Quaestiones Informaticae Vol 6 No 2https://hdl.handle.net/10500/242792024-03-28T18:34:08Z2024-03-28T18:34:08ZRekenaar spraaksintese: die omskakeling van teks na klank - 'n prestasiemetingWagener, M.J.De Kock, G de Vhttps://hdl.handle.net/10500/242982018-06-19T10:50:35Z1988-01-01T00:00:00ZRekenaar 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.
1988-01-01T00:00:00ZModelling distributed database concurrency control overheadsRennhackkamp, M.H.Von Solms, S.H.https://hdl.handle.net/10500/242972018-06-07T01:01:09Z1988-01-01T00:00:00ZModelling 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.
1988-01-01T00:00:00ZTraversable trees and forestsPostma, Stef W.https://hdl.handle.net/10500/242922018-06-07T01:00:38Z1988-01-01T00:00:00ZTraversable 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.
1988-01-01T00:00:00ZOn syntax and semantics related to incomplete information databasesOrlowska, M.E.https://hdl.handle.net/10500/242902018-06-07T01:01:14Z1988-01-01T00:00:00ZOn 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