esa-sceva/satcom-chunk-collection huggingface dataset:
## 4 Conclusions  
In summary, we employed a single InGaN-based micro-LED with an 80 \(\upmu\)m diameter and a 522 nm peak emission wavelength to build a UWOC link based on the total reflection at the air-water interface. It offered an alternative way to transmit data when the LOS UWOC link was interrupted. With the 7\({}^{\circ}\) total reflection angle, a maximum data rate of 300 Mb/s UWOC link was achieved at a BER of 3.10 \(\times\) 10\({}^{-3}\). A flow pump was applied to simulate waves to create frequency and amplitude variation at the air-water interface. The experimental results showed that the highly controlled water with its waves can result in limited data rates of 200 Mb/s and a BER of 2.57 \(\times\) 10\({}^{-3}\). For data-rate performance, an NLOS optical link approach for seawater conditions is very challenging and will require a future detailed investigation. Since the modulation mode in this experiment was NRZ-OOK, the amplitude would affect the SNR and the BER of UWOC links easily. Furthermore, we will bring in the PPM modulation mode to improve the communication performance of our UWOC system, which is insensitive to amplitude variation.  
Conceptualization, Z.L. (Zhijian Lv) and G.H.; methodology, Z.L. (Zhijian Lv); software, H.Y.; validation, G.H., R.C. and Y.L.; formal analysis, H.Y.; investigation, G.H.; resources, G.H.; data curation, G.H.; writing-original draft preparation, G.H.; writing-review and editing, Z.L. (Zhijian Lv); visualization, G.H.; supervision, W.Z.; project administration, C.Q.; funding acquisition, Z.L. ([PERSON]). All authors have read and agreed to the published version of the manuscript.  
This work was supported by Special Funds for the Cultivation of Guangdong College Students' Scientific and Technological Innovation (\"Climbing Program\" Special Funds, Project No. pdjh2020b0521), Key-Area Research and Development Program of GuangDong Province (Grant No. 2019B010925001), Shenzhen Overseas High-level Talent Innovation Team (Project Name: Micro-LED Displays Technology and Demonstration Innovation Team for Novel VR/AR Applications, Grant No. KQTD201708101103-13773), Guangdong Science and Technology funding (Project Name: High Speed Visible Light Communications based on RGB Micro-LED Arrays, Grant No. 2017B010114002), and Natural Science Foundation of Top Talent of SZTU(Grant No. GDRC202108).  
Not applicable.  
The authors wish to thank [PERSON], [PERSON], and [PERSON] for their valuable suggestions and supports. Thanks also to Chiao Tung University, Hong Kong University of Science and Technology, and Shenzhen Sitan Technology Co., Ltd.  
The authors declare no conflict of interest.
# Calculation Method of New Assembled Corrugated Steel Initial Support Structure of Highway Tunnel
## 3 Rotational Stiffness of Corrugated Steel Flange Joint
### Plane Strain-Spring Simplified Model and Its Validation  
In order to facilitate the design and calculation of corrugated steel lining, [PERSON] et al. [25] proposed the concept of the equivalent solid wall pipe section height of CSP, that is,  
\[h_{eq}^{\prime}=\sqrt{\frac{12 EI}{EA}} \tag{8}\]  
where \(h_{eq}^{\prime}\) refers to equivalent height. Based on the results of the equivalent stiffness of CSP, the flexural stiffness of CSP in Equation (8) is modified accordingly so as to obtain the following:  
\[h_{eq}=\sqrt{\frac{12\eta EI}{EA}} \tag{9}\]  
where \(h_{eq}\) refers to the modified equivalent height; \(\eta EI\) refers to the actual flexural stiffness of CSP; and \(EA\) refers to the axial stiffness of CSP.  
Therefore, Equation (9) demonstrates that while calculating the equivalent solid wall section height of CSP ensures stable flexural stiffness, it does not guarantee the accuracy of axial stiffness. Direct parameter-based calculations may lead to deviations in results. Hence, the concept of the equivalent solid wall section width of CSP is derived as follows:  
\[b_{eq}=\frac{A}{h_{eq}} \tag{10}\]  
where \(b_{eq}\) refers to modified equivalent height.  
