esa-sceva/satcom-chunk-collection huggingface dataset:
## 2 Materials and Methods  
### Study Area Description  
The Moulouya basin (Figure 1) is located in the northeastern part of Morocco and covers an area of about 55,000 km\({}^{2}\), according to the Moulouya River Basin Agency (ABHM). The main watercourse of the Moulouya is 600 km long. It takes its sources at the junction of the Middle Atlas massif and the High Atlas and flows northeastward into the Mediterranean at Ras El Ma [32; 49]. Administratively, this basin overlaps, entirely or partially, on the territories of the provinces of Nador, Figuig, Jrada, Oujda-Angad, Berkane, Taourirt, Guerci, Taza, Boulemane, Midelt, and Khenifra, with a total population exceeding 2.5 million inhabitants.  
The water supply of the Moulouya plays an important role in the national agricultural economy [50]. Indeed, according to the Ministry of Agriculture, Maritime Fishing, Rural Development and Water and Forests, the contribution of the first seven provinces, which make up the eastern administrative region, is estimated to be 14% for citrus, 10% for olives, 9% for sugar beets, and 8% for red meat [33; 51].  
The large area and the diversity of the relief of the Moulouya watershed make the climate very variable from one region to another. The climate varies from a Mediterranean type in the lower Moulouya to a relatively cool continental climate in the Upper Moulouya and to arid with Saharan tendencies in the Guercif basin towards the highlands of the Middle Moulouya [32; 49; 52]. Annual rainfall is relatively low and irregular. Annual cumulative rainfall can vary from less than 100 mm to just over 600 mm [53]. Snowfall generally occurs above 1500 m altitude and persists only above 2000 m altitude on the mountain peaks of the Middle and High Atlas and sometimes on the high plateaus.  
Figure 1: Geographical location of the Moulouya watershed.
# Effect of Electrospun Nanofiber Additive on Selected Mechanical Properties of Hardened Cement Paste
###### Abstract  
This study presents an estimation of the mechanical property enhancing mechanism of electrospun-nanofiber-blended cementitious materials. Four types of electrospun nanofibers (NFs) were introduced into Portland cement: nylon 66 nanofibers, tetraethyl orthosilicate/polyvinylpyrrolidone nanofibers (TEOS/PVP), hybrid nanofibers containing carbon nanotubes (CNTs) and nylon 66, and hybrid nanofibers containing carbon nanotubes and TEOS/PVP (CNTs-TEOS/PVP NFs). Due to the mechanical strength results, there was an increase of 27.3% and 33.4% in compressive strength when adding TEOS/PVP nanofibers and the hybrid nanofibers containing carbon nanotubes and TEOS/PVP into the pastes, respectively. In addition, there was an increase of 25.7% and 54.3% in tensile strength when adding nylon 66 nanofibers and the hybrid nanofibers containing carbon nanotubes and nylon 66 into the pastes, respectively. The highest toughness of 61.7% was obtained by the paste blended with CNTs-TEOS/PVP NFs. The results observed from scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis clarified the change in the microstructure of the modified pastes, as well as the mechanical property enhancing mechanism of the electrospun-nanofiber-blended cementitious materials.  
TEOS/PVP nanofibers; nylon 66 nanofibers; cement; electrospinningning; carbon nanotubes; mechanical strength +
Footnote †: journal: Applied Physics Letters  
Article
# Fault Feature Extraction of Parallel-Axis Gearbox Based on IDBO-VMD and t-SNE
## 6 Experimental Verification
### Fault Classification  
The feature vectors of the 200 training samples were input to the SVM classifier for training, resulting in an SVM model for fault diagnosis. Subsequently, the 50 test samples were input into the trained SVM model for classification. In the SVM training and testing, numeric labels were used to represent the five gear operating states: normal state as label 0, tooth root fracture as label 1, surface wear as label 2, surface cracking as label 3, and surface pitting as label 4. The diagnostic accuracy for gear classification can reach 100% using the IDBO-VMD and t-SNE dimensionality reduction feature extraction methods.  
