esa-sceva/satcom-chunk-collection huggingface dataset:
## 4 Discussion  
The multichannel orthogonal correlation detection method proposed in this paper aims to tackle the problem of multi-station multi-frequency signal detection. Through simulation and actual measurement, it was shown that the proposed method can satisfy the detection of the Alpha navigation signal. The proposed method can be easily implemented on a field-programmable gate array (FPGA) digital chip, which changes the problem of signal detection and timing synchronization in an analog circuit of an Alpha navigation receiver. This method not only satisfies the requirement of alpha navigation signal detection, but also satisfies the strict requirement of timing in navigation and timing applications after it is implemented on an FPGA chip. Although this method is practical, the following two points can be further explored:  
1. To pursue the practicability of the method, a classical bandpass filter was adopted in this study to suppress the noise. In future work, we can study the performance of the detection method using modern filtering techniques such as empirical mode decomposition and wavelet filtering. We believe that the application of these techniques will not only improve the anti-noise performance of the proposed method, but also make the phase measurement of the alpha navigation signal more accurate.
2. Although the detection method is proposed for the transmission characteristics of Alpha navigation signals, the three frequency signals of each station extracted by the notch filtering in the method can be used for the detection of signal parameters, and they meet the phase difference measurement of digital signals in the Alpha positioning receiver. Therefore, the detection method will be applied in research on signal parameter measurement and the positioning method of an Alpha receiver in the future.  
Figure 12: Notch filter and signal detection results of received signal. (**a**) Three frequency signals signal obtained via notch filter. (**b**) \(f_{1}\) signal detection results. (**c**) \(f_{2}\) signal detection results. (**d**) \(f_{3}\) signal detection results.
# Numerical Simulation of Non-Isothermal Mixing Flow Characteristics with ELES Method
###### Abstract  
Thermal fatigue caused by turbulent thermal mixing in tee pipes is always one of the failure factors of industrial pipes. At present, computational fluid dynamics (CFD) is still the main research method to study the thermal fatigue mechanism. Due to the limitations of the large eddy simulation (LES) model and the classical Reynolds Averaged Navier-Stokes (RANS) model in simulating thermal mixing, an advanced Embedded LES (ELES) model was developed. By comparing the model with data in the open literature, the validity of the ELES model to iso-thermal mixing was evaluated and proven. After that, the flow characteristics of the backflow upstream with different momentum ratios (\(M_{R}\)) were studied using the ELES method, as well as the temperature characteristics near the wall where the backflow appears. It was found that the characteristics of the backflow and the temperature distribution upstream in the tee were different with different \(M_{R}\) values and some regions under specified \(M_{R}\) values are found to be more prone to thermal fatigue at the intersection of the tee upstream. Moreover, the frequency analysis at specified points near the wall under three different \(M_{R}\) values was estimated to evaluate thermal fatigue and the results showed that long-period fluctuations of lower frequencies than 6 Hz upstream were observed. This work helps form a comprehensive understanding of the backflow in thermal mixing and the relationship between fatigue and backflow in the tee.  
