Structural Dynamic Model Research Articles

Fitting Single- and Multiple-Indicator STARTS Models as Dynamic Structural Equation Models

The STARTS model is a structural equation model that decomposes individual differences in a longitudinally assessed variable into a time-invariant stable component, a time-varying autoregressive component, and a time-point specific state component. Typically, the model is estimated with Maximum Likelihood in standard SEM software. Here, we show how different STARTS models (the single-indicator univariate and multivariate and the multiple-indicator univariate model) can be incorporated into the Dynamic Structural Equation Model framework. We use the data of an experience sampling study to illustrate the expositions and we provide codes to fit the models in Mplus. As the DSEM parameters are estimated with a Bayesian approach, we also report the results of three simulation studies in which we examined the statistical properties of the parameter estimates obtained in the DSEM framework. Finally, we discuss how to estimate variants of the STARTS model and we make suggestions for future applied and methodological research.

Self-esteem and social interactions in daily life: An experience sampling study

Theory and empirical evidence suggest that self-esteem and the quality of social relationships are mutually related, however, little is known about the dynamic short-term association in daily life. Experience sampling data of 232 Dutch Master’s students ( M age = 24.6, SD age = 2.7) was collected across four waves; each consisting of 14 days of four daily assessments (23,107 data points). We applied Dynamic Structural Equation Modeling to study the within-day associations between momentary self-esteem (assessed in the morning and evening) and social interactions (anticipated and experienced). First, results showed that quality of social interactions during the day was associated with evening, but not morning self-esteem. Second, positive anticipation of social interactions was associated with morning, but not with evening self-esteem. Third, trait self-esteem did not moderate the within-day associations. Together, results suggest that when having higher self-esteem, people anticipate more positive social interactions at the same time, but they do not experience more positive social interactions later on. Having but not anticipating more positive social interactions seems to contribute to higher self-esteem later on. Differentiating between anticipated and experienced interactions and using multiple daily assessments helps obtain a more fine-grained understanding of the dynamic processes between self-esteem and social interactions.

Structural dynamic constitutive model of uncompacted saturated loess based on experimental results

Structural dynamic constitutive model of uncompacted saturated loess based on experimental results

Meadows or asphalt road – Does momentary affective well-being vary with immediate physical environment? Results from a geographic ecological momentary assessment study in three metropolitan areas in Germany

We investigated the association between the immediate physical environment of individuals and individual fluctuations of momentary affective well-being in everyday life with a focus on medium sized metropolitan areas in Europe representing a typical living environment of a large proportion of the world’s population. The sample comprised 365 individuals (54.8 % female) with participants ranging from 14.08 to 88.27 years of age (M = 43.9, SD = 20.9). In an geographic ecological momentary assessment (GEMA), participants were prompted six times a day on at least 9 days over the course of 3 weeks, covering a total of six weekdays and three weekend days on mobile phones to report their momentary affective well-being. Urban land use categories (forest, water, urban green) were assessed with GPS-localization as environmental variables. Additionally, sunshine, rainfall, whether participants were inside or outside as well as whether they were alone or had company were included into the analyses.We used dynamic structural equation modelling to model the inter- and intraindividual differences as well as fluctuations and assess potential covariates while acknowledging the autoregressive nature of affect.The results showed that on individual level, fluctuations of momentary affective well-being were associated with sunshine, having company and travelling. No significant association emerged for urban green, forest, and water neither within individuals nor between. Methodological as well as conceptual implications are discussed and an interpretation of the present findings are provided.

