esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Results
### XGBoost-Based Model for Ornamental Classification from Tabular Data  
#### 3.1.1 Median of Experts Marks  
The XGBoost model achieved an accuracy of 91.67% on the test set, demonstrating its effectiveness in classifying ornamental plants based on morphological measurements. The confusion matrix is presented in Figure 4.  
Figure 4: Confusion matrix obtained with the test dataset for the classification of ornamental pepper plants when using tabular data with morphological measurements and an XGBoost model when classifying based on the median of experts.  
\begin{table}
\begin{tabular}{l l} \hline
**Parameter** & **Value** \\ \hline Input resolution & 600 \(\times\) 400 px \\ Patch size & 20 \(\times\) 20 px \\ Patch grid & 30 \(\times\) 20 (600 total) \\ Embedding dimension (dim) & 128 \\ Sequence length (seq\_len) & 601 (600 + class token) \\ Transformer layers (depth) & 12 \\ Attention heads (heads) & 8 \\ Linformer projection dim (k) & 64 \\ Input channels & 3 (RGB) \\ Output classes & 2 (binary) \\ \hline \end{tabular}
\end{table}
Table 5: Vision Transformer (ViT) configuration for 600 \(\times\) 400 px images.  
The precision, recall, and F1-score values were all 92.86%, indicating balanced performance in terms of both false positives and false negatives.  
Feature importance analysis (Figure 5) revealed that plant height (PH) and plant height to canopy diameter ratio (PH/CD) were the most significant contributors to the decision-making process of the model, followed by largest diameter (D) and leaf density (LD). This highlights that a simpler model can be used using only these features to obtain very similar accuracy.
# A Short-Circuit Current Calculation Model for Renewable Power Plants Considering Internal Topology
###### Abstract  
With the large-scale integration of renewable energy into the grid, traditional short-circuit current (SCC) calculation methods for synchronous generators are no longer applicable to inverter-based non-synchronous machine sources (N-SMSs). Current SCC calculation methods for N-SMSs often use a single-machine multiplication method, which tends to overlook the internal variability of N-SMSs within power plants, leading to low calculation accuracy. To address this issue, this paper first derives an analytical expression for SCC in grid-connected inverters under low voltage ride through (LVRT) control strategies. Then, a single-machine steady-state SCC calculation model is proposed. Based on the classification of N-SMSs, a practical SCC calculation model for renewable power plants is introduced, balancing accuracy and computational speed. The feasibility of the model is validated through simulations. The proposed method enables simple calculations to obtain the steady-state voltage and SCC at the machine terminal, offering strong engineering practicality.  
low voltage ride through; short-circuit current; inverter; renewable power plants; non-synchronous machine sources +
Footnote †: journal: Applied sciences  
0000-0002-1410-745
## 3 Satellite-Borne GPS Data Quality Analysis
### Satellite Visibility  
Satellite visibility refers to the count of satellites tracked by the receiver during a specific epoch, and it serves as an indicator of the receiver's ability to track GPS satellites effectively. In the precise orbit determination process, having a greater number of observations can enhance the accuracy of the parameters being estimated. When more satellites are observed, it provides additional redundant observations, thereby further improving the accuracy of the solution.  
The satellite-borne GPS data from the HY-2B and HY-2C satellites in 2020 DOY349-355 and HY-2D satellite in 2021 DOY263-269 were used for experimental analysis. Figure 4 illustrates the distribution characteristics of the number of satellites observed by the receiver. Notably, 99.7% of the epoch can observe four or more satellites, while 95.5% of the epoch enabled the observation of five or more satellites. Moreover, in 73.4% of the epoch, six or more satellites were observed. In contrast, only 0.3% of the epoch had fewer than four satellites observed. A majority of the available satellites during these observations fell within the range of 5 to 8 satellites. These findings underscore that the \"HY2_Receiver\" is fully capable of meeting the requirements for high-precision orbit determination and exhibits reliable and stable performance.  
The HY-2B/2C/2D satellite-borne GPS observation data encompass five data types: C1C, C1P, C2P, L1C, and L2P. The number and percentage of missing data for each data type during the experiment (sampling rate 1 s) were counted. From Table 2, it can be found that the missing amount of C1C, C1P, and L1C observational data in L1 band is significantly less than that of C2P and L2P observational data in L2 band. This indicates that the \"HY2_Receiver\" can receive the L1 band signal better.  
Figure 4: Number of single epoch observation satellites.  
Figure 3: Change in F10.7 values.