tee pipe; large eddy simulation; non-isothermal mixing; ELES; thermal fatigue +
Footnote †: journal: Applied Sciences  
Acticle Numerical Simulation of Non-Isothermal Mixing Flow Characteristics with ELES Method
## 1 Introduction
Satellite SIF provides a feasible method for large-scale diagnosis of sugarcane drought at a large spatial scale. As SIF is sensitive to environmental stresses, such as drought and extreme temperature, it has been used to monitor the response of crops to environmental stresses [27; 48; 49; 50; 51]. For example, previous studies suggested that satellite SIF is more sensitive than VIs in terms of capturing the responses of wheat, maize, and rice to drought or extreme temperature stresses [1; 25; 27]. However, our understanding of the different response patterns of sugarcane SIF and VIs to drought stress is limited, and the possible response mechanism of sugarcane SIF to drought is also unclear thus far. As sugarcane-planting areas are relatively fragmented, the spatial resolution of SIF observed by satellite measures is coarse, which makes it difficult to detect the responses of sugarcane to drought stress using the original satellite SIF. Recently, the spatial resolution of satellite SIF was enhanced by fusing the original satellite SIF with additional products from different remote sensing platforms based on spatial downscaling methods. Downscaled satellite SIF products, such as SIF* [52],RSIF [53], CSIF [54], Downscaled-GOME2-SIF [55], DSIF [56], GOSIF [57], SIFnet [58], and HSIF [59], have been produced. These downscaled satellite SIF products are of finer spatial resolutions (0.05 degrees), but with different time periods. The GOSIF dataset covers a long time period, has high spatiotemporal continuity, and has been successfully used to monitor the response of crops to drought [60], vegetation dynamics [61], and photosynthetic phenology [62]. In this work, we explore the potential of downscaled satellite SIF for assessing the impacts of drought on sugarcane. China is the third-largest sugarcane-planting region in the world [8]. Sugarcane is mainly planted in subtropical areas of southwest China, especially in the Guangxi Province. Chongzuo City is the most important sugarcane-planting region in the Guangxi Province and is also the largest sugarcane-planting region and sugar production base in China. Annual sugar production from sugarcane in Chongzuo City is approximately 2 million tons, and accounts for approximately 1/5 of the total production of China [8; 63; 64]. The area of the sugarcane-planting region has been relatively stable for many years in this city [8; 63; 65]. However, more than 80% of sugarcane is planted in dry and hilly land where irrigation is also commonly not accessible, and sugarcane-planting regions are much more vulnerable to drought stress. Therefore, we explore the potential of utilizing satellite observations of SIF and EVI to assess the impacts of drought stress on sugarcane, with a special focus on an extremely severe drought event in Chongzuo City, in this work. The main objectives of this work are to explore the different response patterns of sugarcane SIF and a traditional vegetation index to drought, analyze the sensitivity of SIF to drought stress in the critical growth periods of sugarcane, and analyze whether SIF can serve as an effective indicator for estimating sugarcane yields or GPP.
# Computational Load Analysis of a Galileo OSNMA-Read Receiver for ARM-Based Embedded Platforms +
## 3 Development Work  
The NGene receivers represent a good set of choices for the implementation and testing of the OSNMA functionality on different platforms, including standard PCs [17; 19], ARM-based embedded platforms [20], and Android smartphones [27]. Apart from the adaptations needed by the different platforms, all the receivers belonging to the NGene portfolio share the same core processing and features:  
* The real-time capability of processing the GPS, Galileo and EGNOS signals broadcasted on the L1/E1 band;
* The implementation of the whole GNSS signal elaboration chain, from the acquisition to the position velocity and time (PVT) computation;
* The Software-Defined-Radio (SDR) approach, which offers the highest level of maintainability, flexibility and portability of a fully software implementation;
* The support for several L1/E1 radio frequency (RF) USB front ends (FEs) [28; 29; 30; 31], allowing the user to also specify a custom FE.  
In particular, most of the functionalities are coded in ANSI-C, allowing for a high level of portability among different operating systems (OSs) and platforms, and only the modules that have to process high data rates, such as the samples coming from the FE at tens of megahertz (e.g., 1-16 MHz), are coded in assembly language, exploiting processor-specific optimizations.  
Both the receivers considered in this paper, i.e., NGene [17] and eNGene [20], require a Linux operating system, but while the former can be executed by standard PCs, the latter is tailored to ARM-based embedded platforms, as better described in the next subsection. Figure 2 shows an illustrative picture of all NGene family's receivers developed along more than one decade.  
Figure 2: NGene: the set of receivers belonging to the family and their derivation.
