esa-sceva/satcom-chunk-collection huggingface dataset:
# Ozone Activation on TiO\({}_{2}\) Studied by IR Spectroscopy and Quantum Chemistry
## 5 Conclusions  
The adsorption of different isotopic ozone mixtures on TiO\({}_{2}\) at 77K studied by FTIR spectroscopy, in addition to the weakly bound molecules with band positions close to those of free or dissolved molecules, revealed chemisorbed species with well-shifted vibrational frequencies. The anharmonicity, i.e., the difference between the sum of the frequencies of \(\
u_{1}\) and \(\
u_{3}\) modes and the band position of \(\
u_{1+3}\) combination vibration, diminished from about 35 cm\({}^{-1}\) for the gas down to zero. Unlike gaseous or weakly perturbed molecules, where the combination band of isotopically mixed ozone split in six components, the \(\
u_{1+3}\) band of chemisorbed species split into eight maxima of different isotopomers, thus showing that the two terminal oxygen atoms were no longer equivalent. The intensity distribution of the components in the spectra of isotopic mixtures with different enrichments enabled us to identify all the eight species on the assumption of a monodentate model. These new data confirmed by calculations, in addition to the existing basic knowledge, can be used in promising experiments on infrared laser-induced resonance photoozonolysis reactions [16].  
DFT calculations of clusters modeling 2-, 4-, or 5-coordinated Ti\({}^{4+}\) cations showed that on all these sites 2 stable configurations were possible: monodentate and what we called bidentate. The latter was symmetric and energetically favorable only for hypothetical structure with two-coordinated titanium. In bidentate complexes with four- or five-coordinated Ti\({}^{4+}\) cations, two bonds differed in their length and, apparently, in force constants. The frequencies of all the isotopic modifications of ozone molecule which formed monodentate or bidentate complexes with four- or five-coordinated titanium atoms were calculated and compared with those of experimentally observed spectra. The four considered complexes adequately reproduced the splitting of the \(\
u_{1+3}\) combination vibration band and the lowered anharmonism of chemisorbed O\({}_{3}\). The energetically most favorable monodentate complex with four-coordinated titanium atoms showed good agreement with the observed spectra; however, the distance between the frequencies of \(\
u_{1}\) and \(\
u_{3}\) vibrations was greater than that in the experiment. To further understand the mechanism of ozone adsorption and decomposition on titanium dioxide, molecule interactions with the adjacent cations of dual sites should be considered.  
Conceptualization, I.K. and A.T.; methodology, I.K.; investigation, T.A. and O.P.; data curation, I.K. and A.T.; writing--original draft preparation, A.T.; writing--review and editing, A.T. and O.P.; visualization, T.A. and O.P.; supervision, A.T. All authors have read and agreed to the published version of the manuscript.  
The work was supported by Russian Foundation for Basic Research, grant No. 19-33-90296.  
Not applicable.
# Public Key-Based Authentication and En-Route Filtering Scheme in Wireless Sensor Networks
## 4 The Proposed Scheme
### Scheme Overview
#### 4.1.4 Design of Mechanism for Malicious Nodes Detection and Isolation  
To mitigate the impact of malicious nodes, the authors propose a trust value-based approach to identify and isolate the malicious nodes in the network. Each node establishes an empty isolation list and a trusted neighbor list to store the trust values of its neighbors, in which the trust values of all its neighbors are initialized to 1. The trust value of a node decides whether this node will be selected to participate in report generation or forward the reports. A node is considered to be trusted if its trust value is higher than the predefined threshold \(T_{Tv}\); otherwise, it is suspicious. When a node \(v_{i}\) detects malicious behavior of its neighbor \(v_{k}\), it will decrease the trust value of \(v_{k}\) (denoted as \(TV_{k}\)) in its trusted neighbor list. When \(v_{i}\) finds that \(TV_{k}\) drops below \(T_{Tv}\), then \(v_{i}\) will delete \(v_{k}\) from the trusted neighbor list and add it into the isolation list to isolate it (\(v_{i}\) will not transmit any message to \(v_{k}\) or process any message from it).  
The reduction in trust values according to different malicious behaviors can be described as follows:  
* During the report generation phase, if a participating node \(v_{j}\) refuses to provide \(k_{j}P\) or a partial signature, or provides an incorrect partial signature, then each cluster node will deduct 0.2 from \(TV_{j}\), and \(v_{j}\) will be substituted.
