esa-sceva/satcom-chunk-collection huggingface dataset:
## 2 Related Work
### A Critical Question in the Development of Wireless Sensor Networks  
A wireless sensor network is a type of distribution system and is composed of a large number of specially designed sensors [5, 6, 7]. Battery power is the main power supply for sensors in a WSN. The power consumption and workload of each sensor are not balanced. Additionally, the transmission range and work power of each node are strictly limited. The task of a wireless sensor network is control and monitoring in the deployment area under adverse circumstances for a long period of time. The node is rarely maintained, replaced or charged because of deployment conditions. The performance of the network will be affected when the power of node is exhausted. Therefore, the question of how to prolong network lifetime and maintain network Quality-of-Service (QoS) is important. In fact, QoS is a technique of network resource management to provide the stable and predictable transmission quality for user requirements. QoS of network as a guarantee of service quality in a network is easily influenced by link quality. An oversupply of links causes significant channel interference, whereas fewer links lead to fail in discovering the links to compose a reachable route to the destination. Thus, how to find a certain set of links is a significant step to establish a QoS-enabled WSN. Recently, the researches on QoS [8, 9] had been proposed to construct an optimal WSN through topology control [10] and a routing algorithm [11, 12]. The traditional evaluation indices of QoS are defined by latency, jitter, loss and throughput of packets in transmission. However, as the evolution of wireless sensor networks, the reachability and energy efficiency of nodes have become ones of important issues in QoS [13, 14, 15, 16, 17, 18]. The problem of network lifetime arises because a WSN will not operate properly if the network has too many disabled sensors. This problem implies that the lifetime of a network is related to the energy efficiency of the nodes in networks. In this paper, we will explore the relationship between node reachability and network topology. That will be critical to the QoS of WSNs.
## 3 Experimental Section
### Measuring Setup  
The main components involved in the basic measurement setup are described in Figure 9. For frequency measurements, a network analyzer (E5062A from Agilent Technologies) and a frequency counter (5385A from HP) were used. Sensor signals were recorded using self made oscillator circuit provided with a switch of relays to convert different array electrodes to the oscillator circuit. The chemical sensor array chamber is connected to air and analyte inlets in which, flow of air through various analyte reservoirs was controlled via mass flow controllers (Tylan-RO7020) in order to allow calculated amounts so as to generate required concentrations. Whole equipment, excluding electronic parts, was thermostated by circulation of water at specific temperature as required. Although, a source of dried and compressed air was used throughout the experiments, yet it is impossible to fully get rid of inherent humidity which was 0.5-2%RH, when measured by hygroscope (Rotronic DV-2).
# An Overview of Position Sensorless Techniques for Switched Reluctance Machine Systems
## 3 An Overview of Recent Development in Position Estimation Methods of SRM
### Magnetic-Model-Based Position Sensorless Methods
#### 3.1.1 Based on Flux-Current-Position Methods  
There is a mapping relationship between the rotor position and the flux-linkage-current, which determines that this is a direct and effective rotor position direction. This kind of method consists in using various features to generate new flux-linkage-based methods, on the one hand building more accurate models, and on the other hand using fewer prior parameters to reduce pre-storage.  
During the operation, the calculation of the flux linkage satisfies the following Formula (5).  
\[\psi_{k}(t)=\psi_{k}(0)+\int_{0}^{t}{(U_{k}-R_{k}i_{k})dt} \tag{5}\]  
where \(\psi_{k}(0)\) represents the flux linkage value at the initial moment.  
