esa-sceva/satcom-chunk-collection huggingface dataset:
# Demonstration of Diode-Pumped Yb:LaF\({}_{3}\) and Tm,Ho:LaF\({}_{3}\) Lasers  
[PERSON]  
1 School of Physics Science and Engineering, Tongji University, Shanghai 200092, China; 2  
2 State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China 2  
2 State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China; 3  
high conversion efficiency. After decades of development, Yb-doped fluoride crystals, such as Yb:CaF\({}_{2}\), have been comprehensively reported [14; 15; 16; 17].  
In recent years, thulium (Tm) and holmium (Ho) active ions have been investigated because of their luminescence emissions near the 2 \(\upmu\)m region in lasers, giving them great application potential in human eye safeness and high atmospheric transmission [18; 19; 20; 21; 22; 23; 24]. Tm and Ho co-doped materials are promising candidates to directly obtain 2 \(\upmu\)m region lasers with a compact structure. The around 790 nm laser diode (LD) acts as a pumped source to excite Tm\({}^{3+}\) ions, then, according to the energy transfer between Tm\({}^{3+}\) ions and Ho\({}^{3+}\) ions, Ho\({}^{3+}\) ions ultimately produce 2 \(\upmu\)m laser radiation [25; 26]. Therefore, Tm,Ho co-doped materials could be operated as laser gain materials for the DPSSL system. Thus far, studies on Tm,Ho co-doped fluoride crystals have focused on Tm,Ho:YLF, Tm,Ho:KYF and Tm,Ho:LLF [8; 19; 20; 21; 27; 28; 29].  
In this work, we report two novel fluoride crystal materials: Yb:LaF\({}_{3}\) and Tm,Ho:LaF\({}_{3}\). Yb:LaF\({}_{3}\) and Tm,Ho:LaF\({}_{3}\) crystals are typical rare-earth-ion-doped fluoride crystals, so they possess the luminescent properties of rare-earth ions and the excellent host advantages of fluoride crystals. Moreover, La ions are of +3 valence, the same as Yb, Tm, and Ho ions; therefore, there is no charge imbalance in the process of ion doping. However, to date, Yb:LaF\({}_{3}\) crystals have not achieved laser output as solid-state laser gain materials, and Tm,Ho:LaF\({}_{3}\) crystals have not been reported [30].  
Yb:LaF\({}_{3}\) and Tm,Ho:LaF\({}_{3}\) crystals were prepared via the Bridgman growth method. Yb:LaF\({}_{3}\) crystals with a doping concentration of 1% had a maximum absorption coefficient of 0.25 cm\({}^{-1}\) at 973 nm. Matching the strongest absorption, Yb:LaF\({}_{3}\) continuous-wave (CW) lasers were demonstrated with a maximum average output power of 1.19 W. When the output mirror had a transmittance value of 5%, a Tm,Ho:LaF\({}_{3}\) CW laser was built and the maximum average output power was 416 mW. Employing an output mirror with a transmission value of 2%, the Tm,Ho:LaF\({}_{3}\) CW laser obtained a maximum average output power of 574 mW. The novel crystals, Yb:LaF\({}_{3}\) and Tm,Ho:LaF\({}_{3}\), were used as laser gain materials to demonstrate CW laser operations as DPSSLs.
## 6 Further Analysis of Designed Controller Robustness
### Case 1: Random Multi-Step Energy-Load Variation  
In this considered case, the source and load disturbances were divided according to the actual data to be presented in the next subsection into three levels: \"low\", \"medium\", and \"high\". According to the real data measurements, for the load disturbances, the \"low\" value was 0.32 p.u., the \"medium\" value was 0.525 p.u. and the \"high\" value was 0.73 p.u., respectively. The same levels for the wave energy corresponded to 0.015 p.u., 0.0825 p.u.,  
Figure 8: Frequency response through best PIDF/FOPID/2 DOF-PIDF controllers found (all with the JSO).  