# Energy Optimization in Cluster-Based Routing Protocols for Large-Area Wireless Sensor Networks
## Appendix A Derivation of Effective Area \(A(r,R)\)  
In this appendix, we outline the derivation of Equation (4), the _effective area_. First, in the case of \(0<r<R-L\), the sensor field is totally included in the transmission range, and the effective area is the area of sensor field itself, \(\pi L^{2}\). Second, if we have \(R-L<r<L\), then the two circles of transmission range and sensor field are partially overlapped. In this case, the effective area is the intersection area, \(I(r,R)\), of the two circles, as explained in the remainder of this appendix.  
As in Figure 10(a), let \(C_{1}\) and \(C_{2}\) be the two circles of radii \(R\) and \(L\), respectively, whose centers are at a distance \(r\) (\(R-L<r<L\)) from each other. In this appendix, we temporarily use a Cartesian coordinate system with origin at the center of circle \(C_{1}\) with \(R\) such that the center of \(C_{2}\) with \(L\) is at \((r,0)\), as in Figure 10(a).  
The circles \(C_{1}\) and \(C_{2}\) are described by the following equations, respectively:  
\[x^{2}+y^{2} = R^{2}\] (A1) \[(x-r)^{2}+y^{2} = L^{2}.\] (A2)  
Using Equation (A11) on Equation (A9) yields  
\[A_{1} = \frac{R^{2}}{2}\left(\frac{\pi}{2}-\frac{d_{1}}{R}\sqrt{1-\left( \frac{d_{1}}{R}\right)^{2}}-\sin^{-1}\left(\frac{d_{1}}{R}\right)\right)\] (A12) \[= \frac{R^{2}}{2}\left(\cos^{-1}\left(\frac{d_{1}}{R}\right)-\frac{ d_{1}}{R}\sqrt{1-\left(\frac{d_{1}}{R}\right)^{2}}\right)\] \[= \frac{R^{2}}{2}\cos^{-1}\left(\frac{d_{1}}{R}\right)-\frac{d_{1}} {2}\sqrt{R^{2}-d_{1}^{2}}.\]  
where we used the fact that \(\pi/2-\sin^{-1}(\alpha)=\cos^{-1}(\alpha)\) for any \(\alpha\) in \([-1,1]\). As discussed above, we can now obtain \(A_{2}\) directly by doing the substitutions \(d_{1}\to d_{2}\) and \(R\to L\) on the expression for \(A_{1}\) on Equation (A12)  
\[A_{2}=L^{2}\cos^{-1}\left(\frac{d_{2}}{L}\right)-d_{2}\sqrt{L^{2}-d_{2}^{2}}.\] (A13)  
Finally, intersection area \(I(r,R)\) is computed as twice of the sum of \(A_{1}\) and \(A_{2}\)  
\[I(r,R) = 2(A_{1}+A_{2})\] (A14) \[= R^{2}\cos^{-1}\left(\frac{d_{1}}{R}\right)-d_{1}\sqrt{R^{2}-d_{1} ^{2}}+L^{2}\cos^{-1}\left(\frac{d_{2}}{L}\right)-d_{2}\sqrt{L^{2}-d_{2}^{2}}.\]  
By using Equations (A4) and (A5), we have  
\[I(r,R)=R^{2}\cos^{-1}\left(\frac{r^{2}+R^{2}-L^{2}}{2 rR}\right)+L^{2}\cos^{-1 }\left(\frac{r^{2}+L^{2}-R^{2}}{2 rL}\right)-\tfrac{1}{2}\sqrt{4r^{2}L^{2}-(r^ {2}-R^{2}+L^{2})^{2}}.\] (A15)
# Camera Path Generation for Triangular Mesh Using Toroidal Patches
## 2 Related Work
[19] proposed an approach to discretely approximate differential geometry data using a triangular mesh's structural and morphological information. [PERSON] et al. [20] utilized a statistical approach to estimate the curvature of surfaces, resulting in superior accuracy to previous methods. [PERSON] et al. [21] exclusively used the triangle's normal vector to estimate curvature, achieving results similar to traditional methods. [PERSON] and [PERSON] [15] developed a more precise and efficient method for approximating the principal direction using a second-order surface-fitting method. [PERSON] and [PERSON] [22] proposed a method for estimating curvature using the Hermite radial basis function based on the surface-fitting method. Additionally, there has been an increase in research efforts to integrate this differential geometry into various mesh algorithms [23; 24; 25; 26; 27]. Several researchers utilized toroidal patches to address complex geometric challenges [28; 29; 30]. [PERSON] et al. [28] developed a hybrid bounding volume hierarchy (BVH) for freeform surfaces, employing a rectangle-swept sphere (RSS) at internal nodes and a second-order toroidal patch at leaf nodes to calculate an intersection curve between two freeform surfaces. In a follow-up study, [PERSON] et al. [29] introduced an innovative approach optimized for the efficient computation of self-intersecting curve(s) on a freeform surface. This method utilizes a ternary-structured BVH that incorporates toroidal patches to share relevant data, unlike the conventional binary-structured BVH. [PERSON] et al. [30] employed toroidal patches to compute the Hausdorff distance between two freeform surfaces. [PERSON] et al. [16] introduced a new spatial data structure that integrates toroidal patches with a triangular mesh. This paper proposes a novel method for generating an optimal camera path to observe triangular meshes, building on previous approaches. Our method bridges the gap between traditional path generation techniques and advanced geometric analysis by utilizing the toroidal patch-based spatial data structure [16].
