esa-sceva/satcom-chunk-collection huggingface dataset:
# Application of Acoustic Emission Technique in Landslide Monitoring and Early Warning: A Review
## 3 Fundamentals of Acoustic Emission Technique
### Attenuation Characteristics of Acoustic Emission in Soils  
Attenuation refers to the exponential decay in AE signal amplitude as it propagates away from its source location within a material. It poses a major impediment for employing AE techniques for long-range subsurface monitoring applications in geo-materials exhibiting high damping capacities. Understanding attenuation properties specific to soils proves crucial to optimize instrumentation for overcoming restricted detection limits.  
Attenuation arises due to factors like geometric spreading, scattering, mode conversion, material intrinsic damping from internal friction, and macro/micro structural heterogeneities [112]. It depends jointly on frequency, confining stresses, and soil mineralogical-textural attributes through their influence on elastic moduli and fabric anisotropy.  
[PERSON] et al. [115] discovered that in saturated soils, the interconnected isotropic water phase promotes the transmission of acoustic waves with reduced attenuation, resulting in an increased detection of AE events. In contrast, in dry or unsaturated soils, the propagation of acoustic waves becomes more intricate due to the existence of discontinuities like particle-particle contacts and interfaces between particles and air or water. Consequently, fewer AE signals are identified compared to saturated soils, and the detection sensitivity is influenced by the frequency spectrum of the emitted waves, as varying frequencies experience diverse levels of attenuation during transmission.  
Establishing correlations between AE attenuation and geotechnical parameters, [PERSON] et al. [116] indicated decreasing trends with increasing consolidation stress and void ratio. While attenuation increased hyperbolically with frequency, moisture content exponentially amplified attenuation.  
Attenuation mechanisms remain complex combinations of scattering from void space heterogeneities, grain-to-grain contact impedance mismatches, intrinsic material losses, and moisture influences coupling dissipative fluid motions [117]. Accordingly, reliable attenuation predictions demand calibrated models accounting for predominant physics through multivariable dependencies.  
Overall, significant soil attenuation poses a significant challenge for long-range AE monitoring endeavors. Future studies that combine empirical validations with microstructure-informed numerical simulations incorporating accurate grain characteristics, spatial arrangements, and soil moisture conditions offer potential for predictive attenuation assessments. This approach can enhance the optimization of field sensor placement and the design of instruments tailored to particular geological materials and stress conditions.
# Reconfigurable Multi-Beam Receiver Based on Microwave Photonics Technology
###### Abstract  
A novel multi-beam photonic receiver with a variable beam count has been proposed. The reconfigurable characteristic of the system is enabled with the variable splitters and optical switch arrays. According to the number of beams it is due to receive, the splitter with suitable ports is chosen to split by controlling the optical switch in order to configure the optical path. After splitting, the multi-wavelength optical carriers are sent to the wavelength division multiplexer to combine and complete the multi-beamforming process. Two structures have been designed to realize the reconfigurable function, while the optimized structure is proved by using several benchmarks for comparison. The operation step of the reconfigurable multi-beam receiver is then given. The first simulations validate that the proposed architecture can dynamically receive the multi-beam with a variable number by reconfiguring the state of the optical switch. The second simulation of the influence on the received beam pattern was performed under a different amplitude and phase inconsistency random values. The results show that the amplitude and phase inconsistency will decline the quality of the multi-beam. When the amplitude and phase inconsistency are within limits, the difference in the optical path within the outputs must be balanced and compensated during the proposed system's fabrication and deployment.  
microwave photonic; multi-beam; receiver architecture; reconfigurable Article
## 3 Results and Discussion
### Food Safety  
Fermentation flora [aerobic mesophilic cfu] measured after 21 days were found to be between 5.8 \(\times\) 10\({}^{7}\) cfu/g and 4.1 \(\times\) 10\({}^{8}\) cfu/g, levels that are considered typical for ferrented products. Further details can be found in Table 4. _Escherichia coli_, _Listeria monocytogenes_ and _Salmonella_ spp. were not detected in any of the samples, and the samples were thus deemed safe for consumption. The a\({}_{\mathrm{w}}\) values (0.926 to 0.916), combined with the observed pH values (pH 4.3-4.5) as well as the additional applied hurdles (protective cultures, salt content, smoking, vacuum packaging after drying and storage at 15 \({}^{\circ}\)C), were sufficient to guarantee the food safety of the raw-fermented plant-based salami analogs.  
