Implementing the GrabCut segmentation technique as a plugin for the GIMP
- Marsh, Matthew, Bangay, Shaun D, Lobb, Adele
- Authors: Marsh, Matthew , Bangay, Shaun D , Lobb, Adele
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433207 , vital:72951 , https://doi.org/10.1145/1108590.1108618
- Description: Image segmentation requires a segmentation tool that is fast and easy to use. The GIMP has built in segmentation tools, but under some circumstances these tools perform badly. "GrabCut" is an innovative segmentation technique that uses both region and boundary information in order to perform segmentation. Several variations on the "GrabCut" algorithm have been implemented as a plugin for the GIMP. The results obtained using "GrabCut" are comparable, and often better than the results of all the other built in segmentation tools.
- Full Text:
- Date Issued: 2006
- Authors: Marsh, Matthew , Bangay, Shaun D , Lobb, Adele
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433207 , vital:72951 , https://doi.org/10.1145/1108590.1108618
- Description: Image segmentation requires a segmentation tool that is fast and easy to use. The GIMP has built in segmentation tools, but under some circumstances these tools perform badly. "GrabCut" is an innovative segmentation technique that uses both region and boundary information in order to perform segmentation. Several variations on the "GrabCut" algorithm have been implemented as a plugin for the GIMP. The results obtained using "GrabCut" are comparable, and often better than the results of all the other built in segmentation tools.
- Full Text:
- Date Issued: 2006
Indigenous languages and the media in South Africa:
- Authors: Kaschula, Russell H
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/175137 , vital:42546 , https://hdl.handle.net/10520/EJC15168
- Description: This article explores the status of South Africa’s indigenous languages and how they are being used in the media. More specifically, the performance of these languages in the print media, the broadcasting media and the Internet, is outlined. This is done against the backdrop of the South African Constitution, Section 6, which entrenches eleven official languages. Contrary to the Constitution’s provisions, it is found that the indigenous languages are achieving varying levels of success within the media. The reasons for this are outlined. Finally, the effects of globalisation on the indigenous languages within the media are assessed.
- Full Text:
- Date Issued: 2006
- Authors: Kaschula, Russell H
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/175137 , vital:42546 , https://hdl.handle.net/10520/EJC15168
- Description: This article explores the status of South Africa’s indigenous languages and how they are being used in the media. More specifically, the performance of these languages in the print media, the broadcasting media and the Internet, is outlined. This is done against the backdrop of the South African Constitution, Section 6, which entrenches eleven official languages. Contrary to the Constitution’s provisions, it is found that the indigenous languages are achieving varying levels of success within the media. The reasons for this are outlined. Finally, the effects of globalisation on the indigenous languages within the media are assessed.
- Full Text:
- Date Issued: 2006
Inetvis, a visual tool for network telescope traffic analysis
- van Riel, Jean-Pierre, Irwin, Barry V W
- Authors: van Riel, Jean-Pierre , Irwin, Barry V W
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430176 , vital:72671 , https://doi.org/10.1145/1108590.1108604
- Description: This article illustrates the merits of visual analysis as it presents prelimi-nary findings using InetVis - an animated 3-D scatter plot visualization of network events. The concepts and features of InetVis are evaluated with reference to related work in the field. Tested against a network scanning tool, anticipated visual signs of port scanning and network mapping serve as a proof of concept. This research also unveils sub-stantial amounts of suspicious activity present in Internet traffic during August 2005, as captured by a class C network telescope. InetVis is found to have promising scalability whilst offering salient depictions of intrusive network activity.
- Full Text:
- Date Issued: 2006
- Authors: van Riel, Jean-Pierre , Irwin, Barry V W
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430176 , vital:72671 , https://doi.org/10.1145/1108590.1108604
- Description: This article illustrates the merits of visual analysis as it presents prelimi-nary findings using InetVis - an animated 3-D scatter plot visualization of network events. The concepts and features of InetVis are evaluated with reference to related work in the field. Tested against a network scanning tool, anticipated visual signs of port scanning and network mapping serve as a proof of concept. This research also unveils sub-stantial amounts of suspicious activity present in Internet traffic during August 2005, as captured by a class C network telescope. InetVis is found to have promising scalability whilst offering salient depictions of intrusive network activity.
