esa-sceva/satcom-chunk-collection huggingface dataset:
# Design of True Time Delay Millimeter Wave Beamformers for 5G Multibeam Phased Arrays
## 2 Beamforming Networks Design
### Rotman Lens Architecture
Following the principles of electromagnetic theory, the attenuation constant for the case of a TEM propagating mode in the parallel plate region when material losses are introduced is given by [48]:  
\[a_{d}=\frac{ktan\delta}{2} \tag{5}\]  
where \(k=\omega\sqrt{\epsilon\mu}\) stands for the wavenumber. Considering the desired frequency of operation and keeping in mind that the mode attenuates at a rate of \(e^{-a_{d}x}\) in the parallel plate region, we can evaluate the distance the wave has to cover to attenuate \(1/e\) in respect to its initial value. Based on this initial estimation the Rotman lens' absorbing area is initially designed and then in turn is optimized using an EM simulator. In our proposed design, following this procedure and after the necessary optimization, the length of the structure increases almost 6% with respect to the dummy-ports-based design, ensuring sufficient absorption of the incident waves in the side walls. Figure 11 presents how the dummy-port based design has been modified when absorbers are introduced in the side walls. Figure 10: Proposed Rotman lens architecture with three inputs (red), three outputs (green), and four dummy (D) ports (blue) in the side walls. The scale is 10:3.06 mm. This approach is proven to yield an almost perfect absorber, eliminating reflections along with their deleterious effects on the input matching and output phase fluctuations. The challenge here is to invent practical ways for the implementation of the assumed \"conductive doping\". A simple structure with only three input and three output ports is considered herein as a proof of concept, and it is proven to work very well.
# Experimental Simulation of Thunderstorm Profiles in an Atmospheric Boundary Layer Wind Tunnel
## 2 Literature Review
### Mean Wind Velocity
The effects of nonlinear growth of boundary layer thickness were also considered by the authors. They proposed the following expression:  
\[\overline{U}(z)=1.17\cdot\overline{U}_{m}\Bigg{[}\bigg{(}\frac{z}{z_{m}} \bigg{)}^{b_{2}-1}e^{b_{1}(\frac{z}{2m})b_{2}}\Bigg{]} \tag{5}\]  
where \(z_{m}=0.025D\), \(b_{1}=-0.16\) and \(b_{2}=\frac{1}{1+c_{1}}=1.19\). Figure 1 shows a comparison of the mean wind speed profiles \(\overline{U}\) obtained by the analytical models presented, normalized with respect to \(\overline{U}_{m}\) (Figure 1a) and \(\overline{U}_{ref}\) (Figure 1b), which represents the velocity at a reference height \(z_{ref}=10\) m, as functions of the height normalized with respect to \(z_{m}\) and \(z_{ref}\), respectively. [PERSON] et al. [39] observed that the vertical profile from the Vicroy model shows a remarkable difference with radar observations by [PERSON] [5], and with the experimental and numerical simulation results for downburst wind by [PERSON] et al. [6], [PERSON] and [PERSON] [40], [PERSON] and [PERSON] [37]. The agreement between Wood and Kwok model and the available full-scale data is overall significantly better than that of the Vicroy model. [PERSON] and [PERSON] [31] suggested the use of Vicroy model when the maximum radial velocity is located near the ground, and of Wood and Kwok model for maximum velocity at higher elevations.
## 3 Results and Discussion  
Considering several variables such as solar activity, \(\rho_{a}\), and associated anomalies, the results of this study provide visual information for interpreting in a simpler and more complete way. Figure 5 shows the space-time changes of the \(\rho_{a}\) for the USME station during the time interval when the Mesetas earthquake occurred (Mw6.0, Lon = 74.184\({}^{\circ}\) W, Lat = 3.462\({}^{\circ}\) N, H = 13 km-depth, 24 December 2019, UTC 19:03:55) and its associated aftershocks.  
\begin{table}
\begin{tabular}{c c c} \hline
**Period \(T\) (s)** & **Depths \(H\) (km)** & **Apparent Resistivity \(\rho_{a}\) (\(\Omega\)-m)** \\ \hline \(T\lesssim 2\) & \(0.2\,H\lesssim 3\) & \(10^{0}\lesssim\rho\lesssim 10^{1}\) \\ \(2\lesssim T\lesssim 15\) & \(3\lesssim H\lesssim 30\) & \(\rho\)\(\sim\)\(10^{1}\) \\ \(15\lesssim T\) & \(30\lesssim H\lesssim 80\) & \(10^{2}\lesssim\rho\lesssim 10^{3}\) \\ \hline \end{tabular} _Associated anomalies:_ There is a clear anomaly presented 11–16 h before 24 January (Table 3):  
\end{table}
Table 2: Variations of the \(\rho_{a}\) depending on the depth \(H\).  
