System Parameters Research Articles

System Design and Parameter Optimization for Remote Coverage From NOMA-Based High-Altitude Platform Stations (HAPS)

System Design and Parameter Optimization for Remote Coverage From NOMA-Based High-Altitude Platform Stations (HAPS)

Impact of Sub-Chronic Exposure to Kalach on male reproductive system and sperm function: In Silico Modelling and In Vivo Study in Rats.

Impact of Sub-Chronic Exposure to Kalach on male reproductive system and sperm function: In Silico Modelling and In Vivo Study in Rats.

Elexacaftor/tezacaftor/ivacaftor and inflammation in children and adolescents with cystic fibrosis: a retrospective dual-center cohort study.

Cystic fibrosis (CF) is characterized by chronic neutrophilic inflammation in the airways. Elexacaftor/tezacaftor/ivacaftor (ETI) therapy has demonstrably improved clinical outcomes and quality of life in people with CF (pwCF), but its effects on systemic inflammatory parameters remain unclear. To evaluate the impact of ETI on systemic inflammation in children and adolescents with CF. Retrospective, dual-center observational, propensity score-matching study of pediatric pwCF on ETI. PwCF aged ⩽ 18 years treated with ETI at two Italian reference centers were included in this study. Data on immunoglobulins (Ig) (A, G, and M), γ-globulin, leukocyte levels, percent predicted forced expiratory volume in the first second (ppFEV1), sweat chloride (SC) concentration, and sputum cultures were collected at baseline, 12, and 24 months of treatment. Laboratory data of a control group (pwCF, not in ETI therapy, same demographic characteristics as the study group) were also collected. Sixty-six patients (30 males, median age: 12 years, F508del homozygous: 23) were included. Mean IgG levels (SD) significantly decreased (p = 0.001) from 1168.20 mg/dl (344.41) at baseline to 1093.05 mg/dl (258.73; 12 months) and 1092.87 mg/dl (232.42; 24 months). Similar reductions were observed for IgA and γ-globulin; IgM reduction was not statistically significant. Leukocyte levels also decreased significantly from 8.04 × 103/µl (3.23 × 103) at baseline to 6.61 × 103/µl (1.74 × 103) (12 months) and 6.45 × 103/µl (1.70 × 103; 24 months). As for the control group, no significant changes in the levels of Ig, leukocytes, and γ-globulin were detected throughout the study period (p > 0.05).The mean (SD) ppFEV1 and the overall mean (SD) SC concentration significantly decreased during the follow-up. Regarding cultures, 18 (27%) of the 27 patients positive (41%) for Staphylococcus aureus at baseline became negative during treatment. Three patients (4%) with persistently positive cultures for Pseudomonas aeruginosa during the first 12 months, became negative after 24 months. One patient (1.5%), with a baseline positive culture for Pseudomonas Aeruginosa, showed negative cultures after 12 months. ETI treatment improved respiratory outcomes and significantly reduced values of IgG, IgA, γ-globulin, and leukocytes, suggesting an effect on the systemic inflammatory response. Further research is warranted to elucidate the role of inflammatory parameters in monitoring response to therapy.

Calcium calmodulin kinase IV deficiency in podocytes prevents the development of lupus nephritis.

Calcium calmodulin kinase IV deficiency in podocytes prevents the development of lupus nephritis.

Accelerating lensed quasar discovery and modeling with physics-informed variational autoencoders