To demonstrate the accuracy of the proposed approach, the same collected data were used, and signal decomposition was performed using three methods: EMD, traditional VMD, and IDBO-VMD. For traditional VMD, the parameter selection was based on the central frequency method, where the final value of K was determined by observing the  
Figure 10: Comparison of three dimensionality reduction methods: (**a**) t-SNE dimensionality reduction effect; (**b**) dimensionality reduction effect; (**c**) PCA dimensionality reduction effect.  
central frequencies of IMF components for different K values [25]. K = 6 and \(\alpha\) = 2000 were confirmed through observation.  
Then, feature extraction and t-SNE dimensionality reduction were carried out, and, finally, the obtained low-dimensional feature distribution and SVM classification accuracy are depicted in Figure 9 and presented in Table 5, respectively.  
According to Figure 11 and Table 5, it is evident that the diagnostic accuracy using the feature extraction method based on IDBO-VMD and t-SNE is slightly higher than the other two methods. Furthermore, the fault features obtained through EMD decomposition and t-SNE dimensionality reduction are effective in separating the four different states, but the clustering effect is suboptimal. From Figure 12, it can be observed that both EMD and traditional VMD exhibit diagnostic errors when diagnosing normal signals, leading to a decrease in accuracy. Therefore, the proposed IDBO-VMD and t-SNE methods, characterized by high accuracy and ease of operation, represent effective approaches for fault diagnosis.
# User Pairing for Delay-Limited NOMA-Based Satellite Networks with Deep Reinforcement Learning
## 1 Introduction
The main contributions of this work can be described as follows:  
* The concept of effective capacity is employed to measure the rate achieved with a given delay QoS constraint, based on which, a power allocation coefficient is firstly obtained by ensuring the achieved capacity of users with sensitive delay QoS requirements is not less than that achieved with an OMA scheme, and then, the user pairing problem is formulated with the aim of maximizing the sum effective capacity of the considered system;
* Because various delay QoS requirements have varying negative impacts on users' capacity, user pairing in a NOMA-based network with various delay QoS constraints is different from that in traditional NOMA-based delay-insensitive system. In this condition, to maximize system capacity with the obtained power allocation factor, when the delay-critical user is fixed, a DRL approach is introduced to select one user who has relatively insensitive delay requirement and good link condition, compared to the other users, to optimize NOMA user pairing with low complexity;
* The proposed DRL-based NOMA user pairing strategy is compared to an OMA scheme and NOMA with a random user-selecting scheme, which reveal the superiority of introducing the NOMA scheme and DRL algorithm in the satellite networks from the perspective of performance enhancement. Specifically, the advantage of the proposed approach is achieved by selecting the most suitable delay tolerant user to pair with the delay-sensitive user and form a NOMA user group in each time slot. The rest of this paper is outlined as follows. The system model is presented in Section 2. Section 3 introduces the concept of effective capacity, obtains the power allocation scheme by ensuring the achieved capacity of the user with sensitive delay QoS requirement is not less than that achieved with the OMA scheme, and formulates the user pairing problem for the delay-limited NOMA-aided satellite network. In Section 4, a DRL algorithm is described in detail and tested in the proposed system. Performance results are discussed and conclusions are given in Sections 5 and 6, respectively.
## 4 Numerical Experiments
### Experiment Results  
As presented in Table 2, the results of the experiments showed that the average relative errors were (a) 1.59%, (b) 2.08%, respectively. The relative error indicates the magnitude of the error compared to the actual length, as illustrated in Equation (4).  
\[Relative\,error=\frac{Absolute\,error}{Actual\,size}=\frac{abs(Actual\,size- estimated\,size)}{Actual\,size} \tag{4}\]  
These results corresponded to errors of 0.79 cm and 1.04 cm, at a length of 50 cm. Compared to the relative error of the manual size measurement (3.25%, value (c) in Table 2), the experimental results showed that it was sufficiently accurate to replace manual measurements in terms of precision. In addition, the standard errors of both experiments were less than 0.0020 (0.20%), indicating that our design of the size measurement was tolerant even if the positions or arrangements of the clothes were slightly different.  
