esa-sceva/satcom-chunk-collection huggingface dataset:
# Lightweight Integrity Preserving Scheme for Secure Data Exchange in Cloud-Based IoT Systems
## 6 Proficiency Evaluation
### Cost of Communication  
The communication cost between the semi-trust server and the IoT-cloud system server, which consists of the challenge and the proof, is further examined in this section. This study reviewed the batch integrity checking between smart device users and IoT-cloud systems. For the sake of comparison, it was assumed that the number of challenged files from each smart device user using different IoT-cloud systems was the same.  
When reviewing [PERSON]'s scheme [7] on each of the IoT-cloud system servers, it was clear that there was a linear relationship between the communication cost of the challenge data and the number of challenged data blocks from each smart device user. There can be many data blocks in a large-scale IoT-cloud system, which means that [PERSON]'s system [7] may result in a high communication cost. Alternatively, in the proposed solution the communication cost has a linear relationship only to the number of challenge requests that the semi-trust server sends to the IoT-cloud system at CK = 128 bits.  
Therefore, the results prove that the proposed solution is more cost-effective than [PERSON]'s scheme [7].
## 4 Discussion
### Error Analysis Between Analytical Solutions and Numerical Simulations
Since the central cell only exchanges heat with adjacent cells, \(h\) can be considered proportional to \(K_{cell}\). In other words, \(h=h_{0}\times K_{cell}/K_{cell0}\), where \(h_{0}\) and \(K_{cell0}\) represent the heat transfer coefficient and the thermal conductivity between cells under the baseline conditions, respectively. As \(K_{cell}\) increases, the heat coupling between the central cell and adjacent cells becomes stronger. That is, for sufficiently large \(K_{cell}\), the two cells are effectively integrated, and the effective thermal capacity doubles. In order to represent this \"strength of coupling between cells\" in terms of heat diffusion length \(L\), it can be expressed as follows:  
\[\frac{L}{L_{0}}\approx\frac{\sqrt{K_{cell}/\rho C_{p}t}}{\sqrt{K_{cell0}/\rho C _{p}t}}=\sqrt{K_{cell}/K_{cell0}} \tag{34}\]  
Therefore, the effective thermal capacity \(\rho C_{p}\) can be written as follows:  
\[\rho C_{p}\propto\sqrt{K_{cell}/K_{cell0}} \tag{35}\]  
Since the temperature rise term in Equation (12) is \(\exp(-ah/\rho C_{p})\), considering the changes in \(K_{cell}\) and thermal capacity \(\rho C_{p}\), the effective heat transfer coefficient is as follows:  
\[h=\frac{K_{cell}}{K_{cell0}}\frac{h_{0}}{\sqrt{K_{cell}/K_{cell0}}}=h_{0}\sqrt{ K_{cell}/K_{cell0}} \tag{36}\]  
Figure 11a shows the relationship between \(K_{cell}/K_{cell0}\) and the adjusted \(h/h_{0}\), as well as the equation above. It is confirmed that the expression in Equation (36) generally reproduces the adjusted values of h.  
As well as the heat transfer coefficient \(h\), the \(K_{cell}\)-dependence of the temperature frequency \(f\) is considered. Using the heat diffusion length \(L\), the relaxation time \(\tau\) is given by \(\tau=\rho C_{p}K_{cell}L^{2}\propto K_{cell}\), which implies that the frequency \(f\) is inversely proportional to \(K_{cell}\). \[\frac{f}{f_{0}}=\frac{K_{cell}}{K_{cell0}} \tag{37}\]  
Figure 11: (**a**) Relationship between \(K_{cell}/K_{cell0}\) and the adjusted \(h/h_{0}\) and (**b**) relationship between \(K_{cell}/K_{cell0}\) and the adjusted \(f/f_{0}\). where f0 represents the \(f\) value in the baseline condition. Figure 11b shows the relationship between \(K_{cell}\)/\(K_{cell0}\) and the adjusted \(f/f_{0}\), as well as the plot from Equation (37). One can see that the expression in Equation (37) agrees well with the adjusted values, indicating that the above qualitative modeling demonstrates that there are no contradictions.
