esa-sceva/satcom-chunk-collection huggingface dataset:
###### Abstract  
A new compact UWB multiple-input-multiple-output (MIMO) antenna is presented in this paper. The proposed antenna, with a compact size of 30 \(\times\) 20 \(\times\) 1.6 mm\({}^{3}\), consists of a two-element microstrip line-fed pentagonal-shaped patch associated with a parasitic element and a partial ground plane. Three complementary split-ring resonator (CSRR) structures are integrated into the defected ground with the aims of reducing the mutual coupling and enhancing the bandwidth. A UWB impedance bandwidth is achieved covering the FCC band (3.1-10.6 GHz), corresponding to a reflection coefficient below \(-\)10 dB and a reduced mutual coupling below \(-\)22 dB. Additionally, acceptable limits of the diversity performance parameters are obtained. Furthermore, all the simulated outcomes of the suggested antenna are convenient for UWB-MIMO wireless applications. Measures carried out on the fabricated prototype of the antenna demonstrate good agreement between both the simulation and measurement results of the optimized two-port MIMO antenna.  
compact; UWB-MIMO; pentagonal patch; parasitic element; CSRR; defected ground pacs: 12.4852. +
Footnote †: journal: Electronics Letters
## 6 Experimental Simulations
### Picking
#### 6.1.5 Time Performance Analysis
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multicolumn{2}{c}{Order 1} & \multicolumn{4}{c}{Order 2} & \multicolumn{4}{c}{Order 3} & \multicolumn{4}{c}{Order 4} & \multicolumn{4}{c}{Order 5} \\ \hline \(t_{ij}\) & Zone & _PC_ & \(t_{ij}\) & Zone & _PC_ & \(t_{ij}\) & Zone & _PC_ & \(t_{ij}\) & Zone & _PC_ & \(t_{ij}\) & Zone & _PC_ \\ \hline / & 1 & / & / & 1 & / & / & 1 & / & 1 & / & / & 1 & / \\
47.73 & 10 & 4 & 47.73 & 10 & 4 & 47.73 & 10 & 4 & 47.73 & 10 & 4 & 47.73 & 10 & 4 \\
16.47 & 11 & 4 & 16.47 & 11 & 4 & 16.47 & 11 & 4 & 16.47 & 11 & 4 & 16.47 & 11 & 4 \\
25.92 & 12 & 4-3 & 25.92 & 12 & 4-3 & 25.92 & 12 & 4-3 & 25.92 & 12 & 4-3 & 25.92 & 12 & 4-3 \\
42.21 & 6 & 3 & 25.92 & 11 & 3 & 25.92 & 11 & 3 & 29.46 & 10 & 3-2 & 25.92 & 11 & 3 \\
31.76 & 3 & 3 & 16.47 & 10 & 3-2 & 16.47 & 10 & 3-2 & 38.82 & 3 & 2 & 16.47 & 10 & 3-2 \\
38.82 & 10 & 3-2 & 23.53 & 7 & 2 & 38.82 & 3 & 2 & 68.28 & 15 & & 23.53 & 7 & 2 \\
29.46 & 15 & & 28.24 & 3 & 2-1 & 42.35 & 11 & 1 & & & & 28.24 & 3 & 2-1 \\  & & & 31.76 & 6 & 1 & 25.92 & 15 & & & & & 42.35 & 11 & 1 \\  & & & 56.51 & 15 & & & & & & & & 25.92 & 15 & \\ \hline \multicolumn{2}{c}{232.38 s} & \multicolumn{2}{c}{272.56 s} & \multicolumn{2}{c}{239.62 s} & \multicolumn{2}{c}{226.68 s} & \multicolumn{2}{c}{252.56 s} \\ \hline \multicolumn{2}{c}{Order 6} & \multicolumn{4}{c}{Order 7} & \multicolumn{4}{c}{Order 8} & \multicolumn{4}{c}{Order 9} & \multicolumn{4}{c}{Order 10} \\ \hline \(t_{ij}\) & Zone & _PC_ & \(t_{ij}\) & Zone & _PC_ & \(t_{ij}\) & Zone & _PC_ & \(t_{ij}\) & Zone & _PC_ \\ \hline / & 1 & / & / & 1 & / & / & 1 & / & / & 1 & / & 1 & / \\
