System Parameters Research Articles

Research on Optimization of Water Jet Coupling System Parameters in Automated Ultrasonic Phased Array Inspection

When ultrasonic testing is used for non-destructive testing of welded workpieces, the surface of the ultrasonic transducer or wedge should have a good coupling effect with the measured surface of the workpiece. However, in actual ultrasonic testing, it is difficult to ensure that the ultrasonic transducer completes uniform scanning, resulting in poor coupling between the probe and the workpiece, resulting in low acoustic coupling stability of ultrasonic testing. In view of the above problems, this paper designs and constructs an automated ultrasonic phased array inspection platform using water jet coupling. By taking water flow rate, coupling distance, and transducer center frequency as independent variable parameters of the water jet coupling system, and using the received sound wave amplitude as the response variable for experimental comparison, a response surface analysis is conducted on these parameters to optimize the detection resolution of the automated ultrasonic inspection system. The results show that the most accurate system detection results are achieved when the water flow rate is 0.4 L/min, the coupling distance is between 1.0-1.6 mm, and the transducer center frequency is 10 MHz. This effectively solves the problem of low stability in ultrasound detection coupling, improves the detection efficiency, and provides guidance for further research on the imaging effect of automated ultrasonic phased array inspection in subsequent studies.

Speed synchronization of two DC motors with independent loads based on the higher load torque

Dual-motor and multi-motor electric drive systems have been used in many industrial applications, and speed synchronization of the motors can always get worse by system parameter uncertainties and load torque perturbations. This work focuses on the application of adjustable speed double-direct current (DC) motor drive control systems. In this paper, a system of two DC motors with armature control at different load conditions has been built. The synchronization of these motors was set basing on the higher torque of the two motor shafts. When two DC motors operate at different shafts a challenge appears in synchronization of their speeds, particularly with the existence of load difference allocated on their shafts. This work paid special attention to this problem. It presents a dynamic simulation of speed control and synchronization of dual DC motor drive. The results show the advantages of the used technique in terms of steady-state and transient performance.

High-precision two- and three- dimensional atom localization in a microwave and radio-frequency driven Δ∇ system

We introduce a new approach for precise and high-resolution two-dimensional (2D) and three-dimensional (3D) atom localization in a four-level Δ∇ atomic system driven by microwave (M) and radio frequency (R) fields. In the proposed work, additional microwave and radio-frequency fields are utilized for an efficient control of the localization precision. Due to the spatially varying atom-field interaction, the probe susceptibility become position dependent and therefore, one can directly ascertain the position probability distribution of an atom by analyzing the probe spectra. The phase-sensitive property of the atomic system plays a significant role in substantially reducing the uncertainty associated with atom position measurements. We have studied the system behavior through the analysis of dressed states, which forms the basis for its physical interpretation. The increase in precision for measuring the atom’s position is a result of interference between one-photon excitation and the phase-dependent three-photon excitation arising from the closed interacting contour within the laser-driven atomic system, as demonstrated through both numerical calculations and qualitative analyses. The findings indicate that precise sub-wavelength atom localization can be attained by appropriately adjusting the system parameters. Also, the optimal adjustment of these parameters can lead to 100% probability of locating the atom at a particular position within 2D and 3D subspaces.

Adaptive Iterative Learning Constrained Control for Linear Motor-Driven Gantry Stage with Fault-Tolerant Non-Repetitive Trajectory Tracking

This article introduces an adaptive fault-tolerant control method for non-repetitive trajectory tracking of linear motor-driven gantry platforms under state constraints. It provides a comprehensive solution to real-world issues involving state constraints and actuator failures in gantry platforms, alleviating the challenges associated with precise modeling. Through the integration of iterative learning and backstepping cooperative design, this method achieves system stability without requiring a priori knowledge of system dynamic models or parameters. Leveraging a barrier composite energy function, the proposed controller can effectively regulate the stability of the controlled system, even when operating under state constraints. Instability issues caused by actuator failures are properly addressed, thereby enhancing controller robustness. The design of a trajectory correction function further extends applicability. Experimental validation on a linear motor-driven gantry platform serves as empirical evidence of the effectiveness of the proposed method.

Whole Body Control of Mobile Manipulators With Series Elastic Actuators for Cart Pushing Tasks.