- Full Text:
- Date Issued: 2006
Integrating Secure RTP into the Open Source VoIP PBX Asterisk
- Clayton, Bradley, Irwin, Barry V W, Terzoli, Alfredo
- Authors: Clayton, Bradley , Irwin, Barry V W , Terzoli, Alfredo
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428735 , vital:72532 , https://d1wqtxts1xzle7.cloudfront.net/84872934/66_Paper-libre.pdf?1650920302=response-content-disposi-tion=inline%3B+filename%3DIntegrating_Secure_RTP_into_the_Open_Sou.pdfExpires=1714744382Signature=PijjCGW0qcvkqRe-2R55HocKLvz9Ljw8jmhQvRQEi9YqJl7eWSiYnvs9CogY4u4bmDTYTLpvkA-nlfbiszg-s7Cq2nbLn3PUdfJ5cA11ujboi~i7oSoem7smuN1YCVZlg7FnZRd6mOXdTry9UAh8TlWyndF6pY1RXtc7bgb5cWeK4ggJ7~bM0HUXEbUKKa-abCZnGNrAZ59JIdL6CNx1Sht3o5mZTcyRL3PNVSOz17lldXi4FsAOEUwsVV-uv04hzp6pe6Qv5WbAP6tqk7deyoLUwk58A9F-PaJlOLy2gDAVLnbKT8RrxYg8tqv8SuBhPWb32CefBxv486N3F6izZw__Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: Implementations of Voice over Internet Protocol (VoIP) have focused, up to now, mainly on the need to transport data in real-time, often at the expense of security. The neglect of secure VoIP is often intentional, as developers are striving to minimise overheads and delays. The Secure Real-Time Protocol (SRTP) has the potential to secure real-time streams without exacting too high a performance price. SRTP is the addition of security to the audio/video profile used in the Real-Time Transport Protocol (RTP). SRTP adds confidentiality, integrity and op-tionaly authenticity to RTP media streams. This paper focuses on the integration of SRTP into Asterisk, an open-source VoIP PBX. SRTP support has recently been added to Asterisk by Mikael Magnusson. This paper analyses Magnusson’s implementation, contrasting it to a proof-of-concept implementation developed independently at Rhodes University. The interoperability of SRTP implementations cannot be taken for granted, given the relatively recent standardization of the pro-tocol, and so Magnusson’s implementation is tested against another SRTP implementation. Finally, the paper highlights a major shortcoming in Magnusson’s implementation, namely that the exchange of encryp-tion keys is done in the clear. It concludes by proposing possible solu-tions, such as TLS, IPSec and MIkey.
- Full Text:
- Date Issued: 2006
- Authors: Clayton, Bradley , Irwin, Barry V W , Terzoli, Alfredo
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428735 , vital:72532 , https://d1wqtxts1xzle7.cloudfront.net/84872934/66_Paper-libre.pdf?1650920302=response-content-disposi-tion=inline%3B+filename%3DIntegrating_Secure_RTP_into_the_Open_Sou.pdfExpires=1714744382Signature=PijjCGW0qcvkqRe-2R55HocKLvz9Ljw8jmhQvRQEi9YqJl7eWSiYnvs9CogY4u4bmDTYTLpvkA-nlfbiszg-s7Cq2nbLn3PUdfJ5cA11ujboi~i7oSoem7smuN1YCVZlg7FnZRd6mOXdTry9UAh8TlWyndF6pY1RXtc7bgb5cWeK4ggJ7~bM0HUXEbUKKa-abCZnGNrAZ59JIdL6CNx1Sht3o5mZTcyRL3PNVSOz17lldXi4FsAOEUwsVV-uv04hzp6pe6Qv5WbAP6tqk7deyoLUwk58A9F-PaJlOLy2gDAVLnbKT8RrxYg8tqv8SuBhPWb32CefBxv486N3F6izZw__Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: Implementations of Voice over Internet Protocol (VoIP) have focused, up to now, mainly on the need to transport data in real-time, often at the expense of security. The neglect of secure VoIP is often intentional, as developers are striving to minimise overheads and delays. The Secure Real-Time Protocol (SRTP) has the potential to secure real-time streams without exacting too high a performance price. SRTP is the addition of security to the audio/video profile used in the Real-Time Transport Protocol (RTP). SRTP adds confidentiality, integrity and op-tionaly authenticity to RTP media streams. This paper focuses on the integration of SRTP into Asterisk, an open-source VoIP PBX. SRTP support has recently been added to Asterisk by Mikael Magnusson. This paper analyses Magnusson’s implementation, contrasting it to a proof-of-concept implementation developed independently at Rhodes University. The interoperability of SRTP implementations cannot be taken for granted, given the relatively recent standardization of the pro-tocol, and so Magnusson’s implementation is tested against another SRTP implementation. Finally, the paper highlights a major shortcoming in Magnusson’s implementation, namely that the exchange of encryp-tion keys is done in the clear. It concludes by proposing possible solu-tions, such as TLS, IPSec and MIkey.
