esa-sceva/satcom-chunk-collection huggingface dataset:
# New Insights on Mechanical Stimulation of Mesenchymal Stem Cells for Cartilage Regeneration
## 4 Practical Applications
### Influence of Cell Distribution  
[PERSON] et al. [38] simulated the multiaxial mechanical loads that characterize the articular joint and observed the results derived from applying these forces on fibrin-poly(ester-urethane) scaffolds seeded with MSCs. The constructs were divided into three groups, represented in Figure 3: in the first group, the cells were evenly dispersed throughout the scaffold (Uniform); in the second group, the cells were asymmetrically disseminated within the matrix, forming a thin layer on the surface (Asymmetric); and in the third group, the cells were allowed to adhere only to the upper face of the scaffold (Surface Only). These different distributions were investigated in terms of matrix deposition in response to mechanical stress. The protocol employed 20 cycles of 10% compression, achieved by the raising and lowering of a ball onto the scaffold. The rotation on the ball generated shear friction of \(\pm 25^{\circ}\) at 1 Hz. Histological and immunohistochemical analysis showed that there was an increase in glycosaminoglycans and type II collagen levels in the Asymmetric group in comparison to the other two groups. Besides this, the cells in the Surface Only group produced a small amount of matrix, suggesting a hypertrophic-like phenotype. In conclusion, the pattern of cell distribution within the scaffold is a critical parameter to take into consideration, and matrix deposition could be enhanced by considering the anisotropic properties of the materials.  
Cell distribution can also be controlled by physiological mobilization of the cells, from their niches to different areas of the scaffold, employing biomechanical stimulation. Long-lasting regeneration of articular cartilage after surgical techniques like autologous chondrocyte implantation (ACI), mosaicplasty, and microfracture can be hampered by failure to attract progenitor cells, leading to the formation of fibrocartilage. In vitro loading compression provided by a bioreactor, such as 10% strain at 0.3 Hz frequency, applied intermittently for 24 hours, was shown to induce the mobilization of MSCs from a reservoir to an alginate scaffold located above it [39]. This experiment aimed to provide a model of a cartilage defect in the tibial plateau in order to evaluate the possible effect of biomechanical loading on cell recruitment from the subchondral bone. The mobilization of the stem cells from the reservoir required the supporting effect of laminin-521 (LN-521), as it is a basement membrane protein which exerts a pivotal role in cell adhesion and migration mechanisms. The processes involved in antigravity migration within the scaffold are still the object of study and could imply extracellular signals between the cells and also physical fluidic movements induced by the stimulation of the bioreactor.
## 2 Material and Methods
### Kinetic Tests  
To estimate the rate of Cu(II) and phosphate sorption on FHO-A, the batch kinetic tests were conducted. First, FHO-A (500 mL) was prepared and then a sorption test was initiated by individually adding Cu(II) and phosphate to give the following initial concentrations: Fe = 2.0 mM, Cu(II) = 10 mg/L, and phosphate = 15 mg/L. Each sample was taken out at 5, 10, 30, 60, 180, and 360 min. The initial pH was adjusted to 5.0 and the pH was measured but not adjusted during the experiment.  
Pseudo 1 st and 2 nd order models were used to describe the initial state of adsorption and anticipate the adsorption behavior through the whole range, respectively [21]. Each parameter was calculated by fitting with the experimental data.
