AFRICA RESEARCH JOURNAL VOLUME 105 No3
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1. Landmine Detection by Means of Ground Penetrating Radar: A Model Based Approach
2. The Influence of major Internal and External Events on the Culture of an Engineering Organisation
3. A South African Perspective of the Requirements Discipline: An Industry Overview
4. Rotation Hough Transform
LANDMINE DETECTION BY MEANS OF GROUND PENETRATING RADAR: A MODEL BASED APPROACH
by P. A. van Vuuren
Abstract: The presence of landmines poses a worldwide humanitarian problem. Often, these mines are difficult to detect with metal detectors. Ground penetrating radar (GPR) is a promising technology for the detection of landmines with low metal content. Automatic landmine detection typically consists of two steps, namely preprocessing (or clutter removal) and classification. In this paper the clutter removal algorithm consists of a nonlinear frequency domain filter followed by principal component based filtering. Principal component analysis is performed in the frequency domain to build a background model for the clutter. The latter model is removed from the observed data in the log-frequency domain in order to preserve the phase component of the spectrum. Finally, the data is normalized and transformed to the time domain. The results presented in this paper show a marked improvement in the ability to remove general background clutter. Classification is performed on the basis of the prediction performance of neural network time-series models of the various classes of GPR responses. The classification system can correctly identify the position of metal anti-tank (AT) mines. It can also recognize specific examples of low metal AT and (anti-personnel) AP mines, but does have a low generalization ability for such mines.
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THE INFLUENCE OF MAJOR INTERNAL AND EXTERNAL EVENTS ON THE CULTURE OF AN ENGINEERING ORGANISATION
A SOUTH AFRICAN PERSPECTIVE OF THE REQUIREMENTS DISCIPLINE: AN INDUSTRY OVERVIEW
by W. Theron, L. Pretorius and K-Y. Chang
Abstract: A Case study company that was set up as a project where the technical focus, activities and behaviour set the initial culture is considered in this research. Over a period of 11 years the Case study engineering organisation was exposed to many influences in the electrical utility industry that now give lead to questions such as: How did events influence the engineering culture and how did the culture change over time? Engineering organisations are subjected to external and internal events which are not always within their control. These include technological changes, economical changes or new competition, change in ownership, business focus or technical leadership. The ability to absorb such events is not only a function of the organisation’s technology infrastructure, availability of funding or skills, but also of the organisational culture prevailing at the time. The objective of the research is to determine how eight events impacted the culture of an engineering organisation over a period of six years. The results show that the culture is indeed influenced by events, with an indication that the different work areas within the organisation experienced the cultural changes
differently. The employees that worked for the organisation six years or longer also experienced the changes differently from those that were only employed for the last five years of the organisation’s life. These results may assist the understanding of the impact that events may have on an organisation and allow early risk mitigation to counter undesirable culture forming.
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by A Marnewick, JHC Pretorius and L Pretorius
Abstract: The requirements discipline is at the heart of systems engineering, software engineering and business analysis. Across these three communities common practices, approaches and techniques are available in literature. However, little application data is available on how practitioners apply these common practices during the requirements engineering process in practise. To generate data on how practise carries out the requirements engineering process, a two-part survey was conducted. The first part of the survey is reported here and investigates how practitioners carry out the requirements engineering process. The survey was completed by individuals involved in practice as requirements practitioners. This survey and its results offer opportunities to increase industry relevance of research outcomes and identified focus areas for practitioners, including software system developers, to exploit and increase their effectiveness during requirements activities.
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ROTATION HOUGH TRANSFORM
Abstract: This article discusses how image space discretization errors affect the standard Hough transform (SHT). It is observed that the discretization errors are different on various columns, that is, they are related to the θ values. Furthermore, the columns corresponding to θ=0o and θ=90o are seen to have the smallest errors. Based on this observation, a new Hough transform (rotation Hough transform, RoHT) is proposed. The given image is rotated by Δθ and the SHT is employed, generating the HT data on the columns corresponding to θ=0o and θ=90o only. After the image is rotated 90o/Δθ times, the HT columns generated are registered to the HT matrix of the original image. In this way, only θ=0o and θ=90o are used to calculate the votes for each cell in HT space, and theerrors are minimized. The experiments verified the performance of the proposed method.
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