esa-sceva/satcom-chunk-collection huggingface dataset:
# Quantum Key Distribution Networks: Challenges and Future Research Issues in Security
## 1 Introduction
In addition, for the security issue of QKD networks, [44; 45] proposed feasible resolutions for avoiding the assumption that the quantum nodes must be trusted and [46] discussed how classical end users/applications can access session keys securely from QKD networks. In addition, [47] proposed an architecture of a QKD network, a quantum access network, which allows many end users/applications (up to 64 users/applications) to simultaneously distribute the security keys with a central quantum node using fiber channels. Then, [48] extended the quantum access network to the n:n framework, that is, n users could distribute security keys with n central quantum nodes simultaneously. Although these studies discussed above obtained remarkable results within the key generating rate, communication distance, architecture of the QKD network, and routing algorithm, there are still some challenges that need to be overcome in the field of security. Therefore, this study aims to summarize the developmental trends and results of the QKD network first. Then, we highlight the challenges that need to be studied further to perfect QKD networks. For the proposed challenges, we have also provided some feasible solutions and strategies to allow researchers to devise complete solutions. The rest of this paper is organized as follows: Section 2 reviews the background of the QKD network, and Section 3 summarizes the key results in existing QKD networks. For security issues in QKD networks, we highlight the three challenges and future research issues and provide some feasible resolution strategies in Section 4. Finally, a brief conclusion is provided.
## 4 Experimental Results
### Implementation
#### 4.2.2 Computational Complexity of the Method  
The size of the 3D image \(I\) is taken to be approximately \(|I|\approx 200\times 150\times 60\approx 2\times 10^{6}\). The size of the statistics using the dynamic ranges is \(\left(\eta_{i}^{max}\right)^{2}=500\times 500=0.25\times 10^{6}\). The order of the cost of the main steps of the method per iteration \(t\) is as follows:  
* Computation of the co-occurrence and the joint co-occurrence statistics: \(3|I|\left(\frac{\rho}{\Delta\rho}\right)^{2}\approx 6\times 10^{6}\times \left(\frac{\rho}{\Delta\rho}\right)^{2}\).
* Deconvolution of the statistics: \(3\left(\eta_{i}^{max}\right)^{2}\left(\sigma_{\eta}\right)^{2}=0.75\times 10^{6} \times\left(\sigma_{\eta}\right)^{2}\).
* Back-projection to the image: \(3|I|\left(\frac{\rho}{\Delta\rho}\right)^{2}\approx 6\times 10^{6}\times \left(\frac{\rho}{\Delta\rho}\right)^{2}\).
* Gaussian smoothing of spatial nonuniformity: \(2|I|\left(\sigma_{s,cum}\right)^{2}\approx 4\times 10^{6}\times\left( \sigma_{s,cum}\right)^{2}\).
* MDL smoothing of spatial nonuniformity: \(2|I|3^{3}K_{cum}\approx 108\times 10^{6}\times K_{cum}\), where \(3^{3}\) is the connectedness in MDL smoothing.
* Multiplication of incremental spatial nonuniformity with cumulative spatial nonuniformity: \(|I|\approx 2\times 10^{6}\).  
The size of the 3D image, \(|I|\), is larger than the size of the 2D co-occurrence statistics, \(\left(\eta_{i}^{max}\right)^{2}\). Therefore, the image domain operations for the spatial nonuniformity dominate. The costs of computing the co-occurrence statistics and of back-projecting them to the image are almost the same. The most expensive image-based operation is the cost of MDL smoothing of the nonuniformity. Its cost is greater for larger values of the number of iterations \(K_{cum}\) compared to the number of the co-occurrence sampling pixels, \(\left(\frac{\rho}{\Delta\rho}\right)^{2}\).
## 6 Conclusions  
In order to ensure that open-type TBM can achieve rapid excavation in the water-rich and poorly cemented sandstone strata, this paper utilized CT scanning to analyze the micro characteristics of the sandstone in the Luohe Formation. Based on these analysis results, this paper conducted numerical simulations to compare the effectiveness of different support schemes in controlling the surrounding rock, and the following conclusions are reached:  
1. The CT scan results indicate that in the two sets of samples from the Luohe Formation sandstone, the volume percentages of pores with a diameter of \(\geq\)34 \(\upmu\)m are 2.3% and 1.5%, respectively, and the volume percentages of pores with an equivalent diameter greater than 200 \(\upmu\)m are the largest, at 61.4% and 36.0%, respectively. This means that there is a relatively high porosity, and the pores are predominantly larger in size. This is macroscopically manifested as strong permeability in the surrounding rock, making it susceptible to softening and fragmentation.
