esa-sceva/satcom-chunk-collection huggingface dataset:
# Sparse Envelope Spectra for Feature Extraction of Bearing Faults Based on NMF
## 4 Conclusions  
In this paper, based on the non-negative matrix factorization of the time-frequency distribution of periodic transient oscillations, we propose feature extraction for the characteristic frequencies of rolling bearing faults, which takes into account the non-stationary characteristic of impact excitation for localized faults. The application of simulations and experiments shows that, based on time-frequency distribution, non-negative matrix factorization not only decomposes the frequency band adaptively, but also extracts the time domain envelope of the signal of the corresponding frequency band. Using the inner product of the band-pass filtering and time weight envelopes, the sparse envelope spectrum is realized to enhance the fault-related frequency component. Thus, the strict requirements of band-pass filtering on the position and bandwidth of the filter band are reduced. Compared with band-pass filtering and fast spectral kurtosis methods, the weak fault-rated features are easier to observe in the sparse spectrum. In practice, the running speed of many pieces of equipment, such as a wind-powered gearbox, is not stable. Therefore, fault feature extraction under variable speed is the work of further research.  
Conceptualization, L.L., G.H. and L.S.; Methodology, L.S.; Software, B.N.; Validation, L.F., L.S. and B.N.  
This research was funded by the National Natural Science Foundation of China (Grant 51575438), the China Postdoctoral Science Foundation (Grants 2017M623159 and 2018T111046), the Postdoctoral Science Foundation of Shaanxi Province (Grant 2017 BSHEDZZ68), and the Fundamental Research Funds for the Xi'an Jiaotong University (Grant XJ2018047).  
**Acknowledgments:** We thank all reviewers and editors for their helpful comments and suggestions.  
Figure 22: Fault characteristics extracted by fast spectral kurtosis method: (**a**) Kurtogram of the simulated signal, the global maximum is achieved for \(f_{c}=6400\) Hz and Level = 3.6; (**b**) Waveform of the filtered signal; (**c**) Spectrum of the filtered signal; (**d**) Envelope spectrum of the filtered signal.
# Design and Experiment of Magnetic Antenna Vibration and Noise Reduction System
## 3 Analysis and Design of Damping System
### Principle Model of Vibration Damping System and Matching Analysis of Main Parameters
\[f_{\mathrm{n}}\leq f_{\mathrm{c}}/\lambda_{\mathrm{m}} \tag{19}\]  
Considering the high requirements for damping performance in the concerned frequency band, based on engineering practice experience, it is proposed to design the antenna damping system as a small damping rate system with \(\zeta\leq 0.05\). Combined with \(\gamma=100\), it can be concluded that \(\lambda_{\mathrm{m}}\geq 12.78\). Therefore, the natural frequencies of the radial translation and pitch and yaw modes of the antenna damping system must satisfy that \(f_{\mathrm{n}}\leq 4.7\) Hz. Combining Equation (15), it can be seen that in order to achieve the desired damping performance, the maximum radial stiffness of the antenna damping system must meet the following conditions:  
\[k_{\mathrm{trans}}=\max(4{K}{S_{\theta}}^{2}+k_{G},4{K}{C_{\theta}}^{2})\leq \min(\frac{4\pi^{2}mf_{\mathrm{c}}^{2}}{\lambda_{\mathrm{m}}^{2}},\frac{4\pi^{ 2}lf_{\mathrm{c}}^{2}}{\lambda_{\mathrm{m}}^{2}L^{2}})=\frac{4\pi^{2}lf_{ \mathrm{c}}^{2}}{\lambda_{\mathrm{m}}^{2}L^{2}} \tag{20}\]When the stiffness and damping rate parameters for matching are selected in the lower left field of the curve, the vibration damping performance can be guaranteed to meet the index requirements. Obviously, the stiffness \(k\) of an elastic element is closely related to its length \(l\), section characteristic dimensions (such as cross-sectional area \(s\)), and material mechanical properties (such as Young's modulus \(E\)). In this scene, the inclination angle \(\theta\) of the elastic element not only affects its length \(l\), but also affects its stiffness distribution in the vertical and horizontal directions, which is the key optimization parameter for the detailed design of the next step.
