esa-sceva/satcom-chunk-collection huggingface dataset:
# Internet of Vehicles for Sustainable Smart Cities: Opportunities, Issues, and Challenges
## 7 Wireless Technologies in IoV
### Short-Range Static Communications  
#### 7.3.1 Bluetooth and Bluetooth Low Energy (BLE)  
The BLE technologies are precisely suited for short-range communication and are well-suited to connect the devices within the confines of a vehicle. Bluetooth and BLE are important means of creating in-car connectivity, enabling the systems on board to communicate with each other [101]. Modern systems enable data transmission to allow users to wirelessly stream audio, share data, and access entertainment features. In addition, Bluetooth and BLE facilitate the simple combination of smartphones with automobiles, making it possible for hands-free calling, playing music, and syncing data. These technologies are extremely adaptable and necessary for enabling a connected and interactive in-vehicle environment where devices communicate efficiently to create a more convenient, entertaining, and better user experience.
###### Abstract  
Additive manufacturing (AM) is often used for prototyping; however, in recent years, there have been several final product applications, namely the development of polymer-metal hybrid (PMH) components that have emerged. In this paper, the objective is to characterize the adhesion of single-lap joints between two different materials: aluminium and a polymer-based material manufactured by fused filament fabrication (FFF). Single-lap joints were fabricated using an aluminium substrate with different surface treatments: sandpaper polishing (SP) and grit blasting (GB). Three filaments for FFF were tested: acrylonitrile butadiene styrene (ABS), polyamide (PA), and polyamide reinforced with short carbon fibers (PA + CF). To characterize the behaviour of these single-lap joints, mechanical tension loading tests were performed. The analysis of the fractured surface of the joints aimed to correlate the adhesion performance of each joint with the occurred failure mode. The obtained results show the impact of surface roughness (0.16 \(<\) Ra \(<\) 1.65 \(\upmu\)m) on the mechanical properties of the PMH joint. The ultimate lap shear strength (ULSS) of PMH single-lap joints produced by FFF (1 \(<\) ULSS \(<\) 6.6 MPa) agree with the reported values in the literature and increases for substrates with a higher surface roughness, remelting of the primer (PA and PA + CF), and higher stiffness of the polymer-based adherent.  
fused filament fabrication; polymer-metal adhesion; single-lap joints; carbon fiber +
Footnote †: journal: Applied Sciences
# RT Engine: An Efficient Hardware Architecture for Ray Tracing
## 2 Overall System Architecture
### Basic Design Decision  
There are many decisions to be made in our design, which we will describe next.  
**Domain-specific architectures:** A more hardware-centric approach is to design architectures tailored to a specific problem domain and offer significant performance (and efficiency) gains for that domain. This design approach exploits more efficient parallelism for the specific domain [26]. This design can speed up some applications compared to running the entire application on a general-purpose CPU. DSA can perform better because they are better suited to the application's needs. In addition, DSAs can make more effective use of the memory hierarchy. Memory access has become much more costly than arithmetic computations, as [PERSON] [27] noted.  
**Acceleration structure:** Many types of acceleration structure research focus on kd-tree and BVH. In the last two decades, the bounding volume hierarchy (BVH) has become the de facto standard acceleration structure for ray-tracing-based rendering algorithms [7]. The BVH traversal algorithm usually occupies less memory bandwidth and has the characteristics of a compact traversal state. NVIDIA [14] and Imagination [15] GPUs also choose BVH as an acceleration structure in the industry. We choose binary-based BVH in our design. It can effectively reduce hardware overhead and design costs compared to other kinds.  
**Per-ray traversal:** There are two ways to determine ray-tracing traces. Packet traversal means a group of rays following the same tree path. This is achieved by sharing the traversal stack among the ray, which means that some rays will traverse those nodes which will not intersect. The other is per-ray traversal, which allows each ray to traverse independently, traversing the node's children only when the node intersects with the ray. Each ray requires a separate traversal stack to store the ray's data. Our design chooses the second way [7].  