Methods based on 3D LUT [63; 64; 65] and flux linkage modeling [66; 67; 68; 69; 70; 71; 72; 73] are used to obtain the position signal by obtaining current and flux linkage information. Then, to gradually reduce the dependence on the pre-storage, the magnetic characteristics, such as the flux linkage and inductance increment of the SRM, are decomposed into the rotor position and the appropriate amount of phase current, and a one-to-one correspondence between the flux linkage and the rotor position can be established. The position estimation is carried out within the wide speed range. However, the dependence on speed and torque control strategy is extremely strong [74; 75]. Using only a one-phase current sensor and virtual voltage to build a flux linkage model to estimate the rotor position can perform rotor position estimation in a wide speed range [76]. However, the stability of the method is worth exploring due to the severe nonlinearity of the flux linkage On the other hand, to compensate for the limitation brought by model accuracy, based on numerical method [77; 78], quadrature flux estimators [79], Kriging interpolation model [125], and compensation error method are used. Recently, the accuracy of the method has been further improved by eliminating the errors of the flux linkage modeling by compensating errors online and estimating the winding resistances [80; 81]. The accuracy of position estimation is enhanced by the special flux linkage curve of position [82; 83; 84]. These methods indirectly contribute to the accuracy of rotor position estimation.
## 2 Operating Principle of the Proposed Circuit
### Inverting Voltage Buck Operation  
This operation reverses the polarity of the output voltage with respect to the input voltage. The explanation of this behavior can be easily understood with its operation in modes III and IV. In the operation of mode III, where the output is negative for positive input voltage, the requirement of the operation is performed with the conduction of transistors \(Q_{3}\) and \(Q_{4}\) by establishing a current conduction path in which power is being stored in the inductor and also consumed by the load, as can be seen from the underlined path of Figure 5a. In this operation, as the output is an inverted form of the input, the inductor voltage is the sum of the input and output voltage, as can be analyzed from the loop analysis of Figure 5a.  
\[v_{L}(t)=v_{s}(t)+v_{o}(t) \tag{5}\]  
In the second interval of operating mode III, the conduction of transistor \(Q_{4}\) and diode \(D_{6}\) facilitates the recovery of the stored energy of the inductor, as depicted in Figure 5b.  
Figure 5: Equivalent power transfer circuits for inverting voltage buck operation: (**a**,**b**) for mode III; (**c**,**d**) for mode IV.  
There is no change in the value of the inductor voltage, as seen in the operation of modes I and II.  
\[v_{L}(t)=-v_{o}(t) \tag{6}\]  
The inverting requirement of output voltage for the negative input voltage is achieved by shifting the switching behavior of the transistors \(Q_{3}\) and \(Q_{4}\) to \(Q_{1}\) and \(Q_{2}\), respectively. The power transferring loops of Figure 5c,d illustrate how the input power is stored in the inductor PWM on interval and is released to load during the PWM off interval.  
Equations (5) and (6) also hold their states for the inverting operation of the input voltage. Equation (3) can be modified to determine the voltage transfer ratio for voltage inverting buck operation.  
\[\frac{1}{T}\int\limits_{0}^{T}v_{L}(t)dt=\frac{1}{T}\int\limits_{0}^{kT}[v_{s }(t)+v_{o}(t)]dt-\frac{1}{T}\int\limits_{0}^{(1-k)T}v_{o}(t)dt \tag{7}\]  
\[\frac{V_{o}}{V_{s}}=-k=-k_{v} \tag{8}\]  
The negative signs with Equations (7) and (8) ensure that the output voltage always exists in the inverted form of the input voltage. This section comprehensively explains the circuit operation employed to regulate the output voltage from some minimum level (ideally zero volts) to the value of the input voltage in non-inverting and inverting forms. The control of the duty cycle helps regulate the output voltage.
## 5 Conclusions  
The impact of climatic factors and human activities on the dynamics of forest NPP and NDVI from 1982 to 2013 were examined. The main conclusions drawn from our paper are summarized as follows:  
1. This study examined the general agreement between temporal trends in forest NDVI and the NPP in the Yangtze River basin. The mean annual forest NPP and NDVI in the Yangtze River basin from 1982 to 2013 exhibited generally decreasing trends from the southeast to northwest. The southeastern part of the Yangtze River basin has satisfactory hydrothermal conditions, which could meet the needs of vegetation growth and high yield. The northwest region has low productivity due to poor water and heat conditions.
