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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.

An integrated mixed bacterial culture consisting of four strains has been isolated by a batch enrichment technique. The cellulolytic member (strain D) is a Cellulomonas sp. and the others are non-cellulolytic. The interaction between strains D and C is pronounced and appears to involve an exchange of reducing sugars and growth factors. The symbiotic relationship of this naturally occurring mixed culture is therefore one of mutualism. The filter paper cellulase and carboxymethyl cellulase activities in extracellular fluid are high, while ?-glucosidase activity is low. The mixed culture digests a variety of lignocellulosics efficiently and is of fundamental interest in the study of microbial interrelationships. ? 1987 Society for Industrial Microbiology.

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.

In this paper, an attempt has been made to carry over known results for the finite element Galerkin method for a time dependent parabolic equation with nonsmooth initial data to an integro-differential equation of parabolic type. More precisely, for the homogeneous problem a standard energy technique in conjunction with a duality argument is used to obtain an L-2-error estimate of order O ( h(2)/t) for the semidiscrete solution when the given initial function is only in L-2. Further, for the nonhomogeneous case with zero initial condition, an error estimate of order O (h(2) log (1/h)) uniformly in time is proved, provided that the nonhomogeneous term is in L-infinity(L-2). The present paper provides a complete answer to an open problem posed on p. 106 of the book Finite Element Methods for Integro-differential Equations by Chen and Shih.

By enrichment technique, nine anaerobic mixed bacterial cultures were isolated, five of which showed stable cellulolysis. All cultures fermented cellulose and produced different fermentative products. Mixed culture BOC 25 yielded major levels of acetate and ethanol (39.6 and 12.0 mmol/l, respectively) and minor levels of propionate (2.5 mmol/l) and digested filter paper cellulose to the extent of 32.5% w/v. BOC 25 digested cellulosic and lignocellulosic substrates and produced filter paper cellulase, carboxymethyl cellulase, Avicelase and ?-glucosidase. Strain DC 25, a cellulolytic Clostridium was purified from one of the mixed cultures. The fermentation products of DC 25 from cellulose, cellobiose or glucose were ethanol, acetate, formate, H2 and CO2. ? 1990 Society for Industrial Microbiology.

Author version made available in accordance with the publisher's policy. "The final publication is available at link.springer.com”, The issue of chance correction has been discussed for many decades in the context of statistics, psychology and machine learning, with multiple measures being shown to have desirable properties, including various definitions of Kappa or Correlation, and the psychologically validated ΔP measures. In this paper, we discuss the relationships between these measures, showing that they form part of a single family of measures, and that using an appropriate measure can positively impact learning.

The value of an intrusion detection sensor is often associated with its data collection and analysis features. Experience tells us such sensors fall under a range of different types and are diverse in their operational characteristics. There is a need to examine some of these characteristics to appreciate the value they add to intrusion detection deployments. This paper presents a model to determine the value derived from deploying sensors, which serves to be useful to analyse and compare intrusion detection deployments.

This article details family size differences by socio-economic area in metropolitan South Australia and suggests that these differences may be linked to cultural differences in parenting confidence and skills, and in social supports for parenting. The paper analyses Census data on average completed family size and family size distribution in six different areas. In all age groups this shows a negative correlation between family size and the socio-economic status of the area. Secondly, based on analysis of interview data with 38 mothers and 24 fathers and a small survey of 44 parents-to-be, the article suggests that the quantitative patterns may partly reflect differences in the proportions of people in each area who see being parents and having larger families as desirable and achievable undertakings for which they have the requisite personal skills and social supports to minimise adverse impacts on their own parental health and lifestyle. The article concludes by hypothesising that differential fertility levels between groups or areas partly reflect differences in levels of confidence, skills and social support for parenting, and that a cultural “crisis in parenthood” as well as a greater focus on intensive parenting may be more widespread in higher status groups which is reflected in their lower fertility.

A precise definition of interaction behavior between services is a prerequisite for successful business-to-business integration. Service choreographies provide a view on message exchanges and their ordering constraints from a global perspective. Assuming message sending and receiving as one atomic step allows to reduce the modelers’ effort. As downside, problematic race conditions resulting in deadlocks might appear when realizing the choreography using services that exchange messages asynchronously. This paper presents typical issues when desynchronizing service choreographies. Solutions from practice are discussed and a formal approach based on Petri nets is introduced for identifying desynchronizable choreographies.