Human-centered environments provide affordance for the use of two-handed mobile manipulators. Yet robots designed to function in and physically interact with such environments are not yet capable of meeting human users' requirements. This work proposes a whole body control framework of a two-handed mobile manipulator driven by series elastic actuators (SEAs) for cart pushing tasks. A whole body dynamic model for an integrated mobile platform and on-board arms is revealed, which takes into account the interaction forces with the cart. Then, the explicit force/position control of the mobile manipulator is performed. It enables the robot to interact dynamically with the environment while providing motion, i.e., the manipulators provide both output force control and motion control for pushing a cart. To cope with the highly nonlinear system dynamics and parameter variation of a SEA-driven mobile manipulator, this work proposes an adaptive robust controller based on a novel integral barrier Lyapunov function for cart pushing tasks by considering model uncertainty. The proposed controller enables the mobile manipulator to complete cart pushing tasks by regulating the position and output force of the mobile base and arms. The experimental results show the effectiveness of this approach in cart pushing tasks.

The Construction of Learning Support Parameters for Adults with Autism

ABSTRACT Existing literature suggests adults with autism may only have limited access to support, which may fail to meet their diversified learning needs. This study thus aims to propose dimensions and parameters of a learning support system for adults with autism by means of focus group interviews (N = 30). The content analysis of interview data produced a four-dimensional learning support system for adults with autism: supporters, learners, learning resources, and learning environments. The supporter dimension was composed of four parameters, namely government support, social support, teacher support, and parental support. The learner dimension had two parameters, including satisfying interests and improving ability. The learning resources dimension comprised two parameters, involving learning aids and curriculum support. The learning environment dimension included two parameters, containing physical environment support and social-emotional environment support. The learning support system could be used as a benchmark for the development of adults with autism spectrum disorder. With parameters of learning support for adults with autism, this study is expected to provide guidance and reference for work and related research on learning support for adults with autism, so that their learning needs can be addressed and employment can be improved.

Enhancing Road Safety Vehicle Black Box with Advanced Accident Detection and Alert System

Autonomous vehicles want reliable and strong sensor suites and alert systems. This paper discusses the composition and performance of a sophisticated monitoring and alert system for automobile vehicle parameters. The number of automobiles has also grown quickly to meet the enormous population. Additionally, this resulted in an increase in accidents. The accident prevention strategies now in use are all static and dated. Additionally, there is no reliable accident detection system. Automobile vehicle parameters are continuously monitored by a microcontroller which stores the data logs containing vehicle parameter data into a sheltered digital memory card and in the cloud storage. The system doesn't solely record the vehicle parameters data of the automobile periodically, but also actively monitors for any sudden vehicle accident detection. The sensor may facilitate folks to analyze the accident quickly and lawfully when a collision happens to alert the emergency services to that location. The system will update the information whenever an abnormal system event happens. A black box in a vehicle gather driving information about the vehicle before, during and after a crash

Combination of fuzzy control and reinforcement learning for wind turbine pitch control

Abstract The generation of the pitch control signal in a wind turbine (WT) is not straightforward due to the nonlinear dynamics of the system and the coupling of its internal variables; in addition, they are subjected to the uncertainty that comes from the random nature of the wind. Fuzzy logic has proved useful in applications with changing system parameters or where uncertainty is relevant as in this one, but the tuning of the fuzzy logic controller (FLC) parameters is neither straightforward nor an easy task. On the other hand, reinforcement learning (RL) allows systems to automatically learn, and this capability can be exploited to tune the FLC. In this work, a WT pitch control architecture that uses RL to tune the membership functions and scale the output of a fuzzy controller is proposed. The RL strategy calculates the fuzzy controller gains in order to reduce the output power error of the WT according to the wind speed. Different reward mechanisms based on the output power error have been considered. Simulation results with different wind profiles show that this architecture performs better (123.7 W) in terms of power errors than an FLC without RL (133.2 W) or a simpler PID (208.8 W). Even more, it provides a smooth response and outperforms other hybrid controllers such as RL-PID and radial basis function neural network control.