Figure 6: Comparison between three apparent resistivity curves, each corresponding to a different hour interval of December 24 (UTC). The red curve represents the time when the anomaly is observed.
## 4 Controller Design
### Analysis of Model Uncertainty  
Although the model of helicopter is built, there exists errors in the model parameters. It has been proven that the ESO has significant robustness to the uncertainties of control input coefficients [40], which refer to \(R_{12}\) and \(R_{3}\) in this article. Therefore, only the inertia matrix \(J\) is necessary to be taken into account in this analysis.  
Define \(J\) as the unknown inertia matrix with real parameters. Additionally, \(\hat{J}\) is defined as the one with uncertainties. Based on the theory presented in [40], the estimation results will be changed to (19) with the uncertain inertia matrix.  
\[\left\{\begin{array}{l}\hat{f}=f-N\\ N=J^{-1}(\omega\times J\omega)-\hat{J}^{-1}(\omega\times\hat{J}\omega)\end{array}\right. \tag{19}\]  
The new pseudo-input of \(\overline{Q}_{c}\) will be obtained by subtracting an additional item \(N\) in (20).  
\[\widehat{\overline{Q}}_{c}=\overline{Q}_{c}-N \tag{20}\]When the new \(\overline{Q}_{c}\) and new \(f\) replace the old ones, new \(\theta^{*}\) will be obtained, and it is equal to the one derived without model uncertainty.  
\[\hat{\theta}=\theta^{*} \tag{21}\]  
Even with the parameter uncertainties of inertia matrix, the actual control input is the same as the nominal one obtained above. Therefore, the system is robust to model uncertainties theoretically.
## 4 Discussion  
This study evaluated whether strength training would be as effective in improving anaerobic capacity, aerobic power and endurance as aerobic interval training. It was hypothesized that strength training could be as effective in improving physical fitness as traditional aerobic interval training. The data obtained partially support the hypothesis. Strength training showed effectiveness in improving anaerobic capacity, and increases in PP (+5.59%) and MP (+3.90%) were observed. ST training, as well as AIT, proved effective in improving maximal oxygen uptake (+9.15% and +5.58%, respectively). It was shown that in all training groups, there was a significant increase in absolute VO2 max; the effect size in the ST group was (\(p\) < 0.001, ES = 0.50), and in the AIT group it was (\(p\) = 0.02, ES = 0.55). An increase in VO2 max of 5-9% as a result of AIT and ST for healthy people is practically imperceptible. This does not mean that a healthy, untrained population should not engage in such training. Any physical activity, despite the lack of noticeable training effects, is recommended and can prevent disease and promote good health. However, among athletes, such an increase can be decisive in winning and therefore may be important from a competitive point of view. In addition, our data can be helpful in modifying and optimizing training plans to maximize training effects. In people with low aerobic capacity (e.g., VO2 max: 15-20 mL/kg/min), such an increase can be very noticeable and determine independent mobility. Our data may be particularly important for people whose physical capacity limits their mobility and ability to walk or ride a bike, but allows them to perform strength training. In addition, the two training methods resulted in an increase in the maximal power obtained in the graded test (+8.08% (ST) and 4.41% (AIT)). The magnitude of the recorded effect was moderate in both groups. The results indicate that the applied strength training was at least as effective in improving the indices measured in the graded test as interval aerobic training. However, the applied strength training only
# Using Deep Learning for Collecting Data about Museum Visitor Behavior
## 2 State of the Art
### Indoor Localization Technologies
This sensor is able to provide information relating to the contour of surrounding objects. When combined with inertial sensors, LIDAR-based tracking systems can provide accurate results [28]. In order to properly work, the LIDAR-based tracking system needs at least one sensor in each room. Because of that, this particular technology would be extremely expensive for large museums. * Acoustic Signal. This technology can localize the user by capturing acoustic signals emitted from sound sources using a microphone sensor [29]. The acoustic signal localization is accurate only when audible band acoustic signals (i.e., <20 kHz) are used. For these signals, sufficiently low transmission power is required not to cause unwanted noise. This aspect, coupled with the need for additional infrastructure, results in that localization based on acoustic signals is not widely used. * Ultrasound. This technology allows us to compute the distance between a transmitter and a receiver by measuring the time of flight of ultrasonic signals (i.e., >20 kHz) [30]. Indoor localization based on ultrasound is very accurate. However, the measurement process can be heavily influenced by significant changes in temperature and humidity, as well as by ambient noise. Hence, the solutions above are inaccurate, expensive, or very complex to implement. We, therefore, focus on computer vision, which can represent a non-intrusive solution for the user already accustomed to security cameras.
