esa-sceva/satcom-chunk-collection huggingface dataset:
## 2 Materials and Methods
### Materials Characterisation  
The properties of the obtained materials were investigated via different characterisation techniques. A LabRAM Aramis Jobin-Yvon Horiba \(\upmu\)-Raman equipped with a He-Ne laser source (785 nm) was used for Raman spectroscopy measurements. FT-IR was performed using a JASCO model 4600 instrument (Easton, PA, USA). Grazing incidence XRD (GIXRD) was employed to analyse the crystallinity of samples using a X'Pert Pro diffractometer, working with the Cu K\(\alpha\) radiation. A field emission scanning electron microscope (FEG-SEM, JSM-7001F, JEOL (Tokyo, Japan)) equipped with an Energy-Dispersive X-ray Spectroscopy (EDXS-INCA PentaFETx3, Oxford Instruments (Abingdon, UK)) analyser was used to examine morphology and composition, whereas TEM analysis was performed in order to add structural information at a microscopic scale (S/TEM TALOS F200S, ThermoFisher, Waltham, MA, USA). UV and visible (UV-Vis) absorption spectra were measured using a VARIAN Cary 5000 UV-Vis-NIR spectrophotometer over a wavelength range of 200 to 800 nm. The Kubelka-Munk function (Equation (1)) and the Tauc equation were used to evaluate the direct bandgap of the synthesized materials:  
\[F(R)=\frac{(1-R)^{2}}{2R} \tag{1}\]  
where \(R\) is the reflectance of the sample.  
The Tauc equation for direct electronic transitions is described in Equation (2):  
\[(\alpha hv)^{2}=A\big{(}hv-E_{g}\big{)} \tag{2}\]  
where \(\alpha\) is the optical absorption coefficient; \(hv\) is the incident photon energy in eV; \(A\) is the material-dependent absorption constant; and \(Eg\) is the energy bandgap.  
X-ray photoemission spectroscopy (XPS) measurements were performed on the thin film coatings to understand the surface chemical states of the elements. The X-ray source was a monochromatized Al K\(\alpha\) (1486.6 eV) source, and the spectra were collected from an electrostatic hemispherical electron energy analyser with \(\pm 8^{\circ}\) of acceptance angle. The X-ray beam incidence was at an angle of 45\({}^{\circ}\) on the surface of the samples and all spectra were acquired in normal emission conditions with an initial base pressure of \(2\times 10^{-9}\) mbar.  
Figure 1: Schematic showing the synthesis of iron urchin (FeOx), g-C\({}_{3}\)N\({}_{4}\), and FeOx/g-C\({}_{3}\)N\({}_{4}\) composites via different procedures.  
The calibration of the data was performed using the C 1 s native peak present on the surface of the samples.
## 1 Introduction
Furthermore, making the measurement along fixed paths has the following benefits: (1) For a space-based implementation it facilitates extensive validation and calibration options (e.g., aircraft,in situ_ towers, radiosonde launches, NOAA's AirCore, _etc._) which is very difficult to do with current and planned satellite missions for GHG monitoring to the precision needed for separating biogenic and anthropogenic sources; (2) It provides significant improvements in precision and accuracy for regional monitoring due to the long time series of measurements, both day and night, enabling measurement accuracies through averaging to levels required to separate anthropogenic sources from biogenic sources and sinks; (3) It enables cross calibration opportunities among receivers that are along the same atmospheric path simultaneously and illuminated by the same transmitter, due to the ability to relocate the receivers; (4) For a ground-based implementation it provides direct measurement of GHG time-varying fields and be used to directly measure flux over large areas and long path lengths. Although several other open path techniques exist [7; 8; 9; 10; 11; 12; 13; 14], LAnTeRN is a different implementation which simultaneously transmits and receives both the on and the offline wavelengths. This key difference makes many of the noise sources including scintillation common to both wavelengths and since this is a ratiometric measurement they cancel in the ratio. For the more traditional lidar case of MFLL this approach also reduces impacts of varying surface reflectance as well. We believe this is a significant benefit to this measurement approach relative to other common open-path approaches, such as tunable diode laser absorption spectroscopy (TDLAS). In 2011 and 2012, Exelis developed a proof-of-concept demonstration of a LAnTeRN transmitter and receiver pair. The system was designed to demonstrate the ability to build separate transmitter and receivers capable of maintaining sufficiently accurate timing to enable long integration times; to validate a high-fidelity performance model, leveraged from an optical communications model developed by Exelis in a prior effort; and to demonstrate the measurement at power levels predicted for a geostationary implementation. The theory, model description, a description of the instrument, results from experiments performed, and some potential applications of the measurement approach are presented in the following sections.
