esa-sceva/satcom-chunk-collection huggingface dataset:
# Millimeter-Wave High-Gain Dual-Polarized Flat Luneburg Lens Antenna with Reflection Cancellation
###### Abstract
In this case, the foci are usually no longer kept at the transformed end surfaces of the cylinder but shifted to a certain distance from the lens surface. An evolutionary design is performed by performing an alternating coordinate transformation to maintain a zero focal length as that of a conventional LL in [22], where a 1D lens is demonstrated. However, the radiation performance, in terms of both gain and beam scanning loss, is deteriorated drastically due to the reflection caused by the used high permittivity materials or structures. The typical achieved gain of this type of FLL is around 13-16 dBi, and the corresponding aperture  
Figure 1: Various Luneburg lenses: (**a**) conventional LL, (**b**) layered LL with concentric spherical shells, (**c**) horizontally placed cylindrical flat LL, (**d**) vertically placed cylindrical flat LL. efficiency is around 20-46% [19; 20; 21; 22]. Hence, the low gain or low efficiency performance of such type of FLLs limits their applications. To alleviate the reflection caused by the used high permittivity materials or structures, a structural-based optimal design of FLL is proposed in this work. The performance of either a conventional LL or a vertically placed FLL is firstly compared in a quantitative way. Then, a flat LL antenna (FLLA) is designed using the reflection cancellation method to reduce the reflected wave and increase the gain and efficiency, simultaneously. The designed FLLA is exemplified at the _Ka_-band, exhibiting wideband, dual-polarized, and beam-scanning properties. Specifically, the achieved aperture efficiency of the proposed antenna is superior to previous works [20; 21; 22], and high-gain performance is achieved with a good front-to-back ratio (FTBR). The rest of this paper is organized as follows: Section 2 provides a performance comparison between a conventional LL and an FLL to reveal the performance degeneration due to the flat design. Section 3 discusses the flat design method and the introduced reflection cancellation scheme for the FLL. Section 4 shows the implementation and measurement of the designed FLLA. A conclusion is made in Section 5, and a future work is discussed as well.
## 2 Materials and Methods  
### Site Description and Crop Management  
The study was carried out in two sites of the Colombian Andean region, in the western Savanna province of the department of Cundinamarca. The evaluation of the potato rainfed production system (hereinafter Rainfed) was carried out in a 6 hectares (ha) commercial plot (4.87033\({}^{\circ}\) N, \(-\)74.1294\({}^{\circ}\) W; \(-\)2572 m above sea level). The potato irrigated production system (hereinafter Irrigated) was evaluated in a 3.11 ha commercial lot, under a fixed-sprinkler irrigation system (4.888668\({}^{\circ}\) N, \(-\)74.18668\({}^{\circ}\) W; \(-\)2609 m above sea level). Both potato (_Solanum tuberosum_ L.) production systems used the Diacol Capiro variety. The sowing date for Rainfed was 1 August 2020, and the sowing date for Irrigated was 22 January 2021. The plant density was 33,333 pl ha\({}^{-1}\) for both production systems. The two sites are located over a fluvio-lacustrine plain with a flat landscape, an average annual temperature of 12-14 \({}^{\circ}\)C, and annual precipitation between the 800-1000 mm bimodally distributed. The June-August and December-February periods have the lowest rainfall, due to the double passage of the Intertropical Convergence Zone (ITCZ). The soil of the two production systems is deep and well-drained, with the presence of volcanic ash corresponding to the Andisol order [19]. Potato cultivation can be established at any time of the year due to Colombia's climate offer due to its geographical location. Common practices include sowing vegetative or asexual seeds, foliar and soil fertilization, weed control, hilling (earthing up), insecticide, and fungicide treatment, haulm cutting, chemical dehaulming, and harvesting.
## 5 Results
### Comparison of Confidence Estimation Strategies  
Based on the GLR framework, we replace the confidence evaluation module with alternative methods. In addition to the P(True) approach, the MC Dropout method performs five stochastic forward passes during inference to compute the average confidence. The  
Figure 7: Effect of varying the number of candidate entities on GLR performance.  
ensemble method further calculates the arithmetic mean of the confidence scores obtained from both P(True) and MC Dropout for each candidate. Evaluation metrics include MRR, Hits@1, and the average inference time per query (in seconds).  
