esa-sceva/satcom-chunk-collection huggingface dataset:
# Digital Twins in the Automotive Industry: The Road toward Physical-Digital Convergence
## 1 Introduction
### The Historical Background of the Digital Twin Technology  
The \"Digital Twin\" idea arose in 2002 when Challenge Advisory presented the idea from [PERSON] from the University of Michigan regarding contemporary technological developments. The presentation had to do with the development lifecycle management center regarding products. This presentation included all the core details relevant with the \"Digital Twin\" technology such as physical space, virtual space, and the exchange of relevant data and information between physical and virtual worlds. Even though the used terms have been altered since then, the basic idea has remained the same. Even though it is generally believed that the concept was first been presented in 2002, it has been well-known since the 1960s. NASA has been using basic similar technology ever since, for space programming. What they actually did was fabricate physical twins at their facilities to simulate the physical mechanical assemblies operating outside of the Earth's environment. A relevant case was setup in the case of Apollo 13 when it was placed in orbit [9].  
When Apollo 13 was launched in April 1970, it was statistically unthinkable that the crew would fight for their own survival when oxygen tanks malfunctioned midflight. It is one of the most well-known rescue missions attempted, while technicians on Earth tried to come up with a solution while being on the Earth. What turned the rescue mission into a success, however, was the fact a digital twin of the spaceship was set-up on Earth, which enabled ground crews and scientists to come-up with a rescue plan. However, nowadays,  
Figure 1: Digital twin fundamental technologies.  
such system layouts have apparently become virtual rather than physical. Figure 2 depicts a characteristic systemic layout of a digital twin [10, 11].  
Accordingly, the main contributions of this article are given as follows:  
* Describe the modus operandi of the Digital Twin.
* List published literature works about Digital Twin category applications, Digital Twin process functions, and Digital Twin application domains.
* Quote cases where Digital Twin technology is already applied in the automotive sector.
* Include suggestions about further applications in this domain such as the vehicle's meta-life as the tools that support this transition (i.e., IoT, AI, and ML) progress as well.
###### Abstract  
With the rapid development of artificial intelligence technology, the physics-informed neural network (PINN) has gradually emerged as an effective and potential method for solving N-S equations. The treatment of constraints is vital to the PINN prediction accuracy. Compared to soft constraints, hard constraints are advantageous for the avoidance of difficulties in guaranteeing definite conditions and determining penalty coefficients. However, the principles on the formulation of hard constraints of PINN currently remain to be formed, which hinders the application of PINN in engineering fields. In this study, hard-constraint-based PINN models are constructed for Couette flow, plate shear flow and stenotic/aneurysmal flow with curved geometries. Particular efforts have been devoted to assessing the impact of the model parameters of hard constraints, i.e., degree and scaling factor, on the prediction accuracy of PINN at different Reynolds numbers. The results show that the degree is the most important factor that influences the prediction accuracy, followed by the scaling factor. As for the N-S equations, the degree of hard constraints should be at least two, while the scaling factor is recommended to be maintained around 1.0. The outcomes of the present work are of reference value for the development of PINN methods in fluid mechanics.  
artificial intelligence; physics-informed neural network; hard constraint; Navier-Stokes equations; incompressible flow +
Footnote †: journal: Applied Sciences
# Binary Decision Support Using AHP: A Model for Alternative Analysis
###### Abstract
One key drawback arises when decision-makers provide judgments that lack complete consistency, particularly when more than three criteria exist; in such cases, the original non-linear BWM model sometimes yields multiple optimal solutions rather than a unique set of weights. Additionally, BWM requires experts to reach a consensus on the best and worst criteria. This process often challenges participants and sometimes fails to capture the diversity of expert opinions in complex environments [16]. Nevertheless, many researchers and practitioners continue to adopt the AHP as a leading decision support methodology because its structured pairwise comparison process effectively incorporates subjective preferences into decision-making [17]. [PERSON] et al. [18] emphasized that AHP requires at least two alternatives, which creates a challenge when decision-makers must choose between only two opposing options. To address this gap, we introduce Binary AHP, an adaptation of the traditional AHP methodology explicitly designed for binary decision-making scenarios. This model retains the structured, hierarchical approach of the AHP and enables decision-makers to systematically evaluate two opposing alternatives, such as yes/no choices. We demonstrate the practical application of Binary AHP in the Brazilian public sector, where agencies must determine whether a technological solution qualifies as an Information and Communication Technology (ICT) solution. This classification is critical in shaping the procurement processes, funding allocation, and regulatory compliance. The proposed model increases the consistency, transparency, and comparability in such classifications; reduces the subjective biases; and improves the decision reliability. The remainder of this article follows this structure: In Section 2, we present the foundations of the AHP method, addressing its hierarchical structure, the pairwise comparison process, and the mechanisms for evaluating the consistency of expert opinions. Section 3 describes the proposed Binary AHP model in detail, including the mechanism for inverting comparison matrices and the calculation of global priority vectors for both alternatives. Section 4 applies the case study to the Brazilian public administration context, covering the model structuring, issuance of expert opinions, analysis of inverted priority vectors, and the final classification of technological solutions. In Section 5, we offer a comparative analysis between Binary AHP and other multi-criteria methods, highlighting the advantages and limitations of the proposed model. Finally, Section 6 presents our conclusions, discusses the identified limitations, and suggests directions for future research.
