esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Non-catalytic Biodiesel Synthesis by Supercritical Fluid Technology
### Single Step SCFs Processes for Non-catalytic Biodiesel Synthesis
#### 3.2.2 Supercritical Dimethyl Carbonate (scDMC)  
It has recently been demonstrated that biodiesel can be produced from triglycerides and dimethyl carbonate instead of methanol, in a non-catalytic process by using supercritical dimethyl carbonate (T\({}_{\mathrm{c}}\) = 274.9 \({}^{\circ}\)C, p\({}_{\mathrm{c}}\) = 4.6 MPa) [63, 64, 65]. In this way, triglycerides as well as fatty acids are successfully converted to fatty acid methyl esters (FAMEs). Besides, with this methodology another valuable compound, glycerol carbonate, is obtained as a secondary product, instead of the undesirable glycerol, and a weak acid, such as citramatic acid, as the main by-product (see Figure 3). Glycerol carbonate has a higher commercial value compared than glycerol and has a greater potential for industrial application [66]. Hence, this methodology could have a large impact on biodiesel economics as two high added value products are produced in a single-step reaction, leading to increases cost effectiveness, even if high temperatures and pressures are required. The FAMEs produced by this method are obtained at higher yields than with supercritical methanol, and satisfy the international standards for use as biodiesel fuel. For instance, up to a 97.4 wt% yield can be obtained for the scDMC method at 300 \({}^{\circ}\)C, 20 MPa, 20 min and a 42:1 molar ratio of dimethyl carbonate to oil [67]. The properties of the biodiesel produced by this method have been evaluated according to different international standards. Overall, the FAMEs from the scDMC method satisfied all the requirements for international biodiesel standards except the specification regarding oxidation stability, which is an important parameter for preventing deterioration. However, this problem could be diminished by the addition of an antioxidant or by using oils containing lower levels of unsaturated fatty acids [68].
## 3 Problem Statement and Formulations
### Graphical Formulation
#### 3.2.3 Nodes for Delivery Requests/Depots  
Nodes also serve to symbolize the OF requests, OE requests, and the depot, all of which receive empty containers. In analogy to the representation of an IF request, one node is introduced for each OF request. It specifies the continuous activities of _delivering_ an empty container to the shipper (Origin), packing the freight, and then moving the fully laden container to the terminal (Destination). The service time \(T_{i}\), time window \([a_{i},b_{i}]\), and travel cost \(C_{i}\) can also be determined using Formulas (1)-(4). An OE request is also expressed by a single node \(i\in N_{OE}\), which stands for offloading an empty container at the terminal within the time window \([a_{i},b_{i}]\). For node \(i\in N_{OE}\), both the service time \(T_{i}\) and the travel cost \(C_{i}\) are equal to 0.  
To model the truck's intermediate return to the depot to store emptied containers released by IF requests, we introduce an additional collection of nodes \(N_{IF}^{D}\), including \(C_{IF}\) depot duplicates. A visit to a node in \(N_{IF}^{D}\) as opposed to a node in \(N_{IF}^{P}\), results in depositing an empty container to the depot. Therefore, \(\alpha_{i}(i\in N_{IF}^{D})\) is set to +1. Evidently, the time window, service time, and travel cost associated with nodes in \(N_{IF}^{D}\) are the same to those of nodes in \(N_{IF}^{P}\).
## 4 Simulation Results and Discussion  
In this particular section, the system under study has undergone testing in the presence of a wind turbine across four distinct scenarios. The first scenario (1) is divided into two parts: firstly, an evaluation of the efficiency and adaptability of the DOSA for optimizing the FOPD-FOPID controller parameters takes place alongside a comparison with other algorithms such as MSA, PSO, ABC, and GTO. Secondly, various methods incorporating the proposed DOSA-FOPD-FOPID controller are utilized to compare performance including LFC and SMES based on a robust controller (Controller 1); LFC and SMES based on the MSA-PID controller (Controller 2); LFC based solely on the MSA-PID controller with SMES (Controller 3); and finally, LFC based on the MSA-PID controller without SMES (Controller 4). These comparisons are made while accounting for both load disruptions and wind turbine disruptions. In scenario (2), the proposed method is being compared to several other methods, namely Controller 1, Controller 2, Controller 3, and Controller 4. The aim is to evaluate its performance in handling load disruptions and wind turbine disruptions. Moving on to scenarios (3) and (4), the performance of the proposed method is assessed alongside the mentioned methods. In addition to load disruptions and wind turbine disruptions, these scenarios also consider uncertainties related to power system parameters and disruptions caused by renewable energy sources such as wind turbines.