A Modified Perturbation Method for Global Dynamic analysis of Generalized Mixed Rayleigh–Liénard Oscillator with Cubic and Quintic Nonlinearities

Abstract Deriving analytical relationship between the system parameters and amplitude of the limit cycle is a meaningful and challenging task. Currently, numerous existing analytical approximate methods struggle to achieve this goal when expressions of restoring force or nonlinear damping is complicated. To overcome this shortcoming, this study proposes a modified generalized harmonic function perturbation method. Using the proposed method, a generalized mixed Rayleigh–Liénard oscillator with cubic and quintic nonlinearities was investigated. The analytical relationships between the system parameters and amplitude of the limit cycle, as well as the expression of its characteristic quantity, were derived. By employing these analytical relationships, the existence, stability, number, position, and amplitude of each limit cycle are quantitatively analysed. The homoclinic and heteroclinic bifurcations were also predicted using the above analytical relationships. Additionally, analytical approximate solutions for this oscillator were calculated using the proposed method. All results obtained in this study were subsequently confirmed numerically to demonstrate their feasibility and validity. Consequently, the proposed method can be considered an effective supplement to perturbation-based methods. This also implies that the work presented in this paper has a certain theoretical significance and application value in the research area of quantitative analysis methods for strongly nonlinear oscillators.

Stochastic response and stability analysis of nonlinear vehicle energy-regenerative suspension system with time delay

With the rapid development of new energy vehicles, a novel vehicle energy-regenerative suspension for simultaneous vibration suppression and energy harvesting has become one of the key development directions of the next generation of vehicle design. In order to improve the performance of suspension system, the time-delayed feedback control is applied to the novel suspension system subjected to different external excitation. At the same time, there are few studies related to the stochastic dynamics of nonlinear vehicle energy-regenerative suspension system with time delay. This paper studies stochastic response and stability of nonlinear vehicle energy-regenerative suspension with time-delayed feedback control under the excitation of Gaussian white noise. First of all, a stochastic dynamic model of the nonlinear vehicle energy-regenerative suspension with time delay system is established. Secondly, using the stochastic averaging method based on generalized harmonic function, the steady-state probability density function (PDF) of amplitude is obtained. The accuracy of the presented approach is verified through the comparison of analytical and numerical solutions. In addition, through combining the stochastic averaging method with the Khasminskii method, the top Lyapunov exponent (TLE) of the system is obtained, and then the influence of time delay and system parameters on the asymptotic Lyapunov stability is discussed. Finally, the effects of time delay and system parameters on system performance are also studied.

A Study toward the Model Independence of Various Heating Rates Method in Thermoluminescence Glow Curve Analysis

This study analyzes thermoluminescence (TL) glow curves simulated in general order kinetics (GOK), one trap one recombination center (OTOR), and non‐interactive multi‐trap system (NMTS) models using various heating rates (VHR) method in linear heating scheme to extract the activation energy. A theoretical analysis to determine activation energy from TL curves using OTOR and NMTS models in an iterative manner, where the TL intensity is determined by using the Lambert‐W function, is proposed with its limitations. It is established that the activation energies in OTOR and NMTS models consist of the relevant GOK term and a respective correction term. Systematic analysis is carried out to study the improvement of the accuracy of activation energy derived from OTOR and NMTS model TL curves over the GOK model calculation. A quantitative analysis of the quasi‐equilibrium (QE) approximations is carried out for choosing appropriate system parameters. The validity of QE conditions are determined by studying variations of full width at half maximum as well as area under the curve as a function of heating rate. The present method is applied on some experimental data to estimate activation energies. This investigation reveals that the activation energy derived in VHR method has negligible dependence on the underlying theoretical models, i.e., the activation energy derived from GOK model calculation is significantly accurate for experimental scenario.

Engineering dynamical photon blockade with Liouville exceptional points

We investigate the dynamical blockade in a nonlinear cavity and demonstrate the connection between the correlation function g(2)(t) and system parameters in the entire nonlinear region. Utilizing the Liouville exceptional points (LEP s ) and quantum dynamics, a near-perfect single-photon blockade (1PB) can be achieved. By fine-tuning system parameters to approach the second-order LEP (LEP2), we improved single-photon statistics in both weak and strong nonlinearity regimes, including a significant reduction of g(2)(t) and a pronounced increase in the single-photon occupation number. In the strong nonlinearity region, the maximum photon population may correspond to stronger antibunching effect. Simultaneously, the time window and period of blockade can be controlled by selecting detuning based on the LEP2. Furthermore, the 1PB exhibits robustness against parameter fluctuations, and this feature can be generalized to systems for implementing single-photon sources with nonharmonic energy levels.

