esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Comparative Analysis of the Proposed GSMLI Topology  
The proposed generalized structure was compared with other recent topologies. The performance of various parameters such as numbers of diodes (\(N_{diode}\)), switches (\(N_{sw}\)), capacitors (\(N_{cap}\)), drivers (\(N_{dr}\)), and \(TSV_{p,h,r}\), and cost function per level (\(CF/N_{L}\)), are shown in Figure 2. It may be noted that all these topologies are designed to generate seventeen levels of output voltage. Cost function per level (\(CF/N_{L}\)) is defined as  
\[CF=\left(N_{sw}+N_{cap}+N_{dri}+N_{diode}+\alpha^{*}TSV\right)\times N_{source}\]  
Figure 2: Comparison curves: (**a**) number of switches vs. number of levels, (**b**) number of switches vs. number of levels, (**c**) number of switches vs. number of levels, and (**d**) total standing voltage (TSV) (per unit) vs. the number of levels.  
Here, \(\alpha\) represents the contribution of \(TSV\) in the cost function  
The comparisons are carried out among the levels of generalized structure of the proposed topology and other topologies. The comparison is conducted in terms of numbers of switches, drivers, capacitors, diodes, and \(TSV\) when all generated the same levels. From Figure 2a, it can be observed that the number of switches required in the generalized structure in both methods (first and second) is less than the number of switches required by other topologies for the same number of levels. It can also be seen from Figure 2a that the number of switches required in the second method generalized structure is less than the switches required by the first method of generalized structure. From Figure 2b,c, it is clear that the number of driver circuits and capacitors required in GSMLI in both methods (first and second) is less than the number of drivers and capacitors required by other topologies for the same number of levels. In [28], there is no capacitor, which is why it is not shown in Figure 2c.  
From Figure 2d, it is clear that the TSV (in per unit) in GSMLI (second method) is less than the other topologies when all generated the same number of levels. TSV (in per unit) in the GSMLI (first method) is higher than the CHB and in [30] when all generated the same number of levels; however, it requires less switches, drivers, and capacitors compared to CHB and in [30].
# Null Subcarrier Index Modulation in OFDM Systems for 6G and Beyond
## 4 Proposed NSC-OFDM-IM
### Receiver Design and Detection
#### 4.1.2 Visualization of the Proposed NSC-OFDM-IM Scheme  
For the sake of the clear understanding and visualization of the proposed NSC-OFDM-IM scheme, the following illustrative example is given in Figure 6.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Null Carrier Index** & **Corresponding** & **Corresponding** \\
**(Extracted from LLR** & **Decimal Value (\(\tilde{z}\))** & **Binary Sequence (\(\tilde{p}_{0}\))** \\
**Subgroup (\(\tilde{i}\)))** & \\ \hline
1 & \(\tilde{i}-1=0\) & \(\tilde{p}_{0}=\{00\}\) \\
2 & \(\tilde{i}-1=1\) & \(\tilde{p}_{0}=\{01\}\) \\
3 & \(\tilde{i}-1=2\) & \(\tilde{p}_{0}=\{10\}\) \\
4 & \(\tilde{i}-1=3\) & \(\tilde{p}_{0}=\{11\}\) \\ \hline \hline \end{tabular}
\end{table}
Table 2: The proposed scheme index demodulator (\(\tilde{M}=4\)).  
Let us suppose that we have a bit stream that will be sent over 12 subcarrier frequency points, regardless of whether they are set to an active or inactive state. The frequency domain localization of the active and inactive subcarriers for the given example is illustrated in Figure 7.  
The bit stream is divided into three subgroups. This means that we have three complex subgroups, and each has four consecutive carrier locations in the frequency domain. In each bit subgroup, the first \(p_{0}\) bits are used for the null carrier index, and the remaining \(p_{1}\) bits are used for complex mapping. The \(p_{0}\) bits used in the given example are \(\{10\}\), which are in the first subgroup, \(\{01\}\), which are in the second subgroup, and \(\{00\}\), which are in the third subgroup. They are first converted to their corresponding decimal value and then fed into the index mapper to obtain the indices of the null subcarrier locations in the complex subgroups.  
