esa-sceva/satcom-chunk-collection huggingface dataset:
# UWB-Based Real-Time Indoor Positioning Systems: A Comprehensive Review
## 5 Real-Time UWB Indoor Positioning Systems (RTIPSs)
### Real-Time Implementation Ranging and Topologies
#### 5.2.1 Two-Way Ranging-Based Indoor Positioning Systems
(2020) investigated the multiple error corrections of clock drift between the reference anchor and the tag for the DecaWave DW1000 transceiver (Qorvo Inc., Greensboro, NC, USA) and analyzed the most common TWR protocols in real-time implementations. The test results showed that alternative double-sided two-way ranging (AltDS-TWR) has the best results, and that it can correct the signal power and hardware delays for every UWB unit individually. The used UWB unit was the Qorvo (DecaWave) EVK1000, which consists of the DW1000 IC with the ST32F105 (STMicroelectronics, Geneva, Switzerland) microcontroller and has a built-in LCD, various interfaces (JTAG, SPI, USB), and a wideband planar omnidirectional antenna. [PERSON] et al. (2020) proposed two general active-passive two-way ranging (TWR) methods for UWB-based IPSs: The first (AP1-TWR) uses the UWB packet exchange and listens to the other anchors' transmissions, with knowledge about the anchors' locations. The second (AP2-TWR) only listens to the other anchors' transmissions. The experimental tests were conducted using the Eliko UWB RTLS (OU Eliko Technology, Tallinin, Estonia), which is based on the DecaWave DW1000 module. Five fixed anchors and one tag were used, and the distances between the anchors and the anchor coordinates were measured using the DISTO S910 (Leica Geosystems AG, Heerbrugg, Switzerland) laser distance meter. Both methods were tested with the SS-TWR, SDS-TWR, and AltDS-TWR active ranging methods. The results indicated that the AP2-TWR method consistently outperforms the AP1-TWR method by about 10 to 20%. [PERSON] et al. (2020) proposed a real-time approach for optimal anchor node selection in TWR. Instead of ranging with all nearby anchors, including those with poor channel characteristics, the new method allowed for the selection of the best-performing anchors based on the best link quality. This new approach enhances the accuracy by up to 15 cm, which represents a 50% improvement compared with traditional TWR. The practical tests were implemented using the Wi-Pos UWB open-source platform, which includes the Qorvo DW1000 transceiver with wireless backbone. Other TWR-based IPSs have been proposed in ([PERSON] et al., 2020; [PERSON] et al., 2020; [PERSON] et al., 2020).
# Evapotranspiration Prediction Method Based on K-Means Clustering and QPSO-MKELM Model
## 2 Materials and Methods
### Correlation Analysis and Variance  
Evapotranspiration (ET\({}_{0}\)) has a complex nonlinear relationship with various meteorological factors, and among these, the FAO-56 model, while highly accurate, requires many meteorological inputs. However, these inputs are often incomplete, which limits the model's applicability. In contrast, machine learning can build models and make predictions even when data are incomplete. It is important to note that different meteorological data contain varying amounts of information about evapotranspiration. Thus, we can perform correlation and variance analyses to preliminarily select features, providing a valuable reference for constructing the final model.  
Correlation analysis is used to study the relationships between variables or between variables and outputs. This study employs the maximal information coefficient (MIC) [39], a correlation measure from information theory. MIC can capture both linear relationships between features and evapotranspiration, as well as complex nonlinear relationships among them.  
Variance is a statistical measure that describes the degree of data dispersion and quantifies how much data points deviate from the mean. The variance of a feature reflects its numerical variation range. However, variances cannot be directly used to measure information content due to differences in units and scales among features. By computing the variance of normalized features, the variation of different features can be compared on the same scale, enabling the quantification of the information contained in each feature; the larger the normalized variance, the more information the feature carries.