Choosing a camera and optimizing system parameters for speckle contrast optical spectroscopy

Speckle contrast optical spectroscopy (SCOS) is an emerging camera-based technique that can measure human cerebral blood flow (CBF) with high signal-to-noise ratio (SNR). At low photon flux levels typically encountered in human CBF measurements, camera noise and nonidealities could significantly impact SCOS measurement SNR and accuracy. Thus, a guide for characterizing, selecting, and optimizing a camera for SCOS measurements is crucial for the development of next-generation optical devices for monitoring human CBF and brain function. Here, we provide such a guide and illustrate it by evaluating three commercially available complementary metal–oxide–semiconductor cameras, considering a variety of factors including linearity, read noise, and quantization distortion. We show that some cameras that are well-suited for general intensity imaging could be challenged in accurately quantifying spatial contrast for SCOS. We then determine the optimal operating parameters for the preferred camera among the three and demonstrate measurement of human CBF with this selected low-cost camera. This work establishes a guideline for characterizing and selecting cameras as well as for determining optimal parameters for SCOS systems.

Pulsed-field vs. cryo-balloon based pulmonary vein isolation: does reduced autonomic modulation effect freedom of atrial fibrillation?

Abstract Background Pulsed-field ablation (PFA) is a new energy source integrated into single-shot devices enabling pulmonary vein isolation (PVI) during atrial fibrillation (AF) ablation. It has been demonstrated that PFA is noninferior to conventional thermal ablation. Conceptually, PFA preferentially damages cardiomyocytes and our prior data show that PFA causes less damage to neuronal tissue and reduced autonomic dysfunction than CBA. Here, we analyzed heart rate variability (HRV) as an additional parameter of intracardiac nervous system and whether the damage to neuronal tissue quantified by biomarker release and functional parameters might influence the recurrence rate of atrial fibrillation in PFA and CBA treated patients. Methods We prospectively included consecutive patients with paroxysmal AF undergoing index PVI applying PFA (n=65) or CBA (n=112). We quantified the ablation-dependent effect on intracardiac autonomic nervous system by comparing resting heart rate (HR), HRV and circulating concentrations of the neuronal biomarker S100B. Recurrent AF was detected using Holter ECGs, wearables and telephone interviews. Results Baseline characteristics did not differ between PFA and CBA (age 66 vs. 68 years, female 33% vs. 39%, CHADS-VASc Score 2.1 vs. 2.2, indexed LA volume 32 vs. 31 ml/m², BMI 27.3 vs. 27.4 kg/m²). After CBA-based PVI, HR increased (pre 63 vs. post 70 bpm, p<0.001) and HRV decreased (SDNN pre 54 vs. post 26 ms, p=0.007). After PFA-based PVI, HR and HRV remained stable (HR pre 63 vs. 64 bpm, p=0.591; HRV SDNN pre 37 vs. post 36 ms, p=0.890). In a direct comparison, the HR-increase and HRV-decrease observed after CBA-based PVI was significant compared to PFA (0.8 vs. 7.3 bpm, p<0.001 and SDNN -1 vs. 29 ms, p=0.003). We reported previously that PFA induced less S100B release (28 ng/dl) than CBA (68 ng/dl, p<0.001) and that PV reconnection rates in ReDo procedure were similar between PFA (40%) and CBA (40%). 1 year follow-up revealed freedom of AF in 79% after PFA and 73% after CBA (p=0.230). Dividing patients in upper and lower half of HR increase and S100B release after PVI, patients showed no difference in recurrence rates after CBA. Conclusion These data suggest that neurocardiac damage near the pulmonary veins seems not to contribute to freedom of AF recurrences after PVI.