## 3 Results and Discussion
### Effective Boundary Slip
#### 3.3.2 Superoleophobic Surfaces  
* _Hydrodynamic forces._ The plots of measured hydrodynamic forces \(F_{hydro}\) between the colloidal AFM probe and the superoleophobic surfaces immersed in hexadecane and ethylene glycol, as a function of separation distance \(D\), are shown in Figure 9. In order to obtain slip length, the \(V/F_{hydro}\) applied on the AFM probe is used for superoleophilic surfaces immersed in hexadecane and ethylene glycol as a function of separation distance. In the case of superoleophobic surfaces, it can be noted that the plots of \(V/F_{hydro}\) shift to the left with increasing \(Rsm\) from samples \(a1\) to \(a5\). The results are similar to those of superoleophilic surfaces. This means that the interception of \(V/F_{hydro}\) on the axis of separation distance shifts to the left from \(b1\) to \(b5\) and leads to increased slip length. The change of hydrodynamic forces \(F_{hydro}\) can be expressed by the varying \(R_{q}\) roughness of surfaces, by the effect of the morphology of surfaces on the measured hydrodynamic forces.
* _Slip length._ Measured slip length of the superoleophobic surface is obtained from the hydrophobic forces \(F_{hydro}\) and \(V/F_{hydro}\) according to Equation (1). Figure 10a shows the data of measured slip length as a function of \(Rsm\) roughness. With increased roughness from \(b1\) to \(b5\), the slip length of the superoleophilic surface in hexadecane and ethylene glycol increases with increasing \(Rsm\) roughness. Then the effective slip length is obtained according to Equation (11). Figure 10b  
Figure 9: Hydrodynamic forces \(F_{hydro}\) and \(V/F_{hydro}\) of a borosilicate sphere on superoleophobic surfaces immersed in (**a**) hexadecane and (**b**) ethylene glycol with varied \(Rsm\) roughness at a sphere velocity of 38.5 \(\upmu\)m/s.  
shows the data of effective slip length as a function of \(Rsm\) roughness. The results are similar to those of the superoleophilic surface, and show that all slip lengths are negative and remain constant from \(b1\) to \(b5\). This also can be explained by the existence of rough topography, leading to a discontinuity of boundary slip, and the values of \(\frac{\varepsilon}{\sqrt{|S^{\varepsilon}|}}\) remain constant with varying \(Rsm\). For the superoleophobic surfaces, the reference surface of the morphology in a Cassie regime remains an open question. Consider the case of drainage between sphere and rough surface; the reference surface should be located at the height of \(R_{q}\), as in a Wenzel regime. In this paper, application in micro-/nano-fluidic channels with rough walls on both sides has been considered, so the reference surface should still be considered as \(R_{q}\) of the roughness profile, which leads to a discontinuity of boundary slip.
## 2 Literature Review
### Object Detection
#### 2.1.1 Traditional Object Detection Methods  
Most classical object detection methods are usually developed based on low-level and mid-level features, such as color, shapes, edges, and contours. In the late 1990s and early 2000s, there were several milestones in object detection methods dominated by handcrafted features. Scale Invariant Feature Transform (SIFT) is one of them which transforms an image into a wide set of locally scale-invariant features. These scale-invariant features are invariant to image translation, rotation, scaling, illumination, occlusion, and 3D projection. Highly distinctive scale-invariant keypoints are further proposed to match individual features with features from known objects, and then the clusters belonging to the same object are identified through the Hough transform finally verified by least squares. In [17], a local feature descriptor, Histogram of Oriented Gradients (HOG), was first proposed. It counts the occurrences of gradient orientation in localized portions based on a dense grid of uniformly spaced cells and uses overlapping local contrast normalizations to improve accuracy. Despite being similar to SIFT descriptors, it is a significant improvement and gives excellent results for human detection. Because of the advantages of HOG, it has been an important architecture for many object detection methods. As an extension of HOG, the Deformable Part-based Model (DPM) [18] is the best classical object detection method. DPM achieves improvement in both precision and efficiency compared with the previous methods. It considers an object as a global template covering an entire object and a collection of part templates. Then the models are trained discriminatively through support vector machine. However, as the performance of handcrafted features reached its limits, object detection has fallen into a bottleneck period.