Digest caches have been proposed as an effective method tospeed up packet classification in network processors. In this paper, weshow that the presence of a large number of small flows and a few largeflows in the Internet has an adverse impact on the performance of thesedigest caches. In the Internet, a few large flows transfer a majority ofthe packets whereas the contribution of several small flows to the totalnumber of packets transferred is small. In such a scenario, the LRUcache replacement policy, which gives maximum priority to the mostrecently accessed digest, tends to evict digests belonging to the few largeflows. We propose a new cache management algorithm called SaturatingPriority (SP) which aims at improving the performance of digest cachesin network processors by exploiting the disparity between the number offlows and the number of packets transferred. Our experimental resultsdemonstrate that SP performs better than the widely used LRU cachereplacement policy in size constrained caches. Further, we characterizethe misses experienced by flow identifiers in digest caches.

Off-the-shelf packages such as SAP need to be configured to suit the requirements of an organization. Reference models support the configuration of these systems. Existing reference models use rather traditional languages. For example, the SAP reference model uses Eventdriven Process Chains (EPCs). Unfortunately, traditional languages like EPCs do not capture the configuration-aspects well. Consider for example the concept of "choice" in the control-flow perspective. Although any process modeling language, including EPCs, offers a choice construct (e.g., the XOR connector in EPCs), a single construct will not be able to capture the time dimension, scope, and impact of a decision. Some decisions are taken at run-time for a single case while other decisions are taken at build-time impacting a whole organization and all current and future cases. This position paper discusses the need for configurable process models as a basic building block for reference modeling. The focus is on the control-flow perspective. © Springer-Verlag Berlin Heidelberg 2006.

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.

The transform domain characterization of linear cyclic codes over finite fields using discrete Fourier transform (DFT) over an appropriate extension field is well known. In this paper, we extend this transform domain characterization for linear quasi-cyclic codes over finite fields. We show how one can derive a lower bound on the minimum Hamming distance of a quasi-cyclic code and decode the code upto that minimum Hamming distance using this characterization.

The subject of graph embeddings deals with embedding a finite point set in a given metric space by points in another target metric space in such a way that distances in the new space are at least as much as, but not too much more than, distances in the old space. The largest new distance to old distance ratio over all pairs of points is called the distortion of the embedding. In this paper, we will study the distortion ${\rm dist}(G,H)$ while embedding metrics supported on a given graph $G$ into metrics supported on a graph $H$ of lower characteristic, where the characteristic $\chi(H)$ of a graph $H$ is the quantity $E-V+1$ ($E$ is the number of edges and $V$ is the number of vertices in $H$). We will prove the following lower bounds for such embeddings, which generalize and improve lower bounds given in [Y. Rabinovich and R. Raz, Discrete Comput. Geom. 19 (1998), no. 1, 79--94; MR1486638 (99a:57004)]: \item{$\bullet$}If $|G|=|H|$ and $\chi(G)-\chi(H)=k, {\rm dist}(G,H)\geq g_k-1$. \item{$\bullet$}If $\chi(G)-\chi(H)=k, {\rm dist}(G,H)\geq {g_k-4\over3}$. Further, we will also give an alternative proof for lower bounding the distortion when probabilistically embedding expander graphs into tree metrics. In addition, we also generalize this lower bound to the case when expander graphs probabilistically embed into graphs of constant characteristic.

We give O(m + n) algorithms for enumerating all minimum separators as well as minimal separators in a connected chordal graph. We give a tight upper bound, n - κ(G) - 1, for the number of minimal separators in a chordal graph. An important contribution of the paper is our characterisation of minimal (minimum) separators of chordal graphs and the above results are obtained as consequences of the characterisations

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.

