esa-sceva/satcom-chunk-collection huggingface dataset:
# 4D-Flow MRI Characterization of Pulmonary Flow in Repaired Tetralogy of Fallot
## 4 Discussion
In our study, maximum and average PD were significantly higher in the PA of the rTOF. There is limited literature on the assessment of 4D-flow-based PD along the PA in the rTOF. However, extensive literature exists in the context of aortic valve disease and aortopathies [25; 26; 27]. PD is a familiar measure for clinicians as the concept aligns with Doppler echocardiography assessment. A particular detail in the evaluated rTOF cohort was the consistent PD elevation along the PA. The LPA PD was found to be the higher for all analysis planes. The latter may be due to stenosis branching that is recurrent in rTOF patients. Another interesting aspect of our study was the evaluation of EL. Energetic expenditure can provide insightful information about the hemodynamic performance and load coupling with the RV. As expected, the rTOF had a significant expenditure of EL in the PA. Other studies have explored the energetic cost of using kinetic energy instead of EL. [PERSON] et al. also demonstrated an increase in kinetic energy along the MPA in the rTOF as compared to controls across the cardiac cycle with a \(p\)-value \(<\) 0.01 [28]. However, important differences exist between kinetic energy and EL. Kinetic energy is given by 0.5\(\times\)\(mV^{2}\), where \(m\) is the mass and \(V\) is the velocity. Kinetic energy represents the energy of an object because of its motion. EL basically reflects the viscous energy dissipation [29]. In our study, EL was found to be associated with pulmonary peak velocity, which is expected as peak velocity increasing the energetic dissipation. One of the novel findings of this study was the assessment of VFA. Delayed ejection and retained inflow were able to characterize the intra-cardiac hemodynamic characteristics of rTOF patients. In addition, both parameters were associated with ventricular volumes and EF. The latter provided new information about the performance of the RV. As the baseline measurements indicated, it was a small impairment of the RV function. It was mostly identified by the RVEF. Both FVA components (delayed ejection and retained inflow) showed a better discrimination of RV performance than RV volumes and detected differences were higher than RV EF. Unfortunately, there is a limited literature on VFA in the rTOF. The main limitation of this study was the cohort size, which included a total of \(n=37\) subjects. Another limitation was that a single investigator performed the data analysis. In this study, the age at surgical repair was not considered as a determinant factor for altered hemodynamics given that it was not possible to evaluate if it had an impact on adult hemodynamics. The age difference between controls and patients is also an important limitation of the study, as age and sex matching were not considered during recruitment. The presence of angular variations between the RVOT and the MPA and assessment of wall thickness were not evaluated. Despite this limitation, results showed clear differences and associations between the cohorts and evaluated parameters.
# Broadband DOA Estimation by Exploiting DFT Extrapolation
## 3 Simulation Results  
### Simulation Conditions  
An antenna array of 12 elements was designed at 3 GHz, and the uniform interval between elements was set to be half wavelength. The 12-element antenna array was virtually extended to 36 elements using DFT extrapolation. Twelve virtual elements were added to the left and right sides of the real array. The DOA was randomly chosen, and the number of sources was three, four, or five. We assumed that the signal from the DOA was sampled under 10 dB and 20 dB SNR, where the noise followed a Gaussian distribution, which was calculated using the average of the absolute values of the sampled signal. Given that the SNR of the sampled signal can be improved with a multi-snapshot when it comes to a lower SNR [16], the simulation was performed only under the aforementioned two SNRs. The number of spectral samples \(M\) was fixed at 1024 to achieve a high resolution of the DOA estimation results from each array. The frequency band observed was from 500 MHz to 3 GHz with a step of 0.1 GHz. The hyperparameter \(\lambda\) and tolerance were heuristically set to 0.003 and 0.01, respectively, throughout the frequencies.  
To observe the improvement of the DFT extrapolation, we compared the estimation of arrays with virtual arrays with the estimation results using the real array before the extension and the real array with the same number of elements as the virtual array: (1) a real array with 12 elements, (2) a 12-element real array extrapolated to 36 elements, and (3) a 36-elements real array. Assuming that we already know the number of DOA, the root mean square error (RMSE) value was used as a metric to evaluate the DOA estimation result, which was obtained by averaging 1000-times repeated results at each frequency [17]. If the estimated DOA number was less than the real DOA, we set the RMSE to 45\({}^{\circ}\). To determine the correlation between the estimated DOA number and RMSE, we plotted the average number of peaks greater than \(-15\) dB in the normalized pattern in the spectral domain for each frequency.