ANCF-based modelling of rigid-flexible coupling of helicopter flexible rotor blades

Abstract A high-precision rotor structure dynamic model applicable to a variety of helicopter blade hub structures is established considering rotor blade flexible deformation. The absolute nodal coordinate method is applied to the traditional rotor blade rigid-flexible coupling dynamics model, making the new model applicable to both fully articulated rotor blades and other advanced blade hub structures. No small-volume assumptions were made in the modelling process. Both Green’s strain expression under finite deformation and the geometrical relation of elastic deformation motion based on the absolute nodal coordinate method are used to derive the blade strain energy, kinetic energy, and the external load virtual work. The rotation angle at the articulation constraint at the root of the blade coupled with the elastic deformation degrees of freedom of the blade in three independent rigid body degrees of freedom, respectively. The rotor blade rigid-flexible coupling dynamics equations were established according to the Hamilton action principle. The time-domain simulation is carried out under a free single pendulum and fixed rotational speed/fixed torque for the established flexible blade model, which verifies the validity and high accuracy of the rigid-flexible coupling articulation model of the flexible rotor blade and the blade hub.

Numerical investigation on transonic flutter characteristics of an airfoil with split drag rudder

In this paper, a series of flutter simulations are carried out to investigate the effects of split drag rudder (SDR) on the transonic flutter characteristic of rigid NACA 64A010. A structural dynamic model addressing two-degree-of-freedom pitch-plunge aeroelastic oscillations was coupled with the unsteady Reynolds-averaged Navier-Stokes equations to perform flutter simulation. Meanwhile, the influence mechanism of SDR on flutter boundary is explained through aerodynamic work and the correlated shock wave location. The results show that the SDR delays the shock wave shifting downstream, and the Mach number corresponding to reaching freeze region increases as the split angle increases. Therefore, the peak value of aerodynamic moment coefficient amplitude and the sharp ascent process of phase occurs at higher Mach number, which leads to the delay in the occurrence of the transonic dip. Besides, before the transonic dip of airfoil without SDR occurs, the aerodynamic moment phase of airfoil with the SDR decreases slowly due to the decrease in the speed of shock wave moving downstream. This results in an increased flutter speed when employing the SDR before the transonic dip of airfoil without SDR occurs. Meanwhile, the effects of asymmetric split angles on the transonic flutter characteristics are also investigated. Before the transonic dip of airfoil without SDR occurs, the flutter characteristic is dominated by the smaller split angle.

Mitral annular dynamics after transcatheter edge-to-edge repair for functional mitral regurgitation: comparison with surgical annuloplasty

Abstract Background Transcatheter edge-to-edge repair (TEER) is a recently emerged therapeutic option for functional mitral regurgitation (FMR). Although the mitral annular shape and function may play an important role in the pathophysiology of FMR, few reports have evaluated the impact of TEER. We sought to investigate the impact of TEER on the mitral annulus and its motion in FMR compared with that of mitral annuloplasty (MAP). Methods Using three-dimensional transesophageal echocardiography, we evaluated the mitral annular morphology and dynamic motion in patients who underwent TEER or MAP before and after the procedures. Mitral annulus analysis was performed by a semi-automatic program to create a dynamic model of the three-dimensional structure, where the end-systolic annular structure was semi-automatically annotated and manually corrected, followed by automatic tracking of the annulus throughout the cardiac cycle . The mitral annular parameters such as mitral annular diameters, area, circumference, and height at all frames were automatically calculated from the model. In order to align the cardiac phase in each patient (i.e. to set the start and the end of diastole and systole at the same time for all patient), data were spline-interpolated to 100 systolic and 200 diastolic frames and then statistically analyzed. The dynamic changes of the parameters during the cardiac cycle were calculated as (maximum – minimum value) / maximum value after the interpolation. Results Patients who underwent TEER (n=20, 69±15 years, 40% female) and those who underwent MAP (n=16, 64±11 years, 6% female) had similar echocardiographic characteristics before the procedures. The maximum anteroposterior diameter and annulus area decreased after both TEER and MAP, while the intercommissural diameter decreased only after MAP but not after TEER. After TEER, the dynamic change in anteroposterior diameter throughout the cardiac cycle tended to decrease (p=0.055), while intercommissural change rather increased (p=0.049), resulting in preserved change in annulus area (p=0.74). After MAP, changes in both diameters and area decreased significantly (all p<0.05). MAP was associated with postoperative mitral annulus area immobility after adjustment (p=0.030). Conclusions The dynamic motion of the mitral annulus in patients with FMR was better preserved after TEER than after MAP. There was a decreasing trend in anteroposterior motion, which was compensated for by intercommissural motion after TEER. Future studies are needed to determine the association of these results with cardiac function and prognosis.

