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- Associate Professor Mark Nelson (6)
- Professor Brian Cullis (5)
- Dr Raymond Chambers (3)
- Associate Professor Annette Worthy (2)
- Associate Professor Kashem Muttaqi (2)
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- Dr Alison Smith (2)
- Allen B. Downey (1)
- Associate Professor Rajeev Sharma (1)
- Associate Professor Sarath Perera (1)
- Associate Professor Yan-Xia Lin (1)
- Dr Akemi Chatfield (1)
- Dr Duane Robinson (1)
- Dr Gunky Kim (1)
- Dr Hoa Dam (1)
- Dr Lei Yi (1)
- Dr Maureen Edwards (1)
- Dr Thomas Suesse (1)
- Professor David Steel (1)
- Professor Philip Ogunbona (1)
Articles 1 - 30 of 33
Full-Text Articles in Physical Sciences and Mathematics
Mpeg-7 Visual Descriptors And Discriminant Analysis, Jun Zhang, Lei Ye, Jianhua Ma
Mpeg-7 Visual Descriptors And Discriminant Analysis, Jun Zhang, Lei Ye, Jianhua Ma
Dr Lei Yi
No abstract provided.
A Fundamental Analysis Of Continuous Flow Bioreactor Models With Recycle Around Each Reactor Governed By Contois Kinetics. Iii. Two And Three Reactor Cascades, Rubayyi Alqahtani, Mark Nelson, Annette Worthy
A Fundamental Analysis Of Continuous Flow Bioreactor Models With Recycle Around Each Reactor Governed By Contois Kinetics. Iii. Two And Three Reactor Cascades, Rubayyi Alqahtani, Mark Nelson, Annette Worthy
Associate Professor Annette Worthy
The steady-state treatment of industrial wastewaters in a cascade reactor with recycle is analyzed. A number of cascades with alternative arrangements of the settling units are considered. Specifically, we consider the case when the recycle stream leaving a settling unit which is placed around a reactor goes back into the feed stream for that reactor. The Contois kinetic model is used to study the degradation of biodegradable organic materials. The steady-states for the model are found and their stability determined as a function of the total residence time in the cascade. Asymptotic solutions in the limit of large total residence …
Analysis Of A Chemostat Model With Variable Yield Coefficient: Contois Kinetics., Rubayyi Alqahtani, Mark Nelson, Annette Worthy
Analysis Of A Chemostat Model With Variable Yield Coefficient: Contois Kinetics., Rubayyi Alqahtani, Mark Nelson, Annette Worthy
Associate Professor Annette Worthy
Food processing wastewaters and slurries typically contain high concentrations of biodegradable organic matter. Before the wastewater can be discharged, the pollutant concentration must be reduced. One way to achieve this is by using a biological species (biomass) that consumes the organic matter (substrate). We investigate an unstructured kinetic model for a bioreactor with a variable yield coefficient, taking into account the death rate of the microorganisms. The growth rate is given by a Contois expression, which is often used to model the growth of biomass in wastewaters containing biodegradable organic materials. The analysis shows that the system has natural oscillations …
The Analysis Of Utility Voltage Sag Data, Victor Gosbell, D Robinson, Sarath Perera
The Analysis Of Utility Voltage Sag Data, Victor Gosbell, D Robinson, Sarath Perera
Dr Duane Robinson
No abstract provided.
