esa-sceva/satcom-chunk-collection huggingface dataset:
# Experimental Study of Radiated Emission Due to Secondary Common-Mode Current in Buck Converters
## 4 Noise Measurements in the Experimental System
### Radiated Emission  
Radiated emission from the experimental system was measured in a semi-anechoic chamber. Figure 13 shows a picture of the experimental setup for radiated emission measurements. The experimental system has the same configuration and layout as the setup for the CM current measurement. As shown in Figure 2, the buck converter and the load are housed in the metal box to prevent radiated emission from the power converter itself. The three-core power cable is placed perpendicular to the ground plane, and the electrical field intensity is measured with a log-periodic antenna 3 m away from the cable.  
Figure 11: Measured secondary common-mode currents.  
In this experimental setup, the vertical polarization dominates the radiated emission from the cable. Thus, this subsection evaluates only the vertical polarization.  
Figure 14 shows the measured results of radiated emission. Every measurement was performed in the frequency range from 30 MHz to 300 MHz when no CMI was connected; the P-CMI was connected; and the S-CMI was connected near the power converter. Note that the background noise was measured when only the cooling fan was operating.  
Figure 14 shows that the measured radiated emission indicates a similar tendency to the measured result of the SCM current shown in Figure 11. This result clarifies that the SCM current is the dominant source of radiated emission in the experimental system. It can be confirmed from Figure 14 that the radiated emission is suppressed to almost the background noise level when the P-CMI is connected. As described in Section 3, the PCM current and unbalance of the power supply side impedances generate the SCM voltage. The SCM voltage is suppressed because the P-CMI reduces the PCM current effectively. Thus, the connection of the P-CMI can suppress the radiated emission from the cable.  
When the S-CMI is connected near the power converter, the significant radiated emissions are measured at around 45 MHz and 110 MHz, where the large SCM current is observed in Figure 11. This result indicates that the S-CMI connected near the power converter cannot suppress the radiated noise significantly at frequencies where the SCM current is the node at the power converter side. On the other hand, the measured radiated emission is almost equal to the background noise at other frequencies. These results correlate very well with the measured result of the SCM current, as shown in Figure 11, and demonstrate the generation mechanism of radiated emission described in Section 4.1.  
Figure 12: Configuration of a monopole antenna constructed when the S-CMI is connected to the three-core cable.  
Figure 14: Measured radiated emission.  
Figure 13: Experimental setup for measurement of radiated emission in an anechoic chamber.
# Research on the Flight Performance of Biomimetic Moth Based on Flapping Function Control
## 3 Calculation and Simulation
### Simulation of the Impact of Key Parameters on the Performance of Flapping-Wing Aircraft
#### 3.2.3 Impact of Flapping Frequency of Flapping Function on Lift  
As can be seen from the lift calculation formula, under the same flapping amplitude and mid-position angle conditions, the greater the flapping frequency, the greater the lift generated. To verify the impact of flapping frequency on aerodynamic performance, three groups of flapping functions are designed, simulated, and calculated. The control parameters of the right-wing flapping function are shown in Table 5, and the left-wing flapping function is opposite to the right wing.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter** & **Flapping Motion with a 30\({}^{\circ}\)** & **Flapping Motion with a 40\({}^{\circ}\) Flapping Amplitude** & **Flapping Motion with a 50\({}^{\circ}\) Flapping Amplitude** \\ \hline \(\phi_{max}\) & \(\pi/6\) & \(2\pi/9\) & \(5\pi/18\) \\ \(T_{1}\) & 0.15 & 0.15 & 0.15 \\ \(T_{2}\) & 0.1 & 0.1 & 0.1 \\ \(\varphi_{1}\) & \(\pi/2\) & \(\pi/2\) & \(\pi/2\) \\ \(\varphi_{2}\) & 0 & 0 & 0 \\ \(\phi_{0}\) & \(\pi/18\) & \(\pi/18\) & \(\pi/18\) \\ \(T\) & 0.25 & 0.25 & 0.25 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Control parameters of flapping motion with different flapping amplitude.  
Figure 6: The impact of flapping amplitude on lift.  
The simulation time is set to 1 s, including 3-5 flapping cycles. The simulation data is imported into the software Origin_2021, and the lift curves of the three flapping motions over time are drawn, as shown in Figure 7. It can be seen that the frequency of flapping motion has a significant impact on aerodynamic performance. The average lift within a period is calculated (all in the second flapping cycle). The average lift generated by the flapping motion with a flapping frequency of 3 Hz within a period is about 0.674 N. The average lift of the flapping motion with a flapping frequency of 4 Hz is about 0.782 N; the average lift of the flapping motion with a flapping frequency of 5 Hz is about 0.836 N. Therefore, it can be concluded that increasing the flapping frequency can improve the aerodynamic performance of the flapping motion. This is consistent with the results of mathematical modeling analysis.
