Nonlinear Analysis Approach Research Articles

Assessing Whether Negative Parenting Cognitions Bias Parent Report of Preschoolers' Externalizing Symptoms: A Regularized Moderated Non-Linear Factor Analysis Approach.

Parent report is frequently used to assess children's psychopathology, however, researchers have expressed concerns about the validity of parent reports. Some parental characteristics, attitudes, or beliefs may systematically bias a parent's report of their child's behaviors and functioning. Informed by social information processing models of parenting risk, parents with more difficulties reflecting on and interpreting their children's behavior may be at risk for less accurate reports. The present study conducted two regularized moderated non-linear factor analyses with LONGSCAN data to examine how parents' self-reported negative parenting cognitions were associated with structural parameters of parent-reported child aggression and attention problems. While differential item functioning (DIF) was present on the aggression and attention problems subscales as a function of negative parenting cognitions, the DIF was small in magnitude, inconsistent in directionality and did not significantly alter factor-level parameters. Negative parenting cognitions did demonstrate a small but significant negative impact on all latent externalizing factors (aggression and attention problems), such that caregivers with fewer negative parenting cognitions endorsed fewer items, and this was associated with a lower mean of each latent variable. Given that accounting for DIF did not contribute to meaningful differences in impact parameters or improve criterion validity, findings suggest that the aggression and attention subscales are functionally invariant to negative parenting cognitions, suggesting that externalizing symptoms can be reliability compared across parents of varying parenting cognitions.

A SGM-IHB approach for nonlinear free and forced vibration analysis of FG-GPLRC beams rested on viscoelastic foundation

A SGM-IHB approach for nonlinear free and forced vibration analysis of FG-GPLRC beams rested on viscoelastic foundation

Stability of steady-state solutions of Jeffcott rotor with varying rotational speed

AbstractThe behavior of flexible rotating systems with varying rotational speeds is essential in engineering applications. Analysis methods that consider linear dynamic models and many existing nonlinear analysis approaches assume constant rotational speed. These approaches are unsuited to study the dynamic interaction between driving torque and whirling motion in this class of applications. In this paper, an analysis of the stability and control of a Jeffcott rotor under varying operational conditions is presented. A nonlinear dynamic model of the system is formulated to enable a detailed stability and parametric analysis. A proportional-integral (PI) torque command is employed to achieve a steady-state rotational speed. Assuming constant lateral control effort, system equilibrium points and their stability characteristics as functions of the system’s parameters are analyzed. A control law that minimizes the lateral effort is derived. A feedback proportional lateral control strategy is introduced to enhance the system’s region of stability, particularly in the supercritical speed range. Finally, a simulation study is conducted to validate the analytical findings. Simulation results demonstrate the effectiveness of the proposed approach for defining stable operating conditions and improving system performance.

A Nonlinear Analytical Approach to Social Dynamics: Modeling the Impact of Moderate Da’wah on Promoting Tolerance and Social Cohesion in Indonesia

This study applies a nonlinear analytical approach to examine the role of Daiyah Fatayat (DIFA) in promoting tolerance and moderate da’wah in Indonesia. The research focuses on modeling the social dynamics that emerge from the interactions between da’wah messages and community responses, using a mathematical framework inspired by nonlinear systems theory. The rising threat of radicalization, which jeopardizes interfaith harmony, serves as the impetus for this study. By incorporating nonlinear modeling techniques, this research analyzes the application of key Qur’anic verses such as Q.S. Al-Baqarah: 221 and Q.S. Ali Imran: 104 within DIFA’s cadre training. The model captures how these verses influence tolerance and social cohesion over time. The study employs a combination of qualitative case study methods, including interviews, observations, and document analysis, and integrates these findings into a computational model. Results suggest that DIFA’s use of moderate da’wah can act as a stabilizing force within communities, fostering increased social harmony. This study highlights the potential for applied nonlinear analysis to provide insights into complex social phenomena such as radicalization and the promotion of tolerance.

A heterogeneous continuum traffic flow model considering mixed connected and autonomous vehicles

Under the background of mixed scenarios of Connected and Autonomous Vehicles and Connected and Autonomous Electric Vehicles, a novel mixed car-following model considering the information of multiple vehicles and the difference of safety spacing in different driving scenarios is proposed. Then, the corresponding heterogeneous continuum traffic flow model is derived. Secondly, through the linear and nonlinear analysis approaches, the linear stability condition and the KdV-Burgers equation are yielded to describe the characteristics of traffic flow evolution. Finally, numerical simulations are performed to explore the density evolution of traffic flow under different initial density and permeability conditions. The conclusions can be summarized as follows: (1) The derived model can well simulate spatiotemporal phase changes and traffic flow phenomena such as stop-and-go waves and local cluster effects. (2) With the increase of the permeability of electric vehicles and speed difference sensitivity coefficient, the road density decreases from 0.15veh/m to 0.06veh/m, the traffic congestion area decreases, and the traffic congestion is effectively suppressed, which also verifies the rationality of the above theory.

