esa-sceva/satcom-chunk-collection huggingface dataset:
# Motion Estimation of Non-Cooperative Space Objects Based on Monocular Sequence Images
## 5 Conclusions  
In this paper, a novel motion estimation method of non-cooperative space objects for autonomous navigation based on monocular sequence images is proposed. This method is not limited by the baseline length as in the stereo vision algorithm and has no constraints on the size and range of the object. It can be applied to asteroid exploration missions. This method does not require prior information such as the three-dimensional model of the object or artificial markers. It only uses the sequence images of the monocular camera to estimate the motion of the object. This method only uses image matching to obtain the motion estimation of the object, which avoids the problems of stability and convergence time of the filtering algorithm. Theoretically, only two images of the initial adjacent frames are needed to obtain the motion estimation of the object. This method has low calculation cost,  
Figure 9: Comparison of the object angular velocity in object-fixed frame. This figure is the comparison of the object angular velocity in the object-fixed frame. The red dotted curve is the result estimated by the proposed method, and the blue solid curve is the real state of the object simulation.  
runs stably and realizes the simultaneous modelling and estimation of the space moving object. Moreover, the algorithm only uses a basic matrix vector calculation, which is convenient for code transplantation and embedded implementation, and can well meet the requirements of real-time computation on board.  
Conceptualization, D.G.; Methodology, D.W.; Software, W.Z.; Investigation, W.E.; Data curation, R.D. 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 (U20B2055); the National Key Research and Development Program of China (2019 YFA0706500).  
The work not involving humans or animals.  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.  
The authors declare that they have no known competing financial interest or personal relationships that could have appeared to influence the work reported in this paper.
## 2 Methods
### Statistical Analysis  
Statistical analysis was performed using SPSS software version 27 (IBM Corp. Released 2020. IBM SPSS Statistics for IOS, Version 27.0. Armonk, NY, USA: IBM Corp). The dependent variable measured was peak force. The Shapiro-Wilk test was used to test for normality in all conditions. A two-way repeated measures ANOVA was used to determine whether there was an interaction between the independent variables and a dependent variable. The independent variables were the tests (AMTI\({}_{\text{RIGHT}}\), AMTI\({}_{\text{LEFT}}\), CS\({}_{\text{RIGHT}}\), CS\({}_{\text{LEFT}}\) and AMTI\({}_{\text{BI}}\)) and days (day 1 and 2). A paired samples t-test was used to compare (i) peak force on day 1 and day 2 for between sessions, and (ii) peak force for AMTI\({}_{\text{RIGHT}}\) and CS\({}_{\text{RIGHT}}\) and peak force for AMTI\({}_{\text{LEFT}}\) and CS\({}_{\text{LEFT}}\), on both day 1 and day 2. The \(p\)-value threshold for statistical significance was defined as \(p\) = 0.05.  
To examine the reliability of the C-station and the AMTI force plates, a test-retest analysis was made for between sessions. This was performed by an intraclass correlation coefficient analysis (ICC\({}_{3,1}\)). A two-way mixed effects model with absolute agreement was used, and the values of the ICC\({}_{3,1}\) (single measure) were assessed by an identification scale, where 0-0.49 is poor reliability, 0.50-0.74 is moderate reliability, 0.75-0.89 is good reliability, and 0.9-1 is considered excellent reliability [22]. While the ICC is a good measure of reliability, it is sensitive to sample heterogeneity. To counter this problem, coefficient of variation (CV) and standard error of measurement (SEM) were calculated to evaluate the absolute and relative reliability [23; 24]. It has been argued that a CV \(<\) 10% reflects an acceptable reliability for dynamic and isometric strength tests [25]. The concurrent validity between the C-station and the AMTI force plates was examined with Bland-Altman plots with 95% limits of agreement (LOA), as well as Pearson correlation coefficient analysis (PCC). The values of the PPC were assessed by an identification scale where 0.00-0.1 is negligible, 0.1-0.39 is weak, 0.40-69 is moderate, 0.70-0.89 is strong, and 0.9-1.0 is a very strong correlation [26]. Furthermore, the minimal detectable change (MDC) was calculated in the following way: \(MDC=1.96\times SEM\times\sqrt{2}\). The MDC% was calculated as follows: MDC% = MDC/average of the means obtained from the 2 tests \(\times\) 100.  
