esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Results and Discussion
### Comparison of the ORC\({}_{\text{CTE}}\) System and ORC\({}_{\text{DTE}}\) System
The net power output of the ORC\({}_{\text{DTE}}\) system only decreased by 2.68 kW over the investigated ambient temperature. The reason is that the amount of the decrement of net power output reduces due to the increasing turbine efficiency. It can also be found that the net power output of the ORC\({}_{\text{CTE}}\) is higher than that of the ORC\({}_{\text{DTE}}\) system, and the difference shrinks with the increasing ambient temperature. In conclusion, with the increasing heat source temperature, the deviation between the predicted turbine efficiency and the constant turbine efficiency increases. Thus, the error in the theoretical analysis results (including optimal operating parameter determination and performance indicator calculation) caused by assuming the constant turbine efficiency, becomes larger. However, with the increasing ambient temperature, the deviation between the predicted turbine efficiency and the constant turbine efficiency gradually decreases. As a result, the error in the theoretical analysis results caused by assuming the constant turbine efficiency decreases. Figure 8:0 Optimal condensation temperature at different ambient temperature. Figure 8:1 Optimal evaporation temperature at different ambient temperature.
## 2 Modular Multifunctional Approach Advantages
### The Amplitude of the Payload Design Space
However, it is unusual for the 6U, for example, to have payloads whose thickness is under 10 mm, and thus the design space amplitude could be more comparable with the 3U form factor. For smaller form factors (like 1U and 2U) it can be noticed that, although they are disadvantaged from the payload design space amplitude side, they tend to reach significant fractions of the maximum design space amplitude with fewer tiles. For example, in the case of a payload thickness of 6.5 mm and three tiles, the 1U reaches 19.44% of the maximum payload design space amplitude, while the 2U reaches just 0.02%. Significant fractions of the maximum amplitude can be reached with a remarkably major number of tiles, with respect to smaller form factors. An elevated number of tiles would have the disadvantages discussed above, making the smart tiles approach less effective. This again suggests that the smart tiles approach could be more effective with the smaller form factors, like 1U and 2U. Figure 5: Complete results for the 1U, 2U, 3U, and 6U cases: (a) CubeSat volumetric increment \(\delta_{CS}\) as a function of total CubeSat volume \(V_{CS}\) and number of tiles \(k\); (b) specific design space amplitude \(A^{*}\) as a function of total CubeSat volume and payload modules thickness \(t_{payl}\).
# 2D-Unitary ESPRIT Based Multi-Target Joint Range and Velocity Estimation Algorithm for FMCW Radar
## 4 Simulations and Analysis
### Comparison of Estimation Accuracy in the Single-Target Scenario  
In this simulation, we compare the estimation accuracy of various algorithms for targets with different ranges and velocities.  
Figure 3a,b show the RMSE of the range and velocity estimates of various algorithms versus SNR when \(R_{0}=11\) m and \(v_{0}=5.8\) m/s in a single-target scenario, respectively. As can be seen, the RMSE of the proposed algorithm and the MMEMP algorithm almost coincide and are smaller than the other algorithms. The RMSE of the 2D-FFT algorithm tends to be stable due to the fence effect. The RMSE of the 2D-RootMUSIC algorithm increases rapidly when the SNR decreases as it is sensitive to the noise. The RMSE of the 2D-CZT algorithm is lower than the 2D-FFT algorithm and the 2D-RootMUSIC algorithm, but still larger than the proposed algorithm and the MMEMP algorithm. Tables 2 and 3 show the RMSE values of the range and velocity estimates of various algorithms for targets with different ranges and velocities when SNR = 10 dB and SNR = \(-10\) dB, respectively. As can be seen, the RMSE for different ranges and velocities (including positive and negative velocities) estimates of the proposed algorithm and the MMEMP algorithm are smaller than the other algorithms when SNR = 10 dB and SNR = \(-10\) dB. Therefore, the proposed algorithm and the MMEMP algorithm have similar performance and outperform the other algorithms in terms of range and velocity estimation accuracy in the single target scenario.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Values** \\ \hline Sampling rate \(f_{s}\)/kHz & 813.16 \\ Sampling points \(N\) & 256 \\ Number of linear frequency modulation \(M\) & 32 \\ Carrier frequency \(f_{0}\)/GHz & 23.8 \\ Bandwidth \(B\)/MHz & 200.47055 \\ Linear FM period \(T_{l}\)/ms & 0.31482 \\ Speed of electromagnetic waves \(c\)/(km/s) & 299,709 \\ Fast time domain spatial smoothing length \(N_{s}\) & 128 \\ Slow time domain spatial smoothing length \(M_{s}\) & 16 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Simulation parameters.  
