esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Methodology
### In-Line Dimensional Inspection
#### 3.2.4 Feature Extraction  
After the mesh registration of \(M\) has been computed, the system proceeds to extract the mesh features required for the dimensional assessment. To compute the revolution axis, we need to first extract the sub-mesh \(M_{bore}\subset M\) which corresponds to the cylindric surface that dictates the rotation of the workpiece. Such cylindric surface has been already identified by the metrologist in the CAD model during the planning phase (Figure 3a). \(M_{bore}\) is computed by extracting the mesh points close to the corresponding CAD feature \(\mathcal{C}_{bore}\):  
\[M_{bore}=\left\{x\in M\quad|\quad d(x,\mathcal{C}_{bore})<\varepsilon\quad \wedge\quad\cos^{-1}(\vec{n}(x)\cdot\vec{u}(x))<\theta\right\} \tag{4}\]  
where \(\varepsilon>0\), \(0^{\circ}\leq\theta\leq 180^{\circ}\) are a threshold distance (mm) and a threshold angle (degrees), respectively, \(\vec{n}(x)\) is the vector normal to the surface at \(x\in M\), and \(\vec{u}(x)\) is a vector pointing to the theoretical revolution axis \(A=(\vec{v},c_{0})\), defined as follows:  
\[\vec{u}(x)=((x-c_{0})\cdot\vec{v})\vec{v}-(x-c_{0}) \tag{5}\]  
The term \(\cos^{-1}(\vec{n}(x)\cdot\vec{u}(x))\) is introduced in Equation (4) to filter mesh noise and improve the estimation of the revolution axis on the scanned mesh. From our experiments, we have found that the threshold values \(\varepsilon=0.5\,\mathrm{mm}\) and \(\theta=10^{\circ}\) produce good results, considering the thermal contraction of the workpiece, mesh noise, etc.  
The vector \(\vec{v}\) is computed by fitting a cylinder to the mesh \(M_{bore}\). The RANSAC algorithm from the Point Cloud Library (PCL) [33] is used to perform the surface fitting.  
An approach similar to the previous one is used to calculate the reference axis point \(a_{0}\). The cone surface feature \(M_{cone}\subset M\) is computed by extracting the mesh points close to the corresponding CAD feature \(\mathcal{C}_{cone}\):  
\[M_{cone}=\left\{x\in M\quad|\quad d(x,\mathcal{C}_{cone})<\varepsilon\right\} \tag{6}\]  
We have found in our experiments that fitting a cone surface to \(M_{cone}\) produces highly unstable results. Instead of fitting the analytical surface, the developed system computes a cylinder \(S_{\vec{v},d/2}\) with axis vector \(\vec{v}\) and cylinder radius \(d/2\). This cylinder is then intersected with \(M_{cone}\), which produces a polyline \(Q\) (Figure 8a). Finally, the intersection between \(\vec{v}\) and the plane that contains the polyline \(Q\) (in a least-squares sense), is the point \(a_{0}\) (Figure 8b).
###### Abstract  
Chronic pain leads to not only physical discomfort but also psychological challenges, such as depression and anxiety, which contribute to a substantial healthcare burden. Pain detection and assessment remains a challenge due to its subjective nature. Current clinical methods may be inaccurate or unfeasible for non-verbal patients. Consequently, Electroencephalography (EEG) has emerged as a promising non-invasive tool for pain detection. However, EEG-based pain detection faces challenges such as noise, volume conduction effects, and high inter-subject variability. Deep learning (DL) models have shown potential in overcoming these challenges by extracting nonlinear and discriminative patterns. Despite advancements, these models often require a subject-dependent approach and lack of interpretability. To address these limitations, we propose a threefold DL-based framework for coding EEG-based pain detection patterns. (i) We employ the Kernel Cross-Spectral Gaussian Functional Connectivity Network (KCS-FCnet) to code pairwise channel dependencies for pain detection. (ii) Furthermore, we introduce a frequency-based strategy for class activation mapping to visualize pertinent pain EEG features, thereby enhancing visual interpretability through spatio-frequency patterns. (iii) Further, to account for subject variability, we conduct cross-subject analysis and grouping, clustering individuals based on similar pain detection performance, functional connectivity patterns, sex, and age. We evaluate our model using the Brain Mediators of Pain dataset and demonstrate its robustness through subject-dependent and cross-subject generalization tasks for pain detection on non-verbal patients.  
