esa-sceva/satcom-chunk-collection huggingface dataset:
_Applied_  
_sciences_  
_Article_  
**Damage Analyses of Replaceable Links in**  
**Eccentrically Braced Frame (EBF) Subject to**  
**Cyclic Loading**  
**[PERSON] \({}^{1,2,\bullet}\), [PERSON] \({}^{1,\bullet}\) and [PERSON] \({}^{3}\)(\({}^{\copyright\)}\)**  
\({}^{1}\) School of Civil Engineering, Lanzhou University of Technology, Lanzhou 730050, China  
\({}^{2}\) Western Engineering Research Center of Disaster Mitigation in Civil Engineering of Ministry of Education, Lanzhou University of Technology, Lanzhou 730050, China  
\({}^{3}\) College of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China; [EMAIL_ADDRESS]  
\({}^{\bullet}\) Correspondence: [EMAIL_ADDRESS] (Z.Y.); [EMAIL_ADDRESS] (D.F.)  
Received: 14 December 2018; Accepted: 13 January 2019; Published: 18 January 2019  
**Featured Application: The main purpose of this study is to present a shear device consisting of a central \"fuse\" link to examine the seismic behavior and to analyze the damage modes of replaceable links in steel eccentrically braced frames. It can be applied in the seismic design requirements for main steel building seismic force-resisting systems, as driven by new developments and changes in earthquake engineering practice.**  
**Abstract: In the current design of steel eccentrically braced frames (EBFs), the yielding link is coupled with the floor beam. This causes the design of cross-sectional dimensions of links to be enlarged, resulting in over-designed structures and foundations, and increasing the cost of the overall structure. In addition, the beams are forecast to sustain severe damage through repeated inelastic deformations under design-level earthquakes, and thus the structure may require extensive repair or need to be replaced. To improve upon these drawbacks, a shear device with replaceable links based on EBFs was designed. The hysteresis curve, the stress distribution, and the deformation of the specimen were obtained by cyclic loading tests of the eight replaceable links. The energy dissipation behavior, the bearing capacity, the failure modes, and the plastic rotation angle of those specimens were analyzed. The results indicated clearly that the links in this shear device had inelastic deformation concentrated in the link showing very stable hysteresis behavior, and damaged links were replaced easily as end-plate connections were adopted. The energy dissipation capacity and the plastic rotation angle of the specimens were mainly dependent on the arrangement of stiffener, length ratio, and welding access holes. Experimental studies performed in this research and the related damage analyses reveal that cracks are the major causes of damage to the EBF and there is a lack of research on real-time monitoring of the onset and development of these cracks in EBF structures. As a future work, this paper proposes a piezoceramic patch transducer-based active sensing approach to monitor the crack onset and development of the EBF when subjected to dynamic loadings.**  
**Keywords: replaceable links; eccentrically braced frame; welding access hole; length ratio; energy dissipation capacity; damage mode analyses**
## 3 The Proposed Multi-Scale Demodulation Method
### Adaptive Signal Decomposition Based on EMD  
The EMD method was first proposed by [PERSON] et al. in 1998 [24]. It can decompose a signal into some mono-components according to the local characteristic time scales of the signal--so-called intrinsic mode functions (IMFs)--to represent the natural oscillatory mode embedded in the signal and work as the basis functions; the method can be applied to nonlinear and non-stationary processes. The detail procedure of EMD is given as follows.  
**Step 1**: Calculation of the envelope.  
Identify all the local extrema in the signal. Connect all the local maxima by a cubic spline line as the upper envelope. Repeat the procedure for the local minima to produce the lower envelope. The schematic plot is as shown in Figure 5.  
**Step 2**: Removal of the envelope mean.  
Calculate the mean of the upper and lower envelopes. Remove these from the signal \(x(t)\).  
\[y_{1}(t)=x(t)-\mu_{1} \tag{2}\]  
**Step 3**: Extraction of the IMF.  
To judge whether \(y_{1}(t)\) is an IMF, if \(y_{1}(t)\) satisfies the requirements of an IMF, set the first IMF as \(c_{1}(t)=y_{1}(t)\). Otherwise, let \(y_{1}(t)\) be the raw signal, and repeat step 1 to step 2. It is noted that an IMF is defined as a function that satisfies the following requirements: (1) in the whole data set, the number of extrema and the number of zero-crossings must either be equal or differ at most by one; (2) at any  
Figure 5: Schematic plot of the calculation of upper and lower envelopes.  
point, the mean value of the envelope defined by the local maxima and the envelope defined by the local minima is zero.  
