esa-sceva/satcom-chunk-collection huggingface dataset:
# Research on Application of Improved Quantum Optimization Algorithm in Path Planning
## 4 Analysis of Evacuation Path Planning Model Experiment
### Experimental Analysis of Multi-Robots Path Planning  
In order to verify the effectiveness of the QABC, the model is solved by simulation. The simulations of QABC, ACA and ABC were conducted for comparison tests, respectively. The parameters were set as follows: population size \(N=200\), limiting frequency _limit_ = 50, maximum cycle number _maxcycle_ = 1000, number of quantum bits \(n=2\) and 19 evacuation nodes.
## 1 Introduction  
Lasers emitting in the 2 \(\upmu\)m spectral region have increasingly gained attention from scientific researchers for plentiful applications in medical detection, atmospheric sensing, molecular spectroscopy, optical pumping of longer wavelength solid-state lasers, etc. [1; 2; 3; 4]. Holmium (Ho) is the main doping material in the gain medium that produces lasers working in the 2 \(\upmu\)m wavelength range. According to related reports, one of the methods to achieve high-efficiency Ho\({}^{3+}\) laser emission is co-doping with Tm\({}^{3+}\), and the other one is the direct resonant pumping of singly Ho-doped lasers [5; 6; 7; 8; 9; 10]. The 2 \(\upmu\)m laser radiation obtained through the latter approach has high conversion efficiency, is operable at room temperature, and has minimal thermal loading. In recent years, the search for new subject materials for efficient Ho\({}^{3+}\) laser operation is focusing on gadolinium vanadate (GdVO4) crystal. The tetragonal uniaxial GdVO4 crystal was previously proved to be an extremely practical laser material for Tm\({}^{3+}\) ions [11]. GdVO4, as a host material for thulium and holmium, has a significant feature for diode-pump lasers [12]. First of all, it has a giant thermal conductivity, which is conducive to the rapid cooling of the crystal during application. What's more, its thermal conductivity is at least twice higher than that of YVO4, and even higher than that of YAG crystals, a widely known material with high thermal conductivity. A lot of studies have reported on diode-pumped Tm: GdVO4 lasers [13; 14; 15]. Additionally, both continuous-wave (CW) and Q-switched Ho: GdVO4 lasers pumped by Tm-fiber were also reported [16]. However, we have yet to find a report on diode-pumped Ho: GdVO4 laser.  
In this contribution, for the first time, we measured the laser characteristics of Ho: GdVO4 crystal and reported a diode-pumped Ho: GdVO4 laser. A considerable output power 1.8 W was obtained in the laser, with a slope efficiency of 39.5%. The center wavelength was located at 2047.9 nm, and, moreover, the lasing wavelength red-shifted to 2048.2 nm at lower output transmittance. In addition, we obtained the beam quality factor M2 of the laser in the x- and y-direction to be approximately 1.4 and 1.3, respectively.
# Spatial and Temporal Variation of GPP and Its Response to Urban Environmental Changes in Beijing
## 3 Results  
### Spatiotemporal Distribution and Variation of AGPP in Beijing  
This study used AGPP data from SCIDB to analyze the spatiotemporal distribution and variation of AGPP in Beijing. This AGPP data contains some no-data areas and some invalid data areas that are less than zero. The result is shown in Figure 1. The geographic distribution of AGPP across Beijing reveals a discernible trend, marked by higher values in the northwestern areas and lower values in the southeastern areas. From 2000 to 2020, AGPP in Beijing ranges from below 0 to 3000 g C\(\cdot\)m\({}^{-2}\cdot\)a\({}^{-1}\), and the multi-year annual mean GPP varies from \(-116.18\) to 2527.71 g C\(\cdot\)m\({}^{-2}\cdot\)a\({}^{-1}\) (Figure 1). The mean AGPP in mountainous areas was significantly larger than the mean AGPP in the plains. In the northwestern mountainous areas, such as the Jundu Mountains, AGPP generally exceeded 1000 g C\(\cdot\)m\({}^{-2}\cdot\)a\({}^{-1}\), while in the plain areas in the southeast, AGPP was generally lower, mostly below 1000 g C\(\cdot\)m\({}^{-2}\cdot\)a\({}^{-1}\).  
