esa-sceva/satcom-chunk-collection huggingface dataset:
# Biophotonics in Dentistry
## 3 Applications in Dentistry
### Photoelasticity
In this study, the technique was refined through the use of a circular polariscope and an image-processing system, which allowed an enhanced sensitivity and accuracy, not only allowing analysis of fringe patterns but also the ability to identify signs of fringe orders, thus improving understanding of the stress distributions. In 2004, the effect of the morphology of occlusal surfaces on transfer of loading on the tooth apex was investigated using photoelastic methods [94]. The study concluded that the surface morphology of occlusal surfaces is a highly significant factor influencing the magnitude and direction of stress. [PERSON] et al. (2004) investigated stress and strain magnitudes of different models of implants and observed the resultant isochromatic fringe patterns around the implants [95]. The study concluded butt-joint and internal-cone oral implants have similar distribution characteristics. Over the years, the use of photoelasticity to determine the biomechanics and stress distributions of various implant designs has allowed for optimisation of dental prostheses. The technique has also been used as a means of comparison between different dental biomaterials. In 2011, [PERSON] and [PERSON] completed a photoelastic stress analysis of different material composites of endodontic posts, including a stainless-steel post and a fibre-reinforced post with a silver amalgam or composite resin core [96]. Two-dimensional photoelastic models were utilised to stimulate root dentin, and each model was studied with two force magnitudes in two directions.
## 3 Issues in Implementing URLLC
### Energy Efficiency Concern for End-User Device  
Most of the wireless devices employ a sleep mode operation to save energy. The devices need to act immediately upon receiving a packet from a network to avoid any delay. Similarly, the devices periodically check awaiting packets on the network to avoid latency [21]. The current energy-saving states defined for user equipment (UE) are not suitable for URLLC-based service. However, the UE can lose battery drastically as a result of the high frequency of data checks over the network.
# An Integrated Optimization Method of High-Speed Railway Rescheduling Problem at the Network Level
## 4 NSGA-III Algorithm  
Train timetable and train set circulation plan adjustment at the railway network include three objectives. In the real world, the additional operation cost, total delay, and number of transfer passengers are in a constant balance process. If we just take two objectives into account, some better adjustment options will probably be missed, and the quality of the optimization scheme will be influenced, too.  
Therefore, in order to improve the quality and diversity of the optimization scheme as much as possible, we use the NSGA-III algorithm, which can take three or more objectives into account at the same time to solve the rescheduling problems. It uses non-dominated sorting to grade individuals in the population, maintains the diversity of the population through well-distributed reference points, and then selects the appropriate population for the next iteration.
## 2 Related Literature and Problem Statement
### Problem Statement  
From the discussions in Section 2.1, we can conclude the following:  
* Existing hybrid domain algorithms fail to maintain a proper balance among imperceptibility, robustness, security, and capacity simultaneously.
* Certain algorithms utilize visible images as watermarks, which are unsuitable for identifying authentic recipients.
* Can watermark image be easily applied to new content without any adjustment?
* Some methods lack the incorporation of security techniques for encrypting the watermark image.
* The majority of the methods overlook hybrid attacks and do not calculate the watermark embedding capacity.  
These findings highlight the need for developing improved hybrid domain algorithms that address these limitations and provide enhanced imperceptibility, robustness, security, and capacity performance.
# Design of Wideband Decoupling Antenna Array for 5G Smartphones at N77/N78/N79/WLAN 5 GHz Bands
## 3 Performance of the Eight-Element Antenna System
### Eight-Element MIMO Antenna System Prototype
#### 3.1.1 S-Parameters  
In Figure 13, we can see that the \(-10\) dB operating frequency of Ant 1 and Ant 2 is 3.30-5.83 GHz, and the bandwidth length is 2530 MHz, which completely covers the N77/N78/N79 bands as well as most of the WLAN 5 GHz bands. The worst isolation  
Figure 11: Effect of different W\({}_{\rm c}\) values on S-parameters.  