**Step 4**: Decomposition. Separate the IMF \(c_{1}(t)\) from the raw signal \(x(t)\).  
\[r_{1}(t)=x(t)-c_{1}(t) \tag{3}\]  
where the residual signal \(r_{1}(t)\) is treated as the raw signal \(x(t)\) = \(r_{1}(t)\) and subjected to the same sifting process from step 1 to step 3; then, the second IMF \(c_{2}(t)\) can be obtained. After n repeats, the sifting process finally stops when the residue \(r_{n}(t)\) becomes a monotonic function from which no more IMFs can be extracted.  
\[x(t)=\sum_{j=1}^{n}c_{j}(t)+r_{n}(t) \tag{4}\]  
Thus, a decomposition of the signal into n-empirical modes is achieved. The IMF from \(c_{1}(t)\) to \(c_{n}(t)\) carries oscillating components of the raw signal from high frequency to low frequency.
# Deployment Protection for Interference of 5G Base Stations with Aeronautical Radio Altimeters
## 2 Methodology
### Deployment Protection Methods
#### 2.3.1 Prohibited Zone  
The prohibited zone is obtained by following the procedure shown in Algorithm 1. First, the aircraft is located at point \((0,0,H)\), where \(H\) represents the altitude AGL, with this paper considering altitudes of 100 ft, 1000 ft, and 2000 ft. Second, within a three-dimensional space of dimensions \((X,Y,H)\), the antenna gain (\(G_{bf}\)) of the base station at a coordinates \((x,y,h)\) is computed. Due to the use of beamforming technology, \(G_{bf}\) is not only dependent on the coordinates \((x,y,h)\) but also on the vertical scan angle (\(\theta\)). Additionally, the gain (\(G_{a}\)) of the radio altimeter antenna in this direction is related to the coordinates \((x,y,h)\) and the pitch\(\backslash\)rollangles of the aircraft \(\alpha\backslash\beta\). When considering path loss (\(P_{loss}\)), a random function is employed to ensure that the probabilities of line-of-sight loss (\(P_{LOS}\)) and non-line-of-sight loss (\(P_{NLOS}\)) occurring are both 50%. Third, the interference with the aircraft \((I(x,y,h))\) generated by the base station at the coordinates \((x,y,h)\) is calculated. When \(I(x,y,h)\) equals the interference threshold value (\(Th\)), the coordinates of this point are recorded as \(z_{i}\). All points are traversed to find all \(z_{i}\) values. Finally, all points are connected to form the outline of the entire prohibited zone. Within the outline, a base station may cause interference with the aircraft. Outside the outline, interference is below the interference threshold.  
Figure 8: Worst-case landing scenario (WCLS).  
The interference threshold varies at different altitudes AGL. For example, at 2000 ft, the interference threshold can be as low as \(-69\) dBm.The attenuation caused by increasing altitude cannot compensate for the decrease in the interference threshold, resulting in a larger prohibited zone. The pitch\(\backslash\)roll angle of the aircraft also causes a change in the gain of the altimeter antenna. It provides a larger gain for the interfering signal, which can make the prohibited zone larger.  
In the context of aircraft operation, the prohibited zones extend not only to the horizontal plane but also to the vertical plane. The horizontal prohibited zones imply that base stations located within the horizontal vicinity of the runway and around the aircraft's ground projection must be prohibited. The vertical prohibited zones refer to the fact that base stations situated atop tall buildings, mountains, and undulating terrain must also be prohibited.
# Joint Radar and Communications Waveform Design Based on Complementary Sequence Sets
## 2 JRC-CWG Model
### Receive Signal Model at the Radar Receiver  
The receive signal model at the radar receiver is shown in Figure 3a. For the sake of simplicity, we only consider returns from one point target in this paper. It can be easily extended to more general scenarios. Furthermore, it is reasonable to assume that the velocity of the vehicles is low. Hence, the Doppler shift of the returns in one PRI can be regarded as a constant value. Thus, the sampled return from a point target at the radar receiver of the JRC system can be represented as  
\[\mathbf{s}_{g,m}^{r}=\delta_{g}pe^{2\pi f_{d}T(m-1)}\mathbf{s}_{g,m}+\mathbf{ n}_{g,m} \tag{2}\]  
Figure 1: Intelligent transportation system.  
