esa-sceva/satcom-chunk-collection huggingface dataset:
## 2 Materials and Methods  
### Catalyst Preparation  
The structured \(\gamma\)-Al\({}_{2}\)O\({}_{3}\)/Al support was prepared by anodizing technology. Firstly, the commercial Al mesh (22 cm \(\times\) 28 cm) was soaked in 10 wt\(\%\) Al mesh cleaner for 7 min to remove oil stains on the surface of the Al mesh, then washed with deionized water and air-dried. Secondly, the aluminum mesh was anodized in 104 L of a 0.4 M oxalic acid solution under a current density of 25 A/m\({}^{2}\) and a constant temperature of 16 \({}^{\circ}\)C for 10 h in order to obtain the anodic aluminum oxide (AAO). The AAO was calcined at 350 \({}^{\circ}\)C in a muffle furnace to decompose residual oxalic acid on the surface. Thirdly, the AAO was hydrated in 80 \({}^{\circ}\)C deionized water for 1 h. Finally, the hydrated AAO was dried at room temperature followed by calcining at 500 \({}^{\circ}\)C in a muffle furnace for 4 h to form \(\gamma\)-Al\({}_{2}\)O\({}_{3}\)/Al support.  
The active components of Pd were loaded by impregnation. Firstly, the as-prepared \(\gamma\)-Al\({}_{2}\)O\({}_{3}\)/Al was impregnated in 400 mL of 1.3 g/L H\({}_{2}\)PdCl\({}_{4}\) solution for 24 h, and then dried and calcined at 550 \({}^{\circ}\)C for 4 h. Secondly, the calcined catalyst was reduced in 0.05 mol/L sodium borohydride solution for 4 h.
## 3 Methodology
### Inclusion Criteria and Sample Selection  
The research corpus focused on original double-blind peer-reviewed publications, following the criteria detailed below (Table 1): (a) the research period was confined to the last 6 years, given the novelty of the topic under study (2017-2023); (b) queries were performed on the title, abstract, and keywords, as they are considered to represent the essence of scholarly publications [31]; (c) the Scopus and WOS databases were used, as they are the main databases of quality scientific production [32; 33], and APA PsychInfo was used due to its being one of the most extensive databases in the field of psychology [34]; (d) publications in English were selected since it is the language of more than 75% of scientific production in the social sciences and 90% in the natural sciences [35; 36] and it was taken into account that the use of a single language for the analysis facilitates the identification of lexical relationships in the research corpus [31]; (e) only papers presenting empirical primary research were considered; (f) the subject of study should be related to the use of artificial intelligence to measure students' attention and concentration; and (g) the scope of the studies was education, considering all levels of education (primary, secondary, and higher).
## 5 Conclusions  
A novel AO-PSO-PF algorithm is proposed for location estimation, incorporating multiple steps to enhance positioning accuracy. First, PSO model is employed to obtain the preliminary positioning result of the WiFi part. The AO algorithm is applied to optimize the PF to integrate WiFi and PDR, thereby achieving precise indoor localization. Two experiments were conducted to compare the positioning performance of AO-PSO-PF with other algorithms including PDR, WiFi, PF, APF, and FPF. The results demonstrate that AO-PSO-PF outperforms the others, with average localization errors of 0.95 m and 1.42 m in the two experiments, respectively. Furthermore, the AO-PSO-PF algorithm exhibits robustness and adaptability across five users with four different motions, consistently maintaining low AE values and ensuring reliable performance in real-world applications.  
Nevertheless, there are some certain limitations that need to be approached in our future work. First, the resulting path is not sufficiently smooth. This issue may be attributed to multiple iterations of particle optimization, which increase the randomness of the particles and introduce some noisy particles. Future research could consider incorporating map information to constrain the particle movement area, thereby generating smoother positioning trajectories. Additionally, in more complex indoor scenarios with intricate pathways, the effectiveness of traditional algorithms may decline. In the future, DNN algorithms could be employed for further research in indoor positioning. Therefore, further validation is required to explore more solutions for practical indoor positioning challenges.  
