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Case-Based Reasoning is a fairly new Artificial Intelligence technique which makes use of past experience as the basis for solving new problems. Typically, a case-based reasoning system stores actual past problems and solutions in memory as cases. Due to its ability to reason from actual experience and to save solved problems and thus learn automatically, case-based reasoning has been found to be applicable to domains for which techniques such as rule-based reasoning have traditionally not been well-suited, such as experience-rich, unstructured domains. This applicability has led to it becoming a viable new artificial intelligence topic from both a research and application perspective. This dissertation concentrates on researching and implementing indexing techniques for casebased reasoning. Case representation is researched as a requirement for implementation of indexing techniques, and pre-transportation decision making for hazardous waste handling is used as the domain for applying and testing the techniques. The field of case-based reasoning was covered in general. Case representation and indexing were researched in detail. A single case representation scheme was designed and implemented. Five indexing techniques were designed, implemented and tested. Their effectiveness is assessed in relation to each other, to other reasoners and implications for their use as the basis for a case-based reasoning intelligent decision support system for pre-transportation decision making for hazardous waste handling are briefly assessed. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.

Three experiments were conducted to investigate the hypothesis that young infants? failures to search for occluded objects arises, not from deficiencies in their object representations, but from limitations in experience with the physical world. Successful means-end search is typically found at 8 months of age and is traditionally taken as the hallmark of object permanence. However, recent evidence suggests that infants much younger than 8 months of age are able to represent and reason about objects that are no longer visible. In Experiment 1, successful means-end search was found for 8. 5-, but not 6. 5-month-old infants in a traditional task, but younger infants showed successful search ability when the task was made familiar to them in Experiment 2 (i. e. , when the toy and occluder are first presented as a single composite object), and when they were given the opportunity to watch a demonstration of the solution to the task in Experiment 3. These results are taken as evidence for the ?experiential limitation? hypothesis and suggest that young infants are more apt at solving manual search tasks than previously acknowledged.

Reasoning from all knowledge and belief is an adaptive approach to thinking about the world. It has been robustly shown that conditional ‘if then’ reasoning with everyday content is influenced by the background knowledge an individual has available. If we are presented with the statement ‘if it rains, then John will get wet’ then we are told that it is raining and asked if John will get wet, we may consider a number of possibilities before answering the question; perhaps John has an umbrella or is sheltered from the rain. Hence, when engaged in conditional reasoning of this sort people typically draw on background knowledge to arrive at an informed response. People with autism tend not to process information in context. There is a wealth of evidence indicating that these individuals have a piecemeal rather than an integrative processing style. It was therefore hypothesised that adolescents with autism spectrum disorder (ASD) would be less influenced by background knowledge when engaged in conditional reasoning with everyday content. Adolescents with ASD showed a weak or absent effect of available background knowledge on reasoning outcomes compared to a typically developing control group. This finding was demonstrated in two separate conditional reasoning tasks. These results were not explained by a failure to generate background knowledge or by differences in the beliefs held by the two groups regarding problem content. Within the typical population a lack of contextualised reasoning was also found among participants with high scores on one particular autistic trait, attention to detail. The ability to integrate all relevant information during conditional reasoning was also found to be dependent on available working memory resources. These results extend the known domains which demonstrate a lack of contextualised processing in autism. They also show that for individuals with autism reasoning without regard for background knowledge stems from a failure to integrate information. The findings suggest that this failure is related to the cognitive demands of the task and the processing style of the individual.

No description available.

Collective phenomena are ubiquitous in our every day lives; each day we are likely to observe or take part in a collective. Examples include a traffic jam on the way to work, a flock of birds in the sky or a queue in the shop. These examples include only three types of collective that are considered in this thesis: those phenomena whose individual members can be assigned a physical location in geographic space. However, this criterion is satisfied by many different types of collective. The movement patterns that are exhibited by collectives are one of their most prominent properties; it is often the property that we wish to reason about most. For example, the movement patterns of crowds, traffic or demonstrations. This thesis hypothesises that, given a dataset that comprises the movement data for a group of individuals, the presence of certain collectives can be achieved through an examination of the exhibited movement patterns. To identify the different types of collective that exist, a general taxonomy of collectives is presented. A class of collectives are found to manifest themselves through spatial coherence. Therefore, a set of spatial coherence criteria have been developed that can be applied to a movement dataset to indicate if any individuals within that dataset may be participating in a spatial collective. To indicate the different types of spatial collective that may be extracted, a taxonomy of spatial collectives is also presented.

