esa-sceva/satcom-chunk-collection huggingface dataset:
# LoRaWAN Path Loss Measurements in an Urban Scenario Including Environmental Effects
## 4 Experimental Setup
### End Nodes  
We selected the platform Pycom LoPy4 ([[https://pycom.io/product/lopy4/](https://pycom.io/product/lopy4/)]([https://pycom.io/product/lopy4/](https://pycom.io/product/lopy4/)), accessed on 14 December 2022) to assemble and program the ENs because it meets processing and communications needs; hence, previous approaches use it [20]. The LoPy4 is a system-on-chip platform that embeds an Xtensa(r) dual-core 32-bit LX6 microcontroller and four IoT radios, including LoRaWAN, Sigfox, Wi-Fi, and Bluetooth. Regarding LoRaWAN, the platform includes an SX1276 radio for ISM bands @ 433, 868, and 915 MHz. In addition, the processor can communicate with the environmental sensors by using different buses like serial peripheral interface (SPI), inter-integrated circuit (I2C), and universal asynchronous receiver and transmitter (UART). In addition, each EN has a transmission antenna. EN1, EN2, and EN3 use an omnidirectional antenna (Mobile Mark ref. PSKN3-900 ([[https://www.mobilemark.com/product/pskn3-900-1900s/](https://www.mobilemark.com/product/pskn3-900-1900s/)]([https://www.mobilemark.com/product/pskn3-900-1900s/](https://www.mobilemark.com/product/pskn3-900-1900s/)), accessed on 14 December 2022)) with a peak gain of 3 dBi. Because these antennas are omnidirectional, their mounting angle was considered to be 90\({}^{\circ}\). In addition, the EN4 uses a 4-elements Yagi-Uda antenna ([PERSON] ref. YA6900W ([[https://www.tessco.com/product/890-960](https://www.tessco.com/product/890-960) mhz-8 dbi-4-element-yagi-antenna-57677]([https://www.tessco.com/product/890-960](https://www.tessco.com/product/890-960) mhz-8 dbi-4-element-yagi-antenna-57677), accessed on 14 December 2022)) with a peak gain of 8.8 dBi, which was mounted such that the boom was parallel to the ground, with the directors perpendicular to the ground. Figure 5 depicts the antennas' mounting positions.  
Furthermore, we performed an S11 and S21 analysis of the antennas and connectors by using a vector network analyzer (VNA). In particular, the S11 parameter delivers information on how much power is reflected from the antenna when a transmitter signal is supplied. In that way, this parameter allows designers to know how efficient the used antenna is. In addition, the S21 parameter measures how much power is transferred from  
Figure 4: LoRaWAN deployment to capture the information contained in the dataset.  
Figure 5: Mounting angles of the ENs’ antennas. The omnidirectional antennas were mounted perpendicular to the ground. The Yagi–Uda antenna was mounted with the boom parallel to the ground.  
port 1 to port 2 of the VNA, so it is used to determine attenuations/losses from cables and connectors. Carrying out these measurements guaranteed that the antenna gains and losses were accurate. An example of the S11 parametrization of our antennas is depicted in Figure 6.
# A Secure IoT-Based Irrigation System for Precision Agriculture Using the Expeditious Cipher
## 2 Materials and Methods
### MQTT Security Challenges and Solutions  
MQTT runs over TCP with few security techniques such as simple authorization policies and basic authentication techniques. TLS/SSL with session key management has been suggested for securing MQTT; however, proposed security techniques for MQTT should be lightweight for deployment in IoT environments. TLS/SSL has been proven to have performance issues in terms of processing time, memory required, and energy consumption, in addition to the various possible attacks such as Heartbleed, CRIME, BEAST, and RC4. Furthermore, TLS does not provide fine-grained access control [26]. Moreover, MQTT suffers from several security shortcomings, mainly from a lack of confidentiality, integrity, availability (DOS attack), mutual authentication, access control, control message security, and end-to-end security. In [27], the authors reviewed the symmetric, asymmetric, and hybrid lightweight schemes proposed in the literature for guaranteeing the confidentiality of transmitted data using MQTT. Moreover, the authors' review suggested security techniques for guaranteeing access control in MQTT. According to [28], the security threats against MQTT are mainly replay attacks and man-in-the-middle attacks (MITM). Value-to-keyed-hash message authentication code (Value-to-HMAC) has been deployed to achieve information confidentiality. In [26], the authors designed a security architecture for MQTT-SN to achieve end-to-end security in addition to fine-grained access control. Moreover, they introduced a certificate subject to create a secure direct channel between a publisher and a set of subscribers. In addition, they designed security schemes to integrate mutual authentication and control message security functions into the standard MQTT-SN control messages, without relying on the TLS. In [20], the authors proposed ChaCha20-Poly1305 Authenticated Encryption with Associated Data (AEAD) as a solution to secure resource-constrained node communication over MQTT/MQTT-SN. RFC 6574 [29] describes constrained nodes as they are bandwidth constrained, energy constrained, and memory constrained. Performance evaluation of the proposed scheme revealed a low memory requirement and low processing time. In [30], the authors presented a lightweight authentication and encryption mechanism based on ECDHE-PSK (Elliptic Curve Diffie-Hellman Ephemeral)-(Pre-Shared Key) for IoT-constrained devices. The proposed security mechanism outperforms the ECDHE-ECDSA in all performance evaluation tests.