# Capacity Bounds for Dense Massive MIMO in a Line-of-Sight Propagation Environment
## Appendix A Derivation of \(\|\mathbf{g}_{k}\|^{2}=M\beta_{k}\)  
From Equation (1), we can write each element \(g_{k,m}\) of \(\mathbf{g}_{k}\) as  
\[g_{k,m}=\sqrt{\beta_{k}}e^{i\phi_{k}}e^{-j(m-1)\sin(\theta_{k})}. \tag{1}\]  
Therefore, using the very definition of the product of two matrices [39], we have  
\[\begin{split}\|\mathbf{g}_{k}\|^{2}&=\sum_{m=1}^{M} \left|\sqrt{\beta_{k}}e^{j\phi_{k}}e^{-j(m-1)\sin(\theta_{k})}\right|^{2}\\ &=\sum_{m=1}^{M}\left|\sqrt{\beta_{k}}\right|^{2}\left|e^{j\phi _{k}}\right|^{2}\left|e^{-j(m-1)\sin(\theta_{k})}\right|^{2},\end{split} \tag{2}\]  
where \(\left|e^{i\phi_{k}}\right|^{2}=\left|e^{-j(m-1)\sin(\theta_{k})}\right|^{2}=1\) and \(\left|\sqrt{\beta_{k}}\right|^{2}=\beta_{k}\), therefore  
\[\|\mathbf{g}_{k}\|^{2}=\sum_{m=1}^{M}\beta_{k}=M\beta_{k}. \tag{3}\]
# A Large Capacity Histogram-Based Watermarking Algorithm for Three Consecutive Bins
## 1 Introduction
All of them are based on this strategy, which partitions every three consecutive bins into a group for embedding a one-bit watermark, which guarantees that if a larger bin size is chosen, the image quality of the smooth area will not decrease obviously. Meanwhile, the authors of [15] have proposed to use a predefined threshold to select a large population of pixels in the hope that this will suffice to eliminate possible bad bins. Besides, [PERSON] et al. [17] proposed a histogram-shape-related index method to form and select the most suitable pixel groups for embedding. With their method, some possible bad bins can also be eliminated to some degree. Recently, other possible drawbacks, such as the lower embedding capacity existing in [PERSON] et al. 's method [13], were also resolved by [PERSON] et al. [18]. Although these improved schemes [14; 15; 16; 17; 18] are effective to some extent, they pay no attention to a drawback existing in the original embedding procedure. That is, the embedding procedure of [13] failed to take the approximately equal number of adjacent histogram bins into account, and thus resulted in a direct decline of embedding capacity. Obviously, this restricts many applications, especially limited to those with a strict requirement for watermark capacity. In this paper, we propose a large capacity histogram-based watermarking algorithm for three consecutive bins. To the best of our knowledge, this is the first scheme to expand from two bins to three bins. The improvement that we propose for watermark embedding differs from those proposed by recent state-of-the-art publications. This is because the proposed watermark embedding algorithm can remedy the drawback in the original design well, but other improved works remain almost invariant in the watermark embedding algorithm. A predefined threshold, together with a block-based pixel modification and new watermark embedding procedures, also makes the proposed scheme a viable alternative to the histogram-based methods. Experiments demonstrate that the maximum embedding capacity of using the proposed histogram-based watermarking algorithm outperforms all the existing histogram shape-based publications and can truly achieve one bit per bin (bpb). Meanwhile, the image quality of the stego-image, which is generated by modifying a part of the pixel values of the original image to carry the watermark information, together with the capability to resist some geometric attacks, can also be ensured. The rest of this paper is organized as follows. Section 2 describes the invariance of the histogram shape and existing histogram-based watermark embedding. Detailed embedding and extraction processes of the proposed scheme are described in Section 3. Experimental results and related analyses are given in Section 4, followed by a conclusion in Section 5.
## 3 Challenges for a Future Imaging Radar for Space Observation  
### Future Situation in Earth Orbit  
The use of near-Earth space has grown drastically since the first artificial satellite Sputnik was launched in 1957. Sixty years later, the annual number of launched objects is raising exponentially (see Figure 13). As of 2024, more than 19,000 satellites have been placed into Earth orbit [19]. In addition, there is a constantly increasing amount of space debris. It is estimated that around 4500 objects orbiting Earth are larger than 10 cm, around 1,100,000 objects between 1 cm and 10 cm, and around 130 million objects between 1 mm and 1 cm, as of August 2024 [19]. The amount of space debris is constantly rising due to debris breaking apart, explosions of spent rocket stages and collisions of debris between each other or from debris with satellites. When two space objects collide, thousands of new pieces of debris can be created. This is what happened, for instance in 2009, when the defunct Russian military satellite Cosmos-2251 collided with the communications satellite Iridium-33. Many thousands of new pieces of space debris were detected. This large amount of space debris around Earth is a significant threat to all active satellites as any collision can damage or completely destroy a satellite generating even more debris.  