Strongly lensed quasars provide valuable insights into the rate of cosmic expansion, the distribution of dark matter in foreground deflectors, and the characteristics of quasar hosts. However, detecting them in astronomical images is difficult due to the prevalence of non-lensing objects. To address this challenge, we developed a generative deep learning model called VariLens, built upon a physics-informed variational autoencoder. This model seamlessly integrates three essential modules: image reconstruction, object classification, and lens modeling, offering a fast and comprehensive approach to strong lens analysis. VariLens is capable of rapidly determining both (1) the probability that an object is a lens system and (2) key parameters of a singular isothermal ellipsoid (SIE) mass model – including the Einstein radius (θE), lens center, and ellipticity – in just milliseconds using a single CPU. A direct comparison of VariLens estimates with traditional lens modeling for 20 known lensed quasars within the Subaru Hyper Suprime-Cam (HSC) footprint shows good agreement, with both results consistent within 2σ for systems with θE < 3″. To identify new lensed quasar candidates, we began with an initial sample of approximately 80 million sources, combining HSC data with multiwavelength information from Gaia, UKIRT, VISTA, WISE, eROSITA, and VLA. After applying a photometric preselection aimed at locating z > 1.5 sources, the number of candidates was reduced to 710 966. Subsequently, VariLens highlights 13 831 sources, each showing a high likelihood of being a lens. A visual assessment of these objects results in 42 promising candidates that await spectroscopic confirmation. These results underscore the potential of automated deep learning pipelines to efficiently detect and model strong lenses in large datasets, substantially reducing the need for manual inspection.

Fuzzy modelling and cost optimization of fault-tolerant system with service interruption.

Fuzzy modelling and cost optimization of fault-tolerant system with service interruption.

Dynamic Performances Analysis of an Electric Motorbike in case of Transient Excitation by Multi Body Dynamic Model

Abstract The dynamic performances of an electric motorbike subjected under transient road profile is analyzed by a Multi-Body Dynamics (MBD) 4 degrees of freedom (4DOF) model. The dynamic characteristics between suspension elements connected to the vehicle frame are determined by a MBD model. The electric motorbike specifications are selected based on the designed vehicle model, including size parameters and loading distributed in the front and rear axles of the vehicle. Suspension system parameters include the stiffness of the spring and the damping coefficient of the shock absorber, which is selected in the common value range of the vehicle’s suspension system, corresponding to the natural frequency and damping ratio. The transient road profile according to the IRC 99 - 1988 standard, has the length (d1 ) in range of 1.5÷3.7 (m), and examined velocity (v) range of 10÷80 (km/h). The evaluation indexes of the dynamic performances are analyzed including human body stability GAtr (%), safety working space of the suspension system GRtr (%) and the tire road holding ability GLtr (%). In which, the GAtr, GRtr, GLtr are respectively the ratios of the human vertical acceleration to the gravity acceleration, the dynamic suspension relative displacement to the suspension working deflection capacity, and the tire dynamic load to the tire static load. The obtained results show that with only one rider, the obtained GAtr was greater than 1 under excitation range of [d1 ≥ 2 (m), v>40 (km/h)], [d1 = 1.5 (m), v>13 (km/h)]. With two riders, d1 = 3.7 (m), the obtained GAtr was less than 1 in the entire examined velocity domain. Both front and rear suspension systems ensured GRftr <60% in all the investigated cases. In the front suspension system, with the same v and d1 , with two riders, the GRftr was always greater compared to the one rider case. The obtained GLtr was greater than the critical value of 1 with d1 = 3.7 m, v>36 (km/h). The lower d1 , the smaller critical velocity, causing the GLtr >1 is obtained. The obtained results show that the smaller the critical velocity or the critical stability condition of the designed vehicle decreases, when the applied loading or the excitation frequency increases.

Effects of the system parameters on the extreme low pressure of the draft tube during the successive load rejection using a systematic analysis framework

Effects of the system parameters on the extreme low pressure of the draft tube during the successive load rejection using a systematic analysis framework

Finite-time control of the discrete Sel’kov–Schnakenberg model: Synchronization and simulations

This study investigates the finite-time synchronization (FT-sync) of the Selkov–Schnakenberg reaction–diffusion system, utilizing Lyapunov functions and discrete finite-difference methods. Theoretical conditions are derived to achieve synchronization within a finite duration, a concept referred to as (FT-sync), which ensures rapid alignment of system states as opposed to classical asymptotic synchronization. The analysis is supported by numerical simulations that demonstrate the effectiveness of the proposed control strategies in enforcing synchronization under variable initial conditions and system configurations. In addition, the study investigates the impact of system parameters on spatiotemporal dynamics and synchronization patterns. These results hold significant value for practical applications requiring synchronization, such as in chemical reactors and biological systems, while also enriching the theoretical understanding of finite-time dynamics in reaction–diffusion systems.