2. The numerical simulation results show that replacing the original \"bolt + mesh\" support scheme with a \"bolt + cable + mesh + steel belt\" support scheme can effective control surrounding rock deformation, and the top maximum displacement from 94.7 mm reduced to 70 mm, and the radial stress at the boundary of the surrounding rock increased from 0 to 3 MPa, providing significant restraint to the surrounding rock.  
Figure 19: Comparison of support effect of two support schemes. (**a**) Bolt + mesh. (**b**) Anchor + cable + mesh + steel belt.  
3. Field applications have shown that after adopting the new support scheme, the maximum deformation of the surrounding rock has decreased from 50.3 cm to 28.5 cm, a reduction of 43.3%. The water inflow rate has decreased from 308 m\({}^{3}\)/d to 98 m\({}^{3}\)/d, a reduction of 68.2%. The TBM excavation speed has increased from 10 m/d to 17 m/d, an improvement of 70%. This significantly enhances construction efficiency and provides assurance for early production commencement.  
Theoretical analysis and CT scanning, X.K.; numerical simulation, K.Z.; on-site sampling, A.L. and Y.K.; review the full paper, X.X. and B.Z. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the National Nature Science Funds of China under grant 52038008, and 52378408; and the Science and Technology Project of China Railway 15 th Bureau Group Co., Ltd. (2021A1, 2021C61). The authors gratefully acknowledge their financial support.  
Not applicable.  
The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.
## 2 Results and Discussion
### Analysis of Cinnamon Volatiles by SPME/GC-MS  
SPME/GC-MS is well suited for the analysis of VOCs of aromatic plants and spices even at trace levels [22; 23]. Hence, SPME/GC-MS was used in this study to discriminate between various authenticated cinnamon species of different origins along with commercial products targeting their aroma profile (Table 1).  
The SPME StableFlex (DVB/CAR/PDMS 50/30 \(\upmu\)m) fiber was employed as it provided higher sensitivity in volatiles collection compared to the polydimethylsiloxane (PDMS) fiber and is more suitable for VOCs analysis based on our previous report [23]. Figure 1 represents the total ion chromatograms (TIC) of the four authenticated cinnamon samples, i.e., CA, CI, CT, and CV, with the labeling of the major peaks listed in Table S1.  
Results showed that a total of 126 peaks were detected belonging to different chemical classes, i.e., acids (6 peaks), alcohols (24), aldehydes / ethers (21), aliphatic hydrocarbons (2), aromatic hydrocarbons (7), esters (22), ketones (6), lactones (3), oxides (3), phenols (5), pyrans/furans (4), and sesquiterpene hydrocarbons (23). Authenticated samples, including CA, showed the highest number of peaks with 122 volatiles, while CMV showed the lowest with 107 peaks. In comparison with previous studies, the current approach aided in detecting more, where [PERSON] et al. reported 67 VOCs in the essential oil of _C. verum_ [PERSON] via SPME/GC-MS [24], only 23 compounds in _C. verum_ [PERSON] essential oil with GC-MS [14]. Likewise, only 47 compounds were identified in the n-butane extracts of different _Cinnamomum_ species by GC/MS [25]. An increase in identification score may be attributed to data processing using the AMDIS program for peak deconvolution, aiding in identifying more peaks. Regarding commercial products, CP-1 showed the highest number at a total of 114 versus CP-3, with 98 peaks for commercial products.  
The volatile class percentile levels in all investigated cinnamon products are depicted in Figure 2. Additionally, the major chemical classes, including the most abundant VOCs, identified using SPME/GC-MS analysis and contributed mainly to cinnamon's unique aroma, will be discussed in the next subsections (Sections 2.1.1-2.1.6).  
Figure 1: Total ion chromatograms (TIC) of investigated authenticated cinnamon samples (_Cinnamomum_ sp.). The major peaks are labeled based on the tentatively identified volatiles listed in Table SI.