Continuum approach of nonlinear dynamic analysis of a rotating wind turbine blade considering hub motion

This paper reports the nonlinear dynamics of a large wind turbine blade considering the hub motion. The investigation is based on a continuum mathematical model, which is derived using the extended Hamilton principle. The proposed model is validated via comparison with both published results and numerical simulations obtained from open source software. The steady state amplitude curves as well as the dominating frequencies of the modal forces are compared and analyzed with discussions on the effects of the hub motion amplitude, yaw angle and rotational frequency of the blade. Comparison of dominant frequencies of modal forces shows that the skewed inflow can strengthen the periodic excitation whose frequency equals to the rotating frequency of the blade. The steady state amplitude curves show that vibration of the edge-wise mode is more significant than that of the flap-wise mode when under the hub motion excitation. Moreover, internal resonance between the first three modes is also observed. The skewed inflow has a significant effect on the first mode in terms of vibration amplitude and the most unfavorable direction of hub motion. Finally, recommendation on how to avoid the resonance and internal resonance of the blades under skewed inflow are given.

A simplified homogeneous approach for non-linear analysis of masonry infill panels under in-plane loads

This paper aims to create a unified model that effectively combines continuous 2-dimensional elements and discrete components to capture the nonlinear characteristics and failure mechanisms of solid and perforated masonry infill panels. Given that masonry infill behavior is primarily influenced by shear deformations, an equivalent model is developed by using multiple small square panels arranged diagonally and interconnected by two-component springs, encompassing axial and shear behavior at their intersections. For the sake of simplicity, the divided panels are assumed to behave elastically, with plasticity concentrated only in the axial component of the connector springs. Plastic behavior in the boundary elements was considered to involve both flexural and shear plastic hinges to provide an accurate estimation of the entire infill panel's behavior. To validate this approach, the simplified model is benchmarked against eight experimental masonry infill panels surrounded by steel or reinforced concrete frames and with or without openings. The results including global behavior and crack pattern were compared with available numerical predictions based on finite element method from the literature in addition to experimental outcomes. Ultimately, this comparison demonstrated that the homogeneous model could effectively predict the non-linear lateral behavior of the panels and accurately forecast crack patterns. Additionally, the use of unidirectional non-linear springs and the appropriate arrangement of elastic panels significantly reduced both pre-processing and analysis time.

Nonlinear Analysis and Topological Approaches towards a Deep Intelligent Framework for Privacy Assurance of Autonomous IoT Systems

The proliferation of autonomous Internet of Things (IoT) systems powered by deep learning and artificial intelligence has ushered in a new era of data-driven convenience and automation. However, this innovation comes hand in hand with heightened concerns regarding data privacy. This paper presents a comprehensive framework for Privacy Assurance in Autonomous IoT Systems (PAIS), which amalgamates cutting-edge technologies and best practices to safeguard individual privacy in the era of pervasive connectivity and autonomous decision-making. The PAIS framework comprises multifaceted strategies to address privacy challenges in autonomous IoT ecosystems. It leverages advanced encryption techniques, robust access control mechanisms, and anonymization protocols to ensure data confidentiality. Moreover, differential privacy mechanisms are deployed to protect the identities of individuals within data streams. An innovative aspect of PAIS is the integration of AI-driven privacy monitoring, which constantly evaluates data for potential breaches and triggers immediate responses when anomalies are detected. Ensuring regulatory compliance is a paramount facet of the PAIS framework, as it aligns with evolving data protection regulations globally. Users are afforded control and transparency through intuitive interfaces, enabling them to manage their data usage preferences effectively. The ethical implications of AI in privacy preservation are also examined within the framework, emphasizing the importance of fairness and bias mitigation. PAIS promotes a privacy-by-design approach, where privacy considerations are integral to the inception and development of IoT systems. Regular risk assessments are performed to identify potential privacy vulnerabilities, ensuring that the framework adapts to emerging threats. Education and training programs are provided to stakeholders to foster awareness and adherence to privacy best practices.