Dynamical analysis and preassigned-time intermittent control of memristive chaotic system via T-S fuzzy method.

In this paper, we propose a novel fourth-order memristive chaotic system (MCS), in which both its dynamical behaviors and the preassigned-time stabilization problem are analyzed. First, the dynamical behaviors of the proposed MCS are studied in detail, such as the infinite unstable equilibrium points, the chaotic attractor, the Lyapunov exponents, the Kaplan-Yorke dimension, and the bifurcation. Then, the T-S fuzzy method is employed to characterize the MCS, and a simpler model is built to deal with the nonlinearity caused by the memristor in the MCS. In addition, two intermittent controllers are proposed to guarantee the preassigned-time stability and the settling time, which can be set freely, independent of system parameters and initial state. Finally, numerical simulations provide solid confirmation for the validity of these theoretical results.

Estimation of harmonic impedance and resonance in power systems

Since power systems are designed to work at the fundamental frequency, the presence of other frequencies from various sources may induce series and parallel resonances, leading to damage. The behavior of the power system in the presence of harmonics becomes evident with knowledge of harmonic impedance. Measurement offers the most accurate means of estimating harmonic impedance. However, when precise data of the power system parameters are available, highly satisfactory results can be achieved through calculation methods, particularly regarding loads, which are unknown and always change. This paper presents a study on estimating harmonic impedance using the Electromagnetic Transients Program Alternative Transient Program Draw (EMTP-ATPDraw) program, applied to an authentic network of Petrovice line 67, 22/0.4 kV, located in the Czech Republic. Hypothetically, the network was subjected to harmonic injection from a source (3rd, 5th, 7th, 9th, and 11th harmonics), and the harmonic impedance was calculated for three different variants: individual harmonics, all harmonics, and all except the 9th harmonic. The results show that the presence of the 9th harmonic can lead to a parallel resonance. This study is the first to employ EMTP-ATPDraw for programming this network. It gives the possibility to create a network database for different operating conditions, offering an asset for future project planning.

Ocean acidification and its regulating factors in the East China Sea off the Yangtze River estuary.

Ocean acidification and its regulating factors in the East China Sea off the Yangtze River estuary.

Implementation of Environmental Parameter Control System in Green House to Increase Vegetable Production

The use of green houses in plant cultivation is one way to approach optimal conditions for plant growth. Green houses are generally useful for protecting plants from extreme air temperatures. This requires further study of the smart features that will be built to support the concept of greenhouse agriculture. The development of automation technology is expected to help the monitoring system of parameters that affect the production of vegetable crops such as air temperature, and air humidity. These parameters will be monitored remotely using the Internet of Things (IoT) method. Based on the measurement results from the location at POLMED campus. For Medan Selayang the maximum temperature is 26.4oC and humidity is 68.8%. For the location in Medan Johor the maximum temperature is 25.4oC and humidity is 68.1%. For Medan Baru location, the maximum temperature is 25.1oC and humidity is 68.3%. For Medan Helvetia location, the maximum temperature was 24.7oC and humidity was 69%. Based on the test results, the temperature and humidity parameters can be monitored remotely by 106.4 km via the internet.