# Watermarking Protocols: A Short Guide for Beginners
## 2 Requirements
### Usability Requirements
#### 2.1.2 Content Provider Problem  
Initially, content providers were web entities specialized in producing and distributing paid digital contents. However, in the last few years, the rise of social networks has turned many common web users into actual content producers wanting to distribute their creations on the Internet. Such users have no skills to protect and distribute their contents, and so they have to resort to specific web entities to implement such functions. They are not different from professional content producers that do not want to directly protect and/or distribute their contents. As a consequence, watermarking protocols have to be designed so as to enable such new categories of content providers to outsource the burdensome activities of digital content protection and distribution according to the new web service models characterizing the current Internet. In fact, the need to involve web entities different from buyers and content providers, such as, for example, cloud computing platforms, poses further security problems for watermarking protocols, since such entities have to be considered \"honest-but-curious\", with all that this entails [10; 11; 12; 13; 14].
## 4 Conclusions  
A magnetorheological (MR) elastomer-based isolated structure has been modeled, and the response investigated for historical near-fault and far-fault earthquake time histories. The stiffness of the isolation layer was controlled utilizing the linear quadratic regulator (LQR) optimal control algorithm. The following conclusions can be drawn after analyzing the simulation results:  
* MRE BIS shows superior performance in the reduction of all three responses evaluated for all the near-field earthquakes compared to the passively isolated structure. Similarly, displacements, storey drifts, and structural accelerations have been reduced significantly compared to the fixed base structure.
* MRE BIS shows superior performance in the reduction of displacement response for all the far-field earthquakes compared to passive BIS. Similarly, relative displacements, storey drifts, and structural accelerations have been reduced significantly compared to the fixed base system.
* Apart from the Kocaeli (FF) excitation time history, MRE BIS shows significantly better performance in the reduction of storey drift and acceleration responses compared to passive BIS for all far-field earthquake excitations. The reasons have been discussed in detail in Section 3. This response may improve the application of a different control algorithm on the structure.
* The response improvement of MRE BIS for all the three responses of displacement, storey drifts, and acceleration is greater for near-fault earthquakes compared to far-fault earthquake records for all the earthquake cases considered.  
M.A.T. (Formal analysis, Investigation, Writing-original draft): M.U. (Conceptualization, Methodology, Supervision, Writing-review & editing, Funding acquisition; S.H.F. (Validation, Supervision); I.U. (Formal analysis); A.H. (Visualization, Writing-review & editing, Project administration). All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.
# Citywide Cellular Traffic Prediction Based on a Hybrid Spatiotemporal Network
## 3 Cellular Traffic Prediction Model
### Time Embedding Module  
In the previous data analysis, we can see that time had a strong correlation with communication traffic. To capture the temporal characteristics of the data for better model prediction, we collected Italian holiday information and introduced hours and holidays as external features in the model input. The specific process was as follows.  
* Dividing the time period of the day into 24 segments, representing 24 h, the time attribute of each data was represented by a 24-dimensional one-hot vector (_Hour_of_Day_).
* Holiday (including weekends and Italian festivals) is represented by a one-dimensional vector (_Is_of_Holiday_) and is entered with 0 or 1, 1 indicating that the day is a holiday and 0 indicating that the day is a working day.  