pain detection; EEG; neural networks; kernel methods; interpretability; cross-subject analysis +
Footnote †: journal: Applied sciences
# Bending Fatigue Behavior of 17-4 PH Gears Produced by Additive Manufacturing
## 5 Additional Analyses  
Aiming to characterize the gears completely, metallographic observations and fracture surface analysis were carried out on some of the failed teeth. In particular, the crack path was investigated on the A3 tooth: after having cut it along the midplane, the section was mounted in a suitable resin and mirror polished according to the standard metallographic technique. Some porosities were observed on the surface both far from and close to the crack. In Figure 7 some examples are reported. After etching, the melt pools were clearly visible both in the build and in the transversal direction. Figure 8 shows the observed microstructures.  
Figure 6: Quasistatic test results and monoaxial tensile fatigue test results [30].  
Figure 7: Porosities observed close to (**a**) and far (**b**,**c**) from the crack (marked by the arrows in picture (**a**)).  
In Figure 9, the crack path was compared with the tooth microstructural features. It is clearly visible that the propagation direction is not influenced by the melt pool boundaries, but it is instead completely inside the pools.  
The chemical composition of the melt pools was investigated by Energy-Dispersive X-ray Spectroscopy (EDS) analysis as reported in Figure 10 and Table 4. No appreciable difference was detected among the pool center and boundaries.  
Figure 8: Melt pools in the transversal direction (**a,b**) and in the build direction (**c,d**).  
Figure 9: Comparison between the crack path and the microstructure. (**a**) 100 \(\upmu\)m, (**b**) 50 \(\upmu\)m.  
Finally, the fracture surfaces of some of the broken teeth belonging to gears A and B were analyzed by SEM (Figures 11 and 12). The crack origin was often related to surface and subsurface defects related to the production process (lack of fusion and gas porosities). In some cases, nonmelted metallic particles were observed too.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & **AI (\%)** & **Si (\%)** & **Cr (\%)** & **Fe (\%)** & **Ni (\%)** & **Cu (\%)** & **Nb (\%)** \\ \hline A & 0.31 & 0.51 & 17.23 & 74.64 & 3.79 & 3.27 & 0.25 \\ \hline B & 0.28 & 0.47 & 17.1 & 73.15 & 3.76 & 3.30 & 0.24 \\ \hline C & 0.32 & 0.48 & 17.4 & 74.48 & 3.76 & 3.31 & 0.25 \\ \hline \hline \end{tabular}
\end{table}
Table 4: EDS analysis of the melt pool in the zones remarked in Figure 10.  
Figure 11: Tooth A7—the nucleation zone is remarked in (**a**). Surface and subsurface porosities have been observed in the nucleation zone (**b**). The pore diameter is about 40 m (**c**). Close to the surface defects, two smaller porosities are clearly visible; the surface defect is about 50 \(\upmu\)m deep and 60 \(\upmu\)m width (**d**).  
Figure 10: Melt pool SE image.  
In the literature there are several studies about the fatigue behavior of AM parts (e.g., [46; 47; 48; 49]). All of them, even if done on different materials, report that the presence of such defects has a strong influence on the fatigue behavior. These considerations agree with the results coming from the present fatigue campaign.