51.26 & 11 & 4 & 47.73 & 10 & 4 & 39.84 & 3 & 4-3 & 47.73 & 10 & 4 & 40.67 & 6 & 4 \\
25.92 & 12 & 4-3 & 16.47 & 11 & 4 & 24.26 & 2 & 3 & 16.47 & 11 & 4 & 23.53 & 9 & 4 \\
25.92 & 11 & 3 & 25.92 & 12 & 3 & 25.09 & 6 & 3 & 25.92 & 12 & 4-3 & 20.00 & 11 & 4-3 \\
16.47 & 10 & 3-2 & 29.46 & 10 & 3 & 20.00 & 8 & 3 & 25.92 & 11 & 3 & 20.00 & 9 & 3 \\
16.47 & 9 & 2 & 38.82 & 3 & 3-2 & 16.47 & 9 & 3-2 & 16.47 & 10 & 3 & 16.47 & 8 & 3 \\
23.53 & 6 & 2 & 42.35 & 11 & 2-1 & 16.47 & 8 & 2 & 47.73 & 1 & 3 & 25.09 & 2 & 3 \\
31.76 & 3 & 2-1 & 42.35 & 3 & 1 & 31.76 & 3 & 2-1 & 39.84 & 3 & 3-2 & 24.26 & 3 & 3-2 \\
31.76 & 6 & 1 & 24.26 & 2 & 1 & 68.28 & 15 & & 31.76 & 6 & 2 & 31.76 & 6 & 2 \\
56.51 & 15 & & 61.60 & 15 & & & & & & 23.53 & 9 & 2-1 & 20.00 & 8 & 2 \\  & & & & & & & & & & 32.99 & 15 & & 16.47 & 9 & 2 \\  & & & & & & & & & & & 35.29 & 3 & 1 \\  & & & & & & & & & & & 68.28 & 15 & \\ \hline \multicolumn{2}{c}{279.62 s} & \multicolumn{2}{c}{328.98 s} & \multicolumn{2}{c}{242.17 s} & \multicolumn{2}{c}{308.37 s} & \multicolumn{2}{c}{341.83 s} \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Simulation of travel times for 10 BOPS orders when the Relaxed SOP optimization is implemented. SOP can possibly be regained while considering packaging time as well. Packing the products while they are being picked may save time, but the more constraining SOP cannot accomplish this due to the significant difference.
## 6 Network Architectures for IEC61850-90-5 Multicast over Public WAN  
As was discussed in Section 4.3, R-SV/R-GOOSE communication over WAN can be cost-efficiently carried out by utilizing the existing public IP network and infrastructure. This section proposes two Point-to-Multipoint (P2M) architectures for multicast communication of R-SV/R-GOOSE over public WAN. P2M architecture can be used in multiple scenarios in which R-SV/R-GOOSE messages must be sent from one location to several locations. For example, from one substation to multiple substations, from one substation to other substations and a control center, from one microgrid to multiple microgrids, etc.  
Figure 16: Non-secured R-SV/R-GOOSE messages encapsulated by GRE and secured by ESP over IPsec tunnel between edge routers.
## 4 Discussion of Results
### Regional Scale Analysis  
#### 4.2.1 Ecological Degradation Effects in Rivers State Region  
An examination of Figure 7 reveals several epicentres of ecological degradation in the Rivers State region, most likely driven by compound oil spills over this time. From a regional scale linear regression fit in Figure 8, we can estimate that the total bare land area is increasing at a rate of 5644 hectares/year. Although it is unlikely that it will continue to expand at this rate over the next 25 years, to eradicate the remaining 130,000 hectares of mangrove area classified by our analysis in this region, the threat of significant, irreversible damage is clear unless more effective remediation efforts are implemented, or the rate of spread is reduced.  