Figure 2: The transmit waveform model of the JRC-CWGs.  
where \(\delta_{g}\) is the complex scattering coefficient including the path loss and RCS of the target. According to [40,41], the RCS of a target can be described using the Swerling I model, i.e., the RCS of the target does not fluctuate in each CPI, and it will only fluctuate during different CPIs. Further to this, the path loss can be regarded as a constant value in each CPI. Thus, we assume that \(\delta_{g}\) is a constant value in the \(g\)-th CPI. \(\rho=e^{2\pi f_{d}T[(g-1)M]}\), and \(f_{d}=2v/\lambda\) denotes the Doppler frequency, where \(v\) is the relative radial velocity between the JRC system and the target, and \(\lambda\) is the wavelength of the transmit waveforms. \(\mathbf{n}_{g,m}\in\mathbb{C}^{N\times 1}\) is the vector of complex Gaussian white noise.  
The signal processing procedure at the radar receiver is shown in Figure 3b. \(\mathbf{h}_{g,m}^{MF}\) denotes the matched filter of \(\mathbf{s}_{g,m}\). As depicted in Figure 3b, the matched filter output of the \(g\)-th JRC-CWG returns are coherently accumulated, which can be denoted as  
\[\mathbf{y}_{g}^{r}=\delta_{g}\rho\sum_{m=1}^{M}e^{2\pi f_{d}T(m-1)}\mathbf{r}_ {g,m}+\sum_{m=1}^{M}\mathbf{n}_{g,m}^{{}^{\prime}} \tag{3}\]  
where \(\mathbf{n}_{g,m}^{{}^{\prime}}\in\mathbb{C}^{K\times 1}\)\((K=2N-1)\) is the matched filter output of \(\mathbf{n}_{g,m}\), which is still a Gaussian white noise vector. \(\mathbf{r}_{g,m}=\left[r_{g,m}(1-N),\ldots,r_{g,m}(-1),r_{g,m}(0),r_{g,m}(1), \ldots,r_{g,m}(N-1)\right]^{T}\) denotes the auto correlation function of \(\mathbf{s}_{g,m}\), where  
\[r_{g,m}(n)=\mathbf{s}_{g,m}^{H}\mathbf{U}_{n}\mathbf{s}_{g,m},\ \ \text{for}\ n=0,1,\ldots,N-1 \tag{4}\]  
and \(r_{g,m}(n)=r_{g,m}^{*}(-n)\), for \(n=1-N,2-N,\ldots,-1\). \(\mathbf{U}_{n}\) is expressed as  
\[\mathbf{U}_{n}=\begin{bmatrix}\mathbf{0}_{n\times(N-n)}&\mathbf{I}_{N-n}\\ \mathbf{0}_{(N-n)\times(N-n)}&\mathbf{0}_{(N-n)\times n}\end{bmatrix},\ \ \ n=0,1,\ldots,N-1 \tag{5}\]
## 4 Discussion of the Fault-Diagnosis Results  
In this section, the proposed MSFFCNN method is compared with conventional 1 DCNN, CNN with wide first-layer kernels (WDCNN) [27], and multi-scale CNN(MSCNN) [18]. The WDCNN uses the wide kernels in the first convolutional layer to suppress high-frequency noise, but the multi-scale structure is not deployed; the MSCNN uses multi-scale transformation to combine the captured multi-scale features without taking into account differences in the importance of different branches. Therefore, comparison with the above algorithms can effectively reflect the superiority of multi-scale structure and the proposed attention mechanism-based feature fusion.
## 7 Conclusions and Outlook  
An ultraprecise demonstration optical bench was constructed and tested for the Taiji pathfinder mission. With the precise positioning of the equipment, the angular deviation from the theoretical beam in the two end PDs of the interferometer were found to be less than 42 \(\upmu\)rad and 45 \(\upmu\)rad, and their deviation in position were 9 \(\upmu\)m and 10 \(\upmu\)m, respectively. Compared with our previous results, the sensitivity of this optical bench reached 6 pm/\(\surd\)Hz in the frequency band from 0.03 Hz to 1 Hz, thus representing a significant improvement. This was because the noise from frequency jitter  
Figure 6: Experimental results from the interferometer tests. The pathlength noise budget of the Taiji pathfinder optical bench (20 pm/\(\surd\)Hz) is similar to that of Lisa pathfinder [21] (18 pm/\(\surd\)Hz) in the frequency band from 0.03 Hz to 1 Hz.  
decreased considerably as a result of the precision positioning technology and the use of better optical bonding. The frequency jitter in the laser beam has therefore been largely suppressed in this optical bench. Although the demonstration system has been constructed and tested, the optical bench of the Taiji pathfinder is much more complex. Moreover, its mechanical and thermal reliability, which must satisfy environmental simulation tests of the Taiji pathfinder space flight, remains to be verified.  