As shown in Table 5, the P(True) method achieves competitive accuracy (MRR = 0.804, Hits@1 = 0.715) with an average inference time of 1.17 s. MC Dropout yields slightly higher accuracy (MRR = 0.816, Hits@1 = 0.724) but incurs a significantly longer inference time of 5.08 s per query. The ensemble method attains the highest accuracy (MRR = 0.831, Hits@1 = 0.736), accompanied by the highest latency of 6.35 s. Overall, while MC Dropout and the ensemble approach offer modest improvements in prediction accuracy, they introduce considerable computational overhead. In contrast, P(True) provides a favorable trade-off between accuracy and efficiency, making it a highly practical solution for real-world deployment.
## 2 Materials and Methods
### System and Elements
#### 2.1.1 NIRS Measurement  
We used the LABNIRS system (Shimadzu Corporation, Kyoto, Japan) to measure variation in [HbO] and [HbR] from local cortical areas. The LABNIRS system applies three wavelengths of near-infrared light (780 nm, 805 nm, and 830 nm) to measure hemoglobin concentrations. The system offers both measured light intensities and hemoglobin concentrations converted simultaneously in real time. We used the [HbO] and [HbR] directly offered by the system.  
We used four pairs of NIRS emitting and detecting optodes, resulting in nine measurement channels. The distance between an emitter and a detector was 30 mm, enabling a measurement depth -20 mm from the scalp. The optodes were positioned on the scalp surface around the motor cortex (C3) according to the international 10-20 system (Figure 2). In particular, emitting optode 4 was on the C3. We combined a Shimadzu FLASH holder kit (Flexible Adjustable Surface Holder) with a swimming cap for more stable fixation of the NIRS optodes and for prevention of the potential effect of ambient light. We set the sampling interval to 120 ms, resulting in the sampling rate of 8.33 Hz. This sampling interval was sufficient, because the hemodynamic responses induced by the motor task occurred at around 0.1 Hz [10].
# Propospheric Attenuation in GeoSurf Satellite Constellations
## 3 Global GeoSurf Probability Distributions of Rain Attenuation
Figure 4: The difference \(A_{GEO}-A_{Z}\), calculated at fixed annual probabilities 1% (**a**), 0.1% (**b**), and 0.01% (**c**), between the rain attenuation exceeded in the GEO path, \(A_{GEO}\), and the rain attenuation exceeded in the GeoSurf path, \(A_{Z}\), i.e., at the zenith in Robledo; 39.6 GHz, circular polarization. Figure 5: The difference \(A_{GEO}-A_{Z}\), calculated at fixed annual probabilities 1% (**a**), 0.1% (**b**), and 0.01% (**c**), between the rain attenuation exceeded in the GEO path, \(A_{GEO}\), and the rain attenuation exceeded in the GeoSurf path, \(A_{Z}\), i.e., at the zenith in Holmdel; 39.6 GHz, circular polarization. Figure 6: The difference \(A_{GEO}-A_{Z}\), calculated at fixed annual probabilities 1% (**a**), 0.1% (**b**), and 0.01% (**c**), between the rain attenuation exceeded in the GEO path, \(A_{GEO}\), and the rain attenuation exceeded in the GeoSurf path, \(A_{Z}\), i.e., at the zenith in Pasadena; 39.6 GHz, circular polarization. In these figures, we have not further shown the ITU\(-\)R predictions because this model gives unexplainable large differences, \(A_{GEO}-A_{Z}\), at low latitudes, as it does for the Spino d'Adda longitude. These values are very different from the values predicted by the other models, especially those based on some physical insight, such as Excell and Global SST. Now, because the purpose of the present paper is not to investigate the reliability of the ITU\(-\)R model at low latitudes, we have abandoned its use at these latitudes in order not to bias the reader's perception of the various comparisons. In conclusion, the comparison between GEO and GeoSurf paths shows that when the latitude is in the range of \(\sim\)20\({}^{\circ}\)N to \(\sim\) 20\({}^{\circ}\)S (GEO elevation angle larger than about 67\({}^{\circ}\)), the GEO path is less attenuated, particularly at a probability of 0.01%, which corresponds, of course, to high rain rates and very concentrated rain cells, differently sampled by the zenith path and the slant paths, as predicted by Global SST. At the zenith, the path is always filled with rain, while in the GEO slant paths, changing the elevation angle can make significant difference, because of the small linear extension of high intensity rain cells. Now, the path can be directed along the periphery of the cell, on average, as envisaged by the Global SST, which mimics what is directly observable with the full SST. This physical effect is also present, although just slightly pronounced, in the Excell model predictions. In the next section, we calculate, for a specific case, the probability distribution of rain attenuation predicted for LEO satellites.