## 5 Experimental Results and Analysis of the Prediction Model
### ResNet Comparison of Different Layers  
In this study, preference was given to networks with lower complexity that maintained satisfactory performance, as opposed to more complex ones. To identify the optimal network architecture for the classification task, we compared results across different ResNet variants. Table 5 presents the classification performance of ResNet18, ResNet34, and ResNet50.  
As shown in the table, all three residual networks achieved high accuracy (around 90%). Specifically, ResNet18 yielded the highest accuracy at 93.72%, followed by ResNet34 at 91.76%, with ResNet50 achieving the lowest at 89.67%. This indicates that increasing the number of network layers does not necessarily improve model performance.  
Figure 12 presents the classification and prediction results of transfer learning using ResNet34 and ResNet50. As shown, both residual networks exhibited small prediction errors and low data dispersion. However, individual predictions showed significant deviations--for instance, ResNet50 had a case where the predicted value differed from the actual value by two magnitude units. This suggests that while ResNet34 and ResNet50 (with 34 and 50 layers, respectively) can learn more complex features, their larger parameter counts make them prone to overfitting. Additionally, deeper networks have higher computational costs and require more device memory.  
Thus, the selection of the network depth should be based on the actual microseismic magnitude detection equipment and error tolerance requirements.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Model** & **Accuracy** \\ \hline ResNet18 & 0.9372 \\ ResNet34 & 0.9176 \\ ResNet50 & 0.8967 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Comparison of classification results for ResNet18, ResNet34, and ResNet50.
## 4 Methodology
### Causal Configuration Analysis Using fsQCA
#### Calibration  
The initial step in fsQCA involves transforming variables into \"fuzzy sets\" [49], representing the degree to which each case belongs to a set--the calibration of raw data. These sets are referred to as \"conditions\" (analogous to independent variables in regression) and \"outcome\" (analogous to the dependent variable). By analyzing these fuzzy sets, researchers can identify the combinations of conditions, or \"configurations\", that are sufficient for producing a specific outcome [50]. These configurations, also known as \"causal recipes\", reveal the complex interplay of conditions that lead to the outcome of interest.  
This calibration process involves establishing three thresholds: full membership (1.0), full non-membership (0.0), and a crossover point (0.5) where a case is equally in and out of the set. This is similar to normalizing data [49]. Following [51], we calibrated our variables using a cluster-based approach with Euclidean distance to determine these thresholds.
###### Abstract  
The main goal of this research was to model and optimize the extraction process of bioactive compounds from spent coffee grounds (SCG). This study utilized response surface methodology (RSM) to determine the significance of the effects of independently tested extraction process conditions and their interactions. The quality of the SCG extracts was evaluated by performing the following determinations: total polyphenols content (TPC), ABTS and FRAP assays, browning index (BI), and caffeine and chlorogenic acids contents by high-performance liquid chromatography. The resultant optimal extraction conditions, which maximized recovery of antioxidant bioactive compounds, were 65% hydroethanic solution (\(v/v\)) in a solvent-matrix ratio of 51 mL/g CS, followed by ultrasound-assisted extraction carried out for 30 min at 60 \({}^{\circ}\)C. The SCG extract obtained by this extraction variant had values for TPC, ABTS, FRAP and BI of approximately 38 mg GAE (gallic acid equivalent) per g d.m. SCG, 73 mg Trolox/g d.m. SCG, 81 \(\mu\)mol Fe (II)/g d.m. SCG, and 0.22, respectively. The sample was also characterized by a high content of caffeine (5 mg/g d.m. SCG) and chlorogenic acids (8 mg/g d.m. SCG). Based on the obtained results, SCG may be recognized as a coffee by-product that has abundant components with antioxidant activity and broad possible applications in agri-food processing fields.  
c 2023 by the authors. Liconse MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([[https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/)]([https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/))).