**Primitive type:** We use only triangles as the primitive type. This choice can improve system performance and simplify designs because this method can eliminate branches of different graphs. Therefore, other graphics before rendering should be converted into triangles, just like rasterization-based GPU processing methods.  
**First-hit traversal:** This approach is the most widely used and is indispensable for computing the radiance at a shading point, which finds the nearest object in the direction of a ray from its origin. In binary-based BVHs, this approach can efficiently push the farther intersected node onto a stack and visit the closer one first [7].
## 5 Key 6G Technologies
### Improved Wireless Interface  
#### 5.2.1 New Modulation  
The need for different types and complex application settings becomes clear when considering 6G's ambition of full applications, all spectra, global coverage, all senses, strong security, and all digital. To achieve Tbps-level data rates, dense connections, broader coverage, and secure services, different types of new challenges arise in the design of waveforms and modulation.  
Waveform design, critical for communication system performance, must consider the unique characteristics and requirements of various application scenarios. While 5G standards primarily employed high spectral efficiency multi-carrier systems like orthogonal frequency division multiplexing (OFDM), new waveforms tailored for specific 6G scenarios are essential. The heightened frequencies anticipated in prospective 6G scenarios pose formidable challenges, including amplified transmission path loss and the imperative for proficient high-frequency broadband power amplifiers. In addressing these issues, some studies, like the one detailed in [48], explore single-carrier systems with a low peak-to-average power ratio (PAPR). For scenarios with high mobility, transform domain waveforms, such as orthogonal time frequency space (OTFS), offer more accurate descriptions of delay and Doppler [90]. In scenarios requiring high throughput, techniques such as spectrally efficient frequency domain multiplexing [91] and overlapped x domain multiplexing [92] are instrumental in augmenting spectral efficiency. The introduction of integrated sensing and communication (ISAC) technology, discussed later, imposes the need for waveforms enabling simultaneous communication and sensing [93].  
Modulation significantly impacts communication system effectiveness and reliability. While quadrature amplitude modulation (QAM) is widely used in LTE and NR standards, recent years have seen attention shift to other modulation techniques like constellation interpolation, irregular QAM, multidimensional modulation, selected QAM, and IM. These alternatives are noted for their advantages in shaping PAPR, robustness, and gains [94].
# Improving the Efficiency of Energy Consumption in Buildings: Simulation of Alternative EnPC Models
## 2 State of the Art  
### Energy Performance Contracts (EnPC)  
With its origins dating back to the oil crisis of the 1970s, the EnPC emerged as an innovative financing method to reduce energy consumption by recovering the costs of installing and managing energy-saving equipment [10; 11].  
In 2008, a serious financial crisis hit Europe, in particular in the Mediterranean countries, affecting national economies and causing market uncertainties [12]. Although financial resources have been limited since then, the EU's energy efficiency policy, on the other hand, has become increasingly stringent, setting clear and ambitious energy efficiency and CO\({}_{2}\) emissions targets, of which maximum energy conservation in existing buildings and reduction of CO\({}_{2}\) emissions by 80% by the 2050 time horizon stand out.  
According to the [13], an EnPC is defined as one: \"Energy performance contract means a contractual agreement between the beneficiary and the supplier of an energy efficiency improvement measure, verified and monitored throughout the duration of the contract, where investments (work, supply or service) to that extent are paid in relation to a contractually agreed energy efficiency improvement level or other agreed energy performance criterion, financial savings\".  
Today, EnPCs are seen as a market mechanism, or a financing tool, to encourage building owners, both public and private, to conduct energy rehabilitation [6; 14]. Nevertheless, defining it as a purely financial tool is not entirely correct, because the contract also includes technical and maintenance dimensions. Therefore, the EnPC involves the final provision of energy services (lighting, heating, and driving energy), consisting of energy converted by secondary conversion equipment (e.g., radiators and heaters), which can thus be enjoyed directly by customers, without the need for additional conversion processes [15] ([PERSON] and [PERSON], 2015). In Europe, EnPCs have spread widely through schools, hospitals, and government and residential buildings [3], and are certainly a model experiencing growth.
