esa-sceva/satcom-chunk-collection huggingface dataset:
# Performance Optimization Design of Diagonal Flow Fan Based on Ensemble of Surrogates Model
## 2 Research Object and Method
### Computational Model and Mesh Blocking  
We simplified the physical model and selected the fan flow components. At the same time, in order to improve the accuracy of fan performance prediction, the inlet and outlet areas were extended, and the extension length was 5 times the outlet diameter.  
Figure 1: Physical model of small diagonal flow fan.  
According to the actual position of the rotating parts and the static parts of the fan, the whole diagonal flow fan basin was divided into five parts, which are the inlet basin, moving blade basin, guide vane basin, diffuser basin, and outlet basin. Figure 2 is the simplified fan basin diagram.  
Grid blocking of five different basins was carried out. Because the simulation results are greatly affected by the grid, in order to improve the calculation accuracy, TurboGrid was used to generate the structural grid for the rotor blade basin and the guide vane basin of the core components of the fan, and the rest of the flow components were unstructured. Figure 3a shows the grid of the impeller region, and Figure 3b shows the grid diagram of the guide vane area. When meshing, the first node must be located in the viscous bottom layer. The dimensionless distance between the first grid and the wall is generally expressed by y+, and it is generally believed that the y+ value here is less than 5 [12]. The empirical formula of y+ is:  
\[Y_{wall}=6\Big{(}\frac{V_{ref}}{v}\Big{)}^{-\frac{7}{8}}\Big{(}\frac{L_{ref}}{ 2}\Big{)}^{\frac{1}{8}}y^{+} \tag{1}\]  
where \(V_{ref}\) is the reference speed, m/s; \(L_{ref}\) is the reference length, m; \(v\) is the kinematic viscosity of fluid, m\({}^{2}\)/s; and \(y^{+}\) is a dimensionless parameter. The grid height of the first layer of the boundary layer should be less than 0.6 mm calculated by an empirical formula.  
After the grid quality meets the requirements, it is also necessary to verify the independence of the number of computational grids. Too few grids can easily make the calculation results unstable, but when the number of grids reaches a certain threshold, the calculation accuracy is difficult to improve. As shown in Figure 4, when the total number of fan nodes reaches approximately 2.5 \(\times\) 10\({}^{6}\), the calculation results of the fan flow and total pressure remain basically stable. Therefore, considering the relationship between the prediction accuracy and computation time, the selected computational num  
Figure 3: Grid model of diagonal flow fan. (**a**) Moving blade area grid. (**b**) Guide vane area grid.  
Figure 2: Fan basin diagram.
# A Simple Estimation Method of Weibull Modulus and Verification with Strength Data
###### Abstract  
This study examines methods for simplifying estimation of the Weibull modulus. This parameter is an important instrument in understanding the statistical behavior of the strength of materials, especially those of brittle solids. It is shown that a modification of [PERSON]'s approximate expression can provide good estimates of Weibull modulus values (m) in terms of average strength (<\(\alpha\)>) and standard deviation (S): m = 1.10 <\(\alpha\)>/S. This modified [PERSON] relation is verified on the basis of 267 Weibull analyses accompanied by <\(\alpha\)> and S measurements. Estimated m values matched normally obtained m values on average within 1%, and each pair of m values was within \(\pm\) 20%, except for 11 cases. Applications are discussed, indicating that the above relation can offer a quantitative tool based on the [PERSON] theory to engineering practice. This survey suggests a rule of thumb: ductile metal alloys have Weibull moduli of 10 to 200.  
