esa-sceva/satcom-chunk-collection huggingface dataset:
Therefore, HCLPs based on PS and their amine group-modified forms have recently been investigated as efficient and low-cost CO\({}_{2}\) adsorbents [26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38]. For example, [PERSON] et al. [27; 28] synthesized several types of HCLPs from waste expanded PS using different cross-linking agents; the best achieved CO\({}_{2}\) absorption was 2.5 mmol g\({}^{-1}\) and CO\({}_{2}\)/N\({}_{2}\) separation efficiency of 38 at 273 K. The cross-linking of aromatic polymers was found to improve the textural properties of the prepared materials and enhance their CO\({}_{2}\) adsorption capacity [33; 34; 35; 28]. [PERSON] et al. [36] prepared HCPs of different porosities from commercial PS; the porous structure of the HCLPs was tuned by varying the ratio of PS and cross-linker. The maximal CO\({}_{2}\) adsorption capacity was 1.12 mmol g\({}^{-1}\) at 298 K and a pressure of 1 atm. The amine functionalization of PS adsorbents was studied by [PERSON] et al. [32]. The influence of the length of the polyamines used in modifying the porous polymer adsorbents on their structure and selective CO\({}_{2}\) adsorption was studied. After amination, the prepared materials showed increased CO\({}_{2}\) adsorption capacities (the values were similar for all used polyamines, up to 1.86 mmol g\({}^{-1}\) at 273 K and 1 bar) and higher CO\({}_{2}\)/N\({}_{2}\) selectivity; however, the surface area of the modified polymers was considerably reduced. Similarly, [PERSON] et al. [37] investigated the CO\({}_{2}\) uptake and CO\({}_{2}\)/N\({}_{2}\) selectivity of PS-based adsorbents by modifying chloromethylated PS with \(N\)-heterocyclic compounds. Conversely, [PERSON] et al. [38] found only a moderate CO\({}_{2}\) uptake of 1.05 mmol g\({}^{-1}\) at 273 K for amine-tethered PS adsorbents synthesized from waste expanded PS. This study focuses on the synthesis of hyper-crosslinked vinylbenzyl chloride (VBC)-divinylbenzene (DVB) microporous material and its functionalization using the amino group-containing substances, simple amines, and larger dendrimer molecules to investigate their potential for application in CO\({}_{2}\) capture and gas separation. The main objective of the work is the preparation of a series of hyper-crosslinked polymers, the characterization of their physicochemical properties and the investigation of the CO\({}_{2}\) adsorption performance and selectivity of materials over other gases and to analyze the effect of modification by amino groups containing substances of different sizes.
## 2 Materials and Methods
### Comet Assay  
The alkaline (pH 12.1) Comet assay was performed to investigate the presence of DNA strand breaks in zebrafish blood cells at different exposure conditions, as previously reported [28]. A total of 15 \(\upmu\)L of blood cell suspension containing 10\({}^{6}\) cells/mL were mixed with 65 \(\upmu\)L of low melting point agarose (0.7%) and inserted into layers of normal melting agarose (1%) on slides. Slides were prepared in triplicate for each sample. These were incubated in lysis solution (NaCl 2.5 M, Na\({}_{2}\)EDTA 0.1 M, tris-base 0.4 M, triton-X100 1%, dimethyl sulfoxide-DMSO, 10%, pH 10), followed by incubation in alkaline solution (NaOH 10 N, ethylenediaminenetetraacetic acid--EDTA 200 mM, pH 12.1). Slides were then exposed to electrophoresis (25 V, 300 mA, 0.7 V/cm) for 20 min to allow the migration of DNA, followed by fixation in cold methanol and staining with ethidium bromide 1\(\times\). A total of 50 cells per slide was analyzed under fluorescence microscope (Nikon Eclipse E-600, 60\(\times\) magnification, BP 515-560 nm filter, LP 580 nm filter). The images were captured and analyzed by OpenComet software [29]. DNA strand breaks were assessed by analyzing damaged DNA present in the comet tail (% tail DNA).