Conceptualization, Z.L. and J.C.; methodology, Z.L. and S.S.; software, Z.L. and J.C.; validation, Z.L., S.S. and C.H.; formal analysis, Z.L.; investigation, Z.L.; resources, S.S. and J.C.; data curation, Z.L.; writing--original draft preparation, Z.L.; writing--review and editing, J.C. and C.H.; visualization, Z.L.; supervision, S.S.; project administration, S.S. All authors have read and agreed to the published version of the manuscript.  
This work was supported by Grants 2023 AY31004, the Research Project of Jiaxing Civil Technology Innovation Research, Central Guidance on Local Science and Technology Development Fund of ShanXi Province under Grant YDZJSX2023 ID005, and Innovative Education Special Project for Intelligent Navigation Applications in 2023 under Grant 2023 BD022.  
The data presented in this study are available on request from the corresponding author.  
The authors sincerely thank [PERSON] for providing assistance in revising the manuscript, especially in aspects such as writing, review, and editing.  
Author [PERSON] was employed by the company Zhejiang StreamRail Intelligent Control Technology Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
# MIMO Radio Frequency Identification: A Brief Survey
## 3 Anti-Collision Techniques
Perfect channel knowledge was assumed, and it was considered that all tag reply signals undergo block fading. The throughput of RFID standards such as EPCglobal is restricted by the tag collisions in multi-tag environments [53]. Since the number of tags are unknown at any point in time, they always exceed the frame length that must be equal to the number of tags to be read, hence complicating the performance of the anticollision algorithms. By improving the estimation process of tag quantity, the throughput of an RFID system can be greatly enhanced. Traditional receivers rely on single antenna systems and are usually difficult to be utilized for MIMO RFID systems as the low SNRs due to colliding tag signals degrade their performance significantly. [PERSON] et al. [45] came up with a multi-dimensional tag quantity estimation scheme for MIMO RFID systems that exploits spatial diversity at the multiple antennas of the receiver. The collided tag signals are stored in the form of high-dimensional vectors, thus making the estimation of tag quantity to be modeled as high-dimensional data clusters. It is observed that for a suitable SNR at various backscattering channels, the separation is enhanced by distance increments between clusters enabled by the modeling technique. Therefore, a density-based spatial clustering of applications with noise (DBSCAN) algorithm was integrated into the high-dimensional space to estimate tag quantities. Figure 6 explains the tag recovery algorithm used. The proposed technique outperforms various traditional approaches, and it is proved through simulations and experimentation. Identification performance in large RFID networks [54] is a key priority and multiple anti-collision techniques have been adopted in the past to enhance this metric. The authors of [46] propose a collision arbitration technique called group-based binary splitting algorithm (GBSA) to tackle the issue of tag collisions through arbitration strategies. The technique is a combination of estimation based on tag cardinality, a smart grouping strategy, and a modified binary splitting algorithm. An ML estimator [55] is employed for computing the cardinality. The tags are categorized into multiple groups according to the cardinality estimation and the optimal grouping design. For the case of multiple tag signals, filling the same time slot, a binary splitting technique is applied to them while the remaining tags are added to a queue and processed later for identification. The system is evaluated using mathematical models followed by simulations where it is observed that the proposed technique outperforms the existing anticollision techniques employed in UHF RFID readers. The use of GBSA technique enhances the system throughput significantly while reducing the complexity of the system. Figure 6: Flowchart of the tag recovery scheme. Reproduced from [45] with permission from IEEE.