## 4 Analysis of Single-Factor Influence Law
### Influence of Grouting Volume on Compensated Level of Horizontal Displacement of the Tunnel  
The example in Section 3.1 was considered as the standard operating condition, and the grouting volume of a single sleeve valve pipe was set at 2, 4, 6, 8, and 10 m\({}^{3}\); the other parameters remained unchanged.  
Figure 9 delineates the influence of different volumes of grouting on the compensated level of horizontal displacement of the tunnel. First, the horizontal displacement of the tunnel followed a normal distribution under different grouting conditions. Second, as the amount of grouting increased, the horizontal displacement of the tunnel gradually increased. At a grouting volume of 2, 4, 6, 8, and 10 m\({}^{3}\), the maximum horizontal displacement in the center of the tunnel was 1.80, 3.31, 4.71, 6.16, and 7.51 mm, respectively. Third, as the amount of grouting increased, the affected area of the tunnel remained basically unchanged. The influence zone was chiefly concentrated in the range of \(y=-25\) m to \(y=25\) m.  
Figure 10 plots the relationship between the volume of grouting and the maximum horizontal displacement of the tunnel. As the grouting volume increased, although the maximum horizontal displacement of the tunnel slowly increased, the increasing trend gradually slowed down. This demonstrates that, in actual engineering, the amount of grouting can be increased to improve the corrective effect of grouting on the horizontal displacement of a tunnel. However, the volume of grouting should be controlled reasonably and should not be too large; indeed, an excessive volume of grouting has little effect on improving the grouting corrective effect. In addition, these findings are similar to the research results of [PERSON] et al. [2], which further proves the accuracy of the theoretical calculation method developed herein.  
Figure 8: Comparison of the compensated level of horizontal displacement of the tunnel calculated by the nonuniform expansion model with that determined by the uniform expansion model.
### [PERSON]  
German Remote Sensing Data Center (DFD), German Aerospace Center (DLR),  
D-82234 Oberpfaffenhofen, Germany; E-Mail: [EMAIL_ADDRESS];  
Tel.: +49-8153-28-3460; Fax: +49-8153-28-1445  
_Received: 29 March 2014; in revised form: 20 May 2014 / Accepted: 20 May 2014 / Published: 28 May 2014_  
**Abstract:** Fast crisis response after natural disasters, such as earthquakes and tropical storms, is necessary to support, for instance, rescue, humanitarian, and reconstruction operations in the crisis area. Therefore, rapid damage mapping after a disaster is crucial, _i.e._, to detect the affected area, including grade and type of damage. Thereby, satellite remote sensing plays a key role due to its fast response, wide field of view, and low cost. With the increasing availability of remote sensing data, numerous methods have been developed for damage assessment. This article gives a comprehensive review of these techniques focusing on multi-temporal SAR procedures for rapid damage assessment: interferometric coherence and intensity correlation. The review is divided into six parts: First, methods based on coherence; second, the ones using intensity correlation; and third, techniques using both methodologies combined to increase the accuracy of the damage assessment are reviewed. Next, studies using additional data (e.g., GIS and optical imagery) to support the damage assessment and increase its accuracy are reported. Moreover, selected studies on post-event SAR damage assessment techniques and examples of other applications of the interferometric coherence are presented. Then, the preconditions for a successful worldwide application of multi-temporal SAR methods for damage assessment and the limitations of current SAR satellite missions are reported. Finally, an outlook to the Sentinel-1 SAR mission shows possible solutions of these limitations, enabling a worldwide applicability of the presented damage assessment methods.  
**Keywords:** disaster; damage assessment; earthquake; tropical storm; SAR interferometry; InSAR; coherence; intensity correlation; Sentinel-1; multi-temporal SAR
## 7 Instrument Testing
### Zero-Field Compensation of the Triaxial Flux Gate Probe  
To eliminate the zero-field offset of the flux gate probe, the probe was placed in a zero-magnetic-field environment. The magnetic field strength output by the sensor in this environment represented the local zero-field compensation of the sensor. Specifically, the magnetic field reproduction system that is shown in Figure 24 was adopted for testing. The flux gate probe under test was placed at the center of the torque free coil within the magnetic shielding cylinder. A current of 0.08 mA was applied to the coil, generating a magnetic field of 8.88 nT within the shielding cylinder, and the flux gate was powered on.  