Figure 3: RMSE of range and velocity estimates of various algorithms versus SNR in a single-target scenario. (**a**) RMSE of range estimation versus SNR. (**b**) RMSE of velocity estimation versus SNR.
# Optimization of Associative Knowledge Graph Using TF-IDF Based Ranking Score
###### Abstract  
This study proposes the optimization method of the associative knowledge graph using TF-IDF based ranking scores. The proposed method calculates TF-IDF weights in all documents and generates term ranking. Based on the terms with high scores from TF-IDF based ranking, optimized transactions are generated. News data are first collected through crawling and then are converted into a corpus through preprocessing. Unnecessary data are removed through preprocessing including lowercase conversion, removal of punctuation marks and stop words. In the document term matrix, words are extracted and then transactions are generated. In the data cleaning process, the Apriori algorithm is applied to generate association rules and make a knowledge graph. To optimize the generated knowledge graph, the proposed method utilizes TF-IDF based ranking scores to remove terms with low scores and recreate transactions. Based on the result, the association rule algorithm is applied to create an optimized knowledge model. The performance is evaluated in rule generation speed and usefulness of association rules. The association rule generation speed of the proposed method is about 22 seconds faster. And the lift value of the proposed method for usefulness is about 0.43 to 2.51 higher than that of each one of conventional association rule algorithms.  
Keywords:TF-IDF; association rule; apriori; FP-tree; associative knowledge graph +
Footnote †: journal: Applied Sciences
# Routing Protocols for Delay Tolerant Networks:
## 1 Introduction  
In the Internet of Things era, every one of over a trillion everyday items will include at least some ability to store and process information; additionally, and more importantly, sharing that information over the global Internet with the other trillion items. The technological goal is to integrate the Internet and the web with everyday objects (such as doors, chairs, electric appliances, cars, _etc._) and ultimately interconnect the digital and physical domains. Clearly, the types of objects to be connected with the Internet, e.g., in terms of usage, size and numbers, is extremely diverse, thus having different computation and communication requirements. For this reason, a large number of computing architectures and networking paradigms have been proposed, and different networking standards have been developed.  
In most cases, the operational and performance characteristics of the newly-introduced technologies make conventional (Internet-like) networking approaches either unworkable or impractical. Concepts of occasionally-connected networks have become a very common approach for a very diverse range of real-world applications; real-world cases that suffer from frequent partitions and that rely on more than one divergent set of protocols or protocol families. The dominant approach of networking in such cases is to provide the nodes with significant memory capabilities, so that messages can be stored for long periods of time. Whenever communication is established, the stored messages are opportunistically forwarded to the connecting node.  
Almost a decade ago, [PERSON] _et al_. [1] proposed an architecture, using the term \"Delay-Tolerant Networks (DTN)\", that utilized asynchronous message forwarding to achieves interoperability between various types of DTNs. Since then, the Internet Research Task Force (IRTF) established the DTN Research Group (DTNRG) [2], in an attempt to standardize the architecture in RFC4848 [3] and to introduce a communication protocol called the Bundle Protocol (described in RFC5050 [4]) that lies on top of the transport layer, to support interoperability between heterogeneous networks, intermittent connectivity, long or variable delay for DTNs.  
Since then many different protocols have been proposed in order to establish efficient communication among the nodes of the networks [5]. The DTN architecture has been used in a variety of real-world pilot applications, including mobile sensor networks for pervasive information gathering [6], human-centric sensing networks, where nodes are carried by humans [7, 8], networks comprised of ferry boats, where nodes are positioned in sea vessels moving along predefined routes over large geographic regions [9], and inter-planetary networks, designed to withstand the noise and delays incurred by communication across astronomical distances, to account for the occlusion of satellites and planned communication windows [10]. In [11], a number of applications of DTN protocols in urban pervasive use cases is presented.