# Off-Grid Power Plant Load Management System Applied in a Rural Area of Africa
## 6 Experimental Results and Comparison  
We previously built three off-grid solar power plants in different rural areas of Tanzania [1; 5; 17]. Considering that these three off-grid power supply systems need to operate in harsh environments with limited skilled manpower for operation and maintenance, a power plant remote monitoring system was designed and implemented in each village to realize remote data transmission and control from Tanzania to South Korea. According to our previous study, the communication interval between Tanzania and South Korea, i.e., the prediction interval of the predictor, is 15 min [5].  
In South Korea, to ensure the normal operation of these three power plants, three different kinds of power management systems were developed to detect the power usage of each power plant separately in real time. To further discuss the feasibility of each proposed method in future work, all the proposed methods were implemented in the same desktop computer with a 3.4 GHz Intel Core i5 processor, 4 GB RAM, and the Windows 10 operating system [5; 17]. The proposed system in this work was applied to manage the load of the third off-grid solar power plant. The wiring diagram for this village is shown in Figure 5. In each step, if the method finds that the real-time load does not match any learned pattern, a warning will be issued to the manager of the system to remotely control the power plant in Tanzania.  
To comprehensively demonstrate the contributions of this study, the experimental results and comparison sections illustrate and discuss the performance of the proposed method from three perspectives. The experimental results Section 6.1 presents the practical operation process of the method and shows how the proposed method achieves real-time electrical load prediction and high-accuracy anomaly detection. The comparison and evaluation Section 6.2 discusses the effect of the BIC on real-time prediction, the improvement of introducing FOA in the pattern matching process, and the influence of using a variable detection threshold on the detection results. To further evaluate the performance from the perspectives of prediction and detection, in the previous work comparison of evaluation Section 6.3, the proposed system is compared with some advanced methods discussed in the related work section.  
Figure 4: Flowchart of the pattern-matching-based anomaly detector.
## 5 Conclusions  
In conclusion, the present literature review on the thermal management and energy efficiency of 5G antenna network base stations has identified significant gaps, where future research efforts are required. The major identified research gaps are particularly in the fields of the optimization of hybrid cooling systems and in the integration of renewable energy and AI models within 5G and 6G thermal management. This is in addition to the important future role of developing advanced cryogenic cooling systems, enhanced phase-change materials, and the integration of complex thermal-fluid flows and systems (e.g., nanofluids and particulate flows). To overcome the challenges of higher speed rates, inducing higher energy consumption and the overheating of electronic devices, advanced research is required for identifying nd developing improved materials, enhanced thermal management components, and systems including innovative energy-efficient designs. Innovative heat-dissipation solutions are necessary in preventing overheating and ensuring the reliable operation of future antennas and equipment. Energy consumption reduction should be developed in combination with a reduction in operational costs, all while retaining respect for the environment. Future developments should focus on developing both passive and active thermal management methods, accompanied by enhanced antenna designs that will combine the optimal performances, efficiencies, resilience, and sustainability. These should be pursued in balance with the continuous expansion of space markets, which are deploying more and increasingly smaller satellites in outer space.  
Conceptualization, T.D.; methodology, T.D.; investigation, T.D.; original draft, T.D.; review and editing, O.M.; methodology, O.M.; investigation, O.M. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
All data and information are available upon request from the authors.  
The authors declare no conflicts of interest.
## 5 Results and Discussion
### Comparison of Model Results  
The OLS and GWR models were used to predict station ridership using weekday peak-hour inbound ridership as the dependent variable. Due to the different scales of the independent variables and the large quantitative differences between the scales, the independent variables are standardized in this paper to facilitate the comparison of the magnitude of the explanatory impact of the model's independent variables on the dependent variable. The processed results are shown in Table 4.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Variable Type** & **Variable Name** & **Min** & **Max** & **Mean** & **STD** \\ \hline Dependent variable & Y & 44 & 30,355 & 6441 & 5078 \\ \hline \multirow{4}{*}{Independent variable} & \(X_{2}\) & 0.00 & 154,239.00 & 47,452.65 & 25,850.26 \\  & \(X_{6}\) & 4.00 & 4412.00 & 473.26 & 593.65 \\ \cline{1-1}  & \(X_{7}\) & 3.00 & 3008 & 196.19 & 289.95 \\ \cline{1-1}  & \(X_{9}\) & 0.03 & 4.68 & 1.75 & 0.82 \\ \cline{1-1}  & \(X_{13}\) & 23.44 & 83.78 & 34.15 & 12.37 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Descriptive statistics of independent variable dimension.  