## 4 Illustrative Examples  
### RLC Circuit  
Consider a simple electrical circuit (see Figure 1) which consists of (connected in series) an inductor, a resistor, a capacitor (R-resitor, L-inductor, C-capacitor - RLC), and a voltage source. The resistor and capacitor are considered to be non-linear electrical elements, which means that they have non-linear characteristics. In the circuit presented in Figure 1, there also exists a noise signal, such that  
\[z_{\mathrm{u}}^{\mathrm{max}}=\max_{i,t\geq 0}z_{\mathrm{u}}(i,t)\geq 0\,. \tag{31}\]  
The dynamic behaviour of the circuit can be described by the equation:  
\[L\frac{\mathrm{d}i(t)}{\mathrm{d}t}+R(i)i(t)+\frac{q(t)}{C(q)}=u(t)+z_{ \mathrm{u}}(i,t)\,. \tag{32}\]  
Denote \(x(t)=q(t)\), \(\dot{x}(t)=\dot{q}(t)=i(t)\), \(F(\dot{x})=L^{-1}R(\dot{x})\), \(G(x)=L^{-1}C(x)^{-1}\), \(H=L^{-1}\), and \(z(\dot{x},t)=L^{-1}z_{\mathrm{u}}(\dot{x},t)\). Then, the equation (32) can be presented in the form of (1). Table 1 contains a list of the circuit and controller parameters. The values for these parameters have been chosen mostly heuristically, trying to cover the largest possible range of parameter variability. In order to achieve particular system performance objectives, a proper performance index shall be defined, and values of the parameters can then be obtained as a result of solving the optimization problem. This type of optimization problem can be quite easily solved by using numerical optmization methods. It is also easy to check that Assumptions 1-3 are valid. The simulation results are shown in Figures 2-8. The results confirm the property of finite-time convergence of the closed-loop system, as well as robustness to disturbances.  
Figure 1: Non-linear RLC (R-resitor, L-inductor, C-capacitor) circuit with a noise signal.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{2}{c}{**RLC Circuit**} & \multicolumn{3}{c}{**Controller**} \\ \hline
**Parameter** & **Value** & **Unit** & **Parameter** & **Value** & **Unit** \\ \hline \(C(q)\) & \(10^{-2}\left(1+0.2\mathrm{e}^{-0.1q^{2}}\right)\) & F & \(x_{\mathrm{d}}(t)\) & 0 & C \\ \(i(0)\) & \(-0.1\) & A &  
Figure 4: Effects of changes in the \(\gamma\) parameter on the system trajectory \(x\).  
Figure 3: Effects of changes in the \(\sigma\) parameter on the system trajectory \(\dot{x}\).  
Figure 5: Effects of changes in the \(\sigma\) parameter on the system trajectory \(\dot{x}\).  
Figure 6: Effects of changes in the \(\gamma\) parameter on the system trajectory \(x\).  
Figure 8: Control signal \(u\) in a sliding mode control manner.  
Figure 7: Effects of changes in the \(\eta\) parameter on the system trajectory \(\dot{x}\).
# Performance of Solar Control Films on Building Glazing: A Literature Review
## 3 Solar Control Films  
A solar control film (SCF), as previously referred to, is a thin laminate film that is applied to glazing systems to modify their solar optical and thermal properties in order to increase their performance. Currently, there is a broad variety of SCFs for new and retrofitted glass, with application on both internal and external glass surfaces, that are suitable for cold and hot climates.  
This section summarizes the existing types of SCFs and their impact on the main solar optical and thermal properties of the glazing systems they are applied to. The information present in this section is relevant to later discussion about which types of SCFs are less studied and to better comprehend the impact these films have on the properties of the glazing system when installed in single and double clear glazing (representative of the most common glazing solutions).
## 4 Energy Consumption Analysis
### Energy Production According to the Active Elements  
The energy production is greater in elementary schools than in large offices located in the same area. This is because, even in buildings with the same volume, the determination of the solar installation capacity is dominated by the size of the roof area (Figure 6).  
Figure 5: Energy consumption at each orientation: (**a**) large office; (**b**) primary school.  
Depending on the building location, the energy production in Busan is greater than that in Seoul because the amount of insolation in Busan is higher than in Seoul. Therefore, in the design of zero-energy buildings, differences in production by region should be considered.  
As for the energy production according to the orientation of the building, as shown in Table 7, the energy production is largest in the west and least in the northeast. This result is due to the installation of a building-integrated photovoltaic module, and assuming that the rooftop solar power is designed to face south, the power generation amount is the highest when the module installed on the side of a square building is a west-facing building that receives maximum sunlight hours. As a result, west-facing buildings produce more electricity in the afternoon when the sun sets than south-facing buildings, which can reduce dependence on external electricity during peak hours at 3 p.m.