- Full Text:
- Date Issued: 2006
Interactions of fishes with particular reference to coelacanths in the canyons at Sodwana Bay and the St Lucia Marine Protected Area of South Africa
- Heemstra, Phillip C, Frickle, H, Hissmann, K
- Authors: Heemstra, Phillip C , Frickle, H , Hissmann, K
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7130 , http://hdl.handle.net/10962/d1011771
- Description: The deep demersal fish fauna at depths of 100–400min canyons off the St Lucia Marine Protected Area along the north coast of KwaZulu-Natal is compared with similar fish communities at the Comoro Islands and in the Indo-Pacific region. Fifty-four fish species were seen or photographed from the submersible Jago or by the discovery team of scuba divers in the coelacanth, Latimeria chalumnae, habitat of the canyons off Sodwana Bay. An additional 94 fish species known from depths of 100–200 m along the coast of northern KwaZulu-Natal are likely to occur in the canyon habitat. The fish fauna of the Sodwana canyons shares at least 18 species with the deep demersal fish community off tropical coral reefs of the Indo-Pacific region. Thirty-seven of the Sodwana canyon fishes are also known from the coelacanth habitat in the Comoros.
- Full Text:
- Date Issued: 2006
- Authors: Heemstra, Phillip C , Frickle, H , Hissmann, K
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7130 , http://hdl.handle.net/10962/d1011771
- Description: The deep demersal fish fauna at depths of 100–400min canyons off the St Lucia Marine Protected Area along the north coast of KwaZulu-Natal is compared with similar fish communities at the Comoro Islands and in the Indo-Pacific region. Fifty-four fish species were seen or photographed from the submersible Jago or by the discovery team of scuba divers in the coelacanth, Latimeria chalumnae, habitat of the canyons off Sodwana Bay. An additional 94 fish species known from depths of 100–200 m along the coast of northern KwaZulu-Natal are likely to occur in the canyon habitat. The fish fauna of the Sodwana canyons shares at least 18 species with the deep demersal fish community off tropical coral reefs of the Indo-Pacific region. Thirty-seven of the Sodwana canyon fishes are also known from the coelacanth habitat in the Comoros.
- Full Text:
- Date Issued: 2006
Is economic impact a good way of justifying the inclusion of foreign students at local universities?
- Snowball, Jeanette D, Antrobus, Geoffrey G
- Authors: Snowball, Jeanette D , Antrobus, Geoffrey G
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67470 , vital:29098 , http://dx.doi.org/10.4314/sajhe.v20i3.25593
- Description: Pre-print , In the debate surrounding the costs and benefits of having foreign students at South African universities, the financial contributions of foreign students to their host economies is sometimes cited. This article reports the results of a comparison between the economic impact on the Grahamstown economy of the spending of foreign and local students at Rhodes University. It finds that the spending patterns of both types of students are remarkably similar and that the somewhat higher economic impact of foreign students is largely as a result of their propensity to choose the more expensive residence accommodation, rather than as a result of greater average spending generally. We suggest that economic impact studies should be used with caution when making the case for continued public subsidy of goods with significant non-market values and that opportunity costs should also be considered.
- Full Text:
- Date Issued: 2006
Is economic impact a good way of justifying the inclusion of foreign students at local universities?
- Authors: Snowball, Jeanette D , Antrobus, Geoffrey G
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67470 , vital:29098 , http://dx.doi.org/10.4314/sajhe.v20i3.25593
- Description: Pre-print , In the debate surrounding the costs and benefits of having foreign students at South African universities, the financial contributions of foreign students to their host economies is sometimes cited. This article reports the results of a comparison between the economic impact on the Grahamstown economy of the spending of foreign and local students at Rhodes University. It finds that the spending patterns of both types of students are remarkably similar and that the somewhat higher economic impact of foreign students is largely as a result of their propensity to choose the more expensive residence accommodation, rather than as a result of greater average spending generally. We suggest that economic impact studies should be used with caution when making the case for continued public subsidy of goods with significant non-market values and that opportunity costs should also be considered.
- Full Text:
- Date Issued: 2006
Izaci namaqhalo esiXhosa: Xhosa idioms and proverbs referring to plants
- Cocks, Michelle L, Dold, Anthony P
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141326 , vital:37962 , https://hdl.handle.net/10520/EJC112940
- Description: Converging with the ecological extinction crisis, the planet has been experiencing a severe erosion of the diversity of human cultures and languages, reducing the pool of knowledge, behaviors and values from which individual communities and humanity at large can draw to respond to social and environmental stresses.
- Full Text:
- Date Issued: 2006
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141326 , vital:37962 , https://hdl.handle.net/10520/EJC112940
- Description: Converging with the ecological extinction crisis, the planet has been experiencing a severe erosion of the diversity of human cultures and languages, reducing the pool of knowledge, behaviors and values from which individual communities and humanity at large can draw to respond to social and environmental stresses.
