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Articles 1 - 10 of 10
Full-Text Articles in Physical Sciences and Mathematics
Theory Of Gaussian Variational Approximation For A Poisson Mixed Model, Peter Hall, J T. Ormerod, M P. Wand
Theory Of Gaussian Variational Approximation For A Poisson Mixed Model, Peter Hall, J T. Ormerod, M P. Wand
Faculty of Informatics - Papers (Archive)
Likelihood-based inference for the parameters of generalized linear mixed models is hindered by the presence of intractable integrals. Gaussian variational approximation provides a fast and effective means of approximate inference. We provide some theory for this type of approximation for a simple Poisson mixed model. In particular, we establish consistency at rate m−1/2 +n−1, where m is the number of groups and n is the number of repeated measurements.
Statistical Analysis Model Predicting Computer Use In Mathematics, Rebecca Hudson, Anne Porter, Mark Nelson
Statistical Analysis Model Predicting Computer Use In Mathematics, Rebecca Hudson, Anne Porter, Mark Nelson
Faculty of Informatics - Papers (Archive)
This paper is a report of a doctoral thesis that investigated the factors that were associated with the use of computers in secondary mathematics teaching, the choices made by teachers and learning theories guiding their teaching. Mixed methods approaches were used to triangulate the results of the study. The study was divided into three stages, the first a questionnaire completed by 114 teachers, the second was examination of current accredited courses in teacher preparation for mathematics teaching to identify what learning theories were included in subjects, and the third were interviews with 8 teachers in training and 6 experienced teachers. …
Asymptotic And Numerical Results For A Model Of Solvent-Dependent Drug Diffusion Through Polymeric Spheres, Scott Mccue, Mike Hsieh, Timothy J. Moroney, Mark I. Nelson
Asymptotic And Numerical Results For A Model Of Solvent-Dependent Drug Diffusion Through Polymeric Spheres, Scott Mccue, Mike Hsieh, Timothy J. Moroney, Mark I. Nelson
Faculty of Informatics - Papers (Archive)
A model for drug diffusion from a spherical polymeric drug delivery device is considered. The model contains two key features. The first is that solvent diffuses into the polymer, which then transitions from a glassy to a rubbery state. The interface between the two states of polymer is modeled as a moving boundary, whose speed is governed by a kinetic law; the same moving boundary problem arises in the one-phase limit of a Stefan problem with kinetic undercooling. The second feature is that drug diffuses only through the rubbery region, with a nonlinear diffusion coefficient that depends on the concentration …
A Mathematical Model For The Biological Treatment Of Industrial Wastewaters In A Cascade Of Four Reactors, Annette L. Worthy, Mark I. Nelson, Rubayyi Turki Alqahtani
A Mathematical Model For The Biological Treatment Of Industrial Wastewaters In A Cascade Of Four Reactors, Annette L. Worthy, Mark I. Nelson, Rubayyi Turki Alqahtani
Faculty of Informatics - Papers (Archive)
Many industrial processes, particularly in the food industry, produce slurriesor wastewaters containing high concentrations of biodegradable organicmaterials. Before these contaminated wastewaters can be dischargedthe concentration of these pollutants must be reduced. A method which has beenextensively employed to remove biodegradable organic matter is biologicaltreatment. In this process the wastewater (or slurry) is passed through abioreactor containing biomass which grows through consumption of thepollutants.The industrial treatment of wastewaters typically employs a reactor cascade.In a reactor cascade of n reactors the effluent stream from the ith reactor inthe cascade acts as the feed stream for the (i+1)th reactor, i.e. the nextreactor. The …
A Preliminary Investigation Of Complex Adaptive Systems As A Model For Explaining Organisational Change Caused By The Introduction Of Health Information Systems, Kieren Diment, Ping Yu, Karin Garrety
A Preliminary Investigation Of Complex Adaptive Systems As A Model For Explaining Organisational Change Caused By The Introduction Of Health Information Systems, Kieren Diment, Ping Yu, Karin Garrety
Faculty of Informatics - Papers (Archive)
This paper documents the preliminary development of a framework for evaluating organisational change processes during the implementation of an electronic nursing documentation system in residential aged care facilities. It starts with a brief outline of organisational change processes. This is followed by a more detailed exposition of the principles underlying complex adaptive systems (CAS) theory, where we explain how mathematical concepts can be used to illuminate qualitative research approaches. Finally we present some preliminary findings on the facilitators and barriers for the introduction of the electronic documentation system, explained with reference to the CAS theory, based on analysis of interviews …
Daily And 3-Hourly Variability In Global Fire Emissions And Consequences For Atmospheric Model Predictions Of Carbon Monoxide, M Mu, James Randerson, G R. Van Der Werf, L Giglio, Prasad Kasibhatla, D Morton, G J. Collatz, R S. Defries, E J. Hyer, E M. Prins, David W. Griffith, Debra Wunch, G C. Toon, V Sherlock, Paul O. Wennberg
Daily And 3-Hourly Variability In Global Fire Emissions And Consequences For Atmospheric Model Predictions Of Carbon Monoxide, M Mu, James Randerson, G R. Van Der Werf, L Giglio, Prasad Kasibhatla, D Morton, G J. Collatz, R S. Defries, E J. Hyer, E M. Prins, David W. Griffith, Debra Wunch, G C. Toon, V Sherlock, Paul O. Wennberg
Faculty of Science - Papers (Archive)