# Time-Dependent Vehicle Routing Problem with Drones Under Vehicle Restricted Zones and No-Fly Zones
## 5 Algorithm Design and Implementation
### Genetic Operations  
#### 5.3.1 Fitness Calculation  
The fitness function is defined as the reciprocal of the objective function, as illustrated in Constraint (41).  
\[f_{i}=\frac{1}{C_{i}} \tag{41}\]
## 3 Results and Discussion  
### Stratigraphic Description  
Pits revealed the presence of dry, cemented, whitish and clayey material on the soil surface. The stratigraphic description was made according to [PERSON]'s soil classification [19]. The results show a sequence of predominant strata of silty sands with gravel, except for pits three and seven, where the sands showed light brown, whitish cemented clay of evaporitic origin. Sampling points indicate the presence of 7-25% gravel particles; 64-72% coarse-to-fine grain sands, mainly middle sized; and 16% fine low plasticity grain. Middle-to-firm cementation was found in the upper strata and humidity in the lower strata of alluvial-colluvial origin. The results obtained from soluble salts show a 1.12% mean, with pit three presenting the highest value (3.2%). These results are complemented by the results obtained by [PERSON] et al. [20], who reported that the soil is mainly formed by albite (NaAlSi\({}_{3}\)O\({}_{8}\)), anorthite (CaAl\({}_{2}\)Si\({}_{2}\)O\({}_{8}\)), gypsum (CaSO 4\(\cdot\)2H\({}_{2}\)O), quartz (SiO\({}_{2}\)), and orthoclase (KAlSi\({}_{3}\)O\({}_{8}\)), among others. The results also indicate a similarity between the chemical composition of the material deposited on the PV modules and the soil, but showed no significant changes.  
The results obtained from the pits are comparable to those reported in previous studies, where the presence of gypsum is documented as a soluble material, which is essential  
Figure 1: Solar Platform location in Atacama Desert. (**a**) Image taken from MODIS TERRA space instrument, 16 March 2021; (**b**) Pits at PSDA and its surroundings.  
for the cementation processes taking place on the site [18]. Additionally, pit analyses indicate middle-to-firm soil cementation, influencing the amount of material that can be aero-transported by the wind to be deposited on the PV module surface. Previous research reveals that the amount of material deposited on a PV module surface does not exceed 0.05 mg/cm\({}^{2}\) in one month of exposure [6], as compared with 0.2 mg/cm\({}^{2}\) in Kathmandu [21], or 1% daily output power loss in Dhaka [22]. These geological characteristics make the place attractive for the type of soil, which allows for low soiling levels in a desert zone, thus meaning that the site geology plays a positive role.  
There is a similarity between the site geology and the material deposited on the PV modules. Figure 2a shows the geology of the soil in the presence of whitish cemented surface salt, as indicated by the pit results. Figure 2b, corresponding to pit five, shows the presence of white cemented salt at the pit edge. Figure 2c shows a soiled PV module on the site, where crusted clay deposition can be observed, the lower part of the module concentrating the greatest amount of crusted material due to condensed humidity and the slope angle [13; 23; 24]. This comparison helps to understand the geological importance of the site, since it provides relevant data on the PV module soiling formation.
## 3 Implementation and Results
### Envisat
#### 3.1.3 Case 2: Maneuver Detection Threshold Reduced to 0.5-Sigma Relative to Baseline 1-Sigma Case  
Figure 5 demonstrates the consequence of decreasing the maneuver detection parameter to 0.5-sigma from 1-sigma, which resulted in the algorithm detecting five of the nine maneuvers but also six new false maneuvers. This result was also expected because decreasing the maneuver detection threshold affects the amount of false detection. Similar to the case study of TOPEX, these three cases illustrate the sensitivity between the maneuver detection threshold and maneuver detection performance.  