Ongoing dredging and channel widening operations in the region--intended to improve accessibility to oil reserve zones--have led to the classification of certain water bodies as bare on the banks. This misclassification occurs due to sulfidic dredged materials being dumped along the banks, resulting in mangrove suffocation through soil acidification and heavy metal pollution [40]. The presence of some of these waterbodies, previously absent in the initial mask, has become more apparent as vegetation density decreases. Despite these activities, the final waterbody mask was deemed sufficient for the objectives of this study as adding a water class would reduce class certainty.  
Figure 6: Model confusion matrix for validation set. Values are normalised to show the proportion accurately classified in each class.  
Figure 7: Annual post-HMM classification of Rivers State region for 2016, 2020, and 2023. Cropland, grassland, permanent water bodies, and built-up areas are all masked out in white. The classification results shown here highlight the spatial distribution of land degradation, with several epicentres of ecological deterioration becoming increasingly apparent.
## 3 Analytical Expressions
### General Structure of the Adopted WuRx Circuit  
The general structure of a WuRx is shown in Figure 3, which is composed of antenna, RF bandpass filter, impedance matching, envelope detector, LF-amplifier, and LF wake-up receiver IC.  
To reduce interference with other radios and to avoid disturbances from different frequency bands, a bandpass filter is used to let the input signals of a certain frequency range pass. The Schottky diodes after the filter demodulate the incoming wake-up signal. For encoding the WuPt, a low-power microcontroller [34; 35], flip-flops [36], or preamble detector [37] are employed. To identify the intended received signal and prevent false wake-ups, the WuPt can contain an address field with a node ID. After address matching, the decoder generates an interrupt to the main MCU.  
As shown in Figure 3, the architectures of OA and BJT as LF-amplifier approach consist of a bandpass filter for 868 MHz, a matching network, the detector diodes, and the low-power LF wake-up receiver IC for address matching of the wake-up signal. After the  
Figure 3: Block diagram of the WuRx architecture.  
Figure 2: Comparison of SoA WuRx architectures.  
detector diodes, the LF signal is amplified by an LF-amplifier circuit. To identify the right signal, an address decoder is used. Usually, the AS3933 is employed as a decoder and is able to detect signals with a minimum voltage level of at least 80 uVRMS. This means that the AS3933 limits the overall sensitivity of the WuRx. For this reason, amplification has to be implemented in order to increase the sensitivity of the whole receiver to the minimum detectable voltage level. The AS3933 chip analyses the wake-up signal in order to check the validity of the message and the matching to the predefined address. In case of validation and matching, the MCU is woken up by an interrupt of the LF wake-up receiver chip.  
The main differences between these both architectures are concerning the amplification stage. The first architecture uses a transistor-based amplifier (named as BJT) and the second one uses operational amplifier in a transimpedance amplifier configuration (named as TIA).
## 3 Stability Analysis and Discussion
### 2-DOF Model of VHCVSS  
For a milling process, when the contained cutter is regarded as a cantilever beam but the workpiece is assumed to be absolute rigidity, the vibration of the tool has to be considered but that of the workpiece. Then, the associated system equation can be simplified and defined by the DDE with 2-DOF. Compared with the 1-DOF system in Section 3.1, the 2-DOF one is a more universal and general expression, so more attentions are paid on it for the existing research.