## 6 Simulation-Based Implementation, Experimental Results and Discussion
### Energy Consumption Comparison for E-BIOSARP, BIOSARP and SRTLD  
The average energy consumption results for E-BIOSARP, BIOSARP, and SRTLD are compared in Table 7. Figure 12 shows that the consumption of battery power needed for SRTLD to process the packets is higher than that needed for E-BIOSARP. The latter is close to BIOSARP in terms of the energy required to process a packet. The energy consumption is reduced for E-BIOSARP compared with SRTLD because the data encryption processing time is shorter and there are fewer rediscoveries. Furthermore, Table 7 and Figure 12 show that even with the presence of malicious activity and attacks  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Packet Rate** & **E-BIOSARP without** & **E-BIOSARP with** & **BIOSARP without** & **SRTLD without** \\ (**Packets/s**) & **Malicious Nodes** & **Malicious Nodes** & **Malicious Nodes** & **Malicious Nodes** \\ \hline
1 & 0.536667 & 0.49 & 0.5453 & 0.3833 \\
2 & 0.58345 & 0.553512 & 0.59838 & 0.523411 \\
4.84 & 0.6964 & 0.658167 & 0.7054 & 0.625 \\
6.38 & 0.75 & 0.68094 & 0.7528 & 0.6204 \\
10.64 & 0.7052 & 0.65424 & 0.7154 & 0.61167 \\
**Average** & **0.6543434** & **0.6073718** & **0.663456** & **0.552756** \\ \hline \hline \end{tabular}
\end{table}
Table 6: Delivery ratio comparison.  
Figure 11: Delivery ratio comparison.  
in the network, the level of energy consumption of E-BIOSARP is maintained, demonstrating the efficiency of the proposed mechanism.
# Experimental Verification of the Dynamic Model of Turbine Blades Coupled by a Sealing Strip
## 2 The Test Rig
### Compressed Air System  
The most innovative component of the test rig is the loading system, used to simulate the centrifugal force on the strip. This loading system, based on compressed air, depicted in Figure 2, satisfies the two main technical requirements:  
* loads the strip without any contact, mimicking the effect the centrifugal force has on the strip in real working conditions, e.g., no strip deformations due to point-loading;
* produces a uniform pressure between the strip and the platform, with a value of pressure of 0.3 MPa, which is a realistic value of pressure in turbines with strips.  
A prototype of this loading system has been tested and calibrated as explained in detail in [30]. A pressure regulator controls the pressure, measured by a manometer at the entrance of the air box shown in Figure 2a,b. The compressed air passes through the cover holes of the air box pressing the strip against the blades' platforms. The strip in contact with the blades platforms is visible in Figure 2b. A 1.5 mm gap guarantees that, once the system is on, the lower part of the strip does not touch any portion of the air box. The presence of this gap is a source of pressure loss. For this reason, it was necessary to calibrate the system in order to know which was the effective pressure between strip and platform at a given input pressure. The calibration procedure explained in detail in [30] proved that for an entrance pressure of 0.75 MPa (maximum value available from the compressed air net) the average pressure value at the contact strip-platform was 0.28 MPa.  
The pressure was measured by Prescale Fujifilm LLLW film (Fujifilm Corporation, Tokyo, Japan) between the strip and a support simulating the platforms. The pressure shows minor deviations across the contact patch (\(\approx\)77% of the area has a local pressure value in the (0.25-0.31) MPa range). This value was considered acceptable considering that a realistic value of the pressure due to centrifugal force between strip and platforms is 0.36 MPa.  
Figure 1: (a) test rig functional scheme; (b) photograph of the test rig.
