esa-sceva/satcom-chunk-collection huggingface dataset:
###### Abstract  
In this study, several wall painting fragments discovered in the Roman baths from the archeological site Alburnus Maior (Rosja Montana, Romania) were analyzed with the aim to investigate the material composition of both plasters and pictorial layers. Dated from the beginning of the second century AD, these rare findings stand among the oldest examples of preserved decorative polychrome paintings on plaster excavated thus far in the former territory of the Roman province of Dacia. A non-destructive multi-analytical approach based on complementary techniques was considered: Fourier transform infrared (FTIR) spectroscopy, X-ray fluorescence (XRF), X-ray diffraction (XRD), UV fluorescence, and hyperspectral imaging (HSI). The obtained results highlight a common Roman color palette mainly based on naturally occurring earth pigments. Red ochre, yellow ochre, manganese-rich ochres/wads, carbon black, and calcite were identified. A traditional two-layer sequence of plasters was found--_arricio_ (based on lime and siliceous sands), and _intonaco_ (pure lime). The presence of an organic protein binder, identified via FTIR analysis, and sustained by combined imaging documentation, indicates that the pigments were applied _a seco_. The obtained results are discussed in relation to previous published data, and they can be considered as valuable archeological indicators that contribute to the understanding of the painting techniques and the materials used in the Roman provinces.  
Roman wall paintings; Roman baths; FTIR; XRF; XRD; hyperspectral imaging; pigments; ochres; Alburnus Maior; cultural heritage +
Footnote †: journal: Applied Sciences
# RF-EMF Exposure near 5G NR Small Cells
## 4 Discussion and Conclusions
Furthermore, the results of this work can be used by, e.g., electric utilities who are considering placing 5G small cells on poles or other utility infrastructure in neighborhoods. In communicating with the public about this possibility, it is helpful if utilities are shown to be proactive in research on RF exposure. Furthermore, inquiries about possible RF exposure can be answered with more confidence (even though the particular situations might be different) if measured exposure levels are available. The maximum exposure levels reported here are generally applicable at other sites. As they are directly dependent on the power of the base station, they can easily be scaled to the base station powers at these sites. For example, for the E10 base station class [2; 3], the 10 dB (i.e., tenfold) decrease in maximum power compared to E100 (Table 1) would result in maximum exposure ratios of 0.02 (occupational) and 0.07 (general public). Furthermore, the results of the E100 base station at site #2 should be valid at any site with a passive antenna with the same antenna gain. Finally, due to their physical properties (larger available bandwidth, smaller antenna arrays, and the fact that small cells would be in the line of sight of many users anyway), the use of millimeter waves (\"mmWaves\"), with frequencies above 24 GHz, may be preferred for 5G NR small cells, compared to the sub-6 GHz frequencies. However, due to the availability of sites for the study duration, for this paper only 5G NR signals at sub-6 GHz frequencies were considered. Future work will consist of analyzing the exposure levels of small cells operating at much higher frequencies (e.g., 26 GHz), using similar methods as described in this paper (with settings adjusted according to the different frequency, bandwidth, and signal structure) and discussed in [14; 15; 16]. Conceptualization, S.A., R.G.O., W.J., P.T. and L.M. ; methodology, S.A., K.D. and L.V. ; software, S.A., K.D. and L.V. ; formal analysis, S.A.; investigation, S.A., K.D. and L.V. ; resources, W.J. ; data curation, S.A.; writing--original draft preparation, S.A.; writing--review and editing, S.A., K.D., L.V., R.G.O., P.T. and W.J. ; visualization, S.A.; supervision, R.G.O., L.M., P.T. and W.J. ; project administration, P.T. ; funding acquisition, S.A., W.J. and L.M. All authors have read and agreed to the published version of the manuscript. This research was funded by the Electric Power Research Institute (EPRI), grant agreement 10013613. The data presented in this study are available on request from the corresponding author. The authors would like to thank [PERSON] and [PERSON] for reviewing the study results. The authors declare no conflict of interest.
