esa-sceva/satcom-chunk-collection huggingface dataset:
###### Abstract
Most of the previous studies have not considered the size-dependent effects due to the complexity in reflecting polydispersity implying that f(RH) is to be assumed constant regardless of the size [16]. However, many theoretical and empirical studies have suggested that individual chemical substances should be specifically assessed based on their size [3; 17; 18; 19; 20]. From a theoretical point of view, f(RH) should be recalculated using a thermodynamic model and the Mie theory for each size distribution. Thus, it is important to understand the size dependency of f(RH), and it is necessary to investigate whether it has a serious sensitivity or uncertainty with respect to aerosol hygroscopic growth factors upon considering size effects. The remainder of this paper is organized as follows. In Section 2, the operational model and data are introduced, and the estimated AOD algorithms are summarized. A qualitative comparison between satellite images and estimated AODs is presented in Section 3; in addition, a more quantitative analysis focused on the Seoul metropolitan area is presented along with detailed statistical results for the entire domain of the NIER operational model. Section 4 summarizes the results of the study.
## 7 Research Directions
In such way, the priority of source nodes may be chosen based on the proximity of the target event or based on some other factors. Additionally, source nodes with different priorities may apply different encryption strategies, where more relevant sources may process more robust encryption algorithms to assure higher security for the most relevant data for applications, while lower-relevant data may have weaker security, balancing the overall computational costs of the network. Thus, global-level QoS combined with selective encryption can be a promising future research line to provide security in wireless image sensor networks. Selective encryption may be applied for other types of data, such as audio and video, not only for images. The principle is the same, _i.e._, the combination of coding algorithms with encryption. Then, audio and video coding algorithms can be studied more thoroughly in order to find potential optimization opportunities. Codecs, like MPEG4 for video, and MP3, MPEG2 AAC, MPEG4 AAC, TwinVQand Dolby AC3 for audio [45] may be considered for wireless multimedia sensor network applications. Heterogeneous multimedia sensors may be widely available at very low cost in near future. An envisaged research trend is the use of both encoding and encryption algorithms adapted to the hardware of sensor nodes. In other words, the idea is that depending on the hardware of sensor nodes, whether it is more robust in processing capabilities and memory, coding and encryption algorithms may also be more robust, with more overhead and ensuring a higher security level without significantly prejudicing the network operation. Selective encryption can be designed so that protocols can automatically detect hardware resources of sensor nodes. More robust approaches may employ selective encryption and watermarking to provide higher security to image transmissions in wireless sensor networks. Future works may combine those approaches in security frameworks for WISN. Actually, authenticity will be a central concern, since there will be a demand for trustworthy wireless visual sensor networks. Integration of wireless sensor networks with public networks, like the Internet, may be required for some applications, also bringing new challenges when providing security [91]. Although these are promising research areas in the field of secure wireless image sensor networks, new challenges may emerge, fostering investigation efforts in this area.