Figure 5: Correlation coefficients of independent variables.
# Structural Design and Optimization of Herringbone Grooved Journal Bearings Considering Turbulent
###### Abstract  
In order to improve the performance of the traditional constant-width herringbone grooved journal bearing in a computed tomography tube under a high-temperature environment, the present study designed a convergent herringbone grooved journal bearing (HGJB) structure lubricated by liquid metal. The bearing oil film thickness and the Reynolds equation considering the influence of turbulence are established and solved by using the finite difference method in the oblique coordinate system. The performance of the two bearings was compared, and the static and dynamic performance change trends of the two bearing structures under different eccentricities were systematically studied. The results show that the convergent herringbone grooved journal bearings are superior to the constant-width herringbone grooved journal bearings in terms of bearing capacity and stiffness coefficient. At the same time, the influence of structural parameters, such as the number of grooves, helix angle, groove to ridge ratio, groove depth on the performance of the constant-width herringbone grooved journal bearings, and the convergent herringbone grooved journal bearings was studied. Finally, we conclude that the performance of the convergent herringbone grooved journal bearings is optimal when the number of grooves is 15-20, the helix angle is 30\({}^{\circ}\)-45\({}^{\circ}\), the ratio of the groove to ridge is 1, and the groove depth is 0.02 mm -0.024 mm. This research has provided the thinking and reference basis for the design of liquid metal bearings for high-performance CT equipment.  
liquid metal; convergent herringbone grooved journal bearings; turbulence; structural parameters; static and dynamic performance
# Blockchain's Grand Promise for the Real Estate Sector: A Systematic Review
## 3 Results
### Blockchain Merits in the Real Estate Sector
#### 3.2.1 Blockchain in Land Administration
The trust in the overall land registry system could increase [77], as blockchain could provide a decentralized [74; 96], immutable [25; 42; 74; 77; 78; 97], transparent [67; 74; 77; 76; 97], time-stamped [67; 74; 98], accessible [25; 67; 74; 76; 89; 99; 90; 91; 92; 93; 94; 96; 99; 100; 101; 102], verifiable [25; 42; 69; 74; 78; 89; 96; 103; 104; 105], and up-to-date registration of land records [25; 76; 77; 78; 100; 101; 103] and confirm property ownership [42; 74; 97]. Immutable and decentralized blockchain records could also prevent fraud [12; 25; 36; 42; 89; 90; 98; 104; 106; 107; 108; 109], tampering with records, human errors [31; 67; 78; 81; 90; 110; 111], loss of records [78; 112], tax evasion [86], and corruption [29; 31; 67; 69; 77; 111; 112]. Thus, blockchain land records could also protect and enforce property rights [74; 77; 83; 96; 113], especially in developing countries [70; 80; 110; 114]. Despite the many potential pros, applying blockchain in land registries remains challenging due to legal, implementation, and technical reasons. First, implementing blockchain within land administration requires good-quality digitalized data [12; 96; 115]. Overall, blockchain seems unable to resolve the primary land administration challenge in many emerging economies: how to initially bring citizens and properties into the formal land registry system [13; 15; 80]. The technical difficulties of blockchain land administration include public-private key administration and potential loss of keys [51; 67; 78; 96; 115; 116], transaction speed [96; 117], interoperability [78; 96; 117], scalability [13; 15; 18; 31; 77; 117], and long-term data preservation [51; 116]. Although blockchain systems are often justified as more secure than traditional systems, they also face cyber threats [51; 116]. Legal recognition of blockchain-based land registries, in general, would require updating the current legislation [70; 96; 118; 119; 120] and standardization [15; 42; 96]. These changes would require political will [120]--a chal lenge, especially in countries whose corrupted public administration benefit from current non-transparent systems [29, 31, 85]. In addition to governmental support, implementing blockchain land registries requires collaboration with many stakeholders [96] and changing current processes [59]. Last, some have questioned whether centralized \"permissioned\" blockchains provide any benefits over traditional centralized governmental registries that governments have used for land registry purposes for decades [57, 91].
