esa-sceva/satcom-chunk-collection huggingface dataset:
## 5 Conclusions  
This paper reports the design and exhaustive testing of an innovative biopotential readout circuit with a common-mode driven synchronous filtering of the PLI in ECG. The presented SF approach, and the one recently published in [37], set up a new standard for recording biosignals, in which the common-mode and the differential-mode signals are processed together. The SF approach applies to both systems with and without DRE. In the systems with DRE, the common-mode signal could be taken from the reference electrode. In order to be applicable for SF, AFE should be equipped with a common-mode amplification channel followed by an ADC. The SF approach was analyzed in detail, and the closed-loop bandwidth and stability considerations were determined. The SF approach is applicable to all permanent biosignals, taken with electrodes from the body surface like ECG, EEG, EMG, EOG, etc., and can benefit all diagnostic and therapeutic medical devices where these signals are in use. The implemented loop filters could be further optimized for different applications using other biosignals like EEG, EMG, EOG, etc. Note that the QRS limiter should be omitted. Moreover, such optimization can also be directed to better results by adding high-pass or band-pass pre-filtering in the common-mode chain of the analog or digital part. Note that increasing the Q factor would further stabilize the PLI amplitude but also reduce performance when the PLI frequency deviates from its nominal value. Fractional band-pass filters have recently been shown to potentially cope with this problem [67].  
The developed, implemented, and validated innovative design solutions and concepts are as follows:  
* A novel biopotential readout circuit processing both differential-mode and common-mode signals in systems with and without DRE.
* An innovative closed-loop SF algorithm, robust against amplitude and frequency variations in PLI.
* An optimized loop filter for operation with ECG signals.
* A novel QRS limiter with an adaptive threshold, effectively eliminating the QRS influence.
* A tricky all-digital open-loop AGC with a fast response and making possible the SF operation without SPLL.
* A novel, extensively tested, and validated concept using real and synthesized ECG signals and PLI with variable amplitude and frequency.
### Existing Solutions and Research Gaps
#### 1.1.2 Major Research Gaps  
Despite progress in cognitive radio networks (CRNs), several key research gaps remain to fully harness their potential. The following sections outline some of the current challenges in the field of cognitive radio that require further investigation:  
* Performance in Low-SNR Environments: While many techniques achieve high accuracy under ideal conditions, their performance often degrades significantly in low-SNR environments. Enhancing robustness in these challenging conditions remains an open research area.
* Robustness Against Noise and Interference: AMC systems must reliably classify signals under noise uncertainty and interference. More robust architectures or noise-resistant features are needed for better performance in noisy environments.
* Interference from Dynamic Environments: Existing methods often assume static environments, which is unrealistic. Methods that can adapt to dynamic conditions, such as varying channel conditions and interference, are necessary.  
These gaps present opportunities to enhance automatic modulation classification methods, focusing on improving their practicality, efficiency, and reliability for deployment in real-world cognitive radio systems. Advancing these techniques can address current limitations, enabling more robust performance under varying signal conditions and dynamic environments.
## 4 Results and Discussions
### Circularity Results  
#### 4.3.1 End-of-Life Usage of the Mix Designs  
To determine the end-of-life use applications of the novel concrete mix designs, crushed and repurposed concrete were used as a recycled concrete aggregate (RCA) in the same concrete mix. The RCA was obtained at laboratory scale by crushing the tested concrete cylinder specimens and sieving the aggregate mixture as per the AS 1141.11. The comparative results highlighted in Figure 5(b) signify that traditional concrete mix with RCA aggregates achieve the desired strength as compared to the control mix. The T2.5 and KFT concrete mix designs with RCA and textile and kraft fibres achieve 80-90% of the required strength in comparison with the control mix. These results signify that RCA from crushed sustainable concrete mix at the end of the life cycle can be used as a coarse aggregate in a normal 40 MPa concrete mix, justifying the circularity of the product. Also, these RCA can be used as an aggregate in low-stress concrete applications including paving concretes for footpaths. This is due to the presence of fibre materials within the aggregates that can reduce the thermal cracking in paving concretes.  
Figure 6: Comparison of compressive strength results of normal vs. RCA concrete specimens.