## 1 Introduction
However, a comprehensive theoretical analysis of all (or nearly all) radiometric quantities (including plane and scalar irradiances) as well as the three AOP classes (\(K\)-coefficients, reflectances, and average cosines) throughout the water column for a variety of complex environmental scenarios is not easily tractable, especially for various naturally-occurring vertical profiles of IOPs within the upper ocean. Such analysis has usually remained beyond the scope of RT modeling; rare examples are found in [PERSON] and [PERSON] [60], which focused on the well-lit upper ocean layer, and [PERSON] et al. [64], which focused on the dimly-lit mesopelagic zone (\(z>200\) m). [PERSON] and [PERSON] [60] demonstrated, for example, the intricate patterns of the influences of many factors, including the sun position, seawater IOPs (as driven primarily by chlorophyll-\(a\) concentration, \(Chl\), and co-varying water constituents), and Raman scattering, on the various AOPs within a hypothetically homogeneous ocean. In spite of decades of experimental and theoretical studies of optical radiometry of the ocean, there exist some gaps or interesting questions, which deserve further attention. This study has been motivated by a few such questions, in particular (i) how the spectral and vertical patterns of light field characteristics and AOPs are affected by the interplay of inelastic processes (i.e., Raman scattering and chlorophyll-\(a\) fluorescence) and the actual non-uniform vertical distributions of \(Chl\) (and hence the vertically varying IOPs) within the euphotic layer; (ii) what relationships can be established between different AOPs using the depth-resolved data within the euphotic layer; and (iii) what is the quality and applicability of estimation of seawater absorption coefficient from measured AOPs and Gershun's equation under real conditions of non-uniform vertical distributions of \(Chl\) and IOPs, and inelastic processes within the euphotic layer. To address these questions, we collected simultaneous hyperspectral measurements of the irradiance quartet (\(E_{d}\), \(E_{u}\), \(E_{od}\), and \(E_{ou}\)) and the zenith radiance \(L_{u}\) from the surface to depths of 60-80 m in the Gulf of California. This dataset is unique because it allows conducting a case study of a comprehensive set of radiometric quantities and all essential AOPs for a broad range of specific optical and biogeochemical conditions within the water column as described by the actual vertical profiles of \(Chl\) and IOPs.
###### Abstract  
A series of citrate salts were tested as hydrogen bond acceptors to synthesize deep eutectic solvents (DES) based on lactic acid and glycerol, used as hydrogen bond donors. The DES produced were then screened to identify the highest performing system for the effective extraction of polyphenic phytochemicals from the medicinal plant _Salvia fruticosa_ Mill. (Greek sage). The most efficacious DES was the one composed of lactic acid and sodium citrate dibasic, at a molar ratio of 15:1 (LA-SCDB15). Furthermore, for the first time there has been evidence concerning DES pH and extraction efficiency. Using this solvent, a batch, stirred-tank extraction process was developed, by employing ultrasonication pretreatment and response surface methodology. The optimal settings determined were stirring speed 900 rpm, proportion of DES/water 77% (_w/v_), and ultrasonication pretreatment time 15 min. By adjusting these optimal settings, the predicted maximum total polyphenol yield was calculated to be 79.93 \(\pm\) 1.92 mg gallic acid equivalents g\({}^{-1}\) dry mass. The examination of temperature effects demonstrated that the batch, stirred-tank extraction stage was very energy-efficient, with a barrier of 7.64 kJ mol\({}^{-1}\). Comparison of the extraction of _Salvia fruticosa_ polyphenols with other green processes previously developed, illustrated the high extraction capacity of LA-SCDB15. The major polyphenols identified in the extracts produced under optimized settings were chlorogenic acid, luteolin 7-O-glucuronide and rosmarinic acid.  
Keywords: antioxidants; deep eutectic solvents; extraction kinetics; polyphenols; _Salvia fruticosa_; ultrasonication +
Footnote †: journal: Applied sciences
# Analysis of the Scalability of UWB Indoor Localization Solutions for High User Densities
## 1 Introduction  
Ultra-wideband (UWB) radios are very popular for accurate indoor localization. Their main unique technology feature is the use of a large frequency band (\(\geq\)500 MHz) that utilizes trains of pulses with very short duration (less than 1 ns). UWB radios are able to precisely differentiate between pulses that are reflected from different objects. As a result, this technology is very robust to multipath fading, which is crucial in challenging situations such as indoor localization. This timing resolution capability is used for accurate range measurements when UWB is deployed in a Real-Time Locating System (RTLS). Today UWB radio prices are dropping and as such, they are becoming more affordable to the broad market. This explains the great interest in the subject by the scientific community, resulting in a large quantity of recent scientific papers [1; 2; 3] focusing on UWB indoor localization solutions.  
