esa-sceva/satcom-chunk-collection huggingface dataset:
# Performance Evaluation of CF-MMIMO Wireless Systems Using Dynamic Mode Decomposition
## 6 Results
### Performance Evaluation of DMD in a System Considering Delay-Doppler Correlated Channel
(**A**) The 95%-likely per-user coherent downlink Spectral Efficiency (SE) against the value of \(f_{D}T_{s}\) for coherent transmission (\(L=100\), \(K=20\), \(N=2\), ASD \(=30^{\circ}\)). (**B**) The 95%-likely per-user non-coherent downlink Spectral Efficiency (SE) against the value of \(f_{D}T_{s}\) for non-coherent transmission (\(L=100\), \(K=20\), \(N=2\), ASD \(=30^{\circ}\)). Figure 25: Average SE per UE against L (number of APs), with \(\tau_{p}=7\), \(K=10\), \(N=8\) and \(p_{k}=100\) mW for each UE. The performance is evaluated for various channel estimators, providing insight into how the distribution of the SE of the system changes with different estimation techniques. Figure 27 illustrates the average Spectral Efficiency (SE) per User Equipment (UE) against the pilot sequence length, \(\tau_{p}\), with \(\tau_{\rm S}=20\), \(K=10\), \(N=8\), and \(p_{k}=100\) mW for each UE. It shows the impact of Channel Estimation on the global network performance based on the number of pilots \(\tau_{p}\). Generally, a higher number of pilots improves Channel Estimation; however, it also reduces the network's effective traffic. The figure illustrates that non-DMD algorithms still increase global network traffic as the number of pilots increases. DMD schemes reach a point where the increase in pilots greatly decreases the global network traffic. Intuitively, this is because DMD requires significantly fewer pilots for accurate Channel Estimation. Figure 26: CDF of UL sum SE for \(K=50\) as a function of the number of AP antennas for different channel estimators. Figure 27: Average UL SE[bits/s/Hz] vs. number of time–frequency snapshots \(\tau_{p}\).
## 4 Results and Discussion
### Overall Analysis  
The correctness of the equation model was verified by software simulation. When the temperature sensor measures the temperature of actually near space, it can calculate the measurement errors (Joule heat, radiant heat, and aerodynamic heat) of the temperature sensor by collecting information from other physical quantities.  
Among them, due to the high-speed motion of the radiosonde, the sensor temperature rise caused by aerodynamic heat up to tens of Kelvins, which is the most influential factor in the three temperature errors. In addition, as a result of the presence of the radiation-proof layer, the temperature rise caused by the large solar radiation of 2000 W/m\({}^{2}\) is much less than 1.00 K. Therefore, using the constructed temperature error model, the real atmospheric temperature value can be accurately calculated by the actual measured temperature value.
## 3 Preliminaries
### Lsss  
Let \(U=\{u_{1},u_{2},\ldots,u_{n}\}\) denote the set of attributes. A Linear Secret-Sharing Scheme (LSSS) \(\Pi\) over the finite field \(\mathbb{Z}_{p}\), where \(p\) is a prime number, is defined as follows:  
(1) Each share linked to an attribute is represented as a vector in \(\mathbb{Z}_{p}\).  
(2) A matrix \(\mathbb{M}\in\mathbb{Z}_{p}^{n\times h}\) exists, which generates the shares for \(\Pi\). The mapping \(\rho:\{1,\ldots,n\}\to U\) associates each row of the matrix \(\mathbb{M}\) with a specific attribute. Let the vector \(\mathbf{v}=(s,r_{2},\ldots,r_{h})^{\top}\) represent the values, where \(s\in\mathbb{Z}_{p}\) is the secret and \(r_{2},\ldots,r_{h}\in\mathbb{Z}_{p}\) are randomly selected values. The shares of the secret \(s\) are obtained by computing the product \(\mathbb{M}\mathbf{v}\). Each share \(\lambda_{i}=(\mathbb{M}\mathbf{v})_{i}\) is assigned to the attribute corresponding to \(\rho(i)\).  