## 6 Conclusions  
This study relied on a foundation pit project at the Zhongyilu Station of the Wuhan Metro Line 12. Numerical simulations were conducted to analyze the influence of different construction stages on the deformation of the foundation pit. The original scheme was optimized through the use of segmental pouring of the main structure and the installation of internal supports. The main conclusions are as follows:  
1. Both the horizontal displacement of the diaphragm wall and the ground surface settlement gradually increased with the excavation of the foundation pit, while the differential settlement between the diaphragm wall and the lattice columns showed a differential settlement that initially decreased then increased.
2. Comparative analysis with the cut-and-cover method indicated that the top-down method is more effective in terms of controlling the deformation of the foundation pit and reducing the impact of construction activities on the surrounding environment.
3. A construction scheme was proposed, involving multiple segmented pouring of the main structure and erection of internal supports. This scheme can effectively reduce the deformation of the foundation pit. However, in this project, with the increase in the number of segments, the growth of the deformation control effect is not obvious. Therefore, in this project, considering deformation and economy comprehensively, Plan 2 is selected as the best.
4. In future research, real-time monitoring data will be incorporated. By installing sensors in actual engineering projects, real-time data on soil deformation, stress, and other key parameters will be collected. This will be used to verify the accuracy of the numerical simulation results and further optimize the model parameters. At the same time, the adaptability and stability of each scheme in diverse geological environments will be evaluated.  
Conceptualization, Y.L. ([PERSON]) and L.H.; methodology, X.T.; software, Y.X.; validation, W.K. and X.T.; formal analysis, Y.L. ([PERSON]); investigation, L.G.; resources; data curation, X.T.; writing--original draft preparation, X.T.; writing--review and editing, L.G.; visualization, L.H.; supervision, Y.L. ([PERSON]); project administration, Y.L. ([PERSON]); funding acquisition, L.G. All authors have read and agreed to the published version of the manuscript.  
This research was funded by National Natural Science Foundation of China, grant number 20242 BAB204095.  
The data presented in this study are available on request from the corresponding author (due to the difficulty in coordinating the data set, this article does not share the corresponding data set).  
Author [PERSON] was employed by the company Hangzhou Nanpai Water Conservancy Development 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.
# Integrity Monitoring of PPP-RTK Positioning: Part II: LEO Augmentation
## 4 LEO Augmentation
### Network Processing  
Before the user processing, the network corrections, i.e., the satellite clocks, satellite phase biases and ionospheric delays should be available from a network processing using L1/L5 observations from a four-constellation scenario (GPS/Galileo/BDS/LEO). The settings of the user processing are introduced at the beginning of Section 4.  
In this contribution, the network corrections are assumed to be generated with all four constellations and with the PAR enabled. Compared with the three-constellation scenario of GPS/Galileo/BDS, the precision improvements are not significant in the combined network corrections when adding the LEO constellation, as new satellites mainly benefit the parameters that are commonly estimated for all constellations, i.e., the ZTDs in our case, but not the satellite-specific network corrections.  