Figure 12: (**a**) Side borders of the prototype. (**b**) The interior of the prototype. (**c**) The back of the prototype.  
occurs between Ant 2 and Ant 3 at 3.55 GHz with \(-\)12.16 dB. Due to the connection of SMA connectors and unavoidable processing and measurement errors during modeling and measurement, the test results of the fabricated prototypes differ slightly from the simulation results, but the overall trend is consistent.
# A Dynamic-Routing Algorithm Based on a Virtual Quantum Key Distribution Network
## 2 Technical Foundation
### Design of QKP
#### 2.3.2 Design Steps  
Assuming a QKP of size \(M_{0}\), which needs to be enlarged or reduced to \(M_{1}\), the following design steps are shown.  
First, calculate the average utilization rate of the current QKP U. It is known that the generation rate of quantum keys is \(R_{\mathrm{ij}}\) and the consumption rate of quantum keys is \(Q_{ij}\). Then, the relationship between the three can be expressed by the following equation:  
\[U=\frac{Q_{ij}}{R_{ij}+M_{0}} \tag{3}\]  
The average usage of a QKP is equal to the ratio of the number of keys consumed from the QKP per unit of time to the sum of the number of new keys generated from the QKP per unit of time and the current QKP size. The size \(M_{1}\) of the target pool is then calculated, giving:  
\[M_{1}=\frac{M_{0}}{U} \tag{4}\]  
where \(U\) denotes the average number of times each QKP key is used. Therefore, the target key pool size needs to be set to the original key pool size divided by the average utilization to maintain a given average utilization. This ensures that the key pool can always meet the expected demand.  
Finally, if \(M_{1}>M_{0}\) current capacity, the pool size is increased, and if \(M_{1}<M_{0}\) current capacity, the pool size is reduced.  
Figure 3 shows a schematic diagram of the structure of the QKP, which consists of three parts, namely:  
1. Quantum key sending and receiving device: responsible for generating and sending quantum keys and receiving and measuring keys sent from other devices.
2. The key storage device: responsible for storing the distributed quantum keys for subsequent use.
3. Quantum encryption application: uses the generated and stored keys to encrypt and decrypt the information to be transmitted. In this system, the QKP is deployed inside two communication nodes, and both relaying and encryption processing are implemented through a key control server that increases or decreases the capacity of the QKP according to the amount of service demand.  
Since most QKD systems spend a significant amount of time resources generating and storing quantum keys but only use them for a specific period, accumulating too many keys at other time nodes wastes limited resources [37]. By dynamically scaling up or down the capacity of a QKP, the system can more quickly change its power and respond to changing workload demands as needed. A fixed number of QKD systems may not ideally balance the relationship between key generation security and resource consumption. Scaling down the capacity of the QKP as required ensures a high level of security with minimal resources.  
Figure 3: QKD network architecture.
# RD-SLAM: Real-Time Dense SLAM Using Gaussian Splatting
## 2 Related Work
### 3 DGS-Based SLAM  
Compared with the NeRF-based SLAM method, 3 DGS-based SLAM combines the advantages of explicit and implicit representations. SplaTAM [19] simplifies 3 DGS by removing view-dependent appearance and using isotropic Gaussians. The system uses silhouette-guided differentiable rendering for incremental 3D map construction. GS-SLAM [20] designs a coarse-to-fine tracking technique during pose estimation, selecting reliable 3D Gaussians to optimize the camera pose. An adaptive extension strategy is also proposed to add new or remove noisy 3D Gaussians effectively. Gaussian-SLAM [21] outlines the limitations of 3 DGS and proposes an online learning method for 3D Gaussian that achieves good rendering quality on both real-world and synthetic datasets. MonoGS [22] derives the analytic Jacobian of camera pose with respect to a 3D Gaussian map, allowing the pose to be optimized together with scene geometry. The system operates at 3 FPS and achieves high-quality tracking and map construction at monocular or RGB-D inputs. However, existing methods rely exclusively on 3D Gaussian for tracking and mapping, which requires a significant amount of time to perform multiple iterations of optimization, making it impossible to run the system in real-time.
