esa-sceva/satcom-chunk-collection huggingface dataset:
## 2 Heliostat Orientation
### Azimuth-Elevation (AE) Orientation  
To obtain the mirror center and orientation, the following procedure can be applied, assuming that the heliostat initially points upwards and that the origin is at the intersection of axis a with axis b (see Figure 2):  
Figure 1: Rotating axes, primary (\(\alpha\) angle, purple color) and secondary (\(\beta\) angle, green color), for azimuth-elevation, tilt-roll, and target-aligned mechanical designs. The 3 layouts can be described by the product of two rotating matrices, around the orthogonal x, y, z axes.  
\[\begin{bmatrix}n_{x}\\ n_{y}\\ n_{z}\end{bmatrix}=\begin{bmatrix}1&0&0\\ 0&\cos\alpha&-\sin\alpha\\ 0&\sin\alpha&\cos\alpha\end{bmatrix}\begin{bmatrix}\cos\beta&0&\sin\beta\\ 0&1&0\\ -\sin\beta&0&\cos\beta\end{bmatrix}\begin{bmatrix}0\\ 0\\ 1\end{bmatrix} \tag{4}\]
3. Using the rotating angles, \(\alpha\) and \(\beta\) and offsets, o1 and o2, recalculate the center vector, \(\overset{\rightarrow}{c}\), as follows: \[\begin{bmatrix}c_{x}\\ c_{y}\\ c_{z}\end{bmatrix}=\begin{bmatrix}1&0&0\\ 0&\cos\alpha&-\sin\alpha\\ 0&\sin\alpha&\cos\alpha\end{bmatrix}\begin{bmatrix}0\\ 0\\ 01\end{bmatrix}+\begin{bmatrix}\cos\beta&0&\sin\beta\\ 0&1&0\\ -\sin\beta&0&\cos\beta\end{bmatrix}\begin{bmatrix}0\\ 0\\ 02\end{bmatrix}\end{bmatrix}\] (5) (4) Repeat steps 1, 2, and 3 until convergence is reached for the \(\alpha\) and \(\beta\) angles and the normal and center vectors.
# UAV-Based Evaluation of Rockfall Hazard in the Cultural Heritage Area of Kipinas Monastery, Greece
## 4 Rockfall Hazard and Risk Assessment
### Rockfall Hazard and Risk Rating System
** Catchment zone obstacles & 5\% & Dense (trees and big & Moderate (small & Sparse (grass and & None \\  & **Rating** & & **10** & **30** & **60** & **100** \\ \hline \multirow{8}{*}{A.} & 7. Joint(s) orientation & & Favorable for stability & Moderate & Adverse & Very adverse \\  & **Rating** & & **10** & **30** & **60** & **100** \\  & 8. Joint(s) persistence (m) & 2\% & \textless{}2 & 2–4 & 4–8 & \textgreater{}8 \\  & **Rating** & & **10** & **30** & **60** & **100** \\  & 9. ** Strength of intact rock (MPa) & 1\% & \textless{}25 & 25–50 & 50–100 & \textgreater{}100 \\  & **Rating** & & **10** & 30 & **60** & **100** \\  & **10. ** Tensile strength (MPa) & 1\% & \textless{}2 & 2–7 & 7–12 & \textgreater{}12 \\  & **Rating** & & **10** & **30** & **60** & **100** \\  & **11. ** Rock mass structure & & & & & \\  & **Rating** & & & & & \\  & **B. ** & & & & & \\  & & & &Each examined factor can be evaluated between 10 and 100, as the conditions evolve from favorable to adverse, and then is multiplied by a respective predetermined weight. The total hazard score is calculated by summing the individual score of each factor, from the first three (A, B and C) major categories. At last, the total risk score is calculated by adding the fourth category (D) to the hazard score. Therefore, a slope with the highest hazard level will have a total weighted score of 70 and, one with the highest risk level a total weighted score of 100. The final result of this assessment is the construction of two (2) separate classifications, one hazard and one risk related, with five categories each (very low up to very high) for all four distinct sub-regions in the investigated site. Based on these classifications, both a hazard and a risk zonation of the whole investigated cliff against rockfall occurrence were made possible to be constructed. These classifications are shown in Tables 8 and 9. Lastly, it is important to highlight that the proposed rating system was developed on an empirical basis, with the involved parameters, their rating and their weight ranges based on the available data, reasonable geoengineering judgment and the known facts.
