esa-sceva/satcom-chunk-collection huggingface dataset:
# Quotient Network-A Network Similar to ResNet but Learning Quotients
## 4 Experiments
### Datasets  
**CIFAR10/CIFAR100.** Both datasets are composed of 32 \(\times\) 32 RGB images, of which CIFAR10 has a total of 10 categories, and CIFAR100 has a total of 100 categories. The two datasets have the same number of training and test sets, where the training set consists of 50,000 images, and the test set consists of 10,000 images. We randomly select 5000 images from the training set as the validation set, and the remaining 45,000 are used for training. Finally, we report the results of the test set. For data augmentation, we perform a random horizontal flip of the image, fill all sides with 4 pixels, and then randomly crop a 32 \(\times\) 32 image. Finally, we normalize the data using channel means and standard deviations. For testing, we only evaluate the single view of the original 32 \(\times\) 32 image (including subtracted by the mean and divided by the std).  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**\#Params**} & \multicolumn{2}{c}{**Quotient Network**} & \multicolumn{2}{c}{**ResNet**} \\ \cline{2-5}  & **Network** & **Accuracy (\%)** & **Network** & **Accuracy (\%)** \\ \hline
0.68 M & quotient network44 & 92.78 \(\pm\) 0.25 & Resnet44 & 92.61 \(\pm\) 0.33 \\
0.87 M & quotient network56 & 93.1 \(\pm\) 0.15 & Resnet56 & 92.84 \(\pm\) 0.18 \\
1.75 M & quotient network110 & 93.44 \(\pm\) 0.17 & Resnet110 & 93.02 \(\pm\) 0.33 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Comparison with ResNets of different layers on the CIFAR10 dataset. Results are expressed as “mean \(\pm\) std”.  
**SVHN.** The street view house numbers (SVHN) dataset consists of 32 \(\times\) 32 images, with 73,257 as the training data set and 26,032 as the test data set. We randomly select 6000 images from the training set as the validation set, train on the remaining 67,257 images, and then test on the test set and report the results. In data preprocessing, we normalize the data using the channel means and standard deviations.
## 3 Results and Discussions
### Effects of Radiation from Localized Hot Spots  
It should be noted that the view factor for radiation heat flux calculation is based on the assumption that Cell 5 has a uniform surface temperature. Under certain conditions, the presence of localized hot spots may result in a non-uniform battery surface temperature, which may complicate the nature of radiative heat transfer. In such a case, the problem is no longer symmetric, similar to the one discussed in the previous sub-section. Therefore, radiative heat flux to each cell must be calculated separately. In order to investigate such effects, localized hot spots are introduced as shown in Figure 14, represented by the blue arc segment on the surface of Cell 5. The size of the hot spot is characterized by the angle \(\varphi\)  
Figure 15: Comparison of view factors among different adjacent cells in orthogonal arrangement in Figure 14.  
shown in Figure 14, while the center of the hot spot is located along the center line of Cells 5 and 2. This hot spot is assigned a representative temperature of 750 K, while the rest part of Cell 5 is assumed to be at 300 K. A cell-to-cell gap of 1 mm is assumed. As we change the hot spot size, it is expected that both the radiative surface area and the view factor will vary accordingly.  
Figure 16 shows the radiative heat flux per unit receiving surface area for hot spot sizes of 20\({}^{\circ}\), 45\({}^{\circ}\), 90\({}^{\circ}\) and 360\({}^{\circ}\). In the 360\({}^{\circ}\) case, we observe that each radiative heat flux on Cells 2, 4, 6, and 8 accounts for 17% of the total radiation and that each radiative heat flux on Cells 1, 3, 7, and 9 accounts for 8%, consistent with their corresponding view factors shown in Figure 15. With a reduced hot spot size to 90\({}^{\circ}\), more than 60% of the total radiation is received by Cell 2, the closest one to the hot spot, with a similar radiation heat flux on Cell 2 to the 360\({}^{\circ}\)case. With further reduced hot spot sizes to 45\({}^{\circ}\) and 20\({}^{\circ}\), the radiation flux is reduced as expected: 80% and more radiation from the hot spot is directly emitted to the closest Cell 2. This shows that the nature of radiative heat transfer between cells, and, thus, the nature of thermal runaway propagation depends on the size of the hot spot. Mitigation strategies, therefore, must account for the nature of the hot spots expected.  
In the limiting case of an infinitely small hot spot, it can be shown that the view factor from the hot spot to an adjacent circle degenerates to R/H. This theoretical result can be applicable to highly localized hot spots, such as small, hot particles from venting events.