# Behavioural Realism and Its Impact on Virtual Reality Social Interactions Involving Self-Disclosure
## 1 Introduction
### Motion-Captured Avatars and Their Impact on VR Social Interactions  
Avatars with motion capture have face and body movements that may be perceived as highly lifelike [24; 25; 26; 27; 28]. Motion is captured via sensors attached to the body or via camera footage that can be broadcast onto an avatar in real time [11; 22; 23; 29; 30]. This offers a responsiveness that is superior to computer-scripted or pre-recorded animations [31; 32; 33; 34; 35]. Several studies have revealed that realistic facial gestures and body gestures for avatars may enhance user perceptions of trust, likability, and satisfaction during VR social interactions [27; 30; 36; 37].  
Many metaverse social VR platforms (e.g., Horizon Worlds, BeanVR, VRChat, Rec Room) use avatars with limited behavioural realism in terms of expressions, gestures, and body language. This could be a deliberate choice, as maintaining a high level of accessibility to their product is a core concern. Most social VR platforms only incorporate basic motion tracking features, such as head and hand tracking, with some including additional features, like eye tracking. Previous studies have revealed that many users prefer avatars with stronger behavioural realism [22; 23; 29; 38]. However, it remains unclear whether current social VR platforms would benefit from increased behavioural realism in their avatars due to limited research in this area. Comparing avatars with full-body motion capture with the type of avatars used in many metaverse social VR platforms will help to clarify if introducing higher levels of behavioural realism may help to improve feelings of comfort and enjoyment [22; 23; 24; 39].
## 3 Results
### Analysis of Ionospheric DVTEC Disturbances
#### 3.2.1 DVTEC Variations Due to Thunderstorms
In this time interval, peak-to-peak DVTEC amplitude values of up to 0.67 TECU were observed. In Zone 1, the peak-to-peak DVTEC amplitude maxima surrounded the storms, while, in Zones 2 and 3, the maxima were generally located in the western region of the country. Recall that, for this time period, the storm was in its growth phase. From 02:40 UTC-05:20 UTC (i.e., 23:40 LT-02:20 LT), a predominance of peak-to-peak DVTEC amplitudes between 0.44 TECU and 0.67 TECU was observed in all three zones. Average peak-to-peak DVTEC amplitudes of 0.61 TECU, 0.65 TECU, and 0.57 TECU were obtained for Zones 1, 2, and 3, respectively. Peak-to-peak DVTEC amplitude values of up to 1.11 TECU were observed for Zone 1 and 1.35 TECU for Zones 2 and 3. These maxima were located, for Zone 1, mainly between the storms (Figure 11), while, for Zones 2 and 3 (Figures 12 and 13), they were located over the mountain range. In this time period, the storms were in their development-maturity phase. Figure 12: Same as Figure 11, for RAMSAC stations in Zone 2. Figure 13: Same as Figure 11, for RAMSAC stations in Zone 3. Finally, in the time interval 05:20 UTC-08:00 UTC (02:20 LT-05:00 LT), peak-to-peak DVTEC amplitude values of up to 0.67 TECU were observed, mainly located in the northern region of the country. Likewise, a predominant peak-to-peak DVTEC amplitude between 0.21 TECU and 0.44 TECU was observed. An average peak-to-peak DVTEC amplitude of 0.25 TECU for Zones 1 and 3 and of 0.3 TECU for Zone 2 were also observed. During this time period, thunderstorm electrical activity was decreasing.
# Combined Channel Estimation with Interference Suppression in CPSS
## 6 Conclusions and Future Work  
This study proposed a novel channel estimation with interference suppression, which used machine learning to meet the requirements of CPSS in complex electromagnetic environments.  