A Review of Relationship between the Metallogenic System of Metallic Mineral Deposits and Lithospheric Electrical Structure: Insight from Magnetotelluric Imaging

In development over 70 years, magnetotelluric (MT) sounding, a high-resolution technique for subsurface electrical resistivity imaging, has been widely applied in resource exploration in the Earth. The key factors of the metallogenic system of metallic mineral deposits can be closely correlated to the electrical anomalies of the lithosphere. In this paper, we review the relationship between the electrical resistivity model of the lithosphere and the metallogenic system. At the beginning, we indicate why the electrical parameters relate to the metallogenic system in all geophysical parameters. The advantage of MT sounding in sketching an electrical resistivity model of the lithosphere is subsequently discussed, and some methods of data processing, analysis and inversion are also introduced. Furthermore, we summarize how to bridge the relationship between the electrical resistivity model of the lithosphere and metallogenic system, and analyze the influence of the rheological variation estimated from conductivity in the lithosphere on mineralization. In the end, we list some typical cases of the application of MT sounding in mineral exploration, and also give some suggestions for future work. This study is aimed at providing guidance in discussing the metallogenic system using an electrical resistivity model.

Study on the Morphological Analysis and Evolution of the Street Network in the Historic Urban Area of Changsha City from 1872–2023

This study focuses on the streets and spatial networks of the historic urban area in Changsha, the capital of Hunan Province, China, by mainly investigating the evolution of their geometric and topological characteristics. It draws on the theories and methods of urban morphology and space syntax, combines the digital historical maps at different times, and uses methods such as historical map spatial interpretation, geographic information system (GIS), sDNA tools, and urban morphological parameter analysis to explore and sort out the evolutionary process of the street and alley network in Changsha from the early modern period to the present. The paper constructs a parameter system for analyzing the street and alley network of historic urban areas from a geometric and topological perspective. It introduces the indicators of road density, road orientation, intersection density, and approaches such as closeness, betweenness, and intelligibility in space syntax into the parameter analysis framework of street and alley network morphology and spatial characteristics evolution. By comparing the changes in various parameters at different spatial scales, the process of the spatial order evolution of the street and alley network in the historic urban area is analyzed, and the evolutionary rules of the various periods’ morphological characteristics are extracted.

#1972 Changes in vegetative hemodynamic relationship in the comorbid state of patients with respiratory pathology

Abstract Background and Aims The parameters of the vegetative nervous system (VNS) and its relationship with the function of the central and renal vessels in patients with bronchial asthma (BA) in comorbidity with glomerular filtration dysfunction of the kidneys were studied and the above-mentioned indicators of complex treatment regimens were determined. Since the tension of neuropsychiatric predictors negatively affects the state of hemodynamics and internal organs directly of the VNS. The constant hyperactivity of this system due to chronic inflammatory processes is the starting point of vegetative imbalance. Method 68 patients with comorbidity with glomerular filtration dysfunction of the kidneys and 30 healthy individuals were examined. Studies were conducted in 36 patients with BA grade II-III (group 1, in which the level of glomerular filtration rate of the kidneys was determined by eGFRCKD-EPI ≥6 ml/min/1.73 m2) and 32 patients with BA grade IV (group 2, they were determined by eGFRCKD-EPI ≥60 ml/min/1,73m2). The functional state of the peripheral VNS was studied by cardiointervalography (CIG) using methods of mathematical analysis of indicators: Mode (Mo, sec.) and mode amplitude (AMo, %); Vasodilation of dependent endothelium (VDE) was determined by hyperreactive brachial artery Dopplerography test: maximum systolic velocity (Vmax) and vascular resistance index (IR). Results On the first day of admission to the hospital, patients were examined by the VNS meth, where eitonia and vagotonia were detected in practically healthy people, and hypersympathicotonia was determined in patients with BA with disorders of central and renal hemodynamics. A significant decrease in Mo parameters and an increase in AMo levels were analyzed when compared with the reference parameters of healthy individuals. This reflects the tension of the sympathetic department, and parasympathicotonia, on the contrary, decreased. There is a decrease in the ability of PA vessels to actively vasodilate due to an imbalance in the tone of the VNS. In the results of the hyperemic test, it was analyzed that in patients with BA in comorbidity with glomerular filtration dysfunction of the kidneys, the Vmax of blood flow decreases, and IR increases in parallel with the severity of the disease. All patients underwent complex therapy with halotherapy for 20 minutes daily and resonance therapy for the area of both kidneys for 5 minutes of exposure, once a day, for 10 days. After the course of treatment, there was a positive dynamics in the functional parameters of the state of the VNS. The indicators of CIG were analyzed, where hypaticotonia decreased by 6.7%, and the parameters of the parasympathetic system improved to 5.3%. Conclusion At the heart of the elevation of maladaptive processes of chronic respiratory inflammation, hypoxia of brain structures and dysfunctions of glomerular filtration of the kidneys, vegetovisceral imbalance develops. The regimens of complex therapy have a positive effect, both anti-inflammatory at the visceral level and a calming effect on the VNS.