Recall that the considered LEO constellation broadcast code and carrier-phase observations that are interoperable with GNSS observations. With the PAR enabled for the four-constellation processing and with the ambiguities resolved constellation by constellation, as shown in Figure 9 for Network 1, the fix rate of the LEO satellite carrier-phase ambiguities that pass the success rate of 99.99% and get validated with the ratio test are shown to be lower than those of the other three GNSSs. This is related to the higher portion of the low elevation LEO satellites (see Figure 5). After the sharp increase within the first several minutes, the ambiguity fix rate of the LEO satellites remains at about 80% to 100%. This also applies to the Networks 2 and 3, which have larger sizes. Note that with the LAMBDA method, the ambiguities are first decorrelated with a transformation matrix before being resolved. The decorrelated ambiguities are thus linear combinations of the original ambiguities. With the decorrelated ambiguities successfully fixed to integers, they are transformed back to their original forms. As such, one unsolved decorrelated ambiguity could influence several ambiguities in their original forms. The fix rate shown in Figure 9 refers to the number of the fixed decorrelated ambiguities divided by the total number of the decorrelated ambiguities.
# EEG Channel Selection for Stroke Patient Rehabilitation Using BAT Optimizer
## 4 Proposed Method
### Phase V: Classification  
A KNN classifier is used in this work. In this proposed method, the dataset is split into 60% training, 20% validation, and 20% testing.
## 3 Material and Method
### Sieve Analysis  
Commonly, two distinct classification systems are normally used, these methods include the American Association of State Highway and Transportation Officials (AASHTO) and the Unified Soil Classification System (USCS) [27]. In this paper, the American Association of State Highway and Transportation Officials (AASHTO) was used. Particle size analysis (also known as sieve analysis) was carried out to classify the soil materials, determine their textures, and estimate the size of the grains. The latter is known to greatly influence the behavior of the soil mass; hence, its determination. The following apparatuses were used: a stack of sieves with the pan at the bottom and a top cover, a Sartorius balance accurate to within 0.01 g, a mechanical sieve shaker, a plate, and the Vacutec drying oven. To determine the grain size distribution, the samples were placed in the Vacutec oven and dried overnight. The dried soil was sieved through a stack of sieves placed on the mechanical shaker Sieves were arranged from top to bottom starting with coarser and ending with a smaller opening. The amount retained on each sieve was collected and weighed. This was later used to calculate the fraction of material passing each sieve as a percentage of the total sample being sieved.
# Elimination of the Solid Graininess Issue with Different Micro-Pattern Structures at Flexo Printing
## 2 Materials and Methods
### Printing  
In these tests performed on the Omet XFlex X4 press (Omet, Lecco, Italy), Flint Group Flexocure Force UV-cured ink cyan color was used during the tests. Cyan was chosen in this test because K is often used for the shadows. Yellow is a color in which we cannot see details. We could use cyan or magenta in the CMYK process color system. Anilox was Harper, screen ruling was 375 L/cm, and a cell volume of 3.1 cm\({}^{2}\)/m\({}^{3}\) was used. Tesa Softprint(r) Steelmaster open-cell foam tapes were used as plate-mounting tapes. The thickness of the mounting tape is 550 um. Moreover, Tesa 72,022 medium-soft and Tesa 72,026 medium-hard tapes were printed. PVC and PET substrates are used.  
Ink type and viscosity, anilox roller, printing pressure, and printing speed were adjusted at the same values in all test prints. All test samples are taken for measuring after printing 100 m (after print setup).  
Printing specifications are as follows:  
* Flexo press: Omet XFlex X4
* Printing Speed: 80 m/min;
* Flexo ink: Flint Group Flexocure Force UV cyan;
* UV Curing: UV Lamp, 600 WPI output power (Watts Per Inch);
* Printing width: 330 mm;
* Printing length: 419 mm;
* Anilox line count: 375 L/cm (950 lpi);
* Anilox cell volume: 3.1 BCM (Billion Cubic Microns);
* Plate mounting tape: Tesa 72,022 medium soft, Tesa 72,026 medium hard, 550 um thickness;
* Substrates: PVC (polyvinyl chloride) film and PET (polyethylene terephthalate) film. Pre-treatment applied PET surface energy 42 dynes/cm and PVC film surface energy of 46 dynes/cm. Substrate specifications:
* PVC: White monomeric, plasticized PVC film. Basis weight 112 g/m\({}^{2}\) (ISO 536) [18], caliper 84 um (ISO 534) [19].