# Measurement of Bridge Vibration by UAVs Combined with CNN and KLT Optical-Flow Method
###### Abstract
The two-layer feedforward neural network (FNN) was used to learn the characteristic relationship between the reference background and target points from the video with no structural motion [29]. The target-point coordinates can be estimated through the reference background when the structure is vibrating, which can be used to determine the homography transformation matrix of each frame image, so as to obtain the real coordinates of the target points. A measurement method of bridge vibration by UAVs based on the KLT optical-flow method and a CNN is proposed in this paper. In this method, the KLT optical-flow method is used to accurately track the target points, and the multilayer CNN is used to effectively learn the characteristic relationship between the reference points and the target points to eliminate the false displacement of the UAV, so as to obtain the real displacement time-history curves of the structure, and the natural frequency of the model is extracted by OMA [30; 31]. Finally, the measurement results of DIC and fixed camera are used as references to validate the reliability of the method proposed by this paper.
## 1 Introduction
[PERSON] [21] developed an integrated CFD model able to consider the relationship between indoor and outdoor environments, lighting, occupancy, and HVAC systems. The list of scientific papers that use CFD to simulate the thermo-hygrometric conditions inside ancient buildings is extensive [22; 23; 24; 25; 26; 27]. In this framework, this study is oriented to a very specific topic, namely the investigation of the effect of an electrical transformer enclosure placed inside an ancient Roman building. This work paves the way for analyzing the variation in the ancient building's indoor environment due to the installation of an electric transformer enclosure. The decision to use a historical building for this study could be surprising. But due to the Archaeological Park of the Colosseum, at the center of Rome, near the Roman Forum of Trajan, there are no other places wherein the electrical transformer enclosure could be installed. A new building could alter the sight of the ancient ruins, altering the park's appearance. At the same time, the underground is full of buried ruins, making it impossible to create a new underground environment to host the transformer enclosure. Therefore, it could only be placed inside an existing Roman building. To guarantee the indoor hygrothermal conditions of the ancient Roman building (named \"Museeto\") due to the presence of an electrical transfer enclosure, different analyses were carried out. Firstly, an experimental campaign was carried out to collect environmental data using outdoor and indoor sensors. The campaign was carried out during the warmest months, from July to September (19 July 2020-17 September 2020), to investigate the worst operating conditions and the maximum overheating that could be achieved during the year. Then, the collected data were used to validate a CFD model and two different layouts for the electrical transformer enclosure were simulated. They differ by the presence of an enclosure layer between the electric transformer system and the indoor environment. Moreover, two different flow rates, 2200 m\({}^{3}\)/h and 1100 m\({}^{3}\)/h, were used to assess the internal temperature and humidity over the year. The two flow rates were chosen by the company in charge of the cabin's design for the Archaeological Park of the Colosseum. This paper starts with the identification of the ancient building named \"Museeto\". This section contains all the information related to the building itself and the measurement campaign. Then, the CFD model set-up is presented, as well as the validation of the model based on the measurement campaign data; two different transformer enclosure layouts are introduced and simulated. One has the power transformer placed in an open configuration, and the other has the power transformer placed within a confined environment. Finally, the results are presented, and the main relevant findings are discussed, with a comparative analysis of the advantages and disadvantages related to the two configurations.
