esa-sceva/satcom-chunk-collection huggingface dataset:
## 1 Introduction
### Related Work
#### 1.3.4 Integrating IVR and Serious Games for Physics Learning  
The integration of IVR and serious games has emerged as a promising approach in STEM education, providing highly interactive and immersive experiences that enhance conceptual understanding [38]. Several studies have explored the synergistic effects of IVR and gamified learning [39], demonstrating that these technologies can significantly improve students' ability to grasp motion-related physics concepts [40].  
Unlike traditional physics simulations, IVR-based serious games offer real-time experimentation, where students can manipulate launch angles, velocities, and trajectories in an interactive setting. This combination fosters higher-order thinking skills, allowing students to formulate hypotheses, test them in a controlled environment, and refine their understanding based on observed outcomes. Research by [6; 41] highlights that students who use IVR-based serious games for physics learning show not only improved test scores but also greater confidence in applying concepts to real-world scenarios.  
Despite these advantages, evaluating the effectiveness of IVR-based serious games remains an ongoing challenge. Comparative studies and case analyses, such as those outlined in [42], have underscored both the benefits and challenges of integrating these technologies into classrooms. The need for continuous evaluation and evidence-based adjustments is fundamental to optimizing serious game applications in IVR. This includes adaptations based on user feedback and empirical studies, ensuring that these tools evolve to meet educational demands effectively [6].  
While IVR and serious games have shown independent success in enhancing physics learning, the full potential of combining both methodologies has yet to be fully explored. Our study contributes to this emerging field by introducing \"Parabolic Basketball VR\", a game specifically designed to teach projectile motion through a gamified IVR experience. Unlike prior IVR-based physics applications, this game incorporates real-time trajectory visualization, interactive control over variables, and gamified challenges, making it a unique tool for learning kinematics in an engaging and scientifically rigorous manner.
## 3 Architecture
### Hardware  
The main hardware devices used in the proposed solution are the drone, and the AR device used as a user-interface, both of which are briefly described below. Additional hardware, such as the smartphone connected to the drone's remote and the computer server hosting the message broker, are generic and need no further elaboration.  
Developing and testing the architecture was performed using DJI's Mavic 2 Enterprise Dual and Mavic Mini drones. The DJI Mobile SDK platform offers high-level control of the aircraft and the camera-gimbal system, low latency video feed retrieval from the camera, and state information about the aircraft and the controller through various sensors, all of which are essential for development. For outdoor testing, we primarily used the larger Mavic 2 Enterprise Dual drone with its onboard obstacle avoidance system, which was important for safety reasons when implementing gesture control. For indoor testing, the smaller and lighter Mavic Mini was used.  
Microsoft's HoloLens 2 was used as an augmented reality platform. HoloLens is a head-mounted system that can display virtual objects in the real world, with the use of two see-through holographic displays. It has a plethora of onboard sensors to understand its surrounding environment (spatial mapping) including four RGB cameras, which combined with a Time-of-Flight Depth sensor, are used to track the user's hands. In addition, two infrared cameras are tracking the user's eyes, optimizing object rendering, and a microphone array can be used to issue voice commands. We capture hand tracking data through the HoloLens interface and translate them into UAV commands to control the drone and the camera. We also use the head tracking information the HoloLens provides to rotate the drone in accordance to head movement. HoloLens was selected because it provides three features necessary for the presented application: AR visualization, hand tracking, and autonomous operation (i.e., not tethered to a computer).  
Figure 1: System architecture and data flow between components.
## 5 Simulation Results
### Filter-Length Analysis  
The last stage of our simulations was filter-length analysis, where we defined the filter length that is suitable for the RadCom application. We mainly fixed the SNR to 10 dB and performed both detection and communication to observe how filter length can either improve or worsen the performance of the UFMC RadCom system.  
The frequency selectivity of the filter is is what makes UFMC signal well-localized in the frequency domain and reduces OOB emissions. However, filter-frequency selectivity may cause system performance loss, as Figure 10 shows. When filter length increases, selectivity among subcarriers increases. On the basis of these results, we recommend that filter length should be chosen to be proportional to the number of subcarriers divided by sub-band size \(\frac{N_{c}}{Q}\).  
\[L\propto\frac{N_{c}}{Q} \tag{26}\]Figure 8: Uncoded bit error rate (BER) of UFMC vs OFDM under tapped delay line A (TDL-A) channel and maximal Doppler Shift: (**a**) maximal Doppler shift \(f_{d}=10\) Hz; (**b**) maximal Doppler Shift \(f_{d}=100\) Hz.  