КЕРУВАННЯ ДИНАМІКОЮ ІМПУЛЬСНОГО ПЕРЕТВОРЮВАЧА З М’ЯКИМ ПЕРЕМИКАННЯМ, ЩО ПРАЦЮЄ НА ДУГОВЕ НАВАНТАЖЕННЯ

Issues of design and research of energy-efficient and reliable semiconductor DC voltage converters for wide application in power supply devices of arc plasmatrons used in plasma metal cutting installations are considered. An estimated structural dynamic model of a soft-switching DC converter with a closed-loop control system combining the power part and the control system, intended for use as part of the latter as a digital module, was built. A technique is proposed and methods of controlling the converter are found, which provide the specified duration of transient processes, the permissible value of load current pulsations in a quasi-steady mode and the astatism of the output current, which confirms the correctness of the proposed technique. A prototype of a pulse stabilizer with digital control was made. The results of experimental studies of the sample confirm the effectiveness of the developed control device, namely the achievement of the specified duration of transient processes caused by a step change in the load current, close to 10-12 periods of conversion and astatism of the output current. It is shown that the application of a pulse stabilizer, in which a digital control loop is used, has significant advantages compared to analog options and has the advantages of a strategic plan. The use of combined control allows you to significantly reduce the requirements for the overall gain of the main control channel, which greatly facilitates the choice of sequential digital correction. Research results may be of interest to specialists in the field of power electronics, power supply systems of autonomous objects and control systems. References 14, figures 11. Key words: automatic control system, digital controller, external disturbance, plasma, robustness, optimization.

Dynamic Structural Equation Modeling with Cycles

Cyclical phenomena are commonly observed in many areas of repeated measurements, especially with intensive longitudinal data. A typical example is circadian (24-hour) rhythm of physical measures such as blood pressure, heart rate, glucose level, and alertness. This paper focuses on positive affect, which is a common measure in psychological studies and for which circadian rhythm has been observed but not analyzed by modern statistical methods. The paper demonstrates that a large new analysis arsenal is available for analysis of cyclical features in intensive longitudinal data. This can help researchers extract more information from their data to get more valid estimates of coupled processes and to get new theoretical insights into circadian rhythms of mood. To assist in this effort, the analyses are based on general models with a rich set of features while still being accessible without an unduly steep learning curve. Scripts for the Mplus software are available for all the analyses presented.

Examining the moderating role of depressive symptoms on the dynamic interplay between cognitive reappraisal and rumination: Evidence from experience sampling

The dynamic view of emotion regulation (ER) posits that ER is a temporally dynamic process unfolding over time. Cognitive reappraisal and rumination, two extensively investigated ER strategies, are implicated in depression. However, it remains unclear whether these two strategies exhibit reciprocal relations in real-world contexts, and whether such relations vary across baseline depressive symptoms. To address this, we conducted two experience sampling studies and applied residual dynamic structural equation modeling (RDSEM). Results of the RDSEM revealed significant bidirectional associations between cognitive reappraisal and rumination in the Chinese sample, whereas in the Belgian sample, only a unidirectional relationship was found where rumination predicts subsequent cognitive reappraisal. Additionally, both strategies demonstrated stable autoregressive effects. Interestingly, higher depressive symptoms predicted a lower autoregressive effect of cognitive reappraisal within the Chinese sample, while this was not the case in the Belgian sample. These findings highlight the importance of targeting factors such as dynamics in ER and its relationship with depression symptoms.