## 2 Materials and Methods
### Statistical Analysis  
The collected data were analyzed using MedCalc Software, version 12.5.0.0 (MedCalc, Ostend, Belgium). In order to examine the distribution of the variables, the Kolmogorov-Smirnov test was performed. Numerical variables that presented a normal distribution were reported as mean values and standard deviations or median and range intervals, whereas variables that presented a non-normal distribution were presented as median and range intervals. Student's \(t\)-test for comparing variables with a normal distribution and the Mann-Whitney test (U) was employed when normality was rejected. The Kruskal-Wallis test was used to detect statistically significant differences between groups of an independent variable. The area under the curve (AUC) was computed and the optimal cut-off values were determined using receiver operating characteristic (ROC) statistics and the Youden J index criterion. The AUC was determined in order to establish the diagnostic accuracy of conventional US and SWE US elastography (for Max, Min and Mean EI values and for the QBox ratio). The sensitivity, specificity, PPV, NPV and accuracy of diagnosis were determined for each test. For all the statistical testing, a \(p\)-value below 0.05 was established to indicate statistical significance.
# Data Analytics for Optimizing and Predicting Employee Performance
## 3 Methods and Results
### Data Preparation
#### 3.3.3 Data Pre-Processing  
Feature scaling is a vital part of data pre-processing, so that we can build accurate and optimal machine learning models. Apart from their contributions to the models' performances, these techniques also help to reduce the impact of outliers by avoiding the domination of those attributes which have a larger value. Feature scaling contributes to datasets that have different ranges or even different units of measurement and where variation existing in the attributes can lead to differences in model performance during the learning process. Some important techniques we need to outline for the feature scaling step are standardization, normalization, and min-max scaling.  
For this research study, we will continue by applying the standard scaler method, which is a method that resizes the distribution of the data and obtains values that have a mean of zero and a standard deviation of one. This method is suitable when the characteristics of the input dataset differ in their ranges or measurement units [26].
# A Review of Blockchain-Based Secure Sharing of Healthcare Data
###### Abstract  
Medical data contains multiple records of patient data that are important for subsequent treatment and future research. However, it needs to be stored and shared securely to protect the privacy of the data. Blockchain is widely used in the management of healthcare data because of its decentralized and tamper-proof features. In order to study the development of blockchain in healthcare, this paper evaluates it from various perspectives. We analyze blockchain-based approaches from different application scenarios. These are blockchain-based electronic medical record sharing, blockchain and the Internet of Medical Things and blockchain-based federal learning. The results show that blockchain and smart contracts have a natural advantage in the field of medical data since they are tamper-proof and traceable. Finally, the challenges and future directions of blockchain in healthcare are discussed, which can help drive the field forward.  
blockchain; healthcare data; privacy; security +
Footnote †: journal: Medical Data Management  
[PERSON] et al. have analyzed a number of papers published between 2016 and 2020 [8]. This article focuses on healthcare application situations and does not focus primarily on the comparison and summary of models. Some blockchain-based healthcare approaches are summarized by [PERSON] et al., but they do not compare these approaches [9]. [PERSON] et al. conducted a model analysis with a unique perspective, looking at both the benefits and threats that technology poses to patients [10]. [PERSON] et al. performed a statistical analysis of the published papers. However, this review did not summarize the techniques [11]. [PERSON] et al. mainly analyze the application of blockchain in oncology medical data, such as drug traceability and oncology data sharing [12]. This study has limitations because only oncology data are analyzed. In this paper, we analyze blockchain-based methods for sharing healthcare data, dividing the technologies into three cases in terms of application scenarios: blockchain-based healthcare data storage and access, blockchain and internet of medical things(IOMT) and blockchain-based federal learning. Each technology is also compared and summarized, and finally, compared with the traditional cryptography-based data sharing methods.  