Student Number : 0001241N - M Industrial Psychology dissertation - School of Human and Community Development - Faculty of Humanities / The following thesis explores the variables of math anxiety, deductive reasoning and career appraisal. This dissertation investigates whether there is a relationship between math anxiety and deductive reasoning. A relationship is found to exist between these two variables and the relationship is of an indirectly proportional nature. As a result, when “math anxiety is high, deductive reasoning is low” and visa viz. 74 participants were used in this research study to assess whether their appraisal of various careers differed or were homogenous in nature. This thesis discusses how various careers were appraised heterogeneously and others homogenously between people with different levels of math anxiety and deductive reasoning. This phenomenon is also explained through the possibility of extraneous factors, influencing these results.

This study has examined how the attainment of theoretical frameworks may create the conditions for and support subsequent learning of related material. In this regard, it has investigated a particular conception of Vygotsky‟s proposal that learning only occurs in the zone of proximal development, which he defined as the gap between what can be performed independently and what can be achieved with assistance. Specifically, it used a multi-pronged, mixed method research approach to probe the relationship between the actual level of development, as reflected by an ability to do proportional reasoning, and potential development, which was measured as the ability to perform certain strategic procedural operations in the molecular biosciences which were underpinned by proportionality. This four phase study which was carried out on a class of 106 second year students registered for Basic Molecular Biosciences II in the School of Molecular and Cell Biology, at the University of the Witwatersrand, Johannesburg, South Africa, initially measured proportional reasoning ability by posing a generative question requiring proportional reasoning to the class during a lecture and established that only 49% of the students who participated were able to answer the question. It could be shown statistically that these students were more adept at answering a contextual question based on proportion than those who had answered the generative question incorrectly, which suggested that actual development created the conditions for future learning. A paper and pencil test developed from Fleener (1993) which claimed to measure the hierarchical development of proportional reasoning ability was administered to the class and was used to select two groups for comparative purposes. The first group (group one) was comprised of the 23 students who scored 50 % or less, and the control group (group two) consisted of the 15 students who scored 100 %. Using these two groups, it was shown that the control group performed better than group one on specific questions underpinned by proportion which had been included in pre-laboratory tests and in summative assessments. Moreover, the control group‟s general performance in the course, as assessed by their marks in the examination at the end of the first semester, was substantially better than that of group one (67 % as opposed to a 51% average mark). These results were supported by findings where conceptual development of proportion had been judged from student‟s informal written accounts of the concept. Drawing on biological evidence, it was concluded that the actual level produces the structures necessary for further development. The second phase of the study utilized two focus groups constituted from students who iv had been randomly selected from the two groups compared in phase one of the research. Facilitated guided informal discussions probed which of factors like play and leisure activities, early childhood enrichment, schooling, mathematical ability and practices, instruction in proportional reasoning, and parental involvement, might have augmented the development of proportional reasoning ability. In phase three, the factors which emerged from the discussions were interrogated in a specially designed questionnaire which was administered to a sub-set of students who were concurrently registered for Basic Molecular Biosciences II and Biochemistry and Cell Biology II. Statistical analysis of the questionnaire which occurred in phase four of the research led to the conclusion that enrichment in early childhood, and having learnt proportion at school were the two factors that contributed most to attainment of the actual level of development which would enable subsequent learning of more elaborate procedural knowledge constructs based on the concept of proportion. These results supported the view that mediation results in internalisation of the embedded knowledge which can be drawn on for further learning in that domain. Therefore, in the final analysis of the research, it was concluded that actual levels of development create conditions for potential development as conceived by Vygotsky‟s zone of proximal development.