Figure 2 shows spatial and temporal variation trends of AGPP, AGPP increased in most regions in Beijing, with a growth rate ranging from \(-\)55.35 and 71.98 g C\(\cdot\)m\({}^{-2}\cdot\)a\({}^{-1}\) (Figure 2a,b). Significantly decreasing areas are mainly concentrated within Beijing's sixth ring road (Figure 2b). Figure 2c shows the 21-year time series of annual mean GPP. Figure 2c presents the 21-year time series of annual mean GPP, showing an overall increase from 2000 to 2020 at a rate of 17.41 g C\(\cdot\)m\({}^{-2}\cdot\)a\({}^{-1}\). The apex of AGPP values was registered in the year 2019. Conversely, the nadir was noted in 2003.  
Figure 1: Spatiotemporal variation of AGPP in Beijing from 2000 to 2020.  
In the M-K curve of the AGPP mutation test in Figure 2d, the UF curve is greater than 0 except for the case of less than 0 in 2000-2004, indicating that the average annual Gross Primary Productivity has shown a steady upward trend since 2004, and the upward trend has been significant since 2011. The UF and UB curves had only one crossing point in 2013, and this crossing point was outside the critical line with a critical value of 1.96, so it was hard to judge that 2013 was the time when the mutation began.
###### Abstract  
In this paper, the performance of a Roots pump for hydrogen recirculation in proton exchange membrane (PEM) fuel cell system is simulated based on CFD modeling. The Roots pump is in a three-lobe configuration with helical rotors, and it is developed specifically for fuel cell systems between 60 to 110 kW. A three-dimensional model of the Roots pump is established to predict the pump performance, including the flow rate and power consumption under various operating conditions. Extensive simulations were conducted and then verified experimentally by operating with working fluids of air and helium. Based on the validated CFD model, the contents of water vapor and nitrogen in the hydrogen recirculated are taken into account to evaluate the Roots pump performance numerically according to the actual conditions of the recirculating hydrogen at the stack outlet. It is shown that the volumetric efficiency and isentropic efficiency are improved with the increase fraction of water vapor and nitrogen. It is found that the performance of the Roots pump integrated in the PEM fuel cell system is between the performance of the pump working with air and helium. Finally, correlations of volumetric efficiency and isentropic efficiency are given based on the CFD results to show the general pattern of this kind of hydrogen pump. It is believed that these equations are very helpful to the design and operation control of the PEM fuel cell system.  
Roots pump; performance; hydrogen recirculation; PEM fuel cell; CFD 2020; 10 November 2020; Published: 13 November 2020
# Hybrid Chaotic-Based PRNG for Secure Cryptography Applications
## 2 Known 1D Chaotic Maps
### Tent Map  
The tent map is a simple, discrete-time dynamical system that is often used to model chaos-based applications. It is defined by the piecewise Equation (2):  
\[x_{n+1}=\begin{cases}ax_{n}&\text{if }x_{n}<0.5\\ a(1-x_{n})&\text{if }x_{n}\geq 0.5\end{cases} \tag{2}\]  
Figure 1: (**a**) Phase space of the logistic map. (**b**) Phase space of the tent map. (**c**) Phase space of the sine map. (**d**) Bifurcation diagrams of the logistic map. (**e**) Bifurcation diagram of the tent map. (**f**) Bifurcation diagram of the sine map.  
where \(x\) is the state variable, \(n\) is the time step, and \(a\) is the parameter. The range of the parameter \(a\) for \(1<a<4\) between 0 and 2 determines the upper and lower limits of chaos in the system. For \(a\leq 1\), the map is stable and periodic, while for \(1\leq a\leq 2\), the map exhibits chaotic behavior.  
The tent map is known for the tent-like shape of its phase space, and it is one of the simplest examples of a chaotic system. It is often used as a prototypical example in the study of chaotic and nonlinear dynamics.