Figure 12: Rotation–bending moment curve and simplified constitutive model of CSF (negative bending moment working condition).  
Through the equivalent calculations using Equations (9) and (10), the CSP section can be represented as an equivalent rectangular section. To accurately obtain the bearing characteristics of CSPs and surrounding rock, and to facilitate analysis of the interaction between CSP and back-sprayed concrete, the plane strain method is employed for computation. Utilizing the rotational stiffness results of the CSFJ, a torsional spring model is adopted to simulate the behavior of the CSFJ. Parameters of rotational stiffness are derived based on a two-stage linear model of the CSFJ proposed in Section 3.3. In conclusion, the plane strain-joint spring simplified model is formulated for the corrugated steel lining structure, presenting a calculation equation system described in Equation (11), which is the simplified calculation method for the corrugated steel initial support structure.  
\[\begin{cases}h_{eq}=\sqrt{\frac{12 pEI}{EA}}\\ \quad\quad b_{eq}=\frac{A}{h_{eq}}\\ \quad\quad M=f(\theta)\end{cases} \tag{11}\]  
To validate the accuracy of the simplified calculation method, a two-dimensional plane strain FE model was established in ABAQUS based on the three-dimensional fine joint model established in Section 3.2. The CSFJ was defined by \"rotational and translational\" connectors to ensure fixed distances between nodes. These nodes are coupled to the CSP end faces using coupling constraints, coinciding at the section center. The simulation results, as shown in Figure 10, indicate a good correlation between the calculations from the three-dimensional FE model and those from the simplified model.
# Analysis of the Efficiency of Slope Evacuation for Dense Crowds in Urban Street-Type Public Spaces
## 2 Related Works  
### Study on Street-Type Public Space  
[PERSON] carried out a micro-behavioral test of pedestrians in bottleneck space, discussed the results of narrow and wide bottleneck tests, and subsequently constructed a multi-class continuum model that can capture the key characteristics of pedestrian flow to explore the causes of crowd congestion in more depth [15]. [PERSON] proposed a method to improve the effectiveness of emergency evacuation for the complex spatial structure of streets and alleys in urban centers, aiming at simulating, evaluating, and optimizing cyclic evacuation by using Analogic software and an ArcGIS v10.2-based facility siting tool, so as to optimize the layouts of shelters and evacuation routes [16]. [PERSON] quantitatively assessed the risk of crowd congregation in street-type public spaces from the perspective of street space and crowd activity characteristics, and organized simulation experiments of crowd movement activities in field scenarios to quantitatively study the safety risk of crowd movement in urban street spaces [17].  
Overall, previous research on street-based public spaces has made significant contributions to understanding some aspects of pedestrian behavior and safety. However, these studies have typically focused on isolated factors such as bottleneck geometry, basic evacuation optimization, or risk assessment based on limited scenarios. They fail to comprehensively consider the highly dynamic and complexity of crowds in street spaces. In this paper, we present a detailed study of complex evacuation scenarios for sloped streets under dense crowd conditions.
# On the Virtual Cell Transmission in Ultra Dense Networks
## 3 Transmission Schemes Based on Virtual Cell Merging
### Virtual Cell Merging with IA Transmission  
In this section, the proposed IA algorithm based on the virtual cell-cluster is evaluated in terms of the average user spectral efficiency by simulations, as well as ZF and MRT.  
Figure 9 shows the average user spectral efficiency versus \(P/\sigma^{2}\) under different transmission schemes, such as ZF and MRT precoding with \(K=51\), \(\rho=10\), \(\rho=20\) and the user antenna number \(D=N_{0}=2\). With the proposed virtual cell merging scheme, where every three initial virtual cells form a virtual cell-cluster, the number of virtual cell clusters is 17. It is obvious that the average user spectral efficiency of the system increases with the increase of \(P/\sigma^{2}\) for all of the transmission schemes. Additionally, our proposed IA scheme based on low complexity virtual cell merging can reach higher average user spectral efficiency than ZF and MRT under different network densities, thus under different \(P/\sigma^{2}\). Besides, the interference from the data streams of other users increases with users antenna number. Nevertheless, we can eliminate these interferences by a global ZF, taking all of the data streams of all users into consideration. This requires us to know the global channel state information (CSI), and the information-bearing symbols of all of the users' data streams should be ready at all RBAs, since it is a global cooperative transmission. This would bring heavy burden to the fronthaul in UDN. Besides, the signal processing complexity could be prohibitively high if the number of RBAs is large enough. In the proposed IA scheme, which is a partial cooperative transmission, only intra-cluster CSI exchange and user data sharing are required. Therefore, it can scale well with the network size. Therefore, all of the transmission schemes are simulated in a partial cooperation or no cooperation regime, so that the corresponding signal processing complexities and signaling overheads are comparable. It can be seen clearly from Figure 9 that the proposed low complexity virtual cell merging based on IA can greatly outperform ZF and MRT in terms of the average user spectral efficiency.  