2. By performing a comparative analysis of temperature and precipitation for the past 30 years, we concluded that the forest NPP and NDVI in the Yangtze River basin were sensitive to climate changes. Positive correlations can be found between the forest NPP (NDVI) and temperature in most of the study area. The forest NPP and NDVI with the annual precipitation revealed the positive correlations in around 58% of the study area. Moreover, large-scale drought event in the years 2004-2005 has led the NPP to obviously decrease in the middle and lower Yangtze River basin.
3. Major ecological projects have played a positive role in improving forest coverage and forest protection. The increase in forest areas from the year of 2000 to 2010 was larger than that from 1990 to 2000. The forest areas in the Yangtze River basin increased by 1409 km\({}^{2}\) from 2000 to 2010. Although the forest NPP increased during the past 30 years, the increasing rate for the NDVI was higher than that of NPP, especially after the year 2000.  
Human activity and climate change have had complex and interactive effects on terrestrial NPP and NDVI. The manifestations of these two forces have typically been lumped together. Therefore, the joint impacts of climate change and human activities on vegetation should be the subject of future research.  
[PERSON] provided the datasets including the required supporting software needed for the analyses; [PERSON], [PERSON], [PERSON] and C.[PERSON]Y.X. cooperated in designing and improving the concept of the research project and related processes; [PERSON], [PERSON], [PERSON] and [PERSON] conducted the data processing and analysis. All the authors participated actively in preparing and reviewing the manuscript.  
This paper is financially supported by National Natural Science Foundation of China (Grant No. 91747203 and 41171020) and Distinguished Young Scholars Fund of Nanjing Forestry University (NLJQ2015-01). The project supported by the Six Talent Peaks project in Jiangsu Province (Grant no. 2015-Y-017) and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).  
We would like to thank the National Climate Centre in Beijing for providing valuable climate datasets. We want to thank the editor and reviewers for their valuable advices and suggestions that helped us improve this manuscript.  
The authors declare no conflict of interest.
# Hybrid Methodology Using Sentinel-1/Sentinel-2 for Soil Moisture Estimation
## 2 Materials and Methods
### Database
#### 2.1.3 Sentinel-2  
After the launch of Sentinel-2 A and B on 23 June 2015 and 7 March 2017, respectively, optical data became free and open access with a spatial resolution varying between \(10\) m \(\times\) 10 m and 60 m \(\times\) 60 m and a revisit time of up to 5 days in 13 spectral bands at visible and mid-infrared wavelengths. In the present study, we used Sentinel-2 surface reflectance products downloaded from the Theia site ([[https://www.theia-land.fr/](https://www.theia-land.fr/)]([https://www.theia-land.fr/](https://www.theia-land.fr/)), accessed on 16 May 2022), already orthorectified and atmospherically corrected with a mask of clouds and shadows owing to the MAJA algorithm [75]. On each acquisition date and using red visible and near infrared bands with center wavelengths of approximately 665 and 833 nm, respectively, we calculated the Normalized Difference Vegetation Index \((NDVI)\) and averaged this index for each studied station as expressed in the following equation:  
\[NDVI=\frac{R_{NIR}-R_{Red}}{R_{NIR}+R_{Red}} \tag{1}\]  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Network** & **Country** & **Number of Selected Stations** & **SM Sensors** & **References** \\ \hline MAQU & China & 1 & ECH20-EC-TM & [PERSON] et al. [57]; & \\  & & & [PERSON] et al. [58] & \\ \hline MOL-RAO & Germany & 1 & TRIME-EZ & [PERSON] and & \\  & & & [PERSON]. [59] & \\ \hline NAQU & China & 5 & 5 TM & [PERSON] et al. 2011 [60] \\ \hline REMEDHUS & Spain & 13 & Stevens-Hydra-Probe & Gonzalez-Zamora & \\  & & & & & \\  
where \(R_{NIR}\) and \(R_{Rad}\) are the surface reflectance in the two bands, near infrared and red visible, respectively.