## 7 Conclusions  
This study systematically identifies nine-dimensional characteristic space characterizing Iridium epochs through extensive empirical measurements and positioning experiments with Iridium signals. Building upon this foundation, an innovative Agent-Weighted RLS Positioning Framework (AWR-PF) is proposed, where an agent dynamically adjusts epoch-specific weights in real time based on characteristic variations to enhance positioning accuracy through RLS iterations. Statistical results from 97 independent experiments demonstrate that the AWR-PF achieves superior positioning accuracy compared to standard RLS. Detailed case-by-case analysis further reveals the trained agent's capability to adaptively modulate weights according to variations within the 9D characteristic space, exhibiting remarkable algorithmic robustness. This work represents the first successful integration of AI algorithms as the core decision-maker in LEO SOP positioning, demonstrating promising initial results. Future refinements in modeling, AI training algorithm selection, and hyperparameter optimization will further unlock the potential of the proposed framework.  
Writing--original draft preparation, methodology, and validation, J.Y.; writing--original draft preparation, methodology, and validation, F.L.; conceptualization, original idea, supervision, writing--review, R.L.; writing--review and editing X.C.; investigation, L.Z.; supervision, H.Y.; project administration, G.Y. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the Specialized Research Fund for State Key Laboratory of Solar Activity and Space Weather.  
The raw data supporting the conclusions of this article will be made available by the authors on request.  
This research has no additional acknowledgments for institutions or individuals.  
The authors declare no conflicts of interest.
# An Improved Weighted and Location-Based Clustering Scheme for Flying Ad Hoc Networks
## 5 Performance Evaluation
### Clustering Scheme Comparison
#### 5.3.2 Analysis of UAV Speed  
The performance of IWLC is evaluated and compared with the clustering scheme of WSCA and ACO, by varying the speed of the UAVs. The number of UAVs is 100. As can be observed from Figure 13, the cluster head changing ratio grows, owing to the rapidly changing topology and link instability with the increasing speed of the UAVs, and the cluster head changing ratio of the IWLC scheme was always at the minimum. Since the IWLC considers the weight of the four important parameters comprehensively in the CH selection phase, especially the relative mobility and adaptive node degree of the UAVs, the stability of the CHs is better than other schemes. In addition, the scheme adopts a stable clustering formation and cluster  
management and maintenance. Moreover, the effective cluster maintenance strategy of IWLC scheme reduces the probability of communication link disconnection.
## 2 Results
### Effect of the Type of Stopper and Storage Time on the Phenolic Profile

Table 3: Dissolved oxygen (mg L\({}^{-1}\)). To better understand the influence of storage time and type of stopper on the phenolic profile in relation to dissolved oxygen, PCA was performed with all the phenolic compounds and the dissolved oxygen values obtained at each step of analysis. Rose wines were excluded from the PCA because their content of phenolic compounds was lower than the red wines. The PCA plot showing the loading of variables and the scores of the samples in the bi-dimensional space is reported in Figure 1.  