The average relative error was mainly inflated by some sizes with large relative errors (e.g., cuff opening and leg opening in Table A1); there were two main reasons for this. First, when the actual length was small, the relative error was overestimated. This is explained by the fact that the absolute errors were all less than 1 cm regardless of the sizes, except for the front rise in Experiment 2. On the other hand, when the detected measurement point deviated slightly from the position, the error increased proportionately. We observed that at certain points with relatively poor visual features (e.g., points on the back of the neck of a T-shirt, the croch point of shorts and trousers in Table A1), the detection performance also deteriorated. Because the DeepFashion2 dataset [16] contained mostly images of people in clothes, some points were obscured by the human skin. In this case, the detection locations of the points could be slightly different due to the lack of data for these specific points.
# Developments in Electric and Green Marine Ships
## 3 Technologies that Did or Will Shape the Future of Naval Travel and Trade
### Solar Ships of the Past  
The idea of using solar energy to power ships is not new. There are numerous examples of research studies, experiments, and prototypes that managed to do this. Between these prototypes, there are ships that use solar energy as an auxiliary means of power in order to cover the electricity needs of the ship, along with other renewable sources, and even as the only power source, as shown in Figures 2 and 3. However, solar energy is not considered to be able to fully power ships, because of the relatively small energy density that PVs provide. The latter is further analyzed in Section 5.  
The aforementioned need to turn to greener technologies in the naval sector led to the first steps of implementing solar energy as a power source in modern ships.  
An interesting example is the Auriga Leader, a car carrier ship for Toyota, back in 2009. The vessel is about 200 m long, weights around 60,000 tons, and carries up to 6200 cars, transporting them from Toyota Motor Corporation factories in Japan to the Port of Long Beach.  
On the Auriga Leader, 328 solar panels were installed on its top, providing a maximum power output of 40 KW [46]. This was the first time that a carrier ship used solar energy to cover part of its electricity needs, substituting the auxiliary diesel engines. In that occasion, the panel's installation did not only make the Auriga Leader greener by reducing the pollutants freed to the atmosphere, it also made it more economical and efficient by reducing the vessel's diesel consumption.
## 3 Simulations and Measurements
### Subjective Evaluation
In general, comparing the thresholds of the robustness evaluation scenario with that of main scenarios, it can be seen that, similar to the predictions of the intelligibility models, both the OE and proposed methods are very robust against changes in position and a detailed knowledge of the IR is not necessary. Figure 8: (**a**) Boxplots of speech reception thresholds at 50% speech intelligibility (SRT\({}_{50}\)) for 8 subjects, measured in the presence of SSN are illustrated. The unprocessed and the preprocessed signals for the main scenarios using the OE and proposed method are compared; (**b**) The mean-SRT\({}_{50}\) and the standard errors for the same data in (**a**) are plotted. Figure 9: (**a**) Boxplots of speech reception thresholds at SRT\({}_{50}\) for 8 subjects in the presence of pink noise (PN) are illustrated. The unprocessed and the preprocessed signals for the main scenarios using the OE and proposed method are compared; (**b**) The mean-SRT\({}_{50}\) and the standard errors for the same data are plotted.
## 7 Using IETF Standards to Realize the Internet of Things
### Security and Privacy in the Web of Things  
Applications running on embedded devices and LLNs often require confidentiality and integrity protection. These security mechanisms can be provided at the application, transport, network, and/or at the link layer. In all these cases, prevailing constraints will influence the choice of a particular protocol. Some of the more relevant constraints are small code size, low power operation, low complexity, and small bandwidth requirements.  
When securing embedded environments by using DTLS (as assumed within CoAP) at the transport layer, IPSec at the network layer, or reusing IEEE 802.15.4 security primitives within the 6 LoWPAN adaptation layer; the problem of key distribution remains mostly untackled. It is often assumed that each device has an appropriate asymmetric public and/or symmetric key installed. How these keys actually are distributed and installed in a safe way, is often left open and is not part of current IETF standards. To help solve this issue, work is executed within IETF's _Smart Object Lifecycle Architecture for Constrained Environments_ (SOLACE) [152].  