Figure 4: Case 1: Maneuver detection threshold magnified to 2-sigma relative to baseline 1-sigma case. Vertical green lines represent the maneuvers and the red circles represent potential maneuvers detected by this method.  
Figure 5: Case 2: Maneuver detection threshold reduced to 0.5-sigma relative to baseline 1-sigma case. Vertical green lines represent the maneuvers and the red circles represent potential maneuvers detected by this method.  
1.4 Case 3: Window Length Decreased by a Factor of Four Relative to Baseline Case with Detection Limit 0.5-Sigma  
Figure 6 depicts the consequence of reducing the window length by a factor of four, with reference to the baseline case from 45 data points (approximately 45 days in time units) to 12 data points (approximately 12 days in time units). Given this reduction, three of the nine maneuvers, which were observed in the first case, were undetected, and 15 new false maneuvers were detected. This result is due to a decrease in the window length pushing the three cases outside of the 10-day detection threshold.  
1.5 Case 4: Window Increased by a Factor of Two Relative to Baseline Case with Detection Limit 0.5-Sigma  
Figure 7 depicts the consequence of increasing the window length by a factor of two, with reference to the baseline case from 40 data points (approximately 40 days in time units) to 80 data points (approximately 80 days in time units). Given this increase, seven of the nine maneuvers, which were observed in the baseline case, were undetected, and four new false maneuvers were detected, resulting from the noisier data.
## 3 Analysis of TEE Usage in Edge Intelligence and IoT
### Arm TrustZone and CCA  
In 2004, Arm TrustZone was proposed by incorporating hardware security extensions into Arm Cortex-A application processors. Arm TrustZone divides a system's hardware and software resources into two distinct worlds: the Secure World and the Normal World. The Secure World handles sensitive operations, such as cryptographic key management, authentication, and secure storage, while the Normal World runs the standard operating system and applications. The transition between the Secure World and the Normal World is managed through Monitor Mode. TrustZone extends memory security with optional components like the TrustZone Address Space Controller (TZASC) and TrustZone Memory Adapter (TZMA). TZASC manages secure and non-secure memory regions for DRAM, while TZMA handles off-chip ROM or SRAM, enabling secure world access to non-secure areas but not vice versa.  
CCA, designed to enhance virtual machine protection, introduces the Realm Management Extension (RME) and adds two new worlds: Realm World and Root World. CCA introduces the Realm World to create secure, isolated environments for confidential VMs, completely separating them from other domains, including the host OS, hypervisor, TrustZone, and other realms. CCA uses a Granule Protection Table, an extension to the page table that tracks memory ownership with worlds to maintain separation. The Granule Protection Table is managed by the Monitor in the Root World, which ensures that the hypervisor or OS cannot alter it directly. This Monitor also controls the dynamic allocation of memory across worlds by updating the Granule Protection Table. Additionally, CCA features attestation mechanisms that validate the platform and ensure the integrity of the realms. The low power consumption of the ARM architecture makes it well suited for IoT scenarios. Owing to its wide deployment in mobile and low-end devices, ARM TrustZone and CCA are widely deployed in IoT and edge intelligence scenarios [38; 39; 40].
## 4 Heat Transport Pipeline Damage Probability Model
### Importance Analysis  
The LGBM model, which exhibited the highest evaluation indicators, was used to analyze the importance of the input data utilized by the classifier to predict heat transport pipeline damage probability, as shown in Figure 8. Pipe diameter_log and sensor wire condition_log are variables transformed by applying the logarithm to the raw data. The most important factor for the classifier's predictions was the operator, followed by pipe diameter, sensor wire condition, and pipe function. It is difficult to quantify how much these factors affect damage to heat transport pipelines based solely on the importance values presented. However, because the importance ranking corresponds to the correlation analysis results, it is expected that factors with high importance will be useful in decision-making processes, such as maintenance planning.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Dataset** & **Model** & **Accuracy** & **F2-Score** & **AUC** \\ \hline \multirow{3}{*}{A} & XGB & 0.741 & 0.803 & 0.839 \\  & LGBM & 0.737 & 0.804 & 0.837 \\  & RF & 0.707 & 0.744 & 0.804 \\ \hline \multirow{3}{*}{B} & XGB & 0.753 & 0.776 & 0.862 \\  & LGBM & 0.741 & 0.781 & 0.861 \\  & RF & 0.714 & 0.726 & 0.832 \\ \hline \multirow{3}{*}{C} & XGB & 0.768 & 0.730 & 0.901 \\  & LGBM & 0.770 & 0.740 & 0.900 \\ \cline{1-1}  & RF & 0.730 & 0.721 & 0.891 \\ \hline \end{tabular}
\end{table}
Table 6: Performance of models for predicting heat transport pipeline damage probability.  