After the decimal conversion of the \(p_{0}\) bits, the corresponding indices of the null subcarriers are obtained as 3 in the first complex subgroup, 2 in the second complex subgroup, and 1 in the third complex group. The remaining subcarrier indices in the subgroups are \(\{1,2,4\}\) in the first complex group, \(\{1,3,4\}\) in the second complex group, and \(\{2,3,4\}\) in the third complex group. They indicate the locations of the active subcarriers in the frequency domain. In the given example, the corresponding complex data of the \(p_{1}\) bits modulate these active subcarriers.  
Figure 6: Example of the NSC-OFDM-IM transmitter.  
Figure 7: Frequency domain illustration of the modulated example carriers.
## 2 System Modeling
### UAV Base Dynamics and Control  
The UAV is modeled as a rigid body of mass \(m_{B}\) with a moment of inertia around its barycenter of \(I_{B}\). Its parameters are based on those of the commercial octocopter S1000 Spreading Wings manufactured by DJI (Shenzhen, China).  
In the discussion of the system dynamic model, the following reference frames are used: the fixed inertial reference frame, denoted by the subscript \(I\), and the body-fixed reference frame, denoted by the subscript \(B\), whose origin is positioned on the base Center of Gravity (CoG). The vertical axis of the body frame, \(z_{B}\), is set to be parallel to the thrust force direction and is parallel to the inertial frame vertical axis, \(z_{I}\), when the UAV is in a hovering state. The inertial frame vertical axis, \(z_{I}\), is aligned with the gravity force vector and points in the opposite direction. These reference frames are illustrated in Figure 1.  
For the sake of simplicity, we consider a planar problem where the UAV is constrained to move in the \(x_{I}-z_{I}\) plane. The state of the UAV is described through the following generalized coordinates: \(x_{b}\) is the horizontal position of its CoG in the inertial frame, \(z_{b}\) is its vertical position, and \(\phi\) is the roll angle (about the \(y_{I}\) axis).  
The simplified dynamics of the UAV [16] are described by the following equations:  
\[\begin{array}{c}m_{B}\ddot{x}_{b}=-U_{1}sin(\phi)\\ m_{B}\ddot{z}_{b}=-m_{B}g+U_{1}cos(\phi)\\ I_{B}\dot{\phi}=U_{2}\end{array} \tag{1}\]  
where \(U_{1}\) and \(U_{2}\) are the thrust control force and the rolling control torque exerted by the propellers, respectively, and \(g\) is the gravitational acceleration.  
These control actions are determined through a PID controller, which aims to minimize the UAV vertical displacement and roll angle, i.e., correct any deviations from the hovering state. The PID controller equations are as follows:  
\[\begin{array}{c}U_{1}=-k_{P}zz-k_{Dz}\dot{z}-k_{Iz}\int_{0}^{t}zdt\\ U_{2}=-k_{P\phi}\dot{\phi}-k_{D\phi}\dot{\phi}-k_{I\phi}\int_{0}^{t}\phi\ dt \end{array} \tag{2}\]  
It has to be noticed that, since multicopters are underactuated systems, the horizontal position of the UAV cannot be controlled independently but only by applying a combination  
Figure 1: Reference frames for the UAV (DJI S1000). The inertial reference frame is denoted by the subscript \(I\), while the body-fixed reference frame is denoted by the subscript \(B\).  
of thrust force and roll torque. The coefficients of the PID controller used in the simulations are summarized in Table 1[9].  
The UAV base, in addition to the reaction torque and force due to the movement of the manipulator, is subject to the action of the following external forces:  
* Gravity (\(m_{B}\)S);
* The net thrust, \(U_{1}\), and roll torque, \(U_{2}\), determined by the control law (exerted through the propellers);
* Aerodynamic disturbances (\(F_{w}\), modeled in Section 4).  
The generalized coordinates and the external forces/torques (except the manipulator reaction force/torque) acting on the UAV are illustrated in Figure 2.
# Energy Efficient Data Transmission for Sensors with Wireless Charging
## 3 Transmission in Limited \(K\) Periods  
If the sensors stay in the range of wireless charging for a limited period of time, then the sensors may not receive enough energy to transmit all the data kept in the memory. Some data may have to wait to be transmitted in the future. In such a situation, we try to solve the problem to maximize the amount of data that could be transmitted in the limited \(K\) periods. We first consider a simple situation where \(C=E\), that is, the energy received in each period equals battery capacity. A battery is fully charged after only one period of wireless charging. This is the case where energy should be used as soon as possible. We then study the problem with \(C=2E\), where a battery can be filled in two periods of wireless charging. Finally, we discuss the general problem with \(C=mE\), where a battery can be filled in \(m\) periods of wireless charging.