For all tests, mean and standard deviation were calculated. In addition to the paired \(t\)-tests, [PERSON]'s d effect sizes were used to determine the degree of significant differences between sessions, if any were observed. Effect sizes were interpreted as follows: trivial \(<\) 0.19, small 0.20-0.59, moderate 0.60-1.19, large 1.20-1.99, and very large 2.0-4.0 [27].
## 5 Materials and Methods  
For this study, we conducted communication experiments using two identical BG-22 Explorer Kit boards [70], which are based on the EFR32 BG22 SoC manufactured by Silicon Labs. We selected this device due to its rare WuR capabilities among BLE boards. The microcontroller's WuR feature was also evaluated. The manufacturer refers to it as RFSense. Additionally, we used an EFR32 xG22 Starter Kit that was equipped with the same SoC component. This kit was helpful for recording consumption measurements without the extra components present on the Explorer Kit boards. See Figure 8 for the two board variations.  
The EFR32 BG22 features several energy-saving features included in its energy modes (EMs). One of those EMs is dedicated to the use of WuR, whereas the others are more classical and analogous to the idle and sleep modes of other micro-controllers. Table 2 summarizes the operating components made available for each EM. We began our study by measuring the RSSI of a BLE message sent from one board to another from different distances. As the RF front end was shared between the WuRx and the BLE transmitter, it provided insight in the range that could be expected of the WuR according to the sensitivity given by the manufacturer. We conducted consumption measurements on different EMs to emphasize the energy benefits of WuR. Additionally, we compared WuR with other common BLE microcontrollers and SoCs. Finally, we determined the experimental range for the WuR implementation. A concise guide to implementing the code is provided. Based on our comprehensive literature review, our study provides a pioneering contribution to experimentally analyze WuR performance in terms of energy consumption and RSSI ranges using EFRBG22-based devices. To our knowledge, no research work has previously explored this aspect.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Energy Mode** & **Description** & **Peripheral Made Available** & **Expected Current Consumption** \\ \hline EM0 (Active) & Fully operational system & ARM Cortex M33 processor with DSP, FPU and TrustZone & 1.5 mA \\ \hline  & & Flash Memory, HF Oscillators, Main Radio Subsystem, USART, PDM, TRNG, Crypto Acceleration, & 0.96 mA \\  & & Time, Protocol Time & \\ \hline \hline \end{tabular}
\end{table}
Table 2: EFR32 BG22 operating components available depending on EM [70].  
Figure 8: EFR32 BG22 boards used in this study.
###### Abstract  
The cliff coastline of the central region of Asturias (N Spain) is severely affected by terrain instabilities, causing considerable damage to properties and infrastructures every year. In this study, we applied the A-DInSAR technique based on Sentinel-1 imagery to map and monitor active slopes in an emblematic rocky area of the Asturian coast: the Pehas Cape. The A-DInSAR dataset analysis has been focused at regional and local scales. For the local scale assessment, six areas were selected based on previous work and the landslide database of the Principality of Asturias region (BAPA-_Base de dates de Argyos del Principado de Asturias_), created by the University of Oviedo. The processing of the data has been performed using two independent sets of processing tools: the PSIG software tools, a professional tool and, the GEP service, an unsupervised platform. The dataset consisted of 113 SAR IW-SLC images acquired by the Sentinel-1 A/B satellites between January 2018 and February 2020. LOS mean deformation velocity maps (mm year\({}^{-1}\)) and deformation time series (mm) were obtained by PSIG and GEP software, allowing coastal areas with landslide incidence and other terrain movements to be distinguished. Deformation motion has been estimated from PSIG VLOS rates to be from \(-\)17.1 to 37.4 mm year\({}^{-1}\) and GEP VLOS rates from \(-\)23.0-38.3 mm year\({}^{-1}\). According to deformation time series (mm), the minimum and maximum accumulated displacements are \(-\)68.5-78.8 and \(-\)48.8-77.0 mm by means of PSIG and GEP, respectively. These ground motions could be associated with coastal instabilities related to marine activity and coastal retreat, both at regional and local study scales. The main contributions of this work are: (1) the demonstration of the potential of A-DInSAR techniques to evaluate coastal instabilities in a coastal retreat context and (2) the comparison of the results provided by the two sets of tools, which allowed the ground motion to be assessed by using an unsupervised approach vs. a contrasted one (robust software). This study increases the knowledge about coastal instabilities and other ground movements along the rocky coast and cliffs of Central Asturias. As a conclusion for the future, we believe that this work highlights the evaluated methods as significant tools to support the management of coastal territories with jagged and rocky coastlines.  