Figure 8: Cumulative distribution of user spectral efficiency for different transmission schemes. The results of \(K=50\), \(\rho=20\) and \(\rho=200\) are shown.
# Integrated System for Official Vehicles with Online Reservation and Moving Path Monitoring
## 3 System Build-Up and Test Results
### Communication Transmission Test  
To test whether the GPS data of the STB successfully transmitted to the background server, a test is performed through the third-party software Postman, as shown in Figure 26. The test data are put in the JSON format, and a request URL is sent to the by POST. The transmission result is displayed in the lower right. The status code is 200, which means the transmission is successful and the server-side receiver functions normally.  
For testing STB transmission, a program is created in C language and ported to the MCU on the backend server (Figure 27). When tested with the same request URL, the GPS path data and transmission time are successfully displayed on the server side (Figure 28).  
Figure 26: Third-party software Postman transmission test1.  
Figure 25: SSCOM read and return data diagram for using a vehicle.
## 5 Conclusions  
Many different approximate and numerical methods are available in the literature for solving linear and nonlinear VFIE. However, there is no effective direct procedure for solving them in closed form.  
In this paper, a direct operator method for the closed-form solution of some classes of VFIE was presented. An algorithm was developed for the case of VFIE with a linear Volterra convolution-type operator. The algorithm was implemented into the Maxima Computer Algebra System, and several problems were solved from the literature.  
The main advantages of the technique are that it calculates the exact solution of VFIE and avoids problems related to approximate and numerical methods, such as computer accuracy errors and method convergence and stability. In the case of nonlinear VFIE, it finds all the solutions, rather than only one, as is the case with most numerical methods.  
The only drawback of the method is that it requires the inverse of the Volterra operator and that all integrations must be performed analytically in general. In the special case of Volterra convolution-type operators, it depends upon the existence of the inverse Laplace transform of the involved functions. These limit the scope of the method to certain categories of functions, which makes perfect sense given the complexity of VFIE.  
Solving some problems has proven that the method will be useful in several fields of science and engineering. The method can be extended to other categories of Volterra operators, the mixed type VFIE and the VFIE in two or three dimensions.  
This research received no external funding.  
Not applicable.  
The author would like to thank the anonymous reviewers for their valuable comments.  
The authors declare no conflict of interest.  