# Optimisation of Synchronous Grouting Mix Ratio for Shield Tunnels
## 2 Materials and Methods  
### Raw Materials  
The cement selected was a PO 42.5 grade ordinary Portland cement (Yangchun Hailuo Cement Co., Ltd., Canton, China), because Portland cement possesses good frost resistance, wear resistance [23], and corrosion resistance [24], and this grade of silicate concrete can guarantee a certain level of strength. The fly ash (Guangzhou Yueyu Concrete Building Materials Co., Ltd., Canton, China) used was grade II with a fineness, sieve residue, water demand ratio, loss on ignition, water content, sulphur trioxide content, and stability of 45 \(\upmu\)m, 23%, 102%, 3.47%, 0.6%, 1.6%, and 4.3 mm, respectively. Material fluidity, early strength, and elastic modulus should be ensured [25], and type II fly ash should be selected to improve the performance of grouting slurry at a lower cost [26]. The bentonite used was composed of sodium, which can enhance the impermeability and crack resistance of the slurry [27]. The chemical compositions of the three materials are listed in Table 1. A polycarboxylate high-efficiency water-reducing agent was used, with a water-reducing rate of 40-50%. A redispersible latex powder (herein latex powder) was used. River sand is commonly used in engineering projects, and river sand with a fineness modulus of 2.1 was selected as the aggregate.
## 6 Conclusions  
In this paper, we presented the technical characteristics of the scanning imaging mode for aerial cameras and addressed the issue of image motion resulting from this working mechanism, highlighting the necessity for image-motion compensation in the application of aerial scanning imaging cameras. On this basis, research on the image-motion compensation technology of an aerial camera based on the multi-dimensional motion of the secondary mirror was carried out. The secondary mirror served as the compensatory element for image motion, enabling comprehensive compensation for forward/scanning image motion through its deflection motion. The paper presented an analysis of the effects of the multi-dimensional motion of the secondary mirror on the first-order parameters and the third-order aberration fields, and also provided a design case. To validate the image-motion compensation capability of the secondary mirror's image-motion compensation mechanism, laboratory and flight imaging experiments were carried out. The laboratory experimental results demonstrated that the dynamic resolution of the aerial camera achieved 74 lp/mm through the use of secondary mirror deflection motion for image-motion compensation, and the accuracy of this image-motion compensation method was better than 0.5 pixels. Furthermore, the flight experimental results demonstrated that the aerial camera, based on the multi-dimensional motion of the secondary mirror for image-motion compensation, worked stably, and was capable of acquiring high-quality images. Due to limited conditions, only laboratory and flight imaging experiments have been conducted. Subsequently, the imaging experiment and the verification experiment of the image-motion compensation technology under vacuum conditions will be carried out to facilitate applications in near  
Figure 10: Urban flight experiment imaging results: (**a**) R-spectral band; (**b**) G-spectral band; (**c**) B-spectral band; (**d**) NIR spectral band; and (**e**) RGB image fusion.  
space and space-based environments. In conclusion, the experimental results demonstrate that the integrated design approach for imaging and image-motion compensation is feasible and can be widely applied to the development of ground-based, air-based, near-space, and space-based optical imaging systems.  
Conceptualization, H.Z.; methodology, H.Z.; software, H.Z. and R.Q.; writing--original draft preparation, H.Z.; writing--review and editing, W.C. and H.G.; supervision, W.C. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The data presented in this study are available from the first author or the corresponding author upon reasonable request.  
The authors declare no conflicts of interest.
# Design Study of Steel Fibre Reinforced Concrete Shaft Lining for Swelling Ground in Toronto, Canada
## 3 Key Design Issues  
The bedrock below the city of Toronto is known for being comprised of Georgian Bay shale and contains inter-beds of significantly stronger limestone, siltstone, and sandstone. Additionally, it is reported that the bedrock exhibits long-term TDD behaviour when the shale experiences stress relief and is exposed to freshwater [39]. Therefore, a potential heave of the base and swell of the sidewalls of the shaft structure in the bedrock were anticipated. Geological studies for the projected area were conducted to establish the geotechnical baselines for the project, by describing the prevalent soil, bedrock, and groundwater conditions [40]. In consideration of the fully developed nature of the area and the presence of 20 and 30 m-deep ravines along the route, it was proposed to construct the tunnel entirely within the underlying shale bedrock, which lies at a depth of approximately 40-50 m to reduce the risk of impacts on the ground surface. Therefore, the tunnel was designed at a depth of 60-80 m to obtain sufficient unweathered fresh rock cover, as shown in Figure 2.  