## 3 Related Work
A new MAC protocol is designed in [16] to avoid the channel being busy due to acknowledgment packet transmission without any additional CCA. However, it cannot avoid collisions due to the hidden terminal problem. Since, one acknowledgment packet is about 22 symbols and one backoff slot is about 20 symbols, the authors in [17] propose one segementized CCA to increase the possibilities of transmission by neglecting the channel busy condition for the shake of the ACK packet. However, it cannot avoid the end of the data packet instead of the ACK one. Apart from this, the authors in [18] design an analytical model to predict the energy consumption and throughput for the saturated and unsaturated traffics. However, these works have not considered the buffer status of the devices to improve the energy efficiency. The authors in [19] have introduced the Markov model to calculate the impact of energy consumption based on the probability of delivering a packet. A detailed analysis of the energy consumption of the Body Area Networks (BAN) with respect to packet inter-arrival time is discussed in [20]. However, the authors have not considered the external WiFi interferences with the ZigBee devices. The authors in [21] have designed one generalized technique to investigate the performance for the slotted CSMA/CA scheme in the IEEE 802.15.4 standard. The majority of the present analytical models consider ideal channel conditions, though wireless channels are prone to burst errors. Hence, the authors in [22] have designed one three-dimensional Markov model to evaluate the performance of the IEEE 802.15.4 MAC scheme considering the burst channel errors. However, they have not considered the collisions due to the hidden terminal problem in the network. The authors have designed the time critical services in [23] and the priority-based adaptive MAC schemes for the WSNs in [24]. However, none of these schemes focus on how to enhance the reliability of the network. To analyze the reliability, the authors in [25] design one analytical model to study the performance of MAC with the assumption that only ZigBee devices are present in the network. However, they have not considered the external network interferences. In this paper, we not only propose a new superframe structure to avoid the hidden terminal problem in the network to enhance the reliability, but also design one channel access mechanism based on the current buffer condition of the device to reduce the packet drop rates. In addition, one analytical model is proposed to evaluate the performance in terms of throughput, delay, energy consumption and reliability considering the presence of both WiFi and ZigBee devices in a system.
# Visible-Light CDMA Communications Using Inverted Spread Sequences
## 2 Optical CDMA with MUI Cancellation
### Generalized MPSC
Codewords of the original MPSC constructed from \(\text{GF}(p)\) can also be generated using the above procedure by setting the parameter \(m=1\). In the original algorithm [16] for MPSCs, codewords are generated by cyclic-shift operation of prime sequences or its binary representation, i.e., prime sequence code (PSC). Although the algorithm for original MPSCs is different from that for GMPSCs, the resulting sets of codewords are equivalent in the case of \(m=1\). The cyclic-shift operation for an original MPSC corresponds to the operation \({}^{i}+\mathbf{h}_{j}^{\prime}\) in Equation (2) for a GMPSC. Hereafter, we refer to both original and generalized MPSCs as MPSCs. \begin{table}
\begin{tabular}{c c c c} \hline