This paper surveys the latest blockchain-based technologies for sharing and storing medical data and summarizes these technologies. The subsequent structure of this paper is organized as follows: Section 1 introduces the research background and the significance of this paper. Section 2 introduces the basic concept of blockchain. Section 3 introduces the scenarios of blockchain application in medical data sharing, categorizes them into three cases and introduces them in detail. Section 4 analyzes the challenges and opportunities encountered in blockchain in medical data. The fifth section concludes the paper.
# Research on Lane Detection Based on Global Search of Dynamic Region of Interest (DROI)
## 4 Lane Detection and Tracking
### Interpolation of Lane Line Discontinuities  
Due to the existence of dotted lines and worn lane lines, lane line detection cannot be carried out effectively. Therefore, in this paper, the missing points between line segments are filled by linear interpolation [24].  
The first-order interpolation is as follows:  
\[\mathrm{y}=\frac{x_{1}-x}{x_{1}-x_{0}}.y_{0}+\frac{x-x_{0}}{x_{1}-x_{0}}.y_{1} \tag{26}\]  
The quadratic interpolation is given by:  
\[\mathrm{y}=\frac{(x-x_{1})(x-x_{2})}{(x_{0}-x_{1})(x_{0}-x_{2})}.y_{0}+\frac{ (x-x_{0})(x-x_{2})}{(x_{1}-x_{0})(x_{1}-x_{2})}.y_{1}+\frac{(x-x_{0})(x-x_{1}) }{(x_{2}-x_{0})(x_{2}-x_{1})}.y_{2}\, \tag{27}\]  
For generally straight lanes or lanes with small curvature, first-order interpolation can supplement the missing data points. For roads with large curvatures, the quadratic interpolation method can better supplement the data of the missing points.
## 3 Results and Discussion
### Assembling of Particles with Linearly Polarized Beam
When the trapping depth increases, the radii of the particle rings become larger, as shown in Figure 2f. Furthermore, the movement of the total ring structure at the interface can be achieved by shifting the diffraction pattern at the \(x\)-\(y\) plane. When the trapping depth is larger than 3 \(\upmu\)m, the intensity of high order bright fringes and the optical forces decrease drastically at the slide-water interface. The diffraction optical traps become an ordinary three-dimensional optical trap, which can trap the particles only at the focus spot. The confinement capabilities of the diffraction optical traps are related to the particle concentration and laser power. We evaluate the confinement capabilities of the diffraction optical traps by the time required for a complete pattern. The complete pattern means the outermost diffraction fringe has been full of particles. The required times are measured for various laser power and the different concentrations. Figure 3a shows the relation between the required time and laser power for 1 \(\upmu\)m particles at the number concentrations of \(4\times 10^{8}\) cm\({}^{-3}\). The required time decreases linearly with the laser power increasing because the optical gradient force is proportional to the laser power. Figure 3b shows the relation between the required time and particle concentration for a 1 \(\upmu\)m particle at the laser power of 820 mW. The required time decreases when the particle concentration increases. The larger particle concentration  
Figure 2: Images of the assembly formed by the diffraction pattern. (**a**) before the laser working; (**b–d**) generation of particles ring structure at the interface; (**e,f**) the radius of rings varied. The laser beam is irradiated perpendicularly to the imaging plane, and the power is 450 mW. The number concentration of 1 \(\upmu\)m particles in the solution is \(2\times 10^{8}\) cm\({}^{-3}\); scale bar, 10 \(\upmu\)m.  
means that there are more particles around the diffraction fringes, so the bright fringes have more opportunities to trap the particles and shorter time is required to form a complete pattern.
## 5 Results and Discussion
### Comparison of Compressive Strength

Table 6: Comparison of compressive strength under ambient and marine exposure conditions. Figure 7: Compressive strength of ambient and marine exposed specimens. geopolymeric solid bonds, the salt content was found to have a negligible effect on the degradation of the specimens in the early stages of exposure to harsh weather conditions.