A numerical approach for nonlinear transmission line analysis with bidirectional coupling to lumped-element and particle-in-cell models

In this article, an iterative method for nonlinear transmission lines (TLs) based on the Lax-Wendroff method has been established to describe a bidirectional coupling model of nonlinear lumped-element models, nonlinear transmission line models, and particle-in-cell (PIC) models. The proposed self-consistent global circuit model is achieved through the introduction of the charge conservation equation at the upper plate as the Robin boundary condition and its coupling with the PIC method used for plasma simulation. The effectiveness of the proposed model is validated through five numerical experiments, including nonlinear transmission line coupling to lumped circuits, and the most general case of plasma-TLs-lumped elements model (LEM) coupling systems. This non-linear global circuit coupling model provides a powerful tool for simulating the complex behavior of various physical systems, including but not limited to capacitively coupled plasmas, vacuum electronic devices, and Z-pinches.

A Bayesian Moderated Nonlinear Factor Analysis Approach for DIF Detection under Violation of the Equal Variance Assumption

AbstractResearch has shown that multiple‐indicator multiple‐cause (MIMIC) models can result in inflated Type I error rates in detecting differential item functioning (DIF) when the assumption of equal latent variance is violated. This study explains how the violation of the equal variance assumption adversely impacts the detection of nonuniform DIF and how it can be addressed through moderated nonlinear factor analysis (MNLFA) model via Bayesian estimation approach to overcome limitations from the restrictive assumption. The Bayesian MNLFA approach suggested in this study better control Type I errors by freely estimating latent factor variances across different groups. Our experimentation with simulated data demonstrates that the BMNFA models outperform the existing MIMIC models, in terms of Type I error control as well as parameter recovery. The results suggest that the MNLFA models have the potential to be a superior choice to the existing MIMIC models, especially in situations where the assumption of equal latent variance assumption is not likely to hold.

Dynamic evolution control for the DC/DC boost converter design and implementation

This paper introduces the design and hardware implementation of the dynamic evolution control for a DC/DC boost converter. The development of the controller aims to effectively regulate the output voltage of the DC/DC boost converter with a high degree of precision. A comprehensive examination of the duty cycle formula for the boost converter is conducted using a non-linear analysis approach. This study introduces a methodology for the synthesis of a converter controller utilizing the principles of dynamic evolution control theory. The converter's output consistently aligns with the target voltage by following the dynamic evolution path determined by the designed controller. The performance evaluation of the proposed boost converter controller utilizing dynamic evolution control is being validated through the utilization of MATLAB/Simulink simulation software. The effectiveness of the proposed controller is further validated through the presentation of hardware results. The performance of the controller was evaluated by varying the values of parameters k and m.

A nonlinear analytical approach for estimating vehicle braking distance based on multi-body dynamic simulation

A nonlinear analytical approach for estimating vehicle braking distance based on multi-body dynamic simulation

Self-constructed strategy-based reinforcement LSTM approach for fiber-reinforced polymer non-linear degradation performance analysis

The performance degradation of fiber-reinforced polymer (FRP) is a typical sequential data with a highly non-linear evolution pattern. In this study, a Self-constructed strategy-based reinforcement LSTM approach (short for SCRLA) is proposed to self-accommodate the non-linear sequential data, reduce modeling burden, and improve generalization ability. SCRLA incorporates Bayesian algorithms introducing the uncertainty of hyperparameter optimization by a probabilistic distribution of implicit objectives and self-constructed a high-dimensional, reinforced machine model that can learn and predict non-linear representations. In the case study, the datasets with different properties (one consisting of finite element analysis (FEA) results and one of real experimental (EXP) data) are selected to verify the validity of the degradation performance predictions. It is shown that the reinforced LSTM based on SCRLA is more suitable for the non-linear degradation performance analysis of FRP, especially with higher prediction accuracy for EXP data. The establishment of the approach and model provides a feasible idea and framework for the prediction of composites' sequential performance.

Nonlinear modelling parameters for performance-based seismic evaluation of existing wood light-frame buildings in Canada

The mechanical behaviour of wood light-frame shearwalls is difficult to explain unless system-level performance is taken into account. Although the behaviour of wood light-frame shearwalls with wood structural panels is consistent with and represented by the behaviour of the panel to framing nail joints, comprehensive seismic evaluation guidelines for Canadian practice are currently lacking. This study presents a critical review of the available literature on the performance-based seismic evaluation of wood light-frame buildings through nonlinear analysis approach. To verify the applicability of these standards in Canada, the procedure outlined in these documents is compared to available experimental testing. Nonlinear pushover analysis is performed on two representative wood light-frame buildings in Montréal and Vancouver. Results are compared, and further discussion is provided on the adequacy of each document to Canadian practice.

