esa-sceva/satcom-chunk-collection huggingface dataset:
# Network Lifetime Improvement through Energy-Efficient Hybrid Routing Protocol for IoT Applications
## 4 Proposed Hybrid PSOGA
### Genetic Algorithm-Based Routing  
GA is a search-based optimization approach that employs the principle of genetics and natural selection [27; 28; 29]. It is often used to provide optimal or suboptimal solutions to challenging real-life problems that might take a longer time to resolve. The steps performed for applying a GA to solve an energy optimization problem in a WSN are given as follows:  
* Step 1: Initially, the chromosome is encoded in an efficient manner.
* Step 2: In order to maximize the network lifetime, the individual with the highest fitness function value is taken in the upcoming generation.
* Step 3: The mating pool of good individuals is created through selection.
* Step 4: Among the pool of good individuals, two parents are selected to exchange their genes to create new offspring. The newly created offspring are expected to have better fitness values than the parents.
* Step 5: Mutation is also employed to achieve diversity in the offspring generated during the crossover.
# GNSS Applications to Assess Performance in Olympic Sailors: Laser Class
## 4 Discussion  
The aims of this study were to investigate the technical (VMG) and tactical (distance and maneuvers) variables in order to determine their relationship with performance in the Laser class on the upwind, broad reach, and downwind courses and to identify sex differences, using GNSS devices. To our knowledge, this is the first study to evaluate technical and tactical performance in the laser class in a regatta, and it is also the first study to analyze the three types of courses developed during the competition (upwind, downwind, and broad reach). The results of our study show that the most successful group of sailors (male and female) sailed faster (VMG) in the upwind and downwind legs compared to the less successful sailors. In previous studies, it has been observed that the elite sailors in the RS:X windsurfing class had a higher VMG on the upwind and downwind courses [8, 9]. This could indicate that these sailors have a better technical level, which would allow them to handle the boat more efficiently to reach higher speeds, thus keeping the boat in a planning condition, thereby reducing its hydrodynamic resistance [28, 29]. Some studies have shown that more successful sailors are faster and have a better pointing angle, which can be achieved only with a higher level of physical performance, as it is known that efficient hiking is related to boat speed and boat handling performance [12, 30]. Therefore, and on the basis of our results, we could assert that, in our Laser class sailors, the higher the level of the sailor, the greater the VMG achieved in the upwind and downwind courses. Similarly, the greatest male sailors achieved a higher VMG in upwind and downwind compared to low-level sailors, and this difference was greater when the group of females was analyzed in upwind, downwind, and broad reach. Analyzing the speed in the different courses evaluated, it was observed that the sailors were faster in the broad reach course, followed by downwind and upwind. These results are in line with those obtained in kitesurfing class sailors [15, 31]. This is the first study to determine the fastest course in the Laser class. Regarding distance, and for the entire sample (males and females), differences between groups were only found in upwind. According to our results, other studies assert the importance of the upwind course, since elite sailors travel a shorter distance in this leg, and this is where they can establish a greater difference in the position of the race compared to other competitors [32, 33]. Moreover, previous studies have shown that higher-level windsurfing sailors finished the race with a shorter distance in upwind [19]. In agreement with these results, it was observed that, in the male group, elite sailors covered a shorter distance in upwind, although distance was not a variable that differentiates performance in the group of females in any of the analyzed courses. A study with RS:X class sailors, where 94 races were analyzed (47 males' races and 47 females' races), it was observed that
## 1 Introduction
Most of these studies focus on the mathematical way to obtain low dynamic stiffness [14; 15], and some show experimental results on prototypes for various industrial applications as [16] or as [17; 18] to improve the comfort seat suspension of the vehicle. The performance of more recent systems is demonstrated experimentally under harmonic and random conditions [19]. Shock excitation is also investigated [20] and specifically using a buckled beams setup [21]. As examples of other configurations, negative stiffness can be used to bring damping to composites [22; 23] or can be inserted as magnets, as in [24; 25]. As part of vibration control solutions, different types of negative stiffness systems are reviewed by [19; 26]. As for more recent developments, these devices are used in periodic arrangement of beams to produce negative-stiffness honeycombs [27; 28; 29; 30] and negative-stiffness metamaterials providing band gaps [31; 