ground instability; rocky coast; Asturias; A-DInSAR; Sentinel-1 +
Footnote †: journal: remote sensing
# A Lightweight and High-Accuracy Model for Pavement Crack Segmentation
## 4 Results  
### Dataset  
This study primarily focuses on pavement crack detection, and therefore, we selected two public datasets as the research subjects: the Crack500 dataset for concrete pavement cracks [6] and the AsphalCrack300 dataset for asphalt pavement cracks [36]. The Crack500 dataset contains 3368 images of road cracks collected under various weather conditions, lighting, and angles, documenting cracks in different forms. The AsphalCrack300 dataset further expands the variety of crack types, with samples from different road scenes, featuring coarser road material particles and more varied crack forms. Many cracks in the Crack500 dataset are very thin or similar in color to the background, and some images contain noise such as shadows, gravel, and stains, adding complexity to the segmentation task.  
In this study, 1896 images from the Crack500 dataset were used for training, 1124 images for validation, and 348 images for final testing, with all images uniformly cropped to a size of 360 \(\times\) 640 pixels. To explore the generalization ability of the proposed method across different scenarios and crack types, the model trained on Crack500 was directly applied to all samples in the AsphalCrack300 dataset. This cross-dataset validation allows for the evaluation of the proposed method's performance on various crack types and road conditions, providing a better understanding of its applicability in real-world scenarios.
## 2 Security Protocols
### Transport-Layer Security
In order to guarantee a proper level of protection also against this kind of attacks, an intermediate security gateway may be required at the border of the internal network. A security gateway may act as access controller, granting access to the internal network only to trusted nodes. In [18,19], the authors specifically face this issue and try to propose a solution. In particular, in case of end-to-end application level communication based on CoAP, a solution may be to require the external node to encapsulate CoAP/DTLS/IP traffic within a proper DTLS tunnel established between the external node and the security gateway. It is also important to note that, although DTLS provides a datagram-oriented communication service (like UDP), it establishes a point-to-point secure association that is not compatible with multicast communications (in contrast with UDP, which does support multicast). In order to make DTLS applicable in multicast IP-communication scenarios, some protocol extensions for group-key management should be introduced in the future.
# An Improved Radio Resource Management with Carrier Aggregation in LTE Advanced
## 5 Limitations and Future Work  
The main objective of the proposed method is to improve the QoS with carrier aggregation by allocating RBs efficiently to the user. In the case of a higher number of users in the cell, average  
Figure 11: Throughput comparison of LTE and LTE-A user.  
Figure 10: Spectral efficiency for different number of users.  
throughput decreases due to the higher congestion and lack of available resources. Fairness index is also not showing a significant improvement, although the proposed method performs better than other methods.  
As a future work, the plan is to extend the radio resource management approach by introducing enhanced multiple input multiple output (MIMO) technique. This will help to increase the capacity of the cell. QoS of the cell-edge user and user with bad channel condition will improve with additional antenna and more transmission capability of the enhanced MIMO technique. Moreover, this technique can serve more users to reduce the aforementioned limitations. Coordinated multipoint transmission and reception (CoMP) is another system which can boost the user throughput. By adding these systems to the resource management approach, users will have further improved system efficiency and better coverage in the future LTE-A network.