- Full Text:
- Date Issued: 2006
JM Coetzee's Disgrace and the Task of the Imagination:
- Authors: Marais, Mike
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144126 , vital:38313 , DOI: 10.2979/JML.2006.29.2.75
- Description: In an early review of Disgrace, Jane Taylor first relates this novel's treatment of violence in post-apartheid South Africa to the European Enlightenment's legacy of the autonomy of the human subject (25), in terms of which each individual is conceived of as a living consciousness separated totally from every other consciousness, and then discusses J.M. Coetzee's postulation of the sympathetic imagination as a potential corrective to the violence attendant on monadic individuality. Taylor makes the telling point that, in the eighteenth century, the notions of sensibility, sympathy, and compassion, which the novel repeatedly invokes, were self-consciously developed as an ethical response to the instrumentalist logic of autonomous individuality and, in this regard, she cites Adam Smith's observation in The Theory of Moral Sentiments that "By the imagination we place ourselves in his situation, we conceive ourselves enduring all the same torments, we enter as it were into his body, and become in some measure the same person with him, and thence form some idea of his sensation" (qtd. in Taylor 25).
- Full Text:
- Date Issued: 2006
- Authors: Marais, Mike
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144126 , vital:38313 , DOI: 10.2979/JML.2006.29.2.75
- Description: In an early review of Disgrace, Jane Taylor first relates this novel's treatment of violence in post-apartheid South Africa to the European Enlightenment's legacy of the autonomy of the human subject (25), in terms of which each individual is conceived of as a living consciousness separated totally from every other consciousness, and then discusses J.M. Coetzee's postulation of the sympathetic imagination as a potential corrective to the violence attendant on monadic individuality. Taylor makes the telling point that, in the eighteenth century, the notions of sensibility, sympathy, and compassion, which the novel repeatedly invokes, were self-consciously developed as an ethical response to the instrumentalist logic of autonomous individuality and, in this regard, she cites Adam Smith's observation in The Theory of Moral Sentiments that "By the imagination we place ourselves in his situation, we conceive ourselves enduring all the same torments, we enter as it were into his body, and become in some measure the same person with him, and thence form some idea of his sensation" (qtd. in Taylor 25).
- Full Text:
- Date Issued: 2006
Joking around in Zimbabwe, undoing and redoing participation
- Authors: Price, Leigh
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373715 , vital:66716 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122750"
- Description: In Zimbabwe, I teach a participatory course on environmental education to trainers. The course is an adaptation of a course designed by Rhodes University, South Africa. It gives participants a background in educational theories and has a strong theoretical component built around a focus on practice. During the time that the course was being delivered to non-industry participants, the theoretical component of the course was whole-heartedly embraced. We assumed that calling the course ‘participatory’ presupposed the need for this theory because within the theory were the tools for emancipation. And participation, we believed, had an emancipatory mandate. However, when we decided to redevelop the course for industry, we were uncomfortably surprised by the request from a majority of industry participants to reduce the theory and concentrate solely on skills-based training. This paper documents how this discomfort resulted in my adjusting my view of participation.
- Full Text:
- Date Issued: 2006
- Authors: Price, Leigh
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373715 , vital:66716 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122750"
- Description: In Zimbabwe, I teach a participatory course on environmental education to trainers. The course is an adaptation of a course designed by Rhodes University, South Africa. It gives participants a background in educational theories and has a strong theoretical component built around a focus on practice. During the time that the course was being delivered to non-industry participants, the theoretical component of the course was whole-heartedly embraced. We assumed that calling the course ‘participatory’ presupposed the need for this theory because within the theory were the tools for emancipation. And participation, we believed, had an emancipatory mandate. However, when we decided to redevelop the course for industry, we were uncomfortably surprised by the request from a majority of industry participants to reduce the theory and concentrate solely on skills-based training. This paper documents how this discomfort resulted in my adjusting my view of participation.
- Full Text:
- Date Issued: 2006
Labouring to love: romantic love and power in the construction of middle-class femininity
- Vincent, Louise, McEwen, Caryn
- Authors: Vincent, Louise , McEwen, Caryn
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141783 , vital:38004 , DOI: 10.1177/097152150501300102
- Description: South Africa is 10 years into its new democratic order. An aspect of the country's political transformation has been an official political commitment to gender trans-formation. While great strides have been made towards greater gender equality at the institutional and legal level of society, the present article suggests that highly unequal power relations between men and women continue to be perpetuated in unexpected ways among those whom we would most expect to be capable of resistance. This paper is about how subtle yet deeply embedded ideologies and practices within heterosexual relationships serve to keep highly educated, apparently empowered and liberated women ‘in their place’, ensuring that they do not fulfil their potential. Traditionally women were socialised into assuming their positions in the home as caregivers and unpaid household labourers. The hope of feminism was that education, economic empowerment and an ideology of ‘can do’ independence would liberate women. However, for many women, it is in the most intimate aspects of their lives—in their sexual relationships with men—that this hope continues to be thwarted.