The following abbreviations are used in this manuscript:  
\begin{tabular}{l l} IE & Integral Equation(s) \\ VIE & Volterra Integral Equation(s) \\ VFIE & Volterra-Fredholm Integral Equation(s) \\ CVIE & Convolution-type Volterra Integral Equation(s) \\ \end{tabular}
# Adsorption Separation of Various Polar Dyes in Water by Oil Sludge-Based Porous Carbon
## 2 Materials and Methods
### Modeling of the Adsorption Isotherms  
The removal efficiency (\(\upeta\)) and equilibrium capacity (\(q_{e}\), mg/g) of the three organic dyes were calculated using Equations (5) and (6). The adsorption kinetics were simulated using Equation (7) through (9); the adsorption isotherm model was simulated using Equations (10) and (11); the constant separation factor was calculated using Equation (12)and the separation factor was calculated using Equation (13); Thermodynamic modeling was carried out using Equation (14) to (15) [36;37]:  
\[\text{Removalefficiency}\ \%:\eta=\frac{C_{0}-C_{e}}{C_{o}}\times 100 \tag{5}\]  
\[\text{adsorptioncapacity}:q_{e}=\frac{(C_{0}-C_{e})\times V}{m} \tag{6}\]  
\[\text{Pseudo}-\text{first}-\text{order model}\ (\text{PFO}):q_{t}=q_{e}\Big{(}1-e^{-k _{1}t}\Big{)} \tag{7}\]  
\[\text{Pseudo}-\text{second}-\text{order model}\ (\text{PSO}):q_{t}=\frac{k_{2}q_{e}^{2}t}{1+k _{2}q_{e}t} \tag{8}\]  
\[\text{Intra particlediffusion}:q_{t}=k_{p}t^{0.5}+C \tag{9}\]  
\[\text{angmuir equation}:q_{e}=\frac{q_{m}K_{L}C_{e}}{1+K_{L}C_{e}} \tag{10}\]  
\[\text{Freundlich equation}:q_{e}=K_{F}C_{e}^{\frac{1}{2}} \tag{11}\]  
\[\text{Constant separation factor}:R_{L}=\frac{1}{1+K_{L}C_{0}} \tag{12}\]  
\[K_{e}=\frac{(C_{0}-C_{e})}{C_{e}}\times\frac{V}{m} \tag{13}\]  
\[\Delta G^{0}=-RT\text{ln}\,K_{e} \tag{14}\]  
\[\Delta G^{0}=\Delta H^{0}-T\Delta S^{0} \tag{15}\]  
where \(C_{0}\) and \(C_{e}\) (mg/L) denote the initial and equilibrium Pb\({}^{2+}\) concentrations, respectively; \(V\) (L) denotes the solution volume; \(m\) (g) is the adsorbent dose; \(q_{t}\) (mg/g) denotes the adsorbed Pb\({}^{2+}\) amount by the CG, CGPC, and PAC-CGPC materials at time t (h); k\({}_{1}\) (h\({}^{-1}\)) and \(k_{2}\) [g/(mg-h)] are the rate constants of the PFO and PSO models, respectively; \(q_{m}\) (mg/g) denotes the maximum adsorption capacity; \(K_{L}\) (L/mg) is the Langmuir isotherm constant; \(K_{F}\) [(mg/g)(mg/L)\({}^{n}\)] is the Freundlich adsorption affinity coefficient; \(1/n\) denotes the adsorption intensity of the Freundlich isotherm. \(1/n<0\), \(0<1/n<1\), \(1/n>1\) indicate irreversible, favorable, and unfavorable adsorption, respectively; \(R\) (8.314 J\(\cdot\)mol\({}^{-1}\cdot\)K) is the ideal gas constant; \(T\) (K) denotes the absolute temperature; \(K\) is the adsorption partition coefficient.
# A Digitally Enhanced Ethnography for Craft Action and Process Understanding
## 2 Related Work
### Kinematic Digitization
#### 2.3.3 MoCap  
MoCap is a technology used to capture and record the movement of people or objects and translate it into digital data. The process involves placing markers or sensors on the subject's body or object, which are then tracked by cameras or sensors to capture their motion. For craft practice recordings, the events of interest are practitioner postures and gestures. The main types of MoCap are optical and inertial. The choice of technique depends on the specific application and the requirements for accuracy, speed, and cost.  
Inertial MoCap is more suitable than optical in the cluttered space of workshops due to its reduced installation requirements and independence to occlusions, magnetic field disruptions, and gimbal locks. On the other hand, it exhibits a high degree of pervasiveness, as a MoCap suit has to be worn by the practitioner. This is a significant drawback in crafts that involve human touch and tactile sensing (e.g., pottery), as MoCap gloves provide accurate readings [63; 64] but have the limitation that they might obstruct the actions and sensations of the practitioner.  
Optical MoCap is significantly less pervasive, as only markers are worn. This type of MoCap is more accurate than inertial, but it is sensitive to occlusions and requires a setup only possible when indoors or in spatially constrained environments. As such, optical MoCap is suitable for crafts exercised indoors without machinery that gives rise to occlusions, such as silversmithing, woodcarving, and knitting.  
MoCap has been used to record and analyze practitioner motion in 3D. Multi-view optical MoCap has been proposed to capture crafting gestures in 3D [65]. RGB-D cameras were employed in [66]. Inertial MoCap accurately recorded articulated motion for crafting gestures in [67; 68; 69; 70]. In [71], MoCap was employed for both hands and tools.  
