Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 12 of 12

Full-Text Articles in Physical Sciences and Mathematics

Imputation, Modelling And Optimal Sampling Design For Digital Camera Data In Recreational Fisheries Monitoring, Ebenezer Afrifa-Yamoah Jan 2021

Imputation, Modelling And Optimal Sampling Design For Digital Camera Data In Recreational Fisheries Monitoring, Ebenezer Afrifa-Yamoah

Theses: Doctorates and Masters

Digital camera monitoring has evolved as an active application-oriented scheme to help address questions in areas such as fisheries, ecology, computer vision, artificial intelligence, and criminology. In recreational fisheries research, digital camera monitoring has become a viable option for probability-based survey methods, and is also used for corroborative and validation purposes. In comparison to onsite surveys (e.g. boat ramp surveys), digital cameras provide a cost-effective method of monitoring boating activity and fishing effort, including night-time fishing activities. However, there are challenges in the use of digital camera monitoring that need to be resolved. Notably, missing data problems and the cost …


Compositions, Logratios And Geostatistics: An Application To Iron Ore, Clint Ward Jan 2015

Compositions, Logratios And Geostatistics: An Application To Iron Ore, Clint Ward

Theses: Doctorates and Masters

Common implementations of geostatistical methods, kriging and simulation, ignore the fact that geochemical data are usually reported in weight percent, sum to a constant, and are thus compositional in nature. The constant sum implies that rescaling has occurred and this can be shown to produce spurious correlations. Compositional geostatistics is an approach developed to ensure that the constant sum constraint is respected in estimation while removing dependencies on the spurious correlations. This study tests the applicability of this method against the commonly implemented ordinary cokriging method. The sample data are production blast cuttings analyses drawn from a producing iron ore …


Impact Of Higher Education Workplace Relations Requirements On Nteu Membership Density, Tulsi Laxman Panchani Jan 2010

Impact Of Higher Education Workplace Relations Requirements On Nteu Membership Density, Tulsi Laxman Panchani

Theses : Honours

The National Tertiary Education Union (NTEU) is the only union working entirely in tertiary education around Australia. The union has over twenty four thousand members comprising of academic and general staff. NTEU maintains membership records at three levels, national, state and branch. The information collected includes gender, age group, employment type and work classification. In late April 2005, Higher Education Workplace Relations Requirements (HEWRRs) legislation was introduced by the Australian government. This legislation imposed restrictions on the interaction between the universities and the union and also curtailed an automatic involvement of the union in the resolution of workplace issues. The …


Comparison And Application Of Three Decorrelation Methods Pca, Maf And Acdc, Jacqueline Ferreira Jan 2010

Comparison And Application Of Three Decorrelation Methods Pca, Maf And Acdc, Jacqueline Ferreira

Theses : Honours

Geostatistics is a branch of applied mathematics that deals with spatially correlated data. Analysing and modelling spatially correlated data can be difficult and time consuming, especially for a multivariate data set. One of the techniques used to make analysis and modelling easier involves decorrelation, whereby a linear transformation on the sample variables is used to associate the spatially correlated variables with a set of decorrelated factors which are statistically and spatially independent. PCA was one of the first multivariate techniques and is mostly used as a data reduction technique. A popular alternative decorrelation technique often used in the mining industry …


Using Decision Analytic Modelling To Simulate Pregnancy, Jeffrey Cannon Jan 2009

Using Decision Analytic Modelling To Simulate Pregnancy, Jeffrey Cannon

Theses : Honours

Decision analytic modelling enables decision makers to assess the cost-effectiveness associated with a proposed change in a cunent system without physically implementing the changes. This can be achieved by formulating a mathematical model that represents all the major events occuning in the system through fmmulas and algorithms, and estimating the likely outcomes along with their costs. This type of modelling has been identified by the State Health Research Advisory Council (SHRAC) of the Western Australian Depmiment of Health as an asset for the plmming of health care investments in the future. One such area in which the Western Australian Department …


The Extent Of Interaction Between The Scallop And Prawn Fleets In The Shark Bay Scallop Managed Fishery, John Dickson Jan 2007

The Extent Of Interaction Between The Scallop And Prawn Fleets In The Shark Bay Scallop Managed Fishery, John Dickson