# Analysis of Vehicle-Bridge Coupling Vibration Characteristics of Curved Girder Bridges
## 4 Spatial Vibration Analysis of the Coupled Time-Varying System of Vehicle-Curved Grider Bridge
### Analysis of the Influence of Constraint Methods  
Two types of constraints were selected. One was to set the boundary conditions of the bridge model to the general constraint arrangement of straight bridges in a rectangular coordinate system, similar to the general support constraints of a common straight bridge, i.e., constraining the nodes' degrees of freedom in the overall coordinate system (short as the rectangular coordinate system in the following text). The other was to set the boundary conditions of the curved girder bridge by setting rigid connections in the radial and standard directions of the fulcrum in a polar coordinate system (short as the polar coordinate system in the following text). Based on the above bridge and vehicle models, the Timoshenko curved beam element was utilized to discretize the structure, and the self-written program was used to consider the good-grade deck roughness. The vehicle-bridge coupled dynamic response was calculated when a heavy truck with a speed of 40 km/h passed through the curved bridge, and the influence of constraint ways on the vehicle-bridge coupled vibration of the bridge was discussed.  
The comparison of the indexes such as the displacement and the acceleration time-history responses in the mid-span of bridges under different restraint modes is in Figures 10-12, and the comparison of peak responses in the mid-span of bridges is summarized in Table 3.  
Figure 11: Mid-span vertical acceleration curves under different constraints.  
Figure 10: Mid-span vertical displacement under different constraints.  
As shown in Figures 10-12 and Table 2, different constraint methods of the bridge significantly affect bridge dynamic responses. Compared to the polar coordinate system, the bridge vertical and torsional dynamic responses under the rectangular coordinate system constraint were more extensive, with the vertical displacement peak increasing from 1.890 mm to 5.756 mm, the vertical acceleration peak increasing from 0.124 m/s\({}^{2}\) to 0.363 m/s\({}^{2}\), and the torsional displacement peak increasing from 0.753 \(\times 10^{-4}\) rad to 0.113 \(\times 10^{-3}\) rad.
# Apollonian Packing of Circles within Ellipses
## Appendix A Deduction of Hyperbola Parametrization Formulas
### Choice of the Correct Hyperbola Branch  
By means of a suitable choice for the \(\pm\) symbol and parameter \(t\) in Equation (11), point \(P\) describes four semi-branches of hyperbola \(\mathcal{I}\), shown in Figure 11a. In particular:  
* By using the \(\pm\) sign in the parametrization, point \(P(t)\) describes right branch \(\mathcal{I}^{a}\) or left branch \(\mathcal{I}^{b}\).
* By using values \(t\gtrless 0\) in the parametrization, point \(P(t)\) describes upper semi-branches \(\mathcal{I}^{a+}\) and \(\mathcal{I}^{b+}\) or lower semi-branches \(\mathcal{I}^{a-}\) and \(\mathcal{I}^{b-}\). In the search for circle \(\mathcal{C}_{t}\), which is externally tangent to circles \(\mathcal{C}_{1}\) and \(\mathcal{C}_{2}\) and tangent to elliptic boundary \(\mathcal{E}\), it is necessary to pay particular attention to the choice of the suitable hyperbola semi-branch on which center \(C_{1}\) must be searched for. By taking into careful considerations all possible arrangements of the tangency geometrical layout, a procedure for the choice of the hyperbola semi-branch may be described as follows:
* In Equations (10)-(12), it is important to ensure that condition \(\overline{CC_{1}}=r_{1}>r_{2}=\overline{CC_{2}}\) is satisfied (i.e., \(\mathcal{C}_{1}\) must be the largest circle).
* In Equations (10), only the \(+\) determination of the \(\pm\) sign is used (i.e., only the right branch of \(\mathcal{I}^{a}\) is taken into consideration).
* The negative sign for parameter \(t\) is chosen only in the two cases of \(\varphi>\pi/2\) or \(x_{T_{1}}>x_{T_{2}}\), with \(T_{1}\) and \(T_{2}\) being the tangency points between boundary ellipse \(\mathcal{E}\) and circles \(\mathcal{C}_{1}\) and \(\mathcal{C}_{2}\).
