esa-sceva/satcom-chunk-collection huggingface dataset:
# Efficient Tensor Sensing for RF Tomographic Imaging on GPUs
## 7 Conclusions  
In this work, we present an open-source library named cuTensorSensing for efficient RF tomographic imaging on GPUs. The experiment evaluations show that the proposed GPU tensor sensing works effectively and accurately. Compared with the counterpart on CPU, the GPU tensor sensing achieved a similar error rate, but much faster speed. For synthetic data, the GPU tensor sensing achieved an average of 44.79\(\times\) and up to 84.70\(\times\) speedups versus the CPU tensor sensing for bigger tensors. For IKEA Model 3D objects' data of a smaller tensor size, the GPU tensor sensing achieved a 15.37\(\times\) speedup over the CPU tensor sensing. The cuTensorSensing library is useful for efficient RF tomographic imaging.  
Figure 6: (**a**) The 3D visualization of the IKEA models and (**b**) the corresponding recovery results.  
Figure 7: RSE of the CPU tensor sensing and GPU tensor sensing.  
**Author Contributions:** Abstract, introduction, related works, conclusions, and the revising of the entire manuscript, T.Z.; algorithms, experiments, and results, D.X.  
**Funding:** This research is partially supported by the Natural Science Foundation of Shanghai under Grant No. 17 ZR1409800 and the Science and Technology Committee of Shanghai Municipality under Grant No. 16010500400.  
**Acknowledgments:** The authors would like to thank the anonymous reviewers for their fruitful feedback and comments, which have helped them improve the quality of this work.  
**Conflicts of Interest:** The authors declare no conflict of interest.
## 4 Conclusions  
We performed a theoretical functional density study of the electronic, magnetic and mechanical properties of Co\({}_{3-x}\)Cr\({}_{x}\)Al (x = 0, 1, 2, 3) Heusler compounds, with generalized gradient approximation (GGA) used for the exchange correlation potential. Two principal spin-related phenomena, the anomalous Hall effect and current spin polarization of the Co\({}_{3-x}\)Cr\({}_{x}\)Al Heusler compounds in the cubic \(L2_{1}\) structure, were discussed. Heusler compounds in two different atomic orders were considered. We found that the calculated magnetic moment of Co\({}_{3-x}\)Cr\({}_{x}\)Al decreased with an increasing Cr concentration for both ideal and inverse structures, except for Cr\({}_{3}\)Al. We also found that the spin polarization for all Co\({}_{3-x}\)Cr\({}_{x}\)Al was larger than 50%. Both the current spin polarization and Hall current spin polarization of Co\({}_{2}\)CrAl were high with the \(XA\) structure.  
Figure 4: (**a–c**) Band structures, anomalous Hall conductivity and number of valence electrons of Co\({}_{2}\)CrAl in the \(XA\) structure. (**d–f**) Band structures, anomalous Hall conductivity and number of valence electrons of regular Cr\({}_{3}\)Al. Dashed blue lines are the spin-up bands, and solid red lines are the spin-down bands. The Fermi energy is shifted to zero as in the references. The green dashed circles indicate predominantly spin-up or spin-down bands, which make large contributions to the anomalous Hall conductivity.  
**Author Contributions:** [PERSON] and [PERSON] contributed equally to this work; conceptualization, [PERSON] and [PERSON]; methodology, [PERSON]-[PERSON]; validation, [PERSON]-[PERSON]; formal analysis, [PERSON], [PERSON], [PERSON] and [PERSON]; investigation, [PERSON]; writing--original draft preparation, [PERSON], [PERSON] and [PERSON]; writing--review and editing, [PERSON], [PERSON] and [PERSON]; supervision, [PERSON] and [PERSON]. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the Ministry of Science and Technology (MOST), Taiwan, grant numbers 107-2112-M-039-002-MY2, 110-2218-E-A49-020-MBK and 111-2218-A49-026-MBK.  
**Acknowledgments:** The authors thank the Institute of Atomic and Molecular Sciences, Academia Sinica (IAMS) Taiwan and the National Center for High-Performance Computing, Taiwan, for providing the computer resources. The authors also thank [PERSON] from National Taiwan University for providing computer resources and programs.  