# A Testbed for GNSS-Based Positioning and Navigation Technologies in Smart Cities:
## 7 Conclusions
Furthermore, improved algorithms are expected to be implemented regarding snapshot processing, Wi-FiTM ranging, and CP and additional GNSS technologies deserve to be integrated in the future release of the HANSEL _testbed_. The _testbed_ could host future technologies and it can be easily cloned to support on-field test campaigns for innovative solutions to positioning and navigation in Smart Cities. A natural follow-up of the project could address the autonomous guidance within a smart city environment as approached by the proposed CAC service, by gathering new ground-breaking PNT technologies specifically supporting autonomous mobility in urban scenarios. Conceptualization, A.M., F.D., A.V., M.G.-F., A.L.-C., J.L.T., M.M., A.P.-C., G.S.-G. and J.A.L.-S.; Data curation, A.M., M.G.-F., J.G.-F. and J.A.L.-S.; Formal analysis, A.M., M.G.-F., A.L.-C. and J.G.-F.; Funding acquisition, M.G.-F. and J.A.L.-S.; Investigation, A.M., M.G.-F., G.S.-G. and J.A.L.-S.; Methodology, A.M., M.G.-F., A.L.-C., A.P.-C. and J.A.L.-S.; Project administration, F.D., M.G.F., M.M. and J.A.L.-S.; Resources, A.L.-C., Software, A.M., A.L.-C., J.L.T., A.P.-C., J.G.-F. and J.A.L.-S.; Supervision, M.G.-F., A.L.-C. and G.S.-G.; Validation, A.L.-C.; Visualization, A.M. and M.M.M. ; Writing--original draft, A.M., F.D., A.V., M.G.-F., A.L.-C., J.L.T., M.M., A.P.-C., J.G.-F. and J.A.L.-S.; Writing--review & editing, A.M., F.D., M.G.-F., A.L.-C., M.M. and J.A.L.-S. All authors have read and agreed to the published version of the manuscript. The _testbed_ presented in this paper was designed, developed and tested in the context of HANSEL (ESA ITT number AO/1-9494/18/NL/CRS), a project founded by the European Space Agency (ESA) and led by Rokubun S.L. The authors acknowledge ESA, the Project Officer, [PERSON], and all partners of the HANSEL consortium. The _testbed_ presented in this paper was designed, developed, and tested in the context of HANSEL, an ESA funded Technology Research Programme (TRP) activity. The authors would like to acknowledge European Space Agency (ESA) and all the partners of the HANSEL consortium. The authors declare no conflict of interest. The content of the present article reflects solely the authors' view and by no means represents the official view of the European Space Agency (ESA). In any reproduction of this article there should not be any suggestion that ESA or this article endorse any specific organisation or products. The use of the ESA logo is not permitted. This notice should be preserved along with the article's original URL.
# 5G New Radio Open Radio Access Network Implementation in Brazil: Review and Cost Assessment
## 4 Challenges and Opportunities in Implementing 5G NR Open RAN in Brazil
### Challenges
#### 4.1.2 Economic Challenges  
The 5G NR aims to boost MNOs profits by providing more extensive data services. High-speed services are appealing to users, including new services such as augmented reality or virtual reality (AR/VR) and QoS Service Level Agreement (SLA) [42].  
The sum among the MNOs, Claro, Vivo, and TIM, was approximately BRL 121 billion in 2023, which is 8.5% higher than in the previous year. The year before was the year of the largest percent growth. TIM had BRL 23.83 billion, which is 10.7%. The significant growth between the MNOs was Vivo's BRL 52.1 billion, which was 8.4%, and Claro's BRL 45.6 billion, which was 7.41% higher [43].  
In Latin America, the profit from the 5G implementation is projected to reach around USD 60 billion by 2030, which represents about 0.9% of the region's Gross Domestic Product (GDP). This technology will drive greater digitalization and significant economic growth. The benefits of 5G include improved health access, education, advancements in the manufacturing industry, and faster response times for public security services, traffic, and pollution control.  
Adopting Open RAN is already in demand, as the new solutions require networks that can accommodate dense device connections and low latency. Moreover, CAPEX investment to expand coverage may prioritize mMIMO for enhanced spectral efficiency and reach, reducing transmission power consumption. Energy costs make up 20 to 40% of an MNO's OPEX. The new RUs have features that enable Artificial Intelligence (AI) to regulate power usage at a cell site, such as beamforming, thus reducing the company's power expenses.  
It is worth noting that Brazilian companies may see limited benefits from open technology. Large multinational companies with operations in the country will likely attract more investments. Domestic manufacturers could be an incentive to acquire expertise and develop competitive products, transforming their national standing from followers to technology leaders. Brazilian companies often face challenges in accessing affordable capital for long-term investments. This can be particularly problematic for o-RAN technology development's high risk-high reward nature.  