# Influence of Quality of Mounting Process of RF Transistors on Their Thermal Parameters and Lifetime
## 5 Results of Measurements
Comparing these results with the results presented in Figure 14, it can be observed that the PCB, to which the considered transistors were mounted, ensured a more efficient heat removal to the surroundings than the heat sink shown in Figure 9 operating in the free cooling mode. This proves a very good design of the tested PCB in terms of its effective cooling. The statistical considerations presented in the further part of this article will show whether the changes in R\({}_{\rm th}\) depend on the number of void spaces in the area of the transistor soldering. Another interesting question is how, apart from the dissipated power P\({}_{\rm D}\), changes in the case temperature T\({}_{\rm C}\) are also affected by the voids [46]. From the temperature value distribution through the transistor cross-section (Figure 15), three temperature values were determined: T\({}_{\rm emp1}\), T\({}_{\rm min}\), and T\({}_{\rm emp2}\). For each value of the temperature thus measured, three R\({}_{\rm th}\) values are determined, respectively, denoted as R\({}_{\rm thT1}\), R\({}_{\rm thTmin}\), and R\({}_{\rm thT2}\). The distribution R\({}_{\rm th}\) along the cross-section of the BLC10G22 LS-240 PVT transistor is shown in Figure 16.  
The data presented in Figure 16 shows that the value of thermal resistance R\({}_{\rm th}\) undergoes significant changes depending on the point in the cross-section of the transistor case, where temperature T\({}_{\rm C}\) is determined. The highest values of the temperature described as T\({}_{1}\) were measured in the vicinity of the application of the supply voltage V\({}_{\rm DS}\). This is not important with the highest R\({}_{\rm thT1}\) value for each of the transistors in each module. In the middle of the transistor case, one can see a visible drop in temperature described as T\({}_{\rm min}\). In the vicinity of the output of the other transistor, an increase in temperature defined as T\({}_{2}\) was observed again. However, T\({}_{2}\) < T\({}_{1}\), hence also R\({}_{\rm thT2}\) < R\({}_{\rm thT1}\). Changes in the R\({}_{\rm th}\) value  
Figure 15: Method of determining the temperature values T\({}_{\rm emp1}\), T\({}_{\rm emp2}\), and T\({}_{\rm min}\) from the thermogram of the temperature distribution on the transistor case. determined for various points on the surface of the transistor case differed from each other by up to 10%.
# A Combined High and Low Cycle Fatigue Life Prediction Model for Wind Turbine Blades
###### Abstract  
A novel method is proposed for a combined high and low cycle fatigue (CCF) life prediction model based on Miner's rule, incorporating load interactions and coupled damage effects to evaluate the fatigue life of wind turbine blades under CCF loading. The method refines the CCF damage curve by modeling the complex damage evolution process under L-H loading and establishes a life prediction model linking low cycle fatigue (LCF) and high cycle fatigue (HCF) damage curves for more accurate predictions. Compared to Miner's rule, the M-H model, and the T-K model, the proposed approach demonstrates superior prediction accuracy, with results predominantly falling within a life factor of \(\pm\)1.5. To verify the model's practical applicability, finite element analysis (FEA) was performed on critical blade sections, reducing the prediction error to 4.3%. This method introduces a novel approach for evaluating the fatigue life of wind turbine blades with improved accuracy over existing methods.  
wind turbine blades; combined high low cycle fatigue; composite materials; damage mechanics; life prediction Article
## 3 Results and Discussion
### System Validation with Slaked Lime
#### 3.2.2 Application of the Thomas Model  
Figure S9 shows the results of the linearized Thomas model, as described by Equation(6), as a linear plot of \(\ln(\text{C}_{0}/\text{C}_{\text{t}}-1)\) against time, at various operational conditions. The Thomas parameters, calculated with linear fitting, are summarized in Table S5.  