Weibull modulus; estimation methods; modified [PERSON] relation; strength data; observed datasets; large-scale data +
Footnote †: journal: Applied Sciences
# Fast and Robust Object Tracking Using Tracking Failure Detection in Kernelized Correlation Filter
## 4 Experimental Results
### Tracking Performance of the Proposed Method Based Tracker and Original KCF Based Tracker  
We found meaningful improvements in the sense of tracking accuracy from evaluations performed using the proposed tracker and the original KCF tracker. As shown in Figure 11a, in evaluation using various datasets, the original KCF tracker failed in tracking while the proposed tracker performed successful tracking and yielded improved tracking accuracy. At least one challenging scene is included in these sequences, the proposed tracker outperformed original KCF tracker because of the re-tracking process. The proposed tracker and the original KCF tracker yielded comparable results in some other datasets in which both trackers have successfully tracked the targets as shown in Figure 11b. Lastly, both of trackers have failed in tracking in datasets named DragonBaby and Jumping where the targets are moving rapidly as shown in Figure 11c.
# Impacts of Thermal Maturity on the Carbon Isotopes of
## 1 Introduction
The experimental result has shown that the Total Ion Chromatography (TIC) of hopanes was consistent with the distribution characteristics of the \(m/z\) 191 mass chromatogram, and the isolated hopanes could meet the detection requirements of isotope ratio mass spectrometry. This method effectively facilitates the separation, enrichment, and purification of the complete series of hydrocarbon compounds from crude oil or rock extracts. As the development of testing technologies for the carbon isotopes of monomeric propane hydrocarbons and thermal simulation experiments, the evolution of the chemical and isotopic compositions of propane compounds during thermal maturity can be more effectively studied. In this study, a low maturity lacustrine shale sample from Paleogene Kongdian Formation in Bohai Bay Basin was pyrolyzed in semi-open systems that are more similar to geological conditions [31]. The vitrinite reflectance (\(R_{\rm o}\)) of the artificially matured samples range from 0.72% to 1.28%. The hopane compounds were separated from saturated hydrocarbons, and their carbon isotopes were determined. The study aims to explore the change of carbon isotope of monomer hopane in lacustrine shale during thermal maturation. This will provide reliable evidence for comparing the carbon isotopes of hopane compounds in samples of differing thermal maturity levels and promote the application of carbon isotopes of hopanes.
# A Circularly Polarized Antenna Array with Gain Enhancement for Long-Range UHF RFID Systems
## The Proposed Antenna Design
### SICL-Based Feed Network  
SICL technology [15] was chosen for the implementation of the antenna array feed network. This is a non-disperse structure which can propagate the transverse electromagnetic (TEM) mode.  
Figure 3: Simulated performance comparison of the antenna array with one and two levels of SR: (a) S\({}_{11}\), (b) axial ratio (AR) and, (c) left-handed circular polarization (LHCP) broadside gain.  
Figure 2: Representation of antenna array feed networks: (a) one level and (b) two levels of sequential rotation (SR).  
The lateral shielding due to the metallic holes (Figure 4) avoids parallel-plate mode propagation, reducing leakage and interference with other lines. Moreover, SICL can be implemented using the conventional multilayer printed circuit board (PCB). For the sake of an easier connection between the metallic patch and the feed network transmission line, a coplanar waveguide (CPW) transition [22] was introduced at each output port of the feed network. Feed network dimensions were synthesized according to [15] and optimized with ANSYS HFSS.  
The simulated performance was compared with that of a microstrip technology-based feed network (similar to the one described in [23]), and the results are shown in Figure 5. Wider S\({}_{11}\) and AR bandwidths were found for the SICL-based array, with a gain enhancement of about 1 dB with respect to the microstrip-based feed network, and a wider 3 dB gain bandwidth.  
Figure 4: Substrate-integrated coaxial line (SICL) structure. (**a**) Transmission line: top and lateral views; (**b**) SICL to coplanar waveguide (CPW) transition: top and lateral views.  
Figure 5: Simulated performance comparison of the antenna array with microstrip-based and SICL-based feed networks: (**a**) S\({}_{11}\), (**b**) AR, and (**c**) LHCP broadside gain.
