esa-sceva/satcom-chunk-collection huggingface dataset:
# Internal Flow Prediction in Arbitrary Shaped Channel Using Stream-Wise Bidirectional LSTM
###### Abstract  
Deep learning (DL) methods have become the trend in predicting feasible solutions in a shorter time compared with traditional computational fluid dynamics (CFD) approaches. Recent studies have stacked numerous convolutional layers to extract high-level feature maps, which are then used for the analysis of various shapes under differing conditions. However, these applications only deal with predicting the flow around the objects located near the center of the domain, whereas most fluid-transport-related phenomena are associated with internal flows, such as pipe flows or air flows inside transportation vehicle engines. Hence, to broaden the scope of the DL approach in CFD, we introduced a stream-wise bidirectional (SB)-LSTM module that generates a better latent space from the internal fluid region by additionally extracting lateral connection features. To evaluate the effectiveness of the proposed method, we compared the results obtained using SB-LSTM to those of the encoder-decoder(ED) model and the U-Net model, as well as with the results when not using it. When SB-LSTM was applied, in the qualitative comparison, it effectively addressed the issue of erratic fluctuations in the predicted field values. Furthermore, in terms of quantitative evaluation, the mean relative error (MRE) for the x-component of velocity, y-component of velocity, and pressure was reduced by at least 2.7%, 4.7%, and 15%, respectively, compared to the absence of the SB-LSTM module. Furthermore, through a comparison of the calculation time, it was found that our approach did not undermine the superiority of the neural network's computational acceleration effect.  
deep learning (DL); computational fluid dynamics (CFD); convolutional neural network (CNN); encoder-decoder (ED); recurrent neural network (RNN); long short-term memory (LSTM) +
Footnote †: journal: Medical Computing  
Accepted: 17 October 2023  
Published: 19 October 2023
# Status of Pure Electric Vehicle Power Train Technology and Future Prospects
## 4 Electric Propulsion
### Induction Motor Control  
The three major control system for induction motors are:  
1. Variable-Voltage Variable-Frequency (VVVF) Control  
It adopts with constant voltage control for frequencies below the rated frequency, and variable-frequency control with constant rated voltage for frequencies beyond the rated frequency. For very low frequencies, voltage is boosted to recoup the difference between the applied voltage and induced EMF.  
From the Figure 11, it can be observed that there are three operating regions:  
1. Below the rated speed, the motor delivers rated torque in constant torque region.
2. The slip is increased gradually to the maximum value at constant-power region with constant stator current and the motor runs with the rated power.
3. The slip remains constant in the reduced power region where there is decrement in stator current and the torque capability declines with the square of the speed.
2. Field-Oriented Control (FOC) FOC for the induction motor drive can be implemented by:  
1. The direct FOC, also known by the direct vector control, identifies the rotor flux linkage instantaneously by measuring the air-gap flux from stator voltage or current.
2. The indirect FOC, also known as indirect vector control, has been widely used in the induction motor drive for driving the EVs. This technique does not need to identify the rotor flux linkage.
3. Direct Torque Control (DTC)  
The DTC provides the equivalent performance for the induction motor drive. This system selects the switching modes of the voltage-fed PWM inverter directly to controlling the stator flux linkage and the torque application of the induction machine in electric vehicles.  
Most common motors used as the propulsion unit in EVs are IM because the design is simple and stable, with greater control and lower cost.  
Figure 11: Capabilities of operating VVVF controlled induction motor [78].
# Development and Evaluation of Nano-Silica Sustainable Concrete
## 3 Results  
### Slump/Flow  
The slump and flow tests were performed in the lab at three different times, which were immediately, thirty minutes, and sixty minutes after the concrete mixing process, as shown in Table 2. The specific surface of nano-silica's particles was large due to its small size, which increases the water demand of the concrete mixes. Therefore, as the nano-silica dosage increased from one mixture to another, the Megaflow 1000 polycarbonate superplasticizer dosage was increased to maintain the same water/cement ratio (0.36) in all the mixtures.  