and 0.15 p.u., while for the solar energy, the \"low\", \"medium\", and \"high\" levels were 0 p.u., 0.06 p.u., and 0.12 p.u., respectively. Thus, three profiles of multi-step variations were created for solar, wind, and load shown in Figure 9, which included all possible combinations (three sources and three levels = \(3^{3}\) = 27 possible combinations). It should be stated that this case cannot correspond to reality because the magnitude of changes observed within such a short time frame seems implausible to occur in reality. However, this case was tested in order to demonstrate the reliability of the JSO-tuned 2 DOF-PID controller in all possible cases of disturbance, even in the worst case when the load was at its maximum and the renewable sources could not contribute (i.e., \(t\) = 680-700 s).  
Figure 10 depicts the frequency response with the 2 DOF-PIDF controller for all the considered bio-inspired optimization algorithms. It can be concluded that the response frequency deviation range lied between [\(-\)0.2 0.2] Hz at most. By observing Figure 10, it can be seen that, at the instant where the maximum overshoot (\(t\) = 300 s) and maximum undershoot (\(t\) = 600 s) occurred, the load went from the maximum value to the minimum and from the minimum to the maximum, respectively. The remaining peaks of the frequency response appeared whenever the load changed between the three predefined levels.  
In the same figure, when the load presents its maximum value (0.73 p.u.) and the solar and wave sources do not contribute (0 p.u. and 0.015 p.u., respectively) at time \(t\) = 670-700 s, there is a negligible frequency deviation. Furthermore, when the load increased from its lowest value to its highest value \"instantaneously\" at \(t\) = 600 s, there was a maximum undershoot of 180 mHz. Nevertheless, this case is unrealistic as the loads and the contribution of renewable sources changed abruptly and with large variations. However, even in this scenario, the 2 DOF-PIDF controller demonstrated superior performance in managing extreme frequency fluctuations within the shipboard microgrid.  
Figure 9: Combination of energy profiles considered, for a 15 min period (**top** to **bottom**): ship energy demand (load variation), sea wave energy provided, and photovoltaic source energy provided.
# Threat Detection Model for WLAN of Simulated Data Using Deep Convolutional Neural Network
## 2 Materials and Methods
### Generating Data Frames for Training and Applying Channel Impairments  
The generated data includes the generation of packets holding MAC beacon frames, which is a kind of managing frames to identify a basic service set (BSS) produced by several 802.11 devices appropriate for baseband modeling. A platform called software-defined radio (SDR) was used according to Section 9 IEEE standard [38]. Beacon frames consist of; (1) a valid frame check sequence (FCS), (2) a beacon frame body, which carries data that requests to transmit, and (3) a MAC header, which contains frame information. The transmitter computes the FCS over the frame body and header. The receiver employs the FCS to ensure that the frame body and header are properly created.  
An experimental setup using USRP SDRs is conducted to acquire I/Q samples as shown in Figure 5. We use several different devices with USRP B210 family as transmitter devices, while a fixed USRP B210 is used for data collection at the receiver end.  
On each transmitter SDR, we send several physical layer frames according to IEEE 802.11 ac standards. These frames are compliant with standards and produced using the MATLAB WLAN Systems toolbox.  
Since we want to communicate any data streams, the data frames that are generated are random. The chosen SDR receives these protocol frames and streams them for over-the-air wireless transmission. For WiFi, the receiving SDR samples the inbound signals at a central frequency of 2.45 GHz and at a rate of 1.92 MS/s. Complex I/Q samples are gathered and divided into subsequences. We used a fixed subsequence length of 128 for our experimental study; further information is provided below. For each of the five SDRs, we gathered roughly 20 million samples in total. A general MAC frame diagram is shown in Figure 6[39].  
Generating MAC beacon frames includes three main stages; the control frames (Block Ack, Ack, CTS, and RTS), data frames (QoS Null, QoS data, Null, Data), and management frames (beacon). The flow work stages of generating MAC beacon frames are demonstrated in Figure 7.  
Figure 5: SDR-based Data collection.  