A Fundamental Analysis Of Continuous Flow Bioreactor And Membrane Reactor Models With Non-Competitive Product Inhibition. Ii. Exponential Inhibition, Mark Nelson, Wei Xian Lim
A Fundamental Analysis Of Continuous Flow Bioreactor And Membrane Reactor Models With Non-Competitive Product Inhibition. Ii. Exponential Inhibition, Mark Nelson, Wei Xian Lim
Associate Professor Mark Nelson
The steady-state production of a product produced through the growth of microorganisms in a continuous flow bioreactor is presented. A generalised reactor model is used in which both the classic well-stirred bioreactor and the idealised membrane bioreactor are considered as special cases. The reaction is assumed to be governed by Monod growth kinetics subject to non-competitive product inhibition. Inhibition is modelled as a decaying exponential function of the product concentration. This reaction scheme is well documented in the literature, although a stability analysis of the governing equations has not previously been presented. The performance of a well-stirred bioreactor with microorganisms …
Analysis Of A Chemostat Model With Variable Yield Coefficient: Contois Kinetics., Rubayyi Alqahtani, Mark Nelson, Annette Worthy
Analysis Of A Chemostat Model With Variable Yield Coefficient: Contois Kinetics., Rubayyi Alqahtani, Mark Nelson, Annette Worthy
Associate Professor Mark Nelson
Food processing wastewaters and slurries typically contain high concentrations of biodegradable organic matter. Before the wastewater can be discharged, the pollutant concentration must be reduced. One way to achieve this is by using a biological species (biomass) that consumes the organic matter (substrate). We investigate an unstructured kinetic model for a bioreactor with a variable yield coefficient, taking into account the death rate of the microorganisms. The growth rate is given by a Contois expression, which is often used to model the growth of biomass in wastewaters containing biodegradable organic materials. The analysis shows that the system has natural oscillations …
A Fundamental Analysis Of Continuous Flow Bioreactor Models And Membrane Reactor Models To Process Industrial Wastewaters, Mark Nelson, Xiao Dong Chen, Easwaran Balakrishnan, Harvinder Sidhu
A Fundamental Analysis Of Continuous Flow Bioreactor Models And Membrane Reactor Models To Process Industrial Wastewaters, Mark Nelson, Xiao Dong Chen, Easwaran Balakrishnan, Harvinder Sidhu
Associate Professor Mark Nelson
No abstract provided.
A Fundamental Analysis Of Continuous Flow Bioreactor Models With Recycle Around Each Reactor Governed By Contois Kinetics. Iii. Two And Three Reactor Cascades, Rubayyi Alqahtani, Mark Nelson, Annette Worthy
A Fundamental Analysis Of Continuous Flow Bioreactor Models With Recycle Around Each Reactor Governed By Contois Kinetics. Iii. Two And Three Reactor Cascades, Rubayyi Alqahtani, Mark Nelson, Annette Worthy
Associate Professor Mark Nelson
The steady-state treatment of industrial wastewaters in a cascade reactor with recycle is analyzed. A number of cascades with alternative arrangements of the settling units are considered. Specifically, we consider the case when the recycle stream leaving a settling unit which is placed around a reactor goes back into the feed stream for that reactor. The Contois kinetic model is used to study the degradation of biodegradable organic materials. The steady-states for the model are found and their stability determined as a function of the total residence time in the cascade. Asymptotic solutions in the limit of large total residence …
A Mathematical Model For The Biological Treatment Of Industrial Wastewater In A Reactor Cascade, Rubayyi Turki Alqahtani, Mark Nelson, Annette Worthy
A Mathematical Model For The Biological Treatment Of Industrial Wastewater In A Reactor Cascade, Rubayyi Turki Alqahtani, Mark Nelson, Annette Worthy
Associate Professor Mark Nelson
Many industrial processes, particularly in the food industry, produce slurries or wastewaters containing high concentrations of biodegradable organic materials. Before these contaminated wastewaters can be discharged the concentration of the biodegradable organic pollutant must be reduced. One way to do this is to pass the wastewater through a bioreactor containing biomass which grows through consumption of the pollutant. Anaerobic conditions are often favoured for the processing of waste materials with high levels of biodegradable organic pollutants as these can be removed with low investment and operational costs. We investigate the steady state effluent concentration leaving a cascade of two reactors. …
Mathematical Analysis Of Self-Heating In Compost Piles, Harvinder Sidhu, Mark Nelson, Nadeem Ansari, Xiao Dong Chen
Mathematical Analysis Of Self-Heating In Compost Piles, Harvinder Sidhu, Mark Nelson, Nadeem Ansari, Xiao Dong Chen
Associate Professor Mark Nelson
We model the increase in temperature in compost piles or landfill sites due to micro-organisms undergoing exothermic reactions. The model incorporates the heat release due to biological activity within the pile and the heat release due to the oxidation of cellulosic materials. The heat release rate due to biological activity is modelled by a function which is a monotonic increasing function of temperature over a particular range and followed by a monotone decreasing function of temperature. This functionality represents the fact that micro-organisms die or become dormant at high temperatures. The heat release due to the oxidation reaction is modelled …
Regression Analysis Under Probabilistic Multi-Linkage, Gunky Kim, Raymond Chambers
Regression Analysis Under Probabilistic Multi-Linkage, Gunky Kim, Raymond Chambers
Dr Gunky Kim
"Linkage errors can occur when probability-based methods are used to link records from two distinct data sets corresponding to the same target population. Current approaches to modifying standard methods of regression analysis to allow for these errors only deal with the case of two linked data sets and assume that the linkage process is complete, that is, all records on the two data sets are linked. This study extends these ideas to accommodate the situation when more than two data sets are probabilistically linked and the linkage is incomplete."