* During the report generation phase, if the CH node \(v_{i}\) refuses to broadcast \(X(R)\), or maliciously accuses any participating node of not providing \(k_{j}P\) or a partial signature, or providing an incorrect partial signature, or \(v_{i}\) refuses to send out the signed report, or sends out a report with an incorrect cluster signature, then each cluster node will deduct 0.2 from \(TV_{i}\), and a new CH node will be selected to regenerate a signed event report.
* If a forwarding node \(v_{t}\) detects a false report sent by \(v_{k}\), then \(v_{t}\) will deduct 0.1 from \(TV_{k}\).
* If a forwarding node \(v_{t}\) maliciously refuses to forward the report from \(v_{k}\), then \(v_{k}\) will deduct 0.1 from \(TV_{t}\).
* If a cluster node \(v_{k}\) transmits a forged report with an incorrect cluster signature to the forwarding node \(v_{t}\), then \(v_{t}\) and each cluster node will deduct 0.1 from \(TV_{k}\).  
Note: (1) The first two malicious behaviors are more serious than the others, so a higher value should be deducted from the trust value of the malicious node correspondingly. (2) The reduction of trust value for a malicious behavior can be set according to the requirement of a specific application. As an example, if the network has low security requirements, a small value (0.02 for example) can be deducted from the trust value for a malicious behavior.  
Next, the scheme will be introduced in detail.
## 2 Materials and Methods
### Modeling for Yield Estimation  
Regression analysis was conducted between county-level crop yields and MODIS EVI2 to study the explanatory capability of time-series EVI2 for mapping regional yield variability. A linear model was used because vegetation indices are considered to be linearly related to crop photosynthetic capacity [40; 41], which can be used to model crop biomass accumulation and yield [13; 28; 42; 43]. In our earlier study, NDVI was correlated with crop yields to investigate its capability for county level yield estimation [44]. In this study, linear correlation analysis was conducted between crop yields and EVI2 for all years combined (all-year model) and for each year individually (year-specific) in three agricultural regions separately. For the all-year model, year was treated as an additional variable to account for the long term trends of yields, thus a multiple linear regression model was adopted:  
\[Y=a_{0}+a_{1}EVI2+\ a_{2}\ A \tag{2}\]  
where \(Y\) is county level yield; \(EVI2\) represents county level average derived with a crop mask for a given time in the growing season; \(A\) is the year; and \(a_{0}\), \(a_{1}\), and \(a_{2}\) are regression coefficients. Although an all-year model was desirable, we conducted a year-specific regression to investigate the inter-annual variability of the relationships between crop yields and EVI2.  
The coefficient of determination (\(R^{2}\))--also defined as the Nash-Sutcliffe model efficiency coefficient--the root mean square error (RMSE), and the mean relative absolute error (MRAE) were calculated to assess the correlation between yield and EVI2 and the performance of the regression models:  
\[R^{2}=1-\sum_{i=1}^{n}(Y_{io}-Y_{ie})^{2}/\sum_{i=1}^{n}(Y_{io}-\bar{Y}_{o})^{ 2}, \tag{3}\]  
\[\text{RMSE}=\sqrt{\sum_{i=1}^{n}(Y_{io}-Y_{ie})^{2}/n}, \tag{4}\]  
\[\text{MRAE}=(\sum_{i=1}^{n}\lvert Y_{io}-Y_{ie}\rvert/Y_{io})/n, \tag{5}\]  
where \(Y\) represents yield, \(o\) indicates reported yields and \(e\) indicates estimated yields, \(i\) represents an individual sample (of a county in a year), and \(n\) is the total number of samples. Relative RMSE (RRMSE) was calculated as percentage to the mean crop yields.
## 2 Materials and Methods  
### Experimental Design  
The design of the experiment is divided into two parts: First, a simulation of the fruit thinning and pesticide spraying activities is conducted in the laboratory; Then, after verifying that the PULE can safely and effectively reduce muscle tension in arm-lifting activities, the PULE is worn to perform the actual operation of pesticide spraying on a pomelo tree and fruit thinning of a juibube tree.  
