esa-sceva/satcom-chunk-collection huggingface dataset:
# Design and Implementation of Attitude Stabilization System for Marine Satellite Tracking Antenna
## 1 Introduction
In [7], the finite-time fault tolerant attitude stabilization control problem for a rigid spacecraft in the presence of actuator faults or failures, external disturbances, and modelling uncertainties is addressed. Again, only simulation studies are presented to demonstrate the effectiveness of the proposed schemes against actuator faults. Figure 1: Illustration of MSTA receiving satellite signals. proposed method. In these two papers, the proposed methods are not validated in real system, in which the working condition is much more complicated than simulation condition. In [8], a non-smooth attitude-stabilizing control strategy based on the finite-time control technique is investigated for flexible space crafts. In [9], a quaternion-based feedback control scheme for a quadrotor is proposed. The proposed controller is based upon the compensation of the Coriolis and gyroscopic torques and the use of a \(PD^{2}\) feedback structure. The problems of attitude stabilization and disturbance torque attenuation for a small spacecraft using magnetic actuators is considered in [10]. In [11], an original configuration of a small aerial vehicle having eight rotors is presented. Four rotors are devoted to the stabilization of the orientation of the helicopter, and the other four are used to drive the lateral displacements. In [12], a fault-tolerant control approach without rate sensors is presented for the attitude stabilization of a satellite being developed. These works have contributed a lot to the attitude control of MSTA, but because of the differences of control purpose, actuators and attitude sensors, few of these research results can be applied on the control system of MSTA. In this paper, the design and implementation of an attitude stabilization system of Ka-band MSTA is presented. The contributions of the present work are two-fold: (1) As the stepper motor is used in a close-loop system with the gyroscope for measuring shaft rotation velocity, the mathematical model of the stepper motor is identified with a method that is different from conventional method. (2) The robust controller based on \(\mathcal{H}_{\infty}\) loop shaping method is stated, which can make the tracking error less than \(\pm 0.15\) deg under the condition that maximum ship rotation velocity can reach \(26.2\) deg/s. The remainder of this paper is organized as follows: In Section 2, the diagram of the attitude stabilization system is introduced and two important electronic boards, the attitude sensor board and stepper motor control and drive board, are illustrated. In Section 3, the mathematical model of stepper motor is derived and some experiments are done to identify unknown parameters. The design procedure of a robust controller based on \(\mathcal{H}_{\infty}\) loop shaping is stated in Section 4. The designed attitude stabilization system is tested in Section 5 on a Stewart platform and the experimental results are analyzed. Lastly, Section 6 gives the conclusion.
Threshold methods presume that a phenological stage starts when either the VIs reaches a fixed VIs value (fixed threshold method) or a given amplitude of the seasonal change in VIs values (dynamic threshold method) [37]. The latter has been widely used and confirmed to be superior to the fixed threshold method in comparative research because it is more flexible and depends on the magnitude of \(NDVI\) variations over the growing season [15]. However, it requires attempts to determine the appropriate and optimal percentage threshold, which limits its wide range of applications. Until now, only a few studies have attempted to determine the optimal threshold for estimating a crop's phenological events. For instance, ref. [36] has investigated the optimal thresholds for retrieving the SOS and EOS metrics of different crops using MODIS time series data. In another study illustrating a calibration procedure to systematically optimise the derivation of the phenometrics of four crops (green-up, heading, and senescence), ref. [38] also used MODIS data and a BISE filter combined with SG. A similar study in [39] analyzed different threshold levels (10%, 15%, 20%, and 25%) of SOS and EOS to map key stages of corn growth at a field scale with 30 m resolution, using fused surface reflectance data. With higher resolution, reference [40] similarly extracted S2 SOS/EOS from various amplitude thresholds of \(NDVI\), \(EVI2\), and a new index called the \(PPI\) (plant phenology index) value. They linked them to specific plant phenophases, finding that \(PPI\) SOS at 25% and \(PPI\) EOS at 15% provided the best matches with the phenological stages observed on the ground. However, at this point, most crop phenology studies attempting to optimise phenological extraction are either limited to coarse satellite sensors, constrained to a few specific crop types, focused on small areas, or targeted to limited crop growth stages. These knowledge gaps have impeded our ability to connect high-resolution phenological metrics derived from \(NDVI\) to the stages of crop growth at the parcel level. Against this background, the primary aim of this study is to develop an innovative calibration procedure to accurately retrieve crop-specific phenophases at the field level of three major crops (winter wheat, corn, sugar beet) using high-quality reconstructed \(NDVI\) time series. Specifically, we seek to (1) introduce a robust method to filter the noise of the original \(NDVI\) time series for cloudy situations in Germany; (2) to determine the optimal dynamic thresholds for deriving the phenological metrics SOS and EOS based on the produced high-quality \(NDVI\) time series, making them more comparable and related to actual crop phenophases observations;(3) to demonstrate the effectiveness of the selected dynamic thresholds by aligning the detected phenology measures with independently recorded phenophases observed on the ground; (4) to generate field-level crop-specific phenophase date maps for three federal states in Germany using the selected dynamic thresholds.