## 7 Conclusions  
This paper explores the influence of the underwater vehicle discharge port structure on thermal jet infrared characteristics by means of simulations and experiments. The oval discharge port is designed, the radius ratio of the discharge port is changed and the perimeter of the discharge port contact surface is increased. Moreover, the discharge multiport is further designed, the number of discharge ports is increased and the distribution of discharge ports is adjusted. According to the research results, the following conclusions are drawn:  
1. As the radius ratio of the discharge port becomes smaller, the thermal jet mixing contact surface becomes larger, the thermal jet mixing heat transfer effect becomes better and the infrared characteristics of the thermal jet becomes less obvious.
2. As the radius on the Z-Axis of the discharge port becomes smaller, the width of the thermal jet at the outlet becomes narrower, and the floating height of the thermal jet becomes lower.
3. Increasing the number of discharge ports and reducing the gap between the discharge ports are conducive to accelerating the thermal jet temperature attenuation process and reducing the maximum temperature difference in the temperature center formed by the thermal jet on the water surface.
4. When the discharge ports are distributed on both sides of the underwater vehicle, the coiling and mixing phenomenon between the discharge ports disappears, the thermal jet temperature attenuation process speeds up and the characteristics of the temperature diffusion region formed on the water surface are less obvious.
5. The structure of the discharge port has a significant influence on the infrared characteristics of the thermal jet. Changing the shape, number and distribution location of the discharge port is beneficial for improving the thermal stealth performance of the underwater vehicle.  
Through this study, the idea and basis for an actual underwater vehicle discharge port design are provided.  
Conceptualization, C.G.; Data curation, C.G.; Formal analysis, C.G.; Funding acquisition, Y.D. and L.Y. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors declare no conflict of interest.
# Radiation Qualification by Means of the System-Level Testing: Opportunities and Limitations
## 4 Limiting Factors of Qualification  
Although there are interesting opportunities given by the system-level testing, performed experiments let also point out the crucial limitations in terms of system qualification by system-level test only. The most relevant results are presented in this section. Specific remarks for SEE and TID test cases will be given.
###### Abstract  
On the road towards 5G, a proliferation of Heterogeneous Networks (HetNets) is expected. Sensor networks are of great importance in this new wireless era, as they allow interaction with the environment. Additionally, the establishment of the Internet of Things (IoT) has incredibly increased the number of interconnected devices and consequently the already massive wirelessly transmitted traffic. The exponential growth of wireless traffic is pushing the wireless community to investigate solutions that maximally exploit the available spectrum. Recently, 3 rd Generation Partnership Project (3 GPP) announced standards that permit the operation of Long Term Evolution (LTE) in the unlicensed spectrum in addition to the exclusive use of the licensed spectrum owned by a mobile operator. Alternatively, leading wireless technology developers examine standalone LTE operation in the unlicensed spectrum without any involvement of a mobile operator. In this article, we present a classification of different techniques that can be applied on co-located LTE and Wi-Fi networks. Up to today, Wi-Fi is the most widely-used wireless technology in the unlicensed spectrum. A review of the current state of the art further reveals the lack of cooperation schemes among co-located networks that can lead to more optimal usage of the available spectrum. This article fills this gap in the literature by conceptually describing different classes of cooperation between LTE and Wi-Fi. For each class, we provide a detailed presentation of possible cooperation techniques that can provide spectral efficiency in a fair manner.  