## 3 Experimental Results
### Battery Tests  
Extensive tests were performed to the individual battery cells and the battery pack in order to ensure its performance during a typical flight.
# Remote Sensing of Environmental Changes in Cold Regions: Methods, Achievements and Challenges
## 2 Principles and Methods
### Remote Sensing of Snow  
Snow and glaciers provide one-sixth of the world's population with fresh drinking water, and seasonal snow is the main fresh-water source at mid-latitudes [98]. Snow is also a crucial factor controlling the seasonal radiation balance of the land surface, and a sensitive indicator of global climate change. Snow measurement is essential to snowmelt driven runoff predictions, water resources management, flood control, and climate change studies [99]. Key snow properties derived from remote sensing include snow cover area or extent, structure (e.g., depth, density), and water equivalent.
# Computation of Psycho-Acoustic Annoyance Using Deep Neural Networks
## 4 Evaluation and Results
### Direct Calculation vs. CNN Prediction in Terms of Computation Time  
This section discusses the differences in computation time required by PA direct calculation and CNN PA prediction. To this end, we measured the time taken by the algorithm to calculate the psycho-acoustic parameters and psycho-acoustic annoyance PA, and the time taken by the neural network to predict the PA value, using the computers described in Section 2.2 in both cases. The results are shown in Figure 5.  
The time used by CNN to predict the PA value (blue) from raw audio signals is significantly smaller than the one obtained by direct calculation (red). The average time for CNN prediction is 0.004 s while for direct calculation is 1.217 s. Thus, a speedup higher than 300 is achieved by the proposed CNN-based system. It can also be observed that the times obtained from the CNN are almost constant while the times obtained by direct calculation depend on the complexity of the input sound. All these results confirm that the proposed CNN model is a good candidate for IoT-based  
Figure 4: PA Calculated vs. PA Predicted by CNN. Predicted PA values with Error > 10% marked.  
Figure 5: Elapsed time in direct calculation and elapsed time in prediction.  
implementations, where the PA analysis can be comfortably performed in real time with a computation time much smaller than 1 s.
## 3 Results
### Temporal and Spatial Resolution  
LCA examines the environmental impact integrated over time and space [71]. In some cases, however, a high temporal or spatial resolution is needed to identify specific improvement potentials. Dynamic analyses can be performed by extending MFA, SFA, and LCA (including LCI) towards dynamic MFA [72,73], dynamic SFA [74], and dynamic LCA [75], respectively. The framework of the Pho method is explicitly intended for dynamic analysis [58] (p. 13). Other methods can also be extended, although the additional understanding might be minor in some cases compared to the increased complexity. Dynamic analyses are essential for interpreting the correlation of varying ambient conditions, especially temperature and humidity.  
The spatial resolution depends on whether the inventory is top-down, often leading to a spatial black box. Methods that are mainly intended for analyzing economies and regions are performed from the top down, such as MFA. _Emergy_ analysis is also performed from the top down [13] (pp. 219-220).  
Methods for technical processes such as exergy analysis, the PhO method, and process-based LCI are conducted from the bottom up. SFA, ENA, LCA [13] (p. 220), and most footprints [12] pursue a bottom-up approach. Thus, a process-based bottom-up approach is preferable for analyzing cooling systems.
# Detection and Mitigation of RPL Rank and Version Number Attacks in the Internet of Things: SRPL-RP
## 1 Introduction
### RPL Security  
Secure routing protocols for data packets in IoT networks is a challenging issue due to the characteristics that are inherited from other networks [6]. Data packet routing in IoT-constrained devices suffer from potential security threats, and this has a considerable impact since it is related to the users [7]. Several RPL attacks occur through the activities of malicious nodes during the data packet routing among devices [8]. The RPL security has been extensively reviewed in [9; 10; 11]. Various kinds of RPL attacks have been analyzed, yet most of the studies have not concentrated on the mechanisms of secure RPL. In recent years, efforts have been made to design secure routing protocols for IoT-constrained devices. However, they all rely on conventional cryptographic functions, which drastically drain the resources of devices and impact the performance of the constrained devices likely to be used in IoT applications. The RPL characteristics, such as a lack of infrastructure, unreliable links, resource constraints, limited physical security, and dynamic topology, make them vulnerable and hard to protect against attacks. The data traffic density in certain nodes can lead to depleting batteries and resources faster than other nodes, which deactivates the routing data to the root node. Due to the billions of interconnected devices on the network, securing and protecting them from different forms of attacks creates a critical challenge. When these devices are vulnerable to attacks, such as rank attacks and version number attacks, users will feel that their data are insecure [7; 8].