As noted previously, with increasing pectin concentration in the matrix, both the pH and a\({}_{\mathrm{w}}\) values decreased, which made for a somewhat safer environment in the matrix. This, however, did not prove to be of significance under the tested parameters, since the values achieved during fermentation and drying were dominant here. For more practice-oriented applications it will be crucial to find a good balance between sufficient acidity for a safe product and an appropriate acidity for a mild, pleasant taste similar to the one that traditional raw-fermented sausages provide (-pH 4.8-5.5 [66; 67]). This could be accomplished by use of bacterial strains tailored to the plant-based matrix. Food safety will have to be re-examined then, though, considering that plant-based materials typically show moderate vital cell and spore contaminations with a large variety of strains, including _Listeria monocytogenes_ and _Bacillus_ cereus, due to their cultivation, harvesting and processing conditions [84].
# Application of Simultaneous Symmetric and Cambered Airfoils in Novel Vertical Axis Wind Turbines
## 3 Methodology
### Solution Method  
The continuity and 2D Navier-Stokes equations are solved for both dynamic and static simulations. Transient time dependency is used for both of them. The solvers are pressure based for both simulations. For the dynamic simulations, the rotating domain has a rotational velocity of the rotor. For the static simulation, the rotor zone does not have rotational speed and is fixed at a desirable angle. Boundary conditions are presented in Section 3.1. The pressure and velocity in both simulations are coupled together. For discretization, explicit second order is used for spatial discretization of both dynamic and static simulation. A semi-implicit second order is used for temporal discretization in both simulations. The Reynolds number based on the chord length (\(\text{Re}_{\text{C}}=\frac{\text{U}_{\infty}\cdot\text{C}}{\text{Y}}\)) is more than 57,000 for all of the cases. According to the value of the Reynolds number and the flow behavior close to the boundary layer and far from it, k-\(\omega\) SST is used as a turbulence model [55].  
To find the power coefficient of VAWTs, initially, the torque coefficient (\(\text{C}_{\text{T}}\)) is measured; then, using the tip speed ratio equation (\(\lambda=\frac{\text{C}_{\text{C}}}{\text{C}_{\text{T}}}\)) [13], the power coefficient is obtained [13]. Hybrid initialization is used for initializing the domain. For analyzing the self-starting ability of different VAWTs, the rotor is fixed at rotational angles (\(\Delta\theta\)) ranging from 0\({}^{\circ}\) to 360\({}^{\circ}\) with a step angle of 10\({}^{\circ}\). The calculated torque coefficient is the static torque coefficient. A higher static torque coefficient represents better self-starting ability of the VAWT.