The \(K\)-means algorithm was used for interference detection in CIR of frequency domain, and suppressed the interference with linear interpolation of interfered subcarriers. The KNN algorithm was used for noise cancellation in the CIR of time domain, which is close to Bayes probability of error. Both \(K\)-means in CIR of frequency domain and KNN in CIR of time domain have relatively lower complexity in channel estimation, which are compliant for nodes in CPSS. Using extensive simulations, the performance of the proposed scheme is proven superior to the traditional scheme. The proposed scheme is proven to work effectively in an interference scene and the negative effects of transmission in interference are under control.  
Our future work will focus on the implementation and optimization of the scheme, hopefully helping to improve the transmission stability and reliability in CPSS.  
**Author Contributions**: Formal analysis, X.L.; Resources, X.L.; Software, H.W.; Writing--Original Draft, H.W.; Writing--Review and Editing, X.L.  
**Funding**: This research received no external funding.  
**Conflicts of Interest**: The authors declare no conflict of interest.
## 4 Methodologies and Implementation
### Challenges and Limitations in Implementing DDPM for Biomedical Image Segmentation
#### 4.3.8 Real-Time Constraints  
Biomedical applications often require real-time or near-real-time processing, especially in clinical settings. DDPM's computational demands may hinder its feasibility for applications with stringent time constraints [105; 106].
## 5 Simulation Results
### Ergodic Rate  
Figure 4 illustrates the simulation results with \(\delta=[90,105]\) dB. Specifically, the length of selection time-slot is set as \(\tau=1\) ms and the power factor is \(\alpha=0.4\). It can be clearly noticed that the curves of analytical expressions closely follow with the numerical simulations. Since signals for a beam-edge UT and \(M\) beam-center UTs can be transmitted simultaneously in the co-carrier-based DC method, we can expect a more promising ergodic sum-rate compared with the co-carrier-based SC method. For the beam-edge UT, we can find out that the co-carrier-based DC scheme outperforms the co-carrier-based SC method in the low SNR region. However, the result of co-carrier-based SC method approaches that of DC when the channel becomes better. Moreover, the ergodic sum-rate or the rate for beam-edge UT could be improved by using either method compared with a non-cooperative strategy.  
To see how the co-carrier-based SC method behaves with a selected time-slot, we provide the results with \(\tau=10\) ms. It is noteworthy that the advantage of co-carrier-based SC fades away with the growing time-slot shown in Figure 5. That is, the higher transmission rate is beneficial to the co-carrier-based SC method.  
Figure 4: Ergodic sum-rate/rate with \(\tau=1\) ms and \(\alpha=0.4\).  
Figure 5: Ergodic sum-rate/rate with \(\tau=10\) ms and \(\alpha=0.4\).  
Figure 6 illustrates the ergodic rates with \(\alpha=0.2\). That is, the signal power for beam-center UTs lowers while the interference for beam-edge UTs reduces as well. It is observed that the performance of the co-carrier-based DC degrades significantly since there exist \(M\) beam-center UTs in each transmission slot. We can clearly find out that the ergodic rate for the beam-edge UT in both methods increases compared with the result in Figure 4. Additionally, the ergodic sum-rates of co-carrier-based SC and non-cooperative transmission also degrade under the influence of lower power factors.  
Figure 7 shows the results of ergodic rate with more visible satellites where \(M=9\). It can be noticed that the ergodic sum-rate of the co-carrier-based DC could be significantly improved since more simultaneously served beam-center UTs are involved. In addition, the ergodic rate of the beam-edge UT also increases since more signal paths are received at the UT. Note that there is no noticeable performance improvement for the co-carrier-based SC method.