# Risk-Based Hybrid Light-Weight Ship Structural Design Accounting for Carbon Footprint
## 1 Introduction
Autonomous vessel design is another branch of ship design that could benefit from using risk assessment procedures effectively. An example was provided in [17], which proposed a methodology targeting the initial safety management strategy but suggested the need to develop the strategy further to evolve during vessel design and construction. [PERSON] et al. [18] developed a process for the risk assessment of maritime autonomous surface ships, including safety, security, and cybersecurity in the initial design phase considerations. One of the main challenges in a broader application of risk-based approaches is the need to rely on reliable data, which cannot be readily available, especially for low-added value ships or ships subjected to customisation. [PERSON] and [PERSON] [19] moved a step toward such a direction by suggesting a risk-based design using the combination of Goal-Based Standards and a Safety Level Approach applied to a fishing vessel fleet. As indicated in [20], further risk assessment can be improved by accounting for the Energy Efficiency Design Index (EEDI), which introduces environmental aspects in the conceptual ship design. The study in [12] was extended concerning the shipbuilding energy efficiency and carbon footprint [11]. The initially designed hybrid lightweight ship hull structure in [12] is analysed here concerning the cost-benefit for identifying the merit of the steel and hybrid designs of the bulk carrier where aluminium honeycomb panels replaced the inner side shell of the cargo holds. The risk of progressive structural failure during ship operations and environmental pollution during shipyard construction and ship voyages is analysed. The present study develops a risk-based formulation for identifying an optimal ship hull structural design where the aluminium honeycomb sandwich panels replace a part of steel ship hull structures. The reliability estimate is based on the ultimate limit state employing the first-order reliability method. The risk due to the hull structural failure is evaluated over the ship's service life as a function of the design solution. The carbon footprint and cost to mitigate the impact of the complete steel and hybrid ship hull structural design solutions implemented as a sustainable life cycle solution are analysed, accounting for the structural degradation. The proposed formulation can quantify the best time for the first repair, the beta-reliability index's associated level, and the repair cost. Employing the developed risk-based design formulation, the best design solution reduces the weight, cost of the ship, and carbon footprint, better corrosion resistance and increases cargo transport. The developed risk-based formulation can be used as a design tool in defining modern ships' optimal design solutions, accounting for the environmental pollution associated with the manufacturing process and ship operation, which is one of the primary objectives of the international maritime community, where some latest measures have been adopted for example in [21].
# Evaluating the Reliability of Powder Bed Fusion for Biomedical Materials: An Experimental Approach
## 3 Results
### Manufacturing the SLM Specimens from Pure Ti Powder  
Laser power in the range of 100-160 W was used to manufacture specimens from pure Ti powder. As shown in Table 5, when the laser power exceeds 120 W, manufacturability decreases, and the ultimate tensile strength (R\({}_{\mathrm{m}}\)) is lower. Structures produced using a laser power of 120 W are recommended because they exhibit lower residual stresses compared to those manufactured at 100 W. Generally, higher laser power leads to increased residual stresses.  
For pure titanium, a laser power of 100 W was insufficient to provide the energy density needed to create an adequate melt pool. Only at 120 W was the PBF process optimal for producing reliable metal parts. Consequently, the authors chose to measure the Poisson's ratio only for the specimens manufactured at 120 W.  
During these experimental tests, a lower laser power (100 W) resulted in higher surface roughness compared to parts produced with 120 W. This finding was also confirmed by the Rz roughness parameter measurements presented in Table 5.
## 5 Conclusions  
In this study, a new type of 2D piezoelectric phononic crystal with thickness and a square hollow as well as convex structures was designed and established. First, a theoretical analysis was introduced to illustrate the dispersion relationship of the designed piezoelectric phononic crystal. Subsequently, the band structure diagram was drawn, which demonstrated that the multi-order broadband complete bandgaps were generated. The widest bandgap was as high as 1247.74 Hz, while the narrowest bandgap was 532.34 Hz. To gain a clearer understanding of the formation of the bandgaps, the vibration modes of the upper and lower boundaries of each bandgap were analyzed and the iso-frequency curves were computed to illustrate the anisotropy of elastic waves propagating through the piezoelectric phononic crystal.  