# Lifting Activities Assessment Using Lumbosacral Compression and Shear Forces
## 4 Discussion  
In this study, we have analyzed the behavior of shear and compression forces at the L5-S1 joint (\(SF_{L5-S1}\) and \(CF_{L5-S1}\)) during the execution of controlled lifting tasks designed on the basis of the RNLE [4; 5] with an increasing lifting index (LI = 1, LI = 2, and LI = 3). Overall, due to how the LI is computed and the input variables that are considered, it is related to back compression, and for this reason, it is considered a good predictor of the risk of low-back incidents and overexertion injuries [5]. Higher LI values imply greater loads on the lumbosacral joint [4; 5; 27]. LIs higher than 1.0 but lower than 3 are assumed to represent lifting heavy loads activities that pose a risk for the lumbosacral joint, while LI values higher than 3.0 are referred to as highly stressful lifting tasks, implying an elevated risk of work-related low-back injury [28]. Furthermore, the scientific literature also highlights that higher LIs lead to higher kinematic and sEMG-based indexes, which, in turn, are positively correlated with compression and shear forces [14; 15]. In this study, these forces were calculated using both lower and upper body models, as presented by [PERSON] [24]. The findings highlight that the \(SF_{L5-S1}\) are related to risk levels: the maximum, mean, and range values significantly increase with LI (Figure 4, Table 1). These results are similar for both the used model, lower, and upper model (Figure 4, Table 1) and for all considered forces, the values of forces reported in N (\(SF_{L5-S1}\) in N, Figure 4a) are normalized with respect to the body weight (\(SF_{L5-S1 Norm}\) in N/kg, Figure 4b) and normalized with respect to the \(F_{L5-S1}\) during the standing phase (\(|SF_{L5-S10}-SF_{L5-S1 Norm}|\) in N, Figure 4c). Regarding the \(CF_{L5-S1}\), they are related to risk levels; however, the results are different with respect to the \(SF_{L5-S1}\) and depend on the parameters and force normalization. In particular, considering the values of forces reported in N (\(CF_{L5-S1}\), Figure 3a) and normalized with respect to the body weight (\(CF_{L5-S1,Norm}\) in N/kg, Figure 3b), the maximum
# Service Life Prediction and Life Cycle Costs of Light Weight Partitions
## 3 Methodology
### Occupancy Conditions  
In the research, six \"negative occupancy factors\" are identified as conditions within the living environment that have been found to negatively contribute to the deterioration and wear of partitions, thereby reducing their lifespan and performance. These factors can be more prevalent or impactful in specific residential settings, and include:  
1. Non-Ownership of the Dwelling: Renters or temporary occupants might not have the same incentive as owners to maintain or protect the property, potentially leading to quicker degradation.
2. Poor Maintenance (no maintenance activities for over three years): Lack of regular maintenance activities can deteriorate materials and fixtures.
3. High Residential Density (less than 30 m\({}^{2}\) per occupant): More people living in a smaller area can increase usage and physical impacts on partitions, and also the faster accumulation of dirt or damage.
4. Presence of Young Children: Young children (under 12 years-of-age) often engage in activities that can lead to more stains, impacts, or other forms of damage.
5. Domestic Animals: Pets can scratch, stain, or otherwise damage partitions, especially if they are not trained or their activities are not monitored.
6. High Object Density: Many objects within a living space can lead to more accidental impacts; mounting of fixtures; or modifications that can affect the partitions' integrity.  
Each observation was classified into one of four categories based on the number of negative factors. The number of Negative Occupancy Factors (\(\upmu\)) was used to define the service conditions as follows:  
\(\upmu=0\) Light service conditions  
\(2>\upmu\geq 1\) Moderate service conditions  
\(4>\upmu\geq 2\) Standard service conditions  
\(\upmu\geq 4\) Intensive service conditions  
In the study, statistical analysis of each service condition category was performed individually, and a comprehensive expression was also developed to reflect the combined influence of partition age and various negative occupancy factors on the partition wear patterns. This method helped to provide a detailed understanding of how different factors collectively impact the degradation of residential partitions.