UWB has still some open issues prior to becoming a successful indoor localization choice. The standard imposes certain physical layer (PHY) guidelines such as transmitting power, which may impact the scalability of the system while making it robust against interference with other technologies. Although many scientific papers about UWB localization are available, most of these focus on improving the accuracy of the localization system, without considering scalability aspects. Current UWB localization solutions from scientific literature are typically designed for localizing at most tens of mobile devices (tags) and are evaluated in a small (office) environment or open space area. For example, studies in [2] and [4] demonstrate the high accuracies that can be obtained using UWB (respectively 11 cm and 3.25 mm without post processing), but they are limited to localizing one or two tags in a small area i.e., an office room. Some commercial solutions became recently available and they advertised high update rates but do not mention the conditions in which it is possible. To analyze the scalability of UWB, this paper provides a regulatory overview, an analysis of the impact of design choices (PHY, MAC and localization approach) that can be made for UWB system design and the mathematical framework to calculate the user density based on these choices. Furthermore, to validate the models, we applied them to realistic UWB deployment scenarios.  
The remainder of the paper is organized as follows. Section 2 discusses related work. Afterwards Section 3 introduces UWB standard regulations and PHY considerations while, Section 4 focuses on MAC layer aspects as well as the two considered localization techniques, namely TDoA and TWR. Next, Section 5 introduces the scalability models to evaluate the tag density. Finally, in Section 6 the model is applied using realistic settings and schemes of a commercially available UWB chip, followed by the conclusions.
## 3 Finite Element Simulations
### Impact Echo Simulation Results  
The model for the impact echo (IE) was based on the same model of a 1.0 m \(\times\) 1.0 m \(\times\) 0.2 m concrete slab (Figure 1) with Perfect Match Layers (PMLs) on all four sides to prevent the reflection of elastic waves. The model includes a loading plate and measurement points to represent the impact area and transducer location, respectively. The transducer was positioned 5 cm from the impact point, as shown in Figure 8. The IE test was simulated using a half-sine wave pulse  
Figure 7: ER for the models: (**a**) for sound concrete; (**b**) with AFD at different depths; (**c**) with WFD at different depths.  
with a maximum force of 1 N and a duration of 50 microseconds. Poisson's ratio for concrete is 0.2, the speed of the compression wave (P-wave) is 4000 m/s, and the speed of the shear wave (S-wave) is 2312 m/s.  
As shown in Figure 1b, an ultra-fine mesh was utilized in the vicinity of the transducer and impact point. The purpose of this mesh was to achieve a highly accurate simulation of wave propagation for the IE technology. The maximum size of the free tetrahedral element was set to 0.001 m, with a growth factor of 1.2.  
The effect of the impact echo can precisely determine the plate-like structure's thickness. The thickness is calculated based on the dominant frequency and the velocity of the P-wave in the material, as illustrated in [21].  
\[T=\frac{\beta C_{p}}{2f} \tag{1}\]  
where  
\[T=\textit{the depth of the reflector}\] \[\beta=\textit{the correction factor }(0.96\textit{ for plate }-\textit{like structures})\] \[C_{p}=\textit{the P-wave velocity}\] \[f=\textit{the dominant frequency}\]  
Acceleration time history plots of the sound and defective concrete models are displayed in Figure 9, while the corresponding frequency spectra for both models are shown in Figure 10. The frequency spectrum of the impact echo tests on the sound concrete, as seen in a blue line in Figure 10, reveals that the main frequency is 10,000 Hz. This leads to a calculation of the concrete slab's thickness of 0.192 m using Equation (1), which is nearly the same as the actual thickness of 0.200 m. On the other hand, the dominant frequency caused by the flaw (a 5 cm deep crack), shown as a red line in Figure 10, is 34,900 Hz. The calculated depth of the crack in the concrete slab using Equation (1) is [0.96 \(\times\) 4000/(2 \(\times\) 34,900)] = 0.055 m, which is very close to the known crack depth of 0.050 m.  
Figure 8: B-B cross-section for sound concrete.