## 2 Theory
### The Cause of Branch Ambiguity
#### 2.1.1 Surmounting the Branch Ambiguity Issue: Kramers-Kronig Relations  
Since the effective dielectric permittivity \(e_{eff}(\omega)\) and the effective magnetic permeability \(\mu_{eff}(\omega)\) of an MM must be causal quantities [29; 33], we have it that their real and imaginary parts must obey Kramers-Kronig (K-K) relations [29; 33]. This result suggests a way to overcome the lack of uniqueness afflicting Equation (2). The rationale can be outlined as follows: because of causality, we have it that the effective complex refraction index, \(N_{eff}(\omega)=\sqrt{e_{eff}(\omega)\mu_{eff}(\omega)}\), must be analytic on the complex upper plane \(\mathbb{C}^{\dagger}\), with no zeros on this region [29; 33]. This fact allows relating the real and the imaginary part of \(N_{eff}(\omega)\) via K-K relations. More precisely, since the term \(\kappa_{eff}(\omega)\) is uniquely determined from relation (3), it allows \(n_{eff}(\omega)\) to be expressed as follows:  
\[n_{eff}(\omega)=1+\frac{2}{\pi}\mathcal{P}\int_{0}^{+\infty}\frac{\omega^{ \prime}\kappa_{eff}(\omega^{\prime})}{\omega^{\prime 2}-\omega^{2}}d\omega^{\prime} \tag{4}\]  
from which \(n_{eff}(\omega)\) can be computed without any ambiguity [30; 33]. Exploiting the intimate relationship between K-K relations and the _Hilbert transform:_\(\mathcal{H}[\cdot]\)  
\[\mathcal{H}[\cdot]=\frac{1}{\pi}\mathcal{P}\int_{-\infty}^{+\infty}\frac{[ \cdot]}{\omega-\omega^{\prime}}d\omega^{\prime} \tag{5}\]  
it is possible to rewrite relation (4) as follows [29; 34].  
\[\mathsf{Re}[N_{eff}(\omega)]=1-\mathcal{H}\left[\mathsf{Im}[N_{eff}(\omega)]\right] \tag{6}\]
# Circulating Current Reduction in MMC-HVDC System Using Average Model
## 1 Introduction
In another approach, differential current controllers were used to control capacitor voltage fluctuations, which increases the hardware burden on system as well as additional controller specific adjustments. 4. However, in this research work, a new method is proposed to minimize capacitor energy variations by injecting even order harmonics to the upper and lower arm currents, which restricts excessive negative currents in each arm of the MMC, leading to the presence of DC current components. This also results in the reduction of circulating currents and RMS values of the arm current inside each leg of the MMC, which is evident from analytical and simulation results reported in this paper. 5. The proposed method is implemented on a point-to-point MMC-HVDC test system based on a non-linear AVM model using the vector current control method. Section 2 describes the MMC-HVDC system topology and its operational principle, and Section 3 explains the control system design of the MMC-HVDC system. The development of the AVM model is presented in Section 4. In Section 5, voltage references are derived based on direct and proposed direct modulation methods along with the flow chart of the proposed method. Section 6 presents analytical and simulations results by comparing capacitor energy variations using the traditional direct modulation method and the effect of 2 nd and 4 th harmonics on capacitor energy variations, which validates the accuracy of the proposed method. Finally, conclusions are drawn in Section 7.
# Low-Cost IoT Air Quality Monitoring Station Using Cloud Platform and Blockchain Technology
## 3 Methodology
### ThingSpeak  
ThingSpeak is a web-based open-source platform designed for Internet of Things (IoT) applications [21]. It enables users to gather, analyze, and visualize data from different types of IoT devices, sensors, and applications in real time. It provides a great, well-organized platform for management and good tools to analyze data generated by the connected devices. It is also equipped with a great user-friendly graphical user interface (GUI).
# Deploying Secure Distributed Systems: Comparative Analysis of GNS3 and SEED Internet Emulator
## 6 Results and Evaluation
### Cost Evaluation  
In this subsection, we provide quantitative results based on an estimated price range for Small- and Medium-sized Enterprises (SMEs) to plan their network architecture strategy, adopting an emulated and hybrid architecture.  