This stage consists of applying the channel impairments and RF defined before, generating an independent channel by resetting the channel object for each radio, processing the received frames using _RF_FingerprintingNonHT_Front_End_ function, performing L-LTF extraction from each WLAN transmitted frame, and splitting the L-LTF received signal data into test, validation and training parts. This process can be demonstrated in a flowchart shown in Figure 8.  
Figure 6: A general MAC frame diagram.  
Figure 7: Flow work stages of generating MAC beacon frames.
## 3 Model Construction and Review of Traditional A* Algorithms
### Environmental Model  
In existing research on UAV path planning, environmental modeling approaches include the raster method [30], visual map method, cell decomposition method, and high-dimensional reduction 3D environment modeling method. For the UAV monitoring of carbon dioxide emission path planning for heavy trucks in harbor areas, as studied in here, the raster method is adopted to depict environmental maps. The raster map has been widely applied in UAV flight path planning, offering advantages such as simplifying complex environmental information into easily accessible discrete cells. These cells visually represent obstacles and free areas in space. By selecting different raster sizes, map accuracy and computational complexity can be balanced, allowing path planning algorithms to find feasible paths within an acceptable timeframe. Thus, we employ the raster map to construct the simulation environment for subsequent experiments, which verify the algorithm's effectiveness. Figure 5 illustrates the 30 \(\times\) 30 raster environment used in our research, where the green point signifies the starting point, the red point the target point, the black square denotes the obstacle [31], and the white square indicates the navigable area.
## 2 Calculation Methods  
### Computational Details  
All first-principle calculations performed in this research were completed within the framework of the Density Functional Theory (DFT) as implemented in the ABINIT [34; 35] code. The Generalized Gradient Approximation (GGA) [36] in the Perdew-Burke-Ernzerhof (PBE) [36] form was selected for the Exchange Correlation (XC) functional. For all elements in our calculations, we used the Projected Augmented Wave (PAW) [37] pseudopotentials with projectors generated with the AtomPAW [38; 39; 40] code. GGA-PBE DFT calculations tend to contain the issue of underestimated bandgaps [41]. As a result, the underestimation may appear in the final result of our calculation, and may therefore suggest higher efficiency than the bandgaps had when tuning the bandgap of mixed perovskites. In light of this and in order to render accurate data, we use Equation (1) to adjust the final value.  
\[E_{gap}(corrected)=(E_{gap}(GGA-PBE)\times 1.358+0.125)\times 0.998+0.014 \tag{1}\]  
This equation is necessary in order to make comparison between actual material and theoretical calculation [42]. The displayed equation is adjusted to fit the difference between different types of perovskites. The corrected value gives similar result as the experimental values mentioned in Table 1.
# DAG Hierarchical Schedulability Analysis for Avionics Hypervisor in Multicore Processors
## 4 Schedulability Analysis
### Scheduling
#### 4.1.1 Concurrent Parent and Child Model
However, on the basis of the precedence constraints, it can be executed in parallel with \(\phi_{1}^{*}\) and \(\phi_{2}^{*}\) respectively. Using the CPCM, the DAG is converted to a series of capacity parents and children, \(O(|V|+|E|)\) is time complexity. The CPCM supplies complete information about possible delays of NC-joints on the CP. Every parent \(\phi_{i}^{*}\), joints in \(H(\phi_{i}^{*})\) can use a capacity of \(\mathit{length}(\phi_{i}^{*})\) on every of \((m-1)\) processors to run in parallel as lead, storing possible latency. Reanalyze in Figure 2a, the CP has three parents \(\phi_{1}^{*}=\left\{v_{1},v_{2}\right\}\), \(\phi_{2}^{*}=\left\{v_{6}\right\}\) and \(\phi_{3}^{*}=\left\{v_{9}\right\}\), as the delay from the NC-joint just appears at the header of the parents. For every parent, \(H(\phi_{1}^{*})=\left\{v_{3}\right\}\), \(H(\phi_{2}^{*})=\left\{v_{5},v_{7},v_{8}\right\}\) and \(H(\phi_{3}^{*})=\varnothing\). In short, whole jointsin \(H(\phi_{2}^{*})=\{v_{5},v_{7},v_{8}\}\) can start before \(\phi_{2}^{*}\) prolonging the execution of \(H(\phi_{1}^{*})\) and the start of \(\phi_{2}^{*}\). \(G(\phi_{1}^{*})=\{v_{5},v_{7},v_{8}\}\), \(G(\phi_{2}^{*})=G(\phi_{3}^{*})=\varnothing\). Parallel and disruptive workloads of the capacity parent are now formalized. \(h(\cdot)\) is the completion time of a parent \(\phi_{i}^{*}\) or a child joint \(v_{j}\), \(L_{i}=\mathit{length}(\phi_{i}^{*})\), \(\phi_{i}^{*}\) is the length and the total workload of \(\phi_{i}^{*}\) is \(C_{i}=\sum_{v_{k}\in H(\phi_{i}^{*})}\{C_{k}\}+\sum_{v_{k}\in G(\phi_{i}^{*})} \{C_{k}\}+L_{i}\), \(H(\phi_{i}^{*})\) and \(G(\phi_{i}^{*})\). The terms parallel and disruptive workload of a parent \(\phi_{i}^{*}\) is formally defined. \(\sum_{\phi_{i}^{*}\in\Theta}C_{i}\geq C\) as a child can be accounted for more than once it it can run concurrently with multiple parents. The parallel workload \(\alpha_{i}\) of \(\phi_{i}^{*}\) is the workload in \(C_{i}-L_{i}\) that can run starting at the time instant \(h(\phi_{i}^{*})\). The interfering workload of \(\phi_{i}^{*}\) is the workload in \(C_{i}-L_{i}\) that runs after the time instant \(h(\phi_{i}^{*})\). With a parent \(\phi_{i}^{*}\), its interfering workload is \(C_{i}-L_{i}-\alpha_{i}\). For parents \(\phi_{i}^{*}\) and \(\phi_{i+1}^{*}\), the workload in \(C_{i}\) that can prolong the start of \(\phi_{i+1}^{*}\) is \(C_{i}-L_{i}-\alpha_{i}\) at best. Based on the CPCM, the start of \(\phi_{i+1}^{*}\) depends on the finish of both \(\phi_{i}^{*}\) and \(H(\phi_{i}^{*})\), which is \(\max\{f(\phi_{i}^{*}),\max_{v_{j}\in H(\phi_{i}^{*})}h(v_{j})\}\). By Definition 1, \(\alpha_{i}\) will not cause any delay as it always finishes before \(h(\phi_{i}^{*})\), and hence, the Theorem follows. Note that, although \(G(\phi_{i}^{*})\) cannot delay directly, it can delay on nodes in \(H(\phi_{i}^{*})\), and in turn, causes an indirect delay to \(\phi_{i+1}^{*}\).
# Improved PEG-Based Construction of Analog Fountain Codes
## 2 Analog Fountain Codes and the PEG Algorithm
### The PEG Algorithm  
Short cycles on Tanner graphs may deteriorate the decoding performance of the BP. Thus, the PEG [13] maximizes the cycle length in the Tanner graph by progressively establishing edges between VNs and CNs in an edge-by-edge manner. VN degree is defined as the number of nonzero elements in each column of G.  
Suppose PEG is used to construct an \(n\times k\) matrix \(\mathbf{G}\) for AFC. For a given \(c_{j}\), where \(0\leq j<n\), we define its neighbor VNs within a depth \(l\) as \(N_{c_{j}}^{l}\), and the remaining VNs are denoted by \(\overline{N_{c_{j}}^{l}}\). If the subgraph from \(c_{j}\) is fully expanded in depth \(l\), two cases may happen. The cardinality of \(N_{c_{j}}^{l}\) may stop increasing but \(\left|N_{c_{j}}^{l}\right|<k\), or \(\overline{N_{c_{j}}^{l}}\
eq\emptyset\) but \(\overline{N_{c_{j}}^{l+1}}=\emptyset\). Let \((c_{j},b_{i})\) denote the edge connecting \(c_{j}\) and \(b_{i}\). At last, the newly established edge is \((c_{j},b_{i})\), where \(b_{i}\) is picked from the set \(\overline{N_{c_{j}}^{l}}\) with the lowest VN degree. Note that length-\(r\) cycle arises if \(\overline{N_{c_{j}}^{l+1}}=\emptyset\), where \(r=2(l+1)\).  