# Mechanical Behavior of Weathered Granite Exposed to Water
###### Abstract  
Weathered granite has been widely used as an emerging foundation filler for constructing transportation infrastructure. However, various softened rocks weathered due to exposure to water have special properties. Thus, it is necessary to gain a thorough understanding of the various physical and mechanical properties of weathered granite after exposure to water in order to avoid engineering accidents. To this end, this paper conducted a series of undrained triaxial shear tests to compare the mechanical behavior of weathered granite in natural and saturated states. The results demonstrate that the strength of the weathered granite significantly declines when it is exposed to water, and it exhibits noticeable water softening characteristics. Consolidation methods also affect the mechanical properties of weathered granite. The degree of softening of weathered granite decreases with an increase in the deviator stress imposed by the deviator stress consolidation. Subsequently, we established an empirical model for the strain softening of weathered granite suitable for natural and saturated conditions. This model took the elastic modulus of weathered granite before the peak strength as a measure and introduced the strength parameters of the internal friction angle (\(\varphi\)) and the internal cohesion (c). First, the fitted function correlating c and \(\varphi\) with the plastic internal variable was determined, and then the relationship between the strength and the strain-softening parameters was established so as to obtain the complete stress-strain curve of the granite rock. Finally, validation studies were performed to address the capability of the model to predict permanent deformation. It provides a theoretical basis for predicting and calculating the strain softening of weathered granite exposed to water.  
weathered granite; mechanical behavior; strain softening; deviator stress consolidation; empirical model +
Footnote †: journal: Applied Sciences
## 2 Starch Modification Processes
### Chemical Modifications
#### 2.4.7 Grafting  
During grafting, synthetic or natural polymers are introduced to the backbone of the starch. The graft polymerization can tailor the chemical and physical properties of starch without changing the biodegradability [69]. The major sites for initiating graft copolymerization are localized at Cl-C2 end groups and C2-C3 glycol groups. Acrylate esters, methacrylate esters, and styrene are commonly used for graft polymerization. The hydrophobic grafted branches make starch less hydrophilic than unmodified starch. In addition, grafted starch is biodegradable and possesses higher tensile strength and a better appearance than unmodified starch [69]. However, the TPS grafted with polylactic acid exhibited lower tensile strength than native TPS, with the tensile strength of 2.40 MPa and 0.06 MPa for native and grafted TPS, respectively [79]. Even though the tensile strength of grafted starch decreased, the elongation at break increased by 120% [79]. This study also reported a lower Tg for grafted starch than native starch due to the role of grafted starch as an internal plasticizer, making micro-and macro-level changes [69]. Moreover, starch graft-copolymers with acrylate, methacrylate esters, or styrene are mainly used to prepare starch-filled plastics due to the compatibility of grafted starch with the plastic matrix [69].  
The grafting reaction of starch is a free radical reaction and thus requires the treatment of initiators to yield free radical sites on the starch chain. After that, the starch chain acts as macro-initiators in the presence of synthetic monomers to obtain polymer grafts of high molecular weight [98]. [PERSON] et al. [88] prepared the cassava starch-poly (methyl methacrylate)-(CS-g-PMMA) copolymers. The results indicated that the presence of poly (methyl methacrylate) grafts improved the thermal stability of starch, and SEM micrographs exhibited a strongly deformed structure of CS-g-PMMA copolymer granules. The grafted starch also showed a higher thermal decomposition temperature of 332 \({}^{\circ}\)C than native corn starch.
# Overview of Mobile Communications in Colombia and Introduction to 5G
## 1 Introduction
### Current Networks
In this context, Colombia is lagging in 4G coverage, and a large part of its territory (especially in rural areas) is covered by 2G and 3G networks. Although more than 80% of households in most of the departments that make up Colombia's political-administrative structure have access to cellular telephony, in most of its territory, the percentage of households with Internet access is less than 53% (see Figure 2) [20]. Despite the fact that mobile telephony penetration in Colombia is high (131.6% approx.) [11], 2G and 3G coverage account for a large part of the coverage (31%). This last statistic indicates a significant disadvantage for the country when compared to Europe (21%), North America (9%), and China (2%). However, the situation improves when compared to North Asia (50%), Asia-Pacific (34%), and North Africa (58%). In Latin America, the percentages for Colombia are similar to those of the rest of the region (31%) [19]. It is undeniable that the increase in coverage and quality of mobile telephony services contributes to the social and economic growth of the states. For this reason, if Colombia is to have a digital society and economy framed by the industry 4.0 concept, it is important to move quickly to replace the current 2G and 3G networks in favor of 4G and 5G. There is no consolidated information on the average speed rates of downstream and upstream channels of all operators providing service in Colombia, much less by region or department. Possibly because these providers do not offer broadband services, i.e., they do not guarantee a minimum speed and focus on offering per-download plans for some time (usually for a calendar month). However, statistics reported by MinICT in its fourth quarterly report for 2021 show a growing trend in mobile subscription Internet access. In addition, the average traffic in this type of access has also increased in the last two years, demonstrating the inclination of subscribers towards the use of mobile systems as an Internet access technology [21]. This growth is supported by several factors, such as increased speed, increased coverage, and lower tariffs.