Various geotechnical laboratory tests were performed to evaluate the ground properties using retrieved rock cores from each borehole: (1) soil overburden testing to evaluate the water content, grain size, and alterberg limit, (2) bedrock strength testing to estimate unconfined compressive strength (UCS), (3) 100-days free swell tests of bedrock to investigate the swelling potential, (4) geophysics investigation to establish the elevation and variation in underlying bedrock. Standpipe piezometers with 31 mm diameter polyvinyl chloride (PVC) pipe were typically installed at the bottom of each borehole to estimate the groundwater level [45]. Based on the above laboratory tests, as a baseline condition, it was assumed that construction of a permanent shaft liner can only commence once the convergence monitoring results indicate that stable shaft convergence conditions have been achieved and a minimum period of 3 months have passed between shaft excavation and lining construction [40].  
Figure 1: Detailed site and borehole location.
## 1 Introduction
### Remote Sensing Context
Red-edge information has the potential to considerably improve monitoring of forest health from satellites and warrants further investigation in other ecosystems. [PERSON] et al. (2018); [PERSON] et al. (2018) used multispectral data (the 4 band CASI sensor) and hyperspectral data from a spectrometer to predict moisture deficits in oaks infected with an emerging oak disease. They found several band and band ratios in the SWIR (short-wave infrared) spectra (e.g., 975 nm, 1200 nm, and 1750 nm) that were useful in separating the water status of specific leaves, but the accuracy of distinguishing differences in leaf water status using only 4 band multispectral imagery was difficult. Satellite-based remote sensing information has and is clearly helping to advance many agricultural and ecological research programs. Unmanned aerial vehicles (UAVs) present a new and potentially very different opportunity to monitor protected and semi managed lands with on-demand high spatial and temporal resolution (Stein  
using the common California shrub coyote brush, _Baccharis pilularis_, at the Blue Oak Ranch Reserve (BORR) outside of San Jose, in central California. In each manipulation, plants were completely cut from their root systems and propped up vertically in their original orientation. These treatment cuttings were staggered and occurred once every other day for one week. Therefore, the UAV images we obtained were of the same plant species at various stages of desiccation. Control and watered plots were also established for reference. We hypothesized that we would observe reduced NIR reflectance values and increased red and red-edge reflectance values (indicating reduced photosynthetic capacity), along with decreased relative water content and water potential values, due to immediate and severe water limitation. To test these hypotheses, we had three main objectives. First, we explored the empirical relationship between two common multispectral remote sensing indices (NDVI and NDRE) and water content and water potential across experimental plots with a gradient of water limitation. Second, we sought to understand the applicability of imagery from off-the-shelf cameras and UAVs to detect slight variations in plant responses to water limitation across the gradient. As part of this objective, we tested the effect of ground sample distance (GSD, i.e., flying height) and time of day on detectability of plant stress. Finally, we explored how relationships between indices and the detectability of water limitation changed when the imagery was scaled to coarser resolutions provided by PlanetScope imagery.
## 3 Modeling of the VLC System and Its Components in the Indoor Environment
### The Mathematical Model of the Behavior of a Convex Mirror  
For a convex mirror, the direction of reflected light depends on the curvature of the surface. Reflection can be modeled using the geometry of a spherical mirror, where the radius of curvature \(R\) defines the dispersion of light. The reflection equation for a convex mirror can be expressed as follows:  
\[\theta_{i}\
eq\theta_{r}, \tag{3}\]  
where the reflection angle \(\theta_{r}\) varies depending on the position on the mirror surface.  
On the other hand, for a convex mirror, the dispersion of reflected light can be modeled by considering that incident rays parallel to the principal axis of a convex mirror diverge as if they were coming from a virtual focal point. The focal length \(f\) is related to the radius of curvature \(R\) by the following equation [19; 20]:  
\[f=\frac{R}{2}. \tag{4}\]  
The intensity of reflected light decreases as the light disperses. The intensity distribution pattern can be modeled using radiation distribution functions that depend on the geometry of the convex mirror.  