# Design and Calibration of a Tri-Directional Contact Force Measurement System
## 3 Calibration  
### Calibration Setup and Procedure  
In order to check the feasibility of the proposed measurement system, a classical calibration procedure was performed to assess the level of mechanical coupling between the three branches and to define a decoupling matrix to be used during the experiment to measure actual contact forces. For the calibration, three wire-pulley systems were setup to apply tensile forces in the axial direction of each sensor with the help of dead weights. The dead weights were suspended with wires over pulleys, connected to hooks that were fastened on the face of the cube opposite to the face where the force sensor was attached as seen in Figure 3a. The measurement setup consisted of HBM QuantumX MX410 measurement amplifier that was used with MX Assistant software to acquire and record force sensor output values. HBM QuantumX MX410 was used because it is a highly dynamic 4-channel data acquisition module that offers high precision with accuracy class of up to 0.05%, high resolution of up to 200 kS/s and noise suppression capabilities using the Bessel filter. The force measurements were acquired at the rate of 4800 Hz.  
The calibration procedure involved sequential application of pure forces in the form of known loads in one direction at a time using a set of dead weights with no eccentricity. Before the loads were applied, all the force sensors were reset and zeroed after the mounting and assembly. The weights suspended using the wire-pulley systems, were then gradually increased with a fixed force interval from 0 to 100 N and sensor output values were recorded for each force sensor for each orthogonal direction. Only tensile forces were applied to each force sensor assuming linear behaviour in both the axial directions. The calibration procedure was carried out for the measurement system with locknut collar links and necked collar links alternatively. In order to investigate the repeatability of force measurement system, the calibration procedure was also repeated after disassembling and reassembling the calibration setup.
# Controllable Height Hopping of a Parallel Legged Robot
## 1 Introduction
In this paper, focusing on controllable vertical hopping, we describe the development of the parallel legged robot with a high-performance actuator, and use current-torque control on the actuator to implement VMC on the leg; this approach does not require an extra torque sensor but can provide active compliance in jumping and landing. Next, an ideal dynamic model was constructed and the fitting relationship between the virtual model setting and the actual hopping height was generalized. Finally, the control parameter was optimized in simulation and hopping height control was realized based on the proposed model. The main contributions of this paper are:  
1. To balance requirements of high output, transparency and applicable size of legged robot for vertical hopping motion, a design of integral legged robot system was developed. The actuator used BLDC-harmonic actuator and the main structure is parallel mechanism, which are relatively more suitable for legged robot to perform greater height hopping. 2. To realize controllable height hopping, a novel height control strategy combined with VMC, using dynamics model construction and function parameter fitting, was proposed, which is appropriate for our mechanical design and can also meet the requirement without extra sensor measurement and online calculation. The remainder of this paper is organized as follows. Section 2 introduces the design concept and the details of the robot. Section 3 establishes the dynamic model of the robot system. Section 4 describes the methods for VMC and hopping height control. Section 5 presents the simulation and experimental results. Finally, Section 6 draws conclusions about the consequences of our research and discusses future planning.