# CASVM: An Efficient Deep Learning Image Classification Method Combined with SVM
## 4 Experimental Results and Analysis
### Parameter Impact and Selection
#### 4.1.5 Impact and Selection of Attentional Mechanisms  
The attention mechanism functions to improve image feature extraction. Under the same structure conditions, a network with an attention mechanism can better extract image features. Figure 6 shows the effect of the attention mechanism on training in a network model with different loss functions and two classifiers.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Optimizer**} & \multirow{2}{*}{**Model**} & \multicolumn{4}{c}{**Learning Rate (Accuracy)**} & \multicolumn{4}{c}{**Learning Rate (Loss)**} \\ \cline{3-8}  & & **0.001** & **0.0001** & **0.0001** & **0.001** & **0.0001** & **0.00001** \\ \hline \multirow{8}{*}{SGDOptimize} & CNN1 & 0.26 & 0.30 & 0.32 & 0.35 & 0.34 & 0.33 \\  & AlexNet & 0.38 & 0.42 & 0.43 & 0.32 & 0.30 & 0.29 \\ \cline{1-1}  & CNN2 & 0.51 & 0.54 & 0.55 & 0.27 & 0.25 & 0.25 \\ \cline{1-1}  & ResNet18 (32 \(\times\) 32) & 0.34 & 0.46 & 0.50 & 0.32 & 0.28 & 0.28 \\ \cline{1-1}  & ResNet18 (224 \(\times\) 224) & 0.36 & 0.39 & 0.41 & 0.32 & 0.31 & 0.30 \\ \hline \multirow{8}{*}{RMSPropOptimize} & CNN1 & 0.68 & 0.74 & 0.76 & 0.20 & 0.17 & 0.17 \\  & AlexNet & 0.50 & 0.60 & 0.59 & 0.26 & 0.22 & 0.24 \\ \cline{1-1}  & CNN2 & 0.63 & 0.70 & 0.76 & 0.22 & 0.18 & 0.21 \\ \cline{1-1}  & ResNet18 (32 \(\times\) 32) & 0.72 & 0.78 & 0.81 & 0.17 & 0.18 & 0.20 \\ \cline{1-1}  & ResNet18 (224 \(\times\) 224) & 0.61 & 0.81 & 0.81 & 0.22 & 0.13 & 0.14 \\ \hline \multirow{8}{*}{AdamOptimizer} & CNN1 & 0.74 & 0.77 & 0.80 & 0.17 & 0.15 & 0.15 \\ \cline{1-1}  & AlexNet & 0.66 & 0.69 & 0.73 & 0.19 & 0.18 & 0.16 \\ \cline{1-1}  & CNN2 & 0.64 & 0.73 & 0.77 & 0.20 & 0.17 & 0.15 \\ \cline{1-1}  & ResNet18 (32 \(\times\) 32) & 0.80 & 0.86 & 0.86 & 0.15 & 0.13 & 0.15 \\ \cline{1-1}  & ResNet18 (224 \(\times\) 224) & 0.62 & 0.83 & 0.89 & 0.21 & 0.12 & 0.09 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Effect of different optimizers on training.  
Figure 5: Classification accuracy of test set with training set learning rates of 0.01, 0.001, and 0.0001.  
In Figure 6, Animal10 is the dataset for training and testing, and AlexNet is the network model. The network uses hinge and cross-entropy loss functions. As can be seen from the figure, the accuracy of the model improves with the addition of CA, which is denoted by the green line; the reverse is denoted by the red line. With consistent loss functions and CA added, CASVM has higher classification accuracy than softmax. Whether using SVM or softmax classification, accuracy improves with the addition of CA. Hence, attention usually greatly improves the accuracy of image classification.
# DSP-Based 40 GB/s Lane Rate Next-Generation Access Networks +
## 3 Simulation Results
### DSP Complexity
For MLSE, first, for the optical or electrical Duobinary scheme, the memory length can be further reduced to 1, leading to halved multiplication and sum operations at the cost of the degradation of the power budget performance to some extent for \(>\)10 km SMF cases. The MLSE complexity for all modulation schemes can further be reduced by calculating the metrics using histogram and averaging, whose result can replace the \(\sum_{l=0}^{L}c_{l}\cdot x[k-l]\) term in Equation (2). Since the histogram and averaging can be performed at the beginning of the communication, and it rarely needs further calculations, as the optical channel is relatively stable, it can be assumed that such an operation does not contribute to MLSE complexity. As a result, it gives almost no multiplications, and also reduces the sum operation count for MLSE. This indicates the superior complexity performance of MLSE and its feasibility for access networks.