# Real-Time Identification of Look-Alike Medical Vials Using Mixed Reality-Enabled Deep Learning
## 5 Evaluation and Discussion of the Proposed Model's Results
### Model Performance Evaluation  
The proposed model demonstrates significant improvements in various evaluation metrics, as shown in Table 1. In particular, it achieves higher mAP scores, a faster inference time, and a better FPS than the YOLOv4 Tiny model.  
The proposed model outperforms YOLOv4-Tiny in both accuracy and real-time performance, achieving a higher mAP of 98.76% and a lower inference time of 20 ms. These enhancements ensure its smoother deployment in Mixed Reality applications while maintaining high detection precision.  
\begin{table}
\begin{tabular}{l c c} \hline \hline
**Metric** & **Proposed Model** & **YOLOv4 Tiny** \\ \hline
**[EMAIL_ADDRESS]** & 98.76\% & 95.19\% \\
**mAP@[0.5:0.95]** & 86.54\% & 85.72\% \\
**Precision** & 0.96 & 0.96 \\
**Recall** & 0.96 & 0.91 \\
**FI-Score** & 0.96 & 0.91 \\
**IoU** & 0.74.95\% & 69.22\% \\
**Frame per second(FPS)** & 50 & 40 \\
**Inference Time** & 20 ms & 30 ms \\ \hline \hline \end{tabular}
\end{table}
Table 1: Performance comparison between the proposed model and YOLOv4 Tiny, showing overall evaluation metrics as well as class-wise accuracy for selected vials.
## 2 Materials and Methods
### GNSS > Sonar > Phone System Implementation
#### 2.2.2 Connection Management and App Data Transfer  
In order to make the operating system and synchronise the devices described, the connections of devices and the transmission of data between apps must be organised correctly.  
The external GNSS receiver (SimpleRTK2B) was connected via USB OTG connection to the smartphone to receive power from the smartphone and transmit the GNSS-Raw data to the SW Maps app, which recorded the GNSS-Raw data for post-processing (GNSS-Raw data--Power in Figure 1). Simultaneously, the external GNSS receiver was connected via Bluetooth to the smartphone in order to transmit in real-time the GNSS SPP positioning data (GNSS-SPP data Real-time in Figure 1) to the GPS Connector app. The GPS Connector re-transmits the GNSS-SPP data Real-time to the Fish Deeper--Fishing App using the \"mock location\" function of the smartphone. Finally, the Deeper Smart Sonar was connected to the smartphone via Wi-Fi to receive the GNSS-SPP data Real-time by the Fish Deeper--Fishing App and re-transmit the GNSS-SPP data Real-time and the Sonar data to the Fish Deeper--Fishing App (GNSS-SPP Real-time + Sonar data Figure 1).  
In order to allow GPS Connector to send external GNSS positioning data to other apps, GPS Connector must be enabled via the \"mock location\" function accessible from the developer options (developer options must be unlocked depending on the type of smartphone) and via the settings of the app itself. This step is very important as it allows the real-time synchronisation between the external GNSS receiver and sonar and the subsequent synchronisation in PPK.  
To enable the sonar to geolocate itself via GNSS data received from the smartphone in the Fish Deeper--Fishing App, \"Boat\" must be selected as the fishing mode. In addition, to improve the connection between the smartphone and the sonar, Deeper UAB recommends disabling the mobile data and the settings that automatically switch between Wi-Fi and mobile data to stay online. Therefore, internet access is not available during the survey. Finally, during the experimentation with the Huawei P30 Pro, it was noted that in order to prevent GNSS positioning from being compromised by mobile and Wi-Fi networks surrounding the area to be surveyed, it would be advisable to disable the \"Google Location Accuracy--Improve Location Accuracy\" function; we do not know if this problem is also present on other smartphones.
## 4 Discussion
### Terrain Complexity  
Photogrammetric surveys in flat areas present several challenges, mainly due to the low variation in terrain elevation. This lack of relief can affect the accuracy of the 3D model, as it limits the spatial information available for the calculation of internal and external camera parameters. Consequently, estimating these parameters may become less robust, compromising the quality of the final photogrammetric product.  
The choice of an area with gentle slopes in this study responds to the objective of isolating the impact of key factors such as flight design and the distribution of control points, preventing topographic complexity from introducing interferences in the evaluation. By working on practically flat terrain, external variables that could affect the accuracy of the photogrammetric reconstruction are minimised, which is relevant when analysing the behaviour of cameras with electronic rolling shutters, which are more sensitive to geometric distortions that can be amplified by operating conditions such as flight speed, direction of travel, or the inclination of the captured images.