## 4 Conclusions  
A new cathodic protection element to control the corrosive potential in chloride molten salts as a thermal energy storage material for CSP plants was analyzed in the paper. Key conclusions include the following:  
1. By adding Al metal into chloride molten salts (cathodic protection), the reduction potential of the alloy can be controlled. The most thermodynamically stable form of chromium in the alloys tested is hence the metallic chromium, meaning that selective oxidation of chromium in the Cr-containing alloys did not occur.
2. This behavior can be explained by the formation of Al\({}_{2}\)O\({}_{3}\) in the alloy surface which can generate a passivation layer and hence a reduction of the electrolysis current and lower corrosion rates.  
This behavior can be a successful starting point to continue with corrosion mitigation strategies focused on cathodic protection using aluminum metal to achieve a CSP plant lifetime of 30 years or longer.  
Conceptualization, A.G.F. and L.F.C.; methodology, A.G.F. and L.F.C.; lab testing, A.G.F.; software, A.G.F.; formal analysis, A.G.F., and L.F.C.; investigation, A.G.F. and L.F.C.; writing--original draft preparation, A.G.F.; writing--review and editing, L.F.C.; supervision, L.F.C.; project administration, A.G.F. and L.F.C.; funding acquisition, A.G.F. and L.F.C. All authors have read and agreed to the published version of the manuscript. This project has received funding from the European Union's Horizon 2020 research and innovation program under the [PERSON] grant No 712949 (TECNIOspring PLUS) and from the Agency for Business Competitiveness of the Government of Catalonia. This work was partially funded by the Ministerio de Ciencia, Innovacion y Universidades de Espana (RTI2018-093849-B-C31 - MCIU/AEI/FEDER, UE). This work was partially funded by the Ministerio de Ciencia, Innovacion y Universidades - AgencHa Estatal de Investigacion (AEI, RED2018-102431-T). This work is partially supported by ICREA under the ICREA Academia program. The authors would like to thank the Catalan Government for the quality accreditation given to their research group (GREiA 2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Alloys** & **Ecorr (mV)** & **Icorr (mA)** & **\$c (mV)** & **\$a (mV)** & **A (cm2)** & **CR (mm/y)** \\ \hline OCT & \(-\)87.32 & 2098.62 & 280.8 & 465.6 & 4.20 & 4.37 \\ HR224 & \(-\)31.16 & 210.62 & 239.7 & 241.3 & 6.75 & 0.27 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Electrochemical parameters and corrosion rates obtained and linear polarization resistance (LPR) test for OCT and HR224 alloys.
## 3 Technology Developments for Production of Carotenoids
### Genome Engineering for Strain Development
Multiplex automated genome engineering (MAGE) simultaneously targets many locations on the chromosome for modification in a single cell or across a population of cells by directing ssDNA to the lagging strand of the replication fork during DNA replication [116]. The modifications can cover gene inactivation, expression regulations, and so on. Aforementioned twenty genes related to lycopene production have been targeted to tune their expression using a complex pool of synthetic DNAs, and lycopene production is increased more than five-fold. A complementary method called trackable multiplex recombineering (TRMR) has been developed to simultaneously map genome modifications that affect a trait of interest, which combines parallel DNA synthesis, recombineering and molecular barcode technology to enable rapid modification of all _E. coli_ genes in an _a priori_ knowledge-independent way [117]. Metabolic engineering for the production of valuable compounds often heavily relies on plasmid-based expression of the synthesis pathway in a heterologous host. Although plasmids are easily manipulated and allow strong expression of targeted enzymes, the plasmid-based systems suffer from genetic instability such as plasmid loss, an additional antibiotic cost, and a potential risk of antibiotic marker spreading to other organisms [118]. Accordingly, chromosomal integration of the production pathway promises the host to achieve stable overproduction of the desirable chemicals including carotenoids. By \(\lambda\)-Red homologous recombination, plasmid-free engineered _E. coli_ strain has been developed to produce lycopene and astaxanthin [119]. The expression cassettes can be integrated into different loci to increase the number of gene copies. P1 transduction usually plays a role in transfering the different alleles between host strains. Recently, an intelligent strategy called chemically inducible chromosomal evolution (ClChE) has been developed to reduce the daunting repeated one-at-a-time tasks in the chromosomal integration of target genes [88]. ClChE allows the host to acquire a high gene copy (up to 40 copies) expression of integrated pathways with increasing concentration of selective chemicals, and the increased copy number is stabilized by the removal of the _recA_ gene. With this approach, lycopene production has been increased by 60% from single copy integrated strain. The ClChE strategy has been further modified to eliminate antibiotic marker for environmental safety and health issue after the evolution of the recombinant host strain [120].