Monitoring Crop Condition at Gield Scales and at a Daily Time Step Using Synthetic Aperture Radar (SAR)

Operations that rely on optically-based Normalized Difference Vegetation Index (NDVI) to track crop productivity, are negatively impacted by cloud cover. In this research, parameters from Synthetic Aperture Radar (SAR) imagery were calibrated to NDVI with the targeted outcome to integrate SAR into Canadian crop monitoring services. Data from fully polarimetric RADARSAT-2 and dual-polarization Sentinel-1B imagery were calibrated to Sentinel-2 NDVI. Random Forest Regression (RFR) and Least Squares Boosting (LSBoost) were tested to calibrate SAR to NDVI (SARcal-NDVI) for six crops (corn, canola, soybeans, wheat, oats and barley). RADARSAT-2 provided the best fit with R2 exceeding 0.84 for canola, 0.87 for wheat and 0.90 for corn and soybeans. Correlations were lower for oats (R2 of 0.72–0.77) and barley (R2 of 0.43–0.64) due to a limited number of fields. Although a global model yielded lower correlations (R2 of 0.80), this model would be easier to implement into operations. Total power, the first and second eigenvalues and VH backscatter were important in reducing model error. The SARcal-NDVI and Growing Degree Days were then integrated into a Crop Structure Dynamic Model to produce daily estimates of crop condition, at field scales. The next step is to test if these daily estimates of crop condition can improve crop yield forecasting for the Canadian agriculture sector.

Estimation of demographics of self-sustaining groups of pied flycatcher <i>Ficedula hypoleuca</i> (Passeriformes: Muscipapidae) taking into account the long-term dynamics of the population breeding in the Tomsk oblast (Western Siberia)

We present the main demographic parameters of the Western Siberian pied flycatcher population, nesting in natural habitats, at different stages of population dynamics. The average values, range, boundaries, and direction of changes in the survival of sexually mature individuals, fecundity, and the encounter probability at different ages were analyzed. Using matrix models of population structure and population dynamics, an estimate of the true survival rate of fledglings is given. The range of values of demographic parameters that characterize viable groups of the studied bird species is indicated.

Daily Associations between Parental Warmth and Discipline and Adolescent Conduct Problems and Callous-Unemotional Traits.

Past longitudinal research has demonstrated links between parenting behaviors and adolescent conduct problems (CP) and callous-unemotional (CU) traits on macro timescales (e.g., years). Less is known about daily fluctuations in parenting behaviors and adolescent CP and CU traits, as well as their daily associations on a micro timescale. This study investigated thedaily reciprocal associations between three key dimensions of parenting behaviors-parental warmth, inconsistent discipline, and non-harsh discipline-and adolescent CP and CU traits, and explored potential moderating effects of person-mean levels of these parenting behaviors on within-person cross-day links. Participants included an ethnically-racially diverse low risk community sample of 86 adolescents (Mage = 14.5years, 55% female, 45% non-White) who completed daily reports over 1month regarding their perceived parenting behaviors and their own levels of CP and CU traits (2056 total observations). Results from dynamic structural equation modeling showed that at the within-person level, higher than average levels of inconsistent discipline were linked to higher than average levels of CU traits the next day. Among adolescents with higher person-mean levels of parental warmth and non-harsh discipline, daily parental warmth and non-harsh discipline were protective against CU traits. Moreover, among adolescents with higher person-mean levels of parental warmth, adolescent CU traits also evoked lower parental warmth the next day. These findings have significant implications for understanding daily fluctuations in parenting behaviors and adolescent CP and CU traits, and inform novel parenting-based interventions that capitalize on recent advances in mobile and other technology.