In recent years, so-called mega constellations have also been launched. In each of these constellations, thousands of small satellites are placed into orbit. The growing object density increases the overall collision probability, as any of these satellites can collide with each other or with space debris, creating a new cloud of debris.  
Finally, every active satellite becomes space debris at the end of its life if not actively de-orbited, or even earlier in the event of a failure. In this case the defunct satellite stays as debris until it re-enters in the Earth's atmosphere after spending many years in orbit or until the satellite is taken out of orbit using special de-orbiting missions [7].  
Figure 12: Photo of an Atlas-5 Centaur rocket body [18].
## 6 Discussion
### Issues for Practical Use  
An important method for improving accuracy is to reduce the observation error when attaching and detaching each time. In this study, the earphones were left on for 30 trials in Session 1, whereas in Session 2, they were removed and attached after each trial. Therefore, we compared the EER and AUC of Sessions 1 and 2 to examine the effects of attaching and detaching the earphones. The EER and AUC of Sessions 1 and 2 are shown in Figure 12. Comparing Sessions 1 and 2, the authentication accuracy was higher in Session 1, where 30 measurements were taken while wearing the earphones. This difference in accuracy is due to observation errors during attachment and detachment. The EER for bilateral ear acoustic authentication (Joint method) in Session 1 was 0.026%, which was 0.36% lower than that in Session 2. If the error due to each attachment and detachment can be reduced, EER = 0.026% can be used for authentication. Therefore, it is essential to devise earpieces and earphone shapes that can reduce the errors caused by each attachment and detachment.
# Review of Substrate Integrated Waveguide Circuits for Beam-Forming Networks Working in X-Band
###### Abstract  
A review of substrate integrated waveguide (SIW) components designed for the use in beam-forming networks working in X-Band is presented. The proposed devices are four-port and six-port couplers and magic tees for the network. The devices take full advantage of the use of SIW technology in order to reduce size, weight, and cost. The design processes of all devices are exposed, and the experimental results of prototypes show the feasibility of these solutions.  
Keywords:substrate integrated waveguides; directional couplers; antennas +
Footnote †: journal: Applied sciences
## 8 Conclusions  
To date, all wireless systems have assumed that the radio propagation channel is fixed by nature and cannot be changed. It is only well accounted by increasingly complicated transmission/reception systems. Moving away from this hypothesis could be a significant evolutionary leap for 5G networks and beyond. The innovative idea of developing wireless networks is managed and controlled through RIS-assisted wireless communications.  
In this work, we reviewed state-of-the-art research findings in the emerging field of RIS, given its potential for substantial performance improvement by adapting the propagation environment for next-generation wireless communication networks. Further, an in-depth overview of RIS is provided for wireless communications regarding its principle, opportunities, and challenges encountered for metasurfaces and reflect arrays RIS. Further, extensive survey on various candidate implementations such as phase shift and LCs based RIS has been reviewed. We have demonstrated the key differences that distinguish RISs as a modern technology compared to conventional literature technologies. In addition, RIS optimization methods using existing and novel beamforming techniques are discussed. Furthermore, comprehensive summaries are given for practical considerations of RIS hardware design and optimization.  
Additionally, a detailed review of existing FPGA-based dynamically controlled RIS structures, and the future opportunities associated with this new technology has been presented. The possible use cases where the RIS could play an important role in various application areas, such as UAV, mmWave, FSO, and VLC communications, have been demonstrated with future challenges. Finally, the fundamental research issues to be addressed have been explored to full determine the potential of these technologies.  
[PERSON] and A.C., designed the research. [PERSON] conducted the investigation and literature review, [PERSON] writing--original draft preparation. [PERSON], [PERSON] and [PERSON] writing--original draft preparation. MITACS and Thales-Quebec provided the research funding to the first author at University of Quebec in Chicoutimi (UQAC), Canada. [PERSON] was the corresponding author. All authors have read and agreed to the published version of the manuscript.  