* In the laboratory: Two common arm-lifting movements were simulated (fruit thinning and pesticide spraying) in the laboratory, and the participants were divided into groups A (25-40 yr.) and B (41-64 yr.) to compare the PULE effect in different age groups. Because this test was the first evaluation of the PULE, for safety reasons, the test movements were limited to simple short-term lifting exercises of the arms. The independent variables were the ages of groups A and B, two types of arm-relatedactivities, namely, fruit thinning and pesticide spraying, and the use of the PULE (with PULE: ES, without PULE: W-ES). In this experimental design, the main muscle used to lift the upper limb and perform internal rotation was the AD muscle. Therefore, we measured electromyography (EMG) signals only for the AD. The dependent variables were the EMG of the AD, the lifting angle of the upper limb (\(\theta\)), and the ratings of perceived exertion (RPE) of the upper limb. Additionally, the local perceived pressure (LPP) was rated for the ES condition. The experiment considered four conditions (the lifting movements of the fruit thinning and pesticide spraying activities, W-ES, and ES), which were implemented by each participant. Two forms of arm activity (fruit thinning and pesticide spraying) were selected, as they are commonly performed during orchard farming.
* In the orchard: After confirming that the PULE can effectively and safely assist arm lifting in the laboratory, the farmers then performed the real operation of pesticide spraying for the pomelo tree and fruit thinning for the jujube tree. The independent variables were the use of the PULE (with PULE: ES, without PULE: W-ES). The dependent variables were the RPE of the upper limb and the EMG of the AD, lateral deltoid (LD), and posterior deltoid (PD). Additionally, the LPP was rated for the ES condition. In this experimental design, pesticide spraying and fruit thinning are continuous complicated actions that include internal rotation, abduction, and external rotation. The main muscles used to lift the upper limbs and undergo internal rotation, abduction, and external rotation were the AD, LD, and PD. Therefore, we measured the EMG signals for the AD, LD, and PD.
## 4 Results
### Theoretical Basis for the Experiments Being Developed (QR2)  
The main objective of the selected research is to analyse students' attention and/or concentration level in order to improve learning, as stated in QR2. For this reason, the studies are based on theoretical theories of attention and learning.  
[PERSON] et al. [43], for example, build on [PERSON] [44], who argues that learning styles can be defined as cognitive, affective, and physiological characteristics that indicate how individuals interact with and respond to learning environments. [PERSON] and [PERSON] base their theoretical framework on [PERSON] and [PERSON]'s [45] information processing theory of self-regulated learning (SRL). [PERSON] et al. propose that the use of an interactive learner feedback system can help increase learner concentration [46]. [PERSON] et al. [47] base their work on the possibility of recognising students' affective states in order to accordingly adapt teaching methodologies, as do [PERSON] et al. [48] and [PERSON] et al. [14], who specifically focus on emotions. This is also the case in the study by [PERSON] and [PERSON] [58], who also refer to cognitive states.  
Methodological Designs and Types of Experiences Proposed to Implement These Types of Experiences (QR3)  
According to QR3, it has been observed that the methodological designs used were fundamentally experimental and grounded in mechanical observation through technological elements, with data analysis based on artificial intelligence. The participants analysed (students) were exposed to various educational activities to measure the indicators that allow their levels of attention and/or concentration to be estimated and predicted.  
On the other hand, it has also been noted that several studies were applied in specifically designed contexts, either because the technology to be used for measurement required it, as with the use of electroencephalography or other elements [42, 52], or to facilitate the performance of the experiments [45]. Other investigations were carried out in real classroom conditions with the intention of collecting information during their standard development [49], mostly with small samples ranging from three or four cases [51] to classrooms of thirty to fifty students [49], although some studies used larger samples [61].  
Similarly, it can be seen that several studies also combined data collection using technological devices with various questionnaires and tests to cross-check the data [14].  
Finally, in response to QR3, it should be noted that research was been carried out at different educational levels from primary [48; 50; 63; 65], secondary [43; 44; 46], or university levels [45; 47] and, in some cases, also involving teachers [50; 58].
# Development and Testing of a Two-UAV Communication Relay System
## 4 Software Development
### Data Framing for Communication Relay  
To facilitate the communication relay, the messages and data to be exchanged between the UAVs and GCS were grouped into frames, the format of which is shown in Figure 10. Each communication node (\"Mom\", \"Son\", and GCS) was given a unique ID. The header of the frame contained two fields, \"Source ID\" and \"Target ID\". \"Source ID\" indicated the node from which the frame was transmitted, and \"Target ID\" indicated the target receiver of this frame. This mechanism enabled the identification of the sender and receiver of a data frame, which was important to the realization of frame routing.