32]. From this literature review, a widely used approach is to formulate the dynamic behavior through the equation of motion of the equivalent spring-mass system, in which the stiffness parameters are considered as the equivalent stiffness of the structural elements. This approach is well suited to assess the nonlinear behavior since the stiffness is supplemented by higher-order terms, either derived analytically or numerically using Taylor expansions. The obtained equation is generally reduced to a Duffing oscillator, whose nonlinear resonance and unstable nature are extensively documented. Deriving a dynamic beam model would be of interest because solving the beam problem would encompass more realistic phenomena. In fact, the negative stiffness components are rarely ideal springs but rather structural elements such as elastic rubber rods, slender beams or bar systems, or repulsing magnets. For some operating regimes, even a linear one assuming small displacements, the ability to obtain an analytical description of such a system based on a bending model would be beneficial. The objective of this work is to present some design rules and equations associated with the description of a negative stiffness resonator prototype. The design under study is largely inspired from [6; 33]. The analysis is complemented by finite element comparisonsperformed on the different components. Experimental measurements are finally conducted on a mock-up and demonstrate the tunable aspect of the resonator with respect to different axial loads. This paper is organized into three sections. A primary description of the structure under study is introduced in Section 2, together with the underlying physics and associated mechanisms. Along with the analytical model comes the numerical investigation in Section 3. Particularly, force-displacement relations and eigenfrequency computations are presented in order to confirm the validity of theoretical predictions. Finally, Section 4 describes experiments conducted on a mock-up of the resonator. Measured frequency responses show the softening effect as axial load increases and exhibit similar trends to the theoretical model, justifying its consistency.
# High-Aspect-Ratio Silicon Metasurfaces: Design, Fabrication, and Characterization. _Applied_
###### Abstract  
Unrestricted manipulations on terahertz (THz) waves are highly desired in integration-optics, but THz devices based on conventional materials are usually bulky in size. Although all-silicon metasurfaces have exhibited great capabilities in manipulating THz waves, most of them are less efficient and have limited functionalities. In this work, we first design a silicon meta-atom structure consisting of a high-aspect-ratio (AR) micro-pillar that exhibits nearly perfect transmission and large transmission phase of THz wave, and systemically study how the fabrication quality (e.g., steepness of the sidewall and the vertical thickness distribution) may influence the final performance of a functional metasurface constructed with such meta-atoms. After experimentally examining how two working phases in the deep-reactive-ion-etch technology (i.e., the etch and passivation phases) influence the quality of the fabricated meta-devices, we develop an optimized Bosch process to realize high-AR (\(\sim\)20:1) all-silicon metasurfaces by balancing two working phases. We finally design/fabricate a high-AR silicon metasurface and experimentally demonstrate that it behaves as a high-efficiency half-wave-plate for THz waves in transmission geometry. Our results pave the avenue to realize ultra-compact THz meta-devices with high performance in transmission geometry, which is highly desirable for THz applications.  
transmissive metasurface; Bosch process; terahertz; polarization control; high aspect-ratio _Applied_  
_sciences_
# Qom--A New Hydroologic Prediction Model Enhanced with Multi-Objective Optimization
## 1 Introduction
For validation purposes, six realistic hydrographic scenarios comprising river basins, located in different regions of Spain, USA, Brazil and Argentina, have been modeled and evaluated with different size conditions, climates, topographies, heterogeneous soils and with a series of very short time periods of 10, 15, 30 and 60 min and 24 h. The results are mathematically validated by three gauges parameters and exponential functions that relate evapotranspiration, surface stored water, water stored in the soil with the infiltration and percolation processes. The conducted experimentation shows that the combination of Qom with the multi-objective based calibration procedure can provide experts with successful trade-off solutions, which minimize the prediction errors of simulated streamflows with regards to those observed in real-world basins. The remainder of this paper is organized as follows. Section 2 provides the algorithmic background. Section 3 presents a series of related works in the state-of-the-art. In Section 4, the proposed Qom hydrologic model is detailed and formulated in the form of multi-objective optimization problem. Experimental results and discussions are presented in Section 5. In Section 6, a series of discussions have been included. Finally, conclusions and future work are commented in Section 7.
