esa-sceva/satcom-chunk-collection huggingface dataset:
# Design of a New Supersonic Shock Wave Generator and Application in Power Generation
## 4 Design of a Power Generation System Driven by Supersonic Shock Waves
### Power Generation Experiments and Analysis
For example, when \(S_{min}=1200\) rpm, the \(I_{p\text{-}avg}\) and \(E_{p\text{-}avg}\) generated by turning on one, two, and three bulbs are 51.33, 98.63, and 143.26 (mA) and 1375.13, 2514.68, and 3501.05 (mW), respectively, and their ratios are all about 1:2:3. There is a similar ratio when \(S_{min}=1500\) rpm. 7. When users turn on a light bulb, its average load resistance \(R_{l\text{-}avg\text{-}1}\) is calculated as follows: \[R_{l\text{-}avg\text{-}1}=V_{p\text{-}avg\text{-}1}/I_{p\text{-}avg\text{-}1 }=26.79/0.05133=521.92\Omega\text{ (for }S_{min}=1200\text{ rpm)}\] \[R_{l\text{-}avg\text{-}1}=V_{p\text{-}avg\text{-}1}/I_{p\text{-}avg\text{-}1 }=38.85/0.07744=521.89\Omega\text{ (for }S_{min}=1500\text{ rpm)}\]
8. When turning on two or three bulbs connected in parallel, if \(R_{1}\), \(R_{2}\), and \(R_{3}\) are bulb resistors, \(R_{l2}\) and \(R_{l3}\) represent the load resistance of two bulbs and three bulbs connected in parallel. We can express the load resistors \(R_{l2}\) and \(R_{l3}\) as Expressions (30) and (31) (since \(R_{1}=R_{2}=R_{3}\)): \[\frac{V}{R_{l2}}=\frac{V}{R_{1}}+\frac{V}{R_{2}}=\frac{2V}{R_{1}}\quad..\;R_{ l2}=\frac{R_{1}}{2}\] (30) \[\frac{V}{R_{l3}}=\frac{V}{R_{1}}+\frac{V}{R_{2}}+\frac{V}{R_{3}}=\frac{3V}{R_{1 }}\quad..\;R_{l3}=\frac{R_{1}}{3}\] (31) The average load resistance \(R_{l\text{-}avg\text{-}2}\) and \(R_{l\text{-}avg\text{-}3}\) are calculated as follows: For \(S_{min}=1200\) rpm, \[R_{l\text{-}avg\text{-}2}=V_{p\text{-}avg\text{-}2}/I_{p\text{-}avg\text{-}2 }=25.46/0.09863=258.14\Omega\approx R_{l\text{-}avg\text{-}1}/2=260.96\Omega\] \[R_{l\text{-}avg\text{-}3}=V_{p\text{-}avg\text{-}3}/I_{p\text{-}avg\text{-}3 }=24.44/0.14326=170.60\Omega\approx R_{l\text{-}avg\text{-}1}/3=173.97\Omega\] For \(S_{min}=1500\) rpm, \[R_{l\text{-}avg\text{-}2}=V_{p\text{-}avg\text{-}2}/I_{p\text{-}avg\text{-}2 }=37.78/0.14524=260.12\Omega\approx R_{l\text{-}avg\text{-}1}/2=261.09\Omega\] \[R_{l\text{-}avg\text{-}3}=V_{p\text{-}avg\text{-}3}/I_{p\text{-}avg\text{-}3 }=36.64/0.21101=173.64\Omega\approx R_{l\text{-}avg\text{-}1}/3=174.06\Omega\] This calculation result is consistent with the relationship between Equations (30) and (31), showing that the average error of the monitoring results of this experiment is tiny. Therefore, \(V_{p}\), \(I_{p}\), and \(R_{l}\) monitored and calculated by the power generation experiments can all comply with the relevant circuit analysis laws for different numbers of parallel light bulb loads.
# Review on the Role of GNSS Meteorology in Monitoring Water Vapor for Atmospheric Physics
## 5 Impact of Water Vapor Variability on Meteorology and Climate
### Radiative Transfer Studies  
There has been recent interest in the role of water vapor in radiative balance, enhanced by the increase in water vapor data availability, with higher spatial and temporal resolution. [PERSON] et al. (2018) studied the short-wave effects of water vapor using 20 GNSS stations in the Iberian Peninsula as input to Santa Barbara's dissort radiative transfer model (SBDART). They found that the effect for cloudless skies followed an empirical power relation of the short-wave effect with IWV and the cosine of the solar zenith angle. An extended study ([PERSON], 2018), including short- and long-wave in seven selected stations, found that positive trends for long-wave (and total) water vapor effects could partially explain the well-known increase of surface air temperatures in the Iberian Peninsula, while the negative trend in the short-wave effect represented about a quarter of the contribution of aerosols to the so-called brightening effect.  