To address the problem of modeling signal propagation in an indoor VLC system with LoS blocking and the use of an IRS, which consists of an array of flat and convex mirrors, it is essential to analyze how the reflective components of the signal interact with these elements. The following are the signal propagation models for both cases.
## 3 Results  
### Pressure Drop Characterization Tests  
The single-channel model was used to reproduce the Pressure Drop Characterization Tests, and the BE methodology was applied to calibrate it. Since the purpose of the characterization tests was the evaluation of the pressure drops across each one of the 10 channels constituting the FWMU, the selected response for the methodology was the pressure difference (Ap) between inlet and outlet. Instead, four parameters were selected for each channel:  
* The loss coefficient in the junction connecting the vertical nozzle to the FWMU channel (\(K_{v}\));
* The loss coefficient in the 180\({}^{\circ}\) bend (\(K_{b}\));
* The loss coefficient in the junction connecting the FWMU channel to the horizontal nozzle (\(K_{h}\));
* The surface roughness (\(\epsilon\)).  
Figure 4: Wall–wall heat transfer model.  
The choice to consider each channel independent from the others is pushed from the different behavior shown by each channel in the pressure drop characterization tests. However, albeit independent, the initial parameter values were adopted identical for all the channels, with an exception for Channel 1, for which the default results were too distant from the experimental ones (this discrepancy is linked with the faulty welding described in Section 2.3).  
As an outcome of the best-estimate methodology, mean calibrated parameters were obtained (Table 1). As it can be depicted from Table 1, the calibrated surface roughness is identical for each channel, and it is also identical to the initial assumed value. This behavior highlights their small influence on these tests. Instead, the spreading of the \(K_{v}\), \(K_{b}\), and \(K_{h}\) values indicate their preeminent influence in shaping the pressure losses through the channels. The different values shown for each channel are a direct reflection of the different pressure losses experimentally shown through the tests.  
The results coming from an input deck adopting these values are compared against the experimental data and the initial estimation in Figure 5 (only Channels 3, 4, 7, and 8 in the flow directions relevant for the LOFA transients). As it can be seen, the Best-Estimate runs reproduce the behavior observed in the experimental tests well enough, even though deviations at high air mass flow rates (\(>\)32/34 g/s) are shown. Most likely, the reason is to be found in the set of adopted parameter values for each channel. In principle, a high number of sets can be able to match the pressure drops at each given mass flow rate, but finding a set capable to reproduce all of them together is a more complex task. Therefore, the differences at high mass flow rate suggest only that the chosen set--through the best-estimate methodology--is good enough to reproduce the total pressure drop when its behavior is quasi-linear, but that is not sufficient when the pressure drops stray from linearity.
# Some Plant Food Products Present on the Polish Market Are a Source of Vitamin B12
## 3 Results and Discussion
Many fermented plant products were also analyzed in the past, including a Japanese type of fermented black tea (Batabata-cha), containing a significant amount of vitamin B12, up to over 4500 ug\(\cdot\)kg\({}^{-1}\) of dry tea leaves and 20 ug\(\cdot\)L\({}^{-1}\) of tea drink [14]. Unfortunately, such products are not popular in Central Europe, especially in Poland. Therefore, in our study, we examined products that are constantly in the diet of Poles. In this study, the concentration of vitamin B12 in pickled cucumbers, sauerkraut, juices and other fermented products, as well as sea-buckthorn jam available on the Polish market were analyzed. All samples were obtained from ready-made products available from shops. Most samples were found to contain minor traces or no vitamin B12. [PERSON] et al. [27] reported more than half the amount of vitamin B12, in comparison with our results, in fenugreek leaf juice (120 ug\(\cdot\)L\({}^{-1}\)). In the cited work, LAB also participated in the fermentation process. [PERSON] et al. [21], who analyzed sauerkraut, reported significantly different results. In their study, they used specific bacterial strains for fermentation and checked how much vitamin B12 they could produce. The fermentation process was carried out with LAB and a combination of LAB and propionicobacteria. In their study, the content of vitamin B12 reached 