# Fuzzy Multi-Criteria Based Trust Management in Heterogeneous Federated Future Internet Testbeds
## 1 Introduction
Fuzzy logic and systems are widely used in research problems of computer networks, e.g., [6; 7], and conveniently express the human opinion on vague concepts. Furthermore, the proposed framework evaluates the credibility of the experimenters, using Service Level Agreement (SLA) data, in order to mitigate the effect of abnormal or malicious evaluations and guarantees that the reputation score is fairly computed. The operation of the proposed framework over an existing real federation of testbeds environment is demonstrated, and its performance using monitoring data and user ratings from actual federated testbeds is evaluated. Finally, the operational superiority of the proposed system against an existing reputation-based trust framework, i.e., FTUE [8] that processes exclusively numerical values, is highlighted and discussed. The rest of the paper is structured as follows: Section 2 discusses related work. Section 3 presents the details of the introduced reputation system and credibility mechanism. Section 4 contains indicative numerical results about the operation and performance of the introduced trust framework over real federated testbeds, while comparative results against the FTUE framework are presented. Our conclusions and future work are drawn in Section 5.
## 4 Performance Evaluation in Edge Scenarios
### I/O-Intensive Workload
#### 4.3.1 Sequential Read/Write Performance  
Sequential read and write operations are both performed on files stored on disk, meaning relevant file information is not preloaded in memory. In the case of sequential write operations, new files are written, requiring not only data storage but also the overhead of tracking the data's location on the storage medium, known as metadata. The results are shown in Figure 3. Occlum's sequential read and write performance is significantly weaker than Gramine's, which is a result of the performance overhead introduced by the fully encrypted file system. When the buffer size was small, Gramine's sequential read and write speed could match or even surpass that of native Linux. However, once the size exceeded 1 MB, there was a noticeable decline in performance as the block size increased.  
The reason for this is that Gramine reached its preset maximum read/write buffer size, and further increased its result in multiple read/write operations, which reduced efficiency. When the buffer size for sequential read reached 16 MB, Gramine's efficiency dropped to only about 20% of that of the native Linux, as shown in Figure 3a.
# Discrete Semantics-Guided Asymmetric Hashing for Large-Scale Multimedia Retrieval
## 4 Experiments
### Further Study
#### 4.5.6 Effects of Parameters  
In this section, we conduct parameter sensitivity analysis experiments to observe the variation of mAP scores under different \(\alpha\) and \(\gamma\). In this experiment, by prefixing the code length as 64 bits, we vary the parameters \(\alpha\) and \(\gamma\) in the range of \(\{10^{-5},10^{-4},...,10^{4},10^{5}\}\). Figures 3 and 4 report the results. From these results, we observe that the performance of our proposed DSAH is relatively stable on a wide range of \(\alpha\) and \(\gamma\) values. Specifically, on the MIRFlickr dataset, when \(\alpha<10^{0}\) and \(\gamma<10^{1}\), the retrieval performance becomes stable. On the NUS-WIDE dataset, when \(\alpha<10^{2}\) and \(\gamma<10^{1}\), the scores of mAP have a very small fluctuation. Therefore, our proposed method can be easily tuned for practical implementations.
# Integrated Evaluation of Reliability and Power Consumption of Wireless Sensor Networks
## 6 Experimental Evaluation
### Sensitivity Analysis
#### 6.3.2 Results
Besides that, as the region is located on the edge of the WSN (as mentioned in the Section 6.3.1) and the sink node in the centre of WSN, we also expected that the _Place Size_ (PIS) is one of the factors that affected the WSN reliability. The _Node Number_ (NN) did not affect so much the WSN reliability because the region had only one node independent from the number of sensor nodes of the WSN. To understand the other factors, it is necessary to remember that the battery level was considered in the reliability of the sensor node. Thus, the factors that affected the WSN power consumption also affect the WSN reliability. Note that, from _Packet Size_ (PaS), the order of impact was maintained. The only exception was _Placement Algorithm_ (PA): it does not affect the WSN reliability as well as the WSN power consumption because the region was always in the same position regardless of the routing algorithm used. However, it is noteworthy that the interaction between _Placement Algorithm_ (PA) and _Routing Protocol_ (RP) had a median impact (11 th position) in WSN reliability, because (most likely) _Routing Protocol_ (RP) had a higher impact on the WSN reliability.
