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The performance of a tapered reactor for the continuous cultivation of bakers' yeast (SCP) from cane molasses has been compared with that of a conventional cylindrical reactor. It is found that the tapered reactor has less non-idealities (bypass and deadspace). Using the experimentally evaluated bypass and deadspace values, a model for predicting conversions of substrate (cane molasses), based on the RTD model proposed by Cholette and Cloutier has been developed. The experimental substrate conversions are found to match the model satisfactorily. ? 1991 Springer-Verlag.

The exchange of design models in the design and construction industry is evolving away from 2-dimensional computer-aided design (CAD) and paper towards semantically-rich 3-dimensional digital models. This approach, known as Building Information Modelling (BIM), is anticipated to become the primary means of information exchange between the various parties involved in construction projects. From a technical perspective, the domain represents an interesting study in model-based interoperability, since the models are large and complex, and the industry is one in which collaboration is a vital part of business. In this paper, we present our experiences with issues of model-based interoperability in exchanging building information models between various tools, and in implementing tools which consume BIM models, particularly using the industry standard IFC data modelling format. We report on the successes and challenges in these endeavours, as the industry endeavours to move further towards fully digitised information exchange.

The seminal paper of Allingham and Sandmo (1972) characterised the phenomenon of tax evasion as though it were a game of roulette, with the tax loader as an idle gambler and the government — or its tax authority — acting as a rather clumsy croupier. Much of the subsequent literature has been devoted to the development of richer models of the underlying economic problems based on the Allingham-Sandmo insights. The Neck et al. paper in this volume pursues one of the more important themes that have emerged in this literature: and understanding of the role that the underground sector plays in an economy with production is central to many policy questions that are commonly raised in taxation analysis. If we do not know what the linkage is between the public sector and the underground sector, then propositions about the linkages between the public sector and the “official” private sector are likely to be seriously misleading.

There are now more than 7 million internet banking users in Australia. Despite this substantial uptake in Australia, Australian banks continue to concentrate their respective security efforts upon internal mechanisms. Education of bank customers has not for the most part solved the fundamental flaws existent in internet banking. It is widely accepted that the weakest link in internet banking facilities is not with the banks’ internal mechanisms but with customer PC. This paper analyses the research opportunities available to improve internet banking in Australia, which research could be exported to other jurisdictions where internet banking is available.

Traffic engineering can be viewed as the mechanisms that are used to reoptimise network performance on traffic variation time scales. The traffic engineering process involves measurements, detection of performance problems, and the adjustment of routes and various quality of service mechanisms in order to restore the desired performance. Traffic engineering models are essential in this feedback loop. In this paper we provide an overview of our recent contributions to analytical models for traffic engineering of elastic traffic in internets, and discuss the role that such models could play in automated or intelligent traffic engineering.

The expert process of engineering involves application of knowledge fundamental to the engineering process at one end, and of compiled knowledge in the form of heuristics gained through many years of experience at the other. Developments in Artificial Intelligence have made the process of computer aided engineering richer by enabling the simulation of this human process of engineering, which until now has been difficult to capture. Knowledge Based Expert Systems (KBES) in engineering developed so far have addressed only narrow domains of the entire process of engineering. This paper discusses a KBES shell (IES) that integrates various AI technologies, which makes it possible to implement new problem-solving strategies required for efficient handling of the entire engineering process. Issues in the integrated process of engineering are discussed first, in order to evolve a specification for the shell. The blackboard architecture is shown to be the ideal backbone for such a shell. The details of inference techniques, the knowledge based backtracking mechanism and the DBMS used in the IES are presented. The application of the IES is demonstrated using the domain of integrated engineering of steel industrial structures as an example. This application encompasses the engineering activities of conceptual design, detailed design, documentation and construction planning. ? 1993 Springer-Verlag London Limited.

This paper describes the measurement of mean velocity and turbulence intensity using hot-wire anemometry inside the cylinder of a Diesel engine under motoring (non-firing) conditions. The effects of engine speed and compression ratio on mean velocity and turbulence intensity have been studied. In addition, turbulence scales have also been evaluated using auto-correlation function and power spectrum which are obtained from fluctuating velocity. The measurements were carried out at 4 different locations inside the piston cavity. Mean velocity and turbulence intensity are found to increase with speed. Increase in compression ratio has significantly increased the mean velocity at all crank angles. The main feature of this investigation is that the experiments have been conducted at higher compression ratios and a relatively high speed using a single high temperature straight wire probe. ? 1990 Springer-Verlag.