###### Abstract  
As coal resource development progresses deeper underground, the increasing depth of mine shafts poses significant challenges to the safety and stability of traditional shaft construction methods, further compounding operational difficulties. In this context, cast-in-situ concrete shaft walls in a slurry environment have emerged as an effective solution. The strength of these shaft walls is a crucial parameter for assessing their safety. To explore this, experiments were conducted on slurry preparation and mortar casting (used here as a substitute for concrete) under three different conditions: slurry environment, pure water environment, and dry environment. The cast specimens underwent compressive, tensile, shear, and microscopic observation tests to analyze the strength development patterns of the mortar specimens in these varied casting environments. The study yielded several key findings: As the casting environment becomes more complex, the strength of the mortar specimens gradually decreases. Specifically, specimens cast in a slurry environment exhibit strengths approximately 15% to 20% lower than those cast in a dry environment, although both environments show similar trends in strength development over time. Across all casting environments, the initial strength loss of the specimens is significant, while the rate of strength loss decreases in the later stages; the strength loss is minimal in specimens cast in a pure water environment and reaches its maximum in those cast in a slurry environment. Additionally, in specimens cast in a slurry environment, air void diameter tends to polarize, and the distribution of air void is denser compared to the other two environments. In conclusion, cast-in-situ mortar in a slurry environment exhibits the lowest strength and the greatest strength loss compared to specimens cast in dry and pure water environments. Nonetheless, the strength development trends over time remain similar across all conditions, providing theoretical and technical support for the construction of shaft walls in slurry environments.  
s +
Footnote †: journal: applied sciences  
Article  
Experimental Study on the Strength Characteristics of Cast-In-Situ Mortar Specimens in a Slurry Environment
# Estimation of River Velocity and Discharge Based on Video Images and Deep Learning
## 3 Results and Discussion  
### Model Training  
The experimental hardware environment is an Intel (R) Core (TM) i7-6700K CPU @ 4.00 GHz and a NVIDIA GeForce RTX 2060 GPU with 6 GB of video memory; software environment is Windows 10 64 bit operating system, the program is run on Python 3.8, and the deep learning framework is PyTorch 1.9. The Adam optimizer is used to optimize the network backpropagation and the loss function is cross-entropy. The initial learning rate is 0.001, the number of training iterations is 200, and the batch size is 32.
## 3 Results and Discussion
### Correlation Analysis  
Backscatter values from all polarizations have been extracted at all sample plots and the distribution is depicted in Figure 8. The boxplot indicates that PALSAR-2 basically had stronger backscatter over the sample plots at both polarizations as compared to Sentinel-1A polarizations. Higher variation of PALSAR-2 HV polarization indicates the capability in discriminating AGB level. On the other hand, for Sentinel-1 data, VV polarization is more sensitive to the forest as compared to VH. These backscatter values were used in the correlation analysis.
# Design Procedure of a Frequency Reconfigurable Metasurface Antenna at mmWave Band
## 2 Related Works
### Contribution  
This paper proposes a unified simple design procedure used in antennas to calculate the geometrical parameters of SRRs, which are used in metasurface unit cells. The proposed unit cell is further used to design a PIN diode based elements reconfigurable metasurface antenna for the realization of dual band operation at mmWave frequencies. The main contributions of this chapter are summarized as follows:  
* Firstly, a demonstration of a step-by-step procedure on how to achieve SRR geometrical parameters at dual frequency of operation is provided;
* Secondly, the proposed unit cell was used to design a 16 element frequency RMS;
* Finally, the characteristics of the proposed frequency RMS were analyzed and compared with previous works.
# Gas-Liquid Mixability Study in a Jet-Stirred Tank for Mineral Flotation
## 3 Results and Discussion
### Influence of Aeration Volume on Flow Field  
With the slurry feeding rate maintained at 5.64 m\({}^{3}\)/h (inlet velocity of 5 m/s), the impact of the flow field was thoroughly examined by varying the aeration rates (air fraction, AF = 0.1, 0.15, 0.20, 0.25, and 0.30).