Apart from enabling secure communications between parties, privacy of WoT users is also an important concern. As embedded devices measure and control the physical environment that surrounds a WoT user, they can be (ab)used to gain insight into a user's habits and whereabouts. Therefore it is vital to enforce adequate access control to this sensitive information, in order to protect the user's privacy. As more and more internet-enabled things will gain an online presence, transparent and easy-to-use management of what information devices may expose to the outside world will be needed. For instance, you might want to give your AC vendor access to the temperature sensors in your house without allowing them to turn on and off your lighting. While you might want to allow a different vendor to only control your lighting. One approach as discussed in [153] is to group embedded devices into virtual networks and only expose certain resources within each virtual network, thus achieving access control at the network layer. Another option is to provide access control at the application layer, where access to resources on embedded devices is granted/revoked on a per-vendor basis and the application itself enforces the access control.
# Numerical Study of Cone Penetration Tests in Lunar Regolith for Strength Index
## 2 Numerical Model
### Constitutive Particle Contact Model of Lunar Regolith
\tag{9}\]  
where \(A_{\rm L}\) is the Hamaker coefficient calculated based on Lifshitz theory; \(R_{\rm c}\) is the contact surface radius; \(h\) is [PERSON]'s constant (approximately 6.63 \(\times\) 10\({}^{-34}\) J\(\cdot\)s); \(c\) is the speed of light (approximately 3 \(\times\) 10\({}^{8}\) m/s); \(D\) is the microscopic contact distance between lunar regolith particles; \(D_{\rm min}\) is the lower limit of the nonhysteretic van der Waals force range; \(D_{\rm 0}\) is the upper limit of the nonhysteretic van der Waals force range; \(D_{\rm 1}\) is the lower limit of the completely hysteretic van der Waals force range (Casimir force); and \(D_{\rm max}\) is the cutoff distance for Casimir force calculation. Figure 1: A contact mechanics model of lunar regolith particles. As the microscopic distance (\(D\)) between lunar regolith particles increases, the van der Waals forces between them begin to decay from a constant. The microscopic distance is considered to be a constant (\(D_{\text{min}}\)) when the particles are in very close contact, at which point the van der Waals force remains constant. The van der Waals force does not exhibit hysteresis and decreases cubically with \(D\) when the distance (\(D\)) is between \(D_{\text{min}}\) and \(D_{0}\). For distances between \(D_{0}\) and \(D_{1}\), the van der Waals force gradually transitions to the Casimir force, exhibiting hysteresis and linearly decreasing with \(D\). When \(D\) is between \(D_{1}\) and \(D_{2}\), the van der Waals force demonstrates complete hysteresis while transitioning to Casimir force, quadratically decreasing with \(D\). When \(D\) exceeds a certain value (\(D_{\text{max}}\)), the calculated Casimir force between particles becomes negligible compared with the other forces acting on the contact surface.
# Optimization of Technological Parameters of Straw Fiber-Based Plant Fiber Seeding Pot Raw Materials
## 1 Introduction  
Vegetable transplanting is an important link in the vegetable production process. Transplanting vegetables with seedling pots is an effective technical measure to increase production, quality, and efficiency, which can reduce the delayed period of seedlings in the field, increase the survival rate of seedlings, extend the growth period of seedlings, and increase the yield of vegetables. Raising vegetable seedlings in a nutrient pot can reduce the number of seeds used and cultivate strong seedlings. The standard seedling bowl made of traditional plastic material is not easy to degrade and will have a negative impact on the ecological environment. Under the global ecological environment with the implementation of the \"plastic limit order\" and the \"dual carbon\" goal, fully degradable materials can replace plastic materials and be applied to seedling pots, which is in line with the concept of green development.  