The [PERSON] model assumptions, namely, pseudo-second-order adsorption kinetics and negligible external resistance during the mass transfer processes, appear to be satisfied for 0.10 and 0.14 g of PC [75 \({}^{\circ}\)C\(\_\)30 RH%] and 0.14 g of PC [75 \({}^{\circ}\)C\(\_\)45 RH%], as evidenced by their correlation coefficient values (R\({}^{2}\) > 0.95). In these FGD experiments, the results for the adsorption capacity parameter, \(q_{0}\), were found to be consistent with the values calculated by numerical integration of the experimental data. Indeed, the calculated \(q_{0}\) is slightly higher than the corresponding breakthrough sulfur capacity in Table 1, which was calculated using the experimental point until C/C0 = 0.9. In contrast, the fitting of the data for PC [160 \({}^{\circ}\)C\(\_\)30 RH%] yielded a relatively low R\({}^{2}\) value of 0.83, indicating that the [PERSON] model may not be as effective in this case.  
The satisfactory agreement between the experimental data and the theoretical [PERSON] model for the PC adsorbent at 75 \({}^{\circ}\)C provides further evidence that the experimental apparatus is suitable for FGD measurements. The following paragraph provides an interpretation of the deviation of the PC [160 \({}^{\circ}\)C\(\_\)30 RH%] experiment from the model-based PC characterization before and after the FGD process.
# Highly Doped Phosphate Glass Fibers for Compact Lasers and Amplifiers: A Review
## 4 CW Single-Frequency Phosphate Fiber Lasers and Amplifiers
### Er and Yb/Er Co-Doped Single-Frequency Phosphate Fiber Lasers  
The first single-frequency phosphate fiber laser emitting at 1.5 \(\upmu\)m was reported in 2003 [77], with an output power of 100 mW and a very narrow linewidth of less than 2 kHz. It was a DBR fiber laser based on an heavily Yb\({}^{3+}\)/Er\({}^{3+}\) co-doped fiber (3 wt % of Yb\({}^{3+}\) and 2 wt % of Er\({}^{3+}\)) that displays very high optical gain per unit length of up to 5 dB/cm. The laser cavity was established by using two spectrally narrow passive FBGs that were fusion spliced to a 2 cm-long piece of active fiber.  
In 2013 [78] a monolithic all-phosphate glass fiber laser was reported, with a laser cavity obtained by inscribing a FBG directly into an heavily Yb\({}^{3+}\)/Er\({}^{3+}\) co-doped phosphate fiber (8 wt % of Yb\({}_{2}\)O\({}_{3}\) and 1 wt % of Er\({}_{2}\)O\({}_{3}\)) by using a femtosecond laser. Avoiding hybrid splices between phosphate and silica based fibers allowed for improving the laser stability and reducing the cavity loss. An output power of 550 mW was demonstrated with a slope efficiency of 12%.  
Power scaling of a single-frequency fiber laser emitting at 1.5 \(\upmu\)m was investigated in 2005 [79] by using a DC heavily Yb\({}^{3+}\)/Er\({}^{3+}\) co-doped phosphate fiber, cladding-pumped by multi-mode laser diodes at 976 nm. 1.6 W of single-longitudinal mode output power was reported from a 5.5 cm length of fiber, although the slope efficiency was limited at 5%.  
The main results obtained with highly RE-doped CW single-frequency phosphate fiber lasers are summarized in Table 3.
## 3 Methods and Model Setup
### Methods
#### 3.1.1 Continuity Equation  
In geodynamics, the major rock units (such as the mantle and crust) are considered to be continuous geologic media. The model assumes these geologic media to be incompressible conditions where the material point density does not vary with time:  
\[\frac{D_{\rho}}{D_{t}}=\frac{\partial_{\rho}}{\partial_{t}}+v_{i}\frac{ \partial_{\rho}}{\partial x_{i}}=0 \tag{1}\]  
\(\frac{D_{\rho}}{D_{t}}\) is the substantive time derivative of density for a moving Lagrangian point, \(\frac{\partial_{\rho}}{\partial t}\) is the time derivative of density for the same location's immobile Eulerian point, \(v_{i}\) is the velocity components.  