**Conflicts of Interest:** The authors declare no conflict of interest.
# Analysis of the Dynamic Behavior of Multi-Layered Soil Grounds
## 2 Materials and Methods
### Numerical Analysis
#### 2.3.2 Finite-Element Analysis  
ABAQUS is a formidable finite-element analysis software that enjoys widespread adoption in the simulation and analysis of soil behavior. In the realm of multi-layered soil modeling, ABAQUS boasts numerous advantages. Firstly, it provides sophisticated constitutive models to capture the behavior of soils under varying loading conditions. ABAQUS allows for the creation of realistic soil layering configurations, enabling engineers to simulate the response of multi-layered soil profiles to seismic, geotechnical loading. Additionally, ABAQUS offers robust meshing capabilities to discretize complex soil geometries efficiently, ensuring the accurate representation of soil layer interfaces and boundary conditions.  
In this study, multi-layered models were constructed within ABAQUS. Artificial seismic waves, Hachinohe seismic waves, and Ofunato seismic waves were applied at the base of each model to mirror conditions akin to those in the 1 g shaking-table test. The chosen constitutive model, the Mohr-Coulomb model, offers a straightforward yet robust representation of soil strength, encompassing critical factors such as cohesion and frictional resistance. The Mohr-Coulomb model accurately captures the shear behavior of soils under diverse loading scenarios. Table 4 outlines the parameters specific to the weathered soil A employed in the ABAQUS simulations.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter** & **Value** & **Parameter** & **Value** \\ \hline Density (kg/m\({}^{3}\)) & 2000 & \
\begin{tabular}{c} [PERSON]’s modulus \\ (MPa) \\ \end{tabular} & 20 \\ Poisson’s ratio & 0.3 &
\begin{tabular}{c} Cohesion yield stress \\ (kN) \\ \end{tabular} & 10 \\ Internal & 27 & Dilatancy angle (\({}^{\circ}\)) & 25 \\ Friction angle (\({}^{\circ}\)) & 0.9256 & Damping (beta) & 3.265 \(\times\) 10\({}^{-3}\) \\ \hline \hline \end{tabular}
\end{table}
Table 4: Soil input parameters used in ABAQUS (weathered soil A).  
The model was divided into a mesh with a size of 0.05 \(\times\) 0.05 m, which was the best mesh size obtained after multiple mesh-size tests. The infinite boundary section utilized CINPE4 elements, establishing a 2D framework bounded solely horizontally and vertically. Dynamic analysis was conducted with a fixed time increment of 0.001 s. Notably, the bottom boundary solely experienced horizontal acceleration and lacked vertical motion capacity. To mitigate boundary effects on the model analysis outcomes, both boundary sides were reconfigured as infinite boundaries, aligning their conditions as closely as feasible with those of the laminar shear box, as shown in Figure 6a. Figure 6b,c show the acceleration-time results and shear stress results.  
Figure 6: ABAQUS modeling and results: (**a**) infinite boundary; (**b**) acceleration–time result; (**c**) shear stress result.
## 1 PV to Supply 24% Electricity by 2050  
During the past 42 years (since 1976), PV module price dropped by 99.6% from $79.3/W to $0.3/W (both in 2018 USD), demonstrating a learning rate of 28.5% (Figure 1, [1]).  
Figure 1: Learning rate of crystalline silicon modules.  
Along with the cost reduction of other components in PV systems, the economics of PV electricity has significantly improved. Bloomberg NEF expects 24% of worldwide electricity consumption will be supplied by PV by 2050, when a total of about 7 TW PV will be installed (Figure 2, [2]).  
Despite the great potential of PV generation, continuous improvement is still needed before subsidies are eliminated. In industry, the 'grid parity' or'socket parity' is defined by comparing the levelized cost of electricity (LCOE, to be defined) of PV generation and local retail price. For behind-the-meter applications--for example, commercial PV projects--the realized value of PV generation depends on the flow of the electricity, unless net metering policy is applied. This is because exported energy (uploaded to the grid) is usually valued at much lower rates than the retail rates. Figure 3 shows the commercial socket parity achievement without generation-based subsidies by country in 2017 and expectation for 2025, assuming 75% on-site consumption ([3]). Although socket parity will spread to more countries by 2025, there are still regions where subsidies are required to boost local market development. More analysis on residential socket parity can be found in the literature ([3; 4]).  