- Full Text:
- Date Issued: 2006
- Authors: Vincent, Louise , McEwen, Caryn
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141783 , vital:38004 , DOI: 10.1177/097152150501300102
- Description: South Africa is 10 years into its new democratic order. An aspect of the country's political transformation has been an official political commitment to gender trans-formation. While great strides have been made towards greater gender equality at the institutional and legal level of society, the present article suggests that highly unequal power relations between men and women continue to be perpetuated in unexpected ways among those whom we would most expect to be capable of resistance. This paper is about how subtle yet deeply embedded ideologies and practices within heterosexual relationships serve to keep highly educated, apparently empowered and liberated women ‘in their place’, ensuring that they do not fulfil their potential. Traditionally women were socialised into assuming their positions in the home as caregivers and unpaid household labourers. The hope of feminism was that education, economic empowerment and an ideology of ‘can do’ independence would liberate women. However, for many women, it is in the most intimate aspects of their lives—in their sexual relationships with men—that this hope continues to be thwarted.
- Full Text:
- Date Issued: 2006
Language and learning science in South Africa
- Authors: Probyn, Margie J
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7023 , http://hdl.handle.net/10962/d1007204 , http://dx.doi.org/10.2167/le554.0
- Description: South Africa is a multilingual country with 11 official languages. However, English dominates as the language of access and power and although the Language-in- Education Policy (1997) recommends school language policies that will promote additive bilingualism and the use of learners' home languages as languages of learning and teaching, there has been little implementation of these recommendations by schools. This is despite the fact that the majority of learners do not have the necessary English language proficiency to successfully engage with the curriculum and that teachers frequently are obliged to resort to using the learners' home language to mediate understanding. This research investigates the classroom language practices of six Grade 8 science teachers, teaching science through the medium of English where they and their learners share a common home language, Xhosa. Teachers' lessons were videotaped, transcribed and analysed for the opportunities they offered learners for language development and conceptual challenge. The purpose of the research is to better understand the teachers' perceptions and problems and to be able to draw on examples of good practice, to inform teacher training and to develop a coherent bilingual approach for teaching science through the medium of English as an additional language.
- Full Text:
- Date Issued: 2006
- Authors: Probyn, Margie J
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7023 , http://hdl.handle.net/10962/d1007204 , http://dx.doi.org/10.2167/le554.0
- Description: South Africa is a multilingual country with 11 official languages. However, English dominates as the language of access and power and although the Language-in- Education Policy (1997) recommends school language policies that will promote additive bilingualism and the use of learners' home languages as languages of learning and teaching, there has been little implementation of these recommendations by schools. This is despite the fact that the majority of learners do not have the necessary English language proficiency to successfully engage with the curriculum and that teachers frequently are obliged to resort to using the learners' home language to mediate understanding. This research investigates the classroom language practices of six Grade 8 science teachers, teaching science through the medium of English where they and their learners share a common home language, Xhosa. Teachers' lessons were videotaped, transcribed and analysed for the opportunities they offered learners for language development and conceptual challenge. The purpose of the research is to better understand the teachers' perceptions and problems and to be able to draw on examples of good practice, to inform teacher training and to develop a coherent bilingual approach for teaching science through the medium of English as an additional language.
- Full Text:
- Date Issued: 2006
Larval development of the carrion-breeding flesh fly, Sarcophaga (Liosarcophaga) tibialis Macquart (Diptera: Sarcophagidae), at constant temperatures
- Villet, Martin H, MacKenzie, B, Muller, Wilhelmine J
- Authors: Villet, Martin H , MacKenzie, B , Muller, Wilhelmine J
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7091 , http://hdl.handle.net/10962/d1012422
- Description: Larvae of Sarcophaga (Liosarcophaga) tibialis Macquart were raised on chicken liver under six different constant temperatures. Maximum survival indicated an optimal developmental temperature of near 20°C, while trends in mortality, larval length and larval mass implied that the thermal window for successful development lay between 15°C and 30°C. Using a recently described method to estimate a simple thermal summation model, it was found that the timing of the end of the feeding phase could be estimated by a developmental zero (D0) of 5.2°C (S.E. = 1.21) and a thermal summation constant (K) of 106.4 d°C (S.E. = 8.31) and of the end of the wandering phase by D0 = 4.1°C (S.E. = 0.39) and K = 126.7 d°C (S.E. = 3.28). Published development times at constant temperatures were compiled for 19 other species of flesh flies, and the developmental constants were calculated for six species for which sufficient data were accumulated.
