Modelling parallel and distributed virtual reality systems for performance analysis and comparison
- Authors: Bangay, Shaun Douglas
- Date: 1997
- Subjects: Virtual reality Computer simulation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4657 , http://hdl.handle.net/10962/d1006656
- Description: Most Virtual Reality systems employ some form of parallel processing, making use of multiple processors which are often distributed over large areas geographically, and which communicate via various forms of message passing. The approaches to parallel decomposition differ for each system, as do the performance implications of each approach. Previous comparisons have only identified and categorized the different approaches. None have examined the performance issues involved in the different parallel decompositions. Performance measurement for a Virtual Reality system differs from that of other parallel systems in that some measure of the delays involved with the interaction of the separate components is required, in addition to the measure of the throughput of the system. Existing performance analysis approaches are typically not well suited to providing both these measures. This thesis describes the development of a performance analysis technique that is able to provide measures of both interaction latency and cycle time for a model of a Virtual Reality system. This technique allows performance measures to be generated as symbolic expressions describing the relationships between the delays in the model. It automatically generates constraint regions, specifying the values of the system parameters for which performance characteristics change. The performance analysis technique shows strong agreement with values measured from implementation of three common decomposition strategies on two message passing architectures. The technique is successfully applied to a range of parallel decomposition strategies found in Parallel and Distributed Virtual Reality systems. For each system, the primary decomposition techniques are isolated and analysed to determine their performance characteristics. This analysis allows a comparison of the various decomposition techniques, and in many cases reveals trends in their behaviour that would have gone unnoticed with alternative analysis techniques. The work described in this thesis supports the Performance Analysis and Comparison of Parallel and Distributed Virtual Reality systems. In addition it acts as a reference, describing the performance characteristics of decomposition strategies used in Virtual Reality systems.
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- Date Issued: 1997
Ndemka
- Authors: Group performance , Group composition , Dargie, Dave
- Date: 1997
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Hogsback sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/343555 , vital:63023 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC346b-02
- Description: Church music
- Full Text: false
- Date Issued: 1997
Ndinothixo omkhulu
- Authors: Performer not specified , Composer not specified , Dargie, Dave
- Date: 1997
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Hogsback sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/343091 , vital:62968 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC343a-09
- Description: Traditional xhosa music accompanied by clapping, rattle and drum
- Full Text: false
- Date Issued: 1997
Negotiating a comprehensive long-term relationship between South Africa and the European Union: from free trade to trade and development
- Authors: Cross, Peter John
- Date: 1997
- Subjects: Economic development -- South Africa -- 1994- , European Economic Community , European Economic Community countries -- Foreign economic relations -- South Africa , South Africa -- Foreign relations -- European Economic Community countries
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2768 , http://hdl.handle.net/10962/d1002978 , Economic development -- South Africa -- 1994- , European Economic Community , European Economic Community countries -- Foreign economic relations -- South Africa , South Africa -- Foreign relations -- European Economic Community countries
- Description: On 10 May 1994 the European Union offeredSouth Africa a package of measures to ... send a strong political signal to the incoming govemment and to the South African population, thus proving its firm determination to support the transition towards democracy and its willingness to contribute to the reconstruction and economic development of South Africa after the elections. This package consisted of two parts: 1. A series of short term implementations to take place with immediate effect to help South Africa's development and transition, and 2. An offer to negotiate a comprehensive long-term relationship with South Africa should the new government so request. South Africa accepted the European Union's offer to negotiate a long-term relationship, and in response requested membership of the structure governing the Union's relations with the rest of the countries in Sub-Saharan Africa and some countries in the Caribbean and Pacific, namely the Lomé Convention. Due to various incompatibilities South Africa was not allowed to join this organisation. In its place the European Union offered to negotiate an agreement with South Africa that would lead to a Free Trade Area. This agreement was in keeping with the rules as laid down by the World Trade Organisation. It envisaged the lowering of tariffs and trade barriers between the Union and South Africa over a period not exceeding 12 years, allowing for asymmetry in terms of time constraints in implementation only. South Africa saw this type of agreement as inconsistent with the desire expressed by the European Union to support the countries development and the integration of the Southern African region. In its place South Africa proposed a new concept in trade agreement, this concept, known as the Trade and Development Agreement, embodied both trade liberalisation and support for development. This agreement would introduce a new paradigm of thought to govern trade between developed countries and developing countries within the World Trade Organisation's rules. This paper explores the events that unfolded in these negotiations. It attempts to discover whether, in the current global environment, it is possible, or beneficial, for the developed world to act in an altruistic manner towards another state in order to assist its development.