Figure 3: Commercial PV socket parity in 2017 and 2025 with 75% on-site consumption. Note: Generation-based subsidies (in terms of $/kWh) are excluded in the calculation.  
Figure 2: Global electricity generation mix. Note: NEO is short for new energy outlook, which is an annual publication by Bloomberg NEF.  
In addition to further efforts to lower the unit electricity cost, PV also needs to have its intermittency addressed in order to realize deeper penetration compared with the 2% contribution in power system in 2018 (Figure 2). The coupling between PV and storage (PVS) is becoming an emerging market, thanks to cheaper lithium-ion batteries and the cost savings from synergy between PV and storage in the integrated system design. This point is mentioned here to provide a general and complete view of PV development. However, it is not the focus of this paper. More details about PVS can be found in the literature [5; 6].  
While there are still many challenges for PV to conquer before it can become a significant contributor to global electricity generation, we focus on one specific topic: how higher module efficiency can lower PV LCOE.
## 4 Conclusions  
In this section, the most relevant conclusions obtained from the research conducted on gypsum materials lightened with hemp in powder and fiber form are presented:  
* The partial replacement of gypsum with hemp in powder and fiber has been observed to decrease the surface hardness of the cured composites while reducing the compressive strength with respect to traditional gypsum material. Nevertheless, even with a decrease in strength of around 40% with a 30% substitution of gypsum with hemp in the most unfavorable case, the obtained strength still exceeded the minimum value set by regulations by more than 3 MPa.
* The G0.65-15%F compound exhibited the best results in flexural strength tests, achieving higher strength values than the reference material G0.65. Notably, in the study with prefabricated elements, all panels made with Kraft paper reinforcement exceeded the minimum value set by regulations at 0.18 kN.
* The composites with hemp incorporation showed a good performance against water action, reducing the water absorption through capillarity and the final height reached by the liquid inside the composite.
* All samples that used hemp as a partial substitution for gypsum obtained lower values of bulk density and thermal conductivity than the original composite G0.65, achieving a reduction in thermal conductivity close to 50% in some cases. Furthermore, SEM images demonstrated the effective integration of hemp material into the gypsum matrix, resulting in a homogeneous and cohesive distribution.  
Finally, it is worth noting that this research opens up new lines of work related to the design of sustainable building prefabricated. Future studies, for both powder and fiber composites, could complement this research by conducting acoustic tests and economic feasibility studies, and, most importantly, by comparing different surface treatments on hemp additions to assess their durability. In any case, the presented research has rigorously collected the results obtained in a designed experimental campaign, achieving the goal of demonstrating to professionals and specialists in the building sector the potential applications of hemp material as a partial substitution in lightweight gypsum composites.  
Conceptualization, D.F. and A.Z.-B.; methodology, D.F. and M.A.; software, D.F. and M.A.; validation, D.F, A.Z.-B. and P.S.; formal analysis, D.F.; investigation, M.A. and A.Z.-B.; resources, D.F. and P.S.; data curation, D.F.; writing--original draft preparation, D.F.; writing--review and editing, A.Z.-B., A.C.-G. and P.S.; visualization, A.C.-G.; supervision, P.S.; project administration, D.F. and P.S. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
Data are contained within the article.  
The authors would like to express their gratitude to [PERSON] from Bialystok University of Technology (Bialystok, Poland) for providing the hemp material used in this research.  
The authors declare no conflicts of interest.