- Full Text:
- Date Issued: 2006
- Authors: Villet, Martin H , MacKenzie, B , Muller, Wilhelmine J
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7091 , http://hdl.handle.net/10962/d1012422
- Description: Larvae of Sarcophaga (Liosarcophaga) tibialis Macquart were raised on chicken liver under six different constant temperatures. Maximum survival indicated an optimal developmental temperature of near 20°C, while trends in mortality, larval length and larval mass implied that the thermal window for successful development lay between 15°C and 30°C. Using a recently described method to estimate a simple thermal summation model, it was found that the timing of the end of the feeding phase could be estimated by a developmental zero (D0) of 5.2°C (S.E. = 1.21) and a thermal summation constant (K) of 106.4 d°C (S.E. = 8.31) and of the end of the wandering phase by D0 = 4.1°C (S.E. = 0.39) and K = 126.7 d°C (S.E. = 3.28). Published development times at constant temperatures were compiled for 19 other species of flesh flies, and the developmental constants were calculated for six species for which sufficient data were accumulated.
- Full Text:
- Date Issued: 2006
Lattice-valued continuous convergence is induced by a lattice-valued uniform convergence structure
- Authors: Jäger, Gunter
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6824 , http://hdl.handle.net/10962/d1012332
- Description: We define a stratified L-uniform convergence structure on the set of all continuous mappings from a stratified L-limit space to a stratified L-uniform convergence space. This structure induces L-continuous convergence. This shows that the category of all L-limit-uniformizable spaces is cartesian closed.
- Full Text:
- Date Issued: 2006
- Authors: Jäger, Gunter
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6824 , http://hdl.handle.net/10962/d1012332
- Description: We define a stratified L-uniform convergence structure on the set of all continuous mappings from a stratified L-limit space to a stratified L-uniform convergence space. This structure induces L-continuous convergence. This shows that the category of all L-limit-uniformizable spaces is cartesian closed.
- Full Text:
- Date Issued: 2006
Learning about participation in integrated water resources management: A South African review
- Burt, Jane, du Toit, Derick, Neves, David, Pollard, Sharon
- Authors: Burt, Jane , du Toit, Derick , Neves, David , Pollard, Sharon
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433025 , vital:72924 , xlink:href="https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/TT293-06.pdf"
- Description: The National Water Act (1998) opens the way for ordinary people to take part in water resource management (WRM). This is a significant move towards a more social orientation and away from an approach that focused almost exclusively on the technical aspects of WRM. This set of two books asks what a social orientation means in practice. Since the National Water Act became law in 1998, how have WRM practitioners involved people in the process of managing water? What have we learnt so far? And how can we use these lessons to move forward? The content of the books is based on research that looked in some depth at national and local participatory practice in South Africa, and also broadly at international trends. The research was conducted by three WRM practitioners and two researchers in the field of participatory approaches.
- Full Text:
- Date Issued: 2006
- Authors: Burt, Jane , du Toit, Derick , Neves, David , Pollard, Sharon
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433025 , vital:72924 , xlink:href="https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/TT293-06.pdf"
- Description: The National Water Act (1998) opens the way for ordinary people to take part in water resource management (WRM). This is a significant move towards a more social orientation and away from an approach that focused almost exclusively on the technical aspects of WRM. This set of two books asks what a social orientation means in practice. Since the National Water Act became law in 1998, how have WRM practitioners involved people in the process of managing water? What have we learnt so far? And how can we use these lessons to move forward? The content of the books is based on research that looked in some depth at national and local participatory practice in South Africa, and also broadly at international trends. The research was conducted by three WRM practitioners and two researchers in the field of participatory approaches.
- Full Text:
- Date Issued: 2006
Managing South Africa's trawl bycatch
- Walmsley, Sarah A, Leslie, Rob W, Sauer, Warwick H H
- Authors: Walmsley, Sarah A , Leslie, Rob W , Sauer, Warwick H H
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124954 , vital:35713 , https://doi.10.1093/icesjms/fsl022
- Description: Over the past few decades, it has become widely recognized that the management strategies of world fisheries must ensure sustainability of bycatch as well as of target species. South Africa implemented a pilot observer programme from 1995 to 2000 to collect data on the levels and patterns of bycatch and discards in the demersal trawl fishery. Here, the results of that programme are used in conjunction with information on bycatch value and compliance to assess the issues and problems regarding bycatch and discarding in the fishery. In general, bycatch components can be placed into one of three categories (discarded bycatch, retained bycatch, and processing waste), each of which present different management problems and require different management approaches. The results were used to formulate a bycatch management plan for the demersal trawl fishery in South Africa. Given the need to continue monitoring bycatch, the performance of the pilot observer programme is reviewed, and the levels of sampling effort required for a national programme are discussed.