# Fewer Dimensions for Higher Thermal Performance: A Review on 2D Nanofluids
## 3 Application of 2D Nanofluids
### Cold Thermal Energy Storage  
Cold thermal energy processes are pivotal in certain applications, such as the thermal energy management of air-conditioning systems in large buildings. Two-dimensional nanofluids with high thermal storage capabilities provided mainly by their enhanced latent heat capacity, which is the case in Gr 2D nanofluids, are suitable for such heat storage purposes. The hybrid formulations composed by 2D nanofluids and phase change materials have already been demonstrated as strong candidates to successfully store cold thermal energy. In subzero cold thermal energy storage systems, it is current practice to explore ethylene glycol nanofluids as phase change materials. These nanofluids normally exhibit a large supercooling degree, an extended freezing time, a poor storage capacity, and poor colloidal stability. To overcome these limitations, Zhang et al. [157] prepared stable nanofluids composed of 2D GO nanosheets suspended in ethylene glycol to evaluate their suitability to operate as performant subzero cold thermal energy storage phase-change media. The authors stated that the uniformly dispersed monolayer nanosheets of GO reduced the supercooling degree, accelerated the charging and discharging processes, and retained the enhanced specific heat of the phase change nanofluids. Furthermore, the incorporated nanosheets provided heterogeneous nucleation points, enabling the formation of crystals and reducing the freezing time and supercooling degree. Particularly, the supercooling degree was found to be reduced by 87.2%, the freezing period was reduced by 78.2% (in reference to those of the pure base fluid), and the latent heat was maintained at 98.5%. The synthesized nanofluids increased the TC up to 12.1% compared with that of the ethylene glycol itself. Moreover, the nanofluids maintained their thermal stability after being subjected to 50 cycles of freezing/melting, which guarantees a consistent performance as a cold thermal energy storage fluid during extended working periods. In sum, the improved thermophysical characteristics, together with the facile method of preparation and low loading needs, makes GO nanosheet ethylene glycol nanofluids suitable for use in high-performance subzero phase change cold thermal energy storage systems. Nonetheless, there is a lack of research on the development of effective thermal energy management with rapid charging modes using 2D nanofluids. The energy saving potential of the combined use of 2D nanofluids and phase change materials during the freezing process should be addressed in further research. Additionally, there is a literature gap on the impact of 2D nanofluids on the rate of supercooling and freezing. Moreover, there are few experimental or numerical works on the 2D nanofluid-based storage unit potential in efficient chiller-based air-conditioning systems for the cooling of large buildings.
# Estimation of Optimal Speed Limits for Urban Roads Using Traffic Information Big Data
## 2 Theory and Prior Studies
### Speed Limit Estimation Method
#### 2.2.3 Expert System Approach  
This approach determines the speed limit with a computer program using the knowledge base and an inference procedure that simulates the behaviors and judgment of experts. It was first implemented by the Victoria State in Australia in 1987 to create a unified, consistent approach to determining section speed limits.  
The U.S. uses an expert system (USLIMITS2) [12] to determine the optimal speed limits in \"speed zones\". As a web-based expert advisor system, when data are provided through a user program, it outputs the recommended speed limit and cautions for the given conditions, thus playing an assistive role in setting an appropriate speed limit.
# Effect of Subglottic Stenosis on Expiratory Sound Using Direct Noise Calculation
## 4 Summary and Discussion  
### Tonal Sound Mechanisms  
For airways with SGS, the primary source of tonal sound generation during expiration was the jet-obstacle system in which the SGS produced the jet and the vocal folds function as the obstacle. Additionally, a few resonators were identified that coupled with the jet-obstacle system to form a strong excitation of pure tones, including the vocal tract (from glottis to mouth) and the extended tract (from the SGS to the mouth). The purity and the frequency of the tones depended on the coupling between the jet-obstacle system and the resonator, which was affected by the flowrate in a nonlinear fashion due to possible changes of acoustic mode and vortex mode.  
Pure but weak hole tones were observed, starting from a medium SGS severity (>50%) at low flowrates. The frequency of the tones was not affected by acoustic feedback from the tract, which was also weak due to the low sound level. The frequency of the hole tones tended to be relatively low.  
As the flowrate and the sound pressure level increased, the acoustic feedback of the resonators had stronger influence on the SGS jet. However, resonance only occurred in cases with 96% severity, in which the frequency of the SGS jet locked to the excited harmonic of the resonator. For medium to high severity (84% to 91%), while the harmonics of the resonator were present, the spectra were cluttered with various peaks. This could be due to two factors: (1) the acoustic feedback from the tract was still not strong enough to lock the hole tone system to the same frequency, (2) a compatible coupling could not be established under the specific geometric configuration.  