# Dynamic Downsampling Algorithm for 3D Point Cloud Map Based on Voxel Filtering
## 1 Introduction  
With the rapid development of hardware devices for acquiring 3D point cloud data, such as lidar [1] and depth cameras [2], the number of 3D point cloud data that can be acquired is getting larger and larger. Three-dimensional point cloud data are widely used in autonomous driving [3; 4; 5], robots [6], augmented virtual reality [7], and smart cities [8; 9]. More and more attention is being paid to research on 3D point cloud technology. In the field of smart home, equipment such as sweeping robots [10] and robot housekeeping [11] need to construct 3D point cloud maps of indoor scenes. However, a 3D point cloud map in an indoor environment alone has hundreds of millions of points. Processing such a huge point cloud map, therefore, requires a lot of computing resources. The downsampling of 3D point cloud data plays a key role in subsequent operations, such as segmentation [12], classification [13], and target recognition of 3D point cloud maps [14; 15; 16; 17].  
Point cloud downsampling methods can be categorized into deep learning-based [18; 19; 20], grid-based [21; 22], clustering-based [23], and voxel-based downsampling methods [24]. Although, in recent years, researchers have made significant progress in point cloud downsampling, the challenges of detail loss and parameter tuning remain unresolved.  
To address these issues in 3D point cloud downsampling, we investigate the downsampling algorithms for 3D point clouds and propose a dynamic downsampling algorithm for 3D point cloud maps based on voxel filtering. This algorithm aims to retain the edge information of point clouds. We introduce two modules: the dynamic downsamplingmodule and the point cloud edge extraction module. The former dynamically segments 3D point cloud maps to perform adaptive voxel downsampling, while the latter preserves the edge information in 3D point cloud maps. We conduct comparative experiments with other downsampling algorithms, demonstrating the superior simplification effect of our proposed downsampling method.  
The structure of the paper is organized as follows: In Section 2, we provide an overview of the background and significance of downsampling 3D point clouds. Section 3 introduces the principle of voxel downsampling and highlights the challenges associated with voxel downsampling. Section 4 presents the dynamic downsampling algorithm for 3D point cloud maps based on voxel filtering. In Section 5, we conduct comparative experiments between our downsampling algorithm and other existing methods, demonstrating the superior simplification effect of our approach. Finally, Section 7 summarizes the innovative aspects and contribution of this research paper and identifies its limitation.
# On the Fault Detection and Diagnosis of Railway Switch and Crossing Systems: An Overview
### Sensors and Controllers  
Different kinds of sensors are used in railway S&C systems depending on the type of actuation and on the locking mechanism. The sensors are mostly used for controlling the movement of the switch or running the motors and detecting the position of the switch rails. HW machines, which use voltage and current sensors, are widely used in the UK rail network [24; 43]. [PERSON] et al. [44] studied the failure analysis and CM of Style 63 (i.e., M63) point machines, which were in operation in the UK. The current and force sensor data from Style 63 machines were used in this study. The force was measured and the variation of the force profile during the actuation was analyzed to detect any possible faults present in the system. But, in all these traditional point machines, the sensor data are not used for closed-loop control of the switch actuation. The sensor data are used either to detect the position or for future fault diagnosis or CM application.  
HPSS switch systems--shown in Figure 7--measure the linear position of switch rails at the toe position and also record the current data from the electrical motors. These sensor signals are fed back to the controller, which is designed as a cascaded controller, for controlled motion of the switch rails.  
Figure 6: Schematic of a lift-hop-drop actuation: REPOINT light track switch.  
Figure 7: Schematic of HPSS actuator with LVDTs attached.