## 3 Experimental Results and Discussion
### Energy Dissipation
It is found that for each specimen in Figure 7a, the total input strain energy density increased linearly until the strain reached approximately 0.005; then it turned into nonlinearity. The maximum total input strain energy densities varied between \(0.224\times 10^{3}\) J/m\({}^{3}\) to \(0.296\times 10^{3}\) J/m\({}^{3}\). In Figure 7b,c, it is observed that the mean value and the STD, of the maximum input strain energy density are  
In Figure 8a, it is found that the curves of the elastic energy density for CA mortar specimens are similar to the stress-strain curves. In detail, during the early loading stage, the elastic strain energy densities linearly increased until the stress reached 80% of the peak stress, then the growing rates began to decrease. The maximum elastic strain energy densities varied between \(0.027\times 10^{3}\) J/m\({}^{3}\) and \(0.049\times 10^{3}\) J/m\({}^{3}\). In Figure 8b,c, the maximum mean elastic strain energy density is 0.036 with a corresponding strain of 0.0066. The STD. of the elastic strain energy densities for CA mortar specimens first increased to \(0.0025\times 10^{3}\) J/m\({}^{3}\) at the point of 80% of the peak stress approximately. Then it went up to the maximum value of \(0.0094\times 10^{3}\) J/m\({}^{3}\) and decreased at a comparatively slowly rate to \(0.00207\times 10^{3}\) J/m\({}^{3}\). Figure 7: Total input strain energy of CA mortar specimens: (**a**) Total input strain energy of CA mortar specimens; (**b**) Mean and STD of total input strain energy; (**c**) Mean \(\pm\) STD of total input energy. In Figure 9a, the curves of dissipated strain energy densities for CA mortar specimens are similar to the total input strain energy density curves. The final values for the dissipated strain energy densities ranged from \(0.219\times 10^{3}\) J/m\({}^{3}\) to \(0.286\times 10^{3}\) J/m\({}^{3}\). It is observed that in Figure 9b,c, the maximum mean dissipated strain energy density is \(0.238\times 10^{3}\) J/m\({}^{3}\) with a corresponding STD. of \(0.018\times 10^{3}\) J/m\({}^{3}\). Figure 8: Elastic strain energy of CA mortar specimens: (**a**) Elastic strain energy of specimens; (**b**) Mean and STD for elastic strain energy; (**c**) Mean \(\pm\) STD for elastic strain energy.
## 5 Conclusions  
According to a 500 kV transmission line practical engineering example, a three-dimensional finite element model of the power transmission tower is established. The PTMD is simulated in ABAQUS. The vibration reduction mechanism of PTMD is introduced. The response of the transmission tower with a TMD and PTMD are performed, respectively. Based on the above analysis results, the following conclusions are drawn:  
1. Compared with the TMD, the PTMD is more effective in reducing the vibration of a transmission tower under multi-component seismic excitations. The vibration reduction ratios of the transmission tower with PTMD are varied with different seismic waves.
2. The reduction ratios of the transmission tower with PTMD in the longitudinal and transverse directions have the same trend with the increase of mass ratio until 2%. The mass ratio of 2% is the optimal result.
3. The reduction ratios of the transmission tower with the PTMD in the longitudinal and transverse directions decrease with the increase of the ground motion intensity, but the ground motion intensity has an insignificant influence on the reduction ratio.
4. The reduction ratio of the transmission tower with the PTMD in the longitudinal and transverse directions increases first, and then decreases with the increase of the gap. The influence of the gap on the control effect of the PTMD is not significant.
5. The reduction ratio in the longitudinal direction increases gradually with the increase of the incident angle. Compared with the reduction ratio in the longitudinal direction, the trend of the reduction ratio in the transverse direction is just the opposite. The incident angle has a significant influence on the reduction ratio.  
**Acknowledgments:** This study were financially supported by the National Natural Science Foundation of China (No. 51578325 and 51208285), and Key Research and Development Plan of Shandong Province (No. 2016 GXG104008).  
**Author Contributions:** [PERSON] and [PERSON] did the modelling work, analyzed the simulation date and wrote the paper. [PERSON] and [PERSON] revised and checked the paper.  
**Conflicts of Interest:** The authors declare no conflict of interest.
# The Role of Platelet-Rich Plasma in the Management of Ankle Osteoarthritis: A Systematic Review
## 3 Results
### PRP Effectiveness  
Pain and function measures were included in all the selected studies. Pain was measured by using the Visual Analogue Scale (VAS) [19; 20; 21; 23] and sub-scores from VAS Foot and Ankle (VAS-FA) [22], Ankle Osteoarthritis Score (AOS) [23], and Japanese Society for Surgery of the Foot (JSSF) [21]. Function was assessed with the Foot and Ankle Disability Index (FADI) [20], AOS [19], Ankle Activity Score (AAS) [19], Foot and Ankle Outcome Score (FAOS) [19], Single Leg Stance (SLS) test [23], and American Orthopaedic Foot and Ankle Score (AOFAS), and sub-scores from VAS-FA [22], AOFAS [19; 23], and JSSF [21]. Secondary outcomes such as quality of life, satisfaction, achieved goals, and pathological condition of the foot and ankle were measured by using Short-Form 36 (SF-36) [19; 22], the EuroQol Quality of Life questionnaire (EQ-5D-3L) [19], Goal Attainment Scaling (GAS) [19], the Self-Administered Foot Evaluation Questionnaire (SAFE-Q) [21], and a global satisfaction score [23].  