## 3 Proposed Protocol Architecture
### Border Router Solicitation and Advertisement Message Format  
Figure 12 depicts the router solicitation (RS) and router advertisement (RA) message format of IP-WSN. Figure 12(a) shows the RS message which is sent by an IP-WSN sensor node. The IEEE 802.15.4 MAC header's source and destinations address set to the source and destination sensor node's MAC address. Dispatch of IP-WSN addressing header indicates the compressed IPv6 header. Header compression section compresses different fields of IP-WSN addressing header. Router solicitation message's RS options enable IP-WSN gateway to obtain the sensor node's MAC address, link-local address and sensor node's ID. The RA message format has two options such as home network prefix (HNP) and address options. The HNP options are used to emulate a IP-WSN sensor node's home network.
###### Abstract
The deformation and damage process of prefabricated jointed rock masses under freeze-thaw cycles can be divided into four stages: compaction, elastic deformation, pre-peak instability, and post-peak instability damage [16]. Additionally, the mechanical properties of defective red sandstone are weakened due to the pore pressure from free water [17]. During stress, defective rocks primarily exhibit shear cracking, and at low crack inclinations (a < 45 degrees), there is a notable formation of concentrated zones [18]. The previously mentioned research has extensively investigated various aspects of jointed rock, encompassing its failure modes, deformation characteristics, and the influence of mechanical parameters. Most scholars have directed their research efforts toward jointed rock masses, with a predominant focus on damage mechanics and fracture mechanics. They have explored the effects of various spatial distributions, such as angles and widths, as well as the filling characteristics of joints on the mechanical properties of rock masses. Additionally, they have delved into patterns of macro and micro-scale crack propagation. Nonetheless, there is a notable scarcity of research on the deformation and evolution processes of jointed rock masses with multiple joints, particularly in terms of analyzing their mutual interactions. A deeper, more comprehensive analysis in this realm is clearly warranted. This study entails the design of red sandstone specimens with dual joints, positioned at a 45-degree dip angle, varying in length. Cement slurry is used to fill these dual joints, allowing for the differentiation between the jointed and intact regions. Subsequently, laboratory compression tests are conducted to investigate the slip, propagation of secondary cracks, and distribution patterns of deformation fields in the dual-jointed rock during the loading process. Furthermore, numerical simulations of jointed rock are executed to clarify the fracture and instability characteristics influenced by joint response between jointed and intact regions in 45-degree dual-jointed rock. The study also encompasses the identification of physical data at critical nodes throughout the loading process.
## 4 Engineering Application
### Support Test of the FMCFR in the 8# Coal Seam of XH Coal Mine  
After the excavation of the 815 working face transportation roadway in the 8# coal seam of XH Coal Mine, industrial tests were carried out to apply the synergistic support system of \"LDAGF\" on a 300 m long section of ESEFMCFR. Monitoring devices were installed during the industrial tests to collect data. The on-site test adopted an anchor rod dynamometer and a tunnel surface convergence instrument. Then, the support effect for the 815 working face transportation roadway was evaluated and analyzed.  
Analysis of the Monitored Data on the Mine Pressure  
Monitored data on the mine pressure of the transportation roadway in XH Coal Mine mainly include the stress of anchor cables and the displacement of the roadway surface.  