# A New Monocular Pose Estimation Method for the Coplanar P4P Problem
## 4 Conclusions and Discussion  
A new method to estimate a parallelogram object's pose and shape parameters from its single image is presented. If there is no scale information, a scale factor will exist between the estimation results and the real values of the object's position and the vertices' coordinates. The four points need not to be a rectangle's four vertices and their coordinates need not to be known. In fact, it is also a method to calibrate a camera's extrinsic parameters by a parallelogram reference object.  
At the same time, the new method expands the conclusions of the P4P problem by obtaining a new conclusion regarding the coplanar P4P problem when the four points are a parallelogram's four vertices. In other words, If the four points are a parallelogram's four vertices and the distance between two of them is known, a unique solution will exist for the P4P problem, and if no scale information is known, a scale factor will exist between the real position and the estimation result.  
The new method is verified by real data experiments. In the experiments, the pose and shape parameters results estimated by the new method accord well with that estimated by a traditional bundle adjustment method which takes all of the vertices as known. For most general applications, the results of the new estimation method will be practicable.  
As previously mentioned, many parallelogram objects exist in real scenes, including some buildings and parallelogram patterns on buildings, etc. Especially, by considering two images in a monocular image sequence of a placidly walking human or other placidly moving objects, a parallelogram object can be obtained, as shown in Figure 6. The human's medial axes in the two images are used as a pair of opposite sides of a parallelogram. The human's stature can be used as the known side distance. Then, the position and attitude parameters of the placidly walking human can be estimated by our new method.  
Figure 6: Parallelogram objects obtained from an image sequence of a placidly walking human.  
**Author Contributions:** Conceptualization, X.Y. and Y.S.; methodology, Y.S.; software, X.Y.; validation, X.Y.; formal analysis, X.Y.; investigation, X.Y.; resources, X.Y.; data curation, Y.S.; writing--original draft preparation, X.Y.; writing--review and editing, X.Y.; visualization, X.Y.; supervision, Y.S.; project administration, Y.S.; funding acquisition, X.Y. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was funded by the National Natural Science Foundation of China, grant number 62173335.  
**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.  
**Data Availability Statement:** Data sharing not applicable to this article as no datasets were generated during the current study.  
**Conflicts of Interest:** The authors declare no conflict of interest.
## 3 Results and Discussion
### Isothermal Analysis
#### 3.3.7 Error Function Examination for the Best and Most Appropriate Isotherm Model  
The best-fit model for the investigational data was calculated by numerous error functions, such as the average percentage error (APE) equation, chi-square error (\(\chi^{2}\)) equation, and the sum of absolute errors (EABS). The data obtained from the different error functions are summarized in Table 3. From the observed data, the best appropriate isotherm models are [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], and Harkins-Jura. Nevertheless, the error functions test provided variable data for all models, and the evaluation among the models focused on all error functions individually. For the EABS and \(\chi^{2}\) equation, all the isotherm models can be applied to the investigational data, except the Harkins-Jura isotherm.  
Figure 16: Linear Smith isotherm of the removal of IV2R.  
Figure 15: Linear Harkins–Jura isotherm of the removal of IV2R.