Overall, all of the studies showed significant results for pain and function measurements during and at the end of the different follow-up periods. However, one study divided the patients into two sub-groups regarding the stage of OA, and the results differed among them. The subjects suffering from early-stage OA had significantly better results in VAS and JSSF data in comparison with later-stage individuals (\(p\) = 0.02) [21]; concerning within-group evaluations, significant results were observed for VAS in the early-stage group (\(p\) = 0.01) and for JSSF in the late-stage group (\(p\) = 0.005) at 1-month follow-up; regarding the 3-month follow-up, the VAS and JSSF scores improved significantly in both early- and late-stage groups, although they did not persist over time. Another study did not show intra-group details from the different follow-ups, but these were significant between baseline and 26-week measurements in both groups (\(p\) < 0.001); nevertheless, no significant changes between groups were found [19].  
Regarding secondary outcomes, one study showed significant improvements for SAFE-Q at 3 months through overall assessments, although these were not present when evaluating early- and late-stage subjects separately [21]. Another study divided subjects into two groups to determine the satisfaction with the results, and those in the satisfied group reported higher SF-36 scores than those belonging to the unsatisfied group (\(p\) = 0.003), in the same vein as that which occurred with the VAS-FA [22]. In this manner, [PERSON] et al. also assessed patients' satisfaction and found higher improvement rates in those who were more satisfied [23]. [PERSON] et al. also registered patients' degree of conformity in their study and found that 80% of the subjects were satisfied and returned to their previous level of activity [20].  
Table 5 shows further details about the studies' reported outcomes.
## 5 Security Model Requirement  
As concluded in Section 2, although some good achievements have been obtained in terms of integrity and authentication, existing security models for code updates in WSNs are lacking some critical requirements, like availability or confidentiality. As a result of studying all these protocols, we have identified a list of security considerations (Table 2) in designing a secure protocol. In the case of an over-the-air programming scheme for WSNs, it is necessary to make sure that it is robust against all possible attacks and that all the security principles are preserved. It is mandatory to implement these prerequisites in the design of the OTAP scheme. A review on how this model secures OTAP schemes can be found below:  
**Confidentiality:** For confidentiality preservation, symmetric cryptography (e.g., AES) has very less energy consumption compared to public key cryptography algorithms [26] (e.g., RSA). Furthermore, storing a symmetric key on each node is not a wise idea, because an attacker can easily obtain it in the case of a non-tamper-proof device. Therefore, for confidentiality preservation, it is suggested to use symmetric cryptography. A symmetric key needs to be avoided from being written on the EEPROM of nodes for further use, and instead, this key has to be unique and new for each communication link and must be generated so that it is authentic. For the sake of simplicity, we refer to this temporary key as the session key. In our protocol, the elliptic curve Diffie-Hellman (ECDH) key exchange method [27] is used, and the authenticity of the generated session key is guaranteed using signature verification. Communication privacy can also be provided using a link-layer encryption system, like TinySec [23, 28].  
**Authentication:** A secure scheme needs to be compatible with all types of public key cryptography (e.g., RSA, elliptic curve cryptography (ECC)), and depending on the network situation, different algorithms can be employed. In the TinyECC library [26, 29], elliptic curve cryptography shows better performance over RSA (Table 3).
###### Abstract  
Understanding the creep behaviours of rocks is essential for the long-term stability of underground excavations in mining engineering. Creep behaviours are more important when the mining depth is greater, which leads to the emergence of weak rock masses and high in situ stresses. In this study, the creep behaviours of argillaceous sandstone (AS) were systematically investigated. For the experimental investigation, creep tests were conducted on AS with different confining pressures (3, 6, 9, 12, 15, and 18 MPa) using an MTS815.02 rock mechanics test system. The mechanical characteristics of AS were analysed. For the numerical study, a nonlinear creep model of AS under equal and different confining pressures was established based on rock creep theory and plastic theory. The results showed that confining pressure could effectively improve the creep failure strength of AS, accelerating its creep deformation rate and process and reducing the final expansion volume. The nonlinear creep model was embedded in the FLAC3D software, and the experimental and numerical results agreed well. The experimental investigation and proposed creep model can provide important guidance in underground mines for safe long-term stability of underground excavations.  