## 4 Experiments
### Technological Challenges  
The SAR-IoCA architecture was developed to obtain an effective integration of human agents (Figure 8) and robots (Figure 9) in search and rescue operations. In the deployment of SAR-IoCA in these experiments, distinctive technological challenges (TC) were identified:  
1. [label=TC0]
2. Launching the ROS nodes (via UMA-ROS-Android) from the 5G smartphone attached on the UAV (Figure 9) to transmit the images of the terrain. This TC is related to a smartphone acting as a local edge within the ROS node network.
3. Monitoring by subscribing to the ROS topics of interest from the MEC centers (BCC and FCC), to explore the environment through the images captured by the UAV. This TC is related to local edges and cloud edges within the ROS node network within ROS-FIS.
4. Tessellation in the cloud using the aerial images published by the UAV. This TC is linked to the cloud part of the ROS network within ROS-FIS.
5. Victim detection by means of BLE transceivers. This TC requires local edges and cloud edges in SAR-FIS to process and synchronize the internal databases associated with the H-WTN BLE. The UAV and UGVs Cuadriga and Rambler (Figure 9,b) carried BLE scanners.
6. Autonomous navigation and teleoperation of UGVs. This TC requires local edges and cloud edges within SAR-FIS to process the teleoperation and the path-planning request by the user. For the case of our robots, Cuadriga and Rambler were managed and monitored in SAR-FIS.
7. Path planning reacting to sensory events associated to risks in the terrain using the LoRa H-WSN belonging to our H2 WTN. This TC needs local edges and cloud edges in  
Figure 8: Firefighters and military emergency unit (UME) assisting casualties.  
SAR-FIS to detect sensory events triggered by the LoRa H-WSN and process the path planning according to their location and relevance. The path planning may include several UGVs.
* Transmission of data acquired by physiological sensors placed on the members of the human rescue team. This TC involves external sensors linked to a smartphone via Bluetooth. For this SAR exercise, a firefighter was the subject who wore the sensors. The communication between the 5G smartphone and the MEC centers was conducted via 5G to monitor the firefighter's health conditions.  
The performance of SAR-IoCA during the exercise in relation with these challenges is discussed in the next section.
# Image Recovery with Data Missing in the Presence of Salt-and-Pepper Noise
## 6 Conclusions  
In this work, a joint estimation method of image recovery, salt-and-pepper noise suppression and data missing patter estimation are developed. Due to reformulations performed for the noise and the data missing, they are represented by the sparse signals in the time domain. This property is utilized to actively suppress the noise and perform missing pattern estimation. In order to achieve image recovery in the presence of salt-and-pepper noise and data missing, a joint estimation is developed that allows for simultaneously recovering the image, suppressing the noise, and estimating the unknown missing pattern. The resultant joint estimation is an optimization problem and it is efficiently solved by ADMM and APG based solvers. From the experiments conducted, the proposed joint estimation approach generates a significant performance improvement compared with other state-of-the-art algorithms.  
H.L. conceptualized the idea; Z.L. and Y.Z. derived the method; L.H. and X.J. wrote the software and conducted the experiments; H.L. and T.-K.T. wrote and proofread the paper.  
This work was jointly supported by the National Natural Science Foundation of China under Grants 61501072 and 61801066, by the Program for Changjiang Scholars and Innovative Research Team in University under Grant IRT16R72, by the special fund of Chongqing Key Laboratory, and by the Innovation Project of the Common Key Technology of Chongqing Major Industry under Grant cstc2017 zdcyzdyK0021.  
The authors express their appreciations to Raymond Honfu Chan, The Chinese University of Hong Kong, and Yiqiu Dong, Technical University of Denmark, for providing the code of AM-IEPR used in this paper. The codes of BPFA and FoE are downloaded from authors' website, and we owe them a great gratitude.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Salt-and-Pepper Noise+Missing** & **20\% + 20\%** & **30\% + 30\%** & **40\% + 40\%** \\ \hline framelet+APG & 0.994 & 0.988 & 0.982 \\ framelet+ADMM & 0.815 & 0.742 & 0.686 \\ wavelet+APG & 0.931 & 0.879 & 0.859 \\ wavelet+ADMM & 0.784 & 0.716 & 0.597 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Structural similarity index (SSIMs) for the lena image with different levels of salt-and-pepper noise and data missing.  