# State-of-the-Art DC-DC Converters for Satellite Applications: A Comprehensive Review
## 4 Comparative Analysis of Various Topologies
\begin{table}
\begin{tabular}{l c c c c c c c} \hline
**Converter** & **References** & **Figure** & **Reliability** & **Redundancy** & **Modularity** & **Power Density** & **Efficiency** \\ \hline Full-bridge converter & [96] & Figure 13a & Medium & No & No & Medium & 95 \\ Current-fed researched buck and & [96] & Figure 13b & High & No & No & Medium & 95 \\ Full-bridge converter & [96] & Figure 14a & Medium & No & No & Medium & 90-95 \\ Resonant LLC converter & [96] & Figure 14b & Medium & No & No & Medium & 95–98 \\ Conventional DAB & [104] & Figure 15a & High & No & No & Medium & High \\ ISOP-DAB & [104] & Figure 15b & High & Yes & Medium & High \\ NPC-DAB & [104] & Figure 15c & Low & No & No & Low & Low \\ ANPC-DAB & [104] & Figure 15d & Low & No & No & High & High \\ Parallel interleaved DAB & [104] & Figure 15e & High & Yes & Yes & High & - \\ ABAC converter & [67;98] & Figure 16a & Low & Yes & Yes & High & High \\ ACF converter & [110] & Figure 16b & High & Yes & Yes & High & 90-95 \\ \hline \end{tabular}
\end{table} 
Table 6: Comparison of various isolated DC-DC converters in terms of performance indicators. \begin{table}
\begin{tabular}{l c c c c c c} \hline
**Converter** & **References** & **Figure** & **Reliability** & **Redundancy** & **Modularity** & **Power Density** & **Efficiency** \\ \hline Three-port modified half-bridge converter & [38] & Figure 17b & Low & No & No & Low & High \\ Non-isolated PWM three-port converter & [37] & Figure 18a & Medium & No & No & Medium & 97.3 \\ Two-switch forward with integrated buck converter & [18] & Figure 18b & High & No & No & High & 95 \\ \hline \end{tabular}
\end{table} 
Table 7: Comparison of various integrated DC-DC converters in terms of performance indicators. Figure 20: Various performance indicators of DC-DC converters for satellite applications.
###### Abstract  
Visible light communication (VLC) has developed rapidly in recent years. VLC has the advantages of high confidentiality, low cost, etc. It could be an effective way to connect online to offline (O2O). In this paper, an RGB-LED-ID detection and recognition method based on VLC using machine learning is proposed. Different from traditional encoding and decoding VLC, we develop a new VLC system with a form of modulation and recognition. We create different features for different LEDs to make it an Optical Barcode (OBC) based on a Complementary Metal-Oxide-Semiconductor (CMOS) senor and a pulse-width modulation (PWM) method. The features are extracted using image processing and then support vector machine (SVM) and artificial neural networks (ANN) are introduced into the scheme, which are employed as a classifier. The experimental results show that the proposed method can provide a huge number of unique LED-IDs with a high LED-ID recognition rate and its performance in dark and distant conditions is significantly better than traditional Quick Response (QR) codes. This is the first time the VLC is used in the field of Internet of Things (IoT) and it is an innovative application of RGB-LED to create features. Furthermore, with the development of camera technology, the number of unique LED-IDs and the maximum identifiable distance would increase. Therefore, this scheme can be used as an effective complement to QR codes in the future.  