Theses : Honours

The Shark Bay Managed Scallop Fishery is Western Australia's most important scallop fishery with an annual value of between $2 and $58 million. In addition to this the fishery is an important source of regional employment with approximately 160 skippers and crew employed during the 2005 season. Two separate fleets are permitted to fish for scallops in this fishery, the first consisting of dedicated scallop fishing vessels (Class A licences) and the second of prawn fishing vessels (Class B licences) that are allowed to take scallops under a catch sharing arrangement. Concerns exist over the interactions between these two fleets …


Methods For The Estimation Of Missing Values In Time Series, David S. Fung Jan 2006

Methods For The Estimation Of Missing Values In Time Series, David S. Fung

Theses: Doctorates and Masters

Time Series is a sequential set of data measured over time. Examples of time series arise in a variety of areas, ranging from engineering to economics. The analysis of time series data constitutes an important area of statistics. Since, the data are records taken through time, missing observations in time series data are very common. This occurs because an observation may not be made at a particular time owing to faulty equipment, lost records, or a mistake, which cannot be rectified until later. When one or more observations are missing it may be necessary to estimate the model and also …


Direct Sequential Simulation Algorithms In Geostatistics, Robyn Robertson Jan 2002

Direct Sequential Simulation Algorithms In Geostatistics, Robyn Robertson

Theses : Honours

Conditional sequential simulation algorithms have been used in geostatistics for many years but we currently find new developments are being made in this field. This thesis presents two new direct sequential simulation with histogram reproduction algorithms and compares them with the efficient and widely used sequential Gaussian simulation algorithm and the original direct sequential simulation algorithm. We explore the possibility of reproducing both the semivariogram and the histogram without the need for a transformation to normal space, through optimising an objective function and placing linear constraints on the local conditional distributions. Programs from the GSLIB Fortran library are expanded to …


Using Simulated Annealing In Geostatistics, Wesley Wells Jan 2002

Using Simulated Annealing In Geostatistics, Wesley Wells

Theses : Honours

Simulation methods are now used extensively for estimation and prediction in mining and petroleum industries and also in environmental management. In this thesis we describe the method of simulated annealing and examine in detail the GSLIB implementation algorithm SASJM. In the context of two case studies involving both sample and exhaustive data sets, we demonstrate this algorithm and then investigate the effect on the outcome of varying the different algorithm parameters. We also consider the effect of varying the weighting given in the simulated annealing objective function to the reproduction of each of the sample histogram and semivariogram. For the …


Change Of Support Correction In Mineral Resource Estimation, Marek J. Janas Jan 2001

Change Of Support Correction In Mineral Resource Estimation, Marek J. Janas

Theses: Doctorates and Masters

The success of any mining operation greatly, if not entirely, depends on the accuracy of prediction of recoverable mining reserves. However, prior to mining, knowledge about the distribution of the Selective Mining Unit (SMU) is limited. The SMU represents the volume on which extraction of ore takes place and on which recoverable mining reserves are based. Realistic recoverable reserve estimates can be obtained from the grade-tonnage curve that corresponds to the unknown distribution of the SMU rather than to the distribution of exploration sample data. In general, if the reserve calculation, at the given cut-off grade, is based upon exploration …


Comparison Of Median Indicator Kriging With Full Indicator Kriging In The Analysis Of Spatial Data, Donna Hill Jan 1998

Comparison Of Median Indicator Kriging With Full Indicator Kriging In The Analysis Of Spatial Data, Donna Hill

Theses : Honours

In the earth sciences, and particularly in the mining of precious metals, data distributions are often strongly positively skewed. When making decisions on the potential profitability of a gold mine, for example, the high values of the distribution are of particular importance. Indicator kriging provides estimates of cumulative distribution functions from which grade tonnage curves may be calculated. Multiple or full indicator kriging requires a semivariogram to be modelled and a kriging system of equations to be solved for each cut off. This can be time consuming and modelling indicator semivariograms at high cut-offs may be difficult because of the …


Application Of Time Series Models To Sets Of Environmental Data, Saarah Ahmed Farag Jan 1994

Application Of Time Series Models To Sets Of Environmental Data, Saarah Ahmed Farag

Theses : Honours

In environmental studies, many programs have been implemented for the purpose of examining the influence of factors on the natural environment from various sources. In the past, predictions have been obtained from a simple regression model of the data from these programs to aid in deciding whether an intervention is required in the program or policy. However, most environmental time series involve correlated dependent variables which makes it difficult to apply conventional regression analysis. This thesis compares the application of the class of transfer function models, where high correlation between dependent variables is allowed, to that of conventional regression analysis. …