esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Legal Challenges Posed by Mega-Constellations to Existing International Space Law Regime
### Principle of Equitable Access
#### 4.1.2 Application of Equitable Access Principle to Mega-Constellations
Therefore, even if international law currently prohibits the appropriation of outer space, aligning with the principle that space exploration should be open to all nations, the rise of mega-constellations challenges the balance between rights, principles, and obligations in space law. In conclusion, firstly, the Outer Space Treaty defines outer space as the \"province of all mankind\", aiming to ensure equitable access to and use of space for all nations. However, mega-constellations challenge this principle by disproportionately occupying valuable orbital slots, thereby restricting access for other space actors and potentially interfering with their space operations. National authorizations for satellite launches often do not align with international obligations, leading to the situation where the increasing number of mega-constellations exacerbates concerns about orbital congestion and equitable access. Secondly, the historical apprehensions articulated in the Bogota Declaration reflect ongoing fears among developing nations regarding their ability to access outer space amidst growing orbital congestion. With thousands of active satellites and tens of thousands of sizable debris objects already in orbit, the deployment of mega-constellations significantly heightens the risk of congestion, which could impede future space missions and compromise the sustainable use of outer space. Furthermore, the expansion of mega-constellations poses substantial threats to the astronomy community. The reflective surfaces of numerous satellites hinder ground-based astronomical observations and interfere with radio signals, thereby obstructing essential astronomical research. Despite the existing freedom to explore and utilize outer space, the absence of specific legal frameworks addressing the encroachment of rights presents significant challenges. The Outer Space Treaty's provisions regarding no harmful interference and equitable access fail to provide clear remedies for the issues arising from the proliferation of mega-constellations. Consequently, there is a pressing need for updated international regulations to balance the rights and interests of all space users, ensuring that outer space remains a shared and accessible domain for the benefit of all of humanity.
## 1 Introduction
Since Lyapunov stability techniques play a critical role in the design and stability analysis of adaptive systems [49; 64], the fractional Lyapunov method is applied to investigate the practical stability behavior of the proposed model and establish efficient stability criteria. The proposed results are new and complement the existing results proposed in [31] for the impulsive case considering a nabla fractional discrete operator. Moreover, the derived stability results can be applied to synchronization issues for discrete fractional neural networks via impulsive controllers, which have not been studied before. The rest of the paper is organized as follows. Section 2 is devoted to the introduction of the impulsive control discrete fractional model, which generalizes some existing models proposed in product form design. The necessary background related to discrete fractional calculus is also provided. The notion of the global practical Mittag-Leffler stability is defined for the constructed neural network model. Some definitions and lemmas concerning the fractional Lyapunov method are finally given. The main practical stability results for the new impulsive fractional discrete model are established in Section 3. Examples and a discussion of the results proposed are presented in Section 4. Some conclusions are stated in Section 5.
## 2 Principle and Signal Processing Method
### Sidelobe Suppression  
When the STFrFT window is rectangular, the output waveform envelope of the LFM pulse processed by STFrFT shows properties similar to those of a sinc function. In addition to the mainlobe, there are a series of sidelobes extending on the time axis. The first sidelobe close to the mainlobe is the largest, with a peak value of 13 dB lower than the mainlobe one, and the peaks of the other sidelobes  
Figure 3: STFrFT with a rectangular window (time normalizes with respect to T). (a) Compressed narrow pulse of the sinc-shape by STFrFT and (b) zoom-in of the main lobe in (a) with 3-dB width, which is equal to \(1/KT\), and a peak sidelobe ratio of approximately 13 dB.  
decrease successively. These sidelobes can overwhelm the signals of some smaller events nearby, resulting in inaccurate measurements. Based on the pulse compression radar, different windows can be used to suppress them [30]. However, suppressing the sidelobes also widens the mainlobe of the output waveform envelope and decreases its peak value, that is, sidelobe suppression comes at the expense of signal-to-noise ratio loss and poor distance resolution. The Hamming window is a sidelobe suppression technique commonly used in pulse compression radars [30], and we used it as an STFrFT window. Figure 4a illustrates the numerical calculation results when using the Hamming window. A comparison between Figures 4a and 3a shows that the peak sidelobe ratio is greatly improved after using the Hamming window, but the mainlobe is widened and its peak value is reduced. In particular, according to the characteristics of the Hamming function, the peak sidelobe ratio can be increased to about 41 dB and the mainlobe can be expanded by 1.47 times [30], as shown in Figure 4b.