# A New Multi-Objective Unit Commitment Model
## 2 Model
### Multi-Objectives Model  
Most of the multi-objective methods tend to seek the optimal Pareto front, then select a single solution among the non-dominated solutions based on some criterion. Although finding the Pareto front could work in parallel, a complete front is required to find the compromise point. See Figure 1. We optimize over the criterion directly, which could find the solution more satisfied with the criterion and avoid looking for the Pareto front.  
The \"criterion\" here is to minimize the Euclidean distance between non-dominated solution and the Utopian point. The Utopian point is the infeasible solution with each entry corresponds to the objective of a single-objective optimization problem [33]. For example, the objective of single-objective optimization \(min\)\(f1\) is the \(f1_{min}\), while the objective of \(min\)\(f2\) is the \(f2_{min}\). The Utopian point could be (\(f1_{min}\)/\(f2_{min}\)).  
To optimize the criterion, the objective could be formed using the following formula.  
\[\min F=\sqrt{{F_{1}^{\prime}}^{2}+{F_{2}^{\prime}}^{2}} \tag{11}\]  
where \(F_{1}^{\prime}\), \(F_{2}^{\prime}\) are the normalized objective of \(F_{1}\) and \(F_{2}\). Please note that minimize \(F\) is equivalent to minimize \({F_{1}^{\prime}}^{2}+{F_{2}^{\prime}}^{2}\), which is easier to be optimized. We regard \(F\) as MOUC cost.
# Feature Integration Strategies for Neural Speaker Diarization in Conversational Telephone Speech
## 4 Results and Analysis
### Multi-Speaker Scenario  
This section presents our key findings and analysis for multi-speaker diarization scenarios. For detailed experimental results, including full performance metrics across all feature configurations and evaluation criteria, we refer readers to Tables A1-A9 in Appendix A, which provide a complete breakdown by feature type (MFB, ECAPA-TDNN \(\oplus\) MFB, and GeMAPS \(\oplus\) MFB, respectively).
## 2 Related Work
This system uses RSSI and channel state information (CSI). To solve the challenge of RSSI signals, [24] suggested a Wi-Fi RSSI signal-based positioning system that employs RSSI heat maps rather than RSSI raw values. However, these deep learning model-based positioning systems use raw RSSI data from APs to perform positioning. According to experimental findings, among all current deep learning techniques, the proposed Wi-Fi RSSI heat map-based positioning system using HDLM offers the best positioning accuracy. The primary objective of this paper is to improve the precision of positioning in confined areas, specifically outperforming the transferrable sensor capabilities provided by IEEE 802.15.4 standard sensors in open spaces. Additionally, we investigate efficient methods for interpretating fluctuations in radio wave intensity emitted from stationary nodes, which exhibit a logarithmic decrease and are not directly correlated with distance. We use a multi-layer perceptron (MLP)-based technique using the B-spline curved equation to determine the final coordinates and achieve more refined position tracking. The remainder of this paper is organized as follows. Section 3 provides a detailed explanation of an indoor location system that utilizes the MLT mechanism based on the RSSI measurements. In Section 4, the proposed strategy is elaborated upon. The experimental design and findings, as well as any relevant discussion, are presented in Sections 5 and 6, respectively. Finally, Section 7 offers an overview of the study's findings.
# A Novel Piezoelectric Ceramic Actuator with Scissoring Composite Vibration for Medical Applications
## 4 Experimental Analysis and Discussion
### Experimental Setup  
A laser vibrometer (Polytec PSV-300) was employed to rapidly measure the real vibration mode of the actuator (Figure 9). Owing to the small beam thickness (0.5 mm), the scanning network could  
\begin{table}
\begin{tabular}{l c c} \hline \hline
**Parameter** & **Piezoelectric Stack** & **Unit** \\ \hline Displacement & \(9.1\pm 1.5\) & \(\mu\)m \\ Generated force & 200 & N \\ Resonance frequency & 138 & kHz \\ Capacitance & 0.18 & \(\mu\)F \\ Insulation resistance & 100 & M\(\Omega\) \\ Maximum driving voltage & 150 & VDC \\ \hline \hline \end{tabular}
\end{table}
Table 2: The performance parameters of the piezoelectric stack.  