Figure 7: ROC curve.
## 4 Conclusions  
In this paper, the simulation and real-time setup of the visual-MIMO communicating system has been developed using a novel QR-Code and particle filter tracking algorithms for SVN. The security aspect of the SVN is addressed by a novel LFSR based key generation technique. The key is generated using a random pixel value based synthetic colour image. This key is used in a stream cipher encryption algorithm to generate ciphertext. The randomness test of the generated key exhibits a probability value greater than 0.01 with the least being 0.122 (\(>\)0.01) in the linearity test. The generated key is of 196,608 bit in size, which makes it robust and complex to predict. This makes the proposed system more secure and an ideal candidate for the visual MIMO communication.  
The LoS requirement of the visual MIMO is achieved by using the QR-code with the particle filter algorithm. A QR-inspired LEA is designed by embedding LED transmitters with the finder and alignment pattern. The robustness of the QR code makes the identification of LEA more reliable. The particle filter is used for tracking and to maintain the LoS. The proposed system is analyzed in the simulation and real-time environment. The performance of the proposed tracking algorithm is analyzed in the presence of the translation, rotation, scaling, and motion blur distortion. The BER and tracking error are considered as performance metrics. Simulation studies are carried out to analyze the performance of the particle filter based tracking. The results illustrate a better performance as compared to a system without the particle filter.  
A prototype of the QR-inspired LEA is fabricated and tested on the real-time environment. ATT has been proposed to compensate the interference generated due to the ambient light and adjacent transmitter elements. The BER performance of the proposed ATT is evaluated in the presence of geometric distortions and results illustrated an average of 53.6% improvement in BER with the use of ATT. Thus, the proposed system is considered as secure and reliable for the visual MIMO communication. The proposed visual MIMO can be extended for a multi-vehicle environment in which the particle can address the associated problem. The use of multi-vehicle communication demands a unique key for each user, and these keys can be generated using the proposed key generation technique.  
**Author Contributions:** All the authors equally participated in the technical discussion, design, implementation, testing, performance measurement, and writing of the article.  
Figure 25: BER performance comparison with and without ATT. (**a**) Without the particle filter (**b**) with the particle filter.  
**Funding:** This research received no external funding.  
**Conflicts of Interest:** The authors declare no conflict of interest.
# Autonomous Pointing Control of a Large Satellite Antenna Subject to Parametric Uncertainty
###### Abstract
Besides, current space missions always require autonomy and intelligence, such as on-orbit identification and intelligent control. That means intelligent control techniques are applied in spacecraft systems, which could make the spacecraft perform on-orbit operations autonomously without the support of the ground station and astronauts. Consequently, it is imperative to take the stability of closed-loop system, parametric uncertainty and pointing errors into consideration simultaneously, and then develop a new intelligent control algorithm to achieve autonomous pointing maneuvers. The adaptive control approach provides an ideal solution to deal with this problem since it can handle online estimation for uncertain and unknown system parameters. To address these challenges, frequency-domain methodology is used to design the autonomous pointing controllers in this paper. The proportional-derivative feedback and structural filter, to perform pointing maneuvers and suppress antenna vibrations, are firstly proposed. A modified adaptive controller, based on above controller and adaptive filter technique is then developed in the presence of modal parameter uncertainty. The active disturbance rejection filter is finally designed and integrated into the closed-loop system. The novelty lies in that the proposed autonomous controller could estimate in orbit, compensate the uncertain modal parameters and decrease the periodic pointing error simultaneously. The proposed control approach can avoid excessive complexity of the control laws, and reduce the dependency of the controller on the knowledge of the system parameters.