Efficient data-driven nonlinear system identification for structural health monitoring: A proof-of-principle study

Structural health monitoring (SHM) is the process of detecting damage in structures. Typically, the damage-sensitive feature identification is based on fitting some models to the measured system response data. The parameters of these models or the prediction errors associated with these models then become the desired damage-sensitive features. Real-world structures usually exhibit significant nonlinear behaviors. Data-driven nonlinear system identification (NSI) is essential to obtain accurate models of structural dynamics for reliable damage detection. However, on the one hand, the data acquisition of real-world structures for damage detection is usually difficult or scarce. On the other hand, NSI generally needs to solve a nonlinear optimization problem that requires more computational time for convergence than linear system identification. Data efficiency and computational efficiency become two critical challenges in data-driven NSI. To address these challenges, this work presents a proof-of-principle study on developing a meta learning-based method for efficient data-driven NSI. Specifically, the meta learning algorithm leverages a previously collected database of similar but different systems to learn the meta-knowledge about how to identify a new system, enabling a fast identification/modeling with limited data. Numerical simulations are performed to validate the method on fundamental nonlinear dynamical systems widely seen in civil engineering. It is observed that the presented meta learning-based method outperforms the conventional method in terms of both data and computational efficiency. Limitations of this work are further discussed.

Electromechanical coupling optimization for a sandwich beam activation using piezoceramics

Sandwich beams composed of two stiff carbon fiber skins and a viscoelastic core are often used to passively dissipate energy through the activation of shearing in a specific frequency range. Semi-active or active energy dissipation can be made possible on those structures adding piezoelectric patches, coupling mechanical vibration energy and electrical energy. J.L. Guyader et al. [jsv, 1978] theorized a frequency dependent equivalent dynamic model of a sandwich structure, recently extended to the homogenization of anisotropic multi-layers by F.Marchetti et al. [jsv, 2020]. This frequency-dependent stiffness of the beam has to be taken into account in the piezoceramic thickness definition in order to optimize the global electromechanical coupling coefficient. An analytical model is derived from the works of F.Marchetti et al. and adapted to predict the first vibration mode of a finite cantilever beam instrumented with a piezoelectric patch. The electromechanical coupling evolution is then calculated with the proper boundary conditions and for different PZT ceramic thicknesses. This model is furtherly used to define the best transducer configuration for a given sandwich structure beam.

Picometer-Level In Situ Manipulation of Ferroelectric Polarization in Van der Waals layered InSe.

Ferroelectric 2D van der Waals (vdW) layered materials are attracting increasing attention due to their potential applications in next-generation nanoelectronics and in-memory computing with polarization-dependent functionalities. Despite the critical role of polarization in governing ferroelectricity behaviors, its origin and relation with local structures in 2D vdW layered materials have not been fully elucidated so far. Here, intralayer sliding of approximately six degrees within each quadruple-layer of the prototype 2D vdW ferroelectrics InSe is directly observed and manipulated using sub-angstrom resolution imaging and in situ biasing in an aberration-corrected scanning transmission electron microscope. The in situ electric manipulation further indicates that the reversal of intralayer sliding can be achieved by altering the electric field direction. Density functional theory calculations reveal that the reversible picometer-level intralayer sliding is responsible for switchable out-of-plane polarization. The observation and manipulation of intralayer sliding demonstrate the structural origin of ferroelectricity in InSe and establish a dynamic structural variation model for future investigations on more 2D ferroelectric materials.

Structural System and Computational Dynamic Model of a Life-Saving Multi-Storey Building with a Kinematic Seismic Isolation System

Introduction. In design of a life-saving multi-storey building, a seismic isolation system in the form of the kinematic supports is used to ensure the seismic resistance and reduce the seismic loads. The structural system, the computational dynamic model and the results of the intermediate in-situ tests of a life-saving multi-storey building with a kinematic seismic isolation system being built in Grozny have been analysed in the article.Materials and Methods. The research included modeling and computation of the structural system of a building with a kinematic seismic isolation system. In-situ tests were carried out to confirm the working capacity of the seismic isolation system connections.Results. A multi-storey life-saving building was designed according to a frame-core wall structure, where the vertical load-bearing elements were core walls, columns and connections between the columns in the form of the stiffening diaphragms. The high-rise part of a building was designed using a kinematic seismic isolation system consisting of the seismic isolating concrete-filled steel tubular supports. The results of the calculations of the main and specific load combinations and internal forces in the load-bearing structures have been presented.Discussion and Conclusion. The research has shown that the use of the developed structural system of seismic isolation with kinematic supports makes it possible to reduce the seismic loads and the total weight of a building and at the same time to increase its mechanical reliability and safety. The conducted intermediate in-situ tests have confirmed the working capacity of the joints connecting the supports with the monolithic reinforced concrete structures of a building, which makes it possible to implement the kinematic seismic isolation supports into the construction industry practices.