**Group** & \(\mathbf{x}_{i}\) & **Code \(\mathbf{C}^{*}\)** & **Generalized MPSC** \\ \hline \multirow{6}{*}{\(i=0\)} & \multirow{6}{*}{\(x_{0}=0\)} & \(\mathbf{c}_{0,0}^{*}=\left(0,\ 0,\ 0,\ 0\right)\) & \(\mathbf{c}_{0,1}=\left(1000\ 1000\ 1000\ 1000\right)\) \\ \cline{3-4}  & & & \(\mathbf{c}_{0,1}^{*}=\left(1,\ 1,\ 1,\ 1\right)\) & \(\mathbf{c}_{0,1}=\left(0100\ 0100\ 01000\ 1000\right)\) \\ \cline{3-4}  & & & \(\mathbf{c}_{0,2}^{*}=\left(\alpha,\ \alpha,\ \alpha,\ \alpha\right)\) & \(\mathbf{c}_{0,2}=\left(0010\ 0010\ 0010\ 010\right)\) \\ \cline{3-4}  & & & \(\mathbf{c}_{0,3}^{*}=\left(\alpha^{2},\ \alpha^{2},\ \alpha^{2},\alpha^{2},\alpha^{2}\right)\) & \(\mathbf{c}_{0,3}=\left(0001\ 0001\ 0001\right)\) \\ \hline \multirow{6}{*}{\(i=1\)} & \multirow{6}{*}{\(x_{1}=1\)} & \(\mathbf{c}_{1,0}^{*}=\left(0,\ 1,\ \alpha,\ a^{2}\right)\) & \(\mathbf{c}_{1,0}=\left(1000\ 0100\ 0010\ 001\right)\) \\ \cline{3-4}  & & & \(\mathbf{c}_{1,1}^{*}=\left(1,\ 0,\ \alpha^{2},\ \alpha\right)\) & \(\mathbf{c}_{1,1}=\left(0100\ 1000\ 0001\ 010\right)\) \\ \cline{3-4}  & & & \(\mathbf{c}_{1,2}^{*}=\left(\alpha,\ \alpha^{2},\ 0,\ 1\right)\) & \(\mathbf{c}_{1,2}=\left(0010\ 0001\ 1000\ 0100\right)\) \\ \cline{3-4}  & & & \(\mathbf{c}_{1,3}^{*}=\left(\alpha^{2},\ \alpha,\ 1,\ 0\right)\) & \(\mathbf{c}_{1,3}=\left(001\ 0010\ 0100\ 1000\right)\) \\ \hline \multirow{6}{*}{\(i=2\)} & \multirow{6}{*}{\(x_{2}=\alpha\)} & \(\mathbf{c}_{2,1}^{*}=\left(1,\alpha^{2},\ 0\right)\) & \(\mathbf{c}_{2,1}=\left(0100\ 001\ 001\ 000\right)\) \\ \cline{3-4}  & & & \(\mathbf{c}_{2,2}^{*}=\left(\alpha,\ 0,\ 1,\ \alpha\right)\) & \(\mathbf{c}_{2,2}=\left(001\ 000\ 0100\ 0001\right)\) \\ \cline{3-4}  & & & \(\mathbf{c}_{2,3}^{*}=\left(\alpha^{2},\ 0,\ \alpha,\ 1\right)\) & \(\mathbf{c}_{3,3}=\left(0001\ 1000\ 00100\right)\) \\ \hline \multirow{6}{*}{\(i=3\)} & \multirow{6}{*}{\(x_{3}=\alpha^{2}\)} & \(\mathbf{c}_{3,3}^{*}=\left(\alpha^{2},\ 0,\ \alpha,\ 1\right)\) & \(\mathbf{c}_{3,3}=\left(0001\ 1000\ 00100\right)\) \\ \cline{3-4}  & & & \(\mathbf{c}_{3,3}^{*}=\left(\alpha^{2},\ 0,\ \alpha,\ 1\right)\) & \(\mathbf{c}_{3,3}=\left(0001\ 1000\ 00100\right)\) \\ \hline \end{tabular}
\end{table} 
Table 1: An example of generalized MPSC (\(q=4\)).
## 4 Conclusions  
In summary, g-C\({}_{3}\)N\({}_{4}\) nanosheets and graphene decorated with the ultrafine Co-species heterostructure can act as a reinforced polysulfide barrier toward enhancing Li-S batteries. This modification layer can not only enable effective polysulfide affinity through the physical barrier and chemical binding but also simultaneously catalyze the conversion of intermediate polysulfides. As a result, Li-S cells assembled with Co@g-C\({}_{3}\)N\({}_{4}\)/G-PP separators matched with S/KB composites (up to ~70 wt% sulfur in the final cathode) exhibit excellent rate capability and good cyclic stability. A high specific capacity of ~860 mAh g\({}^{-1}\) at 2.0 C as well as a capacity-fading rate of only ~0.035% per cycle over 350 cycles at 0.5 C can be achieved. This bifunctional separator can even endow a Li-S cell at a low current density to exhibit excellent cycling capability, with a capacity retention rate of ~88.4% at 0.2 C over 250 cycles. Furthermore, a Li-S cell with a Co@g-C\({}_{3}\)N\({}_{4}\)/G-PP separator possesses a stable specific capacity of 785 mAh g\({}^{-1}\) at 0.2 C after 150 cycles and a superior capacity retention rate of ~84.6% with a high sulfur loading of ~3.0 mg cm\({}^{-2}\). This effective polysulfide-confined separator holds good promise for promoting the further development of high-energy-density Li-S batteries.  
**Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/molecules28020588/s1](https://www.mdpi.com/article/10.3390/molecules28020588/s1)]([https://www.mdpi.com/article/10.3390/molecules28020588/s1](https://www.mdpi.com/article/10.3390/molecules28020588/s1)). Refs. [42; 60; 67; 68; 69; 70; 71; 72; 73; 74] are cited in Supplementary Materials.  
**Author Contributions:** Methodology, Formal analysis, Writing--original draft, S.W.; Resources, Investigation, X.L.; Conceptualization, Project administration, Supervision, Writing--review & editing, Y.D. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the National Natural Science Foundation of Guangdong Province (grant no. 2022A1515010173), the National Natural Science Foundation of China (grant no. 21875071), the Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technology (FC202214), and the Professorial and Doctoral Scientific Research Foundation of Huizhou University (2021 JB019/15602210128).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Data are available upon reasonable request.  
**Conflicts of Interest:** The authors declare no conflict of interest.
## 6 Conclusions  
This study was initiated to identify the internal compaction behavior for asphalt mixture using image analysis. The study focused on measuring volumetric characteristics and their effects on internal friction changes during compaction. Based on the image analysis of aggregate behavior and mixture volumetric study, the following findings can be provided:  
1. Image processing was developed to conduct a better analysis of the internal structure of the asphalt mixture, including detailed image processing techniques that solved the difficulty regarding the separation of objects by equalizing, filtering for denosing, and thresholding. The results of the t-test show that it is reliable and confident to evaluate the internal structure interpretation of the mixture with good repeatability.
2. The aggregate orientation and the energy index were highly dependent on the compaction temperature. At high viscosity, the aggregates were not sufficiently able to slide and be moved for rearrangement; thus, the mixture needs more energy for compaction. There is an optimum compaction temperature at which a preferred orientation exists to provide a low-energy index. Excessive compaction temperature is unnecessary to obtain a better rearrangement of aggregates. Conversely, an excessive compaction temperature was found to be responsible for increasing the interaction of aggregates and causing a reduction in the amount of asphalt for lubrication.
3. The results of the aggregate orientation and energy index studies show that the compaction temperature changes the asphalt mixture volume and causes internal friction changes due to aggregate interactions. The effect of the mixture volume change on the aggregate friction behavior was evaluated by the V\({}_{\text{eac}}\) and the P\({}_{\text{ba}}\). Mixture acquires more V\({}_{\text{eac}}\), at which an optimum compaction temperature produces low CEI and CFI values. Despite being higher than the optimum temperature for the PG62-28 mixture, the V\({}_{\text{eac}}\) decreased by 0.4% and 0.35% of the P\({}_{\text{ba}}\), which flowed into the aggregates. This volumetric change in the V\({}_{\text{eac}}\) and P\({}_{\text{ba}}\) can produce a large frictional interaction between aggregates and eliminate the viscosity effect to increase a better rearrangement of aggregates.
4. The aggregate interaction effect was introduced to modify the More-Coulomb compaction concept, and it explains the additional friction that is produced due to the change in the volumetrics of mixture. The additional friction parameter is sensitive to the compaction temperature.  
Figure 12: Modifying the Mohr-Coulomb compaction concept by adding the change in internal friction.  
**Author Contributions:** Regarding the authors' participation in the research, [PERSON] planned and performed the laboratory test, analyzed experiments, and drafted the manuscripts. [PERSON] guided this study, provided valuable comments, and revised the manuscripts.  
**Funding:** This research received no external funding.  
**Conflicts of Interest:** The authors declare that there is no conflict of interests regarding the publication of this paper.
## 4 Analysis of Test Results  
### Result of Transmission Wave Test Method  
The AGI-BWG instrument was used to test the hammering signals of the four pre-stressed pipes in the test beam. The test data and analysis results are as follows. The singular line is the excitation signal. The even-numbered line is the signal at the receiving end.  