## 4 Discussion  
After successful application of the breast imaging prototype in the laboratory by means of breast phantoms [21], the present work shows first imaging results from breast cancer patients. The clinical measurements represent an important step forward towards the larger acceptance of microwave imaging techniques for medical diagnostics. A major advantage of the proposed system compared to other microwave methodologies is given by simple image formation, which does not require large computational resources. For each measurement, only the inverse Fourier transform must be computed followed by the calculation of the RMS-value for the pixel amplitude at a specific \(x\)-\(y\) coordinate. This means that the whole processing chain can be implemented on a microcontroller platform rather than a powerful work station, which is beneficial in terms of reduced system costs and reduced computation time. Portability is an additional feature due its compact size.  
The dielectric properties within the breast change locally and beamforming procedures struggle with finding the optimal values for the relative permittivity to realize a proper focussing. Digital beamformers might be improved by studying more complex techniques that take the distribution of relative permittivity into account [22]. In any case, generally the information about the breast's permittivity is not available on a patient-specific basis and can only be estimated on average [23]. An advantage of the proposed RMS-approach is given by the fact that information about wave propagation inside the breast, e.g., in terms of wave speed, is not required.  
Another benefit of the proposed system is the ability to deal with variable breast sizes and shapes by compressing the breast similar to X-ray mammography. This approach avoids inserts that are often used in three-dimensional imaging systems [6] to compensate for variations in breast size. Exploiting the transmission signals through the breast also eliminates the need for surface artifact removal algorithms before the image formation [24]. A drawback of the proposed approach might be given by the compression-induced pain during examination. According to the patients' feedback, this pain was acceptable.  
We are aware that the study has limitations in terms of the number of patients that have been examined. Further limitations are given by the relatively long scan time, which limits the inspection area to about \(50\,\mathrm{mm}\) by \(50\,\mathrm{mm}\). This could be improved by additional engineering that uses multiple transmitters and receivers either in a static or moveable linear array. In that case, the measurement time can be reduced to about 20 seconds with a full coverage of the breast. Finally, it can be said that the preliminary results shown here are encouraging to study the planar microwave imaging system in more detail in the future. With that being said, we aim at \"designing sufficiently powered, large-scale clinical trials to address sensitivity and specificity\" [18]. Such clinical trials are important for a statistical analysis to evaluate the MWI systems performance.
# Biomethane Potential Test: Influence of Inoculum and the Digestion System
## 2 Materials and Methods
### Measurement Procedure  
All BMP tests were performed according to VDI 4630 at ISR \(>\) 2 and a temperature of 38 \(\pm\) 0.5 \({}^{\circ}\)C. In all digestion systems, beside D-HBT1 and D-HBT2, tests were performed in three replicates and digestion was terminated according to the 0.5% criteria, i.e., when the increase in gas production was less than 0.5% d\({}^{-1}\) for three days. In both D-HBT, tests were performed in six replicates. Digestion time was terminated after 35 d, whereby the 0.5% criterion was met in each test run. Specific methane yield was calculated for biogas yield and methane percentage that were measured for each test run. Gas volume was corrected to standard conditions of 101.33 kPa and 0 \({}^{\circ}\)C.  
Investigated combinations of digestion systems, substrates and inocula are listed in Table 7. All substrates were tested in all digestion systems. However, the full range of inocula was only tested in D-HBT1, which was chosen because of the low sample volume (30 mL) required and its high repeatability. With the other digestion systems only one or two inocula could be tested due to the limited number of reactors for parallel tests (Table 7). Additionally, trials with supplementation of TE for all inocula in D-HBT1 on substrate S-DMS were performed by adding a TE solution as described by [PERSON] et al. [3]. In this test series, blanks for all inocula were also tested.  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Code** & **Name of Substrate** & **DM \%** & **Ash \%** & **Fat \%** & **Protein \%** & **Fiber \%** \\ \hline S-HAY & Hay & 94.2 & 5.4 & 1.0 & 9.2 & 31.8 \\ S-DMS & Dried maize silage & 92.8 & 4.3 & 2.3 & 7.4 & 18.7 \\ S-TGF & Triglyceride fodder & 93.0 & 10.4 & 24.4 & 19.8 & 8.5 \\ S-CON & Concentrated fodder & 92.8 & 7.1 & 2.6 & 18.4 & 7.4 \\ S-MCC & Microcrystalline cellulose & 96.8 & \textless{}0.3 & \textless{}0.6 & \textless{}0.5 & 59.4 \\ \hline \end{tabular}
\end{table}
Table 6: Characterization of the substrates in percentage of dry matter content (DM), ash, fat, protein, and fiber in percentage of fresh matter.