Comparing the initial slump and flow test results of (M2 and M3) to (M1) and (M5 and M6) to (M4) showed that adding nano-silica reduced the slump and the flow spread of the mixtures, which in consequence reduced the workability of the concrete. Furthermore, comparing the slump and flow test results after 30 and 60 min to the initial slump and flow test results showed that using nano-silica reduced the setting time, because the nano-silica accelerated the hydration process. Moreover, the 30% GGBS concrete mixtures (M5 and M6) required more high range water reducer (HRWR) superplasticizer dosages as the nano-silica dosage increased from one mixture to another to maintain the water/cement ratio, compared to the 70% GGBS concrete mixtures (M2 and M3). Therefore, the 30% GGBS mixtures (M5 and M6) had higher water demand in comparison to the 70% GGBS mixtures (M2 and M3). Finally, the mixtures that contain a 2% dosage of nano-silica (M3 and M6) had a significant slump and flow reduction especially after sixty minutes compared to the mixtures that contain a 1% dosage of nano-silica (M2 and M4). Thus, as the dosage of nano-silica increased, the workability of the concrete decreased.
## 3 Measurement Results  
Figure 2d illustrates the fabricated antenna. The S\({}_{11}\) was measured at the Universitat Teknologi Petronas (UTP) antenna measurement facility using a network analyzer (Keysight PNA-X N5242A), which was calibrated using the calibration module (NA4691B) from Keysight. For on-body measurement, a flat human tissue model was used with the same dimensions that were used in the simulation. A gap similar to the assumed air-gap in the simulations of the distance (d) of 10 mm was created between the antenna and body surface. This was achieved using multiple layers of denim textiles to create a layer similar to the thickness of clothes and the air-gap between clothes and the body. This air-gap is also necessary for safety, which is briefly discussed by [PERSON] et al. in [28]. Furthermore, to study the effect of the body on the antenna characteristics, the fabricated antenna was tested on various locations on-body. It can be noticed that the body affects the impedance BW and radiation characteristics in two bands, while the antenna showed good matching within the desired frequency range. Table 3 illustrates the performance of the proposed antenna.
###### Abstract  
The development of prosthetic arms has increased in recent years, particularly with the growth of 3D printing technologies. However, one of the main weaknesses of 3D-printed prosthetics is the prosthetic socket, which commonly presents a generic adjustable design that may produce discomfort. In fact, the socket has always been a part that has frequently caused discomfort in traditionally manufactured prosthetics and, consequently, high rejection rates. Studies about improving the socket component in traditional and 3D-printed upper limb prostheses are scarce. Advancements in 3D printing and 3D scanning will offer a high potential to improve the design and manufacturing of 3D-printed sockets. Thus, to propose better designs and manufacturing protocols, this paper presents a questionnaire to assess the needs of upper limb prosthetics users or potential users, as well as a survey-based study with 18 respondents. The results reveal that users prioritize breathability and low cost, a stable fixing system, products without the need for shape adjustments, a light weight and comfort regarding the products they require. The results of this study provide insights into the key characteristics that sockets should accomplish according to users' needs that are applicable to 3D-printed sockets and traditionally manufactured sockets, and they contribute to improving their design and manufacturing.  
3D printing; 3D scanning; prosthetics; questionnaire; socket; upper limb Article Identifying Users' Needs to Design and Manufacture 3D-printed Upper Limb Sockets: A Survey-Based Study.
## 4 Design and Implementation
### OOK Modulation  
OOK stands for On-Off Keying Modulation. In this modulation technique, logic bits, i.e., 1 and 0, are converted into on and off-duty cycles; this is one of the most popular techniques to provide data communication due to its ease of implementation [23]. Pulses in OOK modulation of a VLC system represent On and Off states of light. Thus, an OOK modulation can be achieved simply by converting the received data into on-off states of light. However, to achieve communication in the visible light spectrum, special care has to be taken to avoid flickering while performing data transmission. Thus, flickering issues can be tackled by having higher frequencies of On-Off cycles and using a suitable bit encoding technique like Manchester Encoding. However, in OCC-based communication, the cycles cannot be directly decoded because the frame rate of a standard camera is lower than the operational flicker-free frequency of the transmitter. Thus, the rolling shutter phenomenon is used to address the issue of high-frequency On-Off Cycles. The captured image is the result of serial activation of the array of micro photo-sensors of the camera. This allows the recording of transmitter states at different pixels at different times; which results in an image containing bands/stripes/rolls. The color of these stripes represents received bits. Dark stripes are for logic 0, and bright stripes are for logic 1. The width of dark and bright stripes will be equal, however, for manchester encoded bits there could be maximum two consecutive 0 s or two 1 s which will have twice the width of one 0 or one 1 bit. For example, if the width of dark and bright bands is 10 pixels individually, then manchester encoded bit pattern '100101' will have widths like 10, 20, 10, 10, 10 pixels.