LTE; Wi-Fi; cooperation; coexistence; cognitive radio; spectral efficiency; fairness +
Footnote †: journal: Sensors
# Variable Structure PID Controller for Satellite Attitude Control Considering Actuator Failure
## 1 Introduction
System performance is largely improved by implementing the proposed method. In addition, [PERSON] [20; 21; 22] and [PERSON] [23; 24; 25; 26] designed satellite attitude controllers for fast attitude maneuver, but the actuator failures were not taken into consideration. Hence, in this paper, a variable structure PID controller with fault tolerant capability was proposed for satellite attitude control to improve the system convergence rate and robustness.
# Application of Machine Learning to Assess the Quality of Food Products--Case Study: Coffee Bean
## 2 Materials and Methods
### Statistical Analysis  
In the study, the homogeneity of coffee beans by research class was carried out using analysis of variance (ANOVA), and [PERSON]'s test [46] was applied to more accurately depict mean values between coffee classes using Statistica version 13.3 (Statsoft, Tulsa, OK, USA). Averages for each coffee class were calculated. The critical value of the Tukey test was set at a significance level of \(\alpha\) = 0.05. The ranges of differences for each class of coffee bean were calculated and compared. As a result, statistical analysis made it possible to accurately assess significant differences between the coffee classes studied. This translated into the extraction of significant characteristics of each coffee class and the establishment of detailed homogeneity for these classes.
## 3 Results and Discussion
### Optical Properties
When a silicon atom is the glass-forming element and lead acts as the modifier, the electronic structure of the glasses changes radically [39]. For high-lead glass samples, optical absorption, mostly induced by electronic transitions between states of oxygen and lead atoms (O2p \(\rightarrow\) Pb6p), has narrow band gaps, and for samples containing less than 50 mol\(\%\) PbO\({}_{2}\), the UV edge of fundamental absorption formed by intracenter transitions of Pb\({}^{2+}\) ion has wide band gaps, which is typical for insulators [40]. The Urbach energy is also sensitive to structural rearrangement in the glassy matrix. For crystalline systems, the \(\rm E_{U}\) values ranged between 0.046 and 0.066 eV [41]. The lower value, \(\rm E_{U}=0.150\) eV, was obtained for sample S4 and indicates the decrease in the structural disorder in the glass matrix. The decrease in \(\rm E_{U}\) values is due to polymerization, which reduces the density of localized states and their tails in the band gap [42]. As observed from the Urbach energy analysis, the disorder of the glassy matrix increases slowly in the S5 sample due to the increase in the localized state concentration included in the energy gap.
## 4 Conclusions  
In this work, based on the molecular dynamics method, an electrode-electrolyte model is established to numerically investigate the molecular-level structure in the electrical double layers of the [EMIM]\({}^{+}\)/[BF4]\({}^{-}\) ionic liquid on the vertically oriented graphene electrode. The detailed distribution and migration of the ions on the non-rough and rough electrode surfaces with different charge densities are compared and analyzed. In addition, the C-V curve of the EDL is obtained to clarify the effect of the electrode surface morphology on the capacitance of the EDL. The main conclusions can be summarized as follows:  
1. The concentration profiles of ions exhibit periodical oscillations with decaying amplitude along the direction perpendicular to the charged/uncharged electrode surface, which suggests an alternate distribution of anions and cations in several consecutive layers in the EDL on the electrode surface. When the electrode is charged, the alternate layers of [BF4]\({}^{-}\) anions experience  
Figure 9: Correlation between the capacitance and the potential drop across the EDLs on the rough and non-rough electrodes.  
more-significant migration than the layers of [EMIM]\({}^{+}\) cations, owing to the good mobility of the [BF\({}_{4}\)]\({}^{-}\) anion due to its small size and steric effect. Additionally, these ion layers can be extended deeper into the bulk electrolyte solution by the stronger interaction of the rough electrode compared to the situation for the non-rough electrode.
2. The potential energy valley of ions near the neutral electrode surface establishes a potential energy difference to compensate the energy cost of the ion accumulation. As a result, ions are able to accumulate in the location of the valley to form the first layers near the electrode, allowing the potential drop across the EDL on the uncharged electrode surface to be produced.