# Reliable Positioning and mmWave Communication via Multi-Point Connectivity +
## 2 System Model
### Signal Model  
This section provides a generic signal model for system architecture shown in Figure 1. For the simplicity of analysis, we assume that each transmission frame is of duration \(T_{f}\) and is divided into two non-overlapping phases: training and data, as illustrated in Figure 2. Training phase of duration \(T_{t}\) is reserved for channel estimation and obtaining best receive beams from each BS to each MS. While the UL users are transmitting their pilots for UL training, each BS independently scans through the set of receive beams \(\mathbf{w}_{b}\in\mathcal{W}_{b}\), where \(\mathcal{W}_{b}\) is the fixed receive beamforming codebook of \(b\)th BS and each receive beam can be selected through a switching circuitry. Unless stated otherwise, we use superscripts \(d\) and \(p\) for the variables related to data and pilot, respectively. The pilot signal for user \(k\) and BS \(b\) during the training phase of duration \(T_{t}\) for a given receive beam \(\mathbf{w}_{b}\) can be written as  
\[y^{p}_{b,k}(t)=\mathbf{w}^{\mathrm{H}}_{b}(t)\mathbf{h}_{b,k}x^{p}_{k}(t- \tau_{b,k})+\mathbf{w}^{\mathrm{H}}_{b}(t)\mathbf{n}_{b}(t)\,,\ \forall k,\ \forall b\,, \tag{3}\]  
where \(\mathbf{w}_{b}(t)\in\mathcal{W}_{b}\) is the analog receive beamforming vector at time \(t\) from BS \(b\), obtained by both amplitude scaling and phase-shift to each each antenna element. The propagation delay \(\tau_{b,k}=\|\mathbf{q}_{b}-\mathbf{p}_{k}\|/c\) is computed for the dominant LoS link with \(c\) denoting the speed of light, and \(\mathbf{n}_{b}(t)\ \forall b\) is circularly symmetric additive-white-gaussian-noise (AWGN) with power-spectral-density of \(N_{o}\). Finally, continuous time signal \(x_{k}(t)\) has bandwidth \(B_{t}\) and duration \(T\) with \(1/T\int_{0}^{T}\ |x_{k}(t)|^{2}dt\ =\ P_{k},\ \forall k\).  
The reminder of duration \(T_{d}\) is used for uplink data reception using a fixed analog beam at each BS. For simplicity, we assume full-cooperation scenario, i.e., all BSs receive signal from all active users in the system. However, in practice, the maximum number of coordinating BSs associated to each user is always limited because of path-loss with the distant BSs, finite capacity of fronthaul links and corresponding signaling overhead with the BBU.  
Figure 1: Uplink Communication system model showing receivers (BSs) and transmitters (users) with the LoS link and random blockers.
## 2 Materials and Analytical Methods
### Analytical Methods
#### 2.4.2 Antioxidant Activity Analysis by ABTS Assay  
The ABTS assay was performed according to the analytical method presented by [PERSON] et al. [31] with slight modifications. Initially, the ABTS working solution was prepared by mixing 2.4 mM of potassium persulfate with 7.5 mM of ABTS. Subsequently, these reagents were allowed to react with each other in the dark at room temperature for 12 h. PBS buffer solution of pH 7.4 was used to dilute the ABTS working solution in order to reach its absorbance at the level of 0.7 \(\pm\) 0.02 at 734 nm. In the next step, the reaction between 40 \(\mu\)L of SCG extract and 4 mL of the resulting ABTS solution was conducted for 6 min in darkness. After the desired duration time of the reaction, the absorbance of the tested solution was registered at 734 nm. The Trolox in PBS buffer standard solutions were used for calibration. The ABTS assay results are presented as mg of Trolox per gram of spent coffee grounds dry matter (mg Trolox/g SCG d.m.).