The main economic challenges are as follows:  
* **Performance trade-off--**Quality and equipment cost in return for the end user's better rates and service excellence.
* **Integration costs--** Interoperability configurations and adaptation cost to workability.
* **Lack of knowledge/experience --** Network deployment and configuration require high expertise in managing and preparing the network. In some cases, the cost of failure can make the project impracticable and waste resources, time, and equipment.
# A Transformer-Based Approach for Efficient Geometric Feature Extraction from Vector Shape Data
## 3 Experiments
### Data Preprocessing  
The data preprocessing consisted of two main steps: simplification and augmentation. In the simplification step, the Douglas-Peucker methods [51] were primarily employed to simplify the original polygon outlines without imposing any point limits. Following the serialization operation described in Section 2.1, all training and test sets for the experiment were generated. In the data augmentation step, only general data augmentation techniques were used, including affine transformation, displacement, interpolation points, and rotation.
# Motion, Static Force, and Efficiency Analysis of Planetary Gear Transmission Based on Graph Theory
###### Abstract  
This paper employs graph theory to analyze kinematic relationships, static force, and power flow for planetary gear systems. We start from the graphs of these trains to determine all the structurally distinct kinematic inversions. We then obtain all the constructive solutions resulting from every possible combination of gear configuration. Based on the kinematic and static force analysis model, related matrices are acquired. Hence, a kinematic and static force analysis of the planetary gear mechanism is achieved. The link power can be determined by the link speed and torque. Power flow diagrams of each gear are acquired. The efficiency is calculated by the transmission ratio method. This analysis is useful in the design of power transmission applications. A planetary gear system of a 6 HP26 automatic transmission is further illustrated for the motion, static force, and efficiency calculations by using graph theory technique and matrix equations. This paper provides a guide for engineers in gear transmission fields to easily finish mechanical transmission design.  
planetary gear transmission; graph theory; kinematic and static force analysis; power flow and efficiency analysis +
Footnote †: journal: Applied sciences
# Evaluation of Green Strategies for Prolonging the Lifespan of Linear Wireless Sensor Networks
## 4 Energy Conservation Techniques
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Energy-Saving Techniques** & **Key Parameters** & **Pros** & **Cons** & **Impact in LWSN** \\ \hline Data Compression [74] & Compression ratio, computational load, and transmission power. & Lowers the energy cost of transmission by reducing the amount of data sent and decreasing bandwidth usage. & Compression may increase computational complexity, leading to higher processing power consumption. & More efficient in terms of energy consumption because of the simplified data flow and fewer nodes handling data aggregation tasks. The linear topology ensures that data are passed along a single path, reducing the need for re-compression or handling redundant data. \\ \hline Data Prediction [75] & Prediction models and computational power. & Reduced data transmission cost. & Ineffective in highly dynamic environments with unpredictable data patterns, potential inaccuracies in prediction, complexity of model training & Effective in LWSN when monitoring environments where data trends are predictable, reducing transmission costs. \\ \hline Edge Computing [21, 76] & Local processing power and data transmission distances. & Reduces energy used for transmitting data over long distances. & Increases computational energy at the node level. & Beneficial in LWSN as nodes can process data locally, minimizing long-distance transmissions via multi-hop communications in the linear path. \\ \hline Hierarchical Sensing [77, 78] & Sensor accuracy and power consumption. & Reduced energy consumption by frequently using low-power sensors monitoring when events of interest have not occurred. & Complexity in coordinating sensors with different capabilities. & Similar effect as in traditional WSN. More effective when combined with other techniques. \\ \hline Adaptive Sampling [79] & Sampling rate, environmental monitoring sensitivity, and node synchronization. & Reduces unnecessary data collection and energy consumption by only sampling when necessary. & May miss critical events due to infrequent sampling. requires effective prediction or detection mechanisms. & Highly effective in LWSN for conserving energy when monitoring uniform conditions, but risks losing important data in event-driven applications. \\ \hline Model-Based Active Sensing [80] & Model accuracy and event prediction capability. & Reduced sensor activation, minimized energy consumption. & Model accuracy is critical; incorrect predictions may lead to energy waste or missed events. & Highly effective in LWSN for long-term monitoring scenarios with predictable environmental conditions. \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._
# CSEM Optimization Using the Correspondence Principle
## 1 Introduction  
The controlled source electromagnetic method (CSEM) is a consolidated method in the off-shore industry [1; 2]. It is used not only to reduce the exploratory risk [3], helping to decide well placement, but also in applications aimed at reservoir monitoring [4; 5], given the significant role of electrical resistivity in characterizing rock porosity and fluid saturation.  
Based on measurements of the electric and magnetic fields made by receivers on the seabed (while a ship towed the submerged electromagnetic source), CSEM allows for obtaining a model of electrical conductivity in the subsurface through an inversion process, which iteratively minimizes the misfit between observed and modeled data.  