Keywords:creep behaviour; argillaceous sandstone; confining pressures; nonlinear creep numerical model +
Footnote †: journal: Applied Sciences
## 1 Introduction
### The Viaduct Environment  
Some of the parameters that influence the wireless channel of the viaduct environment have been illustrated in Figure 1. Viaducts usually cover over 60% of the HST mileage [16]. Viaducts enable a connection of two points of terrain that appear to be of the same height. On the other hand, these can also be used to pass over water, a valley, or a road. Viaducts provide smooth rails to enhance the higher speed of the train. In the viaduct environment, the multipath components are associated with reflection or scattering from obstacles like tall buildings or trees. The relative height between the BS and the viaduct strongly impacts the received signal. The LOS component is dominating in this situation due to the viaduct's relatively high altitude to the surrounding topography. However, the distribution of the surrounding scatterers still impacts the received signal.  
Figure 1: The viaduct environment.
# Cognitive Interference Cancellation with Digital Channelizer for Satellite Communication
## 7 Conclusions  
In satellite communication, a digital channelizer can be adopted in a satellite to efficiently support multiple transponders. In this scenario, a digital channelizer based on a filter bank was used for cognitive interference cancellation with low complexity. This is done by detecting the subchannel with tone interference and omitting this subchannel in the frequency domain, i.e., after an analysis filter, the interference can simply get eliminated. Even though this simple approach is effective for cancelling tone interference, better interference detection performance was achieved by an improved method exploiting the properties of an FFT operation. By making two channelizer outputs with even- and odd-indexed inputs, we achieved an enhanced detection performance with the same number of subchannel blocks. With simulations and theoretical analysis, the performance of both the simple and improved approaches for interference detection were verified. It was also shown that the cancellation of interference with power less than that of the desired signal component in one subchannel is not needed. The proposed cognitive interference cancellation schemes exploit the inherent characteristics of the digital channelizer required for the flexible utilization of transponders. With the analytical and numerical results, the effectiveness of the proposed methods is verified and the design guideline of the cognitive interference cancellation based on the digital channelizer is provided.  
Conceptualization and methodology: B.K.; Formal analysis and writing-original draft: H.Y.; Validation and writing-review & editing: S.N. All authors have read and agreed to the published version of the manuscript. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (2019R1A2C1083988) and by the Institute for Information & Communications Technology Planning and Evaluation (IITP) grant funded by the Korean government (MSIT) (No. 2018-0-00190, Development of Core Technology for Satellite Payload). The authors declare no conflict of interest.
# Semi-Supervised Deep Subspace Embedding for Binary Classification of Sella Turcica
## 2 Materials and Methods
### Semi-Supervised Methods
#### 2.2.3 Contrastive Learning  
Contemporary studies have shown that contrastive learning (CL) is effective in extracting representations from unlabeled data. Its main advantage is its ability to learn invariant representations by comparing different views of input samples. The SimCLR [50] approach treats an augmented version of the original image as a positive sample, while views of other images in the same batch are considered negative samples. In contrast, BYOL [51] uses an augmented view of the image and trains an online network to predict the representation generated by a target network for the same image under various augmentations. The target network is updated using a moving average of the online network's parameters. SimSiam achieves notable performance through self-supervised learning alone, stopping gradient operations without requiring negative sample pairs, large batch sizes, or momentum encoders [52]. An alternative method involves clustering [53]. The SwAV model introduces K prototype variables, with each prototype representing a shared feature of a sample type, enabling the more reliable clustering of samples within a batch. The model then utilizes contrastive learning based on the clustering outcomes to enhance sample representation.  
While contrastive learning and other semi-supervised methods show significant promise, a dearth of research addresses the concurrent use of coarsely labeled and unlabeled data in medical imaging. One exception is a study on histological image classification [54], where the feature network is pre-trained using self-supervised learning to extract information from all training instances, followed by supervised learning with a margin-based loss function in a deep attention-based MIL network [55]. However, to our knowledge, SSLDSE learning has not been applied to the binary classification of ST. This approach, which combines a limited amount of coarsely labeled data with a larger set of unlabeled data, offers significant potential for reducing the annotation burden. The proposed SSLDSE framework underwent performance comparison against state-of-the-art models, including AL, GAN, CL, and a modified Inception-ResNet-v2, using accuracy, precision, recall, F1 score, blind test results, and ROC curve values for ST classification. This analysis aims to understand the framework's effectiveness in tackling the challenges of classifying ST morphological structures while reducing the reliance on large labeled datasets.