The forward output voltage \(U_{+}\) and the reverse output voltage \(U_{-}\) of the probe in the shielding cylinder were recorded. The zero-field compensation of the probe was calculated using Equation (3):  
\[B_{offset}=\frac{U_{+}+U_{-}}{2k_{B}} \tag{3}\]  
where \(U_{+}\) and \(U_{-}\) represent the forward and reverse output voltages of the target flux gate probe at zero magnetic field, respectively (\(\upmu\)V), and \(k_{B}\) is the commutation coefficient of the target flux gate probe (\(\upmu\)V/nT).  
Figure 24: A schematic diagram of zero-field compensation testing for the triaxial flux gate probe.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Indicator** & **Proposed Triaxial Flux Gate Probe** & **Mag-03 SS** \\ \hline Zero-field offset & \(\leq\)\(\pm\)5 nT & \(\pm\)30\(\pm\)50 nT \\ Temperature drift & \(\leq\)\(\pm\)0.09 nT/\({}^{\circ}\)C & \(\leq\)\(\pm\)0.1\(\pm\)0.6 nT/\({}^{\circ}\)C \\ compensation coefficient & Output voltage positive when & Output voltage positive when \\ Polarity & pointing north & pointing north \\ Noise & \(\leq\)8 pT Hz\({}^{-1/2}\) rms at 1 Hz & 6–20 pT Hz\({}^{-1/2}\) rms at 1 Hz \\ Frequency response and bandwidth & \(\leq\)\(\pm\)3\% kHz\({}^{-1}\); \(\geq\)3 kHz & \(\leq\)\(\pm\)5\% kHz\({}^{-1}\); \(\geq\)3 kHz \\ Scaling & 100 mV/\(\upmu\)T & 100 mV/\(\upmu\)T \\ Scaling error & \(\leq\)\(\pm\)0.5\% & \(\leq\)\(\pm\)0.5\% \\ Linearity error & \(<\)0.0015\% & \(<\)0.0015\% \\ Measurement range & \(\pm\)100 nT & \(\pm\)100 \(\upmu\)T \\ Operating temperature & \(\rightarrow\)40–85 \({}^{\circ}\)C & \(-\)10–50 \({}^{\circ}\)C \\ Orientation error & \(<\)0.5\({}^{\circ}\) & \(<\)0.5\({}^{\circ}\) \\ Installation error & \(<\)0.1\({}^{\circ}\) & \(<\)0.1\({}^{\circ}\) \\ Geomagnetic H, D, and Z components & High-precision continuous measurement & High-precision continuous measurement \\ Weight & 80 g & 185 g \\ \hline \hline \end{tabular}
\end{table}
Table 3: A comparison of the test results of the triaxial flux gate probe with instruments of the same type.  
The above steps were repeated for the other two axes. The results are presented in Table 4, which indicates that the zero-field compensation is \(\leq\pm\)5 nT.
## 5 Conclusions  
In this paper, a new SR-DCSK cooperative communication system based on modified code index modulation has been proposed, referred to as the MCIM-SR-DCSK-CC system. In the proposed system, the relay both forwards the source information bit to the destination and employs modified code index modulation to simultaneously convey additional information bits. The throughput, EE, and the data rates of the proposed system are compared with other systems. It is shown that the proposed system has better EE, high throughput, and high data rates in comparison with its competitors. The computational complexity and the memory requirement are analyzed. The theoretical BER expressions are obtained for the proposed system over AWGN and multipath Rayleigh fading channels,  
Figure 12: The comparison of the BER performance between the proposed system and the CIM-SR-DCSK-CC system over the AWGN channel.  
which are consistent with the simulation results. According to the simulation results, it is demonstrated that the BER performance will improve when the length of the chaotic signal decreases. And the BER performance of the proposed system runs better with \(M=4\) than \(M=8\) and \(M=16\). The comparison between the proposed system and the CIM-SR-DCSK-CC system demonstrates that the proposed system has better BER performance than its competitors.  
Conceptualization, B.Y.; data curation, B.Y., H.L. and X.L.; formal analysis, B.Y., H.Y. and Y.J.; investigation, B.Y. and Y.J.; methodology, B.Y.; writing--original draft, B.Y. and H.Y. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China, grant numbers 62373197 and 61971240; the Natural Science Foundation of Hunan Province of China, grant numbers 2023 JJ50116 and 2025 JJ70144; and the Scientific Research Fund of Hunan Provincial Education Department, grant number 24A0655.  
Not applicable.  
Data Availability Statement: Data are contained within this article.  
The authors declare no conflicts of interest.