Several possible approaches exist to perform forward modeling in the context of the inversion of CSEM data [6]. Some of these approaches are based on solving [PERSON]'s equations for conductive media directly in the frequency domain and require solving a linear system for each frequency. Furthermore, the Gauss-Newton approximation for the model update is common during inverse problem iterations [7; 8], which usually requiresolving large linear systems, especially in 3D problems. Another critical aspect of CSEM inversion is the regularization strategy applied to stabilize the iterative process [9; 10; 11; 12]. We propose modeling CSEM data through the numerical time-domain finite-difference solution of [PERSON]'s equations for a fictitious dielectric medium, following the prescription of [13]. The correspondence principle allows the evaluation of the fields for the corresponding conductive medium in the frequency domain [14]. In the context of inversion, we present the formulation for gradient calculation, obtained using the adjoint-state method [15; 16], based on adjoint modeling following the same formulation as the forward modeling. This is the approach presented by [17] but with the correction to the equations that define the mapping between the fictitious and diffusive domains. To stabilize the inverse problem, we use model reparameterization smoothing [18; 19], which does not require trial-and-error selection of a regularization parameter.  
We also evaluate two optimization algorithms: the steepest descent (using a simple line search strategy) and a momentum method [20], parameterized according to the Adam algorithm [21], known as a low memory demand method. We also compared the results with those obtained using L-BFGS-B [22; 23], which is traditionally used in minimization problems. Our numerical experiments show that both algorithms successfully fit the observations and correctly localize the inversion targets, but our momentum approach has low storage demand.
## 4 Discussion
The result of the nonlinear response of the composite probe used in our system, which is shown in Figure 8, indicates that the frequency response changed with the intensity of the photoacoustic wave due to the nonlinearity of the composite probe. This nonlinearity might enhance the change in the frequency responses shown in Figures 5b and 7b, and therefore one can differentiate the strong photoacoustic signal of the pigmented parts from the normal parts by detecting the spectral changes. The results of photoacoustic imaging of simulated caries showed that the image of brownish hidden caries could be obtained by the proposed photoacoustic imaging system when the size of lesions are relatively large. In the photoacoustic image of the tooth sample without pigment inside, which is shown in Figure 9, no dark spot is evident, which indicates that fissures and pits on the occlusal surface do not induce photoacoustic waves sufficiently strong to be mistaken for the signal from the pigment. In the photoacoustic images of tooth samples with simulated caries lesions of different sizes, which are shown in Figure 10a,b, the contrast of the observed image was worse than that of the simulated caries at shallower depths due to the optical scattering and absorption of the thicker dental tissues. However, we confirmed that the simulated caries was observed as a dark spot at the location of the caries. Note that in Figure 10a,b the shapes of the obtained photoacoustic images do not coincide with the shapes of the fissures on the occlusal surface. This indicates that fractions and fissures do not affect the photoacoustic images. Furthermore, the size of the observed dark spot nearly coincides with that of the simulated caries when the simulated caries lesions are larger than 1.2 mm. However, no clear image was not obtained for the lesion with the size of 0.5 mm as shown in Figure 10c. As a result of photoacoustic imaging of an extracted human tooth with a real hidden caries lesion, the hidden caries with an ellipse shape was detected near the hidden caries lesion located by the CT observation, demonstrating the feasibility of the proposed method for the detection of real hidden caries. However, the shape of the dark spot in the observed photoacoustic image did not exactly coincide with the CT image. This is due to the non-uniformities in the enamel thickness and the color of real dental caries. The proposed method can only detect comparatively strong photoacoustic signals from caries with a brown color. At the present stage, therefore, the method cannot detect a demineralized area without a color change. However, this may become possible with a photoacoustic method using different polarization directions.
# A Blockchain-Based Decentralized Public Key Infrastructure Using the Web of Trust
## 7 System Evaluation and Limitations
### Cost Analysis  
Our system utilizes three specialized smart contracts, each designed for efficiency and minimal data storage to ensure cost-effectiveness. Key points include the following:  
* **Simplicity and Efficiency:** By maintaining simple contract designs and employing Solidity's features, such as utilizing bytes over strings, preferring delegatecall where possible, and using bit operations, we aim to minimize gas costs.
* **Cost Calculation:*
* **Low-Cost Operations:*
* Common tasks like request creation, signature additions, and revocations incur moderate costs.
* **Free Operations:** Operations that do not modify blockchain data, such as CSR processing and data reading, are free.
* **High-Cost Write Operations:** Functions that update blockchain data, especially storing CSR hashes and certificate metadata, are gas-intensive.  
Due to the significant expenses of certain write operations, focused cost analysis and optimization can be performed to ensure the system's efficiency and cost-effectiveness.