## 3 Setup Characterization Used in a VPI Simulator
ESA: Electrical Spectrum Analyzer, Att: Attenuator, OF: Optical Filter, LNA: Low-Noise Amplifier, BER: Bit Error Rate, QAM: Quadrature Amplitude Modulation, PD: Photodiode, and OPC: Optical Pulse Clock. signal to be mixed at the outer gate of the SOA-MZI because of the SOA-MZI dynamic behavior. As a result, the harmonics of the sampling OPC signal play the main role in improving the mixed signal because they are improved considerably at the top frequencies due to the modulation schema. This also leads to ameliorating the performance of this optical transmission system. Up-conversion simulations of the signal to be mixed that loads QPSK data are assessed at the data rate of 5 Gbit/s. Two subcarriers are entered into the SOAs electrodes for differential modulation. The quality of the mixing is evaluated through the error vector magnitude (EVM) [27] calculated in order to estimate the quality of the signal to be mixed. The BER_El-M-QAM module is employed to compute the bit error rate (BER) of the signal to be mixed. Hence, EVM values are found from the BER [28]. The EVM boundary of the QPSK data is 17.5% [29]. As exhibited in Figure 4, the EVM of the signal to be mixed enlarges with its frequency at 5 Gbit/s. The EVM value upgrades at the top frequencies compared to all-optical  
Figure 4: Conversion gain and EVM of the signal to be mixed that loads QPSK at \(nf_{s}+f_{IF}\). Figure 3: Electrical spectrum that represents the power in dBm of the signal to be mixed at the outer port of SOA–MZI versus the mixing frequencies \(nf_{s}\pm f_{IF}\) in GHz for the modulation of differential mode. sampling SOA-MZI [11; 12; 13; 14; 15; 16] and electro-optical RSOA [23]. It reaches 14% at 195.5 GHz, which is beneath the EVM boundary. The EVM of the signal to be mixed at the top frequency downgrades more than the one at the lowest one because of \(H_{n}\) of the OPC signal. Following the higher position of harmonics play the essential function of enhancing the sampled signal because of the electro-optical differential modulation principle.
## 3 Results
### ABTS Radical Scavenging Activity  
The effects of the enzyme used on ABTS radical scavenging activity of the porcine liver protein hydrolysates are shown in Table 2. All samples were strongly influenced by the type of membrane and the enzyme used (\(P<0.001\)). The porcine hydrolysates obtained in the hydrolysis with alcalase provided higher activity than those obtained with the other two enzymes at both hydrolysis times studied. These values even tripled the maximum value obtained for the other enzymes (936 and 1068 mg AA/100 g vs. 335 and 416 mg AA/100 g, and 392 and 335 mg AA/100 g for alcalase, papain and bromelain extracts obtained from a hydrolysis time of 4 h and 8 h, respectively).  
The ultrafiltration step significantly (\(P<0.05\)) affected the activity of the samples analyzed. The behavior was different depending on the enzyme and the pore size used. For papain the best choice of membrane was 30 kDa (416, 368, and 352 mg AA/100 g resulted from hydrolysis time of 8 h and with membranes measuring 30 kDa, 10 kDa, and 5 kDa, respectively) and for bromelain the best choice of membrane was 10 kDa (392, 346, and 281 mg AA/100 g resulted from hydrolysis time of 4 h and with membranes measuring 10 kDa, 5 kDa, and 30 kDa, respectively), since the antioxidant properties obtained were greater. For alcalase, at 4 h the 30 kDa membrane was the best option, while at 8 h the best option was 10 kDa (936 and 1068 mg AA/100 g, respectively).  
As can be seen in the results obtained, time also had an important impact on the ABTS activity. Papain and alcalase showed higher activities when the hydrolysis time increased, while 4 h hydrolyzing period was enough to hydrolyze porcine livers with bromelain (392 vs. 335 mg AA/100 g for 4 h and 8 h processes, respectively).
# An Efficient Information Retrieval System Using Evolutionary Algorithms
## 5 Discussions and Analysis  
Through several experiments, a set of evaluation measurements and comparisons with other related works were made of the following results:  
(a) The proposed ADIM reduced the time of document indexing and reduced the memory space by using simple processes; these processes are removing special words and delimiter sentences and stopping word removal.  
(b) The suitable number of queries is 50 queries to test the proposed system in terms of performance and accuracy. In addition, queries contain a different number of related documents (small, medium, and large).  
(c) The suitable population size for the MGA is 75 to retrieve all the possible related documents to the user query or retrieved results close to the number of these relevant documents.  
(d) CA applied the adaptation process when the result of accuracy is not sufficient, which ensures the best accuracy and high-performance system.  
(e) A set of evaluation measurements and comparison with other related works made the results; the average value of recall is 98.5%, precision is 100%, and the response time is 0.46.7 milliseconds.  
(f) GA operators work with a proposed FF, random selection mechanism, elitism mechanism to parent selection, single-point crossover, and ordinary mutation. The optimal solution of the proposed system is achieved with a population size of 75 at iteration 15.  
(g) displaying the most relevant document to the user query requires no ranking step display because to find the optimal solution, the documents are ordered according to their fitness value; this process saves time in the ranking step and guarantees the most relevant document will be displayed first.  
Figure 12 demonstrates the concise and concrete results when executing the system along with the visualization method.  
