South African Computer Journal - Volume 2007, Issue 38, 2007
Volumes & issues
Volume 2007, Issue 38, 2007
Source: South African Computer Journal 2007, pp 2 –7 (2007)More Less
By its very nature education aims to change learners' knowledge and this inevitably has an impact on the learners' world views. This paper explores the dilemmas facing Information Systems (IS) educators with respect to their role in the process of changing learners' conceptual views of IS. IS as an academic discipline has moved from a 'technical' to a 'socio-technical' domain, but IS practitioners still work in an IS field dominated by a 'technical' world view. Curricula at undergraduate levels reinforce this 'technical' standpoint. However, the contemporary debates in IS literature and the 'socio-technical' divide facing South Africa suggest the need to adopt a more 'socio-technical' approach to IS teaching. Such an approach is adopted, if at all, only at postgraduate level. This raises the question for us as educators regarding the future role for which we educate our IS learners: technical expert; enactor of shared meaning (facilitator), or moral agent for emancipation.
Generalizations from an interpretive study : the case of a South African community-based health information system : reviewed articleSource: South African Computer Journal 2007, pp 8 –19 (2007)More Less
This paper explores the making of generalizations from interpretive research by examining the process of developing a community-based information system (IS) in a rural area in South Africa. Lee and Baskerville's framework of four categories, and Walsham's four types, of generalizations form a framework that is used in this case study. Using the concept of the Ideal Speech Situation two empirical to theoretical generalizations are made: the reconceptualization of participation and the need to generate common ground in which free and open dialogue between those who use, and those who are affected by the IS, is made possible. The main argument of this paper, using the generalizations made from this single case study, is that generalizations from interpretive research can be made and that much valuable contribution in the IS field is lost because IS researchers fail to make these generalizations.
Source: South African Computer Journal 2007, pp 20 –27 (2007)More Less
Genetic recombination can produce heterogeneous phylogenetic histories within a set of homologous genes. Delineating recombination events is important in the study of molecular evolution, as inference of such events provides a clearer picture of the phylogenetic relationships among different gene sequences or genomes. Nevertheless, detecting recombination events can be a daunting task, as the performance of different recombination-detecting approaches can vary, depending on evolutionary events that take place after recombination. We previously evaluated the effects of post-recombination events on the prediction accuracy of recombination-detecting approaches using simulated nucleotide sequence data. The main conclusion, supported by other studies, is that one should not depend on a single method when searching for recombination events. In this paper, we introduce a two-phase strategy, applying three statistical measures to detect the occurrence of recombination events, and a Bayesian phylogenetic approach to delineate breakpoints of such events in nucleotide sequences. We evaluate the performance of these approaches using simulated data, and demonstrate the applicability of this strategy to empirical data. The two-phase strategy proves to be time-efficient when applied to large datasets, and yields high-confidence results.
Source: South African Computer Journal 2007, pp 28 –39 (2007)More Less
Although the complexity of prosody is widely recognised, the lack of widely-accepted descriptive standards for prosodic phenomena has meant that prosodic systems for most of the languages of the world have, at best, been described in impressionistic rule-based terms. For the languages of Southern Africa, the deficiencies in our modelling capabilities are acute. Little work of a quantitative nature has been published for the languages of the Nguni family (such as isiZulu and isiXhosa), and there are significant contradictions and imprecisions in the literature on this topic, which partially stems from the lack of quantitative, measurement-driven analysis. This paper therefore embarks on a programme aimed at understanding the relationship between linguistic and physical variables of a prosodic nature in this family of languages.
Source: South African Computer Journal 2007, pp 40 –50 (2007)More Less
This paper presents a method to compress irregularly sampled height-fields based on a multi-resolution framework. Unlike many other height-field compression techniques, no resampling is required so the original height-field data is recovered (less quantization error). The method decomposes the compression task into two complementary phases: an in-plane compression scheme for (x, y) coordinate positions, and a separate multi-resolution z compression step. This decoupling allows subsequent improvements in either phase to be seamlessly integrated and also allows for independent control of bit-rates in the decoupled dimensions, should this be desired. Results are presented for a number of height-field sample sets quantized to 12 bits for each of x and y, and 10 bits for z. Total lossless encoded data sizes range from 11 to 24 bits per point, with z bit-rates lying in the range 2.9 to 8.1 bits per z coordinate. Lossy z bit-rates (we do not lossily encode x and y) lie in the range 0.7 to 5.9 bits per z coordinate, with a worst-case root-mean-squared (RMS) error of less than 1.7% of the z range. Even with aggressive lossy encoding, at least 40% of the point samples are perfectly reconstructed.
Author P.K.J. TobinSource: South African Computer Journal 2007, pp 51 –61 (2007)More Less
This article explores the use of storytelling as part of an overall approach to the teaching of information technology in tertiary education. The author defines the context of use of storytelling in terms of the various types of education being delivered and the delivery methods, and then explores the potential uses and benefits of storytelling. A sample story is included and briefly analysed to illustrate how a story might be used; the author also reports on his own experiences of the use of storytelling in his teaching activities. Finally, a detailed checklist is presented of the issues to be considered when using the storytelling approach.
Author Stefan GrunerSource: South African Computer Journal 2007, pp 62 –63 (2007)More Less
For the sake of clarification I should mention that by "Informatics" I mean Computer Science and Computing Science in the widest sense. Being a continental-European Informatician myself I naturally use the term in its continental-European notion - French: informatique; German: Informatik; Dutch, Italian, Spanish: informatica- with its classically four subject categories of Theoretical Informatics (example: Automata Theory), Practical Informatics (example: Databases), Technical Informatics (example: Hardware Architecture), and Applied Informatics (example: Medical Image Processing).