## 3 Proposed Theoretical Method
### Soil Pressure Method Establishment
#### 3.3.1 Mechanical Analysis and Equations for Part I  
A slice element in part I is selected, and its stress is shown in Figure 5[17].  
\(z\) is the depth of the slice element, \(d_{z}\) is the thickness of the slice element, \(b_{s}\) is the upper surface width of the slice element, \(\delta_{1}\) is the enclosure structure-soil friction angle, \(\sigma\) is the vertical positive stress on the upper surface of the slice element, \((\sigma_{x}+d_{\sigma})\) is the vertical positive stress on the lower surface of the slice element, \(\sigma_{x1}\) is the lateral pressure of the enclosure structure on the soil, \(\tau_{1}\) is the shear stress of the enclosure structure on the soil and \(\tau_{1}=\sigma_{x1}\cdot\tan\delta_{1}\), T is the normal reaction stress acting on the slip plane, \(\tau\) is the frictional stress acting on the sliding plane and \(\tau=T\tan\varphi\), \(\gamma\) is the unit weight of soil, \(A\) is the area of the slice element, \(w\) is the weight of the slice element and \(w=\gamma\cdot A\), and \(q\) is the ground overload.  
According to the geometric relationship in Figure 4 and ignoring the second order and above, the following expression can be obtained:  
Figure 4: Calculation model of finite soil pressure.  
Figure 5: A slice element mechanical model of part I.  
\[\left\{\begin{array}{ll}b_{\rm s}&=\ \frac{h_{j}+b\tan\theta-z}{\tan\theta}\\ A&=\ b_{\rm s}\cdot d_{z}\end{array}\right. \tag{2}\]  
The mechanical equilibrium equation for the horizontal direction of the slice element is:  
\[\sigma_{\rm x1}dz+\tau\cdot cos\theta\cdot\frac{dz}{\sin\theta}\ =\ T\cdot\sin \theta\cdot\frac{dz}{\sin\theta} \tag{3}\]  
According to reference [3], \(\sigma_{\rm x1}=k_{\rm a}\cdot\sigma_{\rm z}\). \(k_{\rm a}\) is the Rankine active soil pressure coefficient.  
Simplifying Equation (3) yields:  
\[T\ =\ a_{1}\sigma_{\rm z} \tag{4}\]  
where \(a_{1}\ =\ \frac{k_{\rm a}\tan\theta}{(tanh\theta-\tan\varphi)}\).  
The vertical mechanical equilibrium equation for the slice element combined with Equation (4) is:  
\[\sigma_{\rm z}b_{\rm s}+\gamma A\ =\ (\sigma_{\rm z}+d\sigma)\cdot(b_{\rm s}- \frac{dz}{\tan\theta})+\tau_{\rm 1}dz+T\cdot cos\theta\cdot\frac{dz}{\sin \theta}+\tau\cdot\sin\theta\cdot\frac{dz}{\sin\theta} \tag{5}\]  
Solving Equation (5),  
\[\left\{\begin{array}{ll}\sigma_{z}\ =\ m_{1}(b\tan\theta+h_{j}-z)^{\sigma_{ \rm z}}+\frac{\gamma(b\tan\theta+h_{j}-z)}{a_{2}-1}\\ \sigma_{x1}\ =\ k_{\rm a}\sigma_{\rm z}\end{array}\right. \tag{6}\]  
where \(a_{2}=k_{\rm a}\tan\delta_{\rm t}\tan\theta+a_{1}\tan\theta+a_{1}-1\). \(m_{1}\) is the coefficient.  