Figure 8: The prototype of the proposed scissoring actuator with a beam tip of 7 mm.  
not be drawn on the cross-section of the beam tip for the longitudinal vibrations. Therefore, a laser scanning network, with 104 nodes, was drawn on the vertical surface of the actuator beam to measure the transverse vibrations.  
Then, a sweep voltage of 5 V was applied to the piezoelectric stack by a high-speed power amplifier (NF 4010) to drive the actuator. The sweep frequency ranged from 2750 to 6000 Hz. The back mass was fixed by a fixture and the vertical surface of the beam faced the scanning head, as shown in Figure 9. The remaining boundaries were set as free.
# Generic Methodology for Field Calibration of Nacelle-Based Wind Lidars
## 5 LOS Velocity Calibration and Uncertainties
### Calibration Relation  
The calibration relation is a linear least squares regression performed on the binned \(V_{LOS}\) data. A linear regression is first performed on the valid 10-min data in order to visually identify and investigate outliers, if any. The valid data is then binned based on \(V_{LOS}\). The method of bins disregards the quantity of data in each specific bin, and thus allows the fairest comparison between the lidar-measured \(V_{LOS}\) and reference speed \(V_{ref}\). A bin width of 0.5 m\(\cdot\)s\({}^{-1}\) was used, similarly to standard power performance testing. A \(V_{LOS}\) bin was considered valid if it contains a minimum of three data points. Completion criteria of the data collection may typically be that all \(V_{LOS}\) bins between 4 and 12 m\(\cdot\)s\({}^{-1}\) are valid. Indeed, the measurements are performed in uncontrolled conditions. It can thus be time-consuming to fill in the high wind speed bins.  
If the tested lidar performs well, the intercept and slope of the unforced regression are expected to be close to 0 and 1 respectively. **The calibration relation we selected is the linear regression forced to a 0 intercept**. However, both types of linear regression results are valid options for the calibration relation.  
Figure 9 shows the calibration relation results and the regression coefficients of the forced linear regressions. Each LOS of 5B has successively been calibrated. For ZDM, we calibrated \(V_{LOS}\)  
Figure 8: LOS direction evaluation using the RSS process. **Left**: 5B; **Right**: ZDM.  
measurements contained in a 2\({}^{\circ}\)-wide azimuth sector at the bottom of the beam trajectory. A summary of results is provided in Table 1 (see Section 5.7).  
The basic filtering applied seems appropriate: no clear outlier is present in the scatter plots of 10-min data. Note that an analysis of the filters significance is provided in the detailed calibration reports of 5B and ZDM (see [4; 5]). For both lidars, excellent agreement is obtained between binned \(V_{LOS}\) and \(V_{ref}\) with consistent gain values showing a difference between 0.5% and 0.9% with the reference (see Table 1). The observed scatter is low: \(R^{2}\) coefficients are \(>\)0.9998.  
As the LOS velocity calibration is the most important step of the white box concept, the high quality of the results demonstrate the feasibility of the generic methodology to calibrate profiling nacelle lidars.
## 3 Materials and Methods
### Shapley Additive Explanations (SHAP)  
In this study, SHAP was employed to enhance the interpretability of the machine learning model predictions. SHAP is a model explanation framework derived from cooperative game theory; specifically, the concept of Shapley values, which aims to fairly attribute the contribution of each feature to the prediction outcome. By quantifying the marginal contribution of each feature across all possible combinations of features, SHAP provides a consistent and theoretically grounded measure of feature importance [37].  
The SHAP value for each feature represents the average contribution of that feature to the model's prediction, accounting for all possible subsets of other features. This allows for both local (individual prediction-level) and global (dataset-level) interpretability. In particular, tree SHAP--an optimized algorithm for tree-based models such as RF, LightGBM, and XGBoost--enables the efficient and accurate computation of SHAP values. Additionally, SHAP offers a suite of visualization tools--including summary plots, force plots, and dependence plots--that aid in understanding both the magnitude and direction of each feature's effect on the model output [38; 39].  