Further, by comparing the band structure with the elastic waves attenuation constant curves in the IX and MI directions, the frequencies of the bandgaps were found to be consistent with the attenuation regions and the attenuation level of each bandgap is able to possess unique characteristics. The fourth bandgap had the strongest ability to suppress elastic waves, whereas the second bandgap was the weakest. Furthermore, the transmission loss curve showed that the series circuit configuration reduced the decaying performance of the elastic waves, and the attenuation range of the bandgaps did not vary with the different external circuits. It is worth noting that piezoelectric material is added to the established phononic crystal as matrix material, which makes it possible to alter the intrinsic property of phononic crystal through the external circuit, and can lay the foundation for the active control of solid piezoelectric phononic crystal.  
Finally, the factors (thickness and square hollow side length) affecting the bandgaps of the piezoelectric phononic crystal were discussed. The findings indicated that to obtain a lower and wider stopband, the thickness of the piezoelectric phononic crystal should be increased while decreasing the side length of the square hollow. The presented study and the numerical model could be beneficial for enriching the scope of piezoelectric phononic crystals in vibration isolation and promoting their practical applications.  
Conceptualization, Z.M. and J.L.; data curation, Z.M.; formal analysis, Z.M.; funding acquisition, J.L.; investigation, J.L.; methodology, Z.M. and J.L.; project administration, Q.M.; resources, S.L.; supervision, J.L.; validation, Z.M., J.L. and S.L.; visualization, Q.M.; writing--original draft, Z.M.; writing--review and editing, J.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Natural Science Foundation of Hainan Province (grant numbers 122 MS004 and 2019 RC068), and the National Natural Science Foundation of China (grant number 51909050).  
Not applicable.  
The authors declare no conflict of interest.
# Modified Equation of Shear Strength with Respect to Saturation
## 3 Materials and Experimental System
### Soil-Water Characteristic Curve Test  
In order to validate the rationality of the formula, we adopted a pressure-plate system to control the suction and define the parameters of the SWCC (vG numerical model). The experimental device is shown in Figure 4, which was made up of a soil sample chamber, pressure control equipment as well as an outflow measurement device [32]. The silty sand was put in the soil specimen chamber. The pressure control equipment controlled air pressure applied to the soil specimen. The outflow measurement device can collect and measure water saturation in order to calculate the variation in the water saturation from the bottom outflow. The silty sand was compacted in a ring (diameter: 70 mm, height: 20 mm) to achieve a dry density of 1.5 t/m\({}^{3}\), 1.6 t/m\({}^{3}\), and 1.7 t/m\({}^{3}\). Before loading, the soil specimens in the rings were saturated with water. After loading, the specimen's soil-water characteristic test at a temperature of 25 \({}^{\circ}\)C (normal temperature) was measured using the pressure plate method (Figure 5) or the pressure plate test; the test started with a saturated sample. The degree of saturation was determined by weighing the wet soil sample.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \
\begin{tabular}{c} **Specific** \\ **Gravity (G\({}_{\text{s}}\))** \\ \end{tabular} & \(\omega\) **(\%)** & **e** &
\begin{tabular}{c} **K \(\times\) 10\({}^{-10}\)** \\ **(m s\({}^{-1}\))** \\ \end{tabular} & \multicolumn{3}{c}{**Particle Composition (\%)**} \\ \cline{2-6}  & & **0.05–2 (mm)** & **0.002–0.05 (mm)** & **<0.002 (mm)** \\ \hline
2.70 & 32.5 & 1.45 & 1.74 & 87.8 & 10.6 & 1.6 \\ \hline \hline \end{tabular}
\end{table}
Table 1: The physical properties of silty sand.  
Figure 4: General scheme of the soil–water characteristic curve test system.
# Multi-UAVs Communication-Aware Cooperative Target Tracking
## 2 Problem Description and System Model
### Observation Model  
Usually, each UAV is equipped with a local sensor such as radar, infrared sensor, or a camera. With the development of sensor technology, some of the most advanced sensor devices, such as SAR/GMTI radar and ESM, have gradually been installed on small and medium-sized UAV platforms. This paper mainly considers direction-finding sensors represented by photoelectric/infrared imaging sensors, ranging sensors represented by ultrasonic/laser radar, and a combination of both. Additionally, this paper focuses on how to maintain a stable tracking of the target in presence of noise in target information, rather than studying the sensor itself.  