When \(z=0\), \(\sigma_{\rm z}=q\), which is substituted into Equation (6), we obtain:  
\[m_{1}\ =\ \left[q-\frac{\gamma(b\tan\theta+h_{j})}{a_{2}-1}\right](b\tan \theta+h_{j})^{-a_{2}} \tag{7}\]  
The value range of \(z\) at slip surface CD is 0 to \(h_{j}\). When \(z=h_{j}\), the vertical stress of the BC surface can be obtained.  
\[\sigma_{z}=h_{j}\ =\ m_{1}(b\tan\theta)^{a_{2}}+\frac{\gamma b\tan\theta}{a_{2} -1} \tag{8}\]
# Cognitive Frequency-Hopping Waveform Design for Dual-Function MIMO Radar-Communications System
## 5 Simulation
### Target Detection Performance  
Figure 4a illustrates the detection probability offered by the proposed scheme versus the signal-to-noise ratio (SNR) for different iterations. The iteration process is run 20 times. All optimal waveforms are generated by the proposed two-step algorithm. The value of requested SNR increases as the probability increase for a particular number of iterations. The SNR decreases as the number of iterations increase for a certain detection probability. The detection performance offered by the proposed scheme improves as the number of iterations increases. Simulation results show that, on average, 20 iterations of the waveform optimization algorithm are required in order to achieve convergence of the target response estimation for a wide range of radar scenes.  
Figure 4b illustrates the ROC for the following four approaches while the value of received SNR equals to 8 dB. (1) \(4\times 4\) MIMO system based on conventional maximum a posterior (MAP) approach; (2) \(4\times 4\) MIMO system using the Kalman filtering [42]; (3) \(4\times 4\) MIMO system based on MI optimization (step 2) scheme; (4) \(4\times 4\) dual-function MIMO radar-communications system using the proposed scheme.  
The plot is run at the end of 24 iterations. For the probability of false alarm \(P_{fa}=0.005\), the of target detection probability generated by the proposed scheme is 0.95 as compared with 0.75 provided by the Kalman filtering method, 0.7 by MI optimization (step 2) criterion and 0.55 by conventional MAP approach. As the two-step scheme can use the temporal correlation of target characteristic during the radar scan interval, the dual-function MIMO system constantly adapts transmit mode to suit the dynamic radar scene. Furthermore, the successive target returns are considered as independent of each other. The property guarantees that information about the radar scene is learned at each instant of reception. In this case, the detection performance offered by the proposed scheme is best.
# Increasing the Insertion Loss of Sonic Crystal Noise Barriers with Helmholtz Resonators
## 4 SCNB Scatterer with Two HRs
When the inner wall is rotated to \(\theta=180^{\circ}\), the surfaces of the HRs are reversed and the acoustic behavior of the SCNB changes drastically. The IL of the Bragg-BG changes by more than 30 dB when the wall is rotated from \(\theta=0^{\circ}\) to \(\theta=180^{\circ}\) and the resonance frequencies now shift to f = 534 Hz and f = 1520 Hz. Although both configurations are geometrically equivalent because their HRs have identical surfaces, the central frequencies of the HR resonances are different because of the different alignment of the cylinders with respect to the incident wave. As Figure 6 right shows, the IL reaches SPL = 40 dB in the Bragg-BG frequency range. In [27], the combination of concentric closed-cylinders and cylinders with HR gives numerical and experimental results with less than 20 dB in the Bragg-BG frequency range. Several settings of HRs scatterers have been tested numerically and experimentally in [23], including porous materials inside the cylinder, but none of the combinations brought more than 25 dB in the whole Bragg-BG frequency range. Thus, our proposal of a barrier with  
Figure 6: **(Left)** IL in color scale as a function of frequency for SCNB with scatterers with coupled-surface HRs as a function of the inner wall rotation angle. (**Right**) Cases \(\theta=0^{\circ}\) and \(\theta=180^{\circ}\) and SCNB-CC. resonators tuned at the edges of Bragg-BG offers a very significant increase in IL compared to other proposals in the literature. Since SC is not an isotropic material, the acoustic behavior of SCNB with other incidences may be considered. This approach is made considering that the noise source is far away enough, so when source is closer, it would be interesting analyze how the SCNB performs. Instead of rotating the separator of the two HR cavities, rotate the whole cylinder can be also a good choice. By doing this, each scatter will have two different degrees of freedom. Implementing automatic control according to different stimulus could also be an extremely complex and versatile system, with the adaptative ability to perform several cases. Another interesting prospect to study would be now explore periodical configurations and see how the resonant scatterer performs.