The above two vectors were combined into a 25-dimensional vector \(T\). For example, if the predicted time point is 12:00:00 11/01/2013 (Italian holiday), the two time data _Is_of_Holiday_ (1) and _Hour_of_Day_ (a 24-dimensional one-hot vector, its 12 th bit is 1) are extracted to form a time feature  
Figure 7: Improved structure of DenseBlock.  
vector \(T\). The feature vector \(T\) is input to the two layer fully connected layer, and the output is an \(H\times W\) dimensional vector \(v_{time}\). The vector is reshaped into a matrix \(M_{time}\) of \(H\times W\) in size through a reshape layer and merged with the input result of the prediction branch. The reshape layer receives a vector of length \(H\times W\) and shapes it into a matrix of \(H\times W\). The calculation process is as follows:  
\[v_{\text{time}}=\sigma\left(W_{\text{time}}^{2}\sigma\left(W_{\text{time}}^{1}T+ b_{\text{time}}^{1}\right)+b_{\text{time}}^{2}\right) \tag{5}\]  
where \(W_{\text{time}}^{i}\) and \(b_{\text{time}}^{i}\) are the learnable parameters of the ith fully connected layer. \(\sigma\) represents the sigmoid activation function.  
\[M_{time}=\text{Reshape}\left(v_{\text{time}}\right) \tag{6}\]  
where \(v_{\text{time}}\in R^{HW\times 1}\) and \(M_{time}\in R^{H\times W}\).
# DisA Limits RecG Activities at Stalled or Reversed Replication Forks
## 3 Results
### DisA Inhibits RecG-Mediated Fork Restoration  
A HJ structure is processed by RecG, leading to a resetting of the nascent strands back to their original configuration (fork restoration) (Figure 2, lanes 2-3), as earlier described for RecG\({}_{E\alpha}\)[10; 11; 34; 56]. Thus, we tested whether this activity is likewise affected by DisA.  
In the presence of ATP (5 mM), DisA did not restore a reversed fork (Figure 3E, lanes 9-11), whereas RecG (15 nM) catalyzed dissociation of \(\sim\)73% of a mobile HJ structure (HJ-J4 DNA) to produce two flayed duplexes that co-migrate (Figure 3E, lane 1).  
When RecG was pre-incubated with HJ-J4 DNA, and then a limiting DisA concentration and ATP were added, the dissociation of HJ-J4 DNA was slightly, but not significantly, increased (\(p>0.1\)) (Figure 3E, lane 2). When higher DisA concentrations were used, the dissociation of HJ-J4 DNA was only slightly reduced, \(\sim\)1.3-fold even at a 3.2:1 DisA:RecG ratios (Figure 3E, lanes 3-4 and 3F grey bars). Conversely, when the HJ-J4 DNA was pre-incubated with increasing DisA concentrations and then RecG and ATP were added, the dissociating activity of HJ DNA was reduced at about stoichiometric concentrations, but strongly inhibited at a 3.2:1 DisA:RecG ratios (\(p<0.01\)) (Figure 3E, lanes 5-7 and 3F empty bars). We can envision that DisA binds to the reversed replication fork and counteracts the unwinding by the RecG translocase. Alternatively, DisA binds to stalled or reversed forks and impedes strand separation by any helicase, acting as a strong protein block.  
To test whether DisA bound to stalled or reversed forks impedes strand separation by any other DNA helicase [see 57], the PcrA DNA helicase was tested. Since PcrA does not branch migrate HJ structures (B.C. unpublished results), we extended the nascent leading-strand (3'tail HJ DNA substrate) or lagging-strand (5 '-tail HJ DNA) of the HJ to provide an entry site for PcrA (Supplementary Figure S3A). As previously described, PcrA preferentially unwinds a 3 'tailed DNA substrate [57]. In the presence of increasing DisA concentrations (12.5 to 100 nM), the helicase activity of PcrA (15 nM) over both DNA substrates did not significantly vary (\(p>0.1\)) even at a 6.6:1 DisA:PcrA stoichiometry (Supplementary Figure S3A). Since at these DisA concentrations all the HJ DNA should be bound by DisA (see Figure 1B), but this does not inhibit PcrA unwinding activity, it is likely that DisA inhibition of RecG processing of reversed forks is specific.
## 8 Future Perspectives  
The MASSIVE project led to the definition of an air-interface suited for the user uplink with GEO Ku- and Ka-band and LEO scenarios. In particular, the robustness of the air-interface defined in MASSIVE allows the possibility to operate low traffic and low duty cycle terminals with low gain flat (e.g., patch array) antennas with Ku and Ka band GEOsatellites. Such air-interface, named IURA (IoT Universal Radio Access), is based on the E-SSA adaptation defined in MASSIVE on the return link, which is able to work at very low C/N (below \(-\)20 dB) thanks to the processing gain provided by the high spreading values (up to 256). These values enable the possibility to equip the terminals with small low gain antennas, e.g., an 8 \(\times\) 8 patch array, and still be able to operate in typical GEO Ku and Ka band scenarios. This, combined with the offered data rates, ranging from hundreds of bit/s to some tens of kbit/s with larger flat antennas, and the possibility to manage a very high number of devices which have to sporadically transmit few data packets, makes it suitable to realize a simple and low-cost terminal for satellite IoT and medium data-rate scenarios.  