Lie Group Symmetry Analysis Of Transport In Porous Media With Variable Transmissivity, James Hill, Maureen Edwards, A P S Selvadurai
Lie Group Symmetry Analysis Of Transport In Porous Media With Variable Transmissivity, James Hill, Maureen Edwards, A P S Selvadurai
Dr Maureen Edwards
We determine the Lie group symmetries of the coupled partial differential equations governing a novel problem for the transient flow of a fluid containing a solidifiable gel, through a hydraulically isotropic porous medium. Assuming that the permeability ($K^*$) of the porous medium is a function of the gel concentration ($c^*$), we determine a number of exact solutions corresponding to the cases where the concentration-dependent permeability is either arbitrary or has a power law variation or is a constant. Each case admits a number of distinct Lie symmetries and the solutions corresponding to the optimal systems are determined. Some typical concentration …
It Governance Silo In The Firm: An Analysis Of Governance Research Literature, Akemi Chatfield, Padmaharsha Wanninayaka
It Governance Silo In The Firm: An Analysis Of Governance Research Literature, Akemi Chatfield, Padmaharsha Wanninayaka
Dr Akemi Chatfield
No abstract provided.
The Analysis Of Stratified Multiple Responses, Ivy Liu, Thomas Suesse
The Analysis Of Stratified Multiple Responses, Ivy Liu, Thomas Suesse
Dr Thomas Suesse
Surveys often contain qualitative variables for which respondents may select any number of the outcome categories. For instance, for the question “What type of contraception have you used?” with possible responses (oral, condom, lubricated condom, spermicide, and diaphragm), respondents would be instructed to select as many of the outcomes that apply. This situation is known as multiple responses. When the data includes stratification variables, we discuss two approaches: (1) the “GEE” approach which uses logit models directly applying the generalized estimating equations (GEE) method (Liang and Zeger, 1986); and (2) the “GMH” approach which extends the generalized Mantel–Haenszel type estimators …
Unravelling Ecological Analysis, David Steel, Mark Tranmer, D Holt
Unravelling Ecological Analysis, David Steel, Mark Tranmer, D Holt
Professor David Steel
No abstract provided.
A Comparison Of Analysis Methods For Late-Stage Variety Evaluation Trials, Sue Welham, Beverley Gogel, Alison Smith, Robin Thompson, Brian Cullis
A Comparison Of Analysis Methods For Late-Stage Variety Evaluation Trials, Sue Welham, Beverley Gogel, Alison Smith, Robin Thompson, Brian Cullis
Dr Alison Smith
The statistical analysis of late-stage variety evaluation trials using a mixed model is described, with one- or two-stage approaches to the analysis. Two sets of trials, from Australia and the UK, were used to provide realistic scenarios for a simulation study to evaluate the different methods of analysis. This study showed that a one-stage approach gave the most accurate predictions of variety performance overall or within each environment, across a range of models, as measured by mean squared error of prediction or realized genetic gain. A weighted two-stage approach performed adequately for variety predictions both overall and within environments, but …
Enhanced Diagnostics For The Spatial Analysis Of Field Trials, Katia Stefanova, Alison Smith, Brian Cullis
Enhanced Diagnostics For The Spatial Analysis Of Field Trials, Katia Stefanova, Alison Smith, Brian Cullis
Dr Alison Smith
We report an analysis of a series of uniformity field trials using the technique proposed by Gilmour, Cullis, and Verbyla. In particular, we clarify the role of the sample variogram and present a range of enhanced graphical diagnostics to aid the spatial modeling process.We highlight the implications of the presence of extraneous variation related to commonly used agronomic practices, such as serpentine harvesting.
Research Methods And The Relevance Of The Is Discipline: A Critical Analysis Of The Role Of Methodological Pluralism, Rajeev Sharma
Research Methods And The Relevance Of The Is Discipline: A Critical Analysis Of The Role Of Methodological Pluralism, Rajeev Sharma
Associate Professor Rajeev Sharma
No abstract provided.
