Now showing items 1-20 of 69

    • Some Mal'cev conditions for varieties of algebras. 

      Moses, Mogambery. (1991)
      This dissertation deals with the classification of varieties according to their Mal'cev properties. In general the so called Mal'cev-type theorems illustrate an interplay between first order properties of a given class ...
    • Conformal symmetries : solutions in two classes of cosmological models. 

      Moodley, Manikam. (1991)
      In this thesis we study the conformal symmetries in two locally rotationally symmetric spacetimes and the homothetic symmetries of a Bianchi I spacetime. The conformal Killing equation in a class AIa spacetime (MacCallum ...
    • Partial exchangeability and related topics. 

      North, Delia Elizabeth. (1991)
      Partial exchangeability is the fundamental building block in the subjective approach to the probability of multi-type sequences which replaces the independence concept of the objective theory. The aim of this thesis is ...
    • Conformal motions in Bianchi I spacetime. 

      Lortan, Darren Brendan. (1992)
      In this thesis we study the physical properties of the manifold in general relativity that admits a conformal motion. The results obtained are general as the metric tensor field is not specified. We obtain the Lie derivative ...
    • The theory of option valuation. 

      Sewambar, Soraya. (1992)
      Although options have been traded for many centuries, it has remained a relatively thinly traded financial instrument. Paradoxically, the theory of option pricing has been studied extensively. This is due to the fact ...
    • On Stephani universes. 

      Moopanar, Selvandren. (1992)
      In this dissertation we study conformal symmetries in the Stephani universe which is a generalisation of the Robertson-Walker models. The kinematics and dynamics of the Stephani universe are discussed. The conformal ...
    • Relativistic spherical stars. 

      Mkhwanazi, Wiseman Thokozani. (1993)
      In this thesis we study spherically symmetric spacetimes which are static with a perfect fluid source. The Einstein field equations, in a number of equivalent forms, are derived in detail. The physical properties of a ...
    • On the integrity of domination in graphs. 

      Smithdorf, Vivienne. (1993)
      This thesis deals with an investigation of the integrity of domination in a.graph, i.e., the extent to which domination properties of a graph are preserved if the graph is altered by the deletion of vertices or edges or ...
    • Aspects of graph vulnerability. 

      Day, David Peter. (1994)
      This dissertation details the results of an investigation into, primarily, three aspects of graph vulnerability namely, l-connectivity, Steiner Distance hereditatiness and functional isolation. Following the introduction ...
    • Distance measures in graphs and subgraphs. 

      Swart, Christine Scott. (1996)
      In this thesis we investigate how the modification of a graph affects various distance measures. The questions considered arise in the study of how the efficiency of communications networks is affected by the loss of ...
    • 2-generations pf the sporadic simple groups. 

      Ganief, Moegamad Shahiem. (1997)
      A group G is said to be 2-generated if G = (x, y), for some non-trivial elements x, y E G. In this thesis we investigate three special types of 2-generations of the sporadic simple groups. A group G is a (l, rn, n )-generated ...
    • A modelling approach for determining the freshwater requirements of estuarine macrophytes. 

      Wortmann, Joanne. (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 ...
    • Developing an integrated decision support system for an oil refinery. 

      Azizi, Abbas. (1998)
      This thesis considers the problem of residue upgrading operations in an oil refinery. Visbreaking is a residue-upgrading process that improves profitability of a refinery. The economics of converting the heavy residue ...
    • Spatial modelling of fire dynamics in Savanna ecosystems. 

      Berjak, Stephen Gary. (1999)
      Fire is used in the management of ecosystems worldwide because it is a relatively inexpensive means of manipulating thousands of hectares of vegetation. Deciding how, where and when to apply fire depends primarily on the ...
    • Interative approaches to convex feasibility problems. 

      Pillay, Paranjothi. (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 ...
    • Assessment of variability in on-farm trials : a Uganda case. 

      Lapaka, Odong Thomas (2002)
      On-farm trials techniques have become an integral part of research aimed at improving agricultural production especially in subsistence farming. The poor performance of certain technologies on the farmers' fields known to ...
    • Application of the wavelet transform for sparse matrix systems and PDEs. 

      Karambal, Issa. (2009)
      We consider the application of the wavelet transform for solving sparse matrix systems and partial differential equations. The first part is devoted to the theory and algorithms of wavelets. The second part is concerned ...
    • Wadley's problem with overdispersion. 

      Leask, Kerry Leigh. (2009)
      Wadley’s problem frequently emerges in dosage-mortality 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, ...
    • Bayesian analysis of cosmological models. 

      Moodley, Darell. (2010)
      In this thesis, we utilise the framework of Bayesian statistics to discriminate between models of the cosmological mass function. We first review the cosmological model and the formation and distribution of galaxy clusters ...
    • Group analysis of equations arising in embedding theory. 

      Okelola, Michael. (2010)
      Embedding theories are concerned with the embedding of a lower dimensional manifold (dim = n, say) into a higher dimensional one (usually dim = n+1, but not necessarily so). We are concerned with the particular case of ...