SEISMIC EVALUATION OF ADVANCED CONNECTION SYSTEMS IN WOOD-FRAMED SHEAR WALLS FOR STRUCTURAL DESIGN

Wood-framed shear walls are commonly used to construct low- to mid-rise buildings, particularly in seismic regions. However, as seismic demands increase, the need for more robust, efficient, and cost-effective connection systems is critical to improve the performance of these shear walls. This paper evaluates advanced connection systems for wood-framed shear walls in seismic applications, focusing on their effectiveness in enhancing lateral load resistance, reducing damage, and improving overall system performance. The study aims to provide valuable insights for designers, engineers, and builders to improve the seismic resilience of wood-framed buildings. seismic performance of wood-framed buildings, advanced connection systems, and structural wood design. Determine areas requiring further investigation. The fundamentals of displacement-based seismic design are presented along with a description of the system parameters required for its application. A simple numerical model capable of predicting the cyclic response and energy dissipation characteristics of wood shear walls under general quasi-static cyclic loading is presented to evaluate these parameters for wood-framed buildings. The generalization of this model to three-dimensional wood-framed structures is also discussed. As an application example, the displacement-based seismic design of a simple one-story shear wall building is presented. In turn, this design approach is validated by nonlinear dynamic time-history analyses using earthquake records representative of the hazard levels associated with the design performance levels.

Voltage profile enhancement of an AVR system using ant lion optimization algorithm

Abstract This paper addresses voltage regulation, which is a critical issue in power systems. The automatic voltage regulator (AVR) plays a crucial role in maintaining voltage regulation within permissible limits The AVR system's dynamic behaviour is improved by applying the Proportional (KP) Integral (KI) Derivative (KD) (PID) controller. The primary challenges of using a PID controller in AVR include difficulties in tuning parameters to handle nonlinearities, load disturbances, and system dynamics, leading to potential instability, overshoot, or slow response. The controller parameters are tuned with Ant Lion Optimisation (ALO) algorithm and Integral Time Absolute Error (ITAE) as an objective function. Also, the proposed system has the ability to improve the transient response of AVR by decreasing the maximum overshoot, settling time, rise time, and peak time magnitudes of the generator terminal voltage with eliminating the steady state error. Once the suggested method had produced the best values for the three gains i.e., KP, KI, and KD of the PID controller, a transient response analysis is examined and compared with some of the existing techniques such as Bat Algorithm (BA), Grey Wolf Optimisation (GWO) and Biogeography Based Optimisation (BBO) algorithm to highlight the novelty of the proposed ALO optimized PID controller. Transient response analysis, root locus analysis, and bode analysis are used to assess the AVR system's stability. Comparisons to three well-known optimization techniques corroborate the findings. The results show that this new suggested method performs exceptionally well even when there are significant variations in power system parameters and load uncertainties.

A Brief Comparison of Self-Weight Deflection and Optical Path Difference of Lens Mount for Space Applications

Optomechanical lenses can experience varying levels of stress, which can have a notable impact on optical parametric systems. To ensure proper alignment, positioning, and location of lens components within design tolerances, it is crucial to have a robust support structure in place for optical systems. The primary load on lens assemblies typically comes from their own weight in different gravity orientations. This study employs an analytical approach to examine the effects of stress resulting from lens mounting on the wave front passing through the lens, which can alter the optical path. Additionally, when an elastomer-mounted lens bears weight, the elastomer can bend, causing the lens to move and the optical axis to become de-centred. Through the use of these analytical methods, designers can identify potential issues with optical elements and mounting conditions, allowing them to take steps to minimize stress. The study's findings underscore the substantial differences in optical path and self-weight deflection between analytical and ideal methods.

Systemic Multi-Objective Optimization of Induction Motor-Driven Electromechanical Systems

The optimization of electromechanical systems, such as those involving induction motors and gearboxes, is crucial for improving energy efficiency, system performance, and reliability in industrial applications. This paper presents an advanced methodology for optimizing the energy efficiency of electromechanical systems, integrating both mechanical and electrical subsystems to minimize the system's overall weight, energy losses, and transient response time. The optimization problem is approached holistically, considering the interdependence of various system parameters and applying multi-objective optimization techniques to address conflicting objectives. The analysis focuses on optimizing the gearbox speed ratio to minimize the relative weight of the motor-gearbox system while maintaining operational efficiency. A systemic approach, utilizing convex surrogate modeling and multi-stage gearboxes, is proposed to improve the scalability of the solution. The results demonstrate the existence of optimal gearbox speed ratios for various motor sizes and configurations, offering insights into the best design choices for minimizing system weight and optimizing performance. These findings apply to a range of real-world systems, including electric vehicles and industrial machinery, where minimizing weight and optimizing energy efficiency are critical for improving overall system performance and reducing operational costs.