The incompressible continuity equation can be used for the cases when temperature and pressure do not change greatly and the total volume of the medium does not change. The 2D incompressible continuity equation of mass conservation is:  
\[\frac{\partial v_{x}}{\partial_{x}}+\frac{\partial v_{y}}{\partial_{y}}=0 \tag{2}\]  
\(v_{x}\), \(v_{y}\) are components parallel to the respective coordinate axes of the velocity vector \(\overset{\rightarrow}{v}\).
# Route Availability as a Communication Quality Metric of a Mobile Ad Hoc Network
## 5 Evaluation of the RA Calculation Method and Verification of Usefulness of RA
### Usefulness of RA as a QoS Metric
The fact that there was a negative linear correlation between RA and packet loss rate, as shown in Figure 10, indicates that packet loss was caused mostly by disconnections. This also means that packet loss in the network can be monitored by observing RA. Figure 10 shows that the packet loss rate for the case where the average number of hops was 2 or more is higher than that for the case where the average number of hops was 2 or fewer. The reason for this can be that a rise in the number of hops increases transmission delay, which in turn increases packet loss. Although a change in transmission delay due to a change in the average number of hops affects the relationship between RA and packet loss rate, its effect on this relationship is smaller than the effect of disconnections. Figure 11 looks at how the choice of routing protocol affects the relationship between RA and packet loss rate. It shows that the choice of routing protocol scarcely affects this relationship. This is most likely because nodes moved so slowly that differences between the two routing protocols did not manifest themselves. Although some routes' disconnections remain undetected with our RA calculation method for OLSR, the effect of this is small because this property is not much different from that of AODV. Figure 11: Relationship between RA and packet loss rate (when the routing protocol was varied). Figure 10: Relationship between RA and packet loss rate (when the number of hops was varied). Figure 12 shows how video quality affects the relationship between RA and throughput. It shows that there is a positive linear correlation between RA and throughput and that the throughput increases in such a way that it reaches the total bit rate of the reference video when RA = 100. This means that if the total bit rate of the video can be obtained and the transmission bit rate is constant, the network throughput can be estimated from RA. However, if the total bit rate of the video to be transmitted cannot be obtained, the maximum throughput when RA = 100 cannot be determined; thus, the actual network throughput cannot be estimated from RA. The above results indicate that RA is correlated to packet loss rate and to throughput, and thus is useful as a QoS metric. Packet loss rate and throughput cannot be determined unless feedback information from the destination node is available. In contrast, RA can be determined by the source node alone. Therefore, the network status can be monitored without adding any extra traffic load to the network.
###### Abstract  
This study is to evaluate a novel Quantum Molecular Resonance energy device as a laparoscopic bipolar vessel sealer. The majority of conventional bipolar energy-based vessel sealing devices utilize energy at frequencies between 300 kHz and 500 kHz. The use of such frequencies has disadvantages including unintended damage to surrounding tissues and excessive surgical smoke production. Here, we developed a bipolar energy source using Quantum Molecular Resonance (QMR) energy of 4-64 MHz and combined this into a laparoscopic vessel sealer. We investigate the microscopic tissue effect and surgeon's experiences of the laparoscopic bipolar vessel sealer using a novel QMR energy source through animal experiments. QMR energy sources showed higher sealing success rates (100% vs. 66.7%) and a higher burst pressure (963 mmHg vs. 802 mmHg) of the sealed vessels compared to LigaSureTM. Histological analysis showed less vessel wall injury in the QMR energy source (55.0% vs. 73.9%). In the laparoscopic setting experiments, compared to LigaSureTM, QMR energy sources showed statistically significantly less smoke formation (\(p=0.014\)), less tissue carbonization (\(p=0.013\)), and less stickiness (\(p=0.044\)) during sealing tissues. A novel QMR energy source for a laparoscopic bipolar vessel sealer could produce a better sealing performance and less surrounding tissue damage.  
