Browsing Doctoral Degrees (Applied Mathematics) by Issue Date
Now showing items 120 of 55

Partial exchangeability and related topics.
(1991)Partial exchangeability is the fundamental building block in the subjective approach to the probability of multitype sequences which replaces the independence concept of the objective theory. The aim of this thesis is ... 
Aspects of graph vulnerability.
(1994)This dissertation details the results of an investigation into, primarily, three aspects of graph vulnerability namely, lconnectivity, Steiner Distance hereditatiness and functional isolation. Following the introduction ... 
Modelling the physical dynamics of estuaries for management.
(1996)South African estuaries are characterised by highly variable inflows owing to the semiarid nature of the land mass which they drain. The interaction of this variability with that of the marine environment (seasonality, ... 
2generations of the sporadic simple groups.
(1997)A group G is said to be 2generated if G = (x, y), for some nontrivial elements x, y E G. In this thesis we investigate three special types of 2generations of the sporadic simple groups. A group G is a (l, rn, n )generated ... 
Developing an integrated decision support system for an oil refinery.
(1998)This thesis considers the problem of residue upgrading operations in an oil refinery. Visbreaking is a residueupgrading process that improves profitability of a refinery. The economics of converting the heavy residue ... 
A modelling approach for determining the freshwater requirements of estuarine macrophytes.
(1998)Increased abstraction of water in the catchment results in a reduced or altered pattern of river flow and this holds serious consequences for the downstream estuarine ecosystem. In South Africa this is a serious concern ... 
Interative approaches to convex feasibility problems.
(2001)Solutions to convex feasibility problems are generally found by iteratively constructing sequences that converge strongly or weakly to it. In this study, four types of iteration schemes are considered in an attempt to ... 
Wadley's problem with overdispersion.
(2009)Wadley’s problem frequently emerges in dosagemortality data and is one in which the number of surviving organisms is observed but the number initially treated is unknown. Data in this setting are also often overdispersed, ... 
Relativistic radiating stars with generalised atmospheres.
(2010)In this dissertation we construct radiating models for dense compact stars in relativistic astrophysics. We first utilise the standard Santos (1985) junction condition to model Euclidean stars. By making use of the ... 
Doublediffusive convection flow in porous media with crossdiffusion.
(2011)In this thesis we study doublediffusive convection and crossdiffusion effects in flow through porous media. Fluid flows in various flow geometries are investigated and the governing equations are solved analytically ... 
Asymptotic analysis of singularly perturbed dynamical systems.
(2011)According to the needs, real systems can be modeled at various level of resolution. It can be detailed interactions at the individual level (or at microscopic level) or a sample of the system (or at mesoscopic level) and ... 
Fischer Clifford matrices and character tables of certain groups associated with simple groups O+10(2) [the simple orthogonal group of dimension 10 over GF (2)], HS and Ly.
(2011)The character table of any finite group provides a considerable amount of information about a group and the use of character tables is of great importance in Mathematics and Physical Sciences. Most of the maximal subgroups ... 
Applications of symmetry analysis of partial differential and stochastic differential equations arising from mathematics of finance.
(2011)In the standard modeling of the pricing of options and derivatives as generally understood these days the underlying process is taken to be a Wiener Process or a Levy Process. The stochastic process is modeled as a stochastic ... 
Applications of Lie symmetries to gravitating fluids.
(2011)This thesis is concerned with the application of Lie's group theoretic method to the Einstein field equations in order to find new exact solutions. We analyse the nonlinear partial differential equation which arises ... 
Analysis of shearfree spherically symmetric charged relativistic fluids.
(2011)We study the evolution of shearfree spherically symmetric charged fluids in general relativity. This requires the analysis of the coupled EinsteinMaxwell system of equations. Within this framework, the master field ... 
Initial conditions of the universe : signatures in the cosmic microwave background and baryon acoustic oscillations.
(2012)In this thesis, we investigate the signatures of isocurvature initial conditions in the cosmic microwave background (CMB) through the temperature and polarization anisotropies, and in the largescale structure distribution ... 
On new and improved seminumerical techniques for solving nonlinear fluid flow problems.
(2012)Most real world phenomena is modeled by ordinary and/or partial differential equations. Most of these equations are highly nonlinear and exact solutions are not always possible. Exact solutions always give a good account ... 
Bounds on distancebased topological indices in graphs.
(2012)This thesis details the results of investigations into bounds on some distancebased topological indices. The thesis consists of six chapters. In the first chapter we define the standard graph theory concepts, and ... 
Differential equations for relativistic radiating stars.
(2013)We consider radiating spherical stars in general relativity when they are conformally flat, geodesic with shear, and accelerating, expanding and shearing. We study the junction conditions relating the pressure to the ... 
Exact models of compact stars with equations of state.
(2013)We study exact solutions to the EinsteinMaxwell system of equations and relate them to compact objects. It is well known that there are substantial analytic difficulties in the modelling of selfgravitating, static fluid ...