When PEG is used to construct generator matrices for AFC, both edge selection and weight coefficients allocation should be considered. In [10], if the edge \((c_{j},b_{i})\) is selected according to PEG, the weight coefficients are suggested to be allocated according to their appearance in the \(i\)-th column of \(\mathbf{G}\). Specifically, we calculate the times that each weight coefficient appears among the nonzero elements in the \(i\)-th column. The one with the lowest number of times should be allocated in order to balance the weight of columns in \(\mathbf{G}\).
# Cost-Effective Satellite Ground Stations in Real-World Development for Space Classrooms
###### Abstract  
This paper presents the development and outcomes of a cost-effective satellite ground station designed as a learning tool for satellite communication and wireless communication education. The study investigates accessible satellites and the methods for accessing them. The developed ground station has the capability to access satellites in the V, U, and L frequency bands, allowing it to receive a variety of satellite data. This includes full-disk meteorological images, high-resolution multispectral images, and scientific data from payloads of satellites in both low Earth orbit (LEO) and geostationary orbit (GEO). The ground station demonstrates capabilities similar to those of large organizations but at a significantly lower cost. This is achieved through a process of identifying educational requirements and optimizing the system for cost-efficiency. This paper presents the design demonstration, actual construction of the ground station, and results. Additionally, it compiles characteristics from real signal reception experiences from various satellites.  
satellite ground station; satellite communication; meteorological satellite; antenna; software-defined radio (SDR); GEO-KOMPSAT-2A (GK2A); Fengyun-2 (FY-2); Electro-L; NOAA POES; Imarsat Article
## 4 Discussion
### Future Application and Limitation of Temporo-Spatial Parameters in Polar Coordinates  
In this study, we adopted temporoospatial parameters in an extrinsic coordinate frame to analyze motor control characteristics for two planes and various circular tracking movement speeds in a 3D environment. However, the temporospatial parameters in this study did not allow us to analyze different biomechanical constraints (i.e., arm posture of the kinematic chain, torque of each joint) in an intrinsic coordinate frame for the two planes. In other words, the different biomechanical constraints in the two planes could impact the control of the hand position (i.e., temporospatial parameters in polar coordinates) in an extrinsic coordinate frame. In the future, we will analyze the different biomechanics in an intrinsic coordinate frame between circular tracking movement on the two planes by experimentally recording and analyzing the arm posture and related muscle activities during circular tracking tasks [34; 35; 36].  
The VR system used in this study allowed subjects to perform three degree-of-freedom visuomotor tracking movements in an immersive three-dimensional VR environment. In our future study, the proposed method and analysis parameters (i.e., temporoospatial parameters in polar coordinates) can be used for evaluating the seriousness of illness and the effectiveness of rehabilitation for patients with hemiplegic upper limbs. The method can also be applied to perception studies of spatial neglect patients [37].
