esa-sceva/satcom-chunk-collection huggingface dataset:
# Enhancing Ignition Reliability with Tail-Groove Strut Designs in Cavity-Based Combustors
## 2 Materials and Methods  
### Numerical Model  
Figure 1 displays the detailed geometric structure applied to model the flow field in the afterburner, which contains the cavity flame holder and struts. The air flows through a rectangular combustor with dimensions of 160 mm (height) by 180 mm (width), while the length of the combustor is 800 mm. As depicted in Figure 1, an asymmetric cavity configuration is employed in the model. The struts are obliquely located in front of the cavity, with an incline angle of \(15^{\circ}\) and tail width of 30 mm. The igniter was arranged at the top of the cavity at the \(Z=0\) mm cross-section, extending 2 mm into the combustion chamber. The TDH20-1 igniter, with an 18 mm diameter, discharged at 5 Hz, storing 20 J of energy with a 15% electrical efficiency. Fuel injection was carried out using Danfoss nozzles with a flow coefficient of 6.0, positioned symmetrically at \(Z=\pm 40\) mm.  
In this paper, with all other structural parameters held constant, this study primarily investigated the impact of the novel strut on combustion performance. The tail-groove strut is denoted by \"_L_D_\", where \"_L_\" denotes the concave groove's length and \"_D_\" represents its width.
# Design and Implementation of Inverse Kinematics and Motion Monitoring System for 6 DoF Platform
## 1 Introduction
The majority of simulators have been designed based on the 6 DoF structure of the Stewart platform [5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17], which uses linear actuators to achieve a 6 DoF overall movement. However, the need to use six linear actuators is expensive. Therefore, this work proposes a six-axis crank arm mechanism for motion systems. There is no formal literature about the design and implementation of an actual crank arm mechanism platform. As in [18], this work's design was based on DIY methods to create a simple model. Limiting the range of movement through the error correction method achieves an effect similar to an integrator. In order to improve the movement stroke of the platform, this study investigated the crank arm motion platform with a monitoring system, in order to propose an inverse kinematics design for virtual cylinders. In addition, a motion monitoring system is proposed for affordable measurement of the platform. For affordability, low-cost sensors are utilized. The software offers functions such as sampling settings, impulse response display, real-time display of measured values, and log file reading and sending. To the best of our knowledge, the ideas we mention have not been presented in previously published papers [1; 1; 1; 12; 13; 14; 15; 16; 17; 18]. As a result, this paper presents some new ideas on the implementation of motion control systems, including an adjustable speed control system and a middle-distance stroke control system. Related measuring instruments, such as a touch panel, an industrial computer, professional wiring harnesses, sensors, jigs, and auxiliary appliances, are placed in a self-designed waterproof storage box to facilitate portability and operation at different venues. Validated through experiments, the proposed algorithm can control different attitudes, human-machine interface operations, network packet reading, and command receiving of the platform and can achieve 6 DoF control and monitoring.
## 2 Validation of FLAC Modeling on Wave Transmission across Rock Joints
### Normally Incident \(S_{y}\) Wave Transmission through a Single Joint  
In order to verify the capability of FLAC in modeling Sv wave transmission, in this section, normally incident Sv wave transmission across a single joint is studied. The model size is also 500 m \(\times\) 500 m, and the joint is horizontally located at Z = 250 m. Non-reflection viscous boundaries are placed at the upper and lower boundaries to avoid wave reflections from the artificial boundaries. The left and right boundaries are fixed in the Z direction. A half-cycle sinusoidal incident stress pulse with amplitude 1.01772 \(\times\) 10\({}^{7}\) Pa (to make sure that the velocity amplitude is 1.0 m/s) and frequency 50 Hz is normally applied at the bottom boundary. The physico-mechanical properties of the rock matrix are the same as those in Table 1. In this model, the incident and transmitted measure point are located at (X, Z) = (250, 50) and (250, 450) of Figure 1, respectively, as well as in Section 2.1.  
Figure 2: Relations between transmission coefficient \(T_{1P}\) and normalized joint stiffness \(K\) for normally incident P wave transmission across a single joint. FLAC3D: three dimensions of the Fast Lagrangian Analysis of Continua  
The FLAC results and analytical solutions are compared in Figure 2. The horizontal coordinate is normalized joint stiffness \(K\). The vertical coordinate is the magnitude of transmission coefficient across a single joint for Sv wave incidence \(T_{1S}\), which is defined as:  
\[T_{1S}=\max|\upsilon_{TS}|/\max|\upsilon_{IS}| \tag{4}\]  
where \(\upsilon_{IS}\) is the particle velocity of incident P wave, \(\upsilon_{TS}\) is the particle velocity of transmitted P wave. From Figure 3, it can be found that \(T_{1S}\) from the FLAC results agrees well with the analytical solutions. Therefore, FLAC is applicable to study Sv wave transmission.