## 2 Materials and Methods
### Data Acquisition and Integration  
To support real-time data acquisition in the pilot project, a custom data pipeline was developed by integrating multiple existing and purpose-built components. The company's Enterprise Resource Planning (ERP) system provided information on production orders and routing. At the same time, Microsoft Excel365 (Version 2406, Build 17726.20126), enhanced with Visual Basic for Applications (VBA) macros, was used for manual input and structured formatting. A custom-developed API enabled live data collection from shop-floor terminals and edge devices directly from workstations. All collected data were then centralized and visualized within the DIMUSA platform, serving as the primary hub for both monitoring and analysis. The data captured through this system included the order number, product ID, workstation identifier, and precise timestamps marking the start and end of operations. In cases of interruptions or abnormal events, operators manually entered reason codes and additional contextual information. These structured and timestamp records provided the analytical foundation for performance evaluation and cluster-based analysis in the subsequent stages of the project. Figure 4 illustrates the  
Figure 3: Screenshot of the virtual factory simulation model created in Siemens Plant Simulation to validate data patterns and test production improvement scenarios.  
interface of the DIMUSA system platform, which is used for live monitoring and manual input. The dashboard enabled operators and supervisors to track production progress, identify and visualize the bottlenecks, and contribute relevant context during exception events, enhancing both traceability and interpretability throughout the system.
# A Local Feature Engineering Strategy to Improve Network Anomaly Detection +
## 3 Background
### Intrusion Detection Systems
#### 3.1.3 Network Attacks  
To place the appropriate countermeasures against the potential network attacks, the researchers need detailed knowledge of techniques, strategies, and tools used by the attackers. Such information is easily available, as it is usually in the public domain. On the basis of their behavior and potential impact on the attacked resources, Table 2 groups the most common ones into several classes.  
Figure 4: IDS network-node-based modality.  
Figure 3: IDS network-based modality.  
The aforementioned classes of attacks are exploited in order to conduct dangerous well-known attacks such as SYN flooding, IP spoofing, session hijacking, man-in-the-middle, DHCP starvation, and many more [77]. It should be underlined that their intrinsic dangerousness arises from the fact that many of these attacks do not require any in-depth expertise, since they can be conducted using tools easily available on the Internet [78]. By exploiting such tools, people can perform a number of dangerous activities without particular efforts, from those related to the information discovering to those aimed to the exploitation/block of network resources. In addition, the possibility to operate these attacks both by using wired and wireless networks [79], makes it even more difficult to identify those responsible for the attacks.  
It can also be observed that many common instruments/tools, which are not precisely classified as attacks, are able to perform crucial operations in an attack context. Some significant examples are simple commands such as ping, fping, arping, and traceroute and more sophisticated tools such as EtherApe [80], able to perform network traffic sniffing [69]. An interesting investigation about the deep-learning techniques used in order to perform automate security tasks such as the malware analysis was presented by [PERSON] and [PERSON] [81].
## 6 Conclusions and Future Directions
### Main Conclusions
#### 6.1.2 Technical Innovations Hold Significant Value  
This study achieved technical innovations in multiple aspects, which not only solved specific technical problems but also provided new perspectives for related field development:  
The trajectory point-labeling algorithm based on polygon coverage represents an innovation of this paper. This algorithm cleverly transforms the continuous trajectory discretization problem into geometric containment relationship determination, improving computational efficiency while ensuring identification accuracy. Compared with traditional map-matching algorithms, this method does not require detailed road network topology information, lowering application barriers. The algorithm demonstrates good interpretability and stability, performing excellently in practical engineering applications.  
The systematic methodological framework represents another innovation. This study proposes, for the first time, a complete parameter extraction process oriented toward signal control optimization, from data preprocessing to feature extraction, from microscopic trajectories to macroscopic parameters, with each step carefully designed. This solution avoids disconnection between different processing stages, improving overall efficiency. The framework's modular design provides good scalability, easily adapting to different application requirements.  
The concept of multi-source data fusion permeates the entire study. Employing multiple methods in parameter calculation and fusing results not only improves estimation accuracy but also provides inherent quality control mechanisms. This concept has universal significance and can be extended to other types of traffic data analysis.
