
**Funding**: This work was supported by the National Key Research and Development Program of China (2017 YFB0504104).  
**Acknowledgments**: Thanks for PLANET company for providing us with pre- and post-earthquake images. We also express our gratitude to the anonymous reviewers for their comments and suggestions that improved the quality of our paper.  
**Conflicts of Interest**: The authors declare that there are no conflicts of interest.
## 5 Conclusions  
This paper derives direct position determination of non-circular sources for multiple arrays via weighted Euler ESPRIT data fusion. The proposed NC-Euler-WESPRIT algorithm takes full advantage of elliptic covariance information of NC signals to expand the virtual array aperture. By comparison with original two-step positioning technology and SDF technology, NC-Euler-WESPRIT algorithm has more available DOF. Secondly, this paper introduces the idea of Euler-ESPRIT and constructs a spectral function without complex multiplication. According to the running time of the algorithms, the proposed algorithm greatly reduces the complexity compared with the original SDF algorithm and NC-ESPRIT algorithm. In addition, the proposed algorithm reduces the performance loss caused by signal propagation loss in space as much as possible by weighting the received data of each observation station. Simulation results verify that the proposed NC-Euler-WESPRIT algorithm can effectively estimate the targets even when the number of array elements of each observation station is less than that of targets and its positioning performance is superior to original two-step positioning method and SDF algorithm. While our proposed method only considers the situation of uniform linear array, sparse arrays are now the focus of attention, which is the future work due to the fact that sparse arrays will bring great challenge on the non-circular signals.  
Figure 12: RMSE performance varying with snapshot (\(SNR=15\,\mathrm{dB}\), \(\sigma^{2}_{error}=70\)).  
**Author Contributions:** Conceptualization, X.S. and X.Z.; methodology, X.S.; software, X.S.; validation, X.S., X.Z. and H.Z.; formal analysis, X.S.; investigation, X.S.; resources, X.S.; data curation, X.S.; writing--original draft preparation, X.S.; writing--review and editing, X.S.; visualization, X.S.; supervision, X.S.; project administration, X.S.; funding acquisition, X.Z. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was supported by China NSF Grants (61971217) and National Key Research and Development Project Grant (2020 YFB1807602).  
**Institutional Review Board Statement:** Not applicable  
**Informed Consent Statement:** Not applicable  
**Data Availability Statement:** The data used to support the findings of this study are included within the article.  
**Conflicts of Interest:** The authors declare no conflict of interest.
## 2 Materials and Methods
### Human-Assisted Feature Extraction Methods
#### 2.2.1 Filtering and RR-Interval  
The first pre-processing step removes baseline wandering and offsets from the ECG signals. For this, two moving median filters of 200 and 600 ms window sizes are applied to the ECG signal to isolate the baseline signal, which is afterward subtracted from the ECG signal. Following R-Peak detection, the ECG signals segmented were extracted with a window length of 90 samples before and 90 samples, presented in Figure 3. The R-peak locations and RR-intervals were extracted using the BioSPPy (v.0.7.2)1 Python module [32]. Eight RR-interval features were also extracted based on [PERSON] et al. [11]: (1) Pre-RR: the distance between the actual R-peak and the previous one, (2) Post-RR: distance between the actual R-peak and the next one, (3) Local-RR: average of the ten previous Pre-RR intervals, (4) Global-RR: average of the Pre-RR values produced in the signal and the normalized values from each of the four intervals.  
Figure 3: (**Top**) R-peak-centered ECG segments with a +90 and \(-\)90 sample window. (**Bottom**) Wavelet transform applied on the example segments 1–7 and (**bottom**) the Daubechies (db1, level 3) wavelet function.
# A Novel Strategy for VNF Placement in Edge Computing Environments
## 4 Challenges of VNF Placement in Edge Environments
### Heterogeneity and Dynamism of Resources in Edge Environments  
Edge nodes must provide the computational resources required by VNFs to host them successfully. In other words, edge nodes must offer sufficient CPU and memory capacity to provide the minimum resources required by VNFs. Additionally, edge nodes need to be able to provide the VNF type that is being requested. At the edge tier, there are edge nodes with different computational resource capacities that can provide different types of VNFs. Therefore, the edge environment has highly heterogeneous available resources (CPU and memory) among nodes.  
