esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Background
### Continuous Wavelet Transform (CWT)  
A continuous wavelet transform (CWT) is a powerful time and frequency features analysis tool [32; 33]. CWT has the ability of localization decomposition using methods such as short-time Fourier transform (STFT). Moreover, the adjustable scale and translation parameter of the mother wavelet function enable it to decompose a signal with different resolutions [34]. The adjustment of the two parameters constitutes the family of the time-scale waveform, which can be described as:  
\[\psi_{a,b}(t)=\frac{1}{\sqrt{a}}\psi\bigg{(}\frac{t-b}{a}\bigg{)}. \tag{1}\]  
\(\psi\) is the analytic function, referred to as the mother wavelet function, in the continuous wavelet transform; \(a\) is the scale parameter; and \(b\) represents the translation parameter. Then, the continuous wavelet transform of the given signal \(x(t)\) is defined as:  
\[C(a,b)=\frac{1}{\sqrt{a}}\int_{-\infty}^{+\infty}x(t)\psi^{*}\bigg{(}\frac{t-b }{a}\bigg{)}dt. \tag{2}\]  
\(C(a,b)\) are the wavelet coefficients at scale \(a\) and translation \(b\), and \(\psi^{*}\) denotes the complex conjunction of \(\psi\).  
Due to the ability of a local analysis with high time and frequency resolution, the continuous wavelet transform can provide the hidden information of a signal that other analysis techniques fail to reveal [35]. In this paper, the CWT technique is utilized to extract time and frequency domain features through the approach of converting raw in-vehicle sensor signals to two-dimensional images as the input for the CNN model for anomaly detection.
## 2 Materials and Methods
### The Design of the Forward-Rotation Subsystem
\[\dot{V}_{3}=s_{3}\dot{s}_{3}=s_{3}\big{(}\gamma_{3}\dot{s}_{1}+ \gamma_{4}\dot{s}_{2}\big{)}=s_{3}\big{[}\gamma_{3}\big{(}\gamma_{1}\dot{e}_{ x_{u}}+\dot{e}_{v}\big{)}+\gamma_{4}\big{(}\gamma_{2}\dot{e}_{\theta}+\dot{e}_{w} \big{)}\big{]}=s_{3}\big{[}\gamma_{3}\big{(}\gamma_{1}\dot{e}_{x_{u}}+\dot{e} _{d}-\dot{v}\big{)}+\gamma_{4}\big{(}\gamma_{2}\dot{e}_{\theta}+\ddot{w}_{d} -\dot{w}\big{)}\big{]} \tag{34}\] \[=s_{3}\big{\{}\gamma_{3}\big{[}\gamma_{1}\dot{e}_{x_{u}}+\dot{v}_ {d}-f_{1}-\frac{m_{2}}{\Omega}\big{(}\tau_{eq1}+\tau_{eq2}+\tau_{sw}\big{)}-D _{1}\big{]}+\gamma_{3}\Big{[}\gamma_{2}\dot{e}_{\theta}+\dot{w}_{d}-f_{2}- \frac{1}{m_{2}}\big{(}\tau_{eq1}+\tau_{eq2}+\tau_{sw}\big{)}-D_{2}\big{]} \big{\}}\] \[=s_{3}\big{[}-\eta_{1}o(s_{3})\text{sgn}(s_{3})-\mu_{1}s_{3}^{2}+ \gamma_{1}\big{(}\dot{D}_{1}-D_{1})+\gamma_{2}\big{(}\dot{D}_{2}-D_{2}\big{)} \big{]}\leq-\eta_{1}o(s_{3})|s_{3}|-\mu_{1}s_{3}^{2}+|s_{3}|\Big{(}\gamma_{1} \Big{|}\ddot{D}_{1}\Big{|}+\gamma_{2}\Big{|}\ddot{D}_{2}\Big{|}\Big{)}\]  
By design \(\eta_{1}o(s_{3})>\gamma_{1}\Big{|}\widetilde{D}_{1}\Big{|}+\gamma_{2}\Big{|} \widetilde{D}_{2}\Big{|}\), the result of the following equation can be obtained. \[\dot{V}_{3}\leq-\eta_{1}s_{3}^{2}\leq-\frac{\eta_{1}}{2}V_{3} \tag{35}\]  
From Lemma 1 in [38], the following equation can be obtained. \[V_{3}(t)\leq e^{-\frac{\eta_{1}}{2}(t-t_{0})}V(t_{0}) \tag{36}\]  
It can be seen that the \(V_{3}(t)\) index converges to 0, and the rate of convergence depends on \(\eta_{1}\). As demonstrated by the preceding equation, the error state can attain the slip surface in a finite amount of time. Subsequently, the first layer of slip surfaces \(s_{1}\) and \(s_{2}\) can converge asymptotically to zero, leading to the convergence of both the rotational and forward velocities of WIPR to the desired values.