- Full Text:
- Date Issued: 2006
- Authors: Walmsley, Sarah A , Leslie, Rob W , Sauer, Warwick H H
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124954 , vital:35713 , https://doi.10.1093/icesjms/fsl022
- Description: Over the past few decades, it has become widely recognized that the management strategies of world fisheries must ensure sustainability of bycatch as well as of target species. South Africa implemented a pilot observer programme from 1995 to 2000 to collect data on the levels and patterns of bycatch and discards in the demersal trawl fishery. Here, the results of that programme are used in conjunction with information on bycatch value and compliance to assess the issues and problems regarding bycatch and discarding in the fishery. In general, bycatch components can be placed into one of three categories (discarded bycatch, retained bycatch, and processing waste), each of which present different management problems and require different management approaches. The results were used to formulate a bycatch management plan for the demersal trawl fishery in South Africa. Given the need to continue monitoring bycatch, the performance of the pilot observer programme is reviewed, and the levels of sampling effort required for a national programme are discussed.
- Full Text:
- Date Issued: 2006
Methinks he doth protest too much - recovering unjustified payments made under duress and protest
- Authors: Glover, Graham B
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70744 , vital:29724 , https://hdl.handle.net/10520/EJC55014
- Description: The private law doctrine of duress, although mostly discussed in the context of the law of contract in South Africa, is also relevant in the law of unjustified enrichment. Where an unjustified payment or transfer of some kind has been induced by duress, in a situation where there is no contractual relationship between the parties, the aggrieved party will be entitled to reclaim the payment or transfer. The principles of enrichment law will apply in such cases.
- Full Text: false
- Date Issued: 2006
- Authors: Glover, Graham B
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70744 , vital:29724 , https://hdl.handle.net/10520/EJC55014
- Description: The private law doctrine of duress, although mostly discussed in the context of the law of contract in South Africa, is also relevant in the law of unjustified enrichment. Where an unjustified payment or transfer of some kind has been induced by duress, in a situation where there is no contractual relationship between the parties, the aggrieved party will be entitled to reclaim the payment or transfer. The principles of enrichment law will apply in such cases.
- Full Text: false
- Date Issued: 2006
Mlanjeni's war charms: Ikhubalo likaMlanjeni
- Cocks, Michelle L, Dold, Anthony P
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141349 , vital:37964 , https://hdl.handle.net/10520/EJC112911
- Description: Most South Africans are familiar with lucky charms such as the four leaved clover of European origin, the Hamsa Hand (Arabic) or Hamesh Hand (Hebrew), the Hindu lucky elephant representing Ganesha, son of Siva, or the African ikhubalo. Amakhubalo refer to charms, often of plant origin, that have magical powers to ward off danger or to bring good luck. Charm plants are used almost everywhere in the Eastern Cape to ensure health, luck and success in sporting events, business, courtship, legal proceedings, safety against accidents and crime and protection against jealousy and sorcery.
- Full Text:
- Date Issued: 2006
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141349 , vital:37964 , https://hdl.handle.net/10520/EJC112911
- Description: Most South Africans are familiar with lucky charms such as the four leaved clover of European origin, the Hamsa Hand (Arabic) or Hamesh Hand (Hebrew), the Hindu lucky elephant representing Ganesha, son of Siva, or the African ikhubalo. Amakhubalo refer to charms, often of plant origin, that have magical powers to ward off danger or to bring good luck. Charm plants are used almost everywhere in the Eastern Cape to ensure health, luck and success in sporting events, business, courtship, legal proceedings, safety against accidents and crime and protection against jealousy and sorcery.
- Full Text:
- Date Issued: 2006
Monthly Patch Release Schedules: Do the Benefits Outweigh the Risks?
- White, Dominic, Irwin, Barry V W
- Authors: White, Dominic , Irwin, Barry V W
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428749 , vital:72533 , https://www.academia.edu/29214940/A_Unified_Patch_Management_Architecture
- Description: This paper attempts to address the issue of hardening the internal security of an or-ganisation’s network by easing its patch management. A unified architecture to aid with this process is proposed, with the view towards the implementation of an open source, cross platform tool to solve this problem.
- Full Text:
- Date Issued: 2006
- Authors: White, Dominic , Irwin, Barry V W
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428749 , vital:72533 , https://www.academia.edu/29214940/A_Unified_Patch_Management_Architecture
- Description: This paper attempts to address the issue of hardening the internal security of an or-ganisation’s network by easing its patch management. A unified architecture to aid with this process is proposed, with the view towards the implementation of an open source, cross platform tool to solve this problem.
