https://ir.unisa.ac.za/handle/10500/24279 2026-05-06T12:53:49Z 2026-05-06T12:53:49Z Wagener, M.J. De Kock, G de V https://ir.unisa.ac.za/handle/10500/24298 2018-06-19T10:50:35Z 1988-01-01T00:00:00Z

Rekenaar spraaksintese: die omskakeling van teks na klank - 'n prestasiemeting Wagener, M.J.; De Kock, G de V Verslag word gelewer oor 'n prestasiemeting van 'n stel letter-na-klank reels vir die omskakeling van Afrikaanse teks na foneme. Die prestasie van die stel reels word getoets deur gebruik te maak van 'n verteenwoordigende steekproef van 1 427 Afrikaanse woorde. Verskeie statistieke wat die sukses, al dan nie, van die stel reels weerspieel, word verskaf en bespreek.

1988-01-01T00:00:00Z Rennhackkamp, M.H. Von Solms, S.H. https://ir.unisa.ac.za/handle/10500/24297 2018-06-07T01:01:09Z 1988-01-01T00:00:00Z

Modelling distributed database concurrency control overheads Rennhackkamp, M.H.; Von Solms, S.H. Numerous concurrency control methods have been proposed for distributed databases. Various crz·teria are used to compare these methods. The comparisons range from qualitative overviews through quantitative analyses to theoretical studies. A quantitative study based on an abstract model of concurrency control methods is presented, where the overheads of the methods are analytically compared using a set of evaluation parameters. After an overview of the model's development, lt is presented Zn detail. As an example it is applied to two-phase locking as can be used in a fully-redundant distributed environment. It is concluded that although the model h,as shortcomings, it does provide a framework according to whfrh distributed database concurrency controls can be comp11red.

1988-01-01T00:00:00Z Postma, Stef W. https://ir.unisa.ac.za/handle/10500/24292 2018-06-07T01:00:38Z 1988-01-01T00:00:00Z

Traversable trees and forests Postma, Stef W. Two topics are studied, related and generalised in this paper - the Knuth transform of an arbitrary tree to a binary tree, and Pfaltz' s definition of a data structure as a graph with assignments. Trees are defined in terms of undirected graphs, and the binary tree is shown to be a data structure. And/or graphs are considered and generalised to fans which are shown to be Knuth transformable. A (presumably most) general structure which is Knuth transformable is then defined, a possible notation is suggested, and its implementation in Octolisp is indicated.

1988-01-01T00:00:00Z Orlowska, M.E. https://ir.unisa.ac.za/handle/10500/24290 2018-06-07T01:01:14Z 1988-01-01T00:00:00Z

On syntax and semantics related to incomplete information databases Orlowska, M.E. We propose a mathematical model of a database with incomplete information, which we call the N-system. Basically speaking, such a system stores information concerning properties of some objects. The information may be incomplete in that it may be known that the object has a property with probability from the interval <a,[3> c <0,1>. In the particular case where <a,[3>=<0,1>, means that it may be not known whether an object has a property, the N-system is equivalent to Lipski' s system [3]. In another particular case, when <a,[3>=<1,1> or <a,{3>=<0,0> the N-system presented corresponds to Codd' s relational model of databases []]. The first level, the level of terms of a query language to communicate with the N-system, is described and its semantics and syntax are defined. A system of axioms, which serves as a basis/or equivalent transformations of queries is presented ( only for terms). Syntactical and semantic equivalences for terms are defined and completeness properties are shown.

1988-01-01T00:00:00Z