## 3 Signal Path Modeling and Analysis  
In this system, information communication is implemented through magnetic induction communication technology based on the FSK control method. The carrier frequencies of forward and backward information transfer are 1.7 MHz and 1 MHz, respectively. It is obvious that the system information carrier frequencies are much larger than the power carrier frequency. According to superposition theorem, information transmission and  
Figure 4: The output power with respect to phase shift angle \(\phi\).  
power transmission are discussed separately. Therefore, when high frequency information is being transferred, the low frequency loop can be regarded as a short circuit to simplify the analysis of the information coupling loop. This section separately analyzes forward and backward information transmission.
# An Efficient Stochastic Constrained Path Planner for Redundant Manipulators
## 2 Related Work
Being a sum of factors, however, entails that the optimization of the cost function cannot ensure that the end effector achieves a given position and orientation exactly. A significant branch of stochastic planners is based on Rapidly-exploring Random Trees (RRTs) [13]. These efficient algorithms usually work by building two trees rooted at the beginning and end configurations of the trajectory. A simple greedy heuristic is presented in [14,15] to grow the trees and explore the high dimensional space while trying to connect both trees. The planner has been successfully applied to a variety of path planning problems for the computation of collision-free grasping and manipulation tasks. The growing phase of the tree considers a random generation of new samples in order to explore new solutions in the joint space, but does not include any feature that enables the optimization of the generated trajectories that are, essentially, random. A problem that arises in some of these RRT-based planning algorithms is that, often, a continuous cyclic path in task space does not correspond to a closed path in joint space. As a result, the behavior is not predictable and constitutes a risk if, for instance, a human agent is operating in the vicinity of the robot. In [16,17], a variation of an RRT-based planning algorithm is proposed that satisfies the constrains of the path and, additionally, ensures the attainment of joint trajectories that are cyclic. The method presented here presents the following characteristics:  
* Handles kinematic restrictions on the end effector exactly and does not rely on a discretization of the task space or configuration space;
* Exploits the null-space at each configuration along the path to maximize the manipulability of the robot while avoiding obstacles;
* Produces smooth trajectories that can be directly commanded to the robot without the need for a posterior smoothing phase;
* Delivers a fitting experimental performance for challenging motion problems.
# Untargeted Metabolomic Profiling of _Fructus Chebulae_ and _Fructus Terminaliae Billericae_
###### Abstract  
This study aims to identify the differences in metabolites between _Fructus Chebulae_ (FC) and _Fructus Terminaliae Billericae_ (FTB). Untargeted metabolomics was used to analyze differentially expressed metabolites (DEMs) with ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). A grand total of 558 metabolites were detected, with 155 in positive ion mode and 403 in negative ion mode. Further differential analysis yielded 110 and 87 significantly different metabolites, which were mainly polyphenols, flavonoids, terpenoids, and alkaloids. Analysis of KEGG data showed that differentially expressed metabolites (DEMs) in both positive and negative ion modes were found to be enriched in 5 and 18 metabolic pathways, respectively, with metabolic pathways being the most enriched among them. In sum, this study reveals the differential metabolic profiles of FC and FTB and provides support for their further applications in traditional Chinese medicine.  