The TESS-Keck Survey. XX. 15 New TESS Planets and a Uniform RV Analysis of All Survey Targets

The Transiting Exoplanet Survey Satellite (TESS) has discovered hundreds of new worlds, with TESS planet candidates now outnumbering the total number of confirmed planets from Kepler. Owing to differences in survey design, TESS continues to provide planets that are better suited for subsequent follow-up studies, including mass measurement through radial velocity (RV) observations, compared to Kepler targets. In this work, we present the TESS-Keck Survey’s (TKS) Mass Catalog: a uniform analysis of all TKS RV survey data that has resulted in mass constraints for 126 planets and candidate signals. This includes 58 mass measurements that have reached ≥5σ precision. We confirm or validate 32 new planets from the TESS mission either by significant mass measurement (15) or statistical validation (17), and we find no evidence of likely false positives among our entire sample. This work also serves as a data release for all previously unpublished TKS survey data, including 9,204 RV measurements and associated activity indicators over our three-year survey. We took the opportunity to assess the performance of our survey and found that we achieved many of our goals, including measuring the mass of 38 small (<4 R ⊕) planets, nearly achieving the TESS mission’s basic science requirement. In addition, we evaluated the performance of the Automated Planet Finder as survey support and observed meaningful constraints on system parameters, due to its more uniform phase coverage. Finally, we compared our measured masses to those predicted by commonly used mass–radius relations and investigated evidence of systematic bias.

Dynamics around small irregularly shaped objects modeled as a mass dipole

In this work, we investigate the dynamics of a spacecraft near two primary bodies. The massive body is considered to have a spherical shape, while the less massive one is elongated and modeled as a dipole. The dipole consists of two connected masses, one is spherical and the other is an oblate spheroid. The gravitational potential of the elongated body is determined by four independent parameters. To study the dynamics, we construct the equations of motion of a spacecraft with negligible mass under the effect of the current force model. The existence and locations of the equilibrium points are analyzed for various values of the system parameters. We found that the existence and locations of the points are affected by the system parameters. Also, we studied the linear stability of the equilibrium points. We found some stable collinear points when the oblateness parameter is negative, otherwise the points are not stable. We used the curves of zero velocity to identify the regions of allowed motion. Furthermore, we discussed the 2001 SN263 asteroid system and found some stable collinear points when the oblateness parameter is negative. In addition, the triangular points of the system are stable in a linear sense.

Stick–Slip Suppression in Drill String Systems Using a Novel Adaptive Sliding Mode Control Approach

A novel control technique is presented in this paper, which is based on a first-order adaptive sliding mode that ensures convergence in a finite time without any prior information on the upper limits of the parametric uncertainties and/or external disturbances. Based on an exponent reaching law, this controller uses two dynamically adaptive control gains. Once the sliding mode is reached, the dynamic gains decrease in order to loosen the system’s constraints, which guarantees minimal control effort. The proof of convergence was demonstrated according to Lyapunov’s criterion. The proposed algorithm was applied to a drill string system to evaluate its performance because such systems present variable operating conditions caused by, for example, the type of rock. The effectiveness of the proposed controller was evaluated by conducting a comparative study that involved comparing it against a commonly used sliding mode controller, as well as other recent adaptive sliding mode control techniques. The different mathematical performance measures included energy consumption. The proposed algorithm had the best performance measures with the lowest energy consumption and it was able to significantly improve the functioning of the drill string system. The results indicated that the proposed controller had 20% less chattering than the classic SM controller. Finally, the proposed controller was the most robust to uncertainties in system parameters and external disturbances, thus demonstrating the auto-adjustable features of the controller.