In a more practical fashion, GNSS data are also used for the modeling of atmospheric transmission. The PWV_KPNO python package ([PERSON], 2018) uses GNSS IWV data from the SuomiNet network for modeling atmospheric transmission function due to water vapor. The package interpolates IWV data from the GNSS stations to the desired position and then applies the MODTRAN model to obtain the atmospheric transmission.
# Chaos and Stability in a New Iterative Family for Solving Nonlinear Equations
## 3 Complex Dynamics Behavior
### Analysis of Critical Points  
We calculate the critical points of the rational operator \(R_{\alpha}(x)\) given in (30).  
**Proposition 4**.: _The critical points of \(R_{\alpha}(x)\) are the roots of the equation \(R_{\alpha}^{\prime}(x)=0\). That is, \(x=0\), \(x=\infty\) and the following free critical points:_  
* \(cr_{1}=-1\)_,_
* \(cr_{2}=-i\)_,_
* \(cr_{3}=i\)_, and_
* \(cr_{i}(\alpha)\) _that correspond to the 6 roots of polynomial_ \((6\alpha+30)x^{6}+(\alpha+103)x^{5}+(2\alpha+206)x^{4}+(-6\alpha+246)x^{3}+(2 \alpha+206)x^{2}+(\alpha+103)x+6\alpha+30\)_, where_ \(i=4,...,9\)_._ _The total number of different critical points varies with the value of_ \(\alpha\)_:_
* _If_ \(\alpha\in\mathbb{C}\) _and_ \(\alpha\
otin\{-77,-5,-1,1,5\}\)_, then_ \(R_{\alpha}(x)\) _has 11 critical points._
* _If_ \(\alpha\in\{-77,-5,-1\}\)_, then_ \(R_{\alpha}(x)\) _is simplified or reduced and has 9 critical points._
* _If_ \(\alpha\in\{1,5\}\)_, then_ \(R_{\alpha}(x)\) _is simplified and has 7 critical points._ _The pairs of conjugated free critical points, satisfying_ \(cr_{i}=\dfrac{1}{cr_{j}}\) _for_ \(i\
eq j\)_, are_ \(cr_{2}\) _and_ \(cr_{3}\)_,_ \(cr_{4}\) _and_ \(cr_{5}\)_,_ \(cr_{6}\) _and_ \(cr_{7}\)_, and_ \(cr_{8}\) _and_ \(cr_{9}\)_._  
From Proposition 4, we establish there is a minimum of 7 and a maximum of 11 critical points. Of these, 0 and \(\infty\) correspond to the roots of the original quadratic polynomial \(p(x)\). The free critical points \(cr_{1}=-1\), \(cr_{2}=-i\), and \(cr_{3}=i\) are pre-images of the strange fixed point \(ex_{1}=1\). Therefore, the stability of \(cr_{1}\), \(cr_{2}\), and \(cr_{3}\) will correspond to the stability of \(ex_{1}\) (see Section 3.2). Moreover, the dynamical study of the free critical points is reduced by a half because each pair of conjugated free critical points presents the same stability characteristics. This will be seen in Section 3.4.  
Figure 1: Stability surface of \(ex_{1}=1\) (in gray color, the complex area where the fixed point is repulsive, being attracting in the rest).  
Figure 2: Stability surfaces of 8 strange fixed points (in gray color, the complex area where each fixed point is repulsive, being attracting in the rest).
# Development and Assessment of a 4D Printing Technique for Space Applications
## 4 Discussion
### Derived Use-Case Scenarios in Spaccerrafts  
The application of self-activating hinges in spacecrafts, particularly in the context of deploying structures such as solar arrays, emerges as a promising use case. The unique combination of exceptional mechanical and chemical qualities of PEEK positions it as a viable material for spacecraft applications. Its resilience in extreme environmental conditions, including vacuum and radiation exposure, aligns with the rigorous demands of space missions.  