## 2 Literature Review  
In wireless communication, achieving a near-perfect transmission of energy from transmitter to receiver is challenging. This is particularly difficult in UOWC, due to inherent and environmental factors such as signal attenuation, misalignment, obstruction, reflection, refraction, and ambient noise. To overcome these challenges, strategies are needed to both transmit and capture photons effectively. While researchers often focus on strategies such as increasing the transmitting power of the signal and the area of photodetection, or addressing signal losses from attenuation and refraction by using complicated signaling strategies [4], state-of-the-art hardware-based strategies are underexplored.
# Potential Imaging Capability of Optical Coherence Tomography as Dental Optical Probe: A Mini-Review
## 3 Application of OCT for Subgingival Area Visualization
### Evaluation of Dental Profiles Marginal Adaptation  
The crown margin, known as the subgingival margin, is often located in the subgingival area [34]. Since it is essential to ensure that the crown is well-adapted to the prepared abutment tooth, the marginal adaptation of the crown needs to be carefully evaluated. An inadequate marginal fit can lead to microleakage and plaque deposition, which in turn can induce secondary caries, gingival inflammation, or even periodontal disease. A marginal fit of \(\leq\)120 \(\upmu\)m is acceptable in clinical practice [35], and this is within the resolution range of OCT. Hence, several studies have demonstrated the usefulness of OCT toward evaluating the marginal adaptation of interim/provisional [36,37] and ceramic crowns [38]. These in vitro studies used OCT images to assess the absolute marginal discrepancy [36,37] and  
Figure 1: Comparison and distribution of visible subgingival structures reported from the included literatures. The score in the \(y\)-axis indicates the number of literatures that reported the visibility of the subgingival structures.  
marginal gap [38]. However, and to the best of our knowledge, until now in vivo or ex vivo studies in either animal or human subjects have not been reported. Hence, the evidence of the applicability of OCT to evaluate marginal adaptation remains insufficient since it is not clear how periodontal tissues may influence the visibility of the subgingival margin area.
# LaRoAwan and Urban Waste Management--A Trial
## 1 Introduction  
Lisbon, as many other large cities, manages its waste by employing a number of systems associated to the smart city paradigm, such as monitoring waste levels in the containers and optimizing waste truck routes for each of the recycling waste types (common, organic, paper, plastic, and glass). The current system is based on legacy cellular technology, that as a legacy technology, poses a number of technical challenges and costs to the Lisbon City Council.  
Within the scope of the Lisbon Smart City project, underway at the Lisbon City Council (CML), it is intended to provide the city of Lisbon with an LPWAN (Low-Power Wide-Area Network) network, which will cover the entire city by making available a platform for low-speed and low-power communications with the set of sensors integrated in the municipality, following the principles of the Internet of Things (IoT). This network will allow the municipality to integrate a set of vertical applications, supported by a common communications network and platform, which will allow greater cost-effectiveness among different departments (and corresponding verticals) as opposed to the current data-as-a-service model, where each provider included a different network in their tender proposal.  
In order to support the smart city verticals, different LPWAN technologies that could be adopted by the municipality are currently available on the market. Among the possible alternatives [1], the following stand out:LoRaWAN (Low Range Wide Area Network)--the complementary network layer to the LoRa technology, which, by itself, only specifies the physical layer of the communications stack. This technology will be described in Section 2;
* Sigfox--an alternative network with the same aim, based on a closed business model, in which the network is always supported by an operator, also called Sigfox. This is the key difference to other technologies, there is only one operator;
* NB-IoT (Narrow Band IoT)--technology supported by public mobile communications networks, resulting from an evolution of the widely deployed LTE (Long-Term Evolution) technology. NB-IoT is the most recent IoT technology, its operating model is based on the conventional models of public mobile operators, based on a subscription.  
One of the smart city vertical applications in the municipality, with a project already underway, consists of sensing the city's waste containers. This project is supported by a set of sensors installed in the waste containers, which periodically report information on the filling level, this information is then integrated into a central management platform for this type of application. Communication with the installed set of sensors is currently supported through modems that use public mobile communications networks (based on GPRS--General Packet Radio Service) to transmit the container waste level measurement data.