3. Due to the greater effective contact area between the ions and electrode, the rough electrode possesses a larger capacitance than the non-rough one when it is negatively and positively charged. In addition, when the electrode is charged, it is harder for the larger-sized [EMIM]\({}^{+}\) cations to accumulate in the narrow grooves on the rough electrode when compared with the smaller [BF\({}_{4}\)]\({}^{-}\). Consequently, when compared with the symmetric double-hump-shaped C-V curve for the non-rough electrode surface, the double-hump-shaped C-V curve for the rough electrode is asymmetric, where the capacitance is increased more significantly when the electrode is positively charged.  
The authors gratefully acknowledge the support provided by the National Natural Science Foundation of China (51406175) and the Natural Science Foundation of Jiangsu Province (BK20140488).  
[PERSON] provided the guidance and supervision. [PERSON] implemented the main research, discussed the results, and wrote the paper. [PERSON] and [PERSON] checked and revised the paper. All authors read and approved the final manuscript.  
The authors declare no conflict of interest.
# Design and Fabrication of a MEMS Bandpass Filter with Different Center Frequency of 8.5-12 GHz
## 4 Conclusions  
In this study, we designed and simulated an RF MEMS filter for applications within the 8.5-12 GHz range. Eight center frequencies were selected within this frequency to carry out a series of device design simulations. The simulation results showed a filter insertion loss of \(\leq\)1.27 dB and a stopband rejection of \(\geq\)25 dB. In order to evaluate the MEMS filter design methodology, a filter worked at 10.5 GHz was fabricated with an aluminum top electrode, which had a low insertion loss of 1.12 dB and a high stopband rejection of 28.3 dB. Compared with the simulation results, the proposed filter has better electrical performance, including less isolation and stopband rejection. The proposed filter thus provides lower insertion losses and higher stopband rejection than the traditional filter.  
Conceptualization, Y.-F.Z. and M.C.; methodology, Y.-F.Z.; software, Y.-F.Z.; validation, Y.-F.Z., D.-P.W. and M.C.; formal analysis, M.C.; investigation, Y.-F.Z.; resources, D.-P.W.; data curation, Y.-F.Z.; writing--original draft preparation, Y.-F.Z.; writing--review and editing, D.-P.W.; visualization, M.C.; supervision, D.-P.W.; project administration, D.-P.W.; funding acquisition, D.-P.W. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the National Natural Science Foundation of China (61974034).  
Not applicable.  
The authors declare no conflict of interest.
# Low-Complexity Hybrid Optical OFDM with High Spectrum Efficiency for Dimming Compatible VLC System
## Appendix A  
According to the definition of the upper-clipping, the upper-clipped PAM-DMT signal can be re-written as:  
\[\left[y_{PAM,n}\right]_{c}=\frac{y_{PAM,n}-\left|y_{PAM,n}\right|}{2}. \tag{1}\]  
Upon taking the \(N\)-point FFT of signal \(\left[y_{PAM,n}\right]_{c}\), we can get:  
\[\begin{split} Y_{k}^{c}&=\sum_{n=0}^{N-1}\left[y_{ PAM,n}\right]_{c}\exp\left(-j\frac{2\pi nk}{N}\right)\\ &=\frac{1}{2}\underbrace{\sum_{n=0}^{N-1}y_{PAM,n}\exp\left(-j \frac{2\pi nk}{N}\right)}_{W_{1}}-\underbrace{\frac{1}{2}\sum_{n=0}^{N-1} \left|y_{PAM,n}\right|\exp\left(-j\frac{2\pi nk}{N}\right)}_{W_{2}}.\end{split} \tag{2}\]  