## 1 Current Role of CCTA in Clinical Practice and Guidelines
### Acute Chest Pain  
In the emergency department setting, CCTA may help rule out acute coronary syndrome (ACS) in patients with low-to-intermediate pre-test probability (PTP) due to its high negative predictive value. The 2014 American Heart Association/American College of Cardiology (AHA/ACC) guideline for the management of patients with non-ST-elevation acute coronary syndrome does not provide specific recommendations about CCTA [11]. However, CCTA is described as a more rapid and cost-effective diagnostic exam than stress myocardial perfusion imaging in low-risk patients with chest pain. In front of low-to-moderate risk of CAD and unconvincing results with cardiac troponin and/or electrocardiogram (ECG), the most recent European Society of Cardiology (ESC) guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation propose CCTA (Class IA) as a substitute to coronagraphy for ruling out ACS [12]. Furthermore, these recommendations advise performing CCTA (Class IB) for patients with persistent suspicion of ACS who have no return of chest pain, normal troponin values, and without electrocardiographic alterations before choosing an invasive strategy (Table 1) [12].
# Path Planning Strategy for Implementing a Machine Control System in Grader Operations
## 3 Path Generation Algorithm for Graders
### Work Path Generation Algorithm
#### 3.3.2 Set the Safety Line Distance  
Because of the nature of road construction earthworks, road edge lines often involve steep drop-offs. According to heuristic investigations, it is common for graders to either extend the blade slightly beyond the outer boundary line or align the blade edge with the outer boundary line. However, such practices can pose a risk of equipment overturning [30; 31; 32]. To address this issue, the concept of a safety line was introduced (Figure 6). The safety line represents the distance at which the work was conducted away from the outer boundary line of the road. The safety line can be set according to the user's preference, and its implementation helps prevent the overturning of the equipment.
## 3 Results
### Changes of PRI, SIF and GPP for Corn and Soybean
#### 3.1.2 Seasonal Changes of PRI, SIF and GPP  
Figure 3 displays the measured data for two consecutive growth periods (one is for corn; the other is for soybean) at the US-Ne2 site. The observed data at the US-Ne3 site can be found in Figure S1. It can be shown that for both corn and soybean, \(SIF_{t}\) and GPP followed similar seasonal patterns. PRI showed an obvious seasonal shift, which may also contain information about energy allocation changes. In order to reduce the influences of chlorophyll content and canopy structure on PRI, we only used measured data at the growth peak period with NDVI greater than 0.70 for subsequent analysis.
# Strategies for Deploying a Sensor Network to Explore Planetary Lava Tubes
## 1 Introduction  
The evidence of a possible entrance to an underlying lava tube was first detected from the 10 m/pixel-resolution Terrain Camera (TC) aboard the Japanese lunar orbiter Selenological and Engineering Explorer (SELENE) in 2009 [1]. The TC data detected three features, namely the Marius Hill Hole (MHH), Mare Tranquillitatis Hole (MTH), and Mare Ingenii Hole (MIH), as shown in Figure 1. The feature Marius Hill Hole (MHH) is a vertical hole in the middle part of a rille (303.3\({}^{\circ}\) E, 14.2\({}^{\circ}\) N, \(-\)1.65 km elevation from the lunar mean radius of 1737.4 km) in the Marius Hills region, a region rich in prominent volcanic features [2]. The hole is 65 m in diameter with an estimated depth of 90 m [1]. The hole is very similar to openings called \"skylights\" in lava tubes on the Earth and Mars and differs from normal impact craters in the vicinity. The Mare Tranquillitatis Hole (MTH) is located at 33.2\({}^{\circ}\) E, 8.3\({}^{\circ}\) N, \(-\)0.77 km elevation, 350 km from the Apollo 11 landing site. It is nearly twice the diameter of the Marius Hills feature and is roughly circular. The hole was estimated to be over 100 m deep from shadow measurements. The Mare Ingenii Hole (MIH) is located at 166.0\({}^{\circ}\) E, 35.6\({}^{\circ}\) S, \(-\)3.62 km elevation. It has a slightly irregular shape (rounded triangle) with a long-axis length of 140 m (east-west) and a short-axis length of 110 m (north-south) in the TC data.
## 5 Results
### Evaluation of CORES With and Without Emotional Aspects  
To evaluate the performance of the CORES system with and without emotional aspects, we conducted a 36 h test to collect sufficient data. The test showed a statistically significant difference in user satisfaction, with a \(p\)-value of 0.001. Participants were divided into two groups. Group A interacted with a traditional recommendation engine that did not consider emotions, while Group B used CORES, which integrated emotional insights into its recommendations.  