## 1 Introduction
### Contribution  
Regarding the TM-UAVs in performing APH tasks such as aerial horizontal interaction, the paper on the Tilt-Hex [3] claimes that a fixed TM-UAV has a laterally bounded force capability, and research on the omnidirectional aerial vehicle [4] mentions that it possesses full force and torque controllability in all three dimensions, while the paper on the tiltrotor OMAV [10] explains that a variable TM-UAV can exert omnidirectional wrench on the environment. However, considering the torque and power of the actuators used, the horizontal pulling force could be further maximized. This limitation arises because not all propellers can tilt in the same direction. Other TM-UAVs face similar constraints. Additionally, fixed TM-UAVs struggle to adjust the magnitude of horizontal pulling force while hovering, indicating that merely changing the thrust force of the propellers without altering their tilt angle is insufficient. Therefore, it is evident that TM-UAVs should be capable of tilting all propellers in the same direction to maximize horizontal pulling force.  
Therefore, to address the issue of insufficient horizontal pulling force of M-UAVs as aerial manipulators, this paper proposes a design for an aerial robotics system featuring a tiltrotor quadcopter UAV, named Tilt-X, as shown in Figure 1. As shown in Figure 1, since the M-UAVs have under-actuation properties, they find it difficult to exert a horizontal pulling force on the environment, making it hard to separate an attached object from the wall. The proposed Tilt-X is designed to be suitable for performing aerial horizontal interactions. Thus, it can exert a maximized horizontal pulling force on the environment, as shown in Figure 1, by tilting all propellers in the same direction backward from a wall. In addition, it is also suitable for performing aerial torsional interactions. It can maximize vertical torsional wrench, i.e., yaw moment. While the underactuated M-UAVs find it challenging to exert a large vertical torsional wrench, making it difficult to turn a valve, as shown in Figure 1, the proposed Tilt-X can generate a bigger yaw moment to turn the valve by tilting two pairs of propellers symmetrically in opposite directions, as illustrated in Figure 1.
## 3 Discussion
### Atypical Response Patterns  
[PERSON] et al. [36] evaluated CT manifestations of atypical responses in mRCC patients treated with ICIs [36]. Fifteen patients were treated with ipilimumab-nivolumab, while 31 patients received single-agent ICI (nivolumab or pembrolizumab) treatment. Most patients were nephrectomized and had the histological variant ccRCC. Moreover, 56.5% of patients underwent concurrent radiotherapy. Most patients (80.4%) fell into the intermediate and poor IMDC risk groups. Twenty-four patients (52.2%) showed an atypical response pattern, while eighteen patients (39.1%) experienced multiple atypical response patterns. Pseudoprogression was found in 15 patients (32.6%), dissociated responses in 22 patients (47.8%), and abscopal responses in 9 patients (19.6%). Five patients showed a late response (10.9%), and in two patients there was evidence of durable control of disease after cessation of ICI therapy. Serial pseudoprogression was observed in four patients with pseudoprogression (8.7%) and in one patient with symptomatic pseudoprogression (2.2%). Serial pseudoprogression was observed when comparing metastases of different organs, as well as metastases of the same organ. In most of the patients, isolated abscopal responses were found in one or two lesions, while two patients showed more abscopal responses in the lungs and liver. Other interesting immune phenomena observed included immune-related lieitis and pneumonia [36]. It is interesting to note how artificial intelligence can be decisive in the differential diagnosis of ICI-related pneumonia from other etiological agents [37].  
This study demonstrated how atypical response patterns have a high incidence in mRCC patients receiving ICIs. Knowledge of the atypical response to ICIs in mRCC patients is of fundamental importance for radiologists, to give a correct interpretation of response to therapy together with prompt recognition of possible side effects. The level of evidence of this study was 2. Knowledge of these patterns is crucial for patient management and for improvement of clinical outcomes.