###### Abstract  
This paper presents a novel magneto-optical isolator based on an ultra-wideband and high efficiency photonic crystals (PCs) waveguide and gyromagnetic ferrites. The three-dimensional numerical simulation finds that the photonic crystals waveguide's (PCW) transmission efficiency rises with its height and width. The corresponding experiments are performed by using a triangular lattice Al\({}_{2}\)O\({}_{3}\) dielectric posts array in 5G millimeter wave band. The measured transmission efficiency is up to 90.78% for the optimal PCs waveguide structure, which has ultra-wide operating bandwidth from 23.45 to 31.25 GHz. The magneto-optical isolator is designed by inserting two rectangular gyromagnetic ferrites into the PCs waveguide. Due to the contrast between the effective permeability of the left and right circular polarization waves passing through the magnetized ferrite sheets, the ferromagnetic resonance absorption of the forward and reverse waves is different. By using finite element method, the isolation is optimized to be 49.49 dB for the isolator and its relative bandwidth reaches 8.85%. The high isolation, broadband, and easy integration indicate that our designed magneto-optical isolator has significant advantage in 5G communication systems.  
Keywords:5G communication; wideband; magneto-photonic isolator; photonic band gap; photonic crystals waveguides +
Footnote †: journal: Physics Letters B
# Characterization of Invar Syntactic Foams Obtained by Spark Plasma Sintering
## 1 Introduction
[10] studied the effect of the Ni and Fe particle size on the compressive and tensile strength of syntactic Invar foams with 5% glass microspheres, obtained by metal injection molding (MIM). The influence of the deformation speed of extruded and sintered Invar foams with 5% and 10% glass microspheres on mechanical behavior was also investigated by [PERSON] et al. [11]. In the literature, there are relatively few studies regarding the consolidation of syntactic foams with Invar matrices by spark plasma sintering; therefore, this study aims to complete the gap in knowledge in this field. The aim of this work is to obtain syntactic foams of Invar with NiCrSiB superalloy hollow spherical particles through specific powder metallurgy techniques, and to study the influence of the addition of NiCrSiB on the thermal expansion coefficient of Invar. Superalloy powders from the Ni-Cr-Si-B(\(\pm\)C) system, obtained by gas atomization, are used as deposited layers, especially to increase the corrosion and oxidation resistance at high temperatures [21,22]. The CTE value of the NiCrSiB superalloy foams, obtained by sintering of the hollow spherical particles (similar to those used in this research), is approximately 18.2 \(\times\) 10\({}^{-6}\)\({}^{\circ}\)C\({}^{-1}\) in the temperature range of 25-400 \({}^{\circ}\)C [20]. The novelty of the research presented in this paper is in the synthesis of a syntactic foam comprised of a metal matrix (Invar), with the pore-forming agent being NiCrSiB superalloy hollow spherical particles (also a metal). This metallic foam would combine the characteristic property of Invar (low CTE) with the high temperature stability of the superalloy, while also having a low density.
# An Efficient Multistage Approach for Blind Source Separation of Noisy Convolutive Speech Mixture
## 6 Conclusions and Future Work  
This paper proposes an efficient hybrid multistage approach for blind source separation (BSS) of noisy convolutive speech mixtures. In the BSS stage, a hybrid source prior model consisting of multivariate super-Gaussian and generalized Gaussian distribution models of the source signals is used in the observed noisy reverberant mixture. The weights are assigned between the source priors following the energy of the observed convolutive mixture. In the de-noising stage, the noise is suppressed by the MMSE filtering technique using two different proposed models. In the first model, the BSS module is followed by the de-noising stage. In the second model, the de-noising module is followed by the BSS stage. Both proposed models are compared with the literature, where the results clearly show the performance improvement of the proposed schemes. Furthermore, it was observed from the results that the proposed model with a BSS module followed by de-noising stage shows a significant gain in comparison with the model with first de-noising followed by the BSS stage.  