The stress of cables was monitored by an online cable hydraulic pillow. The stress variation in the cables monitored by the pillow after the application of the synergistic support system is shown in Figure 12. In the monitoring period, roadway mining disturbance occurs, so the stress of the anchor cables decreases to a certain extent and then rises. Overall, the stress of the anchor cables gradually rises and then stabilizes, reaching its maximum value of 135 kN. This indicates that the anchor cables in the synergistic support system of \"LDAGF\" can mobilize the bearing capacity of SR well and lead to stable stress on the cables.  
The displacement curves of the roof, floor and two sides of the 815 working face transportation roadway in XH Coal Mine are shown in Figure 13. During the monitoring period, the deformation of roadway SR varies significantly within 25 days after excavation, and tends to stabilize on the 35 th day. Before the roadway stabilizes, the displacement value of the roof and floor is 117 mm, with the average displacement speed being 3.34 mm/d. These two parameters of the two sides are 66 mm and 1.89 mm/d, respectively. During the whole monitoring period, the synergistic support system can greatly mobilize the bearing capacity of the SR and effectively control SR deformation.  
Figure 12: Curve of force on and variation in anchor cables over time.  
Evaluation on the Support Effect  
According to the above data, the synergistic support system of \"LDAGF\" can effectively control the serious deformation of the ESEFMCFR. Moreover, the synergistic action of different supporting structures can lead to appropriate stress on the anchor cables and realize the expected effect. The synergistic support system can fully mobilize the overall bearing capacity of the SR and effectively resist roadway deformation.
# Sign Language Sentence Recognition Using Hybrid Graph Embedding and Adaptive Convolutional Networks
## 3 Proposed Hybrid Graph Embedding and Adaptive Convolution Networks
### Feature Extraction
The benefits of this fusion process are detailed in Figure 2c, which demonstrates the way multiple sensor inputs contribute to a more robust sign language recognition framework. To ensure consistency across sensor data, normalization is applied before fusion. This process involves scaling values to a common range, typically between 0 and 1, to standardize formats and improve comparability. Data fusion is then applied to integrate previously separate datasets into a single, more complete representation. Overall, data redundancy is minimized, improving the efficiency of the analysis during the fusion process. By combining motion data from multiple sensors, the system compensates for the limitations of individual sensors, which may capture only partial data despite their effectiveness. This method enhances the comprehension of sign language gestures by constructing a richer representation of movement and hand positions. Additionally, fusion techniques mitigate noise, disturbances, and other sensor errors, improving accuracy and robustness in sign language recognition.
## 2 Model and Method
### Two-Phase Flow Model  
The VOF model is used to capture the complex oil-air two-phase distribution characteristics in the under-race lubrication ball-bearing cavity. It uses a volume fraction function to represent the location of different fluid-free surfaces and the volume occupied by different fluids, better capturing the interface between different phases [22]. In the VOF method, a  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Number of Grids** & **Oil Volume Fraction** \\ \hline
2,286,395 & 0.0133 \\
3,143,919 & 0.0135 \\
4,164,156 & 0.0136 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Mesh independence verification.  
Figure 3: Computational mesh structure and boundary condition.  
Figure 2: Ball bearing fluid domain.  