Nanofibers of PMMA/TiO2 Produced by Electrospinning

The method of electrospinning with a rotating cylinder collector was used to prepare PMM/TiO2 nanofibers. The effect of the collector rotation speed on the diameters, morphology, and structural properties of the prepared PMM/TiO2 nanofibers was studied, with the remaining parameters of the electrospinning system held constant. relied on the FE-SEM to study the diameters and regularity of the prepared nanofibers, which showed that the obtained nanofibers with diameters of 366 nm decreased to 127 nm and their regularity increased as the collector speed increased. The X-ray diffraction spectra showed that the prepared PMM/TiO2 nanofibers have an amorphous structure and begin to transform into a polycrystalline structure with increasing collector speed. Functional groups identified through FTIR tests have been shown to not be affected by the increase in rotation speed, regularity, or decrease in the diameter of the prepared PMM/TiO2 nanofibers.

Study on the dynamic load sharing characteristics of nutation face gear transmission

The nutation face gear transmission is a type of power splitting, and the effects of system parameters such as stiffness and transmission error on load distribution are not yet well understood. The Load Tooth Contact Analysis (LTCA) technique was used to calculate the time-varying meshing stiffness of the conjugate face gear pair. A 22-degree-of-freedom bending-torsional-axial coupled dynamic model of the system was established considering parameters such as support stiffness, time-varying meshing stiffness, meshing error, and installation error. A test bench for nutation face gear transmission system was set up, and experimental results shown that the dynamic model of the nutation face gear system had an accuracy of 2.32%. Based on the solution of the dynamic meshing force of the conjugate face gear pairs, the dynamic load sharing coefficient of the nutation face gear transmission system was defined. Through simulation calculations, the effects of support stiffness, comprehensive meshing error, and torsional stiffness of input shaft on the dynamic load characteristics of the system were analyzed. The research results indicate that the radial support stiffness of each face gear and the coupling stiffness between the oblique axis segment of the input shaft has the greatest impact on the load sharing coefficient. Reducing the radial support stiffness of the left branch, increasing the radial support stiffness of the right branch, and increasing the coupling stiffness between the oblique axis segment of the input shaft can improve the system's load-sharing performance by 76%. The asymmetry of the comprehensive meshing error parameters in the two power transmission branches can increase the system's load-sharing coefficient up to 1.8. These findings provide an important basis for the structural and stiffness parameter design of nutating face gear transmissions.

Probability Density Evolution and Fractional PID Control of Magnetic Bearing-Rigid Rotor System Influenced by Multisource Stochastic Factors

Magnetic bearings are widely used in engineering for their remarkable advantages of low friction, no wear and high speed. In this paper, the dynamics and control of the magnetic bearing-rigid rotor system under the influence of multisource stochastic factors are studied. Firstly, a model of magnetic bearing-rigid rotor system driven by multiplicative noise and additive noise is established. Secondly, the stationary response probability density function (PDF) of the proposed magnetic bearing system is obtained by using the amplitude envelope stochastic average method. Then we analyze the influence of different system parameters and noise intensity on the magnetic bearing-rigid rotor system, and find that internal stochastic factors are the main factors affecting the stability of the bearing system. Finally, the fractional Proportional Integral Derivative (PID) control of the system is studied. Based on the numerical analysis, we verify the effectiveness of the control strategy and draw the conclusion that adjusting appropriately the parameters of fractional PID controller can make the magnetic bearing system control better.