# Method to Predict Performances of PCB Silicone Conformal Coating under Thermal Aging
## 2 Materials and Methods  
### Conformal Coating Material Selection  
Two commercial silicone conformal coatings from Dow (named coating A and B) were selected to study the appearance of crack defects when PCB boards protected by those coatings are submitted to external stresses. Coatings were selected to be very different by intention regarding CTE values and mechanical properties (Table 1). Conformal coating A is harder, with higher scratch resistance benefits when handling PCB. Conformal coating B is softer with lower modulus and better deformability.
###### Abstract  
Network behavior analysis is an effective method to outline user requirements, and can extract user characteristics by constructing machine learning models. To protect the privacy of data, the shared information in the model is limited to non-directional network behavior information, such as online duration, traffic, etc., which also hides users' unconscious needs and habits. However, the value density of this type of information is low, and it is still unclear how much student performance is affected by online behavior; in addition there is a lack of methods for analyzing the correlation between non-directed online behavior and academic performance. In this article, we propose a model for analyzing the correlation between non-directed surfing behavior and academic performance based on user portraits. Different from the existing research, we mainly focus on the public student behavior information in the campus network system and conduct in-depth research on it. The experimental results show that online time and online traffic are negatively correlated with academic performance, respectively, and student'  
time, logout time, usage time, and usage flow. Although this kind of data is easy to obtain, the data structure is complex, the value density is low, and the increment is rapid, which is often ignored by people, and there is little research on this kind of data [6]. In fact, these data often contain a lot of hidden information related to learning and life. If we can analyze these data scientifically and effectively, and make reasonable use of the analysis results, it will play a great role in promoting the school's teaching management [7].  
This paper studies the influence of students' non-directional online behavior on learning and proposes an online behavior and score combined (OBSC) model based on the user portrait. Section 4 is used to extract the characteristics of the user's non-directional online behavior attributes, describes the user's online behavior preferences through statistical and cluster analysis, and determines whether the students tend to indulge in the Internet and bad online habits, to support the relevant teaching decisions or proceed with the corresponding educational intervention [8]. The fifth section of the paper uses a polynomial regression model based on the least square method to realize the correlation analysis and prediction of the user's academic performance.  
The main contributions of this paper are as follows:  
1. Introduce the related research work.
2. The concept of non-directional Internet behavior is put forward, and the user profile technology is used to analyze the user's Internet data.
3. The feature extraction of users' non-directional Internet behavior is carried out by cluster analysis.
4. The method of polynomial regression is proposed to predict students' academic performance, and the influence of non-directional Internet behavior on students' learning is analyzed.
## 1 Introduction
Due to their strength, machinability, and sustainable manufacturing demands, Al\({}_{3}\)BC/Al composites show promise for future-generation aerospace and automotive parts (airframes, propeller blades) [25]. Reinforcing graphene platelets (GNPs) uniformly in the Al matrix has been a decades-long challenge, which limits the development of graphene-reinforced high-strength Al-matrix composites. Recently, research by [PERSON] et al. successfully demonstrated the fabrication of Al\({}_{3}\)BC/Al composites using a liquid reaction (stir casting) from amorphous B and GNPs [20]. This approach can potentially overcome the hurdle of graphene dispersion and pave the way a new generation of high-performance Al-matrix composites [26]. Powder metallurgy (P/M) offers a solid-solid reaction to create a bimodal heterostructure in the Al-matrix composites, using ball milling and high-press sintering to achieve homogeneous dispersion of reinforcements in the matrix [27; 28; 29; 30; 31; 32; 33]. The key advantage of solid-solid (pressing and sintering) reactions is the ability to control the morphology, shape, and size of the reinforcing phases that evolve during both in situ and ex situ approaches [17; 34; 35; 36]. However, the solid-solid reaction path to develop in situ Al\({}_{3}\)BC/Al composites remain a challenge. [PERSON] et al. showed difficulty controlling microstructures with Al-MgB\({}_{2}\) powder reactions because multiple by-products, like AlB\({}_{2}\) and Al\({}_{4}\)C\({}_{3}\), often resulted [37]. The presence of intermediate products, like micron-sized Al\({}_{4}\)C\({}_{3}\), can significantly deteriorate the mechanical properties of Al\({}_{3}\)BC/Al composites [38]. Therefore, fabrication temperature and modulating the reaction products of Al\({}_{3}\)BC/Al composites are crucial to obtain the desired mechanical properties in these composites because of the effect of undesired reaction products. Accordingly, in this work, we focused on a straightforward method for fabricating Al\({}_{3}\)BC/Al composites using mechanical alloying (ball milling) combined with a solid-state reaction technique (pressing and sintering) by varying reaction time (3 to 7 h) at 1000 \({}^{\circ}\)C temperature to avoid unwanted byproducts with optimized mechanical properties.