Wavelets offer exciting possibilities for statistical problems. The recent paper read by Donoho et al. (1994) and the many references therein highlight some of the possibilities in a statistical context. Numerous interesting applications in signal processing, computer vision, numerical analysis, applied mathematics, physics and others have been reported in the mathematical, engineering and physical literature. Some of these also discuss statistically related problems. (See, e.g., Chui, 1992, Mallat, 1989b, 1989c, 1991, Mallat and Zhong, 1992, Segmen and Zeevi, 1993 and others.)

The biochemical route is identified to be one of the simplest and cheapest means by which valuable chemicals are being synthesized. Microorganisms play a vital role in carrying out these processes. However, the kinetic studies relevant to this process is scarce. Most often inhibition effects due to either cells or substrates or products affect the performance of such processes. This paper deals with the study of various model equations for substrate inhibition kinetics. An attempt has been made to study the applicability of various model equations for substrate inhibited systems by fitting their experimental data and evaluating various parameters including the standard deviations in each case. Finally, a new model has been brought out which gives the best fit for almost all the systems. ? 1994 Springer-Verlag.

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 deals with an experimental study of free convective heat transfer from fins and fin arrays attached to a heated horizontal base. The technique of differential interferometry has been utilised and experiments have been carried out under steady state conditions. Local values of heat flux, temperature, heat transfer coefficients, local and overall Nusselt numbers have been estimated. An attempt has been made to discuss in detail the flow and heat transfer mechanisms for three cases namely an isothermal vertical flat plate, a single fin attached to a heated horizontal base and a fin array in the light of the experimental findings. Correlations are presented relating the overall Nusselt number with the relevant non-dimensional parameters in these cases. ? 1990 Springer-Verlag.

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.

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.

An analytical investigation of evaporation of laminar falling liquid film along an inclined wall is presented in this paper. The results for temperature distribution, local heat and mass Nusselt numbers and mass flow ratio are found to depend mainly on, Pr and Ao. The other physical parameters igg, ? and K are found to have only a mild effect on the results. ? 1975 Springer-Verlag.

This paper considers the reliability of a system which consists of n components connected in series, the ithcomponent being supported by (mi - 1) units in parallel and obtains the optimal policy of replacement by dynamic programming. In the case of a system consisting of identical pairs, the decision depends on the number of operable pairs. For this case sample calculations are presented. ? 1984 Springer-Verlag.

This paper considers one-dimensional heat transfer model for the freeze-coating of a polymeric substance on a continuously moving sheet and on an axially moving cylinder. Analytical expressions are obtained for the freeze-coat thickness; also presented the solutions for an upper bound on the thickness of the frozenlayer using thermodynamic equilibrium conditions. Effect of Stefan number on freeze-coat thickness is briefly discussed and also the application of the present results with an example. ? 1981 Springer-Verlag.

The present paper deals with the single step syntheses of a few aliphatic polyurethanes using some simple glycols like ethylene, propylene, 1,3- and 1,4-butylene glycols and two different bis(chloromethyl) compounds viz., 1,4-bis(chloromethyl)-2,5-dimethyl benzene (I), and 1,5-bis(chloromethyl)-2,4-dimethyl benzene (II). The glass transition temperatures, Tg, of these polymers were determined using dilatometric techniques and they ranged from -12 to -48C. The polyurethanes derived from 1,4-butylene and ethylene glycols were amorphous gums with Tg well below -30C. ? 1980 Springer-Verlag.

Will a reduction in tax evasion increase social welfare? And will evasion always be reduced by an increase in the penalty for evasion or the probability of being caught? This paper examines these two questions allowing for the asymmetric information available to the tax authority and the tax evader, and for the possibility of elastic factor supply.

The paper presents some typical results of an analysis of two-dimensional, steady-state heat conduction in coolant channels subjected to the third kind of thermal boundary conditions usually encountered in a regeneratively or dump-cooled liquid rocket engine. Duct geometries of circular, rectangular, trapezoidal and isosceles triangular cross-sections with rounded corners are considered. The solution method is based on the boundary collocation technique of linear least-squares matching using Householder reflections. The results of maximum duct wall temperatures and total heat transfer to the coolant by the present analysis vis-a-vis those by one-dimensional analysis reveal that the latter predicts higher values of maximum wall temperatures in the curved region of non-circular ducts and lower values of total heat transfer to the coolant. ? 1980 Springer-Verlag.