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- Date Issued: 1997
New placoderm fishes from the Late Devonian of South Africa
- Authors: Long, John A , Anderson, M Eric , Gess, Robert W , Hiller, Norton
- Date: 1997
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/72763 , vital:30108 , https://doi.org/10.1080/02724634.1997.10010973
- Description: New placoderm fishes are described from a black shale lens in the Famennian Witpoort Formation, near Grahamstown, South Africa. Arthrodires include a new species of Groenlandaspis, G. riniensis sp. nov., a new genus of groenlandaspidid, Africanaspis doryssa gen. et sp. nov., and a new species of the antiarch Bothriolepis, B. africana sp. nov. This is the first record of the ubiquitous genera Bothriolepis and Groenlandaspis from the African continent. The South African placoderm fauna has demonstrable links with the eastern Gondwana faunas in the close affinity of the Bothriolepis africana with B. barred of Antarctica, and the high diversity of groenlandaspid species, especially the presence of a very high crested form having affinities to Tiaraspis.
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- Date Issued: 1997
Newsletter of the Self-Employed Womens Union - No.21
- Authors: SEWU
- Date: 1997
- Subjects: SEWU
- Language: Xhosa, Afrikaans
- Type: text
- Identifier: http://hdl.handle.net/10962/155026 , vital:39834
- Description: Ngomhla we 12 ku May uSEWU wamenywa ukuba azokwenza iziphakamiso kwikomiti ejongene nokulinganiswa kwabantu ngokungakhethe sini (Commission for Gender Equality)malunga nemeko yamakhosikazi azisebenzelayo. Lekomishoni yonyulwe ngo 1997. Ngethuba ekwakuqala ingxoxo zopolitiko malunga noMzantsi Afrika omtsha, kwavunyelwana ukuba urhulumente omtsha akasayi kuvumela ukuxhatshazwa kwabantu ngesini. Yaye bayakuqinisekisa ukuba kuphunyezwa umthetho kwakhiwe nepolisi ezilungiselele ukukhusela oko.
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- Date Issued: 1997
Newsletter of the Self-Employed Womens Union - No.22
- Authors: SEWU
- Date: 1997
- Subjects: SEWU
- Language: Afrikaans, Xhosa
- Type: text
- Identifier: http://hdl.handle.net/10962/155100 , vital:39855
- Description: Die Derde Jaarlikse Konferensie van SEWU sal vanaf 22 -24 Julie plaasvind. Dit is die eerste nasionale konferensie vandat SEWU buite die grense van KwaZulu- Natal begin organiseer het. Afgevaardigdes van die Wes-Kaap sal ook by hierdie Konferensie wees. SEWU lede sal afgevaardigdes uit hulle eie geledere kies om hulle by hierdie Konferensie te verteenwoordig. Daar is ongeveer 48 SEWU takke waarvan 15 in die KwaZulu-Natal se landelike gebiede is. Een afgevaardigde word vanuit elke 20 opbetaalde lede in ’n tak verkies. Ons verwag tussen 100 en 150 afgevaardigdes.