volume fraction \(\varphi_{oil}\) is used to define the oil phase volume fraction; the volume fraction of the air phase is \((1-\varphi_{oil})\). If \(\varphi_{oil}=1\), it means that the cell is full of oil; if \(\varphi_{oil}=0\), it means that the cell is full of air; if \(0<\varphi_{oil}<1\), it means that the cell is in an oil-air two-phase mixing state. The volume fraction \(\varphi_{oil}\) can be solved by the following equation:  
\[\frac{\partial}{\partial t}(\varphi_{oil}\rho_{oil})+\
abla(\varphi_{oil} \rho_{oil}\mu_{oil})=S_{\alpha_{oil}}+\left(\dot{m}_{\alpha a}-\dot{m}_{a \alpha}\right) \tag{1}\]  
where \(\rho_{oil}\) is the oil density, \(\dot{m}_{\alpha a}\) is the mass transfer rate from the oil phase to the gas phase per unit volume, \(\dot{m}_{a\alpha}\) is the mass transfer rate from the gas phase to the oil phase per unit volume, and \(S_{\alpha_{oil}}\) is the source term defined by the volume fraction equation. The relationship between the volume fractions of the oil phase and gas phase is as follows:  
\[\varphi_{oil}+\varphi_{air}=1 \tag{2}\]  
The equivalent density and viscosity of oil-gas two-phase can be expressed as follows:  
\[\rho=\varphi_{oil}\rho_{oil}+(1-\varphi_{oil})\rho_{air} \tag{3}\]  
\[\mu=\varphi_{oil}\mu_{oil}+(1-\varphi_{oil})\mu_{air} \tag{4}\]
## 2 Relative Humidity
### Quality Parameters and Environmental Parameter Analysis  
#### 3.2.1 Quality Parameter Results Analysis  
Since the variety of strawberry quality parameters, the changes in post-harvest strawberry quality can be reflected from all different angles. The sensory evaluation is a comprehensive assessment indicator of the post-harvest fruit quality [29]. Furthermore, fruit hardness and weightlessness are both important indicators for quality assessment, especially the weightlessness rate of 5%, which is often used to determine whether fruits and vegetables still have commercial quality [30]. Moreover, strawberry fruit's flavor and commodity value are related to the sugar-acid ratio [31], and the degree of fruit ripeness and aging can be reflected with relative conductivity. The vitamin C (VC) content in strawberries can indicate the nutritional value of the fruit, while the L* value indicates the brightness change of the strawberry fruit [32].  
This paper measured the quality parameters of the Red Face strawberry at 0, 5 and 20 \({}^{\circ}\)C. The sensory evaluation standard was nine points for fresh strawberry fruits when they were just harvested, and five points for the limit of strawberry commodity; the weightlessness rate was measured by weighing method; the hardness was measured by GY-4 digital fruit hardness tester; the VC content was measured by molybdenum-blue colorimetry; the sugar-acid ratio was calculated by the ratio of soluble solids to tittatable acid; the relative conductivity was measured by conductivity meter; the L* value was measured by CR-400 colorimeter with selecting standard D65 light source and standard whiteboard [33]. The results are shown in Figure 7. It could be seen that with the storage time prolongation, the sensory evaluation, hardness, VC content, chromatic aberration, and the sugar-acid ratio of the Red Face strawberry showed a general downward trend. In contrast, the relative conductivity and weightlessness rate showed an upward trend. The changes in these quality parameters indicated that the strawberry fruits were decaying gradually. With the storage temperature going up, the rate of seven quality parameters of the Red Face strawberry change accelerated gradually, and the rate of fruit decay accelerated as well. Significantly, at the storage temperature of 20 \({}^{\circ}\)C, the sensory evaluation of the Red Face strawberries had been reduced to less than 5 points on the fourth day alone, and the fruit was dull in color, atrophic and lost its commerciality. Therefore, the temperature has a significant impact on the quality change of post-harvest strawberries.
## 2 Materials and Methods
### Satellite Data
#### 2.4.2 Modis Evi  
The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra (originally known as EOS AM-1) and Aqua (originally known as EOS PM-1) satellites have been widely employed in plant growth observation across extensive geographical regions [45; 63; 64; 65; 66; 67]. MODIS provides spatial resolutions of 250 or 500 m and a temporal cadence of 1-2 days, facilitating global-scale dynamic plant growth monitoring.  
As presented in Table 2, this study obtained MODIS-derived EVI from the MOD13C1 (Terra) and the MYD13C1 (Aqua) Version 6 product spanning from 2018 to 2022. Combining these two daily 16-day composite datasets, a corresponding EVI time series was generated at an 8-day resolution. The spatial resolution of the EVI data are set at 0.05\({}^{\circ}\), aligning with the spatial resolution of TROPOMI SIF data for a consistent resolution-level comparison.