The cost analysis (Table 1 in Appendix A) compares the network emulation and physical architectures using physical Cisco devices and the GNS3 platform. It is important to note that prices can change over time and are subject to various factors such as the vendor, model, and time of purchase. Our considerations were based on reasonable business application needs for a network similar to the one considered in this paper. Due to financial constraints, we implemented the network using second-hand devices. Comparing physical network architectures is challenging due to the many models, use cases, and time factors involved. For this comparison, we considered new state-of-the-art devices with prices taken from Amazon (U.K.) in November 2022.  
In this comparison, the main component of network emulation was the host server (see Table 2 for the detailed configuration), which included two 22-core CPUs with 64 GB of RAM. Theoretically, the network emulation can support up to approximately 35 networking devices, allowing each device one logical core and 1-2 GB of RAM depending on the device's needs. This allows for significant scalability at a total maximum cost of GBP 2899. In contrast, the price for the physical Cisco equipment is GBP 4461. This cost comparison showed that purchasing and deploying the physical Cisco network architecture is significantly more expensive than an emulation solution such as GNS3 and Cisco CLM in this study. One of the most-impactful conclusions from the table is that physical devices are priced for a single item, unlike the Cisco CLM, which provides unlimited devices as long as the host server can provide the resources needed for emulation. This demonstrates a more-scalable and cost-effective solution for SMEs.
## 4 Performance Evaluation
### Simulation Environment  
The proposed SensorAnt scheme is simulated by deploying different sensor nodes from 10 to 100 based on five different fields to reflect different sensor nodes density--200 \(\times\) 200 m\({}^{2}\) for 10 sensor nodes, 300 \(\times\) 300 m\({}^{2}\) for 20 sensor nodes, 400 \(\times\) 400 m\({}^{2}\) for 30 sensor nodes, 500 \(\times\) 500 m\({}^{2}\) for 40 sensor nodes and 600 \(\times\) 600 m\({}^{2}\) for 50, 60, 70, 80, 90 and 100 respectively. Figure 6 describes the network model which is flat topology based for one scenario used in this paper. The figure represents the snapshots from the QualNet it contains 100 sensor nodes deployed randomly in the field area 600 \(\times\) 600 m\({}^{2}\). All the sensor nodes have the same characteristics and operated with identical battery power. The blue links in the figure indicate to the wireless link that connected all the nodes to subnet (network field). While the green links indicate to the messages exchange during the simulation run time inside the sensor network, and the green numbers indicate to the sensor identification (sensor-ID).  
The other parameters used in our simulation are listed in the Table 1. The results of SensorAnt scheme are compared with Energy Efficient Ant-Based Routing (EEABR). In addition, to be more objective we have re-implemented the EEABR routing protocol to work in QualNet libraries in order to run both methods under the same simulator with similar software and hardware platforms. We then tested and validated our SensorAnt method under the same scenarios and simulation setting used by EEABR, in order to prove the effectiveness of our method.  
Figure 6: The network model for 100 sensor nodes in flat topology.
# A Review of Double-Walled and Triple-Walled Carbon Nanotube Synthesis and Applications
## 3 Synthesis and Characterization of TWNTs
[148] achieved the selective growth of TWNTs by means of a newly-developed radiation-heated catalytic chemical vapor deposition (CCVD) method. As mentioned before, the number of walls of CNTs varies sensitively depending on the metal catalyst particle diameter. Therefore, to achieve selective growth of DWNTs or TWNTs, a narrow catalyst diameter distribution is important. The thin film of catalyst metal nanoparticles with a narrow diameter distribution was prepared by dip-coating precursor solution onto a quartz glass [148]. The diameter distribution was well controlled by optimizing the concentration of the Co and Mo precursors, which was varied from 0.01-0.10 wt % in an ethanol solution in this study [148]. The catalyst nanoparticles where prepared on a Si substrate and were heated rapidly by infrared irradiation. This rapid heating process suppressed the effect of aggregation, and thus, the diameter distribution of metal nanoparticles remained narrow, which also improved the selectivity of the number of walls. SWNTs, DWNTs and TWNTs were selectively grown on the substrate prepared from 0.01, 0.03 and 0.07 wt % precursor solution respectively, and this selectivity for optimizing the conditions was reported to be 100% (SWNTs), 88% (DWNTs) and 76% (TWNTs), respectively, without any purification process. They also tried to grow wall number-selected CNTs by the conventional CVD techniques. However, the diameter distribution was widened during the heating process in the case of the conventional CVD method; therefore, the SWNTs were also grown predominantly using this technique [148]. The effective catalyst size for the SWNTs, DWNTs and TWNTs thus produced were found to be 2-8 nm, 8-11 nm and 11-15 nm, respectively [148]. The authors claim that the layer numbers of CNTs can be precisely controlled by control of the diameter, thickness or active area of the metal catalyst [148]. However, an increase of the diameter or the film thickness of the metal catalyst usually enlarges the diameter of the inner-most tube of the CNTs as a side effect, so that it is difficult to synthesize TWNTs with the inner-most tube remaining small. Although CNTs lose their quantum effects with increasing diameter, the other synthesis route of TWNTs has also been explored, as they still present very interesting mechanical properties [2; 148].
