http://hdl.handle.net/10204/453 2013-05-22T16:52:03Z http://hdl.handle.net/10204/6742 Title: Environmental change in Bushbuckridge Authors: Erasmus, BFN; Coetzer, K; Mambo, J; Archer, E; Fisher, JT; Asner, GP Abstract: Bushbuck Ridge is a typical cultural landscape where the interdependency of people and the environment shape the savanna ecosystem goods and services upon which many people are dependent. The forced resettlement of people in the apartheid era, together with Mozambican refugees, have resulted in high human densities. The majority of people rely heavily on the rural rangelands for a variety of natural products, and the ability of these ecosystems to continue delivering these products under conditions of climate change and land cover change is in doubt. Historical trends show that settlements are expanding, with an increasing corresponding footprint around each village, where woodland resources are depleted. People can and do adapt to environmental change, but projecting current trends in the changes that we observe, combined with increased unpredictability of rainfall, threatens to decouple the age-old interdependencies in the this cultural landscape, and present inhabitants with conditions beyond their adaptation capacity. Description: Copyiright: Sun Media Publishing,Stellenbosch, South Africa 2011-05-01T00:00:00Z http://hdl.handle.net/10204/6736 Title: The velocity of the expanding by-products and soil layer on top of a buried landmine Authors: Snyman, I.M Abstract: This paper uses high-speed video images of the PHOTRON APX-RS high-speed camera to determine the velocity of the expanding volume of by-products of a buried landmine. The study analyses three experiments done with the Scientifically Instrumented Impulse Measurement Apparatus (SIIMA) to determine the imparted impulse of a landmine. Two phenomena emerge from the analyses. The expansion of the flush buried mine is very fast while the expansion of the sand layer and volume of by-products when the charge is buried with an overburden is slower. Description: 30th International Congress on High-Speed Imaging & Photonics, CSIR ICC,Pretoria, South Africa, 16 - 21 September 2012. 2012-09-01T00:00:00Z http://hdl.handle.net/10204/6733 Title: Quality measures for HRR alignment based ISAR imaging algorithms Authors: Janse van Rensburg, V; Mishra, A; Nel, W Abstract: Some Inverse Synthetic Aperture Radar (ISAR) algorithms form the image in a two-step process of range alignment and phase conjugation. This paper discusses a comprehensive set of measures used to quantify the quality of range alignment, with the aim of 1) reviewing their benefits and shortcomings and 2) comparing their relative performance. Some quality measures may favour particular alignment techniques without adequately indicating improved alignment, so using multiple quality measures provide an added means of verifying the alignment quality achieved by any alignment technique. The sensitivity of the quality measures to slight misalignment of profiles and the effects of noise is also investigated. Description: IEEE Radar Conference 2013, Ottawa Canada, 29 April - 3 May 2013 2013-05-01T00:00:00Z http://hdl.handle.net/10204/6713 Title: Insights into factors contributing to the observability of a submarine at periscope depth by modern radar, Part 2: EM simulation of mast RCS in a realistic sea surface environment Authors: Smit, JC; Cilliers, JE Abstract: Recently, a set of high resolution radar measurements were undertaken in South Africa to gain insight into factors influencing the detectability of submarine masts deployed under realistic operational conditions. The measurements, processing results and some insights gained are described in. The current paper presents the results of a subsequent computational electromagnetic (CEM) simulation investigation of a simplified mast model in a realistic sea surface environment. The results illustrate some of the effects of the sea surface reflection interaction on the observed RCS of a submarine mast. Description: 2012 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), Cape Town 2-7 September 2012 2012-09-01T00:00:00Z