The observed SMEs of the 4D printed hinges exceeded the initial expectations. Achieving a 100% programming and recovery ratio with a recovery temperature of a minimum of 150 \({}^{\circ}\)C positions, indicates these hinges are robust components for self-deploying structures in space.The well-programmed hinges cover a full 180\({}^{\circ}\) range, making them versatile for a range of applications in spacecrafts. The geometry employed in this study serves as a baseline, acknowledging that adjustments may be necessary depending on the specific use case. A primary envisaged use case involves employing these self-activating hinges for solar arrays on spacecrafts. As solar arrays are exposed to solar radiation after deployment, the hinges autonomously facilitate the opening of the solar arrays, streamlining the deployment process.  
While the hinges demonstrate a passive activation temperature of 150 \({}^{\circ}\)C, achieving this temperature passively in space environments, especially in Earth orbiting satellites, proves challenging. In Lower Earth Orbit (LEO) or Geostationary Orbit (GEO), temperature ranges may not naturally reach the required 150 \({}^{\circ}\)C (refer to [25]). Potential solutions include incorporating PEEK as part of a partial-transition mechanism (PTM) (refer to [19]) in a multi material hinge or utilizing electromagnetic effects for controlled heating.  
The exploration of self-activating hinges in spacecrafts unveils exciting possibilities, with PEEK's material properties and the observed shape memory effects presenting a significant advancement in deployable structures for space applications.
# Performance Analysis of BDS-5G Combined Precise Point Positioning
## 3 Results and Discussion
### Static PPP
#### 3.2.2 Geometric Configuration  
Figures 7 and 8 show the convergence results for static PPP and tropospheric zenith wet delay in the XYZ directions for Scenes 1 and 2, respectively, with different colors representing the different geometric configurations involved in the PPP. Figure 9 shows how the mean convergence time and STD of the error varied over the six initializations per day.  
Figure 7: Convergence of different base station geometries for Scene 1, (**a**) X direction, (**b**) Y direction, (**c**) \(Z\) direction, (**d**) Zenith wet delay.  
Group B in the Y direction was 30.46% less than that of Group D, and the STD of Group C in the Z direction was 31.45% less than that of Group D. TheSTD in each dominant direction was less than 1 cm.  
Compared with Scene 1, the geometric configuration in Scene 2 had more significant advantages. In terms of convergence time, Groups A, B, C and Group D were able to converge in a few minutes in their respective dominant directions. In terms of the change in the STD of errors, the STD of Group A in the X direction was reduced by 70.48% compared with that of Group D, the STD of Group B in the Y direction was reduced by 48.76% compared with that of Group D, and the STD of Group C in the Z direction was reduced by 66.17% compared with that of Group D, and the reduction in the STD of the errors was greater than that of Scene 1. When the dominant configuration was involved in each direction, the convergence speed and accuracy of Scene 2, which had a smaller number of satellites, almost reached the same level as Scene 1.  
From this, we can see that the geometric configuration of 5G base stations has a great impact on the convergence of PPP in combined positioning. We can obtain very short convergence times and high-precision location information by deploying the advantageous base station configuration in the direction of the target.
# Machine Learning-Assisted Secure Random Communication System
## 3 Allied Concepts  
In this study, we investigate the integration of an ML algorithm with an RCS; it is therefore necessary to delve into the principles of the methods used. The proposed ML-RCS begins by harnessing the antipodal characteristics of the Sk\(\alpha\)S noise carrier signals for transmitting binary bits. Therefore, in this section, we first discuss the general structure of the \(\alpha\)-stable noise and its special cases. We train the data retrieved via the LR using the DT. To better understand the training and decision-making phases of DTs, we present them in detail and explain the variants of DTs utilized. We then explore the DT decisions obtained when dealing with the \(\alpha\)-stable noise signals.
###### Abstract  
We propose a novel design method for multi-focal metallic Fresnel zone plates (MFZPs), which exploits the phase selection rule by putting virtual point sources (VPSs) at the desired focal points distant to the MFZP plane. The phase distribution at the MFZP plane reciprocally formed by the VPSs was quantized in a binary manner based on the phase selection rule, thereby leading to a corresponding on-off amplitude pattern for the targeted MFZP. The resultant phase distribution was dependent on the complex amplitudes of the VPSs, so that they could be determined from the perspective of both multi-focal functionality and fabrication feasibility. As a typical example, we utilized the particle swarm optimization algorithm to determine them. Based on the proposed method, we designed and numerically analyzed two types of novel MFZPs--one for a monochromatic multi-focal application and the other for a multi-chromatic mono-focal application--verifying the effectiveness and validity of the proposed method. We also fabricated them onto Au-deposited glass substrates, using electron beam evaporation and a focused ion beam milling process. We experimentally characterized them and also verified that they successfully demonstrated their feasibilities. The former produced distinct hot spots at three different focal distances of 10, 15, and 20 \(\upmu\)m for monochromatic incidence at 650 nm, and the latter produced a single hot spot at a focal distance of 15 \(\upmu\)m for multi-chromatic incidence at 660, 532, and 473 nm. The experimental results were also in good agreement with their corresponding numerical results. We expect that both MFZPs will have various applications, such as laser micromachining, optical trapping, biomedical sensing, confocal collimation, achromatic optics, etc.  