## 4 Simulation
### Data Traffic Overhead  
To evaluate the traffic overhead of the protocols, we use the number of data messages generated per second, which is a summation of individual message-hops [20]. For example, if a data message is forwarded five hops, the message overhead is counted as five message-hops. From Figure 6, we can see the number of messages generated by each of the four protocols increases as the data generation rate increases. However, the increase trends are very different from each other. The overhead of the epidemic protocol increases fastest among all protocols, and the traffic overhead of FAD is obviously higher than that of DRADG and Spray-and-Wait, which means FAD generates too many messages copies though it achieves high data delivery ratio. Due to its effective reduction of the number of message copies and proper selection of next hop nodes, we can clearly find that the traffic overhead of DRADG is the lowest in the four protocols.  
Figure 5: Impact of node density. **(a)** Average delivery ratio; **(b)** Average delay.
# Fast Coherent Video Style Transfer via Flow Errors Reduction
## 5 Experiments
### Quantitative Evaluation  
We verified our method on the MPI Sintel dataset [66] and Davis 2017 dataset [68], and tested our approach on more than 40 videos including animation and real-world videos. To fairly evaluate the performance of different approaches, we adopted two metrics to assess the transferred videos on stylization effects and temporal consistency. Here, the SIFID score is adopted to measure the style distribution distance between the generated image and its style input. And a lower SIFID value indicates the closer style distribution of a pair. In addition, the stability error is adopted to measure temporal consistency, and a lower stability error value indicates the better temporal consistency. In this section, we firstly detail the ablation studies for image sharpness, temporal consistency and proposed mask techniques in initialization to verify our Sharpness Loss, Coherent Losses and initialization. Then, we quantitatively compare our method with state-of-the-art methods ([10; 13; 30; 35; 36; 38; 62]) by using the term _stability error_\(e_{stab}\) which calculates the temporal errors between pairs of adjacent frames in an output video. The _stability error_\(e_{stab}\) is defined as:  
\[e_{stab}=\sqrt{\frac{1}{(N-1)\times D}\sum_{t=2}^{N}\sum_{i=1}^{D}m_{i}^{t}(x_{ i}^{t}-u_{i}^{t})^{2}} \tag{12}\]  
where N denotes the total frame number of a video output, D denotes the total number of pixels in one video frame and \(m^{t}\) denotes the per-pixel flow weight. This formulation is similar to Equation (6), except that we sum up all the temporal loss for pairs of consecutive frames in a video. The warped image \(w^{t}\) warps the \(=x_{out}^{t-1}\) at \(t-1\) which is time forward to \(t\). The ground truth of optical flow and flow weight can be obtained from Flownet2 [63] or the MPI Sintel dataset [66].