The first two principal components made up 73% of the model (PC-1 42%, PC-2 31%) when taken together. Samples collected at bottling time (T1), after one month (T2) and after three months (T3) were grouped on the negative side of the PC-1 axis, whereas the wines stored for six months (T4) and 12 months (T5) were placed on the positive side of the PC-1 axis. Considering the loadings, the three classes of phenolic anthocyanins (glucosides, acetyl-glucosides and coumaroyl-glucosides) and non-anthocyanin phenolic compounds, such as syringic acid, showed a positive correlation with Lagrein red samples collected at bottling time (T1), three months (T2) and at six months (T3). On the other hand, catechin and epicatechin showed a good correlation with Santa Madgalener and Merlot samples analyzed at T1, T2 and T3. Gallic acid, protocatechuic acid, GRP, caffeic acid, \(p\)-coumaric and trans-resveratrol were positively correlated with the Merlot and Lagrein samples collected after six months (T4). Caftaric acid characterized all the wines stored for 12 months (T5), as well as the St. Magdalener wines sampled at six months storage (T4). The dissolved oxygen was not strongly correlated with any specific sample. Figure 1: PCA bi-plot (% explained total variance: PC-1, 42%; PC-2, 31%) of the three red wines closed with different stoppers considering the phenolic profiles and the dissolved oxygen (DO\({}_{2}\)) during 12 months of bottle storage. Samples: SC and SSC, St. Magdalener closed with conventional stopper or ’blend’ stopper, respectively. LC, LSC, Lagrein with conventional or ’blend’ stopper, respectively; MC, MSC, Merlot. Storage in bottle: 1, wine just after bottling; 2,3,4,5, wine analyzed one, three, six and 12 months after bottling, respectively. Phenolic compounds: MON, non-acylated anthocyanins; ACE, acetylated anthocyanins; COU, coumaroylated anthocyanins; GA, gallic acid; PR, protocatechuic acid; GRP, glutathioneyl caftaric acid; CA, caftaric acid; CF, caffeic acid; CT, catechin; EC, epicatechin; SY, syringe acid; PC, \(p\)-coumaric acid; RE, resveratrol. This PCA model successfully scattered the samples depending on the storage period, whereas the bottles closed with similar stoppers were not clearly separated in any case. The multivariate approach confirmed the ANOVA results, remarking the dominant influence of the storage time over the type of stopper.
## 4 Parametric Analysis
### Equivalent Bending Stiffness of Pipeline  
According to the pipeline's deformation from Figures 12-15, the pipeline sometimes generates rigid deformation, sometimes flexible deformation. The flexible deformation is the coordinated deformation with the ground. Some previous studies indicated that the deformation mechanism is relative to the equivalent bending stiffness. Figure 16 illustrates the effect of the equivalent bending stiffness on the pipeline's deformation. Smaller equivalent bending stiffness results in coordinated deformation with the ground, whereas a larger one results in rigid deformation.
# Unveiling the Core Patterns of High-Latitude Electron Density Distribution at Swarm Altitude
## Abbreviations  
The following abbreviations are used in this manuscript:  
ACC - Accelerometer  
AE - Auroval Electrojet  
ASM - Absolute Scalar Magnetometer  
EFI - Electric Field Instrument  
EEMD - Ensamble Empirical Mode Decomposition  
EMD - Empirical Mode Decomposition  
ESA - European Space Agency  
EO - Earth Observation  
EUV - Extreme Ultra Violet  
FTE - Flux Transfer Event  
GLONASS - Globalnaya Navigazionnaya Sputnikovaya Sistema  
GNSS - Global Navigation Satellite System  
GPS - Global Positioning System  
GPS Receiver  
IMF - Interplanetary Magnetic Field  
LP - Langmuir Probe  
LRR - Laser Retro-Reflector  
LSTM - Long Short-Term Memory  
MEMD - Multivariate Empirical Mode Decomposition  
MIT - Main Ionospheric Trough  
MLT - Magnetic Local Time  
QD - Quasi-Dipole  
SED - Storm-Enhanced Density  
STR - Star Tracker  
SuperDARN - Super Dual Auroral Radar Network  
TEC - Total Electron Content  
TII - Thermal Ion Imager  
VFM - Vector Field Magnetometer
## 3 Technical Features and Socio-Legal Characteristics of Africa's Satellite Constellation
### The Role of Geospatial Products in Boundary Demarcation Contracts  
Much of the strides made by Nigeria in the Space sector described above happened after the judgment of the World Court. Its satellite infrastructure and has been taking place slowly and piecemeal manner. Thus, there has been very little opportunity to incorporate its growing competence during the implementation stages of the judgment. Other issues that have prevented such desirable justification for Nigeria's investments in space satellites include administrative 'bottle necks,' the disappearance of Nig-CommSAT from space in November, 2008 and the delays in launching of NigSAT-2 initially proposed for 2007 [56]. Perhaps more significantly from an economic point of view, the inability to utilise developing homegrown satellite technological opportunities created the conditions for the prohibitive costs which have become a valid criticism of the Cameroon-Nigeria implementation process. Two surveyors from both countries closely involved in that process persuasively hint at the loss of huge savings by contracting out what could have been done with domestic capabilities. They wrote that, \"... the UN cartographic consultant's Specifications and Technical Guide based on 'international standards' made the cost of the demarcation exercise prohibitive\" [57].  