## 3 AoI Minimization in UAV-Assisted WSN/IoT Application Architectures
### Trajectory and Energy Management (TE)
#### 4.2.3 TE with Data Collection Time  
Backscatter communication systems have been rarely studied in the prior literature on AoI-aware UAV-assisted IoT applications despite their prospect for the efficient utilization of energy in such scenarios. Moreover, notions of AoI that differ based on the initial calculation time have appeared in the literature. Motivated by these, ref. [106] considered a backscatter IoT communication architecture and calculated AoI from the latest data updating time. The studied scenario is more appropriate when sensors periodically update data. Particularly, the sensor nodes transmit data to the UAV via passive backscatter communications (Figure 10b). In the considered architecture, the UAV leaves the data center, collects data from sensor equipment one after the other, and returns to the data center for data processing. The authors aimed to find the optimal average AoI by jointly considering UAV trajectory, UAV transmit power and data collection time from each piece of sensor equipment to increase the sensor equipment's lifetime. To achieve this, they formulated a new AoI minimization problem including discrete (collection sequence of sensors) and continuous (transmission power and data collection time) variables. The problem is difficult to solve directly, so it was divided into two subproblems. The problems required the optimization of continuous (using KKT conditions) and discrete variables, while the backtracking method for trajectory design was proposed.
# Reflection Propagation Law of Electromagnetic Waves in U-Shaped Roadway
## 3 U-Shaped Roadway Model and Reflection Path Validity
### Reflection Path Validity  
The number of the second-time to eighth-time valid reflection lines in the U-shaped roadway can be calculated based on the determination of valid reflection paths. The following is the specific procedure for determining four-time, five-time, and six-time valid reflection paths:
## 4 Results and Discussion  
### DA-OA-ICOS Combined with White Noise Perturbation  
Currently, white noise perturbation was considered an effective method to improve the measurement accuracy of the OA-ICOS [28, 29, 30], particularly in suppressing the cavity mode noise. The generation of cavity mode noise was mainly caused by the coherence of the laser. The narrower the laser bandwidth, the better the laser coherence, and the greater the cavity mode noise generated [29]. When the control current of the laser was interfered with by white noise perturbation, the laser linewidth would be increased and the coherence would be decreased. The change effectively reduced the effect of cavity mode noise, thereby improving the SNR and measurement sensitivity [31].
# Bond Characteristics of a Deformed Steel Bar Embedded in Donut-Type Voided Slab
## 5 Conclusions  
In this study, bond experiments were performed to evaluate the bond characteristics of the deformed steel bar in the donut-type voided slab. Based on the results, the equation for calculating the bond strength considering bond characteristics of each region according to the void shapes and inner cover thickness in the donut-type voided slab was also proposed. The findings of this study are as follows.  
1. The bond stress-slip relationship of the donut-type voided slab was affected by the bond region according to the void shapes and inner cover thickness. Particularly, when the minimum inner cover thickness of 2.5 \(d_{b}\) was not satisfied, the difference of the maximum bond strength by bond region was large, and the failure behavior varied.
2. The bond stress distribution of the donut-type voided slab was also different from that of the general RC slab according to the inner cover thickness. When the inner cover thickness of 2.5 \(d_{b}\) was not satisfied due to the void, the average bond stress was found to be 25-50% lower than that of the general RC slab in the region of the minimum inner cover, and the bond stress was generated mainly at transition region in which sufficient inner cover thickness was ensured.
3. In the conventional method, which calculates the bond strength using the minimum cover thickness only, bond characteristics of the donut-type voided slab in regions where bond conditions varied along the longitudinal direction of the rebar were not reflected. Thus, it was found that the conventional method underestimated the bond strength of the donut-type voided slab.
4. In this study, the method of calculating the bond strength considering the bond characteristics of each region was proposed. The analytic results indicated that the error range between the estimated value and the experimental value was within 5%, thus confirming that the estimated bond strength of the donut-type voided slab was highly accurate.  
Original draft preparation and editing, J.-H.C. and H.-K.C.; Planning test program, H.-S.J. and H.-K.C.; performing tests and investigation, H.-S.J.; analyzing the results and reviewing the article, H.-K.C. and J.-H.C.; supervision and review writing, H.-K.C. All authors have read and agreed to the published version of the manuscript.  