## 5 Conclusions
#### Notations  
\begin{tabular}{l l} \(u\) & Velocity component of fluid in \(x\) direction \\ \(v\) & Velocity component of fluid in \(y\) direction \\ t & Flow time \\ \(F_{q}\) & Ratio of the volume of \(q\)-th phase fluid in the cell to the total cell volume \\ \(\varphi_{q}\) & Fluid parameter \\ \(F_{n}^{n}\) & Normal contact force at time \(n\) \\ \(K_{n}\) & Normal contact stiffness \\ \(C_{n}\) & Contact viscous coefficient \\ \(\delta_{ij}\) & Overlap value between the two disks \(i\) and \(j\) \\ \(V_{ij}\) & Relative velocity vector of the contact faces \\ \(\mathbf{n}\) & Normal unit vector of the contact cells \\ \(F_{t}^{n}\) & Tangential forces at time \(n\) \\ \(F_{t}^{n-1}\) & Tangential forces at time \(n-1\) \\ \(K_{t}\) & Tangential stiffness between particles \\ \(\Delta t\) & Time step \\ \(\mathbf{t}\) & Tangential unit vector between contact cells \\ \(\mu\) & Coefficient of sliding friction \\ \(C\) & Concentration \\ \(k\) & Vertical diffusion coefficient \\ \(K_{H}\) & Horizontal diffusion coefficient \\ \(P\) & Position of the marked substance micelle at time \(\Delta t\) \\ \(K\) & Normal coordinates \\ \(\Delta A\) & Number of cells in the computational domain \\ \(V_{i}\) & Volume occupied by the particles on the ocean surface in grid cell \\ \(\tau_{x}/f\) & Shear stresses of the wind in the \(x\) direction \\ \(\tau_{y}/f\) & Shear stresses of the wind in the \(y\) direction \\ \(D_{\mathbf{s}}\) & Diffusion coefficient of the oil film \\ \(f\) & Friction coefficient of the oil-water interface \\ \(g\) & Acceleration due to gravity \\ \(R_{h}\) & Physical-chemical kinetic terms \\ \(S_{0}\) & Initial position of the oil-film centroid \\ \(S\) & New position of the oil-film centroid after a time \(\Delta t\) \\ \(U_{L}\) & Velocity of oil-film drift \\ \(U_{f}\) & Velocity on water surface \\ \(U_{w}\) & Velocity of wind \\ \(a_{f}\) & Horizontal flow coefficient \\ \(a_{w}\) & Wind frag coefficient \\ \(x_{0}\),\(y_{0}\) & Initial centroid position \\ \(x\),\(y_{\sigma}\) & Centroid position after a time \(\Delta t\) \\ \(u\) & Current velocity in the \(x\) direction \\ \(v\) & Current velocity in the \(y\) direction \\ \(i_{w}\) & Correction factor \\ \(\theta\) & Wind angle \\ \(Mf\overset{\rightarrow}{k}\times\overset{\rightarrow}{U}\) & Coriolis force \\ \(A\overset{\rightarrow}{T}_{a}\) & Force of the wind above ice floe \\ \(A\overset{\rightarrow}{T}_{w}\) & Force of the current above ice floe \\ \(M\)_g-gradH_ & Effects of the ocean surface slope \\ \(\overset{\rightarrow}{F}\) & Non-linear ice internal force \\ \(H\) & Gravitational potential on the ocean surface \\ \(f\) & Coriolis force coefficient \\ \(\overset{\rightarrow}{k}\) & Unit vector perpendicular to the ocean surface \\ \(\overset{\rightarrow}{U}\) & Velocity of the [PERSON] floe \\ \(A\) & Ice density \\ \end{tabular}
###### Abstract  
To examine the effect of ionizing radiation on fluoride release from restorative dental materials, samples of Equia Forte HT, Fuji Triage, Fuji IX, Cention Forte, Activa Presto, Beautiful II, and Luminos (n = 10) were made in Teflon molds and divided into a control group and an experimental group. The experimental group was exposed to ionizing radiation for a total of 35 days (70 Gy, 2 Gy per day). The fluoride release was measured with a fluorine-selective electrode. The median recorded fluoride values were higher with Equia Forte HT, Fuji Triage, and Fuji IX compared to others during the entire period in both groups. With Activa Presto, a higher release of fluoride was recorded in the experimental group on the first day of irradiation, while a higher release was recorded in the control group, as well as with Luminos and Beautiful II. With Cention Forte, there was no significant difference in fluoride release between the experimental and control groups except on the sixth day. With Fuji Triage and Fuji IX, the release of fluoride was higher in the experimental group compared to the control group, while with Equia Forte HT, there was no difference between the groups. In conclusion, ionizing radiation has no major effect on fluoride release in all the tested materials.  
ionizing radiation; dental materials; fluoride release +
Footnote †: journal: Applied sciences