The Analysis Of Utility Voltage Sag Data, Victor Gosbell, D Robinson, Sarath Perera
The Analysis Of Utility Voltage Sag Data, Victor Gosbell, D Robinson, Sarath Perera
Associate Professor Sarath Perera
No abstract provided.
Assessment Of Distributed Generation Impacts On Distribution Networks Using Unbalanced Three-Phase Power Flow Analysis, Md Jan-E- Alam, Kashem Muttaqi, Danny Sutanto
Assessment Of Distributed Generation Impacts On Distribution Networks Using Unbalanced Three-Phase Power Flow Analysis, Md Jan-E- Alam, Kashem Muttaqi, Danny Sutanto
Associate Professor Kashem Muttaqi
Impacts of Distributed Generation (DG) resources on distribution networks have been studied. A Newton-Raphson algorithm based three phase unbalance power flow program has been developed to incorporate the effects of system unbalance and single phase DG injection. Power flow equations have been formulated and solved in phase coordinated form. Effects of substation load-tap changer, voltage regulator, shunt capacitor and different type of load models have been considered in the development of the program. Phase asymmetry of distribution networks has been treated by modifying the Jacobian matrix. The proposed technique has been tested on IEEE 34 bus distribution test system for …
Dynamic Modelling Of Hydroelectric Turbine-Generator Unit Connected To A Hvdc System For Small Signal Stability Analysis, Yin Chin Choo, Ashish Agalgaonkar, Kashem Muttaqi, Sarath Perera, Michael Negnevitsky
Dynamic Modelling Of Hydroelectric Turbine-Generator Unit Connected To A Hvdc System For Small Signal Stability Analysis, Yin Chin Choo, Ashish Agalgaonkar, Kashem Muttaqi, Sarath Perera, Michael Negnevitsky
Associate Professor Kashem Muttaqi
This paper presents the linearised small-signal dynamic modelling of hydroelectric turbine-generator (TG) unit with CIGRE first high-voltage direct current (HVDC) benchmark system in the synchronously rotating D-Q reference frame for small-signal stability analysis. The interaction behaviour between the hydroelectric unit and the dynamics and control of HVDC system is investigated utilising eigen-analysis,participation factor analysis and by conducting sensitivity studies. The computation of eigenvalues and eigenvectors for small signal stability analysis provides an invaluable insight onto the power system dynamic behaviour by characterising the damping and frequency of the system oscillatory modes. Theconsequences of different operating conditions, such as active and …
The Analysis Of Pattern Change In Intron Sequences, Jinda Kongcharoen, Yan-Xia Lin, Rachel Caldwell, Yiren Yang, Ren Zhang
The Analysis Of Pattern Change In Intron Sequences, Jinda Kongcharoen, Yan-Xia Lin, Rachel Caldwell, Yiren Yang, Ren Zhang
Associate Professor Yan-Xia Lin
The Generalized Bernoulli Modeling approach is used to analyze the pattern change in intron sequences of a model plant species Arabidopsis thaliana. The influence of the intron length and the number of GC on the intron sequence pattern changes is examined. Two other gene properties, the gene expression level and the protein function encoded are also assessed. Among the random sampled intron sequences,10.71% of them have been identified to have sequence pattern change. Our study shows that the number of GC and the intron length significantly influence the intron pattern change while the gene expression level and the protein function …
Automated Change Impact Analysis For Agent Systems, Aditya Ghose, Hoa Dam
Automated Change Impact Analysis For Agent Systems, Aditya Ghose, Hoa Dam
Dr Hoa Dam
Intelligent agent technology has evolved rapidly over the past few years along with the growing number of agent systems in various domains. Although a substantial amount of work in agent-oriented software engineering has provided methodologies for analysing, designing and implementing agent-based systems, recent studies have highlighted that there has been very little work on maintenance and evolution of agent-based systems. A critical issue in software maintenance and evolution is change impact analysis: determining the potential consequences of a proposed change. There has been a proliferation of techniques proposed to support change impact analysis of procedural or object-oriented systems, but to …
The Analysis Of Longitudinal Data Using Mixed Model L-Splines, S. Welham, Brian Cullis, M. Kenward, R Thompson
The Analysis Of Longitudinal Data Using Mixed Model L-Splines, S. Welham, Brian Cullis, M. Kenward, R Thompson
Professor Brian Cullis
L-splines are a large family of smoothing splines defined in terms of a linear differential operator. This article develops L-splines within the context of linear mixed models and uses the resulting mixed model L-spline to analyze longitudinal data from a grassland experiment. In the spirit of time-series analysis, a periodic mixed model L-spline is developed, which partitions data into a smooth periodic component plus smooth long-term trend.