72 and 20 ug\(\cdot\)kg\({}^{-1}\) with and without the addition of propionicobacteria, respectively. The authors pointed out that such large amounts of vitamin B12 resulted from the fact that production was controlled compared to commercially made sauerkraut, which contained significantly smaller amounts of this vitamin (1.3 ug\(\cdot\)kg\({}^{-1}\)). In this study, we found only traces of vitamin B12 in sauerkraut. Several factors, including differences in the microbiological composition of the products, storage conditions, age of the sauerkraut and the method of production, could have influenced this result. This may be a plausible explanation for why vitamin B12 could not be detected in our studies. A high content of vitamin B12 (50 ug\(\cdot\)kg\({}^{-1}\)) was determined in pickled parsley juice. This would mean that half a glass of such juice would cover the daily requirement of an adult for vitamin B12. In addition to fermented products, sea-buckthorn jam was also analyzed. A significant amount of vitamin B12 was determined (220 ug\(\cdot\)kg\({}^{-1}\)). This would mean that an adult would only need to eat 18 g a day of this food product, which is about 1.5 tablespoons, to cover the daily requirement for vitamin B12. Similar results were obtained by [PERSON] et al. [12] by the analysis of sea-buckthorn fruits for vitamin B12. The authors determined that 100 g of dry matter contained as much as 37.01 ug of vitamin B12. This means that sea buckthorn may be the richest source of vitamin B12 among all plants.
# Hybrid Fault Diagnosis of Bearings: Adaptive Fuzzy Orthonormal-ARX Robust Feedback Observer
## 1 Introduction
The effectiveness of the proposed method for fault detection and identification is compared with that of SFO and FO and evaluated using two different datasets: (a) the Case Western Reverse University (CWRU) vibration bearing dataset to test single-type faults [5; 21], and (b) the Smart HSE Lab AE bearing data set to test multi-type faults [5; 10; 21]. Figure 1 illustrates a block diagram of the fuzzy orthonormal-ARX adaptive fuzzy logic-structure feedback observer. The main contributions of this research are:  
1. Develop an accurate and robust system modeling using a fuzzy orthonormal-ARX bearing modeling for vibration and AE signals. 2. Develop an accurate, robust, and reliable technique for signal estimation based on the fuzzy orthonormal-ARX adaptive fuzzy logic-structure feedback observer. 3. Improve the performance of fault detection and classification based on generating the differentiable residual signals, extract the energy features from residual signals, and applied to machine learning (SVM) technique in parallel with the fuzzy orthonormal-ARX adaptive fuzzy logic-structure feedback observer. This paper is organized as follows. The second section outlines the bearing modeling for the vibration and AE signals based on the fuzzy orthonormal-ARX technique. The third section has two main sub-parts: firstly, the fuzzy orthonormal-ARX adaptive fuzzy logic-structure feedback observer is used to signal estimation and (b) the machine-learning technique based on the SVM is developed for fault detection and identification. In the fourth section, the datasets are introduced and the proposed method for fault diagnosis of REBs is analyzed. Conclusions are provided in the last section.
# Driverless Bus Path Tracking Based on Fuzzy Pure Pursuit Control with a Front Axle Reference
###### Abstract  
Currently, since the model of a driverless bus is not clear, it is difficult for most traditional path tracking methods to achieve a trade-off between accuracy and stability, especially in the case of driverless buses. In terms of solving this problem, a path-tracking controller based on a Fuzzy Pure Pursuit Control with a Front Axle Reference (FPPC-FAR) is proposed in this paper. Firstly, the reference point of Pure Pursuit is moved from the rear axle to the front axle. It relieves the influence caused by the ignorance of the bus's lateral dynamic characteristics and improves the stability of Pure Pursuit. Secondly, a fuzzy parameter self-tuning method is applied to improve the accuracy and robustness of the path-tracking controller. Thirdly, a feedback-feedforward control algorithm is devised for velocity control, which enhances the velocity tracking efficiency. The proportional-integral (PI) controller is indicated for feedback control, and the gravity acceleration component in the car's forward direction is used in feedforward control. Finally, a series of experiments is conducted to illustrate the excellent performances of proposed methods.  
driverless bus; path tracking; pure pursuit; fuzzy logic control; feedback-feedforward control +
Footnote †: journal: Applied Sciences