# Satellite-Based Sea Ice Navigation for Prydz Bay, East Antarctica
## Materials
### Meteorological Data  
Meteorological data used in this study included 3-hourly atmospheric forecasts of mean sea level pressure (MSLP), near-surface winds from the Antarctic Mesoscale Prediction System (AMPS), and daily air temperature from an automatic weather station (AWS) in Zhongshan Station. AMPS data are available at a grid size of 15 km with high quality [18] and were validated for the Antarctic [19]. This dataset has been used to support wind forecasting and air operations, both inter- and intracontinental, especially in rescues and emergency situations as well as scientific field campaigns and activities. The MSLP and surface wind data reveal information about the expected weather system that will prevail over the ice regime at the time when the vessel enters it. The decision to acquire fine-resolution SAR data for ice navigation is based on this forecast. Daily air temperature is used to estimate the growing thickness of land-fast using a simple thermodynamic model.
# MQC-MB: Multiphoton Quantum Communication Using Multiple-Beam Concept in Free Space Optical Channel
## 4 The Implementation of MQC-MB
### Initial Phase
#### 4.1.3 Step 3: Preparation of FSO Terminals and Quantum Channel  
The quantum multiple-beam channel with TRx input and RXs output is constituted. The terminals of the sender and receiver are integrated with multiple lenses that function as the producers and collectors of the multiple laser beams. A laser diode is used at the transmitter and the output is divided so that each signal transmits the same value of power and uses the same wavelength. It can be noted that different wavelengths can be used to transmit the signals using a different number of laser diodes and avalanche photodiodes [40].
# Nanomaterials-Based Ion-Imprinted Electrochemical Sensors for Heavy Metal Ions Detection: A Review
## 2 Preparation of IIPs
### Preparation Principle of HMIIECSs  
ECSs are a kind of device based on the electrochemical properties of the analytes, which convert their chemical amounts into electrical signals for sensing and detection [51]. They are a combination of electrical analysis technology and sensing technology. As an important means of analysis and detection, ECSs have aroused extensive interest in recent years due to its advantages such as high sensitivity, good selectivity, easy operation, strong anti-interference, suitable for miniaturization and real-time online detection [52]. ECS mainly consists of a recognition system and a conduction system [53]. The recognition system mainly selectively reacts with the measured substance and converts the resulting chemical signals into current, resistance, potential and other signals, while the conduction system accepts the signals and converts them into readable ones that can be analyzed by computers [54]. As is shown in Figure 2, a three-electrode system is generally used in the construction of ECSs, including working electrodes (WE), reference electrodes (RE) and counter electrodes (CE) [53]. The WE is very important since it influences the electrochemical sensitivity due to the redox reaction between the electrode material and the electrolyte [55]. Recently, various modified electrodes have become the focus of research since the surface functionalization of the WE can greatly improve the work efficiency, especially those modified with IIPs [6].  
The detection principle of IIECSs is to combine IIT with an electrochemical detection method (Shown in Figure 2). The polymer prepared by the imprinting technology is used as the sensitive element and then modified to the electrode surface in various methods. When the IIPs bind to the ions in the solution, the electrochemical signal will change with the solution concentration. The response signals are finally detected and analyzed so as to detect the target ions. Generally, the selectivity of IIPs is used to determine HMIs based on the classical potentiometry and voltammetry. In the potentiometric method, IIPs replace the classical ionic groups used in ion selective electrodes (ISEs), and IIPs NPs-based HMI-ISEs have commenced a new era in the design of a new generation of potentiometric sensors, which have unique selectivity for the corresponding ions and a very low detection limit of \(10^{-8}\)-\(10^{-10}\) M [56]. Whereas in voltammetry, the role of IIPs is to selectively accumulate HMIs and these IIPs-modified electrodes exhibit much higher selectivity owing to their affinity for the specific size, charge, and coordination geometry of the target ions, and gain continued interest because of their high selectivity, low limit of detection (LOD), high accuracy, short analysis time, simple preparation and minimal sample pretreatment [6].
## 3 Results and Discussion
### Qualitative Comparison  
This section provides a qualitative analysis of network performance, focusing primarily on the effectiveness of plate recognition. Due to space limitations, we will only showcase the recognition results of the U-Net network, which has slightly higher plate recognition accuracy compared to PSPNet and DeepLab V3+. Figures 8 and 9 display recognition outcomes in various scenarios, featuring different types of dinnerware (bowls and plates) in various states (clean or not clean).  
In the first scenario, which is relatively simple and contains only a single bowl in a clean state, the comparison between the annotated image and the original shows that the U-Net network can accurately identify the position of the bowl and precisely determine its status. Although the annotated image is not a perfect circle, the U-Net network still accurately recognizes the contour of the bowl. This result demonstrates the competent performance of the U-Net network in plate recognition tasks.  