A multi-physical coupling isogeometric formulation for nonlinear analysis and smart control of laminated CNT-MEE plates

This paper presents a novel and comprehensive numerical approach for nonlinear analysis and smart damping control in laminated functionally graded carbon nanotube reinforced magneto-electro-elastic (FG-CNTMEE) plate structures, taking into account multiple physical fields. The approach employs a multi-physical coupling isogeometric formulation based on Non-Uniform Rational Basis Spline (NURBS) to analyze the behavior of laminated FG-CNTMEE plate structures. It incorporates a refined zig-zag theory to accurately capture the Von Kármán nonlinear strain–displacement relationship, as well as the magneto-electro-elastic coupling properties of laminate layers. To achieve nonlinear damped responses, the smart constrained layer damping (SCLD) treatment is applied. Furthermore, to enable smart control of structures using the time-dependent passive/semi-active damping mechanism of viscoelastic materials, the formulation is transformed into the Laplace domain using the Golla–Hughes–McTavish model. The results are then converted back to the time domain through inverse techniques. The proposed approach has been rigorously validated through verification work and demonstrated its effectiveness in simulating and controlling FG-CNTMEE plates in two numerical examples.

An improved FSDT with an efficient mesh-free approach for nonlinear static analysis of FG-GOPRC beams

The aim of this paper is to enhance the First Shear Deformation Theory (FSDT) beam and apply it to investigate the linear and nonlinear static bending behavior of beams containing functionally graded graphene oxide powder-reinforced composite (FG-GOPRC). In this study, we propose an improvement to the FSDT by utilizing a high-order mesh-free approach. Unlike some existing FSDT methods, our proposed study uses a nonlinear shear deformation term coupling, which is crucial to illustrate the effect of nonlinear cases of various boundary conditions under a strong formulation, even without selective or reduced integration, resulting in lower computation costs. Using the principle of minimum potential energy, the governing equations are rewritten in a matrix–vector strong form and discretized using the Radial Point Interpolation Method with variable shape parameter (VS-RPIM) and linearized using a High Order Path Following Techniques (HOPFT). To account for the behavior of GOPRC, we utilized the modified Halpin–Tsai model to estimate the effective Young’s modulus, while the rule of mixture was employed to determine the effective Poisson’s ratio. Furthermore, the weight fractions of the graphene oxide powder (GOP) vary continuously through the thickness direction of the composite beams. To validate the proposed numerical model, we provide various comparison studies to demonstrate its robustness and accuracy. Additionally, we conduct parametric studies to examine the effects of different parameters, such as length-to-thickness ratio, GOP distribution patterns, weight fraction, and size of GOP, types of loads, and boundary conditions on the nonlinear bending behavior of FG-GOPRC beams. We also investigate the neglected term in some literature, which is of interest in our study. In summary, this paper proposes an enhanced FSDT to investigate the nonlinear static behavior of FG-GOPRC beams. The proposed model is validated through various comparison studies and parametric analyses, demonstrating its robustness and accuracy. Our study provides useful insights into the nonlinear bending behavior of FG-GOPRC beams and highlights the importance of nonlinear shear deformation term coupling.

Damping approaches in nonlinear seismic time history analysis for large mobile equipment with uplift

AbstractIn large mobile equipment in seismically active regions, seismic stability is often a decisive design criterion, and the behaviour of this large equipment, which is characterised by uplift, tilting and rocking, can only be calculated by means of nonlinear time history analyses. Here, the model damping approach has a significant influence on the results of these analyses but there are no scientific approaches for large mobile equipment with nonlinear behaviour such as uplift. In this paper, possible theoretical damping approaches for nonlinear time history analysis of structures with uplift such as large mobile equipment are discussed and numerical studies are conducted to investigate the influence of damping in the model on the concise results of the typical behaviour of large mobile equipment under seismic excitation. A suitable new approach is to be developed and a way of practical implementation is being prepared. Experimental studies on real typical bucket wheel machines will identify and validate important natural frequencies and associated damping for the numerical approach. These can be applied in numerical models using the damping approach engineered in the theoretical part. Thus, realistic results of the numerical models under nonlinear seismic time history analyses can be expected and more precise conclusions on the distinctive behaviour of large mobile equipment with uplift can be drawn.