It can be found that the first term \(W_{1}\) in (2) is the FFT results of the unclipped signal \(y_{PAM,n}\), which is the original transmitted PAM-DMT symbols carried by the imaginary parts of the even-indexed subcarriers. The second term of \(W_{2}\) is viewed as the interference, imposed by the upper-clipping operation. Recall the property of \(y_{PAM,n}=y_{PAM,n+N/2}=-y_{PAM,N/2-n}=-y_{N-n}\)[14], the second term of (2) can be re-written as:  
\[\begin{split} W_{2}&=\frac{1}{2}\sum_{n=1}^{N/4-1} \left[\left|y_{PAM,n}\right|\exp\left(-j\frac{2\pi nk}{N}\right)+\left|y_{PAM,N/2-n}\right|\exp\left(-j\frac{2\pi(N/2-n)k}{N}\right)\right.\\ &\quad\left.+\left|y_{PAM,N/2+n}\right|\exp\left(-j\frac{2\pi(N/ 2+n)k}{N}\right)+\left|y_{PAM,N-n}\right|\exp\left(-j\frac{2\pi(N-n)k}{N} \right)\right]\\ &=\frac{1}{2}\sum_{n=1}^{N/4-1}\left|y_{PAM,n}\right|\left\{ \left[1+\exp(-j\pi k)\right]\left[\exp\left(j\frac{2\pi nk}{N}\right)+\exp \left(-j\frac{2\pi nk}{N}\right)\right]\right\}.\end{split} \tag{3}\]  
Since we have  
\[\exp(-j\pi k)=\left\{\begin{array}{ll}-1,&\text{$k$ is odd-valued}\\ 1,&\text{$k$ is even-valued}\end{array}\right., \tag{4}\]  
the second term \(W_{2}\) can be further expressed as:  
\[W_{2}=\left\{\begin{array}{ll}0,&\text{$k$ is odd-valued}\\ \sum_{n=1}^{N/4-1}\left|y_{PAM,n}\right|\cos\frac{2\pi nk}{N},&\text{$k$ is even-valued}\end{array}\right., \tag{5}\]Upon observing, it can be easily found that the introduced interference caused by the upper-clipping falls only on the real parts of the even-indexed subcarriers, where the odd-indexed subcarriers and the imaginary parts of the even-indexed subcarriers are free of contamination. As a benefit, the proposed DCHO-OFDM scheme is capable of remaining uncorrupted by the upper-clipped PAM-DMT signal.
## 3 Results and Discussion
### The Comparison of Lp_HOGS with Lp_LOGS
#### 3.1.1 The Gaussian Blur  
The noise was generated by the MATLAB built-in function \"noise (I, type, parameters)\". For example, 30% of the salt-and-pepper noise was set to noise (I,'salt & Pepper', 0.3). We included 30%, 40%, and 50% of the salt-and-pepper noise in the test images with a 7 \(\times\) 7 Gaussian blur. The experimental results are summarized in Table 1.  
The three performance indicators obtained by the Lp_HOGS model were higher than those of the Lp_LOGS model; thereby demonstrating that the proposed method achieved better deblurring and denoising effects. The Lp_HOGS model achieved average PSNR values that were 0.304, 0.784, and 1.287 dB higher than those of the Lp_LOGS model when the salt-and-pepper noise was 30%, 40%, and 50%, respectively. Therefore, the Lp_HOGS model had a greater advantage when the noise levels increased. The passerby images with different degrees of degradation are shown in Figure 2. The deblurring effects using Lp_LOGS and Lp_HOGS are compared in Figure 3.  
A comparison of Figure 2a,c with Figure 3b,c revealed that the image deblurred by Lp_LOGS had more speckle noise than the one deblurred by Lp_HOGS. The images in the red boxes in Figure 3b,c were enlarged to further visualize the difference between the two and the results are displayed in Figure 3e,f, respectively. The right half was a largely smooth area in Figure 3e,f. Figure 3f had less salt-and-pepper noise compared with Figure 3e and its visual effect was closer to that of the original image. The left half was mostly the edge area, therefore it was difficult to see the denoising
# Research on a Time Series Data Prediction Model Based on Causal Feature Weight Adjustment
## 3 LWA-LSTM Method
### LSTM Algorithm  
Due to the good performance of LSTM in time series data prediction, our approach selects the LSTM algorithm for stock price prediction.  