Figure 13 shows a comparison of CORES' performance with and without emotional integration, focusing on key metrics such as users' satisfaction, retention rates, emotional responses, and recommendation accuracy. The results clearly demonstrate that CORES, with emotional integration, enhances recommendation accuracy and improves users' satisfaction, engagement, and retention. These findings highlight the value of emotional intelligence in enhancing online shopping experiences.  
Unlike traditional shopping apps like Amazon, which mainly rely on past behaviors such as purchase histories, CORES offers a personalized recommendation system by considering the user's current emotional state. It dynamically adjusts its recommendations  
Figure 13: Performance comparison with/without emotion in VR. User satisfaction scores (0–6) vs. performance metrics as percentages (0–100).  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Method** & **Dataset Size** & **Accuracy (\%)** & **Precision (\%)** & **Recall (\%)** & **F1 Score (\%)** \\ \hline \multirow{6}{*}{TF-WordVect} & 50 & 94.0 & 100 & 91.4 & 95.7 \\  & 100 & 87.0 & 94.3 & 83.3 & 83.3 \\  & 150 & 92.7 & 96.9 & 92.9 & 94.9 \\  & 200 & 90.5 & 94.2 & 92.9 & 93.5 \\  & 250 & 92.0 & 100 & 88.6 & 94.3 \\  & 300 & 92.0 & **100** & 88.6 & 94.3 \\ \hline \multirow{6}{*}{Proposed} & 50 & 97.0 & 75.0 & 100 & 85.7 \\  & 100 & 96.0 & 71.0 & 100 & 83.7 \\ \cline{1-1}  & 150 & 96.7 & 72.2 & 100 & 83.9 \\ \cline{1-1}  & 200 & 95.5 & 66.7 & 100 & 80,0 \\ \cline{1-1}  & 250 & 95.6 & 70.3 & 100 & 82.5 \\ \cline{1-1}  & 300 & **96.7** & 70.6 & **100** & **82.8** \\ \hline \hline \end{tabular}
\end{table}
Table 5: _Cont._based on emotional context, time, and location. Moreover, CORES integrates social context by adapting recommendations according to the emotional states of the user's friends. By continuously analyzing users' emotions and monitoring interactions, CORES fine-tunes the shopping experience in real time to enhance users' satisfaction and engagement. This customization includes comprehensive product explanation, detailed material descriptions, emotional feedback, prompt responses to inquiries, and reminder emails with transparent pricing to effectively address users' concerns.
# The Recent Advancement in Unmanned Aerial Vehicle Tracking Antenna: A Review
## 3 Antenna Overview
### Aperture Antenna
#### 3.8.1 Inverted F Antenna  
The appetite for an inverted F antenna surged with an increased demand for light-weight and simple yet effective antennas in many commercial modern communication networks. The Bluetooth technology uses the inverted-F antenna. The pattern of radiation of the inverted-F antenna is omnidirectional in nature with a bandwidth of 250 MHz. Another good use of this type of antenna is its effectiveness for indoor communication [73; 74; 75]. The inverted-F arrays can be easily fabricated using microstrip materials in which conductors usually copper can be etched out using a suitable machine. Since the antenna is domiciled in the omnidirectional domain, it may not be suitable for highly directional UAV tracking antennas with long-range communication.
## 3 Results
### Mathematical Data Processing and Acetic Acid Concentration Determination
To solve a system and provide the acetic acid concentration, the algorithm needs about 5 s (depending on the hardware specifics of the machine on which it is operated and the complexity of the resulting system). The algorithm was tested on the raw data coming from mixtures of butanol and acetic acid at different concentrations, and it was found that the system has a limit of detection (LOD) for acetic acid of 30 ppb and provided accurate responses for acetic acid concentrations up to 30 ppm. To prove the initial supposition that resistance measured for each sensor, when they are exposed to an atmosphere containing both volatiles, will be a linear combination of the resistance variation for each gas, a test was conducted by exposing the two sensors different mixtures of acetic acid and butanol in a closed container. Tested mixtures and the results obtained are reported in Table 2.  