# Effect of Aggregate Size on Recycled Aggregate Concrete under Equivalent Mortar Volume Mix Design
###### Abstract
In the EMV mix design, the residual mortar of RCA is considered as mortar, and the OA of RCA is considered as actual aggregate for mixture proportioning. However, these studies did not investigate the influence of OA size. In some publications [32,33,34,35], residual mortar content in excess of 50% was observed. Given that smaller RCA has higher residual mortar content, in practice, the small size of RCA may contain little or no OA. Theoretically, due to the presence of residual mortar, although the apparent particle size of RCA looks similar to that of NA, the actual size of OA is inevitably smaller than that of RCA. In particular, for RCA with high residual mortar content, the OA size becomes smaller. Therefore, in this study, in order to evaluate the effect of the OA size in RCA on properties of RAC, the particle size of RCA and OA was determined using the residual mortar removal method, respectively, and the fresh and hardened characteristics were investigated. As discussed above, the size of the aggregates is associated with the homogeneity and ITZ of the concrete material, affecting the mechanical strength in some way. For normal strength concrete, when aggregates with a maximum nominal size of 13-19 mm are used, the mechanical strength of concrete appears to be high. However, the existing literature does not consider the effect of OA in RCA. The significance of the paper lies primarily in the consideration of this parameter in the experimental course, so that the obtained results can be clues to improve the low performance of RAC.
# Analysis and Assessment of a Brushless DC Outrunner Motor for Agriculture Drones Using JMAG
## 1 Introduction
In [8], the electronic speed controller, motor and propeller are modeled analytically to evaluate the Field-Oriented Control (FOC) and trapezoidal performance in real drone scenarios. The nested PI controllers of the FOC commutations translate into higher computational requirements and electronic complexity in the ESC; while the out-performance of the FOC architecture is evident, the 1% efficiency improvement does not vindicate the superior costs and weight compared to the trapezoidal commutation in agriculture UAV. On the other hand, in [9], the design and electromagnetic analysis of a BLDC motor for a large-sizedmulti-rotor were conducted using ANSYS Maxwell software. The design requirements are defined by a systematic propulsion system assessment using analytical equations. Despite the progress made in BLDC motor analysis regarding drone applications, some challenges and limitations have been identified. These include a lack of BLDC motor analysis methodology in electric machine-dedicated simulation tools such as JMAG software, the use of numerical methods to select the optimal motor-propeller combination, and numerical efficiency assessment of propulsion system elements focused on UAV autonomy to ensure longer flying times in drone agriculture applications. The contributions of this work are as follows:  
* Electromagnetic performance assessment of a BLDC motor in agricultural drone applications using JMAG software. * Validation of the electronic speed controller circuit with trapezoidal commutation in JMAG. The reliability of the circuit is demonstrated by comparing the generated driving signals against commercial and in-house-built electronic speed controllers. * The use of Computational Fluid Dynamics and the finite element method (through JMAG), to assess the optimal motor-propeller combination. * Propulsion system design focused on multi-rotor autonomy. The propulsion system was implemented and tested in a large-sized UAV for agriculture. These contributions address the challenges of traditional propulsion system design and assessment, such as depending on large application-based drone databases and extensive experimental testing. The rest of this paper is organized as follows: Section 2 presents the design requirements and initial sizing of the agriculture UAV. Additionally, the performance of a commercial drone propeller is evaluated using Computational Fluid Dynamics (CFD). The methodology of electromagnetic analysis using JMAG, the analysis of a commercial BLDC motor, and the trapezoidal commutation technique are introduced in Section 3. In Section 4, the lithium-ion polymer (LiPo) battery characteristics for the application are defined, and through the computation of the efficiency of the BLDC motor, the drone autonomy in hover conditions is predicted. Finally, in Section 5, some conclusions and final comments are provided.