A novel dynamic structural adaptive multivariable grey model and its application in China's solar energy generation forecasting

Accurately predicting China's solar energy generation is crucial for energy planning and environmental protection. However, the nonlinearity and complexity of the data pose challenges to prediction. This article proposes a dynamic structural adaptive multivariate grey model to overcome these challenges. The model constructs a dynamic nonlinear correction function with an uncertain structure that can adaptively adjust to the data characteristics. Additionally, the Gaussian function is utilized to derive the time response function, overcoming the mechanism defects present in traditional multivariate grey models. The whale optimization algorithm is applied to optimize the background value of the model, improving accuracy. The model is compatible with 14 classical models via parameter changes and has strong compatibility. The results show that the fitting error and test error of the model are 0.23 % and 1.95 % respectively, which is significantly better than the other 11 methods, indicative of strong robustness and accuracy. The forecast indicates that China's solar energy generation will experience a consistent upward trajectory from 2023 to 2030, with an average annual growth rate of 12.11 %. This study significantly contributes to the advancement of the theory of multivariate grey dynamic prediction and provides essential data support for strategic planning within China's solar power industry.

Dynamic coupling of maternal sensitivity and toddlers' responsive/assertive behaviors predicts children's behavior toward peers during the preschool years.

We examined the extent to which dynamic coupling of (a) maternal sensitivity and (b) children's responsive and assertive behaviors toward mothers during a semistructured play session predicts children's responsive and assertive behavior toward an unfamiliar peer at 39 months and a close friend at 58 and 66 months. Maternal and child behaviors were rated in 30-s epochs during play when children were 32 months old (Time 1; N = 128; 66 girls). Children were rated on their responsiveness and assertiveness toward an unfamiliar peer in the early preschool years (Time 2) and toward a friend in the late preschool years (Time 3). Residual dynamic structural equation models showed that stronger positive contemporaneous coupling of maternal sensitivity and children's responsiveness in a given 30-s epoch of the play session predicted greater observed responsiveness toward a friend in the late preschool years, after controlling for mean levels of maternal sensitivity and child responsiveness. On the other hand, positive contemporaneous coupling of maternal sensitivity and child assertiveness predicted children's higher levels of observed assertiveness toward an unfamiliar peer in the early preschool years, after controlling for mean levels of maternal sensitivity and child assertiveness. Results suggest that the dynamic coupling of specific positive behaviors during mother-child interaction may provide children with social scripts to draw on in diverse peer contexts. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Innovation in family businesses: Exploring the influence of entrepreneurial orientation and absorptive capacity on innovative capacity

Firms’ innovation positively affects their competitiveness and thus their financial performance. To bridge the research gap in the theoretical framework of dynamic capabilities and respond to the call for papers to explore new ways of analyzing innovation in family businesses, this study investigates how entrepreneurial orientation and absorptive capacity influence innovative capacity in family firms. Data from 156 family firms are analyzed using the theoretical framework of dynamic capabilities and structural equation modeling. The results reveal that both entrepreneurial orientation and absorptive capacity influence innovative capacity and that this influence is greater when both capabilities act together than when they act individually. This study confirms that entrepreneurial orientation and absorptive capacity are antecedents of innovative capacity. Moreover, entrepreneurial orientation has a greater influence on innovative capacity than absorptive capacity does.