An LSSS is characterized by a fundamental linear reconstruction property [40]. Specifically, given an LSSS \(\Pi\), an access structure \(A\), and an authorized set \(S\in A\), let \(I=\{i:\rho(i)\in S\}\) represent the indices of the rows in \(\mathbb{M}\) that correspond to the attributes in \(S\), where \(I\subset\{1,\ldots,n\}\). If the shares \(\lambda_{i}\) are valid for the secret \(s\), there exist constants \(\omega_{i}\in\mathbb{Z}_{p}\) for each \(i\in I\) such that the secret can be reconstructed by the following linear combination of shares: \(\sum_{i\in I}\omega_{i}\lambda_{i}=s\).
# Methodology for CubeSat Debris Collision Avoidance Based on Its Active ADCS System
## 4 Results and Discussion
### Distances Calculation
#### 4.1.3 Maneuver BC  
Maneuver BC is performed when the CubeSat changes its orientation from the initial position B to the final position C. This maneuver represents two different scenarios: for 6U CubeSat from 3-unit drag face to 2-unit drag face and vice versa. Figure 8 shows the results of HDD and VDD for the three different orbits under study.  
Figure 7: Results for two days after Maneuver AC for all satellites under study.  
The three CubeSats show similar evolutions during the two days regarding HDD and VDD, but with different effects. SAT-L, the one with the lowest orbit, shows the highest distance in each instant, and SAT-H, the one with the highest orbit, shows the lowest distance in each instant. SAT-M shows intermediate distances, between SAT-L and SAT-H. In all cases, the VDD varies proportionally with time and HDD shows an exponential behavior. The maximum VDD achieved by the maneuver corresponds to SAT-L, with 53.13 m, an intermediate value of VDD is reached by SAT-M with 28.42 m, and the minimum VDD is 14.10 m for SAT-H. On the other hand, the maximum HDD achieved by the maneuver corresponds to SAT-L, with 2.61 km, an intermediate value of HDD is reached by SAT-M with 1.38 km, and the minimum HDD is 0.68 km for SAT-H.
# Automated Evaluation of C-ITS Message Content for Enhanced Compliance and Reliability
## 3 Results
### Scenario 1  
In this scenario, the C-ITS SIM system was configured to transmit CAMs (Cooperative Awareness Messages) with the following setup:  
* Station Type: \"trailer\"
* Vehicle Role: \"dangerous goods\".  
The objective was to evaluate how a third-party unit, acting as a receiver, processed and logged these CAMs. The testing involved transmitting 44 CAMs from the C-ITS SIM, and the third-party unit was responsible for capturing and logging these messages. The results were analyzed to verify if the received messages adhered to the expected parameters and to identify any issues.  
The main goal was achieved. The third-party OBU successfully captured all C-ITS messages that were broadcast. The CAMs transmitted by the C-ITS SIM were verified to comply with the relevant standards, as shown in Table 1.  
This table breaks down the number of parameters evaluated across different containers in the received messages. The \"Total\" column shows the number of parameters analyzed for each container, while the \"OK\" column indicates how many were received without issues. The \"Warning\" column highlights parameters that trigger warnings, often due to unavailable values.  
A few warnings were observed, mostly related to the C-ITS SIM's configuration. For instance, some confidence parameters were not explicitly set; however, their values still adhered to the \"unavailable\" designation specified by the standards.
## 4 Current Status and Identified Needs
### Level 1 TOA Radiometry and Geometry
#### 4.1.1 Pre-Flight Calibration  
Radiometric calibration is the result of a long and complex process, starting with the rigorous pre-launch characterisation activities. The aim of these activities is to characterise the sensor response in a range of operational conditions that mimic those that will be experienced in space. Any flaws in the acquisition and analysis of pre-launch calibration data or lack of specific characterisation measurements could induce a potential systematic error in the resulting higher-level data products. This error will be difficult to correct in-orbit, since the relevant characterisation measurements could not be feasible in space or could be performed with limited accuracy as compared to the one that can be attained in laboratory conditions.  
It is therefore essential to pay extreme attention and ensure appropriate support to pre-launch characterisation activities. In addition, it is important from a user perspective, to guarantee full visibility of the results of the pre-launch characterisation measurements, both the raw data and the derived calibration factors, to allow a full traceability along the processing chain. As a matter of fact, several recommendations were identified during the Fiduceo project [67] on the importance of pre-flight calibration activities and on the need to store and preserve this information for future mission reprocessing campaigns. The Space Agencies should embrace such recommendations and ensure that metrological best practices are embedded in the early phase of the mission design.