# Similarity Estimation for Large-Scale Human Action Video Data on Spark
## 1 Introduction
At first, we deploy a Apache Spark based cluster environment. Our proposed method is divided into a feature extraction phase and similarity measure of extracted features respectively. We store all human action videos into the Hadoop Distributed File System (HDFS) and videos stored in HDFS are loaded into a Spark cluster represented by resilient distributed datasets (RDDs) [16]. During the process of RDD partition and transformation, we adopt flatMap (e.g., which is similar to map function, but each input element can be mapped to 0 or more output elements) included in Spark Core to process human action similarity computation in parallel in every worker node including the master node. Moreover, we proposed a novel feature descriptor called Edge based Local Descriptor pattern that can extract shape features and texture features as well, which is inspired from Local Binary Pattern [17], and Local Ternary Pattern [18] that only extract texture information. We obtain the final feature vector using our proposed ELP. Next, feature vectors are saved into HDFS. After that, we compute the similarity between feature vectors using cosine similarity. Finally, in order to validate the performance of our proposed descriptor, we performed mean average precision on the UCF (University of Central Florida) Sports action dataset [19]. The experimental result shows that proposed ELP has better performance, compared with other feature descriptors. Moreover, the scalability of proposed approach is evaluated. The rest of the article is organized as follows: in Section 2, related work is shown. In Section 3, we describe our proposed framework including preprocessing, feature extraction and similarity measure components. In Section 4, we implement the proposed method by conducting experiments and analyze experiment results. In Section 5, we discuss performance of the proposed approach and application scenarios using the proposed method. In Section 6, we get conclusions and future work.
## 1 Introduction
Hence, we define the resilient modulus as the ratio of the repeated deviatoric stress to recoverable strain [31; 32; 33] (4):  
\[M_{r}=\frac{\sigma_{d}}{\varepsilon_{r}}, \tag{4}\]  
where \(\sigma_{d}\) is the applied repeated deviatoric stress and \(\varepsilon_{r}\) is the axial recoverable strain. In a small strain range, the resilient modulus is equivalent to Young's modulus. Therefore, data obtained from a torsional shear test can be easily transformed from the shear modulus to [PERSON]'s modulus by applying the following relationship (5):  
\[M_{r}=E=2G(1+v) \tag{5}\]  
where \(v\) is Poisson's ratio; hence, the knowledge about the shear modulus value can be easily translated to the resilient modulus value, and no additional cyclic loading tests are required. To complement the existing literature, we performed tests on unsaturated silty soil in a small strain range to find the relationship between the unsaturated soil state parameters and the shear modulus characteristics. The tests were conducted to extend the knowledge about the soil behavior during dynamic loading. Moreover, the tested soil was compacted to simulate the subgrade conditions. To present the silty soil behavior fully, we performed laboratory tests to identify the following soil properties:  
* Determination of the impact of compaction on the consolidation properties of the tested soil to verify if compaction creates a soil preconsolidation state and to ensure the same consolidation conditions during the tests. * Characterization of the small strain behavior of the soil with the use of the resonant column test to obtain the initial shear modulus and shear modulus characteristics, as well as the damping ratio characteristics. * Normalization of small strain data with respect to existing \(G_{0}\) and \(D_{0}\) empirical models. * Undrained triaxial tests to measure the soil suction of silty soil specimens and the initial shear modulus value with the use of the bender element test. Finally, we evaluated gathered data with existing empirical models, and we proposed the empirical model for unsaturated silty soil for initial shear modulus calculation.
# Collaborative Robotics: Enhance Maintenance Procedures on Primary Flight Control Servo-Actuators
## 3 Critical Aspects Related to the Automatic Adjustments Procedures
### Mechanical-Related Challenges
#### 3.1.2 Adjustments Acceptability Threshold  
According to the unit maintenance manual, each adjustment must bring a specific output (i.e., a current, voltage, or ram position) within predefined boundaries. As an example, Figure 6a reports the end of the adjustment of the ram position, obtained by regulating the orientation of the hexagonal screw pictured in Figure 6b.  
As it is possible to see from the graph, at t \(\approx\) 50 s, the adjustment is completed, so, after changing the tool, the two safety screws can be fastened. However, since these two elements are mechanically connected with the hexagonal screw, this operation affects the value of the ram position read by the measurement system. The same effect, even though smaller in magnitude, is also reported in Figure 5b, where the fastening of the three safety screws tend to lower the EHSV current. In addition, at t \(\approx\) 27 s, it can also be noticed how the removal of the screwdriver at the end of the adjustment affects the servo-valve current, probably related to a settlement of the slotted screw to a condition of equilibrium.  