* PET: Clear PET film. Basis weight 105 g/m\({}^{2}\) (ISO 536), caliper 75 um (ISO 534).  
Ink mixture: Tripropylene glycol diacrylate, poropylidynetrimethanol, ethoxylated esters with acrylic acid, 4,_A_'isopropylidenediphenol, oligomeric reaction products with 1-chloro-2,3-epoxypropane, esters with acrylic acid, 2-propenoic acid, 1,1'-(1,6-hexanediolyl) ester, 2-propenoic acid, reaction products with pentaerythnitol exanthylene diacrylate [20].
# Phase-Modulated Continuous-Wave Coherent Ranging Method and Anti-Interference Evaluation
## 3 Ranging Experiments
In order to demonstrate the validation of the PhMCW ranging method, we built a PhMCW LiDAR by mounting the collimator, shown in Figure 2, on a rotational base, and the laser beam direction is mechanically steered horizontally. Due to the narrow width of the clean room's corridor, the scanning angle is thus varied from \(-2^{\circ}\) to \(-2^{\circ}\) with a step of \(0.5^{\circ}\). Figure 6a gives a picture of the experimental scene, showing targets consisting of a diffused reflection board, laboratory doors, and a researcher at approximate distances of 15 m, 28 m, and 5 m, respectively. The measured results are shown in Figure 6b for average target distances of 15.13 m, 27.85 m, and 5.03 m, respectively. The measured distances are in good agreement with the actual distances. Figure 4: (**a**–**f**) Distribution figures of the ranging results at actual distances of 5.025 m, 10.09 m, 14.99 m, 19.96 m, 24.983 m, 50.179 m, respectively. Orange lines indicate Gaussian fits.
# Seismic Response Analysis of Multi-Story Steel Frames Using BRB and SCB Hybrid Bracing System
## 8 Conclusions  
BRBFs tend to accumulate excessive residual deformation after earthquakes, which may prohibit the repairing work and cause long-term business downtime after earthquakes. On the other hand, SCBs are known for their excellent capability of recovering deformation. In order to address the problem for conventional BRBFs, this paper suggested using BRBs and SCBs together to form a hybrid  
Figure 9: Seismic demands under the ground motion suite: (**a**) peak inter-story drift ratio; (**b**) residual inter-story drift ratio; and (**c**) peak floor accelerations.  
bracing system. The proposed idea essentially combined the energy dissipation capacity of BRBs and the recentering capability of SCBs, which has never been reported in prior studies. The main assumption made in this analysis was that the fracture problem of braces could be avoided, which is also widely accepted in peer studies [6; 13; 14; 15]. Thus, authors should understand current results with cautions. To validate the proposed methodology, intensive seismic analyses at the DBE seismic hazard level were conducted on six-story framing structures and the following conclusions can be obtained:  
1. When the SCBs were installed to replace BRBs at certain stories, the global energy dissipation capacity will be deteriorated while the recentering capability was enhanced, according to the cyclic pushover results.
2. The hybrid bracing configurations that use SCBs and BRBs in alternative stories were suggested, considering such a placement reduced the maximum and residual story drift ratios by approximately 2% and 65%, respectively, compared with the pure BRBF.
3. Although the residual deformation cannot be completely eliminated by using the hybrid bracing system, it was well reduced to approximately 0.1%, which is small enough to carry out economical reparability.
4. The concept presented in the paper can shed light on the cases when different dissipative devices are used or when different structural typologies are considered.  
Conceptualization: R.C., D.H., and C.Q.; methodology: R.C. and C.Q.; software: R.C., C.Q., and D.H.; validation: R.C. and C.Q.; formal analysis: C.Q.; investigation: R.C. and C.Q.; resources: R.C., D.H., and C.Q.; data curation: D.H. and C.Q.; writing--original draft preparation: R.C. and D.H.; writing--review and editing; C.Q.; visualization: R.C., D.H., and C.Q.; supervision: R.C. and C.Q.; project administration: R.C. and D.H.; funding acquisition: R.C., D.H., and C.Q. All authors have read and agreed to the published version of the manuscript.  
This research was funded by National Natural Science Foundation of China, grant number 51808317 and 51409045.  
The authors declare no conflict of interest.