###### Abstract  
Given the increasing demand for biocompatible implant materials in regenerative engineering, novel surface modification techniques are essential to enhance tissue integration, durability, and corrosion resistance. This study investigates the application of plasma electrolytic oxidation (PEO), a high-voltage anodic oxidation technique, for the surface modification of magnesium (Mg) implants. The research emphasizes both functionality enhancement and process sustainability, adhering to green chemistry principles. A comprehensive analysis was conducted to evaluate the physicochemical and biological properties of the modified surfaces. The chemical structure of the coatings was characterized using Fourier-transform infrared spectroscopy (FT-IR) and atomic absorption spectroscopy (ASA). Surface morphology and composition were examined via scanning electron microscopy (SEM), while wettability was assessed through contact angle measurements. Additionally, biodegradation and biocorrosion studies were performed to evaluate stability, and cytotoxicity was tested using MG-63 human osteosarcoma cells. Results demonstrated that carefully optimized PEO process parameters, combined with appropriate electrolyte compositions, enabled the formation of MgO coatings with significantly enhanced stability, reduced biocorrosion, and improved biocompatibility. These findings indicate the potential of surface-modified magnesium implants for advanced biomedical applications.  
Keywords:biodegradable implants; Mg-based materials; PEO process; sustainable chemistry; green electrochemistry +
Footnote †: journal: Applied sciences
# Development of a Wideband Slotted Antenna Array with Low Profile and Low Sidelobe
## 2 Design of the Antenna Array
### Power Feeding Network
#### 2.2.2 The Complete Feeding Network  
A corporate-feed waveguide network is used in the 16 \(\times\) 16 slotted antenna array. The number of output ports in \(x\)- and \(y\)-direction of the feeding network are both 8, and each port in the feeding network excites a subarray that consists of four radiating slots. The complete feeding network is designed symmetric in both \(x\)- and \(y\)-direction, as shown in the left of Figure 8. Hence, it can be divided into four repeating quarters, as illustrated in the right of Figure 8. In order to reduce the SLL of the final antenna array, the feeding network is carefully designed, so that a Chebyshev power distribution can be realized at each coupling slot in \"Layer3\". The Chebyshev power distribution is described by [31]  
\[\sum_{i=1}^{N/2}l_{i}T_{2i-1}(x)=T_{N-1}(a_{0}x) \tag{2}\]  
Figure 7: Simulated phase balance and S-parameters of the 6 dB power divider.  
where \(I_{i}\) is the desired current in each output; \(N\) is the number of the outputs; and \(T(x)\) is the Chebyshev polynomial. The coefficient \(a_{0}\) can be calculated with  
\[a_{0}=\frac{1}{2}\Bigg{[}\left(R_{0}+\sqrt{R_{0}^{2}-1}\right)^{\frac{1}{N-1}}+ \left(R_{0}+\sqrt{R_{0}^{2}-1}\right)^{-\frac{1}{N-1}}\Bigg{]} \tag{3}\]  
where \(R_{0}\) can be calculated based on  
\[R_{dB}=20 log\frac{1}{R_{0}} \tag{4}\]  
In the designed feeding network, the port number \(N\) is 8 and the Chebyshev synthesis \(R_{dB}\) is expected to be \(-30\,\mathrm{dB}\). Hence, according to Equation (2), the calculated normalized current amplitude of each unit is 0.26, 0.52, 0.82, 1, 1, 0.82, 0.52, and 0.26, respectively. By calculating the amplitude distribution, various T-junctions with different power ratios are obtained by changing the offset \(m\) of the metal wall in the middle of the T-junction. The 6-level 1-64 power-weighted waveguide feeding network for the 16 \(\times\) 16 slotted cavity antenna array is presented in Figure 8, with the detailed power ratios being given as well. As shown in Figure 8, four types of T-junctions that have different power ratios are designed, and the corresponding power ratios are 7.31 dB, 6 dB, 1.83 dB, and 0 dB, respectively.