###### Abstract  
Clickable core-shell nanoparticles based on poly(styrene-co-divinylbenzene-co-vinylbenzylazide) have been synthesized via emulsion polymerization. The 38 nm sized particles have been swollen by divinylbenzene (DVB) and 2,2'-azobis(2-methylpropionitrile) (AlBN) and subsequently processed under high shear rates in a \(Z\)-shaped microchannel giving macroporous microclusters (100 \(\upmu\)m), through the reactive gelation process. The obtained clusters were post-functionalized by \"click-chemistry\" with propargyl-PEG-NHS-ester and propargylglicidyl ether, yielding epoxide or NHS-ester activated polymer supports for bioconjugation. Macroporous affinity materials for antibody capturing were produced by immobilizing recombinant _Staphylococcus aureus_ protein A on the polymeric support. Coupling chemistry exploiting thiol-epoxide ring-opening reactions with cysteine-containing protein A revealed up to three times higher binding capacities compared to the protein without cysteine. Despite the lower binding capacities compared to commercial affinity phases, the produced polymer-protein hybrids can serve as stationary phases for immunoglobulin affinity chromatography as the materials revealed superior intra-particle mass transports.  
macroporous Materials; click-chemistry; reactive gelation; protein immobilization; antibody purification Article
## 2 Approximated Lowpass Elliptic Response  
The elliptic or Cauer filter approximation is characterized by having ripples in both passband and stopband of the magnitude response. This results in a magnitude response that has a faster attenuation increase through that transition from passband to stopband than comparable order Butterworth, Chebyshev, or Inverse-Chebyshev responses [21]. A second-order elliptic lowpass filter can be realized using lowpass notch circuits described by the transfer function  
\[H(s)=k\frac{s^{2}+\omega_{z}^{2}}{s^{2}+s\frac{\omega_{0}}{Q}+\omega_{0}^{2}} \tag{5}\]  
where \(k\) is a gain factor, \(\omega_{0}\) is the pole frequency in rad/s, \(\omega_{z}\) is the zero frequency in rad/s, and \(Q\) is the quality factor. A second-order elliptic filter designed with a minimum attenuation of 50 dB in the stopband and 5 dB passband ripple is:  
\[E_{2}(s)=0.0031622\frac{s^{2}+108.0248}{s^{2}+0.4562s+0.607502} \tag{6}\]  
The magnitude response of Equation (6) is shown in Figure 1 as a solid line. Note that this response has the expected DC gain of \(-5\) dB and high frequency gain (HFG) of \(-50\) dB. To realize this magnitude response requires both poles and zeros to realize the ripples in stopband and passband. This differentiates the elliptic response from the Butterworth and Chebyshev responses which only require poles in their realization. To approximate this ripple behavior in stopband and passband using a fractional-order transfer function requires a form that can also realize fractional-order poles and zeros. A lowpass notch filter with a \((1+\alpha)\) order transfer function that achieves this is given by  
\[H_{1+\alpha}(s)=a_{4}\frac{a_{1}s^{1+\alpha}+1}{a_{2}s^{1+\alpha}+a_{3}s^{ \alpha}+1} \tag{7}\]  
This transfer function will have a notch shaped magnitude response with low and high frequency gains of \(a_{4}\) and \(a_{4}a_{1}/a_{2}\), respectively, and an attenuation from passband to stopband dependent on \(\alpha\). The magnitude expression for Equation (7) is given by  
\[|H_{1+\alpha}(j\omega)|=a_{4}\frac{\sqrt{a_{1}^{2}\omega^{2+2\alpha}+2a_{1} \omega^{1+\alpha}\cos\left(\frac{(1+\alpha)\pi}{2}\right)+1}}{\sqrt{a_{2}^{2} \omega^{2+2\alpha}+a_{3}^{2}\omega^{2\alpha}+2a_{2}\omega^{1+\alpha}\cos \left(\frac{(1+\alpha)\pi}{2}\right)+2a_{3}\omega^{\alpha}\cos\left(\frac{a \pi}{2}\right)+1}} \tag{8}\]  
where \(\omega\) is the frequency in rad/s.