# Microbots Gene Delivery System Based on Bifidobacteria in a Tumor Model
## 4 Discussion
Multiple reports have indicated that tumor blood vessels have structural abnormalities and are interrupted by circular fenestrations with a size of 400 nm to 1-2 microns which allows microbots to be extravasated to the tumor cells [12; 14; 23] since microbots can colonize hypoxic areas of the tumor due to their complex mechanisms [7]. Once in the tumor area, the NCs adhered to the bacterial membrane were released (due to the low pH in the tumor area) and were endocytosed by the tumor cells for the gene expression of the pHRE-Luc vector. Luciferase expression was measured 48 h after IV injection of the microbots that contained 50 \(\upmu\)g of the pHRE-Luc vector. We found higher luciferase expression in the tumor tissue (Figure 6); this is attributed to the hypoxic promoter and the presence of hypoxic response elements that enhance the expression of an adjacent gene (luciferase) under hypoxic conditions [24; 25]. Also, the microbots were compared with two other gene delivery systems: NCs alone and the naked plasmid, and the microbots showed significant differences in gene delivery efficiency. _Bifidobacterium breve_ was used as a vehicle to load NCs and transport them into tumor tissues because it is a non-pathogenic, non-immunogenic bacterium; it is anaerobic and can colonize hypoxic tissues rather than normal tissues and organs. Also, its bacterial membrane rich in peptidoglycans allows chemical modifications to load NCs on its surface [26]. Microbots proved to be a very specific and efficient gene delivery system since the expression of the delivered gene is specific to tumor tissues due to the following reasons: (1) the ability of the microbots to only colonize in tumors and not in other tissues since the bacterium only survives under the ideal conditions, such as hypoxia; (2) the magnetic NCs attached to the microbot membrane are directed by a magnet to the tumor tissue, improving specific transport efficiency; (3) chitosan was used to protect DNA from degradation; and (4) the low levels of oxygen in the solid tumors microenvironment generate the accumulation of HIFs, which can enhance the expression of our pHRE-Luc vector. However, in tissues with normal oxygen, this level accumulation of HIFs does not occur (compared to hypoxic tissues). All the components are biocompatible and safe, and the therapeutic use of Bifidobacteria in humans is in the clinical phase. Our results show that the microbots are a highly specific and efficient gene delivery system and can be used to carry and express genes in specific tissues (tumor tissues). This system can be used for drugs and therapeutic gene delivery due to its specificity, therefore reducing collateral damage to normal cells.
# A Cross-Layer Optimized Opportunistic Routing Scheme for Loss-and-Delay Sensitive WSNs
## 6 Performance Analysis and Comparison
### End-to-End Reliability
When it comes to the far-sink region (T5), the end-to-end reliabilities of the traditional routing method, COOR(P) method, COOR(R) method were respectively 0.342, 0.643, 0.934, which represent a 87.77% and 173.07% increase rate. From a regional perspective, it can be seen from Figure 18b that the COOR method increases the reliability of the network from outside to inside. The reliability of T1 can be regard as the same, while in T2, the traditional routing method, COOR(P) method, COOR(R) method respectively maintained the end-to-end reliability at values of 0.413, 0.438, 0.564, which were a 6.18% and 36.62% increase rate. Furthermore, when the COOR(P) method provided a value of 0.165 in T5, the reliability in the COOR(R) method was still kept at 0.558, while in the traditional method it decreased to 0.062. Figure 17: (**a**) End-to-end reliability of node at different distance under \(r=60\), \(N=2\); (**b**) End-to-end reliability of node at different distance under \(r=70\), \(N=3\); (**c**) End-to-end reliability of node at different distance under \(r=80\), \(N=4\); (**d**) End-to-end reliability of node at different distance under \(r=90\), \(N=4\). Figure 18: _Cont._  
In general, the improvement of the reliability of the outer nodes requires the consumption of the remaining energy in all inner areas, especially when the network is not reliable under the traditional routing method. Specifically, due to the significant increase in the number of data packets brought about by the increase in reliability, the transmission power of the nodes in the near-sink region cannot be increased, so the reliability remains unchanged. As the distance to the sink increases further, the remaining energy is sufficient enough to further improve the performance of reliability. From the perspective of data collection rate, the COOR scheme mainly improves the reception rate of data packets sent by nodes in far-sink region of the network, which are easily lost under traditional routing method.