"Attribution of the causes of atmospheric trace gas and aerosol variability often requires the use of high resolution time series of anthropogenic and natural emissions inventories. Here we developed an approach for representing synoptic-and diurnal-scale temporal variability in fire emissions for the Global Fire Emissions Database version 3 (GFED3). We disaggregated monthly GFED3 emissions during 2003-2009 to a daily time step using Moderate Resolution Imaging Spectroradiometer (MODIS)-derived measurements of active fires from Terra and Aqua satellites. In parallel, mean diurnal cycles were constructed from Geostationary Operational Environmental Satellite (GOES) Wildfire Automated Biomass Burning Algorithm (WF_ABBA) active fire observations. Daily variability …
Methane Observations From The Greenhouse Gases Observing Satellite: Comparison To Ground-Based Tccon Data And Model Calculations, Robert Parker, Hartmut Boesch, Austin Cogan, Annemarie Fraser, Liang Feng, Paul Palmer, Janina Messerschmidt, Nicholas M. Deutscher, David W. Griffith, Justus Notholt, Paul O. Wennberg, Debra Wunch
Methane Observations From The Greenhouse Gases Observing Satellite: Comparison To Ground-Based Tccon Data And Model Calculations, Robert Parker, Hartmut Boesch, Austin Cogan, Annemarie Fraser, Liang Feng, Paul Palmer, Janina Messerschmidt, Nicholas M. Deutscher, David W. Griffith, Justus Notholt, Paul O. Wennberg, Debra Wunch
Faculty of Science - Papers (Archive)
We report new short-wave infrared (SWIR) column retrievals of atmospheric methane (X CH4) from the Japanese Greenhouse Gases Observing SATellite (GOSAT) and compare observed spatial and temporal variations with correlative ground-based measurements from the Total Carbon Column Observing Network (TCCON) and with the global 3-D GEOS-Chem chemistry transport model. GOSAT X CH4 retrievals are compared with daily TCCON observations at six sites between April 2009 and July 2010 (Bialystok, Park Falls, Lamont, Orleans, Darwin and Wollongong). GOSAT reproduces the site-dependent seasonal cycles as observed by TCCON with correlations typically between 0.5 and 0.7 with an estimated single-sounding precision between 0.4-0.8%. …
Retrieval Of Atmospheric Co2 With Enhanced Accuracy And Precision From Sciamachy: Validation With Fts Measurements And Comparison With Model Results, M Reuter, H Bovensmann, M Buchwitz, Jp Burrows, B Connor, Nicholas M. Deutscher, David W. Griffith, J Heymann, Gretchen Keppel-Aleks, Janina Messerschmidt, Justus Notholt, Christof Petri, J Robinson, O Schneising, V Sherlock, Voltaire A. Velazco, Thorsten Warneke, Paul O. Wennberg, Debra Wunch
Retrieval Of Atmospheric Co2 With Enhanced Accuracy And Precision From Sciamachy: Validation With Fts Measurements And Comparison With Model Results, M Reuter, H Bovensmann, M Buchwitz, Jp Burrows, B Connor, Nicholas M. Deutscher, David W. Griffith, J Heymann, Gretchen Keppel-Aleks, Janina Messerschmidt, Justus Notholt, Christof Petri, J Robinson, O Schneising, V Sherlock, Voltaire A. Velazco, Thorsten Warneke, Paul O. Wennberg, Debra Wunch
Faculty of Science - Papers (Archive)
The Bremen Optimal Estimation differential optical absorption spectroscopy (DOAS) (BESD) algorithm for satellite based retrievals of XCO 2 (the column-average dry-air mole fraction of atmospheric CO 2) has been applied to Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) data. It uses measurements in the O 2-A absorption band to correct for scattering of undetected clouds and aerosols. Comparisons with precise and accurate ground-based Fourier transform spectrometer (FTS) measurements at four Total Carbon Column Observing Network (TCCON) sites have been used to quantify the quality of the new SCIAMACHY XCO 2 data set. Additionally, the results have been compared to …
The Australian Methane Budget: Interpreting Surface And Train-Borne Measurements Using A Chemistry Transport Model, A Fraser, C C. Miller, Paul Palmer, Nicholas M. Deutscher, Nicholas B. Jones, David W. Griffith
The Australian Methane Budget: Interpreting Surface And Train-Borne Measurements Using A Chemistry Transport Model, A Fraser, C C. Miller, Paul Palmer, Nicholas M. Deutscher, Nicholas B. Jones, David W. Griffith
Faculty of Science - Papers (Archive)
We investigate the Australian methane budget from 2005-2008 using the GEOS-Chem 3D chemistry transport model, focusing on the relative contribution of emissions from different sectors and the influence of long-range transport. To evaluate the model, we use in situ surface measurements of methane, methane dry air column average (XCH 4) from ground-based Fourier transform spectrometers (FTSs), and train-borne surface concentration measurements from an in situ FTS along the north-south continental transect. We use gravity anomaly data from Gravity Recovery and Climate Experiment to describe the spatial and temporal distribution of wetland emissions and scale it to a prior emission estimate, …
An Assessment Tool For E-Government System Performance: A Citizen-Centric Model, Shatha A. Al-Haddad, Peter Hyland, Geoffrey Hubona
An Assessment Tool For E-Government System Performance: A Citizen-Centric Model, Shatha A. Al-Haddad, Peter Hyland, Geoffrey Hubona
Faculty of Informatics - Papers (Archive)
Governments worldwide have, increasingly, implemented e-government initiatives for their potential significant benefits; among which, delivering better services to citizens through increasing citizens' convenience, satisfaction, and independence; and saving their time, effort, and cost. Achieving each benefit is an objective to these governments and fulfilling each objective is considered a critical success factors. Hence, governments need to assess the extent to which they were able to obtain their preset goals. This study merely focuses on the citizens' perspective of the evaluation. However, the literature seems to lack studies that propose such a sufficient evaluation tool that has been reliably validated. Therefore, …