# The Reproduction and Evaluation of Star Fields with the Milky Way in a Planetarium
## 2 Experiment
### Reproduction Apparatus  
There are two types of projection systems that produce images in a planetarium: optical and digital. Owing to the resolution and color tone limitations of digital projectors, it is difficult to reproduce a detailed Milky Way with sufficient resolution to evaluate image faithfulness. Therefore, in our experiment, a planetarium with an optical system using star plates was used to reproduce fixed stars, nebulas, and the Milky Way, as shown in Figure 1. Stars were projected on the dome screen by passing light through the star plates installed in the projector. The direct luminance of the stars was adjusted by inserting transmission filters in front of the light sources. The representation size and star density were controlled by the diameter of the hole and the number of stars in the star plates, respectively. Therefore, we defined the three parameters (transmittance, representation size and star density) of individual stars.
# Constitutive Analysis of the Anisotropic Flow Behavior of Commercially Pure Titanium
## 1 Introduction  
Titanium and its alloys are used in many commercial applications in the aerospace, biomedical, sporting goods, and sea water plant industries [1; 2; 3]. Such a wide application is attributed to the high specific strength, biocompatibility, and high corrosive resistance of these alloys. Among various alloy variants, commercially pure titanium (CP-Ti) has been used in the applications of heat exchangers or pressure vessels due to its remarkable corrosive resistance and cold formability. It also has an economical benefit from excluding expensive alloying elements such as Nb, Ta, and Hf [4].  
Besides its engineering advantages, CP-Ti possesses a significant anisotropy of mechanical behaviors due to the intrinsic nature of its hexagonal close-packed structure [5]. In other words, the plastic deformation behavior of CP-Ti considerably varies depending on the direction of the applied loading. A conventional rolling process gives rise to a strong split basal texture in CP-Ti, where (i) [0002] basal planes are aligned with the rolling direction (RD) and (ii) the basal axis is tilted from the normal direction (ND) to the transverse direction (TD) in the cross-section [6]. Such a preferential texture development resulted in plastic anisotropy, as mentioned above.  
An effective way to interpret the mechanical and/or microstructural behaviors of CP-Ti, including plastic anisotropy, is a constitutive analysis. Such an approach establishes a constitutive equation correlating various physical quantities, providing an estimation of the specific properties under a given condition. For example, [PERSON] et al. [7] made a highly accurate prediction for the transient stress drop of electropulsing-treated CP-Ti utilizing the modified Johnson-Cook model integrated with the term of dynamic strain aging. [PERSON] et al. [8] employed a representative volume element simulation to model a void formation at the phase interface of titanium alloys. [PERSON] et al. [9; 10] modified a full-variation porous plasticity model to interpret the void coalescence of ductile metals.  
This study aims to clarify the role of anisotropy in microstructural evolution and the compressive deformation properties of rolled CP-Ti sheets. The plastic deformation behaviors were investigated depending on the loading direction of RD, ND, and TD. In addition, our research novelty is the introduction of a constitutive approach to divide flow stress into three stress components representing a dynamic grain refinement, dislocation pile-up, and texture hardening. Such an approach assists in measuring the contribution of each stress component to the total plastic deformation behavior depending on the loading direction. Furthermore, this approach requires a significantly lower number of parameters as compared with the microstructure-based numerical models in the literature [8; 9; 10].
## 3 Types of Supplementary Dampers and Their Characteristics
### Tuned Mass Dampers
#### 3.5.5 Design Considerations  
When designing tuned mass dampers, several factors must be taken into account to ensure optimal performance. The accurate determination of structural dynamic properties is crucial for proper tuning of the TMD. The selection of an appropriate mass ratio, typically 1-5% of the modal mass, is essential for balancing effectiveness and practicality. Designers must also consider spatial constraints for TMD installation, as these systems often require significant space. Provision for TMD maintenance and potential re-tuning should be incorporated into the design to ensure long-term effectiveness.