Typically after states resolve to complete the demarcation of an international boundary a series of commercial geoscientific data based contracts will be awarded. The demarcators would always place reliance on the data acquired and/or retrieved. The Mixed Commission approved the specifications for all the contracts for the demarcation of the boundary and requested that certain key contracts should be announced on the U.N website [58]. The contracts that were announced to international bidders included.  
* (a) Contract for Spot 5 Satellite Imagery mapping;
* (b) Contract for GPS Ground survey Control for Spot 5 imagery;
* (c) Contract for Geodetic Datum Stations Emplacement;
* (d) Contract for Quality Assurance of Geodetic Datum Stations;
* (e) Contract for Boundary pillar emplacement;
* (f) Contract for: As-built Survey of Boundary Pillars [59].  
The Mixed Commission adopted other assignments for other joint technical teams, including the field verification with the contractor for the imagery of the pillar emplacements shown on the ortho-imagery. Pillar designs were then approved for both the geodetic datum stations and for the final demarcation of the boundary. It was upon these precise mix of scientific products and legal contractual mechanisms that the seventeen yearlong processes for the demarcation of approximately 2000 km of land boundaries between the two African states has proceeded.
# Assessing the Sustainability of Alternative Shaft Construction Methods
## 4 Shaft Construction Methods  
### SBE Shift Excavation  
Despite the optimization of the design of the shaft support, which, accordingly with [PERSON] et al. [34], significantly reduced the thickness of the diaphragm wall, the solution adopted for the shaft includes substantial structural elements, with its 1.5 m thick diaphragm wall complemented by the 2.5 \(\times\) 2.5 m\({}^{2}\) concrete ring beam. To evaluate to what extent the adopted support could be reduced, thus potentially leading to more sustainable designs, two additional analyses were performed. In the first one, the ring beam was not modelled (SBE-Ring), while in the second one, in addition to disregarding the ring beam, the thickness of the diaphragm wall was reduced by half to 0.75 m (SBE-0.75).  
Figure 4: Comparison of predicted and observed diaphragm wall deflections at different shaft excavation depths: (**a**) 5.0 m; (**b**) 11.5 m; (**c**) 18.0 m; (**d**) 25.0 m.  
Figure 5 presents, for the last excavation stage (29 m depth), the horizontal movements and forces (in terms of hoop and bending moment envelopes) obtained in the diaphragm wall for the various SBE analyses. The results show that the ring beam has an almost negligible effect, contributing only to a slight reduction in the horizontal displacements at its location. Similarly, only local variation is predicted in terms of structural forces, with a slight increase in both hoop forces and bending moments. In contrast, the reduction in the wall thickness leads to a considerable decrease in the associated bending moments (by a factor of more than 60%) and hoop forces (factor of 15%). However, the reduction in terms of forces is associated with an increase in horizontal movements, which now reach a maximum of 9.5 mm, an increase of 120% compared with the reference analysis (4.3 mm). The influence of reducing the stiffness of the diaphragm wall by half is also noticeable in the estimated settlements at the surface (Figure 6), where an increase of about 45% is observed. Nevertheless, even after such increases, the magnitude of the ground movements induced by excavation of the shaft can still be considered small.
## 3 Proposed Method
### Flow-Based Data Acquisition  
In this approach, the gathered network data is of the communication flow type [25]. It may come from a broad range of devices, e.g., switches, routers and hosts; it features the properties and statistics pertaining to a network in an aggregated manner. As far as the architecture of the flow-enabled devices is concerned, collectors are the elements where the collected traffic is sent. Subsequently, it is stored and kept there for further analysis, which is usually performed as part of auditing activities by network administrators. In a single flow, the following characteristics are collected:  
* the number of incoming and outgoing bytes
* IP addresses partaking in the communication
* utilized source and destination ports
* utilized type of protocol (e.g., transmission control protocol (TCP) or user datagram protocol (UDP))  
Network node anomalous behaviour patterns (parameter changes in network flows) must be identifiable, and this kind of data ought to enable identification, as the patterns can be indicative of malware infection. Thus, a network administrator is able to utilize them in order to recognize an adversary.