A particular interesting configuration was noticed where the closed-open extended tract and the open-open vocal tract had overlapping harmonics. A pure tone could be excited at the overlapping frequency under a flowrate favorable to the hole tone system. In this case, the distance of the SGS could be inferred from the frequency.  
When constricting the glottis to a very small opening size, the harmonics of the closed-open vocal tract became dominant, resulting in a higher overall SPL and pitch. Again, the purity of the tones depended on the coupling between the hole tone system and the vocal tract. At high severity, the cavity between the SGS and the vocal folds could form a Helmholtz resonator, which, on very rare occasions, could lock the excited tone to the Helmholtz resonance frequency.  
Figure 11: Effect of stenosis distance on the expiratory sound. Comparison is made among cases with the constricted glottis but different SGS distances.
## 1 Introduction  
Gallium nitride (GaN) and its related III-nitride materials are excellent wide direct band-gap (3.4 eV) semiconductors due to their potential properties of high saturation velocity in an electric field, high breakdown electric field, and electron mobility--all of which are necessary for the development of next-generation devices and applications that are high frequency, highly efficient, and can effectively power switching devices [1; 2; 3]. However, due to the lack of suitable native or lattice-matched substrates, GaN epilvers are usually grown on sapphire, SiC, and Si substrates. This presents a serious problem, as a high defect density and a large biaxial stress in the heteroepitaxy of the GaN epilayers are generated by mismatches in the lattice structure and thermal expansion coefficients between the epilayers and the Si substrate. These growth-induced defects (such as threading dislocations, stacking faults, voids, and point defects) limit the performance and reliability of GaN-based devices [4; 5; 6]. ZnO-related materials may be closely lattice-matched with GaN, but the drawback of the ZnO single crystalline wafer is that it is still expensive [7]. Substrates that produce a low density of defects present the most effective possible approach for reducing defects in epitaxial films. The most widely used methods for growingGaN with low defect density are hydride vapor phase epitaxy (HVPE) and metalorganic chemical vapor deposition (MOCVD) [8; 9]. GaN thin films with high-quality and low-density of defects can also be grown by ion-beam assisted MBE [10; 11]. The reaction chamber in an HVPE system is often made of quartz, which is not operational under high temperature. An MOCVD system requires a high-temperature growth process, which consumes considerable electric power and thereby produces high running costs and the possibility of air pollution due to the toxicity of the metal-organic chemicals in the precursor gas. Pulsed laser deposition (PLD) is a promising technique that can address these problems [12; 13; 14]. PLD is interesting, as it allows for in situ processing of the multilayer structure via multiple targets, stoichiometric transfer deposition from the target to the substrate, flexible doping options for complex compositions, and a highly directionally distributed energetic precursor produced by the laser ablation of a target. Most discussions on PLD focus on studying the influence of growth conditions on the properties of GaN films [15; 16; 17; 18; 19]. Several previous studies have reported how PLD enables the growth of high-quality III-nitrides on other substrates [20; 21; 22; 23; 24]. Since the considerable scale and production cost of native GaN substrates would be too much, GaN templates on foreign substrates are good choices for the heteroepitaxial deposition of GaN-based devices. In this study, the crystalline quality, surface morphology, optoelectronic and structural properties related to GaN thick film grown on different substrates as a GaN templates through high-temperature PLD are characterized and compared.