# Assessment of Different Deep Learning Methods of Power Generation Forecasting for Solar PV System
## 1 Introduction
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Ref.** & **Year** & **Method** & **Inputs** & **Horizon** &
\begin{tabular}{c} **Best Results of** \\ **Accuracy** \\ \end{tabular} \\ \hline
[10] & 2009 & ANN &
\begin{tabular}{c} Air temperature, relative \\ humidity, and sunshine \\ \end{tabular} & Hour & MAPE (\%): 8.84 \\ \hline
[16] & 2016 & KNN & DNI, DHI, ambient temperature & Hour & MAPE (\%): 18.25 \\ \hline
[17] & 2020 & LSTM & \
\begin{tabular}{c} Solar irradiance, temperature, \\ relative humidity, and \\ wind speed \\ \end{tabular} & 24 h &
\begin{tabular}{c} MAPE (\%): 22.31 \\ RMSE: 0.71 \\ MAE: 0.36 \\ \end{tabular} \\ \hline
[23] & 2014 & SVR & \begin{tabular}{c} Temperature, probability of \\ precipitation, and solar irradiance \\ \end{tabular} & \
\begin{tabular}{c} One-day-ahead \\ hourly \\ \end{tabular} &
\begin{tabular}{c} MRE [5] (\%): 3.295 \\ \end{tabular} \\ \hline
[26] & 2019 & \begin{tabular}{c} BPNN \\ ELM [1 \\ \end{tabular} & \
\begin{tabular}{c} Sunshine hours, global radiation, \\ and UV index \\ \end{tabular} &
\begin{tabular}{c} One-hour-ahead \\ \end{tabular} & nRMSE [6] (\%): 7.75 \\ \hline
[30] & 2018 & DEPSO [2 \\  & & \begin{tabular}{c} Tipping Bucket Rain Gauge, wind \\ speed, wind direction, air \\ temperature, relative humidity, \\ and solar radiation \\ \end{tabular} & Hour & \
\begin{tabular}{c} RMSE (\%): 4.4\% \\ MAE: 0.03 \\ MBE: \(-\)1.63 \\ VAR [7 \\ \end{tabular} : 0.01 \\  & &
\begin{tabular}{c} WME [8 \\ \end{tabular} : 0.16 \\ MRE (\%): 3.1 \\ \end{tabular} \\ \hline
[31] & 2019 & Hybrid &
\begin{tabular}{c} Tipping Bucket Rain Gauge, wind \\ speed, wind direction, air \\ temperature, relative humidity, \\ and solar radiation \\ \end{tabular} & Hour & MAPE (\%): 1.7052 \\ \hline
[32] & 2021 & \begin{tabular}{c} Two-stage \\ attention-based \\ encoder-decoder \\ over LSTM \\ \end{tabular} & \begin{tabular}{c} Forty-one features, including \\ solar radiation, temperature, \\ humidity, snowfall, albedo, etc. \\ \end{tabular} & One-day-ahead & \
\begin{tabular}{c} RMSE: 0.0638 \\ MAE: 0.0324 \\ \end{tabular} \\ \hline  & &
\begin{tabular}{c} \({}^{1}\) ELM: Elaboration Likelihood Model; 2 DEPSO: Discrete Evolutionary Particle Swarm Optimization); 3 GA-SVM: Genetic Algorithm and Support Vector Machine; 4 MRAE: Mean Relative Absolute Error; 5 MRE: Mean Relative Error; 6 nRMSE: normalized Root Mean Square Error;7 VAR: variance of the prediction errors; 8 WME: Weighted Mean Errors. \\ \end{tabular} \\ \hline  & & & & \\ \end{tabular}
\end{table} 
Table 1: Summary of different forecasting algorithms, data inputs, and horizons. modeling and evaluation methods. Section 5 presents the numerical PV power forecasting results, followed by the final section for the conclusion.