Figure 12: Restoration results of different algorithms under both salt-and-pepper noise and specific data missing. (**a**) corrupted image with 20% salt-and-pepper and 21.4% specific missing; (**b**) reconstructed image obtained by framelet+APG; (**c**) reconstructed image obtained by framelet+ADMM; (**d**) reconstructed image obtained by wavelet+APG; (**e**) reconstructed image obtained by wavelet+ADMM.
# Image Watermarking Scheme Using LSB and Image Gradient
## 4 Experimental Results  
In this section, to check the performance of proposed scheme, MATLAB-2017 software on a computer with sixth generation Windows 10 and 8 GB RAM was used to conduct tests on standard images taken from the SIPI Image Database at the University of Southern California ([[http://sipi.usc.edu/database/](http://sipi.usc.edu/database/)]([http://sipi.usc.edu/database/](http://sipi.usc.edu/database/)), accessed on 22 March 2022). Grayscale testing images Lena and Baboon with a standard size of 512 \(\times\) 512 and a 32 \(\times\) 32 grayscale logo as a watermark signal were used. To observe the imperceptibility and robustness of the testing images, several experiments were performed by varying the intensities of the image processing attacks and geometrical attacks.
# A Comprehensive Review of the Application Characteristics of Biodiesel Blends in Diesel Engines
## 1 Introduction
The lubricity of fuel is essential to fuel injectors and oil pumps, and it helps reduce the friction loss of the fuel system under high temperature, high pressure and high speed conditions [17]. In fuel injectors, good lubricity of the fuel ensures smooth movement of plungers, tappets, and needle valves. Although most researchers [18; 19; 20] have reported that the lubricity of biodiesel is excellent, it also has problems such as oxidative degradation and corrosion. The degradation of biodiesel may generate oxidation products such as acids, alcohols, aldehydes, and polymers, which will block the fine pores of filters and nozzles and can also challenge the corrosion resistance of fuel supply system materials. However, this also reflects the better degradability of biodiesel. At this stage, the specific impact of biodiesel compatibility on vehicle engines is mostly based on laboratory tests, and actual long-term road tests are still scarce. This study refers to more than one hundred papers during the past ten years and summarizes their direct impacts, including engine performance, combustion and emission characteristics containing the analysis of VOCs and PAHs, and indirect effects including vibration and noise, compatibility along with the causes of these observations. The purpose of this work is to provide an exhaustive overview of the impact of biodiesel as an alternative fuel in diesel engines, highlight the advantages and disadvantages of biodiesel compared to traditional fossil diesel in application, which may provide a more complete picture of biodiesel as an alternative fuel.
## 3 Results and Discussion
### Crossover  
Table 5 showcases the dimensions of the crossover that were calculated and optimized using [61]. Various parameters were adjusted during the optimization process. Figure 12 shows the S-parameters of the designed crossover, which demonstrate good performance and a high level of isolation. It illustrates that the S-parameters S11, S12, and S14 exhibit minimal reflection at ports 1, 2, and 4, respectively, indicating effective impedance matching and signal transmission. These results are consistent with established optimization processes in antenna design, where minimized S-parameters are crucial for ensuring efficient signal transmission and minimizing interference, as noted by [PERSON] [78] and [PERSON] et al. [79].  
Figure 11: Phase difference in the 90\({}^{\circ}\) hybrid branch line coupler for input port 1.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameters** & **Calculated** & **Optimized** \\ \hline Length (50 \(\Omega\)) & 9.97 mm & 7.3 mm \\ Length (35.355 \(\Omega\)) & 9.82 mm & 7.3 mm \\ Length (25 \(\Omega\)) & 9.69 mm & 7.3 mm \\ Width (50 \(\Omega\)) & 2.42 mm & 2.42 mm \\ Width (35.355 \(\Omega\)) & 3.95 mm & 3.95 mm \\ Width (25 \(\Omega\)) & 6.17 mm & 4 mm \\ \hline \hline \end{tabular}
\end{table}
Table 5: Dimensions and parameters of the crossover.