## 2 Materials and Methods
### Experimental Equipment Layout and Joint Geometry  
As depicted in Figure 1a, the experimental equipment mainly consists of a force-displacement acquisition system, a DIC system, and an AE system. The uniaxial compression test was performed on the WHY-300/10 microcomputer-controlled testing machine from Shanghai Hualong Company, which comprises a loading device and a computer. The loading mode was displacement-controlled at a rate of 0.005 mm/s. The DIC system comprises a CCD camera of Hikvision Corporation from China, a light source, and a computer, featuring a speckle acquisition rate of 15 frames per second. The AE system consists of two acoustic emission probes, two preamplifiers, a PAC-II acoustic emission receiving device, and a display. The AE signal threshold was set to 40 dB. When the loading head applies force to the specimen, the acoustic emission signals and speckle images are collected synchronously, and the collection is stopped after the specimen fails. Additionally, before collecting the speckle images, speckles need to be created on the specimen. Observing Figure 1b, it can be seen that the specimen has dimensions of 140 mm \(\times\) 70 mm \(\times\) 30 mm, with a 50-50 ratio of hard and soft composite rock. The specimen's defects consist of two unparallel joints, ensuring that the inclination angle of the rock bridge between the joints is 45\({}^{\circ}\) and the length is 20 mm. It is assumed that the inclination angle of joint 1 is \(\partial\), and the inclination angle of joint 2 is \(\beta\). Therefore, a specimen named S-\(\partial\)-\(\beta\) represents a soft-hard composite unparallel joint rock specimen with a lower joint inclination angle of \(\partial\) and an upper joint inclination angle of \(\beta\).
## 3 Results
### Uncertainty Analysis under Different Noise Conditions
#### 3.2.4 \(\lambda\rho\)  
The ROC curves of \(\lambda\rho\) under different noise conditions (\(-20\) dB, \(-10\) dB and \(-7\) dB) are shown in Figure 15a-c, respectively. The ROC curves shift towards the random guess line with the increasing noise level. The evaluation metrics are given in Figure 15d-f. The precision is close to 0.8 and the other metrics are less than 0.7. The results in \(-10\) dB and \(-7\) dB (Figure 15e,f) are similar to the \(-20\) dB scenario.  
Figure 14: The AUC curves of the FF\({}_{\text{Smith}}\) in the different noise scenarios: \(-20\)dB, \(-10\) dB and \(-7\) dB.  
Figure 13: The ROCs of the FF\({}_{\text{Smith}}\) in the different noise scenarios: (**a**) \(-20\) dB, (**b**) \(-10\) dB, (**c**) \(-7\) dB. The metrics of the FF\({}_{\text{[PERSON]}}\) in the different noise scenarios: (**d**) \(-20\) dB, (**e**) \(-10\) dB, (**f**) \(-7\) dB.  
The comparison of the AUC curves in the scenarios where the noise is \(-20\) dB, \(-10\) dB and \(-7\) dB is shown in Figure 16. The performance decreases with increasing noise. The approximate ranges of the AUC are 0.6 to 0.7, 0.58 to 0.68 and 0.55 to 0.65 when the noise is \(-20\) dB (blue), \(-10\) dB (red) and \(-7\) dB (yellow), respectively.
## 4 Discussion
### Criteria for the Early Diagnosis of the Disease through the Analysis of Handwriting  
The analysis carried in this work suggests that a specific designed protocol, and the analysis of specific features, depending on the characteristics of the handwriting tasks, would provide clinicians with a useful tool for supporting the early clinical diagnosis of the disease. Our analysis suggests that a diagnostic protocol should:  
* Contain tasks characterized by different level of shape complexity, as those analyzed in this work. Indeed, reduced differences of performance (in terms of writing speed and acceleration) between simple and complex shape tasks would indicate the presence of the disease.
* Consider task performed with different writing conditions, such as freely and guided performed tasks, since the performance decay observed from free to guided conditions is informative for the early diagnosis. Here, we observed that, for patients with PD, performance decay between free and guided condition is greater for simple shape tasks than for complex shape tasks. For healthy subjects we observed the opposite, that is performance decay is greater for complex shape tasks than for simple shape tasks.
* Contain tasks aimed at testing the ability of patients in increasing handwriting size through the use of guiding dots. However, since we have observed that isochrony is preserved in the early stage of PD, the analysis has to be focused more on the percentage of stroke size increase, rather than other parameters, such as velocity and pressure, for identifying the signs of the disease in the early stage.
* Take into account that handwriting fluency is slightly affected by the disease in the early stage, and that normalized jerk values falling into a \"healthy range\" do not exclude the presence of the disease.