# Energy Consumption Analysis of ISO/IEC 29192-2 Standard Lightweight Ciphers
## 4 Test Environment, Scenario, and Results
### Test Scenario
Although microcontroller architecture such as instruction set design, memory hierarchy, and power management can influence absolute performance metrics such as energy consumption and runtime, it is expected that the relative performance differences among the algorithms tested will remain largely consistent across platforms. In other words, an algorithm that performs more efficiently than others on the MSP430 FR5994 is likely to maintain its relative advantage on other embedded systems as well. This observation strengthens the validity of the comparative results obtained in this study and supports their generalizability to a broader range of IoT platforms. The test scenario considers only the encryption and decryption processes inside the device under ideal conditions. Other factors such as data generation and transmission to the network are not included in the study. This is because the focus of this study is to analyze the pure performance of the algorithms adopted in the ISO standards. Thus, by providing a test environment free from environmental factors, it is aimed to evaluate the basic metrics of the algorithms such as energy consumption and runtime in the most accurate way.
###### Abstract  
Obtaining ultracold alkaline earth(-like) atoms in space encounters the problem of performing narrow-line laser cooling in microgravity environments (\(\mu\)-gEs). This paper reports an analysis of the magneto-optical trap (MOT) based on the narrow-line transition in \({}^{88}\)Sr, while paying special attention to the role of the gravity. This analysis suggests the MOTs based on narrow-line transitions cannot be cold and dense enough in a \(\mu\)-gE. We thus propose a strategy: that one can use a dual-frequency MOT to realize a low-temperature, high density, and high transfer efficiency, narrow-line red MOT in \(\mu\)-gEs.  
lasering cooling and trapping; microgravity; Monte Carlo simulation; optical lattice clocks; in space +
Footnote †: journal: Applied Physics Letters  
_Applied Physics Letters_  
Explorer) is also based on a strontium optical lattice clock in space [29]. Furthermore, strontium atoms can be a good candidate for developing atom interferometry in space [29,30].  
Thanks to the existence of the transition line of \((5s^{2})^{1}S_{0}-(5s5p)^{3}P_{1}\), experiments of narrow-line laser cooling of strontium atoms in magneto-optical traps (MOTs) show that the temperature can be down to the recoil limit for both bosons and fermions [31, 32, 33, 34]. Another interesting property of the narrow-line laser cooling of strontium atoms is that the ratio of the maximum radiative force to the gravitational force \(R=\hbar k\Gamma/2\,mg\) is about 16, where \(\hbar\), \(k\), \(\Gamma\), \(m\), and \(g\) are the reduced Plank's constant, the light field wave vector, the transition natural width, the atomic mass, and the gravitational acceleration, respectively. This ratio is much different from the laser cooling based on the broadlines, where R is typically on the order of \(10^{5}\). One can observe that the atoms tend to sag to the bottom of the MOT where the Zeeman shift balances the laser frequency detuning. This phenomenon demonstrates that the gravity of earth can play a strong influence on the behavior of the strontium atoms in the MOT held by this narrow-line transition. One question then arises: how would the narrow-line laser cooling be if the experiment runs in a \(\mu\)-gE. To the best of our knowledge, this problem has not been studied in detail. Meanwhile, it is costly to establish a \(\mu\)-gE on the ground for such an experiment. Simulation is thus important and necessary for understanding and designing a narrow-line MOT in a \(\mu\)-gE. We herein show the numerical modeling of the atoms' behaviors to understand the role gravity plays in narrow-line MOTs of strontium atoms and propose a possible solution to realize efficient, narrow-line laser cooling with microgravity.