To guarantee that, at the end of the entire procedure (adjustment plus tightening of the safety screws), the monitored output is within the desired ranges, two solutions have been adopted:  
1. The safety screws must be unfastened by a precise quantity, or until reaching a specific torque, obtained by empirical experience, so that the plate, which connects the item to be adjusted and the safety screws, is not too much loosened. If not, while screwing back the safety screws, it could move and compromise the entire procedure;
2. The acceptability thresholds defined to the robot for completing the adjustment must be more stringent than those reported on the maintenance manual. In so doing, even after fastening back the safety screws, the output would be within the boundaries.
## 3 Result and Discussion
### Water Absorption  
The effect of soaking time on water absorption of the prepared samples has been investigated. The results showed that water absorption of the specimens increases from 1 to 24 h of being soaked (Figure 2). The reported results are the average of three samples.  
Figure 2: The trend of water absorption for different geopolymers after 1, 3, 6, and 24 h, respectively.  
Meanwhile, the relation between porosity, water absorption, and compressive strength showed that increment in porosity increases water absorption, while the residual compressive strength of the specimens is inversely proportional to both water absorption and porosity (Table 4).  
Taking into account the necessity of having high water absorption and compressive strength in the prepared geopolymers for evaporative cooling application, the DOE software selected sample 16, which reported a \(\sim\)38% of water absorption and \(\sim\)5 MPa compressive strength.  
Despite the fact that porous material such as porous ceramic and geopolymer was previously fabricated as evaporative cooling materials by [33; 34; 35], this research developed a greener geopolymer by utilizing a significant amount of industrial and agricultural waste as secondary raw materials, resulting in excellent waste management and sustainable production (Table 5).  
The development of geopolymer materials is in accordance with the requirements of sustainable development; it not only require lower processing temperatures, but can also utilize significant amounts of industrial and agricultural waste materials as a secondary raw material, and convert them to a new product. The creation of a new material from different industrial and agricultural waste and by-products might result in reduced energy consumption, reduction of waste production, reduction of global CO\({}_{2}\) emissions, as well as the reduction of exploitation of natural resources. Geopolymers can be customized to a wide variety of properties and characteristics, depending on its constituents or processing methods. Some of these properties include compressive strength, shrinkage, setting, acid resistance, fire resistance, and thermal conductivity. However, these properties are not inherent in all of the geopolymeric formulations. In this case, inorganic polymers should be regarded as the solution to problems associated with the material selection, but as a solution that can be tailored by a correct mix and processing design that will optimize properties and/or deduct the costs for a given application.
## 3 Results
### Stability Analysis of Multi-Temporal Calibration Results
#### 3.1.3 Ohs-F CMOS3 Calibration Results and Analysis  
Figure 11 shows the comprehensive gains of the CMOS3 sensor in 2020 and 2021. In 2020, the RB of the comprehensive gains of the CMOS3 sensor at the wavelength range of 550 nm to 880 nm was basically approximately 10%, while the RB of the comprehensive gains for the bands with central wavelengths outside this wavelength range was higher, with the maximum value exceeding 20%. In 2021, except for the bands of 441 nm, 910 nm, 926 nm, and 940 nm, the RB of the comprehensive gains of the other bands on different dates was about 6%, indicating that the radiometric performance stability of the CMOS3 sensor in 2021 was significantly better than that in 2020.  
It is noted that the radiometric stability of three CMOS sensors on-board the OHS-F satellite in 2020 was lower than that in 2021, which was mainly caused by the great change in radiometric stability in the early stage of the satellite launch. At the same time, the above analysis results also show that the comprehensive gains calculated in different calibration sites and different integral stages had high consistency. Therefore, the use of satellite data in different sites and different integration stages is expected to obtain high-frequency and stable radiometric calibration results, which can more effectively describe the changes in the radiometric performance of satellite sensors and enable the high-frequency calibration of micro-nano satellite constellations.  
Figure 10: Calibration results for OHS-F CMOS2. (**a**) Description of comprehensive gains in 2020; (**b**) description of averaged value and SD of comprehensive gains in 2020; (**c**) description of comprehensive gains in 2021; (**d**) description of averaged value and SD of comprehensive gains in 2021.