* Contain tasks involving the use of novel motor plan for drawing a simple known shape in different writing conditions, as those analyzed in this work. Indeed, since PD patients benefits from the execution of novel motor plan tasks in terms of response time and exerted handwriting pressure, a higher increase of exerted pressure when performing simple novel tasks in free condition would suggest the presence of the disease. Similarly, response time decrease or similar response time between free and guided conditions when drawing simple shapes by using a novel motor plan would suggest the presence of the disease.
## 5 Conclusions  
1. The study proves the correspondence of the skeletal maturity index SMI and cervical vertebral maturation stage CVMS and confirms the validity of the hypothesis tested within the longitudinal study: The pre-pubertal stage has the corresponding indexes SMI 1,2,3,4 and CVMS 1,2. The pubertal stage has the corresponding indexes SMI 5,6,7 and CVMS 3. The post-pubertal stage has the corresponding indexes SMI 8,9,10,11 and CVMS 4,5. The Cohen's kappa coefficient shows the existence of an almost perfect concordance in the case of both sexes (k = 0.84 for female and for male k = 0.85).
2. The validation of the hypothesis within the longitudinal study supports the idea of a possible clinical applicability of the CVMS indexes for estimating the skeletal age along the treatment, after starting the use of orthodontic appliances. The results obtained show that the method could be clinically useful, offering information about the biological stage in which the patient finds himself/herself, in order for the orthodontist to be able to evaluate the remaining growth over the period of the orthodontic treatment.
3. The comparison of the statistical data obtained in the two studies (transversal and longitudinal) showed with no exception better results within the longitudinal study, as a better concordance was found among the analyzed data.
4. The study shows that both SMI and CVMS indexes could be used in order to determine the biological moment in which the patient finds himself/herself. For estimating the skeletal age, the orthodontist may use, as a common practice, the lateral cephalogram, which spares the patient from an additional eradication necessary for a hand X-ray.  
Conceptualization, E.G. and E.T.; Methodology, E.I.; Software, A.R.H. and S.N., Validation, E.I., E.T. and S.M.J.; Formal analysis, E.G.; Investigation, E.G.; Resources, E.G.; Data curation, E.G. and E.I.; Writing--original draft preparation, E.G.; Writing--review and editing, S.N.; Visualization, A.R.H.; Supervision, E.I.; Project administration, S.M.J. and A.R.H. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study. The study was conducted in accordance with the Declaration of Helsinki, and approved by the Ethics Committee of \"Carol Davila\" University of Medicine and Pharmacy (protocol code PO-35-F-03, 12 December 2019).  
Not applicable.  
The authors declare no conflict of interest.
## 3 Problem Statement
### Congestion Detection  
The perception of network congestion by sending nodes is often inaccurate. In classic congestion control schemes such as Reno and NewReno, packet loss is considered a signal of congestion in the network. When the sending node discovers packet loss but there is no congestion in the network, these algorithms significantly reduce the congestion window, reduce the sending rate, and lead to a decrease in bandwidth utilization and throughput performance. This phenomenon is particularly evident in networks with high latency and high bandwidth. Tests have shown that in links with a bandwidth of 10 Gbps, the performance of NewReno and other solutions can be reduced by more than 90% with only 0.0049% packet loss, which is much lower than 1%.
## 5 Simulation Results
### Verification of Identification Model
#### 5.1.2 Cooling System  
The cooling system is affected by both the fuel and the refrigerant valve opening, so the cooling system can be viewed as a two-input single-output system. According to the nonlinear analysis in Section 2, the nonlinearity of the cooling system is very strong, so the Hammerstein model identification method proposed in Section 3 is used to identify the model of the cooling system. The input sequence shown in Figure 8a is applied to the MGT-CCP system to obtain the output data shown in Figure 8b. The model of the power supply system was identified using the first 3000 s of data. The identified Hammerstein model is as follows:  
\[\begin{array}{l}y_{t}-2.003y_{t-1}+0.9596y_{t-2}+0.1375y_{t-3}-0.09403y_{t-4} =[0.2851-1.846\times 10^{-5}]\overline{u}_{t-1}\\ +[0.0185\ -3.288\times 10^{-5}]\overline{u}_{t-2}+[-0.05676\,5.084\times 10^{-5}] \overline{u}_{t-3}+[-0.3084\,7.234\times 10^{-6}]\overline{u}_{t-4}.\end{array} \tag{24}\]  
Figure 6: Identification data (power generation system). (**a**) input command data; (**b**) output data.  