Conceptualization, Z.L. and H.L.; methodology, Y.Z.; writing--original draft preparation, Y.L.; writing--review and editing, H.L. and, G.J.; funding acquisition, Z.W. and, W.S.  
This research was funded by the Strategic Priority Research Program of the Chinese Academy of Science (XDB23030000).  
The authors declare no conflict of interest.
# Performance Testing and Evaluation of Drum-Type Stem-Separation Device for Pepper Harvester
###### Abstract
[36] examined a drum-type threshing method that used a porous rotating drum to separate leaves from sorghum and parsley stems, and its SSE and DR were 90% and 10%, respectively. [PERSON] et al. [37] comparatively analyzed the drum type, rotational speed, and sunflower supply for sorting sunflowers. The optimal sorting drum was found to be the Rasp bar drum, and when the rotation speed was 700 rpm and the supply was 3000 kg/h, the SSE, DR, and loss were 99%, 1.39%, and 0.36%, respectively. To confirm the efficiency of a tractor-attached small tree-cutting chipper, the fuel consumption rate and productivity were compared for the drum and disk types [38]. As a result of the test, the drum-type chipper reduced fuel consumption by 19% and improved productivity by 8% compared to the disk-type chipper. A cassava harvester for stem removal was developed by [PERSON] et al. [39]. This machine installed a blade on the outside of the drum to find the optimal angle and thickness of the blade. The best result was obtained at a shear angle of 20\({}^{\circ}\), an approach angle of 30\({}^{\circ}\), and a thickness of 6 mm. [PERSON] [40] developed a device for separating peppers from stems by depositing harvested pepper stems into a drum-type threshing machine. Pepper SSE and DR were 82.7% and 4.4%, respectively, and the smaller the pepper, the lower the pepper SSE and DR. [PERSON] et al. [25] manufactured and tested a sorting device using a card cleaner and a cylindrical coil drum, and 60-75% of the debris was removed as a result, but the PTR was about 10%, which means additional work was needed to separate stems from peppers. [PERSON] et al. [41] attempted to determine the optimal drum rotation speed, the space between drums, and the drum rotation speed ratio for three rotating drums with steel-bar teeth. They found that the optimal conditions were a drum rotation speed of 70 rpm, a 5 mm space between drums, and a drum rotation speed ratio of 7:3:5, and the pepper SSE and DR were 60% and 15%, respectively. The method suggested in the current reference has low pepper SSE and high DR, so it was necessary to develop a drum-type pepper stem-separation device to improve SSE and DR. The purpose of this study was to design and manufacture a pepper-stem-separation device for a pepper harvester, and to evaluate its performance. The detailed objectives were as follows. To design and manufacture three-shaft and four-shaft drum stem-separation devices. To find the optimal drum rotation speed. To conduct a comparative performance test and evaluation of the three-shaft and four-shaft drum stem-separation devices.
## 4 Experiments
### Experimental Design
#### 4.2.1 Scene Graph Generation and Graph Embedding  
Mask R-CNN was used to perform object detection and semantic segmentation on the input satellite and street view images, generating scene graphs containing urban infrastructure [16]. These scene graphs were saved as structured data with nodes and edges. GraphSAGE and Node2 Vec were applied to convert scene graph nodes into low-dimensional vectors, preserving graph topology and spatial relationships.
## 3 Model of Image Motion
### Analysis of In-Orbit Disturbances
#### 3.2.1 Disturbances of Spacecraft  
A spacecraft in space is subject to various sources of disturbances, including but not limited to the following:  
1. Attitude control system: The operation of the attitude control system may introduce internal feedback disturbances, such as vibrations or noise in control signals. These disturbances can negatively impact the stability of the spacecraft's attitude.
2. Solar radiation pressure: Solar radiation exerts pressure on the spacecraft's surface, thus generating small forces that can induce attitude changes.
3. Gyroscope drift: Gyroscopes on the spacecraft may experience drift, thus leading to errors in attitude measurement and affecting the precision of the stable platform.  
These dynamic disturbances can influence the spacecraft's attitude, thereby impacting the accuracy of camera image motion compensation and ultimately affecting the image quality. To mitigate these disturbances, the corresponding compensation angles are calculated based on the real-time monitoring of satellite attitude parameters in the IMC model.
