Sleeper [for laptop computer and live performer]

Sleeper is an 18'00" musical work for live performer and laptop computer which exists as both a live performance work and a recorded work for audio CD. The work has been presented at a range of international performance events and survey exhibitions. These include the 2003 International Computer Music Conference (Singapore) where it was selected for CD publication, Variable Resistance (San Francisco Museum of Modern Art, USA), and i.audio, a survey of experimental sound at the Performance Space, Sydney. The source sound materials are drawn from field recordings made in acoustically resonant spaces in the Australian urban environment, amplified and acoustic instruments, radio signals, and sound synthesis procedures. The processing techniques blur the boundaries between, and exploit, the perceptual ambiguities of de-contextualised and processed sound. The work thus challenges the arbitrary distinctions between sound, noise and music and attempts to reveal the inherent musicality in so-called non-musical materials via digitally re-processed location audio. Thematically the work investigates Paul Virilio’s theory that technology ‘collapses space’ via the relationship of technology to speed. Technically this is explored through the design of a music composition process that draws upon spatially and temporally dispersed sound materials treated using digital audio processing technologies. One of the contributions to knowledge in this work is a demonstration of how disparate materials may be employed within a compositional process to produce music through the establishment of musically meaningful morphological, spectral and pitch relationships. This is achieved through the design of novel digital audio processing networks and a software performance interface. The work explores, tests and extends the music perception theories of ‘reduced listening’ (Schaeffer, 1967) and ‘surrogacy’ (Smalley, 1997), by demonstrating how, through specific audio processing techniques, sounds may shifted away from ‘causal’ listening contexts towards abstract aesthetic listening contexts. In doing so, it demonstrates how various time and frequency domain processing techniques may be used to achieve this shift.

Forensic challenges in service oriented architectures

Digital forensics relates to the investigation of a crime or other suspect behaviour using digital evidence. Previous work has dealt with the forensic reconstruction of computer-based activity on single hosts, but with the additional complexity involved with a distributed environment, a Web services-centric approach is required. A framework for this type of forensic examination needs to allow for the reconstruction of transactions spanning multiple hosts, platforms and applications. A tool implementing such an approach could be used by an investigator to identify scenarios of Web services being misused, exploited, or otherwise compromised. This information could be used to redesign Web services in order to mitigate identified risks. This paper explores the requirements of a framework for performing effective forensic examinations in a Web services environment. This framework will be necessary in order to develop forensic tools and techniques for use in service oriented architectures.

Management and organisational barriers in the acquisition of computer usage skills by mature age workers

Aim: To investigate workplace cultures in the acquisition of computer usage skills by mature age workers. Methods: Data were gathered through focus groups conducted at job network centres in the Greater Brisbane metropolitan region. Participants who took part were a mixture of workers and job-seekers. Results: The results suggest that mature age workers can be exposed to inappropriate computer training practices and age-insensitive attitudes towards those with low base computer skills. Conclusions: There is a need for managers to be observant of ageist attitudes in the work place and to develop age-sensitive strategies to help mature age workers learn computer usage skills. Mature age workers also need to develop skills in ways which are practical and meaningful to their work.

Computer simulation in spine biomechanics : An application in adolescent idiopathic scoliosis

Scoliosis is a spinal deformity, involving a side-to-side curvature of the spine in the coronal plane as well as a rotation of the spinal column in the transverse plane. The coronal curvature is measured using a Cobb angle. If the deformity is severe, treatment for scoliosis may require surgical intervention whereby a rod is attached to the spinal column to correct the abnormal curvature. In order to provide surgeons with an improved ability to predict the likely outcomes following surgery, techniques to create patient-specific finite element models (FEM) of scoliosis patients treated at the Mater Children’s Hospital (MCH) in Brisbane are being developed and validated. This paper presents a comparison of the simulated and clinical data for a scoliosis patient treated at MCH.

Hybrid system simulation of computer control applications over communication networks

Discrete event-driven simulations of digital communication networks have been used widely. However, it is difficult to use a network simulator to simulate a hybrid system in which some objects are not discrete event-driven but are continuous time-driven. A networked control system (NCS) is such an application, in which physical process dynamics are continuous by nature. We have designed and implemented a hybrid simulation environment which effectively integrates models of continuous-time plant processes and discrete-event communication networks by extending the open source network simulator NS-2. To do this a synchronisation mechanism was developed to connect a continuous plant simulation with a discrete network simulation. Furthermore, for evaluating co-design approaches in an NCS environment, a piggybacking method was adopted to allow the control period to be adjusted during simulations. The effectiveness of the technique is demonstrated through case studies which simulate a networked control scenario in which the communication and control system properties are defined explicitly.