Fructus Chebulae; Fructus Terminaliae Billericae; metabolomics; differential metabolites; KEGG analysis Article
## 1 Introduction  
The accurate positioning, navigation, and timing (PNT) services can be provided by the Global Navigation Satellite System (GNSS), and it has been widely used in many areas such as agriculture [1], weather monitoring [2], time and frequency transfer [3], and disaster monitoring [4]. As of the end of April 2022, there are about 120 GNSS satellites, including GPS, GLONASS, Galileo, BDS-2, BDS-3, and QZSS systems, which can provide PNT services to users around the world [5, 6, 7]. The available satellites, frequency, and PRNfor each system are listed in Table 1. For GNSS, the observation data quality on the receiver side directly determines the result of precise data processing at the GNSS server and user end. The positioning performance at the GNSS user side plays a key role in the quality of GNSS service, and the broadcast ephemeris directly affects the performance of real-time navigation and positioning. The stations located in the Asia-Pacific region can receive the signals broadcasted by five navigation satellite systems at the same time. Therefore, it is worthy to investigate and evaluate the performance of GNSS observation data quality, broadcast ephemeris, and positioning performance in the Asia-Pacific region. For the observation data quality of GNSS: the BDS-3 satellites signals were evaluated by [PERSON] et al. ; the B1I/B2I/B3I signals of the BDS-2 satellites, L1/L2/L5 of the GPS Block IIF satellites, and E1/E5a/E5b of the Galileo satellites are also evaluated for comparison in their study [8]. The observation data quality of the BDS-3 signal was studied and analyzed by [PERSON] et al. [9]. The signal quality of BDS-2 and BDS-3 satellites was evaluated by [PERSON] et al. [10]. The observation data quality and positioning performance of BDS/QZSS satellites were studied by [PERSON] et al. [11]. The data quality of BDS/GPS/GLONASS satellites was investigated by [PERSON] et al. [12]. The signal quality of Galileo/BDS/GPS satellites was evaluated by [PERSON] et al. [13]. It can be seen that previous studies about signal quality mainly focus on single and dual systems; the investigation and comparison of observation data quality among five GNSS systems in Asia-Pacific regions are limited and still needs further study. In the context of GNSS broadcast ephemeris accuracy assessment, the GPS/GLONASS/BDS/Galileo/QZSS broadcast ephemeris was evaluated by [PERSON] et al. [14], but the BDS-3 satellite constellation had not been built at that time. After the BDS-3 satellites were launched, their broadcast ephemeris orbit and clock offset accuracy were evaluated by many scholars [15; 16], and the comparison of broadcast ephemeris orbit and clock offset accuracy between BDS-2 and BDS-3 was also conducted [17]. However, with the modernization of GNSS satellites, the performance of broadcast ephemeris orbit and
# Mapping a Guided Image Filter on the HARP Reconfigurable Architecture Using OpenCL
## 5 Guided Image Filtering
### OpenCL Code
#### 5.2.4 Sliding Window  
In the guided image filter algorithm, each pixel is calculated from neighboring input pixels in a window with radius \(r\). The computational complexity is linear in the number of pixels of the image, regardless of window size site [15; 16]. When the pictures are calculated sequentially, left to right, top to bottom, most pixels in the sliding window can be reused and each pixel is fetched one by one from memory. The memory usage is optimized by streaming data into a shift register which contains relevant data for the calculation of the output. The shift register is organized as a linear array of \(2 rw+1\) pixels in the sliding window, where \(w\) is the image width, see Figure 8. The generic code for a shift register is shown in Listing 4. In this code fragment, the data in variable shift_register is shifted over one position by looping over all indices. Then a new pixel is loaded from global memory into shift_register[0]. By spatially unrolling this loop using the pragma unroll, all shifts are executed in the same clock cycle, and a pipelined shift register is obtained. Both for-loops are fully unrolled using the pragma unroll. \(f_{mean,r}\) is then calculated by adding all values in the area and dividing this value by the size of the window. Fully unrolling the nested loops with iteration count \(2r+1\), increasesthe logic resources demand. The maximum guided image filter radius \(r\) is limited by the available FPGA resources, see Section 6.1.