The digital assets are 4D motion recordings, called animations. The applicability of MoCap and video modalities depends on the type of environment. For the digitization of motion using video, markerless visual methods are employed [72]. Albeit significantly less accurate than MoCap, they solely require a camera and are the only way to treat archive video. Inertial MoCap is more suitable than optical in the cluttered space of workshops due to its reduced installation requirements and increased occlusion robustness.
## 4 Simulation  
To evaluate the control performance, we considered two simulation scenarios involving the comparative models of the proposed ESN-MPC and EDT-MPC. The proposed ESN-MPC model employs the optimization problem formulated in Equation (21). This formulation does not include the effect of the dead-time. The prediction obtained using the ESN provides future disturbance information. To consider the effect of the dead-time, the input signal is applied to the future control. The optimal control for the future is defined at  
Figure 3: The basic network architecture of the ESN model. The solid arrows indicate the weights that were fixed randomly and remained constant during the learning process; the dashed arrows indicate the weights to be trained.  
the current time. Instead of solving the optimization problem in real-time, the future optimized signal is buffered and applied at the appropriate time to address the dead-time. The time difference between the current and MPC optimization times, termed the time margin, can be set arbitrarily regardless of the dead-time, as illustrated in Figure 2. The reasonable requirement is that the time margin can be set longer than the sum of the calculation time and dead-time without sacrificing the control performance. In contrast, the conventional EDT-MPC model includes the effect of the dead-time, as indicated in Equation (32). However, the conventional EDT-MPC model does not include the time margin. Instead, to perform a comparison with the proposed method, the performance of the future predictive control was evaluated by setting the artificial dead-time in the EDT-MPC to the same value as the time margin in ESN-MPC.  
The performances of the two methods were evaluated via computer simulations. All simulations were performed in MATLAB, R2019a installed on a PC with a clock speed of 3.1 GHz and 16 GB of RAM in a Mac OS 10.12 environment.
# Airborne GNSS Reflectometry for Water Body Detection
## 1 Introduction
In this regard, there is a trade-off between spatial resolution and global coverage. The maximum temporal resolution of GNSS-R ground-based and airborne applications is equivalent to the code repetition rate of GNSS signals (e.g., 1 ms for GPS C/ A). However, a longer integration time increases the Signal-to-Noise (SNR) ratio of the signal, which is important when studying land reflections due to the weak nature of the reflected signals. This article is dedicated to the study of airborne GNSS-R techniques for water body detection using a low-altitude airborne carrier with high rate reflectivity measurements. We develop a radar technique for automatic GNSS signal segmentation in order to differentiate surfaces, and in particular water bodies, in landforms based on the changes in the reflectivity measurements associated to different areas of reflection. Such measurements are derived from the GNSS signal amplitudes. We have shown in a previous work [44] that in a 1-bit quantization digital receiver, the digitized GNSS signals are independent of the automatic gain control and thus dedicated GNSS signal processing techniques provide direct observation of the GNSS signal amplitude. In the context of this work, we estimate 20 ms rate of the GNSS signals amplitudes using 20 ms rate observations of the signals components. We estimate high rate (50 Hz rate) reflectivity measurements in order to cope with the rapid displacement of the satellites footprints along the airborne experiment. We propose a mixture of an on-line/off-line change point detection and localization algorithm for the segmentation of the GNSS signals into stationary parts associated to different mean signal levels. We develop a GNSS-R setup on-board a lightweight airborne carrier that can achieve the high temporal and spatial resolution requirements of our application. We show, along a real flight experimentation, that the proposed radar technique detects in-land water body surfaces along the flight trajectory. We also show that we can localize, at meter accuracy, the edges of the detected water body surfaces, i.e., the border between water and land. Based on the foregoing, this chapter is organized as follows: Section 2 describes the airborne bi-static GNSS-R configuration. Section 3 introduces the airborne GNSS-R system that we utilize in this work. Section 4 demonstrates the on-line/off-line change model that is proposed for GNSS signal segmentation. In Section 5, we introduce the context of the real flight experimentation. Analyses of the data acquired during the flight for water body detection and edge localization are provided in Section 6. Discussion and conclusions are provided in the final two sections.