faculty of Humanities School of Human and Community Development 9807986h IsrealN@umthombo.wits.ac.za / The issue of bias, whether a psychological test measures what it claims to measure similarly across different groups, remains a fundamental concern within the field of psychometrics, particularly within South Africa, where a history riddled with oppression, discrimination and malpractice in the area has led to suspicion, mistrust and legislation banning the use of many psychological tests as invalid and unfair (Foxcroft & Roodt, 2001; Murphy & Davidshofer, 2001; Nell, 1999). There is thus clearly a need for additional and more detailed investigations of the way specific individual tests function in the South African context. This study attempted to creatively examine systematic differences in performance on one specific test, the Raven’s Advanced Progressive Matrices (RAPM), on the basis of home language and gender, factors seldom investigated in the literature. A sample of one hundred Psychology first-year students completed a demographic questionnaire, the RAPM, the Similarities sub-test of the South African Wechsler Adult Intelligence Scales (SAWAIS) and an adapted version of the Reading Comprehension subtest of the Stanford Diagnostic Reading Test (SDRT). The data gathered was then utilized to explore four main research questions. Firstly, in order to establish construct comparability, the relationship between the RAPM and a more verbally-oriented measure of g, the Similarities sub-test of the SAWAIS, was assessed. Results indicated a relatively strong positive relationship between the two measures (r = 0.66), and no significant differences between the correlations on the basis of either gender or home language. Secondly, in order to explore the relationship between the RAPM and English comprehension, the study assessed the relationship between overall, literal and inferential scores on an adapted version of the Reading Comprehension sub-test of the SDRT and the RAPM. Results indicated only a moderate relationship between the two tests (r = 0.65), no difference in the relationship between RAPM performance and literal comprehension or inferential comprehension, and no difference in the relationship between the two tests on the basis of either gender or home language. Thirdly, in order to establish whether items were found to be difficult in a similar way across the different gender and home language groups, p-values and regression lines were calculated. These indicated that significant differences in level of item difficulty were experienced between English and African language speakers, although no differences were apparent in item difficulty on the basis of gender. 5 Lastly, in order to establish whether qualitative differences in performance on the basis of ability (as estimated by performance on the RAPM), gender or language existed, a discrimination analysis examining the types of errors made by each group was performed. Repeated measures ANOVAs and multiple comparison post-hoc analyses revealed significant differences in the types of errors made on the basis of ability and home language, but not gender. The post-hoc analyses suggested that those of higher ability or first language English speakers were more likely to make incomplete correlate errors, while those of lower ability or speaking African first languages were more likely to make confluence of ideas errors. In general, the findings of the study seemed to suggest that the RAPM, while not biased on the basis of gender, might contain a deep-seated language bias despite their non-verbal presentation.

This study aims to explore GET learners’ mathematical (algebraic) reasoning when generalizing from number patterns. Data was collected in a former model C school in greater Johannesburg area by means of a questionnaire based task involving number patterns. The mathematical reasoning of the grade 9 participants when generalizing from number patterns was examined within a commognitive framework. According to this perspective, thinking is a special activity of communication in which a participant of a discourse engages. The participants’ responses to questions in the questionnaire based task were classified according to particular aspects of the discourse they used, specifically routines (strategies) and visual mediators. The participants’ generalization routines were further classified into one of the three main categories; numeric, figural and pragmatic generalizations. The analysis focused on how the learners’ derived rules for the nth term and their justifications for their responses. The results of this study strongly support the notion that students’ algebraic reasoning when generalizing in number patterns is intertwined with their choices of routines and mediators. Most learners used recursive routines while a few used explicit routines (classified and categorized as numeric routines) and number-mediators. Also, most participants found it easier to informally verbalize their generalizations. However participants’ spoken justifications of their written and spoken responses often did not match their use of routines and visual mediators. As such, an awareness and appreciation (by teachers) of students’ diverse use of routines and mediators when generalizing from number patterns could have direct pedagogical implications in the mathematics classrooms.