###### Abstract
[35] explored seismic control and found that periodic barriers exhibit better isolation effects on longitudinal and transverse waves than empty trenches, with higher isolation efficiency observed when closer to the vibration source. In summary, on the one hand, research on the vibration control of DC has mainly focused on the vibration response of the soil behind the trench and has not addressed the vibration control of structures, especially large structures such as dikes. On the other hand, these studies have rarely treated the foundation as a multi-layered soil structure, which does not reflect reality. Based on the limitations of previous studies, this study employs a combination of field testing and numerical simulation to investigate the spatial attenuation characteristics of the ground vibration response caused by the waves of DC in a typical multi-layered alluvial soil foundation adjacent to the Yangtze River. This study takes into account the multi-layered structure and material nonlinearity of the soil and evaluates the vibration isolation effect of different depths and locations of isolation trenches through a controlled experiment at a fixed distance between the vibration source and the protected object. The findings of this study provide effective guidance for the design of isolation trenches used in vibration control in similar processes of DC. The remainder of this paper is organized as follows: Section 2 introduce the site conditions and experimental arrangement, respectively. Section 3 analyzes and discusses the results of the field experiment. Section 4 describes the numerical simulation of the site and analyzes the simulation results in light of the field experiment. Finally, Section 5 summarizes the study's main findings.
# Mobile Network Operators' Assessment Based on Drive-Test Campaign in Urban Area for iPerf Scenario
## 6 Summary  
In this paper, we analyzed the QoS metrics and reference signal parameters used in LTE and 5G for the iPerf scenario, which were obtained in the drive test campaign conducted by Systemics-PAB in the urban area for four Polish MNOs. These measurement data were the basis for the correlation analysis performed for TCP and UDP, and UL and DL. Based on PCC, we selected the best signal parameters that can be used to estimate throughput for TCP/UDP, and jitter only for UDP. In this regard, we propose to use RSRP for UL and SINR for DL. In terms of assessing the relationship between radio signal metrics (i.e., RSRP and SINR), we find that these metrics are independent of the provided services and can generally be analyzed independently of the MNO. Only the Plus for the relationship between RSRP-5G and SINR-5G is characterized by a certain deviation.  
On the other hand, analyzing the relationship between RSRQ-5G and SINR-5G makes it possible to identify MNOs based on averaged measurement data and reflects their KPIs in a broader scope. The analysis of the measurement results confirmed that the use of the same RAN contributed to a very similar QoS assessment for two MNOs, i.e., Orange and T-Mobile. On the other hand, the additional use of the 40 MHz band at the 2.6 GHz band by Plus for the needs of the emerging 5G NR network allowed for higher RSRQ-5G and significantly greater throughput for DL. The remaining MNOs do not have radio resources in this frequency band. Before the auction for the C band, these MNOs (i.e., Orange, Play, and T-Mobile) could only use bands typical for LTE or older generations (i.e., 900, 1800, 1900, or 2700 MHz) for the 5G NR network. This approach is possible thanks to the principle of technological neutrality.  
In the near future, the authors plan to analyze other scenarios for QoS tests in Polish mobile networks.  
Conceptualization, D.Z. and J.M.K.; methodology, D.Z. and J.M.K.; software, D.Z. and J.M.K.; validation, D.Z.; formal analysis, D.Z. and J.M.K.; investigation, D.Z.; resources, D.Z.; writing--original draft preparation, D.Z. and J.M.K.; writing--review and editing, D.Z. and  
Figure 25: Similarity assessment of PCC heatmaps for the MNOs, TCP and UDP.  
J.M.K.; visualization, D.Z. and J.M.K.; supervision, J.M.K.; project administration, J.M.K.; funding acquisition, J.M.K. All authors have read and agreed to the published version of the manuscript.  
This work was financed by the Military University of Technology (WAT) under project no. UGB/22-863/2023/WAT on \"Modern technologies of wireless communication and emitter localization in various system applications\".  
Not applicable.  
The data presented in this study was provided by the Systemics-PAB company. The authors are not authorized to provide them.  
The authors would like to thank the Systemics-PAB company for providing the measurement data.  
The authors declare no conflict of interest.