# Software Defined Wireless Mesh Network Flat Distribution Control Plane
## 3 Architecture Implementation
### Agents Implementation  
Agents use the coordinator to exchange information between distributed controllers among neighboring domains. In this architecture, four agents were developed: Reachability, Connectivity, Monitoring and Reservation (see Section 2.3). They publish on particular topics, e.g., monitoring.C_ID.bandwidth.2s where the monitoring agent at a controller that is identified by C_ID advertises the remaining bandwidth it can offer for traffic transmission. Any received information from neighboring domains' agents is stored in the aggregated-DB of the local agent. Then this information is used by the modules of the local controller to take a decision on flows over the network.  
For end-to-end provisioning, the reservation agents implement a mechanism like RSVP reservation protocol, they exchange reservation requests responding to flow descriptors. The development of the coordinator and its assistants (drivers, agents, etc.) adds extra lines of code and their operation consumes extra memory of the POX controller.
## 4 Radiation Analysis
### Radiation Simulations Results
#### 4.2.4 Extravehicular Mobility Units on the Moon  
On the Moon, astronauts are likely to be involved in extensive surface expeditions on a daily basis. Thus, contrary to extravehicular activities (EVA) at the ISS, a considerable amount of mission time will be spent under low radiation protection conditions of the suit. The use of Kevlar is not new in space, as it is one of the protective layers of the extravehicular mobility units. However, the utilisation of Kevlar can be enhanced and it can serve as radiation protection as well. Kevlar has radiation effectiveness comparable to that of polyethylene [19]. The layer of Kevlar can be thickened in EMUs for surface exploration on the Moon. For a simulation of the GCR conditions for six h on the Moon to represent an average EVA time, three layers of different kinds were considered as EMU materials, the in-most neoprene layer of 3 mm followed by silica aerogel and Kevlar 1 mm each. This gave 0.32 mSv of the total effective dose equivalent, which when compared to 0.19 mSv received by a fellow astronaut staying in the habitat behind a multilayer structure with 104 g/cm\({}^{2}\) of regolith suggests that the spacesuit protects one relatively well. The scenario is illustrated in Figure 6.  
The calculated daily dose rate of 1.3 mSv/d falls within the reported Apollo range of 0.7-3 mSv/d [23], and as it converts to 0.38 mGy/d, it is also in good agreement with the measurements of the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) aboard the LRO with a very low altitude of 50 km. The CRaTER measured 0.22-0.27 mGy/d [23] between 2009 and 2010, which is the solar minimum at the beginning of cycle 24. Therefore, the simulated surface exploration scenario can provide a robust estimation of the daily EVA contribution to the total effective dose equivalent, which is on the order of magnitude of 1-2 mSv/d.  
\begin{table}
\begin{tabular}{l c c c} \hline \hline \multirow{2}{*}{**Dose in CAF**} & \multicolumn{2}{c}{**Shielding**} & \multirow{2}{*}{**Relative Change**} \\ \cline{2-2} \cline{4-4}  & **Aluminium (3 cm)** & & **Aluminium (3 cm)-Polyethylene (5 cm)** \\ \hline Effective, GCR BON 20141 day (mSv) & \(1.1\) & 0.95 & 13.6 \\ BFO, August 1972 SPE (mGy-Eq.) & 225.6 & 85.8 & 62 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Effective and BFO doses in CAF for the lunar rover.