The specific structure of the LSTM unit is as follows:  
\[f_{t}=\mathit{sigm}\Big{(}w_{fx}x_{t}+w_{th}h_{t-1}+b_{f}\Big{)} \tag{3}\]  
\[i_{t}=\mathit{sigm}\big{(}w_{ix}x_{t}+w_{th}h_{t-1}+b_{i}\big{)} \tag{4}\]  
\[g_{t}=\mathit{tanh}\Big{(}w_{gx}x_{t}+w_{gl}h_{t-1}+b_{g}\Big{)} \tag{5}\]  
\[c_{t}=f_{t}\times c_{t-1}+i_{t}\times g_{t} \tag{6}\]  
\[o_{t}=\mathit{sigm}\big{(}w_{ox}x_{t}+w_{ol}h_{t-1}+b_{o}\big{)} \tag{7}\]  
Among them, \(f_{t}\) stands for the door of forgetting, which determines how much information from the upper layer will be recorded. \(i_{t}\) represents an input gate that determines how much input information will be used. \(g_{t}\) represents a source of alternative information, ready to update new cell status \(c_{t}\). The final output \(h_{t}\) is determined by the current cell state \(c_{t}\) and the intermediate output \(o_{t}\) and entered into the LSTM unit at the next moment. LSTM realizes the long-term transmission of information by building input, forget, and output gates, ensuring that the previous information can always participate in network training.
## 2 Related Works
It can be seen that the architecture based on transistor and operational amplifier show a high performance on low power consumption and high sensitivity, respectively. Based on the SoA, the amplifiers with OAs and transistors are used to reach a sensitivity of more than \(-50\,\mathrm{dBm}\) within a power consumption lower than \(10\,\mathrm{\SIUnitSymbolMicro W}\). Compared to other works based on LF amplifier approach, a higher sensitivity of \(-62\,\mathrm{dBm}\) is reached with the frequency range \(868\,\mathrm{MHz}\). For that, an analytically and experimental analysis and comparison between both architectures in terms of simple hardware design, low power requirement, and high data rate is proposed. Furthermore, to determine reliability, the relationship between sensitivity and number of WuP \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Reference** & [25] & [27] & [29] & [30] & [31] & [32] & [33] & **This Work** \\ \hline Frequency (MHz) & \(868\) & \(868\) & \(868\) & \(868\) & \(868\) & \(433\) & \(433\) & \(868\) \\ Sensitivity (dBm) & \(-53\) & \(-51\) & \(-71\) & \(-90\) & \(-70\) & \(-63\) & \(-63\) & \(-62\) \\ Voltage amplification & none & VM & LNA & LNA & OA & BJT & BJT & OA and BJT \\ Listening mode & AO 1 & AO 2 & DC 2 & DC & AO & AO & AO & AO \\ Data rate (kbit/s) & 2.7 & 1.0 & 250 & 128 & 0.04 & 1.0 & 1.0 & 1.2 \\ Current requirement & 148 & 400 & 165 & 803 & 10,000 & 400 & 400 & 345 \\ transmitter 3 (\(\mathrm{\SIUnitSymbolMicro A}\)s) & & & & & & & & \\ \hline \hline \end{tabular}  
* 1 Always on. 2 Duty-cycle. 3 Estimate for 16-bit address and 25 mA supply current.  
\end{table} 
Table 1: Comparison of data rate and wake-up packets. Their analysis will be within the proposed application, and an indoor setup is built to test the performance of both architectures, which may be of interest for building a wireless sensor network across different rooms and floors. Since the implementation of LF-amplifiers in WuRx circuits represents a very interesting compromise between sensitivity, data rate, latency, and low power consumption, further investigations are required in order to find out the best operating mode.