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- Date Issued: 1997
Newsletter of the Self-Employed Womens Union - No.22
- Authors: SEWU
- Date: 1997
- Subjects: SEWU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/155037 , vital:39835
- Description: Die Derde Jaarlikse Konferensie van SEWU sal vanaf 22 -24 Julie plaasvind. Dit is die eerste nasionale konferensie vandat SEWU buite die grense van KwaZulu- Natal begin organiseer het. Afgevaardigdes van die Wes-Kaap sal ook by hierdie Konferensie wees. EWU lede sal afgevaardigdes uit hulle eie geledere kies om hulle by hierdie Konferensie te verteenwoordig. Daar is ongeveer 48 SEWU takke waarvan 15 in die KwaZulu-Natal se landelike gebiede is. Een afgevaardigde word vanuit elke 20 opbetaalde lede in ’n tak verkies. Ons verwag tussen 100 en 150 afgevaardigdes.
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- Date Issued: 1997
Newspapers in education programmes and South African youth: a survey of the relationship between South African school-goers and newspapers in Esikhawini, Kwazulu-Natal
- Authors: McComb, Roslin Vanessa
- Date: 1997
- Subjects: Newspapers in education -- South Africa , School children -- South Africa -- KwaZulu-Natal -- esikhawini , Newspapers in education
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3465 , http://hdl.handle.net/10962/d1002920 , Newspapers in education -- South Africa , School children -- South Africa -- KwaZulu-Natal -- esikhawini , Newspapers in education
- Description: This study examines the relationship which scholars have with newspapers against the background of a Newspapers in Education (NIE) programme in two black South African primary schools. Considering the presence of newspapers in the class as a medium of instruction, a number of factors are found to influence the -relationship which scholars have with newspapers. These factors are: scholars' access to newspapers; the nature of lessons using the newspaper; the character of the newspaper used in NIE and the context of education at the particular schools, including the attitudes and organisational abilities of both teachers and the principal. A description and analysis of this relationship is conducted in terms of the knowledge, attitudes and behaviour which scholars had -in te1ation to newspapers. This research is qualitative, undertaken from a constructivist-interpretative approach, and is set within international and South African contexts. The findings are relevant to understanding NIE programmes' interface with scholars' educational performance and with newspaper marketing objectives, as well as to the theorisation of NIE practices.
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- Date Issued: 1997
Ngobani na
- Authors: Performer not specified , Composer not specified , Group Composition , Dargie, Dave
- Date: 1997
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Hogsback sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/342996 , vital:62955 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC342b-08
- Description: Xhosa music accompanied by uhadi
- Full Text: false
- Date Issued: 1997
Nguban' ixesha
- Authors: Performer not specified , Composer not specified , Dargie, Dave
- Date: 1997
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Hogsback sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/343109 , vital:62970 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC343a-11
- Description: Traditional xhosa music accompanied by clapping and rattle
- Full Text: false
- Date Issued: 1997
NoAndile igama lomz' wam
- Authors: Group performance , Group Composition , Dargie, Dave
- Date: 1997
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Hogsback sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/343490 , vital:63014 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC346a-03
- Description: Church music
- Full Text: false
- Date Issued: 1997
NoAndile igama lomz' wam
- Authors: Performer not specified , Composer not specified , Group Composition , Dargie, Dave
- Date: 1997
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Hogsback sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/342758 , vital:62928 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC342b-01
- Description: Xhosa music accompanied by clapping, drum and rattle
- Full Text: false
- Date Issued: 1997
NoAndile igama lomz' wam
- Authors: Performer not specified , Composer not specified , Group Composition , Dargie, Dave
- Date: 1997
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Hogsback sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/342768 , vital:62930 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC342b-02
- Description: Xhosa music accompanied by clapping, drum and rattle
- Full Text: false
- Date Issued: 1997
Nomyayi
