South African Computer Journal - Volume 2007, Issue 39, 2007
Volumes & issues
Volume 2007, Issue 39, 2007
Source: South African Computer Journal 2007, pp 1 –7 (2007)More Less
Tandem repeats are repeated sequences whose copies are adjacent along the chromosomes. They account for large portion of eukaryotic genomes and are found in all types of living organisms. Among tandem repeats, those with repeat unit of middle size are called minisatellites. These loci depart from classical loci because of the propensity to vary in size due to the addition or the removal of one or more repeat units. Due to this polymorphism, they prove useful in genetic mapping, in population genetics, and forensic medicine. Moreover, some specific tandem repeat loci are involved in diseases, like the insulin minisatellite, which is implicated in type I diabetes and obesity. Those loci also undergo complex recombination events. Presently, some programs to compare tandem repeats alleles exist and yield good results when recombination is absent, but none correctly handles recombinant alleles. Our goal is to develop an adequate tool for the detection of recombinant among a set of minisatellite sequences. By combining a multiple alignment tool and a method based on phylogenetic profiling, we design a first solution, called MS_PhylPro, for this task. The method has been implemented, tested on real data sets from the insulin minisatellite, and proven to detect recombinant alleles.
Author Daniel J.E. ErasmusSource: South African Computer Journal 2007, pp 8 –16 (2007)More Less
A need exists for localisation algorithms in Wireless Sensor Networks (WSNs) that are scalable, energy efficient and able to function in easy to deploy sensor networks. This paper proposes a beaconless Cluster-based Radial Coordinate Establishment (CRCE) positioning algorithm to locate sensor nodes relative to a local coordinate system. The system does not make use of Global Positioning System (GPS) or any other method to provide a-priori positioning information for a set of nodes prior to the CRCE process.
The objective is to reduce energy consumption while providing a scalable coordinate establishment method by focussing on the minimisation of message exchanges in a WSN. This is achieved by implementing a cluster-based network topology and utilising the processing potential of geographically distributed sensor processors together with radial coordinate propagation.
Three other localisation algorithms are investigated and compared to CRCE to identify the one best suited for coordinate establishment in WSNs. The results show a significant decrease in the number of messages that is necessary to establish a network-wide coordinate system successfully, ultimately proving the CRCE method to be more scalable and energy efficient.
Source: South African Computer Journal 2007, pp 17 –24 (2007)More Less
The nature of wireless sensor networks necessitates specific design requirements, of which energy efficiency is paramount. In this paper we present SEER (Simple Energy Efficient Routing), a novel routing protocol for wireless sensor networks intended to optimise network lifetime. SEER uses a flat network structure for scalability and source initiated communication, along with event-driven reporting to reduce the number of message transmissions. Computational efficiency is achieved by using a relatively simple method for routing path selection. Routing decisions are based on the distance to the base station as well as on remaining battery energy levels of nodes on the path towards the base station. SEER minimizes the number of messages that are sent through the network and thus reduces the overall energy consumption. Simulation results show that SEER achieves significant energy savings for a set of specific conditions.
Business analysis in the South African financial services environment : a model of business analysis methodologySource: South African Computer Journal 2007, pp 25 –34 (2007)More Less
Business analysis is regarded as one of the most important issues of systems development because no other part is more difficult to rectify later. However, current requirements analysis methodologies are inadequate because they have phases that are at a too high level and do not map activities, techniques and tools to appropriate phases. The purpose of this paper was to investigate business analysis in the South African financial services environment and to develop a model of business analysis methodology.
This research was based on a qualitative research approach. Sixty participants made up of CIOs, business analysts, project managers and IS managers were interviewed and their experiences with regard to business analysis were investigated through focus group and individual interviews. Participants presented a purposive convenient sample. The researchers of this study performed the data analysis which consisted of finding patterns and themes, deriving categories and sub-categories by means of the constant comparative method.
The most important findings were: the phases of a model of business analysis methodology are the feasibility phase, business case phase, analysis and design phase and the post-implementation evaluation phase. The objectives, outcomes and relevance of each of those phases were also identified. In addition, appropriate activities, techniques and tools were mapped to each of those phases.
Source: South African Computer Journal 2007, pp 35 –46 (2007)More Less
This paper describes a system called Mapster that allows users in a P2P network to share their databases. The research addresses problems of heterogeneity and scalability in P2P databases. To provide fine-grained access to users' databases, schema matching and a super-peer topology are used. The schema matching component allows information to be translated by semi-automatically determining the mappings between the databases within the P2P network. A super-peer topology enables the schema matching techniques to operate effectively in large, dynamic, heterogeneous networks.
Source: South African Computer Journal 2007, pp 47 –53 (2007)More Less
The primary objectives of this study were to identify how IT projects can be managed using the Balanced Scorecard approach. Although the research is positioned to have potential application within international project management discipline, the analysis is limited to a South African project management perspective and only internal aspects of managing projects are considered.
Author Stefan GrunerSource: South African Computer Journal 2007, pp 54 –55 (2007)More Less
In a recent issue of the INNOVATE magazine, we could read the following definition: "Informatics in an interdisciplinary science that explores the application and effect of IT in business, organizations and society. It is regarded as a social science that focuses on the human aspects in the symbiotic relationship between computers and people. Informatics uses methodologies and research paradigms typical of the humanities, such as qualitative research and anti-positivistic points of departure".