###### Abstract  
Global navigation satellite systems (GNSSs) have been booming in recent years, and the space segment of all four of the GNSSs, including BDS (BDS-3/BDS-2), Galileo, GPS, and GLONASS, has almost been fully deployed at present. The single point positioning (SPP) technology, which is widely used in satellite navigation and low-accuracy positioning, can benefit from the multi-GNSS integration, but the additional intersystem bias (ISB) parameters should be introduced to ensure the compatibility among different GNSSs. In this study, the ISB estimates derived from four-system integrated SPP are carefully characterized, and the performance enhancement attributed to a priori ISB constraints by prediction for position solutions under open sky and constrained visibility environments is rigorously evaluated. The results indicate that the ISB between BDS-3 and BDS-2 cannot be ignored. The daily ISBs show step changes when encountering the replacement of receiver types, while it is not the case for the receiver firmware versions. The daily ISBs are roughly consistent for the stations equipped with the same type of receivers. The short-term stability of epochwise ISBs for GLONASS, Galileo, BDS-2, and BDS-3 with respect to GPS can be 2.335, 1.262, 1.741, and 1.532 ns, respectively, whereas the corresponding long-term stability for daily ISBs can be 1.258, 1.288, 2.713, and 2.566 ns, respectively. The single-day prediction accuracy of daily ISBs for GLONASS, Galileo, BDS-2, and BDS-3 with respect to GPS can be 1.055, 0.640, 1.242, and 0.849 ns, respectively. The improvements on positioning accuracy after introducing a priori ISB constraints can be over 20% at an elevation mask of 40\({}^{\circ}\) and 50\({}^{\circ}\) with a time span of ISB prediction of a day. As to the availability, it is only 64.0% for traditional four-system SPP under a cutoff elevation of 50\({}^{\circ}\), while the corresponding availability is increased to approximately 90.0% after considering a priori ISB constraints. For completeness, the characteristics of ISBs estimated with the low-cost u-blox MST receiver and the Xiaomi Mi8 smartphone as well as the contribution of a priori ISB constraints to the multisystem SPP solutions with these devices are also investigated.  
single point positioning; intersystem bias; multisystem combination; a priori constraint analysis. +
Footnote †: journal: remote sensing
## 4 Numerical Analysis of Pseudo-Dynamic Method
\(v_{\rm s}\) and \(v_{\rm p}\) are the shear wave velocity and primary wave velocity, respectively. \(\rho\) is the density of rock mass. In the numerical simulation, a point safety factor method was used to quantitatively analyze the bedding slope stability [35]. For this simulation, it took about 100 steps to calculate the seismic inertia force duration of 0.4 s, and the initial and final time steps were 0.004 s. Based on the Mohr-Coulomb constitutive model, the minimum point safety factor on the calculated element at any time of slope can be derived as  
\[F_{\rm min(f)}=\frac{2\sqrt{(\tan\varphi\sigma_{1}+c)(\tan\varphi\sigma_{3}+c )}}{\sigma_{1}-\sigma_{3}} \tag{18}\]  
where \(\sigma_{1}\) and \(\sigma_{3}\) are the maximum and minimum principal stress, respectively. \(c\) and \(\varphi\) are cohesion and internal friction angle of rock mass, respectively. Figure 14 shows the safety factor contours of the structural plane at different times. Obviously, the safety factor of structural plane 3 was lower than the other two positions, and the value of the safety factor was \(F\) = 0.847 at the time of 0.1 s. This once again indicates that structural plane 3 was the slip surface. For verifying the conclusion of the pseudo-dynamic method, the transient safety factor was compared between the numerical and analytical results, as shown in Figure 15. Firstly, it can be seen that before 0.1 s, the safety factors calculated by the different methods gradually decrease with time. The minimum safety factor of the numerical simulation was \(F\) = 0.847, which was close to the value of the pseudo-dynamic method \(F\) = 0.81. Therefore, both methods indicated that the bedding slope had been damaged. Secondly, the safety factor of the numerical method was almost unchanged at 0.1-0.2 s, but the result of the pseudo-dynamic method increased. The major reason for the difference is the essence of the calculated methods. The slip body is regarded as rigid in the pseudo-dynamic method,  
Figure 14: Safety factor of structural plane at different times. (**a**) \(t\) = 0.052 s; (**b**) \(t\) = 0.100 s.  
but a deformation body is adopted in the numerical calculation. Due to the feature that deformation is large before slope failure, the curve of the safety factor after instability will be divergent in the numerical result. Thirdly, although in general the numerical method obtained a slightly higher safety factor compared with the analytical data before 0.1 s, the evaluation standard for stability in this study was the minimum safety factor \(F\geq 1\), so the numerical results were in accordance with the conclusions of the pseudo-dynamic method.