## 5 Case Studies Analysis
### Multi Scenario Sample Data Generation
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{\(\Gamma_{\text{wt}}\)} & \multirow{2}{*}{\(\Gamma_{\text{pv}}\)} & **Initial** & **Equipment** & **Environmental** & **Total Cost of** & **Time** \\  & & **Investment** & **Maintenance** & **Goverance** & **Microgrid/** & **/ms** \\  & & **Cost/JPY** & **Cost/JPY** & **Costs/JPY** & **JPY** & **JPY** \\ \hline \multirow{4}{*}{0.08} & 0.03 & 176,890.56 & 23,793.14 & 5477.04 & 206,160.73 & 8.06 \\  & 0.04 & 176,765.47 & 23,951.85 & 5481.02 & 206,198.34 & 7.84 \\ \cline{1-1}  & 0.05 & 176,640.39 & 24,110.56 & 5485.00 & 206,235.95 & 7.51 \\ \cline{1-1}  & 0.06 & 176,533.32 & 24,261.97 & 5489.11 & 206,234.59 & 7.26 \\ \cline{1-1}  & 0.07 & 176,426.25 & 24,413.38 & 5493.23 & 206,233.23 & 7.09 \\ \cline{1-1}  & 0.08 & 176,319.18 & 24,564.79 & 5497.34 & 206,231.87 & 6.81 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: _Cont._  
Figure 3: Optimization and dispatch results of microgrid (\(\Gamma_{\text{wt}}=\Gamma_{\text{pv}}=0.05\)). In summary, when the fluctuations in wind turbine and photovoltaic power plant outputs increase, the system chooses to maintain power balance by increasing the output of micro combustion units at noon, and the impact and mode of the two are similar. But at night, the fluctuations in wind turbines have a significant impact on the scheduling and operation of microgrids, especially in terms of the amount of electricity purchased by microgrids. This is because the uncertainty of the wind still exists at night, and the factors such as the ambient temperature at night will also affect the performance of the wind turbine, making its output power not as stable as during the day. The photovoltaic power station mainly relies on solar radiation for power generation, and its output power fluctuates with the change in solar radiation intensity, angle, and other factors during the day. At midday, when the solar radiation is relatively stable, the power fluctuations are relatively small. At night, without solar radiation, the output of the photovoltaic power station is zero, which will not affect the system because of the continuous fluctuations in natural energy, like wind turbines. Figure 4: Optimization and dispatch results of microgrid (\(\Gamma_{\rm wt}=0.05\Gamma_{\rm pv}=0.08\)). Figure 5: Optimization scheduling results of microgrid (\(\Gamma_{\rm wt}=0.08\Gamma_{\rm pv}=0.05\)). In terms of the microgrid dispatching strategy, there is no power input from the photovoltaic power station at night as a buffer. Once the wind turbine fluctuates, the power balance of the whole microgrid will be greatly affected. Because, at this time, it can only rely on another limited power supply to adjust, such as energy storage system and micro combustion units, the energy storage system may have problems such as capacity limits, so the impact of the fluctuation of wind turbines on the dispatching operation of the microgrid will be more prominent.
## 6 Discussion
### Threats to Validity
#### 6.1.3 External validity  
The first external threat to validity is that all software components included in the study are open-source software systems. Consequently, they may not be representative of all closed-source software from the industrial domain. Open source software is developed in development environments that could have different expectations regard coding conventions and quality standards. To reduce concern regard non-professional software projects, our research is based on the list of the highly-accepted software components. Software components used in the study are among the leaders in their field, provided by in IT world recognized software vendors and developed mainly by professional software developers sponsored by these vendors or communities.  
The second external threat to validity is that all software components are implemented based on Java technology stack. Other programming languages, e.g., C++, Smalltalk, and Python, used in the development of modern software solutions, may have features that differ from those in Java. Despite these differences, all modern mainstream programming languages in their foundation follow the same principles, resulting in the minimal impact of programming language on software maintainability.  
The third external thread to validity is that the software components used in the study may not be representative of other every-day real-life software projects. The experiment was conducted on real-life software components that are incorporated into many production-ready software solutions daily, but are already well maintained and audited by several experienced developers. This may not be the case for every software project in the industry, and thus the conclusions of our study should be taken with precaution.