Asymmetric effects of wellness destination and wellness facility attributes on tourist satisfaction

PropósitoEste estudio tiene como objetivo proporcionar información sobre los determinantes de la satisfacción del turismo de bienestar, adoptando así un enfoque no lineal con respecto a las relaciones entre el rendimiento a nivel de atributos de (i) atributos de instalaciones de bienestar, por un lado, y (ii) atributos de destino de bienestar, por otro lado, y la satisfacción del turista de bienestar global. Además, se calculan puntajes de rango de impacto para revelar las instalaciones de bienestar y los atributos de destino potencialmente más determinantes.Diseño/metodología/enfoqueeste estudio utiliza datos de un estudio basado en encuestas realizado entre 1,331 turistas de bienestar que participaron en actividades de turismo de bienestar en uno de los 28 hoteles con ofertas de bienestar y diez spas en Croacia. El análisis de asimetría de impacto (IAA) y el análisis de rango de impacto (IRA) se utilizan para cuantificar el potencial de los atributos de bienestar individuales para generar satisfacción e insatisfacción entre los turistas de bienestar y para realizar una clasificación de los atributos de bienestar de acuerdo con la teoría de los tres factores del cliente. satisfacción.HallazgosLos operadores de instalaciones de turismo de bienestar, así como los administradores de destinos de bienestar, no deben comprometer los niveles de calidad porque la mayoría de los atributos de bienestar tienen un potencial significativamente mayor para frustrar que para complacer a los turistas. Los factores básicos, como la limpieza, la puntualidad o la seguridad, resultaron ser los que más influyeron en los niveles de satisfacción global. En consecuencia, estos atributos no deben verse como fuentes potenciales de satisfacción y deleite del cliente, sino que deben otorgarse altos niveles de desempeño para evitar una fuerte insatisfacción. Además, en línea con investigaciones anteriores, los turistas de bienestar tienen grandes expectativas de que los destinos tengan una naturaleza preservada y hermosa, que es, con mucho, el atributo de destino más influyente. Además de un entorno seguro y un alojamiento de alta calidad, los turistas de bienestar prefieren una rica oferta cultural. Aplicando la teoría de los tres factores, una visión más matizada de la formación de la satisfacción del turista de bienestar mostró que estos atributos del destino tienen un potencial mucho mayor para crear una fuerte insatisfacción que satisfacción.OriginalidadEste es el primer estudio que aplica un enfoque de análisis no lineal a la relación calidad-satisfacción en un entorno de turismo de bienestar. Además, según el conocimiento de los autores, este es el único estudio que utilizó modelos de atributos separados para instalaciones de bienestar, por un lado, y destinos de bienestar, por el otro, en base a una muestra nacional que cubre múltiples casos (es decir, múltiples instalaciones y destinos).

A novel machine learning-based approach for nonlinear analysis and in-situ assessment of masonry

Predicting the local and global mechanical response of masonry structures or estimating their in-situ properties are critical and challenging for the design or assessment of these structures. This article presents a fast prediction/assessment model, developed using a conditional generative adversarial neural network (cGAN) to address this challenge. For the first time, the model shows to be capable of establishing a relationship between masonry microstructural features and full-field local/global mechanical response, and vice-versa, overpassing the path dependency of the non-linear mechanical problems. The strain maps and reaction forces of masonry panels are predicted at any load level from images of masonry panels, which embedded information regarding the materials properties and loading scenarios only in colours, without having any prior knowledge of the material properties and constitutive laws and without the need to access these fields in previous loading levels. Also, it is shown that the mechanical properties of masonry constituents can be predicted from full-field strain maps and loading scenarios using the developed model. This promises to become a revolutionary metamodel for the expensive finite element simulations of masonry or to support in-situ/laboratory experimental testing in the identification of masonry material properties.

Dynamic modeling and analysis of a large-scale hoop-column antenna using the referenced nodal coordinate formulation

Hoop-column antenna (HCA) is a popular type of deployable antenna in aerospace engineering. Extracting a precise model and performing a comprehensive dynamic analysis is the foundation for ensuring the HCA works properly in complex space environments. However, the multiscale characteristics and strong nonlinearities make most modeling methods invalid because of low accuracy and efficiency. Dynamic modeling and analysis are conducted for HCA constructed by beams and cables using the referenced nodal coordinate formulation in this work. The straight and initially curved beam elements and pre-tensioned cable elements are introduced based on the absolute nodal coordinate formulation. The HCA is described in a non-inertial frame to separate the overall motion and deformations. The nonlinear dynamic equations of the HCA are firstly linearized around its tensioned equilibrium configuration and natural frequencies and mode shapes are analyzed. The symmetric and antisymmetric mode shapes are observed and corresponding characteristics are revealed. The mistuning ratio is introduced to study the mistuning properties. The nonlinear dynamic responses of the HCA for orbital transfer under finite thrust are simulated. The present work provides a general dynamic modeling approach for linear and nonlinear dynamic analysis of the HCA. The numerical results also provide some guidance for the parameter design and vibration control of the HCA.