Figure 10: UFMC with fixed sub-band size \(Q\) and different filter length \(L\): (**a**) \(Q=128\) and \(L=16\). (**b**) \(Q=128\) and \(L=70\).  
Figure 9: Uncoded BER of UFMC-CDMA under TDL-A channel and maximal Doppler shift \(f_{d}=100\) Hz.  
Figure 10 also shows that UFMC-CDMA, even with a high-scrambled signature sequence, suffered from the same deterioration as that caused by filter-frequency selectivity.  
Regarding the communication aspect of the RadCom UFMC system, we evaluated filter length only over an AWGN channel and with different sub-band sizes for a better comparison.  
The BER versus filter-length curves for different sub-band sizes are presented in Figure 11. By increasing sub-band size and filter length, overall performance was degraded. For the case of \(Q=16\), the BER was at \(10^{-3}\) dB for a filter length that ranged from 2 to 128. However, for \(Q=128\), the BER began to rapidly degrade as soon as the filter length reached \(L=16\). For other sub-band cases, degradation was close to \(L=\frac{N_{c}}{Q}\). Hence, optimal filter-length configuration \(L\) should be chosen to be smaller than \(\frac{N_{c}}{Q}\) for optimal performance.
## 3 Monitoring Results and Analysis
### Internal Forces in Steel Arches  
Figures 19 and 20 present the dynamic evolution of the internal forces in steel arches (including the axial forces and the absolute values of the bending moments) at different locations in the K89+729 section during construction. As shown in the figures, after the completion of steel arches, the steel arches immediately began to bear loadings and the internal forces at each location in steel arches kept increasing rapidly. Till the completion of primary linings, the axial forces and the bending moments in steel arches took up almost 50% of the final values. After the construction of the primary linings, the axial forces and bending moments in steel arches continuously increased, however the growth rate significantly slowed down. Till the completion of the second linings, the increments of the internal forces in steel arches accounted for about 40% of the final stable values in this period. After that, the internal forces in steel arches increased slightly and then reached the steady state eventually.  
Figure 21 demonstrates the final distribution of the internal forces in steel arches at two typical sections respectively corresponding to class IV and V surrounding rocks (layouts of the steel strain gauges are shown in Figure 6). The figure shows that the axial forces are compressive along the full length of the steel arches. The axial forces in steel arches at the tunnel vault are obviously smaller than that at the side wall, while the absolute values of the bending moments reach the maximum both at the vault and the side wall of the tunnel, which indicates that the steel arch vault is the most unfavorable position to bear loadings. In addition, the axial forces and bending moments in steel arches are relatively larger in the monitoring section with lower class of surrounding rocks.  
Figure 17: Time history plots of the axial forces in rock bolts at location C in the K89+729 section.  
Figure 18: Final distribution of the axial forces in rock bolts in different sections respectively corresponding to class III, IV and V surrounding rocks. The values in the figure are the axial forces in rock bolts in class V surrounding rocks.
## 6 PLGA Nanoparticles Functionalization
### Pretranscytosis Circulation  
#### 6.1.1 Size Modification  
Size modification is a crucial point for approaches intended to enhance pretranscytosis circulation of NPs for drug delivery, that is, NP stabilization in the blood circulation and escaping the reticuloendothelial system. In fact, NPs with mean diameters of 100 nm or less are excreted faster, whereas NPs with mean diameters over 200 nm may be sequestrated by the liver or spleen and thus exhibit a more rapid rate of clearance due to a more efficient uptake by phagocytes [111]. Moreover, NPs under 200 nm are compatible with systemic administration, and might be able to get through the BBB without much difficulty [112]. Therefore, NPs with diameters in this range (100-200 nm) would be optimal for in vivo applications [113].  
The control of the PLGA NP size during synthesis can be carried out by modifying surfactant or polymer concentrations, molecular weight of the polymer, solvent type, and/or phase ratio. The most frequently used surfactants include polysorbates (e.g., Tween 20, Tween 80) and poloxamers (e.g., Pluronic F127, Pluronic F68), poly(vinyl alcohols) (PVA, e.g., Mowiol X-88 and X-98) [114; 115]. Different organic solvents such as ethyl acetate, propylene carbonate, acetone and dichloromethane [116] allow production of smaller PLGA NPs.  