In the present study, SHAP was utilized to analyze and visualize the relative importance and directional impact of various features in predicting K-VRQOL scores. By applying SHAP values, this study identified which features most significantly influenced individual predictions, thereby improving the transparency of the machine learning models. Furthermore, SHAP analysis enabled a quantifiable interpretation of how pre- and post-therapy acoustic features contributed to quality-of-life outcomes. This provides valuable insights not only for understanding model behavior but also for supporting evidence-based clinical decision-making and developing personalized intervention strategies for individuals with voice disorders.
# Full-Scale Model Test of Subway Contact Channel under Mechanical Construction +
## 6 Conclusions  
In this paper, a full-scale model test of the mechanical connection channel was conducted for the Beijing Rail Transit project. The internal force and deformation laws of the tunnel structure were studied under load-displacement simulation loading control and ground resistance. The main conclusions are as follows:  
(1) In terms of the convergence deformation of the segment structure, the top and waist positions of each ring performed relatively consistently, with the maximum convergence of the top not exceeding 20 mm and the maximum convergence of the waist not exceeding 30 mm. In addition, the variation at the top of the middle three rings was small, whereas the convergence deformation of the waist position of the steel-ring secondary lining composite segment was larger than that of standard rings in the cutting construction.  
(2) In terms of the strain and internal force of the segment structure, the internal force of each ring was redistributed and the axial force decreased overall during the cutting process. The bending moment at the upper spandrel position in the cutting side of the middle three rings decreased significantly with the cutting construction, and the decrement of the bending moment was larger than that of the corresponding axial force. This benefited the stability of the structure. Additionally, the section bending moment near the contraflexure point of the middle three rings changed significantly with the internal support-dismantling process, and it changed from compression to tension conditions. It has been proven that there was a significant bending moment transmission between rings, which also favored the structure stability.  
(3) On the basis of the connection channel full-scale model test, it can be concluded that the mechanical method can be safely and reliably applied in the Beijing Metro construction. Additionally, compared with the existing design schemes of mechanical connection channels, the stiffness of the segment structure and support structure at the cutting position can be weakened, and the stiffness of the steel-ring secondary lining composite segment can be decreased.  
Conceptualization, X.S. and X.Y.; methodology, X.S.; validation, L.F., X.S. and S.
## 6 Opportunities and Future Research Directions
### Routing and Multi-Hop  
Unfortunately, LoRaWAN, the current standard protocol for LoRa, supports only single-packet-at-a-time and single-hop transmission in a star-of-stars topology. LoRaWAN is a medium-access control protocol and does not provide any special support for the transmission of large messages. A star topology is simple and easy to manage. However, it limits the scalability of a LoRa wireless network. Although multiple gateways can be deployed to form multiple star topologies and extend the physical network range, a gateway in a LoRa network requires an Internet connection and has substantially higher cost and power consumption requirements than an end device. Multi-hop image transmission using LoRa is challenging. First, the performance of LoRa has rarely been studied in a wide range of applications, especially large message transmission. Without actual measurements, the feasibility of LoRa being used for large message transmission cannot be confirmed. Second, due to the small maximum transmission unit of LoRa, a large message such as an image must be transmitted using many packets. Such continuous traffic increases not only the network utilization but also the chance of packet collisions. Third, LoRa's low physical layer data rate makes it difficult to broadcast additional data frequently enough to maintain the network topology while performing image transmission tasks, which may lead to serious network congestion or even paralysis. Since there is a huge number of routing protocols proposed in the literature for various ad hoc networking like MANET, VANET, WSN, and WMN. Thus, there is a real need for testing and adopting such protocols for LoRa/LoRaWAN networks to support the multi-hop state of packet transmission and, in addition, to enable communication in the node-node mode instead of node-gateway as in the existing architecture.