## 3 Results and Discussion
### Experimental Results
In Figure 6a, the range from 23 to 32 \({}^{\circ}\)C is used, while, in Figure 6b, temperature varies between 47 and 52 \({}^{\circ}\)C. Taking into account the demonstrated temperature influence on thermal conductivity, data from the literature were retrieved by selecting temperatures as close as possible to the present experimental values. In addition to these criteria, the closest possible nanoparticle sizes were chosen. In this case, nanoparticles sizes from the literature were in the range from 10 to 20 nm, while 15 nm were used in the present research. As the literature demonstrates, for example [25], a strong effect of particle size reduction on the enhancement of the thermal conductivity of alumina-water nanofluid was observed. This can be related to the higher specific surface obtained using smaller size nanoparticles, as shown by [35]. From Figure 6, it can be observed that a high dispersion of thermal conductivity data exists, evenly using the same nanoparticle volume fraction and close temperatures and nanoparticle sizes. For both temperatures evaluated, thermal conductivities obtained in the present experimental work are near to the results reported by [14; 21; 32]. The volume fraction dependence of thermal conductivity seems to be approximately similar in these cases. Observing the summary presented in Table 1, it can be seen that the phase of the nanoparticle used in these studies was not specified. The rest of the studies shown in Figure 6 report a much higher increase in thermal conductivity with the nanoparticle volume fraction. In particular, purple and red curves [24; 26] show larger slopes. This performance could be associated with the nanoparticle phase used in these experiments, corresponding to the gamma-phase, as shown in Table 1. In the rest of the experiments shown in the figure, the phase was not specified. The linear trend of curves in Figure 6 indicates a direct relationship between nanoparticle concentration and nanofluid thermal conductivity. This performance is valid when the type of nanoparticle and the nanofluid temperature remain constant and, also, when a good dispersion of nanoparticles occurs in the base fluid. In other conditions, the dependence between concentration and thermal conductivity is modified.
###### Abstract  
With the advancement in next-generation communication technologies, the so-called Tactile Internet is getting more attention due to its smart applications, such as haptic-enabled teleoperation systems. The stringent requirements such as delay, jitter, and packet loss of these delay-sensitive and loss-intolerant applications make it more challenging to ensure the Quality of Service (QoS) and Quality of Experience (QoE). In this regard, different haptic codec and control schemes were proposed for QoS and QoE provisioning in the Tactile Internet. However, they maximize the QoE while degrading the system's stability under varying delays and high packet rates. In this paper, we present a reinforcement learning-based Intelligent Tactile Edge (ITE) framework to ensure both transparency and stability of teleoperation systems with high packet rates and variable time delay communication networks. The proposed ITE first estimates the network challenges, including communication delay, jitter, and packet loss, and then utilizes a Q-learning algorithm to select the optimal haptic codec scheme to reduce network load. The proposed framework aims to explore the optimal relationship between QoS and QoE parameters and make the tradeoff between stability and transparency during teleoperations. The simulation result indicates that the proposed strategy chooses the optimal scheme under different network impairments corresponding to the congestion level in the communication network while improving the QoS and maximizing the QoE. The end-to-end performance of throughput (1.5 Mbps) and average RTT (70 ms) during haptic communication is achieved with a learning rate and discounted factor value of 0.5 and 0.8, respectively. The results indicate that the communication system can successfully achieve the QoS and QoE requirements by employing the proposed ITE framework.  
Keywords:5G; URLLC; tactile Internet; IoT; codecs; RL +
Footnote †: journal:
## 2 VR Applications  
### Holograms over Proposed System  
To increase the application effectiveness, augmented reality and virtual reality are increasingly used in conjunction with other technologies, for example, with the Internet of things applications, Tactile Internet and holographic telepresence [23; 24; 25; 26]. The holographic presence makes AR/VR more spectacular for the user and allows to see virtual holograms, which are volumetric color images. Modern equipment allows you to create practical holograms not different from real things. Including such an effect is achieved due to accurate tracking of the user's position in a given space and depending on his location playing him a stereoscopic image. AR/VR technologies allow us to project static or animated objects into real environments, thereby expanding the physical world. Earlier designs of holograms for AR are based on so-called displays in the air, sometimes also called displays in free space. Projected graphic objects are displayed in the air on free projection surfaces, such as a poorly visible fog wall or fog screen created by an installed fan [27]. One of the most popular is the Hololens equipment from Microsoft [28]. Since both Microsoft HoloLens and AR glasses are capable of tracking head movements, they create the impression of a constant presence of holographic geospatial objects in the user's environment. Even if the user walks in a certain area, usually indoors, the holograms remain and adapt to the user's location and viewing perspective. This constant and adaptable holographic projection can lead to visualization approaches that bring additional benefits for cognitive processing. Presented as the first stand-alone holographic computer, Hololens unites the physical and digital worlds, allows users to interact with digital content and interact with holograms in mixed reality. The work [29] is devoted to a technical assessment of the use of Hololens for multimedia applications.