The Adiabatic Invariance of the Action Variable in Classical Dynamics

We consider one-dimensional classical time-dependent Hamiltonian systems with quasi-periodic orbits. It is well-known that such systems possess an adiabatic invariant which coincides with the action variable of the Hamiltonian formalism. We present a new proof of the adiabatic invariance of this quantity and illustrate our arguments by means of explicit calculations for the harmonic oscillator. The new proof makes essential use of the Hamiltonian formalism. The key step is the introduction of a slowly-varying quantity closely related to the action variable. This new quantity arises naturally within the Hamiltonian framework as follows: a canonical transformation is first performed to convert the system to action-angle coordinates; then the new quantity is constructed as an action integral (effectively a new action variable) using the new coordinates. The integration required for this construction provides, in a natural way, the averaging procedure introduced in other proofs, though here it is an average in phase space rather than over time.Comment: 8 page

Research Leadership: Should Clinical Directors be Distinguished Researchers?

Objectives: Clinical directors established research-led healthcare by combining research, teaching and clinical excellence within teaching hospitals. This research culture created high clinical standards, which benefited patients, the workforce and healthcare organisations. The current paper explores this research leadership role for clinical directors. It reviews studies arising from the theory of expert leadership (TEL), which focuses on the relationship between a leader’s core knowledge and organisational performance. More specifically, we examine the expert leader’s research track record, the associations with their organisation’s performance, and the influence of research activity on clinical excellence. Conclusion: Distinguished researchers still lead the most prestigious teaching hospitals and the most trusted departments of psychiatry in the United States where the clinical directorate structure originated. It is also known that good scholars can improve research output when appointed to leadership positions. This suggests that the clinical director’s research track record should be a consideration at a time when research is being embedded in Australia’s local health networks (LHNs). A clinical director’s leadership may influence the research performance of their department and contribute to the quality of mental healthcare

On designing observers for time-delay systems with nonlinear disturbances

This is the post print version of the article. The official published version can be obtained from the link below - Copyright 2002 Taylor & Francis LtdIn this paper, the observer design problem is studied for a class of time-delay nonlinear systems. The system under consideration is subject to delayed state and non-linear disturbances. The time-delay is allowed to be time-varying, and the non-linearities are assumed to satisfy global Lipschitz conditions. The problem addressed is the design of state observers such that, for the admissible time-delay as well as non-linear disturbances, the dynamics of the observation error is globally exponentially stable. An effective algebraic matrix inequality approach is developed to solve the non-linear observer design problem. Specifically, some conditions for the existence of the desired observers are derived, and an explicit expression of desired observers is given in terms of some free parameters. A simulation example is included to illustrate the practical applicability of the proposed theory.The work of Z. Wang was supported in part by the University of Kaiserslautern of Germany and the Alexander von Humboldt Foundation of Germany

Does progressive resistance and balance exercise reduce falls in residential aged care? Randomized controlled trial protocol for the SUNBEAM program

Introduction: Falls are common among older adults. It is reported that approximately 60% of residents of aged care facilities fall each year. This is a major cause of morbidity and mortality, and a significant burden for health care providers and the health system. Among community dwelling older adults, exercise appears to be an effective countermeasure, but data are limited and inconsistent among studies in residents of aged care communities. This trial has been designed to evaluate whether the SUNBEAM program (Strength and Balance Exercise in Aged Care) reduces falls in residents of aged care facilities. Research question: Is the program more effective and cost-effective than usual care for the prevention of falls? Design: Single-blinded, two group, cluster randomized trial. Participants and setting: 300 residents, living in 20 aged care facilities. Intervention: Progressive resistance and balance training under the guidance of a physiotherapist for 6 months, then facility-guided maintenance training for 6 months. Control: Usual care. Measurements: Number of falls, number of fallers, quality of life, mobility, balance, fear of falling, cognitive well-being, resource use, and cost-effectiveness. Measurements will be taken at baseline, 6 months, and 12 months. Analysis: The number of falls will be analyzed using a Poisson mixed model. A logistic mixed model will be used to analyze the number of residents who fall during the study period. Intention-to-treat analysis will be used. Discussion: This study addresses a significant shortcoming in aged care research, and has potential to impact upon a substantial health care problem. Outcomes will be used to inform care providers, and guide health care policies. © 2014 Hewitt et al

Modelling requirements for the design of active stability control strategies for a high speed bogie

The paper presents the findings of a study on active stability control and simulation for a railway bogie vehicle. For control design a planview partial railway vehicle model is described. This is a simplified model derived from research experience and appropriate modelling, and a frequency domain analysis illustrates the problems associated with system instability. A multi-body dynamics software, SIMPACK1, is used to generate a detailed non-linear full vehicle model for simulation and control assessment. Model order reduction methods, both empirically and analytically based, are used to simplify the linear model generated from SIMPACK for further system analysis and control designs based upon the complex model. Comparisons between the simplified plan-view model and the exported reduced-order model are presented

MAGLEV suspensions - a sensor optimisation framework

In this paper, a systematic framework for optimised sensor configurations is implemented via H∞ Loop Shaping Procedure. The optimisation framework, gives the sensor sets that satisfy predefined user criteria and the preset constraints required for the MAGnetic LEVitated suspension performance via evolutionary algorithms. The scheme is assessed via appropriate simulations for its efficacy