## 4 Discussion
The models would also benefit from the use of high-resolution parcellations that take into consideration local circuits and dynamics. A second extension is to study other states and other transitions than the ones explored here. For example, oscillatory states (such as beta or gamma) may occur as responses to sensory stimulation, slow-wave states occurring under anesthesia, or pathological states such as coma or minimal consciousness. To model such states, the procedure is the same as that outlined here: start with a spiking network model displaying these new states, then design a mean-field model that can capture this effect, and--finally--integrate the mean-field model on a large scale in TVB. We believe that these are interesting directions to explore and that the models proposed here will provide useful tools for this exploration. Conceptualization, J.S.G. and A.D.; methodology, J.S.G., M.S. and L.K. ; analysis and preparation of the figures, M.S. ; writing of the initial manuscript, A.D.; supervision, project administration and funding acquisition, A.D. All authors have discussed the results and agreed to the published version of the manuscript. **Funding:** Research supported by the CNRS and the European Union (Human Brain Project H2020-785907, H2020-945539). **Institutional Review Board Statement:** Not applicable. **Data Availability Statement:** The source code of all simulations shown in this article is available online. A repository is available in _Zenodo_[32], and the code can be run online using the simulation capabilities offered by the Human Brain Project's EBRAINS neuroscience research infrastructure ([[https://ebrains.eu](https://ebrains.eu)]([https://ebrains.eu](https://ebrains.eu)) and [[https://ebrains.eu/service/the-virtual-brain](https://ebrains.eu/service/the-virtual-brain)]([https://ebrains.eu/service/the-virtual-brain](https://ebrains.eu/service/the-virtual-brain)), accessed on 17 January 2023). **Acknowledgments:** We would like to thank [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON] for their help, support, and discussions. **Conflicts of Interest:** The authors declare no conflicts of interest.
# An Acoustic Way to Support Japanese Children's Effective English Learning in School Classrooms
###### Abstract  
In this paper, the importance of implementing good acoustic conditions in classrooms using sound amplification systems is investigated to support more effective English education for elementary school children. To date, the failure of educating English as a second language at Japanese schools has been demonstrated by poor English conversation ability of those who completed a compulsory six-year English language course at Japanese junior-high and high schools (age 12-18). To amend the situation, teaching English became compulsory at grade three (age 8-9) and above at most Japanese elementary schools in the 2020 academic year. We conducted acoustic measurements of two types of sound amplification systems, a pair of PC loudspeakers and another with a loudspeaker array, in a typical classroom at an elementary school in Japan. We also analysed English listening test results of 216 Japanese native children (age 11-12) who were learning English in their usual classes in Japan, to compare the effects of those two systems. Results of logistic regression analysis adjusted by the discrimination difficulty of word pairs demonstrated the statistically significant association between correct answer rate of the English tests and classroom acoustic factors. Although, on average, upgrading the sound amplification system had positive effects on the correct answer rate, it also had a negative impact when the word pairs had English phoneme contrasts that do not appear in Japanese phoneme structure. Combined with the acoustic measurements' results, it was also revealed that heterogeneous sound fields that depend on seat positions could be compensated using sound amplification systems with loudspeaker arrays. Our findings suggest that improvement of both acoustic quality and teaching methods is required for children to acquire English communication skills effectively in their classroom.  
classroom acoustics; second and foreign language education; hearing in children; impulse response +
Footnote †: journal: Applied Sciences
# The Potential of LEO Satellite-Based Opportunistic Navigation for High Dynamic Applications
## 4 Performance Characterization  
### Scenario Description  
The scenario consists of a high dynamic vehicle using IMU data, magnetometer data, and Iridium Doppler shift data.
# Solution of Orifice Hollow Cathode Plasma Model Equations by Means of Particle Swarm Optimization
## 2 Plasma Model of Hollow Cathode
### Definition and Assumptions  
The hollow cathode internal plasma volume is divided into three regions: the keeper region, represented by \"k\" (which includes the keeper orifice region and the cathode-keeper gap), the insert or emitting region, represented by \"e\", and the orifice region, represented by \"o\", as depicted in Figure 1. A set of conservation equations is written for each region (Section 2.3) to compute averaged plasma properties (0-D model). The modelled plasma consists of neutrals, singly charged ions and electrons. The unknown parameters are the electron temperatures (\(T_{e,e}\), \(T_{e,e}\), \(T_{e,k}\)), the plasma densities (\(n_{e,e}\), \(n_{e,o}\), \(n_{e,k}\)), the neutral densities (\(n_{n,e}\), \(n_{n,o}\), \(n_{n,k}\)), the effective emissionength (\(L_{eff}\)), the sheath potential (\(V_{p}\)), and the wall temperature of the emitter (\(T_{s}\)), the orifice (\(T_{w,o}\)) and the keeper (\(T_{w,k}\)).  