Furthermore, VNFs must deal with various link bandwidth capacities among those nodes. Link bandwidth is an essential resource to be provided to SFCs since they comprise a set of chained VNFs, which must be processed in a predefined order for the success of the SFC processing. Thus, not only the computational resources of edge nodes must be capable of meeting VNF requirements, but also link bandwidth among them must be able to forward the traffic to the chained VNFs.  
Moreover, edge nodes vary their computational capacity as they host new instances and free up resources when some instances are removed. Consequently, the link bandwidth varies as well. Such dynamism of computational resources and link bandwidth, added to the heterogeneity of nodes and links, makes the VNF placement a complex task.
# Design and Optimization of Lattice Structures: A Review
## 4 Design and Optimization of Non-Uniform Lattices
### Non-Uniform Lattice Structures Based on Functional Gradient Design  
Gradient structures are very common in nature, which have variable density and porosity, and can combine a variety of unit cells with different topological structures. Compared with uniform lattice structures, gradient structures show different mechanical properties. Various gradient properties can be obtained to achieve different levels of functionalities and characteristics, by varying the design parameters such as cell size, strut length, and strut diameter of the unit cells in lattice structures [73]. Additionally, Voronoi-tessellation is also one of the important methods to form gradient lattice structures. Because Voronoi-tessellation is a method of space division, many points are distributed in a specific Euclidean space. Using Voronoi-tessellation to design non-uniform lattice structure can realize lightweight anisotropic lattice structure with gradient.  
[PERSON] [186] and team proposed a top-down design method based on Voronoi-tessellation, which successfully obtained a special, multi-functional, gradient non-uniform lattice structure. Through the quasi-static compression test, they showed that porosity and irregularity had huge influence on the mechanical properties of materials. Figure 18 showed the gradient lattice structure formed by the top-down Voronoi-tessellation method.  
Figure 17: Topology optimization of uniform lattice structure [183]: (**a**) unit cell; (**b**) lattice structure.  
[PERSON] et al. [190] investigated the mechanical response of gradient lattice structures manufactured via SLM. They designed and manufactured gradient discrete lattice structure, gradient increasing lattice structure, and gradient decreasing lattice structure respectively (as shown in Figure 19). By comparing with regular lattice structure, they pointed out that the special mechanical behaviors of lattice structures with gradient topologies made them attractive for energy absorption applications.
###### Abstract  
Portalable wireless communication systems are increasingly in demand in small sizes for human convenience. In wireless communication systems, the performance, size, and unit cost are very important. A band\(-\)pass filter is important to sharp cut-off frequency characteristics, size, and frequency selectivity in wireless communication systems. The band\(-\)pass filter has three types of techniques in the transmission\(-\)zero method, stub\(-\)loaded resonator, and stepped impedance resonator for the sharp cut\(-\)off frequency characteristic, adjustable bandwidth, and excellent frequency response characteristics. To obtain these characteristics, the impedance ratio and length of a stub are mainly adjusted. It also utilizes a multi-mode technique to increase bandwidth. However, it is analyzed that the problem of reducing the size of the device still remains. To solve these problems, the paper is applied to a stub\(-\)loaded resonator and a stepped impedance resonator to control the impedance ratio and the length of the stub to obtain the results of the transmission\(-\)zero method, bandwidth control, and size reduction through the folded structure. Dual\(-\)band bandwidth was secured by integrating a T\(-\)shaped band\(-\)stop filter. The designed band\(-\)pass filter has center frequencies of 243 GHz and 7.49 GHz, and the insertion loss of a proposed band\(-\)pass filter is 0.102 dB and 0.103 dB. Additionally, the return loss of a proposed band\(-\)pass filter is 19.13 dB and 19.96 dB, respectively. The bandwidth of a filter is 120% and 105%, respectively. The size of the filter is 0.0708 \(\lambda\)g \(\times\) 0.0533 \(\lambda\)g. The designed filter has a good skirt phenomenon, small size, low insertion loss, and dual\(-\)band characteristics.  