# Deep Learning-Based Low-Frequency Passive Acoustic Source Localization
## 4 Results
### Case 3
#### 4.3.3 Discussion  
The multi-task CNN utilizes the same input feature for performing two related tasks--classifying the azimuth angle, \(\theta\), and the elevation angle, \(\alpha\). A commonly encountered problem in multi-task learning is \"negative transfer\", wherein one or more tasks can dominate the training/learning process and hurt the performance of other tasks. The tasks whose performance is hampered tend to perform better in a single-task model compared with a multi-task model [37]. Both tasks are learned reasonably well in the case of a monopole source (Table 5) but a clear case of negative transfer is observed for the sinusoidal plane wave source (Table 6). The prediction of \(\alpha\) dominates the training, which is expected as it is the easier of the two tasks (\(N_{2}<N_{1}\)). However, the prediction accuracy values for \(\theta\) are less than what were obtained when a single-task model was used for predicting \(\theta\) in case 2(ii). A suggested way to overcome negative transfer is to weigh the individual losses from the two tasks appropriately such that they are on the same scale [37].
# Silicon Integrated Nanophotonic Devices for On-Chip Multi-Mode Interconnets
## 3 Silicon Multi-Mode Routing Devices
### Silicon Multi-Mode Crossings
In this work, MFL is constructed on a silicon slab based on the following equation:  
\[\mathrm{n_{eff}(R)=n_{max}/[1+(R/R_{0})^{2}]} \tag{11}\]  
where \(\mathrm{n_{eff}(R)}\) is the index distribution, \(\mathrm{n_{max}}\) Is the maximum index, \(\mathrm{R_{0}}\) is the maximum radius. To realize the gradient index map, the silicon slab is covered by a layer of metamaterial film comprised of a two-dimensional array of nano-rods whose effective medium index can be controlled by varying the nano-rod filling factor. Due to the perfect-imaging feature of MFL, the incident light will propagate through the crossing section and then form its self-image regardless of the mode order, so that all the input modes can be preserved throughout the crossing section. This MFL-based crossing can provide low losses (\(\mathrm{IL}<0.3\) dB) and low crosstalk (\(\mathrm{XT}<-20\) dB) for the first two TM modes (i.e., \(\mathrm{TM_{0}}\), \(\mathrm{TM_{1}}\)). The footprint is also as small as \(18\times 18\)\(\mathrm{\SIUnitSymbolMicro m^{2}}\). Later, another MFL-based three-mode crossing was reported based on the grayscale lithography technology [202]. The MFL-based crossing is considered as a universal and scalable scheme that could work for any higher-order mode since the imaging process is independent from the mode order. Moreover, conjugate imaging of MFL also enables multiple cross-over pathways at a single junction, which allows for a multi-port star-crossing with an enhanced integration density. In Table 6, we summarize the reported silicon multi-mode crossings. For most of the reported structures, low losses (\(\mathrm{IL}<0.5\) dB), low crosstalk (\(\mathrm{XT}<-20\) dB) and a broad bandwidth (BW \(>80\) nm) can be achieved, whereas the mode capacity is still restricted to two or three modes. Although the MFL-based structures have offered a clear prospect for an arbitrarily large capacity, there is still a lack of experimental demonstrations for a higher capacity (e.g., more than four channels) due to the complex index map. Therefore, the next goal should be developing simple and reliable multi-mode crossings. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Ref. **} & \multirow{2}{*}{**Year**} & \multirow{2}{*}{**Size (\(\mathrm{\SIUnitSymbolMicro m^{2}}\))**} & \multirow{2}{*}{**Capacity**} & \multicolumn{2}{c}{**IL (dB)**} & \multicolumn{2}{c}{**XT (dB)**} & \multicolumn{2}{c}{**BW (nm)**} \\ \cline{5-10}  & & & & **Sim. ** & **Exp. ** & **Sim. ** & **Exp. ** & **Sim. ** & **Exp. ** \\ \hline
[197] & 2016 & \(30\times 30\) & 2 & 0.25–1.7 & 1.5 & \(<\)\(-32\) & \(<\)\(-18\) & 100 & 80 \\
[199] & 2017 & \(21\times 21\) & 2 & 0.3–0.5 & 1.82 & \(<\)\(-30\) & \(<\)\(-18\) & 100 & 90 \\
[200