## 2 Materials and Methods
### Proposed Methods
#### 2.2.1 Data Pre-Processing  
This dataset consists of 239 images, which include 36 images with no findings, 154 images with osteopenia, and 49 images with osteoporosis. To address the issue of an imbalanced sample distribution in the dataset, we employed the synthetic minority oversampling technique (SMOTE) [22]. SMOTE involves analyzing the minority samples, artificially generating additional samples based on them, and adding them to the dataset. This technique helps to prevent the model from becoming overly specialized and lacking generalizability. After applying SMOTE, the dataset was expanded to include 154 images with no findings, 154 images with osteopenia, and 154 images with osteoporosis [23]. The regions of interest (ROIs) in this study were the patella, femoral condyle, and tibia regions of the patient's legs. The patella is a triangular bone structure located at front of the thigh, in front of the knee, and is attached to the condyle of the femur. The condyle of the femur are two enlarged parts of the lower end of the femur that connect with the tibia to form the knee joint. The tibia is a long bone in the front of the lower leg, just below the knee. Since the data provider has already manually segmented these areas, we can directly utilize these images for further processing.  
To normalize the images, they were converted to grayscale and resized to 1024 \(\times\) 1024 pixels using nearest neighbor interpolation [24], which calculates the value of the target pixel with linear interpolation between the four nearest neighbor pixels in the original image. Subsequently, the max/min normalization method was applied to each image, and partial results of the normalization process are depicted in Figure 2. This normalization ensures that the medical images have a consistent grayscale representation, facilitating the detection of features within the images. Furthermore, the images were enhanced using the contrast-limited adaptive histogram equalization (CLAHE) algorithm to improve contrast and provide a clearer visualization of the feature details [25]. This approach avoids the potential problem of noise enhancement associated with the adaptive histogram equalization (AHE) method by constraining the range of contrast enhancement. The advantage of using CLAHE is that it achieves effective contrast enhancement without introducing excessive noise.
# Wireless Communication Technologies for Smart Grid Distribution Networks +
## 4 Previous Studies on Selecting Suitable Technologies for Power Line Monitoring
network indicated an average noise level of around \(-90\) dBm for indoor environments and \(-105\) dBm (of constantly changing) background noise for outdoor environments. The results also showed that a previously existing microwave signal (from a microwave in the study), led to \(15\) dBm interference in the \(2.4\) GHz band. Also, interference of \(802.11\) b was caused by the overlapping band. The final link-quality measurements were determined using three metrics: the Packet Reception Rate (PRR), RSSI, and Link-Quality Indicator (LQI). The latter is also known as the chip error rate. The distance from receiver to sender varied from \(1\) to \(20\) m. The power level of each sensor was \(-25\) dBm and the packet size was \(30\) B, sending \(200\) data packets at a rate of \(2\) packets per second. The results showed that the PRR (ratio of the number of successful packets to the total number of packets transmitted over a certain number of transmissions) strongly correlated with the LQI. Hence, the LQI is a good indicator of the packet reception probability in this kind of experiment. The LQI ranged from \(50\) to \(110\).