l 2018 8, 449; doi:10.3390/app8030449
# Performance Evaluation Method for Intelligent Computing Components for Space Applications
## 3 Evaluation Method
### Typical Application Benchmarks in Space  
We define a set of benchmark testing methods that cover common typical applications in space missions. This article selects image calibration applications and AES encryption applications to construct the benchmark, reusing optimized parallel kernel implementation methods such as FFT and FIR filtering from the GPU4S benchmark.
# Cellulose Nanofibril (CNF) Films and Xylan from Hot Water Extracted Birch Kraft Pulps
## Materials and Methods
### Microscopic Imaging of CNF by SEM and AFM  
The extent of fibrillation in the CNF samples was investigated by microscopic observation of their micro- and nanofractions. For the microfraction, the CNF samples were diluted 50 times with Milli-Q water and drop-casted on a silicon wafer coated with polyethylenimine (PEI). Images of the samples were obtained with a scanning electron microscope (SEM; Merlin Field Emission (FE)-SEM, Carl Zeiss NTS GmbH, Oberkochen, Germany) after applying a gold-sputter coating (30 mA, 30 s). The accelerating voltage was kept constant at 3 kV with a grid current of 60 pA, and the pixel resolution was \(2048\times 1536\). The dimensions of the microfraction were determined from the SEM micrographs using the open-source image processing software ImageJ 1.5 lj8. For the nanofraction, the CNF samples were first diluted 10 times in Milli-Q water, sonicated for 10 min at 25% amplitude, and centrifuged at 10,400 rpm for 45 min. About 5 mL of the supernatant were then drop-casted on a PEI-coated silicon wafer. Images of the samples were obtained with an atomic force microscope (AFM; nano-TA scanning probe microscope, Anasys instruments, Santa Barbara, CA, USA). The height imaging was carried out in air with silicon cantilevers operating in tapping mode, with an image size of \(5\times 5\)\(\upmu\)m\({}^{2}\). From eachsample, three separate areas were imaged, and no other image processing than flattening was used. The AFM images were processed with Analysis studio software (Anasys instruments).
## 2 Multi-Hop Bent-Pipe LEO Satellite Constellation
### Antenna Design Challenge for Beam-Hopping  
The specific wavelength allocated to each service and the forwarding entry of each wavelength are determined by the wavelength routing algorithm [34; 35; 36]. The number of available wavelengths of each laser is limited. Once used up, the ISL can no longer serve new traffic, which may lead to call blocking. Therefore, the wavelength routing algorithms generally focus on minimizing the number of wavelengths used or minimizing the blocking rate.  
Flexible, high-gain broadband spot beam access, which allows users to customize their access on demand and is another technical approach for broadband internet satellites, requires precise beam aiming. Over 10 Gbps data transmission service can be achieved through the coverage of the spot beam. This makes it possible to integrate LEO satellite communications with 5G networks.  
As shown in Table 1, three representative large LEO satellite networks now in use all employ high-gain point beams [37; 38; 39]. The beam widths are all quite near to 1\({}^{\circ}\). In order to achieve full coverage, the pointing interval of the beam must be close to 1\({}^{\circ}\). The beam's control precision must be less than 1\({}^{\circ}\) if it is to achieve overlapping coverage. Such high precision control causes the design of the beam control components to face significant challenges. Additionally, broadband signal beamforming techniques must still be used because of the high accuracy standards to prevent the beam squint.  
Figure 3: Payload architecture.  
There are currently two main methods of achieving accurate beam pointing in broadband communications: digital delay lines and optical true delay lines. The digital delay line achieves delay compensation by sampling the signal with a high-speed ADC. OneWeb is currently working with Satisfy to launch a digital technology path payload [40]. The optical true delay line modulates the RF signal onto the optical carrier, based on the optical delay line or slow light effect, to create a true delay in the RF signal.