# Software Defined Networking Architecture for Energy Transaction in Smart Microgrid Systems
###### Abstract  
A decentralized power distribution network consisting of smart microgrids introduces opportunities to trade with energy called transactive energy. However, research studies in the existing literature suggest that several standardized information models for TE do not meet the network architecture's reliability, flexibility, and security requirements. This limitation is mainly due to the static nature of traditional IP infrastructure. To achieve these requirements in the network architecture, this study investigates the optimized application of software-defined network architecture for transactive energy in smart microgrid systems. Through literature research, unique design approaches in an SDN architecture are identified that improve the reliability, flexibility, and security of the SDN architecture. These design approaches include a decentralized controller network layout, redundant link configuration, a mesh network topology, and data encryption. The proposed solution uniquely combines these design approaches into a single optimized SDN solution for TESMS. To validate the improvements of the findings from the literature research, each design approach is simulated in this study using Mininet SDN emulator and AnyLogic system simulation software. The proposed solution is then applied to a use-case scenario that shows the improvements required for TESMS. The use-case scenario shows significant improvement in the data path uptime. An improvement of 0.27% is achieved, which equates to a 2 h per month increase in the data path uptime. The results of the simulation show that the proposed SDN architecture improves the reliability and flexibility of a traditional SDN network. Furthermore, enabling encryption between the nodes improves the security of the SDN architecture.  
transactive energy; smart micro grid; software-defined network; SD-WAN; network design Article
# Assessment of GNSS Galileo Contribution to the Modernization of CROPOS's Services
## 4 Discussion
By comparing the number of satellites included in the observation RINEX 3.03 files, the solutions obtained with VPPS (GGG), and VPPS (GAL-only), it was confirmed that \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Solution** & & **\#SAT** & **PDOP** & **Hz Precision** & **Vt Precision** \\ \hline \multirow{2}{*}{GGG} & MAX & 26 & 1.620 & 0.0043 & 0.0112 \\ \cline{2-6}  & MIN & 15 & 1.012 & 0.0033 & 0.0050 \\ \hline \multirow{2}{*}{GAL-only} & MAX & 7 & 3.910 & 0.0124 & 0.0218 \\ \cline{2-6}  & MIN & 5 & 1.602 & 0.0044 & 0.0062 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Range of #SAT, PDOP, Hz Precision, and Vt Precision estimation values for solutions based on ‘GGG’ and ‘GAL-only’ satellites. VPPS (GGG) solutions were gained by the contribution of GPS, GLO, and GAL satellites, whereas the BDS satellites have not contributed to the VPPS solution. Moreover, the number of satellites in the first several recorded epochs in RINEX 3.03 observation files were compared to the closest VPPS solutions based on GGG and GAL-only observations. The analysis is given for all sessions containing static occupations. The results are summarized in Table 4, where the times are given for the start of each observation series (static, VPPS (GGG), VPPS (GAL-only)). The last session (ninth session) was not taken into consideration since there was a large time span between the instant of VPPS (GGG) and VPPS (GAL-only) observations and the start of the static session, and therefore, such a comparison would not be meaningful. From the data given in Table 4, it can be inferred that there is a small difference (0-1) between the number of GAL satellites included in the VPPS (GAL-only) solutions and GAL satellites recorded in the RINEX observation file. That difference (which is always in favor of a static observation file) can be attributed to the fact that the visible GAL observations are recorded in the RINEX files whereas, in the VPPS solutions, only those GAL satellites simultaneously visible by the network and the receiver were contained. The time difference between the epochs of observation files and VPPS solutions is in the range 4-33 min, but those time differences have not caused a significant difference in the number of GAL satellites contained in the solutions, owing to the slowly changing visibility of GAL satellites. A similar conclusion can be drawn considering the number of GGG satellites contributing to the VPPS (GGG) solution and the number of recorded GGG observations in the RINEX observation file: although the numbers of SV are similar, the difference between the epochs of observation (4-33) has contributed to the difference in number of SV contained in the solution (0-4). Additionally, this can be regarded as a confirmation that the VPPS solution relies on the observations (corrections) of the GGG satellites.