Browsing by Author "Marais, Laurette"

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    Generalised acceptance conditions for symmetric difference nondeterministic finite automata
    (Stellenbosch : Stellenbosch University, 2018-03) Marais, Laurette; Van Zijl, Lynette; Stellenbosch University. Faculty of Science. Dept. of Mathematical Sciences (Computer Science)
    ENGLISH ABSTRACT : Symmetric difference nondeterministic finite state automata (XNFA) are an instance of generalised nondeterminism, of which the behaviour is represented by the symmetric difference of all possible computation paths. We introduce the notion of generalised acceptance for XNFA, and investigate descriptional complexity issues related to two specific instances, namely self-verifying XNFA (SV-XNFA) and *- XNFA. For SV-XNFA, we apply self-verifying acceptance, originally defined for typical nondeterministic finite state automata (NFA), to XNFA. Self-verification involves defining a set of accept states, as well as a set of reject states, and requires that the automaton give an explicit accept or reject result on any input. We provide state complexity bounds for determinising unary and non-unary SV-XNFA. We define *-XNFA as XNFA with any finite number of final sets, while * represents a left-associative set operation on the language associated with each set of final states. We investigate and compare the descriptional complexity of various language operations, namely intersection, union, relative complement (or difference), symmetric difference and complement, for unary XNFA and unary *-XNFA.
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    Learning new words from an interactive electronic storybook intervention
    (AOSIS, 2018) Klop, Daleen; Marais, Laurette; Msindwana, Amanda; De Wet, Febe
    Background: Children who enter school with limited vocabulary knowledge are at risk for reading failure. This study investigated the efficacy of an interactive e-book, implemented as a mobile application, to facilitate vocabulary learning in Grade 1 isiXhosa-speaking children (n = 65). Objective: The purpose was to measure if an e-book intervention, specifically developed for use in the South African context, could facilitate the acquisition and retention of new words at different levels of lexical representation. Method: A randomised pre-test and/or post-test between-subject design was used where an experimental group that received the e-book intervention was compared to a control group before the control group received a delayed intervention. Follow-up testing was performed to measure retention of the new vocabulary after eight weeks. Mixed-model repeated-measure Analysis of Variance (ANOVAs) were used to determine differences between the participants in the experimental and control groups. Results: The short-term e-book intervention not only facilitated fast-mapping of new words but enabled participants to develop more robust lexical representations of the newly acquired words. Follow-up assessment showed that they retained their newly acquired word knowledge. Conclusion: Multimedia technology can be used to provide explicit and embedded vocabulary training to young children at risk for academic failure. These findings are particularly relevant for South African environments where there is limited parental support and lack of educational resources to promote vocabulary learning in young children.