# Determination of Cellulose Degree of Polymerization in Historical Papers with High Lignin Content
###### Abstract  
Determination of cellulose degree of polymerization (DP) is one of the most commonly used methods in paper degradation studies, performed either by a standardized method using viscometry (as average degree of polymerization (DPv)) or size-exclusion chromatography (SEC) (as weight average molecular mass (Mw)). Due to the insolubility of papers with high lignin content in cupitheylenediamine (CED), such as groundwood papers, viscometric determination is not possible; therefore, pretreatment is required to allow subsequent dissolution of the papers. In this study, the pretreatment of historical papers containing groundwood with sodium chlorite in acetic acid was investigated, which enables dissolution of the paper samples in CED and determination of the cellulose average degree of polymerization by viscometry (DPv). Kappa number was determined to estimate the lignin content in the papers. The suitability of SEC UV-VIS analysis for determination of Mw in papers with high lignin content had been verified before it was used as a comparative method for viscometry. Using SEC, changes in the weight average molecular mass (Mw) of cellulose tricarbonalite (CTC) derivative during delignification were evaluated. The results indicate that no significant depolymerization occurred in the selected samples under the studied delignification conditions, which was additionally confirmed with determination of monosaccharides by ion chromatography. The results of the Mw determinations by SEC and DPv by viscometry are in good correlation, justifying the use of viscometry after chlorite/acetic acid pretreatment to determine the cellulose average degree of polymerization in historical papers with high lignin content.  
weight average molecular mass; average degree of polymerization; cellulose; size-exclusion chromatography; viscometry; lignin; chlorite/acetic acid; historical papers +
Footnote †: journal:  
[PERSON]  
1 Library Research Department, National and University Library, Turjaska 1, 1000 Ljubljana, Slovenia 1  
[PERSON]  
2 Faculty of Chemistry and Chemical Technology, University of Ljubljana, Vetna Pto 113, 1001 Ljubljana, Slovenia; [EMAIL_ADDRESS] (I.K.); [EMAIL_ADDRESS] (I.K.C.)
## 3 Computational Modeling of the Retina
The authors presented an analysis resulting from the stimulation range and threshold of healthy retinal ON ganglion cells in the early stages of degeneration, which was compared to the currently used stimulation waveforms, and proposed an asymmetric biphasic current stimulation to subdue the spontaneous firing to allow for increased control over the ganglion cell firing patterns in the degenerate retina [88]. The development of a good prosthesis depends on the improvement of predictive models based on the natural signal flow in the retinal network and a better understanding of neural responses to electrical stimulation. Experimental evidence is available in the literature showing that spike timing is needed to explain neural computation, motivating the use of spiking neuron models. This requires detailed biophysical representations of neurons, which use the Hodgkin-Huxley (HH) model [120]. There has been a greater focus on modeling different visual processing pathways in terms of the biophysics of their neuronal activity rather than the construction of image sensors [35]. Recent retinal models simulate neural behaviors, their physiological operations, and reproduce individual neuronal functions or can be combined to replicate a network of neurons. It also considers object-sensitive cells as a function of ganglion cells based on the movement of objects in a scene and the product of self-movement (movements of head and eyes) [121]. Other computational models of retinal ganglion cells include asynchronous or event-controlled algorithms, where faster executions occur because of less wasted time in neuronal behavior calculations without consequent events [35]. Non-instantaneous synaptic interactions exploit the delay structure to speed up simulations, where they present a unique solution for processing spikes in a priority queue in a programmable algorithm [122; 123]. However, in hardware translation, buffers and transmission delays are introduced, which in turn removes the advantage it has in theoretical computing. These simulation tools aim to achieve a balance between speed efficiency, memory consumption, and precision in the numerical treatment of the system of equations, as well as create a hardware conversion driven by a very large scale integrated (VLSI) circuit. Several models are expressed using a system of ODEs and continue in differential form without further transformation [124]. All these reasons make mapping into hardware difficult but study into the development of models is still ongoing based on the old mechanistic and integrated computational models to thus provide frameworks to facilitate understanding of disease mechanisms.