## 3 Deliberate Attacks on IECPS
### Physical Attacks  
The foundation of IECPS is the physical system, and the safe and stable transmission of all energy depends on the integrity of physical equipment. Therefore, physical facilities are a prime target for attackers. In IECPS, attackers gather information on the infrastructure and critical equipment of the integrated energy system. They identify targets such as substations, natural gas stations, and transmission pipeline communication equipment, then deploy graphite bombs, drone strikes, and laser jamming to damage physical assets [67]. Graphite bombs disrupt power systems by dispersing highly conductive graphite fibers that attach to power infrastructure, resulting in short circuits or insulation breakdowns, which can lead to catastrophic equipment failures and widespread power outages [68]. Beyond graphite bombs, other types of explosive devices, including drones equipped with bombs, can be deployed to target energy systems, enabling precise strikes on critical infrastructure [69]. Laser jamming refers to an attack technique that utilizes high-energy lasers to disrupt and damage sensitive measurement components within energy systems, potentially resulting in inefficient operation and significant economic losses. In addition to the aforementioned methods, some unscrupulous individuals engage in power theft by tapping into wires, resulting in non-technical losses to the operator [70].  
Since physical attacks often result in infrastructure damage, attack modeling often assumes that the attack results in a functional defect or complete loss of the target facility. Consequently, physical attacks can be modeled according to the following equation:  
\[\big{(}1-\tau b_{q}\big{)}F_{q},q\in I_{\text{P}}, \tag{23}\]  
where \(\tau\) is a factor between 0 and 1 characterizing the degree of impact of the attack on the device's functionality; \(b_{q}\) is an attack variable that takes the value of 1 if the device \(q\) suffers from an attack, and 0 otherwise; \(F_{q}\) characterizes the specific functionality of the device \(q\); and \(I_{\text{P}}\) is the set of physical devices of IECPS.  
During an attack, the attacker's resources are constrained due to limitations in their attack capabilities, preventing them from damaging the entire energy system:  
\[\sum_{q\in I_{\text{P}}}b_{q}\leq N_{\text{a}}^{\text{max}}. \tag{24}\]
# An Efficient Steganographic Protocol for WebP Files
## 2 Materials and Methods
### Data-Based Methods
#### 2.4.1 Transparency  
The WebP format supports transparency, in both lossy and lossless modes. The interesting option used in this method is \"exact\", described as follows.  
-exact preserves RGB values in the transparent area; default = off  
Normally, the WebP encoder skips bytes in transparent areas of the carrier to save space. However, with this option enabled, it is possible to use these locations to conceal some data. The secret may be embedded in each transparent pixel. Then we are able to achieve the capacity of 3 bytes per pixel. In such a case, the \"lossless\" option is also required to avoid the destruction of hidden data. Another approach is to conceal graphic data by pasting the secret image into the transparent area, preserving transparency.  
The secret is not visible on the preview, but the method does not provide much security (the more data are hidden, the bigger the file becomes). On the other hand, it has satisfactory capacity and does not visually change the container. Additionally, the presented technique is also applicable to PNG images. In PNG images, the container modification method of embedding in transparent pixels works similarly as in WebP files. The embedding area consists of all transparent pixels. Secret data are translated to bytes, and for each color component with alpha channel equal to zero, one byte is concealed. This means that a single pixel can hold three bytes of secret data. The secret message length should be less than or equal to the number of transparent pixels to be able to conceal it. If the capacity is greater than the secret message length, the data may be spread over available space. The recoveringprocess is carried out in reverse. First, secret bytes are read from transparent areas, and then they are shaped into the message. When the stego image is open in graphical software, the hidden pixels are not visible. But this technique causes the file size to grow, which gives a clue that something may be hidden inside. This method can also be used to conceal a digital image instead of text or binary data. Then, to reveal the hidden image, the receiver needs to remove the alpha channel and to save the resulting image.