We assume that the UAVs' flight altitude remains the same. Then, the UAVs and the target can be projected onto horizon for analysis. Doing so, a simplified airborne sensor observation model can be obtained as shown in Equation (4).  
\[z_{i}=\left[\begin{array}{c}r_{i}\\ \varphi_{i}\end{array}\right]=h(X_{t})=\left[\begin{array}{c}\sqrt{\left(x_ {i}-x_{t}\right)^{2}+\left(y_{i}-y_{t}\right)^{2}}\\ \arctan\frac{y_{i}-y_{t}}{x_{i}-x_{t}}\end{array}\right]+\left[\begin{array}[ ]{c}v_{r,i}\\ v_{\varphi,i}\end{array}\right] \tag{4}\]  
where \(r_{i}\) is the distance between the \(i\)-th UAV and the target, \(\varphi_{i}\) the angle between the \(i\)-th UAV and the target, and \(h(\cdot)\) the observation function. \(v_{i}\) represents the observation noise, and \(v_{i}=\left[\begin{array}{c}v_{r,i}\\ v_{\varphi,i}\end{array}\right]\sim N(0,R_{i})\) in which \(R_{i}\) is the covariance matrix. Usually, for the safety of UAV as well as the need of target tracking, an UAV is not supposed to be too close to the target, which we call a minimum observation distance.
## 3 Methodology
### Data Processing  
The data packets transmitted and received for ship AIS data contain information about the ship's identity, position, speed, heading, and other details. AIS data can be categorized into two main types: dynamic information and static information. Dynamic information includes the ship position, course over ground, speed over ground, navigation status, timestamp, and more. It is automatically updated by the AIS transponder's position sensor, with the transmission interval adjusting automatically based on changes in ship speed and heading. Typically, dynamic information is transmitted every 3 to 5 s. Static information includes the IMO number, call sign, MMSI number, vessel name, ship type, dimensions, and other details. This information is manually input by users and is transmitted at a longer interval, usually every 6 min.  
For this research, we have chosen AIS data from the Yangtze River Basin on 17 March 2023 as our study object. This region is one of China's most important inland waterway transportation areas, featuring an extensive network of waterways and a high volume of vessel traffic. Moreover, the complex river channels, hydrology, and navigation challenges in this area make it an ideal case for evaluating ship trajectory prediction performance. Specific AIS data fields are shown in Table 1, listing only a portion of the data fields for reference.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**MSGTIME** & **MMSI** & **LON** & **LAT** & **SOG** & **COG** & **NS** \\ \hline
17 March 2023 & 413 xxx567 & 114.2015 & 30.44428 & 0 & 354 & 1 \\
17:51:10 & 413 xxx965 & 114.1501 & 30.59679 & 0 & 331 & 1 \\
17 March 2023 & 413 xxx381 & 114.0261 & 30.22972 & 5.2 & 311.9 & 0 \\
17 March 2023 & 413 xxx688 & 114.4845 & 30.67789 & 0 & 342 & 1 \\
17:51:10 & 413 xxx182 & 114.4793 & 30.67895 & 2 & 251.3 & 0 \\
17 March 2023 & 413 xxx371 & 114.0638 & 30.09095 & 3.9 & 242.6 & 0 \\
17:51:10 & & & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Structure of Raw AIS Data.  
Figure 2: A representation of the trajectory prediction problem.  
The following will provide a detailed explanation of each part of the AIS trajectory data processing method proposed in this paper.
# GIS-Based Cluster and Suitability Analysis of Crop Residues: A Case Study in Yangon Region, Myanmar
## 2 Materials and Method  
### Study Area  
The study area comprises 43 townships in the Yangon Region, which is in the delta area regarding the ecological environment. The selected area is examined to assess the potential locations of treatment facilities based on available clusters of agro residues, refer to Figure 1. In 2019, the Yangon region had a population of over eight million [29] and covered an area of 10,171 square kilometers [30]. It is one of the highest-production areas of rice in Myanmar [31]. Additionally, the major crops in the region are paddy, green gram, groundnut, sunflower, sesame, and sugarcane [32]. Regarding meat from livestock production, cattle, buffalo, pigs, chickens, ducks, and quails are primary sources of meat production [33].