From the data obtained it can be assumed that, even if BIOS1 and BIOS2 sensors' response to air containing both target analyte and interferent is not a perfect linear combination of the responses of each sensor towards each gas, it can be safely approximated using the linear model with minimal deviation between experimental and calculated acetic acid concentration values. The algorithm has been integrated in the user interface software, called a BIOSENSOR Monitor. The BIOSENSOR Monitor recognizes the connection of the sensing array to the PC, identify which sensors are connected and in which slot and provides users with the data from each sensor both in numerical and graphical forms. If the sensors BIOS1 and BIOS2 are plugged in the board, the BIOSENSOR Monitor allows the user to read the raw resistance value provided by the sensors or, by pressing a button on its simple interface, to start the integrated algorithm, calculating and displaying the acetic acid concentration detected by the sensors.
# Performance of UAV-to-Ground FSO Communications with APD and Pointing Errors
## 2 System and Channel Modeling
### System Modeling
The thermal noise variance can be given by [22]  
\[\sigma_{th}^{2}=\frac{4k_{B}TB_{e}}{R_{L}}, \tag{6}\]  
where \(k_{B}\), \(T\), \(R_{L}\) are the Boltzmann constant, Rx's equivalent temperature in degrees Kelvin, and APD's load resistance, respectively. Moreover, as illustrated in Figure 2, the Rx lens accumulates the transmitted optical signal beam, which is projected onto the Rx plane's surface. The incoming optical signal then converges onto the surface of the APD's area. In this process, in addition to the desired optical signal, the background noise from the scattered sunlight is also added to the receiver. Therefore, because of the undesired background, the noise variance is obtained as  
\[\sigma_{bg}^{2}=2 eGFB_{e}\eta P_{b}, \tag{7}\]  
where \(P_{b}=\frac{\pi\
u^{2}}{4}B_{0}N_{b}(\lambda)\theta_{FOV}^{2}=AB_{0}N_{b}( \lambda)\theta_{FOV}^{2}\) represents the background power, which is generated by extended sources (e.g., the sky), \(r\) is the Rx lens radius, \(B_{0}\) is the optical filter bandwidth at the Rx (\(\upmu\)m), \(N_{b}(\lambda)\) is the spectral radiance of the background radiations at the optical wavelength \(\lambda\) (Watt/cm\({}^{2}\)-\(\upmu\)m-srad), and \(\theta_{FOV}\) is the Rx's field-of-view (FOV) angle [15]. It is noted that \(A=\frac{\pi\
u^{2}}{4}\) is the lens area of the optical receiver (cm\({}^{2}\)). Finally, the electrical signal-to-noise ratio (SNR) at the APD receiver output can be instantaneously formulated as  
\[s(t)=P_{t}\big{\{}1+m\big{(}s_{I}(t)\cos(2\pi f_{c}t)-s_{Q}(t)\sin(2\pi f_{c}t) \big{)}\big{\}}, \tag{1}\]0  
\[s(t)=P_{t}\big{\{}1+m\big{(}s_{I}(t)\cos(2\pi f_{c}t)-s_{Q}(t)\sin(2\pi f_{c}t) \big{)}\big{\}}, \tag{1}\]1 Modeling of the received beam at the FSO Rx station in the presence of UAV’s fluctuations. where \(X\) denotes the instantaneous channel coefficient. Because the atmospheric turbulence causes the slow fading nature of the scintillation process in the FSO link, the average symbol error rate (SER) is one of metrics for evaluating the performance of the considered system that employs the SI-QAM modulation. SER can be defined as  
\[s(t)=P_{t}\big{\{}1+m\big{(}s_{I}(t)\cos(2\pi f_{c}t)-s_{Q}(t)\sin(2\pi f_{c}t) \big{)}\big{\}}, \tag{1}\]2  
where \(f_{X}(X)\) denotes the distribution of \(X\).
## 3 Results and Discussion  
### Foam Effect on Compressive Strength of Geopolymer  
Figure 5 presents the compressive strength and density of the foamed geopolymer at 7 and 28 days. In general, all compressive strength of the specimen increased with age. For the geopolymer control, the strength was 9.10 MPa at 7 days, and it rose 105% by age to the value of 18.69 MPa at 28 days. The development of geopolymer gels increases with the increase of curing time and affects the strength. The compressive strength tends to decrease at 7 days by 0.63 and 0.29 times from the control geopolymer when the geopolymer contains 40% and 60% foam, respectively. Different trends slightly occurred with the compressive strength, which tends to increase about 1.26 times, and then drop drastically by 0.41 times from the control geopolymer at 28 days. This increment may be due to the non-uniform distribution of being foamed while casting the sample into the mold. However, by introducing the porosity into the geopolymer, the compressive strength tends to decrease. The instability of the solid structure and the addition of air void as porosity was the reason for the strength reduction [23; 24].