visible light communication (VLC); machine learning; CMOS image sensor; image processing; RGB-LED +
Footnote †: journal: Applied Physics Letters
The works mentioned above mainly considered single-objective optimization scenarios, which may be not generalized and universal for some practical MEC systems. Motivated by these facts, we propose a multi-MEC server and multi-IoT device cellular network structure and investigate a weighted sum of multiple objectives minimization optimization problem in this paper. The weighted sum of multiple objectives optimization problems in dynamic MEC systems were also studied in [19; 20; 21], but the optimization objectives and system models are different to ours. The key differences between the relevant works and our work are shown in Table 1. The main contributions of this paper are summarized as follows:1. A multi-MEC server and multi-IoT device cellular network structure is proposed. A high-cost and high-performance primary MEC server (PMS) with relative strong computing power is deployed in the BS, and multiple low-cost secondary MEC servers (SMSs) with relative weak computing powers are deployed within the coverage area of the BS. 2. An optimization problem is formulated. The problem considers the weighted sum of multiple optimization objectives, including the minimization of the weighted sum of the computing pressure on the PMS, the sum of energy consumption of the network, and the task dropping cost. The formulated problem is a nonconvex mixed integer nonlinear program (MINLP) problem, which is solved by our proposed DRL-based optimization algorithm. 3. Simulation results are presented to evaluate the performance of the proposed algorithm. The correctness and effectiveness of the proposed algorithm are demonstrated by the simulation results. The remainder of this paper is organized as follows. Section 2 presents the system model and formulates the optimization problem. The proposed DRL-based optimization algorithm is described in Section 3. The complexity and convergence analysis is given in Section 4. Simulation results are provided in Section 5. Finally, Section 6 concludes this paper.
# Three-Dimensional Elastodynamic Analysis Employing Partially Discontinuous Boundary Elements
## 5 Conclusions  
To treat the corners of body surfaces in a simple manner while restricting the number of nodes, we adopted partially discontinuous elements, which are continuous on surfaces and discontinuous between adjacent surfaces, to discretize the boundary of the model for solving the elastodynamic problems. The effects of the numerical integration scheme of the partially discontinuous element and the positions of collocation points on the stability and accuracy of the computational results were studied. We found the following:  
(1) The computational accuracy of the singular integral is sensitive to the time step. For instance, the traditional singular integration scheme cannot obtain reliable results in the case where the value of the time step adopted is small. The proposed improved singular element subdivision method takes the time step into consideration, which significantly reduces the side effect of the time step on the accuracy of the singular integral. Meanwhile, it will not introduce too many Gauss points' numbers. The proposed singular element subdivision method can improve the stability and accuracy of the dynamic response results in a short time. However, the accumulated error becomes larger and larger as the number of analysis steps increases, which leads to the rapid damping of the amplitude of the result.  
(2) The effects of the node position in the completely discontinuous element and the partially discontinuous element on the results were compared. In terms of the stability of the computation results, the partially discontinuous element has obvious advantages over the completely discontinuous element. In terms of computational accuracy, the accuracy of the results of the partially discontinuous elements is more stable than that of the completely discontinuous elements and insensitive to the node position.  
(3) When using the discontinuous element, the inward shrink ratio of the element node should be carefully determined. Otherwise, it may cause unstable results. For partially discontinuous elements, the recommended value range of the inward shrink ratio is [0.15, 0.3] in the case of adopting linear quadrilateral elements. It should be noted that the more complex the model boundary, the smaller the available range of the inward shrink ratio.  
Conceptualization, Y.L., W.M.; methodology, Y.L.; software, Y.L.; validation, Y.L., N.Z., Y.G.; formal analysis, Y.L.; data curation, N.Z., S.Z.; writing--original draft preparation, Y.L.; writing--review and editing, Y.G., W.M.; visualization, N.Z., S.Z.; project administration, Y.L.; funding acquisition, Y.L., W.M., S.Z. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China (Nos. 11702087, U1704158), and the Key Research Project of Higher School of Henan Province (No. 21A520020).  
**Data Availability Statement:** Not Applicable, the study does not report any data.  
**Conflicts of Interest:** The authors declare no conflict of interest.
# An Improved Routing Approach for Enhancing QoS Performance for D2D Communication in B5G Networks
## 5 Conclusions  
This paper presents a mobility, battery, link quality, and contention window size multicriteria-aware routing (MBLCR) approach to enhance the D2D communication over IoT-based 5G network performance. In the MBLCR approach, the mobility, battery, link quality, and contention window size of relay devices are evaluated to select the optimal route. Furthermore, an MCDM technique is employed, which provides the weights among the relay devices based on an evaluation of the relay devices' values for the selection of an optimal route among the multiple routes. The effectiveness and efficacy of the MBLCR approach are evident in the QoS performance metrics obtained from the extensive simulation using different device speeds. Overall, it can be proven that the MBLCR outperforms as compared to the MP-OLSRv2, MEQSA-OLSRv2 and EMBLR schemes, respectively. It can be concluded that D2D communication in future wireless network applications is data-hungry, demanding that various research challenges in a heterogenous network domain are met.  