## 1 Introduction
One couple shall be in polar orbit, the other in an inclined orbit in the order of 65 degrees (exact value to be defined), a configuration called \"Bender\" [10]. The Bender configuration has been shown to recover atmospheric and oceanic disturbing signals, reducing the value of the spectral gravity error curves by orders of magnitude compared to GRACE-FO, because aliasing is greatly reduced. Furthermore, the launch of a Quantum Pathfinder Mission by end of the decade is planned, and the quantum technological breakthrough shall be reached by 2035 with a Quantum Mission for Climate and the Green Deal transition ([PERSON], ESA Quantum Satellite Gravity Consultation Platform, 12 November 2021). This study is an improvement with respect to our previous geophysical performance evaluation of the MOCASS satellite mission [4; 5], which concerned the extension of the glaciers and hydrology from the high Mountains of Asia to the South American continent, and the methodology in the evaluation of the satellite sensitivity to the geophysical gravity signals. Previously, the satellite error curves were compared to the amplitude of the dominant signal wavelength of the geophysical signal; here, we use a localized spectral analysis of the geophysical signals, which we describe below in general terms and in greater detail in a companion paper [11]. The considered mass sources vary in time, with a seasonal and yearly variation for hydrology, or with a trend-like change-rate for lakes and glaciers. The time-frame of the geophysical quantity is relevant for the observations, since the error on the gravity signal recovered from the satellite mission reduces with a longer observation window, due to the increased number of observations and the increased reliability of the average and the reduced root mean square error of the observable signal. We define a signal to be detectable when part of the spectral energy of the signal is above the spectral error curve of the satellite observations. This definition relays the separation of a given signal from the multitude of signals that the satellite observes to a different analysis, which aims at a complete knowledge of the observed gravity signal in space and time. We think this is justified, because the question of whether a signal is in principle observable is different from the question of whether this signal can be separated from the other signals sensed by the satellite. Furthermore, the recent advances in the geodetic approach to calculating the gravity field includes the definition of the oceanic and atmospheric tidal and non-tidal variations, which greatly reduces the error caused by these sources [12; 13].
## 1 Introduction
### Paper Organization  
The rest of this paper is summarized as follows: Section 2 includes the related works and surveys of IEC, specifically, an overview of characteristics, challenges, open cases and applications and market drivers. Section 3 includes the main characteristics and benefits while Section 4 includes the main challenges. In Section 5, the potential use cases and applications are provided, whereas Section 6 includes the market drivers of IEC in 5G. Furthermore, Section 7 introduces IEC in 6G and the research challenges and future direction issues are presented. Finally, Section 8 concludes this paper.
# Data Access Based on a Guide Map of the Underwater Wireless Sensor Network
## 6 Experiments and Analysis  
### Experiment Setup  
Performance calculation and comparative analysis of DAGM and GHT are performed through simulated experiments in this section. In the simulated GHT experiments, where users query data, the query sentence is sent to all storage nodes through GHT routing in the network. The query result is notified and application data are compressed in a package that returns to the user along same routing. With regard to the experimental context where the network coverage is in an 80 km \(\times\) 80 km ocean area, the senor nodes are uniformly deployed. Underwater communication relies on acoustic communication, and the speed of sound velocity in the water is \(V\) = 1500 m/s, where it is assumed that in the transmission channel, energy consumption of transmission data is cubically proportional in relationship to the distance. Here, two scenarios and three states are set according to different situations on application data and network connectivity. In Scenario 1, the network has application data that meets the query sentence; in Scenario 2, the network does not have application data that meets the query sentence. The differences in sensor node parameter and network connectivity (the number of the network connectivity paths between any two nodes) have a heavy influence on data transmission routing and transmission delay. Therefore, this section sets the following three network states according to the differences in sensor node parameter and network connectivity:  
* The sensor node communication radius is \(r_{b}\) = 10 km, the number of deployed sensor nodes is \(n_{b}\) = 400, and average connectivity is \(k_{b}\) = 8.5.
* The sensor node communication radius is \(r_{b}\) = 20 km, the number of deployed sensor nodes is \(n_{b}\) = 100, and average connectivity is \(k_{b}\) = 3.5.
* The sensor node communication radius is \(r\) = 10 km, the number of deployed sensor nodes is \(n_{b}\) = 400, and average connectivity is \(k_{b}\) = 3.5.