In future work, we will perform experimental measurements in a real-time setup and compare the simulation and practical results both in terms of SNR, energy distribution, and error performance.  
The work was developed as a collaboration among all authors. [PERSON], [PERSON], and [PERSON] designed the study and system development. [PERSON] and [PERSON] directed the research and collaborated in discussion on the proposed system model. The manuscript was mainly drafted by [PERSON], [PERSON], [PERSON] and [PERSON] and was revised and corrected by all co-authors. All authors have read and approved the final manuscript.  
This research received no external funding.  
Not applicable.  
Figure 10: (**a**) Comparison of the two proposed models for \(\hat{S}_{1}\) with variable RT (msec); (**b**) Comparison of the two proposed models for \(\hat{S}_{2}\) with variable RT (msec).  
Data Availability Statement: Publicly available datasets were analyzed in this study. This data can be found here: [[https://github.com/philipperemy/timit](https://github.com/philipperemy/timit)]([https://github.com/philipperemy/timit](https://github.com/philipperemy/timit)) (accessed on 20 June 2021).
# Reversible Data Hiding in Encrypted Images Based on the Mixed Multi-Bit Layer Embedding Strategy
## 4 Experimental Results and Discussion
### Image Quality Analysis
Figure 8: Performance between decryption quality and embedding rate compared with schemes Zhang [14], Zhang [17], Xu [22], Ma [23], Qin [24] and Yi [30]. (**a**) Lena, (**b**) Airplane, (**c**) Peppers, and (**d**) Baboon. However, the data can be extracted accurately in [17]. The common point of [14; 15; 16; 17] is that the scheme can realize the lossless recovery of the cover image only if the block size satisfies certain embedding conditions. Compared with the above schemes, the data-error-free extraction and the cover image lossless recovery can be guaranteed in the rest schemes and the proposed scheme. In addition, in the works [14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39] and the proposed scheme, secret data are embedded in a single encrypted cover image. In the works [40; 41; 42], secret data are embedded in multiple shared and encrypted images. In contrast, the works using secret sharing technology belong to the VRAE framework and have great potential in terms of embedding capacity. However, the amount of data during transmission increased several times, and the receiver needs multiple transmission images to recover the original cover image. In the proposed scheme and works [14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39], the focus is more on improving the load capacity while ensuring that the amount of data transmitted remains unchanged and recovering secret data and the cover image through a single transmission image. Therefore, combined with the experimental data in Table 4 and Figure 8, and the above analysis, it can be seen that the proposed scheme is superior in terms of embedding ability, image recovery quality, and separability compared with the related works.
## 2 The Application of Metamaterials
A closer examination of three-dimensional mechanical metamaterials reveals their remarkable potential in acoustic and filter applications. These acoustic metamaterials possess the extraordinary ability to manipulate and govern sound waves, transcending the limitations of conventional materials. Particularly intriguing are metamaterials exhibiting zero or negative refractive indices for sound, opening up new frontiers in acoustic imaging [25; 26] and enabling the precise control of sound at subwavelength scales. The rich tapestry of three-dimensional periodic metamaterials thus promises a fascinating journey into uncharted realms of scientific exploration [27]. Multifunctional metamaterials exhibit multiple and often unusual properties, simultaneously, which cannot be found in naturally occurring materials. These materials are designed to manipulate electromagnetic waves, sound waves, and other types of waves to create desired properties, such as negative refraction, cloaking, and superlensing. Multifunctional MM takes this a step further by combining different types of MM to create materials with multiple functionality. For example, MM with a negative refractive index can be combined with MM, which is designed to absorb electromagnetic waves. Another combination can be energy harvesting material with vibration control parameters [28] or which absorbs and senses possibility [29]. Hierarchical structures with constituents over multiple length scales are found in various natural materials, such as bones, shells, or spider silk. All displays enhanced quasi-static mechanical properties, such as high specific strength, stiffness, and toughness [30]. Introducing the concept of hierarchy in elastic metamaterials leads to periodic structures, capable of generating multiple, highly attenuative, and broadband BGs at multi-scale frequencies, including deep sub-wavelengthregime [31]. Hierarchical bio-inspired metamaterials can provide advantages for dynamic responses as compared to the conventional materials [30]. The diverse array of metamaterial types showcased here (Figure 1) exemplifies the transformative potential they hold in fostering environmental wellbeing and advancing sustainability. Whether it be their unique compositions, carefully chosen materials, or the latest strides in research, metamaterials offer distinct avenues through which positive environmental impacts can be realized (look Table 1). In the realm of sustainable development, these remarkable materials have already demonstrated their prowess in propelling green energy initiatives, promoting biodiversity conservation, and facilitating advanced filtration systems. It is through the judicious application of metamaterial technologies that we can forge a more sustainable future, one where in innovation is harmonized seamlessly with ecological stewardship.
