Honeywell (Australia)

This paper develops Lyapunov functions for power systems which have dynamic reactive power loads. These functions are extensions of earlier Lyapunov functions derived for structure preserving power system models having static loads. In order to obtain strict Lyapunov functions, the transient response of the dynamic load must have a logarithmic dependence on voltage. A Lyapunov function is initially generated using a "first integral" analysis. A Popov criterion analysis is then undertaken for comparison. The developed Lyapunov functions enable the investigation of the interaction between generator (angle) and load dynamics in multimachine power systems.

A new method is presented for reducing and solving by linear methods a class of quadratic constrained optimisation problems. The type of problem occurs in interconnected physical systems and situations characterised by the sum of quadratic functions linked successively in pairs by common variables. Transformations produce a new objective function of only the terminal variables when the objective function is stationary with respect to the linking variables. This reduced objective function is optimised with most original constraints absorbed in the transformations themselves and those remaining form a single matrix constraint, also in the terminal variables, allowing application of undetermined multipliers to formulate an eigenvalue problem, the eigenvector solution of which allows the use of standard linear techniques from there onwards. Two different types of example are given: optimising data flow in computer networks and a new method for the design of broadband multilayer absorbers with specified included layer(s).

A stability analysis of parametric phase-locked subharmonic tunnel-diode circuits capable of bistable phase operation has been made. A new type of computer-produced stability-chart plot shows regions of amplification\for desired harmonics used in directional-flow logic circuits, to allow design for subharmonic pumping.

Tunnel-diode parametric phase-locked oscillators may be used as very fast memory elements, and excessive pumping frequencies can be avoided by using subharmonic pumping. The effect of the small capacitive and inductive couplings between diodes used closely in quantity has been investigated. Computed pumping eigenfrequencies for the array can be significantly different from those when coupling effects are neglected.

The DRAMA Environment provides an API for distributed instrument software development. It originated at the Anglo-Australian Observatory (now Australian Astronomical Observatory) in the early 1990s, in response to the need for a software environment for large distributed and heterogeneous systems, with some components requiring real-time performance. It was first used for the AAO's 2dF fibre positioner project for the Anglo-Australian Telescope. 2dF is still in use today, but has changed dramatically over time. DRAMA is used for other AAO systems and is or has been used at various other observatories looking for a similar solution. Whilst DRAMA has evolved and many features were added, there had been no big changes. It was still a largely C language based system, with some C++ wrappers. It did not provide good support for threading or exceptions. Ideas for proper thread support within DRAMA have been in development for some years, but C++11 has provided many features which allow a high quality implementation. The opportunity provided by C++11 has been taken to make significant changes to the DRAMA API, producing a modern and more reliable interface to DRAMA, known as DRAMA2.

This paper presents the application of the asymptotically positive realness constraint (APRC) in the stabilization for interconnected systems with a descriptor system approach. Handling parallel redundant subsystems that have unknown splitting ratios is an essential part of this development. We have introduced the parallel masking technique in previous work whereby the APRC and the dissipation inequalities are applied to different hierarchies of subsystem interconnections. In this work, the dissipativity criterion for parallel splitting systems is derived from a transformed descriptor system with the employment of a specially structured storage function. The pre-heating an desilication unit operation in an alumina refinery is simulated to illustrate the theoretical results.

An investigation has been made into the stability of compressor blade flutter in separating flow in the presence of external perturbations. The fluttering blade is an example of a hysteretic system governed by a non-linear difference-differential equation for which an analytical approach is not possible and for which the authors originally proposed this new treatment. For design purposes a digital computer has been used to produce stability diagrams under specified conditions including blade torsion. The solution for the response is also available if required. The method involves forming the non-linear feedback analogue to the blade system and which has behaviour governed by the same equation as that studied. The stability is then studied on a digital computer in the presence of small external perturbations by means of a dual input describing function applied to the analogous feedback system with consideration given to the aerodynamic phase lag involved and initially small blade torsional motion.

Digitalization provides new ways to develop and deliver training material to build competency that are superior to traditional methods in terms of learning outcomes, accessibility, and cost-effectiveness. This chapter explores the opportunities and challenges in enabling and empowering the workforce through the considered adoption of digital technology. It describes the ways in which technology can help build and maintain a competent workforce. Traditional approaches to skilling the workforce based on structured training courses and informal knowledge sharing fall short in face of increased demand and high staff turnover. The chapter examines how the key benefits of digitalization in the areas of information access, communication, and decision making can transform key roles in an industrial enterprise to improve the efficiency, reliability, and safety of the workforce. There are several challenges that need to be addressed for digitalization of the workforce to be successful and sustainable.