## 2 Principle of OSC Systems and LG Modes
### LG Modes for OAM Generation  
There are two basic phenomena in light propagation through free space, such as (1) with the propagation of light in OWC, a significant change in the intensity profiles of light has been observed; and (2) modes of light (i.e., electrical field distribution) cannot change with the transmission through free space. The direction of the variation in the electrical field remains constant only; however, other components such as phase, profile, and receiver power of light keep on changing. The generation of LG and HG modes is the outcome of constant electrical field distribution of light in wireless mediums. Both LG and HG modes differ in structure shape such as LG modes have a horizontal circular structure and HG modes have a vertical helical structure. Preferred modes for the communication systems and OAM are LG modes due to their simple multiplexing/de-multiplexing and can have a significant gap in the rings depending upon \(l\). The LG mode profile depends on the focus point, the axis of the beam, the optical frequency, and the radius of the beam. Doughnut, like the shape of LG modes, has a helical phase front and it is expressed as [56]  
\[\Psi_{lm}(r,\varnothing)=(\frac{2r^{2}}{w_{0}{}^{2}})^{|l|}L_{m}^{l}\left( \frac{2r^{2}}{w_{0}{}^{2}}\right)\exp\left(\frac{r^{2}}{w_{0}{}^{2}}\right) \exp\left(j\frac{\pi r^{2}}{\lambda R_{0}{}^{2}}\right)t_{\sin\left(l|\phi \right),l\geq 0}^{\cos\left(|l|\phi\right),l<0} \tag{4}\]where X and Y indices are the \(l,m\) indexes, light profile radius R, spot size \(w_{0}\), Laguerre polynomial \(L_{lm}\), z direction spot size \(w(z)\). Diverse profiles of light can be generated in LG modes by changing the \(l,m\) numbers, for example, LG00 is generated by fixing \(l,m\) at \(l=0,m=0\), and LG100 is obtained by entering \(l=10,m=0\) as shown in Figure 2.  
The number of peaks in the light profile is a function of \(l\) and the boundary around these peaks varies with \(m\). These different LG modes with distant values of \(l\) are combined to realize OAM multiplexing for high-speed OWC systems.
# Fatigue Crack Growth from Notches:
## 5 Discussion  
The FCG rate of cracks growing from notches can be explained by the following mechanisms:  
* Two transient effects, one associated with the stabilization of cyclic plastic deformation and the other associated with the built of plasticity induced crack closure. The former, which is very evident in unnotched cracked specimens without contact, needs a very short crack propagation to  
Figure 12: Evolution of \(U^{*}\) with \(\Delta a\) for different notch radii: (**a**) AA6082-T6; (**b**) AA7050-T6 with kinematic hardening; and (**c**) AA7050-T6 with isotropic hardening (notched cracked specimen, contact; plane stress).  
disappear. The stabilization of crack closure level is much longer, depending on material and increasing with the decrease of notch radius;  
The influence of the notch fields. The reduction of notch radius increases \(\delta_{p}\), and therefore FCG rate, and substantially reduces the extension affected by the notch. Without contact, the limit of notch influence zone has only been reached for the smallest radius studied (\(r=1\) mm);  
The crack closure phenomenon, which has a dramatic effect under plane stress conditions and a limited effect under plane strain conditions. The formation of residual plastic wake is responsible for a progressive increase of \(U^{*}\) towards a stabilized value, after which a slow but steady increase is observed. The long stabilization of the closure values means that in many cases it occupies a significant part of the notch affected zone. The level of crack closure is defined by two opposite mechanisms, which are the elongation of plastic wedges behind crack tip and crack tip blunting. This complexity explains the great influence of material on crack closure level and stabilization distance. The introduction of contact in notched samples has a major effect on plastic CTOD. The decrease of notch radius produces a significant increase of crack closure phenomenon, which apparently attenuates the effect of notch radius and reduces the zone affected by the notch;  
After the notch affected zone there is a linear increase of \(\delta_{p}\) with \(\Delta a\), linked to the increase of crack tip stress fields. This effect is clearly observed in unnotched cracked specimens without contact of crack flanks. The slope of the linear variation increases linearly with \(\delta_{p}\).  
Figure 13 shows the size of plastic zone size ahead of the notch in uncracked specimens. The plastic zones are larger for plane stress conditions than for plane strain, but are always smaller than 1 mm. The plastic deformation zones extend ahead of initial crack size; therefore, the cracks propagate in plastically deformed material. However, the plastic deformation level is small having a maximum value of 0.93%. Note that the relation between the maximum remote stress and the yield stress is 33.6% for the AA6082-T6 and 11.9% for the AA7050-T6. Naturally, the increase of load level would increase the size of plastic zones and the level of plastic deformation.