Figure 7: Estimated output and true output (power generation system).  
where \(\overline{u}=\left[\begin{array}{c}f_{1}(u_{1})\\ f_{2}(u_{2})\end{array}\right]=\left[\begin{array}{c}u_{1}-0.0019{u_{1}}^{2}\\ u_{2}-0.0108{u_{2}}^{2}\end{array}\right]\).  
The accuracy of the identification model is verified using the last 3000 s of the data of Figure 8. The verification results are shown in Figure 9. It can be seen that the identified Hammerstein model has high accuracy and can reflect the changing trend of the system.  
Figure 8: Identification data (cooling system). (**a**) input command data; (**b**) output data.  
Figure 9: Estimated output and true output (cooling system).
## 2 Mathematical Formulation
### Objective Function Structure  
The problem under study is addressed in this research from an economic perspective. The main idea of installing these devices is to minimize the expected operating cost of the network, which is mainly associated with the energy loss costs for a one-year period of operation (\(f_{1}\)), to which the annualized investments in D-STATCOMs (\(f_{2}\)) are added.  
\[f_{1}=C_{\text{{{{{K}}}}}{  
by constant power loads) [23]. However, this is typically represented by the product between voltages and trigonometric functions of their angles, as this allows evidencing the effect of the power balance constraints (which are presented later in this document) regarding variations in active or reactive power injection. In the case of the quantification of the investment costs of D-STATCOMs, as defined by Equation (2), this function was adapted from [19], where the authors presented different cubic functions to represent the costs of variable reactive power compensators based on power electronics for power system applications.  
The objective function corresponding to the object of minimization is defined in this research as the sum of the components \(f_{1}\) and \(f_{2}\), as presented in Equation (3) for the variable \(A_{f}\).  
\[\min A_{f}=f_{1}+f_{2}, \tag{3}\]  
where \(A_{f}\) is denoted as the objective function value to be minimized.  
**Remark 1**: _The structure of the objective function (3) is nonlinear and non-convex due to the following facts: (i) the component \(f_{1}\) is defined as a product between the continuous variables (voltages) and the trigonometric function of the voltage angles, and (ii) the component \(f_{2}\) is a cubic function defined with the expected sizes of the D-STATCOMs, which makes the final function value \(A_{f}\) a complex nonlinear objective function that requires advanced optimization techniques in order to obtain a solution._  
In this research, to solve the complex objective function regarding the installation and sizing of D-STATCOMs in distribution grids with radial or meshed structures, the GNDO approach is combined with the successive approximations power flow method. In addition, an improving stage based on the ORPF problem is implemented in order to obtain additional reductions in the final \(A_{f}\) by fixing the location of the D-STATCOMs determined via the GNDO approach.
## 3 Numerical Results and Discussion
The eigenvalues of the real part in Figure 9a are positive in the time period of t = 7490-7494 s and all values in Figure 9b are also positive, except the value of a small portion at t = 7484 s. The values of \((C_{nr})_{\text{osc}}\) are mostly positive; \((C_{nr})_{\text{osc}}\) is insufficient in oscillatory damping to induce the unstable Dutch roll and spiral modes. The eigenvalues of the real part in Figure 9c are negative. The roll mode is stable because the values of \((C_{lp})_{\text{osc}}\)are mostly small negatives to have some roll damping. Figure 4.3 Eigenvalues of lateral-directional modes of motion. (**a**) Eigenvalues of the Dutch roll mode; (**b**) Eigenvalues of the spiral mode; (**c**) Eigenvalues of the roll mode. Airlines care about the vertical plunging mode of motion, which is not considered in classical flight dynamics. According to [28], in vertical plunging motion, the damping term is mainly related to \(C_{z\ddot{z}}\). It may be possible to define the severity of plunging motion based on the vertical plunging equation of motion. For the present purpose, if the severity is defined by the lowest load factor developed, this transport aircraft developed \(-1.05\) g with \(\Delta\)h = 57.3 m (around t = 7483 s). The phugoid mode in Figure 8b has all positive real eigenvalues; this implies insufficient longitudinal oscillatory damping and virtual mass effects during sudden plunging motion. Thus, this transport does not have sufficient lateral-directional oscillatory damping. Therefore, it may be concluded that the plunging motion is more severe because of its unstable condition.