This research was funded by MITACS and Thales-Quebec, grant number UBR 326853.  
Not applicable.  
The data that support the findings of this study are available from the corresponding author [PERSON], upon reasonable request.  
The authors thanks to the anonymous reviewer and editors for their constructive comments.  
The authors declare no conflict of interests.
## 6 Conclusions
### Future Work  
As directions for future work, the following research initiatives will be taken into consideration:  
* Implementing multi-label classification to enhance the realism of the analysis. This approach will allow a single comment containing both aggressive and bullying content to be classified under both categories simultaneously, offering a more comprehensive representation of the data.
* Expanding the scope of this study to include multilingual and culturally diverse datasets. While this study focused exclusively on English language data, future research will incorporate languages such as Bengali, Hindi, Urdu, and Norwegian for multi-class classification of multi-modal data to make the model more robust and applicable globally.
* Integrating additional data types, including stickers, voice messages, videos, and GIFs, into the existing dataset. This will enable the classification system to handle diverse content types commonly found in social media comment sections, thereby improving its robustness and applicability.
* In this work, we focused only on the model's performance and technical implementation. However, we recognize the importance of addressing how non-technical stakeholders can understand and trust the model's decisions. So, in future work, we will explore approaches to interpretability, such as explainable AI techniques (e.g., SHAP or LIME) and visualizations tailored for non-technical users.
* Exploring advanced models such as Swin (Shifted Window) transformers, multi-scale vision transformers, and BLIP-V2 (Bootstrapping Language Image Pre-training Version 2) to further enhance classification performance.  
I.T.; Supervision, V.N.; Project administration, I.T. and V.N. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. Not applicable. Not applicable. Data Availability Statement: The data presented in this study are available on request from the corresponding authors. This work is the result of a 60-ECTS master's thesis at the Department of Science and Industry Systems, Faculty of Technology, Natural Sciences and Maritime Sciences, University of South-Eastern Norway, Kongsberg, Norway. The authors declare no conflicts of interest. The following abbreviations are used in this manuscript: SM Social Media DL Deep Learning CNN Convolutional Neural Network LSTM Long Short-Time Memory GRU Gated Recurrent Unit RoBERTa Robusly Optimized BERT Pre-training Approach ViT Vision Transformer ResNet Residual Network BERT Bidirectional Encoder Representations from Transformers DistilBERT Distilled BERT TP True Positive TN True Negative FP False Positive FN False Negative OCR Optical Character Recognition GUI Graphical User Interface HTML HyperText Markup Language CSS Cascading Style Sheets
## 4 User Testing Methodology
### Test Design  
A structured test design was employed to evaluate the VA's capabilities effectively. This design focused on three primary aspects: the number of queries, scoring criteria, and critical performance metrics. This approach enabled a detailed analysis of the VA's performance across various dimensions.  
The total number of queries submitted during the user testing process was 561, which resulted from each of the 187 participants being asked to submit three independent queries. This approach provided a substantial data set for analyzing the VA's response consistency and accuracy across different inquiries. The design of each query was intended to reflect common questions that might be posed by students or staff in a university setting, encompassing a range of topics from academic policies to administrative procedures.  
The VA's responses were evaluated using a multi-faceted scoring system incorporating binary (Yes/No) and scale-based ratings (Table 1). The binary scoring was focused on the accuracy of the response, categorized as either accurate (Yes) or containing errors (No). Furthermore, the VA's responses were rated by participants on a Likert scale ranging from 1 to 5 across various dimensions, which included relevance, coherence, and overall quality. A rating of 1 was indicated as a highly unsatisfactory response, while a rating of 5 was signified as an excellent response that was fully aligned with user expectations. This nuanced scoring system provided insights into specific areas where the VA excelled or required improvement, enabling a comprehensive analysis of its strengths and weaknesses.  