- Authors: Hogsback festival participants , Composer not specified , Dargie, Dave
- Date: 1997
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Hogsback sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/345936 , vital:63333 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC349a-04
- Description: Xhosa music at Hogsback festival
- Full Text: false
- Date Issued: 1997
Nxaka Nxaka
- Authors: Performer not specified , Composer not specified , Dargie, Dave
- Date: 1997
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Hogsback sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/343086 , vital:62967 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC343a-08
- Description: Traditional xhosa music accompanied by clapping, rattle and drum
- Full Text: false
- Date Issued: 1997
On the life history of the lesser gurnard (Scorpaeniformes: Triglidae) inhabiting the Agulhas Bank, South Africa
- Authors: Booth, Anthony J
- Date: 1997
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125434 , vital:35782 , https://doi.10.1111/j.1095-8649.1997.tb01133.x
- Description: Fishes of the genus Labeo are widely distributed throughout Africa and consist of at least 80 species which comprise 16.4% of the African cyprinid ichthyofauna (Reid 1985). Most labeo species are also commercially important throughout the African continent, having contributed significantly to various fisheries. Their roe (sensu caviar) is often harvested as an additional bycatch (Skelton et al. 1991). Despite their obvious importance, the few studies that have investigated aspects of their life history have been conducted on the larger commercial species (Lowe 1952, Mulder 1973, Balon et al. 1974, Potgieter 1974, Baird 1976, Tomasson et al. 1984, van Zyl et al. 1995).
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- Date Issued: 1997
Paedophagia among cichlid fishes of Lake Victoria and Lake Malawi/Nyasa
- Authors: Ribbink, Aanthony J , Ribbink, A C
- Date: 1997
- Language: English
- Type: text , Article
- Identifier: vital:7134 , http://hdl.handle.net/10962/d1011777
- Description: Paedophages, as defined here, are cichlids which exploit the protective tactics of other cichlids to steal the offspring from them. The different tactics are reviewed here and a new form of paedophagy is described, in which retrieval of free-swimming young is stimulated by the paedophage so that the offspring gather at the parent's mouth, where they are readily caught by the paedophage.
- Full Text: false
- Date Issued: 1997
Painting of three African women
- Authors: Ndaba, Godfrey
- Date: 1997 , 2022-10-11
- Subjects: Bam, Brigalia
- Language: English
- Type: painting , realia
- Identifier: http://hdl.handle.net/10948/57145 , vital:57341
- Description: Dr. Brigalia Bam was gifted a painting from the Electoral Commission of Uganda. A Catholic Nun decided to give Dr. Brigalia Bam the painting of three African women because of her love and care for women. , Dr Bam told the Catholic Nun about the sad death of an Anglican Bishop who had been murdered by Idi Amin, the former President of Uganda. Dr. Brigalia Bam also focused on the stories of women widows of Uganda. , Donated/gifted to Nelson Mandela University Archives , Forms part of: Brigalia Bam collection
- Full Text: false
- Date Issued: 1997
Parasitism and invasive species : an ecological study of mussel populations
- Authors: Calvo Ugarteburu, Miren Gurutze
- Date: 1997
- Subjects: Perna -- Parasites Mytilidae -- Parasites Perna -- Ecology Mytilidae -- Ecology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5736 , http://hdl.handle.net/10962/d1005422
- Description: The Mediterranean mussel Mytilus galloprovincialis, was introduced accidentally to South Africa and has since become invasive. One possible explanation for the success of this species is that it has been released from the effects of parasites which affect the indigenous species of mussels. The aim of this work was to examine the parasitic load of different mussel populations along the southern African coast and to assess the effects of parasites on their hosts. A survey was done to quantify the levels of parasitism in indigenous populations of Perna perna from Southern Africa and of Mytilus galloprovincialis from South Africa (where it is exotic) and Spain (where it is indigenous). This survey was carried out at three different geographic scales: small scale (metres), studying the incidence of parasites within a mussel bed; medium scale (kilometres to tens of kilometres), comparing prevalences of infection among different localities; and large scale (hundreds to thousands of kilometres), examining infection rates along the Southern African coast, as well as the coast of the Basque Country (North Spain). During this survey metazoan parasites other than trematodes were rare. Four species of trematodes