## 6 Discussion
In contrast to the superior performance of our proposed EfficientNetB7-SK-UNet in experiments, our model still faces some limitations. One of the shortcomings of our methodology is its weakness in classifying minor- and major-damaged buildings. This can be further improved by training on a more diverse dataset that contains more instances of these complicated classes. Another one is that pancake collapses of multistory buildings or facade damages cannot be assessed from satellite images [29; 30]. Damage assessment based on satellite images is limited to near-nadir observations, and most of the time, only rooftop damages can be detected. Similarly, although the xBD dataset is currently the largest dataset for building damage assessment, the imbalance of classes and disaster types, as well as complexities in the pre- and post-disaster image acquisition conditions, makes it a challenging dataset to support general solutions. Therefore, huge efforts are still required to generate high-quality annotated datasets for building damage assessment. Multi-modal datasets that leverage the synergistic potential of multiple sensors, such as SAR or LiDAR, along with high-resolution optical satellite images or oblique UAV imagery, should be generated. Such datasets can provide more comprehensive and accurate information for damage assessment and disaster response, significantly contributing to damage assessment operations and the development of the scientific community. Finally, training deep neural networks, especially the semantic segmentation models, usually takes up to several hours and requires large numbers of annotated data. This is not suitable for real-world disaster situations where fast decision-making is critical. Developing more robust and lightweight models will help in tackling these limitations. Urban planning and infrastructure monitoring are important applications of remote sensing technologies and satellite imagery. In this regard, utilizing satellite imagery as a valuable source for monitoring urban changes can help plan for future developments. Accordingly, the dual-branch UNet architecture, which proved its applicability in semantic segmentation, can be used in further developments for building footprint localization and change detection applications using bi-temporal satellite images. Developing useful and automated applications for handling various real-world problems, such as those  
Figure 23: The relation between “disaster types” and the “classification” quality metrics. mentioned above, requires robust, efficient, and scalable algorithms that can be used with less training effort. Accordingly, appropriate hardware, i.e., more powerful computing resources, empowered with lighter networks that can train faster while achieving the same performance as heavy models, are the future of artificial intelligence applications.
## 3 Proposed Solution
### Proposing the Fusion of MP-WFRFT and DM Algorithms Based on the VPAPM Scheme
Simulation 2 (Obtaining \(BER_{2}\)): Activate only the MP-WFRFT system (by setting the DM to an omnidirectional transmission mode). Simulate the BER for an eavesdropper using an incorrect security key (\(\alpha_{e}\),\(V_{e}\)), yielding \(BER_{2}(\alpha_{e},V_{e},SNR)\). 3. Simulation 3 (Obtaining \(BER_{total}\)): Run the complete, integrated system. Simulate an eavesdropper who is simultaneously at an incorrect angle and using an incorrect key, yielding \(BER_{total}(\theta_{e},\ a_{e},\ V_{e},\ SNR)\). 4. Calculate k: Calculate the value of k over a large number of parameter points (different \(SNR\), \(\theta_{e}\), \(\alpha_{e}\), etc.) using the formula \(k=(BER_{total}-BER_{2})/(BER_{1}\cdot BER_{2})\). In our simulations, to simplify the analysis, we select the average value of k, evaluated over a set of typical scenarios, for our assessment. While the proposed scheme offers superior security, it is important to acknowledge the associated trade-offs in terms of system complexity and power consumption:  
1. Computational complexity: In MP-WFRFT, the complexity of computing the weight \(w\) is \(O(1)\), and that of the weighted sum is \(O(N)\), while the fast Fourier transform (FFT) has a computational complexity of \(O(N\log N)\). As \(N\rightarrow\infty\), \(O(N)\ll O(N\log N)\). Consequently, the time complexity of MP-WFRFT is \(O(N\log N)\), primarily determined by the length \(N\) of the discrete sequence. Moreover, both the time and space complexities of the DM algorithm are \(O(N_{A})\) (where \(N_{A}\) is the number of antenna elements), corresponding to linear complexity. Thus, it is evident that the integrated MP-WFRFT and DM algorithm exhibits a relatively low complexity, facilitating its practical implementation. 2. Power consumption: Increased digital processing and the need to drive a multi-element antenna array for DM will lead to higher power consumption. However, this is partially mitigated by one of the core components of our scheme. The use of PAPM is known to improve the power efficiency of the satellite's high-power amplifier (HPA) by reducing the peak-to-average power ratio (PAPR) compared to that of some traditional modulation formats.