A Comparison Of Analysis Methods For Late-Stage Variety Evaluation Trials, Sue Welham, Beverley Gogel, Alison Smith, Robin Thompson, Brian Cullis
A Comparison Of Analysis Methods For Late-Stage Variety Evaluation Trials, Sue Welham, Beverley Gogel, Alison Smith, Robin Thompson, Brian Cullis
Professor Brian Cullis
The statistical analysis of late-stage variety evaluation trials using a mixed model is described, with one- or two-stage approaches to the analysis. Two sets of trials, from Australia and the UK, were used to provide realistic scenarios for a simulation study to evaluate the different methods of analysis. This study showed that a one-stage approach gave the most accurate predictions of variety performance overall or within each environment, across a range of models, as measured by mean squared error of prediction or realized genetic gain. A weighted two-stage approach performed adequately for variety predictions both overall and within environments, but …
The Analysis Of Qtl By Simultaneous Use Of The Full Linkage Map, A. Verbyla, Brian Cullis, R Thompson
The Analysis Of Qtl By Simultaneous Use Of The Full Linkage Map, A. Verbyla, Brian Cullis, R Thompson
Professor Brian Cullis
An extension of interval mapping is presented that incorporates all intervals on the linkage map simultaneously. The approach uses a working model in which the sizes of putative QTL for all intervals across the genome are random effects. An outlier detection method is used to screen for possible QTL. Selected QTL are subsequently fitted as fixed effects. This screening and selection approach is repeated until the variance component for QTL sizes is not statistically significant. A comprehensive simulation study is conducted in which map uncertainty is included. The proposed method is shown to be superior to composite interval mapping in …
Analysis Of Yield And Oil From A Series Of Canola Breeding Trials. Part I. Fitting Factor Analytic Mixed Models With Pedigree Information, C Beeck, W Cowling, A Smith, Brian Cullis
Analysis Of Yield And Oil From A Series Of Canola Breeding Trials. Part I. Fitting Factor Analytic Mixed Models With Pedigree Information, C Beeck, W Cowling, A Smith, Brian Cullis
Professor Brian Cullis
In this paper multiplicative mixed models have been used for the analysis of multi-environment trial (MET) data for canola oil and grain yield. Information on pedigrees has been included to allow for the modelling of additive and nonadditive genetic effects. The MET data set included a total of 19 trials (synonymous with sites or environments), which were sown across southern Australia in 2007 and 2008. Each trial was designed as a p-rep design using DiGGeR with the default prespecified spatial model. Lines in their first year of testing were unreplicated, whereas there were two or three replications of advanced …
Enhanced Diagnostics For The Spatial Analysis Of Field Trials, Katia Stefanova, Alison Smith, Brian Cullis
Enhanced Diagnostics For The Spatial Analysis Of Field Trials, Katia Stefanova, Alison Smith, Brian Cullis
Professor Brian Cullis
We report an analysis of a series of uniformity field trials using the technique proposed by Gilmour, Cullis, and Verbyla. In particular, we clarify the role of the sample variogram and present a range of enhanced graphical diagnostics to aid the spatial modeling process.We highlight the implications of the presence of extraneous variation related to commonly used agronomic practices, such as serpentine harvesting.
Analysis Of Economic Data Collected In Farm Surveys, Raymond Chambers, Phillip Kokic, Nhu Che
Analysis Of Economic Data Collected In Farm Surveys, Raymond Chambers, Phillip Kokic, Nhu Che
Dr Raymond Chambers
No abstract provided.
Regression Analysis Under Incomplete Linkage, Gunky Kim, Raymond Chambers
Regression Analysis Under Incomplete Linkage, Gunky Kim, Raymond Chambers
Dr Raymond Chambers
Most probability-based methods used to link records from two distinct data sets corresponding to the same target population do not lead to perfect linkage, i.e. there are linkage errors in the merged data. Further, the linkage is often incomplete, in the sense that many records in the two data sets remain unmatched at the completion of the linkage process. This paper introduces methods that correct for the biases due to linkage errors and incomplete linkage when carrying out regression analysis using linked data. In particular, it focuses on the case where one of the linked data sets is a sample …