# A Holistic Approach for Design and Assessment of Building-Integrated Photovoltaics Systems
## 3 Customized PV Modules Software Analysis
### Return on Investment  
An economic analysis was carried out to evaluate the profitability of the experimental setup, considering the following factors:  
* System capacity: the experimental system of 8 panels installed in the building with a generating capacity of 400 Wp.
* Cost per Wp installed: the cost of each Wp installed is USD1.6. This cost was taken from Table 1 where the unit installation prices of different photovoltaic generation technologies were compared, both for roofs and facades. In this case, the unit price of the monocrystalline silicon technology with facade installation was chosen.
* Exchange rate: an average value of 3400 COP/USD (TRM of 27 January 2020) was taken due to the constant variation of the TRM in the market.
* Total CAPEX: the total cost of the project. The value is obtained from the product of the total capacity of the system, the cost per Wp installed, and the chosen exchange rate. The total CAPEX of the installation used was USD 640.
* Average generation per year: this value was obtained from the simulation stage of the BIPV system (87,600 Wh/year).
* Energy price: the value is 0.165 USD/kWh. This price was obtained from energy utility bills and is influenced by socioeconomic factors and the location of the property.  
A summary of the above factors is presented in Table 1. The simple time of payback was calculated as a measure of the system's profitability. It provides the time in which the investment would be recovered according to the average energy generation per year. The evaluation yielded a payback time of 44.4 years. With a payback of 44.4 years, this project is not profitable because the average life of a solar system is 20 to 25 years [39]. Therefore, the analyzed BIPV system never achieves payback. Then, alternatives will be proposed to improve the project's financial results, considering nearby buildings and geospatial location. These aspects are of great importance when designing a photovoltaic system and will allow evaluation of the project's feasibility.
## 3 Methodology and Application to a Case Study  
### Method  
This study is focused on the development of PtG technologies in Spain, in the framework of an R&D project that includes the design of a specific methodology to estimate the socio-economic impact of PtG in the territory. The PtG process can be explained as follows: hydrogen is produced by water electrolysis that is subsequently combined with carbon dioxide to produce methane through the Sabatier reaction. These individual processes require a photovoltaic installation connected to an electrolyzer that feeds a methanation reactor and its auxiliary systems.  
We used a double-focus qualitative methodology to investigate the research questions through a case study. We conducted 15 semi-structured interviews during the first semester of 2020 to analyze the perceptions of experts about the deployment of PtG technologies in Spain. Parallel desk research was also carried out to select a set of specific indicators to estimate the socio-economic impacts of PtG in Spain.  
The questions in the interviews were designed in accordance with other studies that have concentrated on the adoption of RES technologies or the CE in a territory [71; 72; 73]. PtG development potential was analyzed based on the opinion of 15 experts selected by the authors as key informantsaccording to their background. Because of the stage of development of these systems, approximatively 50% of the interviewees represent R&D institutes, public administrations, or other organizations related to the development of the CE. The other half of the experts represent companies that operate in the energy sector. A brief description of the experts' profiles is included in Table 1, but owing to confidentiality agreements with the interviewees, their identities remain anonymous.  
The interviews were organized into three sections. Part A was focused on the analysis of the future deployment of PtG technologies through five open questions. Part B determined main barriers and drivers to this technology. Part C included closed and open questions related to the socio-economic impacts of PtG. Finally, basic data of the respondents were collected during the fourth part of the interview. Experts answered some of the questions using a Likert scale (All the interviews were analyzed in an aggregated manner using a qualitative method. In addition, experts were asked to assign a value to each opinion using a Likert scale ranging from 0 to 5 (0 means total disagreement, and 5 total agreement)).  
For the desk research on the measurement of the socio-economics impacts of PtG, different metrics were identified and applied to the case study. Three basic indicators were selected to synthesize the estimation of impacts of these technologies in Spain: capital expenditure (CAPEX), employment related to these investments, and the volume of CO\({}_{2}\) captured by these systems. The metrics and coefficients used in this study to define the impact of the CE in the deployment of PtG are consistent with previous studies, particularly those proposed by [PERSON] et al. (2018), [PERSON] et al. (2017), and [PERSON] et al. (2018) [74; 75; 76].