The common degradable seedling pots include paper pots, grass pots, nutrient pots, and biomass seedling pots. Using crop straw to make seedling pots can not only reduce-straw burning and effectively use straw [1], but also can degrade the straw-based materials into carbon dioxide and water after being treated by microorganisms in the soil, so that the biomass can circulate naturally and promote the benign development of the ecological environment. In related studies, some researchers studied the use of different raw materials to make seedling pots [2; 3; 4; 5; 6]; [PERSON] et al. [7] explored the preparation technology and parameter optimization of rice seedling plates; other researchers studied the degradability of the seedling pots made by different raw materials and processes [8; 9; 10]; still other researchers studied the different performances of different degradable seedling pots [11; 12; 13]; [PERSON] et al. [14] studied the degradable seedling bowl in the cultivation of Pinellia group application in seedling cultivation; and [PERSON] et al. [15] studied the recovery of residual substrate in the cultivation of Ganoderma lucidum mushroom and its application as a biodegradable horticultural seedling container. However, there are few reports on the use of plant fibers to prepare raw materials for thin-walled seedling pots.  
In order to eliminate the environmental pollution caused by plastic seedling pots, this research took the straw fiber-based plant fiber prepared by our research group as the main research object, and the technology of using plant fiber instead of plastic to be used as the raw material of the seedling pot; namely, wheat straw fiber and wood pulp fiber were laminated and mixed in a layered state, so as to explore the optimal combination of process parameters, and provide a theoretical basis and technical support for making seedling pots with straw fiber-based plant fiber.
## 3 Experiment and Results
### Boundary Constraints Based on Non Sky Region Light Intensity Values  
According to Equations (9) and (10), the key to solving the maximum and minimum transmittance lies in determining the maximum and minimum values of the target radiance. In most scenarios, fog does not uniformly occlude all pixels in an image. Certain target regions remain unobscured by haze. As shown in Figure 10c, black areas represent non-occluded target regions. Leveraging the similarity of target radiance within the same scene, we select the maximum and minimum window-averaged values of the target radiance from these black regions as its extremal values. As illustrated in Figure 11, red boxes mark regions for calculating the maximum target radiance, while blue boxes denote regions for the minimum target radiance.  
Figure 11: Target light selection Map in different scenarios.  
Figure 10: Segmentation maps under different scenarios: intensity threshold, DoP threshold, fused threshold, and sky region identification. (**a**): Intensity Threshold Segmentation Map; (**b**): DoP Threshold Segmentation Map; (**c**): Fused Threshold Segmentation Map; (**d**): Identified Sky Region Map.
## 4 Discussion  
The goal of this paper was to present the results of an experimental study that investigated the changes in the modal properties of composite rotor blades under icing conditions. Therefore, various icing conditions were simulated using a generic GFRP rotor disc within a climate chamber. A water spray system was utilised to generate different icing conditions on the rotor surface. As a reference, the effects of environmental conditions such as temperature changes were investigated. It has been evident that temperature changes cause significant changes in the modal properties of fibre reinforced plastics. The stiffening of the resin due to the cold temperatures increases the natural frequencies percentagewise in the multi-digit range. The numerical values are reproducible and stand out clearly from the noise. Static measurements show a good peak to noise ratio of three to four, which is due to the high sensitivity of the accelerometers. The main contribution to noise was caused by electrical interference generated by the operation of the electric motor dropping the ratio to one to two. However, the noise is in a clearly definable frequency range in the higher kilohertz range and can, therefore, be eliminated by filters such as low pass and moving average, providing clear frequency spectra. The results also show clearly distinguishable frequency shifts when the icing conditions are examined separately.  
To correlate changes in modal properties and ice accumulation, a laser scanning profiler was used to measure the ice distribution along the rotor circumference. The accuracy of the laser is accurate to a fraction of a millimetre and provides ice thickness profiles that enable results with good correlation. The icing conditions presented in this paper are also in good agreement with those from [4], in which prime ice was determined to be the usual type of icing on rotor blades.  
Figure 8: Frequency spectra illustrating the change in natural frequencies due to ice accumulation along the rotor radius, generated by opening all three nozzles (1, 1, 1).