The second scenario is more complex, containing two targets: a plate and a bowl, with the plate being clean and the bowl not. Here, the U-Net network accurately identifies the positions of both the plate and bowl. Although it does not precisely determine the state of the bowl, the recognition is still accurate (not clean) based on the principle of area dominance. Notably, even when the plate's color closely matches the background, the U-Net network can still accurately identify the plate and achieve an ideal recognition result. Some misidentification of bowl pixels may relate to an imbalance in the number of bowls and plates in the training samples. Overall, the U-Net network demonstrates commendable recognition performance in complex scenarios.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Name of the Network** & **MIOU (\%)** & **MPA (\%)** \\ \hline U-Net & 68.64 & 78.21 \\ PSPNet & 63.72 & 75.66 \\ DeepLabV3+ & 65.51 & 77.64 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparison of recognition accuracy.  
Figure 8: Simple scenario.
## 4 Experiments and Results
### Experimental Results and Analysis
#### 4.5.1 Comparison of Evaluation Metrics' Results on DDR Dataset
These experimental results demonstrate that MLNet exhibits superior segmentation performance compared to the other seven advanced methods. The consistent superiority of MLNet across various evaluation metrics and lesion types confirms its effectiveness in accurately segmenting DR lesions.
# Optimization of a Centrifugal Compressor Using the Design of Experiment Technique
## 6 Results and Discussions
### Response Surface for Finding the Optimal Geometry
Results are derived for three different rotational speeds. The design point rotational speed is shown by \(N\) and other rotational speeds are 75%\(N\) and 1.25%\(N\). At the design point the optimized model shows 3.0% and 11.0% improvement in efficiency and pressure ratio respectively which are substantial. The range of the optimized design is not falling off toward choke as is often the case when a new design gives greater design point performance but at the expense of range. Range improvement near surge must be determined by means of an unsteady simulation [27] of the entire compressor or by experiment; however the current results show no operating range deterioration in comparison with operating points at low and high mass flow rates. At the lower mass flow rates the improvement in pressure ratio decreases in all rotational speeds. The isentropic efficiency curves show in lower mass flow rates, the original case has higher value in comparison to optimized case and by increasing the mass flow rate the performance of optimized impeller increases (Figure 19). \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Function** & **Reference** & **Optimum** & **A** & **B** & **C** & **D** & **E** & **F** \\ \hline \(\hat{y}_{Pr}\) & 2.245 & 2.336 & 0.091 & \(-1.000\) & 0.313 & \(-1.000\) & 1.000 & 1.000 \\ \(\hat{y}_{\eta}\) & 85.15\% & 85.54\% & 1.000 & 1.000 & \(-1.000\) & 1.000 & \(-0.616\) & 0.838 \\ \(\hat{y}_{f}\) & 1.00 & 0.972 & \(-0.535\) & 1.000 & 1.000 & \(-1.000\) & 0.939 & 1.000 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Optimum value for objective functions. Figure 17: Isentropic efficiency versus pressure ratio for design space. Different aspects of flow behavior can be studied to compare the original case with the optimized one. As the effect of blade angle distribution and splitter parameters on the flow streamline at different span are shown before, the pressure contour at meridional plane are investigated here. Figure 20 compares the optimized and the original case. On the left, the meridional curves are shown simultaneously as well as the leading edge positions of the main blade and splitter. The optimized geometry prepares the wider passage for flow at its mid way and it helps the fluid to diffuse more smoothly. The pressure contours at the meridional planes are shown at the design point. Beside the fact that pressure rise in optimized case is much more than the original case, it can be seen that in the original case the pressure difference between hub and shroud along the line which perpendicular to mid span is rather large. The optimized case effectively makes the pressure gradient smooth from hub to shroud as the flow passes the passage. Figure 19: Isentropic efficiency vs. mass flow rate for original and optimized case. Figure 18: Pressure ratio vs. mass flow rate for original and optimized case.
###### Abstract  
Advances in information and communication technologies have made possible the emergence of new shopping channels. The so-called 'omnichannel' retailing mode allows customers to shop for products online and receive them at home. This paper focuses on the omnichannel delivery concept for the retailing industry, which addresses the replenishment of a set of retail stores and the direct shipment of the products to customers within an integrated vehicle routing formulation. Due to its _NP-Hardness_, a constructive heuristic, which is extended into a biased-randomized heuristic and which is embedded into a multi-start procedure, is introduced for solving the large-sized instances of the problem. Next, the problem is enriched by considering a more realistic scenario in which travel times are modeled as random variables. For dealing with the stochastic version of the problem, a simheuristic algorithm is proposed. A series of computational experiments contribute to illustrate how our simheuristic can provide reliable and low-cost solutions under uncertain conditions.  