## 2 Theoretical Foundation and Hypotheses Development
### Economic Factors
#### 2.4.2 Human Development and Currency Reserve  
The human development index is a statistical index that combines data on per capita income, education, and life expectancy. A country's HDI score is influenced by factors such as a longer life expectancy, higher levels of education, and higher gross national income (PPP) per capita. Technology adoption rates are more rapid in nations with high per capita income [49]. Human development has been extensively researched and is considered crucial to a country's ability to absorb new technologies and to technologically advance [49; 63]. [PERSON] [63] found that the level of education is crucial in influencing how quickly information and communication technology advances in nations.  
Foreign exchange reserves are another crucial economic component in accelerating the implementation of innovation and facilitating international trade ties. Different nations have distinct demands for foreign currency reserves based on their income levels [64]. While low-income countries retain reserves for transactional purposes, higher-income nations do so for speculative motives [65]. Owing to trade deficits and imbalances, low-income countries must maintain a certain amount of foreign exchange reserves to satisfy imports [65]. Numerous studies suggest that CBDCs could help central banks set up a different cross-border payment system [13]. Countries with low foreign reserves may be interested in exploring earlier ways to adopt central bank digital currencies as a faster and more effective means of increasing remittances and international trade. Thus, we propose the following hypotheses:  
**H9.**_Human development is positively associated with a country's central bank digital currency adoption._  
**H10.**_Currency reserves are negatively associated with a country's central bank digital currency adoption._
## 2 The Laboratory Setup  
The employed laboratory setup is presented in Figure 1. It consists of a light-weight active casing placed in the corner of a room and the appropriately arranged microphones: one reference microphone, five error microphones and four room (monitoring) microphones.  
The active casing is placed in the corner with its back and right panels. It is built of five steel plates (1 mm thick) bolted together, forming a cuboid of dimensions 630 mm \(\times\) 800 mm \(\times\) 500 mm. The active casing is placed on a sound-insulating basis. Inside the casing, a loudspeaker is placed and it is used for the generation of a primary noise. The loudspeaker as a noise source provides a more reproducible environment for control system evaluation as compared to a real device (which is also examined in other studies performed by the authors). The employed active casing itself is described in more detail in [12; 14; 15]. It is important to emphasise that such a construction of the casing is very challenging from the control point of view. The casing panels are connected to each other directly without using any rigid explicit frame, and such mounting of their edges leads to both vibrational and acoustical couplings between them.  
Near the loudspeaker inside the casing, a reference microphone is placed to obtain a reference signal. It can provide information about the primary noise. Five error microphones are placed around the active casing at specific positions, described in detail in Section 3. There are also four room microphones, which are used to evaluate the noise reduction performance (they are not used by the control system). The room microphones are placed in four arbitrarily selected irregular locations in the enclosure, at greater distances from the casing. Each position corresponds to a possible location of a listener [16].  
To control vibrations of the active casing, inertial mass actuators EX-1 are used. They are light-weight (115 g) actuators of small dimensions (diameter 70 mm), compared to the size of the casing. They are attached to the inner side of the casing panels. In total, 21 actuators are used (5 actuators are attached to the top panel, 4 actuators are used per each of the remaining panels). The number of actuators and their placement is a result of analysis and optimization process maximizing a measure of the controllability of the system [15].