## 3 Results and Discussion
### False Positive Rate Studies  
False positive rates (FPR) were determined in replicates under the same conditions as the TPR studies, but in the absence of explosives. These measurements were collected in the laboratory (relatively low clutter) as well as an outside loading dock area (high particle clutter) in order to simulate real-world scenarios and observe typical backgrounds from cluttered shipping environments. A total of 10 replicates measurements were collected for each defined parameter. Similarly, the FPR values were calculated based on the fraction of the containers that did not contain explosives but resulted in a maximum signal (in Height, mV).  
From the 10 replicates, the portable IMS system resulted in no false positives. Since the alarm threshold was decreased for the sensitive detector, the benchtop IMS resulted with a FPR of 0.06. By increasing the minimum alarm threshold of the analytes of interest will still result with a TPR of 1.0 (\(>\)800 d.u.) and the FPR can be decreased to 0.  
FPR studies were also performed in a local commercial shipping facility in which several different containers were sampled as well as the headspace of the open area with only the portable IMS used in this part of the study. One-min dynamic sampling with IMS detection was performed in open areas as well as inside LD3 containers. Plasmagrams of the negative mode for the portable IMS shows a signal (\(\mathrm{t_{d}}=8.6\) ms) reflecting the presence of background volatiles in the headspace of the LD3 containers (Figure 3), however, none of the signals obtained from the background interfered with the analytes of interest. Moreover, from a total of 32 background samples that were sampled by PSPME-IMS in this highly cluttered environment, none caused a false positive alarm.
## 2 Mechanical Analysis Model for TSWs
### Determining the Number of Convergent Series Terms in the Mechanical Model  
The calculation parameters from the previous section are used, with all four edges of the TSWs under fixed and supported conditions. The number of graded terms for the calculation is set to 5, 10, 20, 30, 40, 50, 60, 70, and 80, respectively.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameters** & **Value** & **Units** \\ \hline Slope length (\(L\)) & 50 & m \\ Slope width (\(B\)) & 4 & m \\ Slope height (\(h\)) & 50 & m \\ Sidewall thickness (\(W_{b}\)) & 3 & m \\ Inter-chamber pillar width (\(a\)) & 4 & m \\ In-plane force in the y-direction (\(N_{y}\)) & 47.2 & MN\(\cdot\)m\({}^{-1}\) \\ In-plane force in the z-direction (\(N_{z}\)) & 78.8 & MN\(\cdot\)m\({}^{-1}\) \\ maximum value of lateral load (\(q_{0}\)) & 22.1 & MPa \\ lateral load per unit (\(k\)) & 0.044 & MPa\(\cdot\)m\({}^{-1}\) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Relevant parameters of the mine.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Rock Type** & **Orebody** & **Surrounding Rock** & **Units** \\ \hline Density & 2800 & 2500 & kg\(\cdot\)m\({}^{-3}\) \\ Elastic modulus & 32.5 & 20.0 & GPa \\ Cohesion & 5.2 & 4.9 & MPa \\ Internal friction angle & 50.0 & 36.0 & \({}^{\circ}\) \\ Tensile strength & 5.0 & 4.6 & MPa \\ Poisson ratio & 0.26 & 0.3 & N/A \\ \hline \hline \end{tabular}
\end{table}
Table 2: Physical and mechanical parameters of the rocks.  
According to Theory of Plates and Shells [23], the deflection of the thin plate is \(w=w_{mn}\frac{qL^{4}}{D}\) and its bending moments is \(M=M_{mm}qL^{2}\). By analyzing the changes in dimensionless quantities such as deflection coefficient \(\frac{D\cdot w(L/2,h/2)}{qL^{4}}\) at the center of the thin plate, the bending moment coefficient \(\frac{M_{y}(L/2,h/2)}{qL^{2}}\) in the y-direction at the center of the thin plate, the bending moment and coefficient \(\frac{M_{y}(0,h/2)}{qL^{2}}\) in the y-direction at the left midpoint of the thin plate, the number of convergent level terms of the mechanical model can be determined. The calculation results are shown in Table 3.  
As seen in the calculation results in Table 3, once the number of gradation terms reaches 20, the first three significant figures of the deflection coefficient at the center of the thin plate remain unchanged. After 40 terms, the first four significant figures of the deflection coefficient at the center of the thin plate stabilize, as do the first three significant figures of the y-direction moment coefficient at the center of the thin plate. Additionally, the first four significant figures of the y-direction moment coefficient at the left edge of the thin plate remain consistent. Thus, it can be concluded that with 40 gradation terms, convergence has been achieved, and subsequent calculations in this paper will use the results based on 40 gradation terms.