This work is supported by the Korea Agency for Infrastructure Technology Advancement (KAIA) grant founded by the Ministry of LAND, Infrastructure and Transport (22 CTAP-C164325-02).  
Not applicable.  
Data is contained within the article.  
The authors declare no conflict of interest.
# Vibration Reduction of a Timoshenko Beam with Multiple Parallel Nonlinear Energy Sinks
## 3 Analysis Results
### Modal Analysis  
The performance of NESs is affected by the parameters, number, and locations of the NESs. Modal analysis is performed to present the differences between Timoshenko beam theory and Euler beam theory. A finite element beam is established with ABAQUS 6.14 to verify the accuracy of the first four resonance frequencies, and a B21 beam element is used. For a short beam [36], the ratio of length \(L\) to height \(H\) is from 2.5 to 5. Here, the constant parameters for the short beam and the nonlinear energy sinks are fixed to \(L\) = 1 m, \(H\) = 0.2 m, \(B\) = 0.2 m, \(E\) = 2.1 GPa, \(\rho\) = 7.8 \(\times\) 10\({}^{3}\) kg/m\({}^{3}\), \(a\) = 0.2 m, and \(F\) = 1 \(\times\) 10\({}^{5}\) N. The first four modal frequencies of the beam based on each theory are listed in Table 1. Compared with the finite element results, it is shown that as the order of modal frequency increases, the errors based on the Euler theory are obviously enlarged, while the frequency errors of each mode based on Timoshenko beam theory are within 1%. Thus, the response results in the following sections are solutions based on Timoshenko beam theory. It should be noted that the proposed method, based on Timoshenko beam theory, also applies to long beams with \(L/H\) > 5, and the results are similar to those based on [PERSON] beam theory.  
Figure 2: Flowchart of the genetic algorithm.  
The first four mode shapes are shown in Figure 3; the ratios of the first mode peak and the rest mode peak are nearly equal to 8:1. Thus, in the following section, the responses of the first mode are mainly considered, and the measuring point is set at \(x=0.6\) m, which does not only focus on the response of the first mode but also takes the rest mode into consideration. In the following figures, \(\overline{W}\) represents the amplitude of the steady-state response of the measuring point on the beam.
## 4 Discussion, Advantages, and Disadvantages  
The setup of this new radial-in-plane sensitivity interferometer that uses the divergent illumination is very simple and provides accurate measurements in radial directions. However, it does not allow for adjustments to the sensitivity vectors without losses in convergence in the illumination on the test surface. The measurements obtained by the proposed interferometer successfully support the presented mathematical model. It is shown that the radial-in-plane component contribution of the sensitivity vector is higher in comparison with the out-of-plane component; however, we can expect an error (less than 3%) near the centre of the observed area. Given the illumination convergence at the centre of the observed surface, it is difficult to obtain accurate measurements around the optical axis, so an alternative analysis is required.
###### Abstract  
To prevent pogo oscillation in liquid launch vehicles, it is essential to install a gas-filled accumulator near the pump with minimum flow inertance and a target-design level of flow resistance, which are the real and imaginary parts of communication port impedance. However, the present approach of estimating the flow impedance of the accumulator communication port based on an orifice flow model introduces a non-negligible error, possibly leading to accumulator failure. In this study, a transient computational fluid dynamics simulation is conducted on a communication port model, where the liquid oxygen is considered incompressible and \(k\)-\(\varepsilon\) turbulence model is used. The results indicate that the formation of a vortex downstream of the communication port leads to the attenuation of its linear resistance. A method for calculating the impedance of the communication port is proposed, where the impact of supply pipeline velocity, oscillatory flow amplitude, and frequency is considered. The results indicate that the quasi-steady assumption is suitable for oscillatory flow frequencies below 14.5 Hz, with a deviation of less than 30%. Above this frequency, a linear frequency correction can be used to reduce the deviation to less than 26.5% within the pogo frequency range. The impedance calculation formulae given in this research can be used in the engineering design of the gas-filled accumulators.  
impedance; communication port; accumulator; pogo suppression; liquid launch vehicle +
Footnote †: journal: Applied Sciences  
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