Approximate methods of identifying dynamic systems

Abstract Some dynamic systems exhibit curve veering behavior or avoided crossings when their natural frequencies are plotted against a system parameter, while some other show a curve crossing behavior or frequency coalescence. The curve veering behavior is also observed in disordered systems where the symmetry of the system is slightly perturbed and a mode localization takes place. In some systems while the exact analysis shows a curve crossing trend, approximate analyses show a curve veering behavior. Earlier studies have shown that there is a common pattern in curve veering systems and disordered systems. In the present study the exact analysis is recognized as representing the actual system while the approximate analysis of the same system renders it a disordered system by perturbing the eigenvalues and eigenfunctions from their true values. Since the responses of disordered systems can sometimes show violent changes for small perturbations in the system parameters, the response of a simply supported plate has been obtained both exactly and approximately using the Rayleigh Ritz method, and compared. The conclusions have far reaching implications from the point of the accuracy of the response quantities obtained by approximate methods such as finite element method, the Rayleigh Ritz and Galerkin methods.

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Resonances and Instabilities in Dynamic Systems Incorporating a Cam

Journal of Mechanical Design ◽

10.1115/1.3255006 ◽

1981 ◽

Vol 103 (4) ◽

pp. 914-921

Author(s):

D. L. Cronin ◽

G. A. LaBouff

Keyword(s):

Numerical Integration ◽

Dynamic Systems ◽

System Behavior ◽

Kinematic Constraint ◽

Approximate Methods ◽

Motion Equations ◽

Governing System ◽

Resonant Behavior

A model consisting of two oscillators coupled through a kinematic constraint is employed in this paper to investigate resonances and instabilities in dynamic systems incorporating a cam. Examination of linearized motion equations exposes parameters governing system behavior. Explored using numerical integration, Floquet analyis, and approximate methods are coupling-induced modification of conventionally-predicted resonant behavior, and two categories of subharmonic and superharmonic instability. Approximate methods described in this paper for predicting resonances and instabilities appear to function reliably and offer the potential for reduced analysis cost.

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Phase behavior of cationic and anionic surfactants at low concentrations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123878 ◽

1992 ◽

Vol 50 (1) ◽

pp. 694-695

Author(s):

E. Naranjo

Keyword(s):

Phase Behavior ◽

Structural Characterization ◽

Dynamic Systems ◽

Anionic Surfactants ◽

Intermolecular Forces ◽

Stable Form ◽

Surfactant Mixtures ◽

Low Concentrations ◽

Cationic And Anionic Surfactants ◽

General Method

Equilibrium vesicles, those which are the stable form of aggregation and form spontaneously on mixing surfactant with water, have never been demonstrated in single component bilayers and only rarely in lipid or surfactant mixtures. Designing a simple and general method for producing spontaneous and stable vesicles depends on a better understanding of the thermodynamics of aggregation, the interplay of intermolecular forces in surfactants, and an efficient way of doing structural characterization in dynamic systems.

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Improving Feeding Outcomes in the NICU: Moving From Volume-Driven to Infant-Driven Feeding

Perspectives on Swallowing and Swallowing Disorders (Dysphagia) ◽

10.1044/sasd19.3.68 ◽

2010 ◽

Vol 19 (3) ◽

pp. 68-74 ◽

Cited By ~ 9

Author(s):

Catherine S. Shaker

Keyword(s):

Intensive Care Unit ◽

Dynamic Systems ◽

Neonatal Intensive Care ◽

Well Being ◽

Dynamic Systems Theory ◽

Feeding Problems ◽

Care Giving ◽

Extremely Preterm ◽

Extremely Preterm Infants

Current research on feeding outcomes after discharge from the neonatal intensive care unit (NICU) suggests a need to critically look at the early underpinnings of persistent feeding problems in extremely preterm infants. Concepts of dynamic systems theory and sensitive care-giving are used to describe the specialized needs of this fragile population related to the emergence of safe and successful feeding and swallowing. Focusing on the infant as a co-regulatory partner and embracing a framework of an infant-driven, versus volume-driven, feeding approach are highlighted as best supporting the preterm infant's developmental strivings and long-term well-being.

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A Dynamic Systems Approach to Personality

European Psychologist ◽

10.1027//1016-9040.6.3.172 ◽

2001 ◽

Vol 6 (3) ◽

pp. 172-176 ◽

Cited By ~ 14

Author(s):

Lawrence A. Pervin

Keyword(s):

Dynamic Systems ◽

Systems Approach ◽

Biological Processes ◽

Recent Advances ◽

Dynamic View ◽

The Future ◽

History Of

David Magnusson has been the most articulate spokesperson for a holistic, systems approach to personality. This paper considers three concepts relevant to a dynamic systems approach to personality: dynamics, systems, and levels. Some of the history of a dynamic view is traced, leading to an emphasis on the need for stressing the interplay among goals. Concepts such as multidetermination, equipotentiality, and equifinality are shown to be important aspects of a systems approach. Finally, attention is drawn to the question of levels of description, analysis, and explanation in a theory of personality. The importance of the issue is emphasized in relation to recent advances in our understanding of biological processes. Integrating such advances into a theory of personality while avoiding the danger of reductionism is a challenge for the future.

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