# The Response of NDVI to Climate Change in the Lowest and Hottest Basin in China
## 1 Introduction
These divergences suggest that the response relationship between NDVI and climatic factors may be influenced by various factors such as regional geographical location, climate type, and vegetation type, exhibiting significant regional differences. As a quintessential example of low-altitude extreme environments in the arid regions of China, the Turpan-Hami Basin, characterized by its unique geographical location (low altitude) and extreme climatic conditions (e.g., high temperatures, low precipitation, and high evaporation), may exhibit distinct vegetation-climate response mechanisms compared to other regions. Currently, systematic research on the spatiotemporal differentiation characteristics of NDVI in the Turpan-Hami Basin and its responses to temperature, precipitation, and PET is limited. To address this gap, this study develops a multi-scale spatiotemporal analysis framework and employs grid data to quantitatively analyze the spatiotemporal coupling relationship between vegetation and climate characteristics in the Turpan-Hami Basin. The objective is to elucidate the dynamic evolution patterns of the climate-vegetation feedback mechanisms at this unique regional scale, thereby providing a scientific basis for adaptive management of ecosystems in arid areas. The major contributions of this research are as follows: (1) deepening the understanding of vegetation-climate response mechanisms in extremely low-altitude environments of China's arid regions and (2) offering regional empirical references for global arid-zone ecosystem conservation and management. The paper is organized as follows: Section 2 details the data and methods, covering the study area, data sources, preprocessing, and analysis methods. Section 3 presents the results, including the spatiotemporal distribution of NDVI and vegetation-climate factor response analysis in the Tuha Basin. Section 4 discusses the results, comparing them with previous studies and exploring discrepancies. Section 5 concludes by summarizing the key findings and reiterating the core contributions.
# Review on the Electrical Resistance/Conductivity of Carbon Fiber Reinforced Polymer
## 4 CFRP Conductivity Measurements and Techniques for Non-Destructive Testing Applications
### Delamination Measurements Based on Electrical Conductivity  
The basic principle of a delamination test is that cracks and damages are obstacles in an electrical current path. Therefore, such cracks and damages can increase the electrical resistance. The size, shape, and orientation of such damages/cracks determine the resistance change, which thus can be used as a detection indicator of delamination [121].  
Due to compound material structures, many destructive methods and non-destructive techniques have been developed for CFRPs [125], including eddy current testing (ECT) [39; 126; 127], inductive thermography [128], and electrical resistivity change methods [129].
# Effect of Vinyl Flooring on the Modal Properties of a Steel Footbridge
## 4 Assessment of the Dynamic Behavior of a Laboratory Footbridge without and with the Vinyl Flooring
### Discussion of the Results  
In this manner, the non-structural damping ratios, \(\zeta_{ns,j}\) (being \(j\) the number of the considered vibration mode), due to the vinyl flooring can be determined. Table 4 shows the non-structural damping ratios, \(\zeta_{ns,j}\), for the five considered vibration modes. These non-structural damping ratios have been obtained by substracting of the values of the experimental damping ratios of the footbridge without the vinyl flooring from the values of the experimental damping ratios of the footbridge with the vinyl flooring.  
Figure 7: Singular values decomposition of the spectral densities for all the test set-ups and experimental natural frequencies identified by the stochastic subspace identification (SSI) algorithm for the laboratory footbridge: (**a**) without the vinyl flooring and (**b**) with the vinyl flooring [(20)].  
Finally, Figure 8 illustrates the variation of the experimental damping ratio of the laboratory footbridge without and with the vinyl flooring in terms of the considered vibration mode. The average experimental damping ratios of the footbridge without and with the vinyl flooring, 0.328 and 2.397% have been included in Figure 8 as references. The average non-structural damping ratio of 2.069% has also been obtained and included in Figure 8. At this point, two main results may be obtained from the analysis of Figure 8: (i) the effect of the vinyl flooring is greater on the damping ratios of the vertical and torsional vibration modes than on the lateral and longitudinal vibration modes and (ii) the effect on the damping ratios of all considered horizontal vibration modes, lateral and longitudinal, is similar.  
According to these results, the vinyl flooring can be taken into account as a passive damping system in order to reduce the pedestrian-induced vibrations in steel footbridges. The effective implementation of this pavement allows increasing the damping ratios of steel footbridges with several advantages in comparison with the conventional external passive damping devices as, for instance, a smaller budget and a better integration with the aesthetics of the structure.