Consequently, careful tuning of these features has enabled significant advances in designing novel formulations for improved drug encapsulation parameters [117], particle stability, pharmacokinetics and release profiles [118].
# Autonomous Driving Assistance with Dynamic Objects Using Traffic Surveillance Cameras
## 5 Discussion  
Camera calibration using a reference checkerboard is a general approach used to estimate intrinsic parameters. It is a good method to extract the parameters. However, this approach is impractical in applications to traffic surveillance cameras in the real world because it requires a reference checkerboard to cover the entire monitored area. It is rarely possible to stop and restrict traffic for a camera calibration process where surveillance cameras are installed. In the field of traffic surveillance camera calibration, there is a vanishing point-based method that is available with man-made structures such as a lane, a road, a building, etc. The parameter of the lens distortion is required to estimate object positions. The vanishing point-based method sometimes assumes that an error from the lens distortion is ignored. The positions of multiple cameras are essential for fusion applications such as the object detection of vehicles and walkers in the system of urban surveillance cameras. To overcome the above issues, we proposed a camera calibration method suitable for traffic surveillance cameras. We assumed that the ground plane is the same height, and then we used only geometric information of the road where the traffic surveillance camera was installed because the HD map provides accurate geometric information. Compared with other methods, the proposed method has the advantage that the intrinsic and extrinsic parameters are directly derived without any other information. We demonstrated the performance of our method by conducting real data experiments. These experiments showed that the proposed method could successfully estimate camera parameters of the pan-tilt traffic surveillance cameras using HD map information as the reference points.
# Driving Safety Improved with Control of Magnetorheological Dampers in Vehicle Suspension
## 1 Introduction
### Vehicle Suspension  
The parameters of the passive suspension can be optimized in terms of driving safety, but it is associated with a reduction in driving comfort. This statement was confirmed in [5] with respect to different cases that indicate that suspension settings for spring and damper parameters corresponding to ride comfort or driving safety are contradictory. Parameters of commonly used passive suspension are hard to change after being manufactured and they are dedicated to certain vehicle destination, e.g., road and off-road vehicles or sports cars. However, still, varying road conditions require the suspension parameters to be constantly adapted.  
Active suspension systems are equipped with force generators that can effectively improve ride comfort and driving safety, as presented in [9], where the control methods for slow-active suspension were described. However, the high energy consumption of active suspension elements is their key disadvantage and is still an urgent problem described in the literature. The same authors presented, in [10], a study on energy consumption of an active suspension and proposed a weighted multitone optimal controller in order to minimise this consumption while the application of the ideal energy harvester was also analysed.  
The application of a less energy-consuming semi-active suspension is a competitive offer. The operation of semi-active suspension dampers, especially magnetorheological dampers, is based on control of dissipation of vibration energy. They can also offer a short time response studied in [11], which is critical in vibration control applications. The authors presented an experimental analysis of the MR damper response time and showed that, in most cases, the response time to step current excitation does not exceed 20 milliseconds. It is worth noting that, similarly to active solutions, semi-active dampers are also supported by an energy harvester, which further improves the performance of semi-active approach. For instance, a novel design of the MR damper was presented in [12], where a controllable damping mechanism was integrated with a converter of mechanical energy to electrical energy.  
Force-velocity characteristics of MR damper are strongly nonlinear, and they include hysteresis loops and force saturation regions [13]. Numerous models of MR damper were presented in the literature, including the Bingham model based on Coulomb force and viscous damping components [13]. A key element of the Spencer-Dyke model presented in [14] is a Bouc-Wen hysteresis component that was described by a nonlinear differential equation. The advantage of the MR damper model, which is based on hyperbolic tangent function, as presented in [15], is its simple form and good fit to the force-velocity experimental characteristics of MR damper. Furthermore, this model can be easily inverted, which is favorable in the case of control applications.