Conceptualization, V.T. and S.P; methodology, V.T. and S.P.; software, V.T.; validation, V.T., T.S. and S.P.; formal analysis, V.T.; investigation, V.T.; resources, V.T. and S.P.; data curation, V.T. and S.P.; writing--original draft preparation, V.T. and S.P.; writing--review and editing, V.T. and S.P.; visualization, V.T. and T.S.; supervision, V.T. and S.P.; project administration, V.T. and S.P.; funding acquisition, V.T. and S.P. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the MSIT (Ministry of Science and ICT), Korea, under the ITRC (Information Technology Research Center) support program (IITP-2022-2021-0-01810) supervised by the IITP (Institute for Information & Communications Technology Planning & Evaluation).  
The authors declare that there is no conflict of interest regarding the publication of this paper.
# LSOS: An FG Position Method Based on Group Phase Ranging Ambiguity Estimation of BeiDou Pseudolite
## 2 System Overview  
BeiDou array pseudo-satellite (BDAPS) is an independent indoor positioning system which can realize indoor independent networking without relying on any external connection. According to the characteristics of indoor space environments, a centralized array network, Beacon Cascade Network, and space distributed network can be built in indoor viewing environment. The base station is designed with multi-elements of the same source. The time-frequency reference parameters of the multi-channel pseudo-satellite signals are generated by a common clock source, and the multi-channel pseudo-satellite signals have strictly consistent time-frequency characteristics. Thus, each pseudo-satellite generates the same satellite clock error information. The core of BDAPS consists of time-frequency control unit, baseband signal generating unit, radio frequency unit, and antenna unit. The block diagram of the base station composition is shown in Figure 1.
# A Novel Approach for the Estimation of Doubly Spread Acoustic Channels Based on Wavelet Transform
## 5 Conclusions  
We have investigated the problem of doubly spread UWA channels estimation in this paper and proposed the WT-based algorithm. By using the superimposed HFM signal as training signal, the proposed algorithm only needs to search in time domain, and the Doppler scale factor and time delay can be simultaneously estimated. Therefore, it greatly reduce the computational complexity than OMP algorithm, while has slightly better performance.  
**Acknowledgments:** This work was supported by National Basic Research Program of China (973) (Grant No. 2013 CB336600), National Natural Science Foundation of China (Grant Nos. 61671144, 61372101, 61521061), National High Technology Research and Development Program of China (863) (Grant No. 2014 AA01A704), Fundamental Research Funds for the Central Universities and the Open Research Fund of Key Lab of Broadband Wireless Communications and Sensor Network Technologies (NJUPT), Ministry of Education (Grant No. NYKL201502), Funding of Supporting Excellent Young Professors for Teaching and Research in Southeast University, and Shandong Provincial Natural Science Foundation, China (Grant No. ZR2017 BF028).  
**Author Contributions:** The idea of this work was proposed by [PERSON]; [PERSON], [PERSON] and [PERSON] designed the framework and the experiments; [PERSON] and [PERSON] analyzed the data and wrote the paper; [PERSON] and [PERSON] helped revise the paper.  
**Conflicts of Interest:** The authors declare no conflict of interest.
# A Survey on Satellite Communication System Security
## 7 Future Research Directions
### Discussion  
Given the complex and evolving landscape of SCSs, prioritizing areas for research and development is crucial for stakeholders aiming to enhance security and functionality. Considering the maturity and development speed of technology, there are several research areas that should be prioritized at present.  
AI is considered to be the most important field in satellite communications. This is because AI is currently the fastest developing field, and at the same time, it makes the greatest contribution to SCS security. Therefore, leveraging AI in satellite communication could revolutionize security measures against sophisticated threats such as jamming and eavesdropping. However, this requires careful consideration of AI's vulnerabilities and the unique constraints of satellite environments.  
The development of SDSNs is another area of priority. By centralizing control and enhancing network resource allocation, SDSNs could dramatically improve the management of satellite constellations, addressing challenges like the link instability and variable latency. This is particularly important as the scale of networks like Starlink grows. However, the biggest problem with SDSNs is that integration with terrestrial networks is not easy, and this is thought to be a problem in a similar context to the integration of ground-space protocols.  
Lastly, advancing quantum communication technologies in SCSs holds promise for unprecedented security capabilities, although it is still in its early stages and requires substantial foundational research. Addressing these areas effectively would require a coordinated approach, balancing technological innovation with rigorous security practices to safeguard this critical infrastructure against both current and emerging threats.