Keywords:QMR; surgical energy device; vessel sealing technologies; laparoscopic surgery; surgical smoke; quantum molecular resonance +
Footnote †: journal: Applied
# Automated Anomaly Detection and Causal Analysis for Civil Aviation Using QAR Data
## 6 Experimental Evaluations  
The data for the experiments were extracted from the approach phase of 487 real-world flights of the same aircraft type. The number of unbalanced training sets and those that were balanced by the Borderline-SMOTE algorithm are shown in Table 6. Both the training and testing data were preprocessed and used for model training and validation. The same testing set is used to compare the experimental results.
# Stacked-GRU Based Power System Transient Stability Assessment Method
## 4 Case Studies
### Discussion
#### 4.2.2 Performance Comparison of Different Models  
Compared with long-short term memory (LSTM) [20], GRU replaces LSTM's forget gate and input gate with update gate which is equivalent to combining cell state and hidden layer state. Fewer parameters and simpler structure make it easier to train GRU. Experiments show that the effect of GRU is slightly stronger than or equivalent to LSTM on most tasks. The transient stability adaptive assessment method constructed by using 20 LSTM classifiers in reference [18] requires more training  
Figure 6: (**a**) The relationship between ART and number of layers; (**b**) \(\delta\) sensitivity analysis.  
parameters than 10 times the amount of model parameters built by parameter sharing in 3-layers stacked-GRU, so the computational resources of LSTM required are very large. Therefore, the model proposed in this paper adopts stacked-GRU.  
The intelligent assessment process of single-layer GRU, 3-layer stacked-GRU, and LSTM is compared in order to further verify that the proposed model has the advantage of high accuracy and lower model complexity. The test conditions of the three models are set to be equal to Section 4.2.1, the assessment results are shown in Figure 7.  
As can be seen from the Figure 7 and Table 1, the GRU and LSTM have the same assessment performance. The three models can correctly identify all the test sets in the fourth round of assessment, and the stacked-GRU has reached nearly 100% assessment in the first round of assessment and it's assessment result is ART = 1.08, it's assessment speed is greatly improved compared to that in a past paper [18], ART = 1.448. Meanwhile, the simulation also shows that stacked-GRU has stronger feature extraction capability than GRU and LSTM which results in achieving shorter assessment time.
Electronics_**2015**, \(4\), 37-58; doi:10.3390/electronics4010037  
_electriconics_  
**ISSN 2079-9292**  
www.mdpi.com/journal/electronics  
_Article_  
**On the Impact of Building Attenuation Models in VANET Simulations of Urban Scenarios**  
**[PERSON] 1,*, [PERSON] 2, [PERSON] 3 and**  
**[PERSON] 1**  
\({}^{1}\) Department of Network Engineering, Universitat Politecnica de Catalunya (UPC), C. Jordi  
Girona 1-3, Barcelona 08034, Spain; E-Mail: [EMAIL_ADDRESS]  
\({}^{2}\) Faculty of Informatics, Autonomic University of Sinaloa (UAS), De los Deportes Avenue and  
Leonismo Internacional, Mazatlan 82107, Mexico; E-Mail: [EMAIL_ADDRESS]  
\({}^{3}\) Department of Electronics, Telecommunications and Networks, Escuela Politecnica Nacional (EPN),  
Ladron de Guevara E11 253, Quito 170413, Ecuador; E-Mail: [EMAIL_ADDRESS]  
* Author to whom correspondence should be addressed; E-Mail: [EMAIL_ADDRESS];  
Tel.: +34-93-401-7041.  
Academic Editor: [PERSON]  
_Received: 29 October 2014 / Accepted: 29 December 2014 / Published: 8 January 2015_  
Buildings are important elements of cities for VANETs, since these obstacles may attenuate communications between vehicles. Consequently, the impact of buildings has to be considered as part of the attenuation model in VANET simulations of urban scenarios. However, the more elaborated the model, the more information needs to be processed during the simulation, which implies longer processing times. This complexity in simulations is not always worth it, because simplified channel models occasionally offer very accurate results. We compare three approaches to model the impact of buildings in the channel model of simulated VANETs in two urban scenarios. The simulation results for our evaluation scenarios of a traffic-efficiency application indicate that modeling the influence of buildings in urban areas as the total absence of communication between vehicles gives similar results to modeling such influence in a more realistic fashion and could be considered a conservative bound in the performance metrics.  
**Keywords:** vehicular _ad hoc_ networks; building attenuation models; propagation models; VANETs