The tested signal of pipeline 1 is shown in Figure 17. The result of the spectral analysis is shown in Figure 18.  
The tested signal wave velocity of pipeline 1 is 4340 m/s, and the peak frequency is 3662 Hz.  
Figure 17: Tested time history diagram of pipeline 1 signal.  
The tested signal of pipeline 2 is shown in Figure 19. The result of the spectral analysis is shown in Figure 20.  
The tested signal wave velocity of pipeline 2 is 4325 m/s, and the peak frequency is 3448 Hz.  
Figure 19: Tested time history diagram of pipeline 2 signal.  
Figure 18: Tested spectrum diagram of pipeline 1 signal.  
* Pipeline 3  
The tested signal of pipeline 3 is shown in Figure 21. The result of the spectral analysis is shown in Figure 22.  
The tested signal wave velocity of pipeline 3 is 4310 m/s, and the peak frequency is 3143 Hz.  
Figure 21: Tested time history diagram of pipeline 3 signal.  
Figure 20: Tested spectrum diagram of pipeline 2 signal.  
Figure 22: Tested spectrum diagram of pipeline 3 signal.  
Figure 23: Tested time history diagram of pipeline 4 signal.  
The tested signal wave velocity of pipeline 4 is 5274 m/s, and the peak frequency is 6516 Hz.  
The test results in Figures 17-24 are summarized in Table 3. It can be seen that in the transmission wave test method, with the increase in the degree of slurry emptying, the propagation speed of the transmitted wave increases. The degree of signal energy attenuation slows down, and the frequency shifts towards high frequencies.
## 1 Introduction
It is a crucial manner for power consumption, battery life, processing load, processing time and hence latency. Using time slots on GFDM allows using the hexagonal time-frequency allocation for the shorter symbol duration. Based on these problems, we adopt GFDM with hexagonal time-frequency allocation for shorter symbols duration and merely the filtering processing by using polyphase decomposition for low computational complexity. Firstly, we propose a hexagonal GFDM model using polyphase decomposition to remedy the low complexity and latency problems. We update the traditional GFDM model with hexagonal time-frequency allocation. In the traditional GFDM, the users' symbols are transmitted among the time- and frequency-shifted of a prototype filter. Unlike traditional GFDM, the time and frequency allocation of the hexagonal GFDM is hexagonal, as given in Figure 1b. Accordingly, users' symbols are transmitted with hexagonal allocated versions of the prototype filter. Polyphase decomposition is a good solution for filtering operations due to its lower complex structure [21; 22]. Thus, based on the traditional GFDM structure, we derivate the hexagonal GFDM by using polyphase decomposition.
## 6 Conclusions  
It is demonstrated that data from the Chinese HJ-1B satellite allow the mapping of impervious surface areas and analyses at a reasonable spatial resolution. The object-based textural characteristics are crucial to separate impervious and pervious areas for such medium resolution images. This research expands our scientific understanding of the effects of landscapes patterns in quantifying the relationships between ISA and other landscape features. The object-based spatial analysis method seem to have a high potential for urban heat island detection and population monitoring. Planners may then counteract impacts of urbanization in a sense that UHI can be mitigated or reduced by optimizing the urban landscape. However, we also confirm that the extraction of impervious surfaces is still challenging because of the complexity of urban and suburban landscapes, particularly at medium spatial resolution. Future impervious surface analyses should incorporate more detailed urban morphology information to improve the accuracy and stability of urban pattern studies.  
**Acknowledgments:** The authors would like to thank Prof. [PERSON] from the Institute of Remote Sensing and Digital Earth (RADI) of the Chinese Academy of Sciences for providing the HJ-1B data. This research was partly funded by the Austrian Science Fund (FWF) through the GLScience Doctoral College (DK W 1237-N23), and partly funded by Beijing Key Laboratory of Urban Spatial Information Engineering (NO. 2017202).  
**Author Contributions:** [PERSON] conceived, designed and carried out the experiments and wrote the majority of the paper. She finished the manuscript at the Department of Geoinformatics-Z-GIS, University of Salzburg, Austria; [PERSON] supported [PERSON] when planning and structuring the paper and contributed to the paper, particularly to the introduction, discussion and conclusion sections.  
**Conflicts of Interest:** The authors declare no conflict of interest.