omnichannel retail stores; vehicle routing problem; pick-up and delivery; biased-randomized heuristics; simheuristics +
Footnote †: journal:  
_Article_  
A Simheuristic Algorithm for Solving the Stochastic Omnichannel Vehicle Routing Problem with Pick-up and Delivery
# An Electromagnetic Circuit Design to Improve a Multi-Stage Coil-Gun's Energy Conversion Efficiency
## 2 The Coil Gun's Circuit Configuration and Projectile Selection  
A coil gun system consists of a solenoid coil that generates an electromagnetic force and a power supply that supplies current to the coil. High voltages and currents are usually applied/supplied using a charged capacitor. Typically, a high-voltage DC power supply, such as a booster converter, is required to charge the capacitor, and devices such as the SCR, IGBT, and FET are required to stably supply the stored electric charge. In this study, we used a DC power supply boosted up to 400 V using a booster converter boost circuit. Additionally, for the sake of circuit configuration convenience, we configured a coil gun circuit using an SCR thyristor device. Furthermore, in this study, we designed a multi-stage coil gun targeting a projectile velocity of 100 m/s with nine stages. We chose the projectile before designing and experimenting with any circuit. In the coil gun, a projectile accelerates by promptly receiving an electromagnetic force. Hence, it should be composed of a magnetic material. If its volume increases, the electromagnetic force required for acceleration increases. Therefore, upon deciding the projectile's shape, a coil gun circuit that will generate the appropriate electromagnetic force should be designed.  
Figure 1 shows an image of the projectile used in this experiment. The projectile was composed of a piece of S45 C steel with a 7.5 mm diameter and a length of 35 mm. Its weight was 11.35 g. Even though we chose steel, which is advantageous when it comes to its material availability and ease of fabrication, using a high-permeability metal, such as permalloy, can help increase the projectile's velocity.
## 2 Significance of Research  
Many existing structures use RC frames that fail to meet quality standards. In regions with moderate to low seismic activity, these frames are built without necessary seismic detailing, compromising safety and integrity. Such constructions are prevalent in industrial, residential, and commercial areas. The past performance of these poorly designed frames during seismic events has been inadequate, leading to concerns about their reliability [33; 34; 35; 36; 37; 38]. Thus, evaluating and improving these substandard buildings is crucial for mitigating risks and ensuring occupant safety.  
This research examines the potential for collapse among deficient RC structures and evaluates the effectiveness of all-steel Tube-in-Tube BRBs in mitigating such risks. This innovative solution not only enhances seismic performance but also remains cost-effective. In light of the substantial ground motion event recorded in Kahramanmaras in 2023, shake table experiments were conducted on two one-third-scale structural models: the first serves as a standard representation of a typical substandard RC building (reference frame), while the second features an advanced Tube-in-Tube system designed to improve structural integrity.  
The experimental outcomes were subsequently aligned with the analytical framework. This calibration facilitated a more precise depiction of the joint's seismic response, underscoring the significance of integrating both empirical and theoretical methodologies for evaluating the efficacy of structures engineered to withstand seismic activity. The findings from this comprehensive investigation are meticulously scrutinized and juxtaposed regarding essential global response indicators and the diverse damage manifestations recorded during the shake table assessments. This analysis seeks to elucidate the overall viability of the proposed alternative design strategy.
# An Analysis of Cloud Security Frameworks, Problems and Proposed Solutions
## 4 Cloud Security Challenges and Proposed Solutions
### Managed Security Threats  
#### 4.1.1.1.2.  
Criminals employ cloud computing to target victims and misappropriate cloud services. They conduct DDoS assaults, phishing, email spam, and Bitcoin mining. Breaching a user's cloud infrastructure can have serious ramifications for businesses. As a result, it is critical for businesses to monitor cloud access and apply risk mitigation measures. In the event of cloud service misuse, disaster recovery and data loss prevention techniques are critical to the recovery process. Cloud computing abuse can take various forms, including [38, 39]:  
Figure 6: Top Cloud Security threats.  
* Unauthorized Access
* Data Breaches
* Resource misuse
* Cryptocurrency mining
* Spamming and phishing  
**Solution**:  
Use rigorous authentication measures such as multi-factor authentication (MFA) to ensure that only authorized users may access cloud services. Review and adjust user access rights depending on their positions and responsibilities on a regular basis.  
Monitor and analyze user activities: Use security monitoring technologies to detect any unusual or suspicious activity in the cloud environment. Use log management and analysis software to track and investigate any suspected misuse or unauthorized access.  
Encrypt sensitive data: Encrypt data in transit and at rest using encryption methods. Encrypt critical data before storing it in the cloud, and make sure the cloud and users have safe communication routes.