The scoring system provided a well-rounded framework for assessing the VA's technical accuracy and overall user experience. This multifaceted approach enabled a more nuanced evaluation, which helped to pinpoint areas for further refinement while affirming the VA's effectiveness across diverse query types.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**No** & **Question** & **Grading Method** \\ \hline
1 & Has a hallucination been observed during prediction? & Binary answer yes or no \\
2 & Are all the information and data corrected? & Binary answer yes or no \\
3 & Evaluate the relevance of the answer to the question. & Rating from 1 to 5 \\
4 & Evaluate the grammatical and syntactic quality. & Rating from 1 to 5 \\
5 & Rate how the AI model understood the queries. & Rating from 1 to 5 \\
6 & Have you noticed any logical errors in your response? & Binary answer yes or no \\
7 & What is your overall impression of the responses? & Rating from 1 to 5 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Value range of user test scores.
# Displacement Analyses of Main Structure of Parallel Pit Excavation and Analysis of Countermeasures
## 3 Parallel Pit Excavation Scheme
### Discussion
#### 4.3.2 Relative Stiffness Coefficient of the Main Structure
Figure 19 shows the relationship between the maximum lateral deformation \(\delta_{hm}/H_{e}\) and the relative stiffness coefficient \(R_{d}\) according to the above four excavation cases, where the maximum lateral deformation \(\delta_{hm}\) is normalized to the excavation depth \(H_{e}\), in order to value the relative stiffness magnitude required for the structure through the maximum control deformation, and thus to carry out a more reasonable structural design. Fitting \(\delta_{hm}/H_{e}\) with \(R_{d}\), the optimal stiffness required for the main structure is calculated through the structural deformation values specified in the design code, which can provide a reference for the designer in the design of the supporting structs. The fitting formula is the following Equation (7):  
\[\delta_{hm}/H_{e}(\%)=0.011\times{R_{d}}^{0.51}\quad R^{2}=0.9824 \tag{7}\]  
The goodness of fit (\(R^{2}\)) is 0.9824. It shows that \(\delta_{hm}/H_{e}\) fits well with \(R_{d}\). It can be seen that \(\delta_{hm}/H_{e}\) and \(R_{d}\) are positively correlated, and the larger the relative stiffness coefficient \(R_{d}\) of the main structure, the larger the maximum lateral deformation \(\delta_{hm}\). \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Excavation Schemes**} & \multicolumn{4}{c}{**Relative Stiffness Coefficient**} \\ \cline{2-5}  & **Struct 1** & **Struct 2** & **Struct 3** & **Struct 4** \\ \hline Case 1 & 21 & 7 & 1 & 10 \\ Case 2 (03A finished) & 65 & 50 & 43 & 36 \\ Case 2 (02B finished) & 30 & 15 & 4 & 2 \\ Case 3 & 23 & 8 & 2 & 8 \\ Case 4 & 13 & 7 & 3 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Relative stiffness coefficient of the main structure. Combined with the steel pipe struct deformation provisions in the project design instructions, the maximum horizontal deformation of the steel pipe struc  
Figure 19: Influence of the relative stiffness coefficient on the main structure. Figure 20: Horizontal deformation curve of steel pipe struct above the middle 1 slab. With the excavation of the pit on both sides of the cover excavation area, the horizontal deformation of the steel pipe structs gradually increases, and the maximum horizontal deformation is 3.5 mm, and the deformation trend is more similar. The numerical simulation results are in good agreement with the monitoring data, which verifies the feasibility of Case 4.
# A Novel Methodology for Planning Urban Road Safety Interventions
## 4 Validation of the Proposed Methodology via Case Study Application
### Cost-Benefit Analysis of Safety Interventions in Parma  
A proactive CBA was conducted to evaluate proposed safety interventions for critical road segments in Parma. The analysis aims to quantify potential reductions in fatalities and serious injuries (FSI), as well as the associated decrease in societal costs, including healthcare expenses, legal fees, and productivity losses. Simultaneously, the financial feasibility of each intervention was assessed to ensure sustainable resource allocation.