The main assumptions, in agreement with the norm for 0D models [5; 6; 9], are as follows:  
1. The heavy particles (ions and neutrals) are in a thermal equilibrium between each other and their temperature is assumed to be equal to the temperature of the wall, i.e., \(T_{ion}=T_{n}=T_{w}\);
2. A choked gas flow model is used in the orifice regions of both the cathode tube and the keeper;
3. A double sheath potential drop is recorded at the orifice entrance region; thus, a planar double sheath is modelled (Figure 1).  
The neutral flow through the cathode's insert, which is transitional, is not modelled as continuous and governed by the Poiseuille'saw, which is a well established assumption for 0D models [14]. Instead, the cathode internal pressure is computed by means of [PERSON] et al. formula [15].  
For all the simulations described in this paper, xenon is used as a propellant because it is widely used in EP devices. Particularly, the electron-neutral cross section has been updated in order to include only elastic collisions as suggested by [PERSON] et al. [14] and to take into account the most recent experimental data, a fit of which is proposed in ref. [13].
## 4 Experimental Results
### Mission Success Rate  
To evaluate the efficacy of the mission plan in response to user requests, this study employs the mission success rate, a key concept in mission analysis being utilized by the Korea Aerospace Research Institute (KARI) [45]. Equation (9) signifies the ratio of obtained profit to the total profit when successfully observing all targets. Equation (10) expresses the ratio of observed targets to the total targets requested by the user.  
\[\text{Mission success rate for profit }(\%)=\frac{\sum\sum\sum p_{i}x_{ijk}}{\sum p_{i}} \times 100 \tag{9}\]  
\[\text{Mission success rate for target observation }(\%)=\frac{\sum\sum\sum x_{ijk}}{|I|} \times 100 \tag{10}\]  
Figure 13a illustrates the mission success rates achieved with 40 satellites and 500 targets over a day, utilizing both the MDP and greedy algorithms. The MDP algorithm reached a 100% mission success rate at around 17:50, surpassing the greedy algorithm, which reached the same rate at around 23:50. The efficiency of the mission planning process is highlighted by MDP's ability to complete all missions in a shorter timeframe than greedy, despite having an identical number of targets and satellites. These findings are further detailed in Figure 13b, depicting outcomes when extending the mission planning period from 1 day to 7 days. Notably, MDP, after 4 days, attained a profit of 91.0% and target observation of 86.4%, whereas greedy achieved only 68.3% and 69.2%, respectively. Furthermore, considering the completion of a 7-day mission plan, MDP realized success rates of 95.2% and 92.4%, while greedy demonstrated a significantly lower success rate of 75.0% and 76.2%, revealing an approximately 20% difference in mission success rates.  
Upon examining the correlation between the number of observed targets and resulting profit, it becomes evident that while greedy consistently displays an increase in both metrics  
Figure 13: Analysis of mission success rate. (**a**) Case: 500 targets and 40 sats in 1-day; (**b**) case: 500 targets and 8 sats during 7 days.  
throughout all time periods, MDP consistently achieves a higher profit relative to the number of observed targets. Starting from the 4 th day onward in Figure 13b, the objective function value in the case of the greedy algorithm starts to fall below the target observation value. This observation underscores the clear alignment of MDP with the problem's objective function, emphasizing the prioritization of high-profit target observation. These data described in Figure 13 can serve as a valuable reference for analyzing the completion of user-requested missions within the available satellite resources during the mission planning phase. To summarize, the outcomes indicate that the quantity of observed targets and resulting profits depend on the number of satellites and the planning horizon. The efficacy of the MDP algorithm is demonstrated by its adept implementation of the problem's objective function. Employing the mission success rate as a metric proves instrumental in evaluating the efficiency of incorporating users' requests into the mission plan.