# The Levenberg-Marquardt Method for Acousto-Electric Tomography on Different Conductivity Contrast
## 2 The Reconstruction Algorithm Based on Levenberg-Marquardt Method  
### The Inverse Problem and Forward Model  
A physical body imaged by EIT is modeled as a bounded Lipschitz domain \(\Omega\subset\mathbb{R}^{n}\) for \(n\geq 2\). The changes caused by the acoustic wave can be recorded with EIT measurements on boundary \(\partial\Omega\)[18; 19; 20]. The power density in \(\Omega\) is defined as  
\[\mathcal{E}(\sigma)=\sigma|\
abla u(\sigma)|^{2},\;\Omega\subset\mathbb{R}^{n}. \tag{1}\]  
where \(\sigma\) is the conductivity map in domain \(\Omega\). \(u(\sigma)\) is the electrical potential produced by applying either voltage or electric current on \(\partial\Omega\). Given noisy measurements \(\mathcal{E}^{\delta}(\sigma)\) of the true power density \(\mathcal{E}(\sigma)\), the problem is to reconstruct conductivity map \(\sigma\) via minimizing the following functional,  
\[\min_{\sigma}||\mathcal{E}^{\delta}(\sigma)-\mathcal{E}(\sigma)||_{L^{2}( \Omega)}. \tag{2}\]  
The power density \(\mathcal{E}(\sigma)\) can be reconstructed from the boundary measurements [2; 21]. The nonlinear relationship between \(\mathcal{E}(\sigma)\) and \(\sigma\) renders this problem nonlinear [22]. To develop the methods for reconstructing \(\sigma\) from \(\mathcal{E}(\sigma)\), the continuum model with Dirichlet condition is used here  
\[\
abla\cdot\sigma\
abla u =0,\;\text{in}\;\Omega \tag{3a}\] \[u =f,\;\text{on}\;\partial\Omega. \tag{3b}\]  
\(f\) is the boundary potential, \(f\in H^{1/2}(\Omega)\). The present work assumes \(\sigma\) is positive. With the assumption that measurements are carried out in the low frequency domain without any interior sources or chargesin \(\Omega\), Equation (3a) is obtained by simplifying time-harmonic Maxwell's equation with low-frequency approximation [17].
## 2 Research Method
### Non-Circular Spinning Based on the Hypocycloid Equation  
Using the hypocycloid equation for spinning non-circular parts, the principal axis of the workpiece and the principal axis of the roller rotate simultaneously, which means the two parallel principal axes rotate at a fixed ratio to ensure the roller trajectory follows a hypocycloid motion. The rollers rotating around the principal axis could be modeled as a fixed point on the moving circle of the hypocycloid, and the principal axis of the roller revolving around the workpiece was the fixed circle of the hypocycloid. Finally, the trajectory of the roller relative to the workpiece was the hypocycloid.  
At present, there are two methods of non-circular spinning based on hypocycloid theory. One method installs a single roller on the principal axis of the roller, and the regular polygon is processed by setting different relative rotation speeds between the two principal axes. The other method installs multiple rollers at symmetrical positions on the principal axis to process regular polygons.  
During the spinning of quadrilateral hollow parts, two rollers were installed at symmetrical positions on the principal axis of the roller, as illustrated in Figure 1. The trajectories of the two rollers created two mutually perpendicular ellipses, as shown in Figure 3. If the coordinates of the first roller are \((x_{1},y_{1})\), and the coordinates of the second roller are \((x_{2},y_{2})\), then the trajectory equation of the two rollers can be expressed as  
\[\left\{\begin{array}{rl}x_{1}=(r+e)\cos\theta\\ y_{1}=(r-e)\sin\theta\\ x_{2}=(r-e)\cos\theta\\ y_{2}=(r+e)\sin\theta\end{array}\right.\]  
Figure 2: Schematic drawing of a hypocycloid.  
During the process, the two rollers spun with multiple passes, and the principal axis of the roller was fed in the radial direction after every pass, as shown in Figure 3. The processing trajectories of the two rollers show how the workpiece was gradually transformed from a tube into a quadrilateral part via the continuous radial feed with each pass.  
This new method of quadrilateral non-circular spinning differs from previous quadrilateral non-circular spinning approaches, in which the radial feed was mainly driven by the motor, and the rotation speed of the workpiece was generally set to between 60 and 240 rpm to ensure synchronization between the workpiece rotation and radial feed. Conversely, the rotation rate of the workpiece could be set to 600 rpm using the newly proposed non-circular spinning process theory. Since synchronization between the workpiece rotation and the radial feed did not need to be considered, only the principal axis of the workpiece was synchronized with the principal axis of the roller. This condition was easier to achieve and, therefore, the accuracy of the radial feed of the roller could be assured, and the efficiency of the non-circular spinning process was greatly improved.