## 5 Experimental Method  
Figure 8 shows the fabricated macro-scale prototype of the proposed HEH and the experimental system. The substrate of the cantilever beam is made of Phosphor Bronze (ALB Copper Alloys Co., Ltd., Xiamen, China). It is sandwiched between two PZT-5H patches (Baoding Hongsheng Acoustics Electron Apparatus Co., Ltd., Baoding, China), which are connected in series. Two permanent magnets are NdFeB (Ningbo Hony Technology Co.,Ltd., Ningbo, China). They have opposite directions of magnetization. The magnetic proof mass is cylindrical. The magnet of the magnetic oscillator is a magnetic ring. It is attached to an aluminum rod, which is bolted on the frame. The rod is used to keep the magnet moving on the vertical direction. The copper wire coil (Changzhou Wujin Enameled Wire Factory Co., Ltd., Changzhou, China) is placed along the motion direction of the magnetic oscillator. The geometric and physical properties of the prototype are according to Table 1. The internal resistance of the coil is 240 \(\Omega\). The experimental system consists of an electromagnetic shaker (JZK-50) (Sinocera Piezotronics Inc., Yangzhou, China), a signal generator (DG-1022) (Rigol Technologies Inc., Beijing, China), a power amplifier (YE5874A) (Sinocera Piezotronics Inc., Yangzhou, China). The base excitation acceleration was measured by an accelerometer (YD64-310) (Qinhuangdao Xinheng Electronic Technology Co. Ltd., Qinhuangdao, China). The output voltage was continuously monitored by the oscilloscopes DS-5102 MA (Rigol Technologies Inc., Beijing, China) and TDS-1012C (Tektronix China Ltd., Shanghai, China).  
Upon the numerical simulation, the theoretical resonances of the piezoelectric and magnetic oscillators are about 26 Hz and 22 Hz, respectively. Thus, we sweep the excitation frequency from 16 to 32 Hz in the following experiments. The base excitation generated by the electromagnetic shaker is harmonic and the acceleration is set 2 m/s\({}^{2}\). The initial separation distance between two magnets \(d_{0}\) is 52.5 mm.  
In order to evaluate the performance of the proposed HEH, four different energy harvesters with single conversion mechanism were also developed and experimentally verified for comparison under the same excitation condition. When the induction coil around the magnetic oscillator is open-circuit, there will be no electromagnetic damping induced in the energy harvesting system. Accordingly, the HEH changes into a conventional multi-frequency PEH (MPEH) with magnetic oscillator, as reported in reference [17]. When the piezoelectric layers are in the short-circuit condition, a conventional multi-frequency EMEH (MEMEH) with a magnetic oscillator can be developed. The magnetic oscillator and induction coil are the component units of the 1 DOF linear EMEH (LEMEH). The combination of the LPEH and LEMEH is named LVEH. Its output power frequency response is compared with that of the HEH.  
Figure 8: Prototype of the HEH and the experimental system.
## 2 Related Research
### Intelligent Transportation System
#### 2.1.1 Traffic Forecasting Information Based on Big Data  
The Ministry of Land, Infrastructure, Transport, and Tourism of Korea and the Korea Road Corporation have constructed and are operating a traffic management system for national roads to provide traffic information on national expressways and general national highways. Road traffic and special situation information are provided to drivers in real time through road signs, the Internet, smartphones, Twitter, and automatic response systems. The traffic information center provided by the Seoul Regional Land Management Agency, Korea Expressway Corporation, the National Police Agency, and local governments distributes traffic information through various media, such as homepages, Internet portals, smartphones, navigation systems, Twitter, and ARS (automatic response system). Road traffic information is provided and utilized through various media and technologies, such as carriers and broadcasters providing main road traffic information via smartphones, DMB (digital multimedia broadcasting), navigation systems, etc.  
In Germany, as the population density of the area around the autobahn increases, online traffic simulation (OLSIM), supported by the German government, was developed to solve traffic congestion problems on the autobahn caused by the increase in traffic volume. It collects data from about 4000 loop detectors and provides users with real-time traffic conditions and 30 min hourly traffic condition forecast information via the Web. Figure 1 shows the traffic situation forecast information system in Germany.  
Big data traffic forecasting technology collects, stores, and analyzes a wide variety of information and provides it as a variety of application services, including intelligent home networks, universal healthcare, smart environment management, and mobile sensor-based personalization. Information provision in various fields, such as services and ubiquitous sensor network (USN) virtual world applications, can be applied to the service system industry and markets and can promote their development. In addition, it is a technology that matches the trends in power generation technology, such as driverless self-driving vehicles and smart roads. It can be applied technically on the roads, and the safety of drivers is improved by providing predicted driving information, which is effective in reducing traffic accidents.