###### Abstract  
The use of Visible Light Communications (VLC) in vehicular applications has become a major research area due to its simplicity, high performance to cost ratio, and great deployment potential. In this context, this article provides one of the very few analyses and experimental evaluations concerning the integration of a light dimming function in vehicular VLC systems. For this purpose, a vehicle-to-vehicle VLC prototype has been implemented and used to evaluate the systems' communication performances in light dimming conditions, while decreasing the duty cycle from 40% to 1%, and increasing the communication range from 1 to 40-50 m. The experimental results showed that in normal lighting conditions, the VLC technology can easily support low duty cycle light dimming for ranges up to 40 m, while maintaining a \(10^{-6}\) BER. Nevertheless, in strong optical noise conditions, when the system reaches its SNR limit, the communication range can decrease by half, whereas the BER can increase by 2-4 orders of magnitude. This article provides consistent evidence concerning the high potential of the VLC technology to support inter-vehicle communication links, even in light dimming conditions.  
inter-vehicle communications; light dimming; \"lights-off\" visible light communications; optical communications; vehicle-to-vehicle communications; vehicular communications; visible light communication +
Footnote †: journal: Sensors
# A Novel Fragmented Approach for Securing Medical Health Records in Multimodal Medical Images
## 3 Materials and Methods
### Least Significant Bit (LSB) Steganography  
In computers, an image is defined as a group of gathered numerical values that create many light intensities in different regions of that image. These numerical values in bits represent a form of individual points, which are called pixels. In steganography, techniques and algorithms can be classified into two main categories: the first category is the image domain, while the second is the transformation domain. In the image domain, which is also known as a special domain, people use techniques to directly encrypt messages in each pixel intensity before the transformation is complete. In the transform (frequency) domain, people use techniques by transforming the images first and then encrypting the message inside the transformed images [10]. However, manipulation is necessary in these two methods, especially when spatial techniques are utilized. Also, there are many useful methods within the spatial domain technique itself. For example, the least significant bits (LSB) substitution technique, Exploiting Modification Direction (EMD), and Pixel Value Differencing (PVD). In addition, DWT, FFT, and DCT techniques are the most well-known methods in the transform domain.  
In this research, we utilized the LSB substitution technique, which is one of the most important techniques applied in steganography in the image domain. Overall, the objective of this technique is to generate an embedded image that is the original one since a minor part of the pixel values will be slightly changed. Therefore, neither machine learning nor bare eyes can identify or detect the change in that embedded image color and its original one [14]. Image steganography consists of two phases: the embedding and extracting phases. Figure 3 shows a basic block diagram of the embedding phase and extracting phase of LSB-based steganography.  
As stated earlier, hiding private information inside different types of digital images is known as the LSB steganography method. The idea of image steganography is very simple and basic. Digital images consist of pixels, and each pixel shows a certain color intensity of that particular region of the original image. In a black-and-white grayscale picture, the pixel's amount of gray color ranges between 0 and 255 shades. Zero represents a black, and 255 represents a white color. The idea of the LSB data encrypting method is used for the least significant bit of each pixel. The main goal behind LSB planting is that if we replace the last pixel's value, no visible change should appear in the original picture. For example, a grayscale image has 256 shades of gray color. If 0 is black and we change it into 1, then it means the pixel is still black, but we make it a little bit lighter, i.e., the shade has been changed, not the color, making it almost impossible to be detected.  
Figure 3: Basic block diagram of the embedding phase and extracting phase of LSB-based steganography.
###### Abstract  
Earth system models (ESMs) are a common tool for estimating local and global greenhouse gas emissions under current and projected future conditions. Efforts are underway to expand the representation of wetlands in the Energy Exascale Earth System Model (E3 SM) Land Model (ELM) by resolving the simultaneous contributions to greenhouse gas fluxes from multiple, different, sub-grid-scale patch-types, representing different eco-hydrorological patches within a wetland. However, for this effort to be effective, it should be coupled with the detection and mapping of within-wetland eco-hydroological patches in real-world wetlands, providing models with corresponding information about vegetation cover. In this short communication, we describe the application of a recently developed NDVI-based method for within-wetland vegetation classification on a coastal wetland in Louisiana and the use of the resulting yearly vegetation cover as input for ELM simulations. Processed Harmonized Landsat and Sentinel-2 (HLS) datasets were used to drive the sub-grid composition of simulated wetland vegetation each year, thus tracking the spatial heterogeneity of wetlands at sufficient spatial and temporal resolutions and providing necessary input for improving the estimation of methane emissions from wetlands. Our results show that including NDVI-based classification in an ELM reduced the uncertainty in predicted methane flux by decreasing the model's RMSE when compared to Eddy Covariance measurements, while a minimal bias was introduced due to the resampling technique involved in processing HLS data. Our study shows promising results in integrating the remote sensing-based classification of within-wetland vegetation cover into earth system models, while improving their performances toward more accurate predictions of important greenhouse gas emissions.  
HLS data; vegetation classification; wetland; methane; land surface models +
Footnote †: journal: Remote Sensing