Conceptualization, M.A., R.A. and N.A.; methodology, R.A.; software, R.A.; validation, A.I. and R.A.; writing--original draft preparation, A.I.; writing--review and editing, R.A. and N.A.; supervision, N.A. and M.A.; project administration, A.I. and N.A.; funding acquisition, M.A., A.I. and N.A. All authors have read and agreed to the published version of the manuscript.  
This work has been partly supported by the European Space Agency under the procurement Contract no. 4000121226/17/UK/AD.  
Not applicable.  
The authors would like to thank [PERSON], [PERSON] and [PERSON] who was affiliated with Airbus Italia at the time of the MASSIVE project being carried out and who actively participated in the project activities. The authors would also like to thank [PERSON] from ESA for his contribution during the project. Opinions, interpretations, recommendations and conclusions expressed herein are those of the authors and are not necessarily endorsed by the European Space Agency.  
The authors declare no conflict of interest.
## 4 Performance Evaluation
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Handover Approach** & \begin{tabular}{c} **Average Number of** \\ **Handovers** \\ \end{tabular} & \begin{tabular}{c} **Ping-Pong Rate** \\ **(\%)** \\ \end{tabular} & \begin{tabular}{c} **Handover** \\ **Failure Rate (\%)** \\ \end{tabular} & \begin{tabular}{c} **Computational** \\ **Complexity** \\ \end{tabular} & **Key Features** \\ \hline RBH & High & High & High & \(O(N)\) & \begin{tabular}{c} _RSRP_, frequent \\ handovers due to \\ satellite mobility \\ \end{tabular} \\ \hline LBH & Medium & Medium & Medium & \(O(N)\) & \
\begin{tabular}{c} Use UE location, \\ reduces \\ unnecessary \\ handovers but \\ lacks dynamic \\ optimization \\ \end{tabular} \\ \hline Proposed LBH-PRL & Low & Low & Low & \(O(NM+A)\) &
\begin{tabular}{c} Integrates particle \\ filter for distance \\ estimation and RL \\ for adaptive \\ optimization \\ \end{tabular} \\ \hline \end{tabular}
\end{table} 
Table 2: Summary of performance comparison.
# A Blockchain-Assisted Security Protocol for Group Handover of MTC Devices in 5G Wireless Networks
## 2 Related Work
[15] proposes a pre-handover authentication mechanism based on the Chinese Remainder Theorem (CRT), allowing user terminals to achieve rapid handover authentication and key negotiation with the target access relay node. However, it is only applicable to fixed trajectory communication in high-speed rail contexts. Ref. [16] produces a group MTCD handover authentication using base stations installed on drones. It applies to extremely specific scenarios and is not suitable for general use. At the same time, there is also the issue of drones used as base stations being unable to sustain long-term energy consumption. The solutions in [5; 6; 8; 10; 13; 16] are all susceptible to the risk of DoS attacks. During the aggregation of information, the aggregated information can only be successfully verified if all members are legitimate. Attackers can send false aggregate information and intentionally cause the entire group's verification to fail. Ref. [17] presents a secure and privacy-preserving handover scheme for 5G networks, but it comes with higher computational costs due to the use of multiple modular exponentiation algorithms. The development of 5G networks has facilitated the support for large-scale connections of MTC devices, offering higher data rates, lower latency, greater connection capacity, and higher energy efficiency. The introduction of large-scale MTC devices enables tens of thousands of devices to be interconnected, which is crucial for applications such as smart cities, smart homes, and industrial automation that require many sensors and actuators to seamlessly connect and communicate. Existing solutions for large-scale MTCD handover authentication in 5G networks have certain security flaws and are almost ineffective in mitigating DoS or DDoS attacks. Moreover, secure functions like bilinear mapping can lead to high computational overheads. All the abovementioned facts motivate us to design a blockchain-assisted group handover authentication protocol to provide sufficient attack prevention, energy efficiency, and fast computation, making it a piece of significant research work. By the BSPGH scheme, the distributed nature of blockchain is utilized to directly achieve mutual authentication between large-scale MTC devices and the target base station, effectively alleviating DoS or DDoS attacks, while also solving the key escrow problem. In terms of resource consumption, the proposed group handover authentication scheme can reduce signaling costs and authentication costs. Our future research will integrate blockchain technology with future communication network standards and protocols to design lightweight protocols.