were commonly found infecting the indigenous mussel Perna perna. These were metacercariae of the genus Proctoeces, bucephalid sporocysts, encysted metacercariae on the labial palps and gelatinous cysts with metacercariae inside. A detailed description of Proctoeces is given; the other parasites are described elsewhere. No parasites were found in M. galloprovincialis either in South Africa or in Spain. This thesis concentrates on the study of prevalences of Proctoeces and bucephalid sporocysts and their effects on Perna perna. Infection rates with Proctoeces are highly dependent on the sex of the host, with more females than males being infected, and are also size dependent, though only for females. Identification of the sex of mussels infected with bucephalid sporocysts is often not possible since the sporocysts spread over the gonad and replace it. Prevalence of infection with this parasite also increases with the size of the host. To study the influence of Proctoeces and bucephalid sporocysts on the ecological fitness of Perna perna, their effects on survival and competitive ability were tested. The results showed significant negative effects. Both parasites significantly depressed condition but only after spawning, when the mussels were already stressed. In order to check for effects on host survival, the effects of both parasites on mortality rates, gaping behaviour and water loss of mussels exposed to air were also examined. Neither parasite affected mortality rate or gaping behaviour of Perna perna. Proctoeces did not affect the amount of water lost by mussels, but the bucephalid sporocysts did. Mussels infected with sporocysts lost significantly more water than non-infected individuals. This increase in water loss was not related to the gaping behaviour, but a test of the strength of the adductor muscles showed that less force was needed to open mussels with bucephalid sporocysts than non-infected mussels. This was not the case for mussels infected by Proctoeces. Weaker mussels will fail to seal the valves properly, resulting in an increase of water loss on exposure to air by evaporation. Another factor that will have an obvious effect on a population is the reproductive output of the animals. Histological sections of the gonad of infected and non-infected females were cut to study the effects of both parasites on reproduction. Statistical tests comparing the numbers and sizes of oocytes in females infected with Proctoeces and non-infected females showed no significant differences. However, bucephalid sporocysts have a dramatic effect on reproduction by castrating the host, leaving no trace of sex products. One of the major factors shaping the composition of a mussel bed is competition for space and food, with smaller mussels being at a competitive disadvantage. Thus, in order to examine effects of both parasites on the competitive ability of Perna perna, summer and winter growth rates were compared for infected and non-infected mussels. Proctoeces reduced growth both in summer and in winter whilst bucephalid sporocysts had no significant effect. Both growth and reproduction are important components of the energy budget of an animal, and each is affected by either Proctoeces or the bucephalid sporocysts. In an attempt to test if Perna perna compensates energetically for these negative effects, filtration rates and oxygen consumption of mussels with and without parasites were measured. Neither parasite had a significant effect on filtration rates or oxygen consumption of the host. All these results indicate that both Proctoeces and the bucephalid sporocysts have a detrimental effect on their host, and that the mussels do not compensate for these negative effects. There is neither an increase in filtration, nor a decrease in respiration to balance the energy lost to the parasite. The two parasites studied affect the host in different but complementary ways. The effects of both parasites are concentrated on those size classes of mussel which channel most energy into the portion of the energy budget affected by the parasite. Proctoeces affects growth only in the smaller individuals, which under normal conditions would put most energy into growth; and the bucephalid sporocysts castrate the bigger mussels, which would expend most energy on reproduction. By reducing growth rates of small mussels or castrating large mussels, these parasites effectively remove them from the breeding population and reduce their competitive abilities. These negative effects, together with the high prevalence of both parasites in Perna perna along the South African coast and their absence in Mytilus galloprovincialis, suggest that parasites may be an important reason for the success of Mytilus.
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- Date Issued: 1997