reduced; 12 August 2021  
13 August 2021  
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# Experimental Study on the Effect of Wind Speed on Hail Impacts
###### Abstract  
Hailstorms, exacerbated by global warming, inflict escalating economic losses on infrastructure, yet existing research overlooks wind-hail synergy in impact dynamics. This study employs a wind-tunnel-integrated hail impact simulator to analyze how wind speed, hail diameter, and velocity collectively influence impact behavior. Key results reveal that higher wind speeds shorten the impact duration, accelerate peak force attainment, and amplify peak forces by up to 18.9% compared to windless conditions. Smaller hailstones exhibit reduced wind sensitivity, while combined increases in wind speed and hail diameter/velocity proportionally elevate peak forces. Momentum transfer from wind-driven fragmented hail clusters enhances force generation, demonstrating wind's critical role in damage potential. A multivariate regression model predicting peak impact loads is proposed, offering actionable insights for wind-hail-resistant structural design.  
hailstone; impact; wind-hail coupling; wind tunnel test; multiple linear regression analysis +
Footnote †: journal: Applied Sciences
# Black Ice Classification with Hyperspectral Imaging and Deep Learning
## 2 Related Works  
In Figure 1, yearly traffic accidents in Korea caused by black ice for 24 h are shown [19]. According to the graph, the majority of the accidents caused by black ice occur in the morning from 6 a.m. to 10 a.m. From the figure that is provided by an official source, we can observe 80-85% of the accidents caused by black ice occur during the daylight. In [20], multi-wavelength, non-contact optical technology was used as a method for detecting  
Figure 1: Traffic accidents in South Korea in a day due to black ice [19].  
black ice, pointing out the differences in normalized reflectance under dry, wet, black ice, snowy, and icy conditions. In [21], to develop a black ice detector, optical sensors and an infrared thermometer were used. An infrared camera has also been used to identify road conditions by using deep learning [22]. Using a millimeter wave sensor with a deep learning model (a 1D Convolutional Neural Network), another detection method achieved 98.2% accuracy [23]. However, mmwave technology is hard to manage in rain and fog when the black ice forms [24; 25], as it suffers from attenuation in this kind of situation. Compared to hyperspectral images, the data are also a bit complicated for preprocessing and other custom settings.  
In this paper, for the first time, we introduce a hyperspectral imaging system with deep learning to analyze black ice. One of the advantages of using hyperspectral imaging is that it needs no prior information on a sample, and it can take advantage of spatial relationships among the spectra in a neighborhood, which allows more accurate classification models. In the following section, we discuss more about the methodology and implementation details. Due to a lack of research on black ice detection with computer vision and hyperspectral imaging, we have compared our proposed method to Fast 3D CNN [18], which is one of the state-of-the-art methods for hyperspectral image classification.
## 5 Conclusions  
(1) In this paper, aiming at the interference problem in wireless sensor networks, a simple solving scheme of physical layer is proposed, which is based on EBPSK modulation.  
(2) EBPSK modulation as a new idea, which takes some current binary modulations as its special examples, has good flexibility, universality and good possibilities for new high speed and high efficiency transmission [10].  
(3) The special impacting filter can transform the tiny waveform difference into amplitude impacting, so that the receiver structure can be simplified by threshold detection [7,8]. The EBPSK transmission system can be digitally implemented which is benefit for chip integration and advances the EBPSK scheme to practicality.  
(4) This paper discusses the anti-interference performance of EBPSK system itself. When the initial phase of the co-channel interference is small, EBPSK system has good anti-interference characteristics, which has been analyzed by intuition and proved by simulation results. While with the increasing of the initial phase, the anti-interference performance of system itself decreases, so the usual anti-interference methods can be considered to solve it. Therefore, the anti-interference performance may extend the use of EBPSK system in interference environments. Researches on this problem are underway, so for the case of the large interference initial phase, the detailed anti-interference scheme based on the EBPSK system would be given in the forthcoming papers.