Figure 12: The general execution of ADIM-MGA with integrated CA.  
\begin{table}
\begin{tabular}{l c c c} \hline \hline
**Item** & **Proposed** & **Ref. [20]** & **Traditional** \\ \hline Documents indexing method & ADIM & Enhance inverted index & Inverted index \\ Memory space for the doc. indexing & 18.8 MB & 100 MB & 895.186 MB \\ Average Recall & 98.5\% & 84\% & N/A \\ Average of Precision & 100\% & 86\% & N/A \\ Response time in milliseconds & 00.46.74.78 ms & N/A & Measured by minutes \\ Displaying the most relevant document & based on the fitness function & first 10 ranked documents & ranking method \\ Optimal solution convergence & 15 iterations & 22 iterations & N/A \\ Population size & 75 & 125 & N/A \\ \hline \hline \end{tabular}
\end{table}
Table 11: Comparison with traditional and other related work.
## 3 Results
### PCR Detection of E. coli Genomic DNA  
Second, we wondered whether high NaCl concentration inhibits DNA polymerase and, in that way, decreases the sensitivity of PCR detection of bacteria. For this, genomic DNA were extracted from bacterial cells cultivated in four above media (LB, LB + NaCl; PB, and PB + NaCl) and tested for the efficiency of classical PCR. Previously validated primers that target consensus sequence of the orphan gene _yaiO_ of _E. coli_ yielding 115 bp PCR product [8] were used for PCR amplification. Figure 2 points out that the expected amplicon of 115 bp was detected with similar sensitivity using DNA from bacteria cultivated in pure bacterial media and in corresponding media supplemented with 0.4 M NaCl. This indicates that classical PCR technique can be successfully applied for _E. coli_ detection in seawater.  
Figure 1: (**a**) Survival curves of _E. coli_ at 10\({}^{8}\) CFU/mL suspended in different solutions. (**b**) Phase contrast transmission micrographs of _E. coli_ cells incubated for 30 h in different media. Scale bar, 10 \(\upmu\)m stains for all images.  
Figure 2: (**a**) PCR sensitivity with _yaiO_ primer set obtained with different concentrations of DNA extracted from _E. coli_ cells cultivated in LB (upper panel) and LB + 0.4 mM NaCl (lower panel). Line 1: 200 ng/uL; line 2: 20 ng/uL; line 3: 2 ng/uL; line 4: 20 pg/uL; line 5: 2 pg/uL; line 6: 200 g/uL; line 7: 20 g/uL; line 8: 2 f/g/uL; line 10: no template control. (**b**) PCR sensitivity with _yaiO_ primer set obtained with different concentrations of DNA extracted from _E. coli_ cells cultivated in Bacto Peptom medium, BP, (upper panel) and BP + 0.4 mM NaCl (lower panel). Line 1: 200 ng/uL; line 2: 20 ng/uL; line 3: 2 ng/uL; line 4: 200 pg/uL; line 5: 20 pg/uL; line 6: 2 pg/uL; line 7: 200 g/uL; line 8: 20 f/g/uL; line 9: 2 f/g/uL; line 10: no template control. DNA ladder (1 bp +) was used in all experiments.  
However, although very robust, sensitive and specific classical PCR demands previously extracted and purified genomic DNA. Thus, we also tested whether direct PCR (without performing DNA isolation and purification steps) can be used to evidence _E. coli_ in highly salted media.
## 5 Experimental Verification and Results
### Experimental Verification at Rated Speed  
When the speed is set to 1000 r/min, the observed speed response of the two regulators under no-load and 2\(N\)\(n\)\(n\) load are presented in Figures 32 and 33.  
Figure 31: Experimental test platform for the proposed algorithm  
Figure 30: The structure of the experimental platform.  
From Figures 32 and 33, it is worth noting that the adjustment time of the proposed VPDPI regulator is clearly shorter, while almost no overshoot. However, the observed speed overshoot under the traditional PI regulator is about 75 r/min. Meanwhile, the speed pulsation of the proposed regulator is more smaller under both no-load and load conditions, especially with load condition. In addition, the observation accuracy is more higher than the traditional PI regulator when the system runs stably. Hence, the proposed regulator has outstanding dynamic performance and precision of speed estimation, which proves the validity of the method again.