# Neural PD Controller for an Unmanned Aerial Vehicle Trained with Extended Kalman Filter
## 7 Results  
The platform selected to test the algorithm was the Parrot Ar.Drone 2.0, which is a quadrotor equipped with a 3-axis gyroscope, 3-axis accelerometer, a magnetic compass, an ultrasound altimeter, one camera looking in \(x\) direction and another camera looking downward. For these experiments, the camera looking forward was used; it has a field of view of 92\({}^{\circ}\) and a resolution of 640 \(\times\) 360. Its video is streamed at 30 fps to the ground station. Sensor measurements of the Ar.Drone 2.0 can be sent to the ground station at a frequency of 200 Hz; however, due to integration of the ANN training, control, localization and mapping, this transmission rate is decreased to 30 Hz in the following experiments.
## 4 Assimilation and Impact of GNSS-R Data  
Compared to atmospheric profiles provided by GNSS RO, ocean surface winds observed by GNSS-R are more visually interpretable and thus can provide direct information on the location, intensity, and structure of TCs. Therefore, GNSS-R wind data can be used to directly monitor TCs [83, 84, 85]. To improve TC forecasts of NWP models, GNSS-R wind observations need to be assimilated into NWP models. GNSS-R wind speeds can modify the first guess through assimilation and then improve forecasting. NASA's CYGNSS constellation, consisting of eight satellites, aims to use GNSS-R ocean surface wind observations to improve the trajectory and intensity forecasts of TCs. This assimilation can significantly impact the accuracy of weather forecasts and climate models [79, 80, 81, 82, 83]. By integrating these data, we can more accurately understand and predict extreme weather events, like TCs, thereby enhancing the reliability of forecasts.
## Materials and Methods  
### Study Area  
The study area is in the Andean high plateau, Antofagasta Region, Chile, at approximately 4000 m.a.s.l. southeast of the Salar de Atacama. Access to the area is from San Pedro de Atacama village taking the CH-23 route towards the International Sico Pass 148 km away. The Salar de Aguas Calientes Sur has an approximate area of 476 km\({}^{2}\), and it is located within the Salar de Talar and the Purisunchi Sub-basin, between Salar de Capur to the west and Laguna Tuyajto to the east (Figure 1). The type of basin is endorheic and intra-volcanic.  
Figure 1: Study area: (**a**) Location within Chile, (**b**) Sentinel 1B image, VV polarization in decibels (dB), ascending pass, acquired on 3 April 2018, indicating the location and contour of the salar in yellow. The sub-basin has an area of 671,576 km\({}^{2}\). From: [[http://www.geoportal.cl](http://www.geoportal.cl)]([http://www.geoportal.cl](http://www.geoportal.cl)). (Coordinate system: GCS_WGS_1984).  
To the north and center of the salar are some ignimbritic deposits (Patao Ignimbrite) considered as host rock of the salar from the Pliocene age [19]. In general, the pan crust surface in the center of the salar has no vegetation, whereas the northern, southern, and salar margins are sparsely covered with patchy bushes and spring-feed vegetation related to shallow lakes. The most abundant evaporitic minerals found in the salt flat are gypsum and halite.
## 2 Ring Oscillator Based on a Cascade of Three Current Mode Logic (CML) Buffer
### Ring Oscillator Layout Design  
The complete layout of the RO-VCO designed in 65 nm CMOS bulk-silicon technology is shown in Figure 4. The simple current mirror, in the bottom side, and the three source-coupled pairs are designed, adopting the common centroid technique to increase matching. All the gate terminals are turned in the same way so that the current flows in the same direction, and the space between instances is the minimum allowed by technology rules. A trade-off between metal width and length is made to prevent the electro-migration phenomena due to high current density. Moreover, alternate layers perpendicular to each other are drawn to minimize parasitic capacitances that lead to a frequency reduction. The total layout area of the proposed RO-VCO is \(249\times 86~{}\upmu\)m\({}^{2}\).  
Figure 3: Varactor capacitance vs. control voltage for RO-VCO (**a**) and LC-VCO (**b**), different corner cases. RO, Ring Oscillator; VCO, Voltage Controlled Oscillator.  
Figure 2: Circuit schematic of the single-stage, based on a Current Mode Logic (CML) buffer, of the ring oscillator and a couple of varactors connected at the two outputs.