- Full Text:
- Date Issued: 2006
Near-real time foF2 predictions using neural networks
- Oyeyemi, E O, McKinnell, Lee-Anne, Poole, Allon W V
- Authors: Oyeyemi, E O , McKinnell, Lee-Anne , Poole, Allon W V
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6804 , http://hdl.handle.net/10962/d1004167
- Description: This paper describes the use of the neural network (NN) technique for the development of a near-real time global foF2 (NRTNN) empirical model. The data used are hourly daily values of foF2 from 26 worldwide ionospheric stations (based on availability) during the period 1976–1986 for training the NN and between 1977 and 1989 for verifying the prediction accuracy. The training data set includes all periods of quiet and disturbed geomagnetic conditions. Two categories of input parameters were used as inputs to the NN. The first category consists of geophysical parameters that are temporally or spatially related to the training stations. The second category, which is related to the foF2 itself, consists of three recent past observations of foF2 (i.e. real-time foF2 (F0), 2 h (F−2) and 1 h (F−1) prior to F0) from four control stations (i.e. Boulder (40.0°N, 254.7°E), Grahamstown (33.3°S, 26.5°E), Dourbes (50.1°N, 4.6°E) and Port Stanley (51.7°S, 302.2°E). The performance of the NRTNN was verified under both geomagnetically quiet and disturbed conditions with observed data from a few verification stations. A comparison of the root mean square error (RMSE) differences between measured values and the NRTNN predictions with our earlier standard foF2 NN empirical model is also illustrated. The results reveal that NRTNN will predict foF2 in near-real time with about 1 MHz RMSE difference anywhere on the globe, provided real time data is available at the four control stations. From the results it is also evident that in addition to the geophysical information from any geographical location, recent past observations of foF2 from these control stations could be used as inputs to a NN for near-real time foF2 predictions. Results also reveal that there is a temporal correlation between measured foF2 values at different locations.
- Full Text:
- Date Issued: 2006
- Authors: Oyeyemi, E O , McKinnell, Lee-Anne , Poole, Allon W V
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6804 , http://hdl.handle.net/10962/d1004167
- Description: This paper describes the use of the neural network (NN) technique for the development of a near-real time global foF2 (NRTNN) empirical model. The data used are hourly daily values of foF2 from 26 worldwide ionospheric stations (based on availability) during the period 1976–1986 for training the NN and between 1977 and 1989 for verifying the prediction accuracy. The training data set includes all periods of quiet and disturbed geomagnetic conditions. Two categories of input parameters were used as inputs to the NN. The first category consists of geophysical parameters that are temporally or spatially related to the training stations. The second category, which is related to the foF2 itself, consists of three recent past observations of foF2 (i.e. real-time foF2 (F0), 2 h (F−2) and 1 h (F−1) prior to F0) from four control stations (i.e. Boulder (40.0°N, 254.7°E), Grahamstown (33.3°S, 26.5°E), Dourbes (50.1°N, 4.6°E) and Port Stanley (51.7°S, 302.2°E). The performance of the NRTNN was verified under both geomagnetically quiet and disturbed conditions with observed data from a few verification stations. A comparison of the root mean square error (RMSE) differences between measured values and the NRTNN predictions with our earlier standard foF2 NN empirical model is also illustrated. The results reveal that NRTNN will predict foF2 in near-real time with about 1 MHz RMSE difference anywhere on the globe, provided real time data is available at the four control stations. From the results it is also evident that in addition to the geophysical information from any geographical location, recent past observations of foF2 from these control stations could be used as inputs to a NN for near-real time foF2 predictions. Results also reveal that there is a temporal correlation between measured foF2 values at different locations.
- Full Text:
- Date Issued: 2006
Negotiating impoverishment: Farm worker responses to displacement following land invasions in Zimbabwe's "Fast Track Land Reform Programme"
- Hartnack, Andrew Michael Carl
- Authors: Hartnack, Andrew Michael Carl
- Date: 2006
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/197076 , vital:45834
- Description: This thesis investigates the impacts of sudden, unplanned, and violent displacement on farm workers such as Frank Juwawo during Zimbabwe’s recent Fast Track Land Reform Programme. It seeks to illustrate how the members of a complex community were differentially impacted by displacement and displayed differing abilities to mitigate the resulting social and economic impoverishment. In order to illuminate this particular displacement scenario, this thesis uses theoretical and analytical tools developed in the field of displacement studies, adapting them to suit the kind of displacement experienced by Zimbabwean farm workers. , Thesis (MA) -- Faculty of Humanities, Anthropology, 2006
- Full Text:
- Date Issued: 2006
- Authors: Hartnack, Andrew Michael Carl
- Date: 2006
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/197076 , vital:45834
- Description: This thesis investigates the impacts of sudden, unplanned, and violent displacement on farm workers such as Frank Juwawo during Zimbabwe’s recent Fast Track Land Reform Programme. It seeks to illustrate how the members of a complex community were differentially impacted by displacement and displayed differing abilities to mitigate the resulting social and economic impoverishment. In order to illuminate this particular displacement scenario, this thesis uses theoretical and analytical tools developed in the field of displacement studies, adapting them to suit the kind of displacement experienced by Zimbabwean farm workers. , Thesis (MA) -- Faculty of Humanities, Anthropology, 2006
- Full Text:
- Date Issued: 2006