## 4 Proposed Algorithm
### Selection of Mother Wavelet  
Because of ambient and electric noises, measurement signals inherently include a background noise. The electric noise is generally included in the high-frequency band, and interferes with detection of PPI. Such a noise can be removed by a low-pass filter [6]. Since human heart rates are in the range of 40 to 200 per minute [19] and the 99% power of SDPPG is below 10 Hz described in Section 2, a low-pass filter with a cutoff frequency of 20 Hz can remove such a noise.  
After removing background noise from the measured signal, the algorithm determines a reference signal of a single period to select the mother wavelet for wavelet transform. To that end, the SDPPG signal of a few periods is averaged, which is set to a reference signal.  
Since an SDPPG signal is dependent on the subject, by cross-correlation between the reference signal and mother wavelets, the algorithm chooses the mother wavelet that is the most similar to the reference signal among mother wavelets such as Harr, Daubechies, or Symlet.
# Experimental Study of Biogas-Hydrogen Mixtures Combustion in Conventional Natural Gas Systems
## 3 Results and Discussion
### Combustion Behavior  
#### 3.2.1 Combustion Stability  
Fuel composition variability is a strong limitation in biogas combustion. Biogas composition varies depending on the waste characteristics; even if they are the same waste, it can vary depending on the season, humidity, storage, etc. Hydrogen addition also affects fuel variability and can worsen it at high concentrations [47]. Fuel variability has a strong effect on flame speed fluctuation, causing instability in combustion. [PERSON] and [PERSON] demonstrated that a high hydrogen content reduces laminar flame speed variance and has a significant impact on methane reaction [12]. The hydrogen content causes a suppression of carbon dioxide contribution. They revealed a second finding regarding the adiabatic flame temperature, as high hydrogen content reduces the effect of methane and increases the carbon dioxide contribution. Consequently, hydrogen addition in biogas decreases the practical fuel variability and flame fluctuation. However, when methane content exceeds 70% in biogas-hydrogen fuel, a high hydrogen content can promote flame fluctuation. The aim of this study is to propitiate combustion stability in a conventional burner, so the hydrogen content does not surpass 25%.  
During the tests, the burner behavior was observed through the stability electronic control incorporated in the burner. Residential or industrial burners are electronically controlled systems designed to avoid safety hazards. Thus, they are rigid systems, prepared to work in specific operational conditions. Every single change affects the combustion and normally produces ignition failure. Figure 10 represents the stability map registered during the tests. The stability map is divided into three regions, where the red area represents poor combustion, the yellow area represents unstable combustion, and the green area represents stable combustion.  
Figure 9: Exhaust gas stream temperature.  
The ignition testing results coincide with other research works carried out with laboratory devices [13; 18; 34]. The stability map reveals that pure biogas combustion is unstable in every case, and when the CO\({}_{2}\) content is 50%, the flame does not exist. As observed in the temperature analysis, a reduced amount of hydrogen considerably improves combustion stability. Even registering large fluctuations in the combustion, the conventional burner can maintain the flame for every experiment tested, except for BG50, which requires 15% hydrogen to ignite but 20% to maintain a weak flame. In accordance with other laboratory combustion devices, the addition of hydrogen improves the combustion behavior. This tendency complies with the temperature results [48]. Hydrogen has a wider flammability range and a higher heating value than methane and, hence, the hydrogen addition extends the flammability limits and, consequently, flame stability.